title: HB-EGF synthesis and release induced by cholesterol depletion of human epidermal keratinocytes is controlled by extracellular ATP and involves both p38 and ERK1/2 signaling pathways.
abstract: The heparin-binding EGF-like growth factor (HB-EGF) is an autocrine/paracrine keratinocyte growth factor, which binds to the epidermal growth factor (EGF) receptor family and plays a critical role during the re-epithelialization of cutaneous wound by stimulating the keratinocytes proliferation and migration. In this study, cellular stressing condition in autocrine cultures of human keratinocytes was induced by cholesterol depletion using methyl-beta-cyclodextrin (MβCD). MβCD treatment induces the expression and the release of HB-EGF. By analysis of the culture media, large amounts of cellular ATP were measured particularly after 1 h of MβCD treatment. To investigate whether ATP contributes to the expression of HB-EGF, the nonhydrolyzable ATP analogue, ATP-γ-S, was used to mimic the extracellular ATP released. We report that keratinocytes stimulated with ATP-γ-S induce HB-EGF expression and activate EGFR and ERK1/2. Using an antagonist of P2 purinergic receptors, we demonstrate that HB-EGF synthesis induced by lipid rafts disruption is dependent on ATP interaction with P2 purinergic receptors. Moreover, our data suggest that both MAPKs p38 and ERK1/2 are involved together or independently in the regulation of HB-EGF gene expression. These findings provide new insight into the signaling pathway by which HB-EGF is expressed after lipid rafts disruption. In summary, after lipid raft disruption, keratinocytes release large amount of extracellular ATP. ATP induces HB-EGF synthesis and release by interacting with the P2 purinergic receptor and through p38 and ERK1/2 signaling in response to a challenging environment. A release of ATP acts as an early stress response in keratinocytes.
authors.affiliation: Cell and Tissue Laboratory, URPHYM, Narilis, University of Namur (FUNDP), Namur, Belgium.
authors.forename: Séverine
authors.initials: S
authors.lastname: Giltaire
authors.forename: Sylviane
authors.initials: S
authors.lastname: Lambert
authors.forename: Yves
authors.initials: Y
authors.lastname: Poumay
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D002478:Cells, Cultured; D002784:Cholesterol / Q000172:deficiency* / Q000378:metabolism; D000078404:Epidermal Cells; D066246:ErbB Receptors / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D066257:Heparin-binding EGF-like Growth Factor; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000096:biosynthesis* / Q000378:metabolism*; D015603:Keratinocytes / Q000187:drug effects / Q000201:enzymology*; D020935:MAP Kinase Signaling System / Q000187:drug effects; D021962:Membrane Microdomains / Q000187:drug effects / Q000378:metabolism; D008954:Models, Biological; D011485:Protein Binding / Q000187:drug effects; D011983:Receptors, Purinergic / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
chemical_list: C587883:HBEGF protein, human; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D011983:Receptors, Purinergic; C022571:adenosine 5'-O-(3-thiotriphosphate); D000255:Adenosine Triphosphate; D002784:Cholesterol; D066246:ErbB Receptors; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases