MiR-21 regulates skeletal muscle atrophy and fibrosis by targeting TGF-beta/SMAD7-SMAD2/3 signaling pathway
Xianmin Song,
Fei Liu,
Mengjie Chen,
Minhui Zhu,
Hongliang Zheng,
Wei Wang,
Donghui Chen,
Meng Li,
Shicai Chen
Affiliations
Xianmin Song
From the Department of Otorhinolaryngology & Head and Neck Surgery, Changhai Hospital, Naval Military Medical University (The Second Military Medical University), Shanghai, 200433, China
Fei Liu
From the Department of Otorhinolaryngology & Head and Neck Surgery, Changhai Hospital, Naval Military Medical University (The Second Military Medical University), Shanghai, 200433, China
Mengjie Chen
From the Department of Otorhinolaryngology & Head and Neck Surgery, Changhai Hospital, Naval Military Medical University (The Second Military Medical University), Shanghai, 200433, China
Minhui Zhu
From the Department of Otorhinolaryngology & Head and Neck Surgery, Changhai Hospital, Naval Military Medical University (The Second Military Medical University), Shanghai, 200433, China
Hongliang Zheng
From the Department of Otorhinolaryngology & Head and Neck Surgery, Changhai Hospital, Naval Military Medical University (The Second Military Medical University), Shanghai, 200433, China
Wei Wang
From the Department of Otorhinolaryngology & Head and Neck Surgery, Changhai Hospital, Naval Military Medical University (The Second Military Medical University), Shanghai, 200433, China
Donghui Chen
Department of Otorhinolaryngology, The First Affiliate Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing, 210029, Jiangsu, China; Corresponding author.
Meng Li
From the Department of Otorhinolaryngology & Head and Neck Surgery, Changhai Hospital, Naval Military Medical University (The Second Military Medical University), Shanghai, 200433, China; Corresponding author.
Shicai Chen
From the Department of Otorhinolaryngology & Head and Neck Surgery, Changhai Hospital, Naval Military Medical University (The Second Military Medical University), Shanghai, 200433, China; Corresponding author.
Long-term denervation-induced atrophy and fibrosis of skeletal muscle due to denervation leads to poor recovery of muscle function. Studies have shown that the transforming growth factor-β1 (TGF-β1)-Smad signaling pathway plays a central role in muscle atrophy and fibrosis. Recent studies demonstrate the role of microRNAs (miRs) in various pathological conditions, including muscle regeneration. miR-21 has been shown to play a dynamic role in inflammatory responses and in accelerating injury responses to fibrosis. We used both RNA sequencing and quantitative RT-PCR strategies to examine the alternations of miRNAs during denervation-induced gastrocnemius muscle atrophy and fibrosis. Our data showed that MiR-21 was upregulated in denervated gastrocnemius muscle tissue, and TGF-β1treatment increased miR-21 expression. Inhibition of miR-21 reduced gastrocnemius muscle fibrosis and significantly downregulated the expression of p-SMAD2/3 and the fibrosis-associated markers TGF-β1, connective tissue growth factor, alpha smooth muscle actin. Masson's trichrome staining revealed that atrophy and fibrosis in gastrocnemius muscle tissue were reduced in the miR-21 inhibition group compared to the control group. We confirmed that SMAD7 is a direct target of miR-21 using a dual luciferase assay. Furthermore, Immunofluorescence and Western blot analyses revealed that miR-21 inhibition reduced SMAD2/3 phosphorylation and nuclear translocation. While SMAD7-siRNA abolished the effect. Consequently, the discovery that miR-21 regulates the atrophy and fibrosis of the gastrocnemius muscle offers a possible therapeutic approach for their management.
