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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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Aísa-Marín I, Rovira Q, Díaz N, Calvo-López L, Vaquerizas JM, Marfany G. Specific photoreceptor cell fate pathways are differentially altered in NR2E3-associated diseases. Neurobiol Dis 2024; 194:106463. [PMID: 38485095 DOI: 10.1016/j.nbd.2024.106463] [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: 12/27/2023] [Revised: 03/01/2024] [Accepted: 03/02/2024] [Indexed: 03/21/2024] Open
Abstract
Mutations in NR2E3, a gene encoding an orphan nuclear transcription factor, cause two retinal dystrophies with a distinct phenotype, but the precise role of NR2E3 in rod and cone transcriptional networks remains unclear. To dissect NR2E3 function, we performed scRNA-seq in the retinas of wildtype and two different Nr2e3 mouse models that show phenotypes similar to patients carrying NR2E3 mutations. Our results reveal that rod and cone populations are not homogeneous and can be separated into different sub-classes. We identify a previously unreported cone pathway that generates hybrid cones co-expressing both cone- and rod-related genes. In mutant retinas, this hybrid cone subpopulation is more abundant and includes a subpopulation of rods transitioning towards a cone cell fate. Hybrid photoreceptors with high misexpression of cone- and rod-related genes are prone to regulated necrosis. Overall, our results shed light on the role of NR2E3 in modulating photoreceptor differentiation towards cone and rod fates and explain how different mutations in NR2E3 lead to distinct visual disorders in humans.
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Affiliation(s)
- Izarbe Aísa-Marín
- Department de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Barcelona 08028, Spain; IBUB-IRSJD, Institut de Biomedicina de la Universitat de Barcelona-Institut de Recerca Sant Joan de Déu, Barcelona 08028, Spain; CIBERER, Instituto de Salud Carlos III, Barcelona 08028, Spain
| | - Quirze Rovira
- Max-Planck-Institute for Molecular Biomedicine, Münster 48149, Germany
| | - Noelia Díaz
- Max-Planck-Institute for Molecular Biomedicine, Münster 48149, Germany
| | - Laura Calvo-López
- Department de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Barcelona 08028, Spain
| | - Juan M Vaquerizas
- Max-Planck-Institute for Molecular Biomedicine, Münster 48149, Germany; MRC London Institute of Medical Sciences, Institute of Clinical Sciences, Imperial College London, London W12 0NN, UK.; Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0NN, UK.
| | - Gemma Marfany
- Department de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Barcelona 08028, Spain; IBUB-IRSJD, Institut de Biomedicina de la Universitat de Barcelona-Institut de Recerca Sant Joan de Déu, Barcelona 08028, Spain; CIBERER, Instituto de Salud Carlos III, Barcelona 08028, Spain; DBGen Ocular Genomics, Barcelona 08028, Spain.
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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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Starr CR, Zhylkibayev A, Mobley JA, Gorbatyuk MS. Proteomic analysis of diabetic retinas. Front Endocrinol (Lausanne) 2023; 14:1229089. [PMID: 37693346 PMCID: PMC10486886 DOI: 10.3389/fendo.2023.1229089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 07/28/2023] [Indexed: 09/12/2023] Open
Abstract
Introduction As a metabolic disease, diabetes often leads to health complications such as heart failure, nephropathy, neurological disorders, and vision loss. Diabetic retinopathy (DR) affects as many as 100 million people worldwide. The mechanism of DR is complex and known to impact both neural and vascular components in the retina. While recent advances in the field have identified major cellular signaling contributing to DR pathogenesis, little has been reported on the protein post-translational modifications (PTM) - known to define protein localization, function, and activity - in the diabetic retina overall. Protein glycosylation is the enzymatic addition of carbohydrates to proteins, which can influence many protein attributes including folding, stability, function, and subcellular localization. O-linked glycosylation is the addition of sugars to an oxygen atom in amino acids with a free oxygen atom in their side chain (i.e., threonine, serine). To date, more than 100 congenital disorders of glycosylation have been described. However, no studies have identified the retinal O-linked glycoproteome in health or disease. With a critical need to expedite the discovery of PTMomics in diabetic retinas, we identified both global changes in protein levels and the retinal O-glycoproteome of control and diabetic mice. Methods We used liquid chromatography/mass spectrometry-based proteomics and high throughput screening to identify proteins differentially expressed and proteins differentially O-glycosylated in the retinas of wildtype and diabetic mice. Results Changes in both global expression levels of proteins and proteins differentially glycosylated in the retinas of wild-type and diabetic mice have been identified. We provide evidence that diabetes shifts both global expression levels and O-glycosylation of metabolic and synaptic proteins in the retina. Discussion Here we report changes in the retinal proteome of diabetic mice. We highlight alterations in global proteins involved in metabolic processes, maintaining cellular structure, trafficking, and neuronal processes. We then showed changes in O-linked glycosylation of individual proteins in the diabetic retina.
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Affiliation(s)
- Christopher R. Starr
- Department of Optometry and Vision Science, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Assylbek Zhylkibayev
- Department of Optometry and Vision Science, University of Alabama at Birmingham, Birmingham, AL, United States
| | - James A. Mobley
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Marina S. Gorbatyuk
- Department of Optometry and Vision Science, University of Alabama at Birmingham, Birmingham, AL, United States
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Prokai L, Zaman K, Prokai-Tatrai K. Mass spectrometry-based retina proteomics. MASS SPECTROMETRY REVIEWS 2023; 42:1032-1062. [PMID: 35670041 PMCID: PMC9730434 DOI: 10.1002/mas.21786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/28/2022] [Accepted: 04/29/2022] [Indexed: 06/15/2023]
Abstract
A subfield of neuroproteomics, retina proteomics has experienced a transformative growth since its inception due to methodological advances in enabling chemical, biochemical, and molecular biology techniques. This review focuses on mass spectrometry's contributions to facilitate mammalian and avian retina proteomics to catalog and quantify retinal protein expressions, determine their posttranslational modifications, as well as its applications to study the proteome of the retina in the context of biology, health and diseases, and therapy developments.
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Affiliation(s)
- Laszlo Prokai
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Khadiza Zaman
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Katalin Prokai-Tatrai
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA
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Liu H, Bell K, Herrmann A, Arnhold S, Mercieca K, Anders F, Nagel-Wolfrum K, Thanos S, Prokosch V. Crystallins Play a Crucial Role in Glaucoma and Promote Neuronal Cell Survival in an In Vitro Model Through Modulating Müller Cell Secretion. Invest Ophthalmol Vis Sci 2022; 63:3. [PMID: 35816047 PMCID: PMC9284462 DOI: 10.1167/iovs.63.8.3] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The aim of this study was to explore the roles of crystallins in the context of aging in glaucoma and potential mechanisms of neuroprotection in an experimental animal model of glaucoma. Methods Intraocular pressure (IOP) was significantly elevated for 8 weeks in animals at different ages (10 days, 12 weeks, and 44 weeks) by episcleral vein cauterization. Retinal ganglion cells (RGCs) were quantified by anti-Brn3a immunohistochemical staining (IHC). Proteomics using ESI-LTQ Orbitrap XL-MS was used to analyze the presence and abundance of crystallin isoforms the retinal samples, respectively. Neuroprotective property and localization of three selected crystallins CRYAB, CRYBB2, and CRYGB as most significantly changed in retina and retinal layers were determined by IHC. Their expressions and endocytic uptakes into Müller cells were analyzed by IHC and Western blotting. Müller cell secretion of neurotrophic factors into the supernatant following CRYAB, CRYBB2, and CRYGB supplementation in vitro was measured via microarray. Results IOP elevation resulted in significant RGC loss in all age groups (P < 0.001). The loss increased with aging. Proteomics analysis revealed in parallel a significant decrease of crystallin abundance – especially CRYAB, CRYBB2, and CRYGB. Significant neuroprotective effects of CRYAB, CRYBB2, and CRYGB after addition to retinal cultures were demonstrated (P < 0.001). Endocytic uptake of CRYAB, CRYBB2, and CRYGB was seen in Müller cells with subsequent increased secretion of various neurotrophic factors into the supernatant, including nerve growth factor, clusterin, and matrix metallopeptidase 9. Conclusions An age-dependent decrease in CRYAB, CRYBB2, and CRYGB abundance is found going along with increased RGC loss. Addition of CRYAB, CRYBB2, and CRYGB to culture protected RGCs in vitro. CRYAB, CRYBB2, and CRYGB were uptaken into Müller cells. Secretion of neurotrophic factors was increased as a potential mode of action.
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Affiliation(s)
- Hanhan Liu
- Department of Ophthalmology, Faculty of Medicine and University Hospital of Cologne, University of Cologne, Cologne, Germany
| | - Katharina Bell
- Singapore Eye Research Institute and Singapore National Eye Center, Singapore; Duke-NUS Medical School, Singapore
| | - Anja Herrmann
- Institute of Veterinary Anatomy, Histology and Embryology, Justus-Liebig-University Gießen, Gießen, Germany
| | - Stefan Arnhold
- Institute of Veterinary Anatomy, Histology and Embryology, Justus-Liebig-University Gießen, Gießen, Germany
| | - Karl Mercieca
- Department of Ophthalmology, University Medical Center Bonn, Bonn, Germany
| | - Fabian Anders
- Department of Ophthalmology, University Medical Centre of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Kerstin Nagel-Wolfrum
- Institute for Molecular Physiology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Solon Thanos
- Department of Ophthalmology, Experimental Ophthalmology, University Medical Center Münster, Münster, Germany
| | - Verena Prokosch
- Department of Ophthalmology, Faculty of Medicine and University Hospital of Cologne, University of Cologne, Cologne, Germany
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Gharbi N, Røise D, Førre JE, Edson AJ, Hushagen HA, Tronci V, Frøyset AK, Fladmark KE. Reintroduction of DJ-1 in Müller Cells Inhibits Retinal Degeneration in the DJ-1 Deficient Retina. Antioxidants (Basel) 2021; 10:1862. [PMID: 34942966 PMCID: PMC8698414 DOI: 10.3390/antiox10121862] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 11/14/2021] [Accepted: 11/16/2021] [Indexed: 12/19/2022] Open
Abstract
The eye is continuously under oxidative stress due to high metabolic activity and reactive oxygen species generated by daily light exposure. The redox-sensitive protein DJ-1 has proven to be essential in order to protect retina and retinal pigment epithelium (RPE) from oxidative-stress-induced degeneration. Here, we analyzed the specific role of Müller cell DJ-1 in the adult zebrafish retina by re-establishing Müller-cell-specific DJ-1 expression in a DJ-1 knockout retina. Loss of DJ-1 resulted in an age-dependent retinal degeneration, including loss of cells in the ganglion cell layer, retinal thinning, photoreceptor disorganization and RPE cell dysfunction. The degenerative phenotype induced by the absence of DJ-1 was inhibited by solely expressing DJ-1 in Müller cells. The protective effect was dependent upon the cysteine-106 residue of DJ-1, which has been shown to be an oxidative sensor of DJ-1. In a label-free proteomics analysis of isolated retinas, we identified proteins differentially expressed after DJ-1 knockout, but with restored levels after Müller cell DJ-1 re-insertion. Our data show that Müller cell DJ-1 has a major role in protecting the retina from age-dependent oxidative stress.
