Function and Expression of Cystic Fibrosis Transmembrane Conductance Regulator after Small Intestinal Transplantation in Mice

Abstract

The secretion function of intestinal graft is one of the most important factors for successful intestinal transplantation. Cystic fibrosis transmembrane conductance regulator (CFTR) mediates HCO3 - and Cl- secretions in intestinal epithelial cells. In this study, we made investigation on the expression and function of CFTR in an experimental model of murine small intestinal transplantation. Heterotopic intestinal transplantations were performed in syngeneic mice. The mRNA and protein expressions of CFTR were analyzed by real time PCR and western blot. Murine intestinal mucosal HCO3 - and Cl- secretions were examined in vitro in Ussing chambers by the pH stat and short circuit current (Isc) techniques. The results showed that forskolin, an activator of CFTR, stimulated jejunal mucosal epithelial HCO3 - and Cl- secretions in mice, but forskolin-stimulated HCO3 - and Cl- secretions in donor and recipient jejunal mucosae of mice after heterotopic jejunal transplantation were markedly decreased, compared with controls (P<0.001). The mRNA and protein expression levels of CFTR in donor and recipient jejunal mucosae of mice were also markedly lower than those in controls (P<0.001), and the mRNA and protein expression levels of tumor necrosis factor α (TNFα) were markedly increased in donor jejunal mucosae of mice (P<0.001), compared with controls. Further experiments showed that TNFα down-regulated the expression of CFTR mRNA in murine jejunal mucosa. In conclusion, after intestinal transplantation, the function of CFTR was impaired, and its mRNA and protein expressions were down-regulated, which may be induced by TNFα.

IDO expressing dendritic cells suppress allograft rejection of small bowel transplantation in mice by expansion of Foxp3+ regulatory T cells

“…Mice were anesthetized by inspiration of isoflurane (1.5 ml/min). The surgery procedure was performed as described [25]. In brief, about 1.5 cm of donor's upper portion of jejunum was harvested with Carrel's patches of superior mesenteric artery (SMA) and portal vein (PV).…”

CFTR-mediated anion secretion across intestinal epithelium-like Caco-2 monolayer under PTH stimulation is dependent on intermediate conductance K+ channels

“…As a principal anion transporter in airway epithelial cells, pancreatic ductal cells, and intestinal epithelial cells, cystic fibrosis transmembrane conductance regulator (CFTR) is responsible for Cl Ϫ and HCO 3 Ϫ secretion, and it also plays a critical role in fluid secretion in epithelial cells (27,30,45,49,53). Our previous studies in intestinal-like Caco-2 monolayers showed that PTH rapidly enhanced apical HCO 3 Ϫ secretion through CFTR and Na ϩ -HCO 3 Ϫ cotransporter (NBCe)-1, with an acute response observed within 1-3 min postexposure (early phase) (10,33).…”

Bile deficiency induces changes in intestinal Cl− and HCO3− secretions in mice

“…Ussing chamber experiments were performed as previously described by us (Song et al . ). Briefly, the duodenal and jejunal mucosae were mounted between two chambers.…”

“…The real‐time RT‐PCR analysis was performed according to our previous method (Song et al . ). The expression levels of CFTR and NKCC1 mRNA were normalized to that of β ‐actin and were expressed as a ratio relative to β ‐actin.…”