O1125: Transcriptional Profiling and Functional Analysis of Intestinal Mucosa Obtained from Hirschsprung's Disease Patients Undergoing Colon Resection

Background: Hirschsprung’s disease (HD) is a congenital birth defect of enteric nervous system affecting distal colon. Even after surgical resection, the majority of HD patients develop lifelong gastrointestinal problems including the development of Hirschsprung associated enterocolitis. A better understanding of HD is needed to improve patient outcome. We aimed to compare the transcriptional profile and function of diseased (aganglionic) tissue from HD patients with matched normal tissue (ganglionic) from unaffected region.

Methods: RNAseq was performed on mucosal tissues obtained from aganglionic and ganglionic regions of HD patients (n=6) and controls (n=3). Functional differences between matched aganglionic and ganglionic regions from HD patients were investigated by characterizing colonic organoids generated from these tissues.

Results: When compared to control mucosal tissues, HD mucosal tissues revealed a strong proinflammatory response, with increased expression of genes encoding CXCL5, IL1B, IL17F, ICAM1, TNIP3, C2CD4B, OSM, CD44, GPR4, HIF1A, SERPINE1 and SOCS3. Genes involved in cell differentiation and proliferation including WNT2, HOXC8, FOSL1 were also differentially upregulated in HD patients compared to controls. This response occurred concomitant with decreased expression of genes encoding mucins (MUC17, MUC2, MUC5AC) in HD patients compared to controls. In contrast, very few transcriptional changes were observed between aganglionic and ganglionic mucosal regions of the HD patients. Furthermore, the colonic organoids derived from the aganglionic and ganglionic regions of HD patients did not differ in epithelial cell differentiation, epithelial barrier formation and in response to stimulation with bacterial metabolites and pro-inflammatory cytokines.

Conclusion: The results of this study indicate that despite the histologic and phenotypic differences between the aganglionic and ganglionic regions of HD patients, the epithelium from the two regions have similar changes at the molecular and functional level compared to control tissue. These results suggest that there is a perturbed underlying gene expression in HD patients’ colonic epithelium and that that perturbation is persevered in the ganglionic or “unaffected” area of colon of these patients.