Exogenous Gas6 attenuates silica-induced inflammation on differentiated THP-1 macrophages

Growth arrest specific 6 (Gas6) has been reported to be related to the modulation of innate immunity. To investigate the potential effect of Gas6 on the regulation of inflammations induced by silica, differentiated THP-1 macrophages were exposed to different concentrations of silica for 6 hand 24 h. Additionally, silica activated macrophages were treated with Gas6 antibody and Gas6 respectively. Expression levels of Gas6 and inflammatory cytokines (TNF-alpha, IL-1 beta and IL-6) were measured. Our results showed that both cell viability and Gas6 expression were suppressed by silica in dose-dependent manners. After pretreatment with Gas6 antibody, silica induced a significant decrease in cell viability and a significant increase in inflammatory cytokines at two time points. Moreover, addition of Gas6 significantly suppressed silica induced TNF-alpha, IL-1 beta and IL-6 levels in negative dose-dependent manners, not only in mRNA levels but also in protein levels. Our results suggested that exogenous Gas6 might attenuate inflammations induced by silica on macrophages. (C) 2016 Elsevier B.V. All rights reserved.