Researchers from the National Institutes of Health (NIH) have discovered the source of dysfunction in the process whereby cells in the eye’s retina remove waste.
A report by scientists at NIH and Johns Hopkins University, Baltimore, Maryland, details alterations in a factor called AKT2. These changes affect lysosome function and result in drusen production, a hallmark sign of dry age-related macular degeneration (AMD). According to the researchers, the findings suggest drusen formation is a downstream effect of AKT2-related lysosome dysfunction and points to a new target for therapeutic intervention.
AMD RISK
In mice, the researchers manipulated AKT2 expression levels in RPE. When they overexpressed AKT2, lysosomes lost normal function and the mice developed dry AMD symptoms such as RPE degeneration. Researchers saw similar features in RPE cells from human donors with AMD or in RPE cells generated from patient stem cells. Cells from donors with a gene variant called CFH Y402H, which increases AMD risk, had relatively greater expression of AKT2, showed functionally defective lysosomes and formed drusen deposits.
This study’s findings form the basis for a possible future treatment for dry AMD, for which no therapy currently exists. AMD is one of the most common causes of vision loss in the United States. People with dry AMD develop drusen in an area of the light-sensing retina called the macula that people use for sharp, central vision.
The study builds upon previous work published by Ruchi Sharma, Ph.D., also of the NEI Section on Ocular Stem Cell and Translational Research Section, who developed the AMD patient stem cell-derived RPE model (Sharma et al., 2021).
Read more: Ghosh S, Sharma R, et al. The AKT2/SIRT5/TFEB pathway as a potential therapeutic target in non-neovascular AMD. Nat Commun. 2024 Jul 21;15(1):6150. doi: 10.1038/s41467-024-50500-z.
Read about earlier research on AMD in Women In Optometry.
