In vitro modeling of the complex retinal condition age-related macular degeneration

Aim: To model a complex retinal disease such as age-related macular degeneration (AMD) in vitro, we aimed to combine genetic and environmental risk factors in a retinal pigment epithelium (RPE) cell culture model generated via induced pluripotent stem cells (iPSCs) from subjects with an extremely high and an extremely low genetic disease risk. As an external stimulus, we chose defined oxidative stress conditions. Methods: Patients were genotyped for known AMD-associated genetic variants and their individual genetic risk score (GRS) was calculated defining individual iPSC-RPE cell lines which reflect the extreme ends of the genetic risk for AMD. Sodium iodate (NaIO3, SI) was used to induce oxidative stress and cellular responses were followed by analyzing nuclear factor erythroid 2-related factor 2 (NRF2) pathway activation by mRNA and protein expression. Results: We present a collection of eight iPSC-RPE cell lines, with four each harboring an extreme low or an extreme high GRS for AMD. RPE identity was verified structurally and functionally. We found that 24 and 72 h of SI treatment induced a significant upregulation of NRF2 response genes HMOX1 and NQO1, without showing cytotoxic effects or negatively influencing RPE cell integrity. High- vs. low-risk cell lines revealed similar first line defenses in oxidative stress response mediated through the NRF2 pathway. Conclusion: Delineating the NRF2-mediated oxidative stress response was sought in iPSC-RPE cell lines with maximally divergent genetic AMD risk profiles. Under the specific stress conditions chosen, our data indicate that genetic predisposition to AMD may not exert a major influence on the NRF2 signaling pathway.