高密度脂蛋白对氧化型低密度脂蛋白刺激下脂肪细胞TNF-α表达的影响

High density lipoprotein suppresses oxidized low density lipoprotein-induced tumor necrosis factor-α in 3T3-L1 adipocytes

目的观察高密度脂蛋白(high density lipoprotein,HDL)对氧化型低密度脂蛋白(oxidized low density lipoprotein,oxLDL)刺激下3T3-L1脂肪细胞肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)mRNA表达的影响,并探讨其可能的作用机制。方法 3T3-L1脂肪细胞促分化成熟后,oxLDL刺激脂肪细胞,给予不同浓度的HDL(10～100μg/ml),及H-89(10μmol/L)+HDL(100μg/ml)干预,收集细胞,测定脂肪细胞TNF-αmRNA表达水平,IκB蛋白浓度及核因子-κB(NF-κB)活性。结果 OxLDL刺激使3T3-L1脂肪细胞TNF-αmRNA表达及NF-κB活性明显增强。HDL浓度依赖性抑制TNF-αmRNA表达、NF-κB活化和IκB降解。与oxLDL刺激组比较,100μg/ml HDL使TNF-αmRNA表达降低64.5%,NF-κB活性减少49%,并明显增加IκB蛋白水平。HDL的这些抗炎效应能被蛋白激酶A(PKA)抑制剂H-89部分抑制。结论HDL能抑制oxLDL诱导的3T3-L1脂肪细胞TNF-αmRNA表达,PKA-IκB-NF-κB信号通路是其中作用途径之一,该效应不需要HDL与oxLDL的直接接触作用。

Objective To determine the effect of high density lipoprotein （HDL） on the mRNA ex- pression of tumor necrosis factor-α （TNF-α） in oxidized low density lipoprotein （oxLDL）-stimulated 3T3-L1 adipocytes. Methods Fully differentiated 3T3-LI adipocytes were incubated in the medium containing various concentrations of HDL （10 to 100 μg/ml） with oxLDL （50 μg/ml） stimulation, with/without H-89 （10 μmol/L） preincubation. TNF-αmRNA expression was determined by RT-PCR, NF-κB activity was measured by ELISA, and IKB protein level was tested by Western blotting. Results OxLDL stimulation induced a significant increase of TNF-α mRNA and NF-κB activity in 3T3-L1 adipocytes. HDL inhibited TNF-α mRNA expression, NF-κB activation and IKB degradation in a dose-dependent manner. Compared with oxLDL stimulation, HDL at 100μg/ml resulted in a decrease of TNF-α mRNA expression by 64.5% and NF-κB activation by 49%, and an increase of IKB protein. The anti-inflammatory effect of HDL was abolished by PKA inhibitor H-89 partially. Conclusion HDL could suppress TNF-α mRNA expression in PKA- IKBa-NF-κB signaling pathway, without any direct contact oxLDL-stimulated 3T3-L1 adipocytes through between HDL and oxLDL.