BACKGROUND Fibroblast growth factor(FGF)15/19,which is expressed in and secreted from the distal ileum,can regulate hepatic glucose metabolism in an endocrine manner.The levels of both bile acids(BAs)and FGF15/19 are ...BACKGROUND Fibroblast growth factor(FGF)15/19,which is expressed in and secreted from the distal ileum,can regulate hepatic glucose metabolism in an endocrine manner.The levels of both bile acids(BAs)and FGF15/19 are elevated after bariatric surgery.However,it is unclear whether the increase in FGF15/19 is induced by BAs.Moreover,it remains to be understood whether FGF15/19 elevations contribute to improvements in hepatic glucose metabolism after bariatric surgery.AIM To investigate the mechanism of improvement of hepatic glucose metabolism by elevated BAs after sleeve gastrectomy(SG).METHODS By calculating and comparing the changes of body weight after SG with SHAM group,we examined the weight-loss effect of SG.The oral glucose tolerance test(OGTT)test and area under the curve of OGTT curves were used to assess the anti-diabetic effects of SG.By detecting the glycogen content,expression and activity of glycogen synthase as well as the glucose-6-phosphatase(G6Pase)and phosphoenolpyruvate carboxykinase(Pepck),we evaluated the hepatic glycogen content and gluconeogenesis activity.We examined the levels of total BA(TBA)together with the farnesoid X receptor(FXR)-agonistic BA subspecies in systemic serum and portal vein at week 12 post-surgery.Then the histological expression of ileal FXR and FGF15 and hepatic FGF receptor 4(FGFR4)with its corresponding signal pathways involved in glucose metabolism were detected.RESULTS After surgery,food intake and body weight gain of SG group was decreased compare with the SHAM group.The hepatic glycogen content and glycogen synthase activity was significantly stimulated after SG,while the expression of the key enzyme for hepatic gluconeogenesis:G6Pase and Pepck,were depressed.TBA levels in serum and portal vein were both elevated after SG,the FXR-agonistic BA subspecies:Chenodeoxycholic acid(CDCA),lithocholic acid(LCA)in serum and CDCA,DCA,LCA in portal vein were all higher in SG group than that in SHAM group.Consequently,the ileal expression of FXR and FGF15 were also advanced in SG group.Moreover,the hepatic expression of FGFR4 was stimulated in SG-operated rats.As a result,the activity of its corresponding pathway for glycogen synthesis:FGFR4-Ras-extracellular signal regulated kinase pathway was stimulated,while the corresponding pathway for hepatic gluconeogenesis:FGFR4-cAMP regulatory element-binding protein-peroxisome proliferator-activated receptorγcoactivator-1αpathway was suppressed.CONCLUSION Elevated BAs after SG induced FGF15 expression in distal ileum by activating their receptor FXR.Furthermore,the promoted FGF15 partly mediated the improving effects on hepatic glucose metabolism of SG.展开更多
The retina of zebrafish can regenerate completely after injury.M ultiple studies have demonstrated that metabolic alte rations occur during retinal damage;however to date no study has identified a link between metabol...The retina of zebrafish can regenerate completely after injury.M ultiple studies have demonstrated that metabolic alte rations occur during retinal damage;however to date no study has identified a link between metabolites and retinal regeneration of zebrafish.Here,we performed an unbiased metabolome sequencing in the N-methyl-D-aspartic acid-damaged retinas of zebrafish to demonstrate the metabolomic mechanism of retinal regeneration.Among the differentially-ex pressed metabolites,we found a significant decrease in p-aminobenzoic acid in the N-methyl-D-aspartic acid-damaged retinas of zebrafish.Then,we investigated the role of p-aminobenzoic acid in retinal regeneration in adult zebrafish.Impo rtantly,p-aminobenzoic acid activated Achaetescute complex-like 1a expression,thereby promoting Müller glia reprogramming and division,as well as Müller glia-derived progenitor cell proliferation.Finally,we eliminated folic acid and inflammation as downstream effectors of PABA and demonstrated that PABA had little effect on Müller glia distribution.Taken together,these findings show that PABA contributes to retinal regeneration through activation of Achaetescute complex-like 1a expression in the N-methyl-Daspartic acid-damaged retinas of zebrafish.展开更多
