BMP4 and retinal degeneration: AMD pathology is characterized by RPE cell death, which precedes geographic atrophy and leads to eventual deterioration of the overlying photoreceptors.31 In addition, RPE cell death induced by various stressors such as hydrogen peroxide (tBHP), BMP4, and hypoxia has been demonstrated in in vitro AMD models,32, 33, 34 and in several retinal degeneration animal models.35, 36 Consistent with those findings, our results with Trypan blue and MTT cell viability assays demonstrated substantial increase in AMD cybrid cell death at 24h, 48h, and 72 h time points.