title: The EP3 receptor stimulates ceramide and diacylglycerol release and inhibits growth of primary keratinocytes.
abstract: Primary human keratinocytes (PHKs) are known to express the EP3 subtype of prostaglandin E2 receptor. To better understand the role of EP3 receptors in regulating epidermal function, we characterized their expression, localization, and signaling effects in human skin. Three different splice variants of the EP3 receptor (EP3A1, EP3C, and EP3D) were found to be expressed. Immunohistochemical analysis of human skin demonstrated that EP3 receptors were most prominently expressed in the basal and lower spinous layers of the epidermis. The EP3 receptor agonist sulprostone was then used to examine EP3 receptor-dependent keratinocyte signaling pathways and functional effects. We observed that sulprostone inhibits keratinocyte growth at doses between 0.02 and 2 nM and induces sn-1,2-diacylglycerol (DAG) and ceramide production. Concurrent expression of the cell-cycle inhibitory protein p21WAF1 also occurred. These data suggest that EP3 receptors produce epidermal growth inhibition through the action of DAG and ceramide second messengers.
authors.affiliation: Department of Pathology, Indiana University School of Medicine, Indianapolis, IN 46122, USA. rkonger@iupui.edu
authors.forename: Raymond L
authors.initials: RL
authors.lastname: Konger
authors.forename: Sabine
authors.initials: S
authors.lastname: Brouxhon
authors.forename: Steven
authors.initials: S
authors.lastname: Partillo
authors.forename: JoAnne
authors.initials: J
authors.lastname: VanBuskirk
authors.forename: Alice P
authors.initials: AP
authors.lastname: Pentland
mesh_terms: D015153:Blotting, Western; D049109:Cell Proliferation; D002478:Cells, Cultured; D002518:Ceramides / Q000378:metabolism*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D004274:DNA, Recombinant; D004075:Diglycerides / Q000378:metabolism*; D004817:Epidermis / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D015603:Keratinocytes / Q000166:cytology* / Q000378:metabolism*; D018078:Receptors, Prostaglandin E / Q000235:genetics / Q000502:physiology*; D058308:Receptors, Prostaglandin E, EP3 Subtype; D014018:Tissue Distribution
chemical_list: C011439:1,2-diacylglycerol; C493956:CDKN1A protein, human; D002518:Ceramides; D050759:Cyclin-Dependent Kinase Inhibitor p21; D004274:DNA, Recombinant; D004075:Diglycerides; C545647:PTGER3 protein, human; D018078:Receptors, Prostaglandin E; D058308:Receptors, Prostaglandin E, EP3 Subtype