Oxidized Low-density Lipoprotein Increases The Migration Of Artery Smooth Muscle Cells Through The Upregulation Of Netrin-1

Background:Smooth muscle cell migration are known to play a critical role in the development of Atherosclerosis.Oxidized low-density lipoprotein (oxLDL) is involved in the generation of atherosclerotic lesions. Recent studies have indicated that oxLDL is a well-established risk factor for atherosclerosis that induces vascular smooth muscle cell (VSMC) proliferation and migration, however, the exact mechanisms involved have not been fully elucidated. Recent studies show that neuroimmune Guidance Cue Netrin-1can affect a few species of cells migration,including Monocytes/Macrophages、neutrophil and smooth muscle cell.It has been reported that conditioned medium from oxLDL treated macrophages induces migration of SMCs, So we speculate that oxLDL can induce the migration of SMCs through the upregulation of netrin-1.Objective:The aim of this study is to explore if oxLDL can induce SMCs migration through upregulation of netrin-1.Methods: The experimental group of the Primary rat thoracic aortic smooth muscle cells was treated with50mg/1of oxLDL, while the cells without the treatment of the oxLDL serve as the control. The total RNAs and the proteins were extracted for the cells of the experimental group24hours after the treatment with oxLDL. The expression of netrin-1in the ox-LDL-treated cells relative to the control was evaluated at the transcriptional and translational level using Real-time PCR and western blot respectively. The Primary rat thoracic aortic smooth muscle cells was treated with the250ng/ml of netrin-1protein for48hours and the cells without the treatment serve as the control. After the48-hr incubation, both the netrin-1-treated cells and the cells of the control group were plated into the transwell and their migration were determined16hours after.Results:Compared to the control group, increased expression of the netrin-1gene at both the transcriptional and translational level was observed in the cells treated with oxLDL, which is statistically significant (P<0.05). In addition, treatment with either netrin-1protein or oxLDL can enhance the migration of Primary rat thoracic aortic smooth muscle cells, which is statistically significant (P<0.05).Conclusion:OxLDL is able to upregulate the expression of the netrin-1gene in Primary rat thoracic aortic smooth muscle cells at both the transcriptional and translational level. Furthermore, the treatment with netrin-1protein can enhance the ability of Primary rat thoracic aortic smooth muscle cells to migrate. Taken together, it seems that the oxLDL is likely to affect the migration of the Primary rat thoracic aortic smooth muscle cells by regulation of the netrin-1expression.