title: Cholesterol depletion by methyl-β-cyclodextrin enhances cell proliferation and increases the number of desmin-positive cells in myoblast cultures.
abstract: Skeletal myogenesis comprises myoblast replication and differentiation into striated multinucleated myotubes. Agents that interfere with myoblast replication are important tools for the understanding of myogenesis. Recently, we showed that cholesterol depletion by methyl-β-cyclodextrin (MCD) enhances the differentiation step in chick-cultured myogenic cells, involving the activation of the Wnt/β-catenin signaling pathway. However, the effects of cholesterol depletion on myoblast replication have not been carefully studied. Here we show that MCD treatment increases cell proliferation in primary chick myogenic cell cultures. Treatment of myogenic cells with the anti-mitotic reagent cytosine arabinoside, immediately following cholesterol depletion, blocks the MCD-induced effects on proliferation. Cholesterol depletion induced an increase in the number of desmin-positive mononucleated cells, and an increase in desmin expression. MCD induces an increase in the expression of the cell cycle regulator p53 and the master switch gene MyoD1. Treatment with BIO, a specific inhibitor of GSK3β, induced effects similar to MCD on cell proliferation; while treatment with Dkk1, a specific inhibitor of the Wnt/β-catenin pathway, neutralized the effects of MCD. These findings indicate that rapid changes in the cholesterol content in cell membranes of myoblasts can induce cell proliferation, possibly by the activation of the Wnt/β-catenin signaling pathway.
authors.affiliation: Laboratório de Diferenciação Muscular e Citoesqueleto, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Brazil.
authors.forename: Débora M
authors.initials: DM
authors.lastname: Portilho
authors.forename: Carolina P
authors.initials: CP
authors.lastname: Soares
authors.forename: Alexandre
authors.initials: A
authors.lastname: Morrot
authors.forename: Leandro S
authors.initials: LS
authors.lastname: Thiago
authors.forename: Gillian
authors.initials: G
authors.lastname: Butler-Browne
authors.forename: Wilson
authors.initials: W
authors.lastname: Savino
authors.forename: Manoel L
authors.initials: ML
authors.lastname: Costa
authors.forename: Cláudia
authors.initials: C
authors.lastname: Mermelstein
mesh_terms: D000818:Animals; D001973:Bromodeoxyuridine / Q000378:metabolism; D002452:Cell Count; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002642:Chick Embryo; D002784:Cholesterol / Q000172:deficiency*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D003893:Desmin / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D024510:Muscle Development / Q000187:drug effects; D017570:MyoD Protein / Q000378:metabolism; D032446:Myoblasts / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D009928:Organ Specificity; D015398:Signal Transduction / Q000187:drug effects; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D051153:Wnt Proteins / Q000378:metabolism; D047392:beta-Cyclodextrins / Q000494:pharmacology*
chemical_list: D050759:Cyclin-Dependent Kinase Inhibitor p21; D003893:Desmin; D017570:MyoD Protein; D016159:Tumor Suppressor Protein p53; D051153:Wnt Proteins; D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin; D002784:Cholesterol; D001973:Bromodeoxyuridine