Document Detail


Role of defensins in corneal epithelial barrier function against Pseudomonas aeruginosa traversal.
MedLine Citation:
PMID:  21115716     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Studies have shown that epithelium-expressed antimicrobial peptides (AMPs), e.g., β-defensins, play a role in clearing bacteria from mouse corneas already infected with Pseudomonas aeruginosa. Less is known about the role of AMPs in allowing the cornea to resist infection when healthy. We previously reported that contact lens exposure, a major cause of P. aeruginosa keratitis, can inhibit the upregulation of human β-defensin 2 (hBD-2) by corneal epithelial cells in response to P. aeruginosa antigens in vitro. Here, we studied the role of AMPs in maintaining the corneal epithelial barrier to P. aeruginosa penetration using both in vitro (human) and in vivo (mouse) experiments. Results showed that preexposing human corneal epithelial multilayers to bacterial antigens in a culture supernatant (known to upregulate AMP expression) reduced epithelial susceptibility to P. aeruginosa traversal up to 6-fold (P < 0.001). Accordingly, small interfering RNA (siRNA) knockdown of any one of four AMPs expressed by human epithelia promoted P. aeruginosa traversal by more than 3-fold (P < 0.001). The combination knockdown of AMPs further enhanced susceptibility to bacterial traversal by ∼8-fold (P < 0.001). In vivo experiments showed that the loss of murine β-defensin 3 (mBD-3), a murine ortholog of hBD-2, enhanced corneal susceptibility to P. aeruginosa. The uninjured ocular surface of mBD-3(-/-) mice showed a reduced capacity to clear P. aeruginosa, and their corneal epithelia were more susceptible to bacterial colonization, even when inoculated ex vivo to exclude tear fluid effects. Together, these in vitro and in vivo data show functional roles for AMPs in normal corneal epithelial cell barrier function against P. aeruginosa.
Authors:
Danielle K Augustin; Susan R Heimer; Connie Tam; Wing Y Li; Jeff M Le Due; David J Evans; Suzanne M J Fleiszig
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2010-11-29
Journal Detail:
Title:  Infection and immunity     Volume:  79     ISSN:  1098-5522     ISO Abbreviation:  Infect. Immun.     Publication Date:  2011 Feb 
Date Detail:
Created Date:  2011-01-24     Completed Date:  2011-03-15     Revised Date:  2011-08-03    
Medline Journal Info:
Nlm Unique ID:  0246127     Medline TA:  Infect Immun     Country:  United States    
Other Details:
Languages:  eng     Pagination:  595-605     Citation Subset:  IM    
Affiliation:
Graduate Group in Microbiology, Department of Plant and Microbial Biology, University of California, Berkeley, California, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Cell Line
Defensins / metabolism*
Epithelium, Corneal / metabolism*,  microbiology*
Gene Expression Regulation / physiology
Humans
Mice
Mice, Inbred C57BL
Mice, Knockout
Pseudomonas aeruginosa / physiology*
beta-Defensins / genetics,  metabolism
Grant Support
ID/Acronym/Agency:
EY011221/EY/NEI NIH HHS; EY019456/EY/NEI NIH HHS; R01 EY011221-14/EY/NEI NIH HHS
Chemical
Reg. No./Substance:
0/Defensins; 0/beta-Defensins; 0/beta-defensin 3, mouse
Comments/Corrections

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