Analysis of Enteric Neural Crest Cell Migration Using Heterotopic Grafts of Embryonic Guts

Hirschsprung disease (HSCR), also named aganglionic megacolon, is a severe congenital malformation characterized by a lack of enteric nervous system (ENS) in the terminal regions of the bowel (Bergeron et al., 2013). As the ENS notably regulates motility in the whole gastrointestinal track, the segment without neurons remains tonically contracted, resulting in functional intestinal obstruction and accumulation of fecal material (megacolon). HSCR occurs when enteric neural progenitors of vagal neural crest origin fail to fully colonize the developing intestines. These "enteric" neural crest cells (ENCCs) have to migrate in a rostro-caudal direction during a fixed temporal window, which is between embryonic day (e) 9.5 and e14.5 in the mouse (Obermayr et al., 2013). Recently, our group generated a new HSCR mouse model called Holstein in which migration of ENCCs is impaired because of increased collagen VI levels in their microenvironment (Soret e al., 2015). Here, we describe the method that allowed us to demonstrate the cell-autonomous nature of this migration defect. In this system adapted from a previously described heterotopic grafting approach (Breau et al., 2006), the donor tissue is a fully colonized segment of e12.5 midgut while the host tissue is an aneural segment of e12.5 hindgut. Extent of ENCC migration in host tissue is assessed after 24 h of culture and is greatly facilitated when donor tissue has a transgenic background such as the Gata4-RFP (Pilon et al., 2008) that allows endogenous labeling of ENCCs with fluorescence. Depending of the genetic background of donor and host tissues, this approach can allow evaluating both cell-autonomous and non-cell-autonomous defects of ENCC migration.