Targeted Inhibition of Pancreatic Acinar Cell Calcineurin Is a Novel Strategy to Prevent Post-ERCP PancreatitisSummary

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Abrahim I. Orabi

2017-01-01

Full Text Available Background & Aims: There is a pressing need to develop effective preventative therapies for post–endoscopic retrograde cholangiopancreatography pancreatitis (PEP. We showed that early PEP events are induced through the calcium-activated phosphatase calcineurin and that global calcineurin deletion abolishes PEP in mice. A crucial question is whether acinar cell calcineurin controls the initiation of PEP in vivo. Methods: We used a mouse model of PEP and examined the effects of in vivo acinar cell-specific calcineurin deletion by either generating a conditional knockout line or infusing a novel adeno-associated virus–pancreatic elastase improved Cre (I–iCre into the pancreatic duct of a calcineurin floxed line. Results: We found that PEP is dependent on acinar cell calcineurin in vivo, and this led us to determine that calcineurin inhibitors, infused within the radiocontrast, largely can prevent PEP. Conclusions: These results provide the impetus for launching clinical trials to test the efficacy of intraductal calcineurin inhibitors to prevent PEP. Keywords: Adeno-Associated Virus, Calcineurin B1, FK506, Cyclosporine A, Intraductal Delivery

Regulation of gap junction conductance by calcineurin through Cx43 phosphorylation: implications for action potential conduction.

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Jabr, Rita I; Hatch, Fiona S; Salvage, Samantha C; Orlowski, Alejandro; Lampe, Paul D; Fry, Christopher H

2016-11-01

Cardiac arrhythmias are associated with raised intracellular [Ca 2+ ] and slowed action potential conduction caused by reduced gap junction (GJ) electrical conductance (Gj). Ventricular GJs are composed of connexin proteins (Cx43), with Gj determined by Cx43 phosphorylation status. Connexin phosphorylation is an interplay between protein kinases and phosphatases but the precise pathways are unknown. We aimed to identify key Ca 2+ -dependent phosphorylation sites on Cx43 that regulate cardiac gap junction conductance and action potential conduction velocity. We investigated the role of the Ca 2+ -dependent phosphatase, calcineurin. Intracellular [Ca 2+ ] was raised in guinea-pig myocardium by a low-Na solution or increased stimulation. Conduction velocity and Gj were measured in multicellular strips. Phosphorylation of Cx43 serine residues (S365 and S368) and of the intermediary regulator I1 at threonine35 was measured by Western blot. Measurements were made in the presence and absence of inhibitors to calcineurin, I1 or protein phosphatase-1 and phosphatase-2.Raised [Ca 2 + ] i decreased Gj, reduced Cx43 phosphorylation at S365 and increased it at S368; these changes were reversed by calcineurin inhibitors. Cx43-S368 phosphorylation was reversed by the protein kinase C inhibitor chelerythrine. Raised [Ca 2+ ] i also decreased I1 phosphorylation, also prevented by calcineurin inhibitors, to increase activity of the Ca 2+ -independent phosphatase, PPI. The PP1 inhibitor, tautomycin, prevented Cx43-365 dephosphorylation, Cx43-S368 phosphorylation and Gj reduction in raised [Ca 2+ ] i . PP2A had no role. Conduction velocity was reduced by raised [Ca 2+ ] i and reversed by calcineurin inhibitors. Reduced action potential conduction and Gj in raised [Ca 2+ ] are regulated by calcineurin-dependent Cx43-S365 phosphorylation, leading to Cx43-S368 dephosphorylation. The calcineurin action is indirect, via I1 dephosphorylation and subsequent activation of PP1.

Calcineurin /NFAT activation-dependence of leptin synthesis and vascular growth in response to mechanical stretch

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Nadia Soudani

2016-09-01

Full Text Available Background and Aims- Hypertension and obesity are important risk factors of cardiovascular disease. They are both associated with high leptin levels and have been shown to promote vascular hypertrophy, through the RhoA/ROCK and ERK1/2 phosphorylation. Calcineurin/NFAT activation also induces vascular hypertrophy by upregulating various genes. This study aimed to decipher whether a crosstalk exists between the RhoA/ROCK pathway, Ca+2/calcineurin/NFAT pathway, and ERK1/2 phosphorylation in the process of mechanical stretch-induced vascular smooth muscle cell (VSMC hypertrophy and leptin synthesis. Methods and Results- Rat portal vein (RPV organ culture was used to investigate the effect of mechanical stretch and exogenous leptin (3.1 nM on VSMC hypertrophy and leptin synthesis. Results showed that stretching the RPV significantly upregulated leptin secretion, mRNA and protein expression, which were inhibited by the calcium channel blocker nifedipine (10 μM, the selective calcineurin inhibitor FK506 (1 nM and the ERK1/2 inhibitor PD98059 (1 μM. The transcription inhibitor actinomycin D (0.1M and the translation inhibitor cycloheximide (1 mM significantly decreased stretch-induced leptin protein expression. Mechanical stretch or leptin caused an increase in wet weight changes and protein synthesis, considered as hypertrophic markers, while they were inhibited by FK506 (0.1 nM; 1 nM. In addition, stretch or exogenous leptin significantly increased calcineurin activity and MCIP1 expression whereas leptin induced NFAT nuclear translocation in VSMCs. Moreover, in response to stretch or exogenous leptin, the Rho inhibitor C3 exoenzyme (30 ng/mL, the ROCK inhibitor Y-27632 (10 μM, and the actin depolymerization agents Latrunculin B (50 nM and cytochalasin D (1 μM reduced calcineurin activation and NFAT nuclear translocation. ERK1/2 phosphorylation was inhibited by FK506 and C3. Conclusions- Mechanical stretch-induced VSMC hypertrophy and leptin

FKBP12-Dependent Inhibition of Calcineurin Mediates Immunosuppressive Antifungal Drug Action in Malassezia.

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Ianiri, Giuseppe; Applen Clancey, Shelly; Lee, Soo Chan; Heitman, Joseph

2017-10-24

The genus Malassezia includes yeasts that are commonly found on the skin or hair of animals and humans as commensals and are associated with a number of skin disorders. We have previously developed an Agrobacterium tumefaciens transformation system effective for both targeted gene deletion and insertional mutagenesis in Malassezia furfur and M. sympodialis In the present study, these molecular resources were applied to characterize the immunophilin FKBP12 as the target of tacrolimus (FK506), ascomycin, and pimecrolimus, which are calcineurin inhibitors that are used as alternatives to corticosteroids in the treatment of inflammatory skin disorders such as those associated with Malassezia species. While M. furfur and M. sympodialis showed in vitro sensitivity to these agents, fkb1 Δ mutants displayed full resistance to all three of them, confirming that FKBP12 is the target of these calcineurin inhibitors and is essential for their activity. We found that calcineurin inhibitors act additively with fluconazole through an FKBP12-dependent mechanism. Spontaneous M. sympodialis isolates resistant to calcineurin inhibitors had mutations in the gene encoding FKBP12 in regions predicted to affect the interactions between FKBP12 and FK506 based on structural modeling. Due to the presence of homopolymer nucleotide repeats in the gene encoding FKBP12, an msh2 Δ hypermutator of M. sympodialis was engineered and exhibited an increase of more than 20-fold in the rate of emergence of resistance to FK506 compared to that of the wild-type strain, with the majority of the mutations found in these repeats. IMPORTANCE Malassezia species are the most abundant fungal components of the mammalian and human skin microbiome. Although they belong to the natural skin commensal flora of humans, they are also associated with a variety of clinical skin disorders. The standard treatment for Malassezia -associated inflammatory skin infections is topical corticosteroids, although their use

Long-term outcomes of thoracic transplant recipients following conversion to everolimus with reduced calcineurin inhibitor in a multicenter, open-label, randomized trial lv

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Gullestad, Lars; Eiskjaer, Hans; Gustafsson, Finn

2016-01-01

The NOCTET study randomized 282 patients ≥1 year after heart or lung transplantation to continue conventional calcineurin inhibitor (CNI) therapy or to start everolimus with reduced-exposure CNI. Last follow-up, at ≥5 years postrandomization (mean: 5.6 years) was attended by 72/140 everolimus...

The Privilege of Induction Avoidance and Calcineurin Inhibitors Withdrawal in 2 Haplotype HLA Matched White Kidney Transplantation.

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Brifkani, Zaid; Brennan, Daniel C; Lentine, Krista L; Horwedel, Timothy A; Malone, Andrew F; Delos Santos, Rowena; Maw, Thin Thin; Alhamad, Tarek

2017-03-01

White recipients of 2-haplotype HLA-matched living kidney transplants are perceived to be of low immunologic risk. Little is known about the safety of induction avoidance and calcineurin inhibitor withdrawal in these patients. We reviewed our experience at a single center and compared it to Organ Procurement and Transplantation Network (OPTN) registry data and only included 2-haplotype HLA-matched white living kidney transplants recipients between 2000 and 2013. There were 56 recipients in a single center (where no induction was given) and 2976 recipients in the OPTN. Among the OPTN recipients, 1285 received no induction, 903 basiliximab, 608 thymoglobulin, and 180 alemtuzumab. First-year acute rejection rates were similar after induction-free transplantation among the center and induced groups nationally. Compared with induction-free transplantation in the national data, there was no decrease in graft failure risk over 13 years with use of basiliximab (adjusted hazard ratio [aHR], 0.86; confidence interval [CI], 0.68-1.08), Thymoglobulin (aHR, 0.92; CI, 0.7-1.21) or alemtuzumab (aHR, 1.18; CI, 0.72-1.93). Among induction-free recipients at the center, calcineurin inhibitor withdrawal at 1 year (n = 27) did not significantly impact graft failure risk (HR,1.62; CI, 0.38-6.89). This study may serve as a foundation for further studies to provide personalized, tailored, immunosuppression for this very low-risk population of kidney transplant patients.

Calcineurin Orchestrates Lateral Transfer of Aspergillus fumigatus during Macrophage Cell Death.

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Shah, Anand; Kannambath, Shichina; Herbst, Susanne; Rogers, Andrew; Soresi, Simona; Carby, Martin; Reed, Anna; Mostowy, Serge; Fisher, Matthew C; Shaunak, Sunil; Armstrong-James, Darius P

2016-11-01

Pulmonary aspergillosis is a lethal mold infection in the immunocompromised host. Understanding initial control of infection and how this is altered in the immunocompromised host are key goals for comprehension of the pathogenesis of pulmonary aspergillosis. To characterize the outcome of human macrophage infection with Aspergillus fumigatus and how this is altered in transplant recipients on calcineurin inhibitor immunosuppressants. We defined the outcome of human macrophage infection with A. fumigatus, as well as the impact of calcineurin inhibitors, through a combination of single-cell fluorescence imaging, transcriptomics, proteomics, and in vivo studies. Macrophage phagocytosis of A. fumigatus enabled control of 90% of fungal germination. However, fungal germination in the late phagosome led to macrophage necrosis. During programmed necroptosis, we observed frequent cell-cell transfer of A. fumigatus between macrophages, which assists subsequent control of germination in recipient macrophages. Lateral transfer occurred through actin-dependent exocytosis of the late endosome in a vasodilator-stimulated phosphoprotein envelope. Its relevance to the control of fungal germination was also shown by direct visualization in our zebrafish aspergillosis model in vivo. The calcineurin inhibitor FK506 (tacrolimus) reduced cell death and lateral transfer in vitro by 50%. This resulted in uncontrolled fungal germination in macrophages and also resulted in hyphal escape. These observations identify programmed, necrosis-dependent lateral transfer of A. fumigatus between macrophages as an important host strategy for controlling fungal germination. This process is critically dependent on calcineurin. Our studies provide fundamental insights into the pathogenesis of pulmonary aspergillosis in the immunocompromised host.

FKBP12-Dependent Inhibition of Calcineurin Mediates Immunosuppressive Antifungal Drug Action in Malassezia

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Giuseppe Ianiri

2017-10-01

Full Text Available The genus Malassezia includes yeasts that are commonly found on the skin or hair of animals and humans as commensals and are associated with a number of skin disorders. We have previously developed an Agrobacterium tumefaciens transformation system effective for both targeted gene deletion and insertional mutagenesis in Malassezia furfur and M. sympodialis. In the present study, these molecular resources were applied to characterize the immunophilin FKBP12 as the target of tacrolimus (FK506, ascomycin, and pimecrolimus, which are calcineurin inhibitors that are used as alternatives to corticosteroids in the treatment of inflammatory skin disorders such as those associated with Malassezia species. While M. furfur and M. sympodialis showed in vitro sensitivity to these agents, fkb1Δ mutants displayed full resistance to all three of them, confirming that FKBP12 is the target of these calcineurin inhibitors and is essential for their activity. We found that calcineurin inhibitors act additively with fluconazole through an FKBP12-dependent mechanism. Spontaneous M. sympodialis isolates resistant to calcineurin inhibitors had mutations in the gene encoding FKBP12 in regions predicted to affect the interactions between FKBP12 and FK506 based on structural modeling. Due to the presence of homopolymer nucleotide repeats in the gene encoding FKBP12, an msh2Δ hypermutator of M. sympodialis was engineered and exhibited an increase of more than 20-fold in the rate of emergence of resistance to FK506 compared to that of the wild-type strain, with the majority of the mutations found in these repeats.

Sperm calcineurin inhibition prevents mouse fertility with implications for male contraceptive.

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Miyata, Haruhiko; Satouh, Yuhkoh; Mashiko, Daisuke; Muto, Masanaga; Nozawa, Kaori; Shiba, Kogiku; Fujihara, Yoshitaka; Isotani, Ayako; Inaba, Kazuo; Ikawa, Masahito

2015-10-23

Calcineurin inhibitors, such as cyclosporine A and FK506, are used as immunosuppressant drugs, but their adverse effects on male reproductive function remain unclear. The testis expresses somatic calcineurin and a sperm-specific isoform that contains a catalytic subunit (PPP3CC) and a regulatory subunit (PPP3R2). We demonstrate herein that male mice lacking Ppp3cc or Ppp3r2 genes (knockout mice) are infertile, with reduced sperm motility owing to an inflexible midpiece. Treatment of mice with cyclosporine A or FK506 creates phenocopies of the sperm motility and morphological defects. These defects appear within 4 to 5 days of treatment, which indicates that sperm-specific calcineurin confers midpiece flexibility during epididymal transit. Male mouse fertility recovered a week after we discontinued treatment. Because human spermatozoa contain PPP3CC and PPP3R2 as a form of calcineurin, inhibition of this sperm-specific calcineurin may lead to the development of a reversible male contraceptive that would target spermatozoa in the epididymis. Copyright © 2015, American Association for the Advancement of Science.

Risk factors for calcineurin inhibitor nephrotoxicity after renal transplantation: a systematic review and meta-analysis

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Xia T

2018-02-01

Full Text Available Tianyi Xia, Sang Zhu, Yan Wen, Shouhong Gao, Mingming Li, Xia Tao, Feng Zhang, Wansheng Chen Department of Pharmacy, Changzheng Hospital, Second Military Medical University, Shanghai, People’s Republic of China Background: Nephrotoxicity of calcineurin inhibitors (CNIs is the major concern for long-term allograft survival despite its predominant role in current immunosuppressive regime after renal transplantation. CNI nephrotoxicity is multifactorial with demographic, environmental, and pharmacogenetic flexibility, whereas studies indicating risk factors for CNI nephrotoxicity obtained incomplete or conflicting results.Methods: A systematic review and meta-analysis of risk factors for CNI nephrotoxicity was performed on all retrieved studies through a comprehensive research of network database. Data were analyzed by Review Manager 5.2 with heterogeneity assessed using the Cochrane Q and I2 tests. CNI nephrotoxicity was primarily indicated with protocol biopsy or index-based clinical diagnosis, and the secondary outcome was defined as delayed graft function.Results: Twelve observational studies containing a total of 2,849 cases were identified. Donor age (odds ratio [OR], 1.01; 95% CI, 1.01–1.03; p=0.02, recipient zero-time arteriosclerosis (OR, 1.44; 95% CI, 1.04–1.99; p=0.03, and CYP3A5*3/*3 genotype (OR, 2.80; 95% CI, 2.63–2.98; p=0.00 were confirmed as risk factors for CNI nephrotoxicity. Subgroup and sensitivity analysis claimed donor age as a significant contributor in Asian and Caucasian areas.Conclusion: Older donor age, recipient zero-time arteriosclerosis, and CYP3A5*3/*3 genotype might add up the risk for CNI nephrotoxicity, which could be interpreted into a robust biomarker system. Keywords: calcineurin inhibitor, transplantation, nephrotoxicity, risk factor, systematic review, meta-analysis

24-h monitoring of calcineurin phosphatase activity in healthy subjects

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Koefoed-Nielsen, P.B.; Karamperis, N.; Jørgensen, Kaj Anker

2005-01-01

The calcineurin inhibitors cyclosporine and tacrolimus are the cornerstone immunosuppressants used in solid organ transplantation. Studies investigating calcineurin (CaN) activity in renal transplanted patients have been published, but basic properties of the enzyme activity in healthy subjects...... remain to be described. The aim of this study was to investigate whether CaN displays circadian variation or sex difference is present in healthy subjects. Twenty subjects had blood samples drawn every 4 h for a 24-h period. CaN activity was determined in whole blood as the release of 32P from...

Plasma NGAL and glomerular filtration rate in cardiac transplant recipients treated with standard or reduced calcineurin inhibitor levels

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Gustafsson, Finn; Gude, Einar; Sigurdardottir, Vilborg

2014-01-01

GFR) at baseline (R(2) = 0.21; p year (median [25-75 % percentiles]: ΔmGFR 5.5 [-0.5-11.5] vs -1 [-7-4] ml/min/1.73 m(2); p = 0.006). Baseline P-NGAL predicted mGFR after 1 year (R(2) = 0.18; p ...: P-NGAL was measured in 88 cardiac transplantation patients (median 5 years post-transplant) with renal dysfunction randomized to continuation of conventional calcineurin inhibitor-based immunosuppression or switching to an everolimus-based regimen. RESULTS: P-NGAL correlated with measured GFR (m...

Calcineurin inhibitors acutely improve insulin sensitivity without affecting insulin secretion in healthy human volunteers

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Øzbay, Aygen; Møller, Niels; Juhl, Claus

2012-01-01

and tacrolimus has been attributed to both beta cell dysfunction and impaired insulin sensitivity. WHAT THIS STUDY ADDS: This is the first trial to investigate beta cell function and insulin sensitivity using gold standard methodology in healthy human volunteers treated with clinically relevant doses...... of ciclosporin and tacrolimus. We document that both drugs acutely increase insulin sensitivity, while first phase and pulsatile insulin secretion remain unaffected. This study demonstrates that ciclosporin and tacrolimus have similar acute effects on glucose metabolism in healthy humans. AIM The introduction...... of calcineurin inhibitors (CNIs) ciclosporin (CsA) and tacrolimus (Tac) has improved the outcome of organ transplants, but complications such as new onset diabetes mellitus after transplantation (NODAT) cause impairment of survival rates. The relative contribution of each CNI to the pathogenesis and development...

Campath, calcineurin inhibitor reduction and chronic allograft nephropathy (3C) study: background, rationale, and study protocol

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2013-01-01

Background Kidney transplantation is the best treatment for patients with end-stage renal failure, but uncertainty remains about the best immunosuppression strategy. Long-term graft survival has not improved substantially, and one possible explanation is calcineurin inhibitor (CNI) nephrotoxicity. CNI exposure could be minimized by using more potent induction therapy or alternative maintenance therapy to remove CNIs completely. However, the safety and efficacy of such strategies are unknown. Methods/Design The Campath, Calcineurin inhibitor reduction and Chronic allograft nephropathy (3C) Study is a multicentre, open-label, randomized controlled trial with 852 participants which is addressing two important questions in kidney transplantation. The first question is whether a Campath (alemtuzumab)-based induction therapy strategy is superior to basiliximab-based therapy, and the second is whether, from 6 months after transplantation, a sirolimus-based maintenance therapy strategy is superior to tacrolimus-based therapy. Recruitment is complete, and follow-up will continue for around 5 years post-transplant. The primary endpoint for the induction therapy comparison is biopsy-proven acute rejection by 6 months, and the primary endpoint for the maintenance therapy comparison is change in estimated glomerular filtration rate from baseline to 2 years after transplantation. The study is sponsored by the University of Oxford and endorsed by the British Transplantation Society, and 18 centers for adult kidney transplant are participating. Discussion Late graft failure is a major issue for kidney-transplant recipients. If our hypothesis that minimizing CNI exposure with Campath-based induction therapy and/or an elective conversion to sirolimus-based maintenance therapy can improve long-term graft function and survival is correct, then patients should experience better graft function for longer. A positive outcome could change clinical practice in kidney transplantation. Trial

Activation of the Ca2+/calcineurin/NFAT2 pathway controls smooth muscle cell differentiation

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Larrieu, Daniel; Thiebaud, Pierre; Duplaa, Cecile; Sibon, Igor; Theze, Nadine; Lamaziere, Jean-Marie Daniel

2005-01-01

Cellular mechanisms controlling smooth muscle cells (SMCs) phenotypic modulation are largely unknown. Intracellular Ca 2+ movements are essential to ensure SMC functions; one of the roles of Ca 2+ is to regulate calcineurin, which in turn induces nuclear localization of the nuclear factor of activated T-cell (NFAT). In order to investigate, during phenotypic differentiation of SMCs, the effect of calcineurin inhibition on NFAT 2 nuclear translocation, we used a culture model of SMC differentiation in serum-free conditions. We show that the treatment of cultured SMC with the calcineurin inhibitor cyclosporine A induced their dedifferentiation while preventing their differentiation. These findings suggest that nuclear translocation of NFAT 2 is dependent of calcineurin activity during the in vitro SMC differentiation kinetic and that the nuclear presence of NFAT 2 is critical in the acquisition and maintenance of SMC differentiation

Defibrotide Stimulates Angiogenesis and Protects Endothelial Cells from Calcineurin Inhibitor-Induced Apoptosis via Upregulation of AKT/Bcl-xL.

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Wang, Xiangmin; Pan, Bin; Hashimoto, Yuko; Ohkawara, Hiroshi; Xu, Kailin; Zeng, Lingyu; Ikezoe, Takayuki

2018-01-01

Sinusoidal obstruction syndrome is a life-threatening complication that can occur after haematopoietic stem cell transplantation. Defibrotide (DF) has been approved for the treatment of individuals with severe sinusoidal obstruction syndrome following haematopoietic stem cell transplantation in the European Union and the United States. However, the precise mechanisms by which DF protects endothelial cells remain to be elucidated. In this study, we found that DF stimulated angiogenesis in vitro and in vivo as assessed by vascular tube formation, scratch-wound repair and Matrigel plug assays. These effects were associated with an activation of pro-survival signalling pathways, including AKT (protein kinase B), ERK (extracellular signal-regulated kinases) and p38. More importantly, DF alleviated calcineurin inhibitor-induced growth inhibition and apoptosis of human umbilical vein endothelial cells and human hepatic sinusoidal endothelial cells in parallel with upregulation of anti-apoptotic protein B-cell lymphoma-extra-large (Bcl-xL), which was mediated by AKT (protein kinase B). Notably, these effects were abrogated when Bcl-xL was depleted by small interfering RNA (ribonucleic acid). In addition, DF counteracted calcineurin inhibitor-induced activation of nuclear factor-κB and Janus kinase 2 (JAK2)/Signal Transducer and Activator of Transcription 3 (STAT3) signalling and production of cytokines in vascular endothelial cell-derived EA.hy926 cells. Taken together, DF has pro-angiogenic, anti-apoptotic and anti-inflammatory effects on endothelial cells. DF is a potentially useful agent to prevent the development of, and treat individuals with, endothelial cell injury-related complications after haematopoietic stem cell transplantation. Schattauer GmbH Stuttgart.

Increased calcineurin expression after pilocarpine-induced status epilepticus is associated with brain focal edema and astrogliosis.

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Liu, Jinzhi; Li, Xiaolin; Chen, Liguang; Xue, Ping; Yang, Qianqian; Wang, Aihua

2015-07-28

Calcineurin plays an important role in the development of neuronal excitability, modulation of receptor's function and induction of apoptosis in neurons. It has been established in kindling models that status epilepticus induces brain focal edema and astrocyte activation. However, the role of calcineurin in brain focal edema and astrocyte activation in status epilepticus has not been fully understood. In this study, we employed a model of lithium-pilocarpine-induced status epilepticus and detected calcineurin expression in hippocampus by immunoblotting, brain focal edema by non-invasive magnetic resonance imaging (MRI-7T) and astrocyte expression by immunohistochemistry. We found that the brain focal edema was seen at 24 h after status epilepticus, and astrocyte expression was obviously seen at 7 d after status epilepticus. Meanwhile, calcineurin expression was seen at24 h and retained to 7 d after status epilepticus. A FK506, a calcineurin inhibitor, remarkably suppressed the status epilepticus-induced brain focal edema and astrocyte expression. Our data suggested that calcineurin overexpression plays a very important role in brain focal edema and astrocyte expression. Therefore, calcineurin may be a novel candidate for brain focal edema occurring and intracellular trigger of astrogliosis in status epilepticus.

Calcineurin plays key roles in the dimorphic transition and virulence of the human pathogenic zygomycete Mucor circinelloides.

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Lee, Soo Chan; Li, Alicia; Calo, Silvia; Heitman, Joseph

2013-01-01

Many pathogenic fungi are dimorphic and switch between yeast and filamentous states. This switch alters host-microbe interactions and is critical for pathogenicity. However, in zygomycetes, whether dimorphism contributes to virulence is a central unanswered question. The pathogenic zygomycete Mucor circinelloides exhibits hyphal growth in aerobic conditions but switches to multi-budded yeast growth under anaerobic/high CO₂ conditions. We found that in the presence of the calcineurin inhibitor FK506, Mucor exhibits exclusively multi-budded yeast growth. We also found that M. circinelloides encodes three calcineurin catalytic A subunits (CnaA, CnaB, and CnaC) and one calcineurin regulatory B subunit (CnbR). Mutations in the latch region of CnbR and in the FKBP12-FK506 binding domain of CnaA result in hyphal growth of Mucor in the presence of FK506. Disruption of the cnbR gene encoding the sole calcineurin B subunit necessary for calcineurin activity yielded mutants locked in permanent yeast phase growth. These findings reveal that the calcineurin pathway plays key roles in the dimorphic transition from yeast to hyphae. The cnbR yeast-locked mutants are less virulent than the wild-type strain in a heterologous host system, providing evidence that hyphae or the yeast-hyphal transition are linked to virulence. Protein kinase A activity (PKA) is elevated during yeast growth under anaerobic conditions, in the presence of FK506, or in the yeast-locked cnbR mutants, suggesting a novel connection between PKA and calcineurin. cnaA mutants lacking the CnaA catalytic subunit are hypersensitive to calcineurin inhibitors, display a hyphal polarity defect, and produce a mixture of yeast and hyphae in aerobic culture. The cnaA mutants also produce spores that are larger than wild-type, and spore size is correlated with virulence potential. Our results demonstrate that the calcineurin pathway orchestrates the yeast-hyphal and spore size dimorphic transitions that contribute to

The calcineurin pathway inhibitor tacrolimus enhances the in vitro activity of azoles against Mucorales via apoptosis.

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Shirazi, F; Kontoyiannis, D P

2013-09-01

The calcineurin pathway regulates antifungal drug resistance and the virulence of several major human-pathogenic fungi, including the recalcitrant Mucorales. We hypothesized that the fungistatic triazoles posaconazole (PCZ) and itraconazole (ICZ) become fungicidal in the setting of the calcineurin inhibitor tacrolimus (TCR) and that such an effect is mediated through apoptosis. Fungicidal activity and apoptosis were studied using standard microbiological techniques and hyphal metabolic and vital dye reduction assays at 37°C in RPMI 1640. Apoptosis was characterized by detecting intracellular Ca(2+), phosphatidylserine (PS) externalization, DNA fragmentation, plasma membrane integrity, chromatin condensation, reactive oxygen species (ROS) generation, caspase-like activity, ATP, and cytochrome c release. MICs for PCZ and ICZ alone were significantly higher (8 to 128 μg/ml) than those of PCZ or ICZ plus TCR (0.25 to 4 μg/ml) for Rhizopus oryzae, Cunninghamella bertholletiae, and Mucor circinelloides. Both PCZ and ICZ in combination with TCR became fungicidal, and their activity was mediated through increased apoptotic cell death of R. oryzae (10 to 50%), C. bertholletiae (5 to 50%), and M. circinelloides (5 to 55%) germlings, with morphological apoptotic changes characterized by externalization of PS, nuclear condensation, and DNA fragmentation. Moreover, activation of the caspase-like activity was correlated with cell death induced by TCR plus PCZ or ICZ. These changes correlated with elevated intracellular Ca(2+) and ROS levels and disturbance of mitochondrial potential. We found that PCZ or ICZ in combination with TCR renders Mucorales sensitive to triazoles via apoptotic death. These observations could serve as a new paradigm for the development of new therapeutic strategies.

T-plastin expression downstream to the calcineurin/NFAT pathway is involved in keratinocyte migration.

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Cécilia Brun

migration. These results indicate that T-plastin might be considered as a major actor in the mechanisms underlying calcineurin/NFAT-dependent keratinocyte migration and may explain wound-healing defects observed in patients under calcineurin inhibitor long-term treatment.

Calcineurin inhibitors improve memory loss and neuropathological changes in mouse model of dementia.

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Kumar, Amit; Singh, Nirmal

2017-02-01

The present study was designed to investigate the potential of Cyclosporine (CsA) and Tacrolimus, the inhibitors of calcineurin (CaN) in cognitive deficits of mice. Streptozotocin [STZ, 3mg/kg, injected intracerebroventricular (i.c.v.)] was used to induce memory deficits in NIH mice, while aged mice separately taken served as a natural model of dementia. Morris water maze (MWM) test was employed to evaluate learning and memory of the animals. A battery of biochemical and histopathological studies was also performed. Extent of oxidative stress was measured by estimating the levels of brain glutathione (GSH) and thiobarbituric acid reactive species (TBARS). Brain acetylcholinestrase (AChE) activity was estimated to assess cholinergic activity. The brain level of myeloperoxidase (MPO) was measured as a marker of inflammation. STZ i.c.v. and aging results in marked decline in MWM performance of the animals, reflecting impairment of learning and memory. STZ i.c.v. treated mice and aged mice exhibited a marked accentuation of AChE activity, TBARS and MPO levels along with a fall in GSH level. Further the stained micrographs of STZ treated mice and aged mice indicate pathological changes, severe neutrophilic infiltration and amyloid deposition. Cyclosporine and Tacrolimus treatment significantly attenuated STZ induced and age related memory deficits, biochemical and histopathological alterations. The findings demonstrate the potential of CaN inhibitors Cyclosporine and Tacrolimus in memory dysfunctions which may probably be attributed to anti-cholinesterase, anti-amyloid, anti-oxidative and anti-inflammatory effects. It is concluded that CaN can be explored as a potential therapeutic target in dementia. Copyright © 2017 Elsevier Inc. All rights reserved.

Calcineurin Inhibitors in the Treatment of Primary Focal Segmental Glomerulosclerosis

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Louis-Philippe Laurin

2017-02-01

Full Text Available Purpose of review: Primary focal segmental glomerulosclerosis (FSGS is the most common cause of nephrotic syndrome in adults. Glucocorticoids have been evaluated in the treatment of primary FSGS in numerous retrospective studies. Evidence suggesting a role for including calcineurin inhibitors (CNIs in early therapy remains limited. The aim of this study was to systematically review the literature examining the efficacy of CNIs in the treatment of primary FSGS both as first-line therapy and as an adjunctive agent in steroid-resistant patients, with respect to remission in proteinuria and renal survival. Sources of information: PubMed and EMBASE were searched from inception to August 2014 for prospective controlled trials, and case-control and cohort studies. Findings: After systematically applying our inclusion criteria, a total of 152 titles and abstracts were identified. Six randomized controlled trials and 2 cohort studies were reviewed. Three randomized controlled trials compared CNIs with placebo or supportive therapy. The pooled relative “risk” of proteinuria remission associated with cyclosporine was 7.0 (95% confidence interval, 2.9-16.8 compared with placebo/supportive therapy. There was very low heterogeneity among these studies with an I -squared of 0%. Three studies compared CNIs with another immunosuppressive agent. All prospective trials were conducted in patients with primary FSGS deemed steroid-resistant. Limitations: The relatively small number of included studies and their heterogeneity with respect to treatment protocols, and possible publication bias, limit conclusions drawn from this systematic review. Implications: The efficacy of CNIs has been evaluated in steroid-resistant primary FSGS patients. There is no evidence supporting their role as first-line therapy. Further studies are needed to determine this role.

Calcineurin Targets Involved in Stress Survival and Fungal Virulence.

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Hee-Soo Park

2016-09-01

Full Text Available Calcineurin governs stress survival, sexual differentiation, and virulence of the human fungal pathogen Cryptococcus neoformans. Calcineurin is activated by increased Ca2+ levels caused by stress, and transduces signals by dephosphorylating protein substrates. Herein, we identified and characterized calcineurin substrates in C. neoformans by employing phosphoproteomic TiO2 enrichment and quantitative mass spectrometry. The identified targets include the transactivator Crz1 as well as novel substrates whose functions are linked to P-bodies/stress granules (PBs/SGs and mRNA translation and decay, such as Pbp1 and Puf4. We show that Crz1 is a bona fide calcineurin substrate, and Crz1 localization and transcriptional activity are controlled by calcineurin. We previously demonstrated that thermal and other stresses trigger calcineurin localization to PBs/SGs. Several calcineurin targets localized to PBs/SGs, including Puf4 and Pbp1, contribute to stress resistance and virulence individually or in conjunction with Crz1. Moreover, Pbp1 is also required for sexual development. Genetic epistasis analysis revealed that Crz1 and the novel targets Lhp1, Puf4, and Pbp1 function in a branched calcineurin pathway that orchestrates stress survival and virulence. These findings support a model whereby calcineurin controls stress and virulence, at the transcriptional level via Crz1, and post-transcriptionally by localizing to PBs/SGs and acting on targets involved in mRNA metabolism. The calcineurin targets identified in this study share little overlap with known calcineurin substrates, with the exception of Crz1. In particular, the mRNA binding proteins and PBs/SGs residents comprise a cohort of novel calcineurin targets that have not been previously linked to calcineurin in mammals or in Saccharomyces cerevisiae. This study suggests either extensive evolutionary rewiring of the calcineurin pathway, or alternatively that these novel calcineurin targets have yet

A therapeutic exploratory study to determine the efficacy and safety of calcineurin-inhibitor-free de-novo immunosuppression after liver transplantation: CILT

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Lorf Thomas

2010-04-01

Full Text Available Abstract Background Immunosuppression with calcineurin inhibitors (CNI increases the risk of renal dysfunction after orthotopic liver transplantation (OLT. Controlled trials have shown improvement of renal function in patients that received delayed and/or reduced-dose CNI after OLT. Delaying immunosuppression with CNI in combination with induction therapy does not increase the risk of acute rejection but reduces the incidence of acute renal dysfunction. Based on this clinical data this study protocol was designed to assess the efficacy and safety of calcineurin-inhibitor-free de-novo immunosuppression after liver transplantation. Methods/Design A prospective therapeutic exploratory, non-placebo controlled, two stage monocenter trial in a total of 29 liver transplant patients was designed to assess the safety and efficacy of de-novo CNI-free immunosuppression with basiliximab, mycophenolate sodium, prednisolone and everolimus. The primary endpoint is the rate of steroid resistant rejections. Secondary endpoints are the incidence of acute rejection, kidney function (assessed by incidence and duration of renal replacement therapy, incidence of chronic renal failure, and measurement glomerular filtration rate, liver allograft function (assessed by measurement of AST, ALT, total bilirubin, AP, GGT, treatment failure, (i. e., re-introduction of CNI, incidence of adverse events, and mortality up to one year after OLT. Discussion This prospective, two-stage, single-group pilot study represents an intermediate element of the research chain. If the data of the phase II study corroborates safety of de-novo CNI-free immunosuppressive regimen this should be confirmed in a randomized, prospective, controlled double-blinded clinical trial. The exploratory data from this trial may then also facilitate the design (e. g. sample size calculation of this phase III trial. Trial registration number NCT00890253 (clinicaltrials.gov

Calcineurin Orchestrates Lateral Transfer of Aspergillus fumigatus during Macrophage Cell Death

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Armstrong-James, DPH

2016-01-01

RATIONALE: Pulmonary aspergillosis is a lethal mould infection in the immunocompromised host. Understanding initial control of infection, and how this is altered in the immunocompromised host, is a key goal for understanding the pathogenesis of pulmonary aspergillosis. OBJECTIVES: To characterise the outcome of human macrophage infection with Aspergillus fumigatus, and how this is altered in transplant recipients on calcineurin inhibitor immunosuppressants. METHODS: We defined the outcome of ...

vph6 mutants of Saccharomyces cerevisiae require calcineurin for growth and are defective in vacuolar H(+)-ATPase assembly.

Science.gov (United States)

Hemenway, C S; Dolinski, K; Cardenas, M E; Hiller, M A; Jones, E W; Heitman, J

1995-11-01

We have characterized a Saccharomyces cerevisiae mutant strain that is hypersensitive to cyclosporin A (CsA) and FK506, immunosuppressants that inhibit calcineurin, a serine-threonine-specific phosphatase (PP2B). A single nuclear mutation, designated cev1 for calcineurin essential for viability, is responsible for the CsA-FK506-sensitive phenotype. The peptidyl-prolyl cis-trans isomerases cyclophilin A and FKBP12, respectively, mediate CsA and FK506 toxicity in the cev1 mutant strain. We demonstrate that cev1 is an allele of the VPH6 gene and that vph6 mutant strains fail to assemble the vacuolar H(+)-ATPase (V-ATPase). The VPH6 gene was mapped on chromosome VIII and is predicted to encode a 181-amino acid (21 kD) protein with no identity to other known proteins. We find that calcineurin is essential for viability in many mutant strains with defects in V-ATPase function or vacuolar acidification. In addition, we find that calcineurin modulates extracellular acidification in response to glucose, which we propose occurs via calcineurin regulation of the plasma membrane H(+)-ATPase PMA1. Taken together, our findings suggest calcineurin plays a general role in the regulation of cation transport and homeostasis.

The Emerging Roles of the Calcineurin-Nuclear Factor of Activated T-Lymphocytes Pathway in Nervous System Functions and Diseases

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Maulilio John Kipanyula

2016-01-01

Full Text Available The ongoing epidemics of metabolic diseases and increase in the older population have increased the incidences of neurodegenerative diseases. Evidence from murine and cell line models has implicated calcineurin-nuclear factor of activated T-lymphocytes (NFAT signaling pathway, a Ca2+/calmodulin-dependent major proinflammatory pathway, in the pathogenesis of these diseases. Neurotoxins such as amyloid-β, tau protein, and α-synuclein trigger abnormal calcineurin/NFAT signaling activities. Additionally increased activities of endogenous regulators of calcineurin like plasma membrane Ca2+-ATPase (PMCA and regulator of calcineurin 1 (RCAN1 also cause neuronal and glial loss and related functional alterations, in neurodegenerative diseases, psychotic disorders, epilepsy, and traumatic brain and spinal cord injuries. Treatment with calcineurin/NFAT inhibitors induces some degree of neuroprotection and decreased reactive gliosis in the central and peripheral nervous system. In this paper, we summarize and discuss the current understanding of the roles of calcineurin/NFAT signaling in physiology and pathologies of the adult and developing nervous system, with an emphasis on recent reports and cutting-edge findings. Calcineurin/NFAT signaling is known for its critical roles in the developing and adult nervous system. Its role in physiological and pathological processes is still controversial. However, available data suggest that its beneficial and detrimental effects are context-dependent. In view of recent reports calcineurin/NFAT signaling is likely to serve as a potential therapeutic target for neurodegenerative diseases and conditions. This review further highlights the need to characterize better all factors determining the outcome of calcineurin/NFAT signaling in diseases and the downstream targets mediating the beneficial and detrimental effects.

ELEVATE: an innovative study design to assess the efficacy, safety, and evolution of cardiovascular parameters in de novo kidney transplant recipients after early conversion from a calcineurin inhibitor to everolimus

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van der Giet M

2014-03-01

Full Text Available Markus van der Giet,1 Josep M Cruzado,2 Johan W de Fijter,3 Hallvard Holdaas,4 Zailong Wang,5 Antonio Speziale,6 Guido Junge61Department of Nephrology, Campus Benjamin Franklin, Charite'-Universitätsmedizin, Berlin, Germany; 2Department of Nephrology, University Hospital of Bellvitge, L'Hospitalet de Llobregat, Barcelona, Spain; 3Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands; 4Section of Nephrology, Department of Transplant Medicine, Oslo University Hospital, Rikshospitalet, Oslo, Norway; 5Biometrics and Statistical Science, Novartis Pharmaceuticals, East Hanover, NJ, USA; 6Research and Development, Novartis Pharma AG, Basel, SwitzerlandAbstract: Progressive decline in allograft function and cardiovascular mortality after kidney transplantation remain major clinical challenges that can potentially be addressed by the mammalian target of rapamycin (mTOR inhibitors, everolimus and sirolimus. mTOR inhibitors maintain immunosuppressive efficacy after minimization of calcineurin inhibitor (CNI therapy and can achieve significant long-term improvements in renal function. Recently, data have accumulated that suggest mTOR inhibitors may offer cardioprotective effects. In animal models, inhibition of mTOR leads to regression of cardiac hypertrophy, and the limited data consistently point to a remodeling benefit following heart transplantation. Experimentally, mTOR inhibitors restrict atherogenesis, confirmed clinically by intravascular ultrasound data demonstrating lower rates of transplant vasculopathy in heart transplant recipients on everolimus. Lastly, mTOR inhibitors appear to ameliorate arterial stiffness, a known risk factor for post-transplant cardiovascular events, but data remain sparse. The ELEVATE study will examine the renal effect of early conversion from CNI therapy to everolimus after kidney transplantation. Key secondary endpoints include the change in left ventricular mass index, the first time

Hsp90 governs echinocandin resistance in the pathogenic yeast Candida albicans via calcineurin.

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Sheena D Singh

2009-07-01

Full Text Available Candida albicans is the leading fungal pathogen of humans, causing life-threatening disease in immunocompromised individuals. Treatment of candidiasis is hampered by the limited number of antifungal drugs whose efficacy is compromised by host toxicity, fungistatic activity, and the emergence of drug resistance. We previously established that the molecular chaperone Hsp90, which regulates the form and function of diverse client proteins, potentiates resistance to the azoles in C. albicans and in the model yeast Saccharomyces cerevisiae. Genetic studies in S. cerevisiae revealed that Hsp90's role in azole resistance is to enable crucial cellular responses to the membrane stress exerted by azoles via the client protein calcineurin. Here, we demonstrate that Hsp90 governs cellular circuitry required for resistance to the only new class of antifungals to reach the clinic in decades, the echinocandins, which inhibit biosynthesis of a critical component of the fungal cell wall. Pharmacological or genetic impairment of Hsp90 function reduced tolerance of C. albicans laboratory strains and resistance of clinical isolates to the echinocandins and created a fungicidal combination. Compromising calcineurin function phenocopied compromising Hsp90 function. We established that calcineurin is an Hsp90 client protein in C. albicans: reciprocal co-immunoprecipitation validated physical interaction; Hsp90 inhibition blocked calcineurin activation; and calcineurin levels were depleted upon genetic reduction of Hsp90. The downstream effector of calcineurin, Crz1, played a partial role in mediating calcineurin-dependent stress responses activated by echinocandins. Hsp90's role in echinocandin resistance has therapeutic potential given that genetic compromise of C. albicans HSP90 expression enhanced the efficacy of an echinocandin in a murine model of disseminated candidiasis. Our results identify the first Hsp90 client protein in C. albicans, establish an entirely

Isoflurane induced cognitive impairment in aged rats through hippocampal calcineurin/NFAT signaling

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Ni, Cheng; Li, Zhengqian; Qian, Min; Zhou, Yang; Wang, Jun; Guo, Xiangyang, E-mail: puthmzk@163.com

2015-05-15

Calcineurin (CaN) over-activation constrains synaptic plasticity and memory formation. Upon CaN activation, NFAT imports into the nucleus and guides its downstream genes, which also affect neuronal and synaptic function. Aberrant CaN/NFAT signaling involves in neurotoxicity and cognitive impairment in neurological disorders such as Alzheimer's disease, but its role in postoperative cognitive dysfunction (POCD) remains uninvestigated. Inhaled anesthetic isoflurane facilitates the development of POCD, and the present study investigated the role of CaN/NFAT signaling in isoflurane induced cognitive impairment of aged rats, and the therapeutic effects of CaN inhibitor cyclosporine A (CsA). The results indicated that hippocampal CaN activity increased and peaked at 6 h after isoflurane exposure, and NFAT, especially NFATc4, imported into the nucleus following CaN activation. Furthermore, phamacological inhibition of CaN by CsA markedly attenuated isoflurane induced aberrant CaN/NFATc4 signaling in the hippocampus, and rescued relevant spatial learning and memory impairment of aged rats. Overall, the study suggests hippocampal CaN/NFAT signaling as the upstream mechanism of isoflurane induced cognitive impairment, and provides potential therapeutic target and possible treatment methods for POCD. - Highlights: • Isoflurane induces hippocampal calcineurin activation. • Isoflurane induces hippocampal NFAT, especially NFATc4, nuclear import. • Cyclosporine A attenuates isoflurane induced aberrant calcineurin/NFAT signaling. • Cyclosporine A rescues isoflurane induced cognitive impairment. • Calcineurin/NFAT signaling is the upstream mechanism of isoflurane induced synaptic dysfunction and cognitive impairment.

Isoflurane induced cognitive impairment in aged rats through hippocampal calcineurin/NFAT signaling

International Nuclear Information System (INIS)

Ni, Cheng; Li, Zhengqian; Qian, Min; Zhou, Yang; Wang, Jun; Guo, Xiangyang

2015-01-01

Calcineurin (CaN) over-activation constrains synaptic plasticity and memory formation. Upon CaN activation, NFAT imports into the nucleus and guides its downstream genes, which also affect neuronal and synaptic function. Aberrant CaN/NFAT signaling involves in neurotoxicity and cognitive impairment in neurological disorders such as Alzheimer's disease, but its role in postoperative cognitive dysfunction (POCD) remains uninvestigated. Inhaled anesthetic isoflurane facilitates the development of POCD, and the present study investigated the role of CaN/NFAT signaling in isoflurane induced cognitive impairment of aged rats, and the therapeutic effects of CaN inhibitor cyclosporine A (CsA). The results indicated that hippocampal CaN activity increased and peaked at 6 h after isoflurane exposure, and NFAT, especially NFATc4, imported into the nucleus following CaN activation. Furthermore, phamacological inhibition of CaN by CsA markedly attenuated isoflurane induced aberrant CaN/NFATc4 signaling in the hippocampus, and rescued relevant spatial learning and memory impairment of aged rats. Overall, the study suggests hippocampal CaN/NFAT signaling as the upstream mechanism of isoflurane induced cognitive impairment, and provides potential therapeutic target and possible treatment methods for POCD. - Highlights: • Isoflurane induces hippocampal calcineurin activation. • Isoflurane induces hippocampal NFAT, especially NFATc4, nuclear import. • Cyclosporine A attenuates isoflurane induced aberrant calcineurin/NFAT signaling. • Cyclosporine A rescues isoflurane induced cognitive impairment. • Calcineurin/NFAT signaling is the upstream mechanism of isoflurane induced synaptic dysfunction and cognitive impairment

Vph6 Mutants of Saccharomyces Cerevisiae Require Calcineurin for Growth and Are Defective in Vacuolar H(+)-Atpase Assembly

OpenAIRE

Hemenway, C. S.; Dolinski, K.; Cardenas, M. E.; Hiller, M. A.; Jones, E. W.; Heitman, J.

1995-01-01

We have characterized a Saccharomyces cerevisiae mutant strain that is hypersensitive to cyclosporin A (CsA) and FK506, immunosuppressants that inhibit calcineurin, a serine-threonine-specific phosphatase (PP2B). A single nuclear mutation, designated cev1 for calcineurin essential for viability, is responsible for the CsA-FK506-sensitive phenotype. The peptidyl-prolyl cis-trans isomerases cyclophilin A and FKBP12, respectively, mediate CsA and FK506 toxicity in the cev1 mutant strain. We demo...

Renal function in heart transplant patients after switch to combined mammalian target of rapamycin inhibitor and calcineurin inhibitor therapy

Directory of Open Access Journals (Sweden)

Helmschrott M

2017-06-01

Full Text Available Matthias Helmschrott,1 Rasmus Rivinius,1 Thomas Bruckner,2 Hugo A Katus,1 Andreas O Doesch1 1Department of Cardiology, Angiology, Pneumology, 2Institute for Medical Biometry and Informatics, University of Heidelberg, Heidelberg, Germany Background: A calcineurin inhibitor (CNI-based immunosuppression combined with mammalian target of rapamycin inhibitors (mTORs seems to be attractive in patients after heart transplantation (HTX in special clinical situations, for example, in patients with adverse drug effects of prior immunosuppression. Previous studies in patients after HTX detected advantageous effects regarding renal function of a tacrolimus (TAC-based vs cyclosporine-A (CSA-based immunosuppression (in combination with mycophenolate mofetil. However, data regarding renal function after HTX in mTOR/CNI patients remain limited. Aim: Primary end point of the present study was to analyze renal function in HTX patients 1 year after switch to an mTOR/CNI-based immunosuppression. Methods: Data of 80 HTX patients after change to mTOR/CNI-based immunosuppression were retrospectively analyzed. Renal function was assessed by measured serum creatinine and by estimated glomerular filtration rate (eGFR calculated from Modification of Diet in Renal Disease equation. Results: Twenty-nine patients received mTOR/CSA-based treatment and 51 patients received mTOR/TAC-based therapy. At time of switch and at 1-year follow-up, serum creatinine and eGFR did not differ significantly between both study groups (all P=not statistically significant. Analysis of variances with repeated measurements detected a similar change of renal function in both study groups. Conclusion: The present study detected no significant differences between both mTOR/CNI study groups, indicating a steady state of renal function in HTX patients after switch of immunosuppressive regimen. Keywords: heart transplantation, cyclosporine A, tacrolimus, risk factors

Regulation of ITAM adaptor molecules and their receptors by inhibition of calcineurin-NFAT signalling during late stage osteoclast differentiation

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Zawawi, M.S.F. [Universiti Sains Malaysia (USM) (Malaysia); Discipline of Anatomy and Pathology, School of Medical Sciences, University of Adelaide, Adelaide, SA 5005 (Australia); Dharmapatni, A.A.S.S.K.; Cantley, M.D. [Discipline of Anatomy and Pathology, School of Medical Sciences, University of Adelaide, Adelaide, SA 5005 (Australia); McHugh, K.P. [University of Florida, College of Dentistry, Fl (United States); Haynes, D.R. [Discipline of Anatomy and Pathology, School of Medical Sciences, University of Adelaide, Adelaide, SA 5005 (Australia); Crotti, T.N., E-mail: tania.crotti@adelaide.edu.au [Discipline of Anatomy and Pathology, School of Medical Sciences, University of Adelaide, Adelaide, SA 5005 (Australia)

2012-10-19

Highlights: Black-Right-Pointing-Pointer Calcineurin/NFAT inhibitors FK506 and VIVIT treated human PBMC derived osteoclasts in vitro. Black-Right-Pointing-Pointer Differential regulation of ITAM receptors and adaptor molecules by calcineurin/NFAT inhibitors. Black-Right-Pointing-Pointer FK506 and VIVIT suppress ITAM factors during late phase osteoclast differentiation. -- Abstract: Osteoclasts are specialised bone resorptive cells responsible for both physiological and pathological bone loss. Osteoclast differentiation and activity is dependent upon receptor activator NF-kappa-B ligand (RANKL) interacting with its receptor RANK to induce the transcription factor, nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 1 (NFATc1). The immunoreceptor tyrosine-based activation motif (ITAM)-dependent pathway has been identified as a co-stimulatory pathway in osteoclasts. Osteoclast-associated receptor (OSCAR) and triggering receptor expressed in myeloid cells (TREM2) are essential receptors that pair with adaptor molecules Fc receptor common gamma chain (FcR{gamma}) and DNAX-activating protein 12 kDa (DAP12) respectively to induce calcium signalling. Treatment with calcineurin-NFAT inhibitors, Tacrolimus (FK506) and the 11R-VIVIT (VIVIT) peptide, reduces NFATc1 expression consistent with a reduction in osteoclast differentiation and activity. This study aimed to investigate the effects of inhibiting calcineurin-NFAT signalling on the expression of ITAM factors and late stage osteoclast genes including cathepsin K (CathK), Beta 3 integrin ({beta}3) and Annexin VIII (AnnVIII). Human peripheral blood mononuclear cells (PBMCs) were differentiated with RANKL and macrophage-colony stimulating factor (M-CSF) over 10 days in the presence or absence of FK506 or VIVIT. Osteoclast formation (as assessed by tartrate resistant acid phosphatase (TRAP)) and activity (assessed by dentine pit resorption) were significantly reduced with treatment. Quantitative real

Delineation of the calcineurin-interacting region of cyclophilin B.

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Carpentier, M; Allain, F; Haendler, B; Slomianny, M C; Spik, G

2000-12-01

The immunosuppressant drug cyclosporin A (CsA) inhibits T-cell function by blocking the phosphatase activity of calcineurin. This effect is mediated by formation of a complex between the drug and cyclophilin (CyP), which creates a composite surface able to make high-affinity contacts with calcineurin. In vitro, the CyPB/CsA complex is more effective in inhibiting calcineurin than the CyPA/CsA and CyPC/CsA complexes, pointing to fine structural differences in the calcineurin-binding region. To delineate the calcineurin-binding region of CyPB, we mutated several amino acids, located in two loops corresponding to CyPA regions known to be involved, as follows: R76A, G77H, D155R, and D158R. Compared to wild-type CyPB, the G77H, D155R, and D158R mutants had intact isomerase and CsA-binding activities, indicating that no major conformational changes had taken place. When complexed to CsA, they all displayed only reduced affinity for calcineurin and much decreased inhibition of calcineurin phosphatase activity. These results strongly suggest that the three amino acids G77, D155, and D158 are directly involved in the interaction of CyPB/CsA with calcineurin, in agreement with their exposed position. The G77, D155, and D158 residues are not maintained in CyPA and might therefore account for the higher affinity of the CyPB/CsA complex for calcineurin.

Renal impairment after liver transplantation - a pilot trial of calcineurin inhibitor-free vs. calcineurin inhibitor sparing immunosuppression in patients with mildly impaired renal function after liver transplantation

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Gerhardt T

2009-05-01

Full Text Available Abstract Objectives Chronic kidney disease is frequent in patients after orthotopic liver transplantation (OLT and has impact on survival. Patients receiving calcineurin inhibitors (CNI are at increased risk to develop impaired renal function. Early CNI reduction and concomitant use of mycophenolat mofetil (MMF has been shown to improve renal function. Methods The aim of this trial was to compare dose-reduced CNI/MMF versus CNI-free MMF/prednisone-based treatment in stable patients after OLT with respect to glomerular filtration rate (GFR. 21 patients [GFR 44.9 ± 9.9 mL/min/1.73 m2 measured by 99m-Tc-DTPA-clearance, serum creatinine (SCr 1.5 ± 0.42 mg/dL] were randomized either to exchange CNI for 10 mg prednisone (group 1; n = 8 or to receive CNI at 25% of the initial dose (group 2; n = 13 each in combination with 1000 mg MMF b.i.d. Results At month 12 mean SCr (-0.3 ± 0.4 mg/dL, p = 0.031 and GFR improved (8.6 ± 13.1 mL/min/1.73 m2, p = 0.015 in group 2 but remained unchanged in group 1. Main side effects were gastroinstestinal symptoms (14.3% and infections (4.8%. Two biopsy proven, steroid-responsive rejections occurred. In group 1 mean diastolic blood pressure (BP increased by 11 ± 22 mmHg (p = 0.03. Conclusions Reduced dose CNI in combination with MMF but not CNI-free-immunosuppression leads to improvement of GFR in patients with moderately elevated SCr levels after OLT. Addition of steroids resulted in increased diastolic blood pressure presumably counterbalancing the benefits of CNI withdrawal on renal function.

The neuropeptide catestatin promotes vascular smooth muscle cell proliferation through the Ca{sup 2+}-calcineurin-NFAT signaling pathway

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Guo, Xiaoxia [Department of Cardiology, People' s Hospital, Peking University, No. 11 South Avenue, Xi Zhi Men Xicheng District, Beijing 100044 (China); Zhou, Chunyan, E-mail: chunyanzhou@bjmu.edu.cn [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University, 38 Xueyuan Road, Haidian District, Beijing 100191 (China); Sun, Ningling, E-mail: nlsun@263.net [Department of Cardiology, People' s Hospital, Peking University, No. 11 South Avenue, Xi Zhi Men Xicheng District, Beijing 100044 (China)

2011-04-22

Highlights: {yields} Catestatin stimulates proliferation of vascular smooth muscle cells in a dose-dependent manner. {yields} Catestatin provokes sustained increase in intracellular Ca{sup 2+}. {yields} Catestatin produces increased activation of calcineurin and promotes NFATc1 translocation into the nucleus. -- Abstract: The Chromogranin A-derived neuropeptide catestatin is an endogenous nicotinic cholinergic antagonist that acts as a pleiotropic hormone. Since catestatin shares several functions with other members derived from the chromogranin/secretogranin protein family and other neuropeptides which exert proliferative effects on vascular smooth muscle cells (VSMCs), we therefore hypothesized that catestatin would regulate VSMC proliferation. The present study demonstrates that catestatin caused a dose-dependent induction of proliferation in rat aortic smooth muscle cells and furthermore evoked a sustained increase in intracellular calcium. This subsequently leaded to enhanced activation of the Ca{sup 2+}/calmodulin-dependent phosphatase, calcineurin and resulted in an activation of the Ca{sup 2+}-dependent transcription factor, nuclear factor of activated T cells (NFAT), initiating transcription of proliferative genes. In addition, cyclosporin A (CsA), a potent inhibitor of calcineurin, abrogated catestatin-mediated effect on VSMCs, indicating that the calcineurin-NFAT signaling is strongly required for catestatin-induced growth of VSMCs. The present study establishes catestatin as a novel proliferative cytokine on vascular smooth muscle cells and this effect is mediated by the Ca{sup 2+}-calcineurin-NFAT signaling pathway.

CMV and BKPyV Infections in Renal Transplant Recipients Receiving an mTOR Inhibitor-Based Regimen Versus a CNI-Based Regimen: A Systematic Review and Meta-Analysis of Randomized, Controlled Trials.

Science.gov (United States)

Mallat, Samir G; Tanios, Bassem Y; Itani, Houssam S; Lotfi, Tamara; McMullan, Ciaran; Gabardi, Steven; Akl, Elie A; Azzi, Jamil R

2017-08-07

The objective of this meta-analysis is to compare the incidences of cytomegalovirus and BK polyoma virus infections in renal transplant recipients receiving a mammalian target of rapamycin inhibitor (mTOR)-based regimen compared with a calcineurin inhibitor-based regimen. We conducted a comprehensive search for randomized, controlled trials up to January of 2016 addressing our objective. Other outcomes included acute rejection, graft loss, serious adverse events, proteinuria, wound-healing complications, and eGFR. Two review authors selected eligible studies, abstracted data, and assessed risk of bias. We assessed quality of evidence using the Grading of Recommendations Assessment, Development and Evaluation methodology. We included 28 randomized, controlled trials with 6211 participants classified into comparison 1: mTOR inhibitor versus calcineurin inhibitor and comparison 2: mTOR inhibitor plus reduced dose of calcineurin inhibitor versus regular dose of calcineurin inhibitor. Results showed decreased incidence of cytomegalovirus infection in mTOR inhibitor-based group in both comparison 1 (risk ratio, 0.54; 95% confidence interval, 0.41 to 0.72), with high quality of evidence, and comparison 2 (risk ratio, 0.43; 95% confidence interval, 0.24 to 0.80), with moderate quality of evidence. The available evidence neither confirmed nor ruled out a reduction of BK polyoma virus infection in mTOR inhibitor-based group in both comparisons. Secondary outcomes revealed more serious adverse events and acute rejections in mTOR inhibitor-based group in comparison 1 and no difference in comparison 2. There was no difference in graft loss in both comparisons. eGFR was higher in the mTOR inhibitor-based group in comparison 1 (mean difference =4.07 ml/min per 1.73 m 2 ; 95% confidence interval, 1.34 to 6.80) and similar to the calcineurin inhibitor-based group in comparison 2. More proteinuria and wound-healing complications occurred in the mTOR inhibitor-based groups. We found

Intermedilysin induces EGR-1 expression through calcineurin/NFAT pathway in human cholangiocellular carcinoma cells

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Susilowati, Heni [Department of Oral Microbiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8504 (Japan); Okamura, Hirohiko [Department of Histology and Oral Histology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8504 (Japan); Hirota, Katsuhiko, E-mail: hirota@dent.tokushima-u.ac.jp [Department of Oral Microbiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8504 (Japan); Shono, Masayuki [Support Center for Advanced Medical Sciences, The University of Tokushima, Tokushima 770-8504 (Japan); Yoshida, Kaya [Department of Fundamental Oral Health Science, School of Oral Health and Welfare, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8504 (Japan); Murakami, Keiji [Department of Oral Microbiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8504 (Japan); Tabata, Atsushi; Nagamune, Hideaki [Department of Biological Science and Technology, Life System, Institute of Technology and Science, The University of Tokushima Graduate School, Tokushima 770-8506 (Japan); Haneji, Tatsuji [Department of Histology and Oral Histology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8504 (Japan); Miyake, Yoichiro [Department of Oral Microbiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8504 (Japan)

2011-01-07

Research highlights: {yields} ILY leads to the accumulation of [Ca{sup 2+}]i in the nucleus in HuCCT1 cells. {yields} ILY induced activation of NFAT1 through a calcineurin-dependent pathway. {yields} Calcineuri/NFAT pathway is involved in EGR-1 expression in response to ILY treatment. -- Abstract: Intermedilysin (ILY) is a cholesterol-dependent cytolysin produced by Streptococcus intermedius, which is associated with human brain and liver abscesses. Although intrahepatic bile duct cells play a valuable role in the pathogenesis of liver abscess, the molecular mechanism of ILY-treated intrahepatic bile duct cells remains unknown. In this study, we report that ILY induced a nuclear accumulation of intracellular calcium ([Ca{sup 2+}]i) in human cholangiocellular cells HuCCT1. We also demonstrate that 10 ng/ml ILY induced NFAT1 dephosphorylation and its nuclear translocation in HuCCT1 cells. In contrast to the result that ILY induced NF-{kappa}B translocation in human hepatic HepG2 cells, ILY did not affect NF-{kappa}B localization in HuCCT1 cells. Dephosphorylation and nuclear translocation of NFAT1 caused by ILY were prevented by [Ca{sup 2+}]i calcium chelator, BAPTA/AM, and calcineurin inhibitors, cyclosporine A and tacrolimus. ILY induced early growth response-1 (EGR-1) expression and it was inhibited by the pre-treatment with cyclosporine A, indicating that the calcineurin/NFAT pathway was involved in EGR-1 expression in response to ILY. ILY-induced calcineurin/NFAT1 activation and sequential EGR-1 expression might be related to the pathogenesis of S. intermedius in human bile duct cells.

Intermedilysin induces EGR-1 expression through calcineurin/NFAT pathway in human cholangiocellular carcinoma cells

International Nuclear Information System (INIS)

Susilowati, Heni; Okamura, Hirohiko; Hirota, Katsuhiko; Shono, Masayuki; Yoshida, Kaya; Murakami, Keiji; Tabata, Atsushi; Nagamune, Hideaki; Haneji, Tatsuji; Miyake, Yoichiro

2011-01-01

Research highlights: → ILY leads to the accumulation of [Ca 2+ ]i in the nucleus in HuCCT1 cells. → ILY induced activation of NFAT1 through a calcineurin-dependent pathway. → Calcineuri/NFAT pathway is involved in EGR-1 expression in response to ILY treatment. -- Abstract: Intermedilysin (ILY) is a cholesterol-dependent cytolysin produced by Streptococcus intermedius, which is associated with human brain and liver abscesses. Although intrahepatic bile duct cells play a valuable role in the pathogenesis of liver abscess, the molecular mechanism of ILY-treated intrahepatic bile duct cells remains unknown. In this study, we report that ILY induced a nuclear accumulation of intracellular calcium ([Ca 2+ ]i) in human cholangiocellular cells HuCCT1. We also demonstrate that 10 ng/ml ILY induced NFAT1 dephosphorylation and its nuclear translocation in HuCCT1 cells. In contrast to the result that ILY induced NF-κB translocation in human hepatic HepG2 cells, ILY did not affect NF-κB localization in HuCCT1 cells. Dephosphorylation and nuclear translocation of NFAT1 caused by ILY were prevented by [Ca 2+ ]i calcium chelator, BAPTA/AM, and calcineurin inhibitors, cyclosporine A and tacrolimus. ILY induced early growth response-1 (EGR-1) expression and it was inhibited by the pre-treatment with cyclosporine A, indicating that the calcineurin/NFAT pathway was involved in EGR-1 expression in response to ILY. ILY-induced calcineurin/NFAT1 activation and sequential EGR-1 expression might be related to the pathogenesis of S. intermedius in human bile duct cells.

The impact of calcineurin inhibitors on neutrophil gelatinase-associated lipocalin and fibroblast growth factor 23 in long-term kidney transplant patients.

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Bleskestad, Inger Hjørdis; Thorsen, Inga Strand; Jonsson, Grete; Skadberg, Øyvind; Gøransson, Lasse Gunnar

2017-08-01

Neutrophil gelatinase-associated lipocalin (NGAL), a protein with bacteriostatic functions rapidly excreted from stimulated or damaged epithelial cells, is elevated in acute and chronic kidney disease. A calcineurin dependent signaling pathway for fibroblast growth factor 23 (FGF23) has been revealed, but the effect of calcineurin inhibitors (CNIs) on the levels of NGAL and markers of mineral metabolism in long-term kidney transplant patients has not been explored. In a cross-sectional study, 39 patients who received a first kidney transplant more than 10 years ago were split into two groups based on whether (n=28) or not (n=11) they used CNIs. Only patients with well-functioning grafts defined as an estimated glomerular filtration rate ≥45 mL/min per 1.73 m 2 were included. The median levels of NGAL, intact parathyroid hormone (iPTH), and iFGF23 were significantly higher in CNI users vs CNI nonusers, 167.0 (134.0-235.0) ng/mL vs 105.0 (91.3-117.0) ng/mL, P<.001, 13.8 (10.0-17.3) pmol/L vs 8.4 (6.4-9.9) pmol/L, P=.003, and 81.6 (56.4-116.5) pg/mL vs 61.8 (43.3-72.1) pg/mL, P=.04 respectively. The median levels of iFGF23 were higher in CNI users compared to CNI nonusers giving support to the notion of a CNI induced FGF23 resistance in the parathyroid. The net result of CNIs side effects needs to be further explored. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Performance investigation of low-toxic organic corrosion inhibitors in amine treating unit

International Nuclear Information System (INIS)

Veawab, A.; Tanthapanichakoon, W.

2003-01-01

Amine treating unit is constantly subject to severe corrosion problems leading to extra expenditure and operational limitations. Heavy-metal vanadium compounds are extensively used as corrosion inhibitors to suppress the severe corrosion to an acceptable level. In recent years, the fact that these vanadium compounds are inherently toxic and can potentially pose adverse impacts on the human health and the environment has brought about environmental awareness that causes their uses costly due to the difficulty in waste disposal. To respond to the environmental concern and reduce cost of waste disposal as well as prepare for more stringent regulations for chemical uses, the development of low-toxic corrosion inhibitors is necessary. This work therefore focuses on an investigation of inhibition performance of a number of organic and inorganic compounds that have relatively low toxicity in comparison with conventional inhibitors. The performance evaluation was carried out through corrosion experiments using carbon steel specimens. The experiments were done in 3 and 5 kmol/m 3 monoethanolamine (MEA) solution saturated with CO 2 at 80 o C. It was found that several tested compounds have potential to be effective low-toxic corrosion inhibitors. The promising compounds provide reasonable and in some cases comparable protection performance to the conventional inhibitor. (author)

Toxic agents causing cerebellar ataxias.

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Manto, Mario

2012-01-01

The cerebellum is particularly vulnerable to intoxication and poisoning, especially so the cerebellar cortex and Purkinje neurons. In humans, the most common cause of a toxic lesion to the cerebellar circuitry is alcohol related, but the cerebellum is also a main target of drug exposure (such as anticonvulsants, antineoplastics, lithium salts, calcineurin inhibitors), drug abuse and addiction (such as cocaine, heroin, phencyclidine), and environmental toxins (such as mercury, lead, manganese, toluene/benzene derivatives). Although data for the prevalence and incidence of cerebellar lesions related to intoxication and poisoning are still unknown in many cases, clinicians should keep in mind the list of agents that may cause cerebellar deficits, since toxin-induced cerebellar ataxias are not rare in daily practice. Moreover, the patient's status may require immediate therapies when the intoxication is life-threatening. 2012 Elsevier B.V. All rights reserved.

Calcineurin inhibitor-induced complement system activation via ERK1/2 signalling is inhibited by SOCS-3 in human renal tubule cells.

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Loeschenberger, Beatrix; Niess, Lea; Würzner, Reinhard; Schwelberger, Hubert; Eder, Iris E; Puhr, Martin; Guenther, Julia; Troppmair, Jakob; Rudnicki, Michael; Neuwirt, Hannes

2018-02-01

One factor that significantly contributes to renal allograft loss is chronic calcineurin inhibitor (CNI) nephrotoxicity (CIN). Among other factors, the complement (C-) system has been proposed to be involved CIN development. Hence, we investigated the impact of CNIs on intracellular signalling and the effects on the C-system in human renal tubule cells. In a qPCR array, CNI treatment upregulated C-factors and downregulated SOCS-3 and the complement inhibitors CD46 and CD55. Additionally, ERK1/-2 was required for these regulations. Following knock-down and overexpression of SOCS-3, we found that SOCS-3 inhibits ERK1/-2 signalling. Finally, we assessed terminal complement complex formation, cell viability and apoptosis. Terminal complement complex formation was induced by CNIs. Cell viability was significantly decreased, whereas apoptosis was increased. Both effects were reversed under complement component-depleted conditions. In vivo, increased ERK1/-2 phosphorylation and SOCS-3 downregulation were observed at the time of transplantation in renal allograft patients who developed a progressive decline of renal function in the follow-up compared to stable patients. The progressive cohort also had lower total C3 levels, suggesting higher complement activity at baseline. In conclusion, our data suggest that SOCS-3 inhibits CNI-induced ERK1/-2 signalling, thereby blunting the negative control of C-system activation. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Directions for use of corticosteroids and calcineurin inhibitors against generalized myasthenia gravis: therapeutic strategies that can lead to early improvements and veer away from high-dose oral corticosteroids].

Science.gov (United States)

Utsugisawa, Kimiaki; Nagane, Yuriko; Suzuki, Shigeaki; Suzuki, Norihiro

2012-01-01

The advent of effective immune treatment has meant that myasthenia gravis (MG) is most often not lethal. However, many MG patients still find it difficult to maintain daily activities due to chronic residual fatigability and long-term side effects of medication, since full remission without immune treatment is not common. Our analysis demonstrated that disease severity, dose of oral corticosteroids, and depressive state are the major independent factors negatively associated with self-reported QOL (MG-QOL15-J score). It is noteworthy that oral corticosteroid, the first-line agent for MG, is negatively associated with patients' QOL. When the analysis took into account MGFA postintervention status and dose of oral prednisolne (PSL), the MG-QOL15-J score of MM status patients taking ≤ 5 mg PSL per day is identically low (i.e., just as good QOL) as that seen in CSR and is a target of treatment. In order to veer away from high-dose oral corticosteroids and to achieve early MM or better status with PSL ≤ 5 mg/day, we advocate the early aggressive treatment strategy that can achieve early improvement by performing an aggressive therapy using combined treatment with plasmapheresis and high-dose intravenous methylprednisolone and then maintain an improved clinical status using low-dose oral corticosteroids and calcineurin inhibitors (cyclosporine microemulsion and tacrolimus). The early stages of MG are susceptible to treatment with calcineurin inhibitors. When using cyclosporine microemulsion for MG, blood concentrations 2 h after administration (C2) correlate with clinical improvement and immediately before administration (C0) with side effects (increased serum creatinine and/or hypertension). Monitoring of C2 and C0 levels is useful to estimate efficacy and safety of the drug.

The calcineurin inhibitor tacrolimus reduces proteinuria in membranous nephropathy accompanied by a decrease in angiopoietin-like-4.

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Lei Peng

Full Text Available Tacrolimus is an anticalcineurinic agent with potent immunosuppressive activity that has recently been shown to have the added benefit of reducing proteinuria in membranous nephropathy (MN patients. However, its potential mechanisms remain unknown. To reveal the mechanism, rat cohorts were administered tacrolimus or vehicle from days 7 to 28 after the induction of passive Heymann nephritis (PHN. PHN induction resulted in heavy proteinuria and increased expression of desmin, a marker of injured podocytes. We also showed that the glomerular expression of angiopoietin-like-4 (Angptl4 was markedly upregulated in PHN rats and human MN followed by an increase in urine Angptl4 excretion. In addition, increased Angptl4 expression may be related to podocyte injury and proteinuria. Furthermore, upregulated Angptl4 expression primarily colocalized with podocytes rather than endothelial or mesangial cells, indicating that podocytes may be the source of Angptl4, which then gradually migrated to the glomerular basement membrane over time. However, tacrolimus treatment markedly reduced glomerular and urinary Angptl4, accompanied by a reduction in the established proteinuria and the promotion of podocyte repair. Additionally, glomerular immune deposits and circulating IgG levels induced by PHN clearly decreased following tacrolimus treatment. In conclusion, this is the first demonstration that the calcineurin inhibitor tacrolimus can reduce Angptl4 in podocytes accompanied by a decrease in established proteinuria and promotion of podocyte repair in MN.

Effect of conversion from calcineurin inhibitors to everolimus on hepatitis C viremia in adult kidney transplant recipients.

Science.gov (United States)

Pacheco, Larissa Sgaria; Garcia, Valter Duro; Prá, Ronivan Luis Dal; Cardoso, Bruna Doleys; Rodrigues, Mariana Ferras; Zanetti, Helen Kris; Meinerz, Gisele; Neumann, Jorge; Gnatta, Diego; Keitel, Elizete

2018-05-14

Currently, there is no specific immunosuppressive protocol for hepatitis C (HCV)-positive renal transplants recipients. Thus, the aim of this study was to evaluate the conversion effect to everolimus (EVR) on HCV in adult kidney recipients. This is an exploratory single-center, prospective, randomized, open label controlled trial with renal allograft recipients with HCV-positive serology. Participants were randomized for conversion to EVR or maintenance of calcineurin inhibitors. Thirty patients were randomized and 28 were followed-up for 12 months (conversion group, Group 1 =15 and control group, Group 2 =13). RT-PCR HCV levels reported in log values were comparable in both groups and among patients in the same group. The statistical analysis showed no interaction effect between time and group (p value G*M= 0.852), overtime intra-groups (p-value M=0.889) and between group (p-value G=0.286). Group 1 showed a higher incidence of dyslipidemia (p=0.03) and proteinuria events (p=0.01), while no difference was observed in the incidence of anemia (p=0.17), new onset of post-transplant diabetes mellitus (p=1.00) or urinary tract infection (p=0.60). The mean eGFR was similar in both groups. Our study did not show viral load decrease after conversion to EVR with maintenance of antiproliferative therapy.

Renal function, efficacy, and safety of sirolimus and mycophenolate mofetil after short-term calcineurin inhibitor-based quadruple therapy in de novo renal transplant patients: one-year analysis of a randomized multicenter trial.

Science.gov (United States)

Guba, Markus; Pratschke, Johann; Hugo, Christian; Krämer, Bernhard K; Nohr-Westphal, Constanze; Brockmann, Jens; Andrassy, Joachim; Reinke, Petra; Pressmar, Katharina; Hakenberg, Oliver; Fischereder, Michael; Pascher, Andreas; Illner, Wolf-Dieter; Banas, Bernhard; Jauch, Karl-Walter

2010-07-27

De novo sirolimus in calcineurin inhibitor-free regimens, although potentially useful to improve early renal function, are complicated by various drug-related side effects. We report a prospective open-label, multicenter, randomized trial to evaluate early conversion from a CsA-based to a sirolimus (SRL)-based regimen 10 to 24 days after renal transplantation. Of the 196 patients, 141 patients with a low-to-moderate immunological risk were eligible to be converted to SRL or to continue CsA. All patients received antithymocyte globulin-F single-bolus induction, mycophenolate mofetil, and steroids. The primary endpoint, renal function determined by S-creatinine and estimated glomerular filtration rate calculated by Nankivell formula at 12 months was significantly better in the SRL group (1.51+/-0.59 vs. 1.87+/-0.98 mg/dL or 64.5+/-25.2 vs. 53.4+/-18.0 mL/min/1.73 m). Patient survival, graft survival, and incidence of biopsy-proven acute rejection after conversion were not statistically different. Drug discontinuations were significantly higher in the SRL group (36.2% vs. 19.7%). Significantly, more patients in the SRL group reported acne, aphtous, and temporary hyperlipidemia, whereas cytomegalovirus viremia was significantly decreased (7.3% vs. 28.2%). Early conversion to a calcineurin inhibitor-free regimen with SRL in combination with mycophenolate mofetil may be a useful strategy to improve renal function. The identification of appropriate candidates and safe management of SRL-related adverse events will be a key to avoid the high rate of dropouts, which currently limit the broad applicability of this protocol.

The Functional Role of Calcineurin in Hypertrophy, Regeneration, and Disorders of Skeletal Muscle

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Kunihiro Sakuma

2010-01-01

Full Text Available Skeletal muscle uses calcium as a second messenger to respond and adapt to environmental stimuli. Elevations in intracellular calcium levels activate calcineurin, a serine/threonine phosphatase, resulting in the expression of a set of genes involved in the maintenance, growth, and remodeling of skeletal muscle. In this review, we discuss the effects of calcineurin activity on hypertrophy, regeneration, and disorders of skeletal muscle. Calcineurin is a potent regulator of muscle remodeling, enhancing the differentiation through upregulation of myogenin or MEF2A and downregulation of the Id1 family and myostatin. Foxo may also be a downstream candidate for a calcineurin signaling molecule during muscle regeneration. The strategy of controlling the amount of calcineurin may be effective for the treatment of muscular disorders such as DMD, UCMD, and LGMD. Activation of calcineurin produces muscular hypertrophy of the slow-twitch soleus muscle but not fast-twitch muscles.

PKC signaling regulates drug resistance of the fungal pathogen Candida albicans via circuitry comprised of Mkc1, calcineurin, and Hsp90.

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Shantelle L LaFayette

2010-08-01

Full Text Available Fungal pathogens exploit diverse mechanisms to survive exposure to antifungal drugs. This poses concern given the limited number of clinically useful antifungals and the growing population of immunocompromised individuals vulnerable to life-threatening fungal infection. To identify molecules that abrogate resistance to the most widely deployed class of antifungals, the azoles, we conducted a screen of 1,280 pharmacologically active compounds. Three out of seven hits that abolished azole resistance of a resistant mutant of the model yeast Saccharomyces cerevisiae and a clinical isolate of the leading human fungal pathogen Candida albicans were inhibitors of protein kinase C (PKC, which regulates cell wall integrity during growth, morphogenesis, and response to cell wall stress. Pharmacological or genetic impairment of Pkc1 conferred hypersensitivity to multiple drugs that target synthesis of the key cell membrane sterol ergosterol, including azoles, allylamines, and morpholines. Pkc1 enabled survival of cell membrane stress at least in part via the mitogen activated protein kinase (MAPK cascade in both species, though through distinct downstream effectors. Strikingly, inhibition of Pkc1 phenocopied inhibition of the molecular chaperone Hsp90 or its client protein calcineurin. PKC signaling was required for calcineurin activation in response to drug exposure in S. cerevisiae. In contrast, Pkc1 and calcineurin independently regulate drug resistance via a common target in C. albicans. We identified an additional level of regulatory control in the C. albicans circuitry linking PKC signaling, Hsp90, and calcineurin as genetic reduction of Hsp90 led to depletion of the terminal MAPK, Mkc1. Deletion of C. albicans PKC1 rendered fungistatic ergosterol biosynthesis inhibitors fungicidal and attenuated virulence in a murine model of systemic candidiasis. This work establishes a new role for PKC signaling in drug resistance, novel circuitry through which

Ocular Toxicity Profile of ST-162 and ST-168 as Novel Bifunctional MEK/PI3K Inhibitors.

Science.gov (United States)

Smith, Andrew; Pawar, Mercy; Van Dort, Marcian E; Galbán, Stefanie; Welton, Amanda R; Thurber, Greg M; Ross, Brian D; Besirli, Cagri G

2018-04-30

ST-162 and ST-168 are small-molecule bifunctional inhibitors of MEK and PI3K signaling pathways that are being developed as novel antitumor agents. Previous small-molecule and biologic MEK inhibitors demonstrated ocular toxicity events that were dose limiting in clinical studies. We evaluated in vitro and in vivo ocular toxicity profiles of ST-162 and ST-168. Photoreceptor cell line 661W and adult retinal pigment epithelium cell line ARPE-19 were treated with increasing concentrations of bifunctional inhibitors. Western blots, cell viability, and caspase activity assays were performed to evaluate MEK and PI3K inhibition and dose-dependent in vitro toxicity, and compared with monotherapy. In vivo toxicity profile was assessed by intravitreal injection of ST-162 and ST-168 in Dutch-Belted rabbits, followed by ocular examination and histological analysis of enucleated eyes. Retinal cell lines treated with ST-162 or ST-168 exhibited dose-dependent inhibition of MEK and PI3K signaling. Compared with inhibition by monotherapies and their combinations, bifunctional inhibitors demonstrated reduced cell death and caspase activity. In vivo, both bifunctional inhibitors exhibited a more favorable toxicity profile when compared with MEK inhibitor PD0325901. Novel MEK and PI3K bifunctional inhibitors ST-162 and ST-168 demonstrate favorable in vitro and in vivo ocular toxicity profiles, supporting their further development as potential therapeutic agents targeting multiple aggressive tumors.

