title: In vitro differentiation of embryonic stem cells into cardiomyocytes or skeletal muscle cells is specifically modulated by retinoic acid.
abstract: Pluripotent embryonic stem cells (ES cells) differentiating via embryo-like aggregates (embryoid bodies) into derivatives of the primary germ layers were used as a model system to investigate the time- and concentration dependent effects of retinoic acid (RA) on the in vitro differentiation pattern. When ES cells, cultivated normally under conditions resulting in cardiomyocyte differentiation, were treated during the first 2 days of embryoid body formation with high RA concentrations (10-9to 10-7M) a strong inhibition of cardiogenesis was found. ES cells differentiating as embryoid bodies and treated with the same RA concentration between the 5th and 7th day resulted in a slight induction of cardiogenesis. In contrast, incubation of embryoid bodies with 10-8and 10-7M RA between the 2nd and 5th day of embryoid body development resulted in a total inhibition of cardiogenesis but in an induction of myogenesis. This was demonstrated by indirect immunofluorescence and, as shown by reverse transcription- polymerase chain reaction (RT-PCR), by the time- and concentration-dependent inhibition of transcription of cardiac-specific α- and β-cardiac myosin heavy chain (MHC) genes, and the induction of transcription of skeletal muscle-specific myogenin. In addition, using the whole-cell patch-clamp technique, these skeletal myocytes were functionally characterized by the expression of tissue-specific Ca2+channels and nicotinic cholinoceptors. In summary, a specific effect of RA on ES cell differentiation in the embryoid body resulting in a switch from cardiogenesis to myogenesis and an induction of neuronal cells was found.
authors.affiliation: Institut für Pflanzengenetik und Kulturpflanzenforschung, Corrensstrasse 3, D-06466, Gatersleben, Germany.
authors.forename: Anna M
authors.initials: AM
authors.lastname: Wobus
authors.affiliation: Institut für Pflanzengenetik und Kulturpflanzenforschung, Corrensstrasse 3, D-06466, Gatersleben, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Rohwedel
authors.affiliation: Institut für Pflanzengenetik und Kulturpflanzenforschung, Corrensstrasse 3, D-06466, Gatersleben, Germany.
authors.forename: Victor
authors.initials: V
authors.lastname: Maltsev
authors.affiliation: Institut für Pharmakologie der Freien Universität Berlin, D-14195, Berlin, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Hescheler
keywords: Cardiomyocytes; Differentiation; Mouse embryonic stem cells; Retinoic acid; Skeletal muscle cells