Low abundance of Mfn2 protein correlates with reduced mitochondria-SR juxtaposition and mitochondrial cristae density in human men skeletal muscle: Examining organelle measurements from TEM images.
FASEB J
; 35(4): e21553, 2021 04.
Article
em En
| MEDLINE
| ID: mdl-33749943
ABSTRACT
The role of mitofusin 2 (Mfn2) in the regulation of skeletal muscle (SM) mitochondria-sarcoplasmic (SR) juxtaposition, mitochondrial morphology, mitochondrial cristae density (MCD), and SM quality has not been studied in humans. In in vitro studies, whether Mfn2 increases or decreases mitochondria-SR juxtaposition remains controversial. Transmission electron microscopy (TEM) images are commonly used to measure the organelle juxtaposition, but the measurements are performed "by-hand," thus potentially leading to between-rater differences. The purposes of this study were to (1) examine the repeatability and reproducibility of mitochondrial-SR juxtaposition measurement from TEM images of human SM between three raters with different experience and (2) compare the mitochondrial-SR juxtaposition, mitochondrial morphology, MCD (stereological-method), and SM quality (cross-sectional area [CSA] and the maximum voluntary contraction [MVC]) between subjects with high abundance (Mfn2-HA; n = 6) and low abundance (Mfn2-LA; n = 6) of Mfn2 protein. The mitochondria-SR juxtaposition had moderate repeatability and reproducibility, with the most experienced raters showing the best values. There were no differences between Mfn2-HA and Mfn2-LA groups in mitochondrial size, distance from mitochondria to SR, CSA, or MVC. Nevertheless, the Mfn2-LA group showed lower mitochondria-SR interaction, MCD, and VO2max . In conclusion, mitochondrial-SR juxtaposition measurement depends on the experience of the rater, and Mfn2 protein seems to play a role in the metabolic control of human men SM, by regulating the mitochondria-SR interaction.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Músculo Esquelético
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Proteínas Mitocondriais
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Membranas Mitocondriais
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GTP Fosfo-Hidrolases
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Mitocôndrias
Limite:
Humans
Idioma:
En
Ano de publicação:
2021
Tipo de documento:
Article