title: Epigenetic reprogramming of human embryonic stem cells into skeletal muscle cells and generation of contractile myospheres.
abstract: Direct generation of a homogeneous population of skeletal myoblasts from human embryonic stem cells (hESCs) and formation of three-dimensional contractile structures for disease modeling in vitro are current challenges in regenerative medicine. Previous studies reported on the generation of myoblasts from ESC-derived embryoid bodies (EB), but not from undifferentiated ESCs, indicating the requirement for mesodermal transition to promote skeletal myogenesis. Here, we show that selective absence of the SWI/SNF component BAF60C (encoded by SMARCD3) confers on hESCs resistance to MyoD-mediated activation of skeletal myogenesis. Forced expression of BAF60C enables MyoD to directly activate skeletal myogenesis in hESCs by instructing MyoD positioning and allowing chromatin remodeling at target genes. BAF60C/MyoD-expressing hESCs are epigenetically committed myogenic progenitors, which bypass the mesodermal requirement and, when cultured as floating clusters, give rise to contractile three-dimensional myospheres composed of skeletal myotubes. These results identify BAF60C as a key epigenetic determinant of hESC commitment to the myogenic lineage and establish the molecular basis for the generation of hESC-derived myospheres exploitable for "disease in a dish" models of muscular physiology and dysfunction.
authors.affiliation: Sanford-Burnham Institute for Medical Research, La Jolla, CA 92037, USA.
authors.forename: Sonia
authors.initials: S
authors.lastname: Albini
authors.forename: Paula
authors.initials: P
authors.lastname: Coutinho
authors.forename: Barbora
authors.initials: B
authors.lastname: Malecova
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Giordani
authors.forename: Alex
authors.initials: A
authors.lastname: Savchenko
authors.forename: Sonia Vanina
authors.initials: SV
authors.lastname: Forcales
authors.forename: Pier Lorenzo
authors.initials: PL
authors.lastname: Puri
mesh_terms: D002460:Cell Line; D019070:Cell Lineage; D065150:Cellular Reprogramming; D042002:Chromatin Assembly and Disassembly; D002868:Chromosomal Proteins, Non-Histone; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism*; D044127:Epigenesis, Genetic; D006801:Humans; D008648:Mesoderm / Q000166:cytology; D009119:Muscle Contraction; D024510:Muscle Development / Q000235:genetics; D018485:Muscle Fibers, Skeletal / Q000166:cytology* / Q000378:metabolism / Q000502:physiology; D017570:MyoD Protein / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D017570:MyoD Protein; C057363:MyoD1 myogenic differentiation protein; C491649:SMARCD3 protein, human; D014157:Transcription Factors