Dataset Information

Intra-vitreal ?B crystallin fused to elastin-like polypeptide provides neuroprotection in a mouse model of age-related macular degeneration.

ABSTRACT: Age-related macular degeneration (AMD) is the leading cause of severe and irreversible central vision loss, and the primary site of AMD pathology is the retinal pigment epithelium (RPE). Geographic atrophy (GA) is an advanced form of AMD characterized by extensive RPE cell loss, subsequent degeneration of photoreceptors, and thinning of retina. This report describes the protective potential of a peptide derived from the ?B crystallin protein using a sodium iodate (NaIO3) induced mouse model of GA. Systemic NaIO3 challenge causes degeneration of the RPE and neighboring photoreceptors, which have similarities to retinas of GA patients. ?B crystallin is an abundant ocular protein that maintains ocular clarity and retinal homeostasis, and a small peptide from this protein (mini cry) displays neuroprotective properties. To retain this peptide for longer in the vitreous, mini cry was fused to an elastin-like polypeptide (ELP). A single intra-vitreal treatment by this crySI fusion significantly inhibits retinal degeneration in comparison to free mini cry. While mini cry is cleared from the eye with a mean residence time of 0.4?days, crySI is retained with a mean residence time of 3.0?days; furthermore, fundus photography reveals evidence of retention at two weeks. Unlike the free mini cry, crySI protects the RPE against NaIO3 challenge for at least two weeks after administration. CrySI also inhibits RPE apoptosis and caspase-3 activation and protects the retina from cell death up to 1-month post NaIO3 challenge. These results show that intra-ocular ELP-linked peptides such as crySI hold promise as protective agents to prevent RPE atrophy and progressive retinal degeneration in AMD.

SUBMITTER: Sreekumar PG

PROVIDER: S-EPMC6368441 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature

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Intra-vitreal αB crystallin fused to elastin-like polypeptide provides neuroprotection in a mouse model of age-related macular degeneration.

Sreekumar Parameswaran G PG Li Zhe Z Wang Wan W Spee Christine C Hinton David R DR Kannan Ram R MacKay J Andrew JA

Journal of controlled release : official journal of the Controlled Release Society 20180518

Age-related macular degeneration (AMD) is the leading cause of severe and irreversible central vision loss, and the primary site of AMD pathology is the retinal pigment epithelium (RPE). Geographic atrophy (GA) is an advanced form of AMD characterized by extensive RPE cell loss, subsequent degeneration of photoreceptors, and thinning of retina. This report describes the protective potential of a peptide derived from the αB crystallin protein using a sodium iodate (NaIO<sub>3</sub>) induced mouse ...[more]

PMID: 29778783

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Project description:?B crystallin is a chaperone protein with anti-apoptotic and anti-inflammatory functions and has been identified as a biomarker in age-related macular degeneration. The purpose of this study was to determine whether ?B crystallin is secreted from retinal pigment epithelial (RPE) cells, the mechanism of this secretory pathway and to determine whether extracellular ?B crystallin can be taken up by adjacent retinal cells and provide protection from oxidant stress. We used human RPE cells to establish that ?B crystallin is secreted by a non-classical pathway that involves exosomes. Evidence for the release of exosomes by RPE and localization of ?B crystallin within the exosomes was achieved by immunoblot, immunofluorescence, and electron microscopic analyses. Inhibition of lipid rafts or exosomes significantly reduced ?B crystallin secretion, while inhibitors of classic secretory pathways had no effect. In highly polarized RPE monolayers, ?B crystallin was selectively secreted towards the apical, photoreceptor-facing side. In support, confocal microscopy established that ?B crystallin was localized predominantly in the apical compartment of RPE monolayers, where it co-localized in part with exosomal marker CD63. Severe oxidative stress resulted in barrier breakdown and release of ?B crystallin to the basolateral side. In normal mouse retinal sections, ?B crystallin was identified in the interphotoreceptor matrix. An increased uptake of exogenous ?B crystallin and protection from apoptosis by inhibition of caspase 3 and PARP activation were observed in stressed RPE cultures. ?B Crystallin was taken up by photoreceptors in mouse retinal explants exposed to oxidative stress. These results demonstrate an important role for ?B crystallin in maintaining and facilitating a neuroprotective outer retinal environment and may also explain the accumulation of ?B crystallin in extracellular sub-RPE deposits in the stressed microenvironment in age-related macular degeneration. Thus evidence from our studies supports a neuroprotective role for ?B crystallin in ocular diseases.

Dataset Information

Intra-vitreal ?B crystallin fused to elastin-like polypeptide provides neuroprotection in a mouse model of age-related macular degeneration.

Publications

Intra-vitreal αB crystallin fused to elastin-like polypeptide provides neuroprotection in a mouse model of age-related macular degeneration.

Similar Datasets

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