title: CAP37 activation of PKC promotes human corneal epithelial cell chemotaxis.
abstract: OBJECTIVE
  The objective of this study was to elucidate the signaling pathway through which cationic antimicrobial protein of 37 kDa (CAP37) mediates human corneal epithelial cell (HCEC) chemotaxis.
  
  
  METHODS
  Immortalized HCECs were treated with pertussis toxin (10 and 1000 ng/mL), protein kinase C (PKC) inhibitors (calphostin c, 50 nM and Ro-31-8220, 100 nM), phorbol esters (phorbol 12,13-dibutyrate, 200 nM and phorbol 12-myristate 13-acetate, 1 μM) known to deplete PKC isoforms, and siRNAs (400 nM) before a modified Boyden chamber assay was used to determine the effect of these inhibitors and siRNAs on CAP37-directed HCEC migration. PKCδ protein levels, PKCδ-Thr(505) phosphorylation, and PKCδ kinase activity was assessed in CAP37-treated HCECs using immunohistochemistry, Western blotting, and a kinase activity assay, respectively.
  
  
  RESULTS
  Chemotaxis studies revealed that treatment with pertussis toxin, PKC inhibitors, phorbol esters, and siRNAs significantly inhibited CAP37-mediated chemotaxis compared with untreated controls. CAP37 treatment increased PKCδ protein levels and led to PKCδ phosphorylation on residue Thr(505). Direct activation of PKCδ by CAP37 was demonstrated using a kinase activity assay.
  
  
  CONCLUSIONS
  These findings lead us to conclude that CAP37 is an important regulator of corneal epithelial cell migration and mediates its effects through PKCδ.
authors.affiliation: Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma.
authors.forename: Gina L
authors.initials: GL
authors.lastname: Griffith
authors.forename: Robert A
authors.initials: RA
authors.lastname: Russell
authors.forename: Anne
authors.initials: A
authors.lastname: Kasus-Jacobi
authors.forename: Elangovan
authors.initials: E
authors.lastname: Thavathiru
authors.forename: Melva L
authors.initials: ML
authors.lastname: Gonzalez
authors.forename: Sreemathi
authors.initials: S
authors.lastname: Logan
authors.forename: H Anne
authors.initials: HA
authors.lastname: Pereira
mesh_terms: D023181:Antimicrobial Cationic Peptides / Q000378:metabolism*; D001798:Blood Proteins / Q000378:metabolism*; D015153:Blotting, Western; D002352:Carrier Proteins / Q000378:metabolism*; D002478:Cells, Cultured; D002633:Chemotaxis / Q000502:physiology*; D004789:Enzyme Activation; D019573:Epithelium, Corneal / Q000166:cytology / Q000378:metabolism*; D006023:Glycoproteins; D006801:Humans; D007150:Immunohistochemistry; D018613:Microscopy, Confocal; D011493:Protein Kinase C / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: C062991:AZU1 protein, human; D023181:Antimicrobial Cationic Peptides; D001798:Blood Proteins; D002352:Carrier Proteins; D006023:Glycoproteins; D011493:Protein Kinase C
keywords: cationic antimicrobial proteins; inflammation; migration; protein kinase C; signaling