title: Antimicrobial peptide LL37 promotes vascular endothelial growth factor-A expression in human periodontal ligament cells.
abstract: OBJECTIVE
  LL37, originally found in the innate immune system, is a robust antimicrobial peptide. LL37 exhibits multiple bio-functions in various cell types, such as migration, cytokine production, apoptosis, and angiogenesis besides its antimicrobial activity Periodontal ligament (PL) cells play a pivotal role in periodontal tissue regeneration. Based on these findings, we hypothesized that LL37 can regulate PL cell function to promote regeneration of periodontal tissue. To prove this hypothesis, we investigated the effect of LL37 on the potent angiogenic inducer vascular endothelial growth factor (VEGF) expression in cultures of human PL (HPL) cells because neovascularization is indispensable for the progress of tissue regeneration. Moreover, we investigated the signaling cascade associated with LL37-induced VEGF expression.
  
  
  METHODS
  HPL cells were treated with synthesized LL37 in the presence or absence of PD98059, a MEK-ERK inhibitor, or PDTC, an NF-κB inhibitor. VEGF expression levels were assessed by real-time polymerase chain reaction analysis and an enzyme-linked immunoassay. Phosphorylation levels of ERK1/2 or NF-κB p65 were determined by Western blotting.
  
  
  RESULTS
  LL37 upregulated VEGF-A expression at the mRNA and protein levels in HPL cells, while VEGF-B mRNA expression was not affected. Both ERK and NF-κB inhibitors clearly abrogated the increase in VEGF-A levels induced by LL37 in HPL cells. Importantly, LL37 increased phosphorylated levels of ERK1/2 and NF-κB p65 in HPL cells.
  
  
  CONCLUSIONS
  LL37 induces VEGF-A production in HPL cells via ERK and NF-κB signaling cascades, which may result in angiogenesis, thereby contributing to periodontal regeneration.
authors.affiliation: Department of Periodontal Medicine, Applied Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kittaka
authors.forename: H
authors.initials: H
authors.lastname: Shiba
authors.forename: M
authors.initials: M
authors.lastname: Kajiya
authors.forename: K
authors.initials: K
authors.lastname: Ouhara
authors.forename: K
authors.initials: K
authors.lastname: Takeda
authors.forename: K
authors.initials: K
authors.lastname: Kanbara
authors.forename: T
authors.initials: T
authors.lastname: Fujita
authors.forename: H
authors.initials: H
authors.lastname: Kawaguchi
authors.forename: H
authors.initials: H
authors.lastname: Komatsuzawa
authors.forename: H
authors.initials: H
authors.lastname: Kurihara
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D054804:Cathelicidins / Q000494:pharmacology*; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects; D019950:Mitogen-Activated Protein Kinase 1 / Q000032:analysis; D016328:NF-kappa B / Q000032:analysis / Q000037:antagonists & inhibitors; D018919:Neovascularization, Physiologic / Q000187:drug effects; D010513:Periodontal Ligament / Q000166:cytology / Q000187:drug effects*; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011759:Pyrrolidines / Q000494:pharmacology; D012038:Regeneration / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects; D013859:Thiocarbamates / Q000494:pharmacology; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors / Q000187:drug effects*; D019892:eIF-2 Kinase / Q000032:analysis; D048051:p38 Mitogen-Activated Protein Kinases / Q000032:analysis
chemical_list: D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D054804:Cathelicidins; D005419:Flavonoids; D016328:NF-kappa B; D047428:Protein Kinase Inhibitors; D011759:Pyrrolidines; D013859:Thiocarbamates; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; C020972:pyrrolidine dithiocarbamic acid; D019892:eIF-2 Kinase; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048051:p38 Mitogen-Activated Protein Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one