Systemic and Nonrenal Adverse Effects Occurring in Renal Transplant Patients Treated with mTOR Inhibitors

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Gianluigi Zaza

2013-01-01

Full Text Available The mammalian target of rapamycin inhibitors (mTOR-I, sirolimus and everolimus, are immunosuppressive drugs largely used in renal transplantation. The main mechanism of action of these drugs is the inhibition of the mammalian target of rapamycin (mTOR, a regulatory protein kinase involved in lymphocyte proliferation. Additionally, the inhibition of the crosstalk among mTORC1, mTORC2, and PI3K confers the antineoplastic activities of these drugs. Because of their specific pharmacological characteristics and their relative lack of nephrotoxicity, these inhibitors are valid option to calcineurine inhibitors (CNIs for maintenance immunosuppression in renal transplant recipients with chronic allograft nephropathy. However, as other immunosuppressive drugs, mTOR-I may induce the development of several adverse effects that need to be early recognized and treated to avoid severe illness in renal transplant patients. In particular, mTOR-I may induce systemic nonnephrological side effects including pulmonary toxicity, hematological disorders, dysmetabolism, lymphedema, stomatitis, cutaneous adverse effects, and fertility/gonadic toxicity. Although most of the adverse effects are dose related, it is extremely important for clinicians to early recognize them in order to reduce dosage or discontinue mTOR-I treatment avoiding the onset and development of severe clinical complications.

Carbachol-mediated pigment granule dispersion in retinal pigment epithelium requires Ca2+ and calcineurin.

Science.gov (United States)

Johnson, Adam S; García, Dana M

2007-12-19

Inside bluegill (Lepomis macrochirus) retinal pigment epithelial cells, pigment granules move in response to extracellular signals. During the process of aggregation, pigment motility is directed toward the cell nucleus; in dispersion, pigment is directed away from the nucleus and into long apical processes. A number of different chemicals have been found to initiate dispersion, and carbachol (an acetylcholine analog) is one example. Previous research indicates that the carbachol-receptor interaction activates a Gq-mediated pathway which is commonly linked to Ca2+ mobilization. The purpose of the present study was to test for involvement of calcium and to probe calcium-dependent mediators to reveal their role in carbachol-mediated dispersion. Carbachol-induced pigment granule dispersion was blocked by the calcium chelator BAPTA. In contrast, the calcium channel antagonist verapamil, and incubation in Ca2+-free medium failed to block carbachol-induced dispersion. The calcineurin inhibitor cypermethrin blocked carbachol-induced dispersion; whereas, two protein kinase C inhibitors (staurosporine and bisindolylmaleimide II) failed to block carbachol-induced dispersion, and the protein kinase C activator phorbol 12-myristate 13-acetate failed to elicit dispersion. A rise in intracellular calcium is necessary for carbachol-induced dispersion; however, the Ca2+ requirement is not dependent on extracellular sources, implying that intracellular stores are sufficient to enable pigment granule dispersion to occur. Calcineurin is a likely Ca2+-dependent mediator involved in the signal cascade. Although the pathway leads to the generation of diacylglycerol and calcium (both required for the activation of certain PKC isoforms), our evidence does not support a significant role for PKC.

Cdk1, PKCδ and calcineurin-mediated Drp1 pathway contributes to mitochondrial fission-induced cardiomyocyte death

International Nuclear Information System (INIS)

Zaja, Ivan; Bai, Xiaowen; Liu, Yanan; Kikuchi, Chika; Dosenovic, Svjetlana; Yan, Yasheng; Canfield, Scott G.; Bosnjak, Zeljko J.

2014-01-01

Highlights: • Drp1-mediated increased mitochondrial fission but not fusion is involved the cardiomyocyte death during anoxia-reoxygenation injury. • Reactive oxygen species are upstream initiators of mitochondrial fission. • Increased mitochondrial fission is resulted from Cdk1-, PKCδ-, and calcineurin-mediated Drp1 pathways. - Abstract: Myocardial ischemia–reperfusion (I/R) injury is one of the leading causes of death and disability worldwide. Mitochondrial fission has been shown to be involved in cardiomyocyte death. However, molecular machinery involved in mitochondrial fission during I/R injury has not yet been completely understood. In this study we aimed to investigate molecular mechanisms of controlling activation of dynamin-related protein 1 (Drp1, a key protein in mitochondrial fission) during anoxia-reoxygenation (A/R) injury of HL1 cardiomyocytes. A/R injury induced cardiomyocyte death accompanied by the increases of mitochondrial fission, reactive oxygen species (ROS) production and activated Drp1 (pSer616 Drp1), and decrease of inactivated Drp1 (pSer637 Drp1) while mitochondrial fusion protein levels were not significantly changed. Blocking Drp1 activity with mitochondrial division inhibitor mdivi1 attenuated cell death, mitochondrial fission, and Drp1 activation after A/R. Trolox, a ROS scavenger, decreased pSer616 Drp1 level and mitochondrial fission after A/R. Immunoprecipitation assay further indicates that cyclin dependent kinase 1 (Cdk1) and protein kinase C isoform delta (PKCδ) bind Drp1, thus increasing mitochondrial fission. Inhibiting Cdk1 and PKCδ attenuated the increases in pSer616 Drp1, mitochondrial fission, and cardiomyocyte death. FK506, a calcineurin inhibitor, blocked the decrease in expression of inactivated pSer637 Drp1 and mitochondrial fission. Our findings reveal the following novel molecular mechanisms controlling mitochondrial fission during A/R injury of cardiomyocytes: (1) ROS are upstream initiators of

Cdk1, PKCδ and calcineurin-mediated Drp1 pathway contributes to mitochondrial fission-induced cardiomyocyte death

Energy Technology Data Exchange (ETDEWEB)

Zaja, Ivan [Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226 (United States); Bai, Xiaowen, E-mail: xibai@mcw.edu [Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226 (United States); Liu, Yanan; Kikuchi, Chika; Dosenovic, Svjetlana; Yan, Yasheng; Canfield, Scott G. [Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226 (United States); Bosnjak, Zeljko J. [Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226 (United States); Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226 (United States)

2014-10-31

Highlights: • Drp1-mediated increased mitochondrial fission but not fusion is involved the cardiomyocyte death during anoxia-reoxygenation injury. • Reactive oxygen species are upstream initiators of mitochondrial fission. • Increased mitochondrial fission is resulted from Cdk1-, PKCδ-, and calcineurin-mediated Drp1 pathways. - Abstract: Myocardial ischemia–reperfusion (I/R) injury is one of the leading causes of death and disability worldwide. Mitochondrial fission has been shown to be involved in cardiomyocyte death. However, molecular machinery involved in mitochondrial fission during I/R injury has not yet been completely understood. In this study we aimed to investigate molecular mechanisms of controlling activation of dynamin-related protein 1 (Drp1, a key protein in mitochondrial fission) during anoxia-reoxygenation (A/R) injury of HL1 cardiomyocytes. A/R injury induced cardiomyocyte death accompanied by the increases of mitochondrial fission, reactive oxygen species (ROS) production and activated Drp1 (pSer616 Drp1), and decrease of inactivated Drp1 (pSer637 Drp1) while mitochondrial fusion protein levels were not significantly changed. Blocking Drp1 activity with mitochondrial division inhibitor mdivi1 attenuated cell death, mitochondrial fission, and Drp1 activation after A/R. Trolox, a ROS scavenger, decreased pSer616 Drp1 level and mitochondrial fission after A/R. Immunoprecipitation assay further indicates that cyclin dependent kinase 1 (Cdk1) and protein kinase C isoform delta (PKCδ) bind Drp1, thus increasing mitochondrial fission. Inhibiting Cdk1 and PKCδ attenuated the increases in pSer616 Drp1, mitochondrial fission, and cardiomyocyte death. FK506, a calcineurin inhibitor, blocked the decrease in expression of inactivated pSer637 Drp1 and mitochondrial fission. Our findings reveal the following novel molecular mechanisms controlling mitochondrial fission during A/R injury of cardiomyocytes: (1) ROS are upstream initiators of

Thrombotic microangiopathy associated with Valproic acid toxicity.

Science.gov (United States)

Hebert, Sean A; Bohan, Timothy P; Erikson, Christian L; Swinford, Rita D

2017-08-03

Thrombotic microangiopathy (TMA) is a serious, sometimes life-threatening disorder marked by the presence of endothelial injury and microvascular thrombi. Drug-induced thrombotic microangiopathy (DI-TMA) is one specific TMA syndrome that occurs following drug exposure via drug-dependent antibodies or direct tissue toxicity. Common examples include calcineurin inhibitors Tacrolimus and Cyclosporine and antineoplastics Gemcitabine and Mitomycin. Valproic acid has not been implicated in DI-TMA. We present the first case of a patient meeting clinical criteria for DI-TMA following admission for valproic acid toxicity. An adolescent male with difficult to control epilepsy was admitted for impaired hepatic function while on valproic acid therapy. On the third hospital day, he developed severe metabolic lactic acidosis and multiorgan failure, prompting transfer to the pediatric intensive care unit. Progressive anemia and thrombocytopenia instigated an evaluation for thrombotic microangiopathy, where confirmed by concomitant hemolysis, elevated lactate dehydrogenase (LDH), low haptoglobin, and concurrent oliguric acute kidney injury. Thrombotic thrombocytopenic purpura was less likely with adequate ADAMTS13. Discontinuing valproic acid reversed the anemia, thrombocytopenia, and normalized the LDH and haptoglobin, supporting a drug-induced cause for the TMA. To the best of our knowledge, this is the first report of drug-induced TMA from valproic acid toxicity.

Mixture and single-substance toxicity of selective serotonin reuptake inhibitors toward algae and crustaceans

DEFF Research Database (Denmark)

Christensen, Anne Munch; Faaborg-Andersen, S.; Ingerslev, Flemming

2007-01-01

Selective serotonin reuptake inhibitors (SSRIs) are used as antidepressant medications. primarily in the treatment of clinical depression. They are among the pharmaceuticals most often Prescribed in the industrialized countries. Selective serotonin reuptake inhibitors are compounds with an identi......Selective serotonin reuptake inhibitors (SSRIs) are used as antidepressant medications. primarily in the treatment of clinical depression. They are among the pharmaceuticals most often Prescribed in the industrialized countries. Selective serotonin reuptake inhibitors are compounds...... with an identical mechanism of action in mammals (inhibit reuptake of serotonin), and they have been found in different aqeous as well as biological samples collected in the environment. In the present study, we tested the toxicities of five SSRIs (citalopram, fluoxetine, fluoxamine, paroxetine, and sertraline.......027 to 1.6 mg/L, and in daphnids, test EC50s ranged from 0.92 to 20 mg/L, with sertraline being one of the most toxic compounds. The test design and statistical analysis of results from mixture tests were based on isobole analysis. It was demonstrated that the mixture toxicity of the SSRIs in the two...

Cyclosporine toxicity in immunosuppressed streptozotocin-diabetic nonhuman primates

International Nuclear Information System (INIS)

Wijkstrom, Martin; Kirchhof, Nicole; Graham, Melanie; Ingulli, Elizabeth; Colvin, Robert B.; Christians, Uwe; Hering, Bernhard J.; Schuurman, Henk-Jan

2005-01-01

Streptozotocin (STZ) is widely applied in animal models of insulin-dependent diabetes mellitus. Adverse effects of STZ mainly concern liver and kidney. In nonhuman primates a single 100-150 mg/kg dose invariably induces diabetes with only rare adverse effects. We report one animal with renal failure necessitating sacrifice. Body weight (age) might be a confounding factor, i.e. older animals might be more vulnerable to STZ-related toxicity. We therefore recommended to administer STZ on a mg/m 2 basis and not on a mg/kg basis. In our islet transplantation program nonhuman primates with STZ-induced diabetes received transplants under chronic immunosuppression including calcineurin inhibitors (cyclosporine, tacrolimus), drugs in the rapamycin class affecting growth factor-induced cell proliferation, and the sphingosine 1-phosphate receptor antagonist FTY720. Four animals developed renal failure and had to be sacrificed, most likely caused by cyclosporine. Kidney histology was typical for cyclosporine toxicity including thrombotic microangiopathy in glomeruli and fibrinoid necrosis of arteries, and for STZ toxicity including acute tubular necrosis and accumulations of erythroid precursors. This adverse effect was observed at a pharmacologically active cyclosporine exposure. Additionally, six diabetic animals without major adverse effects during cyclosporine or tacrolimus treatment are presented. We conclude that cyclosporine facilitates renal dysfunction in animals with STZ-induced diabetes, presumably related to an increased vulnerability to a toxic insult after STZ administration

Carbachol-mediated pigment granule dispersion in retinal pigment epithelium requires Ca2+ and calcineurin

Directory of Open Access Journals (Sweden)

García Dana M

2007-12-01

Full Text Available Abstract Background Inside bluegill (Lepomis macrochirus retinal pigment epithelial cells, pigment granules move in response to extracellular signals. During the process of aggregation, pigment motility is directed toward the cell nucleus; in dispersion, pigment is directed away from the nucleus and into long apical processes. A number of different chemicals have been found to initiate dispersion, and carbachol (an acetylcholine analog is one example. Previous research indicates that the carbachol-receptor interaction activates a Gq-mediated pathway which is commonly linked to Ca2+ mobilization. The purpose of the present study was to test for involvement of calcium and to probe calcium-dependent mediators to reveal their role in carbachol-mediated dispersion. Results Carbachol-induced pigment granule dispersion was blocked by the calcium chelator BAPTA. In contrast, the calcium channel antagonist verapamil, and incubation in Ca2+-free medium failed to block carbachol-induced dispersion. The calcineurin inhibitor cypermethrin blocked carbachol-induced dispersion; whereas, two protein kinase C inhibitors (staurosporine and bisindolylmaleimide II failed to block carbachol-induced dispersion, and the protein kinase C activator phorbol 12-myristate 13-acetate failed to elicit dispersion. Conclusion A rise in intracellular calcium is necessary for carbachol-induced dispersion; however, the Ca2+ requirement is not dependent on extracellular sources, implying that intracellular stores are sufficient to enable pigment granule dispersion to occur. Calcineurin is a likely Ca2+-dependent mediator involved in the signal cascade. Although the pathway leads to the generation of diacylglycerol and calcium (both required for the activation of certain PKC isoforms, our evidence does not support a significant role for PKC.

Correlations between calcineurin phosphatase inhibition and cyclosporine metabolites concentrations in kidney transplant recipients: Implications for immunoassays

DEFF Research Database (Denmark)

Jørgensen, Kaj Anker; Karamperis, Nikolaos; Koefoed-Nielsen, Pernille Bundgaard

2006-01-01

by inhibiting the enzyme calcineurin phosphatase. Determination of the enzyme's activity is one of the most promising pharmacodynamic markers. It is unknown how calcineurin phosphatase inhibition correlates with various cyclosporine monitoring assays and what is the potential impact of metabolites...... by the enzyme multiplied immunoassay technique (EMIT) and by the polyclonal fluorescence polarization immunoassay (pFPIA). Calcineurin phosphatase activity was measured by its ability to dephosphorylate a previously phosphorylated 19-amino acid peptide. We found that calcineurin phosphatase inhibition...

Correlations between calcineurin phosphatase inhibition and cyclosporine metabolites concentrations in kidney transplant recipients: implications for immunoassays

DEFF Research Database (Denmark)

Karamperis, N; Koefoed-Nielsen, PB; Brahe, P

2006-01-01

by inhibiting the enzyme calcineurin phosphatase. Determination of the enzyme's activity is one of the most promising pharmacodynamic markers. It is unknown how calcineurin phosphatase inhibition correlates with various cyclosporine monitoring assays and what is the potential impact of metabolites...... by the enzyme multiplied immunoassay technique (EMIT) and by the polyclonal fluorescence polarization immunoassay (pFPIA). Calcineurin phosphatase activity was measured by its ability to dephosphorylate a previously phosphorylated 19-amino acid peptide. We found that calcineurin phosphatase inhibition...

Estradiol upregulates calcineurin expression via overexpression of estrogen receptor alpha gene in systemic lupus erythematosus

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Hui-Li Lin

2011-04-01

Full Text Available Systemic lupus erythematosus (SLE is an autoimmune disease primarily affecting women (9:1 compared with men. To investigate the influence of female sex hormone estrogen on the development of female-biased lupus, we compared the expression of estrogen receptor alpha (ERα gene and protein levels as well as expression of T-cell activation gene calcineurin in response to estrogen in peripheral blood lymphocytes (PBLs from SLE patients and normal controls. PBLs were isolated from 20 female SLE patients and 6 normal female controls. The amount of ERα protein in PBL was measured by flow cytometry. The expression of ERα and calcineurin messenger RNA was measured by semi-quantitative reverse transcription-polymerase chain reaction. Calcineurin phosphatase activity was measured by calcineurin assay kit. The expression of ERα messenger RNA and ERα protein was significantly increased (p=0.001 and p=0.023, respectively in PBL from SLE patients compared with that from normal controls. In addition, the basal calcineurin in PBL from SLE patients was significantly higher (p=0.000 than that from normal controls, and estrogen-induced expression of calcineurin was increased (p=0.007 in PBL from SLE patients compared with that from normal controls, a 3.15-fold increase. This increase was inhibited by the ERα antagonism ICI 182,780. The effects of ER antagonism were also found in calcineurin activity. These data suggest that overexpression of ERα gene and enhanced activation of calcineurin in response to estrogen in PBL may contribute to the pathogenesis of female dominant in SLE.

Role of calmodulin and calcineurin in regulating flagellar motility and wave polarity in Leishmania.

Science.gov (United States)

Mukhopadhyay, Aakash Gautam; Dey, Chinmoy Sankar

2017-11-01

We have previously reported the involvement of cyclic AMP in regulating flagellar waveforms in Leishmania. Here, we investigated the roles of calcium, calmodulin, and calcineurin in flagellar motility regulation in L. donovani. Using high-speed videomicroscopy, we show that calcium-independent calmodulin and calcineurin activity is necessary for motility in Leishmania. Inhibition of calmodulin and calcineurin induced ciliary beats interrupting flagellar beating in both live (in vivo) and ATP-reactivated (in vitro) parasites. Our results indicate that signaling mediated by calmodulin and calcineurin operates antagonistically to cAMP signaling in regulating the waveforms of Leishmania flagellum. These two pathways are possibly involved in maintaining the balance between the two waveforms, essential for responding to environmental cues, survival, and infectivity.

Early conversion to a sirolimus-based, calcineurin-inhibitor-free immunosuppression in the SMART trial: observational results at 24 and 36months after transplantation.

Science.gov (United States)

Guba, Markus; Pratschke, Johann; Hugo, Christian; Krämer, Bernhard K; Pascher, Andreas; Pressmar, Katharina; Hakenberg, Oliver; Fischereder, Michael; Brockmann, Jens; Andrassy, Joachim; Banas, Bernhard; Jauch, Karl-Walter

2012-04-01

Early conversion to a calcineurin-inhibitor (CNI)-free maintenance immunosuppression with sirolimus (SRL), mycophenolate mofetil (MMF) and steroids was associated with an improved 1-year renal function as compared with a cyclosporine (CsA)-based regimen (SMART core-study). This observational follow-up describes 132 patients followed up within the SMART study framework for 36months. At 36months, renal function continued to be superior in SRL-treated patients [ITT-eGFR(@36m) : 60.88 vs. 53.72 (CsA) ml/min/1.73m(2) , P=0.031]. However, significantly more patients discontinued therapy in the SRL group 59.4% vs.42.3% (CsA). Patient [99% (SRL) vs.97% (CsA) and graft 96% (SRL) vs.94% (CsA)] survival at 36months was excellent in both arms. There was no difference in late rejection episodes. Late infections and adverse events were similar in both arms except of a higher rate of hyperlipidemia in SRL and a higher incidence of malignancy in CsA-treated patients. In a multivariate analysis, donor age >60years, S-creatinine at conversion >2mg/dl, CMV naïve(-) recipients and immunosuppression with CsA were predictive of an impaired renal function at 36months. Early conversion to a CNI-free SRL-based immunosuppression is associated with a sustained improvement of renal function up to 36months after transplantation. Patient selection will be key to derive long-term benefit and avoid treatment failure using this mTOR-inhibitor-based immunosuppressive regimen. © 2012 The Authors. Transplant International © 2012 European Society for Organ Transplantation.

Calcineurin orchestrates dimorphic transitions, antifungal drug responses and host-pathogen interactions of the pathogenic mucoralean fungus Mucor circinelloides.

Science.gov (United States)

Lee, Soo Chan; Li, Alicia; Calo, Silvia; Inoue, Makoto; Tonthat, Nam K; Bain, Judith M; Louw, Johanna; Shinohara, Mari L; Erwig, Lars P; Schumacher, Maria A; Ko, Dennis C; Heitman, Joseph

2015-09-01

Calcineurin plays essential roles in virulence and growth of pathogenic fungi and is a target of the natural products FK506 and Cyclosporine A. In the pathogenic mucoralean fungus Mucor circinelloides, calcineurin mutation or inhibition confers a yeast-locked phenotype indicating that calcineurin governs the dimorphic transition. Genetic analysis in this study reveals that two calcineurin A catalytic subunits (out of three) are functionally diverged. Homology modeling illustrates modes of resistance resulting from amino substitutions in the interface between each calcineurin subunit and the inhibitory drugs. In addition, we show how the dimorphic transition orchestrated by calcineurin programs different outcomes during host-pathogen interactions. For example, when macrophages phagocytose Mucor yeast, subsequent phagosomal maturation occurs, indicating host cells respond appropriately to control the pathogen. On the other hand, upon phagocytosis of spores, macrophages fail to form mature phagosomes. Cytokine production from immune cells differs following exposure to yeast versus spores (which germinate into hyphae). Thus, the morphogenic transition can be targeted as an efficient treatment option against Mucor infection. In addition, genetic analysis (including gene disruption and mutational studies) further strengthens the understanding of calcineurin and provides a foundation to develop antifungal agents targeting calcineurin to deploy against Mucor and other pathogenic fungi. © 2015 John Wiley & Sons Ltd.

Arctigenin inhibits osteoclast differentiation and function by suppressing both calcineurin-dependent and osteoblastic cell-dependent NFATc1 pathways.

Science.gov (United States)

Yamashita, Teruhito; Uehara, Shunsuke; Udagawa, Nobuyuki; Li, Feng; Kadota, Shigetoshi; Esumi, Hiroyasu; Kobayashi, Yasuhiro; Takahashi, Naoyuki

2014-01-01

Arctigenin, a lignan-derived compound, is a constituent of the seeds of Arctium lappa. Arctigenin was previously shown to inhibit osteoclastogenesis; however, this inhibitory mechanism has yet to be elucidated. Here, we showed that arctigenin inhibited the action of nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), a key transcription factor for osteoclastogenesis. NFATc1 in osteoclast precursors was activated through two distinct pathways: the calcineurin-dependent and osteoblastic cell-dependent pathways. Among the several lignan-derived compounds examined, arctigenin most strongly inhibited receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclast-like cell formation in mouse bone marrow macrophage (BMM) cultures, in which the calcineurin-dependent NFATc1 pathway was activated. Arctigenin suppressed neither the activation of nuclear factor κB and mitogen-activated protein kinases nor the up-regulation of c-Fos expression in BMMs treated with RANKL. However, arctigenin suppressed RANKL-induced NFATc1 expression. Interestingly, the treatment of osteoclast-like cells with arctigenin converted NFATc1 into a lower molecular weight species, which was translocated into the nucleus even in the absence of RANKL. Nevertheless, arctigenin as well as cyclosporin A (CsA), a calcineurin inhibitor, suppressed the NFAT-luciferase reporter activity induced by ionomycin and phorbol 12-myristate 13-acetate in BMMs. Chromatin immunoprecipitation analysis confirmed that arctigenin inhibited the recruitment of NFATc1 to the promoter region of the NFATc1 target gene. Arctigenin, but not CsA suppressed osteoclast-like cell formation in co-cultures of osteoblastic cells and bone marrow cells, in which the osteoblastic cell-dependent NFATc1 pathway was activated. The forced expression of constitutively active NFATc1 rescued osteoclastogenesis in BMM cultures treated with CsA, but not that treated with arctigenin. Arctigenin also suppressed the pit

Arctigenin Inhibits Osteoclast Differentiation and Function by Suppressing Both Calcineurin-Dependent and Osteoblastic Cell-Dependent NFATc1 Pathways

Science.gov (United States)

Yamashita, Teruhito; Uehara, Shunsuke; Udagawa, Nobuyuki; Li, Feng; Kadota, Shigetoshi; Esumi, Hiroyasu; Kobayashi, Yasuhiro; Takahashi, Naoyuki

2014-01-01

Arctigenin, a lignan-derived compound, is a constituent of the seeds of Arctium lappa. Arctigenin was previously shown to inhibit osteoclastogenesis; however, this inhibitory mechanism has yet to be elucidated. Here, we showed that arctigenin inhibited the action of nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), a key transcription factor for osteoclastogenesis. NFATc1 in osteoclast precursors was activated through two distinct pathways: the calcineurin-dependent and osteoblastic cell-dependent pathways. Among the several lignan-derived compounds examined, arctigenin most strongly inhibited receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclast-like cell formation in mouse bone marrow macrophage (BMM) cultures, in which the calcineurin-dependent NFATc1 pathway was activated. Arctigenin suppressed neither the activation of nuclear factor κB and mitogen-activated protein kinases nor the up-regulation of c-Fos expression in BMMs treated with RANKL. However, arctigenin suppressed RANKL-induced NFATc1 expression. Interestingly, the treatment of osteoclast-like cells with arctigenin converted NFATc1 into a lower molecular weight species, which was translocated into the nucleus even in the absence of RANKL. Nevertheless, arctigenin as well as cyclosporin A (CsA), a calcineurin inhibitor, suppressed the NFAT-luciferase reporter activity induced by ionomycin and phorbol 12-myristate 13-acetate in BMMs. Chromatin immunoprecipitation analysis confirmed that arctigenin inhibited the recruitment of NFATc1 to the promoter region of the NFATc1 target gene. Arctigenin, but not CsA suppressed osteoclast-like cell formation in co-cultures of osteoblastic cells and bone marrow cells, in which the osteoblastic cell-dependent NFATc1 pathway was activated. The forced expression of constitutively active NFATc1 rescued osteoclastogenesis in BMM cultures treated with CsA, but not that treated with arctigenin. Arctigenin also suppressed the pit

Arctigenin inhibits osteoclast differentiation and function by suppressing both calcineurin-dependent and osteoblastic cell-dependent NFATc1 pathways.

Directory of Open Access Journals (Sweden)

Teruhito Yamashita

Full Text Available Arctigenin, a lignan-derived compound, is a constituent of the seeds of Arctium lappa. Arctigenin was previously shown to inhibit osteoclastogenesis; however, this inhibitory mechanism has yet to be elucidated. Here, we showed that arctigenin inhibited the action of nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1, a key transcription factor for osteoclastogenesis. NFATc1 in osteoclast precursors was activated through two distinct pathways: the calcineurin-dependent and osteoblastic cell-dependent pathways. Among the several lignan-derived compounds examined, arctigenin most strongly inhibited receptor activator of nuclear factor κB ligand (RANKL-induced osteoclast-like cell formation in mouse bone marrow macrophage (BMM cultures, in which the calcineurin-dependent NFATc1 pathway was activated. Arctigenin suppressed neither the activation of nuclear factor κB and mitogen-activated protein kinases nor the up-regulation of c-Fos expression in BMMs treated with RANKL. However, arctigenin suppressed RANKL-induced NFATc1 expression. Interestingly, the treatment of osteoclast-like cells with arctigenin converted NFATc1 into a lower molecular weight species, which was translocated into the nucleus even in the absence of RANKL. Nevertheless, arctigenin as well as cyclosporin A (CsA, a calcineurin inhibitor, suppressed the NFAT-luciferase reporter activity induced by ionomycin and phorbol 12-myristate 13-acetate in BMMs. Chromatin immunoprecipitation analysis confirmed that arctigenin inhibited the recruitment of NFATc1 to the promoter region of the NFATc1 target gene. Arctigenin, but not CsA suppressed osteoclast-like cell formation in co-cultures of osteoblastic cells and bone marrow cells, in which the osteoblastic cell-dependent NFATc1 pathway was activated. The forced expression of constitutively active NFATc1 rescued osteoclastogenesis in BMM cultures treated with CsA, but not that treated with arctigenin. Arctigenin also suppressed the

Toxicity management of angiogenesis inhibitors: resolution of expert panel

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Pavel O. Rumiantsev

2017-12-01

Full Text Available On 22 June 2017 in St. Petersburg the expert panel was held on the topic “Management of toxicity of angiogenesis inhibitors”, which discussed current issues of systemic therapy of advanced differentiated thyroid cancer resistant to radioactive iodine therapy, advanced kidney cancer and questions of efficacy and safety of new target drugs in the treatment of these diseases. The reports and discussions of experts raised the following questions: 1. Own experience of using lenvatinib in patients with differentiated thyroid cancer refractory to therapy with radioactive iodine and kidney cancer. 2. Profile of efficacy and safety of modern targeted therapy with multikinase inhibitors. 3. Prophylaxis and management of predictable toxicity.

Transgenic overexpression of active calcineurin in beta-cells results in decreased beta-cell mass and hyperglycemia.

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Ernesto Bernal-Mizrachi

2010-08-01

Full Text Available Glucose modulates beta-cell mass and function through an initial depolarization and Ca(2+ influx, which then triggers a number of growth regulating signaling pathways. One of the most important downstream effectors in Ca(2+ signaling is the calcium/Calmodulin activated serine threonine phosphatase, calcineurin. Recent evidence suggests that calcineurin/NFAT is essential for beta-cell proliferation, and that in its absence loss of beta-cells results in diabetes. We hypothesized that in contrast, activation of calcineurin might result in expansion of beta-cell mass and resistance to diabetes.To determine the role of activation of calcineurin signaling in the regulation of pancreatic beta-cell mass and proliferation, we created mice that expressed a constitutively active form of calcineurin under the insulin gene promoter (caCn(RIP. To our surprise, these mice exhibited glucose intolerance. In vitro studies demonstrated that while the second phase of Insulin secretion is enhanced, the overall insulin secretory response was conserved. Islet morphometric studies demonstrated decreased beta-cell mass suggesting that this was a major component responsible for altered Insulin secretion and glucose intolerance in caCn(RIP mice. The reduced beta-cell mass was accompanied by decreased proliferation and enhanced apoptosis.Our studies identify calcineurin as an important factor in controlling glucose homeostasis and indicate that chronic depolarization leading to increased calcineurin activity may contribute, along with other genetic and environmental factors, to beta-cell dysfunction and diabetes.

Shikonin, a constituent of Lithospermum erythrorhizon exhibits anti-allergic effects by suppressing orphan nuclear receptor Nr4a family gene expression as a new prototype of calcineurin inhibitors in mast cells.

Science.gov (United States)

Wang, Xiaoyu; Hayashi, Shusaku; Umezaki, Masahito; Yamamoto, Takeshi; Kageyama-Yahara, Natsuko; Kondo, Takashi; Kadowaki, Makoto

2014-12-05

inhibition of calcineurin activity. Therefore, shikonin has therapeutic potential for the treatment of allergic diseases as a new calcineurin inhibitor. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Kaempferol Promotes Transplant Tolerance by Sustaining CD4+FoxP3+ Regulatory T Cells in the Presence of Calcineurin Inhibitor.

Science.gov (United States)

Zeng, Y Q; Liu, X S; Wu, S; Zou, C; Xie, Q; Xu, S M; Jin, X W; Li, W; Zhou, A; Dai, Z

2015-07-01

Calcineurin inhibitor cyclosporine is widely used as an immunosuppressant in clinic. However, mounting evidence has shown that cyclosporine hinders tolerance induction by dampening Tregs. Therefore, it is of paramount importance to overcome this pitfall. Kaempferol was reported to inhibit DC function. Here, we found that kaempferol delayed islet allograft rejection. Combination of kaempferol and low-dose, but not high-dose, of cyclosporine induced allograft tolerance in majority of recipient mice. Although kaempferol plus either dose of cyclosporine largely abrogated proliferation of graft-infiltrating T cells and their CTL activity, both proliferation and CTL activity in mice treated with kaempferol plus low-dose, but not high-dose, cyclosporine reemerged rapidly upon treatment withdrawal. Kaempferol increased CD4+FoxP3+ Tregs both in transplanted mice and in vitro, likely by suppressing DC maturation and their IL-6 expression. Reduction in Tregs by low dose of cyclosporine was reversed by kaempferol. Kaempferol-induced Tregs exhibited both allospecific and non-allospecific suppression. Administering IL-6 abrogated allograft tolerance induced by kaempferol and cyclosporine via diminishing CD4+FoxP3+ Tregs. Thus, for the first time, we demonstrated that kaempferol promotes transplant tolerance in the presence of low dose of cyclosporine, which allows for sufficient Treg generation while minimizing side effects, resulting in much-needed synergy between kaempferol and cyclosporine. © Copyright 2015 The American Society of Transplantation and the American Society of Transplant Surgeons.

Angiotensin II induces calcium/calcineurin signaling and podocyte injury by downregulating microRNA-30 family members.

Science.gov (United States)

Zhao, Yue; Wu, Junnan; Zhang, Mingchao; Zhou, Minlin; Xu, Feng; Zhu, Xiaodong; Zhou, Xianguang; Lang, Yue; Yang, Fan; Yun, Shifeng; Shi, Shaolin; Liu, Zhihong

2017-08-01

Angiotensin II (AngII) is capable of inducing calcium/calcineurin signaling and podocyte injury; however, the precise underlying mechanism is not well understood. Because we have previously demonstrated that microRNA-30s (miR-30s) inhibit calcium/calcineurin signaling in podocytes, we hypothesize that AngII may induce podocyte injury by downregulating miR-30s and thereby activating calcium/calcineurin signaling. To test this hypothesis, we used an AngII-induced podocyte injury mouse model. The mice were treated with AngII via infusion for 28 days, which resulted in hypertension, albuminuria, and glomerular damage. AngII treatment also resulted in a significant reduction of miR-30s and upregulation of calcium/calcineurin signaling components, including TRPC6, PPP3CA, PPP3CB, PPP3R1, and NFATC3, which are the known targets of miR-30s in podocytes. The delivery of miR-30a-expressing lentivirus to the podocytes on day 14 of the infusion ameliorated the AngII-induced podocyte and glomerular injury and attenuated the upregulation of the calcium/calcineurin signaling components. Similarly, treatment with losartan, which is an AngII receptor blocker, also prevented AngII-induced podocyte injury and calcium/calcineurin signaling activation. Notably, losartan was found to sustain miR-30 levels during AngII treatment both in vivo and in vitro. In conclusion, the effect of AngII on podocytes is in part mediated by miR-30s through calcium/calcineurin signaling, a novel mechanism underlying AngII-induced podocyte injury. • AngII infusion resulted in downregulation of miR-30s in podocytes. • Exogenous miR-30a delivery mitigated the glomerular and podocyte injuries induced by AngII. • Both miR-30a and losartan prevented AngII-induced activation of calcium-calcineurin signaling.

Toxicity of Nitrification Inhibitors on Dehydrogenase Activity in Soils

OpenAIRE

Ferisman Tindaon; Gero Benckiser; Johannes C. G. Ottow

2011-01-01

The objective of this research was to determine the effects of nitrification inhibitors (NIs) such as 3,4-dimethylpyrazolephosphate=DMPP, 4-Chlor-methylpyrazole phosphate=ClMPP and dicyandiamide,DCD) which might be expected to inhibit microbial activity, on dehydrogenase activity (DRA),in three different soils in laboratory conditions. Dehydrogenase activity were assessed via reduction of 2-p-Iodophenyl-3-p-nitrophenyl-5-phenyltetrazoliumchloride (INT). The toxicity and dose response curve of...

Calcium Input Frequency, Duration and Amplitude Differentially Modulate the Relative Activation of Calcineurin and CaMKII

Science.gov (United States)

Li, Lu; Stefan, Melanie I.; Le Novère, Nicolas

2012-01-01

NMDA receptor dependent long-term potentiation (LTP) and long-term depression (LTD) are two prominent forms of synaptic plasticity, both of which are triggered by post-synaptic calcium elevation. To understand how calcium selectively stimulates two opposing processes, we developed a detailed computational model and performed simulations with different calcium input frequencies, amplitudes, and durations. We show that with a total amount of calcium ions kept constant, high frequencies of calcium pulses stimulate calmodulin more efficiently. Calcium input activates both calcineurin and Ca2+/calmodulin-dependent protein kinase II (CaMKII) at all frequencies, but increased frequencies shift the relative activation from calcineurin to CaMKII. Irrespective of amplitude and duration of the inputs, the total amount of calcium ions injected adjusts the sensitivity of the system to calcium input frequencies. At a given frequency, the quantity of CaMKII activated is proportional to the total amount of calcium. Thus, an input of a small amount of calcium at high frequencies can induce the same activation of CaMKII as a larger amount, at lower frequencies. Finally, the extent of activation of CaMKII signals with high calcium frequency is further controlled by other factors, including the availability of calmodulin, and by the potency of phosphatase inhibitors. PMID:22962589

Direct evidence that FK506 inhibition of FcepsilonRI-mediated exocytosis from RBL mast cells involves calcineurin.

Science.gov (United States)

Hultsch, T; Brand, P; Lohmann, S; Saloga, J; Kincaid, R L; Knop, J

1998-05-01

FcepsilonRI-mediated exocytosis of preformed mediators from mast cells and basophils (e.g. histamine, serotonin, beta-hexosaminidase) is sensitive to the immunosuppressants cyclosporin A and FK506 (IC50 200 and 4 nM, respectively) but not rapamycin. The mechanism of inhibition does not appear to involve tyrosine phosphorylation, hydrolysis of inositol phosphates or calcium flux. Here we report experiments using a molecular approach to assess the role of calcineurin, a serine/threonine phosphatase thought to be the primary pharmacological target of these drugs. Calcineurin's activity requires association of its catalytic (A) subunit with an intrinsic regulatory (B) subunit. We hypothesized that calcineurin-sensitive signalling events should be affected by the depletion of calcineurin B subunits, thereby reducing the number of active A:B complexes. We therefore transfected rat basophilic leukemia (RBL) cells with an inhibitory (dominant negative) form of the calcineurin A subunit, which binds the calcineurin B subunit with high affinity but does not possess catalytic activity (B subunit knock-out, BKO). In these transfected cells, the dose-response curve for the inhibition of FcepsilonRI-mediated exocytosis by FK506 was shifted to the left, indicating an increased drug sensitivity of BKO-transfected cells. We conclude that FK506 inhibition of FcepsilonRI-mediated exocytosis in mast cells specifically targets calcineurin activity.

PKA regulates calcineurin function through the phosphorylation of RCAN1: Identification of a novel phosphorylation site

International Nuclear Information System (INIS)

Kim, Seon Sook; Lee, Eun Hye; Lee, Kooyeon; Jo, Su-Hyun; Seo, Su Ryeon

2015-01-01

Calcineurin is a calcium/calmodulin-dependent phosphatase that has been implicated in T cell activation through the induction of nuclear factors of activated T cells (NFAT). We have previously suggested that endogenous regulator of calcineurin (RCAN1, also known as DSCR1) is targeted by protein kinase A (PKA) for the control of calcineurin activity. In the present study, we characterized the PKA-mediated phosphorylation site in RCAN1 by mass spectrometric analysis and revealed that PKA directly phosphorylated RCAN1 at the Ser 93. PKA-induced phosphorylation and the increase in the half-life of the RCAN1 protein were prevented by the substitution of Ser 93 with Ala (S93A). Furthermore, the PKA-mediated phosphorylation of RCAN1 at Ser 93 potentiated the inhibition of calcineurin-dependent pro-inflammatory cytokine gene expression by RCAN1. Our results suggest the presence of a novel phosphorylation site in RCAN1 and that its phosphorylation influences calcineurin-dependent inflammatory target gene expression. - Highlights: • We identify novel phosphorylation sites in RCAN1 by LC-MS/MS analysis. • PKA-dependent phosphorylation of RCAN1 at Ser 93 inhibits calcineurin-mediated intracellular signaling. • We show the immunosuppressive function of RCAN1 phosphorylation at Ser 93 in suppressing cytokine expression

Peptidomimetic hydroxamate metalloproteinase inhibitors abrogate local and systemic toxicity induced by Echis ocellatus (saw-scaled) snake venom.

Science.gov (United States)

Arias, Ana Silvia; Rucavado, Alexandra; Gutiérrez, José María

2017-06-15

The ability of two peptidomimetic hydroxamate metalloproteinase inhibitors, Batimastat and Marimastat, to abrogate toxic and proteinase activities of the venom of Echis ocellatus from Cameroon and Ghana was assessed. Since this venom largely relies for its toxicity on the action of zinc-dependent metalloproteinases (SVMPs), the hypothesis was raised that toxicity could be largely eliminated by using SVMP inhibitors. Both hydroxamate molecules inhibited local and pulmonary hemorrhagic, in vitro coagulant, defibrinogenating, and proteinase activities of the venoms in conditions in which venom and inhibitors were incubated prior to the test. In addition, the inhibitors prolonged the time of death of mice receiving 4 LD 50 s of venom by the intravenous route. Lower values of IC 50 were observed for in vitro and local hemorrhagic activities than for systemic effects. When experiments were performed in conditions that simulated the actual circumstances of snakebite, i.e. by administering the inhibitor after envenoming, Batimastat completely abrogated local hemorrhage if injected immediately after venom. Moreover, it was also effective at inhibiting lethality and defibrinogenation when venom and inhibitor were injected by the intraperitoneal route. Results suggest that these, and possibly other, metalloproteinase inhibitors may become an effective adjunct therapy in envenomings by E. ocellatus when administered at the anatomic site of venom injection rapidly after the bite. Copyright © 2017 Elsevier Ltd. All rights reserved.

A new calcineurin inhibition domain in Cabin1

International Nuclear Information System (INIS)

Jang, Hyonchol; Cho, Eun-Jung; Youn, Hong-Duk

2007-01-01

Calcineurin (CN), a calcium-activated phosphatase, plays a critical role in various biological processes including T cell activation. Cabin1, a calcineurin binding protein 1, has been shown to bind directly to CN using its C-terminal region and inhibit CN activity. However, no increase in CN activity has been found in Cabin1ΔC T cells, which produce a truncated Cabin1 lacking the C-terminal CN binding region. Here, we report that Cabin1 has additional CN binding domain in its 701-900 amino acid residues. Cabin1 (701-900) blocked both CN-mediated dephosphorylation and nuclear import of NFAT and thus inhibited IL-2 production in response to PMA/ionomycin stimulation. This fact may explain why Cabin1ΔC mice previously showed no significant defect in CN-mediated signaling pathway

Bio-testing integral toxicity of corrosion inhibitors, biocides and oil hydrocarbons in oil-and gas-processing industry

Energy Technology Data Exchange (ETDEWEB)

Chugunov, V.A.; Kholodenko, V.P.; Irkhina, I.A.; Fomchenkov, V.M.; Novikov, I.A. [State Research Center for Applied Microbiology, Obolensk, Moscow (Russian Federation)

2004-07-01

In recent years bioassays have been widely used for assessing levels of contamination of the environment. This is due to the fact that test-organisms provide a general response to toxicants present in samples. Based on microorganisms as test objects, it is possible to develop cheap, sensitive and rapid assays to identify environmental xenobiotics and toxicants. The objective of the research was to develop different microbiological assays for assessing integral toxicity of water environments polluted with corrosion inhibitors, biocides and hydrocarbons in oil- and gas-processing industry. Bio-luminescent, electro-orientational, osmo-optic and microorganism reducing activity assays were used for express evaluation of integral toxicity. They are found to determine promptly integral toxicity of water environments containing various pollutants (oil, oil products, corrosion inhibitors, biocides). Results conclude that the assays may be used for analyzing integral toxicity of water polluted with hydrocarbons, as well as for monitoring of water changes as a result of biodegradation of pollutants by microorganisms and their associations. Using a kit of different assays, it is also possible to evaluate ecological safety of biocides, corrosion inhibitors, and their compositions. Bioassays used as a kit are more effective than each assay individually, allowing one to get complete characterization of a reaction of bacterial test organisms to different environments. (authors)

Using high throughput experimental data and in silico models to discover alternatives to toxic chromate corrosion inhibitors

International Nuclear Information System (INIS)

Winkler, D.A.; Breedon, M.; White, P.; Hughes, A.E.; Sapper, E.D.; Cole, I.

2016-01-01

Highlights: • We screened a large library of organic compounds as replacements for toxic chromates. • High throughput automated corrosion testing was used to assess inhibitor performance. • Robust, predictive machine learning models of corrosion inhibition were developed. • Models indicated molecular features contributing to performance of organic inhibitors. • We also showed that quantum chemistry descriptors do not correlate with performance. - Abstract: Restrictions on the use of toxic chromate-based corrosion inhibitors have created important issues for the aerospace and other industries. Benign alternatives that offer similar or superior performance are needed. We used high throughput experiments to assess 100 small organic molecules as potential inhibitors of corrosion in aerospace aluminium alloys AA2024 and AA7075. We generated robust, predictive, quantitative computational models of inhibitor efficiency at two pH values using these data. The models identified molecular features of inhibitor molecules that had the greatest impact on corrosion inhibition. Models can be used to discover better corrosion inhibitors by screening libraries of organic compounds for candidates with high corrosion inhibition.

Bosutinib induced pleural effusions: Case report and review of tyrosine kinase inhibitors induced pulmonary toxicity

Directory of Open Access Journals (Sweden)

Natalia I. Moguillansky, MD

2017-01-01

Full Text Available Tyrosine kinase inhibitors are known to cause pulmonary complications. We report a case of bosutinib related bilateral pleural effusions in a patient with chronic myeloid leukemia. Characteristics of the pleural fluid are presented. We also discuss other tyrosine kinase inhibitors induced pulmonary toxicities, including pulmonary hypertension and interstitial lung disease.

Calcineurin signaling and membrane lipid homeostasis regulates iron mediated multidrug resistance mechanisms in Candida albicans.

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Saif Hameed

2011-04-01

Full Text Available We previously demonstrated that iron deprivation enhances drug susceptibility of Candida albicans by increasing membrane fluidity which correlated with the lower expression of ERG11 transcript and ergosterol levels. The iron restriction dependent membrane perturbations led to an increase in passive diffusion and drug susceptibility. The mechanisms underlying iron homeostasis and multidrug resistance (MDR, however, are not yet resolved. To evaluate the potential mechanisms, we used whole genome transcriptome and electrospray ionization tandem mass spectrometry (ESI-MS/MS based lipidome analyses of iron deprived Candida cells to examine the new cellular circuitry of the MDR of this pathogen. Our transcriptome data revealed a link between calcineurin signaling and iron homeostasis. Among the several categories of iron deprivation responsive genes, the down regulation of calcineurin signaling genes including HSP90, CMP1 and CRZ1 was noteworthy. Interestingly, iron deprived Candida cells as well as iron acquisition defective mutants phenocopied molecular chaperone HSP90 and calcineurin mutants and thus were sensitive to alkaline pH, salinity and membrane perturbations. In contrast, sensitivity to above stresses did not change in iron deprived DSY2146 strain with a hyperactive allele of calcineurin. Although, iron deprivation phenocopied compromised HSP90 and calcineurin, it was independent of protein kinase C signaling cascade. Notably, the phenotypes associated with iron deprivation in genetically impaired calcineurin and HSP90 could be reversed with iron supplementation. The observed down regulation of ergosterol (ERG1, ERG2, ERG11 and ERG25 and sphingolipid biosynthesis (AUR1 and SCS7 genes followed by lipidome analysis confirmed that iron deprivation not only disrupted ergosterol biosynthesis, but it also affected sphingolipid homeostasis in Candida cells. These lipid compositional changes suggested extensive remodeling of the membranes in iron

Molecular Cloning and Characterization of the Calcineurin Subunit A from Plutella xylostella

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Xi'en Chen

2013-10-01

Full Text Available Calcineurin (or PP2B has been reported to be involved in an array of physiological process in insects, and the calcineurin subunit A (CNA plays a central role in calcineurin activity. We cloned the CNA gene from Plutella xylostella (PxCNA. This gene contains an ORF of 1488 bp that encodes a 495 amino acid protein, showing 98%, and 80% identities to the CNA of Bombyx mori, and humans respectively. The full-length of PxCNA and its catalytic domain (CNA1–341, defined as PxCNα were both expressed in Escherichia coli. Purified recombinant PxCNA displayed no phosphatase activity, whereas recombinant PxCNα showed high phosphatase activity with a Km of 4.6 mM and a kcat of 0.66 S−1 against pNPP. It could be activated at different degrees by Mn2+, Ni2+, Mg2+, and Ca2+. The optimum reaction pH was about 7.5 and the optimum reaction temperature was around 45 °C. An in vitro inhibition assay showed that okadaic acid (OA and cantharidin (CTD competitively inhibited recombinant PxCNα activity with the IC50 values of 8.95 μM and 77.64 μM, respectively. However, unlike previous reports, pyrethroid insecticides were unable to inhibit recombinant PxCNα, indicating that the P. xylostella calcineurin appears not to be sensitive to class II pyrethroid insecticides.

Myeloid-Derived Suppressor Cells Ameliorate Cyclosporine A-Induced Hypertension in Mice.

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Chiasson, Valorie L; Bounds, Kelsey R; Chatterjee, Piyali; Manandhar, Lochana; Pakanati, Abhinandan R; Hernandez, Marcos; Aziz, Bilal; Mitchell, Brett M

2018-01-01

The calcineurin inhibitor cyclosporine A (CsA) suppresses the immune system but promotes hypertension, vascular dysfunction, and renal damage. CsA decreases regulatory T cells and this contributes to the development of hypertension. However, CsA's effects on another important regulatory immune cell subset, myeloid-derived suppressor cells (MDSCs), is unknown. We hypothesized that augmenting MDSCs would ameliorate the CsA-induced hypertension and vascular and renal injury and dysfunction and that CsA reduces MDSCs in mice. Daily interleukin-33 treatment, which increased MDSC levels, completely prevented CsA-induced hypertension and vascular and renal toxicity. Adoptive transfer of MDSCs from control mice into CsA-treated mice after hypertension was established dose-dependently reduced blood pressure and vascular and glomerular injury. CsA treatment of aortas and kidneys isolated from control mice for 24 hours decreased relaxation responses and increased inflammation, respectively, and these effects were prevented by the presence of MDSCs. MDSCs also prevented the CsA-induced increase in fibronectin in microvascular and glomerular endothelial cells. Last, CsA dose-dependently reduced the number of MDSCs by inhibiting calcineurin and preventing cell proliferation, as other direct calcineurin signaling pathway inhibitors had the same dose-dependent effect. These data suggest that augmenting MDSCs can reduce the cardiovascular and renal toxicity and hypertension caused by CsA. © 2017 American Heart Association, Inc.

Arsenic toxicity induced endothelial dysfunction and dementia: Pharmacological interdiction by histone deacetylase and inducible nitric oxide synthase inhibitors

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Sharma, Bhupesh, E-mail: drbhupeshresearch@gmail.com; Sharma, P.M.

2013-11-15

Arsenic toxicity has been reported to damage all the major organs including the brain and vasculature. Dementia including Alzheimer's disease (AD) and vascular dementia (VaD) are posing greater risk to the world population as it is now increasing at a faster rate. We have investigated the role of sodium butyrate, a selective histone deacetylase (HDAC) inhibitor and aminoguanidine, a selective inducible nitric oxide synthase (iNOS) inhibitor in pharmacological interdiction of arsenic toxicity induced vascular endothelial dysfunction and dementia in rats. Arsenic toxicity was done by administering arsenic drinking water to rats. Morris water-maze (MWM) test was used for assessment of learning and memory. Endothelial function was assessed using student physiograph. Oxidative stress (aortic superoxide anion, serum and brain thiobarbituric acid reactive species, brain glutathione) and nitric oxide levels (serum nitrite/nitrate) were also measured. Arsenic treated rats have shown impairment of endothelial function, learning and memory, reduction in serum nitrite/nitrate and brain GSH levels along with increase in serum and brain TBARS. Sodium butyrate as well as aminoguanidine significantly convalesce arsenic induced impairment of learning, memory, endothelial function, and alterations in various biochemical parameters. It may be concluded that arsenic induces endothelial dysfunction and dementia, whereas, sodium butyrate, a HDAC inhibitor as well as aminoguanidine, a selective iNOS inhibitor may be considered as potential agents for the management of arsenic induced endothelial dysfunction and dementia. - Highlights: • As has induced endothelial dysfunction (Edf) and vascular dementia (VaD). • As has increased oxidative stress, AChE activity and decreased serum NO. • Inhibitors of HDAC and iNOS have attenuated As induced Edf and VaD. • Both the inhibitors have attenuated As induced biochemical changes. • Inhibitor of HDAC and iNOS has shown good potential

Arsenic toxicity induced endothelial dysfunction and dementia: Pharmacological interdiction by histone deacetylase and inducible nitric oxide synthase inhibitors

International Nuclear Information System (INIS)

Sharma, Bhupesh; Sharma, P.M.

2013-01-01

Arsenic toxicity has been reported to damage all the major organs including the brain and vasculature. Dementia including Alzheimer's disease (AD) and vascular dementia (VaD) are posing greater risk to the world population as it is now increasing at a faster rate. We have investigated the role of sodium butyrate, a selective histone deacetylase (HDAC) inhibitor and aminoguanidine, a selective inducible nitric oxide synthase (iNOS) inhibitor in pharmacological interdiction of arsenic toxicity induced vascular endothelial dysfunction and dementia in rats. Arsenic toxicity was done by administering arsenic drinking water to rats. Morris water-maze (MWM) test was used for assessment of learning and memory. Endothelial function was assessed using student physiograph. Oxidative stress (aortic superoxide anion, serum and brain thiobarbituric acid reactive species, brain glutathione) and nitric oxide levels (serum nitrite/nitrate) were also measured. Arsenic treated rats have shown impairment of endothelial function, learning and memory, reduction in serum nitrite/nitrate and brain GSH levels along with increase in serum and brain TBARS. Sodium butyrate as well as aminoguanidine significantly convalesce arsenic induced impairment of learning, memory, endothelial function, and alterations in various biochemical parameters. It may be concluded that arsenic induces endothelial dysfunction and dementia, whereas, sodium butyrate, a HDAC inhibitor as well as aminoguanidine, a selective iNOS inhibitor may be considered as potential agents for the management of arsenic induced endothelial dysfunction and dementia. - Highlights: • As has induced endothelial dysfunction (Edf) and vascular dementia (VaD). • As has increased oxidative stress, AChE activity and decreased serum NO. • Inhibitors of HDAC and iNOS have attenuated As induced Edf and VaD. • Both the inhibitors have attenuated As induced biochemical changes. • Inhibitor of HDAC and iNOS has shown good potential in

The calcineurin activity profiles of cyclosporin and tacrolimus are different in stable renal transplant patients

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Koefoed-Nielsen, PB; Karamperis, N; Hojskov, C

2006-01-01

Cyclosporin and tacrolimus remain the cornerstone immunosuppressive drugs in organ transplantation. Dosing and monitoring these drugs is based on pharmacokinetic protocols, but measuring a pharmacodynamic parameter, calcineurin phosphatase (CaN) activity, could be a valuable supplement...... in determining optimal doses. Forty stable renal transplant patients were investigated three times in a 6-month period. Blood samples were drawn at 0, 1, 2, 3 and 4 h after oral intake of tacrolimus (FK) or cyclosporin at days 1 and 180. At day 90, one blood sample at trough level (FK) or C2 level (cyclosporin A...... at days 1 and 180 were the same for both drugs. Furthermore, we found that patients treated with tacrolimus or cyclosporin displayed different calcineurin activity profiles. We found that cyclosporin displayed greater calcineurin inhibition than tacrolimus. We have demonstrated that the two drugs exert...

A tacrolimus-related immunosuppressant with reduced toxicity.

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Dumont, F J; Koprak, S; Staruch, M J; Talento, A; Koo, G; DaSilva, C; Sinclair, P J; Wong, F; Woods, J; Barker, J; Pivnichny, J; Singer, I; Sigal, N H; Williamson, A R; Parsons, W H; Wyvratt, M

1998-01-15

Tacrolimus (FK506) has potent immunosuppressive properties reflecting its ability to block the transcription of lymphokine genes in activated T cells through formation of a complex with FK506 binding protein-12, which inhibits the phosphatase activity of calcineurin. The clinical usefulness of tacrolimus is limited, however, by severe adverse effects, including neurotoxicity and nephrotoxicity. Although this toxicity, like immunosuppression, appears mechanistically related to the calcineurin inhibitory action of the drug, a large chemistry effort has been devoted to search for tacrolimus analogs with reduced toxicity but preserved immunosuppressive activity that might have enhanced therapeutic utility. Here, we report on the identification of such an analog, which was synthetically derived from ascomycin (ASC), the C21 ethyl analog of tacrolimus, by introducing an indole group at the C32 position. The profile of biological activity of indolyl-ASC was characterized in rodent models of immunosuppression and toxicity. Indolyl-ASC was found to exhibit an immunosuppressive potency equivalent to that of tacrolimus in T-cell activation in vitro and in murine transplant models, even though indolyl-ASC bound about 10 times less to intracellular FK506 binding protein-12 than tacrolimus or ASC. Further evaluation of indolyl-ASC revealed that it is threefold less potent than tacrolimus in inducing hypothermia, a response that may reflect neurotoxicity, and in causing gastrointestinal transit alterations in mice. Moreover, indolyl-ASC was at least twofold less nephrotoxic than tacrolimus upon 3-week oral treatment in rats. Altogether, these data indicate a modest but definite improvement in the therapeutic index for indolyl-ASC compared with tacrolimus in rodent models.

The role of basiliximab in the evolving renal transplantation immunosuppression protocol

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Paola Salis

2008-06-01

Full Text Available Paola Salis, Chiara Caccamo, Roberto Verzaro, Salvatore Gruttadauria, Mary ArteroDivision of Nephrology and Division of Abdominal Transplantation, Istituto Mediterraneo per i Trapianti e Terapie ad Alta Specializzazione, Palermo, ItalyAbstract: Basiliximab is a chimeric mouse-human monoclonal antibody directed against the alpha chain of the interleukin-2 (IL-2 receptor on activated T lymphocytes. It was shown in phase III trials to reduce the number and severity of acute rejection episodes in the first year following renal transplantation in adults and children, with a reasonable cost-benefit ratio. The drug does not increase the incidence of opportunistic infections or malignancies above baseline in patients treated with conventional calcineurin inhibitor-based immunosuppression. In the field of renal transplantation, basiliximab does not increase kidney or patient survival, despite the reduction in the number of rejection episodes. Basiliximab may reduce the incidence of delayed graft function. In comparison with lymphocyte-depleting antibodies basiliximab appears to have equal efficacy in standard immunological risk patients. Recently, IL-2 receptor monoclonal antibodies have been used with the objective of reducing or eliminating the more toxic elements of the standard immunosuppression protocol. Several trials have incorporated basiliximab in protocols designed to avoid or withdraw rapidly corticosteroids, as well as protocols which substitute target-of-rapamycin (TOR inhibitors for calcineurin inhibitors.Keywords: basiliximab, renal transplantation, IL-2 receptor antagonists, induction, immunosuppression, corticosteroids, calcineurin inhibitors

Early Conversion from Tacrolimus to Belatacept in a Highly Sensitized Renal Allograft Recipient with Calcineurin Inhibitor-Induced de novo Post-Transplant Hemolytic Uremic Syndrome

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Vasishta S. Tatapudi

2018-01-01

Full Text Available Background: Kidney transplantation is the first-line therapy for patients with end-stage renal disease since it offers greater long-term survival and improved quality of life when compared to dialysis. The advent of calcineurin inhibitor (CNI-based maintenance immunosuppression has led to a clinically significant decline in the rate of acute rejection and better short-term graft survival rates. However, these gains have not translated into improvement in long-term graft survival. CNI-related nephrotoxicity and metabolic side effects are thought to be partly responsible for this. Case Presentation: Here, we report the conversion of a highly sensitized renal transplant recipient with pretransplant donor-specific antibodies from tacrolimus to belatacept within 1 week of transplantation. This substitution was necessitated by the diagnosis of CNI-induced de novo post-transplant hemolytic uremic syndrome. Conclusion: Belatacept is a novel costimulation blocker that is devoid of the nephrotoxic properties of CNIs and has been shown to positively impact long-term graft survival and preserve renal allograft function in low-immunologic-risk kidney transplant recipients. Data regarding its use in patients who are broadly sensitized to human leukocyte antigens are scarce, and the increased risk of rejection associated with belatacept has been a deterrent to more widespread use of this immunosuppressive agent. This case serves as an example of a highly sensitized patient that has been successfully converted to a belatacept-based CNI-free regimen.

NMDA-induced potentiation of mGluR5 is mediated by activation of protein phosphatase 2B/calcineurin

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Alagarsamy, Sudar; Saugstad, Julie; Warren, Lee; Mansuy, Isabelle M.; Gereau, Robert W.; Conn, P. Jeffrey

2010-01-01

Previous reports have shown that activation of N-methyl-D-aspartate (NMDA) receptors potentiates responses to activation of the group I metabotropic glutamate receptor mGluR5 by reversing PKC-mediated desensitization of this receptor. NMDA-induced reversal of mGluR5 desensitization is dependent on activation of protein phosphatases. However, the specific protein phosphatase involved and the precise mechanism by which NMDA receptor activation reduces mGluR desensitization are not known. We have performed a series of molecular, biochemical, and genetic studies to show that NMDA-induced regulation of mGluR5 is dependent on activation of calcium-dependent protein phosphatase 2B/calcineurin (PP2B/CaN). Furthermore, we report that purified calcineurin directly dephosphorylates the C-terminal tail of mGluR5 at sites that are phosphorylated by PKC. Finally, immunoprecipitation and GST fusion protein pull-down experiments reveal that calcineurin interacts with mGluR5, suggesting that these proteins could be colocalized in a signaling complex. Taken together with previous studies, these data suggest that activation of NMDA receptors leads to activation of calcineurin and that calcineurin modulates mGluR5 function by directly dephosphorylating mGluR5 at PKC sites that are involved in desensitization of this receptor. 2005 Elsevier Ltd. All rights reserved. PMID:16005030

Influence of CYP3A5 and ABCB1 gene polymorphisms on calcineurin inhibitor-related neurotoxicity after hematopoietic stem cell transplantation.

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Yanagimachi, Masakatsu; Naruto, Takuya; Tanoshima, Reo; Kato, Hiromi; Yokosuka, Tomoko; Kajiwara, Ryosuke; Fujii, Hisaki; Tanaka, Fumiko; Goto, Hiroaki; Yagihashi, Tatsuhiko; Kosaki, Kenjiro; Yokota, Shumpei

2010-01-01

One severe side effect of calcineurin inhibitors (CNIs: such as cyclosporine [CsA] and tacrolimus [FK506]) is neurotoxicity. CNIs are substrates for CYP3A5 and P-glycoprotein (P-gp), encoded by ABCB1 gene. In the present study, we hypothesized that genetic variability in CYP3A5 and ABCB1 genes may be associated with CNI-related neurotoxicity. The effects of the polymorphisms, such as CYP3A5 A6986G, ABCB1 C1236T, G2677T/A, and C3435T, associated with CNI-related neurotoxicity were evaluated in 63 patients with hematopoietic stem cell transplantation.   Of the 63 cases, 15 cases developed CNI-related neurotoxicity. In the CsA patient group (n = 30), age (p = 0.008), hypertension (p = 0.017), renal dysfunction (p < 0.001), ABCB1 C1236T (p < 0.001), and G2677T/A (p = 0.014) were associated with neurotoxicities. The CC genotype at ABCB1 C1236T was associated with it, but not significantly so (p = 0.07), adjusted for age, hypertension, and renal dysfunction. In the FK506 patient group (n = 33), CYP3A5 A6986G (p < 0.001), and ABCB1 C1236T (p = 0.002) were associated with neurotoxicity. At least one A allele at CYP3A5 A6986G (expressor genotype) was strongly associated with it according to logistic regression analysis (p = 0.01; OR, 8.5; 95% CI, 1.4-51.4).   The polymorphisms in CYP3A5 and ABCB1 genes were associated with CNI-related neurotoxicity. This outcome is probably because of CYP3A5 or P-gp functions or metabolites of CNIs. © 2009 John Wiley & Sons A/S.

Screening for Selective Protein Inhibitors by Using the IANUS Peptide Array.

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Erdmann, Frank; Prell, Erik; Jahreis, Günther; Fischer, Gunter; Malešević, Miroslav

2018-04-16

Finding new road blacks: A peptidic inhibitor of calcineurin (CaN)-mediated nuclear factor of activated T cells (NFAT) dephosphorylation, which is developed through a template-assisted IANUS (Induced orgANisation of strUcture by matrix-assisted togethernesS) peptide array, is cell permeable and able to block the translocation of green fluorescent protein-NFAT fusion protein (GFP-NFAT) into the nucleus after stimulation. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

USING A DOE AND EIS TO EVALUATE THE SYNERGISTIC EFFECTS OF LOW TOXICITY INHIBITORS FOR MILD STEEL

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G. V. Bueno

2015-03-01

Full Text Available Abstract Inhibitors are widely used to prevent corrosion in cooling-water systems, and their protective performance can be enhanced by combination. The aim of this paper is to identify possible synergistic effects between four low toxicity substances used as corrosion inhibitors for mild steel in industrial cooling-water systems. Electrochemical measurements were obtained following a design of experiments (DOE where the independent variables were the inhibitors concentrations and the response variable the charge transfer resistance estimated from impedance diagrams. Potentiodynamic polarization curves show that all of them act as anodic corrosion inhibitors. Among the tested formulations, only the interaction between sodium molybdate and sodium tungstate showed statistically significant effects, indicating that they can perform better when used together. The results of this work show the importance of using a statistical tool when designing inhibitor mixtures.

Calcineurin regulates slow myosin, but not fast myosin or metabolic enzymes, during fast-to-slow transformation in rabbit skeletal muscle cell culture

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Meißner, Joachim D; Gros, Gerolf; Scheibe, Renate J; Scholz, Michael; Kubis, Hans-Peter

2001-01-01

The addition of cyclosporin A (500 ng ml−1) - an inhibitor of the Ca2+-calmodulin-regulated serine/threonine phosphatase calcineurin - to primary cultures of rabbit skeletal muscle cells had no influence on the expression of fast myosin heavy chain (MHC) isoforms MHCIIa and MHCIId at the level of protein and mRNA, but reduced the expression of slow MHCI mRNA. In addition, no influence of cyclosporin A on the expression of citrate synthase (CS) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA was found. The level of enzyme activity of CS was also not affected. When the Ca2+ ionophore A23187 (4 × 10−7m) was added to the medium, a partial fast-to-slow transformation occurred. The level of MHCI mRNA increased, and the level of MHCIId mRNA decreased. Cotreatment with cyclosporin A was able to prevent the upregulation of MHCI at the level of mRNA as well as protein, but did not reverse the decrease in MHCIId expression. The expression of MHCIIa was also not influenced by cyclosporin A. Cyclosporin A was not able to prevent the upregulation of CS mRNA under Ca2+ ionophore treatment and failed to reduce the increased enzyme activity of CS. The expression of GAPDH mRNA was reduced under Ca2+ ionophore treatment and was not altered under cotreatment with cyclosporin A. When the myotubes in the primary muscle culture were electrostimulated at 1 Hz for 15 min periods followed by pauses of 30 min, a partial fast-to-slow transformation was induced. Again, cotreatment with cyclosporin A prevented the upregulation of MHCI at the level of mRNA and protein without affecting MHCIId expression. The nuclear translocation of the calcineurin-regulated transcription factor nuclear factor of activated thymocytes (NFATc1) during treatment with Ca2+ ionophore, and the prevention of the translocation in the presence of cyclosporin A, were demonstrated immunocytochemically in the myotubes of the primary culture. The effects of cyclosporin A demonstrate the involvement of

Differential distribution of calcineurin Aα isoenzyme mRNA's in rat brain

NARCIS (Netherlands)

Buttini, M.; Limonta, S.; Luyten, M.; Boddeke, H.

1993-01-01

Specific antisense oligonucleotide probes for the α isoforms of the catalytic subunit (A-subunit) of calcineurin were prepared and the distribution of Aα1 and Aα2 mRNA's has been studied in rat brain using in situ hybridization histochemistry. Clear regional differences have been observed for the

Optimizing everolimus exposure when combined with calcineurin inhibitors in solid organ transplantation

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T. van Gelder (Teun); L. Fischer (Lutz); Shihab, F. (Fuad); M. Shipkova (Maria)

2017-01-01

textabstractThe mammalian target of rapamycin (mTOR) inhibitor everolimus is a narrow therapeutic index drug for which optimal exposure levels are essential. The consistent pharmacokinetic profile of everolimus allows trough concentration (C0) measurement to be an appropriate and reliable index for

Combining ChIP-chip and expression profiling to model the MoCRZ1 mediated circuit for Ca/calcineurin signaling in the rice blast fungus.

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Soonok Kim

2010-05-01

Full Text Available Significant progress has been made in defining the central signaling networks in many organisms, but collectively we know little about the downstream targets of these networks and the genes they regulate. To reconstruct the regulatory circuit of calcineurin signal transduction via MoCRZ1, a Magnaporthe oryzae C2H2 transcription factor activated by calcineurin dephosphorylation, we used a combined approach of chromatin immunoprecipitation - chip (ChIP-chip, coupled with microarray expression studies. One hundred forty genes were identified as being both a direct target of MoCRZ1 and having expression concurrently differentially regulated in a calcium/calcineurin/MoCRZ1 dependent manner. Highly represented were genes involved in calcium signaling, small molecule transport, ion homeostasis, cell wall synthesis/maintenance, and fungal virulence. Of particular note, genes involved in vesicle mediated secretion necessary for establishing host associations, were also found. MoCRZ1 itself was a target, suggesting a previously unreported autoregulation control point. The data also implicated a previously unreported feedback regulation mechanism of calcineurin activity. We propose that calcium/calcineurin regulated signal transduction circuits controlling development and pathogenicity manifest through multiple layers of regulation. We present results from the ChIP-chip and expression analysis along with a refined model of calcium/calcineurin signaling in this important plant pathogen.

Hepatocellular Toxicity Associated with Tyrosine Kinase Inhibitors: Mitochondrial Damage and Inhibition of Glycolysis

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Franziska Paech

2017-06-01

Full Text Available Tyrosine kinase inhibitors (TKIs are anticancer drugs with a lesser toxicity than classical chemotherapeutic agents but still with a narrow therapeutic window. While hepatotoxicity is known for most TKIs, underlying mechanisms remain mostly unclear. We therefore aimed at investigating mechanisms of hepatotoxicity for imatinib, sunitinib, lapatinib and erlotinib in vitro. We treated HepG2 cells, HepaRG cells and mouse liver mitochondria with TKIs (concentrations 1–100 μM for different periods of time and assessed toxicity. In HepG2 cells maintained with glucose (favoring glycolysis, all TKIs showed a time- and concentration-dependent cytotoxicity and, except erlotinib, a drop in intracellular ATP. In the presence of galactose (favoring mitochondrial metabolism, imatinib, sunitinib and erlotinib showed a similar toxicity profile as for glucose whereas lapatinib was less toxic. For imatinib, lapatinib and sunitinib, cytotoxicity increased in HepaRG cells induced with rifampicin, suggesting formation of toxic metabolites. In contrast, erlotinib was more toxic in HepaRG cells under basal than CYP-induced conditions. Imatinib, sunitinib and lapatinib reduced the mitochondrial membrane potential in HepG2 cells and in mouse liver mitochondria. In HepG2 cells, these compounds increased reactive oxygen species production, impaired glycolysis, and induced apoptosis. In addition, imatinib and sunitinib impaired oxygen consumption and activities of complex I and III (only imatinib, and reduced the cellular GSH pool. In conclusion, imatinib and sunitinib are mitochondrial toxicants after acute and long-term exposure and inhibit glycolysis. Lapatinib affected mitochondria only weakly and inhibited glycolysis, whereas the cytotoxicity of erlotinib could not be explained by a mitochondrial mechanism.

Suppression of Coronavirus Replication by Cyclophilin Inhibitors

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Takashi Sasaki

2013-05-01

Full Text Available Coronaviruses infect a variety of mammalian and avian species and cause serious diseases in humans, cats, mice, and birds in the form of severe acute respiratory syndrome (SARS, feline infectious peritonitis (FIP, mouse hepatitis, and avian infectious bronchitis, respectively. No effective vaccine or treatment has been developed for SARS-coronavirus or FIP virus, both of which cause lethal diseases. It has been reported that a cyclophilin inhibitor, cyclosporin A (CsA, could inhibit the replication of coronaviruses. CsA is a well-known immunosuppressive drug that binds to cellular cyclophilins to inhibit calcineurin, a calcium-calmodulin-activated serine/threonine-specific phosphatase. The inhibition of calcineurin blocks the translocation of nuclear factor of activated T cells from the cytosol into the nucleus, thus preventing the transcription of genes encoding cytokines such as interleukin-2. Cyclophilins are peptidyl-prolyl isomerases with physiological functions that have been described for many years to include chaperone and foldase activities. Also, many viruses require cyclophilins for replication; these include human immunodeficiency virus, vesicular stomatitis virus, and hepatitis C virus. However, the molecular mechanisms leading to the suppression of viral replication differ for different viruses. This review describes the suppressive effects of CsA on coronavirus replication.

Blockades of mitogen-activated protein kinase and calcineurin both change fibre-type markers in skeletal muscle culture

DEFF Research Database (Denmark)

Higginson, James; Wackerhage, Henning; Woods, Niall

2002-01-01

A and mitogen-activated protein kinase kinase (MEK1/2) blockade with U0126 upon myosin heavy chain (MHC) isoform mRNA levels and activities of metabolic enzymes after 1 day, 3 days and 7 days of treatment in primary cultures of spontaneously twitching rat skeletal muscle. U0126 treatment significantly decreased......Activation of either the calcineurin or the extracellular signal-regulated kinase (ERK1/2) pathway increases the percentage of slow fibres in vivo suggesting that both pathways can regulate fibre phenotypes in skeletal muscle. We investigated the effect of calcineurin blockade with cyclosporin...

Risk of severe hematologic toxicities in cancer patients treated with PARP inhibitors: results of monotherapy and combination therapy trials

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Alecu I

2018-02-01

Full Text Available Iulian Alecu, Tsveta Milenkova, Simon R Turner Research and Development, AstraZeneca UK Limited, Cambridge, UKThe tolerability profile of PARP inhibitors often includes hematologic toxicities, and the characterization of these adverse events is important to allow effective management by clinicians. Zhou et al1 recently carried out a meta-analysis of the incidence and relative risks of severe neutropenia, thrombocytopenia, and anemia events in 12 randomized controlled trials of PARP inhibitors, either as monotherapy or in combination with chemotherapy or radiotherapy. The authors concluded that olaparib resulted in a higher incidence of severe (common terminology criteria for adverse events [CTCAE] grade $3 neutropenia when compared with niraparib and veliparib; however, these conclusions are based on inappropriate and incomplete comparisons of hematologic toxicity with olaparib or veliparib in combination with myelotoxic chemotherapy versus niraparib monotherapy. While both monotherapy and combination therapy olaparib studies are discussed in the paper, the neutropenia analysis is based on olaparib data solely from studies in combination with paclitaxel or paclitaxel plus carboplatin. In order to inform the practicing clinician of the relative risk of hematologic toxicity associated with different PARP inhibitors, direct comparison needs to be conducted based on monotherapy, where applicable, as per the approved drug indication, otherwise the reader is given misleading information.View the original paper by Zhou et al.

Regional imbalanced activation of the calcineurin/BAD apoptotic pathway and the PI3K/Akt survival pathway after myocardial infarction.

Science.gov (United States)

Li, Tieluo; Kilic, Ahmet; Wei, Xufeng; Wu, Changfu; Schwartzbauer, Gary; Yankey, G Kwame; DeFilippi, Christopher; Bond, Meredith; Wu, Zhongjun J; Griffith, Bartley P

2013-06-05

The underlying molecular mechanisms of the remodeling after myocardial infarction (MI) remain unclear. The purpose of this study was to investigate the role of a survival pathway (PI3K/Akt) and an apoptosis pathway (calcineurin/BAD) in the remodeling after MI in a large animal model. Ten Dorset hybrid sheep underwent 25% MI in the left ventricle (LV, n=10). Five sheep were used as sham control. The regional strain was calculated from sonomicrometry. Apoptosis and the activation of the PI3K/Akt and calcineurin/BAD pathways were evaluated in the non-ischemic adjacent zone and the remote zone relative to infarct by immunoblotting, immunoprecipitation, and immunofluorescence staining. Dilation and dysfunction of LV were present at 12 weeks after MI. The regional strain in the adjacent zone was significantly higher than in the remote zone at 12 weeks (36.6 ± 4.0% vs 9.5 ± 3.6%, pBAD pathways were activated in the adjacent zone. Dephosphorylation and translocation of BAD were evident in the adjacent zone. Regional correlation between the strain and the expression of calcineurin/BAD indicated that the activation was strain-related (R(2)=0.46, 0.48, 0.39 for calcineurin, BAD, mitochondrial BAD, respectively, pBAD apoptotic pathways were concomitantly activated in the non-ischemic adjacent zone after MI. The calcineurin/BAD pathway is strain related and its imbalanced activation may be one of the causes of progressive remodeling after MI. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

CNP-1 (ARRD-17), a novel substrate of calcineurin, is critical for modulation of egg-laying and locomotion in response to food and lysine sensation in Caenorhabditis elegans.

Science.gov (United States)

Jee, Changhoon; Choi, Tae-Woo; Kalichamy, Karunambigai; Yee, Jong Zin; Song, Hyun-Ok; Ji, Yon Ju; Lee, Jungsoo; Lee, Jin Il; L'Etoile, Noelle D; Ahnn, Joohong; Lee, Sun-Kyung

2012-03-30

Calcineurin is a Ca(2+)/calmodulin-dependent protein phosphatase involved in calcium signaling pathways. In Caenorhabditis elegans, the loss of calcineurin activity causes pleiotropic defects including hyperadaptation of sensory neurons, hypersensation to thermal difference and hyper-egg-laying when worms are refed after starvation. In this study, we report on arrd-17 as calcineurin-interacting protein-1 (cnp-1), which is a novel molecular target of calcineurin. CNP-1 interacts with the catalytic domain of the C. elegans calcineurin A subunit, TAX-6, in a yeast two-hybrid assay and is dephosphorylated by TAX-6 in vitro. cnp-1 is expressed in ASK, ADL, ASH and ASJ sensory neurons as TAX-6. It acts downstream of tax-6 in regulation of locomotion and egg-laying after starvation, ASH sensory neuron adaptation and lysine chemotaxis, that is known to be mediated by ASK neurons. Altogether, our biochemical and genetic evidence indicates that CNP-1 is a direct target of calcineurin and required in stimulated egg-laying and locomotion after starvation, adaptation to hyperosmolarity and attraction to lysine, which is modulated by calcineurin. We suggest that the phosphorylation status of CNP-1 plays an important role in regulation of refed stimulating behaviors after starvation and attraction to amino acid, which provides valuable nutritious information. Copyright © 2012 Elsevier Ltd. All rights reserved.

Structure of Calmodulin Bound to a Calcineurin Peptide: A New Way of Making an Old Binding Mode

International Nuclear Information System (INIS)

Ye, Q.; Li, X.; Wong, A.; Wei, Q.; Jia, Z.

2006-01-01

Calcineurin is a calmodulin-binding protein in brain and the only serine/threonine protein phosphatase under the control of Ca 2+ /calmodulin (CaM), which plays a critical role in coupling Ca 2+ signals to cellular responses. CaM up-regulates the phosphatase activity of calcineurin by binding to the CaM-binding domain (CBD) of calcineurin subunit A. Here, we report crystal structural studies of CaM bound to a CBD peptide. The chimeric protein containing CaM and the CBD peptide forms an intimate homodimer, in which CaM displays a native-like extended conformation and the CBD peptide shows -helical structure. Unexpectedly, the N-terminal lobe from one CaM and the C-terminal lobe from the second molecule form a combined binding site to trap the peptide. Thus, the dimer provides two binding sites, each of which is reminiscent of the fully collapsed conformation of CaM commonly observed in complex with, for example, the myosin light chain kinase (MLCK) peptide. The interaction between the peptide and CaM is highly specific and similar to MLCK

CAMKII and calcineurin regulate the lifespan of Caenorhabditis elegans through the FOXO transcription factor DAF-16.

Science.gov (United States)

Tao, Li; Xie, Qi; Ding, Yue-He; Li, Shang-Tong; Peng, Shengyi; Zhang, Yan-Ping; Tan, Dan; Yuan, Zengqiang; Dong, Meng-Qiu

2013-06-25

The insulin-like signaling pathway maintains a relatively short wild-type lifespan in Caenorhabditis elegans by phosphorylating and inactivating DAF-16, the ortholog of the FOXO transcription factors of mammalian cells. DAF-16 is phosphorylated by the AKT kinases, preventing its nuclear translocation. Calcineurin (PP2B phosphatase) also limits the lifespan of C. elegans, but the mechanism through which it does so is unknown. Herein, we show that TAX-6•CNB-1 and UNC-43, the C. elegans Calcineurin and Ca(2+)/calmodulin-dependent kinase type II (CAMKII) orthologs, respectively, also regulate lifespan through DAF-16. Moreover, UNC-43 regulates DAF-16 in response to various stress conditions, including starvation, heat or oxidative stress, and cooperatively contributes to lifespan regulation by insulin signaling. However, unlike insulin signaling, UNC-43 phosphorylates and activates DAF-16, thus promoting its nuclear localization. The phosphorylation of DAF-16 at S286 by UNC-43 is removed by TAX-6•CNB-1, leading to DAF-16 inactivation. Mammalian FOXO3 is also regulated by CAMKIIA and Calcineurin. DOI:http://dx.doi.org/10.7554/eLife.00518.001.

Regulation of inward rectifier potassium current ionic channel remodeling by AT1 -Calcineurin-NFAT signaling pathway in stretch-induced hypertrophic atrial myocytes.

