WorldWideScience

Sample records for suppresses mtorc1 signaling

  1. Ursolic acid inhibits leucine-stimulated mTORC1 signaling by suppressing mTOR localization to lysosome.

    Directory of Open Access Journals (Sweden)

    Xiang Ou

    Full Text Available Ursolic acid (UA, a pentacyclic triterpenoid widely found in medicinal herbs and fruits, has been reported to possess a wide range of beneficial properties including anti-hyperglycemia, anti-obesity, and anti-cancer. However, the molecular mechanisms underlying the action of UA remain largely unknown. Here we show that UA inhibits leucine-induced activation of the mechanistic target of rapamycin complex 1 (mTORC1 signaling pathway in C2C12 myotubes. The UA-mediated inhibition of mTORC1 is independent of Akt, tuberous sclerosis complex 1/2 (TSC1/2, and Ras homolog enriched in brain (Rheb, suggesting that UA negatively regulates mTORC1 signaling by targeting at a site downstream of these mTOR regulators. UA treatment had no effect on the interaction between mTOR and its activator Raptor or inhibitor Deptor, but suppressed the binding of RagB to Raptor and inhibited leucine-induced mTOR lysosomal localization. Taken together, our study identifies UA as a direct negative regulator of the mTORC1 signaling pathway and suggests a novel mechanism by which UA exerts its beneficial function.

  2. Sestrin2 Suppresses Classically Activated Macrophages-Mediated Inflammatory Response in Myocardial Infarction through Inhibition of mTORC1 Signaling

    Directory of Open Access Journals (Sweden)

    Keping Yang

    2017-06-01

    Full Text Available Myocardial infarction (MI triggers an intense inflammatory response that is essential for dead tissue clearance but also detrimental to cardiac repair. Macrophages are active and critical players in the inflammatory response after MI. Understanding the molecular mechanisms by which macrophage-mediated inflammatory response is regulated is important for designing new therapeutic interventions for MI. In the current study, we examined the role of Sestrin2, which is a stress-inducible protein that regulate metabolic homeostasis, in the regulation of inflammatory response of cardiac macrophages after MI. We found that cardiac macrophages upregulated Sestrin2 expression in a mouse MI model. Using a lentiviral transduction system to overexpress Sestrin2 in polarized M1 and M2 macrophages, we revealed that Sestrin2 predominantly functioned on M1 rather than M2 macrophages. Sestrin2 overexpression suppressed inflammatory response of M1 macrophages both in vitro and in vivo. Furthermore, in the mouse MI model with selective depletion of endogenous macrophages and adoptive transfer of exogenous Sestrin2-overexpressing macrophages, the anti-inflammatory and repair-promoting effect of Sestrin2-overexpressing macrophages was demonstrated. Furthermore, Sestrin2 significantly inhibited mTORC1 signaling in M1 macrophages. Taken together, our study indicates the importance of Sestrin2 for suppression of M1 macrophage-mediated cardiac inflammation after MI.

  3. Differential response of skeletal muscles to mTORC1 signaling during atrophy and hypertrophy.

    Science.gov (United States)

    Bentzinger, C Florian; Lin, Shuo; Romanino, Klaas; Castets, Perrine; Guridi, Maitea; Summermatter, Serge; Handschin, Christoph; Tintignac, Lionel A; Hall, Michael N; Rüegg, Markus A

    2013-03-06

    Skeletal muscle mass is determined by the balance between protein synthesis and degradation. Mammalian target of rapamycin complex 1 (mTORC1) is a master regulator of protein translation and has been implicated in the control of muscle mass. Inactivation of mTORC1 by skeletal muscle-specific deletion of its obligatory component raptor results in smaller muscles and a lethal dystrophy. Moreover, raptor-deficient muscles are less oxidative through changes in the expression PGC-1α, a critical determinant of mitochondrial biogenesis. These results suggest that activation of mTORC1 might be beneficial to skeletal muscle by providing resistance to muscle atrophy and increasing oxidative function. Here, we tested this hypothesis by deletion of the mTORC1 inhibitor tuberous sclerosis complex (TSC) in muscle fibers. Skeletal muscles of mice with an acute or a permanent deletion of raptor or TSC1 were examined using histological, biochemical and molecular biological methods. Response of the muscles to changes in mechanical load and nerve input was investigated by ablation of synergistic muscles or by denervation . Genetic deletion or knockdown of raptor, causing inactivation of mTORC1, was sufficient to prevent muscle growth and enhance muscle atrophy. Conversely, short-term activation of mTORC1 by knockdown of TSC induced muscle fiber hypertrophy and atrophy-resistance upon denervation, in both fast tibialis anterior (TA) and slow soleus muscles. Surprisingly, however, sustained activation of mTORC1 by genetic deletion of Tsc1 caused muscle atrophy in all but soleus muscles. In contrast, oxidative capacity was increased in all muscles examined. Consistently, TSC1-deficient soleus muscle was atrophy-resistant whereas TA underwent normal atrophy upon denervation. Moreover, upon overloading, plantaris muscle did not display enhanced hypertrophy compared to controls. Biochemical analysis indicated that the atrophy response of muscles was based on the suppressed phosphorylation

  4. Differential response of skeletal muscles to mTORC1 signaling during atrophy and hypertrophy

    Science.gov (United States)

    2013-01-01

    suppressed phosphorylation of PKB/Akt via feedback inhibition by mTORC1 and subsequent increased expression of the E3 ubiquitin ligases MuRF1 and atrogin-1/MAFbx. In contrast, expression of both E3 ligases was not increased in soleus muscle suggesting the presence of compensatory mechanisms in this muscle. Conclusions Our study shows that the mTORC1- and the PKB/Akt-FoxO pathways are tightly interconnected and differentially regulated depending on the muscle type. These results indicate that long-term activation of the mTORC1 signaling axis is not a therapeutic option to promote muscle growth because of its strong feedback induction of the E3 ubiquitin ligases involved in protein degradation. PMID:23497627

  5. STRADalpha deficiency results in aberrant mTORC1 signaling during corticogenesis in humans and mice.

    Science.gov (United States)

    Orlova, Ksenia A; Parker, Whitney E; Heuer, Gregory G; Tsai, Victoria; Yoon, Jason; Baybis, Marianna; Fenning, Robert S; Strauss, Kevin; Crino, Peter B

    2010-05-01

    Polyhydramnios, megalencephaly, and symptomatic epilepsy syndrome (PMSE) is a rare human autosomal-recessive disorder characterized by abnormal brain development, cognitive disability, and intractable epilepsy. It is caused by homozygous deletions of STE20-related kinase adaptor alpha (STRADA). The underlying pathogenic mechanisms of PMSE and the role of STRADA in cortical development remain unknown. Here, we found that a human PMSE brain exhibits cytomegaly, neuronal heterotopia, and aberrant activation of mammalian target of rapamycin complex 1 (mTORC1) signaling. STRADalpha normally binds and exports the protein kinase LKB1 out of the nucleus, leading to suppression of the mTORC1 pathway. We found that neurons in human PMSE cortex exhibited abnormal nuclear localization of LKB1. To investigate this further, we modeled PMSE in mouse neural progenitor cells (mNPCs) in vitro and in developing mouse cortex in vivo by knocking down STRADalpha expression. STRADalpha-deficient mNPCs were cytomegalic and showed aberrant rapamycin-dependent activation of mTORC1 in association with abnormal nuclear localization of LKB1. Consistent with the observations in human PMSE brain, knockdown of STRADalpha in vivo resulted in cortical malformation, enhanced mTORC1 activation, and abnormal nuclear localization of LKB1. Thus, we suggest that the aberrant nuclear accumulation of LKB1 caused by STRADalpha deficiency contributes to hyperactivation of mTORC1 signaling and disruption of neuronal lamination during corticogenesis, and thereby the neurological features associated with PMSE.

  6. STRADα deficiency results in aberrant mTORC1 signaling during corticogenesis in humans and mice

    Science.gov (United States)

    Orlova, Ksenia A.; Parker, Whitney E.; Heuer, Gregory G.; Tsai, Victoria; Yoon, Jason; Baybis, Marianna; Fenning, Robert S.; Strauss, Kevin; Crino, Peter B.

    2010-01-01

    Polyhydramnios, megalencephaly, and symptomatic epilepsy syndrome (PMSE) is a rare human autosomal-recessive disorder characterized by abnormal brain development, cognitive disability, and intractable epilepsy. It is caused by homozygous deletions of STE20-related kinase adaptor α (STRADA). The underlying pathogenic mechanisms of PMSE and the role of STRADA in cortical development remain unknown. Here, we found that a human PMSE brain exhibits cytomegaly, neuronal heterotopia, and aberrant activation of mammalian target of rapamycin complex 1 (mTORC1) signaling. STRADα normally binds and exports the protein kinase LKB1 out of the nucleus, leading to suppression of the mTORC1 pathway. We found that neurons in human PMSE cortex exhibited abnormal nuclear localization of LKB1. To investigate this further, we modeled PMSE in mouse neural progenitor cells (mNPCs) in vitro and in developing mouse cortex in vivo by knocking down STRADα expression. STRADα-deficient mNPCs were cytomegalic and showed aberrant rapamycin-dependent activation of mTORC1 in association with abnormal nuclear localization of LKB1. Consistent with the observations in human PMSE brain, knockdown of STRADα in vivo resulted in cortical malformation, enhanced mTORC1 activation, and abnormal nuclear localization of LKB1. Thus, we suggest that the aberrant nuclear accumulation of LKB1 caused by STRADα deficiency contributes to hyperactivation of mTORC1 signaling and disruption of neuronal lamination during corticogenesis, and thereby the neurological features associated with PMSE. PMID:20424326

  7. CGEF-1 regulates mTORC1 signaling during adult longevity and stress response in

    NARCIS (Netherlands)

    Li, Yujie; Finkbeiner, Sandra; Ganner, Athina; Gerber, Julia; Klein, Marinella; Grafe, Manuel; Kandzia, Jakob; Thien, Antje; Thedieck, Kathrin; Breves, Gerhard; Jank, Thomas; Baumeister, Ralf; Walz, Gerd; Neumann-Haefelin, Elke

    2018-01-01

    The mechanistic target of rapamycin (mTOR) kinase is central to metabolism and growth, and has a conserved role in aging. mTOR functions in two complexes, mTORC1 and mTORC2. In diverse eukaryotes, inhibition of mTORC1 signaling increases lifespan. mTORC1 transduces anabolic signals to stimulate

  8. Aspirin suppresses growth in PI3K-mutant breast cancer by activating AMPK and inhibiting mTORC1 signaling

    Science.gov (United States)

    Henry, Whitney S.; Laszewski, Tyler; Tsang, Tiffany; Beca, Francisco; Beck, Andrew H.; McAllister, Sandra S.; Toker, Alex

    2016-01-01

    Despite the high incidence of oncogenic mutations in PIK3CA, the gene encoding the catalytic subunit of phosphoinositide 3-kinase (PI3K), PI3K inhibitors have yielded little clinical benefit for breast cancer patients. Recent epidemiological studies have suggested a therapeutic benefit from aspirin intake in cancers harboring oncogenic PIK3CA. Here we show that mutant PIK3CA-expressing breast cancer cells have greater sensitivity to aspirin-mediated growth suppression than their wild-type counterparts. Aspirin decreased viability and anchorage-independent growth of mutant PIK3CA breast cancer cells independently of its effects on cyclooxygenase-2 (COX-2) and nuclear factor-kappa B (NF-κB). We ascribed the effects of aspirin to AMP-activated protein kinase (AMPK) activation, mammalian target of rapamycin complex 1 (mTORC1) inhibition, and autophagy induction. In vivo, oncogenic PIK3CA-driven mouse mammary tumors treated daily with aspirin resulted in decreased tumor growth kinetics, while combination therapy of aspirin and a PI3K inhibitor further attenuated tumor growth. Our study supports evaluation of aspirin and PI3K pathway inhibitors as combination therapy for targeting breast cancer. PMID:27940576

  9. The impact of cow's milk-mediated mTORC1-signaling in the initiation and progression of prostate cancer.

    Science.gov (United States)

    Melnik, Bodo C; John, Swen Malte; Carrera-Bastos, Pedro; Cordain, Loren

    2012-08-14

    Prostate cancer (PCa) is dependent on androgen receptor signaling and aberrations of the PI3K-Akt-mTORC1 pathway mediating excessive and sustained growth signaling. The nutrient-sensitive kinase mTORC1 is upregulated in nearly 100% of advanced human PCas. Oncogenic mTORC1 signaling activates key subsets of mRNAs that cooperate in distinct steps of PCa initiation and progression. Epidemiological evidence points to increased dairy protein consumption as a major dietary risk factor for the development of PCa. mTORC1 is a master regulator of protein synthesis, lipid synthesis and autophagy pathways that couple nutrient sensing to cell growth and cancer. This review provides evidence that PCa initiation and progression are promoted by cow´s milk, but not human milk, stimulation of mTORC1 signaling. Mammalian milk is presented as an endocrine signaling system, which activates mTORC1, promotes cell growth and proliferation and suppresses autophagy. Naturally, milk-mediated mTORC1 signaling is restricted only to the postnatal growth phase of mammals. However, persistent consumption of cow´s milk proteins in humans provide highly insulinotropic branched-chain amino acids (BCAAs) provided by milk´s fast hydrolysable whey proteins, which elevate postprandial plasma insulin levels, and increase hepatic IGF-1 plasma concentrations by casein-derived amino acids. BCAAs, insulin and IGF-1 are pivotal activating signals of mTORC1. Increased cow´s milk protein-mediated mTORC1 signaling along with constant exposure to commercial cow´s milk estrogens derived from pregnant cows may explain the observed association between high dairy consumption and increased risk of PCa in Westernized societies. As well-balanced mTORC1-signaling plays an important role in appropriate prostate morphogenesis and differentiation, exaggerated mTORC1-signaling by high cow´s milk consumption predominantly during critical growth phases of prostate development and differentiation may exert long

  10. The impact of cow's milk-mediated mTORC1-signaling in the initiation and progression of prostate cancer

    Directory of Open Access Journals (Sweden)

    Melnik Bodo C

    2012-08-01

    Full Text Available Abstract Prostate cancer (PCa is dependent on androgen receptor signaling and aberrations of the PI3K-Akt-mTORC1 pathway mediating excessive and sustained growth signaling. The nutrient-sensitive kinase mTORC1 is upregulated in nearly 100% of advanced human PCas. Oncogenic mTORC1 signaling activates key subsets of mRNAs that cooperate in distinct steps of PCa initiation and progression. Epidemiological evidence points to increased dairy protein consumption as a major dietary risk factor for the development of PCa. mTORC1 is a master regulator of protein synthesis, lipid synthesis and autophagy pathways that couple nutrient sensing to cell growth and cancer. This review provides evidence that PCa initiation and progression are promoted by cow´s milk, but not human milk, stimulation of mTORC1 signaling. Mammalian milk is presented as an endocrine signaling system, which activates mTORC1, promotes cell growth and proliferation and suppresses autophagy. Naturally, milk-mediated mTORC1 signaling is restricted only to the postnatal growth phase of mammals. However, persistent consumption of cow´s milk proteins in humans provide highly insulinotropic branched-chain amino acids (BCAAs provided by milk´s fast hydrolysable whey proteins, which elevate postprandial plasma insulin levels, and increase hepatic IGF-1 plasma concentrations by casein-derived amino acids. BCAAs, insulin and IGF-1 are pivotal activating signals of mTORC1. Increased cow´s milk protein-mediated mTORC1 signaling along with constant exposure to commercial cow´s milk estrogens derived from pregnant cows may explain the observed association between high dairy consumption and increased risk of PCa in Westernized societies. As well-balanced mTORC1-signaling plays an important role in appropriate prostate morphogenesis and differentiation, exaggerated mTORC1-signaling by high cow´s milk consumption predominantly during critical growth phases of prostate development and

  11. The impact of cow's milk-mediated mTORC1-signaling in the initiation and progression of prostate cancer

    Science.gov (United States)

    2012-01-01

    Prostate cancer (PCa) is dependent on androgen receptor signaling and aberrations of the PI3K-Akt-mTORC1 pathway mediating excessive and sustained growth signaling. The nutrient-sensitive kinase mTORC1 is upregulated in nearly 100% of advanced human PCas. Oncogenic mTORC1 signaling activates key subsets of mRNAs that cooperate in distinct steps of PCa initiation and progression. Epidemiological evidence points to increased dairy protein consumption as a major dietary risk factor for the development of PCa. mTORC1 is a master regulator of protein synthesis, lipid synthesis and autophagy pathways that couple nutrient sensing to cell growth and cancer. This review provides evidence that PCa initiation and progression are promoted by cow´s milk, but not human milk, stimulation of mTORC1 signaling. Mammalian milk is presented as an endocrine signaling system, which activates mTORC1, promotes cell growth and proliferation and suppresses autophagy. Naturally, milk-mediated mTORC1 signaling is restricted only to the postnatal growth phase of mammals. However, persistent consumption of cow´s milk proteins in humans provide highly insulinotropic branched-chain amino acids (BCAAs) provided by milk´s fast hydrolysable whey proteins, which elevate postprandial plasma insulin levels, and increase hepatic IGF-1 plasma concentrations by casein-derived amino acids. BCAAs, insulin and IGF-1 are pivotal activating signals of mTORC1. Increased cow´s milk protein-mediated mTORC1 signaling along with constant exposure to commercial cow´s milk estrogens derived from pregnant cows may explain the observed association between high dairy consumption and increased risk of PCa in Westernized societies. As well-balanced mTORC1-signaling plays an important role in appropriate prostate morphogenesis and differentiation, exaggerated mTORC1-signaling by high cow´s milk consumption predominantly during critical growth phases of prostate development and differentiation may exert long

  12. Dietary intervention in acne: Attenuation of increased mTORC1 signaling promoted by Western diet.

    Science.gov (United States)

    Melnik, Bodo

    2012-01-01

    The purpose of this paper is to highlight the endocrine signaling of Western diet, a fundamental environmental factor involved in the pathogenesis of epidemic acne. Western nutrition is characterized by high calorie uptake, high glycemic load, high fat and meat intake, as well as increased consumption of insulin- and IGF-1-level elevating dairy proteins. Metabolic signals of Western diet are sensed by the nutrient-sensitive kinase, mammalian target of rapamycin complex 1 (mTORC1), which integrates signals of cellular energy, growth factors (insulin, IGF-1) and protein-derived signals, predominantly leucine, provided in high amounts by milk proteins and meat. mTORC1 activates SREBP, the master transcription factor of lipogenesis. Leucine stimulates mTORC1-SREBP signaling and leucine is directly converted by sebocytes into fatty acids and sterols for sebaceous lipid synthesis. Over-activated mTORC1 increases androgen hormone secretion and most likely amplifies androgen-driven mTORC1 signaling of sebaceous follicles. Testosterone directly activates mTORC1. Future research should investigate the effects of isotretinoin on sebocyte mTORC1 activity. It is conceivable that isotretinoin may downregulate mTORC1 in sebocytes by upregulation of nuclear levels of FoxO1. The role of Western diet in acne can only be fully appreciated when all stimulatory inputs for maximal mTORC1 activation, i.e., glucose, insulin, IGF-1 and leucine, are adequately considered. Epidemic acne has to be recognized as an mTORC1-driven disease of civilization like obesity, type 2 diabetes, cancer and neurodegenerative diseases. These new insights into Western diet-mediated mTORC1-hyperactivity provide a rational basis for dietary intervention in acne by attenuating mTORC1 signaling by reducing (1) total energy intake, (2) hyperglycemic carbohydrates, (3) insulinotropic dairy proteins and (4) leucine-rich meat and dairy proteins. The necessary dietary changes are opposed to the evolution of

  13. Screen for chemical modulators of autophagy reveals novel therapeutic inhibitors of mTORC1 signaling.

    Directory of Open Access Journals (Sweden)

    Aruna D Balgi

    Full Text Available BACKGROUND: Mammalian target of rapamycin complex 1 (mTORC1 is a protein kinase that relays nutrient availability signals to control numerous cellular functions including autophagy, a process of cellular self-eating activated by nutrient depletion. Addressing the therapeutic potential of modulating mTORC1 signaling and autophagy in human disease requires active chemicals with pharmacologically desirable properties. METHODOLOGY/PRINCIPAL FINDINGS: Using an automated cell-based assay, we screened a collection of >3,500 chemicals and identified three approved drugs (perhexiline, niclosamide, amiodarone and one pharmacological reagent (rottlerin capable of rapidly increasing autophagosome content. Biochemical assays showed that the four compounds stimulate autophagy and inhibit mTORC1 signaling in cells maintained in nutrient-rich conditions. The compounds did not inhibit mTORC2, which also contains mTOR as a catalytic subunit, suggesting that they do not inhibit mTOR catalytic activity but rather inhibit signaling to mTORC1. mTORC1 inhibition and autophagosome accumulation induced by perhexiline, niclosamide or rottlerin were rapidly reversed upon drug withdrawal whereas amiodarone inhibited mTORC1 essentially irreversibly. TSC2, a negative regulator of mTORC1, was required for inhibition of mTORC1 signaling by rottlerin but not for mTORC1 inhibition by perhexiline, niclosamide and amiodarone. Transient exposure of immortalized mouse embryo fibroblasts to these drugs was not toxic in nutrient-rich conditions but led to rapid cell death by apoptosis in starvation conditions, by a mechanism determined in large part by the tuberous sclerosis complex protein TSC2, an upstream regulator of mTORC1. By contrast, transient exposure to the mTORC1 inhibitor rapamycin caused essentially irreversible mTORC1 inhibition, sustained inhibition of cell growth and no selective cell killing in starvation. CONCLUSION/SIGNIFICANCE: The observation that drugs already

  14. Loss of mTORC1 signaling alters pancreatic α cell mass and impairs glucagon secretion

    Science.gov (United States)

    Bozadjieva, Nadejda; Dai, Xiao-Qing; Cummings, Kelsey; Gimeno, Jennifer; Powers, Alvin C.; Gittes, George K.; Rüegg, Markus A.; Hall, Michael N.; MacDonald, Patrick E.

    2017-01-01

    Glucagon plays a major role in the regulation of glucose homeostasis during fed and fasting states. However, the mechanisms responsible for the regulation of pancreatic α cell mass and function are not completely understood. In the current study, we identified mTOR complex 1 (mTORC1) as a major regulator of α cell mass and glucagon secretion. Using mice with tissue-specific deletion of the mTORC1 regulator Raptor in α cells (αRaptorKO), we showed that mTORC1 signaling is dispensable for α cell development, but essential for α cell maturation during the transition from a milk-based diet to a chow-based diet after weaning. Moreover, inhibition of mTORC1 signaling in αRaptorKO mice and in WT animals exposed to chronic rapamycin administration decreased glucagon content and glucagon secretion. In αRaptorKO mice, impaired glucagon secretion occurred in response to different secretagogues and was mediated by alterations in KATP channel subunit expression and activity. Additionally, our data identify the mTORC1/FoxA2 axis as a link between mTORC1 and transcriptional regulation of key genes responsible for α cell function. Thus, our results reveal a potential function of mTORC1 in nutrient-dependent regulation of glucagon secretion and identify a role for mTORC1 in controlling α cell–mass maintenance. PMID:29106387

  15. Novel mTORC1 and 2 Signaling Pathways in Polycystic Kidney Disease (PKD)

    Science.gov (United States)

    2017-09-01

    AWARD NUMBER: W81XWH-16-1-0172 TITLE: Novel mTORC1 and 2 Signaling Pathways in Polycystic Kidney Disease (PKD) PRINCIPAL INVESTIGATOR: Charles...TITLE AND SUBTITLE 5a. CONTRACT NUMBER W81XWH-16-1-0172 Novel mTORC1 and 2 Signaling Pathways in Polycystic Kidney Disease (PKD) 5b. GRANT NUMBER 5c...live PKD mice. 15. SUBJECT TERMS Polycystic kidney disease , PKD, mTORC1, mTORC2, Raptor, Rictor. 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF

  16. Key mediators of intracellular amino acids signaling to mTORC1 activation.

    Science.gov (United States)

    Duan, Yehui; Li, Fengna; Tan, Kunrong; Liu, Hongnan; Li, Yinghui; Liu, Yingying; Kong, Xiangfeng; Tang, Yulong; Wu, Guoyao; Yin, Yulong

    2015-05-01

    Mammalian target of rapamycin complex 1 (mTORC1) is activated by amino acids to promote cell growth via protein synthesis. Specifically, Ras-related guanosine triphosphatases (Rag GTPases) are activated by amino acids, and then translocate mTORC1 to the surface of late endosomes and lysosomes. Ras homolog enriched in brain (Rheb) resides on this surface and directly activates mTORC1. Apart from the presence of intracellular amino acids, Rag GTPases and Rheb, other mediators involved in intracellular amino acid signaling to mTORC1 activation include human vacuolar sorting protein-34 (hVps34) and mitogen-activating protein kinase kinase kinase kinase-3 (MAP4K3). Those molecular links between mTORC1 and its mediators form a complicate signaling network that controls cellular growth, proliferation, and metabolism. Moreover, it is speculated that amino acid signaling to mTORC1 may start from the lysosomal lumen. In this review, we discussed the function of these mediators in mTORC1 pathway and how these mediators are regulated by amino acids in details.

  17. Akt inhibition promotes ABCA1-mediated cholesterol efflux to ApoA-I through suppressing mTORC1.

    Directory of Open Access Journals (Sweden)

    Fumin Dong

    Full Text Available ATP-binding cassette transporter A1 (ABCA1 plays an essential role in mediating cholesterol efflux to apolipoprotein A-I (apoA-I, a major housekeeping mechanism for cellular cholesterol homeostasis. After initial engagement with ABCA1, apoA-I directly interacts with the plasma membrane to acquire cholesterol. This apoA-I lipidation process is also known to require cellular signaling processes, presumably to support cholesterol trafficking to the plasma membrane. We report here that one of major signaling pathways in mammalian cells, Akt, is also involved. In several cell models that express ABCA1 including macrophages, pancreatic beta cells and hepatocytes, inhibition of Akt increases cholesterol efflux to apoA-I. Importantly, Akt inhibition has little effect on cells expressing non-functional mutant of ABCA1, implicating a specific role of Akt in ABCA1 function. Furthermore, we provide evidence that mTORC1, a major downstream target of Akt, is also a negative regulator of cholesterol efflux. In cells where mTORC1 is constitutively activated due to tuberous sclerosis complex 2 deletion, cholesterol efflux to apoA-I is no longer sensitive to Akt activity. This suggests that Akt suppresses cholesterol efflux through mTORC1 activation. Indeed, inhibition of mTORC1 by rapamycin or Torin-1 promotes cholesterol efflux. On the other hand, autophagy, one of the major pathways of cholesterol trafficking, is increased upon Akt inhibition. Furthermore, Akt inhibition disrupts lipid rafts, which is known to promote cholesterol efflux to apoA-I. We therefore conclude that Akt, through its downstream targets, mTORC1 and hence autophagy, negatively regulates cholesterol efflux to apoA-I.

  18. Ketamine accelerates fear extinction via mTORC1 signaling.

    Science.gov (United States)

    Girgenti, Matthew J; Ghosal, Sriparna; LoPresto, Dora; Taylor, Jane R; Duman, Ronald S

    2017-04-01

    Impaired fear extinction contributes to the persistence of post-traumatic stress disorder (PTSD), and can be utilized for the study of novel therapeutic agents. Glutamate plays an important role in the formation of traumatic memories, and in the pathophysiology and treatment of PTSD, highlighting several possible drug targets. Recent clinical studies demonstrate that infusion of ketamine, a glutamate NMDA receptor antagonist, rapidly and significantly reduces symptom severity in PTSD patients. In the present study, we examine the mechanisms underlying the actions of ketamine in a rodent model of fear conditioning, extinction, and renewal. Rats received ketamine or saline 24h after fear conditioning and were then subjected to extinction-training on each of the following three days. Ketamine administration enhanced extinction on the second day of training (i.e., reduced freezing behavior to cue) and produced a long-lasting reduction in freezing on exposure to cue plus context 8days later. Additionally, ketamine and extinction exposure increased levels of mTORC1 in the medial prefrontal cortex (mPFC), a region involved in the acquisition and retrieval of extinction, and infusion of the selective mTORC1 inhibitor rapamycin into the mPFC blocked the effects of ketamine on extinction. Ketamine plus extinction also increased cFos in the mPFC and administration of a glutamate-AMPA receptor antagonist blocked the effects of ketamine. These results support the hypothesis that ketamine produces long-lasting mTORC1/protein synthesis and activity dependent effects on neuronal circuits that enhance the expression of extinction and could represent a novel approach for the treatment of PTSD. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. mTORC1 is a critical mediator of oncogenic Semaphorin3A signaling

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Daisuke; Kawahara, Kohichi; Maeda, Takehiko, E-mail: maeda@nupals.ac.jp

    2016-08-05

    Aberration of signaling pathways by genetic mutations or alterations in the surrounding tissue environments can result in tumor development or metastasis. However, signaling molecules responsible for these processes have not been completely elucidated. Here, we used mouse Lewis lung carcinoma cells (LLC) to explore the mechanism by which the oncogenic activity of Semaphorin3A (Sema3A) signaling is regulated. Sema3A knockdown by shRNA did not affect apoptosis, but decreased cell proliferation in LLCs; both the mammalian target of rapamycin complex 1 (mTORC1) level and glycolytic activity were also decreased. In addition, Sema3A knockdown sensitized cells to inhibition of oxidative phosphorylation by oligomycin, but conferred resistance to decreased cell viability induced by glucose starvation. Furthermore, recombinant SEMA3A rescued the attenuation of cell proliferation and glycolytic activity in LLCs after Sema3A knockdown, whereas mTORC1 inhibition by rapamycin completely counteracted this effect. These results demonstrate that Sema3A signaling exerts its oncogenic effect by promoting an mTORC1-mediated metabolic shift from oxidative phosphorylation to aerobic glycolysis. -- Highlights: •Sema3A knockdown decreased proliferation of Lewis lung carcinoma cells (LLCs). •Sema3A knockdown decreased mTORC1 levels and glycolytic activity in LLCs. •Sema3A knockdown sensitized cells to inhibition of oxidative phosphorylation. •Sema3A promotes shift from oxidative phosphorylation to aerobic glycolysis via mTORC1.

  20. Growth factor signaling to mTORC1 by amino acid–laden macropinosomes

    Science.gov (United States)

    Yoshida, Sei; Pacitto, Regina; Yao, Yao; Inoki, Ken

    2015-01-01

    The rapid activation of the mechanistic target of rapamycin complex-1 (mTORC1) by growth factors is increased by extracellular amino acids through yet-undefined mechanisms of amino acid transfer into endolysosomes. Because the endocytic process of macropinocytosis concentrates extracellular solutes into endolysosomes and is increased in cells stimulated by growth factors or tumor-promoting phorbol esters, we analyzed its role in amino acid–dependent activation of mTORC1. Here, we show that growth factor-dependent activation of mTORC1 by amino acids, but not glucose, requires macropinocytosis. In murine bone marrow–derived macrophages and murine embryonic fibroblasts stimulated with their cognate growth factors or with phorbol myristate acetate, activation of mTORC1 required an Akt-independent vesicular pathway of amino acid delivery into endolysosomes, mediated by the actin cytoskeleton. Macropinocytosis delivered small, fluorescent fluid-phase solutes into endolysosomes sufficiently fast to explain growth factor–mediated signaling by amino acids. Therefore, the amino acid–laden macropinosome is an essential and discrete unit of growth factor receptor signaling to mTORC1. PMID:26438830

  1. Recovery of strength is dependent on mTORC1 signaling after eccentric muscle injury.

    Science.gov (United States)

    Baumann, Cory Walter; Rogers, Russell George; Otis, Jeffrey Scott; Ingalls, Christopher Paul

    2016-11-01

    Eccentric contractions may cause immediate and long-term reductions in muscle strength that can be recovered through increased protein synthesis rates. The purpose of this study was to determine whether the mechanistic target-of-rapamycin complex 1 (mTORC1), a vital controller of protein synthesis rates, is required for return of muscle strength after injury. Isometric muscle strength was assessed before, immediately after, and then 3, 7, and 14 days after a single bout of 150 eccentric contractions in mice that received daily injections of saline or rapamycin. The bout of eccentric contractions increased the phosphorylation of mTORC1 (1.8-fold) and p70s6k1 (13.8-fold), mTORC1's downstream effector, 3 days post-injury. Rapamycin blocked mTORC1 and p70s6k1 phosphorylation and attenuated recovery of muscle strength (∼20%) at 7 and 14 days. mTORC1 signaling is instrumental in the return of muscle strength after a single bout of eccentric contractions in mice. Muscle Nerve 54: 914-924, 2016. © 2016 Wiley Periodicals, Inc.

  2. mTORC1 signalling mediates PI3K-dependent large lipid droplet accumulation in Drosophila ovarian nurse cells

    Directory of Open Access Journals (Sweden)

    Lawrence B. Mensah

    2017-05-01

    Full Text Available Insulin and insulin-like growth factor signalling (IIS, which is primarily mediated by the PI3-kinase (PI3K/PTEN/Akt kinase signalling cassette, is a highly evolutionarily conserved pathway involved in co-ordinating growth, development, ageing and nutrient homeostasis with dietary intake. It controls transcriptional regulators, in addition to promoting signalling by mechanistic target of rapamycin (mTOR complex 1 (mTORC1, which stimulates biosynthesis of proteins and other macromolecules, and drives organismal growth. Previous studies in nutrient-storing germline nurse cells of the Drosophila ovary showed that a cytoplasmic pool of activated phosphorylated Akt (pAkt controlled by Pten, an antagonist of IIS, cell-autonomously regulates accumulation of large lipid droplets in these cells at late stages of oogenesis. Here, we show that the large lipid droplet phenotype induced by Pten mutation is strongly suppressed when mTor function is removed. Furthermore, nurse cells lacking either Tsc1 or Tsc2, which negatively regulate mTORC1 activity, also accumulate large lipid droplets via a mechanism involving Rheb, the downstream G-protein target of TSC2, which positively regulates mTORC1. We conclude that elevated IIS/mTORC1 signalling is both necessary and sufficient to induce large lipid droplet formation in late-stage nurse cells, suggesting roles for this pathway in aspects of lipid droplet biogenesis, in addition to control of lipid metabolism.

  3. Livers with constitutive mTORC1 activity resist steatosis independent of feedback suppression of Akt.

    Directory of Open Access Journals (Sweden)

    Heidi L Kenerson

    Full Text Available Insulin resistance is an important contributing factor in non-alcoholic fatty liver disease. AKT and mTORC1 are key components of the insulin pathway, and play a role in promoting de novo lipogenesis. However, mTORC1 hyperactivity per se does not induce steatosis in mouse livers, but instead, protects against high-fat diet induced steatosis. Here, we investigate the in vivo mechanism of steatosis-resistance secondary to mTORC1 activation, with emphasis on the role of S6K1-mediated feedback inhibition of AKT. Mice with single or double deletion of Tsc1 and/or S6k1 in a liver-specific or whole-body manner were generated to study glucose and hepatic lipid metabolism between the ages of 6-14 weeks. Following 8 weeks of high-fat diet, the Tsc1-/-;S6k1-/- mice had lower body weights but higher liver TG levels compared to that of the Tsc1-/- mice. However, the loss of S6k1 did not relieve feedback inhibition of Akt activity in the Tsc1-/- livers. To overcome Akt suppression, Pten was deleted in Tsc1-/- livers, and the resultant mice showed improved glucose tolerance compared with the Tsc1-/- mice. However, liver TG levels were significantly reduced in the Tsc1-/-;Pten-/- mice compared to the Pten-/- mice, which was restored with rapamycin. We found no correlation between liver TG and serum NEFA levels. Expression of lipogenic genes (Srebp1c, Fasn were elevated in the Tsc1-/-;Pten-/- livers, but this was counter-balanced by an up-regulation of Cpt1a involved in fatty acid oxidation and the anti-oxidant protein, Nrf2. In summary, our in vivo models showed that mTORC1-induced resistance to steatosis was dependent on S6K1 activity, but not secondary to AKT suppression. These findings confirm that AKT and mTORC1 have opposing effects on hepatic lipid metabolism in vivo.

  4. Crosstalk between mTORC1 and cAMP Signaling

    Science.gov (United States)

    2016-09-01

    target of rapamycin (mTOR) complex 1 (mTORC1) integrates environmental and intracellular signals to regulate cell growth. Aminoacids ...J, Matsumoto K. 2003a. The TAK1–NLK mitogen-activated protein kinase cascade functions in the Wnt-5a/Ca2+ pathway to antagonize Wnt/β-catenin

  5. Amino Acids Attenuate Insulin Action on Gluconeogenesis and Promote Fatty Acid Biosynthesis via mTORC1 Signaling Pathway in trout Hepatocytes

    Directory of Open Access Journals (Sweden)

    Weiwei Dai

    2015-06-01

    Full Text Available Background/Aims: Carnivores exhibit poor utilization of dietary carbohydrates and glucose intolerant phenotypes, yet it remains unclear what are the causal factors and underlying mechanisms. We aimed to evaluate excessive amino acids (AAs-induced effects on insulin signaling, fatty acid biosynthesis and glucose metabolism in rainbow trout and determine the potential involvement of mTORC1 and p38 MAPK pathway. Methods: We stimulated trout primary hepatocytes with different AA levels and employed acute administration of rapamycin to inhibit mTORC1 activation. Results: Increased AA levels enhanced the phosphorylation of ribosomal protein S6 kinase (S6K1, S6, and insulin receptor substrate 1 (IRS-1 on Ser302 but suppressed Akt and p38 phosphorylation; up-regulated the expression of genes related to gluconeogenesis and fatty acid biosynthesis. mTORC1 inhibition not only inhibited the phosphorylation of mTORC1 downstream targets, but also blunted IRS-1 Ser302 phosphorylation and restored excessive AAs-suppressed Akt phosphorylation. Rapamycin also inhibited fatty acid biosynthetic and gluconeogenic gene expression. Conclusion: High levels of AAs up-regulate hepatic fatty acid biosynthetic gene expression through an mTORC1-dependent manner, while attenuate insulin-mediated repression of gluconeogenesis through elevating IRS-1 Ser302 phosphorylation, which in turn impairs Akt activation and thereby weakening insulin action. We propose that p38 MAPK probably also involves in these AAs-induced metabolic changes.

  6. CDX2 Stimulates the Proliferation of Porcine Intestinal Epithelial Cells by Activating the mTORC1 and Wnt/β-Catenin Signaling Pathways.

    Science.gov (United States)

    Fan, Hong-Bo; Zhai, Zhen-Ya; Li, Xiang-Guang; Gao, Chun-Qi; Yan, Hui-Chao; Chen, Zhe-Sheng; Wang, Xiu-Qi

    2017-11-18

    Caudal type homeobox 2 (CDX2) is expressed in intestinal epithelial cells and plays a role in gut development and homeostasis by regulating cell proliferation. However, whether CDX2 cooperates with the mammalian target of rapamycin complex 1 (mTORC1) and Wnt/β-catenin signaling pathways to stimulate cell proliferation remains unknown. The objective of this study was to investigate the effect of CDX2 on the proliferation of porcine jejunum epithelial cells (IPEC-J2) and the correlation between CDX2, the mTORC1 and Wnt/β-catenin signaling pathways. CDX2 overexpression and knockdown cell culture models were established to explore the regulation of CDX2 on both pathways. Pathway-specific antagonists were used to verify the effects. The results showed that CDX2 overexpression increased IPEC-J2 cell proliferation and activated both the mTORC1 and Wnt/β-catenin pathways, and that CDX2 knockdown decreased cell proliferation and inhibited both pathways. Furthermore, the mTORC1 and Wnt/β-catenin pathway-specific antagonist rapamycin and XAV939 (3,5,7,8-tetrahydro-2-[4-(trifluoromethyl)]-4H -thiopyrano[4,3-d]pyrimidin-4-one) both suppressed the proliferation of IPEC-J2 cells overexpressing CDX2, and that the combination of rapamycin and XAV939 had an additive effect. Regardless of whether the cells were treated with rapamycin or XAV939 alone or in combination, both mTORC1 and Wnt/β-catenin pathways were down-regulated, accompanied by a decrease in CDX2 expression. Taken together, our data indicate that CDX2 stimulates porcine intestinal epithelial cell proliferation by activating the mTORC1 and Wnt/β-catenin signaling pathways.

  7. CGEF-1 regulates mTORC1 signaling during adult longevity and stress response inC. elegans.

    Science.gov (United States)

    Li, Yujie; Finkbeiner, Sandra; Ganner, Athina; Gerber, Julia; Klein, Marinella; Grafe, Manuel; Kandzia, Jakob; Thien, Antje; Thedieck, Kathrin; Breves, Gerhard; Jank, Thomas; Baumeister, Ralf; Walz, Gerd; Neumann-Haefelin, Elke

    2018-02-09

    The mechanistic target of rapamycin (mTOR) kinase is central to metabolism and growth, and has a conserved role in aging. mTOR functions in two complexes, mTORC1 and mTORC2. In diverse eukaryotes, inhibition of mTORC1 signaling increases lifespan. mTORC1 transduces anabolic signals to stimulate protein synthesis and inhibits autophagy. In this study, we demonstrate that CGEF-1, the C. elegans homolog of the human guanine nucleotide exchange factor Dbl, is a novel binding partner of RHEB-1 and activator of mTORC1 signaling in C. elegans . cgef-1 mutants display prolonged lifespan and enhanced stress resistance. The transcription factors DAF-16/FoxO and SKN-1/Nrf are required for increased longevity and stress tolerance, and induce protective gene expression in cgef-1 mutants. Genetic evidence indicates that cgef-1 functions in the same pathway with rheb-1 , the mTOR kinase let-363 , and daf-15 /Raptor. When cgef-1 is inactivated, phosphorylation of 4E-BP, a central mTORC1 substrate for protein translation is reduced in C. elegans . Moreover, autophagy is increased upon cgef-1 and mTORC1 inhibition. In addition, we show that in human cells Dbl associates with Rheb and stimulates mTORC1 downstream targets for protein synthesis suggesting that the function of CGEF-1/Dbl in the mTORC1 signaling pathway is evolutionarily conserved. These findings have important implications for mTOR functions and signaling mechanisms in aging and age-related diseases.

  8. Dual mTORC1/C2 inhibitors suppress cellular geroconversion (a senescence program).

    Science.gov (United States)

    Leontieva, Olga V; Demidenko, Zoya N; Blagosklonny, Mikhail V

    2015-09-15

    In proliferating cells, mTOR is active and promotes cell growth. When the cell cycle is arrested, then mTOR converts reversible arrest to senescence (geroconversion). Rapamycin and other rapalogs suppress geroconversion, maintaining quiescence instead. Here we showed that ATP-competitive kinase inhibitors (Torin1 and PP242), which inhibit both mTORC1 and TORC2, also suppressed geroconversion. Despite inhibition of proliferation (in proliferating cells), mTOR inhibitors preserved re-proliferative potential (RP) in arrested cells. In p21-arrested cells, Torin 1 and PP242 detectably suppressed geroconversion at concentrations as low as 1-3 nM and 10-30 nM, reaching maximal gerosuppression at 30 nM and 300 nM, respectively. Near-maximal gerosuppression coincided with inhibition of p-S6K(T389) and p-S6(S235/236). Dual mTOR inhibitors prevented senescent morphology and hypertrophy. Our study warrants investigation into whether low doses of dual mTOR inhibitors will prolong animal life span and delay age-related diseases. A new class of potential anti-aging drugs can be envisioned.

  9. TGFβ-induced deptor suppression recruits mTORC1 and not mTORC2 to enhance collagen I (α2 gene expression.

    Directory of Open Access Journals (Sweden)

    Falguni Das

    Full Text Available Enhanced TGFβ activity contributes to the accumulation of matrix proteins including collagen I (α2 by proximal tubular epithelial cells in progressive kidney disease. Although TGFβ rapidly activates its canonical Smad signaling pathway, it also recruits noncanonical pathway involving mTOR kinase to regulate renal matrix expansion. The mechanism by which chronic TGFβ treatment maintains increased mTOR activity to induce the matrix protein collagen I (α2 expression is not known. Deptor is an mTOR interacting protein that suppresses mTOR activity in both mTORC1 and mTORC2. In proximal tubular epithelial cells, TGFβ reduced deptor levels in a time-dependent manner with concomitant increase in both mTORC1 and mTORC2 activities. Expression of deptor abrogated activity of mTORC1 and mTORC2, resulting in inhibition of collagen I (α2 mRNA and protein expression via transcriptional mechanism. In contrast, neutralization of endogenous deptor by shRNAs increased activity of both mTOR complexes and expression of collagen I (α2 similar to TGFβ treatment. Importantly, downregulation of deptor by TGFβ increased the expression of Hif1α by increasing translation of its mRNA. TGFβ-induced deptor downregulation promotes Hif1α binding to its cognate hypoxia responsive element in the collagen I (α2 gene to control its protein expression via direct transcriptional mechanism. Interestingly, knockdown of raptor to specifically block mTORC1 activity significantly inhibited expression of collagen I (α2 and Hif1α while inhibition of rictor to prevent selectively mTORC2 activation did not have any effect. Critically, our data provide evidence for the requirement of TGFβ-activated mTORC1 only by deptor downregulation, which dominates upon the bystander mTORC2 activity for enhanced expression of collagen I (α2. Our results also suggest the presence of a safeguard mechanism involving deptor-mediated suppression of mTORC1 activity against developing TGF

  10. Astragaloside IV Ameliorates Airway Inflammation in an Established Murine Model of Asthma by Inhibiting the mTORC1 Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Hualiang Jin

    2017-01-01

    Full Text Available Astragaloside IV (AS-IV, a main active constituent of Astragalus membranaceus, has been confirmed to have antiasthmatic effects. However, it remained unclear whether the beneficial effects of AS-IV on asthma were attributed to the mTOR inhibition; this issue was the focus of the present work. BALB/c mice were sensitized and challenged with ovalbumin followed with 3 weeks of rest/recovery and then reexposure to ovalbumin. AS-IV was administrated during the time of rest and reexposure. The characteristic features of allergic asthma, including airway hyperreactivity, histopathology, cytokines (IL-4, IL-5, IL-13, IL-17, and INF-γ, and CD4+CD25+Foxp3+Treg cells in bronchoalveolar lavage fluid (BALF, and downstream proteins of mTORC1/2 signaling were examined. AS-IV markedly suppressed airway hyperresponsiveness and reduced IL-4, IL-5, and IL-17 levels and increased INF-γ levels in the BALF. Histological studies showed that AS-IV markedly decreased inflammatory infiltration in the lung tissues. Notably, AS-IV inhibited mTORC1 activity, whereas it had limited effects on mTORC2, as assessed by phosphorylation of mTORC1 and mTORC2 substrates S6 ribosomal protein, p70 S6 Kinase, and Akt, respectively. CD4+CD25+Foxp3+Treg cells in BALF were not significantly changed by AS-IV. Together, these results suggest that the antiasthmatic effects of AS-IV were at least partially from inhibiting the mTORC1 signaling pathway.

  11. 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.

  12. Opposing regulation of the late phase TNF response by mTORC1-IL-10 signaling and hypoxia in human macrophages

    Science.gov (United States)

    Huynh, Linda; Kusnadi, Anthony; Park, Sung Ho; Murata, Koichi; Park-Min, Kyung-Hyun; Ivashkiv, Lionel B.

    2016-01-01

    Tumor necrosis factor (TNF) is best known for inducing a rapid but transient NF-κB-mediated inflammatory response. We investigated later phases of TNF signaling, after the initial transient induction of inflammatory genes has subsided, in primary human macrophages. TNF signaling induced expression of late response genes, including inhibitors of NF-κB and TLR signaling, with delayed and sustained kinetics 6–24 hr after TNF stimulation. A subset of late phase genes was expressed in rheumatoid arthritis synovial macrophages, confirming their expression under chronic inflammatory conditions in vivo. Expression of a subset of late phase genes was mediated by autocrine IL-10, which activated STAT3 with delayed kinetics. Hypoxia, which occurs at sites of infection or inflammation where TNF is expressed, suppressed this IL-10-STAT3 autocrine loop and expression of late phase genes. TNF-induced expression of IL-10 and downstream genes was also dependent on signaling by mTORC1, which senses the metabolic state of cells and is modulated by hypoxia. These results reveal an mTORC1-dependent IL-10-mediated late phase response to TNF by primary human macrophages, and identify suppression of IL-10 responses as a new mechanism by which hypoxia can promote inflammation. Thus, hypoxic and metabolic pathways may modulate TNF responses during chronic inflammation. PMID:27558590

  13. Methionine Induces LAT1 Expression in Dairy Cow Mammary Gland by Activating the mTORC1 Signaling Pathway.

    Science.gov (United States)

    Duan, Xiaoyu; Lin, Ye; Lv, He; Yang, Yang; Jiao, Hongtao; Hou, Xiaoming

    2017-12-01

    Methionine is the limiting amino acid for milk protein synthesis in dairy cows. The effect of methionine availability on milk protein synthesis is dependent on its active transport into cells through amino acid transporters. L-type amino acid transporter 1 (LAT1), which induces the transport of neutral amino acids, is highly expressed in lactating mammary gland. However, the effect of methionine on LAT1 expression and the mechanism governing this process in dairy cow mammary gland are poorly understood. In this study, we show that treatment of dairy cow mammary epithelial cells with increasing concentrations of methionine for 24 h resulted in increased expression of LAT1 and its associated protein 4F2 heavy chain (4F2hc). Maximal expression levels occurred after treatment with 0.6 mM methionine. Methionine treatment also increased cell viability and β-casein synthesis. Western blots showed that methionine induced LAT1 and 4F2hc expression by activating mammalian target of rapamycin complex 1 (mTORC1) signaling. Inhibition of mTORC1 signaling by rapamycin or raptor siRNA prevented the upregulation of LAT1 and 4F2hc. These results indicate that methionine may activate the mTORC1 signaling pathway and further increase LAT1 and 4F2hc expression in dairy cow mammary gland, thus affecting milk protein synthesis.

  14. Selective Activation of mTORC1 Signaling Recapitulates Microcephaly, Tuberous Sclerosis, and Neurodegenerative Diseases

    Directory of Open Access Journals (Sweden)

    Hidetoshi Kassai

    2014-06-01

    Full Text Available Mammalian target of rapamycin (mTOR has been implicated in human neurological diseases such as tuberous sclerosis complex (TSC, neurodegeneration, and autism. However, little is known about when and how mTOR is involved in the pathogenesis of these diseases, due to a lack of animal models that directly increase mTOR activity. Here, we generated transgenic mice expressing a gain-of-function mutant of mTOR in the forebrain in a temporally controlled manner. Selective activation of mTORC1 in embryonic stages induced cortical atrophy caused by prominent apoptosis of neuronal progenitors, associated with upregulation of HIF-1α. In striking contrast, activation of the mTORC1 pathway in adulthood resulted in cortical hypertrophy with fatal epileptic seizures, recapitulating human TSC. Activated mTORC1 in the adult cortex also promoted rapid accumulation of cytoplasmic inclusions and activation of microglial cells, indicative of progressive neurodegeneration. Our findings demonstrate that mTORC1 plays different roles in developmental and adult stages and contributes to human neurological diseases.

  15. C. elegans DAF-16/FOXO interacts with TGF-ß/BMP signaling to induce germline tumor formation via mTORC1 activation.

    Science.gov (United States)

    Qi, Wenjing; Yan, Yijian; Pfeifer, Dietmar; Donner V Gromoff, Erika; Wang, Yimin; Maier, Wolfgang; Baumeister, Ralf

    2017-05-01

    Activation of the FOXO transcription factor DAF-16 by reduced insulin/IGF signaling (IIS) is considered to be beneficial in C. elegans due to its ability to extend lifespan and to enhance stress resistance. In the germline, cell-autonomous DAF-16 activity prevents stem cell proliferation, thus acting tumor-suppressive. In contrast, hypodermal DAF-16 causes a tumorous germline phenotype characterized by hyperproliferation of the germline stem cells and rupture of the adjacent basement membrane. Here we show that cross-talk between DAF-16 and the transforming growth factor ß (TGFß)/bone morphogenic protein (BMP) signaling pathway causes germline hyperplasia and results in disruption of the basement membrane. In addition to activating MADM/NRBP/hpo-11 gene alone, DAF-16 also directly interacts with both R-SMAD proteins SMA-2 and SMA-3 in the nucleus to regulate the expression of mTORC1 pathway. Knocking-down of BMP genes or each of the four target genes in the hypodermis was sufficient to inhibit germline proliferation, indicating a cell-non-autonomously controlled regulation of stem cell proliferation by somatic tissues. We propose the existence of two antagonistic DAF-16/FOXO functions, a cell-proliferative somatic and an anti-proliferative germline activity. Whereas germline hyperplasia under reduced IIS is inhibited by DAF-16 cell-autonomously, activation of somatic DAF-16 in the presence of active IIS promotes germline proliferation and eventually induces tumor-like germline growth. In summary, our results suggest a novel pathway crosstalk of DAF-16 and TGF-ß/BMP that can modulate mTORC1 at the transcriptional level to cause stem-cell hyperproliferation. Such cell-type specific differences may help explaining why human FOXO activity is considered to be tumor-suppressive in most contexts, but may become oncogenic, e.g. in chronic and acute myeloid leukemia.

  16. C. elegans DAF-16/FOXO interacts with TGF-ß/BMP signaling to induce germline tumor formation via mTORC1 activation.

    Directory of Open Access Journals (Sweden)

    Wenjing Qi

    2017-05-01

    Full Text Available Activation of the FOXO transcription factor DAF-16 by reduced insulin/IGF signaling (IIS is considered to be beneficial in C. elegans due to its ability to extend lifespan and to enhance stress resistance. In the germline, cell-autonomous DAF-16 activity prevents stem cell proliferation, thus acting tumor-suppressive. In contrast, hypodermal DAF-16 causes a tumorous germline phenotype characterized by hyperproliferation of the germline stem cells and rupture of the adjacent basement membrane. Here we show that cross-talk between DAF-16 and the transforming growth factor ß (TGFß/bone morphogenic protein (BMP signaling pathway causes germline hyperplasia and results in disruption of the basement membrane. In addition to activating MADM/NRBP/hpo-11 gene alone, DAF-16 also directly interacts with both R-SMAD proteins SMA-2 and SMA-3 in the nucleus to regulate the expression of mTORC1 pathway. Knocking-down of BMP genes or each of the four target genes in the hypodermis was sufficient to inhibit germline proliferation, indicating a cell-non-autonomously controlled regulation of stem cell proliferation by somatic tissues. We propose the existence of two antagonistic DAF-16/FOXO functions, a cell-proliferative somatic and an anti-proliferative germline activity. Whereas germline hyperplasia under reduced IIS is inhibited by DAF-16 cell-autonomously, activation of somatic DAF-16 in the presence of active IIS promotes germline proliferation and eventually induces tumor-like germline growth. In summary, our results suggest a novel pathway crosstalk of DAF-16 and TGF-ß/BMP that can modulate mTORC1 at the transcriptional level to cause stem-cell hyperproliferation. Such cell-type specific differences may help explaining why human FOXO activity is considered to be tumor-suppressive in most contexts, but may become oncogenic, e.g. in chronic and acute myeloid leukemia.

  17. Constitutive activation of CaMKKα signaling is sufficient but not necessary for mTORC1 activation and growth in mouse skeletal muscle

    Science.gov (United States)

    Ferey, Jeremie L. A.; Brault, Jeffrey J.; Smith, Cheryl A. S.

    2014-01-01

    Skeletal muscle loading/overload stimulates the Ca2+-activated, serine/threonine kinase Ca2+/calmodulin-dependent protein kinase kinase-α (CaMKKα); yet to date, no studies have examined whether CaMKKα regulates muscle growth. The purpose of this study was to determine if constitutive activation of CaMKKα signaling could stimulate muscle growth and if so whether CaMKKα is essential for this process. CaMKKα signaling was selectively activated in mouse muscle via expression of a constitutively active form of CaMKKα using in vivo electroporation. After 2 wk, constitutively active CaMKKα expression increased muscle weight (∼10%) and protein content (∼10%), demonstrating that activation of CaMKKα signaling can stimulate muscle growth. To determine if active CaMKKα expression stimulated muscle growth via increased mammalian target of rapamycin complex 1 (mTORC1) signaling and protein synthesis, [3H]phenylalanine incorporation into proteins was assessed with or without the mTORC1 inhibitor rapamycin. Constitutively active CaMKKα increased protein synthesis ∼60%, and this increase was prevented by rapamycin, demonstrating a critical role for mTORC1 in this process. To determine if CaMKKα is essential for growth, muscles from CaMKKα knockout mice were stimulated to hypertrophy via unilateral ablation of synergist muscles (overload). Surprisingly, compared with wild-type mice, muscles from CaMKKα knockout mice exhibited greater growth (∼15%) and phosphorylation of the mTORC1 substrate 70-kDa ribosomal protein S6 kinase (Thr389; ∼50%), demonstrating that CaMKKα is not essential for overload-induced mTORC1 activation or muscle growth. Collectively, these results demonstrate that activation of CaMKKα signaling is sufficient but not necessary for activation of mTORC1 signaling and growth in mouse skeletal muscle. PMID:25159322

  18. Milk is not just food but most likely a genetic transfection system activating mTORC1 signaling for postnatal growth.

    Science.gov (United States)

    Melnik, Bodo C; John, Swen Malte; Schmitz, Gerd

    2013-07-25

    Milk has been recognized to represent a functionally active nutrient system promoting neonatal growth of mammals. Cell growth is regulated by the nutrient-sensitive kinase mechanistic target of rapamycin complex 1 (mTORC1). There is still a lack of information on the mechanisms of mTORC1 up-regulation by milk consumption. This review presents milk as a materno-neonatal relay system functioning by transfer of preferential amino acids, which increase plasma levels of glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1), insulin, growth hormone (GH) and insulin-like growth factor-1 (IGF-1) for mTORC1 activation. Importantly, milk exosomes, which regularly contain microRNA-21, most likely represent a genetic transfection system enhancing mTORC1-driven metabolic processes. Whereas human breast milk is the ideal food for infants allowing appropriate postnatal growth and species-specific metabolic programming, persistent high milk signaling during adolescence and adulthood by continued cow´s milk consumption may promote mTORC1-driven diseases of civilization.

  19. mTORC1 controls fasting-induced ketogenesis and its modulation by ageing.

    Science.gov (United States)

    Sengupta, Shomit; Peterson, Timothy R; Laplante, Mathieu; Oh, Stephanie; Sabatini, David M

    2010-12-23

    The multi-component mechanistic target of rapamycin complex 1 (mTORC1) kinase is the central node of a mammalian pathway that coordinates cell growth with the availability of nutrients, energy and growth factors. Progress has been made in the identification of mTORC1 pathway components and in understanding their functions in cells, but there is relatively little known about the role of the pathway in vivo. Specifically, we have little knowledge regarding the role mTOCR1 has in liver physiology. In fasted animals, the liver performs numerous functions that maintain whole-body homeostasis, including the production of ketone bodies for peripheral tissues to use as energy sources. Here we show that mTORC1 controls ketogenesis in mice in response to fasting. We find that liver-specific loss of TSC1 (tuberous sclerosis 1), an mTORC1 inhibitor, leads to a fasting-resistant increase in liver size, and to a pronounced defect in ketone body production and ketogenic gene expression on fasting. The loss of raptor (regulatory associated protein of mTOR, complex 1) an essential mTORC1 component, has the opposite effects. In addition, we find that the inhibition of mTORC1 is required for the fasting-induced activation of PPARα (peroxisome proliferator activated receptor α), the master transcriptional activator of ketogenic genes, and that suppression of NCoR1 (nuclear receptor co-repressor 1), a co-repressor of PPARα, reactivates ketogenesis in cells and livers with hyperactive mTORC1 signalling. Like livers with activated mTORC1, livers from aged mice have a defect in ketogenesis, which correlates with an increase in mTORC1 signalling. Moreover, we show that the suppressive effects of mTORC1 activation and ageing on PPARα activity and ketone production are not additive, and that mTORC1 inhibition is sufficient to prevent the ageing-induced defect in ketogenesis. Thus, our findings reveal that mTORC1 is a key regulator of PPARα function and hepatic ketogenesis and suggest a

  20. Striatal Transcriptome and Interactome Analysis of Shank3-overexpressing Mice Reveals the Connectivity between Shank3 and mTORC1 Signaling

    Directory of Open Access Journals (Sweden)

    Yeunkum Lee

    2017-06-01

    Full Text Available Mania causes symptoms of hyperactivity, impulsivity, elevated mood, reduced anxiety and decreased need for sleep, which suggests that the dysfunction of the striatum, a critical component of the brain motor and reward system, can be causally associated with mania. However, detailed molecular pathophysiology underlying the striatal dysfunction in mania remains largely unknown. In this study, we aimed to identify the molecular pathways showing alterations in the striatum of SH3 and multiple ankyrin repeat domains 3 (Shank3-overexpressing transgenic (TG mice that display manic-like behaviors. The results of transcriptome analysis suggested that mammalian target of rapamycin complex 1 (mTORC1 signaling may be the primary molecular signature altered in the Shank3 TG striatum. Indeed, we found that striatal mTORC1 activity, as measured by mTOR S2448 phosphorylation, was significantly decreased in the Shank3 TG mice compared to wild-type (WT mice. To elucidate the potential underlying mechanism, we re-analyzed previously reported protein interactomes, and detected a high connectivity between Shank3 and several upstream regulators of mTORC1, such as tuberous sclerosis 1 (TSC1, TSC2 and Ras homolog enriched in striatum (Rhes, via 94 common interactors that we denominated “Shank3-mTORC1 interactome”. We noticed that, among the 94 common interactors, 11 proteins were related to actin filaments, the level of which was increased in the dorsal striatum of Shank3 TG mice. Furthermore, we could co-immunoprecipitate Shank3, Rhes and Wiskott-Aldrich syndrome protein family verprolin-homologous protein 1 (WAVE1 proteins from the striatal lysate of Shank3 TG mice. By comparing with the gene sets of psychiatric disorders, we also observed that the 94 proteins of Shank3-mTORC1 interactome were significantly associated with bipolar disorder (BD. Altogether, our results suggest a protein interaction-mediated connectivity between Shank3 and certain upstream

  1. The pathogenic role of persistent milk signaling in mTORC1- and milk-microRNA-driven type 2 diabetes mellitus.

    Science.gov (United States)

    Melnik, Bodo C

    2015-01-01

    Milk, the secretory product of the lactation genome, promotes growth of the newborn mammal. Milk delivers insulinotropic amino acids, thus maintains a molecular crosstalk with the pancreatic β-cell of the milk recipient. Homeostasis of β-cells and insulin production depend on the appropriate magnitude of mTORC1 signaling. mTORC1 is activated by branched-chain amino acids (BCAAs), glutamine, and palmitic acid, abundant nutrient signals of cow´s milk. Furthermore, milk delivers bioactive exosomal microRNAs. After milk consumption, bovine microRNA-29b, a member of the diabetogenic microRNA-29- family, reaches the systemic circulation and the cells of the milk consumer. MicroRNA-29b downregulates branchedchain α-ketoacid dehydrogenase, a potential explanation for increased BCAA serum levels, the metabolic signature of insulin resistance and type 2 diabetes mellitus (T2DM). In non-obese diabetic mice, microRNA-29b downregulates the antiapoptotic protein Mcl-1, which leads to early β-cell death. In all mammals except Neolithic humans, milk-driven mTORC1 signaling is physiologically restricted to the postnatal period. In contrast, chronic hyperactivated mTORC1 signaling has been associated with the development of age-related diseases of civilization including T2DM. Notably, chronic hyperactivation of mTORC1 enhances endoplasmic reticulum stress that promotes apoptosis. In fact, hyperactivated β-cell mTORC1 signaling induced early β-cell apoptosis in a mouse model. The EPIC-InterAct Study demonstrated an association between milk consumption and T2DM in France, Italy, United Kingdom, Germany, and Sweden. In contrast, fermented milk products and cheese exhibit an inverse correlation. Since the early 1950´s, refrigeration technology allowed widespread consumption of fresh pasteurized milk, which facilitates daily intake of bioactive bovine microRNAs. Persistent uptake of cow´s milk-derived microRNAs apparently transfers an overlooked epigenetic diabetogenic program

  2. Crosstalk between mTORC1 and cAMP Signaling

    Science.gov (United States)

    2014-07-01

    in response to inflammation. (c) Glycogen synthase kinase (GSK)3-b, which is regulated by Wnt signaling, phosphorylates TSC2 and increases its GAP...by AMPK acts as a primer for the phos- phorylation and activation of TSC2 function by glycogen synthase kinase (GSK)3-b. Wnt signaling promotes mTOR...homologous to any of the known GEF catalytic domains. Nucleotide- free rather than nucleotide- bound RAGA/B preferentially interacts with Ragulator, a

  3. Sestrin2 inhibits mTORC1 through modulation of GATOR complexes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeong Sig; Ro, Seung-Hyun; Kim, Myungjin; Park, Hwan-Woo; Semple, Ian A.; Park, Haeli; Cho, Uhn-Soo; Wang, Wei; Guan, Kun-Liang; Karin, Michael; Lee, Jun Hee (Michigan); (UCSD)

    2015-03-30

    Sestrins are stress-inducible metabolic regulators that suppress a wide range of age- and obesity-associated pathologies, many of which are due to mTORC1 overactivation. Upon various stresses, the Sestrins inhibit mTORC1 activity through an indirect mechanism that is still unclear. GATORs are recently identified protein complexes that regulate the activity of RagB, a small GTPase essential for mTORC1 activation. GATOR1 is a GTPase activating protein (GAP) for RagB whereas GATOR2 functions as an inhibitor of GATOR1. However, how the GATORs are physiologically regulated is unknown. Here we show that Sestrin2 binds to GATOR2, and liberates GATOR1 from GATOR2-mediated inhibition. Released GATOR1 subsequently binds to and inactivates RagB, ultimately resulting in mTORC1 suppression. Consistent with this biochemical mechanism, genetic ablation of GATOR1 nullifies the mTORC1-inhibiting effect of Sestrin2 in both cell culture and Drosophila models. Collectively, we elucidate a new signaling cascade composed of Sestrin2-GATOR2-GATOR1-RagB that mediates stress-dependent suppression of mTORC1 activity.

  4. Prolonged calorie restriction downregulates skeletal muscle mTORC1 signaling independent of dietary protein intake and associated microRNA expression

    Directory of Open Access Journals (Sweden)

    Lee M Margolis

    2016-10-01

    Full Text Available Short-term (5-10 days calorie restriction (CR downregulates muscle protein synthesis, with consumption of a high protein-based diet attenuating this decline. Benefit of increase protein intake is believed to be due to maintenance of amino acid-mediated anabolic signaling through the mechanistic target of rapamycin complex 1 (mTORC1, however, there is limited evidence to support this contention. The purpose of this investigation was to determine the effects of prolonged CR and high protein diets on skeletal muscle mTORC1 signaling and expression of associated microRNA (miR. 12-wk old male Sprague Dawley rats consumed ad libitum (AL or calorie restricted (CR; 40% adequate (10%, AIN-93M or high (32% protein milk-based diets for 16 weeks. Body composition was determined using dual energy X-ray absorptiometry and muscle protein content was calculated from muscle homogenate protein concentrations expressed relative to fat-free mass to estimate protein content. Western blot and RT-qPCR were used to determine mTORC1 signaling and mRNA and miR expression in fasted mixed gastrocnemius. Independent of dietary protein intake, muscle protein content was 38% lower (P < 0.05 in CR compared to AL. Phosphorylation and total Akt, mTOR, rpS6 and p70S6K were lower (P < 0.05 in CR versus AL, and total rpS6 was associated with muscle protein content (r = 0.64, r2 = 0.36. Skeletal muscle miR expression was not altered by either energy or protein intake. This study provides evidence that chronic CR attenuates muscle protein content by downregulating mTORC1 signaling. This response is independent of skeletal muscle miR and dietary protein.

  5. PIK3CA-mutated melanoma cells rely on cooperative signaling through mTORC1/2 for sustained proliferation.

    Science.gov (United States)

    Silva, Jillian M; Deuker, Marian M; Baguley, Bruce C; McMahon, Martin

    2017-05-01

    Malignant conversion of BRAF- or NRAS-mutated melanocytes into melanoma cells can be promoted by PI3'-lipid signaling. However, the mechanism by which PI3'-lipid signaling cooperates with mutationally activated BRAF or NRAS has not been adequately explored. Using human NRAS- or BRAF-mutated melanoma cells that co-express mutationally activated PIK3CA, we explored the contribution of PI3'-lipid signaling to cell proliferation. Despite mutational activation of PIK3CA, melanoma cells were more sensitive to the biochemical and antiproliferative effects of broader spectrum PI3K inhibitors than to an α-selective PI3K inhibitor. Combined pharmacological inhibition of MEK1/2 and PI3K signaling elicited more potent antiproliferative effects and greater inhibition of the cell division cycle compared to single-agent inhibition of either pathway alone. Analysis of signaling downstream of MEK1/2 or PI3K revealed that these pathways cooperate to regulate cell proliferation through mTORC1-mediated effects on ribosomal protein S6 and 4E-BP1 phosphorylation in an AKT-dependent manner. Although PI3K inhibition resulted in cytostatic effects on xenografted NRAS Q61H /PIK3CA H1047R melanoma, combined inhibition of MEK1/2 plus PI3K elicited significant melanoma regression. This study provides insights as to how mutationally activated PIK3CA acts in concert with MEK1/2 signaling to cooperatively regulate mTORC1/2 to sustain PIK3CA-mutated melanoma proliferation. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Hepatic mTORC1 controls locomotor activity, body temperature, and lipid metabolism through FGF21

    Science.gov (United States)

    Cornu, Marion; Oppliger, Wolfgang; Albert, Verena; Robitaille, Aaron M.; Trapani, Francesca; Quagliata, Luca; Fuhrer, Tobias; Sauer, Uwe; Terracciano, Luigi; Hall, Michael N.

    2014-01-01

    The liver is a key metabolic organ that controls whole-body physiology in response to nutrient availability. Mammalian target of rapamycin (mTOR) is a nutrient-activated kinase and central controller of growth and metabolism that is negatively regulated by the tumor suppressor tuberous sclerosis complex 1 (TSC1). To investigate the role of hepatic mTOR complex 1 (mTORC1) in whole-body physiology, we generated liver-specific Tsc1 (L-Tsc1 KO) knockout mice. L-Tsc1 KO mice displayed reduced locomotor activity, body temperature, and hepatic triglyceride content in a rapamycin-sensitive manner. Ectopic activation of mTORC1 also caused depletion of hepatic and plasma glutamine, leading to peroxisome proliferator–activated receptor γ coactivator-1α (PGC-1α)–dependent fibroblast growth factor 21 (FGF21) expression in the liver. Injection of glutamine or knockdown of PGC-1α or FGF21 in the liver suppressed the behavioral and metabolic defects due to mTORC1 activation. Thus, mTORC1 in the liver controls whole-body physiology through PGC-1α and FGF21. Finally, mTORC1 signaling correlated with FGF21 expression in human liver tumors, suggesting that treatment of glutamine-addicted cancers with mTOR inhibitors might have beneficial effects at both the tumor and whole-body level. PMID:25082895

  7. Dual regulation of cadmium-induced apoptosis by mTORC1 through selective induction of IRE1 branches in unfolded protein response.

    Directory of Open Access Journals (Sweden)

    Hironori Kato

    Full Text Available Cadmium (Cd causes generation of reactive oxygen species (ROS that trigger renal tubular injury. We found that rapamycin, an inhibitor of mTORC1, attenuated Cd-induced apoptosis in renal tubular cells. Knockdown of Raptor, a positive regulator of mTORC1, also had the similar effect. However, rapamycin did not alter generation of ROS, suggesting that mTORC1 is a target downstream of ROS. Indeed, ROS caused activation of mTORC1, which contributed to induction of a selective branch of the unfolded protein response (UPR; i.e., the IRE1 pathway. Although Cd triggered three major UPR pathways, activation of mTORC1 by Cd did not contribute to induction of the PERK-eIF2α and ATF6 pathways. Consistently, knockdown of Raptor caused suppression of JNK without affecting the PERK-eIF2α pathway in Cd-exposed cells. Knockdown of TSC2, a negative regulator of mTORC1, caused activation of mTORC1 and enhanced Cd induction of the IRE1-JNK pathway and apoptosis without affecting other UPR branches. Inhibition of IRE1α kinase led to suppression of JNK activity and apoptosis in Cd-treated cells. Dominant-negative inhibition of JNK also suppressed Cd-induced apoptosis. In contrast, inhibition of IRE1α endoribonuclease activity or downstream XBP1 modestly enhanced Cd-induced apoptosis. In vivo, administration with rapamycin suppressed activation of mTORC1 and JNK, but not eIF2α, in the kidney of Cd-treated mice. It was correlated with attenuation of tubular injury and apoptotic cell death in the tubules. These results elucidate dual regulation of Cd-induced renal injury by mTORC1 through selective induction of IRE1 signaling.

  8. Enhanced skeletal muscle ribosome biogenesis, yet attenuated mTORC1 and ribosome biogenesis-related signalling, following short-term concurrent versus single-mode resistance training.

    Science.gov (United States)

    Fyfe, Jackson J; Bishop, David J; Bartlett, Jonathan D; Hanson, Erik D; Anderson, Mitchell J; Garnham, Andrew P; Stepto, Nigel K

    2018-01-12

    Combining endurance training with resistance training (RT) may attenuate skeletal muscle hypertrophic adaptation versus RT alone; however, the underlying mechanisms are unclear. We investigated changes in markers of ribosome biogenesis, a process linked with skeletal muscle hypertrophy, following concurrent training versus RT alone. Twenty-three males underwent eight weeks of RT, either performed alone (RT group, n = 8), or combined with either high-intensity interval training (HIT+RT group, n = 8), or moderate-intensity continuous training (MICT+RT group, n = 7). Muscle samples (vastus lateralis) were obtained before training, and immediately before, 1 h and 3 h after the final training session. Training-induced changes in basal expression of the 45S ribosomal RNA (rRNA) precursor (45S pre-rRNA), and 5.8S and 28S mature rRNAs, were greater with concurrent training versus RT. However, during the final training session, RT further increased both mTORC1 (p70S6K1 and rps6 phosphorylation) and 45S pre-rRNA transcription-related signalling (TIF-1A and UBF phosphorylation) versus concurrent training. These data suggest that when performed in a training-accustomed state, RT induces further increases mTORC1 and ribosome biogenesis-related signalling in human skeletal muscle versus concurrent training; however, changes in ribosome biogenesis markers were more favourable following a period of short-term concurrent training versus RT performed alone.

  9. The E3 ubiquitin ligase protein associated with Myc (Pam) regulates mammalian/mechanistic target of rapamycin complex 1 (mTORC1) signaling in vivo through N- and C-terminal domains.

    Science.gov (United States)

    Han, Sangyeul; Kim, Sun; Bahl, Samira; Li, Lin; Burande, Clara F; Smith, Nicole; James, Marianne; Beauchamp, Roberta L; Bhide, Pradeep; DiAntonio, Aaron; Ramesh, Vijaya

    2012-08-31

    Pam and its homologs (the PHR protein family) are large E3 ubiquitin ligases that function to regulate synapse formation and growth in mammals, zebrafish, Drosophila, and Caenorhabditis elegans. Phr1-deficient mouse models (Phr1(Δ8,9) and Phr1(Magellan), with deletions in the N-terminal putative guanine exchange factor region and the C-terminal ubiquitin ligase region, respectively) exhibit axon guidance/outgrowth defects and striking defects of major axon tracts in the CNS. Our earlier studies identified Pam to be associated with tuberous sclerosis complex (TSC) proteins, ubiquitinating TSC2 and regulating mammalian/mechanistic target of rapamycin (mTOR) signaling. Here, we examine the potential involvement of the TSC/mTOR complex 1(mTORC1) signaling pathway in Phr1-deficient mouse models. We observed attenuation of mTORC1 signaling in the brains of both Phr1(Δ8,9) and Phr1(Magellan) mouse models. Our results establish that Pam regulates TSC/mTOR signaling in vitro and in vivo through two distinct domains. To further address whether Pam regulates mTORC1 through two functionally independent domains, we undertook heterozygous mutant crossing between Phr1(Δ8,9) and Phr1(Magellan) mice to generate a compound heterozygous model to determine whether these two domains can complement each other. mTORC1 signaling was not attenuated in the brains of double mutants (Phr1(Δ8,9/Mag)), confirming that Pam displays dual regulation of the mTORC1 pathway through two functional domains. Our results also suggest that although dysregulation of mTORC1 signaling may be responsible for the corpus callosum defects, other neurodevelopmental defects observed with Phr1 deficiency are independent of mTORC1 signaling. The ubiquitin ligase complex containing Pam-Fbxo45 likely targets additional synaptic and axonal proteins, which may explain the overlapping neurodevelopmental defects observed in Phr1 and Fbxo45 deficiency.

  10. Simultaneous inhibition of mTOR-containing complex 1 (mTORC1 and MNK induces apoptosis of cutaneous T-cell lymphoma (CTCL cells.

    Directory of Open Access Journals (Sweden)

    Michal Marzec

    Full Text Available BACKGROUND: mTOR kinase forms the mTORC1 complex by associating with raptor and other proteins and affects a number of key cell functions. mTORC1 activates p70S6kinase 1 (p70S6K1 and inhibits 4E-binding protein 1 (4E-BP1. In turn, p70S6K1 phosphorylates a S6 protein of the 40S ribosomal subunit (S6rp and 4E-BP1, with the latter negatively regulating eukaryotic initiation factor 4E (eIF-4E. MNK1 and MNK2 kinases phosphorylate and augment activity of eIF4E. Rapamycin and its analogs are highly specific, potent, and relatively non-toxic inhibitors of mTORC1. Although mTORC1 activation is present in many types of malignancies, rapamycin-type inhibitors shows relatively limited clinical efficacy as single agents. Initially usually indolent, CTCL displays a tendency to progress to the aggressive forms with limited response to therapy and poor prognosis. Our previous study (M. Marzec et al. 2008 has demonstrated that CTCL cells display mTORC1 activation and short-term treatment of CTCL-derived cells with rapamycin suppressed their proliferation and had little effect on the cell survival. METHODS: Cells derived from CTCL were treated with mTORC1 inhibitor rapamycin and MNK inhibitor and evaluated for inhibition of the mTORC1 signaling pathway and cell growth and survival. RESULTS: Whereas the treatment with rapamycin persistently inhibited mTORC1 signaling, it suppressed only partially the cell growth. MNK kinase mediated the eIF4E phosphorylation and inhibition or depletion of MNK markedly suppressed proliferation of the CTCL cells when combined with the rapamycin-mediated inhibition of mTORC1. While MNK inhibition alone mildly suppressed the CTCL cell growth, the combined MNK and mTORC1 inhibition totally abrogated the growth. Similarly, MNK inhibitor alone displayed a minimal pro-apoptotic effect; in combination with rapamycin it triggered profound cell apoptosis. CONCLUSIONS: These findings indicate that the combined inhibition of mTORC1 and MNK may

  11. Concurrent exercise incorporating high-intensity interval or continuous training modulates mTORC1 signaling and microRNA expression in human skeletal muscle.

    Science.gov (United States)

    Fyfe, Jackson J; Bishop, David J; Zacharewicz, Evelyn; Russell, Aaron P; Stepto, Nigel K

    2016-06-01

    We compared the effects of concurrent exercise, incorporating either high-intensity interval training (HIT) or moderate-intensity continuous training (MICT), on mechanistic target of rapamycin complex 1 (mTORC1) signaling and microRNA expression in skeletal muscle, relative to resistance exercise (RE) alone. Eight males (mean ± SD: age, 27 ± 4 yr; V̇o2 peak , 45.7 ± 9 ml·kg(-1)·min(-1)) performed three experimental trials in a randomized order: 1) RE (8 × 5 leg press repetitions at 80% 1-repetition maximum) performed alone and RE preceded by either 2) HIT cycling [10 × 2 min at 120% lactate threshold (LT); HIT + RE] or 3) work-matched MICT cycling (30 min at 80% LT; MICT + RE). Vastus lateralis muscle biopsies were obtained immediately before RE, either without (REST) or with (POST) preceding endurance exercise and +1 h (RE + 1 h) and +3 h (RE + 3 h) after RE. Prior HIT and MICT similarly reduced muscle glycogen content and increased ACC(Ser79) and p70S6K(Thr389) phosphorylation before subsequent RE (i.e., at POST). Compared with MICT, HIT induced greater mTOR(Ser2448) and rps6(Ser235/236) phosphorylation at POST. RE-induced increases in p70S6K and rps6 phosphorylation were not influenced by prior HIT or MICT; however, mTOR phosphorylation was reduced at RE + 1 h for MICT + RE vs. both HIT + RE and RE. Expression of miR-133a, miR-378, and miR-486 was reduced at RE + 1 h for HIT + RE vs. both MICT + RE and RE. Postexercise mTORC1 signaling following RE is therefore not compromised by prior HIT or MICT, and concurrent exercise incorporating HIT, but not MICT, reduces postexercise expression of miRNAs implicated in skeletal muscle adaptation to RE. Copyright © 2016 the American Physiological Society.

  12. A genome-wide siRNA screen reveals multiple mTORC1 independent signaling pathways regulating autophagy under normal nutritional conditions.

    Science.gov (United States)

    Lipinski, Marta M; Hoffman, Greg; Ng, Aylwin; Zhou, Wen; Py, Bénédicte F; Hsu, Emily; Liu, Xuxin; Eisenberg, Jason; Liu, Jun; Blenis, John; Xavier, Ramnik J; Yuan, Junying

    2010-06-15

    Autophagy is a cellular catabolic mechanism that plays an essential function in protecting multicellular eukaryotes from neurodegeneration, cancer, and other diseases. However, we still know very little about mechanisms regulating autophagy under normal homeostatic conditions when nutrients are not limiting. In a genome-wide human siRNA screen, we demonstrate that under normal nutrient conditions upregulation of autophagy requires the type III PI3 kinase, but not inhibition of mTORC1, the essential negative regulator of starvation-induced autophagy. We show that a group of growth factors and cytokines inhibit the type III PI3 kinase through multiple pathways, including the MAPK-ERK1/2, Stat3, Akt/Foxo3, and CXCR4/GPCR, which are all known to positively regulate cell growth and proliferation. Our study suggests that the type III PI3 kinase integrates diverse signals to regulate cellular levels of autophagy, and that autophagy and cell proliferation may represent two alternative cell fates that are regulated in a mutually exclusive manner. Copyright 2010 Elsevier Inc. All rights reserved.

  13. Regulation of mTORC1 signaling by Src kinase activity is Akt1-independent in RSV-transformed cells

    Czech Academy of Sciences Publication Activity Database

    Vojtěchová, Martina; Turečková, Jolana; Kučerová, Dana; Šloncová, Eva; Vachtenheim, J.; Tuháčková, Zdena

    2008-01-01

    Roč. 10, č. 2 (2008), s. 99-107 ISSN 1522-8002 R&D Projects: GA ČR GA301/04/0550 Institutional research plan: CEZ:AV0Z50520514 Keywords : Akt/PKB * mTOR C1 signaling pathway * Src Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.191, year: 2008

  14. Intake of a Ketone Ester Drink during Recovery from Exercise Promotes mTORC1 Signaling but Not Glycogen Resynthesis in Human Muscle.

    Science.gov (United States)

    Vandoorne, Tijs; De Smet, Stefan; Ramaekers, Monique; Van Thienen, Ruud; De Bock, Katrien; Clarke, Kieran; Hespel, Peter

    2017-01-01

    Purpose: Ketone bodies are energy substrates produced by the liver during prolonged fasting or low-carbohydrate diet. The ingestion of a ketone ester (KE) rapidly increases blood ketone levels independent of nutritional status. KE has recently been shown to improve exercise performance, but whether it can also promote post-exercise muscle protein or glycogen synthesis is unknown. Methods: Eight healthy trained males participated in a randomized double-blind placebo-controlled crossover study. In each session, subjects undertook a bout of intense one-leg glycogen-depleting exercise followed by a 5-h recovery period during which they ingested a protein/carbohydrate mixture. Additionally, subjects ingested a ketone ester (KE) or an isocaloric placebo (PL). Results: KE intake did not affect muscle glycogen resynthesis, but more rapidly lowered post-exercise AMPK phosphorylation and resulted in higher mTORC1 activation, as evidenced by the higher phosphorylation of its main downstream targets S6K1 and 4E-BP1. As enhanced mTORC1 activation following KE suggests higher protein synthesis rates, we used myogenic C 2 C 12 cells to further confirm that ketone bodies increase both leucine-mediated mTORC1 activation and protein synthesis in muscle cells. Conclusion: Our results indicate that adding KE to a standard post-exercise recovery beverage enhances the post-exercise activation of mTORC1 but does not affect muscle glycogen resynthesis in young healthy volunteers. In vitro , we confirmed that ketone bodies potentiate the increase in mTORC1 activation and protein synthesis in leucine-stimulated myotubes. Whether, chronic oral KE intake during recovery from exercise can facilitate training-induced muscular adaptation and remodeling need to be further investigated.

  15. Intake of a Ketone Ester Drink during Recovery from Exercise Promotes mTORC1 Signaling but Not Glycogen Resynthesis in Human Muscle

    Directory of Open Access Journals (Sweden)

    Tijs Vandoorne

    2017-05-01

    Full Text Available Purpose: Ketone bodies are energy substrates produced by the liver during prolonged fasting or low-carbohydrate diet. The ingestion of a ketone ester (KE rapidly increases blood ketone levels independent of nutritional status. KE has recently been shown to improve exercise performance, but whether it can also promote post-exercise muscle protein or glycogen synthesis is unknown.Methods: Eight healthy trained males participated in a randomized double-blind placebo-controlled crossover study. In each session, subjects undertook a bout of intense one-leg glycogen-depleting exercise followed by a 5-h recovery period during which they ingested a protein/carbohydrate mixture. Additionally, subjects ingested a ketone ester (KE or an isocaloric placebo (PL.Results: KE intake did not affect muscle glycogen resynthesis, but more rapidly lowered post-exercise AMPK phosphorylation and resulted in higher mTORC1 activation, as evidenced by the higher phosphorylation of its main downstream targets S6K1 and 4E-BP1. As enhanced mTORC1 activation following KE suggests higher protein synthesis rates, we used myogenic C2C12 cells to further confirm that ketone bodies increase both leucine-mediated mTORC1 activation and protein synthesis in muscle cells.Conclusion: Our results indicate that adding KE to a standard post-exercise recovery beverage enhances the post-exercise activation of mTORC1 but does not affect muscle glycogen resynthesis in young healthy volunteers. In vitro, we confirmed that ketone bodies potentiate the increase in mTORC1 activation and protein synthesis in leucine-stimulated myotubes. Whether, chronic oral KE intake during recovery from exercise can facilitate training-induced muscular adaptation and remodeling need to be further investigated.

