Loss of autism-candidate CHD8 perturbs neural crest development and intestinal homeostatic balance

Abstract

Individuals with mutations inCHD8present with gastrointestinal complaints, yet the underlying mechanisms are understudied. Here, using a stable constitutivechd8mutant zebrafish model, we found that the loss ofchd8leads to a reduced number of vagal neural crest cells (NCCs), enteric neural and glial progenitors, emigrating from the neural tube, and that their early migration capability was altered. At later stages, although the intestinal colonization by NCCs was complete, we found the decreased numbers of both serotonin-producing enterochromaffin cells and NCC-derived serotonergic neurons, suggesting an intestinal hyposerotonemia in the absence ofchd8. Furthermore, transcriptomic analyses revealed an altered expression of key receptors and enzymes in serotonin and acetylcholine signaling pathways. The tissue examination ofchd8mutants revealed a thinner intestinal epithelium accompanied by an accumulation of neutrophils and the decreased numbers of goblet cells and eosinophils. Last, single-cell sequencing of whole intestines showed a global disruption of the immune balance with a perturbed expression of inflammatory interleukins and changes in immune cell clusters. Our findings propose a causal developmental link betweenchd8, NCC development, intestinal homeostasis, and autism-associated gastrointestinal complaints.