Cystic fibrosis transmembrane conductance regulator prevents ischemia/reperfusion induced intestinal apoptosis via inhibiting PI3K/AKT/NF-κB pathway

Abstract

Background: Intestinal ischemia/reperfusion (I/R) injury is a fatal syndrome that occurs under many clinical scenarios. The apoptosis of intestinal cells caused by ischemia can cause cell damage and provoke systemic dysfunction during reperfusion. However, the mechanism of I/R-induced apoptosis remains unclear. Cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-activated chloride channel. Few researchers have paid attention to its role in intestinal I/R injury, or the relationship between CFTR and intestinal apoptosis induced by hypoxia/reoxygenation (H/R).

Aim: To investigate the effects of CFTR on I/R-induced intestinal apoptosis and its underlying molecular mechanisms.

Methods: An intestinal I/R injury model was established in mice with superior mesenteric artery occlusion, and Caco2 cells were subjected to H/R for the simulation of I/R in vivo.

Results: The results suggested that CFTR overexpression significantly increased the Caco2 cell viability and decreased cell apoptosis induced by the H/R. Interestingly, we found that the translocation of p65, an NF-κB member, from the cytoplasm to the nucleus after H/R treatment can be reversed by the overexpression of CFTR, the NF-κB P65 would return from the nucleus to the cytoplasm as determined by immunostaining. We also discovered that CFTR inhibited cell apoptosis in the H/R-treated cells, and this effect was significantly curbed by the NF-κB activator BA, AKT inhibitor GSK690693 and the PI3K inhibitor LY294002. Moreover, we demonstrated that CFTR overexpression could reverse the decreased PI3K/AKT expression induced by the I/R treatment in vivo or H/R treatment in vitro.

Conclusion: The results of the present study indicate that the overexpression of CFTR protects Caco2 cells from H/R-induced apoptosis; furthermore, it also inhibits H/R-induced apoptosis through the PI3K/AKT/NF-κB signaling pathway in H/R-treated Caco2 cells and intestinal tissues.

Keywords: Apoptosis; Caco2 cells; Cystic fibrosis transmembrane conductance regulator; Hypoxia/reoxygenation; Intestinal ischemia-reperfusion injury; PI3K/AKT/NF-κB.