Expression of mitochondrial oxidative stress response genes in muscle is associated with mitochondrial respiration, physical performance, and muscle mass in the Study of Muscle, Mobility and Aging (SOMMA)

The cellular bases of mobility from the Study of Muscle, Mobility and Aging (SOMMA)

Findings from the Study of Muscle, Mobility and Aging (SOMMA) in this issue of Aging Cell show that several biological pathways in skeletal muscle cells play an important role in determining mobility in older adults. These are based on assays in skeletal muscle biopsies obtained from participants, aged 70 years and older in SOMMA tested for association with assessments related to mobility, including muscle mass, strength, power, cardiopulmonary fitness, and 400 m walking speed. The papers show that, using mass spectrometry, oxidative modifications of proteins essential to myocellular function are associated with poorer mobility. Using RNA-seq to quantify gene expression, lower levels of expression of antioxidant enzymes located in mitochondria, autophagy, patterns of expression of genes involved in autophagy, and higher levels of RNA transcripts that increase with denervation were associated with poorer performance on tests of mobility. These results extend previous research from the Baltimore Longitudinal Study of Aging and recent studies from SOMMA showing the importance of mitochondrial energetics in mobility. Together, these findings are painting a picture of how fundamental cellular processes influence the loss of mobility with aging. They may also be a window on aging in other cells, tissues, and systems. The data collected in SOMMA are publicly available and SOMMA welcomes collaborations with scientists who are interested in research about human aging.

Autophagy gene expression in skeletal muscle of older individuals is associated with physical performance, muscle volume and mitochondrial function in the study of muscle, mobility and aging (SOMMA)

Autophagy is essential for proteostasis, energetic balance, and cell defense and is a key pathway in aging. Identifying associations between autophagy gene expression patterns in skeletal muscle and physical performance outcomes would further our knowledge of mechanisms related with proteostasis and healthy aging. Muscle biopsies were obtained from participants in the Study of Muscle, Mobility, and Aging (SOMMA). For 575 participants, RNA was sequenced and expression of 281 genes related to autophagy regulation, mitophagy, and mTOR/upstream pathways was determined. Associations between gene expression and outcomes including mitochondrial respiration in muscle fiber bundles (MAX OXPHOS), physical performance (VO2 peak, 400 m walking speed, and leg power), and thigh muscle volume, were determined using negative binomial regression models. For autophagy, key transcriptional regulators including TFE3 and NFKB-related genes (RELA, RELB, and NFKB1) were negatively associated with outcomes. On the contrary, regulators of oxidative metabolism that also promote overall autophagy, mitophagy, and pexophagy (PPARGC1A, PPARA, and EPAS1) were positively associated with multiple outcomes. In line with this, several mitophagy, fusion, and fission-related genes (NIPSNAP2, DNM1L, and OPA1) were also positively associated with outcomes. For mTOR pathway and related genes, expression of WDR59 and WDR24, both subunits of GATOR2 complex (an indirect inhibitor of mTORC1), and PRKAG3, which is a regulatory subunit of AMPK, were negatively correlated with multiple outcomes. Our study identifies autophagy and selective autophagy such as mitophagy gene expression patterns in human skeletal muscle related to physical performance, muscle volume, and mitochondrial function in older persons which may lead to target identification to preserve mobility and independence.

Effects of exercise, physical activity, and sports on physical fitness in adults with Down syndrome: A systematic review

This systematic review aimed to analyze the effects of exercise, physical activity, and sports on physical fitness in adults with Down syndrome (DS). A literature search was conducted across four databases EBSCO, Scopus, Web of Science, and PubMed. The PRISMA guidelines were followed. The PEDro scale and the Cochrane risk of bias tool were used to assess the quality and risk of the studies, respectively. The protocol was registered in PROSPERO (code: CRD42023449627). Of the 423 records initially found, 13 were finally included in the systematic review, in which 349 adults with DS participated. 92% of the articles declared at least one significant difference post-intervention. The available evidence indicates that exercise, physical activity, and sports have a positive effect on some variables of physical fitness, especially strength, balance, body composition, cardiorespiratory fitness, flexibility, and functional capacity. Furthermore, it should be considered as an additional treatment or complementary therapy to improve the functionality and quality of life of adults with DS.