Breakthrough Compounds Illuminate Hope for Retinitis Pigmentosa Treatment

Two novel compounds could potentially address retinitis pigmentosa, a category of hereditary eye disorders that result in blindness. These compounds, highlighted in a study published on January 14^th in the open-access journal PLOS Biology by Beata Jastrzebska from Case Western Reserve University, US, and collaborators, were discovered through a virtual screening method.

In individuals with retinitis pigmentosa, the retinal protein rhodopsin frequently misfolds owing to genetic alterations, which leads to the demise of retinal cells and results in progressive visual impairment. There is a pressing need for small molecules that can rectify rhodopsin folding to treat the approximately 100,000 individuals in the United States afflicted with the condition. Existing experimental therapies involve retinoid compounds, such as synthetic vitamin A derivatives, which are susceptible to light and can be harmful, presenting several limitations.

In this recent research, scientists employed virtual screening to look for new drug-like molecules that bind to and stabilize the structure of rhodopsin to enhance its folding and transport within the cell. Two non-retinoid compounds were identified that fulfilled these requirements and had the capability to penetrate the blood-brain and blood-retina barriers. The research team conducted laboratory tests on the compounds and demonstrated that they improved the cell surface expression of rhodopsin in 36 of 123 genetic variants of retinitis pigmentosa, including the most prevalent type. Furthermore, they provided protection against retinal degeneration in mice exhibiting retinitis pigmentosa.

“Crucially, treatment with either compound enhanced the overall health and functionality of the retina in these mice by extending the lifespan of their photoreceptors,” the authors remark. Nevertheless, they acknowledge that further investigations of these compounds or related substances are required before progressing to human trials.

The authors add, “Hereditary mutations in the rhodopsin gene lead to retinitis pigmentosa (RP), a progressive and currently incurable blinding disorder. This study identifies small molecule pharmacochaperones that mitigate the detrimental effects of various rhodopsin mutants in vitro and decelerate photoreceptor cell death in a mouse model of RP, presenting a promising new therapeutic strategy to avert vision loss.”