Anti-apoptotic Role Research Articles

Cytokine-induced translocation of GRP78 to the plasma membrane triggers a pro-apoptotic feedback loop in pancreatic beta cells

The 78-kDa glucose-regulated protein (GRP78) is an ubiquitously expressed endoplasmic reticulum chaperone, with a central role in maintaining protein homeostasis. Recently, an alternative role for GRP78 under stress conditions has been proposed, with stress-induced extracellular secretion and translocation of GRP78 to the cell surface where it acts as a multifunctional signaling receptor. Here we demonstrate translocation of GRP78 to the surface of human EndoC-βH1 cells and primary human islets upon cytokine exposure, in analogy to observations in rodent INS-1E and MIN6 beta cell lines. We show that GRP78 is shuttled via the anterograde secretory pathway, through the Golgi complex and secretory granules, and identify the DNAJ homolog subfamily C member 3 (DNAJC3) as a GRP78-interacting protein that facilitates its membrane translocation. Evaluation of downstream signaling pathways, using N- and C-terminal anti-GRP78 blocking antibodies, demonstrates that both GRP78 signaling domains initiate pro-apoptotic signaling cascades in beta cells. Extracellular GRP78 itself is identified as a ligand for cell surface GRP78 (sGRP78), increasing caspase 3/7 activity and cell death upon binding, which is accompanied by enhanced Chop and Bax mRNA expression. These results suggest that inflammatory cytokines induce a self-destructive pro-apoptotic feedback loop through the secretion and membrane translocation of GRP78. This proapoptotic function distinguishes the role of sGRP78 in beta cells from its reported anti-apoptotic and proliferative role in cancer cells, opening the road for the use of compounds that block sGRP78 as potential beta cell-preserving therapies in type 1 diabetes.

HuR controls apoptosis and activation response without effects on cytokine 3’ UTRs

ABSTRACT RNA binding proteins regulate gene expression through several post-transcriptional mechanisms. The broadly expressed HuR/ELAVL1 is important for proper function of multiple immune cell types, and has been proposed to regulate cytokine and other mRNA 3′ UTRs upon activation. However, this mechanism has not been previously dissected in stable cellular settings. In this study, HuR demonstrated strong anti-apoptotic and activation roles in Jurkat T cells. Detailed transcriptomic analysis of HuR knockout cells revealed a substantial negative impact on the activation program, coordinately preventing the expression of immune response gene categories, including all cytokines. Knockout cells showed a significant defect in IL-2 production, which was rescued upon reintroduction of HuR. Interestingly, the mechanism of HuR regulation did not involve control of the cytokine 3′ UTRs: HuR knockout did not affect the activity of 3′ UTR reporters in 293 cells, and had no effect on IL-2 and TNF 3′ UTRs in resting or activated Jurkats. Instead, impaired cytokine production corresponded with defective induction of the IL-2 promoter upon activation. Accordingly, upregulation of NFATC1 was also impaired, without 3′ UTR effects. Together, these results indicate that HuR controls cytokine production through coordinated upstream pathways, and that additional mechanisms must be considered in investigating its function.

Type 3 inositol 1,4,5-trisphosphate receptor has antiapoptotic and proliferative role in cancer cells

Although the involvement of type 1 (IP3R1) and type 2 (IP3R2) inositol 1,4,5-trisphosphate receptors in apoptosis induction has been well documented in different cancer cells and tissues, the function of type 3 IP3R (IP3R3) is still elusive. Therefore, in this work we focused on the role of IP3R3 in tumor cells in vitro and in vivo. We determined increased expression of this receptor in clear cell renal cell carcinoma compared to matched unaffected part of the kidney from the same patient. Thus, we hypothesized about different functions of IP3R3 compared to IP3R1 and IP3R2 in tumor cells. Silencing of IP3R1 prevented apoptosis induction in colorectal cancer DLD1 cells, ovarian cancer A2780 cells, and clear cell renal cell carcinoma RCC4 cells, compared to apoptosis in cells treated with scrambled siRNA. As expected, silencing of IP3R3 and subsequent apoptosis induction resulted in increased levels of apoptosis in all these cells. Further, we prepared a DLD1/IP3R3_del cell line using CRISPR/Cas9 gene editing method. These cells were injected into nude mice and tumor's volume was compared with tumors induced by DLD1 cells. Lower volume of tumors originated from DLD1/IP3R3_del cells was observed after 12 days, compared to wild type DLD1 cells. Also, the migration of these cells was lesser compared to wild type DLD1 cells. Apoptosis under hypoxic conditions was more pronounced in DLD1/IP3R3_del cells than in DLD1 cells. These results clearly show that IP3R3 has proliferative and anti-apoptotic effect in tumor cells, on contrary to the pro-apoptotic effect of IP3R1.

