WorldWideScience

Sample records for rapamycin heterodimerizer system

  1. Rapamycin

    OpenAIRE

    Srivastava, Rupesh K.; Utley, Adam; Shrikant, Protul A.

    2012-01-01

    Vaccines that generate Ag-specific CD8+ T-cell responses of appropriate quality, magnitude and duration are highly desirable. The ability of mTOR to regulate CD8+ T-cell functional differentiation must be exploited for clinical benefit. In a recent paper, we report that varying the regimen of rapamycin administration regulates viral vaccine-induced CD8+ T-cell responses for tumor immunity. These observations validate the use of rapamycin in vaccination strategies and demonstrate the efficacy ...

  2. GPCR Heterodimerization in the Reproductive System: Functional Regulation and Implication for Biodiversity.

    Science.gov (United States)

    Satake, Honoo; Matsubara, Shin; Aoyama, Masato; Kawada, Tsuyoshi; Sakai, Tsubasa

    2013-01-01

    A G protein-coupled receptor (GPCR) functions not only as a monomer or homodimer but also as a heterodimer with another GPCR. GPCR heterodimerization results in the modulation of the molecular functions of the GPCR protomer, including ligand binding affinity, signal transduction, and internalization. There has been a growing body of reports on heterodimerization of multiple GPCRs expressed in the reproductive system and the resultant functional modulation, suggesting that GPCR heterodimerization is closely associated with reproduction including the secretion of hormones and the growth and maturation of follicles and oocytes. Moreover, studies on heterodimerization among paralogs of gonadotropin-releasing hormone (GnRH) receptors of a protochordate, Ciona intestinalis, verified the species-specific regulation of the functions of GPCRs via multiple GnRH receptor pairs. These findings indicate that GPCR heterodimerization is also involved in creating biodiversity. In this review, we provide basic and current knowledge regarding GPCR heterodimers and their functional modulation, and explore the biological significance of GPCR heterodimerization.

  3. Alternative rapamycin treatment regimens mitigate the impact of rapamycin on glucose homeostasis and the immune system

    OpenAIRE

    Arriola Apelo, Sebastian I.; Neuman, Joshua C.; Baar, Emma L.; Syed, Faizan A.; Cummings, Nicole E.; Brar, Harpreet K.; Pumper, Cassidy P.; Kimple, Michelle E.; Lamming, Dudley W.

    2015-01-01

    Summary Inhibition of the mechanistic target of rapamycin (mTOR) signaling pathway by the FDA?approved drug rapamycin has been shown to promote lifespan and delay age?related diseases in model organisms including mice. Unfortunately, rapamycin has potentially serious side effects in humans, including glucose intolerance and immunosuppression, which may preclude the long?term prophylactic use of rapamycin as a therapy for age?related diseases. While the beneficial effects of rapamycin are larg...

  4. Local therapeutic efficacy with reduced systemic side effects by rapamycin-loaded subcapsular microspheres

    NARCIS (Netherlands)

    Falke, Lucas L.; van Vuuren, Stefan H.; Kazazi-Hyseni, Filis; Ramazani, Farshad; Nguyan, Tri Q.; Veldhuis, Gert J.; Maarseveen, Erik M.; Zandstra, Jurjen; Zuidema, Johan; Duque, Luisa F.; Steendam, Rob; Popa, Eliane R.; Kok, Robbert Jan; Goldschmeding, Roe

    Kidney injury triggers fibrosis, the final common pathway of chronic kidney disease (CKD). The increase of CKD prevalence worldwide urgently calls for new therapies. Available systemic treatment such as rapamycin are associated with serious side effects. To study the potential of local antifibrotic

  5. Evaluation of an AAV2-based rapamycin-regulated glial cell line-derived neurotrophic factor (GDNF expression vector system.

    Directory of Open Access Journals (Sweden)

    Piotr Hadaczek

    Full Text Available Effective regulation of transgene product in anatomically circumscribed brain tissue is dependent on the pharmacokinetics of the regulating agent, the kinetics of transcriptional activation and degradation of the transgene product. We evaluated rapamycin-regulated AAV2-GDNF expression in the rat brain (striatum. Regulated (a dual-component system: AAV2-FBZhGDNF + AAV2-TF1Nc and constitutive (CMV-driven expression vectors were compared. Constitutively active AAV2-GDNF directed stable GDNF expression in a dose-dependent manner and it increased for the first month, thereafter reaching a plateau that was maintained over a further 3 months. For the AAV2-regGDNF, rapamycin was administered in a 3-days on/4-days off cycle. Intraperitoneal, oral, and direct brain delivery (CED of rapamycin were evaluated. Two cycles of rapamycin at an intraperitoneal dose of 10 mg/kg gave the highest GDNF level (2.75±0.01 ng/mg protein. Six cycles at 3 mg/kg resulted in lower GDNF values (1.36±0.3 ng/mg protein. Interestingly, CED of rapamycin into the brain at a very low dose (50 ng induced GDNF levels comparable to a 6-week intraperitoneal rapamycin cycle. This study demonstrates the effectiveness of rapamycin regulation in the CNS. However, the kinetics of the transgene in brain tissue, the regulator dosing amount and schedule are critical parameters that influence the kinetics of accumulation and zenith of the encoded transgene product.

  6. Differing Effects of Systemically Administered Rapamycin on Consolidation and Reconsolidation of Context vs. Cued Fear Memories

    Science.gov (United States)

    Glover, Ebony M.; Ressler, Kerry J.; Davis, Michael

    2010-01-01

    Rapamycin, an inhibitor of the mammalian target of rapamycin (mTOR) kinase, has attracted interest as a possible prophylactic for post-traumatic stress disorder (PTSD)-associated fear memories. We report here that although rapamycin (40 mg/kg, i.p.) disrupted the consolidation and reconsolidation of fear-potentiated startle paradigm to a…

  7. Rapid modification of proteins using a rapamycin-inducible tobacco etch virus protease system.

    Directory of Open Access Journals (Sweden)

    Damian J Williams

    2009-10-01

    Full Text Available The ability to disrupt the function of a specific protein on a rapid time scale provides a powerful tool for biomedical research. Specific proteases provide a potential method to selectively cleave a chosen protein, but rapid control of protease activity is difficult.A heterologous expression system for rapid target-directed proteolysis in mammalian cells was developed. The system consists of an inducible NIa protease from the tobacco etch virus (TEVp and a chosen protein into which a TEVp substrate recognition sequence (TRS has been inserted. Inducible activity was conferred to the TEVp using rapamycin-controlled TEVp fragment complementation. TEVp activity was assayed using a FRET-based reporter construct. TEVp expression was well tolerated by mammalian cells and complete cleavage of the substrate was possible. Cleavage at 37 degrees C proceeded exponentially with a time constant of approximately 150 minutes. Attempts to improve cleavage efficiency were hampered by substantial background activity, which was attributed to inherent affinity between the TEVp fragments. A second TEVp assay, based on changes in inactivation of a modified K(V3.4 channel, showed that functional properties of a channel can be using altered using an inducible TEVp system. Similar levels of background activity and variability were observed in both electrophysiological and FRET assays.The results suggested that an optimum level of TEVp expression leading to sufficient inducible activity (with minimal background activity exists but the variability in expression levels between cells makes the present system rather impractical for single cell experiments. The system is likely to be more suitable for experiments in which the cell-to-cell variability is less of an issue; for example, in experiments involving large populations of cells.

  8. Targeting Rapamycin to Podocytes Using a Vascular Cell Adhesion Molecule-1 (VCAM-1-Harnessed SAINT-Based Lipid Carrier System.

    Directory of Open Access Journals (Sweden)

    Ganesh Ram R Visweswaran

    Full Text Available Together with mesangial cells, glomerular endothelial cells and the basement membrane, podocytes constitute the glomerular filtration barrier (GFB of the kidney. Podocytes play a pivotal role in the progression of various kidney-related diseases such as glomerular sclerosis and glomerulonephritis that finally lead to chronic end-stage renal disease. During podocytopathies, the slit-diaphragm connecting the adjacent podocytes are detached leading to severe loss of proteins in the urine. The pathophysiology of podocytopathies makes podocytes a potential and challenging target for nanomedicine development, though there is a lack of known molecular targets for cell selective drug delivery. To identify VCAM-1 as a cell-surface receptor that is suitable for binding and internalization of nanomedicine carrier systems by podocytes, we investigated its expression in the immortalized podocyte cell lines AB8/13 and MPC-5, and in primary podocytes. Gene and protein expression analyses revealed that VCAM-1 expression is increased by podocytes upon TNFα-activation for up to 24 h. This was paralleled by anti-VCAM-1 antibody binding to the TNFα-activated cells, which can be employed as a ligand to facilitate the uptake of nanocarriers under inflammatory conditions. Hence, we next explored the possibilities of using VCAM-1 as a cell-surface receptor to deliver the potent immunosuppressant rapamycin to TNFα-activated podocytes using the lipid-based nanocarrier system Saint-O-Somes. Anti-VCAM-1-rapamycin-SAINT-O-Somes more effectively inhibited the cell migration of AB8/13 cells than free rapamycin and non-targeted rapamycin-SAINT-O-Somes indicating the potential of VCAM-1 targeted drug delivery to podocytes.

  9. Longevity, aging and rapamycin

    OpenAIRE

    Ehninger, Dan; Neff, Frauke; Xie, Kan

    2014-01-01

    The federal drug administration (FDA)-approved compound rapamycin was the first pharmacological agent shown to extend maximal lifespan in both genders in a mammalian species. A major question then is whether the drug slows mammalian aging or if it has isolated effects on longevity by suppressing cancers, the main cause of death in many mouse strains. Here, we review what is currently known about the effects that pharmacological or genetic mammalian target of rapamycin (mTOR) inhibition have o...

  10. Evolution of class B floral homeotic proteins: obligate heterodimerization originated from homodimerization.

    Science.gov (United States)

    Winter, Kai-Uwe; Weiser, Christof; Kaufmann, Kerstin; Bohne, Arend; Kirchner, Charlotte; Kanno, Akira; Saedler, Heinz; Theissen, Günter

    2002-05-01

    The class B floral homeotic genes from the higher eudicot model systems Arabidopsis and Antirrhinum are involved in specifying the identity of petals and stamens during flower development. These genes exist in two different types termed DEF- and GLO-like genes. The proteins encoded by the class B genes are stable and functional in the cell only as heterodimeric complexes of a DEF- and a GLO-like protein. In line with this, heterodimerization is obligate for DNA binding in vitro. The genes whose products have to heterodimerize to be stable and functional are each other's closest relatives within their genomes. This suggests that the respective genes originated by gene duplication, and that heterodimerization is of relative recent origin and evolved from homodimerization. To test this hypothesis we have investigated the dimerization behavior of putative B proteins from phylogenetic informative taxa, employing electrophoretic mobility shift assays and the yeast two-hybrid system. We find that an ancestral B protein from the gymnosperm Gnetum gnemon binds DNA in a sequence-specific manner as a homodimer. Of the two types of B proteins from the monocot Lilium regale, the GLO-like protein is still able to homodimerize, whereas the DEF-like protein binds to DNA only as a heterodimeric complex with the GLO-like protein. These data suggest that heterodimerization evolved in two steps after a gene duplication that gave rise to DEF- and GLO-like genes. Heterodimerization may have originated after the gymnosperm-angiosperm split about 300 MYA but before the monocot-eudicot split 140-200 MYA. Heterodimerization may have become obligate for both types of flowering plant B proteins in the eudicot lineage after the monocot-eudicot split.

  11. Rapamycin carbonate esters

    OpenAIRE

    Rhodes, A; Sandhu, S S; Onis, J. E; McKendrick, John

    2009-01-01

    Certain embodiments include carbonate esters of rapamycin at position 42 that are synthesized by a lipase catalyzed regio-specific process. These compounds or a pharmaceutically acceptable salt thereof are useful in the treatment of organ and tissue transplant rejection, autoimmune disease, proliferative disorder, restenosis, cancer, or microbial infection.

  12. Validation of Heterodimeric TAT-NLS Peptide as a Gene Delivery Enhancer.

    Science.gov (United States)

    Doh, Kyung-Oh

    2015-06-01

    Cationic liposomes have been actively used as gene delivery vehicles despite their unsatisfactory efficiencies because of their relatively low toxicity. In this study, we designed novel heterodimeric peptides as nonviral gene delivery systems from TAT and NLS peptides using cysteine-to-cysteine disulfide bonds between the two. Mixing these heterodimeric peptides with DNA before mixing with lipofectamine resulted in higher transfection efficiencies in MCF-7 breast cancer cells than mixing unmodified TAT, NLS, and a simple mixture of TAT and NLS with DNA, but did not show an adverse effect on cell viability. In gel retardation assays, the DNA binding affinities of heterodimeric peptides were stronger than NLS but weaker than TAT. However, this enhancement was only observed when heterodimeric peptides were premixed with DNA before being mixed with lipofectamine. The described novel transfection-enhancing peptide system produced by the heterodimerization of TAT and NLS peptides followed by simple mixing with DNA, increased the gene transfer efficiency of cationic lipids without enhancing cytotoxicity.

  13. Genome-wide association study for biomarker identification of Rapamycin and Everolimus using a lymphoblastoid cell line system

    Directory of Open Access Journals (Sweden)

    Jing eJiang

    2013-08-01

    Full Text Available The mammalian target of rapamycin (mTOR inhibitors, a set of promising potential anti-cancer agents, has shown response variability among individuals. This study aimed to identify novel biomarkers and mechanisms that might influence the response to Rapamycin and Everolimus. Genome-wide association (GWA analyses involving single nucleotide polymorphisms (SNPs, mRNA and microRNAs microarray data were assessed for association with area under the cytotoxicity dose response curve (AUC of two mTOR inhibitors in 272 human lymphoblastoid cell lines (LCLs. Integrated analysis among SNPs, expression data, microRNA data and AUC values were also performed to help select candidate genes for further functional characterization. Functional validation of candidate genes using siRNA screening in multiple cell lines followed by MTS assays for the two mTOR inhibitors were performed. We found that 16 expression probe sets (genes that overlapped between the two drugs were associated with AUC values of two mTOR inhibitors. 127 and 100 SNPs had P<10-4, while 8 and 10 SNPs had P<10-5 with Rapamycin and Everolimus AUC, respectively. Functional studies indicated that 13 genes significantly altered cell sensitivity to either one or both drugs in at least one cell line. Additionally, one microRNA, miR-10a, was significantly associated with AUC values for both drugs and was shown to repress expression of genes that were associated with AUC and desensitize cells to both drugs. In summary, this study identified genes and a microRNA that might contribute to response to mTOR inhibitors.

  14. Rapamycin: one drug, many effects

    Science.gov (United States)

    Li, Jing; Kim, Sang Gyun; Blenis, John

    2014-01-01

    The mammalian target of rapamycin (mTOR) signaling pathway is a master regulator of cell growth and metabolism. Deregulation of the mTOR pathway has been implicated in a number of human diseases such as cancer, diabetes, obesity, neurological diseases and genetic disorders. Rapamycin, a specific inhibitor of mTOR, has been shown to be useful in the treatment of certain diseases. Here we discuss its mechanism of action and highlight recent findings regarding the effects and limitations of rapamycin monotherapy and the potential utility of combination therapy with rapamycin. PMID:24508508

  15. Rapamycin regulates biochemical metabolites

    OpenAIRE

    Tucci, Paola; Porta, Giovanni; Agostini, Massimiliano; Antonov, Alexey; Garabadgiu, Alexander Vasilievich; Melino, Gerry; Willis, Anne E

    2013-01-01

    The mammalian target of rapamycin (mTOR) kinase is a master regulator of protein synthesis that couples nutrient sensing to cell growth, and deregulation of this pathway is associated with tumorigenesis. p53, and its less investigated family member p73, have been shown to interact closely with mTOR pathways through the transcriptional regulation of different target genes. To investigate the metabolic changes that occur upon inhibition of the mTOR pathway and the role of p73 in this response p...

  16. Inhibition of hemangioma growth using polymer-lipid hybrid nanoparticles for delivery of rapamycin.

    Science.gov (United States)

    Li, Haitao; Teng, Yunfei; Sun, Jin; Liu, Jianyong

    2017-11-01

    Although infantile hemangiomas is benign, its rapid growth may induce serious complications. However, only one drug Hemangeol™ has been approved by US Food and Drug Administration (FDA) to treat infantile hemangiomas. Thus it is necessary to develop novel alternative drugs to treat infantile hemangiomas. Rapamycin is a well-know potent antiangiogenic agent, whereas the daily oral administration of rapamycin exerts undesired metabolic effects due to its inhibition of mechanistic target of rapamycin (mTOR) which is critical in cell metabolism. We hereby developed rapamycin-loaded polymer-lipid hybrid nanoparticles (Rapamycin-PLNPs) as a local controlled release system to realize local and sustained release of rapamycin, aiming to reduce the side effects and frequency of administration of rapamycin. Rapamycin-PLNPs are of a small size (129.1nm), desired drug encapsulation efficiency (63.7%), and sustained drug release for 5 days. Rapamycin-PLNPs were shown to be able to effectively bind to hemangioma endothelia cells (HemECs), induce significant proliferation inhibition and reduce expression of angiogenesis factors in HemECs. The therapeutic effect of Rapamycin-PLNPs against infantile hemangioma in vivo was superior to rapamycin, as reflected by reduced hemangioma volume, weight and microvessel density. Taken together, Rapamycin-PLNPs represent a very promising local approach in the treatment of infantile hemangiomas. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  17. Rapamycin: One Drug, Many Effects

    OpenAIRE

    Li, Jing; Kim, Sang Gyun; Blenis, John

    2014-01-01

    The mammalian target of rapamycin (mTOR) signaling pathway is a master regulator of cell growth and metabolism. Deregulation of the mTOR pathway has been implicated in a number of human diseases such as cancer, diabetes, obesity, neurological diseases and genetic disorders. Rapamycin, a specific inhibitor of mTOR, has been shown to be useful in the treatment of certain diseases. Here we discuss its mechanism of action and highlight recent findings regarding the effects and limitations of rapa...

  18. Phosphatidic acid regulates systemic inflammatory responses by modulating the Akt-mammalian target of rapamycin-p70 S6 kinase 1 pathway.

    Science.gov (United States)

    Lim, Hyung-Kyu; Choi, Young-Ae; Park, Wan; Lee, Taehoon; Ryu, Sung Ho; Kim, Seong-Yong; Kim, Jae-Ryong; Kim, Jung-Hye; Baek, Suk-Hwan

    2003-11-14

    Macrophages are pivotal effector cells in the innate immune system. When microbial products bind to pathogen recognition receptors, macrophages are activated and release a broad array of mediators, such as cytokines, that orchestrate the inflammatory responses of the host. Phosphatidic acid (PA) has been implicated as an important metabolite of phospholipid biosynthesis and in membrane remodeling and has been further suggested to be a crucial second messenger in various cellular signaling events. Here we show that PA is an essential regulator of inflammatory response. Deleterious effects of PA are associated with the secretion of proinflammatory cytokines, such as tumor necrosis factor-alpha, interleukin-1beta, interleukin-6, and the production of nitric oxide, prostaglandin E2, which are predominantly released by macrophage Raw264.7 cells. Furthermore, the administration of PA to mice increased the serum cytokine level. Moreover, direct or lipopolysaccharide-induced PA accumulation by macrophages led to the Akt-dependent activation of the mammalian target of rapamycin-p70 S6 kinase 1, a process required for the induction of inflammatory mediators. These findings demonstrate the importance of the role of PA in systemic inflammatory responses, and provide a potential usefulness as specific targets for the development of therapies.

  19. Interactions between subunits in heterodimeric Ncd molecules.

    Science.gov (United States)

    Kocik, Elzbieta; Skowronek, Krzysztof J; Kasprzak, Andrzej A

    2009-12-18

    The nonprocessive minus-end-directed kinesin-14 Ncd is involved in the organization of the microtubule (MT) network during mitosis. Only one of the two motor domains is involved in the interaction with the MT. The other head is tethered to the bound one. Here we prepared, purified, and characterized mutated Ncd molecules carrying point mutations in one of the heads, thus producing heterodimeric motors. The mutations tested included substitutions in Switch I and II: R552A, E585A, and E585D; the decoupling mutant N600K; and a deletion in the motor domain in one of the subunits resulting in a single-headed molecule (NcN). These proteins were isolated by two sequential affinity chromatography steps, followed by measurements of their affinities to MT, enzymatic properties, and the velocity of the microtubule gliding test in vitro. A striking observation is a low affinity of the single-headed NcN for MT both without nucleotides and in the presence of 5'-adenylyl-beta,gamma-imidodiphosphate, implying that the tethered head has a profound effect on the structure of the Ncd-MT complex. Mutated homodimers had no MT-activated ATPase and no motility, whereas NcN had motility comparable with that of the wild type Ncd. Although the heterodimers had one fully active and one inactive head, the ATPase and motility of Ncd heterodimers varied dramatically, clearly demonstrating that interactions between motor domains exist in Ncd. We also show that the bulk property of dimeric proteins that interact with the filament with only one of its heads depends also on the distribution of the filament-interacting subunits.

  20. Heterodimeric TALENs induce targeted heritable mutations in the crustacean Daphnia magna

    Directory of Open Access Journals (Sweden)

    Akiko Naitou

    2015-02-01

    Full Text Available Transcription activator-like effector nucleases (TALENs are artificial nucleases harboring a customizable DNA-binding domain and a FokI nuclease domain. The high specificity of the DNA-binding domain and the ease of design have enabled researchers to use TALENs for targeted mutagenesis in various organisms. Here, we report the development of TALEN-dependent targeted gene disruption in the crustacean Daphnia magna, the emerging model for ecological and toxicological genomics. First, a reporter transgene DsRed2 (EF1α-1::DsRed2 was targeted. Using the Golden Gate method with a GoldyTALEN scaffold, we constructed homodimeric and heterodimeric TALENs containing wild-type and ELD/KKR FokI domains. mRNAs that coded for either the customized homodimeric or heterodimeric TALENs were injected into one-cell-stage embryos. The high mortality of embryos injected with homodimeric TALEN mRNAs prevented us from detecting mutations. In contrast, embryos injected with heterodimeric TALEN mRNAs survived and 78%–87% of the adults lost DsRed2 fluorescence in a large portion of cells throughout the body. In addition, these adults produced non-fluorescent progenies, all of which carried mutations at the dsRed2 locus. We also tested heterodimeric TALENs targeted for the endogenous eyeless gene and found that biallelic mutations could be transmitted through germ line cells at a rate of up to 22%. Both somatic and heritable mutagenesis efficiencies of TALENs were higher than those of the CRISPR/Cas9 system that we recently developed. These results suggest that the TALEN system may efficiently induce heritable mutations into the target genes, which will further contribute to the progress of functional genomics in D. magna.

  1. Surface Engineering of Porous Silicon Microparticles for Intravitreal Sustained Delivery of Rapamycin

    OpenAIRE

    Nieto, Alejandra; Hou, Huiyuan; Moon, Sang Woong; Sailor, Michael J.; Freeman, William R.; Cheng, Lingyun

    2015-01-01

    Mild oxidation and subsequent silanization of the porous silicon (pSi) rendered the resultant pSi particles optimized for rapamycin loading/release as an intravitreal injectable delivery system. The system slowly released rapamycin and safely resided in rabbit vitreous more than 8 weeks.

  2. Microsphere-Based Rapamycin Delivery, Systemic Versus Local Administration in a Rat Model of Renal Ischemia/Reperfusion Injury

    NARCIS (Netherlands)

    Zandstra, Jurjen; van Beuge, Marike M.; Zuidema, Johan; Petersen, Arjen H.; Staal, Mark; Duque, Luisa F.; Rodriguez, Sergio; Lathuile, Audrey A. R.; Veldhuis, Gert J.; Steendam, Rob; Bank, Ruud A.; Popa, Eliane R.

    2015-01-01

    The increasing prevalence and treatment costs of kidney diseases call for innovative therapeutic strategies that prevent disease progression at an early stage. We studied a novel method of subcapsular injection of monodisperse microspheres, to use as a local delivery system of drugs to the kidney.

  3. Rapamycin promotes osteogenesis under inflammatory conditions.

    Science.gov (United States)

    Li, Xing; Chang, Bei; Wang, Banchao; Bu, Wenhuan; Zhao, Liang; Liu, Jie; Meng, Lin; Wang, Lu; Xin, Ying; Wang, Dandan; Tang, Qi; Zheng, Changyu; Sun, Hongchen

    2017-12-01

    Chronic periodontitis, a common oral disease, usually results in irreversible bone resorption. Bone regeneration is a complex process between bone‑forming activity of osteoblasts and bone‑resorbing activity of osteoclasts, and still remains a challenge for physicians clinically. A previous study demonstrated that the mechanistic target of rapamycin signaling pathway is involved in osteogenic differentiation of mesenchymal stromal cells. Herein, whether rapamycin could be used to induce osteogenic differentiation of primary bone marrow‑derived mesenchymal stem cells (BMSCs) in vitro and promote new bone formation in vivo were evaluated. The results demonstrated that rapamycin alone was not enough to fully induce osteoblast differentiation in vitro and enhanced bone regeneration in vivo. Interestingly, rapamycin in rapamycin plus lipopolysaccharide (LPS)‑treated BMSCs significantly increased the gene expression levels of Sp7 transcription factor, runt related transcription factor 2, alkaline phosphatase (ALP) and collagen I (Col I), ALP activity, and calcium nodule at different time points in vitro, indicating that osteoblast differentiation occurs by rapamycin when BMSCs are exposed to LPS simultaneously. It was also demonstrated that rapamycin in rapamycin plus LPS‑treated rats promoted bone regeneration in vivo. These results suggest that rapamycin may influence osteoblast differentiation and new bone formation after LPS induces an inflammatory environment. Rapamycin may be used to treat periodontitis associated with bone loss in future clinical practice.

  4. Divergent tissue and sex effects of rapamycin on the proteasome-chaperone network of old mice

    Directory of Open Access Journals (Sweden)

    Karl Andrew Rodriguez

    2014-11-01

    Full Text Available Rapamycin, an allosteric inhibitor of the mTOR kinase, increases longevity in mice in a sex-specific manner. In contrast to the widely accepted theory that a loss of proteasome activity is detrimental to both life- and healthspan, biochemical studies in vitro reveal that rapamycin inhibits 20S proteasome peptidase activity. We tested if this unexpected finding is also evident after chronic rapamycin treatment in vivo by measuring peptidase activities for both the 26S and 20S proteasome in liver, fat, and brain tissues of old, male and female mice fed encapsulated chow containing 2.24mg/kg (14 ppm rapamycin for 6 months. Further we assessed if rapamycin altered expression of the chaperone proteins known to interact with the proteasome-mediated degradation system (PMDS, heat shock factor 1 (HSF1, and the levels of key mTOR pathway proteins. Rapamycin had little effect on liver proteasome activity in either gender, but increased proteasome activity in female brain lysates and lowered its activity in female fat tissue. Rapamycin-induced changes in molecular chaperone levels were also more substantial in tissues from female animals. Furthermore, mTOR pathway proteins showed more significant changes in female tissues compared to those from males. These data show collectively that there are divergent tissue and sex effects of rapamycin on the proteasome-chaperone network and that these may be linked to the disparate effects of rapamycin on males and females. Further our findings suggest that rapamycin induces indirect regulation of the PMDS/heat-shock response through its modulation of the mTOR pathway rather than via direct interactions between rapamycin and the proteasome.

  5. Rapamycin prevents drug seeking via disrupting reconsolidation of reward memory in rats.

    Science.gov (United States)

    Lin, Jue; Liu, Lingqi; Wen, Quan; Zheng, Chunming; Gao, Yang; Peng, Shuxian; Tan, Yalun; Li, Yanqin

    2014-01-01

    The maladaptive drug memory developed between the drug-rewarding effect and environmental cues contributes to difficulty in preventing drug relapse. Established reward memories can be disrupted by pharmacologic interventions following their reactivation. Rapamycin, an inhibitor of mammalian target of rapamycin (mTOR) kinase, has been proved to be involved in various memory consolidation. However, it is less well characterized in drug memory reconsolidation. Using a conditioned place preference (CPP) procedure, we examined the effects of systemically administered rapamycin on reconsolidation of drug memory in rats. We found that systemically administered rapamycin (0.1 or 10 mg/kg, i.p.) after re-exposure to drug-paired environment, dose dependently decreased the expression of CPP 1 d later, and the effect lasted for up to 14 d and could not be reversed by a priming injection of morphine. The effect of rapamycin on morphine-associated memory was specific to drug-paired context, and rapamycin had no effect on subsequent CPP expression when rats were exposed to saline-paired context or homecage. These results indicated that systemic administration of rapamycin after memory reactivation can persistently inhibit the drug seeking behaviour via disruption of morphine memory reconsolidation in rats. Additionally, the effect of rapamycin on memory reconsolidation was reproduced in cocaine CPP and alcohol CPP. Furthermore, rapamycin did not induce conditioned place aversion and had no effect on locomotor activity and anxiety behaviour. These findings suggest that rapamycin could erase the acquired drug CPP in rats, and that mTOR activity plays an important role in drug reconsolidation and is required for drug relapse.

  6. Rapamycin up-regulates triglycerides in hepatocytes by down-regulating Prox1.

    Science.gov (United States)

    Kwon, Sora; Jeon, Ji-Sook; Kim, Su Bin; Hong, Young-Kwon; Ahn, Curie; Sung, Jung-Suk; Choi, Inho

    2016-02-27

    Although the prolonged use of rapamycin may cause unwanted side effects such as hyperlipidemia, the underlying mechanism remains unknown. Prox1 is a transcription factor responsible for the development of several tissues including lymphatics and liver. There is growing evidences that Prox1 participates in metabolism in addition to embryogenesis. However, whether Prox1 is directly related to lipid metabolism is currently unknown. HepG2 human hepatoma cells were treated with rapamycin and total lipids were analyzed by thin layer chromatography. The effect of rapamycin on the expression of Prox1 was determined by western blotting. To investigate the role of Prox1 in triglycerides regulation, siRNA and overexpression system were employed. Rapamycin was injected into mice for 2 weeks and total lipids and proteins in liver were measured by thin layer chromatography and western blot analysis, respectively. Rapamycin up-regulated the amount of triglyceride and down-regulated the expression of Prox1 in HepG2 cells by reducing protein half-life but did not affect its transcript. The loss-of-function of Prox1 was coincident with the increase of triglycerides in HepG2 cells treated with rapamycin. The up-regulation of triglycerides by rapamycin in HepG2 cells reverted to normal levels by the compensation of Prox1 using the overexpression system. Rapamycin also down-regulated Prox1 expression but increased triglycerides in mouse liver. This study suggests that rapamycin can increase the amount of triglycerides by down-regulating Prox1 expression in hepatocytes, which means that the mammalian target of rapamycin (mTOR) signaling is important for the regulation of triglycerides by maintaining Prox1 expression.

  7. Rapamycin alleviates oxidative stress-induced damage in rat erythrocytes.

    Science.gov (United States)

    Singh, Abhishek Kumar; Singh, Sandeep; Garg, Geetika; Rizvi, Syed Ibrahim

    2016-10-01

    An imbalanced cellular redox system promotes the production of reactive oxygen species (ROS) that may lead to oxidative stress-mediated cell death. Erythrocytes are the best-studied model of antioxidant defense mechanism. The present study was undertaken to investigate the effect of the immunosuppressant drug rapamycin, an inducer of autophagy, on redox balance of erythrocytes and blood plasma of oxidatively challenged rats. Male Wistar rats were oxidatively challenged with HgCl2 (5 mg/kg body mass (b.m.)). A significant (p membrane redox system (PMRS), intracellular Ca2+ influx, lipid peroxidation (LPO), osmotic fragility, plasma protein carbonyl (PCO) content, and plasma advanced oxidation protein products (AOPP) and simultaneously significant reduction in glutathione (GSH) level and ferric reducing ability of plasma (FRAP) were observed in rats exposed to HgCl2. Furthermore, rapamycin (0.5 mg/kg b.m.) provided significant protection against HgCl2-induced alterations in rat erythrocytes and plasma by reducing ROS production, PMRS activity, intracellular Ca2+ influx, LPO, osmotic fragility, PCO content, and AOPP and also restored the level of antioxidant GSH and FRAP. Our observations provide evidence that rapamycin improves redox status and attenuates oxidative stress in oxidatively challenged rats. Our data also demonstrate that rapamycin is a comparatively safe immunosuppressant drug.

  8. Microcystic Lymphatic Malformation Successfully Treated With Topical Rapamycin.

    Science.gov (United States)

    García-Montero, Pablo; Del Boz, Javier; Sanchez-Martínez, Miguel; Escudero Santos, Isabel María; Baselga, Eulalia

    2017-05-01

    Microcystic lymphatic malformations (MLM) are low-flow vascular malformations composed of multiple small cysts. MLM usually affect deep-lying structures, which makes their treatment even more difficult and complex. A novel and interesting treatment is rapamycin, a mammalian target of rapamycin inhibitor that when orally administrated has offered favorable results. However, until recently, topical rapamycin had not been used in the treatment of MLM. Case 1 is a girl aged 13 years with extensive MLM affecting the muscles in the right buttock. The patient had received frequent cycles of cryotherapy, but they had failed to control the associated symptoms. In the previous 12 months, the patient had reported greater discomfort, swelling, exudate, and superinfection of the affected region. Because no specific treatment has yet been approved for MLM, and as a step before the use of aggressive systemic or intralesional treatments, it was decided to initiate treatment with 1% rapamycin ointment. After 4 months of treatment, the patient presented a marked improvement, with a significant reduction of associated complications and no major side effects. Case 2 is a boy aged 5 years who underwent surgery for an intergluteal lipoblastoma at 3 weeks of life and developed a MLM on the scar 6 months afterward. The lesion showed slow growth and continuous exudation with frequent episodes of superinfection. Treatments with laser multiplex and intralesional bleomycin were performed unsuccessfully. In the previous 4 months, the patient had been treated with 1% rapamycin ointment with significant improvement and no side effects. Copyright © 2017 by the American Academy of Pediatrics.

  9. Inhibition of akt enhances the chemopreventive effects of topical rapamycin in mouse skin

    Science.gov (United States)

    Dickinson, Sally E; Janda, Jaroslav; Criswell, Jane; Blohm-Mangone, Karen; Olson, Erik R.; Liu, Zhonglin; Barber, Christie; Rusche, Jadrian J.; Petricoin, Emmanuel; Calvert, Valerie; Einspahr, Janine G.; Dickinson, Jesse; Stratton, Steven P.; Curiel-Lewandrowski, Clara; Saboda, Kathylynn; Hu, Chengcheng; Bode, Ann M.; Dong, Zigang; Alberts, David S.; Bowden, G. Timothy

    2016-01-01

    The PI3Kinase/Akt/mTOR pathway has important roles in cancer development for multiple tumor types, including UV-induced non-melanoma skin cancer. Immunosuppressed populations are at increased risk of aggressive cutaneous squamous cell carcinoma (SCC). Individuals who are treated with rapamycin, (sirolimus, a classical mTOR inhibitor) have significantly decreased rates of developing new cutaneous SCCs compared to those that receive traditional immunosuppression. However, systemic rapamycin use can lead to significant adverse events. Here we explored the use of topical rapamycin as a chemopreventive agent in the context of solar simulated light (SSL)-induced skin carcinogenesis. In SKH-1 mice, topical rapamycin treatment decreased tumor yields when applied after completion of 15 weeks of SSL exposure compared to controls. However, applying rapamycin during SSL exposure for 15 weeks, and continuing for 10 weeks after UV treatment, increased tumor yields. We also examined whether a combinatorial approach might result in more significant tumor suppression by rapamycin. We validated that rapamycin causes increased Akt (S473) phosphorylation in the epidermis after SSL, and show for the first time that this dysregulation can be inhibited in vivo by a selective PDK1/Akt inhibitor, PHT-427. Combining rapamycin with PHT-427 on tumor prone skin additively caused a significant reduction of tumor multiplicity compared to vehicle controls. Our findings indicate that patients taking rapamycin should avoid sun exposure, and that combining topical mTOR inhibitors and Akt inhibitors may be a viable chemoprevention option for individuals at high risk for cutaneous SCC.

  10. Inhibition of HIF-2.alpha. heterodimerization with HIF1.beta. (ARNT)

    Energy Technology Data Exchange (ETDEWEB)

    Bruick, Richard K.; Caldwell, Charles G.; Frantz, Doug E.; Gardner, Kevin H.; MacMillan, John B.; Scheuermann, Thomas H.; Tambar, Uttam K.

    2017-09-12

    Provided is a method of inhibiting heterodimerization of HIF-2.alpha. to HIF1.beta. (ARNT) comprising binding certain small molecules to the HIF-2.alpha. PAS-B domain cavity but not to HIF1.alpha. and inhibiting HIF-2.alpha. heterodimerization to HIF1.beta. (ARNT) but not inhibiting HIF1.alpha. heterodimerization to HIF1.beta. (ARNT). Those certain small molecules are also referenced synonymously as HIF2-HDI and HIF2.alpha. heterodimerization inhibitors and also simply as certain small molecules.

  11. Towards natural mimetics of metformin and rapamycin.

    Science.gov (United States)

    Aliper, Alexander; Jellen, Leslie; Cortese, Franco; Artemov, Artem; Karpinsky-Semper, Darla; Moskalev, Alexey; Swick, Andrew G; Zhavoronkov, Alex

    2017-11-15

    Aging is now at the forefront of major challenges faced globally, creating an immediate need for safe, widescale interventions to reduce the burden of chronic disease and extend human healthspan. Metformin and rapamycin are two FDA-approved mTOR inhibitors proposed for this purpose, exhibiting significant anti-cancer and anti-aging properties beyond their current clinical applications. However, each faces issues with approval for off-label, prophylactic use due to adverse effects. Here, we initiate an effort to identify nutraceuticals-safer, naturally-occurring compounds-that mimic the anti-aging effects of metformin and rapamycin without adverse effects. We applied several bioinformatic approaches and deep learning methods to the Library of Integrated Network-based Cellular Signatures (LINCS) dataset to map the gene- and pathway-level signatures of metformin and rapamycin and screen for matches among over 800 natural compounds. We then predicted the safety of each compound with an ensemble of deep neural network classifiers. The analysis revealed many novel candidate metformin and rapamycin mimetics, including allantoin and ginsenoside (metformin), epigallocatechin gallate and isoliquiritigenin (rapamycin), and withaferin A (both). Four relatively unexplored compounds also scored well with rapamycin. This work revealed promising candidates for future experimental validation while demonstrating the applications of powerful screening methods for this and similar endeavors.

  12. Rapamycin bypasses vesicle-mediated signaling events to activate Gln3 in Saccharomyces cerevisiae

    Science.gov (United States)

    Puria, Rekha

    2008-01-01

    Growth of Saccharomyces cerevisiae in poor nitrogen sources or exposure to the Tor inhibitor rapamycin results in expression of the nitrogen catabolite repressed (NCR) genes whose products are involved in scavenging and metabolizing nitrogen. The NCR genes are regulated by the GATA-like transactivators Gln3 and Gat1, which are thought to be under control of the rapamycin-sensitive Tor complex 1 (TORC1). We have recently shown that Gln3 nuclear translocation in response to nitrogen source quality but not in response to rapamycin requires Golgi to endosome trafficking. These and previous findings that several TORC1 components localize to low density endomembranes are discussed in a model that underscores a prominent role for the vesicular trafficking system in facilitating molecular interactions in response to nitrogen source. In addition, these findings have important implications for Tor signaling and rapamycin mechanism of action, both in yeast and in metazoans. PMID:19430540

  13. Brain Injury-Induced Synaptic Reorganization in Hilar Inhibitory Neurons Is Differentially Suppressed by Rapamycin.

    Science.gov (United States)

    Butler, Corwin R; Boychuk, Jeffery A; Smith, Bret N

    2017-01-01

    Following traumatic brain injury (TBI), treatment with rapamycin suppresses mammalian (mechanistic) target of rapamycin (mTOR) activity and specific components of hippocampal synaptic reorganization associated with altered cortical excitability and seizure susceptibility. Reemergence of seizures after cessation of rapamycin treatment suggests, however, an incomplete suppression of epileptogenesis. Hilar inhibitory interneurons regulate dentate granule cell (DGC) activity, and de novo synaptic input from both DGCs and CA3 pyramidal cells after TBI increases their excitability but effects of rapamycin treatment on the injury-induced plasticity of interneurons is only partially described. Using transgenic mice in which enhanced green fluorescent protein (eGFP) is expressed in the somatostatinergic subset of hilar inhibitory interneurons, we tested the effect of daily systemic rapamycin treatment (3 mg/kg) on the excitability of hilar inhibitory interneurons after controlled cortical impact (CCI)-induced focal brain injury. Rapamycin treatment reduced, but did not normalize, the injury-induced increase in excitability of surviving eGFP+ hilar interneurons. The injury-induced increase in response to selective glutamate photostimulation of DGCs was reduced to normal levels after mTOR inhibition, but the postinjury increase in synaptic excitation arising from CA3 pyramidal cell activity was unaffected by rapamycin treatment. The incomplete suppression of synaptic reorganization in inhibitory circuits after brain injury could contribute to hippocampal hyperexcitability and the eventual reemergence of the epileptogenic process upon cessation of mTOR inhibition. Further, the cell-selective effect of mTOR inhibition on synaptic reorganization after CCI suggests possible mechanisms by which rapamycin treatment modifies epileptogenesis in some models but not others.

  14. Low-dose rapamycin extends lifespan in a mouse model of mtDNA depletion syndrome.

    Science.gov (United States)

    Siegmund, Stephanie E; Yang, Hua; Sharma, Rohit; Javors, Martin; Skinner, Owen; Mootha, Vamsi; Hirano, Michio; Schon, Eric A

    2017-12-01

    Mitochondrial disorders affecting oxidative phosphorylation (OxPhos) are caused by mutations in both the nuclear and mitochondrial genomes. One promising candidate for treatment is the drug rapamycin, which has been shown to extend lifespan in multiple animal models, and which was previously shown to ameliorate mitochondrial disease in a knock-out mouse model lacking a nuclear-encoded gene specifying an OxPhos structural subunit (Ndufs4). In that model, relatively high-dose intraperitoneal rapamycin extended lifespan and improved markers of neurological disease, via an unknown mechanism. Here, we administered low-dose oral rapamycin to a knock-in (KI) mouse model of authentic mtDNA disease, specifically, progressive mtDNA depletion syndrome, resulting from a mutation in the mitochondrial nucleotide salvage enzyme thymidine kinase 2 (TK2). Importantly, low-dose oral rapamycin was sufficient to extend Tk2KI/KI mouse lifespan significantly, and did so in the absence of detectable improvements in mitochondrial dysfunction. We found no evidence that rapamycin increased survival by acting through canonical pathways, including mitochondrial autophagy. However, transcriptomics and metabolomics analyses uncovered systemic metabolic changes pointing to a potential 'rapamycin metabolic signature.' These changes also implied that rapamycin may have enabled the Tk2KI/KI mice to utilize alternative energy reserves, and possibly triggered indirect signaling events that modified mortality through developmental reprogramming. From a therapeutic standpoint, our results support the possibility that low-dose rapamycin, while not targeting the underlying mtDNA defect, could represent a crucial therapy for the treatment of mtDNA-driven, and some nuclear DNA-driven, mitochondrial diseases. © The Author 2017. Published by Oxford University Press.

  15. Blocking mTOR Signalling with Rapamycin Ameliorates Imiquimod-induced Psoriasis in Mice.

    Science.gov (United States)

    Bürger, Claudia; Shirsath, Nitesh; Lang, Victoria; Diehl, Sandra; Kaufmann, Roland; Weigert, Andreas; Han, Ying-Ying; Ringel, Christian; Wolf, Peter

    2017-10-02

    The mTOR (mechanistic target of rapamycin) inhibitor rapamycin has long been known for its immune suppressive properties, but it has shown limited therapeutic success when given systemically to patients with psoriasis. Recent data have shown that the mTOR pathway is hyperactivated in lesional psoriatic skin, which probably contributes to the disease by interfering with maturation of keratinocytes. This study investigated the effect of topical rapamycin treatment in an imiquimod-induced psoriatic mouse model. The disease was less severe if the mice had received rapamycin treatment. Immunohistological analysis revealed that rapamycin not only prevented the activation of mTOR signalling (P-mTOR and P-S6 levels), but almost normalized the expression of epidermal differentiation markers. In addition, the influx of innate immune cells into the draining lymph nodes was partially reduced by rapamycin treatment. These data emphasize the role of mTOR signalling in the pathogenesis of psoriasis, and support the investigation of topical mTOR inhibition as a novel anti-psoriatic strategy.

  16. Intranasal Rapamycin Rescues Mice from Staphylococcal Enterotoxin B-Induced Shock

    Directory of Open Access Journals (Sweden)

    Teresa Krakauer

    2012-09-01

    Full Text Available Staphylococcal enterotoxin B (SEB and related exotoxins produced by Staphylococcus aureus are potent activators of the immune system and cause toxic shock in humans. Currently there is no effective treatment except for the use of intravenous immunoglobulins administered shortly after SEB exposure. Intranasal SEB induces long-lasting lung injury which requires prolonged drug treatment. We investigated the effects of rapamycin, an immunosuppressive drug used to prevent graft rejection, by intranasal administration in a lethal mouse model of SEB-induced shock. The results show that intranasal rapamycin alone delivered as late as 17 h after SEB protected 100% of mice from lethal shock. Additionally, rapamycin diminished the weight loss and temperature fluctuations elicited by SEB. Intranasal rapamycin attenuated lung MCP-1, IL-2, IL-6, and IFNγ by 70%, 30%, 64%, and 68% respectively. Furthermore, short courses (three doses of rapamycin were sufficient to block SEB-induced shock. Intranasal rapamycin represents a novel use of an immunosuppressant targeting directly to site of toxin exposure, reducing dosages needed and allowing a wider therapeutic window.

  17. Rapamycin Influences the Efficiency of Fertilization and Development in the Mouse: A Role for Autophagic Activation

    Directory of Open Access Journals (Sweden)

    Geun-Kyung Lee

    2016-08-01

    Full Text Available The mammalian target of rapamycin (mTOR regulates cellular processes such as cell growth, metabolism, transcription, translation, and autophagy. Rapamycin is a selective inhibitor of mTOR, and induces autophagy in various systems. Autophagy contributes to clearance and recycling of macromolecules and organelles in response to stress. We previously reported that vitrified-warmed mouse oocytes show acute increases in autophagy during warming, and suggested that it is a natural response to cold stress. In this follow-up study, we examined whether the modulation of autophagy influences survival, fertilization, and developmental rates of vitrified-warmed mouse oocytes. We used rapamycin to enhance autophagy in metaphase II (MII oocytes before and after vitrification. The oocytes were then subjected to in vitro fertilization (IVF. The fertilization and developmental rates of vitrified-warmed oocytes after rapamycin treatment were significantly lower than those for control groups. Modulation of autophagy with rapamycin treatment shows that rapamycin-induced autophagy exerts a negative influence on fertilization and development of vitrified-warmed oocytes.

  18. Cargo and Carrier Effects of Rapamycin-Loaded Perfluorocarbon Nanoparticles

    Science.gov (United States)

    Bibee, Kristin Page

    Nanoparticle-based drug delivery has been championed as a means to increase local delivery of therapeutics while decreasing systemic drug exposure. By targeting the particles, and therefore the drugs, to diseased cells of interest, healthy cells will be spared and side effects avoided. This delivery mechanism would be particularly useful for drugs that interfere with cell growth and proliferation pathways, as blocking proliferation in normal cells leads to significant patient morbidity. Rapamycin is a macrolide and a known inhibitor of mTORC1, a protein complex that plays a crucial role in protein translation and cell growth. This work demonstrates the effects of rapamycin complexed with a nanoparticle carrier on two distinct pathologies: a new triple negative breast cancer cell line and a conventional mouse model of muscular dystrophy (mdx). Rapamycin is able to alter mitochondrial function and thus metabolism in both free and nanoparticle-delivered form without killing the cells. Although nanoparticles are considered to be a benign carrier, this work shows that perfluorocarbon nanoparticles are able to induce autophagy in vitro. The benefits of autophagy induction in cancer cells is cell and stage specific, but has been reported to be useful for radiosensitization of triple negative breast cancers. Additionally, the particles are shown to induce autophagy in the mdx model of Duchenne Muscular Dystrophy and, when loaded with rapamycin, dramatically improve strength even in older animals with muscular dystrophy. Overall, this work enhances our understanding of the cellular effects of perfluorocarbon nanoparticles in two different disease models and enhances prospects for clinical translation of nanoparticle-based drug delivery.

  19. Antibody engineering using phage display with a coiled-coil heterodimeric Fv antibody fragment.

    Directory of Open Access Journals (Sweden)

    Xinwei Wang

    Full Text Available A Fab-like antibody binding unit, ccFv, in which a pair of heterodimeric coiled-coil domains was fused to V(H and V(L for Fv stabilization, was constructed for an anti-VEGF antibody. The anti-VEGF ccFv showed the same binding affinity as scFv but significantly improved stability and phage display level. Furthermore, phage display libraries in the ccFv format were constructed for humanization and affinity maturation of the anti-VEGF antibody. A panel of V(H frameworks and V(H-CDR3 variants, with a significant improvement in affinity and expressibility in both E. coli and yeast systems, was isolated from the ccFv phage libraries. These results demonstrate the potential application of the ccFv antibody format in antibody engineering.

  20. Evidence for Heterodimerization and Functional Interaction of the Angiotensin Type 2 Receptor and the Receptor MAS.

    Science.gov (United States)

    Leonhardt, Julia; Villela, Daniel C; Teichmann, Anke; Münter, Lisa-Marie; Mayer, Magnus C; Mardahl, Maibritt; Kirsch, Sebastian; Namsolleck, Pawel; Lucht, Kristin; Benz, Verena; Alenina, Natalia; Daniell, Nicholas; Horiuchi, Masatsugu; Iwai, Masaru; Multhaup, Gerhard; Schülein, Ralf; Bader, Michael; Santos, Robson A; Unger, Thomas; Steckelings, Ulrike Muscha

    2017-06-01

    The angiotensin type 2 receptor (AT2R) and the receptor MAS are receptors of the protective arm of the renin-angiotensin system. They mediate strikingly similar actions. Moreover, in various studies, AT2R antagonists blocked the effects of MAS agonists and vice versa. Such cross-inhibition may indicate heterodimerization of these receptors. Therefore, this study investigated the molecular and functional interplay between MAS and the AT2R. Molecular interactions were assessed by fluorescence resonance energy transfer and by cross correlation spectroscopy in human embryonic kidney-293 cells transfected with vectors encoding fluorophore-tagged MAS or AT2R. Functional interaction of AT2R and MAS was studied in astrocytes with CX3C chemokine receptor-1 messenger RNA expression as readout. Coexpression of fluorophore-tagged AT2R and MAS resulted in a fluorescence resonance energy transfer efficiency of 10.8 ± 0.8%, indicating that AT2R and MAS are capable to form heterodimers. Heterodimerization was verified by competition experiments using untagged AT2R and MAS. Specificity of dimerization of AT2R and MAS was supported by lack of dimerization with the transient receptor potential cation channel, subfamily C-member 6. Dimerization of the AT2R was abolished when it was mutated at cysteine residue 35. AT2R and MAS stimulation with the respective agonists, Compound 21 or angiotensin-(1-7), significantly induced CX3C chemokine receptor-1 messenger RNA expression. Effects of each agonist were blocked by an AT2R antagonist (PD123319) and also by a MAS antagonist (A-779). Knockout of a single of these receptors made astrocytes unresponsive for both agonists. Our results suggest that MAS and the AT2R form heterodimers and that-at least in astrocytes-both receptors functionally depend on each other. © 2017 American Heart Association, Inc.

  1. A Signal-On Fluorosensor Based on Quench-Release Principle for Sensitive Detection of Antibiotic Rapamycin

    Directory of Open Access Journals (Sweden)

    Hee-Jin Jeong

    2015-03-01

    Full Text Available An antibiotic rapamycin is one of the most commonly used immunosuppressive drugs, and also implicated for its anti-cancer activity. Hence, the determination of its blood level after organ transplantation or tumor treatment is of great concern in medicine. Although there are several rapamycin detection methods, many of them have limited sensitivity, and/or need complicated procedures and long assay time. As a novel fluorescent biosensor for rapamycin, here we propose “Q’-body”, which works on the fluorescence quench-release principle inspired by the antibody-based quenchbody (Q-body technology. We constructed rapamycin Q’-bodies by linking the two interacting domains FKBP12 and FRB, whose association is triggered by rapamycin. The fusion proteins were each incorporated position-specifically with one of fluorescence dyes ATTO520, tetramethylrhodamine, or ATTO590 using a cell-free translation system. As a result, rapid rapamycin dose-dependent fluorescence increase derived of Q’-bodies was observed, especially for those with ATTO520 with a lowest detection limit of 0.65 nM, which indicates its utility as a novel fluorescent biosensor for rapamycin.

  2. Characterization of an insect heterodimeric voltage-gated sodium channel with unique alternative splicing mode.

    Science.gov (United States)

    Jiang, Xuan-Zhao; Pei, Yu-Xia; Lei, Wei; Wang, Ke-Yi; Shang, Feng; Jiang, Hong-Bo; Wang, Jin-Jun

    2017-01-01

    Recent discovery of the heterodimeric voltage-gated sodium channels (Na v ) in two aphid species, Acyrthosiphon pisum and Myzus persicae, aroused interest in exploring whether this kind of channel is conserved for aphids. Herewith, we aim to provide evidence for the conservation of heterodimeric Na v s in aphids and investigate whether they have unique splicing patterns. We found that the only identifiable Na v from Toxoptera citricida consisted of two subunits, forming a heterodimeric Na v , which carried an atypical "DENS" ion selectivity filter and a conventional "MFM" inactivation gate, confirming the heterodimeric Na v s' conservation within aphids. These unique heterodimeric channels may form a new Na v subfamily, specific to aphids. A more ancient member of four-domain Na v homolog was well preserved in T. citricida, carrying a typical "DEEA" and "MFL" motif. The presence of "DENS" in mammalian Na x s and "DEKT" in a fungus Na v suggested that the heterodimeric Na v s may still preserve Na + permeability. Sequencing 46 clones from nymphs and adults exposed unique splicing patterns for this heterodimeric Na v from T. citricida, revealing 7 alternatively spliced exons, evidencing that exon 5 was no longer unique to Bombyx mori, and exon k/l was semi-mutually exclusive. Two previously undescribed optional exons and a SNP site seemingly unique to aphids were identified. In conclusion, the dimeric Na v s might form a new aphids-specific heterodimeric N a v subfamily. This dimeric Na v from T. citricida was characterized with distinguishable alternative splicing modes, exemplified by the discovery of two novel alternative exons and unique usage patterns of alternative exons. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Covalent modification of pericardial patches for sustained rapamycin delivery inhibits venous neointimal hyperplasia

    Science.gov (United States)

    Bai, Hualong; Lee, Jung Seok; Chen, Elizabeth; Wang, Mo; Xing, Ying; Fahmy, Tarek M.; Dardik, Alan

    2017-01-01

    Prosthetic grafts and patches are commonly used in cardiovascular surgery, however neointimal hyperplasia remains a significant concern, especially under low flow conditions. We hypothesized that delivery of rapamycin from nanoparticles (NP) covalently attached to patches allows sustained site-specific delivery of therapeutic agents targeted to inhibit localized neointimal hyperplasia. NP were covalently linked to pericardial patches using EDC/NHS chemistry and could deliver at least 360 ng rapamycin per patch without detectable rapamycin in serum; nanoparticles were detectable in the liver, kidney and spleen but no other sites within 24 hours. In a rat venous patch angioplasty model, control patches developed robust neointimal hyperplasia on the patch luminal surface characterized by Eph-B4-positive endothelium and underlying SMC and infiltrating cells such as macrophages and leukocytes. Patches delivering rapamycin developed less neointimal hyperplasia, less smooth muscle cell proliferation, and had fewer infiltrating cells but retained endothelialization. NP covalently linked to pericardial patches are a novel composite delivery system that allows sustained site-specific delivery of therapeutics; NP delivering rapamycin inhibit patch neointimal hyperplasia. NP linked to patches may represent a next generation of tissue engineered cardiovascular implants.

  4. Convergence of Ubiquitylation and Phosphorylation Signaling in Rapamycin-Treated Yeast Cells

    DEFF Research Database (Denmark)

    Iesmantavicius, Vytautas; Weinert, Brian Tate; Choudhary, Chuna Ram

    2014-01-01

    for reduced ubiquitylation and reduced protein abundance. The convergence of multiple proteome-level changes on the Rsp5 system indicates a key role of this pathway in the response to rapamycin treatment. Collectively, these data reveal new insights into the global proteome dynamics in response to rapamycin...... treatment and provide a first detailed view of the co-regulation of phosphorylation and ubiquitylation-dependent signaling networks by this compound......., and vesicle trafficking. TOR regulates cellular physiology by modulating phosphorylation and ubiquitylation signaling networks, however, the global scope of such regulation is not fully known. Here, we used mass spectrometry (MS)-based proteomics approach for the parallel quantification of ubiquitylation...

  5. Inhibition of Mammalian Target of Rapamycin Signaling with Rapamycin Prevents Trauma-Induced Heterotopic Ossification.

    Science.gov (United States)

    Qureshi, Ammar T; Dey, Devaveena; Sanders, Erin M; Seavey, Jonathan G; Tomasino, Allison M; Moss, Kaitlyn; Wheatley, Benjamin; Cholok, David; Loder, Shawn; Li, John; Levi, Benjamin; Davis, Thomas A

    2017-11-01

    A pressing clinical need exists for 63% to 65% of combat-wounded service members and 11% to 20% of civilians who develop heterotopic ossification (HO) after blast-related extremity injury and traumatic injuries, respectively. The mammalian target of rapamycin pathway is a central cellular sensor of injury. We evaluated the prophylactic effects of rapamycin, a selective inhibitor of mammalian target of rapamycin signaling, on HO formation in a rat model of blast-related, polytraumatic extremity injury. Rapamycin was administered intraperitoneally daily for 14 days at 0.5 mg/kg or 2.5 mg/kg. Ectopic bone formation was monitored by micro-computed tomography and confirmed by histologic examination. Connective tissue progenitor cells, platelet-derived growth factor receptor-α-positive cells, and α-smooth muscle actin-positive blood vessels were assayed at postoperative day 7 by colony formation and immunofluorescence. Early gene expression changes were determined by low-density microarray. There was significant attenuation of 1) total new bone and soft tissue ectopic bone with 0.5 mg/kg (38.5% and 14.7%) and 2.5 mg/kg rapamycin (90.3% and 82.9%), respectively, 2) connective tissue progenitor cells, 3) platelet-derived growth factor receptor-α-positive cells, 4) α-smooth muscle actin-positive blood vessels, and 5) of key extracellular matrix remodeling (CD44, Col1a1, integrins), osteogenesis (Sp7, Runx2, Bmp2), inflammation (Cxcl5, 10, IL6, Ccl2), and angiogenesis (Angpt2) genes. No wound healing complications were noted. Our data demonstrate the efficacy of rapamycin in inhibiting blast trauma-induced HO by a multipronged mechanism. Copyright © 2017 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  6. Synthesis of I-125 labeled photoaffinity rapamycin analogs

    Energy Technology Data Exchange (ETDEWEB)

    Shu, A.Y.L.; Yamashita, D.S.; Holt, D.A.; Heys, J.R. [SmithKline Beecham Pharmaceuticals, King of Prussia, PA (United States)

    1996-03-01

    Two no-carrier-added {sup 125}I-labelled photoaffinity rapamycin analogs were prepared: 7-demethoxy-7-(4-azido-3-{sup 125}I-benzyloxy) rapamycin and its C{sub 28}-C{sub 29} seco analog. The key reactions of the synthesis were substitution of the C{sub 7} methoxyl of rapamycin with 4-azido-3-tributylstannylbenzyloxy group, exchange of tributyltin with {sup 125}I using Na{sup 125}I and Chloramine-T, and a ZnCl{sub 2} mediated retro-Aldol cleavage of the C{sub 28}-C{sub 29} bond of rapamycin. (author).

  7. Chronic rapamycin treatment causes diabetes in male mice

    National Research Council Canada - National Science Library

    Schindler, Christine E; Partap, Uttara; Patchen, Bonnie K; Swoap, Steven J

    2014-01-01

    .... We observed that treatment with rapamycin for 52 wk induced diabetes in male mice, characterized by hyperglycemia, significant urine glucose levels, and severe glucose and pyruvate intolerance...

  8. Mixing and matching TREK/TRAAK subunits generate heterodimeric K2P channels with unique properties.

    Science.gov (United States)

    Blin, Sandy; Ben Soussia, Ismail; Kim, Eun-Jin; Brau, Frédéric; Kang, Dawon; Lesage, Florian; Bichet, Delphine

    2016-04-12

    The tandem of pore domain in a weak inwardly rectifying K(+) channel (Twik)-related acid-arachidonic activated K(+) channel (TRAAK) and Twik-related K(+) channels (TREK) 1 and TREK2 are active as homodimers gated by stretch, fatty acids, pH, and G protein-coupled receptors. These two-pore domain potassium (K2P) channels are broadly expressed in the nervous system where they control excitability. TREK/TRAAK KO mice display altered phenotypes related to nociception, neuroprotection afforded by polyunsaturated fatty acids, learning and memory, mood control, and sensitivity to general anesthetics. These channels have emerged as promising targets for the development of new classes of anesthetics, analgesics, antidepressants, neuroprotective agents, and drugs against addiction. Here, we show that the TREK1, TREK2, and TRAAK subunits assemble and form active heterodimeric channels with electrophysiological, regulatory, and pharmacological properties different from those of homodimeric channels. Heteromerization occurs between all TREK variants produced by alternative splicing and alternative translation initiation. These results unveil a previously unexpected diversity of K2P channels that will be challenging to analyze in vivo, but which opens new perspectives for the development of clinically relevant drugs.

  9. Therapeutic effects of rapamycin on alcoholic cardiomyopathy.

    Science.gov (United States)

    Tu, Xilin; Wang, Chao; Ru, Xiaoxue; Jing, Lili; Zhou, Lijun; Jing, Ling

    2017-10-01

    The present study aimed to investigate whether rapamycin has therapeutic potential as a treatment for alcoholic cardiomyopathy. Rats were divided into eight groups (n=7 in each group): The control group; the alcohol group; abstinence in the first week; abstinence in the third week; abstinence in the fourth week; abstinent+rapamycin (AB-RAP) until the first week (AB-RAP 1); AB-RAP until the third week (AB-RAP 3); and AB-RAP until the fourth week (AB-RAP 4). Subsequently, echocardiography, and hematoxylin-eosin and Masson's staining were performed, followed by electron microscopy and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay. Finally, expression levels of B cell lymphoma-2, Beclin-1 and microtubule-associated protein 1A/1B-light chain 3 were detected by immunohistochemistry and western blot analysis. The levels of left ventricular end-diastolic dimension in AB-RAP 3 (7.00±0.41) and AB-RAP 4 (6.33±0.68) groups were significantly lower when compared with the alcohol group (8.01±0.30; P<0.05). Compared with the alcohol group, the apoptosis rate of left ventricular myocardial tissue in the AB+RAP 3 (37.68±2.15) and AB+RAP 4 (26.97±2.11) groups was significantly reduced (P<0.05). To conclude, rapamycin may be considered as a therapeutic tool to attenuate alcoholic cardiomyopathy and improve cardiac function through increasing autophagy and reducing apoptosis.

  10. Mammalian Target of Rapamycin Inhibition With Rapamycin Mitigates Radiation-Induced Pulmonary Fibrosis in a Murine Model

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Eun Joo [Radiation Oncology Branch, Center for Cancer Research, National Institutes of Health, Bethesda, Maryland (United States); Sowers, Anastasia; Thetford, Angela [Radiation Biology Branch, Center for Cancer Research, National Institutes of Health, Bethesda, Maryland (United States); McKay-Corkum, Grace; Chung, Su I. [Radiation Oncology Branch, Center for Cancer Research, National Institutes of Health, Bethesda, Maryland (United States); Mitchell, James B. [Radiation Biology Branch, Center for Cancer Research, National Institutes of Health, Bethesda, Maryland (United States); Citrin, Deborah E., E-mail: citrind@mail.nih.gov [Radiation Oncology Branch, Center for Cancer Research, National Institutes of Health, Bethesda, Maryland (United States)

    2016-11-15

    Purpose: Radiation-induced pulmonary fibrosis (RIPF) is a late toxicity of therapeutic radiation. Signaling of the mammalian target of rapamycin drives several processes implicated in RIPF, including inflammatory cytokine production, fibroblast proliferation, and epithelial senescence. We sought to determine if mammalian target of rapamycin inhibition with rapamycin would mitigate RIPF. Methods and Materials: C57BL/6NCr mice received a diet formulated with rapamycin (14 mg/kg food) or a control diet 2 days before and continuing for 16 weeks after exposure to 5 daily fractions of 6 Gy of thoracic irradiation. Fibrosis was assessed with Masson trichrome staining and hydroxyproline assay. Cytokine expression was evaluated by quantitative real-time polymerase chain reaction. Senescence was assessed by staining for β-galactosidase activity. Results: Administration of rapamycin extended the median survival of irradiated mice compared with the control diet from 116 days to 156 days (P=.006, log-rank test). Treatment with rapamycin reduced hydroxyproline content compared with the control diet (irradiation plus vehicle, 45.9 ± 11.8 μg per lung; irradiation plus rapamycin, 21.4 ± 6.0 μg per lung; P=.001) and reduced visible fibrotic foci. Rapamycin treatment attenuated interleukin 1β and transforming growth factor β induction in irradiated lungs compared with the control diet. Type II pneumocyte senescence after irradiation was reduced with rapamycin treatment at 16 weeks (3-fold reduction at 16 weeks, P<.001). Conclusions: Rapamycin protected against RIPF in a murine model. Rapamycin treatment reduced inflammatory cytokine expression, extracellular matrix production, and senescence in type II pneumocytes.

  11. Rapamycin inhibits poly(ADP-ribosyl)ation in intact cells

    Energy Technology Data Exchange (ETDEWEB)

    Fahrer, Joerg, E-mail: joerg.fahrer@uni-ulm.de [Molecular Toxicology Group, Department of Biology, University of Konstanz (Germany); Wagner, Silvia [Clinic of General, Visceral- and Transplantation Surgery, ZMF, University Hospital Tuebingen (Germany); Buerkle, Alexander [Molecular Toxicology Group, Department of Biology, University of Konstanz (Germany); Koenigsrainer, Alfred [Clinic of General, Visceral- and Transplantation Surgery, ZMF, University Hospital Tuebingen (Germany)

    2009-08-14

    Rapamycin is an immunosuppressive drug, which inhibits the mammalian target of rapamycin (mTOR) kinase activity inducing changes in cell proliferation. Synthesis of poly(ADP-ribose) (PAR) is an immediate cellular response to genotoxic stress catalyzed mostly by poly(ADP-ribose) polymerase 1 (PARP-1), which is also controlled by signaling pathways. Therefore, we investigated whether rapamycin affects PAR production. Strikingly, rapamycin inhibited PAR synthesis in living fibroblasts in a dose-dependent manner as monitored by immunofluorescence. PARP-1 activity was then assayed in vitro, revealing that down-regulation of cellular PAR production by rapamycin was apparently not due to competitive PARP-1 inhibition. Further studies showed that rapamycin did not influence the cellular NAD pool and the activation of PARP-1 in extracts of pretreated fibroblasts. Collectively, our data suggest that inhibition of cellular PAR synthesis by rapamycin is mediated by formation of a detergent-sensitive complex in living cells, and that rapamycin may have a potential as therapeutic PARP inhibitor.

  12. Rapamycin extends murine lifespan but has limited effects on aging.

    Science.gov (United States)

    Neff, Frauke; Flores-Dominguez, Diana; Ryan, Devon P; Horsch, Marion; Schröder, Susanne; Adler, Thure; Afonso, Luciana Caminha; Aguilar-Pimentel, Juan Antonio; Becker, Lore; Garrett, Lillian; Hans, Wolfgang; Hettich, Moritz M; Holtmeier, Richard; Hölter, Sabine M; Moreth, Kristin; Prehn, Cornelia; Puk, Oliver; Rácz, Ildikó; Rathkolb, Birgit; Rozman, Jan; Naton, Beatrix; Ordemann, Rainer; Adamski, Jerzy; Beckers, Johannes; Bekeredjian, Raffi; Busch, Dirk H; Ehninger, Gerhard; Graw, Jochen; Höfler, Heinz; Klingenspor, Martin; Klopstock, Thomas; Ollert, Markus; Stypmann, Jörg; Wolf, Eckhard; Wurst, Wolfgang; Zimmer, Andreas; Fuchs, Helmut; Gailus-Durner, Valérie; Hrabe de Angelis, Martin; Ehninger, Dan

    2013-08-01

    Aging is a major risk factor for a large number of disorders and functional impairments. Therapeutic targeting of the aging process may therefore represent an innovative strategy in the quest for novel and broadly effective treatments against age-related diseases. The recent report of lifespan extension in mice treated with the FDA-approved mTOR inhibitor rapamycin represented the first demonstration of pharmacological extension of maximal lifespan in mammals. Longevity effects of rapamycin may, however, be due to rapamycin's effects on specific life-limiting pathologies, such as cancers, and it remains unclear if this compound actually slows the rate of aging in mammals. Here, we present results from a comprehensive, large-scale assessment of a wide range of structural and functional aging phenotypes, which we performed to determine whether rapamycin slows the rate of aging in male C57BL/6J mice. While rapamycin did extend lifespan, it ameliorated few studied aging phenotypes. A subset of aging traits appeared to be rescued by rapamycin. Rapamycin, however, had similar effects on many of these traits in young animals, indicating that these effects were not due to a modulation of aging, but rather related to aging-independent drug effects. Therefore, our data largely dissociate rapamycin's longevity effects from effects on aging itself.

  13. Synergistic Effect of Rapamycin and Metformin Against Age-Dependent Oxidative Stress in Rat Erythrocytes.

    Science.gov (United States)

    Singh, Abhishek Kumar; Garg, Geetika; Singh, Sandeep; Rizvi, Syed Ibrahim

    2017-10-01

    Erythrocytes are particularly vulnerable toward age-dependent oxidative stress-mediated damage. Caloric restriction mimetics (CRMs) may provide a novel strategy for the maintenance of redox balance as well as effective treatment of age-associated diseases. Herein, we have investigated the beneficial effect of cotreatment with CRM-candidate drugs, rapamycin (an immunosuppressant drug and inhibitor of mammalian target of rapamycin) and metformin (an antidiabetic biguanide and activator of adenosine monophosphate kinase), against aging-induced oxidative stress in erythrocytes and plasma of aging rats. Male Wistar rats of age 4 (young) and 24 months (old) were coexposed to rapamycin (0.5 mg/kg body weight [b.w.]) and metformin (300 mg/kg b.w.), and data were compared with the response of rats receiving an independent exposure to these chemicals at similar doses. The exposure of individual candidate drugs significantly reversed the age-dependent alterations in the endpoints associated with oxidative stress such as reactive oxygen species, ferric reducing ability of plasma, malondialdehyde, reduced glutathione, plasma membrane redox system, plasma protein carbonyl, and acetyl cholinesterase in erythrocytes and plasma of aging rats. However, the cotreatment with rapamycin and metformin showed a significant augmented effect compared with individual drug interventions on reversal of these age-dependent biomarkers of oxidative stress, suggesting a synergistic response. Thus, the findings open up further possibilities for the design of new combinatorial therapies to prevent oxidative stress- and age-associated health problems.

  14. Myxoma virus virotherapy for glioma in immunocompetent animal models: optimizing administration routes and synergy with rapamycin.

    Science.gov (United States)

    Lun, XueQing; Alain, Tommy; Zemp, Franz J; Zhou, Hongyuan; Rahman, Masmudur M; Hamilton, Mark G; McFadden, Grant; Bell, John; Senger, Donna L; Forsyth, Peter A

    2010-01-15

    Oncolytic myxoma virus (MYXV) is being developed as a novel virotherapeutic against human brain cancer and has promising activity against human brain tumor models in immunocompromised hosts. Because an intact immune system could reduce its efficacy, the purpose of this study was to evaluate the oncolytic potential of MYXV in immunocompetent racine glioma models. Here, we report that MYXV infects and kills all racine cell glioma lines and that its effects are enhanced by rapamycin. Intratumoral administration of MYXV with rapamycin improved viral replication in the tumor and significantly prolonged host survival. Similarly, coadministration via a method of convection-enhanced delivery (CED) enhanced viral replication and efficacy in vivo. Mechanisms by which rapamycin improved MYXV oncolysis included an inhibition of type I IFN production in vitro and a reduction of intratumoral infiltration of CD68(+) microglia/macrophages and CD163(+) macrophages in vivo. Our findings define a method to improve MYXV efficacy against gliomas by rapamycin coadministration, which acts to promote immune responses engaged by viral delivery.

  15. Surface engineering of porous silicon microparticles for intravitreal sustained delivery of rapamycin.

    Science.gov (United States)

    Nieto, Alejandra; Hou, Huiyuan; Moon, Sang Woong; Sailor, Michael J; Freeman, William R; Cheng, Lingyun

    2015-01-22

    To understand the relationship between rapamycin loading/release and surface chemistries of porous silicon (pSi) to optimize pSi-based intravitreal delivery system. Three types of surface chemical modifications were studied: (1) pSi-COOH, containing 10-carbon aliphatic chains with terminal carboxyl groups grafted via hydrosilylation of undecylenic acid; (2) pSi-C12, containing 12-carbon aliphatic chains grafted via hydrosilylation of 1-dodecene; and (3) pSiO2-C8, prepared by mild oxidation of the pSi particles followed by grafting of 8-hydrocarbon chains to the resulting porous silica surface via a silanization. The efficiency of rapamycin loading follows the order (micrograms of drug/milligrams of carrier): pSiO2-C8 (105 ± 18) > pSi-COOH (68 ± 8) > pSi-C12 (36 ± 6). Powder X-ray diffraction data showed that loaded rapamycin was amorphous and dynamic drug-release study showed that the availability of the free drug was increased by 6-fold (compared with crystalline rapamycin) by using pSiO2-C8 formulation (P = 0.0039). Of the three formulations in this study, pSiO2-C8-RAP showed optimal performance in terms of simultaneous release of the active drug and carrier degradation, and drug-loading capacity. Released rapamycin was confirmed with the fingerprints of the mass spectrometry and biologically functional as the control of commercial crystalline rapamycin. Single intravitreal injections of 2.9 ± 0.37 mg pSiO2-C8-RAP into rabbit eyes resulted in more than 8 weeks of residence in the vitreous while maintaining clear optical media and normal histology of the retina in comparison to the controls. Porous silicon-based rapamycin delivery system using the pSiO2-C8 formulation demonstrated good ocular compatibility and may provide sustained drug release for retina. Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc.

  16. Rapamycin Synergizes with Cisplatin in Antiendometrial Cancer Activation by Improving IL-27–Stimulated Cytotoxicity of NK Cells

    Directory of Open Access Journals (Sweden)

    Wen-Jie Zhou

    2018-01-01

    Full Text Available Natural killer (NK cell function is critical for controlling initial tumor growth and determining chemosensitivity of the tumor. A synergistic relationship between rapamycin and cisplatin in uterine endometrial cancer (UEC in vitro has been reported, but the mechanism and the combined therapeutic strategy for endometrial cancer (EC are still unknown. We found a positive correlation between the level of IL-27 and the differentiated stage of UEC. The increase of IL-27 in uterine endometrial cancer cell (UECC lines (Ishikawa, RL95-2 and KLE led to a high cytotoxic activity of NK cells to UECC in the co-culture system. Exposure with rapamycin enhanced the cytotoxicity of NK cells by upregulating the expression of IL-27 in UECC and IL-27 receptors (IL-27Rs: WSX-1 and gp130 on NK cells and further restricted the growth of UEC in Ishikawa-xenografted nude mice. In addition, treatment with rapamycin resulted in an increased autophagy level of UECC, and IL-27 enhanced this ability of rapamycin. Cisplatin-mediated NK cells' cytotoxic activity and anti-UEC activation were independent of IL-27; however, the combination of rapamycin and cisplatin led to a higher cytotoxic activity of NK cells, smaller UEC volume and longer survival rate in vivo. These results suggest that rapamycin and cisplatin synergistically activate the cytotoxicity of NK cells and inhibit the progression of UEC in both an IL-27–dependent and –independent manner. This provides a scientific basis for potential rapamycin-cisplatin combined therapeutic strategies targeted to UEC, especially for the patients with low differentiated stage or abnormally low level of IL-27.

  17. Rapamycin protects testes against germ cell apoptosis and oxidative stress induced by testicular ischemia-reperfusion.

    Science.gov (United States)

    Ghasemnejad-Berenji, Morteza; Ghazi-Khansari, Mahmoud; Yazdani, Iraj; Saravi, Seyed Soheil Saeedi; Nobakht, Maliheh; Abdollahi, Alireza; Ansari, Javad Mohajer; Ghasemnejad-Berenji, Hojjat; Pashapour, Sarvin; Dehpour, Ahmad Reza

    2017-08-01

    Rapamycin is an immunosuppressant compound with a broad spectrum of pharmaco-logical activities. In recent years, it has been used successfully to decrease ischemia-reperfusion injury in several organ systems. The purpose of the present study was to examine the effect of rapamycin on testicular ischemia-reperfusion injury. Seventy-two adult male Wistar rats were divided into six groups: control (group1), sham-operated (Group2), T/D + DMSO as vehicle group (group3), and groups 4-6; respectively received 0.5, 1, and 1.5 mgkg-1 of rapamycin, IP 30 min before detorsion. Ischemia was achieved by twisting the right testis 720° clockwise for 1 hr. The right testis of 6 animals from each group were excised 4 hr after detorsion for the measurement of lipid peroxidation, caspase-3, and antioxidant enzyme activities. Histopathological changes and germ cell apoptosis were determined by measuring mean of seminiferous tubules diameters (MSTD) and TUNEL test in right testis of 6 animals per group, 24 hr after detorsion. Testicular T/D caused increases in the apoptosis, malondialdehyde (MDA), and caspase-3 levels and decreases in the superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities in ipsilateral testis (P<0.001). The rats treated with rapamycin had significant decreases in the MDA and caspase-3 levels and significant increases in the SOD, CAT and GPx activities in ipsilateral testis compared with the T/D group (P<0.001); germ cell apoptosis was decreased, and MSTD was improved. Rapamycin administration during testicular torsion decreased ischemia/reperfusion (I/R) cellular damage.

  18. Potential use of rapamycin in HIV infection

    DEFF Research Database (Denmark)

    Donia, Marco; McCubrey, James A; Bendtzen, Klaus

    2010-01-01

    The strong need for the development of alternative anti-HIV agents is primarily due to the emergence of strain-resistant viruses, the need for sustained adherence to complex treatment regimens and the toxicity of currently used antiviral drugs. This review analyzes proof of concept studies...... indicating that the immunomodulatory drug rapamycin (RAPA) possesses anti-HIV properties both in vitro and in vivo that qualifies it as a potential new anti-HIV drug. It represents a literature review of published studies that evaluated the in vitro and in vivo activity of RAPA in HIV. RAPA represses HIV-1...... replication in vitro through different mechanisms including, but not limited, to down regulation of CCR5. In addition RAPA synergistically enhances the anti-HIV activity of entry inhibitors such as vicriviroc, aplaviroc and enfuvirtide in vitro. RAPA also inhibits HIV-1 infection in human peripheral blood...

  19. Rapamycin is neuroprotective in a rat chronic hypertensive glaucoma model.

    Directory of Open Access Journals (Sweden)

    Wenru Su

    Full Text Available Glaucoma is a leading cause of irreversible blindness. Injury of retinal ganglion cells (RGCs accounts for visual impairment of glaucoma. Here, we report rapamycin protects RGCs from death in experimental glaucoma model and the underlying mechanisms. Our results showed that treatment with rapamycin dramatically promote RGCs survival in a rat chronic ocular hypertension model. This protective action appears to be attributable to inhibition of neurotoxic mediators release and/or direct suppression of RGC apoptosis. In support of this mechanism, in vitro, rapamycin significantly inhibits the production of NO, TNF-α in BV2 microglials by modulating NF-κB signaling. In experimental animals, treatment with rapamycin also dramatically inhibited the activation of microglials. In primary RGCs, rapamycin was capable of direct suppression the apoptosis of primary RGCs induced by glutamate. Mechanistically, rapamycin-mediated suppression of RGCs apoptosis is by sparing phosphorylation of Akt at a site critical for maintenance of its survival-promoting activity in cell and animal model. These results demonstrate that rapamycin is neuroprotective in experimental glaucoma, possibly via decreasing neurotoxic releasing and suppressing directly apoptosis of RGCs.

  20. Rapamycin suppresses brain aging in senescence-accelerated OXYS rats.

    Science.gov (United States)

    Kolosova, Nataliya G; Vitovtov, Anton O; Muraleva, Natalia A; Akulov, Andrey E; Stefanova, Natalia A; Blagosklonny, Mikhail V

    2013-06-01

    Cellular and organismal aging are driven in part by the MTOR (mechanistic target of rapamycin) pathway and rapamycin extends life span inC elegans, Drosophila and mice. Herein, we investigated effects of rapamycin on brain aging in OXYS rats. Previously we found, in OXYS rats, an early development of age-associated pathological phenotypes similar to several geriatric disorders in humans, including cerebral dysfunctions. Behavioral alterations as well as learning and memory deficits develop by 3 months. Here we show that rapamycin treatment (0.1 or 0.5 mg/kg as a food mixture daily from the age of 1.5 to 3.5 months) decreased anxiety and improved locomotor and exploratory behavior in OXYS rats. In untreated OXYS rats, MRI revealed an increase of the area of hippocampus, substantial hydrocephalus and 2-fold increased area of the lateral ventricles. Rapamycin treatment prevented these abnormalities, erasing the difference between OXYS and Wister rats (used as control). All untreated OXYS rats showed signs of neurodegeneration, manifested by loci of demyelination. Rapamycin decreased the percentage of animals with demyelination and the number of loci. Levels of Tau and phospho-Tau (T181) were increased in OXYS rats (compared with Wistar). Rapamycin significantly decreased Tau and inhibited its phosphorylation in the hippocampus of OXYS and Wistar rats. Importantly, rapamycin treatment caused a compensatory increase in levels of S6 and correspondingly levels of phospo-S6 in the frontal cortex, indicating that some downstream events were compensatory preserved, explaining the lack of toxicity. We conclude that rapamycin in low chronic doses can suppress brain aging.

  1. Rapamycin has a biphasic effect on insulin sensitivity in C2C12 myotubes due to sequential disruption of mTORC1 and mTORC2

    Directory of Open Access Journals (Sweden)

    Lan eYe

    2012-09-01

    Full Text Available Rapamycin, an inhibitor of mTOR complex 1 (mTORC1, improves insulin sensitivity in acute studies in vitro and in vivo by disrupting a negative feedback loop mediated by S6 kinase. We find that rapamycin has a clear biphasic effect on insulin sensitivity in C2C12 myotubes, with enhanced responsiveness during the first hour that declines to almost complete insulin resistance by 24-48 hours. We and others have recently observed that chronic rapamycin treatment induces insulin resistance in rodents, at least in part due to disruption of mTORC2, an mTOR-containing complex that is not acutely sensitive to the drug. Chronic rapamycin treatment may also impair insulin action via the inhibition of mTORC1-dependent mitochondrial biogenesis and activity, which could result in a buildup of lipid intermediates that are known to trigger insulin resistance. We confirmed that rapamycin inhibits expression of PGC-1α, a key mitochondrial transcription factor, and acutely reduces respiration rate in myotubes. However, rapamycin did not stimulate phosphorylation of PKCθ, a central mediator of lipid-induced insulin resistance. Instead, we found dramatic disruption of mTORC2, which coincided with the onset of insulin resistance. Selective inhibition of mTORC1 or mTORC2 by shRNA-mediated knockdown of specific components (Raptor and Rictor, respectively confirmed that mitochondrial effects of rapamycin are mTORC1-dependent, whereas insulin resistance was recapitulated only by knockdown of mTORC2. Thus, mTORC2 disruption, rather than inhibition of mitochondria, causes insulin resistance in rapamycin-treated myotubes, and this system may serve as a useful model to understand the effects of rapamycin on mTOR signaling in vivo.

  2. Rapamycin improves motor function, reduces 4-hydroxynonenal adducted protein in brain, and attenuates synaptic injury in a mouse model of synucleinopathy

    Directory of Open Access Journals (Sweden)

    Xiang Bai

    2015-08-01

    Full Text Available Background: Synucleinopathy is any of a group of age-related neurodegenerative disorders including Parkinson's disease, multiple system atrophy, and dementia with Lewy Bodies, which is characterized by α-synuclein inclusions and parkinsonian motor deficits affecting millions of patients worldwide. But there is no cure at present for synucleinopathy. Rapamycin has been shown to be neuroprotective in several in vitro and in vivo synucleinopathy models. However, there are no reports on the long-term effects of RAPA on motor function or measures of neurodegeneration in models of synucleinopathy. Methods: We determined whether long-term feeding a rapamycin diet (14 ppm in diet; 2.25 mg/kg body weight/day improves motor function in neuronal A53T α-synuclein transgenic mice (TG and explored underlying mechanisms using a variety of behavioral and biochemical approaches. Results: After 24 weeks of treatment, rapamycin improved performance on the forepaw stepping adjustment test, accelerating rotarod and pole test. Rapamycin did not alter A53T α-synuclein content. There was no effect of rapamycin treatment on midbrain or striatal monoamines or their metabolites. Proteins adducted to the lipid peroxidation product 4-hydroxynonenal were decreased in brain regions of both wild-type and TG mice treated with rapamycin. Reduced levels of the presynaptic marker synaptophysin were found in several brain regions of TG mice. Rapamycin attenuated the loss of synaptophysin protein in the affected brain regions. Rapamycin also attenuated the loss of synaptophysin protein and prevented the decrease of neurite length in SH-SY5Y cells treated with 4-hydroxynonenal. Conclusion: Taken together, these data suggest that rapamycin, an FDA approved drug, may prove useful in the treatment of synucleinopathy.

