Abstract
Purpose :
Formation of inflammasome complexes are required for maturation and release of early initiator of immune responses, interleukin (IL)-1β. The aim of the present study was to investigate whether ultraviolet (UV) irradiation can activate nod-like receptor protein 3 (NLRP3) inflammasomes and further induce secretion of IL-1β in human retinal pigment epithelial (ARPE-19) cells in vitro. In addition, the role of potassium efflux as an upstream mechanism of inflammasome activation was explored in the present study.
Methods :
ARPE-19 cells were primed with IL-1α and treated with potassium chloride prior to irradiation of UV light (wavelength of 290-320 nm). For siRNA experiments, subconfluent cell layers were transfected with NLRP3 siRNA prior to priming signal. Secretion of IL-1β and cleaved caspase-1 as well as levels of NLRP3 were detected by ELISA assay. All data was analyzed by using Mann-Whitney U-test.
Results :
IL-1α primed ARPE-19 cells upon UV irradiation induced secretion of IL-1β (p<0.001), which was further declined by preventing potassium efflux during the UV exposure (p<0.001). Furthermore, significantly increased levels of NLRP3 and cleaved caspase-1 were found from cell culture medium after UV exposure (both p<0.001), indicating that inflammasome components were released out from the cells after inflammasome activation. In addition, NLRP3 siRNA revealed decreased release of IL-1β compared to negative siRNA control (p<0.01).
Conclusions :
Our data shows that UV activates NLRP3 inflammasomes, which further triggers the secretion of IL-1β in ARPE-19 cells. In addition, potassium efflux seems to be involved in UV induced inflammasome activation.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.