Monocyte-induced cytokine expression in cultured human retinal pigment epithelial cells

• Published in: Experimental eye research 1995-05, Vol.60 (5), p.533-543
• Main Authors: Jaffe, Glenn J., Roberts, Wendy L., Wong, Henry L., Yurochko, Andrew D., Cianciolo, George J.
• Format: Article
• Language: English
• Subjects: Antibodies - pharmacology; Biological and medical sciences; Cell Membrane - pathology; Cells, Cultured; cytokine; Cytokines - metabolism; Eye and associated structures. Visual pathways and centers. Vision; Fundamental and applied biological sciences. Psychology; Humans; Interleukin-1 - genetics; Interleukin-1 - immunology; Interleukin-1 - metabolism; messenger RNA; monocyte; Monocytes - metabolism; Pigment Epithelium of Eye - metabolism; Pigment Epithelium of Eye - pathology; Polymerase Chain Reaction; proliferative vitreoretinopathy; retinal pigment epithelium; RNA, Messenger - analysis; Tumor Necrosis Factor-alpha - genetics; Tumor Necrosis Factor-alpha - immunology; Tumor Necrosis Factor-alpha - metabolism; uveitis; Uveitis - metabolism; Vertebrates: nervous system and sense organs; Vitreoretinopathy, Proliferative - pathology
• ISSN: 0014-4835; 1096-0007
• DOI: 10.1016/S0014-4835(05)80068-5

Monocytes and retinal pigment epithelial cells are intimately associated in membranes of eyes with proliferative vitreoretinopathy and in certain types of uveitis. The goal of this study was to determine whether monocytes modulate cytokine expression in retinal pigment epithelial cells, and if so, to identify the monocyte products responsible for this effect. Cultured human retinal pigment epithelial cells were exposed to varying concentrations of monocyte-conditioned medium from unstimulated human monocytes for 1–48 hr, or from monocytes prestimulated with lipopolysaccharide. mRNA expression of interleukin-1 β, interleukin-6, interleukin-8, melanoma growth stimulating activity/gro α and γ, macrophage colony stimulating factor, transforming growth factor- β2, basic fibroblast growth factor and activin βA chain was determined by reverse transcription polymerase chain reaction. Protein secretion of selected cytokines, interleukin-1 β, interleukin-6, interleukin-8, macrophage colony stimulating factor and transforming growth factor- β2 was measured in RPE-conditioned medium by ELISA. Retinal pigment epithelial cells constitutively expressed mRNA for interleukin-6, macrophage colony stimulating factor, transforming growth factor- β2, basic fibroblast growth factor and activin βA chain. Interleukin-1 β, melanoma growth stimulating activity/gro α and γ and interleukin-8 were not expressed under basal conditions. Stimulated monocyte-conditioned medium markedly induced mRNA of all cytokines except basic fibroblast growth factor and transforming growth factor- β2 in a dose- and time-dependent manner. Unstimulated monocyte-conditioned medium was a less potent inducing agent, but still enhanced mRNA expression of interleukin-6, interleukin-8 and melanoma growth stimulating activity/gro α. Stimulated monocyte-conditioned medium also induced a time-dependent increase in interleukin-6, Interleukin-8, macrophage colony stimulation factor and transforming growth factor- β2, but not interleukin-1 β protein secretion ( p < 0.05 for all time points). Neutralizing antibodies to interleukin-1 β, or tumour necrosis factor α, but not interleukin-1 α, significantly reduced cytokine mRNA expression induced by stimulated monocyte-conditioned medium. the combination of all three neutralizing antibodies almost entirely eliminated monocyte-induced mRNA expression and protein production of all cytokines studied. Activated monocytes secrete a heterogeneous mixture of products that toget