  3. Rapamycin Reduces Seizure Frequency in Tuberous Sclerosis Complex

    Science.gov (United States)

    Muncy, Jennifer; Butler, Ian J.; Koenig, Mary Kay

    2011-01-01

    The authors present a 10-year-old girl with tuberous sclerosis complex who has been receiving rapamycin for 10 months for seizure control. She was started at 0.05 mg/kg/d and titrated to an effective dose of 0.15 mg/kg/d. There was a dramatic reduction in seizure frequency with rapamycin therapy. Further studies are needed to objectively investigate the benefits of rapamycin in tuberous sclerosis complex and to clarify its mechanism of seizure control. PMID:19151365

  4. Rapamycin extends life- and health span because it slows aging.

    Science.gov (United States)

    Blagosklonny, Mikhail V

    2013-08-01

    Making headlines, a thought-provocative paper by Neff, Ehninger and coworkers claims that rapamycin extends life span but has limited effects on aging. How is that possibly possible? And what is aging if not an increase of the probability of death with age. I discuss that the JCI paper actually shows that rapamycin slows aging and also extends lifespan regardless of its direct anti-cancer activities. Aging is, in part, MTOR-driven: a purposeless continuation of developmental growth. Rapamycin affects the same processes in young and old animals: young animals' traits and phenotypes, which continuations become hyperfunctional, harmful and lethal later in life.

  5. Increased expression of (immuno)proteasome subunits during epileptogenesis is attenuated by inhibition of the mammalian target of rapamycin pathway.

    Science.gov (United States)

    Broekaart, Diede W M; van Scheppingen, Jackelien; Geijtenbeek, Karlijne W; Zuidberg, Mark R J; Anink, Jasper J; Baayen, Johannes C; Mühlebner, Angelika; Aronica, Eleonora; Gorter, Jan A; van Vliet, Erwin A

    2017-08-01

    Inhibition of the mammalian target of rapamycin (mTOR) pathway reduces epileptogenesis in various epilepsy models, possibly by inhibition of inflammatory processes, which may include the proteasome system. To study the role of mTOR inhibition in the regulation of the proteasome system, we investigated (immuno)proteasome expression during epileptogenesis, as well as the effects of the mTOR inhibitor rapamycin. The expression of constitutive (β1, β5) and immunoproteasome (β1i, β5i) subunits was investigated during epileptogenesis using immunohistochemistry in the electrical post-status epilepticus (SE) rat model for temporal lobe epilepsy (TLE). The effect of rapamycin was studied on (immuno)proteasome subunit expression in post-SE rats that were treated for 6 weeks. (Immuno)proteasome expression was validated in the brain tissue of patients who had SE or drug-resistant TLE and the effect of rapamycin was studied in primary human astrocyte cultures. In post-SE rats, increased (immuno)proteasome expression was detected throughout epileptogenesis in neurons and astrocytes within the hippocampus and piriform cortex and was most evident in rats that developed a progressive form of epilepsy. Rapamycin-treated post-SE rats had reduced (immuno)proteasome protein expression and a lower number of spontaneous seizures compared to vehicle-treated rats. (Immuno)proteasome expression was also increased in neurons and astrocytes within the human hippocampus after SE and in patients with drug-resistant TLE. In vitro studies using cultured human astrocytes showed that interleukin (IL)-1β-induced (immuno)proteasome gene expression could be attenuated by rapamycin. Because dysregulation of the (immuno)proteasome system is observed before the occurrence of spontaneous seizures in rats, is associated with progression of epilepsy, and can be modulated via the mTOR pathway, it may represent an interesting novel target for drug treatment in epilepsy. Wiley Periodicals, Inc. © 2017

  6. Biphasic Rapamycin Effects in Lymphoma and Carcinoma Treatment.

    Science.gov (United States)

    Liu, Yang; Pandeswara, Srilakshmi; Dao, Vinh; Padrón, Álvaro; Drerup, Justin M; Lao, Shunhua; Liu, Aijie; Hurez, Vincent; Curiel, Tyler J

    2017-01-15

    mTOR drives tumor growth but also supports T-cell function, rendering the applications of mTOR inhibitors complex especially in T-cell malignancies. Here, we studied the effects of the mTOR inhibitor rapamycin in mouse EL4 T-cell lymphoma. Typical pharmacologic rapamycin (1-8 mg/kg) significantly reduced tumor burden via direct suppression of tumor cell proliferation and improved survival in EL4 challenge independent of antitumor immunity. Denileukin diftitox (DD)-mediated depletion of regulatory T cells significantly slowed EL4 growth in vivo in a T-cell-dependent fashion. However, typical rapamycin inhibited T-cell activation and tumor infiltration in vivo and failed to boost DD treatment effects. Low-dose (LD) rapamycin (75 μg/kg) increased potentially beneficial CD44hiCD62L(+) CD8(+) central memory T cells in EL4 challenge, but without clinical benefit. LD rapamycin significantly enhanced DD treatment efficacy, but DD plus LD rapamycin treatment effects were independent of antitumor immunity. Instead, rapamycin upregulated EL4 IL2 receptor in vitro and in vivo, facilitating direct DD tumor cell killing. LD rapamycin augmented DD efficacy against B16 melanoma and a human B-cell lymphoma, but not against human Jurkat T-cell lymphoma or ID8agg ovarian cancer cells. Treatment effects correlated with IL2R expression, but mechanisms in some tumors were not fully defined. Overall, our data define a distinct, biphasic mechanisms of action of mTOR inhibition at doses that are clinically exploitable, including in T-cell lymphomas. Cancer Res; 77(2); 520-31. ©2016 AACR. ©2016 American Association for Cancer Research.

  7. Rapamycin Prolongs the Survival of Corneal Epithelial Cells in Culture

    OpenAIRE

    Sanaz Gidfar; Farnoud Y. Milani; Milani, Behrad Y.; Xiang Shen; Medi Eslani; Ilham Putra; Michael J. Huvard; Hossein Sagha; Djalilian, Ali R.

    2017-01-01

    Rapamycin has previously been shown to have anti-aging effects in cells and organisms. These studies were undertaken to investigate the effects of rapamycin on primary human corneal epithelial cells in vitro. Cell growth and viability were evaluated by bright field microscopy. Cell proliferation and cycle were evaluated by flow cytometry. The expression of differentiation markers was evaluated by quantitative PCR and Western blot. Senescence was evaluated by senescence-associated ?-Galactosid...

  8. Rapamycin promotes β-amyloid production via ADAM-10 inhibition

    Science.gov (United States)

    Zhang, Sheqing; Salemi, Jon; Hou, Huayan; Zhu, Yuyan; Mori, Takashi; Giunta, Brian; Obregon, Demian; Tan, Jun

    2010-01-01

    Rapamycin is a well known immunosuppressant drug for rejection prevention in organ transplantation. Numerous clinical trials using rapamycin analogs, involving both children and adults with various disorders are currently ongoing worldwide. Most recently, rapamycin gained much attention for what appears to be life-span extending properties when administered to mice. The risk for Alzheimer disease (AD) is strongly and positively correlated with advancing age and is characterized by deposition of β-amyloid peptides (Aβ) as senile plaques in the brain. We report that rapamycin (2.5 μM), significantly increases Aβ generation in murine neuron-like cells (N2a) transfected with the human “Swedish” mutant amyloid precursor protein (APP). In concert with these observations, we found rapamycin significantly decreases the neuroprotective amino-terminal APP (amyloid precursor protein) cleavage product, soluble APP-α (sAPP-α) while increasing production of the β-carboxyl-terminal fragment of APP (β-CTF). These cleavage events are associated with decreased activation of a disintegrin and metallopeptidase domain-10 (ADAM-10), an important candidate α-secretase which opposes Aβ generation. To validate these findings in vivo, we intraperitoneal (i.p.) injected Tg2576 Aβ-overproducing transgenic mice with rapamycin (3 mg/kg/day) for 2 weeks. We found increased Aβ levels associated with decreased sAPP-α at an average rapamycin plasma concentration of 169.7 ± 23.5 ng/mL by high performance liquid chromatography (HPLC). These data suggest that although rapamycin may increase the lifespan in some mouse models, it may not decrease the risk for age-associated neurodegenerative disorders such as AD. PMID:20542014

  9. Rapamycin extends murine lifespan but has limited effects on aging

    Science.gov (United States)

    Neff, Frauke; Flores-Dominguez, Diana; Ryan, Devon P.; Horsch, Marion; Schröder, Susanne; Adler, Thure; Afonso, Luciana Caminha; Aguilar-Pimentel, Juan Antonio; Becker, Lore; Garrett, Lillian; Hans, Wolfgang; Hettich, Moritz M.; Holtmeier, Richard; Hölter, Sabine M.; Moreth, Kristin; Prehn, Cornelia; Puk, Oliver; Rácz, Ildikó; Rathkolb, Birgit; Rozman, Jan; Naton, Beatrix; Ordemann, Rainer; Adamski, Jerzy; Beckers, Johannes; Bekeredjian, Raffi; Busch, Dirk H.; Ehninger, Gerhard; Graw, Jochen; Höfler, Heinz; Klingenspor, Martin; Klopstock, Thomas; Ollert, Markus; Stypmann, Jörg; Wolf, Eckhard; Wurst, Wolfgang; Zimmer, Andreas; Fuchs, Helmut; Gailus-Durner, Valérie; Hrabe de Angelis, Martin; Ehninger, Dan

    2013-01-01

    Aging is a major risk factor for a large number of disorders and functional impairments. Therapeutic targeting of the aging process may therefore represent an innovative strategy in the quest for novel and broadly effective treatments against age-related diseases. The recent report of lifespan extension in mice treated with the FDA-approved mTOR inhibitor rapamycin represented the first demonstration of pharmacological extension of maximal lifespan in mammals. Longevity effects of rapamycin may, however, be due to rapamycin’s effects on specific life-limiting pathologies, such as cancers, and it remains unclear if this compound actually slows the rate of aging in mammals. Here, we present results from a comprehensive, large-scale assessment of a wide range of structural and functional aging phenotypes, which we performed to determine whether rapamycin slows the rate of aging in male C57BL/6J mice. While rapamycin did extend lifespan, it ameliorated few studied aging phenotypes. A subset of aging traits appeared to be rescued by rapamycin. Rapamycin, however, had similar effects on many of these traits in young animals, indicating that these effects were not due to a modulation of aging, but rather related to aging-independent drug effects. Therefore, our data largely dissociate rapamycin’s longevity effects from effects on aging itself. PMID:23863708

  10. Multiplex detection of homo- and heterodimerization of g protein-coupled receptors by proximity biotinylation.

    Science.gov (United States)

    Steel, Elisabeth; Murray, Victoria L; Liu, Allen P

    2014-01-01

    Dimerization of G protein-coupled receptors (GPCRs) represents a potential mechanism by which GPCR functions are regulated. Several resonance energy transfer (RET)-based methods have revealed GPCR homo- and heterodimerization. However, interpretation of an increase in FRET efficiency could be attributed to either dimerization/oligomerization events or conformational changes within an already dimerized/oligomerized receptor complex. Furthermore, RET-based methods can only measure pairwise dimerization, and cannot easily achieve multiplex detection. In this study, we applied proximity-based biotinylation for detecting receptor dimerization by utilizing a specific enzyme-substrate pair that are fused to GPCRs. The biotin ligase BirA is fused to CXCR4 and site-specifically biotinylates an acceptor peptide (AP) in the presence of biotin. As a test case for our newly developed assay, we have characterized the homo-dimerization of chemokine receptor CXCR4 and heterodimerization of CXCR4 with CCR2 or CCR5. The degree of biotinylation varies with the amount of GPCR-AP as well as biotinylation time. Using enzyme/substrate receptor pairs and measuring receptor biotinylation, we demonstrate that CXCR4 can homo-dimerize and hetero-dimerize with CCR2 and CCR5. The effect of CXCL12, agonist for CXCR4, was found to decrease surface biotinylation of CXCR4-AP. This effect is due to a combination of CXCR4 endocytosis and stabilization of CXCR4 homodimers. Finally, when CXCR4-AP, CCR2-AP, and CCR5-AP were expressed together, we observed CXCR4-CXCR4 homodimers and CXCR4-CCR2 and CXCR4-CCR5 heterodimers. The newly developed assay opens new opportunity for multiplex detection for GPCR homo- and heterodimerization within the same cellular context.

  11. Multiplex detection of homo- and heterodimerization of g protein-coupled receptors by proximity biotinylation.

    Directory of Open Access Journals (Sweden)

    Elisabeth Steel

    Full Text Available Dimerization of G protein-coupled receptors (GPCRs represents a potential mechanism by which GPCR functions are regulated. Several resonance energy transfer (RET-based methods have revealed GPCR homo- and heterodimerization. However, interpretation of an increase in FRET efficiency could be attributed to either dimerization/oligomerization events or conformational changes within an already dimerized/oligomerized receptor complex. Furthermore, RET-based methods can only measure pairwise dimerization, and cannot easily achieve multiplex detection. In this study, we applied proximity-based biotinylation for detecting receptor dimerization by utilizing a specific enzyme-substrate pair that are fused to GPCRs. The biotin ligase BirA is fused to CXCR4 and site-specifically biotinylates an acceptor peptide (AP in the presence of biotin. As a test case for our newly developed assay, we have characterized the homo-dimerization of chemokine receptor CXCR4 and heterodimerization of CXCR4 with CCR2 or CCR5. The degree of biotinylation varies with the amount of GPCR-AP as well as biotinylation time. Using enzyme/substrate receptor pairs and measuring receptor biotinylation, we demonstrate that CXCR4 can homo-dimerize and hetero-dimerize with CCR2 and CCR5. The effect of CXCL12, agonist for CXCR4, was found to decrease surface biotinylation of CXCR4-AP. This effect is due to a combination of CXCR4 endocytosis and stabilization of CXCR4 homodimers. Finally, when CXCR4-AP, CCR2-AP, and CCR5-AP were expressed together, we observed CXCR4-CXCR4 homodimers and CXCR4-CCR2 and CXCR4-CCR5 heterodimers. The newly developed assay opens new opportunity for multiplex detection for GPCR homo- and heterodimerization within the same cellular context.

  12. Tomato FK506 Binding Protein 12KD (FKBP12 mediates the interaction between rapamycin and Target of Rapamycin (TOR

    Directory of Open Access Journals (Sweden)

    Fangjie Xiong

    2016-11-01

    Full Text Available Target of Rapamycin (TOR signaling is an important regulator in multiple organisms including yeast, plants and animals. However, the TOR signaling in plants is much less understood as compared to that in yeast and animals. TOR kinase can be efficiently suppressed by rapamycin in the presence of functional FK506 Binding Protein 12KD (FKBP12 in yeast and animals. In most examined higher plants rapamycin fails to inhibit TOR kinase due to the non-functional FKBP12. Here we find that tomato plants showed obvious growth inhibition when treated with rapamycin and the inhibitory phenotype is similar to suppression of TOR causing by active-site TOR inhibitors (asTORis such as KU63794, AZD8055 and Torin1. The chemical genetic assays using TOR inhibitors and heterologous expressing SlFKBP12 in Arabidopsis indicated that the TOR signaling is functional in tomato. The protein gel shifting and TOR inhibitors combination assays showed that SlFKBP12 can mediate the interaction between rapamycin and TOR. Furthermore, comparative expression profiling analysis between treatments with rapamycin and KU63794 identified highly overlapped Differentially Expressed Genes (DEGs which are involved in many anabolic and catabolic processes, such as photosynthesis, cell wall restructuring, and senescence in tomato. These observations suggest that SlFFBP12 is functional in tomato. The results provided basic information of TOR signaling in tomato, and also some new insights into how TOR controls plant growth and development through reprogramming the transcription profiles

  13. Activated mammalian target of rapamycin is associated with T regulatory cell insufficiency in nasal polyps

    Directory of Open Access Journals (Sweden)

    Shi Jianbo

    2009-02-01

    Full Text Available Abstract Background Decreased infiltration of Foxp3+ T regulatory cell (Treg is considered to be critical for the Th1/Th2 dysregulation of nasal polyps, while the cellular mechanism underlying Foxp3+ Treg insufficiency is currently not well defined. Methods We attempted to investigate the tissue expression of phosphorylated mammalian target of rapamycin (pmTOR and infiltration of Foxp3+ Tregs in 28 nasal polyps and 16 controls by histological staining. We also evaluated the effects of blocking the mTOR signaling pathway with rapamycin on T cell phenotype selection and Foxp3+CD4+ Tregs expansion in a tissue culture system. Results Significantly increased infiltration of pmTOR+ inflammatory cells and decreased infiltration of Foxp3+CD4+ Tregs into nasal polyps was observed, with an inverse association. In the tissue culture system, we detected significantly elevated Foxp3 expression and IL-10 production, as well as an increased percentage of Foxp3+ Tregs in nasal polyps after blocking the mTOR signaling pathway with rapamycin. Conclusion Here we demonstrate for the first time that the mTOR signaling pathway is associated with Foxp3+ Tregs insufficiency in nasal polyps. Inhibition of the mTOR signaling pathway may be helpful for enhancement of Foxp3+ Treg expansion, as well as modulation of T cell phenotype imbalances in nasal polyps.

  14. Rapamycin drives selection against a pathogenic heteroplasmic mitochondrial DNA mutation.

    Science.gov (United States)

    Dai, Ying; Zheng, Kangni; Clark, Joanne; Swerdlow, Russell H; Pulst, Stefan M; Sutton, James P; Shinobu, Leslie A; Simon, David K

    2014-02-01

    Mitochondrial DNA (mtDNA) mutations cause a variety of mitochondrial disorders for which effective treatments are lacking. Emerging data indicate that selective mitochondrial degradation through autophagy (mitophagy) plays a critical role in mitochondrial quality control. Inhibition of mammalian target of rapamycin (mTOR) kinase activity can activate mitophagy. To test the hypothesis that enhancing mitophagy would drive selection against dysfunctional mitochondria harboring higher levels of mutations, thereby decreasing mutation levels over time, we examined the impact of rapamycin on mutation levels in a human cytoplasmic hybrid (cybrid) cell line expressing a heteroplasmic mtDNA G11778A mutation, the most common cause of Leber's hereditary optic neuropathy. Inhibition of mTORC1/S6 kinase signaling by rapamycin induced colocalization of mitochondria with autophagosomes, and resulted in a striking progressive decrease in levels of the G11778A mutation and partial restoration of ATP levels. Rapamycin-induced upregulation of mitophagy was confirmed by electron microscopic evidence of increased autophagic vacuoles containing mitochondria-like organelles. The decreased mutational burden was not due to rapamycin-induced cell death or mtDNA depletion, as there was no significant difference in cytotoxicity/apoptosis or mtDNA copy number between rapamycin and vehicle-treated cells. These data demonstrate the potential for pharmacological inhibition of mTOR kinase activity to activate mitophagy as a strategy to drive selection against a heteroplasmic mtDNA G11778A mutation and raise the exciting possibility that rapamycin may have therapeutic potential for the treatment of mitochondrial disorders associated with heteroplasmic mtDNA mutations, although further studies are needed to determine if a similar strategy will be effective for other mutations and other cell types.

  15. Rapamycin Inhibits ALDH Activity, Resistance to Oxidative Stress, and Metastatic Potential in Murine Osteosarcoma Cells

    Directory of Open Access Journals (Sweden)

    Xiaodong Mu

    2013-01-01

    Full Text Available Osteosarcoma (OS is the most common primary malignancy of bone. Mortality is determined by the presence of metastatic disease, but little is known regarding the biochemical events that drive metastases. Two murine OS cell lines, K7M2 and K12, are related but differ significantly in their metastatic potentials: K7M2 is highly metastatic whereas K12 displays much less metastatic potential. Using this experimental system, the mammalian target of rapamycin (mTOR pathway has been implicated in OS metastasis. We also discovered that aldehyde dehydrogenase (ALDH, a stem cell marker activity is higher in K7M2 cells than K12 cells. Rapamycin treatment reduces the expression and enzymatic activity of ALDH in K7M2 cells. ALDH inhibition renders these cells more susceptible to apoptotic death when exposed to oxidative stress. Furthermore, rapamycin treatment reduces bone morphogenetic protein-2 (BMP2 and vascular endothelial growth factor (VEGF gene expression and inhibits K7M2 proliferation, migration, and invasion in vitro. Inhibition of ALDH with disulfiram correlated with decreased mTOR expression and activity. In conclusion, we provide evidence for interaction between mTOR activity, ALDH activity, and metastatic potential in murine OS cells. Our work suggests that mTOR and ALDH are therapeutic targets for the treatment and prevention of OS metastasis.

  16. Rapamycin protects testes against germ cell apoptosis and oxidative stress induced by testicular ischemia-reperfusion

    Directory of Open Access Journals (Sweden)

    Morteza Ghasemnejad-berenji

    2017-08-01

    Full Text Available Objective(s:Rapamycin is an immunosuppressant compound with a broad spectrum of pharmaco-logical activities. In recent years, it has been used successfully to decrease ischemia-reperfusion injury in several organ systems. The purpose of the present study was to examine the effect of rapamycin on testicular ischemia-reperfusion injury. Materials and Methods: Seventy-two adult male Wistar rats were divided into six groups: control (group1, sham-operated (Group2, T/D + DMSO as vehicle group (group3, and groups 4–6; respectively received 0.5, 1, and 1.5 mgkg-1 of rapamycin , IP 30 min before detorsion. Ischemia was achieved by twisting the right testis 720o clockwise for 1 hr. The right testis of 6 animals from each group were excised 4 hr after detorsion for the measurement of lipid peroxidation, caspase-3, and antioxidant enzyme activities. Histopathological changes and germ cell apoptosis were determined by measuring mean of seminiferous tubules diameters (MSTD and TUNEL test in right testis of 6 animals per group, 24 hr after detorsion. Results: Testicular T/D caused increases in the apoptosis, malondialdehyde (MDA, and caspase-3 levels and decreases in the superoxide dismutase (SOD, catalase (CAT, and glutathione peroxidase (GPx activities in ipsilateral testis (P

  17. Beneficial role of rapamycin in experimental autoimmune myositis.

    Directory of Open Access Journals (Sweden)

    Nicolas Prevel

    Full Text Available We developed an experimental autoimmune myositis (EAM mouse model of polymyositis where we outlined the role of regulatory T (Treg cells. Rapamycin, this immunosuppressant drug used to prevent rejection in organ transplantation, is known to spare Treg. Our aim was to test the efficacy of rapamycin in vivo in this EAM model and to investigate the effects of the drug on different immune cell sub-populations.EAM is induced by 3 injections of myosin emulsified in CFA. Mice received rapamycin during 25 days starting one day before myosin immunization (preventive treatment, or during 10 days following the last myosin immunization (curative treatment.Under preventive or curative treatment, an increase of muscle strength was observed with a parallel decrease of muscle inflammation, both being well correlated (R(2 = -0.645, p<0.0001. Rapamycin induced a general decrease in muscle of CD4 and CD8 T cells in lymphoid tissues, but spared B cells. Among T cells, the frequency of Treg was increased in rapamycin treated mice in draining lymph nodes (16.9 ± 2.2% vs. 9.3 ± 1.4%, p<0.001, which were mostly activated regulatory T cells (CD62L(lowCD44(high: 58.1 ± 5.78% vs. 33.1 ± 7%, treated vs. untreated, p<0.001. In rapamycin treated mice, inhibition of proliferation (Ki-67(+ is more important in effector T cells compared to Tregs cells (p<0.05. Furthermore, during preventive treatment, rapamycin increased the levels of KLF2 transcript in CD44(low CD62L(high naive T cell and in CD62L(low CD44(high activated T cell.Rapamycin showed efficacy both as curative and preventive treatment in our murine model of experimental myositis, in which it induced an increase of muscle strength with a parallel decrease in muscle inflammation. Rapamycin administration was also associated with a decrease in the frequency of effector T cells, an increase in Tregs, and, when administered as preventive treatment, an upregulation of KFL2 in naive and activated T cells.

  18. Rapamycin Rescues the Poor Developmental Capacity of Aged Porcine Oocytes

    Directory of Open Access Journals (Sweden)

    Seung Eun Lee

    2014-05-01

    Full Text Available Unfertilized oocytes age inevitably after ovulation, which limits their fertilizable life span and embryonic development. Rapamycin affects mammalian target of rapamycin (mTOR expression and cytoskeleton reorganization during oocyte meiotic maturation. The goal of this study was to examine the effects of rapamycin treatment on aged porcine oocytes and their in vitro development. Rapamycin treatment of aged oocytes for 24 h (68 h in vitro maturation [IVM]; 44 h+10 μM rapamycin/24 h, 47.52±5.68 or control oocytes (44 h IVM; 42.14±4.40 significantly increased the development rate and total cell number compared with untreated aged oocytes (68 h IVM, 22.04±5.68 (p<0.05. Rapamycin treatment of aged IVM oocytes for 24 h also rescued aberrant spindle organization and chromosomal misalignment, blocked the decrease in the level of phosphorylated-p44/42 mitogen-activated protein kinase (MAPK, and increased the mRNA expression of cytoplasmic maturation factor genes (MOS, BMP15, GDF9, and CCNB1 compared with untreated, 24 h-aged IVM oocytes (p<0.05. Furthermore, rapamycin treatment of aged oocytes decreased reactive oxygen species (ROS activity and DNA fragmentation (p<0.05, and downregulated the mRNA expression of mTOR compared with control or untreated aged oocytes. By contrast, rapamycin treatment of aged oocytes increased mitochondrial localization (p<0.05 and upregulated the mRNA expression of autophagy (BECN1, ATG7, MAP1LC3B, ATG12, GABARAP, and GABARAPL1, anti-apoptosis (BCL2L1 and BIRC5; p<0.05, and development (NANOG and SOX2; p<0.05 genes, but it did not affect the mRNA expression of pro-apoptosis genes (FAS and CASP3 compared with the control. This study demonstrates that rapamycin treatment can rescue the poor developmental capacity of aged porcine oocytes.

  19. The mTOR inhibitor rapamycin has limited acute anticonvulsant effects in mice.

    Directory of Open Access Journals (Sweden)

    Adam L Hartman

    Full Text Available The mammalian target of rapamycin (mTOR pathway integrates signals from different nutrient sources, including amino acids and glucose. Compounds that inhibit mTOR kinase activity such as rapamycin and everolimus can suppress seizures in some chronic animal models and in patients with tuberous sclerosis. However, it is not known whether mTOR inhibitors exert acute anticonvulsant effects in addition to their longer term antiepileptogenic effects. To gain insights into how rapamycin suppresses seizures, we investigated the anticonvulsant activity of rapamycin using acute seizure tests in mice.Following intraperitoneal injection of rapamycin, normal four-week-old male NIH Swiss mice were evaluated for susceptibility to a battery of acute seizure tests similar to those currently used to screen potential therapeutics by the US NIH Anticonvulsant Screening Program. To assess the short term effects of rapamycin, mice were seizure tested in ≤ 6 hours of a single dose of rapamycin, and for longer term effects of rapamycin, mice were tested after 3 or more daily doses of rapamycin.The only seizure test where short-term rapamycin treatment protected mice was against tonic hindlimb extension in the MES threshold test, though this protection waned with longer rapamycin treatment. Longer term rapamycin treatment protected against kainic acid-induced seizure activity, but only at late times after seizure onset. Rapamycin was not protective in the 6 Hz or PTZ seizure tests after short or longer rapamycin treatment times. In contrast to other metabolism-based therapies that protect in acute seizure tests, rapamycin has limited acute anticonvulsant effects in normal mice.The efficacy of rapamycin as an acute anticonvulsant agent may be limited. Furthermore, the combined pattern of acute seizure test results places rapamycin in a third category distinct from both fasting and the ketogenic diet, and which is more similar to drugs acting on sodium channels.

  20. Split tasks of asymmetric nucleotide-binding sites in the heterodimeric ABC exporter EfrCD.

    Science.gov (United States)

    Hürlimann, Lea M; Hohl, Michael; Seeger, Markus A

    2017-06-01

    Many heterodimeric ATP-binding cassette (ABC) exporters evolved asymmetric ATP-binding sites containing a degenerate site incapable of ATP hydrolysis due to noncanonical substitutions in conserved sequence motifs. Recent studies revealed that nucleotide binding to the degenerate site stabilizes contacts between the nucleotide-binding domains (NBDs) of the inward-facing transporter and regulates ATP hydrolysis at the consensus site via allosteric coupling mediated by the D-loops. However, it is unclear whether nucleotide binding to the degenerate site is strictly required for substrate transport. In this study, we examined the functional consequences of a systematic set of mutations introduced at the degenerate and consensus site of the multidrug efflux pump EfrCD of Enterococcus faecalis. Mutating motifs which differ among the two ATP-binding sites (Walker B, switch loop, and ABC signature) or which are involved in interdomain communication (D-loop and Q-loop) led to asymmetric results in the functional assays and were better tolerated at the degenerate site. This highlights the importance of the degenerate site to allosterically regulate the events at the consensus site. Mutating invariant motifs involved in ATP binding and NBD closure (A-loop and Walker A) resulted in equally reduced transport activities, regardless at which ATP-binding site they were introduced. In contrast to previously investigated heterodimeric ABC exporters, mutation of the degenerate site Walker A lysine completely inactivated ATPase activity and substrate transport, indicating that ATP binding to the degenerate site is essential for EfrCD. This study provides novel insights into the split tasks of asymmetric ATP-binding sites of heterodimeric ABC exporters. © 2017 The Authors. The FEBS Journal published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.

  1. Bone growth during rapamycin therapy in young rats

    Directory of Open Access Journals (Sweden)

    He Yu-Zhu

    2009-01-01

    Full Text Available Abstract Background Rapamycin is an effective immunosuppressant widely used to maintain the renal allograft in pediatric patients. Linear growth may be adversely affected in young children since rapamycin has potent anti-proliferative and anti-angiogenic properties. Methods Weanling three week old rats were given rapamycin at 2.5 mg/kg daily by gavage for 2 or 4 weeks and compared to a Control group given equivalent amount of saline. Morphometric measurements and biochemical determinations for serum calcium, phosphate, iPTH, urea nitrogen, creatinine and insulin-growth factor I (IGF-I were obtained. Histomorphometric analysis of the growth plate cartilage, in-situ hybridization experiments and immunohistochemical studies for various proteins were performed to evaluate for chondrocyte proliferation, chondrocyte differentiation and chondro/osteoclastic resorption. Results At the end of the 2 weeks, body and tibia length measurements were shorter after rapamycin therapy associated with an enlargement of the hypertrophic zone in the growth plate cartilage. There was a decrease in chondrocyte proliferation assessed by histone-4 and mammalian target of rapamycin (mTOR expression. A reduction in parathyroid hormone/parathyroid hormone related peptide (PTH/PTHrP and an increase in Indian hedgehog (Ihh expression may explain in part, the increase number of hypertrophic chondrocytes. The number of TRAP positive multinucleated chondro/osteoclasts declined in the chondro-osseous junction with a decrease in the receptor activator of nuclear factor kappa β ligand (RANKL and vascular endothelial growth factor (VEGF expression. Although body and tibial length remained short after 4 weeks of rapamycin, changes in the expression of chondrocyte proliferation, chondrocyte differentiation and chondro/osteoclastic resorption which were significant after 2 weeks of rapamycin improved at the end of 4 weeks. Conclusion When given to young rats, 2 weeks of rapamycin

  2. Mammalian target of rapamycin activity is required for expansion of CD34(+) hematopoietic progenitor cells

    NARCIS (Netherlands)

    Geest, Christian R.; Zwartkruis, Fried J.; Vellenga, Edo; Coffer, Paul J.; Buitenhuis, Miranda

    Background The mammalian target of rapamycin is a conserved protein kinase known to regulate protein synthesis, cell size and proliferation. Aberrant regulation of mammalian target of rapamycin activity has been observed in hematopoietic malignancies, including acute leukemias and myelodysplastic

  3. Mammalian target of rapamycin activity is required for expansion of CD34+ hematopoietic progenitor cells

    NARCIS (Netherlands)

    Geest, C.R.; Zwartkruis, G.J.T.; Vellenga, E.; Coffer, P.J.; Buitenhuis, M.

    2009-01-01

    Background The mammalian target of rapamycin is a conserved protein kinase known to regulate protein synthesis, cell size and proliferation. Aberrant regulation of mammalian target of rapamycin activity has been observed in hematopoietic malignancies, including acute leukemias and

  4. The effect of rapamycin on biodiesel-producing protist Euglena gracilis.

    Science.gov (United States)

    Mukaida, Shiho; Ogawa, Takumi; Ohishi, Kazuko; Tanizawa, Yasuhiro; Ohta, Daisaku; Arita, Masanori

    2016-06-01

    Rapamycin induces autophagy with lipid remodeling in yeast and mammalian cells. To investigate the lipid biosynthesis of Euglena gracilis, rapamycin was supplemented in comparison with two model algae, Chlamydomonas reinhardtii and Cyanidioschyzon merolae. In Euglena, rapamycin induced the reduction of chlorophylls and the accumulation of neutral lipids without deterring its cell proliferation. Its lipidomic profile revealed that the fatty acid composition did not alter by supplementing rapamycin. In Chlamydomonas, however, rapamycin induced serious growth inhibition as reported elsewhere. With a lower concentration of rapamycin, the alga accumulated neutral lipids without reducing chlorophylls. In Cyanidioschyzon, rapamycin did not increase neutral lipids but reduced its chlorophyll content. We also tested fatty acid elongase inhibitors such as pyroxasulfone or flufenacet in Euglena with no significant change in its neutral lipid contents. In summary, controlled supplementation of rapamycin can increase the yield of neutral lipids while the scheme is not always applicable for other algal species.

  5. Disruption of mammalian target of rapamycin complex 1 in macrophages decreases chemokine gene expression and atherosclerosis

    NARCIS (Netherlands)

    Ai, Ding; Jiang, Hongfeng; Westerterp, Marit; Murphy, Andrew J.; Wang, Mi; Ganda, Anjali; Abramowicz, Sandra; Welch, Carrie; Almazan, Felicidad; Zhu, Yi; Miller, Yury I.; Tall, Alan R.

    2014-01-01

    The mammalian target of rapamycin complex 1 inhibitor, rapamycin, has been shown to decrease atherosclerosis, even while increasing plasma low-density lipoprotein levels. This suggests an antiatherogenic effect possibly mediated by the modulation of inflammatory responses in atherosclerotic plaques.

  6. Rapamycin inhibits spermatogenesis by changing the autophagy status through suppressing mechanistic target of rapamycin-p70S6 kinase in male rats.

    Science.gov (United States)

    Liu, Shangjing; Huang, Longxian; Geng, Yanqing; He, Junlin; Chen, Xuemei; Xu, Hao; Li, Rong; Wang, Yingxiong; Ding, Yubin; Liu, Xueqing

    2017-10-01

    Rapamycin (sirolimus) is an antiproliferative drug that has been widely used in the clinic as an immunosuppressant and a potential anticancer agent. Certain reports have indicated that rapamycin may induce male infertility through impairing sperm quality. The present study investigated the mechanism of male infertility caused by rapamycin and examined whether withdrawal of rapamycin could recover the number of sperm in rats. Male Sprague‑Dawley rats (n=100) were divided randomly into 5 groups: 3 rapamycin‑treated groups (2, 4 and 6 mg/kg) and 2 control groups [Blank and dimethyl sulfoxide (DMSO)]. Organ coefficients of the testes, number of sperm and hematoxylin‑eosin staining analyses demonstrated that rapamycin treatment markedly damaged the structure of the seminiferous tubule and reduced the number of sperm. Immunohistochemistry of mechanistic target of rapamycin (mTOR) and Ki67 in testes tissue, and western blotting of phosphorylated‑p70S6K and p70S6K, supported the hypothesis that rapamycin causes sperm reduction through inhibiting proliferation of spermatogonia. Unfortunately, 24 weeks after cessation of rapamycin treatment, only the number of sperm in 2 mg/kg group was restored back to the normal level. In addition, to the best of our knowledge, the present study was the first to demonstrate that low doses rapamycin leads to activation of autophagy in rat testes. This may be a self‑protective mechanism of the cell in response to external stress. Thus, spermatogenesis can be recovered in the testes from rats in the low dose group. High doses of rapamycin resulted in excessive consumption of autophagy proteins, and the damage could not be compensated. In addition, it was revealed that cell apoptosis increased after treatment with rapamycin. In conclusion, the present study demonstrated that rapamycin inhibits spermatogenesis through suppressing phosphorylation of p70S6K and changing the autophagy status, ultimately reducing the number of sperm

  7. Inhibition of mammalian target of rapamycin by rapamycin increases the radiosensitivity of esophageal carcinoma Eca109 cells

    OpenAIRE

    ZHANG, DEJUN; XIANG, JIE; GU, YUMING; XU, WEI; XU, HAO; ZU, MAOHENG; PEI, DONGSHENG; ZHENG, JUNNIAN

    2014-01-01

    The aim of the present study was to investigate whether radiation induces the mammalian target of rapamycin (Rap) (mTOR) signaling pathway in esophageal carcinoma Eca109 cells, and whether mTOR inhibition by rapamycin increases Eca109 cell radiosensitivity. Changes in the levels of mTOR signaling pathway and DNA damage-repair proteins in Eca109 cells prior to and following radiation were determined. The Eca109 cells were treated with Rap (0, 100, 200 and 400 nmol/l) in combination with radiat...

  8. Rapamycin treatment causes developmental delay, pigmentation defects, and gastrointestinal malformation on Xenopus embryogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Moriyama, Yuki [Graduate School of Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529 (Japan); Ohata, Yoshihisa [Department of Education (Sciences), Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529 (Japan); Mori, Shoko [Graduate School of Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529 (Japan); Matsukawa, Shinya [Department of Education (Sciences), Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529 (Japan); Michiue, Tatsuo [Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902 (Japan); Asashima, Makoto [Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902 (Japan); Research Center for Stem Cell Engineering, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Baien, Tsukuba, Ibaraki 305-8562 (Japan); Kuroda, Hiroki, E-mail: ehkurod@ipc.shizuoka.ac.jp [Graduate School of Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529 (Japan); Department of Education (Sciences), Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529 (Japan)

    2011-01-28

    Research highlights: {yields} Does famous anti-aging drug rapamycin work from the beginning of life? The answer is yes. {yields} This study shows that developmental speed of frog embryo was dose-dependently decreased by rapamycin treatment. {yields} In additions, morphogenetic effects such as less pigmentations and gut malformation are occurred by rapamycin. -- Abstract: Rapamycin is a drug working as an inhibitor of the TOR (target of rapamycin) signaling pathway and influences various life phenomena such as cell growth, proliferation, and life span extension in eukaryote. However, the extent to which rapamycin controls early developmental events of amphibians remains to be understood. Here we report an examination of rapamycin effects during Xenopus early development, followed by a confirmation of suppression of TOR downstream kinase S6K by rapamycin treatment. First, we found that developmental speed was declined in dose-dependent manner of rapamycin. Second, black pigment spots located at dorsal and lateral skin in tadpoles were reduced by rapamycin treatment. Moreover, in tadpole stages severe gastrointestinal malformations were observed in rapamycin-treated embryos. Taken together with these results, we conclude that treatment of the drug rapamycin causes enormous influences on early developmental period.

  9. Loss of JAK2 regulation via a heterodimeric VHL-SOCS1 E3 ubiquitin ligase underlies Chuvash polycythemia.

    Science.gov (United States)

    Russell, Ryan C; Sufan, Roxana I; Zhou, Bing; Heir, Pardeep; Bunda, Severa; Sybingco, Stephanie S; Greer, Samantha N; Roche, Olga; Heathcote, Samuel A; Chow, Vinca W K; Boba, Lukasz M; Richmond, Terri D; Hickey, Michele M; Barber, Dwayne L; Cheresh, David A; Simon, M Celeste; Irwin, Meredith S; Kim, William Y; Ohh, Michael

    2011-06-19

    Chuvash polycythemia is a rare congenital form of polycythemia caused by homozygous R200W and H191D mutations in the VHL (von Hippel-Lindau) gene, whose gene product is the principal negative regulator of hypoxia-inducible factor. However, the molecular mechanisms underlying some of the hallmark abnormalities of Chuvash polycythemia, such as hypersensitivity to erythropoietin, are unclear. Here we show that VHL directly binds suppressor of cytokine signaling 1 (SOCS1) to form a heterodimeric E3 ligase that targets phosphorylated JAK2 (pJAK2) for ubiquitin-mediated destruction. In contrast, Chuvash polycythemia-associated VHL mutants have altered affinity for SOCS1 and do not engage with and degrade pJAK2. Systemic administration of a highly selective JAK2 inhibitor, TG101209, reversed the disease phenotype in Vhl(R200W/R200W) knock-in mice, an experimental model that recapitulates human Chuvash polycythemia. These results show that VHL is a SOCS1-cooperative negative regulator of JAK2 and provide biochemical and preclinical support for JAK2-targeted therapy in individuals with Chuvash polycythemia.

  10. Novel CH1:CL interfaces that enhance correct light chain pairing in heterodimeric bispecific antibodies.

    Science.gov (United States)

    Bönisch, Maximilian; Sellmann, Carolin; Maresch, Daniel; Halbig, Claudia; Becker, Stefan; Toleikis, Lars; Hock, Björn; Rüker, Florian

    2017-09-01

    Targeting two unique antigens with a single bispecific antibody is an attractive approach with potential broad therapeutic applicability. However, the production of heterodimeric bispecific antibodies (bsAbs) presents a challenge, requiring the co-expression and accurate pairing of two distinct heavy and light chain units. Several undesirable by-products can be formed in the production process, including heavy chain homodimers and non-cognate light chain pairings. Although additional downstream purification methods exist, they are often time consuming and restrict practical large-scale production. In this study, we identify and validate novel Fab interface mutations that increase cognate light chain pairing efficiencies within heterodimeric bsAbs. Importantly, the variable domains remain unaltered as interface mutations were restricted to the CH1 and CL domains. We performed several biochemical assays to demonstrate that the novel engineered interfaces do not adversely impact bispecific antibody expression, stability, affinity and biological function. The designs reported here can easily be applied in a generic manner to use existing antibodies as building blocks for bsAbs which will help to accelerate the identification and production of next generation bispecific antibody therapeutics. © The Author 2017. Published by Oxford University Press.

  11. Mammalian target of rapamycin inhibitor-associated stomatitis

    NARCIS (Netherlands)

    Boers-Doets, Christine B.; Raber-Durlacher, Judith E.; Treister, Nathaniel S.; Epstein, Joel B.; Arends, Anniek B. P.; Wiersma, Diede R.; Lalla, Rajesh V.; Logan, Richard M.; van Erp, Nielka P.; Gelderblom, Hans

    2013-01-01

    With the recent introduction of inhibitors of mammalian target of rapamycin (mTOR) in oncology, distinct cutaneous and oral adverse events have been identified. In fact, stomatitis and rash are documented as the most frequent and potentially dose-limiting side effects. Clinically, mTOR

  12. Suppression of Th17-polarized airway inflammation by rapamycin.

    Science.gov (United States)

    Joean, Oana; Hueber, Anja; Feller, Felix; Jirmo, Adan Chari; Lochner, Matthias; Dittrich, Anna-Maria; Albrecht, Melanie

    2017-11-10

    Because Th17-polarized airway inflammation correlates with poor control in bronchial asthma and is a feature of numerous other difficult-to-treat inflammatory lung diseases, new therapeutic approaches for this type of airway inflammation are necessary. We assessed different licensed anti-inflammatory agents with known or expected efficacy against Th17-polarization in mouse models of Th17-dependent airway inflammation. Upon intravenous transfer of in vitro derived Th17 cells and intranasal challenge with the corresponding antigen, we established acute and chronic murine models of Th17-polarised airway inflammation. Consecutively, we assessed the efficacy of methylprednisolone, roflumilast, azithromycin, AM80 and rapamycin against acute or chronic Th17-dependent airway inflammation. Quantifiers for Th17-associated inflammation comprised: bronchoalveolar lavage (BAL) differential cell counts, allergen-specific cytokine and immunoglobulin secretion, as well as flow cytometric phenotyping of pulmonary inflammatory cells. Only rapamycin proved effective against acute Th17-dependent airway inflammation, accompanied by increased plasmacytoid dendritic cells (pDCs) and reduced neutrophils as well as reduced CXCL-1 levels in BAL. Chronic Th17-dependent airway inflammation was unaltered by rapamycin treatment. None of the other agents showed efficacy in our models. Our results demonstrate that Th17-dependent airway inflammation is difficult to treat with known agents. However, we identify rapamycin as an agent with inhibitory potential against acute Th17-polarized airway inflammation.

  13. Rapamycin prolongs graft survival and induces CD4+IFN-γ+IL-10+ regulatory type 1 cells in old recipient mice.

    Science.gov (United States)

    Quante, Markus; Heinbokel, Timm; Edtinger, Karoline; Minami, Koichiro; Uehara, Hirofumi; Nian, Yeqi; Azuma, Haruhito; Abdi, Reza; Elkhal, Abdallah; Tullius, Stefan G

    2017-08-02

    Although the elderly represents a rapidly growing population among transplant recipients, age-specific aspects have not been considered sufficiently in clinical trials. Moreover, age-specific effects of immunosuppressive therapies remain poorly understood. Here, we assessed the impact of Rapamycin on alloimmune responses in old recipients using a fully MHC-mismatched murine transplantation model. Old untreated recipients displayed a prolonged skin graft survival compared to their young counterparts, an observation that confirmed data of our previous experiments. Rapamycin led to a significant prolongation of graft survival in both, young and old recipients. However, graft survival was age-dependent and extended in old vs. young recipients (19 days vs. 12 days, p=0.004). This age-specific effect was not linked to changes in frequencies or subset composition of either CD8 or CD4 T cells. Moreover, antiproliferative effects of Rapamycin on CD8 and CD4 T cells as assessed by in vivo BrdU-incorporation were comparable and age-independent. In contrast, the systemic production of IL-10 was markedly elevated in old recipients treated with Rapamycin. In parallel to this shift in cytokine balance, IFN-γ/IL-10 double-positive regulatory type 1 cells emerged during Th1-differentiation of old T helper cells in presence of Rapamycin. Similarly, CD4IFN-γIL-10 cells expanded among Foxp3-negative cells after in vivo treatment of old recipients with Rapamycin. Our results highlight novel aspects of age-dependent immunosuppressive effects of Rapamycin, with relevance for age-specific immunosuppressive regimens.

  14. Highly efficient and directional homo- and heterodimeric energy transfer materials based on fluorescently derivatized α,γ-cyclic octapeptides.

    Science.gov (United States)

    Brea, Roberto J; Pérez-Alvite, María Jesús; Panciera, Michele; Mosquera, Manuel; Castedo, Luis; Granja, Juan R

    2011-01-03

    Cyclic octapeptides composed of α-amino acids alternated with cis-3-aminocycloalkanecarboxylic acids, self-assemble as drumlike dimers through β-sheet-like, backbone-to-backbone hydrogen bonding. Heterodimerization appears to be significantly more favored than homodimerization, and this represents a novel approach for the design and fabrication of highly stable heterodimeric assemblies. A multicomponent equilibrium network based on fluorescently derivatized self-assembling α,γ-cyclic octapeptides has been successfully used to form light-harvesting/light-converting ensembles with a distinctive organization of donor and acceptor units able to act as efficient artificial photosystems.

  15. Effects of Cyclosporine, Tacrolimus, and Rapamycin on Osteoblasts.

    Science.gov (United States)

    Martín-Fernández, M; Rubert, M; Montero, M; de la Piedra, C

    2017-11-01

    One factor that can contribute to severe bone loss after transplantation is the direct action of immunosuppressants on bone cells. The aim of this work was to study the effects of cyclosporine (CsA), tacrolimus (FK-506), and rapamycin (RAPA) on the release of three local factors directly implicated in bone-remodeling regulation and apoptosis of human osteoblasts: interleukin (IL)-6, osteoprotegerin, and receptor activator of nuclear factor κβ (RANKL). Human osteoblasts were obtained from five different patients who underwent orthopedic surgery. These cells were treated with what are considered to be a clinically high dose and an acceptable dose of each immunosuppressant-RAPA 50 ng/mL and 12 ng/mL, FK-506 20 ng/mL and 5 ng/mL, CsA 1000 ng/mL and 250 ng/mL-or vehicle. Apoptotic cell death was quantified using flow cytometry of DNA content in permeabilized, propidium iodide-stained cells. IL-6 was measured using enzyme-linked immunosorbent assay (ELISA; Quantikine Human IL6, R&D Systems, Minneapolis, Minn, United States). Messenger RNA (mRNA) expression of osteoprotegerin, RANKL, and IL-6 was measured using quantitative RT-PCR. A significant increase in IL-6 (mRNA and released protein) was observed in the presence of FK-506 and RAPA. Addition of RAPA to the cultures of osteoblasts produced a significant increase in the OPG/RANKL ratio. A significant increase in osteoblast apoptosis was observed in the cells treated with FK-506 and RAPA 24 hours after the addition of immunosuppressants. CsA did not produce any significant changes in osteoblasts. These results suggest that an increase in osteoblast apoptosis by osteoblasts may be one of the mechanisms by which bone loss occurs after RAPA and FK-506 treatments. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. THE EFFECT OF RAPAMYCIN ON SECRETORY ACTIVITY OF THE RABBIT OVARIAN FRAGMENTS

    Directory of Open Access Journals (Sweden)

    Sushmita Nath

    2012-02-01

    Full Text Available The aim of our study was to examine the effect of rapamycin on secretory activity of the rabbit ovarian fragments. The secretion of steroid (progesterone, testosterone, estradiol and peptide (prolactine hormones by ovarian fragments after rapamycin addition at the doses 0, 1, 10, 100 μg.ml-1 was determined. Fragments were incubated with rapamycin for 48 hours. Hormones were determinated by RIA. The experimental data showed that, addition of rapamycin did not affect progesterone and prolactine release (at all doses. Estradiol secretion was inhibited by rapamycin at the doses of 1, 10 and 100 μg.ml-1. Testosterone was inhibited by the rapamycin at the doses of 1 and 10 μg.ml-1 but not at 100 μg.ml-1. In conclusion, our results suggest a direct effect of rapamycin on ovarian functionsand a possible involvement in the regulation of steroidogenesis.

  17. Processing and functional display of the 86 kDa heterodimeric penicillin G acylase on the surface of phage fd

    NARCIS (Netherlands)

    Verhaert, R.M D; van Duin, J; Quax, Wim

    1999-01-01

    The large heterodimeric penicillin G acylase from Alcaligenes faecalis was displayed on the surface of phage fd. We fused the coding sequence (alpha subunit-internal peptide-beta subunit) to the gene of a phage coat protein. A modified g3p signal sequence was used to direct the polypeptide to the

  18. Structure of a post-translationally processed heterodimeric double-headed Kunitz-type serineprotease inhibitor from potato

    NARCIS (Netherlands)

    Meulenbroek, E.M.; Thomassen, E.A.J.; Pouvreau, L.A.M.; Abrahams, J.P.; Gruppen, H.; Pannu, N.S.

    2012-01-01

    Potato serine protease inhibitor (PSPI) constitutes about 22% of the total amount of proteins in potato tubers (cv. Elkana), making it the most abundant protease inhibitor in the plant. PSPI is a heterodimeric double-headed Kunitz-type serine protease inhibitor that can tightly and simultaneously

  19. Rapamycin-Sensitive Late-LTP is Enhanced in the Hippocampus of IL-6 Transgenic Mice.

    Science.gov (United States)

    Olde Engberink, Anneke; Hernandez, Ruben; de Graan, Pierre; Gruol, Donna L

    2017-11-10

    The neuroimmune factor IL-6 has been shown to regulate hippocampal long-term potentiation (LTP), an activity-dependent enhancement of synaptic transmission that plays a central role in memory and learning. This IL-6 action was demonstrated with relatively short IL-6 exposure, and may reflect physiological actions of IL-6. IL-6 is also expressed chronically at elevated levels in the central nervous system (CNS) under pathological conditions such as neurological disorders. Little is known about the effects IL-6 on LTP under such conditions, an issue that we are addressing by electrophysiological recordings from CA1 pyramidal neurons of hippocampal slices from transgenic mice that persistently express elevated levels of IL-6 in the CNS (IL-6 tg). The current studies examined the long-lasting phase of LTP (late LTP; L-LTP) and the potential involvement mammalian target of rapamycin (mTOR), a known regulator of L-LTP and a downstream partner of IL-6 signal transduction pathways. Results show that basal synaptic transmission and L-LTP were increased in hippocampal slices from IL-6 tg mice compared to slices from non-transgenic (non-tg) control mice. An inhibitor of mTOR, rapamycin, reduced L-LTP in slices from both genotypes, and eliminated the difference in magnitude of L-LTP between IL-6 and non-tg hippocampus. There were no genotypic effect of rapamycin on basal synaptic transmission, but synaptic responses during the LTP induction protocol were reduced in IL-6 tg slices, an effect that could contribute to the reduction of L-LTP in the IL-6 tg slices. These results indicate that persistently increased levels of IL-6 can lead to alterations in mTOR regulation of L-LTP, possibly affecting learning and memory. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  20. Mechanistic determinants of the directionality and energetics of active export by a heterodimeric ABC transporter

    Science.gov (United States)

    Grossmann, Nina; Vakkasoglu, Ahmet S.; Hulpke, Sabine; Abele, Rupert; Gaudet, Rachelle; Tampé, Robert

    2014-11-01

    The ATP-binding cassette (ABC) transporter associated with antigen processing (TAP) participates in immune surveillance by moving proteasomal products into the endoplasmic reticulum (ER) lumen for major histocompatibility complex class I loading and cell surface presentation to cytotoxic T cells. Here we delineate the mechanistic basis for antigen translocation. Notably, TAP works as a molecular diode, translocating peptide substrates against the gradient in a strict unidirectional way. We reveal the importance of the D-loop at the dimer interface of the two nucleotide-binding domains (NBDs) in coupling substrate translocation with ATP hydrolysis and defining transport vectoriality. Substitution of the conserved aspartate, which coordinates the ATP-binding site, decreases NBD dimerization affinity and turns the unidirectional primary active pump into a passive bidirectional nucleotide-gated facilitator. Thus, ATP hydrolysis is not required for translocation per se, but is essential for both active and unidirectional transport. Our data provide detailed mechanistic insight into how heterodimeric ABC exporters operate.

  1. Heterodimeric capping protein is required for stereocilia length and width regulation.

    Science.gov (United States)

    Avenarius, Matthew R; Krey, Jocelyn F; Dumont, Rachel A; Morgan, Clive P; Benson, Connor B; Vijayakumar, Sarath; Cunningham, Christopher L; Scheffer, Deborah I; Corey, David P; Müller, Ulrich; Jones, Sherri M; Barr-Gillespie, Peter G

    2017-11-06

    Control of the dimensions of actin-rich processes like filopodia, lamellipodia, microvilli, and stereocilia requires the coordinated activity of many proteins. Each of these actin structures relies on heterodimeric capping protein (CAPZ), which blocks actin polymerization at barbed ends. Because dimension control of the inner ear's stereocilia is particularly precise, we studied the CAPZB subunit in hair cells. CAPZB, present at ∼100 copies per stereocilium, concentrated at stereocilia tips as hair cell development progressed, similar to the CAPZB-interacting protein TWF2. We deleted Capzb specifically in hair cells using Atoh1-Cre, which eliminated auditory and vestibular function. Capzb-null stereocilia initially developed normally but later shortened and disappeared; surprisingly, stereocilia width decreased concomitantly with length. CAPZB2 expressed by in utero electroporation prevented normal elongation of vestibular stereocilia and irregularly widened them. Together, these results suggest that capping protein participates in stereocilia widening by preventing newly elongating actin filaments from depolymerizing. © 2017 Avenarius et al.

  2. Galectin-3 leads to attenuation of apoptosis through Bax heterodimerization in human thyroid carcinoma cells.

    Science.gov (United States)

    Harazono, Yosuke; Kho, Dhong Hyo; Balan, Vitaly; Nakajima, Kosei; Zhang, Tianpeng; Hogan, Victor; Raz, Avraham

    2014-10-30

    Cancer cells survive escaping normal apoptosis and the blocks in apoptosis that keep cancer cells alive are promising candidates for targeted therapy. Galectin-3 (Gal-3) is, a member of the lectin family, which is involved in cell growth, adhesion, proliferation and apoptosis. It remains elusive to understand the role of Gal-3 on apoptosis in thyroid carcinoma cells. Here, we report that Gal-3 heterodimerizes Bax, mediated by the carbohydrate recognition domain (CRD) of Gal-3, leading to anti-apoptotic characteristic. Gal-3/Bax interaction was suppressed by an antagonist of Gal-3, in which in turn cells became sensitive to apoptosis. The data presented here highlight that Gal-3 is involved in the anti-apoptosis of thyroid carcinoma cells. Thus, it suggests that targeting Gal-3 may lead to an improved therapeutic modality for thyroid cancer.

  3. The Heterodimeric ABC Transporter EfrCD Mediates Multidrug Efflux in Enterococcus faecalis

    Science.gov (United States)

    Hürlimann, Lea M.; Corradi, Valentina; Hohl, Michael; Bloemberg, Guido V.; Tieleman, D. Peter

    2016-01-01

    Nosocomial infections with Enterococcus faecalis are an emerging health problem. However, drug efflux pumps contributing to intrinsic drug resistance are poorly studied in this Gram-positive pathogen. In this study, we functionally investigated seven heterodimeric ABC transporters of E. faecalis that are annotated as drug efflux pumps. Deletion of ef0789-ef0790 on the chromosome of E. faecalis resulted in increased susceptibility to daunorubicin, doxorubicin, ethidium, and Hoechst 33342, and the corresponding transporter was named EfrCD. Unexpectedly, the previously described heterodimeric multidrug ABC transporter EfrAB contributes marginally to drug efflux in the endogenous context of E. faecalis. In contrast, heterologous expression in Lactococcus lactis revealed that EfrAB, EfrCD, and the product of ef2226-ef2227 (EfrEF) mediate the efflux of fluorescent substrates and confer resistance to multiple dyes and drugs, including fluoroquinolones. Four of seven transporters failed to exhibit drug efflux activity for the set of drugs and dyes tested, even upon overexpression in L. lactis. Since all seven transporters were purified as heterodimers after overexpression in L. lactis, a lack of drug efflux activity is not attributed to poor expression or protein aggregation. Reconstitution of the purified multidrug transporters EfrAB, EfrCD, and EfrEF in proteoliposomes revealed functional coupling between ATP hydrolysis and drug binding. Our analysis creates an experimental basis for the accurate prediction of drug efflux transporters and indicates that many annotated multidrug efflux pumps might be incapable of drug transport and thus might fulfill other physiological functions in the cell. PMID:27381387

  4. Inhibition of MDM2 Re-Sensitizes Rapamycin Resistant Renal Cancer Cells via the Activation of p53.

    Science.gov (United States)

    Tian, Xin; Dai, Shundong; Sun, Jing; Jiang, Shenyi; Sui, Chengguang; Meng, Fandong; Li, Yan; Fu, Liye; Jiang, Tao; Wang, Yang; Su, Jia; Jiang, Youhong

    2016-01-01

    Rapamycin is a potential anti-cancer agent, which modulates the activity of mTOR, a key regulator of cell growth and proliferation. However, several types of cancer cells are resistant to the anti-proliferative effects of rapamycin. In this study, we report a MDM2/p53-mediated rapamycin resistance in human renal cancer cells. Trypan blue exclusion tests were used to determine the cell viability. Changes in mRNA and protein expression were measured using real-time PCR and western blot, respectively. Xenograft models were established to evaluate the in vivo effects of rapamycin combined with a MDM2 inhibitor. Rapamycin treatment suppresses the expression of MDM2 and exogenous overexpression of MDM2 in A498 cells contributes to rapamycin resistance. By establishing a rapamycin resistant cell line, we observed that MDM2 was significantly upregulated in rapamycin resistant cells than that in rapamycin sensitive cells. Importantly, the rapamycin resistant cells demonstrated attenuated accumulation of p53 in the nucleus in response to rapamycin treatment. Moreover, the inhibition of MDM2 by siMDM2 sensitizes A498 cells to rapamycin through the activation of p53. In both in vitro and in vivo models, the combination of rapamycin with the MDM2 inhibitor, MI-319, demonstrated a synergistic inhibitory effect on rapamycin resistant cells. Our study reports a novel mechanism for rapamycin resistance in human renal cancer and provides a new perspective for the development of anti-cancer drugs. © 2016 S. Karger AG, Basel.

  5. Targeting mTOR with rapamycin: One dose does not fit all

    Science.gov (United States)

    Foster, David A.; Toschi, Alfredo

    2009-01-01

    A puzzling aspect of rapamycin-based therapeutic strategies is the wide disparity in the doses needed to suppress mTOR under different circumstances. A recent study revealing mechanistically how rapamycin suppresses mTOR provides two explanations for the differential sensitivities to rapamycin. First, mTOR exists as two functionally distinct complexes (mTORC1 and mTORC2), and while rapamycin suppresses both, it does so at very different concentrations. Whereas mTORC1 is suppressed by concentrations of rapamycin in the low nM range, mTORC2 generally requires low μM concentrations. Second, the efficacy of rapamycin is dependent on the level of phosphatidic acid (PA), which is required for the assembly of both mTORC1 and mTORC2 complexes. Rapamycin interacts with mTOR in a manner that is competitive with PA. Therefore, elevated levels of PA, which is common in cancer cells, increases the level of rapamycin needed to suppress both mTORC1 and mTORC2. A practical outcome of the recent study is that if PA levels are suppressed, mTORC2 becomes sensitive to concentrations of rapamycin that can be achieved clinically. Since mTORC2 is likely more critical for survival signals in cancer cells, the recent findings suggest new strategies for enhancing the efficacy of rapamycin-based therapeutic approaches in cancer cells. PMID:19270529

  6. Rapamycin causes growth arrest and inhibition of invasion in human chondrosarcoma cells.

    Science.gov (United States)

    Song, Jian; Wang, Xiaobo; Zhu, Jiaxue; Liu, Jun

    2016-01-01

    Chondrosarcoma is a highly malignant tumor that is characterized by a potent capacity to invade locally and cause distant metastasis and notable for its lack of response to conventional chemotherapy or radiotherapy. Rapamycin, the inhibitor of mammalian target of rapamycin (mTOR), is a valuable drug with diverse clinical applications and regulates many cellular processes. However, the effects of rapamycin on cell growth and invasion of human chondrosarcoma cells are not well known. We determined the effect of rapamycin on cell proliferation, cell cycle arrest and invasion by using MTS, flow cytometry and invasion assays in two human chondrosarcoma cell lines, SW1353 and JJ012. Cell cycle regulatory and invasion-related genes' expression analysis was performed by quantitative RT-PCR (qRT-PCR). We also evaluated the effect of rapamycin on tumor growth by using mice xenograph models. Rapamycin significantly inhibited the cell proliferation, induced cell cycle arrest and decreased the invasion ability of human chondrosarcoma cells. Meanwhile, rapamycin modulated the cell cycle regulatory and invasion-related genes' expression. Furthermore, the tumor growth of mice xenograph models with human chondrosarcoma cells was significantly inhibited by rapamycin. These results provided further insight into the role of rapamycin in chondrosarcoma. Therefore, rapamycin targeted therapy may be a potential treatment strategy for chondrosarcoma.

  7. Target of rapamycin signaling orchestrates growth-defense trade-offs in plants.

    Science.gov (United States)

    De Vleesschauwer, David; Filipe, Osvaldo; Hoffman, Gena; Seifi, Hamed Soren; Haeck, Ashley; Canlas, Patrick; Van Bockhaven, Jonas; De Waele, Evelien; Demeestere, Kristof; Ronald, Pamela; Hofte, Monica

    2018-01-01

    Plant defense to microbial pathogens is often accompanied by significant growth inhibition. How plants merge immune system function with normal growth and development is still poorly understood. Here, we investigated the role of target of rapamycin (TOR), an evolutionary conserved serine/threonine kinase, in the plant defense response. We used rice as a model system and applied a combination of chemical, genetic, genomic and cell-based analyses. We demonstrate that ectopic expression of TOR and Raptor (regulatory-associated protein of mTOR), a protein previously demonstrated to interact with TOR in Arabidopsis, positively regulates growth and development in rice. Transcriptome analysis of rice cells treated with the TOR-specific inhibitor rapamycin revealed that TOR not only dictates transcriptional reprogramming of extensive gene sets involved in central and secondary metabolism, cell cycle and transcription, but also suppresses many defense-related genes. TOR overexpression lines displayed increased susceptibility to both bacterial and fungal pathogens, whereas plants with reduced TOR signaling displayed enhanced resistance. Finally, we found that TOR antagonizes the action of the classic defense hormones salicylic acid and jasmonic acid. Together, these results indicate that TOR acts as a molecular switch for the activation of cell proliferation and plant growth at the expense of cellular immunity. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  8. Tumor growth effects of rapamycin on human biliary tract cancer cells

    Directory of Open Access Journals (Sweden)

    Heuer Matthias

    2012-06-01

    Full Text Available Abstract Background Liver transplantation is an important treatment option for patients with liver-originated tumors including biliary tract carcinomas (BTCs. Post-transplant tumor recurrence remains a limiting factor for long-term survival. The mammalian target of rapamycin-targeting immunosuppressive drug rapamycin could be helpful in lowering BTC recurrence rates. Therein, we investigated the antiproliferative effect of rapamycin on BTC cells and compared it with standard immunosuppressants. Methods We investigated two human BTC cell lines. We performed cell cycle and proliferation analyses after treatment with different doses of rapamycin and the standard immunosuppressants, cyclosporine A and tacrolimus. Results Rapamycin inhibited the growth of two BTC cell lines in vitro. By contrast, an increase in cell growth was observed among the cells treated with the standard immunosuppressants. Conclusions These results support the hypothesis that rapamycin inhibits BTC cell proliferation and thus might be the preferred immunosuppressant for patients after a liver transplantation because of BTC.

  9. Rapamycin attenuates bleomycin-induced pulmonary fibrosis in rats and the expression of metalloproteinase-9 and tissue inhibitors of metalloproteinase-1 in lung tissue.

    Science.gov (United States)

    Jin, Xiaoguang; Dai, Huaping; Ding, Ke; Xu, Xuefeng; Pang, Baosen; Wang, Chen

    2014-01-01

    Idiopathic pulmonary fibrosis (IPF) is the most common and devastating form of interstitial lung disease (ILD) in the clinic. There is no effective therapy except for lung transplantation. Rapamycin is an immunosuppressive drug with potent antifibrotic activity. The purpose of this study was to examine the effects of rapamycin on bleomycin-induced pulmonary fibrosis in rats and the relation to the expression of metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1). Sprague-Dawley rats were treated with intratracheal injection of 0.3 ml of bleomycin (5 mg/kg) in sterile 0.9% saline to make the pulmonary fibrosis model. Rapamycin was given at a dose of 0.5 mg/kg per gavage, beginning one day before bleomycin instillation and once daily until animal sacrifice. Ten rats in each group were sacrificed at 3, 7, 14, 28 and 56 days after bleomycin administration. Alveolitis and pulmonary fibrosis were semi-quantitatively assessed after HE staining and Masson staining under an Olympus BX40 microscope with an IDA-2000 Image Analysis System. Type I and III collagen fibers were identified by Picro-sirius-polarization. Hydroxyproline content in lung tissue was quantified by a colorimetric-based spectrophotometric assay, MMP-9 and TIMP-1 were detected by immunohistochemistry and by realtime quantitative reverse transcriptase polymerase chain reaction (RT-PCR). Bleomycin induced alveolitis and pulmonary fibrosis of rats was inhibited by rapamycin. Significant inhibition of alveolitis and hydroxyproline product were demonstrated when daily administration of rapamycin lasted for at least 14 days. The inhibitory efficacy on pulmonary fibrosis was unremarkable until rapamycin treatment lasted for at least 28 days (P pulmonary fibrosis, which is associated with decreased expression of MMP-9 and TIMP-1.

  10. Mesangial Cell Mammalian Target of Rapamycin Complex 1 Activation Results in Mesangial Expansion.

    Science.gov (United States)

    Nagai, Kojiro; Tominaga, Tatsuya; Ueda, Sayo; Shibata, Eriko; Tamaki, Masanori; Matsuura, Motokazu; Kishi, Seiji; Murakami, Taichi; Moriya, Tatsumi; Abe, Hideharu; Doi, Toshio

    2017-10-01

    Human glomerular diseases can be caused by several different diseases, many of which include mesangial expansion and/or proliferation followed by glomerulosclerosis. However, molecular mechanisms underlying the pathologic mesangial changes remain poorly understood. Here, we investigated the role of the mammalian target of rapamycin complex 1 (mTORC1)-S6 kinase pathway in mesangial expansion and/or proliferation by ablating an upstream negative regulator, tuberous sclerosis complex 1 (TSC1), using tamoxifen-induced Foxd1-Cre mice [Foxd1ER(+) TSC1 mice]. Foxd1ER(+) TSC1 mice showed mesangial expansion with increased production of collagen IV, collagen I, and α-smooth muscle actin in glomeruli, but did not exhibit significant mesangial proliferation or albuminuria. Furthermore, rapamycin treatment of Foxd1ER(+) TSC1 mice suppressed mesangial expansion. Among biopsy specimens from patients with glomerular diseases, analysis of phosphorylated ribosomal protein S6 revealed mesangial cell mTORC1 activation in IgA nephropathy and in lupus mesangial proliferative nephritis but not in the early phase of diabetic nephropathy. In summary, mesangial cell mTORC1 activation can cause mesangial expansion and has clinical relevance for human glomerular diseases. This report also confirms that the tamoxifen-induced mesangium-specific Cre-loxP system is useful for studies designed to clarify the role of the mesangium in glomerular diseases in adults. Copyright © 2017 by the American Society of Nephrology.

  11. Chronic exposure to rapamycin and episodic serum starvation modulate ageing of human fibroblasts in vitro.

    Science.gov (United States)

    Sodagam, Lakshman; Lewinska, Anna; Wnuk, Maciej; Rattan, Suresh I S

    2017-10-01

    Mild stress-induced activation of stress response (SR) pathways, such as autophagy, heat shock response, oxidative SR, DNA damage response, and inflammatory response, can be potentially health beneficial. Using the model system of cellular ageing and replicative senescence in vitro, we have studied the ageing modulatory effects of the two conditions, rapamycin and serum starvation. Chronic exposure to 0.1, 1 and 10 nM rapamycin positively modulated the survival, growth, morphology, telomere length, DNA methylation levels, 8-oxo-dG level in DNA, N6-methyl-adenosine level in RNA, and ethanol stress tolerance of serially passaged normal human skin fibroblasts. Furthermore, episodic (once a week) serum starvation of human skin fibroblasts extended their replicative lifespan by about 22%, along with the maintenance of early passage youthful morphology even in late passage cultures. Although the results of this study may be considered preliminary, it can be inferred that intermittent and episodic induction of SR, rather than chronic up-regulation of SR, is more effective and applicable in the practice of hormesis for healthy ageing and longevity.

  12. Autophagy is required for extension of yeast chronological life span by rapamycin

    Science.gov (United States)

    Alvers, Ashley L.; Wood, Michael S.; Hu, Doreen; Kaywell, Amelia C.; Dunn, William A.; Aris, Jhon P.

    2013-01-01

    Rapamycin is an antibiotic that stimulates autophagy in a wide variety of eukaryotes, including the budding yeast Saccharomyces cerevisiae. Low concentrations of rapamycin extend yeast chronological life span (CLS). We have recently shown that autophagy is required for chronological longevity in yeast, which is attributable in part to a role for autophagy in amino acid homeostasis. We report herein that low concentrations of rapamycin stimulate macroautophagy during chronological aging and extend CLS. PMID:19458476

  13. Longitudinal imaging studies of tumor microenvironment in mice treated with the mTOR inhibitor rapamycin.

    Directory of Open Access Journals (Sweden)

    Keita Saito

    Full Text Available Rapamycin is an allosteric inhibitor of mammalian target of rapamycin, and inhibits tumor growth and angiogenesis. Recent studies suggested a possibility that rapamycin renormalizes aberrant tumor vasculature and improves tumor oxygenation. The longitudinal effects of rapamycin on angiogenesis and tumor oxygenation were evaluated in murine squamous cell carcinoma (SCCVII by electron paramagnetic resonance imaging (EPRI and magnetic resonance imaging (MRI to identify an optimal time after rapamycin treatment for enhanced tumor radioresponse. Rapamycin treatment was initiated on SCCVII solid tumors 8 days after implantation (500-750 mm(3 and measurements of tumor pO(2 and blood volume were conducted from day 8 to 14 by EPRI/MRI. Microvessel density was evaluated over the same time period by immunohistochemical analysis. Tumor blood volume as measured by MRI significantly decreased 2 days after rapamycin treatment. Tumor pO(2 levels modestly but significantly increased 2 days after rapamycin treatment; whereas, it decreased in non-treated control tumors. Furthermore, the fraction of hypoxic area (pixels with pO(2<10 mm Hg in the tumor region decreased 2 days after rapamycin treatments. Immunohistochemical analysis of tumor microvessel density and pericyte coverage revealed that microvessel density decreased 2 days after rapamycin treatment, but pericyte coverage did not change, similar to what was seen with anti-angiogenic agents such as sunitinib which cause vascular renormalization. Collectively, EPRI/MRI co-imaging can provide non-invasive evidence of rapamycin-induced vascular renormalization and resultant transient increase in tumor oxygenation. Improved oxygenation by rapamycin treatment provides a temporal window for anti-cancer therapies to realize enhanced response to radiotherapy.

  14. mTORC1 inhibitors rapamycin and metformin affect cardiovascular markers differentially in ZDF rats.

    Science.gov (United States)

    Nistala, Ravi; Raja, Ahmad; Pulakat, Lakshmi

    2017-03-01

    Mammalian target for rapamycin complex 1 (mTORC1) is a common target for the action of immunosuppressant macrolide rapamycin and glucose-lowering metformin. Inhibition of mTORC1 can exert both beneficial and detrimental effects in different pathologies. Here, we investigated the differential effects of rapamycin (1.2 mg/kg per day delivered subcutaneously for 6 weeks) and metformin (300 mg/kg per day delivered orally for 11 weeks) treatments on male Zucker diabetic fatty (ZDF) rats that mimic the cardiorenal pathology of type 2 diabetic patients and progress to insulin insufficiency. Rapamycin and metformin improved proteinuria, and rapamycin also reduced urinary gamma glutamyl transferase (GGT) indicating improvement of tubular health. Metformin reduced food and water intake, and urinary sodium and potassium, whereas rapamycin increased urinary sodium. Metformin reduced plasma alkaline phosphatase, but induced transaminitis as evidenced by significant increases in plasma AST and ALT. Metformin also induced hyperinsulinemia, but did not suppress fasting plasma glucose after ZDF rats reached 17 weeks of age, and worsened lipid profile. Rapamycin also induced mild transaminitis. Additionally, both rapamycin and metformin increased plasma uric acid and creatinine, biomarkers for cardiovascular and renal disease. These observations define how rapamycin and metformin differentially modulate metabolic profiles that regulate cardiorenal pathology in conditions of severe type 2 diabetes.

  15. Health Effects of Long-Term Rapamycin Treatment: The Impact on Mouse Health of Enteric Rapamycin Treatment from Four Months of Age throughout Life.

    Directory of Open Access Journals (Sweden)

    Kathleen E Fischer

    Full Text Available Rapamycin, an mTOR inhibitor, has been shown to extend lifespan in a range of model organisms. It has been reported to extend lifespan in multiple strains of mice, administered chronically or acutely early or late in life. The ability of rapamycin to extend health (healthspan as opposed to life is less well documented. To assess the effects chronic rapamycin treatment on healthspan, enteric rapamycin was given to male and female C57BL/6J mice starting at 4 months of age and continued throughout life. Repeated, longitudinal assessments of health in individual animals were made starting at 16 months of age (=12 months of treatment until death. A number of health parameters were improved (female grip strength, female body mass and reduced sleep fragmentation in both sexes, others showed no significant difference, while at least one (male rotarod performance was negatively affected. Rapamycin treatment affected many measures of health in a highly sex-specific manner. While sex-specific phenotypic effects of rapamycin treatment have been widely reported, in this study we document sex differences in the direction of phenotypic change. Rapamycin-fed males and females were both significantly different from controls; however the differences were in the opposite direction in measures of body mass, percent fat and resting metabolic rate, a pattern not previously reported.

  16. CD9 monoclonal antibody-conjugated PEGylated liposomes for targeted delivery of rapamycin in the treatment of cellular senescence

    Science.gov (United States)

    Thuy Nguyen, Hanh; Thapa, Raj Kumar; Shin, Beom Soo; Jeong, Jee-Heon; Kim, Jae-Ryong; Yong, Chul Soon; Kim, Jong Oh

    2017-03-01

    Premature cellular senescence refers to the state of irreversible cell cycle arrest due to DNA damage or other stresses. In this study, CD9 monoclonal antibody (CD9mAb) was successfully conjugated to the surface of PEGylated liposomes for targeted delivery of rapamycin (LR-CD9mAb) to overcome senescence of CD9 receptor-overexpressing cells. LR-CD9mAb has a small particle size (143.3 ± 2.4 nm), narrow size distribution (polydispersity index: 0.220 ± 0.036), and negative zeta potential (-14.6 ± 1.2 mV). The uptake of CD9-targeted liposomes by premature senescent human dermal fibroblasts (HDFs) was higher than that by young HDFs, as displayed by confocal microscopic images. The senescence might not be reversed by treatment with rapamycin; however, the drug promoted cell proliferation and reduced the number of cells that expressed the senescence-associated-β-galactosidase (SA-β-gal). These effects were further confirmed by cell viability, cell cycle, and Western blotting analyses. Moreover, CD9-targeted liposomes showed better anti-senescence activity, in comparison with free rapamycin or the conventional liposomal formulation, suggesting the potential application of this system in further in vivo studies.

  17. Heterodimerization of ORL1 and Opioid Receptors and Its Consequences for N-type Calcium Channel Regulation*

    OpenAIRE

    Evans, Rhian M; You, Haitao; Hameed, Shahid; Altier, Christophe; Mezghrani, Alexandre; Bourinet, Emmanuel; Zamponi, Gerald W.

    2009-01-01

    We have investigated the heterodimerization of ORL1 receptors and classical members of the opioid receptor family. All three classes of opioid receptors could be co-immunoprecipitated with ORL1 receptors from both transfected tsA-201 cell lysate and rat dorsal root ganglia lysate, suggesting that these receptors can form heterodimers. Consistent with this hypothesis, in cells expressing either one of the opioid receptors together with ORL1, prolonged ORL1 receptor activation via nociceptin ap...

  18. Proviral Progeny of Heterodimeric Virions Reveal a High Crossover Rate for Human Immunodeficiency Virus Type 2▿

    OpenAIRE

    Mukherjee, Sayandip; Lee, Hui-Ling Rose; Ron, Yacov; Dougherty, Joseph P.

    2006-01-01

    Human immunodeficiency virus type 1 (HIV-1), the causative agent of AIDS in humans, exhibits a very high rate of recombination. Bearing in mind the significant epidemiological and clinical contrast between HIV-2 and HIV-1 as well as the critical role that recombination plays in viral evolution, we examined the nature of HIV-2 recombination. Towards this end, a strategy was devised to measure the rate of crossover of HIV-2 by evaluating recombinant progeny produced exclusively by heterodimeric...

  19. Structural basis of the heterodimerization of the MST and RASSF SARAH domains in the Hippo signalling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Eunha [Korea Basic Science Institute, Ochang-eup Yeongudangiro 162, Cheongwon-gun, Chungbuk 363-883 (Korea, Republic of); Korea University, Seoul 136-701 (Korea, Republic of); Cheong, Hae-Kap [Korea Basic Science Institute, Ochang-eup Yeongudangiro 162, Cheongwon-gun, Chungbuk 363-883 (Korea, Republic of); Mushtaq, Ameeq Ul [Korea University, Sejong-ro, Sejong 339-700 (Korea, Republic of); Kim, Hye-Yeon; Yeo, Kwon Joo; Kim, Eunhee [Korea Basic Science Institute, Ochang-eup Yeongudangiro 162, Cheongwon-gun, Chungbuk 363-883 (Korea, Republic of); Lee, Woo Cheol; Hwang, Kwang Yeon [Korea University, Seoul 136-701 (Korea, Republic of); Cheong, Chaejoon, E-mail: cheong@kbsi.re.kr [Korea Basic Science Institute, Ochang-eup Yeongudangiro 162, Cheongwon-gun, Chungbuk 363-883 (Korea, Republic of); Jeon, Young Ho, E-mail: cheong@kbsi.re.kr [Korea University, Sejong-ro, Sejong 339-700 (Korea, Republic of); Korea Basic Science Institute, Ochang-eup Yeongudangiro 162, Cheongwon-gun, Chungbuk 363-883 (Korea, Republic of)

    2014-07-01

    The heterodimeric structure of the MST1 and RASSF5 SARAH domains is presented. A comparison of homodimeric and heterodimeric interactions provides a structural basis for the preferential association of the SARAH heterodimer. Despite recent progress in research on the Hippo signalling pathway, the structural information available in this area is extremely limited. Intriguingly, the homodimeric and heterodimeric interactions of mammalian sterile 20-like (MST) kinases through the so-called ‘SARAH’ (SAV/RASSF/HPO) domains play a critical role in cellular homeostasis, dictating the fate of the cell regarding cell proliferation or apoptosis. To understand the mechanism of the heterodimerization of SARAH domains, the three-dimensional structures of an MST1–RASSF5 SARAH heterodimer and an MST2 SARAH homodimer were determined by X-ray crystallography and were analysed together with that previously determined for the MST1 SARAH homodimer. While the structure of the MST2 homodimer resembled that of the MST1 homodimer, the MST1–RASSF5 heterodimer showed distinct structural features. Firstly, the six N-terminal residues (Asp432–Lys437), which correspond to the short N-terminal 3{sub 10}-helix h1 kinked from the h2 helix in the MST1 homodimer, were disordered. Furthermore, the MST1 SARAH domain in the MST1–RASSF5 complex showed a longer helical structure (Ser438–Lys480) than that in the MST1 homodimer (Val441–Lys480). Moreover, extensive polar and nonpolar contacts in the MST1–RASSF5 SARAH domain were identified which strengthen the interactions in the heterodimer in comparison to the interactions in the homodimer. Denaturation experiments performed using urea also indicated that the MST–RASSF heterodimers are substantially more stable than the MST homodimers. These findings provide structural insights into the role of the MST1–RASSF5 SARAH domain in apoptosis signalling.

  20. Heterodimeric barnase-barstar vaccine molecules: influence of one versus two targeting units specific for antigen presenting cells.

    Directory of Open Access Journals (Sweden)

    Heidi Cecilie Larsen Spång

    Full Text Available It is known that targeting of antigen to antigen presenting cells (APC increases immune responses. However, it is unclear if more than one APC-specific targeting unit in the antigenic molecule will increase responses. To address this issue, we have here made heterodimeric vaccine molecules that each express four different fusion subunits. The bacterial ribonuclease barnase and its inhibitor barstar interact with high affinity, and the barnase-barstar complex was therefore used as a dimerization unit. Barnase and barstar were fused N-terminally with single chain fragment variable (scFvs targeting units specific for either MHC class II molecules on APC or the hapten 5-iodo-4-hydroxy-3-nitrophenylacetyl (NIP. C-terminal antigenic fusions were either the fluorescent protein mCherry or scFv(315 derived from myeloma protein M315. The heterodimeric vaccine molecules were formed both in vitro and in vivo. Moreover, the four different fused moieties appeared to fold correctly since they retained their specificity and function. DNA vaccination with MHC class II-targeted vaccine induced higher mCherry-specific IgG1 responses compared to non-targeted control. Since mCherry and MHC class II are in trans in this heterodimer, this suggests that heterodimeric proteins are formed in vivo without prior protein purification. Surprisingly, one targeting moiety was sufficient for the increased IgG1 response, and addition of a second targeting moiety did not increase responses. Similar results were found in in vitro T cell assays; vaccine molecules with one targeting unit were as potent as those with two. In combination with the easy cloning strategy, the heterodimeric barnase-barstar vaccine molecule could provide a flexible platform for development of novel DNA vaccines with increased potency.

  1. Reperfusion Therapy with Rapamycin Attenuates Myocardial Infarction through Activation of AKT and ERK

    Directory of Open Access Journals (Sweden)

    Scott M. Filippone

    2017-01-01

    Full Text Available Prompt coronary reperfusion is the gold standard for minimizing injury following acute myocardial infarction. Rapamycin, mammalian target of Rapamycin (mTOR inhibitor, exerts preconditioning-like cardioprotective effects against ischemia/reperfusion (I/R injury. We hypothesized that Rapamycin, given at the onset of reperfusion, reduces myocardial infarct size through modulation of mTOR complexes. Adult C57 male mice were subjected to 30 min of myocardial ischemia followed by reperfusion for 1 hour/24 hours. Rapamycin (0.25 mg/kg or DMSO (7.5% was injected intracardially at the onset of reperfusion. Post-I/R survival (87% and cardiac function (fractional shortening, FS: 28.63±3.01% were improved in Rapamycin-treated mice compared to DMSO (survival: 63%, FS: 17.4±2.6%. Rapamycin caused significant reduction in myocardial infarct size (IS: 26.2±2.2% and apoptosis (2.87±0.64% as compared to DMSO-treated mice (IS: 47.0±2.3%; apoptosis: 7.39±0.81%. Rapamycin induced phosphorylation of AKT S473 (target of mTORC2 but abolished ribosomal protein S6 phosphorylation (target of mTORC1 after I/R. Rapamycin induced phosphorylation of ERK1/2 but inhibited p38 phosphorylation. Infarct-limiting effect of Rapamycin was abolished with ERK inhibitor, PD98059. Rapamycin also attenuated Bax and increased Bcl-2/Bax ratio. These results suggest that reperfusion therapy with Rapamycin protects the heart against I/R injury by selective activation of mTORC2 and ERK with concurrent inhibition of mTORC1 and p38.

