ApoE and Fibroblast–Macrophage Interaction in the Aganglionic Segment of Hirschsprung’s Disease-Associated Enterocolitis

Background: The pathogenesis of Hirschsprung’s disease-associated enterocolitis (HAEC) remains unclear. Currently, no definitive studies have elucidated the communication between intestinal macrophages and fibroblasts during the development of HAEC, nor their specific functional roles in this process. Methods: The first step is utilizing single-cell transcriptomics and spatial transcriptomic sequencing techniques to validate the phenotypes and corresponding spatial location characteristics of intestinal fibroblasts in the patient with HAEC. The second is verifying the mechanism whereby specific subtypes of fibroblasts and macrophages communicate via apolipoprotein E (ApoE) and modulate corresponding inflammatory pathways using co-culture, Western blot and other molecular biology techniques. Results: As HAEC progressed, JUN expression was significantly upregulated in CTHRC1+PRRX1+ fibroblasts enriched in the submucosal layer in the aganglionic segment. In vitro experiments showed JUN-overexpressing 3T3-L1 cells exhibited increased ApoE secretion. ApoE may interact with macrophages and potentially suppress their inflammation through the p38/MAPK and NF-κB pathways. Conclusions:CTHRC1+PRRX1+ fibroblasts and ApoE may represent a potential mechanistic target for future investigation into inhibiting the progression of the aganglionic segment in HAEC and treating colitis.