Activation of mitophagy and proteasomal degradation confers resistance to developmental defects in postnatal skeletal muscle
Abstract Background Postnatal skeletal muscle development leads to increased muscle mass, strength, and mitochondrial function, but the role of mitochondrial remodeling during this period is unclear. This study investigates mitochondrial remodeling during postnatal muscle development and examines ho...
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2025-08-01
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| Online Access: | https://doi.org/10.1186/s12929-025-01153-7 |
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| author | Fasih A. Rahman Mackenzie Q. Graham Alex Truong Joe Quadrilatero |
| author_facet | Fasih A. Rahman Mackenzie Q. Graham Alex Truong Joe Quadrilatero |
| author_sort | Fasih A. Rahman |
| collection | DOAJ |
| description | Abstract Background Postnatal skeletal muscle development leads to increased muscle mass, strength, and mitochondrial function, but the role of mitochondrial remodeling during this period is unclear. This study investigates mitochondrial remodeling during postnatal muscle development and examines how constitutive autophagy deficiency impacts these processes. Methods We initially performed a broad RNA-Seq analysis using a publicly available GEO database of skeletal muscle from postnatal day 7 (P7) to postnatal day 112 (P112) to identify differentially expressed genes. This was followed by investigation of postnatal skeletal muscle development using the mitophagy report mouse line (mt-Kiema mice), as well as conditional skeletal muscle knockout (Atg7 f/f:Acta1−Cre) mice. Results Our study observed rapid growth of body and skeletal muscle mass, along with increased fiber cross-sectional area and grip strength. Mitochondrial maturation was indicated by enhanced maximal respiration, reduced electron leak, and elevated mitophagic flux, as well as increased mitochondrial localization of autophagy and mitophagy proteins. Anabolic signaling was also upregulated, coinciding with increased mitophagy and fusion signaling, and decreased biogenesis signaling. Despite the loss of mitophagic flux in skeletal muscle-specific Atg7 knockout mice, there were no changes in body or skeletal muscle mass; however, hypertrophy was observed in type IIX fibers. This lack of Atg7 and loss of mitophagy was associated with the activation of mitochondrial apoptotic signaling as well as ubiquitin–proteasome signaling, suggesting a shift in degradation mechanisms. Inhibition of the ubiquitin–proteasome system (UPS) in autophagy-deficient skeletal muscle led to significant atrophy, increased reactive oxygen species production, and mitochondrial apoptotic signaling. Conclusion These results highlight the role of mitophagy in postnatal skeletal muscle development and suggest that autophagy-deficiency triggers compensatory degradative pathways (i.e., UPS) to prevent mitochondrial apoptotic signaling and thus preserve skeletal muscle integrity in developing mice. |
| format | Article |
| id | doaj-art-cbe5abdeef6444499f3fd39efd94728d |
| institution | Kabale University |
| issn | 1423-0127 |
| language | English |
| publishDate | 2025-08-01 |
| publisher | BMC |
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| series | Journal of Biomedical Science |
| spelling | doaj-art-cbe5abdeef6444499f3fd39efd94728d2025-08-24T11:42:22ZengBMCJournal of Biomedical Science1423-01272025-08-0132111910.1186/s12929-025-01153-7Activation of mitophagy and proteasomal degradation confers resistance to developmental defects in postnatal skeletal muscleFasih A. Rahman0Mackenzie Q. Graham1Alex Truong2Joe Quadrilatero3Department of Kinesiology and Health Sciences, University of WaterlooDepartment of Kinesiology and Health Sciences, University of WaterlooDepartment of Kinesiology and Health Sciences, University of WaterlooDepartment of Kinesiology and Health Sciences, University of WaterlooAbstract Background Postnatal skeletal muscle development leads to increased muscle mass, strength, and mitochondrial function, but the role of mitochondrial remodeling during this period is unclear. This study investigates mitochondrial remodeling during postnatal muscle development and examines how constitutive autophagy deficiency impacts these processes. Methods We initially performed a broad RNA-Seq analysis using a publicly available GEO database of skeletal muscle from postnatal day 7 (P7) to postnatal day 112 (P112) to identify differentially expressed genes. This was followed by investigation of postnatal skeletal muscle development using the mitophagy report mouse line (mt-Kiema mice), as well as conditional skeletal muscle knockout (Atg7 f/f:Acta1−Cre) mice. Results Our study observed rapid growth of body and skeletal muscle mass, along with increased fiber cross-sectional area and grip strength. Mitochondrial maturation was indicated by enhanced maximal respiration, reduced electron leak, and elevated mitophagic flux, as well as increased mitochondrial localization of autophagy and mitophagy proteins. Anabolic signaling was also upregulated, coinciding with increased mitophagy and fusion signaling, and decreased biogenesis signaling. Despite the loss of mitophagic flux in skeletal muscle-specific Atg7 knockout mice, there were no changes in body or skeletal muscle mass; however, hypertrophy was observed in type IIX fibers. This lack of Atg7 and loss of mitophagy was associated with the activation of mitochondrial apoptotic signaling as well as ubiquitin–proteasome signaling, suggesting a shift in degradation mechanisms. Inhibition of the ubiquitin–proteasome system (UPS) in autophagy-deficient skeletal muscle led to significant atrophy, increased reactive oxygen species production, and mitochondrial apoptotic signaling. Conclusion These results highlight the role of mitophagy in postnatal skeletal muscle development and suggest that autophagy-deficiency triggers compensatory degradative pathways (i.e., UPS) to prevent mitochondrial apoptotic signaling and thus preserve skeletal muscle integrity in developing mice.https://doi.org/10.1186/s12929-025-01153-7Skeletal muscleMitochondriaDevelopmentMitophagyAutophagyUPS |
| spellingShingle | Fasih A. Rahman Mackenzie Q. Graham Alex Truong Joe Quadrilatero Activation of mitophagy and proteasomal degradation confers resistance to developmental defects in postnatal skeletal muscle Journal of Biomedical Science Skeletal muscle Mitochondria Development Mitophagy Autophagy UPS |
| title | Activation of mitophagy and proteasomal degradation confers resistance to developmental defects in postnatal skeletal muscle |
| title_full | Activation of mitophagy and proteasomal degradation confers resistance to developmental defects in postnatal skeletal muscle |
| title_fullStr | Activation of mitophagy and proteasomal degradation confers resistance to developmental defects in postnatal skeletal muscle |
| title_full_unstemmed | Activation of mitophagy and proteasomal degradation confers resistance to developmental defects in postnatal skeletal muscle |
| title_short | Activation of mitophagy and proteasomal degradation confers resistance to developmental defects in postnatal skeletal muscle |
| title_sort | activation of mitophagy and proteasomal degradation confers resistance to developmental defects in postnatal skeletal muscle |
| topic | Skeletal muscle Mitochondria Development Mitophagy Autophagy UPS |
| url | https://doi.org/10.1186/s12929-025-01153-7 |
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