Formation of Intercellular Junction between Cardiomyocyte and H9c2 Cell Line in Co-Culture

Park, Jeong Hyun; Kang, Han Sol; Park, Min Cheol; Kim, Dae Joong; Hahn, Jang Hee; Sung, Hoon Ki; Kim, Joo Young; Song, In Hwan; Sung, Eon Gi; Lee, Yung Chang

Abstract

Recently, new treatments for human heart disease such as ischemia, infarction, cardiomyopathy, coronary heart disease have been developed. transplantation various kinds of cells from skeletal muscle, endothelium, mesenchyme, hemopoietic tissue to injured area after infarction were challenged. It's so called 'Cell Transplantation'. This therapeutic strategy already adopted and got a good result in clinical trial. But several limitations are still remained, including ethics, donor cell numbers, side effects, therapeutic efficiency. In this research, we investigated the formation of intercellular junction and synchronous contraction between cardiomyocyte and H9c2 cell line in co-culture to establish experimental model in vitro for cell transplantation. For this purpose, two kinds of cells, primary cultured cardiomyocyte and H9c2 (cardiomyoblast cell line) were used. Cultured cardiomyocytes had repetitive contraction-relaxation pattern along longitudinal axis both in single and coculture. But their contractions were slower, less regular, less strong in co-culture than in cardiomyocyte culture only. H9c2 cells did not contracted actively themselves, but moved toward cardiomyocyte passively coincided with contraction. In contact region between two kinds of cells, there was no signal after immunocytochemical staining labeled with connexin43 (gap junction), desmoplakin (desmosome), N-cadherin (adherent junction) even though they had membrane contact. Moreover, F-actin and striation were less developed. These results suggested that co-culture system interfere with remodelling of contractile apparatus, intercellular junction formation as well as contraction-relaxation. Furthermore cardiomyocyte could not induce H9c2 cells differentiation into cardiomyocyte. Therefore, much more research would be essential for clinical application of cell transplantation and this study would be the basic source for further study of new therapy of myocardial disease and building up in vitro model.