Ablating VHL in Rod Photoreceptors Modulates RPE Glycolysis and Improves Preclinical Model of Retinitis Pigmentosa

Neuroretinal degenerations including retinitis pigmentosa (RP) comprise a heterogeneous collection of pathogenic mutations that ultimately result in blindness. Despite recent advances in precision medicine, therapies for rarer mutations are hindered by burdensome developmental costs. To this end, Von Hippel-Lindau (VHL) is an attractive therapeutic target to treat RP. By ablating VHL in rod photoreceptors and elevating hypoxia-inducible factor (HIF) levels, we demonstrate a path to therapeutically enhancing glycolysis independent of the underlying genetic variant that slows degeneration of both rod and cone photoreceptors in a preclinical model of retinitis pigmentosa. This rod-specific intervention also resulted in reciprocal, decreased glycolytic activity within the retinal pigment epithelium (RPE) cells despite no direct genetic modifications to the RPE. Suppressing glycolysis in the RPE provided notable, non-cell-autonomous therapeutic benefits to the photoreceptors, indicative of metabolically sensitive crosstalk between different cellular compartments of the retina. Surprisingly, targeting HIF2A in RPE cells did not impact RPE glycolysis, potentially implicating HIF1A as a major regulator in mouse RPE and providing a rationale for future therapeutic efforts aimed at modulating RPE metabolism. Overall design: RNA seq profiling of bulk neuroretina following VHL or VHL and HIF1A ablation in rod photoreceptors at 3 weeks of age compared to controls

包含色素性视网膜炎（retinitis pigmentosa, RP）在内的神经视网膜退行性疾病，是一组由多种致病突变导致的异质性疾病，最终可致患者失明。尽管精准医学领域近年取得诸多进展，但针对罕见突变的治疗方案仍受限于高昂的研发成本。为此，希佩尔-林道综合征（Von Hippel-Lindau, VHL）成为治疗RP的极具潜力的治疗靶点。本研究通过在视杆感光细胞中敲除VHL并上调缺氧诱导因子（hypoxia-inducible factor, HIF）的表达水平，证实了一条可独立于患者潜在遗传变异的治疗路径：通过该路径可增强糖酵解，进而延缓色素性视网膜炎临床前模型中视杆与视锥感光细胞的退行性病变。该仅针对视杆细胞的干预手段，即便未对视网膜色素上皮（retinal pigment epithelium, RPE）细胞进行直接遗传改造，也可反向降低其糖酵解活性。抑制RPE细胞的糖酵解，可对感光细胞产生显著的非细胞自主型治疗获益，这表明视网膜不同细胞区间存在代谢敏感的互作调控。令人意外的是，在RPE细胞中靶向HIF2A并不会影响其糖酵解活性，这提示HIF1A可能是小鼠RPE细胞中的主要调控因子，也为未来靶向调控RPE代谢的治疗研究提供了理论依据。实验整体设计：选取3周龄小鼠，在其视杆感光细胞中分别敲除VHL，或同时敲除VHL与HIF1A，随后对整块神经视网膜进行转录组测序（RNA-seq）分析，并与对照组进行对比。