title: C2C12 myoblast/osteoblast transdifferentiation steps enhanced by epigenetic inhibition of BMP2 endocytosis.
abstract: We investigated the modulation of critical transcriptional steps of C2C12 myoblast/osteoblast transdifferentiation triggered by the bone morphogenetic protein 2 (BMP2) signaling protein, in response to epigenetic inhibition of the endocytotic internalization of exogenous BMP2. BMP2 endocytosis was inhibited chemically with polyethylene glycol-50 (PEG-Chol) and cyclodextrin and mechanically by mild hyposmotic treatment. BMP2-dependent nuclear translocation of the mother against Dpp (Smad1) transcription factor was ten times faster if BMP2 endocytosis was inhibited. Smad1-dependent expression of the JunB gene, the first transcriptional step in myoblast dedifferentiation, was increased by a factor of three to four. JunB-dependent levels of myogenin repression, one of the critical markers of terminal myoblastic differentiation, was amplified by a factor of three. Smad1-dependent levels of alkaline phosphatase expression, one of the C2C12 osteoblast differentiation markers, were 3.5 to 5 times higher. The same behavior was observed for osteopontin, the other C2C12 osteoblast differentiation marker. These results suggest that the cell genome could "sense" tissue mechanical deformations by mechanical inhibition of signaling protein endocytosis, thereby translating mechanical strains into transcription events involved in cell differentiation.
authors.affiliation: Mechanics and Genetics of Developmental Embryogenesis Group, Unité Mixte de Recherche 168 Physico-Chimie Curie, Curie Institut, 75005 Paris, France.
authors.forename: Cyril
authors.initials: C
authors.lastname: Rauch
authors.forename: Anne-Christine
authors.initials: AC
authors.lastname: Brunet
authors.forename: Julie
authors.initials: J
authors.lastname: Deleule
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Farge
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D001692:Biological Transport / Q000502:physiology; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000378:metabolism* / Q000493:pharmacokinetics; D002454:Cell Differentiation / Q000502:physiology; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D002784:Cholesterol / Q000031:analogs & derivatives* / Q000494:pharmacology; D003505:Cyclodextrins / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000378:metabolism; D004705:Endocytosis / Q000502:physiology*; D015870:Gene Expression / Q000502:physiology; D007038:Hypotonic Solutions / Q000494:pharmacology; D051379:Mice; D009132:Muscles / Q000166:cytology* / Q000378:metabolism*; D018008:Myogenin / Q000037:antagonists & inhibitors; D010006:Osteoblasts / Q000166:cytology* / Q000378:metabolism*; D053495:Osteopontin; D011092:Polyethylene Glycols / Q000494:pharmacology; D016755:Proto-Oncogene Proteins c-jun / Q000235:genetics / Q000378:metabolism; D012795:Sialoglycoproteins / Q000378:metabolism; D051785:Smad Proteins; D051898:Smad1 Protein; D015534:Trans-Activators / Q000378:metabolism; D016212:Transforming Growth Factor beta
chemical_list: C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D003505:Cyclodextrins; D004268:DNA-Binding Proteins; D007038:Hypotonic Solutions; C503801:Myog protein, mouse; D018008:Myogenin; D016755:Proto-Oncogene Proteins c-jun; D012795:Sialoglycoproteins; D051785:Smad Proteins; D051898:Smad1 Protein; C497401:Smad1 protein, mouse; C506896:Spp1 protein, mouse; D015534:Trans-Activators; D016212:Transforming Growth Factor beta; C095164:poly(oxyethylene) cholesteryl ether; D053495:Osteopontin; D011092:Polyethylene Glycols; D002784:Cholesterol; D000469:Alkaline Phosphatase