Cell-autonomous retinoic acid receptor signaling has stage-specific effects on mouse enteric nervous system.

Tao Gao,Elizabeth C. Wright-Jin,Robert O. Heuckeroth,Jessica B. Anderson,Rajarshi Sengupta

doi:10.1172/jci.insight.145854

Tao Gao, Elizabeth C. Wright-Jin + Show 3 more

Open Access

https://doi.org/10.1172/jci.insight.145854

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Abstract

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 premigratory, migratory, and postmigratory stages for ENS precursors. We found that cell-autonomous loss of RA receptor (RAR) signaling dramatically affected ENS development. CRE activation of RarαDN expression at premigratory 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.

Highlights

The enteric nervous system (ENS) is a complex network of neurons and glia that resides in the bowel wall and is essential for intestinal function [1, 2]
RarαDNLoxP/+; Wnt1Cre+ mice are viable at E12.5, but they die by E14.5 (Table 1)
To determine if RarαDN expression within neural crest–derived ENS precursors acts at earlier developmental stages, we examined E10.5 whole embryo via 3DISCO tissue clearing [38] and confocal microscopy (Figure 3, A and B)

Summary

Introduction

The enteric nervous system (ENS) is a complex network of neurons and glia that resides in the bowel wall and is essential for intestinal function [1, 2]. The extent of bowel aganglionosis dramatically increased when Ret heterozygosity was combined with vitamin A deficiency, suggesting potent gene-environment interactions in mice [26]. Consistent with these observations, loss of the primary RA synthesis enzyme retinaldehyde dehydrogenase 2 (Raldh2) causes severe intestinal aganglionosis in mice [29], with more minor effects of murine Raldh and Raldh mutations [25]. Maternal vitamin A deficiency or excess can cause intestinal hypoganglionosis without aganglionosis in rats and mice [22, 28, 32] While these results clearly show that RA signaling is needed for ENS development, many questions remain.

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