1
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Amer R, Koriat A. Aqueous humor perturbations in chronic smokers: a proteomic study. Sci Rep 2024; 14:11279. [PMID: 38760463 PMCID: PMC11101467 DOI: 10.1038/s41598-024-62039-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 05/13/2024] [Indexed: 05/19/2024] Open
Abstract
The detrimental effects of smoking are multisystemic and its effects on the eye health are significant. Smoking is a strong risk factor for age-related nuclear cataract, age-related macular degeneration, glaucoma, delayed corneal epithelial healing and increased risk of cystoid macular edema in patients with intermediate uveitis among others. We aimed to characterize the aqueous humor (AH) proteome in chronic smokers to gain insight into its perturbations and to identify potential biomarkers for smoking-associated ocular pathologies. Compared to the control group, chronic smokers displayed 67 (37 upregulated, 30 downregulated) differentially expressed proteins (DEPs). Analysis of DEPs from the biological point of view revealed that they were proteins involved in complement activation, lymphocyte mediated immunity, innate immune response, cellular oxidant detoxification, bicarbonate transport and platelet degranulation. From the molecular function point of view, DEPs were involved in oxygen binding, oxygen carrier activity, hemoglobin binding, peptidase/endopeptidase/cysteine-type endopeptidase inhibitory activity. Several of the upregulated proteins were acute phase reactant proteins such as clusterin, alpha-2-HS-glycoprotein, fibrinogen, alpha-1-antitrypsin, C4b-binding protein and serum amyloid A-2. Further research should confirm if these proteins might serve as biomarkers or therapeutic target for smoking-associated ocular diseases.
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Affiliation(s)
- Radgonde Amer
- Department of Ophthalmology, Hadassah Medical Center, Jerusalem, Israel.
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.
| | - Adi Koriat
- Department of Ophthalmology, Hadassah Medical Center, Jerusalem, Israel
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2
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Patil H, Yi H, Cho KI, Ferreira PA. Proteostatic Remodeling of Small Heat Shock Chaperones─Crystallins by Ran-Binding Protein 2─and the Peptidyl-Prolyl cis-trans Isomerase and Chaperone Activities of Its Cyclophilin Domain. ACS Chem Neurosci 2024; 15:1967-1989. [PMID: 38657106 DOI: 10.1021/acschemneuro.3c00792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024] Open
Abstract
Disturbances in protein phase transitions promote protein aggregation─a neurodegeneration hallmark. The modular Ran-binding protein 2 (Ranbp2) is a cytosolic molecular hub for rate-limiting steps of phase transitions of Ran-GTP-bound protein ensembles exiting nuclear pores. Chaperones also regulate phase transitions and proteostasis by suppressing protein aggregation. Ranbp2 haploinsufficiency promotes the age-dependent neuroprotection of the chorioretina against phototoxicity by proteostatic regulations of neuroprotective substrates of Ranbp2 and by suppressing the buildup of polyubiquitylated substrates. Losses of peptidyl-prolyl cis-trans isomerase (PPIase) and chaperone activities of the cyclophilin domain (CY) of Ranbp2 recapitulate molecular effects of Ranbp2 haploinsufficiency. These CY impairments also stimulate deubiquitylation activities and phase transitions of 19S cap subunits of the 26S proteasome that associates with Ranbp2. However, links between CY moonlighting activity, substrate ubiquitylation, and proteostasis remain incomplete. Here, we reveal the Ranbp2 regulation of small heat shock chaperones─crystallins in the chorioretina by proteomics of mice with total or selective modular deficits of Ranbp2. Specifically, loss of CY PPIase of Ranbp2 upregulates αA-Crystallin, which is repressed in adult nonlenticular tissues. Conversely, impairment of CY's chaperone activity opposite to the PPIase pocket downregulates a subset of αA-Crystallin's substrates, γ-crystallins. These CY-dependent effects cause age-dependent and chorioretinal-selective declines of ubiquitylated substrates without affecting the chorioretinal morphology. A model emerges whereby inhibition of Ranbp2's CY PPIase remodels crystallins' expressions, subdues molecular aging, and preordains the chorioretina to neuroprotection by augmenting the chaperone capacity and the degradation of polyubiquitylated substrates against proteostatic impairments. Further, the druggable Ranbp2 CY holds pan-therapeutic potential against proteotoxicity and neurodegeneration.
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Affiliation(s)
- Hemangi Patil
- Department of Ophthalmology Duke University Medical Center, Durham, North Carolina 27710, United States
| | - Haiqing Yi
- Department of Ophthalmology Duke University Medical Center, Durham, North Carolina 27710, United States
| | - Kyoung-In Cho
- Department of Ophthalmology Duke University Medical Center, Durham, North Carolina 27710, United States
| | - Paulo A Ferreira
- Department of Ophthalmology Duke University Medical Center, Durham, North Carolina 27710, United States
- Department of Pathology Duke University Medical Center, Durham, North Carolina 27710, United States
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3
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Posner M, Garver T, Kaye T, Brdicka S, Suttle M, Patterson B, Farnsworth DR. Loss of αBa-crystallin, but not αA-crystallin, increases age-related cataract in the zebrafish lens. Exp Eye Res 2024; 244:109918. [PMID: 38705506 DOI: 10.1016/j.exer.2024.109918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 04/26/2024] [Accepted: 04/29/2024] [Indexed: 05/07/2024]
Abstract
The vertebrate eye lens is an unusual organ in that most of its cells lack nuclei and the ability to replace aging protein. The small heat shock protein α-crystallins evolved to become key components of this lens, possibly because of their ability to prevent aggregation of aging protein that would otherwise lead to lens opacity. Most vertebrates express two α-crystallins, αA- and αB-crystallin, and mutations in each are linked to human cataract. In a mouse knockout model only the loss of αA-crystallin led to early-stage lens cataract. We have used the zebrafish as a model system to investigate the role of α-crystallins during lens development. Interestingly, while zebrafish express one lens-specific αA-crystallin gene (cryaa), they express two αB-crystallin genes, with one evolving lens specificity (cryaba) and the other retaining the broad expression of its mammalian ortholog (cryabb). In this study we used individual mutant zebrafish lines for all three α-crystallin genes to determine the impact of their loss on age-related cataract. Surprisingly, unlike mouse knockout models, we found that the loss of the αBa-crystallin gene cryaba led to an increase in lens opacity compared to cryaa null fish at 24 months of age. Loss of αA-crystallin did not increase the prevalence of cataract. We also used single cell RNA-Seq and RT-qPCR data to show a shift in the lens expression of zebrafish α-crystallins between 5 and 10 days post fertilization (dpf), with 5 and 6 dpf lenses expressing cryaa almost exclusively, and expression of cryaba and cryabb becoming more prominent after 10 dpf. These data show that cryaa is the primary α-crystallin during early lens development, while the protective role for cryaba becomes more important during lens aging. This study is the first to quantify cataract prevalence in wild-type aging zebrafish, showing that lens opacities develop in approximately 25% of fish by 18 months of age. None of the three α-crystallin mutants showed a compensatory increase in the expression of the remaining two crystallins, or in the abundant βB1-crystallin. Overall, these findings indicate an ontogenetic shift in the functional importance of individual α-crystallins during zebrafish lens development. Our finding that the lens-specific zebrafish αBa-crystallin plays the leading role in preventing age-related cataract adds a new twist to our understanding of vertebrate lens evolution.
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Affiliation(s)
- Mason Posner
- Department of Biology and Toxicology, Ashland University, Ashland, OH, USA.
| | - Taylor Garver
- Department of Biology and Toxicology, Ashland University, Ashland, OH, USA
| | - Taylor Kaye
- Department of Biology and Toxicology, Ashland University, Ashland, OH, USA
| | - Stuart Brdicka
- Department of Biology and Toxicology, Ashland University, Ashland, OH, USA
| | - Madison Suttle
- Department of Biology and Toxicology, Ashland University, Ashland, OH, USA
| | - Bryce Patterson
- Department of Biology and Toxicology, Ashland University, Ashland, OH, USA
| | - Dylan R Farnsworth
- The RNA Institute, University at Albany, State University of New York, Albany, NY, USA
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4
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Patil H, Cho KI, Ferreira PA. Proteostatic remodeling of small heat shock chaperones - crystallins by Ran-binding protein 2 and the peptidyl-prolyl cis-trans isomerase and chaperone activities of its cyclophilin domain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.26.577462. [PMID: 38352504 PMCID: PMC10862737 DOI: 10.1101/2024.01.26.577462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2024]
Abstract
Disturbances in phase transitions and intracellular partitions of nucleocytoplasmic shuttling substrates promote protein aggregation - a hallmark of neurodegenerative diseases. The modular Ran-binding protein 2 (Ranbp2) is a cytosolic molecular hub for rate-limiting steps of disassembly and phase transitions of Ran-GTP-bound protein ensembles exiting nuclear pores. Chaperones also play central roles in phase transitions and proteostasis by suppressing protein aggregation. Ranbp2 haploinsufficiency promotes the age-dependent neuroprotection of the chorioretina against photo-oxidative stress by proteostatic regulations of Ranbp2 substrates and by countering the build-up of poly-ubiquitylated substrates. Further, the peptidyl-prolyl cis-trans isomerase (PPIase) and chaperone activities of the cyclophilin domain (CY) of Ranbp2 modulate the proteostasis of selective neuroprotective substrates, such as hnRNPA2B1, STAT3, HDAC4 or L/M-opsin, while promoting a decline of ubiquitylated substrates. However, links between CY PPIase activity on client substrates and its effect(s) on ubiquitylated substrates are unclear. Here, proteomics of genetically modified mice with deficits of Ranbp2 uncovered the regulation of the small heat shock chaperones - crystallins by Ranbp2 in the chorioretina. Loss of CY PPIase of Ranbp2 up-regulates αA-crystallin proteostasis, which is repressed in non-lenticular tissues. Conversely, the αA-crystallin's substrates, γ-crystallins, are down-regulated by impairment of CY's C-terminal chaperone activity. These CY-dependent effects cause the age-dependent decline of ubiquitylated substrates without overt chorioretinal morphological changes. A model emerges whereby the Ranbp2 CY-dependent remodeling of crystallins' proteostasis subdues molecular aging and preordains chorioretinal neuroprotection by augmenting the chaperone buffering capacity and the decline of ubiquitylated substrates against proteostatic impairments. Further, CY's moonlighting activity holds pan -therapeutic potential against neurodegeneration.
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5
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Posner M, Garver T, Kaye T, Brdicka S, Suttle M, Patterson B, Farnsworth DR. Loss of αBa-crystallin, but not αA-crystallin, increases age-related cataract in the zebrafish lens. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.03.574085. [PMID: 38260567 PMCID: PMC10802301 DOI: 10.1101/2024.01.03.574085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The vertebrate eye lens is an unusual organ in that most of its cells lack nuclei and the ability to replace aging protein. The small heat shock protein α-crystallins evolved to become key components of this lens, possibly because of their ability to prevent aggregation of aging protein that would otherwise lead to lens opacity. Most vertebrates express two α-crystallins, αA- and αB-crystallin, and mutations in each are linked to human cataract. In a mouse knockout model only the loss of αA-crystallin led to early-stage lens cataract. We have used the zebrafish as a model system to investigate the role of α-crystallins during lens development. Interestingly, while zebrafish express one lens-specific αA-crystallin gene (cryaa), they express two αB-crystallin genes, with one evolving lens specificity (cryaba) and the other retaining the broad expression of its mammalian ortholog (cryabb). In this study we used individual mutant zebrafish lines for all three α-crystallin genes to determine the impact of their loss on age-related cataract. Surprisingly, unlike mouse knockout models, we found that the loss of the αBa-crystallin gene cryaba led to an increase in lens opacity compared to cryaa null fish at 24 months of age. Loss of αA-crystallin did not increase the prevalence of cataract. We also used single cell RNA-Seq and RT-qPCR data to show a shift in the lens expression of zebrafish α-crystallins between 5 and 10 days post fertilization (dpf), with 5 and 6 dpf lenses expressing cryaa almost exclusively, and expression of cryaba and cryabb becoming more prominent after 10 dpf. These data show that cryaa is the primary α-crystallin during early lens development, while the protective role for cryaba becomes more important during lens aging. This study is the first to quantify cataract prevalence in wild-type zebrafish, showing that lens opacities develop in approximately 25% of fish by 18 months of age. None of the three α-crystallin mutants showed a compensatory increase in the expression of the remaining two crystallins, or in the abundant βB1-crystallin. Overall, these findings indicate an ontogenetic shift in the functional importance of individual α-crystallins during zebrafish lens development. Our finding that the lens-specific zebrafish αBa-crystallin plays the leading role in preventing age-related cataract adds a new twist to our understanding of vertebrate lens evolution.
