Regulation of Mitochondrial Dynamics and Cell Fate

Abstract

Circulation Journal Official Journal of the Japanese Circulation Society http://www. j-circ.or.jp ollowing the discovery of the mitochondrion in the mid-1800 s, there has been considerable interest over the past 100 years of biological research to understand how this remarkable organelle controls vital cellular processes such as energy metabolism, proliferation and cell death. Although mitochondria were first established as the "power house" of the cell, it was not until the mid-1970 s that they were appreciated for having cellular functions beyond their original ascribed role in energy production. 1 The concept that mitochondria contain the necessary signaling factors for initiating and executing programmed cell death was considered a major paradigm shift regarding their importance in regulating cell fate. Indeed, several lines of investigation have proposed the mitochondrion as a central gateway for integrating signals for apoptosis, necrosis and autophagy. 2 Though mitochondria were initially viewed as static organelles, it is now well appreciated that they are dynamic structures that move freely throughout the cell via dynamin motor GTPases. 3-5 The discovery of the mitochondrial "shaping" proteins, the "mitofusins", further revolutionized our understanding of mitochondrial plasticity in normal and disease states (reviewed by McBride and Scorrano 4 , Westermann 6 ). These proteins enable mitochondria to rapidly change morphology and complex networks within the cell through fusion and fission processes. In fact, defects in mitochondrial fission/ fusion events have been identified in a number of human pathologies. It is not surprising that inborn genetic errors resulting in abnormal mitochondrial dynamics have been linked to cancer, cardiovascular disease, and neurodegenerative diseases. 4 In the context of the adult heart, the functional loss of cardiac myocytes by mitochondrial-driven programmed cell death (apoptosis or necrosis) is postulated as an underlying cause of ventricular remodeling and heart failure. 7 More recent studies have implicated mitochondrial fission/fusion events in autophagy/mitophagy during ischemic injury. 8, 9 In this review, we will discuss the importance of mitochondrial dynamics and fusion/fission processes under normal and stress conditions and the effect on cardiac function in particular. Mitochondrial DynamicsMitochondria are highly dynamic and plastic structures that are continually changing morphology. 10 Multiple proteins located on the outer (OMM) and inner (IMM) mitochondrial membranes have been linked to mitochondrial fission/fusion. Fission proteins include the cytosolic GTPase Dynamin-related protein-1 (Drp1), 11 Fission-1 (Fis1), 12,13 Mitochondrial fission factor (Mff), 14 TBC1D15 15 and others, and the mitochondrial fusion proteins include the large GTPase mitofusins (Mfn1 and Mfn2) 16 localized on the OMM, as well as optic atrophy 1 (OPA1) 17 located on the IMM. The coordinated dynamic activation of these proteins during cell division and cell proliferation is respon...

DJ-1 protects the heart against ischemia–reperfusion injury by regulating mitochondrial fission

“…Another main finding of the current study relates to the ability of DJ-1 to regulate mitochondrial dynamics, a highly organized process by which mitochondria change size via fusion and fission [40]. Both processes are necessary for the maintenance of organelle fidelity and cell homeostasis [31], as a disruption in either results in abnormal mitochondrial function and cell death [40].…”

Ferulic acid attenuates brain microvascular endothelial cells damage caused by oxygen-glucose deprivation via punctate-mitochondria-dependent mitophagy

“…Mitochondria undergo rapid and extensive mitochondrial fission at an early stage of mitochondrial dysfunction (Dhingra and Kirshenbaum, 2014).…”

Mitochondrial fusion, fission, and mitochondrial toxicity

“…Transcriptional regulation is relatively poorly understood, and post-translational regulation is quite complex (Dhingra and Kirshenbaum 2014). Reported environmental regulation of mitochondrial fusion, fission and morphology are reviewed in Section 2.…”