Upregulation of miR-200a and miR-204 in MPP+ -treated differentiated PC12 cells as a model of Parkinson's disease.

BackgroundParkinson's disease (PD) is ranked as the second most common neurodegenerative disorder caused by loss of dopaminergic neurons in the substantia nigra. Micro(mi)RNAs are a class of small noncoding RNAs that regulate gene expression and aberrant expression of them is closely correlated with many neurodegenerative conditions including PD. Silent information regulator 1 (SIRT1) as a known deacetylase and B‐cell lymphoma‐2 (BCL2) as an antiapoptotic factor play vital roles in neural protection and survival.MethodsDifferentiated PC12 cells exposed to MPP+ were served here as a known PD model. Cell viability was determined by MTS assay. Apoptotic cells and ROS levels were detected using flow cytometry. Gene selection and miRNA–mRNA interaction analysis were performed through in silico methods. Relative expression of miRNAs and genes was examined by RT‐qPCR.ResultsMPP+ exposure markedly reduced cell viability, enhanced oxidative stress, and induced apoptosis in differentiated PC12 cells. Sirt1 and BCL2were shown to be markedly declined in response to MPP+, while miR‐200a and miR‐204 were significantly upregulated.ConclusionThe first novel finding of the current study is altered expression of miR‐200a and miR‐204 in differentiated PC12 cells in response to MPP+, suggesting that deregulation of them participate in MPP+ neurotoxicity mechanisms, possibly via affecting the expression of Sirt1 and BCL2 as potential targets.

Chemerin reverses neurological impairments and ameliorates neuronal apoptosis through ChemR23/CAMKK2/AMPK pathway in neonatal hypoxic\u2013ischemic encephalopathy

Hypoxic–ischemic encephalopathy (HIE) is a devastating neurological event that contributes to the prolonged neurodevelopmental consequences in infants. Therapeutic strategies focused on attenuating neuronal apoptosis in the penumbra appears to be promising. Given the increasingly recognized neuroprotective roles of adipokines in HIE, we investigated the potential anti-apoptotic roles of a novel member of adipokines, Chemerin, in an experimental model of HIE. In the present study, 10-day-old rat pups underwent right common carotid artery ligation followed by 2.5 h hypoxia. At 1 h post hypoxia, pups were intranasally administered with human recombinant chemerin (rh-chemerin). Here, we showed that rh-chemerin prevented the neuronal apoptosis and degeneration as evidenced by the decreased expression of the pro-apoptotic markers, cleaved caspase 3 and Bax, as well as the numbers of Fluoro-Jade C and TUNEL-positive neurons. Furthermore, rh-Chemerin reversed neurological and morphological impairments induced by hypoxia–ischemia in neonatal rats at 24 h and 4 weeks after HIE. In addition, chemerin-mediated neuronal survival correlated with the elevation of chemerin receptor 23 (chemR23), phosphorylated calmodulin-dependent protein kinase kinase 2 (CAMKK2), as well as phosphorylated adenosine monophosphate-activated protein kinase (AMPK). Specific inhibition of chemR23, CAMKK2, and AMPK abolished the anti-apoptotic effects of rh-chemerin at 24 h after HIE, demonstrating that rh-chemerin ameliorated neuronal apoptosis partially via activating chemR23/CAMKK2/AMPK signaling pathway. Neuronal apoptosis is a well-established contributing factor of pathological changes and the neurological impairment after HIE. These results revealed mechanisms of neuroprotection by rh-chemerin, and indicated that activation of chemR23 might be harnessed to protect from neuronal apoptosis in HIE.

