Role of ROCK1 in the podocyte injury induced by oxidized low-density lipoprotein

Objective To explore the role of ROCK1 in oxidized low-density lipoprotein (ox-LDL) induced podocyte injury and its possible mechanism. Methods The conditionally immortalized mouse podocyte cells were cultured in vitro and exposed to 20 μg/ml ox-LDL for 24 h. Western blotting was used to analyze the expression level of p-MYPT, nephrin, LC3-Ⅱ, p62, p-ULK1 in groups of control, ox-LDL, ROCK1 siRNA with ox-LDL, wtROCK1 with ox-LDL. Podocytes were incubated with DiI labeled ox-LDL for 4 h and fluorescence microscope was used to analyze lipid distribution. Results Compared with control group, ox-LDL increased cell cholesterol accumulation, activated ROCK along with decreased nephrin, LC3-Ⅱ(P＜0.05), and increased p62, and p-ULK1 expression (P＜0.05). Over-expression of ROCK1 significantly decreased the expression of nephrin and LC3-Ⅱ, but up-regulated the levels of p62, p-ULK1 and cell cholesterol accumulation in ox-LDL stimulated podocytes (P＜0.05). In contrast, Inhibition of ROCK1 protected podocyte by improved lipophagy. Conclusion ROCK1 mediated disfunction of lipophagy contributes to the ox-LDL induced podocyte injury.