Intestinal fibrosis in aganglionic segment of Hirschsprung's disease revealed by single‐cell RNA sequencing

BACKGROUND: Hirschsprung's disease (HSCR) is a relatively common congenital disability. Accumulating extracellular matrix (ECM) prompts intestinal fibrosis remodelling in the aganglionic segments of HSCR. The contributions of various cellular subsets in the fibrogenesis of HSCR segments are poorly understood. METHODS: Single‐cell transcriptomics from 8 aganglionic segments and 5 normal segments of 7 HSCR subjects and 26 healthy segments of seven healthy donors were analysed. Fibrotic phenotype and alterations were explored using differential expression analysis and single‐cell trajectory analysis. Fibrosis‐related transcription factors were inferred through single‐cell regulatory network inference. Bulk transcriptomic data, proteomic data, immunohistochemistry (IHC) and real‐time polymerase chain reaction were used to validate the alterations in the HSCR intestine. RESULTS: Various collagen, fibronectin and laminin protein‐coding genes expression were up‐regulated in the stromal and glial cells of the HSCR intestine. The number of fibroblasts and myofibroblasts in the aganglionic segments increased, and more myofibroblasts were activated at an earlier stage in HSCR segments, which infers that there is an intestinal fibrosis phenotype in HSCR segments. The fibrotic regulators POSTN, ANXA1 and HSP70 were highly expressed in the ECM‐related cellular subsets in the transitional segments and aganglionic segments. The transcription factor regulatory network revealed that fibrosis‐related and megacolon‐related NR2F1 in the fibroblasts and glial subsets was up‐regulated in the aganglionic segment. CONCLUSIONS: This work identifies intestinal fibrosis and related regulators in aganglionic segments of HSCR; hence, anti‐fibrotic therapy may be considered to prevent HSCR‐associated enterocolitis (HAEC), relieve intestinal stricture and improve cell therapy.