Nitric oxide inhibition of Drp1-mediated mitochondrial fission is critical for myogenic differentiation

Silvia Brunelli (1) , Clara de Palma (1) , Sestina Falcone (1) , Serena Pisoni (1) , Sara Cipolat (1) , Chris Panzeri (1) , Addolorata Pisconti (1) , Raffaele Allevi (1) , Maria Teresa Bassi (1) , Giulio Cossu (1) , Tullio Pozzan (1) , Salvador Moncada (1) , Luca Scorrano (1) , Emilio Clementi (1) , Sarah Pambianco (1)

1 Division of regenerative Medicine

During myogenic differentiation the short mitochondria of myoblasts change into the extensively elongated network observed in myotubes. The functional relevance and the molecular mechanisms driving the formation of this mitochondrial network are unknown. We now show that mitochondrial elongation is required for myogenesis to occur and that this event depends on the cellular generation of nitric oxide (NO). Inhibition of NO synthesis in myogenic precursor cells leads to inhibition of mitochondrial elongation and of myogenic differentiation. This is due to the enhanced activity, translocation and docking to mitochondria of the pro-fission GTPase dynamin-related protein1 (Drp1), leading also to a latent mitochondrial dysfunction that increased sensitivity to apoptotic stimuli. These effects of inhibition of NO were not observed in myogenic precursor cells containing a dominant-negative form of Drp1. Both the NO-dependent repression of Drp1 action and the maintenance of mitochondrial integrity and function were mediated via the soluble guanylate cyclase. These data uncover a novel level of regulation of differentiation linking mitochondrial morphology and function to myogenic differentiation.

Mots clés: Nitric oxide; mitochondrial fission; Drp1; myogenesis

Silvia Brunelli, Clara de Palma, Sestina Falcone, Serena Pisoni, Sara Cipolat, et al.. Nitric oxide inhibition of Drp1-mediated mitochondrial fission is critical for myogenic differentiation. Cell Death and Differentiation, 2010, ⟨10.1038/cdd.2010.48⟩. ⟨hal-00535922⟩