Science.gov (United States)

He, Jionghong; Xu, Yanan; Yang, Long; Xia, Guiling; Deng, Na; Yang, Yongyao; Tian, Ye; Fu, Zenan; Huang, Yongqi

2018-05-02

Previous studies have shown that the activation of angiotensin II receptor type I (AT 1 ) is attributed to cardiac remodeling stimulated by increased heart load, and that it is followed by the activation of the calcineurin-nuclear factor of activated T-cells (NFAT) signaling pathway. Additionally, AT 1 has been found to be a regulator of cardiocyte ionic channel remodeling, and calcineurin-NFAT signals participate in the regulation of cardiocyte ionic channel expression. A hypothesis therefore follows that stretch stimulation may regulate cardiocyte ionic channel remodeling by activating the AT 1 -calcineurin-NFAT pathway. Here, we investigated the role of the AT 1 -calcineurin-NFAT pathway in the remodeling of inward rectifier potassium (I k1 ) channel, in addition to its role in changing action potential, in stretch-induced hypertrophic atrial myocytes of neonatal rats. Our results showed that increased stretch significantly led to atrial myocytes hypertrophy; it also increased the activity of calcineurin enzymatic activity, which was subsequently attenuated by telmisartan or cyclosporine-A. The level of NFAT 3 protein in nuclear extracts, the mRNA and protein expression of Kir2.1 in whole cell extracts, and the density of I k1 were noticeably increased in stretched samples. Stretch stimulation significantly shortened the action potential duration (APD) of repolarization at the 50% and 90% level. Telmisartan, cyclosporine-A, and 11R-VIVIT attenuated stretch-induced alterations in the levels of NFAT 3 , mRNA and protein expression of Kir2.1, the density of I k1 , and the APD. Our findings suggest that the AT 1 -calcineurin-NFAT signaling pathway played an important role in regulating I k1 channel remodeling and APD change in stretch-induced hypertrophic atrial myocytes of neonatal rats. This article is protected by copyright. All rights reserved.

Acute toxicity of second generation HIV protease-inhibitors in combination with radiotherapy: a retrospective case series

International Nuclear Information System (INIS)

See, Alfred P; Zeng, Jing; Tran, Phuoc T; Lim, Michael

2011-01-01

There is little data on the safety of combining radiation therapy and human immunodeficiency virus (HIV) protease inhibitors to treat cancers in HIV-positive patients. We describe acute toxicities observed in a series of HIV-positive patients receiving modern radiation treatments, and compare patients receiving HIV protease inhibitors (PI) with patients not receiving HIV PIs. By reviewing the clinical records beginning January 1, 2009 from the radiation oncology department, we identified 29 HIV-positive patients who received radiation therapy to 34 body sites. Baseline information, treatment regimen, and toxicities were documented by review of medical records: patient age, histology and source of the primary tumor, HIV medication regimen, pre-radiation CD4 count, systemic chemotherapy, radiation therapy dose and fractionation, irradiated body region, toxicities, and duration of follow-up. Patients were grouped according to whether they received concurrent HIV PIs and compared using Pearson's chi-square test. At baseline, the patients in the two groups were similar with the exception of HIV medication regimens, CD4 count and presence of AIDS-defining malignancy. Patients taking concurrent PIs were more likely to be taking other HIV medications (p = 0.001) and have CD4 count >500 (p = 0.006). Patients taking PIs were borderline less likely to have an AIDS-defining malignancy (p = 0.06). After radiation treatment, 100 acute toxicities were observed and were equally common in both groups (64 [median 3 per patient, IQR 1-7] with PIs; 36 [median 3 per patient, IQR 2-3] without PIs). The observed toxicities were also equally severe in the two groups (Grades I, II, III respectively: 30, 30, 4 with PIs; 23, 13, 0 without PIs: p = 0.38). There were two cases that were stopped early, one in each group; these were not attributable to toxicity. In this study of recent radiotherapy in HIV-positive patients taking second generation PIs, no difference in toxicities was

Functional characterization of calcineurin homologs PsCNA1/PsCNB1 in Puccinia striiformis f. sp. tritici using a host-induced RNAi system.

Directory of Open Access Journals (Sweden)

Hong Zhang

Full Text Available Calcineurin plays a key role in morphogenesis, pathogenesis and drug resistance in most fungi. However, the function of calcineurin genes in Puccinia striiformis f. sp. tritici (Pst is unclear. We identified and characterized the calcineurin genes PsCNA1 and PsCNB1 in Pst. Phylogenetic analyses indicate that PsCNA1 and PsCNB1 form a calcium/calmodulin regulated protein phosphatase belonging to the calcineurin heterodimers composed of subunits A and B. Quantitative RT-PCR analyses revealed that both PsCNA1 and PsCNB1 expression reached their maximum in the stage of haustorium formation, which is one day after inoculation. Using barely stripe mosaic virus (BSMV as a transient expression vector in wheat, the expression of PsCNA1 and PsCNB1 in Pst was suppressed, leading to slower extension of fungal hyphae and reduced production of urediospores. The immune-suppressive drugs cyclosporin A and FK506 markedly reduced the germination rates of urediospores, and when germination did occur, more than two germtubes were produced. These results suggest that the calcineurin signaling pathway participates in stripe rust morphogenetic differentiation, especially the formation of haustoria during the early stage of infection and during the production of urediospores. Therefore PsCNA1 and PsCNB1 can be considered important pathogenicity genes involved in the wheat-Pst interaction.

The calcineurin activity profiles of cyclosporin and tacrolimus are different in stable renal transplant patients

DEFF Research Database (Denmark)

Koefoed-Nielsen, Pernille Bundgaard; Karamperis, Nikolaos; Jørgensen, Kaj Anker

2006-01-01

in determining optimal doses. Forty stable renal transplant patients were investigated three times in a 6-month period. Blood samples were drawn at 0, 1, 2, 3 and 4 h after oral intake of tacrolimus (FK) or cyclosporin at days 1 and 180. At day 90, one blood sample at trough level (FK) or C2 level (cyclosporin A...... significantly different effects on calcineurin activity in renal transplant patients with stable, well-functioning grafts and that tacrolimus-treated patients can maintain good, stable graft function with minimal CaN inhibition.......Cyclosporin and tacrolimus remain the cornerstone immunosuppressive drugs in organ transplantation. Dosing and monitoring these drugs is based on pharmacokinetic protocols, but measuring a pharmacodynamic parameter, calcineurin phosphatase (CaN) activity, could be a valuable supplement...

Calcineurin Inhibition Blocks Within-, but Not Between-Session Fear Extinction in Mice

Science.gov (United States)

Almeida-Corrêa, Suellen; Moulin, Thiago C.; Carneiro, Clarissa F. D.; Gonçalves, Marina M. C.; Junqueira, Lara S.; Amaral, Olavo B.

2015-01-01

Memory extinction involves the formation of a new associative memory that inhibits a previously conditioned association. Nonetheless, it could also depend on weakening of the original memory trace if extinction is assumed to have multiple components. The phosphatase calcineurin (CaN) has been described as being involved in extinction but not in…

Tonic 5nM DA stabilizes neuronal output by enabling bidirectional activity-dependent regulation of the hyperpolarization activated current via PKA and calcineurin.

Science.gov (United States)

Krenz, Wulf-Dieter C; Rodgers, Edmund W; Baro, Deborah J

2015-01-01

Volume transmission results in phasic and tonic modulatory signals. The actions of tonic dopamine (DA) at type 1 DA receptors (D1Rs) are largely undefined. Here we show that tonic 5nM DA acts at D1Rs to stabilize neuronal output over minutes by enabling activity-dependent regulation of the hyperpolarization activated current (I h). In the presence but not absence of 5nM DA, I h maximal conductance (G max) was adjusted according to changes in slow wave activity in order to maintain spike timing. Our study on the lateral pyloric neuron (LP), which undergoes rhythmic oscillations in membrane potential with depolarized plateaus, demonstrated that incremental, bi-directional changes in plateau duration produced corresponding alterations in LP I hG max when preparations were superfused with saline containing 5nM DA. However, when preparations were superfused with saline alone there was no linear correlation between LP I hGmax and duty cycle. Thus, tonic nM DA modulated the capacity for activity to modulate LP I h G max; this exemplifies metamodulation (modulation of modulation). Pretreatment with the Ca2+-chelator, BAPTA, or the specific PKA inhibitor, PKI, prevented all changes in LP I h in 5nM DA. Calcineurin inhibitors blocked activity-dependent changes enabled by DA and revealed a PKA-mediated, activity-independent enhancement of LP I hG max. These data suggested that tonic 5nM DA produced two simultaneous, PKA-dependent effects: a direct increase in LP I h G max and a priming event that permitted calcineurin regulation of LP I h. The latter produced graded reductions in LP I hG max with increasing duty cycles. We also demonstrated that this metamodulation preserved the timing of LP's first spike when network output was perturbed with bath-applied 4AP. In sum, 5nM DA permits slow wave activity to provide feedback that maintains spike timing, suggesting that one function of low-level, tonic modulation is to stabilize specific features of a dynamic output.

Tonic 5nM DA stabilizes neuronal output by enabling bidirectional activity-dependent regulation of the hyperpolarization activated current via PKA and calcineurin.

Directory of Open Access Journals (Sweden)

Wulf-Dieter C Krenz

Full Text Available Volume transmission results in phasic and tonic modulatory signals. The actions of tonic dopamine (DA at type 1 DA receptors (D1Rs are largely undefined. Here we show that tonic 5nM DA acts at D1Rs to stabilize neuronal output over minutes by enabling activity-dependent regulation of the hyperpolarization activated current (I h. In the presence but not absence of 5nM DA, I h maximal conductance (G max was adjusted according to changes in slow wave activity in order to maintain spike timing. Our study on the lateral pyloric neuron (LP, which undergoes rhythmic oscillations in membrane potential with depolarized plateaus, demonstrated that incremental, bi-directional changes in plateau duration produced corresponding alterations in LP I hG max when preparations were superfused with saline containing 5nM DA. However, when preparations were superfused with saline alone there was no linear correlation between LP I hGmax and duty cycle. Thus, tonic nM DA modulated the capacity for activity to modulate LP I h G max; this exemplifies metamodulation (modulation of modulation. Pretreatment with the Ca2+-chelator, BAPTA, or the specific PKA inhibitor, PKI, prevented all changes in LP I h in 5nM DA. Calcineurin inhibitors blocked activity-dependent changes enabled by DA and revealed a PKA-mediated, activity-independent enhancement of LP I hG max. These data suggested that tonic 5nM DA produced two simultaneous, PKA-dependent effects: a direct increase in LP I h G max and a priming event that permitted calcineurin regulation of LP I h. The latter produced graded reductions in LP I hG max with increasing duty cycles. We also demonstrated that this metamodulation preserved the timing of LP's first spike when network output was perturbed with bath-applied 4AP. In sum, 5nM DA permits slow wave activity to provide feedback that maintains spike timing, suggesting that one function of low-level, tonic modulation is to stabilize specific features of a dynamic output.

Pulmonary Toxicity of Cholinesterase Inhibitors

National Research Council Canada - National Science Library

Hilmas, Corey; Adler, Michael; Baskin, Steven I; Gupta, Ramesh C

2006-01-01

.... Whereas nerve agents were produced primarily for military deployment, other cholinesterase inhibitors were used for treating conditions such as myasthenia gravis and as pretreaunents for nerve agent exposure...

Effects of a phospholipase A2 inhibitor on uptake and toxicity of liposomes containing plant phosphatidylinositol

International Nuclear Information System (INIS)

Jett, M.; Alving, C.R.

1986-01-01

Plant phosphatidylinositol (PI) has been shown by us to have a direct cytotoxic effect on cultured tumor cells but not on normal cells. Synthetic PI containing 14 C-linoleic acid in the sn-2 position, also showed the same pattern of selective cytotoxicity. When the metabolic fate of synthetic PI was examined with tumor cells, the radioactivity which no longer occurred as PI, was found as either products of phospholipase A 2 (93%, free fatty acids and phosphatidylcholine) or phospholipase C (7%, diglycerides). Uptake of liposomal PI was directly correlated with cytotoxicity. They tested a variety of inhibitors to see the effect on uptake and/or cytotoxicity of plant PI. General metabolic inhibitors such as metrizamide or sodium azide did not alter cellular uptake of the plant PI liposomes. Inhibitors of lipoxygenase formation, such as indomethacin, also did not alter the uptake or cytotoxicity induced by plant PI. Quinacrine, an inhibitor of phospholipase A 2 , decreased the uptake of the PI containing liposomes to 50% of that seen in the presence or absence of any other inhibitor. Although quinacrine is itself toxic to cells, at low concentrations of quinacrine, plant PI did not show the same degree of cytotoxicity as in the absence of quinacrine. These data are compatible with the hypothesis that plant PI exerts cytotoxicity by serving as a substrate for phospholipase A 2

BCR Signaling Inhibitors: an Overview of Toxicities Associated with Ibrutinib and Idelalisib in Patients with Chronic Lymphocytic Leukemia

Science.gov (United States)

Falchi, Lorenzo; Baron, Jessica M.; Orlikowski, Carrie Anne; Ferrajoli, Alessandra

2016-01-01

The B-cell receptor (BCR) signaling inhibitors ibrutinib and idelalisib are revolutionizing the treatment of chronic lymphocytic leukemia (CLL) and other B-cell malignancies. These oral agents, both alone and in combination with other drugs, have shown remarkable clinical activity in relapsed or refractory CLL across all risk groups, and have been approved by the Food and Drug Administration for this indication. Preliminary data suggest that an even greater benefit can be expected in treatment-naïve CLL patients. Both ibrutinib and idelalisib are well tolerated by most patients, including older, frailer individuals. Toxicities are usually mild and self-resolving. Clinicians must, however, be aware of a number of peculiar adverse events, the effects of which can be severe enough to limit the clinical use of these agents. In this review, we survey the salient aspects of the pharmacology and clinical experience with the use of BCR signaling inhibitors for the treatment of patients with CLL. We next focus on both the most common and the most clinically significant toxicities associated with these drugs. PMID:26977270

The neuronal nitric oxide synthase inhibitor NANT blocks acetaminophen toxicity and protein nitration in freshly isolated hepatocytes.

Science.gov (United States)

Banerjee, Sudip; Melnyk, Stepan B; Krager, Kimberly J; Aykin-Burns, Nukhet; Letzig, Lynda G; James, Laura P; Hinson, Jack A

2015-12-01

3-Nitrotyrosine (3NT) in liver proteins of mice treated with hepatotoxic doses of acetaminophen (APAP) has been postulated to be causative in toxicity. Nitration is by a reactive nitrogen species formed from nitric oxide (NO). The source of the NO is unclear. iNOS knockout mice were previously found to be equally susceptible to APAP toxicity as wildtype mice and iNOS inhibitors did not decrease toxicity in mice or in hepatocytes. In this work we examined the potential role of nNOS in APAP toxicity in hepatocytes using the specific nNOS inhibitor NANT (10 µM)(N-[(4S)-4-amino-5-[(2-aminoethyl)amino]pentyl]-N'-nitroguanidinetris (trifluoroacetate)). Primary hepatocytes (1 million/ml) from male B6C3F1 mice were incubated with APAP (1mM). Cells were removed and assayed spectrofluorometrically for reactive nitrogen and oxygen species using diaminofluorescein (DAF) and Mitosox red, respectively. Cytotoxicity was determined by LDH release into media. Glutathione (GSH, GSSG), 3NT, GSNO, acetaminophen-cysteine adducts, NAD, and NADH were measured by HPLC. APAP significantly increased cytotoxicity at 1.5-3.0 h. The increase was blocked by NANT. NANT did not alter APAP mediated GSH depletion or acetaminophen-cysteine adducts in proteins which indicated that NANT did not inhibit metabolism. APAP significantly increased spectroflurometric evidence of reactive nitrogen and oxygen formation at 0.5 and 1.0 h, respectively, and increased 3NT and GSNO at 1.5-3.0 h. These increases were blocked by NANT. APAP dramatically increased NADH from 0.5-3.0 h and this increase was blocked by NANT. Also, APAP decreased the Oxygen Consumption Rate (OCR), decreased ATP production, and caused a loss of mitochondrial membrane potential, which were all blocked by NANT. Copyright © 2015 Elsevier Inc. All rights reserved.

Calcineurin inhibitors recruit protein kinases JAK2 and JNK, TLR signaling and the UPR to activate NF-κB-mediated inflammatory responses in kidney tubular cells

International Nuclear Information System (INIS)

González-Guerrero, Cristian; Ocaña-Salceda, Carlos; Berzal, Sergio; Carrasco, Susana; Fernández-Fernández, Beatriz

2013-01-01

The calcineurin inhibitors (CNIs) cyclosporine (CsA) and tacrolimus are key drugs in current immunosuppressive regimes for solid organ transplantation. However, they are nephrotoxic and promote death and profibrotic responses in tubular cells. Moreover, renal inflammation is observed in CNI nephrotoxicity but the mechanisms are poorly understood. We have now studied molecular pathways leading to inflammation elicited by the CNIs in cultured and kidney tubular cells. Both CsA and tacrolimus elicited a proinflammatory response in tubular cells as evidenced by a transcriptomics approach. Transcriptomics also suggested several potential pathways leading to expression of proinflammatory genes. Validation and functional studies disclosed that in tubular cells, CNIs activated protein kinases such as the JAK2/STAT3 and TAK1/JNK/AP-1 pathways, TLR4/Myd88/IRAK signaling and the Unfolded Protein Response (UPR) to promote NF-κB activation and proinflammatory gene expression. CNIs also activated an Nrf2/HO-1-dependent compensatory response and the Nrf2 activator sulforaphane inhibited JAK2 and JNK activation and inflammation. A murine model of CsA nephrotoxicity corroborated activation of the proinflammatory pathways identified in cell cultures. Human CNIs nephrotoxicity was also associated with NF-κB, STAT3 and IRE1α activation. In conclusion, CNIs recruit several intracellular pathways leading to previously non-described proinflammatory actions in renal tubular cells. Identification of these pathways provides novel clues for therapeutic intervention to limit CNIs nephrotoxicity. - Highlights: • Molecular mechanisms modulating CNI renal inflammation were investigated. • Kinases, immune receptors and ER stress mediate the inflammatory response to CNIs. • Several intracellular pathways activate NF-κB in CNIs-treated tubular cells. • A NF-κB-dependent cytokine profile characterizes CNIs-induced inflammation. • CNI nephrotoxicity was associated to inflammatory

Optimising the use of mTOR inhibitors in renal transplantation.

Science.gov (United States)

Russ, Graeme R

2013-11-20

Renal transplantation is the treatment of choice for end-stage renal failure. Although advances in immunosuppression have led to improvements in short-term outcomes, graft survival beyond 5 to 10 years has not improved. One of the major causes of late renal allograft failure is chronic allograft nephropathy, a component of which is nephrotoxicity from the use of calcineurin inhibitors (CNIs). In addition, premature patient death is a major limitation of renal transplantation and the major causes are cancer, cardiovascular disease and infection. CNI-free immunosuppressive regimens based on mammalian target of rapamycin (mTOR) inhibitors have been trial led over the last few years and have defined the rational use of these agents. Conversion from a CNI-based to an mTOR-inhibitor-based regimen has been successful at improving renal function for a number of years after conversion, although long-term survival outcomes are still awaited. The studies suggest that the safest and most effective time to convert is between 1 and 6 months after transplant. In addition, mTOR-inhibitor-based regimens have been shown to be associated with lower rates of post-transplant malignancy and less cytomegalovirus infection, which may add further to the appeal of this approach.

Inhibition of calcineurin phosphatase promotes exocytosis of renin from juxtaglomerular cells

DEFF Research Database (Denmark)

Madsen, Kirsten; Friis, Ulla Glenert; Gooch, Jennifer L

2010-01-01

. Simultaneous exposure to EGTA and CsA had no additive effect. The protein kinase A (PKA) blocker RpcAMPs had no effect on the CsA-induced increase in membrane capacitance. Intra- and extracellular application of tacrolimus did not alter membrane capacitance. A calmodulin antagonist (calmidazolium) and Cs...... after CsA treatment of the A-alpha knockout, while renin mRNA was suppressed. We conclude that calcineurin and calcium/calmodulin suppress exocytosis of renin from juxtaglomerular cells independent of PKA....

Reduced systemic toxicity and preserved vestibular toxicity following co-treatment with nitriles and CYP2E1 inhibitors: a mouse model for hair cell loss.

Science.gov (United States)

Saldaña-Ruíz, Sandra; Boadas-Vaello, Pere; Sedó-Cabezón, Lara; Llorens, Jordi

2013-10-01

Several nitriles, including allylnitrile and cis-crotononitrile, have been shown to be ototoxic and cause hair cell degeneration in the auditory and vestibular sensory epithelia of mice. However, these nitriles can also be lethal due in large part to the microsomal metabolic release of cyanide, which is mostly dependent on the activity of the 2E1 isoform of the cytochrome P450 (CYP2E1). In this study, we co-administered mice with a nitrile and, to reduce their lethal effects, a selective CYP2E1 inhibitor: diallylsulfide (DAS) or trans-1,2-dichloroethylene (TDCE). Both in female 129S1/SvImJ (129S1) mice co-treated with DAS and cis-crotononitrile and in male RjOrl:Swiss/CD-1 (Swiss) mice co-treated with TDCE and allylnitrile, the nitrile caused a dose-dependent loss of vestibular function, as assessed by a specific behavioral test battery, and of hair cells, as assessed by hair bundle counts using scanning electron microscopy. In the experiments, the CYP2E1 inhibitors provided significant protection against the lethal effects of the nitriles and did not diminish the vestibular toxicity as assessed by behavioral effects in comparison to animals receiving no inhibitor. Additional experiments using a single dose of allylnitrile demonstrated that TDCE does not cause hair cell loss on its own and does not modify the vestibular toxicity of the nitrile in either male or female 129S1 mice. In all the experiments, high vestibular dysfunction scores in the behavioral test battery predicted extensive to complete loss of hair cells in the utricles. This provides a means of selecting animals for subsequent studies of vestibular hair cell regeneration or replacement.

Low-dose tacrolimus combined with donor-derived mesenchymal stem cells after renal transplantation: a prospective, non-randomized study

OpenAIRE

Pan, Guang-hui; Chen, Zheng; Xu, Lu; Zhu, Jing-hui; Xiang, Peng; Ma, Jun-jie; Peng, Yan-wen; Li, Guang-hui; Chen, Xiao-yong; Fang, Jia-li; Guo, Yu-he; Zhang, Lei; Liu, Long-shan

2016-01-01

Calcineurin inhibitors, including tacrolimus, are largely responsible for advances in allotransplantation. However, the nephrotoxicity associated with these immunosuppressants impairs patients' long-term survival after renal allograft. Therefore, novel regimens that minimize or even eliminate calcineurin inhibitors could improve transplantation outcomes. In this pilot study, we investigated the use of low-dose tacrolimus in combination with mesenchymal stem cells (MSCs), which are immunosuppr...

Pharmacokinetic drivers of toxicity for basic molecules: Strategy to lower pKa results in decreased tissue exposure and toxicity for a small molecule Met inhibitor

International Nuclear Information System (INIS)

Diaz, Dolores; Ford, Kevin A.; Hartley, Dylan P.; Harstad, Eric B.; Cain, Gary R.; Achilles-Poon, Kirsten; Nguyen, Trung; Peng, Jing; Zheng, Zhong; Merchant, Mark; Sutherlin, Daniel P.; Gaudino, John J.; Kaus, Robert; Lewin-Koh, Sock C.; Choo, Edna F.; Liederer, Bianca M.; Dambach, Donna M.

2013-01-01

Several toxicities are clearly driven by free drug concentrations in plasma, such as toxicities related to on-target exaggerated pharmacology or off-target pharmacological activity associated with receptors, enzymes or ion channels. However, there are examples in which organ toxicities appear to correlate better with total drug concentrations in the target tissues, rather than with free drug concentrations in plasma. Here we present a case study in which a small molecule Met inhibitor, GEN-203, with significant liver and bone marrow toxicity in preclinical species was modified with the intention of increasing the safety margin. GEN-203 is a lipophilic weak base as demonstrated by its physicochemical and structural properties: high LogD (distribution coefficient) (4.3) and high measured pKa (7.45) due to the basic amine (N-ethyl-3-fluoro-4-aminopiperidine). The physicochemical properties of GEN-203 were hypothesized to drive the high distribution of this compound to tissues as evidenced by a moderately-high volume of distribution (Vd > 3 l/kg) in mouse and subsequent toxicities of the compound. Specifically, the basicity of GEN-203 was decreased through addition of a second fluorine in the 3-position of the aminopiperidine to yield GEN-890 (N-ethyl-3,3-difluoro-4-aminopiperidine), which decreased the volume of distribution of the compound in mouse (Vd = 1.0 l/kg), decreased its tissue drug concentrations and led to decreased toxicity in mice. This strategy suggests that when toxicity is driven by tissue drug concentrations, optimization of the physicochemical parameters that drive tissue distribution can result in decreased drug concentrations in tissues, resulting in lower toxicity and improved safety margins. -- Highlights: ► Lower pKa for a small molecule: reduced tissue drug levels and toxicity. ► New analysis tools to assess electrostatic effects and ionization are presented. ► Chemical and PK drivers of toxicity can be leveraged to improve safety.

Prokineticin-1 (PROK1) modulates interleukin (IL)-11 expression via prokineticin receptor 1 (PROKR1) and the calcineurin/NFAT signalling pathway.

Science.gov (United States)

Cook, Ian H; Evans, Jemma; Maldonado-Pérez, David; Critchley, Hilary O; Sales, Kurt J; Jabbour, Henry N

2010-03-01

Prokineticin-1 (PROK1) is a multifunctional secreted protein which signals via the G-protein coupled receptor, PROKR1. Previous data from our laboratory using a human genome survey microarray showed that PROK1-prokineticin receptor 1 (PROKR1) signalling regulates numerous genes important for establishment of early pregnancy, including the cytokine interleukin (IL)-11. Here, we have shown that PROK1-PROKR1 induces the expression of IL-11 in PROKR1 Ishikawa cells and first trimester decidua via the calcium-calcineurin signalling pathway in a guanine nucleotide-binding protein (G(q/11)), extracellular signal-regulated kinases, Ca(2+) and calcineurin-nuclear factor of activated T cells dependent manner. Conversely, treatment of human decidua with a lentiviral miRNA to abolish endogenous PROK1 expression results in a significant reduction in IL-11 expression and secretion. Importantly, we have also shown a regulatory role for the regulator of calcineurin 1 isoform 4 (RCAN1-4). Overexpression of RCAN1-4 in PROKR1 Ishikawa cells using an adenovirus leads to a reduction in PROK1 induced IL-11 indicating that RCAN1-4 is a negative regulator in the calcineurin-mediated signalling to IL-11. Finally, we have shown the potential for both autocrine and paracrine signalling in the human endometrium by co-localizing IL-11, IL-11Ralpha and PROKR1 within the stromal and glandular epithelial cells of non-pregnant endometrium and first trimester decidua. Overall we have identified and characterized the signalling components of a novel PROK1-PROKR1 signalling pathway regulating IL-11.

Calcium-activated-calcineurin reduces the In vitro and In vivo sensitivity of fluconazole to Candida albicans via Rta2p.

Directory of Open Access Journals (Sweden)

Yu Jia

Full Text Available Due to the emergence of drug-resistance, first-line therapy with fluconazole (FLC increasingly resulted in clinical failure for the treatment of candidemia. Our previous studies found that in vitro RTA2 was involved in the calcineurin-mediated resistance to FLC in C. albicans. In this study, we found that calcium-activated-calcineurin significantly reduced the in vitro sensitivity of C. albicans to FLC by blocking the impairment of FLC to the plasma membrane via Rta2p. Furthermore, we found that RTA2 itself was not involved in C. albicans virulence, but the disruption of RTA2 dramatically increased the therapeutic efficacy of FLC in a murine model of systemic candidiasis. Conversely, both re-introduction of one RTA2 allele and ectopic expression of RTA2 significantly reduced FLC efficacy in a mammalian host. Finally, we found that calcium-activated-calcineurin, through its target Rta2p, dramatically reduced the efficacy of FLC against candidemia. Given the critical roles of Rta2p in controlling the efficacy of FLC, Rta2p can be a potential drug target for antifungal therapies.

Endothelial Regulator of Calcineurin 1 Promotes Barrier Integrity and Modulates Histamine-Induced Barrier Dysfunction in Anaphylaxis

DEFF Research Database (Denmark)

Ballesteros-Martinez, Constanza; Mendez-Barbero, Nerea; Montalvo-Yuste, Alma

2017-01-01

Anaphylaxis, the most serious and life-threatening allergic reaction, produces the release of inflammatory mediators by mast cells and basophils. Regulator of calcineurin 1 (Rcan1) is a negative regulator of mast-cell degranulation. The action of mediators leads to vasodilation and an increase in...

Long-term habituation of the gill-withdrawal reflex in Aplysia requires gene transcription, calcineurin and L-type voltage-gated calcium channels

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Joseph eEsdin

2010-11-01

Full Text Available Although habituation is possibly the simplest form of learning, we still do not fully understand the neurobiological basis of habituation in any organism. To advance the goal of a comprehensive understanding of habituation, we have studied long-term habituation (LTH of the gill-withdrawal reflex (GWR in the marine snail Aplysia californica. Previously, we showed that habituation of the GWR in a reduced preparation lasts for up to 12 hr, and depends on protein synthesis, as well as activation of protein phosphatases 1 and 2A and postsynaptic glutamate receptors. Here, we have used the reduced preparation to further analyze the mechanisms of LTH in Aplysia. We found that LTH of the GWR depends on RNA synthesis because it was blocked by both the irreversible transcriptional inhibitor actinomycin-D and the reversible transcriptional inhibitor, 5,6-dichlorobenzimidazole riboside (DRB. In addition, LTH requires activation of protein phosphatase 2B (calcineurin, because it was disrupted by ascomycin. Finally, LTH was blocked by nitrendipine, which indicates that activation of L-type voltage-gated Ca2+ channels is required for this form of learning. Together with our previous results, the present results indicate that exclusively presynaptic mechanisms, although possibly sufficient for short-term habituation, are insufficient for LTH. Rather, LTH must involve postsynaptic, as well as presynaptic, mechanisms.

Small Quaternary Inhibitors K298 and K524: Cholinesterases Inhibition, Absorption, Brain Distribution, and Toxicity.

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Karasova, Jana Zdarova; Hroch, Milos; Musilek, Kamil; Kuca, Kamil

2016-02-01

Inhibitors of acetylcholinesterase (AChE) may be used in the treatment of various cholinergic deficits, among them being myasthenia gravis (MG). This paper describes the first in vivo data for promising small quaternary inhibitors (K298 and K524): acute toxicity study, cholinesterase inhibition, absorption, and blood-brain barrier penetration. The newly prepared AChE inhibitors (bis-quinolinium and quinolinium compounds) possess a positive charge in the molecule which ensures that anti-AChE action is restricted to peripheral effect. HPLC-MS was used for determination of real plasma and brain concentration in the pharmacokinetic part of the study, and standard non-compartmental analysis was performed. The maximum plasma concentrations were attained at 30 min (K298; 928.76 ± 115.20 ng/ml) and 39 min (K524; 812.40 ± 54.96 ng/ml) after i.m. Both compounds are in fact able to target the central nervous system. It seems that the difference in the CNS distribution profile depends on an active efflux system. The K524 brain concentration was actively decreased to below an effective level; in contrast, K298 progressively accumulated in brain tissue. Peripheral AChE inhibitors are still first-line treatment in the mild forms of MG. Commonly prescribed carbamates have many severe side effects related to AChE carbamylation. The search for new treatment strategies is still important. Unlike carbamates, these new compounds target AChE via apparent π-π or π-cationic interaction aside at the AChE catalytic site.

Calcineurin Orchestrates Hyphal Growth, Septation, Drug Resistance and Pathogenesis of Aspergillus fumigatus: Where Do We Go from Here?

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Praveen R Juvvadi

2015-12-01

Full Text Available Studies on fungal pathogens belonging to the ascomycota phylum are critical given the ubiquity and frequency with which these fungi cause infections in humans. Among these species, Aspergillus fumigatus causes invasive aspergillosis, a leading cause of death in immunocompromised patients. Fundamental to A. fumigatus pathogenesis is hyphal growth. However, the precise mechanisms underlying hyphal growth and virulence are poorly understood. Over the past 10 years, our research towards the identification of molecular targets responsible for hyphal growth, drug resistance and virulence led to the elucidation of calcineurin as a key signaling molecule governing these processes. In this review, we summarize our salient findings on the significance of calcineurin for hyphal growth and septation in A. fumigatus and propose future perspectives on exploiting this pathway for designing new fungal-specific therapeutics.

Pituitary adenylate cyclase activating polypeptide (PACAP signalling exerts chondrogenesis promoting and protecting effects: implication of calcineurin as a downstream target.

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Tamás Juhász

Full Text Available Pituitary adenylate cyclase activating polypeptide (PACAP is an important neurotrophic factor influencing differentiation of neuronal elements and exerting protecting role during traumatic injuries or inflammatory processes of the central nervous system. Although increasing evidence is available on its presence and protecting function in various peripheral tissues, little is known about the role of PACAP in formation of skeletal components. To this end, we aimed to map elements of PACAP signalling in developing cartilage under physiological conditions and during oxidative stress. mRNAs of PACAP and its receptors (PAC1,VPAC1, VPAC2 were detectable during differentiation of chicken limb bud-derived chondrogenic cells in micromass cell cultures. Expression of PAC1 protein showed a peak on days of final commitment of chondrogenic cells. Administration of either the PAC1 receptor agonist PACAP 1-38, or PACAP 6-38 that is generally used as a PAC1 antagonist, augmented cartilage formation, stimulated cell proliferation and enhanced PAC1 and Sox9 protein expression. Both variants of PACAP elevated the protein expression and activity of the Ca-calmodulin dependent Ser/Thr protein phosphatase calcineurin. Application of PACAPs failed to rescue cartilage formation when the activity of calcineurin was pharmacologically inhibited with cyclosporine A. Moreover, exogenous PACAPs prevented diminishing of cartilage formation and decrease of calcineurin activity during oxidative stress. As an unexpected phenomenon, PACAP 6-38 elicited similar effects to those of PACAP 1-38, although to a different extent. On the basis of the above results, we propose calcineurin as a downstream target of PACAP signalling in differentiating chondrocytes either in normal or pathophysiological conditions. Our observations imply the therapeutical perspective that PACAP can be applied as a natural agent that may have protecting effect during joint inflammation and/or may promote

The role of mTOR inhibitors in the prevention of organ rejection in adult liver transplant patients: a focus on everolimus

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Casanovas T

2014-06-01

Full Text Available Teresa Casanovas Liver Transplant Unit, Bellvitge University Hospital, Barcelona, Spain Abstract: Liver transplantation remains the therapy of choice for patients with end-stage liver disease and in selected cases of hepatocellular carcinoma. While short-term allograft survival has improved significantly in recent years, there has been little improvement in long-term survival after liver transplantation. A growing body of evidence on factors influencing the long-term outcomes and the safety profiles of existing immunosuppressive agents after liver transplant points to a need to continue searching for alternative strategies. The calcineurin inhibitors (CNIs (cyclosporine and tacrolimus currently represent the backbone of most immunosuppressor regimens. They have had a revolutionary effect on the overall success of transplantation, as is reflected in greatly reduced rates of acute rejection. However, the CNIs have significant toxicities that produce renal dysfunction, cardiovascular disease, and other unwanted effects, such as malignancies. The recognition of these risk factors has sparked interest in regimens that limit exposure to CNIs. Nowadays, the use of immunosuppressive drugs with different mechanisms of action, which allow for a reduction or avoidance of CNIs, is common. Everolimus, which belongs to the mammalian target-of-rapamycin inhibitor family and is best known for its use in kidney and heart transplantation, has recently been approved for liver transplantation. This overview discusses the emerging evidence on the role of everolimus in the prevention of rejection after liver transplantation, in de novo transplants, conversion regimens, or as a rescue therapy. In addition, some of the most relevant and current clinical problems related to everolimus in this field are discussed. Keywords: everolimus, mTOR inhibitors, tacrolimus, liver transplant, cyclosporine, renal impairment

Intranasal Cotinine Plus Krill Oil Facilitates Fear Extinction, Decreases Depressive-Like Behavior, and Increases Hippocampal Calcineurin A Levels in Mice.

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Alvarez-Ricartes, Nathalie; Oliveros-Matus, Patricia; Mendoza, Cristhian; Perez-Urrutia, Nelson; Echeverria, Florencia; Iarkov, Alexandre; Barreto, George E; Echeverria, Valentina

2018-02-27

Failure in fear extinction is one of the more troublesome characteristics of posttraumatic stress disorder (PTSD). Cotinine facilitates fear memory extinction and reduces depressive-like behavior when administered 24 h after fear conditioning in mice. In this study, it was investigated the behavioral and molecular effects of cotinine, and other antidepressant preparations infused intranasally. Intranasal (IN) cotinine, IN krill oil, IN cotinine plus krill oil, and oral sertraline were evaluated on depressive-like behavior and fear retention and extinction after fear conditioning in C57BL/6 mice. Since calcineurin A has been involved in facilitating fear extinction in rodents, we also investigated changes of calcineurin in the hippocampus, a region key on contextual fear extinction. Short-term treatment with cotinine formulations was superior to krill oil and oral sertraline in reducing depressive-like behavior and fear consolidation and enhancing contextual fear memory extinction in mice. IN krill oil slowed the extinction of fear. IN cotinine preparations increased the levels of calcineurin A in the hippocampus of conditioned mice. In the light of the results, the future investigation of the use of IN cotinine preparations for the extinction of contextual fear memory and treatment of treatment-resistant depression (TRD) in PTSD is discussed.

The effect of C1-esterase inhibitor in definite and suspected streptococcal toxic shock syndrome. Report of seven patients.

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Fronhoffs, S; Luyken, J; Steuer, K; Hansis, M; Vetter, H; Walger, P

2000-10-01

To evaluate the effect of adjunctive C1-esterase inhibitor substitution therapy on clinical characteristics and outcome of patients with streptococcal toxic shock syndrome (TSS). Observational. Medizinische Poliklinik, University of Bonn, Germany. Seven patients with direct or indirect evidence of streptococcal TSS. In addition to conventional and supportive therapy, all patients received 2-3 single doses of C1-esterase inhibitor totaling 6,000-10,000 U within the first 24 h after admission. All patients developed fulminant septic shock, multiorgan failure and/or capillary leak syndrome and necrotizing fasciitis within 10-72 h following the onset of first symptoms. Between 1 and 4 days following administration of C1-esterase inhibitor, a marked shift of fluid from extravascular to intravascular compartments took place in all but one patient, accompanied by a transient intra-alveolar lung edema and rapidly decreasing need for adrenergic agents. Six of seven patients survived. These clinical observations in a small series of patients and the favorable outcome point towards a positive effect of early and high-dose administration of C1-esterase inhibitor as adjunctive therapy in streptococcal TSS. The possible mechanism involved may be the attenuation of capillary leak syndrome (CLS) via early inactivation of complement and contact systems. Controlled studies are needed to establish an improvement of the survival rates of patients with streptococcal TSS following administration of C1-esterase inhibitor.

Endothelial Regulator of Calcineurin 1 Promotes Barrier Integrity and Modulates Histamine-Induced Barrier Dysfunction in Anaphylaxis

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Constanza Ballesteros-Martinez

2017-10-01

Full Text Available Anaphylaxis, the most serious and life-threatening allergic reaction, produces the release of inflammatory mediators by mast cells and basophils. Regulator of calcineurin 1 (Rcan1 is a negative regulator of mast-cell degranulation. The action of mediators leads to vasodilation and an increase in vascular permeability, causing great loss of intravascular volume in a short time. Nevertheless, the molecular basis remains unexplored on the vascular level. We investigated Rcan1 expression induced by histamine, platelet-activating factor (PAF, and epinephrine in primary human vein (HV-/artery (HA-derived endothelial cells (ECs and human dermal microvascular ECs (HMVEC-D. Vascular permeability was analyzed in vitro in human ECs with forced Rcan1 expression using Transwell migration assays and in vivo using Rcan1 knockout mice. Histamine, but neither PAF nor epinephrine, induced Rcan1-4 mRNA and protein expression in primary HV-ECs, HA-ECs, and HMVEC-D through histamine receptor 1 (H1R. These effects were prevented by pharmacological inhibition of calcineurin with cyclosporine A. Moreover, intravenous histamine administration increased Rcan1 expression in lung tissues of mice undergoing experimental anaphylaxis. Functional in vitro assays showed that overexpression of Rcan1 promotes barrier integrity, suggesting a role played by this molecule in vascular permeability. Consistent with these findings, in vivo models of subcutaneous and intravenous histamine-mediated fluid extravasation showed increased response in skin, aorta, and lungs of Rcan1-deficient mice compared with wild-type animals. These findings reveal that endothelial Rcan1 is synthesized in response to histamine through a calcineurin-sensitive pathway and may reduce barrier breakdown, thus contributing to the strengthening of the endothelium and resistance to anaphylaxis. These new insights underscore its potential role as a regulator of sensitivity to anaphylaxis in humans.

Subchronic Toxicities of HZ1006, a Hydroxamate-Based Histone Deacetylase Inhibitor, in Beagle Dogs and Sprague-Dawley Rats

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Xiaofang Zhang

2016-11-01

Full Text Available Histone deacetylase inhibitors (HDACIs, such as vorinostat and panobinostat, have been shown to have active effects on many hematologic malignancies, including multiple myeloma and cutaneous T-cell lymphoma. Hydroxamate-based (Hb HDACIs have very good toxicity profiles and are currently being tested in phases I and II clinical trials with promising results in selected neoplasms, such as bladder carcinoma. One of the Hb-HDACIs, HZ1006, has been demonstrated to be a promising drug for clinical use. The aim of our study was to determine the possible target of toxicity and to identify a non-toxic dose of HZ1006 for clinical use. In our studies, the repeated dosage toxicity of HZ1006 in Beagle dogs and Sprague Dawley (SD rats was identified. Dogs and rats received HZ1006 orally (0–80 and 0–120 mg/kg/day, respectively on a continuous daily dosing agenda for 28 days following a 14-day dosage-free period. HZ1006’s NOAEL (No Observed Adverse Effect Level by daily oral administration for dogs and rats was 5 mg/kg and 60 mg/kg, respectively, and the minimum toxic dose was 20 and 120 mg/kg, respectively. All the side effects indicated that the digestive tract, the male reproductive tract, the respiratory tract and the hematological systems might be HZ1006 toxic targets in humans. HZ1006 could be a good candidate or a safe succedaneum to other existing HDACIs for the treatment of some solid tumor and hematologic malignancies.

Tumor necrosis factor alpha inhibitors in the treatment of toxic epidermal necrolysis.

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Woolridge, Katelyn F; Boler, Patrick L; Lee, Brian D

2018-01-01

Toxic epidermal necrolysis (TEN) is a rare, life-threatening adverse drug reaction for which there is no standardized or consistently effective treatment. Due to a greater understanding of disease pathogenesis and the identification of tumor necrosis factor (TNF) α as a mediator of keratinocyte death, TNF-α antagonists have been used in the treatment of TEN. Specifically, infliximab and etanercept have been shown to be effective at halting disease progression. The objective of this study is to review published case reports and case series using anti-TNF-α medications in the treatment of TEN. Results of many of the articles reviewed support the use of TNF-α inhibitors in TEN in both adult and pediatric populations; however, the risks caused by these potent immunosuppressants must be weighed, and if administered, patients must be closely monitored for infections. Additional studies are needed to further characterize the role of TNF-α inhibition in the treatment of TEN.

The mTOR inhibitor sirolimus suppresses renal, hepatic, and cardiac tissue cellular respiration.

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Albawardi, Alia; Almarzooqi, Saeeda; Saraswathiamma, Dhanya; Abdul-Kader, Hidaya Mohammed; Souid, Abdul-Kader; Alfazari, Ali S

2015-01-01

The purpose of this in vitro study was to develop a useful biomarker (e.g., cellular respiration, or mitochondrial O2 consumption) for measuring activities of mTOR inhibitors. It measured the effects of commonly used immunosuppressants (sirolimus-rapamycin, tacrolimus, and cyclosporine) on cellular respiration in target tissues (kidney, liver, and heart) from C57BL/6 mice. The mammalian target of rapamycin (mTOR), a serine/ threonine kinase that supports nutrient-dependent cell growth and survival, is known to control energy conversion processes within the mitochondria. Consistently, inhibitors of mTOR (e.g., rapamycin, also known as sirolimus or Rapamune®) have been shown to impair mitochondrial function. Inhibitors of the calcium-dependent serine/threonine phosphatase calcineurin (e.g., tacrolimus and cyclosporine), on the other hand, strictly prevent lymphokine production leading to a reduced T-cell function. Sirolimus (10 μM) inhibited renal (22%, P=0.002), hepatic (39%, Prespiration. Tacrolimus and cyclosporine had no or minimum effects on cellular respiration in these tissues. Thus, these results clearly demonstrate that impaired cellular respiration (bioenergetics) is a sensitive biomarker of the immunosuppressants that target mTOR.

Promising Diabetes Therapy Based on the Molecular Mechanism for Glucose Toxicity: Usefulness of SGLT2 Inhibitors as well as Incretin-Related Drugs.

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Kaneto, Hideaki; Obata, Atsushi; Shimoda, Masashi; Kimura, Tomohiko; Hirukawa, Hidenori; Okauchi, Seizo; Matsuoka, Taka-Aki; Kaku, Kohei

2016-01-01

Pancreatic β-cell dysfunction and insulin resistance are the main characteristics of type 2 diabetes. Chronic exposure of β-cells to hyperglycemia leads to the deterioration of β-cell function. Such phenomena are well known as pancreatic β-cell glucose toxicity. MafA, a strong transactivator of insulin gene, is particularly important for the maintenance of mature β-cell function, but its expression level is significantly reduced under diabetic conditions which is likely associated with β-cell failure. Reduction of incretin receptor expression level in β-cells in diabetes is also likely associated with β-cell failure. On the other hand, incretin-related drugs and sodium-glucose co-transporter 2 (SGLT2) inhibitors are promising diabetes therapy based on the mechanism for pancreatic β-cell glucose toxicity. Indeed, it was shown that incretin-related drugs exerted protective effects on β-cells through the augmentation of IRS-2 expression especially in the presence of pioglitazone. It was also shown that incretin-related drug and/or pioglitazone exerted more protective effects on β-cells at the early stage of diabetes compared to the advanced stage. SGLT2 inhibitors, new hypoglycemic agents, also exert beneficial effects for the protection of pancreatic β-cells as well as for the reduction of insulin resistance in various insulin target tissues. Taken together, it is important to select appropriate therapy based on the molecular mechanism for glucose toxicity.

Crystallization and preliminary crystallographic analysis of a calcineurin B-like protein 1 (CBL1) mutant from Ammopiptanthus mongolicus

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Shang, Guijun; Cang, Huaixing; Liu, Zhijie; Gao, Wei; Bi, Ruchang

2010-01-01

Recombinant calcineurin B-like protein 1 from Ammopiptanthus mongolicus (AmCBL1) was overexpressed, purified and crystallized. Calcineurin B-like protein 1 (CBL1) is a calcium sensor in plants. It transmits the calcium signal through the downstream protein CBL-interacting protein kinase (CIPK). CBL1 and CIPK play crucial roles in the response to environmental stresses such as low K + , osmotic shock, high salt, cold and drought. Recombinant CBL1 from Ammopiptanthus mongolicus (AmCBL1) was overexpressed, purified and crystallized. However, the crystal did not diffract well. A mutant prepared using the surface-entropy method and crystallized using the hanging-drop method at 298 K with PEG 2000 MME as a precipitant diffracted to 2.90 Å resolution. The crystal belonged to space group P2 1 2 1 2, with unit-cell parameters a = 99.87, b = 114.42, c = 63.80 Å, α = β = γ = 90.00° and three molecules per asymmetric unit

Nebula/DSCR1 upregulation delays neurodegeneration and protects against APP-induced axonal transport defects by restoring calcineurin and GSK-3β signaling.

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Shaw, Jillian L; Chang, Karen T

2013-01-01

Post-mortem brains from Down syndrome (DS) and Alzheimer's disease (AD) patients show an upregulation of the Down syndrome critical region 1 protein (DSCR1), but its contribution to AD is not known. To gain insights into the role of DSCR1 in AD, we explored the functional interaction between DSCR1 and the amyloid precursor protein (APP), which is known to cause AD when duplicated or upregulated in DS. We find that the Drosophila homolog of DSCR1, Nebula, delays neurodegeneration and ameliorates axonal transport defects caused by APP overexpression. Live-imaging reveals that Nebula facilitates the transport of synaptic proteins and mitochondria affected by APP upregulation. Furthermore, we show that Nebula upregulation protects against axonal transport defects by restoring calcineurin and GSK-3β signaling altered by APP overexpression, thereby preserving cargo-motor interactions. As impaired transport of essential organelles caused by APP perturbation is thought to be an underlying cause of synaptic failure and neurodegeneration in AD, our findings imply that correcting calcineurin and GSK-3β signaling can prevent APP-induced pathologies. Our data further suggest that upregulation of Nebula/DSCR1 is neuroprotective in the presence of APP upregulation and provides evidence for calcineurin inhibition as a novel target for therapeutic intervention in preventing axonal transport impairments associated with AD.

Functional interpretation of metabolomics data as a new method for predicting long-term side effects: treatment of atopic dermatitis in infants.

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Lee, Seul Ji; Woo, Sung-il; Ahn, Soo Hyun; Lim, Dong Kyu; Hong, Ji Yeon; Park, Jeong Hill; Lim, Johan; Kim, Mi-kyeong; Kwon, Sung Won

2014-12-10

Topical steroids are used for the treatment of primary atopic dermatitis (AD); however, their associated risk of serious complications is great due to the presence of vulnerable lesions in young children with AD. Topical calcineurin inhibitors (TCIs) are steroid-free, anti-inflammatory agents used for topical AD therapy. However, their use is prohibited in infants side effects. The 1% pimecrolimus cream displayed similar efficacy and exceptional safety compared with the 0.05% desonide cream. Metabolomics-based long-term toxicity tests effectively predicted long-term side effects using short-term clinical models. This applicable method for the functional interpretation of metabolomics data sets the foundation for future studies involving the prediction of the toxicity and systemic reactions caused by long-term medication administration.

Acute lymphoid and gastrointestinal toxicity induced by selective p38alpha map kinase and map kinase-activated protein kinase-2 (MK2) inhibitors in the dog.

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Morris, Dale L; O'Neil, Shawn P; Devraj, Rajesh V; Portanova, Joseph P; Gilles, Richard W; Gross, Cindy J; Curtiss, Sandra W; Komocsar, Wendy J; Garner, Debra S; Happa, Fernando A; Kraus, Lori J; Nikula, Kristen J; Monahan, Joseph B; Selness, Shaun R; Galluppi, Gerald R; Shevlin, Kimberly M; Kramer, Jeffrey A; Walker, John K; Messing, Dean M; Anderson, David R; Mourey, Robert J; Whiteley, Laurence O; Daniels, John S; Yang, Jerry Z; Rowlands, Philip C; Alden, Carl L; Davis, John W; Sagartz, John E

2010-06-01

Exposure to moderately selective p38alpha mitogen-activated protein kinase (MAPK) inhibitors in the Beagle dog results in an acute toxicity consisting of mild clinical signs (decreased activity, diarrhea, and fever), lymphoid necrosis and depletion in the gut-associated lymphoid tissue (GALT), mesenteric lymph nodes and spleen, and linear colonic and cecal mucosal hemorrhages. Lymphocyte apoptosis and necrosis in the GALT is the earliest and most prominent histopathologic change observed, followed temporally by neutrophilic infiltration and acute inflammation of the lymph nodes and spleen and multifocal mucosal epithelial necrosis and linear hemorrhages in the colon and cecum. These effects are not observed in the mouse, rat, or cynomolgus monkey. To further characterize the acute toxicity in the dog, a series of in vivo, in vitro, and immunohistochemical studies were conducted to determine the relationship between the lymphoid and gastrointestinal (GI) toxicity and p38 MAPK inhibition. Results of these studies demonstrate a direct correlation between p38alpha MAPK inhibition and the acute lymphoid and gastrointestinal toxicity in the dog. Similar effects were observed following exposure to inhibitors of MAPK-activated protein kinase-2 (MK2), further implicating the role of p38alpha MAPK signaling pathway inhibition in these effects. Based on these findings, the authors conclude that p38alpha MAPK inhibition results in acute lymphoid and GI toxicity in the dog and is unique among the species evaluated in these studies.

Effect of a new functional CYP3A4 polymorphism on calcineurin inhibitors' dose requirements and trough blood levels in stable renal transplant patients.

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Elens, Laure; van Schaik, Ron H; Panin, Nadtha; de Meyer, Martine; Wallemacq, Pierre; Lison, Dominique; Mourad, Michel; Haufroid, Vincent

2011-10-01

CYP3A4 is involved in the oxidative metabolism of many drugs and xenobiotics including the immunosuppressants tacrolimus (Tac) and cyclosporine (CsA). The objective of the study was to assess the potential influence of a new functional SNP in CYP3A4 on the pharmacokinetic parameters assessed by dose requirements and trough blood levels of both calcineurin inhibitors (CNI) in stable renal transplant patients. A total of 99 stable renal transplant patients receiving either Tac (n = 49) or CsA (n = 50) were genotyped for the CYP3A4 intron 6 C>T (rs35599367) and CYP3A5*3 SNPs. Trough blood levels ([Tac](0) or [CsA](0) in ng/ml), dose-adjusted [Tac](0) or [CsA](0) (ng/ml per mg/kg bodyweight) as well as doses (mg/kg bodyweight) required to achieve target concentrations were compared among patients according to allelic status for CYP3A4 and CYP3A5. Dose-adjusted concentrations were 2.0- and 1.6-fold higher in T-variant allele carriers for the CYP3A4 intron 6 C>T SNP compared with homozygous CC for Tac and CsA, respectively. When CYP3A4/CYP3A5 genotypes were combined, the difference was even more striking as the so-defined CYP3A poor metabolizer group presented dose-adjusted concentration 1.6- and 4.1-fold higher for Tac, and 1.5- and 2.2-fold higher for CsA than the intermediate metabolizer and extensive metabolizer groups, respectively. Multiple linear regression analysis revealed that, taken together, both CYP3A4 intron 6 and CYP3A5*3 SNPs explained more than 60 and 20% of the variability observed in dose-adjusted [Tac](0) and [CsA](0), respectively. The CYP3A4 intron 6 C>T polymorphism is associated with altered Tac and CsA metabolism. CYP3A4 intron 6 C>T along with CYP3A5*3 (especially for Tac) pharmacogenetic testing performed just before transplantation may help identifying patients at risk of CNI overexposure and contribute to limit CNI-related nephrotoxicity by refining the starting dose according to their genotype. Original submitted 5 May 2011; Revision

VEGF selectively induces Down syndrome critical region 1 gene expression in endothelial cells: a mechanism for feedback regulation of angiogenesis?

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Yao, Y.-G; Duh, Elia J.

2004-01-01

The Down syndrome critical region 1 (DSCR1) gene (also known as MCIP1, Adapt78) encodes a regulatory protein that binds to calcineurin catalytic A subunit and acts as a regulator of the calcineurin-mediated signaling pathway. We show in this study that DSCR1 is greatly induced in endothelial cells in response to VEGF, TNF-α, and A23187 treatment, and that this up-regulation is inhibited by inhibitors of the calcineurin-NFAT (nuclear factor of activated T cells) signaling pathway as well as by PKC inhibition and a Ca 2+ chelator. We hypothesized that the up-regulation of DSCR1 gene expression in endothelial cells could act as an endogenous feedback inhibitor for angiogenesis by regulating the calcineurin-NFAT signaling pathway. Our transient transfection analyses confirm that the overexpression of DSCR1 abrogates the up-regulation of reporter gene expression driven by both the cyclooxygenase 2 and DSCR1 promoters in response to stimulators. Our results indicate that DSCR1 up-regulation may represent a potential molecular mechanism underlying the regulation of angiogenic genes activated by the calcineurin-NFAT signaling pathway in endothelial cells

Cyclosporin A inhibits nucleotide excision repair via downregulation of the xeroderma pigmentosum group A and G proteins, which is mediated by calcineurin inhibition.

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Kuschal, Christiane; Thoms, Kai-Martin; Boeckmann, Lars; Laspe, Petra; Apel, Antje; Schön, Michael P; Emmert, Steffen

2011-10-01

Cyclosporin A (CsA) inhibits nucleotide excision repair (NER) in human cells, a process that contributes to the skin cancer proneness in organ transplant patients. We investigated the mechanisms of CsA-induced NER reduction by assessing all xeroderma pigmentosum (XP) genes (XPA-XPG). Western blot analyses revealed that XPA and XPG protein expression was reduced in normal human GM00637 fibroblasts exposed to 0.1 and 0.5 μm CsA. Interestingly, the CsA treatment reduced XPG, but not XPA, mRNA expression. Calcineurin knockdown in GM00637 fibroblasts using RNAi led to similar results suggesting that calcineurin-dependent signalling is involved in XPA and XPG protein regulation. CsA-induced reduction in NER could be complemented by the overexpression of either XPA or XPG protein. Likewise, XPA-deficient fibroblasts with stable overexpression of XPA (XP2OS-pCAH19WS) did not show the inhibitory effect of CsA on NER. In contrast, XPC-deficient fibroblasts overexpressing XPC showed CsA-reduced NER. Our data indicate that the CsA-induced inhibition of NER is a result of downregulation of XPA and XPG protein in a calcineurin-dependent manner. © 2011 John Wiley & Sons A/S.

The cathepsin B inhibitor, z-FA-CMK is toxic and readily induced cell death in human T lymphocytes

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Liow, K.Y.; Chow, S.C., E-mail: chow.sek.chuen@monash.edu

2013-11-01

The cathepsin B inhibitor, benzyloxycarbonyl-phenylalanine-alanine-chloromethylketone (z-FA-CMK) was found to be toxic and readily induced cell death in the human T cell line, Jurkat, whereas two other analogs benzyloxycarbonyl-phenylalanine-alanine-fluoromethylketone (z-FA-FMK) and benzyloxycarbonyl-phenylalanine-alanine-diazomethylketone (z-FA-DMK) were not toxic. The toxicity of z-FA-CMK requires not only the CMK group, but also the presence of alanine in the P1 position and the benzyloxycarbonyl group at the N-terminal. Dose–response studies showed that lower concentrations of z-FA-CMK induced apoptosis in Jurkat T cells whereas higher concentrations induced necrosis. In z-FA-CMK-induced apoptosis, both initiator caspases (-8 and -9) and effector caspases (-3, -6 and -7) were processed to their respective subunits in Jurkat T cells. However, only the pro-form of the initiator caspases were reduced in z-FA-CMK-induced necrosis and no respective subunits were apparent. The caspase inihibitor benzyloxycarbonyl-valine-alanine-aspartic acid-(O-methyl)-fluoromehylketone (z-VAD-FMK) inhibits apoptosis and caspase processing in Jurkat T cells treated with low concentration of z-FA-CMK but has no effect on z-FA-CMK-induced necrosis and the loss of initiator caspases. This suggests that the loss of initiator caspases in Jurkat T cells during z-FA-CMK-induced necrosis is not a caspase-dependent process. Taken together, we have demonstrated that z-FA-CMK is toxic to Jurkat T cells and induces apoptosis at low concentrations, while at higher concentrations the cells die of necrosis. - Highlights: • z-FA-CMK is toxic and induce cell death in the human T cells. • z-FA-CMK toxicity requires the CMK group, alanine and the benzyloxycarbonyl group. • z-FA-CMK induced apoptosis at low concentration and necrosis at high concentration.

The cathepsin B inhibitor, z-FA-CMK is toxic and readily induced cell death in human T lymphocytes

International Nuclear Information System (INIS)

Liow, K.Y.; Chow, S.C.

2013-01-01

The cathepsin B inhibitor, benzyloxycarbonyl-phenylalanine-alanine-chloromethylketone (z-FA-CMK) was found to be toxic and readily induced cell death in the human T cell line, Jurkat, whereas two other analogs benzyloxycarbonyl-phenylalanine-alanine-fluoromethylketone (z-FA-FMK) and benzyloxycarbonyl-phenylalanine-alanine-diazomethylketone (z-FA-DMK) were not toxic. The toxicity of z-FA-CMK requires not only the CMK group, but also the presence of alanine in the P1 position and the benzyloxycarbonyl group at the N-terminal. Dose–response studies showed that lower concentrations of z-FA-CMK induced apoptosis in Jurkat T cells whereas higher concentrations induced necrosis. In z-FA-CMK-induced apoptosis, both initiator caspases (-8 and -9) and effector caspases (-3, -6 and -7) were processed to their respective subunits in Jurkat T cells. However, only the pro-form of the initiator caspases were reduced in z-FA-CMK-induced necrosis and no respective subunits were apparent. The caspase inihibitor benzyloxycarbonyl-valine-alanine-aspartic acid-(O-methyl)-fluoromehylketone (z-VAD-FMK) inhibits apoptosis and caspase processing in Jurkat T cells treated with low concentration of z-FA-CMK but has no effect on z-FA-CMK-induced necrosis and the loss of initiator caspases. This suggests that the loss of initiator caspases in Jurkat T cells during z-FA-CMK-induced necrosis is not a caspase-dependent process. Taken together, we have demonstrated that z-FA-CMK is toxic to Jurkat T cells and induces apoptosis at low concentrations, while at higher concentrations the cells die of necrosis. - Highlights: • z-FA-CMK is toxic and induce cell death in the human T cells. • z-FA-CMK toxicity requires the CMK group, alanine and the benzyloxycarbonyl group. • z-FA-CMK induced apoptosis at low concentration and necrosis at high concentration

Nebula/DSCR1 upregulation delays neurodegeneration and protects against APP-induced axonal transport defects by restoring calcineurin and GSK-3β signaling.

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Jillian L Shaw

Full Text Available Post-mortem brains from Down syndrome (DS and Alzheimer's disease (AD patients show an upregulation of the Down syndrome critical region 1 protein (DSCR1, but its contribution to AD is not known. To gain insights into the role of DSCR1 in AD, we explored the functional interaction between DSCR1 and the amyloid precursor protein (APP, which is known to cause AD when duplicated or upregulated in DS. We find that the Drosophila homolog of DSCR1, Nebula, delays neurodegeneration and ameliorates axonal transport defects caused by APP overexpression. Live-imaging reveals that Nebula facilitates the transport of synaptic proteins and mitochondria affected by APP upregulation. Furthermore, we show that Nebula upregulation protects against axonal transport defects by restoring calcineurin and GSK-3β signaling altered by APP overexpression, thereby preserving cargo-motor interactions. As impaired transport of essential organelles caused by APP perturbation is thought to be an underlying cause of synaptic failure and neurodegeneration in AD, our findings imply that correcting calcineurin and GSK-3β signaling can prevent APP-induced pathologies. Our data further suggest that upregulation of Nebula/DSCR1 is neuroprotective in the presence of APP upregulation and provides evidence for calcineurin inhibition as a novel target for therapeutic intervention in preventing axonal transport impairments associated with AD.

Clinical use of PI3K inhibitors in B-cell lymphoid malignancies: today and tomorrow.

Science.gov (United States)

Greenwell, I B; Flowers, C R; Blum, K A; Cohen, J B

2017-03-01

PI3K inhibitors are an important new therapeutic option for the treatment of relapsed and refractory B-cell lymphoid malignancies. Idelalisib is a PI3Kδ inhibitor that has been approved for the treatment of lymphoma and chronic lymphocytic leukemia in the relapsed/refractory setting, and several other PI3K inhibitors are being developed targeting other isoforms of the PI3K enzyme, which results in distinct toxicities and variable efficacy in the clinical setting. Areas covered: We provide a general overview of PI3K inhibitors, recommended applications, and the mechanism and management of toxicities. We further review trials, ongoing and completed, leading to the approval of idelalisib as well other PI3K inhibitors currently in development. Articles were obtained from PubMed, and abstracts were searched for the past 5 years from the websites for ASCO, ASH, EHA, and ICML/Lugano. Expert commentary: PI3K inhibitors provide an important and powerful pharmacologic tool in the armamentarium against hematologic malignancies, especially for relapsed/refractory B-cell lymphoid malignancies. Unique toxicities are associated with inhibition of different isoforms of the PI3K enzyme, as demonstrated with the infectious and autoimmune toxicities associated with the PI3Kδ inhibitor, idelalisib. Due to these unique toxicities, PI3K inhibitors should only be used in formally approved combinations and settings.

Lysophospholipase inhibition by organophosphorus toxicants

International Nuclear Information System (INIS)

Quistad, Gary B.; Casida, John E.

2004-01-01

Lysophospholipases (LysoPLAs) are a large family of enzymes for removing lysophospholipids from cell membranes. Potent inhibitors are needed to define the importance of LysoPLAs as targets for toxicants and potential therapeutics. This study considers organophosphorus (OP) inhibitors with emphasis on mouse brain total LysoPLA activity relative to the mipafox-sensitive neuropathy target esterase (NTE)-LysoPLA recently established as 17% of the total activity and important in the action of OP delayed toxicants. The most potent inhibitors of total LysoPLA in mouse brain are isopropyl dodecylphosphonofluoridate (also for LysoPLA of Vibrio bacteria), ethyl octylphosphonofluoridate (EOPF), and two alkyl-benzodioxaphosphorin 2-oxides (BDPOs)[(S)-octyl and dodecyl] (IC50 2-8 nM). OP inhibitors acting in vitro and in vivo differentiate a more sensitive portion but not a distinct NTE-LysoPLA compared with total LysoPLA activity. For 10 active inhibitors, NTE-LysoPLA is 17-fold more sensitive than total LysoPLA, but structure-activity comparisons give a good correlation (r 2 = 0.94) of IC50 values, suggesting active site structural similarity or identity. In mice 4 h after intraperitoneal treatment with discriminating doses, EOPF, tribufos (a plant defoliant), and dodecanesulfonyl fluoride inhibit 41-57% of the total brain LysoPLA and 85-99% of the NTE-LysoPLA activity. Total LysoPLA as well as NTE-LysoPLA is decreased in activity in Nte +/- -haploinsufficient mice compared to their Nte +/+ littermates. The lysolecithin level of spinal cord but not brain is elevated significantly following EOPF treatment (3 mg/kg), thereby focusing attention on localized rather than general alterations in lysophospholipid metabolism in OP-induced hyperactivity and toxicity

Renal-sparing strategies in cardiac transplantation

DEFF Research Database (Denmark)

Gustafsson, Finn; Ross, Heather J

2009-01-01

PURPOSE OF REVIEW: Renal dysfunction due to calcineurin inhibitor (CNI) toxicity is a major clinical problem in cardiac transplantation. The aim of the article is to review the efficacy and safety of various renal sparing strategies in cardiac transplantation. RECENT FINDINGS: Small studies have...... reduction in terms of preserving renal function. Patients with longstanding CNI treatment or proteinuria are less likely to respond favourably to a switch from a CNI-based regimen to a proliferation signal inhibitor-based regimen. SUMMARY: Each cardiac transplant recipient with renal dysfunction must...... documented that late initiation of CNI is safe in patients treated with induction therapy at the time of transplantation. Use of mycophenolate is superior when compared with azathioprine to allow for CNI reduction. More substantial reduction in CNI levels is safe and effective with the introduction...

Role of the Ca2+-Calcineurin-Nuclear Factor of Activated T cell Pathway in Mitofusin-2-Mediated Immune Function of Jurkat Cells

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Xiu-Ping Xu

2018-01-01

Conclusions: Our findings suggest that MFN2 may regulate T cell immune functions primarily through the Ca2+-calcineurin-NFAT pathway. MFN2 may represent a potential therapeutic target for T cell immune dysfunction-related diseases.

Peptide inhibitors of botulinum neurotoxin by mRNA display

International Nuclear Information System (INIS)

Yiadom, Kwabena P.A.B.; Muhie, Seid; Yang, David C.H.

2005-01-01

Botulinum neurotoxins (BoNTs) are extremely toxic. The metalloproteases associated with the toxins cleave proteins essential for neurotransmitter secretion. Inhibitors of the metalloprotease are currently sought to control the toxicity of BoNTs. Toward that goal, we produced a synthetic cDNA for the expression and purification of the metalloprotease of BoNT/A in Escherichia coli as a biotin-ubiquitin fusion protein, and constructed a combinatorial peptide library to screen for BoNT/A light chain inhibitors using mRNA display. A protease assay was developed using immobilized intact SNAP-25 as the substrate. The new peptide inhibitors showed a 10-fold increase in affinity to BoNT/A light chain than the parent peptide. Interestingly, the sequences of the new peptide inhibitors showed abundant hydrophobic residues but few hydrophilic residues. The results suggest that mRNA display may provide a general approach in developing peptide inhibitors of BoNTs

Milk fermentation products of L. helveticus R389 activate calcineurin as a signal to promote gut mucosal immunity

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Perdigón Gabriela

2007-09-01

Full Text Available Background Fermented milks containing probiotic bacteria are a way of delivering bioactive constituents to targets in the gastrointestinal tract. We reported previously that the fermentation of milk at constant pH 6 by L. helveticus R389 increased its content of peptide fractions, and the oral administration of the non-bacterial fraction (FMSpH6 to mice increased total secretory IgA in the intestinal lumen and enhanced the number of IgA and various cytokines producing cells as well as the secretion of IL-6 by small intestine epithelial cells. We also demonstrated that this FMSpH6 was effective for the prevention of Salmonella typhimurium infection in mice. In this work, we studied in mice the impact of the oral administration of the supernatant of milk fermented by L. helveticus R389 on the gut physiology by measuring parameters such as calcium channels and E-cadherin expression, the activation of the biological signal calcineurin and mast and goblet cells, as a way to determine some mechanisms involved in the immunomodulating effects of the milk fermentation products, observed in previous studies. We analyzed the impact of the supernatant of milk fermented by L. helveticus R389 at pH6-controlled on the expression of calcineurin and on the reinforcement of the ephitelial barrier, measuring parameters such as calcium channels and E-cadherin expression and in the reinforcement of the non-specific immunity determining mast cells and goblet cells associated to the gut. Results We observed an enhanced expression of TRPV6 channels in the duodenum, indicating an improved capacity for dietary Ca2+ uptake. We demonstrated an enhanced expression of calcineurin in the small intestine, able to upregulate immune parameters such as IL-2 and TNF production, with an increase in the number of these cytokines secreting cells. We determined an increase in the number of mucosal mast cells and goblet cells, which would mean an improved state of mucosal surveillance

BCR SIGNALING INHIBITORS: AN OVERVIEW OF TOXICITIES ASSOCIATED WITH IBRUTINIB AND IDELALISIB IN PATIENTS WITH CHRONIC LYMPHOCYTIC LEUKEMIA

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Lorenzo Falchi

2016-02-01

Full Text Available The B-cell receptor signaling inhibitors ibrutinib and idelalisib are revolutionizing the treatment landscape of chronic lymphocytic leukemia (CLL and other B-cell malignancies. These oral agents, both alone and in combination with other drugs, have shown remarkable clinical activity in relapsed or refractory CLL across all risk groups, and have been approved by the Food and Drug Administration for this indication. Preliminary data suggest that an even greater benefit can be expected in treatment-naïve CLL patients. Both ibrutinib and idelalisib are well tolerated by most patients, including older, frailer individuals. Toxicities are usually mild and self-resolving. Clinicians must, however, be aware of a number of peculiar adverse events, the effects of which can be severe enough to limit the clinical use of these agents. In this review, we survey the salient aspects of the pharmacology of these agents, as well as clinical experience regarding their use for the treatment of patients with CLL. Our foci will be both the most common and the most clinically significant toxicities associated with these drugs.

The SARS-coronavirus-host interactome: identification of cyclophilins as target for pan-coronavirus inhibitors.

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Susanne Pfefferle

2011-10-01

Full Text Available Coronaviruses (CoVs are important human and animal pathogens that induce fatal respiratory, gastrointestinal and neurological disease. The outbreak of the severe acute respiratory syndrome (SARS in 2002/2003 has demonstrated human vulnerability to (Coronavirus CoV epidemics. Neither vaccines nor therapeutics are available against human and animal CoVs. Knowledge of host cell proteins that take part in pivotal virus-host interactions could define broad-spectrum antiviral targets. In this study, we used a systems biology approach employing a genome-wide yeast-two hybrid interaction screen to identify immunopilins (PPIA, PPIB, PPIH, PPIG, FKBP1A, FKBP1B as interaction partners of the CoV non-structural protein 1 (Nsp1. These molecules modulate the Calcineurin/NFAT pathway that plays an important role in immune cell activation. Overexpression of NSP1 and infection with live SARS-CoV strongly increased signalling through the Calcineurin/NFAT pathway and enhanced the induction of interleukin 2, compatible with late-stage immunopathogenicity and long-term cytokine dysregulation as observed in severe SARS cases. Conversely, inhibition of cyclophilins by cyclosporine A (CspA blocked the replication of CoVs of all genera, including SARS-CoV, human CoV-229E and -NL-63, feline CoV, as well as avian infectious bronchitis virus. Non-immunosuppressive derivatives of CspA might serve as broad-range CoV inhibitors applicable against emerging CoVs as well as ubiquitous pathogens of humans and livestock.

Sirolimus-associated interstitial pneumonitis in a liver transplant recipient

International Nuclear Information System (INIS)

Claire Berrouet, Marie; Aristizabal, Julian Miguel; Restrepo, Juan Carlos; Correa, Gonzalo

2005-01-01

Sirolimus is an immunosuppressive drug that has been used during the past few years. Sirolimus is indicated in rescue therapies and to reduce the secondary toxic effects of calcineurin inhibitors. This drug has been associated with infrequent but severe pulmonary toxicity. Cases of interstitial pneumonitis, bronchiolitis obliterans with organizing pneumonia, and alveolar proteinosis have been described. We describe a case of pulmonary toxicity associated with the use of sirolimus in a 59-yr-old liver transplant recipient. We also review all reported cases of sirolimus-associated lung toxicity among liver transplantation recipients, with the intention of understanding the risk factors, the clinical picture and the outcomes of this complication. Five cases have been reported since January 2000, including the present case. Clinical presentation is similar, with fever, dyspnoea, fatigue, cough, and hemoptysis. Discontinuation of the drug led to resolution of clinical and radiographic findings. Sirolimus-induced pulmonary toxicity is a serious condition and should be considered in the differential diagnosis of liver recipients presenting with respiratory findings. Discontinuation of the drug is associated with resolution of the pulmonary compromise

Imaging of hepatic toxicity of systemic therapy in a tertiary cancer centre: chemotherapy, haematopoietic stem cell transplantation, molecular targeted therapies, and immune checkpoint inhibitors.

Science.gov (United States)

Alessandrino, F; Tirumani, S H; Krajewski, K M; Shinagare, A B; Jagannathan, J P; Ramaiya, N H; Di Salvo, D N

2017-07-01

The purpose of this review is to familiarise radiologists with the spectrum of hepatic toxicity seen in the oncology setting, in view of the different systemic therapies used in cancer patients. Drug-induced liver injury can manifest in various forms, and anti-neoplastic agents are associated with different types of hepatotoxicity. Although chemotherapy-induced liver injury can present as hepatitis, steatosis, sinusoidal obstruction syndrome, and chronic parenchymal damages, molecular targeted therapy-associated liver toxicity ranges from mild liver function test elevation to fulminant life-threatening acute liver failure. The recent arrival of immune checkpoint inhibitors in oncology has introduced a new range of immune-related adverse events, with differing mechanisms of liver toxicity and varied imaging presentation of liver injury. High-dose chemotherapy regimens for haematopoietic stem cell transplantation are associated with sinusoidal obstruction syndrome. Management of hepatic toxicity depends on the clinical scenario, the drug in use, and the severity of the findings. In this article, we will (1) present the most common types of oncological drugs associated with hepatic toxicity and associated liver injuries; (2) illustrate imaging findings of hepatic toxicities and the possible differential diagnosis; and (3) provide a guide for management of these conditions. Copyright © 2017 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Serotonin Toxicity Caused by Moclobemide Too Soon After Paroxetine-Selegiline

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Ming-Ling Wu

2009-08-01

Full Text Available Serotonin toxicity is an iatrogenic complication of serotonergic drug therapy. It is due to an overstimulation of central and peripheral serotonin receptors that lead to neuromuscular, mental and autonomic changes. Moclobemide is a reversible inhibitor of monoamine oxidase (MAO-A, selegiline is an irreversible selective inhibitor of MAO-B, and paroxetine is a selective serotonin reuptake inhibitor. Combined use of these agents is known to cause serotonin toxicity. A 53-year-old woman had been treated with paroxetine and selegiline. After moclobemide was prescribed in place of paroxetine without a washout period, she quickly developed confusion, agitation, ataxia, diaphoresis, tremor, mydriasis, ocular clonus, hyper-reflexia, tachycardia, moderately elevated blood pressure and high fever, symptoms that were consistent with serotonin toxicity. Discontinuation of the drugs, hydration and supportive care were followed by remarkable improvement of baseline status within 3 days. This case demonstrates that serotonin toxicity may occur even with small doses of paroxetine, selegi-line and moclobemide in combination. Physicians managing patients with depression must be aware of the potential for serotonin toxicity and should be able to recognize and treat or, ideally, anticipate and avoid this pharmacodynamically-mediated interaction that may occur between prescribed drugs.

Conversion from calcineurin inhibitors to sirolimus of recipients with chronic kidney graft disease grade iii for a period 2003-2011

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Ignjatović Ljiljana

2013-01-01

Full Text Available Background/Aim. Tremendous breakthrough in solid organ transplantation was made with the introduction of calcineurin inhibitors (CNI. At the same time, they are potentially nephrotoxic drugs with influence on onset and progression of renal graft failure. The aim of this study was to evaluate the outcome of a conversion from CNIbased immunosuppressive protocol to sirolimus (SRL in recipients with graft in chronic kidney disease (CKD grade III and proteinuria below 500 mg/day. Methods. In the period 2003-2011 24 patients (6 famale and 18 male, mean age 41 ± 12.2 years, on triple immunosuppressive therapy: steroids, antiproliferative drug [mycophenolate mofetil (MMF or azathiopirine (AZA] and CNI were switched from CNI to SRL and followe-up for 76 ± 13 months. Nine patients (the group I had early postransplant conversion after 4 ± 3 months and 15 patients (the group II late conversion after 46 ± 29 months. During the regular outpatient controls we followed graft function through the serum creatinine and glomerular filtration rate (GFR, proteinuria, lipidemia and side effects. Results. Thirty days after conversion, in all the patients GFR, proteinuria and lipidemia were insignificantly increased. In the first two post-conversion months all the patients had at least one urinary or respiratory infection, and 10 patients reactivated cytomegalovirus (CMV infection or disease, and they were successfully treated with standard therapy. After 21 ± 11 months 15 patients from both groups discontinued SRL therapy due to reconversion to CNI (10 patients and double immunosuppressive therapy (3 patients, return to hemodialysis (1 patient and death (1 patient. Nine patients were still on SRL therapy. By the end of the follow-up they significantly improved GFR (from 53.2 ± 12.7 to 69 ± 15 mL/min, while the increase in proteinuria (from 265 ± 239 to 530.6 ± 416.7 mg/day and lipidemia (cholesterol from 4.71 ± 0.98 to 5.61 ± 1.6 mmol/L and triglycerides

Role of metabolites and calcineurin inhibition on C2 monitoring in renal transplant patients

DEFF Research Database (Denmark)

Karamperis, N.; Koefoed-Nielsen, P.; Bagger, Sorensen A.

2005-01-01

BACKGROUND: Many transplantation centres have switched to C2 monitoring of cyclosporin-treated renal transplant patients. The rationale is that the C2 correlates best with AUC0-4 (area under the concentration-time curve), which again correlates with rejection and nephrotoxicity. It has also been...... metabolites were added to whole blood from healthy volunteers and the calcineurin phosphatase activity (CaN) was determined. Twenty renal transplant patients at varying times after transplantation had blood samples drawn in the morning before and 1, 2, 3 and 4 h after intake of their usual dose of cyclosporin...

Phytochemicals as Green Corrosion Inhibitors in Various Corrosive ...

African Journals Online (AJOL)

There is an intensive effort underway to develop new plant origin corrosion inhibitors for metal subjected to various environmental conditions. These efforts have been motivated by the desire to replace toxic inhibitors used for mitigation of corrosion of various metals and alloys in aqueous solutions. Plants represent a class ...

Discovery of a novel acyl-CoA: cholesterol acyltransferase inhibitor: the synthesis, biological evaluation, and reduced adrenal toxicity of (4-phenylcoumarin)acetanilide derivatives with a carboxylic acid moiety.

Science.gov (United States)

Ogino, Masaki; Nakada, Yoshihisa; Negoro, Nobuyuki; Itokawa, Shigekazu; Nishimura, Satoshi; Sanada, Tsukasa; Satomi, Tomoko; Kita, Shunbun; Kubo, Kazuki; Marui, Shogo

2011-01-01

As a part of our research for novel potent and orally available acyl-CoA: cholesterol acyltransferase (ACAT) inhibitors that can be used as anti-atherosclerotic agents, we recently reported the discovery of the (4-phenylcoumarine)acetanilide derivative 1. However, compound 1 showed adrenal toxicity in animal models. In order to search for safer ACAT inhibitors that do not have adrenal toxicity, we examined the inhibitory activity of ACAT in human macrophage and adrenal cells. The introduction of a carboxylic acid moiety on the pendant phenyl ring and the adjustment of the lipophilicity led to the discovery of (2E)-3-[7-chloro-3-[2-[[4-fluoro-2-(trifluoromethyl)phenyl]amino]-2-oxoethyl]-6-methyl-2-oxo-2H-chromen-4-yl]phenyl]acrylic acid (21e), which showed potent ACAT inhibitory activity in macrophages and a selectivity of around 30-fold over adrenal cells. In addition, compound 21e showed high adrenal safety in guinea pigs.

Arctigenin Inhibits Osteoclast Differentiation and Function by Suppressing Both Calcineurin-Dependent and Osteoblastic Cell-Dependent NFATc1 Pathways

OpenAIRE

Yamashita, Teruhito; Uehara, Shunsuke; Udagawa, Nobuyuki; Li, Feng; Kadota, Shigetoshi; Esumi, Hiroyasu; Kobayashi, Yasuhiro; Takahashi, Naoyuki

2014-01-01

Arctigenin, a lignan-derived compound, is a constituent of the seeds of Arctium lappa. Arctigenin was previously shown to inhibit osteoclastogenesis; however, this inhibitory mechanism has yet to be elucidated. Here, we showed that arctigenin inhibited the action of nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), a key transcription factor for osteoclastogenesis. NFATc1 in osteoclast precursors was activated through two distinct pathways: the calcineurin-dependent and osteoblasti...

EGFR-inhibitors, radiotherapy and normal tissue toxicity

DEFF Research Database (Denmark)

Eriksen, J. G.

2015-01-01

will be explained with references to the current knowledge of the biology of skin toxicity. Treatment options for acute side-effects in skin and mucosa after bio-radiotherapy is rarely causal. A few attempts have been done; some of them aiming to rephosphorylate the EGFreceptor in the skin with vitamin K3. The talk...