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Affiliation(s)
- Naouel Gharbi
- Integrative Fish Biology Group (IFB), NORCE Norwegian Research Center AS, N-5020 Bergen, Norway; (N.G.); (V.T.)
| | - Dagne Røise
- Department of Biological Science, University of Bergen, N-5020 Bergen, Norway; (D.R.); (J.-E.F.); (A.J.E.); (H.A.H.); (A.-K.F.)
| | - Jorunn-Elise Førre
- Department of Biological Science, University of Bergen, N-5020 Bergen, Norway; (D.R.); (J.-E.F.); (A.J.E.); (H.A.H.); (A.-K.F.)
| | - Amanda J. Edson
- Department of Biological Science, University of Bergen, N-5020 Bergen, Norway; (D.R.); (J.-E.F.); (A.J.E.); (H.A.H.); (A.-K.F.)
| | - Helena A. Hushagen
- Department of Biological Science, University of Bergen, N-5020 Bergen, Norway; (D.R.); (J.-E.F.); (A.J.E.); (H.A.H.); (A.-K.F.)
| | - Valentina Tronci
- Integrative Fish Biology Group (IFB), NORCE Norwegian Research Center AS, N-5020 Bergen, Norway; (N.G.); (V.T.)
| | - Ann-Kristin Frøyset
- Department of Biological Science, University of Bergen, N-5020 Bergen, Norway; (D.R.); (J.-E.F.); (A.J.E.); (H.A.H.); (A.-K.F.)
| | - Kari E. Fladmark
- Department of Biological Science, University of Bergen, N-5020 Bergen, Norway; (D.R.); (J.-E.F.); (A.J.E.); (H.A.H.); (A.-K.F.)
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Phadte AS, Sluzala ZB, Fort PE. Therapeutic Potential of α-Crystallins in Retinal Neurodegenerative Diseases. Antioxidants (Basel) 2021; 10:1001. [PMID: 34201535 PMCID: PMC8300683 DOI: 10.3390/antiox10071001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 06/12/2021] [Accepted: 06/15/2021] [Indexed: 11/18/2022] Open
Abstract
The chaperone and anti-apoptotic activity of α-crystallins (αA- and αB-) and their derivatives has received increasing attention due to their tremendous potential in preventing cell death. While originally known and described for their role in the lens, the upregulation of these proteins in cells and animal models of neurodegenerative diseases highlighted their involvement in adaptive protective responses to neurodegeneration associated stress. However, several studies also suggest that chronic neurodegenerative conditions are associated with progressive loss of function of these proteins. Thus, while external supplementation of α-crystallin shows promise, their potential as a protein-based therapeutic for the treatment of chronic neurodegenerative diseases remains ambiguous. The current review aims at assessing the current literature supporting the anti-apoptotic potential of αA- and αB-crystallins and its potential involvement in retinal neurodegenerative diseases. The review further extends into potentially modulating the chaperone and the anti-apoptotic function of α-crystallins and the use of such functionally enhanced proteins for promoting neuronal viability in retinal neurodegenerative disease.
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Affiliation(s)
- Ashutosh S. Phadte
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA; (A.S.P.); (Z.B.S.)
| | - Zachary B. Sluzala
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA; (A.S.P.); (Z.B.S.)
| | - Patrice E. Fort
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA; (A.S.P.); (Z.B.S.)
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48105, USA
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Photobiomodulation Mediates Neuroprotection against Blue Light Induced Retinal Photoreceptor Degeneration. Int J Mol Sci 2020; 21:ijms21072370. [PMID: 32235464 PMCID: PMC7177783 DOI: 10.3390/ijms21072370] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 03/21/2020] [Accepted: 03/27/2020] [Indexed: 12/12/2022] Open
Abstract
Potent neuroprotective effects of photobiomodulation with 670 nm red light (RL) have been demonstrated in several models of retinal disease. RL improves mitochondrial metabolism, reduces retinal inflammation and oxidative cell stress, showing its ability to enhance visual function. However, the current knowledge is limited to the main hypothesis that the respiratory chain complex IV, cytochrome c oxidase, serves as the primary target of RL. Here, we demonstrate a comprehensive cellular, molecular, and functional characterization of neuroprotective effects of 670 nm RL and 810 nm near-infrared light (NIRL) on blue light damaged murine primary photoreceptors. We show that respiratory chain complexes I and II are additional PBM targets, besides complex IV, leading to enhanced mitochondrial energy metabolism. Accordingly, our study identified mitochondria related RL- and NIRL-triggered defense mechanisms promoting photoreceptor neuroprotection. The observed improvement of mitochondrial and extramitochondrial respiration in both inner and outer segments is linked with reduced oxidative stress including its cellular consequences and reduced mitochondria-induced apoptosis. Analysis of regulatory mechanisms using gene expression analysis identified upregulation α-crystallins that indicate enhanced production of proteins with protective functions that point to the rescued mitochondrial function. The results support the hypothesis that energy metabolism is a major target for retinal light therapy.
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Barabino A, Flamier A, Hanna R, Héon E, Freedman BS, Bernier G. Deregulation of Neuro-Developmental Genes and Primary Cilium Cytoskeleton Anomalies in iPSC Retinal Sheets from Human Syndromic Ciliopathies. Stem Cell Reports 2020; 14:357-373. [PMID: 32160518 PMCID: PMC7066374 DOI: 10.1016/j.stemcr.2020.02.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 02/10/2020] [Accepted: 02/11/2020] [Indexed: 01/22/2023] Open
Abstract
Ciliopathies are heterogeneous genetic diseases affecting primary cilium structure and function. Meckel-Gruber (MKS) and Bardet-Biedl (BBS) syndromes are severe ciliopathies characterized by skeletal and neurodevelopment anomalies, including polydactyly, cognitive impairment, and retinal degeneration. We describe the generation and molecular characterization of human induced pluripotent stem cell (iPSC)-derived retinal sheets (RSs) from controls, and MKS (TMEM67) and BBS (BBS10) cases. MKS and BBS RSs displayed significant common alterations in the expression of hundreds of developmental genes and members of the WNT and BMP pathways. Induction of crystallin molecular chaperones was prominent in MKS and BBS RSs suggesting a stress response to misfolded proteins. Unique to MKS photoreceptors was the presence of supernumerary centrioles and cilia, and aggregation of ciliary proteins. Unique to BBS photoreceptors was the accumulation of DNA damage and activation of the mitotic spindle checkpoint. This study reveals how combining cell reprogramming, organogenesis, and next-generation sequencing enables the elucidation of mechanisms involved in human ciliopathies.
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Affiliation(s)
- Andrea Barabino
- Stem Cell and Developmental Biology Laboratory, Hôpital Maisonneuve-Rosemont, 5415 Boul. Assomption, Montreal, QC H1T 2M4, Canada
| | - Anthony Flamier
- Stem Cell and Developmental Biology Laboratory, Hôpital Maisonneuve-Rosemont, 5415 Boul. Assomption, Montreal, QC H1T 2M4, Canada
| | - Roy Hanna
- Stem Cell and Developmental Biology Laboratory, Hôpital Maisonneuve-Rosemont, 5415 Boul. Assomption, Montreal, QC H1T 2M4, Canada
| | - Elise Héon
- Hospital for Sick Children, Department of Ophthalmology and Vision Sciences, Program of Genetics and Genome Biology, 555 University av., Toronto, ON M5G 1X8, Canada
| | - Benjamin S Freedman
- Department of Medicine, Division of Nephrology, Kidney Research Institute, and Institute of Stem Cell and Regenerative Medicine, and Department of Pathology, University of Washington School of Medicine, Seattle, WA 98109, USA.
| | - Gilbert Bernier
- Stem Cell and Developmental Biology Laboratory, Hôpital Maisonneuve-Rosemont, 5415 Boul. Assomption, Montreal, QC H1T 2M4, Canada; Department of Neurosciences, University of Montreal, Montreal, QC H3C 3J7, Canada; Department of Ophthalmology, University of Montreal, Montreal, QC H3C 3J7, Canada.
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Hamadmad S, Shah MH, Kusibati R, Kim B, Erickson B, Heisler-Taylor T, Bhattacharya SK, Abdel-Rahman MH, Cebulla CM. Significant upregulation of small heat shock protein αA-crystallin in retinal detachment. Exp Eye Res 2019; 189:107811. [PMID: 31550446 DOI: 10.1016/j.exer.2019.107811] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 08/21/2019] [Accepted: 09/18/2019] [Indexed: 10/25/2022]
Affiliation(s)
- Sumaya Hamadmad
- The Ohio State University Department of Ophthalmology and Visual Science, Havener Eye Institute, The Ohio State University Wexner Medical Center, 915 Olentangy River Road, Columbus, OH, 43212, USA
| | - Mohd Hussain Shah
- The Ohio State University Department of Ophthalmology and Visual Science, Havener Eye Institute, The Ohio State University Wexner Medical Center, 915 Olentangy River Road, Columbus, OH, 43212, USA
| | - Rania Kusibati
- The Ohio State University Department of Ophthalmology and Visual Science, Havener Eye Institute, The Ohio State University Wexner Medical Center, 915 Olentangy River Road, Columbus, OH, 43212, USA
| | - Bongsu Kim
- The Ohio State University Department of Ophthalmology and Visual Science, Havener Eye Institute, The Ohio State University Wexner Medical Center, 915 Olentangy River Road, Columbus, OH, 43212, USA
| | - Brandon Erickson
- The Ohio State University Department of Ophthalmology and Visual Science, Havener Eye Institute, The Ohio State University Wexner Medical Center, 915 Olentangy River Road, Columbus, OH, 43212, USA
| | - Tyler Heisler-Taylor
- The Ohio State University Department of Ophthalmology and Visual Science, Havener Eye Institute, The Ohio State University Wexner Medical Center, 915 Olentangy River Road, Columbus, OH, 43212, USA
| | - Sanjoy K Bhattacharya
- Bascom Palmer Eye Institute, Department of Ophthalmology, The Miller School of Medicine, Miami, FL, 33136, USA
| | - Mohamed H Abdel-Rahman
- The Ohio State University Department of Ophthalmology and Visual Science, Havener Eye Institute, The Ohio State University Wexner Medical Center, 915 Olentangy River Road, Columbus, OH, 43212, USA; Division Human Genetics, The Ohio State University Wexner Medical Center, Columbus, OH, 43240, USA
| | | | - Colleen M Cebulla
- The Ohio State University Department of Ophthalmology and Visual Science, Havener Eye Institute, The Ohio State University Wexner Medical Center, 915 Olentangy River Road, Columbus, OH, 43212, USA.
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Botling Taube A, Konzer A, Alm A, Bergquist J. Proteomic analysis of the aqueous humour in eyes with pseudoexfoliation syndrome. Br J Ophthalmol 2019; 103:1190-1194. [PMID: 30842085 PMCID: PMC6678048 DOI: 10.1136/bjophthalmol-2017-310416] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 12/05/2018] [Accepted: 02/06/2019] [Indexed: 11/06/2022]
Abstract
Background/aims Pseudoexfoliation syndrome (PEX) is characterised by the production and accumulation of extracellular fibrillar material in the anterior segment of the eye. The pathogenesis of PEX is multifactorial with genetic factors and ageing as contributing factors. Previously, an increased concentration of beta-crystalline B2 (CRYBB2) was observed in the aqueous humour (AH) in eyes with PEX in a pooled material. Here, the protein content was examined on individual basis. Methods During cataract surgery, AH was sampled from patients with and without PEX, 10 eyes in each group. The proteins were digested and labelled with isotopomeric dimethyl labels, separated with high-pressure liquid chromatography and analysed in an Orbitrap mass analyzer. Results The concentration of complement factor 3, kininogen-1, antithrombin III and vitamin D-binding protein was increased in all eyes with PEX. Retinol-binding protein 3, glutathione peroxidase, calsyntenin-1 and carboxypeptidase E were decreased in eyes with PEX. Beta-crystalline B1 and CRYBB2 and gamma-crystalline D were up to eightfold upregulated in 4 of 10 in eyes with PEX. Conclusion The results indicate that oxidative stress and inflammation are contributing factors in the formation of PEX. Knowledge about the proteome in PEX is relevant for understanding this condition.