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Affiliation(s)
- Mason Posner
- Department of Biology and Toxicology, Ashland University, Ashland, OH
| | - Taylor Garver
- Department of Biology and Toxicology, Ashland University, Ashland, OH
| | - Taylor Kaye
- Department of Biology and Toxicology, Ashland University, Ashland, OH
| | - Stuart Brdicka
- Department of Biology and Toxicology, Ashland University, Ashland, OH
| | - Madison Suttle
- Department of Biology and Toxicology, Ashland University, Ashland, OH
| | - Bryce Patterson
- Department of Biology and Toxicology, Ashland University, Ashland, OH
| | - Dylan R. Farnsworth
- The RNA InsRtute, University at Albany, State University of New York, Albany, NY
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6
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Khidiyatova I, Khidiyatova I, Zinchenko R, Marakhonov A, Karunas A, Avkhadeeva S, Aznzbaev M, Khusnutdinova E. Study of The Molecular Nature of Congenital Cataracts in Patients from The Volga-Ural Region. Curr Issues Mol Biol 2023; 45:5145-5163. [PMID: 37367076 DOI: 10.3390/cimb45060327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 06/05/2023] [Accepted: 06/09/2023] [Indexed: 06/28/2023] Open
Abstract
Hereditary cataracts are characterized by significant clinical and genetic heterogeneity, which can pose challenges for early DNA diagnosis. To comprehensively address this problem, it is essential to investigate the epidemiology of the disease, perform population studies to determine the spectrum and frequencies of mutations in the responsible genes, and examine clinical and genetic correlations. Based on modern concepts, non-syndromic hereditary cataracts are predominantly caused by genetic disease forms associated with mutations in crystallin and connexin genes. Therefore, a comprehensive approach to studying hereditary cataracts is necessary for early diagnosis and improved treatment outcomes. The crystallin (CRYAA, CRYAB, CRYGC, CRYGD, and CRYBA1) and connexin (GJA8, GJA3) genes were analyzed in 45 unrelated families from the Volga-Ural Region (VUR) with hereditary congenital cataracts. Pathogenic and probably pathogenic nucleotide variants were identified in ten unrelated families, nine of which had cataracts in an autosomal dominant pattern of inheritance. Two previously undescribed likely pathogenic missense variants were identified in the CRYAA gene: c.253C > T (p.L85F) in one family and c.291C > G (p.H97Q) in two families. The known mutation c.272_274delGAG (p.G91del) was found in the CRYBA1 gene in one family, while no pathogenic variants were found in the CRYAB, CRYGC, or CRYGD genes in the examined patients. In the GJA8 gene, the known mutation c.68G > C (p.R23T) was found in two families, and previously undescribed variants were identified in two other families: a c.133_142del deletion (p.W45Sfs*72) and a missense variant, c.179G > A (p.G60D). In one patient with a recessive form of cataract, two compound-heterozygous variants were identified-a previously undescribed likely pathogenic missense variant, c.143A > G (p.E48G), and a known variant with uncertain pathogenetic significance, c.741T > G (p.I24M). Additionally, a previously undescribed deletion, c.del1126_1139 (p.D376Qfs*69), was identified in the GJA3 gene in one family. In all families where mutations were identified, cataracts were diagnosed either immediately after birth or during the first year of life. The clinical presentation of the cataracts varied depending on the type of lens opacity, resulting in various clinical forms. This information emphasizes the importance of early diagnosis and genetic testing for hereditary congenital cataracts to guide appropriate management and improve outcomes.
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Affiliation(s)
- Irina Khidiyatova
- Institute of Biochemistry and Genetics-Subdivision of the Ufa Federal Research Centre of the Russian Academy of Sciences, 450054 Ufa, Russia
- Department of Biology, Bashkir State University, 450076 Ufa, Russia
| | - Indira Khidiyatova
- Institute of Biochemistry and Genetics-Subdivision of the Ufa Federal Research Centre of the Russian Academy of Sciences, 450054 Ufa, Russia
| | - Rena Zinchenko
- Research Centre for Medical Genetics, 115522 Moscow, Russia
| | | | - Alexandra Karunas
- Institute of Biochemistry and Genetics-Subdivision of the Ufa Federal Research Centre of the Russian Academy of Sciences, 450054 Ufa, Russia
- Medical Faculty, Bashkir State Medical University, 450000 Ufa, Russia
| | | | - Marat Aznzbaev
- Medical Faculty, Bashkir State Medical University, 450000 Ufa, Russia
| | - Elza Khusnutdinova
- Institute of Biochemistry and Genetics-Subdivision of the Ufa Federal Research Centre of the Russian Academy of Sciences, 450054 Ufa, Russia
- Department of Biology, Bashkir State University, 450076 Ufa, Russia
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7
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Ma X, Nan Y, Huang C, Li X, Yang Y, Jiang W, Ye M, Liu Q, Niu Y, Yuan L. Expression of αA-crystallin (CRYAA) in vivo and in vitro models of age-related cataract and the effect of its silencing on HLEB3 cells. Aging (Albany NY) 2023; 15:204754. [PMID: 37253645 DOI: 10.18632/aging.204754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Accepted: 05/16/2023] [Indexed: 06/01/2023]
Abstract
AIM To investigate the expression of αA-crystallin (CRYAA) in age-related cataract (ARC) models and its role in lens epithelial cells (LECs). METHODS We used Flow cytometry to detect the apoptosis and cell cycle in HLEB3 cells and Real-time fluorescence quantitative polymerase chain reaction to detect the expression of CRYAA mRNA in HLEB3 and in rabbit lens. The expression of CRYAA in HLEB3 cells and rabbit lenses as well as the proteins related to apoptosis and autophagy in transfected cells were detected by western blotting. The lens structure in rabbits was investigated using hematoxylin-eosin staining. Protein thermostability assay was performed to detect the thermal stability of rabbit lens proteins. CCK- 8 assay was used to detect the viability of transfected cells, and the transfection was recorded by fluorescence photography. RESULTS Hydrogen peroxide can promote apoptosis and arrest the cell cycle in HLEB3 cells, and naphthalene can cause cataract formation and damage the structure of the lens in rabbits. Both ARC models can reduce the expression of CRYAA. The expression of CRYAA silencing increased apoptosis and autophagy in HLEB3 cells.
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Affiliation(s)
- Xiaoling Ma
- Ningxia Medical University Key Laboratory of Ningxia Minority Medicine Modernization Ministry of Education, Ningxia Medical University, Yinchuan 750004, Ningxia, China
| | - Yi Nan
- Ningxia Medical University Key Laboratory of Ningxia Minority Medicine Modernization Ministry of Education, Ningxia Medical University, Yinchuan 750004, Ningxia, China
| | - Can Huang
- Ningxia Medical University Key Laboratory of Ningxia Minority Medicine Modernization Ministry of Education, Ningxia Medical University, Yinchuan 750004, Ningxia, China
| | - Xiangyang Li
- School of Traditional Chinese Medicine, Ningxia Medical University, Yinchuan 750004, Ningxia, China
| | - Yifan Yang
- Ningxia Medical University Key Laboratory of Ningxia Minority Medicine Modernization Ministry of Education, Ningxia Medical University, Yinchuan 750004, Ningxia, China
| | - Wenjie Jiang
- Ningxia Medical University Key Laboratory of Ningxia Minority Medicine Modernization Ministry of Education, Ningxia Medical University, Yinchuan 750004, Ningxia, China
| | - Mengyi Ye
- School of Traditional Chinese Medicine, Ningxia Medical University, Yinchuan 750004, Ningxia, China
| | - Qian Liu
- School of Clinical Medicine, Ningxia Medical University, Yinchuan 750004, Ningxia, China
| | - Yang Niu
- Ningxia Medical University Key Laboratory of Ningxia Minority Medicine Modernization Ministry of Education, Ningxia Medical University, Yinchuan 750004, Ningxia, China
- School of Traditional Chinese Medicine, Ningxia Medical University, Yinchuan 750004, Ningxia, China
| | - Ling Yuan
- Ningxia Medical University Key Laboratory of Ningxia Minority Medicine Modernization Ministry of Education, Ningxia Medical University, Yinchuan 750004, Ningxia, China
- School of Pharmacy, Ningxia Medical University, Yinchuan 750004, Ningxia Hui Autonomous Region, China
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8
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Zhao Z, Chen J, Yuan W, Jiang Y, Lu Y. Association between single nucleotide polymorphisms in exon 3 of the alpha-A-crystallin gene and susceptibility to age-related cataract. Ophthalmic Genet 2023; 44:127-132. [PMID: 36380611 DOI: 10.1080/13816810.2022.2092757] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND The mutations in the αA-crystallin (CRYAA) gene may contribute to the development of age-related cataract (ARC). In this study, we searched for single nucleotide polymorphisms (SNP) in exons of CRYAA and investigated the associations between the identified SNPs and the subtypes of ARC. MATERIALS AND METHODS Peripheral venous blood was collected for the extraction of genomic DNA. Three exons of CRYAA were sequenced to detect SNPs. The frequency distributions of alleles and genotypes were compared between the ARC and control groups. RESULTS There were 618 patients with various subtypes of ARC (nuclear cataract [NC], cortical cataract [CC], posterior subcapsular cataract [PSC]). The control group comprised 236 patients. The incidence of early-onset cataract was significantly greater in PSC patients (P = .002 for NC; P = .036 for CC). One SNP was detected in exon 3 of CRYAA (rs76740365 G>A). When the distribution of rs76740365 was compared among the ARC subtypes, only the difference between the PSC group and the control group was statistically significant (allele frequency: P = .000057, OR 2.945; genotype distribution frequency: P = .000458). The heterozygote genotype (GA) carried a significantly greater risk than the homozygous wild-type genotype (GG) by 1.742 times for all types of cataracts and 2.369 times for the PSC subtype. CONCLUSIONS The SNP rs76740365 G>A in exon 3 of the CRYAA gene is associated with greater susceptibility of ARC, particularly the PSC subtype. Individuals carrying the SNP rs76740365 G>A may be more likely to develop PSC at a younger age than other subtypes.
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Affiliation(s)
- Zhennan Zhao
- Department of Ophthalmology and Vision Science, Eye Ear Nose and Throat Hospital of Fudan University, Shanghai, China
- National Health Commission Key Laboratory of Myopia (Fudan University), Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Key Laboratory of Visual Impairment and Restoration of Shanghai, Shanghai, China
| | - Jiahui Chen
- Department of Ophthalmology and Vision Science, Eye Ear Nose and Throat Hospital of Fudan University, Shanghai, China
- National Health Commission Key Laboratory of Myopia (Fudan University), Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Key Laboratory of Visual Impairment and Restoration of Shanghai, Shanghai, China
| | - Wenyi Yuan
- Department of Ophthalmology and Vision Science, Eye Ear Nose and Throat Hospital of Fudan University, Shanghai, China
- National Health Commission Key Laboratory of Myopia (Fudan University), Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Key Laboratory of Visual Impairment and Restoration of Shanghai, Shanghai, China
| | - Yongxiang Jiang
- Department of Ophthalmology and Vision Science, Eye Ear Nose and Throat Hospital of Fudan University, Shanghai, China
- National Health Commission Key Laboratory of Myopia (Fudan University), Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Key Laboratory of Visual Impairment and Restoration of Shanghai, Shanghai, China
| | - Yi Lu
- Department of Ophthalmology and Vision Science, Eye Ear Nose and Throat Hospital of Fudan University, Shanghai, China
- National Health Commission Key Laboratory of Myopia (Fudan University), Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Key Laboratory of Visual Impairment and Restoration of Shanghai, Shanghai, China
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9
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A tapt1 knock-out zebrafish line with aberrant lens development and impaired vision models human early-onset cataract. Hum Genet 2023; 142:457-476. [PMID: 36697720 DOI: 10.1007/s00439-022-02518-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 12/19/2022] [Indexed: 01/27/2023]
Abstract
Bi-allelic mutations in the gene coding for human trans-membrane anterior-posterior transformation protein 1 (TAPT1) result in a broad phenotypic spectrum, ranging from syndromic disease with severe skeletal and congenital abnormalities to isolated early-onset cataract. We present here the first patient with a frameshift mutation in the TAPT1 gene, resulting in both bilateral early-onset cataract and skeletal abnormalities, in addition to several dysmorphic features, in this way further expanding the phenotypic spectrum associated with TAPT1 mutations. A tapt1a/tapt1b double knock-out (KO) zebrafish model generated by CRISPR/Cas9 gene editing revealed an early larval phenotype with eye malformations, loss of vision, increased photokinetics and hyperpigmentation, without visible skeletal involvement. Ultrastructural analysis of the eyes showed a smaller condensed lens, loss of integrity of the lens capsule with formation of a secondary lens and hyperplasia of the cells in the ganglion and inner plexiform layers of the retina. Transcriptomic analysis pointed to an impaired lens development with aberrant expression of many of the crystallin and other lens-specific genes. Furthermore, the phototransduction and visual perception pathways were found to be significantly disturbed. Differences in light perception are likely the cause of the increased dark photokinetics and generalized hyperpigmentation observed in this zebrafish model. In conclusion, this study validates TAPT1 as a new gene for early-onset cataract and sheds light on its ultrastructural and molecular characteristics.