  16. The novel mTORC1/2 dual inhibitor INK-128 suppresses survival and proliferation of primary and transformed human pancreatic cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Lou, Hai-zhou [Department of Medical Oncology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou 310016 (China); Weng, Xiao-chuan [Department of Anesthesiology, Hangzhou Xia-sha Hospital, Hangzhou 310018 (China); Pan, Hong-ming; Pan, Qin [Department of Medical Oncology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou 310016 (China); Sun, Peng [Department of Medical Oncology, Sun Yat-Sen University Cancer Center, Guangzhou 510060 (China); Liu, Li-li [Department of Medical Oncology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou 310016 (China); Chen, Bin, E-mail: chenbinhangzhou126@126.com [Department of Hepatopancreatobiliary Surgery, First People’s Hospital of Hangzhou, Hangzhou 310006 (China)

    2014-07-25

    Highlights: • INK-128 inhibits the survival and growth of human pancreatic cancer cells. • INK-128 induced pancreatic cancer cell apoptosis and necrosis simultaneously. • INK-128 blocks mTORC1/2 activation simultaneously in pancreatic cancer cells. • INK-128 down-regulates cyclin D1 and causes pancreatic cancer cell cycle arrest. • INK-128 significantly increases sensitivity of pancreatic cancer cells to gemcitabine. - Abstract: Pancreatic cancer has one of worst prognosis among all human malignancies around the world, the development of novel and more efficient anti-cancer agents against this disease is urgent. In the current study, we tested the potential effect of INK-128, a novel mammalian target of rapamycin (mTOR) complex 1 and 2 (mTORC1/2) dual inhibitor, against pancreatic cancer cells in vitro. Our results demonstrated that INK-128 concentration- and time-dependently inhibited the survival and growth of pancreatic cancer cells (both primary cells and transformed cells). INK-128 induced pancreatic cancer cell apoptosis and necrosis simultaneously. Further, INK-128 dramatically inhibited phosphorylation of 4E-binding protein 1 (4E-BP1), ribosomal S6 kinase 1 (S6K1) and Akt at Ser 473 in pancreatic cancer cells. Meanwhile, it downregulated cyclin D1 expression and caused cell cycle arrest. Finally, we found that a low concentration of INK-128 significantly increased the sensitivity of pancreatic cancer cells to gemcitabine. Together, our in vitro results suggest that INK-128 might be further investigated as a novel anti-cancer agent or chemo-adjuvant for pancreatic cancer treatment.

  17. The novel mTORC1/2 dual inhibitor INK-128 suppresses survival and proliferation of primary and transformed human pancreatic cancer cells

    International Nuclear Information System (INIS)

    Lou, Hai-zhou; Weng, Xiao-chuan; Pan, Hong-ming; Pan, Qin; Sun, Peng; Liu, Li-li; Chen, Bin

    2014-01-01

    Highlights: • INK-128 inhibits the survival and growth of human pancreatic cancer cells. • INK-128 induced pancreatic cancer cell apoptosis and necrosis simultaneously. • INK-128 blocks mTORC1/2 activation simultaneously in pancreatic cancer cells. • INK-128 down-regulates cyclin D1 and causes pancreatic cancer cell cycle arrest. • INK-128 significantly increases sensitivity of pancreatic cancer cells to gemcitabine. - Abstract: Pancreatic cancer has one of worst prognosis among all human malignancies around the world, the development of novel and more efficient anti-cancer agents against this disease is urgent. In the current study, we tested the potential effect of INK-128, a novel mammalian target of rapamycin (mTOR) complex 1 and 2 (mTORC1/2) dual inhibitor, against pancreatic cancer cells in vitro. Our results demonstrated that INK-128 concentration- and time-dependently inhibited the survival and growth of pancreatic cancer cells (both primary cells and transformed cells). INK-128 induced pancreatic cancer cell apoptosis and necrosis simultaneously. Further, INK-128 dramatically inhibited phosphorylation of 4E-binding protein 1 (4E-BP1), ribosomal S6 kinase 1 (S6K1) and Akt at Ser 473 in pancreatic cancer cells. Meanwhile, it downregulated cyclin D1 expression and caused cell cycle arrest. Finally, we found that a low concentration of INK-128 significantly increased the sensitivity of pancreatic cancer cells to gemcitabine. Together, our in vitro results suggest that INK-128 might be further investigated as a novel anti-cancer agent or chemo-adjuvant for pancreatic cancer treatment

  18. Receptor-recognized α₂-macroglobulin binds to cell surface-associated GRP78 and activates mTORC1 and mTORC2 signaling in prostate cancer cells.

    Directory of Open Access Journals (Sweden)

    Uma K Misra

    Full Text Available OBJECTIVE: Tetrameric α(2-macroglobulin (α(2M, a plasma panproteinase inhibitor, is activated upon interaction with a proteinase, and undergoes a major conformational change exposing a receptor recognition site in each of its subunits. Activated α(2M (α(2M* binds to cancer cell surface GRP78 and triggers proliferative and antiapoptotic signaling. We have studied the role of α(2M* in the regulation of mTORC1 and TORC2 signaling in the growth of human prostate cancer cells. METHODS: Employing immunoprecipitation techniques and Western blotting as well as kinase assays, activation of the mTORC1 and mTORC2 complexes, as well as down stream targets were studied. RNAi was also employed to silence expression of Raptor, Rictor, or GRP78 in parallel studies. RESULTS: Stimulation of cells with α(2M* promotes phosphorylation of mTOR, TSC2, S6-Kinase, 4EBP, Akt(T308, and Akt(S473 in a concentration and time-dependent manner. Rheb, Raptor, and Rictor also increased. α(2M* treatment of cells elevated mTORC1 kinase activity as determined by kinase assays of mTOR or Raptor immunoprecipitates. mTORC1 activity was sensitive to LY294002 and rapamycin or transfection of cells with GRP78 dsRNA. Down regulation of Raptor expression by RNAi significantly reduced α(2M*-induced S6-Kinase phosphorylation at T389 and kinase activity in Raptor immunoprecipitates. α(2M*-treated cells demonstrate about a twofold increase in mTORC2 kinase activity as determined by kinase assay of Akt(S473 phosphorylation and levels of p-Akt(S473 in mTOR and Rictor immunoprecipitates. mTORC2 activity was sensitive to LY294002 and transfection of cells with GRP78 dsRNA, but insensitive to rapamycin. Down regulation of Rictor expression by RNAi significantly reduces α(2M*-induced phosphorylation of Akt(S473 phosphorylation in Rictor immunoprecipitates. CONCLUSION: Binding of α(2M* to prostate cancer cell surface GRP78 upregulates mTORC1 and mTORC2 activation and promotes protein

  19. PGE2-induced colon cancer growth is mediated by mTORC1

    International Nuclear Information System (INIS)

    Dufour, Marc; Faes, Seraina; Dormond-Meuwly, Anne; Demartines, Nicolas; Dormond, Olivier

    2014-01-01

    Highlights: • PGE 2 activates mTORC1 in colon cancer cells. • Inhibition of mTORC1 blocks PGE 2 induced colon cancer cell growth. • mTORC1 is a signaling intermediary in PGE 2 induced colon cancer cell responses. - Abstract: The inflammatory prostaglandin E 2 (PGE 2 ) cytokine plays a key role in the development of colon cancer. Several studies have shown that PGE 2 directly induces the growth of colon cancer cells and furthermore promotes tumor angiogenesis by increasing the production of the vascular endothelial growth factor (VEGF). The signaling intermediaries implicated in these processes have however not been fully characterized. In this report, we show that the mechanistic target of rapamycin complex 1 (mTORC1) plays an important role in PGE 2 -induced colon cancer cell responses. Indeed, stimulation of LS174T cells with PGE 2 increased mTORC1 activity as observed by the augmentation of S6 ribosomal protein phosphorylation, a downstream effector of mTORC1. The PGE 2 EP 4 receptor was responsible for transducing the signal to mTORC1. Moreover, PGE 2 increased colon cancer cell proliferation as well as the growth of colon cancer cell colonies grown in matrigel and blocking mTORC1 by rapamycin or ATP-competitive inhibitors of mTOR abrogated these effects. Similarly, the inhibition of mTORC1 by downregulation of its component raptor using RNA interference blocked PGE 2 -induced LS174T cell growth. Finally, stimulation of LS174T cells with PGE 2 increased VEGF production which was also prevented by mTORC1 inhibition. Taken together, these results show that mTORC1 is an important signaling intermediary in PGE 2 mediated colon cancer cell growth and VEGF production. They further support a role for mTORC1 in inflammation induced tumor growth

  20. Recent Advances in Understanding Amino Acid Sensing Mechanisms that Regulate mTORC1

    Directory of Open Access Journals (Sweden)

    Liufeng Zheng

    2016-09-01

    Full Text Available The mammalian target of rapamycin (mTOR is the central regulator of mammalian cell growth, and is essential for the formation of two structurally and functionally distinct complexes: mTORC1 and mTORC2. mTORC1 can sense multiple cues such as nutrients, energy status, growth factors and hormones to control cell growth and proliferation, angiogenesis, autophagy, and metabolism. As one of the key environmental stimuli, amino acids (AAs, especially leucine, glutamine and arginine, play a crucial role in mTORC1 activation, but where and how AAs are sensed and signal to mTORC1 are not fully understood. Classically, AAs activate mTORC1 by Rag GTPases which recruit mTORC1 to lysosomes, where AA signaling initiates. Plasma membrane transceptor L amino acid transporter 1 (LAT1-4F2hc has dual transporter-receptor function that can sense extracellular AA availability upstream of mTORC1. The lysosomal AA sensors (PAT1 and SLC38A9 and cytoplasmic AA sensors (LRS, Sestrin2 and CASTOR1 also participate in regulating mTORC1 activation. Importantly, AAs can be sensed by plasma membrane receptors, like G protein-coupled receptor (GPCR T1R1/T1R3, and regulate mTORC1 without being transported into the cells. Furthermore, AA-dependent mTORC1 activation also initiates within Golgi, which is regulated by Golgi-localized AA transporter PAT4. This review provides an overview of the research progress of the AA sensing mechanisms that regulate mTORC1 activity.

  1. Sestrins Inhibit mTORC1 Kinase Activation through the GATOR Complex

    Directory of Open Access Journals (Sweden)

    Anita Parmigiani

    2014-11-01

    Full Text Available The mechanistic target of rapamycin complex 1 (mTORC1 kinase is a sensor of different environmental conditions and regulator of cell growth, metabolism, and autophagy. mTORC1 is activated by Rag GTPases, working as RagA:RagB and RagC:RagD heterodimers. Rags control mTORC1 activity by tethering mTORC1 to the lysosomes where it is activated by Rheb GTPase. RagA:RagB, active in its GTP-bound form, is inhibited by GATOR1 complex, a GTPase-activating protein, and GATOR1 is in turn negatively regulated by GATOR2 complex. Sestrins are stress-responsive proteins that inhibit mTORC1 via activation of AMP-activated protein kinase (AMPK and tuberous sclerosis complex. Here we report an AMPK-independent mechanism of mTORC1 inhibition by Sestrins mediated by their interaction with GATOR2. As a result of this interaction, the Sestrins suppress mTOR lysosomal localization in a Rag-dependent manner. This mechanism is potentially involved in mTORC1 regulation by amino acids, rotenone, and tunicamycin, connecting stress response with mTORC1 inhibition.

  2. Macropinocytosis, mTORC1 and cellular growth control.

    Science.gov (United States)

    Yoshida, Sei; Pacitto, Regina; Inoki, Ken; Swanson, Joel

    2018-04-01

    The growth and proliferation of metazoan cells are driven by cellular nutrient status and by extracellular growth factors. Growth factor receptors on cell surfaces initiate biochemical signals that increase anabolic metabolism and macropinocytosis, an actin-dependent endocytic process in which relatively large volumes of extracellular solutes and nutrients are internalized and delivered efficiently into lysosomes. Macropinocytosis is prominent in many kinds of cancer cells, and supports the growth of cells transformed by oncogenic K-Ras. Growth factor receptor signaling and the overall metabolic status of the cell are coordinated in the cytoplasm by the mechanistic target-of-rapamycin complex-1 (mTORC1), which positively regulates protein synthesis and negatively regulates molecular salvage pathways such as autophagy. mTORC1 is activated by two distinct Ras-related small GTPases, Rag and Rheb, which associate with lysosomal membranes inside the cell. Rag recruits mTORC1 to the lysosomal surface where Rheb directly binds to and activates mTORC1. Rag is activated by both lysosomal luminal and cytosolic amino acids; Rheb activation requires phosphoinositide 3-kinase, Akt, and the tuberous sclerosis complex-1/2. Signals for activation of Rag and Rheb converge at the lysosomal membrane, and several lines of evidence support the idea that growth factor-dependent endocytosis facilitates amino acid transfer into the lysosome leading to the activation of Rag. This review summarizes evidence that growth factor-stimulated macropinocytosis is essential for amino acid-dependent activation of mTORC1, and that increased solute accumulation by macropinocytosis in transformed cells supports unchecked cell growth.

  3. Equivalent benefit of mTORC1 blockade and combined PI3K-mTOR blockade in a mouse model of tuberous sclerosis

    Directory of Open Access Journals (Sweden)

    Pollizzi Kristen

    2009-06-01

    Full Text Available Abstract Background Tuberous sclerosis (TSC is a hamartoma syndrome in which renal and lung tumors cause the greatest morbidity. Loss of either TSC1 or TSC2 in TSC hamartomas leads to activation of mTORC1 and suppression of AKT. Recent studies indicate that inhibition of mTORC1 with RAD001 (everolimus leads to rebound activation of AKT, which could protect tumors from drug-induced cell death. Here we examine the potential benefit of inhibition of both mTOR and AKT signaling in a mouse model of TSC, using a dual pan class I PI3K/mTOR catalytic small molecule inhibitor NVP-BEZ235. Results Using ENU to enhance Tsc2+- kidney tumor development, both RAD001 (10 mg/kg PO 5 d/week and NVP-BEZ235 (45 mg/kg PO QD had equivalent effects in suppressing tumor development during a 4 week treatment period, with a 99% reduction in tumor cell mass. Marked reduction in activation of mTORC1, induction of cell cycle arrest, and absence of apoptotic cell death was seen in mice treated with either drug. However, when either was discontinued, there was prompt recovery of tumor growth, with extensive proliferation. Conclusion Both mTORC1 blockade alone and combined PI3K-mTOR blockade lead to suppression of tumor development but not tumor elimination in this TSC model.

  4. Milk—A Nutrient System of Mammalian Evolution Promoting mTORC1-Dependent Translation

    Directory of Open Access Journals (Sweden)

    Bodo C. Melnik

    2015-07-01

    Full Text Available Based on own translational research of the biochemical and hormonal effects of cow’s milk consumption in humans, this review presents milk as a signaling system of mammalian evolution that activates the nutrient-sensitive kinase mechanistic target of rapamycin complex 1 (mTORC1, the pivotal regulator of translation. Milk, a mammary gland-derived secretory product, is required for species-specific gene-nutrient interactions that promote appropriate growth and development of the newborn mammal. This signaling system is highly conserved and tightly controlled by the lactation genome. Milk is sufficient to activate mTORC1, the crucial regulator of protein, lipid, and nucleotide synthesis orchestrating anabolism, cell growth and proliferation. To fulfill its mTORC1-activating function, milk delivers four key metabolic messengers: (1 essential branched-chain amino acids (BCAAs; (2 glutamine; (3 palmitic acid; and (4 bioactive exosomal microRNAs, which in a synergistical fashion promote mTORC1-dependent translation. In all mammals except Neolithic humans, postnatal activation of mTORC1 by milk intake is restricted to the postnatal lactation period. It is of critical concern that persistent hyperactivation of mTORC1 is associated with aging and the development of age-related disorders such as obesity, type 2 diabetes mellitus, cancer, and neurodegenerative diseases. Persistent mTORC1 activation promotes endoplasmic reticulum (ER stress and drives an aimless quasi-program, which promotes aging and age-related diseases.

  5. Milk—A Nutrient System of Mammalian Evolution Promoting mTORC1-Dependent Translation

    Science.gov (United States)

    Melnik, Bodo C.

    2015-01-01

    Based on own translational research of the biochemical and hormonal effects of cow’s milk consumption in humans, this review presents milk as a signaling system of mammalian evolution that activates the nutrient-sensitive kinase mechanistic target of rapamycin complex 1 (mTORC1), the pivotal regulator of translation. Milk, a mammary gland-derived secretory product, is required for species-specific gene-nutrient interactions that promote appropriate growth and development of the newborn mammal. This signaling system is highly conserved and tightly controlled by the lactation genome. Milk is sufficient to activate mTORC1, the crucial regulator of protein, lipid, and nucleotide synthesis orchestrating anabolism, cell growth and proliferation. To fulfill its mTORC1-activating function, milk delivers four key metabolic messengers: (1) essential branched-chain amino acids (BCAAs); (2) glutamine; (3) palmitic acid; and (4) bioactive exosomal microRNAs, which in a synergistical fashion promote mTORC1-dependent translation. In all mammals except Neolithic humans, postnatal activation of mTORC1 by milk intake is restricted to the postnatal lactation period. It is of critical concern that persistent hyperactivation of mTORC1 is associated with aging and the development of age-related disorders such as obesity, type 2 diabetes mellitus, cancer, and neurodegenerative diseases. Persistent mTORC1 activation promotes endoplasmic reticulum (ER) stress and drives an aimless quasi-program, which promotes aging and age-related diseases. PMID:26225961

  6. PGE{sub 2}-induced colon cancer growth is mediated by mTORC1

    Energy Technology Data Exchange (ETDEWEB)

    Dufour, Marc, E-mail: Marc.dufour@chuv.ch; Faes, Seraina, E-mail: Seraina.faes@chuv.ch; Dormond-Meuwly, Anne, E-mail: Anne.meuwly-Dormond@chuv.ch; Demartines, Nicolas, E-mail: Demartines@chuv.ch; Dormond, Olivier, E-mail: Olivier.dormond@chuv.ch

    2014-09-05

    Highlights: • PGE{sub 2} activates mTORC1 in colon cancer cells. • Inhibition of mTORC1 blocks PGE{sub 2} induced colon cancer cell growth. • mTORC1 is a signaling intermediary in PGE{sub 2} induced colon cancer cell responses. - Abstract: The inflammatory prostaglandin E{sub 2} (PGE{sub 2}) cytokine plays a key role in the development of colon cancer. Several studies have shown that PGE{sub 2} directly induces the growth of colon cancer cells and furthermore promotes tumor angiogenesis by increasing the production of the vascular endothelial growth factor (VEGF). The signaling intermediaries implicated in these processes have however not been fully characterized. In this report, we show that the mechanistic target of rapamycin complex 1 (mTORC1) plays an important role in PGE{sub 2}-induced colon cancer cell responses. Indeed, stimulation of LS174T cells with PGE{sub 2} increased mTORC1 activity as observed by the augmentation of S6 ribosomal protein phosphorylation, a downstream effector of mTORC1. The PGE{sub 2} EP{sub 4} receptor was responsible for transducing the signal to mTORC1. Moreover, PGE{sub 2} increased colon cancer cell proliferation as well as the growth of colon cancer cell colonies grown in matrigel and blocking mTORC1 by rapamycin or ATP-competitive inhibitors of mTOR abrogated these effects. Similarly, the inhibition of mTORC1 by downregulation of its component raptor using RNA interference blocked PGE{sub 2}-induced LS174T cell growth. Finally, stimulation of LS174T cells with PGE{sub 2} increased VEGF production which was also prevented by mTORC1 inhibition. Taken together, these results show that mTORC1 is an important signaling intermediary in PGE{sub 2} mediated colon cancer cell growth and VEGF production. They further support a role for mTORC1 in inflammation induced tumor growth.

  7. mTORC1-Induced HK1-Dependent Glycolysis Regulates NLRP3 Inflammasome Activation.

    Science.gov (United States)

    Moon, Jong-Seok; Hisata, Shu; Park, Mi-Ae; DeNicola, Gina M; Ryter, Stefan W; Nakahira, Kiichi; Choi, Augustine M K

    2015-07-07

    The mammalian target of rapamycin complex 1 (mTORC1) regulates activation of immune cells and cellular energy metabolism. Although glycolysis has been linked to immune functions, the mechanisms by which glycolysis regulates NLRP3 inflammasome activation remain unclear. Here, we demonstrate that mTORC1-induced glycolysis provides an essential mechanism for NLRP3 inflammasome activation. Moreover, we demonstrate that hexokinase 1 (HK1)-dependent glycolysis, under the regulation of mTORC1, represents a critical metabolic pathway for NLRP3 inflammasome activation. Downregulation of glycolysis by inhibition of Raptor/mTORC1 or HK1 suppressed both pro-IL-1β maturation and caspase-1 activation in macrophages in response to LPS and ATP. These results suggest that upregulation of HK1-dependent glycolysis by mTORC1 regulates NLRP3 inflammasome activation. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  8. Amino Acids Regulate mTORC1 by an Obligate Two-step Mechanism*

    Science.gov (United States)

    Dyachok, Julia; Earnest, Svetlana; Iturraran, Erica N.; Cobb, Melanie H.

    2016-01-01

    The mechanistic target of rapamycin complex 1 (mTORC1) coordinates cell growth with its nutritional, hormonal, energy, and stress status. Amino acids are critical regulators of mTORC1 that permit other inputs to mTORC1 activity. However, the roles of individual amino acids and their interactions in mTORC1 activation are not well understood. Here we demonstrate that activation of mTORC1 by amino acids includes two discrete and separable steps: priming and activation. Sensitizing mTORC1 activation by priming amino acids is a prerequisite for subsequent stimulation of mTORC1 by activating amino acids. Priming is achieved by a group of amino acids that includes l-asparagine, l-glutamine, l-threonine, l-arginine, l-glycine, l-proline, l-serine, l-alanine, and l-glutamic acid. The group of activating amino acids is dominated by l-leucine but also includes l-methionine, l-isoleucine, and l-valine. l-Cysteine predominantly inhibits priming but not the activating step. Priming and activating steps differ in their requirements for amino acid concentration and duration of treatment. Priming and activating amino acids use mechanisms that are distinct both from each other and from growth factor signaling. Neither step requires intact tuberous sclerosis complex of proteins to activate mTORC1. Concerted action of priming and activating amino acids is required to localize mTORC1 to lysosomes and achieve its activation. PMID:27587390

  9. Raptor mediates the antiproliferation of cardamonin by mTORC1 inhibition in SKOV3 cells.

    Science.gov (United States)

    Shi, Daohua; Zhu, Yanting; Niu, Peiguang; Zhou, Jintuo; Chen, Huajiao

    2018-01-01

    Cardamonin inhibits the proliferation of SKOV3 cells by suppressing the mammalian target of rapamycin complex 1 (mTORC1). However, the mechanism of cardamonin on mTORC1 inhibition has not been well demonstrated. The regulatory-associated protein of TOR (Raptor) is an essential component of mTORC1. Here, we investigated the role of Raptor in the mTORC1 inhibition effect of cardamonin in SKOV3 cells. The expression of Raptor was knockdown by small interfering RNA (siRNA). The expressions of specific binding proteins of mTORC1 were analyzed by Western blotting, and the cell proliferation was detected by methyl thiazolyl tetrazolium (MTT) assay. Rapamycin, AZD8055, and cardamonin inhibited the activity of mammalian target of rapamycin (mTOR). Different from rapamycin and AZD8055, cardamonin suppressed the phosphorylation and protein expression of Raptor. Transfected with Raptor siRNA, the mTOR activation and proliferation of SKOV3 cells were decreased, and these effects were strengthened by cardamonin in Raptor siRNA SKOV3 cells. Cardamonin interfered with the lysosomal colocalization of mTOR with lysosomal associated membrane protein 2 (LAMP2), which was also hindered by Raptor siRNA. Furthermore, cardamonin strengthened the inhibitory effect on the lysosomal localization of mTOR in Raptor siRNA cells. Our results suggested that Raptor mainly mediated the inhibition of cardamonin on mTORC1 in SKOV3 cells.

  10. Deficiency in mTORC1-controlled C/EBP beta-mRNA translation improves metabolic health in mice

    NARCIS (Netherlands)

    Zidek, Laura M.; Ackermann, Tobias; Hartleben, Goetz; Eichwald, Sabrina; Kortman, Gertrud; Kiehntopf, Michael; Leutz, Achim; Sonenberg, Nahum; Wang, Zhao-Qi; von Maltzahn, Julia; Mueller, Christine; Calkhoven, Cornelis F.

    The mammalian target of rapamycin complex 1 (mTORC1) is a central regulator of physiological adaptations in response to changes in nutrient supply. Major downstream targets of mTORC1 signalling are the mRNA translation regulators p70 ribosomal protein S6 kinase 1 (S6K1p70) and the 4E-binding

  11. Lysosomal Regulation of mTORC1 by Amino Acids in Mammalian Cells

    Directory of Open Access Journals (Sweden)

    Yao Yao

    2017-07-01

    Full Text Available The mechanistic target of rapamycin complex 1 (mTORC1 is a master regulator of cell growth in eukaryotic cells. The active mTORC1 promotes cellular anabolic processes including protein, pyrimidine, and lipid biosynthesis, and inhibits catabolic processes such as autophagy. Consistent with its growth-promoting functions, hyper-activation of mTORC1 signaling is one of the important pathomechanisms underlying major human health problems including diabetes, neurodegenerative disorders, and cancer. The mTORC1 receives multiple upstream signals such as an abundance of amino acids and growth factors, thus it regulates a wide range of downstream events relevant to cell growth and proliferation control. The regulation of mTORC1 by amino acids is a fast-evolving field with its detailed mechanisms currently being revealed as the precise picture emerges. In this review, we summarize recent progress with respect to biochemical and biological findings in the regulation of mTORC1 signaling on the lysosomal membrane by amino acids.

  12. CXCL12-induced macropinocytosis modulates two distinct pathways to activate mTORC1 in macrophages.

    Science.gov (United States)

    Pacitto, Regina; Gaeta, Isabella; Swanson, Joel A; Yoshida, Sei

    2017-03-01

    Although growth factors and chemokines elicit different overall effects on cells-growth and chemotaxis, respectively-and activate distinct classes of cell-surface receptors, nonetheless, they trigger similar cellular activities and signaling pathways. The growth factor M-CSF and the chemokine CXCL12 both stimulate the endocytic process of macropinocytosis, and both activate the mechanistic target of rapamycin complex 1 (mTORC1), a protein complex that regulates cell metabolism. Recent studies of signaling by M-CSF in macrophages identified a role for macropinocytosis in the activation of mTORC1, in which delivery of extracellular amino acids into lysosomes via macropinocytosis was required for activation of mTORC1. Here, we analyzed the regulation of macropinosome (MP) formation in response to CXCL12 and identified 2 roles for macropinocytosis in the activation of mTORC1. Within 5 min of adding CXCL12, murine macrophages increased ruffling, macropinocytosis and amino acid-dependent activation of mTORC1. Inhibitors of macropinocytosis blocked activation of mTORC1, and various isoform-specific inhibitors of type 1 PI3K and protein kinase C (PKC) showed similar patterns of inhibition of macropinocytosis and mTORC1 activity. However, unlike the response to M-CSF, Akt phosphorylation (pAkt) in response to CXCL12 required the actin cytoskeleton and the formation of macropinocytic cups. Quantitative fluorescence microscopy showed that phosphatidylinositol (3,4,5)-trisphosphate (PIP 3 ), a product of PI3K and an upstream activator of Akt, localized to macropinocytic cups and that pAkt occurred primarily in cups. These results indicate that CXCL12 activates mTORC1 via 2 mechanisms: 1) that the macropinocytic cup localizes Akt signaling and 2) that MPs convey extracellular nutrients to lysosomes. © Society for Leukocyte Biology.

  13. Novel exosome-targeted T-cell-based vaccine counteracts T-cell anergy and converts CTL exhaustion in chronic infection via CD40L signaling through the mTORC1 pathway.

    Science.gov (United States)

    Wang, Rong; Xu, Aizhang; Zhang, Xueying; Wu, Jie; Freywald, Andrew; Xu, Jianqing; Xiang, Jim

    2017-06-01

    CD8 + cytotoxic T lymphocyte (CTL) exhaustion is a chief issue for ineffective virus elimination in chronic infectious diseases. We generated novel ovalbumin (OVA)-specific OVA-Texo and HIV-specific Gag-Texo vaccines inducing therapeutic immunity. To assess their therapeutic effect in chronic infection, we developed a new chronic infection model by i.v. infecting C57BL/6 mice with the OVA-expressing adenovirus AdVova. During chronic AdVova infection, mouse CTLs were found to express the inhibitory molecules programmed cell-death protein-1 (PD-1) and lymphocyte-activation gene-3 (LAG-3) and to be functionally exhausted, showing a significant deficiency in T-cell proliferation, IFN-γ production and cytolytic effects. Naive CD8 + T cells upregulated inhibitory PD-ligand 1 (PD-L1), B- and T-lymphocyte attenuator and T-cell anergy-associated molecules (Grail and Itch) while down-regulating the proliferative response upon stimulation in mice with chronic infection. Remarkably, the OVA-Texo vaccine counteracted T-cell anergy and converted CTL exhaustion. The latter was associated with (i) the upregulation of a marker for CTL functionality, diacetylated histone-H3 (diAcH3), (ii) a fourfold increase in CTLs, occurring independent of host DCs or CD4 + T cells, and (iii) the restoration of CTL IFN-γ production and cytotoxicity. In vivo OVA-Texo-stimulated CTLs upregulated the activities of the mTORC1 pathway-related molecules Akt, S6, eIF4E and T-bet, and treatment of the CTLs with an mTORC1 inhibitor, rapamycin, significantly reduced the OVA-Texo-induced increase in CTLs. Interestingly, OVA-Texo-mediated CD40L signaling played a critical role in the observed immunological effects. Importantly, the Gag-Texo vaccine induced Gag-specific therapeutic immunity in chronic infection. Therefore, this study should have a serious impact on the development of new therapeutic vaccines for human immunodeficiency virus (HIV-1) infection.

  14. Hepatic mTORC1 Opposes Impaired Insulin Action to Control Mitochondrial Metabolism in Obesity

    Directory of Open Access Journals (Sweden)

    Blanka Kucejova

    2016-07-01

    Full Text Available Dysregulated mitochondrial metabolism during hepatic insulin resistance may contribute to pathophysiologies ranging from elevated glucose production to hepatocellular oxidative stress and inflammation. Given that obesity impairs insulin action but paradoxically activates mTORC1, we tested whether insulin action and mammalian target of rapamycin complex 1 (mTORC1 contribute to altered in vivo hepatic mitochondrial metabolism. Loss of hepatic insulin action for 2 weeks caused increased gluconeogenesis, mitochondrial anaplerosis, tricarboxylic acid (TCA cycle oxidation, and ketogenesis. However, activation of mTORC1, induced by the loss of hepatic Tsc1, suppressed these fluxes. Only glycogen synthesis was impaired by both loss of insulin receptor and mTORC1 activation. Mice with a double knockout of the insulin receptor and Tsc1 had larger livers, hyperglycemia, severely impaired glycogen storage, and suppressed ketogenesis, as compared to those with loss of the liver insulin receptor alone. Thus, activation of hepatic mTORC1 opposes the catabolic effects of impaired insulin action under some nutritional states.

  15. Aspirin disrupts the mTOR-Raptor complex and potentiates the anti-cancer activities of sorafenib via mTORC1 inhibition.

    Science.gov (United States)

    Sun, Danni; Liu, Hongchun; Dai, Xiaoyang; Zheng, Xingling; Yan, Juan; Wei, Rongrui; Fu, Xuhong; Huang, Min; Shen, Aijun; Huang, Xun; Ding, Jian; Geng, Meiyu

    2017-10-10

    Aspirin is associated with a reduced risk of cancer and delayed progression of malignant disease. Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK)-mTOR signaling is believed to partially contribute to these anticancer effects, although the mechanism is unclear. In this study, we revealed the mechanism underlying the effects of aspirin on AMPK-mTOR signaling, and described a mechanism-based rationale for the use of aspirin in cancer therapy. We found that aspirin inhibited mTORC1 signaling through AMPK-dependent and -independent manners. Aspirin inhibited the AMPK-TSC pathway, thus resulting in the suppression of mTORC1 activity. In parallel, it directly disrupted the mTOR-raptor interaction. Additionally, the combination of aspirin and sorafenib showed synergetic effects via inhibiting mTORC1 signaling and the PI3K/AKT, MAPK/ERK pathways. Aspirin and sorafenib showed synergetic anticancer efficacy in the SMMC-7721 model. Our study provides mechanistic insights and a mechanism-based rationale for the roles of aspirin in cancer treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Impaired regeneration in calpain-3 null muscle is associated with perturbations in mTORC1 signaling and defective mitochondrial biogenesis.

    Science.gov (United States)

    Yalvac, Mehmet E; Amornvit, Jakkrit; Braganza, Cilwyn; Chen, Lei; Hussain, Syed-Rehan A; Shontz, Kimberly M; Montgomery, Chrystal L; Flanigan, Kevin M; Lewis, Sarah; Sahenk, Zarife

    2017-12-14

    Previous studies in patients with limb-girdle muscular dystrophy type 2A (LGMD2A) have suggested that calpain-3 (CAPN3) mutations result in aberrant regeneration in muscle. To gain insight into pathogenesis of aberrant muscle regeneration in LGMD2A, we used a paradigm of cardiotoxin (CTX)-induced cycles of muscle necrosis and regeneration in the CAPN3-KO mice to simulate the early features of the dystrophic process in LGMD2A. The temporal evolution of the regeneration process was followed by assessing the oxidative state, size, and the number of metabolic fiber types at 4 and 12 weeks after last CTX injection. Muscles isolated at these time points were further investigated for the key regulators of the pathways involved in various cellular processes such as protein synthesis, cellular energy status, metabolism, and cell stress to include Akt/mTORC1 signaling, mitochondrial biogenesis, and AMPK signaling. TGF-β and microRNA (miR-1, miR-206, miR-133a) regulation were also assessed. Additional studies included in vitro assays for quantifying fusion index of myoblasts from CAPN3-KO mice and development of an in vivo gene therapy paradigm for restoration of impaired regeneration using the adeno-associated virus vector carrying CAPN3 gene in the muscle. At 4 and 12 weeks after last CTX injection, we found impaired regeneration in CAPN3-KO muscle characterized by excessive numbers of small lobulated fibers belonging to oxidative metabolic type (slow twitch) and increased connective tissue. TGF-β transcription levels in the regenerating CAPN3-KO muscles were significantly increased along with microRNA dysregulation compared to wild type (WT), and the attenuated radial growth of muscle fibers was accompanied by perturbed Akt/mTORC1 signaling, uncoupled from protein synthesis, through activation of AMPK pathway, thought to be triggered by energy shortage in the CAPN3-KO muscle. This was associated with failure to increase mitochondria content, PGC-1α, and ATP5D

  17. mTORC1-Induced HK1-Dependent Glycolysis Regulates NLRP3 Inflammasome Activation

    Directory of Open Access Journals (Sweden)

    Jong-Seok Moon

    2015-07-01

    Full Text Available The mammalian target of rapamycin complex 1 (mTORC1 regulates activation of immune cells and cellular energy metabolism. Although glycolysis has been linked to immune functions, the mechanisms by which glycolysis regulates NLRP3 inflammasome activation remain unclear. Here, we demonstrate that mTORC1-induced glycolysis provides an essential mechanism for NLRP3 inflammasome activation. Moreover, we demonstrate that hexokinase 1 (HK1-dependent glycolysis, under the regulation of mTORC1, represents a critical metabolic pathway for NLRP3 inflammasome activation. Downregulation of glycolysis by inhibition of Raptor/mTORC1 or HK1 suppressed both pro-IL-1β maturation and caspase-1 activation in macrophages in response to LPS and ATP. These results suggest that upregulation of HK1-dependent glycolysis by mTORC1 regulates NLRP3 inflammasome activation.

  18. PDMP, a ceramide analogue, acts as an inhibitor of mTORC1 by inducing its translocation from lysosome to endoplasmic reticulum

    Energy Technology Data Exchange (ETDEWEB)

    Ode, Takashi [Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510 (Japan); Research Fellow of the Japan Society for the Promotion of Science (JSPS), 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-0083 (Japan); Podyma-Inoue, Katarzyna A.; Terasawa, Kazue [Department of Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510 (Japan); Inokuchi, Jin-ichi [Division of Glycopathology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, 4-4-1, Komatsushima, Aoba-ku, Sendai, Miyagi 981-8558 (Japan); Kobayashi, Toshihide [Lipid Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); CNRS, UMR 7213, University of Strasbourg, 67401 Illkirch (France); Watabe, Tetsuro [Department of Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510 (Japan); Izumi, Yuichi [Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510 (Japan); Hara-Yokoyama, Miki, E-mail: m.yokoyama.bch@tmd.ac.jp [Department of Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510 (Japan)

    2017-01-01

    Mammalian or mechanistic target of rapamycin complex 1 (mTORC1) is a master regulator of cell growth, metabolism, and cell differentiation. Recent studies have revealed that the recruitment of mTORC1 to lysosomes is essential for its activation. The ceramide analogue 1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP), a well known glycosphingolipid synthesis inhibitor, also affects the structures and functions of various organelles, including lysosomes and endoplasmic reticulum (ER). We investigated whether PDMP regulates the mTORC1 activity through its effects on organellar behavior. PDMP induced the translocation of mTORC1 from late endosomes/lysosomes, leading to the dissociation of mTORC1 from its activator Rheb in MC3T3-E1 cells. Surprisingly, we found mTORC1 translocation to the ER upon PDMP treatment. This effect of PDMP was independent of its action as the inhibitor, since two stereoisomers of PDMP, with and without the inhibitor activity, showed essentially the same effect. We confirmed that PDMP inhibits the mTORC1 activity based on the decrease in the phosphorylation of ribosomal S6 kinase, a downstream target of mTORC1, and the increase in LC3 puncta, reflecting autophagosome formation. Furthermore, PDMP inhibited the mTORC1-dependent osteoblastic cell proliferation and differentiation of MC3T3-E1 cells. Accordingly, the present results reveal a novel mechanism of PDMP, which inhibits the mTORC1 activity by inducing the translocation of mTOR from lysosomes to the ER. - Highlights: • The ceramide analogue, PDMP, suppressed the activation of mTORC1. • PDMP induced the translocation of mTOR from lysosomes to ER. • PDMP led to the dissociation of mTOR from its activator Rheb. • PDMP inhibited the mTORC1-dependent osteoblastic cell proliferation.

  19. mTORC1-Dependent Metabolic Reprogramming Underlies Escape from Glycolysis Addiction in Cancer Cells.

    Science.gov (United States)

    Pusapati, Raju V; Daemen, Anneleen; Wilson, Catherine; Sandoval, Wendy; Gao, Min; Haley, Benjamin; Baudy, Andreas R; Hatzivassiliou, Georgia; Evangelista, Marie; Settleman, Jeff

    2016-04-11

    Although glycolysis is substantially elevated in many tumors, therapeutic targeting of glycolysis in cancer patients has not yet been successful, potentially reflecting the metabolic plasticity of tumor cells. In various cancer cells exposed to a continuous glycolytic block, we identified a recurrent reprogramming mechanism involving sustained mTORC1 signaling that underlies escape from glycolytic addiction. Active mTORC1 directs increased glucose flux via the pentose phosphate pathway back into glycolysis, thereby circumventing a glycolysis block and ensuring adequate ATP and biomass production. Combined inhibition of glycolysis and mTORC1 signaling disrupted metabolic reprogramming in tumor cells and inhibited their growth in vitro and in vivo. These findings reveal novel combinatorial therapeutic strategies to realize the potential benefit from targeting the Warburg effect. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Disruption of the Rag-Ragulator Complex by c17orf59 Inhibits mTORC1

    Directory of Open Access Journals (Sweden)

    Lawrence D. Schweitzer

    2015-09-01

    Full Text Available mTORC1 controls key processes that regulate cell growth, including mRNA translation, ribosome biogenesis, and autophagy. Environmental amino acids activate mTORC1 by promoting its recruitment to the cytosolic surface of the lysosome, where its kinase is activated downstream of growth factor signaling. mTORC1 is brought to the lysosome by the Rag GTPases, which are tethered to the lysosomal membrane by Ragulator, a lysosome-bound scaffold. Here, we identify c17orf59 as a Ragulator-interacting protein that regulates mTORC1 activity through its interaction with Ragulator at the lysosome. The binding of c17orf59 to Ragulator prevents Ragulator interaction with the Rag GTPases, both in cells and in vitro, and decreases Rag GTPase lysosomal localization. Disruption of the Rag-Ragulator interaction by c17orf59 impairs mTORC1 activation by amino acids by preventing mTOR from reaching the lysosome. By disrupting the Rag-Ragulator interaction to inhibit mTORC1, c17orf59 expression may represent another mechanism to modulate nutrient sensing by mTORC1.

  1. The mTORC1 pathway stimulates glutamine metabolism and cell proliferation by repressing SIRT4

    Science.gov (United States)

    Csibi, Alfred; Fendt, Sarah-Maria; Li, Chenggang; Poulogiannis, George; Choo, Andrew Y.; Chapski, Douglas J.; Jeong, Seung Min; Dempsey, Jamie; Parkhitko, Andrey; Morrison, Tasha; Henske, Elizabeth; Haigis, Marcia; Cantley, Lewis C.; Stephanopoulos, Gregory; Yu, Jane; Blenis, John

    2013-01-01

    Summary Proliferating mammalian cells use glutamine as a source of nitrogen and as a key anaplerotic source to provide metabolites to the tricarboxylic acid cycle (TCA) for biosynthesis. Recently, mTORC1 activation has been correlated with increased nutrient uptake and metabolism, but no molecular connection to glutaminolysis has been reported. Here, we show that mTORC1 promotes glutamine anaplerosis by activating glutamate dehydrogenase (GDH). This regulation requires transcriptional repression of SIRT4, the mitochondrial-localized sirtuin that inhibits GDH. Mechanistically, mTORC1 represses SIRT4 by promoting the proteasome-mediated destabilization of cAMP response element binding-2 (CREB2). Thus, a relationship between mTORC1, SIRT4 and cancer is suggested by our findings. Indeed, SIRT4 expression is reduced in human cancer, and its overexpression reduces cell proliferation, transformation and tumor development. Finally, our data indicate that targeting nutrient metabolism in energy-addicted cancers with high mTORC1 signaling may be an effective therapeutic approach. PMID:23663782

  2. mTORC1 inhibition delays growth of neurofibromatosis type 2 schwannoma

    Science.gov (United States)

    Giovannini, Marco; Bonne, Nicolas-Xavier; Vitte, Jeremie; Chareyre, Fabrice; Tanaka, Karo; Adams, Rocky; Fisher, Laurel M.; Valeyrie-Allanore, Laurence; Wolkenstein, Pierre; Goutagny, Stephane; Kalamarides, Michel

    2014-01-01

    Background Neurofibromatosis type 2 (NF2) is a rare autosomal dominant genetic disorder, resulting in a variety of neural tumors, with bilateral vestibular schwannomas as the most frequent manifestation. Recently, merlin, the NF2 tumor suppressor, has been identified as a novel negative regulator of mammalian target of rapamycin complex 1 (mTORC1); functional loss of merlin was shown to result in elevated mTORC1 signaling in NF2-related tumors. Thus, mTORC1 pathway inhibition may be a useful targeted therapeutic approach. Methods We studied in vitro cell models, cohorts of mice allografted with Nf2−/− Schwann cells, and a genetically modified mouse model of NF2 schwannoma in order to evaluate the efficacy of the proposed targeted therapy for NF2. Results We found that treatment with the mTORC1 inhibitor rapamycin reduced the severity of NF2-related Schwann cell tumorigenesis without significant toxicity. Consistent with these results, in an NF2 patient with growing vestibular schwannomas, the rapalog sirolimus induced tumor growth arrest. Conclusions Taken together, these results constitute definitive evidence that justifies proceeding with clinical trials using mTORC1-targeted agents in selected patients with NF2 and in patients with NF2-related sporadic tumors. PMID:24414536

  3. Macrophage mTORC1 disruption reduces inflammation and insulin resistance in obese mice

    NARCIS (Netherlands)

    Jiang, Hongfeng; Westerterp, Marit; Wang, Chunjiong; Zhu, Yi; Ai, Ding

    2014-01-01

    Inflammatory factors secreted by macrophages play an important role in obesity-related insulin resistance. Being at the crossroads of a nutrient-hormonal signalling network, the mammalian target of rapamycin complex 1 (mTORC1) controls important functions in the regulation of energy balance and

  4. Disruption of the vacuolar-type H+-ATPase complex in liver causes MTORC1-independent accumulation of autophagic vacuoles and lysosomes.

    Science.gov (United States)

    Kissing, Sandra; Rudnik, Sönke; Damme, Markus; Lüllmann-Rauch, Renate; Ichihara, Atsuhiro; Kornak, Uwe; Eskelinen, Eeva-Liisa; Jabs, Sabrina; Heeren, Jörg; De Brabander, Jef K; Haas, Albert; Saftig, Paul

    2017-04-03

    The vacuolar-type H + -translocating ATPase (v-H + -ATPase) has been implicated in the amino acid-dependent activation of the mechanistic target of rapamycin complex 1 (MTORC1), an important regulator of macroautophagy. To reveal the mechanistic links between the v-H + -ATPase and MTORC1, we destablilized v-H + -ATPase complexes in mouse liver cells by induced deletion of the essential chaperone ATP6AP2. ATP6AP2-mutants are characterized by massive accumulation of endocytic and autophagic vacuoles in hepatocytes. This cellular phenotype was not caused by a block in endocytic maturation or an impaired acidification. However, the degradation of LC3-II in the knockout hepatocytes appeared to be reduced. When v-H + -ATPase levels were decreased, we observed lysosome association of MTOR and normal signaling of MTORC1 despite an increase in autophagic marker proteins. To better understand why MTORC1 can be active when v-H + -ATPase is depleted, the activation of MTORC1 was analyzed in ATP6AP2-deficient fibroblasts. In these cells, very little amino acid-elicited activation of MTORC1 was observed. In contrast, insulin did induce MTORC1 activation, which still required intracellular amino acid stores. These results suggest that in vivo the regulation of macroautophagy depends not only on v-H + -ATPase-mediated regulation of MTORC1.

  5. REDD1/DDIT4-independent mTORC1 inhibition and apoptosis by glucocorticoids in thymocytes.

    Science.gov (United States)

    Wolff, Nicholas C; McKay, Renée M; Brugarolas, James

    2014-06-01

    Glucocorticoids induce apoptosis in lymphocytes and are commonly used to treat hematologic malignancies. However, they are also associated with significant adverse effects and their molecular mechanism of action is not fully understood. Glucocorticoid treatment induces expression of the mTORC1 inhibitor Regulated in Development and DNA Damage Response 1 (REDD1), also known as DNA-Damage Inducible Transcript 4 (DDIT4), and mTORC1 inhibition may distinguish glucocorticoid-sensitive from glucocorticoid-resistant acute lymphoblastic leukemia (ALL). Interestingly, REDD1 induction was impaired in glucocorticoid-resistant ALL cells and inhibition of mTORC1 using rapamycin restored glucocorticoid sensitivity. These data suggest that REDD1 may be essential for the response of ALL cells to glucocorticoids. To further investigate the role of REDD1, we evaluated the effects of glucocorticoids on primary thymocytes from wild-type and REDD1-deficient mice. Glucocorticoid-mediated apoptosis was blocked by a glucocorticoid receptor antagonist and by an inhibitor of transcription, which interfered with REDD1 induction and mTORC1 inhibition. However, REDD1 ablation had no effect on glucocorticoid-induced mTORC1 inhibition and apoptosis in thymocytes ex vivo. Overall, these data not only demonstrate the contextual differences of downstream signaling following glucocorticoid treatment but also provide a better mechanistic understanding of the role of REDD1. These molecular findings underlying glucocorticoid action and the role of REDD1 are fundamental for the design of novel, more efficacious, and less toxic analogs. Mol Cancer Res; 12(6); 867-77. ©2014 AACR. ©2014 American Association for Cancer Research.

  6. The First Alcohol Drink Triggers mTORC1-Dependent Synaptic Plasticity in Nucleus Accumbens Dopamine D1 Receptor Neurons.

    Science.gov (United States)

    Beckley, Jacob T; Laguesse, Sophie; Phamluong, Khanhky; Morisot, Nadege; Wegner, Scott A; Ron, Dorit

    2016-01-20

    , which is dependent on D1R and mTORC1. We also find that mTORC1 is necessary for the sustained alcohol consumption and preference across the initial drinking sessions. The first alcohol binge activates mTORC1 in NAc D1+ neurons and increases levels of synaptic proteins involved in glutamatergic signaling. Thus, the D1R/mTORC1-dependent plasticity following the first alcohol exposure may be a critical cellular component of reinforcement learning. Copyright © 2016 the authors 0270-6474/16/360701-13$15.00/0.

  7. SMG-1 and mTORC1 act antagonistically to regulate response to injury and growth in planarians.

    Directory of Open Access Journals (Sweden)

    Cristina González-Estévez

    Full Text Available Planarian flatworms are able to both regenerate their whole bodies and continuously adapt their size to nutrient status. Tight control of stem cell proliferation and differentiation during these processes is the key feature of planarian biology. Here we show that the planarian homolog of the phosphoinositide 3-kinase-related kinase (PIKK family member SMG-1 and mTOR complex 1 components are required for this tight control. Loss of smg-1 results in a hyper-responsiveness to injury and growth and the formation of regenerative blastemas that remain undifferentiated and that lead to lethal ectopic outgrowths. Invasive stem cell hyper-proliferation, hyperplasia, hypertrophy, and differentiation defects are hallmarks of this uncontrolled growth. These data imply a previously unappreciated and novel physiological function for this PIKK family member. In contrast we found that planarian members of the mTOR complex 1, tor and raptor, are required for the initial response to injury and blastema formation. Double smg-1 RNAi experiments with tor or raptor show that abnormal growth requires mTOR signalling. We also found that the macrolide rapamycin, a natural compound inhibitor of mTORC1, is able to increase the survival rate of smg-1 RNAi animals by decreasing cell proliferation. Our findings support a model where Smg-1 acts as a novel regulator of both the response to injury and growth control mechanisms. Our data suggest the possibility that this may be by suppressing mTOR signalling. Characterisation of both the planarian mTORC1 signalling components and another PIKK family member as key regulators of regeneration and growth will influence future work on regeneration, growth control, and the development of anti-cancer therapies that target mTOR signalling.

  8. SMG-1 and mTORC1 Act Antagonistically to Regulate Response to Injury and Growth in Planarians

    Science.gov (United States)

    González-Estévez, Cristina; Felix, Daniel A.; Smith, Matthew D.; Paps, Jordi; Morley, Simon J.; James, Victoria; Sharp, Tyson V.; Aboobaker, A. Aziz

    2012-01-01

    Planarian flatworms are able to both regenerate their whole bodies and continuously adapt their size to nutrient status. Tight control of stem cell proliferation and differentiation during these processes is the key feature of planarian biology. Here we show that the planarian homolog of the phosphoinositide 3-kinase-related kinase (PIKK) family member SMG-1 and mTOR complex 1 components are required for this tight control. Loss of smg-1 results in a hyper-responsiveness to injury and growth and the formation of regenerative blastemas that remain undifferentiated and that lead to lethal ectopic outgrowths. Invasive stem cell hyper-proliferation, hyperplasia, hypertrophy, and differentiation defects are hallmarks of this uncontrolled growth. These data imply a previously unappreciated and novel physiological function for this PIKK family member. In contrast we found that planarian members of the mTOR complex 1, tor and raptor, are required for the initial response to injury and blastema formation. Double smg-1 RNAi experiments with tor or raptor show that abnormal growth requires mTOR signalling. We also found that the macrolide rapamycin, a natural compound inhibitor of mTORC1, is able to increase the survival rate of smg-1 RNAi animals by decreasing cell proliferation. Our findings support a model where Smg-1 acts as a novel regulator of both the response to injury and growth control mechanisms. Our data suggest the possibility that this may be by suppressing mTOR signalling. Characterisation of both the planarian mTORC1 signalling components and another PIKK family member as key regulators of regeneration and growth will influence future work on regeneration, growth control, and the development of anti-cancer therapies that target mTOR signalling. PMID:22479207

  9. Milk—A Nutrient System of Mammalian Evolution Promoting mTORC1-Dependent Translation

    OpenAIRE

    Bodo C. Melnik

    2015-01-01

    Based on own translational research of the biochemical and hormonal effects of cow’s milk consumption in humans, this review presents milk as a signaling system of mammalian evolution that activates the nutrient-sensitive kinase mechanistic target of rapamycin complex 1 (mTORC1), the pivotal regulator of translation. Milk, a mammary gland-derived secretory product, is required for species-specific gene-nutrient interactions that promote appropriate growth and development of the newborn mammal...

  10. Regulation of hepatic LDL receptors by mTORC1 and PCSK9 in mice

    Science.gov (United States)

    Ai, Ding; Chen, Chiyuan; Han, Seongah; Ganda, Anjali; Murphy, Andrew J.; Haeusler, Rebecca; Thorp, Edward; Accili, Domenico; Horton, Jay D.; Tall, Alan R.

    2012-01-01

    Individuals with type 2 diabetes have an increased risk of atherosclerosis. One factor underlying this is dyslipidemia, which in hyperinsulinemic subjects with early type 2 diabetes is typically characterized by increased VLDL secretion but normal LDL cholesterol levels, possibly reflecting enhanced catabolism of LDL via hepatic LDLRs. Recent studies have also suggested that hepatic insulin signaling sustains LDLR levels. We therefore sought to elucidate the mechanisms linking hepatic insulin signaling to regulation of LDLR levels. In WT mice, insulin receptor knockdown by shRNA resulted in decreased hepatic mTORC1 signaling and LDLR protein levels. It also led to increased expression of PCSK9, a known post-transcriptional regulator of LDLR expression. Administration of the mTORC1 inhibitor rapamycin caused increased expression of PCSK9, decreased levels of hepatic LDLR protein, and increased levels of VLDL/LDL cholesterol in WT but not Pcsk9–/– mice. Conversely, mice with increased hepatic mTORC1 activity exhibited decreased expression of PCSK9 and increased levels of hepatic LDLR protein levels. Pcsk9 is regulated by the transcription factor HNF1α, and our further detailed analyses suggest that increased mTORC1 activity leads to activation of PKCδ, reduced activity of HNF4α and HNF1α, decreased PCSK9 expression, and ultimately increased hepatic LDLR protein levels, which result in decreased circulating LDL levels. We therefore suggest that PCSK9 inhibition could be an effective way to reduce the adverse side effect of increased LDL levels that is observed in transplant patients taking rapamycin as immunosuppressive therapy. PMID:22426206

  11. Amino acids regulate hepatic intermediary metabolism-related gene expression via mTORC1-dependent manner in rainbow trout (Oncorhynchus mykiss)

    OpenAIRE

    Dai, Wei Wei

    2015-01-01

    During my doctoral study, we used rainbow trout, a representative carnivorous fish and relevant diabetic model, to study the mechanisms underlying the regulation of hepatic intermediary metabolism by nutrients (amino acids (AAs) and glucose), and determine the potential involvement of insulin/Akt and mTORC1 signaling pathways in these regulations. Using acute administration of rapamycin, a pharmacological inhibitor of TOR, we first identified that mTORC1 activation promotes the expression of ...

  12. Rheb localized on the Golgi membrane activates lysosome-localized mTORC1 at the Golgi-lysosome contact site.

    Science.gov (United States)

    Hao, Feike; Kondo, Kazuhiko; Itoh, Takashi; Ikari, Sumiko; Nada, Shigeyuki; Okada, Masato; Noda, Takeshi

    2018-01-29

    In response to amino acid supply, mTORC1, a master regulator of cell growth, is recruited to the lysosome and activated by the small GTPase Rheb. However, the intracellular localization of Rheb is controversial. In this study, we showed that a significant portion of Rheb is localized on the Golgi but not on the lysosome. GFP-Rheb could activate mTORC1, even when forced to exclusively localize to the Golgi. Likewise, artificial recruitment of mTORC1 to the Golgi allowed its activation. Accordingly, the Golgi was in contact with the lysosome at an newly discovered area of the cell that we term the Golgi-lysosome contact site (GLCS). The number of GLCSs increased in response to amino acid supply, whereas GLCS perturbation suppressed mTORC1 activation. These results suggest that inter-organelle communication between the Golgi and lysosome is important for mTORC1 regulation and the Golgi-localized Rheb may activate mTORC1 at GLCSs. © 2018. Published by The Company of Biologists Ltd.

  13. Direct Hepatocyte Insulin Signaling Is Required for Lipogenesis but Is Dispensable for the Suppression of Glucose Production.

    Science.gov (United States)

    Titchenell, Paul M; Quinn, William J; Lu, Mingjian; Chu, Qingwei; Lu, Wenyun; Li, Changhong; Chen, Helen; Monks, Bobby R; Chen, Julia; Rabinowitz, Joshua D; Birnbaum, Morris J

    2016-06-14

    During insulin-resistant states such as type II diabetes mellitus (T2DM), insulin fails to suppress hepatic glucose production (HGP) yet promotes lipid synthesis. This metabolic state has been termed "selective insulin resistance" to indicate a defect in one arm of the insulin-signaling cascade, potentially downstream of Akt. Here we demonstrate that Akt-dependent activation of mTORC1 and inhibition of Foxo1 are required and sufficient for de novo lipogenesis, suggesting that hepatic insulin signaling is likely to be intact in insulin-resistant states. Moreover, cell-nonautonomous suppression of HGP by insulin depends on a reduction of adipocyte lipolysis and serum FFAs but is independent of vagal efferents or glucagon signaling. These data are consistent with a model in which, during T2DM, intact liver insulin signaling drives enhanced lipogenesis while excess circulating FFAs become a dominant inducer of nonsuppressible HGP. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. mTORC1 Inhibition Corrects Neurodevelopmental and Synaptic Alterations in a Human Stem Cell Model of Tuberous Sclerosis

    Directory of Open Access Journals (Sweden)

    Veronica Costa

    2016-04-01

    Full Text Available Hyperfunction of the mTORC1 pathway has been associated with idiopathic and syndromic forms of autism spectrum disorder (ASD, including tuberous sclerosis, caused by loss of either TSC1 or TSC2. It remains largely unknown how developmental processes and biochemical signaling affected by mTORC1 dysregulation contribute to human neuronal dysfunction. Here, we have characterized multiple stages of neurogenesis and synapse formation in human neurons derived from TSC2-deleted pluripotent stem cells. Homozygous TSC2 deletion causes severe developmental abnormalities that recapitulate pathological hallmarks of cortical malformations in patients. Both TSC2+/− and TSC2−/− neurons display altered synaptic transmission paralleled by molecular changes in pathways associated with autism, suggesting the convergence of pathological mechanisms in ASD. Pharmacological inhibition of mTORC1 corrects developmental abnormalities and synaptic dysfunction during independent developmental stages. Our results uncouple stage-specific roles of mTORC1 in human neuronal development and contribute to a better understanding of the onset of neuronal pathophysiology in tuberous sclerosis.

  15. mTORC1 promotes denervation-induced muscle atrophy through a mechanism involving the activation of FoxO and E3 ubiquitin ligases.

    Science.gov (United States)

    Tang, Huibin; Inoki, Ken; Lee, Myung; Wright, Erika; Khuong, Andy; Khuong, Amanda; Sugiarto, Sista; Garner, Matthew; Paik, Jihye; DePinho, Ronald A; Goldman, Daniel; Guan, Kun-Liang; Shrager, Joseph B

    2014-02-25

    Skeletal muscle mass and function are regulated by motor innervation, and denervation results in muscle atrophy. The activity of mammalian target of rapamycin complex 1 (mTORC1) is substantially increased in denervated muscle, but its regulatory role in denervation-induced atrophy remains unclear. At early stages after denervation of skeletal muscle, a pathway involving class II histone deacetylases and the transcription factor myogenin mediates denervation-induced muscle atrophy. We found that at later stages after denervation of fast-twitch muscle, activation of mTORC1 contributed to atrophy and that denervation-induced atrophy was mitigated by inhibition of mTORC1 with rapamycin. Activation of mTORC1 through genetic deletion of its inhibitor TSC1 (tuberous sclerosis complex 1) sensitized mice to denervation-induced muscle atrophy and suppressed the kinase activity of Akt, leading to activation of FoxO transcription factors and increasing the expression of genes encoding E3 ubiquitin ligases atrogin [also known as MAFbx (muscle atrophy F-box protein)] and MuRF1 (muscle-specific ring finger 1). Rapamycin treatment of mice restored Akt activity, suggesting that the denervation-induced increase in mTORC1 activity was producing feedback inhibition of Akt. Genetic deletion of the three FoxO isoforms in skeletal muscle induced muscle hypertrophy and abolished the late-stage induction of E3 ubiquitin ligases after denervation, thereby preventing denervation-induced atrophy. These data revealed that mTORC1, which is generally considered to be an important component of anabolism, is central to muscle catabolism and atrophy after denervation. This mTORC1-FoxO axis represents a potential therapeutic target in neurogenic muscle atrophy.

  16. Noncanonical Pathway for Regulation of CCL2 Expression by an mTORC1-FOXK1 Axis Promotes Recruitment of Tumor-Associated Macrophages

    Directory of Open Access Journals (Sweden)

    Hirokazu Nakatsumi

    2017-11-01

    Full Text Available C-C chemokine ligand 2 (CCL2 plays pivotal roles in tumor formation, progression, and metastasis. Although CCL2 expression has been found to be dependent on the nuclear factor (NF-κB signaling pathway, the regulation of CCL2 production in tumor cells has remained unclear. We have identified a noncanonical pathway for regulation of CCL2 production that is mediated by mammalian target of rapamycin complex 1 (mTORC1 but independent of NF-κB. Multiple phosphoproteomics approaches identified the transcription factor forkhead box K1 (FOXK1 as a downstream target of mTORC1. Activation of mTORC1 induces dephosphorylation of FOXK1, resulting in transactivation of the CCL2 gene. Inhibition of the mTORC1-FOXK1 axis attenuated insulin-induced CCL2 production as well as the accumulation of tumor-associated monocytes-macrophages and tumor progression in mice. Our results suggest that FOXK1 directly links mTORC1 signaling and CCL2 expression in a manner independent of NF-κB and that CCL2 produced by this pathway contributes to tumor progression.

  17. C6 ceramide sensitizes the anti-hepatocellular carcinoma (HCC) activity by AZD-8055, a novel mTORC1/2 dual inhibitor.

    Science.gov (United States)

    Liu, Mo; Gu, Peng; Guo, Wenjia; Fan, Xiwen

    2016-08-01

    Aberrant activation of mammalian target of rapamycin (mTOR) plays pivotal roles in promoting hepatocellular carcinoma (HCC) tumorigenesis and chemoresistance. Here, we tested the potential anti-HCC activity by a novel mTOR complex 1/2 (mTORC1/2) dual inhibitor AZD-8055 and, more importantly, the potential AZD-8055 sensitization effect by a cell-permeable short-chain ceramide (C6). We showed that AZD-8055 mainly exerted moderate cytotoxic effect against a panel of HCC cell lines (HepG2, Hep3B, and SMMC-7721). Co-treatment of C6 ceramide remarkably augmented AZD-8055-induced HCC cytotoxicity. Meanwhile, C6 ceramide dramatically potentiated AZD-8055-induced HCC cell apoptotic death. Further studies demonstrated that AZD-8055 and C6 ceramide synergistically induced anti-survival and pro-apoptotic activity in primary cultured human HCC cells, but not in the non-cancerous human hepatocytes. Signaling studies showed that AZD-8055 and C6 ceramide synergistically suppressed Akt-mTOR complex 1/2 cascade activation. In vivo, AZD-8055 oral administration suppressed HepG2 hepatoma xenograft growth in nude mice, while moderately improving mice survival. Its anti-tumor activity was dramatically potentiated with co-administration of a liposome-packed C6 ceramide. Together, these results demonstrate that concurrent targeting mTORC1/2 by AZD-8055 exerts anti-tumor ability in preclinical HCC models, and its activity is further sensitized with co-administration of C6 ceramide.

  18. Regulation of mitochondrial biogenesis in erythropoiesis by mTORC1-mediated protein translation.

    Science.gov (United States)

    Liu, Xin; Zhang, Yuannyu; Ni, Min; Cao, Hui; Signer, Robert A J; Li, Dan; Li, Mushan; Gu, Zhimin; Hu, Zeping; Dickerson, Kathryn E; Weinberg, Samuel E; Chandel, Navdeep S; DeBerardinis, Ralph J; Zhou, Feng; Shao, Zhen; Xu, Jian

    2017-06-01

    Advances in genomic profiling present new challenges of explaining how changes in DNA and RNA are translated into proteins linking genotype to phenotype. Here we compare the genome-scale proteomic and transcriptomic changes in human primary haematopoietic stem/progenitor cells and erythroid progenitors, and uncover pathways related to mitochondrial biogenesis enhanced through post-transcriptional regulation. Mitochondrial factors including TFAM and PHB2 are selectively regulated through protein translation during erythroid specification. Depletion of TFAM in erythroid cells alters intracellular metabolism, leading to elevated histone acetylation, deregulated gene expression, and defective mitochondria and erythropoiesis. Mechanistically, mTORC1 signalling is enhanced to promote translation of mitochondria-associated transcripts through TOP-like motifs. Genetic and pharmacological perturbation of mitochondria or mTORC1 specifically impairs erythropoiesis in vitro and in vivo. Our studies support a mechanism for post-transcriptional control of erythroid mitochondria and may have direct relevance to haematologic defects associated with mitochondrial diseases and ageing.

  19. Background Suppression Effects on Signal Estimation

    Energy Technology Data Exchange (ETDEWEB)

    Burr, Tom [Los Alamos National Laboratory

    2008-01-01

    Gamma detectors at border crossings are intended to detect illicit nuclear material. One performance challenge involves the fact that vehicles suppress the natural background, thus potentially reducing detection probability for threat items. Methods to adjust for background suppression have been considered in related but different settings. Here, methods to adjust for background suppression are tested in the context of signal estimation. Adjustment methods include several clustering options. We find that for the small-to-moderate suppression magnitudes exhibited in the analyzed data, suppression adjustment is only moderatel helpful in locating the signal peak, and in estimating its width or magnitude.

  20. mTORC1 activity repression by late endosomal phosphatidylinositol 3,4-bisphosphate.

    Science.gov (United States)

    Marat, Andrea L; Wallroth, Alexander; Lo, Wen-Ting; Müller, Rainer; Norata, Giuseppe Danilo; Falasca, Marco; Schultz, Carsten; Haucke, Volker

    2017-06-02

    Nutrient sensing by mechanistic target of rapamycin complex 1 (mTORC1) on lysosomes and late endosomes (LyLEs) regulates cell growth. Many factors stimulate mTORC1 activity, including the production of phosphatidylinositol 3,4,5-trisphosphate [PI(3,4,5)P 3 ] by class I phosphatidylinositol 3-kinases (PI3Ks) at the plasma membrane. We investigated mechanisms that repress mTORC1 under conditions of growth factor deprivation. We identified phosphatidylinositol 3,4-bisphosphate [PI(3,4)P 2 ], synthesized by class II PI3K β (PI3KC2β) at LyLEs, as a negative regulator of mTORC1, whereas loss of PI3KC2β hyperactivated mTORC1. Growth factor deprivation induced the association of PI3KC2β with the Raptor subunit of mTORC1. Local PI(3,4)P 2 synthesis triggered repression of mTORC1 activity through association of Raptor with inhibitory 14-3-3 proteins. These results unravel an unexpected function for local PI(3,4)P 2 production in shutting off mTORC1. Copyright © 2017, American Association for the Advancement of Science.

  1. Arctigenin exerts anti-colitis efficacy through inhibiting the differentiation of Th1 and Th17 cells via an mTORC1-dependent pathway.

    Science.gov (United States)

    Wu, Xin; Dou, Yannong; Yang, Yan; Bian, Difei; Luo, Jinque; Tong, Bei; Xia, Yufeng; Dai, Yue

    2015-08-15

    Arctigenin, the main effective constituent of Arctium lappa L. fruit, has previously been proven to dramatically attenuate dextran sulfate sodium (DSS)-induced colitis in mice, a frequently used animal model of inflammatory bowel disease (IBD). As Th1 and Th17 cells play a crucial role in the pathogenesis of IBD, the present study addressed whether and how arctigenin exerted anti-colitis efficacy by interfering with the differentiation and activation of Th1/Th17 cells. In vitro, arctigenin was shown to markedly inhibit the differentiation of Th17 cells from naïve T cells, and moderately inhibit the differentiation of Th1 cells, which was accompanied by lowered phosphorylation of STAT3 and STAT4, respectively. In contrast, arctigenin was lack of marked effect on the differentiation of either Th2 or regulatory T cells. Furthermore, arctigenin was shown to suppress the mammalian target of rapamycin complex 1 (mTORC1) pathway in T cells as demonstrated by down-regulated phosphorylation of the downstream target genes p70S6K and RPS6, and it functioned independent of two well-known upstream kinases PI3K/AKT and ERK. Arctigenin was also able to inhibit the activity of mTORC1 by dissociating raptor from mTOR. Interestingly, the inhibitory effect of arctigenin on T cell differentiation disappeared under a status of mTORC1 overactivation via knockdown of tuberous sclerosis complex 2 (TSC2, a negative regulator of mTORC1) or pretreatment of leucine (an agonist of mTOR). In DSS-induced mice, the inhibition of Th1/Th17 responses and anti-colitis effect of arctigenin were abrogated by leucine treatment. In conclusion, arctigenin ameliorates colitis through down-regulating the differentiation of Th1 and Th17 cells via mTORC1 pathway. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. GSK-3 directly regulates phospho-4EBP1 in renal cell carcinoma cell-line: an intrinsic subcellular mechanism for resistance to mTORC1 inhibition

    International Nuclear Information System (INIS)

    Ito, Hiromi; Ichiyanagi, Osamu; Naito, Sei; Bilim, Vladimir N.; Tomita, Yoshihiko; Kato, Tomoyuki; Nagaoka, Akira; Tsuchiya, Norihiko

    2016-01-01

    The phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin 1 (mTORC1) signaling pathway is aberrantly activated in renal cell carcinoma (RCC). We previously demonstrated glycogen synthase kinase-3β (GSK-3β) positively regulated RCC proliferation. The aim of this study was to evaluate the role of GSK-3 in the PI3K/Akt/mTORC1 pathway and regulation of the downstream substrates, eukaryotic translation initiation factor 4E-binding protein 1 (4EBP1), ribosomal protein S6 kinase (S6K), and ribosomal protein S6 (S6RP). We used human RCC cell lines (ACHN, Caki1, and A498) and, as normal controls, human renal proximal tubular epithelial cell (HRPTEpC) and non-tumorous kidney tissues that were obtained surgically for treatment of RCC patients. Rapamycin-resistant ACHN (ACHN/RR) cells were generated with chronic exposure of ACHN to rapamycin ranging from 1nM finally to 1 μM. Cell viability, cell cycling and direct interaction between GSK-3β and 4EBP1 were evaluated with MTS assay, flowcytometry and in vitro kinase assay with recombinant GSK-3β and 4EBP1products, respectively. Protein expression and phosphorylation of molecules associated with the PI3K/Akt/mTORC1 pathway were examined by immunoblotting. Effects of drug combination were determined as the combination index with CompuSyn software. Overexpression and phosphorylation of 4EBP1 and S6RP together with GSK-3 activation were observed in RCC cell lines, but not in human normal kidney cells and tissues. Cell proliferation, p4EBP1 and pS6RP were strongly suppressed by GSK-3 inhibition. Rapamycin and LY294002 sufficiently decreased pS6RP, but only moderately p4EBP1. In vitro kinase assays showed that recombinant GSK-3β phosphorylated recombinant 4EBP1, and the effect was blocked by GSK-3 inhibitors. Different from rapamycin, AR- A014418 remarkably inhibited cell proliferation, and rapidly suppressed p4EBP1 and pS6RP in ACHN and ACHN/RR (in 30 min to 1 h). AR- A014418 and rapamycin combination showed

  3. Acidic tumor microenvironment abrogates the efficacy of mTORC1 inhibitors.

    Science.gov (United States)

    Faes, Seraina; Duval, Adrian P; Planche, Anne; Uldry, Emilie; Santoro, Tania; Pythoud, Catherine; Stehle, Jean-Christophe; Horlbeck, Janine; Letovanec, Igor; Riggi, Nicolo; Demartines, Nicolas; Dormond, Olivier

    2016-12-05

    Blocking the mechanistic target of rapamycin complex-1 (mTORC1) with chemical inhibitors such as rapamycin has shown limited clinical efficacy in cancer. The tumor microenvironment is characterized by an acidic pH which interferes with cancer therapies. The consequences of acidity on the anti-cancer efficacy of mTORC1 inhibitors have not been characterized and are thus the focus of our study. Cancer cell lines were treated with rapamycin in acidic or physiological conditions and cell proliferation was investigated. The effect of acidity on mTORC1 activity was determined by Western blot. The anticancer efficacy of rapamycin in combination with sodium bicarbonate to increase the intratumoral pH was tested in two different mouse models and compared to rapamycin treatment alone. Histological analysis was performed on tumor samples to evaluate proliferation, apoptosis and necrosis. Exposing cancer cells to acidic pH in vitro significantly reduced the anti-proliferative effect of rapamycin. At the molecular level, acidity significantly decreased mTORC1 activity, suggesting that cancer cell proliferation is independent of mTORC1 in acidic conditions. In contrast, the activation of mitogen-activated protein kinase (MAPK) or AKT were not affected by acidity, and blocking MAPK or AKT with a chemical inhibitor maintained an anti-proliferative effect at low pH. In tumor mouse models, the use of sodium bicarbonate increased mTORC1 activity in cancer cells and potentiated the anti-cancer efficacy of rapamycin. Combining sodium bicarbonate with rapamycin resulted in increased tumor necrosis, increased cancer cell apoptosis and decreased cancer cell proliferation as compared to single treatment. Taken together, these results emphasize the inefficacy of mTORC1 inhibitors in acidic conditions. They further highlight the potential of combining sodium bicarbonate with mTORC1 inhibitors to improve their anti-tumoral efficacy.

  4. Dynamics of mTORC1 activation in response to amino acids

    Science.gov (United States)

    Manifava, Maria; Smith, Matthew; Rotondo, Sergio; Walker, Simon; Niewczas, Izabella; Zoncu, Roberto; Clark, Jonathan; Ktistakis, Nicholas T

    2016-01-01

    Amino acids are essential activators of mTORC1 via a complex containing RAG GTPases, RAGULATOR and the vacuolar ATPase. Sensing of amino acids causes translocation of mTORC1 to lysosomes, an obligate step for activation. To examine the spatial and temporal dynamics of this translocation, we used live imaging of the mTORC1 component RAPTOR and a cell permeant fluorescent analogue of di-leucine methyl ester. Translocation to lysosomes is a transient event, occurring within 2 min of aa addition and peaking within 5 min. It is temporally coupled with fluorescent leucine appearance in lysosomes and is sustained in comparison to aa stimulation. Sestrin2 and the vacuolar ATPase are negative and positive regulators of mTORC1 activity in our experimental system. Of note, phosphorylation of canonical mTORC1 targets is delayed compared to lysosomal translocation suggesting a dynamic and transient passage of mTORC1 from the lysosomal surface before targetting its substrates elsewhere. DOI: http://dx.doi.org/10.7554/eLife.19960.001 PMID:27725083

  5. Regulation of bone formation by baicalein via the mTORC1 pathway

    Directory of Open Access Journals (Sweden)

    Li SF

    2015-09-01

    Full Text Available Sheng-fa Li,1,2,* Jia-jun Tang,1,2,* Jian Chen,1–3,* Pei Zhang,4,* Ting Wang,5 Tian-yu Chen,1,2 Bo Yan,1,2 Bin Huang,1,2 Liang Wang,1,2 Min-jun Huang,1,2 Zhong-min Zhang,1,2 Da-di Jin1,21Academy of Orthopedics of Guangdong Province, Guangzhou, People’s Republic of China; 2Department of Orthopedics, The Third Affiliated Hospital, Southern Medical University, Guangzhou, Guangdong, People’s Republic of China; 3Three Gorges Central Hospital of Chongqing, Chongqing, People’s Republic of China; 4School of Traditional Chinese Medicine, Southern Medical University, Guangzhou, Guangdong, People’s Republic of China; 5Department of Cell Biology, School of Basic Medical Science, Southern Medical University, Guangzhou, Guangdong, People’s Republic of China*These authors contributed equally to this workAbstract: Osteoporosis is a systemic skeletal disease that is characterized by low bone density and microarchitectural deterioration of bone tissue. The increasing prevalence of osteoporosis has attracted much attention. In this study, MC3T3-E1 pre-osteoblasts were treated with the natural compound, baicalein (0.1 µmol/L, 1 µmol/L, 10 µmol/L, to stimulate differentiation over a 14-day period. In addition, a canonical ovariectomized (OVX mouse model was used to investigate the effect of 3-month baicalein treatment (10 mg/kg per day in preventing postmenopausal osteoporosis. In vitro, we found that baicalein induced activation of alkaline phosphatase, stimulated the mammalian target of rapamycin complex 1 (mTORC1 signaling pathway, and induced expression of osteoblast differentiation markers, ie, osteocalcin, osterix, collagen Iα1, and runt-related transcription factor 2 (RUNX2, in osteoblasts. In vivo, several bone parameters, including trabecular thickness, trabecular bone mineral density, and trabecular number, in the distal femoral metaphysis were significantly increased in OVX mice treated intragastrically with baicalein for 3 months

  6. Focal Adhesion- and IGF1R-Dependent Survival and Migratory Pathways Mediate Tumor Resistance to mTORC1/2 Inhibition.

    Science.gov (United States)

    Yoon, Sang-Oh; Shin, Sejeong; Karreth, Florian A; Buel, Gwen R; Jedrychowski, Mark P; Plas, David R; Dedhar, Shoukat; Gygi, Steven P; Roux, Philippe P; Dephoure, Noah; Blenis, John

    2017-08-03

    Aberrant signaling by the mammalian target of rapamycin (mTOR) contributes to the devastating features of cancer cells. Thus, mTOR is a critical therapeutic target and catalytic inhibitors are being investigated as anti-cancer drugs. Although mTOR inhibitors initially block cell proliferation, cell viability and migration in some cancer cells are quickly restored. Despite sustained inhibition of mTORC1/2 signaling, Akt, a kinase regulating cell survival and migration, regains phosphorylation at its regulatory sites. Mechanistically, mTORC1/2 inhibition promotes reorganization of integrin/focal adhesion kinase-mediated adhesomes, induction of IGFR/IR-dependent PI3K activation, and Akt phosphorylation via an integrin/FAK/IGFR-dependent process. This resistance mechanism contributes to xenograft tumor cell growth, which is prevented with mTOR plus IGFR inhibitors, supporting this combination as a therapeutic approach for cancers. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Development of hypomelanotic macules is associated with constitutive activated mTORC1 in tuberous sclerosis complex

    DEFF Research Database (Denmark)

    Møller, Lisbeth Birk; Schönewolf-Greulich, Bitten; Rosengren, Thomas

    2017-01-01

    of TSC1/2 form a complex which at energy limiting states, down-regulates the activity of the regulator of protein synthesis, the mammalian target of rapamycin complex1 (mTORC1). As expected, in contrast to cultured control fibroblasts, starvation of cultured patient fibroblasts obtained from...... a hypomelanotic macule did not lead to repression of mTORC1, whereas partial repression was observed in patient fibroblasts obtained from non-lesional skin. The findings indicate that the development of hypomelanotic macules is associated with constitutive activated mTORC1, whereas mild deregulation of mTORC1...

  8. 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.

  9. Long-lived Snell dwarf mice display increased proteostatic mechanisms that are not dependent on decreased mTORC1 activity.

    Science.gov (United States)

    Drake, Joshua C; Bruns, Danielle R; Peelor, Frederick F; Biela, Laurie M; Miller, Richard A; Miller, Benjamin F; Hamilton, Karyn L

    2015-06-01

    Maintaining proteostasis is thought to be a key factor in slowed aging. In several growth-restricted models of long-life, we have shown evidence of increased proteostatic mechanisms, suggesting that proteostasis may be a shared characteristic of slowed aging. The Snell dwarf mouse is generated through the mutation of the Pit-1 locus causing reductions in multiple hormonal growth factors and mTORC1 signaling. Snell dwarfs are one of the longest lived rodent models of slowed aging. We hypothesized that proteostatic mechanisms would be increased in Snell compared to control (Con) as in other models of slowed aging. Using D2O, we simultaneously assessed protein synthesis in multiple subcellular fractions along with DNA synthesis in skeletal muscle, heart, and liver over 2 weeks in both sexes. We also assessed mTORC1-substrate phosphorylation. Skeletal muscle protein synthesis was decreased in all protein fractions of Snell compared to Con, varied by fraction in heart, and was not different between groups in liver. DNA synthesis was lower in Snell skeletal muscle and heart but not in liver when compared to Con. The new protein to new DNA synthesis ratio was increased threefold in Snell skeletal muscle and heart compared to Con. Snell mTORC1-substrate phosphorylation was decreased only in heart and liver. No effect of sex was seen in this study. Together with our previous investigations in long-lived models, we provide evidence further supporting proteostasis as a shared characteristic of slowed aging and show that increased proteostatic mechanisms may not necessarily require a decrease in mTORC1. © 2015 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

  10. Preclinical characterization of OSI-027, a potent and selective inhibitor of mTORC1 and mTORC2: distinct from rapamycin.

    Science.gov (United States)

    Bhagwat, Shripad V; Gokhale, Prafulla C; Crew, Andrew P; Cooke, Andy; Yao, Yan; Mantis, Christine; Kahler, Jennifer; Workman, Jennifer; Bittner, Mark; Dudkin, Lorina; Epstein, David M; Gibson, Neil W; Wild, Robert; Arnold, Lee D; Houghton, Peter J; Pachter, Jonathan A

    2011-08-01

    The phosphoinositide 3-kinase (PI3K)/AKT/mTOR pathway is frequently activated in human cancers, and mTOR is a clinically validated target. mTOR forms two distinct multiprotein complexes, mTORC1 and mTORC2, which regulate cell growth, metabolism, proliferation, and survival. Rapamycin and its analogues partially inhibit mTOR through allosteric binding to mTORC1, but not mTORC2, and have shown clinical utility in certain cancers. Here, we report the preclinical characterization of OSI-027, a selective and potent dual inhibitor of mTORC1 and mTORC2 with biochemical IC(50) values of 22 nmol/L and 65 nmol/L, respectively. OSI-027 shows more than 100-fold selectivity for mTOR relative to PI3Kα, PI3Kβ, PI3Kγ, and DNA-PK. OSI-027 inhibits phosphorylation of the mTORC1 substrates 4E-BP1 and S6K1 as well as the mTORC2 substrate AKT in diverse cancer models in vitro and in vivo. OSI-027 and OXA-01 (close analogue of OSI-027) potently inhibit proliferation of several rapamycin-sensitive and -insensitive nonengineered and engineered cancer cell lines and also, induce cell death in tumor cell lines with activated PI3K-AKT signaling. OSI-027 shows concentration-dependent pharmacodynamic effects on phosphorylation of 4E-BP1 and AKT in tumor tissue with resulting tumor growth inhibition. OSI-027 shows robust antitumor activity in several different human xenograft models representing various histologies. Furthermore, in COLO 205 and GEO colon cancer xenograft models, OSI-027 shows superior efficacy compared with rapamycin. Our results further support the important role of mTOR as a driver of tumor growth and establish OSI-027 as a potent anticancer agent. OSI-027 is currently in phase I clinical trials in cancer patients. ©2011 AACR

  11. The antioxidant function of sestrins is mediated by promotion of autophagic degradation of Keap1 and Nrf2 activation and by inhibition of mTORC1.

    Science.gov (United States)

    Rhee, Sue Goo; Bae, Soo Han

    2015-11-01

    Sestrins 1 to 3 constitute a family of proteins that are induced in mammalian cells in response to environmental stressors. Despite their apparent lack of intrinsic catalytic antioxidant activity, Sestrins protect cells from oxidative stress by lowering intracellular levels of H2O2. Here we review the mechanisms by which various types of cellular stress induce Sestrin gene transcription as well as those underlying the antioxidant function of these proteins. Several transcriptional factors, including p53, HIF-1, FoxO, C/EBP-β, ATF4, Nrf2, and PGC-1α, contribute directly to the transcriptional activation of Sestrin genes in response to various types of stress. The antioxidant function of Sestrins is mediated by two main pathways. In one pathway, Sestrins promote the p62-dependent autophagic degradation of Keap1 and thereby upregulate Nrf2 signaling and the consequent expression of genes for antioxidant enzymes. In the second pathway, Sestrins block mTORC1 activation and thereby attenuate reactive oxygen species accumulation. This inhibition of mTORC1 activity is achieved either via the AMPK-dependent phosphorylation and activation of TSC2 and consequent inhibition of the GTPase Rheb or via inhibition of the GTPase Rag and consequent prevention of the lysosomal localization of mTORC1 triggered by amino acids. Elucidation of how these pathways operate individually or cooperatively under different stress conditions awaits further study. Copyright © 2015. Published by Elsevier Inc.

  12. Roles of Mitogen-Activating Protein Kinase Kinase Kinase Kinase-3 (MAP4K3) in Preterm Skeletal Muscle Satellite Cell Myogenesis and Mammalian Target of Rapamycin Complex 1 (mTORC1) Activation Regulation.

    Science.gov (United States)

    Guo, Chu-Yi; Yu, Mu-Xue; Dai, Jie-Min; Pan, Si-Nian; Lu, Zhen-Tong; Qiu, Xiao-Shan; Zhuang, Si-Qi

    2017-07-21

    BACKGROUND Preterm skeletal muscle genesis is a paradigm for myogenesis. The role of mitogen-activating protein kinase kinase kinase kinase-3 (MAP4K3) in preterm skeletal muscle satellite cells myogenesis or its relationship to mammalian target of rapamycin complex 1 (mTORC1) activity have not been previously elaborated. MATERIAL AND METHODS Small interfering RNA (siRNA) interference technology was used to inhibit MAP4K3 expression. Leucine stimulation experiments were performed following MAP4K3-siRNA interference. The differentiation of primary preterm skeletal muscle satellite cells was observed after siRNA-MAP4K3 interference. Western blot analysis was used to determine the expression of MAP4K3, MyHC, MyoD, myogenin, p-mTOR, and p-S6K1. The immunofluorescence fusion index of MyHC and myogenin were detected. MAP4K3 effects on preterm rat satellite cells differentiation and its relationship to mTORC1 activity are reported. RESULTS MAP4K3 siRNA knockdown inhibited myotube formation and both MyoD and myogenin expression in primary preterm rat skeletal muscle satellite cells, but MAP4K3 siRNA had no effect on the activity of mTORC1. In primary preterm rat skeletal muscle satellite cells, MAP4K3 knockdown resulted in significantly weaker, but not entirely blunted, leucine-induced mTORC1 signaling. CONCLUSIONS MAP4K3 positively regulates preterm skeletal muscle satellite cell myogenesis, but may not regulate mTORC1 activity. MAP4K3 may play a role in mTORC1 full activation in response to leucine.

  13. Selective interference of mTORC1/RAPTOR protects against human disc cellular apoptosis, senescence, and extracellular matrix catabolism with Akt and autophagy induction.

