Potential signal pathway of all-trans retinoic acid for MMP-2 and MMP-9 expression in injury podocyte induced by adriamycin

All-trans-retinoic acid (ATRA) can regulate some specific genes expression in various tissue and cells via nuclear retinoic acid receptors (RARs), including three subtypes: retinoic acid receptor-alpha (RAR-alpha), retinoic acid receptor-beta (RAR-beta) and retinoic acid receptor-gamma (RAR-gamma). Podocyte injury plays a pivotal role in the progression of glomerulosclerosis (GS). This study was performed to study the potential signal pathway of ATRA in the expression of matrix metalloproteinases-2 (MMP-2) and matrix metalloproteinases-9 (MMP-9) in injury podocyte. Cells were divided into three groups: group of negative control (NC), group of injury podocyte induced by adriamycin (ADR) (AI) and group of ADR inducing podocyte injury model treated with ATRA (AA). The cells morphology changes were detected using microscope and scanning electron microscopy. MMP-2 and MMP-9 enzymic activity was detected using the gelatin zymography method. Protein and mRNA expressions of MMP-2, MMP-9, RAR-alpha, RAR-beta and RAR-gamma were measured by western-blot and real-time RT-PCR. Enzymatic activity of MMP-2 and MMP-9 in group AA was significantly enhanced compared to AI group after ATRA-treated 24 h (p<0.05). The protein and mRNA expressions of MMP-2/MMP-9 in group AA were significantly increased than those in group AI at both 12 and 24 h time points (p<0.05). Compared to group AI, RAR-alpha and RAR-gamma protein/mRNA expressions of group AA were significantly increased at both 12 and 24 h time points (p<0.05). There was no difference for the expression of RAR-beta between group AI and group AA (p>0.05). RAR-alpha protein level was positively correlated with MMP-2 or MMP-9 protein expression (p<0.05), and RAR-gamma protein level was also positively correlated with MMP-2 or MMP-9 protein expression (p<0.05). In conclusion, ATRA may increase expression of MMP-2 and MMP-9 by the potential signal pathway of RAR-alpha and RAR-gamma in injury podocyte induced by adriamycin, but not RAR-beta.