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PEDF peptides promote photoreceptor survival in rd10 retina models.

Research paper by Alberto A Hernández-Pinto, Federica F Polato, Preeti P Subramanian, Andrés de la A Rocha-Muñoz, Susan S Vitale, Enrique J EJ de la Rosa, S Patricia SP Becerra

Indexed on: 18 Jul '19Published on: 14 Apr '19Published in: Experimental Eye Research



Abstract

The purpose of the study is to evaluate the protective properties of PEDF peptide fragments on rd10 mouse models of retinal degeneration ex vivo. Human recombinant PEDF and synthetic peptides were used. Rd10 retinal explants as well as wild-type retinal explants treated with zaprinast to mimic the rd10 photoreceptor cell death were employed. PEDF protein was intravitreally administered into rd10 mice. Outer nuclear layer thickness measurements in retinal sections, TUNEL labeling in retinal explants, western blots and immunofluorescence with retinal samples were performed. PEDF protein levels in the RPE of rd10 mice decreased with age (P15 - P25). Levels of PEDF receptor PEDF-R declined in the photoreceptor inner segments from rd10 relative to wild-type mice at P25. PEDF administration increased the outer nuclear layer thickness of rd10 retinas in vivo and decreased the number of TUNEL nuclei of photoreceptors in rd10 retinal explant cultures, both relative to untreated controls. Peptides containing the PEDF neurotrophic region decreased the number of TUNEL photoreceptors in both rd10 and zaprinast-induced cell death ex vivo models, while peptides without the neurotrophic region and/or lacking affinity for PEDF-R were ineffective in protecting photoreceptors. Thus, retinal explants are a valuable system to evaluate PEDF activity. Short peptides with the photoreceptor-protective property of PEDF may prove useful for the development of therapeutic agents for photoreceptor protection in retinal degenerations. Retinitis Pigmentosa (RP) is a collection of different genetic diseases that lead to progressive photoreceptor degeneration and ultimately vision loss. More than 60 genes are implicated in molecular pathways towards photoreceptor cell death (Wang et al., 2005). Currently, there are no treatments available and, due to its vast diverse genetic background, a putative gene-based therapy seems challenging. Consequently, mutation-independent strategies to protect photoreceptors against continued damage and progressive vision loss are appealing (Guadagni et al., 2015). One of them is the use of survival, neurotrophic and neuroprotective factors that target common signaling pathways of cell death in the different types of RP. Copyright © 2019. Published by Elsevier Ltd.