Purchase this article with an account.
M.V. Kumar, C.N. Nagineni, M.S. Chin, J.J. Hooks, B. Detrick; Double Stranded RNA (poly I:C) Up Regulates Toll-Like Receptor 3 and Induces Interferon ß (IFN-ß) in Human Retinal Pigment Epithelial Cells . Invest. Ophthalmol. Vis. Sci. 2003;44(13):738.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: The family of Toll-like receptors (TLRs) plays a key role in controlling innate immune responses. Recent studies indicate that TLR3 is a receptor for dsRNA produced by viruses and that dsRNA binding to TLR3 results in production of type 1 interferons (IFN). In this study we investigated expression of TLR3 in human retinal pigment epithelial cells (HRPE). Methods: HRPE cell cultures were stimulated with poly I:C at 100µg/ml, or LPS at 5 µg/ml for 24 hours. The human monocyte cell line (U937) was used as a control cell line. Total RNA prepared from control unstimulated and stimulated cells were used for analysis of the steady state levels of the TLR mRNA by RT-PCR. Production of type 1 IFNs were assayed by EIA and inhibition of virus plaque assay. Results: The most prominent enhancement of TLR gene expression in HRPE was seen with TLR3. In contrast, with the exception of TLR3, mRNA for all of the TLRs was detected in U937 cells. HRPE showed enhanced cytoplasmic staining for TLR3 in cells treated with poly I:C. Since poly I:C treatment up-regulated both TLR3 mRNA and protein expression, we next evaluated the effect of poly I:C treatment on type 1 IFN production. HRPE cells treated with poly I:C secreted 5 to 9 units of IFN-ß. In contrast, the other type 1 IFN, IFN-α, was not detected. Moreover, supernatant fluids from untreated HRPE cells or from LPS treated HRPE cells did not contain either type 1 IFN. Recombinant human IFN-ß was shown to be biologically active on HRPE cells. Using Vesicular Stomatitis Virus plaque inhibition assay, we found that 1 and 10 units of rIFN-ß inhibited virus replication in HRPE cells by 90% and 100%, respectively. Conclusions: The HRPE cell is one of a select number of cells that express TLR3. TLR3 triggered production of IFN-ß in HRPE may play a major role in retinal infectious diseases.
This PDF is available to Subscribers Only