滇黄精变种多糖通过干预PI3K/AKT 通路改善HepG2细胞脂肪变性的研究OA

Objective To investigate the ameliorative effect of PKVP-1,a polysaccharide from a variant of Dianhuangjing(Polygonatum kingianum Coll.et Hemsl.),on oleic acid-induced steatosis in HepG2 cells,and to elucidate its potential molecular mechanism from the perspective of the phosphatidylinositol 3-kinase/protein kinase B(PI3K/AKT)signaling pathway.Methods HepG2 cells were used to establish a hepatocellular steatosis model induced by 0.5 mM oleic acid.A blank group,a model group,and PKVP-1 low-,medium-,and high-dose groups(50,100,200 mg/mL)were set for intervention.The CCK-8 assay was used to determine the safe working concentrations of PKVP-1.An intracellular triglyceride(TG)assay kit was used to measure intracellular TG content,and Oil Red O staining was performed to assess intracellular lipid accumulation.Western blotting was used to determine the expression levels of key proteins in the PI3K/AKT pathway,including PI3K,phosphorylated phosphatidylinositol 3-kinase(p-PI3K),AKT,phosphorylated protein kinase B(p-AKT),and downstream lipid synthesis-related proteins sterol regulatory element-binding protein 1c(SREBP-1c)and fatty acid synthase(FAS).Immunofluorescence was used to verify SREBP-1c protein expression.Results PKVP-1 at concentrations of 300 mg/mL and above reduced HepG2 cell viability(P<0.01);therefore,50-200 mg/mL was selected as the intervention concentration range.Compared with the blank group,the model group showed significantly increased intracellular TG content(P<0.001)and marked lipid droplet accumulation,significantly decreased p-PI3K/PI3K and p-AKT/AKT protein expression ratios(P<0.001),and significantly upregulated SREBP-1c and FAS protein expression(P<0.001).Compared with the model group,PKVP-1 dose-dependently reduced intracellular TG content(P<0.001)and lipid droplet accumulation,significantly increased the p-PI3K/PI3K and p-AKT/AKT protein expression ratios(P<0.001),and downregulated SREBP-1c and FAS protein expression(P<0.001).Immunofluorescence results further confirmed that PKVP-1 dose-dependently inhibited SREBP-1c fluorescence intensity(P<0.01,P<0.001).Conclusion PKVP-1 effectively ameliorated oleic acid-induced steatosis in HepG2 cells.The underlying mechanism may be associated with activation of the PI3K/AKT signaling pathway,leading to downregulation of the key downstream lipogenic proteins SREBP-1c and FAS,thereby inhibiting endogenous fatty acid synthesis in hepatocytes and reducing abnormal lipid accumulation.