Dysregulations of mitochondrial quality control and autophagic flux at an early age lead to progression of sarcopenia in SAMP8 mice

The senescence-accelerated mouse (SAM) prone 8 (SAMP8) has been demonstrated for muscular aging research including sarcopenia, but its underlying mechanisms remain scarce. Physiological indices and histology of skeletal muscle were analyzed in SAMP8 mice at different ages. SAMP8 mice exhibited typic...

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Published in:Biogerontology (Dordrecht) 2020-06, Vol.21 (3), p.367-380
Main Authors: Liu, Hung-Wen, Chang, Yun-Ching, Chan, Yin-Ching, Hu, Shu-Hui, Liu, Ming-Yi, Chang, Sue-Joan
Format: Article
Language:English
Subjects:
Aging
Biomedical and Life Sciences
Carbonyl compounds
Cell Biology
Developmental Biology
FOXO3 protein
Geriatrics/Gerontology
Inflammation
Interleukin 6
Leptin
Life Sciences
Mitochondria
Monocyte chemoattractant protein 1
Myostatin
Oxidative stress
Quality control
Research Article
Sarcopenia
Satellite cells
Senescence
Skeletal muscle
TOR protein
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Summary:The senescence-accelerated mouse (SAM) prone 8 (SAMP8) has been demonstrated for muscular aging research including sarcopenia, but its underlying mechanisms remain scarce. Physiological indices and histology of skeletal muscle were analyzed in SAMP8 mice at different ages. SAMP8 mice exhibited typical features of sarcopenia at 40 weeks of age and were more time-efficient than that at 88 weeks of age in bothSAM resistant 1 (SAMR1) and C57BL/6 mice. Increase in FoxO3a-mediated transcription of Atrogin-1 and MuRF1 and decrease in phosphorylated mTOR/P70 s6k were observed at week 40 in SAMP8 mice. High oxidative stress was observed from week 24 and persisted to week 40 in SAMP8 mice evidenced by overexpression of protein carbonyl groups and reduced activities of CAT, SOD, and GPx. Downregulation of genes involved in mitochondrial biogenesis ( PGC-1α , Nrf-1 , Tfam , Ndufs8 , and Cox5b ) and in mitochondrial dynamics fission ( Mfn2 and Opa1 ) from week 24 indicated dysregulation of mitochondrial quality control in SAMP8 mice. Impaired autophagic flux was observed in SAMP8 mice evidenced by elevated Atg13 and LC3-II accompanied with the accumulation of P62 and LAMP1. Increases in inflammatory factors (IL-6 and MCP-1), adipokines (leptin and resistin), and myostatin in serum at week 32 and decline in Pax7+ satellite cell resided next to muscle fibers at week 24 implied that muscle microenvironment contributed to the progression of sarcopenia in SAMP8 mice. Our data suggest that early alterations of mitochondrial quality control and autophagic flux worsen muscle microenvironment prior to the onset of sarcopenia.
ISSN:1389-5729
1573-6768
DOI:10.1007/s10522-020-09867-x