NOD‐like receptor pyrin domain‐containing‐3 (NLRP3) regulates inflammation‐induced pro‐labor mediators in human myometrial cells

Problem Inflammation plays a major role in preterm birth. Nucleotide‐binding oligomerization domain‐like receptor pyrin domain‐containing‐3 (NLRP3) plays a role in inflammatory diseases. The aims of this study were to determine the effect of term labor on the expression of NLRP3 in human myometrium and the effect of NLRP3 silencing on pro‐labor mediators in myometrial cells. Method of study NLRP3 expression was assessed in myometrium from non‐laboring and laboring women by qRT‐PCR and Western blotting. Human primary myometrial cells were transfected with NLRP3 siRNA (siNLRP3), treated with pro‐inflammatory cytokines and toll‐like receptor (TLR) ligands, and assayed for pro‐inflammatory mediators’ expression. Results NLRP3 expression was higher in myometrium after term spontaneous labor and by TNF, IL1B, fsl‐1, and flagellin. In siNLRP3‐transfected cells, there was a significant decrease in the expression of pro‐inflammatory cytokines (IL1A, IL6), chemokines (CXCL8, CCL2), and adhesion molecules (ICAM1 and VCAM1) stimulated with IL1B, TNF, or TLR ligands; decrease in IL1B‐stimulated PTGS2 and PTGFR mRNA expression and PGF2α release; and increase in TNF‐stimulated myometrial gel shrinkage as assessed by an in vitro cell contraction assay. Conclusion NLRP3 is increased with labor in myometrial, and knockdown of NLRP3 is associated with an attenuation of inflammation‐induced expression of pro‐inflammatory and pro‐labor mediators in human myometrium.