title: Embryonic stem cell differentiation: the role of extracellular factors.
abstract: Embryonic stem (ES) cells have the capacity to self renew and to differentiate into cellular derivatives of the endodermal, ectodermal, and mesodermal lineages. Therefore, ES cells have been used to analyse the effects of exogenous factors on the developmental pattern during in vitro differentiation. By using an in vitro loss-of-function approach based on beta1 integrin-deficient ES cells, it was found that integrin-dependent mechanisms are involved in the regulation of Wnt-1 and BMP-4 expression. Antagonistic effects of the signalling molecules Wnt-1 and BMP-4, morphogens involved in early differentiation events, have been observed in vivo and in vitro: BMP-4 acts as a potent mesoderm inducer, whereas Wnt-1 plays a critical role in the determination of neuroectoderm. Here, we summarise data of ES cell-derived cardiac, myogenic, and neuronal differentiation of wild type and beta1 integrin-deficient ES cells. We present evidence that the interaction of cells with the extracellular matrix via integrins determines the expression of the signalling molecules BMP-4 and Wnt-1, resulting in the activation of the mesodermal and neuroectodermal lineage, respectively. The results support the idea that the influence of the extracellular 'niche' on the developmental fate of pluripotent stem cells is determined not only by soluble factors, but also by the extracellular matrix.
authors.affiliation: In Vitro Differentiation Group, Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Czyz
authors.forename: A
authors.initials: A
authors.lastname: Wobus
mesh_terms: D000818:Animals; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000502:physiology; D002454:Cell Differentiation; D004622:Embryo, Mammalian / Q000166:cytology*; D018507:Gene Expression Regulation, Developmental; D006321:Heart / Q000196:embryology; D006801:Humans; D019012:Integrin beta1 / Q000502:physiology; D009474:Neurons / Q000502:physiology; D011518:Proto-Oncogene Proteins / Q000502:physiology; D013234:Stem Cells / Q000502:physiology*; D051153:Wnt Proteins; D051155:Wnt1 Protein; D029961:Zebrafish Proteins
chemical_list: C525809:BMP4 protein, human; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D019012:Integrin beta1; D011518:Proto-Oncogene Proteins; C495247:WNT1 protein, human; D051153:Wnt Proteins; D051155:Wnt1 Protein; D029961:Zebrafish Proteins; C525813:bmp4 protein, zebrafish