Hepato-preventive and anti-apoptotic role of boric acid against liver injury induced by cyclophosphamide

This study aims to examine cyclophosphamide (CP) exsposure associated toxicity on rat livers and the likely defensive effects of boric acid (BA). The rats used in this study were divided into four groups: control group, CP group, BA group, and BA + CP group. The present study was carried out using routine histological H&E stain, immunohistochemical stain caspase-3 as apoptotic marker, serum biochemical analysis for liver function markers (alanine transaminase (ALT), aspartate transaminase (AST) and alkalen phosphatase (ALP)), oxidative stress markers (total oxidant status (TOS), oxidative stress index (OSI) and total antioxidant capacity marker (TAC)). In the CP group, the levels of ALT, AST, ALP, TOS, OSI and caspase-3 increased whereas TAC levels decreased compared with the control group. In the BA + CP group, the levels of ALT, AST, ALP, TOS, OSI and caspase-3 decreased whereas TAC levels increased compared with the CP group. The histopathological evaluation of light microscope images and immunohistochemical caspase-3 activity in the BA + CP group were found to be decrease compared with those in the CP group. In conclusion, BA was successful in defending the liver against apoptosis and histopathological changes that are attributable to CP.

Administration of rCTRP9 Attenuates Neuronal Apoptosis Through AdipoR1/PI3K/Akt Signaling Pathway after ICH in Mice

Targeting neuronal apoptosis after intracerebral hemorrhage (ICH) may be an important therapeutic strategy for ICH patients. Emerging evidence indicates that C1q/TNF-Related Protein 9 (CTRP9), a newly discovered adiponectin receptor agonist, exerts neuroprotection in cerebrovascular disease. The aim of this study was to investigate the anti-apoptotic role of CTRP9 after experimental ICH and to explore the underlying molecular mechanisms. ICH was induced in mice via intrastriatal injection of bacterial collagenase. Recombinant CTRP9 (rCTRP9) was administrated intranasally at 1 h after ICH. To elucidate the underlying mechanisms, adiponectin receptor1 small interfering ribonucleic acid (AdipoR1 siRNA) and selective PI3 K inhibitor LY294002 were administered prior to rCTRP9 treatment. Western blots, neurofunctional assessments, immunofluorescence staining, and Fluoro-Jade C (FJC) staining experiments were performed. Administration of rCTRP9 significantly improved both short- and long-term neurofunctional behavior after ICH. RCTRP9 treatment significantly increased the expression of AdipoR1, PI3 K, p-Akt, and Bcl-2, while at the same time was found to decrease the expression of Bax in the brain, which was reversed by inhibition of AdipoR1 and PI3 K. The neuroprotective effect of rCTRP9 after ICH was mediated by attenuation of neuronal apoptosis via the AdipoR1/PI3K/Akt signaling pathway; therefore, rCTRP9 should be further evaluated as a potential therapeutic agent for ICH patients.

NLRP7 is increased in human idiopathic fetal growth restriction and plays a critical role in trophoblast differentiation.

Fetal growth restriction (FGR) the leading cause of perinatal mortality and morbidity is highly related to abnormal placental development, and placentas from FGR pregnancies are often characterized by increased inflammation. However, the mechanisms of FGR-associated inflammation are far from being understood. NLRP7, a member of a family of receptors involved in the innate immune responses, has been shown to be associated with gestational trophoblastic diseases. Here, we characterized the expression and the functional role of NLRP7 in the placenta and investigated its involvement in the pathogenesis of FGR. We used primary trophoblasts and placental explants that were collected during early pregnancy, and established trophoblast-derived cell lines, human placental villi, and serum samples from early pregnancy (n = 38) and from FGR (n = 40) and age-matched controls (n = 32). Our results show that NLRP7 (i) is predominantly expressed in the trophoblasts during the hypoxic period of placental development and its expression is upregulated by hypoxia and (ii) increases trophoblast proliferation ([3H]-thymidine) and controls the precocious differentiation of trophoblasts towards syncytium (syncytin 1 and 2 and β-hCG production and xCELLigence analysis) and towards invasive extravillous trophoblast (2D and 3D cultures). We have also demonstrated that NLRP7 inflammasome activation in trophoblast cells increases IL-1β, but not IL-18 secretion. In relation to the FGR, we demonstrated that major components of NLRP7 inflammasome machinery are increased and that IL-1β but not IL-18 circulating levels are increased in FGR. Altogether, our results identified NLRP7 as a critical placental factor and provided evidence for its deregulation in FGR. NLRP7 inflammasome is abundantly expressed by trophoblast cells. It is regulated by a key parameter of placental development, hypoxia. It controls trophoblast proliferation, migration, and invasion and exhibits anti-apoptotic role. NLRP7 machinery is deregulated in FGR pregnancies. KEY MESSAGES: NLRP7 inflammasome is abundantly expressed by trophoblast cells. It is regulated by a key parameter of placental development, hypoxia. It controls trophoblast proliferation, migration, and invasion and exhibits anti-apoptotic role. NLRP7 machinery is deregulated in FGR pregnancies.

