AQP3 mediates autophagy through SIRT1/p62 signal to alleviate intestinal epithelial cell damage caused by sepsis.

Abstract

Background: Autophagy damage will aggravate intestinal damage caused by sepsis. Studies have shown that the activation of AQP3 and SIRT1 signals can reduce the inflammatory response of sepsis. However, their role and mechanism in intestinal injury in the late stage of sepsis are not deeply studied.

Objective: To explore whether AQP3 can mediate autophagy by regulating the SIRT1/P62 signaling pathway to alleviate intestinal epithelial cell damage caused by sepsis.

Methods: Caco-2 cells were transfected with plasmid to overexpress AQP3. Western blot and RT-qPCR were used to detect the expression of cell protein, ELISA was used to detect the level of cytokines, DCFH-DA probe was added to quantify the ROS level, and the integrity of cell barrier was evaluated by measuring the transepithelial resistance (TEER). The autophagy levels were observed by MDC staining, and the levels of ZO-1 and Occludin were detected by immunofluorescence.

Results: AQP3 was down-regulated in the Caco-2 cell injury model induced by LPS in vitro. Overexpression of AQP3 inhibited the production of inflammatory factors and ROS, thus relieving LPS-induced intestinal epithelial cell damage; restored the TEER of cells; up-regulated the expression of claudin-1, TJP-1, Occludin, and ZO-1, thus alleviating the cell barrier injury; increased autophagy bodies in cells; and increased the expression of Beclin1 and the ratio of LC3-II/LC3-I while inhibiting the expression of p62, thus restoring the autophagy level of cells. However, autophagy inhibitor 3-MA and SIRT1 inhibitor EX 527 offset these effects of AQP3 overexpression.

Conclusion: AQP3 regulated the autophagy level of Caco-2 cells induced by LPS through SIRT1/p62 signal and relieved intestinal epithelial cell damage caused by sepsis.