Paracrine effect of bone marrow mesenchymal stem cells on proliferation, apoptosis, and alpha-actin-2 expression in hepatic stellate cells.
We investigated the paracrine effects of bone marrow mesenchymal stem cells (BMSCs) on the proliferation, apoptosis, and alpha-actin-2 (ACTA2) expression of hepatic stellate cells (HSCs), and explored the possible mechanisms of hepatocyte growth factor (HGF). We established a co-culture system by culturing BMSCs on the upper layer and HSCs on the lower layer of a 6-well Transwell plate. Normal HSCs were cultured alone as a control. Cell apoptosis was determined by flow cytometry. We detected the expression of ACTA2 mRNA and ACTA2 protein in HSC using quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blotting, respectively. ACTA2 in HSCs was detected by fluorescent staining, and HGF in the co-culture supernatant was detected by enzyme-linked immunosorbent assay (ELISA). The apoptotic rate of HSCs in the experiment group was 2.6 times that in the control group (P < 0.05). The expression levels of ACTA2 mRNA and ACTA2 protein were significantly inhibited in HSCs compared with the control group (P < 0.05). HGF concentration in the co-culture supernatant was 0.43 ± 0.47 mM in the experimental group, which was significantly higher than in the control group (0.16 ± 0.43 mM) (P < 0.05). The paracrine effect of BMSCs, which was caused by the suppression of ACTA2 and HGF expression, induced HSC apoptosis.