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Affiliation(s)
- Amelie Botling Taube
- Department of Neuroscience, Uppsala University, Uppsala, Sweden.,St Erik Eye Hospital, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Anne Konzer
- Analytical Chemistry and Neurochemistry, Department of Chemistry-BMC, Uppsala University, Uppsala, Sweden
| | - Albert Alm
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Jonas Bergquist
- Analytical Chemistry and Neurochemistry, Department of Chemistry-BMC, Uppsala University, Uppsala, Sweden
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13
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Wang R, Chen ZH, Wang Y, Huang HB, Fan SJ, Chen LL. Recombination and identification of human alpha B-crystallin. Int J Ophthalmol 2018; 11:1916-1921. [PMID: 30588422 DOI: 10.18240/ijo.2018.12.06] [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: 05/16/2018] [Accepted: 10/22/2018] [Indexed: 11/23/2022] Open
Abstract
AIM To recombine the human alpha B-crystallin (αB-crystallin) using gene cloning technology and prokaryotic expression vector and confirm the biological activity of recombinant human αB-crystallin. METHODS Cloning the human αB-crystallin cDNA according to the nucleotide sequence of the human αB-crystallin, constructing the pET-28/CRYAB prokaryotic expression plasmid by restriction enzyme digestion method, and stably expressing transformed into the Escherichia coli (E. coli) DH5 alpha. The recombinant human αB-crystallin was purified by Q sepharose. By enzyme digestion analysis, Western blotting and sequencing, the recombinant human αB-crystallin was identified and the activity of its molecular protein was detected. RESULTS Compared with the gene bank (GeneBank), the cloned human sequence of human αB-crystallin cDNA has the same open reading frame. Identification and sequencing of the cloned human αB-crystallin cDNA in prokaryotic expression vector confirmed the full length sequence, and the vector was constructed successfully. The E. coli containing plasmid pET-28/CRYAB induced by isopropyl-β-D-thiogalactoside successfully expressed the human αB-crystallin. Insulin confirmed that the recombinant human αB-crystallin has a molecular chaperone activity. CONCLUSION The prokaryotic expression vector pET-28/CRYAB of recombinant human αB-crystallin is successfully constructed, and the recombinant human αB-crystallin with molecular chaperone activity is obtained, which lay a foundation for the research and application of the recombinant human αB-crystallin and its chaperone activity.
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Affiliation(s)
- Rui Wang
- Department of Ophthalmology, Hainan Branch of PLA General Hospital, Sanya 572000, Hainan Province, China
| | - Ze-Hua Chen
- Department of Ophthalmology, Hainan Branch of PLA General Hospital, Sanya 572000, Hainan Province, China
| | - Yi Wang
- Chongqing Aier General Hospital, Aier School of Ophthalmology, Central South University, Chongqing 400020, China
| | - Hou-Bin Huang
- Department of Ophthalmology, Hainan Branch of PLA General Hospital, Sanya 572000, Hainan Province, China
| | - Si-Jun Fan
- PLA Rocket Force General Hospital, Beijing 100088, China
| | - Lan-Lan Chen
- Department of Ophthalmology, Hainan Branch of PLA General Hospital, Sanya 572000, Hainan Province, China
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14
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Zayas-Santiago A, Ríos DS, Zueva LV, Inyushin MY. Localization of αA-Crystallin in Rat Retinal Müller Glial Cells and Photoreceptors. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2018; 24:545-552. [PMID: 30253817 PMCID: PMC6378655 DOI: 10.1017/s1431927618015118] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 07/17/2018] [Accepted: 08/18/2018] [Indexed: 06/01/2023]
Abstract
Transparent cells in the vertebrate optical tract, such as lens fiber cells and corneal epithelium cells, have specialized proteins that somehow permit only a low level of light scattering in their cytoplasm. It has been shown that both cell types contain (1) beaded intermediate filaments as well as (2) α-crystallin globulins. It is known that genetic and chemical alterations to these specialized proteins induce cytoplasmic opaqueness and visual complications. Crystallins were described previously in the retinal Müller cells of frogs. In the present work, using immunocytochemistry, fluorescence confocal imaging, and immuno-electron microscopy, we found that αA-crystallins are present in the cytoplasm of retinal Müller cells and in the photoreceptors of rats. Given that Müller glial cells were recently described as "living light guides" as were photoreceptors previously, we suggest that αA-crystallins, as in other highly transparent cells, allow Müller cells and photoreceptors to minimize intraretinal scattering during retinal light transmission.
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Affiliation(s)
- Astrid Zayas-Santiago
- Department of Pathology and Laboratory Medicine, Universidad Central del Caribe, Bayamón, PR 00960, USA
| | - David S. Ríos
- College of Science and Health Professions, Universidad Central de Bayamón, Bayamón, PR00960, USA
| | - Lidia V. Zueva
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 194223 St-Petersburg, Russia
| | - Mikhail Y. Inyushin
- Department of Physiology, Universidad Central del Caribe, Bayamón, PR 00960, USA
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15
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Rübsam A, Parikh S, Fort PE. Role of Inflammation in Diabetic Retinopathy. Int J Mol Sci 2018; 19:ijms19040942. [PMID: 29565290 PMCID: PMC5979417 DOI: 10.3390/ijms19040942] [Citation(s) in RCA: 438] [Impact Index Per Article: 73.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 03/09/2018] [Accepted: 03/17/2018] [Indexed: 02/07/2023] Open
Abstract
Diabetic retinopathy is a common complication of diabetes and remains the leading cause of blindness among the working-age population. For decades, diabetic retinopathy was considered only a microvascular complication, but the retinal microvasculature is intimately associated with and governed by neurons and glia, which are affected even prior to clinically detectable vascular lesions. While progress has been made to improve the vascular alterations, there is still no treatment to counteract the early neuro-glial perturbations in diabetic retinopathy. Diabetes is a complex metabolic disorder, characterized by chronic hyperglycemia along with dyslipidemia, hypoinsulinemia and hypertension. Increasing evidence points to inflammation as one key player in diabetes-associated retinal perturbations, however, the exact underlying molecular mechanisms are not yet fully understood. Interlinked molecular pathways, such as oxidative stress, formation of advanced glycation end-products and increased expression of vascular endothelial growth factor have received a lot of attention as they all contribute to the inflammatory response. In the current review, we focus on the involvement of inflammation in the pathophysiology of diabetic retinopathy with special emphasis on the functional relationships between glial cells and neurons. Finally, we summarize recent advances using novel targets to inhibit inflammation in diabetic retinopathy.
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Affiliation(s)
- Anne Rübsam
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA.
| | - Sonia Parikh
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA.
| | - Patrice E Fort
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA.
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48105, USA.
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16
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Naiman MI, Bouhenni R, Ansari RR, Dunmire J, Liu Y, Rafiq Q, Edward D. Non-invasive Detection of Unique Molecular Signatures in Laser-Induced Retinal Injuries. Mil Med 2018; 183:18-27. [PMID: 29635604 DOI: 10.1093/milmed/usx213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 12/22/2017] [Indexed: 11/13/2022] Open
Abstract
Unintentional laser exposure is an increasing concern in many operational environments. Determining whether a laser exposure event caused a retinal injury currently requires medical expertise and specialized equipment that are not always readily available. The purpose of this study is to test the feasibility of using dynamic light scattering (DLS) to non-invasively detect laser retinal injuries through interrogation of the vitreous humor (VH). Three grades of retinal laser lesions were studied: mild (minimally visible lesions), moderate (Grade II), and severe (Grade III). A pre-post-treatment design was used to collect DLS measurements in vivo at various time points, using a customized instrument. VH samples were analyzed by liquid chromatography/tandem mass spectrometry (LC-MS/MS) and relative protein abundances were determined by spectral counting. DLS signal analysis revealed significant changes in particle diameter and intensity in laser-treated groups as compared with control. Differences in protein profile in the VH of the laser-treated eyes were noted when compared with control. These results suggest that laser injury to the retina induces upregulation of proteins that diffuse into the VH from the damaged tissue, which can be detected non-invasively using DLS.
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Affiliation(s)
- Melissa I Naiman
- Collaborative for Research, Design, and Evaluation, University of Illinois at Chicago, 2121W. Taylor Street, Chicago, IL 60612
| | - Rachida Bouhenni
- Department of Ophthalmology, Summa Health System, 525 E. Market Street, Akron, OH 44304
| | - Rafat R Ansari
- National Aeronautics and Space Administration-John H. Glenn Research Center, 21000 Brookpark Road, Cleveland, OH 44135
| | - Jeffrey Dunmire
- Department of Ophthalmology, Summa Health System, 525 E. Market Street, Akron, OH 44304
| | - Ying Liu
- Wilmer Eye Institute, John Hopkins University John School of Medicine, 600N. Wolfe Street, Baltimore, MD 21287
| | - Qundeel Rafiq
- Wilmer Eye Institute, John Hopkins University John School of Medicine, 600N. Wolfe Street, Baltimore, MD 21287
| | - Deepak Edward
- Wilmer Eye Institute, John Hopkins University John School of Medicine, 600N. Wolfe Street, Baltimore, MD 21287
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17
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Chiha W, LeVaillant CJ, Bartlett CA, Hewitt AW, Melton PE, Fitzgerald M, Harvey AR. Retinal genes are differentially expressed in areas of primary versus secondary degeneration following partial optic nerve injury. PLoS One 2018; 13:e0192348. [PMID: 29425209 PMCID: PMC5806857 DOI: 10.1371/journal.pone.0192348] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 01/20/2018] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Partial transection (PT) of the optic nerve is an established experimental model of secondary degeneration in the central nervous system. After a dorsal transection, retinal ganglion cells (RGCs) with axons in ventral optic nerve are intact but vulnerable to secondary degeneration, whereas RGCs in dorsal retina with dorsal axons are affected by primary and secondary injuries. Using microarray, we quantified gene expression changes in dorsal and ventral retina at 1 and 7 days post PT, to characterize pathogenic pathways linked to primary and secondary degeneration. RESULTS In comparison to uninjured retina Cryba1, Cryba2 and Crygs, were significantly downregulated in injured dorsal retina at days 1 and 7. While Ecel1, Timp1, Mt2A and CD74, which are associated with reducing excitotoxicity, oxidative stress and inflammation, were significantly upregulated. Genes associated with oxygen binding pathways, immune responses, cytokine receptor activity and apoptosis were enriched in dorsal retina at day 1 after PT. Oxygen binding and apoptosis remained enriched at day 7, as were pathways involved in extracellular matrix modification. Fewer changes were observed in ventral retina at day 1 after PT, most associated with the regulation of protein homodimerization activity. By day 7, apoptosis, matrix organization and signal transduction pathways were enriched. Discriminant analysis was also performed for specific functional gene groups to compare expression intensities at each time point. Altered expression of selected genes (ATF3, GFAP, Ecel1, TIMP1, Tp53) and proteins (GFAP, ECEL1 and ATF3) were semi-quantitatively assessed by qRT-PCR and immunohistochemistry respectively. CONCLUSION There was an acute and complex primary injury response in dorsal retina indicative of a dynamic interaction between neuroprotective and neurodegenerative events; ventral retina vulnerable to secondary degeneration showed a delayed injury response. Both primary and secondary injury resulted in the upregulation of numerous genes linked to RGC death, but differences in the nature of these changes strongly suggest that death occurred via different molecular mechanisms.
