MG53 Deficiency Mediated Skeletal Muscle Dysfunction in Chronic Obstructive Pulmonary Disease via Impairing Mitochondrial Fission

Myokine dysregulation and mitochondrial dysfunction are implicated in the pathogenesis of sarcopenia in chronic obstructive pulmonary disease. The objective of this study is to explore the role of myokines and mitochondrial dysfunction in sarcopenia in chronic obstructive pulmonary disease. We identified mitsugumin 53 and its clinical correlation through an enzyme-linked immunosorbent assay using the plasma samples of patients with chronic obstructive pulmonary disease. The role of mitsugumin 53 was confirmed in mitsugumin 53-knockout mice. The underlying mechanisms were investigated using multi-omics sequencing, live-cell imaging, and histological and molecular experiments. The effectiveness and safety of recombinant mitsugumin 53 in treating cigarette smoke-induced muscle dysfunction were evaluated in vitro and in vivo. Plasma mitsugumin 53 levels were decreased in patients with chronic obstructive pulmonary disease and were associated with skeletal muscle dysfunction. Mitsugumin 53 deficiency exacerbated cigarette smoking-induced skeletal muscle atrophy. In muscle cells, mitsugumin 53 co-localized with the mitochondria and regulated mitochondrial fission. As a lipid transporter, mitsugumin 53 directly bound to the mitochondria-specific lipid cardiolipin and participated in maintaining mitochondrial homeostasis and membrane integrity. As an E3-ligase, mitsugumin 53 deletion triggered BCL2L13-mediated mitochondrial fission upon cigarette smoking stimulation. Supplementation with recombinant mitsugumin 53 significantly alleviated cigarette smoking-induced muscle atrophy and rescued mitochondrial dysfunction in vitro and in vivo. Mitsugumin 53 is a vital regulator of sarcopenia in patients with chronic obstructive pulmonary disease. Thus, mitsugumin 53 and mitochondrial fission may be promising therapeutic targets for muscle dysfunction in chronic obstructive pulmonary disease.