Forskolin inhibited the secretion of interleukin-1β in activated human THP-1 macrophages

Abstract

Objective To investigate the effects of Forskolin on the activation of nucleotide-binding oligomerization domain like receptor family, pyrin domain-containing 3(NLRP-3) inflammasome and the secretion of interleukin-1β(IL-1β) in activated human THP-1 macrophages, which can provide evidence for clinical treatment of inflammatory diseases in children. Methods Human monocyte cell line THP-1 cells were induced to differentiate into macrophages by Phorbol-12-myristate-13-acetate(PMA), and Forskolin(10, 50, 100 μmol/L) stimulated activated macrophages by nigericin.The mRNA of the inflammasome markers NLRP-3, IL-1β and Caspase-1 were detected by real-time quantitative polymerase chain reaction(qPCR) method.The protein of NLRP-3, pro-IL-1β, pro-Caspase-1 and Caspase-1 were detected by Western blot.The secretion of inflammatory cytokines IL-1β was detected by enzyme-linked immuno-sorbent assay(ELISA). Results Nigericin activated the cells and the mRNA expression of NLRP-3, IL-1β and Caspase-1 increased by 7.59 times(P 0.05). Western blot showed that Forskolin also had no effect on the protein expression of pro-Caspase-1 and pro-IL-1β in activated THP-1 macrophages(P>0.05), but the expression of NLRP-3 and Caspase-1 decreased significantly (P<0.001). The results of ELISA showed that the IL-1β secretion increased from basal 584.0 nmol/L to activated 2 695.6 nmol/L(t=16.031 1, P<0.001) on THP-1 macrophages by nigericin, but Forskolin(10, 50, 100 μmol/L) reduced it to 1 858.4 nmol/L(t=5.365 5, P<0.001), 1 467.9 nmol/L(t=8.047 5, P<0.001) and 1 246.7 nmol/L(t=10.199 0, P<0.001) on the activated THP-1 macrophages. Conclusions Forskolin can not affect the expression of pro-cytokines at the gene transcription and protein translation levels in activated THP-1 cells, but inhibit the secretion of inflammatory cytokines IL-1β, so as to inhibit inflammatory response, which can be used to treat pediatric inflammatory diseases caused by IL-1β. Key words: Inflammation; Forskolin; Macrophage; Inflammasome; Interleukin-1β