title: Prostaglandin E receptor subtype EP3 expression in human conjunctival epithelium and its changes in various ocular surface disorders.
abstract: BACKGROUND
  In our earlier genome-wide association study on Stevens-Johnson Syndrome (SJS) and its severe variant, toxic epidermal necrolysis (TEN), we found that in Japanese patients with these severe ocular surface complications there was an association with prostaglandin E receptor 3 (EP3) gene (PTGER3) polymorphisms. We also reported that EP3 is dominantly expressed in the ocular surface-, especially the conjunctival epithelium, and suggested that EP3 in the conjunctival epithelium may down-regulate ocular surface inflammation. In the current study we investigated the expression of EP3 protein in the conjunctiva of patients with various ocular surface diseases such as SJS/TEN, chemical eye burns, Mooren's ulcers, and ocular cicatricial pemphigoid (OCP).
  
  
  RESULTS
  Conjunctival tissues were obtained from patients undergoing surgical reconstruction of the ocular surface due to SJS/TEN, chemical eye burns, and OCP, and from patients with Mooren's ulcers treated by resection of the inflammatory conjunctiva. The controls were nearly normal human conjunctival tissues acquired at surgery for conjunctivochalasis. We performed immunohistological analysis of the EP3 protein and evaluated the immunohistological staining of EP3 protein in the conjunctival epithelium of patients with ocular surface diseases. EP3 was expressed in the conjunctival epithelium of patients with chemical eye burns and Mooren's ulcer and in normal human conjunctival epithelium. However, it was markedly down-regulated in the conjunctival epithelium of SJS/TEN and OCP patients.
  
  
  CONCLUSIONS
  We posit an association between the down-regulation of EP3 in conjunctival epithelium and the pathogenesis and pathology of SJS/TEN and OCP, and suggest a common mechanism(s) in the pathology of these diseases. The examination of EP3 protein expression in conjunctival epithelium may aid in the differential diagnosis of various ocular surface diseases.
authors.affiliation: Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan. mueta@koto.kpu-m.ac.jp
authors.forename: Mayumi
authors.initials: M
authors.lastname: Ueta
authors.forename: Chie
authors.initials: C
authors.lastname: Sotozono
authors.forename: Norihiko
authors.initials: N
authors.lastname: Yokoi
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Inatomi
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kinoshita
mesh_terms: D003228:Conjunctiva / Q000166:cytology*; D003229:Conjunctival Diseases; D004848:Epithelium / Q000378:metabolism*; D005126:Eye Burns / Q000378:metabolism; D005128:Eye Diseases / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D058308:Receptors, Prostaglandin E, EP3 Subtype / Q000378:metabolism*
chemical_list: D058308:Receptors, Prostaglandin E, EP3 Subtype