Ulcerative colitis(UC)is an idiopathic,relapsing,and etiologically complicated chronic inflammatory bowel disease.Despite substantial progress in the management of UC,the outcomes of mucosal barrier repair are unsatis...Ulcerative colitis(UC)is an idiopathic,relapsing,and etiologically complicated chronic inflammatory bowel disease.Despite substantial progress in the management of UC,the outcomes of mucosal barrier repair are unsatisfactory.In this study,phillygenin(PHI)treatment alleviated the symptoms of chronic colitis in mice,including body weight loss,severe disease activity index scores,colon shortening,splenomegaly,oxidative stress,and inflammatory response.In particular,PHI treatment ameliorated the tight junction proteins(TJs)reduction,fibrosis,apoptosis,and intestinal stem cell activity,indicating that PHI exerted beneficial effects on the intestinal mucosal barrier in mice with chronic colitis.In the NCM460 cells damage model,dextran sulfate sodium triggered the sequential induction of TJs reduction,fibrosis,and apoptosis.Takeda G protein-coupled receptor-5(TGR5)dysfunction mediated NCM460 cell injury.Moreover,PHI treatment enhanced TJs and suppressed fibrosis and apoptosis to maintain NCM460 cell function,depending on TGR5 activation.PHI promoted TGR5 activation and elevated intracellular cyclic adenosine monophosphate levels in HEK 293T cells transfected with TGR5 expression plasmids.Cellular thermal shift assay and molecular docking studies confirmed that PHI directly binds to TGR5,indicating that PHI is an agonist of TGR5.The process of PERK-eIF2α pathway-mediated endoplasmic reticulum Ca^(2+) release was involved in NCM460 cell injury as well,which was associated with TGR5 dysfunction.When NCM460 cells were pretreated with PHI,the PERK-eIF2α pathway and elevated Ca^(2+) levels were blocked.In conclusion,our study demonstrated a novel mechanism that PHI inhibited the PERK-eIF2α-Ca^(2+) pathway through TGR5 activation to against DSS-induced TJs reduction,fibrosis,and apoptosis.展开更多
5-Hydroxymethylfurfural （5-HMF）, a water-soluble compound extracted from wine-processed Fructus corni, is a novel hepatic protectant for treating acute liver injury. The present study was designed to investigate the...5-Hydroxymethylfurfural （5-HMF）, a water-soluble compound extracted from wine-processed Fructus corni, is a novel hepatic protectant for treating acute liver injury. The present study was designed to investigate the protective effect of 5-HMF in human L02 hepatocytes injured by D-galactosamine （GAIN） and tumor necrosis factor-α （TNF-α） in vitro and to explore the underlying mechanisms of action. Our results showed that 5-HMF caused significant increase in the viability of L02 cells injured by GalN/TNF-α, in accordance with a dose-dependent decrease in apoptotic cell death confirmed by morphological and flow cytometric analyses. Based on immunofluorescence and Western blot assays, we found that GalN/TNF-α induced ER stress in the cells, as indicated by the disturbance of intracellular Ca^2＋ concentration, the activation of protein kinase RNA （PKR）-like ER kinase （PERK）, phosphorylation of eukaryotic initiation factor 2 alpha （eIF2α）, and expression of ATF4 and CHOP proteins, which was reversed by 5-HMF pre-treatment in a dose-dependent manner. The anti-apoptotic effect of 5-HMF was further evidenced by balancing the expression of Bcl-2 family members. In addition, the knockdown of PERK suppressed the expression of phospho-PERK, phospho-eIF2α, ATF4, and CHOP, resulting in a significant decrease in cell apoptosis after the treatment with GalN/TNF-α. 5-HMF could enhance the effects of PERK knockdown, protecting the cells against the GalN/TNF-α insult. In conclusion, these findings demonstrate that 5-HMF can effectively protect GalN/TNF-α-injured L02 hepatocytes against ER stress-induced apoptosis through the regulation of the PERK- eIF2α signaling pathway, suggesting that it is a possible candidate for liver disease therapy.展开更多
