Published online Mar 7, 2022. doi: 10.3748/wjg.v28.i9.918
Peer-review started: November 10, 2021
First decision: December 3, 2021
Revised: December 14, 2021
Accepted: January 22, 2022
Article in press: January 22, 2022
Published online: March 7, 2022
Processing time: 112 Days and 21.7 Hours
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).
To investigate the effects of CFTR on I/R-induced intestinal apoptosis and its underlying molecular mechanisms.
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.
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.
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.
Core Tip: 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. In our paper, our data demonstrate that cystic fibrosis transmembrane conductance regulator (CFTR) is downregulated in hypoxia/reoxygenation (H/R)-treated Caco2 cells, and overexpression of CFTR protects Caco2 cells from H/R-induced apoptosis. Additionally, CFTR is involved in inhibiting H/R-induced apoptosis, and it inhibits apoptosis through PI3K/AKT/NF-κB signaling pathway. In all, this work suggests that overexpression of CFTR attenuates H/R-induced apoptosis through PI3K/AKT/NF-κB signaling pathway in H/R-treated Caco2 cells.