Human menstrual blood-derived stem cells protect H9c2 cells against hydrogen peroxide-associated apoptosis.

Human menstrual blood-derived mesenchymal stem cells (MenSCs) hold great promise for regenerative medicine. Here, H2O2-associated damage in H9c2 cells was employed as an in vitro ischemia-reperfusion model, and the transwell system was used to explore the beneficial effects of MenSCs on the H2O2-induced damage of myocardial H9c2 cells. H2O2 treatment resulted in decreased viability and migration rate, with increased apoptosis levels in cells. By contrast, upon co-culture with MenSCs, H9c2 cell viability and migration were increased, whereas the apoptotic rate decreased. Additionally, western blot and qRT-PCR showed that MenSCs mediated the anti-apoptotic role by downregulating the pro-apoptotic genes Bax and caspase-3, while upregulating the anti-apoptotic effector Bcl-2. Furthermore, co-culture with MenSCs resulted in elevated expression of N-cadherin after H2O2 treatment. These findings indicate that MenSCs protect H9c2 cells against H2O2-associated programmed cell death and would help develop therapeutic tools for cardiomyocyte apoptosis associated with oxidative stress.

Methylation of the first exon in the erythropoietin receptor gene does not correlate with its mRNA and protein level in cancer cells

BackgroundErythropoietin receptor (EPOR) is a functional membrane-bound cytokine receptor. Erythropoietin (EPO) represents an important hematopoietic factor for production, maturation and differentiation of erythroid progenitors. In non-hematopoietic tissue, EPO/EPOR signalization could also play cytoprotective and anti-apoptotic role. Several studies identified pro-stimulating EPO/EPOR effects in tumor cells; however, numerous studies opposed this fact due to the usage of unspecific EPOR antibodies and thus potential absence or very low levels of EPOR in tumor cells. It seems that this problem is more complex and therefore we have decided to focus on EPOR expression at several levels such as the role of methylation in the regulation of EPOR expression, identification of possible EPOR transcripts and the presence of EPOR protein in selected tumor cells.MethodsMethylation status was analysed by bisulfite conversion reaction, PCR and sequencing. The expression of EPOR was monitored by quantitative RT-PCR and western blot analysis.ResultsIn this study we investigated the methylation status of exon 1 of EPOR gene in selected human cancer cell lines. Our results indicated that CpGs methylation in exon 1 do not play a significant role in the regulation of EPOR transcription. However, methylation status of EPOR exon 1 was cell type dependent. We also observed the existence of two EPOR splice variants in human ovarian adenocarcinoma cell line - A2780 and confirmed the expression of EPOR protein in these cells using specific A82 anti-EPOR antibody.ConclusionWe outlined the methylation status of all selected cancer cell lines in exon 1 of EPOR gene and these results could benefit future investigations. Moreover, A82 antibody confirmed our previous results demonstrating the presence of functional EPOR in human ovarian adenocarcinoma A2780 cells.

New insights into the immunomodulatory role of exosomes in cardiovascular disease

Exosomes, nanosized lipid bilayer membranous vesicles, are secreted by a variety of cells and contain protein, lipids, mRNA, miRNA, and signaling molecules that participate in intercellular material transfer and information exchange through binding, fusion or endocytosis. Exosomes mediate the gene expression of target cells and regulate pathological and physiological processes, thereby playing a key role in the occurrence and development of various diseases. Accumulated studies has shown that exosomes hold therapeutic potential though their anti-apoptotic and anti-fibrotic roles. They also have been shown to promote angiogenesis, inhibit ventricular remodeling and improve cardiac function, as well as inhibiting local inflammation and regulating the immune response. As such, exosomes represent a new target for the treatment of cardiovascular diseases. This review summarizes the literature in this field to date, including the basic biological characteristics of exosomes, and new progress in the understanding of the mechanisms of their involvement in immune regulation in cardiovascular diseases. In this way, it servrs as a basis for future research and the development of therapeutic exosomes.

