title: Modulation of sarcomere organization during embryonic stem cell-derived cardiomyocyte differentiation.
abstract: Myofibrillogenesis - sarcomeres - mouse embryonic stem cells - cardiomyocytes - beta1 integrin Mouse embryonic stem (ES) cells, when cultivated as embryoid bodies, differentiate in vitro into cardiomyocytes of ventricle-, atrium- and pacemaker-like cell types characterized by developmentally controlled expression of cardiac-specific genes, structural proteins and ion channels. Using this model system, we show here, (I) that during cardiac myofibrillogenesis sarcomeric proteins are organized in a developmentally regulated manner following the order: titin (Z-disk), alpha-actinin, myomesin, titin (M-band), myosin heavy chain, alpha-actin, cardiac troponin T and M-protein, recapitulating the sarcomeric organization in the chicken embryonal heart in vivo. Our data support the view that the formation of I-Z-I complexes is developmentally delayed with respect to A-band assembly. We show (2) that the process of cardiogenic differentiation in vitro is influenced by medium components: Using a culture medium supplemented with glucose, amino acids, vitamins and selenium ions, we were able to increase the efficiency of cardiac differentiation of wild-type, as well as of beta1 integrin-deficient (beta1-/-) ES cells, and to improve the degree of organization of sarcomeric structures in wild-type and in beta1-/- cardiac cells. The data demonstrate the plasticity of cardiogenesis during the differentiation of wild-type and of genetically modified ES cells.
authors.affiliation: In Vitro Differentiation Group, IPK Gatersleben, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Guan
authors.forename: D O
authors.initials: DO
authors.lastname: Fürst
authors.forename: A M
authors.initials: AM
authors.lastname: Wobus
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D064211:Connectin; D018507:Gene Expression Regulation, Developmental; D006321:Heart / Q000196:embryology*; D019012:Integrin beta1 / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D009124:Muscle Proteins; D009194:Myeloma Proteins / Q000378:metabolism; D009206:Myocardium / Q000166:cytology* / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000032:analysis* / Q000235:genetics; D011494:Protein Kinases / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D012518:Sarcomeres / Q000378:metabolism*
chemical_list: D064211:Connectin; D019012:Integrin beta1; D009124:Muscle Proteins; D009194:Myeloma Proteins; D012333:RNA, Messenger; C085016:multiple myeloma M-proteins; D011494:Protein Kinases; D018995:Myosin Heavy Chains