C5a receptor-mediated production of IL-8 by the human retinal pigment epithelial cell line, ARPE-19.
OBJECTIVE
C5a anaphylatoxin is a potent inflammatory mediator that acts on polymorphonuclear cells (PMN) and monocytes via C5a receptors (C5aR). It mediates chemotaxis of both cell types and stimulates cytokine release from the latter. To investigate whether C5a can act on retinal pigment epithelial (RPE) cells, we examined ARPE-19 cells for the presence of C5aR and the effect of C5a stimulation.


METHODS
C5aR expression was measured by flow cytometry using specific anti-C5aR antibody and by RT-PCR analyses. Cells were stimulated with 50 nM C5a and the induction of IL-8 mRNA expression was measured by semi-quantitative RT-PCR.


RESULTS
Surface levels of C5aR on ARPE-19 cells were found to be comparable to those on human PMN. Stimulation with C5a induced a dose- and time-dependent increase of IL-8 mRNA expression.


CONCLUSIONS
The findings of C5aR on ARPE-19 cells and induction of IL-8 mRNA upon C5a stimulation suggests that C5a may participate in the defense of choroidal and retinal tissue during inflammation.
Fukuoka
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Institute of Pathology, Case Western Reserve University, Cleveland, Ohio 44106, USA. mxm16@po.cwru.edu
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D015703:Antigens, CD / Q000378:metabolism*; D002460:Cell Line; D015936:Complement C5a / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D006801:Humans; D016209:Interleukin-8 / Q000096:biosynthesis / Q000235:genetics*; D010857:Pigment Epithelium of Eye / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis*; D044087:Receptor, Anaphylatoxin C5a; D011951:Receptors, Complement / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
D015703:Antigens, CD; D016209:Interleukin-8; D012333:RNA, Messenger; D044087:Receptor, Anaphylatoxin C5a; D011951:Receptors, Complement; D015936:Complement C5a