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10
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Posner M, Murray KL, Andrew B, Brdicka S, Roberts A, Franklin K, Hussen A, Kaye T, Kepp E, McDonald MS, Snodgrass T, Zientek K, David LL. Impact of α-crystallin protein loss on zebrafish lens development. Exp Eye Res 2023; 227:109358. [PMID: 36572168 PMCID: PMC9918708 DOI: 10.1016/j.exer.2022.109358] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 11/27/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
The α-crystallin small heat shock proteins contribute to the transparency and refractive properties of the vertebrate eye lens and prevent the protein aggregation that would otherwise produce lens cataracts, the leading cause of human blindness. There are conflicting data in the literature as to what role the α-crystallins may play in early lens development. In this study, we used CRISPR gene editing to produce zebrafish lines with mutations in each of the three α-crystallin genes (cryaa, cryaba and cryabb) to prevent protein production. The absence of each α-crystallin protein was analyzed by mass spectrometry, and lens phenotypes were assessed with differential interference contrast microscopy and histology. Loss of αA-crystallin produced a variety of lens defects with varying severity in larvae at 3 and 4 dpf but little substantial change in normal fiber cell denucleation. Loss of αBa-crystallin produced no substantial lens defects. Our cryabb mutant produced a truncated αBb-crystallin protein and showed no substantial change in lens development. Mutation of each α-crystallin gene did not alter the mRNA levels of the remaining two, suggesting a lack of genetic compensation. These data suggest that αA-crystallin plays some role in lens development, but the range of phenotype severity in null mutants indicates its loss simply increases the chance for defects and that the protein is not essential. Our finding that cryaba and cryabb mutants lack noticeable lens defects is congruent with insubstantial transcript levels for these genes in lens epithelial and fiber cells through five days of development. Future experiments can explore the molecular mechanisms leading to lens defects in cryaa null mutants and the impact of αA-crystallin loss during zebrafish lens aging.
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Affiliation(s)
- Mason Posner
- Department of Biology and Toxicology, Ashland University, Ashland, OH, USA.
| | - Kelly L Murray
- Department of Biology and Toxicology, Ashland University, Ashland, OH, USA
| | - Brandon Andrew
- Department of Biology and Toxicology, Ashland University, Ashland, OH, USA
| | - Stuart Brdicka
- Department of Biology and Toxicology, Ashland University, Ashland, OH, USA
| | - Alexis Roberts
- Department of Biology and Toxicology, Ashland University, Ashland, OH, USA
| | - Kirstan Franklin
- Department of Biology and Toxicology, Ashland University, Ashland, OH, USA
| | - Adil Hussen
- Department of Biology and Toxicology, Ashland University, Ashland, OH, USA
| | - Taylor Kaye
- Department of Biology and Toxicology, Ashland University, Ashland, OH, USA
| | - Emmaline Kepp
- Department of Biology and Toxicology, Ashland University, Ashland, OH, USA
| | - Mathew S McDonald
- Department of Biology and Toxicology, Ashland University, Ashland, OH, USA
| | - Tyler Snodgrass
- Department of Biology and Toxicology, Ashland University, Ashland, OH, USA
| | - Keith Zientek
- Department of Chemical Physiology & Biochemistry, Oregon Health and Science University, USA
| | - Larry L David
- Department of Chemical Physiology & Biochemistry, Oregon Health and Science University, USA
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11
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Zhao Z, Sun Y, Fan Q, Jiang Y, Lu Y. Structural and functional analysis of SNP rs76740365 G>A in exon-3 of the alpha A-crystallin gene in lens epithelial cells. Mol Vis 2022; 28:317-330. [PMID: 36338667 PMCID: PMC9603911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 09/28/2022] [Indexed: 11/16/2022] Open
Abstract
Purpose To clarify the effect of a previously identified single nucleotide polymorphism (SNP; rs76740365 G>A) in the exon-3 of the alpha A-crystallin (CRYAA) gene on the properties of CRYAA and to investigate its function in human lens epithelial cells (HLECs). Methods The human recombinant wild-type and mutant CRYAA (E156K) were constructed, and the molecular weight was measured by mass spectrometry. The structural changes induced by E156K mutation were analyzed by UV circular dichroism spectra and intrinsic tryptophan fluorescence and were predicted using Schrödinger software. The chaperone-like ability of wild-type and E156K mutant CRYAA was invested against the heat-induced aggregation of βL-crystallin and the DTT-induced aggregation of insulin. HLECs expressing wild-type and mutated CRYAA were subjected to quantitative PCR (qPCR) and western blot. Cell apoptosis was determined using flow cytometry analysis, and the expression of apoptosis-related proteins were determined using western blot. Results The mass spectrometric detection revealed that E156K mutation had no significant effect on the apparent molecular mass of the CRYAA oligomeric complex. Evaluation of the structures of the CRYAA indicated that E156K mutation did not significantly affect the secondary structures, while causing perturbations of the tertiary structure. The mutant CRYAA displayed an increase in chaperone-like activity, which might be related to the increase of the surface hydrophobicity. We also predicted that E156K mutation would induce a change from negatively charged surface to positively charged, which was the possible reason for the disturbance to the surface hydrophobicity. Transfection studies of HLECs revealed that the E156K mutant induced anti-apoptotic function in HLECs, which was possibly associated with the activation of the p-AKT signal pathway and downregulation of Casepase3. Conclusions Taken together, our results for the first time showed that E156K mutation in CRYAA associated with ARC resulted in enhanced chaperone-like function by inducing its surface hydrophobicity, which was directly related to the activation of its anti-apoptotic function.
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Affiliation(s)
- Zhennan Zhao
- Department of Ophthalmology and Vision Science, Eye Ear Nose and Throat Hospital of Fudan University, Shanghai, China,Key Laboratory of Visual Impairment and Restoration of Shanghai, Shanghai, China
| | - Yang Sun
- Department of Ophthalmology and Vision Science, Eye Ear Nose and Throat Hospital of Fudan University, Shanghai, China,Key Laboratory of Visual Impairment and Restoration of Shanghai, Shanghai, China
| | - Qi Fan
- Department of Ophthalmology and Vision Science, Eye Ear Nose and Throat Hospital of Fudan University, Shanghai, China,Key Laboratory of Visual Impairment and Restoration of Shanghai, Shanghai, China
| | - Yongxiang Jiang
- Department of Ophthalmology and Vision Science, Eye Ear Nose and Throat Hospital of Fudan University, Shanghai, China,Key Laboratory of Visual Impairment and Restoration of Shanghai, Shanghai, China
| | - Yi Lu
- Department of Ophthalmology and Vision Science, Eye Ear Nose and Throat Hospital of Fudan University, Shanghai, China,Key Laboratory of Visual Impairment and Restoration of Shanghai, Shanghai, China
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12
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Ruiss M, Findl O, Kronschläger M. The human lens: An antioxidant-dependent tissue revealed by the role of caffeine. Ageing Res Rev 2022; 79:101664. [PMID: 35690384 DOI: 10.1016/j.arr.2022.101664] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/24/2022] [Accepted: 06/04/2022] [Indexed: 11/01/2022]
Abstract
Cataract is the leading cause of blindness worldwide and surgery is the only option to treat the disease. Although the surgery is considered to be relatively safe, complications may occur in a subset of patients and access to ophthalmic care may be limited. Due to a growing and ageing population, an increase in cataract prevalence is expected and its management will become a socioeconomic challenge. Hence, there is a need for an alternative to cataract surgery. It is well known that oxidative stress is one of the main pathological processes leading to the generation of the disease. Antioxidant supplementation may, therefore, be a strategy to delay or to prevent the progression of cataract. Caffeine is a widely consumed high-potency antioxidant and may be of interest for the prevention of the disease. This review aims to give an overview of the anatomy and function of the lens, its antioxidant and reactive oxygen species (ROS) composition, and the role of oxidative stress in cataractogenesis. Also, the pharmacokinetics and -dynamics of caffeine will be described and the literature will be reviewed to give an overview of its anti-cataract potential and its possible role in the prevention of the disease.
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Affiliation(s)
- Manuel Ruiss
- Vienna Institute for Research in Ocular Surgery (VIROS), a Karl Landsteiner Institute, Department of Ophthalmology, Hanusch Hospital, Vienna 1140 Austria.
| | - Oliver Findl
- Vienna Institute for Research in Ocular Surgery (VIROS), a Karl Landsteiner Institute, Department of Ophthalmology, Hanusch Hospital, Vienna 1140 Austria.
| | - Martin Kronschläger
- Vienna Institute for Research in Ocular Surgery (VIROS), a Karl Landsteiner Institute, Department of Ophthalmology, Hanusch Hospital, Vienna 1140 Austria.
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13
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Evidence for Paracrine Protective Role of Exogenous αA-Crystallin in Retinal Ganglion Cells. eNeuro 2022; 9:ENEURO.0045-22.2022. [PMID: 35168949 PMCID: PMC8906792 DOI: 10.1523/eneuro.0045-22.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 02/02/2022] [Indexed: 12/11/2022] Open
Abstract
Expression and secretion of neurotrophic factors have long been known as a key mechanism of neuroglial interaction in the central nervous system. In addition, several other intrinsic neuroprotective pathways have been described, including those involving small heat shock proteins such as α-crystallins. While initially considered as a purely intracellular mechanism, both αA-crystallins and αB-crystallins have been recently reported to be secreted by glial cells. While an anti-apoptotic effect of such secreted αA-crystallin has been suggested, its regulation and protective potential remain unclear. We recently identified residue threonine 148 (T148) and its phosphorylation as a critical regulator of αA-crystallin intrinsic neuroprotective function. In the current study, we explored how mutation of this residue affected αA-crystallin chaperone function, secretion, and paracrine protective function using primary glial and neuronal cells. After demonstrating the paracrine protective effect of αA-crystallins secreted by primary Müller glial cells (MGCs), we purified and characterized recombinant αA-crystallin proteins mutated on the T148 regulatory residue. Characterization of the biochemical properties of these mutants revealed an increased chaperone activity of the phosphomimetic T148D mutant. Consistent with this observation, we also show that exogeneous supplementation of the phosphomimetic T148D mutant protein protected primary retinal neurons from metabolic stress despite similar cellular uptake. In contrast, the nonphosphorylatable mutant was completely ineffective. Altogether, our study demonstrates the paracrine role of αA-crystallin in the central nervous system as well as the therapeutic potential of functionally enhanced αA-crystallin recombinant proteins to prevent metabolic-stress induced neurodegeneration.
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14
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Tedesco B, Cristofani R, Ferrari V, Cozzi M, Rusmini P, Casarotto E, Chierichetti M, Mina F, Galbiati M, Piccolella M, Crippa V, Poletti A. Insights on Human Small Heat Shock Proteins and Their Alterations in Diseases. Front Mol Biosci 2022; 9:842149. [PMID: 35281256 PMCID: PMC8913478 DOI: 10.3389/fmolb.2022.842149] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 01/19/2022] [Indexed: 11/13/2022] Open
Abstract
The family of the human small Heat Shock Proteins (HSPBs) consists of ten members of chaperones (HSPB1-HSPB10), characterized by a low molecular weight and capable of dimerization and oligomerization forming large homo- or hetero-complexes. All HSPBs possess a highly conserved centrally located α-crystallin domain and poorly conserved N- and C-terminal domains. The main feature of HSPBs is to exert cytoprotective functions by preserving proteostasis, assuring the structural maintenance of the cytoskeleton and acting in response to cellular stresses and apoptosis. HSPBs take part in cell homeostasis by acting as holdases, which is the ability to interact with a substrate preventing its aggregation. In addition, HSPBs cooperate in substrates refolding driven by other chaperones or, alternatively, promote substrate routing to degradation. Notably, while some HSPBs are ubiquitously expressed, others show peculiar tissue-specific expression. Cardiac muscle, skeletal muscle and neurons show high expression levels for a wide variety of HSPBs. Indeed, most of the mutations identified in HSPBs are associated to cardiomyopathies, myopathies, and motor neuropathies. Instead, mutations in HSPB4 and HSPB5, which are also expressed in lens, have been associated with cataract. Mutations of HSPBs family members encompass base substitutions, insertions, and deletions, resulting in single amino acid substitutions or in the generation of truncated or elongated proteins. This review will provide an updated overview of disease-related mutations in HSPBs focusing on the structural and biochemical effects of mutations and their functional consequences.
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Affiliation(s)
- B. Tedesco
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - R. Cristofani
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - V. Ferrari
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - M. Cozzi
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - P. Rusmini
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - E. Casarotto
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - M. Chierichetti
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - F. Mina
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - M. Galbiati
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - M. Piccolella
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - V. Crippa
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - A. Poletti
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
- *Correspondence: A. Poletti,
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15
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Fox SC, Widen SA, Asai-Coakwell M, Havrylov S, Benson M, Prichard LB, Baddam P, Graf D, Lehmann OJ, Waskiewicz AJ. BMP3 is a novel locus involved in the causality of ocular coloboma. Hum Genet 2022; 141:1385-1407. [PMID: 35089417 DOI: 10.1007/s00439-022-02430-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 01/04/2022] [Indexed: 12/29/2022]
Abstract
Coloboma, a congenital disorder characterized by gaps in ocular tissues, is caused when the choroid fissure fails to close during embryonic development. Several loci have been associated with coloboma, but these represent less than 40% of those that are involved with this disease. Here, we describe a novel coloboma-causing locus, BMP3. Whole exome sequencing and Sanger sequencing of patients with coloboma identified three variants in BMP3, two of which are predicted to be disease causing. Consistent with this, bmp3 mutant zebrafish have aberrant fissure closure. bmp3 is expressed in the ventral head mesenchyme and regulates phosphorylated Smad3 in a population of cells adjacent to the choroid fissure. Furthermore, mutations in bmp3 sensitize embryos to Smad3 inhibitor treatment resulting in open choroid fissures. Micro CT scans and Alcian blue staining of zebrafish demonstrate that mutations in bmp3 cause midface hypoplasia, suggesting that bmp3 regulates cranial neural crest cells. Consistent with this, we see active Smad3 in a population of periocular neural crest cells, and bmp3 mutant zebrafish have reduced neural crest cells in the choroid fissure. Taken together, these data suggest that Bmp3 controls Smad3 phosphorylation in neural crest cells to regulate early craniofacial and ocular development.
