Abstract
Purpose :
Abnormal pigmentation of the retinal pigment epithelium (RPE) is a precursor to neovascular age-related macular degeneration (nAMD). We evaluated the effects of hydroquinone (HQ), the most potent reductant in cigarette smoke, on the melanin production in induced pluripotent stem cell (iPS) - derived RPE cells.
Methods :
iPS-RPE cells were cultured with 2 µM HQ for 1day or 1 week. After the HQ exposure, melanin production from the iPS-RPE cells were measured by Enzyme-linked immunosorbent immunoassay (ELISA). Changes in the expression of melanin production-related genes (DCT, TYR, TYRP1, OCA2, MC1R) were evaluated by Real-time reverse transcription polymerase chain reaction (RT-PCR). A suspension of iPS-RPE cells with HQ for 1day was prepared, and the light absorbance thorough the RPE suspension was measured. The blue light exposure was performed on the iPS-RPE with HQ for 1 week, and then vascular endothelial growth factor (VEGF) in the medium was measured by ELISA.
Results :
Real-time RT-PCR revealed that the expression of DCT, TYRP1, and OCA2 decreased due to the addition of HQ for 1 day (p < 0.05, 0.01, 0.01 respectively) while the expression of TYR did not change. ELISA results showed that the concentration of melanin significantly decreased due to the addition of HQ for 1 day (p < 0.05).
The light absorbance decreased specifically under the blue light exposure. Additionally, melanin levels significantly increased under HQ for 1 week (p < 0.05). The expression of MC1R mRNA was increased after exposure to HQ for the 1 week (p < 0.05) although the expressions of the other melanin production-related genes were decreased. After blue light exposure on the RPE with HQ for 1 week, VEGF level in the medium of the HQ group was significantly higher than that of the control group (p < 0.05).
Conclusions :
HQ-induced changes in melanin production may be responsible for the uneven pigmentation of the RPE, and these changes may cause nAMD.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.