  2. Homo- and heterodimerization of ROCO kinases: LRRK2 kinase inhibition by the LRRK2 ROCO fragment.

    Science.gov (United States)

    Klein, Christian L; Rovelli, Giorgio; Springer, Wolfdieter; Schall, Christoph; Gasser, Thomas; Kahle, Philipp J

    2009-11-01

    Mutations in the gene encoding leucine-rich repeat kinase 2 (LRRK2) are the most common cause of autosomal-dominant familial and late-onset sporadic Parkinson's disease (PD). LRRK2 is a large multi-domain protein featuring a GTP-binding C-terminal of Ras of complex proteins (ROC) (ROCO) domain combination unique for the ROCO protein family, directly followed by a kinase domain. Dimerization is a well-established phenomenon among protein kinases. Here, we confirm LRRK2 self-interaction, and provide evidence for general homo- and heterodimerization potential among the ROCO kinase family (LRRK2, LRRK1, and death-associated protein kinase 1). The ROCO domain was critically, though not exclusively involved in dimerization, as a LRRK2 deletion mutant lacking the ROCO domain retained dimeric properties. GTP binding did not appear to influence ROCO(LRRK2) self-interaction. Interestingly, ROCO(LRRK2) fragments exerted an inhibitory effect on both wild-type and the elevated G2019S LRRK2 autophosphorylation activity. Insertion of PD mutations into ROCO(LRRK2) reduced self-interaction and led to a reduction of LRRK2 kinase inhibition. Collectively, these results suggest a functional link between ROCO interactions and kinase activity of wild-type and mutant LRRK2. Importantly, our finding of ROCO(LRRK2) fragment-mediated LRRK2 kinase inhibition offers a novel lead for drug design and thus might have important implications for new therapeutic avenues in PD.

  3. Subnanometre-resolution electron cryomicroscopy structure of a heterodimeric ABC exporter.

    Science.gov (United States)

    Kim, JungMin; Wu, Shenping; Tomasiak, Thomas M; Mergel, Claudia; Winter, Michael B; Stiller, Sebastian B; Robles-Colmanares, Yaneth; Stroud, Robert M; Tampé, Robert; Craik, Charles S; Cheng, Yifan

    2015-01-15

    ATP-binding cassette (ABC) transporters translocate substrates across cell membranes, using energy harnessed from ATP binding and hydrolysis at their nucleotide-binding domains. ABC exporters are present both in prokaryotes and eukaryotes, with examples implicated in multidrug resistance of pathogens and cancer cells, as well as in many human diseases. TmrAB is a heterodimeric ABC exporter from the thermophilic Gram-negative eubacterium Thermus thermophilus; it is homologous to various multidrug transporters and contains one degenerate site with a non-catalytic residue next to the Walker B motif. Here we report a subnanometre-resolution structure of detergent-solubilized TmrAB in a nucleotide-free, inward-facing conformation by single-particle electron cryomicroscopy. The reconstructions clearly resolve characteristic features of ABC transporters, including helices in the transmembrane domain and nucleotide-binding domains. A cavity in the transmembrane domain is accessible laterally from the cytoplasmic side of the membrane as well as from the cytoplasm, indicating that the transporter lies in an inward-facing open conformation. The two nucleotide-binding domains remain in contact via their carboxy-terminal helices. Furthermore, comparison between our structure and the crystal structures of other ABC transporters suggests a possible trajectory of conformational changes that involves a sliding and rotating motion between the two nucleotide-binding domains during the transition from the inward-facing to outward-facing conformations.

  4. Heterodimerization of Two Pathological Mutants Enhances the Activity of Human Phosphomannomutase2.

    Directory of Open Access Journals (Sweden)

    Giuseppina Andreotti

    Full Text Available The most frequent disorder of glycosylation is due to mutations in the gene encoding phosphomannomutase2 (PMM2-CDG. For this disease, which is autosomal and recessive, there is no cure at present. Most patients are composite heterozygous and carry one allele encoding an inactive mutant, R141H, and one encoding a hypomorphic mutant. Phosphomannomutase2 is a dimer. We reproduced composite heterozygosity in vitro by mixing R141H either with the wild type protein or the most common hypomorphic mutant F119L and compared the quaternary structure, the activity and the stability of the heterodimeric enzymes. We demonstrated that the activity of R141H/F119L heterodimers in vitro, which reproduces the protein found in patients, has the same activity of wild type/R141H, which reproduces the protein found in healthy carriers. On the other hand the stability of R141H/F119L appears to be reduced both in vitro and in vivo. These findings suggest that a therapy designed to enhance protein stability such as those based on pharmacological chaperones or modulation of proteostasis could be beneficial for PMM2-CDG patients carrying R141H/F119L genotype as well as for other genotypes where protein stability rather than specific activity is affected by mutations.

  5. Mammalian target of rapamycin inhibitors for treatment in tuberous sclerosis

    Directory of Open Access Journals (Sweden)

    Won Seop Kim

    2011-06-01

    Full Text Available Tuberous sclerosis complex (TSC is a genetic multisystem disorder that results from mutations in the TSC1 or TSC2 genes, and is associated with hamartomas in several organs, including subependymal giant cell tumors. The neurological manifestations of TSC are particularly challenging and include infantile spasms, intractable epilepsy, cognitive disabilities, and autism. The TSC1- and TSC2-encoded proteins modulate cell function via the mammalian target of rapamycin (mTOR signaling cascade, and are key factors in the regulation of cell growth and proliferation. The mTOR pathway provides an intersection for an intricate network of protein cascades that respond to cellular nutrition, energy levels, and growth factor stimulation. In the brain, TSC1 and TSC2 have been implicated in cell body size, dendritic arborization, axonal outgrowth and targeting, neuronal migration, cortical lamination, and spine formation. The mTOR pathway represents a logical candidate for drug targeting, because mTOR regulates multiple cellular functions that may contribute to epileptogenesis, including protein synthesis, cell growth and proliferation, and synaptic plasticity. Antagonism of the mTOR pathway with rapamycin and related compounds may provide new therapeutic options for TSC patients.

  6. Blood-brain barrier leakage after status epilepticus in rapamycin-treated rats II : Potential mechanisms

    NARCIS (Netherlands)

    van Vliet, Erwin A; Otte, Wim M; Wadman, Wytse J; Aronica, Eleonora; Kooij, Gijs; de Vries, Helga E; Dijkhuizen, Rick M; Gorter, Jan A

    OBJECTIVE: Blood-brain barrier (BBB) leakage may play a pro-epileptogenic role after status epilepticus. In the accompanying contrast-enhanced magnetic resonance imaging (CE-MRI) study we showed that the mammalian target of rapamycin (mTOR) inhibitor rapamycin reduced BBB leakage and seizure

  7. Assessment of Response of Kidney Tumors to Rapamycin and Atorvastatin in Tsc1+/- Mice.

    Science.gov (United States)

    Shen, Ming Hong; Samsel, Paulina; Shen, Louise L; Narov, Kalin; Yang, Jian; Sampson, Julian R

    2017-10-01

    Atorvastatin is widely used to lower blood cholesterol and to reduce risk of cardiovascular disease-associated complications. Epidemiological investigations and preclinical studies suggest that statins such as atorvastatin have antitumor activity for various types of cancer. Tuberous sclerosis (TSC) is a tumor syndrome caused by TSC1 or TSC2 mutations that lead to aberrant activation of mTOR and tumor formation in multiple organs. Previous studies have demonstrated that atorvastatin selectively suppressed growth and proliferation of mouse Tsc2 null embryonic fibroblasts through inhibition of mTOR. However, atorvastatin alone did not reduce tumor burden in the liver and kidneys of Tsc2+/- mice as assessed by histological analysis, and no combination therapy of rapamycin and atorvastatin has been tried. In this study, we used T2-weighted magnetic resonance imaging to track changes in tumor number and size in the kidneys of a Tsc1+/- mouse model and to assess the efficacy of rapamycin and atorvastatin alone and as a combination therapy. We found that rapamycin alone or rapamycin combined with atorvastatin significantly reduced tumor burden, while atorvastatin alone did not. Combined therapy with rapamycin and atorvastatin appeared to be more effective for treating renal tumors than rapamycin alone, but the difference was not statistically significant. We conclude that combined therapy with rapamycin and atorvastatin is unlikely to provide additional benefit over rapamycin as a single agent in the treatment of Tsc-associated renal tumors. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  8. The incidence, management, and evolution of rapamycin-related side effects in kidney transplant recipients

    NARCIS (Netherlands)

    Verhave, J.C.; Boucher, A.; Dandavino, R.; Collette, S.; Senecal, L.; Hebert, M.J.; Girardin, C.; Cardinal, H.

    2014-01-01

    Conversion from a calcineurin-inhibitor-based immunosuppression to a rapamycin-based immunosuppression may preserve kidney graft function. The side effects of rapamycin can limit its usefulness, but their management and evolution are rarely reported in clinical trials. We performed a retrospective

  9. Rapamycin-induced inhibition of HTLV-I LTR activity is rescued by c-Myb

    Directory of Open Access Journals (Sweden)

    Lever Andrew ML

    2007-04-01

    Full Text Available Abstract Background Rapamycin is an immunosuppressive which represses translation of transcripts harbouring a polypyrimidine motif downstream of the mRNA cap site through the mammalian target of rapamycin complex. It inhibits the abnormal autologous proliferation of T-cell clones containing a transcriptionally active human T-lymphotropic virus, type I (HTLV-I provirus, generated from infected subjects. We showed previously that this effect is independent of the polypyrimidine motifs in the viral long terminal repeat (LTR R region suggesting that HTLV-I transcription, and not translation, is being affected. Here we studied whether rapamycin is having an effect on a specific transcription factor pathway. Further, we investigated whether mRNAs encoding transcription factors involved in HTLV-I transcriptional activation, specifically CREB, Ets and c-Myb, are implicated in the rapamycin-sensitivity of the HTLV-I LTR. Results An in vitro analysis of the role of SRE- and NF-κB-mediated transcription highlighted the latter as rapamycin sensitive. Over-expression of c-Myb reversed the rapamycin effect. Conclusion The sensitivity of HTLV-I transcription to rapamycin may be effected through an NF-κB-pathway associated with the rapamycin-sensitive mTORC1 cellular signalling network.

  10. Rapamycin Induces Heme Oxygenase-1 in Liver but Inhibits Bile Flow Recovery after Ischemia

    NARCIS (Netherlands)

    Kist, Alwine; Wakkie, Joris; Madu, Max; Versteeg, Ruth; ten Berge, Judith; Nikolic, Andrej; Nieuwenhuijs, Vincent B.; Porte, Robert J.; Padbury, Robert T. A.; Barritt, Greg J.

    Background/Aims. Rapamycin, which is employed in the management of patients undergoing liver surgery, induces the synthesis of heme oxygenase-1 (HO-1) in some non-liver cell types. The aim was to investigate whether rapamycin can induce HO-1 expression in the liver, and to test the effects of

  11. Rapamycin and mTORC1 Inhibition in the Mouse: Skin Cancer Prevention

    Science.gov (United States)

    Athar, Mohammad; Kopelovich, Levy

    2011-01-01

    Therapeutic and preventive effects of rapamycin include reduced risk of non-melanoma skin cancer (NMSC). In this issue of the journal (beginning on page XXX), Checkley et al. report that rapamycin inhibits mammalian target of rapamycin (mTOR) complex 1 in murine epidermis, thereby inhibiting tumor promotion mediated by tetradecanoyl phorbol-13 acetate (TPA) in association with a strong anti-inflammatory effect. Rapamycin is an immunosuppressive drug for preventing graft rejection in organ transplant recipients and reduces the risk of NMSC and Kaposi’s sarcoma in this population, albeit by mechanisms distinct from immunosuppression. Important future directions include identifying molecular predictors of rapamycin/rapalog sensitivity or resistance (potentially, for example, PI3K pathway alterations and KRAS mutations) and combined non-rapalog, mTOR-targeting approaches, all of which should increase efficacy and minimize toxicity. PMID:21733819

  12. Rapamycin attenuates mitochondrial dysfunction via activation of mitophagy in experimental ischemic stroke

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qiang [Department of Neurology, Shanghai Sixth People’s Hospital, Shanghai Jiao Tong University, Shanghai 200233 (China); Department of Neurology, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011 (China); Zhang, Ting [Department of Neurology, Shanghai Sixth People’s Hospital, Shanghai Jiao Tong University, Shanghai 200233 (China); Wang, Jixian [Department of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025 (China); Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030 (China); Zhang, Zhijun [Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030 (China); Zhai, Yu [Department of Neurology, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011 (China); Yang, Guo-Yuan, E-mail: gyyang0626@gmail.com [Department of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025 (China); Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030 (China); Sun, Xiaojiang, E-mail: sunxj19@gmail.com [Department of Neurology, Shanghai Sixth People’s Hospital, Shanghai Jiao Tong University, Shanghai 200233 (China)

    2014-02-07

    Highlights: • Rapamycin enhances mitophagy via increasing p62 translocation to the mitochondria. • Rapamycin attenuates brain ischemic damage and improves mitochondrial function. • The protection of rapamycin to mitochondrial is linked to enhanced mitophagy. - Abstract: Rapamycin has been demonstrated to exhibit neuroprotective functions via the activation of autophagy in a cerebral ischemia model. However, the involvement of mitophagy in this process and its contribution to the protection of mitochondrial function remains unknown. The present study explored the characteristics of mitophagy after cerebral ischemia and the effect of rapamycin on mitochondrial function. Male Sprague–Dawley rats underwent transient middle cerebral artery occlusion (tMCAO). Neurological deficits scores; infarct volumes; mitophagy morphology; and the levels of malondialdehyde (MDA), adenosine triphosphate (ATP) and mitochondrial membrane potentials (Δψm) were examined. The expression of LC3, Beclin-1 and p62 in the mitochondrial fraction combined with transmission electronic microscopy were used to explore mitophagic activity after ischemia. We also blocked autophagosome formation using 3-methyladenine (3-MA) to check the linkage between the mitochondrial protective effect of rapamycin and enhanced mitophagy. We observed that rapamycin significantly enhanced mitophagy, as evidenced by the increase in LC3-II and Beclin-1 expression in the mitochondria and p62 translocation to the mitochondria. Rapamycin reduced infarct volume, improved neurological outcomes and inhibited mitochondrial dysfunction compared with the control animals (p < 0.05). However, these protective effects were reversed by 3-methyladenine treatment after rapamycin. The present study indicates that rapamycin treatment attenuates mitochondrial dysfunction following cerebral ischemia, which is linked to enhanced mitophagy.

  13. Lung function response and side effects to rapamycin for lymphangioleiomyomatosis: a prospective national cohort study.

    Science.gov (United States)

    Bee, Janet; Fuller, Sharon; Miller, Suzanne; Johnson, Simon R

    2017-10-09

    Mechanistic target of rapamycin inhibitors reduce loss of lung function in lymphangioleiomyomatosis (LAM), although their benefit varies between individuals. We examined lung function response and side effects to rapamycin in a national cohort. Subjects were receiving rapamycin for progressive lung disease. Clinical evaluation, detailed phenotyping, serial lung function, rapamycin and safety monitoring were performed according to a clinical protocol. Lung function change, measured as FEV1 slope (ΔFEV1), was reported for those treated for 1 year or longer. Rapamycin was associated with improved ΔFEV1 in 21 individuals where pretreatment data were available (p<0.0001). In 47 treated for a mean duration of 35.8 months, mean ΔFEV1 was +11 (SD 75) mL/year, although it varied from +254 to -148 mL/year. The quartile with the highest positive ΔFEV1 had greater pretreatment FEV1 (p=0.02) and shorter disease durations (p=0.02) than the lowest quartile. Serum rapamycin level was positively associated with side effects (p=0.02) but not ΔFEV1 over 1 year. Within the first month of therapy, apthous ulcers, nausea and diarrhoea were associated with higher rapamycin levels. Acne, oedema and menstrual irregularities tended to increase over the first year of therapy. At the end of observation, the prevalence of side effects was 5% or less. Rapamycin reduces lung function loss in LAM, although in some, ΔFEV1 continues to fall at an accelerated rate. Poor response to rapamycin was associated with lower pretreatment lung function and longer disease duration but not serum level. Early intervention with low-dose rapamycin may preserve lung function and reduce side effects. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  14. Inhibition of mammalian target of rapamycin reduces epileptogenesis and blood-brain barrier leakage but not microglia activation.

    NARCIS (Netherlands)

    van Vliet, E.A.; Forte, G.; Holtman, L.; den Burger, J.C.G.; Sinjewel, A.; de Vries, H.E.; Aronica, E.; Gorter, J.A.

    2012-01-01

    Purpose: Previous studies have shown that inhibition of the mammalian target of rapamycin (mTOR) pathway with rapamycin prevents epileptogenesis after pharmacologically induced status epilepticus (SE) in rat models of temporal lobe epilepsy. Because rapamycin is also known for its immunosuppressant

  15. Blood-brain barrier leakage after status epilepticus in rapamycin-treated rats I : Magnetic resonance imaging

    NARCIS (Netherlands)

    van Vliet, Erwin A; Otte, Wim M; Wadman, Wytse J; Aronica, Eleonora; Kooij, Gijs; de Vries, Helga E; Dijkhuizen, Rick M; Gorter, Jan A

    OBJECTIVE: The mammalian target of rapamycin (mTOR) pathway has received increasing attention as a potential antiepileptogenic target. Treatment with the mTOR inhibitor rapamycin after status epilepticus reduces the development of epilepsy in a rat model. To study whether rapamycin mediates this

  16. Demonstration of heterodimeric fibrinogen molecules partially conjugated with albumin in a novel dysfibrinogen: fibrinogen Mannheim V.

    Science.gov (United States)

    Dempfle, Carl-Erik; George, Peter M; Borggrefe, Martin; Neumaier, Michael; Brennan, Stephen O

    2009-07-01

    A 30-year-old female experienced three miscarriages in early pregnancy. Extensive laboratory screening showed a low plasma fibrinogen level of approximately l g/l detected by PT-derived fibrinogen assay. The fibrinogen level in the immunological assay was 3 g/l. The functional Clauss assay yielded an intermediate result of 1.78 g/l. During her fourth and fifth pregnancy, the patient received fibrinogen concentrates (Haemocomplettan, CLS Behring, Marburg, Germany), starting with 4 grams of human fibrinogen, followed by 2 grams every second day until the 15(th) week of pregnancy. The further course of these pregnancies was uneventful. SDS-PAGE and immunoblotting showed doublet bands in the positions of the high-molecular weight (HMW)- and low-molecular-weight (LMW)-fibrinogen, a single LMW' fibrinogen band, plus additional bands with higher molecular weight than HMW-fibrinogen, which were also reactive with anti-human serum albumin (HSA) antiserum. These bands correspond to variant fibrinogen conjugated with albumin. Reduced SDS-PAGE and immunoblotting using polyclonal anti-fibrinopeptide A antiserum disclosed one additional Aalpha-chain band with lower molecular weight. Amplification and sequencing of exon 5 of the alpha gene indicated heterozygosity for a novel single nucleotide deletion at codon Aalpha494 (C1537delA). His494 is replaced by Pro and this is followed by 23 (LMKLPSSTLPQLEKHSQ VSSHLC) new amino acids before premature truncation after Cys517, yielding a free C-terminal cysteine, which may link with albumin. This new fibrinogen mutation, leads to a balanced array of homo- and heterodimeric fibrinogen molecules, some of which are conjugated to albumin.

  17. Kinetic studies of the folding of heterodimeric monellin: evidence for switching between alternative parallel pathways.

    Science.gov (United States)

    Aghera, Nilesh; Udgaonkar, Jayant B

    2012-07-13

    Determining whether or not a protein uses multiple pathways to fold is an important goal in protein folding studies. When multiple pathways are present, defined by transition states that differ in their compactness and structure but not significantly in energy, they may manifest themselves by causing the dependence on denaturant concentration of the logarithm of the observed rate constant of folding to have an upward curvature. In this study, the folding mechanism of heterodimeric monellin [double-chain monellin (dcMN)] has been studied over a range of protein and guanidine hydrochloride (GdnHCl) concentrations, using the intrinsic tryptophan fluorescence of the protein as the probe for the folding reaction. Refolding is shown to occur in multiple kinetic phases. In the first stage of refolding, which is silent to any change in intrinsic fluorescence, the two chains of monellin bind to one another to form an encounter complex. Interrupted folding experiments show that the initial encounter complex folds to native dcMN via two folding routes. A productive folding intermediate population is identified on one route but not on both of these routes. Two intermediate subpopulations appear to form in a fast kinetic phase, and native dcMN forms in a slow kinetic phase. The chevron arms for both the fast and slow phases of refolding are shown to have upward curvatures, suggesting that at least two pathways each defined by a different intermediate are operational during these kinetic phases of structure formation. Refolding switches from one pathway to the other as the GdnHCl concentration is increased. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Drosophila Ncd reveals an evolutionarily conserved powerstroke mechanism for homodimeric and heterodimeric kinesin-14s.

    Science.gov (United States)

    Zhang, Pengwei; Dai, Wei; Hahn, Juergen; Gilbert, Susan P

    2015-05-19

    Drosophila melanogaster kinesin-14 Ncd cross-links parallel microtubules at the spindle poles and antiparallel microtubules within the spindle midzone to play roles in bipolar spindle assembly and proper chromosome distribution. As observed for Saccharomyces cerevisiae kinesin-14 Kar3Vik1 and Kar3Cik1, Ncd binds adjacent microtubule protofilaments in a novel microtubule binding configuration and uses an ATP-promoted powerstroke mechanism. The hypothesis tested here is that Kar3Vik1 and Kar3Cik1, as well as Ncd, use a common ATPase mechanism for force generation even though the microtubule interactions for both Ncd heads are modulated by nucleotide state. The presteady-state kinetics and computational modeling establish an ATPase mechanism for a powerstroke model of Ncd that is very similar to those determined for Kar3Vik1 and Kar3Cik1, although these heterodimers have one Kar3 catalytic motor domain and a Vik1/Cik1 partner motor homology domain whose interactions with microtubules are not modulated by nucleotide state but by strain. The results indicate that both Ncd motor heads bind the microtubule lattice; two ATP binding and hydrolysis events are required for each powerstroke; and a slow step occurs after microtubule collision and before the ATP-promoted powerstroke. Note that unlike conventional myosin-II or other processive molecular motors, Ncd requires two ATP turnovers rather than one for a single powerstroke-driven displacement or step. These results are significant because all metazoan kinesin-14s are homodimers, and the results presented show that despite their structural and functional differences, the heterodimeric and homodimeric kinesin-14s share a common evolutionary structural and mechanochemical mechanism for force generation.

  19. Proprotein convertases generate a highly functional heterodimeric form of thymic stromal lymphopoietin in humans.

    Science.gov (United States)

    Poposki, Julie A; Klingler, Aiko I; Stevens, Whitney W; Peters, Anju T; Hulse, Kathryn E; Grammer, Leslie C; Schleimer, Robert P; Welch, Kevin C; Smith, Stephanie S; Sidle, Douglas M; Conley, David B; Tan, Bruce K; Kern, Robert C; Kato, Atsushi

    2017-05-01

    Thymic stromal lymphopoietin (TSLP) is known to be elevated and truncated in nasal polyps (NPs) of patients with chronic rhinosinusitis and might play a significant role in type 2 inflammation in this disease. However, neither the structure nor the role of the truncated products of TSLP has been studied. We sought to investigate the mechanisms of truncation of TSLP in NPs and the function of the truncated products. We incubated recombinant human TSLP with NP extracts, and determined the protein sequence of the truncated forms of TSLP using Edman protein sequencing and matrix-assisted laser desorption/ionization-time of flight mass spectrometry. We investigated the functional activity of truncated TSLP using a PBMC-based bioassay. Edman sequencing and mass spectrometry results indicated that NP extracts generated 2 major truncated products, TSLP (residues 29-124) and TSLP (131-159). Interestingly, these 2 products remained linked with disulfide bonds and presented as a dimerized form, TSLP (29-124 + 131-159). We identified that members of the proprotein convertase were rate-limiting enzymes in the truncation of TSLP between residues 130 and 131 and generated a heterodimeric unstable metabolite TSLP (29-130 + 131-159). Carboxypeptidase N immediately digested 6 amino acids from the C terminus of the longer subunit of TSLP to generate a stable dimerized form, TSLP (29-124 + 131-159), in NPs. These truncations were homeostatic but primate-specific events. A metabolite TSLP (29-130 + 131-159) strongly activated myeloid dendritic cells and group 2 innate lymphoid cells compared with mature TSLP. Posttranslational modifications control the functional activity of TSLP in humans and overproduction of TSLP may be a key trigger for the amplification of type 2 inflammation in diseases. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  20. TaqManR proximity ligation technology for the detection of heterodimeric adhesion receptors on lymphocytes.

    Science.gov (United States)

    Gehwolf, Renate; Band, Elisabeth; Trost, Andrea; Iglseder, Bernhard; Trinka, Eugen; Haschke-Becher, Elisabeth; Kraus, Jörg; Harrer, Andrea

    2014-02-01

    TaqMan(R) proximity ligation technology (TaqMan(R) PLA) is an innovative advancement of immuno PCR. It allows a fast and quantitative detection of vicinal proteins or protein-protein interactions from cell lysates by combining antibody-antigen binding with a real-time PCR detection. We tested if TaqMan(R) PLA also was applicable to investigate and relatively quantitate adhesion receptor heterodimers such as the alpha-4/beta-1 integrin on the surface of intact cells. Both, alpha-4, beta-1 and the alpha-4/beta-1 heterodimer were detected on the surface of lymphocytes by TaqMan(R) PLA. Results were specific, reproducible and comparable to flow cytometric data. However, preciseness of reactions varied dependent on the antibody pairs used. Co-detection of proximate identical subunits suggested clusters of alpha-4 and/or beta-1 on the cell surface which we confirmed by microscopy. We conclude that real-time PCR-based TaqMan(R) PLA is of limited applicability to investigate heterodimeric receptor molecules such as the alpha-4/beta-1 integrin. Determination of an abundance ratio of alpha-4/beta-1 in relation to total alpha-4 or beta-1 was not possible and real-time detection did not allow conclusions on the surface distribution of molecules. The related in situ PLA developed for microscopy allows visualizing proximate protein interactions and might be an interesting alternative for research into receptor heterodimers and their surface distribution on immune cells. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Mammalian target of rapamycin inhibitors for treatment in tuberous sclerosis

    Directory of Open Access Journals (Sweden)

    Won Seop Kim

    2013-06-01

    Full Text Available Korean J Pediatr 2011;54:241-5. &lt;a href='http://dx.doi.org/10.3345/kjp.2011.54.6.241'&gt;http://dx.doi.org/10.3345/kjp.2011.54.6.241&lt;/a&gt;. PMID: 21949518 [PubMed] &lt;div style="border-top:1px solid #0092C8"&gt;&lt;/div&gt; The following article&lt;sup&gt;1&lt;/sup&gt; is being retracted as a part of the manuscript was plagiarized. Yeong-Ho Rha, MD, PhD Editor-in-Chief, Korean J Pediatr 1.Kim WS. Mammalian target of rapamycin inhibitors for treatment in tuberous sclerosis. Korean J Pediatr 2011;54:241-5.

  2. An approach to analyse the specific impact of rapamycin on mRNA-ribosome association

    Directory of Open Access Journals (Sweden)

    Jaquier-Gubler Pascale

    2008-08-01

    Full Text Available Abstract Background Recent work, using both cell culture model systems and tumour derived cell lines, suggests that the differential recruitment into polysomes of mRNA populations may be sufficient to initiate and maintain tumour formation. Consequently, a major effort is underway to use high density microarray profiles to establish molecular fingerprints for cells exposed to defined drug regimes. The aim of these pharmacogenomic approaches is to provide new information on how drugs can impact on the translational read-out within a defined cellular background. Methods We describe an approach that permits the analysis of de-novo mRNA-ribosome association in-vivo during short drug exposures. It combines hypertonic shock, polysome fractionation and high-throughput analysis to provide a molecular phenotype of translationally responsive transcripts. Compared to previous translational profiling studies, the procedure offers increased specificity due to the elimination of the drugs secondary effects (e.g. on the transcriptional read-out. For this pilot "proof-of-principle" assay we selected the drug rapamycin because of its extensively studied impact on translation initiation. Results High throughput analysis on both the light and heavy polysomal fractions has identified mRNAs whose re-recruitment onto free ribosomes responded to short exposure to the drug rapamycin. The results of the microarray have been confirmed using real-time RT-PCR. The selective down-regulation of TOP transcripts is also consistent with previous translational profiling studies using this drug. Conclusion The technical advance outlined in this manuscript offers the possibility of new insights into mRNA features that impact on translation initiation and provides a molecular fingerprint for transcript-ribosome association in any cell type and in the presence of a range of drugs of interest. Such molecular phenotypes defined pre-clinically may ultimately impact on the evaluation of

  3. Mammalian target of rapamycin (mTor) mediates tau protein dyshomeostasis: implication for Alzheimer disease.

    Science.gov (United States)

    Tang, Zhi; Bereczki, Erika; Zhang, Haiyan; Wang, Shan; Li, Chunxia; Ji, Xinying; Branca, Rui M; Lehtiö, Janne; Guan, Zhizhong; Filipcik, Peter; Xu, Shaohua; Winblad, Bengt; Pei, Jin-Jing

    2013-05-31

    Previous evidence from post-mortem Alzheimer disease (AD) brains and drug (especially rapamycin)-oriented in vitro and in vivo models implicated an aberrant accumulation of the mammalian target of rapamycin (mTor) in tangle-bearing neurons in AD brains and its role in the formation of abnormally hyperphosphorylated tau. Compelling evidence indicated that the sequential molecular events such as the synthesis and phosphorylation of tau can be regulated through p70 S6 kinase, the well characterized immediate downstream target of mTor. In the present study, we further identified that the active form of mTor per se accumulates in tangle-bearing neurons, particularly those at early stages in AD brains. By using mass spectrometry and Western blotting, we identified three phosphoepitopes of tau directly phosphorylated by mTor. We have developed a variety of stable cell lines with genetic modification of mTor activity using SH-SY5Y neuroblastoma cells as background. In these cellular systems, we not only confirmed the tau phosphorylation sites found in vitro but also found that mTor mediates the synthesis and aggregation of tau, resulting in compromised microtubule stability. Changes of mTor activity cause fluctuation of the level of a battery of tau kinases such as protein kinase A, v-Akt murine thymoma viral oncogene homolog-1, glycogen synthase kinase 3β, cyclin-dependent kinase 5, and tau protein phosphatase 2A. These results implicate mTor in promoting an imbalance of tau homeostasis, a condition required for neurons to maintain physiological function.

  4. Rapamycin Ameliorates Proteinuria and Restores Nephrin and Podocin Expression in Experimental Membranous Nephropathy

    Directory of Open Access Journals (Sweden)

    Stavros Stratakis

    2013-01-01

    Full Text Available Objective. Recent studies have shown a beneficial effect of rapamycin in passive and active Heymann Nephritis (HN. However, the mechanisms underlying this beneficial effect have not been elucidated. Methods. Passive Heymann Nephritis (PHN was induced by a single intravenous infusion of anti-Fx1 in 12 Sprague-Dawley male rats. One week later, six of these rats were commenced on daily treatment with subcutaneous rapamycin 0.5 mgr/kg (PHN-Rapa. The remaining six rats were used as the proteinuric control group (PHN while six more rats without PHN were given the rapamycin solvent and served as the healthy control group (HC. All rats were sacrificed at the end of the 7th week. Results. Rapamycin significantly reduced proteinuria during the autologous phase of PHN. Histological lesions were markedly improved by rapamycin. Immunofluorescence revealed attenuated deposits of autologous alloantibodies in treated rats. Untreated rats showed decreased glomerular content of both nephrin and podocin whereas rapamycin restored their expression. Conclusions. Rapamycin monotherapy significantly improves proteinuria and histological lesions in experimental membranous nephropathy. This beneficial effect may be mediated by inhibition of the alloimmune response during the autologous phase of PHN and by restoration of the normal expression of the podocyte proteins nephrin and podocin.

  5. Modulation of the immune response in rheumatoid arthritis with strategically released rapamycin.

    Science.gov (United States)

    Shao, Ping; Ma, Linxiao; Ren, Yile; Liu, Huijie

    2017-10-01

    Rheumatoid arthritis (RA) is a chronic inflammatory disease, which is associated with symptoms, including synovial membrane inflammatory pain, joint synovitis and stiffness. However, there are no effective methods available to cure this disease. In the present study, rapamycin was used to modulate immunity in RA. To limit the cytotoxicity of rapamycin, rapamycin was loaded into well‑characterized biocompatible nanoparticles. In vitro, rapamycin particles downregulated the activation of dendritic cell surface markers, including CD80+ and CD40+, upon interacting with macrophages. The rapamycin particles reduced the secretion of inflammatory cytokines, including interleukin (IL)‑6, tumor necrosis factor (TNF) and IL‑1β, which are characteristic of RA. In vivo, the rapamycin particles decreased the symptoms of RA in mice, and the production of inflammatory cytokines was associated with the occurrence of RA. The present study partially revealed the interactions between rapamycin and two types of immune cell in RA disease, and may potentially offer a solution to improve the treatment of RA.

  6. Cancer Nanomedicines Stabilized by π-π Stacking between Heterodimeric Prodrugs Enable Exceptionally High Drug Loading Capacity and Safer Delivery of Drug Combinations.

    Science.gov (United States)

    Wang, Hangxiang; Chen, Jianmei; Xu, Chang; Shi, Linlin; Tayier, Munire; Zhou, Jiahui; Zhang, Jun; Wu, Jiaping; Ye, Zhijian; Fang, Tao; Han, Weidong

    2017-01-01

    Combination therapy using distinct mode-of-action drugs has sparked a rapidly growing interest because this paradigm holds promise for improving the therapeutic efficacy of anticancer therapy. However, the current drug combination therapy refers to administering individual drugs together, which is far from a perfect regimen for cancer patients. The aim of this work was to demonstrate that synergistic delivery of two chemotherapeutic drugs in a single nanoparticle reservoir could be achieved through the rational chemical ligation of the drugs followed by supramolecular nano-assembly via blending of the drugs with a minimal amount of matrix. Choosing 7-ethyl-10-hydroxycamptothecin and taxanes, which are rich in aromatic structures, as model compounds, we show that the heterodimeric conjugates of the two agents are miscible with lipids to form systemically injectable nanomedicines. The compatibility between the prodrug conjugates and lipid carriers is substantially augmented by the intermolecular π-π stacking and alleviated polarity, thus enabling an exceptionally high drug loading (DL) capacity (~92%) and a gratifyingly long drug retention time within the micellar core. We further observed superior therapeutic outcomes in a mouse tumor model without detecting accompanying systemic toxicity. This structure-based, self-assembled cancer nanomedicine increased the potency and drug tolerability in animals and thus offers a robust strategy for simultaneously formulating two or more drugs in single nanovehicles.

  7. Rapamycin regulates autophagy and cell adhesion in induced pluripotent stem cells

    Directory of Open Access Journals (Sweden)

    Areechun Sotthibundhu

    2016-11-01

    Full Text Available Abstract Background Cellular reprogramming is a stressful process, which requires cells to engulf somatic features and produce and maintain stemness machineries. Autophagy is a process to degrade unwanted proteins and is required for the derivation of induced pluripotent stem cells (iPSCs. However, the role of autophagy during iPSC maintenance remains undefined. Methods Human iPSCs were investigated by microscopy, immunofluorescence, and immunoblotting to detect autophagy machinery. Cells were treated with rapamycin to activate autophagy and with bafilomycin to block autophagy during iPSC maintenance. High concentrations of rapamycin treatment unexpectedly resulted in spontaneous formation of round floating spheres of uniform size, which were analyzed for differentiation into three germ layers. Mass spectrometry was deployed to reveal altered protein expression and pathways associated with rapamycin treatment. Results We demonstrate that human iPSCs express high basal levels of autophagy, including key components of APMKα, ULK1/2, BECLIN-1, ATG13, ATG101, ATG12, ATG3, ATG5, and LC3B. Block of autophagy by bafilomycin induces iPSC death and rapamycin attenuates the bafilomycin effect. Rapamycin treatment upregulates autophagy in iPSCs in a dose/time-dependent manner. High concentration of rapamycin reduces NANOG expression and induces spontaneous formation of round and uniformly sized embryoid bodies (EBs with accelerated differentiation into three germ layers. Mass spectrometry analysis identifies actin cytoskeleton and adherens junctions as the major targets of rapamycin in mediating iPSC detachment and differentiation. Conclusions High levels of basal autophagy activity are present during iPSC derivation and maintenance. Rapamycin alters expression of actin cytoskeleton and adherens junctions, induces uniform EB formation, and accelerates differentiation. IPSCs are sensitive to enzyme dissociation and require a lengthy differentiation time

  8. Heterodimerization of Dibenzodiazepinone-Type Muscarinic Acetylcholine Receptor Ligands Leads to Increased M2R Affinity and Selectivity

    OpenAIRE

    She, Xueke; Pegoli, Andrea; Mayr, Judith; Hübner, Harald; Bernhardt, Günther; Gmeiner, Peter; Keller, Max

    2017-01-01

    In search for selective ligands for the muscarinic acetylcholine receptor (MR) subtype M2, the dimeric ligand approach, that is combining two pharmacophores in one and the same molecule, was pursued. Different types (agonists, antagonists, orthosteric, and allosteric) of monomeric MR ligands were combined by various linkers with a dibenzodiazepinone-type MR antagonist, affording five types of heterodimeric compounds (“DIBA-xanomeline,” “DIBA-TBPB,” “DIBA-77-LH-28-1,” “DIBA-propantheline,” and...

  9. Regression of Subependymal Giant Cell Astrocytoma With Rapamycin in Tuberous Sclerosis Complex

    Science.gov (United States)

    Koenig, Mary Kay; Butler, Ian J.; Northrup, Hope

    2011-01-01

    The authors present a 21-year-old woman who has been receiving rapamycin for 5 months for bilateral subependymal giant cell astrocytomas. The patient was started at a dose of 0.2 mg/kg/day. Levels were maintained between 11 and 13 ng/mL. Magnetic resonance imaging of the brain 2½ months after initiating rapamycin demonstrated a decrease in size of both astrocytomas (11 to 7.5 mm on the right and 8 to 5 mm on the left). Further studies are needed with prolonged observation to confirm these findings, determine the length of necessary treatment, and evaluate recurrence risk after discontinuation of rapamycin. PMID:18952591

  10. Comparison of rapamycin schedules in mice on high-fat diet.

    Science.gov (United States)

    Leontieva, Olga V; Paszkiewicz, Geraldine M; Blagosklonny, Mikhail V

    2014-01-01

    At a wide range of doses, rapamycin extends life span in mice. It was shown that intraperitoneal injections (i.p.) of rapamycin prevent weight gain in mice on high-fat diet (HFD). We further investigated the effect of rapamycin on weight gain in female C57BL/6 mice on HFD started at the age of 7.5 months. By the age of 16 and 23 months, mice on HFD weighed significantly more (52 vs 33 g; p = 0.0001 and 70 vs 38 g; p applications are discussed.

  11. Rapamycin Loaded Solid Lipid Nanoparticles as a New Tool to Deliver mTOR Inhibitors: Formulation and in Vitro Characterization.

    Science.gov (United States)

    Polchi, Alice; Magini, Alessandro; Mazuryk, Jarosław; Tancini, Brunella; Gapiński, Jacek; Patkowski, Adam; Giovagnoli, Stefano; Emiliani, Carla

    2016-05-09

    Recently, the use of mammalian target of rapamycin (mTOR) inhibitors, in particular rapamycin (Rp), has been suggested to improve the treatment of neurodegenerative diseases. However, as Rp is a strong immunosuppressant, specific delivery to the brain has been postulated to avoid systemic exposure. In this work, we fabricated new Rp loaded solid lipid nanoparticles (Rp-SLN) stabilized with polysorbate 80 (PS80), comparing two different methods and lipids. The formulations were characterized by differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR), wide angle X-ray scattering (WAXS), cryo-transmission electron microscopy (cryo-TEM), dynamic light scattering (DLS) and particle tracking. In vitro release and short-term stability were assessed. Biological behavior of Rp-SLN was tested in SH-SY5Y neuroblastoma cells. The inhibition of mTOR complex 1 (mTORC1) was evaluated over time by a pulse-chase study compared to free Rp and Rp nanocrystals. Compritol Rp-SLN resulted more stable and possessing proper size and surface properties with respect to cetyl palmitate Rp-SLN. Rapamycin was entrapped in an amorphous form in the solid lipid matrix that showed partial crystallinity with stable Lβ, sub-Lα and Lβ' arrangements. PS80 was stably anchored on particle surface. No drug release was observed over 24 h and Rp-SLN had a higher cell uptake and a more sustained effect over a week. The mTORC1 inhibition was higher with Rp-SLN. Overall, compritol Rp-SLN show suitable characteristics and stability to be considered for further investigation as Rp brain delivery system.

  12. Rapamycin Loaded Solid Lipid Nanoparticles as a New Tool to Deliver mTOR Inhibitors: Formulation and in Vitro Characterization

    Directory of Open Access Journals (Sweden)

    Alice Polchi

    2016-05-01

    Full Text Available Recently, the use of mammalian target of rapamycin (mTOR inhibitors, in particular rapamycin (Rp, has been suggested to improve the treatment of neurodegenerative diseases. However, as Rp is a strong immunosuppressant, specific delivery to the brain has been postulated to avoid systemic exposure. In this work, we fabricated new Rp loaded solid lipid nanoparticles (Rp-SLN stabilized with polysorbate 80 (PS80, comparing two different methods and lipids. The formulations were characterized by differential scanning calorimetry (DSC, nuclear magnetic resonance (NMR, wide angle X-ray scattering (WAXS, cryo-transmission electron microscopy (cryo-TEM, dynamic light scattering (DLS and particle tracking. In vitro release and short-term stability were assessed. Biological behavior of Rp-SLN was tested in SH-SY5Y neuroblastoma cells. The inhibition of mTOR complex 1 (mTORC1 was evaluated over time by a pulse-chase study compared to free Rp and Rp nanocrystals. Compritol Rp-SLN resulted more stable and possessing proper size and surface properties with respect to cetyl palmitate Rp-SLN. Rapamycin was entrapped in an amorphous form in the solid lipid matrix that showed partial crystallinity with stable Lβ, sub-Lα and Lβ′ arrangements. PS80 was stably anchored on particle surface. No drug release was observed over 24 h and Rp-SLN had a higher cell uptake and a more sustained effect over a week. The mTORC1 inhibition was higher with Rp-SLN. Overall, compritol Rp-SLN show suitable characteristics and stability to be considered for further investigation as Rp brain delivery system.

  13. Chronic treatment with novel nanoformulated micelles of rapamycin, Rapatar, protects diabetic heart against ischaemia/reperfusion injury.

    Science.gov (United States)

    Samidurai, Arun; Salloum, Fadi N; Durrant, David; Chernova, Olga B; Kukreja, Rakesh C; Das, Anindita

    2017-10-01

    Enhanced mammalian target of rapamycin (mTOR) signalling contributes to the pathogenesis of diabetes and plays a critical role in myocardial ischaemia/reperfusion (I/R) injury. Rapatar is a novel nanoformulated micellar of rapamycin, a putative inhibitor of mTOR that has been rationally designed to increase water solubility of rapamycin to facilitate p.o. administration and enhance bioavailability. We examined the effect of Rapatar on the metabolic status and protection against myocardial I/R injury in type 2 diabetic mice. Adult male db/db mice were treated daily for 10 weeks with Rapatar (0.75 mg·kg-1 ·day-1 , p.o.) or vehicle. Isolated hearts were connected to a Langendorff perfusion system and subjected to global ischaemia (30 min) and reperfusion (1 h). Rapatar reduced fasting plasma glucose and triglyceride levels, prevented the gain in body weight and also improved glucose tolerance and insulin sensitivity in db/db mice compared with control. Cardiac function was improved following Rapatar treatment in db/db mice. Myocardial infarct size was reduced in Rapatar-treated mice with improved post-ischaemic rate-force product. Western blot analyses demonstrated a significant inhibition of phosphorylation of ribosomal protein S6 (downstream target of mTORC1), but not Akt (Ser473 , target of mTORC2) following chronic treatment with Rapatar. Rapatar also induced phosphorylation of AMPK, STAT3, ERK1/2 and glycogen synthase kinase 3β, without interfering with phosphorylation of p38. Our studies indicate that chronic treatment with Rapatar improves metabolic status and cardiac function with a reduction of infarct size following myocardial I/R injury in diabetic mice. © 2017 The British Pharmacological Society.

  14. A One-Pot Chemically Cleavable Bis-Linker Tether Strategy for the Synthesis of Heterodimeric Peptides.

    Science.gov (United States)

    Patil, Nitin A; Tailhades, Julien; Karas, John A; Separovic, Frances; Wade, John D; Hossain, Mohammed Akhter

    2016-11-14

    Heterodimeric peptides linked by disulfide bonds are attractive drug targets. However, their chemical assembly can be tedious, time-consuming, and low yielding. Inspired by the cellular synthesis of pro-insulin in which the two constituent peptide chains are expressed as a single-chain precursor separated by a connecting C-peptide, we have developed a novel chemically cleavable bis-linker tether which allows the convenient assembly of two peptide chains as a single "pro"-peptide on the same solid support. Following the peptide cleavage and post-synthetic modifications, this bis-linker tether can be removed in one-step by chemical means. This method was used to synthesize a drug delivery-cargo conjugate, TAT-PKCi peptide, and a two-disulfide bridged heterodimeric peptide, thionin (7-19)-(24-32R), a thionin analogue. To our knowledge, this is the first report of a one-pot chemically cleavable bis-linker strategy for the facile synthesis of cross-bridged two-chain peptides. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Bioelectronic tongue using heterodimeric human taste receptor for the discrimination of sweeteners with human-like performance.

    Science.gov (United States)

    Song, Hyun Seok; Jin, Hye Jun; Ahn, Sae Ryun; Kim, Daesan; Lee, Sang Hun; Kim, Un-Kyung; Simons, Christopher T; Hong, Seunghun; Park, Tai Hyun

    2014-10-28

    The sense of taste helps humans to obtain information and form a picture of the world by recognizing chemicals in their environments. Over the past decade, large advances have been made in understanding the mechanisms of taste detection and mimicking its capability using artificial sensor devices. However, the detection capability of previous artificial taste sensors has been far inferior to that of animal tongues, in terms of its sensitivity and selectivity. Herein, we developed a bioelectronic tongue using heterodimeric human sweet taste receptors for the detection and discrimination of sweeteners with human-like performance, where single-walled carbon nanotube field-effect transistors were functionalized with nanovesicles containing human sweet taste receptors and used to detect the binding of sweeteners to the taste receptors. The receptors are heterodimeric G-protein-coupled receptors (GPCRs) composed of human taste receptor type 1 member 2 (hTAS1R2) and human taste receptor type 1 member 3 (hTAS1R3), which have multiple binding sites and allow a human tongue-like broad selectivity for the detection of sweeteners. This nanovesicle-based bioelectronic tongue can be a powerful tool for the detection of sweeteners as an alternative to labor-intensive and time-consuming cell-based assays and the sensory evaluation panels used in the food and beverage industry. Furthermore, this study also allows the artificial sensor to exam the functional activity of dimeric GPCRs.

  16. Prediction of heterodimeric protein complexes from weighted protein-protein interaction networks using novel features and kernel functions.

    Directory of Open Access Journals (Sweden)

    Peiying Ruan

    Full Text Available Since many proteins express their functional activity by interacting with other proteins and forming protein complexes, it is very useful to identify sets of proteins that form complexes. For that purpose, many prediction methods for protein complexes from protein-protein interactions have been developed such as MCL, MCODE, RNSC, PCP, RRW, and NWE. These methods have dealt with only complexes with size of more than three because the methods often are based on some density of subgraphs. However, heterodimeric protein complexes that consist of two distinct proteins occupy a large part according to several comprehensive databases of known complexes. In this paper, we propose several feature space mappings from protein-protein interaction data, in which each interaction is weighted based on reliability. Furthermore, we make use of prior knowledge on protein domains to develop feature space mappings, domain composition kernel and its combination kernel with our proposed features. We perform ten-fold cross-validation computational experiments. These results suggest that our proposed kernel considerably outperforms the naive Bayes-based method, which is the best existing method for predicting heterodimeric protein complexes.

  17. Rapamycin sensitizes T-ALL cells to dexamethasone-induced apoptosis

    Directory of Open Access Journals (Sweden)

    Mu Dezhi

    2010-11-01

    Full Text Available Abstract Background Glucocorticoid (GC resistance is frequently seen in acute lymphoblastic leukemia of T-cell lineage (T-ALL. In this study we investigate the potential and mechanism of using rapamycin to restore the sensitivity of GC-resistant T-ALL cells to dexamethasone (Dex treatment. Methods Cell proliferation was detected by 3-(4,5-dimethylthiazol-2-yl- 2,5-diphenyltetrazolium bromide (MTT assay. Fluorescence-activated cell sorting (FACS analysis was used to analyze apoptosis and cell cycles. Western blot analysis was performed to test the expression of the downstream effector proteins of mammalian target of rapamycin (mTOR, the cell cycle regulatory proteins, and apoptosis associated proteins. Results 10 nM rapamycin markedly increased GC sensitivity in GC-resistant T-ALL cells and this effect was mediated, at least in part, by inhibition of mTOR signaling pathway. Cell cycle arrest was associated with modulation of G1-S phase regulators. Both rapamycin and Dex can induce up-regulation of cyclin-dependent kinase (CDK inhibitors of p21 and p27 and co-treatment of rapamycin with Dex resulted in a synergistic induction of their expressions. Rapamycin did not obviously affect the expression of cyclin A, whereas Dex induced cyclin A expression. Rapamycin prevented Dex-induced expression of cyclin A. Rapamycin had a stronger inhibition of cyclin D1 expression than Dex. Rapamycin enhanced GC-induced apoptosis and this was not achieved by modulation of glucocorticoid receptor (GR expression, but synergistically up-regulation of pro-apoptotic proteins like caspase-3, Bax, and Bim, and down-regulation of anti-apoptotic protein of Mcl-1. Conclusion Our data suggests that rapamycin can effectively reverse GC resistance in T-ALL and this effect is achieved by inducing cell cycles arrested at G0/G1 phase and activating the intrinsic apoptotic program. Therefore, combination of mTOR inhibitor rapamycin with GC containing protocol might be an attracting

  18. Rapamycin pharmacokinetic and pharmacodynamic relationships in osteosarcoma: a comparative oncology study in dogs.

    Directory of Open Access Journals (Sweden)

    Melissa C Paoloni

    2010-06-01

    Full Text Available Signaling through the mTOR pathway contributes to growth, progression and chemoresistance of several cancers. Accordingly, inhibitors have been developed as potentially valuable therapeutics. Their optimal development requires consideration of dose, regimen, biomarkers and a rationale for their use in combination with other agents. Using the infrastructure of the Comparative Oncology Trials Consortium many of these complex questions were asked within a relevant population of dogs with osteosarcoma to inform the development of mTOR inhibitors for future use in pediatric osteosarcoma patients.This prospective dose escalation study of a parenteral formulation of rapamycin sought to define a safe, pharmacokinetically relevant, and pharmacodynamically active dose of rapamycin in dogs with appendicular osteosarcoma. Dogs entered into dose cohorts consisting of 3 dogs/cohort. Dogs underwent a pre-treatment tumor biopsy and collection of baseline PBMC. Dogs received a single intramuscular dose of rapamycin and underwent 48-hour whole blood pharmacokinetic sampling. Additionally, daily intramuscular doses of rapamycin were administered for 7 days with blood rapamycin trough levels collected on Day 8, 9 and 15. At Day 8 post-treatment collection of tumor and PBMC were obtained. No maximally tolerated dose of rapamycin was attained through escalation to the maximal planned dose of 0.08 mg/kg (2.5 mg/30 kg dog. Pharmacokinetic analysis revealed a dose-dependent exposure. In all cohorts modulation of the mTOR pathway in tumor and PBMC (pS6RP/S6RP was demonstrated. No change in pAKT/AKT was seen in tumor samples following rapamycin therapy.Rapamycin may be safely administered to dogs and can yield therapeutic exposures. Modulation pS6RP/S6RP in tumor tissue and PBMCs was not dependent on dose. Results from this study confirm that the dog may be included in the translational development of rapamycin and potentially other mTOR inhibitors. Ongoing studies of

  19. Crystallization and preliminary X-ray diffraction analysis of the small subunit of the heterodimeric restriction endonuclease R.BspD6I

    Energy Technology Data Exchange (ETDEWEB)

    Kachalova, Galina S. [Max-Planck Unit for Structural Molecular Biology, Hamburg 22607 (Germany); Yunusova, Alfiya K.; Artyukh, Rimma I.; Rogulin, Eugeny A.; Perevyazova, Tatyana A.; Zheleznaya, Ludmila A. [Institute of Theoretical and Experimental Biophysics, Pushchino 142290 (Russian Federation); Matvienko, Nickolay I. [Institute of Protein Research, Pushchino 14229 (Russian Federation); Bartunik, Hans D., E-mail: bartunik@mpghdb.desy.de [Max-Planck Unit for Structural Molecular Biology, Hamburg 22607 (Germany)

    2007-09-01

    The crystallization of the small subunit of the heterodimeric restriction endonuclease R.BspD6I and diffraction data collection to 1.5 Å resolution are reported. The heterodimeric restriction endonuclease R.BspD6I is composed of a small subunit with a cleavage site and a large subunit, containing a recognition domain and a cleavage domain, that may function separately as a monomeric nicking endonuclease. Here, the crystallization of the small subunit and diffraction data collection to 1.5 Å resolution are reported.

  20. The effect of Bortezomib and Rapamycin on Telomerase Activity in Mantle Cell Lymphoma

    Directory of Open Access Journals (Sweden)

    Orit Uziel

    2014-12-01

    In the light of the crucial role of telomerase in cancer cells, it was important to characterize the possible relations between telomerase and bortezomib and to distinguish the biochemical mechanisms of its regulation and its interactions with other signal transduction inhibitors such as rapamycin. The results of this work encourage the in vivo examination of the therapeutic potential of the combination of bortezomib and rapamycin in Mantle Cell Lymphoma patients.

  1. Rapamycin increases fetal hemoglobin and ameliorates the nociception phenotype in sickle cell mice.

    Science.gov (United States)

    Khaibullina, Alfia; Almeida, Luis E F; Wang, Li; Kamimura, Sayuri; Wong, Edward C C; Nouraie, Mehdi; Maric, Irina; Albani, Sarah; Finkel, Julia; Quezado, Zenaide M N

    2015-12-01

    Fetal hemoglobin-inducing therapies are disease-modifying and ameliorate the pain phenotype in sickle cell disease (SCD). Rapamycin, a mammalian target of rapamycin (mTOR) inhibitor, increases HbF in erythroid precursor cells in vitro. We hypothesized that rapamycin would increase HbF levels and improve nociception phenotype in SCD mice. We used sine-wave electrical stimulation to examine nocifensive phenotype and evaluate myelinated [2000Hz (Aβ-fiber) and 250Hz (Aδ-fiber)] and unmyelinated (5Hz C-fibers)] sensory fiber function. Rapamycin significantly increased γ-globin mRNA and HbF levels [+2.3% (0.7, 3.9), mean increase (95% confidence interval, CI), p=0.006]. In homozygous (sickling) mice, long- (16 weeks), but not short-term (6 weeks), rapamycin treatment increased 2000Hz and 250Hz current thresholds in a pattern that varied according to sex. In male, but not female mice, rapamycin (compared with vehicle) was associated with increases in 2000Hz [21Units (7, 35), mean difference (95% CI), p=0.009 for sex∗treatment interaction] and 250Hz [9Units (1, 16), p=0.01] current thresholds. In rapamycin-treated homozygotes, HbF levels directly correlated with myelinated [2000Hz(Aβ-fiber, r=0.58, p=0.01) and 250Hz(Aδ-fiber, r=0.6, p=0.01)] but not unmyelinated sensory fiber current thresholds. These findings suggest that in SCD mice, rapamycin increases HbF and modulates current thresholds of myelinated fibers. Therefore, mTOR signaling might be implicated in the pathobiology of SCD. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Differential Effects of Rapamycin and Dexamethasone in Mouse Models of Established Allergic Asthma

    Science.gov (United States)

    Mushaben, Elizabeth M.; Brandt, Eric B.; Hershey, Gurjit K. Khurana; Le Cras, Timothy D.

    2013-01-01

    The mammalian target of rapamycin (mTOR) plays an important role in cell growth/differentiation, integrating environmental cues, and regulating immune responses. Our lab previously demonstrated that inhibition of mTOR with rapamycin prevented house dust mite (HDM)-induced allergic asthma in mice. Here, we utilized two treatment protocols to investigate whether rapamycin, compared to the steroid, dexamethasone, could inhibit allergic responses during the later stages of the disease process, namely allergen re-exposure and/or during progression of chronic allergic disease. In protocol 1, BALB/c mice were sensitized to HDM (three i.p. injections) and administered two intranasal HDM exposures. After 6 weeks of rest/recovery, mice were re-exposed to HDM while being treated with rapamycin or dexamethasone. In protocol 2, mice were exposed to HDM for 3 or 6 weeks and treated with rapamycin or dexamethasone during weeks 4–6. Characteristic features of allergic asthma, including IgE, goblet cells, airway hyperreactivity (AHR), inflammatory cells, cytokines/chemokines, and T cell responses were assessed. In protocol 1, both rapamycin and dexamethasone suppressed goblet cells and total CD4+ T cells including activated, effector, and regulatory T cells in the lung tissue, with no effect on AHR or total inflammatory cell numbers in the bronchoalveolar lavage fluid. Rapamycin also suppressed IgE, although IL-4 and eotaxin 1 levels were augmented. In protocol 2, both drugs suppressed total CD4+ T cells, including activated, effector, and regulatory T cells and IgE levels. IL-4, eotaxin, and inflammatory cell numbers were increased after rapamycin and no effect on AHR was observed. Dexamethasone suppressed inflammatory cell numbers, especially eosinophils, but had limited effects on AHR. We conclude that while mTOR signaling is critical during the early phases of allergic asthma, its role is much more limited once disease is established. PMID:23349887

  3. Combinatorial Antitumor Effect of Rapamycin and β-Elemene in Follicular Thyroid Cancer Cells

    Directory of Open Access Journals (Sweden)

    Jun Zhou

    2016-01-01

    Full Text Available Background. mTOR signaling would be a promising target for thyroid cancer therapy. However, in clinical trials, objective response rate with mTOR inhibitor monotherapy in most cancer types was modest. A new focus on development of combinatorial strategies with rapalogs is increasing. Objective. Investigating the combinatorial antitumor effect of rapamycin and β-elemene in follicular thyroid cancer cells. Methods. MTT assay was used to determine the FTC-133 cell proliferation after culturing with rapamycin and/or β-elemene. To analyze their combinatorial effect, immunoblotting was performed to analyze the activation status of AKT. Moreover, β-elemene attenuated rapamycin-induced immunosuppression was tested in mice. Results. Combination of rapamycin and β-elemene exerted significant synergistic antiproliferative effects in FTC-133 cell lines in vitro, based on inhibiting the AKT feedback activation induced by rapamycin. In vivo, the β-elemene could attenuate rapamycin-induced immunosuppression via reversing imbalance of Treg/Th17, with the underlying mechanism needed to be declared. Conclusions. We demonstrate that the novel combination of mTOR inhibitor with β-elemene synergistically attenuates tumor cell growth in follicular thyroid cancer, which requires additional preclinical validation.

  4. Rapamycin reversal of VEGF-C-driven lymphatic anomalies in the respiratory tract.

    Science.gov (United States)

    Baluk, Peter; Yao, Li-Chin; Flores, Julio C; Choi, Dongwon; Hong, Young-Kwon; McDonald, Donald M

    2017-08-17

    Lymphatic malformations are serious but poorly understood conditions that present therapeutic challenges. The goal of this study was to compare strategies for inducing regression of abnormal lymphatics and explore underlying mechanisms. CCSP-rtTA/tetO-VEGF-C mice, in which doxycycline regulates VEGF-C expression in the airway epithelium, were used as a model of pulmonary lymphangiectasia. After doxycycline was stopped, VEGF-C expression returned to normal, but lymphangiectasia persisted for at least 9 months. Inhibition of VEGFR-2/VEGFR-3 signaling, Notch, β-adrenergic receptors, or autophagy and antiinflammatory steroids had no noticeable effect on the amount or severity of lymphangiectasia. However, rapamycin inhibition of mTOR reduced lymphangiectasia by 76% within 7 days without affecting normal lymphatics. Efficacy of rapamycin was not increased by coadministration with the other agents. In prevention trials, rapamycin suppressed VEGF-C-driven mTOR phosphorylation and lymphatic endothelial cell sprouting and proliferation. However, in reversal trials, no lymphatic endothelial cell proliferation was present to block in established lymphangiectasia, and rapamycin did not increase caspase-dependent apoptosis. However, rapamycin potently suppressed Prox1 and VEGFR-3. These experiments revealed that lymphangiectasia is remarkably resistant to regression but is responsive to rapamycin, which rapidly reduces and normalizes the abnormal lymphatics without affecting normal lymphatics.

  5. Acute and chronic rapamycin use in patients with Fibrodysplasia Ossificans Progressiva: A report of two cases.

    Science.gov (United States)

    Kaplan, Frederick S; Zeitlin, Leonid; Dunn, Stephen P; Benor, Shira; Hagin, David; Al Mukaddam, Mona; Pignolo, Robert J

    2017-12-11

    Fibrodysplasia Ossificans Progressiva (FOP) is an ultrarare genetic disorder of progressive, disabling heterotopic ossification for which there is presently no definitive treatment. Several recent studies in genetic mouse models of FOP support involvement of the mechanistic target of rapamycin complex 1 (mTORC1) pathway in the pathophysiology of FOP and propose the repurposed use of rapamycin, an inhibitor of mTORC1 signaling in clinical trials for the management of FOP. Here we report two patients with the classic FOP mutation who received rapamycin-one for four months on a compassionate basis for treatment of acute flare-ups of the neck and back that were refractory to corticosteroid therapy-and the other for 18years for chronic immunosuppression following liver transplantation for intercurrent cytomegalovirus infection. In both patients, FOP progressed despite the use of rapamycin. This report highlights the real-world use of rapamycin in two FOP patients and provides insight into the use of rapamycin in clinical trials for the management of FOP. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Rapamycin Regulates Bleomycin-Induced Lung Damage in SP-C-Deficient Mice

    Directory of Open Access Journals (Sweden)

    Satish K. Madala

    2011-01-01

    Full Text Available Injury to the distal respiratory epithelium has been implicated as an underlying cause of idiopathic lung diseases. Mutations that result in SP-C deficiencies are linked to a small subset of spontaneous and familial cases of interstitial lung disease (ILD and interstitial pulmonary fibrosis (IPF. Gene-targeted mice that lack SP-C (−/− develop an irregular ILD-like disease with age and are a model of the human SP-C related disease. In the current study, we investigated whether rapamycin could ameliorate bleomycin-induced fibrosis in the lungs of −/− mice. +/+ and −/− mice were exposed to bleomycin with either preventative administration of rapamycin or therapeutic administration beginning eight days after the bleomycin injury. Rapamycin-treatment increased weight loss and decreased survival of bleomycin-treated +/+ and −/− mice. Rapamycin did not reduce the fibrotic disease in the prophylactic or rescue experiments of either genotype of mice. Further, rapamycin treatment augmented airway resistance and reduced lung compliance of bleomycin-treated −/− mice. Rapamycin treatment was associated with an increased expression of profibrotic Th2 cytokines and reduced expression of INF-γ. These findings indicate that novel therapeutics will be required to treat individuals with SP-C deficient ILD/IPF.

  7. Targeting human medulloblastoma: oncolytic virotherapy with myxoma virus is enhanced by rapamycin.

    Science.gov (United States)

    Lun, Xue Qing; Zhou, Hongyuan; Alain, Tommy; Sun, Beichen; Wang, Limei; Barrett, John W; Stanford, Marianne M; McFadden, Grant; Bell, John; Senger, Donna L; Forsyth, Peter A

    2007-09-15

    We have shown previously the oncolytic potential of myxoma virus in a murine xenograft model of human glioma. Here, we show that myxoma virus used alone or in combination with rapamycin is effective and safe when used in experimental models of medulloblastoma in vitro and in vivo. Nine of 10 medulloblastoma cell lines tested were susceptible to lethal myxoma virus infection, and pretreatment of cells with rapamycin increased the extent of in vitro oncolysis. Intratumoral injection of live myxoma virus when compared with control inactivated virus prolonged survival in D341 and Daoy orthotopic human medulloblastoma xenograft mouse models [D341 median survival: 21 versus 12.5 days; P = 0.0008; Daoy median survival: not reached (three of five mice apparently "cured" after 223 days) versus 75 days; P = 0.0021]. Rapamycin increased the extent of viral oncolysis, "curing" most Daoy tumor-bearing mice and reducing or eliminating spinal cord and ventricle metastases. Rapamycin enhanced tumor-specific myxoma virus replication in vivo and prolonged survival of D341 tumor-bearing mice (median survival of mice treated with live virus (LV) and rapamycin, versus LV alone, versus rapamycin alone, versus inactivated virus: 25 days versus 19, 13, and 11 days, respectively; P myxoma virus oncolysis. These observations suggest that myxoma virus may be an effective oncolytic agent against medulloblastoma and that combination therapy with signaling inhibitors that modulate activity of the phosphatidylinositol 3-kinase/Akt pathway will further enhance the oncolytic potential of myxoma virus.

  8. Rapamycin inhibits mTOR/p70S6K activation in CA3 region of the hippocampus of the rat and impairs long term memory.

    Science.gov (United States)

    Lana, D; Di Russo, J; Mello, T; Wenk, G L; Giovannini, M G

    2017-01-01

    The present study was aimed at establishing whether the mTOR pathway and its downstream effector p70S6K in CA3 pyramidal neurons are under the modulation of the cholinergic input to trigger the formation of long term memories, similar to what we demonstrated in CA1 hippocampus. We performed in vivo behavioral experiments using the step down inhibitory avoidance test in adult Wistar rats to evaluate memory formation under different conditions. We examined the effects of rapamycin, an inhibitor of mTORC1 formation, scopolamine, a muscarinic receptor antagonist or mecamylamine, a nicotinic receptor antagonist, on short and long term memory formation and on the functionality of the mTOR pathway. Acquisition was conducted 30min after i.c.v. injection of rapamycin. Recall testing was performed 1h, 4h or 24h after acquisition. We found that (1) mTOR and p70S6K activation in CA3 pyramidal neurons were involved in long term memory formation; (2) rapamycin significantly inhibited mTOR and of p70S6K activation at 4h, and long term memory impairment 24h after acquisition; (3) scopolamine impaired short but not long term memory, with an early increase of mTOR/p70S6K activation at 1h followed by stabilization at longer times; (4) mecamylamine and scopolamine co-administration impaired short term memory at 1h and 4h and reduced the scopolamine-induced increase of mTOR/p70S6K activation at 1h and 4h; (5) mecamylamine and scopolamine treatment did not impair long term memory formation; (6) unexpectedly, rapamycin increased mTORC2 activation in microglial cells. Our results demonstrate that in CA3 pyramidal neurons the mTOR/p70S6K pathway is under the modulation of the cholinergic system and is involved in long-term memory encoding, and are consistent with the hypothesis that the CA3 region of the hippocampus is involved in memory mechanisms based on rapid, one-trial object-place learning and recall. Furthermore, our results are in accordance with previous reports that selective

  9. Target of rapamycin activation predicts lifespan in fruit flies.

    Science.gov (United States)

    Scialò, Filippo; Sriram, Ashwin; Naudí, Alba; Ayala, Victoria; Jové, Mariona; Pamplona, Reinald; Sanz, Alberto

    2015-01-01

    Aging and age-related diseases are one of the most important health issues that the world will confront during the 21(st) century. Only by understanding the proximal causes will we be able to find treatments to reduce or delay the onset of degenerative diseases associated with aging. Currently, the prevalent paradigm in the field is the accumulation of damage. However, a new theory that proposes an alternative explanation is gaining momentum. The hyperfunction theory proposes that aging is not a consequence of a wear and tear process, but a result of the continuation of developmental programs during adulthood. Here we use Drosophila melanogaster, where evidence supporting both paradigms has been reported, to identify which parameters that have been previously related with lifespan best predict the rate of aging in wild type flies cultured at different temperatures. We find that mitochondrial function and mitochondrial reactive oxygen species (mtROS) generation correlates with metabolic rate, but not with the rate of aging. Importantly, we find that activation of nutrient sensing pathways (i.e. insulin-PI3K/Target of rapamycin (Tor) pathway) correlates with lifespan, but not with metabolic rate. Our results, dissociate metabolic rate and lifespan in wild type flies and instead link nutrient sensing signaling with longevity as predicted by the hyperfunction theory.

  10. [Effects of mTOR Inhibitor Rapamycin on Burkitt's Lymphoma Cells].

    Science.gov (United States)

    Zhou, Lun-Huan; Zhu, Xiong-Peng; Xiao, Hui-Fang; Xin, Peng-Liang; Li, Chun-Tuan

    2017-10-01

    To explore the effects of mTOR inhibitor rapamycin on proliferation, cell cycle and apoptosis of Burkitt's lymphoma cell line Raji and CA46 cells and its mechanism, so as to provide the experimental evidence for a therapeutic target of Burkitt's lymphoma. 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide(MTT) assay was performed to assess the inhibitory effect of rapamycin on proliferation of Burkitt's lymphoma cell line Raji and CA46 cells. The cell cycle distribution of Raji and CA46 cells was analyzed by flow cytometry with propidium iodide(PI) single staining. The cell apoptosis of Raji and CA46 cells was analyzed by flow cytometry with FITC Annexin V+PI double staining. The expressions of RPS6, p-RPS6, survivin and caspase-3 proteins were detected by Western blot after treating with rapamycin. Rapamycin markedly inhibited the proliferation of both Raji and CA46 cells in a time- and concentration-dependent manners, showing good biological activity, the cell proliferation inhibition rate reached about 20% after treatment with 1 nmol/L rapamycin. After treatment with different concentrations of rapamycin for 24 and 48 hours, the proportion of both cells in G1/G0 phase in the treated groups was significantly increased in a time- and concentration-dependent manners in comparison with the solvent control group. With regard to the cells in S and G2/M phase, the decreased population was accompanied by the increase of G1/G0 phase cells. After treatment with 100 nmol/L rapamycin for 48 hours, both Raji and CA46 cells demonstrated an apparent apoptosis,especially late apoptosis by flow cytometry with Annexin V+PI staining. After treatment with rapamycin, the expression of p-RPS6 and survivin of Raji and CA46 cells was obviously down-regulated, the expression of caspase-3 was obviously up-regulated in a time- and dose-dependent manners. However, rapamycin did not obviously affect the expression of RPS6. The rapamycin can effectively inhibit cell proliferation

  11. Active Mechanistic Target of Rapamycin plays an ancillary rather than essential role in Zebrafish CNS axon regeneration

    Directory of Open Access Journals (Sweden)

    Heike eDiekmann

    2015-07-01

    Full Text Available The developmental decrease of the intrinsic regenerative ability of the mammalian central nervous system (CNS is associated with reduced activity of mechanistic target of rapamycin (mTOR in mature neurons such as retinal ganglion cells (RGCs. While mTOR activity is further decreased upon axonal injury, maintenance of its pre-injury level, for instance by genetic deletion of the phosphatase and tensin homolog (PTEN, markedly promotes axon regeneration in mammals. The current study now addressed the question whether active mTOR might generally play a central role in axon regeneration by analyzing its requirement in regeneration-competent zebrafish. Remarkably, regulation of mTOR activity after optic nerve injury in zebrafish is fundamentally different compared to mammals. Hardly any activity was detected in naïve RGCs, whereas it was markedly increased upon axotomy in vivo as well as in dissociated cell cultures. After a short burst, mTOR activity was quickly attenuated, which is contrary to the requirements for axon regeneration in mammals. Surprisingly, mTOR activity was not essential for axonal growth per se, but correlated with cytokine- and PTEN inhibitor-induced neurite extension in vitro. Moreover, inhibition of mTOR using rapamycin significantly reduced axonal regeneration in vivo and delayed functional recovery after optic nerve injury. Therefore, axotomy-induced mTOR activity is involved in CNS axon regeneration in zebrafish similar to mammals, although it plays an ancillary rather than essential role in this regeneration-competent species.

  12. Delayed and short course of rapamycin prevents organ rejection after allogeneic liver transplantation in rats.

    Science.gov (United States)

    Hamdani, Salim; Thiolat, Allan; Naserian, Sina; Grondin, Cynthia; Moutereau, Stéphane; Hulin, Anne; Calderaro, Julien; Grimbert, Philippe; Cohen, José Laurent; Azoulay, Daniel; Pilon, Caroline

    2017-10-14

    To test whether a delayed and short course of rapamycin would induce immunosuppressive effects following allogeneic orthotopic liver transplantation (OLT) in rats. Allogeneic OLTs were performed using Dark Agouti livers transplanted into Lewis recipients, and syngeneic OLTs were performed using the Lewis rat strain. Rapamycin (1 mg/kg per day) was administered by gavage from day 4 to day 11 post-transplantation. Lymphocyte cellular compartments were analyzed by flow cytometry in draining lymph nodes, non-draining lymph nodes and the spleen at days 11 and 42 in rapamycin-treated rats, untreated control rats and syngeneic grafted rats. Skin grafts from Dark agouti or from F344 RT were performed at day 30 on liver grafted rats treated with rapamycin. An 8-d course of rapamycin treatment initiated 4 d following transplantation resulted in the survival of grafted rats for more than 100 d. In contrast, untreated rats died of liver failure within 13 to 21 d. The analysis of the cellular compartment revealed an increase in two cellular subpopulations, specifically myeloid-derived suppressor cells (MDSCs) and CD8+CD45RClow T cells, without major modifications in the regulatory T cell (Treg) compartment in treated rats in the early stages after grafting. We evaluated the ability of treated rats to reject third-party allogeneic skin grafts to confirm their immune competence. In contrast, when skin was collected from rats syngeneic to the grafted liver, it was not rejected. Our results demonstrate that short and delayed rapamycin treatment allows for tolerance in allogeneic OLT. The results also allowed for the identification of the mechanisms of tolerance induced by rapamycin by identifying MDSCs and CD8+CD45RClow T cells as associated with the state of tolerance.

  13. Rapamycin is highly effective in murine models of immune-mediated bone marrow failure.

    Science.gov (United States)

    Feng, Xingmin; Lin, Zenghua; Sun, Wanling; Hollinger, Maile K; Desierto, Marie J; Keyvanfar, Keyvan; Malide, Daniela; Muranski, Pawel; Chen, Jichun; Young, Neal S

    2017-10-01

    Acquired aplastic anemia, the prototypical bone marrow failure disease, is characterized by pancytopenia and marrow hypoplasia. Most aplastic anemia patients respond to immunosuppressive therapy, usually with anti-thymocyte globulin and cyclosporine, but some relapse on cyclosporine withdrawal or require long-term administration of cyclosporine to maintain blood counts. In this study, we tested efficacy of rapamycin as a new or alternative treatment in mouse models of immune-mediated bone marrow failure. Rapamycin ameliorated pancytopenia, improved bone marrow cellularity, and extended animal survival in a manner comparable to the standard dose of cyclosporine. Rapamycin effectively reduced Th1 inflammatory cytokines interferon-γ and tumor necrosis factor-α, increased the Th2 cytokine interleukin-10, stimulated expansion of functional regulatory T cells, eliminated effector CD8+ T cells (notably T cells specific to target cells bearing minor histocompatibility antigen H60), and preserved hematopoietic stem and progenitor cells. Rapamycin, but not cyclosporine, reduced the proportion of memory and effector T cells and maintained a pool of naïve T cells. Cyclosporine increased cytoplasmic nuclear factor of activated T-cells-1 following T-cell receptor stimulation, whereas rapamycin suppressed phosphorylation of two key signaling molecules in the mammalian target of rapamycin pathway, S6 kinase and protein kinase B. In summary, rapamycin was an effective therapy in mouse models of immune-mediated bone marrow failure, acting through different mechanisms to cyclosporine. Its specific expansion of regulatory T cells and elimination of clonogenic CD8+ effectors support its potential clinical utility in the treatment of aplastic anemia. Copyright© 2017 Ferrata Storti Foundation.

  14. Making many from few: IL-12p40 as a model for the combinatorial assembly of heterodimeric cytokines.

    Science.gov (United States)

    Abdi, Kaveh; Singh, Nevil J

    2015-11-01

    How dendritic cells (DCs) gather information from the local milieu at a site of infection or injury and communicate this to influence adaptive immunity is not well understood. We and others have reported that soon after microbial encounter, DCs secrete the p40 subunit of IL-12, by itself, in a monomeric form. Based on recent data that this p40 monomer subsequently associates with p35 released from other cells to generate functional IL-12, we proposed that p40 can function as a DC-derived probe which samples the composition of the local milieu by looking for other binding partners. In this opinion, we discuss how such a sampling function might generate an elaborate combinatorial "code" of heterodimeric cytokines, capable of conveying location-specific information to cells downstream of DC activation, including NK and T cells. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Isolation of a novel thermolabile heterodimeric ribonuclease with antifungal and antiproliferative activities from roots of the sanchi ginseng Panax notoginseng.

    Science.gov (United States)

    Lam, S K; Ng, T B

    2001-07-13

    An isolation procedure, consisting of ion exchange chromatography on CM-Sepharose, affinity chromatography on Affi-gel blue gel, and fast protein liquid chromatography on Mono S, was utilized to purify a base-nonspecific, heterodimeric ribonuclease (RNase) with diverse activities from roots of the sanchi ginseng Panax notoginseng. The RNase is unique in that it consists of two different nonglycoprotein subunits with a molecular weight of 27 and 29 kDa, respectively. The latter subunit is characterized by an N-terminal sequence showing remarkable similarity to that of the bitter gourd RNase. The Panax notoginseng RNase demonstrates potent RNase and translation-inhibitory activities. In addition, it exhibits antiproliferative activity toward leukemia L1210 cells and antifungal activity against Physalospora piricola and Coprinus comatus. Its RNase activity is not heat-resistant, unlike most RNases which are thermostable. Copyright 2001 Academic Press.

  16. The Heterodimeric TWIST1-E12 Complex Drives the Oncogenic Potential of TWIST1 in Human Mammary Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Laurent Jacqueroud

    2016-05-01

    Full Text Available The TWIST1 embryonic transcription factor displays biphasic functions during the course of carcinogenesis. It facilitates the escape of cells from oncogene-induced fail-safe programs (senescence, apoptosis and their consequent neoplastic transformation. Additionally, it promotes the epithelial-to-mesenchymal transition and the initiation of the metastatic spread of cancer cells. Interestingly, cancer cells recurrently remain dependent on TWIST1 for their survival and/or proliferation, making TWIST1 their Achilles’ heel. TWIST1 has been reported to form either homodimeric or heterodimeric complexes mainly in association with the E bHLH class I proteins. These complexes display distinct, sometimes even antagonistic, functions during development and unequal prometastatic functions in prostate cancer cells. Using a tethered dimer strategy, we successively assessed the ability of TWIST1 dimers to cooperate with an activated version of RAS in human mammary epithelial cell transformation, to provide mice with the ability to spontaneously develop breast tumors, and lastly to maintain a senescence program at a latent state in several breast cancer cell lines. We demonstrate that the TWIST1-E12 complex, unlike the homodimer, is an oncogenic form of TWIST1 in mammary epithelial cells and that efficient binding of both partners is a prerequisite for its activity. The detection of the heterodimer in human premalignant lesions by a proximity ligation assay, at a stage preceding the initiation of the metastatic cascade, is coherent with such an oncogenic function. TWIST1-E protein heterodimeric complexes may thus constitute the main active forms of TWIST1 with regard to senescence inhibition over the time course of breast tumorigenesis.

  17. Structural basis of the heterodimerization of the MST and RASSF SARAH domains in the Hippo signalling pathway.

    Science.gov (United States)

    Hwang, Eunha; Cheong, Hae-Kap; Ul Mushtaq, Ameeq; Kim, Hye-Yeon; Yeo, Kwon Joo; Kim, Eunhee; Lee, Woo Cheol; Hwang, Kwang Yeon; Cheong, Chaejoon; Jeon, Young Ho

    2014-07-01

    Despite recent progress in research on the Hippo signalling pathway, the structural information available in this area is extremely limited. Intriguingly, the homodimeric and heterodimeric interactions of mammalian sterile 20-like (MST) kinases through the so-called `SARAH' (SAV/RASSF/HPO) domains play a critical role in cellular homeostasis, dictating the fate of the cell regarding cell proliferation or apoptosis. To understand the mechanism of the heterodimerization of SARAH domains, the three-dimensional structures of an MST1-RASSF5 SARAH heterodimer and an MST2 SARAH homodimer were determined by X-ray crystallography and were analysed together with that previously determined for the MST1 SARAH homodimer. While the structure of the MST2 homodimer resembled that of the MST1 homodimer, the MST1-RASSF5 heterodimer showed distinct structural features. Firstly, the six N-terminal residues (Asp432-Lys437), which correspond to the short N-terminal 3₁₀-helix h1 kinked from the h2 helix in the MST1 homodimer, were disordered. Furthermore, the MST1 SARAH domain in the MST1-RASSF5 complex showed a longer helical structure (Ser438-Lys480) than that in the MST1 homodimer (Val441-Lys480). Moreover, extensive polar and nonpolar contacts in the MST1-RASSF5 SARAH domain were identified which strengthen the interactions in the heterodimer in comparison to the interactions in the homodimer. Denaturation experiments performed using urea also indicated that the MST-RASSF heterodimers are substantially more stable than the MST homodimers. These findings provide structural insights into the role of the MST1-RASSF5 SARAH domain in apoptosis signalling.

  18. Negative Effects of Chronic Rapamycin Treatment on Behavior in a Mouse Model of Fragile X Syndrome

    Directory of Open Access Journals (Sweden)

    Rachel M. Saré

    2018-01-01

    Full Text Available Fragile X syndrome (FXS, the most common form of inherited intellectual disability, is also highly associated with autism spectrum disorders (ASD. It is caused by expansion of a CGG repeat sequence on the X chromosome resulting in silencing of the FMR1 gene. This is modeled in the mouse by deletion of Fmr1 (Fmr1 KO. Fmr1 KO mice recapitulate many of the behavioral features of the disorder including seizure susceptibility, hyperactivity, impaired social behavior, sleep problems, and learning and memory deficits. The mammalian target of rapamycin pathway (mTORC1 is upregulated in Fmr1 KO mice and is thought to be important for the pathogenesis of this disorder. We treated Fmr1 KO mice chronically with an mTORC1 inhibitor, rapamycin, to determine if rapamycin treatment could reverse behavioral phenotypes. We performed open field, zero maze, social behavior, sleep, passive avoidance, and audiogenic seizure testing. We found that pS6 was upregulated in Fmr1 KO mice and normalized by rapamycin treatment, but, except for an anxiogenic effect, it did not reverse any of the behavioral phenotypes examined. In fact, rapamycin treatment had an adverse effect on sleep and social behavior in both control and Fmr1 KO mice. These results suggest that targeting the mTOR pathway in FXS is not a good treatment strategy and that other pathways should be considered.

  19. Rapamycin-induced autophagy restricts porcine epidemic diarrhea virus infectivity in porcine intestinal epithelial cells.

    Science.gov (United States)

    Ko, Seongyeol; Gu, Min Jeong; Kim, Cheol Gyun; Kye, Yoon Chul; Lim, Younggap; Lee, Ji Eun; Park, Byung-Chul; Chu, Hyuk; Han, Seung Hyun; Yun, Cheol-Heui

    2017-10-01

    Porcine epidemic diarrhea virus (PEDV) invades porcine intestinal epithelial cells (IECs) and causes diarrhea and dehydration in pigs. In the present study, we showed a suppression of PEDV infection in porcine jejunum intestinal epithelial cells (IPEC-J2) by an increase in autophagy. Autophagy was activated by rapamycin at a dose that does not affect cell viability and tight junction permeability. The induction of autophagy was examined by LC3I/LC3II conversion. To confirm the autophagic-flux (entire autophagy pathway), autophagolysosomes were examined by an immunofluorescence assay. Pre-treatment with rapamycin significantly restricted not only a 1 h infection but also a longer infection (24 h) with PEDV, while this effect disappeared when autophagy was blocked. Co-localization of PEDV and autophagosomes suggests that PEDV could be a target of autophagy. Moreover, alleviation of PEDV-induced cell death in IPEC-J2 cells pretreated with rapamycin demonstrates a protective effect of rapamycin against PEDV-induced epithelial cell death. Collectively, the present study suggests an early prevention against PEDV infection in IPEC-J2 cells via autophagy that might be an effective strategy for the restriction of PEDV, and opens up the possibility of the use of rapamycin in vivo as an effective prophylactic and prevention treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. E-selectin targeted immunoliposomes for rapamycin delivery to activated endothelial cells.

    Science.gov (United States)

    Gholizadeh, Shima; Visweswaran, Ganesh Ram R; Storm, Gert; Hennink, Wim E; Kamps, Jan A A M; Kok, Robbert J

    2017-10-13

    Activated endothelial cells play a pivotal role in the pathology of inflammatory disorders and thus present a target for therapeutic intervention by drugs that intervene in inflammatory signaling cascades, such as rapamycin (mammalian target of rapamycin (mTOR) inhibitor). In this study we developed anti-E-selectin immunoliposomes for targeted delivery to E-selectin over-expressing tumor necrosis factor-α (TNF-α) activated endothelial cells. Liposomes composed of 1,2-dipalmitoyl-sn-glycero-3.;hosphocholine (DPPC), Cholesterol, and 1,2-Distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethyleneglycol)-2000]-maleimide (DSPE-PEG-Mal) were loaded with rapamycin via lipid film hydration, after which they were further functionalized by coupling N-succinimidyl-S-acetylthioacetate (SATA)-modified mouse anti human E-selectin antibodies to the distal ends of the maleimidyl (Mal)-PEG groups. In cell binding assays, these immunoliposomes bound specifically to TNF-α activated endothelial cells. Upon internalization, rapamycin loaded immunoliposomes inhibited proliferation and migration of endothelial cells, as well as expression of inflammatory mediators. Our findings demonstrate that rapamycin-loaded immunoliposomes can specifically inhibit inflammatory responses in inflamed endothelial cells. Copyright © 2017. Published by Elsevier B.V.

  1. Rapamycin increases oxidative stress response gene expression in adult stem cells

    Science.gov (United States)

    Kofman, Amber E.; McGraw, Margeaux R.; Payne, Christopher J.

