Cholesterol depletion by methyl-β-cyclodextrin enhances cell proliferation and increases the number of desmin-positive cells in myoblast cultures

• Published in: European journal of pharmacology 2012-11, Vol.694 (1-3), p.1-12
• Main Authors: Portilho, Débora M., Soares, Carolina P., Morrot, Alexandre, Thiago, Leandro S., Butler-Browne, Gillian, Savino, Wilson, Costa, Manoel L., Mermelstein, Cláudia
• Format: Article
• Language: English
• Subjects: Animals; beta-Cyclodextrins - pharmacology; Bromodeoxyuridine - metabolism; Cell Count; cell culture; cell cycle; cell membranes; cell proliferation; Cell Proliferation - drug effects; Cell replication; Cell Survival - drug effects; Chick Embryo; chicks; Cholesterol; Cholesterol - deficiency; Cyclin-Dependent Kinase Inhibitor p21 - metabolism; cytosine; Desmin; Desmin - metabolism; Gene Expression Regulation - drug effects; genes; Methyl-β-cyclodextrin; muscle development; Muscle Development - drug effects; Muscle differentiation; myoblasts; Myoblasts - cytology; Myoblasts - drug effects; Myoblasts - metabolism; MyoD Protein - metabolism; Myogenesis; Organ Specificity; pharmacology; signal transduction; Signal Transduction - drug effects; Tumor Suppressor Protein p53 - metabolism; Wnt Proteins - metabolism
• ISSN: 0014-2999; 1879-0712
• DOI: 10.1016/j.ejphar.2012.07.035

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.