    Science.gov (United States)

    Ito, M; Yurube, T; Kakutani, K; Maeno, K; Takada, T; Terashima, Y; Kakiuchi, Y; Takeoka, Y; Miyazaki, S; Kuroda, R; Nishida, K

    2017-12-01

    The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that integrates nutrients to execute cell growth and protein synthesis. We hypothesized that mTOR is essential for the intervertebral disc, the largest avascular, low-nutrient organ. Our objective was to elucidate roles of mTOR signaling in human disc cells. The mTOR exists in two complexes: mTORC1 containing the regulatory-associated protein of mTOR (RAPTOR) and mTORC2 containing the rapamycin-insensitive companion of mTOR (RICTOR). To analyze their functions in human disc nucleus pulposus cells, RNA interference (RNAi) of mTOR targeting mTORC1 and mTORC2, RAPTOR targeting mTORC1, or RICTOR targeting mTORC2 or rapamycin, a pharmacological mTORC1 inhibitor, was applied. First, mTOR signaling including Akt, p70/ribosomal S6 kinase (p70/S6K), and autophagy were assessed. Then, apoptosis, senescence, and matrix metabolism were evaluated under pro-inflammatory interleukin-1 beta (IL-1β) stimulation. Western blotting showed significant decreases in specific proteins by each RNAi (all P RAPTOR RNAi decreased p70/S6K but increased Akt phosphorylation. All RNAi treatments increased light chain 3 (LC3)-II and decreased p62/sequestosome 1 (p62/SQSTM1), indicating enhanced autophagy. In apoptosis, IL-1β-induced terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells and poly (ADP-ribose) polymerase (PARP) and caspase-9 cleavage decreased by RAPTOR RNAi. In senescence, IL-1β-induced senescence-associated beta-galactosidase (SA-β-gal)-positive cells and p16/INK4A expression also decreased by RAPTOR RNAi. In matrix metabolism, RAPTOR RNAi reduced IL-1β-induced catabolic matrix metalloproteinase (MMP) release and activation and up-regulated anabolic gene expression. These findings were all consistent with rapamycin administration. Additional disc-tissue analysis detected expression and phosphorylation of mTOR-signaling molecules in varying ages. Selective interference of mTORC1

  14. mTORC1 Is a Local, Postsynaptic Voltage Sensor Regulated by Positive and Negative Feedback Pathways

    Directory of Open Access Journals (Sweden)

    Farr Niere

    2017-05-01

    Full Text Available The mammalian/mechanistic target of rapamycin complex 1 (mTORC1 serves as a regulator of mRNA translation. Recent studies suggest that mTORC1 may also serve as a local, voltage sensor in the postsynaptic region of neurons. Considering biochemical, bioinformatics and imaging data, we hypothesize that the activity state of mTORC1 dynamically regulates local membrane potential by promoting and repressing protein synthesis of select mRNAs. Our hypothesis suggests that mTORC1 uses positive and negative feedback pathways, in a branch-specific manner, to maintain neuronal excitability within an optimal range. In some dendritic branches, mTORC1 activity oscillates between the “On” and “Off” states. We define this as negative feedback. In contrast, positive feedback is defined as the pathway that leads to a prolonged depolarized or hyperpolarized resting membrane potential, whereby mTORC1 activity is constitutively on or off, respectively. We propose that inactivation of mTORC1 increases the expression of voltage-gated potassium alpha (Kv1.1 and 1.2 and beta (Kvβ2 subunits, ensuring that the membrane resets to its resting membrane potential after experiencing increased synaptic activity. In turn, reduced mTORC1 activity increases the protein expression of syntaxin-1A and promotes the surface expression of the ionotropic glutamate receptor N-methyl-D-aspartate (NMDA-type subunit 1 (GluN1 that facilitates increased calcium entry to turn mTORC1 back on. Under conditions such as learning and memory, mTORC1 activity is required to be high for longer periods of time. Thus, the arm of the pathway that promotes syntaxin-1A and Kv1 protein synthesis will be repressed. Moreover, dendritic branches that have low mTORC1 activity with increased Kv expression would balance dendrites with constitutively high mTORC1 activity, allowing for the neuron to maintain its overall activity level within an ideal operating range. Finally, such a model suggests that recruitment of more positive feedback dendritic branches within a neuron is likely to lead to neurodegenerative disorders.

  15. Sleep deprivation impairs memory by attenuating mTORC1-dependent protein synthesis.

    Science.gov (United States)

    Tudor, Jennifer C; Davis, Emily J; Peixoto, Lucia; Wimmer, Mathieu E; van Tilborg, Erik; Park, Alan J; Poplawski, Shane G; Chung, Caroline W; Havekes, Robbert; Huang, Jiayan; Gatti, Evelina; Pierre, Philippe; Abel, Ted

    2016-04-26

    Sleep deprivation is a public health epidemic that causes wide-ranging deleterious consequences, including impaired memory and cognition. Protein synthesis in hippocampal neurons promotes memory and cognition. The kinase complex mammalian target of rapamycin complex 1 (mTORC1) stimulates protein synthesis by phosphorylating and inhibiting the eukaryotic translation initiation factor 4E-binding protein 2 (4EBP2). We investigated the involvement of the mTORC1-4EBP2 axis in the molecular mechanisms mediating the cognitive deficits caused by sleep deprivation in mice. Using an in vivo protein translation assay, we found that loss of sleep impaired protein synthesis in the hippocampus. Five hours of sleep loss attenuated both mTORC1-mediated phosphorylation of 4EBP2 and the interaction between eukaryotic initiation factor 4E (eIF4E) and eIF4G in the hippocampi of sleep-deprived mice. Increasing the abundance of 4EBP2 in hippocampal excitatory neurons before sleep deprivation increased the abundance of phosphorylated 4EBP2, restored the amount of eIF4E-eIF4G interaction and hippocampal protein synthesis to that seen in mice that were not sleep-deprived, and prevented the hippocampus-dependent memory deficits associated with sleep loss. These findings collectively demonstrate that 4EBP2-regulated protein synthesis is a critical mediator of the memory deficits caused by sleep deprivation. Copyright © 2016, American Association for the Advancement of Science.

  16. Rac1 Regulates the Activity of mTORC1 and mTORC2 and Controls Cellular Size

    Science.gov (United States)

    Saci, Abdelhafid; Cantley, Lewis C.; Carpenter, Christopher L.

    2013-01-01

    SUMMARY Mammalian target of rapamycin (mTOR) is a serine/threonine kinase that exists in two separate complexes, mTORC1 and mTORC2, that function to control cell size and growth in response to growth factors, nutrients, and cellular energy levels. Low molecular weight GTP-binding proteins of the Rheb and Rag families are key regulators of the mTORC1 complex, but regulation of mTORC2 is poorly understood. Here, we report that Rac1, a member of the Rho family of GTPases, is a critical regulator of both mTORC1 and mTORC2 in response to growth-factor stimulation. Deletion of Rac1 in primary cells using an inducible-Cre/Lox approach inhibits basal and growth-factor activation of both mTORC1 and mTORC2. Rac1 appears to bind directly to mTOR and to mediate mTORC1 and mTORC2 localization at specific membranes. Binding of Rac1 to mTOR does not depend on the GTP-bound state of Rac1, but on the integrity of its C-terminal domain. This function of Rac1 provides a means to regulate mTORC1 and mTORC2 simultaneously. PMID:21474067

  17. ULK1 regulates melanin levels in MNT-1 cells independently of mTORC1.

    Directory of Open Access Journals (Sweden)

    Eyal Kalie

    Full Text Available Melanosomes are lysosome-related organelles that serve as specialized sites of melanin synthesis and storage in melanocytes. The progression of melanosomes through the different stages of their formation requires trafficking of specific proteins and membrane constituents in a sequential manner, which is likely to deploy ubiquitous cellular machinery along with melanocyte-specific proteins. Recent evidence revealed a connection between melanogenesis and the autophagy machinery, suggesting a novel role for members of the latter in melanocytes. Here we focused on ULK1, a key autophagy protein which is negatively regulated by mTORC1, to assess its potential role in melanogenesis in MNT-1 cells. We found that ULK1 depletion causes an increase in melanin levels, suggesting an inhibitory function for this protein in melanogenesis. Furthermore, this increase was accompanied by increased transcription of MITF (microphthalmia-associated transcription factor and tyrosinase and by elevated protein levels of tyrosinase, the rate-limiting factor in melanin biogenesis. We also provide evidence to show that ULK1 function in this context is independent of the canonical ULK1 autophagy partners, ATG13 and FIP200. Furthermore we show that regulation of melanogenesis by ULK1 is independent of mTORC1 inhibition. Our data thus provide intriguing insights regarding the involvement of the key regulatory autophagy machinery in melanogenesis.

  18. Adaptive Noise Suppression Using Digital Signal Processing

    Science.gov (United States)

    Kozel, David; Nelson, Richard

    1996-01-01

    A signal to noise ratio dependent adaptive spectral subtraction algorithm is developed to eliminate noise from noise corrupted speech signals. The algorithm determines the signal to noise ratio and adjusts the spectral subtraction proportion appropriately. After spectra subtraction low amplitude signals are squelched. A single microphone is used to obtain both eh noise corrupted speech and the average noise estimate. This is done by determining if the frame of data being sampled is a voiced or unvoiced frame. During unvoice frames an estimate of the noise is obtained. A running average of the noise is used to approximate the expected value of the noise. Applications include the emergency egress vehicle and the crawler transporter.

  19. Activation of mTORC1 by leucine is potentiated by branched-chain amino acids and even more so by essential amino acids following resistance exercise

    DEFF Research Database (Denmark)

    Moberg, Marcus; Apró, William; Ekblom, Björn

    2016-01-01

    Protein synthesis is stimulated by resistance exercise and intake of amino acids, in particular leucine. Moreover, activation of mammalian target of rapamycin complex 1 (mTORC1) signaling by leucine is potentiated by the presence of other essential amino acids (EAA). However, the contribution...... of the branched-chain amino acids (BCAA) to this effect is yet unknown. Here we compare the stimulatory role of leucine, BCAA, and EAA ingestion on anabolic signaling following exercise. Accordingly, eight trained volunteers completed four sessions of resistance exercise during which they ingested either placebo......, leucine, BCAA, or EAA (including the BCAA) in random order. Muscle biopsies were taken at rest, immediately after exercise, and following 90 and 180 min of recovery. Following 90 min of recovery the activity of S6 kinase 1 (S6K1) was greater than at rest in all four trials (PlaceboLeucine

  20. Computational analysis of an autophagy/translation switch based on mutual inhibition of MTORC1 and ULK1.

    Directory of Open Access Journals (Sweden)

    Paulina Szymańska

    Full Text Available We constructed a mechanistic, computational model for regulation of (macroautophagy and protein synthesis (at the level of translation. The model was formulated to study the system-level consequences of interactions among the following proteins: two key components of MTOR complex 1 (MTORC1, namely the protein kinase MTOR (mechanistic target of rapamycin and the scaffold protein RPTOR; the autophagy-initiating protein kinase ULK1; and the multimeric energy-sensing AMP-activated protein kinase (AMPK. Inputs of the model include intrinsic AMPK kinase activity, which is taken as an adjustable surrogate parameter for cellular energy level or AMP:ATP ratio, and rapamycin dose, which controls MTORC1 activity. Outputs of the model include the phosphorylation level of the translational repressor EIF4EBP1, a substrate of MTORC1, and the phosphorylation level of AMBRA1 (activating molecule in BECN1-regulated autophagy, a substrate of ULK1 critical for autophagosome formation. The model incorporates reciprocal regulation of mTORC1 and ULK1 by AMPK, mutual inhibition of MTORC1 and ULK1, and ULK1-mediated negative feedback regulation of AMPK. Through analysis of the model, we find that these processes may be responsible, depending on conditions, for graded responses to stress inputs, for bistable switching between autophagy and protein synthesis, or relaxation oscillations, comprising alternating periods of autophagy and protein synthesis. A sensitivity analysis indicates that the prediction of oscillatory behavior is robust to changes of the parameter values of the model. The model provides testable predictions about the behavior of the AMPK-MTORC1-ULK1 network, which plays a central role in maintaining cellular energy and nutrient homeostasis.

  1. La-related protein 1 (LARP1) represses terminal oligopyrimidine (TOP) mRNA translation downstream of mTOR complex 1 (mTORC1)

    DEFF Research Database (Denmark)

    Fonseca, Bruno; Zakaria, Chadi; Jia, J J

    2015-01-01

    The mammalian target of rapamycin complex 1 (mTORC1) is a critical regulator of protein synthesis. The best studied targets of mTORC1 in translation are the eukaryotic initiation factor-binding protein 1 (4E-BP1) and ribosomal protein S6 kinase 1 (S6K1). In this study, we identify the La-related ...

  2. mTORC1 activity as a determinant of cancer risk--rationalizing the cancer-preventive effects of adiponectin, metformin, rapamycin, and low-protein vegan diets.

    Science.gov (United States)

    McCarty, Mark F

    2011-10-01

    Increased plasma levels of adiponectin, metformin therapy of diabetes, rapamycin administration in transplant patients, and lifelong consumption of low-protein plant-based diets have all been linked to decreased risk for various cancers. These benefits may be mediated, at least in part, by down-regulated activity of the mTORC1 complex, a key regulator of protein translation. By boosting the effective availability of the translation initiator eIF4E, mTORC1 activity promotes the translation of a number of "weak" mRNAs that code for proteins, often up-regulated in cancer, that promote cellular proliferation, invasiveness, and angiogenesis, and that abet cancer promotion and chemoresistance by opposing apoptosis. Measures which inhibit eIF4E activity, either directly or indirectly, may have utility not only for cancer prevention, but also for the treatment of many cancers in which eIF4E drives malignancy. Since eIF4E is overexpressed in many cancers, strategies which target eIF4E directly--some of which are now being assessed clinically--may have the broadest efficacy in this regard. Many of the "weak" mRNAs coding for proteins that promote malignant behavior or chemoresistance are regulated transcriptionally by NF-kappaB and/or Stat3, which are active in a high proportion of cancers; thus, regimens concurrently targeting eIF4E, NF-kappaB, and Stat3 may suppress these proteins at both the transcriptional and translational levels, potentially achieving a very marked reduction in their expression. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Tumor suppressive role of sestrin2 during colitis and colon carcinogenesis

    Science.gov (United States)

    Ro, Seung-Hyun; Xue, Xiang; Ramakrishnan, Sadeesh K; Cho, Chun-Seok; Namkoong, Sim; Jang, Insook; Semple, Ian A; Ho, Allison; Park, Hwan-Woo; Shah, Yatrik M; Lee, Jun Hee

    2016-01-01

    The mTOR complex 1 (mTORC1) and endoplasmic reticulum (ER) stress pathways are critical regulators of intestinal inflammation and colon cancer growth. Sestrins are stress-inducible proteins, which suppress both mTORC1 and ER stress; however, the role of Sestrins in colon physiology and tumorigenesis has been elusive due to the lack of studies in human tissues or in appropriate animal models. In this study, we show that human SESN2 expression is elevated in the colon of ulcerative colitis patients but is lost upon p53 inactivation during colon carcinogenesis. In mouse colon, Sestrin2 was critical for limiting ER stress and promoting the recovery of epithelial cells after inflammatory injury. During colitis-promoted tumorigenesis, Sestrin2 was shown to be an important mediator of p53’s control over mTORC1 signaling and tumor cell growth. These results highlight Sestrin2 as a novel tumor suppressor, whose downregulation can accelerate both colitis and colon carcinogenesis. DOI: http://dx.doi.org/10.7554/eLife.12204.001 PMID:26913956

  4. Ablation of TSC2 enhances insulin secretion by increasing the number of mitochondria through activation of mTORC1.

    Directory of Open Access Journals (Sweden)

    Maki Koyanagi

    Full Text Available AIM: We previously found that chronic tuberous sclerosis protein 2 (TSC2 deletion induces activation of mammalian target of rapamycin Complex 1 (mTORC1 and leads to hypertrophy of pancreatic beta cells from pancreatic beta cell-specific TSC2 knockout (βTSC2(-/- mice. The present study examines the effects of TSC2 ablation on insulin secretion from pancreatic beta cells. METHODS: Isolated islets from βTSC2(-/- mice and TSC2 knockdown insulin 1 (INS-1 insulinoma cells treated with small interfering ribonucleic acid were used to investigate insulin secretion, ATP content and the expression of mitochondrial genes. RESULTS: Activation of mTORC1 increased mitochondrial DNA expression, mitochondrial density and ATP production in pancreatic beta cells of βTSC2(-/- mice. In TSC2 knockdown INS-1 cells, mitochondrial DNA expression, mitochondrial density and ATP production were increased compared with those in control INS-1 cells, consistent with the phenotype of βTSC2(-/- mice. TSC2 knockdown INS-1 cells also exhibited augmented insulin secretory response to glucose. Rapamycin inhibited mitochondrial DNA expression and ATP production as well as insulin secretion in response to glucose. Thus, βTSC2(-/- mice exhibit hyperinsulinemia due to an increase in the number of mitochondria as well as enlargement of individual beta cells via activation of mTORC1. CONCLUSION: Activation of mTORC1 by TSC2 ablation increases mitochondrial biogenesis and enhances insulin secretion from pancreatic beta cells.

  5. Impact of dual mTORC1/2 mTOR kinase inhibitor AZD8055 on acquired endocrine resistance in breast cancer in vitro

    Science.gov (United States)

    2014-01-01

    Introduction Upregulation of PI3K/Akt/mTOR signalling in endocrine-resistant breast cancer (BC) has identified mTOR as an attractive target alongside anti-hormones to control resistance. RAD001 (everolimus/Afinitor®), an allosteric mTOR inhibitor, is proving valuable in this setting; however, some patients are inherently refractory or relapse during treatment requiring alternative strategies. Here we evaluate the potential for novel dual mTORC1/2 mTOR kinase inhibitors, exemplified by AZD8055, by comparison with RAD001 in ER + endocrine resistant BC cells. Methods In vitro models of tamoxifen (TamR) or oestrogen deprivation resistance (MCF7-X) were treated with RAD001 or AZD8055 alone or combined with anti-hormone fulvestrant. Endpoints included growth, cell proliferation (Ki67), viability and migration, with PI3K/AKT/mTOR signalling impact monitored by Western blotting. Potential ER cross-talk was investigated by immunocytochemistry and RT-PCR. Results RAD001 was a poor growth inhibitor of MCF7-derived TamR and MCF7-X cells (IC50 ≥1 μM), rapidly inhibiting mTORC1 but not mTORC2/AKT signalling. In contrast AZD8055, which rapidly inhibited both mTORC1 and mTORC2/AKT activity, was a highly effective (P T47D-derived tamoxifen resistant model T47D-tamR (IC50 19 nM). AZD8055 significantly (P <0.05) inhibited resistant cell proliferation, increased cell death and reduced migration. Furthermore, dual treatment of TamR or MCF7-X cells with AZD8055 plus fulvestrant provided superior control of resistant growth versus either agent alone (P <0.05). Co-treating with AZD8055 alongside tamoxifen (P <0.01) or oestrogen deprivation (P <0.05) also effectively inhibited endocrine responsive MCF-7 cells. Although AZD8055 inhibited oestrogen receptor (ER) ser167 phosphorylation in TamR and MCF7-X, it had no effect on ER ser118 activity or expression of several ER-regulated genes, suggesting the mTOR kinase inhibitor impact was largely ER-independent. The capacity of

  6. PDMP, a ceramide analogue, acts as an inhibitor of mTORC1 by inducing its translocation from lysosome to endoplasmic reticulum.

    Science.gov (United States)

    Ode, Takashi; Podyma-Inoue, Katarzyna A; Terasawa, Kazue; Inokuchi, Jin-Ichi; Kobayashi, Toshihide; Watabe, Tetsuro; Izumi, Yuichi; Hara-Yokoyama, Miki

    2017-01-01

    Mammalian or mechanistic target of rapamycin complex 1 (mTORC1) is a master regulator of cell growth, metabolism, and cell differentiation. Recent studies have revealed that the recruitment of mTORC1 to lysosomes is essential for its activation. The ceramide analogue 1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP), a well known glycosphingolipid synthesis inhibitor, also affects the structures and functions of various organelles, including lysosomes and endoplasmic reticulum (ER). We investigated whether PDMP regulates the mTORC1 activity through its effects on organellar behavior. PDMP induced the translocation of mTORC1 from late endosomes/lysosomes, leading to the dissociation of mTORC1 from its activator Rheb in MC3T3-E1 cells. Surprisingly, we found mTORC1 translocation to the ER upon PDMP treatment. This effect of PDMP was independent of its action as the inhibitor, since two stereoisomers of PDMP, with and without the inhibitor activity, showed essentially the same effect. We confirmed that PDMP inhibits the mTORC1 activity based on the decrease in the phosphorylation of ribosomal S6 kinase, a downstream target of mTORC1, and the increase in LC3 puncta, reflecting autophagosome formation. Furthermore, PDMP inhibited the mTORC1-dependent osteoblastic cell proliferation and differentiation of MC3T3-E1 cells. Accordingly, the present results reveal a novel mechanism of PDMP, which inhibits the mTORC1 activity by inducing the translocation of mTOR from lysosomes to the ER. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Arsenite suppression of BMP signaling in human keratinocytes

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Marjorie A.; Qin, Qin [Department of Environmental Toxicology, University of California, Davis, CA 95616-8588 (United States); Hu, Qin; Zhao, Bin [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Rice, Robert H., E-mail: rhrice@ucdavis.edu [Department of Environmental Toxicology, University of California, Davis, CA 95616-8588 (United States)

    2013-06-15

    Arsenic, a human skin carcinogen, suppresses differentiation of cultured keratinocytes. Exploring the mechanism of this suppression revealed that BMP-6 greatly increased levels of mRNA for keratins 1 and 10, two of the earliest differentiation markers expressed, a process prevented by co-treatment with arsenite. BMP also stimulated, and arsenite suppressed, mRNA for FOXN1, an important transcription factor driving early keratinocyte differentiation. Keratin mRNAs increased slowly after BMP-6 addition, suggesting they are indirect transcriptional targets. Inhibition of Notch1 activation blocked BMP induction of keratins 1 and 10, while FOXN1 induction was largely unaffected. Supporting a requirement for Notch1 signaling in keratin induction, BMP increased levels of activated Notch1, which was blocked by arsenite. BMP also greatly decreased active ERK, while co-treatment with arsenite maintained active ERK. Inhibition of ERK signaling mimicked BMP by inducing keratin and FOXN1 mRNAs and by increasing active Notch1, effects blocked by arsenite. Of 6 dual-specificity phosphatases (DUSPs) targeting ERK, two were induced by BMP unless prevented by simultaneous exposure to arsenite and EGF. Knockdown of DUSP2 or DUSP14 using shRNAs greatly reduced FOXN1 and keratins 1 and 10 mRNA levels and their induction by BMP. Knockdown also decreased activated Notch1, keratin 1 and keratin 10 protein levels, both in the presence and absence of BMP. Thus, one of the earliest effects of BMP is induction of DUSPs, which increases FOXN1 transcription factor and activates Notch1, both required for keratin gene expression. Arsenite prevents this cascade by maintaining ERK signaling, at least in part by suppressing DUSP expression. - Highlights: • BMP induces FOXN1 transcription. • BMP induces DUSP2 and DUSP14, suppressing ERK activation. • Arsenite suppresses levels of phosphorylated Smad1/5 and FOXN1 and DUSP mRNA. • These actions rationalize arsenite suppression of keratinocyte

  8. Metformin inhibition of mTORC1 activation, DNA synthesis and proliferation in pancreatic cancer cells: Dependence on glucose concentration and role of AMPK

    Energy Technology Data Exchange (ETDEWEB)

    Sinnett-Smith, James; Kisfalvi, Krisztina; Kui, Robert [Division of Digestive Diseases, Department of Medicine, CURE: Digestive Diseases Research Center, David Geffen School of Medicine and Molecular Biology Institute, University of California at Los Angeles, CA (United States); Rozengurt, Enrique, E-mail: erozengurt@mednet.ucla.edu [Division of Digestive Diseases, Department of Medicine, CURE: Digestive Diseases Research Center, David Geffen School of Medicine and Molecular Biology Institute, University of California at Los Angeles, CA (United States)

    2013-01-04

    Highlights: Black-Right-Pointing-Pointer Metformin inhibits cancer cell growth but the mechanism(s) are not understood. Black-Right-Pointing-Pointer We show that the potency of metformin is sharply dependent on glucose in the medium. Black-Right-Pointing-Pointer AMPK activation was enhanced in cancer cells incubated in physiological glucose. Black-Right-Pointing-Pointer Reciprocally, metformin potently inhibited mTORC1, DNA synthesis and proliferation. Black-Right-Pointing-Pointer Metformin, at low concentrations, inhibited DNA synthesis through AMPK. -- Abstract: Metformin, a widely used anti-diabetic drug, is emerging as a potential anticancer agent but the mechanisms involved remain incompletely understood. Here, we demonstrate that the potency of metformin induced AMPK activation, as shown by the phosphorylation of its substrates acetyl-CoA carboxylase (ACC) at Ser{sup 79} and Raptor at Ser{sup 792}, was dramatically enhanced in human pancreatic ductal adenocarcinoma (PDAC) cells PANC-1 and MiaPaCa-2 cultured in medium containing physiological concentrations of glucose (5 mM), as compared with parallel cultures in medium with glucose at 25 mM. In physiological glucose, metformin inhibited mTORC1 activation, DNA synthesis and proliferation of PDAC cells stimulated by crosstalk between G protein-coupled receptors and insulin/IGF signaling systems, at concentrations (0.05-0.1 mM) that were 10-100-fold lower than those used in most previous reports. Using siRNA-mediated knockdown of the {alpha}{sub 1} and {alpha}{sub 2} catalytic subunits of AMPK, we demonstrated that metformin, at low concentrations, inhibited DNA synthesis through an AMPK-dependent mechanism. Our results emphasize the importance of using medium containing physiological concentrations of glucose to elucidate the anticancer mechanism of action of metformin in pancreatic cancer cells and other cancer cell types.

  9. STRADα deficiency results in aberrant mTORC1 signaling during corticogenesis in humans and mice

    OpenAIRE

    Orlova, Ksenia A.; Parker, Whitney E.; Heuer, Gregory G.; Tsai, Victoria; Yoon, Jason; Baybis, Marianna; Fenning, Robert S.; Strauss, Kevin; Crino, Peter B.

    2010-01-01

    Polyhydramnios, megalencephaly, and symptomatic epilepsy syndrome (PMSE) is a rare human autosomal-recessive disorder characterized by abnormal brain development, cognitive disability, and intractable epilepsy. It is caused by homozygous deletions of STE20-related kinase adaptor α (STRADA). The underlying pathogenic mechanisms of PMSE and the role of STRADA in cortical development remain unknown. Here, we found that a human PMSE brain exhibits cytomegaly, neuronal heterotopia, and aberrant ac...

  10. La-related Protein 1 (LARP1) Represses Terminal Oligopyrimidine (TOP) mRNA Translation Downstream of mTOR Complex 1 (mTORC1).

    Science.gov (United States)

    Fonseca, Bruno D; Zakaria, Chadi; Jia, Jian-Jun; Graber, Tyson E; Svitkin, Yuri; Tahmasebi, Soroush; Healy, Danielle; Hoang, Huy-Dung; Jensen, Jacob M; Diao, Ilo T; Lussier, Alexandre; Dajadian, Christopher; Padmanabhan, Niranjan; Wang, Walter; Matta-Camacho, Edna; Hearnden, Jaclyn; Smith, Ewan M; Tsukumo, Yoshinori; Yanagiya, Akiko; Morita, Masahiro; Petroulakis, Emmanuel; González, Jose L; Hernández, Greco; Alain, Tommy; Damgaard, Christian K

    2015-06-26

    The mammalian target of rapamycin complex 1 (mTORC1) is a critical regulator of protein synthesis. The best studied targets of mTORC1 in translation are the eukaryotic initiation factor-binding protein 1 (4E-BP1) and ribosomal protein S6 kinase 1 (S6K1). In this study, we identify the La-related protein 1 (LARP1) as a key novel target of mTORC1 with a fundamental role in terminal oligopyrimidine (TOP) mRNA translation. Recent genome-wide studies indicate that TOP and TOP-like mRNAs compose a large portion of the mTORC1 translatome, but the mechanism by which mTORC1 controls TOP mRNA translation is incompletely understood. Here, we report that LARP1 functions as a key repressor of TOP mRNA translation downstream of mTORC1. Our data show the following: (i) LARP1 associates with mTORC1 via RAPTOR; (ii) LARP1 interacts with TOP mRNAs in an mTORC1-dependent manner; (iii) LARP1 binds the 5'TOP motif to repress TOP mRNA translation; and (iv) LARP1 competes with the eukaryotic initiation factor (eIF) 4G for TOP mRNA binding. Importantly, from a drug resistance standpoint, our data also show that reducing LARP1 protein levels by RNA interference attenuates the inhibitory effect of rapamycin, Torin1, and amino acid deprivation on TOP mRNA translation. Collectively, our findings demonstrate that LARP1 functions as an important repressor of TOP mRNA translation downstream of mTORC1. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Divergent Metabolic Regulation of Autophagy and mTORC1—Early Events in Alzheimer’s Disease?

    Directory of Open Access Journals (Sweden)

    Mai A. Shafei

    2017-06-01

    Full Text Available Alzheimer’s disease (AD is a progressive disease associated with the production and deposition of amyloid β-peptide (Aβ aggregates and neurofibrillary tangles, which lead to synaptic and neuronal damage. Reduced autophagic flux has been widely associated with the accumulation of autophagic vacuoles (AV, which has been proposed to contribute to aggregate build-up observed in AD. As such, targeting autophagy regulation has received wide review, where an understanding as to how this mechanism can be controlled will be important to neuronal health. The mammalian target of rapamycin complex 1 (mTORC1, which was found to be hyperactive in AD brain, regulates autophagy and is considered to be mechanistically important to aberrant autophagy in AD. Hormones and nutrients such as insulin and leucine, respectively, positively regulate mTORC1 activation and are largely considered to inhibit autophagy. However, in AD brain there is a dysregulation of nutrient metabolism, linked to insulin resistance, where a role for insulin treatment to improve cognition has been proposed. Recent studies have highlighted that mitochondrial proteins such as glutamate dehydrogenase and the human branched chain aminotransferase protein, through metabolism of leucine and glutamate, differentially regulate mTORC1 and autophagy. As the levels of the hBCAT proteins are significantly increased in AD brain relative to aged-matched controls, we discuss how these metabolic pathways offer new potential therapeutic targets. In this review article, we highlight the core regulation of autophagy through mTORC1, focusing on how insulin and leucine will be important to consider in particular with respect to our understanding of nutrient load and AD pathogenesis.

  12. VHF signal power suppression in stratiform and convective precipitation

    Directory of Open Access Journals (Sweden)

    A. J. McDonald

    2006-03-01

    Full Text Available Previous studies have indicated that VHF clear-air radar return strengths are reduced during periods of precipitation. This study aims to examine whether the type of precipitation, stratiform and convective precipitation types are identified, has any impact on the relationships previously observed and to examine the possible mechanisms which produce this phenomenon. This study uses a combination of UHF and VHF wind-profiler data to define periods associated with stratiform and convective precipitation. This identification is achieved using an algorithm which examines the range squared corrected signal to noise ratio of the UHF returns for a bright band signature for stratiform precipitation. Regions associated with convective rainfall have been defined by identifying regions of enhanced range corrected signal to noise ratio that do not display a bright band structure and that are relatively uniform until a region above the melting layer.

    This study uses a total of 68 days, which incorporated significant periods of surface rainfall, between 31 August 2000 and 28 February 2002 inclusive from Aberystwyth (52.4° N, 4.1° W. Examination suggests that both precipitation types produce similar magnitude reductions in VHF signal power on average. However, the frequency of occurrence of statistically significant reductions in VHF signal power are very different. In the altitude range 2-4 km stratiform precipitation is related to VHF signal suppression approximately 50% of the time while in convective precipitation suppression is observed only 27% of the time. This statistical result suggests that evaporation, which occurs more often in stratiform precipitation, is important in reducing the small-scale irregularities in humidity and thereby the radio refractive index. A detailed case study presented also suggests that evaporation reducing small-scale irregularities in humidity may contribute to the observed VHF signal

  13. Silymarin Suppresses Cellular Inflammation By Inducing Reparative Stress Signaling

    Energy Technology Data Exchange (ETDEWEB)

    Lovelace, Erica S.; Wagoner, Jessica; MacDonald, James; Bammler, Theo; Bruckner, Jacob; Brownell, Jessica; Beyer, Richard; Zink, Erika M.; Kim, Young-Mo; Kyle, Jennifer E.; Webb-Robertson, Bobbie-Jo M.; Waters, Katrina M.; Metz, Thomas O.; Farin, Federico; Oberlies, Nicholas H.; Polyak, Steve

    2015-08-28

    Silymarin (SM), a natural product, is touted as a liver protectant and preventer of both chronic inflammation and diseases. To define how SM elicits these effects at a systems level, we performed transcriptional profiling, metabolomics, and signaling studies in human liver and T cell lines. Multiple pathways associated with cellular stress and metabolism were modulated by SM treatment within 0.5 to four hours: activation of Activating Transcription Factor 4 (ATF-4) and adenosine monophosphate protein kinase (AMPK) and inhibition of mammalian target of rapamycin (mTOR) signaling, the latter being associated with induction of DNA-damage-inducible transcript 4 (DDIT4). Metabolomics analyses revealed suppression of glycolytic, TCA cycle, and amino acid metabolism by SM treatment. Antiinflammatory effects arose with prolonged (i.e. 24 hours) SM exposure, with suppression of multiple proinflammatory mRNAs and nuclear factor kappa B (NF-κB) and forkhead box O (FOXO) signaling. Studies with murine knock out cells revealed that SM inhibition of both mTOR and NF-κB was partially AMPK dependent, while SM inhibition of the mTOR pathway in part required DDIT4. Thus, SM activates stress and repair responses that culminate in an anti-inflammatory phenotype. Other natural products induced similar stress responses, which correlated with their ability to suppress inflammation. Therefore, natural products like SM may be useful as tools to define how metabolic, stress, and repair pathways regulate cellular inflammation.

  14. IL-2- and IL-15-induced activation of the rapamycin-sensitive mTORC1 pathway in malignant CD4+ T lymphocytes

    DEFF Research Database (Denmark)

    Marzec, Michal; Liu, Xiaobin; Kasprzycka, Monika

    2008-01-01

    as the PI3K/Akt and MEK/ERK pathways, the IL-2-dependent cell lines activated the pathways in response to IL-2 and IL-15 but not IL-21. Activation of mTORC1 and MEK/ERK was nutrient dependent. The mTORC1, PI3K/Akt, and MEK/ERK pathways could also be activated by IL-2 in the primary leukemic, mitogen...... effect on their apoptotic rate when used as a single agent. Activation of the mTORC1, PI3K/Akt, and MEK/ERK pathways was strictly dependent on the Jak3 and Jak1 kinases. Finally, mTORC1 activation was transduced preferentially through the PI3K/Akt pathway. These findings document the selective gammac...

  15. Simultaneous inhibition of mTOR-containing complex 1 (mTORC1) and MNK induces apoptosis of cutaneous T-cell lymphoma (CTCL) cells

    DEFF Research Database (Denmark)

    Marzec, Michal Tomasz; Liu, Xiaobin; Wysocka, Maria

    2011-01-01

    mTOR kinase forms the mTORC1 complex by associating with raptor and other proteins and affects a number of key cell functions. mTORC1 activates p70S6kinase 1 (p70S6K1) and inhibits 4E-binding protein 1 (4E-BP1). In turn, p70S6K1 phosphorylates a S6 protein of the 40S ribosomal subunit (S6rp) and 4E...

  16. LARP1 functions as a molecular switch for mTORC1-mediated translation of an essential class of mRNAs.

    Science.gov (United States)

    Hong, Sungki; Freeberg, Mallory A; Han, Ting; Kamath, Avani; Yao, Yao; Fukuda, Tomoko; Suzuki, Tsukasa; Kim, John K; Inoki, Ken

    2017-06-26

    The RNA binding protein, LARP1, has been proposed to function downstream of mTORC1 to regulate the translation of 5'TOP mRNAs such as those encoding ribosome proteins (RP). However, the roles of LARP1 in the translation of 5'TOP mRNAs are controversial and its regulatory roles in mTORC1-mediated translation remain unclear. Here we show that LARP1 is a direct substrate of mTORC1 and Akt/S6K1. Deep sequencing of LARP1-bound mRNAs reveal that non-phosphorylated LARP1 interacts with both 5' and 3'UTRs of RP mRNAs and inhibits their translation. Importantly, phosphorylation of LARP1 by mTORC1 and Akt/S6K1 dissociates it from 5'UTRs and relieves its inhibitory activity on RP mRNA translation. Concomitantly, phosphorylated LARP1 scaffolds mTORC1 on the 3'UTRs of translationally-competent RP mRNAs to facilitate mTORC1-dependent induction of translation initiation. Thus, in response to cellular mTOR activity, LARP1 serves as a phosphorylation-sensitive molecular switch for turning off or on RP mRNA translation and subsequent ribosome biogenesis.

  17. Mammalian target of rapamycin complex 2 signaling pathway regulates transient receptor potential cation channel 6 in podocytes.

    Directory of Open Access Journals (Sweden)

    Fangrui Ding

    Full Text Available Transient receptor potential cation channel 6 (TRPC6 is a nonselective cation channel, and abnormal expression and gain of function of TRPC6 are involved in the pathogenesis of hereditary and nonhereditary forms of renal disease. Although the molecular mechanisms underlying these diseases remain poorly understood, recent investigations revealed that many signaling pathways are involved in regulating TRPC6. We aimed to examine the effect of the mammalian target of rapamycin (mTOR complex (mTOR complex 1 [mTORC1] or mTOR complex 2 [mTORC2] signaling pathways on TRPC6 in podocytes, which are highly terminally differentiated renal epithelial cells that are critically required for the maintenance of the glomerular filtration barrier. We applied both pharmacological inhibitors of mTOR and specific siRNAs against mTOR components to explore which mTOR signaling pathway is involved in the regulation of TRPC6 in podocytes. The podocytes were exposed to rapamycin, an inhibitor of mTORC1, and ku0063794, a dual inhibitor of mTORC1 and mTORC2. In addition, specific siRNA-mediated knockdown of the mTORC1 component raptor and the mTORC2 component rictor was employed. The TRPC6 mRNA and protein expression levels were examined via real-time quantitative PCR and Western blot, respectively. Additionally, fluorescence calcium imaging was performed to evaluate the function of TRPC6 in podocytes. Rapamycin displayed no effect on the TRPC6 mRNA or protein expression levels or TRPC6-dependent calcium influx in podocytes. However, ku0063794 down-regulated the TRPC6 mRNA and protein levels and suppressed TRPC6-dependent calcium influx in podocytes. Furthermore, knockdown of raptor did not affect TRPC6 expression or function, whereas rictor knockdown suppressed TRPC6 protein expression and TRPC6-dependent calcium influx in podocytes. These findings indicate that the mTORC2 signaling pathway regulates TRPC6 in podocytes but that the mTORC1 signaling pathway does not appear

  18. CD40 agonist converting CTL exhaustion via the activation of the mTORC1 pathway enhances PD-1 antagonist action in rescuing exhausted CTLs in chronic infection.

    Science.gov (United States)

    Xu, Aizhang; Wang, Rong; Freywald, Andrew; Stewart, Kristoffor; Tikoo, Suresh; Xu, Jianqing; Zheng, Changyu; Xiang, Jim

    2017-03-11

    Expansion of PD-1-expressing CD8 + cytotoxic T lymphocytes (CTLs) and associated CTL exhaustion are chief issues for ineffective virus-elimination in chronic infectious diseases. PD-1 blockade using antagonistic anti-PD-L1 antibodies results in a moderate conversion of CTL exhaustion. We previously demonstrated that CD40L signaling of ovalbumin (OVA)-specific vaccine, OVA-Texo, converts CTL exhaustion via the activation of the mTORC1 pathway in OVA-expressing adenovirus (AdVova)-infected B6 mice showing CTL inflation and exhaustion. Here, we developed AdVova-infected B6 and transgenic CD11c-DTR (termed AdVova-B6 and AdVova-CD11c-DTR) mice with chronic infection, and assessed a potential effect of CD40 agonist on the conversion of CTL exhaustion and on a potential enhancement of PD-1 antagonist action in rescuing exhausted CTLs in our chronic infection models. We demonstrate that a single dose of anti-CD40 alone can effectively convert CTL exhaustion by activating the mTORC1 pathway, leading to CTL proliferation, up-regulation of an effector-cytokine IFN-γ and the cytolytic effect in AdVova-B6 mice. Using anti-CD4 antibody and diphtheria toxin (DT) to deplete CD4 + T-cells and dendritic cells (DCs), we discovered that the CD40 agonist-induced conversion in AdVova-B6 and AdVova-CD11c-DTR mice is dependent upon host CD4 + T-cell and DC involvements. Moreover, CD40 agonist significantly enhances PD-1 antagonist effectiveness in rescuing exhausted CTLs in chronic infection. Taken together, our data demonstrate the importance of CD40 signaling in the conversion of CTL exhaustion and its ability to enhance PD-1 antagonist action in rescuing exhausted CTLs in chronic infection. Therefore, our findings may positively impact the design of new therapeutic strategies for chronic infectious diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Robust NMR water signal suppression for demanding analytical applications.

    Science.gov (United States)

    Aguilar, Juan A; Kenwright, Simon J

    2016-01-07

    We describe the design and application of robust, general-purpose water signal suppression pulse sequences well suited to chemometric work. Such pulse sequences need to deal well with pulse mis-calibrations, radiation damping, chemical exchange, and the presence of sample inhomogeneities, as well as with significant variations in sample characteristics such as pH, ionic strength, relaxation characteristics and molecular weight. Of course, such pulse sequences should produce un-distorted lineshapes and baselines and work well both under automation and in the hands of non-experts. As an example, one such pulse sequences, Robust-5, will be presented. This new pulse sequence meets those criteria and is able to reduce a 50 M proteo water signal down to a 0.9 mM level, without fine tuning, and under automation, and it is therefore well suited to the most demanding of analytical applications.

  20. Arctigenin functions as a selective agonist of estrogen receptor β to restrict mTORC1 activation and consequent Th17 differentiation.

    Science.gov (United States)

    Wu, Xin; Tong, Bei; Yang, Yan; Luo, Jinque; Yuan, Xusheng; Wei, Zhifeng; Yue, Mengfan; Xia, Yufeng; Dai, Yue

    2016-12-20

    Arctigenin was previously proven to inhibit Th17 cell differentiation and thereby attenuate colitis in mice by down-regulating the activation of mechanistic target of rapamycin complex 1 (mTORC1). The present study was performed to address its underlying mechanism in view of estrogen receptor (ER). The specific antagonist PHTPP or siRNA of ERβ largely diminished the inhibitory effect of arctigenin on the mTORC1 activation in T cell lines and primary CD4+ T cells under Th17-polarization condition, suggesting that arctigenin functioned in an ERβ-dependent manner. Moreover, arctigenin was recognized to be an agonist of ERβ, which could bind to ERβ with a moderate affinity, promote dissociation of ERβ/HSP90 complex and nuclear translocation and phosphorylation of ERβ, and increase the transcription activity. Following activation of ERβ, arctigenin inhibited the activity of mTORC1 by disruption of ERβ-raptor-mTOR complex assembly. Deficiency of ERβ markedly abolished arctigenin-mediated inhibition of Th17 cell differentiation. In colitis mice, the activation of ERβ, inhibition of mTORC1 activation and Th17 response by arctigenin were abolished by PHTPP treatment. In conclusion, ERβ might be the target protein of arctigenin responsible for inhibition of mTORC1 activation and resultant prevention of Th17 cell differentiation and colitis development.

  1. The E3 ubiquitin ligase ZNRF2 is a substrate of mTORC1 and regulates its activation by amino acids

    Science.gov (United States)

    Hoxhaj, Gerta; Caddye, Edward; Najafov, Ayaz; Houde, Vanessa P; Johnson, Catherine; Dissanayake, Kumara; Toth, Rachel; Campbell, David G; Prescott, Alan R; MacKintosh, Carol

    2016-01-01

    The mechanistic Target of Rapamycin complex 1 (mTORC1) senses intracellular amino acid levels through an intricate machinery, which includes the Rag GTPases, Ragulator and vacuolar ATPase (V-ATPase). The membrane-associated E3 ubiquitin ligase ZNRF2 is released into the cytosol upon its phosphorylation by Akt. In this study, we show that ZNRF2 interacts with mTOR on membranes, promoting the amino acid-stimulated translocation of mTORC1 to lysosomes and its activation in human cells. ZNRF2 also interacts with the V-ATPase and preserves lysosomal acidity. Moreover, knockdown of ZNRF2 decreases cell size and cell proliferation. Upon growth factor and amino acid stimulation, mTORC1 phosphorylates ZNRF2 on Ser145, and this phosphosite is dephosphorylated by protein phosphatase 6. Ser145 phosphorylation stimulates vesicle-to-cytosol translocation of ZNRF2 and forms a novel negative feedback on mTORC1. Our findings uncover ZNRF2 as a component of the amino acid sensing machinery that acts upstream of Rag-GTPases and the V-ATPase to activate mTORC1. DOI: http://dx.doi.org/10.7554/eLife.12278.001 PMID:27244671

  2. Suppression of probe background signals via B1 field inhomogeneity

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Jian; Reimer, Jeffrey

    2011-01-27

    A new approach combining a long pulse with the DEPTH sequence (Cory and Ritchey, Journal of Magnetic Resonance, 1988) greatly improves the efficiency for suppressing probe background signals arising from spinning modules. By applying a long initial excitation pulse in the DEPTH sequence, instead of a {pi}/2 pulse, the inhomogeneous B{sub 1} fields outside the coil can dephase the background coherence in the nutation frame. The initial long pulse and the following two consecutive EXORCYCLE {pi} pulses function complementarily and prove most effective in removing background signals from both strong and weak B{sub 1} fields. Experimentally, the length of the long pulse can be optimized around odd multiples of the {pi}/2 pulse, depending on the individual probe design, to preserve signals inside the coil while minimizing those from probe hardware. This method extends the applicability of the DEPTH sequence to probes with small differences in B{sub 1} field strength between the inside and outside of the coil, and can readily combine with well-developed double resonance experiments for quantitative measurement. In general, spin systems with weak internal interactions are required to attain efficient and uniform excitation for powder samples, and the principles to determine the applicability are discussed qualitatively in terms of the relative strength of spin interactions, r.f. power and spinning rate.

  3. TNF-{alpha} promotes human retinal pigment epithelial (RPE) cell migration by inducing matrix metallopeptidase 9 (MMP-9) expression through activation of Akt/mTORC1 signaling

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Cheng-hu; Cao, Guo-Fan [The Affiliated Eye Hospital of Nanjing Medical University, Nanjing 210029 (China); Jiang, Qin, E-mail: Jqin710@vip.sina.com [The Affiliated Eye Hospital of Nanjing Medical University, Nanjing 210029 (China); Yao, Jin, E-mail: dryaojin@yahoo.com [The Affiliated Eye Hospital of Nanjing Medical University, Nanjing 210029 (China)

    2012-08-17

    Highlights: Black-Right-Pointing-Pointer TNF-{alpha} induces MMP-9 expression and secretion to promote RPE cell migration. Black-Right-Pointing-Pointer MAPK activation is not critical for TNF-{alpha}-induced MMP-9 expression. Black-Right-Pointing-Pointer Akt and mTORC1 signaling mediate TNF-{alpha}-induced MMP-9 expression. Black-Right-Pointing-Pointer SIN1 knockdown showed no significant effect on MMP-9 expression by TNF-{alpha}. -- Abstract: Tumor necrosis factor-alpha (TNF-{alpha}) promotes in vitro retinal pigment epithelial (RPE) cell migration to initiate proliferative vitreoretinopathy (PVR). Here we report that TNF-{alpha} promotes human RPE cell migration by inducing matrix metallopeptidase 9 (MMP-9) expression. Inhibition of MMP-9 by its inhibitor or its neutralizing antibody inhibited TNF-{alpha}-induced in vitro RPE cell migration. Reversely, exogenously-added active MMP-9 promoted RPE cell migration. Suppression Akt/mTOR complex 1(mTORC1) activation by LY 294002 and rapamycin inhibited TNF-{alpha}-mediated MMP-9 expression. To introduce a constitutively active Akt (CA-Akt) in cultured RPE cells increased MMP-9 expression, and to block mTORC1 activation by rapamycin inhibited its effect. RNA interference (RNAi)-mediated silencing of SIN1, a key component of mTOR complex 2 (mTORC2), had no effect on MMP-9 expression or secretion. In conclusion, this study suggest that TNF-{alpha} promotes RPE cell migration by inducing MMP-9 expression through activation of Akt/ mTORC1, but not mTORC2 signaling.

  4. TNF-α promotes human retinal pigment epithelial (RPE) cell migration by inducing matrix metallopeptidase 9 (MMP-9) expression through activation of Akt/mTORC1 signaling

    International Nuclear Information System (INIS)

    Wang, Cheng-hu; Cao, Guo-Fan; Jiang, Qin; Yao, Jin

    2012-01-01

    Highlights: ► TNF-α induces MMP-9 expression and secretion to promote RPE cell migration. ► MAPK activation is not critical for TNF-α-induced MMP-9 expression. ► Akt and mTORC1 signaling mediate TNF-α-induced MMP-9 expression. ► SIN1 knockdown showed no significant effect on MMP-9 expression by TNF-α. -- Abstract: Tumor necrosis factor-alpha (TNF-α) promotes in vitro retinal pigment epithelial (RPE) cell migration to initiate proliferative vitreoretinopathy (PVR). Here we report that TNF-α promotes human RPE cell migration by inducing matrix metallopeptidase 9 (MMP-9) expression. Inhibition of MMP-9 by its inhibitor or its neutralizing antibody inhibited TNF-α-induced in vitro RPE cell migration. Reversely, exogenously-added active MMP-9 promoted RPE cell migration. Suppression Akt/mTOR complex 1(mTORC1) activation by LY 294002 and rapamycin inhibited TNF-α-mediated MMP-9 expression. To introduce a constitutively active Akt (CA-Akt) in cultured RPE cells increased MMP-9 expression, and to block mTORC1 activation by rapamycin inhibited its effect. RNA interference (RNAi)-mediated silencing of SIN1, a key component of mTOR complex 2 (mTORC2), had no effect on MMP-9 expression or secretion. In conclusion, this study suggest that TNF-α promotes RPE cell migration by inducing MMP-9 expression through activation of Akt/ mTORC1, but not mTORC2 signaling.

  5. Dual mTORC1/mTORC2 blocker as a possible therapy for tauopathy in cellular model.

    Science.gov (United States)

    Salama, Mohamed; Elhussiny, Mahmoud; Magdy, Alshimaa; Omran, Ahmed G; Alsayed, Aziza; Ashry, Ramy; Mohamed, Wael

    2017-10-27

    Tauopathy comprises a group of disorders caused by abnormal aggregates of tau protein. In these disorders phosphorylated tau protein tends to accumulate inside neuronal cells (soma) instead of the normal axonal distribution of tau. A suggested therapeutic strategy for tauopathy is to induce autophagy to increase the ability to get rid of the unwanted tau aggregates. One of the key controllers of autophagy is mTOR. Blocking mTOR leads to stimulation of autophagy. Recently, unravelling molecular structure of mTOR showed that it is formed of two subunits: mTORC1/C2. So, blocking both subunits of mTOR seems more attractive as it will explore all abilities of mTOR molecule. In the present study, we report using pp242 which is a dual mTORC1/C2 blocker in cellular model of tauopathy using LUHMES cell line. Adding fenazaquin to LUHMES cells induced tauopathy in the form of increased phospho tau aggregates. Moreover, fenazaquin treated cells showed the characteristic somatic redistribution of tau. PP242 use in the present tauopathy model reversed the pathology significantly without observable cellular toxicity for the used dosage of 1000 nM. The present study suggests the possible use of pp242 as a dual mTOR blocker to treat tauopathy.

  6. Arctigenin functions as a selective agonist of estrogen receptor ? to restrict mTORC1 activation and consequent Th17 differentiation

    OpenAIRE

    Wu, Xin; Tong, Bei; Yang, Yan; Luo, Jinque; Yuan, Xusheng; Wei, Zhifeng; Yue, Mengfan; Xia, Yufeng; Dai, Yue

    2016-01-01

    Arctigenin was previously proven to inhibit Th17 cell differentiation and thereby attenuate colitis in mice by down-regulating the activation of mechanistic target of rapamycin complex 1 (mTORC1). The present study was performed to address its underlying mechanism in view of estrogen receptor (ER). The specific antagonist PHTPP or siRNA of ER? largely diminished the inhibitory effect of arctigenin on the mTORC1 activation in T cell lines and primary CD4+ T cells under Th17-polarization condit...

  7. Phosphatidylcholine transfer protein interacts with thioesterase superfamily member 2 to attenuate insulin signaling.

    Science.gov (United States)

    Ersoy, Baran A; Tarun, Akansha; D'Aquino, Katharine; Hancer, Nancy J; Ukomadu, Chinweike; White, Morris F; Michel, Thomas; Manning, Brendan D; Cohen, David E

    2013-07-30

    Phosphatidylcholine transfer protein (PC-TP) is a phospholipid-binding protein that is enriched in liver and that interacts with thioesterase superfamily member 2 (THEM2). Mice lacking either protein exhibit improved hepatic glucose homeostasis and are resistant to diet-induced diabetes. Insulin receptor substrate 2 (IRS2) and mammalian target of rapamycin complex 1 (mTORC1) are key effectors of insulin signaling, which is attenuated in diabetes. We found that PC-TP inhibited IRS2, as evidenced by insulin-independent IRS2 activation after knockdown, genetic ablation, or chemical inhibition of PC-TP. In addition, IRS2 was activated after knockdown of THEM2, providing support for a role for the interaction of PC-TP with THEM2 in suppressing insulin signaling. Additionally, we showed that PC-TP bound to tuberous sclerosis complex 2 (TSC2) and stabilized the components of the TSC1-TSC2 complex, which functions to inhibit mTORC1. Preventing phosphatidylcholine from binding to PC-TP disrupted interactions of PC-TP with THEM2 and TSC2, and disruption of the PC-TP-THEM2 complex was associated with increased activation of both IRS2 and mTORC1. In livers of mice with genetic ablation of PC-TP or that had been treated with a PC-TP inhibitor, steady-state amounts of IRS2 were increased, whereas those of TSC2 were decreased. These findings reveal a phospholipid-dependent mechanism that suppresses insulin signaling downstream of its receptor.

  8. 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.

  9. Inhibition of mTORC1 Enhances the Translation of Chikungunya Proteins via the Activation of the MnK/eIF4E Pathway.

    Directory of Open Access Journals (Sweden)

    Pierre-Emmanuel Joubert

    2015-08-01

    Full Text Available Chikungunya virus (CHIKV, the causative agent of a major epidemic spanning five continents, is a positive stranded mRNA virus that replicates using the cell's cap-dependent translation machinery. Despite viral infection inhibiting mTOR, a metabolic sensor controls cap-dependent translation, viral proteins are efficiently translated. Rapalog treatment, silencing of mtor or raptor genes, but not rictor, further enhanced CHIKV infection in culture cells. Using biochemical assays and real time imaging, we demonstrate that this effect is independent of autophagy or type I interferon production. Providing in vivo evidence for the relevance of our findings, mice treated with mTORC1 inhibitors exhibited increased lethality and showed a higher sensitivity to CHIKV. A systematic evaluation of the viral life cycle indicated that inhibition of mTORC1 has a specific positive effect on viral proteins, enhancing viral replication by increasing the translation of both structural and nonstructural proteins. Molecular analysis defined a role for phosphatidylinositol-3 kinase (PI3K and MAP kinase-activated protein kinase (MnKs activation, leading to the hyper-phosphorylation of eIF4E. Finally, we demonstrated that in the context of CHIKV inhibition of mTORC1, viral replication is prioritized over host translation via a similar mechanism. Our study reveals an unexpected bypass pathway by which CHIKV protein translation overcomes viral induced mTORC1 inhibition.

  10. β-Carotene suppresses osteoclastogenesis and bone resorption by suppressing NF-κB signaling pathway.

    Science.gov (United States)

    Wang, Feng; Wang, Nan; Gao, Youshui; Zhou, Zubin; Liu, Wei; Pan, Chenhao; Yin, Peipei; Yu, Xiaowei; Tang, Mingjie

    2017-04-01

    β-Carotene is a natural anti-oxidant, which has been used for treatment of cancer and cardiovascular diseases. Recently, the ameliorating function of β-carotene in osteoporosis has been implicated. However, the precise mechanism of β-carotene in prevention and treatment of osteoporosis is largely unknown. In the present study, we aimed to elucidate how β-carotene affects osteoclast formation and bone resorption. Bone marrow-derived monocytes/-macrophages (BMM) were exposed to 0.05, 0.1, 0.2, 0.4 and 0.6μM β-carotene, followed by evaluation of cell viability, lactate dehydrogenase (LDH) release, receptor activator of nuclear factor kappa B ligand (RANKL)-induced osteoclastogenesis and resorption pits formation. Key factors in nuclear factor kappa B (NF-ĸB) and mitogen-activated protein kinases (MAPK) pathways were evaluated with western blot after BMM cells were exposed to RANKL and β-carotene. The effects of β-carotene in nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), c-Fos and cathepsin K (CTSK) expression were also evaluated. β-Carotene significantly inhibited BMM viability and promoted LDH release at concentrations of 0.4 and 0.6μM. A decrease in RANKL-induced osteoclastogenesis and resorption was also observed after β-carotene treatment. β-Carotene attenuated the NF-ĸB pathway activation by RANKL, with no effect on MAPK pathway. β-Carotene suppressed the upregulation of NFATc1 and c-Fos by RANKL. We clarified the anti-osteoclastogenic role of β-carotene, which is mediated by NF-κB signaling. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. WaterControl: self-diffusion based solvent signal suppression enhanced by selective inversion.

    Science.gov (United States)

    Zheng, Gang; Torres, Allan M; Price, William S

    2017-05-01

    Selective inversion/excitation based solvent signal suppression techniques are widely used in various NMR experiments because of their high efficiency and general applicability. However, these techniques generate a 'null'/suppression region containing (non-quantitatively) degraded solvent and desired resonances because of their reliance on the rejection of the coherence transfer pathway corresponding to all the resonances within the suppression region. To address this issue, the WaterControl technique was developed by inserting a (pulsed gradient - selective inversion pulse - pulsed gradient) unit into each 'transverse' period of a standard stimulated echo pulse sequence so that the coherence transfer pathways corresponding to both the suppression and non-suppression regions can be selected in one transient. The new sequence affords a diffusion based and quantifiable solvent signal suppression with no or minimal loss of features of interest. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  12. Suppression of Subsequent N1m Amplitude When the Masker Frequency is Different from the Signal

    Directory of Open Access Journals (Sweden)

    Yuka Uratani

    2014-01-01

    Full Text Available When two tones are presented in a short interval of time, the presentation of the preceding tone (masker suppresses the response evoked by the subsequent tone (signal. To address the processing in forward suppression, we applied 2- and 4-kHz maskers, followed by a 1-kHz signal at varying signal delays (0 to 320 ms and measured the signal-evoked N1m. A two-way analysis of variance revealed a statistically significant effect for signal delay in both masker presentation conditions. The N1m peak amplitude at the signal delay of 320 ms was significantly larger than those of 10, 20, 40, and 80 ms ( p < 0.05. No significant enhancement for the very short signal delay was observed. The results suggest that the enhancement of N1m peak amplitude for short signal delay conditions is maximized when the frequency of the masker is identical to that of the signal.

  13. Climbing fiber-evoked endocannabinoid signaling heterosynaptically suppresses presynaptic cerebellar long-term potentiation

    NARCIS (Netherlands)

    B.J. van Beugen (Boeke); R.Y. Nagaraja (Raghavendra); C.R.W. Hansel (Christian)

    2006-01-01

    textabstractEndocannabinoid signaling has been demonstrated to mediate depolarization-induced suppression of excitation at climbing fiber (CF) and parallel fiber (PF) synapses onto cerebellar Purkinje cells. Here, we show that CF-evoked release of cannabinoids (CBs) additionally suppresses a

  14. Oligodendrocyte precursor cell-intrinsic effect of Rheb1 controls differentiation and mediates mTORC1-dependent myelination in brain.

    Science.gov (United States)

    Zou, Yi; Jiang, Wanxiang; Wang, Jianqing; Li, Zhongping; Zhang, Junyan; Bu, Jicheng; Zou, Jia; Zhou, Liang; Yu, Shouyang; Cui, Yiyuan; Yang, Weiwei; Luo, Liping; Lu, Qing R; Liu, Yanhui; Chen, Mina; Worley, Paul F; Xiao, Bo

    2014-11-19

    Rheb1 is an immediate early gene that functions to activate mammalian target of rapamycin (mTor) selectively in complex 1 (mTORC1). We have demonstrated previously that Rheb1 is essential for myelination in the CNS using a Nestin-Cre driver line that deletes Rheb1 in all neural cell lineages, and recent studies using oligodendrocyte-specific CNP-Cre have suggested a preferential role for mTORC1 is myelination in the spinal cord. Here, we examine the role of Rheb1/mTORC1 in mouse oligodendrocyte lineage using separate Cre drivers for oligodendrocyte progenitor cells (OPCs) including Olig1-Cre and Olig2-Cre as well as differentiated and mature oligodendrocytes including CNP-Cre and Tmem10-Cre. Deletion of Rheb1 in OPCs impairs their differentiation to mature oligodendrocytes. This is accompanied by reduced OPC cell-cycle exit suggesting a requirement for Rheb1 in OPC differentiation. The effect of Rheb1 on OPC differentiation is mediated by mTor since Olig1-Cre deletion of mTor phenocopies Olig1-Cre Rheb1 deletion. Deletion of Rheb1 in mature oligodendrocytes, in contrast, does not disrupt developmental myelination or myelin maintenance. Loss of Rheb1 in OPCs or neural progenitors does not affect astrocyte formation in gray and white matter, as indicated by the pan-astrocyte marker Aldh1L1. We conclude that OPC-intrinsic mTORC1 activity mediated by Rheb1 is critical for differentiation of OPCs to mature oligodendrocytes, but that mature oligodendrocytes do not require Rheb1 to make myelin or maintain it in the adult brain. These studies reveal mechanisms that may be relevant for both developmental myelination and impaired remyelination in myelin disease. Copyright © 2014 the authors 0270-6474/14/3415764-15$15.00/0.

  15. Kalman filtering to suppress spurious signals in Adaptive Optics control

    Energy Technology Data Exchange (ETDEWEB)

    Poyneer, L; Veran, J P

    2010-03-29

    In many scenarios, an Adaptive Optics (AO) control system operates in the presence of temporally non-white noise. We use a Kalman filter with a state space formulation that allows suppression of this colored noise, hence improving residual error over the case where the noise is assumed to be white. We demonstrate the effectiveness of this new filter in the case of the estimated Gemini Planet Imager tip-tilt environment, where there are both common-path and non-common path vibrations. We discuss how this same framework can also be used to suppress spatial aliasing during predictive wavefront control assuming frozen flow in a low-order AO system without a spatially filtered wavefront sensor, and present experimental measurements from Altair that clearly reveal these aliased components.

  16. The Antipancreatic Cancer Activity of OSI-027, a Potent and Selective Inhibitor of mTORC1 and mTORC2.

    Science.gov (United States)

    Chen, Bo; Xu, Ming; Zhang, Hui; Xu, Ming-zheng; Wang, Xu-jing; Tang, Qing-he; Tang, Jian-ying

    2015-10-01

    In the present study, we investigated the potential activity of OSI-027, a potent and selective mammalian target of rapamycin (mTOR) complex 1/2 (mTORC1/2) dual inhibitor, against pancreatic cancer cells both in vitro and in vivo. We demonstrated that OSI-027 inhibited survival and growth of both primary and transformed (PANC-1 and MIA PaCa-2 lines) human pancreatic cancer cells. Meanwhile, OSI-027 induced caspase-dependent apoptotic death of the pancreatic cancer cells. On the other hand, caspase inhibitors alleviated cytotoxicity by OSI-027. At the molecular level, OSI-027 treatment blocked mTORC1 and mTORC2 activation simultaneously, without affecting ERK-mitogen-activated protein kinase activation. Importantly, OSI-027 activated cytoprotective autophagy in the above cancer cells. Whereas pharmacological blockage of autophagy or siRNA knockdown of Beclin-1 significantly enhanced the OSI-027-induced activity against pancreatic cancer cells. Specifically, a relatively low dose of OSI-027 sensitized gemcitabine-induced pancreatic cancer cell death in vitro. Further, administration of OSI-027 or together with gemcitabine dramatically inhibited PANC-1 xenograft growth in severe combined immunodeficiency mice, leading to significant mice survival improvement. In summary, the preclinical results of this study suggest that targeting mTORC1/2 synchronously by OSI-027 could be further investigated as a valuable treatment for pancreatic cancer.

  17. Repletion of branched chain amino acids reverses mTORC1 signaling but not improved metabolism during dietary protein dilution

    DEFF Research Database (Denmark)

    Maida, Adriano; Chan, Jessica S K; Sjøberg, Kim Anker

    2017-01-01

    OBJECTIVE: Dietary protein dilution (PD) has been associated with metabolic advantages such as improved glucose homeostasis and increased energy expenditure. This phenotype involves liver-induced release of FGF21 in response to amino acid insufficiency; however, it has remained unclear whether di...

  18. CD137 signaling suppresses the suppressive function of treg cells of peripheral blood from breast cancer patients

    International Nuclear Information System (INIS)

    Lu Tian; Jiang Linhua; ZZhang Chi; Sun Xuewei; Ju Songguang

    2009-01-01

    Objective: To explore the biological effect of CD137 and its molecular mechanism on CD4 + CD25 + Treg cells. Methods: Anti-CD137 mAb was added to stimulate the T cells that isolated from peripheral blood of breast cancer patients and activated by PHA. T cell proliferation was determined by cell counting or by 3 H-TdR incorporation assessing at the 3rd. The phenotype of cells was determined by FACS, and Foxp3 analysis was performed after fixation and intracellular staining. Cytokine in the supernatant was quantified with ELISA. Results: CD137 expressed on CD4 + CD25 + Treg cells. Triggering CD137 signaling of CD4 + CD25 + Treg cells by anti-CD137 mAb could promote the proliferation of T cells form PBMCs of breast cancer patients and decrease the ratio of Foxp3 + Treg population and reduce Foxp3 expression of Treg cells, as well as the production of TGF-β1 and IL-10, and suppress the ability of Treg cells to inhibit proliferation of CD4 + CD25 - T cells. Conclusion: CD137 signaling could suppress the suppressive function of Treg cells, and CD137 might be a potential molecular target for the immunological interference. (authors)

  19. G(i)α proteins exhibit functional differences in the activation of ERK1/2, Akt and mTORC1 by growth factors in normal and breast cancer cells.

    Science.gov (United States)

    Wang, Zhanwei; Dela Cruz, Rica; Ji, Fang; Guo, Sheng; Zhang, Jianhua; Wang, Ying; Feng, Gen-Sheng; Birnbaumer, Lutz; Jiang, Meisheng; Chu, Wen-Ming

    2014-02-13

    In a classic model, G(i)α proteins including G(i1)α, G(i2)α and G(i3)α are important for transducing signals from G(i)α protein-coupled receptors (G(i)αPCRs) to their downstream cascades in response to hormones and neurotransmitters. Our previous study has suggested that G(i1)α, G(i2)α and G(i3)α are also important for the activation of the PI3K/Akt/mTORC1 pathway by epidermal growth factor (EGF) and its family members. However, a genetic role of these G(i)α proteins in the activation of extracellular signal-regulated protein kinase 1 and 2 (ERK1/2) by EGF is largely unknown. Further, it is not clear whether these G(i)α proteins are also engaged in the activation of both the Akt/mTORC1 and ERK1/2 pathways by other growth factor family members. Additionally, a role of these G(i)α proteins in breast cancer remains to be elucidated. We found that Gi1/3 deficient MEFs with the low expression level of G(i2)α showed defective ERK1/2 activation by EGFs, IGF-1 and insulin, and Akt and mTORC1 activation by EGFs and FGFs. Gi1/2/3 knockdown breast cancer cells exhibited a similar defect in the activations and a defect in in vitro growth and invasion. The G(i)α proteins associated with RTKs, Gab1, FRS2 and Shp2 in breast cancer cells and their ablation impaired Gab1's interactions with Shp2 in response to EGF and IGF-1, or with FRS2 and Grb2 in response to bFGF. G(i)α proteins differentially regulate the activation of Akt, mTORC1 and ERK1/2 by different families of growth factors. G(i)α proteins are important for breast cancer cell growth and invasion.

  20. Cuckoo search based optimal mask generation for noise suppression and enhancement of speech signal

    Directory of Open Access Journals (Sweden)

    Anil Garg

    2015-07-01

    Full Text Available In this paper, an effective noise suppression technique for enhancement of speech signals using optimized mask is proposed. Initially, the noisy speech signal is broken down into various time–frequency (TF units and the features are extracted by finding out the Amplitude Magnitude Spectrogram (AMS. The signals are then classified based on quality ratio into different classes to generate the initial set of solutions. Subsequently, the optimal mask for each class is generated based on Cuckoo search algorithm. Subsequently, in the waveform synthesis stage, filtered waveforms are windowed and then multiplied by the optimal mask value and summed up to get the enhanced target signal. The experimentation of the proposed technique was carried out using various datasets and the performance is compared with the previous techniques using SNR. The results obtained proved the effectiveness of the proposed technique and its ability to suppress noise and enhance the speech signal.

  1. The dual mTORC1 and mTORC2 inhibitor AZD8055 inhibits head and neck squamous cell carcinoma cell growth in vivo and in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qiang; Song, Xin-mao; Ji, Yang-yang; Jiang, Hui; Xu, Lin-gen, E-mail: drlingenxu@126.com

    2013-11-01

    Highlights: •AZD8055 induces significant cytotoxic effects in cultured HNSCC cells. •AZD8055 blocks mTORC1 and mTORC2 activation in cultured HNSCC cells. •JNK activation is required for AZD8055-induced HNSCC cell death. •AZD8055 inhibits Hep-2 cell growth in vivo, and was more efficient than rapamycin. -- Abstract: The serine/threonine kinase mammalian target of rapamycin (mTOR) promotes cell survival and proliferation, and is constitutively activated in head and neck squamous cell carcinoma (HNSCC). Thus mTOR is an important target for drug development in this disease. Here we tested the anti-tumor ability of AZD8055, the novel mTOR inhibitor, in HNSCC cells. AZD8055 induced dramatic cell death of HNSCC lines (Hep-2 and SCC-9) through autophagy. AZD8055 blocked both mTOR complex (mTORC) 1 and mTORC2 activation without affecting Erk in cultured HNSCC cells. Meanwhile, AZD8055 induced significant c-Jun N-terminal kinase (JNK) activation, which was also required for cancer cell death. JNK inhibition by its inhibitors (SP 600125 and JNK-IN-8), or by RNA interference (RNAi) alleviated AZD8055-induced cell death. Finally, AZD8055 markedly increased the survival of Hep-2 transplanted mice through a significant reduction of tumor growth, without apparent toxicity, and its anti-tumor ability was more potent than rapamycin. Meanwhile, AZD8055 administration activated JNK while blocking mTORC1/2 in Hep-2 tumor engrafts. Our current results strongly suggest that AZD8055 may be further investigated for HNSCC treatment in clinical trials.

  2. A first in man, dose-finding study of the mTORC1/mTORC2 inhibitor OSI-027 in patients with advanced solid malignancies.

    Science.gov (United States)

    Mateo, Joaquin; Olmos, David; Dumez, Herlinde; Poondru, Srinivasu; Samberg, Nancy L; Barr, Sharon; Van Tornout, Jan M; Jie, Fei; Sandhu, Shahneen; Tan, Daniel S; Moreno, Victor; LoRusso, Patricia M; Kaye, Stan B; Schöffski, Patrick

    2016-04-12

    The kinase activity of mTOR involves 2 multiprotein complexes, (mTORC1-mTORC2). Targeting mTORC1 with rapalogues induces compensatory feedback loops resulting in AKT/ERK activation, which may be abrogated by mTORC2 inhibition. A first-in-human trial evaluating tolerability, pharmacokinetics and pharmacodynamics of the dual TORC1/TORC2 inhibitor OSI-027 was conducted. Dose escalation was pursued for three schedules of administration (three consecutive days per week (S1), once a week (S2) and daily dosing (S3)), until dose-limiting toxicities (DLT) were identified. Expansion cohorts with paired tumour biopsies were initiated based on tolerability and pharmacodynamics. One hundred and twenty eight patients with advanced cancer were enrolled. DLT consisted predominantly of fatigue, renal function disturbances and cardiac events. OSI-027 exposure was dose proportional, with Tmax within 4 h and a half-life of ∼14 h. Expansion cohorts were initiated for S1 and S2, as MTD for S3 was overall considered suboptimal. Target modulation in peripheral blood mononuclear cells were observed from 30 mg, but in tumour biopsies 120 mg QD were needed, which was a non-tolerable dose due to renal toxicity. No RECIST responses were recorded, with stable disease >6 months in six (5%) patients. OSI-027 inhibits mTORC1/2 in patients with advanced tumour s in a dose-dependent manner but doses above the tolerable levels in S1 and S3 are required for a sustained biological effect in tumour biopsies.

  3. SIRT1 activator (SRT1720) improves the follicle reserve and prolongs the ovarian lifespan of diet-induced obesity in female mice via activating SIRT1 and suppressing mTOR signaling.

    Science.gov (United States)

    Zhou, Xiao-Ling; Xu, Jin-Jie; Ni, Yan-Hong; Chen, Xiao-Chun; Zhang, Hong-Xia; Zhang, Xing-Mei; Liu, Wei-Juan; Luo, Li-Li; Fu, Yu-Cai

    2014-10-21

    SRT1720 may improve the follicle pool reserve in HF diet-induced obese female mice via activating SIRT1 signaling and suppressing mTOR signaling, thus extending the ovarian lifespan.

  4. Ligand-Occupied Integrin Internalization Links Nutrient Signaling to Invasive Migration

    Directory of Open Access Journals (Sweden)

    Elena Rainero

    2015-01-01

    Full Text Available Integrin trafficking is key to cell migration, but little is known about the spatiotemporal organization of integrin endocytosis. Here, we show that α5β1 integrin undergoes tensin-dependent centripetal movement from the cell periphery to populate adhesions located under the nucleus. From here, ligand-engaged α5β1 integrins are internalized under control of the Arf subfamily GTPase, Arf4, and are trafficked to nearby late endosomes/lysosomes. Suppression of centripetal movement or Arf4-dependent endocytosis disrupts flow of ligand-bound integrins to late endosomes/lysosomes and their degradation within this compartment. Arf4-dependent integrin internalization is required for proper lysosome positioning and for recruitment and activation of mTOR at this cellular subcompartment. Furthermore, nutrient depletion promotes subnuclear accumulation and endocytosis of ligand-engaged α5β1 integrins via inhibition of mTORC1. This two-way regulatory interaction between mTORC1 and integrin trafficking in combination with data describing a role for tensin in invasive cell migration indicate interesting links between nutrient signaling and metastasis.

  5. A comprehensive siRNA screen for kinases that suppress macroautophagy in optimal growth conditions

    DEFF Research Database (Denmark)

    Szyniarowski, Piotr; Corcelle-Termeau, Elisabeth; Farkas, Thomas

    2011-01-01

    , whereas CSNK1A1, BUB1, PKLR and NEK4 suppressed autophagosome formation downstream or independent of mTORC1. Importantly, all identified kinases except for BUB1 regulated macroautophagy also in immortalized MCF-10A breast epithelial cells. The kinases identified here shed light to the complex regulation...

  6. Kurarinol induces hepatocellular carcinoma cell apoptosis through suppressing cellular signal transducer and activator of transcription 3 signaling

    Energy Technology Data Exchange (ETDEWEB)

    Shu, Guangwen; Yang, Jing; Zhao, Wenhao; Xu, Chan; Hong, Zongguo; Mei, Zhinan; Yang, Xinzhou, E-mail: xinzhou_yang@hotmail.com

    2014-12-01

    Kurarinol is a flavonoid isolated from roots of the medical plant Sophora flavescens. However, its cytotoxic activity against hepatocellular carcinoma (HCC) cells and toxic effects on mammalians remain largely unexplored. Here, the pro-apoptotic activities of kurarinol on HCC cells and its toxic impacts on tumor-bearing mice were evaluated. The molecular mechanisms underlying kurarinol-induced HCC cell apoptosis were also investigated. We found that kurarinol dose-dependently provoked HepG2, Huh-7 and H22 HCC cell apoptosis. In addition, kurarinol gave rise to a considerable decrease in the transcriptional activity of signal transducer and activator of transcription 3 (STAT3) in HCC cells. Suppression of STAT3 signaling is involved in kurarinol-induced HCC cell apoptosis. In vivo studies showed that kurarinol injection substantially induced transplanted H22 cell apoptosis with low toxic impacts on tumor-bearing mice. Similarly, the transcriptional activity of STAT3 in transplanted tumor tissues was significantly suppressed after kurarinol treatment. Collectively, our current research demonstrated that kurarinol has the capacity of inducing HCC cell apoptosis both in vitro and in vivo with undetectable toxic impacts on the host. Suppressing STAT3 signaling is implicated in kurarinol-mediated HCC cell apoptosis. - Highlights: • Kurarinol induces hepatocellular carcinoma (HCC) cell apoptosis. • Kurarinol induces HCC cell apoptosis via inhibiting STAT3. • Kurarinol exhibits low toxic effects on tumor-bearing animals.

  7. Kurarinol induces hepatocellular carcinoma cell apoptosis through suppressing cellular signal transducer and activator of transcription 3 signaling

    International Nuclear Information System (INIS)

    Shu, Guangwen; Yang, Jing; Zhao, Wenhao; Xu, Chan; Hong, Zongguo; Mei, Zhinan; Yang, Xinzhou

    2014-01-01

    Kurarinol is a flavonoid isolated from roots of the medical plant Sophora flavescens. However, its cytotoxic activity against hepatocellular carcinoma (HCC) cells and toxic effects on mammalians remain largely unexplored. Here, the pro-apoptotic activities of kurarinol on HCC cells and its toxic impacts on tumor-bearing mice were evaluated. The molecular mechanisms underlying kurarinol-induced HCC cell apoptosis were also investigated. We found that kurarinol dose-dependently provoked HepG2, Huh-7 and H22 HCC cell apoptosis. In addition, kurarinol gave rise to a considerable decrease in the transcriptional activity of signal transducer and activator of transcription 3 (STAT3) in HCC cells. Suppression of STAT3 signaling is involved in kurarinol-induced HCC cell apoptosis. In vivo studies showed that kurarinol injection substantially induced transplanted H22 cell apoptosis with low toxic impacts on tumor-bearing mice. Similarly, the transcriptional activity of STAT3 in transplanted tumor tissues was significantly suppressed after kurarinol treatment. Collectively, our current research demonstrated that kurarinol has the capacity of inducing HCC cell apoptosis both in vitro and in vivo with undetectable toxic impacts on the host. Suppressing STAT3 signaling is implicated in kurarinol-mediated HCC cell apoptosis. - Highlights: • Kurarinol induces hepatocellular carcinoma (HCC) cell apoptosis. • Kurarinol induces HCC cell apoptosis via inhibiting STAT3. • Kurarinol exhibits low toxic effects on tumor-bearing animals

  8. Schisantherin A suppresses osteoclast formation and wear particle-induced osteolysis via modulating RANKL signaling pathways

    Energy Technology Data Exchange (ETDEWEB)

    He, Yi; Zhang, Qing; Shen, Yi; Chen, Xia; Zhou, Feng; Peng, Dan, E-mail: xyeypd@163.com

    2014-07-04

    Highlights: • Schisantherin A suppresses osteoclasts formation and function in vitro. • Schisantherin A impairs RANKL signaling pathway. • Schisantherin A suppresses osteolysis in vivo. • Schisantherin A may be used for treating osteoclast related diseases. - Abstract: Receptor activator of NF-κB ligand (RANKL) plays critical role in osteoclastogenesis. Targeting RANKL signaling pathways has been a promising strategy for treating osteoclast related bone diseases such as osteoporosis and aseptic prosthetic loosening. Schisantherin A (SA), a dibenzocyclooctadiene lignan isolated from the fruit of Schisandra sphenanthera, has been used as an antitussive, tonic, and sedative agent, but its effect on osteoclasts has been hitherto unknown. In the present study, SA was found to inhibit RANKL-induced osteoclast formation and bone resorption. The osteoclastic specific marker genes induced by RANKL including c-Src, SA inhibited OSCAR, cathepsin K and TRAP in a dose dependent manner. Further signal transduction studies revealed that SA down-regulate RANKL-induced nuclear factor-kappaB (NF-κB) signaling activation by suppressing the phosphorylation and degradation of IκBα, and subsequently preventing the NF-κB transcriptional activity. Moreover, SA also decreased the RANKL-induced MAPKs signaling pathway, including JNK and ERK1/2 posphorylation while had no obvious effects on p38 activation. Finally, SA suppressed the NF-κB and MAPKs subsequent gene expression of NFATc1 and c-Fos. In vivo studies, SA inhibited osteoclast function and exhibited bone protection effect in wear-particle-induced bone erosion model. Taken together, SA could attenuate osteoclast formation and wear particle-induced osteolysis by mediating RANKL signaling pathways. These data indicated that SA is a promising therapeutic natural compound for the treatment of osteoclast-related prosthesis loosening.

  9. Schisantherin A suppresses osteoclast formation and wear particle-induced osteolysis via modulating RANKL signaling pathways

    International Nuclear Information System (INIS)

    He, Yi; Zhang, Qing; Shen, Yi; Chen, Xia; Zhou, Feng; Peng, Dan

    2014-01-01

    Highlights: • Schisantherin A suppresses osteoclasts formation and function in vitro. • Schisantherin A impairs RANKL signaling pathway. • Schisantherin A suppresses osteolysis in vivo. • Schisantherin A may be used for treating osteoclast related diseases. - Abstract: Receptor activator of NF-κB ligand (RANKL) plays critical role in osteoclastogenesis. Targeting RANKL signaling pathways has been a promising strategy for treating osteoclast related bone diseases such as osteoporosis and aseptic prosthetic loosening. Schisantherin A (SA), a dibenzocyclooctadiene lignan isolated from the fruit of Schisandra sphenanthera, has been used as an antitussive, tonic, and sedative agent, but its effect on osteoclasts has been hitherto unknown. In the present study, SA was found to inhibit RANKL-induced osteoclast formation and bone resorption. The osteoclastic specific marker genes induced by RANKL including c-Src, SA inhibited OSCAR, cathepsin K and TRAP in a dose dependent manner. Further signal transduction studies revealed that SA down-regulate RANKL-induced nuclear factor-kappaB (NF-κB) signaling activation by suppressing the phosphorylation and degradation of IκBα, and subsequently preventing the NF-κB transcriptional activity. Moreover, SA also decreased the RANKL-induced MAPKs signaling pathway, including JNK and ERK1/2 posphorylation while had no obvious effects on p38 activation. Finally, SA suppressed the NF-κB and MAPKs subsequent gene expression of NFATc1 and c-Fos. In vivo studies, SA inhibited osteoclast function and exhibited bone protection effect in wear-particle-induced bone erosion model. Taken together, SA could attenuate osteoclast formation and wear particle-induced osteolysis by mediating RANKL signaling pathways. These data indicated that SA is a promising therapeutic natural compound for the treatment of osteoclast-related prosthesis loosening

  10. Improving Multi Access Interference Suppression in Optical CDMA by using all-Optical Signal Processing

    Directory of Open Access Journals (Sweden)

    T. B. Osadola

    2013-06-01

    Full Text Available This paper presents the study of a novel all-optical method for processing optical CDMA signals towards improving suppression of multi access interference. The main focus is on incoherent OCDMA systems using multiwavelength 2D-WH/TS codes generated using FBG based encoders and decoders. The MAI suppression capabilities based on its ability to eliminate selective wavelength pulse processing have been shown. A novel transmitter architecture that achieves up to 3dB power saving was also presented. As a result of hardware savings, processing cost will be significantly reduced and power budget improvement resulted in improved performance.

  11. Suppression of choriocarcinoma invasion and metastasis following blockade of BDNF/TrkB signaling

    International Nuclear Information System (INIS)

    Kawamura, Kazuhiro; Kawamura, Nanami; Okamoto, Naoki; Manabe, Motomu

    2013-01-01

    Brain-derived neurotrophic factor (BDNF) acts through its cognate receptor tyrosine kinase-B (TrkB) to regulate diverse physiological functions in reproductive and other tissues. In normal and malignant trophoblastic cells, the BDNF/TrkB signaling promotes cell growth. Due to the highly malignant nature of choriocarcinoma, we investigated possible involvement of this system in choriocarcinoma cell invasion and metastasis. We demonstrated that treatment of cultured choriocarcinoma cells, known to express both BDNF and TrkB, with a soluble TrkB ectodomain or a Trk receptor inhibitor K252a suppressed cell invasion accompanied with decreased expression of matrix metalloproteinase-2, a cell invasion marker. In vivo studies using a tumor xenograft model in athymic nude mice further showed inhibition of cell invasion from tumors to surrounding tissues following the suppression of endogenous TrkB signaling. For an in vivo model of choriocarcinoma metastasis, we performed intravenous injections of JAR cells expressing firefly luciferase into severe combined immunodeficiency (SCID) mice. Treatment with K252a inhibited metastasis of tumors to distant organs. In vivo K252a treatment also suppressed metastatic tumor growth as reflected by decreased cell proliferation and increased apoptosis and caspases-3/7 activities, together with reduced tissue levels of a tumor marker, human chorionic gonadotropin-β. In vivo suppression of TrkB signaling also led to decreased expression of angiogenic markers in metastatic tumor, including cluster of differentiation 31 and vascular endothelial growth factor A. Our findings suggested essential autocrine/paracrine roles of the BDNF/TrkB signaling system in choriocarcinoma invasion and metastasis. Inhibition of this signaling could serve as the basis to develop a novel therapy for patients with choriocarcinoma

  12. FGF signaling sustains the odontogenic fate of dental mesenchyme by suppressing β-catenin signaling.

    Science.gov (United States)

    Liu, Chao; Gu, Shuping; Sun, Cheng; Ye, Wenduo; Song, Zhongchen; Zhang, Yanding; Chen, YiPing

    2013-11-01

    Odontoblasts and osteoblasts develop from multipotent craniofacial neural crest cells during tooth and jawbone development, but the mechanisms that specify and sustain their respective fates remain largely unknown. In this study we used early mouse molar and incisor tooth germs that possess distinct tooth-forming capability after dissociation and reaggregation in vitro to investigate the mechanism that sustains odontogenic fate of dental mesenchyme during tooth development. We found that after dissociation and reaggregation, incisor, but not molar, mesenchyme exhibits a strong osteogenic potency associated with robustly elevated β-catenin signaling activity in a cell-autonomous manner, leading to failed tooth formation in the reaggregates. Application of FGF3 to incisor reaggregates inhibits β-catenin signaling activity and rescues tooth formation. The lack of FGF retention on the cell surface of incisor mesenchyme appears to account for the differential osteogenic potency between incisor and molar, which can be further attributed to the differential expression of syndecan 1 and NDST genes. We further demonstrate that FGF signaling inhibits intracellular β-catenin signaling by activating the PI3K/Akt pathway to regulate the subcellular localization of active GSK3β in dental mesenchymal cells. Our results reveal a novel function for FGF signaling in ensuring the proper fate of dental mesenchyme by regulating β-catenin signaling activity during tooth development.

