Serum response factor promotes differentiation of rat bone marrow mesenchymal stem cells into smooth muscle cells via histone acetylation

Abstract

Objective To explore the role and mechanism of serum response factor (SRF) in differentiation of rat bone marrow mesenchymal stem cells (MSCs) into bladder smooth muscle cells (SMCs). Methods Rat MSCs and SMCs were isolated respectively from the bone marrow and bladder of 4-week-old female SD rats by adherent method, and then co-cultured together in a Transwell chamber. After the MSCs were harvested at different time points, real-time PCR and immunofluorescense assay were used to detect the expression of SMCs specific marker genes in co-cultured MSCs. Furthermore, the enrichment of histone acetylation modification, histone deacetylase (HDAC) and SRF in the promoter of these genes were tested by chromatin immunoprecipitation assay (ChIP) q-PCR in co-cultured MSCs. Finally, ChIP-qPCR was used to compare the histone acetylation modification and SRF enrichment in sodium butyrate (NaB) pretreatment group with control cells. Results The expression levels of α-SMA, Calponin and SM-MHC were increased in MSCs co-cultured with SMCs. H3K9ace, H3ace and H4ace in the promoter of these genes were enriched (P<0.05), and then, HDAC1 and HDAC2 in the induced MSCs were correspondingly decreased significantly (P<0.05). The enrichment of SRF in the NaB pretreatment group shared the same increasing tendency with H3K9ace and H4ace. Conclusion SRF may bind to H3K9ace and H4ace, through the regulation of HDAC1 and HDAC2 to control the expression of SMCs specific genes, and thus promote the differentiation from MSCs to SMCs.

Keywords

• bone mesenchymal stem cells
• serum response factor
• differentiation
• histone acetylation
• sodium butyrate