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Affiliation(s)
- Sabrina C Fox
- Department of Biological Sciences, University of Alberta, 11455 Saskatchewan Drive, Edmonton, AB, T6G 2E9, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, AB, Canada
| | - Sonya A Widen
- Department of Biological Sciences, University of Alberta, 11455 Saskatchewan Drive, Edmonton, AB, T6G 2E9, Canada.,Vienna BioCenter, Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria.,Women and Children's Health Research Institute, University of Alberta, Edmonton, AB, Canada
| | - Mika Asai-Coakwell
- Department of Animal and Poultry and Animal Science, University of Saskatchewan, Saskatoon, SK, Canada.,Department of Ophthalmology, University of Alberta, Edmonton, AB, Canada
| | - Serhiy Havrylov
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada.,Department of Ophthalmology, University of Alberta, Edmonton, AB, Canada
| | - Matthew Benson
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada.,Department of Ophthalmology, University of Alberta, Edmonton, AB, Canada
| | - Lisa B Prichard
- Department of Biological Sciences, MacEwan University, Edmonton, AB, Canada
| | - Pranidhi Baddam
- Department of Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Daniel Graf
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada.,Department of Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Ordan J Lehmann
- Women and Children's Health Research Institute, University of Alberta, Edmonton, AB, Canada.,Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada.,Department of Ophthalmology, University of Alberta, Edmonton, AB, Canada
| | - Andrew J Waskiewicz
- Department of Biological Sciences, University of Alberta, 11455 Saskatchewan Drive, Edmonton, AB, T6G 2E9, Canada. .,Women and Children's Health Research Institute, University of Alberta, Edmonton, AB, Canada.
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16
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Loss of αA or αB-Crystallin Accelerates Photoreceptor Cell Death in a Mouse Model of P23H Autosomal Dominant Retinitis Pigmentosa. Int J Mol Sci 2021; 23:ijms23010070. [PMID: 35008496 PMCID: PMC8744961 DOI: 10.3390/ijms23010070] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/17/2021] [Accepted: 12/20/2021] [Indexed: 02/08/2023] Open
Abstract
Inherited retinal degenerations (IRD) are a leading cause of visual impairment and can result from mutations in any one of a multitude of genes. Mutations in the light-sensing protein rhodopsin (RHO) is a leading cause of IRD with the most common of those being a missense mutation that results in substitution of proline-23 with histidine. This variant, also known as P23H-RHO, results in rhodopsin misfolding, initiation of endoplasmic reticulum stress, the unfolded protein response, and activation of cell death pathways. In this study, we investigate the effect of α-crystallins on photoreceptor survival in a mouse model of IRD secondary to P23H-RHO. We find that knockout of either αA- or αB-crystallin results in increased intraretinal inflammation, activation of apoptosis and necroptosis, and photoreceptor death. Our data suggest an important role for the ⍺-crystallins in regulating photoreceptor survival in the P23H-RHO mouse model of IRD.
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17
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Shiels A, Hejtmancik JF. Inherited cataracts: Genetic mechanisms and pathways new and old. Exp Eye Res 2021; 209:108662. [PMID: 34126080 PMCID: PMC8595562 DOI: 10.1016/j.exer.2021.108662] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/13/2021] [Accepted: 06/01/2021] [Indexed: 12/15/2022]
Abstract
Cataract(s) is the clinical equivalent of lens opacity and is caused by light scattering either by high molecular weight protein aggregates in lens cells or disruption of the lens microarchitecture itself. Genetic mutations underlying inherited cataract can provide insight into the biological processes and pathways critical for lens homeostasis and transparency, classically including the lens crystallins, connexins, membrane proteins or components, and intermediate filament proteins. More recently, cataract genes have been expanded to include newly identified biological processes such as chaperone or protein degradation components, transcription or growth factors, channels active in the lens circulation, and collagen and extracellular matrix components. Cataracts can be classified by age, and in general congenital cataracts are caused by severe mutations resulting in major damage to lens proteins, while age related cataracts are associated with variants that merely destabilize proteins thereby increasing susceptibility to environmental insults over time. Thus there might be separate pathways to opacity for congenital and age-related cataracts whereby congenital cataracts induce the unfolded protein response (UPR) and apoptosis to destroy the lens microarchitecture, while in age related cataract high molecular weight (HMW) aggregates formed by denatured crystallins bound by α-crystallin result in light scattering without severe damage to the lens microarchitecture.
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Affiliation(s)
- Alan Shiels
- Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, 63110, USA.
| | - J Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892-1860, USA.
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18
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Nath M, Shan Y, Myers AM, Fort PE. HspB4/αA-Crystallin Modulates Neuroinflammation in the Retina via the Stress-Specific Inflammatory Pathways. J Clin Med 2021; 10:jcm10112384. [PMID: 34071438 PMCID: PMC8198646 DOI: 10.3390/jcm10112384] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 05/14/2021] [Accepted: 05/24/2021] [Indexed: 01/28/2023] Open
Abstract
PURPOSE We have previously demonstrated that HspB4/αA-crystallin, a molecular chaperone, plays an important intrinsic neuroprotective role during diabetes, by its phosphorylation on residue 148. We also reported that HspB4/αA-crystallin is highly expressed by glial cells. There is a growing interest in the potential causative role of low-grade inflammation in diabetic retinopathy pathophysiology and retinal Müller glial cells' (MGCs') participation in the inflammatory response. MGCs indeed play a central role in retinal homeostasis via secreting various cytokines and other mediators. Hence, this study was carried out to delineate and understand the regulatory function of HspB4/αA-crystallin in the inflammatory response associated with metabolic stresses. METHODS Primary MGCs were isolated from knockout HspB4/αA-crystallin mice. These primary cells were then transfected with plasmids encoding either wild-type (WT), phosphomimetic (T148D), or non-phosphorylatable mutants (T148A) of HspB4/αA-crystallin. The cells were exposed to multiple metabolic stresses including serum starvation (SS) or high glucose with TNF-alpha (HG + T) before being further evaluated for the expression of inflammatory markers by qPCR. The total protein expression along with subcellular localization of NF-kB and the NLRP3 component was assessed by Western blot. RESULTS Elevated levels of IL-6, IL-1β, MCP-1, and IL-18 in SS were significantly diminished in MGCs overexpressing WT and further in T148D as compared to EV. The HG + T-induced increase in these inflammatory markers was also dampened by WT and even more significantly by T148D overexpression, whereas T148A was ineffective in either stress. Further analysis revealed that overexpression of WT or the T148D, also led to a significant reduction of Nlrp3, Asc, and caspase-1 transcript expression in serum-deprived MGCs and nearly abolished the NF-kB induction in HG + T diabetes-like stress. This mechanistic effect was further evaluated at the protein level and confirmed the stress-dependent regulation of NLRP3 and NF-kB by αA-crystallin. CONCLUSIONS The data gathered in this study demonstrate the central regulatory role of HspB4/αA-crystallin and its modulation by phosphorylation on T148 in retinal MGCs. For the first time, this study demonstrates that HspB4/αA-crystallin can dampen the stress-induced expression of pro-inflammatory cytokines through the modulation of multiple key inflammatory pathways, therefore, suggesting its potential as a therapeutic target for the modulation of chronic neuroinflammation.
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Affiliation(s)
- Madhu Nath
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA; (M.N.); (Y.S.); (A.M.M.)
| | - Yang Shan
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA; (M.N.); (Y.S.); (A.M.M.)
| | - Angela M. Myers
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA; (M.N.); (Y.S.); (A.M.M.)
| | - Patrice Elie Fort
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA; (M.N.); (Y.S.); (A.M.M.)
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48105, USA
- Correspondence:
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19
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Clinical characteristics of congenital lamellar cataract and myopia in a Chinese family. Biosci Rep 2021; 40:222026. [PMID: 32010934 PMCID: PMC7024846 DOI: 10.1042/bsr20191349] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 01/03/2020] [Accepted: 01/20/2020] [Indexed: 11/24/2022] Open
Abstract
To investigate the clinical characteristics and the genetic defect in a Chinese family with congenital lamellar cataract with myopia. Three generations of a single family were recruited in the present study. A detailed family history and clinical data were recorded. A total of 100 unrelated ethnically matched controls without family history of congenital cataracts and myopia were also recruited. Genomic DNA was extracted from peripheral blood leukocytes. The sequencing of candidate genes was performed to screen out the disease-causing mutation. The effects of amino acid changes on the structure of proteins were predicted by bioinformatics analysis. Affected individuals presented lamellar lens opacities and myopia. Direct sequencing revealed a heterozygous c. 34 C>T variation in the αA-crystallin protein (CRYAA) gene, which resulted in the replacement of a highly conserved arginine by cystine at codon 12 (p.R12C). This mutation co-segregated with all affected individuals and was not observed in unaffected members or the 100 normal controls. Bioinformatic analysis showed that a highly conserved region was located around Arg12, an increase in local hydrophobicity was shown around the substitution site and the secondary structure of the mutant CRYAA protein has been changed. This is the case of a congenital lamellar cataract phenotype with myopia associated with the mutation of Arg12Cys (p.R12C) in CRYAA. Our finding confirms the high rate of mutations at this dinucleotide. In addition, these results demonstrate a myopia susceptibility locus in this region, which might also be associated with the mutation in CRYAA.
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20
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Harding P, Cunha DL, Moosajee M. Animal and cellular models of microphthalmia. THERAPEUTIC ADVANCES IN RARE DISEASE 2021; 2:2633004021997447. [PMID: 37181112 PMCID: PMC10032472 DOI: 10.1177/2633004021997447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 02/02/2021] [Indexed: 05/16/2023]
Abstract
Microphthalmia is a rare developmental eye disorder affecting 1 in 7000 births. It is defined as a small (axial length ⩾2 standard deviations below the age-adjusted mean) underdeveloped eye, caused by disruption of ocular development through genetic or environmental factors in the first trimester of pregnancy. Clinical phenotypic heterogeneity exists amongst patients with varying levels of severity, and associated ocular and systemic features. Up to 11% of blind children are reported to have microphthalmia, yet currently no treatments are available. By identifying the aetiology of microphthalmia and understanding how the mechanisms of eye development are disrupted, we can gain a better understanding of the pathogenesis. Animal models, mainly mouse, zebrafish and Xenopus, have provided extensive information on the genetic regulation of oculogenesis, and how perturbation of these pathways leads to microphthalmia. However, differences exist between species, hence cellular models, such as patient-derived induced pluripotent stem cell (iPSC) optic vesicles, are now being used to provide greater insights into the human disease process. Progress in 3D cellular modelling techniques has enhanced the ability of researchers to study interactions of different cell types during eye development. Through improved molecular knowledge of microphthalmia, preventative or postnatal therapies may be developed, together with establishing genotype-phenotype correlations in order to provide patients with the appropriate prognosis, multidisciplinary care and informed genetic counselling. This review summarises some key discoveries from animal and cellular models of microphthalmia and discusses how innovative new models can be used to further our understanding in the future. Plain language summary Animal and Cellular Models of the Eye Disorder, Microphthalmia (Small Eye) Microphthalmia, meaning a small, underdeveloped eye, is a rare disorder that children are born with. Genetic changes or variations in the environment during the first 3 months of pregnancy can disrupt early development of the eye, resulting in microphthalmia. Up to 11% of blind children have microphthalmia, yet currently no treatments are available. By understanding the genes necessary for eye development, we can determine how disruption by genetic changes or environmental factors can cause this condition. This helps us understand why microphthalmia occurs, and ensure patients are provided with the appropriate clinical care and genetic counselling advice. Additionally, by understanding the causes of microphthalmia, researchers can develop treatments to prevent or reduce the severity of this condition. Animal models, particularly mice, zebrafish and frogs, which can also develop small eyes due to the same genetic/environmental changes, have helped us understand the genes which are important for eye development and can cause birth eye defects when disrupted. Studying a patient's own cells grown in the laboratory can further help researchers understand how changes in genes affect their function. Both animal and cellular models can be used to develop and test new drugs, which could provide treatment options for patients living with microphthalmia. This review summarises the key discoveries from animal and cellular models of microphthalmia and discusses how innovative new models can be used to further our understanding in the future.