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Affiliation(s)
- Wissam Chiha
- Experimental and Regenerative Neurosciences, The University of Western Australia, Crawley, WA, Australia
- School of Human Sciences, The University of Western Australia, Crawley, WA, Australia
- School of Biological Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Chrisna J. LeVaillant
- School of Human Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Carole A. Bartlett
- School of Biological Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Alex W. Hewitt
- Lions Eye Institute, The University of Western Australia, Nedlands, WA, Australia
| | - Phillip E. Melton
- Curtin/UWA Centre for Genetic Origins of Health and Disease, School of Biomedical Science, The University of Western Australia and Curtin University, Bentley, WA, Australia
| | - Melinda Fitzgerald
- Experimental and Regenerative Neurosciences, The University of Western Australia, Crawley, WA, Australia
- School of Biological Sciences, The University of Western Australia, Crawley, WA, Australia
- Perron Institute for Neurological and Translational Science, QEII Medical Centre, Nedlands, WA, Australia
- Curtin Health Innovation Research Institute, Curtin University, Bentley, WA, Australia
| | - Alan R. Harvey
- Experimental and Regenerative Neurosciences, The University of Western Australia, Crawley, WA, Australia
- School of Human Sciences, The University of Western Australia, Crawley, WA, Australia
- Perron Institute for Neurological and Translational Science, QEII Medical Centre, Nedlands, WA, Australia
- * E-mail:
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18
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Márkus B, Pató Z, Sarang Z, Albert R, Tőzsér J, Petrovski G, Csősz É. The proteomic profile of a mouse model of proliferative vitreoretinopathy. FEBS Open Bio 2017; 7:1166-1177. [PMID: 28781956 PMCID: PMC5537063 DOI: 10.1002/2211-5463.12252] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 05/02/2017] [Accepted: 05/27/2017] [Indexed: 11/24/2022] Open
Abstract
Proliferative vitreoretinopathy (PVR) develops as a complication of retinal detachment surgery and represents a devastating condition leading to serious vision loss. A good animal model that permits extensive functional studies and drug testing is crucial in finding better therapeutic modalities for PVR. A previously established mouse model, using dispase injection, was analyzed from the proteomic point of view, examining global protein profile changes by 2D electrophoresis, image analysis and HPLC–tandem mass spectrometry‐based protein identification. The easy applicability of the mouse model was used to study the role of transglutaminase 2 (TG2) in PVR formation by proteomic examination of dispase‐induced TG2 knockout vitreous samples. Our data demonstrate that, despite the altered appearance of crystallin proteins, the lack of TG2 did not prevent the development of PVR.
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Affiliation(s)
- Bernadett Márkus
- Department of Biochemistry and Molecular Biology Faculty of Medicine University of Debrecen Hungary
| | - Zsuzsanna Pató
- Department of Biochemistry and Molecular Biology Faculty of Medicine University of Debrecen Hungary
| | - Zsolt Sarang
- Department of Biochemistry and Molecular Biology Faculty of Medicine University of Debrecen Hungary
| | - Réka Albert
- Department of Ophthalmology Faculty of Medicine University of Szeged Hungary
| | - József Tőzsér
- Department of Biochemistry and Molecular Biology Faculty of Medicine University of Debrecen Hungary
| | - Goran Petrovski
- Department of Ophthalmology Faculty of Medicine University of Szeged Hungary.,Department of Ophthalmology Oslo University Hospital and University of Oslo Norway
| | - Éva Csősz
- Department of Biochemistry and Molecular Biology Faculty of Medicine University of Debrecen Hungary
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Piri N, Kwong JMK, Gu L, Caprioli J. Heat shock proteins in the retina: Focus on HSP70 and alpha crystallins in ganglion cell survival. Prog Retin Eye Res 2016; 52:22-46. [PMID: 27017896 PMCID: PMC4842330 DOI: 10.1016/j.preteyeres.2016.03.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Revised: 03/14/2016] [Accepted: 03/22/2016] [Indexed: 10/22/2022]
Abstract
Heat shock proteins (HSPs) belong to a superfamily of stress proteins that are critical constituents of a complex defense mechanism that enhances cell survival under adverse environmental conditions. Cell protective roles of HSPs are related to their chaperone functions, antiapoptotic and antinecrotic effects. HSPs' anti-apoptotic and cytoprotective characteristics, their ability to protect cells from a variety of stressful stimuli, and the possibility of their pharmacological induction in cells under pathological stress make these proteins an attractive therapeutic target for various neurodegenerative diseases; these include Alzheimer's, Parkinson's, Huntington's, prion disease, and others. This review discusses the possible roles of HSPs, particularly HSP70 and small HSPs (alpha A and alpha B crystallins) in enhancing the survival of retinal ganglion cells (RGCs) in optic neuropathies such as glaucoma, which is characterized by progressive loss of vision caused by degeneration of RGCs and their axons in the optic nerve. Studies in animal models of RGC degeneration induced by ocular hypertension, optic nerve crush and axotomy show that upregulation of HSP70 expression by hyperthermia, zinc, geranyl-geranyl acetone, 17-AAG (a HSP90 inhibitor), or through transfection of retinal cells with AAV2-HSP70 effectively supports the survival of injured RGCs. RGCs survival was also stimulated by overexpression of alpha A and alpha B crystallins. These findings provide support for translating the HSP70- and alpha crystallin-based cell survival strategy into therapy to protect and rescue injured RGCs from degeneration associated with glaucomatous and other optic neuropathies.
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Affiliation(s)
- Natik Piri
- Stein Eye Institute, University of California, Los Angeles, CA 90095, USA; Brain Research Institute, University of California, Los Angeles, CA 90095, USA.
| | - Jacky M K Kwong
- Stein Eye Institute, University of California, Los Angeles, CA 90095, USA
| | - Lei Gu
- Stein Eye Institute, University of California, Los Angeles, CA 90095, USA
| | - Joseph Caprioli
- Stein Eye Institute, University of California, Los Angeles, CA 90095, USA; Brain Research Institute, University of California, Los Angeles, CA 90095, USA
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Panda AK, Nandi SK, Chakraborty A, Nagaraj RH, Biswas A. Differential role of arginine mutations on the structure and functions of α-crystallin. Biochim Biophys Acta Gen Subj 2015; 1860:199-210. [PMID: 26080000 DOI: 10.1016/j.bbagen.2015.06.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 05/22/2015] [Accepted: 06/09/2015] [Indexed: 11/29/2022]
Abstract
BACKGROUND α-Crystallin is a major protein of the eye lens in vertebrates. It is composed of two subunits, αA- and αB-crystallin. α-Crystallin is an oligomeric protein having these two subunits in 3:1 ratio. It belongs to small heat shock protein family and exhibits molecular chaperone function, which plays an important role in maintaining the lens transparency. Apart from chaperone function, both subunits also exhibit anti-apoptotic property. Comparison of their primary sequences reveals that αA- and αB-crystallin posses 13 and 14 arginine residues, respectively. Several of them undergo mutations which eventually lead to various eye diseases such as congenital cataract, juvenile cataract, and retinal degeneration. Interestingly, many arginine residues of these subunits are modified during glycation and even some are truncated during aging. All these facts indicate the importance of arginine residues in α-crystallin. SCOPE OF REVIEW In this review, we will emphasize the recent in vitro and in vivo findings related to congenital cataract causing arginine mutations in α-crystallin. MAJOR CONCLUSIONS Congenital cataract causing arginine mutations alters the structure and decreases the chaperone function of α-crystallin. These mutations also affect the lens morphology and phenotypes. Interestingly, non-natural arginine mutations (generated for mimicking the glycation and truncation environment) improve the chaperone function of α-crystallin which may play an important role in maintaining the eye lens transparency during aging. GENERAL SIGNIFICANCE The neutralization of positive charge on the guanidino group of arginine residues is not always detrimental to the functionality of α-crystallin. This article is part of a Special Issue entitled Crystallin Biochemistry in Health and Disease.
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Affiliation(s)
- Alok Kumar Panda
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar, Odisha 751013, India
| | - Sandip Kumar Nandi
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar, Odisha 751013, India
| | - Ayon Chakraborty
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar, Odisha 751013, India
| | - Ram H Nagaraj
- Department of Ophthalmology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Ashis Biswas
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar, Odisha 751013, India.
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Crystallins and neuroinflammation: The glial side of the story. Biochim Biophys Acta Gen Subj 2015; 1860:278-86. [PMID: 26049079 DOI: 10.1016/j.bbagen.2015.05.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 05/18/2015] [Accepted: 05/27/2015] [Indexed: 12/31/2022]
Abstract
BACKGROUND There is an abundance of evidence to support the association of damaging neuroinflammation and neurodegeneration across a multitude of diseases. One of the links between these pathological phenomena is the role of chaperone proteins as both neuroprotective and immune-regulatory agents. SCOPE OF REVIEW Chaperone proteins are highly expressed at sites of neuroinflammation both in glial cells and in the injured neurons that initiate the immune response. For this reason, the use of chaperones as treatment for various diseases associated with neuroinflammation is a highly active area of investigation. This review explores the various ways that the small heat shock protein chaperones, α-crystallins, can affect glial cell function with a specific focus on their implication in the inflammatory response associated with neurodegenerative disorders, and their potential as therapeutic treatment. MAJOR CONCLUSIONS Although the mechanisms are still under investigation, a clear link has now been established between alpha-crystallins and neuroinflammation, especially through their roles in microglial and macroglial cells. Interestingly, similar to inflammation in itself, crystallins can have a beneficial or detrimental impact on the CNS based on the context and duration of the condition. GENERAL SIGNIFICANCE Overall this review points out the novel roles that chaperones such as alpha-crystallins can play outside of the classical protein folding pathways, and their potential in the development of new therapies for the treatment of neuroinflammatory/neurodegenerative diseases. This article is part of a Special Issue entitled Crystallin Biochemistry in Health and Disease.
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22
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Protection of retina by mini-αA in NaIO3-induced retinal pigment epithelium degeneration mice. Int J Mol Sci 2015; 16:1644-56. [PMID: 25588217 PMCID: PMC4307325 DOI: 10.3390/ijms16011644] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 12/26/2014] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Studies have shown that mini-αA can protect retinal pigment epithelium (RPE) cells from apoptosis. However, no in vivo study concerning the anti-apoptotic function of mini-αA has been conducted yet. METHODS MTT assay, HE staining and TUNEL assay were used to assess levels of cells, and an animal model was established to examine the protective effects of mini-αA against NaIO3-induced RPE cell apoptosis. Western blot analysis and RT-qPCR were performed to explore the possible mechanism of mini-αA's protective function against NaIO3-induced RPE cell apoptosis. RESULTS RESULTS from in vivo and animal experiments showed that mini-αA antagonized NaIO3-induced RPE cell apoptosis. Further investigation into how mini-αA provided protection against NaIO3-induced RPE cell apoptosis showed that mini-αA reduced NaIO3-induced RPE cell apoptosis and autophagy. In addition, unfolded protein response was also involved in the protective effects of mini-αA against NaIO3-induced RPE cell apoptosis. CONCLUSIONS mini-αA can antagonize RPE cell apoptosis induced by NaIO3. A possible mechanism is by inhibition of apoptosis by repressing autophagy and endoplasmic reticulum stress.