Qingxin kaiqiao fang ameliorates memory impairment and inhibits apoptosis in APP/PS1 double transgenic mice through the MAPK pathway.

BackgroundQingxin kaiqiao fang (QKF) has been found to treat Alzheimer’s disease (AD) through apoptosis inhibition. The mitogen-activated protein kinase (MAPK) pathway is closely related to apoptosis in the course of AD. This study aimed to investigate whether QKF-induced apoptosis depression is achieved through MAPK pathway.Materials and methodsC57BL/6 J and APP/PS1 mice were used as control and model groups. APP/PS1 mice were treated with different dosages of QKF (4.75, 9.5, and 19 g⋅kg−1⋅d−1⋅ig, respectively) for 12 weeks as L-QKF, M-QKF, and H-QKF groups. The M-QKF-treated APP/ PS1 mice were administrated with 2 µg/kg of U46619 and saline, intra ventricular ventricle injection, as M-QKF+U46619 and M-QKF+saline groups and were injected with PD98059 0.3 mg/kg and the same volume of dimethyl sulfoxide (DMSO), intravenous, as M-QKF+PD98059 and M-QKF+DMSO groups. After 12 weeks treatment, Morris water maze was performed for behavior study. Pathological degeneration was examined by H&E staining, Nissl staining, and transmission electron microscope observation of hippocampus; immunohistochemistry and Western blot (WB) were tested for amyloid β (Aβ) expression. Apoptosis was measured through TUNEL assay; Bax, Bcl-2, and caspase-3 expression through WB; and cleaved caspase-3 expression through ELISA. MAPK pathway was detected via WB for the expressions of ERK1/2, JNK, and p38 MAPK and their phosphorylation patterns.ResultsQKF improved the learning and memory capability, as well as inhibited neuronal apoptosis and then reduced the pathological degeneration of APP/PS1 mice. M-QKF reduced neuron apoptosis by inhibiting p38 MAPK and activating ERK1/2 but had no significant effect on JNK.ConclusionQKF, especially at the middle dose, alleviated the learning and memory impairment and played an antiapoptotic role in AD through MAPK pathways.

Antiapoptotic role of Agaricus blazei extract in rodent model of Parkinson's disease.

Rotenoneis a pesticide that has been shown to induce the pathological symptoms ofParkinson'sdisease(PD) in both cellular and animal models. In this study, we investigated the protective effect of Agaricus blazei extract onrotenone-induceddopaminergic degeneration and apoptosisin mice model. A. blazei extract blocked therotenone-mediated diminution of dopamine transporter (DAT) and vesicular monoamine transporter 2 (VMAT 2) expression and the downregulation of Bcl-2 and the upregulation of Bax, caspases-3, -6, -8 and caspase-9. Present data suggest that A. blazei extract plays a crucial role in regulation of proteins expression such as DAT and VMAT2 and pro-apoptotic and anti-apoptotic in Parkinsonism. In conclusion, the present study shows that A. blazei extract act as potential neuroprotective agent in the management of Parkinsonism.

The Anti-inflammatory and Anti-apoptotic Role of Crocin against Expression of MMp-9, TIMP-1, MCP-1, Caspase-3, PPARα in Heart Tissue, and Metamorphoses of MicroRNA 188 in Hyperhomocysteinemic Rats

