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Three-Dimensional Mitochondria Reconstructions of Murine Cardiac Muscle Changes in Size Across Aging
Journal article   Open access   Peer reviewed

Three-Dimensional Mitochondria Reconstructions of Murine Cardiac Muscle Changes in Size Across Aging

Zer Vue, Kit Neikirk, Larry Vang, Edgar Garza-Lopez, Trace A. Christensen, Jianqiang Shao, Jacob Lam, Heather K. Beasley, Andrea G. Marshall, Amber Crabtree, …
American journal of physiology. Heart and circulatory physiology, Vol.325(5), pp.H965-H982
11/01/2023
DOI: 10.1152/ajpheart.00202.2023
PMCID: PMC10977873
PMID: 37624101
url
https://doi.org/10.1152/ajpheart.00202.2023View
Published (Version of record) Open Access

Abstract

With sparse treatment options, cardiac disease remains a significant cause of death among humans. As a person ages, mitochondria break down and the heart becomes less efficient. Heart failure is linked to many mitochondria-associated processes, including endoplasmic reticulum stress, mitochondrial bioenergetics, insulin signaling, autophagy, and oxidative stress. The roles of key mitochondrial complexes that dictate the ultrastructure, such as the mitochondrial contact site and cristae organizing system (MICOS), in aging cardiac muscle are poorly understood. To better understand the cause of age-related alteration in mitochondrial structure in cardiac muscle, we used transmission electron microscopy (TEM) and serial block facing-scanning electron microscopy (SBF-SEM) to quantitatively analyze the 3D networks in cardiac muscle samples of male mice at aging intervals of 3 months, 1 year, and 2 years. Here, we present the loss of cristae morphology, the inner folds of the mitochondria, across age. In conjunction with this, the 3D volume of mitochondria decreased. These findings mimicked observed phenotypes in murine cardiac fibroblasts with CRISPR/Cas9 knockout of Mitofilin, Chchd3, Chchd6 (some members of the MICOS complex), and Opa1, which showed poorer oxidative consumption rate and mitochondria with decreased mitochondrial length and volume. In combination, these data show the need to explore if loss of the MICOS complex in the heart may be involved in age-associated mitochondrial and cristae structural changes.
Aging cardiac muscle mitochondria MICOS serial block-face SEM three-dimensional morphometry

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