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Thanos S, Böhm MR, Meyer zu Hörste M, Prokosch-Willing V, Hennig M, Bauer D, Heiligenhaus A. Role of crystallins in ocular neuroprotection and axonal regeneration. Prog Retin Eye Res 2014; 42:145-61. [DOI: 10.1016/j.preteyeres.2014.06.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 06/06/2014] [Accepted: 06/22/2014] [Indexed: 11/30/2022]
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Slingsby C, Wistow GJ. Functions of crystallins in and out of lens: roles in elongated and post-mitotic cells. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 115:52-67. [PMID: 24582830 PMCID: PMC4104235 DOI: 10.1016/j.pbiomolbio.2014.02.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Accepted: 02/18/2014] [Indexed: 12/25/2022]
Abstract
The vertebrate lens evolved to collect light and focus it onto the retina. In development, the lens grows through massive elongation of epithelial cells possibly recapitulating the evolutionary origins of the lens. The refractive index of the lens is largely dependent on high concentrations of soluble proteins called crystallins. All vertebrate lenses share a common set of crystallins from two superfamilies (although other lineage specific crystallins exist). The α-crystallins are small heat shock proteins while the β- and γ-crystallins belong to a superfamily that contains structural proteins of uncertain function. The crystallins are expressed at very high levels in lens but are also found at lower levels in other cells, particularly in retina and brain. All these proteins have plausible connections to maintenance of cytoplasmic order and chaperoning of the complex molecular machines involved in the architecture and function of cells, particularly elongated and post-mitotic cells. They may represent a suite of proteins that help maintain homeostasis in such cells that are at risk from stress or from the accumulated insults of aging.
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Affiliation(s)
- Christine Slingsby
- Department of Biological Sciences, Crystallography, Institute of Structural and Molecular Biology, Birkbeck College, Malet Street, London WC1E 7HX, UK.
| | - Graeme J Wistow
- Section on Molecular Structure and Functional Genomics, National Eye Institute, Bg 6, Rm 106, National Institutes of Health, Bethesda, MD 20892-0608, USA
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25
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Zhou P, Kannan R, Spee C, Sreekumar PG, Dou G, Hinton DR. Protection of retina by αB crystallin in sodium iodate induced retinal degeneration. PLoS One 2014; 9:e98275. [PMID: 24874187 PMCID: PMC4038555 DOI: 10.1371/journal.pone.0098275] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Accepted: 04/29/2014] [Indexed: 12/21/2022] Open
Abstract
Age-related macular degeneration (AMD) is a leading cause of blindness in the developed world. The retinal pigment epithelium (RPE) is a critical site of pathology in AMD and αB crystallin expression is increased in RPE and associated drusen in AMD. The purpose of this study was to investigate the role of αB crystallin in sodium iodate (NaIO3)-induced retinal degeneration, a model of AMD in which the primary site of pathology is the RPE. Dose dependent effects of intravenous NaIO3 (20-70 mg/kg) on development of retinal degeneration (fundus photography) and RPE and retinal neuronal loss (histology) were determined in wild type and αB crystallin knockout mice. Absence of αB crystallin augmented retinal degeneration in low dose (20 mg/kg) NaIO3-treated mice and increased retinal cell apoptosis which was mainly localized to the RPE layer. Generation of reactive oxygen species (ROS) was observed with NaIO3 in mouse and human RPE which increased further after αB crystallin knockout or siRNA knockdown, respectively. NaIO3 upregulated AKT phosphorylation and peroxisome proliferator–activator receptor–γ (PPARγ) which was suppressed after αB crystallin siRNA knockdown. Further, PPARγ ligand inhibited NaIO3-induced ROS generation. Our data suggest that αB crystallin plays a critical role in protection of NaIO3-induced oxidative stress and retinal degeneration in part through upregulation of AKT phosphorylation and PPARγ expression.
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Affiliation(s)
- Peng Zhou
- Doheny Eye Institute, Los Angeles, California, United States of America
| | - Ram Kannan
- Doheny Eye Institute, Los Angeles, California, United States of America
| | - Christine Spee
- Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States of America
| | | | - Guorui Dou
- Doheny Eye Institute, Los Angeles, California, United States of America
| | - David R. Hinton
- Departments of Pathology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States of America
- Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States of America
- * E-mail:
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Templeton JP, Wang X, Freeman NE, Ma Z, Lu A, Hejtmancik F, Geisert EE. A crystallin gene network in the mouse retina. Exp Eye Res 2013; 116:129-40. [PMID: 23978599 DOI: 10.1016/j.exer.2013.08.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 07/25/2013] [Accepted: 08/01/2013] [Indexed: 12/11/2022]
Abstract
The present study was designed to examine the regulation of crystallin genes and protein in the mouse retina using the BXD recombinant inbred (RI) strains. Illumina Sentrix BeadChip Arrays (MouseWG-6v2) were used to analyze mRNA levels in 75 BXD RI strains along with the parental strains (C57Bl/6J and DBA/2J), and the reciprocal crosses in the Hamilton Eye Institute (HEI) Retina Dataset (www.genenetwork.org). Protein levels were investigated using immunoblots to quantify levels of proteins and indirect immunohistochemistry to define the distribution of protein. Algorithms in the Genomatix program were used to identify transcription factor binding sites common to the regulatory sequences in the 5' regions of co-regulated set of crystallin and other genes as compared to a set of control genes. As subset of genes, including many encoding lens crystallins is part of a tightly co-regulated network that is active in the retina. Expression of this crystallin network appears to be binary in nature, being expressed either at relatively low levels or being highly upregulated. Relative to a control set of genes, the 5' regulatory sequences of the crystallin network genes show an increased frequency of a set of common transcription factor-binding sites, the most common being those of the Maf family. Chromatin immunoprecipitation of human lens epithelial cells (HLEC) and rat retinal ganglion cells (RGC) confirmed the functionality of these sites, showing that MafA binds the predicted sites of CRYGA and CRYGD in HLE and CRYAB, CRYGA, CRYBA1, and CRYBB3 in RGC cells. In the retina there is a highly correlated group of genes containing many members of the α- β- and γ-crystallin families. These genes can be dramatically upregulated in the retina. One transcription factor that appears to be involved in this coordinated expression is the MAF family transcription of factors associated with both lens and extralenticular expression of crystallin genes.
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Affiliation(s)
- Justin P Templeton
- Department of Ophthalmology, University of Tennessee Health Science Center, 930 Madison Av., Suite 731, Memphis, TN 38163, USA
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Crystallins in retinal ganglion cell survival and regeneration. Mol Neurobiol 2013; 48:819-28. [PMID: 23709342 DOI: 10.1007/s12035-013-8470-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 05/06/2013] [Indexed: 12/31/2022]
Abstract
Crystallins are heterogeneous proteins classified into alpha, beta, and gamma families. Although crystallins were first identified as the major structural components of the ocular lens with a principal function to maintain lens transparency, further studies have demonstrated the expression of these proteins in a wide variety of tissues and cell types. Alpha crystallins (alpha A and alpha B) share significant homology with small heat shock proteins and have chaperone-like properties, including the ability to bind and prevent the precipitation of denatured proteins and to increase cellular resistance to stress-induced apoptosis. Stress-induced upregulation of crystallin expression is a commonly observed phenomenon and viewed as a cellular response mechanism against environmental and metabolic insults. However, several studies reported downregulation of crystallin gene expression in various models of glaucomatous nerodegeneration suggesting that that the decreased levels of crystallins may affect the survival properties of retinal ganglion cells (RGCs) and thus, be associated with their degeneration. This hypothesis was corroborated by increased survival of axotomized RGCs in retinas overexpressing alpha A or alpha B crystallins. In addition to RGC protective functions of alpha crystallins, beta and gamma crystallins were implicated in RGC axonal regeneration. These findings demonstrate the importance of crystallin genes in RGC survival and regeneration and further in-depth studies are necessary to better understand the mechanisms underlying the functions of these proteins in healthy RGCs as well as during glaucomatous neurodegeneration, which in turn could help in designing new therapeutic strategies to preserve or regenerate these cells.
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Prokosch V, Schallenberg M, Thanos S. Crystallins are regulated biomarkers for monitoring topical therapy of glaucomatous optic neuropathy. PLoS One 2013; 8:e49730. [PMID: 23468831 PMCID: PMC3582637 DOI: 10.1371/journal.pone.0049730] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 10/17/2012] [Indexed: 11/21/2022] Open
Abstract
Optic nerve atrophy caused by abnormal intraocular pressure (IOP) remains the most common cause of irreversible loss of vision worldwide. The aim of this study was to determine whether topically applied IOP-lowering eye drugs affect retinal ganglion cells (RGCs) and retinal metabolism in a rat model of optic neuropathy. IOP was elevated through cauterization of episcleral veins, and then lowered either by the daily topical application of timolol, timolol/travoprost, timolol/dorzolamide, or timolol/brimonidine, or surgically with sectorial iridectomy. RGCs were retrogradely labeled 4 days prior to enucleation, and counted. Two-dimensional polyacrylamide gel electrophoresis (2D-PAGE), matrix-assisted laser desorption ionization mass spectrometry, Western blotting, and immunohistochemistry allowed the identification of IOP-dependent proteomic changes. Genomic changes were scrutinized using microarrays and qRT-PCR. The significant increase in IOP induced by episcleral vein cauterization that persisted until 8 weeks of follow-up in control animals (p<0.05) was effectively lowered by the eye drops (p<0.05). As anticipated, the number of RGCs decreased significantly following 8 weeks of elevated IOP (p<0.05), while treatment with combination compounds markedly improved RGC survival (p<0.05). 2D-PAGE and Western blot analyses revealed an IOP-dependent expression of crystallin cry-βb2. Microarray and qRT-PCR analyses verified the results at the mRNA level. IHC demonstrated that crystallins were expressed mainly in the ganglion cell layer. The data suggest that IOP and either topically applied antiglaucomatous drugs influence crystallin expression within the retina. Neuronal crystallins are thus suitable biomarkers for monitoring the progression of neuropathy and evaluating any neuroprotective effects.
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Affiliation(s)
- Verena Prokosch
- Institute of Experimental Ophthalmology, School of Medicine, University of Münster, Albert-Schweitzer-Campus 1, Münster, Germany
| | - Maurice Schallenberg
- Institute of Experimental Ophthalmology, School of Medicine, University of Münster, Albert-Schweitzer-Campus 1, Münster, Germany
| | - Solon Thanos
- Institute of Experimental Ophthalmology, School of Medicine, University of Münster, Albert-Schweitzer-Campus 1, Münster, Germany
- Interdisciplinary Center for Clinical Research, Albert-Schweitzer-Campus 1, Münster, Germany
- * E-mail:
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Hamann S, Métrailler S, Schorderet DF, Cottet S. Analysis of the cytoprotective role of α-crystallins in cell survival and implication of the αA-crystallin C-terminal extension domain in preventing Bax-induced apoptosis. PLoS One 2013; 8:e55372. [PMID: 23383327 PMCID: PMC3562314 DOI: 10.1371/journal.pone.0055372] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 12/21/2012] [Indexed: 12/17/2022] Open
Abstract
α-Crystallins, initially described as the major structural proteins of the lens, belong to the small heat shock protein family. Apart from their function as chaperones, α-crystallins are involved in the regulation of intracellular apoptotic signals. αA- and αB-crystallins have been shown to interfere with the mitochondrial apoptotic pathway triggering Bax pro-apoptotic activity and downstream activation of effector caspases. Differential regulation of α-crystallins has been observed in several eye diseases such as age-related macular degeneration and stress-induced and inherited retinal degenerations. Although the function of α-crystallins in healthy and diseased retina remains poorly understood, their altered expression in pathological conditions argue in favor of a role in cellular defensive response. In the Rpe65⁻/⁻ mouse model of Leber's congenital amaurosis, we previously observed decreased expression of αA- and αB-crystallins during disease progression, which was correlated with Bax pro-death activity and photoreceptor apoptosis. In the present study, we demonstrated that α-crystallins interacted with pro-apoptotic Bax and displayed cytoprotective action against Bax-triggered apoptosis, as assessed by TUNEL and caspase assays. We further observed in staurosporine-treated photoreceptor-like 661W cells stably overexpressing αA- or αB-crystallin that Bax-dependent apoptosis and caspase activation were inhibited. Finally, we reported that the C-terminal extension domain of αA-crystallin was sufficient to provide protection against Bax-triggered apoptosis. Altogether, these data suggest that α-crystallins interfere with Bax-induced apoptosis in several cell types, including the cone-derived 661W cells. They further suggest that αA-crystallin-derived peptides might be sufficient to promote cytoprotective action in response to apoptotic cell death.