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Affiliation(s)
| | | | - Mariya Moosajee
- UCL Institute of Ophthalmology, 11-43 Bath
Street, London, EC1V 9EL, UK
- Moorfields Eye Hospital NHS Foundation Trust,
London, UK
- Great Ormond Street Hospital for Children NHS
Foundation Trust, London, UK
- The Francis Crick Institute, London, UK
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21
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Grosas AB, Rekas A, Mata JP, Thorn DC, Carver JA. The Aggregation of αB-Crystallin under Crowding Conditions Is Prevented by αA-Crystallin: Implications for α-Crystallin Stability and Lens Transparency. J Mol Biol 2020; 432:5593-5613. [PMID: 32827531 DOI: 10.1016/j.jmb.2020.08.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 08/13/2020] [Accepted: 08/13/2020] [Indexed: 02/08/2023]
Abstract
One of the most crowded biological environments is the eye lens which contains a high concentration of crystallin proteins. The molecular chaperones αB-crystallin (αBc) with its lens partner αA-crystallin (αAc) prevent deleterious crystallin aggregation and cataract formation. However, some forms of cataract are associated with structural alteration and dysfunction of αBc. While many studies have investigated the structure and function of αBc under dilute in vitro conditions, the effect of crowding on these aspects is not well understood despite its in vivo relevance. The structure and chaperone ability of αBc under conditions that mimic the crowded lens environment were investigated using the polysaccharide Ficoll 400 and bovine γ-crystallin as crowding agents and a variety of biophysical methods, principally contrast variation small-angle neutron scattering. Under crowding conditions, αBc unfolds, increases its size/oligomeric state, decreases its thermal stability and chaperone ability, and forms kinetically distinct amorphous and fibrillar aggregates. However, the presence of αAc stabilizes αBc against aggregation. These observations provide a rationale, at the molecular level, for the aggregation of αBc in the crowded lens, a process that exhibits structural and functional similarities to the aggregation of cataract-associated αBc mutants R120G and D109A under dilute conditions. Strategies that maintain or restore αBc stability, as αAc does, may provide therapeutic avenues for the treatment of cataract.
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Affiliation(s)
- Aidan B Grosas
- Research School of Chemistry, The Australian National University, Canberra, ACT, 2601, Australia
| | - Agata Rekas
- National Deuteration Facility, Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234, Australia
| | - Jitendra P Mata
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234, Australia
| | - David C Thorn
- Research School of Chemistry, The Australian National University, Canberra, ACT, 2601, Australia
| | - John A Carver
- Research School of Chemistry, The Australian National University, Canberra, ACT, 2601, Australia.
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22
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Abstract
In vivo, small heat-shock proteins (sHsps) are key players in maintaining a healthy proteome. αB-crystallin (αB-c) or HspB5 is one of the most widespread and populous of the ten human sHsps. Intracellularly, αB-c acts via its molecular chaperone action as the first line of defence in preventing target protein unfolding and aggregation under conditions of cellular stress. In this review, we explore how the structure of αB-c confers its function and interactions within its oligomeric self, with other sHsps, and with aggregation-prone target proteins. Firstly, the interaction between the two highly conserved regions of αB-c, the central α-crystallin domain and the C-terminal IXI motif and how this regulates αB-c chaperone activity are explored. Secondly, subunit exchange is rationalised as an integral structural and functional feature of αB-c. Thirdly, it is argued that monomeric αB-c may be its most chaperone-species active, but at the cost of increased hydrophobicity and instability. Fourthly, the reasons why hetero-oligomerisation of αB-c with other sHsps is important in regulating cellular proteostasis are examined. Finally, the interaction of αB-c with aggregation-prone, partially folded target proteins is discussed. Overall, this paper highlights the remarkably diverse capabilities of αB-c as a caretaker of the cell.
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Affiliation(s)
- Junna Hayashi
- Research School of Chemistry, The Australian National University, Acton, ACT, 2601, Australia
| | - John A Carver
- Research School of Chemistry, The Australian National University, Acton, ACT, 2601, Australia.
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Interplay between Oxidative Stress, Inflammation, and Amyloidosis in the Anterior Segment of the Eye; Its Pathological Implications. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:6286105. [PMID: 32566091 PMCID: PMC7291327 DOI: 10.1155/2020/6286105] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 05/02/2020] [Accepted: 05/11/2020] [Indexed: 12/11/2022]
Abstract
There are different pathologies associated with amyloidogenic processes caused by the increase of reactive oxygen species (ROS) and the overactivation of inflammatory responses. These alterations are present in different regions of the anterior segment of the eye, and they have been associated with the development and progression of ocular pathologies, such as glaucoma, dry eye syndrome, keratitis, and cataracts among other pathologies. Aim. To discuss briefly the anatomical characteristics of the anterior segment of the eye and describe the interaction between oxidative stress (OS) and inflammatory responses, emphasizing the misfolding of several proteins leading to amyloidogenic processes occurring in the anterior segment and their implications in the development of ocular diseases. We performed a search on PubMed, CINAHL, and Embase using the MeSH terms “eye,” “anterior segment”, “inflammation”, “oxidative stress”, and “amyloidosis”. The search encompassed manuscripts published up to April 2019. A hundred forty-four published studies met the inclusion criteria. We present the current knowledge regarding the interaction between OS and the activation of inflammatory processes and how both can cause conformational changes in several peptides and proteins in each compartment of the anterior segment. However, we found that there is no consensus about which factor is the first to cause amyloidosis. Our conclusions suggest that there is an interplay among these factors forming a vicious cycle that leads to the loss of protein structure in ocular pathologies, and multifactorial therapies should be developed to avoid protein misfolding and to stop the progression of ocular pathologies.
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24
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Selivanova OM, Galzitskaya OV. Structural and Functional Peculiarities of α-Crystallin. BIOLOGY 2020; 9:biology9040085. [PMID: 32340218 PMCID: PMC7235859 DOI: 10.3390/biology9040085] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 04/03/2020] [Accepted: 04/15/2020] [Indexed: 12/23/2022]
Abstract
α-Crystallin is the major protein of the eye lens and a member of the family of small heat-shock proteins. Its concentration in the human eye lens is extremely high (about 450 mg/mL). Three-dimensional structure of native α-crystallin is unknown. First of all, this is the result of the highly heterogeneous nature of α-crystallin, which hampers obtaining it in a crystalline form. The modeling based on the electron microscopy (EM) analysis of α-crystallin preparations shows that the main population of the α-crystallin polydisperse complex is represented by oligomeric particles of rounded, slightly ellipsoidal shape with the diameter of about 13.5 nm. These complexes have molecular mass of about 700 kDa. In our opinion, the heterogeneity of the α-crystallin complex makes it impossible to obtain a reliable 3D model. In the literature, there is evidence of an enhanced chaperone function of α-crystallin during its dissociation into smaller components. This may indirectly indicate that the formation of heterogeneous complexes is probably necessary to preserve α-crystallin in a state inactive before stressful conditions. Then, not only the heterogeneity of the α-crystallin complex is an evolutionary adaptation that protects α-crystallin from crystallization but also the enhancement of the function of α-crystallin during its dissociation is also an evolutionary acquisition. An analysis of the literature on the study of α-crystallin in vitro led us to the assumption that, of the two α-crystallin isoforms (αA- and αB-crystallins), it is αA-crystallin that plays the role of a special chaperone for αB-crystallin. In addition, our data on X-ray diffraction analysis of α-crystallin at the sample concentration of about 170-190 mg/mL allowed us to assume that, at a high concentration, the eye lens α-crystallin can be in a gel-like stage. Finally, we conclude that, since all the accumulated data on structural-functional studies of α-crystallin were carried out under conditions far from native, they cannot adequately reflect the features of the functioning of α-crystallin in vivo.
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Affiliation(s)
- Olga M. Selivanova
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia;
| | - Oxana V. Galzitskaya
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia;
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia
- Correspondence: ; Tel.: +7-903-675-0156
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25
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Fujino M, Tagami A, Ojima M, Mizuno S, Abdellatif AM, Kuno A, Takahashi S. c-MAF deletion in adult C57BL/6J mice induces cataract formation and abnormal differentiation of lens fiber cells. Exp Anim 2020; 69:242-249. [PMID: 31969519 PMCID: PMC7220708 DOI: 10.1538/expanim.19-0137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The transcription factor c-MAF is a member of the large MAF family, members of which possess transactivation and bZIP domains. c-MAF plays an important role in lens formation, T-lymphocyte differentiation, hypertrophic chondrocyte differentiation, and kidney development in mouse embryos. However, because homozygous deletion of c-Maf in C57BL/6J mice causes embryonic lethality, the functions of c-MAF in adult mice remain largely uninvestigated. To address this issue, we generated c-Maf floxed (c-Maffl/fl) C57BL/6J mice and established tamoxifen-inducible c-Maf knockout mice (c-Maffl/fl; CAG-Cre-ERTM mice, c-MafΔTAM). After tamoxifen injection, adult c-MafΔTAM mice showed successful deletion of c-Maf protein and developed severe cataracts; cataracts are also seen in human patients who have mutations in the c-MAF DNA binding domain. Furthermore, adult c-MafΔTAM mice exhibited abnormal lens structure and impaired differentiation of lens fiber cells. In summary, we established c-Maffl/fl and c-MafΔTAM C57BL/6J mice, which can be useful animal models for the investigation of c-MAF function in various developmental stages and can also be used as a disease model for cataracts.
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Affiliation(s)
- Mitsunori Fujino
- Department of Anatomy and Embryology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.,Ph.D. Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Asuka Tagami
- Department of Anatomy and Embryology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Masami Ojima
- Laboratory Animal Resource Center (LARC), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Seiya Mizuno
- Laboratory Animal Resource Center (LARC), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Ahmed M Abdellatif
- Department of Anatomy and Embryology, Faculty of Veterinary Medicine, Mansoura University, Mansoura 35516, Egypt
| | - Akihiro Kuno
- Department of Anatomy and Embryology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Satoru Takahashi
- Department of Anatomy and Embryology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.,Laboratory Animal Resource Center (LARC), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.,Life Science Center, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.,International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.,Transborder Medical Research Center, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
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26
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Abstract
Cataract, the clinical correlate of opacity or light scattering in the eye lens, is usually caused by the presence of high-molecular-weight (HMW) protein aggregates or disruption of the lens microarchitecture. In general, genes involved in inherited cataracts reflect important processes and pathways in the lens including lens crystallins, connexins, growth factors, membrane proteins, intermediate filament proteins, and chaperones. Usually, mutations causing severe damage to proteins cause congenital cataracts, while milder variants increasing susceptibility to environmental insults are associated with age-related cataracts. These may have different pathogenic mechanisms: Congenital cataracts induce the unfolded protein response and apoptosis. By contrast, denatured crystallins in age-related cataracts are bound by α-crystallin and form light-scattering HMW aggregates. New therapeutic approaches to age-related cataracts use chemical chaperones to solubilize HMW aggregates, while attempts are being made to regenerate lenses using endogenous stem cells to treat congenital cataracts.
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Affiliation(s)
- Alan Shiels
- Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri 63110, USA;
| | - J Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892-1860, USA;
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27
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Why does the zebrafish cloche mutant develop lens cataract? PLoS One 2019; 14:e0211399. [PMID: 30861003 PMCID: PMC6413905 DOI: 10.1371/journal.pone.0211399] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 02/05/2019] [Indexed: 01/01/2023] Open
Abstract
The zebrafish has become a valuable model for examining ocular lens development, physiology and disease. The zebrafish cloche mutant, first described for its loss of hematopoiesis, also shows reduced eye and lens size, interruption in lens cell differentiation and a cataract likely caused by abnormal protein aggregation. To facilitate the use of the cloche mutant for studies on cataract development and prevention we characterized variation in the lens phenotype, quantified changes in gene expression by qRT-PCR and RNA-Seq and compared the ability of two promoters to drive expression of introduced proteins into the cloche lens. We found that the severity of cloche embryo lens cataract varied, while the decrease in lens diameter and retention of nuclei in differentiating lens fiber cells was constant. We found very low expression of both αB-crystallin genes (cryaba and cryabb) at 4 days post fertilization (dpf) by both qRT-PCR and RNA-Seq in cloche, cloche sibling and wildtype embryos and no significant difference in αA-crystallin (cryaa) expression. RNA-Seq analysis of 4 dpf embryos identified transcripts from 25,281 genes, with 1,329 showing statistically significantly different expression between cloche and wildtype samples. Downregulation of eight lens β- and γM-crystallin genes and 22 retinal related genes may reflect a general reduction in eye development and growth. Six stress response genes were upregulated. We did not find misregulation of any known components of lens development gene regulatory networks. These results suggest that the cloche lens cataract is not caused by loss of αA-crystallin or changes to lens gene regulatory networks. Instead, we propose that the cataract results from general physiological stress related to loss of hematopoiesis. Our finding that the zebrafish αA-crystallin promoter drove strong GFP expression in the cloche lens demonstrates its use as a tool for examining the effects of introduced proteins on lens crystallin aggregation and cataract prevention.
