Abstract
Purpose :
It is well known that retinal pigment epithelial cells are able to express and secrete cytokines and present antigens, however the role of melanin in RPE cell immune response has not been established. This study evaluates immune response in photo-stressed pigmented and unpigmented ARPE-19 cells by monitoring interleukin-6 (IL-6) expression and secretion.
Methods :
ARPE-19 cells were pigmented with bovine melanin and subjected to UVC irradiation or dark treatment. Unpigmented ARPE-19 cells were used as a control. IL-6 secretion was measured using an enzyme-linked immunosorbent assay (ELISA) and gene expression was detected using PCR. Relative IL-6 secretion was evaluated in comparison to dark-treated unpigmented ARPE-19 cells. Statistical analysis was performed using a two-tailed Student’s t-test.
Results :
IL-6 secretion was significantly increased in UVC stressed unpigmented (p = 0.004) and pigmented (p < 0.0001) ARPE-19 cells. Elevated IL-6 secretion was observed in pigmented cells under dark (111±9%) and photo-stress (164±8%) conditions compared to unpigmented dark control cells. Additionally, photo-stressed pigmented cells showed a 113±6% increase compared to irradiated unpigmented cells.
Conclusions :
The presence of melanin in ARPE-19 cells results in an increase in IL-6 secretion under dark and photo-stress conditions compared to unpigmented cells. This finding suggests that RPE cell pigmentation may be related to the immune response of these cells. Monitoring expression and secretion of related pro-inflammatory cytokines and signaling factors is needed to further investigate melanin-dependent immune response.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.