基金the National Natural Science Foundation of China, No. 81600617
文摘BACKGROUND Fibroblast growth factor(FGF)15/19,which is expressed in and secreted from the distal ileum,can regulate hepatic glucose metabolism in an endocrine manner.The levels of both bile acids(BAs)and FGF15/19 are elevated after bariatric surgery.However,it is unclear whether the increase in FGF15/19 is induced by BAs.Moreover,it remains to be understood whether FGF15/19 elevations contribute to improvements in hepatic glucose metabolism after bariatric surgery.AIM To investigate the mechanism of improvement of hepatic glucose metabolism by elevated BAs after sleeve gastrectomy(SG).METHODS By calculating and comparing the changes of body weight after SG with SHAM group,we examined the weight-loss effect of SG.The oral glucose tolerance test(OGTT)test and area under the curve of OGTT curves were used to assess the anti-diabetic effects of SG.By detecting the glycogen content,expression and activity of glycogen synthase as well as the glucose-6-phosphatase(G6Pase)and phosphoenolpyruvate carboxykinase(Pepck),we evaluated the hepatic glycogen content and gluconeogenesis activity.We examined the levels of total BA(TBA)together with the farnesoid X receptor(FXR)-agonistic BA subspecies in systemic serum and portal vein at week 12 post-surgery.Then the histological expression of ileal FXR and FGF15 and hepatic FGF receptor 4(FGFR4)with its corresponding signal pathways involved in glucose metabolism were detected.RESULTS After surgery,food intake and body weight gain of SG group was decreased compare with the SHAM group.The hepatic glycogen content and glycogen synthase activity was significantly stimulated after SG,while the expression of the key enzyme for hepatic gluconeogenesis:G6Pase and Pepck,were depressed.TBA levels in serum and portal vein were both elevated after SG,the FXR-agonistic BA subspecies:Chenodeoxycholic acid(CDCA),lithocholic acid(LCA)in serum and CDCA,DCA,LCA in portal vein were all higher in SG group than that in SHAM group.Consequently,the ileal expression of FXR and FGF15 were also advanced in SG group.Moreover,the hepatic expression of FGFR4 was stimulated in SG-operated rats.As a result,the activity of its corresponding pathway for glycogen synthesis:FGFR4-Ras-extracellular signal regulated kinase pathway was stimulated,while the corresponding pathway for hepatic gluconeogenesis:FGFR4-cAMP regulatory element-binding protein-peroxisome proliferator-activated receptorγcoactivator-1αpathway was suppressed.CONCLUSION Elevated BAs after SG induced FGF15 expression in distal ileum by activating their receptor FXR.Furthermore,the promoted FGF15 partly mediated the improving effects on hepatic glucose metabolism of SG.
基金supported by the National Natural Science Foundation of China,Nos.81974134(to XX)and 82000895(to HL)National Key Research and Development Program of China,Nos.2021YFA1101200&2021YFA1101202National Natural Science Foundation of Hunan Province,China,No.2022JJ30071(to HL)。
文摘The retina of zebrafish can regenerate completely after injury.M ultiple studies have demonstrated that metabolic alte rations occur during retinal damage;however to date no study has identified a link between metabolites and retinal regeneration of zebrafish.Here,we performed an unbiased metabolome sequencing in the N-methyl-D-aspartic acid-damaged retinas of zebrafish to demonstrate the metabolomic mechanism of retinal regeneration.Among the differentially-ex pressed metabolites,we found a significant decrease in p-aminobenzoic acid in the N-methyl-D-aspartic acid-damaged retinas of zebrafish.Then,we investigated the role of p-aminobenzoic acid in retinal regeneration in adult zebrafish.Impo rtantly,p-aminobenzoic acid activated Achaetescute complex-like 1a expression,thereby promoting Müller glia reprogramming and division,as well as Müller glia-derived progenitor cell proliferation.Finally,we eliminated folic acid and inflammation as downstream effectors of PABA and demonstrated that PABA had little effect on Müller glia distribution.Taken together,these findings show that PABA contributes to retinal regeneration through activation of Achaetescute complex-like 1a expression in the N-methyl-Daspartic acid-damaged retinas of zebrafish.
