MYSM1 regulates the proliferation and differentiation of bovine skeletal muscle satellite cells via BRG1-mediated activation of the AKT/mTOR/NF-κB signaling pathway

Zhang, Chujie; Li, yue; Zhang, wenwen; Ma, Tengxia; Li, Xin; Guo, Yiwen; Zhang, Linlin; Ding, Xiangbin; Hu, Debao

doi:.0.0.0

Article

https://doi.org/10.5713/ab.250773 [Accepted] Published online December 18, 2025.

MYSM1 regulates the proliferation and differentiation of bovine skeletal muscle satellite cells via BRG1-mediated activation of the AKT/mTOR/NF-κB signaling pathway

Chujie Zhang¹

, Debao Hu^1,*

Department of Agriculture University, Tianjin, China, Tianjin, China

Correspondence: Debao Hu,Email: hudebao@tjau.edu.cn

Received: 14 October 2025 • Revised: 19 November 2025 • Accepted: 13 December 2025

Abstract

Objective
This study sought to delineate the molecular mechanisms through which the deubiquitinase MYSM1 modulates the proliferation and differentiation of bovine skeletal muscle satellite cells (BSMSCs), thereby offering novel theoretical insights into the regulation of muscle growth and development in beef cattle.
Methods
An in vitro BSMSC model was established to investigate the role of MYSM1. Temporal expression patterns of MYSM1 during cell proliferation and differentiation were analyzed using qRT-PCR. MYSM1 knockdown models were generated, and expression of proliferation markers (PAX7, Ki67) and differentiation markers (MYHC, MYOG) was examined by qRT-PCR and Western blotting. Protein–protein interaction predictions (STRING database) identified BRG1 as a potential MYSM1 interactor, and its function was assessed. Downstream signaling pathways were analyzed by detecting phosphorylation changes in AKT/mTOR pathway proteins. In addition, global histone ubiquitination (H2AK119ub1) and methylation (H3K27me3, H3K4me3) were measured following MYSM1 knockdown.
Results
MYSM1 expression was dynamically regulated, exhibiting significant upregulation during differentiation and reaching a peak at days 2–3 (p < 0.05). Silencing of MYSM1 markedly decreased the expression of PAX7, Ki67, MYHC, and MYOG (p < 0.05). Histone modification analyses demonstrated elevated levels of H2AK119ub1 and H3K27me3, accompanied by reduced H3K4me3 (p < 0.05). Mechanistic investigations further revealed that MYSM1 knockdown suppressed BRG1 expression (p < 0.05), and silencing of BRG1 produced comparable reductions in proliferation- and differentiation-related markers. Moreover, interference with either MYSM1 or BRG1 significantly attenuated activation of the AKT/mTOR/NF-κB pathway, as evidenced by decreased phosphorylation of AKT1, mTOR, and p65 (p < 0.05).
Conclusions
MYSM1 promotes the proliferation and differentiation of BSMSCs through BRG1-mediated epigenetic regulation and activation of the AKT/mTOR/NF-κB signaling cascade. These findings establish a dual-target framework that not only advances the understanding of muscle development in beef cattle but also offers potential strategies for regenerative therapies.

Keywords: MYSM1; BRG1; Satellite cells of bovine skeletal muscle; Epigenetic modifications of histones; AKT/mTOR/NF -κB signaling pathway