Matrine pre-treatment suppresses AGEs- induced HCSMCs fibrotic responses by regulating Poldip2/mTOR pathway

The fibrotic response of vascular smooth muscle cells (VSMCs) takes responsibilities in atherosclerosis. Advanced glycation end products (AGEs) induce and promote the fibrotic responses of VSMCs. Matrine shows potent anti-fibrotic and cardio-protective effects. This study was aimed to investigate the underlying mechanisms of matrine's inhibitory effects on AGEs-induced VSMCs fibrotic responses. Cultured human coronary smooth muscle cells (HCSMCs) were pre-treated with matrine and exposed to AGEs. Specific siRNA was used to silence polymerase delta interacting protein 2 (Poldip2) expression. Sircol collagen assay was used to assess collagen content. Protein expression and phosphorylation levels were determined by Western blotting. Matrine pre-treatment significantly reduced collagen content, increased smooth muscle myosin heavy chain 11 (MYH11) and Poldip2 expression, decreased expressions of collagen I, β1-integrin, phsphoinositide-3-kinase (PI3K) and nuclear phosphorylated p70S6k, and reduced phosphorylation levels of protein kinase B (Akt) and mechanistic target of rapamycin (mTOR) in HCSMCs exposed to AGEs in a concentration dependent manner. Specific siRNA effectively silenced Poldip2 expression and impaired matrine's effect on collagen content, expressions of MYH11, collagen I, β1-integrin, PI3K, nuclear p-p70S6k and phosphorylation levels of Akt and mTOR in HCSMCs exposed to AGEs. Matrine suppresses AGEs- induced fibrotic responses in HCSMCs via regulating Poldip2/mTOR signaling pathway.