<em>Ex Vivo</em> Culture of Pharyngeal Arches to Study Heart and Muscle Progenitors and Their Niche

Abstract

The pharyngeal mesoderm of developing embryos contributes to broad regions of head and heart musculature. We have developed a novel method to study head and heart progenitor cell development with pharyngeal arches (also known as branchial arches) ex vivo. Using this method, we have recently described that the second pharyngeal arch contains self-renewing heart progenitors and serves as a microenvironment for expansion of the progenitors during mouse heart development. The progenitor cells remain undifferentiated and expansive inside the arch, but quickly become functional cardiomyocytes as they migrate out of the arch. We also reported that first pharyngeal arch contains muscle progenitors giving rise to myotubes after leaving the arch. Here, we demonstrate the procedure for the dissection and ex-vivo culture of first and second pharyngeal arches from developing mouse embryos. The method enables one to study head and heart progenitor/muscle development, including cardiomyocyte and myotube formation in detail ex vivo.

Chicken Second Branchial Arch Progenitor Cells Contribute to Heart Musculature in vitro and in vivo

“…In Numb and Numb-like knock-out mice, the right ventricle and OT (derived from the second cardiac field) failed to develop normally and the BA2 was also smaller [Shenje et al, 2014]. Thus, the CPCs within the BA2 are self-renewing cells and this arch serves as a niche for cardiac progenitors of the murine developing heart [Bruneau, 2014;Shenje et al, 2014;Andersen and Kwon, 2015].…”

β1-integrin is a cell-autonomous factor mediating the Numb pathway for cardiac progenitor maintenance

“…Prior to myocardialization, Mesp1 + cell-derived SHF cells express CPC markers such as Isl1, Tbx1, Sall1(Cai et al, 2003; Huynh et al, 2007; Morita et al, 2016). Recently, a subset of SHF cells, expressing Isl1 but not Nkx2.5, were identified in the second pharyngeal arch (PA2), where they undergo homogeneous renewal and expansion in the presence of PA2 cells (Andersen and Kwon, 2015; Shenje et al, 2014). Intriguingly, the process required the endocytic adopter proteins Numb and Numbl, known to mediate asymmetric cell divisions and self-renewal in other contexts (Petersen et al, 2002; Roegiers and Jan, 2004).…”