AIM: To investigate the effect of high concentration of glucose(HCG) on double stranded RNA-activated protein kinase-like ER kinase(PERK)-eukaryotic initiation factor-2α(eIF2α)-transcription factor C/EBP homologous ...AIM: To investigate the effect of high concentration of glucose(HCG) on double stranded RNA-activated protein kinase-like ER kinase(PERK)-eukaryotic initiation factor-2α(eIF2α)-transcription factor C/EBP homologous protein(CHOP)-cysteine aspartate specific proteinase(caspase-12) signaling pathway activation and apoptosis in rabbit corneal epithelial cells(RCECs). METHODS: RCECs were treated by different concentrations of glucose for 0-48 h. The expressions of PERK, p-PERK, eIF2α, p-eIF2α, 78 k Da glucose-regulated protein 78(GRP78), CHOP, B-cell lymphoma 2(Bcl-2), B-cell lymphoma-2-associated X protein(Bax) and caspase-12 were determined by Western blot. Apoptosis was detected by TUNEL assay. Meanwhile, the function of PERK-eI F2α-CHOP-caspase-12 signaling pathway activation in high glucose-induced apoptosis was evaluated using PERK inhibitor, GSK2606414. RESULTS: HCG significantly promoted the expression of p-PERK, p-eIF2α, GRP78, CHOP, Bax and cleaved caspase-12 in RCECs(P<0.05), while remarkably decreased the expression of Bcl-2 and caspase-12(P<0.05), and the alterations caused by glucose were in concentration-and time-dependent manners. Meanwhile, PERK and eIF2α expressions were not affected in all groups(P>0.05). TUNEL assay showed that the apoptosis rate of RCECs in the HCG group increased significantly in contrast with that in the normal concentration of glucose or osmotic pressure control group(P<0.05), and the apoptosis rate increased with the increase of glucose concentration within limits(P<0.05). GSK2606414 down-regulated the expression of p-PERK and p-eI F2α in the HCG group(P<0.05), while still did not affect the expression of PERK and eIF2α among groups(P>0.05). Correspondingly, GSK2606414 also significantly reduced the apoptosis rate induced by high glucose(P<0.05). CONCLUSION: HCG activates PERK-eIF2α-CHOPcaspase-12 signaling pathway and promotes apoptosis of RCECs.展开更多
Background:Rotavirus(RV)is a major pathogen that causes severe gastroenteritis in infants and young animals.Endoplasmic reticulum(ER)stress and subsequent apoptosis play pivotal role in virus infection.However,the pro...Background:Rotavirus(RV)is a major pathogen that causes severe gastroenteritis in infants and young animals.Endoplasmic reticulum(ER)stress and subsequent apoptosis play pivotal role in virus infection.However,the protective mechanisms of intestinal damage caused by RV are poorly defined,especially the molecular pathways related to enterocytes apoptosis.Thus,the aim of this study was to investigate the protective effect and mechanism of sodium butyrate(SB)on RV-induced apoptosis of IPEC-J2 cells.Results:The RV infection led to significant cell apoptosis,increased the expression levels of ER stress(ERS)markers,phosphorylated protein kinase-like ER kinase(PERK),eukaryotic initiation factor 2 alpha(eIF2α),caspase9,and caspase3.Blocking PERK pathway using specific inhibitor GSK subsequently reversed RV-induced cell apoptosis.The SB treatment significantly inhibited RV-induced ERS by decreasing the expression of glucose regulated protein 78(GRP78),PERK,and eIF2α.In addition,SB treatment restrained the ERS-mediated apoptotic pathway,as indicated by downregulation of C/EBP homologous protein(CHOP)mRNA level,as well as decreased cleaved caspase9 and caspase3 protein levels.Furthermore,siRNA-induced GPR109a knockdown significantly suppressed the protective effect of SB on RV-induced cell apoptosis.Conclusions:These results indicate that SB exerts protective effects against RV-induced cell apoptosis through inhibiting ERS mediated apoptosis by regulating PERK-eIF2αsignaling pathway via GPR109a,which provide new ideas for the prevention and control of RV.展开更多
基金supported by the National Natural Science Fund of China(Grant Nos.:31800293 and 32370422)Project of Standard for TCM(Grant No.:ZYBZH-Y-JIN-34).
