Resistance of Dynamin-related Protein 1 Oligomers to Disassembly Impairs Mitophagy, Resulting in Myocardial Inflammation and Heart Failure.

Abstract

We have reported previously that a missense mutation in the mitochondrial fission gene Dynamin-related protein 1 (Drp1) underlies the Python mouse model of monogenic dilated cardiomyopathy. The aim of this study was to investigate the consequences of the C452F mutation on Drp1 protein function and to define the cellular sequelae leading to heart failure in the Python monogenic dilated cardiomyopathy model. We found that the C452F mutation increased Drp1 GTPase activity. The mutation also conferred resistance to oligomer disassembly by guanine nucleotides and high ionic strength solutions. In a mouse embryonic fibroblast model, Drp1 C452F cells exhibited abnormal mitochondrial morphology and defective mitophagy. Mitochondria in C452F mouse embryonic fibroblasts were depolarized and had reduced calcium uptake with impaired ATP production by oxidative phosphorylation. In the Python heart, we found a corresponding progressive decline in oxidative phosphorylation with age and activation of sterile inflammation. As a corollary, enhancing autophagy by exposure to a prolonged low-protein diet improved cardiac function in Python mice. In conclusion, failure of Drp1 disassembly impairs mitophagy, leading to a downstream cascade of mitochondrial depolarization, aberrant calcium handling, impaired ATP synthesis, and activation of sterile myocardial inflammation, resulting in heart failure.

• Authors: Thomas J Cahill, Vincenzo Leo, Matthew Kelly, Alexander Stockenhuber, Nolan W Kennedy, Leyuan Bao, Grazia M Cereghetti, Andrew R Harper, Gabor Czibik, Chunyan Liao, Mohamed Bellahcene, Violetta Steeples, Safar Ghaffari, Arash Yavari, Alice Mayer, Joanna Poulton, David J P Ferguson, Luca Scorrano, Nishani T Hettiarachchi, Chris Peers, John Boyle, R Blake Hill, Alison Simmons, Hugh Watkins, T Neil Dear, Houman Ashrafian
• Journal: The Journal of biological chemistry (J Biol Chem) Vol. 290 Issue 43 Pg. 25907-19 (10 23 2015) ISSN: 1083-351X [Electronic] United States
• PMID: 26370078 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Chemical References

• Biopolymers
• Dnm1l protein, mouse
• Dynamins

Topics

• Animals
• Biopolymers (genetics, metabolism, physiology)
• Cells, Cultured
• Dynamins (genetics, metabolism, physiology)
• Heart Failure (etiology, physiopathology)
• Mice
• Mitophagy
• Mutation
• Myocarditis (etiology, physiopathology)
• Oxidative Phosphorylation