Study On Coculture Of Embryonic Cardiomyocytes And Embryonic Stem Cells Affect Intercellular Signaling By Connexin43

Background:Cardiovascular diseases is one of the most serious and life threatened diseases for human beings. Stem cell therapy for ischemic cardiomyopathy has been a hot research topic in recent years. A variety of stem cells or stem cell-derived cells can be used for transplantation as potential candidates. Despite improved cardiac function after transplantation, one of the major problems is still remained-the poor integration between host tissue and donor cells which can lead to serious post-transplantation arrhythmia and poor long-term outcome. Objective:To evaluate the cellular interaction between mES and mEVs, the formation and function of gap junction in mES-derived cardiomyocytes under cocultured conditions.Methods:In the present study, we cocultured murine embryonic stem cells (mES) with murine embryonic ventricular myocytes (mEVs) byhanging drop method and investigate the cellular morphology, spontaneous beating status by microscopeobservation; intercellular gap junctional communication by scrape loading dye transfer (SLDT); the related genes and protein expression by PCR and Western blot; and connexin location by immunofluorescence staining. Thereby to study the cellular interactions between mES and mEVs and the function of mES-derived cardiomyocytes.Results:We found that (1) whenmEVs are added to a culture system of embryonic stem cells, the number of spontaneously beating areas in embryonic bodies (EBs) increases at mid-developmentalstage;(2) mRNA level of cardiac marker cTNT shows no significant difference between coculture group and control group;(3) SLDT showsintercellular gap junction communication enhanced in coculture group;(4) Cx43expression upregulated at mid-developmental stage both at mRNA and total protein level;(5) and Cx43is distributed more orderly between cardiomyocytes in coculture group.Conclusions:Our findings suggest mES-derived cardiomyocytes are able to express more Cx43and form effective signaling pathwayswhen coculture with mEVs which is importantfor providing more functional grafts for cardiac stem cells therapy byimproving the integration between transplanted and host cells.