50 DAMPs enhance inflammation in monocytes from pregnant women with preeclampsia

Abstract

Introduction Preeclampsia (PE) is the major cause of morbidity and mortality both maternal and fetal. Plasma of these pregnant women contains high levels of molecular structures associated with stress and cell death, as hyaluronan (HA) and heat shock proteins (HSP) which can interact with receptors present on innate immune cells and activate intracellular complexes called inflammasomes. Objective This study evaluated the involvement of the DAMPs, HA and HSP70, in inflammasomes activation and cytokines production by monocytes from pregnant women with PE. Methods It was studied 20 pregnant women with PE, 20 normotensive (NT) pregnant women and 20 non-pregnant (NP) women. The collected blood was centrifuged and plasma was stored at −80 °C for measurement of DAMPs (HA, HSP70 and HMGB1). Monocytes obtained from peripheral blood were incubated in the presence or absence of DAMPs (HA and HSP70) and the supernatant obtained after 18 h of culture was used to quantify the cytokines IL-1 β , IL-18 and TNF- α by ELISA. The presence of inflammasomes was assessed by the gene expression of NLRP1, NLRP3, caspase-1, IL-1 β , IL-18, HMGB1 and TNF- α by RT-qPCR, after 4 h of culture. The results were analyzed using non-parametric tests at 5% significance level. Results Plasma levels of HA, HSP70 and HMGB1 were elevated in women with PE compared to NT and NP groups. Endogenous gene expression of NLRP1, NLRP3, caspase-1, IL-1 β , TNF- α and HMGB1 were significantly enhanced in pregnant women with PE than NT and NP groups. The stimulation of monocytes with HA induced an increase mRNA expression of NLRP1, NLRP3, caspase-1, IL-1 β , TNF- α and HMGB1 while HSP70 just increased TNF- α mRNA expression. Regarding the endogenous cytokines production, IL-1 β was higher in pregnant women with PE compared to NT and NP groups, while IL-18 and TNF- α were increased only in PE group when compared to NT group. All groups showed an increase of IL-1 β when stimulated with HA. The levels of IL-1 β and TNF- α were elevated when stimulated with HSP70 in all studied groups. Conclusion The greater endogenous gene expression of NLRP1, NLRP3, caspase-1, IL-1 β , HMGB1 and TNF- α in preeclamptic women confirms the activated state of monocytes in this disease. The higher gene expression of the inflammasomes, HMGB1 and IL-1 β induced by HA suggests that this DAMP can contribute to the activation of this complex in monocytes from pregnant women with PE. These results suggest the involvement of these DAMPs in the inflammatory process observed in PE. Financial support: 2013/00534-5 and 2012/24697-8.