title: Chemoattractant receptor homologous to the T helper 2 cell (CRTH2) is not expressed in human amniocytes and myocytes.
abstract: BACKGROUND
  15-deoxy-Δ 12,14- Prostaglandin J2 (15dPGJ2) inhibits Nuclear factor kappa B (NF-κB) in human myocytes and amniocytes and delays inflammation induced preterm labour in the mouse. 15dPGJ2 is a ligand for the Chemoattractant Receptor Homologous to the T helper 2 cell (CRTH2), a G protein-coupled receptor, present on a subset of T helper 2 (Th2) cells, eosinophils and basophils. It is the second receptor for Prostaglandin D2, whose activation leads to chemotaxis and the production of Th2-type interleukins. The cellular distribution of CRTH2 in non-immune cells has not been extensively researched, and its identification at the protein level has been limited by the lack of specific antibodies. In this study we explored the possibility that CRTH2 plays a role in 15dPGJ2-mediated inhibition of NF-κB and would therefore represent a novel small molecule therapeutic target for the prevention of inflammation induced preterm labour.
  
  
  METHODS
  The effect of a small molecule CRTH2 agonist on NF-κB activity in human cultured amniocytes and myocytes was assessed by detection of p65 and phospho-p65 by immunoblot. Endogenous CRTH2 expression in amniocytes, myocytes and peripheral blood mononuclear cells (PBMCs) was examined by PCR, western analysis and flow cytometry, with amniocytes and myocytes transfected with CRTH2 acting as a positive control in flow cytometry studies.
  
  
  RESULTS
  The CRTH2 agonist had no effect on NF-κB activity in amniocytes and myocytes. Although CRTH2 mRNA was detected in amniocytes and myocytes, CRTH2 was not detectable at the protein level, as demonstrated by western analysis and flow cytometry. 15dPGJ2 inhibited phospho-65 in PBMC'S, however the CRTH2 antagonist was not able to attenuate this effect. In conclusion, CRTH2 is not expressed on human amniocytes or myocytes and plays no role in the mechanism of 15dPGJ2-mediated inhibition of NF-κB.
authors.affiliation: Parturition Research Group, Department of Surgery and Cancer, Imperial College London, London, England. l.sykes@imperial.ac.uk
authors.forename: Lynne
authors.initials: L
authors.lastname: Sykes
authors.forename: Yun
authors.initials: Y
authors.lastname: Lee
authors.forename: Shirin
authors.initials: S
authors.lastname: Khanjani
authors.forename: David A
authors.initials: DA
authors.lastname: Macintyre
authors.forename: Xiao J
authors.initials: XJ
authors.lastname: Yap
authors.forename: Sathana
authors.initials: S
authors.lastname: Ponnampalam
authors.forename: Tiong Ghee
authors.initials: TG
authors.lastname: Teoh
authors.forename: Phillip R
authors.initials: PR
authors.lastname: Bennett
mesh_terms: D000653:Amniotic Fluid / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D053583:Interleukin-1beta / Q000494:pharmacology; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000378:metabolism; D032342:Muscle Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism; D010455:Peptides / Q000494:pharmacology; D011247:Pregnancy; D015230:Prostaglandin D2 / Q000031:analogs & derivatives / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011971:Receptors, Immunologic / Q000819:agonists / Q000235:genetics* / Q000378:metabolism*; D011982:Receptors, Prostaglandin / Q000819:agonists / Q000235:genetics* / Q000378:metabolism*
chemical_list: C477819:15-deoxyprostaglandin J2; D053583:Interleukin-1beta; D016328:NF-kappa B; D010455:Peptides; D012333:RNA, Messenger; D011971:Receptors, Immunologic; D011982:Receptors, Prostaglandin; C045865:PYL(a); D015230:Prostaglandin D2; C036293:prostaglandin D2 receptor