文摘Ulcerative colitis(UC)is an idiopathic,relapsing,and etiologically complicated chronic inflammatory bowel disease.Despite substantial progress in the management of UC,the outcomes of mucosal barrier repair are unsatisfactory.In this study,phillygenin(PHI)treatment alleviated the symptoms of chronic colitis in mice,including body weight loss,severe disease activity index scores,colon shortening,splenomegaly,oxidative stress,and inflammatory response.In particular,PHI treatment ameliorated the tight junction proteins(TJs)reduction,fibrosis,apoptosis,and intestinal stem cell activity,indicating that PHI exerted beneficial effects on the intestinal mucosal barrier in mice with chronic colitis.In the NCM460 cells damage model,dextran sulfate sodium triggered the sequential induction of TJs reduction,fibrosis,and apoptosis.Takeda G protein-coupled receptor-5(TGR5)dysfunction mediated NCM460 cell injury.Moreover,PHI treatment enhanced TJs and suppressed fibrosis and apoptosis to maintain NCM460 cell function,depending on TGR5 activation.PHI promoted TGR5 activation and elevated intracellular cyclic adenosine monophosphate levels in HEK 293T cells transfected with TGR5 expression plasmids.Cellular thermal shift assay and molecular docking studies confirmed that PHI directly binds to TGR5,indicating that PHI is an agonist of TGR5.The process of PERK-eIF2α pathway-mediated endoplasmic reticulum Ca^(2+) release was involved in NCM460 cell injury as well,which was associated with TGR5 dysfunction.When NCM460 cells were pretreated with PHI,the PERK-eIF2α pathway and elevated Ca^(2+) levels were blocked.In conclusion,our study demonstrated a novel mechanism that PHI inhibited the PERK-eIF2α-Ca^(2+) pathway through TGR5 activation to against DSS-induced TJs reduction,fibrosis,and apoptosis.
基金supported by grants from Natural Science Foundation of Jiangsu Higher Education Institutions of China(No.13KJB360010)Jiangsu Collaborative Innovation Center of Traditional Chinese Medicine(TCM) Prevention and Treatment of Tumor(No.012092002002)+1 种基金China and Europe Taking Care of Healthcare Solutions,CHETCH(No.PIRSES-GA-2013-612589)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘5-Hydroxymethylfurfural （5-HMF）, a water-soluble compound extracted from wine-processed Fructus corni, is a novel hepatic protectant for treating acute liver injury. The present study was designed to investigate the protective effect of 5-HMF in human L02 hepatocytes injured by D-galactosamine （GAIN） and tumor necrosis factor-α （TNF-α） in vitro and to explore the underlying mechanisms of action. Our results showed that 5-HMF caused significant increase in the viability of L02 cells injured by GalN/TNF-α, in accordance with a dose-dependent decrease in apoptotic cell death confirmed by morphological and flow cytometric analyses. Based on immunofluorescence and Western blot assays, we found that GalN/TNF-α induced ER stress in the cells, as indicated by the disturbance of intracellular Ca^2＋ concentration, the activation of protein kinase RNA （PKR）-like ER kinase （PERK）, phosphorylation of eukaryotic initiation factor 2 alpha （eIF2α）, and expression of ATF4 and CHOP proteins, which was reversed by 5-HMF pre-treatment in a dose-dependent manner. The anti-apoptotic effect of 5-HMF was further evidenced by balancing the expression of Bcl-2 family members. In addition, the knockdown of PERK suppressed the expression of phospho-PERK, phospho-eIF2α, ATF4, and CHOP, resulting in a significant decrease in cell apoptosis after the treatment with GalN/TNF-α. 5-HMF could enhance the effects of PERK knockdown, protecting the cells against the GalN/TNF-α insult. In conclusion, these findings demonstrate that 5-HMF can effectively protect GalN/TNF-α-injured L02 hepatocytes against ER stress-induced apoptosis through the regulation of the PERK- eIF2α signaling pathway, suggesting that it is a possible candidate for liver disease therapy.