    2012-01-01

    Balancing quiescence with proliferation is of paramount importance for adult stem cells in order to avoid hyperproliferation and cell depletion. In some models, stem cell exhaustion may be reversed with the drug rapamycin, which was shown can suppress cellular senescence in vitro and extend lifespan in animals. We hypothesized that rapamycin increases the expression of oxidative stress response genes in adult stem cells, and that these gene activities diminish with age. To test our hypothesis, we exposed mice to rapamycin and then examined the transcriptome of their spermatogonial stem cells (SSCs). Gene expression microarray analysis revealed that numerous oxidative stress response genes were upregulated upon rapamycin treatment, including superoxide dismutase 1, glutathione reductase, and delta-aminolevulinate dehydratase. When we examined the expression of these genes in 55-week-old wild type SSCs, their levels were significantly reduced compared to 3-week-old SSCs, suggesting that their downregulation is coincident with the aging process in adult stem cells. We conclude that rapamycin-induced stimulation of oxidative stress response genes may promote cellular longevity in SSCs, while a decline in gene expression in aged stem cells could reflect the SSCs' diminished potential to alleviate oxidative stress, a hallmark of aging. PMID:22529334

  2. Mammalian target of rapamycin complex 1 signalling is essential for germinal centre reaction.

    Science.gov (United States)

    Li, Bingshou; Li, Zhirong; Wang, Pengcheng; Huang, Qizhao; Xu, Lifan; He, Ran; Ye, Lilin; Bai, Qiang

    2017-10-01

    The mammalian target of rapamycin (mTOR) is a serine-threonine kinase that has been shown to be essential for the differentiation and function of various immune cells. Earlier in vitro studies showed that mTOR signalling regulates B-cell biology by supporting their activation and proliferation. However, how mTOR signalling temporally regulates in vivo germinal centre B (GCB) cell development and differentiation into short-lived plasma cells, long-lived plasma cells and memory cells is still not well understood. In this study, we used a combined conditional/inducible knock-out system to investigate the temporal regulation of mTOR complex 1 (mTORC1) in the GCB cell response to acute lymphocytic choriomeningitis virus infection by deleting Raptor, a main component of mTORC1, specifically in B cells in pre- and late GC phase. Early Raptor deficiency strongly inhibited GCB cell proliferation and differentiation and plasma cell differentiation. Nevertheless, late GC Raptor deficiency caused only decreases in the size of memory B cells and long-lived plasma cells through poor maintenance of GCB cells, but it did not change their differentiation. Collectively, our data revealed that mTORC1 signalling supports GCB cell responses at both early and late GC phases during viral infection but does not regulate GCB cell differentiation into memory B cells and plasma cells at the late GC stage. © 2017 John Wiley & Sons Ltd.

  3. Rapamycin nanoparticles localize in diseased lung vasculature and prevent pulmonary arterial hypertension.

    Science.gov (United States)

    Segura-Ibarra, Victor; Amione-Guerra, Javier; Cruz-Solbes, Ana S; Cara, Francisca E; Iruegas-Nunez, David A; Wu, Suhong; Youker, Keith A; Bhimaraj, Arvind; Torre-Amione, Guillermo; Ferrari, Mauro; Karmouty-Quintana, Harry; Guha, Ashrith; Blanco, Elvin

    2017-05-30

    Vascular remodeling resulting from pulmonary arterial hypertension (PAH) leads to endothelial fenestrations. This feature can be exploited by nanoparticles (NP), allowing them to extravasate from circulation and accumulate in remodeled pulmonary vessels. Hyperactivation of the mTOR pathway in PAH drives pulmonary arterial smooth muscle cell proliferation. We hypothesized that rapamycin (RAP)-loaded NPs, an mTOR inhibitor, would accumulate in diseased lungs, selectively targeting vascular mTOR and preventing PAH progression. RAP poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-PCL) NPs were fabricated. NP accumulation and efficacy were examined in a rat monocrotaline model of PAH. Following intravenous (IV) administration, NP accumulation in diseased lungs was verified via LC/MS analysis and confocal imaging. Pulmonary arteriole thickness, right ventricular systolic pressures, and ventricular remodeling were determined to assess the therapeutic potential of RAP NPs. Monocrotaline-exposed rats showed increased NP accumulation within lungs compared to healthy controls, with NPs present to a high extent within pulmonary perivascular regions. RAP, in both free and NP form, attenuated PAH development, with histological analysis revealing minimal changes in pulmonary arteriole thickness and no ventricular remodeling. Importantly, NP-treated rats showed reduced systemic side effects compared to free RAP. This study demonstrates the potential for nanoparticles to significantly impact PAH through site-specific delivery of therapeutics. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. H2O2 production rate in Lactobacillus johnsonii is modulated via the interplay of a heterodimeric flavin oxidoreductase with a soluble 28 Kd PAS domain containing protein.

    Directory of Open Access Journals (Sweden)

    Ricardo B Valladares

    2015-07-01

    Full Text Available Host and commensals crosstalk, mediated by reactive oxygen species (ROS, has triggered a growing scientific interest to understand the mechanisms governing such interaction. However, the majority of the scientific studies published do not evaluate the ROS production by commensals bacteria. In this context we recently showed that Lactobacillus johnsonii N6.2, a strain of probiotic value, modulates the activity of the critical enzymes 2,3-indoleamine dioxygenase via H2O2 production. L. johnsonii N6.2 by decreasing IDO activity, is able to modify the tryptophan/kynurenine ratio in the host blood with further systemic consequences. Understanding the mechanisms of H2O2 production is critical to predict the probiotic value of these strains and to optimize bacterial biomass production in industrial processes. We performed a transcriptome analysis to identify genes differentially expressed in L. johnsonii N6.2 cells collected from cultures grown under different aeration conditions. Herein we described the biochemical characteristics of a heterodimeric FMN reductase (FRedA/B whose in vitro activity is controlled by LjPAS protein with a typical Per-Arnst-Sim (PAS sensor domain. Interestingly, LjPAS is fused to the FMN reductase domains in other lactobacillaceae. In L. johnsonii, LjPAS is encoded by an independent gene which expression is repressed under anaerobic conditions (>3 fold. Purified LjPAS was able to slow down the FRedA/B initial activity rate when the holoenzyme precursors (FredA, FredB and FMN were mixed in vitro. Altogether the results obtained suggest that LjPAS module regulates the H2O2 production helping the cells to minimize oxidative stress in response to environmental conditions.

  5. H2O2 production rate in Lactobacillus johnsonii is modulated via the interplay of a heterodimeric flavin oxidoreductase with a soluble 28 Kd PAS domain containing protein.

    Science.gov (United States)

    Valladares, Ricardo B; Graves, Christina; Wright, Kaitlyn; Gardner, Christopher L; Lorca, Graciela L; Gonzalez, Claudio F

    2015-01-01

    Host and commensals crosstalk, mediated by reactive oxygen species (ROS), has triggered a growing scientific interest to understand the mechanisms governing such interaction. However, the majority of the scientific studies published do not evaluate the ROS production by commensals bacteria. In this context we recently showed that Lactobacillus johnsonii N6.2, a strain of probiotic value, modulates the activity of the critical enzymes 2,3-indoleamine dioxygenase via H2O2 production. L. johnsonii N6.2 by decreasing IDO activity, is able to modify the tryptophan/kynurenine ratio in the host blood with further systemic consequences. Understanding the mechanisms of H2O2 production is critical to predict the probiotic value of these strains and to optimize bacterial biomass production in industrial processes. We performed a transcriptome analysis to identify genes differentially expressed in L. johnsonii N6.2 cells collected from cultures grown under different aeration conditions. Herein we described the biochemical characteristics of a heterodimeric FMN reductase (FRedA/B) whose in vitro activity is controlled by LjPAS protein with a typical Per-Arnst-Sim (PAS) sensor domain. Interestingly, LjPAS is fused to the FMN reductase domains in other lactobacillaceae. In L. johnsonii, LjPAS is encoded by an independent gene which expression is repressed under anaerobic conditions (>3 fold). Purified LjPAS was able to slow down the FRedA/B initial activity rate when the holoenzyme precursors (FredA, FredB, and FMN) were mixed in vitro. Altogether the results obtained suggest that LjPAS module regulates the H2O2 production helping the cells to minimize oxidative stress in response to environmental conditions.

  6. Transcriptional Profiling of Rapamycin-Treated Fibroblasts From Hypertrophic and Keloid Scars

    Science.gov (United States)

    Wong, Victor W.; You, Fanglei; Januszyk, Michael; Gurtner, Geoffrey C.; Kuang, Anna A.

    2016-01-01

    Excess scar formation after cutaneous injury can result in hypertrophic scar (HTS) or keloid formation. Modern strategies to treat pathologic scarring represent nontargeted approaches that produce suboptimal results. Mammalian target of rapamycin (mTOR), a central mediator of inflammation, has been proposed as a novel target to block fibroproliferation. To examine its mechanism of action, we performed genomewide microarray on human fibroblasts (from normal skin, HTS, and keloid scars) treated with the mTOR inhibitor, rapamycin. Hypertrophic scar and keloid fibroblasts demonstrated overexpression of collagen I and III that was effectively abrogated with rapamycin. Blockade of mTOR specifically impaired fibroblast expression of the collagen biosynthesis genes PLOD, PCOLCE, and P4HA, targets significantly overexpressed in HTS and keloid scars. These data suggest that pathologic scarring can be abrogated via modulation of mTOR pathways in procollagen and collagen processing. PMID:24835866

  7. Mood-stabilizing effects of rapamycin and its analog temsirolimus: relevance to autophagy.

    Science.gov (United States)

    Kara, Nirit Z; Flaisher-Grinberg, Shlomit; Anderson, Grant W; Agam, Galila; Einat, Haim

    2017-08-02

    Accumulated data support a relationship between mood disorders and cellular plasticity and resilience, some suggesting relevance to autophagy. Our previous data show that pharmacological enhancement of autophagy results in antidepressant-like effects in mice. The current study was designed to further examine the effects of autophagy enhancement on mood by testing the effects of subchronic treatment with the mammalian target of rapamycin inhibitors and autophagy enhancers rapamycin and temsirolimus in a model for mania and in a model for antidepressant action, respectively. The results show that rapamycin reduced mania-like aggression and reward-seeking behaviors, with no effects on locomotion. Temsirolimus reduced depression-related immobility in the forced-swim test without effects on locomotion in the open field or on anxiety-related measures in the elevated plus maze. Taken together with our previous findings, these data support the notion that enhancing autophagy may have mood-stabilizing effects.

  8. Positively charged amphiphilic chitosan derivative for the transscleral delivery of rapamycin.

    Science.gov (United States)

    Elsaid, Naba; Jackson, Timothy L; Gunic, Mirza; Somavarapu, Satyanarayana

    2012-12-13

    We explored the potential of an amphiphilic chitosan derivative to facilitate the transscleral delivery of rapamycin, a potential multitherapeutic agent with poor water solubility. The amphiphilic chitosan derivative, O-octanoyl-chitosan-polyethylene glycol (OChiPEG) graft copolymer, was analyzed using Fourier-transform infrared spectroscopy (FT-IR). OChiPEG micelles were prepared via the thin film method and characterized for their size using dynamic light scattering (DLS), zeta potential using laser Doppler velocimetry (LDV), morphology using transmission electron microscopy (TEM), drug entrapment efficiency (EE), and drug loading (DL) efficiency using reversed-phase high performance liquid chromatography (RP-HPLC), critical micelle concentration (CMC) using spectrofluorometry, and thermal properties using differential scanning calorimetry (DSC) and x-ray powder diffraction (XRPD). Scleral permeation and retention of rapamycin from the drug-loaded micelles were determined in porcine sclera clamped in Ussing chambers, using RP-HPLC. Conjugation of hydrophilic and hydrophobic groups to chitosan was confirmed using FT-IR. Rapamycin-loaded micelles of particle size 40.6 nm and zeta potential + 6.84 mV were prepared successfully. These carriers exhibited a high EE and DL of 85.6 and 16.3%, respectively, and a CMC of 16.6 μM. OChiPEG micelles showed a high rapamycin scleral retention (14.8 ± 0.81 μg/g) with successful transscleral permeation (5.57 ± 1.04 × 10(-8) cm(2) · s(-1)). Positively charged OChiPEG micelles loaded with rapamycin were prepared successfully. These showed a high scleral retention and successful permeation of rapamycin, and therefore may be useful for the topical delivery of other hydrophobic agents.

  9. Rapamycin inhibits IGF-1 stimulated cell motility through PP2A pathway.

    Directory of Open Access Journals (Sweden)

    Lei Liu

    2010-05-01

    Full Text Available Serine/threonine (Ser/Thr protein phosphatase 2A (PP2A has been implicated as a novel component of the mammalian target of rapamycin (mTOR signaling pathway. Recently we have demonstrated that mTOR regulates cell motility in part through p70 S6 kinase 1 (S6K1 and eukaryotic initiation factor 4E (eIF4E binding protein 1 (4E-BP1 pathways. Little is known about the role of PP2A in the mTOR-mediated cell motility. Here we show that rapamycin inhibited the basal or insulin-like growth factor 1 (IGF-1-induced motility of human Ewing sarcoma (Rh1 and rhabdomyosarcoma (Rh30 cells. Treatment of the cells with rapamycin activated PP2A activity, and concurrently inhibited IGF-1 stimulated phosphorylation of Erk1/2. Inhibition of Erk1/2 with PD98059 did not significantly affect the basal mobility of the cells, but dramatically inhibited IGF-1-induced cell motility. Furthermore, inhibition of PP2A with okadaic acid significantly attenuated the inhibitory effect of rapamycin on IGF-1-stimulated phosphorylation of Erk1/2 as well as cell motility. Consistently, expression of dominant negative PP2A conferred resistance to IGF-1-stimulated phosphorylation of Erk1/2 and cell motility. Expression of constitutively active MKK1 also attenuated rapamycin inhibition of IGF-1-stimulated phosphorylation of Erk1/2 and cell motility. The results suggest that rapamycin inhibits cell motility, in part by targeting PP2A-Erk1/2 pathway.

  10. Rapamycin facilitates fracture healing through inducing cell autophagy and suppressing cell apoptosis in bone tissues.

    Science.gov (United States)

    Yin, Z-Y; Yin, J; Huo, Y-F; Yu, J; Sheng, L-X; Dong, Y-F

    2017-11-01

    To investigate the changes in cell autophagy and the molecular mechanism of rapamycin affecting the fracture healing. Sprague-Dawley (SD) rats were used to establish the right femoral shaft fracture models, and then underwent immunofluorescence assay to detect the autophagy level in bone tissues. After model establishment, SD rats were divided into two groups, the control group and the rapamycin group (1 mg/kg/d). Respectively, at the 2nd, 4th, and 6th week, rats were randomly selected from each group for X-ray and Micro-computed tomography (Micro-CT) examinations to determine callus growth, immunofluorescence assay to detect the protein expression of light chain 3 II (LC3 II), immunohistochemistry to evaluate the autophagy level through detecting the expression of Beclin1 in rats, Western blotting assay to detect cell apoptosis in tissues, hematoxylin and eosin staining (HE staining) to evaluate the osteoblastic activity through count of osteoblast in bone tissue at the end of fracture, and measure the expression of vascular endothelial growth factors (VEGF). Significant increases were seen in protein expression of cells in bone tissues at the end of fracture. In rapamycin group, callus formation and calcification level in rats were all higher than those in control group; compared with control group, for rats in rapamycin group, cell autophagy was significantly elevated in bone tissues, while cell apoptosis at the end of fracture was reduced with a significant increase in osteoblastic activity. The expression of VEGF in rapamycin group was higher than that in control group. Rapamycin can facilitate fracture healing through inducing cell apoptosis and suppressing cell apoptosis in bone tissues.

  11. The rapamycin-regulated gene expression signature determines prognosis for breast cancer

    Directory of Open Access Journals (Sweden)

    Tsavachidis Spiridon

    2009-09-01

    Full Text Available Abstract Background Mammalian target of rapamycin (mTOR is a serine/threonine kinase involved in multiple intracellular signaling pathways promoting tumor growth. mTOR is aberrantly activated in a significant portion of breast cancers and is a promising target for treatment. Rapamycin and its analogues are in clinical trials for breast cancer treatment. Patterns of gene expression (metagenes may also be used to simulate a biologic process or effects of a drug treatment. In this study, we tested the hypothesis that the gene-expression signature regulated by rapamycin could predict disease outcome for patients with breast cancer. Results Colony formation and sulforhodamine B (IC50 in vitro and in vivo gene expression data identified a signature, termed rapamycin metagene index (RMI, of 31 genes upregulated by rapamycin treatment in vitro as well as in vivo (false discovery rate of 10%. In the Miller dataset, RMI did not correlate with tumor size or lymph node status. High (>75th percentile RMI was significantly associated with longer survival (P = 0.015. On multivariate analysis, RMI (P = 0.029, tumor size (P = 0.015 and lymph node status (P = 0.001 were prognostic. In van 't Veer study, RMI was not associated with the time to develop distant metastasis (P = 0.41. In the Wang dataset, RMI predicted time to disease relapse (P = 0.009. Conclusion Rapamycin-regulated gene expression signature predicts clinical outcome in breast cancer. This supports the central role of mTOR signaling in breast cancer biology and provides further impetus to pursue mTOR-targeted therapies for breast cancer treatment.

  12. Nuclear PIM1 confers resistance to rapamycin-impaired endothelial proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Walpen, Thomas; Kalus, Ina [Research Unit, Division Internal Medicine, University Hospital Zuerich, 8091 Zuerich (Switzerland); Schwaller, Juerg [Department of Biomedicine, University of Basel, 4031 Basel (Switzerland); Peier, Martin A. [Research Unit, Division Internal Medicine, University Hospital Zuerich, 8091 Zuerich (Switzerland); Battegay, Edouard J. [Research Unit, Division Internal Medicine, University Hospital Zuerich, 8091 Zuerich (Switzerland); Zurich Center for Integrative Human Physiology (ZIHP), 8057 Zuerich (Switzerland); Humar, Rok, E-mail: Rok.Humar@usz.ch [Research Unit, Division Internal Medicine, University Hospital Zuerich, 8091 Zuerich (Switzerland); Zurich Center for Integrative Human Physiology (ZIHP), 8057 Zuerich (Switzerland)

    2012-12-07

    Highlights: Black-Right-Pointing-Pointer Pim1{sup -/-} endothelial cell proliferation displays increased sensitivity to rapamycin. Black-Right-Pointing-Pointer mTOR inhibition by rapamycin enhances PIM1 cytosolic and nuclear protein levels. Black-Right-Pointing-Pointer Truncation of Pim1 beyond serine 276 results in nuclear localization of the kinase. Black-Right-Pointing-Pointer Nuclear PIM1 increases endothelial proliferation independent of rapamycin. -- Abstract: The PIM serine/threonine kinases and the mTOR/AKT pathway integrate growth factor signaling and promote cell proliferation and survival. They both share phosphorylation targets and have overlapping functions, which can partially substitute for each other. In cancer cells PIM kinases have been reported to produce resistance to mTOR inhibition by rapamycin. Tumor growth depends highly on blood vessel infiltration into the malignant tissue and therefore on endothelial cell proliferation. We therefore investigated how the PIM1 kinase modulates growth inhibitory effects of rapamycin in mouse aortic endothelial cells (MAEC). We found that proliferation of MAEC lacking Pim1 was significantly more sensitive to rapamycin inhibition, compared to wildtype cells. Inhibition of mTOR and AKT in normal MAEC resulted in significantly elevated PIM1 protein levels in the cytosol and in the nucleus. We observed that truncation of the C-terminal part of Pim1 beyond Ser 276 resulted in almost exclusive nuclear localization of the protein. Re-expression of this Pim1 deletion mutant significantly increased the proliferation of Pim1{sup -/-} cells when compared to expression of the wildtype Pim1 cDNA. Finally, overexpression of the nuclear localization mutant and the wildtype Pim1 resulted in complete resistance to growth inhibition by rapamycin. Thus, mTOR inhibition-induced nuclear accumulation of PIM1 or expression of a nuclear C-terminal PIM1 truncation mutant is sufficient to increase endothelial cell proliferation

  13. Rapamycin Maintains the Chondrocytic Phenotype and Interferes with Inflammatory Cytokine Induced Processes

    Directory of Open Access Journals (Sweden)

    Andrea De Luna-Preitschopf

    2017-07-01

    Full Text Available Osteoarthritis (OA is hallmarked by a progressive degradation of articular cartilage. Besides risk factors including trauma, obesity or genetic predisposition, inflammation has a major impact on the development of this chronic disease. During the course of inflammation, cytokines such as tumor necrosis factor-alpha(TNF-α and interleukin (IL-1β are secreted by activated chondrocytes as well as synovial cells and stimulate the production of other inflammatory cytokines and matrix degrading enzymes. The mTORC1 inhibitor rapamycin is a clinical approved immunosuppressant and several studies also verified its chondroprotective effects in OA. However, the effect of blocking the mechanistic target of rapamycin complex (mTORC1 on the inflammatory status within OA is not well studied. Therefore, we aimed to investigate if inhibition of mTORC1 by rapamycin can preserve and sustain chondrocytes in an inflammatory environment. Patient-derived chondrocytes were cultured in media supplemented with or without the mTORC1 inhibitor rapamycin. To establish an inflammatory environment, either TNF-α or IL-1β was added to the media (=OA-model. The chondroprotective and anti-inflammatory effects of rapamycin were evaluated using sulfated glycosaminoglycan (sGAG release assay, Caspase 3/7 activity assay, lactate dehydrogenase (LDH assay and quantitative real time polymerase chain reaction (PCR. Blocking mTORC1 by rapamycin reduced the release and therefore degradation of sGAGs, which are components of the extracellular matrix secreted by chondrocytes. Furthermore, blocking mTORC1 in OA chondrocytes resulted in an enhanced expression of the main chondrogenic markers. Rapamycin was able to protect chondrocytes from cell death in an OA-model shown by reduced Caspase 3/7 activity and diminished LDH release. Furthermore, inhibition of mTORC1 preserved the chondrogenic phenotype of OA chondrocytes, but also reduced inflammatory processes within the OA-model. This study

  14. TORC1 signaling inhibition by rapamycin and caffeine affect lifespan, global gene expression, and cell proliferation of fission yeast

    Science.gov (United States)

    Rallis, Charalampos; Codlin, Sandra; Bähler, Jürg

    2013-01-01

    Target of rapamycin complex 1 (TORC1) is implicated in growth control and aging from yeast to humans. Fission yeast is emerging as a popular model organism to study TOR signaling, although rapamycin has been thought to not affect cell growth in this organism. Here, we analyzed the effects of rapamycin and caffeine, singly and combined, on multiple cellular processes in fission yeast. The two drugs led to diverse and specific phenotypes that depended on TORC1 inhibition, including prolonged chronological lifespan, inhibition of global translation, inhibition of cell growth and division, and reprograming of global gene expression mimicking nitrogen starvation. Rapamycin and caffeine differentially affected these various TORC1-dependent processes. Combined drug treatment augmented most phenotypes and effectively blocked cell growth. Rapamycin showed a much more subtle effect on global translation than did caffeine, while both drugs were effective in prolonging chronological lifespan. Rapamycin and caffeine did not affect the lifespan via the pH of the growth media. Rapamycin prolonged the lifespan of nongrowing cells only when applied during the growth phase but not when applied after cells had stopped proliferation. The doses of rapamycin and caffeine strongly correlated with growth inhibition and with lifespan extension. This comprehensive analysis will inform future studies into TORC1 function and cellular aging in fission yeast and beyond. PMID:23551936

  15. Synergistic antitumor activity of rapamycin and EF24 via increasing ROS for the treatment of gastric cancer

    Directory of Open Access Journals (Sweden)

    Weiqian Chen

    2016-12-01

    Full Text Available Mechanistic/mammalian target of rapamycin (mTOR has emerged as a new potential therapeutic target for gastric cancer. Rapamycin and rapamycin analogs are undergoing clinical trials and have produced clinical responses in a subgroup of cancer patients. However, monotherapy with rapamycin at safe dosage fails to induce cell apoptosis and tumor regression which has hampered its clinical application. This has led to the exploration of more effective combinatorial regimens to enhance the effectiveness of rapamycin. In our present study, we have investigated the combination of rapamycin and a reactive oxygen species (ROS inducer EF24 in gastric cancer. We show that rapamycin increases intracellular ROS levels and displays selective synergistic antitumor activity with EF24 in gastric cancer cells. This activity was mediated through the activation of c-Jun N terminal kinase and endoplasmic reticulum stress (ER pathways in cancer cells. We also show that inhibiting ROS accumulation reverses ER stress and prevents apoptosis induced by the combination of rapamycin and EF24. These mechanisms were confirmed using human gastric cancer xenografts in immunodeficient mice. Taken together, our work provides a novel therapeutic strategy for the treatment of gastric cancer. The work reveals that ROS generation could be an important target for the development of new combination therapies for cancer treatment.

  16. Cryo-EM structure of Saccharomyces cerevisiae target of rapamycin complex 2.

    Science.gov (United States)

    Karuppasamy, Manikandan; Kusmider, Beata; Oliveira, Taiana M; Gaubitz, Christl; Prouteau, Manoel; Loewith, Robbie; Schaffitzel, Christiane

    2017-11-23

    The target of rapamycin (TOR) kinase assembles into two distinct multiprotein complexes, conserved across eukaryote evolution. In contrast to TOR complex 1 (TORC1), TORC2 kinase activity is not inhibited by the macrolide rapamycin. Here, we present the structure of Saccharomyces cerevisiae TORC2 determined by electron cryo-microscopy. TORC2 contains six subunits assembling into a 1.4 MDa rhombohedron. Tor2 and Lst8 form the common core of both TOR complexes. Avo3/Rictor is unique to TORC2, but interacts with the same HEAT repeats of Tor2 that are engaged by Kog1/Raptor in mammalian TORC1, explaining the mutual exclusivity of these two proteins. Density, which we conclude is Avo3, occludes the FKBP12-rapamycin-binding site of Tor2's FRB domain rendering TORC2 rapamycin insensitive and recessing the kinase active site. Although mobile, Avo1/hSin1 further restricts access to the active site as its conserved-region-in-the-middle (CRIM) domain is positioned along an edge of the TORC2 active-site-cleft, consistent with a role for CRIM in substrate recruitment.

  17. GSK-3/Rb12 Pathway as a Novel Target of Rapamycin in Prostate Cancer

    Science.gov (United States)

    2005-11-01

    that also have a potent tumor suppressor effect. These drugs are currently being evaluated in clinical trials to treat human cancers including...tumors to inhibition of FRAP /mTOR." Proc Natl Acad Sci U S A 98(18): 10314-9. Noh, W. C., W. H. Mondesire, et al. (2004). "Determinants of rapamycin

  18. How longevity research can lead to therapies for Alzheimer's disease: The rapamycin story.

    Science.gov (United States)

    Richardson, Arlan; Galvan, Veronica; Lin, Ai-Ling; Oddo, Salvatore

    2015-08-01

    The discovery that rapamycin increases lifespan in mice and restores/delays many aging phenotypes has led to the speculation that rapamycin has 'anti-aging' properties. The major question discussed in this review is whether a manipulation that has anti-aging properties can alter the onset and/or progression of Alzheimer's disease, a disease in which age is the major risk factor. Rapamycin has been shown to prevent (and possibly restore in some cases) the deficit in memory observed in the mouse model of Alzheimer's disease (AD-Tg) as well as reduce Aβ and tau aggregation, restore cerebral blood flow and vascularization, and reduce microglia activation. All of these parameters are widely recognized as symptoms central to the development of AD. Furthermore, rapamycin has also been shown to improve memory and reduce anxiety and depression in several other mouse models that show cognitive deficits as well as in 'normal' mice. The current research shows the feasibility of using pharmacological agents that increase lifespan, such as those identified by the National Institute on Aging Intervention Testing Program, to treat Alzheimer's disease. Published by Elsevier Inc.

  19. New approach for local delivery of rapamycin by bioadhesive PLGA-carbopol nanoparticles.

    Science.gov (United States)

    Zou, Weiwei; Cao, Guangqing; Xi, Yanwei; Zhang, Na

    2009-01-01

    Local delivery of antiproliferative drugs encapsulated in biodegradable nanoparticles has shown promise as an experimental strategy for preventing vascular restenosis development. The general aim of this work was to develop polymeric nanoparticle carriers with bioadhesive properties, and to evaluate its adjuvant potential for local, intramural delivery of rapamycin for inhibition of restenosis. The bioadhesive rapamycin-loaded PLGA nanoparticles were obtained by applying carbopol 940 of different concentrations as stabilizer and bioadhesive agent. The resultant nanoparticles were characterized concerning physicochemical properties such as morphology, particle size, zeta potential, entrapment efficiency, drug loading, drug release in vitro, stability in vitro as well as the arterial uptake and retention ability in an ex-vivo model. The results revealed that carbopol could serve as a better stabilizer in the preparation of rapamycin-loaded PLGA nanoparticles compared with PVA, and the physicochemical characteristics of the obtained PLGA nanoparticles were affected by the concentration of carbopol. Furthermore, it was found that carbopol could impart the nanoparticles with bioadhesive properties, improving the rentention and uptake of nanoparticles in the arterial wall, benefiting the nanoparticles for efficient localization of therapeutic agents in restenosis site. Cell viability assay results showed that blank PLGA-carbopol nanoparticles exhibited low toxicity and excellent biocompatibility and rapamycin-loaded nanoparticles with a smaller particle size (carbopol stabilized bioadhesive nanoparticles against restenosis in vivo.

  20. Rapamycin prevents seizures after depletion of STRADA in a rare neurodevelopmental disorder.

    Science.gov (United States)

    Parker, Whitney E; Orlova, Ksenia A; Parker, William H; Birnbaum, Jacqueline F; Krymskaya, Vera P; Goncharov, Dmitry A; Baybis, Marianna; Helfferich, Jelte; Okochi, Kei; Strauss, Kevin A; Crino, Peter B

    2013-04-24

    A rare neurodevelopmental disorder in the Old Order Mennonite population called PMSE (polyhydramnios, megalencephaly, and symptomatic epilepsy syndrome; also called Pretzel syndrome) is characterized by infantile-onset epilepsy, neurocognitive delay, craniofacial dysmorphism, and histopathological evidence of heterotopic neurons in subcortical white matter and subependymal regions. PMSE is caused by a homozygous deletion of exons 9 to 13 of the LYK5/STRADA gene, which encodes the pseudokinase STRADA, an upstream inhibitor of mammalian target of rapamycin complex 1 (mTORC1). We show that disrupted pathfinding in migrating mouse neural progenitor cells in vitro caused by STRADA depletion is prevented by mTORC1 inhibition with rapamycin or inhibition of its downstream effector p70 S6 kinase (p70S6K) with the drug PF-4708671 (p70S6Ki). We demonstrate that rapamycin can rescue aberrant cortical lamination and heterotopia associated with STRADA depletion in the mouse cerebral cortex. Constitutive mTORC1 signaling and a migration defect observed in fibroblasts from patients with PMSE were also prevented by mTORC1 inhibition. On the basis of these preclinical findings, we treated five PMSE patients with sirolimus (rapamycin) without complication and observed a reduction in seizure frequency and an improvement in receptive language. Our findings demonstrate a mechanistic link between STRADA loss and mTORC1 hyperactivity in PMSE, and suggest that mTORC1 inhibition may be a potential treatment for PMSE as well as other mTOR-associated neurodevelopmental disorders.

  1. Rapamycin Conditioning of Dendritic Cells Differentiated from Human ES Cells Promotes a Tolerogenic Phenotype

    Directory of Open Access Journals (Sweden)

    Kathryn M. Silk

    2012-01-01

    Full Text Available While human embryonic stem cells (hESCs may one day facilitate the treatment of degenerative diseases requiring cell replacement therapy, the success of regenerative medicine is predicated on overcoming the rejection of replacement tissues. Given the role played by dendritic cells (DCs in the establishment of immunological tolerance, we have proposed that DC, rendered tolerogenic during their differentiation from hESC, might predispose recipients to accept replacement tissues. As a first step towards this goal, we demonstrate that DC differentiated from H1 hESCs (H1-DCs are particularly responsive to the immunosuppressive agent rapamycin compared to monocyte-derived DC (moDC. While rapamycin had only modest impact on the phenotype and function of moDC, H1-DC failed to upregulate CD40 upon maturation and displayed reduced immunostimulatory capacity. Furthermore, coculture of naïve allogeneic T cells with rapamycin-treated H1-DC promoted an increased appearance of CD25hi Foxp3+ regulatory T cells, compared to moDC. Our findings suggest that conditioning of hESC-derived DC with rapamycin favours a tolerogenic phenotype.

  2. Treating brain tumor-initiating cells using a combination of myxoma virus and rapamycin.

    Science.gov (United States)

    Zemp, Franz J; Lun, Xueqing; McKenzie, Brienne A; Zhou, Hongyuan; Maxwell, Lori; Sun, Beichen; Kelly, John J P; Stechishin, Owen; Luchman, Artee; Weiss, Samuel; Cairncross, J Gregory; Hamilton, Mark G; Rabinovich, Brian A; Rahman, Masmudur M; Mohamed, Mohamed R; Smallwood, Sherin; Senger, Donna L; Bell, John; McFadden, Grant; Forsyth, Peter A

    2013-07-01

    Intratumoral heterogeneity in glioblastoma multiforme (GBM) poses a significant barrier to therapy in certain subpopulation such as the tumor-initiating cell population, being shown to be refractory to conventional therapies. Oncolytic virotherapy has the potential to target multiple compartments within the tumor and thus circumvent some of the barriers facing conventional therapies. In this study, we investigate the oncolytic potential of myxoma virus (MYXV) alone and in combination with rapamycin in vitro and in vivo using human brain tumor-initiating cells (BTICs). We cultured fresh GBM specimens as neurospheres and assayed their growth characteristics in vivo. We then tested the susceptibility of BTICs to MYXV infection with or without rapamycin in vitro and assessed viral biodistribution/survival in vivo in orthotopic xenografts. The cultured neurospheres were found to retain stem cell markers in vivo, and they closely resembled human infiltrative GBM. In this study we determined that (i) all patient-derived BTICs tested, including those resistant to temozolomide, were susceptible to MYXV replication and killing in vitro; (ii) MYXV replicated within BTICs in vivo, and intratumoral administration of MYXV significantly prolonged survival of BTIC-bearing mice; (iii) combination therapy with MYXV and rapamycin improved antitumor activity, even in mice bearing "advanced" BTIC tumors; (iv) MYXV treatment decreased expression of stem cell markers in vitro and in vivo. Our study suggests that MYXV in combination with rapamycin infects and kills both the BTICs and the differentiated compartments of GBM and may be an effective treatment even in TMZ-resistant patients.

  3. Oncolytic virotherapy synergism with signaling inhibitors: Rapamycin increases myxoma virus tropism for human tumor cells.

    Science.gov (United States)

    Stanford, Marianne M; Barrett, John W; Nazarian, Steven H; Werden, Steven; McFadden, Grant

    2007-02-01

    Myxoma virus is a rabbit-specific poxvirus pathogen that also exhibits a unique tropism for human tumor cells and is dramatically oncolytic for human cancer xenografts. Most tumor cell lines tested are permissive for myxoma infection in a fashion intimately tied to the activation state of Akt kinase. A host range factor of myxoma virus, M-T5, directly interacts with Akt and mediates myxoma virus tumor cell tropism. mTOR is a regulator of cell growth and metabolism downstream of Akt and is specifically inhibited by rapamycin. We report that treatment of nonpermissive human tumor cell lines, which normally restrict myxoma virus replication, with rapamycin dramatically increased virus tropism and spread in vitro. This increased myxoma replication is concomitant with global effects on mTOR signaling, specifically, an increase in Akt kinase. In contrast to the effects on human cancer cells, rapamycin does not increase myxoma virus replication in rabbit cell lines or permissive human tumor cell lines with constitutively active Akt. This indicates that rapamycin increases the oncolytic capacity of myxoma virus for human cancer cells by reconfiguring the internal cell signaling environment to one that is optimal for productive virus replication and suggests the possibility of a potentially therapeutic synergism between kinase signaling inhibitors and oncolytic poxviruses for cancer treatment.

  4. Rapamycin potentiates cytotoxicity by docetaxel possibly through downregulation of Survivin in lung cancer cells

    Directory of Open Access Journals (Sweden)

    Li Hui

    2011-03-01

    Full Text Available Abstract Background To elucidate whether rapamycin, the inhibitor of mTOR (mammalian target of rapamycin, can potentiate the cytotoxic effect of docetaxel in lung cancer cells and to probe the mechanism underlying such enhancement. Methods Lung cancer cells were treated with docetaxel and rapamycin. The effect on the proliferation of lung cancer cells was evaluated using the MTT method, and cell apoptosis was measured by flow cytometry. Protein expression and level of phosphorylation were assayed using Western Blot method. Results Co-treatment of rapamycin and docetaxel was found to favorably enhance the cytotoxic effect of docetaxel in four lung cancer cell lines. This tumoricidal boost is associated with a reduction in the expression and phosphorylation levels of Survivin and ERK1/2, respectively. Conclusion The combined application of mTOR inhibitor and docetaxel led to a greater degree of cancer cell killing than that by either compound used alone. Therefore, this combination warrants further investigation in its suitability of serving as a novel therapeutic scheme for treating advanced and recurrent lung cancer patients.

  5. Rapamycin doses sufficient to extend lifespan do not compromise muscle mitochondrial content or endurance

    DEFF Research Database (Denmark)

    Widlund, Anne Lykkegaard; Vang, Ole; Ye, Lan

    2013-01-01

    and compromise the function of mitochondria in cultured muscle cells, implying that defects in bioenergetics might be an unavoidable consequence of targeting mTORC1 in vivo. Therefore, we tested whether rapamycin, at the same doses used to extend lifespan, affects mitochondrial function in skeletal muscle. While...

  6. Multi-scale optical imaging of the delayed type hypersensitivity reaction attenuated by rapamycin.

    Science.gov (United States)

    Luo, Meijie; Zhang, Zhihong; Li, Hui; Qiao, Sha; Liu, Zheng; Fu, Ling; Shen, Guanxin; Luo, Qingming

    2014-01-01

    Neutrophils and monocytes/macrophages (MMs) play important roles in the development of cell-mediated delayed type hypersensitivity (DTH). However, the dynamics of neutrophils and MMs during the DTH reaction and how the immunosuppressant rapamycin modulates their behavior in vivo are rarely reported. Here, we take advantage of multi-scale optical imaging techniques and a footpad DTH reaction model to non-invasively investigate the dynamic behavior and properties of immune cells from the whole field of the footpad to the cellular level. During the classic elicitation phase of the DTH reaction, both neutrophils and MMs obviously accumulated at inflammatory foci at 24 h post-challenge. Rapamycin treatment resulted in advanced neutrophil recruitment and vascular hyperpermeability at an early stage (4 h), the reduced accumulation of neutrophils (> 50% inhibition ratio) at 48 h, and the delayed involvement of MMs in inflammatory foci. The motility parameters of immune cells in the rapamycin-treated reaction at 4 h post-challenge displayed similar mean velocities, arrest durations, mean displacements, and confinements as the classic DTH reaction at 24 h. These results indicate that rapamycin treatment shortened the initial preparation stage of the DTH reaction and attenuated its intensity, which may be due to the involvement of T helper type 2 cells or regulatory T cells.

  7. Bad, a heterodimeric partner for Bcl-XL and Bcl-2, displaces Bax and promotes cell death.

    Science.gov (United States)

    Yang, E; Zha, J; Jockel, J; Boise, L H; Thompson, C B; Korsmeyer, S J

    1995-01-27

    To extend the mammalian cell death pathway, we screened for further Bcl-2 interacting proteins. Both yeast two-hybrid screening and lambda expression cloning identified a novel interacting protein, Bad, whose homology to Bcl-2 is limited to the BH1 and BH2 domains. Bad selectively dimerized with Bcl-xL as well as Bcl-2, but not with Bax, Bcl-xs, Mcl-1, A1, or itself. Bad binds more strongly to Bcl-xL than Bcl-2 in mammalian cells, and it reversed the death repressor activity of Bcl-xL, but not that of Bcl-2. When Bad dimerized with Bcl-xL, Bax was displaced and apoptosis was restored. When approximately half of Bax was heterodimerized, death was inhibited. The susceptibility of a cell to a death signal is determined by these competing dimerizations in which levels of Bad influence the effectiveness of Bcl-2 versus Bcl-xL in repressing death.

  8. Targeting EGFR/HER2 heterodimerization with a novel anti-HER2 domain II/III antibody.

    Science.gov (United States)

    Yu, Xiaojie; Wang, Lingfei; Shen, Yafeng; Wang, Chao; Zhang, Yajun; Meng, Yanchun; Yang, Yang; Liang, Beibei; Zhou, Bo; Wang, Huajing; Wei, Huafeng; Lei, Changhai; Hu, Shi; Li, Bohua

    2017-07-01

    HER2, a ligand-free tyrosine kinase receptor of the HER family, is frequently overexpressed in breast cancer. The anti-HER2 antibody trastuzumab has shown significant clinical benefits in metastatic breast cancer. Despite the effectiveness of trastuzumab, its efficacy remains variable and often modest. Thus, there is an urgent need to improve ErbB2-targeting therapy. Here, we describe a novel anti-HER2 antibody, 7C3, which was developed using hybridoma technique. Structural analysis confirms that the epitope of this antibody is in domain II/III of HER2. Moreover, a structural conformation change was observed in HER2 in complex with 7C3. Interestingly, this novel anti-HER2 antibody exhibits efficacy in blocking HER2/EGFR heterodimerization and signaling. The results highlight the different function role of HER2 domains and the unique potential of 7C3 to inhibit the HER2/EGFR heterodimer, which may complement current anti-HER2 treatments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Rapamycin reverses status epilepticus-induced memory deficits and dendritic damage.

    Directory of Open Access Journals (Sweden)

    Amy L Brewster

    Full Text Available Cognitive impairments are prominent sequelae of prolonged continuous seizures (status epilepticus; SE in humans and animal models. While often associated with dendritic injury, the underlying mechanisms remain elusive. The mammalian target of rapamycin complex 1 (mTORC1 pathway is hyperactivated following SE. This pathway modulates learning and memory and is associated with regulation of neuronal, dendritic, and glial properties. Thus, in the present study we tested the hypothesis that SE-induced mTORC1 hyperactivation is a candidate mechanism underlying cognitive deficits and dendritic pathology seen following SE. We examined the effects of rapamycin, an mTORC1 inhibitor, on the early hippocampal-dependent spatial learning and memory deficits associated with an episode of pilocarpine-induced SE. Rapamycin-treated SE rats performed significantly better than the vehicle-treated rats in two spatial memory tasks, the Morris water maze and the novel object recognition test. At the molecular level, we found that the SE-induced increase in mTORC1 signaling was localized in neurons and microglia. Rapamycin decreased the SE-induced mTOR activation and attenuated microgliosis which was mostly localized within the CA1 area. These findings paralleled a reversal of the SE-induced decreases in dendritic Map2 and ion channels levels as well as improved dendritic branching and spine density in area CA1 following rapamycin treatment. Taken together, these findings suggest that mTORC1 hyperactivity contributes to early hippocampal-dependent spatial learning and memory deficits and dendritic dysregulation associated with SE.

  10. BRAF gene alterations and enhanced mammalian target of rapamycin signaling in gangliogliomas.

    Science.gov (United States)

    Kakkar, Aanchal; Majumdar, Atreye; Pathak, Pankaj; Kumar, Anupam; Kumari, Kalpana; Tripathi, Manjari; Sharma, Mehar C; Suri, Vaishali; Tandon, Vivek; Chandra, Sarat P; Sarkar, Chitra

    2017-01-01

    Gangliogliomas (GGs) are slow-growing glioneuronal tumors seen in children and young adults. They are associated with intractable epilepsy, and have recently been found to harbor BRAF (B- rapidly accelerated fibrosarcoma) gene mutations. However, the mammalian target of rapamycin (mTOR) signaling pathway, downstream of BRAF, has not been evaluated extensively in GGs. GG cases were retrieved, clinical data obtained, and histopathological features reviewed. Sequencing for BRAF V600E mutation, analysis of BRAF copy number by quantitative real-time polymerase chain reaction, and immunohistochemistry for mTOR pathway markers p-S6 and p-4EBP1 were performed. Sixty-four cases of GG were identified (0.9% of central nervous system tumors). Of these, 28 had sufficient tumor tissue for further evaluation. Mixed glial and neuronal morphology was the commonest (64%) type. Focal cortical dysplasia was identified in the adjacent cortex (6 cases). BRAF V600E mutation was identified in 30% of GGs; BRAF copy number gain was observed in 50% of them. p-S6 and p-4EBP1 immunopositivity was seen in 57% cases each. Thus, mTOR pathway activation was seen in 81% cases, and was independent of BRAF alterations. 87% patients had Engel grade I outcome, while 13% had Engel grade II outcome. Both the Engel grade II cases analyzed showed BRAF V600E mutation. BRAF V600E mutation is frequent in GGs, as is BRAF gain; the former may serve as a target for personalized therapy in patients with residual tumors, necessitating its assessment in routine pathology reporting of these tumors. Evidence of mTOR pathway activation highlights similarities in the pathogenetic mechanisms underlying GG and focal cortical dysplasia, and suggests that mTOR inhibitors may be of utility in GG patients with persistent seizures after surgery.

  11. Mammalian Target of Rapamycin: Hitting the Bull's-Eye for Neurological Disorders

    Directory of Open Access Journals (Sweden)

    Zhao Zhong Chong

    2010-01-01

    Full Text Available The mammalian target of rapamycin (mTOR and its associated cell signaling pathways have garnered significant attention for their roles in cell biology and oncology. Interestingly,the explosion of information in this field has linked mTOR to neurological diseases with promising initial studies. mTOR, a 289 kDa serine/threonine protein kinase, plays an important role in cell growth and proliferation and is activated through phosphorylation in response to growth factors, mitogens and hormones. Growth factors, amino acids, cellular nutrients and oxygen deficiency can downregulate mTOR activity. The function of mTOR signaling is mediated primarily through two mTOR complexes: mTORC1 and mTORC2. mTORC1 initiates cap-dependent protein translation, a rate-limiting step of protein synthesis, through the phosphorylation of the targets eukaryotic initiation factor 4E-binding protein 1 (4EBP1 and p70 ribosomal S6 kinase (p70S6K. In contrast, mTORC2 regulates development of the cytoskeleton and also controls cell survival. Although closely tied to tumorigenesis, mTOR and the downstream signaling pathways are significantly involved in the central nervous system (CNS with synaptic plasticity, memory retention, neuroendocrine regulation associated with food intake and puberty and modulation of neuronal repair following injury. The signaling pathways of mTOR also are believed to be a significant component in a number of neurological diseases, such as Alzheimer disease, Parkinson disease and Huntington disease, tuberous sclerosis, neurofibromatosis, fragile X syndrome, epilepsy, traumatic brain injury and ischemic stroke. Here we describe the role of mTOR in the CNS and illustrate the potential for new strategies directed against neurological disorders.

  12. A cleavable signal peptide enhances cell surface delivery and heterodimerization of Cerulean-tagged angiotensin II AT1 and bradykinin B2 receptor

    Energy Technology Data Exchange (ETDEWEB)

    Quitterer, Ursula, E-mail: ursula.quitterer@pharma.ethz.ch [Molecular Pharmacology Unit, Swiss Federal Institute of Technology and University of Zurich, Zurich (Switzerland); Pohl, Armin; Langer, Andreas; Koller, Samuel; AbdAlla, Said [Molecular Pharmacology Unit, Swiss Federal Institute of Technology and University of Zurich, Zurich (Switzerland)

    2011-06-10

    Highlights: {yields} A new FRET-based method detects AT1/B2 receptor heterodimerization. {yields} First time application of AT1-Cerulean as a FRET donor. {yields} Method relies on signal peptide-enhanced cell surface delivery of AT1-Cerulean. {yields} A high FRET efficiency revealed efficient heterodimerization of AT1/B2R proteins. {yields} AT1/B2R heterodimers were functionally coupled to desensitization mechanisms. -- Abstract: Heterodimerization of the angiotensin II AT1 receptor with the receptor for the vasodepressor bradykinin, B2R, is known to sensitize the AT1-stimulated response of hypertensive individuals in vivo. To analyze features of that prototypic receptor heterodimer in vitro, we established a new method that uses fluorescence resonance energy transfer (FRET) and applies for the first time AT1-Cerulean as a FRET donor. The Cerulean variant of the green fluorescent protein as donor fluorophore was fused to the C-terminus of AT1, and the enhanced yellow fluorescent protein (EYFP) as acceptor fluorophore was fused to B2R. In contrast to AT1-EGFP, the AT1-Cerulean fusion protein was retained intracellularly. To facilitate cell surface delivery of AT1-Cerulean, a cleavable signal sequence was fused to the receptor's amino terminus. The plasma membrane-localized AT1-Cerulean resembled the native AT1 receptor regarding ligand binding and receptor activation. A high FRET efficiency of 24.7% between membrane-localized AT1-Cerulean and B2R-EYFP was observed with intact, non-stimulated cells. Confocal FRET microscopy further revealed that the AT1/B2 receptor heterodimer was functionally coupled to receptor desensitization mechanisms because activation of the AT1-Cerulean/B2R-EYFP heterodimer with a single agonist triggered the co-internalization of AT1/B2R. Receptor co-internalization was sensitive to inhibition of G protein-coupled receptor kinases, GRKs, as evidenced by a GRK-specific peptide inhibitor. In agreement with efficient AT1/B2R

  13. Antitumor activity of rapamycin in a Phase I trial for patients with recurrent PTEN-deficient glioblastoma.

    Directory of Open Access Journals (Sweden)

    Tim F Cloughesy

    2008-01-01

    Full Text Available There is much discussion in the cancer drug development community about how to incorporate molecular tools into early-stage clinical trials to assess target modulation, measure anti-tumor activity, and enrich the clinical trial population for patients who are more likely to benefit. Small, molecularly focused clinical studies offer the promise of the early definition of optimal biologic dose and patient population.Based on preclinical evidence that phosphatase and tensin homolog deleted on Chromosome 10 (PTEN loss sensitizes tumors to the inhibition of mammalian target of rapamycin (mTOR, we conducted a proof-of-concept Phase I neoadjuvant trial of rapamycin in patients with recurrent glioblastoma, whose tumors lacked expression of the tumor suppressor PTEN. We aimed to assess the safety profile of daily rapamycin in patients with glioma, define the dose of rapamycin required for mTOR inhibition in tumor tissue, and evaluate the antiproliferative activity of rapamycin in PTEN-deficient glioblastoma. Although intratumoral rapamycin concentrations that were sufficient to inhibit mTOR in vitro were achieved in all patients, the magnitude of mTOR inhibition in tumor cells (measured by reduced ribosomal S6 protein phosphorylation varied substantially. Tumor cell proliferation (measured by Ki-67 staining was dramatically reduced in seven of 14 patients after 1 wk of rapamycin treatment and was associated with the magnitude of mTOR inhibition (p = 0.0047, Fisher exact test but not the intratumoral rapamycin concentration. Tumor cells harvested from the Ki-67 nonresponders retained sensitivity to rapamycin ex vivo, indicating that clinical resistance to biochemical mTOR inhibition was not cell-intrinsic. Rapamycin treatment led to Akt activation in seven patients, presumably due to loss of negative feedback, and this activation was associated with shorter time-to-progression during post-surgical maintenance rapamycin therapy (p < 0.05, Logrank test.Rapamycin

  14. Inhibiting the Mammalian target of rapamycin blocks the development of experimental cerebral malaria.

    Science.gov (United States)

    Gordon, Emile B; Hart, Geoffrey T; Tran, Tuan M; Waisberg, Michael; Akkaya, Munir; Skinner, Jeff; Zinöcker, Severin; Pena, Mirna; Yazew, Takele; Qi, Chen-Feng; Miller, Louis H; Pierce, Susan K

    2015-06-02

    Malaria is an infectious disease caused by parasites of several Plasmodium spp. Cerebral malaria (CM) is a common form of severe malaria resulting in nearly 700,000 deaths each year in Africa alone. At present, there is no adjunctive therapy for CM. Although the mechanisms underlying the pathogenesis of CM are incompletely understood, it is likely that both intrinsic features of the parasite and the human host's immune response contribute to disease. The kinase mammalian target of rapamycin (mTOR) is a central regulator of immune responses, and drugs that inhibit the mTOR pathway have been shown to be antiparasitic. In a mouse model of CM, experimental CM (ECM), we show that the mTOR inhibitor rapamycin protects against ECM when administered within the first 4 days of infection. Treatment with rapamycin increased survival, blocked breakdown of the blood-brain barrier and brain hemorrhaging, decreased the influx of both CD4(+) and CD8(+) T cells into the brain and the accumulation of parasitized red blood cells in the brain. Rapamycin induced marked transcriptional changes in the brains of infected mice, and analysis of transcription profiles predicted that rapamycin blocked leukocyte trafficking to and proliferation in the brain. Remarkably, animals were protected against ECM even though rapamycin treatment significantly increased the inflammatory response induced by infection in both the brain and spleen. These results open a new avenue for the development of highly selective adjunctive therapies for CM by targeting pathways that regulate host and parasite metabolism. Malaria is a highly prevalent infectious disease caused by parasites of several Plasmodium spp. Malaria is usually uncomplicated and resolves with time; however, in about 1% of cases, almost exclusively among young children, malaria becomes severe and life threatening, resulting in nearly 700,000 deaths each year in Africa alone. Among the most severe complications of Plasmodium falciparum infection

  15. Identification and characterization of the regions involved in the nuclear translocation of the heterodimeric leishmanial DNA topoisomerase IB.

    Directory of Open Access Journals (Sweden)

    Christopher F Prada

    Full Text Available Leishmania donovani, the causative organism for visceral leishmaniasis, contains a unique heterodimeric DNA-topoisomerase IB (LdTopIB. LdTopIB is a heterodimer made up of a large subunit and a small subunit that must interact with each other to build an active enzyme able to solve the topological tensions on the DNA. As LdTopIB is located within the nucleus, one or more nuclear localization signals (NLS should exist to ensure its nuclear translocation. In this report three novel NLS have been identified through a sequential deletion study of the genes encoding of both subunits fused to that encoding the green fluorescent protein (GFP. NLS1 is a highly basic sequence of 43 amino acids in the C-terminal extension of the large protomer. We found two well-defined sequences in the small protomer: NLS2 is a 10-amino acid motif located in the N-terminal extension of the protein; NLS3 consists of a complex region of 28 amino acids placed in the vicinity of the catalytic Tyr-222 included at the conserved SKINY signature within the C-terminal. Furthermore, by means of yeast cell viability assays, conducted with several LdTopIB chimeras lacking any of the NLS motives, we have revealed that both subunits are transported independently to the nucleus. There was no evidence of LdTopIB accumulation in mitochondria or association to the kinetoplast DNA network. The results rule out the former hypothesis, which attributes nucleocytoplasmic transport of LdTopIB entirely to the large subunit. The LdTopIB is localized to the nucleus only.

  16. Heterodimerization of the Entamoeba histolytica EhCPADH virulence complex through molecular dynamics and protein-protein docking.

    Science.gov (United States)

    Montaño, Sarita; Orozco, Esther; Correa-Basurto, José; Bello, Martiniano; Chávez-Munguía, Bibiana; Betanzos, Abigail

    2017-02-01

    EhCPADH is a protein complex involved in the virulence of Entamoeba histolytica, the protozoan responsible for human amebiasis. It is formed by the EhCP112 cysteine protease and the EhADH adhesin. To explore the molecular basis of the complex formation, three-dimensional models were built for both proteins and molecular dynamics simulations (MDS) and docking calculations were performed. Results predicted that the pEhCP112 proenzyme and the mEhCP112 mature enzyme were globular and peripheral membrane proteins. Interestingly, in pEhCP112, the propeptide appeared hiding the catalytic site (C167, H329, N348); while in mEhCP112, this site was exposed and its residues were found structurally closer than in pEhCP112. EhADH emerged as an extended peripheral membrane protein with high fluctuation in Bro1 and V shape domains. 500 ns-long MDS and protein-protein docking predictions evidenced different heterodimeric complexes with the lowest free energy. pEhCP112 interacted with EhADH by the propeptide and C-terminal regions and mEhCP112 by the C-terminal through hydrogen bonds. In contrast, EhADH bound to mEhCP112 by 442-479 residues, adjacent to the target cell-adherence region (480-600 residues), and by the Bro1 domain (9-349 residues). Calculations of the effective binding free energy and per residue free energy decomposition showed that EhADH binds to mEhCP112 with a higher binding energy than to pEhCP112, mainly through van der Waals interactions and the nonpolar part of solvation energy. The EhADH and EhCP112 structural relationship was validated in trophozoites by immunofluorescence, TEM, and immunoprecipitation assays. Experimental findings fair agreed with in silico results.

  17. Synthesis and pharmacological characterization of dibenzodiazepinone-type heterodimeric and fluorescently labeled muscarinic receptor ligands

    OpenAIRE

    Xueke, She

    2017-01-01

    In humans, the family of muscarinic acetylcholine receptors (mAChR, MRs) comprises five subtypes (M1R-M5R), which are members of the class A GPCR superfamily and mediate the action of the neurotransmitter acetylcholine in the central and peripheral nervous system. For instance, the M2R, which binds to Gi/o heterotrimeric G-proteins, acts as a presynaptic autoreceptor in the brain and in the periphery. Accordingly, selective M2R antagonism in the CNS, resulting in enhanced cholinergic transmis...

  18. Evidence for Heterodimerization and Functional Interaction of the Angiotensin Type 2 Receptor and the Receptor MAS

    DEFF Research Database (Denmark)

    Leonhardt, Julia; Villela, Daniel C.; Teichmann, Anke

    2017-01-01

    The angiotensin type 2 receptor (AT2R) and the receptor MAS are receptors of the protective arm of the renin-angiotensin system. They mediate strikingly similar actions. Moreover, in various studies, AT2R antagonists blocked the effects of MAS agonists and vice versa. Such cross-inhibition may......, subfamily C-member 6. Dimerization of the AT2R was abolished when it was mutated at cysteine residue 35. AT2R and MAS stimulation with the respective agonists, Compound 21 or angiotensin-(1-7), significantly induced CX3C chemokine receptor-1 messenger RNA expression. Effects of each agonist were blocked...

  19. Taking Two to Tango: A Role for Ghrelin Receptor Heterodimerization in Stress and Reward

    Directory of Open Access Journals (Sweden)

    Harriet eSchellekens

    2013-08-01

    Full Text Available The gut hormone, ghrelin, is the only known peripherally derived orexigenic signal. It activates its centrally expressed receptor, the growth hormone secretagogue receptor (GHS-R1a, to stimulate food intake. The ghrelin signalling system has recently been suggested to play a key role at the interface of homeostatic control of appetite and the hedonic aspects of food intake, as a critical role for ghrelin in dopaminergic mesolimbic circuits involved in reward signalling has emerged. Moreover, enhanced plasma ghrelin levels are associated with conditions of physiological stress, which may underline the drive to eat calorie-dense ‘comfort-foods’ and signifies a role for ghrelin in stress-induced food reward behaviours. These complex and diverse functionalities of the ghrelinergic system are not yet fully elucidated and likely involve crosstalk with additional signalling systems. Interestingly, accumulating data over the last few years has shown the GHS-R1a receptor to dimerize with several additional G-protein coupled receptors (GPCRs involved in appetite signalling and reward, including the GHS-R1b receptor, the melanocortin 3 receptor (MC3, dopamine receptors (D1 and D2, and more recently, the serotonin 2C receptor (5-HT2C. GHS-R1a dimerization was shown to affect downstream signalling and receptor trafficking suggesting a potential novel mechanism for fine-tuning GHS-R1a receptor mediated activity. This review summarizes ghrelin’s role in food reward and stress and outlines the GHS-R1a dimer pairs identified to date. In addition, the downstream signalling and potential functional consequences of dimerization of the GHS-R1a receptor in appetite and stress-induced food reward behaviour are discussed. The existence of multiple GHS-R1a heterodimers has important consequences for future pharmacotherapies as it significantly increases the pharmacological diversity of the GHS-R1a receptor and has the potential to enhance specificity of novel

  20. Rapamycin enhances docetaxel-induced cytotoxicity in a androgen-independent prostate cancer xenograft model by survivin downregulation

    Energy Technology Data Exchange (ETDEWEB)

    Morikawa, Yasuyuki, E-mail: yasu-m@med.gunma-u.ac.jp [Department of Urology, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maeabshi, Gunma 3718511 (Japan); Koike, Hidekazu; Sekine, Yoshitaka; Matsui, Hiroshi; Shibata, Yasuhiro; Ito, Kazuto; Suzuki, Kazuhiro [Department of Urology, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maeabshi, Gunma 3718511 (Japan)

    2012-03-16

    Highlights: Black-Right-Pointing-Pointer Rapamycin (RPM) enhances the susceptibility of PC3 cells to docetaxel. Black-Right-Pointing-Pointer Low-dosage of docetaxel (DTX) did not reduce survivin expression levels in PC3 cells. Black-Right-Pointing-Pointer Combination treatment of RPM with DTX suppressed the expression of surviving. Black-Right-Pointing-Pointer SiRNA against survivin enhanced the susceptibility of PC3 cells to DTX. Black-Right-Pointing-Pointer RPM and DTX cotreatment inhibited PC3 cell growth and decreased surviving in vivo. -- Abstract: Background: Docetaxel is a first-line treatment choice in castration-resistant prostate cancer (CRPC). However, the management of CRPC remains an important challenge in oncology. There have been many reports on the effects of rapamycin, which is an inhibitor of the mammalian target of rapamycin (mTOR), in the treatment of carcinogenesis. We assessed the cytotoxic effects of the combination treatment of docetaxel and rapamycin in prostate cancer cells. Furthermore, we examined the relationship between these treatments and survivin, which is a member of the inhibitory apoptosis family. Methods: Prostate cancer cells were cultured and treated with docetaxel and rapamycin. The effects on proliferation were evaluated with the MTS assay. In addition, we evaluated the effect on proliferation of the combination treatment induced knockdown of survivin expression by small interfering RNA transfection and docetaxel. Protein expression levels were assayed using western blotting. PC3 cells and xenograft growth in nude mice were used to evaluate the in vivo efficacy of docetaxel and its combination with rapamycin. Results: In vitro and in vivo, the combination of rapamycin with docetaxel resulted in a greater inhibition of proliferation than treatment with rapamycin or docetaxel alone. In addition, in vitro and in vivo, rapamycin decreased basal surviving levels, and cotreatment with docetaxel further decreased these levels

  1. Beneficial effects of rapamycin in a Drosophila model for hereditary spastic paraplegia.

    Science.gov (United States)

    Xu, Shiyu; Stern, Michael; McNew, James A

    2017-01-15

    The locomotor deficits in the group of diseases referred to as hereditary spastic paraplegia (HSP) reflect degeneration of upper motor neurons, but the mechanisms underlying this neurodegeneration are unknown. We established a Drosophila model for HSP, atlastin (atl), which encodes an ER fusion protein. Here, we show that neuronal atl loss causes degeneration of specific thoracic muscles that is preceded by other pathologies, including accumulation of aggregates containing polyubiquitin, increased generation of reactive oxygen species and activation of the JNK-Foxo stress response pathway. We show that inhibiting the Tor kinase, either genetically or by administering rapamycin, at least partially reversed many of these pathologies. atl loss from muscle also triggered muscle degeneration and rapamycin-sensitive locomotor deficits, as well as polyubiquitin aggregate accumulation. These results indicate that atl loss triggers muscle degeneration both cell autonomously and nonautonomously. © 2017. Published by The Company of Biologists Ltd.

  2. A brain proteomic investigation of rapamycin effects in the Tsc1+/- mouse model.

    Science.gov (United States)

    Wesseling, Hendrik; Elgersma, Ype; Bahn, Sabine

    2017-01-01

    Tuberous sclerosis complex (TSC) is a rare monogenic disorder characterized by benign tumors in multiple organs as well as a high prevalence of epilepsy, intellectual disability and autism. TSC is caused by inactivating mutations in the TSC1 or TSC2 genes. Heterozygocity induces hyperactivation of mTOR which can be inhibited by mTOR inhibitors, such as rapamycin, which have proven efficacy in the treatment of TSC-associated symptoms. The aim of the present study was (1) to identify molecular changes associated with social and cognitive deficits in the brain tissue of Tsc1+/- mice and (2) to investigate the molecular effects of rapamycin treatment, which has been shown to ameliorate genotype-related behavioural deficits. Molecular alterations in the frontal cortex and hippocampus of Tsc1+/- and control mice, with or without rapamycin treatment, were investigated. A quantitative mass spectrometry-based shotgun proteomic approach (LC-MSE) was employed as an unbiased method to detect changes in protein levels. Changes identified in the initial profiling stage were validated using selected reaction monitoring (SRM). Protein Set Enrichment Analysis was employed to identify dysregulated pathways. LC-MSE analysis of Tsc1+/- mice and controls (n = 30) identified 51 proteins changed in frontal cortex and 108 in the hippocampus. Bioinformatic analysis combined with targeted proteomic validation revealed several dysregulated molecular pathways. Using targeted assays, proteomic alterations in the hippocampus validated the pathways "myelination", "dendrite," and "oxidative stress", an upregulation of ribosomal proteins and the mTOR kinase. LC-MSE analysis was also employed on Tsc1+/- and wildtype mice (n = 34) treated with rapamycin or vehicle. Rapamycin treatment exerted a stronger proteomic effect in Tsc1+/- mice with significant changes (mainly decreased expression) in 231 and 106 proteins, respectively. The cellular pathways "oxidative stress" and "apoptosis" were found

  3. PTEN and rapamycin inhibiting the growth of K562 cells through regulating mTOR signaling pathway

    Directory of Open Access Journals (Sweden)

    Chen Hao

    2008-12-01

    Full Text Available Abstract Objective To investigate, in vitro, the regulatory effects of tumor-suppressing gene PTEN on mTOR (mammalian target of rapamycin signaling pathway, the effects of transfected PTEN and rapamycin on the growth inhibition, and apoptosis induction for human leukemia cell line K562 cells. Methods K562 cells were transfected with recombined adenovirus-PTEN vector containing green fluorescent protein (Ad-PTEN-GFP, followed by the treatment of the cells with or without rapamycin. The proliferation inhibition rate and apoptotic rate of these transfected and/or rapamycin treated K562 cells were measured by MTT assay and flow cytometry (FCM, the expression levels of PTEN-, mTOR-, cyclinD1- and P27kip1- mRNA were measured by real-time fluorescent relative-quantification reverse transcriptional PCR (FQ-PCR, the protein expression levels of PTEN, Akt, p-Akt were detected by western blotting. Results The proliferation of K562 cells was inhibited by PTEN gene transfection with/without the treatment of rapamycin. The expression levels of PTEN- and P27kip1- mRNA were up-regulated, and the mTOR- and cyclinD1- mRNA were down-regulated in K562 cells after the cells transfected with wild type PTEN gene and treated with rapamycin. Conclusion PTEN and rapamycin inhibited mTOR expression by acting as an upstream regulator of mTOR. Low dose rapamycin in combination with over-expressed PTEN might have synergistic effects on inhibiting the proliferation and promoting apoptosis of K562 cells.

  4. ATP-Competitive Inhibitors of the Mammalian Target of Rapamycin: Design and Synthesis of Highly Potent and Selective Pyrazolopyrimidines

    Energy Technology Data Exchange (ETDEWEB)

    Zask, Arie; Verheijen, Jeroen C.; Curran, Kevin; Kaplan, Joshua; Richard, David J.; Nowak, Pawel; Malwitz, David J.; Brooijmans, Natasja; Bard, Joel; Svenson, Kristine; Lucas, Judy; Toral-Barza, Lourdes; Zhang, Wei-Guo; Hollander, Irwin; Gibbons, James J.; Abraham, Robert T.; Ayral-Kaloustian, Semiramis; Mansour, Tarek S.; Yu, Ker; (Wyeth)

    2009-09-18

    The mammalian target of rapamycin (mTOR), a central regulator of growth, survival, and metabolism, is a validated target for cancer therapy. Rapamycin and its analogues, allosteric inhibitors of mTOR, only partially inhibit one mTOR protein complex. ATP-competitive, global inhibitors of mTOR that have the potential for enhanced anticancer efficacy are described. Structural features leading to potency and selectivity were identified and refined leading to compounds with in vivo efficacy in tumor xenograft models.

  5. Effects of rapamycin treatment after controlled cortical impact injury on neurogenesis and synaptic reorganization in the mouse dentate gyrus

    Directory of Open Access Journals (Sweden)

    Corwin R Butler

    2015-11-01

    Full Text Available Post-traumatic epilepsy (PTE is one consequence of traumatic brain injury (TBI. A prominent cell signaling pathway activated in animal models of both TBI and epilepsy is the mammalian target of rapamycin (mTOR. Inhibition of mTOR with rapamycin has shown promise as a potential modulator of epileptogenesis in several animal models of epilepsy, but cellular mechanisms linking mTOR expression and epileptogenesis are unclear. In this study, the role of mTOR in modifying functional hippocampal circuit reorganization after focal TBI induced by controlled cortical impact was investigated. Rapamycin (3 or 10 mg/kg, an inhibitor of mTOR signaling, was administered by intraperitoneal injection beginning on the day of injury and continued daily until tissue collection. Relative to controls, rapamycin treatment reduced dentate granule cell area in the hemisphere ipsilateral to the injury two weeks post-injury. Brain injury resulted in a significant increase in doublecortin immunolabeling in the dentate gyrus ipsilateral to the injury, indicating increased neurogenesis shortly after TBI. Rapamycin treatment prevented the increase in doublecortin labeling, with no overall effect on Fluoro-Jade B staining in the ipsilateral hemisphere, suggesting that rapamycin treatment reduced posttraumatic neurogenesis but did not prevent cell loss after injury. At later times post-injury (8-13 weeks, evidence of mossy fiber sprouting and increased recurrent excitation of dentate granule cells was detected, which were attenuated by rapamycin treatment. Rapamycin treatment also diminished seizure prevalence relative to vehicle-treated controls after TBI. Collectively, these results support a role for adult neurogenesis in PTE development and suggest that suppression of epileptogenesis by mTOR inhibition includes effects on post-injury neurogenesis.

  6. Campylobacter jejuni induces colitis through activation of mammalian target of rapamycin signaling.

    Science.gov (United States)

    Sun, Xiaolun; Threadgill, Deborah; Jobin, Christian

    2012-01-01

    Campylobacter jejuni is the worldwide leading cause of bacterial-induced enteritis. The molecular and cellular events that lead to campylobacteriosis are poorly understood. We identify mammalian target of rapamycin (mTOR) as a signaling pathway that leads to C jejuni-induced intestinal inflammation. Germ-free (control) or conventionally derived Il10(-/-) mice that express enhanced green fluorescent protein (EGFP) under the control of nuclear factor κB (Il10(-/-); NF-κB(EGFP) mice) were infected with C jejuni (10(9) colony-forming units/mouse) for 12 days; their responses were determined using histologic, semiquantitative reverse-transcription polymerase chain reaction, fluorescence in situ hybridization, transmission electron microscopy, and tissue culture analyses. mTOR signaling was blocked by daily intraperitoneal injections of the pharmacologic inhibitor rapamycin (1.5 mg/kg). CD4(+) T cells were depleted by intraperitoneal injections of antibodies against CD4 (0.5 mg/mouse every 3 days). Bacterial survival in splenocytes was measured using a gentamycin killing assay. C jejuni induced intestinal inflammation, which correlated with activation of mTOR signaling and neutrophil infiltration. The inflamed intestines of these mice had increased levels of interleukin-1β, Cxcl2, interleukin-17a, and EGFP; C jejuni localized to colons and extraintestinal tissues of infected Il10(-/-); NF-κB(EGFP) mice compared with controls. Rapamycin, administered before or after introduction of C jejuni, blocked C jejuni-induced intestinal inflammation and bacterial accumulation. LC3II processing and killing of C jejuni were increased in splenocytes incubated with rapamycin compared with controls. mTOR signaling mediates C jejuni-induced colitis in Il10(-/-) mice, independently of T-cell activation. Factors involved in mTOR signaling might be therapeutic targets for campylobacteriosis. Copyright © 2012 AGA Institute. Published by Elsevier Inc. All rights reserved.

  7. Rapamycin inhibits the growth and muscle-sparing effects of clenbuterol.

    Science.gov (United States)

    Kline, William O; Panaro, Frank J; Yang, Hayung; Bodine, Sue C

    2007-02-01

    Clenbuterol and other beta2-adrenergic agonists are effective at inducing muscle growth and attenuating muscle atrophy through unknown mechanisms. This study tested the hypothesis that clenbuterol-induced growth and muscle sparing is mediated through the activation of Akt and mammalian target of rapamycin (mTOR) signaling pathways. Clenbuterol was administered to normal weight-bearing adult rats to examine the growth-inducing effects and to adult rats undergoing muscle atrophy as the result of hindlimb suspension or denervation to examine the muscle-sparing effects. The pharmacological inhibitor rapamycin was administered in combination with clenbuterol in vivo to determine whether activation of mTOR was involved in mediating the effects of clenbuterol. Clenbuterol administration increased the phosphorylation status of PKB/Akt, S6 kinase 1/p70(s6k), and eukaryotic initiation factor 4E binding protein 1/PHAS-1. Clenbuterol treatment induced growth by 27-41% in normal rats and attenuated muscle loss during hindlimb suspension by 10-20%. Rapamycin treatment resulted in a 37-97% suppression of clenbuterol-induced growth and a 100% reduction of the muscle-sparing effect. In contrast, rapamycin was unable to block the muscle-sparing effects of clenbuterol after denervation. Clenbuterol was also shown to suppress the expression of the MuRF1 and MAFbx transcripts in muscles from normal, denervated, and hindlimb-suspended rats. These results demonstrate that the effects of clenbuterol are mediated, in part, through the activation of Akt and mTOR signaling pathways.

  8. Balloon Coating with Rapamycin Using an On-site Coating Device

    Energy Technology Data Exchange (ETDEWEB)

    Schmehl, Joerg, E-mail: joerg.schmehl@med.uni-tuebingen.de [Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen (Germany); Ruhr, Juergen von der [Institute of Anatomy, University of Tuebingen (Germany); Dobratz, Markus; Kehlbach, Rainer [Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen (Germany); Braun, Isabelle [Translumina GmbH (Germany); Greiner, Tim-Oliver [Clinic of Thoracic and Cardiovascular Surgery, University Hospital of Tuebingen (Germany); Claussen, Claus D. [Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen (Germany); Behnisch, Boris [Translumina GmbH (Germany)

    2013-06-15

    Purpose. The efficacy of drug-eluting balloons has been demonstrated in clinical trials. The drug predominantly used is paclitaxel because of its lipophilic properties and the rapid onset of action. The aim of the investigation was to evaluate the feasibility and efficacy of an alternative balloon coating with rapamycin that can be applied on site.MethodsThe balloon coating (3.0/18 and 3.0/12 mm, Cathy No. 4, Translumina GmbH) with rapamycin was conducted with a coating machine (Translumina GmbH). Concentrations were 2, 2 Multiplication-Sign 2, 3, and 4 %. Measurements regarding the amount of substance released to the vessel wall were carried out on explanted porcine coronaries by means of ultraviolet and visible-light spectroscopy. Inflation time varied between 30 and 120 s. The biological effect of the coating was evaluated in a porcine peripheral overstretch and stent implantation model. Results. The amount of rapamycin on the balloon surface ranged from 558 {+-} 108 {mu}g for the 2 % solution to 1,441 {+-} 228 {mu}g in the 4 % solution. An amount of 95 {+-} 63-193 {+-} 113 {mu}g was released into the vessel wall. The quantitative measurements of the angiographic examinations 4 weeks after treatment revealed a reduction of diameter stenosis from 20.6 {+-} 17.4 % in the control group to 11.6 {+-} 5.5 % in the drug-eluting balloon group. Conclusion. A balloon coating with rapamycin omitting an excipient is possible with a dose-adjustable coating machine. However, the biological effects are moderate, which make further optimization of the coating process and evaluation of appropriate excipients necessary.

  9. Metabolic effects of acute thiamine depletion are reversed by rapamycin in breast and leukemia cells.

    Directory of Open Access Journals (Sweden)

    Shuqian Liu

    Full Text Available Thiamine-dependent enzymes (TDEs control metabolic pathways that are frequently altered in cancer and therefore present cancer-relevant targets. We have previously shown that the recombinant enzyme thiaminase cleaves and depletes intracellular thiamine, has growth inhibitory activity against leukemia and breast cancer cell lines, and that its growth inhibitory effects were reversed in leukemia cell lines by rapamycin. Now, we first show further evidence of thiaminase therapeutic potential by demonstrating its activity against breast and leukemia xenografts, and against a primary leukemia xenograft. We therefore further explored the metabolic effects of thiaminase in combination with rapamycin in leukemia and breast cell lines. Thiaminase decreased oxygen consumption rate and increased extracellular acidification rate, consistent with the inhibitory effect of acute thiamine depletion on the activity of the TDEs pyruvate dehydrogenase and 2-oxoglutarate dehydrogenase complexes; these effects were reversed by rapamycin. Metabolomic studies demonstrated intracellular thiamine depletion and the presence of the thiazole cleavage product in thiaminase-treated cells, providing validation of the experimental procedures. Accumulation of ribose and ribulose in both cell lines support the thiaminase-mediated suppression of the TDE transketolase. Interestingly, thiaminase suppression of another TDE, branched chain amino ketoacid dehydrogenase (BCKDH, showed very different patterns in the two cell lines: in RS4 leukemia cells it led to an increase in BCKDH substrates, and in MCF-7 breast cancer cells it led to a decrease in BCKDH products. Immunoblot analyses showed corresponding differences in expression of BCKDH pathway enzymes, and partial protection of thiaminase growth inhibition by gabapentin indicated that BCKDH inhibition may be a mechanism of thiaminase-mediated toxicity. Surprisingly, most of thiaminase-mediated metabolomic effects were also

  10. Combination therapy for inhibitor reversal in haemophilia A using monoclonal anti-CD20 and rapamycin.

    Science.gov (United States)

    Biswas, Moanaro; Rogers, Geoffrey L; Sherman, Alexandra; Byrne, Barry J; Markusic, David M; Jiang, Haiyan; Herzog, Roland W

    2017-01-05

    Development of antibodies (inhibitors) against coagulation factor VIII (FVIII) is a major complication of intravenous replacement therapy in haemophilia A (HA). Current immune tolerance induction (ITI) regimens are not universally effective. Rituximab, a B cell-depleting antibody against CD20, has shown mixed results for inhibitor reversal in patients. This study aims to develop a combinatorial therapy for inhibitor reversal in HA, using anti-murine CD20 (anti-mCD20) antibody and rapamycin, which targets both B and T cell responses. Additionally, it extensively characterises the role of the IgG backbone in B cell depletion by anti-CD20 antibodies. For this, inhibitors were generated in BALB/c-HA mice by weekly IV injection of FVIII. Subsequently, anti-mCD20 (18B12) with IgG2a or IgG1 backbone was injected IV in two doses three weeks apart and B cell depletion and recovery was characterised. Rapamycin was administered orally 3x/week (for 1 month) while continuing FVIII injections. Altering the IgG backbone of anti-mCD20 from IgG2a to IgG1 reduced overall depletion of B cells (including memory B cells), and marginal zone, B-10, and B-1b cells were specifically unaffected. While neither antibody was effective alone, in combination with rapamycin, anti-mCD20 IgG2a but not IgG1 was able to reverse inhibitors in HA mice. This regimen was particularly effective for starting titres of ~10 BU. Although IgG1 anti-mCD20 spared potentially tolerogenic B cell subsets, IgG2a directed sustained hyporesponsiveness when administered in conjunction with rapamycin. This regimen represents a promising treatment for inhibitor reversal in HA, as both of these compounds have been extensively used in human patients.

  11. Dysregulation of Mammalian Target of Rapamycin Signaling in Mouse Models of Autism

    OpenAIRE

    Huber, Kimberly M.; Klann, Eric; Costa-Mattioli, Mauro; Zukin, R. Suzanne

    2015-01-01

    The mammalian target of rapamycin (mTOR) is a central regulator of a diverse array of cellular processes, including cell growth, proliferation, autophagy, translation, and actin polymerization. Components of the mTOR cascade are present at synapses and influence synaptic plasticity and spine morphogenesis. A prevailing view is that the study of mTOR and its role in autism spectrum disorders (ASDs) will elucidate the molecular mechanisms by which mTOR regulates neuronal function under physiolo...

  12. Topical application of rapamycin ointment ameliorates Dermatophagoides farina body extract-induced atopic dermatitis in NC/Nga mice.

    Science.gov (United States)

    Yang, Fei; Tanaka, Mari; Wataya-Kaneda, Mari; Yang, Lingli; Nakamura, Ayumi; Matsumoto, Shoji; Attia, Mostafa; Murota, Hiroyuki; Katayama, Ichiro

    2014-08-01

    Atopic dermatitis (AD), a chronic inflammatory skin disease characterized by relapsing eczema and intense prurigo, requires effective and safe pharmacological therapy. Recently, rapamycin, an mTOR (mammalian target of rapamycin) inhibitor, has been reported to play a critical role in immune responses and has emerged as an effective immunosuppressive drug. In this study, we assessed whether inhibition of mTOR signalling could suppress dermatitis in mice. Rapamycin was topically applied to inflamed skin in a murine AD model that was developed by repeated topical application of Dermatophagoides farina body (Dfb) extract antigen twice weekly for 7 weeks in NC/Nga mice. The efficacy of topical rapamycin treatment was evaluated immunologically and serologically. Topical application of rapamycin reduced inflammatory cell infiltration in the dermis, alleviated the increase of serum IgE levels and resulted in a significant reduction in clinical skin condition score and marked improvement of histological findings. In addition, increased mTOR phosphorylation in the lesional skin was observed in our murine AD model. Topical application of rapamycin ointment inhibited Dfb antigen-induced dermatitis in NC/Nga mice, promising a new therapy for atopic dermatitis. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Rapamycin Eye Drops Suppress Lacrimal Gland Inflammation In a Murine Model of Sjögren's Syndrome

    Science.gov (United States)

    Shah, Mihir; Edman, Maria C.; Reddy Janga, Srikanth; Yarber, Frances; Meng, Zhen; Klinngam, Wannita; Bushman, Jonathan; Ma, Tao; Liu, Siyu; Louie, Stan; Mehta, Arjun; Ding, Chuanqing; MacKay, J. Andrew; Hamm-Alvarez, Sarah F.

    2017-01-01

    Purpose To evaluate the efficacy of topical rapamycin in treating autoimmune dacryoadenitis in a mouse model of Sjögren's syndrome. Methods We developed rapamycin in a poly(ethylene glycol)-distearoyl phosphatidylethanolamine (PEG-DSPE) micelle formulation to maintain solubility. Rapamycin or PEG-DSPE eye drops (vehicle) were administered in a well-established Sjögren's syndrome disease model, the male nonobese diabetic (NOD) mice, twice daily for 12 weeks starting at 8 weeks of age. Mouse tear fluid was collected and tear Cathepsin S, a putative tear biomarker for Sjögren's syndrome, was measured. Lacrimal glands were retrieved for histological evaluation, and quantitative real-time PCR of genes associated with Sjögren's syndrome pathogenesis. Tear secretion was measured using phenol red threads, and corneal fluorescein staining was used to assess corneal integrity. Results Lymphocytic infiltration of lacrimal glands from rapamycin-treated mice was significantly (P = 0.0001) reduced by 3.8-fold relative to vehicle-treated mice after 12 weeks of treatment. Rapamycin, but not vehicle, treatment increased tear secretion and decreased corneal fluorescein staining after 12 weeks. In rapamycin-treated mice, Cathepsin S activity was significantly reduced by 3.75-fold in tears (P eye. PMID:28122086

  14. Low-Dose Rapamycin Treatment Increases the Ability of Human Regulatory T Cells to Inhibit Transplant Arteriosclerosis In Vivo

    Science.gov (United States)

    Hester, J; Schiopu, A; Nadig, S N; Wood, K J

    2012-01-01

    Regulatory T cells (Treg) are currently being tested in clinical trials as a potential therapy in cell and solid organ transplantation. The immunosuppressive drug rapamycin has been shown to preferentially promote Treg expansion. Here, we hypothesized that adjunctive rapamycin therapy might potentiate the ability of ex vivo expanded human Treg to inhibit vascular allograft rejection in a humanized mouse model of arterial transplantation. We studied the influence of combined treatment with low-dose rapamycin and subtherapeutic Treg numbers on the development of transplant arteriosclerosis (TA) in human arterial grafts transplanted into immunodeficient BALB/cRag2−/−Il2rg−/− mice reconstituted with allogeneic human peripheral blood mononuclear cell. In addition, we assessed the effects of the treatment on the proliferation and apoptosis of naïve/effector T cells. The combined therapy efficiently suppressed T-cell proliferation in vivo and in vitro. Neointima formation in the human arterial allografts was potently inhibited compared with each treatment alone. Interestingly, CD4+ but not CD8+ T lymphocytes were sensitive to Treg and rapamycin-induced apoptosis in vitro. Our data support the concept that rapamycin can be used as an adjunctive therapy to improve efficacy of Treg-based immunosuppressive protocols in clinical practice. By inhibiting TA, Treg and rapamycin may prevent chronic transplant dysfunction and improve long-term allograft survival PMID:22500984

  15. Addition of rapamycin to anti-CD3 antibody improves long-term glycaemia control in diabetic NOD mice.

    Directory of Open Access Journals (Sweden)

    Shira Perl

    Full Text Available Non-Fc-binding Anti CD3 antibody has proven successful in reverting diabetes in the non-obese diabetes mouse model of type 1 diabetes and limited efficacy has been observed in human clinical trials. We hypothesized that addition of rapamycin, an mTOR inhibitor capable of inducing operational tolerance in allogeneic bone marrow transplantation, would result in improved diabetes reversal rates and overall glycemia.Seventy hyperglycemic non-obese diabetic mice were randomized to either a single injection of anti CD3 alone or a single injection of anti CD3 followed by 14 days of intra-peritoneal rapamycin. Mice were monitored for hyperglycemia and metabolic control.Mice treated with the combination of anti CD3 and rapamycin had similar rates of diabetes reversal compared to anti CD3 alone (25/35 vs. 22/35. Mice treated with anti CD3 plus rapamycin had a significant improvement in glycemia control as exhibited by lower blood glucose levels in response to an intra-peritoneal glucose challenge; average peak blood glucose levels 30 min post intra-peritoneal injection of 2 gr/kg glucose were 6.9 mmol/L in the anti CD3 plus rapamycin group vs. 10 mmo/L in the anti CD3 alone (P<0.05.The addition of rapamycin to anti CD3 results in significant improvement in glycaemia control in diabetic NOD mice.

