title: Hydroxychloroquine restores trophoblast fusion affected by antiphospholipid antibodies.
abstract: BACKGROUND
  Obstetric antiphospholipid syndrome (APS) is defined by pregnancy complications associated with antiphospholipid antibodies (aPL). The mechanisms of the pathogenic effects of aPL in pregnancy are poorly understood. Toll-like receptors (TLR) have been implicated previously in APS.
  
  
  OBJECTIVE
  The aims of our study were (1) to determine aPL effects on trophoblastic cell fusion and differentiation, (2) to identify which TLR is involved in this process, and (3) to evaluate the efficacy of hydroxychloroquine (HCQ) to counteract the effects of aPL.
  
  
  METHODS
  BeWo cells are a model for trophoblast fusion and differentiation. Fusion index was assessed by immunocytochemical examination, and biochemical differentiation by using ELISA-measured β-human choronic gonadotropin hormone (β-hCG) secretion. We used three types of aPL to study their effect on cell fusion and differentiation: aPL derived from obstetric APS patients and affinity purified and polyclonal rabbit anti-β2-glycoprotein-1 (anti-β2GP1) antibodies. Experiments on fusion were confirmed using primary cytotrophoblastic cells.
  
  
  RESULTS
  All of the types of aPL used decreased the fusion index in BeWo and primary trophoblastic cells (64%, 52%, and 41% for BeWo cells and 67% and 62% for primary cells, respectively), and anti-β2GP1 antibodies decreased hCG secretion in BeWo cells (41%). To block TLR4 antibodies or to abolish TLR4 cell surface expression restored fusion index in both cell types and β-human choronic gonadotropin hormone excretion in BeWo cells. HCQ treatment induced the same effect and decreased TLR4 mRNA (40% and 35%, respectively) and protein expressions (62% and 42%, respectively) in BeWo cells.
  
  
  CONCLUSIONS
  Anti-β2GP1 antibodies decrease trophoblastic differentiation via TLR4. This effect is restored by HCQ, suggesting its therapeutic interest in APS pregnancies.
authors.affiliation: Laboratory of Hormonology, Maternity, Geneva University Hospitals and Faculty of Medicine of Geneva, Geneva, Switzerland; Angiology and Haemostasis Division, Geneva University Hospitals and Faculty of Medicine of Geneva, Geneva, Switzerland.
authors.forename: T
authors.initials: T
authors.lastname: Marchetti
authors.forename: A
authors.initials: A
authors.lastname: Ruffatti
authors.forename: C
authors.initials: C
authors.lastname: Wuillemin
authors.forename: P
authors.initials: P
authors.lastname: de Moerloose
authors.forename: M
authors.initials: M
authors.lastname: Cohen
mesh_terms: D000328:Adult; D000906:Antibodies / Q000494:pharmacology; D017152:Antibodies, Antiphospholipid / Q000097:blood*; D016736:Antiphospholipid Syndrome / Q000097:blood*; D002454:Cell Differentiation / Q000187:drug effects; D002459:Cell Fusion; D002460:Cell Line; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000378:metabolism; D005260:Female; D006801:Humans; D006886:Hydroxychloroquine / Q000494:pharmacology*; D011247:Pregnancy; D012333:RNA, Messenger / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D014327:Trophoblasts / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D053482:beta 2-Glycoprotein I / Q000276:immunology / Q000378:metabolism
chemical_list: D000906:Antibodies; D017152:Antibodies, Antiphospholipid; D018997:Chorionic Gonadotropin, beta Subunit, Human; D012333:RNA, Messenger; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; D053482:beta 2-Glycoprotein I; D006886:Hydroxychloroquine
keywords: Toll-like receptor; antiphospholipid antibody syndrome; beta 2-Glycoprotein I; hydroxychloroquine; placenta; pregnancy