Human enteric glia diversity in health and disease: new avenues for the treatment of Hirschsprung disease.

Background And Aims: The enteric nervous system (ENS), comprised of neurons and glia, regulates intestinal motility. Hirschsprung disease (HSCR) results from defects in ENS formation, yet while neuronal aspects have been extensively studied, enteric glia remain disregarded. This study aimed to explore enteric glia diversity in health and disease.

Methods: Full-thickness intestinal resection material from pediatric controls and HSCR patients was collected, dissociated and enriched for the ENS population through fluorescence-activated cell sorting. Single-cell RNA sequencing was performed to uncover the transcriptomic diversity of the ENS in HSCR patients and controls, as well as in wildtype and ret mutant zebrafish. Immunofluorescence and fluorescence in situ hybridization confirmed the presence of distinct subtypes.

Results: Two major enteric glial classes emerged in the pediatric intestine: Schwann-like enteric glia, reminiscent of Schwann cells, and Enteric glia, expressing classical glial markers. Comparative analysis with previously published datasets confirmed our classification and revealed that whilst classical enteric glia are predominant prenatally, Schwann-like enteric glia become more abundant postnatally. In HSCR, ganglionic segments mirrored controls, while aganglionic segments, only featured Schwann-like enteric glia. Leveraging the regenerative potential of Schwann cells, we explored therapeutic options using a ret mutant zebrafish. Prucalopride, a serotonin-receptor (5-HT) agonist, induced neurogenesis partially rescuing the HSCR phenotype in ret mutants.

Conclusion: Two major enteric glial classes were identified in the pediatric intestine, highlighting the significant postnatal contribution of Schwann-like enteric glia to glial heterogeneity. Crucially, these glial subtypes persist in aganglionic segments of HSCR patients, offering a new target for their treatment using 5-HT agonists.