  16. Basic Concepts in G-Protein-Coupled Receptor Homo- and Heterodimerization

    Directory of Open Access Journals (Sweden)

    Rafael Franco

    2007-01-01

    Full Text Available Until recently, heptahelical G-protein-coupled receptors (GPCRs were considered to be expressed as monomers on the cell surface of neuronal and non-neuronal cells. It is now becoming evident that this view must be overtly changed since these receptors can form homodimers, heterodimers, and higher-order oligomers on the plasma membrane. Here we discuss some of the basics and some new concepts of receptor homo- and heteromerization. Dimers-oligomers modify pharmacology, trafficking, and signaling of receptors. First of all, GPCR dimers must be considered as the main molecules that are targeted by neurotransmitters or by drugs. Thus, binding data must be fitted to dimer-based models. In these models, it is considered that the conformational changes transmitted within the dimer molecule lead to cooperativity. Cooperativity must be taken into account in the binding of agonists-antagonists-drugs and also in the binding of the so-called allosteric modulators. Cooperativity results from the intramolecular cross-talk in the homodimer. As an intramolecular cross-talk in the heterodimer, the binding of one neurotransmitter to one receptor often affects the binding of the second neurotransmitter to the partner receptor. Coactivation of the two receptors in a heterodimer can change completely the signaling pathway triggered by the neurotransmitter as well as the trafficking of the receptors. Heterodimer-specific drugs or dual drugs able to activate the two receptors in the heterodimer simultaneously emerge as novel and promising drugs for a variety of central nervous system (CNS therapeutic applications.

  17. Progeroid syndrome patients with ZMPSTE24 deficiency could benefit when treated with rapamycin and dimethylsulfoxide

    Science.gov (United States)

    Akinci, Baris; Sankella, Shireesha; Gilpin, Christopher; Ozono, Keiichi; Garg, Abhimanyu; Agarwal, Anil K.

    2017-01-01

    Patients with progeroid syndromes such as mandibuloacral dysplasia, type B (MADB) and restrictive dermopathy (RD) harbor mutations in zinc metalloproteinase (ZMPSTE24), an enzyme essential for posttranslational proteolysis of prelamin A to form mature lamin A. Dermal fibroblasts from these patients show increased nuclear dysmorphology and reduced proliferation; however, the efficacy of various pharmacological agents in reversing these cellular phenotypes remains unknown. In this study, fibroblasts from MADB patients exhibited marked nuclear abnormalities and reduced proliferation that improved upon treatment with rapamycin and dimethylsulfoxide but not with other agents, including farnesyl transferase inhibitors. Surprisingly, fibroblasts from an RD patient with a homozygous null mutation in ZMPSTE24, resulting in exclusive accumulation of prelamin A with no lamin A on immunoblotting of cellular lysate, exhibited few nuclear abnormalities and near-normal cellular proliferation. An unbiased proteomic analysis of the cellular lysate from RD fibroblasts revealed a lack of processing of vimentin, a cytoskeletal protein. Interestingly, the assembly of the vimentin microfibrils in MADB fibroblasts improved with rapamycin and dimethylsulfoxide. We conclude that rapamycin and dimethylsulfoxide are beneficial for improving nuclear morphology and cell proliferation of MADB fibroblasts. Data from a single RD patient's fibroblasts also suggest that prelamin A accumulation by itself might not be detrimental and requires additional alterations at the cellular level to manifest the phenotype. PMID:28050601

  18. Activation of the unfolded protein response in sarcoma cells treated with rapamycin or temsirolimus.

    Science.gov (United States)

    Briggs, Joseph W; Ren, Ling; Chakrabarti, Kristi R; Tsai, Yien Che; Weissman, Allan M; Hansen, Ryan J; Gustafson, Daniel L; Khan, Yousuf A; Dinman, Jonathan D; Khanna, Chand

    2017-01-01

    Activation of the unfolded protein response (UPR) in eukaryotic cells represents an evolutionarily conserved response to physiological stress. Here, we report that the mTOR inhibitors rapamycin (sirolimus) and structurally related temsirolimus are capable of inducing UPR in sarcoma cells. However, this effect appears to be distinct from the classical role for these drugs as mTOR inhibitors. Instead, we detected these compounds to be associated with ribosomes isolated from treated cells. Specifically, temsirolimus treatment resulted in protection from chemical modification of several rRNA residues previously shown to bind rapamycin in prokaryotic cells. As an application for these findings, we demonstrate maximum tumor cell growth inhibition occurring only at doses which induce UPR and which have been shown to be safely achieved in human patients. These results are significant because they challenge the paradigm for the use of these drugs as anticancer agents and reveal a connection to UPR, a conserved biological response that has been implicated in tumor growth and response to therapy. As a result, eIF2 alpha phosphorylation and Xbp-1 splicing may serve as useful biomarkers of treatment response in future clinical trials using rapamycin and rapalogs.

  19. Effects of Rapamycin Combined with Low Dose Prednisone in Patients with Chronic Immune Thrombocytopenia

    Directory of Open Access Journals (Sweden)

    Jiaming Li

    2013-01-01

    Full Text Available We conducted this randomized trial to investigate the efficacy and safety of rapamycin treatment in adults with chronic immune thrombocytopenia (ITP. Eighty-eight patients were separated into the control (cyclosporine A plus prednisone and experimental (rapamycin plus prednisone groups. The CD4+CD25+CD127low regulatory T (Treg cells level, Foxp3 mRNA expression, and the relevant cytokines levels were measured before and after treatment. The overall response (OR was similar in both groups (experimental group versus control group: 58% versus 62%, P=0.70. However, sustained response (SR was more pronounced in the experimental group than in the control group (68% versus 39%, P<0.05. Both groups showed similar incidence of adverse events (7% versus 11%, P=0.51. As expected, the low pretreatment baseline level of Treg cells was seen in all patients (P<0.001; however, the experimental group experienced a significant rise in Treg cell level, and there was a strong correlation between the levels of Treg cells and TGF-beta after the treatment. In addition, the upregulation maintained a stable level during the follow-up phase. Thus, rapamycin plus low dose prednisone could provide a new promising option for therapy of ITP.

  20. Activation of the unfolded protein response in sarcoma cells treated with rapamycin or temsirolimus.

    Directory of Open Access Journals (Sweden)

    Joseph W Briggs

    Full Text Available Activation of the unfolded protein response (UPR in eukaryotic cells represents an evolutionarily conserved response to physiological stress. Here, we report that the mTOR inhibitors rapamycin (sirolimus and structurally related temsirolimus are capable of inducing UPR in sarcoma cells. However, this effect appears to be distinct from the classical role for these drugs as mTOR inhibitors. Instead, we detected these compounds to be associated with ribosomes isolated from treated cells. Specifically, temsirolimus treatment resulted in protection from chemical modification of several rRNA residues previously shown to bind rapamycin in prokaryotic cells. As an application for these findings, we demonstrate maximum tumor cell growth inhibition occurring only at doses which induce UPR and which have been shown to be safely achieved in human patients. These results are significant because they challenge the paradigm for the use of these drugs as anticancer agents and reveal a connection to UPR, a conserved biological response that has been implicated in tumor growth and response to therapy. As a result, eIF2 alpha phosphorylation and Xbp-1 splicing may serve as useful biomarkers of treatment response in future clinical trials using rapamycin and rapalogs.

  1. Myxoma virus combined with rapamycin treatment enhances adoptive T cell therapy for murine melanoma brain tumors.

    Science.gov (United States)

    Thomas, Diana L; Doty, Rosalinda; Tosic, Vesna; Liu, Jia; Kranz, David M; McFadden, Grant; Macneill, Amy L; Roy, Edward J

    2011-10-01

    Adoptive transfer of tumor-specific T cells has shown some success for treating metastatic melanoma. We evaluated a novel strategy to improve adoptive therapy by administering both T cells and oncolytic myxoma virus to mice with syngeneic B16.SIY melanoma brain tumors. Adoptive transfer of activated CD8(+) 2C T cells that recognize SIY peptide doubled survival time, but SIY-negative tumors recurred. Myxoma virus killed B16.SIY cells in vitro, and intratumoral injection of virus led to selective and transient infection of the tumor. Virus treatment recruited innate immune cells to the tumor and induced IFNβ production in the brain, resulting in limited oncolytic effects in vivo. To counter this, we evaluated the safety and efficacy of co-administering 2C T cells, myxoma virus, and either rapamycin or neutralizing antibodies against IFNβ. Mice that received either triple combination therapy survived significantly longer with no apparent side effects, but eventually relapsed. Importantly, rapamycin treatment did not impair T cell-mediated tumor destruction, supporting the feasibility of combining adoptive immunotherapy and rapamycin-enhanced virotherapy. Myxoma virus may be a useful vector for transient delivery of therapeutic genes to a tumor to enhance T cell responses.

  2. p21WAF1/CIP1 Expression is Differentially Regulated by Metformin and Rapamycin

    Directory of Open Access Journals (Sweden)

    Zoltan Molnar

    2014-01-01

    Full Text Available The mammalian target of rapamycin (mTOR pathway plays an important role in the development of diabetic nephropathy and other age-related diseases. One of the features of DN is the elevated expression of p21WAF1/CIP1. However, the importance of the mTOR signalling pathway in p21 regulation is poorly understood. Here we investigated the effect of metformin and rapamycin on mTOR-related phenotypes in cell lines of epithelial origin. This study reports that metformin inhibits high glucose-induced p21 expression. High glucose opposed metformin in regulating cell size, proliferation, and protein synthesis. These effects were associated with reduced AMPK activation, affecting downstream mTOR signalling. However, the inhibition of the mTOR pathway by rapamycin did not have a negative effect on p21 expression, suggesting that metformin regulates p21 upstream of mTOR. These findings provide support for the hypothesis that AMPK activation may regulate p21 expression, which may have implications for diabetic nephropathy and other age-related pathologies.

  3. Folding of bacterial luciferase involves a non-native heterodimeric intermediate in equilibrium with the native enzyme and the unfolded subunits.

    Science.gov (United States)

    Clark, A C; Sinclair, J F; Baldwin, T O

    1993-05-25

    Bacterial luciferase is a heterodimeric enzyme that catalyzes the reaction of reduced FMN, O2 and an aliphatic aldehyde to yield the carboxylic acid and an excited flavin that emits blue-green light upon return to ground state. The two subunits of the luciferase from Vibrio harveyi, alpha and beta, have molecular weights of 40,108 and 36.349, respectively; the single active center resides primarily, if not exclusively, on the alpha subunit. We have found that bacterial luciferase can be unfolded in urea-containing 50 mM phosphate buffer, pH 7.0, and refolded by dilution of the urea with final luciferase concentrations of 5-25 micrograms/ml. We have analyzed the urea-induced equilibrium unfolding of bacterial luciferase by monitoring changes in both the far ultraviolet circular dichroism (predominantly secondary structure) and intrinsic fluorescence emission (predominantly tertiary structure) resulting from incubation in various concentrations of urea at 18 degrees C for 18-24 h. Both spectral methods indicated a biphasic unfolding transition; the first phase was protein concentration-independent, whereas the second phase was protein concentration-dependent. Equilibrium unfolding curves showed an increase in fluorescence up to 2 M urea followed by a decrease in intensity and red shift of the emission maximum. The ratio of the fluorescence emission in the presence of 2 M urea relative to that in the absence of urea was greater when fluorescence was excited at 295 nm than at 280 nm. The fluorescence increase in the 0-2 M urea range corresponded to the first phase of the biphasic unfolding process. The urea-induced loss of luciferase enzymatic activity appeared to correspond to the first transition observed with the spectroscopic methods, and likewise to be protein concentration-independent. These observations suggested a three-state unfolding mechanism in which the native heterodimeric enzyme rearranges to an inactive heterodimeric species that is well populated

  4. 18F, 64Cu, and 68Ga labeled RGD-bombesin heterodimeric peptides for PET imaging of breast cancer

    Science.gov (United States)

    Liu, Zhaofei; Yan, Yongjun; Liu, Shuanglong; Wang, Fan; Chen, Xiaoyuan

    2010-01-01

    Radiolabeled RGD and bombesin (BBN) radiotracers that specifically target integrin αvβ3 and gastrin releasing peptide receptor (GRPR) are both promising radiopharmaceuticals for tumor imaging. We recently designed and synthesized a RGD-BBN heterodimeric peptide with both RGD and BBN motifs in one single molecule. The 18F-labeled RGD-BBN heterodimer exhibited dual integrin αvβ3 and GRPR targeting in a PC-3 prostate cancer model. In this study we investigated whether radiolabeled RGD-BBN tracers can be used to detect breast cancer by using microPET. Cell binding assay demonstrated that the high GRPR expressing breast cancer cells typically express low to moderate level of integrin αvβ3, while high integrin αvβ3 expressing breast cancer cells have negligible level of GRPR. We labeled RGD-BBN heterodimer with three positron emitting radionuclides 18F, 64Cu and 68Ga, and investigated the corresponding PET radiotracers in both orthotopic T47D (GRPR+/low integrin αvβ3) and MDA-MB-435 (GRPR−/integrin αvβ3+) breast cancer models. The three radiotracers all possessed in vitro dual integrin αvβ3 and GRPR binding affinity. The advantages of the RGD-BBN radiotracers over the corresponding BBN analogues are obvious for imaging MDA-MB-435 (GRPR−/integrin αvβ3+) tumor. 18F-FB-PEG3-RGD-BBN showed lower tumor uptake than 64Cu-NOTA-RGD-BBN and 68Ga-NOTA-RGD-BBN but was able to visualize breast cancer tumors with high contrast. Synthesis of 64Cu-NOTA-RGD-BBN and 68Ga-NOTA-RGD-BBN is much faster and easier than 18F-FB-PEG3-RGD-BBN. 64Cu-NOTA-RGD-BBN showed prolonged tumor uptake, but also higher liver retention and kidney uptake than 68Ga-NOTA-RGD-BBN and 18F-FB-PEG3-RGD-BBN. 68Ga-NOTA-RGD-BBN possessed high tumor signals, but also relatively high background uptake as compared with the other two radiotracers. In summary, the prosthetic labeling groups, chelators and isotopes all have profound effect on the tumor targeting efficacy and in vivo kinetics of the RGD

  5. Effects of rapamycin and curcumin treatment on the development of epilepsy after electrically induced status epilepticus in rats.

    Science.gov (United States)

    Drion, Cato M; Borm, Lars E; Kooijman, Lieneke; Aronica, Eleonora; Wadman, Wytse J; Hartog, Aloysius F; van Vliet, Erwin A; Gorter, Jan A

    2016-05-01

    Inhibition of the mammalian target of rapamycin (mTOR) pathway has been suggested as a possible antiepileptogenic strategy in temporal lobe epilepsy (TLE). Here we aim to elucidate whether mTOR inhibition has antiepileptogenic and/or antiseizure effects using different treatment strategies in the electrogenic post-status epilepticus (SE) rat model. Effects of mTOR inhibitor rapamycin were tested using the following three treatment protocols: (1) "stop-treatment"-post-SE treatment (6 mg/kg/day) was discontinued after 3 weeks; rats were monitored for 5 more weeks thereafter, (2) "pretreatment"-rapamycin (3 mg/kg/day) was applied during 3 days preceding SE; and (3) "chronic phase-treatment"-5 days rapamycin treatment (3 mg/kg/day) in the chronic phase. We also tested curcumin, an alternative mTOR inhibitor with antiinflammatory and antioxidant effects, using chronic phase treatment. Seizures were continuously monitored using video-electroencephalography (EEG) recordings; mossy fiber sprouting, cell death, and inflammation were studied using immunohistochemistry. Blood was withdrawn regularly to assess rapamycin and curcumin levels with high performance liquid chromatography (HPLC). Stop-treatment led to a strong reduction of seizures during the 3-week treatment and a gradual reappearance of seizures during the following 5 weeks. Three days pretreatment did not prevent seizure development, whereas 5-day rapamycin treatment in the chronic phase reduced seizure frequency. Washout of rapamycin was slow and associated with a gradual reappearance of seizures. Rapamycin treatment (both 3 and 6 mg/kg) led to body growth reduction. Curcumin treatment did not reduce seizure frequency or lead to a decrease in body weight. The present study indicates that rapamycin cannot prevent epilepsy in the electrical stimulation post-SE rat model but has seizure-suppressing properties as long as rapamycin blood levels are sufficiently high. Oral curcumin treatment had no effect on chronic

  6. Isoimperatorin ameliorates osteoarthritis by downregulating the mammalian target of rapamycin C1 signaling pathway.

    Science.gov (United States)

    Ouyang, Jiayao; Jiang, Huaji; Fang, Hang; Cui, Wenbo; Cai, Daozhang

    2017-12-01

    Osteoarthritis (OA) is the most common disease of the joints, and is characterized by the breakdown of cartilage and degradation of the extracellular matrix. OA causes a high level of patient suffering and incurs large societal costs; however, the current strategies for treating OA are restricted due to limited understanding of the underlying molecular and cellular mechanisms. In the present study, the beneficial effects of isoimperatorin (Iso) were investigated using an experimental mouse model of OA, and its mechanism of action on primary chondrocytes was elucidated. Destabilization of the medial meniscus was performed on 8‑week‑old male mice to induce OA in the knees. Iso (500 mg/g/day) was intragastrically administered for 4 weeks. Degeneration of articular cartilage was assessed by histology using the Osteoarthritis Research Society International scoring system. The expression of matrix metalloproteinase (MMP)13, Runt‑related transcription factor (Runx)2, type X collagen (Col X) and vascular endothelial growth factor (VEGF) in the knee joints was examined by immunohistochemistry. In vitro, murine primary chondrocytes were treated with various concentrations of Iso, followed by 10 ng/ml interleukin‑1. The mRNA expression levels of MMP13, Runx2, Col X and VEGF were determined by reverse transcription‑quantitative polymerase chain reaction. The levels of autophagy and mammalian target of rapamycin (mTOR) signaling were determined by western blotting. Iso significantly ameliorated the severity of articular cartilage degradation in mice with experimental OA. The expression levels of MMP13, Runx2, Col X and VEGF were reduced in Iso‑treated mice. In murine primary chondrocytes, Iso also reduced MMP13, Runx2, Col X and VEGF expression, and activated autophagy by downregulating the mTOR complex 1 (mTORC1) signaling pathway. Therefore, the results of the present study demonstrated that Iso ameliorates OA‑induced pathological alterations by delaying

  7. Inhibition of p70S6K does not mimic the enhancement of Akt phosphorylation by rapamycin.

    Science.gov (United States)

    Wang, Xuerong; Yue, Ping; Tao, Hui; Sun, Shi-Yong

    2017-08-01

    It has been suggested that the mTOR complex 1 (mTORC1)/p70S6K axis represses upstream PI3K/Akt signaling through phosphorylation of IRS-1 and its subsequent degradation. One potential and current model that explains Akt activation induced by the mTOR inhibitor rapamycin is the relief of mTORC1/p70S6K-mediated feedback inhibition of IRS-1/PI3K/Akt signaling, although this has not been experimentally proven. In this study, we found that chemical inhibition of p70S6K did not increase Akt phosphorylation. Surprisingly, knockdown of p70S6K even substantially inhibited Akt phosphorylation. Hence, p70S6K inhibition clearly does not mimic the activation of Akt by rapamycin. Inhibition or enforced activation of p70S6K did not affect the ability of rapamycin to increase Akt phosphorylation. Moreover, inhibition of mTORC1 with either rapamycin or raptor knockdown did not elevate IRS-1 levels, despite potently increasing Akt phosphorylation. Critically, knockdown or knockout of IRS-1 or IRS-2 failed to abolish the ability of rapamycin to increase Akt phosphorylation. Therefore, IRS-1 and IRS-2 are not essential for mediating rapamycin-induced Akt activation. Collectively, our findings suggest that Akt activation by rapamycin or mTORC1 inhibition is unlikely due to relief of p70S6K-mediated feedback inhibition of IRS-1/PI3K/Akt signaling.

  8. Rapamycin-loaded Immunoliposomes Functionalized with Trastuzumab: A Strategy to Enhance Cytotoxicity to HER2-positive Breast Cancer Cells.

    Science.gov (United States)

    Eloy, Josimar O; Petrilli, Raquel; Brueggemeier, Robert W; Marchetti, Juliana Maldonado; Lee, Robert J

    2017-01-01

    Liposomes have been employed to improve pharmacokinetics and reduce side effects of drugs. They can be functionalized with antibodies for targeted delivery. While the monoclonal antibody trastuzumab has been employed in the therapy of HER2-positive breast cancer, the resistance developed during treatment has been reported. Rapamycin could be used in combination with trastuzumab for improved therapeutic response. In this study, we aimed to develop rapamycin-loaded liposomes and immunoliposomes with trastuzumab, characterize them and evaluate their in vitro cytotoxicity. Formulations were prepared by the thin film hydration method and immunoliposome was conjugated to antibody by covalent bond. Characterization involved particle size, polydispersity, zeta potential, encapsulation efficiency, functionalization efficiency, DSC and FTIR assays. Cell studies were conducted through the MTT assay. SPC:Chol:DSPE-PEG formulation prepared at 1:10 drug to lipid ratio presented high encapsulation efficiency, appropriate particle size, low polydispersity, negative zeta potential and colloidal stability. Rapamycin exhibited intermolecular interactions with lipids and underwent crystallinity reduction. Rapamycin-loaded immunoliposomes were prepared with high trastuzumab functionalization efficiency and antibody stability. Cytotoxicity studies showed that the HER2-positive SK-BR-3 cell line was sensitive to trastuzumab, either as free drug or in the context of immunoliposomes, and is more sensitive to rapamycin than the triple negative MDA-MB-231 cells. For MDA-MB-231, the liposomal rapamycin was more cytotoxic than the free drug. Furthermore, the immunoliposomes showed potent cytotoxicity against SK-BR-3 cells. Finally, rapamycin and trastuzumab exhibited in vitro synergistic effect, particularly through immunoliposomes. The formulation developed herein has potential for in vivo evaluation.

  9. Acremoxanthone E, a novel member of heterodimeric polyketides with a bicyclo[3.2.2]nonene ring, produced by Acremonium camptosporum W. GAMS (Clavicipitaceae) endophytic fungus.

    Science.gov (United States)

    Meléndez-González, Claudio; Murià-González, M Jordi; Anaya, Ana Luisa; Hernández-Bautista, Blanca E; Hernández-Ortega, Simón; González, María C; Glenn, Anthony E; Hanlin, Richard T; Macías-Rubalcava, Martha L

    2015-01-01

    Bioactivity-directed fractionation of the organic mycelium extract of the endophytic fungus Acremonium camptosporum W. Gams (Clavicipitaceae), isolated from the leaves of Bursera simaruba (Burseraceae), led to the isolation of six major heterodimeric polyketides, including one not previously characterized acremoxanthone derivative. In addition, the already known acremoxanthone C, acremonidins A and B, and acremoxanthones A and B were obtained. The structure of the new compound was established by extensive NMR studies, including DEPT, COSY, NOESY, HSQC, and HMBC methods. The trivial name proposed for this compound is acremoxanthone E. In addition, the structure of acremoxanthone C was unequivocally established for the first time, through X-ray crystal-structure analysis. The anti-oomycete activities of the pure compounds were tested against four economically important phytopathogenic oomycetes. Inhibitory concentration for 50% diameter growth reduction, IC50 , values for the four phytopathogens ranged from 6 to 38 μM. Also, in parallel, the cytotoxic activities against six cancer cell lines were evaluated showing IC50 values similar to those of cisplatin. To the best of our knowledge, this is the first report on three different groups of heterodimeric polyketides, linked by a bicyclo[3.2.2]nonene, such as xanthoquinodins, acremonidins, and acremoxanthones, which are isolated from an endophytic fungus. In addition, a common biosynthetic origin could be proposed. Copyright © 2015 Verlag Helvetica Chimica Acta AG, Zürich.

  10. Crystallization and preliminary X-ray crystallographic analysis of the small subunit of the heterodimeric laccase POXA3b from Pleurotus ostreatus.

    Science.gov (United States)

    Ferraroni, Marta; Scozzafava, Andrea; Ullah, Sana; Tron, Thierry; Piscitelli, Alessandra; Sannia, Giovanni

    2014-01-01

    Laccases are multicopper oxidases of great biotechnological potential. While laccases are generally monomeric glycoproteins, the white-rot fungus Pleurotus ostreatus produces two closely related heterodimeric isoenzymes composed of a large subunit, homologous to the other fungal laccases, and a small subunit. The sequence of the small subunit does not show significant homology to any other protein or domain of known function and consequently its function is unknown. The highest similarity to proteins of known structure is to a putative enoyl-CoA hydratase/isomerase from Acinetobacter baumannii, which shows an identity of 27.8%. Diffraction-quality crystals of the small subunit of the heterodimeric laccase POXA3b (sPOXA3b) from P. ostreatus were obtained using the sitting-drop vapour-diffusion method at 294 K from a solution consisting of 1.8 M sodium formate, 0.1 M Tris-HCl pH 8.5. The crystals belonged to the tetragonal space group P4(1)2(1)2 or P4(3)2(1)2, with unit-cell parameters a = 126.6, c = 53.9 Å. The asymmetric unit contains two molecules related by a noncrystallographic twofold axis. A complete data set extending to a maximum resolution of 2.5 Å was collected at 100 K using a wavelength of 1.140 Å.

  11. Heterodimeric neurotoxic phospholipases A2--the first proteins from venom of recently established species Vipera nikolskii: implication of venom composition in viper systematics.

    Science.gov (United States)

    Ramazanova, Anna S; Zavada, Larisa L; Starkov, Vladislav G; Kovyazina, Irina V; Subbotina, Tatyana F; Kostyukhina, Ekaterina E; Dementieva, Irina N; Ovchinnikova, Tatiana V; Utkin, Yuri N

    2008-03-15

    For the first time the venom of recently established viper species Vipera nikolskii was fractionated and two heterodimeric phospholipases A(2) (HDP-1 and HDP-2) were isolated. Isolation of HDP-1 and HDP-2 is the first indication of the presence of two heterodimeric phospholipases A(2) in the venom of one viper species. When tested on the frog neuromuscular junction, isolated proteins affected neuromuscular transmission acting presynaptically. Using RP-HPLC, each heterodimer was separated into two monomeric subunits: basic phospholipase A(2) (HDP-1P and HDP-2P) and acidic component without enzymatic activity (HDP-In). The complete primary structures of subunits were deduced from corresponding sequences of cDNAs. The determined amino acid sequences were homologous to those of vipoxin from Vipera ammodytes and vaspin from Vipera aspis. Similar proteins were not found earlier in the well-studied venom of Vipera berus, the species from which V. nikolskii was recently separated. Our finding supports at the biochemical level the correctness of the establishment of V. nikolskii as an independent species. The finding of similar proteins (HDPs and vipoxin) in geographically remote species (V. nikolskii and V. ammodytes) corroborates the hypothesis about the pre-existence of genes encoding these proteins in all true viper species and their expression under certain conditions.

  12. OP16, a novel ent-kaurene diterpenoid, potentiates the antitumor effect of rapamycin by inhibiting rapamycin-induced feedback activation of Akt signaling in esophageal squamous cell carcinoma.

    Science.gov (United States)

    Peng, Ke-Zheng; Ke, Yu; Zhao, Qi; Tian, Fei; Liu, Hong-Min; Hou, Guiqin; Lu, Zhaoming

    2017-09-15

    Hyperactivation of mTOR signaling pathway has been viewed as a significant molecular pathogenesis of cancer. However, inhibition of mTOR by rapamycin and its analogs could induce numerous negative feedback loops to attenuate their therapeutic efficacy. As a traditional Chinese herbal medicine, Rabdosia rubescens has been used to treat esophageal squamous cell carcinoma (ESCC) for hundreds of years, and its major effective component is oridonin. Here we reported that OP16, a novel analog of oridonin, showed potent inhibition of cell proliferation and Akt phosphorylation in ESCC cells. The combination of OP16 and rapamycin possesses synergistic anti-proliferative and pro-apoptotic effects both in ESCC cells and ESCC xenografts, and no obvious adverse effect was observed in vivo. Mechanistic analysis revealed that OP16 could inhibit rapamycin-induced Akt activation through the p70S6K-mediated negative feedback loops, and the combination of OP16 and rapamycin was more effective in activating caspase-dependent apoptotic signaling cascade. This study supports the combined use of OP16 with rapamycin as a feasible and effective therapeutic approach for future treatment of ESCC. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Rapamycin targeting mTOR and hedgehog signaling pathways blocks human rhabdomyosarcoma growth in xenograft murine model

    Energy Technology Data Exchange (ETDEWEB)

    Kaylani, Samer Z. [Division of Hematology and Oncology, Department of Pediatrics, University of Alabama at Birmingham, 1600 7th Avenue South, ACC 414, Birmingham, AL 35233 (United States); Xu, Jianmin; Srivastava, Ritesh K. [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, 1530 3rd Avenue South, VH 509, Birmingham, AL 35294-0019 (United States); Kopelovich, Levy [Division of Cancer Prevention, National Cancer Institute, Bethesda (United States); Pressey, Joseph G. [Division of Hematology and Oncology, Department of Pediatrics, University of Alabama at Birmingham, 1600 7th Avenue South, ACC 414, Birmingham, AL 35233 (United States); Athar, Mohammad, E-mail: mathar@uab.edu [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, 1530 3rd Avenue South, VH 509, Birmingham, AL 35294-0019 (United States)

    2013-06-14

    Graphical abstract: Intervention of poorly differentiated RMS by rapamycin: In poorly differentiated RMS, rapamycin blocks mTOR and Hh signaling pathways concomitantly. This leads to dampening in cell cycle regulation and induction of apoptosis. This study provides a rationale for the therapeutic intervention of poorly differentiated RMS by treating patients with rapamycin alone or in combination with other chemotherapeutic agents. -- Highlights: •Rapamycin abrogates RMS tumor growth by modulating proliferation and apoptosis. •Co-targeting mTOR/Hh pathways underlie the molecular basis of effectiveness. •Reduction in mTOR/Hh pathways diminish EMT leading to reduced invasiveness. -- Abstract: Rhabdomyosarcomas (RMS) represent the most common childhood soft-tissue sarcoma. Over the past few decades outcomes for low and intermediate risk RMS patients have slowly improved while patients with metastatic or relapsed RMS still face a grim prognosis. New chemotherapeutic agents or combinations of chemotherapies have largely failed to improve the outcome. Based on the identification of novel molecular targets, potential therapeutic approaches in RMS may offer a decreased reliance on conventional chemotherapy. Thus, identification of effective therapeutic agents that specifically target relevant pathways may be particularly beneficial for patients with metastatic and refractory RMS. The PI3K/AKT/mTOR pathway has been found to be a potentially attractive target in RMS therapy. In this study, we provide evidence that rapamycin (sirolimus) abrogates growth of RMS development in a RMS xenograft mouse model. As compared to a vehicle-treated control group, more than 95% inhibition in tumor growth was observed in mice receiving parenteral administration of rapamycin. The residual tumors in rapamycin-treated group showed significant reduction in the expression of biomarkers indicative of proliferation and tumor invasiveness. These tumors also showed enhanced apoptosis

  14. Life-long rapamycin administration ameliorates age-dependent cognitive deficits by reducing IL-1β and enhancing NMDA signaling

    Science.gov (United States)

    Majumder, Smita; Caccamo, Antonella; Medina, David X.; Benavides, Adriana D.; Javors, Martin A.; Kraig, Ellen; Strong, Randy; Richardson, Arlan; Oddo, Salvatore

    2012-01-01

    Summary Understanding the factors that contribute to age-related cognitive decline is imperative, particularly as age is the major risk factor for several neurodegenerative disorders. Levels of several cytokines increase in the brain during aging, including IL-1β, whose levels positively correlate with cognitive deficits. Previous reports show that reducing the activity of the mammalian target of rapamycin (mTOR) extends lifespan in yeast, nematodes, Drosophila, and mice. It remains to be established, however, whether extending lifespan with rapamycin is accompanied by an improvement in cognitive function. In this study, we show that 18-month-old mice treated with rapamycin starting at two months of age perform significantly better on a task measuring spatial learning and memory compared to age-matched mice on the control diet. In contrast, rapamycin does not improve cognition when given to 15-month-old mice with pre-existing, age-dependent learning and memory deficits. We further show that the rapamycin-mediated improvement in learning and memory is associated with a decrease in IL-1β levels and an increase in NMDA signaling. This is the first evidence to show that a small molecule known to increase lifespan also ameliorates age-dependent learning and memory deficits. PMID:22212527

  15. Inhibition of mammalian target of rapamycin decreases intrarenal oxygen availability and alters glomerular permeability.

    Science.gov (United States)

    Sivertsson, Ebba; Friederich-Persson, Malou; Öberg, Carl M; Fasching, Angelica; Hansell, Peter; Rippe, Bengt; Palm, Fredrik

    2017-09-27

    Increased kidney oxygen consumption causing tissue hypoxia is suggested as a common pathway to chronic kidney disease. Mammalian target of rapamycin (mTOR) regulates cell proliferation and mitochondrial function. mTOR inhibitors, e.g. rapamycin, are used clinically to prevent graft rejection. mTOR has been identified as a key player in diabetes, which has stimulated the use of mTOR inhibitors to counter diabetic nephropathy. However, the effect of mTOR inhibition on kidney oxygen consumption is unknown. We therefore investigated the effects of mTOR inhibition on in vivo kidney function, oxygen homeostasis and glomerular permeability. Control and streptozotocin-induced diabetic rats were chronically treated with rapamycin and the functional consequences studied fourteen days thereafter. In both groups, mTOR inhibition induced mitochondrial uncoupling resulting in increased total kidney oxygen consumption and decreased intrarenal oxygen availability. Concomitantly, mTOR inhibition induced tubular injury, as estimated from urinary excretion of kidney injury molecule-1 (KIM-1), and reduced urinary protein excretion. The latter corresponded to reduced sieving coefficient for large molecules. In conclusion, mTOR inhibition induces mitochondrial dysfunction leading to decreased oxygen availability in normal and diabetic kidneys, which translates to increased KIM-1 in the urine. Reduced proteinuria after mTOR inhibition is an effect of reduced glomerular permeability for large molecules. Since hypoxia has been suggested as a common pathway to development of chronic kidney disease, mTOR inhibition to patients with pre-existing nephropathy should be used with caution since it may accelerate the progression of disease. Copyright © 2017, American Journal of Physiology-Renal Physiology.

  16. Mammalian target of rapamycin and the kidney. II. Pathophysiology and therapeutic implications.

    Science.gov (United States)

    Lieberthal, Wilfred; Levine, Jerrold S

    2012-07-15

    The mTOR pathway plays an important role in a number of common renal diseases, including acute kidney injury (AKI), diabetic nephropathy (DN), and polycystic kidney diseases (PKD). The activity of mTOR complex 1 (mTORC1) is necessary for renal regeneration and repair after AKI, and inhibition of mTORC1 by rapamycin has been shown to delay recovery from ischemic AKI in animal studies, and to prolong delayed graft function in humans who have received a kidney transplant. For this reason, administration of rapamycin should be delayed or discontinued in patients with AKI until full recovery of renal function has occurred. On the other hand, inappropriately high mTORC1 activity contributes to the progression of the metabolic syndrome, the development of type 2 diabetes, and the pathogenesis of DN. In addition, chronic hyperactivity of mTORC1, and possibly also mTORC2, contributes to cyst formation and enlargement in a number of forms of PKD. Inhibition of mTOR, using either rapamycin (which inhibits predominantly mTORC1) or "catalytic" inhibitors (which effectively inhibit both mTORC1 and mTORC2), provide exciting possibilities for novel forms of treatment of DN and PKD. In this second part of the review, we will examine the role of mTOR in the pathophysiology of DN and PKD, as well as the potential utility of currently available and newly developed inhibitors of mTOR to slow the progression of DN and/or PKD.

  17. Two mTOR inhibitors, rapamycin and Torin 1, differentially regulate iron-induced generation of mitochondrial ROS.

    Science.gov (United States)

    Huang, Hui; Chen, Jun; Lu, Huiru; Zhou, Mengxue; Chai, Zhifang; Hu, Yi

    2017-12-01

    It is generally believed that gene-environment interaction may contribute to neurodegeneration. Of particular note is that iron overload may be one of the risk factors for neurodegeneration. However, the mechanisms underlying iron-associated neurotoxicity are not fully understood. Here we explored the effects of mechanistic target of rapamycin (mTOR) inhibition in iron-stressed human neuroblastoma cells. Two mTOR inhibitors, rapamycin and Torin 1, had similar effects in cells exposed to a relatively low concentration of iron. At a higher concentration of iron, Torin 1, instead of rapamycin, could further aggravate iron-induced cytotoxicity, and mitochondrial ROS levels were significantly higher in Torin 1-treated cells. These results suggest that mTOR inhibition may not be able to alleviate iron-induced neurotoxicity.

  18. Deficiency of cardiac Acyl-CoA synthetase-1 induces diastolic dysfunction, but pathologic hypertrophy is reversed by rapamycin

    DEFF Research Database (Denmark)

    Paul, David S; Grevengoed, Trisha J; Pascual, Florencia

    2014-01-01

    In mice with temporally-induced cardiac-specific deficiency of acyl-CoA synthetase-1 (Acsl1(H-/-)), the heart is unable to oxidize long-chain fatty acids and relies primarily on glucose for energy. These metabolic changes result in the development of both a spontaneous cardiac hypertrophy...... of sarco/endoplasmic reticulum calcium ATPase and phospholamban showed no difference between genotypes. To determine the role of mTOR in the development of cardiac hypertrophy, we treated Acsl1(H-/-) mice with rapamycin. Six to eight week old Acsl1(H-/-) mice and their littermate controls were given i.......p. tamoxifen to eliminate cardiac Acsl1, then concomitantly treated for 10weeks with i.p. rapamycin or vehicle alone. Rapamycin completely blocked the enhanced ventricular S6K phosphorylation and cardiac hypertrophy and attenuated the expression of hypertrophy-associated fetal genes, including α-skeletal actin...

  19. Phosphoproteomic profiling of in vivo signaling in liver by the mammalian target of rapamycin complex 1 (mTORC1.

    Directory of Open Access Journals (Sweden)

    Gokhan Demirkan

    Full Text Available Our understanding of signal transduction networks in the physiological context of an organism remains limited, partly due to the technical challenge of identifying serine/threonine phosphorylated peptides from complex tissue samples. In the present study, we focused on signaling through the mammalian target of rapamycin (mTOR complex 1 (mTORC1, which is at the center of a nutrient- and growth factor-responsive cell signaling network. Though studied extensively, the mechanisms involved in many mTORC1 biological functions remain poorly understood.We developed a phosphoproteomic strategy to purify, enrich and identify phosphopeptides from rat liver homogenates. Using the anticancer drug rapamycin, the only known target of which is mTORC1, we characterized signaling in liver from rats in which the complex was maximally activated by refeeding following 48 hr of starvation. Using protein and peptide fractionation methods, TiO(2 affinity purification of phosphopeptides and mass spectrometry, we reproducibly identified and quantified over four thousand phosphopeptides. Along with 5 known rapamycin-sensitive phosphorylation events, we identified 62 new rapamycin-responsive candidate phosphorylation sites. Among these were PRAS40, gephyrin, and AMP kinase 2. We observed similar proportions of increased and reduced phosphorylation in response to rapamycin. Gene ontology analysis revealed over-representation of mTOR pathway components among rapamycin-sensitive phosphopeptide candidates.In addition to identifying potential new mTORC1-mediated phosphorylation events, and providing information relevant to the biology of this signaling network, our experimental and analytical approaches indicate the feasibility of large-scale phosphoproteomic profiling of tissue samples to study physiological signaling events in vivo.

  20. Enhancement of rapamycin production by metabolic engineering in Streptomyces hygroscopicus based on genome-scale metabolic model.

    Science.gov (United States)

    Dang, Lanqing; Liu, Jiao; Wang, Cheng; Liu, Huanhuan; Wen, Jianping

    2017-02-01

    Rapamycin, as a macrocyclic polyketide with immunosuppressive, antifungal, and anti-tumor activity produced by Streptomyces hygroscopicus, is receiving considerable attention for its significant contribution in medical field. However, the production capacity of the wild strain is very low. Hereby, a computational guided engineering approach was proposed to improve the capability of rapamycin production. First, a genome-scale metabolic model of Streptomyces hygroscopicus ATCC 29253 was constructed based on its annotated genome and biochemical information. The model consists of 1003 reactions, 711 metabolites after manual refinement. Subsequently, several potential genetic targets that likely guaranteed an improved yield of rapamycin were identified by flux balance analysis and minimization of metabolic adjustment algorithm. Furthermore, according to the results of model prediction, target gene pfk (encoding 6-phosphofructokinase) was knocked out, and target genes dahP (encoding 3-deoxy-D-arabino-heptulosonate-7-phosphate synthase) and rapK (encoding chorismatase) were overexpressed in the parent strain ATCC 29253. The yield of rapamycin increased by 30.8% by knocking out gene pfk and increased by 36.2 and 44.8% by overexpression of rapK and dahP, respectively, compared with parent strain. Finally, the combined effect of the genetic modifications was evaluated. The titer of rapamycin reached 250.8 mg/l by knockout of pfk and co-expression of genes dahP and rapK, corresponding to a 142.3% increase relative to that of the parent strain. The relationship between model prediction and experimental results demonstrates the validity and rationality of this approach for target identification and rapamycin production improvement.

  1. Rapamycin attenuates hypoxia-induced pulmonary vascular remodeling and right ventricular hypertrophy in mice

    Directory of Open Access Journals (Sweden)

    Tillmanns Harald H

    2007-02-01

    Full Text Available Abstract Background Chronic hypoxia induces pulmonary arterial hypertension (PAH. Smooth muscle cell (SMC proliferation and hypertrophy are important contributors to the remodeling that occurs in chronic hypoxic pulmonary vasculature. We hypothesized that rapamycin (RAPA, a potent cell cycle inhibitor, prevents pulmonary hypertension in chronic hypoxic mice. Methods Mice were held either at normoxia (N; 21% O2 or at hypobaric hypoxia (H; 0.5 atm; ~10% O2. RAPA-treated animals (3 mg/kg*d, i.p. were compared to animals injected with vehicle alone. Proliferative activity within the pulmonary arteries was quantified by staining for Ki67 (positive nuclei/vessel and media area was quantified by computer-aided planimetry after immune-labeling for α-smooth muscle actin (pixel/vessel. The ratio of right ventricle to left ventricle plus septum (RV/[LV+S] was used to determine right ventricular hypertrophy. Results Proliferative activity increased by 34% at day 4 in mice held under H (median: 0.38 compared to N (median: 0.28, p = 0.028 which was completely blocked by RAPA (median HO+RAPA: 0.23, p = 0.003. H-induced proliferation had leveled off within 3 weeks. At this time point media area had, however, increased by 53% from 91 (N to 139 (H, p Conclusion Therapy with rapamycin may represent a new strategy for the treatment of pulmonary hypertension.

  2. Chemical Genetics of Rapamycin-Insensitive TORC2 in S. cerevisiae

    Directory of Open Access Journals (Sweden)

    Joseph I. Kliegman

    2013-12-01

    Full Text Available Current approaches for identifying synergistic targets use cell culture models to see if the combined effect of clinically available drugs is better than predicted by their individual efficacy. New techniques are needed to systematically and rationally identify targets and pathways that may be synergistic targets. Here, we created a tool to screen and identify molecular targets that may synergize with new inhibitors of target of rapamycin (TOR, a conserved protein that is a major integrator of cell proliferation signals in the nutrient-signaling pathway. Although clinical results from TOR complex 1 (TORC1-specific inhibition using rapamycin analogs have been disappointing, trials using inhibitors that also target TORC2 have been promising. To understand this increased therapeutic efficacy and to discover secondary targets for combination therapy, we engineered Tor2 in S. cerevisiae to accept an orthogonal inhibitor. We used this tool to create a chemical epistasis miniarray profile (ChE-MAP by measuring interactions between the chemically inhibited Tor2 kinase and a diverse library of deletion mutants. The ChE-MAP identified known TOR components and distinguished between TORC1- and TORC2-dependent functions. The results showed a TORC2-specific interaction with the pentose phosphate pathway, a previously unappreciated TORC2 function that suggests a role for the complex in balancing the high energy demand required for ribosome biogenesis.

  3. A central role for the mammalian target of rapamycin in LPS-induced anorexia in mice.

    Science.gov (United States)

    Yue, Yunshuang; Wang, Yi; Li, Dan; Song, Zhigang; Jiao, Hongchao; Lin, Hai

    2015-01-01

    Bacterial lipopolysaccharide (LPS), also known as endotoxin, induces profound anorexia. However, the LPS-provoked pro-inflammatory signaling cascades and the neural mechanisms underlying the development of anorexia are not clear. Mammalian target of rapamycin (mTOR) is a key regulator of metabolism, cell growth, and protein synthesis. This study aimed to determine whether the mTOR pathway is involved in LPS-induced anorexia. Effects of LPS on hypothalamic gene/protein expression in mice were measured by RT-PCR or western blotting analysis. To determine whether inhibition of mTOR signaling could attenuate LPS-induced anorexia, we administered an i.c.v. injection of rapamycin, an mTOR inhibitor, on LPS-treated male mice. In this study, we showed that LPS stimulates the mTOR signaling pathway through the enhanced phosphorylation of mTOR(Ser2448) and p70S6K(Thr389). We also showed that LPS administration increased the phosphorylation of FOXO1(Ser256), the p65 subunit of nuclear factor kappa B (Panorexia by decreasing the phosphorylation of p70S6K(Thr389), FOXO1(Ser256), and FOXO1/3a(Thr) (24) (/) (32). These results suggest promising approaches for the prevention and treatment of LPS-induced anorexia. © 2015 Society for Endocrinology.

  4. Rapamycin Inhibits Proliferation of Hemangioma Endothelial Cells by Reducing HIF-1-Dependent Expression of VEGF

    Science.gov (United States)

    Medici, Damian; Olsen, Bjorn R.

    2012-01-01

    Hemangiomas are tumors formed by hyper-proliferation of vascular endothelial cells. This is caused by elevated vascular endothelial growth factor (VEGF) signaling through VEGF receptor 2 (VEGFR2). Here we show that elevated VEGF levels produced by hemangioma endothelial cells are reduced by the mTOR inhibitor rapamycin. mTOR activates p70S6K, which controls translation of mRNA to generate proteins such as hypoxia inducible factor-1 (HIF-1). VEGF is a known HIF-1 target gene, and our data show that VEGF levels in hemangioma endothelial cells are reduced by HIF-1α siRNA. Over-expression of HIF-1α increases VEGF levels and endothelial cell proliferation. Furthermore, both rapamycin and HIF-1α siRNA reduce proliferation of hemangioma endothelial cells. These data suggest that mTOR and HIF-1 contribute to hemangioma endothelial cell proliferation by stimulating an autocrine loop of VEGF signaling. Furthermore, mTOR and HIF-1 may be therapeutic targets for the treatment of hemangiomas. PMID:22900063

  5. Rapamycin inhibits proliferation of hemangioma endothelial cells by reducing HIF-1-dependent expression of VEGF.

    Directory of Open Access Journals (Sweden)

    Damian Medici

    Full Text Available Hemangiomas are tumors formed by hyper-proliferation of vascular endothelial cells. This is caused by elevated vascular endothelial growth factor (VEGF signaling through VEGF receptor 2 (VEGFR2. Here we show that elevated VEGF levels produced by hemangioma endothelial cells are reduced by the mTOR inhibitor rapamycin. mTOR activates p70S6K, which controls translation of mRNA to generate proteins such as hypoxia inducible factor-1 (HIF-1. VEGF is a known HIF-1 target gene, and our data show that VEGF levels in hemangioma endothelial cells are reduced by HIF-1α siRNA. Over-expression of HIF-1α increases VEGF levels and endothelial cell proliferation. Furthermore, both rapamycin and HIF-1α siRNA reduce proliferation of hemangioma endothelial cells. These data suggest that mTOR and HIF-1 contribute to hemangioma endothelial cell proliferation by stimulating an autocrine loop of VEGF signaling. Furthermore, mTOR and HIF-1 may be therapeutic targets for the treatment of hemangiomas.

  6. The Neuroprotective Effect of Rapamycin as a Modulator of the mTOR-NF-κB Axis during Retinal Inflammation.

    Directory of Open Access Journals (Sweden)

    Tomohiro Okamoto

    Full Text Available The determination of the molecular mechanism underlying retinal pathogenesis and visual dysfunction during innate inflammation, and the treatment effect of rapamycin thereon.The endotoxin-induced uveitis and retinitis mouse model was established by injecting lipopolysaccharide. The mice were subsequently treated with rapamycin, a mammalian target of rapamycin (mTOR inhibitor. The rhodopsin mRNA and protein expression level in the retina and the photoreceptor outer segment (OS length in immunohistochemical stainings were measured, and visual function was recorded by electroretinography. Inflammatory cytokines, their related molecules, mTOR, and LC3 levels were measured by real-time PCR and/or immunoblotting. Leukocyte adhesion during inflammation was analyzed using concanavalin A lectin.The post-transcriptional reduction in the visual pigment of rod photoreceptor cells, rhodopsin, OS shortening, and rod photoreceptor cell dysfunction during inflammation were suppressed by rapamycin. Activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB and induction of inflammatory cytokines, such as interleukin-6 (IL-6 and monocyte chemoattractant protein-1 (MCP-1, and the activation of the downstream signaling protein, signal transducer and activator of transcription 3 (STAT3, which reduces rhodopsin in the retina during inflammation, were attenuated by rapamycin. Increased leukocyte adhesion was also attenuated by rapamycin. Interestingly, although mTOR activation was observed after NF-κB activation, mTOR inhibition suppressed NF-κB activation at the early phase, indicating that the basal level of activated mTOR was sufficient to activate NF-κB in the retina. In addition, the inhibition of NF-κB suppressed mTOR activation, suggesting a positive feedback loop of mTOR and NF-κB during inflammation. The ratio of LC3II to LC3I, which reflects autophagy induction, was not changed by inflammation but was increased by rapamycin

  7. Systematic Review on Role of Mammalian Target of Rapamycin Inhibitors as an Alternative to Calcineurin Inhibitors in Renal Transplant: Challenges and Window to Excel.

    Science.gov (United States)

    Kumar, Jayant; Bridson, Julie M; Sharma, Ajay; Halawa, Ahmed

    2017-06-01

    This review focuses on the current limited evidence of graft function and graft survival in various immunosuppressive regimens involving mammalian target of rapamycin inhibitors with or without calcineurin inhibitors. We evaluated the current literature for describing the role of mammalian target of rapamycin inhibitors as an alternative to calcineurin inhibitors by searching the PubMed, EMBASE, Cochrane, Crossref, and Scopus databases using medical subject heading terms. Our detailed analyses of all relevant literature showed use of mammalian target of rapamycin inhibitor-based de novo regimens, early calcineurin inhibitor withdrawal with subsequent introduction of mammalian target of rapamycin inhibitor-based regimens, and late conversion from a calcineurin inhibitor-based regimen to mammalian target of rapamycin inhibitor-based regimens. Notably, early calcineurin inhibitor withdrawal with subsequent introduction of mammalian target of rapamycin inhibitor-based regimen seemed to be a more practical and realistic approach toward immunosuppressive treatment of renal transplant recipients. However, in view of the high rejection rate observed in these studies, it is advisable not to offer these regimens to patients with moderate to high immunologic risk. The present evidences suggest that treatment with mammalian target of rapamycin inhibitors allows early and substantial calcineurin inhibitor minimization. The mammalian target of rapamycin inhibitors everolimus and sirolimus are preferred due to their complementary mechanisms of action and favorable nephrotoxicity profile, which have opened the way for calcineurin inhibitor reduction/withdrawal in the early posttransplant period.

  8. Rapamycin-Induced Apoptosis in HGF-Stimulated Lens Epithelial Cells by AKT/mTOR, ERK and JAK2/STAT3 Pathways

    Directory of Open Access Journals (Sweden)

    Fang Tian

    2014-08-01

    Full Text Available Hepatocyte growth factor (HGF induced the proliferation of lens epithelial cells (LECs and may be a major cause of posterior capsule opacification (PCO, which is the most frequent postoperative complication of cataract surgery. To date, several agents that can block LECs proliferation have been studied, but none have been used in clinic. Recently, accumulating evidence has suggested rapamycin, the inhibitor of mTOR (mammalian target of Rapamycin, was associated with the induction of apoptosis in LECs. The purpose of our study was to investigate the potential effects of rapamycin on HGF-induced LECs and the underlying mechanisms by which rapamycin exerted its actions. Using cell proliferation, cell viability and flow cytometric apoptosis assays, we found that rapamycin potently not only suppressed proliferation but also induced the apoptosis of LECs in a dose-dependent manner under HGF administration. Further investigation of the underlying mechanism using siRNA transfection revealed that rapamycin could promote apoptosis of LECs via inhibiting HGF-induced phosphorylation of AKT/mTOR, ERK and JAK2/STAT3 signaling molecules. Moreover, the forced expression of AKT, ERK and STAT3 could induce a significant suppression of apoptosis in these cells after treatment of rapamycin. Together, these findings suggested that rapamycin-induced apoptosis in HGF-stimulated LECs is accompanied by inhibition of AKT/mTOR, ERK and JAK2/STAT3 pathways, which supports its use to inhibit PCO in preclinical studies and provides theoretical foundation for future possible practice.

  9. Rapamycin enhances lytic replication of Epstein-Barr virus in gastric carcinoma cells by increasing the transcriptional activities of immediate-early lytic promoters.

    Science.gov (United States)

    Wang, Man; Wu, Wei; Zhang, Yinfeng; Yao, Guoliang; Gu, Bianli

    2017-11-21

    Epstein-Barr virus (EBV), a human herpesvirus, is linked to both epithelial and lymphoid malignancies. Induction of EBV reactivation is a potential therapeutic strategy for EBV-associated tumors. In this study, we assessed the effects of rapamycin on EBV reactivation in gastric carcinoma cells. We found that rapamycin upregulated expression of EBV lytic proteins and increased the viral proliferation triggered by the EBV lytic inducer sodium butyrate. Reverse transcription-qPCR, luciferase activity assays, chromatin immunoprecipitation and western blotting were employed to explore the mechanism by which rapamycin promotes EBV reactivation. Our results showed that rapamycin treatment resulted in increased mRNA levels of EBV immediate-early genes. Rapamycin also enhanced the transcriptional activities of the EBV immediate-early lytic promoters Zp and Rp by strengthening Sp1 binding. Repression of the cellular ataxia telangiectasia-mutated/p53 pathway by siRNA-mediated knockdown of the ataxia telangiectasia-mutated gene significantly abrogated virus reactivation by rapamycin/sodium butyrate treatment, indicating that the ataxia telangiectasia-mutated/p53 pathway is involved in rapamycin-promoted EBV reactivation. Taken together, these findings demonstrate that rapamycin might have the potential to enhance the effectiveness of oncolytic viral therapies developed for EBV-associated malignancies. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Prospective pilot study on combined use of pulsed dye laser and 1% topical rapamycin for treatment of nonfacial cutaneous capillary malformation.

    Science.gov (United States)

    Doh, Eun Jin; Ohn, Jungyoon; Kim, Min Ji; Kim, Young Gull; Cho, Soyun

    2017-11-01

    The regeneration or revascularization of blood vessels after pulsed dye laser (PDL) treatment is one of the causes of treatment failures of cutaneous capillary malformations (CM). Recently, topical administration of rapamycin was introduced as a possible adjunctive therapeutic option to minimize postlaser revascularization in facial CM. We evaluated the effect of combined use of 1% topical rapamycin with PDL compared to PDL alone in cutaneous CM of trunk or extremities and tried to identify the optimal duration of topical rapamycin application. Three adjacent areas of cutaneous CM that had never been treated before were selected in each patient and underwent the following regimens: (A) PDL + vehicle for 8 weeks post-PDL; (B) PDL + topical rapamycin for 1-week post-PDL and (C) PDL + topical rapamycin for 8 weeks post-PDL. Each test site was treated by PDL for two sessions with 8 weeks interval. Only one of six patients showed clinical improvement with combined rapamycin treatment. Overall, there was no statistically significant difference in erythema and blanching rate among PDL alone and combined rapamycin regimens. One percent topical rapamycin does not seem to be effective as a treatment modality for cutaneous CM of trunk or extremities.

  11. Rapamycin reduces kidney volume and delays the loss of renal function in a patient with autosomal-dominant polycystic kidney disease

    Science.gov (United States)

    Peces, Ramón; Peces, Carlos; Pérez-Dueñas, Virginia; Cuesta-López, Emilio; Azorín, Sebastián; Selgas, Rafael

    2009-01-01

    This is the first report of a case of a reduction in kidney volume and preservation of renal function in a patient with autosomal-dominant polycystic kidney disease (ADPKD) receiving rapamycin. A 42-year-old man with ADPKD and a severe persistent bleeding from his solitary left kidney was successfully treated with tranexamic acid (TXA). He also received low-dose rapamycin for 8 months, and this was associated with a 23.5% reduction in kidney volume, improvement and stabilization of renal function, and normalization of haemoglobin levels. When treatment with rapamycin was interrupted, renal function deteriorated within an 8-month period and haemodialysis (HD) became necessary. Kidney volume increased at once, and life-threatening bleeding prompted a nephrectomy 4 months after the onset of HD. These data suggest that the reduction in kidney volume and preservation of renal function with rapamycin could be the result of the antiangiogenic, antiproliferative effects of rapamycin. PMID:25949309

  12. Rapamycin reduces kidney volume and delays the loss of renal function in a patient with autosomal-dominant polycystic kidney disease.

    Science.gov (United States)

    Peces, Ramón; Peces, Carlos; Pérez-Dueñas, Virginia; Cuesta-López, Emilio; Azorín, Sebastián; Selgas, Rafael

    2009-04-01

    This is the first report of a case of a reduction in kidney volume and preservation of renal function in a patient with autosomal-dominant polycystic kidney disease (ADPKD) receiving rapamycin. A 42-year-old man with ADPKD and a severe persistent bleeding from his solitary left kidney was successfully treated with tranexamic acid (TXA). He also received low-dose rapamycin for 8 months, and this was associated with a 23.5% reduction in kidney volume, improvement and stabilization of renal function, and normalization of haemoglobin levels. When treatment with rapamycin was interrupted, renal function deteriorated within an 8-month period and haemodialysis (HD) became necessary. Kidney volume increased at once, and life-threatening bleeding prompted a nephrectomy 4 months after the onset of HD. These data suggest that the reduction in kidney volume and preservation of renal function with rapamycin could be the result of the antiangiogenic, antiproliferative effects of rapamycin.

  13. Synthesis of (68)Ga-labeled NOTA-RGD-GE11 heterodimeric peptide for dual integrin and epidermal growth factor receptor-targeted tumor imaging.

    Science.gov (United States)

    Yu, Hung-Man; Chen, Jyun-Hong; Lin, Kun-Liang; Lin, Wuu-Jyh

    2015-06-15

    Radiolabeled Arg-Gly-Asp (RGD) peptide analogs have been extensively studied for αvβ3 integrin-targeted angiogenesis imaging. According to recently presented evidence, the dodecapeptide GE11 has high affinity to the epidermal growth factor receptor (EGFR), which is overexpressed in many types of cancer. Dual-receptor molecular imaging probes with two different heterodimeric peptides exhibit improved cancer targeting efficacy. In the present study, the design and synthesis of a new RGD-GE11 peptide heterodimer for dual αvβ3 integrin/EGFR-targeted cancer imaging are described. The RGD-GE11 heterodimer was linked with 6-aminohexanoic acid (6-Ahx) and cysteine and conjugated with 1,4,7-triazacyclononane-N,N',N″-triacetic acid (NOTA) to form NOTA-RGD-cys-6-Ahx-GE11. The monomeric peptides, NOTA-cys-6-Ahx-GE11 and c(RGDyK), were formed by a peptide synthesizer. The peptide heterodimer NOTA-RGD-GE11 was obtained by NOTA-cys-6-Ahx-GE11 and maleimidopropyl-c(RGDyK) conjugation with a thioether linkage. The NOTA peptide conjugate was labeled with freshly eluted (68)Ga and purified using reversed-phase high-performance liquid chromatography. The (68)Ga-NOTA-RGD-cys-6-Ahx-GE11 was successfully prepared, in this study, with a radiochemical yield of 85% and a radiochemical purity of >98%. These results warrant further investigation of this heterodimeric peptide's binding affinity to the receptors. Copyright © 2015 John Wiley & Sons, Ltd.

  14. MC4R dimerization in the paraventricular nucleus and GHSR/MC3R heterodimerization in the arcuate nucleus: is there relevance for body weight regulation?

    Science.gov (United States)

    Rediger, Anne; Piechowski, Carolin Leonie; Habegger, Kirk; Grüters, Annette; Krude, Heiko; Tschöp, Matthias H; Kleinau, Gunnar; Biebermann, Heike

    2012-01-01

    The worldwide obesity epidemic is increasing, yet at this time, no long-acting and specific pharmaceutical therapies are available. Peripheral hormonal signals communicate metabolic status to the hypothalamus by activating their corresponding receptors in the arcuate nucleus (ARC). In this brain region, a variety of G protein-coupled receptors (GPCRs) are expressed that are potentially involved in weight regulation, but so far, the detailed function of most hypothalamic GPCRs is only partially understood. An important and underappreciated feature of GPCRs is the capacity for regulation via di- and heterodimerization. Increasing evidence implicates that heterodimerization of GPCRs results in profound functional consequences. Recently, we could demonstrate that interaction of the melanocortin 3 receptor (MC3R) and the growth hormone secretagogue receptor (GHSR)-1a results in a modulation of function in both receptors. Although the physiological role of GPCR-GPCR interaction in the hypothalamus is yet to be elucidated, this concept promises new avenues for investigation and understanding of hypothalamic functions dependent on GPCR signaling. Since GPCRs are important targets for drugs to combat many diseases, identification of heterodimers may be a prerequisite for highly specific drugs. Therefore, a detailed understanding of the mechanisms and their involvement in weight regulation is necessary. Fundamental to this understanding is the interplay of GPCR-GPCR in the hypothalamic nuclei in energy metabolism. In this review, we summarize the current knowledge on melanocortin receptors and GHSR-1a in hypothalamic weight regulation, especially as they pertain to possible drug targets. Furthermore, we include available evidence for the participation and significance of GPCR dimerization. Copyright © 2012 S. Karger AG, Basel.

  15. Efficacy of Polyphenon E, Red Ginseng, and Rapamycin on Benzo(apyrene-Induced Lung Tumorigenesis in A/J Mice

    Directory of Open Access Journals (Sweden)

    Ying Yan

    2006-01-01

    Full Text Available The objective of this investigation was to determine the efficacy of several novel agents in preventing lung tumorigenesis in mice. We evaluated polyphenon E, red ginseng, and rapamycin in A/J mice treated with the tobacco-specific carcinogen benzo(apyrene for their ability to inhibit pulmonary adenoma formation and growth. We found that treatment with polyphenon E exhibited a significant reduction on both tumor multiplicity and tumor load (tumor multiplicity × tumor volume in a dose-dependent fashion. Polyphenon E (2% wt/wt in the diet reduced tumor multiplicity by 46% and tumor load by 94%. This result provided key evidence in support of a phase II clinical chemoprevention trial of lung cancer. Administration of red ginseng in drinking water decreased tumor multiplicity by 36% and tumor load by 70%. The mammalian target of rapamycin inhibitor rapamycin showed significant efficacy against lung tumor growth in the tumor progression protocol and reduced tumor load by 84%. The results of these investigations demonstrate that polyphenon E, red ginseng, and rapamycin significantly inhibit pulmonary adenoma formation and growth in A/J mice.

  16. Effects of rapamycin and curcumin treatment on the development of epilepsy after electrically induced status epilepticus in rats.

    NARCIS (Netherlands)

    Drion, C.M.; Borm, L.E.; Kooijman, L.; Aronica, E.; Wadman, W.J.; Hartog, A.F.; van Vliet, E.A.; Gorter, J.A.

    2016-01-01

    OBJECTIVE: Inhibition of the mammalian target of rapamycin (mTOR) pathway has been suggested as a possible antiepileptogenic strategy in temporal lobe epilepsy (TLE). Here we aim to elucidate whether mTOR inhibition has antiepileptogenic and/or antiseizure effects using different treatment

  17. Retinoic acid and rapamycin differentially affect and synergistically promote the ex vivo expansion of natural human T regulatory cells.

    Directory of Open Access Journals (Sweden)

    Tatiana N Golovina

    Full Text Available Natural T regulatory cells (Tregs are challenging to expand ex vivo, and this has severely hindered in vivo evaluation of their therapeutic potential. All trans retinoic acid (ATRA plays an important role in mediating immune homeostasis in vivo, and we investigated whether ATRA could be used to promote the ex vivo expansion of Tregs purified from adult human peripheral blood. We found that ATRA helped maintain FOXP3 expression during the expansion process, but this effect was transient and serum-dependent. Furthermore, natural Tregs treated with rapamycin, but not with ATRA, suppressed cytokine production in co-cultured effector T cells. This suppressive activity correlated with the ability of expanded Tregs to induce FOXP3 expression in non-Treg cell populations. Examination of CD45RA+ and CD45RA- Treg subsets revealed that ATRA failed to maintain suppressive activity in either population, but interestingly, Tregs expanded in the presence of both rapamycin and ATRA displayed more suppressive activity and had a more favorable epigenetic status of the FOXP3 gene than Tregs expanded in the presence of rapamycin only. We conclude that while the use of ATRA as a single agent to expand Tregs for human therapy is not warranted, its use in combination with rapamycin may have benefit.

  18. Neuroprotective effect of rapamycin on spinal cord injury via activation of the Wnt/β-catenin signaling pathway

    Directory of Open Access Journals (Sweden)

    Kai Gao

    2015-01-01

    Full Text Available The Wnt/β-catenin signaling pathway plays a crucial role in neural development, axonal guidance, neuropathic pain remission and neuronal survival. In this study, we initially examined the effect of rapamycin on the Wnt/β-catenin signaling pathway after spinal cord injury, by intraperitoneally injecting spinal cord injured rats with rapamycin over 2 days. Western blot analysis and immunofluorescence staining were used to detect the expression levels of β-catenin protein, ca-spase-3 protein and brain-derived neurotrophic factor protein, components of the Wnt/β-catenin signaling pathway. Rapamycin increased the levels of β-catenin and brain-derived neurotrophic factor in the injured spinal cord, improved the pathological morphology at the injury site, reduced the loss of motor neurons, and promoted motor functional recovery in rats after spinal cord injury. Our experimental findings suggest that the neuroprotective effect of rapamycin intervention is mediated through activation of the Wnt/β-catenin signaling pathway after spinal cord injury.

  19. Role of adenosine 5'-monophosphate-activated protein kinase subunits in skeletal muscle mammalian target of rapamycin signaling

    DEFF Research Database (Denmark)

    Deshmukh, Atul S.; Treebak, Jonas Thue; Long, Yun Chau

    2008-01-01

    AMP-activated protein kinase (AMPK) is an important energy-sensing protein in skeletal muscle. Mammalian target of rapamycin (mTOR) mediates translation initiation and protein synthesis through ribosomal S6 kinase 1 (S6K1) and eukaryotic initiation factor 4E-binding protein 1 (4E-BP1). AMPK activ...

  20. Rapamycin Protects from Type-I Peritoneal Membrane Failure Inhibiting the Angiogenesis, Lymphangiogenesis, and Endo-MT

    Directory of Open Access Journals (Sweden)

    Guadalupe Tirma González-Mateo

    2015-01-01

    Full Text Available Preservation of peritoneal membrane (PM is essential for long-term survival in peritoneal dialysis (PD. Continuous presence of PD fluids (PDF in the peritoneal cavity generates chronic inflammation and promotes changes of the PM, such as fibrosis, angiogenesis, and lymphangiogenesis. Mesothelial-to-mesenchymal transition (MMT and endothelial-to-mesenchymal transition (Endo-MT seem to play a central role in this pathogenesis. We speculated that Rapamycin, a potent immunosuppressor, could be beneficial by regulating blood and lymphatic vessels proliferation. We demonstrate that mice undergoing a combined PD and Rapamycin treatment (PDF + Rapa group presented a reduced PM thickness and lower number of submesothelial blood and lymphatic vessels, as well as decreased MMT and Endo-MT, comparing with their counterparts exposed to PD alone (PDF group. Peritoneal water transport in the PDF + Rapa group remained at control level, whereas PD effluent levels of VEGF, TGF-β, and TNF-α were lower than in the PDF group. Moreover, the treatment of mesothelial cells with Rapamycin in vitro significantly decreased VEGF synthesis and selectively inhibited the VEGF-C and VEGF-D release when compared with control cells. Thus, Rapamycin has a protective effect on PM in PD through an antifibrotic and antiproliferative effect on blood and lymphatic vessels. Moreover, it inhibits Endo-MT and, at least partially, MMT.

  1. mTOR Ser-2481 autophosphorylation monitors mTORC-specific catalytic activity and clarifies rapamycin mechanism of action.

    Science.gov (United States)

    Soliman, Ghada A; Acosta-Jaquez, Hugo A; Dunlop, Elaine A; Ekim, Bilgen; Maj, Nicole E; Tee, Andrew R; Fingar, Diane C

    2010-03-12

    The mammalian target of rapamycin (mTOR) Ser/Thr kinase signals in at least two multiprotein complexes distinguished by their different partners and sensitivities to rapamycin. Acute rapamycin inhibits signaling by mTOR complex 1 (mTORC1) but not mTOR complex 2 (mTORC2), which both promote cell growth, proliferation, and survival. Although mTORC2 regulation remains poorly defined, diverse cellular mitogens activate mTORC1 signaling in a manner that requires sufficient levels of amino acids and cellular energy. Before the identification of distinct mTOR complexes, mTOR was reported to autophosphorylate on Ser-2481 in vivo in a rapamycin- and amino acid-insensitive manner. These results suggested that modulation of mTOR intrinsic catalytic activity does not universally underlie mTOR regulation. Here we re-examine the regulation of mTOR Ser-2481 autophosphorylation (Ser(P)-2481) in vivo by studying mTORC-specific Ser(P)-2481 in mTORC1 and mTORC2, with a primary focus on mTORC1. In contrast to previous work, we find that acute rapamycin and amino acid withdrawal markedly attenuate mTORC1-associated mTOR Ser(P)-2481 in cycling cells. Although insulin stimulates both mTORC1- and mTORC2-associated mTOR Ser(P)-2481 in a phosphatidylinositol 3-kinase-dependent manner, rapamycin acutely inhibits insulin-stimulated mTOR Ser(P)-2481 in mTORC1 but not mTORC2. By interrogating diverse mTORC1 regulatory input, we find that without exception mTORC1-activating signals promote, whereas mTORC1-inhibitory signals decrease mTORC1-associated mTOR Ser(P)-2481. These data suggest that mTORC1- and likely mTORC2-associated mTOR Ser-2481 autophosphorylation directly monitors intrinsic mTORC-specific catalytic activity and reveal that rapamycin inhibits mTORC1 signaling in vivo by reducing mTORC1 catalytic activity.

  2. Synergism between the mTOR inhibitor rapamycin and FAK down-regulation in the treatment of acute lymphoblastic leukemia

    Directory of Open Access Journals (Sweden)

    Pei-Jie Shi

    2016-02-01

    Full Text Available Abstract Background Acute lymphoblastic leukemia (ALL is an aggressive malignant disorder of lymphoid progenitor cells in both children and adults. Although improvements in contemporary therapy and development of new treatment strategies have led to dramatic increases in the cure rate in children with ALL, the relapse rate remains high and the prognosis of relapsed childhood ALL is poor. Molecularly targeted therapies have emerged as the leading treatments in cancer therapy. Multi-cytotoxic drug regimens have achieved success, yet many studies addressing targeted therapies have focused on only one single agent. In this study, we attempted to investigate whether the effect of the mammalian target of rapamycin (mTOR inhibitor rapamycin is synergistic with the effect of focal adhesion kinase (FAK down-regulation in the treatment of ALL. Methods The effect of rapamycin combined with FAK down-regulation on cell proliferation, the cell cycle, and apoptosis was investigated in the human precursor B acute lymphoblastic leukemia cells REH and on survival time and leukemia progression in a non-obese diabetic/severe combined immunodeficiency (NOD/SCID mouse model. Results When combined with FAK down-regulation, rapamycin-induced suppression of cell proliferation, G0/G1 cell cycle arrest, and apoptosis were significantly enhanced. In addition, REH cell-injected NOD/SCID mice treated with rapamycin and a short-hairpin RNA (shRNA to down-regulate FAK had significantly longer survival times and slower leukemia progression compared with mice injected with REH-empty vector cells and treated with rapamycin. Moreover, the B-cell CLL/lymphoma-2 (BCL-2 gene family was shown to be involved in the enhancement, by combined treatment, of REH cell apoptosis. Conclusions FAK down-regulation enhanced the in vitro and in vivo inhibitory effects of rapamycin on REH cell growth, indicating that the simultaneous targeting of mTOR- and FAK-related pathways might offer a novel

  3. The Role of Mammalian Target of Rapamycin (mTOR) in Insulin Signaling.

    Science.gov (United States)

    Yoon, Mee-Sup

    2017-10-27

    The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that controls a wide spectrum of cellular processes, including cell growth, differentiation, and metabolism. mTOR forms two distinct multiprotein complexes known as mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2), which are characterized by the presence of raptor and rictor, respectively. mTOR controls insulin signaling by regulating several downstream components such as growth factor receptor-bound protein 10 (Grb10), insulin receptor substrate (IRS-1), F-box/WD repeat-containing protein 8 (Fbw8), and insulin like growth factor 1 receptor/insulin receptor (IGF-IR/IR). In addition, mTORC1 and mTORC2 regulate each other through a feedback loop to control cell growth. This review outlines the current understanding of mTOR regulation in insulin signaling in the context of whole body metabolism.

  4. The mammalian target of rapamycin at the crossroad between cognitive aging and Alzheimer’s disease

    Science.gov (United States)

    Talboom, Joshua S; Velazquez, Ramon; Oddo, Salvatore

    2015-01-01

    Age-dependent cognitive decline is a major debilitating event affecting even individuals who are otherwise healthy. Understanding the molecular basis underlying these changes may increase the healthspan of the elderly population. It may also reveal insights into the pathogenesis of numerous neurodegenerative disorders characterized by cognitive deficits, as aging is the major risk factor for most of these disorders. Alzheimer’s disease (AD), the most common neurodegenerative disorder, first manifests itself as deficits in encoding new memories. As AD progresses, these deficits spread to other cognitive domains that further debilitate the person before contributing to their demise. Suppression of the mammalian target of rapamycin (mTOR) increases healthspan and lifespan in several organisms. Numerous reports have linked alterations in mTOR signaling to age-dependent cognitive decline and the pathogenesis of AD. This review will discuss recent work highlighting the complex role of mTOR in cognitive aging and in the pathogenesis of AD. PMID:28721257

  5. The mammalian target of rapamycin at the crossroad between cognitive aging and Alzheimer's disease.

    Science.gov (United States)

    Talboom, Joshua S; Velazquez, Ramon; Oddo, Salvatore

    2015-01-01

    Age-dependent cognitive decline is a major debilitating event affecting even individuals who are otherwise healthy. Understanding the molecular basis underlying these changes may increase the healthspan of the elderly population. It may also reveal insights into the pathogenesis of numerous neurodegenerative disorders characterized by cognitive deficits, as aging is the major risk factor for most of these disorders. Alzheimer's disease (AD), the most common neurodegenerative disorder, first manifests itself as deficits in encoding new memories. As AD progresses, these deficits spread to other cognitive domains that further debilitate the person before contributing to their demise. Suppression of the mammalian target of rapamycin (mTOR) increases healthspan and lifespan in several organisms. Numerous reports have linked alterations in mTOR signaling to age-dependent cognitive decline and the pathogenesis of AD. This review will discuss recent work highlighting the complex role of mTOR in cognitive aging and in the pathogenesis of AD.

  6. Methylglyoxal activates the target of rapamycin complex 2-protein kinase C signaling pathway in Saccharomyces cerevisiae.

    Science.gov (United States)

    Nomura, Wataru; Inoue, Yoshiharu

    2015-04-01

    Methylglyoxal is a typical 2-oxoaldehyde derived from glycolysis. We show here that methylglyoxal activates the Pkc1-Mpk1 mitogen-activated protein (MAP) kinase cascade in a target of rapamycin complex 2 (TORC2)-dependent manner in the budding yeast Saccharomyces cerevisiae. We demonstrate that TORC2 phosphorylates Pkc1 at Thr(1125) and Ser(1143). Methylglyoxal enhanced the phosphorylation of Pkc1 at Ser(1143), which transmitted the signal to the downstream Mpk1 MAP kinase cascade. We found that the phosphorylation status of Pkc1(T1125) affected the phosphorylation of Pkc1 at Ser(1143), in addition to its protein levels. Methylglyoxal activated mammalian TORC2 signaling, which, in turn, phosphorylated Akt at Ser(473). Our results suggest that methylglyoxal is a conserved initiator of TORC2 signaling among eukaryotes. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  7. eIF4E-Overexpression imparts perillyl alcohol and rapamycin-mediated regulation of telomerase reverse transcriptase.

    Science.gov (United States)

    Sundin, Tabetha; Peffley, Dennis; Hentosh, Patricia

    2013-08-01

    Translation is mediated partly by regulation of free eukaryotic initiation factor 4E (eIF4E) levels through PI3K-Akt-mTOR signaling. Cancer cells treated with the plant-derived perillyl alcohol (POH) or the mechanistic target of rapamycin (mTOR) inhibitor rapamycin dephosphorylate eIF4E-binding protein (4E-BP1) and attenuate cap-dependent translation. We previously showed in cancer cell lines with elevated eIF4E that POH and rapamycin regulate telomerase activity through this pathway. Here, immortalized Chinese hamster ovary (CHO) control cells and CHO cells with forced eIF4E expression (rb4E) were used to elucidate eIF4E's role in telomerase regulation by POH and rapamycin. Despite 5-fold higher eIF4E amounts in rb4E, telomerase activity, telomerase reverse transcriptase (TERT) mRNA, and TERT protein were nearly equivalent in control and rb4E cells. In control cells, telomerase activity, TERT mRNA and protein levels were unaffected by either compound. In contrast, telomerase activity and TERT protein were both attenuated by either agent in rb4E cells, but without corresponding TERT mRNA decreases indicating a translational/post-translational process. S6K, Akt, and 4E-BP1 were modulated by mTOR mediators only in the presence of increased eIF4E. Thus, eIF4E-overexpression in rb4E cells enables inhibitory effects of POH and rapamycin on telomerase and TERT protein. Importantly, eIF4E-overexpression modifies cellular protein synthetic processes and gene regulation. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Rapamycin improves sociability in the BTBR T(+)Itpr3(tf)/J mouse model of autism spectrum disorders.

    Science.gov (United States)

    Burket, Jessica A; Benson, Andrew D; Tang, Amy H; Deutsch, Stephen I

    2014-01-01

    Overactivation of the mammalian target of rapamycin (mTOR) has been implicated in the pathogenesis of syndromic forms of autism spectrum disorders (ASDs), such as tuberous sclerosis complex, neurofibromatosis 1, and fragile X syndrome. Administration of mTORC1 (mTOR complex 1) inhibitors (e.g. rapamycin) in syndromic mouse models of ASDs improved behavior, cognition, and neuropathology. However, since only a minority of ASDs are due to the effects of single genes (∼10%), there is a need to explore inhibition of mTOR activity in mouse models that may be more relevant to the majority of nonsyndromic presentations, such as the genetically inbred BTBR T(+)Itpr3(tf)/J (BTBR) mouse model of ASDs. BTBR mice have social impairment and exhibit increased stereotypic behavior. In prior work, d-cycloserine, a partial glycineB site agonist that targets the N-methyl-d-aspartate (NMDA) receptor, was shown to improve sociability in both Balb/c and BTBR mouse models of ASDs. Importantly, NMDA receptor activation regulates mTOR signaling activity. The current study investigated the ability of rapamycin (10mg/kg, i.p.×four days), an mTORC1 inhibitor, to improve sociability and stereotypic behavior in BTBR mice. Using a standard paradigm to assess mouse social behavior, rapamycin improved several measures of sociability in the BTBR mouse, suggesting that mTOR overactivation represents a therapeutic target that mediates or contributes to impaired sociability in the BTBR mouse model of ASDs. Interestingly, there was no effect of rapamycin on stereotypic behaviors in this mouse model. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Rapamycin-binding FKBP25 associates with diverse proteins that form large intracellular entities

    Energy Technology Data Exchange (ETDEWEB)

    Galat, Andrzej, E-mail: galat@dsvidf.cea.fr; Thai, Robert

    2014-08-08

    Highlights: • The hFKBP25 interacts with diverse components of macromolecular entities. • We show that the endogenous human FKBP25 is bound to polyribosomes. • The endogenous hFKBP25 co-immunoprecipitated with nucleosomal proteins. • FKBP25 could induce conformational switch in macromolecular complexes. - Abstract: In this paper, we show some evidence that a member of the FK506-binding proteins, FKBP25 is associated to diverse components that are part of several different intracellular large-molecular mass entities. The FKBP25 is a high-affinity rapamycin-binding immunophilin, which has nuclear translocation signals present in its PPIase domain but it was detected both in the cytoplasm compartment and in the nuclear proteome. Analyses of antiFKBP25-immunoprecipitated proteins have revealed that the endogenous FKBP25 is associated to the core histones of the nucleosome, and with several proteins forming spliceosomal complexes and ribosomal subunits. Using polyclonal antiFKBP25 we have detected FKBP25 associated with polyribosomes. Added RNAs or 0.5 M NaCl release FKBP25 that was associated with the polyribosomes indicating that the immunophilin has an intrinsic capacity to form complexes with polyribonucleotides via its charged surface patches. Rapamycin or FK506 treatments of the polyribosomes isolated from porcine brain, HeLa and K568 cells caused a residual release of the endogenous FKBP25, which suggests that the immunophilin also binds to some proteins via its PPIase cavity. Our proteomics study indicates that the nuclear pool of the FKBP25 targets various nuclear proteins that are crucial for packaging of DNA, chromatin remodeling and pre-mRNA splicing whereas the cytosolic pool of this immunophilin is bound to some components of the ribosome.

  10. Impact of rapamycin on phenotype and tolerogenic function of dendritic cells via intravital optical imaging

    Science.gov (United States)

    Luo, Meijie; Zhang, Zhihong

    2014-03-01

    Rapamycin (RAPA) as a unique tolerance-promoting therapeutic drug is crucial to successful clinical organ transplantation. DC (Dendritic cells) play a critical role in antigen presentation to T cells to initiate immune responses involved in tissue rejection. Although the influence of RAPA on DC differentiation and maturation had been reported by some research groups, it is still controversial and unclear right now. In addition, it is also lack of study on investigating the role of DC in DTH reaction via intravital optical imaging. Herein, we investigated the effect of rapamycin on phenotype and function of bone marrow monocyte-derived DC both in vitro and in vivo. In vitro experiments by flow cytometry (FACS) showed that DC displayed decreased cell size and lower expression levels of surface molecule CD80 induced by RAPA; Furthermore, the phagocytic ability to OVA of DC was inhibited by RAPA started from 1 h to 2 h post co-incubation, but recovered after 4 h; In addition, the capacity of DC to activate naïve OT-II T cell proliferation was also inhibited at 3 day post co-incubation, but had no effect at 5 day, the data indicated this effect was reversible when removing the drug. More importantly, the DC-T interaction was monitored both in vitro and in intravital lymph node explant, and showed that RAPA-DC had a significant lower proportion of long-lived (>15min) contacts. Thus, RAPA displayed immunosuppressive to phenotypic and functional maturation of DC, and this phenomenon induced by RAPA may favorable in the clinical organ transplantation in future.

  11. Testosterone induces cardiomyocyte hypertrophy through mammalian target of rapamycin complex 1 pathway.

    Science.gov (United States)

    Altamirano, Francisco; Oyarce, César; Silva, Patricio; Toyos, Marcela; Wilson, Carlos; Lavandero, Sergio; Uhlén, Per; Estrada, Manuel

    2009-08-01

    Elevated testosterone concentrations induce cardiac hypertrophy but the molecular mechanisms are poorly understood. Anabolic properties of testosterone involve an increase in protein synthesis. The mammalian target of rapamycin complex 1 (mTORC1) pathway is a major regulator of cell growth, but the relationship between testosterone action and mTORC1 in cardiac cells remains unknown. Here, we investigated whether the hypertrophic effects of testosterone are mediated by mTORC1 signaling in cultured cardiomyocytes. Testosterone increases the phosphorylation of mTOR and its downstream targets 40S ribosomal protein S6 kinase 1 (S6K1; also known as RPS6KB1) and eukaryotic initiation factor 4E-binding protein 1 (4E-BP1). The S6K1 phosphorylation induced by testosterone was blocked by rapamycin and small interfering RNA to mTOR. Moreover, the hormone increased both extracellular-regulated kinase (ERK1/2) and protein kinase B (Akt) phosphorylation. ERK1/2 inhibitor PD98059 blocked the testosterone-induced S6K1 phosphorylation, whereas Akt inhibition (Akt-inhibitor-X) had no effect. Testosterone-induced ERK1/2 and S6K1 phosphorylation increases were blocked by either 1,2-bis(2-aminophenoxy)ethane-N,N,N,N-tetraacetic acid-acetoxymethylester or by inhibitors of inositol 1,4,5-trisphosphate (IP(3)) pathway: U-73122 and 2-aminoethyl diphenylborate. Finally, cardiomyocyte hypertrophy was evaluated by, the expression of beta-myosin heavy chain, alpha-skeletal actin, cell size, and amino acid incorporation. Testosterone increased all four parameters and the increase being blocked by mTOR inhibition. Our findings suggest that testosterone activates the mTORC1/S6K1 axis through IP(3)/Ca(2+) and MEK/ERK1/2 to induce cardiomyocyte hypertrophy.