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Affiliation(s)
- Séverine Hamann
- IRO, Institute for Research in Ophthalmology, Sion, Switzerland
- School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
| | | | - Daniel F. Schorderet
- IRO, Institute for Research in Ophthalmology, Sion, Switzerland
- School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
- Department of Ophthalmology, University of Lausanne, Lausanne, Switzerland
| | - Sandra Cottet
- IRO, Institute for Research in Ophthalmology, Sion, Switzerland
- Department of Ophthalmology, University of Lausanne, Lausanne, Switzerland
- * E-mail:
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Böhm MRR, Melkonyan H, Oellers P, Thanos S. Effects of crystallin-β-b2 on stressed RPE in vitro and in vivo. Graefes Arch Clin Exp Ophthalmol 2012; 251:63-79. [PMID: 23073841 DOI: 10.1007/s00417-012-2157-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 08/25/2012] [Accepted: 09/03/2012] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Crystallins are thought to play a cytoprotective role in conditions of cellular stress. The aim of this study was to determine the effects of crystallin-β-b2 (cryβ-b2) and crystallin-β-b3 (cryβ-b3) on ARPE-19 cells in vitro and on the retinal pigment epithelium (RPE) in vivo. METHODS The influence of cryβ-b2 and cryβ-b3 on the viability, proliferation and dying of ARPE-19 was measured by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium assay, bromo-2-deoxyuridine assay and life/death assay. The expressions of cryβ-b2, cryβ-b3, glial-derived neurotrophic factor (GDNF), and galectin-3 (Gal-3) in ARPE-19 cells were evaluated using immunohistochemistry (IHC), Western blotting (WB) and real-time-quantitative-PCR (qRT-PCR). To evaluate the response of cryβ-b2 and cryβ-b3 to stressed ARPE-19 cells, the cells were exposed to UV-light. In a rat model, cryβ-b2-expressing neural progenitor cells (cryβ-b2-NPCs) were injected intravitreally after retinal stress induced by optic nerve axotomy to examine whether they influence the RPE. Protein expression was examined 2 and 4 weeks postsurgery using IHC and WB. RESULTS Detectable alterations of GDNF, and Gal-3 were found in ARPE-19 cells upon exposure to UV light. Adding the crystallins to the medium promoted proliferation and increased viability of ARPE-19 cells in vitro. The obtained data support the view that these crystallins possess epithelioprotective properties. Likewise, in vivo, intravitreally injected cryβ-b2 and transplanted cryβ-b2-NPCs protected RPE from indirectly induced stress. CONCLUSIONS The data suggest that the RPE response to retinal ganglion cell denegeration is mediated via crystallins, which may thus be used therapeutically.
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Affiliation(s)
- Michael R R Böhm
- Institute of Experimental Ophthalmology, School of Medicine, Westfalian Wilhelms-University Münster, Albert-Schweitzer-Campus 1, D15, 48149 Münster, Germany.
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Kim SJ, Jin J, Kim YJ, Kim Y, Yu HG. Retinal proteome analysis in a mouse model of oxygen-induced retinopathy. J Proteome Res 2012; 11:5186-203. [PMID: 23039900 DOI: 10.1021/pr300389r] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
To identify proteins that are involved in the molecular mechanisms of oxygen-induced retinopathy (OIR), a well-established model of blinding ischemic retinopathy, we quantitatively analyzed the retinal proteome in a mouse model of OIR. OIR was induced by exposing C57BL/6 mice on postnatal day 7 (P7) to 75% hyperoxia for 5 days, followed by 5 days in room air. Retinas from mice on P12 and P17, the hyperoxic and hypoxic phases, respectively, and control groups were examined using isobaric tags for relative and absolute quantitation (iTRAQ) and nano-LC-ESI-MS/MS. In total, 1422 retinal proteins were identified: 699 from the iTRAQ experiment and 1074 by nano-LC-ESI-MS/MS. Compared with control retinas in the iTRAQ study, OIR retinas upregulated and downregulated 21 and 17 proteins, respectively, in P17 retinas and 25 and 14 proteins, respectively, in P12 retinas. Of the differentially expressed proteins, the retinal expression of crystallin proteins, Müller cell-associated proteins, neurodegeneration-associated proteins, and angiogenesis-associated proteins, such as 150-kDa oxygen-regulated protein (ORP150), were analyzed. ORP150 colocalized to the neovascular tufts, and knockdown of ORP150 by siRNA decreased the levels of secreted VEGF in cultured retinal pigment epithelial cells. Moreover, intravitreal administration of siRNA targeting ORP150 significantly reduced the retinal neovascularization in OIR. In conclusion, our proteomic discovery method, coupled with targeted approaches, revealed many proteins that were differentially regulated in the mouse model of OIR. These proteins, including ORP150, are potential novel therapeutic targets for the treatment of proliferative ischemic retinopathy.
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Affiliation(s)
- Sang Jin Kim
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Republic of Korea
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Zheng Q, Ren Y, Tzekov R, Zhang Y, Chen B, Hou J, Zhao C, Zhu J, Zhang Y, Dai X, Ma S, Li J, Pang J, Qu J, Li W. Differential proteomics and functional research following gene therapy in a mouse model of Leber congenital amaurosis. PLoS One 2012; 7:e44855. [PMID: 22953002 PMCID: PMC3432120 DOI: 10.1371/journal.pone.0044855] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 08/08/2012] [Indexed: 11/19/2022] Open
Abstract
Leber congenital amaurosis (LCA) is one of the most severe forms of inherited retinal degeneration and can be caused by mutations in at least 15 different genes. To clarify the proteomic differences in LCA eyes, a cohort of retinal degeneration 12 (rd12) mice, an LCA2 model caused by a mutation in the RPE65 gene, were injected subretinally with an AAV vector (scAAV5-smCBA-hRPE65) in one eye, while the contralateral eye served as a control. Proteomics were compared between untreated rd12 and normal control retinas on P14 and P21, and among treated and untreated rd12 retinas and control retinas on P42. Gene therapy in rd12 mice restored retinal function in treated eyes, which was demonstrated by electroretinography (ERG). Proteomic analysis successfully identified 39 proteins expressed differently among the 3 groups. The expression of 3 proteins involved in regulation of apoptosis and neuroptotection (alpha A crystallin, heat shock protein 70 and peroxiredoxin 6) were investigated further. Immunofluorescence, Western blot and real-time PCR confirmed the quantitative changes in their expression. Furthermore, cell culture studies suggested that peroxiredoxin 6 could act in an antioxidant role in rd12 mice. Our findings support the feasibility of gene therapy in LCA2 patients and support a role for alpha A crystallin, heat shock protein 70 and peroxiredoxin 6 in the pathogenetic mechanisms involved in LCA2 disease process.
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Affiliation(s)
| | - Yueping Ren
- Eye Hospital, Wenzhou Medical College, Wenzhou, China
| | - Radouil Tzekov
- The Roskamp Institute, Sarasota, Florida, United States of America
| | - Yuanping Zhang
- Department of Ophthalmology, The Second Affiliated Hospital of Kunming Medical College, Kunming, China
| | - Bo Chen
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Jiangping Hou
- Eye Hospital, Wenzhou Medical College, Wenzhou, China
| | - Chunhui Zhao
- Eye Hospital, Wenzhou Medical College, Wenzhou, China
| | - Jiali Zhu
- Eye Hospital, Wenzhou Medical College, Wenzhou, China
| | - Ying Zhang
- Eye Hospital, Wenzhou Medical College, Wenzhou, China
| | - Xufeng Dai
- Eye Hospital, Wenzhou Medical College, Wenzhou, China
| | - Shan Ma
- Department of Ophthalmology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Jia Li
- Department of Ophthalmology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Jijing Pang
- Eye Hospital, Wenzhou Medical College, Wenzhou, China
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Jia Qu
- Eye Hospital, Wenzhou Medical College, Wenzhou, China
| | - Wensheng Li
- Eye Hospital, Wenzhou Medical College, Wenzhou, China
- Neurobiology-Neurodegeneration and Repair Laboratory, Retinal Cell Biology and Degeneration Section, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
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Kannan R, Sreekumar PG, Hinton DR. Novel roles for α-crystallins in retinal function and disease. Prog Retin Eye Res 2012; 31:576-604. [PMID: 22721717 DOI: 10.1016/j.preteyeres.2012.06.001] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 05/31/2012] [Accepted: 06/04/2012] [Indexed: 01/18/2023]
Abstract
α-Crystallins are key members of the superfamily of small heat shock proteins that have been studied in detail in the ocular lens. Recently, novel functions for α-crystallins have been identified in the retina and in the retinal pigmented epithelium (RPE). αB-Crystallin has been localized to multiple compartments and organelles including mitochondria, golgi apparatus, endoplasmic reticulum and nucleus. α-Crystallins are regulated by oxidative and endoplasmic reticulum stress, and inhibit apoptosis-induced cell death. α-Crystallins interact with a large number of proteins that include other crystallins, and apoptotic, cytoskeletal, inflammatory, signaling, angiogenic, and growth factor molecules. Studies with RPE from αB-crystallin deficient mice have shown that αB-crystallin supports retinal and choroidal angiogenesis through its interaction with vascular endothelial growth factor. αB-Crystallin has also been shown to have novel functions in the extracellular space. In RPE, αB-crystallin is released from the apical surface in exosomes where it accumulates in the interphotoreceptor matrix and may function to protect neighboring cells. In other systems administration of exogenous recombinant αB-crystallin has been shown to be anti-inflammatory. Another newly described function of αB-crystallin is its ability to inhibit β-amyloid fibril formation. α-Crystallin minichaperone peptides have been identified that elicit anti-apoptotic function in addition to being efficient chaperones. Generation of liposomal particles and other modes of nanoencapsulation of these minipeptides could offer great therapeutic advantage in ocular delivery for a wide variety of retinal degenerative, inflammatory and vascular diseases including age-related macular degeneration and diabetic retinopathy.
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Affiliation(s)
- Ram Kannan
- Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Los Angeles, CA 90033, United States
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Heise EA, Fort PE. Impact of diabetes on alpha-crystallins and other heat shock proteins in the eye. J Ocul Biol Dis Infor 2011; 4:62-9. [PMID: 23264844 DOI: 10.1007/s12177-011-9073-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 12/05/2011] [Indexed: 12/25/2022] Open
Abstract
Diabetes and its related complications represent a major growing health concern and economic burden worldwide. Ocular manifestations of diabetes include cataractogenesis and retinopathy, the latter being the leading cause of blindness in the working-age population. Despite numerous studies and recent progress, the exact pathophysiology of the disease remains to be fully elucidated and development of new and improved therapeutic strategies for this chronic condition are greatly needed. Heat shock proteins (Hsps) are highly conserved families of proteins, which are generally regarded as protective molecules that play a wide variety of roles and can be expressed in response to different types of cellular stresses. In recent years, numerous studies have reported their implication in various ocular diseases including diabetic retinopathy. The present review focuses on the potential implication of Hsps in ocular diabetic complications and discusses their specific mechanisms of regulation with respect to their expression, functions and alteration during diabetes. The review will conclude by examining the potential of Hsps as therapeutic agents or targets for the treatment of diabetic retinopathy.