Molecular interaction of 2-mercaptobenzimidazole with catalase reveals a potentially toxic mechanism of the inhibitor.

Science.gov (United States)

Teng, Yue; Zou, Luyi; Huang, Ming; Zong, Wansong

2014-12-01

2-Mercaptobenzimidazole (MBI) is widely utilized as a corrosion inhibitor, copper-plating brightener and rubber accelerator. The residue of MBI in the environment possesses a potential risk to human health. In this work, the toxic interaction of MBI with the important antioxidant enzyme catalase (CAT) was investigated using spectroscopic and molecular docking methods under physiological conditions. MBI can spontaneously bind with CAT with one binding site through hydrogen bonds and van der Waals forces to form MBI-CAT complex. The molecular docking study revealed that MBI bound into the CAT interface of chains B and C, which led to some conformational and microenvironmental changes of CAT and further resulted in the inhibition of CAT activity. This present study provides direct evidence at a molecular level to show that exposure to MBI could induce changes in the structure and function of the enzyme CAT. Copyright © 2014 Elsevier B.V. All rights reserved.

A zebrafish model for uremic toxicity: role of the complement pathway.

Science.gov (United States)

Berman, Nathaniel; Lectura, Melisa; Thurman, Josh; Reinecke, James; Raff, Amanda C; Melamed, Michal L; Reinecke, James; Quan, Zhe; Evans, Todd; Meyer, Timothy W; Hostetter, Thomas H

2013-01-01

Many organic solutes accumulate in end-stage renal disease (ESRD) and some are poorly removed with urea-based prescriptions for hemodialysis. However, their toxicities have been difficult to assess. We have employed an animal model, the zebrafish embryo, to test the toxicity of uremic serum compared to control. Serum was obtained from stable ESRD patients predialysis or from normal subjects. Zebrafish embryos 24 h postfertilization were exposed to experimental media at a water:human serum ratio of 3:1. Those exposed to serum from uremic subjects had significantly reduced survival at 8 h (19 ± 18 vs. 94 ± 6%, p 50 kDa, respectively). Heating serum abrogated its toxicity. EDTA, a potent inhibitor of complement by virtue of calcium chelation, reduced the toxicity of uremic serum compared to untreated uremic serum (96 ± 5 vs. 28 ± 20% survival, p < 0.016, chelated vs. nonchelated serum, respectively). Anti-factor B, a specific inhibitor of the alternative complement pathway, reduced the toxicity of uremic serum, compared to untreated uremic serum (98 ± 6 vs. 3 ± 9% survival, p < 0.016, anti-factor B treated vs. nontreated, respectively). Uremic serum is thus more toxic to zebrafish embryos than normal serum. Furthermore, this toxicity is associated with a fraction of large size, is inactivated by heat, and is reduced by both specific and nonspecific inhibitors of complement activation. Together these data lend support to the hypothesis that at least some uremic toxicities may be mediated by complement. Copyright © 2013 S. Karger AG, Basel.

Metabolism of citral, the major constituent of lemongrass oil, in the cabbage looper, Trichoplusia ni, and effects of enzyme inhibitors on toxicity and metabolism.

Science.gov (United States)

Tak, Jun-Hyung; Isman, Murray B

2016-10-01

Although screening for new and reliable sources of botanical insecticides remains important, finding ways to improve the efficacy of those already in use through better understanding of their modes-of-action or metabolic pathways, or by improving formulations, deserves greater attention as the latter may present lesser regulation hurdles. Metabolic processing of citral (a combination of the stereoisomers geranial and neral), a main constituent of lemongrass (Cymbopogon citratus) essential oil has not been previously examined in insects. To address this, we investigated insecticidal activities of lemongrass oil and citral, as well as the metabolism of citral in larvae of the cabbage looper, Trichoplusia ni, in associations with well-known enzyme inhibitors. Among the inhibitors tested, piperonyl butoxide showed the highest increase in toxicity followed by triphenyl phosphate, but no synergistic interaction between the inhibitors was observed. Topical application of citral to fifth instar larvae produced mild reductions in food consumption, and frass analysis after 24h revealed geranic acid (99.7%) and neric acid (98.8%) as major metabolites of citral. Neither citral nor any other metabolites were found following in vivo analysis of larvae after 24h, and no significant effect of enzyme inhibitors was observed on diet consumption or citral metabolism. Copyright © 2016 Elsevier B.V. All rights reserved.

Toxicity of Neatex (industrial detergent) and Norust CR 486 ...

African Journals Online (AJOL)

Populations of indigenous epigeic adult earthworms, Aporrectodea longa, were exposed to varying concentrations of two chemicals (industrial detergent and corrosion inhibitor) in natural soil to determine the acute toxicity of the chemicals. Earthworm acute toxicity test (OECD) 207 method was employed. After two weeks of ...

Nutritional intervention restores muscle but not kidney phenotypes in adult calcineurin Aα null mice.

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Kirsten Madsen

Full Text Available Mice lacking the α isoform of the catalytic subunit of calcineurin (CnAα were first reported in 1996 and have been an important model to understand the role of calcineurin in the brain, immune system, bones, muscle, and kidney. Research using the mice has been limited, however, by failure to thrive and early lethality of most null pups. Work in our laboratory led to the rescue of CnAα-/- mice by supplemental feeding to compensate for a defect in salivary enzyme secretion. The data revealed that, without intervention, knockout mice suffer from severe caloric restriction. Since nutritional deprivation is known to significantly alter development, it is imperative that previous conclusions based on CnAα-/- mice are revisited to determine which aspects of the phenotype were attributable to caloric restriction versus a direct role for CnAα. In this study, we find that defects in renal development and function persist in adult CnAα-/- mice including a significant decrease in glomerular filtration rate and an increase in blood urea nitrogen levels. These data indicate that impaired renal development we previously reported was not due to caloric restriction but rather a specific role for CnAα in renal development and function. In contrast, we find that rather than being hypoglycemic, rescued mice are mildly hyperglycemic and insulin resistant. Examination of muscle fiber types shows that previously reported reductions in type I muscle fibers are no longer evident in rescued null mice. Rather, loss of CnAα likely alters insulin response due to a reduction in insulin receptor substrate-2 (IRS2 expression and signaling in muscle. This study illustrates the importance of re-examining the phenotypes of CnAα-/- mice and the advances that are now possible with the use of adult, rescued knockout animals.

Effect of trifluoperazine on toxicity, HIF-1α induction and hepatocyte regeneration in acetaminophen toxicity in mice

Energy Technology Data Exchange (ETDEWEB)

Chaudhuri, Shubhra, E-mail: SCHAUDHURI@uams.edu [Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas (United States); Arkansas Children' s Hospital Research Institute, Little Rock, AR (United States); McCullough, Sandra S., E-mail: mcculloughsandras@uams.edu [Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas (United States); Arkansas Children' s Hospital Research Institute, Little Rock, AR (United States); Hennings, Leah, E-mail: lhennings@uams.edu [Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, Arkansas (United States); Arkansas Children' s Hospital Research Institute, Little Rock, AR (United States); Brown, Aliza T., E-mail: brownalizat@uams.edu [Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas (United States); Arkansas Children' s Hospital Research Institute, Little Rock, AR (United States); Li, Shun-Hwa [Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI (United States); Simpson, Pippa M., E-mail: psimpson@mcw.edu [Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI (United States); Hinson, Jack A., E-mail: hinsonjacka@uams.edu [Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, Arkansas Children' s Hospital Research Institute, Little Rock, AR (United States); James, Laura P., E-mail: jameslaurap@uams.edu [Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas (United States); Arkansas Children' s Hospital Research Institute, Little Rock, AR (United States); Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, Arkansas Children' s Hospital Research Institute, Little Rock, AR (United States)

2012-10-15

Oxidative stress and mitochondrial permeability transition (MPT) are important mechanisms in acetaminophen (APAP) toxicity. The MPT inhibitor trifluoperazine (TFP) reduced MPT, oxidative stress, and toxicity in freshly isolated hepatocytes treated with APAP. Since hypoxia inducible factor-one alpha (HIF-1α) is induced very early in APAP toxicity, a role for oxidative stress in the induction has been postulated. In the present study, the effect of TFP on toxicity and HIF-1α induction in B6C3F1 male mice treated with APAP was examined. Mice received TFP (10 mg/kg, oral gavage) prior to APAP (200 mg/kg IP) and at 7 and 36 h after APAP. Measures of metabolism (hepatic glutathione and APAP protein adducts) were comparable in the two groups of mice. Toxicity was decreased in the APAP/TFP mice at 2, 4, and 8 h, compared to the APAP mice. At 24 and 48 h, there were no significant differences in toxicity between the two groups. TFP lowered HIF-1α induction but also reduced the expression of proliferating cell nuclear antigen, a marker of hepatocyte regeneration. TFP can also inhibit phospholipase A{sub 2}, and cytosolic and secretory PLA{sub 2} activity levels were reduced in the APAP/TFP mice compared to the APAP mice. TFP also lowered prostaglandin E{sub 2} expression, a known mechanism of cytoprotection. In summary, the MPT inhibitor TFP delayed the onset of toxicity and lowered HIF-1α induction in APAP treated mice. TFP also reduced PGE{sub 2} expression and hepatocyte regeneration, likely through a mechanism involving PLA{sub 2}. -- Highlights: ► Trifluoperazine reduced acetaminophen toxicity and lowered HIF-1α induction. ► Trifluoperazine had no effect on the metabolism of acetaminophen. ► Trifluoperazine reduced hepatocyte regeneration. ► Trifluoperazine reduced phospholipase A{sub 2} activity and prostaglandin E{sub 2} levels.

Calcineurin Aβ regulates NADPH oxidase (Nox) expression and activity via nuclear factor of activated T cells (NFAT) in response to high glucose.

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Williams, Clintoria R; Gooch, Jennifer L

2014-02-21

Hypertrophy is an adaptive response that enables organs to appropriately meet increased functional demands. Previously, we reported that calcineurin (Cn) is required for glomerular and whole kidney hypertrophy in diabetic rodents (Gooch, J. L., Barnes, J. L., Garcia, S., and Abboud, H. E. (2003). Calcineurin is activated in diabetes and is required for glomerular hypertrophy and ECM accumulation. Am. J. Physiol. Renal Physiol. 284, F144-F154; Reddy, R. N., Knotts, T. L., Roberts, B. R., Molkentin, J. D., Price, S. R., and Gooch, J. L. (2011). Calcineurin Aβ is required for hypertrophy but not matrix expansion in the diabetic kidney. J. Cell Mol. Med. 15, 414-422). Because studies have also implicated the reactive oxygen species-generating enzymes NADPH oxidases (Nox) in diabetic kidney responses, we tested the hypothesis that Nox and Cn cooperate in a common signaling pathway. First, we examined the role of the two main isoforms of Cn in hypertrophic signaling. Using primary kidney cells lacking a catalytic subunit of Cn (CnAα(-/-) or CnAβ(-/-)), we found that high glucose selectively activates CnAβ, whereas CnAα is constitutively active. Furthermore, CnAβ but not CnAα mediates hypertrophy. Next, we found that chronic reactive oxygen species generation in response to high glucose is attenuated in CnAβ(-/-) cells, suggesting that Cn is upstream of Nox. Consistent with this, loss of CnAβ reduces basal expression and blocks high glucose induction of Nox2 and Nox4. Inhibition of nuclear factor of activated T cells (NFAT), a CnAβ-regulated transcription factor, decreases Nox2 and Nox4 expression, whereas NFAT overexpression increases Nox2 and Nox4, indicating that the CnAβ/NFAT pathway modulates Nox. These data reveal that the CnAβ/NFAT pathway regulates Nox and plays an important role in high glucose-mediated hypertrophic responses in the kidney.

Regulator of calcineurin 1 differentially regulates TLR-dependent MyD88 and TRIF signaling pathways.

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Zheng Pang

Full Text Available Toll-like receptors (TLRs recognize the conserved molecular patterns in microorganisms and trigger myeloid differentiation primary response 88 (MyD88 and/or TIR-domain-containing adapter-inducing interferon-β (TRIF pathways that are critical for host defense against microbial infection. However, the molecular mechanisms that govern TLR signaling remain incompletely understood. Regulator of calcineurin-1 (RCAN1, a small evolutionarily conserved protein that inhibits calcineurin phosphatase activity, suppresses inflammation during Pseudomonas aeruginosa infection. Here, we define the roles for RCAN1 in P. aeruginosa lipopolysaccharide (LPS-activated TLR4 signaling. We compared the effects of P. aeruginosa LPS challenge on bone marrow-derived macrophages from both wild-type and RCAN1-deficient mice and found that RCAN1 deficiency increased the MyD88-NF-κB-mediated cytokine production (IL-6, TNF and MIP-2, whereas TRIF-interferon-stimulated response elements (ISRE-mediated cytokine production (IFNβ, RANTES and IP-10 was suppressed. RCAN1 deficiency caused increased IκBα phosphorylation and NF-κB activity in the MyD88-dependent pathway, but impaired ISRE activation and reduced IRF7 expression in the TRIF-dependent pathway. Complementary studies of a mouse model of P. aeruginosa LPS-induced acute pneumonia confirmed that RCAN1-deficient mice displayed greatly enhanced NF-κB activity and MyD88-NF-κB-mediated cytokine production, which correlated with enhanced pulmonary infiltration of neutrophils. By contrast, RCAN1 deficiency had little effect on the TRIF pathway in vivo. These findings demonstrate a novel regulatory role of RCAN1 in TLR signaling, which differentially regulates MyD88 and TRIF pathways.

SEARCH OF NEW SYNTHETIC INHIBITORS OF TYROSINASE

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Yu. Shesterenko

2017-11-01

Full Text Available Melanin pigmentation of skin plays the most important role in the protection of organism against UV-irradiation, but the excessive accumulation of melanin brings to toxic melanodermia, melasma, lentigo and other skin lesions. Tyrosinase is the key enzyme of skin melanin pigment biosynthesis. In spite of certain progress in investigation of natural and synthetic tyrosinase inhibitors, actuality of such studies is of a high level, because the existing inhibitors are in some cases unstable, expensive, toxic, requires complex methods of synthesis or isolation from natural sources. The aim of the work is screening of new tyrosinase inhibitors, using the enzyme, isolated from Agaricus bisporus. Tyrosinase was isolated from Agaricus bisporus mushrooms by a modified method. It was found, that the introduction of polyethylene glycol 4000 in the extraction process promotes 3-fold reduction of polyphenol content, which leads to increase purity of enzyme with an increase in its activity by 25%. A search for new tyrosinase inhibitors among a wide range of compounds, including derivatives of 3-chloro-1,4-naphthoquinone, isatin, 3-hydroxy-2-naphthoic acid, etc was conducted. The studied substances did not displayed inhibitory effect at concentration of 0,1-0,5 mmol/dm3.

Neurologic Complications of Transplantation.

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Dhar, Rajat

2018-02-01

Neurologic disturbances including encephalopathy, seizures, and focal deficits complicate the course 10-30% of patients undergoing organ or stem cell transplantation. While much or this morbidity is multifactorial and often associated with extra-cerebral dysfunction (e.g., graft dysfunction, metabolic derangements), immunosuppressive drugs also contribute significantly. This can either be through direct toxicity (e.g., posterior reversible encephalopathy syndrome from calcineurin inhibitors such as tacrolimus in the acute postoperative period) or by facilitating opportunistic infections in the months after transplantation. Other neurologic syndromes such as akinetic mutism and osmotic demyelination may also occur. While much of this neurologic dysfunction may be reversible if related to metabolic factors or drug toxicity (and the etiology is recognized and reversed), cases of multifocal cerebral infarction, hemorrhage, or infection may have poor outcomes. As transplant patients survive longer, delayed infections (such as progressive multifocal leukoencephalopathy) and post-transplant malignancies are increasingly reported.

Role of heterotrimeric G protein and calcium in cardiomyocyte hypertrophy induced by IGF-1.

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Carrasco, Loreto; Cea, Paola; Rocco, Paola; Peña-Oyarzún, Daniel; Rivera-Mejias, Pablo; Sotomayor-Flores, Cristian; Quiroga, Clara; Criollo, Alfredo; Ibarra, Cristian; Chiong, Mario; Lavandero, Sergio

2014-04-01

In the heart, insulin-like growth factor-1 (IGF-1) is a peptide with pro-hypertrophic and anti-apoptotic actions. The pro-hypertrophic properties of IGF-1 have been attributed to the extracellular regulated kinase (ERK) pathway. Recently, we reported that IGF-1 also increases intracellular Ca(2+) levels through a pertussis toxin (PTX)-sensitive G protein. Here we investigate whether this Ca(2+) signal is involved in IGF-1-induced cardiomyocyte hypertrophy. Our results show that the IGF-1-induced increase in Ca(2+) level is abolished by the IGF-1 receptor tyrosine kinase inhibitor AG538, PTX and the peptide inhibitor of Gβγ signaling, βARKct. Increases in the activities of Ca(2+) -dependent enzymes calcineurin, calmodulin kinase II (CaMKII), and protein kinase Cα (PKCα) were observed at 5 min after IGF-1 exposure. AG538, PTX, βARKct, and the dominant negative PKCα prevented the IGF-1-dependent phosphorylation of ERK1/2. Participation of calcineurin and CaMKII in ERK phosphorylation was discounted. IGF-1-induced cardiomyocyte hypertrophy, determined by cell size and β-myosin heavy chain (β-MHC), was prevented by AG538, PTX, βARKct, dominant negative PKCα, and the MEK1/2 inhibitor PD98059. Inhibition of calcineurin with CAIN did not abolish IGF-1-induced cardiac hypertrophy. We conclude that IGF-1 induces hypertrophy in cultured cardiomyocytes by activation of the receptor tyrosine kinase activity/βγ-subunits of a PTX-sensitive G protein/Ca(2+) /PKCα/ERK pathway without the participation of calcineurin. © 2013 Wiley Periodicals, Inc.

Exploring BSEP Inhibition-Mediated Toxicity with a Mechanistic Model of Drug-Induced Liver Injury

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Jeffrey L Woodhead

2014-11-01

Full Text Available Inhibition of the bile salt export pump (BSEP has been linked to incidence of drug-induced liver injury (DILI, presumably by the accumulation of toxic bile acids in the liver. We have previously constructed and validated a model of bile acid disposition within DILIsym®, a mechanistic model of DILI. In this paper, we use DILIsym® to simulate the DILI response of the hepatotoxic BSEP inhibitors bosentan and CP-724,714 and the non-hepatotoxic BSEP inhibitor telmisartan in humans in order to explore whether we can predict that hepatotoxic BSEP inhibitors can cause bile acid accumulation to reach toxic levels. We also simulate bosentan in rats in order to illuminate potential reasons behind the lack of toxicity in rats compared to the toxicity observed in humans. DILIsym® predicts that bosentan, but not telmisartan, will cause mild hepatocellular ATP decline and serum ALT elevation in a simulated population of humans. The difference in hepatotoxic potential between bosentan and telmisartan is consistent with clinical observations. However, DILIsym® underpredicts the incidence of bosentan toxicity. DILIsym® also predicts that bosentan will not cause toxicity in a simulated population of rats, and that the difference between the response to bosentan in rats and in humans is primarily due to the less toxic bile acid pool in rats. Our simulations also suggest a potential synergistic role for bile acid accumulation and mitochondrial electron transport chain inhibition in producing the observed toxicity in CP-724,714, and suggest that CP-724,714 metabolites may also play a role in the observed toxicity. Our work also compares the impact of competitive and noncompetitive BSEP inhibition for CP-724,714 and demonstrates that noncompetitive inhibition leads to much greater bile acid accumulation and potential toxicity. Our research demonstrates the potential for mechanistic modeling to contribute to the understanding of how bile acid transport inhibitors

Localized palmar-plantar epidermal hyperplasia: a previously undefined dermatologic toxicity to sorafenib.

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Beldner, Matthew; Jacobson, Michael; Burges, Gene E; Dewaay, Deborah; Maize, John C; Chaudhary, Uzair B

2007-10-01

The development of multitargeted tyrosine kinase inhibitors has provided significant advances in the treatment of renal cell carcinoma. This case describes initial therapy for managing renal cell cancer with the administration of sorafenib, a multitargeted tyrosine kinase inhibitor. We report the development of localized palmar-plantar epidermal hyperplasia, a rare but significant cutaneous adverse event from sorafenib therapy. Mild-to-moderate dermatologic toxicity from sorafenib has been well described in the literature. We also review the current knowledge and the proposed hypothesis for the development of cutaneous events related to tyrosine kinase inhibitors. This particular case represents a unique form of dermatologic toxicity to sorafenib that has not previously been described in the literature.

Effect of cyclosporine, tacrolimus and sirolimus on cellular senescence in renal epithelial cells.

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Koppelstaetter, Christian; Kern, Georg; Leierer, Gisela; Mair, Sabine Maria; Mayer, Gert; Leierer, Johannes

2018-04-01

In transplantation medicine calcineurin inhibitors (CNI) still represent the backbone of immunosuppressive therapy. The nephrotoxic potential of the CNI Cyclosporine A (CsA) and Tacrolimus (FK506) is well recognized and CNI not only have been linked with toxicity, but also with cellular senescence which hinders parenchymal tissue regeneration and thus may prime kidneys for subsequent insults. To minimize pathological effects on kidney grafts, alternative immunosuppressive agents like mTOR inhibitors or the T-cell co-stimulation blocker Belatacept have been introduced. We compared the effects of CsA, FK506 and Sirolimus on the process of cellular senescence in different human renal tubule cell types (HK2, RPTEC). Telomere length (by real time PCR), DNA synthesis (by BrdU incorporation), cell viability (by Resazurin conversion), gene expression (by RT-PCR), protein (by western blotting), Immuncytochemistry and H 2 O 2 production (by Amplex Red® conversion) were evaluated. DNA synthesis was significantly reduced when cells were treated with cyclosporine but not with tacrolimus and sirolimus. Resazurin conversion was not altered by all three immunosuppressive agents. The gene expression as well as protein production of the cell cycle inhibitor p21 (CDKN1A) but not p16 (CDKN2A) was significantly induced by cyclosporine compared to the other two immunosuppressive agents when determined by western blotting an immuncytochemistry. Relative telomere length was reduced and hydrogen peroxide production increased after treatment with CsA but not with FK506 or sirolimus. In summary, renal tubule cells exposed to CsA show clear signs of cellular senescence where on the contrary the second calcineurin inhibitor FK506 and the mTOR inhibitor sirolimus are not involved in such mechanisms. Chronic renal allograft dysfunction could be in part triggered by cellular senescence induced by immunosuppressive medication and the choice of drug could therefore influence long term outcome

A Limited Structural Modification Results in a Significantly More Efficacious Diazachrysene-Based Filovirus Inhibitor

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Rekha G. Panchal

2012-08-01

Full Text Available Ebola (EBOV and Marburg (MARV filoviruses are highly infectious pathogens causing deadly hemorrhagic fever in humans and non-human primates. Promising vaccine candidates providing immunity against filoviruses have been reported. However, the sporadic nature and swift progression of filovirus disease underlines the need for the development of small molecule therapeutics providing immediate antiviral effects. Herein we describe a brief structural exploration of two previously reported diazachrysene (DAAC-based EBOV inhibitors. Specifically, three analogs were prepared to examine how slight substituent modifications would affect inhibitory efficacy and inhibitor-mediated toxicity during not only EBOV, but also MARV cellular infection. Of the three analogs, one was highly efficacious, providing IC₅₀ values of 0.696 µM ± 0.13 µM and 2.76 µM ± 0.21 µM against EBOV and MARV infection, respectively, with little or no associated cellular toxicity. Overall, the structure-activity and structure-toxicity results from this study provide a framework for the future development of DAAC-based filovirus inhibitors that will be both active and non-toxic in vivo.

New synthetic thrombin inhibitors: molecular design and experimental verification.

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Elena I Sinauridze

Full Text Available BACKGROUND: The development of new anticoagulants is an important goal for the improvement of thromboses treatments. OBJECTIVES: The design, synthesis and experimental testing of new safe and effective small molecule direct thrombin inhibitors for intravenous administration. METHODS: Computer-aided molecular design of new thrombin inhibitors was performed using our original docking program SOL, which is based on the genetic algorithm of global energy minimization in the framework of a Merck Molecular Force Field. This program takes into account the effects of solvent. The designed molecules with the best scoring functions (calculated binding energies were synthesized and their thrombin inhibitory activity evaluated experimentally in vitro using a chromogenic substrate in a buffer system and using a thrombin generation test in isolated plasma and in vivo using the newly developed model of hemodilution-induced hypercoagulation in rats. The acute toxicities of the most promising new thrombin inhibitors were evaluated in mice, and their stabilities in aqueous solutions were measured. RESULTS: New compounds that are both effective direct thrombin inhibitors (the best K(I was 1111.1 mg/kg. A plasma-substituting solution supplemented with one of the new inhibitors prevented hypercoagulation in the rat model of hemodilution-induced hypercoagulation. Activities of the best new inhibitors in physiological saline (1 µM solutions were stable after sterilization by autoclaving, and the inhibitors remained stable at long-term storage over more than 1.5 years at room temperature and at 4°C. CONCLUSIONS: The high efficacy, stability and low acute toxicity reveal that the inhibitors that were developed may be promising for potential medical applications.

Drugs in development for prophylaxis of rejection in kidney-transplant recipients

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Sanders ML

2015-08-01

Full Text Available Marion Lee Sanders,1 Anthony James Langone2 1Department of Medicine, Division of Nephrology and Hypertension, University of Iowa, Iowa City, IA, 2Department of Medicine, Division of Nephrology and Hypertension, Vanderbilt University Medical Center, Nashville, TN, USA Abstract: Transplantation is the preferred treatment option for individuals with end-stage renal disease. Individuals who undergo transplantation must chronically be maintained on an immunosuppression regimen for rejection prophylaxis to help ensure graft survival. Current rejection prophylaxis consists of using a combination of calcineurin inhibitors, mTOR inhibitors, antimetabolite agents, and/or corticosteroids. These agents have collectively improved the short-term outcomes of renal transplantation, but improvements in late/chronic graft loss and recipient survival have lagged significantly behind challenging the field of transplantation to develop novel prophylactic agents. There have been several clinical trials conducted within the last 5 years in an attempt to bring such novel agents to the commercial market. These trials have resulted in the US Food and Drug Administration (FDA approval of extended-release tacrolimus, as well as belatacept, which has the potential to replace calcineurin inhibitors for rejection prophylaxis. Other trials have focused on the development of novel calcineurin inhibitors (voclosporin, costimulation blockade (ASKP1240 and alefacept, kinase inhibitors (tofacitinib and sotrastaurin, and inhibitors of leukocyte migration (efalizumab. While these later agents have not been FDA-approved for use in transplantation, they remain noteworthy, as these agents explore pathways not previously targeted for allograft-rejection prophylaxis. The purpose of this review was to consolidate available clinical trial data with regard to the recent developments in rejection prophylaxis in kidney transplantation. Keywords: rejection, prophylaxis, immunosuppression

New synthetic thrombin inhibitors: molecular design and experimental verification.

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Sinauridze, Elena I; Romanov, Alexey N; Gribkova, Irina V; Kondakova, Olga A; Surov, Stepan S; Gorbatenko, Aleksander S; Butylin, Andrey A; Monakov, Mikhail Yu; Bogolyubov, Alexey A; Kuznetsov, Yuryi V; Sulimov, Vladimir B; Ataullakhanov, Fazoyl I

2011-01-01

The development of new anticoagulants is an important goal for the improvement of thromboses treatments. The design, synthesis and experimental testing of new safe and effective small molecule direct thrombin inhibitors for intravenous administration. Computer-aided molecular design of new thrombin inhibitors was performed using our original docking program SOL, which is based on the genetic algorithm of global energy minimization in the framework of a Merck Molecular Force Field. This program takes into account the effects of solvent. The designed molecules with the best scoring functions (calculated binding energies) were synthesized and their thrombin inhibitory activity evaluated experimentally in vitro using a chromogenic substrate in a buffer system and using a thrombin generation test in isolated plasma and in vivo using the newly developed model of hemodilution-induced hypercoagulation in rats. The acute toxicities of the most promising new thrombin inhibitors were evaluated in mice, and their stabilities in aqueous solutions were measured. New compounds that are both effective direct thrombin inhibitors (the best K(I) was 50) in the thrombin generation assay of approximately 100 nM) were discovered. These compounds contain one of the following new residues as the basic fragment: isothiuronium, 4-aminopyridinium, or 2-aminothiazolinium. LD(50) values for the best new inhibitors ranged from 166.7 to >1111.1 mg/kg. A plasma-substituting solution supplemented with one of the new inhibitors prevented hypercoagulation in the rat model of hemodilution-induced hypercoagulation. Activities of the best new inhibitors in physiological saline (1 µM solutions) were stable after sterilization by autoclaving, and the inhibitors remained stable at long-term storage over more than 1.5 years at room temperature and at 4°C. The high efficacy, stability and low acute toxicity reveal that the inhibitors that were developed may be promising for potential medical applications.

Regulator of calcineurin 1 mediates pathological vascular wall remodeling

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Esteban, Vanesa; Méndez-Barbero, Nerea; Jesús Jiménez-Borreguero, Luis; Roqué, Mercè; Novensá, Laura; Belén García-Redondo, Ana; Salaices, Mercedes; Vila, Luis; Arbonés, María L.

2011-01-01

Artery wall remodeling, a major feature of diseases such as hypertension, restenosis, atherosclerosis, and aneurysm, involves changes in the tunica media mass that reduce or increase the vessel lumen. The identification of molecules involved in vessel remodeling could aid the development of improved treatments for these pathologies. Angiotensin II (AngII) is a key effector of aortic wall remodeling that contributes to aneurysm formation and restenosis through incompletely defined signaling pathways. We show that AngII induces vascular smooth muscle cell (VSMC) migration and vessel remodeling in mouse models of restenosis and aneurysm. These effects were prevented by pharmacological inhibition of calcineurin (CN) or lentiviral delivery of CN-inhibitory peptides. Whole-genome analysis revealed >1,500 AngII-regulated genes in VSMCs, with just 11 of them requiring CN activation. Of these, the most sensitive to CN activation was regulator of CN 1 (Rcan1). Rcan1 was strongly activated by AngII in vitro and in vivo and was required for AngII-induced VSMC migration. Remarkably, Rcan1−/− mice were resistant to AngII-induced aneurysm and restenosis. Our results indicate that aneurysm formation and restenosis share mechanistic elements and identify Rcan1 as a potential therapeutic target for prevention of aneurysm and restenosis progression. PMID:21930771

Opiate exposure state controls dopamine D3 receptor and cdk5/calcineurin signaling in the basolateral amygdala during reward and withdrawal aversion memory formation.

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Rosen, Laura G; Rushlow, Walter J; Laviolette, Steven R

2017-10-03

The dopamine (DA) D3 receptor (D3R) is highly expressed in the basolateral nucleus of the amygdala (BLA), a neural region critical for processing opiate-related reward and withdrawal aversion-related memories. Functionally, D3R transmission is linked to downstream Cdk5 and calcineurin signaling, both of which regulate D3R activity states and play critical roles in memory-related synaptic plasticity. Previous evidence links D3R transmission to opiate-related memory processing, however little is known regarding how chronic opiate exposure may alter D3R-dependent memory mechanisms. Using conditioned place preference (CPP) and withdrawal aversion (conditioned place aversion; CPA) procedures in rats, combined with molecular analyses of BLA protein expression, we examined the effects of chronic opiate exposure on the functional role of intra-BLA D3R transmission during the acquisition of opiate reward or withdrawal aversion memories. Remarkably, we report that the state of opiate exposure during behavioural conditioning (opiate-naïve/non-dependent vs. chronically exposed and in withdrawal) controlled the functional role of intra-BLA D3R transmission during the acquisition of both opiate reward memories and withdrawal-aversion associative memories. Thus, whereas intra-BLA D3R blockade had no effect on opiate reward memory formation in the non-dependent state, blockade of intra-BLA D3R transmission prevented the formation of opiate reward and withdrawal aversion memory in the chronically exposed state. This switch in the functional role of D3R transmission corresponded to significant increases in Cdk5 phosphorylation and total expression levels of calcineurin, and a corresponding decrease in intra-BLA D3R expression. Inhibition of either intra-BLA Cdk5 or calcineurin reversed these effects, switching intra-BLA associative memory formation back to a D3R-independent mechanism. Copyright © 2017 Elsevier Inc. All rights reserved.

Interplay between calcineurin and the Slt2 MAP-kinase in mediating cell wall integrity, conidiation and virulence in the insect fungal pathogen Beauveria bassiana.

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Huang, Shuaishuai; He, Zhangjiang; Zhang, Shiwei; Keyhani, Nemat O; Song, Yulin; Yang, Zhi; Jiang, Yahui; Zhang, Wenli; Pei, Yan; Zhang, Yongjun

2015-10-01

The entomopathogenic fungus, Beauveria bassiana, is of environmental and economic importance as an insect pathogen, currently used for the biological control of a number of pests. Cell wall integrity and conidiation are critical parameters for the ability of the fungus to infect insects and for production of the infectious propagules. The contribution of calcineurin and the Slt2 MAP kinase to cell wall integrity and development in B. bassiana was investigated. Gene knockouts of either the calcineurin CNA1 subunit or the Slt2 MAP kinase resulted in decreased tolerance to calcofluor white and high temperature. In contrast, the Δcna1 strain was more tolerant to Congo red but more sensitive to osmotic stress (NaCl, sorbitol) than the wild type, whereas the Δslt2 strain had the opposite phenotype. Changes in cell wall structure and composition were seen in the Δslt2 and Δcna1 strains during growth under cell wall stress as compared to the wild type. Both Δslt2 and Δcna1 strains showed significant alterations in growth, conidiation, and viability. Elevation of intracellular ROS levels, and decreased conidial hydrophobicity and adhesion to hydrophobic surfaces, were also seen for both mutants, as well as decreased virulence. Under cell wall stress conditions, inactivation of Slt2 significantly repressed CN-mediated phosphatase activity suggesting some level of cross talk between the two pathways. Comparative transcriptome profiling of the Δslt2 and Δcna1 strains revealed alterations in the expression of distinct gene sets, with overlap in transcripts involved in cell wall integrity, stress response, conidiation and virulence. These data illustrate convergent and divergent phenotypes and targets of the calcineurin and Slt2 pathways in B. bassiana. Copyright © 2015 Elsevier Inc. All rights reserved.

Evaluating the Toxicity of the Analgesic Glutaminase Inhibitor 6-Diazo-5-Oxo-L-Norleucine in vitro and on Rat Dermal Skin Fibroblasts

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Crosby, Heith A; Ihnat, Michael; Miller, Kenneth E

2018-01-01

6-diazo-5-oxo-l-norleucine (DON) is a glutamine antagonist produced naturally by Streptomyces. It inhibits several glutamine-dependent enzyme pathways. Of particular note is its inhibitory effect on the mitochondrial enzyme, glutaminase (GLS), the primary producer of neuronal glutamate. Glutamate is an excitatory neurotransmitter released by primary sensory peripheral nerve terminals and spinal synaptic terminals during pain signaling. Previous work using the tail incision and inflammatory models of pain has demonstrated that a single application of the glutaminase inhibitor, DON, into a surgical incision or the paw of arthritic animals results in pain relief. Even though this compound shows promise as a therapeutic agent, limited data exist regarding its dermal toxicity. As a first approach, we evaluated the effect of several concentrations of DON, on the viability, mitochondrial oxidative capacity and proliferation of rat skin fibroblasts, and then examined the effect of DON after incubation with human liver microsomes on proliferation. Finally, we evaluated DON treated rat skin (tail and hind paw) for cellular necrosis, inflammation and mitotic bodies. No significant effects (p > 0.05) of DON were noted on apoptosis, necrosis, and mitochondrial activity in experiments with cultured rat skin fibroblasts. Flow cytometry revealed the absence of apoptosis in cells treated at the IC50 of 232.5 μM. Enhanced toxicity post-exposure to human microsomes was not observed when compared to DON alone. The H&E staining of the rat skin revealed no obvious pathology in the DON treatment group (10 mM). DON has no/minimal cellular toxicity in vitro on dermal fibroblasts at concentrations that effectively provide analgesia. The local application of concentrations greater than the in vitro IC50 for DON revealed no in vivo skin toxicity. These data provide results indicating zero-to-minimal cellular toxicity with DON and support the further investigation of DON as an analgesic. PMID

MCPIP1 contributes to the toxicity of proteasome inhibitor MG-132 in HeLa cells by the inhibition of NF-κB.

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Skalniak, Lukasz; Dziendziel, Monika; Jura, Jolanta

2014-10-01

Recently, we have shown that the treatment of cells with proteasome inhibitor MG-132 results in the induction of expression of monocyte chemotactic protein-1 induced protein 1 (MCPIP1). MCPIP1 is a ribonuclease, responsible for the degradation of transcripts encoding certain pro-inflammatory cytokines. The protein is also known as an inhibitor of NF-κB transcription factor. Thanks to its molecular properties, MCPIP1 is considered as a regulator of inflammation, differentiation, and survival. Using siRNA technology, we show here that MCPIP1 expression contributes to the toxic properties of MG-132 in HeLa cells. The inhibition of proteasome by MG-132 and epoxomicin markedly increased MCPIP1 expression. While MG-132 induces HeLa cell death, down-regulation of MCPIP1 expression by siRNA partially protects HeLa cells from MG-132 toxicity and restores Nuclear factor-κB (NF-κB) activity, inhibited by MG-132 treatment. Inversely, overexpression of MCPIP1 decreased constitutive activity of NF-κB and limited the survival of HeLa cells, as we have shown in the previous study. Interestingly, although MG-132 decreased the expression of IκBα and increased p65 phosphorylation, the inhibition of constitutive NF-κB activity was observed in MG-132-treated cells. Since the elevated constitutive activity of NF-κB is one of the mechanisms providing increased survival of cancer cells, including HeLa cells, we propose that death-promoting properties of MCPIP1 in MG-132-treated HeLa cells may, at least partially, derive from the negative effect on the constitutive NF-κB activity.

Immunosuppression in the elderly renal allograft recipient

DEFF Research Database (Denmark)

Montero, Nuria; Pérez-Sáez, María José; Pascual, Julio

2016-01-01

BACKGROUND: The Elderly are the fastest growing part of kidney transplant recipients. The best immunosuppressive strategy is unknown. METHODS: We performed a systematic search of randomized controlled trials and observational studies focused on safety and efficacy of different immunosuppression...... strategies in elderly kidney recipients. Data extraction and risk of bias evaluation were systematically performed. RESULTS: Ten studies were included: 2 randomized clinical trials and 8 observational. A marginal benefit was found for early renal function with delayed tacrolimus or complete tacrolimus...... receptor antibody induction, calcineurin-inhibitor minimization with MMF and steroid minimization is advisable in the low immunologic risk elderly recipient, considering the increased risk of toxicities, infection and malignancies. In the high immunologic risk elderly recipient, taking into account...

Avoiding Severe Toxicity From Combined BRAF Inhibitor and Radiation Treatment: Consensus Guidelines from the Eastern Cooperative Oncology Group (ECOG)

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Anker, Christopher J., E-mail: chris.anker@UVMHealth.org [Division of Radiation Oncology, University of Vermont Cancer Center, Burlington, Vermont (United States); Grossmann, Kenneth F. [Division of Medical Oncology, Department of Medicine, Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah (United States); Atkins, Michael B. [Department of Oncology, Georgetown-Lombardi Comprehensive Cancer Center, Georgetown University School of Medicine, Washington, District of Columbia (United States); Suneja, Gita [Department of Radiation Oncology, Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah (United States); Tarhini, Ahmad A.; Kirkwood, John M. [Division of Hematology-Oncology, Department of Medicine, University of Pittsburgh Cancer Institute, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania (United States)

2016-06-01

BRAF kinase gene V600 point mutations drive approximately 40% to 50% of all melanomas, and BRAF inhibitors (BRAFi) have been found to significantly improve survival outcomes. Although radiation therapy (RT) provides effective symptom palliation, there is a lack of toxicity and efficacy data when RT is combined with BRAFi, including vemurafenib and dabrafenib. This literature review provides a detailed analysis of potential increased dermatologic, pulmonary, neurologic, hepatic, esophageal, and bowel toxicity from the combination of BRAFi and RT for melanoma patients described in 27 publications. Despite 7 publications noting potential intracranial neurotoxicity, the rates of radionecrosis and hemorrhage from whole brain RT (WBRT), stereotactic radiosurgery (SRS), or both do not appear increased with concurrent or sequential administration of BRAFis. Almost all grade 3 dermatitis reactions occurred when RT and BRAFi were administered concurrently. Painful, disfiguring nondermatitis cutaneous reactions have been described from concurrent or sequential RT and BRAFi administration, which improved with topical steroids and time. Visceral toxicity has been reported with RT and BRAFi, with deaths possibly related to bowel perforation and liver hemorrhage. Increased severity of radiation pneumonitis with BRAFi is rare, but more concerning was a potentially related fatal pulmonary hemorrhage. Conversely, encouraging reports have described patients with leptomeningeal spread and unresectable lymphadenopathy rendered disease free from combined RT and BRAFi. Based on our review, the authors recommend holding RT ≥3 days before and after fractionated RT and ≥1 day before and after SRS. No fatal reactions have been described with a dose <4 Gy per fraction, and time off systemic treatment should be minimized. Future prospective data will serve to refine these recommendations.

Pharmacogenetics and aromatase inhibitor induced side effects in breast cancer patients.

Science.gov (United States)

Sini, Valentina; Botticelli, Andrea; Lunardi, Gianluigi; Gori, Stefania; Marchetti, Paolo

2017-06-01

This paper reviews genetic variations mainly related to the onset of adverse events during aromatase inhibitors in early breast cancer. Genetic variability could occur at different steps. The analysis included studies that involved breast cancer patients, treated with an aromatase inhibitor, genotyped for CYP19A1 and/or CYP17A1 and/or CYP27B1 and/or TCLA1, and/or RANK/RANKL/OPG and/or ESR1/ESR2, and assessed for toxicity profile. Twenty-two articles were included for the analysis. Three studies evaluated outcomes and adverse events; 19 studies assessed only side effects. Functional variations may be useful in predicting the onset of toxicities. The identification of polymorphisms at increased risk of toxicity may enable patient management. However, more data are needed to be applied in the individualization of treatment in daily practice.

Cigarette smoke toxicants as substrates and inhibitors for human cytosolic SULTs

International Nuclear Information System (INIS)

Yasuda, Shin; Idell, Steven; Fu Jian; Carter, Glendora; Snow, Rhodora; Liu, M.-C.

2007-01-01

The current study was designed to examine the role of sulfation in the metabolism of cigarette smoke toxicants and clarify whether these toxicants, by serving as substrates for the cytosolic sulfotransferases (SULTs), may interfere with the sulfation of key endogenous compounds. By metabolic labeling, [ 35 S]sulfated species were found to be generated and released into the media of HepG2 human hepatoma cells and primary human lung endothelial cells labeled with [ 35 S]sulfate in the presence of cigarette smoke extract (CSE). Concomitantly, several [ 35 S]sulfated metabolites observed in the medium in the absence of CSE either decreased or disappeared. Eleven previously prepared human cytosolic SULTs were tested for sulfating activity with CSE and known cigarette smoke toxicants as substrates. Activity data revealed SULT1A1, SULT1A2, SULT1A3, and SULT1C2 as major enzymes responsible for their sulfation. To examine their inhibitory effects on the sulfation of 17β-estradiol by SULT1A1, enzymatic assays were performed in the presence of three representative toxicant compounds, namely N-hydroxy-4-aminobiphenyl (N-OH-4-ABP), 4-aminobiphenyl (4-ABP) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). IC 50 values determined for the sulfation of 17β-estradiol by SULT1A1 were 11.8 μM, 28.2 μM, and 500 μM, respectively, for N-OH-4-ABP, 4-ABP and PhIP. Kinetic analyses indicated that the mechanism underlying the inhibition of 17β-estradiol sulfation by these cigarette smoke toxicants is of a mixed competitive-noncompetitive type. Metabolic labeling experiments clearly showed inhibition of the production of [ 35 S]sulfated 17β-estradiol by N-OH-4-ABP in a concentration-dependent manner in HepG2 cells. Taken together, these results suggest that sulfation plays a significant role in the metabolism of cigarette smoke compounds. By serving as substrates for SULTs, cigarette smoke toxicants may interfere with the metabolism of 17β-estradiol and other endogenous

Nitric oxide donors prevent while the nitric oxide synthase inhibitor L-NAME increases arachidonic acid plus CYP2E1-dependent toxicity

International Nuclear Information System (INIS)

Wu Defeng; Cederbaum, Arthur

2006-01-01

Polyunsaturated fatty acids such as arachidonic acid (AA) play an important role in alcohol-induced liver injury. AA promotes toxicity in rat hepatocytes with high levels of cytochrome P4502E1 and in HepG2 E47 cells which express CYP2E1. Nitric oxide (NO) participates in the regulation of various cell activities as well as in cytotoxic events. NO may act as a protectant against cytotoxic stress or may enhance cytotoxicity when produced at elevated concentrations. The goal of the current study was to evaluate the effect of endogenously or exogenously produced NO on AA toxicity in liver cells with high expression of CYP2E1 and assess possible mechanisms for its actions. Pyrazole-induced rat hepatocytes or HepG2 cells expressing CYP2E1 were treated with AA in the presence or absence of an inhibitor of nitric oxide synthase L-N G -Nitroarginine Methylester (L-NAME) or the NO donors S-nitroso-N-acetylpenicillamine (SNAP), and (Z)-1-[-(2-aminoethyl)-N-(2-aminoethyl)]diazen-1-ium-1,2-diolate (DETA-NONO). AA decreased cell viability from 100% to 48 ± 6% after treatment for 48 h. In the presence of L-NAME, viability was further lowered to 23 ± 5%, while, SNAP or DETA-NONO increased viability to 66 ± 8 or 71 ± 6%. The L-NAME potentiated toxicity was primarily necrotic in nature. L-NAME did not affect CYP2E1 activity or CYP2E1 content. SNAP significantly lowered CYP2E1 activity but not protein. AA treatment increased lipid peroxidation and lowered GSH levels. L-NAME potentiated while SNAP prevented these changes. Thus, L-NAME increased, while NO donors decreased AA-induced oxidative stress. Antioxidants prevented the L-NAME potentiation of AA toxicity. Damage to mitochondria by AA was shown by a decline in the mitochondrial membrane potential (MMP). L-NAME potentiated this decline in MMP in association with its increase in AA-induced oxidative stress and toxicity. NO donors decreased this decline in MMP in association with their decrease in AA-induced oxidative stress and

Benzoylurea Chitin Synthesis Inhibitors.

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Sun, Ranfeng; Liu, Chunjuan; Zhang, Hao; Wang, Qingmin

2015-08-12

Benzoylurea chitin synthesis inhibitors are widely used in integrated pest management (IPM) and insecticide resistance management (IRM) programs due to their low toxicity to mammals and predatory insects. In the past decades, a large number of benzoylurea derivatives have been synthesized, and 15 benzoylurea chitin synthesis inhibitors have been commercialized. This review focuses on the history of commercial benzolyphenylureas (BPUs), synthetic methods, structure-activity relationships (SAR), action mechanism research, environmental behaviors, and ecotoxicology. Furthermore, their disadvantages of high risk to aquatic invertebrates and crustaceans are pointed out. Finally, we propose that the para-substituents at anilide of benzoylphenylureas should be the functional groups, and bipartite model BPU analogues are discussed in an attempt to provide new insight for future development of BPUs.

Current methods of the analysis of immunosuppressive agents in clinical materials: A review.

Science.gov (United States)

Mika, Adriana; Stepnowski, Piotr

2016-08-05

More than 100000 solid organ transplantations are performed every year worldwide. Calcineurin (cyclosporine A, tacrolimus), serine/threonine kinase (sirolimus, everolimus) and inosine monophosphate dehydrogenase inhibitor (mycophenolate mofetil), are the most common drugs used as immunosuppressive agents after solid organ transplantation. Immunosuppressive therapy, although necessary after transplantation, is associated with many adverse consequences, including the formation of secondary metabolites of drugs and the induction of their side effects. Calcineurin inhibitors are associated with nephrotoxicity, cardiotoxicity and neurotoxicity; moreover, they increase the risk of many diseases after transplantation. The review presents a study of the movement of drugs in the body, including the processes of absorption, distribution, localisation in tissues, biotransformation and excretion, and also their accompanying side effects. Therefore, there is a necessity to monitor immunosuppressants, especially because these drugs are characterised by narrow therapeutic ranges. Their incorrect concentrations in a patient's blood could result in transplant rejection or in the accumulation of toxic effects. Immunosuppressive pharmaceuticals are macrolide lactones, peptides, and high molecular weight molecules that can be metabolised to several metabolites. Therefore the two main analytical methods used for their determination are high performance liquid chromatography with various detection methods and immunoassay methods. Despite the rapid development of new analytical methods of analysing immunosuppressive agents, the application of the latest generation of detectors and increasing sensitivity of such methods, there is still a great demand for the development of highly selective, sensitive, specific, rapid and relatively simple methods of immunosuppressive drugs analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

Multiple signalling pathways redundantly control glucose transporter GLUT4 gene transcription in skeletal muscle

DEFF Research Database (Denmark)

Murgia, Marta; Elbenhardt Jensen, Thomas; Cusinato, Marzia

2009-01-01

on pharmacological evidence. Here, we have used a more specific genetic approach to establish the relative role of the three pathways in fast and slow muscles. Plasmids coding for protein inhibitors of CaMKII or calcineurin were co-transfected in vivo with a GLUT4 enhancer-reporter construct either in normal mice...... or in mice expressing a dominant negative AMPK mutant. GLUT4 reporter activity was not inhibited in the slow soleus muscle by blocking either CaMKII or calcineurin alone, but was inhibited by blocking both pathways. GLUT4 reporter activity was likewise unchanged in the soleus of dnAMPK mice......, but was significantly reduce by incapacitation of either CaMKII or calcineurin in these mice. On the other hand, in the fast tibialis anterior muscle, calcineurin appears to exert a prominent role in the control of GLUT4 reporter activity, independent of CaMKII and AMPK. The results point to a muscle type...

Epigenetic perturbations in the pathogenesis of mustard toxicity; hypothesis and preliminary results

International Nuclear Information System (INIS)

Korkmaz, A.; Yaren, H.; Kunak, I.; Uysal, B.; Kurt, B.; Topal, T.

2009-01-01

The pathogenesis of sulfur mustard (SM) toxicity is not fully understood, although it is related to reactive oxygen and nitrogen species, oxidative stress, DNA damage, poly (ADP-ribose) polymerase activation within the affected cell. We, therefore, made an attempt whether epigenetic aberrations may contribute to pathogenesis of SM poisoning in rats' lung. A total of 40 male SD rats were divided into 4 groups. Group 1 served as control and given 2 ml saline, three groups received single dose of mechlorethamine (MEC) (3.5 mg/kg subcutaneously) with the same time intervals. Group 2 received MEC only; group 3 received histone deacetylase (HDAC) inhibitor (Trichostatine A) (1 mg/kg) and group 4 received DNA methyl transferase (DNMT) inhibitor (5-Azacytidine) (0.02 mg/kg), intraperitoneally. MEC injection resulted in severe lung toxicity with strong interstitial and alveolar edema, hemorrhage, emphysematous changes as well as mild inflammatory cell infiltration and septal thickening. In group 3, the HDAC inhibitor significantly reduced interstitial and alveolar edema, hemorrhage and inflammatory cell infiltration. On the other hand, we have observed severe lung damage by using DNMT inhibitor (group 4). In HDAC inhibitor group, the results were close to sham group. In DNMT inhibitor group, however, lungs were worse than MEC group results. These preliminary results revealed that, SM itself and/or its intracellular metabolites may perturb the epigenetic environment of the affected cell in lung tissue. Hypothetically, MEC may cause HDAC induction leading to a variety of gene silencing. Trichostatine A can reduce the active enzyme level and can reactivate the already silenced genes. Further studies are needed to clarify the involvement of epigenetic perturbations in the pathogenesis of mustard toxicity.(author)

Structure- and function-based design of Plasmodium-selective proteasome inhibitors.

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Li, Hao; O'Donoghue, Anthony J; van der Linden, Wouter A; Xie, Stanley C; Yoo, Euna; Foe, Ian T; Tilley, Leann; Craik, Charles S; da Fonseca, Paula C A; Bogyo, Matthew

2016-02-11

The proteasome is a multi-component protease complex responsible for regulating key processes such as the cell cycle and antigen presentation. Compounds that target the proteasome are potentially valuable tools for the treatment of pathogens that depend on proteasome function for survival and replication. In particular, proteasome inhibitors have been shown to be toxic for the malaria parasite Plasmodium falciparum at all stages of its life cycle. Most compounds that have been tested against the parasite also inhibit the mammalian proteasome, resulting in toxicity that precludes their use as therapeutic agents. Therefore, better definition of the substrate specificity and structural properties of the Plasmodium proteasome could enable the development of compounds with sufficient selectivity to allow their use as anti-malarial agents. To accomplish this goal, here we use a substrate profiling method to uncover differences in the specificities of the human and P. falciparum proteasome. We design inhibitors based on amino-acid preferences specific to the parasite proteasome, and find that they preferentially inhibit the β2-subunit. We determine the structure of the P. falciparum 20S proteasome bound to the inhibitor using cryo-electron microscopy and single-particle analysis, to a resolution of 3.6 Å. These data reveal the unusually open P. falciparum β2 active site and provide valuable information about active-site architecture that can be used to further refine inhibitor design. Furthermore, consistent with the recent finding that the proteasome is important for stress pathways associated with resistance of artemisinin family anti-malarials, we observe growth inhibition synergism with low doses of this β2-selective inhibitor in artemisinin-sensitive and -resistant parasites. Finally, we demonstrate that a parasite-selective inhibitor could be used to attenuate parasite growth in vivo without appreciable toxicity to the host. Thus, the Plasmodium proteasome is a

Structure and function based design of Plasmodium-selective proteasome inhibitors

Science.gov (United States)

Li, Hao; O'Donoghue, Anthony J.; van der Linden, Wouter A.; Xie, Stanley C.; Yoo, Euna; Foe, Ian T.; Tilley, Leann; Craik, Charles S.; da Fonseca, Paula C. A.; Bogyo, Matthew

2016-01-01

The proteasome is a multi-component protease complex responsible for regulating key processes such as the cell cycle and antigen presentation1. Compounds that target the proteasome are potentially valuable tools for the treatment of pathogens that depend on proteasome function for survival and replication. In particular, proteasome inhibitors have been shown to be toxic for the malaria parasite Plasmodium falciparum at all stages of its life cycle2-5. Most compounds that have been tested against the parasite also inhibit the mammalian proteasome resulting in toxicity that precludes their use as therapeutic agents2,6. Therefore, better definition of the substrate specificity and structural properties of the Plasmodium proteasome could enable the development of compounds with sufficient selectivity to allow their use as anti-malarial agents. To accomplish this goal, we used a substrate profiling method to uncover differences in the specificities of the human and P. falciparum proteasome. We designed inhibitors based on amino acid preferences specific to the parasite proteasome, and found that they preferentially inhibit the β 2 subunit. We determined the structure of the P. falciparum 20S proteasome bound to the inhibitor using cryo-electron microscopy (cryo-EM) and single particle analysis, to a resolution of 3.6 Å. These data reveal the unusually open P. falciparum β2 active site and provide valuable information regarding active site architecture that can be used to further refine inhibitor design. Furthermore, consistent with the recent finding that the proteasome is important for stress pathways associated with resistance of artemisinin (ART) family anti-malarials7,8, we observed growth inhibition synergism with low doses of this β 2 selective inhibitor in ART sensitive and resistant parasites. Finally, we demonstrated that a parasite selective inhibitor could be used to attenuate parasite growth in vivo without significant toxicity to the host. Thus, the

Non toxic biodegradable cationic gemini surfactants as novel corrosion inhibitor for mild steel in hydrochloric acid medium and synergistic effect of sodium salicylate: Experimental and theoretical approach

Energy Technology Data Exchange (ETDEWEB)

Mobin, Mohammad, E-mail: drmmobin@hotmail.com; Aslam, Ruby; Aslam, Jeenat

2017-04-15

Two biodegradable, non toxic cationic gemini surfactants having ester linkage in the spacer namely, C{sub m}H{sub 2m+1}(CH{sub 3}){sub 2}N{sup +}(CH{sub 2}COOCH{sub 2}){sub 2}N{sup +}(CH{sub 3}){sub 2}C{sub m}H{sub 2m+1}.2Cl{sup -} (m-E2-m, m = 12, 14), were synthesized and characterized using elemental analysis, FT-IR and {sup 1}H-NMR. The corrosion inhibition performance of synthesized compounds separately and in combination with sodium salicylate (SS), along with the nature and stability of inhibitive film, for mild steel (MS) in 1 M HCl solution at 30–60 °C was evaluated using weight loss, potentiodynamic polarization, EIS, UV–visible spectroscopy, FTIR, SEM/EDAX, TGA and quantum chemical calculations. Results of the studies confirm m-E2-m as effective corrosion inhibitor for MS in HCl; the inhibition effect being synergistically strengthened in presence of SS. The synthesized compounds act as mixed type inhibitor and adsorb on MS surface in accordance with Langmuir adsorption isotherm. Experimentally measured inhibition efficiencies are correlated with the molecular parameters obtained using PM6 semi-empirical method. Empirical results are in good agreement with the theoretical predictions. - Graphical abstract: (a) Optimized geometry of studied inhibitors by PM6 method with (b) HOMO and (c) LUMO orbital occupation. - Highlights: • Environment friendly gemini surfactants were studied as corrosion inhibitor for MS. • Studied compounds act as good inhibitor for MS corrosion in 1 M HCl at 30–60 °C. • η of inhibitors is synergistically increased in presence of sodium salicylate. • The synthesized cationic gemini surfactants act as mixed-type inhibitor. • Experimentally obtained results are in good agreement with theoretical results.

ATOPIC DERMATITIS: NEW ASPECTS OF TREATMENT

Directory of Open Access Journals (Sweden)

D. Sh. Macharadze

2013-01-01

Full Text Available Atopic dermatitis is a chronic inflammatory cutaneous disease, which demands a prolonged treatment. A modern views on the main approaches to treatment of atopic dermatitis in children and adults are analyzed in this article. The treatment is based on the permanent use of emollients in order to achieve an anti-inflammatory effect — topical calcineurin inhibitors (tacrolimus and pimecrolimus, and short courses (5 days of topical corticosteroids during relapses. For the 10-year period of topical calcineurin inhibitors usage in treatment of atopic dermatitis a great amount of experimental and clinical data have been accumulated. Two the most important changes and additions in the treatment of atopic dermatitis in recent times were related to a new hypothesis of proactive therapy with the use of topical tacrolimus and closing of «black box» warnings, associated to malignization risk due to the long-term usage of topical calcineurin inhibitors. Since atopic dermatitis is characterized by relapsing course, nowadays topical tacrolimus should be considered the most appropriate treatment approach, both in adults and children. The results of investigations confirmed more than 6-times decrease in relapse rate, as well as the significant improvement of quality of life, when the above-mentioned treatment scheme is used, both in children and adults.Key words: children, atopic dermatitis, emollients, treatment, tacrolimus.

High-efficiency liposomal encapsulation of a tyrosine kinase inhibitor leads to improved in vivo toxicity and tumor response profile

Directory of Open Access Journals (Sweden)

Mukthavaram R

2013-10-01

Full Text Available Rajesh Mukthavaram,1 Pengfei Jiang,1 Rohit Saklecha,1 Dmitri Simberg,3,4 Ila Sri Bharati,1 Natsuko Nomura,1 Ying Chao,1 Sandra Pastorino,1 Sandeep C Pingle,1 Valentina Fogal,1 Wolf Wrasidlo,1,2 Milan Makale,1,2 Santosh Kesari1,21Translational Neuro-Oncology Laboratories, 2Department of Neurosciences, 3Solid Tumor Therapeutics Program, Moores Cancer Center, UC San Diego, La Jolla, CA, 4Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Denver, CO, USAAbstract: Staurosporine (STS is a potent pan-kinase inhibitor with marked activity against several chemotherapy-resistant tumor types in vitro. The translational progress of this compound has been hindered by poor pharmacokinetics and toxicity. We sought to determine whether liposomal encapsulation of STS would enhance antitumor efficacy and reduce toxicity, thereby supporting the feasibility of further preclinical development. We developed a novel reverse pH gradient liposomal loading method for STS, with an optimal buffer type and drug-to-lipid ratio. Our approach produced 70% loading efficiency with good retention, and we provide, for the first time, an assessment of the in vivo antitumor activity of STS. A low intravenous dose (0.8 mg/kg inhibited U87 tumors in a murine flank model. Biodistribution showed preferential tumor accumulation, and body weight data, a sensitive index of STS toxicity, was unaffected by liposomal STS, but did decline with the free compound. In vitro experiments revealed that liposomal STS blocked Akt phosphorylation, induced poly(ADP-ribose polymerase cleavage, and produced cell death via apoptosis. This study provides a basis to explore further the feasibility of liposomally encapsulated STS, and potentially related compounds for the management of resistant solid tumors.Keywords: liposomes, staurosporine, glioblastoma, biodistribution, efficacy

Practices in management of cancer treatment-related cardiovascular toxicity: A cardio-oncology survey.

Science.gov (United States)

Jovenaux, Ludovic; Cautela, Jennifer; Resseguier, Noemie; Pibarot, Michele; Taouqi, Myriam; Orabona, Morgane; Pinto, Johan; Peyrol, Michael; Barraud, Jeremie; Laine, Marc; Bonello, Laurent; Paganelli, Franck; Barlesi, Fabrice; Thuny, Franck

2017-08-15

Cardiovascular toxicity has become a challenging issue during cancer therapy. Nonetheless, there is a lack of consensual guidelines for their management. We aimed to determine the current practices of oncologists regarding cardiovascular toxicity related to anthracyclines, trastuzumab and angiogenic inhibitors and to gather their opinions on the development of cardio-oncology programs. A cross-sectional declarative study was submitted to French oncologists in the form of an individual, structured questionnaire. A total of 303 oncologists responded to the survey. Ninety-nine percent of oncologists prescribed cardiotoxic therapies, including anthracyclines (83%), trastuzumab (51%) and other angiogenic inhibitors (64%). The method adopted for managing cardiovascular toxicity was based on guidelines from expert oncology societies for only 35% of oncologists. None was aware of recommendations from expert cardiology societies. Prescription of pre-, peri- and post-therapy cardiovascular assessment was inconsistent and significantly less frequent for all classes of angiogenic inhibitors than for anthracyclines and trastuzumab (Poncology programs development. Practices of oncologists are disparate in the field of cardiovascular toxicity. This finding underlines the complexity of managing many different situations and the need for distribution of formal guidelines from oncology and cardiology expert societies. The development of personalized cardio-oncology programs seems essential. Copyright © 2017 Elsevier B.V. All rights reserved.

Hsp90 chaperone inhibitor 17-AAG attenuates Aβ-induced synaptic toxicity and memory impairment.

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Chen, Yaomin; Wang, Bin; Liu, Dan; Li, Jing Jing; Xue, Yueqiang; Sakata, Kazuko; Zhu, Ling-qiang; Heldt, Scott A; Xu, Huaxi; Liao, Francesca-Fang

2014-02-12

The excessive accumulation of soluble amyloid peptides (Aβ) plays a crucial role in the pathogenesis of Alzheimer's disease (AD), particularly in synaptic dysfunction. The role of the two major chaperone proteins, Hsp70 and Hsp90, in clearing misfolded protein aggregates has been established. Despite their abundant presence in synapses, the role of these chaperones in synapses remains elusive. Here, we report that Hsp90 inhibition by 17-AAG elicited not only a heat shock-like response but also upregulated presynaptic and postsynaptic proteins, such as synapsin I, synaptophysin, and PSD95 in neurons. 17-AAG treatment enhanced high-frequency stimulation-evoked LTP and protected neurons from synaptic damage induced by soluble Aβ. In AD transgenic mice, the daily administration of 17-AAG over 7 d resulted in a marked increase in PSD95 expression in hippocampi. 17-AAG treatments in wild-type C57BL/6 mice challenged by soluble Aβ significantly improved contextual fear memory. Further, we demonstrate that 17-AAG activated synaptic protein expression via transcriptional mechanisms through the heat shock transcription factor HSF1. Together, our findings identify a novel function of Hsp90 inhibition in regulating synaptic plasticity, in addition to the known neuroprotective effects of the chaperones against Aβ and tau toxicity, thus further supporting the potential of Hsp90 inhibitors in treating neurodegenerative diseases.

E2/ER β Enhances Calcineurin Protein Degradation and PI3K/Akt/MDM2 Signal Transduction to Inhibit ISO-Induced Myocardial Cell Apoptosis

Directory of Open Access Journals (Sweden)

Kuan-Ho Lin

2017-04-01

Full Text Available Secretion of multifunctional estrogen and its receptor has been widely considered as the reason for markedly higher frequency of heart disease in men than in women. 17β-Estradiol (E2, for instance, has been reported to prevent development of cardiac apoptosis via activation of estrogen receptors (ERs. In addition, protein phosphatase such as protein phosphatase 1 (PP1 and calcineurin (PP2B are also involved in cardiac hypertrophy and cell apoptosis signaling. However, the mechanism by which E2/ERβ suppresses apoptosis is not fully understood, and the role of protein phosphatase in E2/ERβ action also needs further investigation. In this study, we observed that E2/ERβ inhibited isoproterenol (ISO-induced myocardial cell apoptosis, cytochrome c release and downstream apoptotic markers. Moreover, we found that E2/ERβ blocks ISO-induced apoptosis in H9c2 cells through the enhancement of calcineurin protein degradation through PI3K/Akt/MDM2 signaling pathway. Our results suggest that supplementation with estrogen and/or overexpression of estrogen receptor β gene may prove to be effective means to treat stress-induced myocardial damage.

Recommendations of everolimus use in liver transplant.

Science.gov (United States)

Rubín Suárez, Angel; Bilbao Aguirre, Itxarone; Fernández-Castroagudin, Javier; Pons Miñano, José Antonio; Salcedo Plaza, Magdalena; Varo Pérez, Evaristo; Prieto Castillo, Martín

2017-11-01

Mammalian target of rapamycin (mTOR) inhibitors, everolimus (EVL) and sirolimus are immunosuppressive agents with a minor nephrotoxic effect, limited to the development of proteinuria in some cases. The combination of EVL and low-dose tacrolimus has proven to be as safe and effective as standard therapy with tacrolimus for the prevention of acute cellular rejection. Early initiation of EVL-based immunosuppressive regimens with reduced exposure to calcineurin inhibitors has been shown to significantly improve renal function of LT recipients during induction and maintenance phases, with comparable efficacy and safety profiles. In patients with established kidney failure, initiating EVL may enable clinicians to reduce calcineurin inhibitors exposure, thereby contributing to the improved renal function of these patients. Although there is not sufficient evidence to recommend their use to prevent the recurrence of hepatocellular carcinoma and the progression of de novo tumours, they are used in this context in routine clinical practice. Copyright © 2017 Elsevier España, S.L.U., AEEH y AEG. All rights reserved.

Assessing subunit dependency of the Plasmodium proteasome using small molecule inhibitors and active site probes.

Science.gov (United States)

Li, Hao; van der Linden, Wouter A; Verdoes, Martijn; Florea, Bogdan I; McAllister, Fiona E; Govindaswamy, Kavitha; Elias, Joshua E; Bhanot, Purnima; Overkleeft, Herman S; Bogyo, Matthew

2014-08-15

The ubiquitin-proteasome system (UPS) is a potential pathway for therapeutic intervention for pathogens such as Plasmodium, the causative agent of malaria. However, due to the essential nature of this proteolytic pathway, proteasome inhibitors must avoid inhibition of the host enzyme complex to prevent toxic side effects. The Plasmodium proteasome is poorly characterized, making rational design of inhibitors that induce selective parasite killing difficult. In this study, we developed a chemical probe that labels all catalytic sites of the Plasmodium proteasome. Using this probe, we identified several subunit selective small molecule inhibitors of the parasite enzyme complex. Treatment with an inhibitor that is specific for the β5 subunit during blood stage schizogony led to a dramatic decrease in parasite replication while short-term inhibition of the β2 subunit did not affect viability. Interestingly, coinhibition of both the β2 and β5 catalytic subunits resulted in enhanced parasite killing at all stages of the blood stage life cycle and reduced parasite levels in vivo to barely detectable levels. Parasite killing was achieved with overall low host toxicity, something that has not been possible with existing proteasome inhibitors. Our results highlight differences in the subunit dependency of the parasite and human proteasome, thus providing a strategy for development of potent antimalarial drugs with overall low host toxicity.

Induction by anti-thymocyte globulins in kidney transplantation: a review of the literature and current usage.

Science.gov (United States)

Malvezzi, Paolo; Jouve, Thomas; Rostaing, Lionel

2015-10-01

Preventing acute rejection (AR) after kidney transplantation is of utmost importance because an AR can have a negative impact on long-term allograft survival. Directory of Open Access Journals (DOAJ), Google Scholar, PubMed, EBSCO, and Web of Science have been searched. At the moment this can be done by using rabbit anti-thymocyte globulins (rATGs) as an induction therapy. However, because rATGs are associated with some deleterious side-effects, such as the opportunistic infections cytomegalovirus (CMV) and de novo post-transplant cancer, it is very important they are used optimally, i.e., at minimal doses that avoid many side-effects but still retain optimal treatment efficacy. Recent data show that the risk of CMV infection can be minimized using tacrolimus plus everolimus, and not tacrolimus plus mycophenolic acid, as the maintenance immunosuppression. The use of rATG is particularly valuable in; (a) sensitized patients; (b) in recipients from an expanded-criteria donor, thus enabling the introduction of calcineurin inhibitors at reduced doses; and (c) for patients where steroid avoidance is contemplated. However, we also need to consider that rATG may increase the risk of de novo cancer, even though recent data indicate this is unlikely and that any risk can be reduced by using mammalian target of rapamycin (mTOR) inhibitors instead of mycophenolic acid combined with low-dose calcineurin inhibitors. Even though rATGs do not improve long-term kidney-allograft survival, they may help reduce calcineurin-inhibitor dosage during the early post-transplant period and minimize the risk of AR.

Unilateral vestibular deafferentation-induced changes in calcium signaling-related molecules in the rat vestibular nuclear complex.

Science.gov (United States)

Masumura, Chisako; Horii, Arata; Mitani, Kenji; Kitahara, Tadashi; Uno, Atsuhiko; Kubo, Takeshi

2007-03-23

Inquiries into the neurochemical mechanisms of vestibular compensation, a model of lesion-induced neuronal plasticity, reveal the involvement of both voltage-gated Ca(2+) channels (VGCC) and intracellular Ca(2+) signaling. Indeed, our previous microarray analysis showed an up-regulation of some calcium signaling-related genes such as the alpha2 subunit of L-type calcium channels, calcineurin, and plasma membrane Ca(2+) ATPase 1 (PMCA1) in the ipsilateral vestibular nuclear complex (VNC) following unilateral vestibular deafferentation (UVD). To further elucidate the role of calcium signaling-related molecules in vestibular compensation, we used a quantitative real-time polymerase chain reaction (PCR) method to confirm the microarray results and investigated changes in expression of these molecules at various stages of compensation (6 h to 2 weeks after UVD). We also investigated the changes in gene expression during Bechterew's phenomenon and the effects of a calcineurin inhibitor on vestibular compensation. Real-time PCR showed that genes for the alpha2 subunit of VGCC, PMCA2, and calcineurin were transiently up-regulated 6 h after UVD in ipsilateral VNC. A subsequent UVD, which induced Bechterew's phenomenon, reproduced a complete mirror image of the changes in gene expressions of PMCA2 and calcineurin seen in the initial UVD, while the alpha2 subunit of VGCC gene had a trend to increase in VNC ipsilateral to the second lesion. Pre-treatment by FK506, a calcineurin inhibitor, decelerated the vestibular compensation in a dose-dependent manner. Although it is still uncertain whether these changes in gene expression are causally related to the molecular mechanisms of vestibular compensation, this observation suggests that after increasing the Ca(2+) influx into the ipsilateral VNC neurons via up-regulated VGCC, calcineurin may be involved in their synaptic plasticity. Conversely, an up-regulation of PMCA2, a brain-specific Ca(2+) pump, would increase an efflux of Ca

Investigations into the origin of the molecular recognition of several adenosine deaminase inhibitors.

Science.gov (United States)

Gillerman, Irina; Fischer, Bilha

2011-01-13

Inhibitors of adenosine deaminase (ADA, EC 3.5.4.4) are potential therapeutic agents for the treatment of various health disorders. Several highly potent inhibitors were previously identified, yet they exhibit unacceptable toxicities. We performed a SAR study involving a series of C2 or C8 substituted purine-riboside analogues with a view to discover less potent inhibitors with a lesser toxicity. We found that any substitution at C8 position of nebularine resulted in total loss of activity toward calf intestinal ADA. However, several 2-substituted-adenosine, 8-aza-adenosine, and nebularine analogues exhibited inhibitory activity. Specifically, 2-Cl-purine riboside, 8-aza-2-thiohexyl adenosine, 2-thiohexyl adenosine, and 2-MeS-purine riboside were found to be competitive inhibitors of ADA with K(i) values of 25, 22, 6, and 3 μM, respectively. We concluded that electronic parameters are not major recognition determinants of ADA but rather steric parameters. A C2 substituent which fits ADA hydrophobic pocket and improves H-bonding with the enzyme makes a good inhibitor. In addition, a gg rotamer about C4'-C5' bond is apparently an important recognition determinant.

Pathophysiological significance and therapeutic applications of snake venom protease inhibitors.

Science.gov (United States)

Thakur, Rupamoni; Mukherjee, Ashis K

2017-06-01

Protease inhibitors are important constituents of snake venom and play important roles in the pathophysiology of snakebite. Recently, research on snake venom protease inhibitors has provided valuable information to decipher the molecular details of various biological processes and offer insight for the development of some therapeutically important molecules from snake venom. The process of blood coagulation and fibrinolysis, in addition to affecting platelet function, are well known as the major targets of several snake venom protease inhibitors. This review summarizes the structure-functional aspects of snake venom protease inhibitors that have been described to date. Because diverse biological functions have been demonstrated by protease inhibitors, a comparative overview of their pharmacological and pathophysiological properties is also highlighted. In addition, since most snake venom protease inhibitors are non-toxic on their own, this review evaluates the different roles of individual protease inhibitors that could lead to the identification of drug candidates and diagnostic molecules. Copyright © 2017 Elsevier Ltd. All rights reserved.

New pyridine derivatives as inhibitors of acetylcholinesterase and amyloid aggregation.

Science.gov (United States)

Pandolfi, Fabiana; De Vita, Daniela; Bortolami, Martina; Coluccia, Antonio; Di Santo, Roberto; Costi, Roberta; Andrisano, Vincenza; Alabiso, Francesco; Bergamini, Christian; Fato, Romana; Bartolini, Manuela; Scipione, Luigi

2017-12-01

A new series of pyridine derivatives with carbamic or amidic function has been designed and synthesized to act as cholinesterase inhibitors. The synthesized compounds were tested toward EeAChE and hAChE and toward eqBChE and hBChE. The carbamate 8 was the most potent hAChE inhibitor (IC 50  = 0.153 ± 0.016 μM) while the carbamate 11 was the most potent inhibitor of hBChE (IC 50  = 0.828 ± 0.067 μM). A molecular docking study indicated that the carbamate 8 was able to bind AChE by interacting with both CAS and PAS, in agreement with the mixed inhibition mechanism. Furthermore, the carbamates 8, 9 and 11 were able to inhibit Aβ 42 self-aggregation and possessed quite low toxicity against human astrocytoma T67 and HeLa cell lines, being the carbamate 8 the less toxic compound on both cell lines. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

MicroRNA as biomarkers of mitochondrial toxicity

Energy Technology Data Exchange (ETDEWEB)

Baumgart, Bethany R., E-mail: bethany.baumgart@bms.com [Department of Toxicology, Drug Safety Evaluation, Bristol-Myers Squibb, 4401 Highway 62 East, Mount Vernon, IN 47620 (United States); Gray, Katherine L. [Department of Toxicology, Drug Safety Evaluation, Bristol-Myers Squibb, 4401 Highway 62 East, Mount Vernon, IN 47620 (United States); Woicke, Jochen [Department of Pathology, Drug Safety Evaluation, Bristol-Myers Squibb, 4401 Highway 62 East, Mount Vernon, IN 47620 (United States); Bunch, Roderick T.; Sanderson, Thomas P. [Department of Toxicology, Drug Safety Evaluation, Bristol-Myers Squibb, 4401 Highway 62 East, Mount Vernon, IN 47620 (United States); Van Vleet, Terry R. [Department of Investigative Toxicology and Pathology, Abbvie, 1 N. Waukegan Rd., North Chicago, IL 60064-6123, USA. (United States)

2016-12-01

Mitochondrial toxicity can be difficult to detect as most cells can tolerate reduced activity as long as minimal capacity for function is maintained. However, once minimal capacity is lost, apoptosis or necrosis occurs quickly. Identification of more sensitive, early markers of mitochondrial toxicity was the objective of this work. Rotenone, a mitochondrial complex I inhibitor, and 3-nitropropionic acid (3-NP), a mitochondrial complex II inhibitor, were administered daily to male Sprague–Dawley rats at subcutaneous doses of 0.1 or 0.3 mg/kg/day and intraperitoneal doses of 5 or 10 mg/kg/day, respectively, for 1 week. Samples of kidney, skeletal muscle (quadriceps femoris), and serum were collected for analysis of mitochondrial DNA (mtDNA) copy number and microRNA (miRNA) expression patterns. MtDNA was significantly decreased with administration of rotenone at 0.3 mg/kg/day and 3-NP at 5 and 10 mg/kg/day in the quadriceps femoris and with 3-NP at 10 mg/kg/day in the kidney. Additionally, rotenone and 3-NP treatment produced changes to miRNA expression that were similar in direction (i.e. upregulation, downregulation) to those previously linked to mitochondrial functions, such as mitochondrial damage and biogenesis (miR-122, miR-202-3p); regulation of ATP synthesis, abolished oxidative phosphorylation, and loss of membrane potential due to increased reactive oxygen species (ROS) production (miR-338-5p, miR-546, miR-34c); and mitochondrial DNA damage and depletion (miR-546). These results suggest that miRNAs may be sensitive biomarkers for early detection of mitochondrial toxicity. - Highlights: • MtDNA decreased after treatment with respiratory chain inhibitors rotenone and 3-NP. • Decrease in mtDNA is generally dose-related and indicative of mitochondrial toxicity. • Altered miRNA has reported roles in regulating mitochondrial function. • Induction of miR-338-5p in kidney and serum suggests potential as renal biomarker. • Induction of miR-122 implies

Predicting the Performance of Organic Corrosion Inhibitors

Directory of Open Access Journals (Sweden)

David A. Winkler

2017-12-01

Full Text Available The withdrawal of effective but toxic corrosion inhibitors has provided an impetus for the discovery of new, benign organic compounds to fill that role. Concurrently, developments in the high-throughput synthesis of organic compounds, the establishment of large libraries of available chemicals, accelerated corrosion inhibition testing technologies, and the increased capability of machine learning methods have made discovery of new corrosion inhibitors much faster and cheaper than it used to be. We summarize these technical developments in the corrosion inhibition field and describe how data-driven machine learning methods can generate models linking molecular properties to corrosion inhibition that can be used to predict the performance of materials not yet synthesized or tested. We briefly summarize the literature on quantitative structure–property relationships models of small organic molecule corrosion inhibitors. The success of these models provides a paradigm for rapid discovery of novel, effective corrosion inhibitors for a range of metals and alloys in diverse environments.

Cellular growth kinetics distinguish a cyclophilin inhibitor from an HSP90 inhibitor as a selective inhibitor of hepatitis C virus.

Directory of Open Access Journals (Sweden)

Rudolf K F Beran

Full Text Available During antiviral drug discovery, it is critical to distinguish molecules that selectively interrupt viral replication from those that reduce virus replication by adversely affecting host cell viability. In this report we investigate the selectivity of inhibitors of the host chaperone proteins cyclophilin A (CypA and heat-shock protein 90 (HSP90 which have each been reported to inhibit replication of hepatitis C virus (HCV. By comparing the toxicity of the HSP90 inhibitor, 17-(Allylamino-17-demethoxygeldanamycin (17-AAG to two known cytostatic compounds, colchicine and gemcitabine, we provide evidence that 17-AAG exerts its antiviral effects indirectly through slowing cell growth. In contrast, a cyclophilin inhibitor, cyclosporin A (CsA, exhibited selective antiviral activity without slowing cell proliferation. Furthermore, we observed that 17-AAG had little antiviral effect in a non-dividing cell-culture model of HCV replication, while CsA reduced HCV titer by more than two orders of magnitude in the same model. The assays we describe here are useful for discriminating selective antivirals from compounds that indirectly affect virus replication by reducing host cell viability or slowing cell growth.

Green chemistry applied to corrosion and scale inhibitors

Energy Technology Data Exchange (ETDEWEB)

Darling, D.; Rakshpal, R. [Environmental Protection Agency, Washington, DC (United States)

1998-12-31

Numerous breakthroughs in environmental protection and pollution prevention have been realized in recent years by both industry and academia through the application of green chemistry principles. Green chemistry, or pollution prevention at the molecular level, is chemistry designed to reduce or eliminate the use or generation of hazardous materials associated with the manufacture and application of chemicals. The application of the green chemistry principles to the areas of corrosion and scale inhibitors has resulted in the reduction/elimination of many of the more toxic inhibitors and the development of newer, more environmentally friendly ones.

Do non-nucleoside reverse transcriptase inhibitors contribute to lipodystrophy?

Science.gov (United States)

Nolan, David

2005-01-01

Lipodystrophy complications, including lipoatrophy (pathological fat loss) and metabolic complications, have emerged as important long-term toxicities associated with antiretroviral therapy in the current era. The wealth of data that has accumulated over the past 6 years has now clarified the contribution of specific antiretroviral drugs to the risk of these clinical endpoints, with evidence that lipoatrophy is strongly associated with the choice of nucleoside reverse transcriptase inhibitor therapy (specifically, stavudine and to a lesser extent zidovudine). The aetiological basis of metabolic complications of antiretroviral therapy has proven to be complex, in that the risk appears to be modulated by a number of lifestyle factors that have made the metabolic syndrome highly prevalent in the general population, with additional contributions from HIV disease status itself, as well as from individual drugs within the HIV protease inhibitor class. The currently licensed non-nucleoside reverse transcriptase inhibitor (NNRTI) drugs, efavirenz and nevirapine, have been proven to have a favourable safety profile in terms of lipodystrophy complications. However, it must be noted that NNRTI drugs also have individual toxicity profiles that must be accounted for when considering and/or monitoring their use in the treatment of HIV infection.

