Abstract
Age-related macular degeneration (AMD) is a leading cause of blindness worldwide, affecting more than 200 million people1. Unfortunately, therapeutic options for dry-AMD, the most common form accounting for 80- 90% of cases, remain limited. A major challenge in developing effective treatments is the absence of reliable in vitro AMD models, which has slowed drug discovery efforts. The cell type primarily affected in AMD is the retinal pigment epithelium (RPE). While primary and immortalized RPE lines have provided valuable insights into RPE functions under normal and pathological conditions, they exhibit limitations for drug discovery, including low amplification potential in primary RPE cells and a lack of maturation in immortalized RPE lines.
The advent of induced pluripotent stem cell (iPSC) technology has enabled the generation of unlimited quantities of mature, functional RPE cells for large-scale research. Moreover, iPSCs allow the derivation of cell lines from multiple AMD patients, facilitating the study of how genetic background influences disease progression and treatment efficacy.
To establish a highly relevant in vitro AMD model, we have developed a protocol for the large-scale differentiation of multiple iPSC lines into RPE cells. These cells are then treated with chronic low doses of A2E and exposed to blue light, simulating lipofuscin accumulation, an aging mechanism implicated in AMD. Our results demonstrated that this combination of stressors induces AMD hallmarks in iPSC-derived RPE cells, including increased oxidative stress, complement pathway activation, increased pro-inflammatory cytokine secretion, and RPE atrophy.
In collaboration with the Hospital Center of Créteil, we collected 26 cell lines from AMD patients, some of whom carry genetic risk alleles such as CFH and HTRA1, which are associated with increased susceptibility to AMD. We are currently differentiating these cell lines into RPE cells and assessing their behavior in our AMD model. Results from the first set of lines suggest that cells carrying a combination of CFH, HTRA1, and ARMS2 risk alleles are more sensitive to combined A2E and blue light stress.