Crocin (a water-soluble carotenoid) is the most abundant antioxidant among active constituents of Crocus sativus. Crocin has protective effects on brain, skeletal muscle, and kidney ischemia-reperfusion injury models via its antioxidant properties. The protective and anti-inflammatory effect of crocin against L-methionine-induced hyperhomocysteinemia (HHcy) in rats was evaluated. Thirty male albino rats were divided into three equal groups. Group I (control normal): rats fed ordinary diet without any treatment. Group II (L-methionine-induced HHcy): rats received L-methionine (1.7 g/kg body weight/day) orally for 8 weeks continuously. Group III (HHcy 1 crocin): rats received crocin in dose (50 mg/kg body weight/day, I.P.) for 4 weeks after induction of HHcy. The results obtained showed a significant increase in serum Hcy concentration and upregulation of NF-kβ gene expression in liver tissue and also in the gene expression level of TIMP-1, MMp-9, MCP-1, Caspase-3, and PPARα in heart tissues with significant downregulation of serum miRNA188 gene expression level in hyperhomocysteinemic (HHcy) rats. However, crocin treatment to HHcy induced in rats significantly improved all previous indicators to its normal ranges. The histopathological findings revealed that crocin treatment markedly reduced the HHcy-induced pathological changes and displayed marked improvement with normal histological architecture of the heart and brain tissues. These results suggested that crocin had a potentially ameliorating role with powerful anti-inflammatory and anti-apoptotic effects on cardiac tissue, as revealed by suppression of proinflammatory mediators and secretion through inhibition of NF-kB signaling pathways, which may lead to upregulated miR-188 gene expression, suppress proapoptotic Caspase-3, and may protect from heart tissue injury against HHcy.

Inhibition of Connexin43 hemichannels with Gap19 protects cerebral ischemia/reperfusion injury via the JAK2/STAT3 pathway in mice

Functional disruption of the neurovascular unit may lead to aggravation of ischemic cerebral injury. Connexin43 (Cx43)-dependent gap junctional channels (GJCs) are critical in maintaining brain homeostasis. However, excessive opening of hemichannels (HCs) after cerebral ischemia may cause apoptosis and finally lead to amplification of ischemic injury. Previous studies indicated that Cx43 mimetic peptides Gap26 and Gap27 may protect cerebral ischemic injury, but the latest studies showed they also inhibit the opening of GJCs, which are beneficial for neuroprotection. Recent studies showed that Gap19 is a new specific inhibitor of Cx43 HCs. We investigated the role of Gap19 on cerebral ischemia/reperfusion (I/R) injury in a mouse model of middle cerebral artery occlusion (MCAO). Ventricle-injected Gap19 significantly alleviated infarct volume, neuronal cell damage and neurological deficits after ischemia, the neuroprotective effect of Gap19 was significant stronger than Gap26. Post-treatment with TAT-Gap19 still provided neuroprotection when it was administered intraperitoneally at 4 h after reperfusion. In addition, we found that Gap19 decreased the levels of cleaved caspase-3 and Bax and increased the level of Bcl-2, suggesting the anti-apoptotic activity of specifically blocking the Cx43 HCs. Furthermore, our data indicate that Gap19 treatment increased the levels of phosphorylated JAK2 and STAT3 both in vivo and in vitro. Gap19 inhibited hemichannel activity assessed by dye uptake in astrocytes. And we detected that pSTAT3 co-localized with Cx43 together in astrocytes after oxygen glucose deprivation (OGD) injury. Finally, AG490, a blocker of the JAK2/STAT3 pathway, could reverse the neuroprotective effects of Gap19 both in vivo and in vitro. Our experiment investigated the anti-apoptotic activity of Gap19, the specific inhibitor of Cx43 HCs, and the potential mechanisms. Our results demonstrated that Gap19 plays an anti-apoptotic role via activating the JAK2/STAT3 pathway after cerebral I/R injury, indicating that specific blocking of Cx43 HCs is a potential target for ischemic stroke.

Dietary pomegranate supplement alleviates murine pancreatitis by modulating Nrf2-p21 interaction and controlling apoptosis to survival switch