Glucocorticoids and Polyamine Inhibitors Synergize to Kill Human Leukemic CEM Cells

Directory of Open Access Journals (Sweden)

Aaron L. Miller

2002-01-01

Full Text Available Glucocorticoids are well-known apoptotic agents in certain classes of lymphoid cell malignancies. Reduction of intracellular polyamine levels by use of inhibitors that block polyamine synthesis slows or inhibits growth of many cells in vitro. Several such inhibitors have shown efficacy in clinical trials, though the toxicity of some compounds has limited their usefulness. We have tested the effects of combinations of the glucocorticoid dexamethasone. (20Dex and two polyamine inhibitors, difluoromethylornithine. (20DFMO and methyl glyoxal bis guanylhydrazone. (20MGBG, on the clonal line of human acute lymphoblastic leukemia cells, CEM-C7-14. Dex alone kills these cells, though only after a delay of at least 24 hours. We also evaluated a partially glucocorticoid-resistant c-Myc-expressing CEM-C7-14 clone. We show that Dex downregulates ornithine decarboxylase. (20ODC, the rate-limiting enzyme in polyamine synthesis. Pretreatment with the ODC inhibitor DFMO, followed by addition of Dex, enhances steroid-evoked kill slightly. The combination of pretreatment with sublethal concentrations of both DFMO and the inhibitor of S-adenosylmethionine decarboxylase, MGBG, followed by addition of Dex, results in strong synergistic cell kill. Both the rapidity and extent of cell kill are enhanced compared to the effects of Dex alone. These results suggest that use of such combinations in vivo may result in apoptosis of malignant cells with lower overall toxicity.

Novel Insights into Structure-Activity Relationships of N-Terminally Modified PACE4 Inhibitors.

Science.gov (United States)

Kwiatkowska, Anna; Couture, Frédéric; Levesque, Christine; Ly, Kévin; Beauchemin, Sophie; Desjardins, Roxane; Neugebauer, Witold; Dory, Yves L; Day, Robert

2016-02-04

PACE4 plays important roles in prostate cancer cell proliferation. The inhibition of this enzyme has been shown to slow prostate cancer progression and is emerging as a promising therapeutic strategy. In previous work, we developed a highly potent and selective PACE4 inhibitor, the multi-Leu (ML) peptide, an octapeptide with the sequence Ac-LLLLRVKR-NH2 . Here, with the objective of developing a useful compound for in vivo administration, we investigate the effect of N-terminal modifications. The inhibitory activity, toxicity, stability, and cell penetration properties of the resulting analogues were studied and compared to the unmodified inhibitor. Our results show that the incorporation of a polyethylene glycol (PEG) moiety leads to a loss of antiproliferative activity, whereas the attachment of a lipid chain preserves or improves it. However, the lipidated peptides are significantly more toxic when compared with their unmodified counterparts. Therefore, the best results were achieved not by the N-terminal extension but by the protection of both ends with the d-Leu residue and 4-amidinobenzylamide, which yielded the most stable inhibitor, with an excellent activity and toxicity profile. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Interprofessional Collaboration with Immune Checkpoint Inhibitor Therapy: the Roles of Gastroenterology, Endocrinology and Neurology.

Science.gov (United States)

Seery, Virginia

2017-11-01

To discuss immune checkpoint inhibitor therapy and identify opportunities for interprofessional collaboration in the management of toxicities in the areas of gastroenterology, endocrinology, and neurology. Published research and education articles in oncology, nursing, and various specialties. The use of immune checkpoint inhibitors is expanding; timely management of toxicity is critical for positive patient outcomes. There are many opportunities for interprofessional collaboration in the diagnosis and treatment of immune-related adverse events. Nurses play key roles in recognizing immune-related adverse events, providing patient education, and helping to facilitate interprofessional collaboration. Copyright © 2017 Elsevier Inc. All rights reserved.

JANEX-1, a JAK3 inhibitor, protects pancreatic islets from cytokine toxicity through downregulation of NF-{kappa}B activation and the JAK/STAT pathway

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Lv, Na; Kim, Eun-Kyung; Song, Mi-Young [Department of Biochemistry, Medical School and Diabetes Research Center, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Choi, Ha-Na; Moon, Woo Sung [Department of Pathology, Medical School and Diabetes Research Center, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Park, Sung-Joo [Department of Herbology, School of Oriental Medicine, Wonkwang University, Iksan, Jeonbuk 570-749 (Korea, Republic of); Park, Jin-Woo [Department of Biochemistry, Medical School and Diabetes Research Center, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Kwon, Kang-Beom, E-mail: desson@wonkwang.ac.kr [Department of Physiology, School of Oriental Medicine, Wonkwang University, Iksan, Jeonbuk 570-749 (Korea, Republic of); Park, Byung-Hyun, E-mail: bhpark@chonbuk.ac.kr [Department of Biochemistry, Medical School and Diabetes Research Center, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of)

2009-07-15

JANEX-1/WHI-P131, a selective Janus kinase 3 (JAK3) inhibitor, has been shown to delay the onset of diabetes in the NOD mouse model. However, the molecular mechanism by which JANEX-1 protects pancreatic {beta}-cells is unknown. In the current study, we investigated the role of JANEX-1 on interleukin (IL)-1{beta} and interferon (IFN)-{gamma}-induced {beta}-cell damage using isolated islets. JANEX-1-pretreated islets showed resistance to cytokine toxicity, namely suppressed nitric oxide (NO) production, reduced inducible form of NO synthase (iNOS) expression, and decreased islet destruction. The molecular mechanism by which JANEX-1 inhibits iNOS expression was mediated through suppression of the nuclear factor {kappa}B (NF-{kappa}B) and JAK/signal transducer and activator of transcription (STAT) pathways. Islets treated with the cytokines downregulated the protein levels of suppressor of cytokine signaling (SOCS)-1 and SOCS-3, but pretreatment with JANEX-1 attenuated these decreases. Additionally, islets from JAK3{sup -/-} mice were more resistant to cytokine toxicity than islets from control mice. These results demonstrate that JANEX-1 protects {beta}-cells from cytokine toxicity through suppression of the NF-{kappa}B and JAK/STAT pathways and upregulation of SOCS proteins, suggesting that JANEX-1 may be used to preserve functional {beta}-cell mass.

PI3Kδ-selective and PI3Kα/δ-combinatorial inhibitors in clinical development for B-cell non-Hodgkin lymphoma.

Science.gov (United States)

Lampson, Benjamin L; Brown, Jennifer R

2017-11-01

The efficacy of the prototypical phosphatidylinositol-3-kinase (PI3K) inhibitor idelalisib for the treatment of chronic lymphocytic leukemia (CLL) and indolent non-Hodgkin lymphoma (iNHL) has led to development of multiple compounds targeting this pathway. Areas Covered: We review the hypothesized therapeutic mechanisms of PI3K inhibitors, including abrogation of B cell receptor signaling, blockade of microenvironmental pro-survival signals, and enhancement of anti-tumor immunity. We examine toxicities of idelalisib, including bacterial infections (possibly secondary to drug-induced neutropenia), opportunistic infections (possibly attributable to on-target inhibition of T cell function), and organ toxicities such as transaminitis and enterocolitis (possibly autoimmune, secondary to on-target inhibition of p110δ in regulatory T cells). We evaluate PI3K inhibitors that have entered trials for the treatment of lymphoma, focusing on agents with selectivity for PI3Kα and PI3Kδ. Expert Opinion: PI3K inhibitors, particularly those that target p110δ, have robust efficacy in the treatment of CLL and iNHL. However, idelalisib has infectious and autoimmune toxicities that limit its use. Outside of trials, idelalisib should be restricted to CLL patients with progression on ibrutinib or iNHL patients with progression on two prior therapies. Whether newer PI3K inhibitors will demonstrate differentiated toxicity profiles in comparable patient populations while retaining efficacy remains to be seen.

Place of mTOR inhibitors in management of BKV infection after kidney transplantation.

Science.gov (United States)

Jouve, Thomas; Rostaing, Lionel; Malvezzi, Paolo

2016-01-01

BK virus (BKV) viremia and BKV-associated nephropathy (BKVAN) have become a serious nuisance to kidney transplant (KT) patients since the mid-nineties, when the incidence of this disease has increased significantly. Directory of open access journals (DOAJ), EMBASE, Google Scholar, PubMed, EBSCO, and Web of Science have been searched. Many hypothesis have been made as to why this phenomenon has developed; it is of general opinion that a more potent immunosuppression is at the core of the problem. The use of the association of tacrolimus (TAC) with mycophenolic acid (MPA) has gained momentum in the same years as the increase in BKV viremia incidence making it seem to be the most likely culprit. m-TOR inhibitors (m-TORIs) have been shown to have antiviral properties in vitro and this fact has encouraged different transplant teams to use these agents when confronted with BKV infection (viremia or nephropathy). However, the results are mitigated. There had been conflicting results for example when converting from TAC-to sirolimus-based immunosuppression in the setting of established BKVAN. In order to prevent BKV infection we have to minimize to some extent immunosuppression, but it is not always possible, e.g. in high immunological risk patients. Conversely, we could use m-TORIs associated with low-dose calcineurin inhibitors (CNIs). This could be actually the key to a safe immunosuppression regimen both from the immunological stand point and from the viral one.

A pharmacologically-based array to identify targets of cyclosporine A-induced toxicity in cultured renal proximal tubule cells

International Nuclear Information System (INIS)

Sarró, Eduard; Jacobs-Cachá, Conxita; Itarte, Emilio; Meseguer, Anna

2012-01-01

Mechanisms of cyclosporine A (CsA)-induced nephrotoxicity were generally thought to be hemodynamic in origin; however, there is now accumulating evidence of a direct tubular effect. Although genomic and proteomic experiments by our group and others provided overall information on genes and proteins up- or down-regulated by CsA in proximal tubule cells (PTC), a comprehensive view of events occurring after CsA exposure remains to be described. For this purpose, we applied a pharmacologic approach based on the use of known activities of a large panel of potentially protective compounds and evaluated their efficacy in preventing CsA toxicity in cultured mouse PTC. Our results show that compounds that blocked protein synthesis and apoptosis, together with the CK2 inhibitor DMAT and the PI3K inhibitor apigenin, were the most efficient in preventing CsA toxicity. We also identified GSK3, MMPs and PKC pathways as potential targets to prevent CsA damage. Additionally, heparinase-I and MAPK inhibitors afforded partial but significant protection. Interestingly, antioxidants and calcium metabolism-related compounds were unable to ameliorate CsA-induced cytotoxicity. Subsequent experiments allowed us to clarify the hierarchical relationship of targeted pathways after CsA treatment, with ER stress identified as an early effector of CsA toxicity, which leads to ROS generation, phenotypical changes and cell death. In summary, this work presents a novel experimental approach to characterizing cellular responses to cytotoxics while pointing to new targets to prevent CsA-induced toxicity in proximal tubule cells. Highlights: ► We used a novel pharmacological approach to elucidate cyclosporine (CsA) toxicity. ► The ability of a broad range of compounds to prevent CsA toxicity was evaluated. ► CsA toxicity was monitored using LDH release assay and PARP cleavage. ► Protein synthesis, PI3K, GSK3, MMP, PKC and caspase inhibitors prevented CsA toxicity. ► We also identified ER

A pharmacologically-based array to identify targets of cyclosporine A-induced toxicity in cultured renal proximal tubule cells

Energy Technology Data Exchange (ETDEWEB)

Sarró, Eduard, E-mail: eduard.sarro@vhir.org [Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Biociències, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona) (Spain); Renal Physiopathology, CIBBIM-Nanomedicine, Vall d' Hebron Research Institute (VHIR), 08035 Barcelona (Spain); Jacobs-Cachá, Conxita, E-mail: conxita.jacobs@vhir.org [Renal Physiopathology, CIBBIM-Nanomedicine, Vall d' Hebron Research Institute (VHIR), 08035 Barcelona (Spain); Itarte, Emilio, E-mail: emili.itarte@uab.es [Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Biociències, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona) (Spain); Meseguer, Anna, E-mail: ana.meseguer@vhir.org [Renal Physiopathology, CIBBIM-Nanomedicine, Vall d' Hebron Research Institute (VHIR), 08035 Barcelona (Spain); Departament de Bioquimica i Biologia Molecular, Facultat de Medicina, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona) (Spain)

2012-01-15

Mechanisms of cyclosporine A (CsA)-induced nephrotoxicity were generally thought to be hemodynamic in origin; however, there is now accumulating evidence of a direct tubular effect. Although genomic and proteomic experiments by our group and others provided overall information on genes and proteins up- or down-regulated by CsA in proximal tubule cells (PTC), a comprehensive view of events occurring after CsA exposure remains to be described. For this purpose, we applied a pharmacologic approach based on the use of known activities of a large panel of potentially protective compounds and evaluated their efficacy in preventing CsA toxicity in cultured mouse PTC. Our results show that compounds that blocked protein synthesis and apoptosis, together with the CK2 inhibitor DMAT and the PI3K inhibitor apigenin, were the most efficient in preventing CsA toxicity. We also identified GSK3, MMPs and PKC pathways as potential targets to prevent CsA damage. Additionally, heparinase-I and MAPK inhibitors afforded partial but significant protection. Interestingly, antioxidants and calcium metabolism-related compounds were unable to ameliorate CsA-induced cytotoxicity. Subsequent experiments allowed us to clarify the hierarchical relationship of targeted pathways after CsA treatment, with ER stress identified as an early effector of CsA toxicity, which leads to ROS generation, phenotypical changes and cell death. In summary, this work presents a novel experimental approach to characterizing cellular responses to cytotoxics while pointing to new targets to prevent CsA-induced toxicity in proximal tubule cells. Highlights: ► We used a novel pharmacological approach to elucidate cyclosporine (CsA) toxicity. ► The ability of a broad range of compounds to prevent CsA toxicity was evaluated. ► CsA toxicity was monitored using LDH release assay and PARP cleavage. ► Protein synthesis, PI3K, GSK3, MMP, PKC and caspase inhibitors prevented CsA toxicity. ► We also identified ER

Vanadium Compounds as PTP Inhibitors

Directory of Open Access Journals (Sweden)

Elsa Irving

2017-12-01

Full Text Available Phosphotyrosine signaling is regulated by the opposing actions of protein tyrosine kinases (PTKs and protein tyrosine phosphatases (PTPs. Here we discuss the potential of vanadium derivatives as PTP enzyme inhibitors and metallotherapeutics. We describe how vanadate in the V oxidized state is thought to inhibit PTPs, thus acting as a pan-inhibitor of this enzyme superfamily. We discuss recent developments in the biological and biochemical actions of more complex vanadium derivatives, including decavanadate and in particular the growing number of oxidovanadium compounds with organic ligands. Pre-clinical studies involving these compounds are discussed in the anti-diabetic and anti-cancer contexts. Although in many cases PTP inhibition has been implicated, it is also clear that many such compounds have further biochemical effects in cells. There also remain concerns surrounding off-target toxicities and long-term use of vanadium compounds in vivo in humans, hindering their progress through clinical trials. Despite these current misgivings, interest in these chemicals continues and many believe they could still have therapeutic potential. If so, we argue that this field would benefit from greater focus on improving the delivery and tissue targeting of vanadium compounds in order to minimize off-target toxicities. This may then harness their full therapeutic potential.

Efficacy of topical tacrolimus 0.1% in active plaque morphea: randomized, double-blind, emollient-controlled pilot study.

NARCIS (Netherlands)

Kroft, Ilse; Groeneveld, T.J.; Seyger, M.M.B.; Jong, E.M.G.J. de

2009-01-01

BACKGROUND: Tacrolimus, a calcineurin inhibitor, is an immunomodulating and anti-inflammatory drug that inhibits T-cell activation and production of cytokines. The elevated level of cytokines in morphea causes fibroblast proliferation and subsequent overproduction of collagen. Theoretically,

VEGFR tyrosine kinase inhibitor II (VRI) induced vascular insufficiency in zebrafish as a model for studying vascular toxicity and vascular preservation

International Nuclear Information System (INIS)

Li, Shang; Dang, Yuan Ye; Oi Lam Che, Ginny; Kwan, Yiu Wa; Chan, Shun Wan; Leung, George Pak Heng; Lee, Simon Ming Yuen; Hoi, Maggie Pui Man

2014-01-01

In ischemic disorders such as chronic wounds and myocardial ischemia, there is inadequate tissue perfusion due to vascular insufficiency. Besides, it has been observed that prolonged use of anti-angiogenic agents in cancer therapy produces cardiovascular toxicity caused by impaired vessel integrity and regeneration. In the present study, we used VEGFR tyrosine kinase inhibitor II (VRI) to chemically induce vascular insufficiency in zebrafish in vivo and human umbilical vein endothelial cells (HUVEC) in vitro to further study the mechanisms of vascular morphogenesis in these pathological conditions. We also explored the possibility of treating vascular insufficiency by enhancing vascular regeneration and repair with pharmacological intervention. We observed that pretreatment of VRI induced blood vessel loss in developing zebrafish by inhibiting angiogenesis and increasing endothelial cell apoptosis, accompanied by down-regulation of kdr, kdrl and flt-1 genes expression. The VRI-induced blood vessel loss in zebrafish could be restored by post-treatment of calycosin, a cardiovascular protective isoflavone. Similarly, VRI induced cytotoxicity and apoptosis in HUVEC which could be rescued by calycosin post-treatment. Further investigation of the underlying mechanisms showed that the PI3K/AKT/Bad cell survival pathway was a main contributor of the vascular regenerative effect of calycosin. These findings indicated that the cardiovascular toxicity in anti-angiogenic therapy was mainly caused by insufficient endothelial cell survival, suggesting its essential role in vascular integrity, repair and regeneration. In addition, we showed that VRI-induced blood vessel loss in zebrafish represented a simple and effective in vivo model for studying vascular insufficiency and evaluating cancer drug vascular toxicities. - Highlights: • In vivo VRI model • Rescue effects of calycosin • Calycosin EC survival pathways

CaZF, a plant transcription factor functions through and parallel to HOG and calcineurin pathways in Saccharomyces cerevisiae to provide osmotolerance.

Directory of Open Access Journals (Sweden)

Deepti Jain

Full Text Available Salt-sensitive yeast mutants were deployed to characterize a gene encoding a C2H2 zinc finger protein (CaZF that is differentially expressed in a drought-tolerant variety of chickpea (Cicer arietinum and provides salinity-tolerance in transgenic tobacco. In Saccharomyces cerevisiae most of the cellular responses to hyper-osmotic stress is regulated by two interconnected pathways involving high osmolarity glycerol mitogen-activated protein kinase (Hog1p and Calcineurin (CAN, a Ca(2+/calmodulin-regulated protein phosphatase 2B. In this study, we report that heterologous expression of CaZF provides osmotolerance in S. cerevisiae through Hog1p and Calcineurin dependent as well as independent pathways. CaZF partially suppresses salt-hypersensitive phenotypes of hog1, can and hog1can mutants and in conjunction, stimulates HOG and CAN pathway genes with subsequent accumulation of glycerol in absence of Hog1p and CAN. CaZF directly binds to stress response element (STRE to activate STRE-containing promoter in yeast. Transactivation and salt tolerance assays of CaZF deletion mutants showed that other than the transactivation domain a C-terminal domain composed of acidic and basic amino acids is also required for its function. Altogether, results from this study suggests that CaZF is a potential plant salt-tolerance determinant and also provide evidence that in budding yeast expression of HOG and CAN pathway genes can be stimulated in absence of their regulatory enzymes to provide osmotolerance.

Recent Natural Corrosion Inhibitors for Mild Steel: An Overview

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Marko Chigondo

2016-01-01

Full Text Available Traditionally, reduction of corrosion has been managed by various methods including cathodic protection, process control, reduction of the metal impurity content, and application of surface treatment techniques, as well as incorporation of suitable alloys. However, the use of corrosion inhibitors has proven to be the easiest and cheapest method for corrosion protection and prevention in acidic media. These inhibitors slow down the corrosion rate and thus prevent monetary losses due to metallic corrosion on industrial vessels, equipment, or surfaces. Inorganic and organic inhibitors are toxic and costly and thus recent focus has been turned to develop environmentally benign methods for corrosion retardation. Many researchers have recently focused on corrosion prevention methods using green inhibitors for mild steel in acidic solutions to mimic industrial processes. This paper provides an overview of types of corrosion, corrosion process, and mainly recent work done on the application of natural plant extracts as corrosion inhibitors for mild steel.

Curcumin derivatives as HIV-1 protease inhibitors

Energy Technology Data Exchange (ETDEWEB)

Sui, Z.; Li, J.; Craik, C.S.; Ortiz de Montellano, P.R. [Univ. of California, San Francisco, CA (United States)

1993-12-31

Curcumin, a non-toxic natural compound from Curcuma longa, has been found to be an HIV-1 protease inhibitor. Some of its derivatives were synthesized and their inhibitory activity against the HIV-1 protease was tested. Curcumin analogues containing boron enhanced the inhibitory activity. At least of the the synthesized compounds irreversibly inhibits the HIV-1 protease.

Efficacy and safety of combinations of first-line topical treatments in chronic plaque psoriasis: a systematic literature review

NARCIS (Netherlands)

Hendriks, A.G.M.; Keijsers, R.R.M.C.; Jong, E.M.G.J. de; Seyger, M.M.B.; Kerkhof, P.C.M. van de

2013-01-01

Background Most psoriasis patients suffering from mild to moderate disease are treated with first-line topical treatments, including corticosteroids, vitamin D analogues, topical retinoids and calcineurin inhibitors. Although evidence-based guidelines on combinations are lacking, the majority of

Glomerular Filtration Rate Estimation in Renal and Non-Renal Solid Organ Transplantation

DEFF Research Database (Denmark)

Hornum, Mads; Feldt-Rasmussen, Bo

2017-01-01

Following transplantation (TX) of both renal and non-renal organs, a large proportion of patients have renal dysfunction. There are multiple causes for this. Chronic nephrotoxicity and high doses of calcineurin inhibitors are important factors. Preoperative and perioperative factors like hyperten......Following transplantation (TX) of both renal and non-renal organs, a large proportion of patients have renal dysfunction. There are multiple causes for this. Chronic nephrotoxicity and high doses of calcineurin inhibitors are important factors. Preoperative and perioperative factors like...... hypertension, hypotension, drugs and infections may play a causative role as well. Organ-specific causes include hepatorenal syndrome, cirrhosis, low cardiac function, low respiratory function and diabetes developed both before and after TX. It is important to be able to perform precise and valid measurements...... rate methods for use in renal and non-renal TX....

PD-1 checkpoint inhibition: Toxicities and management.

Science.gov (United States)

Hahn, Andrew W; Gill, David M; Agarwal, Neeraj; Maughan, Benjamin L

2017-12-01

With the recent approval of 5 PD-1/PD-L1 inhibitors for a number of malignancies, PD-1 axis inhibition is drastically changing the treatment landscape of immunotherapy in cancer. As PD-1/PD-L1 are involved in peripheral immune tolerance, inhibition of this immune checkpoint has led to novel immune-related adverse events including colitis, hepatitis, pneumonitis, rash, and endocrinopathies among many others. In this seminar, we will analyze the incidence of immune-related adverse events for nivolumab, pembrolizumab, atezolizumab, durvalumab, and avelumab. Then, we will discuss the specific management of the most common immune-mediated adverse events including colitis, hepatitis, pneumonitis, rash, endocrinopathies, nephritis, and neurologic toxicities. Immune-related adverse events are frequently treated with immunosuppressive medication such as steroids and mycofenolate mofetil. There are specific immune-related adverse events which are frequently seen by the treating oncologist from checkpoint inhibitors. It is essential to understand the recommended treatment options to minimize toxicity and mortality from this important class of anti-neoplastic therapies. Copyright © 2017 Elsevier Inc. All rights reserved.

Organophosphorus insecticides: Toxic effects and bioanalytical tests for evaluating toxicity during degradation processes

Directory of Open Access Journals (Sweden)

Čolović Mirjana B.

2013-01-01

Full Text Available Organophosphorus insecticides have been the most applied group of insecticides for the last two decades. Their main toxic effects are related to irreversible inactivation of acetylcholinesterase (AChE. Actually, they covalently bind to serine OH group in the enzyme active site forming phosphorylated enzyme that cannot hydrolyze acetylcholine. Organophosphorus insecticides in the environment undergo the natural degradation pathway including mainly homogeneous and heterogeneous hydrolysis (especially at high pH generating non-inhibiting products. Additionally, thio organophosphates are easily oxidized by naturally present oxidants and UV light, forming more toxic and stable oxons. Thus, oxidative degradation procedures, generally referred as advanced oxidation processes (AOP, have been applied for their efficient removal from contaminated waters. The most applied bioassays to monitor the organophosphate toxicity i.e. the detoxification degree during AOP are Vibrio fischeri and AChE bioassays. Vibrio fischeri toxicity test exploits bioluminescence as the measure of luciferase activity of this marine bacterium, whereas AChE bioassay is based on AChE activity inhibition. Both bioanalytical techniques are rapid (several minutes, simple, sensitive and reproducible. Vibrio fischeri test seems to be a versatile indicator of toxic compounds generated in AOP for organophosphorus insecticides degradation. However, detection of neurotoxic AChE inhibitors, which can be formed in AOP of some organophosphates, requires AChE bioassays. Therefore, AChE toxicity test is more appropriate for monitoring the degradation processes of thio organophosphates, because more toxic oxo organophosphates might be formed and overlooked by Vibrio fischeri bioluminescence inhibition. In addition, during organophosphates removal by AOP, compounds with strong genotoxic potential may be formed, which cannot be detected by standard toxicity tests. For this reason, determination of

Glucocorticoids and Polyamine Inhibitors Synergize to Kill Human Leukemic CEM Cells1

Science.gov (United States)

Miller, Aaron L; Johnson, Betty H; Medh, Rheem D; Townsend, Courtney M; Thompson, E Brad

2002-01-01

Abstract Glucocorticoids are well-known apoptotic agents in certain classes of lymphoid cell malignancies. Reduction of intracellular polyamine levels by use of inhibitors that block polyamine synthesis slows or inhibits growth of many cells in vitro. Several such inhibitors have shown efficacy in clinical trials, though the toxicity of some compounds has limited their usefulness. We have tested the effects of combinations of the glucocorticoid dexamethasone (Dex) and two polyamine inhibitors, difluoromethylornithine (DFMO) and methyl glyoxal bis guanylhydrazone (MGBG), on the clonal line of human acute lymphoblastic leukemia cells, CEM-C7-14. Dex alone kills these cells, though only after a delay of at least 24 hours. We also evaluated a partially glucocorticoid-resistant c-Myc-expressing CEM-C7-14 clone. We show that Dex downregulates ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine synthesis. Pretreatment with the ODC inhibitor DFMO, followed by addition of Dex, enhances steroid-evoked kill slightly. The combination of pretreatment with sublethal concentrations of both DFMO and the inhibitor of S-adenosylmethionine decarboxylase, MGBG, followed by addition of Dex, results in strong synergistic cell kill. Both the rapidity and extent of cell kill are enhanced compared to the effects of Dex alone. These results suggest that use of such combinations in vivo may result in apoptosis of malignant cells with lower overall toxicity. PMID:11922393

Toxicity to cotton boll weevil Anthonomus grandis of a trypsin inhibitor from chickpea seeds.

Science.gov (United States)

de P G Gomes, Angélica; Dias, Simoni C; Bloch, Carlos; Melo, Francislete R; Furtado, José R; Monnerat, Rose G; Grossi-de-Sá, Maria F; Franco, Octávio L

2005-02-01

Cotton (Gossypium hirsutum L.) is an important agricultural commodity, which is attacked by several pests such as the cotton boll weevil Anthonomus grandis. Adult A. grandis feed on fruits and leaf petioles, reducing drastically the crop production. The predominance of boll weevil digestive serine proteinases has motivated inhibitor screenings in order to discover new ones with the capability to reduce the digestion process. The present study describes a novel proteinase inhibitor from chickpea seeds (Cicer arietinum L.) and its effects against A. grandis. This inhibitor, named CaTI, was purified by using affinity Red-Sepharose Cl-6B chromatography, followed by reversed-phase HPLC (Vydac C18-TP). SDS-PAGE and MALDI-TOF analyses, showed a unique monomeric protein with a mass of 12,877 Da. Purified CaTI showed significant inhibitory activity against larval cotton boll weevil serine proteinases (78%) and against bovine pancreatic trypsin (73%), when analyzed by fluorimetric assays. Although the molecular mass of CaTI corresponded to alpha-amylase/trypsin bifunctional inhibitors masses, no inhibitory activity against insect and mammalian alpha-amylases was observed. In order to observe CaTI in vivo effects, an inhibitor rich fraction was added to an artificial diet at different concentrations. At 1.5% (w/w), CaTI caused severe development delay, several deformities and a mortality rate of approximately 45%. These results suggested that CaTI could be useful in the production of transgenic cotton plants with enhanced resistance toward cotton boll weevil.

Everolimus: a proliferation signal inhibitor with clinical applications in organ transplantation, oncology, and cardiology.

Science.gov (United States)

Gabardi, Steven; Baroletti, Steven A

2010-10-01

Everolimus, a proliferation signal inhibitor in the mammalian target of rapamycin (mTOR) drug class, has many clinical applications, including in organ transplantation, oncology, and cardiology. It currently has United States Food and Drug Administration (FDA) approval for prophylaxis against rejection in de novo renal transplant recipients, treatment of renal cell carcinoma, and use as a drug-eluting stent. To review the pharmacology, pharmacokinetics, efficacy, and safety of everolimus, we performed a search of the MEDLINE database (January 1997-April 2010) for all English-language articles of in vitro and in vivo studies that evaluated everolimus, as well as abstracts from recent scientific meetings and the manufacturer. In transplantation, everolimus demonstrates immunosuppressive properties and has been used to prevent acute rejection in cardiac, liver, lung, and renal transplant recipients. It appears that this agent may be potent enough to allow for the minimization or removal of calcineurin inhibitors in the long-term management of renal transplant recipients. In oncology, everolimus has been proven effective for the management of treatment-resistant renal cell carcinoma. In cardiology, everolimus is available as a drug-coated stent and is used in percutaneous coronary interventions for prevention of restenosis. In transplant recipients and patients with renal cell carcinoma, everolimus appears to have an extensive adverse-event profile. The pharmacologic properties of everolimus differentiate this agent from other drugs used in these clinical areas, and its pharmacokinetic properties differentiate it from sirolimus.

Novel dual small-molecule HIV inhibitors: scaffolds and discovery strategies.

Science.gov (United States)

Song, Anran; Yu, Haiqing; Wang, Changyuan; Zhu, Xingqi; Liu, Kexin; Ma, Xiaodong

2015-01-01

Searching for safe and effective treatments for HIV infection is still a great challenge worldwide in spite of the 27 marketed anti-HIV drugs and the powerful highly active antiretroviral therapy (HAART). As a promising prospect for generation of new HIV therapy drugs, multiple ligands (MDLs) were greatly focused on recently due to their lower toxicity, simplified dosing and patient adherence than single-target drugs. Till now, by disrupting two active sites or steps of HIV replications, a number of HIV dual inhibitors, such as CD4-gssucap120 inhibitors, CXCR4-gp20 inhibitors, RT-CXCR4 inhibitors, RT-protease inhibitors, RT-integrase inhibitors, and RTassociated functions inhibitors have been identified. Generally, these dual inhibitors were discovered mainly through screening approaches and design strategies. Of these compounds, the molecules bearing small skeletons exhibited strong anti-HIV activity and aroused great attention recently. Reviewing the progress of the dual small-molecule HIV inhibitors from the point of view of their scaffolds and discovery strategies will provide valuable information for producing more effective anti-HIV drugs. In this regard, novel dual small-molecule HIV inhibitors were illustrated, and their discovery paradigms as the major contents were also summarized in this manuscript.

Improved Pulse Wave Velocity and Renal Function in Individualized Calcineurin Inhibitor Treatment by Immunomonitoring: The Randomized Controlled Calcineurin Inhibitor-Sparing Trial.

Science.gov (United States)

Sommerer, Claudia; Brocke, Janina; Bruckner, Thomas; Schaier, Matthias; Morath, Christian; Meuer, Stefan; Zeier, Martin; Giese, Thomas

2018-03-01

A new immune monitoring tool which assesses the expression of nuclear factor of activated T cells (NFAT)-regulated genes measures the functional effects of cyclosporine A. This is the first prospective randomized controlled study to compare standard pharmacokinetic monitoring by cyclosporine trough levels to NFAT-regulated gene expression (NFAT-RE). Expression of the NFAT-regulated genes was determined by qRT-PCR at cyclosporine trough and peak level. Cardiovascular risk was assessed by change of pulse wave velocity from baseline to month 6. Clinical follow-up was 12 months. In total, 55 stable kidney allograft recipients were enrolled. Mean baseline residual NFAT-RE was 13.1 ± 9.1%. Patients in the NFAT-RE group showed a significant decline in pulse wave velocity from baseline to month 6 versus the standard group (-1.7 ± 2.0 m/s vs 0.4 ± 1.4 m/s, P function was significantly better with NFAT-RE versus standard monitoring (Nankivell glomerular filtration rate: 68.5 ± 17.4 mL/min vs 57.2 ± 19.0 mL/min; P = 0.009). NFAT-RE as translational immune monitoring tool proved efficacious and safe in individualizing cyclosporine therapy, with the opportunity to reduce the cardiovascular risk and improve long-term renal allograft function.

Immune-checkpoint inhibitors in the era of precision medicine: What radiologists should know

Energy Technology Data Exchange (ETDEWEB)

Braschi-Amirfarzan, Marta; Tirumani, Sree Harsha; Hodi, Frank Stephan Jr; Nishno, Mizuki [Dept. of Radiology, Brigham and Women' s Hospital and Dana Farber Cancer Institute, Boston (United States)

2017-01-15

Over the past five years immune-checkpoint inhibitors have dramatically changed the therapeutic landscape of advanced solid and hematologic malignancies. The currently approved immune-checkpoint inhibitors include antibodies to cytotoxic T-lymphocyte antigen-4, programmed cell death (PD-1), and programmed cell death ligand (PD-L1 and PD-L2). Response to immune-checkpoint inhibitors is evaluated on imaging using the immune-related response criteria. Activation of immune system results in a unique toxicity profile termed immune-related adverse events. This article will review the molecular mechanism, clinical applications, imaging of immune-related response patterns and adverse events associated with immune-checkpoint inhibitors.

Immune-checkpoint inhibitors in the era of precision medicine: What radiologists should know

International Nuclear Information System (INIS)

Braschi-Amirfarzan, Marta; Tirumani, Sree Harsha; Hodi, Frank Stephan Jr; Nishno, Mizuki

2017-01-01

Over the past five years immune-checkpoint inhibitors have dramatically changed the therapeutic landscape of advanced solid and hematologic malignancies. The currently approved immune-checkpoint inhibitors include antibodies to cytotoxic T-lymphocyte antigen-4, programmed cell death (PD-1), and programmed cell death ligand (PD-L1 and PD-L2). Response to immune-checkpoint inhibitors is evaluated on imaging using the immune-related response criteria. Activation of immune system results in a unique toxicity profile termed immune-related adverse events. This article will review the molecular mechanism, clinical applications, imaging of immune-related response patterns and adverse events associated with immune-checkpoint inhibitors

Janus kinase inhibitors: jackpot or potluck?

Directory of Open Access Journals (Sweden)

Pavithran Keechilat

2012-06-01

Full Text Available The reports of a unique mutation in the Janus kinase-2 gene (JAK2 in polycythemia vera by several independent groups in 2005 quickly spurred the development of the Janus kinase inhibitors. In one of the great victories of translational research in recent times, the first smallmolecule Janus kinase inhibitor ruxolitinib entered a phase I trial in 2007. With the approval of ruxolitinib by the US Federal Drug Administration in November 2011 for high-risk and intermediate-2 risk myelofibrosis, a change in paradigm has occurred in the management of a subset of myeloproliferative neoplasms (MPN: primary myelofibrosis, post-polycythemia vera myelofibrosis, and post-essential thrombocythemia myelofibrosis. Whereas the current evidence for ruxolitinib only covers high-risk and intermediate-2 risk myelofibrosis, inhibitors with greater potency are likely to offer better disease control and survival advantage in patients belonging to these categories, and possibly to the low-risk and intermediate-1 risk categories of MPN as well. But use of the Janus kinase inhibitors also probably has certain disadvantages, such as toxicity, resistance, withdrawal phenomenon, non-reversal of histology, and an implausible goal of disease clone eradication, some of which could offset the gains. In spite of this, Janus kinase inhibitors are here to stay, and for use in more than just myeloproliferative neoplasms.

Identification of fermentation inhibitors in wood hydrolyzates and removal of inhibitors by ion exchange and liquid-liquid extraction

Science.gov (United States)

Luo, Caidian

1998-12-01

Common methods employed in the ethanol production from biomass consist of chemical or enzymatic degradation of biomass into sugars and then fermentation of sugars into ethanol or other chemicals. However, some degradation products severely inhibit the fermentation processes and substantially reduce the efficiency of ethanol production. How to remove inhibitors from the reaction product mixture and increase the production efficiency are critical in the commercialization of any processes of energy from biomass. The present study has investigated anion exchange and liquid-liquid extraction as potential methods for inhibitor removal. An analytical method has been developed to identify the fermentation inhibitors in a hydrolyzate. The majority of inhibitors present in hybrid poplar hydrolyzate have positively been identified. Ion exchange with weak basic Dowex-MWA-1 resin has been proved to be an effective mean to remove fermentation inhibitors from hybrid poplar hydrolyzate and significantly increase the fermentation productivity. Extraction with n-butanol might be a preferred way to remove inhibitors from wood hydrolyzates and improve the fermentability of sugars in the hydrolyzates. n-Butanol also removes some glucose, mannose and xylose from the hydrolyzate. Inhibitor identification reveals that lignin and sugar degradation compounds including both aromatic and aliphatic aldehydes and carboxylic acids formed in hydrolysis, plus fatty acids and other components from wood extractives are major fermentation inhibitors in Sacchromyces cerevisiae fermentation. There are 35 components identified as fermentation inhibitors. Among them, 4-hydroxy benzoic acid, 3,4-dihydroxy benzoic acid, syringic acid, syringaldehyde, and ferulic acid are among the most abundant aromatic inhibitors in hybrid poplar hydrolyzate. The conversion of aldehyde groups into carboxylic acid groups in the nitric acid catalyzed hydrolysis reduces the toxicity of the hydrolyzate. A wide spectrum of

Calcineurin Dysregulation Underlies Spinal Cord Injury-Induced K+ Channel Dysfunction in DRG Neurons.

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Zemel, Benjamin M; Muqeem, Tanziyah; Brown, Eric V; Goulão, Miguel; Urban, Mark W; Tymanskyj, Stephen R; Lepore, Angelo C; Covarrubias, Manuel

2017-08-23

Dysfunction of the fast-inactivating Kv3.4 potassium current in dorsal root ganglion (DRG) neurons contributes to the hyperexcitability associated with persistent pain induced by spinal cord injury (SCI). However, the underlying mechanism is not known. In light of our previous work demonstrating modulation of the Kv3.4 channel by phosphorylation, we investigated the role of the phosphatase calcineurin (CaN) using electrophysiological, molecular, and imaging approaches in adult female Sprague Dawley rats. Pharmacological inhibition of CaN in small-diameter DRG neurons slowed repolarization of the somatic action potential (AP) and attenuated the Kv3.4 current. Attenuated Kv3.4 currents also exhibited slowed inactivation. We observed similar effects on the recombinant Kv3.4 channel heterologously expressed in Chinese hamster ovary cells, supporting our findings in DRG neurons. Elucidating the molecular basis of these effects, mutation of four previously characterized serines within the Kv3.4 N-terminal inactivation domain eliminated the effects of CaN inhibition on the Kv3.4 current. SCI similarly induced concurrent Kv3.4 current attenuation and slowing of inactivation. Although there was little change in CaN expression and localization after injury, SCI induced upregulation of the native regulator of CaN 1 (RCAN1) in the DRG at the transcript and protein levels. Consistent with CaN inhibition resulting from RCAN1 upregulation, overexpression of RCAN1 in naive DRG neurons recapitulated the effects of pharmacological CaN inhibition on the Kv3.4 current and the AP. Overall, these results demonstrate a novel regulatory pathway that links CaN, RCAN1, and Kv3.4 in DRG neurons. Dysregulation of this pathway might underlie a peripheral mechanism of pain sensitization induced by SCI. SIGNIFICANCE STATEMENT Pain sensitization associated with spinal cord injury (SCI) involves poorly understood maladaptive modulation of neuronal excitability. Although central mechanisms have

Discovery of DNA Topoisomerase I Inhibitors with Low-Cytotoxicity Based on Virtual Screening from Natural Products

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Lan-Ting Xin

2017-07-01

Full Text Available Currently, DNA topoisomerase I (Topo I inhibitors constitute a family of antitumor agents with demonstrated clinical effects on human malignancies. However, the clinical uses of these agents have been greatly limited due to their severe toxic effects. Therefore, it is urgent to find and develop novel low toxic Topo I inhibitors. In recent years, during our ongoing research on natural antitumor products, a collection of low cytotoxic or non-cytotoxic compounds with various structures were identified from marine invertebrates, plants, and their symbiotic microorganisms. In the present study, new Topo I inhibitors were discovered from low cytotoxic and non-cytotoxic natural products by virtual screening with docking simulations in combination with bioassay test. In total, eight potent Topo I inhibitors were found from 138 low cytotoxic or non-cytotoxic compounds from coral-derived fungi and plants. All of these Topo I inhibitors demonstrated activities against Topo I-mediated relaxation of supercoiled DNA at the concentrations of 5–100 µM. Notably, the flavonoids showed higher Topo I inhibitory activities than other compounds. These newly discovered Topo I inhibitors exhibited structurally diverse and could be considered as a good starting point for the development of new antitumor lead compounds.

Immune checkpoint inhibitors and targeted therapies for metastatic melanoma: A network meta-analysis.

Science.gov (United States)

Pasquali, Sandro; Chiarion-Sileni, Vanna; Rossi, Carlo Riccardo; Mocellin, Simone

2017-03-01

Immune checkpoint inhibitors and targeted therapies, two new class of drugs for treatment of metastatic melanoma, have not been compared in randomized controlled trials (RCT). We quantitatively summarized the evidence and compared immune and targeted therapies in terms of both efficacy and toxicity. A comprehensive search for RCTs of immune checkpoint inhibitors and targeted therapies was conducted to August 2016. Using a network meta-analysis approach, treatments were compared with each other and ranked based on their effectiveness (as measured by the impact on progression-free survival [PFS]) and acceptability (the inverse of high grade toxicity). Twelve RCTs enrolling 6207 patients were included. Network meta-analysis generated 15 comparisons. Combined BRAF and MEK inhibitors were associated with longer PFS as compared to anti-CTLA4 (HR: 0.22; 95% confidence interval [CI]: 0.12-0.41) and anti-PD1 antibodies alone (HR: 0.38; CI: 0.20-0.72). However, anti-PD1 monoclonal antibodies were less toxic than anti-CTLA4 monoclonal antibodies (RR: 0.65; CI: 0.40-0.78) and their combination significantly increased toxicity compared to either single agent anti-CTLA4 (RR: 2.06; CI: 1.45-2.93) or anti-PD1 monoclonal antibodies (RR: 3.67; CI: 2.27-5.96). Consistently, ranking analysis suggested that the combination of targeted therapies is the most effective strategy, whereas single agent anti-PD1 antibodies have the best acceptability. The GRADE level of evidence quality for these findings was moderate to low. The simultaneous inhibition of BRAF and MEK appears the most effective treatment for melanomas harboring BRAF V600 mutation, although anti-PD1 antibodies appear to be less toxic. Further research is needed to increase the quality of evidence. Copyright © 2017 Elsevier Ltd. All rights reserved.

An overview of topical treatment for atopic eczema | Motswaledi ...

African Journals Online (AJOL)

... on the elbows and knees in younger children, and the cubital and popliteal fossae in older children and adults. Treatment modalities include emollients, topical corticosteroids, calcineurin inhibitors, phototherapy and immunosuppressive therapy. This article provides a brief overview of topical treatments for atopic eczema.

Use of TNF-inhibitors and ustekinumab for psoriasis during pregnancy

DEFF Research Database (Denmark)

Lund, Tamara; Thomsen, Simon Francis

2017-01-01

From 2002 to 2016 a total of seven women with severe refractory psoriasis were exposed to the TNF-inhibitors infliximab and adalimumab or to the IL12/23 inhibitor ustekinumab during one or more pregnancies. Maternal, fetal or teratogenic toxicity were not detected during pregnancy and puerperium....... All pregnancies were uneventful and resulted in delivery of 10 healthy children in total, one of the women is due February 2017. Postpartum, five of the women were lactating, but none of the women or newborns developed adverse reactions. Data on safety of treatment during breastfeeding are sparse...

Acute Oncology Care: A narrative review of the acute management of neutropenic sepsis and immune-related toxicities of checkpoint inhibitors.

Science.gov (United States)

Knight, Thomas; Ahn, Shin; Rice, Terry W; Cooksley, Tim

2017-11-01

Cancer care has become increasingly specialized and advances in therapy have resulted in a larger number of patients receiving care. There has been a significant increase in the number of patients presenting with cancer related emergencies including treatment toxicities and those directly related to the malignancy. Suspected neutropenic sepsis is an acute medical emergency and empirical antibiotic therapy should be administered immediately. The goal of empirical therapy is to cover the most likely pathogens that will cause life-threatening infections in neutropenic patients. Patients with febrile neutropenia are a heterogeneous group with only a minority of treated patients developing significant medical complications. Outpatient management of low risk febrile neutropenia patients identified by the MASCC score is a safe and effective strategy. Immunotherapy with "checkpoint inhibitors" has significantly improved outcomes for patients with metastatic melanoma and evidence of benefit in a wide range of malignancies is developing. Despite these clinical benefits a number of immune related adverse events have been recognised which can affect virtually all organ systems and are potentially fatal. The timing of the onset of the adverse events is dependent on the organ system affected and unlike anti-neoplastic therapy can be delayed significantly after initiation or completion of therapy. The field of Acute Oncology is changing rapidly. Alongside, the traditional challenge of neutropenic sepsis there are many emerging toxicities. Further research into the optimal management, strategies and pathways of acutely unwell patients with cancer is required. Copyright © 2017 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

Identification of Inhibitors in Lignocellulosic Slurries and Determination of Their Effect on Hydrocarbon-Producing Microorganisms

Directory of Open Access Journals (Sweden)

Shihui Yang

2018-04-01

Full Text Available The aim of this work was to identify inhibitors in pretreated lignocellulosic slurries, evaluate high-throughput screening strategies, and investigate the impact of inhibitors on potential hydrocarbon-producing microorganisms. Compounds present in slurries that could inhibit microbial growth were identified through a detailed analysis of saccharified slurries by applying a combination of approaches of high-performance liquid chromatography, GC-MS, LC-DAD-MS, and ICP-MS. Several high-throughput assays were then evaluated to generate toxicity profiles. Our results demonstrated that Bioscreen C was useful for analyzing bacterial toxicity but not for yeast. AlamarBlue reduction assay can be a useful high-throughput assay for both bacterial and yeast strains as long as medium components do not interfere with fluorescence measurements. In addition, this work identified two major inhibitors (furfural and ammonium acetate for three potential hydrocarbon-producing bacterial species that include Escherichia coli, Cupriavidus necator, and Rhodococcus opacus PD630, which are also the primary inhibitors for ethanologens. This study was strived to establish a pipeline to quantify inhibitory compounds in biomass slurries and high-throughput approaches to investigate the effect of inhibitors on microbial biocatalysts, which can be applied for various biomass slurries or hydrolyzates generated through different pretreatment and enzymatic hydrolysis processes or different microbial candidates.

Fatal acute pulmonary injury associated with everolimus.

Science.gov (United States)

Depuydt, Pieter; Nollet, Joke; Benoit, Dominique; Praet, Marleen; Caes, Frank

2012-03-01

To report a case of fatal alveolar hemorrhage associated with the use of everolimus in a patient who underwent a solid organ transplant. In a 71-year-old cardiac transplant patient, cyclosporine was replaced with everolimus because of worsening renal function. Over the following weeks, the patient developed nonproductive cough and increasing dyspnea. His condition deteriorated to acute respiratory failure with hemoptysis, requiring hospital admission. Bilateral patchy alveolar infiltrates were apparent on chest X-ray and computed tomography. Cardiac failure was ruled out and empiric antimicrobial therapy was initiated. Additional extensive workup could not document opportunistic infection. Everolimus was discontinued and high-dose corticosteroid therapy was initiated. Despite this, the patient required invasive mechanical ventilation and died because of refractory massive hemoptysis. Autopsy revealed diffuse alveolar hemorrhage. Everolimus is a mammalian target of rapamycin inhibitor approved for use as an immunosuppressant and antineoplastic agent. Its main advantage over calcineurin inhibitors (tacrolimus and cyclosporine) is a distinct safety profile. Although it has become clear that everolimus induces pulmonary toxicity more frequently than initially thought, most published cases thus far represented mild and reversible disease, and none was fatal. Here, we report a case of pulmonary toxicity developing over weeks following the introduction of everolimus, in which a fatal outcome could not be prevented by drug withdrawal and corticosteroid treatment. The association of everolimus and this syndrome was probable according to the Naranjo probability scale. This case indicates that with the increasing use of everolimus, clinicians should be aware of the rare, but life-threatening manifestation of pulmonary toxicity.

Novel endogenous angiogenesis inhibitors and their therapeutic potential.

Science.gov (United States)

Rao, Nithya; Lee, Yu Fei; Ge, Ruowen

2015-10-01

Angiogenesis, the formation of new blood vessels from the pre-existing vasculature is essential for embryonic development and tissue homeostasis. It also plays critical roles in diseases such as cancer and retinopathy. A delicate balance between pro- and anti-angiogenic factors ensures normal physiological homeostasis. Endogenous angiogenesis inhibitors are proteins or protein fragments that are formed in the body and have the ability to limit angiogenesis. Many endogenous angiogenesis inhibitors have been discovered, and the list continues to grow. Endogenous protein/peptide inhibitors are relatively less toxic, better tolerated and have a lower risk of drug resistance, which makes them attractive as drug candidates. In this review, we highlight ten novel endogenous protein angiogenesis inhibitors discovered within the last five years, including ISM1, FKBPL, CHIP, ARHGAP18, MMRN2, SOCS3, TAp73, ZNF24, GPR56 and JWA. Although some of these proteins have been well characterized for other biological functions, we focus on their new and specific roles in angiogenesis inhibition and discuss their potential for therapeutic application.

Monoamine Oxidase B Inhibitors in Parkinson's Disease.

Science.gov (United States)

Dezsi, Livia; Vecsei, Laszlo

2017-01-01

Parkinson's disease (PD) is a neurodegenerative disorder with a prevalence increasing with age. Oxidative stress and glutamate toxicity are involved in its pathomechanism. There are still many unmet needs of PD patients, including the alleviation of motor fluctuations and dyskinesias, and the development of therapies with neuroprotective potential. To give an overview of the pharmacological properties, the efficacy and safety of the monoamine oxidase B (MAO-B) inhibitors in the treatment of PD, with special focus on the results of randomized clinical trials. A literature search was conducted in PubMed for 'PD treatment', 'MAO-B inhibitors', 'selegiline', 'rasagiline', 'safinamide' and 'clinical trials' with 'MAO-B inhibitors' in 'Parkinson' disease'. MAO-B inhibitors have a favorable pharmacokinetic profile, improve the dopamine deficient state and may have neuroprotective properties. Safinamide exhibits an anti-glutamatergic effect as well. When applied as monotherapy, MAO-B inhibitors provide a modest, but significant improvement of motor function and delay the need for levodopa. Rasagiline and safinamide were proven safe and effective when added to a dopamine agonist in early PD. As add-on to levodopa, MAO-B inhibitors significantly reduced off-time and were comparable in efficacy to COMT inhibitors. Improvements were achieved as regards certain non-motor symptoms as well. Due to the efficacy shown in clinical trials and their favorable side-effect profile, MAO-B inhibitors are valuable drugs in the treatment of PD. They are recommended as monotherapy in the early stages of the disease and as add-on therapy to levodopa in advanced PD. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

CYP 2E1 mutant mice are resistant to DDC-induced enhancement of MPTP toxicity.

Science.gov (United States)

Viaggi, C; Vaglini, F; Pardini, C; Sgadò, P; Caramelli, A; Corsini, G U

2007-01-01

In order to reach a deeper insight into the mechanism of diethyldithiocarbamate (DDC)-induced enhancement of MPTP toxicity in mice, we showed that CYP450 (2E1) inhibitors, such as diallyl sulfide (DAS) or phenylethylisothiocyanate (PIC), also potentiate the selective DA neuron degeneration in C57/bl mice. Furthermore we showed that CYP 2E1 is present in the brain and in the basal ganglia of mice (Vaglini et al., 2004). However, because DAS and PIC are not selective CYP 2E1 inhibitors and in order to provide direct evidence for CYP 2E1 involvement in the enhancement of MPTP toxicity, CYP 2E1 knockout mice (GONZ) and wild type animals (SVI) of the same genetic background were treated with MPTP or the combined DDC + MPTP treatment. In CYP 2E1 knockout mice, DDC pretreatment completely fails to enhance MPTP toxicity, although enhancement of MPTP toxicity was regularly present in the SVI control animals. The immunohistochemical study confirms our results and suggests that CYP 2E1 may have a detoxifying role.

Wound complications and surgical events in de novo heart transplant patients treated with everolimus

DEFF Research Database (Denmark)

Rashidi, Mitra; Esmaily, Sorosh; Fiane, Arnt E

2016-01-01

OBJECTIVES: The use of mammalian target of rapamycin (mTOR) inhibitors have been limited by adverse events (AE), including delayed wound healing. We retrospectively reviewed all AE and serious AE (SAE) in The Scandinavian heart transplant (HTx) everolimus (EVE) de novo trial with early calcineurin...

Prominent increased calcineurin immunoreactivity in the superior temporal gyrus in schizophrenia: A postmortem study.

Science.gov (United States)

Wada, Akira; Kunii, Yasuto; Matsumoto, Jyunya; Hino, Mizuki; Yang, Qiaohui; Niwa, Shin-Ichi; Yabe, Hirooki

2017-01-01

Many neuroimaging studies have demonstrated structural changes in the superior temporal gyrus (STG) in patients with schizophrenia. Several postmortem studies have reported on the pathogenesis of schizophrenia, but few reports have investigated alterations in molecules in the STG. In addition, several studies have suggested that calcineurin (CaN) inadequacy may be a risk factor for schizophrenia, but no reports about CaN expression in the STG in schizophrenia have been published. We compared the density of CaN-immunoreactive (CaN-IR) neurons in the STG from 11 patients with schizophrenia with that of 11 sex- and age-matched controls. We used immunohistochemical analysis with rabbit polyclonal antibodies against human CaN. In the STG, the density of CaN-IR neurons in layers II - VI in the group with schizophrenia was significantly higher than that in the control group. Our results confirmed pathological changes in the STG in patients with schizophrenia, suggesting that alterations in the CaN pathway play a role in the pathogenesis of schizophrenia. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Comparing the therapeutic efficiency of aminoguanidine and 3-aminobenzamide in lung and intestine toxicity caused by nitrogen mustard in rats

International Nuclear Information System (INIS)

Yaren, H.; Korkmaz, A.; Kunak, Z. I.; Uysal, B.; Topal, T.; Kurt, B; Kenar, L.

2009-01-01

Nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) and peroxynitrite are responsible for sulfur mustard (SM) induced toxicity. Since endogenous production of peroxynitrite is known to lead to poly(ADP-ribose) polymerase (PARP) activation and sometimes ultimately cell death, in this study, it was aimed to compare the therapeutic efficiencies of aminoguanidine (iNOS inhibitor) and 3 aminobenzamide (PARP inhibitor) in lung and intestine toxicity caused by nitrogen mustard in rats. A total of 40 male Sprague-Dawley rats were divided into 4 groups. Group 1 served as control and given 2 ml saline, three groups received single dose of mechlorethamine (MEC) (3.5 mg/kg subcutaneously) with the same time intervals. Group 2 received MEC only, group 3 received selective iNOS inhibitor aminoguanidine (AG) (100 mg/kg i.p.) and, group 4 received PARP inhibitor 3 aminobenzamide (3-AB) (20 mg/kg i.p.). MEC injection resulted in severe lung toxicity with strong interstitial and alveolar edema, hemorrhage, emphysematous changes, Mild inflammatory cell infiltration and septal thickening. MEC injection also caused mucosal thinning, mild inflammatory cell infiltration, ischemic changes and multifocal, superficial ulcerations (erosions) in small intestine. In AG group, interstitial and alveolar edema, hemorrhage slightly reduced in lung comparing to MEC group. Inflammatory cell infiltration was minimal, septal thickening was similar to MEC group at densely edematous and hemorrhagical areas. In 3 AB group, edematous and hemorrhagic areas were very small, inflammatory cell infiltration was minimal and there were no densly densely edematous and hemorrhagical areas in lung. The results were better than AB group. In intestine, results of AG group were better than MEC group but worse than 3 AB group. These results suggest that both iNOS and PARP inhibitors are effective but PARP inhibitors may be more promising for treatment of SM induced early lung and intestinal toxicity.(author)

Phenolic Amides Are Potent Inhibitors of De Novo Nucleotide Biosynthesis.

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Pisithkul, Tippapha; Jacobson, Tyler B; O'Brien, Thomas J; Stevenson, David M; Amador-Noguez, Daniel

2015-09-01

An outstanding challenge toward efficient production of biofuels and value-added chemicals from plant biomass is the impact that lignocellulose-derived inhibitors have on microbial fermentations. Elucidating the mechanisms that underlie their toxicity is critical for developing strategies to overcome them. Here, using Escherichia coli as a model system, we investigated the metabolic effects and toxicity mechanisms of feruloyl amide and coumaroyl amide, the predominant phenolic compounds in ammonia-pretreated biomass hydrolysates. Using metabolomics, isotope tracers, and biochemical assays, we showed that these two phenolic amides act as potent and fast-acting inhibitors of purine and pyrimidine biosynthetic pathways. Feruloyl or coumaroyl amide exposure leads to (i) a rapid buildup of 5-phosphoribosyl-1-pyrophosphate (PRPP), a key precursor in nucleotide biosynthesis, (ii) a rapid decrease in the levels of pyrimidine biosynthetic intermediates, and (iii) a long-term generalized decrease in nucleotide and deoxynucleotide levels. Tracer experiments using (13)C-labeled sugars and [(15)N]ammonia demonstrated that carbon and nitrogen fluxes into nucleotides and deoxynucleotides are inhibited by these phenolic amides. We found that these effects are mediated via direct inhibition of glutamine amidotransferases that participate in nucleotide biosynthetic pathways. In particular, feruloyl amide is a competitive inhibitor of glutamine PRPP amidotransferase (PurF), which catalyzes the first committed step in de novo purine biosynthesis. Finally, external nucleoside supplementation prevents phenolic amide-mediated growth inhibition by allowing nucleotide biosynthesis via salvage pathways. The results presented here will help in the development of strategies to overcome toxicity of phenolic compounds and facilitate engineering of more efficient microbial producers of biofuels and chemicals. Copyright © 2015, Pisithkul et al.

Phenolic Amides Are Potent Inhibitors of De Novo Nucleotide Biosynthesis

Science.gov (United States)

Pisithkul, Tippapha; Jacobson, Tyler B.; O'Brien, Thomas J.; Stevenson, David M.

2015-01-01

An outstanding challenge toward efficient production of biofuels and value-added chemicals from plant biomass is the impact that lignocellulose-derived inhibitors have on microbial fermentations. Elucidating the mechanisms that underlie their toxicity is critical for developing strategies to overcome them. Here, using Escherichia coli as a model system, we investigated the metabolic effects and toxicity mechanisms of feruloyl amide and coumaroyl amide, the predominant phenolic compounds in ammonia-pretreated biomass hydrolysates. Using metabolomics, isotope tracers, and biochemical assays, we showed that these two phenolic amides act as potent and fast-acting inhibitors of purine and pyrimidine biosynthetic pathways. Feruloyl or coumaroyl amide exposure leads to (i) a rapid buildup of 5-phosphoribosyl-1-pyrophosphate (PRPP), a key precursor in nucleotide biosynthesis, (ii) a rapid decrease in the levels of pyrimidine biosynthetic intermediates, and (iii) a long-term generalized decrease in nucleotide and deoxynucleotide levels. Tracer experiments using 13C-labeled sugars and [15N]ammonia demonstrated that carbon and nitrogen fluxes into nucleotides and deoxynucleotides are inhibited by these phenolic amides. We found that these effects are mediated via direct inhibition of glutamine amidotransferases that participate in nucleotide biosynthetic pathways. In particular, feruloyl amide is a competitive inhibitor of glutamine PRPP amidotransferase (PurF), which catalyzes the first committed step in de novo purine biosynthesis. Finally, external nucleoside supplementation prevents phenolic amide-mediated growth inhibition by allowing nucleotide biosynthesis via salvage pathways. The results presented here will help in the development of strategies to overcome toxicity of phenolic compounds and facilitate engineering of more efficient microbial producers of biofuels and chemicals. PMID:26070680

The evolution of the matrix metalloproteinase inhibitor drug discovery program at abbott laboratories.

Science.gov (United States)

Wada, Carol K

2004-01-01

Matrix metalloproteinases (MMPs) have been implicated in several pathologies. At Abbott Laboratories, the matrix metalloproteinases inhibitor drug discovery program has focused on the discovery of a potent, selective, orally bioavailable MMP inhibitor for the treatment of cancer. The program evolved from early succinate-based inhibitors to utilizing in-house technology such as SAR by NMR to develop a novel class of biaryl hydroxamate MMP inhibitors. The metabolic instability of the biaryl hydroxamates led to the discovery of a new class of N-formylhydroxylamine (retrohydroxamate) biaryl ethers, exemplified by ABT-770 (16). Toxicity issues with this pre-clinical candidate led to the discovery of another novel class of retrohydroxamate MMP inhibitors, the phenoxyphenyl sulfones such as ABT-518 (19j). ABT-518 is a potent, orally bioavailable, selective inhibitor of MMP-2 and 9 over MMP-1 that has been evaluated in Phase I clinical trials in cancer patients.

Analysis of Drug Development Paradigms for Immune Checkpoint Inhibitors.

Science.gov (United States)

Jardim, Denis L; de Melo Gagliato, Débora; Giles, Francis J; Kurzrock, Razelle

2018-04-15

Immune checkpoint inhibitors have unique toxicities and response kinetics compared with cytotoxic and gene-targeted anticancer agents. We investigated the impact of innovative/accelerated immunotherapy drug development/approval models on the accuracy of safety and efficacy assessments by searching the FDA website. Initial phase I trials for each agent were reviewed and safety and efficacy data compared with that found in later trials leading to regulatory approvals of the same agents. As of June 2017, the FDA approved six checkpoint inhibitors for a variety of cancer types. All checkpoint inhibitors received a priority review status and access to at least two additional FDA special access programs, more often breakthrough therapy designation and accelerated approval. Median clinical development time (investigational new drug application to approval) was 60.77 months [avelumab had the shortest timeline (52.33 months)]. Response rates during early phase I trials (median = 16%) are higher than for phase I trials of other agents (with the exception of gene-targeted agents tested with a biomarker). Doses approved were usually not identical to doses recommended on phase I trials. Approximately 50% of types of immune-related and 43% of types of clinically relevant toxicities from later trials were identified in early-phase trials. Even so, treatment-related mortality remains exceedingly low in later studies (0.33% of patients). In conclusion, efficacy and safety of immune checkpoint inhibitors appear to be reasonably predicted from the dose-finding portion of phase I trials, indicating that the fast-track development of these agents is safe and justified. Clin Cancer Res; 24(8); 1785-94. ©2017 AACR . ©2017 American Association for Cancer Research.

A novel class of small molecule inhibitors of HDAC6.

Science.gov (United States)

Inks, Elizabeth S; Josey, Benjamin J; Jesinkey, Sean R; Chou, C James

2012-02-17

Histone deacetylases (HDACs) are a family of enzymes that play significant roles in numerous biological processes and diseases. HDACs are best known for their repressive influence on gene transcription through histone deacetylation. Mapping of nonhistone acetylated proteins and acetylation-modifying enzymes involved in various cellular pathways has shown protein acetylation/deacetylation also plays key roles in a variety of cellular processes including RNA splicing, nuclear transport, and cytoskeletal remodeling. Studies of HDACs have accelerated due to the availability of small molecule HDAC inhibitors, most of which contain a canonical hydroxamic acid or benzamide that chelates the metal catalytic site. To increase the pool of unique and novel HDAC inhibitor pharmacophores, a pharmacological active compound screen was performed. Several unique HDAC inhibitor pharmacophores were identified in vitro. One class of novel HDAC inhibitors, with a central naphthoquinone structure, displayed a selective inhibition profile against HDAC6. Here we present the results of a unique class of HDAC6 inhibitors identified using this compound library screen. In addition, we demonstrated that treatment of human acute myeloid leukemia cell line MV4-11 with the selective HDAC6 inhibitors decreases levels of mutant FLT-3 and constitutively active STAT5 and attenuates Erk phosphorylation, all of which are associated with the inhibitor's selective toxicity against leukemia.

Treatment of intractable interstitial lung injury with alemtuzumab after lung transplantation

DEFF Research Database (Denmark)

Kohno, M; Perch, M; Andersen, E

2011-01-01

of acute rejection, worsened within 2 weeks, despite high-dose steroids, change of calcineurin inhibitor, and plasmapheresis. Within a few days after a single, 10-mg, intravenous dose of alemtuzumab, the patient's health improved markedly. She has remained stable for 4 months on a standard, ambulatory...

Adverse effects of ultraviolet irradiation in atopic dermatitis.

NARCIS (Netherlands)

ten Berge, O.

2010-01-01

The overall aim of this thesis was to evaluate adverse effects of ultraviolet irradiation (UV) in atopic dermatitis (AD). We focused on the two important adverse effects of UV: photosensitivity and skin cancer risk associated with calcineurin inhibitor treatment. In chapter 2 and 3 we found that

Azidoblebbistatin, a photoreactive myosin inhibitor

Science.gov (United States)

Képiró, Miklós; Várkuti, Boglárka H.; Bodor, Andrea; Hegyi, György; Drahos, László; Kovács, Mihály; Málnási-Csizmadia, András

2012-01-01

Photoreactive compounds are important tools in life sciences that allow precisely timed covalent crosslinking of ligands and targets. Using a unique technique we have synthesized azidoblebbistatin, which is a derivative of blebbistatin, the most widely used myosin inhibitor. Without UV irradiation azidoblebbistatin exhibits identical inhibitory properties to those of blebbistatin. Using UV irradiation, azidoblebbistatin can be covalently crosslinked to myosin, which greatly enhances its in vitro and in vivo effectiveness. Photo-crosslinking also eliminates limitations associated with the relatively low myosin affinity and water solubility of blebbistatin. The wavelength used for photo-crosslinking is not toxic for cells and tissues, which confers a great advantage in in vivo tests. Because the crosslink results in an irreversible association of the inhibitor to myosin and the irradiation eliminates the residual activity of unbound inhibitor molecules, azidoblebbistatin has a great potential to become a highly effective tool in both structural studies of actomyosin contractility and the investigation of cellular and physiological functions of myosin II. We used azidoblebbistatin to identify previously unknown low-affinity targets of the inhibitor (EC50 ≥ 50 μM) in Dictyostelium discoideum, while the strongest interactant was found to be myosin II (EC50 = 5 μM). Our results demonstrate that azidoblebbistatin, and potentially other azidated drugs, can become highly useful tools for the identification of strong- and weak-binding cellular targets and the determination of the apparent binding affinities in in vivo conditions. PMID:22647605

Epithelial tissue hyperplasia induced by the RAF inhibitor PF-04880594 is attenuated by a clinically well-tolerated dose of the MEK inhibitor PD-0325901.

Science.gov (United States)

Torti, Vince R; Wojciechowicz, Donald; Hu, Wenyue; John-Baptiste, Annette; Evering, Winston; Troche, Gabriel; Marroquin, Lisa D; Smeal, Tod; Yamazaki, Shinji; Palmer, Cynthia L; Burns-Naas, Leigh Ann; Bagrodia, Shubha

2012-10-01

Clinical trials of selective RAF inhibitors in patients with melanoma tumors harboring activated BRAFV600E have produced very promising results, and a RAF inhibitor has been approved for treatment of advanced melanoma. However, about a third of patients developed resectable skin tumors during the course of trials. This is likely related to observations that RAF inhibitors activate extracellular signal-regulated kinase (ERK) signaling, stimulate proliferation, and induce epithelial hyperplasia in preclinical models. Because these findings raise safety concerns about RAF inhibitor development, we further investigated the underlying mechanisms. We showed that the RAF inhibitor PF-04880594 induces ERK phosphorylation and RAF dimerization in those epithelial tissues that undergo hyperplasia. Hyperplasia and ERK hyperphosphorylation are prevented by treatment with the mitogen-activated protein/extracellular signal-regulated kinase (MEK) inhibitor PD-0325901 at exposures that extrapolate to clinically well-tolerated doses. To facilitate mechanistic and toxicologic studies, we developed a three-dimensional cell culture model of epithelial layering that recapitulated the RAF inhibitor-induced hyperplasia and reversal by MEK inhibitor in vitro. We also showed that PF-04880594 stimulates production of the inflammatory cytokine interleukin 8 in HL-60 cells, suggesting a possible mechanism for the skin flushing observed in dogs. The complete inhibition of hyperplasia by MEK inhibitor in epithelial tissues does not seem to reduce RAF inhibitor efficacy and, in fact, allows doubling of the PF-04880594 dose without toxicity usually associated with such doses. These findings indicated that combination treatment with MEK inhibitors might greatly increase the safety and therapeutic index of RAF inhibitors for the treatment of melanoma and other cancers. ©2012 AACR.

Vulnerability to glutamate toxicity of dopaminergic neurons is dependent on endogenous dopamine and MAPK activation.

Science.gov (United States)

Izumi, Yasuhiko; Yamamoto, Noriyuki; Matsuo, Takaaki; Wakita, Seiko; Takeuchi, Hiroki; Kume, Toshiaki; Katsuki, Hiroshi; Sawada, Hideyuki; Akaike, Akinori

2009-07-01

Dopaminergic neurons are more vulnerable than other types of neurons in cases of Parkinson disease and ischemic brain disease. An increasing amount of evidence suggests that endogenous dopamine plays a role in the vulnerability of dopaminergic neurons. Although glutamate toxicity contributes to the pathogenesis of these disorders, the sensitivity of dopaminergic neurons to glutamate toxicity has not been clarified. In this study, we demonstrated that dopaminergic neurons were preferentially affected by glutamate toxicity in rat mesencephalic cultures. Glutamate toxicity in dopaminergic neurons was blocked by inhibiting extracellular signal-regulated kinase (ERK), c-jun N-terminal kinase, and p38 MAPK. Furthermore, depletion of dopamine by alpha-methyl-dl-p-tyrosine methyl ester (alpha-MT), an inhibitor of tyrosine hydroxylase (TH), protected dopaminergic neurons from the neurotoxicity. Exposure to glutamate facilitated phosphoryration of TH at Ser31 by ERK, which contributes to the increased TH activity. Inhibition of ERK had no additive effect on the protection offered by alpha-MT, whereas alpha-MT and c-jun N-terminal kinase or p38 MAPK inhibitors had additive effects and yielded full protection. These data suggest that endogenous dopamine is responsible for the vulnerability to glutamate toxicity of dopaminergic neurons and one of the mechanisms may be an enhancement of dopamine synthesis mediated by ERK.

Novel orally bioavailable EZH1/2 dual inhibitors with greater antitumor efficacy than an EZH2 selective inhibitor.

Science.gov (United States)

Honma, Daisuke; Kanno, Osamu; Watanabe, Jun; Kinoshita, Junzo; Hirasawa, Makoto; Nosaka, Emi; Shiroishi, Machiko; Takizawa, Takeshi; Yasumatsu, Isao; Horiuchi, Takao; Nakao, Akira; Suzuki, Keisuke; Yamasaki, Tomonori; Nakajima, Katsuyoshi; Hayakawa, Miho; Yamazaki, Takanori; Yadav, Ajay Singh; Adachi, Nobuaki

2017-10-01

Polycomb repressive complex 2 (PRC2) methylates histone H3 lysine 27 and represses gene expression to regulate cell proliferation and differentiation. Enhancer of zeste homolog 2 (EZH2) or its close homolog EZH1 functions as a catalytic subunit of PRC2, so there are two PRC2 complexes containing either EZH2 or EZH1. Tumorigenic functions of EZH2 and its synthetic lethality with some subunits of SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling complexes have been observed. However, little is known about the function of EZH1 in tumorigenesis. Herein, we developed novel, orally bioavailable EZH1/2 dual inhibitors that strongly and selectively inhibited methyltransferase activity of both EZH2 and EZH1. EZH1/2 dual inhibitors suppressed trimethylation of histone H3 lysine 27 in cells more than EZH2 selective inhibitors. They also showed greater antitumor efficacy than EZH2 selective inhibitor in vitro and in vivo against diffuse large B-cell lymphoma cells harboring gain-of-function mutation in EZH2. A hematological cancer panel assay indicated that EZH1/2 dual inhibitor has efficacy against some lymphomas, multiple myeloma, and leukemia with fusion genes such as MLL-AF9, MLL-AF4, and AML1-ETO. A solid cancer panel assay demonstrated that some cancer cell lines are sensitive to EZH1/2 dual inhibitor in vitro and in vivo. No clear correlation was detected between sensitivity to EZH1/2 dual inhibitor and SWI/SNF mutations, with a few exceptions. Severe toxicity was not seen in rats treated with EZH1/2 dual inhibitor for 14 days at drug levels higher than those used in the antitumor study. Our results indicate the possibility of EZH1/2 dual inhibitors for clinical applications. © 2017 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

Early Non-Immunological Post Transplant complications: A Single Center Experience

Directory of Open Access Journals (Sweden)

Jabur Wael

2008-01-01

Full Text Available To assess non-immunological complications affecting renal transplant patients in the first six months after transplantation in Al-Karama hospital, Baghdad, Iraq, we studied 68 patients (49 males, 19 females attending the clinic during the year 2006. Forty six (67% patients received kidneys from related and 22 (33% from unrelated donors. The patients revealed the following complications: post transplant hypertension in 28 (41% patient, infection (mostly bacterial in 27 (37%, new onset diabetes in 11 (16%, calcineurin inhibitor toxicity in 10 (14%, anemia in 8 (12%, surgical complications in 7 (10%, slow graft recovery in 4 (6%, cardiovascular complications in 3 (4%, and Kaposi sarcoma in 2 (2.9%.Transient hyperglycemia, hypertension, infection and diabetes mel-litus were the commonest early complications of renal transplantation. The incidence of complications is comparable to the average reported in the literature, especially in this region of the world.

Steroid-free immunosuppression after renal transplantation-long-term experience from a single centre

DEFF Research Database (Denmark)

El-Faramawi, Mohamad; Rohr, Nils; Jespersen, Bente

2006-01-01

BACKGROUND: A steroid-free immunosuppressive protocol may improve the general well-being of patients, but long-term renal graft survival has been a concern. METHODS: In a retrospective clinical study, 329 consecutive transplantations with renal grafts at our centre during the period 1995-2004, were......, for instance because of primary kidney disease or when calcineurin inhibitor toxicity was suspected. RESULTS: About 71% of the patients did not take steroids at all. Nevertheless, graft survival rates at 1, 5 and 7 years were 95, 77 and 72% for all grafts, including 27% living donor transplants and 27% second...... or subsequent grafts. Ten patients (3.2%) died with functioning grafts. Within the first year of transplantation there were 69 acute rejections in 63 patients (19%). Four cases (1.3%) of post-transplant lymphoproliferative disorder (PTLD) occurred with one graft loss and no deaths. Owing to a high PTLD rate...

Use of proteasome inhibitors in anticancer therapy

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Sara M. Schmitt

2011-10-01

Full Text Available The importance of the ubiquitin-proteasome pathway to cellular function has brought it to the forefront in the search for new anticancer therapies. The ubiquitin-proteasome pathway has proven promising in targeting various human cancers. The approval of the proteasome inhibitor bortezomib for clinical treatment of relapsed/refractory multiple myeloma and mantle cell lymphoma has validated the ubiquitin-proteasome as a rational target. Bortezomib has shown positive results in clinical use but some toxicity and side effects, as well as resistance, have been observed, indicating that further development of novel, less toxic drugs is necessary. Because less toxic drugs are necessary and drug development can be expensive and time-consuming, using existing drugs that can target the ubiquitin-proteasome pathway in new applications, such as cancer therapy, may be effective in expediting the regulatory process and bringing new drugs to the clinic. Toward this goal, previously approved drugs, such as disulfiram, as well as natural compounds found in common foods, such as green tea polyphenol (--EGCG and the flavonoid apigenin, have been investigated for their possible proteasome inhibitory and cell death inducing abilities. These compounds proved quite promising in preclinical studies and have now moved into clinical trials, with preliminary results that are encouraging. In addition to targeting the catalytic activity of the proteasome pathway, upstream regulators, such as the 19S regulatory cap, as well as E1, E2, and E3, are now being investigated as potential drug targets. This review outlines the development of novel proteasome inhibitors from preclinical to clinical studies, highlighting their abilities to inhibit the tumor proteasome and induce apoptosis in several human cancers.

Bowman-Birk inhibitor affects pathways associated with energy metabolism in Drosophila melanogaster

Science.gov (United States)

Bowman-Birk inhibitor (BBI) is toxic when fed to certain insects, including the fruit fly, Drosophila melanogaster. Dietary BBI has been demonstrated to slow growth and increase insect mortality by inhibiting the digestive enzymes trypsin and chymotrypsin, resulting in a reduced supply of amino acid...

Immunosuppressive treatment for nephrotic idiopathic membranous nephropathy: a meta-analysis based on Chinese adults.

Directory of Open Access Journals (Sweden)

Guoqiang Xie

Full Text Available Idiopathic membranous nephropathy (IMN is the most common pathological type for nephrotic syndrome in adults in western countries and China. The benefits and harms of immunosuppressive treatment in IMN remain controversial.To assess the efficacy and safety of different immunosuppressive agents in the treatment of nephrotic syndrome caused by IMN.PubMed, EMBASE, Cochrane Library and wanfang, weipu, qinghuatongfang, were searched for relevant studies published before December 2011. Reference lists of nephrology textbooks, review articles were checked. A meta-analysis of randomized controlled trials (RCTs meeting the criteria was performed using Review Manager.17 studies were included, involving 696 patients. Calcineurin inhibitors had a better effect when compared to alkylating agents, on complete remission (RR 1.61, 95% CI 1.13, to 2.30 P = 0.008, partial or complete remission (effective (CR/PR, RR 1.29, 95% CI 1.09 to 1.52 P = 0.003, and fewer side effects. Among calcineurin inhibitors, tacrolimus (TAC was shown statistical significance in inducing more remissions. When compared to cyclophosphamide (CTX, leflunomide (LET showed no beneficial effect, mycophenolate mofetil (MMF showed significant beneficial on effectiveness (CR/PR, RR: 1.41, 95% CI 1.16 to 1.72 P = 0.0006 but not significant on complete remission (CR, RR: 1.38, 95% CI 0.89 to 2.13 P = 0.15.This analysis based on Chinese adults and short duration RCTs suggested calcineurin inhibitors, especially TAC, were more effective in proteinuria reduction in IMN with acceptable side effects. Long duration RCTs were needed to confirm the long-term effects of those agents in nephrotic IMN.

JAK inhibitors for the treatment of myeloproliferative neoplasms and other disorders [version 1; referees: 2 approved

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William Vainchenker

2018-01-01

Full Text Available JAK inhibitors have been developed following the discovery of the JAK2V617F in 2005 as the driver mutation of the majority of non-BCR-ABL1 myeloproliferative neoplasms (MPNs. Subsequently, the search for JAK2 inhibitors continued with the discovery that the other driver mutations (CALR and MPL also exhibited persistent JAK2 activation. Several type I ATP-competitive JAK inhibitors with different specificities were assessed in clinical trials and exhibited minimal hematologic toxicity. Interestingly, these JAK inhibitors display potent anti-inflammatory activity. Thus, JAK inhibitors targeting preferentially JAK1 and JAK3 have been developed to treat inflammation, autoimmune diseases, and graft-versus-host disease. Ten years after the beginning of clinical trials, only two drugs have been approved by the US Food and Drug Administration: one JAK2/JAK1 inhibitor (ruxolitinib in intermediate-2 and high-risk myelofibrosis and hydroxyurea-resistant or -intolerant polycythemia vera and one JAK1/JAK3 inhibitor (tofacitinib in methotrexate-resistant rheumatoid arthritis. The non-approved compounds exhibited many off-target effects leading to neurological and gastrointestinal toxicities, as seen in clinical trials for MPNs. Ruxolitinib is a well-tolerated drug with mostly anti-inflammatory properties. Despite a weak effect on the cause of the disease itself in MPNs, it improves the clinical state of patients and increases survival in myelofibrosis. This limited effect is related to the fact that ruxolitinib, like the other type I JAK2 inhibitors, inhibits equally mutated and wild-type JAK2 (JAK2WT and also the JAK2 oncogenic activation. Thus, other approaches need to be developed and could be based on either (1 the development of new inhibitors specifically targeting JAK2V617F or (2 the combination of the actual JAK2 inhibitors with other therapies, in particular with molecules targeting pathways downstream of JAK2 activation or the stability of JAK2

Atopic dermatitis: tacrolimus vs. topical corticosteroid use | Langa ...

African Journals Online (AJOL)

Despite this, the US Food and Drug Administration (FDA) black box warning of possible malignancies has resulted in much debate among experts. The main focus of this article is to compare the safety and efficacy of topical corticosteroids to calcineurin inhibitors, particularly tacrolimus. Furthermore, the aim is to evaluate ...

The Pharmacogenetics of Tacrolimus in Corticosteroid-Sparse Pediatric and Adult Kidney Transplant Recipients

DEFF Research Database (Denmark)

Juul Madsen, Mads; Bergmann, Troels K; Brøsen, Kim

2017-01-01

INTRODUCTION: Tacrolimus is a calcineurin inhibitor used as an immunosuppressant drug in solid organ transplantation, and is mainly metabolized by cytochrome P450 (CYP) 3A4 and CYP3A5. Studies have shown an association between the CYP3A5 genotype and tacrolimus dose-adjusted trough concentrations...

