title: Direct cell-cell interaction of cardiomyocytes is key for bone marrow stromal cells to go into cardiac lineage in vitro.
abstract: OBJECTIVE
  Cardiac environmental factors are thought to be powerful inducers in cardiomyogenic differentiation. In this study we simulated the cardiac environment using coculture and evaluated the cardiomyogenic differentiation in bone marrow stromal cells.
  
  
  METHODS
  In group 1 only bone marrow stromal cells derived from transgenic mice expressing green fluorescent protein (GFP-BMCs) were cultured (n = 5). In group 2 cardiomyocytes from neonatal rats were grown on inserts, which we applied to culture dishes seeded with GFP-BMCs (n = 5). In group 3 GFP-BMCs were cocultured with cardiomyocytes on the same dishes (n = 5). We cultured these cells for 7 days and evaluated the synchronous contraction and the cardiomyogenic differentiation of GFP-BMCs by means of immunostaining.
  
  
  RESULTS
  In groups 1 and 2 GFP-BMCs protein did not show any myogenic phenotypes for 7 days. In contrast, in group 3 some GFP-BMCs were incorporated in parallel with cardiomyocytes and revealed myotube-like formation on day 1. On day 2, some GFP-BMCs started to contract synchronously with cardiomyocytes. Myosin heavy chain-positive GFP-BMCs were recognized in 2.49% +/- 0.87% of the total GFP-BMCs on day 5 (P <.0001). Cardiac-specific troponin I-positive GFP-BMCs were in 1.86% +/- 0.53% of the total cells on day 5 (P <.0001). Atrial natriuretic peptide was also seen in GFP-BMCs, and connexin 43 was detected between GFP-BMCs and cardiomyocytes.
  
  
  CONCLUSIONS
  Direct cell-cell interaction with cardiomyocytes was important for bone marrow stromal cells to differentiate into cardiomyocytes. This coculture was useful for simulating the cardiac environment in vitro for the research of cell transplantation in the heart.
authors.affiliation: Department of Pathology, National Cardiovascular Center, Osaka, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Fukuhara
authors.forename: Shinji
authors.initials: S
authors.lastname: Tomita
authors.forename: Seiji
authors.initials: S
authors.lastname: Yamashiro
authors.forename: Takayuki
authors.initials: T
authors.lastname: Morisaki
authors.forename: Chikao
authors.initials: C
authors.lastname: Yutani
authors.forename: Soichiro
authors.initials: S
authors.lastname: Kitamura
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nakatani
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology*; D002450:Cell Communication / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology*; D002478:Cells, Cultured; D007150:Immunohistochemistry; D051379:Mice; D008822:Mice, Transgenic; D009206:Myocardium / Q000166:cytology*; D051381:Rats; D017154:Stromal Cells / Q000166:cytology*