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Affiliation(s)
- Erich A Heise
- Kellogg Eye Center, Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI USA
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35
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Functional rescue of experimental ischemic optic neuropathy with αB-crystallin. Eye (Lond) 2011; 25:809-17. [PMID: 21475310 DOI: 10.1038/eye.2011.42] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
PURPOSE Anterior ischemic optic neuropathy (AION) is an important cause of acute vision loss in adults, and there is no effective treatment. We studied early changes following experimental AION and tested the benefit of a potential treatment. MATERIALS AND METHODS We induced experimental AION in adult mice and tested the effects of short-term (daily for 3 days) and long-term (every other day for 3 weeks) αB-crystallin (αBC) treatment using histological and serial intracranial flash visual evoked potential recordings. RESULTS One day after experimental AION, there was swelling at the optic nerve (ON) head and increased expression of αBC, a small heat shock protein important in ischemia and inflammation. This upregulation coincided with microglial and astrocytic activation. Our hypothesis was that αBC may be part of the endogenous protective mechanism against injury, thus we tested the effects of αBC on experimental AION. Daily intraveneous or intravitreal αBC injections did not improve visual evoked potential amplitude or latency at days 1-2. However, αBC treatment decreased swelling and dampened the microglial and astrocytic activation on day 3. Longer treatment with intravenous αBC led to acceleration of visual evoked potential latency over 3 weeks, without improving amplitude. This latency acceleration did not correlate with increased retinal ganglion cell survival but did correlate with complete rescue of the ON oligodendrocytes, which are important for myelination. CONCLUSIONS We identified αBC as an early marker following experimental AION. Treatment with αBC enhanced this endogenous, post-ischemic response by decreasing microglial activation and promoting ON oligodendrocyte survival.
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Gangalum RK, Atanasov IC, Zhou ZH, Bhat SP. AlphaB-crystallin is found in detergent-resistant membrane microdomains and is secreted via exosomes from human retinal pigment epithelial cells. J Biol Chem 2011; 286:3261-9. [PMID: 21097504 PMCID: PMC3030331 DOI: 10.1074/jbc.m110.160135] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 11/15/2010] [Indexed: 12/22/2022] Open
Abstract
αB-crystallin (αB) is known as an intracellular Golgi membrane-associated small heat shock protein. Elevated levels of this protein have been linked with a myriad of neurodegenerative pathologies including Alzheimer disease, multiple sclerosis, and age-related macular degeneration. The membrane association of αB has been known for more than 3 decades, yet its physiological import has remained unexplained. In this investigation we show that αB is secreted from human adult retinal pigment epithelial cells via microvesicles (exosomes), independent of the endoplasmic reticulum-Golgi protein export pathway. The presence of αB in these lipoprotein structures was confirmed by its susceptibility to digestion by proteinase K only when exosomes were exposed to Triton X-100. Transmission electron microscopy was used to localize αB in immunogold-labeled intact and permeabilized microvesicles. The saucer-shaped exosomes, with a median diameter of 100-200 nm, were characterized by the presence of flotillin-1, α-enolase, and Hsp70, the same proteins that associate with detergent-resistant membrane microdomains (DRMs), which are known to be involved in their biogenesis. Notably, using polarized adult retinal pigment epithelial cells, we show that the secretion of αB is predominantly apical. Using OptiPrep gradients we demonstrate that αB resides in the DRM fraction. The secretion of αB is inhibited by the cholesterol-depleting drug, methyl β-cyclodextrin, suggesting that the physiological function of this protein and the regulation of its export through exosomes may reside in its association with DRMs/lipid rafts.
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Affiliation(s)
| | | | - Z. Hong Zhou
- the California NanoSystems Institute, and
- the Department of Microbiology, Immunology, and Molecular Genetics, UCLA, Los Angeles, California 90095
| | - Suraj P. Bhat
- From the Jules Stein Eye Institute
- the Geffen School of Medicine, Brain Research Institute and Molecular Biology Institute
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New focus on alpha-crystallins in retinal neurodegenerative diseases. Exp Eye Res 2010; 92:98-103. [PMID: 21115004 DOI: 10.1016/j.exer.2010.11.008] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 11/08/2010] [Accepted: 11/17/2010] [Indexed: 12/31/2022]
Abstract
The crystallin proteins were initially identified as structural proteins of the ocular lens and have been recently demonstrated to be expressed in normal retina. They are dramatically upregulated by a large range of retinal diseases including diabetic retinopathy, age-related macular degeneration, uveitis, trauma and ischemia. The crystallin family of proteins is composed of alpha-, beta- and gamma-crystallin. Alpha-crystallins, which are small heat shock proteins, have received substantial attention recently. This review summarizes the current knowledge of alpha-crystallins in retinal diseases, their roles in retinal neuron cell survival and retinal inflammation, and the regulation of their expression and activity. Their potential role in the development of new treatments for neurodegenerative diseases is also discussed.
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Organisciak D, Darrow R, Barsalou L, Rapp C, McDonald B, Wong P. Light induced and circadian effects on retinal photoreceptor cell crystallins. Photochem Photobiol 2010; 87:151-9. [PMID: 21091955 DOI: 10.1111/j.1751-1097.2010.00844.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Crystallins in the retina may serve a chaperone-like protective function. In this study we measured mRNA levels for alpha-, beta- and gamma-crystallins in rat retinas following treatment with potentially damaging levels of light. We also determined crystallin protein patterns in photoreceptor cell rod outer segments (ROSs) isolated from rats exposed to intense light. Weanling albino rats were maintained in a dim cyclic light environment or in darkness for 40days. At P60 animals were treated with intense visible light, for as long as 8h, beginning at various times of the day or night. Retinas were excised immediately after light treatment and used for quantitative RT-PCR, or to prepare ROSs for western analysis. Some eyes were frozen in OCT for crystallin immunohistochemistry. Intense light exposure led to increases in mRNA expression for all retinal crystallins and to changes in ROS crystallin immunoreactivity. These light-induced changes were found to depend on the time of day that exposure started, duration of light treatment and previous light rearing history. We suggest that crystallin synthesis in retina exhibits a dependence on both light stress and circadian rhythm and that within photoreceptor cells crystallins appear to migrate in a light-independent, circadian fashion.
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Affiliation(s)
- Daniel Organisciak
- Petticrew Research Laboratory, Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine Wright State University, Dayton, OH, USA.
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Lee H, Chung H, Lee SH, Jahng WJ. Light-induced phosphorylation of crystallins in the retinal pigment epithelium. Int J Biol Macromol 2010; 48:194-201. [PMID: 21094180 DOI: 10.1016/j.ijbiomac.2010.11.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Revised: 11/08/2010] [Accepted: 11/09/2010] [Indexed: 10/18/2022]
Abstract
Protein phosphorylations have essential regulatory roles in visual signaling. Previously, we found that phosphorylation of several proteins in the retina and retinal pigment epithelium (RPE) is involved in anti-apoptotic signaling under oxidative stress conditions, including light exposure. In this study, we used a phosphoprotein enrichment strategy to evaluate the light-induced phosphoproteome of primary bovine RPE cells. Phosphoprotein-enriched extracts from bovine RPE cells exposed to light or dark conditions for 1h were separated by 2D SDS-PAGE. Serine and tyrosine phosphorylations were visualized by 2D phospho Western blotting and specific phosphorylation sites were analyzed by tandem mass spectrometry. Light induced a marked increase in tyrosine phosphorylation of beta crystallin A3 and A4. The most abundant light-induced up-regulated phosphoproteins were crystallins of 15-25 kDa, including beta crystallin S and zeta crystallin. Phosphorylation of beta crystallin suggests an anti-apoptotic chaperone function of crystallins in the RPE. Other chaperones, cytoskeletal proteins, and proteins involved in energy balance were expressed at higher levels in the dark. A detailed analysis of RPE phosphoproteins provides a molecular basis for understanding of light-induced signal transduction and anti-apoptosis mechanisms. Our data indicates that phosphorylation of crystallins likely represents an important mechanism for RPE shielding from physiological and pathophysiological light-induced oxidative injury.
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Affiliation(s)
- Hyunju Lee
- Department of Ophthalmology, University of South Carolina, Columbia, SC 29208, USA
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Sturgill GM, Bala E, Yaniglos SS, Peachey NS, Hagstrom SA. Mutation screen of beta-crystallin genes in 274 patients with age-related macular degeneration. Ophthalmic Genet 2010; 31:129-34. [PMID: 20565250 DOI: 10.3109/13816810.2010.486774] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE The crystallin family of proteins comprise the main structural proteins of the vertebrate lens and have been classified into alpha-, beta-, and gamma- families. Several of the beta-crystallin proteins have been detected in the retina where they are each localized to different compartments of rod and cone photoreceptors. Functionally, beta-crystallins have been implicated in the protection of the retina from intense light exposure. Two members of the beta-crystallins, CRYBB1 and CRYBB2, have been identified in drusen preparations isolated from the retina of donor eyes of patients with age-related macular degeneration (AMD), the leading cause of blindness in the elderly population of developed countries. We therefore investigated CRYBB1 and CRYBB2 as candidate genes for AMD in 274 unrelated patients. RESULTS A mutation screen of the entire coding region of the CRYBB1gene uncovered eight sequence variations, including three missense changes, two intronic changes and three isocoding changes. A mutation screen of the entire coding region of the CRYBB2 gene uncovered three sequence variations, one isocoding change and two intronic changes. CONCLUSIONS Although variant alleles of the CRYBB1 and CRYBB2 genes were found, none are considered pathogenic.
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Affiliation(s)
- Gwen M Sturgill
- Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio, USA
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αB crystallin is apically secreted within exosomes by polarized human retinal pigment epithelium and provides neuroprotection to adjacent cells. PLoS One 2010; 5:e12578. [PMID: 20949024 PMCID: PMC2951891 DOI: 10.1371/journal.pone.0012578] [Citation(s) in RCA: 162] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Accepted: 08/08/2010] [Indexed: 12/20/2022] Open
Abstract
αB Crystallin is a chaperone protein with anti-apoptotic and anti-inflammatory functions and has been identified as a biomarker in age-related macular degeneration. The purpose of this study was to determine whether αB crystallin is secreted from retinal pigment epithelial (RPE) cells, the mechanism of this secretory pathway and to determine whether extracellular αB crystallin can be taken up by adjacent retinal cells and provide protection from oxidant stress. We used human RPE cells to establish that αB crystallin is secreted by a non-classical pathway that involves exosomes. Evidence for the release of exosomes by RPE and localization of αB crystallin within the exosomes was achieved by immunoblot, immunofluorescence, and electron microscopic analyses. Inhibition of lipid rafts or exosomes significantly reduced αB crystallin secretion, while inhibitors of classic secretory pathways had no effect. In highly polarized RPE monolayers, αB crystallin was selectively secreted towards the apical, photoreceptor-facing side. In support, confocal microscopy established that αB crystallin was localized predominantly in the apical compartment of RPE monolayers, where it co-localized in part with exosomal marker CD63. Severe oxidative stress resulted in barrier breakdown and release of αB crystallin to the basolateral side. In normal mouse retinal sections, αB crystallin was identified in the interphotoreceptor matrix. An increased uptake of exogenous αB crystallin and protection from apoptosis by inhibition of caspase 3 and PARP activation were observed in stressed RPE cultures. αB Crystallin was taken up by photoreceptors in mouse retinal explants exposed to oxidative stress. These results demonstrate an important role for αB crystallin in maintaining and facilitating a neuroprotective outer retinal environment and may also explain the accumulation of αB crystallin in extracellular sub-RPE deposits in the stressed microenvironment in age-related macular degeneration. Thus evidence from our studies supports a neuroprotective role for αB crystallin in ocular diseases.