Toxicity of palmitoyl glycerol to mice: depression of thyroid function

International Nuclear Information System (INIS)

Trumbo, P.R.; Meuten, D.J.; King, M.W.; Tove, S.B.

1987-01-01

Mice given propylthiouracil, a thyroid inhibitor, and fed a diet containing a nontoxic level of rac-1(3)-palmitoyl glycerol showed the hypothermia and mortality expected for a toxic dose, but did not show these signs when linoleate or oleate was added to the diet. Loss of radioiodine from the whole animal and thyroid gland was slower when mice were fed the toxic palmitoyl glycerol diet than when fed the same diet containing 4% safflower oil. However, mice fed the two diets did not differ in the extent of the incorporation of radioiodine, and essentially all was bound to protein in each case. Follicular thyroid cells from mice fed the potentially toxic diet that contained unsaturated fat were normal in appearance. Conversely, cells from mice fed the toxic diet were smaller and more densely stained, showing evidence of glycoprotein inside the cell. These findings show that the thyroid gland is affected by the palmitoyl glycerol diet. However, the thyroid is not the only organ affected, because giving either thyroxine or triiodothyronine had no effect on the toxicity of palmitoyl glycerol

Lung inflammation caused by inhaled toxicants: a review

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Wong J

2016-06-01

Full Text Available John Wong, Bruce E Magun, Lisa J Wood School of Nursing, MGH Institute of Health Professions, Boston, MA, USA Abstract: Exposure of the lungs to airborne toxicants from different sources in the environment may lead to acute and chronic pulmonary or even systemic inflammation. Cigarette smoke is the leading cause of chronic obstructive pulmonary disease, although wood smoke in urban areas of underdeveloped countries is now recognized as a leading cause of respiratory disease. Mycotoxins from fungal spores pose an occupational risk for respiratory illness and also present a health hazard to those living in damp buildings. Microscopic airborne particulates of asbestos and silica (from building materials and those of heavy metals (from paint are additional sources of indoor air pollution that contributes to respiratory illness and is known to cause respiratory illness in experimental animals. Ricin in aerosolized form is a potential bioweapon that is extremely toxic yet relatively easy to produce. Although the aforementioned agents belong to different classes of toxic chemicals, their pathogenicity is similar. They induce the recruitment and activation of macrophages, activation of mitogen-activated protein kinases, inhibition of protein synthesis, and production of interleukin-1 beta. Targeting either macrophages (using nanoparticles or the production of interleukin-1 beta (using inhibitors against protein kinases, NOD-like receptor protein-3, or P2X7 may potentially be employed to treat these types of lung inflammation without affecting the natural immune response to bacterial infections. Keywords: cigarette, mycotoxin, trichothecene, ricin, inflammasome, macrophage, inhibitors

A role for CaV1 and calcineurin signaling in depolarization-induced changes in neuronal DNA methylation.

Science.gov (United States)

Hannon, Eilis; Chand, Annisa N; Evans, Mark D; Wong, Chloe C Y; Grubb, Matthew S; Mill, Jonathan

2015-07-01

Direct manipulations of neuronal activity have been shown to induce changes in DNA methylation (DNAm), although little is known about the cellular signaling pathways involved. Using reduced representation bisulfite sequencing, we identify DNAm changes associated with moderate chronic depolarization in dissociated rat hippocampal cultures. Consistent with previous findings, these changes occurred primarily in the vicinity of loci implicated in neuronal function, being enriched in intergenic regions and underrepresented in CpG-rich promoter regulatory regions. We subsequently used 2 pharmacological interventions (nifedipine and FK-506) to test whether the identified changes depended on 2 interrelated signaling pathways known to mediate multiple forms of neuronal plasticity. Both pharmacological manipulations had notable effects on the extent and magnitude of depolarization-induced DNAm changes indicating that a high proportion of activity-induced changes are likely to be mediated by calcium entry through L-type Ca V 1 channels and/or downstream signaling via the calcium-dependent phosphatase calcineurin.

A role for CaV1 and calcineurin signaling in depolarization-induced changes in neuronal DNA methylation

Directory of Open Access Journals (Sweden)

Eilis Hannon

2015-07-01

Full Text Available Direct manipulations of neuronal activity have been shown to induce changes in DNA methylation (DNAm, although little is known about the cellular signaling pathways involved. Using reduced representation bisulfite sequencing, we identify DNAm changes associated with moderate chronic depolarization in dissociated rat hippocampal cultures. Consistent with previous findings, these changes occurred primarily in the vicinity of loci implicated in neuronal function, being enriched in intergenic regions and underrepresented in CpG-rich promoter regulatory regions. We subsequently used 2 pharmacological interventions (nifedipine and FK-506 to test whether the identified changes depended on 2 interrelated signaling pathways known to mediate multiple forms of neuronal plasticity. Both pharmacological manipulations had notable effects on the extent and magnitude of depolarization-induced DNAm changes indicating that a high proportion of activity-induced changes are likely to be mediated by calcium entry through L-type CaV1 channels and/or downstream signaling via the calcium-dependent phosphatase calcineurin.

Cysteine as a non toxic corrosion inhibitor for copper alloys in conservation

DEFF Research Database (Denmark)

Gravgaard, Mari; van Lanschot, Jettie

2012-01-01

studies of colour changes in the corrosion products. The results obtained in this article demonstrate that cysteine could be a non-toxic alternative to BTA. Cysteine performed as well as BTA on pre-corroded coupons with bronze disease in high humidity and showed acceptable results during testing...

Lichen sclerosus er en forsømt sygdom

DEFF Research Database (Denmark)

Sander, Bente Braad; Damsgaard, Knud

2011-01-01

We present a small review of lichen sclerosus in women and an update on the newest knowledge, e.g. on calcineurin inhibitors as a choice of treatment. The goal is to put more focus on the disease in Denmark because it is so often diagnosed only with a great delay. We further emphasize...

Proteomic analysis of rat cerebral cortex following subchronic acrolein toxicity.

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Rashedinia, Marzieh; Lari, Parisa; Abnous, Khalil; Hosseinzadeh, Hossein

2013-10-01

Acrolein, a member of reactive α,β-unsaturated aldehydes, is a major environmental pollutant. Acrolein is also produced endogenously as a toxic by-product of lipid peroxidation. Because of high reactivity, acrolein may mediate oxidative damages to cells and tissues. It has been shown to be involved in a wide variety of pathological states including pulmonary, atherosclerosis and neurodegenerative diseases. In this study we employed proteomics approach to investigate the effects of subchronic oral exposures to 3mg/kg of acrolein on protein expression profile in the brain of rats. Moreover effects of acrolein on malondialdehyde (MDA) levels and reduced glutathione (GSH) content were investigated. Our results revealed that treatment with acrolein changed levels of several proteins in diverse physiological process including energy metabolism, cell communication and transport, response to stimulus and metabolic process. Interestingly, several differentially over-expressed proteins, including β-synuclein, enolase and calcineurin, are known to be associated with human neurodegenerative diseases. Changes in the levels of some proteins were confirmed by Western blot. Moreover, acrolein increases the level of MDA, as a lipid peroxidation biomarker and decreased GSH concentrations, as a non-enzyme antioxidant in the brain of acrolein treated rats. These findings suggested that acrolein induces the oxidative stress and lipid peroxidation in the brain, and so that may contribute to the pathophysiology of neurological disorders. Copyright © 2013 Elsevier Inc. All rights reserved.

Naturally occurring Vpr inhibitors from medicinal plants of Myanmar.

Science.gov (United States)

Win, Nwet Nwet; Ngwe, Hla; Abe, Ikuro; Morita, Hiroyuki

2017-10-01

Human immunodeficiency virus type-1 (HIV-1) is a lentiviral family member that encodes the retroviral Gag, Pol, and Env proteins, along with six additional accessory proteins, Tat, Rev, Vpu, Vif, Nef, and Vpr. The currently approved anti-HIV drugs target the Pol and Env encoded proteins. However, these drugs are only effective in reducing viral replication. Furthermore, the drugs' toxicities and the emergence of drug-resistant strains have become serious worldwide problems. Resistance eventually arises to all of the approved anti-HIV drugs, including the newly approved drugs that target HIV integrase (IN). Drug resistance likely emerges because of spontaneous mutations that occur during viral replication. Therefore, new drugs that effectively block other viral components must be developed to reduce the rate of resistance and suppress viral replication with little or no long-term toxicity. The accessory proteins may expand treatment options. Viral protein R (Vpr) is one of the promising drug targets among the HIV accessory proteins. However, the search for inhibitors continues in anti-HIV drug discovery. In this review, we summarize the naturally occurring compounds discovered from two Myanmar medicinal plants as well as their structure-activity relationships. A total of 49 secondary metabolites were isolated from Kaempferia pulchra rhizomes and Picrasama javanica bark, and the types of compounds were identified as isopimarane diterpenoids and picrasane quassinoids, respectively. Among the isolates, 7 diterpenoids and 15 quassinoids were found to be Vpr inhibitors lacking detectable toxicity, and their potencies varied according to their respective functionalities.

Effect of caffeine inhibitor in corrosion rate and microstructure of KS01 carbon steel and AISI 1045 at media sea water

International Nuclear Information System (INIS)

Sulistioso Giat S; Setyo Purwanto; Deswita; Ari Handayani; Berta Vidyananda

2013-01-01

Many synthetic materials are good inhibitors for the prevention of corrosion . Many inhibitors are toxic, because of the influence of these toxic properties, recently use organic materials as corrosion inhibitors, that are not hazardous and environmentally friendly. In this study caffeine compounds used as corrosion inhibitors. This compound could be used as corrosion inhibitor because of the existence of their chemical groups that containing free electron pair, that is nitrogen. Corrosion rate testing conducted in sea water medium taken from the Northern region of Indramayu with variations of the concentration of caffeine 0, 50, 100, 150, and 200 ppm to determine the optimum concentration of caffeine in corrosion rate of carbon steel AISI 1045 and KS01 that a widely used on the cooling system in the industry. Corrosion rate of KS-01 steel before used in inhibitor media is 25,07 mpy that less than corrosion rate of carbon steel AISI 1045, is 45,82 mpy . The results of this study indicate that caffeine is able to inhibit the corrosion rate of both of samples with optimum efficiency KS01 for 64.38%, and AISI 1045 of 66.63%. The optimum concentration of caffeine to inhibited AISI 1045 is 150 ppm and for KS01 is 100 ppm,. Beside that analysis of microstructure for both samples have done, for media before and after inhibitor addition. (author)

Tyrosine kinase inhibitors directed against the vascular endothelial growth factor receptor (VEGFR) have distinct cutaneous toxicity profiles: a meta-analysis and review of the literature.

Science.gov (United States)

Massey, Paul R; Okman, Jonathan S; Wilkerson, Julia; Cowen, Edward W

2015-06-01

Inhibition of the vascular endothelial growth factor receptor (VEGFR) with tyrosine kinase inhibitors (TKIs) is associated with cutaneous adverse effects that increase patient morbidity. Our objective was to examine the skin toxicity profile of anti-VEGFR TKIs and determine the changing incidence in clinical trials. PubMed was queried for phase II or III trials of anti-VEGFR TKIs between 2000 and 2013 involving ≥50 patients. Adverse events were abstracted, with results presented in both fixed and random effects models. Odds ratios (OR) and 95 % confidence intervals (CIs) were estimated for studies with at least two arms. Across 82 included studies, all grades rash (OR, 2.68; 95 % CI, 2.45-2.94), hand-foot skin reaction (HFSR) (OR, 2.70; 95 % CI, 2.43-3.00), and pruritus (OR, 1.25; 95 % CI, 1.12-1.39) were associated with anti-VEGFR TKIs. Vandetanib had the highest incidence of rash (41 %), while sorafenib was most commonly associated with HFSR (37 %) and pruritus (14 %). The incidence of HFSR from 2000 to 2013 showed an upward trend (r (2) = 0.042, p = 0.10) and in sunitinib therapy increased significantly (r (2) = 0.237, p = 0.04). The incidence of HFSR, rash, and pruritus varies considerably by drug. Our data suggest a continued need to address skin toxicities and improve reporting strategies.

Validation of the 2nd Generation Proteasome Inhibitor Oprozomib for Local Therapy of Pulmonary Fibrosis.

Directory of Open Access Journals (Sweden)

Nora Semren

Full Text Available Proteasome inhibition has been shown to prevent development of fibrosis in several organs including the lung. However, effects of proteasome inhibitors on lung fibrosis are controversial and cytotoxic side effects of the overall inhibition of proteasomal protein degradation cannot be excluded. Therefore, we hypothesized that local lung-specific application of a novel, selective proteasome inhibitor, oprozomib (OZ, provides antifibrotic effects without systemic toxicity in a mouse model of lung fibrosis. Oprozomib was first tested on the human alveolar epithelial cancer cell line A549 and in primary mouse alveolar epithelial type II cells regarding its cytotoxic effects on alveolar epithelial cells and compared to the FDA approved proteasome inhibitor bortezomib (BZ. OZ was less toxic than BZ and provided high selectivity for the chymotrypsin-like active site of the proteasome. In primary mouse lung fibroblasts, OZ showed significant anti-fibrotic effects, i.e. reduction of collagen I and α smooth muscle actin expression, in the absence of cytotoxicity. When applied locally into the lungs of healthy mice via instillation, OZ was well tolerated and effectively reduced proteasome activity in the lungs. In bleomycin challenged mice, however, locally applied OZ resulted in accelerated weight loss and increased mortality of treated mice. Further, OZ failed to reduce fibrosis in these mice. While upon systemic application OZ was well tolerated in healthy mice, it rather augmented instead of attenuated fibrotic remodelling of the lung in bleomycin challenged mice. To conclude, low toxicity and antifibrotic effects of OZ in pulmonary fibroblasts could not be confirmed for pulmonary fibrosis of bleomycin-treated mice. In light of these data, the use of proteasome inhibitors as therapeutic agents for the treatment of fibrotic lung diseases should thus be considered with caution.

Environmental toxicants, incidence of degenerative diseases, and therapies from the epigenetic point of view.

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Hodjat, Mahshid; Rahmani, Soheila; Khan, Fazlullah; Niaz, Kamal; Navaei-Nigjeh, Mona; Mohammadi Nejad, Solmaz; Abdollahi, Mohammad

2017-07-01

Epigenotoxicology is an emerging field of study that investigates the non-genotoxic epigenetic effects of environmental toxicants resulting in alteration of normal gene expression and disruption of cell function. Recent findings on the role of toxicant-induced epigenetic modifications in the development of degenerative diseases have opened up a promising research direction to explore epigenetic therapy approaches and related prognostic biomarkers. In this review, we presented comprehensive data on epigenetic alterations identified in various diseases, including cancer, autoimmune disorders, pulmonary conditions as well as cardiovascular, gastrointestinal and bone disease. Although data on abnormalities of DNA methylation and their role in the development of diseases are abundant, less is known about the impact of histone modifications and microRNA expressions. Further, we discussed the effects of selected common environmental toxicants on epigenetic modifications and their association with particular abnormalities. A number of different environmental toxicants have been identified for their role in aberrant DNA methylation, histone modifications, and microRNA expression. Such epigenetic effects were shown to be tissue-type specific and highly associated with the level and duration of exposure. Finally, we described present and future therapeutic strategies, including medicines and dietary compounds for combating the toxicant-induced epigenetic alterations. There are currently seven histone deacetylase inhibitors and two DNA methyltransferase inhibitors approved for clinical use and many other promising candidates are in preclinical and clinical testing. Dietary compounds are thought to be the effective and safe strategies for treating and prevention of epigenetic pathophysiological conditions. Still more concentrated epigenetic researches are required for evaluation of chemical toxicity and identifying the causal association between key epigenetic alteration and

Genomic mechanisms of stress tolerance for the industrial yeast Saccharomyces cerevisiae against the major chemical classes of inhibitors derived from lignocellulosic biomass conversion

Science.gov (United States)

Scientists at ARS developed tolerant industrial yeast that is able to reduce major chemical classes of inhibitors into less toxic or none toxic compounds while producing ethanol. Using genomic studies, we defined mechanisms of in situ detoxification involved in novel gene functions, vital cofactor r...

Hcm1 integrates signals from Cdk1 and calcineurin to control cell proliferation.

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Arsenault, Heather E; Roy, Jagoree; Mapa, Claudine E; Cyert, Martha S; Benanti, Jennifer A

2015-10-15

Cyclin-dependent kinase (Cdk1) orchestrates progression through the cell cycle by coordinating the activities of cell-cycle regulators. Although phosphatases that oppose Cdk1 are likely to be necessary to establish dynamic phosphorylation, specific phosphatases that target most Cdk1 substrates have not been identified. In budding yeast, the transcription factor Hcm1 activates expression of genes that regulate chromosome segregation and is critical for maintaining genome stability. Previously we found that Hcm1 activity and degradation are stimulated by Cdk1 phosphorylation of distinct clusters of sites. Here we show that, upon exposure to environmental stress, the phosphatase calcineurin inhibits Hcm1 by specifically removing activating phosphorylations and that this regulation is important for cells to delay proliferation when they encounter stress. Our work identifies a mechanism by which proliferative signals from Cdk1 are removed in response to stress and suggests that Hcm1 functions as a rheostat that integrates stimulatory and inhibitory signals to control cell proliferation. © 2015 Arsenault, Roy, et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Characterization of cholinesterases in Chironomus riparius and the effects of three herbicides on chlorpyrifos toxicity.

Science.gov (United States)

Pérez, Joanne; Monteiro, Marta S; Quintaneiro, Carla; Soares, Amadeu M V M; Loureiro, Susana

2013-11-15

In this study, the toxicities of four pesticides (the herbicides atrazine, terbuthylazine, metolachlor and the insecticide chlorpyrifos) previously detected in the Alqueva reservoir/dam (south of Portugal) were evaluated individually and in binary combinations of the herbicides and the insecticide using fourth-instar larvae of the aquatic midge Chironomus riparius. Chlorpyrifos induced toxicity to midges in all the 48 h toxicity bioassays performed. The swimming behaviour of the larvae was impaired, with EC50 values ranging from 0.15 to 0.17 μg/L. However, neither s-triazine (atrazine and terbuthylazine) herbicides nor metolachlor alone at concentrations up to 200 μg/L caused significant toxicity to C. riparius. When combined with both s-triazine herbicides, chlorpyrifos toxicity was enhanced by approximately 2-fold when tested in a binary mixture experimental setup, at the 50% effective concentration levels. To evaluate how chlorpyrifos toxicity was being increased, the cholinesterases (ChE) were characterized biochemically using different substrates and selective inhibitors. The results obtained suggested that the main enzyme present in this species is acetylcholinesterase (AChE) and therefore it was assayed upon C. riparius exposures to all pesticides individually and as binary mixtures. Although atrazine and terbuthylazine are not effective inhibitors of AChE, the potentiation of chlorpyrifos toxicity by the two s-triazine herbicides was associated with a potentiation in the inhibition of AChE in midges; both s-triazine herbicides at 200 μg/L increased the inhibition of the AChE activity by 7 and 8-fold, respectively. A strong correlation was observed between swimming behaviour disturbances of larvae and the inhibition of the AChE activity. In contrast, metolachlor did not affect chlorpyrifos toxicity at any of the concentrations tested. Therefore, the herbicides atrazine and terbuthylazine can act as synergists in the presence of chlorpyrifos, increasing

Larvicides and acetylcholinesterase inhibitors from Kalanchoe species

International Nuclear Information System (INIS)

Trevisan, Maria Teresa Salles; Bezerra, Maria Zeneide Barbosa; Santiago, Gilvandete Maria Pinheiro; Feitosa, Chistiane Mendes; Verpoorte, Robert; Gorlaeus Laboratories, Leiden; Braz Filho, Raimundo

2006-01-01

Acetylcholine esterase inhibitors are successfully used to treat the symptoms of Alzheimer's disease. Extracts of three Kalanchoe species (K. brasiliensis, K. pinnata and K. gastonis-bornieri) showed acetylcholine esterase inhibitory effects and a toxic effect on Aedes aegypti larvae. Here we describe the bioassay guided fractionation of extracts of the most active extracts (K. brasiliensis) which resulted in the isolation of an active mixture of three flavonoids: 8-methoxyquercetin, 3,7-di-O-rhamnopyranoside and 8-methoxykaempferol-3,7-di-O-rhamnopyranoside. On TLC these flavonoids showed an acetylcholine esterase inhibitory effect. (author)

The safety of antiangiogenic agents and PARP inhibitors in platinum-sensitive recurrent ovarian cancer.

Science.gov (United States)

Lorusso, Domenica; Fontanella, Caterina; Maltese, Giuseppa; Lepori, Stefano; Tripodi, Elisa; Bogani, Giorgio; Raspagliesi, Francesco

2017-06-01

Recurrence is a common event in endothelial ovarian cancer (EOC) patients, and the choice of the most appropriate treatment is driven by the platinum-free interval, molecular characteristics of the disease such as BRCA mutational status, previous treatments and toxicity. Areas covered: This review focuses on the main hematologic and non-hematologic toxicities correlated with the use of licensed antiangiogenic agents and PARP inhibitors in recurrent platinum-sensitive EOC, providing recommendations for their management. Expert opinion: The clinical research over the next years will be focused on a more precise characterization of molecular pathways underlying tumorigenesis of the five ovarian tumors, to improve the decision-making process in these rare diseases. For this purpose, new study designs and international collaborations will become mandatory. Immunotherapy, antiangiogenic agents and PARP inhibitors will be combined to build a treatment strategy algorithm which will allow patients to receive all the available treatment option, in the more appropriate sequence.

Research progress of hydroxychloroquine and autophagy inhibitors on cancer.

Science.gov (United States)

Shi, Ting-Ting; Yu, Xiao-Xu; Yan, Li-Jun; Xiao, Hong-Tao

2017-02-01

Hydroxychloroquine (HCQ), the analog of chloroquine, augments the effect of chemotherapies and radiotherapy on various tumors identified in the current clinical trials. Meanwhile, the toxicity of HCQ retinopathy raises concern worldwide. Thus, the potent autophagy inhibitors are urgently needed. A systematic review was related to 'hydroxychloroquine' or 'chloroquine' with 'clinical trials,' 'retinopathy' and 'new autophagy inhibitors.' This led to many cross-references involving HCQ, and these data have been incorporated into the following study. Many preclinical studies indicate that the combination of HCQ with chemotherapies or radiotherapies may enhance the effect of anticancer, providing base for launching cancer clinical trials involving HCQ. The new and more sensitive diagnostic techniques report a prevalence of HCQ retinopathy up to 7.5%. Lys05, SAR405, verteporfin, VATG-027, mefloquine and spautin-1 may be potent autophagy inhibitors. Additional mechanistic studies of HCQ in preclinical models are still required in order to answer these questions whether HCQ actually inhibits autophagy in non-selective tumors and whether the extent of inhibition would be sufficient to alter chemotherapy or radiotherapy sensitivity.

Isolation and characterization of Cupriavidus basilensis HMF14 for biological removal of inhibitors from lignocellulosic hydrolysatembt

NARCIS (Netherlands)

Wierckx, N.; Koopman, F.; Bandounas, L.; Winde, J.H.de; Ruijssenaars, H.J.

2010-01-01

The formation of toxic fermentation inhibitors such as furfural and 5-hydroxy-2-methylfurfural (HMF) during acid (pre-)treatment of lignocellulose, calls for the efficient removal of these compounds. Lignocellulosic hydrolysates can be efficiently detoxified biologically with microorganisms that

Multiscale numerical modeling of Ce3+-inhibitor release from novel corrosion protection coatings

International Nuclear Information System (INIS)

Trenado, Carlos; Wittmar, Matthias; Veith, Michael; Strauss, Daniel J; Rosero-Navarro, Nataly C; Aparicio, Mario; Durán, Alicia; Castro, Yolanda

2011-01-01

A novel hybrid sol–gel coating has recently been introduced as an alternative to high toxic chromate-based corrosion protection systems. In this paper, we propose a multiscale computational model to estimate the amount and time scale of inhibitor release of the active corrosion protection coating. Moreover, we study the release rate under the influence of parameters such as porosity and viscosity, which have recently been implicated in the stability of the coating. Numerical simulations obtained with the model predicted experimental release tests and recent findings on the compromise between inhibitor concentration and the stability of the coating

NABi, a novel β-sheet breaker, inhibits Aβ aggregation and neuronal toxicity: Therapeutic implications for Alzheimer's disease.

Science.gov (United States)

Jang, Ja-Young; Rhim, Hyangshuk; Kang, Seongman

2018-01-01

Amyloid beta (Aβ) aggregates are an important therapeutic target for Alzheimer's disease (AD), a fatal neurodegenerative disease. To date, AD still remains a big challenge due to no effective treatments. Based on the property that Aβ aggregates have the cross-β-structure, a common structural feature in amyloids, we systemically designed the Aβ-aggregation inhibitor that maintains Aβ-interacting ability but removes toxic part from SOD1 (superoxide dismutase 1)-G93A. We identified NABi (Natural Aβ Binder and Aβ-aggregation inhibitor) composed of β2-3 strands, a novel breaker of Aβ aggregation, which does not self-aggregate and has no cytotoxicity at all. The NABi blocks Aβ-fibril formation in vitro and in vivo and prevents neuronal cell death, a hallmark of AD pathogenesis. Such anti-amyloidogenic properties can provide novel strategies for treating AD. Furthermore, our study provides molecular insights into the design of amyloidogenic inhibitors to cure various neurodegenerative and amyloid-associated diseases, as NABi would regulate aggregation of other toxic β-sheet proteins other than Aβ. Copyright © 2017 Elsevier B.V. All rights reserved.

Mixture toxicity of three photosystem II inhibitors (atrazine, isoproturon, and diuron) toward photosynthesis of freshwater phytoplankton studied in outdoor mesocosms.

Science.gov (United States)

Knauert, Stefanie; Escher, Beate; Singer, Heinz; Hollender, Juliane; Knauer, Katja

2008-09-01

Mixture toxicity of three herbicides with the same mode of action was studied in a long-term outdoor mesocosm study. Photosynthetic activity of phytoplankton as the direct target site of the herbicides was chosen as physiological response parameter. The three photosystem II (PSII) inhibitors atrazine, isoproturon, and diuron were applied as 30% hazardous concentrations (HC30), which we derived from species sensitivity distributions calculated on the basis of EC50 growth inhibition data. The respective herbicide mixture comprised 1/3 of the HC30 of each herbicide. Short-term laboratory experiments revealed that the HC30 values corresponded to EC40 values when regarding photosynthetic activity as the response parameter. In the outdoor mesocosm experiment, effects of atrazine, isoproturon, diuron and their mixture on the photosynthetic activity of phytoplankton were investigated during a five-week period with constant exposure and a subsequent five-month postexposure period when the herbicides dissipated. The results demonstrated that mixture effects determined at the beginning of constant exposure can be described by concentration addition since the mixture elicited a phytotoxic effect comparable to the single herbicides. Declining effects on photosynthetic activity during the experiment might be explained by both a decrease in water herbicide concentrations and by the induction of community tolerance.

Test systems to identify reproductive toxicants.

Science.gov (United States)

Riecke, K; Stahlmann, R

2000-09-01

Experience with drugs and other xenobiotics indicates that both animal testing and epidemiological studies are necessary to provide adequate data for an estimation of risks that might be associated with exposure to a chemical substance. In this review, the pros and cons of test systems for reproductive toxicity are discussed. Usually, several studies are performed to cover the different phases of the reproductive cycle. In the preclinical development of drugs, the three so-called 'segment testing protocols' have been used for several decades now. More recently, new testing concepts have been accepted internationally which include more flexibility in implementation. Several examples of compounds with the potential for reproductive toxicity are presented in more detail in a discussion of some pitfalls of the tests for fertility (phthalates and fluoroquinolones), teratogenicity (acyclovir and protease inhibitors) and postnatal developmental toxicity (fluoroquinolones). In addition, important aspects of kinetics and metabolism as a prerequisite for a rational interpretation of results from toxicological studies are briefly discussed. In vitro assays are useful for supplementing the routinely used in vivo approaches or for studying an expected or defined effect, but they are not suitable for revealing an unknown effect of a chemical on the complex reproductive process.

Combination therapy for hepatitis C virus with heat-shock protein 90 inhibitor 17-AAG and proteasome inhibitor MG132.

Science.gov (United States)

Ujino, Saneyuki; Yamaguchi, Saori; Shimotohno, Kunitada; Takaku, Hiroshi

2010-03-09

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease. Here, we report a new and effective strategy for inhibiting HCV replication using an inhibitor of heat-shock protein 90, 17-AAG (17-allylamino-17demethoxygeldanamycin), and a proteasome inhibitor, MG132. To explore the virological basis of combination therapy, we analysed the effects of 17-AAG and MG132, singly and in combination on HCV replication in an HCV replicon cell system. In HCV replicon cells, HCV RNA replication was suppressed by 17-AAG in a dose-dependent manner. As shown in the present study, the 50% inhibitory concentration values were 0.82 nM for 17-AAG and 0.21 nM for MG132. Low concentrations of MG132 had strong synergistic inhibitory effects with low toxicity on HCV replicon cells. The results of this study suggest that the different effects and synergistic actions of 17-AAG and MG132 could provide a new therapeutic approach to HCV infection.

Identification of a Potent Phosphoinositide 3-Kinase Pan Inhibitor Displaying a Strategic Carboxylic Acid Group and Development of Its Prodrugs.

Science.gov (United States)

Pirali, Tracey; Ciraolo, Elisa; Aprile, Silvio; Massarotti, Alberto; Berndt, Alex; Griglio, Alessia; Serafini, Marta; Mercalli, Valentina; Landoni, Clarissa; Campa, Carlo Cosimo; Margaria, Jean Piero; Silva, Rangel L; Grosa, Giorgio; Sorba, Giovanni; Williams, Roger; Hirsch, Emilio; Tron, Gian Cesare

2017-09-21

Activation of the phosphoinositide 3-kinase (PI3K) pathway is a key signaling event in cancer, inflammation, and other proliferative diseases. PI3K inhibitors are already approved for some specific clinical indications, but their systemic on-target toxicity limits their larger use. In particular, whereas toxicity is tolerable in acute treatment of life-threatening diseases, this is less acceptable in chronic conditions. In the past, the strategy to overcome this drawback was to block selected isoforms mainly expressed in leukocytes, but redundancy within the PI3K family members challenges the effectiveness of this approach. On the other hand, decreasing exposure to selected target cells represents a so-far unexplored alternative to circumvent systemic toxicity. In this manuscript, we describe the generation of a library of triazolylquinolones and the development of the first prodrug pan-PI3K inhibitor. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Calcium regulates caveolin-1 expression at the transcriptional level

International Nuclear Information System (INIS)

Yang, Xiao-Yan; Huang, Cheng-Cheng; Kan, Qi-Ming; Li, Yan; Liu, Dan; Zhang, Xue-Cheng; Sato, Toshinori; Yamagata, Sadako; Yamagata, Tatsuya

2012-01-01

Highlights: ► Caveolin-1 expression is regulated by calcium signaling at the transcriptional level. ► An inhibitor of or siRNA to L-type calcium channel suppressed caveolin-1 expression. ► Cyclosporine A or an NFAT inhibitor markedly reduced caveolin-1 expression. ► Caveolin-1 regulation by calcium signaling is observed in several mouse cell lines. -- Abstract: Caveolin-1, an indispensable component of caveolae serving as a transformation suppressor protein, is highly expressed in poorly metastatic mouse osteosarcoma FBJ-S1 cells while highly metastatic FBJ-LL cells express low levels of caveolin-1. Calcium concentration is higher in FBJ-S1 cells than in FBJ-LL cells; therefore, we investigated the possibility that calcium signaling positively regulates caveolin-1 in mouse FBJ-S1 cells. When cells were treated with the calcium channel blocker nifedipine, cyclosporin A (a calcineurin inhibitor), or INCA-6 (a nuclear factor of activated T-cells [NFAT] inhibitor), caveolin-1 expression at the mRNA and protein levels decreased. RNA silencing of voltage-dependent L-type calcium channel subunit alpha-1C resulted in suppression of caveolin-1 expression. This novel caveolin-1 regulation pathway was also identified in mouse NIH 3T3 cells and Lewis lung carcinoma cells. These results indicate that caveolin-1 is positively regulated at the transcriptional level through a novel calcium signaling pathway mediated by L-type calcium channel/Ca 2+ /calcineurin/NFAT.

Antidotes for poisoning by alcohols that form toxic metabolites.

Science.gov (United States)

McMartin, Kenneth; Jacobsen, Dag; Hovda, Knut Erik

2016-03-01

The alcohols, methanol, ethylene glycol and diethylene glycol, have many features in common, the most important of which is the fact that the compounds themselves are relatively non-toxic but are metabolized, initially by alcohol dehydrogenase, to various toxic intermediates. These compounds are readily available worldwide in commercial products as well as in homemade alcoholic beverages, both of which lead to most of the poisoning cases, from either unintentional or intentional ingestion. Although relatively infrequent in overall occurrence, poisonings by metabolically-toxic alcohols do unfortunately occur in outbreaks and can result in severe morbidity and mortality. These poisonings have traditionally been treated with ethanol since it competes for the active site of alcohol dehydrogenase and decreases the formation of toxic metabolites. Although ethanol can be effective in these poisonings, there are substantial practical problems with its use and so fomepizole, a potent competitive inhibitor of alcohol dehydrogenase, was developed for a hopefully better treatment for metabolically-toxic alcohol poisonings. Fomepizole has few side effects and is easy to use in practice and it may obviate the need for haemodialysis in some, but not all, patients. Hence, fomepizole has largely replaced ethanol as the toxic alcohol antidote in many countries. Nevertheless, ethanol remains an important alternative because access to fomepizole can be limited, the cost may appear excessive, or the physician may prefer ethanol due to experience. © 2015 The British Pharmacological Society.

Ligand and Structure-Based Approaches for the Identification of Peptide Deformylase Inhibitors as Antibacterial Drugs.

Science.gov (United States)

Gao, Jian; Liang, Li; Zhu, Yasheng; Qiu, Shengzhi; Wang, Tao; Zhang, Ling

2016-07-15

Peptide deformylase (PDF) is a metalloprotease catalyzing the removal of a formyl group from newly synthesized proteins, which makes it an important antibacterial drug target. Given the importance of PDF inhibitors like actinonin in antibacterial drug discovery, several reported potent PDF inhibitors were used to develop pharmacophore models using the Galahad module of Sybyl 7.1 software. Generated pharmacophore models were composed of two donor atom centers, four acceptor atom centers and two hydrophobic groups. Model-1 was screened against the Zinc database and several compounds were retrieved as hits. Compounds with Qfit values of more than 60 were employed to perform a molecular docking study with the receptor Escherichia coli PDF, then compounds with docking score values of more than 6 were used to predict the in silico pharmacokinetic and toxicity risk via OSIRIS property explorer. Two known PDF inhibitors were also used to perform a molecular docking study with E. coli PDF as reference molecules. The results of the molecular docking study were validated by reproducing the crystal structure of actinonin. Molecular docking and in silico pharmacokinetic and toxicity prediction studies suggested that ZINC08740166 has a relatively high docking score of 7.44 and a drug score of 0.78.

Genome-Wide Identification and Functional Analysis of the Calcineurin B-like Protein and Calcineurin B-like Protein-Interacting Protein Kinase Gene Families in Turnip (Brassica rapa var. rapa

Directory of Open Access Journals (Sweden)

Xin Yin

2017-07-01

Full Text Available The calcineurin B-like protein (CBL–CBL-interacting protein kinase (CIPK complex has been identified as a primary component in calcium sensors that perceives various stress signals. Turnip (Brassica rapa var. rapa has been widely cultivated in the Qinghai–Tibet Plateau for a century as a food crop of worldwide economic significance. These CBL–CIPK complexes have been demonstrated to play crucial roles in plant response to various environmental stresses. However, no report is available on the genome-wide characterization of these two gene families in turnip. In the present study, 19 and 51 members of the BrrCBL and BrrCIPK genes, respectively, are first identified in turnip and phylogenetically grouped into three and two distinct clusters, respectively. The expansion of these two gene families is mainly attributable to segmental duplication. Moreover, the differences in expression patterns in quantitative real-time PCR, as well as interaction profiles in the yeast two-hybrid assay, suggest the functional divergence of paralog genes during long-term evolution in turnip. Overexpressing and complement lines in Arabidopsis reveal that BrrCBL9.2 improves, but BrrCBL9.1 does not affect, salt tolerance in Arabidopsis. Thus, the expansion of the BrrCBL and BrrCIPK gene families enables the functional differentiation and evolution of some new gene functions of paralog genes. These paralog genes then play prominent roles in turnip's adaptation to the adverse environment of the Qinghai–Tibet Plateau. Overall, the study results contribute to our understanding of the functions of the CBL–CIPK complex and provide basis for selecting appropriate genes for the in-depth functional studies of BrrCBL–BrrCIPK in turnip.

Molecular Modeling and docking of Wheat Hydroquinone Glucosyl transferase by using Hydroquinone, Phenyl phosphorodiamate and n-(n butyl) Phosphorothiocic Triamide as Inhibitors

Science.gov (United States)

Huma, Tayyaba; Maryam, Arooma; qamar, Tahir ul

2014-01-01

In agriculture high urease activity during urea fertilization causes substantial environmental and economical problems by releasing abnormally large amount of ammonia into the atmosphere which leads to plant damage as well as ammonia toxicity. All over the world, urea is the most widely applied nitrogen fertilizer. Due to the action of enzyme urease; urea nitrogen is lost as volatile ammonia. For efficient use of nitrogen fertilizer, urease inhibitor along with the urea fertilizer is one of the best promising strategies. Urease inhibitors also provide an insight in understanding the mechanism of enzyme catalyzed reaction, the role of various amino acids in catalytic activity present at the active site of enzyme and the importance of nickel to this metallo enzyme. By keeping it in view, the present study was designed to dock three urease inhibitors namely Hydroquinone (HQ), Phenyl Phosphorodiamate (PPD) and N-(n-butyl) Phosphorothiocic triamide (NBPT) against Hydroquinone glucosyltransferase using molecular docking approach. The 3D structure of Hydroquinone glucosyltransferase was predicted using homology modeling approach and quality of the structure was assured using Ramachandran plot. This study revealed important interactions among the urease inhibitors and Hydroquinone glucosyltransferase. Thus, it can be inferred that these inhibitors may serve as future anti toxic constituent against plant toxins. PMID:24748751

GSK-3β/NFAT Signaling Is Involved in Testosterone-Induced Cardiac Myocyte Hypertrophy.

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Javier Duran

Full Text Available Testosterone induces cardiac hypertrophy through a mechanism that involves a concerted crosstalk between cytosolic and nuclear signaling pathways. Nuclear factor of activated T-cells (NFAT is associated with the promotion of cardiac hypertrophy, glycogen synthase kinase-3β (GSK-3β is considered to function as a negative regulator, mainly by modulating NFAT activity. However, the role played by calcineurin-NFAT and GSK-3β signaling in testosterone-induced cardiac hypertrophy has remained unknown. Here, we determined that testosterone stimulates cardiac myocyte hypertrophy through NFAT activation and GSK-3β inhibition. Testosterone increased the activity of NFAT-luciferase (NFAT-Luc in a time- and dose-dependent manner, with the activity peaking after 24 h of stimulation with 100 nM testosterone. NFAT-Luc activity induced by testosterone was blocked by the calcineurin inhibitors FK506 and cyclosporine A and by 11R-VIVIT, a specific peptide inhibitor of NFAT. Conversely, testosterone inhibited GSK-3β activity as determined by increased GSK-3β phosphorylation at Ser9 and β-catenin protein accumulation, and also by reduction in β-catenin phosphorylation at residues Ser33, Ser37, and Thr41. GSK-3β inhibition with 1-azakenpaullone or a GSK-3β-targeting siRNA increased NFAT-Luc activity, whereas overexpression of a constitutively active GSK-3β mutant (GSK-3βS9A inhibited NFAT-Luc activation mediated by testosterone. Testosterone-induced cardiac myocyte hypertrophy was established by increased cardiac myocyte size and [3H]-leucine incorporation (as a measurement of cellular protein synthesis. Calcineurin-NFAT inhibition abolished and GSK-3β inhibition promoted the hypertrophy stimulated by testosterone. GSK-3β activation by GSK-3βS9A blocked the increase of hypertrophic markers induced by testosterone. Moreover, inhibition of intracellular androgen receptor prevented testosterone-induced NFAT-Luc activation. Collectively, these results

Dextromethorphan, chlorphenamine and serotonin toxicity: case report and systematic literature review

Science.gov (United States)

Monte, Andrew A; Chuang, Ryan; Bodmer, Michael

2010-01-01

The aim of this review was to describe a patient with serotonin toxicity after an overdose of dextromethorphan and chlorphenamine and to perform a systematic literature review exploring whether dextromethorphan and chlorphenamine may be equally contributory in the development of serotonin toxicity in overdose. A Medline literature review was undertaken to identify cases of serotonin toxicity due to dextromethorphan and/or chlorphenamine. Case reports were included if they included information on the ingested dose or plasma concentrations of dextromethorphan and/or chlorphenamine, information about co-ingestions and detailed clinical information to evaluate for serotonin toxicity. Cases were reviewed by two toxicologists and serotonin toxicity, defined by the Hunter criteria, was diagnosed when appropriate. The literature was then reviewed to evaluate whether chlorphenamine may be a serotonergic agent. One hundred and fifty-five articles of dextromethorphan or chlorphenamine poisoning were identified. There were 23 case reports of dextromethorphan, of which 18 were excluded for lack of serotonin toxicity. No cases were identified in which serotonin toxicity could be solely attributed to chlorphenamine. This left six cases of dextrometorphane and/or chlorphenamine overdose, including our own, in which serotonin toxicity could be diagnosed based on the presented clinical information. In three of the six eligible cases dextromethorphan and chlorphenamine were the only overdosed drugs. There is substantial evidence from the literature that chlorphenamine is a similarly potent serotonin re-uptake inhibitor when compared with dextrometorphan. Chlorphenamine is a serotonergic medication and combinations of chlorphenamine and dextromethorphan may be dangerous in overdose due to an increased risk of serotonin toxicity. PMID:21175434

Encapsulation-Induced Stress Helps Saccharomyces cerevisiae Resist Convertible Lignocellulose Derived Inhibitors

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Johan O. Westman

2012-09-01

Full Text Available The ability of macroencapsulated Saccharomyces cerevisiae CBS8066 to withstand readily and not readily in situ convertible lignocellulose-derived inhibitors was investigated in anaerobic batch cultivations. It was shown that encapsulation increased the tolerance against readily convertible furan aldehyde inhibitors and to dilute acid spruce hydrolysate, but not to organic acid inhibitors that cannot be metabolized anaerobically. Gene expression analysis showed that the protective effect arising from the encapsulation is evident also on the transcriptome level, as the expression of the stress-related genes YAP1, ATR1 and FLR1 was induced upon encapsulation. The transcript levels were increased due to encapsulation already in the medium without added inhibitors, indicating that the cells sensed low stress level arising from the encapsulation itself. We present a model, where the stress response is induced by nutrient limitation, that this helps the cells to cope with the increased stress added by a toxic medium, and that superficial cells in the capsules degrade convertible inhibitors, alleviating the inhibition for the cells deeper in the capsule.

Interdisciplinary management of EGFR-inhibitor-induced skin reactions: a German expert opinion.

Science.gov (United States)

Potthoff, K; Hofheinz, R; Hassel, J C; Volkenandt, M; Lordick, F; Hartmann, J T; Karthaus, M; Riess, H; Lipp, H P; Hauschild, A; Trarbach, T; Wollenberg, A

2011-03-01

Anti-epidermal growth factor receptor treatment strategies, i.e. monoclonal antibodies such as cetuximab and panitumumab, or epidermal growth factor receptor (EGFR) small molecule tyrosine kinase inhibitors, such as erlotinib and gefitinib, have expanded the treatment options for different tumor types. Dermatologic toxic effects are the most common side-effects of EGFR inhibitor therapy. They can profoundly affect the patient's quality of life. The aim of this study was to provide interdisciplinary expert recommendations on how to treat patients with skin reactions undergoing anti-EGFR treatment. An expert panel from Germany with expertise in medical oncology, dermatology or clinical pharmacology was convened to develop expert recommendations based on published peer-reviewed literature. The expert recommendations for the state-of-the-art treatment of skin reactions induced by EGFR inhibitor therapy include recommendations for diagnostics and grading as well as grade-specific and stage-adapted treatment approaches and preventive measures. It was concluded that EGFR-inhibitor-related dermatologic reactions should always be treated combining basic care of the skin and a specific therapy adapted to stage and grade of skin reaction. For grade 2 and above, specific treatment recommendations for early- and later-stage skin reactions induced by EGFR-inhibitor therapy were proposed. This paper presents a German national expert opinion for the treatment of skin reactions in patients receiving EGFR inhibitor therapy.

Untitled

African Journals Online (AJOL)

Elamin

Krüger B, Fischereder M, Jauch KW, Graeb C,. Hoffmann U, Böger CA, Banas B, Obed A. Schlitt HJ,. Krämer BK. Five-year follow-up after late conversion from calcineurin inhibitors to sirolimus in patients with chronic renal allograff dysfunction. Transplant Proc. 2007 Mar,39(2):518-21. 54. Schena FP, Pascoe MD, Albertu J, ...

First-in-human study of the toxicity, pharmacokinetics, and pharmacodynamics of CG200745, a pan-HDAC inhibitor, in patients with refractory solid malignancies.

Science.gov (United States)

Kim, Kyu-pyo; Park, Seong Joon; Kim, Jeong-Eun; Hong, Yong Sang; Lee, Jae-Lyun; Bae, Kyun-Seop; Cha, Hyunju; Kwon, Sool-Ki; Ro, Seonggu; Cho, JoongMyung; Kim, Tae Won

2015-10-01

The aim of the present study was to assess the safety, maximum tolerated dose (MTD), pharmacokinetics, pharmacodynamics, and efficacy of single and multiple doses of intravenous CG200745, a novel histone deacetylase (HDAC) inhibitor, in patients with advanced solid malignancies. Two to six patients received intravenous CG200745 according to the 2 + 4 dose-escalating method. This first-in-human trial was comprised of two parts: Part 1 was a single ascending dose, and Part 2 was multiple ascending doses weekly for 3 weeks, and then 1 week off. For the first cycle, pharmacokinetic sampling for CG200745 and pharmacodynamic sampling for acetylated histone H4 in peripheral blood mononuclear cells (PBMCs) were performed on day 1 for Part 1 and on days 1 and 15 for Part 2. Examination of acetylated histone H4 in pre- and post-biopsy samples was performed in accessible patients. In all, 28 patients were treated at 13 dose levels (1.8-250 mg/m(2)) and received a total of 71 cycles of CG200745. Hematologic toxicities included grade 3/4 neutropenia (22.2 %) that did not last a week and non-hematologic toxicities included fatigue (22.2 %) and anorexia (16.7 %) that did not exceed grade 2. No dose-limiting toxic effects were noted. Dose proportionality was observed for both the maximum concentration and area under the curve. The elimination half-life was 5.67 ± 2.69 h (mean ± standard deviation). An increase in PBMC acetylated histone H4 was observed at dose levels up to 51 mg/m(2), which plateaued at higher dose levels. At 24 h, 75 % of patients (6/8) showed higher relative acetylation in tumor tissue compared to PBMCs. Although there was no partial or complete response, 57.1 % of patients (16/28) had stable disease that lasted at least 6 weeks. CG200745 can be safely administered at effective dose levels that inhibit HDAC in PBMCs and tumor tissue. Although MTD was not reached, further escalation was not performed because acetylated histone H4 plateaued at dose

Difficult to control atopic dermatitis

Science.gov (United States)

2013-01-01

Difficult to control atopic dermatitis (AD) presents a therapeutic challenge and often requires combinations of topical and systemic treatment. Anti-inflammatory treatment of severe AD most commonly includes topical glucocorticosteroids and topical calcineurin antagonists used for exacerbation management and more recently for proactive therapy in selected cases. Topical corticosteroids remain the mainstay of therapy, the topical calcineurin inhibitors tacrolimus and pimecrolimus are preferred in certain locations. Systemic anti-inflammatory treatment is an option for severe refractory cases. Microbial colonization and superinfection contribute to disease exacerbation and thus justify additional antimicrobial / antiseptic treatment. Systemic antihistamines (H1) may relieve pruritus but do not have sufficient effect on eczema. Adjuvant therapy includes UV irradiation preferably of UVA1 wavelength. “Eczema school” educational programs have been proven to be helpful. PMID:23663504

Bidirectional Regulation of Amyloid Precursor Protein-Induced Memory Defects by Nebula/DSCR1: A Protein Upregulated in Alzheimer's Disease and Down Syndrome.

Science.gov (United States)

Shaw, Jillian L; Zhang, Shixing; Chang, Karen T

2015-08-12

Aging individuals with Down syndrome (DS) have an increased risk of developing Alzheimer's disease (AD), a neurodegenerative disorder characterized by impaired memory. Memory problems in both DS and AD individuals usually develop slowly and progressively get worse with age, but the cause of this age-dependent memory impairment is not well understood. This study examines the functional interactions between Down syndrome critical region 1 (DSCR1) and amyloid-precursor protein (APP), proteins upregulated in both DS and AD, in regulating memory. Using Drosophila as a model, we find that overexpression of nebula (fly homolog of DSCR1) initially protects against APP-induced memory defects by correcting calcineurin and cAMP signaling pathways but accelerates the rate of memory loss and exacerbates mitochondrial dysfunction in older animals. We report that transient upregulation of Nebula/DSCR1 or acute pharmacological inhibition of calcineurin in aged flies protected against APP-induced memory loss. Our data suggest that calcineurin dyshomeostasis underlies age-dependent memory impairments and further imply that chronic Nebula/DSCR1 upregulation may contribute to age-dependent memory impairments in AD in DS. Most Down syndrome (DS) individuals eventually develop Alzheimer's disease (AD)-like dementia, but mechanisms underlying this age-dependent memory impairment remain poorly understood. This study examines Nebula/Down syndrome critical region 1 (DSCR1) and amyloid-precursor protein (APP), proteins upregulated in both DS and AD, in regulating memory. We uncover a previously unidentified role for Nebula/DSCR1 in modulating APP-induced memory defects during aging. We show that upregulation of Nebula/DSCR1, an inhibitor of calcineurin, rescues APP-induced memory defects in young flies but enhances memory loss of older flies. Excitingly, transient Nebula/DSCR1 overexpression or calcineurin inhibition in aged flies ameliorates APP-mediated memory problems. These results

Changes in Pre- and Post-Exercise Gene Expression among Patients with Chronic Kidney Disease and Kidney Transplant Recipients.

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Dawn K Coletta

Full Text Available Decreased insulin sensitivity blunts the normal increase in gene expression from skeletal muscle after exercise. In addition, chronic inflammation decreases insulin sensitivity. Chronic kidney disease (CKD is an inflammatory state. How CKD and, subsequently, kidney transplantation affects skeletal muscle gene expression after exercise are unknown.Study cohort: non-diabetic male/female 4/1, age 52±2 years, with end-stage CKD who underwent successful kidney transplantation. The following were measured both pre-transplant and post-transplant and compared to normals: Inflammatory markers, euglycemic insulin clamp studies determine insulin sensitivity, and skeletal muscle biopsies performed before and within 30 minutes after an acute exercise protocol. Microarray analyses were performed on the skeletal muscle using the 4x44K Whole Human Genome Microarrays. Since nuclear factor of activated T cells (NFAT plays an important role in T cell activation and calcineurin inhibitors are mainstay immunosuppression, calcineurin/NFAT pathway gene expression was compared at rest and after exercise. Log transformation was performed to prevent skewing of data and regression analyses comparing measures pre- and post-transplant performed.Markers of inflammation significantly improved post-transplantation. Insulin infusion raised glucose disposal slightly lower post-transplant compared to pre-transplant, but not significantly, thus concluding differences in insulin sensitivity were similar. The overall pattern of gene expression in response to exercise was reduced both pre-and post-transplant compared to healthy volunteers. Although significant changes were observed among NFAT/Calcineurin gene at rest and after exercise in normal cohort, there were no significant differences comparing NFAT/calcineurin pathway gene expression pre- and post-transplant.Despite an improvement in serum inflammatory markers, no significant differences in glucose disposal were observed post

Evaluation of some non-toxic thiadiazole derivatives as bronze corrosion inhibitors in aqueous solution

International Nuclear Information System (INIS)

Varvara, Simona; Muresan, Liana Maria; Rahmouni, Kamal; Takenouti, Hisasi

2008-01-01

The inhibiting effect of four innoxious thiadiazole derivatives (2-mercapto-5-amino-1,3,4-thiadiazole (MAT), 2-mercapto-5-acetylamino-1,3,4-thiadiazole (MAcAT), 2-mercapto-5-methyl-1,3,4-thiadiazole (MMeT) and 2-mercapto-5-phenylamino-1,3,4-thiadiazole (MPhAT)) on bronze corrosion in an aerated solution of 0.2 g L -1 Na 2 SO 4 + 0.2 g L -1 NaHCO 3 at pH 5 was studied by potentiodynamic voltammetry and electrochemical impedance spectroscopy. The corrosion parameters determined from the polarisation curves indicate that the addition of the investigated thiadiazole derivatives decreases both cathodic and anodic current densities, due to an inhibition of the corrosion process, through the adsorption of thiadiazoles on the bronze surface. The inhibiting effect of the investigated organic compounds appears to be more pronounced on the anodic process than on the cathodic one and, except for the case MPhAT, it is enhanced by the increases of the inhibitors' concentration. The adsorption of the thiadiazole derivatives on bronze was confirmed by the presence of the nitrogen atoms in the EDX spectra of the bronze exposed to inhibitor-containing solutions. The magnitude of polarisation resistance values and, consequently, the inhibition efficiencies are influenced by the molecular structure of thiadiazole derivatives. The strongest inhibition was noticed in the presence of compounds with phenyl amino- or amino-functionalities in their molecules. The maximum protection efficiencies were obtained by addition of: 5 mM MAT (95.9%), 1 mM MAcAT (95.7%), 5 mM MMeT (92.6%) and 0.1 mM MPhAT (97%). EIS measurements also revealed that the inhibitor effectiveness of the optimal concentrations of thiadiazole is time-dependent

Evaluation of some non-toxic thiadiazole derivatives as bronze corrosion inhibitors in aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Varvara, Simona [Department of Topography, ' 1 Decembrie 1918' University, 11-13 Nicolae Iorga Street, 510009 Alba Iulia (Romania); Muresan, Liana Maria [Department of Physical Chemistry, ' Babes-Bolyai' University, 11 Arany-Janos Street, 400028 Cluj-Napoca (Romania)], E-mail: limur@chem.ubbcluj.ro; Rahmouni, Kamal; Takenouti, Hisasi [UPMC LISE - UPR 15 of the CNRS, ' Pierre and Marie Curie' University, Paris (France)

2008-09-15

The inhibiting effect of four innoxious thiadiazole derivatives (2-mercapto-5-amino-1,3,4-thiadiazole (MAT), 2-mercapto-5-acetylamino-1,3,4-thiadiazole (MAcAT), 2-mercapto-5-methyl-1,3,4-thiadiazole (MMeT) and 2-mercapto-5-phenylamino-1,3,4-thiadiazole (MPhAT)) on bronze corrosion in an aerated solution of 0.2 g L{sup -1} Na{sub 2}SO{sub 4} + 0.2 g L{sup -1} NaHCO{sub 3} at pH 5 was studied by potentiodynamic voltammetry and electrochemical impedance spectroscopy. The corrosion parameters determined from the polarisation curves indicate that the addition of the investigated thiadiazole derivatives decreases both cathodic and anodic current densities, due to an inhibition of the corrosion process, through the adsorption of thiadiazoles on the bronze surface. The inhibiting effect of the investigated organic compounds appears to be more pronounced on the anodic process than on the cathodic one and, except for the case MPhAT, it is enhanced by the increases of the inhibitors' concentration. The adsorption of the thiadiazole derivatives on bronze was confirmed by the presence of the nitrogen atoms in the EDX spectra of the bronze exposed to inhibitor-containing solutions. The magnitude of polarisation resistance values and, consequently, the inhibition efficiencies are influenced by the molecular structure of thiadiazole derivatives. The strongest inhibition was noticed in the presence of compounds with phenyl amino- or amino-functionalities in their molecules. The maximum protection efficiencies were obtained by addition of: 5 mM MAT (95.9%), 1 mM MAcAT (95.7%), 5 mM MMeT (92.6%) and 0.1 mM MPhAT (97%). EIS measurements also revealed that the inhibitor effectiveness of the optimal concentrations of thiadiazole is time-dependent.

Cholinesterase inhibitors and hospitalization for bradycardia: a population-based study.

Directory of Open Access Journals (Sweden)

Laura Y Park-Wyllie

2009-09-01

inhibitor therapy was associated with a more than doubling of the risk of hospitalization for bradycardia. Resumption of therapy following discharge was common, suggesting that the cardiovascular toxicity of cholinesterase inhibitors is underappreciated by clinicians.

Differential Antitumoral Properties and Renal-Associated Tissue Damage Induced by Tacrolimus and Mammalian Target of Rapamycin Inhibitors in Hepatocarcinoma: In Vitro and In Vivo Studies.

Directory of Open Access Journals (Sweden)

Elena Navarro-Villarán

Full Text Available Orthotopic liver transplantation (OLT is the recommended treatment for patients at early stages of hepatocarcinoma (HCC with potential portal hypertension and/or bilirubinemia, but without vascular-associated diseases. The patients are receiving immunosuppressive therapy to reduce graft rejection, but differential side effects have been related to calcineurin and mTOR inhibitor administration regarding tumor recurrence and nephrotoxicity. The in vitro studies showed that Tacrolimus exerted a more potent pro-apoptotic effect than Everolimus (Huh 7>Hep 3B>HepG2, being sirolimus only active in Hep3B cell line. Tacrolimus and Everolimus exerted potent antiproliferative properties in Huh 7 and Hep3B in which cells Sirolimus was inactive. Interestingly, Tacrolimus- and Everolimus-dependent G0/G1 cell accumulation occurred as a consequence of drastic reduction in S, as well as in S and G2+M phases, respectively. The in vivo studies support data on the more effective antitumoral properties of Everolimus, eventual risk of pro-angiogenic tumoral properties and nephrotoxicity of Tacrolimus, and pro-proliferative properties of Sirolimus in tumors developed in nude mice.

Assay techniques for detection of exposure to sulfur mustard, cholinesterase inhibitors, sarin, soman, GF, and cyanide. Technical bulletin

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-05-01

This technical bulletin provides analytical techniques to identify toxic chemical agents in urine or blood samples. It is intended to provide the clinician with laboratory tests to detect exposure to sulfur mustard, cholinesterase inhibitors, sarin, soman, GF, and cyanide.

Marine toxicity and persistence of surfactants used in the petroleum producing industry

International Nuclear Information System (INIS)

Maddin, C.M.

1991-01-01

This paper presents a survey of marine toxicity and biodegradability data for surfactants used in the petroleum industry. Surfactants are key chemicals in the formulation of products such as emulsifiers, demulsifiers, dispersants and inhibitors. They are also used directly as foaming and defoaming agents. Because they function at low concentrations, below 1%, and have a tendency to adsorb on solid surfaces, their long-term environmental effects are minimal. In applications such as cementing, surfactants cannot migrate into the environment and, thus, have no bioavailability. The possibility of environmental contamination has caused well operators and regulatory agencies to require fish toxicity and persistence data for products used in servicing wells. This data has been organized for nonionic, anionic, cationic and amphoteric surfactants. Nonionic surfactants are toxic to fish at concentrations below 10 mg/L to over 2500 mg/L depending on their chemical compositions. Anionic surfactants are toxic to fish at concentrations under 1 mg/L to several hundred mg/L depending on their chemical compositions. cationic and amphoteric surfactants are generally toxic to fish at concentrations below 50 mg/L. Overall efforts are aimed at low toxicity and high biodegradability with the least compromise in product efficiency. This requires the continual testing and environmental evaluation of surfactants summarized herein

Small-molecule quinolinol inhibitor identified provides protection against BoNT/A in mice.

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Padma Singh

Full Text Available Botulinum neurotoxins (BoNTs, etiological agents of the life threatening neuroparalytic disease botulism, are the most toxic substances currently known. The potential for the use as bioweapon makes the development of small-molecule inhibitor against these deadly toxins is a top priority. Currently, there are no approved pharmacological treatments for BoNT intoxication. Although an effective vaccine/immunotherapy is available for immuno-prophylaxis but this cannot reverse the effects of toxin inside neurons. A small-molecule pharmacological intervention, especially one that would be effective against the light chain protease, would be highly desirable. Similarity search was carried out from ChemBridge and NSC libraries to the hit (7-(phenyl(8-quinolinylaminomethyl-8-quinolinol; NSC 84096 to mine its analogs. Several hits obtained were screened for in silico inhibition using AutoDock 4.1 and 19 new molecules selected based on binding energy and Ki. Among these, eleven quinolinol derivatives potently inhibited in vitro endopeptidase activity of botulinum neurotoxin type A light chain (rBoNT/A-LC on synaptosomes isolated from rat brain which simulate the in vivo system. Five of these inhibitor molecules exhibited IC(50 values ranging from 3.0 nM to 10.0 µM. NSC 84087 is the most potent inhibitor reported so far, found to be a promising lead for therapeutic development, as it exhibits no toxicity, and is able to protect animals from pre and post challenge of botulinum neurotoxin type A (BoNT/A.

Corrosion protection with eco-friendly inhibitors

Science.gov (United States)

Shahid, Muhammad

2011-12-01

Corrosion occurs as a result of the interaction of a metal with its environment. The extent of corrosion depends on the type of metal, the existing conditions in the environment and the type of aggressive ions present in the medium. For example, CO3-2 and NO-3 produce an insoluble deposit on the surface of iron, resulting in the isolation of metal and consequent decrease of corrosion. On the other hand, halide ions are adsorbed selectively on the metal surface and prevent formation of the oxide phase on the metal surface, resulting in continuous corrosion. Iron, aluminum and their alloys are widely used, both domestically and industrially. Linear alkylbenzene and linear alkylbenzene sulfonate are commonly used as detergents. They have also been found together in waste water. It is claimed that these chemicals act as inhibitors for stainless steel and aluminum. Release of toxic gases as a result of corrosion in pipelines may lead in certain cases to air pollution and possible health hazards. Therefore, there are two ways to look at the relationship between corrosion and pollution: (i) corrosion of metals and alloys due to environmental pollution and (ii) environmental pollution as a result of corrosion protection. This paper encompasses the two scenarios and possible remedies for various cases, using 'green' inhibitors obtained either from plant extracts or from pharmaceutical compounds. In the present study, the effect of piperacillin sodium as a corrosion inhibitor for mild steel was investigated using a weight-loss method as well as a three-electrode dc electrochemical technique. It was found that the corrosion rate decreased as the concentration of the inhibitor increased up to 9×10-4 M 93% efficiency was exhibited at this concentration.

César Augusto Restrepo Valencia, Consuelo Vélez Álvarez Abstract Objective. To evaluate the effectiveness of calcineurin ciclosporin and tacrolimus inhibitors to induce remission in patients with refractory lupus nephritis. Patients, materials and methods. Patients with lupus nephritis class IV-G who despite receiving therapy with high doses of steroid and with a cytostatic (cyclophosphamide or mycophenolate for 3 months had not been able to induce some kind of remission.The exclusion criteria were creatinine levels greater than 3 mg / dl, pregnancy, previous history of exposure to calcineurin inhibitors, cancer, active infections, uncontrolled hypertension, and negligence with medication intake. The recommended dose of cyclosporine was 3 mg / kg / day and tacrolimus 0.1 mg / kg / day, in joint with prednisone 0.3 mg / kg / day, cyclophosphamide 1 mg / kg / day or mycophenolate mofetil 1 gram every 12 hours. The cyclophosphamide was administered only during 6 months, after which it was changed to azathioprine at doses of 1 mg / kg / day. Still, mycophenolate was continued at the same dose. All patients completed a minimum period of 12 months follow-up, it was considered that patients achieved partial remission when proteinuria decreased by 50% of the baseline value or its value decreased to less than 1 gram in 24 hours, decrease of leukocytes count and red blood cells in urine of 50%, and creatinine values were stable. A complete remission was considered when there was a reduction in proteinuria in a value less than 300 mg per 24 hours, urinary sediment with less than 3 red blood cells, less than 5 leukocyte for each high power microscopic field, and a creatinine value reduction by 50% or reaching a normal value. Results. Twelve patients met the inclusion criteria and initiated the calcineurin inhibitor protocol. Two presented accelerated deterioration in their function and required chronic dialysis therapy. Ten patients with active treatment completed 12 months

Directory of Open Access Journals (Sweden)

César Augusto Restrepo Valencia

2014-10-01

Full Text Available Objective: To evaluate the effectiveness of calcineurin ciclosporin and tacrolimus inhibitors to induce remission in patients with refractory lupus nephritis. Patients, materials and methods: Patients with lupus nephritis class IV-G who despite receiving the rapy with high doses of steroid and with a cytostatic (cyclophosphamide or mycophenolate for 3 months had not been able to induce some kind of remission.The exclusion criteria were creatinine levels greater than 3 mg / dl, pregnancy, previous history of exposure to calcineurin inhibitors, cancer, active infections, uncontrolled hypertension, and negligence with medication intake. The recommended dose of cyclosporine was 3 mg / kg / day and tacrolimus 0.1 mg / kg / day, in joint with prednisone 0.3 mg / kg / day, cyclophosphamide 1 mg / kg / day or mycophenolate mofetil 1 gram every 12 hours. The cyclophosphamide was administered only during 6 months, after which it was changed to azathioprine at doses of 1 mg / kg / day. Still, mycophenolate was continued at the same dose. All patients completed a minimum period of 12 months follow-up, it was considered that patients achieved partial remission when proteinuria decreased by 50% of the baseline value or its value decreased to less than 1 gram in 24 hours, decrease of leukocytes count and red blood cells in urine of 50%, and creatinine values were stable. A complete remission was considered when there was a reduction in proteinuria in a value less than 300 mg per 24 hours, urinary sediment with less than 3 red blood cells, less than 5 leukocyte for each high power microscopic field, and a creatinine value reduction by 50% or reaching a normal value. Results: Twelve patients met the inclusion criteria and initiated the calcineurin inhibitor protocol. Two presented accelerated deterioration in their function and required chronic dialysis therapy. Ten patients with active treatment completed 12 months of followup, of which 4 (40% had partial

New and emerging trends in the treatment of atopic dermatitis

Directory of Open Access Journals (Sweden)

Christina M Gelbard

2009-01-01

Full Text Available Christina M Gelbard1, Adelaide A Hebert1,21Departments of Dermatology; 2Pediatrics, University of Texas-Houston, Houston, TX, USAAbstract: Atopic dermatitis is a chronic, inflammatory skin condition that affects 10% to 20% of children and 1% to 3% of adults in the US. Symptoms often result in sleeplessness, psychological stress, poor self-esteem, anxiety, and poor school or work performance. The cost of atopic dermatitis is estimated to be US$0.9 to 3.8 billion every year. Topical steroids are first-line treatment for atopic dermatitis, and recent advances in vehicle technologies have resulted in improved patient tolerability and compliance. Topical calcineurin inhibitors are also safe and effective topical treatments for atopic dermatitis, and provide an additional therapeutic option for patients with this disease. Systemic immunomodulators are used in the treatment of severe refractory disease. Cyclosporine, methotrexate, azathioprine, mycophenolate mofetil, and interferon gamma have been used in the management of severe atopic dermatitis. This review highlights the current and emerging trends in the treatment of atopic dermatitis.Keywords: atopic dermatitis, topical corticosteroids, calcineurin inhibitors, methotrexate, cyclosporine, mycophenolate mofetil, IFN-γ

Potential Use of Chemoprotectants against the Toxic Effects of Cyanotoxins: A Review.

Science.gov (United States)

Guzmán-Guillén, Remedios; Puerto, María; Gutiérrez-Praena, Daniel; Prieto, Ana I; Pichardo, Silvia; Jos, Ángeles; Campos, Alexandre; Vasconcelos, Vitor; Cameán, Ana M

2017-05-23

Cyanobacterial toxins, particularly microcystins (MCs) and cylindrospermopsin (CYN), are responsible for toxic effects in humans and wildlife. In order to counteract or prevent their toxicity, various strategies have been followed, such as the potential application of chemoprotectants. A review of the main substances evaluated for this aim, as well as the doses and their influence on cyanotoxin-induced toxicity, has been performed. A search of the literature shows that research on MCs is much more abundant than research on CYN. Among chemoprotectants, antioxidant compounds are the most extensively studied, probably because it is well known that oxidative stress is one of the toxic mechanisms common to both toxins. In this group, vitamin E seems to have the strongest protectant effect for both cyanotoxins. Transport inhibitors have also been studied in the case of MCs, as CYN cellular uptake is not yet fully elucidated. Further research is needed because systematic studies are lacking. Moreover, more realistic exposure scenarios, including cyanotoxin mixtures and the concomitant use of chemoprotectants, should be considered.

Pathophysiology of visual disorders induced by phosphodiesterase inhibitors in the treatment of erectile dysfunction

Directory of Open Access Journals (Sweden)

Moschos MM

2016-10-01

Full Text Available Marilita M Moschos, Eirini Nitoda 1st Department of Ophthalmology, Medical School, National & Kapodistrian University of Athens, Athens, Greece Aim: The aim of this review was to summarize the ocular action of the most common phosphodiesterase (PDE inhibitors used for the treatment of erectile dysfunction and the subsequent visual disorders.Method: This is a literature review of several important articles focusing on the pathophysiology of visual disorders induced by PDE inhibitors.Results: PDE inhibitors have been associated with ocular side effects, including changes in color vision and light perception, blurred vision, transient alterations in electroretinogram (ERG, conjunctival hyperemia, ocular pain, and photophobia. Sildenafil and tadalafil may induce reversible increase in intraocular pressure and be involved in the development of nonarteritic ischemic optic neuropathy. Reversible idiopathic serous macular detachment, central serous chorioretinopathy, and ERG disturbances have been related to the significant impact of sildenafil and tadalafil on retinal perfusion.Discussion: So far, PDE inhibitors do not seem to cause permanent toxic effects on chorioretinal tissue and photoreceptors. However, physicians should write down any visual symptom observed during PDE treatment and refer the patients to ophthalmologists. Keywords: erectile dysfunction, pathophysiological mechanisms, phosphodiesterase inhibitors, PDE5, visual disorders

Induction of the nuclear factor HIF-1α in acetaminophen toxicity: Evidence for oxidative stress

International Nuclear Information System (INIS)

James, Laura P.; Donahower, Brian; Burke, Angela S.; McCullough, Sandra; Hinson, Jack A.

2006-01-01

Hypoxia inducible factor (HIF) controls the transcription of genes involved in angiogenesis, erythropoiesis, glycolysis, and cell survival. HIF-1α levels are a critical determinant of HIF activity. The induction of HIF-1α was examined in the livers of mice treated with a toxic dose of APAP (300 mg/kg IP) and sacrificed at 1, 2, 4, 8, and 12 h. HIF-1α was induced at 1-12 h and induction occurred prior to the onset of toxicity. Pre-treatment of mice with N-acetylcysteine (1200 mg/kg IP) prevented toxicity and HIF-1α induction. In further studies, hepatocyte suspensions were incubated with APAP (1 mM) in the presence of an oxygen atmosphere. HIF-1α was induced at 1 h, prior to the onset of toxicity. Inclusion of cyclosporine A (10 μM), an inhibitor of mitochondrial permeability transition, oxidative stress, and toxicity, prevented the induction of HIF-1α. Thus, HIF-1α is induced before APAP toxicity and can occur under non-hypoxic conditions. The data suggest a role for oxidative stress in the induction of HIF-1α in APAP toxicity

Novel approaches to mitigating parathion toxicity: targeting cytochrome P450-mediated metabolism with menadione.

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Jan, Yi-Hua; Richardson, Jason R; Baker, Angela A; Mishin, Vladimir; Heck, Diane E; Laskin, Debra L; Laskin, Jeffrey D

2016-08-01

Accidental or intentional exposures to parathion, an organophosphorus (OP) pesticide, can cause severe poisoning in humans. Parathion toxicity is dependent on its metabolism by the cytochrome P450 (CYP) system to paraoxon (diethyl 4-nitrophenyl phosphate), a highly poisonous nerve agent and potent inhibitor of acetylcholinesterase. We have been investigating inhibitors of CYP-mediated bioactivation of OPs as a method of preventing or reversing progressive parathion toxicity. It is well recognized that NADPH-cytochrome P450 reductase, an enzyme required for the transfer of electrons to CYPs, mediates chemical redox cycling. In this process, the enzyme diverts electrons from CYPs to support chemical redox cycling, which results in inhibition of CYP-mediated biotransformation. Using menadione as the redox-cycling chemical, we discovered that this enzymatic reaction blocks metabolic activation of parathion in rat and human liver microsomes and in recombinant CYPs important to parathion metabolism, including CYP1A2, CYP2B6, and CYP3A4. Administration of menadione to rats reduces metabolism of parathion, as well as parathion-induced inhibition of brain cholinesterase activity. This resulted in inhibition of parathion neurotoxicity. Menadione has relatively low toxicity and is approved by the Food and Drug Administration for other indications. Its ability to block parathion metabolism makes it an attractive therapeutic candidate to mitigate parathion-induced neurotoxicity. © 2016 New York Academy of Sciences.

Calcineurin B in CD4+ T Cells Prevents Autoimmune Colitis by Negatively Regulating the JAK/STAT Pathway.

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Mencarelli, Andrea; Vacca, Maurizio; Khameneh, Hanif Javanmard; Acerbi, Enzo; Tay, Alicia; Zolezzi, Francesca; Poidinger, Michael; Mortellaro, Alessandra

2018-01-01

Calcineurin (Cn) is a protein phosphatase that regulates the activation of the nuclear factor of activated T-cells (NFAT) family of transcription factors, which are key regulators of T-cell development and function. Here, we generated a conditional Cnb1 mouse model in which Cnb1 was specifically deleted in CD4 + T cells (Cnb1 CD4 mice) to delineate the role of the Cn-NFAT pathway in immune homeostasis of the intestine. The Cnb1 CD4 mice developed severe, spontaneous colitis characterized at the molecular level by an increased T helper-1-cell response but an unaltered regulatory T-cell compartment. Antibiotic treatment ameliorated the intestinal inflammation observed in Cnb1 CD4 mice, suggesting that the microbiota contributes to the onset of colitis. CD4 + T cells isolated from Cnb1 CD4 mice produced high levels of IFNγ due to increased activation of the JAK2/STAT4 pathway induced by IL-12. Our data highlight that Cn signaling in CD4 + T cells is critical for intestinal immune homeostasis in part by inhibiting IL-12 responsiveness of CD4 + T cells.

The evolving field of kinase inhibitors in thyroid cancer.

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Marotta, V; Sciammarella, C; Vitale, M; Colao, A; Faggiano, A

2015-01-01

Most of the genetic events implicated in the pathogenesis of thyroid cancer (TC) involve genes with kinase activity. Thus, kinase inhibitors (KIs) are very relevant in this field. KIs are considered the most suitable treatment for patients with iodine-refractory differentiated TC; these patients comprise the subgroup with the poorer prognosis. To date, only sorafenib has been approved for this indication, but promising results have been reported with several other KIs. In particular, lenvatinib has demonstrated excellent efficacy, with both progression-free survival and objective tumour response being better than with sorafenib. Despite being considered to be well tolerated, both sorafenib and lenvatinib have shown a remarkable toxicity, which has led to dose reductions in the majority of patients and to treatment discontinuation in a significant proportion of cases. The role of KIs in differentiated TC may be revolutionised by the finding that selumetinib may restore a clinical response to radioactive iodine (RAI). Vandetanib and cabozantinib have been approved for the treatment of advanced, progressive medullary TC (MTC). Nevertheless, the toxicity of both compounds suggests their selective use in those patients with strong disease progression. Treatment with the mTOR-inhibitor everolimus, alone or in combination with somatostatin analogues, should be studied in metastatic MTC patients with slow progression of disease, these representing the vast majority of patients. KIs did not significantly impact on the clinical features of anaplastic TC (ATC). Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

First report on the structural exploration and prediction of new BPTES analogs as glutaminase inhibitors

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Amin, Sk. Abdul; Adhikari, Nilanjan; Gayen, Shovanlal; Jha, Tarun

2017-09-01

Glutaminase is one of the important key enzymes regulating cellular metabolism, growth, and proliferation in cancer. Therefore, it is being explored as a crucial target regarding anticancer drug design and development. However, none of the potent and selective glutaminase inhibitors is available in the market though two prototype glutaminase inhibitors are reported namely DON as well as BPTES. Due to severe toxicity in clinical trials, the use of DON is restricted. However, BPTES is an allosteric glutaminase inhibitor with less toxic profile and, therefore, lead optimization of BPTES may be a good option to develop newer drug candidates. In this study, a multi-QSAR modeling is carried out on a series of BPTES analogs. A significant connection between different descriptors and the glutaminase inhibitory activities is noticed by employing multiple linear regression, artificial neural network and support vector machine techniques. The classification-based QSAR such as linear discriminant analysis and Bayesian classification modeling are also performed to search important molecular fingerprints or substructures that may help in classifying the probability of finding 'active' and 'inactive' BPTES analogs. Moreover, HQSAR and Topomer CoMFA analyses are also performed. In addition, the SAR observations are interpreted with all these validated computational models along with the structure-based contours. Finally, new twenty two compounds are designed and predicted for their probable glutaminase inhibitory activity.

Phenytoin toxicity secondary to an oxcarbazepine-phenytoin 2C19 interaction.

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Soskin, David P; Kane, Ari J; Stern, Theodore A

2010-01-01

Polytherapy is common in the management of bipolar disorder, as are the side effects associated with this treatment strategy. The authors review the literature on drug-drug interactions involving oxcarbazepine and identify specific mechanisms that may have clinical importance. The authors provide a case report of a patient who developed phenytoin toxicity associated with an oxcarbazepine-phenytoin interaction. Co-administration of phenytoin and oxcarbazepine resulted in toxic levels of phenytoin. Therefore, the patient's daily dosage of oxcarbazepine and phenytoin were reduced. Although oxcarbazepine is an inducer of the 3A4 isoenzyme, it acts as an inhibitor of the 2C19 isoenzyme, and it can raise levels of other agents, for example, phenytoin, that are also metabolized by this isoenzyme.

Nephro and neurotoxicity of calcineurin inhibitors and mechanisms of rejections: A review on tacrolimus and cyclosporin in organ transplantation.

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Tolou-Ghamari, Zahra

2012-04-01

In the meadow of medical sciences substituting a diseased organ with a healthy one from another individual, dead or alive, to allow a human to stay alive could be consider as the most string event. In this article we review the history of transplantation, mechanisms of rejection, nephro-neurotoxicity of tacrolimus and cyclosporin in organ transplantations. Directory of Open Access Journals (DOAJ), Google Scholar, Pubmed (NLM), LISTA (EBSCO) and Web of Science have been searched. The first reference to the concept of organ transplantation and replacement for therapeutic purposes appears to be to Hua-To (136 to 208 A.D), who replaced diseased organs with healthy ones in patients under analgesia induced with a mixture of Indian hemp. In 1936, the first human renal transplant performed by Voronoy in Russia. The first liver transplant in humans was performed on March 1, 1963 by Starzl in Denver, USA. Medawar was the first to assert that rejection was an immunological response, with the inflammatory reaction due to lymphocyte infiltration. Consequently, rational immunosuppressive therapies could inhibit deleterious T-cell responses in an antigen specific manner. Searching related to the history of organ transplantation from mythic to modern times suggests that, to prevent graft rejection, minimize nephro and neuro toxicity monitoring of immunosupressive concentrations could provide an invaluable and essential aid in adjusting dosage to ensure adequate immunosuppression.

Treatment and Prevention of Breast Cancer Using Multifunctional Inhibitors of Cholesterol Biosynthesis

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2015-08-01

suggesting an allosteric modification of estrogen receptor  RO blocks the production of an estrogen regulated gene ( progesterone receptor) in...alternative targets in the pathway leading to the production of cholesterol, which might be regulated with less toxic inhibitors to control the progression of...to effectively treat and prevent cancers of the breast. Our goal was to identify alternative targets in the pathway leading to the production of

Tetomilast: new promise for phosphodiesterase-4 inhibitors?

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Bickston, Stephen J; Snider, Kenneth R; Kappus, Matthew R

2012-12-01

Tetomilast is a novel thiazole phosphodiesterase-4 (PDE-4) inhibitor, which may prove useful in both the treatment of inflammatory bowel disease (IBD) and chronic obstructive pulmonary disease (COPD). Here, the authors review the pharmacology of the drug, and offer critical review of the available data for use of tetomilast in the treatment of IBD. Peer-reviewed publications, including Phase I and II clinical trials, all other formats included. Tetomilast may be beneficial in IBD. Small differences in molecules and in recombinant proteins can translate into substantial differences in clinical effects and toxicity in IBD. This is a reasonable approach when exploring new options like tetomilast.

Comparing guidelines for the treatment of inflammatory bowel disease.

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Hanauer, Stephen B; Kirsner, Joseph B

2013-01-01

As we enter into the era of 'personalized medicine', many of the recommendations of 'evidence-based medicine' require scrutiny and adaptation to optimize individual outcomes. Several examples of these discrepancies are exemplified by the topics of aminosalicylate use in Crohn's disease, early use of biologic agents that target TNF and the role of calcineurin inhibitors versus anti-TNF agents in steroid-refractory ulcerative colitis.

Discovery and study of novel protein tyrosine phosphatase 1B inhibitors

Science.gov (United States)

Zhang, Qian; Chen, Xi; Feng, Changgen

2017-10-01

Protein tyrosine phosphatase 1B (PTP1B) is considered to be a target for therapy of type II diabetes and obesity. So it is of great significance to take advantage of a computer aided drug design protocol involving the structured-based virtual screening with docking simulations for fast searching small molecule PTP1B inhibitors. Based on optimized complex structure of PTP1B bound with specific inhibitor of IX1, structured-based virtual screening against a library of natural products containing 35308 molecules, which was constructed based on Traditional Chinese Medicine database@ Taiwan (TCM database@ Taiwan), was conducted to determine the occurrence of PTP1B inhibitors using the Lubbock module and CDOCKER module from Discovery Studio 3.1 software package. The results were further filtered by predictive ADME simulation and predictive toxic simulation. As a result, 2 good drug-like molecules, namely para-benzoquinone compound 1 and Clavepictine analogue 2 were identified ultimately with the dock score of original inhibitor (IX1) and the receptor as a threshold. Binding model analyses revealed that these two candidate compounds have good interactions with PTP1B. The PTP1B inhibitory activity of compound 2 hasn't been reported before. The optimized compound 2 has higher scores and deserves further study.