  13. miR-612 suppresses the stemness of liver cancer via Wnt/β-catenin signaling

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Jun [Liver Cancer Institute and Zhongshan Hospital, Fudan University, Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Shanghai 200032 (China); Tao, Zhong-Hua [Department of Medical Oncology, Shanghai Cancer Center, Fudan University, Shanghai 200032 (China); Wen, Duo; Wan, Jin-Liang; Liu, Dong-Li; Zhang, Shu; Cui, Jie-Feng; Sun, Hui-Chuan; Wang, Lu [Liver Cancer Institute and Zhongshan Hospital, Fudan University, Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Shanghai 200032 (China); Zhou, Jian; Fan, Jia [Liver Cancer Institute and Zhongshan Hospital, Fudan University, Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Shanghai 200032 (China); Institute of Biomedical Sciences of Fudan University, Shanghai 200032 (China); Wu, Wei-Zhong, E-mail: wu.weizhong@zs-hospital.sh.cn [Liver Cancer Institute and Zhongshan Hospital, Fudan University, Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Shanghai 200032 (China)

    2014-04-25

    Highlights: • miR-612 suppresses tumorsphere and clone formation of HCC cells. • miR-612 reduces drug resistance of HCC cells. • miR-612 suppresses tumorigenesis of HCC in NOD/SCID mice. • miR-612 inhibits an invasive frontier of HCC xenografts. • miR-612 suppresses Wnt/β-catenin signaling. - Abstract: Previous research showed that microRNA-612 (miR-612) has inhibitory effects on cell proliferation, migration, invasion, and metastasis of hepatocellular carcinoma (HCC). AKT2 was confirmed to be a direct target of miR-612, through which the epithelial–mesenchymal transition (EMT) and metastasis of HCC were inhibited. Our present findings reveal that miR-612 is able to suppress the stemness of HCC by reducing the number and size of tumorspheres as well as clone formation in soft agar, and to relieve drug resistance to cisplatin and 5-fluorouracil. In addition, miR-612 hampered the capacity of tumorigenesis in NOD/SCID mice and redistributed the tumor invasive frontier of miR-612-modulating cells. Finally, our findings suggest that Wnt/β-catenin signaling is required in the regulation of EMT-associated stem cell-like traits by miR-612.

  14. Salidroside Suppresses HUVECs Cell Injury Induced by Oxidative Stress through Activating the Nrf2 Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Yao Zhu

    2016-08-01

    Full Text Available Oxidative stress plays an important role in the pathogenesis of cardiovascular diseases. Salidroside (SAL, one of the main effective constituents of Rhodiola rosea, has been reported to suppress oxidative stress-induced cardiomyocyte injury and necrosis by promoting transcription of nuclear factor E2-related factor 2 (Nrf2-regulated genes such as heme oxygenase-1 (HO-1 and NAD(PH dehydrogenase (quinone1 (NQO1. However, it has not been indicated whether SAL might ameliorate endothelial injury induced by oxidative stress. Here, our study demonstrated that SAL might suppress HUVEC cell injury induced by oxidative stress through activating the Nrf2 signaling pathway. The results of our study indicated that SAL decreased the levels of intercellular reactive oxygen species (ROS and malondialdehyde (MDA, and improved the activities of superoxide dismutase (SOD and catalase (CAT, resulting in protective effects against oxidative stress-induced cell damage in HUVECs. It suppressed oxidative stress damage by inducing Nrf2 nuclear translocation and activating the expression of Nrf2-regulated antioxidant enzyme genes such as HO-1 and NQO1 in HUVECs. Knockdown of Nrf2 with siRNA abolished the cytoprotective effects against oxidative stress, decreased the expression of Nrf2, HO-1, and NQO1, and inhibited the nucleus translocation of Nrf2 in HUVECs. This study is the first to demonstrate that SAL suppresses HUVECs cell injury induced by oxidative stress through activating the Nrf2 signaling pathway.

  15. miR-612 suppresses the stemness of liver cancer via Wnt/β-catenin signaling

    International Nuclear Information System (INIS)

    Tang, Jun; Tao, Zhong-Hua; Wen, Duo; Wan, Jin-Liang; Liu, Dong-Li; Zhang, Shu; Cui, Jie-Feng; Sun, Hui-Chuan; Wang, Lu; Zhou, Jian; Fan, Jia; Wu, Wei-Zhong

    2014-01-01

    Highlights: • miR-612 suppresses tumorsphere and clone formation of HCC cells. • miR-612 reduces drug resistance of HCC cells. • miR-612 suppresses tumorigenesis of HCC in NOD/SCID mice. • miR-612 inhibits an invasive frontier of HCC xenografts. • miR-612 suppresses Wnt/β-catenin signaling. - Abstract: Previous research showed that microRNA-612 (miR-612) has inhibitory effects on cell proliferation, migration, invasion, and metastasis of hepatocellular carcinoma (HCC). AKT2 was confirmed to be a direct target of miR-612, through which the epithelial–mesenchymal transition (EMT) and metastasis of HCC were inhibited. Our present findings reveal that miR-612 is able to suppress the stemness of HCC by reducing the number and size of tumorspheres as well as clone formation in soft agar, and to relieve drug resistance to cisplatin and 5-fluorouracil. In addition, miR-612 hampered the capacity of tumorigenesis in NOD/SCID mice and redistributed the tumor invasive frontier of miR-612-modulating cells. Finally, our findings suggest that Wnt/β-catenin signaling is required in the regulation of EMT-associated stem cell-like traits by miR-612

  16. Food restriction increase the expression of mTORC1 complex genes in the skeletal muscle of juvenile pacu (Piaractus mesopotamicus)

    Science.gov (United States)

    de Paula, Tassiana Gutierrez; Zanella, Bruna Tereza Thomazini; Fantinatti, Bruno Evaristo de Almeida; de Moraes, Leonardo Nazário; Duran, Bruno Oliveira da Silva; de Oliveira, Caroline Bredariol; Salomão, Rondinelle Artur Simões; da Silva, Rafaela Nunes; Padovani, Carlos Roberto; dos Santos, Vander Bruno; Mareco, Edson Assunção; Carvalho, Robson Francisco; Dal-Pai-Silva, Maeli

    2017-01-01

    Skeletal muscle is capable of phenotypic adaptation to environmental factors, such as nutrient availability, by altering the balance between muscle catabolism and anabolism that in turn coordinates muscle growth. Small noncoding RNAs, known as microRNAs (miRNAs), repress the expression of target mRNAs, and many studies have demonstrated that miRNAs regulate the mRNAs of catabolic and anabolic genes. We evaluated muscle morphology, gene expression of components involved in catabolism, anabolism and energetic metabolism and miRNAs expression in both the fast and slow muscle of juvenile pacu (Piaractus mesopotamicus) during food restriction and refeeding. Our analysis revealed that short periods of food restriction followed by refeeding predominantly affected fast muscle, with changes in muscle fiber diameter and miRNAs expression. There was an increase in the mRNA levels of catabolic pathways components (FBXO25, ATG12, BCL2) and energetic metabolism-related genes (PGC1α and SDHA), together with a decrease in PPARβ/δ mRNA levels. Interestingly, an increase in mRNA levels of anabolic genes (PI3K and mTORC1 complex: mTOR, mLST8 and RAPTOR) was also observed during food restriction. After refeeding, muscle morphology showed similar patterns of the control group; the majority of genes were slightly up- or down-regulated in fast and slow muscle, respectively; the levels of all miRNAs increased in fast muscle and some of them decreased in slow muscle. Our findings demonstrated that a short period of food restriction in juvenile pacu had a considerable impact on fast muscle, increasing the expression of anabolic (PI3K and mTORC1 complex: mTOR, mLST8 and RAPTOR) and energetic metabolism genes. The miRNAs (miR-1, miR-206, miR-199 and miR-23a) were more expressed during refeeding and while their target genes (IGF-1, mTOR, PGC1α and MAFbx), presented a decreased expression. The alterations in mTORC1 complex observed during fasting may have influenced the rates of protein synthesis by using amino acids from protein degradation as an alternative mechanism to preserve muscle phenotype and metabolic demand maintenance. PMID:28505179

  17. Food restriction increase the expression of mTORC1 complex genes in the skeletal muscle of juvenile pacu (Piaractus mesopotamicus.

    Directory of Open Access Journals (Sweden)

    Tassiana Gutierrez de Paula

    Full Text Available Skeletal muscle is capable of phenotypic adaptation to environmental factors, such as nutrient availability, by altering the balance between muscle catabolism and anabolism that in turn coordinates muscle growth. Small noncoding RNAs, known as microRNAs (miRNAs, repress the expression of target mRNAs, and many studies have demonstrated that miRNAs regulate the mRNAs of catabolic and anabolic genes. We evaluated muscle morphology, gene expression of components involved in catabolism, anabolism and energetic metabolism and miRNAs expression in both the fast and slow muscle of juvenile pacu (Piaractus mesopotamicus during food restriction and refeeding. Our analysis revealed that short periods of food restriction followed by refeeding predominantly affected fast muscle, with changes in muscle fiber diameter and miRNAs expression. There was an increase in the mRNA levels of catabolic pathways components (FBXO25, ATG12, BCL2 and energetic metabolism-related genes (PGC1α and SDHA, together with a decrease in PPARβ/δ mRNA levels. Interestingly, an increase in mRNA levels of anabolic genes (PI3K and mTORC1 complex: mTOR, mLST8 and RAPTOR was also observed during food restriction. After refeeding, muscle morphology showed similar patterns of the control group; the majority of genes were slightly up- or down-regulated in fast and slow muscle, respectively; the levels of all miRNAs increased in fast muscle and some of them decreased in slow muscle. Our findings demonstrated that a short period of food restriction in juvenile pacu had a considerable impact on fast muscle, increasing the expression of anabolic (PI3K and mTORC1 complex: mTOR, mLST8 and RAPTOR and energetic metabolism genes. The miRNAs (miR-1, miR-206, miR-199 and miR-23a were more expressed during refeeding and while their target genes (IGF-1, mTOR, PGC1α and MAFbx, presented a decreased expression. The alterations in mTORC1 complex observed during fasting may have influenced the rates of protein synthesis by using amino acids from protein degradation as an alternative mechanism to preserve muscle phenotype and metabolic demand maintenance.

  18. Human Cerberus prevents nodal-receptor binding, inhibits nodal signaling, and suppresses nodal-mediated phenotypes.

    Directory of Open Access Journals (Sweden)

    Senem Aykul

    Full Text Available The Transforming Growth Factor-ß (TGFß family ligand Nodal is an essential embryonic morphogen that is associated with progression of breast and other cancers. It has therefore been suggested that Nodal inhibitors could be used to treat breast cancers where Nodal plays a defined role. As secreted antagonists, such as Cerberus, tightly regulate Nodal signaling during embryonic development, we undertook to produce human Cerberus, characterize its biochemical activities, and determine its effect on human breast cancer cells. Using quantitative methods, we investigated the mechanism of Nodal signaling, we evaluated binding of human Cerberus to Nodal and other TGFß family ligands, and we characterized the mechanism of Nodal inhibition by Cerberus. Using cancer cell assays, we examined the ability of Cerberus to suppress aggressive breast cancer cell phenotypes. We found that human Cerberus binds Nodal with high affinity and specificity, blocks binding of Nodal to its signaling partners, and inhibits Nodal signaling. Moreover, we showed that Cerberus profoundly suppresses migration, invasion, and colony forming ability of Nodal expressing and Nodal supplemented breast cancer cells. Taken together, our studies provide mechanistic insights into Nodal signaling and Nodal inhibition with Cerberus and highlight the potential value of Cerberus as anti-Nodal therapeutic.

  19. MicroRNA-145 suppresses hepatocellular carcinoma by targeting IRS1 and its downstream Akt signaling

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yelin [Department of Anesthesiology, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou (China); Key Laboratory of Combined Multi-organ Transplantation, Ministry of Public Health, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou (China); Hu, Chen; Cheng, Jun [Department of Surgery, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou (China); Key Laboratory of Combined Multi-organ Transplantation, Ministry of Public Health, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou (China); Chen, Binquan [Department of Anesthesiology, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou (China); Ke, Qinghong; Lv, Zhen; Wu, Jian [Department of Surgery, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou (China); Key Laboratory of Combined Multi-organ Transplantation, Ministry of Public Health, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou (China); Zhou, Yanfeng, E-mail: zyfhdj@yahoo.com [Department of Anesthesiology, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou (China)

    2014-04-18

    Highlights: • MiR-145 expression is down-regulated in HCC tissues and inversely related with IRS1 levels. • MiR-145 directly targets IRS1 in HCC cells. • Restored expression of miR-145 suppressed HCC cell proliferation and growth. • MiR-145 induced IRS1 under-expression potentially reduced downstream AKT signaling. - Abstract: Accumulating evidences have proved that dysregulation of microRNAs (miRNAs) is involved in cancer initiation and progression. In this study, we showed that miRNA-145 level was significantly decreased in hepatocellular cancer (HCC) tissues and cell lines, and its low expression was inversely associated with the abundance of insulin receptor substrate 1 (IRS1), a key mediator in oncogenic insulin-like growth factor (IGF) signaling. We verified IRS1 as a direct target of miR-145 using Western blotting and luciferase reporter assay. Further, the restoration of miR-145 in HCC cell lines suppressed cancer cell growth, owing to down-regulated IRS1 expression and its downstream Akt/FOXO1 signaling. Our results demonstrated that miR-145 could inhibit HCC through targeting IRS1 and its downstream signaling, implicating the loss of miR-145 regulation may be a potential molecular mechanism causing aberrant oncogenic signaling in HCC.

  20. Curcumol suppresses RANKL-induced osteoclast formation by attenuating the JNK signaling pathway

    International Nuclear Information System (INIS)

    Yu, Mingxiang; Chen, Xianying; Lv, Chaoyang; Yi, Xilu; Zhang, Yao; Xue, Mengjuan; He, Shunmei; Zhu, Guoying; Wang, Hongfu

    2014-01-01

    Highlights: • Curcumol suppresses osteoclasts differentiation in vitro. • Curcumol impairs JNK/AP-1 signaling pathway. • Curcumol may be used for treating osteoclast related diseases. - Abstract: Osteoclasts, derived from hemopoietic progenitors of the monocyte/macrophage lineage, have a unique role in bone resorption, and are considered a potential therapeutic target in the treatment of such pathologic bone diseases as osteoporosis, rheumatoid arthritis, and periodontitis. In the present study, we demonstrate that curcumol, one of the major components of the essential oil of Rhizoma Curcumae, exhibits an inhibitory effect on receptor activator of nuclear factor kappaB ligand (RANKL)-induced osteoclast differentiation with both bone marrow-derived macrophages and RAW264.7 cells in a dose-dependent manner. In addition, RANKL-induced mRNA expression of osteoclast-specific genes, such as tartrate-resistant acid phosphatase, calcitonin receptor, and cathepsin K, is prominently reduced in the presence of curcumol. Furthermore, the molecular mechanism of action was investigated, and curcumol inhibited osteoclastogenesis by specifically impairing RANKL-induced c-Jun N-terminal kinase (JNK)/activator protein-1 (AP-1) signaling, which was further identified in rescue studies by means of anisomycin, a JNK signaling-specific activator. Taken together, these findings suggest that curcumol suppresses RANKL-induced osteoclast differentiation through the JNK/AP-1 signaling pathway, and may be useful as a therapeutic treatment for bone resorption-associated diseases

  1. Curcumol suppresses RANKL-induced osteoclast formation by attenuating the JNK signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Mingxiang, E-mail: yu.mingxiang@zs-hospital.sh.cn [Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai (China); Chen, Xianying [Department of Endocrinology and Metabolism, Hainan Provincial Nong Ken Hospital, Hainan (China); Lv, Chaoyang [Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai (China); Yi, Xilu [Department of Endocrinology and Metabolism, Shanghai Songjiang District Central Hospital, Shanghai (China); Zhang, Yao; Xue, Mengjuan; He, Shunmei [Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai (China); Zhu, Guoying [Institute of Radiation Medicine, Fudan University, Shanghai (China); Wang, Hongfu, E-mail: hfwang@shmu.edu.cn [Institute of Radiation Medicine, Fudan University, Shanghai (China)

    2014-05-02

    Highlights: • Curcumol suppresses osteoclasts differentiation in vitro. • Curcumol impairs JNK/AP-1 signaling pathway. • Curcumol may be used for treating osteoclast related diseases. - Abstract: Osteoclasts, derived from hemopoietic progenitors of the monocyte/macrophage lineage, have a unique role in bone resorption, and are considered a potential therapeutic target in the treatment of such pathologic bone diseases as osteoporosis, rheumatoid arthritis, and periodontitis. In the present study, we demonstrate that curcumol, one of the major components of the essential oil of Rhizoma Curcumae, exhibits an inhibitory effect on receptor activator of nuclear factor kappaB ligand (RANKL)-induced osteoclast differentiation with both bone marrow-derived macrophages and RAW264.7 cells in a dose-dependent manner. In addition, RANKL-induced mRNA expression of osteoclast-specific genes, such as tartrate-resistant acid phosphatase, calcitonin receptor, and cathepsin K, is prominently reduced in the presence of curcumol. Furthermore, the molecular mechanism of action was investigated, and curcumol inhibited osteoclastogenesis by specifically impairing RANKL-induced c-Jun N-terminal kinase (JNK)/activator protein-1 (AP-1) signaling, which was further identified in rescue studies by means of anisomycin, a JNK signaling-specific activator. Taken together, these findings suggest that curcumol suppresses RANKL-induced osteoclast differentiation through the JNK/AP-1 signaling pathway, and may be useful as a therapeutic treatment for bone resorption-associated diseases.

  2. SOCS3 in retinal neurons and glial cells suppresses VEGF signaling to prevent pathological neovascular growth.

    Science.gov (United States)

    Sun, Ye; Ju, Meihua; Lin, Zhiqiang; Fredrick, Thomas W; Evans, Lucy P; Tian, Katherine T; Saba, Nicholas J; Morss, Peyton C; Pu, William T; Chen, Jing; Stahl, Andreas; Joyal, Jean-Sébastien; Smith, Lois E H

    2015-09-22

    Neurons and glial cells in the retina contribute to neovascularization, or the formation of abnormal new blood vessels, in proliferative retinopathy, a condition that can lead to vision loss or blindness. We identified a mechanism by which suppressor of cytokine signaling 3 (SOCS3) in neurons and glial cells prevents neovascularization. We found that Socs3 expression was increased in the retinal ganglion cell and inner nuclear layers after oxygen-induced retinopathy. Mice with Socs3 deficiency in neuronal and glial cells had substantially reduced vaso-obliterated retinal areas and increased pathological retinal neovascularization in response to oxygen-induced retinopathy, suggesting that loss of neuronal/glial SOCS3 increased both retinal vascular regrowth and pathological neovascularization. Furthermore, retinal expression of Vegfa (which encodes vascular endothelial growth factor A) was higher in these mice than in Socs3 flox/flox controls, indicating that neuronal and glial SOCS3 suppressed Vegfa expression during pathological conditions. Lack of neuronal and glial SOCS3 resulted in greater phosphorylation and activation of STAT3, which led to increased expression of its gene target Vegfa, and increased endothelial cell proliferation. In summary, SOCS3 in neurons and glial cells inhibited the STAT3-mediated secretion of VEGF from these cells, which suppresses endothelial cell activation, resulting in decreased endothelial cell proliferation and angiogenesis. These results suggest that neuronal and glial cell SOCS3 limits pathological retinal angiogenesis by suppressing VEGF signaling. Copyright © 2015, American Association for the Advancement of Science.

  3. Diphlorethohydroxycarmalol from Ishige okamurae Suppresses Osteoclast Differentiation by Downregulating the NF-κB Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Hye Jung Ihn

    2017-12-01

    Full Text Available Marine algae possess a variety of beneficial effects on human health. In this study, we investigated whether diphlorethohydroxycarmalol (DPHC, isolated from Ishige okamurae, a brown alga, suppresses receptor activator of nuclear factor-κB ligand (RANKL-induced osteoclast differentiation. DPHC significantly suppressed RANKL-induced osteoclast differentiation and macrophage-colony stimulating factor (M-CSF expression in a dose-dependent manner. In addition, it significantly inhibited actin ring formation, the expression of osteoclast marker genes, such as tartrate-resistant acid phosphatase (TRAP, nuclear factor of activated T-cells cytoplasmic 1 (Nfatc1, cathepsin K (Ctsk, and dendritic cell-specific transmembrane protein (Dcstamp, and osteoclast-induced bone resorption. Analysis of the RANKL-mediated signaling pathway showed that the phosphorylation of both IκB and p65 was specifically inhibited by DPHC. These results suggest that DPHC substantially suppresses osteoclastogenesis by downregulating the RANK-NF-κB signaling pathway. Thus, it holds significant potential for the treatment of skeletal diseases associated with an enhanced osteoclast activity.

  4. Signaling Circuits and Regulation of Immune Suppression by Ovarian Tumor-Associated Macrophages

    Directory of Open Access Journals (Sweden)

    Martin J. Cannon

    2015-05-01

    Full Text Available The barriers presented by immune suppression in the ovarian tumor microenvironment present one of the biggest challenges to development of successful tumor vaccine strategies for prevention of disease recurrence and progression following primary surgery and chemotherapy. New insights gained over the last decade have revealed multiple mechanisms of immune regulation, with ovarian tumor-associated macrophages/DC likely to fulfill a central role in creating a highly immunosuppressive milieu that supports disease progression and blocks anti-tumor immunity. This review provides an appraisal of some of the key signaling pathways that may contribute to immune suppression in ovarian cancer, with a particular focus on the potential involvement of the c-KIT/PI3K/AKT, wnt/β-catenin, IL-6/STAT3 and AhR signaling pathways in regulation of indoleamine 2,3-dioxygenase expression in tumor-associated macrophages. Knowledge of intercellular and intracellular circuits that shape immune suppression may afford insights for development of adjuvant treatments that alleviate immunosuppression in the tumor microenvironment and enhance the clinical efficacy of ovarian tumor vaccines.

  5. Procyanidins Mitigate Osteoarthritis Pathogenesis by, at Least in Part, Suppressing Vascular Endothelial Growth Factor Signaling

    Directory of Open Access Journals (Sweden)

    Angela Wang

    2016-12-01

    Full Text Available Procyanidins are a family of plant metabolites that have been suggested to mitigate osteoarthritis pathogenesis in mice. However, the underlying mechanism is largely unknown. This study aimed to determine whether procyanidins mitigate traumatic injury-induced osteoarthritis (OA disease progression, and whether procyanidins exert a chondroprotective effect by, at least in part, suppressing vascular endothelial growth factor signaling. Procyanidins (extracts from pine bark, orally administered to mice subjected to surgery for destabilization of the medial meniscus, significantly slowed OA disease progression. Real-time polymerase chain reaction revealed that procyanidin treatment reduced expression of vascular endothelial growth factor and effectors in OA pathogenesis that are regulated by vascular endothelial growth factor. Procyanidin-suppressed vascular endothelial growth factor expression was correlated with reduced phosphorylation of vascular endothelial growth factor receptor 2 in human OA primary chondrocytes. Moreover, components of procyanidins, procyanidin B2 and procyanidin B3 exerted effects similar to those of total procyanidins in mitigating the OA-related gene expression profile in the primary culture of human OA chondrocytes in the presence of vascular endothelial growth factor. Together, these findings suggest procyanidins mitigate OA pathogenesis, which is mediated, at least in part, by suppressing vascular endothelial growth factor signaling.

  6. Radar signal pre-processing to suppress surface bounce and multipath

    Science.gov (United States)

    Paglieroni, David W; Mast, Jeffrey E; Beer, N. Reginald

    2013-12-31

    A method and system for detecting the presence of subsurface objects within a medium is provided. In some embodiments, the imaging and detection system operates in a multistatic mode to collect radar return signals generated by an array of transceiver antenna pairs that is positioned across the surface and that travels down the surface. The imaging and detection system pre-processes that return signal to suppress certain undesirable effects. The imaging and detection system then generates synthetic aperture radar images from real aperture radar images generated from the pre-processed return signal. The imaging and detection system then post-processes the synthetic aperture radar images to improve detection of subsurface objects. The imaging and detection system identifies peaks in the energy levels of the post-processed image frame, which indicates the presence of a subsurface object.

  7. Orthogonal matching pursuit algorithm and power line noise suppression of magnetotelluric signal

    Science.gov (United States)

    Li, Guang; Tang, Jingtian

    2017-11-01

    Power-line noise is mainly comes from power systems and has become one of the most common noises during the acquisition of magnetotelluric (MT) signal, its components including a fundamental frequency signal and a lot of odd harmonics. There are trap circuits designed in most of the acquisition instruments to separate these noise, however, the fundamental frequency of the power line noise will fluctuate with the changing of load current, but the center frequency of the trap circuits are fixed, hence the MT data are still seriously disturbed by the power line noise. To mitigate the disturbance of power line noise, a novel denoising method was proposed based on orthogonal matching pursuit (OMP) algorithm. Semisynthetic experiments and real data obtained from Lu-Zong ore-concentration district illustrate that the proposed method can effectively suppress the power line noise while remain the useful MT signal, the apparent resistivity and phase curves are greatly improved over previous.

  8. Sangivamycin induces apoptosis by suppressing Erk signaling in primary effusion lymphoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Wakao, Kazufumi [Department of Biotechnology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Kofu-shi 400-8511 (Japan); Watanabe, Tadashi [Department of Cell Biology, Kyoto Pharmaceutical University, Misasagi-Shichonocho 1, Yamashinaku, Kyoto 607-8412 (Japan); Takadama, Tadatoshi; Ui, Sadaharu [Department of Biotechnology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Kofu-shi 400-8511 (Japan); Shigemi, Zenpei; Kagawa, Hiroki [Department of Cell Biology, Kyoto Pharmaceutical University, Misasagi-Shichonocho 1, Yamashinaku, Kyoto 607-8412 (Japan); Higashi, Chizuka; Ohga, Rie; Taira, Takahiro [Department of Molecular Cell Biology, Faculty of Medicine, University of Yamanashi, Chuoh-shi 409-3898 (Japan); Fujimuro, Masahiro, E-mail: fuji2@mb.kyoto-phu.ac.jp [Department of Cell Biology, Kyoto Pharmaceutical University, Misasagi-Shichonocho 1, Yamashinaku, Kyoto 607-8412 (Japan)

    2014-02-07

    Highlights: • Sangivamycin induces the apoptosis of B cell lymphoma PEL cells. • Sangivamycin suppresses Erk signaling by inhibiting Erk phosphorylation in PEL cells. • The activation of Erk signaling is essential for PEL cell survival. • Sangivamycin induces the apoptosis of PEL cells without production of progeny virus. • Sangivamycin may serve as a novel drug for the treatment of PEL. - Abstract: Sangivamycin, a structural analog of adenosine and antibiotic exhibiting antitumor and antivirus activities, inhibits protein kinase C and the synthesis of both DNA and RNA. Primary effusion lymphoma (PEL) is an aggressive neoplasm caused by Kaposi’s sarcoma-associated herpesvirus (KSHV) in immunosuppressed patients and HIV-infected homosexual males. PEL cells are derived from post-germinal center B cells, and are infected with KSHV. Herein, we asked if sangivamycin might be useful to treat PEL. We found that sangivamycin killed PEL cells, and we explored the underlying mechanism. Sangivamycin treatment drastically decreased the viability of PEL cell lines compared to KSHV-uninfected B lymphoma cell lines. Sangivamycin induced the apoptosis of PEL cells by activating caspase-7 and -9. Further, sangivamycin suppressed the phosphorylation of Erk1/2 and Akt, thus inhibiting activation of the proteins. Inhibitors of Akt and MEK suppressed the proliferation of PEL cells compared to KSHV-uninfected cells. It is known that activation of Erk and Akt signaling inhibits apoptosis and promotes proliferation in PEL cells. Our data therefore suggest that sangivamycin induces apoptosis by inhibiting Erk and Akt signaling in such cells. We next investigated whether sangivamycin, in combination with an HSP90 inhibitor geldanamycin (GA) or valproate (valproic acid), potentiated the cytotoxic effects of the latter drugs on PEL cells. Compared to treatment with GA or valproate alone, the addition of sangivamycin enhanced cytotoxic activity. Our data thus indicate that

  9. Sangivamycin induces apoptosis by suppressing Erk signaling in primary effusion lymphoma cells

    International Nuclear Information System (INIS)

    Wakao, Kazufumi; Watanabe, Tadashi; Takadama, Tadatoshi; Ui, Sadaharu; Shigemi, Zenpei; Kagawa, Hiroki; Higashi, Chizuka; Ohga, Rie; Taira, Takahiro; Fujimuro, Masahiro

    2014-01-01

    Highlights: • Sangivamycin induces the apoptosis of B cell lymphoma PEL cells. • Sangivamycin suppresses Erk signaling by inhibiting Erk phosphorylation in PEL cells. • The activation of Erk signaling is essential for PEL cell survival. • Sangivamycin induces the apoptosis of PEL cells without production of progeny virus. • Sangivamycin may serve as a novel drug for the treatment of PEL. - Abstract: Sangivamycin, a structural analog of adenosine and antibiotic exhibiting antitumor and antivirus activities, inhibits protein kinase C and the synthesis of both DNA and RNA. Primary effusion lymphoma (PEL) is an aggressive neoplasm caused by Kaposi’s sarcoma-associated herpesvirus (KSHV) in immunosuppressed patients and HIV-infected homosexual males. PEL cells are derived from post-germinal center B cells, and are infected with KSHV. Herein, we asked if sangivamycin might be useful to treat PEL. We found that sangivamycin killed PEL cells, and we explored the underlying mechanism. Sangivamycin treatment drastically decreased the viability of PEL cell lines compared to KSHV-uninfected B lymphoma cell lines. Sangivamycin induced the apoptosis of PEL cells by activating caspase-7 and -9. Further, sangivamycin suppressed the phosphorylation of Erk1/2 and Akt, thus inhibiting activation of the proteins. Inhibitors of Akt and MEK suppressed the proliferation of PEL cells compared to KSHV-uninfected cells. It is known that activation of Erk and Akt signaling inhibits apoptosis and promotes proliferation in PEL cells. Our data therefore suggest that sangivamycin induces apoptosis by inhibiting Erk and Akt signaling in such cells. We next investigated whether sangivamycin, in combination with an HSP90 inhibitor geldanamycin (GA) or valproate (valproic acid), potentiated the cytotoxic effects of the latter drugs on PEL cells. Compared to treatment with GA or valproate alone, the addition of sangivamycin enhanced cytotoxic activity. Our data thus indicate that

  10. Targeting of the Hedgehog signal transduction pathway suppresses survival of malignant pleural mesothelioma cells in vitro.

    Science.gov (United States)

    You, Min; Varona-Santos, Javier; Singh, Samer; Robbins, David J; Savaraj, Niramol; Nguyen, Dao M

    2014-01-01

    The present study sought to determine whether the Hedgehog (Hh) pathway is active and regulates the cell growth of cultured malignant pleural mesothelioma (MPM) cells and to evaluate the efficacy of pathway blockade using smoothened (SMO) antagonists (SMO inhibitor GDC-0449 or the antifungal drug itraconazole [ITRA]) or Gli inhibitors (GANT61 or the antileukemia drug arsenic trioxide [ATO]) in suppressing MPM viability. Selective knockdown of SMO to inhibit Hh signaling was achieved by small interfering RNA in 3 representative MPM cells. The growth inhibitory effect of GDC-0449, ITRA, GANT61, and ATO was evaluated in 8 MPM lines, with cell viability quantified using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell death was determined by annexinV/propidium iodide staining and flow cytometry. SMO small interfering RNA mediated a two- to more than fivefold reduction of SMO and Gli1 gene expression as determined by real-time quantitative reverse-transcriptase polymerase chain reaction, indicating significant Hh pathway blockade. This was associated with significantly reduced cell viability (34% ± 7% to 61% ± 14% of nontarget small interfering RNA controls; P = .0024 to P = .043). Treating MPM cells with Hh inhibitors resulted in a 1.5- to 4-fold reduction of Gli1 expression. These 4 Hh antagonists strongly suppressed MPM cell viability. More importantly, ITRA, ATO, GANT61 induced significant apoptosis in the representative MPM cells. Hh signaling is active in MPM and regulates cell viability. ATO and ITRA were as effective as the prototypic SMO inhibitor GDC-0449 and the Gli inhibitor GANT61 in suppressing Hh signaling in MPM cells. Pharmaceutical agents Food and Drug Administration-approved for other indications but recently found to have anti-Hh activity, such as ATO or ITRA, could be repurposed to treat MPM. Copyright © 2014 The American Association for Thoracic Surgery. All rights reserved.

  11. Efficacy of Mesenchymal Stem Cells in Suppression of Hepatocarcinorigenesis in Rats: Possible Role of Wnt Signaling

    Directory of Open Access Journals (Sweden)

    Sabry Dina

    2011-05-01

    Full Text Available Abstract Background The present study was conducted to evaluate the tumor suppressive effects of bone marrow derived mesenchymal stem cells (MSCs in an experimental hepatocellular carcinoma (HCC model in rats and to investigate the possible role of Wnt signaling in hepato-carcinogenesis. Methods Ninety rats were included in the study and were divided equally into: Control group, rats which received MSCs only, rats which received MSCs vehicle only, HCC group induced by diethylnitroseamine (DENA and CCl4, rats which received MSCs after HCC induction, rats which received MSCs before HCC induction. Histopathological examination and gene expression of Wnt signaling target genes by real time, reverse transcription-polymerase chain reaction (RT-PCR in rat liver tissue, in addition to serum levels of ALT, AST and alpha fetoprotein were performed in all groups. Results Histopathological examination of liver tissue from animals which received DENA-CCl4 only, revealed the presence of anaplastic carcinoma cells and macro-regenerative nodules type II with foci of large and small cell dysplasia. Administration of MSCs into rats after induction of experimental HCC improved the histopathological picture which showed minimal liver cell damage, reversible changes, areas of cell drop out filled with stem cells. Gene expression in rat liver tissue demonstrated that MSCs downregulated β-catenin, proliferating cell nuclear antigen (PCNA, cyclin D and survivin genes expression in liver tissues after HCC induction. Amelioration of the liver status after administration of MSCs has been inferred by the significant decrease of ALT, AST and Alpha fetoprotein serum levels. Administration of MSCs before HCC induction did not show any tumor suppressive or protective effect. Conclusions Administration of MSCs in chemically induced HCC has tumor suppressive effects as evidenced by down regulation of Wnt signaling target genes concerned with antiapoptosis, mitogenesis, cell

  12. Efficacy of Mesenchymal Stem Cells in Suppression of Hepatocarcinorigenesis in Rats: Possible Role of Wnt Signaling

    LENUS (Irish Health Repository)

    Abdel Aziz, Mohamed T

    2011-05-05

    Abstract Background The present study was conducted to evaluate the tumor suppressive effects of bone marrow derived mesenchymal stem cells (MSCs) in an experimental hepatocellular carcinoma (HCC) model in rats and to investigate the possible role of Wnt signaling in hepato-carcinogenesis. Methods Ninety rats were included in the study and were divided equally into: Control group, rats which received MSCs only, rats which received MSCs vehicle only, HCC group induced by diethylnitroseamine (DENA) and CCl 4 , rats which received MSCs after HCC induction, rats which received MSCs before HCC induction. Histopathological examination and gene expression of Wnt signaling target genes by real time, reverse transcription-polymerase chain reaction (RT-PCR) in rat liver tissue, in addition to serum levels of ALT, AST and alpha fetoprotein were performed in all groups. Results Histopathological examination of liver tissue from animals which received DENA-CCl4 only, revealed the presence of anaplastic carcinoma cells and macro-regenerative nodules type II with foci of large and small cell dysplasia. Administration of MSCs into rats after induction of experimental HCC improved the histopathological picture which showed minimal liver cell damage, reversible changes, areas of cell drop out filled with stem cells. Gene expression in rat liver tissue demonstrated that MSCs downregulated β-catenin, proliferating cell nuclear antigen (PCNA), cyclin D and survivin genes expression in liver tissues after HCC induction. Amelioration of the liver status after administration of MSCs has been inferred by the significant decrease of ALT, AST and Alpha fetoprotein serum levels. Administration of MSCs before HCC induction did not show any tumor suppressive or protective effect. Conclusions Administration of MSCs in chemically induced HCC has tumor suppressive effects as evidenced by down regulation of Wnt signaling target genes concerned with antiapoptosis, mitogenesis, cell proliferation

  13. A paradoxical signal intensity increase in fatty livers using opposed-phase gradient echo imaging with fat-suppression pulses

    Energy Technology Data Exchange (ETDEWEB)

    Mulkern, Robert V.; Voss, Stephan [Harvard Medical School, Department of Radiology, Children' s Hospital Boston, Boston, MA (United States); Loeb Salsberg, Sandra; Krauel, Marta Ramon; Ludwig, David S. [Harvard Medical School, Department of Medicine, Children' s Hospital Boston, Boston, MA (United States)

    2008-10-15

    With the increase in obese and overweight children, nonalcoholic fatty liver disease has become more prevalent in the pediatric population. Appreciating subtleties of magnetic resonance (MR) signal intensity behavior from fatty livers under different imaging conditions thus becomes important to pediatric radiologists. We report an initially confusing signal behavior - increased signal from fatty livers when fat-suppression pulses are applied in an opposed-phase gradient echo imaging sequence - and seek to explain the physical mechanisms for this paradoxical signal intensity behavior. Abdominal MR imaging at 3 T with a 3-D volumetric interpolated breath-hold (VIBE) sequence in the opposed-phase condition (TR/TE 3.3/1.3 ms) was performed in five obese boys (14{+-}2 years of age, body mass index >95th percentile for age and sex) with spectroscopically confirmed fatty livers. Two VIBE acquisitions were performed, one with and one without the use of chemical shift selective (CHESS) pulse fat suppression. The ratios of fat-suppressed over non-fat-suppressed signal intensities were assessed in regions-of-interest (ROIs) in five tissues: subcutaneous fat, liver, vertebral marrow, muscle and spleen. The boys had spectroscopically estimated hepatic fat levels between 17% and 48%. CHESS pulse fat suppression decreased subcutaneous fat signals dramatically, by more than 85% within regions of optimal fat suppression. Fatty liver signals, in contrast, were elevated by an average of 87% with CHESS pulse fat suppression. Vertebral marrow signal was also significantly elevated with CHESS pulse fat suppression, while spleen and muscle signals demonstrated only small signal increases on the order of 10%. We demonstrated that CHESS pulse fat suppression actually increases the signal intensity from fatty livers in opposed-phase gradient echo imaging conditions. The increase can be attributed to suppression of one partner of the opposed-phase pair that normally contributes to the

  14. A paradoxical signal intensity increase in fatty livers using opposed-phase gradient echo imaging with fat-suppression pulses

    International Nuclear Information System (INIS)

    Mulkern, Robert V.; Voss, Stephan; Loeb Salsberg, Sandra; Krauel, Marta Ramon; Ludwig, David S.

    2008-01-01

    With the increase in obese and overweight children, nonalcoholic fatty liver disease has become more prevalent in the pediatric population. Appreciating subtleties of magnetic resonance (MR) signal intensity behavior from fatty livers under different imaging conditions thus becomes important to pediatric radiologists. We report an initially confusing signal behavior - increased signal from fatty livers when fat-suppression pulses are applied in an opposed-phase gradient echo imaging sequence - and seek to explain the physical mechanisms for this paradoxical signal intensity behavior. Abdominal MR imaging at 3 T with a 3-D volumetric interpolated breath-hold (VIBE) sequence in the opposed-phase condition (TR/TE 3.3/1.3 ms) was performed in five obese boys (14±2 years of age, body mass index >95th percentile for age and sex) with spectroscopically confirmed fatty livers. Two VIBE acquisitions were performed, one with and one without the use of chemical shift selective (CHESS) pulse fat suppression. The ratios of fat-suppressed over non-fat-suppressed signal intensities were assessed in regions-of-interest (ROIs) in five tissues: subcutaneous fat, liver, vertebral marrow, muscle and spleen. The boys had spectroscopically estimated hepatic fat levels between 17% and 48%. CHESS pulse fat suppression decreased subcutaneous fat signals dramatically, by more than 85% within regions of optimal fat suppression. Fatty liver signals, in contrast, were elevated by an average of 87% with CHESS pulse fat suppression. Vertebral marrow signal was also significantly elevated with CHESS pulse fat suppression, while spleen and muscle signals demonstrated only small signal increases on the order of 10%. We demonstrated that CHESS pulse fat suppression actually increases the signal intensity from fatty livers in opposed-phase gradient echo imaging conditions. The increase can be attributed to suppression of one partner of the opposed-phase pair that normally contributes to the

  15. Suppression of Quasiparticle Scattering Signals in Bilayer Graphene Due to Layer Polarization and Destructive Interference

    Science.gov (United States)

    Jolie, Wouter; Lux, Jonathan; Pörtner, Mathias; Dombrowski, Daniela; Herbig, Charlotte; Knispel, Timo; Simon, Sabina; Michely, Thomas; Rosch, Achim; Busse, Carsten

    2018-03-01

    We study chemically gated bilayer graphene using scanning tunneling microscopy and spectroscopy complemented by tight-binding calculations. Gating is achieved by intercalating Cs between bilayer graphene and Ir(111), thereby shifting the conduction band minima below the chemical potential. Scattering between electronic states (both intraband and interband) is detected via quasiparticle interference. However, not all expected processes are visible in our experiment. We uncover two general effects causing this suppression: first, intercalation leads to an asymmetrical distribution of the states within the two layers, which significantly reduces the scanning tunneling spectroscopy signal of standing waves mainly present in the lower layer; second, forward scattering processes, connecting points on the constant energy contours with parallel velocities, do not produce pronounced standing waves due to destructive interference. We present a theory to describe the interference signal for a general n -band material.

  16. Piperlongumine inhibits atherosclerotic plaque formation and vascular smooth muscle cell proliferation by suppressing PDGF receptor signaling

    International Nuclear Information System (INIS)

    Son, Dong Ju; Kim, Soo Yeon; Han, Seong Su; Kim, Chan Woo; Kumar, Sandeep; Park, Byeoung Soo; Lee, Sung Eun; Yun, Yeo Pyo; Jo, Hanjoong; Park, Young Hyun

    2012-01-01

    Highlights: ► Anti-atherogenic effect of PL was examined using partial carotid ligation model in ApoE KO mice. ► PL prevented atherosclerotic plaque development, VSMCs proliferation, and NF-κB activation. ► Piperlongumine reduced vascular smooth muscle cell activation through PDGF-Rβ and NF-κB-signaling. ► PL may serve as a new therapeutic molecule for atherosclerosis treatment. -- Abstract: Piperlongumine (piplartine, PL) is an alkaloid found in the long pepper (Piper longum L.) and has well-documented anti-platelet aggregation, anti-inflammatory, and anti-cancer properties; however, the role of PL in prevention of atherosclerosis is unknown. We evaluated the anti-atherosclerotic potential of PL in an in vivo murine model of accelerated atherosclerosis and defined its mechanism of action in aortic vascular smooth muscle cells (VSMCs) in vitro. Local treatment with PL significantly reduced atherosclerotic plaque formation as well as proliferation and nuclear factor-kappa B (NF-κB) activation in an in vivo setting. PL treatment in VSMCs in vitro showed inhibition of migration and platelet-derived growth factor BB (PDGF-BB)-induced proliferation to the in vivo findings. We further identified that PL inhibited PDGF-BB-induced PDGF receptor beta activation and suppressed downstream signaling molecules such as phospholipase Cγ1, extracellular signal-regulated kinases 1 and 2 and Akt. Lastly, PL significantly attenuated activation of NF-κB—a downstream transcriptional regulator in PDGF receptor signaling, in response to PDGF-BB stimulation. In conclusion, our findings demonstrate a novel, therapeutic mechanism by which PL suppresses atherosclerosis plaque formation in vivo.

  17. Dectin-1 Regulates Hepatic Fibrosis and Hepatocarcinogenesis by Suppressing TLR4 Signaling Pathways

    Directory of Open Access Journals (Sweden)

    Lena Seifert

    2015-12-01

    Full Text Available Dectin-1 is a C-type lectin receptor critical in anti-fungal immunity, but Dectin-1 has not been linked to regulation of sterile inflammation or oncogenesis. We found that Dectin-1 expression is upregulated in hepatic fibrosis and liver cancer. However, Dectin-1 deletion exacerbates liver fibro-inflammatory disease and accelerates hepatocarcinogenesis. Mechanistically, we found that Dectin-1 protects against chronic liver disease by suppressing TLR4 signaling in hepatic inflammatory and stellate cells. Accordingly, Dectin-1–/– mice exhibited augmented cytokine production and reduced survival in lipopolysaccharide (LPS-mediated sepsis, whereas Dectin-1 activation was protective. We showed that Dectin-1 inhibits TLR4 signaling by mitigating TLR4 and CD14 expression, which are regulated by Dectin-1-dependent macrophage colony stimulating factor (M-CSF expression. Our study suggests that Dectin-1 is an attractive target for experimental therapeutics in hepatic fibrosis and neoplastic transformation. More broadly, our work deciphers critical cross-talk between pattern recognition receptors and implicates a role for Dectin-1 in suppression of sterile inflammation, inflammation-induced oncogenesis, and LPS-mediated sepsis.

  18. Andrographolide suppresses TRIF-dependent signaling of toll-like receptors by targeting TBK1.

    Science.gov (United States)

    Kim, Ah-Yeon; Shim, Hyun-Jin; Shin, Hyeon-Myeong; Lee, Yoo Jung; Nam, Hyeonjeong; Kim, Su Yeon; Youn, Hyung-Sun

    2018-04-01

    Toll-like receptors (TLRs) play a crucial role in danger recognition and induction of innate immune response against bacterial and viral infections. The TLR adaptor molecule, toll-interleukin-1 receptor domain-containing adapter inducing interferon-β (TRIF), facilitates TLR3 and TLR4 signaling, leading to the activation of the transcription factor, NF-κB and interferon regulatory factor 3 (IRF3). Andrographolide, the active component of Andrographis paniculata, exerts anti-inflammatory effects; however, the principal molecular mechanisms remain unclear. The objective of this study was to investigate the role of andrographolide in TLR signaling pathways. Andrographolide suppressed NF-κB activation as well as COX-2 expression induced by TLR3 or TLR4 agonists. Andrographolide also suppressed the activation of IRF3 and the expression of interferon inducible protein-10 (IP-10) induced by TLR3 or TLR4 agonists. Andrographolide attenuated ligand-independent activation of IRF3 following overexpression of TRIF, TBK1, or IRF3. Furthermore, andrographolide inhibited TBK1 kinase activity in vitro. These results indicate that andrographolide modulates the TRIF-dependent pathway of TLRs by targeting TBK1 and represents a potential new anti-inflammatory candidate. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. Ceftriaxone Protects Astrocytes from MPP(+) via Suppression of NF-κB/JNK/c-Jun Signaling.

    Science.gov (United States)

    Zhang, Yunlong; Zhang, Xiuping; Qu, Shaogang

    2015-08-01

    Ceftriaxone has been shown to attenuate the dopaminergic neuron death and alleviate behavioral disorders in Parkinson's disease models via upregulation of glutamate transporter-1 (GLT-1) and decreases in extracellular glutamate. However, details of how this neuroprotection occurs are uncertain. We hypothesized that cytoprotection by ceftriaxone in astrocytes exposed to 1-methyl-4-phenylpyridinium (MPP(+)) involves suppression of the NF-κB/JNK/c-Jun signaling pathway. Here, we observed a protective effect of ceftriaxone in primary astrocytes exposed to MPP(+). Ceftriaxone enhanced glutamate uptake and promoted primary astrocyte viability after MPP(+) exposure. Ceftriaxone enhances glutamate uptake via upregulation of GLT-1 in the plasma membrane, and alleviates MPP(+)-induced neurotoxicity via suppression of NF-κB/JNK/c-Jun signaling. Collectively, our data offer evidence that increased expression and function of GLT-1 are involved in the protective mechanism of ceftriaxone in astrocytes exposed to MPP(+) in vitro, and we offer insight into the potential therapeutic role of ceftriaxone in treatment of Parkinson's disease.

  20. Histamine Derived from Probiotic Lactobacillus reuteri Suppresses TNF via Modulation of PKA and ERK Signaling

    Science.gov (United States)

    Thomas, Carissa M.; Hong, Teresa; van Pijkeren, Jan Peter; Hemarajata, Peera; Trinh, Dan V.; Hu, Weidong; Britton, Robert A.; Kalkum, Markus; Versalovic, James

    2012-01-01

    Beneficial microbes and probiotic species, such as Lactobacillus reuteri, produce biologically active compounds that can modulate host mucosal immunity. Previously, immunomodulatory factors secreted by L. reuteri ATCC PTA 6475 were unknown. A combined metabolomics and bacterial genetics strategy was utilized to identify small compound(s) produced by L. reuteri that were TNF-inhibitory. Hydrophilic interaction liquid chromatography-high performance liquid chromatography (HILIC-HPLC) separation isolated TNF-inhibitory compounds, and HILIC-HPLC fraction composition was determined by NMR and mass spectrometry analyses. Histamine was identified and quantified in TNF-inhibitory HILIC-HPLC fractions. Histamine is produced from L-histidine via histidine decarboxylase by some fermentative bacteria including lactobacilli. Targeted mutagenesis of each gene present in the histidine decarboxylase gene cluster in L. reuteri 6475 demonstrated the involvement of histidine decarboxylase pyruvoyl type A (hdcA), histidine/histamine antiporter (hdcP), and hdcB in production of the TNF-inhibitory factor. The mechanism of TNF inhibition by L. reuteri-derived histamine was investigated using Toll-like receptor 2 (TLR2)-activated human monocytoid cells. Bacterial histamine suppressed TNF production via activation of the H2 receptor. Histamine from L. reuteri 6475 stimulated increased levels of cAMP, which inhibited downstream MEK/ERK MAPK signaling via protein kinase A (PKA) and resulted in suppression of TNF production by transcriptional regulation. In summary, a component of the gut microbiome, L. reuteri, is able to convert a dietary component, L-histidine, into an immunoregulatory signal, histamine, which suppresses pro-inflammatory TNF production. The identification of bacterial bioactive metabolites and their corresponding mechanisms of action with respect to immunomodulation may lead to improved anti-inflammatory strategies for chronic immune-mediated diseases. PMID:22384111

  1. Histamine derived from probiotic Lactobacillus reuteri suppresses TNF via modulation of PKA and ERK signaling.

    Directory of Open Access Journals (Sweden)

    Carissa M Thomas

    Full Text Available Beneficial microbes and probiotic species, such as Lactobacillus reuteri, produce biologically active compounds that can modulate host mucosal immunity. Previously, immunomodulatory factors secreted by L. reuteri ATCC PTA 6475 were unknown. A combined metabolomics and bacterial genetics strategy was utilized to identify small compound(s produced by L. reuteri that were TNF-inhibitory. Hydrophilic interaction liquid chromatography-high performance liquid chromatography (HILIC-HPLC separation isolated TNF-inhibitory compounds, and HILIC-HPLC fraction composition was determined by NMR and mass spectrometry analyses. Histamine was identified and quantified in TNF-inhibitory HILIC-HPLC fractions. Histamine is produced from L-histidine via histidine decarboxylase by some fermentative bacteria including lactobacilli. Targeted mutagenesis of each gene present in the histidine decarboxylase gene cluster in L. reuteri 6475 demonstrated the involvement of histidine decarboxylase pyruvoyl type A (hdcA, histidine/histamine antiporter (hdcP, and hdcB in production of the TNF-inhibitory factor. The mechanism of TNF inhibition by L. reuteri-derived histamine was investigated using Toll-like receptor 2 (TLR2-activated human monocytoid cells. Bacterial histamine suppressed TNF production via activation of the H(2 receptor. Histamine from L. reuteri 6475 stimulated increased levels of cAMP, which inhibited downstream MEK/ERK MAPK signaling via protein kinase A (PKA and resulted in suppression of TNF production by transcriptional regulation. In summary, a component of the gut microbiome, L. reuteri, is able to convert a dietary component, L-histidine, into an immunoregulatory signal, histamine, which suppresses pro-inflammatory TNF production. The identification of bacterial bioactive metabolites and their corresponding mechanisms of action with respect to immunomodulation may lead to improved anti-inflammatory strategies for chronic immune-mediated diseases.

  2. Receptor for advanced glycation end products inhibits proliferation in osteoblast through suppression of Wnt, PI3K and ERK signaling

    International Nuclear Information System (INIS)

    Li, Guofeng; Xu, Jingren; Li, Zengchun

    2012-01-01

    Highlights: ► RAGE overexpression suppresses cell proliferation in MC3T3-E1 cells. ► RAGE overexpression decreases Wnt/β-catenin signaling. ► RAGE overexpression decreases ERK and PI3K signaling. ► Inhibition of Wnt signaling abolishes PI3K signaling restored by RAGE blockade. ► Inhibition of Wnt signaling abolishes ERK signaling restored by RAGE blockade. -- Abstract: Expression of receptor for advanced glycation end products (RAGE) plays a crucial role in bone metabolism. However, the role of RAGE in the control of osteoblast proliferation is not yet evaluated. In the present study, we demonstrate that RAGE overexpression inhibits osteoblast proliferation in vitro. The negative regulation of RAGE on cell proliferation results from suppression of Wnt, PI3K and ERK signaling, and is restored by RAGE neutralizing antibody. Prevention of Wnt signaling using Sfrp1 or DKK1 rescues RAGE-decreased PI3K and ERK signaling and cell proliferation, indicating that the altered cell growth in RAGE overexpressing cells is in part secondary to alterations in Wnt signaling. Consistently, RAGE overexpression inhibits the expression of Wnt targets cyclin D1 and c-myc, which is partially reversed by RAGE blockade. Overall, these results suggest that RAGE inhibits osteoblast proliferation via suppression of Wnt, PI3K and ERK signaling, which provides novel mechanisms by which RAGE regulates osteoblast growth.

  3. Receptor for advanced glycation end products inhibits proliferation in osteoblast through suppression of Wnt, PI3K and ERK signaling

    Energy Technology Data Exchange (ETDEWEB)

    Li, Guofeng [Department of Emergency Surgery, East Hospital, Tongji University School of Medicine, Shanghai 200120 (China); Xu, Jingren [Department of Traditional Chinese Orthopaedics, East Hospital, Tongji University School of Medicine, Shanghai 200120 (China); Li, Zengchun, E-mail: lizc.2007@yahoo.com.cn [Department of Emergency Surgery, East Hospital, Tongji University School of Medicine, Shanghai 200120 (China)

    2012-07-13

    Highlights: Black-Right-Pointing-Pointer RAGE overexpression suppresses cell proliferation in MC3T3-E1 cells. Black-Right-Pointing-Pointer RAGE overexpression decreases Wnt/{beta}-catenin signaling. Black-Right-Pointing-Pointer RAGE overexpression decreases ERK and PI3K signaling. Black-Right-Pointing-Pointer Inhibition of Wnt signaling abolishes PI3K signaling restored by RAGE blockade. Black-Right-Pointing-Pointer Inhibition of Wnt signaling abolishes ERK signaling restored by RAGE blockade. -- Abstract: Expression of receptor for advanced glycation end products (RAGE) plays a crucial role in bone metabolism. However, the role of RAGE in the control of osteoblast proliferation is not yet evaluated. In the present study, we demonstrate that RAGE overexpression inhibits osteoblast proliferation in vitro. The negative regulation of RAGE on cell proliferation results from suppression of Wnt, PI3K and ERK signaling, and is restored by RAGE neutralizing antibody. Prevention of Wnt signaling using Sfrp1 or DKK1 rescues RAGE-decreased PI3K and ERK signaling and cell proliferation, indicating that the altered cell growth in RAGE overexpressing cells is in part secondary to alterations in Wnt signaling. Consistently, RAGE overexpression inhibits the expression of Wnt targets cyclin D1 and c-myc, which is partially reversed by RAGE blockade. Overall, these results suggest that RAGE inhibits osteoblast proliferation via suppression of Wnt, PI3K and ERK signaling, which provides novel mechanisms by which RAGE regulates osteoblast growth.

  4. Efficient retina formation requires suppression of both Activin and BMP signaling pathways in pluripotent cells

    Directory of Open Access Journals (Sweden)

    Kimberly A. Wong

    2015-03-01

    Full Text Available Retina formation requires the correct spatiotemporal patterning of key regulatory factors. While it is known that repression of several signaling pathways lead to specification of retinal fates, addition of only Noggin, a known BMP antagonist, can convert pluripotent Xenopus laevis animal cap cells to functional retinal cells. The aim of this study is to determine the intracellular molecular events that occur during this conversion. Surprisingly, blocking BMP signaling alone failed to mimic Noggin treatment. Overexpressing Noggin in pluripotent cells resulted in a concentration-dependent suppression of both Smad1 and Smad2 phosphorylation, which act downstream of BMP and Activin signaling, respectively. This caused a decrease in downstream targets: endothelial marker, xk81, and mesodermal marker, xbra. We treated pluripotent cells with dominant-negative receptors or the chemical inhibitors, dorsomorphin and SB431542, which each target either the BMP or Activin signaling pathway. We determined the effect of these treatments on retina formation using the Animal Cap Transplant (ACT assay; in which treated pluripotent cells were transplanted into the eye field of host embryos. We found that inhibition of Activin signaling, in the presence of BMP signaling inhibition, promotes efficient retinal specification in Xenopus tissue, mimicking the affect of adding Noggin alone. In whole embryos, we found that the eye field marker, rax, expanded when adding both dominant-negative Smad1 and Smad2, as did treating the cells with both dorsomorphin and SB431542. Future studies could translate these findings to a mammalian culture assay, in order to more efficiently produce retinal cells in culture.

  5. Orexin-A Suppresses Signal Transmission to Dopaminergic Amacrine Cells From Outer and Inner Retinal Photoreceptors.

    Science.gov (United States)

    Qiao, Sheng-Nan; Zhou, Wei; Liu, Lei-Lei; Zhang, Dao-Qi; Zhong, Yong-Mei

    2017-09-01

    The neuropeptides orexin-A and orexin-B are widely expressed in the vertebrate retina; however, their role in visual function is unclear. This study investigates whether and how orexins modulate signal transmission to dopaminergic amacrine cells (DACs) from both outer retinal photoreceptors (rods and cones) and inner retinal photoreceptors (melanopsin-expressing intrinsically photosensitive retinal ganglion cells [ipRGCs]). A whole-cell voltage-clamp technique was used to record light-induced responses from genetically labeled DACs in flat-mount mouse retinas. Rod and cone signaling to DACs was confirmed pharmacologically (in wild-type retinas), whereas retrograde melanopsin signaling to DACs was isolated either pharmacologically (in wild-type retinas) or by genetic deletion of rod and cone function (in transgenic mice). Orexin-A attenuated rod/cone-mediated light responses in the majority of DACs and inhibited all DACs that exhibited melanopsin-based light responses, suggesting that exogenous orexin suppresses signal transmission from rods, cones, and ipRGCs to DACs. In addition, orexin receptor 1 antagonist SB334867 and orexin receptor 2 antagonist TCS OX229 enhanced melanopsin-based DAC responses, indicating that endogenous orexins inhibit signal transmission from ipRGCs to DACs. We further found that orexin-A inhibits melanopsin-based DAC responses via orexin receptors on DACs, whereas orexin-A may modulate signal transmission from rods and cones to DACs through activation of orexin receptors on DACs and their upstream neurons. Our results suggest that orexins could influence visual function via the dopaminergic system in the mammalian retina.

  6. Constitutively Active Parathyroid Hormone Receptor Signaling in Cells in Osteoblastic Lineage Suppresses Mechanical Unloading-induced Bone Resorption*

    Science.gov (United States)

    Ono, Noriaki; Nakashima, Kazuhisa; Schipani, Ernestina; Hayata, Tadayoshi; Ezura, Yoichi; Soma, Kunimichi; Kronenberg, Henry M.; Noda, Masaki

    2013-01-01

    Multiple signaling pathways participate in the regulation of bone remodeling, and pathological negative balance in the regulation results in osteoporosis. However, interactions of signaling pathways that act comprehensively in concert to maintain bone mass are not fully understood. We investigated roles of parathyroid hormone receptor (PTH/PTHrP receptor) signaling in osteoblasts in unloading-induced bone loss using transgenic mice. Hind limb unloading by tail suspension reduced bone mass in wild-type mice. In contrast, signaling by constitutively active PTH/PTHrP receptor (caPPR), whose expression was regulated by the osteoblast-specific Col1a1 promoter (Col1a1-caPPR), suppressed unloading-induced reduction in bone mass in these transgenic mice. In Col1a1-caPPR transgenic (Tg) mice, hind limb unloading suppressed bone formation parameters in vivo and mineralized nodule formation in vitro similarly to those observed in wild-type mice. In addition, serum osteocalcin levels and mRNA expression levels of type I collagen, Runx2 and Osterix in bone were suppressed by unloading in both wild-type mice and Tg mice. However, in contrast to unloading-induced enhancement of bone resorption parameters in wild-type mice, Col1a1-caPPR signaling suppressed, rather than enhanced, osteoclast number and osteoclast surface as well as urinary deoxypyridinoline excretion upon unloading. Col1a1-caPPR signaling also suppressed mRNA expression levels of RANK and c-fms in bone upon unloading. Although the M-CSF and monocyte chemoattractant protein 1 (MCP-1) mRNA levels were enhanced in control Tg mice, these levels were suppressed in unloaded Tg mice. These results indicated that constitutive activation of PTH/PTHrP receptor signaling in osteoblastic cells suppresses unloading-induced bone loss specifically through the regulation of osteoclastic activity. PMID:17500070

  7. miR-191 suppresses angiogenesis by activation of NF-κB signaling.

    Science.gov (United States)

    Gu, Yuan; Ampofo, Emmanuel; Menger, Michael D; Laschke, Matthias W

    2017-08-01

    MicroRNAs (miRNAs) are powerful regulators of diverse biologic processes. However, the function of most miRNAs in angiogenesis remains elusive. In this study, we identified miR-191-5p (miR-191) as a potent inhibitor of blood vessel development. Transfection of human dermal microvascular endothelial cells with miR-191 mimic (miR-191m) inhibited their proliferation, migration, and tube formation. Moreover, vascular sprouting of miR-191m-transfected mouse aortic rings was significantly reduced when compared with controls. Transfection with miR-191 inhibitor (miR-191i) induced proangiogenic effects. The anti- and proangiogenic activities of miR-191m and -191i were further demonstrated in vivo Additional molecular biologic analyses revealed that miR-191m activates NF-κB signaling by up-regulating the mRNA expression of p65. miR-191 also increased the mRNA levels of the antiangiogenic factors p21 and tissue inhibitor of metalloproteinase-1 and reduced the expression of the proangiogenic factors eNOS and matrix metalloproteinase-1 and -9. Blockade of NF-κB activation with Bay 11-7082 reversed the antiangiogenic effects of miR-191m. These findings indicate that miR-191 effectively suppresses angiogenesis by activation of the NF-κB signaling pathway.-Gu, Y., Ampofo, E., Menger, M. D., Laschke, M. W. miR-191 suppresses angiogenesis by activation of NF-κB signaling. © FASEB.

  8. Resveratrol suppresses IGF-1 induced human colon cancer cell proliferation and elevates apoptosis via suppression of IGF-1R/Wnt and activation of p53 signaling pathways

    Directory of Open Access Journals (Sweden)

    Radhakrishnan Sridhar

    2010-05-01

    Full Text Available Abstract Background Obesity is a global phenomenon and is associated with various types of cancer, including colon cancer. There is a growing interest for safe and effective bioactive compounds that suppress the risk for obesity-promoted colon cancer. Resveratrol (trans-3, 4', 5,-trihydroxystilbene, a stilbenoid found in the skin of red grapes and peanuts suppresses many types of cancers by regulating cell proliferation and apoptosis through a variety of mechanisms, however, resveratrol effects on obesity-promoted colon cancer are not clearly established. Methods We investigated the anti-proliferative effects of resveratrol on HT-29 and SW480 human colon cancer cells in the presence and absence of insulin like growth factor-1 (IGF-1; elevated during obesity and elucidated the mechanisms of action using IGF-1R siRNA in HT-29 cells which represents advanced colon carcinogenesis. Results Resveratrol (100-150 μM exhibited anti-proliferative properties in HT-29 cells even after IGF-1 exposure by arresting G0/G1-S phase cell cycle progression through p27 stimulation and cyclin D1 suppression. Treatment with resveratrol suppressed IGF-1R protein levels and concurrently attenuated the downstream Akt/Wnt signaling pathways that play a critical role in cell proliferation. Targeted suppression of IGF-1R using IGF-1R siRNA also affected these signaling pathways in a similar manner. Resveratrol treatment induced apoptosis by activating tumor suppressor p53 protein, whereas IGF-1R siRNA treatment did not affect apoptosis. Our data suggests that resveratrol not only suppresses cell proliferation by inhibiting IGF-1R and its downstream signaling pathways similar to that of IGF-1R siRNA but also enhances apoptosis via activation of the p53 pathway. Conclusions For the first time, we report that resveratrol suppresses colon cancer cell proliferation and elevates apoptosis even in the presence of IGF-1 via suppression of IGF-1R/Akt/Wnt signaling pathways and

  9. Resveratrol suppresses IGF-1 induced human colon cancer cell proliferation and elevates apoptosis via suppression of IGF-1R/Wnt and activation of p53 signaling pathways

    International Nuclear Information System (INIS)

    Vanamala, Jairam; Reddivari, Lavanya; Radhakrishnan, Sridhar; Tarver, Chris

    2010-01-01

    Obesity is a global phenomenon and is associated with various types of cancer, including colon cancer. There is a growing interest for safe and effective bioactive compounds that suppress the risk for obesity-promoted colon cancer. Resveratrol (trans-3, 4', 5,-trihydroxystilbene), a stilbenoid found in the skin of red grapes and peanuts suppresses many types of cancers by regulating cell proliferation and apoptosis through a variety of mechanisms, however, resveratrol effects on obesity-promoted colon cancer are not clearly established. We investigated the anti-proliferative effects of resveratrol on HT-29 and SW480 human colon cancer cells in the presence and absence of insulin like growth factor-1 (IGF-1; elevated during obesity) and elucidated the mechanisms of action using IGF-1R siRNA in HT-29 cells which represents advanced colon carcinogenesis. Resveratrol (100-150 μM) exhibited anti-proliferative properties in HT-29 cells even after IGF-1 exposure by arresting G 0 /G 1 -S phase cell cycle progression through p27 stimulation and cyclin D1 suppression. Treatment with resveratrol suppressed IGF-1R protein levels and concurrently attenuated the downstream Akt/Wnt signaling pathways that play a critical role in cell proliferation. Targeted suppression of IGF-1R using IGF-1R siRNA also affected these signaling pathways in a similar manner. Resveratrol treatment induced apoptosis by activating tumor suppressor p53 protein, whereas IGF-1R siRNA treatment did not affect apoptosis. Our data suggests that resveratrol not only suppresses cell proliferation by inhibiting IGF-1R and its downstream signaling pathways similar to that of IGF-1R siRNA but also enhances apoptosis via activation of the p53 pathway. For the first time, we report that resveratrol suppresses colon cancer cell proliferation and elevates apoptosis even in the presence of IGF-1 via suppression of IGF-1R/Akt/Wnt signaling pathways and activation of p53, suggesting its potential role as a

  10. BMAL1-dependent regulation of the mTOR signaling pathway delays aging.

    Science.gov (United States)

    Khapre, Rohini V; Kondratova, Anna A; Patel, Sonal; Dubrovsky, Yuliya; Wrobel, Michelle; Antoch, Marina P; Kondratov, Roman V

    2014-01-01

    The circadian clock, an internal time-keeping system, has been linked with control of aging, but molecular mechanisms of regulation are not known. BMAL1 is a transcriptional factor and core component of the circadian clock; BMAL1 deficiency is associated with premature aging and reduced lifespan. Here we report that activity of mammalian Target of Rapamycin Complex 1 (mTORC1) is increased upon BMAL1 deficiency both in vivo and in cell culture. Increased mTOR signaling is associated with accelerated aging; in accordance with that, treatment with the mTORC1 inhibitor rapamycin increased lifespan of Bmal1-/- mice by 50%. Our data suggest that BMAL1 is a negative regulator of mTORC1 signaling. We propose that the circadian clock controls the activity of the mTOR pathway through BMAL1-dependent mechanisms and this regulation is important for control of aging and metabolism.

  11. PFG-assisted selection and suppression of 1H NMR signals in the solid state under fast MAS

    Science.gov (United States)

    Fischbach, Ingrid; Thieme, Karena; Hoffmann, Anke; Hehn, Manfred; Schnell, Ingo

    2003-11-01

    Under fast MAS conditions, techniques for 1H signal selection and suppression, which have originally been developed for solution-state NMR, become applicable to solids. In this work, we describe how WATERGATE and DANTE pulse sequences can be used under MAS to selectively excite or suppress peaks in 1H solid-state spectra. As known from the liquid-state analogues, signal selection and/or suppression is supported by pulsed-field gradients which selectively dephase and rephase transverse magnetisation. Under MAS, the required field gradients are provided by a simple pair of coils which have been built into a standard fast-MAS probe. PFG-assisted techniques enable efficient selection or suppression of 1H peaks in a single transient of the pulse sequence without the need for phase cycles. Therefore, these tools can readily be incorporated into solid-state MAS NMR experiments, which is demonstrated here for 1H- 1H double-quantum NMR spectra of supramolecular systems. In the examples presented here, the 1H signals of interest are relatively weak and need to be observed despite the presence of the strong 1H signal of long alkyl sidechains. PFG-assisted suppression of this strong perturbing signal is shown to be particularly useful for obtaining unambiguous results.

  12. Suppression of STAT3 Signaling by Δ9-Tetrahydrocannabinol (THC) Induces Trophoblast Dysfunction.

    Science.gov (United States)

    Chang, Xinwen; Bian, Yiding; He, Qizhi; Yao, Julei; Zhu, Jingping; Wu, Jinting; Wang, Kai; Duan, Tao

    2017-01-01

    Marijuana is a widely used illicit drug and its consumption during pregnancy has been associated with adverse reproductive outcomes. The purpose of this study was to determine the effects of chronic intake of Δ9-tetrahydrocannabinol (THC), the major component of marijuana, on trophoblast function, placental development, and birth outcomes. The pathological characteristics and distribution of cannabinoid receptors in placenta were observed by immunohistochemical (IHC) staining. Cell migration in response to THC was measured by transwell assays. The levels of cannabinoid receptors and Signal Transducer and Activator of Transcription 3 (STAT3) were detected by western blot. We found the placenta expressed two main cannabinoid receptors, suggesting that THC induced biological responses in placental cells. Supporting this hypothesis, we observed dramatic alterations of placental morphology in marijuana users. Using THC and inhibitors of cannabinoid receptors, we demonstrated that THC impaired trophoblast cell migration and invasion partly via cannabinoid receptors. Additionally, pregnant mice injected with THC showed adverse reproductive events including reduced number of fetuses, lower maternal and placental weights. Mechanistically, STAT3 signaling pathway was involved in the THC-induced suppression of trophoblast cell motility and pregnancy outcomes. Our study indicates that the STAT3 signaling pathway plays a critical role in THC-induced trophoblast dysfunction. © 2017 The Author(s). Published by S. Karger AG, Basel.

  13. Suppression of STAT3 Signaling by Δ9-Tetrahydrocannabinol (THC Induces Trophoblast Dysfunction

    Directory of Open Access Journals (Sweden)

    Xinwen Chang

    2017-06-01

    Full Text Available Aims: Marijuana is a widely used illicit drug and its consumption during pregnancy has been associated with adverse reproductive outcomes. The purpose of this study was to determine the effects of chronic intake of Δ9-tetrahydrocannabinol (THC, the major component of marijuana, on trophoblast function, placental development, and birth outcomes. Methods: The pathological characteristics and distribution of cannabinoid receptors in placenta were observed by immunohistochemical (IHC staining. Cell migration in response to THC was measured by transwell assays. The levels of cannabinoid receptors and Signal Transducer and Activator of Transcription 3 (STAT3 were detected by western blot. Results: We found the placenta expressed two main cannabinoid receptors, suggesting that THC induced biological responses in placental cells. Supporting this hypothesis, we observed dramatic alterations of placental morphology in marijuana users. Using THC and inhibitors of cannabinoid receptors, we demonstrated that THC impaired trophoblast cell migration and invasion partly via cannabinoid receptors. Additionally, pregnant mice injected with THC showed adverse reproductive events including reduced number of fetuses, lower maternal and placental weights. Mechanistically, STAT3 signaling pathway was involved in the THC-induced suppression of trophoblast cell motility and pregnancy outcomes. Conclusion: Our study indicates that the STAT3 signaling pathway plays a critical role in THC-induced trophoblast dysfunction.

  14. Experimental Verification of the Fission Chamber Gamma Signal Suppression by the Campbelling Mode

    International Nuclear Information System (INIS)

    Vermeeren, L.; Weber, M.; Oriol, L.; Breaud, S.; Filliatre, P.; Geslot, B.; Jammes, C.; Normand, S.; Lescop, B.

    2011-01-01

    For the on-line monitoring of high fast neutron fluxes in the presence of a strong thermal neutron component, SCK-CEN and CEA are jointly developing a Fast Neutron Detector System, based on 242 Pu fission chambers as sensors and including dedicated electronics and data processing systems. Irradiation tests in the BR2 reactor of 242 Pu fission chambers operating in current mode showed that in typical MTR conditions the fission chamber currents are dominated by the gamma contribution. In order to reduce the gamma contribution to the signal, it was proposed to use the fission chambers in Campbelling mode. An irradiation experiment in the BR2 reactor with a 242 Pu and a 235 U fission chamber, both equipped with a suitable cable for measurements in Campbelling mode, proved the effectiveness of the suppression of the gamma-induced signal component by the Campbelling mode: gamma contribution reduction factors of 26 for the 235 U fission chamber and more than 80 for the 242 Pu fission chamber were obtained. The experimental data also prove that photofission contributions are negligibly small. Consequently, in typical MTR conditions the gamma contribution to the fission chamber Campbelling signal can be neglected. (authors)

  15. MR diffusion weighted imaging with background signal suppression in breast cancer

    International Nuclear Information System (INIS)

    Li Ming; Zhang Bing; Zhou Zhengyang; Yu Haiping; Yuan Lei; Zhu Bin

    2009-01-01

    Objective: To explore the feasibility of echo planar imaging with short time inversion recovery (STIR-EPI) diffusion weighted imaging with background signal (DWIBS) suppression in breast cancer. Methods: The diffusion weighted imaging (DWI)with background suppression (b=800 mm 2 /s) was performed in 26 patients with breast cancer. Apparent diffusion coefficient(ADC) of all lesions were measured and compared. 3D maximum intensity projection (3D-MIP)and reverse black and white technique were used to show the lesions. DWI and DWIBS were performed and compared for the detection of breast cancer. Randomized blocks analysis of variance was used for the ADC values in different breast tissues, the ADC values in breast cancer and benign lesion were compared using t test. The paired chi square test was used for the detection rate of breast cancer in two different imaging methods. Results: Most of the breast cancers were hyperintense on DWI (b=800 mm 2 /s). The ADC value of cancer tissue was (0.93±0.25) x 10 -3 mm 2 /s, tumor necrosis was (2.06±0.17) x 10 -3 mm 2 /s, normal breast tissue was (1.92±0.23) x 10 -3 mm 2 /s and metastatic lymph node was (1.10±0.14) x 10 -3 mm 2 /s and the differences were statistically significant between two structures (P 2 =8.307, P 2 = 12.235, P -3 mm 2 /s and benign lesion (2.15±0.53) x 10 -3 mm 2 /s had significant statistical differences (t=8.626,P<0.05). Conclusion: Diffusion weighted MRI with background suppression can detect more lesions than DWI and can be potentially applied for the detection of the breast cancer combining the ADC value. (authors)

  16. P2X7R suppression promotes glioma growth through epidermal growth factor receptor signal pathway.

    Science.gov (United States)

    Fang, Jingqin; Chen, Xiao; Zhang, Letian; Chen, Jinhua; Liang, Yi; Li, Xue; Xiang, Jianbo; Wang, Lili; Guo, Guangkuo; Zhang, Bo; Zhang, Weiguo

    2013-06-01

    P2X7 receptor (P2X7R) has been shown to mediate an anticancer effect via apoptosis in different types of cancer. However, whether P2X7R exerts a promoting or suppressive effect on brain glioma is still a controversial issue and its underlying mechanism remains unknown. We showed here that P2X7R suppression exerted a pro-growth effect on glioma through directly promoting cells proliferation and pro-angiogenesis, which was associated with epidermal growth factor receptor (EGFR) signaling. The P2X7R was markedly downregulated by cells exposure to the P2X7R antagonist, brilliant blue G (BBG), moreover, the cells proliferation was enhanced in a dose-dependent manner and the expression of EGFR or p-EGFR protein was significantly upregulated. By constructing C6 cells with reduced expression of P2X7R using shRNA, we also demonstrated strong upregulation in cells proliferation and EGFR/p-EGFR expression. However, this effect of BBG was reversed in the presence of gefitinib or suramin. Magnetic resonance imaging and computed tomography perfusion showed that the BBG or P2X7R shRNA promoted the tumor growth by about 40% and 50%, respectively, and significantly increased angiogenesis. Nissl and Ki-67 staining also confirmed that BBG or P2X7R shRNA notably increased the tumor growth. More importantly, either BBG or P2X7R shRNA could markedly upregulated the expression of EGFR, p-EGFR, HIF-1α and VEGF in glioma cells. In conclusion, P2X7R suppression exerts a promoting effect on glioma growth, which is likely to be related to upregulated EGFR, HIF-1α and VEGF expression. These findings provide important clues to the molecular basis of anticancer effect of targeting purinergic receptors. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Melatonin attenuated brain death tissue extract-induced cardiac damage by suppressing DAMP signaling.

    Science.gov (United States)

    Sung, Pei-Hsun; Lee, Fan-Yen; Lin, Ling-Chun; Chen, Kuan-Hung; Lin, Hung-Sheng; Shao, Pei-Lin; Li, Yi-Chen; Chen, Yi-Ling; Lin, Kun-Chen; Yuen, Chun-Man; Chang, Hsueh-Wen; Lee, Mel S; Yip, Hon-Kan

    2018-01-09

    We tested the hypothesis that melatonin prevents brain death (BD) tissue extract (BDEX)-induced cardiac damage by suppressing inflammatory damage-associated molecular pattern (DAMP) signaling in rats. Six hours after BD induction, levels of a DAMP component (HMGB1) and inflammatory markers (TLR-2, TLR-4, MYD88, IκB, NF-κB, IL-1β, IFN-γ, TNF-α and IL-6) were higher in brain tissue from BD animals than controls. Levels of HMGB1 and inflammatory markers were higher in BDEX-treated H9C2 cardiac myoblasts than in cells treated with healthy brain tissue extract. These increases were attenuated by melatonin but re-induced with luzindole (all P DAMP inflammatory axis.

  18. Excessive Leucine-mTORC1-Signalling of Cow Milk-Based Infant Formula: The Missing Link to Understand Early Childhood Obesity

    Science.gov (United States)

    Melnik, Bodo C.

    2012-01-01

    Increased protein supply by feeding cow-milk-based infant formula in comparison to lower protein content of human milk is a well-recognized major risk factor of childhood obesity. However, there is yet no conclusive biochemical concept explaining the mechanisms of formula-induced childhood obesity. It is the intention of this article to provide the biochemical link between leucine-mediated signalling of mammalian milk proteins and adipogenesis as well as early adipogenic programming. Leucine has been identified as the predominant signal transducer of mammalian milk, which stimulates the nutrient-sensitive kinase mammalian target of rapamycin complex 1 (mTORC1). Leucine thus functions as a maternal-neonatal relay for mTORC1-dependent neonatal β-cell proliferation and insulin secretion. The mTORC1 target S6K1 plays a pivotal role in stimulation of mesenchymal stem cells to differentiate into adipocytes and to induce insulin resistance. It is of most critical concern that infant formulas provide higher amounts of leucine in comparison to human milk. Exaggerated leucine-mediated mTORC1-S6K1 signalling induced by infant formulas may thus explain increased adipogenesis and generation of lifelong elevated adipocyte numbers. Attenuation of mTORC1 signalling of infant formula by leucine restriction to physiologic lower levels of human milk offers a great chance for the prevention of childhood obesity and obesity-related metabolic diseases. PMID:22523661

  19. Excessive Leucine-mTORC1-Signalling of Cow Milk-Based Infant Formula: The Missing Link to Understand Early Childhood Obesity

    Directory of Open Access Journals (Sweden)

    Bodo C. Melnik

    2012-01-01

    Full Text Available Increased protein supply by feeding cow-milk-based infant formula in comparison to lower protein content of human milk is a well-recognized major risk factor of childhood obesity. However, there is yet no conclusive biochemical concept explaining the mechanisms of formula-induced childhood obesity. It is the intention of this article to provide the biochemical link between leucine-mediated signalling of mammalian milk proteins and adipogenesis as well as early adipogenic programming. Leucine has been identified as the predominant signal transducer of mammalian milk, which stimulates the nutrient-sensitive kinase mammalian target of rapamycin complex 1 (mTORC1. Leucine thus functions as a maternal-neonatal relay for mTORC1-dependent neonatal β-cell proliferation and insulin secretion. The mTORC1 target S6K1 plays a pivotal role in stimulation of mesenchymal stem cells to differentiate into adipocytes and to induce insulin resistance. It is of most critical concern that infant formulas provide higher amounts of leucine in comparison to human milk. Exaggerated leucine-mediated mTORC1-S6K1 signalling induced by infant formulas may thus explain increased adipogenesis and generation of lifelong elevated adipocyte numbers. Attenuation of mTORC1 signalling of infant formula by leucine restriction to physiologic lower levels of human milk offers a great chance for the prevention of childhood obesity and obesity-related metabolic diseases.

  20. ABA signalling manipulation suppresses senescence of a leafy vegetable stored at room temperature.

    Science.gov (United States)

    Miret, Javier A; Munné-Bosch, Sergi; Dijkwel, Paul P

    2018-02-01

    Postharvest senescence and associated stresses limit the shelf life and nutritional value of vegetables. Improved understanding of these processes creates options for better management. After harvest, controlled exposure to abiotic stresses and/or exogenous phytohormones can enhance nutraceutical, organoleptic and commercial longevity traits. With leaf senescence, abscisic acid (ABA) contents progressively rise, but the actual biological functions of this hormone through senescence still need to be clarified. Postharvest senescence of detached green cabbage leaves (Brassica oleracea var. capitata) was characterized under cold (4 °C) and room temperature (25 °C) storage conditions. Hormonal profiling of regions of the leaf blade (apical, medial, basal) revealed a decrease in cytokinins contents during the first days under both conditions, while ABA only increased at 25 °C. Treatments with ABA and a partial agonist of ABA (pyrabactin) for 8 days did not lead to significant effects on water and pigment contents, but increased cell integrity and altered 1-aminocyclopropane-1-carboxylic acid (ACC) and cytokinins contents. Transcriptome analysis showed transcriptional regulation of ABA, cytokinin and ethylene metabolism and signalling; proteasome components; senescence regulation; protection of chloroplast functionality and cell homeostasis; and suppression of defence responses (including glucosinolates and phenylpropanoids metabolism). It is concluded that increasing the concentration of ABA (or its partial agonist pyrabactin) from the start of postharvest suppresses senescence of stored leaves, changes the transcriptional regulation of glucosinolates metabolism and down-regulates biotic stress defence mechanisms. These results suggest a potential for manipulating ABA signalling for improving postharvest quality of leafy vegetables stored at ambient temperature. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The

  1. Ski regulates Hippo and TAZ signaling to suppress breast cancer progression.

    Science.gov (United States)

    Rashidian, Juliet; Le Scolan, Erwan; Ji, Xiaodan; Zhu, Qingwei; Mulvihill, Melinda M; Nomura, Daniel; Luo, Kunxin

    2015-02-10

    Ski, the transforming protein of the avian Sloan-Kettering retrovirus, inhibits transforming growth factor-β (TGF-β)/Smad signaling and displays both pro-oncogenic and anti-oncogenic activities in human cancer. Inhibition of TGF-β signaling is likely responsible for the pro-oncogenic activity of Ski. We investigated the mechanism(s) underlying the tumor suppressor activity of Ski and found that Ski suppressed the activity of the Hippo signaling effectors TAZ and YAP to inhibit breast cancer progression. TAZ and YAP are transcriptional coactivators that can contribute to cancer by promoting proliferation, tumorigenesis, and cancer stem cell expansion. Hippo signaling activates the the Lats family of kinases, which phosphorylate TAZ and YAP, resulting in cytoplasmic retention and degradation and inhibition of their transcriptional activity. We showed that Ski interacted with multiple components of the Hippo pathway to facilitate activation of Lats2, resulting in increased phosphorylation and subsequent degradation of TAZ. Ski also promoted the degradation of a constitutively active TAZ mutant that is not phosphorylated by Lats, suggesting the existence of a Lats2-independent degradation pathway. Finally, we showed that Ski repressed the transcriptional activity of TAZ by binding to the TAZ partner TEAD and recruiting the transcriptional co-repressor NCoR1 to the TEAD-TAZ complex. Ski effectively reversed transformation and epithelial-to-mesenchyme transition in cultured breast cancer cells and metastasis in TAZ-expressing xenografted tumors. Thus, Ski inhibited the function of TAZ through multiple mechanisms in human cancer cells. Copyright © 2015, American Association for the Advancement of Science.

  2. Toosendanin induces apoptosis through suppression of JNK signaling pathway in HL-60 cells.

    Science.gov (United States)

    Ju, Jianming; Qi, Zhichao; Cai, Xueting; Cao, Peng; Liu, Nan; Wang, Shuzhen; Chen, Yijun

    2013-02-01

    Toosendanin (TSN), a triterpenoid isolated from Melia toosendan Sieb. et Zucc., has been found to suppress proliferation and induce apoptosis in a variety of human cancer cells. However, the mechanism how TSN induces apoptosis remains poorly understood. In this study, we examined the effects of TSN on the growth, cell cycle arrest, induction of apoptosis and the involved signaling pathway in human promyelocytic leukemia HL-60 cells. Proliferation of HL-60 cells was inhibited in a dose-dependent manner with the IC(50 (48 h)) of 28 ng/mL. The growth inhibition was due primarily to the S phase arrest and cell apoptosis. Cell apoptosis induced by TSN was confirmed by Annexin V-FITC/propidium iodide staining. The increase of the pro-apoptotic protein Bax, cleaved PARP and caspase-3, and the decrease of anti-apoptotic protein Bcl-2 were observed. Western blot analysis indicated that TSN inhibits the CDC42/MEKK1/JNK pathway. Taken together, our study suggested, for the first time, that the pro-apoptotic effects of TSN on HL-60 cells were mediated through JNK signaling pathway. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Entada phaseoloides extract suppresses hepatic gluconeogenesis via activation of the AMPK signaling pathway.

