title: A novel signaling pathway of tissue kallikrein in promoting keratinocyte migration: activation of proteinase-activated receptor 1 and epidermal growth factor receptor.
abstract: Biological functions of tissue kallikrein (TK, KLK1) are mainly mediated by kinin generation and subsequent kinin B2 receptor activation. In this study, we investigated the potential role of TK and its signaling pathways in cultured human keratinocyte migration and in a rat skin wound healing model. Herein, we show that TK promoted cell migration and proliferation in a concentration- and time-dependent manner. Inactive TK or kinin had no significant effect on cell migration. Interestingly, cell migration induced by active TK was not blocked by icatibant or L-NAME, indicating an event independent of kinin B2 receptor and nitric oxide formation. TK's stimulatory effect on cell migration was inhibited by small interfering RNA for proteinase-activated receptor 1 (PAR(1)), and by PAR(1) inhibitor. TK-induced migration was associated with increased phosphorylation of epidermal growth factor receptor (EGFR) and extracellular signal-regulated kinase (ERK), which was blocked by inhibition of protein kinase C (PKC), Src, EGFR and ERK. TK-induced cell migration and EGFR phosphorylation were blocked by metalloproteinase (MMP) inhibitor, heparin, and antibodies against EGFR external domain, heparin-binding EGF-like growth factor (HB-EGF) and amphiregulin (AR). Local application of TK promoted skin wound healing in rats, whereas icatibant and EGFR inhibitor blocked TK's effect. Skin wound healing was further delayed by aprotinin and neutralizing TK antibody. This study demonstrates a novel role of TK in skin wound healing and uncovers new signaling pathways mediated by TK in promoting keratinocyte migration through activation of the PAR(1)-PKC-Src-MMP pathway and HB-EGF/AR shedding-dependent EGFR transactivation.
authors.affiliation: Department of Biochemistry and Molecular Biology, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425-2211, USA.
authors.forename: Lin
authors.initials: L
authors.lastname: Gao
authors.forename: Lee
authors.initials: L
authors.lastname: Chao
authors.forename: Julie
authors.initials: J
authors.lastname: Chao
mesh_terms: D000818:Animals; D002465:Cell Movement / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D015603:Keratinocytes / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology*; D007705:Kinins / Q000378:metabolism; D008024:Ligands; D020782:Matrix Metalloproteinases / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000378:metabolism; D051381:Rats; D043782:Receptor, Bradykinin B2 / Q000378:metabolism; D044463:Receptor, PAR-1 / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D012867:Skin / Q000187:drug effects / Q000473:pathology; D020840:Tissue Kallikreins / Q000494:pharmacology*; D015533:Transcriptional Activation / Q000187:drug effects / Q000235:genetics; D014945:Wound Healing / Q000187:drug effects
chemical_list: D007705:Kinins; D008024:Ligands; D043782:Receptor, Bradykinin B2; D044463:Receptor, PAR-1; D009569:Nitric Oxide; D066246:ErbB Receptors; D016392:Proto-Oncogene Proteins pp60(c-src); D011493:Protein Kinase C; D048049:Extracellular Signal-Regulated MAP Kinases; D020840:Tissue Kallikreins; D020782:Matrix Metalloproteinases