Cardiac cell differentiation of mouse embryonic stem cells in the co-culture with fetal heart

Abstract

To investigate the effect of fetal cardiac cells on the differentiation of embryonic stem cells (ESCs) into cardiomyocytes, Mouse ESCs were co-cultured with heart cells prepared from fetus aged 11.5, 12.5, 13.5 or 14.5 days postcoitum (dpc). The fetal mouse heart was from ICR and 129 strains from which KH2 ES cell line was derived. In the present study, KH2 cells expressing EGFP directed by α-myosin heavy chain gene promoter were co-cultured with fetal heart isolated at different fetal stages. The cardiomyocytes derived from ESC in the co-culture could be identified by their EGFP expression. The EGFP expressing cells which were confirmed to be cardiomyocytes were measured as an indicator of cardiac cell differentiation of ESC. The fetal cardiac cells from 12.5 dpc were more effective in cardiac cell differentiation of ESC than the cells from fetus aged 11.5, 13.5 or 14.5 dpc. Fetal heart from 129 strain which is immunologically compatible with KH2 cells showed more strong cardiac cell differentiation induction activity compared with that from ICR mice. As the results, we demonstrated that fetal hearts at different developmental stages have different cardiac cell differentiation induction activity from ESC implying that fetal heart expresses cardiac cell differentiation induction factor(s).