Abstract
Purpose :
Autosomal dominant Retinitis Pigmentosa (adRP), an inherited degenerative disease causing blindness in later life, is frequently caused by dominant mutations in the rhodopsin gene (RHO). We previously characterized cell death pathways activated in a mouse model expressing the P23H RHO mutation and found to be linked to increased intracellular calcium, activation of calpains and Apoptosis inducing factor (Aif) as well as activation of ER-stress and caspase 7. Given that therapies for adRP are still not available, neuroprotection was evaluated as a novel therapy based on PEDF that was reported to be downregulated during retinal degeneration.
Methods :
In vivo treatment of RhoP23H/+ mice were performed by intraocular injections of AAV expressing either Pigment Epithelium-derived Factor (PEDF) or a small peptide from the neuroprotection domain of PEDF (17mer[H105A]). Neuroprotection was assessed by histological analysis as well as molecular analysis by western blotting and immunofluorescence of cell death pathways.
Results :
We developed different viral systems to restore PEDF levels in the degenerating retina. We tested neuroprotection by intravitreal or subretinal injections of AAV expressing PEDF or 17mer[H105A]. We found that PEDF protected more than 40% of photoreceptors from cell death in the RhoP23H/+ mutant retina and the 17mer[H105A] was even more efficient. Interestingly, PEDF was found to reduce activation of calpains and of the apoptosis inducing factor (Aif) involved in photoreceptor cell demise.
Conclusions :
PEDF demonstrated to act at early stages of photoreceptor cell death. Long-term exposure to PEDF will be discussed.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.