基金Supported by Shanghai Natural Science Foundation (No.19ZR1450500)National Foundation Cultivation Project of Tongji University (No.22120180285)the Good Physician Training Project of Yangpu District, Shanghai
文摘AIM: To investigate the effect of high concentration of glucose(HCG) on double stranded RNA-activated protein kinase-like ER kinase(PERK)-eukaryotic initiation factor-2α(eIF2α)-transcription factor C/EBP homologous protein(CHOP)-cysteine aspartate specific proteinase(caspase-12) signaling pathway activation and apoptosis in rabbit corneal epithelial cells(RCECs). METHODS: RCECs were treated by different concentrations of glucose for 0-48 h. The expressions of PERK, p-PERK, eIF2α, p-eIF2α, 78 k Da glucose-regulated protein 78(GRP78), CHOP, B-cell lymphoma 2(Bcl-2), B-cell lymphoma-2-associated X protein(Bax) and caspase-12 were determined by Western blot. Apoptosis was detected by TUNEL assay. Meanwhile, the function of PERK-eI F2α-CHOP-caspase-12 signaling pathway activation in high glucose-induced apoptosis was evaluated using PERK inhibitor, GSK2606414. RESULTS: HCG significantly promoted the expression of p-PERK, p-eIF2α, GRP78, CHOP, Bax and cleaved caspase-12 in RCECs(P<0.05), while remarkably decreased the expression of Bcl-2 and caspase-12(P<0.05), and the alterations caused by glucose were in concentration-and time-dependent manners. Meanwhile, PERK and eIF2α expressions were not affected in all groups(P>0.05). TUNEL assay showed that the apoptosis rate of RCECs in the HCG group increased significantly in contrast with that in the normal concentration of glucose or osmotic pressure control group(P<0.05), and the apoptosis rate increased with the increase of glucose concentration within limits(P<0.05). GSK2606414 down-regulated the expression of p-PERK and p-eI F2α in the HCG group(P<0.05), while still did not affect the expression of PERK and eIF2α among groups(P>0.05). Correspondingly, GSK2606414 also significantly reduced the apoptosis rate induced by high glucose(P<0.05). CONCLUSION: HCG activates PERK-eIF2α-CHOPcaspase-12 signaling pathway and promotes apoptosis of RCECs.
基金supported by Key Program for the National Key Research&Development Program of China(2018YFD0501004)the National Natural Science Foundation of China(31730091)the Sichuan Science and Technology Support Program(2020YFN0147).
文摘Background:Rotavirus(RV)is a major pathogen that causes severe gastroenteritis in infants and young animals.Endoplasmic reticulum(ER)stress and subsequent apoptosis play pivotal role in virus infection.However,the protective mechanisms of intestinal damage caused by RV are poorly defined,especially the molecular pathways related to enterocytes apoptosis.Thus,the aim of this study was to investigate the protective effect and mechanism of sodium butyrate(SB)on RV-induced apoptosis of IPEC-J2 cells.Results:The RV infection led to significant cell apoptosis,increased the expression levels of ER stress(ERS)markers,phosphorylated protein kinase-like ER kinase(PERK),eukaryotic initiation factor 2 alpha(eIF2α),caspase9,and caspase3.Blocking PERK pathway using specific inhibitor GSK subsequently reversed RV-induced cell apoptosis.The SB treatment significantly inhibited RV-induced ERS by decreasing the expression of glucose regulated protein 78(GRP78),PERK,and eIF2α.In addition,SB treatment restrained the ERS-mediated apoptotic pathway,as indicated by downregulation of C/EBP homologous protein(CHOP)mRNA level,as well as decreased cleaved caspase9 and caspase3 protein levels.Furthermore,siRNA-induced GPR109a knockdown significantly suppressed the protective effect of SB on RV-induced cell apoptosis.Conclusions:These results indicate that SB exerts protective effects against RV-induced cell apoptosis through inhibiting ERS mediated apoptosis by regulating PERK-eIF2αsignaling pathway via GPR109a,which provide new ideas for the prevention and control of RV.
