Retinoic acid (RA) signaling is essential for enteric nervous system (ENS) development since vitamin A deficiency or mutations in RA signaling profoundly reduce bowel colonization by ENS precursors. These RA effects could occur because of RA activity within the ENS lineage or via RA activity in other cell types. To define cell-autonomous roles for retinoid signaling within the ENS lineage at distinct developmental time points, we activated a potent floxed dominant-negative RA receptor α (RarαDN) in the ENS using diverse CRE recombinase-expressing mouse lines. This strategy enabled us to block RA signaling at pre-migratory, migratory, and post-migratory stages for ENS precursors. We found that cell-autonomous loss of retinoic acid receptor (RAR) signaling dramatically affects ENS development. CRE activation of RarαDN expression at pre-migratory or migratory stages caused severe intestinal aganglionosis, but at later stages, RarαDN induced a broad range of phenotypes including hypoganglionosis, submucosal plexus loss, and abnormal neural differentiation. RNA-sequencing highlighted distinct RA-regulated gene sets at different developmental stages. These studies show complicated context-dependent RA-mediated regulation of ENS development.
Tao Gao, Elizabeth C. Wright-Jin, Rajarshi Sengupta, Jessica B. Anderson, Robert O. Heuckeroth