  12. Loss of cardiac carnitine palmitoyltransferase 2 results in rapamycin-resistant, acetylation-independent hypertrophy.

    Science.gov (United States)

    Pereyra, Andrea S; Hasek, Like Y; Harris, Kate L; Berman, Alycia G; Damen, Frederick W; Goergen, Craig J; Ellis, Jessica M

    2017-11-10

    Cardiac hypertrophy is closely linked to impaired fatty acid oxidation, but the molecular basis of this link is unclear. Here, we investigated the loss of an obligate enzyme in mitochondrial long-chain fatty acid oxidation, carnitine palmitoyltransferase 2 (CPT2), on muscle and heart structure, function, and molecular signatures in a muscle- and heart-specific CPT2-deficient mouse (Cpt2 M-/- ) model. CPT2 loss in heart and muscle reduced complete oxidation of long-chain fatty acids by 87 and 69%, respectively, without altering body weight, energy expenditure, respiratory quotient, or adiposity. Cpt2M -/- mice developed cardiac hypertrophy and systolic dysfunction, evidenced by a 5-fold greater heart mass, 60-90% reduction in blood ejection fraction relative to control mice, and eventual lethality in the absence of cardiac fibrosis. The hypertrophy-inducing mammalian target of rapamycin complex 1 (mTORC1) pathway was activated in Cpt2M -/- hearts; however, daily rapamycin exposure failed to attenuate hypertrophy in Cpt2M -/- mice. Lysine acetylation was reduced by ∼50% in Cpt2M -/- hearts, but trichostatin A, a histone deacetylase inhibitor that improves cardiac remodeling, failed to attenuate Cpt2M -/- hypertrophy. Strikingly, a ketogenic diet increased lysine acetylation in Cpt2M -/- hearts 2.3-fold compared with littermate control mice fed a ketogenic diet, yet it did not improve cardiac hypertrophy. Together, these results suggest that a shift away from mitochondrial fatty acid oxidation initiates deleterious hypertrophic cardiac remodeling independent of fibrosis. The data also indicate that CPT2-deficient hearts are impervious to hypertrophy attenuators, that mitochondrial metabolism regulates cardiac acetylation, and that signals derived from alterations in mitochondrial metabolism are the key mediators of cardiac hypertrophic growth. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  13. Growth differentiation factor 15 stimulates rapamycin-sensitive ovarian cancer cell growth and invasion.

    Science.gov (United States)

    Griner, Samantha E; Joshi, Jayashree P; Nahta, Rita

    2013-01-01

    Identification of novel molecular markers and therapeutic targets may improve survival rates for patients with ovarian cancer. In the current study, immunohistochemical (IHC) analysis of two human ovarian tumor tissue arrays showed high staining for GDF15 in a majority of tissues. Exogenous stimulation of ovarian cancer cell lines with recombinant human GDF15 (rhGDF15) or stable over-expression of a GDF15 expression plasmid promoted anchorage-independent growth, increased invasion, and up-regulation of matrix metalloproteinases (MMPs) and vascular endothelial growth factor (VEGF). MMP inhibition suppressed GDF15-mediated invasion. In addition, IHC analysis of human ovarian tumor tissue arrays indicated that GDF15 expression correlated significantly with high MMP2 and MMP9 expression. Exogenous and endogenous GDF15 over-expression stimulated phosphorylation of p38, Erk1/2, and Akt. Pharmacologic inhibition of p38, MEK, or PI3K suppressed GDF15-stimulated growth. Further, proliferation, growth, and invasion of GDF15 stable clones were blocked by rapamycin. IHC analysis demonstrated significant correlation between GDF15 expression and phosphorylation of mTOR. Finally, knockdown of endogenous GDF15 or neutralization of secreted GDF15 suppressed invasion and growth of a GDF15-over-expressing ovarian cancer cell line. These data indicate that GDF15 over-expression, which occurred in a majority of human ovarian cancers, promoted rapamycin-sensitive invasion and growth of ovarian cancer cells. Inhibition of mTOR may be an effective therapeutic strategy for ovarian cancers that over-express GDF15. Future studies should examine GDF15 as a novel molecular target for blocking ovarian cancer progression. Copyright © 2012 Elsevier Inc. All rights reserved.

  14. A single rapamycin dose protects against late-stage experimental cerebral malaria via modulation of host immunity, endothelial activation and parasite sequestration.

    Science.gov (United States)

    Mejia, Pedro; Treviño-Villarreal, J Humberto; Reynolds, Justin S; De Niz, Mariana; Thompson, Andrew; Marti, Matthias; Mitchell, James R

    2017-11-09

    Maladaptive immune responses during cerebral malaria (CM) result in high mortality despite opportune anti-malarial chemotherapy. Rapamycin, an FDA-approved immunomodulator, protects against experimental cerebral malaria (ECM) in mice through effects on the host. However, the potential for reduced adaptive immunity with chronic use, combined with an incomplete understanding of mechanisms underlying protection, limit translational potential as an adjunctive therapy in CM. The results presented herein demonstrate that a single dose of rapamycin, provided as late as day 4 or 5 post-infection, protected mice from ECM neuropathology and death through modulation of distinct host responses to infection. Rapamycin prevented parasite cytoadherence in peripheral organs, including white adipose tissue, via reduction of CD36 expression. Rapamycin also altered the splenic immune response by reducing the number of activated T cells with migratory phenotype, while increasing local cytotoxic T cell activation. Finally, rapamycin reduced brain endothelial ICAM-1 expression concomitant with reduced brain pathology. Together, these changes potentially contributed to increased parasite elimination while reducing CD8 T cell migration to the brain. Rapamycin exerts pleotropic effects on host immunity, vascular activation and parasite sequestration that rescue mice from ECM, and thus support the potential clinical use of rapamycin as an adjunctive therapy in CM.

  15. Low-dose rapamycin reduces kidney volume angiomyolipomas and prevents the loss of renal function in a patient with tuberous sclerosis complex.

    Science.gov (United States)

    Peces, Ramón; Peces, Carlos; Cuesta-López, Emilio; Pérez-Dueñas, Virginia; Vega-Cabrera, Cristina; Azorín, Sebastián; Selgas, Rafael

    2010-11-01

    Tuberous sclerosis complex (TSC) is caused by constitutively activated mammalian target of rapamycin (mTOR) resulting in non-malignant tumours of several organs including renal angiomyolipomas (AMLs). AMLs may originate renal failure, hypertension and spontaneous life-threatening bleeding. Recent reports suggest a possible beneficial role of the mTOR inhibitor rapamycin for TSC. However, safety and efficiency of rapamycin in TSC patients as an anti-proliferative agent are still undefined. A 40-year-old man with sporadic TSC and a history of spontaneous bleeding from his left kidney AMLs received low-dose rapamycin for 12 months, and this was associated with a reduction in bilateral kidney AML volume, stabilization and even improvement of renal function. There was also a reduction of facial angiofibromas, improvement of blood pressure control and absence of AML bleeding over this time period. Brain lesion images remained stable, and no significant rapamycin-associated side effects were noted. To the best of our knowledge, this is the first report of a case of reduction in renal AML volume together with preservation of renal function in a patient with TSC receiving low-dose rapamycin. These data suggest that it could be the result of the anti-angiogenic, anti-fibrotic and anti-proliferative effects of rapamycin.

  16. Molecular insights into the stabilization of protein-protein interactions with small molecule: The FKBP12-rapamycin-FRB case study

    Science.gov (United States)

    Chaurasia, Shilpi; Pieraccini, Stefano; De Gonda, Riccardo; Conti, Simone; Sironi, Maurizio

    2013-11-01

    Targetting protein-protein interactions is a challenging task in drug discovery process. Despite the challenges, several studies provided evidences for the development of small molecules modulating protein-protein interactions. Here we consider a typical case of protein-protein interaction stabilization: the complex between FKBP12 and FRB with rapamycin. We have analyzed the stability of the complex and characterized its interactions at the atomic level by performing free energy calculations and computational alanine scanning. It is shown that rapamycin stabilizes the complex by acting as a bridge between the two proteins; and the complex is stable only in the presence of rapamycin.

  17. Imaging integrin αvβ 3 and NRP-1 positive gliomas with a novel fluorine-18 labeled RGD-ATWLPPR heterodimeric peptide probe.

    Science.gov (United States)

    Wu, Hua; Chen, Haojun; Pan, Dongfeng; Ma, Yufei; Liang, Sheng; Wan, Ying; Fang, Ya

    2014-12-01

    Radiolabeled Arg-Gly-Asp (RGD) and Ala-Thr-Trp-Leu-Pro-Pro-Arg (ATWLPPR) peptide analogs have received interests for their capability to serve as radiopharmaceuticals for imaging integrin αvβ3 and Neuropilin-1 (NRP-1) positive tumors, respectively. In this study, we developed a RGD-ATWLPPR heterodimeric peptide which contained both RGD and ATWLPPR motifs in one molecular probe. The aim of this study was to investigate the dual receptor-targeting property and tumor diagnostic value of RGD-ATWLPPR heterodimeric peptide labeled with fluorine-18 (F-18). A RGD-ATWLPPR heterodimer was synthesized from c(RGDyK) and ATWLPPR through a glutamate linker. The peptide was radiolabeled by reacting the [(18)F]fluoride-aluminum complex with the cyclic chelator, 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA). The receptor-binding characteristics and tumor-targeting efficacy of [(18)F]FAl-NOTA-RGD-ATWLPPR were tested in vitro and in vivo. RGD-ATWLPPR had affinity for both integrin αvβ3 and NRP-1 in vitro. [(18)F]FAl-NOTA-RGD-ATWLPPR displayed significantly higher tumor uptake than [(18)F]FAl-NOTA-RGD and [(18)F]FAl-NOTA-ATWLPPR, both in vitro and in vivo. The uptake of the F-18 labeled heterodimer by an U87MG tumor was inhibited only partially in the presence of an excess amount of unlabeled RGD or ATWLPPR but was blocked completely in the presence of both RGD and ATWLPPR. Compared with the monomeric RGD and ATWLPPR peptides, [(18)F]FAl-NOTA-RGD-ATWLPPR showed improved in vivo pharmacokinetics, resulting in a more preferable imaging quality. [(18)F]FAl-NOTA-RGD-ATWLPPR exhibited significantly improved receptor-targeting properties both in vitro and in vivo compared with the F-18 labeled RGD or ATWLPPR monomers. The improved targeting and localization exhibited by the RGD-ATWLPPR heterodimer provide a foundation for further investigations of its applicability in clinical tumor imaging.

  18. Beneficial metabolic effects of rapamycin are associated with enhanced regulatory cells in diet-induced obese mice.

    Science.gov (United States)

    Makki, Kassem; Taront, Solenne; Molendi-Coste, Olivier; Bouchaert, Emmanuel; Neve, Bernadette; Eury, Elodie; Lobbens, Stéphane; Labalette, Myriam; Duez, Hélène; Staels, Bart; Dombrowicz, David; Froguel, Philippe; Wolowczuk, Isabelle

    2014-01-01

    The "mechanistic target of rapamycin" (mTOR) is a central controller of growth, proliferation and/or motility of various cell-types ranging from adipocytes to immune cells, thereby linking metabolism and immunity. mTOR signaling is overactivated in obesity, promoting inflammation and insulin resistance. Therefore, great interest exists in the development of mTOR inhibitors as therapeutic drugs for obesity or diabetes. However, despite a plethora of studies characterizing the metabolic consequences of mTOR inhibition in rodent models, its impact on immune changes associated with the obese condition has never been questioned so far. To address this, we used a mouse model of high-fat diet (HFD)-fed mice with and without pharmacologic mTOR inhibition by rapamycin. Rapamycin was weekly administrated to HFD-fed C57BL/6 mice for 22 weeks. Metabolic effects were determined by glucose and insulin tolerance tests and by indirect calorimetry measures of energy expenditure. Inflammatory response and immune cell populations were characterized in blood, adipose tissue and liver. In parallel, the activities of both mTOR complexes (e. g. mTORC1 and mTORC2) were determined in adipose tissue, muscle and liver. We show that rapamycin-treated mice are leaner, have enhanced energy expenditure and are protected against insulin resistance. These beneficial metabolic effects of rapamycin were associated to significant changes of the inflammatory profiles of both adipose tissue and liver. Importantly, immune cells with regulatory functions such as regulatory T-cells (Tregs) and myeloid-derived suppressor cells (MDSCs) were increased in adipose tissue. These rapamycin-triggered metabolic and immune effects resulted from mTORC1 inhibition whilst mTORC2 activity was intact. Taken together, our results reinforce the notion that controlling immune regulatory cells in metabolic tissues is crucial to maintain a proper metabolic status and, more generally, comfort the need to search for novel

  19. Oral adverse events associated with tyrosine kinase and mammalian target of rapamycin inhibitors in renal cell carcinoma: a structured literature review

    NARCIS (Netherlands)

    Boers-Doets, Christine B.; Epstein, Joel B.; Raber-Durlacher, Judith E.; Ouwerkerk, Jan; Logan, Richard M.; Brakenhoff, Jan A.; Lacouture, Mario E.; Gelderblom, Hans

    2012-01-01

    Oral adverse events (OAEs) associated with multitargeted tyrosine kinase inhibitors (TKIs) and mammalian target of rapamycin inhibitors (mTORIs) are underestimated but frequent and novel presentations of mucosal manifestations. Because optimal antitumor activity requires maintaining the optimal

  20. Oral adverse events associated with tyrosine kinase and mammalian target of rapamycin inhibitors in renal cell carcinoma: a structured literature review

    NARCIS (Netherlands)

    Boers-Doets, C.B.; Epstein, J.B.; Raber-Durlacher, J.E.; Ouwerkerk, J.; Logan, R.M.; Brakenhoff, J.A.; Lacouture, M.E.; Gelderblom, H.

    2012-01-01

    Background. Oral adverse events (OAEs) associated with multitargeted tyrosine kinase inhibitors (TKIs) and mammalian target of rapamycin inhibitors (mTORIs) are underestimated but frequent and novel presentations of mucosal manifestations. Because optimal antitumor activity requires maintaining the

  1. Bursicon, the insect cuticle-hardening hormone, is a heterodimeric cystine knot protein that activates G protein-coupled receptor LGR2.

    Science.gov (United States)

    Luo, Ching-Wei; Dewey, Elizabeth M; Sudo, Satoko; Ewer, John; Hsu, Sheau Yu; Honegger, Hans-Willi; Hsueh, Aaron J W

    2005-02-22

    All arthropods periodically molt to replace their exoskeleton (cuticle). Immediately after shedding the old cuticle, the neurohormone bursicon causes the hardening and darkening of the new cuticle. Here we show that bursicon, to our knowledge the first heterodimeric cystine knot hormone found in insects, consists of two proteins encoded by the genes burs and pburs (partner of burs). The pburs/burs heterodimer from Drosophila melanogaster binds with high affinity and specificity to activate the G protein-coupled receptor DLGR2, leading to the stimulation of cAMP signaling in vitro and tanning in neck-ligated blowflies. Native bursicon from Periplaneta americana is also a heterodimer. In D. melanogaster the levels of pburs, burs, and DLGR2 transcripts are increased before ecdysis, consistent with their role in postecdysial cuticle changes. Immunohistochemical analyses in diverse insect species revealed the colocalization of pburs- and burs-immunoreactivity in some of the neurosecretory neurons that also express crustacean cardioactive peptide. Forty-three years after its initial description, the elucidation of the molecular identity of bursicon and the verification of its receptor allow for studies of bursicon actions in regulating cuticle tanning, wing expansion, and as yet unknown functions. Because bursicon subunit genes are homologous to the vertebrate bone morphogenetic protein antagonists, our findings also facilitate investigation on the function of these proteins during vertebrate development.

  2. Total Chemical Synthesis of a Heterodimeric Interchain Bis-Lactam-Linked Peptide: Application to an Analogue of Human Insulin-Like Peptide 3

    Directory of Open Access Journals (Sweden)

    John Karas

    2013-01-01

    Full Text Available Nonreducible cystine isosteres represent important peptide design elements in that they can maintain a near-native tertiary conformation of the peptide while simultaneously extending the in vitro and in vivo half-life of the biomolecule. Examples of these cystine mimics include dicarba, diselenide, thioether, triazole, and lactam bridges. Each has unique physicochemical properties that impact upon the resulting peptide conformation. Each also requires specific conditions for its formation via chemical peptide synthesis protocols. While the preparation of peptides containing two lactam bonds within a peptide is technically possible and reported by others, to date there has been no report of the chemical synthesis of a heterodimeric peptide linked by two lactam bonds. To examine the feasibility of such an assembly, judicious use of a complementary combination of amine and acid protecting groups together with nonfragment-based, total stepwise solid phase peptide synthesis led to the successful preparation of an analogue of the model peptide, insulin-like peptide 3 (INSL3, in which both of the interchain disulfide bonds were replaced with a lactam bond. An analogue containing a single disulfide-substituted interchain lactam bond was also prepared. Both INSL3 analogues retained significant cognate RXFP2 receptor binding affinity.

  3. Differential expression of maize chitinases in the presence or absence of Trichoderma harzianum strain T22 and indications of a novel exo- endo-heterodimeric chitinase activity

    Directory of Open Access Journals (Sweden)

    Harman Gary E

    2010-07-01

    Full Text Available Abstract Background The interaction of plants with endophytic symbiotic fungi in the genus Trichoderma alters the plant proteome and transcriptome and results in enhanced plant growth and resistance to diseases. In a previous study, we identified the numerous chitinolytic enzyme families and individual enzymes in maize which are implicated in plant disease resistance and other plant responses. Results We examined the differential expression of the entire suite of chitinolytic enzymes in maize plants in the presence and absence of T. harzianum. Expression of these enzymes revealed a band of chitinolytic enzyme activity that had greater mass than any known chitinase. This study reports the characterization of this large protein. It was found to be a heretofore undiscovered heterodimer between an exo- and an endo-enzyme, and the endo portion differed between plants colonized with T. harzianum and those grown in its absence and between shoots and roots. The heterodimeric enzymes from shoots in the presence and absence of T. harzianum were purified and characterized. The dimeric enzyme from Trichoderma-inoculated plants had higher specific activity and greater ability to inhibit fungal growth than those from control plants. The activity of specific chitinolytic enzymes was higher in plants grown from Trichoderma treated seeds than in control plants. Conclusions This is the first report of a dimer between endo- and exochitinase. The endochitinase component of the dimer changed post Trichoderma inoculation. The dimer originating from Trichoderma inoculated plants had a higher antifungal activity than the comparable enzyme from control plants.

  4. Heterodimerization of the transcription factors E2F-1 and DP-1 is required for binding to the adenovirus E4 (ORF6/7) protein

    DEFF Research Database (Denmark)

    Helin, K; Harlow, E

    1994-01-01

    Adenovirus infection leads to E1A-dependent activation of the transcription factor E2F. E2F has recently been identified in complexes with cellular proteins such as the retinoblastoma protein (pRB) and the two pRB family members p107 and p130. E1A dissociates E2F from these cellular proteins......, and another viral protein, E4 (ORF6/7), can bind to E2F. The binding of E4 to E2F induces the formation of a stable DNA-binding complex containing the two proteins, and stimulation of the adenovirus E2 early promoter can occur. Recent studies have shown that E2F is the combined activity of several proteins......, and we demonstrate here that heterodimerization of two of these proteins, E2F-1 and DP-1, is required for stable binding to E4. This complex is formed independently of DNA binding and requires the C-terminal 20 amino acids of E4. Furthermore, the binding is dependent on a region of E2F-1 between amino...

  5. Differential expression of maize chitinases in the presence or absence of Trichoderma harzianum strain T22 and indications of a novel exo- endo-heterodimeric chitinase activity.

    Science.gov (United States)

    Shoresh, Michal; Harman, Gary E

    2010-07-01

    The interaction of plants with endophytic symbiotic fungi in the genus Trichoderma alters the plant proteome and transcriptome and results in enhanced plant growth and resistance to diseases. In a previous study, we identified the numerous chitinolytic enzyme families and individual enzymes in maize which are implicated in plant disease resistance and other plant responses. We examined the differential expression of the entire suite of chitinolytic enzymes in maize plants in the presence and absence of T. harzianum. Expression of these enzymes revealed a band of chitinolytic enzyme activity that had greater mass than any known chitinase. This study reports the characterization of this large protein. It was found to be a heretofore undiscovered heterodimer between an exo- and an endo-enzyme, and the endo portion differed between plants colonized with T. harzianum and those grown in its absence and between shoots and roots. The heterodimeric enzymes from shoots in the presence and absence of T. harzianum were purified and characterized. The dimeric enzyme from Trichoderma-inoculated plants had higher specific activity and greater ability to inhibit fungal growth than those from control plants. The activity of specific chitinolytic enzymes was higher in plants grown from Trichoderma treated seeds than in control plants. This is the first report of a dimer between endo- and exochitinase. The endochitinase component of the dimer changed post Trichoderma inoculation. The dimer originating from Trichoderma inoculated plants had a higher antifungal activity than the comparable enzyme from control plants.

  6. Rapamycin-insensitive up-regulation of adipocyte phospholipase A2 in tuberous sclerosis and lymphangioleiomyomatosis.

    Directory of Open Access Journals (Sweden)

    Chenggang Li

    Full Text Available Tuberous sclerosis syndrome (TSC is an autosomal dominant tumor suppressor gene syndrome affecting multiple organs, including renal angiomyolipomas and pulmonary lymphangioleiomyomatosis (LAM. LAM is a female-predominant interstitial lung disease characterized by the progressive cyst formation and respiratory failure, which is also seen in sporadic patients without TSC. Mutations in TSC1 or TSC2 cause TSC, result in hyperactivation of mammalian target of rapamycin (mTOR, and are also seen in LAM cells in sporadic LAM. We recently reported that prostaglandin biosynthesis and cyclooxygenase-2 were deregulated in TSC and LAM. Phospholipase A2 (PLA2 is the rate-limiting enzyme that catalyzes the conversion of plasma membrane phospholipids into prostaglandins. In this study, we identified upregulation of adipocyte AdPLA2 (PLA2G16 in LAM nodule cells using publicly available expression data. We showed that the levels of AdPLA2 transcript and protein were higher in LAM lungs compared with control lungs. We then showed that TSC2 negatively regulates the expression of AdPLA2, and loss of TSC2 is associated with elevated production of prostaglandin E2 (PGE2 and prostacyclin (PGI2 in cell culture models. Mouse model studies also showed increased expression of AdPLA2 in xenograft tumors, estrogen-induced lung metastatic lesions of Tsc2 null leiomyoma-derived cells, and spontaneous renal cystadenomas from Tsc2+/- mice. Importantly, rapamycin treatment did not affect the expression of AdPLA2 and the production of PGE2 by TSC2-deficient mouse embryonic fibroblast (Tsc2-/-MEFs, rat uterine leiomyoma-derived ELT3 cells, and LAM patient-associated renal angiomyolipoma-derived "mesenchymal" cells. Furthermore, methyl arachidonyl fluorophosphate (MAFP, a potent irreversible PLA2 inhibitor, selectively suppressed the growth and induced apoptosis of TSC2-deficient LAM patient-derived cells relative to TSC2-addback cells. Our findings suggest that AdPLA2 plays an

  7. Effect of rapamycin on spleen size in longstanding renal transplant recipients.

    Science.gov (United States)

    Araújo, N C; Sampaio Gonçalves de Lucena, S B; da Silveira Rioja, S

    2014-06-01

    Based on evidence available in the literature, rapamycin, a mammalian target of rapamycin (mTOR) inhibitor, but not calcineurin inhibitors (CNIs), has been shown to decrease spleen size. Small spleen, in some instances, is associated with hyposplenism, a condition recently reported in patients with longstanding renal transplant. Accordingly, the effect of immunosuppressive drugs on spleen size was evaluated. Renal transplant recipients (35 taking mTOR and 68 CNI) were included, in whom a standardized investigation of the kidney allograft and spleen with the use of color Doppler ultrasound was performed and a peripheral smear were reviewed for the presence of Howell-Jolly bodies (HJBs). We enrolled 103 patients (64 men; 66 from a deceased donor). The mean age was 47.7 years (range, 23.0-74.0 y). Mean transplant duration was 1,899 days (range, 181-6,883 d). According to the presence of HJBs, the prevalence of hyposplenism was 47.6% for the entire cohort. The differences between the mTOR and CNI groups regarding sex and the presence of HJBs were not statistically significant (P > .05). Age, creatinine, hemoglobin, leukocytes, platelets, and Doppler parameters in spleen and kidney were similar in both groups (P > .05). mTOR patients had a decreased spleen length size (90.09 ± 13.02 mm vs 111.95 ± 18.66 mm; P < .001), a longer transplant duration (3,576 ± 1,594 d vs 1,036 ± 1,369 d; P < .001) and higher serum cholesterol (227.50 ± 38.75 mg/dL vs 182.67 ± 37.74 mg/dL; P < .001) and triglycerides (194.23 ± 79.88 mg/dL vs 148.70 ± 55.54 mg/dL; P = .003) levels compared with the CNI group. A multivariate analysis showed mTOR inhibitor to be the most important predictor of spleen size. In both the mTOR and CNI groups, the comparison between the subgroups of present and absent HJBs did not show any difference. The findings of this study suggest that small spleens in transplant recipients may be linked to treatment with an mTOR inhibitor, although this apparently does

  8. Current Models of Mammalian Target of Rapamycin Complex 1 (mTORC1) Activation by Growth Factors and Amino Acids

    Science.gov (United States)

    Zheng, Xu; Liang, Yan; He, Qiburi; Yao, Ruiyuan; Bao, Wenlei; Bao, Lili; Wang, Yanfeng; Wang, Zhigang

    2014-01-01

    Mammalian target of rapamycin (mTOR), which is now referred to as mechanistic target of rapamycin, integrates many signals, including those from growth factors, energy status, stress, and amino acids, to regulate cell growth and proliferation, protein synthesis, protein degradation, and other physiological and biochemical processes. The mTOR-Rheb-TSC-TBC complex co-localizes to the lysosome and the phosphorylation of TSC-TBC effects the dissociation of the complex from the lysosome and activates Rheb. GTP-bound Rheb potentiates the catalytic activity of mTORC1. Under conditions with growth factors and amino acids, v-ATPase, Ragulator, Rag GTPase, Rheb, hVps34, PLD1, and PA have important but disparate effects on mTORC1 activation. In this review, we introduce five models of mTORC1 activation by growth factors and amino acids to provide a comprehensive theoretical foundation for future research. PMID:25402640

  9. Current Models of Mammalian Target of Rapamycin Complex 1 (mTORC1 Activation by Growth Factors and Amino Acids

    Directory of Open Access Journals (Sweden)

    Xu Zheng

    2014-11-01

    Full Text Available Mammalian target of rapamycin (mTOR, which is now referred to as mechanistic target of rapamycin, integrates many signals, including those from growth factors, energy status, stress, and amino acids, to regulate cell growth and proliferation, protein synthesis, protein degradation, and other physiological and biochemical processes. The mTOR-Rheb-TSC-TBC complex co-localizes to the lysosome and the phosphorylation of TSC-TBC effects the dissociation of the complex from the lysosome and activates Rheb. GTP-bound Rheb potentiates the catalytic activity of mTORC1. Under conditions with growth factors and amino acids, v-ATPase, Ragulator, Rag GTPase, Rheb, hVps34, PLD1, and PA have important but disparate effects on mTORC1 activation. In this review, we introduce five models of mTORC1 activation by growth factors and amino acids to provide a comprehensive theoretical foundation for future research.

  10. Giant bilateral renal angiomyolipomas and lymphangioleiomyomatosis presenting after two successive pregnancies successfully treated with surgery and rapamycin.

    Science.gov (United States)

    Peces, Ramón; Cuesta-López, Emilio; Peces, Carlos; Selgas, Rafael

    2011-01-01

    We report the case of a 25-year-old woman who presented with abdominal and flank pain with two successive pregnancies and was diagnosed of giant bilateral renal AMLs and pulmonary LAM associated with TSC in the post-partum of her second pregnancy. This case illustrates that in women with TSC rapid growth from renal AMLs and development of LAM may occur with successive pregnancies. It also stresses the potential for preservation of renal function despite successive bilateral renal surgery of giant AMLs. Moreover, the treatment with a low-dose rapamycin may be an option for LAM treatment. Finally, a low-dose rapamycin may be considered as an adjuvant treatment together to kidney-sparing conservative surgery for renal AMLs.

  11. Giant Bilateral Renal Angiomyolipomas and Lymphangioleiomyomatosis Presenting after Two Successive Pregnancies Successfully Treated with Surgery and Rapamycin

    Directory of Open Access Journals (Sweden)

    Ramón Peces

    2011-01-01

    Full Text Available We report the case of a 25-year-old woman who presented with abdominal and flank pain with two successive pregnancies and was diagnosed of giant bilateral renal AMLs and pulmonary LAM associated with TSC in the post-partum of her second pregnancy. This case illustrates that in women with TSC rapid growth from renal AMLs and development of LAM may occur with successive pregnancies. It also stresses the potential for preservation of renal function despite successive bilateral renal surgery of giant AMLs. Moreover, the treatment with a low-dose rapamycin may be an option for LAM treatment. Finally, a low-dose rapamycin may be considered as an adjuvant treatment together to kidney-sparing conservative surgery for renal AMLs.

  12. Rapamycin restores BDNF-LTP and the persistence of long-term memory in a model of Down's syndrome.

    Science.gov (United States)

    Andrade-Talavera, Yuniesky; Benito, Itziar; Casañas, Juan José; Rodríguez-Moreno, Antonio; Montesinos, María Luz

    2015-10-01

    Down's syndrome (DS) is the most prevalent genetic intellectual disability. Memory deficits significantly contribute to the cognitive dysfunction in DS. Previously, we discovered that mTOR-dependent local translation, a pivotal process for some forms of synaptic plasticity, is deregulated in a DS mouse model. Here, we report that these mice exhibit deficits in both synaptic plasticity (i.e., BDNF-long term potentiation) and the persistence of spatial long-term memory. Interestingly, these deficits were fully reversible using rapamycin, a Food and Drug Administration-approved specific mTOR inhibitor; therefore, rapamycin may be a novel pharmacotherapy to improve cognition in DS. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Topical rapamycin as a treatment for fibrofolliculomas in Birt-Hogg-Dubé syndrome: a double-blind placebo-controlled randomized split-face trial.

    Directory of Open Access Journals (Sweden)

    Lieke M C Gijezen

    Full Text Available Birt-Hogg-Dubé syndrome (BHD is a rare autosomal dominant disorder characterised by the occurrence of benign, mostly facial, skin tumours called fibrofolliculomas, multiple lung cysts, spontaneous pneumothorax and an increased renal cancer risk. Current treatments for fibrofolliculomas have high rates of recurrence and carry a risk of complications. It would be desirable to have a treatment that could prevent fibrofolliculomas from growing. Animal models of BHD have previously shown deregulation of mammalian target of rapamycin (mTOR. Topical use of the mTOR inhibitor rapamycin is an effective treatment for the skin tumours (angiofibromas in tuberous sclerosis complex, which is also characterised by mTOR deregulation. In this study we aimed to determine if topical rapamycin is also an effective treatment for fibrofolliculomas in BHD.We performed a double blinded, randomised, facial left-right controlled trial of topical rapamycin 0.1% versus placebo in 19 BHD patients. Trial duration was 6 months. The primary outcome was cosmetic improvement as measured by doctors and patients. Changes in fibrofolliculoma number and size were also measured, as was occurrence of side effects.No change in cosmetic status of fibrofolliculomas was reported in the majority of cases for the rapamycin treated (79% by doctors, 53% by patients as well as the placebo treated facial sides (both 74%. No significant differences between rapamycin and placebo treated facial halves were observed (p = 1.000 for doctors opinion, p = 0.344 for patients opinion. No significant difference in fibrofolliculoma number or change in size of the fibrofolliculomas was seen after 6 months. Side effects occurred more often after rapamycin treatment (68% of patients than after placebo (58% of patients; p = 0.625. A burning sensation, erythema, itching and dryness were most frequently reported.This study provides no evidence that treatment of fibrofolliculomas with topical

  14. Hypertrophied myocardium is vulnerable to ischemia reperfusion injury and refractory to rapamycin-induced protection due to increased oxidative/nitrative stress.

    Science.gov (United States)

    Ma, Lei-Lei; Yin, Pei-Pei; Li, Yang; Kong, Fei-Juan; Guo, Jun-Jie; Shi, Hong-Tao; Zhu, Jian-Bin; Zou, Yun-Zeng; Ge, Jun-Bo

    2017-11-24

    Left ventricular hypertrophy (LVH) is causally related to increased morbidity and mortality following acute myocardial infarction (AMI) via still unknown mechanisms. Although rapamycin exerts cardioprotective effects against myocardial ischemia/reperfusion (MI/R) injury in normal animals, whether rapamycin-elicited cardioprotection are altered in the presence of LVH has yet to be determined. Pressure overload-induced cardiac hypertrophied mice and sham-operated controls were exposed to AMI by coronary artery ligation, and treated with vehicle or rapamycin  10 min before reperfusion. Rapamycin produced marked cardioprotection in normal control mice, whereas pressure overload-induced cardiac hypertrophied mice manifested enhanced myocardial injury, and was refractory to rapamycin-elicited cardioprotection evidenced by augmented infarct size, aggravated cardiomyocytes apoptosis, and worsening cardiac function. Rapamycin alleviated MI/R injury via ERK-dependent antioxidative pathways in normal mice, whereas cardiac hypertrophied mice manifested markedly exacerbated oxidative/nitrative stress after MI/R evidenced by the increased iNOS/gp91phox expression, superoxide production, total NO metabolites and nitrotyrosine content. Moreover, scavenging superoxide or peroxynitrite by selective gp91phox assembly inhibitor gp91ds-tat or ONOO- scavenger EUK134 markedly ameliorated MI/R injury, as shown by reduced myocardial oxidative/nitrative stress, alleviated myocardial infarction, hindered cardiomyocytes apoptosis, and improved cardiac function in aortic-banded mice. However, no additional cardioprotective effects was achieved when we combined rapamycin and gp91ds-tat or EUK134 in ischemic reperfused hearts with or without LVH. These results suggest that cardiac hypertrophy attenuated rapamycin-induced cardioprotection by increasing oxidative/nitrative stress and scavenging superoxide/peroxynitrite protects the hypertrophied heart from MI/R. ©2017 The Author(s).

  15. Rapamycin inhibits ox-LDL-induced inflammation in human endothelial cells in vitro by inhibiting the mTORC2/PKC/c-Fos pathway.

    Science.gov (United States)

    Sun, Juan-Juan; Yin, Xiao-Wei; Liu, Hui-Hui; Du, Wen-Xiu; Shi, Lu-Yao; Huang, Ya-Bo; Wang, Fen; Liu, Chun-Feng; Cao, Yong-Jun; Zhang, Yan-Lin

    2017-10-26

    Rapamycin and its derivative possess anti-atherosclerosis activity, but its effects on adhesion molecule expression and macrophage adhesion to endothelial cells during atherosclerosis remain unclear. In this study we explored the effects of rapamycin on ox-LDL-induced adhesion molecule expression and macrophage adhesion to endothelial cells in vitro and the underlying mechanisms. Ox-LDL (6-48 μg/mL) dose-dependently increased the protein levels of two adhesion molecules, intercellular adhesion molecule-1 (ICAM-1) and E-selectin, in human umbilical vein endothelial cells (HUVECs), whereas pretreatment with rapamycin (1-10 μmol/L) dose-dependently inhibited ox-LDL-induced increase in the adhesion molecule expression and macrophage adhesion to endothelial cells. Knockdown of mTOR or rictor, rather than raptor, mimicked the effects of rapamycin. Ox-LDL (100 μg/mL) time-dependently increased PKC phosphorylation in HUVECs, which was abolished by rapamycin or rictor siRNA. Pretreatment with PKC inhibitor staurospo¬rine significantly reduced ox-LDL-stimulated adhesion molecule expression and macrophage adhesion to endothelial cells, whereas pretreatment with PKC activator PMA/TPA attenuated the inhibitory effect of rapamycin on adhesion molecule expression. Ox-LDL (100 μg/mL) time-dependently increased c-Fos levels in HUVECs, and pretreatment with rapamycin or rictor siRNA significantly decreased expression of c-Fos. Knockdown of c-Fos antagonized ox-LDL-induced adhesion molecule expression and macrophage adhesion to endothelial cells. Our results demonstrate that rapamycin reduces ox-LDL-stimulated adhesion molecule expression and macrophage adhesion to endothelial cells by inhibiting mTORC2, but not mTORC1, and mTORC2 acts through the PKC/c-Fos signaling pathway.

  16. Whey Protein Concentrate Renders MDA-MB-231 Cells Sensitive to Rapamycin by Altering Cellular Redox State and Activating GSK3β/mTOR Signaling.

    Science.gov (United States)

    Cheng, Shih-Hsuan; Tseng, Yang-Ming; Wu, Szu-Hsien; Tsai, Shih-Meng; Tsai, Li-Yu

    2017-11-21

    Whey protein concentrate (WPC) is an amino acid-rich supplement that has been shown to increase cellular antioxidant capacity. Mammalian target of rapamycin (mTOR) is a crucial regulator of signaling in mammalian cells, and serves as a therapeutic target for triple-negative breast cancer (TNBC). This study was designed to investigate the effect of combining WPC with rapamycin on MDA-MB-231 human breast cancer cells. These cells were found to be insensitive to rapamycin and exhibited higher glutathione (GSH) and reactive oxygen species levels than non-tumorigenic MCF-10A cells. However, for MDA-MB-231 cells, the half maximal inhibitory concentration of rapamycin was lower when this drug was administered in combination with WPC than when used alone. Furthermore, combining WPC with rapamycin depleted GSH levels and reduced Nrf2 nuclear accumulation. In addition, WPC activated GSK3β/mTOR signaling, and GSK3β appeared to be involved in the WPC-mediated Nrf2 reduction and mTOR activation. In conclusion, WPC induced rapamycin sensitivity in MDA-MB-231 cells by altering their redox state and activating GSK3β/mTOR signaling. These results not only suggest a novel therapeutic approach for breast cancer treatment, but also provide insight into the critical pathways affecting the resistance to mTOR inhibition observed in a subgroup of TNBC patients.

  17. Inhibition of mTOR by Rapamycin Results in Auditory Hair Cell Damage and Decreased Spiral Ganglion Neuron Outgrowth and Neurite Formation In Vitro

    Directory of Open Access Journals (Sweden)

    Katharina Leitmeyer

    2015-01-01

    Full Text Available Rapamycin is an antifungal agent with immunosuppressive properties. Rapamycin inhibits the mammalian target of rapamycin (mTOR by blocking the mTOR complex 1 (mTORC1. mTOR is an atypical serine/threonine protein kinase, which controls cell growth, cell proliferation, and cell metabolism. However, less is known about the mTOR pathway in the inner ear. First, we evaluated whether or not the two mTOR complexes (mTORC1 and mTORC2, resp. are present in the mammalian cochlea. Next, tissue explants of 5-day-old rats were treated with increasing concentrations of rapamycin to explore the effects of rapamycin on auditory hair cells and spiral ganglion neurons. Auditory hair cell survival, spiral ganglion neuron number, length of neurites, and neuronal survival were analyzed in vitro. Our data indicates that both mTOR complexes are expressed in the mammalian cochlea. We observed that inhibition of mTOR by rapamycin results in a dose dependent damage of auditory hair cells. Moreover, spiral ganglion neurite number and length of neurites were significantly decreased in all concentrations used compared to control in a dose dependent manner. Our data indicate that the mTOR may play a role in the survival of hair cells and modulates spiral ganglion neuronal outgrowth and neurite formation.

  18. Mycophenolate Mofetil and Rapamycin Induce Apoptosis in the Human Monocytic U937 Cell Line Through Two Different Pathways.

    Science.gov (United States)

    Nowak, Maxime; Tardivel, Sylviane; Nguyen-Khoa, Thao; Abreu, Sonia; Allaoui, Fatima; Fournier, Natalie; Chaminade, Pierre; Paul, Jean-Louis; Lacour, Bernard

    2017-10-01

    Transplant vasculopathy may be considered as an accelerated form of atherosclerosis resulting in chronic rejection of vascularized allografts. After organ transplantation, a diffuse intimal thickening is observed, leading to the development of an atherosclerosis plaque due to a significant monocyte infiltration. This results from a chronic inflammatory process induced by the immune response. In this study, we investigated the impact of two immunosuppressive drugs used in therapy initiated after organ transplantation, mycophenolate mofetil, and rapamycin, on the apoptotic response of monocytes induced or not by oxidized LDL. Here we show the pro-apoptotic effect of these two drugs through two distinct signaling pathways and we highlight a synergistic effect of rapamycin on apoptosis induced by oxidized LDL. In conclusion, since immunosuppressive therapy using mycophenolate mofetil or rapamycin can increase the cell death in a monocyte cell line, this treatment could exert similar effects on human monocytes in transplant patients, and thus, prevent transplant vasculopathy, atherosclerosis development, and chronic allograft rejection. J. Cell. Biochem. 118: 3480-3487, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  19. Rictor/mammalian target of rapamycin complex 2 promotes macrophage activation and kidney fibrosis.

    Science.gov (United States)

    Ren, Jiafa; Li, Jianzhong; Feng, Ye; Shu, Bingyan; Gui, Yuan; Wei, Wei; He, Weichun; Yang, Junwei; Dai, Chunsun

    2017-08-01

    Mammalian target of rapamycin (mTOR) signalling controls many essential cellular functions. However, the role of Rictor/mTOR complex 2 (mTORC2) in regulating macrophage activation and kidney fibrosis remains largely unknown. We report here that Rictor/mTORC2 was activated in macrophages from the fibrotic kidneys of mice. Ablation of Rictor in macrophages reduced kidney fibrosis, inflammatory cell accumulation, macrophage proliferation and polarization after unilateral ureter obstruction or ischaemia/reperfusion injury. In bone marrow-derived macrophages (BMMs), deletion of Rictor or blockade of protein kinase Cα inhibited cell migration. Additionally, deletion of Rictor or blockade of Akt abolished interleukin-4-stimulated or transforming growth factor (TGF)-β1-stimulated macrophage M2 polarization. Furthermore, deletion of Rictor downregulated TGF-β1-stimulated upregulation of multiple profibrotic cytokines, including platelet-derived growth factor, vascular endothelial growth factor and connective tissue growth factor, in BMMs. Conditioned medium from TGF-β1-pretreated Rictor-/- macrophages stimulated fibroblast activation less efficiently than that from TGF-β1-pretreated Rictor+/+ macrophages. These results demonstrate that Rictor/mTORC2 signalling can promote macrophage activation and kidney fibrosis. Targeting this signalling pathway in macrophages may shine light on ways to protect against kidney fibrosis in patients with chronic kidney diseases. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

  20. Mammalian target of rapamycin inhibition in polycystic kidney disease: From bench to bedside

    Directory of Open Access Journals (Sweden)

    Hyun-Jung Kim

    2012-09-01

    Full Text Available Autosomal dominant polycystic kidney disease (ADPKD is the most common life-threatening hereditary disease in the USA resulting in chronic kidney disease and the need for dialysis and transplantation. Approximately 85% of cases of ADPKD are caused by a mutation in the Pkd1 gene that encodes polycystin-1, a large membrane receptor. The Pkd1 gene mutation results in abnormal proliferation in tubular epithelial cells, which plays a crucial role in cyst development and/or growth in PKD. Activation of the proliferative mammalian target of rapamycin (mTOR signaling pathway has been demonstrated in polycystic kidneys from rodents and humans. mTOR inhibition with sirolimus or everolimus decreases cysts in most animal models of PKD including Pkd1 and Pkd2 gene deficient orthologous models of human disease. On the basis of animal studies, human studies were undertaken. Two large randomized clinical trials published in the New England Journal of Medicine of everolimus or sirolimus in ADPKD patients were very unimpressive and associated with a high side-effect profile. Possible reasons for the unimpressive nature of the human studies include their short duration, the high drop-out rate, suboptimal dosing, lack of randomization of “fast” and “slow progressors” and the lack of correlation between kidney size and kidney function in ADPKD. The future of mTOR inhibition in ADPKD is discussed.

  1. Bifunctional Elastin-like Polypeptide Nanoparticles Bind Rapamycin and Integrins and Suppress Tumor Growth in Vivo.

    Science.gov (United States)

    Dhandhukia, Jugal P; Shi, Pu; Peddi, Santosh; Li, Zhe; Aluri, Suhaas; Ju, Yaping; Brill, Dab; Wang, Wan; Janib, Siti M; Lin, Yi-An; Liu, Shuanglong; Cui, Honggang; MacKay, J Andrew

    2017-11-15

    Recombinant protein-polymer scaffolds such as elastin-like polypeptides (ELPs) offer drug-delivery opportunities including biocompatibility, monodispersity, and multifunctionality. We recently reported that the fusion of FK-506 binding protein 12 (FKBP) to an ELP nanoparticle (FSI) increases rapamycin (Rapa) solubility, suppresses tumor growth in breast cancer xenografts, and reduces side effects observed with free-drug controls. This new report significantly advances this carrier strategy by demonstrating the coassembly of two different ELP diblock copolymers containing drug-loading and tumor-targeting domains. A new ELP nanoparticle (ISR) was synthesized that includes the canonical integrin-targeting ligand (Arg-Gly-Asp, RGD). FSI and ISR mixed in a 1:1 molar ratio coassemble into bifunctional nanoparticles containing both the FKBP domain for Rapa loading and the RGD ligand for integrin binding. Coassembled nanoparticles were evaluated for bifunctionality by performing in vitro cell-binding and drug-retention assays and in vivo MDA-MB-468 breast tumor regression and tumor-accumulation studies. The bifunctional nanoparticle demonstrated superior cell target binding and similar drug retention to FSI; however, it enhanced the formulation potency, such that tumor growth was suppressed at a 3-fold lower dose compared to an untargeted FSI-Rapa control. This data suggests that ELP-mediated scaffolds are useful tools for generating multifunctional nanomedicines with potential activity in cancer.

  2. The Role of Mammalian Target of Rapamycin (mTOR in Insulin Signaling

    Directory of Open Access Journals (Sweden)

    Mee-Sup Yoon

    2017-10-01

    Full Text Available The mammalian target of rapamycin (mTOR is a serine/threonine kinase that controls a wide spectrum of cellular processes, including cell growth, differentiation, and metabolism. mTOR forms two distinct multiprotein complexes known as mTOR complex 1 (mTORC1 and mTOR complex 2 (mTORC2, which are characterized by the presence of raptor and rictor, respectively. mTOR controls insulin signaling by regulating several downstream components such as growth factor receptor-bound protein 10 (Grb10, insulin receptor substrate (IRS-1, F-box/WD repeat-containing protein 8 (Fbw8, and insulin like growth factor 1 receptor/insulin receptor (IGF-IR/IR. In addition, mTORC1 and mTORC2 regulate each other through a feedback loop to control cell growth. This review outlines the current understanding of mTOR regulation in insulin signaling in the context of whole body metabolism.

  3. Epigenetic aging signatures in mice livers are slowed by dwarfism, calorie restriction and rapamycin treatment.

    Science.gov (United States)

    Wang, Tina; Tsui, Brian; Kreisberg, Jason F; Robertson, Neil A; Gross, Andrew M; Yu, Michael Ku; Carter, Hannah; Brown-Borg, Holly M; Adams, Peter D; Ideker, Trey

    2017-03-28

    Global but predictable changes impact the DNA methylome as we age, acting as a type of molecular clock. This clock can be hastened by conditions that decrease lifespan, raising the question of whether it can also be slowed, for example, by conditions that increase lifespan. Mice are particularly appealing organisms for studies of mammalian aging; however, epigenetic clocks have thus far been formulated only in humans. We first examined whether mice and humans experience similar patterns of change in the methylome with age. We found moderate conservation of CpG sites for which methylation is altered with age, with both species showing an increase in methylome disorder during aging. Based on this analysis, we formulated an epigenetic-aging model in mice using the liver methylomes of 107 mice from 0.2 to 26.0 months old. To examine whether epigenetic aging signatures are slowed by longevity-promoting interventions, we analyzed 28 additional methylomes from mice subjected to lifespan-extending conditions, including Prop1df/df dwarfism, calorie restriction or dietary rapamycin. We found that mice treated with these lifespan-extending interventions were significantly younger in epigenetic age than their untreated, wild-type age-matched controls. This study shows that lifespan-extending conditions can slow molecular changes associated with an epigenetic clock in mice livers.

  4. Dysregulation of Mammalian Target of Rapamycin Signaling in Mouse Models of Autism.

    Science.gov (United States)

    Huber, Kimberly M; Klann, Eric; Costa-Mattioli, Mauro; Zukin, R Suzanne

    2015-10-14

    The mammalian target of rapamycin (mTOR) is a central regulator of a diverse array of cellular processes, including cell growth, proliferation, autophagy, translation, and actin polymerization. Components of the mTOR cascade are present at synapses and influence synaptic plasticity and spine morphogenesis. A prevailing view is that the study of mTOR and its role in autism spectrum disorders (ASDs) will elucidate the molecular mechanisms by which mTOR regulates neuronal function under physiological and pathological conditions. Although many ASDs arise as a result of mutations in genes with multiple molecular functions, they appear to converge on common biological pathways that give rise to autism-relevant behaviors. Dysregulation of mTOR signaling has been identified as a phenotypic feature common to fragile X syndrome, tuberous sclerosis complex 1 and 2, neurofibromatosis 1, phosphatase and tensin homolog, and potentially Rett syndrome. Below are a summary of topics covered in a symposium that presents dysregulation of mTOR as a unifying theme in a subset of ASDs. Copyright © 2015 the authors 0270-6474/15/3513836-07$15.00/0.

  5. Synergistic effect of rapamycin and cyclosporin A in the treatment of experimental autoimmune uveoretinitis.

    Science.gov (United States)

    Martin, D F; DeBarge, L R; Nussenblatt, R B; Chan, C C; Roberge, F G

    1995-01-15

    Immunosuppressive drugs currently available for the treatment of autoimmune diseases display a narrow therapeutic window between efficacy and toxic side effects. The use of combinations of drugs that have a synergistic effect may expand this window and reduce the risk of toxicity. We evaluated the combination effect of rapamycin (Rapa) and cyclosporin A (CsA) in an autoimmune disease model of the eye. The dose-effect relationship of Rapa with CsA was measured in vitro on the inhibition of proliferation of retinal S-Ag-primed lymphocytes. A median effect analysis was performed and a combination index (CI) calculated for 50% inhibition of proliferation. Rapa and CsA were markedly synergistic over a wide dose range (lowest CI = 0.31). Calculated dose reduction factors indicated that Rapa could be reduced nine-fold and CsA reduced five-fold when these drugs were used in combination. These reduced doses were tested in vivo for the treatment of experimental autoimmune uveoretinitis (EAU). Twelve of 15 rats treated with CsA, 2 mg/kg/day, developed EAU with a median severity of 2.5. Fourteen of 15 rats treated with Rapa, 0.01 mg/kg/day, developed EAU with a median severity of 3.25. Complete inhibition of EAU was achieved in all 15 animals treated with the combination of Rapa and CsA (combined vs CsA alone, p toxicity of these drugs for the treatment of autoimmune uveitis.

  6. Recent Advances in Mammalian Target of Rapamycin Inhibitor Use in Heart and Lung Transplantation.

    Science.gov (United States)

    Fine, Nowell M; Kushwaha, Sudhir S

    2016-12-01

    The mammalian target of rapamycin (mTOR) inhibitors sirolimus and everolimus are increasingly used in cardiothoracic transplantation. Several recent clinical trials have demonstrated their efficacy in combination with reduced cyclosporine dosing in de novo heart transplant recipients, in particular with everolimus. A number of other studies have demonstrated their efficacy for improving renal function and reducing calcineurin inhibitor use, attenuating cardiac allograft vasculopathy progression and reducing cytomegalovirus infections in maintenance heart transplant populations. A growing body of literature, including a small number of clinical trials, now describes the use mTOR inhibitors in lung transplant recipients. The benefits in this population include improved lung and renal function in limited studies. Considerably less evidence is available in pediatric heart transplantation, though similar indications in the maintenance therapy population have been described. The benefits of mTOR inhibitors must be weighed against the increased risk of adverse events and drug intolerance compared with other primary immunosuppressants, and discontinuation rates are particularly high in lung transplant recipients. The risks of surgical wound healing complications in transplant recipients receiving mTOR inhibitors previously or actively supported by mechanical circulatory support devices remains poorly described in the current literature. The current role and recent evidence for mTOR inhibitor use in heart and lung transplantation is examined in this review.

  7. Cloning and characterization of a novel erythroid cell-derived CNC family transcription factor heterodimerizing with the small Maf family proteins.

    Science.gov (United States)

    Itoh, K; Igarashi, K; Hayashi, N; Nishizawa, M; Yamamoto, M

    1995-08-01

    The chicken beta-globin enhancer is critical for the tissue- and developmental stage-specific expression of the beta-globin genes. This enhancer contains two indispensable cis elements, one containing two GATA sites and the other containing an NF-E2 site. To identify the putative transcription factor acting through the NF-E2 motif in the chicken beta-globin enhancer, we screened chicken cDNA libraries with a mouse p45 NF-E2 cDNA probe and isolated cDNA clones which encode a protein of 582 amino acid residues. This protein contains a region that includes the basic region-leucine zipper domain which is well conserved among members of the CNC family proteins (Cap 'n' collar, p45 NF-E2, LCR-F1, Nrf1, and Nrf2). Hence, we named this protein ECH (erythroid cell-derived protein with CNC homology). ECH is expressed abundantly in cultured erythroid cells undergoing terminal differentiation, peripheral erythrocytes, and some nonhematopoietic tissues. Since most of the cDNA clones obtained from the chicken erythrocyte cDNA library encoded ECH, ECH is likely the predominant CNC family protein present in avian peripheral erythrocytes. Like p45 NF-E2, ECH can heterodimerize with any of the small Maf family proteins and bind the NF-E2 site as a heterodimer in vitro. In a transfection assay, ECH transactivates transcription depending on the presence of NF-E2 sites on the reporter gene plasmid. These results indicate that ECH is likely a key regulator of avian erythropoiesis.

  8. Characterization of the metabolic phenotype of rapamycin-treated CD8+ T cells with augmented ability to generate long-lasting memory cells.

    Directory of Open Access Journals (Sweden)

    Shan He

    Full Text Available BACKGROUND: Cellular metabolism plays a critical role in regulating T cell responses and the development of memory T cells with long-term protections. However, the metabolic phenotype of antigen-activated T cells that are responsible for the generation of long-lived memory cells has not been characterized. DESIGN AND METHODS: Using lymphocytic choriomeningitis virus (LCMV peptide gp33-specific CD8(+ T cells derived from T cell receptor transgenic mice, we characterized the metabolic phenotype of proliferating T cells that were activated and expanded in vitro in the presence or absence of rapamycin, and determined the capability of these rapamycin-treated T cells to generate long-lived memory cells in vivo. RESULTS: Antigen-activated CD8(+ T cells treated with rapamycin gave rise to 5-fold more long-lived memory T cells in vivo than untreated control T cells. In contrast to that control T cells only increased glycolysis, rapamycin-treated T cells upregulated both glycolysis and oxidative phosphorylation (OXPHOS. These rapamycin-treated T cells had greater ability than control T cells to survive withdrawal of either glucose or growth factors. Inhibition of OXPHOS by oligomycin significantly reduced the ability of rapamycin-treated T cells to survive growth factor withdrawal. This effect of OXPHOS inhibition was accompanied with mitochondrial hyperpolarization and elevation of reactive oxygen species that are known to be toxic to cells. CONCLUSIONS: Our findings indicate that these rapamycin-treated T cells may represent a unique cell model for identifying nutrients and signals critical to regulating metabolism in both effector and memory T cells, and for the development of new methods to improve the efficacy of adoptive T cell cancer therapy.

  9. Sex-specific Tradeoffs With Growth and Fitness Following Life-span Extension by Rapamycin in an Outcrossing Nematode, Caenorhabditis remanei.

    Science.gov (United States)

    Lind, Martin I; Zwoinska, Martyna K; Meurling, Sara; Carlsson, Hanne; Maklakov, Alexei A

    2016-07-01

    Rapamycin inhibits the nutrient-sensing TOR pathway and extends life span in a wide range of organisms. Although life-span extension usually differs between the sexes, the reason for this is poorly understood. Because TOR influences growth, rapamycin likely affects life-history traits such as growth and reproduction. Sexes have different life-history strategies, and theory predicts that they will resolve the tradeoffs between growth, reproduction, and life span differently. Specifically, in taxa with female-biased sexual size dimorphism, reduced growth may have smaller effects on male fitness. We investigated the effects of juvenile, adult, or life-long rapamycin treatment on growth, reproduction, life span, and individual fitness in the outcrossing nematode Caenorhabditis remanei Life-long exposure to rapamycin always resulted in the strongest response, whereas postreproductive exposure did not affect life span. Although rapamycin resulted in longer life span and smaller size in males, male individual fitness was not affected. In contrast, size and fitness were negatively affected in females, whereas life span was only extended under high rapamycin concentrations. Our results support the hypothesis that rapamycin affects key life-history traits in a sex-specific manner. We argue that the fitness cost of life-span extension will be sex specific and propose that the smaller sex generally pay less while enjoying stronger life-span increase. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. Arsenic trioxide overcomes rapamycin-induced feedback activation of AKT and ERK signaling to enhance the anti-tumor effects in breast cancer.

    Science.gov (United States)

    Guilbert, Cynthia; Annis, Matthew G; Dong, Zhifeng; Siegel, Peter M; Miller, Wilson H; Mann, Koren K

    2013-01-01

    Inhibitors of the mammalian target of rapamycin (mTORi) have clinical activity; however, the benefits of mTOR inhibition by rapamycin and rapamycin-derivatives (rapalogs) may be limited by a feedback mechanism that results in AKT activation. Increased AKT activity resulting from mTOR inhibition can be a result of increased signaling via the mTOR complex, TORC2. Previously, we published that arsenic trioxide (ATO) inhibits AKT activity and in some cases, decreases AKT protein expression. Therefore, we propose that combining ATO and rapamycin may circumvent the AKT feedback loop and increase the anti-tumor effects. Using a panel of breast cancer cell lines, we find that ATO, at clinically-achievable doses, can enhance the inhibitory activity of the mTORi temsirolimus. In all cell lines, temsirolimus treatment resulted in AKT activation, which was decreased by concomitant ATO treatment only in those cell lines where ATO enhanced growth inhibition. Treatment with rapalog also results in activated ERK signaling, which is decreased with ATO co-treatment in all cell lines tested. We next tested the toxicity and efficacy of rapamycin plus ATO combination therapy in a MDA-MB-468 breast cancer xenograft model. The drug combination was well-tolerated, and rapamycin did not increase ATO-induced liver enzyme levels. In addition, combination of these drugs was significantly more effective at inhibiting tumor growth compared to individual drug treatments, which corresponded with diminished phospho-Akt and phospho-ERK levels when compared with rapamycin-treated tumors. Therefore, we propose that combining ATO and mTORi may overcome the feedback loop by decreasing activation of the MAPK and AKT signaling pathways.

  11. Arsenic trioxide overcomes rapamycin-induced feedback activation of AKT and ERK signaling to enhance the anti-tumor effects in breast cancer.

    Directory of Open Access Journals (Sweden)

    Cynthia Guilbert

    Full Text Available Inhibitors of the mammalian target of rapamycin (mTORi have clinical activity; however, the benefits of mTOR inhibition by rapamycin and rapamycin-derivatives (rapalogs may be limited by a feedback mechanism that results in AKT activation. Increased AKT activity resulting from mTOR inhibition can be a result of increased signaling via the mTOR complex, TORC2. Previously, we published that arsenic trioxide (ATO inhibits AKT activity and in some cases, decreases AKT protein expression. Therefore, we propose that combining ATO and rapamycin may circumvent the AKT feedback loop and increase the anti-tumor effects. Using a panel of breast cancer cell lines, we find that ATO, at clinically-achievable doses, can enhance the inhibitory activity of the mTORi temsirolimus. In all cell lines, temsirolimus treatment resulted in AKT activation, which was decreased by concomitant ATO treatment only in those cell lines where ATO enhanced growth inhibition. Treatment with rapalog also results in activated ERK signaling, which is decreased with ATO co-treatment in all cell lines tested. We next tested the toxicity and efficacy of rapamycin plus ATO combination therapy in a MDA-MB-468 breast cancer xenograft model. The drug combination was well-tolerated, and rapamycin did not increase ATO-induced liver enzyme levels. In addition, combination of these drugs was significantly more effective at inhibiting tumor growth compared to individual drug treatments, which corresponded with diminished phospho-Akt and phospho-ERK levels when compared with rapamycin-treated tumors. Therefore, we propose that combining ATO and mTORi may overcome the feedback loop by decreasing activation of the MAPK and AKT signaling pathways.

  12. Antifibrotic effect of rapamycin containing polyethylene glycol-coated alginate microcapsule in islet xenotransplantation.

    Science.gov (United States)

    Park, Heon-Seok; Kim, Ji-Won; Lee, Seung-Hwan; Yang, Hae Kyung; Ham, Dong-Sik; Sun, Cheng-Lin; Hong, Tae Ho; Khang, Gilson; Park, Chung-Gyu; Yoon, Kun-Ho

    2017-04-01

    Islet microencapsulation is an attractive strategy for the minimization or avoidance of life-long immunosuppression after transplantation. However, the clinical implementation of this technique is currently limited by incomplete biocompatibility. Thus, the aim of the present study was to demonstrate the improved biocompatibility of rapamycin-containing polyethylene glycol (Rapa-PEG)-coating on alginate microcapsules containing xenogeneic islets. The Rapa-PEG-coating on the alginate layer was observed using scanning electron microscopy (SEM) and the molecular cut-off weight of the microcapsules was approximately 70 kDa. The viabilities of the alginate-encapsulated and Rapa-PEG-coated alginate-encapsulated islets were lower than the viability of the naked islets just after encapsulation, but these the differences diminished over time in culture dishes. Rapa-PEG-coating on the alginate capsules effectively decreased the proliferation of macrophage cells compared to the non-coating and alginate coating of xenogeneic pancreas tissues. Glucose-stimulated insulin secretion did not significantly differ among the groups prior to transplantation. The random blood glucose levels of diabetic mice significantly improved following the transplantation of alginate-encapsulated and Rapa-PEG-coated alginate-encapsulated islets, but there were no significant differences between these two groups. However, there was a significant decrease in the number of microcapsules with fibrotic cell infiltration in the Rapa-PEG-coated alginate microcapsule group compared to the alginate microcapsule group. In conclusion, Rapa-PEG-coating might be an effective technique with which to improve the biocompatibility of microcapsules containing xenogeneic islets. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  13. Metabolomic evaluation of Mitomycin C and rapamycin in a personalized treatment of pancreatic cancer

    Science.gov (United States)

    Navarrete, Alicia; Armitage, Emily G; Musteanu, Monica; García, Antonia; Mastrangelo, Annalaura; Bujak, Renata; López-Casas, Pedro P; Hidalgo, Manuel; Barbas, Coral

    2014-01-01

    In a personalized treatment designed for a patient with pancreatic cancer resistant to other treatments, the success of Mitomycin C (MMC) has been highlighted. This was revealed in a murine xenograft tumor model encompassing pancreatic adenocarcinoma cells extracted from the patient. The patient was found to exhibit a biallelic inactivation of the PALB2 gene, involved in DNA repair in addition to another mutation in the TSC2 gene that induces susceptibility of the tumor to therapeutic targets of the PI3K-mTOR pathway. The aim of the study was to apply metabolomics to elucidate the modes of action of each therapy, suggesting why MMC was so successful in this patient and why it could be a more popular choice in future pancreatic cancer treatment. The effectiveness of MMC compared to rapamycin (RM), another relevant therapeutic agent has been evaluated through liquid- and gas-chromatography mass spectrometry-based metabolomic analyses of the xenograft tumors. The relative concentrations of many metabolites in the xenograft tumors were found to be increased by MMC relative to other treatments (RM and a combination of both), including a number that are involved in central carbon metabolism (CCM). Metabolic fingerprinting revealed statistically significantly altered pathways including, but not restricted to, the pentose phosphate pathway, glycolysis, TCA cycle, purine metabolism, fatty acid biosynthesis, in addition to many significant lipid and amino acid alterations. Given the genetic background of the patient, it was expected that the combined therapy would be most effective; however, the most effective was MMC alone. It is proposed that the effectiveness of MMC is owed to its direct effect on CCM, a vital region of tumor metabolism. PMID:25505613

  14. Intrauterine growth retardation promotes fetal intestinal autophagy in rats via the mechanistic target of rapamycin pathway.

    Science.gov (United States)

    Wang, Chao; Zhang, Ruiming; Zhou, Le; He, Jintian; Huang, Qiang; Siyal, Farman A; Zhang, Lili; Zhong, Xiang; Wang, Tian

    2017-08-31

    Intrauterine growth retardation (IUGR) impairs fetal intestinal development, and is associated with high perinatal morbidity and mortality. However, the mechanism underlying this intestinal injury is largely unknown. We aimed to investigate this mechanism through analysis of intestinal autophagy and related signaling pathways in a rat model of IUGR. Normal weight (NW) and IUGR fetuses were obtained from primiparous rats via ad libitum food intake and 50% food restriction, respectively. Maternal serum parameters, fetal body weight, organ weights, and fetal blood glucose were determined. Intestinal apoptosis, autophagy, and the mechanistic target of rapamycin (mTOR) signaling pathway were analyzed. The results indicated that maternal 50% food restriction reduced maternal serum glucose, bilirubin, and total cholesterol and produced IUGR fetuses, which had decreased body weight; blood glucose; and weights of the small intestine, stomach, spleen, pancreas, and kidney. Decreased Bcl-2 and increased Casp9 mRNA expression was observed in IUGR fetal intestines. Analysis of intestinal autophagy showed that the mRNA expression of WIPI1, MAP1LC3B, Atg5, and Atg14 was also increased, while the protein levels of p62 were decreased in IUGR fetuses. Compared to NW fetuses, IUGR fetuses showed decreased mTOR protein levels and enhanced mRNA expression of ULK1 and Beclin1 in the small intestine. In summary, the results indicated that maternal 50% food restriction on gestational days 10-21 reduced maternal serum glucose, bilirubin, and total cholesterol contents, and produced IUGR fetuses that had low blood glucose and reduced small intestine weight. Intestinal injury of IUGR fetuses caused by maternal food restriction might be due to enhanced apoptosis and autophagy via the mTOR signaling pathway.

  15. Protective Effects of the Mechanistic Target of Rapamycin against Excess Iron and Ferroptosis in Cardiomyocytes.

    Science.gov (United States)

    Baba, Yuichi; Higa, Jason K; Shimada, Briana K; Horiuchi, Kate M; Suhara, Tomohiro; Kobayashi, Motoi; Woo, Jonathan D; Aoyagi, Hiroko; Marh, Karra S; Kitaoka, Hiroaki; Matsui, Takashi

    2017-11-10

    Clinical studies suggest that myocardial iron is a risk factor for left ventricular remodeling in patients after myocardial infarction (MI). Ferroptosis was recently reported as a mechanism of iron-dependent non-apoptotic cell death. However, ferroptosis in the heart is not well understood. The mechanistic target of rapamycin (mTOR) protects the heart against pathological stimuli such as ischemia. To define the role of cardiac mTOR on cell survival in iron-mediated cell death, we examined cardiomyocyte (CM) cell viability under excess iron and ferroptosis conditions. Adult mouse CMs were isolated from cardiac-specific mTOR transgenic (mTOR-Tg), cardiac-specific mTOR knockout (mTOR-KO), or control mice. CMs were treated with ferric iron [Fe (III)]-citrate, erastin, a class 1 ferroptosis inducer, or Ras Selective Lethal 3 (RSL3), a class 2 ferroptosis inducer. Live/Dead Cell Viability Assays revealed that Fe (III)-citrate, erastin, and RSL3 induced cell death. Co-treatment with ferrostatin-1, a ferroptosis inhibitor, inhibited cell death in all conditions. mTOR overexpression suppressed Fe (III)-citrate, erastin, and RSL3-induced cell death, while mTOR deletion exaggerated cell death in these conditions. H2DCFDA (2',7'-dichlorodihydrofluorescein diacetate) measurement of reactive oxygen species (ROS) production showed that erastin-induced ROS production was significantly lower in mTOR-Tg versus control CMs. These findings suggest that ferroptosis is a significant type of cell death in CMs, and that mTOR plays an important role in protecting CMs against excess iron and ferroptosis, at least in part by regulating ROS production. Understanding the effects of mTOR in preventing iron-mediated cell death will provide a new therapy for patients with MI. Copyright © 2017, American Journal of Physiology-Heart and Circulatory Physiology.

  16. Regulation of cardiac miR-208a, an inducer of obesity, by rapamycin and nebivolol.

    Science.gov (United States)

    Gul, Rukhsana; Mahmood, Abuzar; Luck, Christian; Lum-Naihe, Kelly; Alfadda, Assim A; Speth, Robert C; Pulakat, Lakshmi

    2015-11-01

    Resistance to obesity is observed in rodents and humans treated with rapamycin (Rap) or nebivolol (Neb). Because cardiac miR-208a promotes obesity, this study tested whether the modes of actions of Rap and Neb involve inhibition of miR-208a. Mouse cardiomyocyte HL-1 cells and Zucker obese (ZO) rats were used to investigate regulation of cardiac miR-208a. Angiotensin II (Ang II) increased miR-208a expression in HL-1 cells. Pretreatment with an AT1 receptor (AT1R) antagonist, losartan (1 μM), antagonized this effect, whereas a phospholipase C inhibitor, U73122 (10 μM), and an NADPH oxidase inhibitor, apocynin (0.5 mM), did not. Ang II-induced increase in miR-208a was suppressed by Rap (10 nM), an inhibitor of nutrient sensor kinase mTORC1, and Neb (1 μM), a 3rd generation β-blocker that suppressed bioavailable AT1R binding of (125) I-Ang II. Thus, suppression of AT1R expression by Neb, inhibition of AT1R activation by losartan, and inhibition of AT1R-induced activation of mTORC1 by Rap attenuated the Ang II-induced increase in miR-208a. In ZO rats, Rap treatment (750 μg kg(-1)  day(-1) ; 12 weeks) reduced obesity despite similar food intake, suppressed cardiac miR-208a, and increased cardiac MED13, a suppresser of obesity. Rap and Neb suppressed cardiac miR-208a. Suppression of miR-208a and increase in MED13 correlated with attenuated weight gain despite leptin resistance. © 2015 The Obesity Society.

  17. Scopolamine rapidly increases mammalian target of rapamycin complex 1 signaling, synaptogenesis, and antidepressant behavioral responses.

    Science.gov (United States)

    Voleti, Bhavya; Navarria, Andrea; Liu, Rong-Jian; Banasr, Mounira; Li, Nanxin; Terwilliger, Rose; Sanacora, Gerard; Eid, Tore; Aghajanian, George; Duman, Ronald S

    2013-11-15

    Clinical studies report that scopolamine, an acetylcholine muscarinic receptor antagonist, produces rapid antidepressant effects in depressed patients, but the mechanisms underlying the therapeutic response have not been determined. The present study examines the role of the mammalian target of rapamycin complex 1 (mTORC1) and synaptogenesis, which have been implicated in the rapid actions of N-methyl-D-aspartate receptor antagonists. The influence of scopolamine on mTORC1 signaling was determined by analysis of the phosphorylated and activated forms of mTORC1 signaling proteins in the prefrontal cortex (PFC). The numbers and function of spine synapses were analyzed by whole cell patch clamp recording and two-photon image analysis of PFC neurons. The actions of scopolamine were examined in the forced swim test in the absence or presence of selective mTORC1 and glutamate receptor inhibitors. The results demonstrate that a single, low dose of scopolamine rapidly increases mTORC1 signaling and the number and function of spine synapses in layer V pyramidal neurons in the PFC. Scopolamine administration also produces an antidepressant response in the forced swim test that is blocked by pretreatment with the mTORC1 inhibitor or by a glutamate alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor antagonist. Taken together, the results demonstrate that the antidepressant actions of scopolamine require mTORC1 signaling and are associated with increased glutamate transmission, and synaptogenesis, similar to N-methyl-D-aspartate receptor antagonists. These findings provide novel targets for safer and more efficacious rapid-acting antidepressant agents. © 2013 Society of Biological Psychiatry.

  18. Effects of the Mammalian Target of Rapamycin Inhibitor Everolimus on Hepatitis C Virus Replication In Vitro and In Vivo.

    Science.gov (United States)

    Frey, A; Ecker, E-M; Piras-Straub, K; Walker, A; Hofmann, T G; Timm, J; Singer, B B; Gerken, G; Herzer, K

    2017-10-01

    The influence of immunosuppressants on hepatitis C virus (HCV) re-infection after liver transplantation, particularly mammalian target of rapamycin inhibitors, remains unclear. The aim of our study was to analyze the influence of everolimus (EVR) on HCV replication activity in the context of underlying molecular mechanisms, with focus on the pro-myelocytic leukemia protein (PML). HCV viral load was recorded in 40 patients with post-transplant HCV re-infection before and 8 weeks after introduction of EVR. An HCV cell culture replicon system for genotype (GT) 1b, GT2b, and GT3a was used to compare the influence of EVR on HCV replication for the respective genotypes in vitro. Fluorescence-activated cell-sorting analysis was used to test for effects on cell proliferation. PML expression was silenced with the use of small hairpin RNA constructs, and PML expression was quantified by means of quantitative real-time polymerase chain reaction. In patients with HCV, the viral load of GT1a and GT1b was hardly affected by EVR, whereas the viral load was reduced in patients with GT2a (P ≤ .0001) or GT3 infection (P ≤ .05). In vitro EVR impairs HCV replication activity of GT2a and GT3a up to 60% (P ≤ .0005), whereas in GT1b cells, HCV replication activity is increased by 50% (P ≤ .005). Replicon cell viability was not impaired. HCV replication activity is impaired in the absence of PML, which can be reversed by overexpression of PML isoforms. Furthermore, in the absence of PML, the effect of EVR on HCV replication activity is nearly abrogated. The mammalian target of rapamycin inhibitor EVR influences HCV replication via PML. The herein presented results suggest a genotype-dependent benefit for an EVR-based immunosuppressive regimen in patients with GT2a or GT3 re-infection after liver transplantation. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Stromal liver kinase B1 [STK11] signaling loss induces oviductal adenomas and endometrial cancer by activating mammalian Target of Rapamycin Complex 1.

    Directory of Open Access Journals (Sweden)

    Pradeep S Tanwar

    Full Text Available Germline mutations of the Liver Kinase b1 (LKB1/STK11 tumor suppressor gene have been linked to Peutz-Jeghers Syndrome (PJS, an autosomal-dominant, cancer-prone disorder in which patients develop neoplasms in several organs, including the oviduct, ovary, and cervix. We have conditionally deleted Lkb1 in Müllerian duct mesenchyme-derived cells of the female reproductive tract and observed expansion of the stromal compartment and hyperplasia and/or neoplasia of adjacent epithelial cells throughout the reproductive tract with paratubal cysts and adenomyomas in oviducts and, eventually, endometrial cancer. Examination of the proliferation marker phospho-histone H3 and mammalian Target Of Rapamycin Complex 1 (mTORC1 pathway members revealed increased proliferation and mTORC1 activation in stromal cells of both the oviduct and uterus. Treatment with rapamycin, an inhibitor of mTORC1 activity, decreased tumor burden in adult Lkb1 mutant mice. Deletion of the genes for Tuberous Sclerosis 1 (Tsc1 or Tsc2, regulators of mTORC1 that are downstream of LKB1 signaling, in the oviductal and uterine stroma phenocopies some of the defects observed in Lkb1 mutant mice, confirming that dysregulated mTORC1 activation in the Lkb1-deleted stroma contributes to the phenotype. Loss of PTEN, an upstream regulator of mTORC1 signaling, along with Lkb1 deletion significantly increased tumor burden in uteri and induced tumorigenesis in the cervix and vagina. These studies show that LKB1/TSC1/TSC2/mTORC1 signaling in mesenchymal cells is important for the maintenance of epithelial integrity and suppression of carcinogenesis in adjacent epithelial cells. Because similar changes in the stromal population are also observed in human oviductal/ovarian adenoma and endometrial adenocarcinoma patients, we predict that dysregulated mTORC1 activity by upstream mechanisms similar to those described in these model systems contributes to the pathogenesis of these human diseases.

  20. The heterodimeric glycoprotein hormone, GPA2/GPB5, regulates ion transport across the hindgut of the adult mosquito, Aedes aegypti.

    Directory of Open Access Journals (Sweden)

    Jean-Paul Paluzzi

    Full Text Available A family of evolutionarily old hormones is the glycoprotein cysteine knot-forming heterodimers consisting of alpha- (GPA and beta-subunits (GPB, which assemble by noncovalent bonds. In mammals, a common glycoprotein hormone alpha-subunit (GPA1 pairs with unique beta-subunits that establish receptor specificity, forming thyroid stimulating hormone (GPA1/TSHβ and the gonadotropins luteinizing hormone (GPA1/LHβ, follicle stimulating hormone (GPA1/FSHβ, choriogonadotropin (GPA1/CGβ. A novel glycoprotein heterodimer was identified in vertebrates by genome analysis, called thyrostimulin, composed of two novel subunits, GPA2 and GPB5, and homologs occur in arthropods, nematodes and cnidarians, implying that this neurohormone system existed prior to the emergence of bilateral metazoans. In order to discern possible physiological roles of this hormonal signaling system in mosquitoes, we have isolated the glycoprotein hormone genes producing the alpha- and beta-subunits (AedaeGPA2 and AedaeGPB5 and assessed their temporal expression profiles in the yellow and dengue-fever vector, Aedes aegypti. We have also isolated a putative receptor for this novel mosquito hormone, AedaeLGR1, which contains features conserved with other glycoprotein leucine-rich repeating containing G protein-coupled receptors. AedaeLGR1 is expressed in tissues of the alimentary canal such as the midgut, Malpighian tubules and hindgut, suggesting that this novel mosquito glycoprotein hormone may regulate ionic and osmotic balance. Focusing on the hindgut in adult stage A. aegypti, where AedaeLGR1 was highly enriched, we utilized the Scanning Ion-selective Electrode Technique (SIET to determine if AedaeGPA2/GPB5 modulated cation transport across this epithelial tissue. Our results suggest that AedaeGPA2/GPB5 does indeed participate in ionic and osmotic balance, since it appears to inhibit natriuresis and promote kaliuresis. Taken together, our findings imply this hormone may play an

  1. Rapamycin attenuates BAFF-extended proliferation and survival via disruption of mTORC1/2 signaling in normal and neoplastic B-lymphoid cells.

    Science.gov (United States)

    Zeng, Qingyu; Qin, Shanshan; Zhang, Hai; Liu, Beibei; Qin, Jiamin; Wang, Xiaoxue; Zhang, Ruijie; Liu, Chunxiao; Dong, Xiaoqing; Zhang, Shuangquan; Huang, Shile; Chen, Long

    2018-01-01

    B cell activating factor from the TNF family (BAFF) stimulates B-cell proliferation and survival, but excessive BAFF promotes the development of aggressive B cells leading to malignant and autoimmune diseases. Recently, we have reported that rapamycin, a macrocyclic lactone, attenuates human soluble BAFF (hsBAFF)-stimulated B-cell proliferation/survival by suppressing mTOR-mediated PP2A-Erk1/2 signaling pathway. Here, we show that the inhibitory effect of rapamycin on hsBAFF-promoted B cell proliferation/survival is also related to blocking hsBAFF-stimulated phosphorylation of Akt, S6K1, and 4E-BP1, as well as expression of survivin in normal and B-lymphoid (Raji and Daudi) cells. It appeared that both mTORC1 and mTORC2 were involved in the inhibitory activity of rapamycin, as silencing raptor or rictor enhanced rapamycin's suppression of hsBAFF-induced survivin expression and proliferation/viability in B cells. Also, PP242, an mTORC1/2 kinase inhibitor, repressed survivin expression, and cell proliferation/viability more potently than rapamycin (mTORC1 inhibitor) in B cells in response to hsBAFF. Of interest, ectopic expression of constitutively active Akt (myr-Akt) or constitutively active S6K1 (S6K1-ca), or downregulation of 4E-BP1 conferred resistance to rapamycin's attenuation of hsBAFF-induced survivin expression and B-cell proliferation/viability, whereas overexpression of dominant negative Akt (dn-Akt) or constitutively hypophosphorylated 4E-BP1 (4EBP1-5A), or downregulation of S6K1, or co-treatment with Akt inhibitor potentiated the inhibitory effects of rapamycin. The findings indicate that rapamycin attenuates excessive hsBAFF-induced cell proliferation/survival via blocking mTORC1/2 signaling in normal and neoplastic B-lymphoid cells. Our data underscore that rapamycin may be a potential agent for preventing excessive BAFF-evoked aggressive B-cell malignancies and autoimmune diseases. © 2017 Wiley Periodicals, Inc.

  2. Impairment of object recognition memory by rapamycin inhibition of mTOR in the amygdala or hippocampus around the time of learning or reactivation.

    Science.gov (United States)

    Jobim, Paulo F C; Pedroso, Thiago R; Werenicz, Aline; Christoff, Raissa R; Maurmann, Natasha; Reolon, Gustavo K; Schröder, Nadja; Roesler, Rafael

    2012-03-01

    The role of the basolateral complex of the amygdala (BLA) in recognition memory remains poorly understood. The mammalian target of rapamycin (mTOR) in the BLA and other brain areas has been implicated in synaptic plasticity and memory. We have recently shown that mTOR signaling in both the BLA and the dorsal hippocampus (DH) is required for formation and reconsolidation of inhibitory avoidance, a fear-motivated memory task. Here we examined the effects of infusions of the mTOR inhibitor rapamycin into the BLA before or after either training or reactivation on retention of novel object recognition (NOR) memory in rats, and compared the effects with those obtained using intra-DH infusions. Male Wistar rats received bilateral infusions of vehicle or rapamycin into the BLA or DH before or after NOR training or reactivation. Rapamycin impaired NOR retention tested 24h after training when given either before or immediately after training into the BLA or DH. Rapamycin also impaired retention measured 24h after reactivation when infused before reactivation into the BLA or DH, or immediately after reactivation into the BLA, but not when given 6h after reactivation into either the BLA or DH. The results suggest that mTOR signaling in the BLA and DH is involved in NOR memory formation and stabilization. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Differential Role of Rapamycin and Torin/KU63794 in Inflammatory Response of 264.7 RAW Macrophages Stimulated by CA-MRSA

    Directory of Open Access Journals (Sweden)

    Rebekah K. H. Shappley

    2014-01-01

    Full Text Available Background. Rapamycin suppresses the RAW264.7 macrophage mediated inflammatory response but in lower doses induces it. In the present study, we tested the suppression of the inflammatory response in the presence of mTOR 1 and 2 inhibitors, Torin and KU63794. Methods. RAW264.7 cells were stimulated for 18 hrs with 106 to 107 CFU/mL inocula of community-acquired- (CA- MRSA isolate, USA400 strain MW2, in the presence of Vancomycin. Then, in sequential experiments, we added Torin, KU63794, and Rapamycin alone and in various combinations. Supernatants were collected and assayed for TNF, IL-1, IL-6, INF, and NO. Results. Rapamycin induces 10–20% of the inflammatory cascade at dose of 0.1 ng/mL and suppresses it by 60% at dose of 10 ng/mL. The induction is abolished in the presence of Torin KU63794. Torin and KU63794 are consistently suppressing cytokine production 50–60%. Conclusions. There is a differential response between Rapamycin (mTOR-1 inhibitor and Torin KU63794 (mTOR 1 and 2 inhibitors. Torin and KU63794 exhibit a dose related suppression. Rapamycin exhibits a significant induction-suppression biphasic response. Knowledge of such response may allow manipulation of the septic inflammatory cascade for clinical advantages.

  4. De Novo Donor-Specific Antibody Formation in Tacrolimus-Based, Mycophenolate Versus Mammalian Target of Rapamycin Immunosuppressive Regimens.

    Science.gov (United States)

    Mithani, Zain; Gralla, Jane; Adebiyi, Oluwafisayo; Klem, Patrick; Cooper, James E; Wiseman, Alexander C

    2017-03-22

    De novo donor-specific antibody formation posttransplant is associated with decreased graft survival. It is not known whether mammalian target of rapamycin inhibitors may be advantageous or detrimental compared with mycophenolate in the prevention of de novo donor-specific antibody formation. We compared 66 kidney and kidney-pancreas transplant recipients who received tacrolimus, mammalian target of rapamycin inhibitor, and prednisone (group 1; 36 of whom received everolimus and 30 of whom received sirolimus) versus 132 patients who received tacrolimus, mycophenolate, and prednisone (group 2) matched for age, sex, race, and type/timing of transplant from 2007 to 2012. Rates of de novo donor-specific antibody formation were comparable between groups at 1, 6, and 12 months (16.7%, 25.8%, and 28.8% for group 1 vs 9.8%, 15.2%, and 22.0% for group 2). There were no significant differences in class (I, II, or mixed), strength (mean fluorescence intensity) of de novo donor-specific antibody, glomerular filtration rate, proteinuria levels, or acute rejection between the groups. In those with de novo donor-specific antibody by 6 months, acute rejection was more common versus those without de novo donor-specific antibody formation (24.3% vs 5.6% at 6 mo; P = .002), with rates of 27.0% versus 6.8% at 1 year (P = .001) and 40.7% versus 11.3% at 2 years (P < .001). An associated reduction in glomerular filtration rate also occurred. Mammalian target of rapamycin inhibitors were neither protective nor permissive for de novo donor-specific antibody formation versus mycophenolate when used with clinically relevant tacrolimus dosing regimens.