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28
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Dahiya V, Buchner J. Functional principles and regulation of molecular chaperones. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2018; 114:1-60. [PMID: 30635079 DOI: 10.1016/bs.apcsb.2018.10.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
To be able to perform their biological function, a protein needs to be correctly folded into its three dimensional structure. The protein folding process is spontaneous and does not require the input of energy. However, in the crowded cellular environment where there is high risk of inter-molecular interactions that may lead to protein molecules sticking to each other, hence forming aggregates, protein folding is assisted. Cells have evolved robust machinery called molecular chaperones to deal with the protein folding problem and to maintain proteins in their functional state. Molecular chaperones promote efficient folding of newly synthesized proteins, prevent their aggregation and ensure protein homeostasis in cells. There are different classes of molecular chaperones functioning in a complex interplay. In this review, we discuss the principal characteristics of different classes of molecular chaperones, their structure-function relationships, their mode of regulation and their involvement in human disorders.
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Affiliation(s)
- Vinay Dahiya
- Center for Integrated Protein Science Munich CIPSM at the Department Chemie, Technische Universität München, Garching, Germany
| | - Johannes Buchner
- Center for Integrated Protein Science Munich CIPSM at the Department Chemie, Technische Universität München, Garching, Germany.
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29
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RETRACTED: Peptide-induced formation of protein aggregates and amyloid fibrils in human and guinea pig αA-crystallins under physiological conditions of temperature and pH. Exp Eye Res 2018; 179:193-205. [PMID: 30448341 DOI: 10.1016/j.exer.2018.11.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 10/17/2018] [Accepted: 11/14/2018] [Indexed: 02/07/2023]
Abstract
This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal).
This article has been retracted at the request of the authors. The senior author contacted the journal in a forthright manner, in an effort to preserve the scientific integrity of the literature, after discovering a significant error in the results reported in the article. The authors were recently made aware of a paper by Kim et al. (Nature Commun. 2019) which shows a spirosome structure (the enzyme aldehyde-alcohol dehydrogenase) present in E. coli (Fig. 5a) that is very similar to the structure the authors thought formed when synthetic alpha A crystallin (66-80) peptide was incubated for 24 h with recombinant guinea pig alpha A insert crystallin (see Kumarasamy et al., Figs. 7C and F, and Fig. 9). Subsequent to publication of their report, the authors later found a number of images that showed what appeared to be the same structure present in samples of their presumably purified recombinant guinea pig alpha A insert crystallin which had been incubated without peptide for 24 h. Hence, the authors now conclude that the structures shown in Figs. 7C and F, and Fig. 9 of their article published in this journal are actually due to E. coli contaminant aldehyde-alcohol dehydrogenase. The authors deeply regret this error and any inconvenience it may have caused.
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30
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Zhang Y, Wang Z, Zhao G, Liu JX. Silver nanoparticles affect lens rather than retina development in zebrafish embryos. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 163:279-288. [PMID: 30056342 DOI: 10.1016/j.ecoenv.2018.07.079] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 07/17/2018] [Accepted: 07/20/2018] [Indexed: 06/08/2023]
Abstract
Silver nanoparticles (AgNPs) have been reported to inhibit specification and differentiation of erythroid cells, chromatophores, and myofibrils during zebrafish embryogenesis. However, the knowledge of biological effects of AgNPs on eye development, especially on lens development is scarce. In this study, embryos were exposed to or injected with 0.4 mg/L AgNPs, and the results indicate that no obvious morphological changes in eye formation were observed in the stressed embryos compared to the controls. However, clefts and vacuoles were observed in lens of embryos from AgNPs stressed group. Additionally, the down-regulated expressions of different lens crystallin isoform genes and the normal expression of retinal genes were observed in AgNPs stressed embryos, suggesting AgNPs might inhibit the development of lens rather than the development of retina in zebrafish embryos. Moreover, no obvious cell apoptosis was observed, but normal nuclear DNA and RNA export was observed in lens cells. Together, the data in this study reveal that AgNPs damage the development of lens rather than retina resulting in eye abnormalities via some unknown mechanisms rather than via triggering cells apoptosis or blocking nuclear DNA or RNA export.
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Affiliation(s)
- YanJun Zhang
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China.
| | - ZiYang Wang
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China.
| | - Guang Zhao
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China.
| | - Jing-Xia Liu
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China; Collaborative Innovation Center for Efficient and Health Production of Fisheries in Hunan Province, Changde 415000, Hunan, China.
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31
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Song Z, Si N, Xiao W. A novel mutation in the CRYAA gene associated with congenital cataract and microphthalmia in a Chinese family. BMC MEDICAL GENETICS 2018; 19:190. [PMID: 30340470 PMCID: PMC6194747 DOI: 10.1186/s12881-018-0695-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 09/24/2018] [Indexed: 11/10/2022]
Abstract
Background Congenital cataract is the leading cause of blindness in children worldwide. Approximately half of all congenital cataracts have a genetic basis. Protein aggregation is the single most important factor in cataract formation. Methods A four-generation Chinese family diagnosed with autosomal dominant congenital cataracts and microphthalmia was recruited at the Shengjing Hospital of China Medical University. Genomic DNA was extracted from the peripheral blood of the participants. All coding exons and flanking regions of seven candidate genes (CRYAA, CRYBA4, CRYBB2, CRYGC, GJA8, MAF, and PITX3) were amplified and sequenced. Restriction fragment length polymorphism (RFLP) assays were performed to confirm the candidate causative variant, c.35G > T in the CRYAA gene. We constructed pcDNA3.1(+)-CRYAA expression plasmids containing either the wild-type or the R12L mutant alleles and respectively transfected them into HEK293T cells and into HeLa cells. Western blotting was performed to determine protein expression levels and protein solubility. Immunofluorescence was performed to determine protein sub-cellular localization. Results A heterozygous variant c.35G > T was identified in exon 1 of CRYAA, which resulted in a substitution of arginine to leucine at codon 12 (p.R12L). The nucleotide substitution c.35G > T was co-segregated with the disease phenotype in the family. The mutant R12L-CRYAA in HEK293T cells showed a significant increase in the expression level of the CRYAA protein compared with the wild-type cells. Moreover, a large amount of the mutant protein aggregated in the precipitate where the wild-type protein was not detected. Immunofluorescence studies showed that the overexpressed mutant CRYAA in HeLa cells formed large cytoplasmic aggregates and aggresomes. Conclusions In summary, we described a case of human congenital cataract and microphthalmia caused by a novel mutation in the CRYAA gene, which substituted an arginine at position 12 in the N-terminal region of αA-crystallin. The molecular mechanisms that underlie the pathogenesis of human congenital cataract may be characterized by the prominent effects of the p.R12L mutation on αA-crystallin aggregation and solubility. Our study also expands the spectrum of known CRYAA mutations.
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Affiliation(s)
- Zixun Song
- Department of Ophthalmology, Shengjing Hospital, China Medical University, Shenyang, 110004, Liaoning, China
| | - Nuo Si
- McKusick-Zhang Center for Genetic Medicine, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing, 100005, China
| | - Wei Xiao
- Department of Ophthalmology, Shengjing Hospital, China Medical University, Shenyang, 110004, Liaoning, China.
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32
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Kourtis N, Tavernarakis N. Small heat shock proteins and neurodegeneration: recent developments. Biomol Concepts 2018; 9:94-102. [PMID: 30133417 DOI: 10.1515/bmc-2018-0009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 06/25/2018] [Indexed: 12/12/2022] Open
Abstract
AbstractMembers of the small heat shock protein (sHSP) family are molecular chaperones with a critical role in the maintenance of cellular homeostasis under unfavorable conditions. The chaperone properties of sHSPs prevent protein aggregation, and sHSP deregulation underlies the pathology of several diseases, including neurodegenerative disorders. Recent evidence suggests that the clientele of sHSPs is broad, and the mechanisms of sHSP-mediated neuroprotection diverse. Nonetheless, the crosstalk of sHSPs with the neurodegeneration-promoting signaling pathways remains poorly understood. Here, we survey recent findings on the role and regulation of sHSPs in neurodegenerative diseases.
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Affiliation(s)
- Nikos Kourtis
- Department of Pathology and Laura and Isaac Perlmutter Cancer Center, NYU School of Medicine, New York, NY 10016, USA
| | - Nektarios Tavernarakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Heraklion, 70013, Crete, Greece.,Department of Basic Sciences, Faculty of Medicine, University of Crete, Heraklion, 71003, Crete, Greece
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33
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Pumputis PG, Dayeh VR, Lee LEJ, Pham PH, Liu Z, Viththiyapaskaran S, Bols NC. Responses of rainbow trout intestinal epithelial cells to different kinds of nutritional deprivation. FISH PHYSIOLOGY AND BIOCHEMISTRY 2018; 44:1197-1214. [PMID: 29754319 DOI: 10.1007/s10695-018-0511-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 05/04/2018] [Indexed: 06/08/2023]
Abstract
In order to develop an in vitro system to study the cell biology of starvation in the fish intestine, rainbow trout intestinal epithelial cells were subjected to three kinds of nutrient deprivation and evaluated for 7 days. The RTgutGC cell line was grown into monolayers in Leibovitz's basal medium supplemented with fetal bovine serum (L15/FBS) and then subjected to deprivation of serum (L15); of serum, amino acids, and vitamin (L15/ex); and of all nutrients (L15/salts). After 7 days of nutrient deprivation, the cells remained attached to the plastic surface as monolayers but changes were seen in shape, with the cells becoming more polygonal, actin and α-tubulin cytoskeleton organization, and in tight junction protein-1 (ZO-1) localization. Two barrier functions, transepithelial electrical resistance (TEER) and Lucifer Yellow (LY) retention, were impaired by nutrient deprivation. In L15/FBS, cells rapidly healed a gap or wound in the monolayer. In L15 and L15/ex, some cells moved into the gap, but after 7 days, the wound remained unhealed, whereas in L15/salts, cells did not even migrate into the gap. Upon nutrient replenishment (L15/FBS) after 7 days in L15, L15/ex, or L15/salts, cells proliferated again and healed a wound. After 7 days of nutrient deprivation, monolayers were successfully passaged with trypsin and cells in L15/FBS grew to again form monolayers. Therefore, rainbow trout intestinal epithelial cells survived starvation, but barrier and wound healing functions were impaired.
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Affiliation(s)
- Patrick G Pumputis
- Department of Biology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
| | - Vivian R Dayeh
- Department of Biology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
| | - Lucy E J Lee
- Faculty of Science, University of the Fraser Valley, Abbotsford, BC, V2S 7M8, Canada
| | - Phuc H Pham
- Department of Biology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
| | - Zhenzhen Liu
- Department of Biology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
| | | | - Niels C Bols
- Department of Biology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
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34
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Li Y, Xu X, Qu R, Zhang G, Rajoka MSR, Shao D, Jiang C, Shi J. Heterologous expression of Oenococcus oeni sHSP20 confers temperature stress tolerance in Escherichia coli. Cell Stress Chaperones 2018; 23:653-662. [PMID: 29359265 PMCID: PMC6045537 DOI: 10.1007/s12192-018-0874-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 12/19/2017] [Accepted: 01/03/2018] [Indexed: 12/11/2022] Open
Abstract
Small heat shock proteins (sHSPs) are heat shock proteins sized 12-43 kDa that can protect proteins from denaturation, particularly under high temperature; sHSPs thus increase the heat tolerance capability of an organisms enabling survival in adverse climates. sHSP20 is overexpressed in Oenococcus oeni in response to low temperatures. However, we found that overexpression of sHSP20 in Escherichia coli BL21 increased the microbial survival ratio at 50 °C by almost 2 h. Adding sHSP20 to the glutamate dehydrogenase solution significantly increased the stability of the enzyme at high temperature (especially at 60-70 °C), low pH values (especially below 6.0), and high concentration of metal ions of Ga2+, Zn2+, Mn2+, and Fe3+. Notably, the coexpression of sHSP20 significantly enhanced soluble expression of laccase from Phomopsis sp. XP-8 (CCTCCM209291) in E. coli without codon optimization, as well as the activity and heat stability of the expressed enzyme. In addition to the chaperone activity of sHSP20 in the gene containing host in vivo and the enzyme heat stability in vitro, our study indicated the capability of coexpression of sHSP20 to increase the efficiency of prokaryotic expression of fungal genes and the activity of expressed enzymes. Graphical abstract ᅟ.
