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.

Mitochondrial Fission and Fusion Factors Reciprocally Orchestrate Mitophagic Culling in Mouse Hearts and Cultured Fibroblasts

“…By contrast, Mfn1/Mfn2 DKO mitochondria were smaller and exhibited abnormal cristae structures (Figures 2b). Consistent with prior observations (Caffin et al, 2013; Kim, 2013; Papanicolaou et al, 2012), interruption of either mitochondrial fission or fusion was associated with depressed expression of mitochondrial biogenesis genes (Supplemental Figure 3a, 3b). …”

“…While the specific processes by which mitochondria communicate with the nucleus to activate biogenic gene expression have proven elusive, our results and prior studies are noteworthy because they show that an intact fission-fusion cycle is important for normal biogenesis (Caffin et al, 2013; Kim, 2013; Papanicolaou et al, 2012). This is consistent with biogenesis functioning as a pipeline for replacement components to be incorporated into pre-existing mitochondria as part of the normal renewal mechanism (as when the healthy daughter organelle of a fission event is re-integrating into the generally healthy mitochondrial pool), rather than as a means by which mitochondria are generated de-novo.…”

O-GlcNAcase deficiency suppresses skeletal myogenesis and insulin sensitivity in mice through the modulation of mitochondrial homeostasis

“…OGA deficiency impairs mitochondrial function during C2C12 differentiation Abnormal mitochondria could contribute to an abnormality in myogenesis [32]. Although no significant change in total protein O-GlcNAcylation was observed after OGA knockdown (Fig.…”

Connecting Mitochondria, Metabolism, and Stem Cell Fate

“…Furthermore, tight control of DRP1 levels and/or activity, possibly regulated by different post-translational modifications, might underlie these observations. Beyond its involvement in pluripotency, DRP1-mediated fission is required for the terminal differentiation of mESCs in neuronal lineages [58] as well as for the myogenic differentiation of myoblasts [61].…”