Metabolic complications associated with HIV protease inhibitor therapy.

Science.gov (United States)

Nolan, David

2003-01-01

HIV protease inhibitors were introduced into clinical practice over 7 years ago as an important component of combination antiretroviral drug regimens which in many ways revolutionised the treatment of HIV infection. The significant improvements in prognosis that have resulted from the use of these regimens, combined with the need for lifelong treatment, have increasingly focused attention on the adverse effects of antiretroviral drugs and on the metabolic complications of HIV protease inhibitors in particular. In this review, the cluster of metabolic abnormalities characterised by triglyceride-rich dyslipidaemia and insulin resistance associated with HIV protease inhibitor therapy are considered, along with implications for cardiovascular risk in patients affected by these complications. Toxicity profiles of individual drugs within the HIV protease inhibitor class are examined, as there is an increased recognition of significant intra-class differences both in terms of absolute risk of metabolic complications as well as the particular metabolic phenotype associated with these drugs. Guidelines for clinical assessment and treatment are emphasised, along with pathophysiological mechanisms that may provide a rational basis for the treatment of metabolic complications. Finally, these drug-specific effects are considered within the context of HIV-specific effects on lipid metabolism as well as lifestyle factors that have contributed to a rapidly increasing incidence of similar metabolic syndromes in the general population. These data highlight the importance of individualising patient management in terms of choice of antiretroviral regimen, assessment of metabolic outcomes and use of therapeutic interventions, based on the assessment of baseline (pre-treatment) metabolic status as well as the presence of potentially modifiable cardiovascular risk factors.

The phosphatase inhibitor menadione (vitamin K3) protects cells from EGFR inhibition by erlotinib and cetuximab.

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Perez-Soler, Roman; Zou, Yiyu; Li, Tianhong; Ling, Yi He

2011-11-01

Skin toxicity is the main side effect of epidermal growth factor receptor (EGFR) inhibitors, often leading to dose reduction or discontinuation. We hypothesized that phosphatase inhibition in the skin keratinocytes may prevent receptor dephosphorylation caused by EGFR inhibitors and be used as a new potential strategy for the prevention or treatment of this side effect. Menadione (Vitamin K3) was used as the prototype compound to test our hypothesis. HaCat human skin keratinocyte cells and A431 human squamous carcinoma cells were used. EGFR inhibition was measured by Western blotting and immunofluorescence. Phosphatase inhibition and reactive oxygen species (ROS) generation were measured by standard ELISA and fluorescence assays. Menadione caused significant and reversible EGFR activation in a dose-dependent manner starting at nontoxic concentrations. EGFR activation by menadione was associated with reversible protein tyrosine phosphatase inhibition, which seemed to be mediated by ROS generation as exposure to antioxidants prevented both menadione-induced ROS generation and phosphatase inhibition. Short-term coincubation of cells with nontoxic concentrations of menadione and the EGFR inhibitors erlotinib or cetuximab prevented EGFR dephosphorylation. Seventy-two-hour coincubation of cells with the highest nontoxic concentration of menadione and erlotinib provided for a fourfold cell growth inhibitory protection in HaCat human keratinocyte cells. Menadione at nontoxic concentrations causes EGFR activation and prevents EGFR dephosphorylation by erlotinib and cetuximab. This effect seems to be mediated by ROS generation and secondary phosphatase inhibition. Mild oxidative stress in skin keratinocytes by topical menadione may protect the skin from the toxicity secondary to EGFR inhibitors without causing cytotoxicity. ©2011 AACR

Inhibiting and Remodeling Toxic Amyloid-Beta Oligomer Formation Using a Computationally Designed Drug Molecule That Targets Alzheimer's Disease

Science.gov (United States)

Downey, Matthew A.; Giammona, Maxwell J.; Lang, Christian A.; Buratto, Steven K.; Singh, Ambuj; Bowers, Michael T.

2018-04-01

Alzheimer's disease (AD) is rapidly reaching epidemic status among a burgeoning aging population. Much evidence suggests the toxicity of this amyloid disease is most influenced by the formation of soluble oligomeric forms of amyloid β-protein, particularly the 42-residue alloform (Aβ42). Developing potential therapeutics in a directed, streamlined approach to treating this disease is necessary. Here we utilize the joint pharmacophore space (JPS) model to design a new molecule [AC0107] incorporating structural characteristics of known Aβ inhibitors, blood-brain barrier permeability, and limited toxicity. To test the molecule's efficacy experimentally, we employed ion mobility mass spectrometry (IM-MS) to discover [AC0107] inhibits the formation of the toxic Aβ42 dodecamer at both high (1:10) and equimolar concentrations of inhibitor. Atomic force microscopy (AFM) experiments reveal that [AC0107] prevents further aggregation of Aβ42, destabilizes preformed fibrils, and reverses Aβ42 aggregation. This trend continues for long-term interaction times of 2 days until only small aggregates remain with virtually no fibrils or higher order oligomers surviving. Pairing JPS with IM-MS and AFM presents a powerful and effective first step for AD drug development.

Serotonin and noradrenaline reuptake inhibitors improve micturition control in mice.

Directory of Open Access Journals (Sweden)

Marco Redaelli

Full Text Available Poor micturition control may cause profound distress, because proper voiding is mandatory for an active social life. Micturition results from the subtle interplay of central and peripheral components. It involves the coordination of autonomic and neuromuscular activity at the brainstem level, under the executive control of the prefrontal cortex. We tested the hypothesis that administration of molecules acting as reuptake inhibitors of serotonin, noradrenaline or both may exert a strong effect on the control of urine release, in a mouse model of overactive bladder. Mice were injected with cyclophosphamide (40 mg/kg, to increase micturition acts. Mice were then given one of four molecules: the serotonin reuptake inhibitor imipramine, its metabolite desipramine that acts on noradrenaline reuptake, the serotonin and noradrenaline reuptake inhibitor duloxetine or its active metabolite 4-hydroxy-duloxetine. Cyclophosphamide increased urine release without inducing overt toxicity or inflammation, except for increase in urothelium thickness. All the antidepressants were able to decrease the cyclophosphamide effects, as apparent from longer latency to the first micturition act, decreased number of urine spots and volume of released urine. These results suggest that serotonin and noradrenaline reuptake inhibitors exert a strong and effective modulatory effect on the control of urine release and prompt to additional studies on their central effects on brain areas involved in the social and behavioral control of micturition.

Toxicity of chlorpyrifos on some marine cyanobacteria species

International Nuclear Information System (INIS)

Shoaib, N.; Siddiqui, A.; Khalid, H.

2012-01-01

Pakistan is an agricultural country and a wide variety of pesticides are used on its cropland. Pesticides pose serious threats to the natural ecosystem. In the present study cyanobacteria (blue green algae) were used to assess the ecotoxicological effect of chlorpyrifos (organophosphate pesticide). Cyanobacteria are the base of the food web providing food resource to consumers in higher trophic level. Cyanobacteria were isolated and purified from water samples collected from Manora channel. Fast growing cultures of cyanobacteria were used to assess the toxicity of test pesticide . The Light and Dark method was used to determine the primary production of the organisms. The acute toxicity of chlorpyrifos was determined by calculating IC/sub 50/ of the test organisms. The IC/sub 50/ was found to be 0.074, 0.013, 0.08 and 0.3 ppm for Synechocystis aquatilis, Komvophoron minutum, Gloeocapsa crepidinum and Gloeocapsa sanguinea when exposed to chlorpyrifos pesticide . Laboratory experiments with cyanobacteria have demonstrated that organophosphate pesticides are potent inhibitors of photosynthesis. (author)

Fluorescent Chemosensors for Toxic Organophosphorus Pesticides: A Review

Directory of Open Access Journals (Sweden)

Kenneth Fletcher

2010-07-01

Full Text Available Many organophosphorus (OP based compounds are highly toxic and powerful inhibitors of cholinesterases that generate serious environmental and human health concerns. Organothiophosphates with a thiophosphoryl (P=S functional group constitute a broad class of these widely used pesticides. They are related to the more reactive phosphoryl (P=O organophosphates, which include very lethal nerve agents and chemical warfare agents, such as, VX, Soman and Sarin. Unfortunately, widespread and frequent commercial use of OP-based compounds in agricultural lands has resulted in their presence as residues in crops, livestock, and poultry products and also led to their migration into aquifers. Thus, the design of new sensors with improved analyte selectivity and sensitivity is of paramount importance in this area. Herein, we review recent advances in the development of fluorescent chemosensors for toxic OP pesticides and related compounds. We also discuss challenges and progress towards the design of future chemosensors with dual modes for signal transduction.

A CNS-permeable Hsp90 inhibitor rescues synaptic dysfunction and memory loss in APP-overexpressing Alzheimer's mouse model via an HSF1-mediated mechanism.

Science.gov (United States)

Wang, B; Liu, Y; Huang, L; Chen, J; Li, J J; Wang, R; Kim, E; Chen, Y; Justicia, C; Sakata, K; Chen, H; Planas, A; Ostrom, R S; Li, W; Yang, G; McDonald, M P; Chen, R; Heck, D H; Liao, F-F

2017-07-01

Induction of neuroprotective heat-shock proteins via pharmacological Hsp90 inhibitors is currently being investigated as a potential treatment for neurodegenerative diseases. Two major hurdles for therapeutic use of Hsp90 inhibitors are systemic toxicity and limited central nervous system permeability. We demonstrate here that chronic treatment with a proprietary Hsp90 inhibitor compound (OS47720) not only elicits a heat-shock-like response but also offers synaptic protection in symptomatic Tg2576 mice, a model of Alzheimer's disease, without noticeable systemic toxicity. Despite a short half-life of OS47720 in mouse brain, a single intraperitoneal injection induces rapid and long-lasting (>3 days) nuclear activation of the heat-shock factor, HSF1. Mechanistic study indicates that the remedial effects of OS47720 depend upon HSF1 activation and the subsequent HSF1-mediated transcriptional events on synaptic genes. Taken together, this work reveals a novel role of HSF1 in synaptic function and memory, which likely occurs through modulation of the synaptic transcriptome.

NO and H2O2 contribute to SO2 toxicity via Ca2+ signaling in Vicia faba guard cells.

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Yi, Min; Bai, Heli; Xue, Meizhao; Yi, Huilan

2017-04-01

NO and H 2 O 2 have been implicated as important signals in biotic and abiotic stress responses of plants to the environment. Previously, we have shown that SO 2 exposure increased the levels of NO and H 2 O 2 in plant cells. We hypothesize that, as signaling molecules, NO and H 2 O 2 mediate SO 2 -caused toxicity. In this paper, we show that SO 2 hydrates caused guard cell death in a concentration-dependent manner in the concentration range of 0.25 to 6 mmol L -1 , which was associated with elevation of intracellular NO, H 2 O 2 , and Ca 2+ levels in Vicia faba guard cells. NO donor SNP enhanced SO 2 toxicity, while NO scavenger c-PTIO and NO synthesis inhibitors L-NAME and tungstate significantly prevented SO 2 toxicity. ROS scavenger ascorbic acid (AsA) and catalase (CAT), Ca 2+ chelating agent EGTA, and Ca 2+ channel inhibitor LaCl 3 also markedly blocked SO 2 toxicity. In addition, both c-PTIO and AsA could completely block SO 2 -induced elevation of intracellular Ca 2+ level. Moreover, c-PTIO efficiently blocked SO 2 -induced H 2 O 2 elevation, and AsA significantly blocked SO 2 -induced NO elevation. These results indicate that extra NO and H 2 O 2 are produced and accumulated in SO 2 -treated guard cells, which further activate Ca 2+ signaling to mediate SO 2 toxicity. Our findings suggest that both NO and H 2 O 2 contribute to SO 2 toxicity via Ca 2+ signaling.

Reversal of atherogenic lipoprotein profile in HIV-1 infected patients with lipodystrophy after replacing protease inhibitors by nevirapine

NARCIS (Netherlands)

Negredo, Eugenia; Ribalta, Josep; Paredes, Roger; Ferré, Raimón; Sirera, Guillem; Ruiz, Lidia; Salazar, Juliana; Reiss, Peter; Masana, Lluís; Clotet, Bonaventura

2002-01-01

Background: The widespread use of protease inhibitors (PI) has been associated with abnormalities in the lipid profile of HIV-1-infected patients. Treatment simplification approaches in which PI are replaced by nevirapine (NVP) have been shown to improve PI-related toxicity. Objective: To assess the

Cytotoxicity and activation of the Wnt/beta-catenin pathway in mouse embryonic stem cells treated with four GSK3 inhibitors.

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Naujok, Ortwin; Lentes, Jana; Diekmann, Ulf; Davenport, Claudia; Lenzen, Sigurd

2014-04-29

Small membrane-permeable molecules are now widely used during maintenance and differentiation of embryonic stem cells of different species. In particular the glycogen synthase kinase 3 (GSK3) is an interesting target, since its chemical inhibition activates the Wnt/beta-catenin pathway. In the present comparative study four GSK3 inhibitors were characterized. Cytotoxicity and potential to activate the Wnt/beta-catenin pathway were tested using the commonly used GSK3 inhibitors BIO, SB-216763, CHIR-99021, and CHIR-98014. Wnt/beta-catenin-dependent target genes were measured by quantitative PCR to confirm the Wnt-reporter assay and finally EC50-values were calculated. CHIR-99021 and SB-216763 had the lowest toxicities in mouse embryonic stem cells and CHIR-98014 and BIO the highest toxicities. Only CHIR-99021 and CHIR-98014 lead to a strong induction of the Wnt/beta-catenin pathway, whereas BIO and SB-216763 showed a minor or no increase in activation of the Wnt/beta-catenin pathway over the natural ligand Wnt3a. The data from the Wnt-reporter assay were confirmed by gene expression analysis of the TCF/LEF regulated gene T. Out of the four tested GSK3 inhibitors, only CHIR-99021 and CHIR-98014 proved to be potent pharmacological activators of the Wnt/beta-catenin signaling pathway. But only in the case of CHIR-99021 high potency was combined with very low toxicity.

Proteomic analysis of rat cerebral cortex following subchronic acrolein toxicity

Energy Technology Data Exchange (ETDEWEB)

Rashedinia, Marzieh; Lari, Parisa [Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad (Iran, Islamic Republic of); Abnous, Khalil, E-mail: Abnouskh@mums.ac.r [Pharmaceutical Research Center, Department of Medicinal Chemistry, Mashhad University of Medical Sciences, Mashhad (Iran, Islamic Republic of); Hosseinzadeh, Hossein, E-mail: Hosseinzadehh@mums.ac.ir [Pharmaceutical Research Center, Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad (Iran, Islamic Republic of)

2013-10-01

Acrolein, a member of reactive α,β-unsaturated aldehydes, is a major environmental pollutant. Acrolein is also produced endogenously as a toxic by-product of lipid peroxidation. Because of high reactivity, acrolein may mediate oxidative damages to cells and tissues. It has been shown to be involved in a wide variety of pathological states including pulmonary, atherosclerosis and neurodegenerative diseases. In this study we employed proteomics approach to investigate the effects of subchronic oral exposures to 3 mg/kg of acrolein on protein expression profile in the brain of rats. Moreover effects of acrolein on malondialdehyde (MDA) levels and reduced glutathione (GSH) content were investigated. Our results revealed that treatment with acrolein changed levels of several proteins in diverse physiological process including energy metabolism, cell communication and transport, response to stimulus and metabolic process. Interestingly, several differentially over-expressed proteins, including β-synuclein, enolase and calcineurin, are known to be associated with human neurodegenerative diseases. Changes in the levels of some proteins were confirmed by Western blot. Moreover, acrolein increases the level of MDA, as a lipid peroxidation biomarker and decreased GSH concentrations, as a non-enzyme antioxidant in the brain of acrolein treated rats. These findings suggested that acrolein induces the oxidative stress and lipid peroxidation in the brain, and so that may contribute to the pathophysiology of neurological disorders. - Highlights: • Acrolein intoxication increased lipid peroxidation and deplete GSH in rat brain. • Effect of acrolein on protein levels of cerebral cortex was analyzed by 2DE-PAGE. • Levels of a number of proteins with different biological functions were increased.

Proteomic analysis of rat cerebral cortex following subchronic acrolein toxicity

International Nuclear Information System (INIS)

Rashedinia, Marzieh; Lari, Parisa; Abnous, Khalil; Hosseinzadeh, Hossein

2013-01-01

Acrolein, a member of reactive α,β-unsaturated aldehydes, is a major environmental pollutant. Acrolein is also produced endogenously as a toxic by-product of lipid peroxidation. Because of high reactivity, acrolein may mediate oxidative damages to cells and tissues. It has been shown to be involved in a wide variety of pathological states including pulmonary, atherosclerosis and neurodegenerative diseases. In this study we employed proteomics approach to investigate the effects of subchronic oral exposures to 3 mg/kg of acrolein on protein expression profile in the brain of rats. Moreover effects of acrolein on malondialdehyde (MDA) levels and reduced glutathione (GSH) content were investigated. Our results revealed that treatment with acrolein changed levels of several proteins in diverse physiological process including energy metabolism, cell communication and transport, response to stimulus and metabolic process. Interestingly, several differentially over-expressed proteins, including β-synuclein, enolase and calcineurin, are known to be associated with human neurodegenerative diseases. Changes in the levels of some proteins were confirmed by Western blot. Moreover, acrolein increases the level of MDA, as a lipid peroxidation biomarker and decreased GSH concentrations, as a non-enzyme antioxidant in the brain of acrolein treated rats. These findings suggested that acrolein induces the oxidative stress and lipid peroxidation in the brain, and so that may contribute to the pathophysiology of neurological disorders. - Highlights: • Acrolein intoxication increased lipid peroxidation and deplete GSH in rat brain. • Effect of acrolein on protein levels of cerebral cortex was analyzed by 2DE-PAGE. • Levels of a number of proteins with different biological functions were increased

New agents that target senescent cells: the flavone, fisetin, and the BCL-XL inhibitors, A1331852 and A1155463.

Science.gov (United States)

Zhu, Yi; Doornebal, Ewald J; Pirtskhalava, Tamar; Giorgadze, Nino; Wentworth, Mark; Fuhrmann-Stroissnigg, Heike; Niedernhofer, Laura J; Robbins, Paul D; Tchkonia, Tamara; Kirkland, James L

2017-03-08

Senescent cells accumulate with aging and at sites of pathology in multiple chronic diseases. Senolytics are drugs that selectively promote apoptosis of senescent cells by temporarily disabling the pro-survival pathways that enable senescent cells to resist the pro-apoptotic, pro-inflammatory factors that they themselves secrete. Reducing senescent cell burden by genetic approaches or by administering senolytics delays or alleviates multiple age- and disease-related adverse phenotypes in preclinical models. Reported senolytics include dasatinib, quercetin, navitoclax (ABT263), and piperlongumine. Here we report that fisetin, a naturally-occurring flavone with low toxicity, and A1331852 and A1155463, selective BCL-X L inhibitors that may have less hematological toxicity than the less specific BCL-2 family inhibitor navitoclax, are senolytic. Fisetin selectively induces apoptosis in senescent but not proliferating human umbilical vein endothelial cells (HUVECs). It is not senolytic in senescent IMR90 cells, a human lung fibroblast strain, or primary human preadipocytes. A1331852 and A1155463 are senolytic in HUVECs and IMR90 cells, but not preadipocytes. These agents may be better candidates for eventual translation into clinical interventions than some existing senolytics, such as navitoclax, which is associated with hematological toxicity.

The Effects of Piroxicam in the Attenuation of MPP+/MPTP Toxicity In Vitro and In Vivo

Science.gov (United States)

Soliman, Y.; Jackson, T.; Mazzio, E.

2010-01-01

Several lines of evidence support the neuroprotective action of cyclooxygenase-2 (COX-2) inhibitors in various models of Parkinson's disease (PD). In the current study, we investigated the neuroprotective properties of several COX inhibitors against 1-methyl-4-phenylpyridinium (MPP+) in neuroblastoma Neuro 2A (N-2A) cells in vitro and the protection against degeneration of substantia nigra pars compacta (SNc) dopaminergic (DA) neurons after the administration of 1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine (MPTP) in C57/BL6 male mice. The data obtained demonstrate a lack of protective effects observed by COX 1-2 inhibitors ibuprofen and acetylsalicylic acid against MPP+ toxicity in N-2A, where piroxicam was protective in a dose dependent manner (MPP+ control: 15 ± 2% MPP+ piroxicam: 5 mM 89 ± 4%). The data also indicate a drop in mitochondrial oxygen (O2) consumption and ATP during MPP+ toxicity with no restoration of mitochondrial function concurrent to a heightened concentration of somatic ATP during piroxicam rescue. These findings indicate that the neuroprotective effects of COX inhibitors against MPP+ are not consistent, but that piroxicam may work through an unique mechanism to propel anaerobic energy metabolism. On the other hand, using mice, piroxicam (20 mg/kg) was effective against MPTP-induced dopaminergic degeneration in the (SNc) and loss of locomotive function in mice. Administering a 3 day pre-treatment of piroxicam (20 mg/kg) was effective in antagonizing the losses in SNc tyrosine hydroxylase protein expression, SNc DA concentration and associated anomaly in ambulatory locomotor activity. It was concluded from these findings that piroxicam is unique among COX inhibitors in providing very significant neuroprotection against MPP+ in vitro and in vivo. PMID:18612814

Genetic and chemical modifiers of a CUG toxicity model in Drosophila.

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Amparo Garcia-Lopez

2008-02-01

Full Text Available Non-coding CUG repeat expansions interfere with the activity of human Muscleblind-like (MBNL proteins contributing to myotonic dystrophy 1 (DM1. To understand this toxic RNA gain-of-function mechanism we developed a Drosophila model expressing 60 pure and 480 interrupted CUG repeats in the context of a non-translatable RNA. These flies reproduced aspects of the DM1 pathology, most notably nuclear accumulation of CUG transcripts, muscle degeneration, splicing misregulation, and diminished Muscleblind function in vivo. Reduced Muscleblind activity was evident from the sensitivity of CUG-induced phenotypes to a decrease in muscleblind genetic dosage and rescue by MBNL1 expression, and further supported by the co-localization of Muscleblind and CUG repeat RNA in ribonuclear foci. Targeted expression of CUG repeats to the developing eye and brain mushroom bodies was toxic leading to rough eyes and semilethality, respectively. These phenotypes were utilized to identify genetic and chemical modifiers of the CUG-induced toxicity. 15 genetic modifiers of the rough eye phenotype were isolated. These genes identify putative cellular processes unknown to be altered by CUG repeat RNA, and they include mRNA export factor Aly, apoptosis inhibitor Thread, chromatin remodelling factor Nurf-38, and extracellular matrix structural component Viking. Ten chemical compounds suppressed the semilethal phenotype. These compounds significantly improved viability of CUG expressing flies and included non-steroidal anti-inflammatory agents (ketoprofen, muscarinic, cholinergic and histamine receptor inhibitors (orphenadrine, and drugs that can affect sodium and calcium metabolism such as clenbuterol and spironolactone. These findings provide new insights into the DM1 phenotype, and suggest novel candidates for DM1 treatments.

Cyclosporin versus tacrolimus for liver transplanted patients

DEFF Research Database (Denmark)

Haddad, E M; McAlister, V C; Renouf, E

2006-01-01

Most liver transplant recipients receive either cyclosporin or tacrolimus to prevent rejection. Both drugs inhibit calcineurin phosphatase which is thought to be the mechanism of their anti-rejection effect and principle toxicities. The drugs have different pharmacokinetic profiles and potencies....... Several randomised clinical trials have compared cyclosporin and tacrolimus in liver transplant recipients, but it remains unclear which is superior....

ARTERIAL HYPERTENSION DURING THERAPY OF ONCOLOGICAL DISEASES WITH ANGIOGENESIS INHIBITORS: SERIOUS IMPEDIMENT OR CONTROLLED REACTION?

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Zh. D. Kobalava

2017-01-01

Full Text Available Vascular endothelial growth factor signaling pathway (VSP inhibitors are drugs for which arterial hypertension (AH is a class effect, occurring with a frequency of up to 73 % of treated patients. Blockade of vascular endothelial growth factor or its receptor is accompanied by inhibition of the synthesis of nitric oxide, which is considered a major pathogenic mechanism for the development of AH. VSP-inhibitors therapy will be as safe as possible, if the patient prior to treatment will take a minimum assessment, allowing to identify the category of patients with high/very high cardiovascular risk. Risk evaluation is necessary not to abandon an effective therapy of VSP-inhibitors, and to provide a systematic approach to reduce the likelihood of potential cardiovascular toxicity. Blood pressure during VSP-inhibitors therapy is characterized by a rapid rise after the first dose of target therapy, as a rule, in the first cycle of treatment, ranging from no increase to double the systolic blood pressure. Usually iatrogenic AH spontaneously resolves after stopping chemotherapy. Timely prescribed antihypertensive therapy help to avoids dose reduction or interruption of the course of VSP-inhibitors, which significantly improves the survival of patients.

Discovery and characterization of a potent and selective inhibitor of Aedes aegypti inward rectifier potassium channels.

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Rene Raphemot

Full Text Available Vector-borne diseases such as dengue fever and malaria, which are transmitted by infected female mosquitoes, affect nearly half of the world's population. The emergence of insecticide-resistant mosquito populations is reducing the effectiveness of conventional insecticides and threatening current vector control strategies, which has created an urgent need to identify new molecular targets against which novel classes of insecticides can be developed. We previously demonstrated that small molecule inhibitors of mammalian Kir channels represent promising chemicals for new mosquitocide development. In this study, high-throughput screening of approximately 30,000 chemically diverse small-molecules was employed to discover potent and selective inhibitors of Aedes aegypti Kir1 (AeKir1 channels heterologously expressed in HEK293 cells. Of 283 confirmed screening 'hits', the small-molecule inhibitor VU625 was selected for lead optimization and in vivo studies based on its potency and selectivity toward AeKir1, and tractability for medicinal chemistry. In patch clamp electrophysiology experiments of HEK293 cells, VU625 inhibits AeKir1 with an IC50 value of 96.8 nM, making VU625 the most potent inhibitor of AeKir1 described to date. Furthermore, electrophysiology experiments in Xenopus oocytes revealed that VU625 is a weak inhibitor of AeKir2B. Surprisingly, injection of VU625 failed to elicit significant effects on mosquito behavior, urine excretion, or survival. However, when co-injected with probenecid, VU625 inhibited the excretory capacity of mosquitoes and was toxic, suggesting that the compound is a substrate of organic anion and/or ATP-binding cassette (ABC transporters. The dose-toxicity relationship of VU625 (when co-injected with probenecid is biphasic, which is consistent with the molecule inhibiting both AeKir1 and AeKir2B with different potencies. This study demonstrates proof-of-concept that potent and highly selective inhibitors of mosquito

Novel approaches to mitigating parathion toxicity: targeting cytochrome P450–mediated metabolism with menadione

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Jan, Yi-Hua; Richardson, Jason R.; Baker, Angela A.; Mishin, Vladimir; Heck, Diane E.; Laskin, Debra L.; Laskin, Jeffrey D.

2016-01-01

Accidental or intentional exposures to parathion, an organophosphorus (OP) pesticide, can cause severe poisoning in humans. Parathion toxicity is dependent on its metabolism by the cytochrome P450 (CYP) system to paraoxon (diethyl 4-nitrophenyl phosphate), a highly poisonous nerve agent and potent inhibitor of acetylcholinesterase (AChE). We have been investigating inhibitors of CYP-mediated bioactivation of OPs as a method of preventing or reversing progressive parathion toxicity. It is well recognized that NADPH–cytochrome P450 reductase, an enzyme required for the transfer of electrons to CYPs, mediates chemical redox cycling. In this process, the enzyme diverts electrons from CYPs to support chemical redox cycling, which results in inhibition of CYP-mediated biotransformation. Using menadione as the redox-cycling chemical, we discovered that this enzymatic reaction blocks metabolic activation of parathion in rat and human liver microsomes and in recombinant CYPs important to parathion metabolism, including CYP1A2, CYP2B6, and CYP3A4. Administration of menadione to rats reduces metabolism of parathion, as well as parathion-induced inhibition of brain cholinesterase activity. This resulted in inhibition of parathion neurotoxicity. Menadione has relatively low toxicity and is approved by the FDA for other indications. Its ability to block parathion metabolism makes it an attractive therapeutic candidate to mitigate parathion-induced neurotoxicity. PMID:27441453

Crystallization and preliminary crystallographic analysis of the human calcineurin homologous protein CHP2 bound to the cytoplasmic region of the Na+/H+ exchanger NHE1

International Nuclear Information System (INIS)

Ben Ammar, Youssef; Takeda, Soichi; Sugawara, Mitsuaki; Miyano, Masashi; Mori, Hidezo; Wakabayashi, Shigeo

2005-01-01

Crystallization of the human CHP2–NHE1 binding domain complex. Calcineurin homologous protein (CHP) is a Ca 2+ -binding protein that directly interacts with and regulates the activity of all plasma-membrane Na + /H + -exchanger (NHE) family members. In contrast to the ubiquitous isoform CHP1, CHP2 is highly expressed in cancer cells. To understand the regulatory mechanism of NHE1 by CHP2, the complex CHP2–NHE1 (amino acids 503–545) has been crystallized by the sitting-drop vapour-diffusion method using PEG 3350 as precipitant. The crystals diffract to 2.7 Å and belong to a tetragonal space group, with unit-cell parameters a = b = 49.96, c = 103.20 Å

Ibrutinib synergizes with poly(ADP-ribose) glycohydrolase inhibitors to induce cell death in AML cells via a BTK-independent mechanism.

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Rotin, Lianne E; Gronda, Marcela; MacLean, Neil; Hurren, Rose; Wang, XiaoMing; Lin, Feng-Hsu; Wrana, Jeff; Datti, Alessandro; Barber, Dwayne L; Minden, Mark D; Slassi, Malik; Schimmer, Aaron D

2016-01-19

Targeting Bruton's tyrosine kinase (BTK) with the small molecule BTK inhibitor ibrutinib has significantly improved patient outcomes in several B-cell malignancies, with minimal toxicity. Given the reported expression and constitutive activation of BTK in acute myeloid leukemia (AML) cells, there has been recent interest in investigating the anti-AML activity of ibrutinib. We noted that ibrutinib had limited single-agent toxicity in a panel of AML cell lines and primary AML samples, and therefore sought to identify ibrutinib-sensitizing drugs. Using a high-throughput combination chemical screen, we identified that the poly(ADP-ribose) glycohydrolase (PARG) inhibitor ethacridine lactate synergized with ibrutinib in TEX and OCI-AML2 leukemia cell lines. The combination of ibrutinib and ethacridine induced a synergistic increase in reactive oxygen species that was functionally important to explain the observed cell death. Interestingly, synergistic cytotoxicity of ibrutinib and ethacridine was independent of the inhibitory effect of ibrutinib against BTK, as knockdown of BTK did not sensitize TEX and OCI-AML2 cells to ethacridine treatment. Thus, our findings indicate that ibrutinib may have a BTK-independent role in AML and that PARG inhibitors may have utility as part of a combination therapy for this disease.

Mechanism of Action of Thalassospiramides, A New Class of Calpain Inhibitors

KAUST Repository

Lu, Liang

2015-03-05

Thalassospiramides comprise a large family of lipopeptide natural products produced by Thalassospira and Tistrella marine bacteria. Here we provide further evidence of their nanomolar inhibitory activity against the human calpain 1 protease. Analysis of structure-activity relationship data supported our hypothesis that the rigid 12-membered ring containing an α,β-unsaturated carbonyl moiety is the pharmacologically active functional group, in contrast to classic electrophilic "warheads" in known calpain inhibitors. Using a combination of chemical modifications, mass spectrometric techniques, site-directed mutagenesis, and molecular modeling, we show the covalent binding of thalassospiramide\\'s α,β-unsaturated carbonyl moiety to the thiol group of calpain\\'s catalytic Cys115 residue by a Michael 1,4-addition reaction. As nanomolar calpain inhibitors with promising selectivity and low toxicity from natural sources are rare, we consider thalassospiramides as promising drug leads.

Mechanism of Action of Thalassospiramides, A New Class of Calpain Inhibitors

KAUST Repository

Lu, Liang; Meehan, Michael J.; Gu, Shuo; Chen, Zhilong; Zhang, Weipeng; Zhang, Gen; Liu, Lingli; Huang, Xuhui; Dorrestein, Pieter C.; Xu, Ying; Moore, Bradley S.; Qian, Pei-Yuan

2015-01-01

Thalassospiramides comprise a large family of lipopeptide natural products produced by Thalassospira and Tistrella marine bacteria. Here we provide further evidence of their nanomolar inhibitory activity against the human calpain 1 protease. Analysis of structure-activity relationship data supported our hypothesis that the rigid 12-membered ring containing an α,β-unsaturated carbonyl moiety is the pharmacologically active functional group, in contrast to classic electrophilic "warheads" in known calpain inhibitors. Using a combination of chemical modifications, mass spectrometric techniques, site-directed mutagenesis, and molecular modeling, we show the covalent binding of thalassospiramide's α,β-unsaturated carbonyl moiety to the thiol group of calpain's catalytic Cys115 residue by a Michael 1,4-addition reaction. As nanomolar calpain inhibitors with promising selectivity and low toxicity from natural sources are rare, we consider thalassospiramides as promising drug leads.

Transcriptional Profiling of Hypoxic Neural Stem Cells Identifies Calcineurin-NFATc4 Signaling as a Major Regulator of Neural Stem Cell Biology

Science.gov (United States)

Moreno, Marta; Fernández, Virginia; Monllau, Josep M.; Borrell, Víctor; Lerin, Carles; de la Iglesia, Núria

2015-01-01

Summary Neural stem cells (NSCs) reside in a hypoxic microenvironment within the brain. However, the crucial transcription factors (TFs) that regulate NSC biology under physiologic hypoxia are poorly understood. Here we have performed gene set enrichment analysis (GSEA) of microarray datasets from hypoxic versus normoxic NSCs with the aim of identifying pathways and TFs that are activated under oxygen concentrations mimicking normal brain tissue microenvironment. Integration of TF target (TFT) and pathway enrichment analysis identified the calcium-regulated TF NFATc4 as a major candidate to regulate hypoxic NSC functions. Nfatc4 expression was coordinately upregulated by top hypoxia-activated TFs, while NFATc4 target genes were enriched in hypoxic NSCs. Loss-of-function analyses further revealed that the calcineurin-NFATc4 signaling axis acts as a major regulator of NSC self-renewal and proliferation in vitro and in vivo by promoting the expression of TFs, including Id2, that contribute to the maintenance of the NSC state. PMID:26235896

Regulation of the Na+/K+-ATPase Ena1 Expression by Calcineurin/Crz1 under High pH Stress: A Quantitative Study.

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Silvia Petrezsélyová

Full Text Available Regulated expression of the Ena1 Na+-ATPase is a crucial event for adaptation to high salt and/or alkaline pH stress in the budding yeast Saccharomyces cerevisiae. ENA1 expression is under the control of diverse signaling pathways, including that mediated by the calcium-regulatable protein phosphatase calcineurin and its downstream transcription factor Crz1. We present here a quantitative study of the expression of Ena1 in response to alkalinization of the environment and we analyze the contribution of Crz1 to this response. Experimental data and mathematical models substantiate the existence of two stress-responsive Crz1-binding sites in the ENA1 promoter and estimate that the contribution of Crz1 to the early response of the ENA1 promoter is about 60%. The models suggest the existence of a second input with similar kinetics, which would be likely mediated by high pH-induced activation of the Snf1 kinase.

Presynaptic Dopamine D2 Receptors Modulate [3H]GABA Release at StriatoPallidal Terminals via Activation of PLC → IP3 → Calcineurin and Inhibition of AC → cAMP → PKA Signaling Cascades.

Science.gov (United States)

Jijón-Lorenzo, Rafael; Caballero-Florán, Isaac Hiram; Recillas-Morales, Sergio; Cortés, Hernán; Avalos-Fuentes, José Arturo; Paz-Bermúdez, Francisco Javier; Erlij, David; Florán, Benjamín

2018-02-21

Striatal dopamine D2 receptors activate the PLC → IP3 → Calcineurin-signaling pathway to modulate the neural excitability of En+ Medium-sized Spiny GABAergic neurons (MSN) through the regulation of L-type Ca 2+ channels. Presynaptic dopaminergic D2 receptors modulate GABA release at striatopallidal terminals through L-type Ca 2+ channels as well, but their signaling pathway is still undetermined. Since D2 receptors are Gi/o-coupled and negatively modulate adenylyl cyclase (AC), we investigated whether presynaptic D2 receptors modulate GABA release through the same signaling cascade that controls excitability in the striatum or by the inhibition of AC and decreased PKA activity. Activation of D2 receptors stimulated formation of [ 3 H]IP 1 and decreased Forskolin-stimulated [ 3 H]cAMP accumulation in synaptosomes from rat Globus Pallidus. D2 receptor activation with Quinpirole in the presence of L 745,870 decreased, in a dose-dependent manner, K + -induced [ 3 H]GABA release in pallidal slices. The effect was prevented by the pharmacological blockade of Gi/o βγ subunit effects with Gallein, PLC with U 73122, IP3 receptor activation with 4-APB, Calcineurin with FK506. In addition, when release was stimulated with Forskolin to activate AC, D2 receptors also decreased K + -induced [ 3 H]GABA release, an effect occluded with the effect of the blockade of PKA with H89 or stimulation of release with the cAMP analog 8-Br-cAMP. These data indicate that D2 receptors modulate [ 3 H]GABA release at striatopallidal terminals by activating the PLC → IP3 → Calcineurin-signaling cascade, the same one that modulates excitability in soma. Additionally, D2 receptors inhibit release when AC is active. Both mechanisms appear to converge to regulate the activity of presynaptic L-type Ca 2+ channels. Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.

Delayed Toxicity Associated with Soluble Anthrax Toxin Receptor Decoy-Ig Fusion Protein Treatment

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Cote, Christopher; Welkos, Susan; Manchester, Marianne; Young, John A. T.

2012-01-01

Soluble receptor decoy inhibitors, including receptor-immunogloubulin (Ig) fusion proteins, have shown promise as candidate anthrax toxin therapeutics. These agents act by binding to the receptor-interaction site on the protective antigen (PA) toxin subunit, thereby blocking toxin binding to cell surface receptors. Here we have made the surprising observation that co-administration of receptor decoy-Ig fusion proteins significantly delayed, but did not protect, rats challenged with anthrax lethal toxin. The delayed toxicity was associated with the in vivo assembly of a long-lived complex comprised of anthrax lethal toxin and the receptor decoy-Ig inhibitor. Intoxication in this system presumably results from the slow dissociation of the toxin complex from the inhibitor following their prolonged circulation. We conclude that while receptor decoy-Ig proteins represent promising candidates for the early treatment of B. anthracis infection, they may not be suitable for therapeutic use at later stages when fatal levels of toxin have already accumulated in the bloodstream. PMID:22511955

Chemical Proteomics Reveals Ferrochelatase as a Common Off-target of Kinase Inhibitors.

Science.gov (United States)

Klaeger, Susan; Gohlke, Bjoern; Perrin, Jessica; Gupta, Vipul; Heinzlmeir, Stephanie; Helm, Dominic; Qiao, Huichao; Bergamini, Giovanna; Handa, Hiroshi; Savitski, Mikhail M; Bantscheff, Marcus; Médard, Guillaume; Preissner, Robert; Kuster, Bernhard

2016-05-20

Many protein kinases are valid drug targets in oncology because they are key components of signal transduction pathways. The number of clinical kinase inhibitors is on the rise, but these molecules often exhibit polypharmacology, potentially eliciting desired and toxic effects. Therefore, a comprehensive assessment of a compound's target space is desirable for a better understanding of its biological effects. The enzyme ferrochelatase (FECH) catalyzes the conversion of protoporphyrin IX into heme and was recently found to be an off-target of the BRAF inhibitor Vemurafenib, likely explaining the phototoxicity associated with this drug in melanoma patients. This raises the question of whether FECH binding is a more general feature of kinase inhibitors. To address this, we applied a chemical proteomics approach using kinobeads to evaluate 226 clinical kinase inhibitors for their ability to bind FECH. Surprisingly, low or submicromolar FECH binding was detected for 29 of all compounds tested and isothermal dose response measurements confirmed target engagement in cells. We also show that Vemurafenib, Linsitinib, Neratinib, and MK-2461 reduce heme levels in K562 cells, verifying that drug binding leads to a loss of FECH activity. Further biochemical and docking experiments identified the protoporphyrin pocket in FECH as one major drug binding site. Since the genetic loss of FECH activity leads to photosensitivity in humans, our data strongly suggest that FECH inhibition by kinase inhibitors is the molecular mechanism triggering photosensitivity in patients. We therefore suggest that a FECH assay should generally be part of the preclinical molecular toxicology package for the development of kinase inhibitors.

Discorhabdin P, a new enzyme inhibitor from a deep-water Caribbean sponge of the genus Batzella.

Science.gov (United States)

Gunasekera, S P; McCarthy, P J; Longley, R E; Pomponi, S A; Wright, A E; Lobkovsky, E; Clardy, J

1999-01-01

Discorhabdin P (1), a new discorhabdin analogue, has been isolated from a deep-water marine sponge of the genus Batzella. Discorhabdin P (1) inhibited the phosphatase activity of calcineurin and the peptidase activity of CPP32. It also showed in vitro cytotoxicity against P-388 and A-549 cell lines. The isolation and structure elucidation of discorhabdin P (1) are described.

A randomized trial comparing initial HAART regimens of nelfinavir/nevirapine and ritonavir/saquinavir in combination with two nucleoside reverse transcriptase inhibitors

DEFF Research Database (Denmark)

Kirk, Ole; Lundgren, Jens D; Pedersen, Court

2003-01-01

BACKGROUND: A triple-class HAART regimen may be associated with a better virological effect than conventional regimens, but may also lead to toxicity and more profound resistance. METHODS: Randomized, controlled, open-label trial of 233 protease inhibitor- and non-nucleoside reverse transcriptase...... inhibitor-naive HIV-infected patients allocated to a regimen of nelfinavir and nevirapine (1250/200 mg twice daily; n = 118) or ritonavir and saquinavir (400/400 mg twice daily; n = 115), both in combination with two nucleoside reverse transcriptase inhibitors. The primary end-point was HIV RNA ... the long-term consequences of triple class HAART regimens, including the development of broad drug resistance....

Small molecule inhibitors uncover synthetic genetic interactions of human flap endonuclease 1 (FEN1 with DNA damage response genes.

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Thomas A Ward

Full Text Available Flap endonuclease 1 (FEN1 is a structure selective endonuclease required for proficient DNA replication and the repair of DNA damage. Cellularly active inhibitors of this enzyme have previously been shown to induce a DNA damage response and, ultimately, cell death. High-throughput screens of human cancer cell-lines identify colorectal and gastric cell-lines with microsatellite instability (MSI as enriched for cellular sensitivity to N-hydroxyurea series inhibitors of FEN1, but not the PARP inhibitor olaparib or other inhibitors of the DNA damage response. This sensitivity is due to a synthetic lethal interaction between FEN1 and MRE11A, which is often mutated in MSI cancers through instabilities at a poly(T microsatellite repeat. Disruption of ATM is similarly synthetic lethal with FEN1 inhibition, suggesting that disruption of FEN1 function leads to the accumulation of DNA double-strand breaks. These are likely a result of the accumulation of aberrant replication forks, that accumulate as a consequence of a failure in Okazaki fragment maturation, as inhibition of FEN1 is toxic in cells disrupted for the Fanconi anemia pathway and post-replication repair. Furthermore, RAD51 foci accumulate as a consequence of FEN1 inhibition and the toxicity of FEN1 inhibitors increases in cells disrupted for the homologous recombination pathway, suggesting a role for homologous recombination in the resolution of damage induced by FEN1 inhibition. Finally, FEN1 appears to be required for the repair of damage induced by olaparib and cisplatin within the Fanconi anemia pathway, and may play a role in the repair of damage associated with its own disruption.

Differential transcript profile of inhibitors with potential anti-venom role in the liver of juvenile and adult Bothrops jararaca snake

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Cícera Maria Gomes

2017-04-01

Full Text Available Background Snakes belonging to the Bothrops genus are vastly distributed in Central and South America and are responsible for most cases of reported snake bites in Latin America. The clinical manifestations of the envenomation caused by this genus are due to three major activities—proteolytic, hemorrhagic and coagulant—mediated by metalloproteinases, serine proteinases, phospholipases A2 and other toxic compounds present in snake venom. Interestingly, it was observed that snakes are resistant to the toxic effects of its own and other snake’s venoms. This natural immunity may occur due the absence of toxin target or the presence of molecules in the snake plasma able to neutralize such toxins. Methods In order to identify anti-venom molecules, we construct a cDNA library from the liver of B. jararaca snakes. Moreover, we analyzed the expression profile of four molecules—the already known anti-hemorrhagic factor Bj46a, one gamma-phospholipase A2 inhibitor, one inter-alpha inhibitor and one C1 plasma protease inhibitor—in the liver of juvenile and adult snakes by qPCR. Results The results revealed a 30-fold increase of gamma-phospholipase A2 inhibitor and a minor increase of the inter-alpha inhibitor (5-fold and of the C1 inhibitor (3-fold in adults. However, the Bj46a factor seems to be equally transcribed in adults and juveniles. Discussion The results suggest the up-regulation of different inhibitors observed in the adult snakes might be a physiological adaptation to the recurrent contact with their own and even other snake’s venoms throughout its lifespan. This is the first comparative analysis of ontogenetic variation of expression profiles of plasmatic proteins with potential anti-venom activities of the venomous snake B. jararaca. Furthermore, the present data contributes to the understanding of the natural resistance described in these snakes.

Fatty acid transport protein-2 inhibitor Grassofermata/CB5 protects cells against lipid accumulation and toxicity

Energy Technology Data Exchange (ETDEWEB)

Saini, Nipun; Black, Paul N.; Montefusco, David; DiRusso, Concetta C., E-mail: cdirusso2@unl.edu

2015-09-25

The inhibition of the fatty acid uptake into non-adipose tissues provides an attractive target for prevention of lipotoxicity leading to obesity-associated non-alcoholic fatty liver disease and type 2 diabetes. Fatty acid transport proteins (FATPs) are bifunctional proteins involved in the uptake and activation of fatty acids by esterification with coenzyme A. Here we characterize Grassofermata/CB5, previously identified as a fatty acid uptake inhibitor directed against HsFATP2. The compound was effective in inhibiting the uptake of fatty acids in the low micro-molar range (IC{sub 50} 8–11 μM) and prevented palmitate-mediated lipid accumulation and cell death in cell lines that are models for intestines, liver, muscle and pancreas. In adipocytes, uptake inhibition was less effective (IC{sub 50} 58 μM). Inhibition was specific for long chain fatty acids and was ineffective toward medium chain fatty acids, which are transported by diffusion. Kinetic analysis of Grassofermata-dependent FA transport inhibition verified a non-competitive mechanism. By comparison with Grassofermata, several atypical antipsychotic drugs previously implicated as inhibitors of FA uptake were ineffectual. In mice Grassofermata decreased absorption of {sup 13}C-oleate demonstrating its potential as a therapeutic agent. - Highlights: • Grassofermata is a small compound inhibitor of FATP2. • Uptake inhibition is specific for long chain fatty acids. • Uptake kinetics shows low specificity for adipocytes compared to other cell types. • Inhibition is by a non-competitive mechanism. • Atypical antipsychotics do not inhibit FA uptake by comparison with Grassofermata.

Fatty acid transport protein-2 inhibitor Grassofermata/CB5 protects cells against lipid accumulation and toxicity

International Nuclear Information System (INIS)

Saini, Nipun; Black, Paul N.; Montefusco, David; DiRusso, Concetta C.

2015-01-01

The inhibition of the fatty acid uptake into non-adipose tissues provides an attractive target for prevention of lipotoxicity leading to obesity-associated non-alcoholic fatty liver disease and type 2 diabetes. Fatty acid transport proteins (FATPs) are bifunctional proteins involved in the uptake and activation of fatty acids by esterification with coenzyme A. Here we characterize Grassofermata/CB5, previously identified as a fatty acid uptake inhibitor directed against HsFATP2. The compound was effective in inhibiting the uptake of fatty acids in the low micro-molar range (IC 50 8–11 μM) and prevented palmitate-mediated lipid accumulation and cell death in cell lines that are models for intestines, liver, muscle and pancreas. In adipocytes, uptake inhibition was less effective (IC 50 58 μM). Inhibition was specific for long chain fatty acids and was ineffective toward medium chain fatty acids, which are transported by diffusion. Kinetic analysis of Grassofermata-dependent FA transport inhibition verified a non-competitive mechanism. By comparison with Grassofermata, several atypical antipsychotic drugs previously implicated as inhibitors of FA uptake were ineffectual. In mice Grassofermata decreased absorption of 13 C-oleate demonstrating its potential as a therapeutic agent. - Highlights: • Grassofermata is a small compound inhibitor of FATP2. • Uptake inhibition is specific for long chain fatty acids. • Uptake kinetics shows low specificity for adipocytes compared to other cell types. • Inhibition is by a non-competitive mechanism. • Atypical antipsychotics do not inhibit FA uptake by comparison with Grassofermata

RCAN1.4 regulates VEGFR-2 internalisation, cell polarity and migration in human microvascular endothelial cells.

Science.gov (United States)

Alghanem, Ahmad F; Wilkinson, Emma L; Emmett, Maxine S; Aljasir, Mohammad A; Holmes, Katherine; Rothermel, Beverley A; Simms, Victoria A; Heath, Victoria L; Cross, Michael J

2017-08-01

Regulator of calcineurin 1 (RCAN1) is an endogenous inhibitor of the calcineurin pathway in cells. It is expressed as two isoforms in vertebrates: RCAN1.1 is constitutively expressed in most tissues, whereas transcription of RCAN1.4 is induced by several stimuli that activate the calcineurin-NFAT pathway. RCAN1.4 is highly upregulated in response to VEGF in human endothelial cells in contrast to RCAN1.1 and is essential for efficient endothelial cell migration and tubular morphogenesis. Here, we show that RCAN1.4 has a role in the regulation of agonist-stimulated VEGFR-2 internalisation and establishment of endothelial cell polarity. siRNA-mediated gene silencing revealed that RCAN1 plays a vital role in regulating VEGF-mediated cytoskeletal reorganisation and directed cell migration and sprouting angiogenesis. Adenoviral-mediated overexpression of RCAN1.4 resulted in increased endothelial cell migration. Antisense-mediated morpholino silencing of the zebrafish RCAN1.4 orthologue revealed a disrupted vascular development further confirming a role for the RCAN1.4 isoform in regulating vascular endothelial cell physiology. Our data suggest that RCAN1.4 plays a novel role in regulating endothelial cell migration by establishing endothelial cell polarity in response to VEGF.

Effect of Toxicants on Fatty Acid Metabolism in HepG2 Cells

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David Grünig

2018-04-01

Full Text Available Impairment of hepatic fatty acid metabolism can lead to liver steatosis and injury. Testing drugs for interference with hepatic fatty acid metabolism is therefore important. To find out whether HepG2 cells are suitable for this purpose, we investigated the effect of three established fatty acid metabolism inhibitors and of three test compounds on triglyceride accumulation, palmitate metabolism, the acylcarnitine pool and dicarboxylic acid accumulation in the cell supernatant and on ApoB-100 excretion in HepG2 cells. The three established inhibitors [etomoxir, methylenecyclopropylacetic acid (MCPA, and 4-bromocrotonic acid (4-BCA] depleted mitochondrial ATP at lower concentrations than cytotoxicity occurred, suggesting mitochondrial toxicity. They inhibited palmitate metabolism at similar or lower concentrations than ATP depletion, and 4-BCA was associated with cellular fat accumulation. They caused specific changes in the acylcarnitine pattern and etomoxir an increase of thapsic (C18 dicarboxylic acid in the cell supernatant, and did not interfere with ApoB-100 excretion (marker of VLDL export. The three test compounds (amiodarone, tamoxifen, and the cannabinoid WIN 55,212-2 depleted the cellular ATP content at lower concentrations than cytotoxicity occurred. They all caused cellular fat accumulation and inhibited palmitate metabolism at similar or higher concentrations than ATP depletion. They suppressed medium-chain acylcarnitines in the cell supernatant and amiodarone and tamoxifen impaired thapsic acid production. Tamoxifen and WIN 55,212-2 decreased cellular ApoB-100 excretion. In conclusion, the established inhibitors of fatty acid metabolism caused the expected effects in HepG2 cells. HepG cells proved to be useful for the detection of drug-associated toxicities on hepatocellular fatty acid metabolism.

The Role of Biomarkers in Decreasing Risk of Cardiac Toxicity after Cancer Therapy

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Christine Henri

2016-01-01

Full Text Available With the improvement of cancer therapy, survival related to malignancy has improved, but the prevalence of long-term cardiotoxicity has also increased. Cancer therapies with known cardiac toxicity include anthracyclines, biologic agents (trastuzumab, and multikinase inhibitors (sunitinib. The most frequent presentation of cardiac toxicity is dilated cardiomyopathy associated with poorest prognosis. Monitoring of cardiac toxicity is commonly performed by assessment of left ventricular (LV ejection fraction, which requires a significant amount of myocardial damage to allow detection of cardiac toxicity. Accordingly, this creates the impetus to search for more sensitive and reproducible biomarkers of cardiac toxicity after cancer therapy. Different biomarkers have been proposed to that end, the most studied ones included troponin release resulting from cardiomyocyte damage and natriuretic peptides reflecting elevation in LV filling pressure and wall stress. Increase in the levels of troponin and natriuretic peptides have been correlated with cumulative dose of anthracycline and the degree of LV dysfunction. Troponin is recognized as a highly efficient predictor of early and chronic cardiac toxicity, but there remains some debate regarding the clinical usefulness of the measurement of natriuretic peptides because of divergent results. Preliminary data are available for other biomarkers targeting inflammation, endothelial dysfunction, myocardial ischemia, and neuregulin-1. The purpose of this article is to review the available data to determine the role of biomarkers in decreasing the risk of cardiac toxicity after cancer therapy.

Effects of various nitric oxide synthase inhibitors on AlCl3-induced neuronal injury in rats

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IVANA STEVANOVIĆ

2009-05-01

Full Text Available The present study was aimed at determining the effectiveness of nitric oxide synthase (NOS inhibitors: N-nitro-L-arginine methyl ester, 7-nitroindazole and aminoguanidine in modulating the toxicity of AlCl3 on superoxide production and the malondialdehyde concentration of Wistar rats. The animals were sacrificed 10 min and 3 days after the treatment and the forebrain cortex was removed. The results show that AlCl3 exposure promotes oxidative stress in different neural areas. The biochemical changes observed in the neuronal tissues show that aluminum acts as pro-oxidant, while NOS inhibitors exert an anti-oxidant action in AlCl3-treated animals.

Study of Plant Cordia Dichotoma as Green Corrosion Inhibitor for Mild Steel in Different Acid Media

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R. Khandelwal

2011-01-01

Full Text Available The corrosion inhibition of mild steel using extracts of Cordia dichotoma in different acid media was investigated by mass loss and thermometric methods. The experiments were carried out at 299±0.2 K in presence of different concentrations of dry fruit, leaves and stem extracts of Cordia dichotoma. The results reveal that the alcoholic extracts of Cordia dichotoma is a better corrosion inhibitor than that of toxic chemicals. The fruit extract is more potent than leaves and stem extracts to inhibit the corrosion rate. The study seeks to investigate the possibility of using extracts of Cordia dichotoma as a green corrosion inhibitor for mild steel.

Everolimus initiation and early calcineurin inhibitor withdrawal in heart transplant recipients

DEFF Research Database (Denmark)

Andreassen, A K; Andersson, B; Gustafsson, F

2014-01-01

In a randomized, open-label trial, everolimus was compared to cyclosporine in 115 de novo heart transplant recipients. Patients were assigned within 5 days posttransplant to low-exposure everolimus (3–6 ng/mL) with reduced-exposure cyclosporine (n = 56), or standard-exposure cyclosporine (n = 59...... infection was less common with everolimus (5.4% vs. 30.5%, p heart transplantation. Since postoperative safety...

The in vivo toxicity of hydroxyurea depends on its direct target catalase.

Science.gov (United States)

Juul, Trine; Malolepszy, Anna; Dybkaer, Karen; Kidmose, Rune; Rasmussen, Jan Trige; Andersen, Gregers Rom; Johnsen, Hans Erik; Jørgensen, Jan-Elo; Andersen, Stig Uggerhøj

2010-07-09

Hydroxyurea (HU) is a well tolerated ribonucleotide reductase inhibitor effective in HIV, sickle cell disease, and blood cancer therapy. Despite a positive initial response, however, most treated cancers eventually progress due to development of HU resistance. Although RNR properties influence HU resistance in cell lines, the mechanisms underlying cancer HU resistance in vivo remain unclear. To address this issue, we screened for HU resistance in the plant Arabidopsis thaliana and identified seventeen unique catalase mutants, thereby establishing that HU toxicity depends on catalase in vivo. We further demonstrated that catalase is a direct HU target by showing that HU acts as a competitive inhibitor of catalase-mediated hydrogen peroxide decomposition. Considering also that catalase can accelerate HU decomposition in vitro and that co-treatment with another catalase inhibitor alleviates HU effects in vivo, our findings suggests that HU could act as a catalase-activated pro-drug. Clinically, we found high catalase activity in circulating cells from untreated chronic myeloid leukemia, offering a possible explanation for the efficacy of HU against this malignancy.

Molecular Mechanisms of Microcystin Toxicity in Animal Cells

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Alexandre Campos

2010-01-01

Full Text Available Microcystins (MC are potent hepatotoxins produced by the cyanobacteria of the genera Planktothrix, Microcystis, Aphanizomenon, Nostoc and Anabaena. These cyclic heptapeptides have strong affinity to serine/threonine protein phosphatases (PPs thereby acting as an inhibitor of this group of enzymes. Through this interaction a cascade of events responsible for the MC cytotoxic and genotoxic effects in animal cells may take place. Moreover MC induces oxidative stress in animal cells and together with the inhibition of PPs, this pathway is considered to be one of the main mechanisms of MC toxicity. In recent years new insights on the key enzymes involved in the signal-transduction and toxicity have been reported demonstrating the complexity of the interaction of these toxins with animal cells. Key proteins involved in MC up-take, biotransformation and excretion have been identified, demonstrating the ability of aquatic animals to metabolize and excrete the toxin. MC have shown to interact with the mitochondria. The consequences are the dysfunction of the organelle, induction of reactive oxygen species (ROS and cell apoptosis. MC activity leads to the differential expression/activity of transcriptional factors and protein kinases involved in the pathways of cellular differentiation, proliferation and tumor promotion activity. This activity may result from the direct inhibition of the protein phosphatases PP1 and PP2A. This review aims to summarize the increasing data regarding the molecular mechanisms of MC toxicity in animal systems, reporting for direct MC interacting proteins and key enzymes in the process of toxicity biotransformation/excretion of these cyclic peptides.

Monoamine oxidase inhibitors l-deprenyl and clorgyline protect nonmalignant human cells from ionising radiation and chemotherapy toxicity.

LENUS (Irish Health Repository)

Seymour, C B

2003-11-17

l-Deprenyl (R-(-)-deprenyl, selegiline) is an inhibitor of monoamine oxidase-B (MAO-B) that is known to protect nerve cells from a variety of chemical and physical insults. As apoptosis is a common mechanism of radiation-induced cell death, the effect of l-deprenyl on the survival of cultured cells and tissue explants was studied following exposure to gamma radiation. The results obtained were compared with the effects of the less-selective MAO-B inhibitor pargyline and the MAO-A inhibitor clorgyline. l-Deprenyl at a concentration of 10(-9) M protected the nontumorigenic cell line (HaCaT) and normal human urothelial explants from the effects of cobalt-60 gamma radiation, but did not protect tumorigenic human cell lines HaCaT-ras, HPV-transfected human keratinocytes (HPV-G cells), or PC3. Human bladder carcinoma explants were not protected. Clorgyline showed a smaller protective effect of normal cells, whereas pargyline had no effect. Radiation-induced delayed effects (genomic instability measured as delayed cell death) were prevented in normal cells by l-deprenyl but, interestingly, deprenyl appeared to increase the amount of delayed death in the tumorigenic cell lines. Studies using l-deprenyl prior to the exposure of nonmalignant cells to cisplatin showed that cell death due to this agent was also reduced. Treatment of cultures of nontumorigenic cells with l-deprenyl or clorgyline significantly increased the levels of the protein Bcl-2 following irradiation, but there was no such effect on the already-elevated levels of this protein in the tumour samples. Since the Bcl-2 has been shown to be an inhibitor of apoptosis or programmed cell death, this would imply that the protective effects of l-deprenyl and clorgyline involve activation of antiapoptotic pathways within the normal cell. This hypothesis is supported by data showing reduced levels of apoptosis in HaCAT cells and in normal bladder explant cultures following treatment with l-deprenyl.

Discovery of novel, highly potent, and selective quinazoline-2-carboxamide-based matrix metalloproteinase (MMP)-13 inhibitors without a zinc binding group using a structure-based design approach.

Science.gov (United States)

Nara, Hiroshi; Sato, Kenjiro; Naito, Takako; Mototani, Hideyuki; Oki, Hideyuki; Yamamoto, Yoshio; Kuno, Haruhiko; Santou, Takashi; Kanzaki, Naoyuki; Terauchi, Jun; Uchikawa, Osamu; Kori, Masakuni

2014-11-13

Matrix metalloproteinase-13 (MMP-13) has been implicated to play a key role in the pathology of osteoarthritis. On the basis of X-ray crystallography, we designed a series of potent MMP-13 selective inhibitors optimized to occupy the distinct deep S1' pocket including an adjacent branch. Among them, carboxylic acid inhibitor 21k exhibited excellent potency and selectivity for MMP-13 over other MMPs. An effort to convert compound 21k to the mono sodium salt 38 was promising in all animal species studied. Moreover, no overt toxicity was observed in a preliminary repeat dose oral toxicity study of compound 21k in rats. A single oral dose of compound 38 significantly reduced degradation products (CTX-II) released from articular cartilage into the joint cavity in a rat MIA model in vivo. In this article, we report the discovery of highly potent, selective, and orally bioavailable MMP-13 inhibitors as well as their detailed structure-activity data.

Tetrodotoxin: Chemistry, Toxicity, Source, Distribution and Detection

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Vaishali Bane

2014-02-01

Full Text Available Tetrodotoxin (TTX is a naturally occurring toxin that has been responsible for human intoxications and fatalities. Its usual route of toxicity is via the ingestion of contaminated puffer fish which are a culinary delicacy, especially in Japan. TTX was believed to be confined to regions of South East Asia, but recent studies have demonstrated that the toxin has spread to regions in the Pacific and the Mediterranean. There is no known antidote to TTX which is a powerful sodium channel inhibitor. This review aims to collect pertinent information available to date on TTX and its analogues with a special emphasis on the structure, aetiology, distribution, effects and the analytical methods employed for its detection.

The irreversible ERBB1/2/4 inhibitor neratinib interacts with the BCL-2 inhibitor venetoclax to kill mammary cancer cells.

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Booth, Laurence; Roberts, Jane L; Avogadri-Connors, Francesca; Cutler, Richard E; Lalani, Alshad S; Poklepovic, Andrew; Dent, Paul

2018-03-04

The irreversible ERBB1/2/4 inhibitor, neratinib, down-regulates the expression of ERBB1/2/4 as well as the levels of MCL-1 and BCL-XL. Venetoclax (ABT199) is a BCL-2 inhibitor. At physiologic concentrations neratinib interacted in a synergistic fashion with venetoclax to kill HER2 + and TNBC mammary carcinoma cells. This was associated with the drug-combination: reducing the expression and phosphorylation of ERBB1/2/3; in an eIF2α-dependent fashion reducing the expression of MCL-1 and BCL-XL and increasing the expression of Beclin1 and ATG5; and increasing the activity of the ATM-AMPKα-ULK1 S317 pathway which was causal in the formation of toxic autophagosomes. Although knock down of BAX or BAK reduced drug combination lethality, knock down of BAX and BAK did not prevent the drug combination from increasing autophagosome and autolysosome formation. Knock down of ATM, AMPKα, Beclin1 or over-expression of activated mTOR prevented the induction of autophagy and in parallel suppressed tumor cell killing. Knock down of ATM, AMPKα, Beclin1 or cathepsin B prevented the drug-induced activation of BAX and BAK whereas knock down of BID was only partially inhibitory. A 3-day transient exposure of established estrogen-independent HER2 + BT474 mammary tumors to neratinib or venetoclax did not significantly alter tumor growth whereas exposure to [neratinib + venetoclax] caused a significant 7-day suppression of growth by day 19. The drug combination neither altered animal body mass nor behavior. We conclude that venetoclax enhances neratinib lethality by facilitating toxic BH3 domain protein activation via autophagy which enhances the efficacy of neratinib to promote greater levels of cell killing.

Everolimus in Heart Transplantation: An Update

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Stephan W. Hirt

2013-01-01

Full Text Available The evidence base relating to the use of everolimus in heart transplantation has expanded considerably in recent years, providing clinically relevant information regarding its use in clinical practice. Unless there are special considerations to take into account, all de novo heart transplant patients can be regarded as potential candidates for immunosuppression with everolimus and reduced-exposure calcineurin inhibitor therapy. Caution about the use of everolimus immediately after transplantation should be exercised in certain patients with the risk of severe proteinuria, with poor wound healing, or with uncontrolled severe hyperlipidemia. Initiation of everolimus in the early phase aftertransplant is not advisable in patients with severe pretransplant end-organ dysfunction or in patients on a left ventricular assist device beforetransplant who are at high risk of infection or of wound healing complications. The most frequent reason for introducing everolimus in maintenance heart transplant patients is to support minimization or withdrawal of calcineurin inhibitor therapy, for example, due to impaired renal function or malignancy. Due to its potential to inhibit the progression of cardiac allograft vasculopathy and to reduce cytomegalovirus infection, everolimus should be initiated as soon as possible after heart transplantation. Immediate and adequate reduction of CNI exposure is mandatory from the start of everolimus therapy.

Sifuvirtide, a potent HIV fusion inhibitor peptide

International Nuclear Information System (INIS)

Wang, Rui-Rui; Yang, Liu-Meng; Wang, Yun-Hua; Pang, Wei; Tam, Siu-Cheung; Tien, Po; Zheng, Yong-Tang

2009-01-01

Enfuvirtide (ENF) is currently the only FDA approved HIV fusion inhibitor in clinical use. Searching for more drugs in this category with higher efficacy and lower toxicity seems to be a logical next step. In line with this objective, a synthetic peptide with 36 amino acid residues, called Sifuvirtide (SFT), was designed based on the crystal structure of gp41. In this study, we show that SFT is a potent anti-HIV agent with relatively low cytotoxicity. SFT was found to inhibit replication of all tested HIV strains. The effective concentrations that inhibited 50% viral replication (EC 50 ), as determined in all tested strains, were either comparable or lower than benchmark values derived from well-known anti-HIV drugs like ENF or AZT, while the cytotoxic concentrations causing 50% cell death (CC 50 ) were relatively high, rendering it an ideal anti-HIV agent. A GST-pull down assay was performed to confirm that SFT is a fusion inhibitor. Furthermore, the activity of SFT on other targets in the HIV life cycle was also investigated, and all assays showed negative results. To further understand the mechanism of action of HIV peptide inhibitors, resistant variants of HIV-1 IIIB were derived by serial virus passage in the presence of increasing doses of SFT or ENF. The results showed that there was cross-resistance between SFT and ENF. In conclusion, SFT is an ideal anti-HIV agent with high potency and low cytotoxicity, but may exhibit a certain extent of cross-resistance with ENF.

Does the nature of residual immune function explain the differential risk of non-melanoma skin cancer development in immunosuppressed organ transplant recipients?

DEFF Research Database (Denmark)

Jung, Ji-Won; Overgaard, Nana H; Burke, Michael T

2016-01-01

; in particular, patients switched from calcineurin inhibitors to mammalian target of rapamycin (mTOR) inhibitors not only displayed a dramatic reduction in new tumor formation but also in some cases a regression of their existing lesions. Studies of cancer models in mice and cell lines in the laboratory have...... attributed these discrepancies in cancer risk to the ability of immunosuppressants such as mTOR inhibitors to elicit direct anticancer effects, including suppressing angiogenesis and increasing autophagy-mediated DNA repair. Recent evidence from the immunological literature however, suggests a significant...... alternative contribution of mTOR inhibitors; namely the promotion of memory T-cell function. Recent advances in understanding memory T-cell establishment and the demonstration of their critical role in long-term immunity make it timely to review the available evidence as to whether the improved nonmelanoma...

Identification of selective inhibitors of RET and comparison with current clinical candidates through development and validation of a robust screening cascade [version 1; referees: 2 approved

Directory of Open Access Journals (Sweden)

Amanda J. Watson

2016-05-01

Full Text Available RET (REarranged during Transfection is a receptor tyrosine kinase, which plays pivotal roles in regulating cell survival, differentiation, proliferation, migration and chemotaxis. Activation of RET is a mechanism of oncogenesis in medullary thyroid carcinomas where both germline and sporadic activating somatic mutations are prevalent.   At present, there are no known specific RET inhibitors in clinical development, although many potent inhibitors of RET have been opportunistically identified through selectivity profiling of compounds initially designed to target other tyrosine kinases. Vandetanib and cabozantinib, both multi-kinase inhibitors with RET activity, are approved for use in medullary thyroid carcinoma, but additional pharmacological activities, most notably inhibition of vascular endothelial growth factor - VEGFR2 (KDR, lead to dose-limiting toxicity. The recent identification of RET fusions present in ~1% of lung adenocarcinoma patients has renewed interest in the identification and development of more selective RET inhibitors lacking the toxicities associated with the current treatments.   In an earlier publication [Newton et al, 2016; 1] we reported the discovery of a series of 2-substituted phenol quinazolines as potent and selective RET kinase inhibitors. Here we describe the development of the robust screening cascade which allowed the identification and advancement of this chemical series.  Furthermore we have profiled a panel of RET-active clinical compounds both to validate the cascade and to confirm that none display a RET-selective target profile.

Structure-Based Drug Design of Small Molecule Peptide Deformylase Inhibitors to Treat Cancer

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Jian Gao

2016-03-01

Full Text Available Human peptide deformylase (HsPDF is an important target for anticancer drug discovery. In view of the limited HsPDF, inhibitors were reported, and high-throughput virtual screening (HTVS studies based on HsPDF for developing new PDF inhibitors remain to be reported. We reported here on diverse small molecule inhibitors with excellent anticancer activities designed based on HTVS and molecular docking studies using the crystal structure of HsPDF. The compound M7594_0037 exhibited potent anticancer activities against HeLa, A549 and MCF-7 cell lines with IC50s of 35.26, 29.63 and 24.63 μM, respectively. Molecular docking studies suggested that M7594_0037 and its three derivatives could interact with HsPDF by several conserved hydrogen bonds. Moreover, the pharmacokinetic and toxicity properties of M7594_0037 and its derivatives were predicted using the OSIRIS property explorer. Thus, M7594_0037 and its derivatives might represent a promising scaffold for the further development of novel anticancer drugs.

Clostridium species strain BOH3 tolerates and transforms inhibitors from horticulture waste hydrolysates.

Science.gov (United States)

Yan, Yu; He, Jianzhong

2017-08-01

Conversion of lignocellulosic hydrolysate to biofuels is impeded by the toxic effects of inhibitors that are generated during pretreatment and hydrolysis processes. Here we describe a wild-type Clostridium sp. strain BOH3 with high tolerance to the lignocellulose-derived inhibitors and its capability to transform these inhibitors. Strain BOH3 is capable of tolerating over 60 mM furfural, 60 mM hydroxymethylfurfural, and 6.6 mM vanillin, respectively, and is able to convert 53.74 ± 0.37 mM furfural into furfuryl alcohol within 90 h. The high furfural tolerance and its biotransformation by strain BOH3, which is correlated to the high transcription levels of two short-chain dehydrogenase/reductases, enable strain BOH3 to produce 5.15 ± 0.52 g/L butanol from dilute sulfuric acid pretreated horticultural waste hydrolysate (HWH) that bypassed the detoxification step. The capability of strain BOH3 to produce butanol from un-detoxified HWH lays the foundation of cost-effective biofuel production from lignocellulosic materials.

Restoring conjunctival tolerance by topical nuclear factor-κB inhibitors reduces preservative-facilitated allergic conjunctivitis in mice.

Science.gov (United States)

Guzmán, Mauricio; Sabbione, Florencia; Gabelloni, María Laura; Vanzulli, Silvia; Trevani, Analía Silvina; Giordano, Mirta Nilda; Galletti, Jeremías Gastón

2014-09-04

To evaluate the role of nuclear factor-κB (NF-κB) activation in eye drop preservative toxicity and the effect of topical NF-κB inhibitors on preservative-facilitated allergic conjunctivitis. Balb/c mice were instilled ovalbumin (OVA) combined with benzalkonium chloride (BAK) and/or NF-κB inhibitors in both eyes. After immunization, T-cell responses and antigen-induced ocular inflammation were evaluated. Nuclear factor-κB activation and associated inflammatory changes also were assessed in murine eyes and in an epithelial cell line after BAK exposure. Benzalkonium chloride promoted allergic inflammation and leukocyte infiltration of the conjunctiva. Topical NF-κB inhibitors blocked the disruptive effect of BAK on conjunctival immunological tolerance and ameliorated subsequent ocular allergic reactions. In line with these findings, BAK induced NF-κB activation and the secretion of IL-6 and granulocyte-monocyte colony-stimulating factor in an epithelial cell line and in the conjunctiva of instilled mice. In addition, BAK favored major histocompatibility complex (MHC) II expression in cultured epithelial cells in an NF-κB-dependent fashion after interaction with T cells. Benzalkonium chloride triggers conjunctival epithelial NF-κB activation, which seems to mediate some of its immune side effects, such as proinflammatory cytokine release and increased MHC II expression. Breakdown of conjunctival tolerance by BAK favors allergic inflammation, and this effect can be prevented in mice by topical NF-κB inhibitors. These results suggest a new pharmacological target for preservative toxicity and highlight the importance of conjunctival tolerance in ocular surface homeostasis. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

β-Amyloid-derived pentapeptide RIIGLa inhibits Aβ1-42 aggregation and toxicity

International Nuclear Information System (INIS)

Fueloep, Livia; Zarandi, Marta; Datki, Zsolt; Soos, Katalin; Penke, Botond

2004-01-01

Pr-IIGL a , a derivative of the tetrapeptide β-amyloid 31-34 (Aβ 31-34 ), exerts controversial effects: it is toxic in a neuroblastoma culture, but it protects glial cells from the cytotoxic action of Aβ 1-42 . For an understanding of this phenomenon, a new pentapeptide, RIIGL a was synthetized, and both compounds were studied by different physicochemical and biological methods. Transmission electron microscopic (TEM) studies revealed that Pr-IIGL a forms fibrillar aggregates, whereas RIIGL a does not form fibrils. Congo red binding studies furnished the same results. Aggregated Pr-IIGL a acts as a cytotoxic agent in neuroblastoma cultures, but RIIGL a does not display inherent toxicity. RIIGL a co-incubated with Aβ 1-42 inhibits the formation of mature amyloid fibres (TEM studies) and reduces the cytotoxic effect of fibrillar Aβ 1-42 . These results indicate that RIIGL a is an effective inhibitor of both the aggregation and the toxic effects of Aβ 1-42 and can serve as a lead compound for the design of novel neuroprotective peptidomimetics

Etude rétrospective de l'influence des polymorphismes génétiques de CYP3A4, CYP3A5 et ABCB1 des donneurs et des receveurs sur les effets des immunosuppresseurs en transplantation hépatique

OpenAIRE

Gratien-Debette , Marilyne

2015-01-01

Liver transplantation is now a well mastered surgery with standardized procedures, but the long-term clinical outcomes of the graft and the patient remain uncertain. The pharmacogenetic study of the calcineurin inhibitors (CNI) cyclosporine and tacrolimus should help to understand the variability of their pharmacokinetics and therapeutic or side effects. In the first part of this work, we reviewed the main pharmacogenetic studies of CNI in liver transplantation, focusing on the three polymorp...

Inhibitors

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... JM, and the Hemophilia Inhibitor Research Study Investigators. Validation of Nijmegen-Bethesda assay modifications to allow inhibitor ... webinars on blood disorders Language: English (US) Español (Spanish) File Formats Help: How do I view different ...

Crystallization and preliminary crystallographic analysis of the human calcineurin homologous protein CHP2 bound to the cytoplasmic region of the Na{sup +}/H{sup +} exchanger NHE1

Energy Technology Data Exchange (ETDEWEB)

Ben Ammar, Youssef [Department of Molecular Physiology, National Cardiovascular Center Research Institute, Fujishiro-dai 5-7-1, Suita, Osaka 565-8565 (Japan); Takeda, Soichi [Department of Cardiac Physiology, National Cardiovascular Center Research Institute, Fujishiro-dai 5-7-1, Suita, Osaka 565-8565 (Japan); Sugawara, Mitsuaki; Miyano, Masashi [Structural Biophysics Laboratory, RIKEN Harima Institute at SPring-8, Kouto, Mikazuki, Sayo, Hyogo 679-5148 (Japan); Mori, Hidezo [Department of Cardiac Physiology, National Cardiovascular Center Research Institute, Fujishiro-dai 5-7-1, Suita, Osaka 565-8565 (Japan); Wakabayashi, Shigeo, E-mail: wak@ri.ncvc.go.jp [Department of Molecular Physiology, National Cardiovascular Center Research Institute, Fujishiro-dai 5-7-1, Suita, Osaka 565-8565 (Japan)

2005-10-01

Crystallization of the human CHP2–NHE1 binding domain complex. Calcineurin homologous protein (CHP) is a Ca{sup 2+}-binding protein that directly interacts with and regulates the activity of all plasma-membrane Na{sup +}/H{sup +}-exchanger (NHE) family members. In contrast to the ubiquitous isoform CHP1, CHP2 is highly expressed in cancer cells. To understand the regulatory mechanism of NHE1 by CHP2, the complex CHP2–NHE1 (amino acids 503–545) has been crystallized by the sitting-drop vapour-diffusion method using PEG 3350 as precipitant. The crystals diffract to 2.7 Å and belong to a tetragonal space group, with unit-cell parameters a = b = 49.96, c = 103.20 Å.

Snake Venom PLA2s Inhibitors Isolated from Brazilian Plants: Synthetic and Natural Molecules

Science.gov (United States)

Carvalho, B. M. A.; Santos, J. D. L.; Xavier, B. M.; Almeida, J. R.; Resende, L. M.; Martins, W.; Marcussi, S.; Marangoni, S.; Stábeli, R. G.; Calderon, L. A.; Soares, A. M.; Da Silva, S. L.; Marchi-Salvador, D. P.

2013-01-01

Ophidian envenomation is an important health problem in Brazil and other South American countries. In folk medicine, especially in developing countries, several vegetal species are employed for the treatment of snakebites in communities that lack prompt access to serum therapy. However, the identification and characterization of the effects of several new plants or their isolated compounds, which are able to inhibit the activities of snake venom, are extremely important and such studies are imperative. Snake venom contains several organic and inorganic compounds; phospholipases A2 (PLA2s) are one of the principal toxic components of venom. PLA2s display a wide variety of pharmacological activities, such as neurotoxicity, myotoxicity, cardiotoxicity, anticoagulant, hemorrhagic, and edema-inducing effects. PLA2 inhibition is of pharmacological and therapeutic interests as these enzymes are involved in several inflammatory diseases. This review describes the results of several studies of plant extracts and their isolated active principles, when used against crude snake venoms or their toxic fractions. Isolated inhibitors, such as steroids, terpenoids, and phenolic compounds, are able to inhibit PLA2s from different snake venoms. The design of specific inhibitors of PLA2s might help in the development of new pharmaceutical drugs, more specific antivenom, or even as alternative approaches for treating snakebites. PMID:24171158

Snake Venom PLA2s Inhibitors Isolated from Brazilian Plants: Synthetic and Natural Molecules

Directory of Open Access Journals (Sweden)

B. M. A. Carvalho

2013-01-01

Full Text Available Ophidian envenomation is an important health problem in Brazil and other South American countries. In folk medicine, especially in developing countries, several vegetal species are employed for the treatment of snakebites in communities that lack prompt access to serum therapy. However, the identification and characterization of the effects of several new plants or their isolated compounds, which are able to inhibit the activities of snake venom, are extremely important and such studies are imperative. Snake venom contains several organic and inorganic compounds; phospholipases A2 (PLA2s are one of the principal toxic components of venom. PLA2s display a wide variety of pharmacological activities, such as neurotoxicity, myotoxicity, cardiotoxicity, anticoagulant, hemorrhagic, and edema-inducing effects. PLA2 inhibition is of pharmacological and therapeutic interests as these enzymes are involved in several inflammatory diseases. This review describes the results of several studies of plant extracts and their isolated active principles, when used against crude snake venoms or their toxic fractions. Isolated inhibitors, such as steroids, terpenoids, and phenolic compounds, are able to inhibit PLA2s from different snake venoms. The design of specific inhibitors of PLA2s might help in the development of new pharmaceutical drugs, more specific antivenom, or even as alternative approaches for treating snakebites.

Intracellular haemolytic agents of Heterocapsa circularisquama exhibit toxic effects on H. circularisquama cells themselves and suppress both cell-mediated haemolytic activity and toxicity to rotifers (Brachionus plicatilis).

