Cigarette smoking inhibits myoblast regeneration by promoting proteasomal degradation of NPAT protein and hindering cell cycle progression

Jianfeng Wang; Jinling Liu; Jingjing Shao; Hongyu Chen; Luyun Cui; Pei Zhang; Yinan Yao; Jianying Zhou; Zhang Bao

doi:10.1016/j.crtox.2024.100161

Cigarette smoking inhibits myoblast regeneration by promoting proteasomal degradation of NPAT protein and hindering cell cycle progression

Curr Res Toxicol. 2024 Mar 2:6:100161. doi: 10.1016/j.crtox.2024.100161. eCollection 2024.

Authors

Jianfeng Wang¹, Jinling Liu², Jingjing Shao¹, Hongyu Chen^{3

4}, Luyun Cui¹, Pei Zhang¹, Yinan Yao¹, Jianying Zhou¹, Zhang Bao¹

Affiliations

¹ Department of Pulmonary and Critical Care Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China.
² Department of Pulmonology, the Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou 310058 China.
³ School of Medicine, Hangzhou City University, Hangzhou 310015, China.
⁴ Institute of Bioinformatics and James D. Watson Institute of Genome Sciences, Zhejiang University, Hangzhou 310058, China.

Abstract

Cigarette smoking (CS) causes skeletal muscle dysfunction, leading to sarcopenia and worse prognosis of patients with diverse systemic diseases. Here, we found that CS exposure prevented C2C12 myoblasts proliferation in a dose-dependent manner. Immunoblotting assays verified that CS exposure promoted the expression of cell cycle suppressor protein p21. Furthermore, CS exposure significantly inhibited replication-dependent (RD) histone transcription and caused S phase arrest in the cell cycle during C2C12 proliferation. Mechanistically, CS deregulated the expression levels of Nuclear Protein Ataxia-Telangiectasia Locus (NPAT/p220). Notably, the proteasome inhibitor MG132 was able to reverse the expression of NPAT in myoblasts, implying that the degradation of CS-mediated NPAT is proteasome-dependent. Overexpression of NPAT also rescued the defective proliferation phenotype induced by CS in C2C12 myoblasts. Taken together, we suggest that CS exposure induces NPAT degradation in C2C12 myoblasts and impairs myogenic proliferation through NPAT associated proteasomal-dependent mechanisms. As an application of the proteasome inhibitor MG132 or overexpression of NPAT could reverse the impaired proliferation of myoblasts induced by CS, the recovery of myoblast proliferation may be potential strategies to treat CS-related skeletal muscle dysfunction.

Keywords: Cell cycle; Cigarette smoking; Myoblast proliferation; NPAT; Proteasome.