Expression of Human Beta-Defensins in Intraocular Tissues

Defensins are naturally occurring antimicrobial peptides. Recently the authors published evidence of defensin production by the human ocular surface. A study was undertaken to look for intraocular defensins that may account for unexplained antimicrobial activity of intraocular fluids. Reverse transc...

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Bibliographic Details
Published in:	Investigative ophthalmology & visual science Vol. 41; no. 10; pp. 3026 - 3031
Main Authors:	Haynes, Richard John, McElveen, Jane Elizabeth, Dua, Harminder Singh, Tighe, Patrick Jason, Liversidge, Janet
Format:	Journal Article
Language:	English
Published:	Rockville, MD ARVO 01-09-2000 Association for Research in Vision and Ophtalmology
Subjects:	Aqueous Humor - metabolism beta-Defensins Biological and medical sciences Cells, Cultured Ciliary Body - drug effects Ciliary Body - metabolism Cytokines - pharmacology Defensins DNA Primers - chemistry Eye and associated structures. Visual pathways and centers. Vision Fundamental and applied biological sciences. Psychology Gene Expression Humans Immunoblotting Pigment Epithelium of Eye - drug effects Pigment Epithelium of Eye - metabolism Protein Biosynthesis Proteins - genetics Reverse Transcriptase Polymerase Chain Reaction RNA - isolation & purification RNA, Messenger - biosynthesis Vertebrates: nervous system and sense organs Vitreous Body - metabolism Human Infection Eye Cell culture Eye disease Cytokine Postmortem Vitreous body Defense mechanism Aqueous humor Defensin
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Summary:	Defensins are naturally occurring antimicrobial peptides. Recently the authors published evidence of defensin production by the human ocular surface. A study was undertaken to look for intraocular defensins that may account for unexplained antimicrobial activity of intraocular fluids. Reverse transcription-polymerase chain reaction (RT-PCR) was performed on human postmortem ciliary body samples for beta defensins-1 (HBD-1) and beta defensin-2 (HBD-2), and alpha defensins 5 and 6. Induction of defensins by cytokines was analyzed in cultured human ciliary body epithelial (CBE) and retinal pigment epithelial (RPE) cells. Polyclonal antibodies were used to immunoblot aqueous and vitreous to detect HBD-1 and HBD-2 and to estimate their concentration. RT-PCR revealed constitutive HBD-1 message in ciliary body. HBD-2 and alpha defensin 5 and 6 messages were absent. HBD-2 message was induced by cytokine stimulation of both CBE and RPE cells. Immunoblots of vitreous and aqueous stained positively for HBD-1 but not HBD-2. The estimated aqueous concentration of HBD-1 was less than 16 ng/ml. This study demonstrates that HBD-1 is constitutively present in the aqueous and vitreous, probably at sub-bacteriocidal concentrations. HBD-2 was absent from aqueous, but cytokine stimulation studies suggest that it may be generated in response to inflammatory cytokines during infections. HBD-2 has a wider antibacterial spectrum, is 10-fold more potent, and may play a more significant role in antimicrobial defense than HBD-1. The use of defensins therapeutically may be indicated; however, caution is required because defensins also promote cell proliferation and fibrin formation, which are 2 key elements in ocular scarring processes such as proliferative vitreoretinopathy.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0146-0404 1552-5783