    Science.gov (United States)

    Zheng, Tao; Hao, Xincai; Wang, Qibin; Chen, Li; Jin, Si; Bian, Fang

    2016-12-04

    The seed of Entada phaseoloides (L.) Merr. (Entada phaseoloides) has been long used as a folk medicine for the treatment of Diabetes mellitus by Chinese ethnic minorities. Recent reports have demonstrated that total saponins from Entada phaseoloides (TSEP) could reduce fasting blood glucose in type 2 diabetic rats. However, the mechanism has not been fully elucidated. The aim of this study was to explore the underlying mechanisms of TSEP on type 2 Diabetes mellitus (T2DM). Primary mouse hepatocytes and HepG2 cells were used to investigate the effects of TSEP on gluconeogenesis. After treatment with TSEP, glucose production, genes expression levels of Glucose-6-phosphatase (G6pase) and Phosphoenoylpyruvate carboxykinase (Pepck) were detected. The efficacy and underlying mechanism of TSEP on AMP-activated protein kinase (AMPK) signaling pathway were determinated. TSEP significantly inhibited glucose production and the gluconeogenic gene expression. Treatment with TSEP elevated the phosphorylation of AMPK, which in turn promoted the phosphorylation of acetyl coenzyme A (ACC) and Akt/glycogen synthase kinase 3β (GSK3β), respectively. Furthermore, TSEP reduced lipid accumulation and improved insulin sensitivity in hepatocytes. These findings provide evidence that TSEP exerts an antidiabetic effect by suppressing hepatic gluconeogenesis via the AMPK signaling pathway. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  4. Dirac Gauginos in Supersymmetry -- Suppressed Jets + MET Signals: A Snowmass Whitepaper

    CERN Document Server

    Kribs, Graham D.

    2013-01-01

    We consider the modifications to squark production in the presence of a naturally heavier Dirac gluino. First generation squark production is highly suppressed, providing an interesting but challenging signal find or rule out. No dedicated searches for supersymmetry with a Dirac gluino have been performed, however a reinterpretation of a "decoupled gluino" simplified model suggests the bounds on a common first and second generation squark mass is much smaller than in the MSSM: $\\lsim 850$ GeV for a massless LSP, and no bound for an LSP heavier than about 300 GeV. We compare and contrast the squark production cross sections between a model with a Dirac gluino and one with a Majorana gluino, updating earlier results in the literature to a $pp$ collider operating at $\\sqrt{s} = 14$ and 33 TeV. Associated production of squark+gluino is likely very small at $\\sqrt{s} = 14$ TeV, while is a challenging but important signal at even higher energy $pp$ colliders. Several other salient implications of Dirac gauginos are...

  5. A silyl andrographolide analogue suppresses Wnt/β-catenin signaling pathway in colon cancer.

    Science.gov (United States)

    Reabroi, Somrudee; Chairoungdua, Arthit; Saeeng, Rungnapha; Kasemsuk, Teerapich; Saengsawang, Witchuda; Zhu, Weiming; Piyachaturawat, Pawinee

    2018-05-01

    Hyperactivation of Wnt/β-catenin signaling implicated in oncogenesis of colorectal cancer (CRC) is a potential molecular target for chemotherapy. An andrographolide analogue, 3A.1 (19-tert-butyldiphenylsilyl-8, 17-epoxy andrographolide) has previously been reported to be potently cytotoxic toward cancer cells by unknown molecular mechanisms. The present study explored the anti-cancer activity of analogue 3A.1 on Wnt/β-catenin signaling in colon cancer cells (HT29 cells) which were more sensitive to the others (HCT116 and SW480 cells). Analogue 3A.1 inhibited viability of HT29 cells with IC 50 value of 11.1 ± 1.4 μM at 24 h, which was more potent than that of the parent andrographolide. Analogue 3A.1 also suppressed the proliferation of HT29 cells and induced cell apoptosis in a dose-dependent manner. Its apoptotic activity was accompanied with increased expressions of proteins related to DNA damages; PARP-1 and γ-H2AX. In addition, analogue 3A.1 significantly inhibited T-cell factor and lymphoid enhancer factor (TCF/LEF) promoter activity of Wnt/β-catenin signaling. Accordingly, the expressions of Wnt target genes and β-catenin protein were suppressed. Moreover, analogue 3A.1 increased the activity of GSK-3β kinase, which is a negative regulator responsible for degradation of intracellular β-catenin. This mode of action was further supported by the absence of the effects after treatment with a GSK-3β inhibitor, and over-expression of a mutant β-catenin (S33Y). Our findings reveal, for the first time, an insight into the molecular mechanism of the anti-cancer activity of analogue 3A.1 through the inhibition of Wnt/β-catenin/GSK-3β pathway and provide a therapeutic potential of the andrographolide analogue 3A.1 in CRC treatment. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  6. Cyclin G2 suppresses estrogen-mediated osteogenesis through inhibition of Wnt/β-catenin signaling.

    Directory of Open Access Journals (Sweden)

    Jinlan Gao

    Full Text Available Estrogen plays an important role in the maintenance of bone formation, and deficiency in the production of estrogen is directly linked to postmenopausal osteoporosis. To date, the underlying mechanisms of estrogen-mediated osteogenic differentiation are not well understood. In this study, a pluripotent mesenchymal precursor cell line C2C12 was used to induce osteogenic differentiation and subjected to detection of gene expressions or to manipulation of cyclin G2 expressions. C57BL/6 mice were used to generate bilateral ovariectomized and sham-operated mice for analysis of bone mineral density and protein expression. We identified cyclin G2, an unconventional member of cyclin, is involved in osteoblast differentiation regulated by estrogen in vivo and in vitro. In addition, the data showed that ectopic expression of cyclin G2 suppressed expression of osteoblast transcription factor Runx2 and osteogenic differentiation marker genes, as well as ALP activity and in vitro extracellular matrix mineralization. Mechanistically, Wnt/β-catenin signaling pathway is essential for cyclin G2 to inhibit osteogenic differentiation. To the best of our knowledge, the current study presents the first evidence that cyclin G2 serves as a negative regulator of both osteogenesis and Wnt/β-catenin signaling. Most importantly, the basal and 17β-estradiol-induced osteogenic differentiation was restored by overexpression of cyclin G2. These results taken together suggest that cyclin G2 may function as an endogenous suppressor of estrogen-induced osteogenic differentiation through inhibition of Wnt/β-catenin signaling.

  7. Suppression of phase-induced intensity noise in fibre optic delay line signal processors using an optical phase modulation technique.

    Science.gov (United States)

    Chan, Erwin H W

    2010-10-11

    A technique that can suppress the dominant phase-induced intensity noise in fibre optic delay line signal processors is presented. It is based on phase modulation of the optical carrier to distribute the phase noise at the information band into a high frequency band which can be filtered out. This technique is suitable for suppressing the phase noise in various delay line structures and for integrating in the conventional fibre optic links. It can also suppress the coherent interference effect at the same time. A model for predicting the amount of phase noise reduction in various delay line structures using the optical phase modulation technique is presented for the first time and is experimentally verified. Experimental results demonstrate the technique can achieve a large phase noise reduction in various fibre optic delay line signal processors.

  8. Suppressed hepatic bile acid signalling despite elevated production of primary and secondary bile acids in NAFLD.

    Science.gov (United States)

    Jiao, Na; Baker, Susan S; Chapa-Rodriguez, Adrian; Liu, Wensheng; Nugent, Colleen A; Tsompana, Maria; Mastrandrea, Lucy; Buck, Michael J; Baker, Robert D; Genco, Robert J; Zhu, Ruixin; Zhu, Lixin

    2017-08-03

    Bile acids are regulators of lipid and glucose metabolism, and modulate inflammation in the liver and other tissues. Primary bile acids such as cholic acid and chenodeoxycholic acid (CDCA) are produced in the liver, and converted into secondary bile acids such as deoxycholic acid (DCA) and lithocholic acid by gut microbiota. Here we investigated the possible roles of bile acids in non-alcoholic fatty liver disease (NAFLD) pathogenesis and the impact of the gut microbiome on bile acid signalling in NAFLD. Serum bile acid levels and fibroblast growth factor 19 (FGF19), liver gene expression profiles and gut microbiome compositions were determined in patients with NAFLD, high-fat diet-fed rats and their controls. Serum concentrations of primary and secondary bile acids were increased in patients with NAFLD. In per cent, the farnesoid X receptor (FXR) antagonistic DCA was increased, while the agonistic CDCA was decreased in NAFLD. Increased mRNA expression for cytochrome P450 7A1, Na + -taurocholate cotransporting polypeptide and paraoxonase 1, no change in mRNA expression for small heterodimer partner and bile salt export pump, and reduced serum FGF19 were evidence of impaired FXR and fibroblast growth factor receptor 4 (FGFR4)-mediated signalling in NAFLD. Taurine and glycine metabolising bacteria were increased in the gut of patients with NAFLD, reflecting increased secondary bile acid production. Similar changes in liver gene expression and the gut microbiome were observed in high-fat diet-fed rats. The serum bile acid profile, the hepatic gene expression pattern and the gut microbiome composition consistently support an elevated bile acid production in NAFLD. The increased proportion of FXR antagonistic bile acid explains, at least in part, the suppression of hepatic FXR-mediated and FGFR4-mediated signalling. Our study suggests that future NAFLD intervention may target the components of FXR signalling, including the bile acid converting gut microbiome. © Article

  9. Insulin Signaling in Type 2 Diabetes

    Science.gov (United States)

    Brännmark, Cecilia; Nyman, Elin; Fagerholm, Siri; Bergenholm, Linnéa; Ekstrand, Eva-Maria; Cedersund, Gunnar; Strålfors, Peter

    2013-01-01

    Type 2 diabetes originates in an expanding adipose tissue that for unknown reasons becomes insulin resistant. Insulin resistance reflects impairments in insulin signaling, but mechanisms involved are unclear because current research is fragmented. We report a systems level mechanistic understanding of insulin resistance, using systems wide and internally consistent data from human adipocytes. Based on quantitative steady-state and dynamic time course data on signaling intermediaries, normally and in diabetes, we developed a dynamic mathematical model of insulin signaling. The model structure and parameters are identical in the normal and diabetic states of the model, except for three parameters that change in diabetes: (i) reduced concentration of insulin receptor, (ii) reduced concentration of insulin-regulated glucose transporter GLUT4, and (iii) changed feedback from mammalian target of rapamycin in complex with raptor (mTORC1). Modeling reveals that at the core of insulin resistance in human adipocytes is attenuation of a positive feedback from mTORC1 to the insulin receptor substrate-1, which explains reduced sensitivity and signal strength throughout the signaling network. Model simulations with inhibition of mTORC1 are comparable with experimental data on inhibition of mTORC1 using rapamycin in human adipocytes. We demonstrate the potential of the model for identification of drug targets, e.g. increasing the feedback restores insulin signaling, both at the cellular level and, using a multilevel model, at the whole body level. Our findings suggest that insulin resistance in an expanded adipose tissue results from cell growth restriction to prevent cell necrosis. PMID:23400783

  10. Screening of Kit inhibitors: suppression of Kit signaling and melanogenesis by emodin.

    Science.gov (United States)

    Lee, Seong Jin; Jeong, Daeyoung; Park, Woo-Kyu; Kong, Jae Yang; Choi, Gildon; Kim, Hojeong; Kang, Sangjin; Cho, Heeyeong

    2010-02-01

    In search of novel antipigmentation agents, a set of 3,840 compounds with natural-like synthetic or natural origin were screened against Kit (stem cell factor receptor). Emodin from the seed of Cassia tora and baicalin from Scutellariae radix showed potent inhibitory effects (IC(50) = 4.9 and 9.0 microM, respectively) on the phosphorylation of Kit. Emodin also blocked other receptor tyrosine kinase activities, such as epithelial growth factor receptor (EGFR), vascular endothelial growth factor receptor 2 (VEGFR-2), fibroblast growth factor receptor 1 (FGFR-1), platelet-derived growth factor receptor b (PDGFR-b). In contrast to emodin, aloe-emodin did not inhibit Kit activity at all. Emodin also blocked the cellular kinase activities of Kit and its down-stream p44/42 mitogen activated protein kinase (MAPK) in MO7e cells and human primary melanocytes. Emodin strongly suppressed the melanin synthesis triggered by stem cell factor (SCF) treatment. Also, emodin showed almost no toxicity up to 10 microM on cultured melanocytes as reported previously by other researchers. The results indicate that emodin is a good candidate for the development of antipigmentation agents since it can radically block the differentiation and proliferation of pigment cells by reducing Kit signaling. (c) 2009 John Wiley & Sons, Ltd.

  11. Small molecule inhibitor regorafenib inhibits RET signaling in neuroblastoma cells and effectively suppresses tumor growthin vivo.

    Science.gov (United States)

    Chen, Zhenghu; Zhao, Yanling; Yu, Yang; Pang, Jonathan C; Woodfield, Sarah E; Tao, Ling; Guan, Shan; Zhang, Huiyuan; Bieerkehazhi, Shayahati; Shi, Yan; Patel, Roma; Vasudevan, Sanjeev A; Yi, Joanna S; Muscal, Jodi A; Xu, Guo-Tong; Yang, Jianhua

    2017-11-28

    Neuroblastoma (NB), the most common extracranial pediatric solid tumor, continues to cause significant cancer-related morbidity and mortality in children. Dysregulation of oncogenic receptor tyrosine kinases (RTKs) has been shown to contribute to tumorigenesis in various human cancers and targeting these RTKs has had therapeutic benefit. RET is an RTK which is commonly expressed in NB, and high expression of RET correlates with poor outcomes in patients with NB. Herein we report that RET is required for NB cell proliferation and that the small molecule inhibitor regorafenib (BAY 73-4506) blocks glial cell derived neurotrophic factor (GDNF)-induced RET signaling in NB cells and inhibits NB growth both in vitro and in vivo . We found that regorafenib significantly inhibited cell proliferation and colony formation ability of NB cells. Moreover, regorafenib suppressed tumor growth in both an orthotopic xenograft NB mouse model and a TH-MYCN transgenic NB mouse model. Finally, regorafenib markedly improved the overall survival of TH-MYCN transgenic tumor-bearing mice. In summary, our study suggests that RET is a potential therapeutic target in NB, and that using a novel RET inhibitor, like regorafenib, should be investigated as a therapeutic treatment option for children with NB.

  12. NPY Signaling Inhibits Extended Amygdala CRF Neurons to Suppress Binge Alcohol Drinking

    Science.gov (United States)

    Pleil, Kristen E.; Rinker, Jennifer A.; Lowery-Gionta, Emily G.; Mazzone, Christopher M.; McCall, Nora M.; Kendra, Alexis M.; Olson, David P.; Lowell, Bradford B.; Grant, Kathleen A.; Thiele, Todd E.; Kash, Thomas L.

    2015-01-01

    Summary paragraph Binge alcohol drinking is a tremendous public health problem because it leads to the development of numerous pathologies including alcohol abuse, and anxiety1–4. It is thought to do so by hijacking brain systems that regulate stress and reward, including neuropeptide Y (NPY) and corticotropin–releasing factor (CRF). The central actions of NPY and CRF play opposing functional roles in the regulation of emotional and reward–seeking behaviors; therefore, dysfunctional interactions between these peptidergic systems could play a role in the development of these pathologies. Here, we used converging physiological, pharmacological, and chemogenetic approaches to identify a precise neural mechanism in the bed nucleus of the stria terminalis (BNST), a limbic brain region involved in pathological reward and anxiety behaviors, underlying the interactions between NPY and CRF in the regulation of binge alcohol drinking in both mice and monkeys. We found that NPY Y1 receptor (Y1R) activation in the BNST suppressed binge alcohol drinking by enhancing inhibitory synaptic transmission specifically in CRF neurons via a novel, Gi-mediated, PKA-dependent postsynaptic mechanism. Further, chronic alcohol drinking led to persistent alterations in Y1R function in the BNST of both mice and monkeys, highlighting the enduring, conserved nature of this effect across mammalian species. Together, these data provide both a cellular locus and signaling framework for the development of novel therapeutics for treatment of neuropsychiatric diseases, including alcohol use disorders. PMID:25751534

  13. Butyrylcholinesterase gene transfer in obese mice prevents postdieting body weight rebound by suppressing ghrelin signaling.

    Science.gov (United States)

    Chen, Vicky Ping; Gao, Yang; Geng, Liyi; Brimijoin, Stephen

    2017-10-10

    The worldwide prevalence of obesity is increasing at an alarming rate but treatment options remain limited. Despite initial success, weight loss by calorie restriction (CR) often fails because of rebound weight gain. Postdieting hyperphagia along with altered hypothalamic neuro-architecture appears to be one direct cause of this undesirable outcome. In response to calorie deficiency the circulating levels of the appetite-promoting hormone, acyl-ghrelin, rise sharply. We hypothesize that proper modulation of acyl-ghrelin and its receptor's sensitivity will favorably impact energy intake and reprogram the body weight set point. Here we applied viral gene transfer of the acyl-ghrelin hydrolyzing enzyme, butyrylcholinesterase (BChE), in a mouse model of diet-induced obesity. Our results confirmed that BChE overexpression decreased circulating acyl-ghrelin levels, suppressed CR-provoked ghrelin signaling, and restored central ghrelin sensitivity. In addition to maintaining healthy body weights, BChE treated mice had modest postdieting food intake and showed normal glucose homeostasis. Spontaneous activity and energy expenditure did not differ significantly between treated and untreated mice after body weight rebound, suggesting that BChE gene transfer did not alter energy expenditure in the long term. These findings indicate that combining BChE treatment with CR could be an effective approach in treating human obesity and aiding lifelong weight management.

  14. Pristimerin overcomes adriamycin resistance in breast cancer cells through suppressing Akt signaling

    Science.gov (United States)

    XIE, GUI'E; YU, XINPEI; LIANG, HUICHAO; CHEN, JINGSONG; TANG, XUEWEI; WU, SHAOQING; LIAO, CAN

    2016-01-01

    Breast cancer remains a major public health problem worldwide. Chemotherapy serves an important role in the treatment of breast cancer. However, resistance to chemotherapeutic agents, in particular, multi-drug resistance (MDR), is a major cause of treatment failure in cancer. Agents that can either enhance the effects of chemotherapeutics or overcome chemoresistance are urgently needed for the treatment of breast cancer. Pristimerin, a quinonemethide triterpenoid compound isolated from Celastraceae and Hippocrateaceae, has been shown to possess antitumor, anti-inflammatory, antioxidant and insecticidal properties. The aim of the present study was to investigate whether pristimerin can override chemoresistance in MCF-7/adriamycin (ADR)-resistant human breast cancer cells. The results demonstrated that pristimerin indeed displayed potent cytocidal effect on multidrug-resistant MCF-7/ADR breast cancer cells, and that these effects occurred through the suppression of Akt signaling, which in turn led to the downregulation of antiapoptotic effectors and increased apoptosis. These findings indicate that use of pristimerin may represent a potentially promising approach for the treatment of ADR-resistant breast cancer. PMID:27123073

  15. Enhanced skeletal muscle ribosome biogenesis, yet attenuated mTORC1 and ribosome biogenesis-related signalling, following short-term concurrent versus single-mode resistance training

    OpenAIRE

    Fyfe, Jackson J.; Bishop, David J.; Bartlett, Jonathan D.; Hanson, Erik D.; Anderson, Mitchell J.; Garnham, Andrew P.; Stepto, Nigel K.

    2018-01-01

    Combining endurance training with resistance training (RT) may attenuate skeletal muscle hypertrophic adaptation versus RT alone; however, the underlying mechanisms are unclear. We investigated changes in markers of ribosome biogenesis, a process linked with skeletal muscle hypertrophy, following concurrent training versus RT alone. Twenty-three males underwent eight weeks of RT, either performed alone (RT group, n = 8), or combined with either high-intensity interval training (HIT+RT group, ...

  16. A new phase modulated binomial-like selective-inversion sequence for solvent signal suppression in NMR.

    Science.gov (United States)

    Chen, Johnny; Zheng, Gang; Price, William S

    2017-02-01

    A new 8-pulse Phase Modulated binomial-like selective inversion pulse sequence, dubbed '8PM', was developed by optimizing the nutation and phase angles of the constituent radio-frequency pulses so that the inversion profile resembled a target profile. Suppression profiles were obtained for both the 8PM and W5 based excitation sculpting sequences with equal inter-pulse delays. Significant distortions were observed in both profiles because of the offset effect of the radio frequency pulses. These distortions were successfully reduced by adjusting the inter-pulse delays. With adjusted inter-pulse delays, the 8PM and W5 based excitation sculpting sequences were tested on an aqueous lysozyme solution. The 8 PM based sequence provided higher suppression selectivity than the W5 based sequence. Two-dimensional nuclear Overhauser effect spectroscopy experiments were also performed on the lysozyme sample with 8PM and W5 based water signal suppression. The 8PM based suppression provided a spectrum with significantly increased (~ doubled) cross-peak intensity around the suppressed water resonance compared to the W5 based suppression. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  17. System for the suppression of noise and of noise fluctuations: extraction of a net signal from another one containing frequencies of noise and discontinuous signal

    International Nuclear Information System (INIS)

    Rambaut, M.

    1989-01-01

    A patent is claimed for an invention relating to a system for the suppression of noise and noise fluctuations. The aim of the system is the detection of the signal contained in noise-and-discontinuous signal mixed frequencies. The invention is to be applied in radiation detection. The results of the measurements are reliable for short counting rates, as compared with the time constant of the background noise fluctuations, and for measurements performed in regions having the same background noise average. The diagram, the characteristics and the operation of the invention are described [fr

  18. Quercetin suppresses insulin receptor signaling through inhibition of the insulin ligand–receptor binding and therefore impairs cancer cell proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Feng [Department of Gastroenterology, The Tenth People’s Hospital of Shanghai, Tongji University, Shanghai 200072 (China); Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030 (United States); Yang, Yong, E-mail: yyang@houstonmethodist.org [Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030 (United States); Department of Medicine, Weill Cornell Medical College, New York, NY 10065 (United States)

    2014-10-03

    Graphical abstract: - Highlights: • Quercetin inhibits insulin ligand–receptor interactions. • Quercetin reduces downstream insulin receptor signaling. • Quercetin blocks insulin induced glucose uptake. • Quercetin suppresses insulin stimulated cancer cell proliferation and tumor growth. - Abstract: Although the flavonoid quercetin is known to inhibit activation of insulin receptor signaling, the inhibitory mechanism is largely unknown. In this study, we demonstrate that quercetin suppresses insulin induced dimerization of the insulin receptor (IR) through interfering with ligand–receptor interactions, which reduces the phosphorylation of IR and Akt. This inhibitory effect further inhibits insulin stimulated glucose uptake due to decreased cell membrane translocation of glucose transporter 4 (GLUT4), resulting in impaired cancer cell proliferation. The effect of quercetin in inhibiting tumor growth was also evident in an in vivo model, indicating a potential future application for quercetin in the treatment of cancers.

  19. Bulleyaconitine A prevents Ti particle-induced osteolysis via suppressing NF-κB signal pathway during osteoclastogenesis and osteoblastogenesis.

    Science.gov (United States)

    Zhang, Liwei; Feng, Mingxuan; Li, Zhiyan; Zhu, Min; Fan, Yongyong; Chu, Binxiang; Yuan, Chiting; Chen, Lihua; Lv, Haiyan; Hong, Zhenghua; Hong, Dun

    2018-02-01

    Balanced bone resorption and bone formation are vital for bone homeostasis. Excessive osteoclastic bone resorption in this process can cause a variety of bone disorders including osteoporosis, aseptic prosthetic loosening and tumor associated bone destruction. Bulleyaconitine A (BLA) is a natural compound that has been widely used for pain treatment but its role in osteolysis has not yet been investigated. In this study, we verified for the first time that BLA inhibited osteoclast formation, the mRNA expression of osteoclast-related genes and osteoclastic bone resorption by inhibiting NF-κB signal pathway and downstream NFATc1 expression. Meanwhile, BLA had a stimulatory effect in osteoblast differentiation and mineralization. Furthermore, BLA showed preventive effect in Ti particle-induced osteolysis model in vivo. Together, all our data demonstrated that BLA suppressed osteoclastogenesis and promoted osteoblastogenesis via suppressing NF-κB signal pathway and could be an alternative therapeutic choice against bone loss. © 2018 Wiley Periodicals, Inc.

  20. Quercetin suppresses insulin receptor signaling through inhibition of the insulin ligand–receptor binding and therefore impairs cancer cell proliferation

    International Nuclear Information System (INIS)

    Wang, Feng; Yang, Yong

    2014-01-01

    Graphical abstract: - Highlights: • Quercetin inhibits insulin ligand–receptor interactions. • Quercetin reduces downstream insulin receptor signaling. • Quercetin blocks insulin induced glucose uptake. • Quercetin suppresses insulin stimulated cancer cell proliferation and tumor growth. - Abstract: Although the flavonoid quercetin is known to inhibit activation of insulin receptor signaling, the inhibitory mechanism is largely unknown. In this study, we demonstrate that quercetin suppresses insulin induced dimerization of the insulin receptor (IR) through interfering with ligand–receptor interactions, which reduces the phosphorylation of IR and Akt. This inhibitory effect further inhibits insulin stimulated glucose uptake due to decreased cell membrane translocation of glucose transporter 4 (GLUT4), resulting in impaired cancer cell proliferation. The effect of quercetin in inhibiting tumor growth was also evident in an in vivo model, indicating a potential future application for quercetin in the treatment of cancers

  1. Antiplatelet action of indirubin-3'-monoxime through suppression of glycoprotein VI-mediated signal transduction: a possible role for ERK signaling in platelets.

    Science.gov (United States)

    Lee, Jung-Jin; Han, Joo-Hui; Jung, Sang-Hyuk; Lee, Sang-Gil; Kim, In-Su; Cuong, Nguyen Manh; Huong, Tran Thu; Khanh, Pham Ngoc; Kim, Young Ho; Yun, Yeo-Pyo; Ma, Jin Yeul; Myung, Chang-Seon

    2014-12-01

    We investigated the antiplatelet activity of indirubin-3'-monoxime (I3O) and the underlying mechanisms. In a rat carotid artery injury model, oral administration (20 mg/kg/day) of I3O for 3 days significantly prolonged occlusion time, and ADP- and collagen-induced platelet aggregation. In washed platelets in vitro, I3O potently inhibited collagen-induced platelet aggregation by suppressing phospholipase Cγ2 (PLCγ2) phosphorylation, subsequently blocking diacylglycerol and arachidonic acid (AA) formation, P-selectin secretion and the production of thromboxane B2. Platelet aggregation induced by phorbol-12-myristate 13-acetate, a protein kinase C (PKC) activator, was inhibited by I3O. Both I3O and U0126, an extracellular signal-regulated kinase 1/2 (ERK1/2) inhibitor, markedly reduced collagen-induced phosphorylation of ERK1/2 and p47, resulting in the blockade of cyclooxygenase (COX)-mediated AA metabolite production in AA-treated platelets. I3O suppressed phosphorylation of JNK, p38, GSK-3β, and AKT. I3O inhibited glycoprotein VI (GPVI), as a collagen receptor, by suppressing the phosphorylation of tyrosine kinase Syk of GPVI and the phosphorylation of PLCγ2 and ERK1/2 stimulated by convulxin, as a specific stimulator. Our results indicate that an antiplatelet effect of I3O is due to the suppression of GPVI-mediated signaling pathways. In collagen-stimulated platelets, ERK1/2 phosphorylation is adenylyl cyclase-dependent and leads to the modulation of PKC-p47 signaling and COX-1-mediated AA-metabolic pathways. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. ASH1L Suppresses Matrix Metalloproteinase through Mitogen-activated Protein Kinase Signaling Pathway in Pulpitis.

    Science.gov (United States)

    Bei, Yin; Tianqian, Hui; Fanyuan, Yu; Haiyun, Luo; Xueyang, Liao; Jing, Yang; Chenglin, Wang; Ling, Ye

    2017-02-01

    with in vitro results, ASH1L was found in increased quantities in experimental dental pulpitis tissue. ASH1L knockdown markedly up-regulated the occurrence of MMP-1, MMP-2, and MMP-13. It also exercised an impact on the enzymatic activity of MMP-2 in HDPCs that had been stimulated with TNF-α. ASH1L knockdown activated the MAPK signal pathway in TNF-α-triggered HDPCs, the inhibition of which reversed the induction of MMPs. Our research identifies a mechanism by which ASH1L suppresses the occurrence and operation of MMPs during pulpitis. It does this through the MAPK pathway. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  3. Mu suppression as an index of sensorimotor contributions to speech processing: evidence from continuous EEG signals.

    Science.gov (United States)

    Cuellar, Megan; Bowers, Andrew; Harkrider, Ashley W; Wilson, Matthew; Saltuklaroglu, Tim

    2012-08-01

    Mu rhythm suppression is an index of sensorimotor activity during the processing of sensory stimuli. Two present studies investigate the extent to which this measure is sensitive to differences in acoustic processing. In both studies, participants were required to listen to 90second acoustic stimuli clips with their eyes closed and identify predetermined targets. Experimental conditions were designed to vary the acoustic processing demands. Mu suppression was measured continuously across central electrodes (C3, Cz, and C4). Ten adult females participated in the first study in which the target was a pseudoword presented in three conditions (identification, discrimination, discrimination in noise). Mu suppression was strongest and reached significance relative to baseline only in the discrimination in noise task at C3 (indicative of left hemisphere sensorimotor activity) when measured in a 10-12Hz bandwidth. Thirteen adult females participated in the second study, which measured mu suppression to acoustic stimuli with 'segmentation' (i.e., separating a parsed stimulus into individual components) versus non-segmentation requirements in both speech and tone discrimination conditions. Significantly greater overall suppression to speech relative to tone tasks was found in the 10-12Hz bandwidth. Further, suppression relative to baseline was significant only at C3 during the speech discrimination with segmentation task. Taken together, findings indicate that mu rhythm suppression in acoustic processing is sensitive to dorsal stream processing. More specifically, it is sensitive to (1) increases in overall processing demands and (2) processing linguistic versus non-linguistic information. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. 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.

  5. A miniaturized compact open-loop RFOG with demodulation signal compensation technique to suppress intensity modulation noise

    Science.gov (United States)

    Ying, Diqing; Mao, Jianmin; Li, Qiang; Jin, Zhonghe

    2016-01-01

    A miniaturized compact open-loop resonator fiber optic gyro (RFOG) prototype with main body size of about 10.4 cm×10.4 cm×5.2 cm is reported, and a demodulation signal compensation technique is proposed, aiming to suppress the drift arising from accompanying intensity modulation induced by semiconductor laser diode (LD). The scheme of how to establish this miniaturized RFOG prototype is specifically stated. The linear relationship between the first-harmonic and second-harmonic demodulated signals respectively for the two counter propagating beams in the resonator is verified by theory and experiment, and based on this relationship, the demodulation signal compensation technique by monitoring the second-harmonic demodulated signal is described in detail. With this compensation technique, the gyro output stability under 1°/s rotation rate is effectively improved from 0.12°/s to 0.03°/s, and especially, an about 0.36°/s peak-to-peak fluctuation due to tuning current reset is significantly suppressed. A long term bias stability of about 4.5°/h in 1 h for such a small-sized RFOG prototype is demonstrated, which is of the same magnitude as that of currently reported large-sized RFOG systems utilizing LD as the laser source as well.

  6. Ganoderma lucidum (Reishi) suppresses proliferation and migration of breast cancer cells via inhibiting Wnt/β-catenin signaling.

    Science.gov (United States)

    Zhang, Yu

    2017-07-08

    The medical mushroom Ganoderma lucidum (Reishi), a traditional Chinese medicine, has exhibited a promising anti-cancer effect. However, the molecular mechanism of its action on cancer cells remains unclear. Aberrant activation of Wnt/β-catenin signaling pathway is the cause of many types of cancer, including breast cancer. Here we investigated the effect of Reishi on Wnt/β-catenin signaling pathway and elucidated the molecular mechanism of its function in inhibiting breast cancer cells. We found that Reishi blocked Wnt/β-catenin signaling through inhibiting the phosphorylation of Wnt co-receptor LRP6. In human (MDA-MB-231) and mouse (4T1) breast cancer cell lines, Reishi significantly decreased the phosphorylation of LRP6 and suppressed Wnt3a-activated Wnt target gene Axin2 expression. Administration of Reishi inhibited Wnt-induced hyper-proliferation of breast cancer cells and MDA-MB-231 cell migration. Our results provide evidence that Reishi suppresses breast cancer cell growth and migration through inhibiting Wnt/β-catenin signaling, indicating that Reishi may be a potential natural inhibitor for breast cancer. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Neural Substrates of Social Emotion Regulation: A fMRI Study on Imitation and Expressive Suppression to Dynamic Facial Signals

    Directory of Open Access Journals (Sweden)

    Pascal eVrticka

    2013-02-01

    Full Text Available Emotion regulation is crucial for successfully engaging in social interactions. Yet, little is known about the neural mechanisms controlling behavioral responses to emotional expressions perceived in the face of other people, which constitute a key element of interpersonal communication. Here, we investigated brain systems involved in social emotion perception and regulation, using functional magnetic resonance imaging (fMRI in 20 healthy participants who saw dynamic facial expressions of either happiness or sadness, and were asked to either imitate the expression or to suppress any expression on their own face (in addition to a gender judgment control task. fMRI results revealed higher activity in regions associated with emotion (e.g., the insula, motor function (e.g., motor cortex, and theory of mind during imitation. Activity in dorsal cingulate cortex was also increased during imitation, possibly reflecting greater action monitoring or conflict with own feeling states. In addition, premotor regions were more strongly activated during both imitation and suppression, suggesting a recruitment of motor control for both the production and inhibition of emotion expressions. Expressive suppression produced increases in dorsolateral and lateral prefrontal cortex typically related to cognitive control. These results suggest that voluntary imitation and expressive suppression modulate brain responses to emotional signals perceived from faces, by up- and down-regulating activity in distributed subcortical and cortical networks that are particularly involved in emotion, action monitoring, and cognitive control.

  8. Butyrate suppresses proliferation and migration of RKO colon cancer cells though regulating endocan expression by MAPK signaling pathway.

    Science.gov (United States)

    Zuo, Li; Lu, Man; Zhou, Qing; Wei, Wei; Wang, Yuan

    2013-12-01

    Butyrate is a short-chain fatty acid produced by colonic bacterial fermentation. In colon cancer cells butyrate is able to suppress cell growth, induce apoptosis. It also inhibits tumor growth in vivo. However, the underlying mechanism is still not fully understood. We hypothesize that butyrate regulates the growth and migration of colon cancer cells by altering endocan expression. To test this hypothesis, we performed quantitative real time RT–PCR and Western blots, and found that butyrate increased endocan expression of colon cancer cell RKO. Moreover, endocan over-expression inhibited RKO proliferation, migration and colony formation. Functionally, butyrate significantly suppressed RKO proliferation, migration, and colony formation, as well as induced apoptosis. Knocking down endogenous endocan was able to attenuate the inhibitory role of butyrate in RKO migration and proliferation. Since our results showed that butyrate inhibited MAPK/ERK2 phosphorylation. To determine whether ERK2 signaling is associated with endocan expression, we knocked down endogenous ERK2 expression. Our results showed that knocking down ERK2 expression up-regulated endocan expression. Taken together, these results suggested that butyrate suppressed RKO proliferation, colony formation, migration through up-regulating endocan expression via ERK2/MAPK signaling pathway.

  9. Simultaneous Suppression of IMD3 and IMD5 in Space TWT by IMD3 and 2HD Signal Injection

    Directory of Open Access Journals (Sweden)

    Dongming Zhao

    2017-01-01

    Full Text Available This paper presents a signal injection technology showing significant reductions in both 3rd-order and 5th-order intermodulation distortions (IMD3 and IMD5 in space traveling wave tube (STWT. By applying the IMD3 to the IMD5 ratio (TFR as measures of location, the simultaneous suppressions of IMD3 and IMD5 in TWT are achieved by second harmonic distortion (2HD and IMD3 injection. According to the research on theoretical analysis and computer simulation, the optimum amplitude and phase parameters of the injected signal for maximum simultaneous suppressions are obtained. Then an experiment system is established based on vector network analyzer, optimum TFR are 2.1 dB and 12.5 dB, respectively, by second harmonic and IM3 injection, and the output powers of IMD3 and IMD5 were decreased. TFR with IMD3 injection is smaller than that with second harmonic injection in STWT, and the experiment system is more straightforward and easy to operate. Thus, the IMD3 injection performs better than that of second harmonic injection to suppress IMD5s for the narrow-band STWT.

  10. Autophagy suppresses proliferation of HepG2 cells via inhibiting glypican-3/wnt/β-catenin signaling

    Directory of Open Access Journals (Sweden)

    Hu P

    2018-01-01

    Full Text Available Pei Hu,1,2 Bin Cheng,3 Yulin He,3 Zhiqiang Wei,3 Dongfang Wu,1 Zhongji Meng3,4 1Department of Pharmacy, Zhongnan Hospital of Wuhan University, Wuhan, 2Department of Clinical Laboratory Medicine, 3Institute of Biomedical Research, 4Department of Infectious Disease, Taihe Hospital, Hubei University of Medicine, Shiyan, People’s Republic of China Introduction: Autophagy plays an important role in the growth and survival of hepatocellular carcinoma (HCC cells through several target proteins or signaling pathways. Glypican-3 (GPC3 is a new reliable HCC marker, which is involved in tumor growth in HCC, primarily mediated by wnt/β-catenin signaling. Objective: The present study aimed to identify the role of autophagy in the proliferation of HepG2 cells through GPC3/wnt/β-catenin signaling. Results and discussion: Results demonstrated that induction of autophagy by nutrition starvation and rapamycin treatment led to the downregulation of GPC3 expression in HepG2 cells, accompanied by the decreased expression of wnt downstream target genes (β-catenin, c-myc and cyclin D1. On the other hand, inhibition of autophagy by 3-methyl adenine (3-MA could rescue rapamycin-directed downregulation of GPC3 and wnt/β-catenin target genes and augment the proliferation of HepG2 cells. Furthermore, interference of GPC3 by siRNA suppressed wnt/β-catenin signaling and attenuated 3-MA stimulation of HepG2 cell proliferation. More interestingly, the mRNA of GPC3 remained unchanged when the protein levels of GPC3 were decreased by autophagy activation, suggesting that induction of autophagy may accelerate the degradation of GPC3. Conclusion: These results suggest that autophagy suppresses proliferation of HepG2 cells partially by inhibition of GPC3/wnt/β-catenin signaling. Keywords: hepatocellular carcinoma, glypican-3, autophagy, proliferation, wnt/β-catenin signaling

  11. Notch signaling is significantly suppressed in basal cell carcinomas and activation induces basal cell carcinoma cell apoptosis.

    Science.gov (United States)

    Shi, Feng-Tao; Yu, Mei; Zloty, David; Bell, Robert H; Wang, Eddy; Akhoundsadegh, Noushin; Leung, Gigi; Haegert, Anne; Carr, Nicholas; Shapiro, Jerry; McElwee, Kevin J

    2017-04-01

    A subset of basal cell carcinomas (BCCs) are directly derived from hair follicles (HFs). In some respects, HFs can be defined as 'ordered' skin appendage growths, while BCCs can be regarded as 'disordered' skin appendage growths. The aim of the present study was to examine HFs and BCCs to define the expression of common and unique signaling pathways in each skin appendage. Human nodular BCCs, along with HFs and non‑follicular skin epithelium from normal individuals, were examined using microarrays, qPCR, and immunohistochemistry. Subsequently, BCC cells and root sheath keratinocyte cells from HFs were cultured and treated with Notch signaling peptide Jagged1 (JAG1). Gene expression, protein levels, and cell apoptosis susceptibility were assessed using qPCR, immunoblotting, and flow cytometry, respectively. Specific molecular mechanisms were found to be involved in the process of cell self‑renewal in the HFs and BCCs, including Notch and Hedgehog signaling pathways. However, several key Notch signaling factors showed significant differential expression in BCCs compared with HFs. Stimulating Notch signaling with JAG1 induced apoptosis of BCC cells by increasing Fas ligand expression and downstream caspase-8 activation. The present study showed that Notch signaling pathway activity is suppressed in BCCs, and is highly expressed in HFs. Elements of the Notch pathway could, therefore, represent targets for the treatment of BCCs and potentially in hair follicle engineering.

  12. Growth of Murine Splenic Tissue Is Suppressed by Lymphotoxin β-Receptor Signaling (LTβR) Originating from Splenic and Non-Splenic Tissues

    DEFF Research Database (Denmark)

    Milićević, Novica M; Nohroudi, Klaus; Schmidt, Friederike

    2016-01-01

    LTβR signaling. Two-dimensional differential gel electrophoresis and subsequent mass spectrometry of stromal splenic tissue was applied to screen for potential factors mediating the LTβR dependent suppressive activity. Thus, LTβR dependent growth suppression is involved in regulating the size...

  13. Hotair mediates hepatocarcinogenesis through suppressing miRNA-218 expression and activating P14 and P16 signaling.

    Science.gov (United States)

    Fu, Wei-Ming; Zhu, Xiao; Wang, Wei-Mao; Lu, Ying-Fei; Hu, Bao-Guang; Wang, Hua; Liang, Wei-Cheng; Wang, Shan-Shan; Ko, Chun-Hay; Waye, Mary Miu-Yee; Kung, Hsiang-Fu; Li, Gang; Zhang, Jin-Fang

    2015-10-01

    Long non-coding RNA Hotair has been considered as a pro-oncogene in multiple cancers. Although there is emerging evidence that reveals its biological function and the association with clinical prognosis, the precise mechanism remains largely elusive. We investigated the function and mechanism of Hotair in hepatocellular carcinoma (HCC) cell models and a xenograft mouse model. The regulatory network between miR-218 and Hotair was elucidated by RNA immunoprecipitation and luciferase reporter assays. Finally, the correlation between Hotair, miR-218 and the target gene Bmi-1 were evaluated in 52 paired HCC specimens. In this study, we reported that Hotair negatively regulated miR-218 expression in HCC, which might be mediated through an EZH2-targeting-miR-218-2 promoter regulatory axis. Further investigation revealed that Hotair knockdown dramatically inhibited cell viability and induced G1-phase arrest in vitro and suppressed tumorigenicity in vivo by promoting miR-218 expression. Oncogene Bmi-1 was shown to be a functional target of miR-218, and the main downstream targets signaling, P16(Ink4a) and P14(ARF), were activated in Hotair-suppressed tumorigenesis. In primary human HCC specimens, Hotair and Bmi-1 were concordantly upregulated whereas miR-218 was downregulated in these tissues. Furthermore, Hotair was inversely associated with miR-218 expression and positively correlated with Bmi-1 expression in these clinical tissues. Hotair silence activates P16(Ink4a) and P14(ARF) signaling by enhancing miR-218 expression and suppressing Bmi-1 expression, resulting in the suppression of tumorigenesis in HCC. Copyright © 2015 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

  14. Picrasidine I from Picrasma Quassioides Suppresses Osteoclastogenesis via Inhibition of RANKL Induced Signaling Pathways and Attenuation of ROS Production

    Directory of Open Access Journals (Sweden)

    Lingbo Kong

    2017-10-01

    Full Text Available Background/Aims: Osteoporosis is a metabolic bone disorder that tortures about millions of people worldwide. Recent study demonstrated agents derived from picrasma quassioides is a promising drug for targets multiple signaling pathways. However its potential in treatment of bone loss has not been fully understood. Methods: The bone marrow macrophages (BMMs were cultured and induced with M-CSF and RANKL followed by picrasidine I (PI treatment. Then the effects of PI on osteoclast formation were evaluated by counting tartrate-resistant acid phosphatase (TRAP-positive multinucleated cells. Moreover, effects of PI on bone resorption activity of mature osteoclast were studied through bone resorption pit counting and actin ring structure analysis. Further, the involved potential signaling pathways cross-talking were investigated by performed Western blotting and quantitative real-time PCR examination. Results: Results demonstrated PI strongly inhibited RANKL induced osteoclast formation from its precursors. Mechanistically, the inhibitory effect of PI on osteoclast differentiation was due to the suppression of osteoclastogenic transcription factors, c-Fos and NFATc1. Moreover, PI markedly blocked the RANKL-induced osteoclastogenesis by attenuating MAPKs and NF-κB signaling pathways. In addition, PI decreased the ROS generation in osteoclast and osteoblast. Conclusion: Taken together our data demonstrate that PI has antiosteoclastogenic effect by inhibiting inflammation induced activation of MAPKs, NF-κB and ROS generation followed by suppressing the gene expression of c-Fos and NFATc1 in osteoclast precursors.

  15. Picrasidine I from Picrasma Quassioides Suppresses Osteoclastogenesis via Inhibition of RANKL Induced Signaling Pathways and Attenuation of ROS Production.

    Science.gov (United States)

    Kong, Lingbo; Wang, Biao; Yang, Xiaobin; Guo, Hua; Zhang, Ke; Zhu, Ziqi; Liu, Jijun; Hao, Dingjun

    2017-01-01

    Osteoporosis is a metabolic bone disorder that tortures about millions of people worldwide. Recent study demonstrated agents derived from picrasma quassioides is a promising drug for targets multiple signaling pathways. However its potential in treatment of bone loss has not been fully understood. The bone marrow macrophages (BMMs) were cultured and induced with M-CSF and RANKL followed by picrasidine I (PI) treatment. Then the effects of PI on osteoclast formation were evaluated by counting tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells. Moreover, effects of PI on bone resorption activity of mature osteoclast were studied through bone resorption pit counting and actin ring structure analysis. Further, the involved potential signaling pathways cross-talking were investigated by performed Western blotting and quantitative real-time PCR examination. Results demonstrated PI strongly inhibited RANKL induced osteoclast formation from its precursors. Mechanistically, the inhibitory effect of PI on osteoclast differentiation was due to the suppression of osteoclastogenic transcription factors, c-Fos and NFATc1. Moreover, PI markedly blocked the RANKL-induced osteoclastogenesis by attenuating MAPKs and NF-κB signaling pathways. In addition, PI decreased the ROS generation in osteoclast and osteoblast. Taken together our data demonstrate that PI has antiosteoclastogenic effect by inhibiting inflammation induced activation of MAPKs, NF-κB and ROS generation followed by suppressing the gene expression of c-Fos and NFATc1 in osteoclast precursors. © 2017 The Author(s). Published by S. Karger AG, Basel.

  16. Fasting induced kisspeptin signaling suppression is regulated by glutamate mediated cues in adult male rhesus macaque (Macaca mulatta).

    Science.gov (United States)

    Shamas, Shazia; Khan, Saeed-Ul-Hassan; Khan, Muhammad Yousaf; Shabbir, Nadia; Zubair, Hira; Shafqat, Saira; Wahab, Fazal; Shahab, Muhammad

    2015-08-01

    Kisspeptin signaling is suppressed by short term fasting. It has been reported that hypothalamic Kiss1 and Kiss1r mRNA expression decreased after 48h of fasting in male rhesus monkey. But the mechanism involved in the reduction of kisspeptin signaling after 48h of fasting is unknown. Recent studies have suggested the role of afferent excitatory and inhibitory pathways in the regulation of kisspeptin neurons. Therefore, this study was designed to observe the changes in the glutamate and GABA signaling during fed and 48h fasting states by performing immunofluorescence to examine the interaction of kisspeptin neurons with NR1 subunit of NMDA receptors and by performing SYBR green qRT-PCR to measure and quantify the levels of Kiss1, Kiss1r, NR1 and GAD67 mRNA in the POA and MBH of adult male rhesus macaque (Macaca mulatta) during 48h of fasting (n=2) and fed ad libitum (n=2). Plasma testosterone (pfasting. Our results clearly showed that expression of hypothalamic Kiss1, Kiss1r and NR1 mRNA was significantly (pfasted for 48h as compared to those which were fed ad libitum. There was no clear difference in the GAD67 mRNA contents between the two groups. Number of kisspeptin neurons and the interactions of kisspeptin neurons with NR1 were significantly (pfasting. These observations suggest that decreased kisspeptin signaling during fasting may occur due to reduction in glutamatergic inputs to kisspeptin neurons. Our results also suggest that fasting induced suppression of kisspeptin signaling is not mediated through GABAergic neurons. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Glucocorticoids Suppress the Protective Effect of Cyclooxygenase-2-Related Signaling on Hippocampal Neurogenesis Under Acute Immune Stress.

    Science.gov (United States)

    Ma, Yanbo; Matsuwaki, Takashi; Yamanouchi, Keitaro; Nishihara, Masugi

    2017-04-01

    Stress and glucocorticoids suppress adult neurogenesis in the hippocampus. However, the molecular mechanisms underlying stress-induced impairment of adult neurogenesis are poorly understood. We previously suggested that cyclooxygenase (COX)-2 is a common mediator of stresses in the brain. Here, using a lipopolysaccharide (LPS)-induced acute infectious stress model, we evaluated the roles of COX-2 and its major downstream product prostaglandin E2 (PGE2) in adult neurogenesis and the influence of glucocorticoids on COX-2-related signaling. Treatment of rats with LPS significantly decreased neurogenesis in the dentate gyrus (DG) of the hippocampus, and this inhibitory effect of LPS on neurogenesis was reversed by the glucocorticoid receptor antagonist RU486. Moreover, RU486 significantly enhanced the increase in messenger RNA (mRNA) levels of COX-2 and microsomal prostaglandin E synthase (mPGES)-1 in the hippocampus following LPS stimulation. Administration of AH6809, a selective antagonist of the PGE2 EP2 receptor, as well as NS398, a COX-2 selective inhibitor, exacerbated the suppression of proliferation of neural progenitor cells (NPCs) in the DG. Gene expression of EP1, EP2, and EP3, but not EP4, receptors was also increased following LPS stimulation. Immunohistochemical studies indicated that NPCs expressed EP2 receptor, whereas the majority of cells expressing COX-2 and mPGES-1 were mature neurons in the DG. These results suggest that acute infectious stress upregulates COX-2-related signaling in neurons in the DG, which plays a protective role in neurogenesis through EP2 receptor at least partially. In addition, LPS-induced glucocorticoids suppress this COX-2-related signaling, resulting in decreased neurogenesis.

  18. Stem signal suppression in fiber-coupled Al2O3:C dosimetry for 192Ir brachytherapy

    DEFF Research Database (Denmark)

    Kertzscher Schwencke, Gustavo Adolfo Vladimir; Andersen, Claus Erik; Edmund, J.M.

    2011-01-01

    was adapted for on-line in-vivo dosimetry using fiber-coupled carbon doped aluminum oxide (Al2O3:C). The technique involved a two-channel optical filtration of the radioluminescence (RL) emitted from a pre-irradiated Al2O3:C crystal with enhanced sensitivity. The system responded linearly in the absorbed dose......The stem signal, composed of fluorescence and Čerenkov light, becomes a significant source of uncertainty in fiber-coupled afterloaded brachytherapy dosimetry when the source dwells near the fiber cable but far from the detector. A stem suppression technique originally developed for scintillators...

  19. Tribbles 3 inhibits brown adipocyte differentiation and function by suppressing insulin signaling

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Ha-Won; Choi, Ran Hee; McClellan, Jamie L. [Division of Applied Physiology, Department of Exercise Science, University of South Carolina, Columbia, SC 29208 (United States); Piroli, Gerardo G.; Frizzell, Norma [Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC 29208 (United States); Tseng, Yu-Hua; Goodyear, Laurie J. [Research Division, Joslin Diabetes Center and Department of Medicine, Harvard Medical School, Boston, MA 02215 (United States); Koh, Ho-Jin, E-mail: kohh@mailbox.sc.edu [Division of Applied Physiology, Department of Exercise Science, University of South Carolina, Columbia, SC 29208 (United States)

    2016-02-19

    Recent studies have demonstrated that adult humans have substantial amounts of functioning brown adipose tissue (BAT). Since BAT has been implicated as an anti-obese and anti-diabetic tissue, it is important to understand the signaling molecules that regulate BAT function. There has been a link between insulin signaling and BAT metabolism as deletion or pharmaceutical inhibition of insulin signaling impairs BAT differentiation and function. Tribbles 3 (TRB3) is a pseudo kinase that has been shown to regulate metabolism and insulin signaling in multiple tissues but the role of TRB3 in BAT has not been studied. In this study, we found that TRB3 expression was present in BAT and overexpression of TRB3 in brown preadipocytes impaired differentiation and decreased expression of BAT markers. Furthermore, TRB3 overexpression resulted in significantly lower oxygen consumption rates for basal and proton leakage, indicating decreased BAT activity. Based on previous studies showing that deletion or pharmaceutical inhibition of insulin signaling impairs BAT differentiation and function, we assessed insulin signaling in brown preadipocytes and BAT in vivo. Overexpression of TRB3 in cells impaired insulin-stimulated IRS1 and Akt phosphorylation, whereas TRB3KO mice displayed improved IRS1 and Akt phosphorylation. Finally, deletion of IRS1 abolished the function of TRB3 to regulate BAT differentiation and metabolism. These data demonstrate that TRB3 inhibits insulin signaling in BAT, resulting in impaired differentiation and function. - Highlights: • TRB3 is expressed in brown adipose tissue and its expression is increased during differentiation. • Overexpression of TRB3 inhibits differentiation and its activity. • Overexpression of TRB3 in brown preadipocytes inhibits insulin signaling. • TRB3KO mice displays improved insulin signaling in brown adipose tissue. • Insulin signaling is required for the effects of TRB3 to regulate brown adipose tissue differentiation and

  20. A Digital Signal Processing Method for Gene Prediction with Improved Noise Suppression

    Directory of Open Access Journals (Sweden)

    Carreira Alex

    2004-01-01

    Full Text Available It has been observed that the protein-coding regions of DNA sequences exhibit period-three behaviour, which can be exploited to predict the location of coding regions within genes. Previously, discrete Fourier transform (DFT and digital filter-based methods have been used for the identification of coding regions. However, these methods do not significantly suppress the noncoding regions in the DNA spectrum at . Consequently, a noncoding region may inadvertently be identified as a coding region. This paper introduces a new technique (a single digital filter operation followed by a quadratic window operation that suppresses nearly all of the noncoding regions. The proposed method therefore improves the likelihood of correctly identifying coding regions in such genes.

  1. Branched-chain amino acids in metabolic signalling and insulin resistance.

    Science.gov (United States)

    Lynch, Christopher J; Adams, Sean H

    2014-12-01

    Branched-chain amino acids (BCAAs) are important nutrient signals that have direct and indirect effects. Frequently, BCAAs have been reported to mediate antiobesity effects, especially in rodent models. However, circulating levels of BCAAs tend to be increased in individuals with obesity and are associated with worse metabolic health and future insulin resistance or type 2 diabetes mellitus (T2DM). A hypothesized mechanism linking increased levels of BCAAs and T2DM involves leucine-mediated activation of the mammalian target of rapamycin complex 1 (mTORC1), which results in uncoupling of insulin signalling at an early stage. A BCAA dysmetabolism model proposes that the accumulation of mitotoxic metabolites (and not BCAAs per se) promotes β-cell mitochondrial dysfunction, stress signalling and apoptosis associated with T2DM. Alternatively, insulin resistance might promote aminoacidaemia by increasing the protein degradation that insulin normally suppresses, and/or by eliciting an impairment of efficient BCAA oxidative metabolism in some tissues. Whether and how impaired BCAA metabolism might occur in obesity is discussed in this Review. Research on the role of individual and model-dependent differences in BCAA metabolism is needed, as several genes (BCKDHA, PPM1K, IVD and KLF15) have been designated as candidate genes for obesity and/or T2DM in humans, and distinct phenotypes of tissue-specific branched chain ketoacid dehydrogenase complex activity have been detected in animal models of obesity and T2DM.

  2. New Insights Into the Role of mTOR Signaling in the Cardiovascular System.

    Science.gov (United States)

    Sciarretta, Sebastiano; Forte, Maurizio; Frati, Giacomo; Sadoshima, Junichi

    2018-02-02

    The mTOR (mechanistic target of rapamycin) is a master regulator of several crucial cellular processes, including protein synthesis, cellular growth, proliferation, autophagy, lysosomal function, and cell metabolism. mTOR interacts with specific adaptor proteins to form 2 multiprotein complexes, called mTORC1 (mTOR complex 1) and mTORC2 (mTOR complex 2). In the cardiovascular system, the mTOR pathway regulates both physiological and pathological processes in the heart. It is needed for embryonic cardiovascular development and for maintaining cardiac homeostasis in postnatal life. Studies involving mTOR loss-of-function models revealed that mTORC1 activation is indispensable for the development of adaptive cardiac hypertrophy in response to mechanical overload. mTORC2 is also required for normal cardiac physiology and ensures cardiomyocyte survival in response to pressure overload. However, partial genetic or pharmacological inhibition of mTORC1 reduces cardiac remodeling and heart failure in response to pressure overload and chronic myocardial infarction. In addition, mTORC1 blockade reduces cardiac derangements induced by genetic and metabolic disorders and has been reported to extend life span in mice. These studies suggest that pharmacological targeting of mTOR may represent a therapeutic strategy to confer cardioprotection, although clinical evidence in support of this notion is still scarce. This review summarizes and discusses the new evidence on the pathophysiological role of mTOR signaling in the cardiovascular system. © 2018 American Heart Association, Inc.

  3. A simple predistortion technique for suppression of nonlinear effects in periodic signals generated by nonlinear transducers

    Science.gov (United States)

    Novak, A.; Simon, L.; Lotton, P.

    2018-04-01

    Mechanical transducers, such as shakers, loudspeakers and compression drivers that are used as excitation devices to excite acoustical or mechanical nonlinear systems under test are imperfect. Due to their nonlinear behaviour, unwanted contributions appear at their output besides the wanted part of the signal. Since these devices are used to study nonlinear systems, it should be required to measure properly the systems under test by overcoming the influence of the nonlinear excitation device. In this paper, a simple method that corrects distorted output signal of the excitation device by means of predistortion of its input signal is presented. A periodic signal is applied to the input of the excitation device and, from analysing the output signal of the device, the input signal is modified in such a way that the undesirable spectral components in the output of the excitation device are cancelled out after few iterations of real-time processing. The experimental results provided on an electrodynamic shaker show that the spectral purity of the generated acceleration output approaches 100 dB after few iterations (1 s). This output signal, applied to the system under test, is thus cleaned from the undesirable components produced by the excitation device; this is an important condition to ensure a correct measurement of the nonlinear system under test.

  4. Recent Progress on Liver Kinase B1 (LKB1: Expression, Regulation, Downstream Signaling and Cancer Suppressive Function

    Directory of Open Access Journals (Sweden)

    Ren-You Gan

    2014-09-01

    Full Text Available Liver kinase B1 (LKB1, known as a serine/threonine kinase, has been identified as a critical cancer suppressor in many cancer cells. It is a master upstream kinase of 13 AMP-activated protein kinase (AMPK-related protein kinases, and possesses versatile biological functions. LKB1 gene is mutated in many cancers, and its protein can form different protein complexes with different cellular localizations in various cell types. The expression of LKB1 can be regulated through epigenetic modification, transcriptional regulation and post-translational modification. LKB1 dowcnstream pathways mainly include AMPK, microtubule affinity regulating kinase (MARK, salt-inducible kinase (SIK, sucrose non-fermenting protein-related kinase (SNRK and brain selective kinase (BRSK signalings, etc. This review, therefore, mainly discusses recent studies about the expression, regulation, downstream signaling and cancer suppressive function of LKB1, which can be helpful for better understanding of this molecular and its significance in cancers.

  5. TGF-β1/Smad2/3/Foxp3 signaling is required for chronic stress-induced immune suppression.

    Science.gov (United States)

    Zhang, Haiju; Caudle, Yi; Wheeler, Clay; Zhou, Yu; Stuart, Charles; Yao, Baozhen; Yin, Deling

    2018-01-15

    Depending on the duration and severity, psychological tension and physical stress can enhance or suppress the immune system in both humans and animals. Although it has been established that chronic stress exerts a significant suppressive effect on immune function, the mechanisms by which affects immune responses remain elusive. By employing an in vivo murine system, we revealed that TGF-β1/Smad2/3/Foxp3 axis was remarkably activated following chronic stress. Furthermore, TLR9 and p38 MAPK played a critical role in the activation of TGF-β1/Smad2/3/Foxp3 signaling cascade. Moreover, inhibition of TGF-β1/Smad2/3/Foxp3 or p38 significantly attenuated chronic stress-induced lymphocyte apoptosis and apoptosis-related proteins, as well as the differentiation of T regulatory cells in spleen. Interestingly, disequilibrium of pro-inflammatory and anti-inflammatory cytokines balance caused by chronic stress was also rescued by blocking TGF-β1/Smad2/3/Foxp3 axis. These findings yield insight into a novel mechanism by which chronic stress modulates immune functions and identifies new targets for the development of novel anti-immune suppressant medications. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. High signal in bone marrow at diffusion-weighted imaging with body background suppression (DWIBS) in healthy children

    Energy Technology Data Exchange (ETDEWEB)

    Ording Mueller, Lil-Sofie; Avenarius, Derk [University Hospital North Norway, Department of Radiology, Tromsoe (Norway); Olsen, Oeystein E. [Great Ormond Street Hospital for Children, Department of Radiology, London (United Kingdom)

    2011-02-15

    In our experience, diffusion-weighted imaging with body background suppression (DWIBS) is hard to interpret in children who commonly have foci of restricted diffusion in their skeletons unrelated to pathology, sometimes in an asymmetrical pattern. This raises serious concern about the accuracy of DWIBS in cancer staging in children. To describe the signal distribution at DWIBS in the normal developing lumbar spine and pelvic skeleton. Forty-two healthy children underwent an MR DWIBS sequence of the abdomen and pelvis. An axial short-tau inversion-recovery (STIR) echo-planar imaging (EPI) pulse sequence was used. Two radiologists did a primary review of the images and based on these preliminary observations, separate scoring systems for the lumbar spine, pelvis and proximal femoral epiphyses/femoral heads were devised. Visual evaluation of the images was then performed by the two radiologists in consensus. The scoring was repeated separately 2 months later by a third radiologist. Restricted diffusion was defined as areas of high signal compared to the background. Coronal maximum intensity projection (MIP) reformats were used to assess the vertebral bodies. For the pelvis, the extension of high signal for each bone was given a score of 0 to 4. Cohen's Kappa interobserver agreement coefficients of signal distribution and asymmetry were calculated. All children had areas of high signal, both within the lumbar vertebral bodies and within the pelvic skeleton. Three patterns of signal distribution were seen in the lumbar spine, but no specific pattern was seen in the pelvis. There was a tendency toward a reduction of relative area of high signal within each bone with age, but also a widespread interindividual variation. Restricted diffusion is a normal finding in the pelvic skeleton and lumbar spine in children with an asymmetrical distribution seen in 48% of normal children in this study. DWIBS should be used with caution for cancer staging in children as this could

  7. Suppressing thyroid hormone signaling preserves cone photoreceptors in mouse models of retinal degeneration

    OpenAIRE

    Ma, Hongwei; Thapa, Arjun; Morris, Lynsie; Redmond, T. Michael; Baehr, Wolfgang; Ding, Xi-Qin

    2014-01-01

    Photoreceptors degenerate in a wide array of hereditary retinal diseases and age-related macular degeneration. There is currently no treatment available for retinal degenerations. While outnumbered roughly 20:1 by rods in the human retina, it is the cones that mediate color vision and visual acuity, and their survival is critical for vision. In this communication, we investigate whether thyroid hormone (TH) signaling affects cone viability in retinal degeneration mouse models. TH signaling is...

  8. G-Protein Gαs controls medulloblastoma initiation by suppressing sonic hedgehog signaling.

    Science.gov (United States)

    He, Xuelian; Lu, Q Richard

    2015-01-01

    We identify Gαs as a novel tumor suppressor in medulloblastoma that functions principally by inhibition of sonic hedgehog signaling. Gαs not only stimulates cyclic adenosine monophosphate (cAMP)-dependent signaling but also inhibits ciliary trafficking of hedgehog components. Elevation of cAMP inhibits medulloblastoma growth and augments inhibition of smoothened to decrease tumor cell proliferation, thus highlighting Gαs as a potential therapeutic target.

  9. Ganoderma lucidum suppresses growth of breast cancer cells through the inhibition of Akt/NF-kappaB signaling.

    Science.gov (United States)

    Jiang, Jiahua; Slivova, Veronika; Harvey, Kevin; Valachovicova, Tatiana; Sliva, Daniel

    2004-01-01

    Ganoderma lucidum (Reishi, Lingzhi) is a popular Asian mushroom that has been used for more than 2 millennia for the general promotion of health and was therefore called the "Mushroom of Immortality." Ganoderma lucidum was also used in traditional Chinese medicine to prevent or treat a variety of diseases, including cancer. We previously demonstrated that Ganoderma lucidum suppresses the invasive behavior of breast cancer cells by inhibiting the transcription factor NF-kappaB. However, the molecular mechanisms responsible for the inhibitory effects of Ganoderma lucidum on the growth of highly invasive and metastatic breast cancer cells has not been fully elucidated. Here, we show that Ganoderma lucidum inhibits proliferation of breast cancer MDA-MB-231 cells by downregulating Akt/NF-kappaB signaling. Ganoderma lucidum suppresses phosphorylation of Akt on Ser473 and downregulates the expression of Akt, which results in the inhibition of NF-kappaB activity in MDA-MB-231 cells. The biological effect of Ganoderma lucidum was demonstrated by cell cycle arrest at G0/G1, which was the result of the downregulation of expression of NF-kappaB-regulated cyclin D1, followed by the inhibition of cdk4. Our results suggest that Ganoderma lucidum inhibits the growth of MDA-MB-231 breast cancer cells by modulating Akt/NF-kappaB signaling and could have potential therapeutic use for the treatment of breast cancer.

  10. Bixa orellana leaf extract suppresses histamine-induced endothelial hyperpermeability via the PLC-NO-cGMP signaling cascade.

    Science.gov (United States)

    Yong, Yoke Keong; Chiong, Hoe Siong; Somchit, Muhd Nazrul; Ahmad, Zuraini

    2015-10-14

    Histamine is established as a potent inflammatory mediator and it is known to increased endothelial permeability by promoting gap formation between endothelial cells. Previous studies have shown that aqueous extract of Bixa orellana leaves (AEBO) exhibits antihistamine activity in vivo, yet the mechanism of its action on endothelial barrier function remains unclear. Therefore, the current study aimed to determine the protective effect of AEBO against histamine-induced hyperpermeability in vitro. The endothelial protective effect of AEBO was assess using an in vitro vascular permeability assay kit. Human umbilical vein endothelial cells (HUVEC) were used in the current study. HUVEC were pre-treated with AEBO for 12 h before histamine induction. Vascular permeability was evaluated by the amount of FITC-dextran leakage into the lower chamber. In order to elucidate the mechanism of action of AEBO, phospholipase C (PLC) activity, intracellular calcium level, nitric oxide (NO) concentration, cyclic guanosine monophosphate (cGMP) production and protein kinase C (PKC) activity were determined following histamine challenge. Histamine-induced increased HUVEC permeability was significantly attenuated by pretreatment with AEBO in a time- and concentration-dependent manner. Upregulation of PLC activity caused by histamine in HUVEC was suppressed by pretreatment with AEBO. Pretreatment with AEBO also blocked the production of intracellular calcium induced by histamine in HUVEC. In addition, AEBO suppressed the NO-cGMP signaling cascade when HUVEC were challenged with histamine. Moreover, PKC activity was significantly abolished by pretreatment with AEBO in HUVEC under histamine condition. In conclusion, the present data suggest that AEBO could suppress histamine-induced increased endothelial permeability and the activity may be closely related with the inhibition of the PLC-NO-cGMP signaling pathway and PKC activity.

  11. RYBP Inhibits Progression and Metastasis of Lung Cancer by Suppressing EGFR Signaling and Epithelial-Mesenchymal Transition

    Directory of Open Access Journals (Sweden)

    Xiaoxiao Dinglin

    2017-04-01

    Full Text Available Lung cancer (LC is a common lethal malignancy with rapid progression and metastasis, and Ring1 and YY1 binding protein (RYBP has been shown to suppress cell growth in human cancers. This study aimed to investigate the role of RYBP in LC progression and metastasis. In this study, a total of 149 LC patients were recruited, and the clinical stage of their tumors, metastasis status, survival time, presence of epidermal growth factor receptor (EGFR mutation, and RYBP expression levels were measured. RYBP silencing and overexpression were experimentally performed in LC cell lines and in nude mice, and the expressions of genes in EGFR-related signaling pathways and epithelial-mesenchymal transition (EMT were detected. The results showed that RYBP was downregulated in LC compared with adjacent normal tissues, and low RYBP expression was associated with a more severe clinical stage, high mortality, high metastasis risk, and poor survival. Cell proliferation and xenograft growth were inhibited by RYBP overexpression, whereas proliferation and xenograft growth were accelerated by RYBP silencing. EGFR and phosphorylated-EGFR levels were upregulated when RYBP was silenced, whereas EGFR, p-EGFR, p-AKT, and p-ERK were downregulated when RYBP was overexpressed. Low RYBP expression was related to a high metastasis risk, and metastasized tumors showed low RYBP levels. Cell migration and invasion were promoted by silencing RYBP but were inhibited by overexpressed RYBP. In addition, the EMT marker vimentin showed diminished expression, and E-cadherin was promoted by the overexpression of RYBP. In conclusion, our data suggest that RYBP suppresses cell proliferation and LC progression by impeding the EGFR-ERK and EGFR-AKT signaling pathways and thereby inhibiting cell migration and invasion and LC metastasis through the suppression of EMT.

  12. Triptolide inhibits TGF-β1-induced cell proliferation in rat airway smooth muscle cells by suppressing Smad signaling

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ming; Lv, Zhiqiang; Huang, Linjie [Department of Respiratory Medicine, Sun Yat-Sen Memorial Hospital, Institute for Respiratory disease of Sun Yat-sen University, Sun Yat-sen University, Guangzhou, Guangdong Province 510120 (China); Zhang, Wei [Department of Geratology, the Second People' s Hospital of Shenzhen, Shenzhen 518000 (China); Lin, Xiaoling; Shi, Jianting; Zhang, Wei; Liang, Ruiyun [Department of Respiratory Medicine, Sun Yat-Sen Memorial Hospital, Institute for Respiratory disease of Sun Yat-sen University, Sun Yat-sen University, Guangzhou, Guangdong Province 510120 (China); Jiang, Shanping, E-mail: shanpingjiang@126.com [Department of Respiratory Medicine, Sun Yat-Sen Memorial Hospital, Institute for Respiratory disease of Sun Yat-sen University, Sun Yat-sen University, Guangzhou, Guangdong Province 510120 (China)

    2015-02-15

    Background: We have reported that triptolide can inhibit airway remodeling in a murine model of asthma via TGF-β1/Smad signaling. In the present study, we aimed to investigate the effect of triptolide on airway smooth muscle cells (ASMCs) proliferation and the possible mechanism. Methods: Rat airway smooth muscle cells were cultured and made synchronized, then pretreated with different concentration of triptolide before stimulated by TGF-β1. Cell proliferation was evaluated by MTT assay. Flow cytometry was used to study the influence of triptolide on cell cycle and apoptosis. Signal proteins (Smad2, Smad3 and Smad7) were detected by western blotting analysis. Results: Triptolide significantly inhibited TGF-β1-induced ASMC proliferation (P<0.05). The cell cycle was blocked at G1/S-interphase by triptolide dose dependently. No pro-apoptotic effects were detected under the concentration of triptolide we used. Western blotting analysis showed TGF-β1 induced Smad2 and Smad3 phosphorylation was inhibited by triptolide pretreatment, and the level of Smad7 was increased by triptolide pretreatment. Conclusions: Triptolide may function as an inhibitor of asthma airway remodeling by suppressing ASMCs proliferation via negative regulation of Smad signaling pathway. - Highlights: • In this study, rat airway smooth muscle cells were cultured and made synchronized. • Triptolide inhibited TGF-β1-induced airway smooth muscle cells proliferation. • Triptolide inhibited ASMCs proliferation via negative regulation of Smad signaling pathway.

  13. Insulin-like growth factor-1 suppresses the Myostatin signaling pathway during myogenic differentiation

    Energy Technology Data Exchange (ETDEWEB)

    Retamales, A.; Zuloaga, R.; Valenzuela, C.A. [Laboratorio de Biotecnología Molecular, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Santiago (Chile); Gallardo-Escarate, C. [Laboratory of Biotechnology and Aquatic Genomics, Universidad de Concepción, Concepción (Chile); Interdisciplinary Center for Aquaculture Research (INCAR), P.O. Box 160-C, Concepción (Chile); Molina, A. [Laboratorio de Biotecnología Molecular, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Santiago (Chile); Interdisciplinary Center for Aquaculture Research (INCAR), P.O. Box 160-C, Concepción (Chile); Valdés, J.A., E-mail: jvaldes@unab.cl [Laboratorio de Biotecnología Molecular, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Santiago (Chile); Interdisciplinary Center for Aquaculture Research (INCAR), P.O. Box 160-C, Concepción (Chile)

    2015-08-21

    Myogenic differentiation is a complex and well-coordinated process for generating mature skeletal muscle fibers. This event is autocrine/paracrine regulated by growth factors, principally Myostatin (MSTN) and Insulin-like Growth Factor-1 (IGF-1). Myostatin, a member of the transforming growth factor-β superfamily, is a negative regulator of skeletal muscle growth in vertebrates that exerts its inhibitory function by activating Smad transcription factors. In contrast, IGF-1 promotes the differentiation of skeletal myoblasts by activating the PI3K/Akt signaling pathway. This study reports on a novel functional crosstalk between the IGF-1 and MSTN signaling pathways, as mediated through interaction between PI3K/Akt and Smad3. Stimulation of skeletal myoblasts with MSTN resulted in a transient increase in the pSmad3:Smad3 ratio and Smad-dependent transcription. Moreover, MSTN inhibited myod gene expression and myoblast fusion in an Activin receptor-like kinase/Smad3-dependent manner. Preincubation of skeletal myoblasts with IGF-1 blocked MSTN-induced Smad3 activation, promoting myod expression and myoblast differentiation. This inhibitory effect of IGF-1 on the MSTN signaling pathway was dependent on IGF-1 receptor, PI3K, and Akt activities. Finally, immunoprecipitation assay analysis determined that IGF-1 pretreatment increased Akt and Smad3 interaction. These results demonstrate that the IGF-1/PI3K/Akt pathway may inhibit MSTN signaling during myoblast differentiation, providing new insight to existing knowledge on the complex crosstalk between both growth factors. - Highlights: • IGF-1 inhibits Myostatin canonical signaling pathway through IGF-1R/PI3K/Akt pathway. • IGF-1 promotes myoblast differentiation through a direct blocking of Myostatin signaling pathway. • IGF-1 induces the interaction of Akt with Smad3 in skeletal myoblast.

  14. Activated protein synthesis and suppressed protein breakdown signaling in skeletal muscle of critically ill patients

    DEFF Research Database (Denmark)

    Jespersen, Jakob G; Nedergaard, Anders; Reitelseder, Søren

    2011-01-01

    involved in muscle mass regulation, we investigated the phosphorylation and expression of key factors in these protein synthesis and breakdown signaling pathways in thigh skeletal muscle of critically ill intensive care unit (ICU) patients compared with healthy controls.......Skeletal muscle mass is controlled by myostatin and Akt-dependent signaling on mammalian target of rapamycin (mTOR), glycogen synthase kinase 3ß (GSK3ß) and forkhead box O (FoxO) pathways, but it is unknown how these pathways are regulated in critically ill human muscle. To describe factors...

  15. The aryl hydrocarbon receptor suppresses osteoblast proliferation and differentiation through the activation of the ERK signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Haitao; Du, Yuxuan; Zhang, Xulong; Sun, Ying; Li, Shentao; Dou, Yunpeng [Department of Immunology, School of Basic Medical Sciences, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069 (China); Li, Zhanguo [Department of Rheumatology and Immunology, Clinical Immunology Center, Peking University People' s Hospital, No. 11 Xizhimen South Street, Beijing 100044 (China); Yuan, Huihui, E-mail: huihui_yuan@163.com [Department of Immunology, School of Basic Medical Sciences, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069 (China); Zhao, Wenming, E-mail: zhao-wenming@163.com [Department of Immunology, School of Basic Medical Sciences, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069 (China)

    2014-11-01

    Ahr activation is known to be associated with synovitis and exacerbated rheumatoid arthritis (RA), but its contributions to bone loss have not been completely elucidated. Osteoblast proliferation and differentiation are abnormal at the erosion site in RA. Here, we reported that the expression of Ahr was increased in the hind paws' bone upon collagen-induced arthritis (CIA) in mice, and the levels of Ahr were negatively correlated with bone mineral density (BMD). In addition, immunofluorescent staining showed that the high expression of Ahr was mainly localized in osteoblasts from the CIA mice compared to normal controls. Moreover, the luciferase intensity of Ahr in the nucleus increased by 12.5% in CIA osteoblasts compared to that in normal controls. In addition, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) activation of the Ahr inhibited pre-osteoblast MC3T3-E1 cellular proliferation and differentiation in a dose-dependent manner. Interestingly, the levels of alkaline phosphatase (ALP) mRNA expression in the osteoblasts of CIA mice were reduced compared to normal controls. In contrast, decreased ALP expression by activated Ahr was completely reversed after pretreatment with an Ahr inhibitor (CH-223191) in MC3T3-E1 cell lines and primary osteoblasts on day 5. Our data further showed that activation of Ahr promoted the phosphorylation of ERK after 5 days. Moreover, Ahr-dependent activation of the ERK signaling pathway decreased the levels of proliferation cells and inhibited ALP activity in MC3T3-E1 cells. These results demonstrated that the high expression of Ahr may suppress osteoblast proliferation and differentiation through activation of the ERK signaling pathway, further enabling bone erosion in CIA mice. - Highlights: • The upregulation of Ahr was localized in osteoblasts of CIA mice. • The overexpression of Ahr suppressed osteoblast development. • The Ahr activated ERK signaling pathway to exacerbate bone erosion.

  16. Activated protein synthesis and suppressed protein breakdown signaling in skeletal muscle of critically ill patients

    DEFF Research Database (Denmark)

    Jespersen, Jakob G; Nedergaard, Anders; Reitelseder, Søren

    2011-01-01

    Skeletal muscle mass is controlled by myostatin and Akt-dependent signaling on mammalian target of rapamycin (mTOR), glycogen synthase kinase 3ß (GSK3ß) and forkhead box O (FoxO) pathways, but it is unknown how these pathways are regulated in critically ill human muscle. To describe factors...

  17. Activated protein synthesis and suppressed protein breakdown signaling in skeletal muscle of critically ill patients

    DEFF Research Database (Denmark)

    Jespersen, Jakob G; Nedergaard, Anders; Reitelseder, Søren

    2011-01-01

    Skeletal muscle mass is controlled by myostatin and Akt-dependent signaling on mammalian target of rapamycin (mTOR), glycogen synthase kinase 3β (GSK3β) and forkhead box O (FoxO) pathways, but it is unknown how these pathways are regulated in critically ill human muscle. To describe factors...

  18. Erk signaling suppresses embryonic stem cell self-renewal to specify endoderm

    DEFF Research Database (Denmark)

    Hamilton, William B; Brickman, Joshua M

    2014-01-01

    Fgf signaling via Erk activation has been associated with both neural induction and the generation of a primed state for the differentiation of embryonic stem cells (ESCs) to all somatic lineages. To dissect the role of Erk in both ESC self-renewal and lineage specification, we explored...

  19. Tick saliva suppresses IFN signalling in dendritic cells upon Borrelia afzelii infection

    Czech Academy of Sciences Publication Activity Database

    Lieskovská, Jaroslava; Kopecký, Jan

    2012-01-01

    Roč. 34, č. 1 (2012), s. 32-39 ISSN 0141-9838 R&D Projects: GA MŠk(CZ) LC06009 Institutional support: RVO:60077344 Keywords : Borrelia * dendritic cells * interferon signalling * tick saliva Subject RIV: EC - Immunology Impact factor: 2.208, year: 2012

  20. Activated protein synthesis and suppressed protein breakdown signaling in skeletal muscle of critically ill patients.

    Directory of Open Access Journals (Sweden)

    Jakob G Jespersen

    Full Text Available BACKGROUND: Skeletal muscle mass is controlled by myostatin and Akt-dependent signaling on mammalian target of rapamycin (mTOR, glycogen synthase kinase 3β (GSK3β and forkhead box O (FoxO pathways, but it is unknown how these pathways are regulated in critically ill human muscle. To describe factors involved in muscle mass regulation, we investigated the phosphorylation and expression of key factors in these protein synthesis and breakdown signaling pathways in thigh skeletal muscle of critically ill intensive care unit (ICU patients compared with healthy controls. METHODOLOGY/PRINCIPAL FINDINGS: ICU patients were systemically inflamed, moderately hyperglycemic, received insulin therapy, and showed a tendency to lower plasma branched chain amino acids compared with controls. Using Western blotting we measured Akt, GSK3β, mTOR, ribosomal protein S6 kinase (S6k, eukaryotic translation initiation factor 4E binding protein 1 (4E-BP1, and muscle ring finger protein 1 (MuRF1; and by RT-PCR we determined mRNA expression of, among others, insulin-like growth factor 1 (IGF-1, FoxO 1, 3 and 4, atrogin1, MuRF1, interleukin-6 (IL-6, tumor necrosis factor α (TNF-α and myostatin. Unexpectedly, in critically ill ICU patients Akt-mTOR-S6k signaling was substantially higher compared with controls. FoxO1 mRNA was higher in patients, whereas FoxO3, atrogin1 and myostatin mRNAs and MuRF1 protein were lower compared with controls. A moderate correlation (r2=0.36, p<0.05 between insulin infusion dose and phosphorylated Akt was demonstrated. CONCLUSIONS/SIGNIFICANCE: We present for the first time muscle protein turnover signaling in critically ill ICU patients, and we show signaling pathway activity towards a stimulation of muscle protein synthesis and a somewhat inhibited proteolysis.

  1. Dietary gossypol suppressed postprandial TOR signaling and elevated ER stress pathways in turbot (Scophthalmus maximus L.).

    Science.gov (United States)

    Bian, Fuyun; Jiang, Haowen; Man, Mingsan; Mai, Kangsen; Zhou, Huihui; Xu, Wei; He, Gen

    2017-01-01

    Gossypol is known to be a polyphenolic compound toxic to animals. However, its molecular targets are far from fully characterized. To evaluate the physiological and molecular effects of gossypol, we chose turbot (Scophthalmus maximus L.), a carnivorous fish, as our model species. Juvenile turbots (7.83 ± 0.02 g) were fed diets containing gradient levels of gossypol at 0 (G0), 600 (G1), and 1,200 (G2) mg/kg diets for 11 wk. After the feeding trial, fish growth, body protein, and fat contents were significantly reduced in the G2 group compared with those of the G0 group (P TOR) signaling and induced endoplasmic reticulum (ER) stress pathway in both the feeding experiment and cell cultures. Our results demonstrated that gossypol inhibited TOR signaling and elevated ER stress pathways both in vivo and in vitro, thus providing new mechanism of action of gossypol in nutritional physiology. Copyright © 2017 the American Physiological Society.

  2. Adaptive Locally Optimum Processing for Interference Suppression from Communication and Undersea Surveillance Signals

    Science.gov (United States)

    1994-07-01

    the signal can be reconstructed - + by forming; under the assumption that proju(s) = IsI costo and A0 - A A1+k] z1 proju(n) = InI cosx with 4 and W...state probability. A-2 2+T+p(-))+ Pk() C2 a. b b c b remaining states P2 -(Lc(b - a) + ac +PHa(b - c)) + L p(02) -, &2 abc remaining sLates -rk P 2 .abe

  3. Sonic Hedgehog Signaling Drives Mitochondrial Fragmentation by Suppressing Mitofusins in Cerebellar Granule Neuron Precursors and Medulloblastoma.

    Science.gov (United States)

    Malhotra, Anshu; Dey, Abhinav; Prasad, Niyathi; Kenney, Anna Marie

    2016-01-01

    Sonic hedgehog (Shh) signaling is closely coupled with bioenergetics of medulloblastoma, the most common malignant pediatric brain tumor. Shh-associated medulloblastoma arises from cerebellar granule neuron precursors (CGNP), a neural progenitor whose developmental expansion requires signaling by Shh, a ligand secreted by the neighboring Purkinje neurons. Previous observations show that Shh signaling inhibits fatty acid oxidation although driving increased fatty acid synthesis. Proliferating CGNPs and mouse Shh medulloblastomas feature high levels of glycolytic enzymes in vivo and in vitro. Because both of these metabolic processes are closely linked to mitochondrial bioenergetics, the role of Shh signaling in mitochondrial biogenesis was investigated. This report uncovers a surprising decrease in mitochondrial membrane potential (MMP) and overall ATP production in CGNPs exposed to Shh, consistent with increased glycolysis resulting in high intracellular acidity, leading to mitochondrial fragmentation. Ultrastructural examination of mitochondria revealed a spherical shape in Shh-treated cells, in contrast to the elongated appearance in vehicle-treated postmitotic cells. Expression of mitofusin 1 and 2 was reduced in these cells, although their ectopic expression restored the MMP to the nonproliferating state and the morphology to a fused, interconnected state. Mouse Shh medulloblastoma cells featured drastically impaired mitochondrial morphology, restoration of which by ectopic mitofusin expression was also associated with a decrease in the expression of Cyclin D2 protein, a marker for proliferation. This report exposes a novel role for Shh in regulating mitochondrial dynamics and rescue of the metabolic profile of tumor cells to that of nontransformed, nonproliferating cells and represents a potential avenue for development of medulloblastoma therapeutics. ©2015 American Association for Cancer Research.

  4. Circuit for echo and noise suppression of accoustic signals transmitted through a drill string

    Science.gov (United States)

    Drumheller, Douglas S.; Scott, Douglas D.

    1993-01-01

    An electronic circuit for digitally processing analog electrical signals produced by at least one acoustic transducer is presented. In a preferred embodiment of the present invention, a novel digital time delay circuit is utilized which employs an array of First-in-First-out (FiFo) microchips. Also, a bandpass filter is used at the input to this circuit for isolating drill string noise and eliminating high frequency output.

  5. Circuit for echo and noise suppression of acoustic signals transmitted through a drill string

    Science.gov (United States)

    Drumheller, D.S.; Scott, D.D.

    1993-12-28

    An electronic circuit for digitally processing analog electrical signals produced by at least one acoustic transducer is presented. In a preferred embodiment of the present invention, a novel digital time delay circuit is utilized which employs an array of First-in-First-out (FiFo) microchips. Also, a bandpass filter is used at the input to this circuit for isolating drill string noise and eliminating high frequency output. 20 figures.

  6. Recovering fNIRS brain signals: physiological interference suppression with independent component analysis

    Science.gov (United States)

    Zhang, Y.; Shi, M.; Sun, J.; Yang, C.; Zhang, Yajuan; Scopesi, F.; Makobore, P.; Chin, C.; Serra, G.; Wickramasinghe, Y. A. B. D.; Rolfe, P.

    2015-02-01

    Brain activity can be monitored non-invasively by functional near-infrared spectroscopy (fNIRS), which has several advantages in comparison with other methods, such as flexibility, portability, low cost and fewer physical restrictions. However, in practice fNIRS measurements are often contaminated by physiological interference arising from cardiac contraction, breathing and blood pressure fluctuations, thereby severely limiting the utility of the method. Hence, further improvement is necessary to reduce or eliminate such interference in order that the evoked brain activity information can be extracted reliably from fNIRS data. In the present paper, the multi-distance fNIRS probe configuration has been adopted. The short-distance fNIRS measurement is treated as the virtual channel and the long-distance fNIRS measurement is treated as the measurement channel. Independent component analysis (ICA) is employed for the fNIRS recordings to separate the brain signals and the interference. Least-absolute deviation (LAD) estimator is employed to recover the brain activity signals. We also utilized Monte Carlo simulations based on a five-layer model of the adult human head to evaluate our methodology. The results demonstrate that the ICA algorithm has the potential to separate physiological interference in fNIRS data and the LAD estimator could be a useful criterion to recover the brain activity signals.

