SIRT1对肿瘤坏死因子-alpha诱导的3T3-L1脂肪细胞中CD40表达的影响

Objective: To explore the effect of SIRT1 on tumor necrosis factor-alpha (TNF-α) -induced CD40 expression in 3T3-L1 adipocytes and its underlying mechanism. Methods: 3T3-L1 preadipocytes were cultured by enzymatic digestion method. The location of SIRT1 in 3T3-L1 adipocytes was studied by immunofluorescent staining. CD40 gene and protein expression were examined by Real-time PCR and Western blot analysis. In order to further study the effect of SIRT1 on CD40 expression and underlying signal pathway, activators and inhibitors of SIRT1 was used to activate and inhibit the effect of SIRT1 and to observe the expression change of CD40. Results: SIRT1 was expressed in both the cytoplasm and nucleus of 3T3-L1 adipocytes. The protein and mRNA expressions of CD40 were obviously increased in TNF-α-treated adipocytes in a dose-dependent manner, and significantly increase at 10 ng/ml (P < 0.01). So we chose the concentration of 10 ng/ml as the best stimulus dose of TNF-α. The stimulation effect of TNF-α was also time-dependent, with the stimulation time extension, the expression of CD40 was increased. Further study demonstrated that SIRT1 regulates the expression of CD40 induced by TNF-α in 3T3-L1 adipocytes via NF-κB pathway. Conclusions：SIRT1 regulates the expression of CD40 induced by TNF-α via NF-κB pathway in 3T3-L1 adipocytes.