title: A novel in vitro system for studying cardiomyocyte differentiation with medaka embryonic cells.
abstract: Our studies revealed that dissociated cells from medaka (the fresh-water fish, Oryzias latipes ) blastula-stage embryos differentiate into many rhythmically contracting cells when incubated with a conditioned medium from a cell line. Analyses of these cells by immunostaining, electron microscopy, expression of marker genes, action potential recordings and pharmacological responses all showed the characteristics of myocardial cells. We succeeded in purifying the cardiac cell-inducing factor from the conditioned medium by 523,100-fold with 8% recovery of the protein. Analysis of its amino-acid sequence by mass spectrometry revealed the factor to be medaka activin A2 (homodimer of inhibin betaA2 subunit). Recombinant human activin A showed the same cardiac cell-inducing activity toward medaka embryonic cells. Our results demonstrate that activin A is a potent factor for medaka myocardial cell differentiation. This culture method should provide a novel and simple experimental system to study cardiomyocyte differentiation in vitro.
authors.affiliation: Department of Biological Science and Technology, Tokai University, Numazu 410-0395, Japan. hyodo@tokai.ac.jp
authors.forename: Masao
authors.initials: M
authors.lastname: Hyodo
authors.forename: Shinji
authors.initials: S
authors.lastname: Makino
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Awaji
authors.forename: Yohei
authors.initials: Y
authors.lastname: Sakurada
authors.forename: Tomoichi
authors.initials: T
authors.lastname: Ohkubo
authors.forename: Mitsushige
authors.initials: M
authors.lastname: Murata
authors.forename: Keiichi
authors.initials: K
authors.lastname: Fukuda
authors.forename: Michio
authors.initials: M
authors.lastname: Tsuda
mesh_terms: D028341:Activins / Q000494:pharmacology; D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D006801:Humans; D032383:Myocytes, Cardiac / Q000166:cytology*; D009990:Oryzias / Q000196:embryology* / Q000378:metabolism
chemical_list: C422405:activin A; D028341:Activins