New Insight into the Role of the Leucine Aminopeptidase 3 (LAP3) in Cell Proliferation and Myogenic Differentiation in Sheep Embryonic Myoblasts

Abstract

Previous genome-wide association studies (GWAS) have found that LAP3 may have the potential function to impact sheep muscle development. In order to further explore whether LAP3 expression has an important role in the development of sheep embryonic myoblasts, we conducted the spatiotemporal expression profile analysis of LAP3 at the tissue and cellular level. Then we used small interfering RNA and eukaryotic recombinant vectors to perform gain/loss-of-function analysis of LAP3. CCK-8 detection, EdU staining, and flow cytometry were used to investigate the impact of LAP3 knockdown or overexpression on the proliferation of embryonic myoblasts. In addition, cell phenotype observation, MyHC indirect immunofluorescence, and quantitative detection of the expression changes of myogenic regulatory factors (MRFs) were used to explore the effect of LAP3 on myogenic differentiation. The results showed that the LAP3 expression level in muscle tissue of fetuses was significantly higher than that in newborn lambs and adult sheep, and its expression level on day 3 of differentiation was also significantly higher than that in the proliferation phase and other differentiation time points. LAP3 silencing could significantly increase cell viability and EdU-positive cells, as well as prolonging the length of S phase of myoblasts to promote proliferation, while the results were reversed when LAP3 was overexpressed. Moreover, LAP3 silencing significantly hindered myotube formation and down-regulated the expression levels of MRFs from day 5 to day 7 of terminal differentiation, while the results were reversed when LAP3 was highly expressed. Overall, our results suggested that the expression of LAP3 impacts on the development of sheep embryonic myoblasts which provides an important theoretical basis for molecular breeding of meat production in sheep.

The aminopeptidase LAP3 suppression accelerates myogenic differentiation via the AKT‐TFE3 pathway in C2C12 myoblasts

“…These findings suggest that LAP3 is regulating myogenin expression through the changes in its subcellular localization and the reduction of its activity during myogenic differentiation. Conversely, a recent study in sheep embryonic myoblasts found that suppression of LAP3 expression inhibited myogenic differentiation (Ge et al, 2022), indicating that the regulatory mechanism of LAP3 may vary across species. It is generally accepted that the differentiation ability of C2C12 myoblasts has distinct characteristics from primary myoblasts and satellite cells (Grabowska et al, 2011).…”

Mitochondrial-related hub genes in dermatomyositis: muscle and skin datasets-based identification and in vivo validation

“…LAP3 plays a key role in cleaving amino acids from the N-terminus of peptides and proteins, essential for regulating protein degradation and peptide metabolism ( Li et al, 2022 ). Notably, LAP3 has been found to influence muscle development, with its silencing significantly impeding muscle fiber formation and heightened LAP3 expression markedly promoting muscle fiber formation in a sheep model ( Ge et al, 2022 ). Furthermore, LAP3 contributes to the depletion of arginine induced by IFN-γ in a bovine mammary epithelial cell model ( Li et al, 2022 ).…”

Identification of candidate genes for feed efficiency and growth traits in Wenchang chickens

“…LAP3 gene variation may be the cause of some species growth rates and some variation associated with significant genetic polymorphism of the traits of interest in breeding, with potential applications in animal breeding, and its SNP and its association with [43][44][45][46][47]. In poultry studies, the LAP3 gene was found to be associated with chicken growth traits [17].…”