Role of Retinal Epithelium in Retinal Disorders

Nagineni, C N.

Abstract

The retinal pigment epithelium (RPE) plays a critical role in the regulation of retinal and choroidal function in normal and disease states. Due to limited availability of human tissues, an in vitro cell culture system is desired. Therefore, we have developed and characterized the primary cell lines of human RPE (HRPE) from donor eyes obtained from eye banks. Using human RPE cell cultures as a model, we conducted investigations to examine the various roles of RPE in the pathophysiology of retinal disorders. Toxoplasma gondii (T. gondii), a protozoan parasite that causes uveitis, Was found to infect and replicate within HRPE cells. Interferons (IFN)-alpha, -beta, -gamma, and tumor necrosis factor-alpha (TNF-alpha) inhibit T. gondii replication in the cells in a dose-dependent manner. IFN-gamma is the most potent and can completely block T. gondii replication. The role of IFN-gamma is confirmed by using monoclonal antibodies (mab) raised against IFN-gamma, which reversed its effects. Antitoxoplasmosis activity of IFNs is by nitric oxide (NO)-independent mechanisms because they do not induce NO production in these cells. HRPE may be a useful model to study the effects of cytokines and drugs on T. gondii growth in retina and responses of HRPE to T. gondii infection. HRPE produce large amounts of NO in the presence of IFN-gamma, interleukin-1 (IL-1), and TNF-alpha. Reverse transcriptase-polymerase chain reaction (RT-PCR ) and Northern blot analysis indicated the expression of an inducible form of NO synthase (iNOS) upon treatment with cytokines. Transforming growth factor-beta (TGF-beta) inhibited cytokine-induced NO production and iNOS mRNA by 60 percent and 75 percent, respectively. Induction of NO by inflammatory cytokines and its regulation by TGF-beta in HRPE suggests a prominent role for RPE in inflammatory and infectious diseases of the retina and choroid. Mechanisms of transport of glutathione (GSH), a peptide involved in the cellular defense against oxidative injury, are studied in HRPE cells. Sodium-independent but temperature-dependent uptake and efflux suggest a carrier-mediated transport of GSH. Presence of low-affinity transporter of GSH was confirmed by Northern blot analysis of HRPE mRNA.

Funding Agency

• Agency: National Institute of Health (NIH)
• Institute: National Eye Institute (NEI)
• Type: Intramural Research (Z01)
• Project #: 1Z01EY000277-04
• Application #: 5202340
• Support Year: 4
• Fiscal Year: 1995

Institution

• Name: U.S. National Eye Institute
• Country: United States

Publications

Nagineni, Chandrasekharam N; William, Abitha; Cherukuri, Aswini et al. (2016) Inflammatory cytokines regulate secretion of VEGF and chemokines by human conjunctival fibroblasts: Role in dysfunctional tear syndrome. Cytokine 78:16-9

Nagineni, Chandrasekharam N; Cherukuri, Karthik S; Kutty, Veena et al. (2007) Interferon-gamma differentially regulates TGF-beta1 and TGF-beta2 expression in human retinal pigment epithelial cells through JAK-STAT pathway. J Cell Physiol 210:192-200

Hayashi, Kozaburo; Hooper, Laura C; Chin, Marian S et al. (2006) Herpes simplex virus 1 (HSV-1) DNA and immune complex (HSV-1-human IgG) elicit vigorous interleukin 6 release from infected corneal cells via Toll-like receptors. J Gen Virol 87:2161-9

Hooks, John J; Chin, Marian S; Srinivasan, Kumar et al. (2006) Human cytomegalovirus induced cyclooxygenase-2 in human retinal pigment epithelial cells augments viral replication through a prostaglandin pathway. Microbes Infect 8:2236-44

Djalilian, Ali R; Nagineni, Chandrasekharam N; Mahesh, Sankanaranayana P et al. (2006) Inhibition of inflammatory cytokine production in human corneal cells by dexamethasone, but not cyclosporin. Cornea 25:709-14

Nagineni, Chandrasekharam N; Kutty, Veena; Detrick, Barbara et al. (2005) Expression of PDGF and their receptors in human retinal pigment epithelial cells and fibroblasts: regulation by TGF-beta. J Cell Physiol 203:35-43

Chen, Kevin G; Szakacs, Gergely; Annereau, Jean-Philippe et al. (2005) Principal expression of two mRNA isoforms (ABCB 5alpha and ABCB 5beta ) of the ATP-binding cassette transporter gene ABCB 5 in melanoma cells and melanocytes. Pigment Cell Res 18:102-12

Kim, Ben J; Li, Zhuqing; Fariss, Robert N et al. (2004) Constitutive and cytokine-induced GITR ligand expression on human retinal pigment epithelium and photoreceptors. Invest Ophthalmol Vis Sci 45:3170-6

Kumar, Matam Vijay; Nagineni, Chandrasekharam N; Chin, Marian S et al. (2004) Innate immunity in the retina: Toll-like receptor (TLR) signaling in human retinal pigment epithelial cells. J Neuroimmunol 153:7-15

Nagineni, Chandrasekharam N; Samuel, William; Nagineni, Sahrudaya et al. (2003) Transforming growth factor-beta induces expression of vascular endothelial growth factor in human retinal pigment epithelial cells: involvement of mitogen-activated protein kinases. J Cell Physiol 197:453-62