title: Inhibition of Drp1-dependent mitochondrial division impairs myogenic differentiation.
abstract: Mitochondria are dynamic organelles forming a tubular network that is continuously fusing and dividing to control their morphology and functions. Recent literature has shed new light on a potential link between the dynamic behavior of mitochondria and muscle development. In this study, we investigate the role of mitochondrial fission factor dynamin-related protein 1 (Drp1) in myogenic differentiation. We found that differentiation of C2C12 myoblasts induced by serum starvation was accompanied by a gradual increase in Drp1 protein expression (to ∼350% up to 3 days) and a fast reduction of Drp1 phosphorylation at Ser-637 (to ∼30%) resulting in translocation of Drp1 protein from the cytosol to mitochondria. During differentiation, treatment of myoblasts with mitochondrial division inhibitor (mdivi-1), a specific inhibitor of Drp1 GTPase activity, caused extensive formation of elongated mitochondria, which coincided with increased apoptosis evidenced by both enhanced caspase-3 activity and increased number of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive cells. Furthermore, the mdivi-1-treated myotubes (day 3 in differentiation media) showed a reduction in mitochondrial DNA content, mitochondrial mass, and membrane potential in a dose-dependent manner indicating defects in mitochondrial biogenesis during myogenic differentiation. Most interestingly, mdivi-1 treatment significantly suppressed myotube formation in both C2C12 cells and primary myoblasts. Likewise, stable overexpression of a dominant negative mutant Drp1 (K38A) dramatically reduced myogenic differentiation. These data suggest that Drp-1-dependent mitochondrial division is a necessary step for successful myogenic differentiation, and perturbation of mitochondrial dynamics hinders normal mitochondrial adaptations during muscle development. Therefore, in the present study, we report a novel physiological role of mitochondrial dynamics in myogenic differentiation.
authors.affiliation: Department of Kinesiology, College of Health Professions and Social Work, Temple University, Philadelphia, Pennsylvania;
authors.forename: Boa
authors.initials: B
authors.lastname: Kim
authors.forename: Ji-Seok
authors.initials: JS
authors.lastname: Kim
authors.forename: Yisang
authors.initials: Y
authors.lastname: Yoon
authors.forename: Mayra C
authors.initials: MC
authors.lastname: Santiago
authors.forename: Michael D
authors.initials: MD
authors.lastname: Brown
authors.forename: Joon-Young
authors.initials: JY
authors.lastname: Park
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D053148:Caspase 3 / Q000378:metabolism; D002460:Cell Line; D064550:Death-Associated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects / Q000502:physiology; D051379:Mice; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D063154:Mitochondrial Dynamics / Q000187:drug effects / Q000502:physiology*; D024510:Muscle Development / Q000187:drug effects / Q000502:physiology*; D032446:Myoblasts / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D052999:Quinazolinones / Q000494:pharmacology
chemical_list: C549041:3-(2,4-dichloro-5-methoxyphenyl)-2-sulfanyl-4(3H)-quinazolinone; D052999:Quinazolinones; D064550:Death-Associated Protein Kinases; D053148:Caspase 3
keywords: dynamin-related protein 1; mdivi-1; mitochondrial dynamics; myogenesis