Chandler, L. C. | Search bioRxiv

bioRxiv2025

A Congenic C57BL/6 rd1 Mouse Model for Retinal Degeneration Research

Retinitis pigmentosa is an inherited retinal disease caused by thousands of mutations in approximately 100 different genes. The most widely used mouse model for retinitis pigmentosa has the retinal degeneration 1 (rd1) mutation in the Pde6b gene, which elicits rapid retinal degeneration and vision loss. A major limitation of these models is that these rd1 strains are not congenic, which prevents the use of appropriate controls. Furthermore, many strains have mutations in other genes which introduces genetic variability and may confound results. To address this issue, we backcrossed the rd1 allele from FVB mice onto a C57BL/6J genetic background over many generations, producing a C57BL/6J.Pde6brd1 strain that was confirmed to be congenic to C57BL/6J mice. We show that this strain recapitulates the electroretinogram and optomotor results expected for mouse strains containing the rd1 mutation. Examination of retinal structure in cross sections of eyes isolated from C57BL/6J.Pde6brd1 mice show a degree of thinning of the outer nuclear layer expected for a rd1 mutation, resulting in nearly complete loss of the outer nuclear layer by postnatal day 35. We anticipate that this C57BL/6J.Pde6brd1 strain could become an asset for the field of retinitis pigmentosa research.

genetics↗

bioRxiv2024

RPE-specific MCT2 expression promotes cone survival in models of retinitis pigmentosa

Retinitis pigmentosa (RP) is the most common cause of inherited retinal degeneration worldwide. It is characterized by the sequential death of rod and cone photoreceptors, the cells responsible for night and daylight vision, respectively. Although mutations in RP are mostly rod-specific, there is a secondary degeneration of cones. One possible mechanism behind cone death is metabolic dysregulation. Photoreceptors are highly metabolically active, consuming large quantities of glucose and producing substantial amounts of lactate. The retinal pigment epithelium (RPE) mediates the transport of glucose from the blood to photoreceptors and, in turn, removes lactate, which it can use as its own source of fuel. The model for metabolic dysregulation in RP suggests that, following the death of rods, lactate levels are substantially diminished causing the RPE to withhold glucose, resulting in nutrient deprivation for cones. Here, we present adeno-associated viral vector-mediated delivery of monocarboxylate transporter 2 (MCT2) into RPE cells with the aim of promoting lactate uptake from the blood and encouraging the passage of glucose to cones. We demonstrate prolonged survival and function of cones in rat and mouse RP models, revealing a possible gene agnostic therapy for preserving vision in RP. We also present the use of fluorescence lifetime imaging-based biosensors for lactate and glucose within the eye. Using this technology, we show changes to lactate and glucose levels within MCT2-expressing RPE, suggesting cone survival is impacted by RPE metabolism.

neuroscience↗