Open Accessm 6 A demethylase ALKBH5 drives denervation‐induced muscle atrophy by targeting HDAC4 to activate FoxO3 signalling
Author(s) -
Liu Yuantong,
Zhou Tianjian,
Wang Qinghe,
Fu Runhan,
Zhang Zengfu,
Chen Nandi,
Li Zhizhong,
Gao Guoyong,
Peng Songlin,
Yang Dazhi
Publication year - 2022
Publication title -
journal of cachexia, sarcopenia and muscle
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.803
H-Index - 66
eISSN - 2190-6009
pISSN - 2190-5991
DOI - 10.1002/jcsm.12929
Subject(s) - foxo3 , denervation , demethylase , biology , muscle atrophy , western blot , atrophy , skeletal muscle , microbiology and biotechnology , endocrinology , medicine , epigenetics , protein kinase b , signal transduction , biochemistry , gene , genetics
Background Skeletal muscle atrophy is a common clinical manifestation of various neurotrauma and neurological diseases. In addition to the treatment of primary neuropathies, it is a clinical condition that should be investigated. FoxO3 activation is an indispensable mechanism in denervation‐induced muscle atrophy; however, upstream factors that control FoxO3 expression and activity have not been fully elucidated. N 6 ‐methyladenosine (m 6 A) methylation is a novel mode of epitranscriptional gene regulation that affects several cellular processes. However, the biological significance of m 6 A modification in FoxO3‐dependent atrophy is unknown. Methods We performed gain‐of‐function and loss‐of‐function experiments and used denervation‐induced muscle atrophy mouse model to evaluate the effects of m 6 A modification on muscle mass control and FoxO3 activation. m 6 A‐sequencing and mass spectrometry analyses were used to establish whether histone deacetylase 4 (HDAC4) is a mediator of m 6 A demethylase ALKBH5 regulation of FoxO3. A series of cellular and molecular biological experiments (western blot, immunoprecipitation, half‐life assay, m 6 A‐MeRIP‐qPCR, and luciferase reporter assays among others) were performed to investigate regulatory relationships among ALKBH5, HDAC4, and FoxO3. Results In skeletal muscles, denervation was associated with a 20.7–31.9% decrease in m 6 A levels ( P < 0.01) and a 35.6–115.2% increase in demethylase ALKBH5 protein levels ( P < 0.05). Overexpressed ALKBH5 reduced m 6 A levels, activated FoxO3 signalling, and induced excess loss in muscle wet weight (−10.3% for innervation and −11.4% for denervation, P < 0.05) as well as a decrease in myofibre cross‐sectional areas (−35.8% for innervation and −33.3% for denervation, P < 0.05) during innervation and denervation. Specific deletion of Alkbh5 in the skeletal muscles prevented FoxO3 activation and protected mice from denervation‐induced muscle atrophy, as evidenced by increased muscle mass (+16.0%, P < 0.05), size (+50.0%, P < 0.05) and MyHC expression (+32.6%, P < 0.05). Mechanistically, HDAC4 was established to be a crucial central mediator for ALKBH5 in enhancing FoxO3 signalling in denervated muscles. ALKBH5 demethylates and stabilizes Hdac4 mRNA. HDAC4 interacts with and deacetylates FoxO3, resulting in a significant increase in FoxO3 expression (+61.3–82.5%, P < 0.01) and activity (+51.6–122.0%, P < 0.001). Conclusions Our findings elucidate on the roles and mechanisms of ALKBH5‐mediated m 6 A demethylation in the control of muscle mass during denervation and activation of FoxO3 signalling by targeting HDAC4. These results suggest that ALKBH5 is a potential therapeutic target for neurogenic muscle atrophy.