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Affiliation(s)
- Yan Li
- Key Laboratory for Space Bioscience and Space Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an, 710072 Shaanxi People’s Republic of China
| | - Xiaoguang Xu
- Key Laboratory for Space Bioscience and Space Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an, 710072 Shaanxi People’s Republic of China
| | - Rui Qu
- Key Laboratory for Space Bioscience and Space Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an, 710072 Shaanxi People’s Republic of China
| | - Guoqiang Zhang
- College of Food Science, Agricultural and Animal Husbandry College of Tibet University, Linzhi, 860000 Xi Zang People’s Republic of China
| | - Muhammad Shahid Riaz Rajoka
- Key Laboratory for Space Bioscience and Space Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an, 710072 Shaanxi People’s Republic of China
| | - Dongyan Shao
- Key Laboratory for Space Bioscience and Space Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an, 710072 Shaanxi People’s Republic of China
| | - Chunmei Jiang
- Key Laboratory for Space Bioscience and Space Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an, 710072 Shaanxi People’s Republic of China
| | - Junling Shi
- Key Laboratory for Space Bioscience and Space Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an, 710072 Shaanxi People’s Republic of China
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Ruebsam A, Dulle JE, Myers AM, Sakrikar D, Green KM, Khan NW, Schey K, Fort PE. A specific phosphorylation regulates the protective role of αA-crystallin in diabetes. JCI Insight 2018; 3:97919. [PMID: 29467334 DOI: 10.1172/jci.insight.97919] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 01/17/2018] [Indexed: 12/19/2022] Open
Abstract
Neurodegeneration is a central aspect of the early stages of diabetic retinopathy, the primary ocular complication associated with diabetes. While progress has been made to improve the vascular perturbations associated with diabetic retinopathy, there are still no treatment options to counteract the neuroretinal degeneration associated with diabetes. Our previous work suggested that the molecular chaperones α-crystallins could be involved in the pathophysiology of diabetic retinopathy; however, the role and regulation of α-crystallins remained unknown. In the present study, we demonstrated the neuroprotective role of αA-crystallin during diabetes and its regulation by its phosphorylation on residue 148. We further characterized the dual role of αA-crystallin in neurons and glia, its essential role for neuronal survival, and its direct dependence on phosphorylation on this residue. These findings support further evaluation of αA-crystallin as a treatment option to promote neuron survival in diabetic retinopathy and neurodegenerative diseases in general.
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Affiliation(s)
- Anne Ruebsam
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan, USA
| | - Jennifer E Dulle
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan, USA
| | - Angela M Myers
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan, USA
| | | | - Katelyn M Green
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan, USA
| | - Naheed W Khan
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan, USA
| | - Kevin Schey
- Department of Biochemistry and Ophthalmology and Visual Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Patrice E Fort
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan, USA.,Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
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Molecular Age-Related Changes in the Anterior Segment of the Eye. J Ophthalmol 2017; 2017:1295132. [PMID: 29147580 PMCID: PMC5632897 DOI: 10.1155/2017/1295132] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Revised: 07/09/2017] [Accepted: 08/30/2017] [Indexed: 12/11/2022] Open
Abstract
Purpose To examine the current knowledge about the age-related processes in the anterior segment of the eye at a biological, clinical, and molecular level. Methods We reviewed the available published literature that addresses the aging process of the anterior segment of the eye and its associated molecular and physiological events. We performed a search on PubMed, CINAHL, and Embase using the MeSH terms “eye,” “anterior segment,” and “age.” We generated searches to account for synonyms of these keywords and MESH headings as follows: (1) “Eye” AND “ageing process” OR “anterior segment ageing” and (2) “Anterior segment” AND “ageing process” OR “anterior segment” AND “molecular changes” AND “age.” Results. Among the principal causes of age-dependent alterations in the anterior segment of the eye, we found the mutation of the TGF-β gene and loss of autophagy in addition to oxidative stress, which contributes to the pathogenesis of degenerative diseases. Conclusions In this review, we summarize the current knowledge regarding some of the molecular mechanisms related to aging in the anterior segment of the eye. We also introduce and propose potential roles of autophagy, an important mechanism responsible for maintaining homeostasis and proteostasis under stress conditions in the anterior segment during aging.
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Transcriptome analysis of developing lens reveals abundance of novel transcripts and extensive splicing alterations. Sci Rep 2017; 7:11572. [PMID: 28912564 PMCID: PMC5599659 DOI: 10.1038/s41598-017-10615-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 08/11/2017] [Indexed: 01/22/2023] Open
Abstract
Lens development involves a complex and highly orchestrated regulatory program. Here, we investigate the transcriptomic alterations and splicing events during mouse lens formation using RNA-seq data from multiple developmental stages, and construct a molecular portrait of known and novel transcripts. We show that the extent of novelty of expressed transcripts decreases significantly in post-natal lens compared to embryonic stages. Characterization of novel transcripts into partially novel transcripts (PNTs) and completely novel transcripts (CNTs) (novelty score ≥ 70%) revealed that the PNTs are both highly conserved across vertebrates and highly expressed across multiple stages. Functional analysis of PNTs revealed their widespread role in lens developmental processes while hundreds of CNTs were found to be widely expressed and predicted to encode for proteins. We verified the expression of four CNTs across stages. Examination of splice isoforms revealed skipped exon and retained intron to be the most abundant alternative splicing events during lens development. We validated by RT-PCR and Sanger sequencing, the predicted splice isoforms of several genes Banf1, Cdk4, Cryaa, Eif4g2, Pax6, and Rbm5. Finally, we present a splicing browser Eye Splicer (http://www.iupui.edu/~sysbio/eye-splicer/), to facilitate exploration of developmentally altered splicing events and to improve understanding of post-transcriptional regulatory networks during mouse lens development.
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Functional non-coding polymorphism in an EPHA2 promoter PAX2 binding site modifies expression and alters the MAPK and AKT pathways. Sci Rep 2017; 7:9992. [PMID: 28855599 PMCID: PMC5577203 DOI: 10.1038/s41598-017-10117-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 08/04/2017] [Indexed: 01/11/2023] Open
Abstract
To identify possible genetic variants influencing expression of EPHA2 (Ephrin-receptor Type-A2), a tyrosine kinase receptor that has been shown to be important for lens development and to contribute to both congenital and age related cataract when mutated, the extended promoter region of EPHA2 was screened for variants. SNP rs6603883 lies in a PAX2 binding site in the EPHA2 promoter region. The C (minor) allele decreased EPHA2 transcriptional activity relative to the T allele by reducing the binding affinity of PAX2. Knockdown of PAX2 in human lens epithelial (HLE) cells decreased endogenous expression of EPHA2. Whole RNA sequencing showed that extracellular matrix (ECM), MAPK-AKT signaling pathways and cytoskeleton related genes were dysregulated in EPHA2 knockdown HLE cells. Taken together, these results indicate a functional non-coding SNP in EPHA2 promoter affects PAX2 binding and reduces EPHA2 expression. They further suggest that decreasing EPHA2 levels alters MAPK, AKT signaling pathways and ECM and cytoskeletal genes in lens cells that could contribute to cataract. These results demonstrate a direct role for PAX2 in EPHA2 expression and help delineate the role of EPHA2 in development and homeostasis required for lens transparency.
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Zhao Z, Fan Q, Zhou P, Ye H, Cai L, Lu Y. Association of alpha A-crystallin polymorphisms with susceptibility to nuclear age-related cataract in a Han Chinese population. BMC Ophthalmol 2017; 17:133. [PMID: 28755661 PMCID: PMC5534246 DOI: 10.1186/s12886-017-0529-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 07/21/2017] [Indexed: 01/01/2023] Open
Abstract
Background Alpha A-crystallin (CRYAA) is considered critical for the maintenance of lens transparency and is related to the pathogenesis of age-related cataracts (ARCs), especially the nuclear subtype. As the 5′ untranslated region (5′ UTR) modulates gene expression, the purpose of current study was to investigate whether single nucleotide polymorphisms (SNPs) in the 5′ UTR of CRYAA were associated with susceptibility to ARC in a Han Chinese population and to clarify the mechanism of this association. Methods SNPs in the 5′ UTR (−1 to −1000) of CRYAA were identified in 243 nuclear ARC patients and 263 controls using polymerase chain reaction and DNA sequencing. Allele and genotype frequencies were calculated and compared between two groups. Haploview 4.2 was used to calculate the linkage disequilibrium index, and the SHEsis analysis platform was used to infer haplotype construction. A dual-luciferase reporter gene assay was used for transcription of CRYAA in the presence of a protective haplotype with individual SNP alteration, Chromatin immunoprecipitation (ChIP) was employed to determine whether SNPs regulated CRYAA expression by altering the binding affinity of transcription factors. Results Three polymorphisms were identified in the 5′ UTR of CRYAA: rs3761381 (P = 0.000357, odds ratio [OR] = 1.837), rs13053109 (P = 0.788, OR = 1.086), and rs7278468 (P = 0.00136, OR = 0.652). The haplotype C-G-T (P = 0.0014, OR = 1.536) increased the risk of nuclear ARC, whereas the haplotype T-G-G (P = 0.00029, OR = 0.535) decreased the risk. The haplotype C-G-T decreased CRYAA transcription through rs7278468, which is located in the binding site of specificity protein 1 (Sp1). Furthermore, the G allele of rs7278468 increased CRYAA transcription by enhancing the binding affinity of Sp1. Conclusions These data indicate that the CRYAA polymorphism is a genetic marker of inter-individual differences in the risk of nuclear ARC. Electronic supplementary material The online version of this article (doi:10.1186/s12886-017-0529-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Zhennan Zhao
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, 83 Fenyang Road, Shanghai, 200031, People's Republic of China
| | - Qi Fan
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, 83 Fenyang Road, Shanghai, 200031, People's Republic of China
| | - Peng Zhou
- Department of Ophthalmology, Parkway Health Hong Qiao Medical Center, Shanghai, 200336, People's Republic of China
| | - HongFei Ye
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, 83 Fenyang Road, Shanghai, 200031, People's Republic of China
| | - Lei Cai
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, 83 Fenyang Road, Shanghai, 200031, People's Republic of China
| | - Yi Lu
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, 83 Fenyang Road, Shanghai, 200031, People's Republic of China.
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Lyon YA, Sabbah GM, Julian RR. Identification of Sequence Similarities among Isomerization Hotspots in Crystallin Proteins. J Proteome Res 2017; 16:1797-1805. [PMID: 28234481 PMCID: PMC5387677 DOI: 10.1021/acs.jproteome.7b00073] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The eye lens crystallins represent
an ideal target for studying
the effects of aging on protein structure. Herein we examine separately
the water-soluble (WS) and water-insoluble (WI) crystallin fractions
and identify sites of isomerization and epimerization. Both collision-induced
dissociation and radical-directed dissociation are needed for detection
of these non-mass-shifting post-translational modifications. Isomerization
levels differ significantly between the WS and the WI fractions from
sheep, pig, and cow eye lenses. Residues that are most susceptible
to isomerization are identified site-specifically and are found to
reside in structurally disordered regions. However, isomerization
in structured domains, although less common, often yields more dramatic
effects on solubility. Numerous isomerization hotspots were also identified
and occur in regions with aspartic acid and serine repeats. For example, 128KMEIVDDDVPSLW140 in βB3
crystallin contains three sequential aspartic acid residues and is
isomerized heavily in the WI fractions, while it is not modified at
all in the WS fractions. Potential causes for enhanced isomerization
at sites with acidic residue repeats are presented. The importance
of acidic residue repeats extends beyond the lens, as they are found
in many other long-lived proteins associated with disease.
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Affiliation(s)
- Yana A Lyon
- Department of Chemistry, University of California , Riverside, 501 Big Springs Road, Riverside, California 92521, United States
| | - Georgette M Sabbah
- Department of Chemistry, University of California , Riverside, 501 Big Springs Road, Riverside, California 92521, United States
| | - Ryan R Julian
- Department of Chemistry, University of California , Riverside, 501 Big Springs Road, Riverside, California 92521, United States
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Tikhomirova TS, Selivanova OM, Galzitskaya OV. α-Crystallins are small heat shock proteins: Functional and structural properties. BIOCHEMISTRY (MOSCOW) 2017; 82:106-121. [DOI: 10.1134/s0006297917020031] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
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42
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Cheng MH, Tam CN, Choy KW, Tsang WH, Tsang SL, Pang CP, Song YQ, Sham MH. A γA-Crystallin Mouse Mutant Secc with Small Eye, Cataract and Closed Eyelid. PLoS One 2016; 11:e0160691. [PMID: 27513760 PMCID: PMC4981419 DOI: 10.1371/journal.pone.0160691] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 07/23/2016] [Indexed: 11/18/2022] Open
Abstract
Cataract is the most common cause of visual loss in humans. A spontaneously occurred, autosomal dominant mouse mutant Secc, which displayed combined features of small eye, cataract and closed eyelid was discovered in our laboratory. In this study, we identified the mutation and characterized the cataract phenotype of this novel Secc mutant. The Secc mutant mice have eyelids that remain half-closed throughout their life. The mutant lens has a significant reduction in size and with opaque spots clustered in the centre. Histological analysis showed that in the core region of the mutant lens, the fiber cells were disorganized and clefts and vacuoles were observed. The cataract phenotype was evident from new born stage. We identified the Secc mutation by linkage analysis using whole genome microsatellite markers and SNP markers. The Secc locus was mapped at chromosome 1 flanked by SNPs rs3158129 and rs13475900. Based on the chromosomal position, the candidate cataract locus γ-crystallin gene cluster (Cryg) was investigated by sequencing. A single base deletion (299delG) in exon 3 of Cryga which led to a frame-shift of amino acid sequence from position 91 was identified. As a result of this mutation, the sequences of the 3rd and 4th Greek-key motifs of the γA-crystallin are replaced with an unrelated C-terminal peptide of 75 residues long. Coincidentally, the point mutation generated a HindIII restriction site, allowing the identification of the CrygaSecc mutant allele by RFLP. Western blot analysis of 3-week old lenses showed that the expression of γ-crystallins was reduced in the CrygaSecc mutant. Furthermore, in cell transfection assays using CrygaSecc mutant cDNA expression constructs in 293T, COS-7 and human lens epithelial B3 cell lines, the mutant γA-crystallins were enriched in the insoluble fractions and appeared as insoluble aggregates in the transfected cells. In conclusion, we have demonstrated that the Secc mutation leads to the generation of CrygaSecc proteins with reduced solubility and prone to form aggregates within lens cells. Accumulation of mutant proteins in the lens fibers would lead to cataract formation in the Secc mutant.