Dietary supplementation of polyphenol-rich pomegranate extract (POMx) has been shown to have anti-oxidant and anti-inflammatory activities. Here, we evaluate the efficacy of POMx in mitigating pancreatitis in mice and provide a mechanistic outline of the process. Age-matched male Swiss albino mice were injected with Lipopolysaccharide (LPS) and given POMx supplement alone or in combination with LPS. After 4 weeks of treatment histological scoring for pancreatic edema and vacuolization was performed. Serum insulin levels were estimated and the glucose tolerance test (IPGTT) data revealed that POMx reduced inflammation induced hyperglycemia in mice. Analysis of TLR4, IκB expression, and NF-κB nuclear translocation, and concentrations of IL-6 and TNFα showed that POMx is able to modulate the molecular instigators of inflammatory responses. Annexin V assay indicated that POMx protects against inflammation-mediated apoptosis in the pancreas. Expression profile of SAPK/JNK pathway, p53, Bax, Bcl-2 and Caspase-3 validate an apoptotic to survival shift in POMx treatment group. Co-immunoprecipitation studies show that POMx stabilizes p21 and Nrf2 interaction and increases its nuclear translocation. The study also proves that the nuclear fraction of Nrf2 is able to bind to the Bcl-2 promoter and activate an anti-apoptotic program. The findings of our study underline an anti-inflammatory, anti-oxidative and anti-apoptotic role of POMx and provide a mechanistic idea of how POMx confers protection during pancreatitis.

L-arginine inhibited apoptosis of fish leukocytes via regulation of NF-κB-mediated inflammation, NO synthesis, and anti-oxidant capacity

The increased apoptosis plays an important role in bacterial invasion. In addition, LPS can induce inflammation and apoptosis of leukocytes via the production of reactive oxygen and nitrogen species. In the present study, we investigated the potential protective role of l-arginine (L-Arg) against the apoptosis of fish leukocytes in vitro. The results of Annexin V-FITC/PI staining and TUNEL assay indicated that L-Arg significantly alleviated the apoptosis of fish leukocytes induced by LPS at 24 h and 72 h post incubation (hpi). High caspase-3 activities induced by LPS at 72 hpi were significantly inhibited by L-Arg. Moreover, L-Arg supplementation also significantly decreased the mRNA expression levels of caspases at most time points, which contributed to the anti-apoptotic roles of L-Arg. Further analysis showed that L-Arg significantly inhibited the expression of several pro-inflammatory cytokines including IL-8 and TNF-α, partially via the down-regulation of the genes involved in NF-κB/MyD88 including NF-κB, IKKα and IKKγ. The down-regulation of these pro-inflammatory cytokines by L-Arg supplementation led to the further decrease in the expression of death receptor FasL, contributing to the anti-apoptotic effect of L-Arg. In addition, L-Arg supplementation increased both iNOS mRNA expression and NO production. The mRNA expressions of several anti-oxidant enzymes including SOD, CAT and GSHPx were also significantly increased after L-Arg supplementation, which accelerated the clearance of reactive oxygen species. In all, L-Arg inhibited apoptosis of fish leukocytes both via the increased NO production and antioxidant capacity and via the inhibition of inflammation mediated by NF-κB/MyD88 pathway.

NF1 regulates apoptosis in ovarian cancer cells by targeting MCL1 via miR-142-5p.

NF1 loss confers chemoresistance in multiple cancers. However, the etiology remains largely unknown. Our study aimed to scrutinize the role of NF1 in chemoresistant ovarian cancer and its underlying mechanism. 4',6-diamidino-2-phenylindole staining, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay, luciferase reporter assay, chromatin immunoprecipitation, Western blot, quantitative real-time-PCR and rescue experiments were performed to illustrate the antiapoptotic role of NF1 loss and its underlying mechanism. NF1-knockdown ovarian cells showed resistance to cisplatin-induced apoptosis. Furthermore, NF1 regulated MCL1 expression at protein level. Further dissections suggested that miR-142-5p was regulated by NF1 via its promoter and targeted MCL1. Consistently, miR-142-5p mimic and si-MCL1 can attenuate the antiapoptotic effect of NF1 knockdown. NF1 knockdown endowed ovarian cells with resistance to cisplatin-induced apoptosis by targeting MCL1 via miR-142-5p.

