TFEB-mediated reduction of autofluorescent granule load in retinal pigment epithelium

Abstract

Purpose : We are exploring pathways for autofluorescent granule (AFG) resolution by retinal pigment epithelium (RPE) cells to identify new therapeutic targets.

Methods : We are using an experimental model of RPE monolayers in culture where there is accumulation of AFGs similar to lipofuscin in vivo, after a single pulse of photoreceptor outer segments (POS). We previously observed that lysosomal dysfunction results in incomplete POS degradation and AFG accumulation. Here we are exploring gene therapy using adeno-associated viruses (AAV) and/or pharmacological approaches to target pathways that promote lysosomal function and biogenesis leading to AFGs reduced formation or its resolution, accessed by a variety of light and electron microscopical techniques, flow cytometry and western blot.

Results : We show that AAV-mediated over-expression of transcription factor EB (TFEB) reduces the load of AFG accumulation in RPE monolayers. Use of pharmacological inhibitors of mTOR leading to activation of TFEB, such as rapamycin, as well as other mTORC1 inhibitors, also led to a decrease in POS-dependent AFG accumulation in RPE.

Conclusions : These results suggest that viral or pharmacological approaches acting on the mTOR/TFEB axis may be beneficial in early/intermediate cases of AMD to delay progression of the disease.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.