PURPOSE: Retinal pigment epithelium (RPE) cells may alter the phenotype of monocytes by soluble factors that may be influenced by stimulation of the RPE. Since RPE cells carry the toll-like receptor-3 (TLR3) that detects and reacts to viral infection through binding of dsRNA we investigated the effects of RPE cells with or without TLR3 stimulation on blood-derived monocytes with respect to regulation of pro-/anti-inflammatory cytokines, anti-angiogenic factors and migratory properties. METHODS: Primary RPE cells were prepared from porcine eyes; monocytes were prepared from porcine blood. TLR3 activation was induced by polyinosinic:polycytidylic acid (Poly I:C). RPE cells were stimulated with Poly I:C in different concentrations for 24 hours and a cell culture supernatant was applied to the monocytes. Expression of CD14 and Fas ligand (FasL) was determined via flow cytometry. The expression of IL-6, IL-1ß, TNFα, Cox2, iNOS and IL-10 was determined via quantitative RT-PCR. Migration was determined using Boyden chamber experiments. RESULTS: The supernatant of RPE cells, irrespective of TLR3 activation, induced FasL expression in the monocytes. Expression of iNOS and Cox2 was reduced by RPE cells and the reduction of Cox2 but not if iNOS was lost under TLR3 activation. No induction of IL-6, IL-1ß, IL-10 or TNFα by the RPE was seen. TLR3-activated RPE cells induced monocyte migration. CONCLUSION: RPE cells induce an upregulation of FasL and a downregulation of iNOS and Cox2 without upregulating inflammatory cytokines, possibly inducing an anti-angiogenic phenotype in the monocytes. This phenotype is still upheld after challenging RPE cells with dsRNA, mimicking a viral infection.
PURPOSE: Retinal pigment epithelium (RPE) cells may alter the phenotype of monocytes by soluble factors that may be influenced by stimulation of the RPE. Since RPE cells carry the toll-like receptor-3 (TLR3) that detects and reacts to viral infection through binding of dsRNA we investigated the effects of RPE cells with or without TLR3 stimulation on blood-derived monocytes with respect to regulation of pro-/anti-inflammatory cytokines, anti-angiogenic factors and migratory properties. METHODS: Primary RPE cells were prepared from porcine eyes; monocytes were prepared from porcine blood. TLR3 activation was induced by polyinosinic:polycytidylic acid (Poly I:C). RPE cells were stimulated with Poly I:C in different concentrations for 24 hours and a cell culture supernatant was applied to the monocytes. Expression of CD14 and Fas ligand (FasL) was determined via flow cytometry. The expression of IL-6, IL-1ß, TNFα, Cox2, iNOS and IL-10 was determined via quantitative RT-PCR. Migration was determined using Boyden chamber experiments. RESULTS: The supernatant of RPE cells, irrespective of TLR3 activation, induced FasL expression in the monocytes. Expression of iNOS and Cox2 was reduced by RPE cells and the reduction of Cox2 but not if iNOS was lost under TLR3 activation. No induction of IL-6, IL-1ß, IL-10 or TNFα by the RPE was seen. TLR3-activated RPE cells induced monocyte migration. CONCLUSION: RPE cells induce an upregulation of FasL and a downregulation of iNOS and Cox2 without upregulating inflammatory cytokines, possibly inducing an anti-angiogenic phenotype in the monocytes. This phenotype is still upheld after challenging RPE cells with dsRNA, mimicking a viral infection.
Authors: Dongli Yang; Susan G Elner; Xun Chen; Matthew G Field; Howard R Petty; Victor M Elner Journal: Invest Ophthalmol Vis Sci Date: 2011-07-29 Impact factor: 4.799
Authors: Jared E Knickelbein; Baoying Liu; Anush Arakelyan; Sonia Zicari; Susan Hannes; Ping Chen; Zhiyu Li; Jean-Charles Grivel; Benjamin Chaigne-Delalande; H Nida Sen; Leonid Margolis; Robert B Nussenblatt Journal: Invest Ophthalmol Vis Sci Date: 2016-08-01 Impact factor: 4.799