Science.gov (United States)

Nishiguchi, Tomoki; Cho, Kichul; Yasutomi, Masumi; Ueno, Mikinori; Yamaguchi, Kenichi; Basti, Leila; Yamasaki, Yasuhiro; Takeshita, Satoshi; Kim, Daekyung; Oda, Tatsuya

2016-10-01

A harmful dinoflagellate, Heterocapsa circularisquama, is highly toxic to shellfish and the zooplankton rotifer Brachionus plicatilis. A previous study found that H. circularisquama has both light-dependent and -independent haemolytic agents, which might be responsible for its toxicity. Detailed analysis of the haemolytic activity of H. circularisquama suggested that light-independent haemolytic activity was mediated mainly through intact cells, whereas light-dependent haemolytic activity was mediated by intracellular agents which can be discharged from ruptured cells. Because H. circularisquama showed similar toxicity to rotifers regardless of the light conditions, and because ultrasonic ruptured H. circularisquama cells showed no significant toxicity to rotifers, it was suggested that live cell-mediated light-independent haemolytic activity is a major factor responsible for the observed toxicity to rotifers. Interestingly, the ultrasonic-ruptured cells of H. circularisquama suppressed their own lethal effect on the rotifers. Analysis of samples of the cell contents (supernatant) and cell fragments (precipitate) prepared from the ruptured H. circularisquama cells indicated that the cell contents contain inhibitors for the light-independent cell-mediated haemolytic activity, toxins affecting H. circularisquama cells themselves, as well as light-dependent haemolytic agents. Ethanol extract prepared from H. circularisquama, which is supposed to contain a porphyrin derivative that displays photosensitising haemolytic activity, showed potent toxicity to Chattonella marina, Chattonella antiqua, and Karenia mikimotoi, as well as to H. circularisquama at the concentration range at which no significant toxicity to rotifers was observed. Analysis on a column of Sephadex LH-20 revealed that light-dependent haemolytic activity and inhibitory activity on cell-mediated light-independent haemolytic activity existed in two separate fractions (f-2 and f-3), suggesting that both

Herbicide toxicity on river biofilms assessed by pulse amplitude modulated (PAM) fluorometry

International Nuclear Information System (INIS)

Kim Tiam, Sandra; Laviale, Martin; Feurtet-Mazel, Agnès; Jan, Gwilherm; Gonzalez, Patrice; Mazzella, Nicolas; Morin, Soizic

2015-01-01

Highlights: • Rapid Light Curves were shown to be early markers of toxicant exposure. • Diuron and norflurazon effects were significant at environmentally realistic concentrations. • Toxic effects in intact biofilms seem to be delayed compared to disrupted biofilms. - Abstract: The use of Rapid light curves (RLCs) as a toxicity endpoint for river biofilms was examined in this study and compared to “classical fluorescence parameters” i.e. minimal fluorescence (F 0 ), optimal and effective quantum yields of photosystem II (F v /F m and Φ PSII ). Measurements were performed after exposure to five concentrations of diuron (from 0.3 to 33.4 μg L −1 ), its main degradation product (DCPMU) (from 1.0 to 1014 μg L −1 ) and norflurazon (from 0.6 to 585 μg L −1 ) with the lowest exposure concentrations corresponding to levels regularly encountered in chronically contaminated sites. Biofilm responses were evaluated after 1, 5, 7 and 14 days of exposure to the different toxicants. Overall, the responses of both “classical fluorescence parameters” and RLC endpoints were highly time dependent and related to the mode of action of the different compounds. Interestingly, parameters calculated from RLCs (α, ETR max and I k ) were useful early markers of pesticide exposure since they revealed significant effects of all the tested toxicants from the first day of exposure. In comparison, classical fluorescence endpoints (F 0 and F v /F m ) measured at day 1 were only affected in the DCPMU treatment. Our results demonstrated the interest of RLCs as early markers of toxicant exposure particularly when working with toxicants with less specific mode of action than PSII inhibitors

Corticosteroid therapy in the treatment of pediatric patients with atopic dermatitis

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Leopold, Christine

2007-09-01

Full Text Available Health political background: In developed countries 2.5% of the population - mainly children - are affected by atopic dermatitis. During the past few years its prevalence amongst school children has risen decisively and now lies between 8% to 16%. It is the most frequent chronic skin disease amongst school-aged children. Scientific background: Current methods of treating atopic dermatitis among children focus on containing and preventing the illness’s further progression. Preventing dry skin, relieving symptoms (such as pruritis and inflammation of the skin and identifying and avoiding provocating factors are elementary goals of treatment. Successful treatment can substantially increase the children’s quality of life. Possible therapies of children affected by atopic dermatitis include both topically and systemically applied pharmaceuticals. During the past ten years the use of corticosteroids has been the standard topical anti-inflammatory therapy in case of aggravating inflammations. In 2002 a new group of pharmaceutical substances (topical calcineurin inhibitors tacrolimus and pimecrolimus was authorised in Germany for topical anti-inflammatory treatment of patients. Because of its high prevalence atopic dermatitis represents a major expense factor to the German health care system. In 1999 the costs of the treatment of atopic dermatitis with corticosteroids in Germany amounted to 230 million Euro. If other direct costs for the treatment are included, for example hospitalisation or doctor appointments, the total costs amount to 3.57 billion Euro. Research question: How effective and efficient are topical anti-inflammatory treatments of children with atopic dermatitis? Methods: A systematic literature search was performed in 35 international databases which yielded 1335 articles. Following a two-part selection process according to predefined criteria 24 publications were included in the assessment. Results: Of 19 randomised controlled

Therapeutic applications of histone deacetylase inhibitors in sarcoma.

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Tang, Fan; Choy, Edwin; Tu, Chongqi; Hornicek, Francis; Duan, Zhenfeng

2017-09-01

Sarcomas are a rare group of malignant tumors originating from mesenchymal stem cells. Surgery, radiation and chemotherapy are currently the only standard treatments for sarcoma. However, their response rates to chemotherapy are quite low. Toxic side effects and multi-drug chemoresistance make treatment even more challenging. Therefore, better drugs to treat sarcomas are needed. Histone deacetylase inhibitors (HDAC inhibitors, HDACi, HDIs) are epigenetic modifying agents that can inhibit sarcoma growth in vitro and in vivo through a variety of pathways, including inducing tumor cell apoptosis, causing cell cycle arrest, impairing tumor invasion and preventing metastasis. Importantly, preclinical studies have revealed that HDIs can not only sensitize sarcomas to chemotherapy and radiotherapy, but also increase treatment responses when combined with other chemotherapeutic drugs. Several phase I and II clinical trials have been conducted to assess the efficacy of HDIs either as monotherapy or in combination with standard chemotherapeutic agents or targeted therapeutic drugs for sarcomas. Combination regimen for sarcomas appear to be more promising than monotherapy when using HDIs. This review summarizes our current understanding and therapeutic applications of HDIs in sarcomas. Copyright © 2017 Elsevier Ltd. All rights reserved.

Aquaglyceroporin-null trypanosomes display glycerol transport defects and respiratory-inhibitor sensitivity.

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Laura Jeacock

2017-03-01

Full Text Available Aquaglyceroporins (AQPs transport water and glycerol and play important roles in drug-uptake in pathogenic trypanosomatids. For example, AQP2 in the human-infectious African trypanosome, Trypanosoma brucei gambiense, is responsible for melarsoprol and pentamidine-uptake, and melarsoprol treatment-failure has been found to be due to AQP2-defects in these parasites. To further probe the roles of these transporters, we assembled a T. b. brucei strain lacking all three AQP-genes. Triple-null aqp1-2-3 T. b. brucei displayed only a very moderate growth defect in vitro, established infections in mice and recovered effectively from hypotonic-shock. The aqp1-2-3 trypanosomes did, however, display glycerol uptake and efflux defects. They failed to accumulate glycerol or to utilise glycerol as a carbon-source and displayed increased sensitivity to salicylhydroxamic acid (SHAM, octyl gallate or propyl gallate; these inhibitors of trypanosome alternative oxidase (TAO can increase intracellular glycerol to toxic levels. Notably, disruption of AQP2 alone generated cells with glycerol transport defects. Consistent with these findings, AQP2-defective, melarsoprol-resistant clinical isolates were sensitive to the TAO inhibitors, SHAM, propyl gallate and ascofuranone, relative to melarsoprol-sensitive reference strains. We conclude that African trypanosome AQPs are dispensable for viability and osmoregulation but they make important contributions to drug-uptake, glycerol-transport and respiratory-inhibitor sensitivity. We also discuss how the AQP-dependent inverse sensitivity to melarsoprol and respiratory inhibitors described here might be exploited.

Efficacy and gastrointestinal tolerability of ML3403, a selective inhibitor of p38 MAP kinase and CBS-3595, a dual inhibitor of p38 MAP kinase and phosphodiesterase 4 in CFA-induced arthritis in rats.

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Koch, Diana A; Silva, Rodrigo B M; de Souza, Alessandra H; Leite, Carlos E; Nicoletti, Natália F; Campos, Maria M; Laufer, Stefan; Morrone, Fernanda B

2014-03-01

Mitogen-activated protein kinase (MAPK) p38 inhibitors have entered the clinical phase, although many of them have failed due to high toxicity and lack of efficacy. In the present study we compared the effects of the selective p38 inhibitor ML3403 and the dual p38-PDE4 inhibitor CBS-3595, on inflammatory and nociceptive parameters in a model of polyarthritis in rats. Male Wistar rats (180-200 g) were used for the complete Freund's adjuvant (CFA)-induced arthritis model and they were evaluated at 14-21 days. We also analysed the effects of these pharmacological tools on liver and gastrointestinal toxicity and on cytokine levels. Repeated CBS-3595 (3 mg/kg) or ML3403 (10 mg/kg) administration produced significant anti-inflammatory actions in the chronic arthritis model induced by CFA. CBS-3595 and ML3403 treatment also markedly reduced the production of the proinflammatory cytokine IL-6 in the paw tissue, whereas it widely increased the levels of the anti-inflammatory cytokine IL-10. Moreover, CBS-3595 produced partial anti-allodynic effects in the CFA model at 4 and 8 days after treatment. Notably, ML3403 and CBS-3595 did not show marked signs of hepatoxicity, as supported by unaltered histological observations in the liver sections. Finally, both compounds were safe in the gastrointestinal tract, according to evaluation of intestinal biopsies. CBS-3595 displayed a superior profile regarding its anti-inflammatory effects. Thus p38 MAPK/PDE4 blocking might well constitute a relevant strategy for the treatment of RA.

Hypersalinity Acclimation Increases the Toxicity of the Insecticide Phorate in Coho Salmon (Oncorhynchus kisutch)

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Lavado, Ramon; Maryoung, Lindley A.; Schlenk, Daniel

2012-01-01

Previous studies in euryhaline fish have shown that acclimation to hypersaline environments enhances the toxicity of thioether organophosphate and carbamate pesticides. To better understand the potential mechanism of enhanced toxicity, the effects of the organophosphate insecticide phorate were evaluated in coho salmon (Oncorhynchus kisutch) maintained in freshwater (salinity-dependent manner. In contrast, formation of phorate-oxon (gill; olfactory tissues), phorate sulfone (liver), and phorate-oxon sulfoxide (liver; olfactory tissues) was significantly enhanced in fish acclimated to higher salinities. From previous studies, it was expected that phorate and phorate sulfoxide would be less potent AChE inhibitors than phorate-oxon, with phorate-oxon sulfoxide being the most potent of the compounds tested. This trend was confirmed in this study. In summary, these results suggest that differential expression and/or catalytic activities of Phase I enzymes may be involved to enhance phorate oxidative metabolism and subsequent toxicity of phorate to coho salmon under hypersaline conditions. The outcome may be enhanced fish susceptibility to anticholineterase oxon sulfoxides. PMID:21488666

Cyclosporin A preferentially attenuates skeletal slow-twitch muscle regeneration

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Miyabara E.H.

2005-01-01

Full Text Available Calcineurin, a Ca2+/calmodulin-dependent phosphatase, is associated with muscle regeneration via NFATc1/GATA2-dependent pathways. However, it is not clear whether calcineurin preferentially affects the regeneration of slow- or fast-twitch muscles. We investigated the effect of a calcineurin inhibitor, cyclosporin A (CsA, on the morphology and fiber diameter of regenerating slow- and fast-twitch muscles. Adult Wistar rats (259.5 ± 9 g maintained under standard conditions were treated with CsA (20 mg/kg body weight, ip for 5 days, submitted to cryolesion of soleus and tibialis anterior (TA muscles on the 6th day, and then treated with CsA for an additional 21 days. The muscles were removed, weighed, frozen, and stored in liquid nitrogen. Cryolesion did not alter the body weight gain of the animals after 21 days of regeneration (P = 0.001 and CsA significantly reduced the body weight gain (15.5%; P = 0.01 during the same period. All treated TA and soleus muscles showed decreased weights (17 and 29%, respectively, P < 0.05. CsA treatment decreased the cross-sectional area of both soleus and TA muscles of cryoinjured animals (TA: 2108 ± 930 vs 792 ± 640 µm²; soleus: 2209 ± 322 vs 764 ± 439 m²; P < 0.001. Histological sections of both muscles stained with Toluidine blue revealed similar regenerative responses after cryolesion. In addition, CsA was able to minimize these responses, i.e., centralized nuclei and split fibers, more efficiently so in TA muscle. These results indicate that calcineurin preferentially plays a role in regeneration of slow-twitch muscle.

Intraesophageal administratio (JP4-039) and p53/MDM2/MDM4 Inhibitor (BEB55) ameliorates radiation esophagitisn of GS-Nitroxide

NARCIS (Netherlands)

Kim, H.; Bernard, M.; Epperly, M.W.; Shen, H.; Dixon, T.M.; Amoscato, A.A.; Doemling, A.S.; Li, S.; Gao, X.; Wipf, P.

2011-01-01

Purpose/Objective(s): To evaluate the esophageal radiation dose modification properties of the GS-nitroxide (JP4-039) and the p53/MDM2/MDM4 inhibitor (BEB55). Materials/Methods: Esophagitis is a significant toxicity of radiation therapy of thoracic cancers. We evaluated radiation dose modification

A calcineurin inhibitory protein overexpressed in Down's syndrome interacts with the product of a ubiquitously expressed transcript

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H.C.S. Silveira

2004-06-01

Full Text Available The Down's syndrome candidate region 1 (DSCR1 protein, encoded by a gene located in the human chromosome 21, interacts with calcineurin and is overexpressed in Down's syndrome patients. As an approach to clarifying a putative function for this protein, in the present study we used the yeast two-hybrid system to identify DSCR1 partners. The two-hybrid system is a method that allows the identification of protein-protein interactions through reconstitution of the activity of the yeast GAL 4 transcriptional activator. The gene DSCR1 fused to the GAL 4 binding domain (BD was used to screen a human fetal brain cDNA library cloned in fusion with the GAL 4 activation domain (AD. Three positive clones were found and sequence analysis revealed that all the plasmids coded for the ubiquitously expressed transcript (UXT. UXT, which is encoded in human Xp11, is a 157-amino acid protein present in both cytosol and nucleus of the cells. This positive interaction of DSCR1 and UXT was confirmed in vivo by mating the yeast strain AH109 (MATaexpressing AD-UXT with the strain Y187 (MATalpha expressing BD-DSCR1, and in vitro by co-immunoprecipitation experiments. These results may help elucidate a new function for DSCR1 and its participation in Down's syndrome pathogenesis.

Monitoring and Management of Toxicities of Novel B Cell Signaling Agents.

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Rhodes, Joanna; Mato, Anthony; Sharman, Jeff P

2018-04-11

B cell signaling agents, including ibrutinib, idelalisib, and the BCL-2 inhibitor venetoclax have become an integral part of therapy for patients with non-Hodgkin's lymphomas. The toxicity profiles of these medications is distinct from chemoimmunotherapy. Here, we will review the mechanism of action of these drugs, their efficacy, and toxicity management. Ibrutinib use is associated with increased risk of atrial fibrillation and bleeding which can be managed using dose interruptions and modifications. Patients on idelalisib require close clinical and frequent laboratory monitoring, particularly of liver function tests to ensure there are no serious adverse events. Monitoring for infections is important in patients on both idelalisib and ibrutinib. Venetoclax requires close clinical and laboratory monitoring to prevent significant tumor lysis. Targeted B cell receptor therapies each have unique side effect profiles which require careful clinical monitoring. As we continue to use these therapies, optimal management strategies will continue to be elucidated.

Pharmacogenetics predictive of response and toxicity in acute lymphoblastic leukemia therapy.

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Mei, Lin; Ontiveros, Evelena P; Griffiths, Elizabeth A; Thompson, James E; Wang, Eunice S; Wetzler, Meir

2015-07-01

Acute lymphoblastic leukemia (ALL) is a relatively rare disease in adults accounting for no more than 20% of all cases of acute leukemia. By contrast with the pediatric population, in whom significant improvements in long term survival and even cure have been achieved over the last 30years, adult ALL remains a significant challenge. Overall survival in this group remains a relatively poor 20-40%. Modern research has focused on improved pharmacokinetics, novel pharmacogenetics and personalized principles to optimize the efficacy of the treatment while reducing toxicity. Here we review the pharmacogenetics of medications used in the management of patients with ALL, including l-asparaginase, glucocorticoids, 6-mercaptopurine, methotrexate, vincristine and tyrosine kinase inhibitors. Incorporating recent pharmacogenetic data, mainly from pediatric ALL, will provide novel perspective of predicting response and toxicity in both pediatric and adult ALL therapies. Copyright © 2015 Elsevier Ltd. All rights reserved.

Dithiazole thione derivative as competitive NorA efflux pump inhibitor to curtail multi drug resistant clinical isolate of MRSA in a zebrafish infection model.

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Lowrence, Rene Christena; Raman, Thiagarajan; Makala, Himesh V; Ulaganathan, Venkatasubramanian; Subramaniapillai, Selva Ganesan; Kuppuswamy, Ashok Ayyappa; Mani, Anisha; Chittoor Neelakantan, Sundaresan; Nagarajan, Saisubramanian

2016-11-01

Multi drug resistant (MDR) pathogens pose a serious threat to public health since they can easily render most potent drugs ineffective. Efflux pump inhibitors (EPI) can be used to counter the MDR phenotypes arising due to increased efflux. In the present study, a series of dithiazole thione derivatives were synthesized and checked for its antibacterial and efflux pump inhibitory (EPI) activity. Among 10 dithiazole thione derivatives, real-time efflux studies revealed that seven compounds were potent EPIs relative to CCCP. Zebrafish toxicity studies identified four non-toxic putative EPIs. Both DTT3 and DTT9 perturbed membrane potential and DTT6 was haemolytic. Among DTT6 and DTT10, the latter was less toxic as evidenced by histopathology studies. Since DTT10 was non-haemolytic, did not affect the membrane potential, and was least toxic, it was chosen further for in vivo study, wherein DTT10 potentiated effect of ciprofloxacin against clinical strain of MRSA and reduced bacterial burden in muscle and skin tissue of infected zebrafish by ~ 1.7 and 2.5 log fold respectively. Gene expression profiling of major efflux transport proteins by qPCR revealed that clinical isolate of MRSA, in the absence of antibiotic, upregulated NorA, NorB and MepA pump, whereas it downregulates NorC and MgrA relative to wild-type strain of Staphylococcus aureus. In vitro studies with NorA mutant strains and substrate profiling revealed that at higher concentrations DTT10 is likely to function as a competitive inhibitor of NorA efflux protein in S. aureus, whereas at lower concentrations it might inhibit ciprofloxacin efflux through NorB and MepA as implied by docking studies. A novel non-toxic, non-haemolytic dithiazole thione derivative (DTT10) was identified as a potent competitive inhibitor of NorA efflux pump in S. aureus using in silico, in vitro and in vivo studies. This study also underscores the importance of using zebrafish infection model to screen and evaluate putative EPI for

Insulin Increases Expression of TRPC6 Channels in Podocytes by a Calcineurin-Dependent Pathway

DEFF Research Database (Denmark)

Xia, Shengqiang; Liu, Ying; Li, Xinming

2016-01-01

and protein in podocytes. Insulin increased TRPC6 transcripts in a time and dose-dependent manner. The insulin-induced elevation of TRPC6 transcripts was blocked in the presence of tacrolimus, cyclosporine A, and NFAT-inhibitor (each p ANOVA and Bonferroni's multiple comparison test). Transcripts......, cyclosporine A, and NFAT-inhibitor blocked that insulin effect (p ANOVA). Immunofluorescence showed that insulin increased TRPC6-expression on the cell surface. Fluorescence-spectrophotometry and manganese quench experiments indicated that the increased TRPC6-expression after insulin...

Pyrimidine nucleoside analogues, potential chemotherapeutic agents, and substrates/inhibitors in various enzyme systems

International Nuclear Information System (INIS)

Kulikowski, T.; Bretner, M.; Felczak, K.; Drabikowska, A.; Shugar, D.

1998-01-01

substrates for thymidine phosphorylase and were quite inactive vs uridine phosphorylase. S 2 ,3'-F ddUrd proved to be a moderate, and S 2 ,3'-FddThd a potent and selective, inhibitor of the replication of HIV-1 in CEM4 cells, comparable to the activity of the known antiretroviral agent AZT. 5-fluorouridine and 5-fluorocitidine are potent antitumor agent s, but too toxic to be used as drugs. To decrease this toxicity, a new class of branched-chain sugar nucleosides, pyrimidine and purine hamamelose nucleosides, was synthetized, with uracil and 5-fluorouracil derivatives being the most potent antileukemic agents, activities being comparable to that of 5-fluorouridine. (author)

ANGIOGENESIS INHIBITORS FOR THE TREATMENT OF HEPATOCELLULAR CARCINOMA

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Massimiliano Berretta

2016-11-01

Full Text Available Background: Angiogenesis inhibitors have become an important therapeutic approach in the treatment of hepatocellular carcinoma (HCC patients. The achievement of Sorafenib in prolonging overall survival of patients with HCC makes therapeutic inhibition of angiogenesis a fundamental element of the treatment of HCC. Considering the heterogeneous aspects of HCC and to enhance therapeutic efficacy, overcome drug resistance and reduce toxicity, the combination of antiangiogenic drugs with antiblastic chemotherapy (AC, radiotherapy or other targeted drugs have been evaluated. The issue is further complicated by the combination of antiangiogenesis with other AC or biologic drugs. To date, there is no planned approach to determine which patients are more responsive to a given type of antiangiogenic treatment. Conclusion: Large investments in the clinical research are essential to improve treatment response and minimize toxicities for patients with HCC. Future investigations will need to focus on utilizing patterns of genetic information to classify HCC into groups that display similar prognosis and treatment sensitivity, and combining targeted therapies with AC producing enhanced anti-tumor effect. In this review the current panel of available antiangiogenic therapies for the treatment of HCC have been analyzed. In addition current clinical trials are also reported herein.

Rationally Designed Peptides and Peptidomimetics as Inhibitors of Amyloid-β (Aβ) Aggregation: Potential Therapeutics of Alzheimer's Disease.

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Goyal, Deepti; Shuaib, Suniba; Mann, Sukhmani; Goyal, Bhupesh

2017-02-13

Alzheimer's disease (AD) is a progressive neurodegenerative disease with no clinically accepted treatment to cure or halt its progression. The worldwide effort to develop peptide-based inhibitors of amyloid-β (Aβ) aggregation can be considered an unplanned combinatorial experiment. An understanding of what has been done and achieved may advance our understanding of AD pathology and the discovery of effective therapeutic agents. We review here the history of such peptide-based inhibitors, including those based on the Aβ sequence and those not derived from that sequence, containing both natural and unnatural amino acid building blocks. Peptide-based aggregation inhibitors hold significant promise for future AD therapy owing to their high selectivity, effectiveness, low toxicity, good tolerance, low accumulation in tissues, high chemical and biological diversity, possibility of rational design, and highly developed methods for analyzing their mode of action, proteolytic stability (modified peptides), and blood-brain barrier (BBB) permeability.

Computational drug design strategies applied to the modelling of human immunodeficiency virus-1 reverse transcriptase inhibitors

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Lucianna Helene Santos

2015-11-01

Full Text Available Reverse transcriptase (RT is a multifunctional enzyme in the human immunodeficiency virus (HIV-1 life cycle and represents a primary target for drug discovery efforts against HIV-1 infection. Two classes of RT inhibitors, the nucleoside RT inhibitors (NRTIs and the nonnucleoside transcriptase inhibitors are prominently used in the highly active antiretroviral therapy in combination with other anti-HIV drugs. However, the rapid emergence of drug-resistant viral strains has limited the successful rate of the anti-HIV agents. Computational methods are a significant part of the drug design process and indispensable to study drug resistance. In this review, recent advances in computer-aided drug design for the rational design of new compounds against HIV-1 RT using methods such as molecular docking, molecular dynamics, free energy calculations, quantitative structure-activity relationships, pharmacophore modelling and absorption, distribution, metabolism, excretion and toxicity prediction are discussed. Successful applications of these methodologies are also highlighted.

Toxic isolectins from the mushroom Boletus venenatus.

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Horibe, Masashi; Kobayashi, Yuka; Dohra, Hideo; Morita, Tatsuya; Murata, Takeomi; Usui, Taichi; Nakamura-Tsuruta, Sachiko; Kamei, Masugu; Hirabayashi, Jun; Matsuura, Masanori; Yamada, Mina; Saikawa, Yoko; Hashimoto, Kimiko; Nakata, Masaya; Kawagishi, Hirokazu

2010-04-01

Ingestion of the toxic mushroom Boletus venenatus causes a severe gastrointestinal syndrome, such as nausea, repetitive vomiting, diarrhea, and stomachache. A family of isolectins (B. venenatus lectins, BVLs) was isolated as the toxic principles from the mushroom by successive 80% ammonium sulfate-precipitation, Super Q anion-exchange chromatography, and TSK-gel G3000SW gel filtration. Although BVLs showed a single band on SDS-PAGE, they were further divided into eight isolectins (BVL-1 to -8) by BioAssist Q anion-exchange chromatography. All the isolectins showed lectin activity and had very similar molecular weights as detected by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis. Among them, BVL-1 and -3 were further characterized with their complete amino acid sequences of 99 amino acids determined and found to be identical to each other. In the hemagglutination inhibition assay, both proteins failed to bind to any mono- or oligo-saccharides tested and showed the same sugar-binding specificity to glycoproteins. Among the glycoproteins examined, asialo-fetuin was the strongest inhibitor. The sugar-binding specificity of each isolectin was also analyzed by using frontal affinity chromatography and surface plasmon resonance analysis, indicating that they recognized N-linked sugar chains, especially Galbeta1-->4GlcNAcbeta1-->4Manbeta1-->4GlcNAcbeta1-->4GlcNAc (Type II) residues in N-linked sugar chains. BVLs ingestion resulted in fatal toxicity in mice upon intraperitoneal administration and caused diarrhea upon oral administration in rats. Copyright 2009 Elsevier Ltd. All rights reserved.

Hydrogen Peroxide Toxicity Induces Ras Signaling in Human Neuroblastoma SH-SY5Y Cultured Cells

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Jirapa Chetsawang

2010-01-01

Full Text Available It has been reported that overproduction of reactive oxygen species occurs after brain injury and mediates neuronal cells degeneration. In the present study, we examined the role of Ras signaling on hydrogen peroxide-induced neuronal cells degeneration in dopaminergic neuroblastoma SH-SY5Y cells. Hydrogen peroxide significantly reduced cell viability in SH-SY5Y cultured cells. An inhibitor of the enzyme that catalyzes the farnesylation of Ras proteins, FTI-277, and a competitive inhibitor of GTP-binding proteins, GDP-beta-S significantly decreased hydrogen peroxide-induced reduction in cell viability in SH-SY5Y cultured cells. The results of this study might indicate that a Ras-dependent signaling pathway plays a role in hydrogen peroxide-induced toxicity in neuronal cells.

Thyroid cancer in toxic and non-toxic multinodular goiter

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Cerci C

2007-01-01

Full Text Available Background : Many authors have claimed that hyperthyroidism protects against thyroid cancer and believed that the incidence of malignancy is lower in patients with toxic multinodular goiter (TMG than in those with non-toxic multinodular goiter. But in recent studies, it was reported that the incidence of malignancy with TMG is not as low as previously thought. Aim : To compare the thyroid cancer incidence in patients with toxic and non-toxic multinodular goiter. Settings and Design : Histology reports of patients treated surgically with a preoperative diagnosis of toxic and non-toxic multinodular goiter were reviewed to identify the thyroid cancer incidence. Patients having a history of neck irradiation or radioactive iodine therapy were excluded from the study. Materials and Methods : We reviewed 294 patients operated between 2001-2005 from toxic and non-toxic multinodular goiter. One hundred and twenty-four of them were toxic and 170 were non-toxic. Hyperthyroidism was diagnosed by elevated tri-iodothyroinine / thyroxine ratios and low thyroid-stimulating hormone with clinical signs and symptoms. All patients were evaluated with ultrasonography and scintigraphy and fine needle aspiration biopsy. Statistical Analysis Used : Significance of the various parameters was calculated by using ANOVA test. Results : The incidence of malignancy was 9% in the toxic and 10.58% in the non-toxic multinodular goiter group. Any significant difference in the incidence of cancer and tumor size between the two groups could not be detected. Conclusions : The incidence of malignancy in toxic multinodular goiter is not very low as thought earlier and is nearly the same in non-toxic multinodular goiter.

Disease-modifying anti-Alzheimer's drugs: inhibitors of human cholinesterases interfering with β-amyloid aggregation.

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Brogi, Simone; Butini, Stefania; Maramai, Samuele; Colombo, Raffaella; Verga, Laura; Lanni, Cristina; De Lorenzi, Ersilia; Lamponi, Stefania; Andreassi, Marco; Bartolini, Manuela; Andrisano, Vincenza; Novellino, Ettore; Campiani, Giuseppe; Brindisi, Margherita; Gemma, Sandra

2014-07-01

We recently described multifunctional tools (2a-c) as potent inhibitors of human Cholinesterases (ChEs) also able to modulate events correlated with Aβ aggregation. We herein propose a thorough biological and computational analysis aiming at understanding their mechanism of action at the molecular level. We determined the inhibitory potency of 2a-c on Aβ1-42 self-aggregation, the interference of 2a with the toxic Aβ oligomeric species and with the postaggregation states by capillary electrophoresis analysis and transmission electron microscopy. The modulation of Aβ toxicity was assessed for 2a and 2b on human neuroblastoma cells. The key interactions of 2a with Aβ and with the Aβ-preformed fibrils were computationally analyzed. 2a-c toxicity profile was also assessed (human hepatocytes and mouse fibroblasts). Our prototypical pluripotent analogue 2a interferes with Aβ oligomerization process thus reducing Aβ oligomers-mediated toxicity in human neuroblastoma cells. 2a also disrupts preformed fibrils. Computational studies highlighted the bases governing the diversified activities of 2a. Converging analytical, biological, and in silico data explained the mechanism of action of 2a on Aβ1-42 oligomers formation and against Aβ-preformed fibrils. This evidence, combined with toxicity data, will orient the future design of safer analogues. © 2014 John Wiley & Sons Ltd.

Effects of chronic Akt/mTOR inhibition by rapamycin on mechanical overload-induced hypertrophy and myosin heavy chain transition in masseter muscle.

Science.gov (United States)

Umeki, Daisuke; Ohnuki, Yoshiki; Mototani, Yasumasa; Shiozawa, Kouichi; Fujita, Takayuki; Nakamura, Yoshiki; Saeki, Yasutake; Okumura, Satoshi

2013-01-01

To examine the effects of the Akt/mammalian target of rapamycin (mTOR) pathway on masseter muscle hypertrophy and myosin heavy chain (MHC) transition in response to mechanical overload, we analyzed the effects of bite-opening (BO) on the hypertrophy and MHC composition of masseter muscle of BO-rats treated or not treated with rapamycin (RAPA), a selective mTOR inhibitor. The masseter muscle weight in BO-rats was significantly greater than that in controls, and this increase was attenuated by RAPA treatment. Expression of slow-twitch MHC isoforms was significantly increased in BO-rats with/without RAPA treatment, compared with controls, but the magnitude of the increase was much smaller in RAPA-treated BO-rats. Phosphorylation of p44/42 MAPK (ERK1/2), which preserves fast-twitch MHC isoforms in skeletal muscle, was significantly decreased in BO-rats, but the decrease was abrogated by RAPA treatment. Calcineurin signaling is known to be important for masseter muscle hypertrophy and fast-to-slow MHC isoform transition, but expression of known calcineurin activity modulators was unaffected by RAPA treatment. Taken together, these results indicate that the Akt/mTOR pathway is involved in both development of masseter muscle hypertrophy and fast-to-slow MHC isoform transition in response to mechanical overload with inhibition of the ERK1/2 pathway and operates independently of the calcineurin pathway.

Expression and Immunohistochemical Localisation of the G beta gamma activated and Calcineurin-inhibited Adenylyl Cyclase Isoforms in Rat Articular Chondrocytes

International Nuclear Information System (INIS)

Memon, I.; Khan, K.M.; Siddiqui, S.; Perveen, S.; Ishaq, M.

2016-01-01

Objective: To determine the expression and localisation of the Gβγ-activated adenylyl cyclase (AC) isoforms 2, 4, and 7 and calcineurin-inhibited AC isoform 9 in rat articular chondrocytes. Study Design: Experimental study. Place and Duration of Study: Jumma Research Laboratory and Histology Laboratory, The Aga Khan University, Karachi, from 2009 to 2011. Methodology: Fresh slices of articular cartilage were taken from various synovial joints of rats of different age groups. The expression of AC isoforms was determined by RT-PCR and immunohistochemistry was performed to localise these isoforms in articular chondrocytes. Tissue sections were processed for immunostaining with respective antibodies. The color was developed by diaminobenzidine. Results: All the studied AC isoforms were found to be differentially expressed in different zones of the rat articular cartilage. Generally, expression of all AC isoforms studied increased with age. The expression of the AC isoforms through PCR was almost consistent with the localisation of these isoforms by immunohistochemistry. Conclusion: These data add to the information about signalling cascades possibly involved in articular chondrocytes. Variable expression of AC isoforms 2, 4, 7, and 9 suggest a role for the signalling cascades regulated by the AC isoforms in articular chondrocytes. (author)

Herbicide toxicity on river biofilms assessed by pulse amplitude modulated (PAM) fluorometry

Energy Technology Data Exchange (ETDEWEB)

Kim Tiam, Sandra, E-mail: sandra.kimtiam@gmail.com [Irstea, UR EABX, 50 Avenue de Verdun, F-33612, Cestas Cedex (France); Université de Bordeaux, EPOC, UMR 5805, F-33120 Arcachon (France); Laviale, Martin [Departamento de Biologia and CESAM – Centro de Estudos do Ambiente e do Mar Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); Sorbonne Universités, UPMC Univ Paris 06, UMR 7093, LOV, Observatoire Océanologique, F-06230, Villefranche-Sur-Mer (France); CNRS, UMR 7093, LOV, Observatoire Océanologique, F-06230, Villefranche-Sur-Mer France (France); Feurtet-Mazel, Agnès [Université de Bordeaux, EPOC, UMR 5805, F-33120 Arcachon (France); Jan, Gwilherm [Irstea, UR EABX, 50 Avenue de Verdun, F-33612, Cestas Cedex (France); Gonzalez, Patrice [Université de Bordeaux, EPOC, UMR 5805, F-33120 Arcachon (France); Mazzella, Nicolas; Morin, Soizic [Irstea, UR EABX, 50 Avenue de Verdun, F-33612, Cestas Cedex (France)

2015-08-15

Highlights: • Rapid Light Curves were shown to be early markers of toxicant exposure. • Diuron and norflurazon effects were significant at environmentally realistic concentrations. • Toxic effects in intact biofilms seem to be delayed compared to disrupted biofilms. - Abstract: The use of Rapid light curves (RLCs) as a toxicity endpoint for river biofilms was examined in this study and compared to “classical fluorescence parameters” i.e. minimal fluorescence (F{sub 0}), optimal and effective quantum yields of photosystem II (F{sub v}/F{sub m} and Φ{sub PSII}). Measurements were performed after exposure to five concentrations of diuron (from 0.3 to 33.4 μg L{sup −1}), its main degradation product (DCPMU) (from 1.0 to 1014 μg L{sup −1}) and norflurazon (from 0.6 to 585 μg L{sup −1}) with the lowest exposure concentrations corresponding to levels regularly encountered in chronically contaminated sites. Biofilm responses were evaluated after 1, 5, 7 and 14 days of exposure to the different toxicants. Overall, the responses of both “classical fluorescence parameters” and RLC endpoints were highly time dependent and related to the mode of action of the different compounds. Interestingly, parameters calculated from RLCs (α, ETR{sub max} and I{sub k}) were useful early markers of pesticide exposure since they revealed significant effects of all the tested toxicants from the first day of exposure. In comparison, classical fluorescence endpoints (F{sub 0} and F{sub v}/F{sub m}) measured at day 1 were only affected in the DCPMU treatment. Our results demonstrated the interest of RLCs as early markers of toxicant exposure particularly when working with toxicants with less specific mode of action than PSII inhibitors.

Can the tyrosine kinase inhibitors trigger metabolic encephalopathy in cirrhotic patients?

Science.gov (United States)

Brandi, Giovanni; de Rosa, Francesco; Calzà, Laura; Girolamo, Stefania Di; Tufoni, Manuel; Ricci, Carmen Serena; Cirignotta, Fabio; Caraceni, Paolo; Biasco, Guido

2013-03-01

Sorafenib is the standard treatment of advanced hepatocarcinoma (HCC) in cirrhotic patients with preserved liver function. It shares many adverse effects with other tyrosine-kinase (TK) inhibitors and antiangiogenic drugs. TK inhibitors could have a direct toxicity on CNS, both by interfering with TK-related pathways and by inhibiting angiogenesis. The aim of this study was to investigate whether sorafenib administration can be associated to metabolic encephalopathy in patients with cirrhosis. We retrospectively reviewed medical records of all cirrhotic patients treated with sorafenib for HCC afferent at our Department from January 2009 to December 2011. Among 62 patients, we identified 10 patients with clinically significant cognitive impairment. Seven of these were clearly diagnosed with overt hepatic encephalopathy (HE), one with brain metastases and two with drug-related toxic-metabolic encephalopathy. These last two cases were characterized by severe cognitive impairment, mood alteration and memory deficit. Clinical exam, blood tests and brain CT excluded organic causes of encephalopathy and precipitating factors of HE. Sorafenib discontinuation was associated with complete reversal of the syndrome, which recurred on drug re-administration in one case. Our study suggests that sorafenib may be a precipitating factor of metabolic encephalopathy in cirrhotic patients with advanced HCC. This neurological syndrome appears to be not responsive to the conventional treatment for HE, but it is fully reversible by drug discontinuation. It can be speculated that the potential direct neuronal action of sorafenib may represent a trigger for the onset of metabolic encephalopathy in a subset of cirrhotic patients. © 2012 John Wiley & Sons A/S.

Efflux pump inhibitors (EPIs as new antimicrobial agents against Pseudomonas aeruginosa

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Momen Askoura

2011-05-01

Full Text Available Pseudomonas aeruginosa is an opportunistic human pathogen and one of the leading causes of nosocomial infections worldwide. The difficulty in treatment of pseudomonas infections arises from being multidrug resistant (MDR and exhibits resistance to most antimicrobial agents due to the expression of different mechanisms overcoming their effects. Of these resistance mechanisms, the active efflux pumps in Pseudomonas aeruginosa that belong to the resistance nodulation division (RND plays a very important role in extruding the antibiotics outside the bacterial cells providing a protective means against their antibacterial activity. Beside its role against the antimicrobial agents, these pumps can extrude biocides, detergents, and other metabolic inhibitors. It is clear that efflux pumps can be targets for new antimicrobial agents. Peptidomimetic compounds such as phenylalanine arginyl β-naphthylamide (PAβN have been introduced as efflux pump inhibitors (EPIs; their mechanism of action is through competitive inhibition with antibiotics on the efflux pump resulting in increased intracellular concentration of antibiotic, hence, restoring its antibacterial activity. The advantage of EPIs is the difficulty to develop bacterial resistance against them, but the disadvantage is their toxic property hindering their clinical application. The structure activity relationship of these compounds showed other derivatives from PAβN that are higher in their activity with higher solubility in biological fluids and decreased toxicity level. This raises further questions on how can we compact Pseudomonas infections. Of particular importance, the recent resurgence in the use of older antibiotics such as polymyxins and probably applying stricter control measures in order to prevent their spread in clinical sittings.

A Phase 1 trial of the poly(ADP-ribose) polymerase inhibitor olaparib (AZD2281) in combination with the anti-angiogenic cediranib (AZD2171) in recurrent epithelial ovarian or triple-negative breast cancer.

Science.gov (United States)

Liu, Joyce F; Tolaney, Sara M; Birrer, Michael; Fleming, Gini F; Buss, Mary K; Dahlberg, Suzanne E; Lee, Hang; Whalen, Christin; Tyburski, Karin; Winer, Eric; Ivy, Percy; Matulonis, Ursula A

2013-09-01

Poly(ADP-ribose) polymerase (PARP)-inhibitors and anti-angiogenics have activity in recurrent ovarian and breast cancer; however, the effect of combined therapy against PARP and angiogenesis in this population has not been reported. We investigated the toxicities and recommended phase 2 dosing (RP2D) of the combination of cediranib, a multitargeted inhibitor of vascular endothelial growth factor receptor (VEGFR)-1/2/3 and olaparib, a PARP-inhibitor (NCT01116648). Cediranib tablets once daily and olaparib capsules twice daily were administered orally in a standard 3+3 dose escalation design. Patients with recurrent ovarian or metastatic triple-negative breast cancer were eligible. Patients had measurable disease by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 or met Gynecologic Cancer InterGroup (GCIG) CA125 criteria. No prior PARP-inhibitors or anti-angiogenics in the recurrent setting were allowed. 28 patients (20 ovarian, 8 breast) enrolled to 4 dose levels. 2 dose limiting toxicities (DLTs) (1 grade 4 neutropenia ≥ 4 days; 1 grade 4 thrombocytopenia) occurred at the highest dose level (cediranib 30 mg daily; olaparib 400 mg twice daily [BID]). The RP2D was cediranib 30 mg daily and olaparib 200 mg BID. Grade 3 or higher toxicities occurred in 75% of patients, and included grade 3 hypertension (25%) and grade 3 fatigue (18%). One grade 3 bowel obstruction occurred. The overall response rate (ORR) in the 18 RECIST-evaluable ovarian cancer patients was 44%, with a clinical benefit rate (ORR plus stable disease (SD) > 24 weeks) of 61%. None of the seven evaluable breast cancer patients achieved clinical response; two patients had stable disease for > 24 weeks. The combination of cediranib and olaparib has haematologic DLTs and anticipated class toxicities, with promising evidence of activity in ovarian cancer patients. Copyright © 2013 Elsevier Ltd. All rights reserved.

The validation of corrosion inhibitors for ancillary cooling systems at Sizewell B PWR

International Nuclear Information System (INIS)

Allan, S.J.; Garnsey, R.; Lawson, W.F.

1994-01-01

Sizewell B has several low temperature ancillary cooling circuits for removing low grade heat. One of the principal circuits is the Component Cooling Water System (CCWS) primarily constructed from carbon steel pipework but also containing stainless steel, titanium, copper and cupronickel components. Linked to the CCWS is another carbon steel system namely the Reserve Ultimate Heat Sink (RUHS) a system unique to Sizewell B providing an independent heat removal capability for the CCWS as a safety back-up. Both systems utilize demineralized water with the addition of an inhibitor to prevent corrosion. The vendor recommended inhibitor namely potassium chromate is highly toxic to marine life and initial discussions with the regulatory authorities indicated that it would be extremely difficult to obtain a discharge consent to cover leakage or potential system purges and dumps associated with maintenance operations. Thus an alternative was sought. Sodium nitrite (anhydrous NaN0 2 )/borax (Na 2 B 4 0 7 1OH 2 0) inhibitor solutions have been used for many years in the power industry for preservation of carbon steel plant and several proprietary formulations are based on this mixture. There has been extensive test work in the UK on this inhibitor for secondary side boiler storage on gas reactors and therefore it was considered a prime candidate for use at Sizewell B. Starting in 1985 a programme of work sponsored by Nuclear Electric plc has been completed by NNC Ltd to compare nitrite/borax with other suitable inhibitors and validate its use for Sizewell B. (authors). 5 figs., 1 tab

High resolution crystal structure of rat long chain hydroxy acid oxidase in complex with the inhibitor 4-carboxy-5-[(4-chlorophenyl)sulfanyl]-1, 2, 3-thiadiazole. Implications for inhibitor specificity and drug design

Energy Technology Data Exchange (ETDEWEB)

Chen, Zhi-wei; Vignaud, Caroline; Jaafar, Adil; Lévy, Bernard; Guéritte, Françoise; Guénard, Daniel; Lederer, Florence; Mathews, F. Scott (CNRS-UMR); (WU-MED)

2012-05-24

Long chain hydroxy acid oxidase (LCHAO) is responsible for the formation of methylguanidine, a toxic compound with elevated serum levels in patients with chronic renal failure. Its isozyme glycolate oxidase (GOX), has a role in the formation of oxalate, which can lead to pathological deposits of calcium oxalate, in particular in the disease primary hyperoxaluria. Inhibitors of these two enzymes may have therapeutic value. These enzymes are the only human members of the family of FMN-dependent L-2-hydroxy acid-oxidizing enzymes, with yeast flavocytochrome b{sub 2} (Fcb2) among its well studied members. We screened a chemical library for inhibitors, using in parallel rat LCHAO, human GOX and the Fcb2 flavodehydrogenase domain (FDH). Among the hits was an inhibitor, CCPST, with an IC{sub 50} in the micromolar range for all three enzymes. We report here the crystal structure of a complex between this compound and LCHAO at 1.3 {angstrom} resolution. In comparison with a lower resolution structure of this enzyme, binding of the inhibitor induces a conformational change in part of the TIM barrel loop 4, as well as protonation of the active site histidine. The CCPST interactions are compared with those it forms with human GOX and those formed by two other inhibitors with human GOX and spinach GOX. These compounds differ from CCPST in having the sulfur replaced with a nitrogen in the five-membered ring as well as different hydrophobic substituents. The possible reason for the {approx}100-fold difference in affinity between these two series of inhibitors is discussed. The present results indicate that specificity is an issue in the quest for therapeutic inhibitors of either LCHAO or GOX, but they may give leads for this quest.

Mosquitocidal carbamates with low toxicity to agricultural pests: an advantageous property for insecticide resistance management.

Science.gov (United States)

Swale, Daniel R; Carlier, Paul R; Hartsel, Joshua A; Ma, Ming; Bloomquist, Jeffrey R

2015-08-01

Insecticide resistance in the malaria mosquito Anopheles gambiae is well documented, and widespread agricultural use of pyrethroids may exacerbate development of resistance when pyrethroids are used in vector control. We have developed carbamate anticholinesterases that possess a high degree of An. gambiae:human selectivity for enzyme inhibition. The purpose of this study was to assess the spectrum of activity of these carbamates against other mosquitoes and agricultural pests. Experimental carbamates were potent inhibitors of mosquito acetylcholinesterases, with IC50 values in the nanomolar range. Similar potencies were observed for Musca domestica and Drosophila melanogaster enzymes. Although meta-substituted carbamates were potent inhibitors, two ortho-substituted carbamates displayed poor enzyme inhibition (IC50 ≥ 10(-6)  M) in honey bee (Apis mellifera), Asian citrus psyllid (Diaphorina citri) and lepidopteran agricultural pests (Plutella xylostella and Ostrinia nubilalis). Enzyme inhibition results were confirmed by toxicity studies in caterpillars, where the new carbamates were 2-3-fold less toxic than propoxur and up to tenfold less active than bendiocarb, indicating little utility of these compounds for crop protection. The experimental carbamates were broadly active against mosquito species but not agricultural pests, which should mitigate selection for mosquito insecticide resistance by reducing agricultural uses of these compounds. © 2014 Society of Chemical Industry. © 2014 Society of Chemical Industry.

Using Bioassays and Species Sensitivity Distributions to Assess Herbicide Toxicity towards Benthic Diatoms

Science.gov (United States)

Larras, Floriane; Bouchez, Agnès; Rimet, Frédéric; Montuelle, Bernard

2012-01-01

Although benthic diatoms are widely used in ecological studies of aquatic systems, there is still a dearth of data concerning species sensitivities towards several contaminants. Within the same community, different species may respond differently depending on their physiological and ecological characteristics. This lack of knowledge makes specific appropriate risk assessment impossible. To find out whether species sensitivity distribution (SSD) could be used to estimate the risk of herbicide toxicity for diatoms, we need to know whether their sensitivity depends on their physiological and ecological characteristics. We carried out single-species bioassays on 11 diatom species exposed to 8 herbicides. Dose-responses relationships were used to extrapolate the Effective Concentration 5 (EC5) and the Effective Concentration 50 (EC50) for each exposure. These data were used to fit a SSD curve for each herbicide, and to determine the Hazardous concentration 5 (HC5) and 50 (HC50). Our results revealed a high level of variability of the sensitivity in the set of species tested. For photosystem-II inhibitor (PSII) herbicides, diatoms species displayed a typical grouping of sensitivity levels consistent with their trophic mode and their ecological guild. N-heterotroph and “motile” guild species were more tolerant of PSII inhibitors, while N-autotroph and “low profile” guild species were more sensitive. Comprehensive SSD curves were obtained for 5 herbicides, but not for sulfonylurea herbicides or for dimetachlor, which had toxicity levels that were below the range of concentration tested. The SSD curves provided the following ranking of toxicity: diuron> terbutryn> isoproturon> atrazine> metolachlor. The HC that affected 5% of the species revealed that, even at the usual environmental concentrations of herbicides, diatom assemblages could be affected, especially by isoproturon, terbutryn, and diuron. PMID:22952981

Using bioassays and species sensitivity distributions to assess herbicide toxicity towards benthic diatoms.

Directory of Open Access Journals (Sweden)

Floriane Larras

Full Text Available Although benthic diatoms are widely used in ecological studies of aquatic systems, there is still a dearth of data concerning species sensitivities towards several contaminants. Within the same community, different species may respond differently depending on their physiological and ecological characteristics. This lack of knowledge makes specific appropriate risk assessment impossible. To find out whether species sensitivity distribution (SSD could be used to estimate the risk of herbicide toxicity for diatoms, we need to know whether their sensitivity depends on their physiological and ecological characteristics. We carried out single-species bioassays on 11 diatom species exposed to 8 herbicides. Dose-responses relationships were used to extrapolate the Effective Concentration 5 (EC(5 and the Effective Concentration 50 (EC(50 for each exposure. These data were used to fit a SSD curve for each herbicide, and to determine the Hazardous concentration 5 (HC(5 and 50 (HC(50. Our results revealed a high level of variability of the sensitivity in the set of species tested. For photosystem-II inhibitor (PSII herbicides, diatoms species displayed a typical grouping of sensitivity levels consistent with their trophic mode and their ecological guild. N-heterotroph and "motile" guild species were more tolerant of PSII inhibitors, while N-autotroph and "low profile" guild species were more sensitive. Comprehensive SSD curves were obtained for 5 herbicides, but not for sulfonylurea herbicides or for dimetachlor, which had toxicity levels that were below the range of concentration tested. The SSD curves provided the following ranking of toxicity: diuron> terbutryn> isoproturon> atrazine> metolachlor. The HC that affected 5% of the species revealed that, even at the usual environmental concentrations of herbicides, diatom assemblages could be affected, especially by isoproturon, terbutryn, and diuron.

Toxicity of polyhydroxylated fullerene to mitochondria

Energy Technology Data Exchange (ETDEWEB)

Yang, Li-Yun [State Key Laboratory of Virology & Key Laboratory of Analytical Chemistry for Biology and Medicine (MOE), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Gao, Jia-Ling [Department of Chemistry, College of Chemistry and Environmental Engineering, Yangtze University, Jingzhou 434023 (China); Gao, Tian; Dong, Ping; Ma, Long; Jiang, Feng-Lei [State Key Laboratory of Virology & Key Laboratory of Analytical Chemistry for Biology and Medicine (MOE), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Liu, Yi, E-mail: yiliuchem@whu.edu.cn [State Key Laboratory of Virology & Key Laboratory of Analytical Chemistry for Biology and Medicine (MOE), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China)

2016-01-15

Highlights: • Fullerenol-induced mitochondrial dysfunction was investigated at mitochondrial level. • Fullerenol disturbed mitochondrial inner membrane in polar protein regions. • Fullerenol affected the inner membrane and respiration chain of mitochondria. - Abstract: Mitochondrial dysfunction is considered as a crucial mechanism of nanomaterial toxicity. Herein, we investigated the effects of polyhydroxylated fullerene (C{sub 60}(OH){sub 44}, fullerenol), a model carbon-based nanomaterial with high water solubility, on isolated mitochondria. Our study demonstrated that fullerenol enhanced the permeabilization of mitochondrial inner membrane to H{sup +} and K{sup +} and induced mitochondrial permeability transition (MPT). The fullerenol-induced swelling was dose-dependent and could be effectively inhibited by MPT inhibitors such as cyclosporin A (CsA), adenosine diphosphate (ADP), ruthenium red (RR) and ethylenediaminetetraacetic acid (EDTA). After treating the mitochondria with fullerenol, the mitochondrial membrane potential (MMP) was found collapsed in a concentration-independent manner. The fluorescence anisotropy of hematoporphyrin (HP) changed significantly with the addition of fullerenol, while that of 1,6-diphenyl-hexatriene (DPH) changed slightly. Moreover, a decrease of respiration state 3 and increase of respiration state 4 were observed when mitochondria were energized with complex II substrate succinate. The results of transmission electron microscopy (TEM) provided direct evidence that fullerenol damaged the mitochondrial ultrastructure. The investigations can provide comprehensive information to elucidate the possible toxic mechanism of fullerenols at subcellular level.

Aristolochic acid and its derivatives as inhibitors of snake venom L-amino acid oxidase.

Science.gov (United States)

Bhattacharjee, Payel; Bera, Indrani; Chakraborty, Subhamoy; Ghoshal, Nanda; Bhattacharyya, Debasish

2017-11-01

Snake venom L-amino acid oxidase (LAAO) exerts toxicity by inducing hemorrhage, pneumorrhagia, pulmonary edema, cardiac edema, liver cell necrosis etc. Being well conserved, inhibitors of the enzyme may be synthesized using the template of the substrate, substrate binding site and features of the catalytic site of the enzyme. Previous findings showed that aristolochic acid (AA), a major constituent of Aristolochia indica, inhibits Russell's viper venom LAAO enzyme activity since, AA interacts with DNA and causes genotoxicity, derivatives of this compound were synthesized by replacing the nitro group to reduce toxicity while retaining the inhibitory potency. The interactions of AA and its derivatives with LAAO were followed by inhibition kinetics and surface plasmon resonance. Similar interactions with DNA were followed by absorption spectroscopy and atomic force microscopy. LAAO-induced cytotoxicity was evaluated by generation of reactive oxygen species (ROS), cell viability assays, confocal and epifluorescence microscopy. The hydroxyl (AA-OH) and chloro (AA-Cl) derivatives acted as inhibitors of LAAO but did not interact with DNA. The derivatives significantly reduced LAAO-induced ROS generation and cytotoxicity in human embryonic kidney (HEK 293) and hepatoma (HepG2) cell lines. Confocal images indicated that AA, AA-OH and AA-Cl interfered with the binding of LAAO to the cell membrane. AA-OH and AA-Cl significantly inhibited LAAO activity and reduced LAAO-induced cytotoxicity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Modulatory effect of curcumin on ketamine-induced toxicity in rat thymocytes: Involvement of reactive oxygen species (ROS and the phosphoinositide 3-kinase (PI3K/protein kinase B (Akt pathway

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Svetlana Pavlovic

2018-03-01

Full Text Available Ketamine is a widely used anesthetic in pediatric clinical practice. Previous studies have demonstrated that ketamine induces neurotoxicity and has a modulatory effect on the cells of the immune system. Here, we evaluated the potential protective effect and underlying mechanisms of natural phenolic compound curcumin against ketamine-induced toxicity in rat thymocytes. Rat thymocytes were exposed to 100 µM ketamine alone or combined with increasing concentrations of curcumin (0.3, 1, and 3 μM for 24 hours. Cell viability was analyzed with CCK-8 assay kit. Apoptosis was analyzed using flow cytometry and propidium iodide as well as Z-VAD-FMK and Z-LEHD-FMK inhibitors. Reactive oxygen species (ROS production and mitochondrial membrane potential [MMP] were measured by flow cytometry. Colorimetric assay with DEVD-pNA substrate was used for assessing caspase-3 activity. Involvement of phosphoinositide 3-kinase (PI3K/protein kinase B (Akt signaling pathway was tested with Wortmannin inhibitor. Ketamine induced toxicity in cells, increased the number of hypodiploid cells, caspase-3 activity and ROS production, and inhibited the MMP. Co-incubation of higher concentrations of curcumin (1 and 3 μM with ketamine markedly decreased cytotoxicity, apoptosis rate, caspase-3 activity, and ROS production in rat thymocytes, and increased the MMP. Application of Z-VAD-FMK (a pan caspase inhibitor or Z-LEHD-FMK (caspase-9 inhibitor with ketamine effectively attenuated the ketamine-induced apoptosis in rat thymocytes. Administration of Wortmannin (a PI3K inhibitor with curcumin and ketamine significantly decreased the protective effect of curcumin on rat thymocytes. Our results indicate that ketamine-induced toxicity in rat thymocytes mainly occurs through the mitochondria-mediated apoptotic pathway and that the PI3K/Akt signaling pathway is involved in the anti-apoptotic effect of curcumin.

Role of oxidative stress in methamphetamine-induced dopaminergic toxicity mediated by protein kinase Cδ.

Science.gov (United States)

Shin, Eun-Joo; Duong, Chu Xuan; Nguyen, Xuan-Khanh Thi; Li, Zhengyi; Bing, Guoying; Bach, Jae-Hyung; Park, Dae Hun; Nakayama, Keiichi; Ali, Syed F; Kanthasamy, Anumantha G; Cadet, Jean Lud; Nabeshima, Toshitaka; Kim, Hyoung-Chun

2012-06-15

This study examined the role of protein kinase C (PKC) isozymes in methamphetamine (MA)-induced dopaminergic toxicity. Multiple-dose administration of MA did not significantly alter PKCα, PKCβI, PKCβII, or PKCζ expression in the striatum, but did significantly increase PKCδ expression. Gö6976 (a co-inhibitor of PKCα and -β), hispidin (PKCβ inhibitor), and PKCζ pseudosubstrate inhibitor (PKCζ inhibitor) did not significantly alter MA-induced behavioral impairments. However, rottlerin (PKCδ inhibitor) significantly attenuated behavioral impairments in a dose-dependent manner. In addition, MA-induced behavioral impairments were not apparent in PKCδ knockout (-/-) mice. MA-induced oxidative stress (i.e., lipid peroxidation and protein oxidation) was significantly attenuated in rottlerin-treated mice and was not apparent in PKCδ (-/-) mice. Consistent with this, MA-induced apoptosis (i.e., terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive apoptotic cells) was significantly attenuated in rottlerin-treated mice. Furthermore, MA-induced increases in the dopamine (DA) turnover rate and decreases in tyrosine hydroxylase (TH) activity and the expression of TH, dopamine transporter (DAT), and vesicular monoamine transporter 2 (VMAT2) were not significantly observed in rottlerin-treated or PKCδ (-/-) mice. Our results suggest that PKCδ gene expression is a key mediator of oxidative stress and dopaminergic damage induced by MA. Thus, inhibition of PKCδ may be a useful target for protection against MA-induced neurotoxicity. Copyright © 2012 Elsevier B.V. All rights reserved.

Redox-Active Selenium Compounds—From Toxicity and Cell Death to Cancer Treatment

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Sougat Misra

2015-05-01

Full Text Available Selenium is generally known as an antioxidant due to its presence in selenoproteins as selenocysteine, but it is also toxic. The toxic effects of selenium are, however, strictly concentration and chemical species dependent. One class of selenium compounds is a potent inhibitor of cell growth with remarkable tumor specificity. These redox active compounds are pro-oxidative and highly cytotoxic to tumor cells and are promising candidates to be used in chemotherapy against cancer. Herein we elaborate upon the major forms of dietary selenium compounds, their metabolic pathways, and their antioxidant and pro-oxidant potentials with emphasis on cytotoxic mechanisms. Relative cytotoxicity of inorganic selenite and organic selenocystine compounds to different cancer cells are presented as evidence to our perspective. Furthermore, new novel classes of selenium compounds specifically designed to target tumor cells are presented and the potential of selenium in modern oncology is extensively discussed.

Long-Term Impact of Cyclosporin Reduction with MMF Treatment in Chronic Allograft Dysfunction: REFERENECE Study 3-Year Follow Up

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L. Frimat

2010-01-01

Full Text Available Calcineurin inhibitor (CNI toxicity contributes to chronic allograft nephropathy (CAN. In the 2-year, randomized, study, we showed that 50% cyclosporin (CsA reduction in combination with mycophenolate mofetil (MMF treatment improves kidney function without increasing the risk for graft rejection/loss. To investigate the long-term effect of this regimen, we conducted a follow up study in 70 kidney transplant patients until 5 years after REFERENCE initiation. The improvement of kidney function was confirmed in the MMF group but not in the control group (CsA group. Four graft losses occurred, 2 in each group (graft survival in the MMF group 95.8% and 90.9% in control group. One death occurred in the control group. There was no statistically significant difference in the occurrence of serious adverse events or acute graft rejections. A limitation is the weak proportion of patient still remaining within the control group. On the other hand, REFERENCE focuses on the CsA regimen while opinions about the tacrolimus ones are still debated. In conclusion, CsA reduction in the presence of MMF treatment seems to maintain kidney function and is well tolerated in the long term.

Palmoplantar peeling secondary to sirolimus therapy.

Science.gov (United States)

Liu, L S; McNiff, J M; Colegio, O R

2014-01-01

Sirolimus (rapamycin) is an immunosuppressive agent commonly used in transplant recipients. Although sirolimus has less renal toxicity than calcineurin inhibitors, its use has been limited by its side effects. The most common cutaneous pathologies associated with sirolimus are inflammatory acneiform eruptions, lymphedema and aphthous ulcers. We present a novel cutaneous manifestation of sirolimus therapy that limited its use in at least one transplant recipient. Upon commencing sirolimus therapy, four solid organ transplant recipients developed tender, nonpruritic palmoplantar peeling within the first month of therapy. The peeling clinically resembled a mild form of hand-foot syndrome, yet none of the patients had been treated with chemotherapeutics. Desquamation presented on the palms and soles with dry vesicles and minor peeling extending to the dorsal aspects of the hands and feet. Histologically, the lesions were noninflammatory; the epidermis showed subtle separation between keratinocytes, suggesting either spongiosis or a defect in intercellular adhesion. One patient opted to discontinue treatment because of the tenderness associated with the palmoplantar peeling, which resulted in complete resolution within 2 weeks. © Copyright 2013 The American Society of Transplantation and the American Society of Transplant Surgeons.

A rat retinal damage model predicts for potential clinical visual disturbances induced by Hsp90 inhibitors

International Nuclear Information System (INIS)

Zhou, Dan; Liu, Yuan; Ye, Josephine; Ying, Weiwen; Ogawa, Luisa Shin; Inoue, Takayo; Tatsuta, Noriaki; Wada, Yumiko; Koya, Keizo; Huang, Qin; Bates, Richard C.; Sonderfan, Andrew J.

2013-01-01

In human trials certain heat shock protein 90 (Hsp90) inhibitors, including 17-DMAG and NVP-AUY922, have caused visual disorders indicative of retinal dysfunction; others such as 17-AAG and ganetespib have not. To understand these safety profile differences we evaluated histopathological changes and exposure profiles of four Hsp90 inhibitors, with or without clinical reports of adverse ocular effects, using a rat retinal model. Retinal morphology, Hsp70 expression (a surrogate marker of Hsp90 inhibition), apoptotic induction and pharmacokinetic drug exposure analysis were examined in rats treated with the ansamycins 17-DMAG and 17-AAG, or with the second-generation compounds NVP-AUY922 and ganetespib. Both 17-DMAG and NVP-AUY922 induced strong yet restricted retinal Hsp70 up-regulation and promoted marked photoreceptor cell death 24 h after the final dose. In contrast, neither 17-AAG nor ganetespib elicited photoreceptor injury. When the relationship between drug distribution and photoreceptor degeneration was examined, 17-DMAG and NVP-AUY922 showed substantial retinal accumulation, with high retina/plasma (R/P) ratios and slow elimination rates, such that 51% of 17-DMAG and 65% of NVP-AUY922 present at 30 min post-injection were retained in the retina 6 h post-dose. For 17-AAG and ganetespib, retinal elimination was rapid (90% and 70% of drugs eliminated from the retina at 6 h, respectively) which correlated with lower R/P ratios. These findings indicate that prolonged inhibition of Hsp90 activity in the eye results in photoreceptor cell death. Moreover, the results suggest that the retina/plasma exposure ratio and retinal elimination rate profiles of Hsp90 inhibitors, irrespective of their chemical class, may predict for ocular toxicity potential. - Highlights: • In human trials some Hsp90 inhibitors cause visual disorders, others do not. • Prolonged inhibition of Hsp90 in the rat eye results in photoreceptor cell death. • Retina/plasma ratio and retinal

Toward precision medicine with next-generation EGFR inhibitors in non-small-cell lung cancer

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Yap TA

2014-09-01

Full Text Available Timothy A Yap,1,2 Sanjay Popat1,3 1Lung Cancer Unit, Department of Medicine, The Royal Marsden National Health Service Foundation Trust, London, United Kingdom; 2The Institute of Cancer Research, London, United Kingdom; 3National Heart and Lung Institute, London, United Kingdom Abstract: The use of genomics to discover novel targets and biomarkers has placed the field of oncology at the forefront of precision medicine. First-generation epidermal growth factor receptor (EGFR inhibitors have transformed the therapeutic landscape of EGFR mutant non-small-cell lung carcinoma through the genetic stratification of tumors from patients with this disease. Somatic EGFR mutations in lung adenocarcinoma are now well established as predictive biomarkers of response and resistance to small-molecule EGFR inhibitors. Despite early patient benefit, primary resistance and subsequent tumor progression to first-generation EGFR inhibitors are seen in 10%–30% of patients with EGFR mutant non-small-cell lung carcinoma. Acquired drug resistance is also inevitable, with patients developing disease progression after only 10–13 months of antitumor therapy. This review details strategies pursued in circumventing T790M-mediated drug resistance to EGFR inhibitors, which is the most common mechanism of acquired resistance, and focuses on the clinical development of second-generation EGFR inhibitors, exemplified by afatinib (BIBW2992. We discuss the rationale, mechanism of action, clinical efficacy, and toxicity profile of afatinib, including the LUX-Lung studies. We also discuss the emergence of third-generation irreversible mutant-selective inhibitors of EGFR and envision the future management of EGFR mutant lung adenocarcinoma. Keywords: afatinib, EGFR, erlotinib, gefitinib, LUX-Lung, NSCLC 

Dynamin-Related Protein 1 Inhibitors Protect against Ischemic Toxicity through Attenuating Mitochondrial Ca2+ Uptake from Endoplasmic Reticulum Store in PC12 Cells

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Ye Tian

2014-02-01

Full Text Available Intracellular calcium homeostasis disorder and mitochondrial dysfunction are involved in many acute and chronic brain diseases, including ischemic brain injury. An imbalance in mitochondrial fission and fusion is one of the most important structural abnormalities found in a large number of mitochondrial dysfunction related diseases. Here, we investigated the effects of mitochondrial division inhibitor A (mdivi A and mdivi B, two small molecule inhibitors of mitochondrial fission protein dunamin-related protein 1 (Drp-1, in neuronal injury induced by oxygen-glucose deprivation (OGD in PC12 cells. We found that mdivi A and mdivi B inhibited OGD-induced neuronal injury through attenuating apoptotic cell death. These two inhibitors also preserved mitochondrial function, as evidenced by reduced reactive oxygen species (ROS generation and cytochrome c release, as well as prevented loss of mitochondrial membrane potential (MMP. Moreover, mdivi A and mdivi B significantly suppressed mitochondrial Ca2+ uptake, but had no effect on cytoplasmic Ca2+ after OGD injury. The results of calcium imaging and immunofluorescence staining showed that Drp-1 inhibitors attenuated endoplasmic reticulum (ER Ca2+ release and prevented ER morphological changes induced by OGD. These results demonstrate that Drp-1 inhibitors protect against ischemic neuronal injury through inhibiting mitochondrial Ca2+ uptake from the ER store and attenuating mitochondrial dysfunction.

Effects of sirolimus alone or in combination with cyclosporine A on renal ischemia/reperfusion injury

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B.J. Pereira

2010-08-01

Full Text Available Calcineurin inhibitors exacerbate ischemic injury in transplanted kidneys, but it is not known if sirolimus protects or exacerbates the transplanted kidney from ischemic injury. We determined the effects of sirolimus alone or in combination with cyclosporin A (CsA on oxygenated and hypoxic/reoxygenated rat proximal tubules in the following in vitro groups containing 6-9 rats per group: sirolimus (10, 50, 100, 250, 500, and 1000 ηg/mL; CsA (100 µg/mL; sirolimus (50 and 250 ηg/mL + CsA (100 µg/mL; control; vehicle (20% ethanol. For in vivo studies, 3-week-old Wistar rats (150-250 g were submitted to left nephrectomy and 30-min renal artery clamping. Renal function and histological evaluation were performed 24 h and 7 days after ischemia (I in five groups: sham, I, I + SRL (3 mg·kg-1·day-1, po, I + CsA (3 mg·kg-1·day-1, sc, I + SRL + CsA. Sirolimus did not injure oxygenated or hypoxic/reoxygenated proximal tubules and did not potentiate the tubular toxic effects of CsA. Neither drug affected the glomerular filtration rate (GFR at 24 h. GFR was reduced in CsA-treated rats on day 7 (0.5 ± 0.1 mL/min but not in rats receiving sirolimus + CsA (0.8 ± 0.1 mL/min despite the reduction in renal blood flow (3.9 ± 0.5 mL/min. Acute tubular necrosis regeneration was similar for all groups. Sirolimus alone was not toxic and did not enhance hypoxia/reoxygenation injury or CsA toxicity to proximal tubules. Despite its hemodynamic effects, sirolimus protected post-ischemic kidneys against CsA toxicity.

Phenolic indeno[1,2-b]indoles as ABCG2-selective potent and non-toxic inhibitors stimulating basal ATPase activity

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Gozzi GJ

2015-07-01

Full Text Available Gustavo Jabor Gozzi,1,2 Zouhair Bouaziz,3 Evelyn Winter,1,4 Nathalia Daflon-Yunes,1 Mylène Honorat,1 Nathalie Guragossian,3 Christelle Marminon,3 Glaucio Valdameri,1,2 Andre Bollacke,5 Jean Guillon,6 Noël Pinaud,7 Mathieu Marchivie,8 Silvia M Cadena,2 Joachim Jose,5 Marc Le Borgne,3 Attilio Di Pietro11Equipe Labellisée Ligue 2014, BMSSI UMR5086 CNRS/Lyon I University, IBCP, Lyon, France; 2Department of Biochemistry and Molecular Biology, Federal University of Paraná, Curitiba, Paraná, Brazil; 3Faculty of Pharmacy – ISPB, EA 4446 Biomolecules, Cancer and Chemoresistance, Health SFR of East Lyon CNRS UMS3453 - INSERM US7, University of Lyon, Lyon I University, Lyon Cedex 8, France; 4Department of Pharmaceutical Sciences, PGFAR, Federal University of Santa Catarina, Florianopolis, Santa Catarina, Brazil; 5Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Münster, Germany; 6ARNA Laboratory, Pharmaceutical Sciences UFR, INSERM U869, University of Bordeaux, Bordeaux Cedex, France; 7ISM – CNRS UMR 5255, University of Bordeaux Cedex, France; 8ICMCB CNRS-UPR 9048, University of Bordeaux, Pessac Cedex, FranceAbstract: Ketonic indeno[1,2-b]indole-9,10-dione derivatives, initially designed as human casein kinase II (CK2 inhibitors, were recently shown to be converted into efficient inhibitors of drug efflux by the breast cancer resistance protein ABCG2 upon suited substitutions including a N5-phenethyl on C-ring and hydrophobic groups on D-ring. A series of ten phenolic and seven p-quinonic derivatives were synthesized and screened for inhibition of both CK2 and ABCG2 activities. The best phenolic inhibitors were about threefold more potent against ABCG2 than the corresponding ketonic derivatives, and showed low cytotoxicity. They were selective for ABCG2 over both P-glycoprotein and MRP1 (multidrug resistance protein 1, whereas the ketonic derivatives also interacted with MRP1, and they additionally displayed a lower

Exploration of natural product ingredients as inhibitors of human HMG-CoA reductase through structure-based virtual screening.

Science.gov (United States)

Lin, Shih-Hung; Huang, Kao-Jean; Weng, Ching-Feng; Shiuan, David

2015-01-01

Cholesterol plays an important role in living cells. However, a very high level of cholesterol may lead to atherosclerosis. HMG-CoA (3-hydroxy-3-methylglutaryl coenzyme A) reductase is the key enzyme in the cholesterol biosynthesis pathway, and the statin-like drugs are inhibitors of human HMG-CoA reductase (hHMGR). The present study aimed to virtually screen for potential hHMGR inhibitors from natural product to discover hypolipidemic drug candidates with fewer side effects and lesser toxicities. We used the 3D structure 1HWK from the PDB (Protein Data Bank) database of hHMGR as the target to screen for the strongly bound compounds from the traditional Chinese medicine database. Many interesting molecules including polyphenolic compounds, polisubstituted heterocyclics, and linear lipophilic alcohols were identified and their ADMET (absorption, disrtibution, metabolism, excretion, toxicity) properties were predicted. Finally, four compounds were obtained for the in vitro validation experiments. The results indicated that curcumin and salvianolic acid C can effectively inhibit hHMGR, with IC50 (half maximal inhibitory concentration) values of 4.3 µM and 8 µM, respectively. The present study also demonstrated the feasibility of discovering new drug candidates through structure-based virtual screening.

Human skeletal muscle drug transporters determine local exposure and toxicity of statins.

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Knauer, Michael J; Urquhart, Bradley L; Meyer zu Schwabedissen, Henriette E; Schwarz, Ute I; Lemke, Christopher J; Leake, Brenda F; Kim, Richard B; Tirona, Rommel G

2010-02-05

The 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, or statins, are important drugs used in the treatment and prevention of cardiovascular disease. Although statins are well tolerated, many patients develop myopathy manifesting as muscle aches and pain. Rhabdomyolysis is a rare but severe toxicity of statins. Interindividual differences in the activities of hepatic membrane drug transporters and metabolic enzymes are known to influence statin plasma pharmacokinetics and risk for myopathy. Interestingly, little is known regarding the molecular determinants of statin distribution into skeletal muscle and its relevance to toxicity. We sought to identify statin transporters in human skeletal muscle and determine their impact on statin toxicity in vitro. We demonstrate that the uptake transporter OATP2B1 (human organic anion transporting polypeptide 2B1) and the efflux transporters, multidrug resistance-associated protein (MRP)1, MRP4, and MRP5 are expressed on the sarcolemmal membrane of human skeletal muscle fibers and that atorvastatin and rosuvastatin are substrates of these transporters when assessed using a heterologous expression system. In an in vitro model of differentiated, primary human skeletal muscle myoblast cells, we demonstrate basal membrane expression and drug efflux activity of MRP1, which contributes to reducing intracellular statin accumulation. Furthermore, we show that expression of human OATP2B1 in human skeletal muscle myoblast cells by adenoviral vectors increases intracellular accumulation and toxicity of statins and such effects were abrogated when cells overexpressed MRP1. These results identify key membrane transporters as modulators of skeletal muscle statin exposure and toxicity.

Activity of dual SRC-ABL inhibitors highlights the role of BCR/ABL kinase dynamics in drug resistance

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Azam, Mohammad; Nardi, Valentina; Shakespeare, William C.; Metcalf, Chester A.; Bohacek, Regine S.; Wang, Yihan; Sundaramoorthi, Raji; Sliz, Piotr; Veach, Darren R.; Bornmann, William G.; Clarkson, Bayard; Dalgarno, David C.; Sawyer, Tomi K.; Daley, George Q.

2006-01-01

Mutation in the ABL kinase domain is the principal mechanism of imatinib resistance in patients with chronic myelogenous leukemia. Many mutations favor active kinase conformations that preclude imatinib binding. Because the active forms of ABL and SRC resemble one another, we tested two dual SRC-ABL kinase inhibitors, AP23464 and PD166326, against 58 imatinib-resistant (IMR) BCR/ABL kinase variants. Both compounds potently inhibit most IMR variants, and in vitro drug selection demonstrates that active (AP23464) and open (PD166326) conformation-specific compounds are less susceptible to resistance than imatinib. Combinations of inhibitors suppressed essentially all resistance mutations, with the notable exception of T315I. Guided by mutagenesis studies and molecular modeling, we designed a series of AP23464 analogues to target T315I. The analogue AP23846 inhibited both native and T315I variants of BCR/ABL with submicromolar potency but showed nonspecific cellular toxicity. Our data illustrate how conformational dynamics of the ABL kinase accounts for the activity of dual SRC-ABL inhibitors against IMR-mutants and provides a rationale for combining conformation specific inhibitors to suppress resistance. PMID:16754879

Efficacy and safety of COX-2 inhibitors for advanced non-small-cell lung cancer with chemotherapy: a meta-analysis

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Dai P

2018-02-01

.18, progression-free survival (HR =0.97, 95% CI: 0.86–1.10, and 1-year survival rate (RR =1.03, 95% CI: 0.89–1.20. Toxicity did not differ significantly between COX-2 inhibitors plus chemotherapy and chemotherapy alone with the exception of leukopenia (RR =1.21, 95% CI: 1.03–1.42, thrombocytopenia (RR =1.32, 95% CI: 1.04–1.67, and cardiovascular events (RR =2.39, 95% CI: 1.06–5.42. The results of the Egger’s test indicated no significant difference in primary outcomes.Conclusion: COX-2 inhibitors improved ORR of advanced NSCLC with chemotherapy, but had no effect on survival indices. Moreover, COX-2 inhibitors may lead to higher rates of hematologic toxicities and cardiovascular events. Keywords: cyclooxygenase-2 inhibitors, non-small-cell lung cancer, chemotherapy, overall survival, meta-analysis 

The proteasome inhibitor bortezomib induces testicular toxicity by upregulation of oxidative stress, AMP-activated protein kinase (AMPK) activation and deregulation of germ cell development in adult murine testis

International Nuclear Information System (INIS)

Li, Wei; Fu, Jianfang; Zhang, Shun; Zhao, Jie; Xie, Nianlin; Cai, Guoqing

2015-01-01

Understanding how chemotherapeutic agents mediate testicular toxicity is crucial in light of compelling evidence that male infertility, one of the severe late side effects of intensive cancer treatment, occurs more often than they are expected to. Previous study demonstrated that bortezomib (BTZ), a 26S proteasome inhibitor used to treat refractory multiple myeloma (MM), exerts deleterious impacts on spermatogenesis in pubertal mice via unknown mechanisms. Here, we showed that intermittent treatment with BTZ resulted in fertility impairment in adult mice, evidenced by testicular atrophy, desquamation of immature germ cells and reduced caudal sperm storage. These deleterious effects may originate from the elevated apoptosis in distinct germ cells during the acute phase and the subsequent disruption of Sertoli–germ cell anchoring junctions (AJs) during the late recovery. Mechanistically, balance between AMP-activated protein kinase (AMPK) activation and Akt/ERK pathway appeared to be indispensable for AJ integrity during the late testicular recovery. Of particular interest, the upregulated testicular apoptosis and the following disturbance of Sertoli–germ cell interaction may both stem from the excessive oxidative stress elicited by BTZ exposure. We also provided the in vitro evidence that AMPK-dependent mechanisms counteract follicle-stimulating hormone (FSH) proliferative effects in BTZ-exposed Sertoli cells. Collectively, BTZ appeared to efficiently prevent germ cells from normal development via multiple mechanisms in adult mice. Employment of antioxidants and/or AMPK inhibitor may represent an attractive strategy of fertility preservation in male MM patients exposed to conventional BTZ therapy and warrants further investigation. - Highlights: • Intermittent treatment with BTZ caused fertility impairment in adult mice. • BTZ treatment elicited apoptosis during early phase of testicular recovery. • Up-regulation of oxidative stress by BTZ treatment

The proteasome inhibitor bortezomib induces testicular toxicity by upregulation of oxidative stress, AMP-activated protein kinase (AMPK) activation and deregulation of germ cell development in adult murine testis

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Li, Wei [Department of Human Anatomy, Histology and Embryology, Fourth Military Medical University, Xi' an 710032 (China); Fu, Jianfang [Department of Endocrinology, Xijing Hospital, Fourth Military Medical University, Xi' an 710032 (China); Zhang, Shun [Reproductive Medicine Center, Department of Gynecology and Obstetrics, Tangdu Hospital, Fourth Military Medical University, Xi' an 710038 (China); Zhao, Jie [Department of Human Anatomy, Histology and Embryology, Fourth Military Medical University, Xi' an 710032 (China); Xie, Nianlin, E-mail: xienianlin@126.com [Department of Thoracic Surgery, Tangdu Hospital, Fourth Military Medical University, Xi' an 710038 (China); Cai, Guoqing, E-mail: firstchair@fmmu.edu.cn [Department of Gynaecology and Obstetrics, Xijing Hospital, Fourth Military Medical University, Xi' an 710032 (China)

2015-06-01

Understanding how chemotherapeutic agents mediate testicular toxicity is crucial in light of compelling evidence that male infertility, one of the severe late side effects of intensive cancer treatment, occurs more often than they are expected to. Previous study demonstrated that bortezomib (BTZ), a 26S proteasome inhibitor used to treat refractory multiple myeloma (MM), exerts deleterious impacts on spermatogenesis in pubertal mice via unknown mechanisms. Here, we showed that intermittent treatment with BTZ resulted in fertility impairment in adult mice, evidenced by testicular atrophy, desquamation of immature germ cells and reduced caudal sperm storage. These deleterious effects may originate from the elevated apoptosis in distinct germ cells during the acute phase and the subsequent disruption of Sertoli–germ cell anchoring junctions (AJs) during the late recovery. Mechanistically, balance between AMP-activated protein kinase (AMPK) activation and Akt/ERK pathway appeared to be indispensable for AJ integrity during the late testicular recovery. Of particular interest, the upregulated testicular apoptosis and the following disturbance of Sertoli–germ cell interaction may both stem from the excessive oxidative stress elicited by BTZ exposure. We also provided the in vitro evidence that AMPK-dependent mechanisms counteract follicle-stimulating hormone (FSH) proliferative effects in BTZ-exposed Sertoli cells. Collectively, BTZ appeared to efficiently prevent germ cells from normal development via multiple mechanisms in adult mice. Employment of antioxidants and/or AMPK inhibitor may represent an attractive strategy of fertility preservation in male MM patients exposed to conventional BTZ therapy and warrants further investigation. - Highlights: • Intermittent treatment with BTZ caused fertility impairment in adult mice. • BTZ treatment elicited apoptosis during early phase of testicular recovery. • Up-regulation of oxidative stress by BTZ treatment

General amyloid inhibitors? A critical examination of the inhibition of IAPP amyloid formation by inositol stereoisomers.