A novel multiplex RNAi therapy simultaneously targets Hif1a and Hif2a to defy retinal degeneration in two models of AMD.

Age-related tissue changes lead to reduced oxygen delivery to photoreceptors and the retinal pigment epithelium (RPE), and contribute to the pathology of age-related macular degeneration (AMD). The implication of hypoxia-inducible factors (HIFs) in this process makes them good candidates as therapeutic targets for AMD. We developed a multiplex dual-acting therapy utilizing the shRNAmir system, delivered by a single AAV, that reduces mRNA levels of Hif1a in photoreceptors and Hif2a in the RPE. This RNA interference-based strategy demonstrated a strong therapeutic effect, potently preserving photoreceptors and the RPE in two models of pseudo- and true hypoxia up to 61 weeks post-injection. The efficacy of our dual-acting virus proved superior to single-acting viruses targeting only Hif1a in photoreceptors or Hif2a in the RPE. By targeting a common, conserved disease pathway, this gene-agnostic RNAi therapy shows significant potential to protect tissues from chronic hypoxic insults in complex diseases such as AMD.