A study of CBS gene polymorphism, plasma H2S levels and their association in type-2 diabetes mellitus

Background: Hydrogen Sulphide (H2S), in recent years, is getting significant attention, as more evidences are emerging about its diverse biological roles. There are evidences of H2S having anti-inflammatory, neuro-modulator, vasodilator, anti-apoptotic and mitochondrial protective roles in various tissues. Among different tissues, β-cells of pancreas, according to some recent studies, get significantly affected by the imbalance in H2S homeostasis, leading to β-cell dysfunction and Diabetes Mellitus (DM). Cystathionine- β-synthase (CBS) enzyme is involved in the synthesis of H2S from cysteine in various tissues. Among various possible mutations in the CBS gene, a particular 833T-C mutation, has been found to be associated with various diseases.
 Aims and Objectives: The present study was aimed to determine the extent of abnormality of H2S homeostasis in type-2 DM patients, and to find out presence and association (if any) of 833T-C mutation in CBS gene, in the patients of type-2 DM, in comparison to healthy control subjects, in the Indian population.
 Materials and Methods: A cross sectional study was done with 40 clinically and biochemically diagnosed DM type II patients attending OPD of Endocrinology department of NRS Medical College & Hospital, Kolkata, and 40 age and gender matched non-diabetic control subjects. DNA was isolated from EDTA blood of all the study subjects, PCR done and results compared. Plasma H2S was measured by the N,N-dimethyl-p-phenylene-diamine method. Plasma glucose and serum insulin were measured by standardized commercial kits.
 Results: Our study found the plasma H2S levels in the patients of type II DM to be significantly higher(P<0.001) than the control subjects. The results also found significant positive correlation between plasma H2S level with fasting serum Insulin level (P<0.001) and fasting plasma glucose level (P<0.001) in the diabetic patients. Among 40 DM patients, only two were heterozygous for the mutation, and had both mutated allele (242bp) and normal allele (174bp). Rest of the patients and all the control subjects were homozygous for the normal allele (174bp). This marginal difference in the incidence of mutated allele was not found to be statistically significant.
 Conclusion: our study shows significant association of H2S dys-regulation with the type-2 Diabetes Mellitus in Indian population. The marginal but insignificantly higher incidence of 833T-C mutation in CBS gene, found in our study, warrants further research with higher number of study population, to more conclusively infer about the role of this mutation in the pathogenesis of type-2 DM.

Rosiglitazone up-regulates glial fibrillary acidic protein via HB-EGF secreted from astrocytes and neurons through PPARγ pathway and reduces apoptosis in high-fat diet-fed mice.

The anti-diabetic drug and peroxisome proliferator-activated receptor-gamma (PPARγ) agonist, rosiglitazone, alters astrocyte activation; however, its mechanism remains less-known. We hypothesized participation of epidermal growth factor receptor (EGFR), known to control astrocyte reactivity. We first detected that rosiglitazone promoted glial fibrillary acidic protein (GFAP) expression in primary astrocytes as well as the mouse cerebral cortex, associated with increased EGFR activation. Screening for EGFR ligands revealed a rosiglitazone-mediated increase of heparin-binding epidermal growth factor (HB-EGF) in astrocytes, resulting in HB-EGF release into culture medium and mouse cerebrospinal fluid too. Treatment with HB-EGF-siRNA and EGFR inhibitors showed that the rosiglitazone-induced HB-EGF and p-EFGR were interdependent, which participated in GFAP increase. Interestingly, we observed that rosiglitazone could induce cellular and secreted-HB-EGF in neurons also, contributing toward the activated EGFR-induced GFAP in astrocytes. Probing whether these effects of rosiglitazone were PPARγ-linked, revealed potential PPARγ-responsive elements within HB-EGF gene. Moreover, gel-shift, site-directed mutagenesis, chromatin-immunoprecipitation and luciferase-reporter assays demonstrated a PPARγ-dependent HB-EGF transactivation. Subsequently, we examined effects of rosiglitazone in a high-fat diet-fed diabetes mouse model, and supporting observations in the normal cortical cells, identified a rosiglitazone-induced GFAP, astrocyte and neuronal HB-EGF and secreted-HB-EGF in the cerebral cortex of diabetic mice. Moreover, assessing relevance of increased HB-EGF and GFAP revealed an anti-apoptotic role of rosiglitazone in the cerebral cortex, supported by a GFAP-siRNA as well as HB-EGF-siRNA-mediated increase in cleaved-caspase 3 and 9 levels in the rosiglitazone-treated astrocyte-neuron coculture. Overall, our study indicates that rosiglitazone may protect the brain, via a PPARγ-dependent HB-EGF/EGFR signaling and increased GFAP.