  7. A20 restricts wnt signaling in intestinal epithelial cells and suppresses colon carcinogenesis.

    Directory of Open Access Journals (Sweden)

    Ling Shao

    Full Text Available Colon carcinogenesis consists of a multistep process during which a series of genetic and epigenetic adaptations occur that lead to malignant transformation. Here, we have studied the role of A20 (also known as TNFAIP3, a ubiquitin-editing enzyme that restricts NFκB and cell death signaling, in intestinal homeostasis and tumorigenesis. We have found that A20 expression is consistently reduced in human colonic adenomas than in normal colonic tissues. To further investigate A20's potential roles in regulating colon carcinogenesis, we have generated mice lacking A20 specifically in intestinal epithelial cells and interbred these with mice harboring a mutation in the adenomatous polyposis coli gene (APC(min. While A20(FL/FL villin-Cre mice exhibit uninflamed intestines without polyps, A20(FL/FL villin-Cre APC(min/+ mice contain far greater numbers and larger colonic polyps than control APC(min mice. We find that A20 binds to the β-catenin destruction complex and restricts canonical wnt signaling by supporting ubiquitination and degradation of β-catenin in intestinal epithelial cells. Moreover, acute deletion of A20 from intestinal epithelial cells in vivo leads to enhanced expression of the β-catenin dependent genes cyclinD1 and c-myc, known promoters of colon cancer. Taken together, these findings demonstrate new roles for A20 in restricting β-catenin signaling and preventing colon tumorigenesis.

  8. Aspirin suppresses the abnormal lipid metabolism in liver cancer cells via disrupting an NFκB-ACSL1 signaling.

    Science.gov (United States)

    Yang, Guang; Wang, Yuan; Feng, Jinyan; Liu, Yunxia; Wang, Tianjiao; Zhao, Man; Ye, Lihong; Zhang, Xiaodong

    2017-05-06

    Abnormal lipid metabolism is a hallmark of tumorigenesis. Hence, the alterations of metabolism enhance the development of hepatocellular carcinoma (HCC). Aspirin is able to inhibit the growth of cancers through targeting nuclear factor κB (NF-κB). However, the role of aspirin in disrupting abnormal lipid metabolism in HCC remains poorly understood. In this study, we report that aspirin can suppress the abnormal lipid metabolism of HCC cells through inhibiting acyl-CoA synthetase long-chain family member 1 (ACSL1), a lipid metabolism-related enzyme. Interestingly, oil red O staining showed that aspirin suppressed lipogenesis in HepG2 cells and Huh7 cells in a dose-dependent manner. In addition, aspirin attenuated the levels of triglyceride and cholesterol in the cells, respectively. Strikingly, we identified that aspirin was able to down-regulate ACSL1 at the levels of mRNA and protein. Moreover, we validated that aspirin decreased the nuclear levels of NF-κB in HepG2 cells. Mechanically, PDTC, an inhibitor of NF-κB, could down-regulate ACSL1 at the levels of mRNA and protein in the cells. Functionally, PDTC reduced the levels of lipid droplets, triglyceride and cholesterol in HepG2 cells. Thus, we conclude that aspirin suppresses the abnormal lipid metabolism in HCC cells via disrupting an NFκB-ACSL1 signaling. Our finding provides new insights into the mechanism by which aspirin inhibits abnormal lipid metabolism of HCC. Therapeutically, aspirin is potentially available for HCC through controlling abnormal lipid metabolism. Copyright © 2017. Published by Elsevier Inc.

  9. North American ginseng (Panax quinquefolius) suppresses β-adrenergic-dependent signalling, hypertrophy, and cardiac dysfunction.

    Science.gov (United States)

    Tang, Xilan; Gan, Xiaohong Tracey; Rajapurohitam, Venkatesh; Huang, Cathy Xiaoling; Xue, Jenny; Lui, Edmund M K; Karmazyn, Morris

    2016-12-01

    There is increasing evidence for a beneficial effect of ginseng on cardiac pathology. Here, we determined whether North American ginseng can modulate the deleterious effects of the β-adrenoceptor agonist isoproterenol on cardiac hypertrophy and function using in vitro and in vivo approaches. Isoproterenol was administered for 2 weeks at either 25 mg/kg per day or 50 mg/kg per day (ISO25 or ISO50) via a subcutaneously implanted osmotic mini-pump to either control rats or those receiving ginseng (0.9 g/L in the drinking water ad libitum). Isoproterenol produced time- and dose-dependent left ventricular dysfunction, although these effects were attenuated by ginseng. Improved cardiac functions were associated with reduced heart masses, as well as prevention in the upregulation of the hypertrophy-related fetal gene expression. Lung masses were similarly attenuated, suggesting reduced pulmonary congestion. In in vitro studies, ginseng (10 μg/mL) completely suppressed the hypertrophic response to 1 μmol/L isoproterenol in terms of myocyte surface area, as well as reduction in the upregulation of fetal gene expression. These effects were associated with attenuation in both protein kinase A and cAMP response element-binding protein phosphorylation. Ginseng attenuates adverse cardiac adrenergic responses and, therefore, may be an effective therapy to reduce hypertrophy and heart failure associated with excessive catecholamine production.

  10. Cepharanthine attenuates lipopolysaccharide-induced mice mastitis by suppressing the NF-κB signaling pathway.

    Science.gov (United States)

    Ershun, Zhou; Yunhe, Fu; Zhengkai, Wei; Yongguo, Cao; Naisheng, Zhang; Zhengtao, Yang

    2014-04-01

    Cepharanthine (CEP), a biscoclaurine alkaloid isolated from Stephania cepharantha Hayata, has been reported to have potent anti-inflammatory properties. However, the anti-inflammatory effects of CEP on a mouse model of lipopolysaccharide (LPS)-induced mastitis and its underlying molecular mechanisms remain to be elucidated. The purpose of the present study was to investigate the effects of CEP on LPS-induced mouse mastitis. The mouse model of mastitis was induced by inoculation of LPS through the canals of the mammary gland. CEP was administered intraperitoneally at 1 h before and 12 h after induction of LPS. The results show that CEP significantly attenuates the infiltration of neutrophils, suppresses myeloperoxidase activity, and reduces the levels of TNF-α, IL-1β, and IL-6 in LPS-induced mouse mastitis. Furthermore, CEP inhibited the phosphorylation of NF-κB p65 subunit and the degradation of its inhibitor IκBα. All the results suggest that CEP exerts potent anti-inflammatory effects on LPS-induced mouse mastitis. Accordingly, CEP might be a potential therapeutic agent for mastitis.

  11. Ginkgolide C Suppresses Adipogenesis in 3T3-L1 Adipocytes via the AMPK Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Chian-Jiun Liou

    2015-01-01

    Full Text Available Ginkgolide C, isolated from Ginkgo biloba leaves, is a flavone reported to have multiple biological functions, from decreased platelet aggregation to ameliorating Alzheimer disease. The study aim was to evaluate the antiadipogenic effect of ginkgolide C in 3T3-L1 adipocytes. Ginkgolide C was used to treat differentiated 3T3-L1 cells. Cell supernatant was collected to assay glycerol release, and cells were lysed to measure protein and gene expression related to adipogenesis and lipolysis by western blot and real-time PCR, respectively. Ginkgolide C significantly suppressed lipid accumulation in differentiated adipocytes. It also decreased adipogenesis-related transcription factor expression, including peroxisome proliferator-activated receptor and CCAAT/enhancer-binding protein. Furthermore, ginkgolide C enhanced adipose triglyceride lipase and hormone-sensitive lipase production for lipolysis and increased phosphorylation of AMP-activated protein kinase (AMPK, resulting in decreased activity of acetyl-CoA carboxylase for fatty acid synthesis. In coculture with an AMPK inhibitor (compound C, ginkgolide C also improved activation of sirtuin 1 and phosphorylation of AMPK in differentiated 3T3-L1 cells. The results suggest that ginkgolide C is an effective flavone for increasing lipolysis and inhibiting adipogenesis in adipocytes through the activated AMPK pathway.

  12. CAV1 inhibits metastatic potential in melanomas through suppression of the integrin/Src/FAK signaling pathway.

    Science.gov (United States)

    Trimmer, Casey; Whitaker-Menezes, Diana; Bonuccelli, Gloria; Milliman, Janet N; Daumer, Kristin M; Aplin, Andrew E; Pestell, Richard G; Sotgia, Federica; Lisanti, Michael P; Capozza, Franco

    2010-10-01

    Caveolin-1 (CAV1) is the main structural component of caveolae, which are plasma membrane invaginations that participate in vesicular trafficking and signal transduction events. Although evidence describing the function of CAV1 in several cancer types has recently accumulated, its role in melanoma tumor formation and progression remains poorly explored. Here, by using B16F10 melanoma cells as an experimental system, we directly explore the function of CAV1 in melanoma tumor growth and metastasis. We first show that CAV1 expression promotes proliferation, whereas it suppresses migration and invasion of B16F10 cells in vitro. When orthotopically implanted in the skin of mice, B16F10 cells expressing CAV1 form tumors that are similar in size to their control counterparts. An experimental metastasis assay shows that CAV1 expression suppresses the ability of B16F10 cells to form lung metastases in C57Bl/6 syngeneic mice. Additionally, CAV1 protein and mRNA levels are found to be significantly reduced in human metastatic melanoma cell lines and human tissue from metastatic lesions. Finally, we show that following integrin activation, B16F10 cells expressing CAV1 display reduced expression levels and activity of FAK and Src proteins. Furthermore, CAV1 expression markedly reduces the expression of integrin β(3) in B16F10 melanoma cells. In summary, our findings provide experimental evidence that CAV1 may function as an antimetastatic gene in malignant melanoma. © 2010 AACR.

  13. Identification of an Intracranial Pressure (ICP) Response Function from Continuously Acquired Electroencephalographic and ICP Signals in Burst-Suppressed Patients.

    Science.gov (United States)

    Connolly, Mark; Liou, Raymond; Vespa, Paul; Hu, Xiao

    2016-01-01

    Continuous intracranial pressure (ICP) and electroencephalographic (EEG) monitoring are used in the management of patients with brain injury. It is possible that these two signals could be related through neurovascular coupling. To explore this mechanism, we modeled the ICP response to brain activity by treating spontaneous burst activity in burst-suppressed patients as an impulse, and identified the ICP response function (ICPRF) as the subsequent change in ICP.Segments of ICP were filtered, classified as elevating or stable, and suitable ICPRFs were identified. After calibration, each ICPRF was convolved with the EEG to produce the estimated ICP. The mean error (ME) versus distance from the selected ICPRF was calculated and the elevating and stable ICP segments compared.Eighty-four ICPRFs were identified from 15 data segments. The ME of the elevating segments increased at an average rate of 57 mmHg/min, whereas the average ME of the stable segments increased at a rate of 0.05 mmHg/min.These findings demonstrate that deriving an ICPRF from a burst-suppressed patient is a suitable approach for stable segments. To completely model the ICP response to EEG activity, a more robust model should be developed.

  14. Celastrol inhibits chondrosarcoma proliferation, migration and invasion through suppression CIP2A/c-MYC signaling pathway

    Directory of Open Access Journals (Sweden)

    Jinhui Wu

    2017-05-01

    Full Text Available Chondrosarcomas (CS is the second most frequent tumors of cartilage origin. A small compound extracted from Thunder God Vine (Tripterygium wilfordii Hook. F. called celastrol can directly bound CIP2A protein and effectively inhibit cell proliferation and induce apoptosis in several cancer cells. However, little knowledge is concern about the important role of CIP2A in CS patients and the therapeutic value of celastrol on CS. Our results showed that CIP2A and c-MYC were verified to be oncoproteins by detecting their mRNA and protein expression in 10 human CS tissues by qRT-PCR and Western blots. After treatment of celastrol, the proliferation, migration and invasion were significantly inhibited; whereas the apoptosis was largely induced in human CS cell lines. In addition, celastrol inhibited the expression of CIP2A, c-MYC, and suppressed apoptotic proteins BAX and caspase-8 in human CS cells, on the other hand, it induced the expression of antiapoptotic protein Bcl-2. Finally, knockdown of CIP2A also inhibited the migration and invasion and induced apoptosis of human CS cells. To sum up, we found that celastrol had effects on inhibiting proliferation, migration, invasion and inducing apoptosis through suppression CIP2A/c-MYC signaling pathway in vitro, which may provide a new therapeutic regimen for CS.

  15. Activation of Brain Somatostatin Signaling Suppresses CRF Receptor-Mediated Stress Response

    Directory of Open Access Journals (Sweden)

    Andreas Stengel

    2017-04-01

    Full Text Available Corticotropin-releasing factor (CRF is the hallmark brain peptide triggering the response to stress and mediates—in addition to the stimulation of the hypothalamus-pituitary-adrenal (HPA axis—other hormonal, behavioral, autonomic and visceral components. Earlier reports indicate that somatostatin-28 injected intracerebroventricularly counteracts the acute stress-induced ACTH and catecholamine release. Mounting evidence now supports that activation of brain somatostatin signaling exerts a broader anti-stress effect by blunting the endocrine, autonomic, behavioral (with a focus on food intake and visceral gastrointestinal motor responses through the involvement of distinct somatostatin receptor subtypes.

  16. Chronic intermittent hypoxia induces NMDA receptor-dependent plasticity and suppresses nitric oxide signaling in the mouse hypothalamic paraventricular nucleus.

    Science.gov (United States)

    Coleman, Christal G; Wang, Gang; Park, Laibaik; Anrather, Josef; Delagrammatikas, George J; Chan, June; Zhou, Joan; Iadecola, Costantino; Pickel, Virginia M

    2010-09-08

    Chronic intermittent hypoxia (CIH) is a concomitant of sleep apnea that produces a slowly developing chemosensory-dependent blood pressure elevation ascribed in part to NMDA receptor-dependent plasticity and reduced nitric oxide (NO) signaling in the carotid body. The hypothalamic paraventricular nucleus (PVN) is responsive to hypoxic stress and also contains neurons that express NMDA receptors and neuronal nitric oxide synthase (nNOS). We tested the hypothesis that extended (35 d) CIH results in a decrease in the surface/synaptic availability of the essential NMDA NR1 subunit in nNOS-containing neurons and NMDA-induced NO production in the PVN of mice. As compared with controls, the 35 d CIH-exposed mice showed a significant increase in blood pressure and an increased density of NR1 immunogold particles located in the cytoplasm of nNOS-containing dendrites. Neither of these between-group differences was seen after 14 d, even though there was already a reduction in the NR1 plasmalemmal density at this time point. Patch-clamp recording of PVN neurons in slices showed a significant reduction in NMDA currents after either 14 or 35 d exposure to CIH compared with sham controls. In contrast, NO production, as measured by the NO-sensitive fluorescent dye 4-amino-5-methylamino-2',7'-difluorofluorescein, was suppressed only in the 35 d CIH group. We conclude that CIH produces a reduction in the surface/synaptic targeting of NR1 in nNOS neurons and decreases NMDA receptor-mediated currents in the PVN before the emergence of hypertension, the development of which may be enabled by suppression of NO signaling in this brain region.

  17. Andrographolide Suppress Tumor Growth by Inhibiting TLR4/NF-κB Signaling Activation in Insulinoma

    Science.gov (United States)

    Zhang, Qian-Qian; Ding, Yi; Lei, Yan; Qi, Cui-Ling; He, Xiao-Dong; Lan, Tian; Li, Jiang-Chao; Gong, Ping; Yang, Xuesong; Geng, Jian-Guo; Wang, Li-Jing

    2014-01-01

    Insulinomas are rare tumors, and approximately 10% of insulinomas are malignant. Accumulating evidence has implicated that we still lack effective therapy to treat the patients who are diagnosed with rare malignant insulinoma. Previous studies have reported that Andrographolide (Andro) could inhibit cell cycle progression, reduce cell invasion and induce cell apoptosis in many common cancer cells. However, the effects of andro are cell type-dependent. So we emplored the β-TC-6 cells and the RIP1-Tag2 transgenic mouse model of endogenously growing insulinoma model to elucidate the possible anti-cancer effect of Andro on insulinoma, an uncommon type of malignant cancers in this study. Our experiments revealed that Andro significantly inhibited tumor growth at both the early-stage and the advanced-stage of insulinoma through targeting the TLR4/NF-κB signaling pathway. This work initially provides the evidence that the TLR4/NF-κB signaling pathway might be vital as a potential therapeutic target, and also indispensable in Andro-mediated anti-cancer effect in insulinoma. PMID:24719558

  18. The suppression of ghrelin signaling mitigates age‐associated thermogenic impairment.

    Science.gov (United States)

    Lin, Ligen; Lee, Jong Han; Bongmba, Odelia Y N; Ma, Xiaojun; Zhu, Xiongwei; Sheikh-Hamad, David; Sun, Yuxiang

    2014-12-01

    Aging is associated with severe thermogenic impairment, which contributes to obesity and diabetes in aging. We previously reported that ablation of the ghrelin receptor, growth hormone secretagogue receptor (GHS‐R), attenuates age‐associated obesity and insulin resistance. Ghrelin and obestatin are derived from the same preproghrelin gene. Here we showed that in brown adipocytes, ghrelin decreases the expression of thermogenic regulator but obestatin increases it, thus showing the opposite effects. We also found that during aging, plasma ghrelin and GHS‐R expression in brown adipose tissue (BAT) are increased, but plasma obestatin is unchanged. Increased plasma ghrelin and unchanged obestatin during aging may lead to an imbalance of thermogenic regulation, which may in turn exacerbate thermogenic impairment in aging. Moreover, we found that GHS‐R ablation activates thermogenic signaling, enhances insulin activation, increases mitochondrial biogenesis, and improves mitochondrial dynamics of BAT. In addition, we detected increased norepinephrine in the circulation, and observed that GHS‐R knockdown in brown adipocytes directly stimulates thermogenic activity, suggesting that GHS‐R regulates thermogenesis via both central and peripheral mechanisms.Collectively, our studies demonstrate that ghrelin signaling is an important thermogenic regulator in aging. Antagonists of GHS‐R may serve as unique anti‐obesity agents, combating obesity by activating thermogenesis.

  19. The suppression of ghrelin signaling mitigates age-associated thermogenic impairment

    Science.gov (United States)

    Bongmba, Odelia Y. N.; Ma, Xiaojun; Zhu, Xiongwei; Sheikh-Hamad, David; Sun, Yuxiang

    2014-01-01

    Aging is associated with severe thermogenic impairment, which contributes to obesity and diabetes in aging. We previously reported that ablation of the ghrelin receptor, growth hormone secretagogue receptor (GHS-R), attenuates age-associated obesity and insulin resistance. Ghrelin and obestatin are derived from the same preproghrelin gene. Here we showed that in brown adipocytes, ghrelin decreases the expression of thermogenic regulator but obestatin increases it, thus showing the opposite effects. We also found that during aging, plasma ghrelin and GHS-R expression in brown adipose tissue (BAT) are increased, but plasma obestatin is unchanged. Increased plasma ghrelin and unchanged obestatin during aging may lead to an imbalance of thermogenic regulation, which may in turn exacerbate thermogenic impairment in aging. Moreover, we found that GHS-R ablation activates thermogenic signaling, enhances insulin activation, increases mitochondrial biogenesis, and improves mitochondrial dynamics of BAT. In addition, we detected increased norepinephrine in the circulation, and observed that GHS-R knockdown in brown adipocytes directly stimulates thermogenic activity, suggesting that GHS-R regulates thermogenesis via both central and peripheral mechanisms. Collectively, our studies demonstrate that ghrelin signaling is an important thermogenic regulator in aging. Antagonists of GHS-R may serve as unique anti-obesity agents, combating obesity by activating thermogenesis. PMID:25543537

  20. Andrographolide suppress tumor growth by inhibiting TLR4/NF-κB signaling activation in insulinoma.

    Science.gov (United States)

    Zhang, Qian-Qian; Ding, Yi; Lei, Yan; Qi, Cui-Ling; He, Xiao-Dong; Lan, Tian; Li, Jiang-Chao; Gong, Ping; Yang, Xuesong; Geng, Jian-Guo; Wang, Li-Jing

    2014-01-01

    Insulinomas are rare tumors, and approximately 10% of insulinomas are malignant. Accumulating evidence has implicated that we still lack effective therapy to treat the patients who are diagnosed with rare malignant insulinoma. Previous studies have reported that Andrographolide (Andro) could inhibit cell cycle progression, reduce cell invasion and induce cell apoptosis in many common cancer cells. However, the effects of andro are cell type-dependent. So we emplored the β-TC-6 cells and the RIP1-Tag2 transgenic mouse model of endogenously growing insulinoma model to elucidate the possible anti-cancer effect of Andro on insulinoma, an uncommon type of malignant cancers in this study. Our experiments revealed that Andro significantly inhibited tumor growth at both the early-stage and the advanced-stage of insulinoma through targeting the TLR4/NF-κB signaling pathway. This work initially provides the evidence that the TLR4/NF-κB signaling pathway might be vital as a potential therapeutic target, and also indispensable in Andro-mediated anti-cancer effect in insulinoma.

  1. Corilagin suppresses cholangiocarcinoma progression through Notch signaling pathway in vitro and in vivo.

    Science.gov (United States)

    Gu, Yue; Xiao, Linfeng; Ming, Yanlin; Zheng, Zhizhong; Li, Wengang

    2016-05-01

    Corilagin is a natural plant polyphenol tannic acid with antitumor, anti-inflammatory, and anti-oxidative properties. However, the mechanisms of its actions are largely unknown. Our group reported that corilagin could induce cell inhibition in human breast cancer cell line MCF-7 and human liver hepatocellular carcinoma cell lines HepG2. We report here that corilagin inhibits cholangiocarcinoma (CCA) development through regulating Notch signaling pathway. We found that, in vitro, corilagin inhibited CCA cell proliferation, migration and invasion, promoted CCA cell apoptosis, and inhibited Notch1 and Notch signaling pathway protein expression. Co-immunoprecipitation was used to establish Notch intracellular domain (NICD) interaction with MAML1 and P300 in CCA. Importantly, corilagin reduced Hes1 mRNA level through inhibiting Hes1 promoter activity. In nude mice, corilagin inhibited CCA growth and repressed the expression of Notch1 and mTOR. These results indicate that corilagin may control CCA cell growth by downregulating the expression of Notch1. Therefore, our findings suggest that corilagin may have the potential to become a new therapeutic drug for human CCA.

  2. Corilagin suppresses cholangiocarcinoma progression through Notch signaling pathway in vitro and in vivo

    Science.gov (United States)

    GU, YUE; XIAO, LINFENG; MING, YANLIN; ZHENG, ZHIZHONG; LI, WENGANG

    2016-01-01

    Corilagin is a natural plant polyphenol tannic acid with antitumor, anti-inflammatory, and anti-oxidative properties. However, the mechanisms of its actions are largely unknown. Our group reported that corilagin could induce cell inhibition in human breast cancer cell line MCF-7 and human liver hepatocellular carcinoma cell lines HepG2. We report here that corilagin inhibits cholangiocarcinoma (CCA) development through regulating Notch signaling pathway. We found that, in vitro, corilagin inhibited CCA cell proliferation, migration and invasion, promoted CCA cell apoptosis, and inhibited Notch1 and Notch signaling pathway protein expression. Co-immunoprecipitation was used to establish Notch intracellular domain (NICD) interaction with MAML1 and P300 in CCA. Importantly, corilagin reduced Hes1 mRNA level through inhibiting Hes1 promoter activity. In nude mice, corilagin inhibited CCA growth and repressed the expression of Notch1 and mTOR. These results indicate that corilagin may control CCA cell growth by downregulating the expression of Notch1. Therefore, our findings suggest that corilagin may have the potential to become a new therapeutic drug for human CCA. PMID:26935808

  3. Andrographolide Inhibits Ovariectomy-Induced Bone Loss via the Suppression of RANKL Signaling Pathways

    Science.gov (United States)

    Wang, Tao; Liu, Qian; Zhou, Lin; Yuan, Jin Bo; Lin, Xixi; Zeng, Rong; Liang, Xiaonan; Zhao, Jinmin; Xu, Jiake

    2015-01-01

    Osteoporosis is a debilitating skeletal disorder with an increased risk of low-energy fracture, which commonly occurs among postmenopausal women. Andrographolide (AP), a natural product isolated from Andrographis paniculata, has been found to have anti-inflammatory, anti-cancer, anti-asthmatic, and neuro-protective properties. However, its therapeutic effect on osteoporosis is unknown. In this study, an ovariectomy (OVX) mouse model was used to evaluate the therapeutic effects of AP on post-menopausal osteoporosis by using micro-computed tomography (micro-CT). Bone marrow-derived osteoclast culture was used to examine the inhibitory effect of AP on osteoclastogenesis. Real time PCR was employed to examine the effect of AP on the expression of osteoclast marker genes. The activities of transcriptional factors NF-κB and NFATc1 were evaluated using a luciferase reporter assay, and the IκBα protein level was analyzed by Western blot. We found that OVX mice treated with AP have greater bone volume (BV/TV), trabecular thickness (Tb.Th), and trabecular number (Tb.N) compared to vehicle-treated OVX mice. AP inhibited RANKL-induced osteoclastogenesis, the expression of osteoclast marker genes including cathepsin K (Ctsk), TRACP (Acp5), and NFATc1, as well as the transcriptional activities of NF-κB and NFATc1. In conclusion, our results suggest that AP inhibits estrogen deficiency-induced bone loss in mice via the suppression of RANKL-induced osteoclastogensis and NF-κB and NFATc1 activities and, thus, might have therapeutic potential for osteoporosis. PMID:26593901

  4. Andrographolide suppresses melanin synthesis through Akt/GSK3β/β-catenin signal pathway.

    Science.gov (United States)

    Zhu, Ping-Ya; Yin, Wei-Han; Wang, Meng-Ran; Dang, Yong-Yan; Ye, Xi-Yun

    2015-07-01

    Tyrosinase (TYR) is the key enzyme controlling the production of melanin. Very few papers have reported that andrographolide can inhibit melanin content. To investigate the effects of andrographolide on melanin synthesis. Cell viability, melanin content, TYR activity, transcriptional and protein expression levels of TYR family and other kinds of proteins involved in melanogenesis were measured after the treatments of andrographolide. It was found that andrographolide decreased melanin content, TYR activity and transcriptional and protein expression of TYR family and microphthalmia-associated transcription factor (MITF) in B16F10 melanoma cells. Data showed andrographolide also decreased melanin content and TYR content in ultraviolet B (UVB) irradiation induced brown guinea pigs. Moreover, we found that melanin content and TYR activity were effectively inhibited in Human Epidermis Melanocyte (HEM) treated with andrographolide at the medium concentrations without apparent effect on cell viability. Results in experiments treated with MG-132 or cycloheximide (CHX) showed that andrographolide lowered the content of β-catenin in cell nucleus resulting from accelerating the degradation of β-catenin. Phosphorylation of glycogen synthase kinase 3β (GSK3β) and Akt decreased simultaneously. 6-Bromoindirubin-3'-oxime (BIO, inhibitor of GSK3β) and insulin-like growth factors-1 (IGF-1, activator of Akt) could reverse the decline of β-catenin in B16F10 cells induced by andrographolide. These results demonstrate that andrographolide can effectively suppress melanin content and TYR activity in B16F10 cells, HEM cells and UVB-induced brown guinea pig skin by decreasing phosphorylation of GSK3β dependent on Akt, promoting the degradation of β-catenin, inhibiting β-catenin into the nucleus and decreasing the expression of MITF and TYR family. Data indicate that andrographolide may be a potential whiting agent which can have great market in cosmetics and in clinical such as

  5. Andrographolide Inhibits Ovariectomy-Induced Bone Loss via the Suppression of RANKL Signaling Pathways

    Directory of Open Access Journals (Sweden)

    Tao Wang

    2015-11-01

    Full Text Available Osteoporosis is a debilitating skeletal disorder with an increased risk of low-energy fracture, which commonly occurs among postmenopausal women. Andrographolide (AP, a natural product isolated from Andrographis paniculata, has been found to have anti-inflammatory, anti-cancer, anti-asthmatic, and neuro-protective properties. However, its therapeutic effect on osteoporosis is unknown. In this study, an ovariectomy (OVX mouse model was used to evaluate the therapeutic effects of AP on post-menopausal osteoporosis by using micro-computed tomography (micro-CT. Bone marrow-derived osteoclast culture was used to examine the inhibitory effect of AP on osteoclastogenesis. Real time PCR was employed to examine the effect of AP on the expression of osteoclast marker genes. The activities of transcriptional factors NF-κB and NFATc1 were evaluated using a luciferase reporter assay, and the IκBα protein level was analyzed by Western blot. We found that OVX mice treated with AP have greater bone volume (BV/TV, trabecular thickness (Tb.Th, and trabecular number (Tb.N compared to vehicle-treated OVX mice. AP inhibited RANKL-induced osteoclastogenesis, the expression of osteoclast marker genes including cathepsin K (Ctsk, TRACP (Acp5, and NFATc1, as well as the transcriptional activities of NF-κB and NFATc1. In conclusion, our results suggest that AP inhibits estrogen deficiency-induced bone loss in mice via the suppression of RANKL-induced osteoclastogensis and NF-κB and NFATc1 activities and, thus, might have therapeutic potential for osteoporosis.

  6. Nanostructure Secondary-Mirror Apodizing Mask for Transmitter Signal Suppression in a Duplex Telescope

    Science.gov (United States)

    Hagopian, John; Livas, Jeffrey; Shiri, Shahram; Getty, Stephanie; Tveekrem, June; Butler, James

    2012-01-01

    A document discusses a nanostructure apodizing mask, made of multi-walled carbon nanotubes, that is applied to the centers (or in and around the holes) of the secondary mirrors of telescopes that are used to interferometrically measure the strain of space-time in response to gravitational waves. The shape of this ultra-black mask can be adjusted to provide a smooth transition to the clear aperture of the secondary mirror to minimize diffracted light. Carbon nanotubes grown on silicon are a viable telescope mirror substrate, and can absorb significantly more light than other black treatments. The hemispherical reflectance of multi-walled carbon nanotubes grown at GSFC is approximately 3 to 10 times better than a standard aerospace paint used for stray light control. At the LISA (Laser Interferometer Space Antenna) wavelength of 1 micron, the advantage over paint is a factor of 10. Primarily, in the center of the secondary mirror (in the region of central obscuration, where no received light is lost) a black mask is applied to absorb transmitted light that could be reflected back into the receiver. In the LISA telescope, this is in the center couple of millimeters. The shape of this absorber is critical to suppress diffraction at the edge. By using the correct shape, the stray light can be reduced by approximately 10 to the 9 orders of magnitude versus no center mask. The effect of the nanotubes has been simulated in a stray-light model. The effect of the apodizing mask has been simulated in a near-field diffraction model. Specifications are geometry-dependent, but the baseline design for the LISA telescope has been modeled as well. The coatings are somewhat fragile, but work is continuing to enhance adhesion.

  7. Lithium Suppresses Hedgehog Signaling via Promoting ITCH E3 Ligase Activity and Gli1–SUFU Interaction in PDA Cells

    Directory of Open Access Journals (Sweden)

    Xinshuo Wang

    2017-11-01

    Full Text Available Dysregulation of Hedgehog (Hh signaling pathway is one of the hallmarks of pancreatic ductal adenocarcinoma (PDA. Lithium, a clinical mood stabilizer for the treatment of mental disorders, is known to suppress tumorigenic potential of PDA cells by targeting the Hh/Gli signaling pathway. In this study, we investigated the molecular mechanism of lithium induced down-regulation of Hh/Gli1. Our data show that lithium promotes the poly-ubiquitination and proteasome-mediated degradation of Gli1 through activating E3 ligase ITCH. Additionally, lithium enhances interaction between Gli1 and SUFU via suppressing GSK3β, which phosphorylates SUFU and destabilizes the SUFU-Gli1 inhibitory complex. Our studies illustrate a novel mechanism by which lithium suppresses Hh signaling via simultaneously promoting ITCH-dependent Gli1 ubiquitination/degradation and SUFU-mediated Gli1 inhibition.

  8. Bmi-1-targeting suppresses osteosarcoma aggressiveness through the NF-κB signaling pathway

    Science.gov (United States)

    Liu, Jiaguo; Luo, Bin; Zhao, Meng

    2017-01-01

    Bone cancer is one of the most lethal malignancies and the specific causes of tumor initiation are not well understood. B-cell-specific Moloney murine leukemia virus integration site 1 protein (Bmi-1) has been reported to be associated with the initiation and progression of osteosarcoma, and as a prognostic indicator in the clinic. In the current study, a full-length antibody targeting Bmi-1 (AbBmi-1) was produced and the preclinical value of Bmi-1-targeted therapy was evaluated in bone carcinoma cells and tumor xenograft mice. The results indicated that the Bmi-1 expression level was markedly upregulated in bone cancer cell lines, and inhibition of Bmi-1 by AbBmi-1 reduced the invasiveness and migration of osteosarcoma cells. Overexpression of Bmi-1 promoted proliferation and angiogenesis, and increased apoptosis resistance induced by cisplatin via the nuclear factor-κB (NF-κB) signal pathway. In addition, AbBmi-1 treatment inhibited the tumorigenicity of osteosarcoma cells in vivo. Furthermore, AbBmi-1 blocked NF-κB signaling and reduced MMP-9 expression. Furthermore, Bmi-1 promoted osteosarcoma tumor growth, whereas AbBmi-1 significantly inhibited osteosarcoma tumor growth in vitro and in vivo. Notably, AbBmi-1 decreased the percentages of Ki67-positive cells and terminal deoxynucleotidyl transferase dUTP nick end labeling-positive cells in tumors compared with Bmi-1-treated and PBS controls. Notably, MMP-9 and NF-κB expression were downregulated by treatment with AbBmi-1 in MG-63 osteosarcoma cells. In conclusion, the data provides evidence that AbBmi-1 inhibited the progression of osteosarcoma, suggesting that AbBmi-1 may be a novel anti-cancer agent through the inhibition of Bmi-1 via activating the NF-κB pathway in osteosarcoma. PMID:28983587

  9. CBX7 suppresses cell proliferation, migration, and invasion through the inhibition of PTEN/Akt signaling in pancreatic cancer.

    Science.gov (United States)

    Ni, Sujie; Wang, Hongwei; Zhu, Xiaolin; Wan, Chunhua; Xu, Junfei; Lu, Chen; Xiao, Li; He, Jiaqi; Jiang, Chongyi; Wang, Wei; He, Zhixian

    2017-01-31

    Chromobox protein homolog 7 (CBX7), one of the polycomb group (PcG) proteins, is a transcriptional repressor involved in the regulation of cell proliferation and senescence. In the present study, we showed that CBX7 negatively regulates the proliferation, viability, chemoresistance, and migration of pancreatic cancer cells. Overexpression of CBX7 significantly inhibited the proliferation of pancreatic cancer cells in vitro and in vivo. Depletion of CBX7 facilitated their growth. CBX7 also impaired the viability and chemoresistance of pancreatic cancer cells. Transwell assays showed that CBX7 reduces the migratory capacity of pancreatic cancer cells. Of note, CBX7 reduced PTEN/Akt signaling in pancreatic cancer cells by increasing PTEN transcription, suggesting involvement of PTEN/Akt pathway in the tumor suppressive activity of CBX7. In addition, immunohistochemical analysis the CBX7 and PTEN expression in 74 surgically resected pancreatic ductal adenocarcinoma (PDAC) specimens revealed that CBX7 expression is significantly downregulated in pancreatic ductal adenocarcinoma, compared to normal pancreatic tissues. Reduced expression of CBX7 and PTEN was associated with increased malignancy grade in pancreatic adenocarcinoma, whereas maintenance of CBX7 and PTEN expression showed a trend toward a longer survival. These findings suggest CBX7 is an important tumor suppressor that negatively modulates PTEN/Akt signaling during pancreatic tumorigenesis.

  10. Antroquinonol Targets FAK-Signaling Pathway Suppressed Cell Migration, Invasion, and Tumor Growth of C6 Glioma.

    Science.gov (United States)

    Thiyagarajan, Varadharajan; Tsai, May-Jywan; Weng, Ching-Feng

    2015-01-01

    Focal adhesion kinase (FAK) is a non-receptor protein tyrosine that is overexpressed in many types of tumors and plays a pivotal role in multiple cell signaling pathways involved in cell survival, migration, and proliferation. This study attempts to determine the effect of synthesized antroquinonol on the modulation of FAK signaling pathways and explore their underlying mechanisms. Antroquinonol significantly inhibits cell viability with an MTT assay in both N18 neuroblastoma and C6 glioma cell lines, which exhibits sub G1 phase cell cycle, and further induction of apoptosis is confirmed by a TUNEL assay. Antroquinonol decreases anti-apoptotic proteins, whereas it increases p53 and pro-apoptotic proteins. Alterations of cell morphology are observed after treatment by atomic force microscopy. Molecular docking results reveal that antroquinonol has an H-bond with the Arg 86 residue of FAK. The protein levels of Src, pSrc, FAK, pFAK, Rac1, and cdc42 are decreased after antroquinonol treatment. Additionally, antroquinonol also regulates the expression of epithelial to mesenchymal transition (EMT) proteins. Furthermore, antroquinonol suppresses the C6 glioma growth in xenograft studies. Together, these results suggest that antroquinonol is a potential anti-tumorigenesis and anti-metastasis inhibitor of FAK.

  11. Antroquinonol Targets FAK-Signaling Pathway Suppressed Cell Migration, Invasion, and Tumor Growth of C6 Glioma.

    Directory of Open Access Journals (Sweden)

    Varadharajan Thiyagarajan

    Full Text Available Focal adhesion kinase (FAK is a non-receptor protein tyrosine that is overexpressed in many types of tumors and plays a pivotal role in multiple cell signaling pathways involved in cell survival, migration, and proliferation. This study attempts to determine the effect of synthesized antroquinonol on the modulation of FAK signaling pathways and explore their underlying mechanisms. Antroquinonol significantly inhibits cell viability with an MTT assay in both N18 neuroblastoma and C6 glioma cell lines, which exhibits sub G1 phase cell cycle, and further induction of apoptosis is confirmed by a TUNEL assay. Antroquinonol decreases anti-apoptotic proteins, whereas it increases p53 and pro-apoptotic proteins. Alterations of cell morphology are observed after treatment by atomic force microscopy. Molecular docking results reveal that antroquinonol has an H-bond with the Arg 86 residue of FAK. The protein levels of Src, pSrc, FAK, pFAK, Rac1, and cdc42 are decreased after antroquinonol treatment. Additionally, antroquinonol also regulates the expression of epithelial to mesenchymal transition (EMT proteins. Furthermore, antroquinonol suppresses the C6 glioma growth in xenograft studies. Together, these results suggest that antroquinonol is a potential anti-tumorigenesis and anti-metastasis inhibitor of FAK.

  12. Cyanidin Chloride inhibits ovariectomy-induced osteoporosis by suppressing RANKL-mediated osteoclastogenesis and associated signaling pathways.

    Science.gov (United States)

    Cheng, Jianwen; Zhou, Lin; Liu, Qian; Tickner, Jennifer; Tan, Zhen; Li, Xiaofeng; Liu, Mei; Lin, Xixi; Wang, Tao; Pavlos, Nathan J; Zhao, Jinmin; Xu, Jiake

    2018-03-01

    Over-production and activation of osteoclasts is a common feature of osteolytic conditions such as osteoporosis, tumor-associated osteolysis, and inflammatory bone erosion. Cyanidin Chloride, a subclass of anthocyanin, displays antioxidant and anti-carcinogenesis properties, but its role in osteoclastic bone resorption and osteoporosis is not well understood. In this study, we showed that Cyanidin Chloride inhibits osteoclast formation, hydroxyapatite resorption, and receptor activator of NF-κB ligand (RANKL)-induced osteoclast marker gene expression; including ctr, ctsk, and trap. Further investigation revealed that Cyanidin Chloride inhibits RANKL-induced NF-κB activation, suppresses the degradation of IκB-α and attenuates the phosphorylation of extracellular signal-regulated kinases (ERK). In addition, Cyanidin Chloride abrogated RANKL-induced calcium oscillations, the activation of nuclear factor of activated T cells calcineurin-dependent 1 (NFATc1), and the expression of c-Fos. Further, we showed that Cyanidin Chloride protects against ovariectomy-induced bone loss in vivo. Together our findings suggest that Cyanidin Chloride is capable of inhibiting osteoclast formation, hydroxyapatite resorption and RANKL-induced signal pathways in vitro and OVX-induced bone loss in vivo, and thus might have therapeutic potential for osteolytic diseases. © 2017 Wiley Periodicals, Inc.

  13. Suppression of Rac1 Signaling by Influenza A Virus NS1 Facilitates Viral Replication

    Science.gov (United States)

    Jiang, Wei; Sheng, Chunjie; Gu, Xiuling; Liu, Dong; Yao, Chen; Gao, Shijuan; Chen, Shuai; Huang, Yinghui; Huang, Wenlin; Fang, Min

    2016-01-01

    Influenza A virus (IAV) is a major human pathogen with the potential to become pandemic. IAV contains only eight RNA segments; thus, the virus must fully exploit the host cellular machinery to facilitate its own replication. In an effort to comprehensively characterize the host machinery taken over by IAV in mammalian cells, we generated stable A549 cell lines with over-expression of the viral non-structural protein (NS1) to investigate the potential host factors that might be modulated by the NS1 protein. We found that the viral NS1 protein directly interacted with cellular Rac1 and facilitated viral replication. Further research revealed that NS1 down-regulated Rac1 activity via post-translational modifications. Therefore, our results demonstrated that IAV blocked Rac1-mediated host cell signal transduction through the NS1 protein to facilitate its own replication. Our findings provide a novel insight into the mechanism of IAV replication and indicate new avenues for the development of potential therapeutic targets. PMID:27869202

  14. Wwox suppresses breast cancer cell growth through modulation of the hedgehog–GLI1 signaling pathway

    International Nuclear Information System (INIS)

    Xiong, Anwen; Wei, Li; Ying, Mingzhen; Wu, Hongmei; Hua, Jin; Wang, Yajie

    2014-01-01

    Highlights: • We investigated Gli1 as a novel partner of Wwox. • We observed a physical association between Wwox and the Gli1. • Wwox–Gli1 interaction affects Gli1 intracellular localization. • Gli1 Blocks Wwox-induced growth inhibition and apoptosis in T47D cells. - Abstract: Wwox is a tumor suppressor that is frequently deleted or altered in several cancer types, including breast cancer. Previous studies have shown that ectopic expression of Wwox inhibits proliferation of breast cancer cells. However, the underlying mechanism remains unclear. To better understand the molecular mechanisms of Wwox function, we investigated novel partners of this protein. Utilizing the coimmunoprecipitation assay, we observed a physical association between Wwox and the Gli1 zinc-finger transcription factor involved in the hedgehog pathway. Our results further demonstrated that Wwox expression triggered redistribution of nuclear Gli1 to the cytoplasm. Additionally, ectopic expression of Wwox reduced Gli1 expression in vitro. Furthermore, Gli1 Blocks Wwox-induced breast cancer cell growth inhibition. These findings suggest a functional crosstalk between Wwox and hedgehog–GLI1 signaling pathway in tumorigenesis

  15. Andrographolide suppresses epithelial mesenchymal transition by inhibition of MAPK signalling pathway in lens epithelial cells.

    Science.gov (United States)

    Kayastha, Forum; Johar, Kaid; Gajjar, Devarshi; Arora, Anshul; Madhu, Hardik; Ganatra, Darshini; Vasavada, Abhay

    2015-06-01

    Epithelial mesenchymal transition (EMT) of lens epithelial cells (LECs) may contribute to the development of posterior capsular opacification (PCO), which leads to visual impairment. Andrographolide has been shown to have therapeutic potential against various cancers. However, its effect on human LECs is still unknown. The purpose of this study is to evaluate the effect of andrographolide on EMT induced by growth factors in the fetal human lens epithelial cell line (FHL 124). Initially the LECs were treated with growth factors (TGF-beta 2 and bFGF) to induce EMT. Subsequently these EMT-induced cells were treated with andrographolide at 100 and 500 nM concentrations for 24 h. Our results showed that FHL 124 cells treated with growth factors had a significant decrease in protein and m-RNA levels of epithelial markers pax6 and E-Cadherin. After administering andrographolide, these levels significantly increased. It was noticed that EMT markers alpha-SMA, fibronectin and collagen IV significantly decreased after treatment with andrographolide when compared to the other group. Treatment with andrographolide significantly inhibited phosphorylation of ERK and JNK. Cell cycle analysis showed that andrographolide did not arrest cells at G0/G1 or G2/M at tested concentrations. Our findings suggest that andrographolide helps sustain epithelial characteristics by modulating EMT markers and inhibiting the mitogen-activated protein kinase (MAPK) signalling pathway in LECs. Hence it can prove to be useful in curbing EMT-mediated PCO.

  16. Ski regulates Smads and TAZ signaling to suppress lung cancer progression.

    Science.gov (United States)

    Xie, Mian; Wu, Xiaojun; Zhang, Jinjun; Zhang, Jiexia; Li, Xiangxiang

    2017-10-01

    Ski, the transforming protein of the avian Sloan-Kettering retrovirus, displays both pro- and anti-oncogenic activities in human cancer. The mechanisms underlying these conflicting observations have not been fully understood. Herein, we investigated the mechanism underlying the tumor suppressor activity of Ski. To investigate the effect of Ski re-activation on TGF-β and Hippo/TAZ pathway, we measured its effect on the endogenous Smad target genes (PAI-1 and P15 INK4B ) and TAZ target gene CTGF. The results revealed that Ski exerted its inhibitory activity in TGF-β1/Smad signaling pathway. Ski inhibited TAZ by increasing their phosphorylation by Lats2 and did not alter the localization of TAZ. Ski inhibited lung cancer growth and invasion. Ski methylation correlated with decreased mRNA expression in human lung cancer cell lines. Thus, Ski inhibited the function of TGF-β and TAZ through multiple mechanisms in human lung cancer. © 2017 Wiley Periodicals, Inc.

  17. Dusuqing granules (DSQ) suppress inflammation in Klebsiella pneumonia rat via NF-κB/MAPK signaling.

    Science.gov (United States)

    Mei, Xue; Wang, Hao-Xun; Li, Jian-Sheng; Liu, Xiao-Hui; Lu, Xiao-Fan; Li, Ya; Zhang, Wei-Yu; Tian, Yan-Ge

    2017-04-17

    Dusuqing granules (DSQ) have been used in the treatment of bacterial pneumonia clinically, with remarkable benefits. This study was initiated to explore the effects of DSQ on pulmonary inflammation by regulating nuclear factor (NF)-κB/mitogen-activated protein kinase (MAPK) signaling in bacterial pneumonia rats. Rat model was duplicated with Klebsiella pneumonia by a one-time intratracheal injection. Rats were randomized into control, model, DSQ and levofloxacin (LVX) groups. After administrated with appropriate medicines for 7 days, lung tissues were harvested and prepared for pathological analysis, and interleukin (IL)-1, IL-6, monocyte chemotactic protein (MCP)-1and macrophage inflammatory protein (MIP)-2 detections. NF-κB mRNA was measured by real-time qPCR, and the phosphorylation and total proteins of P38MAPK, JNK46/54, ERK42/44 were determined by Western blotting. Marked pathological impairments were observed in model rats, whereas were improved in DSQ group. The cytokines levels, NF-κB mRNA expression and the phosphorylation of P38MAPK, JNK46/54 and ERK42/44 proteins were significantly higher in model group, and were significantly depressed in DSQ group. The protective effects of DSQ on Klebsiella pneumonia might be attributed to its inactivative effects of NF-κB/ MAPK pathway.

  18. Wwox suppresses breast cancer cell growth through modulation of the hedgehog–GLI1 signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Anwen [Department of Oncology, Changhai Hospital, Second Military Medical University, Shanghai (China); Wei, Li [Department of Oncology, Changhai Hospital, Second Military Medical University, Shanghai (China); Department of Oncology, NO. 401 hospital of PLA, Qingdao, Shandong (China); Ying, Mingzhen; Wu, Hongmei; Hua, Jin [Department of Oncology, Changhai Hospital, Second Military Medical University, Shanghai (China); Wang, Yajie, E-mail: yajiewang@live.com [Department of Oncology, Changhai Hospital, Second Military Medical University, Shanghai (China)

    2014-01-24

    Highlights: • We investigated Gli1 as a novel partner of Wwox. • We observed a physical association between Wwox and the Gli1. • Wwox–Gli1 interaction affects Gli1 intracellular localization. • Gli1 Blocks Wwox-induced growth inhibition and apoptosis in T47D cells. - Abstract: Wwox is a tumor suppressor that is frequently deleted or altered in several cancer types, including breast cancer. Previous studies have shown that ectopic expression of Wwox inhibits proliferation of breast cancer cells. However, the underlying mechanism remains unclear. To better understand the molecular mechanisms of Wwox function, we investigated novel partners of this protein. Utilizing the coimmunoprecipitation assay, we observed a physical association between Wwox and the Gli1 zinc-finger transcription factor involved in the hedgehog pathway. Our results further demonstrated that Wwox expression triggered redistribution of nuclear Gli1 to the cytoplasm. Additionally, ectopic expression of Wwox reduced Gli1 expression in vitro. Furthermore, Gli1 Blocks Wwox-induced breast cancer cell growth inhibition. These findings suggest a functional crosstalk between Wwox and hedgehog–GLI1 signaling pathway in tumorigenesis.

  19. Lemur Tyrosine Kinase-3 Suppresses Growth of Prostate Cancer Via the AKT and MAPK Signaling Pathways

    Directory of Open Access Journals (Sweden)

    Pengcheng Sun

    2017-08-01

    Full Text Available Background/Aims: Lemur tyrosine kinase (LMTK-3 is a member of the receptor tyrosine kinase (RTK family. Abnormal expression of LMTK-3 exists in various types of cancers, especially in endocrine-resistant breast cancers; however, the precise level of expression and the biological function in prostate cancer are poorly understood. Methods: In the present study, we determined the expression of LMTK-3 in prostate cancer using immunohistochemistry and Western blotting. We infected PC3 and LNCaP cells with lentivirus-LMTK-3 and observed the biologic characteristics of the PC3 and LNCaP cells in vitro with TUNEL, and migration and invasion assays, respectively. We also established a transplant tumor model of human prostate cancer with infected cells in 15 BALB/c-nu/nu nude mice. Results: LMTK-3 was expressed in prostate epithelial cells. There was a significant decline in the level of LMTK-3 expression in prostate cancers compared to normal tissues. LMTK-3 inhibited PC3 and LNCaP cell growth, migration, and invasion, and induced cell apoptosis in vitro. We also observed that LMTK-3 induced PC3 cell apoptosis in vivo. Further study showed that LMTK-3 inhibited phosphorylation of AKT and ERK, and promoted phosphorylation and activation of p38 kinase and Jun kinase (JNK. Conclusion: Recombinant lentivirus with enhanced expression of LMTK-3 inhibited prostate cancer cell growth and induced apoptosis in vitro and in vivo. AKT and MAPK signaling pathways may contribute to the process.

  20. Bajijiasu Abrogates Osteoclast Differentiation via the Suppression of RANKL Signaling Pathways through NF-κB and NFAT

    Directory of Open Access Journals (Sweden)

    Guoju Hong

    2017-01-01

    Full Text Available Pathological osteolysis is commonly associated with osteoporosis, bone tumors, osteonecrosis, and chronic inflammation. It involves excessive resorption of bone matrix by activated osteoclasts. Suppressing receptor activator of NF-κB ligand (RANKL signaling pathways has been proposed to be a good target for inhibiting osteoclast differentiation and bone resorption. Bajijiasu—a natural compound derived from Morinda officinalis F. C. How—has previously been shown to have anti-oxidative stress property; however, its effect and molecular mechanism of action on osteoclastogenesis and bone resorption remains unclear. In the present study, we found that Bajijiasu dose-dependently inhibited RANKL-induced osteoclast formation and bone resorption from 0.1 mM, and reached half maximal inhibitory effects (IC50 at 0.4 mM without toxicity. Expression of RANKL-induced osteoclast specific marker genes including cathepsin K (Ctsk, nuclear factor of activated T-cells cytoplasmic 1 (NFATc1, tartrate resistant acid phosphatase (TRAcP, vacuolar-type H+-ATPase V0 subunit D2 (V-ATPase d2, and (matrix metalloproteinase-2 (MMP2 was inhibited by Bajijiasu treatment. Luciferase reporter gene studies showed that Bajijiasu could significantly reduce the expression and transcriptional activity of NFAT as well as RANKL-induced NF-κB activation in a dose-dependent manner. Further, Bajijiasu was found to decrease the RANKL-induced phosphorylation of extracellular signal-regulated kinases (ERK, inhibitor of κB-α (IκB-α, NFAT, and V-ATPase d2. Taken together, this study revealed Bajijiasu could attenuate osteoclast formation and bone resorption by mediating RANKL signaling pathways, indicative of a potential effect of Bajijiasu on osteolytic bone diseases.

  1. Suppression of microRNA-125a-5p upregulates the TAZ-EGFR signaling pathway and promotes retinoblastoma proliferation.

    Science.gov (United States)

    Zhang, Yiting; Xue, Chunyan; Zhu, Xiaomin; Zhu, Xinyue; Xian, Hongyu; Huang, Zhenping

    2016-08-01

    Retinoblastoma is the most common intraocular malignancy that occurs during childhood; however, the mechanism underlying retinoblastoma proliferation and progression remains unclear. MicroRNAs (miRNAs) play an important role in the regulation of a myriad of biological processes in various types of cancer. In this study, we performed microarray analysis followed by qRT-PCR using four classes of retinoblastoma tissues with increasing cTNM classification stages to identify crucial miRNAs whose expression was correlated with retinoblastoma progression. miR-125a-5p was downregulated, and its expression levels were inversely correlated with cell proliferation in retinoblastoma compared with adjacent non-tumor retinal tissues. The overexpression of miR-125a-5p significantly suppressed cell proliferation and tumor formation in retinoblastoma. We further identified the transcriptional co-activator with PDZ binding motif (TAZ) as a direct target of miR-125a-5p. Importantly, TAZ levels were inversely correlated with miRNA-125a-5p expression, and TAZ promoted retinoblastoma cell proliferation. Moreover, the overexpression of miR-125a-5p led to a decrease in TAZ expression and downstream EGFR signaling pathway activation both in vitro and vivo. Finally, TAZ overexpression in retinoblastoma cells overexpressing miR-125a-5p restored retinoblastoma cell proliferation and EGFR pathway activation. Taken together, our data demonstrated that miR-125a-5p functions as an important tumor suppressor that suppresses the EGFR pathway by targeting TAZ to inhibit tumor progression in retinoblastoma. Thus, the miR-125a-5p/TAZ/EGFR axis may be a potential therapeutic target for retinoblastoma. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. 4-1BB Signaling in Conventional T Cells Drives IL-2 Production That Overcomes CD4+CD25+FoxP3+ T Regulatory Cell Suppression.

    Directory of Open Access Journals (Sweden)

    Hampartsoum B Barsoumian

    Full Text Available Costimulation with the recombinant SA-4-1BBL agonist of 4-1BB receptor on conventional CD4+ T cells (Tconvs overcomes the suppression mediated by naturally occurring CD4+CD25+FoxP3+ T regulatory cells (Tregs. The mechanistic basis of this observation has remained largely unknown. Herein we show that Tconvs, but not Tregs, are the direct target of SA-4-1BBL-mediated evasion of Treg suppression. IL-2 produced by Tconvs in response to 4-1BB signaling is both necessary and sufficient for overcoming Treg suppression. Supernatant from Tconvs stimulated with SA-4-1BBL contains high levels of IL-2 and overcomes Treg suppression in ex vivo Tconv:Treg cocultures. Removal of IL-2 from such supernatant restores Treg suppression and repletion of Tconv:Treg cocultures with exogenous recombinant IL-2 overcomes suppression. This study establishes 4-1BB signaling as a key circuit that regulates physical and functional equilibrium between Tregs and Tconvs with important implications for immunotherapy for indications where a fine balance between Tregs and Teffs plays a decisive role.

  3. BMI-1 suppression increases the radiosensitivity of oesophageal carcinoma via the PI3K/Akt signaling pathway.

    Science.gov (United States)

    Yang, Xing-Xiao; Ma, Ming; Sang, Mei-Xiang; Zhang, Xue-Yuan; Liu, Zhi-Kun; Song, Heng; Zhu, Shu-Chai

    2018-02-01

    BMI-1 knockdown, while the kinase agonist IGF-1 reversed the effects of BMI-1 knockdown on cell viability and radiosensitivity. Taken together, BMI-1 knockdown induces radiosensitivity in ESCC and significantly inhibits cell viability, which may contribute to an increased proportion of cells in the G0/G1 phase and cell apoptosis via suppression of the PI3K/Akt signalling pathway.

  4. Glycine enhances muscle protein mass associated with maintaining Akt-mTOR-FOXO1 signaling and suppressing TLR4 and NOD2 signaling in piglets challenged with LPS.

    Science.gov (United States)

    Liu, Yulan; Wang, Xiuying; Wu, Huanting; Chen, Shaokui; Zhu, Huiling; Zhang, Jing; Hou, Yongqing; Hu, Chien-An Andy; Zhang, Guolong

    2016-08-01

    Pro-inflammatory cytokines play a critical role in the pathophysiology of muscle atrophy. We hypothesized that glycine exerted an anti-inflammatory effect and alleviated lipopolysaccharide (LPS)-induced muscle atrophy in piglets. Pigs were assigned to four treatments including the following: 1) nonchallenged control, 2) LPS-challenged control, 3) LPS+1.0% glycine, and 4) LPS+2.0% glycine. After receiving the control, 1.0 or 2.0% glycine-supplemented diets, piglets were treated with either saline or LPS. At 4 h after treatment with saline or LPS, blood and muscle samples were harvested. We found that 1.0 or 2.0% glycine increased protein/DNA ratio, protein content, and RNA/DNA ratio in gastrocnemius or longissimus dorsi (LD) muscles. Glycine also resulted in decreased mRNA expression of muscle atrophy F-box (MAFbx) and muscle RING finger 1 (MuRF1) in gastrocnemius muscle. In addition, glycine restored the phosphorylation of Akt, mammalian target of rapamycin (mTOR), eukaryotic initiation factor 4E binding protein 1 (4E-BP1), and Forkhead Box O 1 (FOXO1) in gastrocnemius or LD muscles. Furthermore, glycine resulted in decreased plasma tumor necrosis factor-α (TNF-α) concentration and muscle TNF-α mRNA abundance. Moreover, glycine resulted in decreased mRNA expresson of Toll-like receptor 4 (TLR4), nucleotide-binding oligomerization domain protein 2 (NOD2), and their respective downstream molecules in gastrocnemius or LD muscles. These results indicate glycine enhances muscle protein mass under an inflammatory condition. The beneficial roles of glycine on the muscle are closely associated with maintaining Akt-mTOR-FOXO1 signaling and suppressing the activation of TLR4 and/or NOD2 signaling pathways. Copyright © 2016 the American Physiological Society.

  5. Salicylic acid suppresses jasmonic acid signaling downstream of SCFCOI1-JAZ by targeting GCC promoter motifs via transcription factor ORA59

    NARCIS (Netherlands)

    Does, D. van der; Leon-Reyes, A.; Koornneef, A.; Verk, M.C. van; Rodenburg, N.; Pauwels, L.; Goossens, A.; Körbes, A.P.; Memelink, J.; Ritsema, T.; Wees, S.C.M. van; Pieterse, C.M.J.

    2013-01-01

    Antagonism between the defense hormones salicylic acid (SA) and jasmonic acid (JA) plays a central role in the modulation of the plant immune signaling network, but the molecular mechanisms underlying this phenomenon are largely unknown. Here, we demonstrate that suppression of the JA pathway by SA

  6. Metformin-mediated growth inhibition involves suppression of the IGF-I receptor signalling pathway in human pancreatic cancer cells

    International Nuclear Information System (INIS)

    Karnevi, Emelie; Said, Katarzyna; Andersson, Roland; Rosendahl, Ann H

    2013-01-01

    Epidemiological studies have shown direct associations between type 2 diabetes and obesity, both conditions associated with hyperglycaemia and hyperinsulinemia, and the risk of pancreatic cancer. Up to 80% of pancreatic cancer patients present with either new-onset type 2 diabetes or impaired glucose tolerance at the time of diagnosis. Recent population studies indicate that the incidence of pancreatic cancer is reduced among diabetics taking metformin. In this study, the effects of exposure of pancreatic cancer cells to high glucose levels on their growth and response to metformin were investigated. The human pancreatic cancer cell lines AsPC-1, BxPC-3, PANC-1 and MIAPaCa-2 were grown in normal (5 mM) or high (25 mM) glucose conditions, with or without metformin. The influence by metformin on proliferation, apoptosis and the AMPK and IGF-IR signalling pathways were evaluated in vitro. Metformin significantly reduced the proliferation of pancreatic cancer cells under normal glucose conditions. Hyperglycaemia however, protected against the metformin-induced growth inhibition. The anti-proliferative actions of metformin were associated with an activation of AMP-activated protein kinase AMPK Thr172 together with an inhibition of the insulin/insulin-like growth factor-I (IGF-I) receptor activation and downstream signalling mediators IRS-1 and phosphorylated Akt. Furthermore, exposure to metformin during normal glucose conditions led to increased apoptosis as measured by poly(ADP-ribose) polymerase (PARP) cleavage. In contrast, exposure to high glucose levels promoted a more robust IGF-I response and Akt activation which correlated to stimulated AMPK Ser485 phosphorylation and impaired AMPK Thr172 phosphorylation, resulting in reduced anti-proliferative and apoptotic effects by metformin. Our results indicate that metformin has direct anti-tumour activities in pancreatic cancer cells involving AMPK Thr172 activation and suppression of the insulin/IGF signalling pathways

  7. Elevated CO2 reduces the resistance and tolerance of tomato plants to Helicoverpa armigera by suppressing the JA signaling pathway.

    Directory of Open Access Journals (Sweden)

    Huijuan Guo

    Full Text Available Both resistance and tolerance, which are two strategies that plants use to limit biotic stress, are affected by the abiotic environment including atmospheric CO(2 levels. We tested the hypothesis that elevated CO(2 would reduce resistance (i.e., the ability to prevent damage but enhance tolerance (i.e., the ability to regrow and compensate for damage after the damage has occurred of tomato plants to the cotton bollworm, Helicoverpa armigera. The results showed that elevated CO(2 reduced resistance by decreasing the jasmonic acid (JA level and activities of lipoxygenase, proteinase inhibitors, and polyphenol oxidase in wild-type (WT plants infested with H. armigera. Consequently, the activities of total protease, trypsin-like enzymes, and weak and active alkaline trypsin-like enzymes increased in the midgut of H. armigera when fed on WT plants grown under elevated CO(2. Unexpectedly, the tolerance of the WT to H. armigera (in terms of photosynthetic rate, activity of sucrose phosphate synthases, flower number, and plant biomass and height was also reduced by elevated CO(2. Under ambient CO(2, the expression of resistance and tolerance to H. armigera was much greater in wild type than in spr2 (a JA-deficient genotype plants, but elevated CO(2 reduced these differences of the resistance and tolerance between WT and spr2 plants. The results suggest that the JA signaling pathway contributes to both plant resistance and tolerance to herbivorous insects and that by suppressing the JA signaling pathway, elevated CO(2 will simultaneously reduce the resistance and tolerance of tomato plants.

  8. Syndecan-1-dependent suppression of PDK1/Akt/bad signaling by docosahexaenoic acid induces apoptosis in prostate cancer.

    Science.gov (United States)

    Hu, Yunping; Sun, Haiguo; Owens, Rick T; Gu, Zhennan; Wu, Jansheng; Chen, Yong Q; O'Flaherty, Joseph T; Edwards, Iris J

    2010-10-01

    Evidence indicates that diets enriched in n-3 polyunsaturated fatty acids (n-3 PUFAs) reduce the risk of prostate cancer, but biochemical mechanisms are unclear. Syndecan-1 (SDC-1), a transmembrane heparan sulfate proteoglycan, supports the integrity of the epithelial compartment. In tumor cells of epithelial lineage, SDC-1 is generally downregulated. This may result in perturbation of homeostasis and lead to progression of malignancy. Our studies have shown that the n-3 PUFA species, docosahexaenoic acid (DHA), increases SDC-1 expression in prostate tissues of Pten knockout (Pten(P-/-)) mice/cells and human prostate cancer cells. We have now determined that DHA-mediated up-regulation of SDC-1 induces apoptosis. Bovine serum albumin-bound DHA and exogenous human recombinant SDC-1 ecotodomain were delivered to PC3 and LNCaP cells in the presence or absence of SDC-1 small interfering (si)RNA. In the presence of control siRNA, both DHA and SDC-1 ectodomain induced apoptosis, whereas SDC-1 silencing blocked DHA-induced but not SDC-1 ectodomain-induced apoptosis. Downstream effectors of SDC-1 signaling linked to n-3 PUFA-induced apoptosis involved the 3'-phosphoinositide-dependent kinase 1 (PDK1)/Akt/Bad integrating network. A diet enriched in n-3 PUFA decreased phosphorylation of PDK1, Akt (T308), and Bad in prostates of Pten(P-/-) mice. Similar results were observed in human prostate cancer cells in response to DHA and SDC-1 ectodomain. The effect of DHA on PDK1/Akt/Bad signaling was abrogated by SDC-1 siRNA. These findings define a mechanism by which SDC-1-dependent suppression of phosphorylation of PDK1/Akt/Bad mediates n-3 PUFA-induced apoptosis in prostate cancer.

  9. PARP-1 modulation of mTOR signaling in response to a DNA alkylating agent.

    Directory of Open Access Journals (Sweden)

    Chantal Ethier

    Full Text Available Poly(ADP-ribose polymerase-1 (PARP-1 is widely involved in cell death responses. Depending on the degree of injury and on cell type, PARP activation may lead to autophagy, apoptosis or necrosis. In HEK293 cells exposed to the alkylating agent N-methyl-N'-nitro-N'-nitrosoguanine (MNNG, we show that PARP-1 activation triggers a necrotic cell death response. The massive poly(ADP-ribose (PAR synthesis following PARP-1 activation leads to the modulation of mTORC1 pathway. Shortly after MNNG exposure, NAD⁺ and ATP levels decrease, while AMP levels drastically increase. We characterized at the molecular level the consequences of these altered nucleotide levels. First, AMP-activated protein kinase (AMPK is activated and the mTORC1 pathway is inhibited by the phosphorylation of Raptor, in an attempt to preserve cellular energy. Phosphorylation of the mTORC1 target S6 is decreased as well as the phosphorylation of the mTORC2 component Rictor on Thr1135. Finally, Akt phosphorylation on Ser473 is lost and then, cell death by necrosis occurs. Inhibition of PARP-1 with the potent PARP inhibitor AG14361 prevents all of these events. Moreover, the antioxidant N-acetyl-L-cysteine (NAC can also abrogate all the signaling events caused by MNNG exposure suggesting that reactive oxygen species (ROS production is involved in PARP-1 activation and modulation of mTOR signaling. In this study, we show that PARP-1 activation and PAR synthesis affect the energetic status of cells, inhibit the mTORC1 signaling pathway and possibly modulate the mTORC2 complex affecting cell fate. These results provide new evidence that cell death by necrosis is orchestrated by the balance between several signaling pathways, and that PARP-1 and PAR take part in these events.

  10. Astaxanthin Suppresses MPP+-Induced Oxidative Damage in PC12 Cells through a Sp1/NR1 Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Xiaochun Chen

    2013-03-01

    Full Text Available Objective: To investigate astaxanthin (ATX neuroprotection, and its mechanism, on a 1-methyl-4-phenyl-pyridine ion (MPP+-induced cell model of Parkinson’s disease. Methods: Mature, differentiated PC12 cells treated with MPP+ were used as an in vitro cell model. The MTT assay was used to investigate cell viability after ATX treatment, and western blot analysis was used to observe Sp1 (activated transcription factor 1 and NR1 (NMDA receptor subunit 1 protein expression, real-time PCR was used to monitor Sp1 and NR1 mRNA, and cell immunofluorescence was used to determine the location of Sp1 and NR1 protein and the nuclear translocation of Sp1. Results: PC12 cell viability was significantly reduced by MPP+ treatment. The expression of Sp1 and NR1 mRNA and protein were increased compared with the control (p < 0.01. Following co-treatment with ATX and MPP+, cell viability was significantly increased, and Sp1 and NR1 mRNA and protein were decreased, compared with the MPP+ groups (p < 0.01. In addition, mithracycin A protected PC12 cells from oxidative stress caused by MPP+ by specifically inhibiting the expression of Sp1. Moreover, cell immunofluorescence revealed that ATX could suppress Sp1 nuclear transfer. Conclusion: ATX inhibited oxidative stress induced by MPP+ in PC12 cells, via the SP1/NR1 signaling pathway.

  11. Blocking gp130 signaling suppresses autotaxin expression in adipocytes and improves insulin sensitivity in diet-induced obesity.

    Science.gov (United States)

    Sun, Shuhong; Wang, Ran; Song, Jianwen; Guan, Ming; Li, Na; Zhang, Xiaotian; Zhao, Zhenwen; Zhang, Junjie

    2017-11-01

    Autotaxin (ATX), which is highly expressed and secreted by adipocytes, functions as the key enzyme to generate lysophosphatidic acid (LPA) from lysophosphatidylcholine. Adipose tissue is the main source of circulating ATX that modulates plasma LPA levels. Upregulation of ATX expression in obese patients and mice is closely related with insulin resistance and impaired glucose tolerance. However, the mechanism of ATX expression in adipocytes remains largely unknown. In this study, we found that glycoprotein 130 (gp130)-mediated Janus kinase (JAK)-signal transducer and activator of transcription 3 (STAT3) activation was required for abundant ATX expression in adipocytes. Through gp130, the interleukin 6 (IL-6) family cytokines, such as IL-6, leukemia inhibitory factor, cardiotrophin-1, and ciliary neurotrophic factor, upregulated ATX expression in adipocytes. ATX contributes to the induction of insulin resistance and lipolysis in IL-6-stimulated adipocytes. Oral administration of gp130 inhibitor SC144 suppressed ATX expression in adipose tissue, decreased plasma ATX, LPA, and FFA levels, and significantly improved insulin sensitivity and glucose tolerance in high-fat diet-fed obese mice. In summary, our results indicate that the activation of gp130-JAK-STAT3 pathway by IL-6 family cytokines has an important role in regulating ATX expression in adipocytes and that gp130 is a promising target in the management of obesity-associated glucose metabolic diseases. Copyright © 2017 by the American Society for Biochemistry and Molecular Biology, Inc.

  12. IFNγ-induced suppression of β-catenin signaling: evidence for roles of Akt and 14.3.3ζ

    Science.gov (United States)

    Nava, Porfirio; Kamekura, Ryuta; Quirós, Miguel; Medina-Contreras, Oscar; Hamilton, Ross W.; Kolegraff, Keli N.; Koch, Stefan; Candelario, Aurora; Romo-Parra, Hector; Laur, Oskar; Hilgarth, Roland S.; Denning, Timothy L.; Parkos, Charles A.; Nusrat, Asma

    2014-01-01

    The proinflammatory cytokine interferon γ (IFNγ ) influences intestinal epithelial cell (IEC) homeostasis in a biphasic manner by acutely stimulating proliferation that is followed by sustained inhibition of proliferation despite continued mucosal injury. β-Catenin activation has been classically associated with increased IEC proliferation. However, we observed that IFNγ inhibits IEC proliferation despite sustained activation of Akt/β-catenin signaling. Here we show that inhibition of Akt/β-catenin–mediated cell proliferation by IFNγ is associated with the formation of a protein complex containing phosphorylated β-catenin 552 (pβ-cat552) and 14.3.3ζ. Akt1 served as a bimodal switch that promotes or inhibits β-catenin transactivation in response to IFNγ stimulation. IFNγ initially promotes β-catenin transactivation through Akt-dependent C-terminal phosphorylation of β-catenin to promote its association with 14.3.3ζ. Augmented β-catenin transactivation leads to increased Akt1 protein levels, and active Akt1 accumulates in the nucleus, where it phosphorylates 14.3.3ζ to translocate 14.3.3ζ/β-catenin from the nucleus, thereby inhibiting β-catenin transactivation and IEC proliferation. These results outline a dual function of Akt1 that suppresses IEC proliferation during intestinal inflammation. PMID:25079689

  13. Cxcr2 signaling and the microbiome suppress inflammation, bile duct injury, and the phenotype of experimental biliary atresia

    Science.gov (United States)

    Jee, Junbae; Mourya, Reena; Shivakumar, Pranavkumar; Fei, Lin; Wagner, Michael

    2017-01-01

    Biliary atresia is progressive fibro-inflammatory cholangiopathy of young children. Central to pathogenic mechanisms of injury is the tissue targeting by the innate and adaptive immune cells. Among these cells, neutrophils and the IL-8/Cxcl-8 signaling via its Cxcr2 receptor have been linked to bile duct injury. Here, we aimed to investigate whether the intestinal microbiome modulates Cxcr2-dependent bile duct injury and obstruction. Adult wild-type (WT) and Cxcr2-/- mice were fed a diet supplemented with sulfamethoxazole/trimethoprim (SMZ/TMP) during pregnancy and lactation, and their pups were injected intraperitoneally with rhesus rotavirus (RRV) within 24 hours of life to induce experimental biliary atresia. The maternal exposure to SMZ/TMP significantly lowered the incidence of jaundice and bile duct obstruction and resulted in improved survival, especially in Cxcr2-/- mice. Analyses of the microbiome by deep sequencing of 16S rRNA of the neonatal colon showed a delay in bacterial colonization of WT mice induced by SMZ/TMP, with a notable switch from Proteobacteria to Firmicutes. Interestingly, the genetic inactivation of Cxcr2 alone produced a similar bacterial shift. When treated with SMZ/TMP, Cxcr2-/- mice infected with RRV to induce experimental biliary atresia showed further enrichment of Corynebacterium, Anaerococcus and Streptococcus. Among these, Anaerococcus lactolyticus was significantly associated with a suppression of biliary injury, cholestasis, and survivability. These results suggest that the postnatal development of the intestinal microbiota is an important susceptibility factor for experimental biliary atresia. PMID:28763485

  14. Stanniocalicin 2 suppresses breast cancer cell migration and invasion via the PKC/claudin-1-mediated signaling.

    Directory of Open Access Journals (Sweden)

    Jing Hou

    Full Text Available Stanniocalcin (STC, a glycoprotein hormone, is expressed in a wide variety of tissues to regulate Ca2+ and PO4- homeostasis. STC2, a member of STC family, has been reported to be associated with tumor development. In this study, we investigated whether the expression of STC2 is associated with migration and invasion of breast cancer cells. We found that breast cancer cell line 231 HM transfected with STC2 shRNA displayed high motility, fibroblast morphology, and enhanced cell migration and invasion. Introduction of STC2 in 231 cells reduced cell migration and invasion. In response to irradiation, silencing of STC2 in 231 HM cells reduced apoptosis, whereas overexpression of STC2 in 231 cells promoted apoptosis, compared with in control cells. Mechanistic study showed that STC2 negatively regulated PKC to control the expression of Claudin-1, which subsequently induced the expressions of EMT-related factors including ZEB1, ZO-1, Slug, Twist, and MMP9. Suppression of PKC activity by using a PKC inhibitor (Go 6983 restored the normal motility of STC2-silenced cells. Furthermore, in vivo animal assay showed that STC2 inhibited tumorigenesis and metastasis of breast cancer cells. Collectively, these results indicate that STC2 may inhibit EMT at least partially through the PKC/Claudin-1-mediated signaling in human breast cancer cells. Thus, STC2 may be exploited as a biomarker for metastasis and targeted therapy in human breast cancer.

  15. Labor Inhibits Placental Mechanistic Target of Rapamycin Complex 1 Signaling

    Science.gov (United States)

    LAGER, Susanne; AYE, Irving L.M.H.; GACCIOLI, Francesca; RAMIREZ, Vanessa I.; JANSSON, Thomas; POWELL, Theresa L.

    2014-01-01

    Introduction Labor induces a myriad of changes in placental gene expression. These changes may represent a physiological adaptation inhibiting placental cellular processes associated with a high demand for oxygen and energy (e.g., protein synthesis and active transport) thereby promoting oxygen and glucose transfer to the fetus. We hypothesized that mechanistic target of rapamycin complex 1 (mTORC1) signaling, a positive regulator of trophoblast protein synthesis and amino acid transport, is inhibited by labor. Methods Placental tissue was collected from healthy, term pregnancies (n=15 no-labor; n=12 labor). Activation of Caspase-1, IRS1/Akt, STAT, mTOR, and inflammatory signaling pathways was determined by Western blot. NFκB p65 and PPARγ DNA binding activity was measured in isolated nuclei. Results Labor increased Caspase-1 activation and mTOR complex 2 signaling, as measured by phosphorylation of Akt (S473). However, mTORC1 signaling was inhibited in response to labor as evidenced by decreased phosphorylation of mTOR (S2448) and 4EBP1 (T37/46 and T70). Labor also decreased NFκB and PPARγ DNA binding activity, while having no effect on IRS1 or STAT signaling pathway. Discussion and conclusion Several placental signaling pathways are affected by labor, which has implications for experimental design in studies of placental signaling. Inhibition of placental mTORC1 signaling in response to labor may serve to down-regulate protein synthesis and amino acid transport, processes that account for a large share of placental oxygen and glucose consumption. We speculate that this response preserves glucose and oxygen for transfer to the fetus during the stressful events of labor. PMID:25454472

  16. Puerarin suppresses proliferation of endometriotic stromal cells partly via the MAPK signaling pathway induced by 17ß-estradiol-BSA.

    Directory of Open Access Journals (Sweden)

    Wen Cheng

    Full Text Available BACKGROUND: Puerarin is a major isoflavonoid compound extracted from Radix puerariae. It has a weak estrogenic action by binding to estrogen receptors (ERs. In our early clinical practice to treat endometriosis, a better therapeutic effect was achieved if the formula of traditional Chinese medicine included Radix puerariae. The genomic and non-genomic effects of puerarin were studied in our Lab. This study aims to investigate the ability of puerarin to bind competitively to ERs in human endometriotic stromal cells (ESCs, determine whether and how puerarin may influence phosphorylation of the non-genomic signaling pathway induced by 17ß-estradiol conjugated to BSA (E(2-BSA. METHODOLOGY: ESCs were successfully established. Binding of puerarin to ERs was assessed by a radioactive competitive binding assay in ESCs. Activation of the signaling pathway was screened by human phospho-kinase array, and was further confirmed by western blot. Cell proliferation was analyzed according to the protocol of CCK-8. The mRNA and protein levels of cyclin D1, Cox-2 and Cyp19 were determined by real-time PCR and western blotting. Inhibitor of MEK1/2 or ER antagonist was used to confirm the involved signal pathway. PRINCIPAL FINDINGS: Our data demonstrated that the total binding ability of puerarin to ERs on viable cells is around 1/3 that of 17ß-estradiol (E(2. E(2-BSA was able to trigger a rapid, non-genomic, membrane-mediated activation of ERK1/2 in ESCs and this phenomenon was associated with an increased proliferation of ESCs. Treating ESCs with puerarin abrogated the phosphorylation of ERK and significantly decreased cell proliferation, as well as related gene expression levels enhanced by E(2-BSA. CONCLUSIONS/SIGNIFICANCE: Puerarin suppresses proliferation of ESCs induced by E(2-BSA partly via impeding a rapid, non-genomic, membrane-initiated ERK pathway, and down-regulation of Cyclin D1, Cox-2 and Cyp19 are involved in the process. Our data further show

  17. AC-93253 iodide, a novel Src inhibitor, suppresses NSCLC progression by modulating multiple Src-related signaling pathways.

    Science.gov (United States)

    Lai, Yi-Hua; Lin, Sih-Yin; Wu, Yu-Shan; Chen, Huei-Wen; Chen, Jeremy J W

    2017-11-13

    The tyrosine kinase Src is involved in the progression of many cancers. Moreover, inhibiting Src activity has been shown to obstruct several signaling pathways regulated by the EGFR. Thus, Src is a valuable target molecule in drug development. The purpose of this study was to identify compounds that directly or indirectly modulate Src to suppress lung cancer cell growth and motility and to investigate the molecular mechanisms underlying the effects of these compounds. Human non-small cell lung cancer (NSCLC) cell lines (PC9, PC9/gef, A549, and H1975) with different EGFR statuses were tested by cytotoxicity and proliferation assays after AC-93253 iodide treatment. Src and Src-related protein expression in AC-93253 iodide-treated PC9, PC9/gef, and A549 cells were assessed by western blotting. The effects of AC-93253 iodide on cancer cell colony formation, invasion, and migration were assessed in PC9 and PC9/gef cells. The synergistic effects of gefitinib and AC-93253 iodide were evaluated by combination index (CI)-isobologram analysis in gefitinib-resistant cell lines. The efficacy of AC-93253 iodide in vivo was determined using nude mice treated with either the compound or the vehicle. Among the compounds, AC-93253 iodide exhibited the most potent dose-independent inhibitory effects on the activity of Src as well as on that of the Src-related proteins EGFR, STAT3, and FAK. Furthermore, AC-93253 iodide significantly suppressed cancer cell proliferation, colony formation, invasion, and migration in vitro and tumor growth in vivo. AC-93253 iodide sensitized tumor cells to gefitinib treatment regardless of whether the cells were gefitinib-sensitive (PC9) or resistant (H1975 and PC9/gef), indicating that it may exert synergistic effects when used in combination with established therapeutic agents. Our findings also suggested that the inhibitory effects of AC-93253 iodide on lung cancer progression may be attributable to its ability to modulate multiple proteins

  18. A Multi-Lineage Screen Reveals mTORC1 Inhibition Enhances Human Pluripotent Stem Cell Mesendoderm and Blood Progenitor Production

    Directory of Open Access Journals (Sweden)

    Emanuel Joseph Paul Nazareth

    2016-05-01

    Full Text Available Human pluripotent stem cells (hPSCs exist in heterogeneous micro-environments with multiple subpopulations, convoluting fate-regulation analysis. We patterned hPSCs into engineered micro-environments and screened responses to 400 small-molecule kinase inhibitors, measuring yield and purity outputs of undifferentiated, neuroectoderm, mesendoderm, and extra-embryonic populations. Enrichment analysis revealed mammalian target of rapamycin (mTOR inhibition as a strong inducer of mesendoderm. Dose responses of mTOR inhibitors such as rapamycin synergized with Bone Morphogenetic protein 4 (BMP4 and activin A to enhance the yield and purity of BRACHYURY-expressing cells. Mechanistically, small interfering RNA knockdown of RAPTOR, a component of mTOR complex 1, phenocopied the mesendoderm-enhancing effects of rapamycin. Functional analysis during mesoderm and endoderm differentiation revealed that mTOR inhibition increased the output of hemogenic endothelial cells 3-fold, with a concomitant enhancement of blood colony-forming cells. These data demonstrate the power of our multi-lineage screening approach and identify mTOR signaling as a node in hPSC differentiation to mesendoderm and its derivatives.

  19. Silencing of CEMIP suppresses Wnt/β-catenin/Snail signaling transduction and inhibits EMT program of colorectal cancer cells.

    Science.gov (United States)

    Liang, Guodong; Fang, Xuedong; Yang, Yubo; Song, Yan

    2018-01-01

    Cell migration inducing hyaluronan binding protein (CEMIP) is a hyaluronic acid binding protein, the abnormal elevation of which is suggested as a contributor in the carcinogenesis of colorectal cancer (CRC). Cancer cells lose their adhesive properties and acquire an enhanced mobility by undergoing epithelial-mesenchymal transition (EMT). This study is performed to investigate whether and how CEMIP orchestrates the EMT process of CRC cells. To avoid the unexpected off-target effects possibly caused by one single shRNA, two shRNAs targeting different mRNA regions of CEMIP gene were used to knock down the mRNA and protein expression of CEMIP. Our data showed that the proliferation, migration and invasion of two CRC cell lines, HCT116 and SW480 cells, were inhibited by CEMIP shRNA. We here defined EMT as the complete or partial loss of E-cadherin and zona occludens protein 1 (ZO-1) (epithelial markers) and the gain of Vimentin and N-cadherin (mesenchymal markers), and found that the EMT process was attenuated in CEMIP-silenced SW480 cells. Snail, a direct target of β-catenin/T cell factor complex, is known to activate the EMT program during cancer metastasis. CEMIP shRNA was further found to suppress the Wnt/β-catenin/Snail signaling transduction in CRC cells as manifested by the decreased nuclear β-catenin and Snail. Collectively, our work demonstrates that CEMIP contributes to metastatic phenotype of CRC cells in vitro. Copyright © 2017 Elsevier GmbH. All rights reserved.

  20. NLRP3 and ASC suppress lupus-like autoimmunity by driving the immunosuppressive effects of TGF-β receptor signalling.

    Science.gov (United States)

    Lech, Maciej; Lorenz, Georg; Kulkarni, Onkar P; Grosser, Marian O O; Stigrot, Nora; Darisipudi, Murthy N; Günthner, Roman; Wintergerst, Maximilian W M; Anz, David; Susanti, Heni Eka; Anders, Hans-Joachim

    2015-12-01

    The NLRP3/ASC inflammasome drives host defence and autoinflammatory disorders by activating caspase-1 to trigger the secretion of mature interleukin (IL)-1β/IL-18, but its potential role in autoimmunity is speculative. We generated and phenotyped Nlrp3-deficient, Asc-deficient, Il-1r-deficient and Il-18-deficient C57BL/6-lpr/lpr mice, the latter being a mild model of spontaneous lupus-like autoimmunity. While lack of IL-1R or IL-18 did not affect the C57BL/6-lpr/lpr phenotype, lack of NLRP3 or ASC triggered massive lymphoproliferation, lung T cell infiltrates and severe proliferative lupus nephritis within 6 months, which were all absent in age-matched C57BL/6-lpr/lpr controls. Lack of NLRP3 or ASC increased dendritic cell and macrophage activation, the expression of numerous proinflammatory mediators, lymphocyte necrosis and the expansion of most T cell and B cell subsets. In contrast, plasma cells and autoantibody production were hardly affected. This unexpected immunosuppressive effect of NLRP3 and ASC may relate to their known role in SMAD2/3 phosphorylation during tumour growth factor (TGF)-β receptor signalling, for example, Nlrp3-deficiency and Asc-deficiency significantly suppressed the expression of numerous TGF-β target genes in C57BL/6-lpr/lpr mice and partially recapitulated the known autoimmune phenotype of Tgf-β1-deficient mice. These data identify a novel non-canonical immunoregulatory function of NLRP3 and ASC in autoimmunity. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  1. Ursolic acid simultaneously targets multiple signaling pathways to suppress proliferation and induce apoptosis in colon cancer cells.

