Dysmorphic Photoreceptors in a P23H Mutant Rhodopsin Model of Retinitis Pigmentosa Are Metabolically Active and Capable of Regenerating to Reverse Retinal Degeneration

This paper (and the cover article) is the result of a collaborative effort between Damian C. Lee, Felix R. Vazquez-Chona, W. Drew Ferrell, Beatrice M. Tam, Bryan W. JonesRobert E. Marc, and Orson L. Moritz.

The retinal degenerative disease retinitis pigmentosa (RP) is characterized by the progressive degeneration of rod photoreceptors of the retina.  The proline-to-histidine substitution at position 23 (P23H) of rhodopsin mutation is responsible for the majority of cases of autosomal dominant RP (adRP) in North America, and there is some evidence that light exacerbates P23H-mediated retinal degeneration.  In this study performed on P23H expressing transgenic Xenopus laevis, degenerated rod photoreceptors remain metabolically active despite having completely lost their outer segments.  This degeneration can be partially reversed, with regeneration of outer segments, by keeping the animals in complete darkness.  The results from this study suggest that P23H-rhodopsin RP patients may have a pool of rod photoreceptor cells that are dystrophic but still viable, which could be targeted with therapeutic interventions that slow, prevent or even reverse degeneration.

Image Credit:  Bryan William Jones and William Drew Ferrell and Carl B. Watt.