title: Cell-to-cell contact induces mesenchymal stem cell to differentiate into cardiomyocyte and smooth muscle cell.
abstract: BACKGROUND
  Recent evidences have suggested that stem cell can differentiate into cardiomyocyte and smooth muscle cell (SMC) in vivo or in vitro. But the mechanism on how stem cell differentiates is still unknown. We investigated whether intercellular interaction or soluble chemical factors would induce mesenchymal stem cells (MSCs) to acquire the phenotypical characteristics of cardiomyocytes or SMC.
  
  
  METHODS
  MSCs were isolated from rat bone marrow with density gradient centrifugation and amplified in vitro. Flow cytometry was used to monitor the expression of surface antigen profile. After labeled by GFP (green fluorescent protein) transfection, rat MSCs were used to culture with adult rat cardiomyocytes and rat aortic SMCs in direct co-culture, indirect co-culture and conditioned culture, respectively. One week later, immunofluorescence staining against alpha-actin, desmin, and cardiac troponin T (cTnT) for cardiomyocyte, smooth muscle calponin and SM-alpha-actin for SMC were performed.
  
  
  RESULTS
  Immunofluorescence staining was positive against alpha-actin, desmin, and cTnT on MSCs in co-culture group with adult cardiomyocytes, positive against smooth muscle calponin and SM-alpha-actin on MSCs in co-culture group with SMCs. In contrast, no alpha-actin, desmin, and cTnT expression was observed in the indirect co-culture group and conditioned culture group; no smooth muscle calponin and SM-alpha-actin in the indirect co-culture group and conditioned culture group.
  
  
  CONCLUSIONS
  Direct cell-to-cell contact between MSC and adult cardiomyocyte or SMC, but not the soluble signaling molecules is obligatory in the differentiation of MSC into cardiomyocytes or SMC.
authors.affiliation: Department of Cardiovascular Medicine, First Hospital of Xi 'an Jiaotong University, Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University, Ministry of Education, No. 1 Jiankang Road, Xi'an, Shaanxi 710061, PR China.
authors.forename: Tingzhong
authors.initials: T
authors.lastname: Wang
authors.forename: Zhengyun
authors.initials: Z
authors.lastname: Xu
authors.forename: Wenhui
authors.initials: W
authors.lastname: Jiang
authors.forename: Aiqun
authors.initials: A
authors.lastname: Ma
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D001011:Aorta / Q000166:cytology; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002450:Cell Communication; D002454:Cell Differentiation / Q000502:physiology*; D018920:Coculture Techniques; D003893:Desmin / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D007150:Immunohistochemistry; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D008840:Microfilament Proteins / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D032383:Myocytes, Cardiac / Q000166:cytology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D000096985:Calponins
chemical_list: D000199:Actins; D002135:Calcium-Binding Proteins; D003893:Desmin; D008840:Microfilament Proteins; D000096985:Calponins