Objective: To study the effects of cytoskeleton reorganization inhibition with LIMK2 RNAi upon the mechanosensitivity of c-fos gene in osteoblast.
Methods: Mouse primary osteoblast was treated with LIMK2 specific siRNA (RNAi Group), negative control siRNA (NC Group), and then were loaded or unloaded by fluid shear stress. Real-time PCR and immunofluorescence were used to detect the c-fos expression levels and statistics analysis was performed.
Results: When the cytoskeleton reorganization was inhibited with RNAi only, the c-fos mRNA (0.0108 +/- 0.0074 and 0.0042 +/- 0.0018, t = -1.86, P > 0.05) and protein (121 +/- 7 and 119 +/- 6, t = -1.272, P > 0.05) expression levels of each unloaded group had no significant difference; Fluid shear stress could up-regulate the c-fos mRNA (0.2203 +/- 0.1532 vs 0.0042 +/- 0.0018, t = -707.35, P < 0.05)and protein (178 +/- 12 vs 119 +/- 6, t = -30.761, P < 0.05) expression; After the cytoskeleton reorganization was inhibited with RNAi, the c-fos mRNA (0.5280 +/- 0.0879 vs 0.2203 +/- 0.1532, t = -1007.00, P < 0.05) and protein (224 +/- 46 vs 178 +/- 12, t = -6.853, P < 0.05) expression induced by fluid shear stress had significant difference. Cytoskeleton reorganization inhibition with RNAi had synergistic effect upon the expression of c-fos mRNA (F = 84.388, P < 0.05) and protein (F = 42.409, P < 0.05) induced by fluid shear stress.
Conclusion: Using RNAi against LIMK2 to inhibit the cytoskeleton reorganization can promote the expression of c-fos gene and thus enhance the mechanosensitivity of c-fos gene in osteoblast.