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Affiliation(s)
- Man Hei Cheng
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Chung Nga Tam
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Kwong Wai Choy
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Hong Kong, China
| | - Wai Hung Tsang
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Sze Lan Tsang
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Chi Pui Pang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - You Qiang Song
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.,Centre for Reproduction Development and Growth, Li Ka Shing Faculty of Medicine, Pokfulam, Hong Kong SAR, China
| | - Mai Har Sham
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.,Centre for Reproduction Development and Growth, Li Ka Shing Faculty of Medicine, Pokfulam, Hong Kong SAR, China
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Differentiation of Induced Pluripotent Stem Cells to Lentoid Bodies Expressing a Lens Cell-Specific Fluorescent Reporter. PLoS One 2016; 11:e0157570. [PMID: 27322380 PMCID: PMC4913943 DOI: 10.1371/journal.pone.0157570] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 06/01/2016] [Indexed: 12/18/2022] Open
Abstract
Curative approaches for eye cataracts and other eye abnormalities, such as myopia and hyperopia currently suffer from a lack of appropriate models. Here, we present a new approach for in vitro growth of lentoid bodies from induced pluripotent stem (iPS) cells as a tool for ophthalmological research. We generated a transgenic mouse line with lens-specific expression of a fluorescent reporter driven by the alphaA crystallin promoter. Fetal fibroblasts were isolated from transgenic fetuses, reprogrammed to iPS cells, and differentiated to lentoid bodies exploiting the specific fluorescence of the lens cell-specific reporter. The employment of cell type-specific reporters for establishing and optimizing differentiation in vitro seems to be an efficient and generally applicable approach for developing differentiation protocols for desired cell populations.
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Babizhayev MA. Generation of reactive oxygen species in the anterior eye segment. Synergistic codrugs of N-acetylcarnosine lubricant eye drops and mitochondria-targeted antioxidant act as a powerful therapeutic platform for the treatment of cataracts and primary open-angle glaucoma. BBA CLINICAL 2016; 6:49-68. [PMID: 27413694 PMCID: PMC4925929 DOI: 10.1016/j.bbacli.2016.04.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 04/05/2016] [Accepted: 04/11/2016] [Indexed: 12/13/2022]
Abstract
Senile cataract is a clouding of the lens in the aging eye leading to a decrease in vision. Symptoms may include faded colors, blurry vision, halos around light, trouble with bright lights, and trouble seeing at night. This may result in trouble driving, reading, or recognizing faces. Cataracts are the cause of half of blindness and 33% of visual impairment worldwide. Cataracts result from the deposition of aggregated proteins in the eye lens and lens fiber cells plasma membrane damage which causes clouding of the lens, light scattering, and obstruction of vision. ROS induced damage in the lens cell may consist of oxidation of proteins, DNA damage and/or lipid peroxidation, all of which have been implicated in cataractogenesis. The inner eye pressure (also called intraocular pressure or IOP) rises because the correct amount of fluid can't drain out of the eye. With primary open-angle glaucoma, the entrances to the drainage canals are clear and should be working correctly. The clogging problem occurs further inside the drainage canals, similar to a clogged pipe below the drain in a sink. The excessive oxidative damage is a major factor of the ocular diseases because the mitochondrial respiratory chain in mitochondria of the vital cells is a significant source of the damaging reactive oxygen species superoxide and hydrogen peroxide. However, despite the clinical importance of mitochondrial oxidative damage, antioxidants have been of limited therapeutic success. This may be because the antioxidants are not selectively taken up by mitochondria, but instead are dispersed throughout the body, ocular tissues and fluids' moieties. This work is an attempt to integrate how mitochondrial reactive oxygen species (ROS) are altered in the aging eye, along with those protective and repair therapeutic systems believed to regulate ROS levels in ocular tissues and how damage to these systems contributes to age-onset eye disease and cataract formation. Mitochondria-targeted antioxidants might be used to effectively prevent ROS-induced oxidation of lipids and proteins in the inner mitochondrial membrane in vivo. The authors developed and patented the new ophthalmic compositions including N-acetylcarnosine acting as a prodrug of naturally targeted to mitochondria l-carnosine endowed with pluripotent antioxidant activities, combined with mitochondria-targeted rechargeable antioxidant (either MitoVit E, Mito Q or SkQs) as a potent medicine to treat ocular diseases. Such specificity is explained by the fact that developed compositions might be used to effectively prevent ROS-induced oxidation of lipids and proteins in the inner mitochondrial membrane in vivo and outside mitochondria in the cellular and tissue structures of the lens and eye compartments. Mitochondrial targeting of compounds with universal types of antioxidant activity represents a promising approach for treating a number of ROS-related ocular diseases of the aging eye and can be implicated in the management of cataracts and primary open-angle glaucoma.
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Affiliation(s)
- Mark A Babizhayev
- Innovative Vision Products, Inc., 3511 Silverside Road, Suite 105, County of New Castle, DE 19810, USA
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45
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Tjondro HC, Xi YB, Chen XJ, Su JT, Yan YB. Membrane insertion of αA-crystallin is oligomer-size dependent. Biochem Biophys Res Commun 2016; 473:1-7. [DOI: 10.1016/j.bbrc.2016.03.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 03/08/2016] [Indexed: 10/22/2022]
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46
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Ma X, Jiao X, Ma Z, Hejtmancik JF. Polymorphism rs7278468 is associated with Age-related cataract through decreasing transcriptional activity of the CRYAA promoter. Sci Rep 2016; 6:23206. [PMID: 26984531 PMCID: PMC4794711 DOI: 10.1038/srep23206] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 03/02/2016] [Indexed: 11/18/2022] Open
Abstract
CRYAA plays critical functional roles in lens transparency and opacity, and polymorphisms near CRYAA have been associated with age-related cataract (ARC). This study examines polymorphisms in the CRYAA promoter region for association with ARC and elucidates the mechanisms of this association. Three SNPs nominally associated with ARC were identified in the promoter region of CRYAA: rs3761382 (P = 0.06, OR (Odds ratio) = 1.5), rs13053109 (P = 0.04, OR = 1.6), rs7278468 (P = 0.007, OR = 0.6). The C-G-T haplotype increased the risk for ARC overall (P = 0.005, OR = 1.8), and both alleles and haplotypes show a stronger association with cortical cataract (rs3761382, P = 0.002, OR = 2.1; rs13053109, P = 0.002, OR = 2.1; rs7278468, P = 0.0007, OR = 0.5; C-G-T haplotype, P = 0.0003, OR = 2.2). The C-G-T risk haplotype decreased transcriptional activity through rs7278468, which lies in a consensus binding site for the transcription repressor KLF10. KLF10 binding inhibited CRYAA transcription, and both binding and inhibition were greater with the T rs7278468 allele. Knockdown of KLF10 in HLE cells partially rescued the transcriptional activity of CRYAA with rs7278468 T allele, but did not affect activity with the G allele. Thus, our data suggest that the T allele of rs7278468 in the CRYAA promoter is associated with ARC through increasing binding of KLF-10 and thus decreasing CRYAA transcription.
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Affiliation(s)
- Xiaoyin Ma
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, 325003, China.,Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Xiaodong Jiao
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Zhiwei Ma
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - J Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Takata T, Fujii N. Isomerization of Asp residues plays an important role in αA-crystallin dissociation. FEBS J 2016; 283:850-9. [PMID: 26700637 DOI: 10.1111/febs.13635] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 11/08/2015] [Accepted: 12/18/2015] [Indexed: 11/29/2022]
Abstract
Aged cataract formation is caused by the accumulative precipitation of lens proteins incorporating diverse post-translational modifications. α-Crystallin, a major structural and functional lens protein, consists of a large polymeric structure that is dissociated and insolubilized with accumulative post-translational modifications. One such modification, isomerization of Asp, was recently identified in αB-crystallin monomers derived from aged lens. However, the distributions of Asp isomers in each lens fraction remain unknown. Here, α-crystallin fractions from aged lens were separated into heteropolymeric and monomeric forms to determine the Asp isomerization ratios in each fraction. Lens of four different ages were homogenized and centrifuged, and the soluble fraction was applied to size-exclusion chromatography. The heteropolymeric α-crystallin and monomeric crystallin fractions were obtained and concentrated. After trypsin digestion, each fraction was independently applied to liquid chromatography equipped with mass spectrometry to extract α-crystallin-derived peptides containing Asp isomers. The results showed that Asp58, Asp84 and Asp151 of αA-crystallin were highly isomerized in the monomeric fraction, but not isomerized to the same level in the heteropolymeric fraction. Each type of Asp isomerization increased in an age-dependent manner, was site-specific and was similar to previous results from lens water-insoluble fractions. These results imply that isomerization of Asp residues leads to dissociation of αA-crystallin from the heteropolymeric state and induces insolubilization in aged lens. Taken together, our findings suggest that isomerization of Asp might disrupt the higher order polymeric state of α-crystallin, resulting in decreased solubility and function, ultimately contributing to lens protein impairment and cataract formation with aging.
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Affiliation(s)
- Takumi Takata
- Department of Biochemistry, Tokyo University of Pharmacy and Life Sciences, Japan
| | - Noriko Fujii
- Research Reactor Institute, Kyoto University, Osaka, Japan
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48
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49
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Koteiche HA, Claxton DP, Mishra S, Stein RA, McDonald ET, Mchaourab HS. Species-Specific Structural and Functional Divergence of α-Crystallins: Zebrafish αBa- and Rodent αA(ins)-Crystallin Encode Activated Chaperones. Biochemistry 2015; 54:5949-58. [PMID: 26378715 DOI: 10.1021/acs.biochem.5b00678] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In addition to contributing to lens optical properties, the α-crystallins are small heat shock proteins that possess chaperone activity and are predicted to bind and sequester destabilized proteins to delay cataract formation. The current model of α-crystallin chaperone mechanism envisions a transition from the native oligomer to an activated form that has higher affinity to non-native states of the substrate. Previous studies have suggested that this oligomeric plasticity is encoded in the primary sequence and controls access to high affinity binding sites within the N-terminal domain. Here, we further examined the role of sequence variation in the context of species-specific α-crystallins from rat and zebrafish. Alternative splicing of the αA gene in rodents produces αA(ins), which is distinguished by a longer N-terminal domain. The zebrafish genome includes duplicate αB-crystallin genes, αBa and αBb, which display divergent primary sequence and tissue expression patterns. Equilibrium binding experiments were employed to quantitatively define chaperone interactions with a destabilized model substrate, T4 lysozyme. In combination with multiangle light scattering, we show that rat αA(ins) and zebrafish α-crystallins display distinct global structural properties and chaperone activities. Notably, we find that αA(ins) and αBa demonstrate substantially enhanced chaperone function relative to other α-crystallins, binding the same substrate more than 2 orders of magnitude higher affinity and mimicking the activity of fully activated mammalian small heat shock proteins. These results emphasize the role of sequence divergence as an evolutionary strategy to tune chaperone function to the requirements of the tissues and organisms in which they are expressed.
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Affiliation(s)
- Hanane A Koteiche
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine , Nashville, Tennessee 37232, United States
| | - Derek P Claxton
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine , Nashville, Tennessee 37232, United States
| | - Sanjay Mishra
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine , Nashville, Tennessee 37232, United States
| | - Richard A Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine , Nashville, Tennessee 37232, United States
| | - Ezelle T McDonald
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine , Nashville, Tennessee 37232, United States
| | - Hassane S Mchaourab
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine , Nashville, Tennessee 37232, United States
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Mueller NH, Fogueri U, Pedler MG, Montana K, Petrash JM, Ammar DA. Impact of Subunit Composition on the Uptake of α-Crystallin by Lens and Retina. PLoS One 2015; 10:e0137659. [PMID: 26355842 PMCID: PMC4565700 DOI: 10.1371/journal.pone.0137659] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 08/19/2015] [Indexed: 11/30/2022] Open
Abstract
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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Affiliation(s)
- Niklaus H. Mueller
- Department of Ophthalmology, University of Colorado School of Medicine, Aurora, Colorado, United States of America
- * E-mail:
| | - Uma Fogueri
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy, University of Colorado, Aurora, Colorado, United States of America
| | - Michelle G. Pedler
- Department of Ophthalmology, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - Kameron Montana
- Department of Ophthalmology, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - J. Mark Petrash
- Department of Ophthalmology, University of Colorado School of Medicine, Aurora, Colorado, United States of America
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy, University of Colorado, Aurora, Colorado, United States of America
| | - David A. Ammar
- Department of Ophthalmology, University of Colorado School of Medicine, Aurora, Colorado, United States of America
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