ObjectiveThis study aims to investigate the effect of X-box binding protein 1 (XBP1), a key signal molecule of ERS, on the insulin signaling pathway in adipocytes stimulated byPorphyromonas gingivalis(P. gingivalis)-lipopolysaccharide (LPS), a pathogenic bacterium of periodontitis.
MethodsPrimary cultured rat adipocytes were stimulated byP. gingivalis-LPS (100 ng·mL-1) for 4, 8, 12, and 24 h. The protein expression levels of insulin receptor substrate-1 (IRS-1), phosphoinositide dependent protein kinase (p-PDK-1), and protein kinase B (p-AKT-1) in the insulin signaling pathway were detected by Western blot analysis. pLVX-NC1, pLVX-XBP1, pLVX-NC2, and pLVX-XBP1-RNAi were transfected into adipocytes, respectively. The transfected rat adipocytes were stimulated byP. gingivalis-LPS, and the protein expression of the insulin signaling pathway was detected by Western blot.
ResultsThe Western Blot showed decreased protein expression of the insulin signaling pathway in rat adipocytes stimulated withP. gingivalis-LPS compared with the control, and the difference was statistically significant (P<0 .05). the protein expression levels of irs-1, p-pdk-1, and p-akt in the rat adipocytes of plvx-xbp1 were significantly higher than those in plvx-nc1 at 8 and 12 h afterP. gingivalis-LPS stimulation (P<0 .05). the protein expression levels of irs-1, p-pdk-1, and p-akt in the rat adipocytes of plvx-xbp1-rnai were significantly lower than those in plvx-nc2 at 4, 8, 12, and 24 h afterP. gingivalis-LPS stimulation (P<0 .05).
ConclusionP. gingivalis-LPS regulates the insulin signaling pathway in adipocytes th-rough XBP1.
