TLR4-TLR10-CD36的识别和炎症信号转导可能参与细胞内天然低密度脂蛋白氧化

Recognition and inflammation signal transduction of TLR4-TLR10-CD36 may be involved in natural low density lipoprotein oxidation

目的探究低密度脂蛋白(LDL)氧化的可能分子机制。方法天然LDL(100 mg/L)诱导人单核细胞系THP-1细胞0、1、3、5 h。用诱导不同时间点的单核细胞进行表达谱芯片实验,筛选与LDL氧化相关的基因。在mRNA水平和蛋白质水平上分别用实时定量PCR和Western blot进一步验证部分微阵列结果。利用DAVID数据库进行基因聚类、生物学功能以及与脂质和氧化相关的信号传导途径分析。结果LDL诱导THP-1后,细胞内大量生物膜相关基因的表达发生变化,提示脂质氧化的发生定位在生物膜上。LDL诱导3 h后细胞内脂质氧化相关基因的表达发生变化,提示脂质氧化已经开始。差异表达基因的功能注释分析发现,Toll样受体(TLR)信号通路、凋亡、内吞、细胞周期、脂质筏、脂质结合、定位、转运、细胞黏附、金属离子稳态、氧化还原等生物学通路得到不同程度的富集。天然LDL诱导THP-1不同时间点炎症因子的mRNA以及蛋白水平的表达均受到了抑制,如肿瘤坏死因子α、白细胞介素33、c-FOS等基因的表达随着LDL孵育时间的延长,其表达量逐渐降低。结论本研究提示,天然LDL的氧化可能与TLR4-TLR10-CD36的识别和炎症信号转导有关。

Aim To explore the possible molecular mechanism of low density lipoprotein(LDL)oxidation.Methods Human monocyte line THP-1 cells were induced by natural LDL(100 mg/L)for 0,1,3 and 5 hours.Induction of monocytes at different time points was for expression profile microarray experiments,and genes related to LDL oxidation were screened.Real-time quantitative PCR and Western blot were used to further validate the results of some microarrays at the levels of mRNA and protein,respectively.Gene clustering,biological functions and signal transduction pathways related to lipid and oxidation were analyzed by using the DAVID database.Results After LDL induced THP-1,the expression of a large number of genes related to biofilm in cells was changed,suggesting that lipid oxidation was localized on biofilm.The expression of lipid oxidation-related genes changed after 3 hours of LDL induction,which imply that lipid oxidation had begun.Functional annotation analysis of differentially expressed genes revealed that Toll-like receptor(TLR)signaling pathway,apoptosis,endocytosis,cell cycle,lipid raft,lipid binding,localization,transport,cell adhesion,metal ion homeostasis,redox and other biological pathways were enriched to varying degrees.The mRNA and protein expressions of inflammatory factors induced by natural LDL were inhibited at different time points in THP-1.For example,the expressions of tumor necrosis factorα,interleukin-33,c-FOS and other genes decreased gradually with the prolongation of incubation time of LDL.Conclusion This study suggests that the oxidation of natural LDL may be related to the recognition and inflammation signal transduction of TLR4-TLR10-CD36.