title: Human corneal epithelial cells produce antimicrobial peptides LL-37 and β-defensins in response to heat-killed Candida albicans.
abstract: OBJECTIVE
  To explore the innate response of human corneal epithelial cells (HCECs) exposed to fungus by producing antimicrobial peptides LL-37 and β-defensins.
  
  
  METHODS
  Primary HCECs were treated with heat-killed Candida albicans (HKCA) at different doses (10(3)-10(6) cells/ml) for 2-48 h. The cells were subjected to total RNA extraction, reverse transcription and quantitative real-time PCR for mRNA expression. Cells treated for 48 h were used for immunofluorescent staining and ELISA.
  
  
  RESULTS
  Human LL-37 and β-defensins (hBDs) 1-4 were detected in normal HCECs. The mRNA expression of LL-37, hBD2, and hBD3 was dose-dependently induced by HKCA with their peak levels at 4 h. HKCA (10(6) cells/ml) stimulated the mRNA of LL-37, hBD2, and hBD3 4.33 ± 1.81, 3.75 ± 1.31, and 4.91 ± 1.09 fold, respectively, in HCECs. The stimulated production of LL-37, hBD2, and hBD3 by HKCA was confirmed at protein levels by immunofluorescent staining and ELISA. The protein production of LL-37, hBD2, and hBD3 significantly increased to 109.1 ± 18.2 pg/ml, 4.33 ± 1.67 ng/ml, and 296.9 ± 81.8 pg/ml, respectively, in culture medium of HCECs exposed to HKCA (10(6) cells/ml) compared to untreated HCECs.
  
  
  CONCLUSIONS
  HCECs produce antimicrobial peptides, LL-37, hBD2 and hBD3, in response to stimulation of HKCA, which suggests a novel innate immune mechanism of the ocular surface in defense against fungal invasion.
authors.affiliation: Tianjin Eye Hospital, Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China.
authors.forename: Xia
authors.initials: X
authors.lastname: Hua
authors.forename: Xiaoyong
authors.initials: X
authors.lastname: Yuan
authors.forename: Xin
authors.initials: X
authors.lastname: Tang
authors.forename: Zhijie
authors.initials: Z
authors.lastname: Li
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Pflugfelder
authors.forename: De-Quan
authors.initials: DQ
authors.lastname: Li
mesh_terms: D000328:Adult; D023181:Antimicrobial Cationic Peptides / Q000096:biosynthesis / Q000235:genetics*; D002176:Candida albicans / Q000502:physiology*; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D004847:Epithelial Cells / Q000378:metabolism / Q000382:microbiology; D019573:Epithelium, Corneal / Q000378:metabolism* / Q000382:microbiology; D019084:Fluorescent Antibody Technique, Indirect; D005786:Gene Expression Regulation / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D055815:Young Adult; D023083:beta-Defensins / Q000096:biosynthesis / Q000235:genetics*; D054804:Cathelicidins
chemical_list: D023181:Antimicrobial Cationic Peptides; D012333:RNA, Messenger; D023083:beta-Defensins; D054804:Cathelicidins