    Directory of Open Access Journals (Sweden)

    Jingshu Wang

    Full Text Available Ursolic acid (UA, a natural pentacyclic triterpenoid carboxylic acid distributed in medical herbs, exerts antitumor effects and is emerging as a promising compound for cancer prevention and therapy, but its excise mechanisms of action in colon cancer cells remains largely unknown. Here, we identified the molecular mechanisms by which UA inhibited cell proliferation and induced apoptosis in human colon cancer SW480 and LoVo cells. Treatment with UA led to significant inhibitions in cell viability and clone formation and changes in cell morphology and spreading. UA also suppressed colon cancer cell migration by inhibiting MMP9 and upregulating CDH1 expression. Further studies showed that UA inhibited the phosphorylation of Akt and ERK proteins. Pretreatment with an Akt or ERK-specific inhibitor considerably abrogated the proliferation inhibition by UA. UA also significantly inhibited colon cancer cell COX-2 expression and PGE2 production. Pretreatment with a COX-2 inhibitor (celecoxib abrogated the UA-induced cell proliferation. Moreover, we found that UA effectively promoted NF-κB and p300 translocation from cell nuclei to cytoplasm, and attenuated the p300-mediated acetylation of NF-κB and CREB2. Pretreatment with a p300 inhibitor (roscovitine abrogated the UA-induced cell proliferation, which is reversed by p300 overexpression. Furthermore, UA treatment induced colon cancer cell apoptosis, increased the cleavage of PARP, caspase-3 and 9, and trigged the release of cytochrome c from mitochondrial inter-membrane space into cytosol. These results indicate that UA inhibits cell proliferation and induces apoptosis in colon cancer cells through simultaneous modulation of the multiple signaling pathways such as MMP9/CDH1, Akt/ERK, COX-2/PGE2, p300/NF-κB/CREB2, and cytochrome c/caspase pathways.

  2. Suppression of PTEN/AKT signaling decreases the expression of TUBB3 and TOP2A with subsequent inhibition of cell growth and induction of apoptosis in human breast cancer MCF-7 cells via ATP and caspase-3 signaling pathways.

    Science.gov (United States)

    Yang, Zhenhua; Liu, Ying; Shi, Changzheng; Zhang, Yuqin; Lv, Rongzhao; Zhang, Rong; Wang, Qian; Wang, Yiming

    2017-02-01

    The aim of the present study was to evaluate the effects of PTEN/AKT signaling on TUBB3 and TOP2A expression and on the subsequent cell growth of human breast cancer MCF-7 cells. We found that the disease-free survival (DFS) and overall survival (OS) of breast cancer patients with TUBB3‑positive tumors were lower than these rates in the patients with TUBB3-negative tumors. Meanwhile, DFS and OS of breast cancer patients with TOP2A-positive tumors were also lower than these rates in patients with TOP2A-negative tumors. Suppression of PTEN reduced the protein expression of TUBB3 and TOP2A in MCF-7 cells. Suppression of PTEN also reduced cell proliferation and induced apoptosis and caspase-3 activity in MCF-7 cells. Moreover, an increase in ATP also reduced TUBB3 and TOP2A protein expression, reduced cell proliferation and induced apoptosis and caspase-3 activity in the MCF-7 cells following suppression of PTEN. Suppression of phosphorylation-AKT (p-AKT) reduced the protein expression of TUBB3 and TOP2A in the MCF-7 cells. Suppression of p-AKT also reduced cell proliferation and induced apoptosis and caspase-3 activity in the MCF-7 cells. Then, ATP also reduced TUBB3 and TOP2A protein expression, reduced cell proliferation and induced apoptosis and caspase-3 activity in MCF-7 cells following suppression of p-AKT. These results suggest that PTEN/AKT signaling affects the expression of TUBB3 and TOP2A reducing cell growth and inducing apoptosis of human breast cancer MCF-7 cells through ATP and caspase-3 signaling pathways. TUBB3 and TOP2A may be promising prognostic markers for the efficacy of adjuvant cisplatin-based chemotherapy.

  3. 7-Dehydrocholesterol (7-DHC), But Not Cholesterol, Causes Suppression of Canonical TGF-β Signaling and Is Likely Involved in the Development of Atherosclerotic Cardiovascular Disease (ASCVD).

    Science.gov (United States)

    Huang, Shuan Shian; Liu, I-Hua; Chen, Chun-Lin; Chang, Jia-Ming; Johnson, Frank E; Huang, Jung San

    2017-06-01

    For several decades, cholesterol has been thought to cause ASCVD. Limiting dietary cholesterol intake has been recommended to reduce the risk of the disease. However, several recent epidemiological studies do not support a relationship between dietary cholesterol and/or blood cholesterol and ASCVD. Consequently, the role of cholesterol in atherogenesis is now uncertain. Much evidence indicates that TGF-β, an anti-inflammatory cytokine, protects against ASCVD and that suppression of canonical TGF-β signaling (Smad2-dependent) is involved in atherogenesis. We had hypothesized that cholesterol causes ASCVD by suppressing canonical TGF-β signaling in vascular endothelium. To test this hypothesis, we determine the effects of cholesterol, 7-dehydrocholesterol (7-DHC; the biosynthetic precursor of cholesterol), and other sterols on canonical TGF-β signaling. We use Mv1Lu cells (a model cell system for studying TGF-β activity) stably expressing the Smad2-dependent luciferase reporter gene. We demonstrate that 7-DHC (but not cholesterol or other sterols) effectively suppresses the TGF-β-stimulated luciferase activity. We also demonstrate that 7-DHC suppresses TGF-β-stimulated luciferase activity by promoting lipid raft/caveolae formation and subsequently recruiting cell-surface TGF-β receptors from non-lipid raft microdomains to lipid rafts/caveolae where TGF-β receptors become inactive in transducing canonical signaling and undergo rapid degradation upon TGF-β binding. We determine this by cell-surface 125 I-TGF-β-cross-linking and sucrose density gradient ultracentrifugation. We further demonstrate that methyl-β-cyclodextrin (MβCD), a sterol-chelating agent, reverses 7-DHC-induced suppression of TGF-β-stimulated luciferase activity by extrusion of 7-DHC from resident lipid rafts/caveolae. These results suggest that 7-DHC, but not cholesterol, promotes lipid raft/caveolae formation, leading to suppression of canonical TGF-β signaling and atherogenesis. J

  4. Delphinidin, a specific inhibitor of histone acetyltransferase, suppresses inflammatory signaling via prevention of NF-κB acetylation in fibroblast-like synoviocyte MH7A cells

    International Nuclear Information System (INIS)

    Seong, Ah-Reum; Yoo, Jung-Yoon; Choi, KyungChul; Lee, Mee-Hee; Lee, Yoo-Hyun; Lee, Jeongmin; Jun, Woojin; Kim, Sunoh; Yoon, Ho-Geun

    2011-01-01

    Highlights: → Delphinidin is a novel inhibitor of p300/CBP histone acetyltransferase. → Delphinidin prevents the hyperacetylation of p65 by inhibiting the HAT activity of p300/CBP. → Delphinidin efficiently suppresses the expression of inflammatory cytokines in MH7A cells via hypoacetylation of NF-κB. → Delphinidin inhibits cytokine release in the Jurkat T lymphocyte cell line. -- Abstract: Histone acetyltransferase (HAT) inhibitors (HATi) isolated from dietary compounds have been shown to suppress inflammatory signaling, which contributes to rheumatoid arthritis. Here, we identified a novel HATi in Punica granatum L. known as delphinidin (DP). DP did not affect the activity of other epigenetic enzymes (histone deacetylase, histone methyltransferase, or sirtuin1). DP specifically inhibited the HAT activities of p300/CBP. It also inhibited p65 acetylation in MH7A cells, a human rheumatoid arthritis synovial cell line. DP-induced hypoacetylation was accompanied by cytosolic accumulation of p65 and nuclear localization of IKBα. Accordingly, DP treatment inhibited TNFα-stimulated increases in NF-κB function and expression of NF-κB target genes in these cells. Importantly, DP suppressed lipopolysaccharide-induced pro-inflammatory cytokine expression in Jurkat T lymphocytes, demonstrating that HATi efficiently suppresses cytokine-mediated immune responses. Together, these results show that the HATi activity of DP counters anti-inflammatory signaling by blocking p65 acetylation and that this compound may be useful in preventing inflammatory arthritis.

  5. Delphinidin, a specific inhibitor of histone acetyltransferase, suppresses inflammatory signaling via prevention of NF-{kappa}B acetylation in fibroblast-like synoviocyte MH7A cells

    Energy Technology Data Exchange (ETDEWEB)

    Seong, Ah-Reum; Yoo, Jung-Yoon; Choi, KyungChul [Department of Biochemistry and Molecular Biology, Center for Chronic Metabolic Disease Research, College of Medicine, Yonsei University, Seoul (Korea, Republic of); Lee, Mee-Hee [Department of Biochemistry and Molecular Biology, Center for Chronic Metabolic Disease Research, College of Medicine, Yonsei University, Seoul (Korea, Republic of); Brain Korea 21 Project for Medical Sciences, Yonsei University, College of Medicine, Seoul (Korea, Republic of); Lee, Yoo-Hyun [Department of Food Science and Nutrition, The University of Suwon, Kyunggi-do (Korea, Republic of); Lee, Jeongmin [Department of Medical Nutrition, Kyung Hee University, Kyunggi-do (Korea, Republic of); Jun, Woojin [Department of Food and Nutrition, Chonnam National University, Gwangju (Korea, Republic of); Kim, Sunoh, E-mail: sunoh@korea.ac.kr [Jeollanamdo Institute of Natural Resources Research, Jeonnam (Korea, Republic of); Yoon, Ho-Geun, E-mail: yhgeun@yuhs.ac [Department of Biochemistry and Molecular Biology, Center for Chronic Metabolic Disease Research, College of Medicine, Yonsei University, Seoul (Korea, Republic of); Brain Korea 21 Project for Medical Sciences, Yonsei University, College of Medicine, Seoul (Korea, Republic of)

    2011-07-08

    Highlights: {yields} Delphinidin is a novel inhibitor of p300/CBP histone acetyltransferase. {yields} Delphinidin prevents the hyperacetylation of p65 by inhibiting the HAT activity of p300/CBP. {yields} Delphinidin efficiently suppresses the expression of inflammatory cytokines in MH7A cells via hypoacetylation of NF-{kappa}B. {yields} Delphinidin inhibits cytokine release in the Jurkat T lymphocyte cell line. -- Abstract: Histone acetyltransferase (HAT) inhibitors (HATi) isolated from dietary compounds have been shown to suppress inflammatory signaling, which contributes to rheumatoid arthritis. Here, we identified a novel HATi in Punica granatum L. known as delphinidin (DP). DP did not affect the activity of other epigenetic enzymes (histone deacetylase, histone methyltransferase, or sirtuin1). DP specifically inhibited the HAT activities of p300/CBP. It also inhibited p65 acetylation in MH7A cells, a human rheumatoid arthritis synovial cell line. DP-induced hypoacetylation was accompanied by cytosolic accumulation of p65 and nuclear localization of IKB{alpha}. Accordingly, DP treatment inhibited TNF{alpha}-stimulated increases in NF-{kappa}B function and expression of NF-{kappa}B target genes in these cells. Importantly, DP suppressed lipopolysaccharide-induced pro-inflammatory cytokine expression in Jurkat T lymphocytes, demonstrating that HATi efficiently suppresses cytokine-mediated immune responses. Together, these results show that the HATi activity of DP counters anti-inflammatory signaling by blocking p65 acetylation and that this compound may be useful in preventing inflammatory arthritis.

  6. Beta2-adrenergic receptor signaling in CD4+ Foxp3+ regulatory T cells enhances their suppressive function in a PKA-dependent manner.

    Science.gov (United States)

    Guereschi, Marcia G; Araujo, Leandro P; Maricato, Juliana T; Takenaka, Maisa C; Nascimento, Vanessa M; Vivanco, Bruno C; Reis, Vanessa O; Keller, Alexandre C; Brum, Patrícia C; Basso, Alexandre S

    2013-04-01

    Beta2-adrenergic receptor (B2AR) signaling is known to impair Th1-cell differentiation and function in a cAMP-dependent way, leading to inhibition of cell proliferation and decreased production of IL-2 and IFN-γ. CD4(+) Foxp3(+) Treg cells play a key role in the regulation of immune responses and are essential for maintenance of self-tolerance. Nevertheless, very little is known about adrenergic receptor expression in Treg cells or the influence of noradrenaline on their function. Here we show that Foxp3(+) Treg cells express functional B2AR. B2AR activation in Treg cells leads to increased intracellular cAMP levels and to protein kinase A (PKA)-dependent CREB phosphorylation. We also found that signaling via B2AR enhances the in vitro suppressive activity of Treg cells. B2AR-mediated increase in Treg-cell suppressive function was associated with decreased IL-2 mRNA levels in responder CD4(+) T cells and improved Treg-cell-induced conversion of CD4(+) Foxp3(-) cells into Foxp3(+) induced Treg cells. Moreover, B2AR signaling increased CTLA-4 expression in Treg cells in a PKA-dependent way. Finally, we found that PKA inhibition totally prevented the B2AR-mediated increase in Treg-cell suppressive function. Our data suggest that sympathetic fibers are able to regulate Treg-cell suppressive activity in a positive manner through B2AR signaling. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Minocycline suppresses interleukine-6, its receptor system and signaling pathways and impairs migration, invasion and adhesion capacity of ovarian cancer cells: in vitro and in vivo studies.

    Directory of Open Access Journals (Sweden)

    Parvin Ataie-Kachoie

    Full Text Available Interleukin (IL-6 has been shown to be a major contributing factor in growth and progression of ovarian cancer. The cytokine exerts pro-tumorigenic activity through activation of several signaling pathways in particular signal transducer and activator of transcription (STAT3 and extracellular signal-regulated kinase (ERK1/2. Hence, targeting IL-6 is becoming increasingly attractive as a treatment option in ovarian cancer. Here, we investigated the effects of minocycline on IL-6 and its signaling pathways in ovarian cancer. In vitro, minocycline was found to significantly suppress both constitutive and IL-1β or 4-hydroxyestradiol (4-OH-E2-stimulated IL-6 expression in human ovarian cancer cells; OVCAR-3, SKOV-3 and CAOV-3. Moreover, minocycline down-regulated two major components of IL-6 receptor system (IL-6Rα and gp130 and blocked the activation of STAT3 and ERK1/2 pathways leading to suppression of the downstream product MCL-1. In female nude mice bearing intraperitoneal OVCAR-3 tumors, acute administration (4 and 24 h of minocycline (30 mg/kg led to suppression of IL-6. Even single dose of minocycline was effective at significantly lowering plasma and tumor IL-6 levels. In line with this, tumoral expression of p-STAT3, p-ERK1/2 and MCL-1 were decreased in minocycline-treated mice. Evaluation of the functional implication of minocycline on metastatic activity revealed the capacity of minocycline to inhibit cellular migration, invasion and adhesion associated with down-regulation of matrix metalloproteinases (MMP-2 and 9. Thus, the data suggest a potential role for minocycline in suppressing IL-6 expression and activity. These effects may prove to be an important attribute to the upcoming clinical trials of minocycline in ovarian cancer.

  8. Matrine suppresses airway inflammation by downregulating SOCS3 expression via inhibition of NF-κB signaling in airway epithelial cells and asthmatic mice

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Daqing [Department of Respiration, Xi’an Children’s Hospital, Xi’an 710003 (China); Wang, Jing [Department of Neonatology, Xi’an Children’s Hospital, Xi’an 710003 (China); Yang, Niandi [Outpatient Department, School of Aerospace Engineering, Air Force Engineering University, Xi’an 710038 (China); Ma, Haixin, E-mail: drhaixinma@163.com [Department of Quality Control, Xi’an Children’s Hospital, Xi’an 710003 (China)

    2016-08-12

    Matrine has been demonstrated to attenuate allergic airway inflammation. Elevated suppressor of cytokine signaling 3 (SOCS3) was correlated with the severity of asthma. The aim of this study was to investigate the effect of matrine on SOCS3 expression in airway inflammation. In this study, we found that matrine significantly inhibited OVA-induced AHR, inflammatory cell infiltration, goblet cell differentiation, and mucous production in a dose-dependent manner in mice. Matrine also abrogated the level of interleukin (IL)-4 and IL-13, but enhanced interferon (IFN)-γ expression, both in BALF and in lung homogenates. Furthermore, matrine impeded TNF-α-induced the expression of IL-6 and adhesion molecules in airway epithelial cells (BEAS-2B and MLE-12). Additionally, we found that matrine inhibited SOCS3 expression, both in asthmatic mice and TNF-α-stimulated epithelial cells via suppression of the NF-κB signaling pathway by using pcDNA3.1-SOCS3 plasmid, SOCS3 siRNA, or nuclear factor kappa-B (NF-κB) inhibitor PDTC. Conclusions: Matrine suppresses airway inflammation by downregulating SOCS3 expression via inhibition of NF-κB signaling in airway epithelial cells and asthmatic mice. - Highlights: • Matrine attenuates asthmatic symptoms and regulates Th1/Th2 balance in vivo. • Matrine suppresses inflammation responses in vitro. • Matrine decreases SOCS3 expression both in vivo and in vitro. • Matrine inhibits SOCS3 expression by suppressing NF-κB signaling.

  9. Suppression of Grb2 expression improved hepatic steatosis, oxidative stress, and apoptosis induced by palmitic acid in vitro partly through insulin signaling alteration.

    Science.gov (United States)

    Shan, Xiangxiang; Miao, Yufeng; Fan, Rengen; Song, Changzhi; Wu, Guangzhou; Wan, Zhengqiang; Zhu, Jian; Sun, Guan; Zha, Wenzhang; Mu, Xiangming; Zhou, Guangjun; Chen, Yan

    2013-09-01

    In this study, we aimed to study the role of growth factor receptor-bound protein 2 (Grb2) in palmitic acid-induced steatosis and other "fatty liver" symptoms in vitro. HepG2 cells, with or without stably suppressed Grb2 expression, were incubated with palmitic acid for 24 h to induce typical clinical "fatty liver" features, including steatosis, impaired glucose metabolism, oxidative stress, and apoptosis. MTT and Oil Red O assays were applied to test cell viability and fat deposition, respectively. Glucose uptake assay was used to evaluate the glucose utilization of cells. Quantitative polymerase chain reaction and Western blot were used to measure expressional changes of key markers of insulin signaling, lipid/glucose metabolism, oxidative stress, and apoptosis. After 24-h palmitic acid induction, increased fat accumulation, reduced glucose uptake, impaired insulin signaling, enhanced oxidative stress, and increased apoptosis were observed in HepG2 cells. Suppression of Grb2 in HepG2 significantly reduced fat accumulation, improved glucose metabolism, ameliorated oxidative stress, and restored the activity of insulin receptor substrate-1/Akt and MEK/ERK pathways. In addition, Grb2 deficiency attenuated hepatic apoptosis shown by reduced activation of caspase-3 and fluorescent staining. Modulation of Bcl-2 and Bak1 also contributed to reduced apoptosis. In conclusion, suppression of Grb2 expression in HepG2 cells improved hepatic steatosis, glucose metabolism, oxidative stress, and apoptosis induced by palmitic acid incubation partly though modulating the insulin signaling pathway.

  10. Curcumin inhibits urothelial tumor development by suppressing IGF2 and IGF2-mediated PI3K/AKT/mTOR signaling pathway.

    Science.gov (United States)

    Tian, Binqiang; Zhao, Yingmei; Liang, Tao; Ye, Xuxiao; Li, Zuowei; Yan, Dongliang; Fu, Qiang; Li, Yonghui

    2017-08-01

    We have previously reported that curcumin inhibits urothelial tumor development in a rat bladder carcinogenesis model. In this study, we report that curcumin inhibits urothelial tumor development by suppressing IGF2 and IGF2-mediated PI3K/AKT/mTOR signaling pathway. Curcumin inhibits IGF2 expression at the transcriptional level and decreases the phosphorylation levels of IGF1R and IRS-1 in bladder cancer cells and N-methyl-N-nitrosourea (MNU)-induced urothelial tumor tissue. Ectopic expression of IGF2 and IGF1R, but not IGF1, in bladder cancer cells restored this process, suggesting that IGF2 is a target of curcumin. Moreover, introduction of constitutively active AKT1 abolished the inhibitory effect of curcumin on cell proliferation, migration, and restored the phosphorylation levels of 4E-BP1 and S6K1, suggesting that curcumin functions via suppressing IGF2-mediated AKT/mTOR signaling pathway. In summary, our results reveal that suppressing IGF2 and IGF2-mediated PI3K/AKT/mTOR signaling pathway is one of the mechanisms of action of curcumin. Our findings suggest a new therapeutic strategy against human bladder cancer caused by aberrant activation of IGF2, which are useful for translational application of curcumin.

  11. Inositol Hexaphosphate Inhibits Proliferation and Induces Apoptosis of Colon Cancer Cells by Suppressing the AKT/mTOR Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Małgorzata Kapral

    2017-10-01

    Full Text Available Abstract: AKT, a serine/threonine protein kinase and mammalian target of rapamycin (mTOR plays a critical role in the proliferation and resistance to apoptosis that are essential to the development and progression of colon cancer. Therefore, AKT/mTOR signaling pathway has been recognized as an attractive target for anticancer therapy. Inositol hexaphosphate (InsP6, a natural occurring phytochemical, has been shown to have both preventive and therapeutic effects against various cancers, however, its exact molecular mechanisms of action are not fully understood. The aim of the in vitro study was to investigate the anticancer activity of InsP6 on colon cancer with the focus on inhibiting the AKT1 kinase and p70S6K1 as mTOR effector, in relation to proliferation and apoptosis of cells. The colon cancer Caco-2 cells were cultured using standard techniques and exposed to InsP6 at different concentrations (1 mM, 2.5 mM and 5 mM. Cellular proliferative activity was monitored by 5-bromo-2′-deoxyuridine (BrdU incorporation into cellular DNA. Flow cytometric analysis was performed for cell cycle progression and apoptosis studies. Real-time RT-qPCR was used to validate mRNA levels of CDNK1A, CDNK1B, CASP3, CASP9, AKT1 and S6K1 genes. The concentration of p21 protein as well as the activities of caspase 3, AKT1 and p70S6K1 were determined by the ELISA method. The results revealed that IP6 inhibited proliferation and stimulated apoptosis of colon cancer cells. This effect was mediated by an increase in the expression of genes encoding p21, p27, caspase 3, caspase 9 as well a decrease in transcription of AKT1 and S6K1. InsP6 suppressed phosphorylation of AKT1 and p70S6K1, downstream effector of mTOR. Based on these studies it may be concluded that InsP6 can reduce proliferation and induce apoptosis through inhibition of the AKT/mTOR pathway and mTOR effector followed by modulation of the expression and activity of several key components of these pathways in

  12. TSC1 and TSC2 regulate cilia length and canonical Hedgehog signaling via different mechanisms

    DEFF Research Database (Denmark)

    Rosengren, Thomas; Larsen, Lasse Jonsgaard; Pedersen, Lotte Bang

    2018-01-01

    Primary cilia are sensory organelles that coordinate multiple cellular signaling pathways, including Hedgehog (HH), Wingless/Int (WNT) and Transforming Growth Factor-β (TGF-β) signaling. Similarly, primary cilia have been implicated in regulation of mTOR signaling, in which Tuberous Sclerosis...... Complex proteins 1 and 2 (TSC1/2) negatively regulate protein synthesis by inactivating the mTOR complex 1 (mTORC1) at energy limiting states. Here we report that TSC1 and TSC2 regulate Smoothened (SMO)-dependent HH signaling in mouse embryonic fibroblasts (MEFs). Reduced SMO-dependent expression of Gli1...

  13. Quercetin inhibits transcriptional up-regulation of histamine H1 receptor via suppressing protein kinase C-δ/extracellular signal-regulated kinase/poly(ADP-ribose) polymerase-1 signaling pathway in HeLa cells.

    Science.gov (United States)

    Hattori, Masashi; Mizuguchi, Hiroyuki; Baba, Yuko; Ono, Shohei; Nakano, Tomohiro; Zhang, Qian; Sasaki, Yohei; Kobayashi, Makoto; Kitamura, Yoshiaki; Takeda, Noriaki; Fukui, Hiroyuki

    2013-02-01

    It has been reported that the histamine H1 receptor (H1R) gene is up-regulated in patients with allergic rhinitis and H1R expression level strongly correlates with the severity of allergy symptoms. Accordingly compounds that suppress the H1R gene expression are promising as useful anti-allergic medications. Recently, we demonstrated that histamine or phorbol-12-myristate-13-acetate (PMA) stimulation induced the up-regulation of H1R gene expression through the protein kinase Cδ (PKCδ)/extracellular signal-regulated kinase/poly(ADP-ribose) polymerase-1 signaling pathway in HeLa cells expressing H1R endogenously. Quercetin is one of the well-characterized flavonoids and it possesses many biological activities including anti-allergic activity. However, effect of quercetin on H1R signaling is remained unknown. In the present study, we examined the effect of quercetin on histamine- and PMA-induced up-regulation of H1R gene expression in HeLa cells. We also investigated its in vivo effects on the toluene-2,4-diisocyanate (TDI)-sensitized allergy model rats. Quercetin suppressed histamine- and PMA-induced up-regulation of H1R gene expression. Quercetin also inhibited histamine- or PMA-induced phosphorylation of Tyr(311) of PKCδ and translocation of PKCδ to the Golgi. Pre-treatment with quercetin for 3weeks suppressed TDI-induced nasal allergy-like symptoms and elevation of H1R mRNA in the nasal mucosa of TDI-sensitized rats. These data suggest that quercetin suppresses H1R gene expression by the suppression of PKCδ activation through the inhibition of its translocation to the Golgi. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Astragaloside IV suppresses transforming growth factor-β1 induced fibrosis of cultured mouse renal fibroblasts via inhibition of the MAPK and NF-κB signaling pathways

    Energy Technology Data Exchange (ETDEWEB)

    Che, Xiajing; Wang, Qin; Xie, Yuanyuan; Xu, Weijia; Shao, Xinghua; Mou, Shan, E-mail: shan_mou@126.com; Ni, Zhaohui, E-mail: doctor_nzh@126.com

    2015-09-04

    Renal fibrosis, a progressive process characterized by the accumulation of extracellular matrix (ECM) leading to organ dysfunction, is a characteristic of chronic kidney diseases. Among fibrogenic factors known to regulate the renal fibrotic process, transforming growth factor-β (TGF-β) plays a central role. In the present study, we examined the effect of Astragaloside IV (AS-IV), a component of the traditional Chinese medicinal plant Astragalus membranaceus, on the processes associated with renal fibrosis in cultured mouse renal fibroblasts treated with TGF-β1. RT-PCR, western blotting, immunofluorescence staining and collagen assays showed that AS-IV suppressed TGF-β1 induced fibroblast proliferation, transdifferentiation, and ECM production in a dose-dependent manner. Examination of the underlying mechanisms showed that the effect of AS-IV on the inhibition of fibroblast differentiation and ECM formation were mediated by its modulation of the activity of the MAPK and NF-κB signaling pathways. Taken together, our results indicate that AS-IV alleviates renal interstitial fibrosis via a mechanism involving the MAPK and NF-κB signaling pathways and demonstrate the therapeutic potential of AS-IV for the treatment of chronic kidney diseases. - Highlights: • AS-IV suppressed TGF-β1 induced renal fibroblast proliferation. • AS-IV suppressed TGF-β1 induced renal fibroblast transdifferentiation. • AS-IV suppressed TGF-β1 induced ECM production. • AS-IV alleviates renal fibrosis via the MAPK and NF-κB signaling pathways.

  15. Caloric Restriction Mimetic 2-Deoxyglucose Alleviated Inflammatory Lung Injury via Suppressing Nuclear Pyruvate Kinase M2–Signal Transducer and Activator of Transcription 3 Pathway

    Directory of Open Access Journals (Sweden)

    Kai Hu

    2018-03-01

    Full Text Available Inflammation is an energy-intensive process, and caloric restriction (CR could provide anti-inflammatory benefits. CR mimetics (CRM, such as the glycolytic inhibitor 2-deoxyglucose (2-DG, mimic the beneficial effects of CR without inducing CR-related physiologic disturbance. This study investigated the potential anti-inflammatory benefits of 2-DG and the underlying mechanisms in mice with lipopolysaccharide (LPS-induced lethal endotoxemia. The results indicated that pretreatment with 2-DG suppressed LPS-induced elevation of tumor necrosis factor alpha and interleukin 6. It also suppressed the upregulation of myeloperoxidase, attenuated Evans blue leakage, alleviated histological abnormalities in the lung, and improved the survival of LPS-challenged mice. Treatment with 2-DG had no obvious effects on the total level of pyruvate kinase M2 (PKM2, but it significantly suppressed LPS-induced elevation of PKM2 in the nuclei. Prevention of PKM2 nuclear accumulation by ML265 mimicked the anti-inflammatory benefits of 2-DG. In addition, treatment with 2-DG or ML265 suppressed the phosphorylation of nuclear signal transducer and activator of transcription 3 (STAT3. Inhibition of STAT3 by stattic suppressed LPS-induced inflammatory injury. Interestingly, posttreatment with 2-DG at the early stage post-LPS challenge also improved the survival of the experimental animals. This study found that treatment with 2-DG, a representative CRM, provided anti-inflammatory benefits in lethal inflammation. The underlying mechanisms included suppressed nuclear PKM2-STAT3 pathway. These data suggest that 2-DG might have potential value in the early intervention of lethal inflammation.

  16. Caloric Restriction Mimetic 2-Deoxyglucose Alleviated Inflammatory Lung Injury via Suppressing Nuclear Pyruvate Kinase M2-Signal Transducer and Activator of Transcription 3 Pathway.

    Science.gov (United States)

    Hu, Kai; Yang, Yongqiang; Lin, Ling; Ai, Qing; Dai, Jie; Fan, Kerui; Ge, Pu; Jiang, Rong; Wan, Jingyuan; Zhang, Li

    2018-01-01

    Inflammation is an energy-intensive process, and caloric restriction (CR) could provide anti-inflammatory benefits. CR mimetics (CRM), such as the glycolytic inhibitor 2-deoxyglucose (2-DG), mimic the beneficial effects of CR without inducing CR-related physiologic disturbance. This study investigated the potential anti-inflammatory benefits of 2-DG and the underlying mechanisms in mice with lipopolysaccharide (LPS)-induced lethal endotoxemia. The results indicated that pretreatment with 2-DG suppressed LPS-induced elevation of tumor necrosis factor alpha and interleukin 6. It also suppressed the upregulation of myeloperoxidase, attenuated Evans blue leakage, alleviated histological abnormalities in the lung, and improved the survival of LPS-challenged mice. Treatment with 2-DG had no obvious effects on the total level of pyruvate kinase M2 (PKM2), but it significantly suppressed LPS-induced elevation of PKM2 in the nuclei. Prevention of PKM2 nuclear accumulation by ML265 mimicked the anti-inflammatory benefits of 2-DG. In addition, treatment with 2-DG or ML265 suppressed the phosphorylation of nuclear signal transducer and activator of transcription 3 (STAT3). Inhibition of STAT3 by stattic suppressed LPS-induced inflammatory injury. Interestingly, posttreatment with 2-DG at the early stage post-LPS challenge also improved the survival of the experimental animals. This study found that treatment with 2-DG, a representative CRM, provided anti-inflammatory benefits in lethal inflammation. The underlying mechanisms included suppressed nuclear PKM2-STAT3 pathway. These data suggest that 2-DG might have potential value in the early intervention of lethal inflammation.

  17. Taspine derivative 12k suppressed A549 cell migration through the Wnt/β-catenin and EphrinB2 signaling pathway.

    Science.gov (United States)

    Dai, Bingling; Ma, Yujiao; Yang, Tianfeng; Wang, Wenjie; Zhang, Yanmin

    2017-03-01

    12k, a taspine derivative, has been demonstrated to have the potent anti-tumor activity in lung cancer and colorectal cancer. The study aims to further explore the underlying mechanisms of 12k on A549 cell migration in vitro. Our data demonstrated that 12k negatively regulated Wnt signaling pathway by suppressing the phosphorylation of LRP5/6, and inhibiting the expression and nuclear translocation of β-catenin. 12k was shown to downregulate MMP3 and MMP7 expression which regulated by β-catenin interacts with TCF/LEF in the nucleus, and effectively impaired the related migration protein expression of MMP2 and MMP9 in A549 cells. In addition, 12k repressed the EphrinB2 and its PDZ protein, impairing the VEGFR2 and VEGFR3 expression in A549 cells, as well as inhibited the downstream of VEGFR2 included PI3K/AKT/mTOR and ERK/MAPK signaling pathways. Taken together, our findings revealed that 12k suppressed migration of A549 cells through the Wnt/β-catenin signaling pathway and EphrinB2 related signaling pathway. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  18. The cyclic GMP-AMP synthetase-STING signaling pathway is required for both the innate immune response against HBV and the suppression of HBV assembly.

    Science.gov (United States)

    Dansako, Hiromichi; Ueda, Youki; Okumura, Nobuaki; Satoh, Shinya; Sugiyama, Masaya; Mizokami, Masashi; Ikeda, Masanori; Kato, Nobuyuki

    2016-01-01

    During viral replication, the innate immune response is induced through the recognition of viral replication intermediates by host factor(s). One of these host factors, cyclic GMP-AMP synthetase (cGAS), was recently reported to be involved in the recognition of viral DNA derived from DNA viruses. However, it is uncertain whether cGAS is involved in the recognition of hepatitis B virus (HBV), which is a hepatotropic DNA virus. In the present study, we demonstrated that HBV genome-derived double-stranded DNA induced the innate immune response through cGAS and its adaptor protein, stimulator of interferon genes (STING), in human hepatoma Li23 cells expressing high levels of cGAS. In addition, we demonstrated that HBV infection induced ISG56 through the cGAS-STING signaling pathway. This signaling pathway also showed an antiviral response towards HBV through the suppression of viral assembly. From these results, we conclude that the cGAS-STING signaling pathway is required for not only the innate immune response against HBV but also the suppression of HBV assembly. The cGAS-STING signaling pathway may thus be a novel target for anti-HBV strategies. © 2015 FEBS.

  19. Baicalein suppresses 17-β-estradiol-induced migration, adhesion and invasion of breast cancer cells via the G protein-coupled receptor 30 signaling pathway.

    Science.gov (United States)

    Shang, Dandan; Li, Zheng; Zhu, Zhuxia; Chen, Huamei; Zhao, Lujun; Wang, Xudong; Chen, Yan

    2015-04-01

    Flavonoids are structurally similar to steroid hormones, particularly estrogens, and therefore have been studied for their potential effects on hormone-dependent cancers. Baicalein is the primary flavonoid derived from the root of Scutellaria baicalensis Georgi. In the present study, we investigated the effects of baicalein on 17β-estradiol (E2)-induced migration, adhesion and invasion of MCF-7 and SK-BR-3 breast cancer cells. The results demonstrated that baicalein suppressed E2-stimulated wound-healing migration and cell‑Matrigel adhesion, and ameliorated E2-promoted invasion across a Matrigel-coated Transwell membrane. Furthermore, baicalein interfered with E2-induced novel G protein-coupled estrogen receptor (GPR30)-related signaling, including a decrease in tyrosine phosphorylation of epidermal growth factor receptor (EGFR) as well as phosphorylation of extracellular signal-regulated kinase (ERK) and serine/threonine kinase Akt, without affecting GPR30 expression. The results also showed that baicalein suppressed the expression of GPR30 target genes, cysteine-rich 61 (CYR61) and connective tissue growth factor (CTGF) induced by E2. Furthermore, baicalein prevented GPR30-related signaling activation and upregulation of CYR61 and CTGF mRNA levels induced by G1, a specific GPR 30 agonist. The results suggest that baicalein inhibits E2-induced migration, adhesion and invasion through interfering with GPR30 signaling pathway activation, which indicates that it may act as a therapeutic candidate for the treatment of GPR30-positive breast cancer metastasis.

  20. Diffusion-weighted whole-body magnetic resonance imaging with background body signal suppression/T2 image fusion for the diagnosis of acute cholecystitis

    Science.gov (United States)

    Tomizawa, Minoru; Shinozaki, Fuminobu; Tanaka, Satomi; Sunaoshi, Takafumi; Kano, Daisuke; Sugiyama, Eriko; Shite, Misaki; Haga, Ryouta; Fukamizu, Yoshiya; Fujita, Toshiyuki; Kagayama, Satoshi; Hasegawa, Rumiko; Shirai, Yoshinori; Motoyoshi, Yasufumi; Sugiyama, Takao; Yamamoto, Shigenori; Ishige, Naoki

    2017-01-01

    Prompt and accurate diagnosis is critical in the treatment of acute cholecystitis. Diffusion-weighted whole-body magnetic resonance imaging with background body signal suppression/T2 image fusion (DWIBS/T2) identifies areas with high signal intensity, corresponding to inflammation. In the present study, the records and images of patients with acute cholecystitis who underwent DWIBS/T2 between January 2013 and March 2014 were retrospectively analyzed. A total of 11 patients with acute cholecystitis were enrolled. In one patient, DWIBS/T2 identified a thickened wall and high signal intensity, with high signal intensity in the pericholecystic space that suggested localized peritonitis. Positive DWIBS/T2 results indicating acute cholecystitis were obtained in 10/11 patients, with a sensitivity of 90.9%. In addition, wall thickening and high signal intensity were absent in DWIBS/T2 images when wall thickening was not detected by computed tomography. Wall thickening and high signal intensity was attenuated when patients with acute cholecystitis were clinically treated. These data suggest that a thickened gallbladder wall and high signal intensity are indicative of acute cholecystitis and that DWIBS/T2 may be a useful technique in evaluating the severity of acute cholecystitis. PMID:28672991

  1. Loss of Rictor in Monocyte/Macrophages Suppresses Their Proliferation and Viability Reducing Atherosclerosis in LDLR Null Mice

    Directory of Open Access Journals (Sweden)

    Vladimir R. Babaev

    2018-02-01

    Full Text Available BackgroundRictor is an essential component of mammalian target of rapamycin (mTOR complex 2 (mTORC2, a conserved serine/threonine kinase that may play a role in cell proliferation, survival and innate or adaptive immune responses. Genetic loss of Rictor inactivates mTORC2, which directly activates Akt S473 phosphorylation and promotes pro-survival cell signaling and proliferation.Methods and resultsTo study the role of mTORC2 signaling in monocytes and macrophages, we generated mice with myeloid lineage-specific Rictor deletion (MRictor−/−. These MRictor−/− mice exhibited dramatic reductions of white blood cells, B-cells, T-cells, and monocytes but had similar levels of neutrophils compared to control Rictor flox-flox (Rictorfl/fl mice. MRictor−/− bone marrow monocytes and peritoneal macrophages expressed reduced levels of mTORC2 signaling and decreased Akt S473 phosphorylation, and they displayed significantly less proliferation than control Rictorfl/fl cells. In addition, blood monocytes and peritoneal macrophages isolated from MRictor−/− mice were significantly more sensitive to pro-apoptotic stimuli. In response to LPS, MRictor−/− macrophages exhibited the M1 phenotype with higher levels of pro-inflammatory gene expression and lower levels of Il10 gene expression than control Rictorfl/fl cells. Further suppression of LPS-stimulated Akt signaling with a low dose of an Akt inhibitor, increased inflammatory gene expression in macrophages, but genetic inactivation of Raptor reversed this rise, indicating that mTORC1 mediates this increase of inflammatory gene expression. Next, to elucidate whether mTORC2 has an impact on atherosclerosis in vivo, female and male Ldlr null mice were reconstituted with bone marrow from MRictor−/− or Rictorfl/fl mice. After 10 weeks of the Western diet, there were no differences between the recipients of the same gender in body weight, blood glucose or plasma lipid levels. However, both

  2. Catechol Groups Enable Reactive Oxygen Species Scavenging-Mediated Suppression of PKD-NFkappaB-IL-8 Signaling Pathway by Chlorogenic and Caffeic Acids in Human Intestinal Cells.

    Science.gov (United States)

    Shin, Hee Soon; Satsu, Hideo; Bae, Min-Jung; Totsuka, Mamoru; Shimizu, Makoto

    2017-02-20

    Chlorogenic acid (CHA) and caffeic acid (CA) are phenolic compounds found in coffee, which inhibit oxidative stress-induced interleukin (IL)-8 production in intestinal epithelial cells, thereby suppressing serious cellular injury and inflammatory intestinal diseases. Therefore, we investigated the anti-inflammatory mechanism of CHA and CA, both of which inhibited hydrogen peroxide (H₂O₂)-induced IL-8 transcriptional activity. They also significantly suppressed nuclear factor kappa-light-chain-enhancer of activated B cells ( NF-κB ) transcriptional activity, nuclear translocation of the p65 subunit, and phosphorylation of IκB kinase (IKK). Additionally, upstream of IKK, protein kinase D (PKD) was also suppressed. Finally, we found that they scavenged H₂O₂-induced reactive oxygen species (ROS) and the functional moiety responsible for the anti-inflammatory effects of CHA and CA was the catechol group. Therefore, we conclude that the presence of catechol groups in CHA and CA allows scavenging of intracellular ROS, thereby inhibiting H₂O₂-induced IL-8 production via suppression of PKD-NF-κB signaling in human intestinal epithelial cells.

  3. Catechol Groups Enable Reactive Oxygen Species Scavenging-Mediated Suppression of PKD-NFkappaB-IL-8 Signaling Pathway by Chlorogenic and Caffeic Acids in Human Intestinal Cells

    Directory of Open Access Journals (Sweden)

    Hee Soon Shin

    2017-02-01

    Full Text Available Chlorogenic acid (CHA and caffeic acid (CA are phenolic compounds found in coffee, which inhibit oxidative stress-induced interleukin (IL-8 production in intestinal epithelial cells, thereby suppressing serious cellular injury and inflammatory intestinal diseases. Therefore, we investigated the anti-inflammatory mechanism of CHA and CA, both of which inhibited hydrogen peroxide (H2O2-induced IL-8 transcriptional activity. They also significantly suppressed nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB transcriptional activity, nuclear translocation of the p65 subunit, and phosphorylation of IκB kinase (IKK. Additionally, upstream of IKK, protein kinase D (PKD was also suppressed. Finally, we found that they scavenged H2O2-induced reactive oxygen species (ROS and the functional moiety responsible for the anti-inflammatory effects of CHA and CA was the catechol group. Therefore, we conclude that the presence of catechol groups in CHA and CA allows scavenging of intracellular ROS, thereby inhibiting H2O2-induced IL-8 production via suppression of PKD-NF-κB signaling in human intestinal epithelial cells.

  4. Dietary L-Lysine Suppresses Autophagic Proteolysis and Stimulates Akt/mTOR Signaling in the Skeletal Muscle of Rats Fed a Low-Protein Diet.

    Science.gov (United States)

    Sato, Tomonori; Ito, Yoshiaki; Nagasawa, Takashi

    2015-09-23

    Amino acids, especially L-leucine, regulate protein turnover in skeletal muscle and have attracted attention as a means of increasing muscle mass in people suffering from malnutrition, aging (sarcopenia), or a bedridden state. We previously showed that oral administration of L-lysine (Lys) by gavage suppressed proteolysis in skeletal muscles of fasted rats. However, the intake of Lys in the absence of other dietary components is unlikely in a non-experimental setting, and other dietary components may interfere with the suppressive effect of Lys on proteolysis. We supplemented Lys to a 10% casein diet and investigated the effect of Lys on proteolysis and autophagy, a major proteolytic system, in the skeletal muscle of rats. The rate of proteolysis was evaluated from 3-methylhisitidine (MeHis) released from isolated muscles, in plasma, and excreted in urine. Supplementing lysine with the 10% casein diet decreased the rate of proteolysis induced by intake of a low-protein diet. The upregulated autophagy activity [light chain 3 (LC3)-II/total LC3] caused by a low-protein diet was reduced, and the Akt/mTOR signaling pathway was activated by Lys. Importantly, continuous feeding of a Lys-rich 10% casein diet for 15 days increased the masses of the soleus and gastrocnemius muscles. Taken together, supplementation of Lys to a low-protein diet suppresses autophagic proteolysis through the Akt/mTOR signaling pathway, and continuous feeding of a Lys-rich diet may increase skeletal muscle mass.

  5. Increased signal intensity on fat-suppressed three-dimensional T1-weighted pulse sequences in patellar tendon: magic angle effect?

    Energy Technology Data Exchange (ETDEWEB)

    Karantanas, A.H.; Zibis, A.H. [CT-MRI Dept., Larissa General Hospital, Larissa (Greece); Papanikolaou, N. [Radiology Dept., University of Crete, Heraklion (Greece)

    2001-02-01

    Objective. To assess the frequency of increased signal intensity in the patellar tendon using three-dimensional T1-weighted MRI pulse sequences. Design and patients. Sixty patients were examined with a 1.0 T scanner (15mT/m gradient strength) using a quadrature coil. Three pulse sequences were applied in the sagittal plane: PD turbo spin echo (PD-TSE), 3D T1-weighted gradient echo with fat suppression (3D-T1-FFE-FS) and 3D T1-weighted echo planar imaging with fat suppression (3D-T1-EPI-FS). The high signal intensity areas were measured in their maximum length. The angle of the patellar tendon relative to the main field position was measured in the same slice. In eight patients with anterior knee pain, and in 11 with no anterior knee pain, a fourth T2-weighted TSE pulse sequence (T2-TSE) was obtained to rule out patellar tendinitis. Results. The correlation of the high signal intensity areas with the relative position of the tendon was found to be significant with the 3D sequences (P=0.03 for 3D-T1-FFE-FS and P=0.003 for 3D-T1-EPI-FS). The length of the high signal intensity area in the tendon was 5.4 mm with 3D-T1-FFE-FS, 4.9 mm with 3D-T1-EPI-FS and 3.1 mm with PD-TSE images. No patellar tendinitis was demonstrated on the T2-TSE images. Conclusion. The magic angle effect is commonly observed in the 3D based T1-weighted pulse sequences with fat suppression. The presence of the above sign must be recognized by radiologists, so that misdiagnosis of patellar tendinitis is avoided. (orig.)

  6. Nobiletin induces inhibitions of Ras activity and mitogen-activated protein kinase kinase/extracellular signal-regulated kinase signaling to suppress cell proliferation in C6 rat glioma cells.

    Science.gov (United States)

    Aoki, Koichi; Yokosuka, Akihito; Mimaki, Yoshihiro; Fukunaga, Kohji; Yamakuni, Tohru

    2013-01-01

    Ras, a small G-protein, physiologically directs cell proliferation and cell cycle via regulation of mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling cascade. Dysregulation of Ras/MEK/ERK signaling has been reported to cause tumorigenesis and gliomas. Nobiletin, a citrus flavonoid, has been shown to have anti-tumor cells action. However, it remains elusive whether nobiletin could affect Ras activity. In this study, we provide the first evidence that nobiletin suppresses the proliferation by inhibiting Ras activity in C6 glioma cells, a rat glioma cell line. First, Ras pull-down assay showed that nobiletin inhibits Ras activity in a concentration-dependent manner in C6 cells. Second, farnesyltransferase inhibitor I, a Ras inhibitor, and U0126, a MEK inhibitor, induced an inhibition of the cell proliferation in C6 cells, while the cell proliferation was inhibited by nobiletin as well. Third, western blotting revealed that nobiletin showed inhibitory effects on MEK and ERK phopsphorylation levels in a concentration-dependent manner. Finally, such an inhibitory effect on the level of ERK phosphorylation by nobiletin was appreciably prevented by Gö6976, a selective inhibitor of conventional protein kinase Cs (PKCs) showing Ca(2+)-sensitivity, while GF109203X, a general inhibitor for PKCs, and BAPTA, a cell-permeable Ca(2+) chelator, to a lesser extent, suppressed a reduction of the phosphorylation. These findings suggest that the proliferation of C6 cells is Ras- and MEK/ERK signaling-dependent, and that nobiletin suppresses the cell proliferation by inhibiting Ras activity and MEK/ERK signaling cascade probably via a Ca(2+)-sensitive PKC-dependent mechanism. Thus, the natural compound has potential to be a therapeutic agent for glioma.

  7. A pterostilbene derivative suppresses osteoclastogenesis by regulating RANKL-mediated NFκB and MAPK signaling in RAW264.7 cells.

    Science.gov (United States)

    Nikhil, Kumar; Sharan, Shruti; Roy, Partha

    2015-12-01

    A dysfunctional osteoclast activity is often the cause of bone destructive diseases, such as osteoporosis, periodontitis, erosive arthritis, and cancer. The NFκB ligand (RANKL) has been identified as a major mediator of bone resorption. Agents that suppress RANKL signaling have the potential to inhibit bone resorption or osteoclastogenesis. The present study aimed to determine the effect of a pterostilbene derivative (PTERC-T) for suppressing RANKL or tumor cells-induced osteoclastogenesis in RAW264.7 murine macrophages. Cytotoxicity was measured by MTT assay and inhibitory effect on osteoclastogenesis was analyzed by counting the number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells and measuring the expression levels of the osteoclast-specific genes. The reactive oxygen species (ROS) generation was detected by FACS. Further, signaling pathways were analyzed by immunofluorescence and immunoblot analyses. PTERC-T suppressed the differentiation of monocytes to osteoclasts in a dose and time-dependent manner. The expression of osteoclast marker genes like TRAP, cathepsin K (CTSK), matrix metalloproteinase 9 (MMP9) and transcription factors c-Fos, and nuclear factor of activated T cells cytoplasmic 1 (NFATc1) were also diminished by PTERC-T. PTERC-T scavenged intracellular ROS generation within osteoclast precursors during RANKL-stimulated osteoclastogenesis. Mechanistically, PTERC-T abrogated the phosphorylation of MAPKs (ERK and JNK) and inhibited RANKL-induced activation of NFκB by suppressing IκBα phosphorylation and preventing NFκB/p65 nuclear translocation. This study thus identifies PTERC-T as an inhibitor of osteoclast formation and provides evidence for its role in preventing osteoporosis and other bone related disorders. However, further studies are needed to establish its efficacy in vivo. Copyright © 2015 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights

  8. Nonstructural 5A Protein of Hepatitis C Virus Interferes with Toll-Like Receptor Signaling and Suppresses the Interferon Response in Mouse Liver.

    Directory of Open Access Journals (Sweden)

    Takeya Tsutsumi

    Full Text Available The hepatitis C virus nonstructural protein NS5A is involved in resistance to the host immune response, as well as the viral lifecycle such as replication and maturation. Here, we established transgenic mice expressing NS5A protein in the liver and examined innate immune responses against lipopolysaccharide (LPS in vivo. Intrahepatic gene expression levels of cytokines such as interleukin-6, tumor necrosis factor-α, and interferon-γ were significantly suppressed after LPS injection in the transgenic mouse liver. Induction of the C-C motif chemokine ligand 2, 4, and 5 was also suppressed. Phosphorylation of the signal transducer and activator of transcription 3, which is activated by cytokines, was also reduced, and expression levels of interferon-stimulated genes, 2'-5' oligoadenylate synthase, interferon-inducible double-stranded RNA-activated protein kinase, and myxovirus resistance 1 were similarly suppressed. Since LPS binds to toll-like receptor 4 and stimulates the downstream pathway leading to induction of these genes, we examined the extracellular signal-regulated kinase and IκB-α. The phosphorylation levels of these molecules were reduced in transgenic mouse liver, indicating that the pathway upstream of the molecules was disrupted by NS5A. Further analyses revealed that the interaction between interleukin-1 receptor-associated kinase-1 and tumor necrosis factor receptor associated factor-6 was dispersed in transgenic mice, suggesting that NS5A may interfere with this interaction via myeloid differentiation primary response gene 88, which was shown to interact with NS5A. Since the gut microbiota, a source of LPS, is known to be associated with pathological conditions in liver diseases, our results suggest the involvement of NS5A in the pathogenesis of HCV infected-liver via the suppression of innate immunity.

  9. Erythropoietin suppresses epithelial to mesenchymal transition and intercepts Smad signal transduction through a MEK-dependent mechanism in pig kidney (LLC-PK1) cell lines

    International Nuclear Information System (INIS)

    Chen, Chien-Liang; Chou, Kang-Ju; Lee, Po-Tsang; Chen, Ying-Shou; Chang, Tsu-Yuan; Hsu, Chih-Yang; Huang, Wei-Chieh; Chung, Hsiao-Min; Fang, Hua-Chang

    2010-01-01

    Purpose: Tumor growth factor-β1 (TGF-β1) plays a pivotal role in processes like kidney epithelial-mesenchymal transition (EMT) and interstitial fibrosis, which correlate well with progression of renal disease. Little is known about underlying mechanisms that regulate EMT. Based on the anatomical relationship between erythropoietin (EPO)-producing interstitial fibroblasts and adjacent tubular cells, we investigated the role of EPO in TGF-β1-mediated EMT and fibrosis in kidney injury. Methods: We examined apoptosis and EMT in TGF-β1-treated LLC-PK1 cells in the presence or absence of EPO. We examined the effect of EPO on TGF-β1-mediated Smad signaling. Apoptosis and cell proliferation were assessed with flow cytometry and hemocytometry. We used Western blotting and indirect immunofluorescence to evaluate expression levels of TGF-β1 signal pathway proteins and EMT markers. Results: We demonstrated that ZVAD-FMK (a caspase inhibitor) inhibited TGF-β1-induced apoptosis but did not inhibit EMT. In contrast, EPO reversed TGF-β1-mediated apoptosis and also partially inhibited TGF-β1-mediated EMT. We showed that EPO treatment suppressed TGF-β1-mediated signaling by inhibiting the phosphorylation and nuclear translocation of Smad 3. Inhibition of mitogen-activated protein kinase kinase 1 (MEK 1) either directly with PD98059 or with MEK 1 siRNA resulted in inhibition of EPO-mediated suppression of EMT and Smad signal transduction in TGF-β1-treated cells. Conclusions: EPO inhibited apoptosis and EMT in TGF-β1-treated LLC-PK1 cells. This effect of EPO was partially mediated by a mitogen-activated protein kinase-dependent inhibition of Smad signal transduction.

  10. Andrographolide suppresses proliferation of human colon cancer SW620 cells through the TLR4/NF-κB/MMP-9 signaling pathway.

    Science.gov (United States)

    Zhang, Rui; Zhao, Jian; Xu, Jian; Jiao, De-Xin; Wang, Jian; Gong, Zhi-Qiang; Jia, Jian-Hui

    2017-10-01

    Modern pharmacological research has revealed that andrographolide has various functions, including anti-bacterial, anti-inflammatory and anti-viral effects, immunoregulation, treating cardiovascular and cerebrovascular diseases, and prevention and treatment of alcoholic liver injury. The present study investigated whether andrographolide suppresses the proliferation of human colon cancer cell through the Toll-like receptor 4 (TLR4)/nuclear factor (NF)-κB/matrix metalloproteinase-9 (MMP-9) signaling pathway. The MTT assay and lactate dehydrogenase assay were used to evaluate the anticancer effects of andrographolide on cell proliferation and cytotoxicity in human colon cancer SW620 cells. Flow cytometry was used to analyze the anticancer effects of andrographolide on apoptosis by Annexin V-fluorescein isothiocyanate/propidium iodide kit. The effects of andrographolide on the activity of caspase-3/9 were measured using ELISA. Western blot analysis was also used to analyze the protein expression of TLR4, myeloid differentiation primary response gene 88 (MyD88), NF-κB-p65 and MMP-9. In the present study, it was found that andrographolide suppressed the cell proliferation, augmented cytotoxicity, evoked cell apoptosis and activated caspase-3/9 activities in human colon cancer SW620 cells. The results revealed that the anti-proliferation effects of andrographolide on the SW620 cells was associated with the inhibition of TLR4, MyD88, NF-κB-p65 and MMP-9 signaling activation. The results suggest that andrographolide is a promising drug for treatment of human colon cancer via suppression of the TLR4/NF-κB/MMP-9 signaling pathway.

  11. Comparison of facet joint activity on 99mTc-MDP SPECT/CT with facet joint signal change on MRI with fat suppression.

    Science.gov (United States)

    Lehman, Vance T; Murphy, Robert C; Schenck, Louis A; Carter, Rickey E; Johnson, Geoffrey B; Kotsenas, Amy L; Morris, Jonathan M; Nathan, Mark A; Wald, John T; Maus, Timothy P

    2016-01-01

    We compared signal change on magnetic resonance imaging (MRI) with fat suppression and bone scan activity of lumbar facet joints to determine if these two imaging findings are correlated. We retrospectively identified all patients who underwent imaging of the lumbar spine for pain evaluation using both technetium-99m methylene disphosphonate single-photon emission computed tomography/computed tomography (99mTc-MDP SPECT/CT) and MRI with at least one fat-suppressed T2- or T1-weighted sequence with gadolinium enhancement within a 180-day interval, at our institution between 1 January 2008 and 19 February 2013. Facet joint activity on 99mTc-MDP SPECT/CT and peri-facet signal change on MRI were rated as normal or increased. Agreement between the two examination types were determined with the κ and prevalence-adjusted bias-adjusted κ (PABAK) statistics. This study included 60 patients (28 male, 47%), with a mean age of 49±19.7 years (range, 12-93 years). The κ value indicated no agreement between 99mTc-MDP SPECT/CT and MRI (κ=-0.026; 95% confidence interval: -0.051, 0.000). The PABAK values were fair to high at each spinal level, which suggests that relatively low disease prevalence lowered the κ values. Together, the κ and PABAK values indicate that there is some degree of intermodality agreement, but that it is not consistent. Overall, facet joint signal change on fat-suppressed MRI did not always correlate with increased 99mTc-MDP SPECT/CT activity. MRI and 99mTc-MDP SPECT/CT for facet joint evaluation should not be considered interchangeable examinations in clinical practice or research.

  12. Identification of beta-escin as a novel inhibitor of signal transducer and activator of transcription 3/Janus-activated kinase 2 signaling pathway that suppresses proliferation and induces apoptosis in human hepatocellular carcinoma cells.

    Science.gov (United States)

    Tan, Sandra Min-Li; Li, Feng; Rajendran, Peramaiyan; Kumar, Alan Prem; Hui, Kam M; Sethi, Gautam

    2010-07-01

    The activation of signal transducer and activator of transcription 3 (STAT3) has been linked with the proliferation, survival, invasion, and angiogenesis of a variety of human cancer cells, including hepatocellular carcinoma (HCC). Agents that can suppress STAT3 activation have potential for the prevention and treatment of HCC. In this study, we tested an agent, beta-escin, for its ability to suppress STAT3 activation. We found that beta-escin, a pentacyclic triterpenoid, inhibited both constitutive and interleukin-6-inducible STAT3 activation in a dose- and time-dependent manner in HCC cells. The suppression was mediated through the inhibition of activation of upstream kinases c-Src, Janus-activated kinase 1, and Janus-activated kinase 2. Vanadate treatment reversed the beta-escin-induced down-regulation of STAT3, suggesting the involvement of a tyrosine phosphatase. Indeed, we found that beta-escin induced the expression of tyrosine phosphatase Src homology phosphatase 1 that correlated with the down-regulation of constitutive STAT3 activation. beta-Escin also down-regulated the expression of STAT3-regulated gene products, such as cyclin D1, Bcl-2, Bcl-xL, survivin, Mcl-1, and vascular endothelial growth factor. Finally, beta-escin inhibited proliferation and also substantially potentiated the apoptotic effects of paclitaxel and doxorubicin in HCC cells. Overall, these results suggest that beta-escin is a novel blocker of STAT3 activation that may have potential in the suppression of proliferation and chemosensitization in HCC.

  13. Resveratrol suppresses prostaglandin F(2α)-induced osteoprotegerin synthesis in osteoblasts: inhibition of the MAP kinase signaling.

    Science.gov (United States)

    Kuroyanagi, Gen; Tokuda, Haruhiko; Matsushima-Nishiwaki, Rie; Kondo, Akira; Mizutani, Jun; Kozawa, Osamu; Otsuka, Takanobu

    2014-01-15

    Resveratrol, a natural polyphenol abundantly found in grape skins and red wine, possesses various beneficial properties for human health. In the present study, we investigated the mechanism underlying the effects of prostaglandin F2α (PGF2α) on osteoprotegerin (OPG) synthesis and of resveratrol on the OPG synthesis in osteoblast-like MC3T3-E1 cells. PGF2α stimulated both the release of the OPG protein and the expression of OPG mRNA. Treatment with PD98059, SB203580 and SP600125, specific inhibitors of MEK1/2, p38 mitogen-activated protein (MAP) kinase and stress-activated protein kinase/c-jun N-terminal kinase (SAPK/JNK) all suppressed the OPG release induced by PGF2α. Resveratrol also significantly reduced the PGF2α-stimulated OPG release and the mRNA levels of OPG. Similarly, treatment with SRT1720, an activator of SIRT1, also suppressed the PGF2α-stimulated OPG release. Resveratrol and SRT1720 both attenuated the phosphorylation of p44/p42 MAP kinase, MEK1/2, Raf-1, p38 MAP kinase and SAPK/JNK induced by PGF2α. These findings strongly suggest that resveratrol suppresses PGF2α-stimulated OPG synthesis by inhibiting the MAP kinase pathways in osteoblasts, and that the effect is mediated via SIRT1 activation. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Beta-adrenergic signaling promotes tumor angiogenesis and prostate cancer progression through HDAC2-mediated suppression of thrombospondin-1.

    Science.gov (United States)

    Hulsurkar, M; Li, Z; Zhang, Y; Li, X; Zheng, D; Li, W

    2017-03-01

    Chronic behavioral stress and beta-adrenergic signaling have been shown to promote cancer progression, whose underlying mechanisms are largely unclear, especially the involvement of epigenetic regulation. Histone deacetylase-2 (HDAC2), an epigenetic regulator, is critical for stress-induced cardiac hypertrophy. It is unknown whether it is necessary for beta-adrenergic signaling-promoted cancer progression. Using xenograft models, we showed that chronic behavioral stress and beta-adrenergic signaling promote angiogenesis and prostate cancer progression. HDAC2 was induced by beta-adrenergic signaling in vitro and in mouse xenografts. We next uncovered that HDAC2 is a direct target of cAMP response element-binding protein (CREB) that is activated by beta-adrenergic signaling. Notably, HDAC2 is necessary for beta-adrenergic signaling to induce angiogenesis. We further demonstrated that, upon CREB activation, HDAC2 represses thrombospondin-1 (TSP1), a potent angiogenesis inhibitor, through epigenetic regulation. Together, these data establish a novel pathway that HDAC2 and TSP1 act downstream of CREB activation in beta-adrenergic signaling to promote cancer progression.

  15. Inhibition of canonical WNT signaling pathway by β-catenin/CBP inhibitor ICG-001 ameliorates liver fibrosis in vivo through suppression of stromal CXCL12.

    Science.gov (United States)

    Akcora, Büsra Öztürk; Storm, Gert; Bansal, Ruchi

    2018-03-01

    Quiescent hepatic stellate cells (HSCs), in response to liver injury, undergo characteristic morphological transformation into proliferative, contractile and ECM-producing myofibroblasts. In this study, we investigated the implication of canonical Wnt signaling pathway in HSCs and liver fibrogenesis. Canonical Wnt signaling pathway activation and inhibition using β-catenin/CBP inhibitor ICG001 was examined in-vitro in TGFβ-activated 3T3, LX2, primary human HSCs, and in-vivo in CCl 4 -induced acute liver injury mouse model. Fibroblasts-conditioned medium studies were performed to assess the Wnt-regulated paracrine factors involved in crosstalk between HSCs-macrophages and HSCs-endothelial cells. Canonical Wnt signaling pathway components were significantly up-regulated in-vitro and in-vivo. In-vitro, ICG-001 significantly inhibited fibrotic parameters, 3D-collagen contractility and wound healing. Conditioned medium induced fibroblasts-mediated macrophage and endothelial cells activation was significantly inhibited by ICG-001. In-vivo, ICG-001 significantly attenuated collagen accumulation and HSC activation. Interestingly, ICG-001 drastically inhibited macrophage infiltration, intrahepatic inflammation and angiogenesis. We further analyzed the paracrine factors involved in Wnt-mediated effects and found CXCL12 was significantly suppressed both in-vitro and in-vivo following Wnt inhibition. Wnt-regulated CXCL12 secretion from activated HSCs potentiated macrophage infiltration and activation, and angiogenesis. Pharmacological inhibition of canonical Wnt signaling pathway via suppression of stromal CXCL12 suggests a potential therapeutic approach targeting activated HSCs in liver fibrosis. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  16. Folic acid inhibits dedifferentiation of PDGF-BB-induced vascular smooth muscle cells by suppressing mTOR/P70S6K signaling.

    Science.gov (United States)

    Pan, Sunlei; Lin, Hui; Luo, Hangqi; Gao, Feidan; Meng, Liping; Zhou, Changzuan; Jiang, Chengjian; Guo, Yan; Ji, Zheng; Chi, Jufang; Guo, Hangyuan

    2017-01-01

    Folic acid (FA) supplementation reduces the risk of atherosclerosis and stroke. Phenotypic change from differentiated to dedifferentiated vascular smooth muscle cells (VSMCs) plays an important role in atherosclerosis development; however, the exact mechanisms remain unknown. This study aimed to assess whether FA through mammalian target of rapamycin (mTOR)/P70S6K signaling inhibits platelet derived growth factor (PDGF-BB) induced VSMC dedifferentiation. VSMCs from primary cultures were identified by morphological observation and α-smooth muscle actin (α-SM-actin, α-SMA) immunocytochemistry. Then, VSMCs were induced by PDGF-BB and treated with varying FA concentrations. Rapamycin and MHY-1485 were used to inhibit or activate the mTOR/P70S6K pathway, respectively. Next, MTT, Transwell, and wound healing assays were employed to assess proliferation and migration of VSMCs. In addition, Western blotting was used to evaluate protein levels of α-SMA, calponin, osteopontin, mTOR, p-mTOR, P70S6K and p-P70S6K in VSMCs. VSMCs showed phenotypic alteration from differentiated to dedifferentiated cells in response to PDGF-BB. MTT, Transwell and wound healing assays showed that FA markedly inhibited proliferation and migration in PDGF-BB-induced VSMCs, in a time and concentration-dependent manner. FA treatment increased the expression levels of the contractile phenotype marker proteins α-SMA and calponin compared with VSMCs stimulated by PDGF-BB alone. Furthermore, FA significantly suppressed mTOR and P70S6K phosphorylation compared with PDGF-BB alone. Similar to FA, downregulation of mTOR signaling by rapamycin inhibited VSMC dedifferentiation. In contrast, upregulation of mTOR signaling by MHY-1485 reversed the FA-induced inhibition of VSMC dedifferentiation. Folic acid inhibits dedifferentiation of PDGF-BB-induced VSMCs by suppressing mTOR/P70S6K signaling.

  17. Inhibiting oncogenic signaling by sorafenib activates PUMA via GSK3β and NF-κB to suppress tumor cell growth

    Science.gov (United States)

    Dudgeon, Crissy; Peng, Rui; Wang, Peng; Sebastiani, Andrea; Yu, Jian; Zhang, Lin

    2011-01-01

    Aberrant Ras/Raf/MEK/ERK signaling is one of the most prevalent oncogenic alterations and confers survival advantage to tumor cells. Inhibition of this pathway can effectively suppress tumor cell growth. For example, sorafenib, a multi-kinase inhibitor targeting c-Raf and other oncogenic kinases, has been used clinically for treating advanced liver and kidney tumors, and also has shown efficacy against other malignancies. However, how inhibition of oncogenic signaling by sorafenib and other drugs suppresses tumor cell growth remains unclear. In this study, we found that sorafenib kills cancer cells by activating PUMA, a p53 target and a BH3-only Bcl-2 family protein. Sorafenib treatment induces PUMA in a variety of cancer cells irrespective of their p53 status. Surprisingly, the induction of PUMA by sorafenib is mediated by IκB-independent activation of NF-κB, which directly binds to the PUMA promoter to activate its transcription. NF-κB activation by sorafenib requires GSK3β activation, subsequent to ERK inhibition. Deficiency in PUMA abrogates sorafenib-induced apoptosis and caspase activation, and renders sorafenib resistance in colony formation and xenograft tumor assays. Furthermore, the chemosensitization effect of sorafenib is dependent on PUMA, and involves concurrent PUMA induction through different pathways. BH3 mimetics potentiate the anticancer effects of sorafenib, and restore sorafenib sensitivity in resistant cells. Together, these results demonstrate a key role of PUMA-dependent apoptosis in therapeutic inhibition of Ras/Raf/MEK/ERK signaling. They provide a rationale for manipulating the apoptotic machinery to improve sensitivity and overcome resistance to the therapies that target oncogenic kinase signaling. PMID:22286758

  18. Testosterone suppresses uropathogenic Escherichia coli invasion and colonization within prostate cells and inhibits inflammatory responses through JAK/STAT-1 signaling pathway.

    Science.gov (United States)

    Ho, Chen-Hsun; Fan, Chia-Kwung; Yu, Hong-Jeng; Wu, Chia-Chang; Chen, Kuan-Chou; Liu, Shih-Ping; Cheng, Po-Ching

    2017-01-01

    Prostatitis is a common condition in adult men of all ages. Uropathogenic Escherichia coli (UPEC) are most frequent pathogen involved in bacterial prostatitis by refluxing the infected urine into prostatic ducts and resulting in an ascending urethral infection. However, the study about the mechanisms of UPEC to invade, replicate and persist in normal prostate epithelial cell is only few. Given the fact that UPEC is pathogen most frequently involved in prostatitis and that testosterone has been demonstrated to attenuate prostate inflammation caused by other etiologies. In this study we investigated whether the testosterone reduces the prostatitis and related mechanism by regulating IFN-γ/STAT1 signaling pathway. In the current study aimed to clarify whether testosterone influences the process of UPEC-induced prostate inflammation and invasion into the prostate epithelial cells. In addition, we set up a normal prostate cell model for UPEC infection to evaluate the ability to invade the urothelial cells as well as the colonization of intercellular bacterial communities in vitro. By using the model, we examine the effects of testosterone to suppress effectively the invasion and survival of UPEC in the prostate cells, and inhibit LPS-induced inflammatory responses through the JAK/STAT1 pathway have also been indicated. Our results demonstrated testosterone not only suppressed the invasion and colonization of UPEC, but also inhibited the expression of pro-inflammatory IL-1β, IL-6 and IL-8 cytokines expression induced by UPEC in a dose-dependent manner. We found the effective dose of testosterone to suppress UPEC infect prostate cells may be appropriate under 40μg/ml. Our data also revealed 20μg/ml testosterone treated PZ-HPV-7 cells significantly suppressed the LPS-induced JAK/STAT1 pathway and inflammatory responses, and reached to maximal effects at 40μg/ml treatment. These results indicate that testosterone plays an anti-inflammatory role in LPS-induced prostate

  19. Sinulariolide Suppresses Human Hepatocellular Carcinoma Cell Migration and Invasion by Inhibiting Matrix Metalloproteinase-2/-9 through MAPKs and PI3K/Akt Signaling Pathways

    Science.gov (United States)

    Wu, Yu-Jen; Neoh, Choo-Aun; Tsao, Chia-Yu; Su, Jui-Hsin; Li, Hsing-Hui

    2015-01-01

    Sinulariolide is an active compound isolated from the cultured soft coral Sinularia flexibilis. In this study, we investigate the migration and invasion effects of sinulariolide in hepatocellular carcinoma cell HA22T. Sinulariolide inhibited the migration and invasion effects of hepatocellular carcinoma cells in a concentration-dependent manner. The results of zymography assay showed that sinulariolide suppressed the activities of matrix metalloproteinase (MMP)-2 and MMP-9. Moreover, protein levels of MMP-2, MMP-9, and urokinase-type plasminogen activator (uPA) were reduced by sinulariolide in a concentration-dependent manner. Sinulariolide also exerted an inhibitory effect on phosphorylation of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinases (ERK), phosphatidylinositol 3-kinase (PI3K), Akt, Focal adhesion kinase (FAK), growth factor receptor-bound protein 2 (GRB2). Taken together, these results demonstrated that sinulariolide could inhibit hepatocellular carcinoma cell migration and invasion and alter HA22T cell metastasis by reduction of MMP-2, MMP-9, and uPA expression through the suppression of MAPKs, PI3K/Akt, and the FAK/GRB2 signaling pathway. These findings suggest that sinulariolide merits further evaluation as a chemotherapeutic agent for human hepatocellular carcinoma. PMID:26204832

  20. Arctigenin inhibits lipopolysaccharide-induced iNOS expression in RAW264.7 cells through suppressing JAK-STAT signal pathway.

    Science.gov (United States)

    Kou, Xianjuan; Qi, Shimei; Dai, Wuxing; Luo, Lan; Yin, Zhimin

    2011-08-01

    Arctigenin has been demonstrated to have an anti-inflammatory function, but the precise mechanisms of its action remain to be fully defined. In the present study, we determined the effects of arctigenin on lipopolysaccharide (LPS)-induced production of proinflammatory mediators and the underlying mechanisms involved in RAW264.7 cells. Our results indicated that arctigenin exerted its anti-inflammatory effect by inhibiting ROS-dependent STAT signaling through its antioxidant activity. Arctigenin also significantly reduced the phosphorylation of STAT1 and STAT 3 as well as JAK2 in LPS-stimulated RAW264.7 cells. The inhibitions of STAT1 and STAT 3 by arctigenin prevented their translocation to the nucleus and consequently inhibited expression of iNOS, thereby suppressing the expression of inflammation-associated genes, such as IL-1β, IL-6 and MCP-1, whose promoters contain STAT-binding elements. However, COX-2 expression was slightly inhibited at higher drug concentrations (50 μM). Our data demonstrate that arctigenin inhibits iNOS expression via suppressing JAK-STAT signaling pathway in macrophages. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

  1. Baicalein attenuates inflammatory responses by suppressing TLR4 mediated NF-κB and MAPK signaling pathways in LPS-induced mastitis in mice.

    Science.gov (United States)

    He, Xuexiu; Wei, Zhengkai; Zhou, Ershun; Chen, Libin; Kou, Jinhua; Wang, Jingjing; Yang, Zhengtao

    2015-09-01

    Baicalein is a phenolic flavonoid presented in the dry roots of Scutellaria baicalensis Georgi. It has been reported that baicalein possesses a number of biological properties, such as antiviral, antioxidative, anti-inflammatory, antithrombotic, and anticancer properties. However, the effect of baicalein on mastitis has not yet been reported. This research aims to detect the effect of baicalein on lipopolysaccharide (LPS)-induced mastitis in mice and to investigate the molecular mechanisms. Baicalein was administered intraperitoneally 1h before and 12h after LPS treatment. The results indicated that baicalein treatment markedly attenuated the damage of the mammary gland induced by LPS, suppressed the activity of myeloperoxidase (MPO) and the levels of tumor necrosis factor (TNF-α) and interleukin (IL-1β) in mice with LPS-induced mastitis. Besides, baicalein blocked the expression of Toll-like receptor 4 (TLR4) and then suppressed the phosphorylation of nuclear transcription factor-kappaB (NF-κB) p65 and degradation inhibitor of NF-κBα (IκBα) and, and inhibited the phosphorylation of p38, extracellular signal-regulated kinase (ERK) and c-jun NH2-terminal kinase (JNK) in mitogen-activated protein kinase (MAPK) signal pathway. These findings suggested that baicalein may have a potential prospect against mastitis. Copyright © 2015. Published by Elsevier B.V.

  2. Diffusion weighted whole body imaging with background body signal suppression (DWIBS). Technical improvement using free breathing, STIR and high resolution 3D display

    International Nuclear Information System (INIS)

    Takahara, Taro; Imai, Yutaka; Yamashita, Tomohiro; Yasuda, Seiei; Nasu, Seiji; Cauteren, M. Van

    2004-01-01

    The purpose of this study was to examine a new way of body diffusion weighted imaging (DWI) using the short TI inversion recovery-echo planar imaging (STIR-EPI) sequence and free breathing scanning (diffusion weighted whole body imaging with background body signal suppression; DWIBS) to obtain three-dimensional displays. Apparent contrast-to-noise ratios (AppCNR) between lymph nodes and surrounding fat tissue were compared in three types of DWI with and without breath-holding, with variable lengths of scan time and slice thickness. The STIR-EPI sequence and spin echo-echo planar imaging (SE-EPI) sequence with chemical shift selective (CHESS) pulse were compared in terms of their degree of fat suppression. Eleven patients with neck, chest, and abdominal malignancy were scanned with DWIBS for evaluation of feasibility. Whole body imaging was done in a later stage of the study using the peripheral vascular coil. The AppCNR of 8 mm slice thickness images reconstructed from 4 mm slice thickness source images obtained in a free breathing scan of 430 sec were much better than 9 mm slice thickness breath-hold scans obtained in 25 sec. High resolution multi-planar reformat (MPR) and maximum intensity projection (MIP) images could be made from the data set of 4 mm slice thickness images. Fat suppression was much better in the STIR-EPI sequence than SE-EPI with CHESS pulse. The feasibility of DWIBS was showed in clinical scans of 11 patients. Whole body images were successfully obtained with adequate fat suppression. Three-dimensional DWIBS can be obtained with this technique, which may allow us to screen for malignancies in the whole body. (author)

  3. Stress and glucocorticoids impair memory retrieval via β2-adrenergic, Gi/o-coupled suppression of cAMP signaling.

    Science.gov (United States)

    Schutsky, Keith; Ouyang, Ming; Castelino, Christina B; Zhang, Lei; Thomas, Steven A

    2011-10-05

    Acute stress impairs the retrieval of hippocampus-dependent memory, and this effect is mimicked by exogenous administration of stress-responsive glucocorticoid hormones. It has been proposed that glucocorticoids affect memory by promoting the release and/or blocking the reuptake of norepinephrine (NE), a stress-responsive neurotransmitter. It has also been proposed that this enhanced NE signaling impairs memory retrieval by stimulating β(1)-adrenergic receptors and elevating levels of cAMP. In contrast, other evidence indicates that NE, β(1), and cAMP signaling is transiently required for the retrieval of hippocampus-dependent memory. To resolve this discrepancy, wild-type rats and mice with and without gene-targeted mutations were stressed or treated with glucocorticoids and/or adrenergic receptor drugs before testing memory for inhibitory avoidance or fear conditioning. Here we report that glucocorticoids do not require NE to impair retrieval. However, stress- and glucocorticoid-induced impairments of retrieval depend on the activation of β(2) (but not β(1))-adrenergic receptors. Offering an explanation for the opposing functions of these two receptors, the impairing effects of stress, glucocorticoids and β(2) agonists on retrieval are blocked by pertussis toxin, which inactivates signaling by G(i/o)-coupled receptors. In hippocampal slices, β(2) signaling decreases cAMP levels and greatly reduces the increase in cAMP mediated by β(1) signaling. Finally, augmenting cAMP signaling in the hippocampus prevents the impairment of retrieval by systemic β(2) agonists or glucocorticoids. These results demonstrate that the β(2) receptor can be a critical effector of acute stress, and that β(1) and β(2) receptors can have quite distinct roles in CNS signaling and cognition.

  4. Klotho-beta overexpression as a novel target for suppressing proliferation and fibroblast growth factor receptor-4 signaling in hepatocellular carcinoma

    Directory of Open Access Journals (Sweden)

    Poh Weijie

    2012-03-01

    Full Text Available Abstract Background We had previously demonstrated overexpression of fibroblast growth factor receptor-4 (FGFR4 in hepatocellular carcinoma (HCC. However, additional molecular mechanisms resulting in amplified FGFR4 signaling in HCC remain under-studied. Here, we studied the mechanistic role of its co-receptor klotho-beta (KLB in driving elevated FGFR4 activity in HCC progression. Results Quantitative real-time PCR analysis identified frequent elevation of KLB gene expression in HCC tumors relative to matched non-tumor tissue, with a more than two-fold increase correlating with development of multiple tumors in patients. KLB-silencing in Huh7 cells decreased cell proliferation and suppressed FGFR4 downstream signaling. While transient repression of KLB-FGFR4 signaling decreased protein expression of alpha-fetoprotein (AFP, a HCC diagnostic marker, prolonged inhibition enriched for resistant HCC cells exhibiting increased liver stemness. Conclusions Elevated KLB expression in HCC tissues provides further credence to the oncogenic role of increased FGFR4 signaling in HCC progression and represents a novel biomarker to identify additional patients amenable to anti-FGFR4 therapy. The restricted tissue expression profile of KLB, together with the anti-proliferative effect observed with KLB-silencing, also qualifies it as a specific and potent therapeutic target for HCC patients. The enrichment of a liver stem cell-like population in response to extended KLB-FGFR4 repression necessitates further investigation to target the development of drug resistance.

  5. Polydatin inhibits cell proliferation and induces apoptosis in laryngeal cancer and HeLa cells via suppression of the PDGF/AKT signaling pathway.

    Science.gov (United States)

    Li, Haixia; Shi, Baoyuan; Li, Yanyun; Yin, Fengfang

    2017-07-01

    Polydatin (PD), a stilbene compound extracted from Polygonum cuspidatum, is suggested to possess anti-cancer activities, including inhibition of cell proliferation, cell cycle arrest, and induction of apoptosis. The platelet-derived growth factor (PDGF)/AKT signaling pathway plays complex roles in tumor suppression. However, the effect of PD on the PDGF/AKT signaling pathway in laryngeal cancer and HeLa cells has not been explored. MTT assay and flow cytometry showed that PD inhibited cell proliferation and induced apoptosis in Hep-2 and AMC-HN-8 cells. Western blot analysis indicated that PD inhibited the expression levels of PDGF-B and phosphorylated AKT (p-AKT) in both cells. Treatment of PDGF-B siRNA or PDGFR inhibitor found that after the PDGF signaling was inactivated, p-AKT expression was significantly decreased in Hep-2 cells. Tumor xenograft experiment in nude mice indicated PD significantly inhibited the growth of Hep-2 cells in vivo. In conclusion, PD inhibited cell proliferation and induced apoptosis in laryngeal cancer and HeLa cells via inactivation of the PDGF/AKT signaling pathway. © 2017 Wiley Periodicals, Inc.

  6. Ovatodiolide Targets β-Catenin Signaling in Suppressing Tumorigenesis and Overcoming Drug Resistance in Renal Cell Carcinoma

    Directory of Open Access Journals (Sweden)

    Jar-Yi Ho

    2013-01-01

    Full Text Available Dysregulated β-catenin signaling is intricately involved in renal cell carcinoma (RCC carcinogenesis and progression. Determining potential β-catenin signaling inhibitors would be helpful in ameliorating drug resistance in advanced or metastatic RCC. Screening for β-catenin signaling inhibitors involved in silico inquiry of the PubChem Bioactivity database followed by TCF/LEF reporter assay. The biological effects of ovatodiolide were evaluated in 4 RCC cell lines in vitro and 2 RCC cell lines in a mouse xenograft model. The synergistic effects of ovatodiolide and sorafenib or sunitinib were examined in 2 TKI-resistant RCC cell lines. Ovatodiolide, a pure compound of Anisomeles indica, inhibited β-catenin signaling and reduced RCC cell viability, survival, migration/invasion, and in vitro cell or in vivo mouse tumorigenicity. Cytotoxicity was significantly reduced in a normal kidney epithelial cell line with the treatment. Ovatodiolide reduced phosphorylated β-catenin (S552 that inhibited β-catenin nuclear translocation. Moreover, ovatodiolide decreased β-catenin stability and impaired the association of β-catenin and transcription factor 4. Ovatodiolide combined with sorafenib or sunitinib overcame drug resistance in TKI-resistant RCC cells. Ovatodiolide may be a potent β-catenin signaling inhibitor, with synergistic effects with sorafenib or sunitinib, and therefore, a useful candidate for improving RCC therapy.

  7. Arctigenin Suppress Th17 Cells and Ameliorates Experimental Autoimmune Encephalomyelitis Through AMPK and PPAR-γ/ROR-γt Signaling.

    Science.gov (United States)

    Li, Wen; Zhang, Zhihui; Zhang, Kai; Xue, Zhenyi; Li, Yan; Zhang, Zimu; Zhang, Lijuan; Gu, Chao; Zhang, Qi; Hao, Junwei; Da, Yurong; Yao, Zhi; Kong, Ying; Zhang, Rongxin

    2016-10-01

    Arctigenin is a herb compound extract from Arctium lappa and is reported to exhibit pharmacological properties, including neuronal protection and antidiabetic, antitumor, and antioxidant properties. However, the effects of arctigenin on autoimmune inflammatory diseases of the CNS, multiple sclerosis (MS), and its animal model experimental autoimmune encephalomyelitis (EAE) are still unclear. In this study, we demonstrated that arctigenin-treated mice are resistant to EAE; the clinical scores of arctigenin-treated mice are significantly reduced. Histochemical assays of spinal cord sections also showed that arctigenin reduces inflammation and demyelination in mice with EAE. Furthermore, the Th1 and Th17 cells in peripheral immune organs are inhibited by arctigenin in vivo. In addition, the Th1 cytokine IFN-γ and transcription factor T-bet, as well as the Th17 cytokines IL-17A, IL-17F, and transcription factor ROR-γt are significantly suppressed upon arctigenin treatment in vitro and in vivo. Interestedly, Th17 cells are obviously inhibited in CNS of mice with EAE, while Th1 cells do not significantly change. Besides, arctigenin significantly restrains the differentiation of Th17 cells. We further demonstrate that arctigenin activates AMPK and inhibits phosphorylated p38, in addition, upregulates PPAR-γ, and finally suppresses ROR-γt. These findings suggest that arctigenin may have anti-inflammatory and immunosuppressive properties via inhibiting Th17 cells, indicating that it could be a potential therapeutic drug for multiple sclerosis or other autoimmune inflammatory diseases.

  8. Developmental exposure of aflatoxin B1 reversibly affects hippocampal neurogenesis targeting late-stage neural progenitor cells through suppression of cholinergic signaling in rats

    International Nuclear Information System (INIS)

    Tanaka, Takeshi; Mizukami, Sayaka; Hasegawa-Baba, Yasuko; Onda, Nobuhiko; Sugita-Konishi, Yoshiko; Yoshida, Toshinori; Shibutani, Makoto

    2015-01-01

    Highlights: • Maternal AFB 1 exposure effect on hippocampal neurogenesis was examined in rats. • AFB 1 reversibly reduced cell proliferation and type-3 progenitor cells in the SGZ. • Suppressed cholinergic signals to GABAergic interneurons may reduce type-3 cells. • Suppressed BDNF–TRKB signaling may contribute to aberration of neurogenesis. • The NOAEL for offspring was determined to be 0.1 ppm (7.1–13.6 μg/kg BW/day). - Abstract: To elucidate the maternal exposure effects of aflatoxin B 1 (AFB 1 ) and its metabolite aflatoxin M 1 , which is transferred into milk, on postnatal hippocampal neurogenesis, pregnant Sprague-Dawley rats were provided a diet containing AFB 1 at 0, 0.1, 0.3, or 1.0 ppm from gestational day 6 to day 21 after delivery on weaning. Offspring were maintained through postnatal day (PND) 77 without AFB 1 exposure. Following exposure to 1.0 ppm AFB 1 , offspring showed no apparent systemic toxicity at weaning, whereas dams showed increased liver weight and DNA repair gene upregulation in the liver. In the hippocampal dentate gyrus of male PND 21 offspring, the number of doublecortin + progenitor cells were decreased, which was associated with decreased proliferative cell population in the subgranular zone at ≥0.3 ppm, although T-box brain 2 + cells, tubulin beta III + cells, gamma-H2A histone family, member X + cells, and cyclin-dependent kinase inhibitor 1A + cells did not fluctuate in number. AFB 1 exposure examined at 1.0 ppm also resulted in transcript downregulation of the cholinergic receptor subunit Chrna7 and dopaminergic receptor Drd2 in the dentate gyrus, although there was no change in transcript levels of DNA repair genes. In the hippocampal dentate hilus, interneurons expressing CHRNA7 or phosphorylated tropomyosin receptor kinase B (TRKB) decreased at ≥0.3 ppm. On PND 77, there were no changes in neurogenesis-related parameters. These results suggested that maternal AFB 1 exposure reversibly affects hippocampal

  9. Suppression of Wnt signaling by the miR-29 family is mediated by demethylation of WIF-1 in non-small-cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Min [Department of Respiratory Medicine, Shanghai Tenth People’s Hospital, Tongji University, Shanghai 200072 (China); Wu, Junjie, E-mail: wujunjiesh@126.com [Department of Pneumology, Changhai Hospital of Shanghai, Second Military Medical University, Shanghai 200433 (China); State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai 200433 (China); Cai, Yong, E-mail: dryongcai@126.com [Department of Radiation Oncology, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433 (China)

    2013-09-06

    Highlights: •Dnmt3A and Dnmt3B are involved in the down-regulation of WIF-1 expression in non-small-cell lung cancer. •MiR-29 family members could restore WIF-1 expression through demethylation. •MiR-29s suppress Wnt/β-catenin signaling pathway and inhibit tumor growth. •The expression of miR-29a and miR-29b could be regulated partially in a positive feedback loop. -- Abstract: Wnt inhibitory factor-1 (WIF-1) silencing induced by promoter hypermethylation is a common mechanism of aberrant activation of the Wnt signaling pathway in non-small-cell lung cancer (NSCLC). However, the activity of regulators associated with the methylation of the WIF-1 gene remains unclear. Here, we investigated the role of three DNA methyltransferases (DNMT1, DNMT3A and DNMT3B) in the expression of WIF-1. The three DNMTs were up-regulated in NSCLC tumor tissues and suppression of DNMT3A and DNMT3B restored the expression of WIF-1 in NSCLC cells. The miR-29 family (miR-29a, -29b, and -29c), which negatively regulates DNMT3A and DNMT3B, was examined in association with the Wnt/β-catenin signaling pathway. A positive correlation between the expression of WIF-1 and that of MiR-29s was observed in NSCLC tissues. Methylation-specific PCR and Western blotting indicated that miR-29s positively regulate WIF-1 expression by inhibiting the methylation of its promoter. Furthermore, miR-29 overexpression downregulated β-catenin expression, inhibited cell proliferation and induced apoptosis. The expression of miR-29a and miR-29b was partially regulated by DNMT3A and DNMT3B in a positive feedback loop. Taken together, our findings show that miR-29s suppress the Wnt signaling pathway through demethylation of WIF-1 in NSCLC.