  5. Long-Term Alcohol-Induced Activation of Mammalian Target of Rapamycin is a Key Risk Factor of Epilepsy.

    Science.gov (United States)

    Fu, Xiaoling; Guo, Zhe; Gao, Chang; Chu, Qinying; Li, Jianhua; Ma, Hongying; Shu, Gangming

    2016-10-25

    BACKGROUND The aim of this study was to determine whether activation of mammalian target of rapamycin (mTOR) is a key epileptogenic mechanism in the development of alcohol-related seizure. MATERIAL AND METHODS C57BL/6 mice were administered 10% ethanol in drinking water for 9 weeks. Video-electroencephalography (EEG) monitoring was then used to assess seizure frequency after alcohol and rapamycin treatment. In addition, mouse neuroblastoma NG108-15 cells were treated ethanol for 3 days and subsequently treated with AKT inhibitor LY294002 for 2-12 h. The in vitro kinase assay was performed for determining mTOR activity. Western blot analysis was used to determine the expression of P-AKT, P-S6K, and P-S6. RESULTS Long-term ethanol treatment markedly increased the seizure frequency of C57/BL6 mice over time. Moreover, ethanol treatment increased the expression level of P-S6 over time. Ethanol-induced seizure can be reversed by rapamycin. In addition, the in vitro kinase assay showed mTOR activity was activated by ethanol. Compared with NG108-15 cells treated without both ethanol and LY294002, ethanol increased the expression level of P-AKT, P-S6K, and P-S6, whereas LY294002 had opposite effects on expression levels of these proteins. CONCLUSIONS Our findings indicate that long-term alcohol intake increases the risk of epilepsy via activation of mTOR signaling. Moreover, ethanol-induced mTOR activation may be dependent on the AKT-mTOR signaling pathway. The key molecules involved in AKT-mTOR signaling pathway may serve as potential targets in the treatment of epilepsy.

  6. Rapamycin and CHIR99021 Coordinate Robust Cardiomyocyte Differentiation From Human Pluripotent Stem Cells Via Reducing p53-Dependent Apoptosis.

    Science.gov (United States)

    Qiu, Xiao-Xu; Liu, Yang; Zhang, Yi-Fan; Guan, Ya-Na; Jia, Qian-Qian; Wang, Chen; Liang, He; Li, Yong-Qin; Yang, Huang-Tian; Qin, Yong-Wen; Huang, Shuang; Zhao, Xian-Xian; Jing, Qing

    2017-10-02

    Cardiomyocytes differentiated from human pluripotent stem cells can serve as an unexhausted source for a cellular cardiac disease model. Although small molecule-mediated cardiomyocyte differentiation methods have been established, the differentiation efficiency is relatively unsatisfactory in multiple lines due to line-to-line variation. Additionally, hurdles including line-specific low expression of endogenous growth factors and the high apoptotic tendency of human pluripotent stem cells also need to be overcome to establish robust and efficient cardiomyocyte differentiation. We used the H9-human cardiac troponin T-eGFP reporter cell line to screen for small molecules that promote cardiac differentiation in a monolayer-based and growth factor-free differentiation model. We found that collaterally treating human pluripotent stem cells with rapamycin and CHIR99021 during the initial stage was essential for efficient and reliable cardiomyocyte differentiation. Moreover, this method maintained consistency in efficiency across different human embryonic stem cell and human induced pluripotent stem cell lines without specifically optimizing multiple parameters (the efficiency in H7, H9, and UQ1 human induced pluripotent stem cells is 98.3%, 93.3%, and 90.6%, respectively). This combination also increased the yield of cardiomyocytes (1:24) and at the same time reduced medium consumption by about 50% when compared with the previous protocols. Further analysis indicated that inhibition of the mammalian target of rapamycin allows efficient cardiomyocyte differentiation through overcoming p53-dependent apoptosis of human pluripotent stem cells during high-density monolayer culture via blunting p53 translation and mitochondrial reactive oxygen species production. We have demonstrated that mammalian target of rapamycin exerts a stage-specific and multifaceted regulation over cardiac differentiation and provides an optimized approach for generating large numbers of functional

  7. Mechanistic Target of Rapamycin-Independent Antidepressant Effects of (R)-Ketamine in a Social Defeat Stress Model.

    Science.gov (United States)

    Yang, Chun; Ren, Qian; Qu, Youge; Zhang, Ji-Chun; Ma, Min; Dong, Chao; Hashimoto, Kenji

    2018-01-01

    The role of the mechanistic target of rapamycin (mTOR) signaling in the antidepressant effects of ketamine is controversial. In addition to mTOR, extracellular signal-regulated kinase (ERK) is a key signaling molecule in prominent pathways that regulate protein synthesis. (R)-Ketamine has a greater potency and longer-lasting antidepressant effects than (S)-ketamine. Here we investigated whether mTOR signaling and ERK signaling play a role in the antidepressant effects of two enantiomers. The effects of mTOR inhibitors (rapamycin and AZD8055) and an ERK inhibitor (SL327) on the antidepressant effects of ketamine enantiomers in the chronic social defeat stress (CSDS) model (n = 7 or 8) and on those of ketamine enantiomers in these signaling pathways in mouse brain regions were examined. The intracerebroventricular infusion of rapamycin or AZD8055 blocked the antidepressant effects of (S)-ketamine, but not (R)-ketamine, in the CSDS model. Furthermore, (S)-ketamine, but not (R)-ketamine, significantly attenuated the decreased phosphorylation of mTOR and its downstream effector, ribosomal protein S6 kinase, in the prefrontal cortex of susceptible mice after CSDS. Pretreatment with SL327 blocked the antidepressant effects of (R)-ketamine but not (S)-ketamine. Moreover, (R)-ketamine, but not (S)-ketamine, significantly attenuated the decreased phosphorylation of ERK and its upstream effector, mitogen-activated protein kinase/ERK kinase, in the prefrontal cortex and hippocampal dentate gyrus of susceptible mice after CSDS. This study suggests that mTOR plays a role in the antidepressant effects of (S)-ketamine, but not (R)-ketamine, and that ERK plays a role in (R)-ketamine's antidepressant effects. Thus, it is unlikely that the activation of mTOR signaling is necessary for antidepressant actions of (R)-ketamine. Copyright © 2017 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  8. Platelet-derived growth factor regulates vascular smooth muscle phenotype via mammalian target of rapamycin complex 1

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Jung Min; Yun, Sung Ji; Kim, Young Whan; Jin, Seo Yeon; Lee, Hye Sun [Medical Research Institute, Department of Pharmacology, Pusan National University School of Medicine, Yangsan (Korea, Republic of); Song, Sang Heon [Department of Internal Medicine, Pusan National University Hospital, Busan (Korea, Republic of); Shin, Hwa Kyoung [Department of Anatomy, Pusan National University School of Korean Medicine, Yangsan (Korea, Republic of); Bae, Sun Sik, E-mail: sunsik@pusan.ac.kr [Medical Research Institute, Department of Pharmacology, Pusan National University School of Medicine, Yangsan (Korea, Republic of)

    2015-08-14

    Mammalian target of rapamycin complex (mTORC) regulates various cellular processes including proliferation, growth, migration and differentiation. In this study, we showed that mTORC1 regulates platelet-derived growth factor (PDGF)-induced phenotypic conversion of vascular smooth muscle cells (VSMCs). Stimulation of contractile VSMCs with PDGF significantly reduced the expression of contractile marker proteins in a time- and dose-dependent manner. In addition, angiotensin II (AngII)-induced contraction of VSMCs was completely blocked by the stimulation of VSMCs with PDGF. PDGF-dependent suppression of VSMC marker gene expression was significantly blocked by inhibition of phosphatidylinositol 3-kinase (PI3K), extracellular signal-regulated kinase (ERK), and mTOR whereas inhibition of p38 MAPK had no effect. In particular, inhibition of mTORC1 by rapamycin or by silencing of Raptor significantly blocked the PDGF-dependent phenotypic change of VSMCs whereas silencing of Rictor had no effect. In addition, loss of AngII-dependent contraction by PDGF was significantly retained by silencing of Raptor. Inhibition of mTORC1 by rapamycin or by silencing of Raptor significantly blocked PDGF-induced proliferation of VSMCs. Taken together, we suggest that mTORC1 plays an essential role in PDGF-dependent phenotypic changes of VSMCs. - Graphical abstract: Regulation of VSMC phenotype by PDGF-dependent activation of mTORC1. - Highlights: • The expression of contractile marker proteins was reduced by PDGF stimulation. • PDGF-dependent phenotypic conversion of VSMCs was blocked by inhibition of mTOR. • PDGF-induced proliferation of VSMCs was attenuated by inhibition of mTORC1. • mTORC1 plays a critical role in PDGF-dependent phenotypic conversion of VSMCs.

  9. PEGylated lipid bilayer-wrapped nano-graphene oxides for synergistic co-delivery of doxorubicin and rapamycin to prevent drug resistance in cancers

    Science.gov (United States)

    Thapa, Raj Kumar; Byeon, Jeong Hoon; Choi, Han-Gon; Yong, Chul Soon; Kim, Jong Oh

    2017-07-01

    Nano-graphene oxide (nGO) is a carbon allotrope studied for its potential as carrier for chemotherapeutic delivery and its photoablation effects. However, interaction of nGO with blood components and the subsequent toxicities warrant a hybrid system for effective cancer drug delivery. Combination chemotherapy aids in effective cancer treatment and prevention of drug resistance. Therefore, in this study, we attempted to prepare polyethylene glycosylated (PEGylated) lipid bilayer-wrapped nGO co-loaded with doxorubicin (DOX) and rapamycin (RAPA), GOLDR, for the prevention and treatment of resistant cancers. Our results revealed a stable GOLDR formulation with appropriate particle size (∼170 nm), polydispersity (∼0.19) and drug loading. Free drug combination (DOX and RAPA) presented synergistic anticancer effects in MDA-MB-231, MCF-7, and BT474 cells. Treatment with GOLDR formulation maintained this synergism in treated cancer cells, which was further enhanced by the near infrared (NIR) laser irradiation-induced photothermal effects of nGO. Higher chromatin condensation and apoptotic body formation, and enhanced protein expression of apoptosis-related markers (Bax, p53, p21, and c-caspase 3) following GOLDR treatment in the presence of NIR laser treatment clearly suggests its superiority in effective chemo-photothermal therapy of resistant cancers. The hybrid nanosystem that we developed provides a basis for the effective use of GOLDR treatment in the prevention and treatment of resistant cancer types.

  10. Programmed Death-1 Inhibition of Phosphatidylinositol 3-Kinase/AKT/Mechanistic Target of Rapamycin Signaling Impairs Sarcoidosis CD4+ T Cell Proliferation.

    Science.gov (United States)

    Celada, Lindsay J; Rotsinger, Joseph E; Young, Anjuli; Shaginurova, Guzel; Shelton, Debresha; Hawkins, Charlene; Drake, Wonder P

    2017-01-01

    Patients with progressive sarcoidosis exhibit increased expression of programmed death-1 (PD-1) receptor on their CD4+ T cells. Up-regulation of this marker of T cell exhaustion is associated with a reduction in the proliferative response to T cell receptor (TCR) stimulation, a defect that is reversed by PD-1 pathway blockade. Genome-wide association studies and microarray analyses have correlated signaling downstream from the TCR with sarcoidosis disease severity, but the mechanism is not yet known. Reduced phosphatidylinositol 3-kinase (PI3K)/AKT expression inhibits proliferation by inhibiting cell cycle progression. To test the hypothesis that PD-1 expression attenuates TCR-dependent activation of PI3K/AKT activity in progressive systemic sarcoidosis, we analyzed PI3K/AKT/mechanistic target of rapamycin (mTOR) expression at baseline and after PD-1 pathway blockade in CD4+ T cells isolated from patients with sarcoidosis and healthy control subjects. We confirmed an increased percentage of PD-1+ CD4+ T cells and reduced proliferative capacity in patients with sarcoidosis compared with healthy control subjects (P sarcoidosis CD4+ T cell proliferative capacity is secondary to altered expression of key mediators of cell cycle progression, including the PI3K/AKT/mTOR pathway, via PD-1 up-regulation. This supports the concept that PD-1 up-regulation drives the immunologic deficits associated with sarcoidosis severity by inducing signaling aberrancies in key mediators of cell cycle progression.

  11. Proton and nitrogen sequential assignments and secondary structure determination of the human FK506 and rapamycin binding protein

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, M.K.; Michnick, S.W.; Karplus, M.; Schreiber, S.L. (Harvard Univ., Cambridge, MA (USA))

    1991-05-14

    Sequential {sup 1}H and {sup 15}N assignments of human FKBP, a cytosolic binding protein for the immunosuppressive agents FK506 and rapamycin, are reported. A combination of homonuclear and relayed heteronuclear experiments has enabled assignment of 98 of 99 backbone amide NHs, 119 of 120 C{sup {alpha}}Hs, 97 of 99 non-proline amide {sup 15}Ns, and 375 of 412 side-chain resonances of this 107-residue protein. Long-range NOEs are used to demonstrate that FKBP has a novel folding topology consisting of a five-stranded antiparallel {beta} sheet with +3, +1, {minus}3, +1 loop connectivity.

  12. Characterization of zinc transporter 8 (ZnT8) antibodies in autoimmune diabetic patients from Argentinian population using monomeric, homodimeric, and heterodimeric ZnT8 antigen variants.

    Science.gov (United States)

    Faccinetti, Natalia I; Guerra, Luciano L; Penas Steinhardt, Alberto; Iacono, Ruben F; Frechtel, Gustavo D; Trifone, Liliana; Poskus, Edgardo; Trabucchi, Aldana; Valdez, Silvina N

    2016-02-01

    In order to gain further knowledge of the structure of zinc transporter 8 (ZnT8) epitopes, we studied the role of the amino acid at position 325 in the antigen and its dimeric conformation for autoantibodies to ZnT8 (ZnT8A) recognition. For this purpose, several ZnT8 C-terminal domain variants were designed: monomer carrying Arg325 or Trp325, homo-dimers ZnT8-Arg-Arg325 and ZnT8-Trp-Trp325, and hetero-dimer ZnT8-Arg-Trp325. Two groups of Argentinian diabetic patients were subjected to analysis using [(35)S]-ZnT8 variants by radioligand binding assay (RBA): i) 100 new-onset, insulin-dependent, type 1 diabetic patients and ii) 282 slowly progressing to insulin requirement, non-obese adult-onset diabetic patients. In addition, 50 type 1 diabetic patients and 100 normal control sera provided by the American Diabetes Association (ADA) were evaluated in order to calculate the sensitivity and specificity of ZnT8A assays for each antigenic variant. Other routine β-cell autoantibodies were also tested by RBA. Of the 100 Argentinian type 1 diabetic patients, 65 were ZnT8A+. Out of them, 8 patients recognized all recombinant forms of ZnT8 and most patients (56) reacted against the heterodimer. Additionally, out of 282 non-obese adult-onset diabetic patients 46 were ZnT8A+, whereas 29 patients recognized only dimers. Besides, exclusive reactivity against ZnT8A was found in 9.0% for type 1 diabetes mellitus and 10.3% for non-obese adult-onset diabetic patients. Significantly higher signal values in RBA were obtained with the heterodimeric variant. An increased detection of humoral autoimmunity was found in both groups when ZnT8A was employed in combination with the other β-cell autoantibodies. The inclusion of homodimeric immunoreactive peptides revealed the existence of quaternary structure-defined epitopes probably resembling the actual state of the autoantigen in vivo. Finally, the differential profiles of ZnT8A exhibited by type 1 and non-obese adult-onset diabetic

  13. Mammalian target of rapamycin is essential for cardiomyocyte survival and heart development in mice

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Pengpeng [Key Laboratory of Swine Genetics and Breeding, Ministry of Agriculture, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070 (China); Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070 (China); Department of Animal Sciences, Purdue University, West Lafayette, IN 47907 (United States); Shan, Tizhong; Liang, Xinrong [Department of Animal Sciences, Purdue University, West Lafayette, IN 47907 (United States); Deng, Changyan [Key Laboratory of Swine Genetics and Breeding, Ministry of Agriculture, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070 (China); Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070 (China); Kuang, Shihuan, E-mail: skuang@purdue.edu [Department of Animal Sciences, Purdue University, West Lafayette, IN 47907 (United States)

    2014-09-12

    Highlights: • mTOR is a critical regulator of many biological processes yet its function in heart is not well understood. • MCK-Cre/Mtor{sup flox/flox} mice were established to delete Mtor in cardiomyocytes. • The mTOR-mKO mice developed normally but die prematurely within 5 weeks after birth due to heart disease. • The mTOR-mKO mice had dilated myocardium and increased cell death. • mTOR-mKO hearts had reduced expression of metabolic genes and activation of mTOR target proteins. - Abstract: Mammalian target of rapamycin (mTOR) is a critical regulator of protein synthesis, cell proliferation and energy metabolism. As constitutive knockout of Mtor leads to embryonic lethality, the in vivo function of mTOR in perinatal development and postnatal growth of heart is not well defined. In this study, we established a muscle-specific mTOR conditional knockout mouse model (mTOR-mKO) by crossing MCK-Cre and Mtor{sup flox/flox} mice. Although the mTOR-mKO mice survived embryonic and perinatal development, they exhibited severe postnatal growth retardation, cardiac muscle pathology and premature death. At the cellular level, the cardiac muscle of mTOR-mKO mice had fewer cardiomyocytes due to apoptosis and necrosis, leading to dilated cardiomyopathy. At the molecular level, the cardiac muscle of mTOR-mKO mice expressed lower levels of fatty acid oxidation and glycolysis related genes compared to the WT littermates. In addition, the mTOR-mKO cardiac muscle had reduced Myh6 but elevated Myh7 expression, indicating cardiac muscle degeneration. Furthermore, deletion of Mtor dramatically decreased the phosphorylation of S6 and AKT, two key targets downstream of mTORC1 and mTORC2 mediating the normal function of mTOR. These results demonstrate that mTOR is essential for cardiomyocyte survival and cardiac muscle function.

  14. Alcohol consumption mitigates apoptosis and mammalian target of rapamycin signaling in myocardium.

    Science.gov (United States)

    Elmadhun, Nassrene Y; Sabe, Ashraf A; Lassaletta, Antonio D; Sellke, Frank W

    2014-06-01

    Epidemiologic studies have shown that individuals who consume low to moderate alcohol have a lower risk of cardiovascular disease developing compared with abstainers. Although experimental studies confirmed this observation, the effect of alcohol on ischemic myocardium is still unclear. We developed a clinically relevant animal model of chronic myocardial ischemia to investigate the effects of moderate alcohol consumption on the myocardium. Fourteen Yorkshire swine underwent placement of an ameroid constrictor to induce chronic myocardial ischemia. Postoperatively, one group was supplemented with 90 mL 50% EtOH daily (n = 7) and one group was supplemented with 80 g sucrose daily to normalize caloric intake between groups (n = 7). After 7 weeks, all animals underwent sternotomy, and harvest of the chronically ischemic myocardium and nonischemic myocardium. Tissues were analyzed for protein expression and stained for apoptosis quantification. In the ischemic myocardium, alcohol down-regulated the following proapoptotic proteins: tumor necrosis factor-α, forkhead box protein 03, BCL2-associated death promoter, and cysteine aspartic acid-specific protease 9; up-regulated the following prosurvival proteins: 5'adenosine monophosphate-activated protein kinase, phosphorylated 5'adenosine monophosphate-activated protein kinase, and phosphorylated forkhead box protein 03; and down-regulated mammalian target of rapamycin (MTOR) signaling by down-regulating MTOR, phosphorylated MTOR, and up-regulating Deptor. In the nonischemic myocardium, alcohol up-regulated prosurvival proteins: protein kinase B, phosphorylated protein kinase B, phosphorylated B-cell CLL/lymphoma 2, 5'adenosine monophosphate-activated protein kinase, phosphorylated BCL2-associated death promoter, phosphorylated forkhead box protein 03, and down-regulated MTOR signaling by down-regulating phosphorylated MTOR and up-regulating Deptor. Alcohol also decreased cell death as measured by terminal

  15. Rapamycin Inhibits Expression of Elongation of Very-long-chain Fatty Acids 1 and Synthesis of Docosahexaenoic Acid in Bovine Mammary Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Zhixin Guo

    2016-11-01

    Full Text Available Mammalian target of rapamycin complex 1 (mTORC1 is a central regulator of cell growth and metabolism and is sufficient to induce specific metabolic processes, including de novo lipid biosynthesis. Elongation of very-long-chain fatty acids 1 (ELOVL1 is a ubiquitously expressed gene and the product of which was thought to be associated with elongation of carbon (C chain in fatty acids. In the present study, we examined the effects of rapamycin, a specific inhibitor of mTORC1, on ELOVL1 expression and docosahexaenoic acid (DHA, C22:6 n-3 synthesis in bovine mammary epithelial cells (BMECs. We found that rapamycin decreased the relative abundance of ELOVL1 mRNA, ELOVL1 expression and the level of DHA in a time-dependent manner. These data indicate that ELOVL1 expression and DHA synthesis are regulated by mTORC1 in BMECs.

  16. Effects of ketamine administration on mTOR and reticulum stress signaling pathways in the brain after the infusion of rapamycin into prefrontal cortex.

    Science.gov (United States)

    Abelaira, Helena M; Réus, Gislaine Z; Ignácio, Zuleide M; Dos Santos, Maria Augusta B; de Moura, Airam B; Matos, Danyela; Demo, Júlia P; da Silva, Júlia B I; Michels, Monique; Abatti, Mariane; Sonai, Beatriz; Dal Pizzol, Felipe; Carvalho, André F; Quevedo, João

    2017-04-01

    Recent studies show that activation of the mTOR signaling pathway is required for the rapid antidepressant actions of glutamate N-methyl-D-aspartate (NMDA) receptor antagonists. A relationship between mTOR kinase and the endoplasmic reticulum (ER) stress pathway, also known as the unfolded protein response (UPR) has been shown. We evaluate the effects of ketamine administration on the mTOR signaling pathway and proteins of UPR in the prefrontal cortex (PFC), hippocampus, amygdala and nucleus accumbens, after the inhibiton of mTOR signaling in the PFC. Male adult Wistar rats received pharmacological mTOR inhibitor, rapamycin (0.2 nmol), or vehicle into the PFC and then a single dose of ketamine (15 mg/kg, i.p.). The immunocontent of mTOR, eukaryotic initiation factor 4E-binding protein 1 (4E-BP1), eukaryotic elongation factor 2 kinase (eEF2K) homologous protein (CHOP), PKR-like ER kinase (PERK) and inositol-requiring enzyme 1 (IRE1) - alpha were determined in the brain. The mTOR levels were reduced in the rapamycin group treated with saline and ketamine in the PFC; p4EBP1 levels were reduced in the rapamycin group treated with ketamine in the PFC and nucleus accumbens; the levels of peEF2K were increased in the PFC in the vehicle group treated with ketamine and reduced in the rapamycin group treated with ketamine. The PERK and IRE1-alpha levels were decreased in the PFC in the rapamycin group treated with ketamine. Our results suggest that mTOR signaling inhibition by rapamycin could be involved, at least in part, with the mechanism of action of ketamine; and the ketamine antidepressant on ER stress pathway could be also mediated by mTOR signaling pathway in certain brain structures. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Target-of-rapamycin complex 1 (Torc1) signaling modulates cilia size and function through protein synthesis regulation

    Science.gov (United States)

    Yuan, Shiaulou; Li, Jade; Diener, Dennis R.; Choma, Michael A.; Rosenbaum, Joel L.; Sun, Zhaoxia

    2012-01-01

    The cilium serves as a cellular antenna by coordinating upstream environmental cues with numerous downstream signaling processes that are indispensable for the function of the cell. This role is supported by the revelation that defects of the cilium underlie an emerging class of human disorders, termed “ciliopathies.” Although mounting interest in the cilium has demonstrated the essential role that the organelle plays in vertebrate development, homeostasis, and disease pathogenesis, the mechanisms regulating cilia morphology and function remain unclear. Here, we show that the target-of-rapamycin (TOR) growth pathway modulates cilia size and function during zebrafish development. Knockdown of tuberous sclerosis complex 1a (tsc1a), which encodes an upstream inhibitor of TOR complex 1 (Torc1), increases cilia length. In contrast, treatment of embryos with rapamycin, an inhibitor of Torc1, shortens cilia length. Overexpression of ribosomal protein S6 kinase 1 (S6k1), which encodes a downstream substrate of Torc1, lengthens cilia. Furthermore, we provide evidence that TOR-mediated cilia assembly is evolutionarily conserved and that protein synthesis is essential for this regulation. Finally, we demonstrate that TOR signaling and cilia length are pivotal for a variety of downstream ciliary functions, such as cilia motility, fluid flow generation, and the establishment of left-right body asymmetry. Our findings reveal a unique role for the TOR pathway in regulating cilia size through protein synthesis and suggest that appropriate and defined lengths are necessary for proper function of the cilium. PMID:22308353

  18. Inducing autophagy by rapamycin before, but not after, the formation of plaques and tangles ameliorates cognitive deficits.

    Directory of Open Access Journals (Sweden)

    Smita Majumder

    Full Text Available Previous studies have shown that inducing autophagy ameliorates early cognitive deficits associated with the build-up of soluble amyloid-β (Aβ. However, the effects of inducing autophagy on plaques and tangles are yet to be determined. While soluble Aβ and tau represent toxic species in Alzheimer's disease (AD pathogenesis, there is well documented evidence that plaques and tangles also are detrimental to normal brain function. Thus, it is critical to assess the effects of inducing autophagy in an animal model with established plaques and tangles. Here we show that rapamycin, when given prophylactically to 2-month-old 3xTg-AD mice throughout their life, induces autophagy and significantly reduces plaques, tangles and cognitive deficits. In contrast, inducing autophagy in 15-month-old 3xTg-AD mice, which have established plaques and tangles, has no effects on AD-like pathology and cognitive deficits. In conclusion, we show that autophagy induction via rapamycin may represent a valid therapeutic strategy in AD when administered early in the disease progression.

  19. Mammalian target of rapamycin hyperactivity mediates the detrimental effects of a high sucrose diet on Alzheimer's disease pathology.

    Science.gov (United States)

    Orr, Miranda E; Salinas, Angelica; Buffenstein, Rochelle; Oddo, Salvatore

    2014-06-01

    High sugar consumption and diabetes increase the risk of developing Alzheimer's disease (AD) by unknown mechanisms. Using an animal model of AD, here we show that high sucrose intake induces obesity with changes in central and peripheral insulin signaling. These pre-diabetic changes are associated with an increase in amyloid-β production and deposition. Moreover, high sucrose ingestion exacerbates tau phosphorylation by increasing Cdk5 activity. Mechanistically, the sucrose-mediated increase in AD-like pathology results from hyperactive mammalian target of rapamycin (mTOR), a key nutrient sensor important in regulating energy homeostasis. Specifically, we show that rapamycin, an mTOR inhibitor, prevents the detrimental effects of sucrose in the brain without altering changes in peripheral insulin resistance. Overall, our data suggest that high sucrose intake and dysregulated insulin signaling, which are known to contribute to the occurrence of diabetes, increase the risk of developing AD by upregulating brain mTOR signaling. Therefore, early interventions to modulate mTOR activity in individuals at high risk of developing diabetes may decrease their AD susceptibility. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Rapamycin inhibits IGF-1-mediated up-regulation of MDM2 and sensitizes cancer cells to chemotherapy.

    Directory of Open Access Journals (Sweden)

    Wei Du

    Full Text Available The Murine Double Minute 2 (MDM2 protein is a key regulator of cell proliferation and apoptosis that acts primarily by inhibiting the p53 tumor suppressor. Similarly, the PI3-Kinase (PI3K/AKT pathway is critical for growth factor-mediated cell survival. Additionally, it has been reported that AKT can directly phosphorylate and activate MDM2. In this study, we show that IGF-1 up-regulates MDM2 protein levels in a PI3K/AKT-dependent manner. Inhibition of mTOR by rapamycin or expression of a dominant negative eukaryotic initiation factor 4E binding protein 1 (4EBP1 mutant protein, as well as ablation of eukaryotic initiation factor 4E (eIF4E, efficiently abolishes IGF-1-mediated up-regulation of MDM2. In addition, we show that rapamycin effectively inhibits MDM2 expression and sensitizes cancer cells to chemotherapy. Taken together, this study reveals a novel mechanism by which IGF-1 activates MDM2 via the mTOR pathway, and that pharmacologic inhibition of mTOR combined with chemotherapy may be more effective in treatment of a subset of cancers harboring increased MDM2 activation.

  1. Enhanced genetic modification of adult growth factor mobilized peripheral blood hematopoietic stem and progenitor cells with rapamycin.

    Science.gov (United States)

    Li, Lijing; Torres-Coronado, Mónica; Gu, Angel; Rao, Anitha; Gardner, Agnes M; Epps, Elizabeth W; Gonzalez, Nancy; Tran, Chy-Anh; Wu, Xiwei; Wang, Jin-Hui; DiGiusto, David L

    2014-10-01

    Genetic modification of adult human hematopoietic stem and progenitor cells (HSPCs) with lentiviral vectors leads to long-term gene expression in the progeny of the HSPCs and has been used to successfully treat several monogenic diseases. In some cases, the gene-modified cells have a selective growth advantage over nonmodified cells and eventually are the dominant engrafted population. However, in disease indications for which the gene-modified cells do not have a selective advantage, optimizing transduction of HSPC is paramount to successful stem cell-based gene therapy. We demonstrate here that transduction of adult CD34+ HSPCs with lentiviral vectors in the presence of rapamycin, a widely used mTORC1 inhibitor, results in an approximately threefold increase in stable gene marking with minimal effects on HSPC growth and differentiation. Using this approach, we have demonstrated that we can enhance the frequency of gene-modified HSPCs that give rise to clonogenic progeny in vitro without excessive increases in the number of vector copies per cell or changes in integration pattern. The genetic marking of HSPCs and expression of transgenes is durable, and transplantation of gene-modified HSPCs into immunodeficient mice results in high levels of gene marking of the lymphoid and myeloid progeny in vivo. The prior safe clinical history of rapamycin in other applications supports the use of this compound to generate gene-modified autologous HSPCs for our HIV gene therapy clinical trials. ©AlphaMed Press.

  2. l-Tryptophan-mediated Enhancement of Susceptibility to Nonalcoholic Fatty Liver Disease Is Dependent on the Mammalian Target of Rapamycin*

    Science.gov (United States)

    Osawa, Yosuke; Kanamori, Hiromitsu; Seki, Ekihiro; Hoshi, Masato; Ohtaki, Hirofumi; Yasuda, Yoichi; Ito, Hiroyasu; Suetsugu, Atsushi; Nagaki, Masahito; Moriwaki, Hisataka; Saito, Kuniaki; Seishima, Mitsuru

    2011-01-01

    Nonalcoholic fatty liver disease is one of the most common liver diseases. l-Tryptophan and its metabolite serotonin are involved in hepatic lipid metabolism and inflammation. However, it is unclear whether l-tryptophan promotes hepatic steatosis. To explore this issue, we examined the role of l-tryptophan in mouse hepatic steatosis by using a high fat and high fructose diet (HFHFD) model. l-Tryptophan treatment in combination with an HFHFD exacerbated hepatic steatosis, expression of HNE-modified proteins, hydroxyproline content, and serum alanine aminotransaminase levels, whereas l-tryptophan alone did not result in these effects. We also found that l-tryptophan treatment increases serum serotonin levels. The introduction of adenoviral aromatic amino acid decarboxylase, which stimulates the serotonin synthesis from l-tryptophan, aggravated hepatic steatosis induced by the HFHFD. The fatty acid-induced accumulation of lipid was further increased by serotonin treatment in cultured hepatocytes. These results suggest that l-tryptophan increases the sensitivity to hepatic steatosis through serotonin production. Furthermore, l-tryptophan treatment, adenoviral AADC introduction, and serotonin treatment induced phosphorylation of the mammalian target of rapamycin (mTOR), and a potent mTOR inhibitor rapamycin attenuated hepatocyte lipid accumulation induced by fatty acid with serotonin. These results suggest the importance of mTOR activation for the exacerbation of hepatic steatosis. In conclusion, l-tryptophan exacerbates hepatic steatosis induced by HFHFD through serotonin-mediated activation of mTOR. PMID:21841000

  3. West nile virus-induced activation of mammalian target of rapamycin complex 1 supports viral growth and viral protein expression.

    Science.gov (United States)

    Shives, Katherine D; Beatman, Erica L; Chamanian, Mastooreh; O'Brien, Caitlin; Hobson-Peters, Jody; Beckham, J David

    2014-08-01

    Since its introduction in New York City, NY, in 1999, West Nile virus (WNV) has spread to all 48 contiguous states of the United States and is now the leading cause of epidemic encephalitis in North America. As a member of the family Flaviviridae, WNV is part of a group of clinically important human pathogens, including dengue virus and Japanese encephalitis virus. The members of this family of positive-sense, single-stranded RNA viruses have limited coding capacity and are therefore obligated to co-opt a significant amount of cellular factors to translate their genomes effectively. Our previous work has shown that WNV growth was independent of macroautophagy activation, but the role of the evolutionarily conserved mammalian target of rapamycin (mTOR) pathway during WNV infection was not well understood. mTOR is a serine/threonine kinase that acts as a central cellular censor of nutrient status and exercises control of vital anabolic and catabolic cellular responses such as protein synthesis and autophagy, respectively. We now show that WNV activates mTOR and cognate downstream activators of cap-dependent protein synthesis at early time points postinfection and that pharmacologic inhibition of mTOR (KU0063794) significantly reduced WNV growth. We used an inducible Raptor and Rictor knockout mouse embryonic fibroblast (MEF) system to further define the role of mTOR complexes 1 and 2 in WNV growth and viral protein synthesis. Following inducible genetic knockout of the major mTOR cofactors raptor (TOR complex 1 [TORC1]) and rictor (TORC2), we now show that TORC1 supports flavivirus protein synthesis via cap-dependent protein synthesis pathways and supports subsequent WNV growth. Since its introduction in New York City, NY, in 1999, West Nile virus (WNV) has spread to all 48 contiguous states in the United States and is now the leading cause of epidemic encephalitis in North America. Currently, the mechanism by which flaviviruses such as WNV translate their genomes in

  4. Analysis of various types of single-polypeptide-chain (sc) heterodimeric A{sub 2A}R/D{sub 2}R complexes and their allosteric receptor–receptor interactions

    Energy Technology Data Exchange (ETDEWEB)

    Kamiya, Toshio, E-mail: kamiya@z2.keio.jp [Department of Molecular Cell Signaling, Tokyo Metropolitan Institute for Neuroscience, 2-6 Musashidai, Fuchu, Tokyo 183-8526 (Japan); Department of Neurology, Tokyo Metropolitan Institute for Neuroscience, 2-6 Musashidai, Fuchu, Tokyo 183-8526 (Japan); Cell Biology Laboratory, School of Pharmaceutical Sciences, Kinki University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502 (Japan); Yoshioka, Kazuaki; Nakata, Hiroyasu [Department of Molecular Cell Signaling, Tokyo Metropolitan Institute for Neuroscience, 2-6 Musashidai, Fuchu, Tokyo 183-8526 (Japan)

    2015-01-09

    Highlights: • Various scA{sub 2A}R/D{sub 2}R constructs, with spacers between the two receptors, were created. • Using whole cell binding assay, constructs were examined for their binding activity. • Although the apparent ratio of A{sub 2A}R to D{sub 2}R binding sites should be 1, neither was 1. • Counter agonist-independent binding cooperativity occurred in context of scA{sub 2A}R/D{sub 2}R. - Abstract: Adenosine A{sub 2A} receptor (A{sub 2A}R) heteromerizes with dopamine D{sub 2} receptor (D{sub 2}R). However, these class A G protein-coupled receptor (GPCR) dimers are not fully formed, but depend on the equilibrium between monomer and dimer. In order to stimulate the heteromerization, we have previously shown a successful design for a fusion receptor, single-polypeptide-chain (sc) heterodimeric A{sub 2A}R/D{sub 2}R complex. Here, using whole cell binding assay, six more different scA{sub 2A}R/D{sub 2}R constructs were examined. Not only in scA{sub 2A}R/D{sub 2}R ‘liberated’ with longer spacers between the two receptors, which confer the same configuration as the prototype, the A{sub 2A}R-odr4TM-D{sub 2L}R, but differ in size (Forms 1–3), but also in scA{sub 2A}R/D{sub 2L}R (Form 6) fused with a transmembrane (TM) of another type II TM protein, instead of odr4TM, neither of their fixed stoichiometry (the apparent ratios of A{sub 2A}R to D{sub 2}R binding sites) was 1, suggesting their compact folding. This suggests that type II TM, either odr4 or another, facilitates the equilibrial process of the dimer formation between A{sub 2A}R and D{sub 2L}R, resulting in the higher-order oligomer formation from monomer of scA{sub 2A}R/D{sub 2L}R itself. Also, in the reverse type scA{sub 2A}R/D{sub 2L}R, i.e., the D{sub 2L}R-odr4TM-A{sub 2A}R, counter agonist-independent binding cooperativity (cooperative folding) was found to occur (Forms 4 and 5). In this way, the scA{sub 2A}R/D{sub 2L}R system has unveiled the cellular phenomenon as a snapshot of the

  5. Paradigmenwechsel in der Anti-Aging-Medizin: Hormesis, Target-of-Rapamycin-Komplex und erste Anti-Aging-Pillen // Paradigm Shift in Anti-Aging Medicine: Hormesis, Target of Rapamycin Complex and First Human Anti-Aging-Pills

    Directory of Open Access Journals (Sweden)

    Römmler A

    2016-01-01

    Full Text Available Studies in model organisms have shown that some drugs and lifestyle practices (calorie-restricted diets, regular exercise, e.g. can extend life and health span and protect against the onset of age-related chronic diseases by targeting physiological pathways.brA common mode of action was found via mTOR (mechanistic Target Of Rapamycin pathway signalling. This intracellular protein kinase complex plays a key role in stimulating anabolic and cell growth promoting processes, while inhibiting autophagy. On the other hand, downregulation results in antiproliferative, anticancer and intensive cell-repairing effects leading to life and health span extension and stress resistance. The mTOR complex regulates such basic cell activities and integrates signals from nutrition sensing, energy metabolism, insulin and growth factors, stress and hypoxia.brImportantly, mTOR can be inhibited by some molecules and their analogs (rapamycin, resveratrol, metformin, e.g., which are released naturally from plants, yeast or bacteria to protect against natural enemies. Its dosage resembles an adaptive hormetic response relationship, as high concentrations are toxic and mild doses are associated with anticancer and antiaging effects. This opens up new avenues for their use as „anti-aging pills“ in humans.brRecent human data suggest that metformin, rapamycin and other mTOR-inhibitors could delay heart disease, cancer, cognitive decline and improve survival time in people with diabetes mellitus. In addition, response to influenca vaccine was enhanced by rapamycin in adults with immunosenescence, indicating beneficial anti-aging effects in the elderly.br“Treat aging” is an actual call to recognize aging as an indication appropriate for clinical trials and treatments, as it was recently approved by the Federal Drug Administration (FDA USA. p bKurzfassung/b: Die ansteigende Morbidität und Invalidität in alternden Industrienationen stößt an die Grenzen der Ressourcen

  6. A systematic review of economic evaluations of Tyrosine Kinase Inhibitors of Vascular Endothelial Growth Factor Receptors, mammalian target of rapamycin inhibitors and Programmed Death-1 inhibitors in metastatic renal cell cancer.

    Science.gov (United States)

    Petrou, Panagiotis

    2018-02-16

    The therapeutic categories of Tyrosine Kinase Inhibitors of Vascular Endothelial Growth Factor Receptors, mammalian target of rapamycin inhibitors and Programmed Death-1 inhibitors have transformed the treatment of metastatic renal cell cancer. Nevertheless, this comes at an increased cost, in tandem with similar fiscal pressures in the broader oncology sector, which may jeopardize the sustainability of health systems. Areas covered To this direction, the economic evaluation of these agents is essential for rational and efficient resource allocation. The aim of this study is to glean, assess and present an outline of the available cost-effectiveness studies of these agents in the management of metastatic renal cell cancer. Expert Commentary We concluded that the results of economic evaluation are pertinent, apart from the product under evaluation, to the country setting as well.

  7. Inhibition of the mammalian target of rapamycin (mTOR in advanced pancreatic cancer: results of two phase II studies

    Directory of Open Access Journals (Sweden)

    Zhang Yujian

    2010-07-01

    Full Text Available Abstract Background The phosphoinositide 3-kinase (PI3K/Akt pathway is constitutively activated in pancreatic cancer and the mammalian target of rapamycin (mTOR kinase is an important mediator for its signaling. Our recent in vitro studies suggest that prolonged exposure of pancreatic cancer cells to mTOR inhibitors can promote insulin receptor substrate-PI3K interactions and paradoxically increase Akt phosphorylation and cyclin D1 expression in pancreatic cancer cells (negative feedback loop. The addition of erlotinib to rapamycin can down-regulate rapamycin-stimulated Akt and results in synergistic antitumor activity with erlotinib in preclinical tumor models. Methods Two studies prospectively enrolled adult patients with advanced pancreatic cancer, Eastern Cooperative Oncology Group performance status 0-1, adequate hematologic, hepatic and renal parameters and measurable disease. In Study A, temsirolimus was administered intravenously at 25 mg weekly. In Study B, everolimus was administered orally at 30 mg weekly and erlotinib was administered at 150 mg daily. The primary endpoint in both studies was overall survival at 6 months. Secondary endpoints included time to progression, progression-free survival, overall survival, response rate, safety and toxicity. Pretreatment tumor biopsies were analyzed by immunofluorescence and laser scanning cytometry for the expression of pmTOR/mTOR, pAkt/Akt, pErk/Erk, pS6, p4EBP-1 and PTEN. Results Five patients enrolled in Study A; Two patients died within a month (rapid disease progression and hemorrhagic stroke, respectively. One patient developed dehydration and another developed asthenia. Sixteen patients enrolled in Study B.: 12 males, all ECOG PS = 1. Median cycles = 1 (range 1-2. Grade 4 toxicity: hyponatremia (n = 1, Grade 3: diarrhea (n = 1, cholangitis (n = 3, hyperglycemia (n = 1, fatigue (n = 1. Grade 2: pneumonia (n = 2, dehydration (n = 2, nausea (n = 2, neutropenia (n = 1, mucositis (n = 2

  8. Inhibitory effect of rapamycin and dexamethasone on production of IL-17 and IFN-gamma in Vogt-Koyanagi-Harada patients

    NARCIS (Netherlands)

    Yang, K.; Wen, J.; Liu, X.; Kijlstra, A.; Chen, L.; Chi, W.; Zhou, H.; Huang, X.; Yang, P.

    2009-01-01

    Aims: To evaluate the effect of rapamycin (RAPA) and dexamethasone (DEX) on the production of IL-17 and IFN-gamma by peripheral blood mononuclear cells (PBMCs) from Vogt-Koyanagi-Harada (VKH) patients and healthy individuals. Methods: Blood samples were drawn from 10 active VKH patients and 10

  9. Effect assessment of subconjunctival injection of rapamycin-loaded microspheres in non-obese diabetic mice with dry eye caused by Sjögren's syndrome

    Directory of Open Access Journals (Sweden)

    Meng Wang

    2013-05-01

    Full Text Available AIM: To study the effect of rapamycin-loaded microspheres in non-obese diabetic(NODmice with dry eye caused by Sjögren's syndrome(SS. METHODS: Twenty 8-week-old female NOD mice with dry eye caused by SS were randomly divided into 4 groups. One week later, the mice were treated with subconjunctival injection. GroupⅠ and Ⅱ received 200μg/kg and 400μg/kg rapamycin-loaded microspheres, Group Ⅲ and Ⅳ received normal saline and empty microspheres. Five 8-week-old female healthy KM mice were used as untreated controls. Before and 5, 10, 15, 20 days after the experiment, the amount of secretion of tears, the score of corneal fluorescein staining and rose bengal staining were investigated. Conjunctival epithelial cells were observed and graded by conjunctival impression cytology. RESULTS: Compared with the group Ⅲ and Ⅳ, the amount of secretion of tears of the mice in groupⅠ and Ⅱ increased. The scores of corneal fluorescein staining and rose bengal staining were lower. The levels of conjunctival impression cytology reduced. CONCLUSION: Rapamycin-loaded microspheres can decrease dry eye signs by alleviating the ocular surface inflammation of NOD mice. It suggests rapamycin-loaded microsphere is valuable to dry eye caused by SS.

  10. The post-therapeutic effect of rapamycin in mild traumatic brain-injured rats ensuing in the upregulation of autophagy and mitophagy.

    Science.gov (United States)

    Wang, Changxing; Hu, Zhiying; Zou, Yang; Xiang, Mingjun; Jiang, Yuting; Botchway, Benson O A; Huo, Xue; Du, Xiaoxue; Fang, Marong

    2017-09-01

    Mild traumatic brain injury (mTBI), common in juveniles, has been reported to be caused by sports-related concussion. Many young children may suffer from post-concussion syndrome. mTBI, in early stages of life, could play a part in neuron apoptosis and degeneration, cognitive and motor coordination impairment, as well as dementia. Our study was aimed at further investigating the post-therapeutic efficacy of rapamycin in the recuperation of mTBI while at the same time investigating the metamorphosis in both autophagy and mitophagy in mTBI. We created a weight-drop rat mTBI model with the administration of rapamycin at 4 h after every mTBI. Behavioral tests of beam walking and open field task indicated the expected improvement of cognitive and motor coordination functions. Both Western blot and immunofluorescence examinations revealed increased Beclin-1 and PINK1 in the treated rats as well as reduction of caspase-3 and cytochrome C (Cyt C). More so, the TUNEL staining evidenced curtailment of apoptotic cells following treatment with rapamycin. The upregulation of Beclin-1 and PINK1 and the downregulation of caspase-3 and Cyt C extrapolate that rapamycin plays neuroprotective as well as anti-apoptotic role via interposition of both autophagy and mitophagy. © 2017 International Federation for Cell Biology.

  11. Activation of the Mammalian Target of Rapamycin in the Rostral Ventromedial Medulla Contributes to the Maintenance of Nerve Injury-Induced Neuropathic Pain in Rat

    Directory of Open Access Journals (Sweden)

    Jian Wang

    2015-01-01

    Full Text Available The mammalian target of rapamycin (mTOR, a serine-threonine protein kinase, integrates extracellular signals, thereby modulating several physiological and pathological processes, including pain. Previous studies have suggested that rapamycin (an mTOR inhibitor can attenuate nociceptive behaviors in many pain models, most likely at the spinal cord level. However, the mechanisms of mTOR at the supraspinal level, particularly at the level of the rostral ventromedial medulla (RVM, remain unclear. Thus, the aim of this study was to elucidate the role of mTOR in the RVM, a key relay region for the descending pain control pathway, under neuropathic pain conditions. Phosphorylated mTOR was mainly expressed in serotonergic spinally projecting neurons and was significantly increased in the RVM after spared nerve injury- (SNI- induced neuropathic pain. Moreover, in SNI rat brain slices, rapamycin infusion both decreased the amplitude instead of the frequency of spontaneous excitatory postsynaptic currents and reduced the numbers of action potentials in serotonergic neurons. Finally, intra-RVM microinjection of rapamycin effectively alleviated established mechanical allodynia but failed to affect the development of neuropathic pain. In conclusion, our data provide strong evidence for the role of mTOR in the RVM in nerve injury-induced neuropathic pain, indicating a novel mechanism of mTOR inhibitor-induced analgesia.

  12. Sustained activation of the mammalian target of rapamycin nutrient sensing pathway is associated with hepatic insulin resistance, but not with steatosis, in mice

    NARCIS (Netherlands)

    Korsheninnikova, E.; van der Zon, G. C. M.; Voshol, P. J.; Janssen, G. M.; Havekes, L. M.; Grefhorst, A.; Kuipers, F.; Reijngoud, D. -J.; Romijn, J. A.; Ouwens, D. M.; Maassen, J. A.

    2006-01-01

    Aims/hypothesis Activation of nutrient sensing through mammalian target of rapamycin (mTOR) has been linked to the pathogenesis of insulin resistance. We examined activation of mTOR-signalling in relation to insulin resistance and hepatic steatosis in mice. Materials and methods Chronic hepatic

  13. Synergistic inhibition of human melanoma proliferation by combination treatment with B-Raf inhibitor BAY43-9006 and mTOR inhibitor Rapamycin

    Directory of Open Access Journals (Sweden)

    Slingluff Craig L

    2005-10-01

    Full Text Available Abstract Background Targeted inhibition of protein kinases is now acknowledged as an effective approach for cancer therapy. However, targeted therapies probably have limited success because cancer cells have alternate pathways for survival and proliferation thereby avoiding inhibition. We tested the hypothesis that combination of targeted agents would be more effective than single agents in arresting melanoma cell proliferation. Methods We evaluated whether BAY43-9006, an inhibitor of the B-Raf kinase, and rapamycin, an inhibitor of the mTOR kinase, would inhibit serum-stimulated proliferation of human melanoma cell lines, either alone or in combination. Proliferation was measured by quantitating melanoma cell numbers with a luciferase for ATP. Phosphorylation of proteins downstream of targeted kinase(s was assayed by immunoblots. Statistical significance was determined with the Student-T test. Isobologram analysis was performed to distinguish additive versus synergistic effects of combinations of drugs. Results Serum-stimulated proliferation of multiple human melanoma cell lines was inhibited by BAY43-9006 and by rapamycin. Melanoma cells containing the B-Raf mutation V599E were more sensitive than cells with wild-type B-raf to 10 nM doses of both BAY43-9006 and rapamycin. Regardless of B-Raf mutational status, the combination of low dose rapamycin and BAY43-9006 synergistically inhibited melanoma cell proliferation. As expected, rapamycin inhibited the phosphorylation of mTOR substrates, p70S6K and 4EBP1, and BAY43-9006 inhibited phosphorylation of ERK, which is dependent on B-Raf activity. We also observed unexpected rapamycin inhibition of the phosphorylation of ERK, as well as BAY43-9006 inhibition of the phosphorylation of mTOR substrates, p70S6K and 4EBP1. Conclusion There was synergistic inhibition of melanoma cell proliferation by the combination of rapamycin and BAY 43-9006, and unexpected inhibition of two signaling pathways by agents

  14. Discovery of GSK2126458, a Highly Potent Inhibitor of PI3K and the Mammalian Target of Rapamycin

    Energy Technology Data Exchange (ETDEWEB)

    Knight, Steven D.; Adams, Nicholas D.; Burgess, Joelle L.; Chaudhari, Amita M.; Darcy, Michael G.; Donatelli, Carla A.; Luengo, Juan I.; Newlander, Ken A.; Parrish, Cynthia A.; Ridgers, Lance H.; Sarpong, Martha A.; Schmidt, Stanley J.; Aller, Glenn S.Van; Carson, Jeffrey D.; Diamond, Melody A.; Elkins, Patricia A.; Gardiner, Christine M.; Garver, Eric; Gilbert, Seth A.; Gontarek, Richard R.; Jackson, Jeffrey R.; Kershner, Kevin L.; Luo, Lusong; Raha, Kaushik; Sherk, Christian S.; Sung, Chiu-Mei; Sutton, David; Tummino, Peter J.; Wegrzyn, Ronald J.; Auger, Kurt R.; Dhanak, Dashyant (GSKPA)

    2010-09-30

    Phosphoinositide 3-kinase {alpha} (PI3K{alpha}) is a critical regulator of cell growth and transformation, and its signaling pathway is the most commonly mutated pathway in human cancers. The mammalian target of rapamycin (mTOR), a class IV PI3K protein kinase, is also a central regulator of cell growth, and mTOR inhibitors are believed to augment the antiproliferative efficacy of PI3K/AKT pathway inhibition. 2,4-Difluoro-N-{l_brace}2-(methyloxy)-5-[4-(4-pyridazinyl)-6-quinolinyl]-3-pyridinyl{r_brace}benzenesulfonamide (GSK2126458, 1) has been identified as a highly potent, orally bioavailable inhibitor of PI3K{alpha} and mTOR with in vivo activity in both pharmacodynamic and tumor growth efficacy models. Compound 1 is currently being evaluated in human clinical trials for the treatment of cancer.

  15. Inhibition of Mammalian Target of Rapamycin Complex 1 Attenuates Salt-Induced Hypertension and Kidney Injury in Dahl Salt-Sensitive Rats.

    Science.gov (United States)

    Kumar, Vikash; Wollner, Clayton; Kurth, Theresa; Bukowy, John D; Cowley, Allen W

    2017-10-01

    The goal of the present study was to explore the protective effects of mTORC1 (mammalian target of rapamycin complex 1) inhibition by rapamycin on salt-induced hypertension and kidney injury in Dahl salt-sensitive (SS) rats. We have previously demonstrated that H 2 O 2 is elevated in the kidneys of SS rats. The present study showed a significant upregulation of renal mTORC1 activity in the SS rats fed a 4.0% NaCl for 3 days. In addition, renal interstitial infusion of H 2 O 2 into salt-resistant Sprague Dawley rats for 3 days was also found to stimulate mTORC1 activity independent of a rise of arterial blood pressure. Together, these data indicate that the salt-induced increases of renal H 2 O 2 in SS rats activated the mTORC1 pathway. Daily administration of rapamycin (IP, 1.5 mg/kg per day) for 21 days reduced salt-induced hypertension from 176.0±9.0 to 153.0±12.0 mm Hg in SS rats but had no effect on blood pressure salt sensitivity in Sprague Dawley treated rats. Compared with vehicle, rapamycin reduced albumin excretion rate in SS rats from 190.0±35.0 to 37.0±5.0 mg/d and reduced the renal infiltration of T lymphocytes (CD3 + ) and macrophages (ED1 + ) in the cortex and medulla. Renal hypertrophy and cell proliferation were also reduced in rapamycin-treated SS rats. We conclude that enhancement of intrarenal H 2 O 2 with a 4.0% NaCl diet stimulates the mTORC1 pathway that is necessary for the full development of the salt-induced hypertension and kidney injury in the SS rat. © 2017 American Heart Association, Inc.

  16. Different patterns of Akt and ERK feedback activation in response to rapamycin, active-site mTOR inhibitors and metformin in pancreatic cancer cells.

    Science.gov (United States)

    Soares, Heloisa P; Ni, Yang; Kisfalvi, Krisztina; Sinnett-Smith, James; Rozengurt, Enrique

    2013-01-01

    The mTOR pathway is aberrantly stimulated in many cancer cells, including pancreatic ductal adenocarcinoma (PDAC), and thus it is a potential target for therapy. However, the mTORC1/S6K axis also mediates negative feedback loops that attenuate signaling via insulin/IGF receptor and other tyrosine kinase receptors. Suppression of these feed-back loops unleashes over-activation of upstream pathways that potentially counterbalance the antiproliferative effects of mTOR inhibitors. Here, we demonstrate that treatment of PANC-1 or MiaPaCa-2 pancreatic cancer cells with either rapamycin or active-site mTOR inhibitors suppressed S6K and S6 phosphorylation induced by insulin and the GPCR agonist neurotensin. Rapamycin caused a striking increase in Akt phosphorylation at Ser(473) while the active-site inhibitors of mTOR (KU63794 and PP242) completely abrogated Akt phosphorylation at this site. Conversely, active-site inhibitors of mTOR cause a marked increase in ERK activation whereas rapamycin did not have any stimulatory effect on ERK activation. The results imply that first and second generation of mTOR inhibitors promote over-activation of different pro-oncogenic pathways in PDAC cells, suggesting that suppression of feed-back loops should be a major consideration in the use of these inhibitors for PDAC therapy. In contrast, metformin abolished mTORC1 activation without over-stimulating Akt phosphorylation on Ser(473) and prevented mitogen-stimulated ERK activation in PDAC cells. Metformin induced a more pronounced inhibition of proliferation than either KU63794 or rapamycin while, the active-site mTOR inhibitor was more effective than rapamycin. Thus, the effects of metformin on Akt and ERK activation are strikingly different from allosteric or active-site mTOR inhibitors in PDAC cells, though all these agents potently inhibited the mTORC1/S6K axis.

  17. FK506 Binding Protein Mediates Glioma Cell Growth and Sensitivity to Rapamycin Treatment by Regulating NF-κB Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Wei Jiang

    2008-03-01

    Full Text Available FK506 binding protein 5 (FKBP5 belongs to a family of immunophilins named for their ability to bind immunosuppressive drugs, also known as peptidyl-prolyl cis-trans isomerases, and also with chaperones to help protein folding. Using glioma cDNA microarray analysis, we found that FKBP5 was overexpressed in glioma tumors. This finding was further validated by real-time reverse transcription-polymerase chain reaction and Western blot analysis. The roles of FKBP5 in glioma cells were then examined. We found that cell growth was suppressed after FKBP5 expression was inhibited by short interfering RNA transfection and enhanced by FKBP5 overexpression. Electrophoretic mobility shift assay showed that nuclear factor-kappa B (NF-κB and DNA binding was enhanced by FKBP5 overexpression. The expression level of I-kappa B alpha and phosphorylated NF-κB was regulated by the expression of FKBP5. These data suggest that FKBP5 is involved in NF-κB pathway activation in glioma cells. In addition, FKBP5 overexpression in rapamycin-sensitive U87 cells blocked the cells' response to rapamycin treatment, whereas rapamycin-resistant glioma cells, both PTEN-positive and -negative, were synergistically sensitive to rapamycin after FKBP5 was knocked down, suggesting that the FKBP5 regulates glioma cell response to rapamycin treatment. In conclusion, our study demonstrates that FKBP5 plays an important role in glioma growth and chemoresistance through regulating signal transduction of the NF-κB pathway.

  18. Drosophila larvae lacking the bcl-2 gene, buffy, are sensitive to nutrient stress, maintain increased basal target of rapamycin (Tor signaling and exhibit characteristics of altered basal energy metabolism

    Directory of Open Access Journals (Sweden)

    Monserrate Jessica P

    2012-07-01

    Full Text Available Abstract Background B cell lymphoma 2 (Bcl-2 proteins are the central regulators of apoptosis. The two bcl-2 genes in Drosophila modulate the response to stress-induced cell death, but not developmental cell death. Because null mutants are viable, Drosophila provides an optimum model system to investigate alternate functions of Bcl-2 proteins. In this report, we explore the role of one bcl-2 gene in nutrient stress responses. Results We report that starvation of Drosophila larvae lacking the bcl-2 gene, buffy, decreases survival rate by more than twofold relative to wild-type larvae. The buffy null mutant reacted to starvation with the expected responses such as inhibition of target of rapamycin (Tor signaling, autophagy initiation and mobilization of stored lipids. However, the autophagic response to starvation initiated faster in larvae lacking buffy and was inhibited by ectopic buffy. We demonstrate that unusually high basal Tor signaling, indicated by more phosphorylated S6K, was detected in the buffy mutant and that removal of a genomic copy of S6K, but not inactivation of Tor by rapamycin, reverted the precocious autophagy phenotype. Instead, Tor inactivation also required loss of a positive nutrient signal to trigger autophagy and loss of both was sufficient to activate autophagy in the buffy mutant even in the presence of enforced phosphoinositide 3-kinase (PI3K signaling. Prior to starvation, the fed buffy mutant stored less lipid and glycogen, had high lactate levels and maintained a reduced pool of cellular ATP. These observations, together with the inability of buffy mutant larvae to adapt to nutrient restriction, indicate altered energy metabolism in the absence of buffy. Conclusions All animals in their natural habitats are faced with periods of reduced nutrient availability. This study demonstrates that buffy is required for adaptation to both starvation and nutrient restriction. Thus, Buffy is a Bcl-2 protein that plays an

  19. Phosphate (Pi)-regulated heterodimerization of the high-affinity sodium-dependent Pi transporters PiT1/Slc20a1 and PiT2/Slc20a2 underlies extracellular Pi sensing independently of Pi uptake.

    Science.gov (United States)

    Bon, Nina; Couasnay, Greig; Bourgine, Annabelle; Sourice, Sophie; Beck-Cormier, Sarah; Guicheux, Jérôme; Beck, Laurent

    2017-12-12

    Extracellular phosphate (Pi) can act as a signaling molecule that directly alters gene expression and cellular physiology. The ability of cells or organisms to detect changes in extracellular Pi levels implies the existence of a Pi-sensing mechanism that signals to the body or individual cell. However, unlike in prokaryotes, yeasts, and plants, the molecular players involved in Pi sensing in mammals remain unknown. In this study, we investigated the involvement of the high-affinity, Na-dependent Pi transporters PiT1 and PiT2 in mediating Pi signaling in skeletal cells. We found that deletion of PiT1 or PiT2 blunted the Pi-dependent MAPK ERK1/2-mediated phosphorylation, and subsequent gene upregulation of the mineralization inhibitors matrix Gla protein and osteopontin. This result suggested that both PiTs are necessary for Pi signaling. Moreover, the MAPK ERK1/2 phosphorylation could be rescued by overexpressing Pi transport-deficient PiT mutants. Using crosslinking and bioluminescence resonance energy transfer (BRET) approaches, we found that PiT1 and PiT2 form high-abundance homodimers and Pi-regulated low-abundance heterodimers. Interestingly, in the absence of Na-dependent Pi transport activity, the PiT1-PiT2 heterodimerization was still regulated by extracellular Pi levels. Of note, when two putative Pi-binding residues, Ser-128 (in PiT1) and Ser-113 (in PiT2), were substituted with alanine, the PiT1-PiT2 heterodimerization was no longer regulated by extracellular Pi. These observations suggested that Pi binding rather than Pi uptake may be the key factor in mediating Pi signaling through the PiT proteins. Taken together, these results demonstrate that Pi-regulated PiT1/PiT2 heterodimerization mediates Pi sensing independently of Pi uptake. Copyright © 2017, The American Society for Biochemistry and Molecular Biology.

  20. Combination of rapamycin, CI-1040, and 17-AAG inhibits metastatic capacity of prostate cancer via Slug inhibition.

    Directory of Open Access Journals (Sweden)

    Guanxiong Ding

    Full Text Available Though prostate cancer (PCa has slow progression, the hormone refractory (HRCP and metastatic entities are substantially lethal and lack effective treatments. Transcription factor Slug is critical in regulating metastases of various tumors including PCa. Here we studied targeted therapy against Slug using combination of 3 drugs targeting 3 pathways respectively converging via Slug and further regulating PCa metastasis. Using in vitro assays we confirmed that Slug up-regulation incurred inhibition of E-cadherin that was anti-metastatic, and inhibited Bim-regulated cell apoptosis in PCa. Upstream PTEN/Akt, mTOR, Erk, and AR/Hsp90 pathways were responsible for Slug up-regulation and each of these could be targeted by rapamycin, CI-1040, and 17-AAG respectively. In 4 PCa cell lines with different traits in terms of PTEN loss and androgen sensitivity we tested the efficacy of mono- and combined therapy with the drugs. We found that metastatic capacity of the cells was maximally inhibited only when all 3 drugs were combined, due to the crosstalk between the pathways. 17-AAG decreases Slug expression via blockade of HSP90-dependent AR stability. Combination of rapamycin and CI-1040 diminishes invasiveness more potently in PCa cells that are androgen insensitive and with PTEN loss. Slug inhibited Bim-mediated apoptosis that could be rescued by mTOR/Erk/HSP90 inhibitors. Using mouse models for circulating PCa DNA quantification, we found that combination of mTOR/Erk/HSP90 inhibitors reduced circulating PCa cells in vivo significantly more potently than combination of 2 or monotherapy. Conclusively, combination of mTOR/Erk/Hsp90 inhibits metastatic capacity of prostate cancer via Slug inhibition.

  1. Induction of biogenic magnetization and redox control by a component of the target of rapamycin complex 1 signaling pathway.

    Directory of Open Access Journals (Sweden)

    Keiji Nishida

    Full Text Available Most organisms are simply diamagnetic, while magnetotactic bacteria and migratory animals are among organisms that exploit magnetism. Biogenic magnetization not only is of fundamental interest, but also has industrial potential. However, the key factor(s that enable biogenic magnetization in coordination with other cellular functions and metabolism remain unknown. To address the requirements for induction and the application of synthetic bio-magnetism, we explored the creation of magnetism in a simple model organism. Cell magnetization was first observed by attraction towards a magnet when normally diamagnetic yeast Saccharomyces cerevisiae were grown with ferric citrate. The magnetization was further enhanced by genetic modification of iron homeostasis and introduction of ferritin. The acquired magnetizable properties enabled the cells to be attracted to a magnet, and be trapped by a magnetic column. Superconducting quantum interference device (SQUID magnetometry confirmed and quantitatively characterized the acquired paramagnetism. Electron microscopy and energy-dispersive X-ray spectroscopy showed electron-dense iron-containing aggregates within the magnetized cells. Magnetization-based screening of gene knockouts identified Tco89p, a component of TORC1 (Target of rapamycin complex 1, as important for magnetization; loss of TCO89 and treatment with rapamycin reduced magnetization in a TCO89-dependent manner. The TCO89 expression level positively correlated with magnetization, enabling inducible magnetization. Several carbon metabolism genes were also shown to affect magnetization. Redox mediators indicated that TCO89 alters the intracellular redox to an oxidized state in a dose-dependent manner. Taken together, we demonstrated that synthetic induction of magnetization is possible and that the key factors are local redox control through carbon metabolism and iron supply.

  2. The Triangle of Death in Alzheimer's Disease Brain: The Aberrant Cross-Talk Among Energy Metabolism, Mammalian Target of Rapamycin Signaling, and Protein Homeostasis Revealed by Redox Proteomics.

    Science.gov (United States)

    Di Domenico, Fabio; Barone, Eugenio; Perluigi, Marzia; Butterfield, D Allan

    2017-03-10

    Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder and represents one of the most disabling conditions. AD shares many features in common with systemic insulin resistance diseases, suggesting that it can be considered as a metabolic disease, characterized by reduced insulin-stimulated growth and survival signaling, increased oxidative stress (OS), proinflammatory cytokine activation, mitochondrial dysfunction, impaired energy metabolism, and altered protein homeostasis. Recent Advances: Reduced glucose utilization and energy metabolism in AD have been associated with the buildup of amyloid-β peptide and hyperphosphorylated tau, increased OS, and the accumulation of unfolded/misfolded proteins. Mammalian target of rapamycin (mTOR), which is aberrantly activated in AD since early stages, plays a key role during AD neurodegeneration by, on one side, inhibiting insulin signaling as a negative feedback mechanism and, on the other side, regulating protein homeostasis (synthesis/clearance). It is likely that the concomitant and mutual alterations of energy metabolism-mTOR signaling-protein homeostasis might represent a self-sustaining triangle of harmful events that trigger the degeneration and death of neurons and the development and progression of AD. Intriguingly, the altered cross-talk between the components of such a triangle of death, beyond altering the redox homeostasis of the neuron, is further exacerbated by increased levels of OS that target and impair key components of the pathways involved. Redox proteomic studies in human samples and animal models of AD-like dementia led to identification of oxidatively modified components of the pathways composing the triangle of death, therefore revealing the crucial role of OS in fueling this aberrant vicious cycle. The identification of compounds able to restore the function of the pathways targeted by oxidative damage might represent a valuable therapeutic approach to slow or delay AD. Antioxid

  3. Rapamycin inhibits CaCl2-induced thoracic aortic aneurysm formation in rats through mTOR-mediated suppression of proinflammatory mediators.

    Science.gov (United States)

    Cao, Jiumei; Wu, Qihong; Geng, Liang; Chen, Xiaonan; Shen, Weifeng; Wu, Fang; Chen, Ying

    2017-08-01

    The aim of the present study was to investigate the effect of the mammalian target of rapamycin (mTOR) signaling pathway on thoracic aortic aneurysm (TAA) development. The study used a calcium chloride (CaCl2)‑induced rat TAA model to explore the potential role of mTOR signaling pathway in the disease development. Adult male Sprague‑Dawley rats underwent the periarterial exposure of thoracic aorta to either 0.5 M CaCl2 or normal saline, and a subgroup of CaCl2‑treated rats received rapamycin 1 day prior to surgery. Without pre‑administering rapamycin, significantly enhanced phosphorylation of mTOR and expression of proinflammatory cytokines [i.e., tumor necrosis factor α (TNF‑α), interleukin 6 (IL‑6), and interleukin (IL)‑1β] were observed in the CaCl2‑treated aortic segments 2 days post‑treatment compared with the NaCl‑treated segments. At 2 weeks post‑treatment, hematoxylin and eosin and Verhoeff‑Van Gieson staining revealed aneurysmal alteration and disappearance of normal wavy elastic structures in the aortic segments exposed to CaCl2. In contrast, the CaCl2‑induced TAA formation was inhibited by pre‑administering rapamycin to CaCl2‑treated rats, which demonstrated attenuated mTOR phosphorylation and downregulation of the proinflammatory mediators (i.e., TNF‑α, IL‑6, IL‑1β, matrix metallopeptidases 2 and 9) to the control level. Further in vitro cell culture experiments using aortic smooth muscle cell (SMC) suggested that the inhibition of the mTOR signaling pathway by rapamycin could promote the differentiation of SMCs, as reflected by the reduced expression of S100A4 and osteopontin. The present study indicated that the early enhanced mTOR signaling pathway in the TAA development and mTOR inhibitor rapamycin may inhibit CaCl2‑induced TAA formation.

  4. Mammalian Target of Rapamycin Inhibition in Trypanosoma cruzi-Infected Macrophages Leads to an Intracellular Profile That Is Detrimental for Infection

    Directory of Open Access Journals (Sweden)

    Jorge David Rojas Márquez

    2018-02-01

    Full Text Available The causative agent of Chagas’ disease, Trypanosoma cruzi, affects approximately 10 million people living mainly in Latin America, with macrophages being one of the first cellular actors confronting the invasion during T. cruzi infection and their function depending on their proper activation and polarization into distinct M1 and M2 subtypes. Macrophage polarization is thought to be regulated not only by cytokines and growth factors but also by environmental signals. The metabolic checkpoint kinase mammalian target of rapamycin (mTOR-mediated sensing of environmental and metabolic cues influences macrophage polarization in a complex and as of yet incompletely understood manner. Here, we studied the role of the mTOR pathway in macrophages during T. cruzi infection. We demonstrated that the parasite activated mTOR, which was beneficial for its replication since inhibition of mTOR in macrophages by different inhibitors decreased parasite replication. Moreover, in rapamycin pretreated and infected macrophages, we observed a decreased arginase activity and expression, reduced IL-10 and increased interleukin-12 production, compared to control infected macrophages treated with DMSO. Surprisingly, we also found a reduced iNOS activity and expression in these macrophages. Therefore, we investigated possible alternative mechanisms involved in controlling parasite replication in rapamycin pretreated and infected macrophages. Although, cytoplasmic ROS and the enzyme indoleamine 2, 3-dioxygenase (IDO were not involved, we observed a significant increase in IL-6, TNF-α, and IL-1β production. Taking into account that IL-1β is produced by activation of the cytoplasmic receptor NLRP3, which is one of the main components of the inflammasome, we evaluated NLRP3 expression during mTOR inhibition and T. cruzi infection. We observed that rapamycin-pretreated and infected macrophages showed a significant increase in NLRP3 expression and produced higher levels of

  5. Testing intravitreal toxicity of rapamycin in rabbit eyes Toxicidade intravítrea da rapamicina em olhos de coelhos

    Directory of Open Access Journals (Sweden)

    Roberta Pereira de Almeida Manzano

    2009-02-01

    Full Text Available PURPOSE: To evaluate retinal toxicity of varying doses of rapamycin when injected intravitreally in rabbits. Rapamycin is a potent immunosuppressive agent with significant antitumor and antiangiogenic properties, clinically approved for prevention of organ transplant rejection. METHODS: Twelve New Zealand albino rabbits were divided into four groups. Four different doses of rapamycin were prepared in 0.1 ml: 20 µg, 50 µg, 200 µg, and 1000 µg. Each concentration was injected in one eye of three rabbits, and 0.1 ml volume of sterile BSS was injected into the contralateral eye of the three rabbits. Slit-lamp and fundoscopic examinations were performed and the animals were observed for 2 weeks for signs of infection, inflammation, and toxicity. A baseline ERG was performed before drug treatment and at day 14, after which the rabbits were euthanized. Histology of the enucleated eyes was studied to look for retinal toxicity. RESULTS: ERG results showed some decrease in scotopic response; however this was not dose related. ERG results were normal at 20 µg. Histological results showed no retinal toxicity in all groups. CONCLUSION: Although ERG changes were identified at dosages between 50-1000 µg, the histology of all groups up to 1000 µg did not show any discernable abnormalities.OBJETIVO: Avaliar a toxicidade da injeção intravítrea de diferentes doses de rapamicina para a retina de coelhos. Rapamicina é uma potente droga imunossupressora aprovada clinicamente para a prevenção da rejeição de transplantes de orgãos. MÉTODOS: Doze coelhos albinos da Nova Zelândia foram usados neste estudo. Foram divididos em quatro grupos. Quatro diferentes doses de rapamicina foram preparadas nas seguintes concentrações: 20 µg, 50 µg, 200 µg, 1000 µg. Foram realizadas injeções intravítreas de 0,1 ml de cada concentração em um olho de três coelhos e 0,1 ml de solução salina foi injetada no olho contralateral de cada coelho. Foram

  6. CX-5461 induces autophagy and inhibits tumor growth via mammalian target of rapamycin-related signaling pathways in osteosarcoma

    Directory of Open Access Journals (Sweden)

    Li L

    2016-09-01

    Full Text Available Leiming Li,1,* Yan Li,2,* Jiansong Zhao,2 Shuli Fan,3 Liguo Wang,1 Xu Li1 1Department of Joint Surgery and Sports Medicine, The First Affiliated Hospital, 2Department of Spine and Joint Surgery, Sheng Jing Hospital, 3Department of Geriatrics, The First Affiliated Hospital, China Medical University, Shenyang, People’s Republic of China *These authors contributed equally to this work Abstract: Osteosarcoma (OS is the most common primary bone tumor, but molecular mechanisms of the disease have not been well understood, and treatment of metastatic OS remains a challenge. Rapid ribosomal RNA synthesis in cancer is transcribed by RNA polymerase I, which results in unbridled cell growth. The recent discovery of CX-5461, a selective RNA polymerase I inhibitor, exerted its inhibitory effect of ribosomal RNA synthesis and antiproliferative potency. Here, we demonstrate that CX-5461 induces G2 arrest in the cell cycle and expression of microtubule-associated protein 1 light chain 3 II isoform in OS cell lines. Autophagic vacuoles could be observed in electron microscopy and 3-methyladenine prevented cell death mediated by CX-5461. Moreover, it significantly augmented phosphorylated AMP-Activated Protein Kinases α (p-AMPK α. (Thr172 expression in U2-OS cells and decreased p-Akt (Ser473 expression in MNNG cells, respectively, which repressed their downstream effector, mammalian target of rapamycin. On the other hand, CX-5461 increased p53 accumulation and messenger RNA level of its target genes, p21, MDM2, and Sestrin1/2 in U2-OS cells. Knockdown of p53 expression markedly impaired cell death as well as the expression of light chain 3-II and p21 induced by CX-5461. It also significantly enhanced doxorubicin-mediated cytotoxic effect in vitro and in vivo together with additive expression of p53, p21, and light chain 3-II in U2-OS cells. Our data indicate that CX-5461 might induce autophagy via mammalian target of rapamycin-associated signaling pathways

  7. Synthesis of the northern sector (C8-C19) of rapamycin via Chan rearrangement and oxidation of an α-acyloxyacetate

    Science.gov (United States)

    Jeffrey, Scott C.

    2009-01-01

    Two routes to the masked tricarbonyl segment of the immunosuppressant rapamycin comprising C8-C19 were explored beginning from D-xylose. The first approach employed a protected form of 2,4,5-trihydroxypentanol to obtain dithiane 43, which failed to react with dimethyl oxalate to give a 1,2,3-tricarbonyl unit corresponding to the northern sector of rapamycin. A second approach employing carboxylic acid 61 derived from 43 utilized base-mediated (Chan) rearrangement of α-acyloxyacetate 62 with trapping of the resultant enediolate as bis silyl ether 63. Epoxidation of this diene afforded masked tri-keto ester 65 which underwent acid-catalyzed methanolysis to produce cyclic ketal 67. PMID:20161171

  8. Ketamine Exhibits Different Neuroanatomical Profile After Mammalian Target of Rapamycin Inhibition in the Prefrontal Cortex: the Role of Inflammation and Oxidative Stress.

    Science.gov (United States)

    Abelaira, Helena M; Réus, Gislaine Z; Ignácio, Zuleide M; Dos Santos, Maria Augusta B; de Moura, Airam B; Matos, Danyela; Demo, Júlia P; da Silva, Júlia B I; Danielski, Lucineia G; Petronilho, Fabricia; Carvalho, André F; Quevedo, João

    2017-09-01

    Studies indicated that mammalian target of rapamycin (mTOR), oxidative stress, and inflammation are involved in the pathophysiology of major depressive disorder (MDD). Ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, has been identified as a novel MDD therapy; however, the antidepressant mechanism is not fully understood. In addition, the effects of ketamine after mTOR inhibition have not been fully investigated. In the present study, we examined the behavioral and biochemical effects of ketamine in the prefrontal cortex (PFC), hippocampus, amygdala, and nucleus accumbens after inhibition of mTOR signaling in the PFC. Male adult Wistar rats received pharmacological mTOR inhibitor, rapamycin (0.2 nmol) or vehicle into the PFC and then a single dose of ketamine (15 mg/kg, i.p.). Immobility was assessed in forced swimming tests, and then oxidative stress parameters and inflammatory markers were evaluated in the brain and periphery. mTOR activation in the PFC was essential to ketamine's antidepressant-like effects. Ketamine increased lipid damage in the PFC, hippocampus, and amygdala. Protein carbonyl was elevated in the PFC, amygdala, and NAc after ketamine administration. Ketamine also increased nitrite/nitrate in the PFC, hippocampus, amygdala, and NAc. Myeloperoxidase activity increased in the hippocampus and NAc after ketamine administration. The activities of superoxide dismutase and catalase were reduced after ketamine administration in all brain areas studied. Inhibition of mTOR signaling pathways by rapamycin in the PFC was required to protect against oxidative stress by reducing damage and increasing antioxidant enzymes. Finally, the TNF-α level was increased in serum by ketamine; however, the rapamycin plus treatment group was not able to block this increase. Activation of mTOR in the PFC is involved in the antidepressant-like effects of ketamine; however, the inhibition of this pathway was able to protect certain brain areas against

  9. Mammalian target of rapamycin/eukaryotic initiation factor 4F pathway regulates follicle growth and development of theca cells in mice.

    Science.gov (United States)

    Zhang, Chao; Liu, Xiao-Ran; Cao, Yong-Chun; Tian, Jin-Ling; Zhen, Di; Luo, Xiao-Fei; Wang, Xin-Mei; Tian, Jian-Hui; Gao, Jian-Ming

    2017-04-01

    The aim of the present study was to clarify the roles of the mammalian target of rapamycin (mTOR) signalling pathway in follicular growth and development of thecal cells. Using in vivo-grown and in vitro-cultured ovaries, histological changes were evaluated using haematoxylin and eosin (HE) staining. Differentially expressed genes (DEGs) from 0 day post partum (d.p.p.) to 8 d.p.p. ovaries were screened by microarray and verified by quantitative real-time polymerase chain reaction. Forty-two DEGs related to cell proliferation and differentiation were screened out, with most DEGs being related to the to mTOR signalling pathway. Then, 3 d.p.p. ovaries were retrieved and used to verify the role of mTOR signalling in follicle and thecal cell development using its activators (Ras homologue enriched in brain (Rheb) and GTP) and inhibitor (rapamycin). The development of follicles and thecal cells was significantly impaired in ovaries cultured in vitro Day 3 to Day 8. In in vitro-cultured ovaries, Rheb and GTP (is 100ngmL-1 Rheb and 500ngmL-1 GTP for 48h) significantly increased follicle diameter, the percentage of primary and secondary follicles and the umber of thecal cells, and upregulated expression of mTOR, phosphorylated eukaryotic translation initiation factor 4E-binding protein 1 (4EBP1), eukaryotic initiation factor (eIF) 4F and cytochrome P450, family 17, subfamily A, polypeptide 1 (CYP17A1). Rapamycin (10nM rapamycin for 24h) had opposite effects to those of Rheb and GTP, and partly abrogated (significant) the effects of Rheb and GTP when added to the culture in combination with these drugs. Thus, mTOR signalling plays an important role in follicle growth and thecal cell development.

  10. Combination testing (Stage 2) of the Anti-IGF-1 receptor antibody IMC-A12 with rapamycin by the pediatric preclinical testing program.

    Science.gov (United States)

    Kolb, E Anders; Gorlick, Richard; Maris, John M; Keir, Stephen T; Morton, Christopher L; Wu, Jianrong; Wozniak, Amy W; Smith, Malcolm A; Houghton, Peter J

    2012-05-01

    IMC-A12, a fully human antibody that blocks ligand binding to the Type 1 insulin-like growth factor receptor, and rapamycin, a selective inhibitor of mTORC1 signaling, have both demonstrated significant antitumor activity against PPTP solid tumor models. Here we have evaluated antitumor activity of each agent individually and in combination against nine tumor models. IMC-A12 was administered twice weekly and rapamycin was administered daily for 5 days per week for a planned 4 weeks. The impact of combining IMC-A12 with rapamycin was evaluated using two measures: (1) the "therapeutic enhancement" measure, and (2) a linear regression model for time-to-event to formally evaluate for sub- and supra-additivity for the combination compared to the agents used alone. Two osteosarcomas, and one Ewing sarcoma of the nine xenografts tested showed therapeutic enhancement. The combination effect was most dramatic for EW-5 for which PD2 responses of short duration were observed for both single agents and a prolonged PR response was observed for the combination. Both OS-2 and OS-9 showed significantly longer times to progression with the combination compared to either of the single agents, although objective response criteria were not met. The combination of IMC-A12 with rapamycin was well tolerated, and induced tumor responses that were superior to either single agent alone in several models. These studies confirm reports using other antibodies that inhibit IGF-1 receptor-mediated signaling that indicate enhanced therapeutic effect for this combination, and extend the range of histotypes to encompass additional tumors expressing IGF-1R where this approach may be effective. Copyright © 2011 Wiley Periodicals, Inc.

  11. Temporary placement of a paclitaxel or rapamycin-eluting stent is effective to reduce stenting induced inflammatory reaction and scaring in benign cardia stricture models.

    Science.gov (United States)

    Wang, Lin; Zhu, Yue-Qi; Cheng, Ying-Sheng; Cui, Wen-Guo; Chen, Ni-Wei

    2014-12-01

    To investigate whether temporary placement of a paclitaxel or rapamycin eluting stent is more effective to reduce stenting induced inflammatory reaction and scaring than a bared stent in benign cardia stricture models. Eighty dog models of stricture were randomly divided into a control group (CG, n=20, no stent insertion), a bare stent group (BSG, n=20), a paclitaxel eluting (Pacl-ESG, n=20) and a rapamycin eluting stent group (Rapa-ESG, n=20), with one-week stent retention. Lower-oesophageal-sphincter pressure (LOSP), 5-minute barium height (5-mBH) and cardia diameter were assessed before, immediately after the procedure, and regularly for 6 months. Five dogs in each group were euthanized for histological examination at each follow-up assessment. Stent insertion was well tolerated, with similar migration rates in three groups. At 6 months, LOSP and 5-mBH improved in Pacl-ESG and Rapa-ESG compared to BSG (pESG and Rapa-ESG (p>0.05). Cardia kept more patency in the Pacl-ESG and Rapa-ESG than in BSG (pESG and Rapa-ESG compared to BSG (pESG and Rapa-ESG (p>0.05). Paclitaxel or rapamycin-eluting stents insertion led to better outcomes than bare stents in benign cardia stricture models.

  12. Mechanistic target of rapamycin (mTOR: a point of convergence in the action of insulin/IGF-1 and G protein-coupled receptor agonists in pancreatic cancer cells

    Directory of Open Access Journals (Sweden)

    Enrique eRozengurt

    2014-09-01

    Full Text Available Pancreatic ductal adenocarcinoma (PDAC, the most common form of pancreatic cancer, is one of the most lethal human diseases. PDAC is now the fourth leading cause of cancer mortality in both men and women and deaths due to PDAC are projected to increase dramatically. Novel targets and agents for chemoprevention are urgently needed and will most likely arise from a more detailed understanding of the signaling mechanisms that stimulate the promotion and progression of sub-malignant cells into pancreatic cancer cells and from the identification of modifiable risk factors for PDAC. Many epidemiological studies have linked obesity and long-standing type 2 diabetes mellitus (T2DM with increased risk and worse clinical outcomes for developing PDAC. These diet-related metabolic disorders are multifaceted but characterized by peripheral insulin resistance, compensatory overproduction of insulin and increased bioavailability of IGF-1. Mounting evidence indicates that the insulin/IGF-1R system plays a critical role in PDAC development and multiple studies support the notion that crosstalk between the insulin receptor and heptahelical G protein-coupled receptor (GPCR signaling systems is an important element in the biological responses elicited by these signaling systems, including cell proliferation. This article highlights the central role of the mechanistic target of rapamycin (mTOR in mediating crosstalk between insulin/IGF-1 and G protein-coupled receptor (GPCR signaling in pancreatic cancer cells and proposes strategies, including the use of metformin, to target this signaling system in PDAC cells.

  13. Targeting the mammalian target of rapamycin pathway with everolimus: implications for the management of metastatic breast cancer.

    Science.gov (United States)

    Ng, Vin Cci; Johnson, Jeremy J; Cuellar, Sandra

    2015-12-01

    The inhibitors of mammalian target of rapamycin (mTOR) have documented antitumor activity via disruption of various signaling pathways leading to impaired cellular growth, proliferation, and survival. In preclinical studies, mTOR inhibitors use in combination with hormonal therapy has shown promising results in overcoming endocrine resistance in breast cancer cells. The role of everolimus in breast cancer was established in the Breast Cancer Trial of Oral Everolimus-2 (BOLERO-2) trial in combination with exemestane for patients with advanced metastatic hormone receptor-positive (HR+) breast cancer, who relapsed after initial hormonal manipulation. The study met its primary endpoint of significant improvement in progression free survival (PFS) with a median time to progression of 6.9 months in the combination group versus 2.8 months in exemestane group. Favorable improvements in PFS were reported across all patient subgroups regardless of age, Eastern Cooperative Oncology Group performance status, number of prior therapies, and presence of visceral metastases. Adverse events were mostly mild to moderate in severity and consistent with the known safety profile of everolimus. Major toxicities reported include stomatitis, non-infectious pneumonitis, and hyperglycemia. The purpose of this review is to discuss the role of everolimus as a valuable component in advanced metastatic breast cancer and delineate current strategies to prevent and manage the most common toxicities associated with this combination regimen. © The Author(s) 2014.

