Muscles that are injured or atrophied by aging undergo myogenic regeneration. Although myoblasts play a pivotal role in myogenic regeneration, their function is impaired with aging. MicroRNAs (miRNAs) are also involved in myogenic regeneration. MiRNA (miR)-1 and miR-133a are muscle-specific miRNAs that control the proliferation and differentiation of myoblasts. In this study, we determined whether miR-1 and miR-133a expression in myoblasts is altered with cellular senescence and involved in senescence-impaired myogenic differentiation. C2C12 murine skeletal myoblasts were converted to a replicative senescent state by culturing to a high passage number. Although miR-1 and miR-133a expression was largely induced during myogenic differentiation, expression was suppressed in cells at high passage numbers (passage 10 and/or passage 20). Although the senescent myoblasts exhibited a deterioration of myogenic differentiation, transfection of miR-1 or miR-133a into myoblasts ameliorated cell fusion. Treatment with the glutaminase 1 inhibitor, BPTES, removed senescent cells from C2C12 myoblasts with a high passage number, whereas myotube formation and miR-133a expression was increased. In addition, primary cultured myoblasts prepared from aged C57BL/6J male mice (20 months old) exhibited a decrease in miR-1 and miR-133a levels compared with younger mice (3 months old). The results suggest that replicative senescence suppresses muscle-specific miRNA expression in myoblasts, which contributes to the senescence-related dysfunction of myogenic regeneration.
Copyright: © 2023 Shintani-Ishida et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.