  10. Fetal ECG Extraction from Abdominal Signals: A Review on Suppression of Fundamental Power Line Interference Component and Its Harmonics

    Directory of Open Access Journals (Sweden)

    Dragoş-Daniel Ţarălungă

    2014-01-01

    Full Text Available Interference of power line (PLI (fundamental frequency and its harmonics is usually present in biopotential measurements. Despite all countermeasures, the PLI still corrupts physiological signals, for example, electromyograms (EMG, electroencephalograms (EEG, and electrocardiograms (ECG. When analyzing the fetal ECG (fECG recorded on the maternal abdomen, the PLI represents a particular strong noise component, being sometimes 10 times greater than the fECG signal, and thus impairing the extraction of any useful information regarding the fetal health state. Many signal processing methods for cancelling the PLI from biopotentials are available in the literature. In this review study, six different principles are analyzed and discussed, and their performance is evaluated on simulated data (three different scenarios, based on five quantitative performance indices.

  11. Ethanol Inhibits High-Affinity Immunoglobulin E Receptor (FcεRI) Signaling in Mast Cells by Suppressing the Function of FcεRI-Cholesterol Signalosome

    Science.gov (United States)

    Draberova, Lubica; Paulenda, Tomas; Halova, Ivana; Potuckova, Lucie; Bugajev, Viktor; Bambouskova, Monika; Tumova, Magda; Draber, Petr

    2015-01-01

    Ethanol has multiple effects on biochemical events in a variety of cell types, including the high-affinity immunoglobulin E receptor (FcεRI) signaling in antigen-activated mast cells. However, the underlying molecular mechanism remains unknown. To get better understanding of the effect of ethanol on FcεRI-mediated signaling we examined the effect of short-term treatment with non-toxic concentrations of ethanol on FcεRI signaling events in mouse bone marrow-derived mast cells. We found that 15 min exposure to ethanol inhibited antigen-induced degranulation, calcium mobilization, expression of proinflammatory cytokine genes (tumor necrosis factor-α, interleukin-6, and interleukin-13), and formation of reactive oxygen species in a dose-dependent manner. Removal of cellular cholesterol with methyl-β-cyclodextrin had a similar effect and potentiated some of the inhibitory effects of ethanol. In contrast, exposure of the cells to cholesterol-saturated methyl-β-cyclodextrin abolished in part the inhibitory effect of ethanol on calcium response and production of reactive oxygen species, supporting lipid-centric theories of ethanol action on the earliest stages of mast cell signaling. Further studies showed that exposure to ethanol and/or removal of cholesterol inhibited early FcεRI activation events, including tyrosine phosphorylation of the FcεRI β and γ subunits, SYK kinases, LAT adaptor protein, phospholipase Cγ, STAT5, and AKT and internalization of aggregated FcεRI. Interestingly, ethanol alone, and particularly in combination with methyl-β-cyclodextrin, enhanced phosphorylation of negative regulatory tyrosine 507 of LYN kinase. Finally, we found that ethanol reduced passive cutaneous anaphylactic reaction in mice, suggesting that ethanol also inhibits FcεRI signaling under in vivo conditions. The combined data indicate that ethanol interferes with early antigen-induced signaling events in mast cells by suppressing the function of Fc

  12. Morin ameliorates chemically induced liver fibrosis in vivo and inhibits stellate cell proliferation in vitro by suppressing Wnt/β-catenin signaling

    Energy Technology Data Exchange (ETDEWEB)

    MadanKumar, Perumal; NaveenKumar, Perumal; Manikandan, Samidurai [Department of Biochemistry, University of Madras, Guindy Campus, Chennai 600 025, Tamil Nadu (India); Devaraj, Halagowder [Department of Zoology, University of Madras, Guindy Campus, Chennai 600 025, Tamil Nadu (India); NiranjaliDevaraj, Sivasithamparam, E-mail: niranjali@yahoo.com [Department of Biochemistry, University of Madras, Guindy Campus, Chennai 600 025, Tamil Nadu (India)

    2014-06-01

    The anti-fibrotic effect of morin was examined in LX-2 cells (culture-activated human hepatic stellate cells) and in diethylnitrosamine induced rat model of liver fibrosis. The in vitro study was designed to determine whether morin affects the survival of cultured LX-2 cells, while the in vivo study was designed to evaluate the antioxidant and anti-fibrotic efficacy of morin on diethylnitrosamine induced liver fibrosis in male albino Wistar rat. The activities of liver function enzymes in serum, liver lipid peroxide levels, activities of serum antioxidant enzymes and liver architecture were monitored to cast light on the antioxidant and hepatoprotective nature of morin. To establish the anti-fibrotic effects of morin, the levels of key Wnt signaling molecules which are strongly associated with the signal transduction pathway of HSC activation were measured. Overall, from the in vitro results, it was observed that morin at 50 μM concentration inhibited the proliferation of cultured LX-2 cells, inhibited Wnt signaling and induced G1 cell cycle arrest. The in vivo results further confirmed that morin by downregulating the expressions of GSK-3β, β-catenin and cyclin D1 ameliorated DEN-induced liver fibrosis. Hence morin could be employed as a promising chemopreventive natural supplement for liver fibrosis. - Highlights: • In vivo and in vitro results revealed the active participation of Wnt signaling. • Morin at 50 μM inhibited LX-2 cell proliferation by suppressing Wnt signaling. • Morin exhibited hepatoprotective effects against DEN induced liver fibrosis. • Morin inhibited HSC activation in vivo by downregulating Wnt/β-catenin signaling.

  13. Special regulatory T-cell review: FOXP3 biochemistry in regulatory T cells – how diverse signals regulate suppression

    Science.gov (United States)

    Li, Bin; Greene, Mark I

    2008-01-01

    FOXP3 is an acetylated and phosphorylated protein active in human regulatory T cells and forms oligomers which then associate with an even larger molecular complex. FOXP3 actively regulates transcription by recruiting enzymatic co-repressors and/or co-activators. FOXP3 complex ensembles are dynamically regulated by physiological stimuli such as T-cell receptor, IL-2 and proinflammation cytokine signals. Understanding the post-translational modifications of FOXP3 regulated by diverse signals and the biochemistry and structural chemistry of enzymatic proteins in the FOXP3 complex is critical for therapeutically modulating regulatory T cell function. PMID:18154614

  14. c-Ski inhibits the proliferation of vascular smooth muscle cells via suppressing Smad3 signaling but stimulating p38 pathway.

    Science.gov (United States)

    Li, Jun; Li, Ping; Zhang, Yan; Li, Gong-Bo; Zhou, Yuan-Guo; Yang, Kang; Dai, Shuang-Shuang

    2013-01-01

    Proliferation of vascular smooth muscle cells (VSMCs) plays key roles in the progression of intimal hyperplasia, but the molecular mechanisms that trigger VSMC proliferation after vascular injury remain unclear. c-Ski, a co-repressor of transforming growth factor β (TGF-β)/Smad signaling, was detected to express in VSMC of rat artery. During the course of arterial VSMC proliferation induced by balloon injury in rat, the endogenous protein expressions of c-Ski decreased markedly in a time-dependent manner. In vivo c-Ski gene delivery was found to significantly suppress balloon injury-induced VSMC proliferation and neointima formation. Further investigation in A10 rat aortic smooth muscle cells demonstrated that overexpression of c-Ski gene inhibited TGF-β1 (1 ng/ml)-induced A10 cell proliferation while knockdown of c-Ski by RNAi enhanced the stimulatory effect of TGF-β1 on A10 cell growth. Western blot for signaling detection showed that suppression of Smad3 phosphorylation while stimulating p38 signaling associated with upregulation of cyclin-dependent kinase inhibitors p21 and p27 was responsible for the inhibitory effect of c-Ski on TGF-β1-induced VSMC proliferation. These data suggest that the decrease of endogenous c-Ski expression is implicated in the progression of VSMC proliferation after arterial injury and c-Ski administration represents a promising role for treating intimal hyperplasia via inhibiting the proliferation of VSMC. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. Long-Term Expansion, Enhanced Chondrogenic Potential, and Suppression of Endochondral Ossification of Adult Human MSCs via WNT Signaling Modulation

    Directory of Open Access Journals (Sweden)

    Roberto Narcisi

    2015-03-01

    Full Text Available Mesenchymal stem cells (MSCs are a potential source of chondrogenic cells for the treatment of cartilage disorders, but loss of chondrogenic potential during in vitro expansion and the propensity of cartilage to undergo hypertrophic maturation impede their therapeutic application. Here we report that the signaling protein WNT3A, in combination with FGF2, supports long-term expansion of human bone marrow-derived MSCs. The cells retained their chondrogenic potential and other phenotypic and functional properties of multipotent MSCs, which were gradually lost in the absence of WNT3A. Moreover, we discovered that endogenous WNT signals are the main drivers of the hypertrophic maturation that follows chondrogenic differentiation. Inhibition of WNT signals during differentiation prevented calcification and maintained cartilage properties following implantation in a mouse model. By maintaining potency during expansion and preventing hypertrophic maturation following differentiation, the modulation of WNT signaling removes two major obstacles that impede the clinical application of MSCs in cartilage repair.

  16. Bone morphogenetic protein-9 suppresses growth of myeloma cells by signaling through ALK2 but is inhibited by endoglin

    DEFF Research Database (Denmark)

    Olsen, O E; Wader, K F; Misund, K

    2014-01-01

    myeloma cell samples by signaling through ALK2. BMP-9-induced apoptosis in myeloma cells was associated with c-MYC downregulation. The effects of BMP-9 were counteracted by membrane-bound (CD105) or soluble endoglin present in the bone marrow microenvironment, suggesting a mechanism for how myeloma cells...

  17. Light-load resistance exercise increases muscle protein synthesis and hypertrophy signaling in elderly men

    DEFF Research Database (Denmark)

    Agergaard, Jakob; Bülow, Jacob; Jensen, Jacob K

    2017-01-01

    INTRODUCTION: The present study investigated whether well-tolerated light-load resistance exercise (LL-RE) affects skeletal muscle fractional synthetic rate (FSR) and anabolic intracellular signaling as a way to counteract age-related loss of muscle mass. METHODS: Untrained healthy men (age: +65...... and 12g whey protein at 7 hours post-exercise; N=10) or placebo (4g maltodextrin/hour; N=10). Quadriceps muscle biopsies were taken at 0, 3, 7 and 10 hours post-exercise from both the resting and exercised leg. Myofibrillar-FSR and activity of select targets from the mTORC1-signalling cascade were...

  18. miR-124 suppresses proliferation and invasion of nasopharyngeal carcinoma cells through the Wnt/β-catenin signaling pathway by targeting Capn4

    Directory of Open Access Journals (Sweden)

    Hu H

    2017-05-01

    Full Text Available Haili Hu,1,* Guanghui Wang,1,* Congying Li2 1Department of Otorhinolaryngology, Huaihe Hospital of Henan University, 2Department of Otorhinolaryngology, School of Medicine, Kaifeng University, Kaifeng, People’s Republic of China *These authors contributed equally to this work Background: Recent studies have demonstrated that microRNA 124 (miR-124 acts as a tumor suppressor in nasopharyngeal carcinoma (NPC; however, the exact molecular mechanism by which miR-124 exerts tumor suppression has not been well elucidated.Materials and methods: We performed quantitative real-time PCR (qRT-PCR to measure the expression of metastasis associated lung adenocarcinoma transcript 1, miR-124, and calpain small subunit 1 (Capn4 mRNAs in NPC cell lines. We also performed western blot analysis to detect the levels of Capn4. Furthermore, we performed MTT assay and transwell invasion assay to determine the proliferation and invasion ability of two NPC cell lines, namely, HONE1 and CNE2 cells, respectively. The verification of targets of miR-124 was performed using prediction softwares and luciferase reporter analysis.Results: According to our results, the expression of Capn4 was found to be elevated, whereas the expression of miR-124 was lowered in NPC cell lines compared with normal nasopharyngeal cells. When we preformed overexpression of miR-124, it suppressed the proliferation and invasion of NPC cells. Moreover, miR-124 suppressed the expression of Capn4 by targeting Capn4 in HONE1 and CNE2 cells. When we preformed overexpression of Capn4, it reversed the inhibitory effect of miR-124 on the proliferation and invasion of NPC cells. Furthermore, miR-124–Capn4 axis decreased the levels of β-catenin, cyclin D1, and c-Myc, the components of the Wnt/β-catenin signaling pathway.Conclusion: The suppression of proliferation and invasion of NPC cells by miR-124 were achieved by the regulation of Wnt/β-catenin signaling pathway by targeting Capn4. The results of

  19. Oral administration of nano-emulsion curcumin in mice suppresses inflammatory-induced NFκB signaling and macrophage migration.

    Directory of Open Access Journals (Sweden)

    Nicholas A Young

    Full Text Available Despite the widespread use of curcumin for centuries in Eastern medicine as an anti-inflammatory agent, its molecular actions and therapeutic viability have only recently been explored. While curcumin does have potential therapeutic efficacy, both solubility and bioavailability must be improved before it can be more successfully translated to clinical care. We have previously reported a novel formulation of nano-emulsion curcumin (NEC that achieves significantly greater plasma concentrations in mice after oral administration. Here, we confirm the immunosuppressive effects of NEC in vivo and further examine its molecular mechanisms to better understand therapeutic potential. Using transgenic mice harboring an NFκB-luciferase reporter gene, we demonstrate a novel application of this in vivo inflammatory model to test the efficacy of NEC administration by bioluminescent imaging and show that LPS-induced NFκB activity was suppressed with NEC compared to an equivalent amount of curcumin in aqueous suspension. Administration of NEC by oral gavage resulted in a reduction of blood monocytes, decreased levels of both TLR4 and RAGE expression, and inhibited secretion of MCP-1. Mechanistically, curcumin blocked LPS-induced phosphorylation of the p65 subunit of NFκB and IκBα in murine macrophages. In a mouse model of peritonitis, NEC significantly reduced macrophage recruitment, but not T-cell or B-cell levels. In addition, curcumin treatment of monocyte derived cell lines and primary human macrophages in vitro significantly inhibited cell migration. These data demonstrate that curcumin can suppress inflammation by inhibiting macrophage migration via NFκB and MCP-1 inhibition and establish that NEC is an effective therapeutic formulation to increase the bioavailability of curcumin in order to facilitate this response.

  20. Effusanin E suppresses nasopharyngeal carcinoma cell growth by inhibiting NF-κB and COX-2 signaling.

    Directory of Open Access Journals (Sweden)

    Mingzhu Zhuang

    Full Text Available Rabdosia serra is well known for its antibacterial, anti-inflammatory and antitumor activities, but no information has been available for the active compounds derived from this plant in inhibiting human nasopharyngeal carcinoma (NPC cell growth. In this study, we isolated and purified a natural diterpenoid from Rabdosia serra and identified its chemical structure as effusanin E and elucidated its underlying mechanism of action in inhibiting NPC cell growth. Effusanin E significantly inhibited cell proliferation and induced apoptosis in NPC cells. Effusanin E also induced the cleavage of PARP, caspase-3 and -9 proteins and inhibited the nuclear translocation of p65 NF-κB proteins. Moreover, effusanin E abrogated the binding of NF-κB to the COX-2 promoter, thereby inhibiting the expression and promoter activity of COX-2. Pretreatment with a COX-2 or NF-κB-selective inhibitor (celecoxib or ammonium pyrrolidinedithiocarbamate had an additive effect on the effusanin E-mediated inhibition of proliferation, while pretreatment with an activator of NF-κB/COX-2 (lipopolysaccharides abrogated the effusanin E-mediated inhibition of proliferation. Effusanin E also significantly suppressed tumor growth in a xenograft mouse model without obvious toxicity, furthermore, the expression of p50 NF-κB and COX-2 were down-regulated in the tumors of nude mice. These data suggest that effusanin E suppresses p50/p65 proteins to down-regulate COX-2 expression, thereby inhibiting NPC cell growth. Our findings provide new insights into exploring effusanin E as a potential therapeutic compound for the treatment of human nasopharyngeal carcinoma.

  1. Minocycline and fluorocitrate suppress spinal nociceptive signaling in intrathecal IL-1β-induced thermal hyperalgesic rats.

    Science.gov (United States)

    Sung, Chun-Sung; Cherng, Chen-Hwan; Wen, Zhi-Hong; Chang, Wen-Kuei; Huang, Shi-Ying; Lin, Shinn-Long; Chan, Kwok-Hon; Wong, Chih-Shung

    2012-12-01

    We previously demonstrated that intrathecal IL-1β caused thermal hyperalgesia in rats. This study was conducted to examine the effects and cellular mechanisms of glial inhibitors on IL-1β-induced nociception in rats. The effects of minocycline (20 μg), fluorocitrate (1 nmol), and SB203580 (5 μg) on IL-1β (100 ng) treatment in rats were measured by nociceptive behaviors, western blotting of p38 mitogen-activated protein kinase (MAPK) and inducible nitric oxide synthase (iNOS) expression, cerebrospinal fluid nitric oxide (NO) levels, and immunohistochemical analyses. The results demonstrated that intrathecal IL-1β activated microglia and astrocytes, but not neurons, in the dorsal horn of the lumbar spinal cord, as evidenced by morphological changes and increased immunoreactivity, phosphorylated p38 (P-p38) MAPK, and iNOS expression; the activation of microglia and astrocytes peaked at 30 min and lasted for 6 h. The immunoreactivities of microglia and astrocytes were significantly increased at 30 min (6.6- and 2.7-fold, respectively) and 6 h (3.3- and 4.0-fold, respectively) following IL-1β injection, as compared with saline controls at 30 min (all P fluorocitrate, or SB203580 pretreatment suppressed this IL-1β-upregulated P-p38 MAPK mainly in microglia and iNOS mainly in astrocytes; minocycline exhibited the most potent effect. Minocycline and fluorocitrate pretreatment abrogated IL-1β-induced NO release and thermal hyperalgesia in rats. In conclusion, minocycline, fluorocitrate, and SB203580 effectively suppressed the IL-1β-induced central sensitization and hyperalgesia in rats. Copyright © 2012 Wiley Periodicals, Inc.

  2. Effects of sorafenib on energy metabolism in breast cancer cells: role of AMPK-mTORC1 signaling.

    Science.gov (United States)

    Fumarola, Claudia; Caffarra, Cristina; La Monica, Silvia; Galetti, Maricla; Alfieri, Roberta R; Cavazzoni, Andrea; Galvani, Elena; Generali, Daniele; Petronini, Pier Giorgio; Bonelli, Mara A

    2013-08-01

    In this study, we investigated the effects and the underlying molecular mechanisms of the multi-kinase inhibitor sorafenib in a panel of breast cancer cell lines. Sorafenib inhibited cell proliferation and induced apoptosis through the mitochondrial pathway. These effects were neither correlated with modulation of MAPK and AKT pathways nor dependent on the ERα status. Sorafenib promoted an early perturbation of mitochondrial function, inducing a deep depolarization of mitochondrial membrane, associated with drop of intracellular ATP levels and increase of ROS generation. As a response to this stress condition, the energy sensor AMPK was rapidly activated in all the cell lines analyzed. In MCF-7 and SKBR3 cells, AMPK enhanced glucose uptake by up-regulating the expression of GLUT-1 glucose transporter, as also demonstrated by AMPKα1 RNA interference, and stimulated aerobic glycolysis thus increasing lactate production. Moreover, the GLUT-1 inhibitor fasentin blocked sorafenib-induced glucose uptake and potentiated its cytotoxic activity in SKBR3 cells. Persistent activation of AMPK by sorafenib finally led to the impairment of glucose metabolism both in MCF-7 and SKBR3 cells as well as in the highly glycolytic MDA-MB-231 cells, resulting in cell death. This previously unrecognized long-term effect of sorafenib was mediated by AMPK-dependent inhibition of the mTORC1 pathway. Suppression of mTORC1 activity was sufficient for sorafenib to hinder glucose utilization in breast cancer cells, as demonstrated by the observation that the mTORC1 inhibitor rapamycin induced a comparable down-regulation of GLUT-1 expression and glucose uptake. The key role of AMPK-dependent inhibition of mTORC1 in sorafenib mechanisms of action was confirmed by AMPKα1 silencing, which restored mTORC1 activity conferring a significant protection from cell death. This study provides insights into the molecular mechanisms driving sorafenib anti-tumoral activity in breast cancer, and supports

  3. Preclinical evaluation of destruxin B as a novel Wnt signaling target suppressing proliferation and metastasis of colorectal cancer using non-invasive bioluminescence imaging

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, Chi-Tai [Graduate Institute of Clinical Medicine, Taipei Medical University, Taipei, Taiwan (China); Center of Excellence for Cancer Research, Taipei Medical University, Taipei, Taiwan (China); Department of Surgery, Taipei Medical University-Shuang Ho Hospital, Taipei, Taiwan (China); Rao, Yerra Koteswara [Institute of Biochemical Sciences and Technology, Chaoyang University of Technology, Taichung, Taiwan (China); Ye, Min [Department of Natural Medicine, School of Pharmaceutical Sciences, Peking University, Beijing (China); Wu, Wen-Shi [Department of Horticulture and Biotechnology, Chinese Culture University, Taipei, Taiwan (China); Chang, Tung-Chen [Department of Surgery, Taipei Medical University-Shuang Ho Hospital, Taipei, Taiwan (China); Wang, Liang-Shun [Graduate Institute of Clinical Medicine, Taipei Medical University, Taipei, Taiwan (China); Division of Thoracic Surgery, Department of Surgery, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan (China); Wu, Chih-Hsiung [Center of Excellence for Cancer Research, Taipei Medical University, Taipei, Taiwan (China); Department of Surgery, Taipei Medical University-Shuang Ho Hospital, Taipei, Taiwan (China); Wu, Alexander T.H., E-mail: chaw1211@tmu.edu.tw [Ph.D. Program for Translational Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan (China); Department of Radiation Oncology, Taipei Medical University Hospital, Taipei, Taiwan (China); Tzeng, Yew-Min, E-mail: ymtzeng@cyut.edu.tw [Institute of Biochemical Sciences and Technology, Chaoyang University of Technology, Taichung, Taiwan (China)

    2012-05-15

    In continuation to our studies toward the identification of direct anti-cancer targets, here we showed that destruxin B (DB) from Metarhizium anisopliae suppressed the proliferation and induced cell cycle arrest in human colorectal cancer (CRC) HT29, SW480 and HCT116 cells. Additionally, DB induced apoptosis in HT29 cells by decreased expression level of anti-apoptotic proteins Bcl-2 and Bcl-xL while increased pro-apoptotic Bax. On the other hand, DB attenuated Wnt-signaling by downregulation of β-catenin, Tcf4 and β-catenin/Tcf4 transcriptional activity, concomitantly with decreased expression of β-catenin target genes cyclin D1, c-myc and survivin. Furthermore, DB affected the migratory and invasive ability of HT29 cells through suppressed MMPs-2 and -9 enzymatic activities. We also found that DB targeted the MAPK and/or PI3K/Akt pathway by reduced expression of Akt, IKK-α, JNK, NF-κB, c-Jun and c-Fos while increased that of IκBα. Finally, we demonstrated that DB inhibited tumorigenesis in HT29 xenograft mice using non-invasive bioluminescence technique. Consistently, tumor samples from DB-treated mice demonstrated suppressed expression of β-catenin, cyclin D1, survivin, and endothelial marker CD31 while increased caspase-3 expression. Collectively, our data supports DB as an inhibitor of Wnt/β-catenin/Tcf signaling pathway that may be beneficial in the CRC management. Highlights: ► Destruxin B (DB) inhibited colorectal cancer cells growth and induced apoptosis. ► MAPK and/or PI3K/Akt cascade cooperates in DB induced apoptosis. ► DB affected the migratory and invasive ability of HT29 cells through MMP-9. ► DB attenuated Wnt-signaling components β-catenin, Tcf4. ► DB attenuated cyclin D1, c-myc, survivin and tumorigenesis in HT29 xenograft mice.

  4. Diagnosis of complications associated with acute cholecystitis using computed tomography and diffusion-weighted imaging with background body signal suppression/T2 image fusion

    Science.gov (United States)

    Tomizawa, Minoru; Shinozaki, Fuminobu; Tanaka, Satomi; Sunaoshi, Takafumi; Kano, Daisuke; Sugiyama, Eriko; Shite, Misaki; Haga, Ryouta; Fukamizu, Yoshiya; Fujita, Toshiyuki; Kagayama, Satoshi; Hasegawa, Rumiko; Shirai, Yoshinori; Motoyoshi, Yasufumi; Sugiyama, Takao; Yamamoto, Shigenori; Ishige, Naoki

    2017-01-01

    In a clinical setting, it is important to diagnose complications of acute cholecystitis accurately. Diffusion-weighted whole body imaging with background body signal suppression/T2-weighted image fusion (DWIBS/T2) provides high signal intensity with a strong contrast against surrounding tissues in anatomical settings. In the present study, patients who were being treated for acute cholecystitis and underwent DWIBS/T2 in the National Hospital Organization Shimoshizu Hospital between December 2012 and August 2015 were enrolled. A total of 10 men and 4 women underwent DWIBS/T2. Records, including DWIBS/T2 and computed tomography (CT) imaging, were retrospectively analyzed for patients with acute cholecystitis. CT images revealed thickened gallbladder walls in patients with acute cholecystitis, and high signal intensity was observed in DWIBS/T2 images for the thickened gallbladder wall. Inflammation of the pericholecystic space and the liver resulted in high intensity signals with DWIBS/T2 imaging, whereas CT imaging revealed a low-density area in the cholecystic space. Plain CT scanning identified a low-density area in the liver, which became more obvious with contrast-enhanced CT. DWIBS/T2 imaging showed the inflammation of the liver and pericholesyctic space as an area of high signal intensity. Detectability of inflammation of the pericholecystic space and the liver was the same for DWIBS/T2 and CT, which suggests that DWIBS/T2 has the same sensitivity as CT scanning for the diagnosis of complicated acute cholecystitis. However, the strong contrast shown by DWIBS/T2 allows for easier evaluation of acute cholecystitis than CT scanning. PMID:28672993

  5. Study on generation mechanisms of second-order nonlinear signals in surface acoustic wave devices and their suppression

    Science.gov (United States)

    Nakagawa, Ryo; Kyoya, Haruki; Shimizu, Hiroshi; Kihara, Takashi; Hashimoto, Ken-ya

    2015-07-01

    In this study, we examine the generation mechanisms of the second-order nonlinear signals in surface acoustic wave resonators/duplexers fabricated on a 42°YX-LiTaO3 substrate. It is shown that the crystal asymmetry of the substrate can generate the second-order nonlinear signals. The following two mechanisms mainly contribute to their generation: (a) self-mixing of the electrostatic field and (b) mixing of the electrostatic field with the strain field associated with laterally propagating modes. Both of them occur at the gaps between the electrode tip and the dummy electrode. In addition, an interdigital transducer design that cancels this asymmetry is proposed. The design is applied to a one-port resonator and a duplexer, and the effectiveness of this technique is demonstrated.

  6. Lipo-PGE1 suppresses collagen production in human dermal fibroblasts via the ERK/Ets-1 signaling pathway.

    Directory of Open Access Journals (Sweden)

    Yoolhee Yang

    Full Text Available Dysregulation of collagen production contributes to various pathological processes, including tissue fibrosis as well as impaired wound healing. Lipo-prostaglandin E1 (Lipo-PGE1, a lipid microsphere-incorporated prostaglandin E1, is used as a vasodilator for the treatment of peripheral vascular diseases. Lipo-PGE1 was recently shown to enhance human dermal fibroblast (HDF migration and in vivo wound healing. No published study has characterized the role of Lipo-PGE1 in collagen regulation in HDFs. Here, we investigated the cellular signaling mechanism by which Lipo-PGE1 regulates collagen in HDFs. Collagen production was evaluated by the Sircol collagen assay, Western blot analysis of type I collagen and real time PCR. Unexpectedly, Lipo-PGE1 decreased mRNA expression of collagen 1A1, 1A2, and 3A1. Lipo-PGE1 markedly inhibited type I collagen and total soluble collagen production. In addition, Lipo-PGE1 inhibited transforming growth factor-β-induced collagen expression via Smad2 phosphorylation. To further investigate whether extracellular signal-regulated kinase (ERK/Ets-1 signaling, a crucial pathway in collagen regulation, is involved in Lipo-PGE1-inhibited collagen production, cells were pretreated with an ERK-specific inhibitor, PD98059, prior to the addition of Lipo-PGE1. Lipo-PGE1-inhibited collagen mRNA expression and total soluble collagen production were recovered by pretreatment with PD98059. Moreover, Lipo-PGE1 directly induced the phosphorylation of ERK. Furthermore, silencing of Ets-1 recovered Lipo-PGE1-inhibited collagen production and PD98059 blocked Lipo-PGE1-enhanced Ets-1 expression. The present study reveals an important role for Lipo-PGE1 as a negative regulator of collagen gene expression and production via ERK/Ets-1 signaling. These results suggest that Lipo-PGE1 could potentially be a therapeutic target in diseases with deregulated collagen turnover.

  7. Synchronized Targeting of Notch and ERBB Signaling Suppresses Melanoma Tumor Growth through Inhibition of Notch1 and ERBB3.

    Science.gov (United States)

    Zhang, Keman; Wong, Poki; Salvaggio, Christine; Salhi, Amel; Osman, Iman; Bedogni, Barbara

    2016-02-01

    Despite significant advances in melanoma therapy, melanoma remains the deadliest form of skin cancer, with a 5-year survival rate of only 15%. Thus, novel treatments are required to address this disease. Notch and ERBB are evolutionarily conserved signaling cascades required for the maintenance of melanocyte precursors. We show that active Notch1 (Notch1(NIC)) and active (phosphorylated) ERBB3 and ERBB2 correlate significantly and are similarly expressed in both mutated and wild-type BRAF melanomas, suggesting these receptors are co-reactivated in melanoma to promote survival. Whereas blocking either pathway triggers modest effects, combining a ?-secretase inhibitor to block Notch activation and a tyrosine kinase inhibitor to inhibit ERBB3/2 elicits synergistic effects, reducing cell viability by 90% and hampering melanoma tumor growth. Specific inhibition of Notch1 and ERBB3 mimics these results, suggesting these are the critical factors triggering melanoma tumor expansion. Notch and ERBB inhibition blunts AKT and NF?B signaling. Constitutive expression of NF?B partially rescues cell death. Blockade of both Notch and ERBB signaling inhibits the slow cycling JARID1B-positive cell population, which is critical for long-term maintenance of melanoma growth. We propose that blocking these pathways is an effective approach to treatment of melanoma patients regardless of whether they carry mutated or wild-type BRAF. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  8. Paeoniflorin reduces neomycin-induced ototoxicity in hair cells by suppression of reactive oxygen species generation and extracellularly regulated kinase signalization.

    Science.gov (United States)

    Yu, Xiaoyu; Fan, Zhaomin; Han, Yuechen; Zhang, Daogong; Xu, Lei; Wang, Mingming; Yang, Qianqian; Li, Hongrui; Zhou, Meijuan; Zhang, Lili; Sun, Gaoying; Bai, Xiaohui; Li, Jianfeng; Wang, Haibo

    2018-03-15

    The present study was designed to investigate the effect of paeoniflorin (PF) on neomycin-induced ototoxicity in hair cells (HCs). Here, we took advantage of C57BL/6 mice and cochlear explants culture to determine the role of PF in vivo and in vitro. We demonstrated that neomycin exposure induced severe hearing loss and HC damage, which was mediated by activated mitochondrial apoptosis pathway, promoted extracellular signal-regulated kinase (ERK) signaling as well as enhanced reactive oxygen species (ROS) generation in HCs. Interestingly, we found that PF pretreatment significantly alleviated neomycin-induced hearing loss, attenuated HC injury and decreased HC apoptosis caused by neomycin. Mechanistic studies revealed that PF could decrease cellular ROS levels, suppress the activation of ERK signaling and, subsequently, mitigate the imbalance of mitochondrial apoptotic pathway, thus protecting HCs from neomycin-induced apoptosis. This study indicates that PF may serve as an antioxidative and anti-apoptotic agent to prevent hearing loss caused by neomycin. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Suppression of Virulence of Toxigenic Vibrio cholerae by Anethole through the Cyclic AMP (cAMP)-cAMP Receptor Protein Signaling System.

    Science.gov (United States)

    Zahid, M Shamim Hasan; Awasthi, Sharda Prasad; Asakura, Masahiro; Chatterjee, Shruti; Hinenoya, Atsushi; Faruque, Shah M; Yamasaki, Shinji

    2015-01-01

    Use of natural compounds as antivirulence drugs could be an alternative therapeutic approach to modify the outcome of bacterial infections, particularly in view of growing resistance to available antimicrobials. Here, we show that sub-bactericidal concentration of anethole, a component of sweet fennel seed, could suppress virulence potential in O1 El Tor biotype strains of toxigenic Vibrio cholerae, the causative agent of the ongoing 7th cholera pandemic. The expression of cholera toxin (CT) and toxin coregulated pilus (TCP), the major virulence factors of V. cholerae, is controlled through a regulatory cascade involving activation of ToxT with synergistic coupling interaction of ToxR/ToxS with TcpP/TcpH. We present evidence that anethole inhibits in vitro expression of CT and TCP in a toxT-dependent but toxR/toxS-independent manner and through repression of tcpP/tcpH, by using bead-ELISA, western blotting and quantitative real-time RT-PCR assays. The cyclic AMP (cAMP)-cAMP receptor protein (CRP) is a well-studied global signaling system in bacterial pathogens, and this complex is known to suppress expression of tcpP/tcpH in V. cholerae. We find that anethole influences the virulence regulatory cascade by over-expressing cyaA and crp genes. Moreover, suppression of toxigenic V. cholerae-mediated fluid accumulation in ligated ileum of rabbit by anethole demonstrates its potentiality as an antivirulence drug candidate against the diseases caused by toxigenic V. cholerae. Taken altogether, these results revealing a mechanism of virulence inhibition in V. cholerae by the natural compound anethole, may have relevance in designing antivirulence compounds, particularly against multiple antibiotic resistant bacterial pathogens.

  10. Klotho gene delivery ameliorates renal hypertrophy and fibrosis in streptozotocin-induced diabetic rats by suppressing the Rho-associated coiled-coil kinase signaling pathway.

    Science.gov (United States)

    Deng, Minghong; Luo, Yumei; Li, Yunkui; Yang, Qiuchen; Deng, Xiaoqin; Wu, Ping; Ma, Houxun

    2015-07-01

    The present study aimed to investigate whether klotho gene delivery attenuated renal hypertrophy and fibrosis in streptozotocin-induced diabetic rats. A recombinant adeno-associated virus (rAAV) carrying mouse klotho full-length cDNA (rAAV.mKL), was constructed for in vivo investigation of klotho expression. Diabetes was induced in rats by a single tail vein injection of 60 mg/kg streptozotocin. Subsequently, the diabetic rats received an intravenous injection of rAAV.mKL, rAAV.green fluorescent protein (GFP) or phosphate-buffered saline (PBS). The Sprague-Dawley rat group received PBS and served as the control group. After 12 weeks, all the rats were sacrificed and ELISA, immunohistochemical and histological analyses, fluorescence microscopy, semi-quantitative reverse transcription-polymerase chain reaction and western blottin were performed. A single dose of rAAV.mKL was found to prevent the progression of renal hypertrophy and fibrosis for at least 12 weeks (duration of study). Klotho expression was suppressed in the diabetic rats, but was increased by rAAV.mKL delivery. rAAV.mKL significantly suppressed diabetes-induced renal hypertrophy and histopathological changes, reduced renal collagen fiber generation and decreased kidney hypertrophy index. In addition, rAAV.mKL decreased the protein expression levels of fibronectin and vimentin, while it downregulated the mRNA expression and activity of Rho-associated coiled-coil kinase (ROCK)I in the kidneys of the diabetic rats. These results indicated that klotho gene delivery ameliorated renal hypertrophy and fibrosis in diabetic rats, possibly by suppressing the ROCK signaling pathway. This may offer a novel approach for the long-term control and renoprotection of diabetes.

  11. Suppression of Virulence of Toxigenic Vibrio cholerae by Anethole through the Cyclic AMP (cAMP-cAMP Receptor Protein Signaling System.

    Directory of Open Access Journals (Sweden)

    M Shamim Hasan Zahid

    Full Text Available Use of natural compounds as antivirulence drugs could be an alternative therapeutic approach to modify the outcome of bacterial infections, particularly in view of growing resistance to available antimicrobials. Here, we show that sub-bactericidal concentration of anethole, a component of sweet fennel seed, could suppress virulence potential in O1 El Tor biotype strains of toxigenic Vibrio cholerae, the causative agent of the ongoing 7th cholera pandemic. The expression of cholera toxin (CT and toxin coregulated pilus (TCP, the major virulence factors of V. cholerae, is controlled through a regulatory cascade involving activation of ToxT with synergistic coupling interaction of ToxR/ToxS with TcpP/TcpH. We present evidence that anethole inhibits in vitro expression of CT and TCP in a toxT-dependent but toxR/toxS-independent manner and through repression of tcpP/tcpH, by using bead-ELISA, western blotting and quantitative real-time RT-PCR assays. The cyclic AMP (cAMP-cAMP receptor protein (CRP is a well-studied global signaling system in bacterial pathogens, and this complex is known to suppress expression of tcpP/tcpH in V. cholerae. We find that anethole influences the virulence regulatory cascade by over-expressing cyaA and crp genes. Moreover, suppression of toxigenic V. cholerae-mediated fluid accumulation in ligated ileum of rabbit by anethole demonstrates its potentiality as an antivirulence drug candidate against the diseases caused by toxigenic V. cholerae. Taken altogether, these results revealing a mechanism of virulence inhibition in V. cholerae by the natural compound anethole, may have relevance in designing antivirulence compounds, particularly against multiple antibiotic resistant bacterial pathogens.

  12. Dehydrocostus Lactone Suppresses Proliferation of Human Chronic Myeloid Leukemia Cells Through Bcr/Abl-JAK/STAT Signaling Pathways.

    Science.gov (United States)

    Cai, Hong; Qin, Xiaosong; Yang, Chunhui

    2017-10-01

    This study evaluates the anticancer effects of dehydrocostus lactone, a plant-derived sesquiterpene lactone, on human chronic myeloid leukemia cells. Dehydrocostus lactone significantly inhibits cell proliferation by inducing cells to undergo cell cycle arrest, apoptosis, and differentiation. Dehydrocostus lactone suppresses the expression of cyclin B1, cyclin A, cyclin E, cyclin-dependent kinase 2 (CDK2), and cyclin-dependent kinase 1 (CDK1) and increases p21 expression, resulting in S-G2/M phase arrest in K562 cells. Dehydrocostus lactone also induces apoptosis by increasing the generation of reactive oxygen species (ROS), disruption of mitochondrial membrane potential (MMP), and modulating the protein levels of Bcl-2 family members. We also found that dehydrocostus lactone significantly inhibits the phosphorylation expression of Bcr/Abl, STAT5, JAK2, and STAT3 and downstream molecules including p-CrkL, Mcl-1, Bcl-XL, and Bcl-2 proteins in K562 cells. At a low concentration, dehydrocostus lactone significantly increased CD11b and CD14 expression on the surface of K562 cells, and induced cells to differentiate into monocytes or mature macrophages. Taken together, this study provides new insight into the molecular mechanisms of dehydrocostus lactone actions that may contribute to the chemoprevention of chronic myeloid leukemia. J. Cell. Biochem. 118: 3381-3390, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  13. Asiatic acid ameliorates pulmonary fibrosis induced by bleomycin (BLM) via suppressing pro-fibrotic and inflammatory signaling pathways.

    Science.gov (United States)

    Dong, Shu-Hong; Liu, Yan-Wei; Wei, Feng; Tan, Hui-Zhen; Han, Zhi-Dong

    2017-05-01

    Idiopathic pulmonary fibrosis is known as a life-threatening disease with high mortality and limited therapeutic strategies. In addition, the molecular mechanism by which pulmonary fibrosis developed is not fully understood. Asiatic acid (AA) is a triterpenoid, isolated from Centella asiatica, exhibiting efficient anti-inflammatory and anti-oxidative activities. In our study, we attempted to explore the effect of Asiatic acid on bleomycin (BLM)-induced pulmonary fibrosis in mice. The findings indicated that pre-treatment with Asiatic acid inhibited BLM-induced lung injury and fibrosis progression in mice. Further, Asiatic acid down-regulates inflammatory cells infiltration in bronchoalveolar lavage fluid (BALF) and pro-inflammatory cytokines expression in lung tissue specimens induced by BLM. Also, Asiatic acid apparently suppressed transforming growth factor-beta 1 (TGF-β1) expression in tissues of lung, accompanied with Collagen I, Collagen III, α-SMA and matrix metalloproteinase (TIMP)-1 decreasing, as well as Smads and ERK1/2 inactivation. Of note, Asiatic acid reduces NOD-like receptor, pyrin domain containing-3 (NLRP3) inflammasome. The findings indicated that Asiatic acid might be an effective candidate for pulmonary fibrosis and inflammation treatment. Copyright © 2017. Published by Elsevier Masson SAS.

  14. Injury Signals Cooperate with Nf1 Loss to Relieve the Tumor-Suppressive Environment of Adult Peripheral Nerve

    Directory of Open Access Journals (Sweden)

    Sara Ribeiro

    2013-10-01

    Full Text Available Schwann cells are highly plastic cells that dedifferentiate to a progenitor-like state following injury. However, deregulation of this plasticity, may be involved in the formation of neurofibromas, mixed-cell tumors of Schwann cell (SC origin that arise upon loss of NF1. Here, we show that adult myelinating SCs (mSCs are refractory to Nf1 loss. However, in the context of injury, Nf1-deficient cells display opposing behaviors along the wounded nerve; distal to the injury, Nf1−/− mSCs redifferentiate normally, whereas at the wound site Nf1−/− mSCs give rise to neurofibromas in both Nf1+/+ and Nf1+/− backgrounds. Tracing experiments showed that distinct cell types within the tumor derive from Nf1-deficient SCs. This model of neurofibroma formation demonstrates that neurofibromas can originate from adult SCs and that the nerve environment can switch from tumor suppressive to tumor promoting at a site of injury. These findings have implications for both the characterization and treatment of neurofibromas.

  15. Jolkinolide B inhibits RANKL-induced osteoclastogenesis by suppressing the activation NF-κB and MAPK signaling pathways.

    Science.gov (United States)

    Ma, Xiaojun; Liu, Yupeng; Zhang, Yao; Yu, Xiaobing; Wang, Weiming; Zhao, Dewei

    2014-03-07

    Osteoclasts together with osteoblasts play pivotal roles in bone remodeling. The unique function and ability of osteoclasts to resorb bone makes them critical in both normal bone homeostasis and pathologic bone diseases such as osteoporosis and rheumatoid arthritis. Thus, new compounds that may inhibit osteoclastogenesis and osteoclast function may be of great value in the treatment of osteoclast-related diseases. In the present study, we examined the effect of jolkinolide B (JB), isolated from the root of Euphorbia fischeriana Steud on receptor activator of NF-κB ligand (RANKL)-induced osteoclast formation. We found that JB inhibited RANKL-induced osteoclast differentiation from bone marrow macrophages (BMMs) without cytotoxicity. Furthermore, the expression of osteoclastic marker genes, such as tartrate-resistant acid phosphatase (TRAP), cathepsin K (CtsK), and calcitonin receptor (CTR), was significantly inhibited. JB inhibited RANKL-induced activation of NF-κB by suppressing RANKL-mediated IκBα degradation. Moreover, JB inhibited RANKL-induced phosphorylation of mitogen-activated protein kinases (p38, JNK, and ERK). This study thus identifies JB as an inhibitor of osteoclast formation and provides evidence that JB might be an alternative medicine for preventing and treating osteolysis. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Exposure of Tg.AC transgenic mice to benzene suppresses hematopoietic progenitor cells and alters gene expression in critical signaling pathways

    International Nuclear Information System (INIS)

    Nwosu, Veronica C.; Kissling, Grace E.; Trempus, Carol S.; Honeycutt, Hayden; French, John E.

    2004-01-01

    The effects of acute benzene (BZ) exposure on hematopoietic progenitor cells (HPCs) derived from bone marrow cells were studied using homozygous male v-Ha-ras Tg.AC mice at 8-10 weeks of age. The mice were given 0.02% BZ in their drinking water for 28 days with the dose rate estimated to be 34 mg benzene/kg BW/day. Analysis of cultured HPCs indicated that BZ suppressed the proliferation of the multilineage colony forming unit-granulocyte, erythrocyte, macrophage, megakaryocyte (CFU-GEMM); colony forming unit-granulocyte, macrophage (CFU-GM); and blast forming unit erythrocyte/colony forming unit erythrocyte (BFUE/CFUE). A gene expression profile was generated using nylon arrays spotted with 23 cDNAs involved in selected signal pathways involved in cell distress, inflammation, DNA damage, cell cycle arrest, and apoptosis. Of the 23 marker genes, 6 (bax, c-fos, E124, hsf1, ikBa, and p57) were significantly (Mann-Whitney U tests, P < 0.05) overexpressed in BZ-exposed mice. Two genes (c-myc and IL-2) approached significance (at P = 0.053). The pattern of gene expression was consistent with BZ toxicity and the suppression of HPCs

  17. Zinc protoporphyrin suppresses cancer cell viability through a heme oxygenase-1-independent mechanism: the involvement of the Wnt/β-catenin signaling pathway.

    Science.gov (United States)

    Wang, Shuai; Avery, Jori E; Hannafon, Bethany N; Lind, Stuart E; Ding, Wei-Qun

    2013-06-01

    Zinc protoporphyrin (ZnPP), a known inhibitor of heme oxygenase-1 (HO-1), has been reported to have anticancer activity in both in vitro and in vivo model systems. While the mechanisms of ZnPP's anticancer activity remain to be elucidated, it is generally believed that ZnPP suppresses tumor growth through inhibition of HO-1 activity. We examined this hypothesis by altering cellular levels of HO-1 in human ovarian (A2780) and prostate cancer (DU145) cells and found that ZnPP inhibits cancer cell viability through an HO-1-independent mechanism. Neither over-expression nor knockdown of HO-1 significantly alters ZnPP's cytotoxicity in human cancer cells, indicating that HO-1 does not mediate ZnPP's inhibitory effect on cancer cell growth. Consistent with these observations, tin protoporphyrin (SnPP), a well-established HO-1 inhibitor, was found to be much less cytotoxic than ZnPP, and docosahexaenoic acid (DHA), an HO-1 inducer, enhanced ZnPP's cytotoxicity. In an effort to define the mechanisms of ZnPP-induced cytotoxicity, we found that ZnPP but not SnPP, diminished β-catenin expression through proteasome degradation and potently suppressed β-catenin-mediated signaling in our model systems. Thus, ZnPP-induced cytotoxicity is independent of HO-1 expression in cancer cells and the Wnt/β-catenin pathway is potentially involved in ZnPP's anticancer activity. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Neocryptotanshinone inhibits lipopolysaccharide-induced inflammation in RAW264.7 macrophages by suppression of NF-κB and iNOS signaling pathways

    Directory of Open Access Journals (Sweden)

    Chuanhong Wu

    2015-07-01

    Full Text Available Neocryptotanshinone (NCTS is a natural product isolated from traditional Chinese herb Salvia miltiorrhiza Bunge. In this study, we investigated its anti-inflammatory effects in lipopolysaccharide (LPS-stimulated mouse macrophage (RAW264.7 cells. MTT results showed that NCTS partly reversed LPS-induced cytotoxicity. Real-time PCR results showed that NCTS suppressed LPS-induced mRNA expression of inflammatory cytokines, including tumor necrosis factor α (TNFα, interleukin-6 (IL-6 and interleukin-1β (IL-1β. Moreover, NCTS could decrease LPS-induced nitric oxide (NO production. Western blotting results showed that NCTS could down-regulate LPS-induced expression of inducible nitric oxide synthase (iNOS, p-IκBα, p-IKKβ and p-NF-κB p65 without affecting cyclooxygenase-2 (COX-2. In addition, NCTS inhibited LPS-induced p-NF-κB p65 nuclear translocation. In conclusion, these data demonstrated that NCTS showed anti-inflammatory effect by suppression of NF-κB and iNOS signaling pathways.

  19. Hepatic anti-inflammatory effect of hexane extracts of Dioscorea batatas Decne: Possible suppression of toll-like receptor 4-mediated signaling.

    Science.gov (United States)

    Koo, Hyun Jung; Lee, SungRyul; Chang, Kwang Jin; Sohn, Eunsoo; Sohn, Eun-Hwa; Kang, Se Chan; Pyo, Suhkneung

    2017-08-01

    The hepatic anti-inflammatory potential of hexane extracts of Dioscorea batatas Decne edible part (EDH-1e) and bark (EDH-2b) were investigated in Western-type diet-fed apolipoprotein E null [ApoE (-/-)] mice and HepG2 cells. EDH-1e and EDH-2b suppressed the increased levels of tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, transforming growth factor beta 1 (TGF-β1), vascular cell adhesion protein 1 (VCAM-1), and monocyte chemoattractant protein-1 (MCP-1), and reduced infiltration of monocytes into liver tissue. The protein levels of Toll-like receptor 4 (TLR4) were also downregulated by EDH-1e and EDH-2b treatment as were the levels of activator protein 1 (AP-1), c-fos, and c-jun in the livers from Western-type diet-fed ApoE (-/-) mice and in lipopolysaccharide-stimulated HepG2 cells. Taken together, EDH-1e and EDH-2b attenuated hepatic inflammation and fibrosis via suppression of the TLR4-AP1-mediated signaling pathway. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  20. Tanshinone IIA inhibits AGEs-induced proliferation and migration of cultured vascular smooth muscle cells by suppressing ERK1/2 MAPK signaling

    Directory of Open Access Journals (Sweden)

    Ming Lu

    2018-01-01

    Full Text Available Objective(s: Vascular smooth muscle cells (VSMCs play a key role in the pathogenesis of diabetic vascular disease. Our current study sought to explore the effects of tanshinone IIA on the proliferation and migration of VSMCs induced by advanced glycation end products (AGEs. Materials and Methods: In this study, we examined the effects of tanshinone IIA by cell proliferation assay and cell migration assay. And we explored the underlying mechanism by Western blotting. Results: AGEs significantly induced the proliferation and migration of VSMCs, but treatment with tanshinone IIA attenuated these effects. AGEs could increase the activity of the ERK1/2 and p38 pathways but not the JNK pathway. Treatment with tanshinone IIA inhibited the AGEs-induced activation of the ERK1/2 pathway but not the p38 pathway.   Conclusion: Tanshinone IIA inhibits AGEs-induced proliferation and migration of VSMCs by suppressing the ERK1/2 MAPK signaling pathway.

  1. GATA-Dependent Glutaminolysis Drives Appressorium Formation in Magnaporthe oryzae by Suppressing TOR Inhibition of cAMP/PKA Signaling.

    Directory of Open Access Journals (Sweden)

    Margarita Marroquin-Guzman

    2015-04-01

    Full Text Available Fungal plant pathogens are persistent and global food security threats. To invade their hosts they often form highly specialized infection structures, known as appressoria. The cAMP/ PKA- and MAP kinase-signaling cascades have been functionally delineated as positive-acting pathways required for appressorium development. Negative-acting regulatory pathways that block appressorial development are not known. Here, we present the first detailed evidence that the conserved Target of Rapamycin (TOR signaling pathway is a powerful inhibitor of appressorium formation by the rice blast fungus Magnaporthe oryzae. We determined TOR signaling was activated in an M. oryzae mutant strain lacking a functional copy of the GATA transcription factor-encoding gene ASD4. Δasd4 mutant strains could not form appressoria and expressed GLN1, a glutamine synthetase-encoding orthologue silenced in wild type. Inappropriate expression of GLN1 increased the intracellular steady-state levels of glutamine in Δasd4 mutant strains during axenic growth when compared to wild type. Deleting GLN1 lowered glutamine levels and promoted appressorium formation by Δasd4 strains. Furthermore, glutamine is an agonist of TOR. Treating Δasd4 mutant strains with the specific TOR kinase inhibitor rapamycin restored appressorium development. Rapamycin was also shown to induce appressorium formation by wild type and Δcpka mutant strains on non-inductive hydrophilic surfaces but had no effect on the MAP kinase mutant Δpmk1. When taken together, we implicate Asd4 in regulating intracellular glutamine levels in order to modulate TOR inhibition of appressorium formation downstream of cPKA. This study thus provides novel insight into the metabolic mechanisms that underpin the highly regulated process of appressorium development.

  2. GATA-Dependent Glutaminolysis Drives Appressorium Formation in Magnaporthe oryzae by Suppressing TOR Inhibition of cAMP/PKA Signaling.

    Science.gov (United States)

    Marroquin-Guzman, Margarita; Wilson, Richard A

    2015-04-01

    Fungal plant pathogens are persistent and global food security threats. To invade their hosts they often form highly specialized infection structures, known as appressoria. The cAMP/ PKA- and MAP kinase-signaling cascades have been functionally delineated as positive-acting pathways required for appressorium development. Negative-acting regulatory pathways that block appressorial development are not known. Here, we present the first detailed evidence that the conserved Target of Rapamycin (TOR) signaling pathway is a powerful inhibitor of appressorium formation by the rice blast fungus Magnaporthe oryzae. We determined TOR signaling was activated in an M. oryzae mutant strain lacking a functional copy of the GATA transcription factor-encoding gene ASD4. Δasd4 mutant strains could not form appressoria and expressed GLN1, a glutamine synthetase-encoding orthologue silenced in wild type. Inappropriate expression of GLN1 increased the intracellular steady-state levels of glutamine in Δasd4 mutant strains during axenic growth when compared to wild type. Deleting GLN1 lowered glutamine levels and promoted appressorium formation by Δasd4 strains. Furthermore, glutamine is an agonist of TOR. Treating Δasd4 mutant strains with the specific TOR kinase inhibitor rapamycin restored appressorium development. Rapamycin was also shown to induce appressorium formation by wild type and Δcpka mutant strains on non-inductive hydrophilic surfaces but had no effect on the MAP kinase mutant Δpmk1. When taken together, we implicate Asd4 in regulating intracellular glutamine levels in order to modulate TOR inhibition of appressorium formation downstream of cPKA. This study thus provides novel insight into the metabolic mechanisms that underpin the highly regulated process of appressorium development.

  3. Expression of Death Receptor 4 Is Positively Regulated by MEK/ERK/AP-1 Signaling and Suppressed upon MEK Inhibition*

    Science.gov (United States)

    Yao, Weilong; Oh, You-Take; Deng, Jiusheng; Yue, Ping; Deng, Liang; Huang, Henry; Zhou, Wei; Sun, Shi-Yong

    2016-01-01

    Death receptor 4 (DR4) is a cell surface receptor for tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and triggers apoptosis upon ligation with TRAIL or aggregation. MEK/ERK signaling is a well known and the best-studied effector pathway downstream of Ras and Raf. This study focuses on determining the impact of pharmacological MEK inhibition on DR4 expression and elucidating the underlying mechanism. We found that several MEK inhibitors including MEK162, AZD6244, and PD0325901 effectively decreased DR4 protein levels including cell surface DR4 in different cancer cell lines. Accordingly, pre-treatment of TRAIL-sensitive cancer cell lines with a MEK inhibitor desensitized them to TRAIL-induced apoptosis. These results indicate that MEK inhibition negatively regulates DR4 expression and cell response to TRAIL-induced apoptosis. MEK inhibitors did not alter DR4 protein stability, rather decreased its mRNA levels, suggesting a transcriptional regulation. In contrast, enforced activation of MEK/ERK signaling by expressing ectopic B-Raf (V600E) or constitutively activated MEK1 (MEK1-CA) or MEK2 (MEK2-CA) activated ERK and increased DR4 expression; these effects were inhibited when a MEK inhibitor was present. Promoter analysis through deletion and mutation identified the AP-1 binding site as an essential response element for enhancing DR4 transactivation by MEK1-CA. Furthermore, inhibition of AP-1 by c-Jun knockdown abrogated the ability of MEK1-CA to increase DR4 promoter activity and DR4 expression. These results suggest an essential role of AP-1 in mediating MEK/ERK activation-induced DR4 expression. Our findings together highlight a previously undiscovered mechanism that positively regulates DR4 expression through activation of the MEK/ERK/AP-1 signaling pathway. PMID:27576686

  4. A novel synthetic Asiatic acid derivative induces apoptosis and inhibits proliferation and mobility of gastric cancer cells by suppressing STAT3 signaling pathway

    Directory of Open Access Journals (Sweden)

    Wang G

    2016-12-01

    Full Text Available Gang Wang,1 Yue Jing,2 Lingsen Cao,3 Changchang Gong,1 Zhunan Gong,1,3 Xiangrong Cao3 1Center for New Drug Research and Development, College of Life Science, Nanjing Normal University, 2Central Laboratory of Stomatology, Nanjing Stomatological Hospital, Medical School of Nanjing University, 3Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, People’s Republic of China Abstract: Activation of the transcription factor, signal transducers and activators of transcription 3 (STAT3, has been linked to the proliferation and migration of a variety of human cancer cells. These actions occur via the upregulation or downregulation of cell survival and tumor suppressor genes, respectively. Importantly, agents that can suppress STAT3 activation have the potential for use in the prevention and treatment of various cancers. In this study, an Asiatic acid (AA derivative, N-(2α,3β,23-acetoxyurs-12-en-28-oyl-L-proline methyl ester (AA-PMe, is reported to dose dependently suppress constitutive STAT3 activation in gastric cancer cells. This inhibition was mediated by blockade of Janus-activated kinase 2. Additionally, AA-PMe regulated the expression of STAT3-modulated gene products, including cyclin D1, Bax, Bcl-2, c-Myc, and matrix metalloproteinase (MMP-2 and MMP-9. Finally, transfection with both a STAT3 mimic and an inhibitor reversed the AA-PMe-driven modulation of STAT3 downstream gene products. Overall, these results suggest that AA-PMe is a novel blocker of STAT3 activation and has the potential for the prevention and treatment of gastric cancer. Keywords: gastric cancer, signal transducer and activator of transcription 3, Asiatic acid derivative, cell cycle, apoptosis, invasion

  5. Hepatitis B virus polymerase suppresses NF-κB signaling by inhibiting the activity of IKKs via interaction with Hsp90β.

    Directory of Open Access Journals (Sweden)

    Dan Liu

    Full Text Available Nuclear factor-κB (NF-κB plays a central role in the regulation of diverse biological processes, including immune responses, development, cell growth, and cell survival. To establish persistent infection, many viruses have evolved strategies to evade the host's antiviral immune defenses. In the case of hepatitis B virus (HBV, which can cause chronic infection in the liver, immune evasion strategies used by the virus are not fully understood. It has recently been reported that the polymerase of HBV (Pol inhibits interferon-β (IFN-β activity by disrupting the interaction between IKKε and the DDX3. In the current study, we found that HBV Pol suppressed NF-κB signaling, which can also contribute to IFN-β production. HBV Pol did not alter the level of NF-κB expression, but it prevented NF-κB subunits involved in both the canonical and non-canonical NF-κB pathways from entering the nucleus. Further experiments demonstrated that HBV Pol preferentially suppressed the activity of the IκB kinase (IKK complex by disrupting the association of IKK/NEMO with Cdc37/Hsp90, which is critical for the assembly of the IKK complex and recruitment of the IKK complex to the tumor necrosis factor type 1 receptor (TNF-R1. Furthermore, we found that HBV Pol inhibited the NF-κB-mediated transcription of target genes. Taken together, it is suggested that HBV Pol could counteract host innate immune responses by interfering with two distinct signaling pathways required for IFN-β activation. Our studies therefore shed light on a potential therapeutic target for persistent infection with HBV.

  6. Signal amplification and leakage current suppression in amorphous silicon p-i-n diodes by field profile tailoring

    International Nuclear Information System (INIS)

    Hong, W.S.; Zhong, F.; Mireshghi, A.; Perez-Mendez, V.

    1999-01-01

    The performance of amorphous silicon p-i-n diodes as radiation detectors in terms of signal amplitude can be greatly improved when there is a built-in signal gain mechanism. The authors describe an avalanche gain mechanism which is achieved by introducing stacked intrinsic, p-type, and n-type layers into the diode structure. They replaced the intrinsic layer of the conventional p-i-n diode with i 1 -p-i 2 -n-i 3 multilayers. The i 2 layer (typically 1 ∼ 3 microm) achieves an electric field > 10 6 V/cm, while maintaining the p-i interfaces to the metallic contact at electric fields 4 V/cm, when the diode is fully depleted. For use in photo-diode applications the whole structure is less than 10 microm thick. Avalanche gains of 10 ∼ 50 can be obtained when the diode is biased to ∼ 500 V. Also, dividing the electrodes to strips of 2 microm width and 20 microm pitch reduced the leakage current up to an order of magnitude, and increased light transmission without creating inactive regions

  7. Enhanced Inhibition of ERK Signaling by a Novel Allosteric MEK Inhibitor, CH5126766, That Suppresses Feedback Reactivation of RAF Activity

    Science.gov (United States)

    Joseph, Eric W.; Ohara, Kazuhiro; Miura, Takaaki; Sakamoto, Hiroshi; Matsuda, Yutaka; Tomii, Yasushi; Tachibana-Kondo, Yukako; Iikura, Hitoshi; Aoki, Toshihiro; Shimma, Nobuo; Arisawa, Mikio; Sowa, Yoshihiro; Poulikakos, Poulikos I.; Rosen, Neal; Aoki, Yuko; Sakai, Toshiyuki

    2014-01-01

    Tumors with mutant RAS are often dependent on extracellular signal–regulated kinase (ERK) signaling for growth; however, MEK inhibitors have only marginal antitumor activity in these tumors. MEK inhibitors relieve ERK-dependent feedback inhibition of RAF and cause induction of MEK phosphorylation. We have now identified a MEK inhibitor, CH5126766 (RO5126766), that has the unique property of inhibiting RAF kinase as well. CH5126766 binding causes MEK to adopt a conformation in which it cannot be phosphorylated by and released from RAF. This results in formation of a stable MEK/RAF complex and inhibition of RAF kinase. Consistent with this mechanism, this drug does not induce MEK phosphorylation. CH5126766 inhibits ERK signaling output more effectively than a standard MEK inhibitor that induces MEK phosphorylation and has potent antitumor activity as well. These results suggest that relief of RAF feedback limits pathway inhibition by standard MEK inhibitors. CH5126766 represents a new type of MEK inhibitor that causes MEK to become a dominant-negative inhibitor of RAF and that, in doing so, may have enhanced therapeutic activity in ERK-dependent tumors with mutant RAS. PMID:23667175

  8. Focal adhesion kinase, a downstream mediator of Raf-1 signaling, suppresses cellular adhesion, migration, and neuroendocrine markers in BON carcinoid cells.

    Science.gov (United States)

    Ning, Li; Chen, Herbert; Kunnimalaiyaan, Muthusamy

    2010-05-01

    We have recently reported that activation of the Raf-1/mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) kinase 1/2 (MEK1/2)/ERK1/2 signaling cascade in gastrointestinal carcinoid cell line (BON) alters cellular morphology and neuroendocrine phenotype. The mechanisms by which Raf-1 mediates these changes in carcinoid cells are unclear. Here, we report that activation of the Raf-1 signaling cascade in BON cells induced the expression of focal adhesion kinase (FAK) protein, suppressed the production of neuroendocrine markers, and resulted in significant decreases in cellular adhesion and migration. Importantly, inactivation of MEK1/2 by 1,4-diamino-2,3-dicyano-1,4-bis[2-aminophenylthio]butadiene or abolition of FAK induction in Raf-1-activated BON cells by targeted siRNA led to reversal of the Raf-1-mediated reduction in neuroendocrine markers and cellular adhesion and migration. Phosphorylation site-specific antibodies detected the phosphorylated FAK(Tyr407), but not FAK(Tyr397), in these Raf-1-activated cells, indicating that FAK(Tyr407) may be associated with changes in the neuroendocrine phenotype. Overexpression of constitutively active FAK plasmids (wild-type FAK or FAK(Tyr397) mutant) into BON cells reduced neuroendocrine markers, whereas the FAK(Tyr407) mutant plasmid did not show any decrease in the levels of neuroendocrine markers, indicating that phosphorylation of FAK at the Tyr(407) residue may be important for these effects. Our results showed for the first time that FAK is an essential downstream effector of the Raf-1/MEK1/2/ERK1/2 signaling cascade and negatively regulated the neuroendocrine and metastatic phenotype in BON cells. (c)2010 AACR.

  9. A hepatoprotective Lindera obtusiloba extract suppresses growth and attenuates insulin like growth factor-1 receptor signaling and NF-kappaB activity in human liver cancer cell lines

    Directory of Open Access Journals (Sweden)

    Stroh Thorsten

    2011-05-01

    Full Text Available Abstract Background In traditional Chinese and Korean medicine, an aqueous extract derived from wood and bark of the Japanese spice bush Lindera obtusiloba (L.obtusiloba is applied to treat inflammations and chronic liver diseases including hepatocellular carcinoma. We previously demonstrated anti-fibrotic effects of L.obtusiloba extract in hepatic stellate cells. Thus, we here consequently examine anti-neoplastic effects of L.obtusiloba extract on human hepatocellular carcinoma (HCC cell lines and the signaling pathways involved. Methods Four human HCC cell lines representing diverse stages of differentiation were treated with L.obtusiloba extract, standardized according to its known suppressive effects on proliferation and TGF-β-expression. Beside measurement of proliferation, invasion and apoptosis, effects on signal transduction and NF-κB-activity were determined. Results L.obtusiloba extract inhibited proliferation and induced apoptosis in all HCC cell lines and provoked a reduced basal and IGF-1-induced activation of the IGF-1R signaling cascade and a reduced transcriptional NF-κB-activity, particularly in the poorly differentiated SK-Hep1 cells. Pointing to anti-angiogenic effects, L.obtusiloba extract attenuated the basal and IGF-1-induced expression of hypoxia inducible factor-1α, vascular endothelial growth factor, peroxisome proliferator-activated receptor-γ, cyclooxygenase-2 and inducible nitric oxide synthase. Conclusions The traditional application of the extract is confirmed by our experimental data. Due to its potential to inhibit critical receptor tyrosine kinases involved in HCC progression via the IGF-1 signaling pathway and NF-κB, the standardized L.obtusiloba extract should be further analysed for its active compounds and explored as (complementary treatment option for HCC.

  10. Suppression of melanogenesis by a newly synthesized compound, MHY966 via the nitric oxide/protein kinase G signaling pathway in murine skin.

    Science.gov (United States)

    Choi, Yeon Ja; Uehara, Yohei; Park, Ji Young; Chung, Ki Wung; Ha, Young Mi; Kim, Ji Min; Song, Yu Min; Chun, Pusoon; Park, June Whan; Moon, Hyung Ryong; Chung, Hae Young

    2012-12-01

    Ultraviolet B (UVB) radiation is the main physiological stimulus for skin pigmentation. Nitric oxide (NO) and the NO/PKG signaling pathway play an important role in UVB-induced melanogenesis, which is related to the induction of expression of tyrosinase. In an attempt to find a novel anti-melanogenic agent, we synthesized a new compound, 2-bromo-4-(5-chloro-benzo[d]thiazol-2-yl) phenol (MHY966). The purpose of this study was to investigate the action of MHY966 on NO and the NO-mediated signaling pathway using in vitro and in vivo models of melanogenesis. NO generation, melanin synthesis, and the expression of tyrosinase and PKG were measured in B16F10 melanoma cells to verify the anti-melanogenic effect of MHY966 in vitro. Next, melanin-possessing hairless mice were pre-treated with MHY966 and then irradiated with UVB repeatedly. Morphological, histological, and biochemical analyses including the expressions of PKG, tryosinase and nuclear MITF, and productions of nitric oxide, peroxynitrite and ROS were conducted. MHY966 effectively inhibited NO generation and subsequent melanin synthesis induced by sodium nitroprusside, an NO donor, and suppressed the expression of tyrosinase and PKG. Topical application of MHY966 dose-dependently attenuated UVB-induced pigmentation in a mouse model. This hypopigmentation effect induced by MHY966 treatment was mediated by the down-regulation of tyrosinase, PKG, and nuclear MITF, which was accompanied by decreased NO and NO-related oxidative stress. The novel compound, MHY966 had an inhibitory effect on NO generation and the NO-mediated signaling pathway leading to the down-regulation of tyrosinase. The significance of the present study is the finding of a promising anti-melanogenic agent targeting the NO/PKG signaling pathway. Copyright © 2012 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

  11. Bufalin-inhibited migration and invasion in human osteosarcoma U-2 OS cells is carried out by suppression of the matrix metalloproteinase-2, ERK, and JNK signaling pathways.

    Science.gov (United States)

    Chueh, Fu-Shin; Chen, Ya-Yin; Huang, An-Cheng; Ho, Heng-Chien; Liao, Ching-Lung; Yang, Jai-Sing; Kuo, Chao-Lin; Chung, Jing-Gung

    2014-01-01

    Bufalin has been shown to exhibit multiple pharmacological activities, including induction of apoptosis in many types of cancer cell lines. Osteosarcoma is a type of cancer which is difficult to treat and the purpose of this study was to investigate the effects of bufalin on the migration and invasion of human osteosarcoma U-2 OS cells. The wound healing assay and Boyden chamber transwell assay were used for examining the migration of U-2 OS cells. Western blotting and gelatin zymography assays were used for theexpression and activities of metalloproteinase (MMP)-2, MMP-7 or MMP-9 levels. Western blotting analysis also was used for measuring the levels of growth factor receptor-bound protein 2 (GRB2), son of sevenless homolog 1 (SOS1), c-Jun N-terminal kinases 1/2 (JNK1/2), extracellular signal-regulated kinase 1/2 (ERK1/2), and p38 in bufalin-treated U-2 OS cells. Bufalin inhibited the cell migration and invasion of U-2 OS cells in vitro. Moreover, bufalin reduced MMP-2 and MMP-9 enzyme activities of U-2 OS cells. Bufalin also suppressed the protein level of MMP-2 and reduced the levels of mitogen-activated protein kinases (MAPKs) such as JNK1/2 and ERK1/2 signals in U-2 OS cells. Our results suggest that signaling pathways for bufalin-inhibited migration and invasion of U-2 OS cells might be mediated through blocking MAPK signaling and resulting in the inhibition of MMP-2. Bufalin could be a useful agent to develop as a novel antitumor agent by virtue of its ability to inhibit tumor cell migration and invasion. Copyright © 2011 Wiley Periodicals, Inc.

  12. Activated factor X signaling via protease-activated receptor 2 suppresses pro-inflammatory cytokine production from LPS-stimulated myeloid cells.

    LENUS (Irish Health Repository)

    Gleeson, Eimear M

    2013-07-19

    Vitamin K-dependent proteases generated in response to vascular injury and infection enable fibrin clot formation, but also trigger distinct immuno-regulatory signaling pathways on myeloid cells. Factor Xa, a protease crucial for blood coagulation, also induces protease-activated receptor-dependent cell signaling. Factor Xa can bind both monocytes and macrophages, but whether factor Xa-dependent signaling stimulates or suppresses myeloid cell cytokine production in response to Toll-like receptor activation is not known. In this study, exposure to factor Xa significantly impaired pro-inflammatory cytokine production from lipopolysaccharide-treated peripheral blood mononuclear cells, THP-1 monocytic cells and murine macrophages. Furthermore, factor Xa inhibited nuclear factor-kappa B activation in THP-1 reporter cells, requiring phosphatidylinositide 3-kinase activity for its anti-inflammatory effect. Active-site blockade, γ-carboxyglutamic acid domain truncation and a peptide mimic of the factor Xa inter-epidermal growth factor-like region prevented factor Xa inhibition of lipopolysaccharide-induced tumour necrosis factor-α release. In addition, factor Xa anti-inflammatory activity was markedly attenuated by the presence of an antagonist of protease-activated receptor 2, but not protease-activated receptor 1. The key role of protease-activated receptor 2 in eliciting factor Xa-dependent anti-inflammatory signaling on macrophages was further underscored by the inability of factor Xa to mediate inhibition of tumour necrosis factor-α and interleukin-6 release from murine bone marrow-derived protease-activated receptor 2-deficient macrophages. We also show for the first time that, in addition to protease-activated receptor 2, factor Xa requires a receptor-associated protein-sensitive low-density lipoprotein receptor to inhibit lipopolysaccharide-induced cytokine production. Collectively, this study supports a novel function for factor Xa as an endogenous, receptor

  13. Mangiferin inhibits mastitis induced by LPS via suppressing NF-ĸB and NLRP3 signaling pathways.

    Science.gov (United States)

    Qu, Shihui; Wang, Wenqing; Li, Depeng; Li, Shumin; Zhang, Like; Fu, Yunhe; Zhang, Naisheng

    2017-02-01

    During the past era, small molecules derived from various plants have attracted extensive attention for their versatile medicinal benefits. Among these, one organic molecule called mangiferin from certain plant species including mangoes and honey bush tea is widely used in treating inflammation. In this study, a LPS-induced mastitis model in mouse is established to investigate the anti-inflammatory effects and mechanism of mangiferin. The result shows that mangiferin significantly alleviates LPS-induced histopathology, meanwhile, also decreases LPS-induced MPO activity. Furthermore, mangiferin treatment remarkably impeded the expression of pro-inflammatory cytokines TNF-α, IL-1β, and IL-6. In addition, mangiferin was found to inhibit LPS-induced NF-ĸB and NLRP3 inflammasome activation. In conclusion, these results suggested that LPS-induced mastitis can be abated by mangiferin through inhibiting NF-ĸB and NLRP3 signaling pathways. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Baicalein suppresses the viability of MG-63 osteosarcoma cells through inhibiting c-MYC expression via Wnt signaling pathway.

    Science.gov (United States)

    He, Nengbin; Zhang, Zhichang

    2015-07-01

    The major reason responsible for the poor prognosis of osteosarcoma is the malignant proliferation of osteosarcoma cells. The activated Wnt/β-catenin signaling induces c-MYC gene transcription and results in osteocytes' carcinomatous change, which contributes to osteosarcoma development, so c-MYC gene is one of the therapeutic targets. The role of multiple botanical extracts in the expression of β-catenin's target gene c-MYC in osteosarcoma MG-63 cells was tested by cellomics high content screening. Baicalein was identified as the most effective one which can inhibit the proliferation and promote the apoptosis of MG-63 cells in a dose-dependent manner by cell counting kit-8 test and fluorescence-activated cell sorting, respectively. This process was associated with the decreased levels of β-catenin and its target gene c-MYC, identified by q-PCR and Western blotting, respectively. When MG-63 cells were treated with both baicalein and JNK inhibitor SP600125, the apoptosis and expression of c-MYC were not significantly decreased. After the construct pcDNA3.1-BANCR (BRAF-regulated lncRNA 1) was transfected into MG-63 cells, RT-PCR, Western blotting and CCK-8 assay showed that BANCR was positively correlated with baicalein. These results indicated that baicalein inhibited osteosarcoma cell proliferation and promoted apoptosis by targeting c-MYC gene through Wnt signaling, in which JNK and BANCR were also involved as well as β-catenin, suggesting a new potential mechanism for us to better understand the inhibiting effect of baicalein on osteosarcoma.

  15. Recombinant Human Endostatin Suppresses Mouse Osteoclast Formation by Inhibiting the NF-κB and MAPKs Signaling Pathways

    Directory of Open Access Journals (Sweden)

    Non eChen

    2016-06-01

    Full Text Available Rheumatoid arthritis is an autoimmune disease characterized by synovial hyperplasia and progressive joint destruction. As reported previously, recombinant human endostatin (rhEndostatin is associated with inhibition of joint bone destruction present in rat adjuvant-induced arthritis; however, the effect of rhEndostatin on bone destruction is not known. This study was designed to assess the inhibitory effect and mechanisms of rhEndostatin on formation and function of osteoclasts in vitro, and to gain insight into the mechanism underlying the inhibitory effect of bone destruction. Bone marrow-derived macrophages isolated from BALB/c mice were stimulated with receptor activator of NF-κB ligand (RANKL and macrophage colony-stimulating factor to establish osteoclast formation. Osteoclast formation was determined by TRAP staining. Cell viability of BMMs affected by rhEndostatin was determined using a MTT assay. Bone resorption was examined with a bone resorption pits assay. The expression of osteoclast-specific markers was analyzed using quantitative real-time PCR. The related signaling pathways were examined using a Luciferase reporter assay and western blot analysis. Indeed, rhEndostatin showed a significant reduction in the number of osteoclast-like cells and early-stage bone resorption. Moreover, molecular analysis demonstrated that rhEndostatin attenuated RANKL-induced NF-κB signaling by inhibiting the phosphorylation of IκBα and NF-κB p65 nuclear translocation. Furthermore, rhEndostatin significantly inhibited the activation of RANKL-dependent mitogen-activated protein kinases (MAPKs, such as ERK1/2, JNK, and p38. Hence, we demonstrated for the first time that preventing the formation and function of osteoclasts is an important anti-bone destruction mechanism of rhEndostatin, which might be useful in the prevention and treatment of bone destruction in RA.

  16. 3,4-Dihydroxybenzalactone Suppresses Human Non-Small Cell Lung Carcinoma Cells Metastasis via Suppression of Epithelial to Mesenchymal Transition, ROS-Mediated PI3K/AKT/MAPK/MMP and NFκB Signaling Pathways.

    Science.gov (United States)

    Chao, Wei; Deng, Jeng-Shyan; Li, Pei-Ying; Liang, Yu-Chia; Huang, Guan-Jhong

    2017-03-28

    3,4-Dihydroxybenzalactone (DBL) was isolated from Phellinus linteus (PL), which is a folk medicine possessing various physiological effects. In this study, we used highly metastatic A549 cells to investigate efficacy of DBL inhibition of cancer metastasis and possible mechanisms. The results revealed DBL inhibited migratory and invasive abilities of cancer cells at noncytotoxic concentrations. We found DBL suppressed enzymatic activities, protein expression, and RNA levels of matrix metalloproteinase (MMP)-2 and MMP-9. Western blot results showed DBL decreased phosphoinositide 3-kinase (PI3K)/AKT, phosphorylation status of mitogen-activated protein kinases (MAPKs), and focal adhesion kinase (FAK)/paxillin, which correlated with cell migratory ability. DBL also affected epithelial to mesenchymal transition (EMT)-related biomarkers. In addition, DBL enhanced cytoprotective effects through elevated antioxidant enzymes including heme oxygenase 1 (HO-1), catalase, glutathione peroxidase (GPx), and superoxide dismutase (SOD). Moreover, DBL influenced the nuclear translocation of nuclear factor κB (NFκB), nuclear factor erythroid 2-related factor 2 (Nrf2), Snail, and Slug in A549 cells. Taken together, these results suggested that treatment with DBL may act as a potential candidate to inhibit lung cancer metastasis by inhibiting MMP-2 and -9 via affecting PI3K/AKT, MAPKs, FAK/paxillin, EMT/Snail and Slug, Nrf2/antioxidant enzymes, and NFκB signaling pathways.

  17. Anorexigenic and Orexigenic Hormone Modulation of Mammalian Target of Rapamycin Complex 1 Activity and the Regulation of Hypothalamic Agouti-Related Protein mRNA Expression

    Directory of Open Access Journals (Sweden)

    Kenneth R. Watterson

    2012-03-01

    Full Text Available Activation of mammalian target of rapamycin 1 (mTORC1 by nutrients, insulin and leptin leads to appetite suppression (anorexia. Contrastingly, increased AMP-activated protein kinase (AMPK activity by ghrelin promotes appetite (orexia. However, the interplay between these mechanisms remains poorly defined. The relationship between the anorexigenic hormones, insulin and leptin, and the orexigenic hormone, ghrelin, on mTORC1 signalling was examined using S6 kinase phosphorylation as a marker for changes in mTORC1 activity in mouse hypothalamic GT1-7 cells. Additionally, the contribution of AMPK and mTORC1 signalling in relation to insulin-, leptin- and ghrelin-driven alterations to mouse hypothalamic agouti-related protein (AgRP mRNA levels was examined. Insulin and leptin increase mTORC1 activity in a phosphoinositide-3-kinase (PI3K- and protein kinase B (PKB-dependent manner, compared to vehicle controls, whereas increasing AMPK activity inhibits mTORC1 activity and blocks the actions of the anorexigenic hormones. Ghrelin mediates an AMPK-dependent decrease in mTORC1 activity and increases hypothalamic AgRP mRNA levels, the latter effect being prevented by insulin in an mTORC1-dependent manner. In conclusion, mTORC1 acts as an integration node in hypothalamic neurons for hormone-derived PI3K and AMPK signalling and mediates at least part of the assimilated output of anorexigenic and orexigenic hormone actions in the hypothalamus.

  18. Hydrogen sulfide-releasing naproxen suppresses colon cancer cell growth and inhibits NF-κB signaling

    Directory of Open Access Journals (Sweden)

    Kodela R

    2015-08-01

    Full Text Available Ravinder Kodela,1 Niharika Nath,2 Mitali Chattopadhyay,1 Diandra E Nesbitt,1 Carlos A Velázquez-Martínez,3 Khosrow Kashfi11Department of Physiology, Pharmacology and Neuroscience, Sophie Davis School of Biomedical Education, City University of New York Medical School, 2Department of Life Sciences, New York Institute of Technology, New York, NY, USA; 3Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, AB, Canada Abstract: Colorectal cancer (CRC is the second leading cause of death due to cancer and the third most common cancer in men and women in the USA. Nuclear factor kappa B (NF-κB is known to be activated in CRC and is strongly implicated in its development and progression. Therefore, activated NF-κB constitutes a bona fide target for drug development in this type of malignancy. Many epidemiological and interventional studies have established nonsteroidal anti-inflammatory drugs (NSAIDs as a viable chemopreventive strategy against CRC. Our previous studies have shown that several novel hydrogen sulfide-releasing NSAIDs are promising anticancer agents and are safer derivatives of NSAIDs. In this study, we examined the growth inhibitory effect of a novel H2S-releasing naproxen (HS-NAP, which has a repertoire as a cardiovascular-safe NSAID, for its effects on cell proliferation, cell cycle phase transitions, and apoptosis using HT-29 human colon cancer cells. We also investigated its effect as a chemopreventive agent in a xenograft mouse model. HS-NAP suppressed the growth of HT-29 cells by induction of G0/G1 arrest and apoptosis and downregulated NF-κB. Tumor xenografts in mice were significantly reduced in volume. The decrease in tumor mass was associated with a reduction of cell proliferation, induction of apoptosis, and decreases in NF-κB levels in vivo. Therefore, HS-NAP demonstrates strong anticancer potential in CRC. Keywords: nonsteroidal anti-inflammatory drugs, cell cycle, apoptosis, xenograft, NF

  19. Norcantharidin inhibits tumor growth and vasculogenic mimicry of human gallbladder carcinomas by suppression of the PI3-K/MMPs/Ln-5γ2 signaling pathway

    International Nuclear Information System (INIS)

    Zhang, Jing-Tao; Sun, Wei; Zhang, Wen-Zhong; Ge, Chun-Yan; Liu, Zhong-Yan; Zhao, Ze-Ming; Lu, Xing-Sui; Fan, Yue-Zu

    2014-01-01

    < 0.01, vs. control group); NCTD down-regulated expression of these VM signaling-related markers in vitro and in vivo. NCTD inhibited tumor growth and VM of human GBCs in vitro and in vivo by suppression of the PI3-K/MMPs/Ln-5γ2 signaling pathway. It is firstly concluded that NCTD may be a potential anti-VM agent for human GBCs

  20. Inhibitory Effects of KP-A159, a Thiazolopyridine Derivative, on Osteoclast Differentiation, Function, and Inflammatory Bone Loss via Suppression of RANKL-Induced MAP Kinase Signaling Pathway.

    Directory of Open Access Journals (Sweden)

    Hye Jung Ihn

    Full Text Available Abnormally elevated formation and activation of osteoclasts are primary causes for a majority of skeletal diseases. In this study, we found that KP-A159, a newly synthesized thiazolopyridine derivative, inhibited osteoclast differentiation and function in vitro, and inflammatory bone loss in vivo. KP-A159 did not cause a cytotoxic response in bone marrow macrophages (BMMs, but significantly inhibited the formation of multinucleated tartrate-resistant acid phosphatase (TRAP-positive osteoclasts induced by macrophage colony-stimulating factor (M-CSF and receptor activator of nuclear factor-κB ligand (RANKL. KP-A159 also dramatically inhibited the expression of marker genes related to osteoclast differentiation, including TRAP (Acp5, cathepsin K (Ctsk, dendritic cell-specific transmembrane protein (Dcstamp, matrix metallopeptidase 9 (Mmp9, and nuclear factor of activated T-cells, cytoplasmic 1 (Nfatc1. Moreover, actin ring and resorption pit formation were inhibited by KP-A159. Analysis of the signaling pathway involved showed that KP-A159 inhibited RANKL-induced activation of extracellular signal-regulated kinase (ERK, c-Jun N-terminal kinase (JNK, and mitogen-activated protein kinase kinase1/2 (MEK1/2. In a mouse inflammatory bone loss model, KP-A159 significantly rescued lipopolysaccharide (LPS-induced bone loss by suppressing osteoclast numbers. Therefore, KP-A159 targets osteoclasts, and may be a potential candidate compound for prevention and/or treatment of inflammatory bone loss.