Abstract
Purpose. Retinal pigment epithelial (RPE) cells are easily activated by interleukin-1β (IL-1β) to produce various inflammatory cytokines. In the present study we investigated whether RPE cells are able to produce IL-1 receptor antagonist (IL-1RA), a natural inhibitor of IL-1 mediated responses. Methods. Human RPE cells were isolated from seven donors. Experiments were performed with cells of the fourth till twelfth passage. RPE cells were grown near confluency and incubated without or with IL-1β (100 U/ml) or phorbol myristate acetate (PMA; 20 ng/ml) and RNA was isolated at different time points. Semi-quantitative RT-PCR analysis was used to determine mRNA expression of the IL-1RA. By means of specific primer pairs, the intracellular (ic) and the secreted (s) form of IL-1RA were distinguished. Results. All RPE cells tested constitutively expressed icIL-1RA mRNA, but not sIL-1RA mRNA. Expression of icIL-1RA was upregulated by either PMA or IL-1β (PMA > IL-1β) at t = 4 and 24 hours. In addition to icIL-1RA expression, a number of RPE cultures (2 out of 7) also produced sIL-1RA mRNA after stimulation. Conclusions. These results indicate that stimulated RPE cells can produce IL-1RA suggesting that RPE cells possess an inherent control mechanism for IL-1 mediated responses.
| Original language | English |
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| Pages (from-to) | S544 |
| Journal | Investigative Ophthalmology and Visual Science |
| Volume | 37 |
| Issue number | 3 |
| Publication status | Published - 15 Feb 1996 |