Intestinal dysbiosis and disrupted bile acid(BA)homeostasis are associated with obesity,but the precise mechanisms remain insufficiently explored.Hepatic protein phosphatase 1 regulatory subunit 3G(PPP1R3G)plays a piv...Intestinal dysbiosis and disrupted bile acid(BA)homeostasis are associated with obesity,but the precise mechanisms remain insufficiently explored.Hepatic protein phosphatase 1 regulatory subunit 3G(PPP1R3G)plays a pivotal role in regulating glycolipid metabolism;nevertheless,its obesity-combatting potency remains unclear.In this study,a substantial reduction was observed in serum PPP1R3G levels in high-body mass index(BMI)and high-fat diet(HFD)-exposed mice,establishing a positive correlation between PPP1R3G and non-12a-hydroxylated(non-12-OH)BA content.Additionally,hepatocyte-specific overexpression of Ppp1r3g(PPP1R3G HOE)mitigated HFD-induced obesity as evidenced by reduced weight,fat mass,and an improved serum lipid profile;hepatic steatosis alleviation was confirmed by normalized liver enzymes and histology.PPP1R3G HOE considerably impacted systemic BA homeostasis,which notably increased the non-12-OH BAs ratio,particularly lithocholic acid(LCA).16S ribosomal DNA(16S rDNA)sequencing assay indicated that PPP1R3G HOE reversed HFD-induced gut dysbiosis by reducing the Firmicutes/Bacteroidetes ratio and Lactobacillus population,and elevating the relative abundance of Blautia,which exhibited a positive correlation with serum LCA levels.A fecal microbiome transplantation test confirmed that the anti-obesity effect of hepatic PPP1R3G was gut microbiotadependent.Mechanistically,PPP1R3G HOE markedly suppressed hepatic cholesterol 7a-hydroxylase(CYP7A1)and sterol-12a-hydroxylase(CYP8B1),and concurrently upregulated oxysterol 7-a hydroxylase and Takeda G protein-coupled BA receptor 5(TGR5)expression under HFD conditions.Furthermore,LCA administration significantly mitigated the HFD-induced obesity phenotype and elevated non-12-OH BA levels.These findings emphasize the significance of hepatic PPP1R3G in ameliorating diet-induced adiposity and hepatic steatosis through the gut microbiota-BA axis,which may serve as potential therapeutic targets for obesity-related disorders.展开更多
基金supported by the Natural Science Foundation for Young Scientists of China(Grant No.:82201545)the Natural Science Foundation of Jiangsu Province,China(Grant No.:BK20221221)+4 种基金the Practice Innovation Program of Jiangsu Province,China(Grant No.:KYCX21_2641)the Medical Science Foundation of Jiangsu Province,China(Grant No.:H2019007)the Key Medical Talents Training Project of Xuzhou,China(Grant No.:XWRCHT20220060)the Xuzhou“Pengcheng Talent”Youth Medical Reserve Talent Project,China(Grant No.:XWRCHT20220014)the Science and Technology Projects of Xuzhou,China(Grant No.:KC21061).
文摘Intestinal dysbiosis and disrupted bile acid(BA)homeostasis are associated with obesity,but the precise mechanisms remain insufficiently explored.Hepatic protein phosphatase 1 regulatory subunit 3G(PPP1R3G)plays a pivotal role in regulating glycolipid metabolism;nevertheless,its obesity-combatting potency remains unclear.In this study,a substantial reduction was observed in serum PPP1R3G levels in high-body mass index(BMI)and high-fat diet(HFD)-exposed mice,establishing a positive correlation between PPP1R3G and non-12a-hydroxylated(non-12-OH)BA content.Additionally,hepatocyte-specific overexpression of Ppp1r3g(PPP1R3G HOE)mitigated HFD-induced obesity as evidenced by reduced weight,fat mass,and an improved serum lipid profile;hepatic steatosis alleviation was confirmed by normalized liver enzymes and histology.PPP1R3G HOE considerably impacted systemic BA homeostasis,which notably increased the non-12-OH BAs ratio,particularly lithocholic acid(LCA).16S ribosomal DNA(16S rDNA)sequencing assay indicated that PPP1R3G HOE reversed HFD-induced gut dysbiosis by reducing the Firmicutes/Bacteroidetes ratio and Lactobacillus population,and elevating the relative abundance of Blautia,which exhibited a positive correlation with serum LCA levels.A fecal microbiome transplantation test confirmed that the anti-obesity effect of hepatic PPP1R3G was gut microbiotadependent.Mechanistically,PPP1R3G HOE markedly suppressed hepatic cholesterol 7a-hydroxylase(CYP7A1)and sterol-12a-hydroxylase(CYP8B1),and concurrently upregulated oxysterol 7-a hydroxylase and Takeda G protein-coupled BA receptor 5(TGR5)expression under HFD conditions.Furthermore,LCA administration significantly mitigated the HFD-induced obesity phenotype and elevated non-12-OH BA levels.These findings emphasize the significance of hepatic PPP1R3G in ameliorating diet-induced adiposity and hepatic steatosis through the gut microbiota-BA axis,which may serve as potential therapeutic targets for obesity-related disorders.
