LncRNA MEG3 regulates the development of porcine skeletal muscle satellite cells by enhancing HMGA1 stability

Porcine skeletal muscle satellite cells (PSCs) are the core stem cell population for the development of porcine skeletal muscle. In postnatal piglets, PSCs can differentiate into myoblasts and fuse with existing muscle fibers, increasing muscle fiber volume. While the long noncoding RNA MEG3 (MEG3) has been shown to modulate PSC development, its mechanisms remain nebulous. Here, we aim to explore the mechanism whereby MEG3 modulates PSC development. Core interaction regions between MEG3 and CDC23 were detected using truncated constructs combined with RNA pull-down and RNA immunoprecipitation (RIP). Potential CDC23 target proteins were analyzed using coimmunoprecipitation (Co-IP) and bimolecular fluorescence complementation (BiFC). The potential mechanism of MEG3 modulation was then further explored by employing MG-132 and cycloheximide (CHX) treatment and ubiquitination assays. Finally, downstream signaling pathways associated with MEG3 were detected by transcriptome sequencing (RNA-seq) and western blot analysis. The 787–839 nt region of MEG3 and the 464–594aa region of CDC23 are necessary for binding, with MEG3 (Δ787–839 nt) showing a reduced inhibitory effect on proliferation and promoting effect on differentiation. Furthermore, CDC23 promotes HMGA1 ubiquitination via a K48 linkage at the K7 site, significantly shortening its half-life. MEG3 competitively binds CDC23, enhancing HMGA1 stability and protecting it from proteasome degradation. Functional detection and transcriptome sequencing further clarified that MEG3 acts through HMGA1-mediate inhibition of proliferation and promotion of differentiation. Furthermore, MEG3 knockdown, and subsequent HMGA1 downregulation, mediates the activation of ERK signaling, thereby promoting PSC proliferation and inhibiting differentiation. This study demonstrates a novel mechanism of MEG3 regulation in PSC development, implicates potential genetic targets, and provides a theoretical basis for accelerated porcine skeletal muscle development.