oxLDL/β2GPⅠ/β2GPⅠ-Ab复合物调节A7r5表型转化及脂质转运分子表达

OxLDL/β2GPⅠ/β2GPⅠ-Ab complex in regulating the phenotypic transformation of A7r5 and the expression of lipid transporters

目的探讨氧化型低密度脂蛋白/β2糖蛋白Ⅰ/抗β2糖蛋白Ⅰ抗体复合物(oxLDL/β2GPⅠ/β2GPⅠ-Ab complex)对大鼠胸主动脉平滑肌细胞株(A7r5)表型转化和细胞表面脂质转运分子的影响,以及toll样受体4(toll like receptor 4,TLR4)信号通路在其中的作用。方法分别用oxLDL、oxLDL/β2GPⅠ复合物、oxLDL/抗β2GPⅠ抗体复合物、β2GPⅠ/抗β2GPⅠ抗体复合物、oxLDL/β2GPⅠ/抗β2GPⅠ抗体复合物刺激A7r5,收集总RNA和蛋白质,利用实时定量PCR、western blot及免疫荧光染色等方法检测细胞α-平滑肌肌动蛋白(α-smooth muscle actin,α-SMA)、巨噬细胞表面标志CD68、半乳糖凝集素3(galectin-3,LGALS3)、B类清道夫受体3(CD36)和ATP结合盒转运体(ATP-binding cassette transporter)A1/G1(ABCA1/ABCG1)的表达情况;用TLR4阻断剂TAK-242(5μmol/L)或c-Jun氨基末端激酶1/2(c-Jun N-terminal kinases 1/2,JNK 1/2)阻断剂SP600125(90 nmol/L)预处理的方式,观察TLR4及下游信号分子在oxLDL/β2GPⅠ/β2GPⅠ-Ab复合物诱导A7r5表型转化和脂质转运分子表达变化的作用。结果 oxLDL/β2GPⅠ/β2GPⅠ-Ab复合物明显上调细胞CD68和LGALS3水平,降低α-SMA表达,而TAK-242能够反转该现象;oxLDL/β2GPⅠ/β2GPⅠ-Ab复合物能够促进细胞表达CD36,同时抑制ABCA1/ABCG1表达,TAK-242和SP600125能够逆转该过程。结论 oxLDL/β2GPⅠ/β2GPⅠ-Ab复合物促进A7r5细胞向"巨噬样"细胞发生表型转变,调节脂质转运相关分子的表达,增强脂质向细胞内转运的能力;TLR4和JNK1/2与该过程密切相关。

Objective To investigate the effects of oxidized low-density lipoprotein/β2 glycoproteinⅠ/β2 glycoproteinⅠantibody ( oxLDL /β2GPⅠ/β2GPⅠ-Ab) complex on the phenotypic transformation and lipid transpoters on the surface of rat thoracic aorta smooth muscle cell line (A7r5), and their correlation with toll-like receptor 4 (TLR4) signaling pathway. Methods A7r5 cells were stimulated by oxLDL, oxLDL/β2GPⅠ complex, oxLDL/β2GPⅠ-Ab complex,β2GPⅠ/β2GPⅠ-Ab complex and oxLDL/β2GPⅠ/β2GPⅠ-Ab complex respectively, and then total RNA and protein were collected. The expressions of α-smooth muscle actin (α-SMA), macrophage surface marker CD68, galectin-3 (LGALS3), scavenger receptor class B member 3 (CD36) and ATP-binding cassette transporter A1/G1 (ABCA1/ABCG1) were detected by real-time quantitative PCR (RT-qPCR), western blot and immunofluorescence (IF) respectively. The roles of TLR4 and its downstream signaling molecules in the phenotypic transformation and expression changes of lipid transporters of A7r5 cells induced by oxLDL/β2GPⅠ/β2GPⅠ-Ab complex were investigated by the pretreatment of TLR4 blocker TAK-242 (5 μmol/L) or c-Jun N-terminal kinases 1/2 (JNK 1/2) blocker SP600125 (90 nmol/L). Results The oxLDL /β2GPⅠ/β2GPⅠ-Ab complex significantly increased the levels of CD68 and LGALS3, and decreased the level of α-SMA, while TAK-242 could reverse this phenomenon. The oxLDL/β2GPⅠ/β2GPⅠ-Ab complex could promote the expression of CD36 and inhibit the expression of ABCA1/ABCG1, while TAK-242 and SP600125 could reverse this process. Conclusion The oxLDL/β2GPⅠ/β2GPⅠ-Ab complex promotes the phenotypic transformation of A7r5 cells to macrophage-like cells, regulates the expression of lipid transport-related molecules and enhances the ability of lipids transport into cells. TLR4 and JNK1/2 are closely related to this process.