Notch Signaling Slows Down the Progression of Embryonic Myogenic Differentiation in Landrace

BackgroundDelving into porcine embryonic myogenesis is the key to elucidating the complex regulation of breed-specific differences in growth performance and meat production. Increasing evidence proved that pigs with less meat production showed more intense embryonic myogenesis, but little is known about the underlying mechanisms. ResultsIn this study, we confirmed that the differentiation process of myogenic progenitors in Lantang pig (LT, fat) was faster than that in Landrace pig (LR, lean), which resulted in more differentiated myoblasts (Pax7-/MyoD+) but less myogenic progenitors (Pax7+/MyoD-) in LT at 35 days post-conception (35dpc). Additionally, in vitro, embryonic myogenic progenitors isolated from LT showed stronger differentiation capacity with earlier expression of MyoD. Furthermore, the expression levels of genes related to Notch signaling in LR progenitor cells were significantly higher than that of LT, while there was no significant difference between the two breeds in gene expression levels of Wnt and Akt/mTOR pathway. Inhibition of Notch signaling or knockdown of Pax7 promotes myogenic differentiation of primary progenitor cells or myoblasts, while activation of Notch signaling or overexpression of Pax7 has the opposite effects.ConclusionsMyogenic differentiation is more rapid in LT than that in LR at 35dpc. Mechanically, Notch signaling facilitates maintenance of myogenic progenitor cells and antagonizes myogenic differentiation by promoting Pax7 expression but preventing MyoD expression in LR.