Details

Autor(en) / Beteiligte

• Brand, Cameron S.
• Tan, Valerie P.
• Brown, Joan Heller
• Miyamoto, Shigeki

Titel

RhoA regulates Drp1 mediated mitochondrial fission through ROCK to protect cardiomyocytes

Ist Teil von

• Cellular signalling, 2018-10, Vol.50, p.48-57

Ort / Verlag

England: Elsevier Inc

Erscheinungsjahr

2018

Quelle

MEDLINE

Beschreibungen/Notizen

• Cardiac ischemia/reperfusion, loss of blood flow and its subsequent restoration, causes damage to the heart. Oxidative stress from ischemia/reperfusion leads to dysfunction and death of cardiomyocytes, increasing the risk of progression to heart failure. Alterations in mitochondrial dynamics, in particular mitochondrial fission, have been suggested to play a role in cardioprotection from oxidative stress. We tested the hypothesis that activation of RhoA regulates mitochondrial fission in cardiomyocytes. Our studies show that expression of constitutively active RhoA in cardiomyocytes increases phosphorylation of Dynamin-related protein 1 (Drp1) at serine-616, and leads to localization of Drp1 at mitochondria. Both responses are blocked by inhibition of Rho-associated Protein Kinase (ROCK). Endogenous RhoA activation by the GPCR agonist sphingosine-1-phosphate (S1P) also increases Drp1 phosphorylation and its mitochondrial translocation in a RhoA and ROCK dependent manner. Consistent with the role of mitochondrial Drp1 in fission, RhoA activation in cardiomyocytes leads to formation of smaller mitochondria and this is attenuated by inhibition of ROCK, by siRNA knockdown of Drp1 or by expression of a phosphorylation-deficient Drp1 S616A mutant. In addition, activation of RhoA prevents cell death in cardiomyocytes challenged by oxidative stress and this protection is blocked by siRNA knockdown of Drp1 or by Drp1 S616A expression. Taken together our findings demonstrate that RhoA activation can regulate Drp1 to induce mitochondrial fission and subsequent cellular protection, implicating regulation of fission as a novel mechanism contributing to RhoA-mediated cardioprotection. [Display omitted] •Activation of RhoA decreases mitochondrial size in cardiomyocytes through Drp1 dependent mitochondrial fission.•S1P and RhoA increase ROCK dependent phosphorylation of Drp1 at serine-616.•S1P and RhoA lead to mitochondrial Drp1 translocation in both cardiomyocytes and the heart.•Drp1 contributes to RhoA-mediated protection of cardiomyocytes from oxidative stress.