title: Novel chemically defined approach to produce multipotent cells from terminally differentiated tissue syncytia.
abstract: In urodele amphibians, a critical step in limb regeneration is the cellularization and dedifferentiation of skeletal muscle. In contrast, mammalian skeletal muscle does not undergo this response to injury. We have developed a novel simple, stepwise chemical method to induce dedifferentiation and multipotency in mammalian skeletal muscle. Optimal muscle fiber cellularization was induced by the trisubstituted purine small molecule, myoseverin, compared to colchicine, nocodazole, or myoseverin B. The induction of a proliferative response in the cellulate was found to be a crucial step in the dedifferentiation process. This was achieved by down-regulation of the cyclin-dependent kinase inhibitor, p21 (CDKN 1A, CIP1). p21 was found to be a key regulator of this process, because down-regulation of the cyclin-dependent kinase inhibitors p27 (CDKN1B/KIP1) or p57 (CDKN1C/KIP2) or the tumor suppressor p53 (TP53/LFS1) failed to induce proliferation and subsequent dedifferentiation. Treatment with the small molecule reversine (2-(4-morpholinoanilino)-6-cyclohexylaminopurine) during this proliferative "window" induced the muscle cellulate to differentiate into non-muscle cell types. This lineage switching was assessed using a relatively stringent approach, based on comparative functional and phenotypic assays of cell-type specific properties. This showed that our chemical method allowed the derivation of adipogenic and osteogenic cells that possessed a degree of functionality. This is the first demonstration that mammalian muscle culture can be induced to undergo cellularization, proliferation, and dedifferentiation, which is grossly similar to the key early steps in urodele limb regeneration. These results, based solely on the use of simple chemical approaches, have implications for both regenerative medicine and stem cell biology.
authors.affiliation: Small Molecule Regulators and Biosystems Laboratory, School of Life Sciences, Gwangju Institute of Science and Technology, 1 Oryong-Dong, Buk-Gu, Gwangju, Republic of Korea.
authors.forename: Da-Woon
authors.initials: DW
authors.lastname: Jung
authors.forename: Darren R
authors.initials: DR
authors.lastname: Williams
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000187:drug effects; D054337:Cell Dedifferentiation / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D003470:Culture Media / Q000737:chemistry / Q000494:pharmacology*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000037:antagonists & inhibitors / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects; D015726:Giant Cells / Q000166:cytology* / Q000187:drug effects*; D051379:Mice; D015394:Molecular Structure; D009025:Morpholines / Q000737:chemistry / Q000494:pharmacology*; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000187:drug effects; D011687:Purines / Q000737:chemistry / Q000494:pharmacology*; D054852:Small Molecule Libraries; D013329:Structure-Activity Relationship
chemical_list: D003470:Culture Media; D050759:Cyclin-Dependent Kinase Inhibitor p21; D009025:Morpholines; D011687:Purines; D054852:Small Molecule Libraries; C484369:2-(4-morpholinoanilino)-6-cyclohexylaminopurine