title: Keratinocyte outgrowth from human skin explant cultures is dependent upon p38 signaling.
abstract: Organ culture of skin is known to recapitulate several early events in the process of wound healing. Here we investigate the function of p38 kinase signaling as a regulator of keratinocyte behavior in human skin organ culture. We first show that skin organ culture recapitulates the transition from migration to proliferation that is known to characterize the reepithelialization process. We next show that inhibition of p38 markedly impairs the formation of keratinocyte outgrowth in human skin explant cultures, as well as the migration of keratinocytes in an in vitro wound assay. In contrast, the marked induction of mRNA encoding the ErbB ligand heparin-binding epidermal growth factor-like growth factor, known to occur after skin wounding, was not blocked by inhibition of p38. As assessed by immunoblotting, phosphorylation of p38 was limited and was not increased between 0 and 7 days of organ culture. Our results show the sensitivity of reepithelialization to inhibition by p38 and suggest that p38 acts primarily during the migration phase of this process. These data also indicate that autocrine heparin-binding epidermal growth factor expression is not regulated by p38.
authors.affiliation: Department of Dermatology, University of Michigan Medical Center, 1500 E. Medical Center Drive, Ann Arbor, MI 48109-0932, USA.
authors.forename: Stefan W
authors.initials: SW
authors.lastname: Stoll
authors.forename: Sanjay
authors.initials: S
authors.lastname: Kansra
authors.forename: James T
authors.initials: JT
authors.lastname: Elder
mesh_terms: D066258:Amphiregulin; D018929:Cell Culture Techniques; D002455:Cell Division / Q000187:drug effects; D066255:EGF Family of Proteins; D004815:Epidermal Growth Factor / Q000235:genetics; D015870:Gene Expression / Q000187:drug effects; D006023:Glycoproteins / Q000235:genetics; D066257:Heparin-binding EGF-like Growth Factor; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics; D015603:Keratinocytes / Q000187:drug effects / Q000502:physiology*; D020935:MAP Kinase Signaling System / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*; D009924:Organ Culture Techniques; D010766:Phosphorylation / Q000187:drug effects; D011725:Pyridines / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: C587848:AREG protein, human; D066258:Amphiregulin; D066255:EGF Family of Proteins; D006023:Glycoproteins; C587883:HBEGF protein, human; D066257:Heparin-binding EGF-like Growth Factor; D007093:Imidazoles; D036341:Intercellular Signaling Peptides and Proteins; D011725:Pyridines; D004815:Epidermal Growth Factor; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C090942:4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)imidazole