  14. Mechanism of Metformin-dependent Inhibition of Mammalian Target of Rapamycin (mTOR) and Ras Activity in Pancreatic Cancer

    Science.gov (United States)

    Nair, Vijayalekshmi; Sreevalsan, Sandeep; Basha, Riyaz; Abdelrahim, Maen; Abudayyeh, Ala; Rodrigues Hoffman, Aline; Safe, Stephen

    2014-01-01

    The antidiabetic drug metformin exhibits both chemopreventive and chemotherapeutic activity for multiple cancers including pancreatic cancer; however, the underlying mechanism of action of metformin is unclear. A recent study showed that metformin down-regulated specificity protein (Sp) transcription factors (TFs) Sp1, Sp3, and Sp4 in pancreatic cancer cells and tumors, and this was accompanied by down-regulation of several pro-oncogenic Sp-regulated genes. Treatment with metformin or down-regulation of Sp TFs by RNAi also inhibits two major pro-oncogenic pathways in pancreatic cancer cells, namely mammalian target of rapamycin (mTOR) signaling and epidermal growth factor (EGFR)-dependent activation of Ras. Metformin and Sp knockdown by RNAi decreased expression of the insulin-like growth factor-1 receptor (IGF-1R), resulting in inhibition of mTOR signaling. Ras activity was also decreased by metformin and Sp knockdown of EGFR, another Sp-regulated gene. Thus, the antineoplastic activities of metformin in pancreatic cancer are due, in part, to down-regulation of Sp TFs and Sp-regulated IGF-1R and EGFR, which in turn results in inhibition of mTOR and Ras signaling, respectively. PMID:25143389

  15. Up-Regulation of the Excitatory Amino Acid Transporters EAAT1 and EAAT2 by Mammalian Target of Rapamycin

    Directory of Open Access Journals (Sweden)

    Abeer Abousaab

    2016-11-01

    Full Text Available Background: The excitatory amino-acid transporters EAAT1 and EAAT2 clear glutamate from the synaptic cleft and thus terminate neuronal excitation. The carriers are subject to regulation by various kinases. The EAAT3 isoform is regulated by mammalian target of rapamycin (mTOR. The present study thus explored whether mTOR influences transport by EAAT1 and/or EAAT2. Methods: cRNA encoding wild type EAAT1 (SLC1A3 or EAAT2 (SLC1A2 was injected into Xenopus oocytes without or with additional injection of cRNA encoding mTOR. Dual electrode voltage clamp was performed in order to determine electrogenic glutamate transport (IEAAT. EAAT2 protein abundance was determined utilizing chemiluminescence. Results: Appreciable IEAAT was observed in EAAT1 or EAAT2 expressing but not in water injected oocytes. IEAAT was significantly increased by coexpression of mTOR. Coexpression of mTOR increased significantly the maximal IEAAT in EAAT1 or EAAT2 expressing oocytes, without significantly modifying affinity of the carriers. Moreover, coexpression of mTOR increased significantly EAAT2 protein abundance in the cell membrane. Conclusions: The kinase mTOR up-regulates the excitatory amino acid transporters EAAT1 and EAAT2.

  16. Stable Isotope Labeling Reveals Novel Insights Into Ubiquitin-Mediated Protein Aggregation With Age, Calorie Restriction, and Rapamycin Treatment.

    Science.gov (United States)

    Basisty, Nathan B; Liu, Yuxin; Reynolds, Jason; Karunadharma, Pabalu P; Dai, Dao-Fu; Fredrickson, Jeanne; Beyer, Richard P; MacCoss, Michael J; Rabinovitch, Peter S

    2017-08-18

    Accumulation of protein aggregates with age was first described in aged human tissue over 150 years ago and has since been described in virtually every human tissue. Ubiquitin modifications are a canonical marker of insoluble protein aggregates; however, the composition of most age-related inclusions remains relatively unknown. To examine the landscape of age-related protein aggregation in vivo, we performed an antibody-based pulldown of ubiquitinated proteins coupled with metabolic labeling and mass spectrometry on young and old mice on calorie restriction (CR), rapamycin (RP)-supplemented, and control diets. We show increased abundance of many ubiquitinated proteins in old mice and greater retention of preexisting (unlabeled) ubiquitinated proteins relative to their unmodified counterparts-fitting the expected profile of age-increased accumulation of long-lived aggregating proteins. Both CR and RP profoundly affected ubiquitinome composition, half-live, and the insolubility of proteins, consistent with their ability to mobilize these age-associated accumulations. Finally, confocal microscopy confirmed the aggregation of two of the top predicted aggregating proteins, keratins 8/18 and catalase, as well as their attenuation by CR and RP. Stable-isotope labeling is a powerful tool to gain novel insights into proteostasis mechanisms, including protein aggregation, and could be used to identify novel therapeutic targets in aging and protein aggregation diseases. © The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. The Mammalian Target of Rapamycin and DNA methyltransferase 1 axis mediates vascular endothelial dysfunction in response to disturbed flow.

    Science.gov (United States)

    Zhang, Yun-Peng; Huang, Yi-Tao; Huang, Tse-Shun; Pang, Wei; Zhu, Juan-Juan; Liu, Yue-Feng; Tang, Run-Ze; Zhao, Chuan-Rong; Yao, Wei-Juan; Li, Yi-Shuan; Chien, Shu; Zhou, Jing

    2017-11-08

    The earliest atherosclerotic lesions preferentially develop in arterial regions experienced disturbed blood flow, which induces endothelial expression of pro-atherogenic genes and the subsequent endothelial dysfunction. Our previous study has demonstrated an up-regulation of DNA methyltransferase 1 (DNMT1) and a global hypermethylation in vascular endothelium subjected to disturbed flow. Here, we determined that DNMT1-specific inhibition in arterial wall ameliorates the disturbed flow-induced atherosclerosis through, at least in part, targeting cell cycle regulator cyclin A and connective tissue growth factor (CTGF). We identified the signaling pathways mediating the flow-induction of DNMT1. Inhibition of the mammalian target of rapamycin (mTOR) suppressed the DNMT1 up-regulation both in vitro and in vivo. Together, our results demonstrate that disturbed flow influences endothelial function and induces atherosclerosis in an mTOR/DNMT1-dependent manner. The conclusions obtained from this study might facilitate further evaluation of the epigenetic regulation of endothelial function during the pathological development of atherosclerosis and offer novel prevention and therapeutic targets of this disease.

  18. Tramadol Pretreatment Enhances Ketamine-Induced Antidepressant Effects and Increases Mammalian Target of Rapamycin in Rat Hippocampus and Prefrontal Cortex

    Directory of Open Access Journals (Sweden)

    Chun Yang

    2012-01-01

    Full Text Available Several lines of evidence have demonstrated that acute administration of ketamine elicits fast-acting antidepressant effects. Moreover, tramadol also has potential antidepressant effects. The aim of this study was to investigate the effects of pretreatment with tramadol on ketamine-induced antidepressant activity and was to determine the expression of mammalian target of rapamycin (mTOR in rat hippocampus and prefrontal cortex. Rats were intraperitoneally administrated with ketamine at the dose of 10 mg/kg or saline 1 h before the second episode of the forced swimming test (FST. Tramadol or saline was intraperitoneally pretreated 30 min before the former administration of ketamine or saline. The locomotor activity and the immobility time of FST were both measured. After that, rats were sacrificed to determine the expression of mTOR in hippocampus and prefrontal cortex. Tramadol at the dose of 5 mg/kg administrated alone did not elicit the antidepressant effects. More importantly, pretreatment with tramadol enhanced the ketamine-induced antidepressant effects and upregulated the expression of mTOR in rat hippocampus and prefrontal cortex. Pretreatment with tramadol enhances the ketamine-induced antidepressant effects, which is associated with the increased expression of mTOR in rat hippocampus and prefrontal cortex.

  19. Mammalian Target of Rapamycin Signaling Pathway Changes with Intestinal Epithelial Cells Renewal Along Crypt-Villus Axis

    Directory of Open Access Journals (Sweden)

    Huansheng Yang

    2016-07-01

    Full Text Available Background/Aims: Understanding the mechanism that involves in regulating epithelial cells renewal is the fundamental of regulating intestinal mucosa development and functions and related diseases. The mechanistic target of rapamycin (mTOR signaling pathway involves in controlling various major processes by integrating intracellular and extracellular cues. The present experiment was conducted to test the correlation between the mTOR signaling pathway and intestinal epithelial cells renewal along crypt-villus axis (CVA. Methods: Intestinal epithelial cells were sequentially isolated from the jejunum of piglets along CVA, and the amount or phosphorylation level of proteins involved in cell cycle, mTOR signaling pathway, gene expression, and the antioxidant capacity in the isolated cells were measured. Results: The results showed that the amount of proteins involved in cell cycle decreased from crypt to villus tip. The amount or phosphorylation level of proteins related to mTOR signaling pathway in intestinal epithelial cells mainly decreased during maturation along CVA. The amount of proteins involved in gene expression and the antioxidant capacity also decreased from crypt to the top of villi. Conclusions: These results indicate that the mTOR signaling pathway may be involved in regulating the intestinal epithelial cells renewal along CVA and it may partly through affecting the antioxidant capacity and gene expression of intestinal epithelial cells. Further histological verification is needed to confirm the results of the present experiments.

  20. Fluoride-Induced Autophagy via the Regulation of Phosphorylation of Mammalian Targets of Rapamycin in Mice Leydig Cells.

    Science.gov (United States)

    Zhang, Jianhai; Zhu, Yuchen; Shi, Yan; Han, Yongli; Liang, Chen; Feng, Zhiyuan; Zheng, Heping; Eng, Michelle; Wang, Jundong

    2017-10-11

    Fluoride is known to impair testicular function and decrease testosterone levels, yet the underlying mechanisms remain inconclusive. The objective of this study is to investigate the roles of autophagy in fluoride-induced male reproductive toxicity using both in vivo and in vitro Leydig cell models. Using transmission electron microscopy and monodansylcadaverine staining, we observed increasing numbers of autophagosomes in testicular tissue, especially in Leydig cells of fluoride-exposed mice. Further study revealed that fluoride increased the levels of mRNA and protein expression of autophagy markers LC3, Beclin1, and Atg 5 in primary Leydig cells. Furthermore, fluoride inhibited the phosphorylation of mammalian targets of rapamycin and 4EBP1, which in turn resulted in a decrease in the levels of AKT and PI3K mRNA expression, as well as an elevation of the level of AMPK expression in both testes and primary Leydig cells. Additionally, fluoride exposure significantly changed the mRNA expression of the PDK1, TSC, and Atg13 regulator genes in primary Leydig cells but not in testicular cells. Taken together, our findings highlight the roles of autophagy in fluoride-induced testicular and Leydig cell damage and contribute to the elucidation of the underlying mechanisms of fluoride-induced male reproductive toxicity.

  1. Regulation of the Target of Rapamycin and Other Phosphatidylinositol 3-Kinase-Related Kinases by Membrane Targeting

    Directory of Open Access Journals (Sweden)

    Maristella De Cicco

    2015-09-01

    Full Text Available Phosphatidylinositol 3-kinase-related kinases (PIKKs play vital roles in the regulation of cell growth, proliferation, survival, and consequently metabolism, as well as in the cellular response to stresses such as ionizing radiation or redox changes. In humans six family members are known to date, namely mammalian/mechanistic target of rapamycin (mTOR, ataxia-telangiectasia mutated (ATM, ataxia- and Rad3-related (ATR, DNA-dependent protein kinase catalytic subunit (DNA-PKcs, suppressor of morphogenesis in genitalia-1 (SMG-1, and transformation/transcription domain-associated protein (TRRAP. All fulfill rather diverse functions and most of them have been detected in different cellular compartments including various cellular membranes. It has been suggested that the regulation of the localization of signaling proteins allows for generating a locally specific output. Moreover, spatial partitioning is expected to improve the reliability of biochemical signaling. Since these assumptions may also be true for the regulation of PIKK function, the current knowledge about the regulation of the localization of PIKKs at different cellular (membrane compartments by a network of interactions is reviewed. Membrane targeting can involve direct lipid-/membrane interactions as well as interactions with membrane-anchored regulatory proteins, such as, for example, small GTPases, or a combination of both.

  2. Phosphorylation of Ribosomal Protein S6 Mediates Mammalian Target of Rapamycin Complex 1-Induced Parathyroid Cell Proliferation in Secondary Hyperparathyroidism.

    Science.gov (United States)

    Volovelsky, Oded; Cohen, Gili; Kenig, Ariel; Wasserman, Gilad; Dreazen, Avigail; Meyuhas, Oded; Silver, Justin; Naveh-Many, Tally

    2016-04-01

    Secondary hyperparathyroidism is characterized by increased serum parathyroid hormone (PTH) level and parathyroid cell proliferation. However, the molecular pathways mediating the increased parathyroid cell proliferation remain undefined. Here, we found that the mTOR pathway was activated in the parathyroid of rats with secondary hyperparathyroidism induced by either chronic hypocalcemia or uremia, which was measured by increased phosphorylation of ribosomal protein S6 (rpS6), a downstream target of the mTOR pathway. This activation correlated with increased parathyroid cell proliferation. Inhibition of mTOR complex 1 by rapamycin decreased or prevented parathyroid cell proliferation in secondary hyperparathyroidism rats and in vitro in uremic rat parathyroid glands in organ culture. Knockin rpS6(p-/-) mice, in which rpS6 cannot be phosphorylated because of substitution of all five phosphorylatable serines with alanines, had impaired PTH secretion after experimental uremia- or folic acid-induced AKI. Uremic rpS6(p-/-) mice had no increase in parathyroid cell proliferation compared with a marked increase in uremic wild-type mice. These results underscore the importance of mTOR activation and rpS6 phosphorylation for the pathogenesis of secondary hyperparathyroidism and indicate that mTORC1 is a significant regulator of parathyroid cell proliferation through rpS6. Copyright © 2016 by the American Society of Nephrology.

  3. Reduced mammalian target of rapamycin activity facilitates mitochondrial retrograde signaling and increases life span in normal human fibroblasts

    Science.gov (United States)

    Lerner, Chad; Bitto, Alessandro; Pulliam, Daniel; Nacarelli, Timothy; Konigsberg, Mina; Van Remmen, Holly; Torres, Claudio; Sell, Christian

    2017-01-01

    Summary Coordinated expression of mitochondrial and nuclear genes is required to maintain proper mitochondrial function. However, the precise mechanisms that ensure this coordination are not well defined. We find that signaling from mitochondria to the nucleus is influenced by mammalian target of rapamycin (mTOR) activity via changes in autophagy and p62/SQSTM1 turnover. Reducing mTOR activity increases autophagic flux, enhances mitochondrial membrane potential, reduces reactive oxygen species within the cell, and increases replicative life span. These effects appear to be mediated in part by an interaction between p62/SQSTM1 and Keap1. This interaction allows nuclear accumulation of the nuclear factor erythroid 2-like 2 (NFE2L2, also known as nuclear factor related factor 2 or NRF2), increased expression of the nuclear respiratory factor 1 (NRF1), and increased expression of nuclear-encoded mitochondrial genes, such as the mitochondrial transcription factor A, and mitochondrial-encoded genes involved in oxidative phosphorylation. These findings reveal a portion of the intracellular signaling network that couples mitochondrial turnover with mitochondrial renewal to maintain homeostasis within the cell and suggest mechanisms whereby a reduction in mTOR activity may enhance longevity. PMID:23795962

  4. Ectopic expression of Arabidopsis Target of Rapamycin (AtTOR) improves water-use efficiency and yield potential in rice

    Science.gov (United States)

    Bakshi, Achala; Moin, Mazahar; Kumar, M. Udaya; Reddy, Aramati Bindu Madhava; Ren, Maozhi; Datla, Raju; Siddiq, E. A.; Kirti, P. B.

    2017-02-01

    The target of Rapamycin (TOR) present in all eukaryotes is a multifunctional protein, regulating growth, development, protein translation, ribosome biogenesis, nutrient, and energy signaling. In the present study, ectopic expression of TOR gene of Arabidopsis thaliana in a widely cultivated indica rice resulted in enhanced plant growth under water-limiting conditions conferring agronomically important water-use efficiency (WUE) trait. The AtTOR high expression lines of rice exhibited profuse tillering, increased panicle length, increased plant height, high photosynthetic efficiency, chlorophyll content and low ∆13C. Δ13C, which is inversely related to high WUE, was as low as 17‰ in two AtTOR high expression lines. These lines were also insensitive to the ABA-mediated inhibition of seed germination. The significant upregulation of 15 stress-specific genes in high expression lines indicates their contribution to abiotic stress tolerance. The constitutive expression of AtTOR is also associated with significant transcriptional upregulation of putative TOR complex-1 components, OsRaptor and OsLST8. Glucose-mediated transcriptional activation of AtTOR gene enhanced lateral root formation. Taken together, our findings indicate that TOR, in addition to its multiple cellular functions, also plays an important role in response to abiotic stress and potentially enhances WUE and yield related attributes.

  5. Grape polyphenols inhibit Akt/mammalian target of rapamycin signaling and potentiate the effects of gefitinib in breast cancer.

    Science.gov (United States)

    Castillo-Pichardo, Linette; Dharmawardhane, Suranganie F

    2012-01-01

    We recently reported that a combination of dietary grape polyphenols resveratrol, quercetin, and catechin (RQC), at low concentrations, was effective at inhibiting metastatic cancer progression. Herein, we investigate the molecular mechanisms of RQC in breast cancer and explore the potential of RQC as a potentiation agent for the epidermal growth factor receptor (EGFR) therapeutic gefitinib. Our in vitro experiments showed RQC induced apoptosis in gefitinib-resistant breast cancer cells via regulation of a myriad of proapoptotic proteins. Because the Akt/mammalian target of rapamycin (mTOR) signaling pathway is often elevated during development of anti-EGFR therapy resistance, the effect of RQC on the mTOR upstream effector Akt and the negative regulator AMP kinase (AMPK) was investigated. RQC was found to reduce Akt activity, induce the activation of AMPK, and inhibit mTOR signaling in breast cancer cells. Combined RQC and gefitinib decreased gefitinib resistant breast cancer cell viability to a greater extent than RQC or gefitinib alone. Moreover, RQC inhibited Akt and mTOR and activated AMPK even in the presence of gefitinib. Our in vivo experiments showed combined RQC and gefitinib was more effective than the individual treatments at inhibiting mammary tumor growth and metastasis in nude mice. Therefore, RQC treatment inhibits breast cancer progression and may potentiate anti-EGFR therapy by inhibition of Akt/mTOR signaling.

  6. Importance of EEG in validating the chronic effects of drugs: suggestions from animal models of epilepsy treated with rapamycin.

    Science.gov (United States)

    Cambiaghi, Marco; Magri, Laura; Cursi, Marco

    2015-04-01

    The development of new drugs for the treatment of epilepsy is a major challenge for modern neurology and its first steps demand basic research. Preclinical studies on animal models of epilepsy are mainly based on the analysis of brain electrical activity to detect seizures, when they are not just limited to behavioral tests like the Racine scale. In the present review, we discuss the importance of using time-locked video and EEG recordings (Video-EEG) coupled with behavioral tests as tools to monitor and analyze the effects of anti-epileptic drugs in pre-clinical research. Particularly, we focus on the utility of a multimodal approach based on EEG/behavioral analysis to study the beneficial effects of chronic rapamycin treatment as a potential anti-epileptogenic therapy for a broad spectrum of epilepsy, including both genetic (as in tuberous sclerosis complex) and acquired diseases. Changes and synchronization of neuronal activity of different areas have been correlated with specific behavior in both physiological and pathological conditions. In the epileptic brain, during a seizure there is an abnormal activation of many cells all at once, altering different networks. A multimodal approach based on video, EEG analysis and behavioral tests would be the best option in preclinical studies of epilepsy. Copyright © 2015 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

  7. Mammalian target of rapamycin complex 2 (mTORC2 is a critical determinant of bladder cancer invasion.

    Directory of Open Access Journals (Sweden)

    Sounak Gupta

    Full Text Available Bladder cancer is the fourth most common cause of cancer in males in the United States. Invasive behavior is a major determinant of prognosis. In this study, we identified mammalian target of rapamycin complex 2 (mTORC2 as a central regulator of bladder cancer cell migration and invasion. mTORC2 activity was assessed by the extent of phosphorylation of Ser473 in AKT and determined to be approximately 5-fold higher in specimens of invasive human bladder cancer as opposed to non-invasive human bladder cancer. The immortalized malignant bladder cell lines, UMUC-3, J82 and T24 demonstrated higher baseline mTORC2 activity relative to the benign bladder papilloma-derived cell line RT4 and the normal urothelial cell line HU1. The malignant bladder cancer cells also demonstrated increased migration in transwell and denudation assays, increased invasion of matrigel, and increased capacity to invade human bladder specimens. Gene silencing of rictor, a critical component of mTORC2, substantially inhibited bladder cancer cell migration and invasion. This was accompanied by a significant decrease in Rac1 activation and paxillin phosphorylation. These studies identify mTORC2 as a major target for neutralizing bladder cancer invasion.

  8. Rapamycin Attenuated Cardiac Hypertrophy Induced by Isoproterenol and Maintained Energy Homeostasis via Inhibiting NF-κB Activation

    Directory of Open Access Journals (Sweden)

    Xi Chen

    2014-01-01

    Full Text Available Rapamycin, also known as sirolimus, is an immunosuppressant drug used to prevent rejection organ (especially kidney transplantation. However, little is known about the role of Rapa in cardiac hypertrophy induced by isoproterenol and its underlying mechanism. In this study, Rapa was administrated intraperitoneally for one week after the rat model of cardiac hypertrophy induced by isoproterenol established. Rapa was demonstrated to attenuate isoproterenol-induced cardiac hypertrophy, maintain the structure integrity and functional performance of mitochondria, and upregulate genes related to fatty acid metabolism in hypertrophied hearts. To further study the implication of NF-κB in the protective role of Rapa, cardiomyocytes were pretreated with TNF-α or transfected with siRNA against NF-κB/p65 subunit. It was revealed that the upregulation of extracellular circulating proinflammatory cytokines induced by isoproterenol was able to be reversed by Rapa, which was dependent on NF-κB pathway. Furthermore, the regression of cardiac hypertrophy and maintaining energy homeostasis by Rapa in cardiomyocytes may be attributed to the inactivation of NF-κB. Our results shed new light on mechanisms underlying the protective role of Rapa against cardiac hypertrophy induced by isoproterenol, suggesting that blocking proinflammatory response by Rapa might contribute to the maintenance of energy homeostasis during the progression of cardiac hypertrophy.

  9. Gingipain-dependent degradation of mammalian target of rapamycin pathway proteins by the periodontal pathogen Porphyromonas gingivalis during invasion.

    Science.gov (United States)

    Stafford, P; Higham, J; Pinnock, A; Murdoch, C; Douglas, C W I; Stafford, G P; Lambert, D W

    2013-10-01

    Porphyromonas gingivalis and Tannerella forsythia are gram-negative pathogens strongly associated with periodontitis. Their abilities to interact, invade and persist within host cells are considered crucial to their pathogenicity, but the mechanisms by which they subvert host defences are not well understood. In this study, we set out to investigate whether P. gingivalis and T. forsythia directly target key signalling molecules that may modulate the host cell phenotype to favour invasion and persistence. Our data identify, for the first time, that P. gingivalis, but not T. forsythia, reduces levels of intracellular mammalian target of rapamycin (mTOR) in oral epithelial cells following invasion over a 4-h time course, via the action of gingipains. The ability of cytochalasin D to abrogate P. gingivalis-mediated mTOR degradation suggests that this effect is dependent upon cellular invasion. We also show that levels of several other proteins in the mTOR signalling pathway are modulated by gingipains, either directly or as a consequence of mTOR degradation including p-4E-BP1. Taken together, our data suggest that P. gingivalis manipulates the mTOR pathway, providing evidence for a potentially novel mechanism by which P. gingivalis mediates its effects on host cell responses to infection. 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd

  10. Imbalanced mechanistic target of rapamycin C1 and C2 activity in the cerebellum of Angelman syndrome mice impairs motor function.

    Science.gov (United States)

    Sun, Jiandong; Liu, Yan; Moreno, Stephanie; Baudry, Michel; Bi, Xiaoning

    2015-03-18

    Angelman syndrome (AS) is a neurogenetic disorder caused by deficiency of maternally expressed ubiquitin-protein ligase E3A (UBE3A), an E3 ligase that targets specific proteins for proteasomal degradation. Although motor function impairment occurs in all patients with AS, very little research has been done to understand and treat it. The present study focuses on Ube3A deficiency-induced alterations in signaling through the mechanistic target of rapamycin (mTOR) pathway in the cerebellum of the AS mouse model and on potential therapeutic applications of rapamycin. Levels of tuberous sclerosis complex 2 (TSC2), a negative regulator of mTOR, were increased in AS mice compared with wild-type mice; however, TSC2 inhibitory phosphorylation was also increased. Correspondingly, levels of phosphorylated/active mTOR were increased. Phosphorylation of the mTORC1 substrates S6 kinase 1 (S6K1) and S6 was elevated, whereas that of the mTORC2 substrates AKT and N-myc downstream regulated 1 was decreased, suggesting enhanced mTORC1 but inhibited mTORC2 signaling. Semi-chronic treatment of AS mice with rapamycin not only improved their motor performance but also normalized mTORC1 and mTORC2 signaling. Furthermore, inhibitory phosphorylation of rictor, a key regulatory/structural subunit of the mTORC2 complex, was increased in AS mice and decreased after rapamycin treatment. These results indicate that Ube3A deficiency leads to overactivation of the mTORC1-S6K1 pathway, which in turn inhibits rictor, resulting in decreased mTORC2 signaling in Purkinje neurons of AS mice. Finally, rapamycin treatment also improved dendritic spine morphology in AS mice, through inhibiting mTORC1 and possibly enhancing mTORC2-mediated regulation of synaptic cytoskeletal elements. Collectively, our results indicate that the imbalance between mTORC1 and mTORC2 activity may contribute to synaptic pathology and motor impairment in AS. Copyright © 2015 the authors 0270-6474/15/354706-13$15.00/0.

  11. The Inhibitory Effect of Rapamycin on Toll Like Receptor 4 and Interleukin 17 in the Early Stage of Rat Diabetic Nephropathy.

    Science.gov (United States)

    Yu, Ruichao; Bo, Hong; Villani, Vincenzo; Spencer, Philip J; Fu, Ping

    2016-01-01

    There is increasing evidence showing that innate immune responses and inflammatory processes play an important role in the development and progression of diabetic nephropathy (DN). The potential effect of innate immunity in the early stage of DN is still unclear. Toll-Like-Receptor 4 (TLR4) is vigorously involved in the progress of kidney diseases in a sterile environment. The activation of the interleukin 17 (IL-17) pathway produces inflammatory cytokines, appearing in various kidney diseases. Unfortunately the relationship between TLR4 and IL-17 has not been investigated in diabetic nephropathy to date. The aim of this study is to investigate whether mammalian target of rapamycin (mTOR) inhibition may be dependent on TLR4 signaling and the pro-inflammatory factor IL-17 to delay the progression of DN. Streptozotocin (STZ)-induced diabetic rats were randomly assigned to 3 experimental groups: a diabetic nephropathy group (DN, n = 6); and a diabetic nephropathy treated with rapamycin group (Rapa, n = 6) and a control group (Control, n =6). Body weight, fasting blood sugar, and 24h urine albumin were assessed at week 2, week 4 and week 8. Renal tissues were harvested for H&E, PAS staining, as well as an immunohistochemistry assay for TLR4 and IL-17. TLR4 quantitative expression was measured by Western-Blot analysis and RT-PCR. Our results demonstrated that the expression of both TLR4 and IL-17 were upregulated in early stage DN and reduced by rapamycin. TLR4 and IL-17 both increased and positively related to 24h urinary albumin and kidney/weight ratio. However, neither TLR4 nor IL-17 made a significant difference on fasting blood sugar. Taken together, our results confirm and extend previous studies identifying the significance of the TLR4 and Th17 pathways in development of early stage DN. Furthermore, we suggest this overexpression of TLR4 might be involved in the immunopathogenesis of DN through activation of Th17 cells. Rapamycin may attenuate DN via reduction of

  12. The Inhibitory Effect of Rapamycin on Toll Like Receptor 4 and Interleukin 17 in the Early Stage of Rat Diabetic Nephropathy

    Directory of Open Access Journals (Sweden)

    Ruichao Yu

    2016-02-01

    Full Text Available Background/Aims: There is increasing evidence showing that innate immune responses and inflammatory processes play an important role in the development and progression of diabetic nephropathy (DN. The potential effect of innate immunity in the early stage of DN is still unclear. Toll-Like-Receptor 4 (TLR4 is vigorously involved in the progress of kidney diseases in a sterile environment. The activation of the interleukin 17 (IL-17 pathway produces inflammatory cytokines, appearing in various kidney diseases. Unfortunately the relationship between TLR4 and IL-17 has not been investigated in diabetic nephropathy to date. The aim of this study is to investigate whether mammalian target of rapamycin (mTOR inhibition may be dependent on TLR4 signaling and the pro-inflammatory factor IL-17 to delay the progression of DN. Methods: Streptozotocin (STZ-induced diabetic rats were randomly assigned to 3 experimental groups: a diabetic nephropathy group (DN, n = 6; and a diabetic nephropathy treated with rapamycin group (Rapa, n = 6 and a control group (Control, n =6. Body weight, fasting blood sugar, and 24h urine albumin were assessed at week 2, week 4 and week 8. Renal tissues were harvested for H&E, PAS staining, as well as an immunohistochemistry assay for TLR4 and IL-17. TLR4 quantitative expression was measured by Western-Blot analysis and RT-PCR. Results: Our results demonstrated that the expression of both TLR4 and IL-17 were upregulated in early stage DN and reduced by rapamycin. TLR4 and IL-17 both increased and positively related to 24h urinary albumin and kidney/weight ratio. However, neither TLR4 nor IL-17 made a significant difference on fasting blood sugar. Conclusions: Taken together, our results confirm and extend previous studies identifying the significance of the TLR4 and Th17 pathways in development of early stage DN. Furthermore, we suggest this overexpression of TLR4 might be involved in the immunopathogenesis of DN through

  13. MicroRNA-99a inhibits insulin-induced proliferation, migration, dedifferentiation, and rapamycin resistance of vascular smooth muscle cells by inhibiting insulin-like growth factor-1 receptor and mammalian target of rapamycin.

    Science.gov (United States)

    Zhang, Zi-Wei; Guo, Rui-Wei; Lv, Jin-Lin; Wang, Xian-Mei; Ye, Jin-Shan; Lu, Ni-Hong; Liang, Xing; Yang, Li-Xia

    2017-04-29

    Patients with type 2 diabetes mellitus (T2DM) are characterized by insulin resistance and are subsequently at high risk for atherosclerosis. Hyperinsulinemia has been associated with proliferation, migration, and dedifferentiation of vascular smooth muscle cells (VSMCs) during the pathogenesis of atherosclerosis. Moreover, insulin-like growth factor-1 receptor (IGF-1R) and mammalian target of rapamycin (mTOR) have been demonstrated to be the underlying signaling pathways. Recently, microRNA-99a (miR-99a) has been suggested to regulate the phenotypic changes of VSMCs in cancer cells. However, whether it is involved in insulin-induced changes of VSCMs has not been determined. In this study, we found that insulin induced proliferation, migration, and dedifferentiation of mouse VSMCs in a dose-dependent manner. Furthermore, the stimulating effects of high-dose insulin on proliferation, migration, and dedifferentiation of mouse VSMCs were found to be associated with the attenuation of the inhibitory effects of miR-99a on IGF-1R and mTOR signaling activities. Finally, we found that the inducing effect of high-dose insulin on proliferation, migration, and dedifferentiation of VSMCs was partially inhibited by an active mimic of miR-99a. Taken together, these results suggest that miR-99a plays a key regulatory role in the pathogenesis of insulin-induced proliferation, migration, and phenotype conversion of VSMCs at least partly via inhibition of IGF-1R and mTOR signaling. Our results provide evidence that miR-99a may be a novel target for the treatment of hyperinsulinemia-induced atherosclerosis. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Slow-releasing rapamycin-coated bionic peripheral nerve scaffold promotes the regeneration of rat sciatic nerve after injury.

    Science.gov (United States)

    Ding, Tan; Zhu, Chao; Yin, Jun-Bin; Zhang, Ting; Lu, Ya-Cheng; Ren, Jun; Li, Yun-Qing

    2015-02-01

    To investigate the effect of locally slow-released rapamycin (RAPA) from the bionic peripheral nerve scaffold on rat sciatic nerve regeneration in the early phase of nerve injury. Slow-releasing RAPA-polyhydroxy alcohol (PLGA) microspheres were prepared and tested for microsphere diameter and slow-release effect in vitro after loading onto nerve scaffold. A total of 48 male SD rats were randomly divided into control group and 3 experimental groups as follows: group 1: RAPA-PLGA scaffold; group 2: RAPA scaffold; and group 3: scaffold alone. In the control group, a 15mm sciatic nerve was excised and religated reversely. In the experimental groups, the scaffolds were used to bridge a defect of 15mm sciatic nerve. The outcome of nerve regeneration was evaluated using neurophysiological and neuromuscular morphological techniques. The RAPA-PLGA microspheres displayed a smooth exterior. The slow-release of RAPA in group 1 lasted for 14days. The sciatic nerve function index (SFI) and electrophysiological and morphological features were examined 12weeks after the surgery in all groups to reveal various degrees of ipsilateral sciatic nerve regeneration. The SFI values at 12weeks showed no significant difference between the RAPA-PLGA scaffold and control groups; morphological observations revealed that the outcomes of nerve regeneration in the above 2 groups were similar and significantly better than those in the RAPA scaffold and scaffold alone groups. RAPA-PLGA microsphere-loaded bionic peripheral nerve scaffold gradually released RAPA locally in the early phase of sciatic nerve regeneration, reduced the secondary nerve injury, and evidently promoted the regeneration of peripheral nerve. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Immunohistochemical Analysis of the Mechanistic Target of Rapamycin and Hypoxia Signalling Pathways in Basal Cell Carcinoma and Trichoepithelioma

    Science.gov (United States)

    Brinkhuizen, Tjinta; Weijzen, Chantal A. H.; Eben, Jonathan; Thissen, Monique R.; van Marion, Ariënne M.; Lohman, Björn G.; Winnepenninckx, Véronique J. L.; Nelemans, Patty J.; van Steensel, Maurice A. M.

    2014-01-01

    Background Basal cell carcinoma (BCC) is the most common cancer in Caucasians. Trichoepithelioma (TE) is a benign neoplasm that strongly resembles BCC. Both are hair follicle (HF) tumours. HFs are hypoxic microenvironments, therefore we hypothesized that hypoxia-induced signalling pathways could be involved in BCC and TE as they are in other human malignancies. Hypoxia-inducible factor 1 (HIF1) and mechanistic/mammalian target of rapamycin (mTOR) are key players in these pathways. Objectives To determine whether HIF1/mTOR signalling is involved in BCC and TE. Methods We used immunohistochemical staining of formalin-fixed paraffin-embedded BCC (n = 45) and TE (n = 35) samples to assess activity of HIF1, mTORC1 and their most important target genes. The percentage positive tumour cells was assessed manually in a semi-quantitative manner and categorized (0%, 80%). Results Among 45 BCC and 35 TE examined, expression levels were respectively 81% and 57% (BNIP3), 73% and 75% (CAIX), 79% and 86% (GLUT1), 50% and 19% (HIF1α), 89% and 88% (pAKT), 55% and 61% (pS6), 15% and 25% (pMTOR), 44% and 63% (PHD2) and 44% and 49% (VEGF-A). CAIX, Glut1 and PHD2 expression levels were significantly higher in TE when only samples with at least 80% expression were included. Conclusions HIF and mTORC1 signalling seems active in both BCC and TE. There are no appreciable differences between the two with respect to pathway activity. At this moment immunohistochemical analyses of HIF, mTORC1 and their target genes does not provide a reliable diagnostic tool for the discrimination of BCC and TE. PMID:25181405

  16. Immunohistochemical analysis of the mechanistic target of rapamycin and hypoxia signalling pathways in basal cell carcinoma and trichoepithelioma.

    Directory of Open Access Journals (Sweden)

    Tjinta Brinkhuizen

    Full Text Available BACKGROUND: Basal cell carcinoma (BCC is the most common cancer in Caucasians. Trichoepithelioma (TE is a benign neoplasm that strongly resembles BCC. Both are hair follicle (HF tumours. HFs are hypoxic microenvironments, therefore we hypothesized that hypoxia-induced signalling pathways could be involved in BCC and TE as they are in other human malignancies. Hypoxia-inducible factor 1 (HIF1 and mechanistic/mammalian target of rapamycin (mTOR are key players in these pathways. OBJECTIVES: To determine whether HIF1/mTOR signalling is involved in BCC and TE. METHODS: We used immunohistochemical staining of formalin-fixed paraffin-embedded BCC (n = 45 and TE (n = 35 samples to assess activity of HIF1, mTORC1 and their most important target genes. The percentage positive tumour cells was assessed manually in a semi-quantitative manner and categorized (0%, 80%. RESULTS: Among 45 BCC and 35 TE examined, expression levels were respectively 81% and 57% (BNIP3, 73% and 75% (CAIX, 79% and 86% (GLUT1, 50% and 19% (HIF1α, 89% and 88% (pAKT, 55% and 61% (pS6, 15% and 25% (pMTOR, 44% and 63% (PHD2 and 44% and 49% (VEGF-A. CAIX, Glut1 and PHD2 expression levels were significantly higher in TE when only samples with at least 80% expression were included. CONCLUSIONS: HIF and mTORC1 signalling seems active in both BCC and TE. There are no appreciable differences between the two with respect to pathway activity. At this moment immunohistochemical analyses of HIF, mTORC1 and their target genes does not provide a reliable diagnostic tool for the discrimination of BCC and TE.

  17. Renal function in heart transplant patients after switch to combined mammalian target of rapamycin inhibitor and calcineurin inhibitor therapy

    Directory of Open Access Journals (Sweden)

    Helmschrott M

    2017-06-01

    Full Text Available Matthias Helmschrott,1 Rasmus Rivinius,1 Thomas Bruckner,2 Hugo A Katus,1 Andreas O Doesch1 1Department of Cardiology, Angiology, Pneumology, 2Institute for Medical Biometry and Informatics, University of Heidelberg, Heidelberg, Germany Background: A calcineurin inhibitor (CNI-based immunosuppression combined with mammalian target of rapamycin inhibitors (mTORs seems to be attractive in patients after heart transplantation (HTX in special clinical situations, for example, in patients with adverse drug effects of prior immunosuppression. Previous studies in patients after HTX detected advantageous effects regarding renal function of a tacrolimus (TAC-based vs cyclosporine-A (CSA-based immunosuppression (in combination with mycophenolate mofetil. However, data regarding renal function after HTX in mTOR/CNI patients remain limited. Aim: Primary end point of the present study was to analyze renal function in HTX patients 1 year after switch to an mTOR/CNI-based immunosuppression. Methods: Data of 80 HTX patients after change to mTOR/CNI-based immunosuppression were retrospectively analyzed. Renal function was assessed by measured serum creatinine and by estimated glomerular filtration rate (eGFR calculated from Modification of Diet in Renal Disease equation. Results: Twenty-nine patients received mTOR/CSA-based treatment and 51 patients received mTOR/TAC-based therapy. At time of switch and at 1-year follow-up, serum creatinine and eGFR did not differ significantly between both study groups (all P=not statistically significant. Analysis of variances with repeated measurements detected a similar change of renal function in both study groups. Conclusion: The present study detected no significant differences between both mTOR/CNI study groups, indicating a steady state of renal function in HTX patients after switch of immunosuppressive regimen. Keywords: heart transplantation, cyclosporine A, tacrolimus, risk factors

  18. Aortic eNOS expression and phosphorylation in Apo-E knockout mice: differing effects of rapamycin and simvastatin.

    Science.gov (United States)

    Naoum, Joseph J; Zhang, Shu; Woodside, Kenneth J; Song, Wei; Guo, Qian; Belalcazar, Ligia M; Hunter, Glenn C

    2004-08-01

    The inhibition of nitric oxide (NO) by hypercholesterolemia may be mediated, in part, by interactions with caveolin-1 (Cav-1). Because of the facilitatory effects of statins on endothelial function and the adverse effects of rapamycin (RAPA) on plasma lipids, we compared the effects of simvastatin (SMV) and RAPA on endothelial NO synthase (eNOS) and Cav-1 protein expression and phosphorylation in the aortas of apolipoprotein E (Apo-E) knockout (-/-) mice. Apo-E -/- mice (n = 38) fed a high-cholesterol diet were given SMV (100 mg/kg/day po), RAPA (3 mg/kg/day ip), or no treatment for 10 weeks. Blood was drawn for serum lipid analysis, and protein was extracted for Western immunoblotting. Selected aortic specimens from 2 animals in each group were examined by histology and immunohistochemistry. The data are expressed as the mean +/- SEM and compared by the Student t test and ANOVA. Significance was established as P < .05. Lipid levels at 10 weeks were similar in the 3 groups except for higher triglyceride levels in RAPA-treated animals. eNOS expression was highest in RAPA-treated mice, but the p-eNOS to eNOS protein expression ratio was significantly greater in the SMV treatment group compared to both RAPA and controls (P < .05). Both Cav-1 and p-Cav-1 expression was significantly lower in the SMV-treated animals (P < .05) compared to mice treated with RAPA. Although eNOS expression was greatest in the RAPA-treated mice, the expression of p-eNOS was similar in the RAPA- and SMV-treated animals. The increase in eNOS induced by RAPA and the inverse relationship between p-eNOS and Cav-1 protein expression observed with SMV treatment suggest different mechanisms for the regulation of aortic eNOS expression in Apo-E mice by these 2 agents. Copyright 2004 Elsevier Inc.

  19. Migratory properties of ex vivo expanded regulatory T cells: Influence of all-trans retinoic acid and rapamycin.

    Science.gov (United States)

    Beermann, J L; Thiesler, C T; Dringenberg, U; Alter, C; Kuhs, S; Velaga, S; Ukena, S N; Franzke, A

    2017-12-01

    Adoptively transferred regulatory T-cells represent a promising therapeutic approach for tolerance induction in autoimmunity and transplantation medicine. However, a major hurdle for clinical application is the manufacturing of sufficient Treg cell numbers with respect to the low frequency of naturally occurring Tregs in the peripheral blood. Therefore, ex vivo large-scale expansion is mandatory for most of the clinical conditions. Besides the Treg cell number other parameters of the cell product are of high relevance for safe and efficient clinical Treg cell application like Treg cell purity, suppressive capacity and genetic stability of the Treg cell phenotype. Moreover, migratory properties of ex vivo expanded Tregs should be defined very clearly in order to predict their migration to secondary lymphoid organs as sites of antigen-specific activation, in vivo proliferation and subsequent trafficking to affected target organs. Therefore, we studied different cell culture conditions for Treg large-cell expansion using all-trans retinoic acid (ATRA) and/or rapamycin (Rapa) with focus on their migratory properties. The tested culture conditions revealed comparable chemokine receptor expression profiles (CXCR3, CCR4, CCR6, CCR7) and functional migration capabilities (IP10 and CCL19) with respect to Th1 and Th2 inflammatory conditions. However, the most striking difference was detected for the expansion capacity, suppressive potency and genetic stability likely predisposing large-scale expansion with ATRA and/or Rapa for therapeutic intervention in acute GvHD and without supplementation for chronic GvHD. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Anti-aging pharmacology in cutaneous wound healing: effects of metformin, resveratrol, and rapamycin by local application.

    Science.gov (United States)

    Zhao, Pan; Sui, Bing-Dong; Liu, Nu; Lv, Ya-Jie; Zheng, Chen-Xi; Lu, Yong-Bo; Huang, Wen-Tao; Zhou, Cui-Hong; Chen, Ji; Pang, Dan-Lin; Fei, Dong-Dong; Xuan, Kun; Hu, Cheng-Hu; Jin, Yan

    2017-10-01

    Cutaneous wounds are among the most common soft tissue injuries and are particularly hard to heal in aging. Caloric restriction (CR) is well documented to extend longevity; pharmacologically, profound rejuvenative effects of CR mimetics have been uncovered, especially metformin (MET), resveratrol (RSV), and rapamycin (RAPA). However, locally applied impacts and functional differences of these agents on wound healing remain to be established. Here, we discovered that chronic topical administration of MET and RSV, but not RAPA, accelerated wound healing with improved epidermis, hair follicles, and collagen deposition in young rodents, and MET exerted more profound effects. Furthermore, locally applied MET and RSV improved vascularization of the wound beds, which were attributed to stimulation of adenosine monophosphate-activated protein kinase (AMPK) pathway, the key mediator of wound healing. Notably, in aged skin, AMPK pathway was inhibited, correlated with impaired vasculature and reduced healing ability. As therapeutic approaches, local treatments of MET and RSV prevented age-related AMPK suppression and angiogenic inhibition in wound beds. Moreover, in aged rats, rejuvenative effects of topically applied MET and RSV on cell viability of wound beds were confirmed, of which MET showed more prominent anti-aging effects. We further verified that only MET promoted wound healing and cutaneous integrity in aged skin. These findings clarified differential effects of CR-based anti-aging pharmacology in wound healing, identified critical angiogenic and rejuvenative mechanisms through AMPK pathway in both young and aged skin, and unraveled chronic local application of MET as the optimal and promising regenerative agent in treating cutaneous wound defects. © 2017 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

  1. CD4(+CD25(-Nrp1(+ T cells synergize with rapamycin to prevent murine cardiac allorejection in immunocompetent recipients.

    Directory of Open Access Journals (Sweden)

    Qing Yuan

    Full Text Available Besides CD4(+CD25(+Foxp3(+ regulatory T cells (Tregs, other immunosuppressive T cells also participated in the regulation of immune tolerance. Reportedly, neuropilin-1 (Nrp1 might be one of the molecules by which regulatory cells exert their suppressive effects. Indeed, CD4(+CD25(-Nrp1(+ T cells exhibit potent suppressive function in autoimmune inflammatory responses. Here we investigated the specific role of CD4(+CD25(-Nrp1(+ T cells in the setting of the transplant immune response. Through MLR assays, we found that CD4(+CD25(-Nrp1(+ T cells suppressed the proliferation of naive CD4(+CD25(- T cells activated by allogeneic antigen-stimulation. Adoptive transfer of CD4(+CD25(-Nrp1(+ T cells synergized with rapamycin to induce long-term graft survival in fully MHC-mismatched murine heart transplantation, which was associated with decreased IFN-γ, IL-17 and increased IL-10, TGF-β, Foxp3 and Nrp1 expression in the grafts. Importantly, our data indicated that CD4(+CD25(-Nrp1(+ T cell transfer augments the accumulation of Tregs in the recipient, and creates conditions that favored induction of hyporesponsiveness of the T effector cells. In conclusion, this translational study indicates the possible therapeutic potential of CD4(+CD25(-Nrp1(+ T cells in preventing allorejection. CD4(+Nrp1(+ T cells might therefore be used in bulk as a population of immunosuppressive cells with more beneficial properties concerning ex vivo isolation as compared to Foxp3(+ Tregs.

  2. Cryptotanshinone inhibition of mammalian target of rapamycin pathway is dependent on oestrogen receptor alpha in breast cancer.

    Science.gov (United States)

    Pan, Yanhong; Shi, Junfeng; Ni, Wenting; Liu, Yuping; Wang, Siliang; Wang, Xu; Wei, Zhonghong; Wang, Aiyun; Chen, Wenxing; Lu, Yin

    2017-09-01

    Cryptotanshinone (CPT) has been demonstrated to inhibit proliferation and mammalian target of rapamycin (mTOR) pathway in MCF-7 breast cancer cells. However, the same results are unable to be repeated in MDA-MB-231 cells. Given the main difference of oestrogen receptor α (ERα) between two types of breast cancer cells, It is possibly suggested that CPT inhibits mTOR pathway dependent on ERα in breast cancer. CPT could significantly inhibit cell proliferation of ERα-positive cancer cells, whereas ERα-negative cancer cells are insensitive to CPT. The molecular docking results indicated that CPT has a high affinity with ERα, and the oestrogen receptor element luciferase reporter verified CPT distinct anti-oestrogen effect. Furthermore, CPT inhibits mTOR signalling in MCF-7 cells, but not in MDA-MB-231 cells, which is independent on binding to the FKBP12 and disrupting the mTOR complex. Meanwhile, increased expression of phosphorylation AKT and insulin receptor substrate (IRS1) induced by insulin-like growth factor 1 (IGF-1) was antagonized by CPT, but other molecules of IGF-1/AKT/mTOR signalling pathway such as phosphatase and tensin homolog (PTEN) and phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) were negatively affected. Finally, the MCF-7 cells transfected with shERα for silencing ERα show resistant to CPT, and p-AKT, phosphorylation of p70 S6 kinase 1 (p-S6K1) and eukaryotic initiation factor 4E binding protein 1 (4E-BP1) were partially recovered, suggesting ERα is required for CPT inhibition of mTOR signalling. Overall, CPT inhibition of mTOR is dependent on ERα in breast cancer and should be a potential anti-oestrogen agent and a natural adjuvant for application in endocrine resistance therapy. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  3. Branched Chain Amino Acid Suppresses Hepatocellular Cancer Stem Cells through the Activation of Mammalian Target of Rapamycin

    Science.gov (United States)

    Nishitani, Shinobu; Horie, Mayumi; Ishizaki, Sonoko; Yano, Hirohisa

    2013-01-01

    Differentiation of cancer stem cells (CSCs) into cancer cells causes increased sensitivity to chemotherapeutic agents. Although inhibition of mammalian target of rapamycin (mTOR) leads to CSC survival, the effect of branched chain amino acids (BCAAs), an mTOR complex 1 (mTORC1) activator remains unknown. In this study, we examined the effects of BCAA on hepatocellular carcinoma (HCC) cells expressing a hepatic CSC marker, EpCAM. We examined the effects of BCAA and/or 5-fluorouracil (FU) on expression of EpCAM and other CSC-related markers, as well as cell proliferation in HCC cells and in a xenograft mouse model. We also characterized CSC-related and mTOR signal-related molecule expression and tumorigenicity in HCC cells with knockdown of Rictor or Raptor, or overexpression of constitutively active rheb (caRheb). mTOR signal-related molecule expression was also examined in BCAA-treated HCC cells. In-vitro BCAA reduced the frequency of EpCAM-positive cells and improved sensitivity to the anti-proliferative effect of 5-FU. Combined 5-FU and BCAA provided better antitumor efficacy than 5-FU alone in the xenograft model. Stimulation with high doses of BCAA activated mTORC1. Knockdown and overexpression experiments revealed that inhibition of mTOR complex 2 (mTORC2) or activation of mTORC1 led to decreased EpCAM expression and little or no tumorigenicity. BCAA may enhance the sensitivity to chemotherapy by reducing the population of cscs via the mTOR pathway. This result suggests the utility of BCAA in liver cancer therapy. PMID:24312415

  4. Dynamin-dependent amino acid endocytosis activates mechanistic target of rapamycin complex 1 (mTORC1).

    Science.gov (United States)

    Shibutani, Shusaku; Okazaki, Hana; Iwata, Hiroyuki

    2017-11-03

    The mechanistic target of rapamycin complex 1 (mTORC1) is a master regulator of protein synthesis and potential target for modifying cellular metabolism in various conditions, including cancer and aging. mTORC1 activity is tightly regulated by the availability of extracellular amino acids, and previous studies have revealed that amino acids in the extracellular fluid are transported to the lysosomal lumen. There, amino acids induce recruitment of cytoplasmic mTORC1 to the lysosome by the Rag GTPases, followed by mTORC1 activation by the small GTPase Ras homolog enriched in brain (Rheb). However, how the extracellular amino acids reach the lysosomal lumen and activate mTORC1 remains unclear. Here, we show that amino acid uptake by dynamin-dependent endocytosis plays a critical role in mTORC1 activation. We found that mTORC1 is inactivated when endocytosis is inhibited by overexpression of a dominant-negative form of dynamin 2 or by pharmacological inhibition of dynamin or clathrin. Consistently, the recruitment of mTORC1 to the lysosome was suppressed by the dynamin inhibition. The activity and lysosomal recruitment of mTORC1 were rescued by increasing intracellular amino acids via cycloheximide exposure or by Rag overexpression, indicating that amino acid deprivation is the main cause of mTORC1 inactivation via the dynamin inhibition. We further show that endocytosis inhibition does not induce autophagy even though mTORC1 inactivation is known to strongly induce autophagy. These findings open new perspectives for the use of endocytosis inhibitors as potential agents that can effectively inhibit nutrient utilization and shut down the upstream signals that activate mTORC1. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  5. The role of phosphoinositide 3-kinase and phosphatidic acid in the regulation of mammalian target of rapamycin following eccentric contractions.

    Science.gov (United States)

    O'Neil, T K; Duffy, L R; Frey, J W; Hornberger, T A

    2009-07-15

    Resistance exercise induces a hypertrophic response in skeletal muscle and recent studies have begun to shed light on the molecular mechanisms involved in this process. For example, several studies indicate that signalling by the mammalian target of rapamycin (mTOR) is necessary for a hypertrophic response. Furthermore, resistance exercise has been proposed to activate mTOR signalling through an upstream pathway involving the phosphoinositide 3-kinase (PI3K) and protein kinase B (PKB); however, this hypothesis has not been thoroughly tested. To test this hypothesis, we first evaluated the temporal pattern of signalling through PI3K-PKB and mTOR following a bout of resistance exercise with eccentric contractions (EC). Our results indicated that the activation of signalling through PI3K-PKB is a transient event (12 h). Furthermore, inhibition of PI3K-PKB activity did not prevent the activation of mTOR signalling by ECs, indicating that PI3K-PKB is not part of the upstream regulatory pathway. These observations led us to investigate an alternative pathway for the activation of mTOR signalling involving the synthesis of phosphatidic acid (PA) by phospholipase D (PLD). Our results demonstrate that ECs induce a sustained elevation in [PA] and inhibiting the synthesis of PA by PLD prevented the activation of mTOR. Furthermore, we determined that similar to ECs, PA activates mTOR signalling through a PI3K-PKB-independent mechanism. Combined, the results of this study indicate that the activation of mTOR following eccentric contractions occurs through a PI3K-PKB-independent mechanism that requires PLD and PA.

  6. Critical analysis of the potential for therapeutic targeting of mammalian target of rapamycin (mTOR in gastric cancer

    Directory of Open Access Journals (Sweden)

    Inokuchi M

    2014-04-01

    Full Text Available Mikito Inokuchi,1 Keiji Kato,1 Kazuyuki Kojima,2 Kenichi Sugihara1 1Department of Surgical Oncology, 2Department of Minimally Invasive Surgery, Tokyo Medical and Dental University, Tokyo, Japan Abstract: Multidisciplinary treatment including chemotherapy has become the global standard of care for patients with metastatic gastric cancer (mGC; nonetheless, survival remains poor. Although many molecular-targeted therapies have been developed for various cancers, only anti-HER2 treatment has produced promising results in patients with mGC. Mammalian target of rapamycin (mTOR plays a key role in cell proliferation, antiapoptosis, and metastasis in signaling pathways from the tyrosine kinase receptor, and its activation has been demonstrated in gastric cancer (GC cells. This review discusses the clinical relevance of mTOR in GC and examines its potential as a therapeutic target in patients with mGC. Preclinical studies in animal models suggest that suppression of the mTOR pathway inhibits the proliferation of GC cells and delays tumor progression. The mTOR inhibitor everolimus has been evaluated as second- or third-line treatment in clinical trials. Adverse events were well tolerated although the effectiveness of everolimus alone was limited. Everolimus is now being evaluated in combination with chemotherapy in Phase III clinical studies in this subgroup of patients. Two Phase III studies include exploratory biomarker research designed to evaluate the predictive value of the expression or mutation of molecules related to the Akt/mTOR signaling pathway. These biomarker studies may lead to the realization of targeted therapy for selected patients with mGC in the future. Keywords: gastric cancer, mTOR, everolimus

  7. Yeast m6A Methylated mRNAs Are Enriched on Translating Ribosomes during Meiosis, and under Rapamycin Treatment.

    Science.gov (United States)

    Bodi, Zsuzsanna; Bottley, Andrew; Archer, Nathan; May, Sean T; Fray, Rupert G

    2015-01-01

    Interest in mRNA methylation has exploded in recent years. The sudden interest in a 40 year old discovery was due in part to the finding of FTO's (Fat Mass Obesity) N6-methyl-adenosine (m6A) deaminase activity, thus suggesting a link between obesity-associated diseases and the presence of m6A in mRNA. Another catalyst of the sudden rise in mRNA methylation research was the release of mRNA methylomes for human, mouse and Saccharomyces cerevisiae. However, the molecular function, or functions of this mRNA 'epimark' remain to be discovered. There is supportive evidence that m6A could be a mark for mRNA degradation due to its binding to YTH domain proteins, and consequently being chaperoned to P bodies. Nonetheless, only a subpopulation of the methylome was found binding to YTHDF2 in HeLa cells.The model organism Saccharomyces cerevisiae, has only one YTH domain protein (Pho92, Mrb1), which targets PHO4 transcripts for degradation under phosphate starvation. However, mRNA methylation is only found under meiosis inducing conditions, and PHO4 transcripts are apparently non-methylated. In this paper we set out to investigate if m6A could function alternatively to being a degradation mark in S. cerevisiae; we also sought to test whether it can be induced under non-standard sporulation conditions. We find a positive association between the presence of m6A and message translatability. We also find m6A induction following prolonged rapamycin treatment.

  8. Yeast m6A Methylated mRNAs Are Enriched on Translating Ribosomes during Meiosis, and under Rapamycin Treatment.

    Directory of Open Access Journals (Sweden)

    Zsuzsanna Bodi

    Full Text Available Interest in mRNA methylation has exploded in recent years. The sudden interest in a 40 year old discovery was due in part to the finding of FTO's (Fat Mass Obesity N6-methyl-adenosine (m6A deaminase activity, thus suggesting a link between obesity-associated diseases and the presence of m6A in mRNA. Another catalyst of the sudden rise in mRNA methylation research was the release of mRNA methylomes for human, mouse and Saccharomyces cerevisiae. However, the molecular function, or functions of this mRNA 'epimark' remain to be discovered. There is supportive evidence that m6A could be a mark for mRNA degradation due to its binding to YTH domain proteins, and consequently being chaperoned to P bodies. Nonetheless, only a subpopulation of the methylome was found binding to YTHDF2 in HeLa cells.The model organism Saccharomyces cerevisiae, has only one YTH domain protein (Pho92, Mrb1, which targets PHO4 transcripts for degradation under phosphate starvation. However, mRNA methylation is only found under meiosis inducing conditions, and PHO4 transcripts are apparently non-methylated. In this paper we set out to investigate if m6A could function alternatively to being a degradation mark in S. cerevisiae; we also sought to test whether it can be induced under non-standard sporulation conditions. We find a positive association between the presence of m6A and message translatability. We also find m6A induction following prolonged rapamycin treatment.

  9. Branched chain amino acid suppresses hepatocellular cancer stem cells through the activation of mammalian target of rapamycin.

    Directory of Open Access Journals (Sweden)

    Shinobu Nishitani

    Full Text Available Differentiation of cancer stem cells (CSCs into cancer cells causes increased sensitivity to chemotherapeutic agents. Although inhibition of mammalian target of rapamycin (mTOR leads to CSC survival, the effect of branched chain amino acids (BCAAs, an mTOR complex 1 (mTORC1 activator remains unknown. In this study, we examined the effects of BCAA on hepatocellular carcinoma (HCC cells expressing a hepatic CSC marker, EpCAM. We examined the effects of BCAA and/or 5-fluorouracil (FU on expression of EpCAM and other CSC-related markers, as well as cell proliferation in HCC cells and in a xenograft mouse model. We also characterized CSC-related and mTOR signal-related molecule expression and tumorigenicity in HCC cells with knockdown of Rictor or Raptor, or overexpression of constitutively active rheb (caRheb. mTOR signal-related molecule expression was also examined in BCAA-treated HCC cells. In-vitro BCAA reduced the frequency of EpCAM-positive cells and improved sensitivity to the anti-proliferative effect of 5-FU. Combined 5-FU and BCAA provided better antitumor efficacy than 5-FU alone in the xenograft model. Stimulation with high doses of BCAA activated mTORC1. Knockdown and overexpression experiments revealed that inhibition of mTOR complex 2 (mTORC2 or activation of mTORC1 led to decreased EpCAM expression and little or no tumorigenicity. BCAA may enhance the sensitivity to chemotherapy by reducing the population of cscs via the mTOR pathway. This result suggests the utility of BCAA in liver cancer therapy.

  10. Analysis of Proteins That Rapidly Change Upon Mechanistic/Mammalian Target of Rapamycin Complex 1 (mTORC1) Repression Identifies Parkinson Protein 7 (PARK7) as a Novel Protein Aberrantly Expressed in Tuberous Sclerosis Complex (TSC).

    Science.gov (United States)

    Niere, Farr; Namjoshi, Sanjeev; Song, Ehwang; Dilly, Geoffrey A; Schoenhard, Grant; Zemelman, Boris V; Mechref, Yehia; Raab-Graham, Kimberly F

    2016-02-01

    Many biological processes involve the mechanistic/mammalian target of rapamycin complex 1 (mTORC1). Thus, the challenge of deciphering mTORC1-mediated functions during normal and pathological states in the central nervous system is challenging. Because mTORC1 is at the core of translation, we have investigated mTORC1 function in global and regional protein expression. Activation of mTORC1 has been generally regarded to promote translation. Few but recent works have shown that suppression of mTORC1 can also promote local protein synthesis. Moreover, excessive mTORC1 activation during diseased states represses basal and activity-induced protein synthesis. To determine the role of mTORC1 activation in protein expression, we have used an unbiased, large-scale proteomic approach. We provide evidence that a brief repression of mTORC1 activity in vivo by rapamycin has little effect globally, yet leads to a significant remodeling of synaptic proteins, in particular those proteins that reside in the postsynaptic density. We have also found that curtailing the activity of mTORC1 bidirectionally alters the expression of proteins associated with epilepsy, Alzheimer's disease, and autism spectrum disorder-neurological disorders that exhibit elevated mTORC1 activity. Through a protein-protein interaction network analysis, we have identified common proteins shared among these mTORC1-related diseases. One such protein is Parkinson protein 7, which has been implicated in Parkinson's disease, yet not associated with epilepsy, Alzheimers disease, or autism spectrum disorder. To verify our finding, we provide evidence that the protein expression of Parkinson protein 7, including new protein synthesis, is sensitive to mTORC1 inhibition. Using a mouse model of tuberous sclerosis complex, a disease that displays both epilepsy and autism spectrum disorder phenotypes and has overactive mTORC1 signaling, we show that Parkinson protein 7 protein is elevated in the dendrites and colocalizes

  11. Analysis of Proteins That Rapidly Change Upon Mechanistic/Mammalian Target of Rapamycin Complex 1 (mTORC1) Repression Identifies Parkinson Protein 7 (PARK7) as a Novel Protein Aberrantly Expressed in Tuberous Sclerosis Complex (TSC)*

    Science.gov (United States)

    Niere, Farr; Namjoshi, Sanjeev; Song, Ehwang; Dilly, Geoffrey A.; Schoenhard, Grant; Zemelman, Boris V.; Mechref, Yehia; Raab-Graham, Kimberly F.

    2016-01-01

    Many biological processes involve the mechanistic/mammalian target of rapamycin complex 1 (mTORC1). Thus, the challenge of deciphering mTORC1-mediated functions during normal and pathological states in the central nervous system is challenging. Because mTORC1 is at the core of translation, we have investigated mTORC1 function in global and regional protein expression. Activation of mTORC1 has been generally regarded to promote translation. Few but recent works have shown that suppression of mTORC1 can also promote local protein synthesis. Moreover, excessive mTORC1 activation during diseased states represses basal and activity-induced protein synthesis. To determine the role of mTORC1 activation in protein expression, we have used an unbiased, large-scale proteomic approach. We provide evidence that a brief repression of mTORC1 activity in vivo by rapamycin has little effect globally, yet leads to a significant remodeling of synaptic proteins, in particular those proteins that reside in the postsynaptic density. We have also found that curtailing the activity of mTORC1 bidirectionally alters the expression of proteins associated with epilepsy, Alzheimer's disease, and autism spectrum disorder—neurological disorders that exhibit elevated mTORC1 activity. Through a protein–protein interaction network analysis, we have identified common proteins shared among these mTORC1-related diseases. One such protein is Parkinson protein 7, which has been implicated in Parkinson's disease, yet not associated with epilepsy, Alzheimers disease, or autism spectrum disorder. To verify our finding, we provide evidence that the protein expression of Parkinson protein 7, including new protein synthesis, is sensitive to mTORC1 inhibition. Using a mouse model of tuberous sclerosis complex, a disease that displays both epilepsy and autism spectrum disorder phenotypes and has overactive mTORC1 signaling, we show that Parkinson protein 7 protein is elevated in the dendrites and

  12. Rapamycin-insensitive mTORC1 activity controls eIF4E:4E-BP1 binding [v1; ref status: indexed, http://f1000r.es/NM6hpo

    Directory of Open Access Journals (Sweden)

    Mark Livingstone

    2012-07-01

    Full Text Available The recent development of mammalian target of rapamycin (mTOR kinase domain inhibitors and genetic dissection of rapamycin-sensitive and -insensitive mTOR protein complexes (mTORC1 and mTORC2 have revealed that phosphorylation of the mTOR substrate 4E-BP1 on amino acids Thr37 and/or Thr46 represents a rapamycin-insensitive activity of mTORC1. Despite numerous previous reports utilizing serine (Ser-to-alanine (Ala and threonine (Thr-to-Ala phosphorylation site mutants of 4E-BP1 to assess which post-translational modification(s directly regulate binding to eIF4E, an ambiguous understanding persists. This manuscript demonstrates that the initial, rapamycin-insensitive phosphorylation event at Thr46 is sufficient to prevent eIF4E:4E-BP1 binding. This finding is relevant, particularly as mTOR kinase domain inhibitors continue to be assessed for clinical efficacy, since it clarifies a difference between the action of these second-generation mTOR inhibitors and those of rapamycin analogues.

  13. The downregulation of ATG4B mediated by microRNA-34a/34c-5p suppresses rapamycin-induced autophagy.

    Science.gov (United States)

    Wu, Yaran; Dai, Xufang; Ni, Zhenhong; Yan, Xiaojing; He, Fengtian; Lian, Jiqin

    2017-10-01

    Autophagy-related 4B (ATG4B) plays an important role in the process of autophagy induction. However, the molecular events that govern the expression of ATG4B in this process are not well known. Human ATG4B 3'-UTR region (1377 nt) containing miR-34a/miR-34c-5p binding site was amplified by PCR. Luciferase assay was used to assess the activity of reporter genes. Real-time PCR was used to detect the levels of miR-34a and miR-34c-5p. Western blot was used toanalyze the protein levels of ATG4B, LC3 and p62. Both miR-34a and miR-34c-5p could directly target the 3'-UTR of ATG4B mRNA at same site. Overexpression of either miR-34a or miR-34c-5p significantly down-regulated ATG4B at both mRNA and protein levels and this effect can be reversed by ATG4B overexpression. Moreover, Rapamycin-induced autophagy is accompanied with the upregulation of ATG4B and the downregulation of miR-34a/miR-34c-5p. Ectopic expression of either miR-34a or miR-34c-5p markedly suppressed rapamycin-triggered autophagy. In the present study, we found that miR34/ATG4B signaling axis involves in rapamycin-triggered autophagy. This study may provide a new insight for understanding the mechanisms of ATG4B regulation and autophagy induction.

  14. Mammalian Target of Rapamycin Inhibitor Induced Complete Remission of a Recurrent Subependymal Giant Cell Astrocytoma in a Patient Without Features of Tuberous Sclerosis Complex.

    Science.gov (United States)

    Appalla, Deepika; Depalma, Andres; Calderwood, Stanley

    2016-07-01

    The majority of patients with subependymal giant cell astrocytoma (SEGA) have tuberous sclerosis complex (TSC). In such patients, the mammalian target of rapamycin (mTOR) inhibitor everolimus has been shown to induce responses. Isolated SEGA have been reported in patients without clinical or genetic features of TSC. The treatment of these patients with everolimus has not previously been reported. We treated a patient with a recurrent isolated SEGA with an mTOR inhibitor. The patient tolerated therapy well and had a sustained complete remission. MTOR inhibitors may be useful for the treatment of isolated SEGA. Further study is warranted. © 2016 Wiley Periodicals, Inc.

  15. Immunohistochemical analysis of phosphorylated mammalian target of rapamycin and its downstream signaling components in invasive breast cancer.

    Science.gov (United States)

    Ma, Bin-Lin; Shan, Mei-Hui; Sun, Gang; Ren, Guang-Hui; Dong, Chao; Yao, Xuemei; Zhou, Mei

    2015-10-01

    The present study aimed to investigate whether the mammalian target of rapamycin (mTOR) signaling pathway is activated in invasive breast cancer. The expression levels of phosphorylated (p)‑mTOR at ser2448 were detected, as well as the expression levels of its downstream signaling molecules: Eukaryotic translation initiation factor 4E‑binding protein 1 (4E‑BP1), and p70 ribosomal protein S6 kinase 1 (S6K1). The correlation between p‑mTOR, p‑4E‑BP1, p‑S6K1, and the clinicopathological parameters of breast cancer were also determined. p‑mTOR, p‑4E‑BP1 and p‑S6K1 expression was detected in 285 breast cancer tumor samples and adjacent normal tissue samples using immunohistochemistry. The expression levels and the location of the proteins were analyzed and compared in the various tissue samples. Multivariate Cox regression was used to analyze the clinicopathological factors and prognosis associated with the tissue samples. The disease‑free survival rate was examined using survival analyses and Log‑rank tests. The results of the present study indicated that the expression levels of p‑mTOR, p‑4E‑BP1, and p‑S6K1 were significantly higher in breast cancer tissue, as compared with normal tissue (Pbreast cancer tissue samples, as compared with normal tissue samples (P0.05). Thus suggesting that these markers are not adequate risk factors for disease free survival (P>0.05). In conclusion, the results of the present study suggested that p‑mTOR, p‑4E‑BP1, and p‑S6K1 are activated in invasive breast cancer. In addition, the exclusive expression of p‑4E‑BP1 and p‑S6K1 in the cytoplasm may be characteristic of progressive breast cancer. However, p‑mTOR, p‑4E‑BP1, and p‑S6K1 are not prognostic factors for breast cancer.

  16. Mammalian target of rapamycin complex 1 activation sensitizes human glioma cells to hypoxia-induced cell death.

    Science.gov (United States)

    Thiepold, Anna-Luisa; Lorenz, Nadja I; Foltyn, Martha; Engel, Anna L; Divé, Iris; Urban, Hans; Heller, Sonja; Bruns, Ines; Hofmann, Ute; Dröse, Stefan; Harter, Patrick N; Mittelbronn, Michel; Steinbach, Joachim P; Ronellenfitsch, Michael W

    2017-10-01

    Glioblastomas are characterized by fast uncontrolled growth leading to hypoxic areas and necrosis. Signalling from EGFR via mammalian target of rapamycin complex 1 (mTORC1) is a major driver of cell growth and proliferation and one of the most commonly altered signalling pathways in glioblastomas. Therefore, epidermal growth factor receptor and mTORC1 signalling are plausible therapeutic targets and clinical trials with inhibitors are in progress. However, we have previously shown that epidermal growth factor receptor and mTORC1 inhibition triggers metabolic changes leading to adverse effects under the conditions of the tumour microenvironment by protecting from hypoxia-induced cell death. We hypothesized that conversely mTORC1 activation sensitizes glioma cells to hypoxia-induced cell death. As a model for mTORC1 activation we used gene suppression of its physiological inhibitor TSC2 (TSC2sh). TSC2sh glioma cells showed increased sensitivity to hypoxia-induced cell death that was accompanied by an earlier ATP depletion and an increase in reactive oxygen species. There was no difference in extracellular glucose consumption but an altered intracellular metabolic profile with an increase of intermediates of the pentose phosphate pathway. Mechanistically, mTORC1 upregulated the first and rate limiting enzyme of the pentose phosphate pathway, G6PD. Furthermore, an increase in oxygen consumption in TSC2sh cells was detected. This appeared to be due to higher transcription rates of genes involved in mitochondrial respiratory function including PPARGC1A and PPARGC1B (also known as PGC-1α and -β). The finding that mTORC1 activation causes an increase in oxygen consumption and renders malignant glioma cells susceptible to hypoxia and nutrient deprivation could help identify glioblastoma patient cohorts more likely to benefit from hypoxia-inducing therapies such as the VEGFA-targeting antibody bevacizumab in future clinical evaluations. © The Author (2017). Published by

  17. Mechanistic target of rapamycin is necessary for changes in dendritic spine morphology associated with long-term potentiation.

    Science.gov (United States)

    Henry, Fredrick E; Hockeimer, William; Chen, Alex; Mysore, Shreesh P; Sutton, Michael A

    2017-10-30

    Alterations in the strength of excitatory synapses in the hippocampus is believed to serve a vital function in the storage and recall of new information in the mammalian brain. These alterations involve the regulation of both functional and morphological features of dendritic spines, the principal sites of excitatory synaptic contact. New protein synthesis has been implicated extensively in the functional changes observed following long-term potentiation (LTP), and changes to spine morphology have similarly been documented extensively following synaptic potentiation. However, mechanistic links between de novo translation and the structural changes of potentiated spines are less clear. Here, we assess explicitly the potential contribution of new protein translation under control of the mechanistic target of rapamycin (mTOR) to LTP-associated changes in spine morphology. Utilizing genetic and pharmacological manipulations of mTORC1 function in combination with confocal microscopy in live dissociated hippocampal cultures, we demonstrate that chemically-induced LTP (cLTP) requires do novo protein synthesis and intact mTORC1 signaling. We observed a striking diversity in response properties across morphological classes, with mushroom spines displaying a particular sensitivity to altered mTORC1 signaling across varied levels of synaptic activity. Notably, while pharmacological inhibition of mTORC1 signaling significantly diminished glycine-induced changes in spine morphology, transient genetic upregulation of mTORC1 signaling was insufficient to produce spine enlargements on its own. In contrast, genetic upregulation of mTORC1 signaling promoted rapid expansion in spine head diameter when combined with otherwise sub-threshold synaptic stimulation. These results suggest that synaptic activity-derived signaling pathways act in combination with mTORC1-dependent translational control mechanisms to ultimately regulate changes in spine morphology. As several monogenic

  18. Antitumor efficacy profile of PKI-402, a dual phosphatidylinositol 3-kinase/mammalian target of rapamycin inhibitor.

    Science.gov (United States)

    Mallon, Robert; Hollander, Irwin; Feldberg, Larry; Lucas, Judy; Soloveva, Veronica; Venkatesan, Aranapakam; Dehnhardt, Christoph; Delos Santos, Efren; Chen, Zecheng; Dos Santos, Osvaldo; Ayral-Kaloustian, Semiramis; Gibbons, Jay

    2010-04-01

    PKI-402 is a selective, reversible, ATP-competitive, equipotent inhibitor of class I phosphatidylinositol 3-kinases (PI3K), including PI3K-alpha mutants, and mammalian target of rapamycin (mTOR; IC(50) versus PI3K-alpha = 2 nmol/L). PKI-402 inhibited growth of human tumor cell lines derived from breast, brain (glioma), pancreas, and non-small cell lung cancer tissue and suppressed phosphorylation of PI3K and mTOR effector proteins (e.g., Akt at T308) at concentrations that matched those that inhibited cell growth. In MDA-MB-361 [breast: Her2(+) and PIK3CA mutant (E545K)], 30 nmol/L PKI-402 induced cleaved poly(ADP-ribose) polymerase (PARP), a marker for apoptosis. In vivo, PKI-402 inhibited tumor growth in MDA-MB-361, glioma (U87MG), and lung (A549) xenograft models. In MDA-MB-361, PKI-402 at 100 mg/kg (daily for 5 days, one round) reduced initial tumor volume of 260 mm(3) to 129 mm(3) and prevented tumor regrowth for 70 days. In MDA-MB-361 tumors, PKI-402 (100 mg/kg, single dose) suppressed Akt phosphorylation (at T308) and induced cleaved PARP. Suppression of phosphorylated Akt (p-Akt) was complete at 8 hours and still evident at 24 hours. Cleaved PARP was evident at 8 and 24 hours. In normal tissue (heart and lung), PKI-402 (100 mg/kg) had minimal effect on p-Akt, with no detectable cleaved PARP. Preferential accumulation of PKI-402 in tumor tissue was observed. Complete, sustained suppression of Akt phosphorylation may cause tumor regression in MDA-MB-361 and other xenograft models. We are testing whether dual PI3K/mTOR inhibitors can durably suppress p-Akt, induce cleaved PARP, and cause tumor regression in a diverse set of human tumor xenograft models. Mol Cancer Ther; 9(4); 976-84. (c)2010 AACR.

  19. Mammalian target of rapamycin signaling and ubiquitin proteasome-related gene expression in 3 different skeletal muscles of colostrum- versus formula-fed calves.

    Science.gov (United States)

    Sadri, H; Steinhoff-Wagner, J; Hammon, Harald M; Bruckmaier, R M; Görs, S; Sauerwein, H

    2017-11-01

    The rates of protein turnover are higher during the neonatal period than at any other time in postnatal life. The mammalian target of rapamycin (mTOR) and the ubiquitin-proteasome system are key pathways regulating cellular protein turnover. The objectives of this study were (1) to elucidate the effect of feeding colostrum versus milk-based formula on the mRNA abundance of key components of the mTOR pathway and of the ubiquitin-proteasome system in skeletal muscle of neonatal calves and (2) to compare different muscles. German Holstein calves were fed either colostrum (COL; n = 7) or milk-based formula (FOR; n = 7) up to 4 d of life. The nutrient content in formula and colostrum was similar, but formula had lower concentrations of free branched-chain AA (BCAA) and free total AA, insulin, and insulin-like growth factor (IGF)-I than colostrum. Blood samples were taken from d 1 to 4 before morning feeding and before and 2 h after the last feeding on d 4. Muscle samples from M. longissimus dorsi (MLD), M. semitendinosus (MST), and M. masseter (MM) were collected after slaughter on d 4 at 2 h after feeding. The preprandial concentrations of free total AA and BCAA, insulin, and IGF-I in plasma changed over time but did not differ between groups. Plasma free total AA and BCAA concentrations decreased in COL, whereas they increased in FOR after feeding, resulting in higher postprandial plasma total AA and BCAA concentrations in FOR than in COL. Plasma insulin concentrations increased after feeding in both groups but were higher in COL than in FOR. Plasma IGF-I concentrations decreased in COL, whereas they remained unchanged in FOR after feeding. The mRNA abundance of mTOR and ribosomal protein S6 kinase 1 (S6K1) in 3 different skeletal muscles was greater in COL than in FOR, whereas that of eukaryotic translation initiation factor 4E binding protein 1 (4EBP1) was unaffected by diet. The mRNA abundance of ubiquitin activating enzyme (UBA1) and ubiquitin conjugating enzyme 1

  20. In vitro and in vivo degradation of rapamycin-eluting Mg-Nd-Zn-Zr alloy stents in porcine coronary arteries.

    Science.gov (United States)

    Shi, Yongjuan; Zhang, Lei; Chen, Jiahui; Zhang, Jian; Yuan, Feng; Shen, Li; Chen, Chenxin; Pei, Jia; Li, Zhonghua; Tan, Jinyun; Yuan, Guangyin

    2017-11-01

    In this work, rapamycin-eluting poly (d, l-lactic acid) coating (PDLLA/RAPA) was prepared on biodegradable Mg-Nd-Zn-Zr alloy (JDBM) for both in vitro and in vivo investigation of the degradation behaviors of the magnesium alloy stent platform. Electrochemical tests and hydrogen evolution test demonstrated significant in vitro protection of the polymeric coating against magnesium degradation both in short and long term. The 3-month in vivo study on the RAPA-eluting JDBM stent implanted into porcine coronary arteries confirmed its favorable safety, and in the meanwhile revealed similar neointima proliferation compared to the second generation DES Firebird 2 with no occurrence of adverse complications. Moreover, Micro-CT examination combined with IVUS and OCT detection indicated a remarkably lower degradation rate and prolonged radial supporting duration of the drug-eluting JDBM stent as compared to the bare, attributable to the protection of the coating in vivo. Hence, rapamycin-eluting JDBM stents exhibit great potential for clinical application. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Inhibition of Mammalian Target of Rapamycin Complex 1 (mTORC1 Downregulates ELOVL1 Gene Expression and Fatty Acid Synthesis in Goat Fetal Fibroblasts

    Directory of Open Access Journals (Sweden)

    Weipeng Wang

    2015-07-01

    Full Text Available Elongation of very-long-chain fatty acids 1 (ELOVL1 is a ubiquitously expressed gene that belongs to the ELOVL family and regulates the synthesis of very-long-chain fatty acids (VLCFAs and sphingolipids, from yeast to mammals. Mammalian target of rapamycin complex 1 (mTORC1 is a central regulator of cell metabolism and is associated with fatty acids synthesis. In this study, we cloned the cDNA that encodes Cashmere goat (Capra hircus ELOVL1 (GenBank Accession number KF549985 and investigated its expression in 10 tissues. ELOVL1 cDNA was 840 bp, encoding a deduced protein of 279 amino acids, and ELOVL1 mRNA was expressed in a wide range of tissues. Inhibition of mTORC1 by rapamycin decreased ELOVL1 expression and fatty acids synthesis in Cashmere goat fetal fibroblasts. These data show that ELOVL1 expression is regulated by mTORC1 and that mTORC1 has significant function in fatty acids synthesis in Cashmere goat.

  2. mTOR inhibitor rapamycin induce polymorphonuclear myeloid-derived suppressor cells mobilization and function in protecting against acute graft-versus-host disease after bone marrow transplantation.

    Science.gov (United States)

    Lin, Yu; Wang, Binsheng; Shan, Wei; Tan, Yamin; Feng, Jingjing; Xu, Lin; Wang, Limengmeng; Han, Biqing; Zhang, Mingming; Yu, Jian; Yu, Xiaohong; Huang, He

    2017-11-10

    The mammalian target of rapamycin (mTOR) inhibitor rapamycin (RAPA) has been shown to be an effective immunosuppressor in the management of acute graft-versus-host disease (aGVHD) after bone marrow transplantation. Myeloid-derived suppressor cells (MDSCs) also have a protective effect in aGVHD regulation. However, the relationship between RAPA and MDSCs in aGVHD models is unclear. Meanwhile, the effect of RAPA on different subgroups of MDSCs is also less well described. In this study, we demonstrate that in vivo administration of RAPA results in the expansion and functional enhancement of polymorphonuclear MDSCs (PMN-MDSCs) in a murine model of aGVHD. RAPA treatment can enhance the suppressive function of PMN-MDSCs via up-regulation of arginase1 (Arg1) and induced nitric oxide synthase (iNOS) at later time points. Moreover, RAPA can also induce a strong immunosuppressive function in PMN-MDSCs from murine bone marrow in vitro, but has a contrary effect on monocytic MDSCs (M-MDSCs). We found that RAPA-treated PMN-MDSCs can restrain the differentiation of Th1/Th2 cells and promote induction of regulatory T cells in in vitro studies. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Retraction Statement: 'MicroRNA-218 increases cellular sensitivity to Rapamycin via targeting Rictor in cervical cancer' by Li J, Wang J, Wang Y, Qiu H.

    Science.gov (United States)

    2017-02-01

    The above article from APMIS, published online on 24 April 2015 in Wiley Online Library (wileyonlinelibrary.com) and in Volume 123, pp. 562-570, has been retracted by agreement between the authors, the journal Editors in Chief, Professors Bodil Norrild, Ben Vainer and Elisabeth Ralfkiaer, and John Wiley & Sons Ltd. The article has been retracted due to errors in the reported results. In this study, the authors used HeLa and SiHa cell lines to investigate the biological roles of miR-218. However, subsequently it emerged that the two cell lines were contaminated in the laboratory by other unknown cell lines. When repeating the experiments, it was found that the functions of miR-218 were not as significant as had been previously reported, especially its effects on rapamycin sensitivity. Reference Li J, Li X, Wang J, Wang Y, Qiu H. MicroRNA-218 increases cellular sensitivity to Rapamycin via targeting Rictor in cervical cancer. APMIS 2015; 123:562-570. doi: 10.1111/apm.12387. © 2016 APMIS. Published by John Wiley & Sons Ltd.

  4. Comparison of three rapamycin dosing schedules in A/J Tsc2+/- mice and improved survival with angiogenesis inhibitor or asparaginase treatment in mice with subcutaneous tuberous sclerosis related tumors

    Directory of Open Access Journals (Sweden)

    Dabora Sandra L

    2010-02-01

    Full Text Available Abstract Background Tuberous Sclerosis Complex (TSC is an autosomal dominant tumor disorder characterized by the growth of hamartomas in various organs including the kidney, brain, skin, lungs, and heart. Rapamycin has been shown to reduce the size of kidney angiomyolipomas associated with TSC; however, tumor regression is incomplete and kidney angiomyolipomas regrow after cessation of treatment. Mouse models of TSC2 related tumors are useful for evaluating new approaches to drug therapy for TSC. Methods In cohorts of Tsc2+/- mice, we compared kidney cystadenoma severity in A/J and C57BL/6 mouse strains at both 9 and 12 months of age. We also investigated age related kidney tumor progression and compared three different rapamycin treatment schedules in cohorts of A/J Tsc2+/- mice. In addition, we used nude mice bearing Tsc2-/- subcutaneous tumors to evaluate the therapeutic utility of sunitinib, bevacizumab, vincristine, and asparaginase. Results TSC related kidney disease severity is 5-10 fold higher in A/J Tsc2+/- mice compared with C57BL/6 Tsc2+/- mice. Similar to kidney angiomyolipomas associated with TSC, the severity of kidne