title: IL-1 beta but not the NALP3 inflammasome is an important determinant of endothelial cell responses to necrotic/dangerous trophoblastic debris.
abstract: BACKGROUND
  Necrotic but not apoptotic trophoblastic debris can induce endothelial cell activation but the mechanism by which endothelial cells distinguish apoptotic from necrotic debris is unclear. The NALP3 inflammasome is a pattern recognition receptor that macrophages employ to recognise "danger signals" in necrotic cell corpses. In this study, we hypothesized that endothelial cells can identify and respond to necrotic trophoblastic debris via the NALP3 inflammasome.
  
  
  METHODS
  The effect of trophoblastic debris on endothelial expression of NALP3 inflammasome components was investigated using qRT-PCR, immunoassays and fluorescent caspase 1 activity assay. IL-1β in was quantified by ELISA. Endothelial cell activation was measured by cell surface ICAM expression and monocytes adhesion assay.
  
  
  RESULTS
  The NALP3 inflammasome was expressed in resting vascular endothelial cells and is involved in endothelial response to danger signals. However, exposure to necrotic trophoblastic debris did not significantly alter the expression of any of the three components of the NALP3 inflammasome at the mRNA level, nor was caspase-1 activation increased. Conditioned media from endothelial cells exposed to necrotic trophoblastic debris contained elevated levels of IL-1β which was derived from the necrotic debris and which contributed to endothelial cell activation.
  
  
  CONCLUSIONS
  Necrotic trophoblastic debris induced endothelial cell activation through the IL-1β/IL-1R pathway. However, the NALP3 inflammasome in endothelial cells was not involved in this process.
authors.affiliation: Department of Obstetrics and Gynaecology, University of Auckland, New Zealand. Electronic address: j.wei@auckland.ac.nz.
authors.forename: J
authors.initials: J
authors.lastname: Wei
authors.affiliation: Department of Obstetrics and Gynaecology, University of Auckland, New Zealand.
authors.forename: Q
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Department of Obstetrics and Gynaecology, University of Auckland, New Zealand.
authors.forename: J L
authors.initials: JL
authors.lastname: James
authors.affiliation: Department of Obstetrics and Gynaecology, University of Auckland, New Zealand.
authors.forename: P R
authors.initials: PR
authors.lastname: Stone
authors.affiliation: Department of Obstetrics and Gynaecology, University of Auckland, New Zealand.
authors.forename: L W
authors.initials: LW
authors.lastname: Chamley
mesh_terms: D002352:Carrier Proteins / Q000378:metabolism*; D020170:Caspase 1 / Q000378:metabolism; D002460:Cell Line; D042783:Endothelial Cells / Q000378:metabolism*; D005260:Female; D006801:Humans; D058847:Inflammasomes / Q000378:metabolism*; D053583:Interleukin-1beta / Q000378:metabolism*; D009000:Monocytes / Q000378:metabolism; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D009336:Necrosis / Q000378:metabolism; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D015398:Signal Transduction / Q000502:physiology; D014327:Trophoblasts / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D058847:Inflammasomes; D053583:Interleukin-1beta; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C453881:NLRP3 protein, human; D020170:Caspase 1
keywords: Endothelial cells; IL-1 beta; NALP3 inflammasome; Placenta; Trophoblastic debris; Vesicles/particles