Altered goblet cell function in Hirschsprung's disease.

Abstract

Hirschsprung's disease-associated enterocolitis (HAEC) is the most serious complication of Hirschsprung's disease (HSCR). HAEC occurs in 17-50% of patients with HSCR and may occur before or after a properly performed pull-through operation. The pathogenesis of HAEC is poorly understood. It is well recognized that a complex mucosal barrier protects, as the first line of defense, the surface of healthy intestinal tract from adhesion and invasion by luminal micro-organisms. Within the intestinal epithelium, goblet cells secrete gel-forming mucins, the major component of mucus, which block the direct attachment of commensal bacteria to the epithelial layer. Mucin 2 (MUC2) is the predominant mucin expressed in humans. Trefoil factor 3 (TFF3) synergizes with mucin and enhances the protective barrier properties of the mucus layer. SAM pointed domain-containing ETS transcription factor (SPDEF) drives terminal differentiation and maturation of secretory progenitors into goblet cells. Krueppel-like factor 4 (KLF4) is a goblet cell-specific differentiation factor in the colon and controls goblet cell differentiation and activates mucin synthesis. We hypothesized that the goblet cell function in the ganglionic pulled-through bowel in HSCR is abnormal and, therefore, we investigated the changes in goblet cell differentiation and functional expression of mucin in the bowel specimens from patients with HSCR. We investigated MUC2, TFF3, SPDEF and KLF4 expression, and the goblet cell population in the ganglionic and aganglionic bowel of HSCR patients (n = 10) and controls (n = 10) by qPCR, Western blotting, confocal immunofluorescence, and alcian blue staining. The qPCR and Western blotting analysis revealed that TFF3, SPDEF and KLF4 expressions were significantly downregulated in the aganglionic and ganglionic colon of patients with HSCR as compared to controls (p < 0.05). Alcian blue staining revealed that the goblet cell population was significantly decreased in aganglionic and ganglionic colon as compared to controls (p < 0.05). Confocal microscopy revealed a markedly decreased expression of TFF3, SPDEF and KLF4 in colonic epithelium of patients with HSCR as compared to controls. This is, to our knowledge, the first report of decreased expression of TFF3, SPDEF, KLF4, and goblet cell population in the colon of patients with HSCR. Altered goblet cell function may result in intestinal barrier dysfunction contributing to the development of HAEC.