Alpha-crystallin-mediated protection of lens cells against heat and oxidative stress-induced cell death

Christopher, Karen L; Pedler, Michelle G.; Shieh, Biehuoy; Ammar, David A.; Petrash, J. Mark; Mueller, Niklaus H.

doi:10.1016/j.bbamcr.2013.11.010

Cited by 52 publications

(39 citation statements)

References 34 publications

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“…While these approaches have resulted in varying success, we have hypothesized that replenishment of full-length α-crystallin in the lens will delay the onset of cataract by preventing protein aggregation. Additionally, we and others have previously shown these proteins prevent stress induced apoptosis [ 14 – 18 ].…”

Section: Introductionmentioning

confidence: 90%

Impact of Subunit Composition on the Uptake of α-Crystallin by Lens and Retina

et al. 2015

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Misfolded protein aggregation, including cataract, cause a significant amount of blindness worldwide. α-Crystallin is reported to bind misfolded proteins and prevent their aggregation. We hypothesize that supplementing retina and lens with α-crystallin may help to delay disease onset. The purpose of this study was to determine if αB-crystallin subunits containing a cell penetration peptide (gC-tagged αB-crystallin) facilitate the uptake of wild type αA-crystallin (WT-αA) in lens and retina. Recombinant human αB-crystallin was modified by the addition of a novel cell penetration peptide derived from the gC gene product of herpes simplex virus (gC-αB). Recombinant gC-αB and wild-type αA-crystallin (WT-αA) were purified from E. coli over-expression cultures. After Alexa-labeling of WT-αA, these proteins were mixed at ratios of 1:2, 1:5 and 1:10, respectively, and incubated at 37°C for 4 hours to allow for subunit exchange. Mixed oligomers were subsequently incubated with tissue culture cells or mouse organ cultures. Similarly, crystallin mixtures were injected into the vitreous of rat eyes. At various times after exposure, tissues were harvested and analyzed for protein uptake by confocal microscopy or flow cytometry. Chaperone-like activity assays were performed on α-crystallins ratios showing optimal uptake using chemically-induced or heat induced substrate aggregation assays. As determined by flow cytometry, a ratio of 1:5 for gC-αB to WT-αA was found to be optimal for uptake into retinal pigmented epithelial cells (ARPE-19). Chaperone-like activity assays demonstrated that hetero-oligomeric complex of gC-αB to WT-αA (in 1:5 ratio) retained protein aggregation protection. We observed a significant increase in protein uptake when optimized (gC-αB to WT-αA (1:5 ratio)) hetero-oligomers were used in mouse lens and retinal organ cultures. Increased levels of α-crystallin were found in lens and retina following intravitreal injection of homo- and hetero-oligomers in rats.

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Section: Introductionmentioning

confidence: 90%

Impact of Subunit Composition on the Uptake of α-Crystallin by Lens and Retina

et al. 2015

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“…Effects of esculetin or idebenone on lenticular expression levels of Bax and Bcl-2 integrity, aggregate lens crystallins causing lens opacity (Christopher et al, 2014), and apoptosis (Babizhayev, 2016).…”

Section: Ta B L Ementioning

confidence: 99%

Esculetin and idebenone ameliorate galactose‐induced cataract in a rat model

et al. 2020

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Cataract is the principal cause of blindness. The enzyme, aldose reductase (AR) is a key player in polyol pathway. Buildup of polyols and oxidative stress are the main causes of cataractogenesis. This study investigated the cytoprotective properties of esculetin and idebenone in galactose‐induced cataract. Rats were partitioned into four groups each of ten rats. Control group was fed with normal diet; group 2 rats were fed with galactose diet (50%); groups 3, 4 rats were fed with galactose diet concurrently with either esculetin (50 mg/kg BW) or idebenone (100 mg/kg BW), for 20 days. The study revealed that esculetin and idebenone significantly reduced the elevated levels of Bax/Bcl‐2 ratio, malondialdehyde, and DNA fragmentation and increased total antioxidant capacity level in lenses compared to the cataract‐induced group. Only esculetin decreased AR, galactitol, and advanced glycated end products levels in lenses. Histopathological examinations supported the biochemical findings. Esculetin and idebenone may have chemopreventive effects for sugar cataract. Practical applications Cataract is an age‐related disease that might cause blindness in older adult people. Presently, no absolute pharmacological treatment is accessible for cataract. The use of natural products or their derivatives attract particular attention in modern medicines as they are believed to be safer with few or no side effects. Esculetin is a polyphenolic compound found in many medicinal plants. Idebenone is a synthetic analogue of coenzyme Q10. The current study is an approach to explore the anticataract effects of esculetin and idebenone in galactose‐induced cataract in rats. Our study proved that both agents have anticataractogenic potentials due to their antioxidant and antiapoptotic properties.

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“…Karen L found the recombinant exogenous proteinswereco-localizedwith the native CRYAA in perinuclear regionsdetectedbyimmunohistochemistry [30]. The altered distributions incellularofCRYAA might contribute to the onset of ARC [21].…”

Section: Discussionmentioning

confidence: 99%

A novel silent mutation E83E of αA-crystallin in age-related cataract with impaired chaperone function

Song

Liu

Sun

et al. 2020

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Background Age-related cataract (ARC) is the leading cause of blindness of the aged, influenced by environmental factors and genetic factors. However, it is scanty in gene mutation studies. The study aims to expand knowledge of etiology of ARC. Methods Peripheral blood samples of ARC patients were collected to screen αA-crystallin (CRYAA) gene mutations by single strand conformation polymorphism assay. Cell morphology, protein expression level and chaperone function of CRYAA in HLE B-3 cell line influenced by mutant CRYAA were next analyzed. Chaperone function of mutant CRYAA was measured by aggregation assay in physiological status, heat treatment (42℃) and ultraviolet (UV) treatment. Cell morphology and protein expression level effected by UV in human lens epithelial B3 (HLE B-3) cells and human anterior lens capsules (ALCs) were further analyzed. Results We identified a novel silent mutation in CRYAA (c.249G > A, p.E83E) among 300 ARC patients. CRYAA-E83E may up-regulate the CRYAA expression levels of both mRNA and protein, and change the distribution of CRYAA in HLE B-3 cells. Compared to wild type CRYAA (CRYAA-WT), CRYAA-E83E showed lower chaperone function after 42℃ heat treatment and UV treatment. Meanwhile, after UV treatment, HLE B-3 cells and lens epithelial cells in human ALCs showed irregular and flatten morphology; decreased CRYAA expression levels; increased laminin γ2 expression levels, and changed epithelial-mesenchymal transition (EMT) related protein expression levels. Conclusions The E83E mutation of CRYAA is a potential pathogenic mutation, considering its influence on the expression level, intracellular distribution and chaperone function of CRYAA.

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Alpha-crystallin-mediated protection of lens cells against heat and oxidative stress-induced cell death

Cited by 52 publications

References 34 publications

Impact of Subunit Composition on the Uptake of α-Crystallin by Lens and Retina

Impact of Subunit Composition on the Uptake of α-Crystallin by Lens and Retina

Esculetin and idebenone ameliorate galactose‐induced cataract in a rat model

A novel silent mutation E83E of αA-crystallin in age-related cataract with impaired chaperone function

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