Inhibition of IL-6/JAK/STAT3 pathway rescues denervation-induced skeletal muscle atrophy

Ziwei Huang; Lou Zhong; Jianwei Zhu; Hua Xu; Wenjing Ma; Lilei Zhang; Yuntian Shen; Betty Yuen-Kwan Law; Fei Ding; Xiaosong Gu; Hualin Sun

doi:10.21037/atm-20-7269

Inhibition of IL-6/JAK/STAT3 pathway rescues denervation-induced skeletal muscle atrophy

Ann Transl Med. 2020 Dec;8(24):1681. doi: 10.21037/atm-20-7269.

Authors

Affiliations

¹ Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China.
² Department of Thoracic Surgery, Affiliated Hospital of Nantong University, Nantong, China.
³ Department of Orthopedics, Affiliated Hospital of Nantong University, Nantong, China.
⁴ State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Macau, China.

Abstract

Background: The molecular mechanisms underlying denervated skeletal muscle atrophy with concomitant muscle mass loss have not been fully elucidated. Therefore, this study aimed to attain a deeper understanding of the molecular mechanisms underlying denervated skeletal muscle atrophy as a critical step to developing targeted therapy and retarding the concomitant loss of skeletal muscle mass.

Methods: We employed microarray analysis to reveal the potential molecular mechanisms underlying denervated skeletal muscle atrophy. We used in vitro and in vivo atrophy models to explore the roles of the interleukin 6 (IL-6), Janus kinase (JAK), and signal transducers and activators of transcription 3 (STAT3) in muscle atrophy.

Results: In this study, microarray analysis of the differentially expressed genes demonstrated that inflammation-related cytokines were markedly triggered and IL-6/JAK/STAT3 signaling pathway was strongly activated during denervated skeletal muscle atrophy. The high level of IL-6 enhanced C2C12 myotube atrophy through the activation of JAK/STAT3, while inhibiting JAK/STAT3 pathway by ruxolitinib (a JAK1/2 inhibitor) or C188-9 (a STAT3 inhibitor) significantly attenuated C2C12 myotube atrophy induced by IL-6. Pharmacological blocking of IL-6 by tocilizumab (antibody against IL-6 receptor) and pharmacological/genetic inhibition of JAK/STAT3 pathway by ruxolitinib/C188-9 (JAK/STAT3 inhibitor) and STAT3 short hairpin RNA (shRNA) lentivirus in tibialis anterior muscles could suppress muscle atrophy and inhibit mitophagy, and was accompanied by the decreased expression of atrophic genes (MuRF1 and MAFbx) and autophagy-related genes (PINK1, BNIP3, Beclin 1, ATG7, and LC3B).

Conclusions: Taken together, the results suggest that IL-6/JAK/STAT3 pathway may be a principal mediator in denervated skeletal muscle atrophy, meaning targeted therapy against IL-6/JAK/STAT3 pathway might have potential as a therapeutic strategy for prevention of skeletal muscle atrophy.

Keywords: Denervation; IL-6/JAK/STAT3; inflammation; skeletal muscle atrophy.