摘要目的 探讨alpha7烟碱型乙酰胆碱受体(α7nAChR)对乳糜微粒(CM)介导的脂肪细胞促酰化蛋白(ASP)表达及其机制.方法 诱导培养3T3-L1前脂肪细胞分化成熟;酶联免疫吸附试验(ELISA)测定ASP和其前体补体C3(C3)表达;Western blot法测定p38丝裂原活化蛋白激酶(p38)及磷酸化p38(p-p38)表达;实时定量聚合酶链反应(Real-time PCR)检测ASP受体C5L2表达.结果 烟碱(1.0×10-9、1.0×10-8、1.0×10-7 mol/L)呈浓度依赖性抑制CM(200 μg TG/ml,24 h)介导的C3和ASP表达上调(P＜0.05),α7nAChR特异性阻断剂α-银环蛇神经毒素(α-BTX)拮抗烟碱(10-8mol/L)介导这一效应[ASP (pmol/mg cell protein):0.81±0.35比0.71 ±0.22,P＜0.05;C3(pmol/mg cell protein):16.37±1.64比12.75±0.88,P＜0.05];α7nAChR抑制CM介导的p-p38上调(1.65 ±0.11比2.18±0.23,P＜0.05),p38特异性抑制剂SB203580预处理组p-p38及C3较CM处理组明显降低[C3 (pmol/mg cell protein):14.72±1.31比19.34±1.49,P＜0.05和p-p38:1.59 ±0.26比2.09±0.32,P＜0.05];α7nAChR抑制CM介导的C5L2 mRNA表达下调(0.56±0.08比0.44±0.14,P＜0.05).结论 α7nAChR通过下调C3及恢复C5L2表达进而抑制CM介导脂肪细胞的ASP表达上调,p38信号通路参与调控C3的表达.

abstractsObjective To investigate the effects of alpha7 nicotine acetylcholine receptor (α7nAChR) on chylomicron (CM)-induced acylation stimulating protein (ASP) expression and its related mechanisms.Methods 3T3-L1 preadipocytes were cultured and induced to differentiate.The expression of complement C3 (C3) and ASP was assessed by enzyme-linked immunosorbent assay (ELISA).The total p38 mitogen-activated protein kinases (p38) and phosphorylated p38 (p-p38) were determined by Western blotting.C5a like receptor 2 (C5L2) mRNA was detected by real-time quantitative polymerase chain reaction (Real-time PCR).Results α7nAChR agonist nicotine (1.0 × 10-9,1.0 × 10-8,1.0 × 10-7 mol/L) pretreatment inhibited CM (200 μg TG/ml,24 h)-induced C3 and ASP release in 3T3-L1 adipocytes (P ＜0.05),an effect attenuated by α7nAChR selective nicotinic antagonist α-Bungarotoxin (α-BTX) [ASP (pmol/mg cell protein):0.81 ± 0.35 vs.0.71 ± 0.22,P ＜ 0.05;C3 (pmoL/mg cell protein):16.37 ±1.64 vs.12.75 ±0.88,P＜0.05].Furthermore,the inhibition of C3 expression by α7nAChR appears to be mediated by a reduction in phosphorylation of p38 (1.65 ±0.11 vs.2.18 ±0.23,P ＜0.05).In addition,αTnAChR inhibits CM-induced C5L2 mRNA downregulation (0.56 ± 0.08 vs.0.44 ± 0.14,P ＜ 0.05).Conclusion α7nAChR inhibits CM-induced ASP upregulation through downregulating C3 and restoring C5L2 mRNA.p38 signaling transduction pathway may be involved in the regulation of C3 expression.