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Chiu K, Zhou Y, Yeung SC, Lok CKM, Chan OOC, Chang RCC, So KF, Chiu JF. Up-regulation of crystallins is involved in the neuroprotective effect of wolfberry on survival of retinal ganglion cells in rat ocular hypertension model. J Cell Biochem 2010; 110:311-20. [PMID: 20336662 DOI: 10.1002/jcb.22539] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Wolfberry (fruit of Lycium barbarum Linn) has been known for balancing 'Yin' and 'Yang' in the body, nourishing the liver and kidney, improving visual acuity for more than 2,500 years in oriental countries. The active components in wolfberry include L. barbarum polysaccharide (LBP), zeaxanthine, betaine, cerebroside and trace amounts of zinc, iron, and copper. Each of them confers distinct beneficial effects and together they help to explain widespread use of wolfberry in the eastern world. Earlier study reported the neuroprotective effects of LBP on retinal ganglion cell (RGC) in an experimental model of glaucoma and the underlying in vivo cellular mechanisms of LBP neuroprotection deserve further exploration. In this study, we adopted proteomics, functional genomics, to evaluate pharmacological effects of LBP on the neuronal survival pathways. Among the significantly changed proteins induced by LBP feeding on ocular hypertension (OH) retinas, only proteins in crystallin family were focused in this study. The proteomic results were further confirmed using the Western blotting of the retinas and immunohistochemical staining of the retinal sections. We demonstrated that neuroprotective effect of-wolfberry extract-LBP on the survival of RGCs may be mediated via direct up-regulation of neuronal survival signal betaB2-crystallin.
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Affiliation(s)
- Kin Chiu
- Laboratory of Neurodegenerative Diseases, Department of Anatomy, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
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Ashby RS, Megaw PL, Morgan IG. Changes in retinal alphaB-crystallin (cryab) RNA transcript levels during periods of altered ocular growth in chickens. Exp Eye Res 2009; 90:238-43. [PMID: 19878675 DOI: 10.1016/j.exer.2009.10.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 09/29/2009] [Accepted: 10/15/2009] [Indexed: 12/20/2022]
Abstract
Changes in retinal crystallin gene expression have been implicated in the development of myopia in animal models. We therefore investigated the expression of alphaB-crystallin (cryab) in the chicken retina during periods of increased ocular growth induced by form-deprivation and negative lens-wear, and during periods of decreased ocular growth induced by diffuser removal from previously form-deprived eyes, and plus lens-wear. Cryab RNA transcript levels in the chicken retina were measured using semi-quantitative real-time RT-PCR, at times between 1 h and 10 days after the fitting of diffusers or negative lenses, and at times between 1 h and 3 days following the removal of diffusers from previously form-deprived eyes, or the addition of plus lenses. Changes in expression for each condition at each time-point are analysed relative to expression in retinas from age-matched untreated control birds. No change in relative expression of cryab RNA transcript was detected 1 h after fitting diffusers to induce form-deprivation myopia. A transient increase in cryab RNA transcript expression was detected around 1 day later (p = 0.02), but expression returned to control levels after three days. After 7 (p = 0.005) and 10 (p = 0.001) days, retinal cryab RNA transcript expression progressively increased relative to controls. After removal of the diffusers, to initiate recovery, cryab RNA transcript expression remained elevated, with only a slight return to control levels. During the development of lens-induced myopia, no changes in cryab RNA transcript expression relative to controls were seen on day 1, but increases were seen at 10 days (p = 0.004). No significant changes in retinal cryab RNA transcript expression were seen in response to plus lenses compared to either contralateral control values (MANOVA; F = 0.60, p = 0.48) or age-matched untreated values (MANOVA; F = 4.10, p = 0.08). Changes in retinal cryab RNA transcript expression were not systematically related to changes in the rate of eye growth. The role of the transient increase in cryab expression observed after 1 day of form-deprivation, which was not seen after fitting negative lenses, is unclear. The later increases in relative cryab expression seen during the development of form-deprivation and lens-induced myopia occur too late to have a major role in the differential regulation of eye growth between experimental and control eyes. Given that cryab is a member of the small heat shock protein family, the later increases may reflect the emergence of cell damage related to high myopic pathology in the experimentally enlarged eyes and retina.
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Affiliation(s)
- Regan S Ashby
- Visual Sciences Group, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
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44
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Templeton JP, Nassr M, Vazquez-Chona F, Freeman-Anderson NE, Orr WE, Williams RW, Geisert EE. Differential response of C57BL/6J mouse and DBA/2J mouse to optic nerve crush. BMC Neurosci 2009; 10:90. [PMID: 19643015 PMCID: PMC2727955 DOI: 10.1186/1471-2202-10-90] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Accepted: 07/30/2009] [Indexed: 01/02/2023] Open
Abstract
Background Retinal ganglion cell (RGC) death is the final consequence of many blinding diseases, where there is considerable variation in the time course and severity of RGC loss. Indeed, this process appears to be influenced by a wide variety of genetic and environmental factors. In this study we explored the genetic basis for differences in ganglion cell death in two inbred strains of mice. Results We found that RGCs are more susceptible to death following optic nerve crush in C57BL/6J mice (54% survival) than in DBA/2J mice (62% survival). Using the Illumina Mouse-6 microarray, we identified 1,580 genes with significant change in expression following optic nerve crush in these two strains of mice. Our analysis of the changes occurring after optic nerve crush demonstrated that the greatest amount of change (44% of the variance) was due to the injury itself. This included changes associated with ganglion cell death, reactive gliosis, and abortive regeneration. The second pattern of gene changes (23% of the variance) was primarily related to differences in gene expressions observed between the C57BL/6J and DBA/2J mouse strains. The remaining changes in gene expression represent interactions between the effects of optic nerve crush and the genetic background of the mouse. We extracted one genetic network from this dataset that appears to be related to tissue remodeling. One of the most intriguing sets of changes included members of the crystallin family of genes, which may represent a signature of pathways modulating the susceptibility of cells to death. Conclusion Differential responses to optic nerve crush between two widely used strains of mice were used to define molecular networks associated with ganglion cell death and reactive gliosis. These results form the basis for our continuing interest in the modifiers of retinal injury.
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Affiliation(s)
- Justin P Templeton
- Department of Ophthalmology, University of Tennessee Health Science Center, Memphis TN, 38163, USA.
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Kang KH, Lemke G, Kim JW. The PI3K-PTEN tug-of-war, oxidative stress and retinal degeneration. Trends Mol Med 2009; 15:191-8. [PMID: 19380252 DOI: 10.1016/j.molmed.2009.03.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Revised: 03/06/2009] [Accepted: 03/06/2009] [Indexed: 01/01/2023]
Abstract
The retinal pigment epithelium (RPE) is indispensable for photoreceptor function, not only because it provides functional photopigments to photoreceptors, but also because it eliminates oxidatively damaged materials from photoreceptors. Maintaining homeostatic antioxidative programs that support a healthy RPE is therefore important for the normal functioning of the eye. These homeostatic mechanisms, however, often fail in aged RPE cells that have been exposed repeatedly to excessive oxidative stress. When RPE cells succumb to oxidative stress, their death contributes to the development of retinal degenerative diseases such as age-related macular degeneration. Recent studies have highlighted the importance of reciprocal phosphoinositide signaling events orchestrated by phosphoinositide 3-kinase (PI3K) and phosphatase and tensin homolog (PTEN) in the homeostatic programs that protect RPE cells against oxidative stress. Here, we discuss the role of PI3K signaling pathways in RPE cells and suggest that they might be crucial targets of oxidative molecules that initiate early pathological events in retinal degenerative diseases.
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Affiliation(s)
- Kyung Hwa Kang
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 335 Gwahangno, Yuseong-gu, Daejeon 305-701, South Korea
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Krishnan J, Chen J, Shin KJ, Hwang JI, Han SU, Lee G, Choi S. Gene expression profiling of light-induced retinal degeneration in phototransduction gene knockout mice. Exp Mol Med 2009; 40:495-504. [PMID: 18985007 DOI: 10.3858/emm.2008.40.5.495] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Exposure to light can induce photoreceptor cell death and exacerbate retinal degeneration. In this study, mice with genetic knockout of several genes, including rhodopsin kinase (Rhok-/-), arrestin (Sag-/-), transducin (Gnat1-/-), c-Fos (c-Fos-/-) and arrestin/transducin (Sag-/-/Gnat1-/-), were examined. We measured the expression levels of thousands of genes in order to investigate their roles in phototransduction signaling in light-induced retinal degeneration using DNA microarray technology and then further explored the gene network using pathway analysis tools. Several cascades of gene components were induced or inhibited as a result of corresponding gene knockout under specific light conditions. Transducin deletion blocked the apoptotic signaling induced by exposure to low light conditions, and it did not require c-Fos/AP-1. Deletion of c-Fos blocked the apoptotic signaling induced by exposure to high intensity light. In the present study, we identified many gene transcripts that are essential for the initiation of light-induced rod degeneration and proposed several important networks that are involved in pro- and anti-apoptotic signaling. We also demonstrated the different cascades of gene components that participate in apoptotic signaling under specific light conditions.
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Affiliation(s)
- Jayalakshmi Krishnan
- Department of Molecular Science and Technology, Ajou University, Suwon 443-749, Korea
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Fort PE, Freeman WM, Losiewicz MK, Singh RSJ, Gardner TW. The retinal proteome in experimental diabetic retinopathy: up-regulation of crystallins and reversal by systemic and periocular insulin. Mol Cell Proteomics 2008; 8:767-79. [PMID: 19049959 DOI: 10.1074/mcp.m800326-mcp200] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Diabetic retinopathy is the leading cause of blindness in working age persons. Targeted studies have uncovered several components of the pathophysiology of the disease without unveiling the basic mechanisms. This study describes the use of complementary proteomic and genomic discovery methods that revealed that the proteins of the crystallin superfamily are increased dramatically in early diabetic retinopathy. Orthogonal methods confirmed that the amplitude of the up-regulation is greater than other changes described so far in diabetic retinopathy. A detailed time course study during diabetes showed differential up-regulation of the different isoforms of the crystallins superfamily. alpha- and beta-crystallins were regulated primarily at the translation level, whereas gamma-crystallins were also regulated transcriptionally. We also demonstrated cell-specific patterns of expression of the different crystallins in normal and diabetic rat retinas. In addition, systemic and periocular insulin treatments restored retinal crystallin protein expression during diabetes, indicating effects of phosphoinositide 3-kinase/Akt activity. Altogether this work shows the importance of proteomics discovery methods coupled with targeted approaches to unveil new disease mechanistic details and therapeutic targets.
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Affiliation(s)
- Patrice E Fort
- Department of Ophthalmology, Penn State College of Medicine, Hershey, Pennsylvania 17033, USA
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Cottet S, Schorderet DF. Triggering of Bcl-2-related pathway is associated with apoptosis of photoreceptors in Rpe65-/- mouse model of Leber's congenital amaurosis. Apoptosis 2008; 13:329-42. [PMID: 18274907 DOI: 10.1007/s10495-008-0180-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Mutations in RPE65 protein is characterized by the loss of photoreceptors, although the molecular pathways triggering retinal cell death remain largely unresolved. The role of the Bcl-2 family of proteins in retinal degeneration is still controversial. However, alteration in Bcl-2-related proteins has been observed in several models of retinal injury. In particular, Bax has been suggested to play a crucial role in apoptotic pathways in murine glaucoma model as well as in retinal detachment-associated cell death. We demonstrated that Bcl-2-related signaling pathway is involved in Rpe65-dependent apoptosis of photoreceptors during development of the disease. Pro-apoptotic Bax alpha and beta isoforms were upregulated in diseased retina. This was associated with a progressive reduction of anti-apoptotic Bcl-2, reflecting imbalanced Bcl-2/Bax ratio as the disease progresses. Moreover, specific translocation of Bax beta from cytosol to mitochondria was observed in Rpe65-deficient retina. This correlated with the initiation of photoreceptor cell loss at 4 months of age, and further increased during disease development. Altogether, these data suggest that Bcl-2-apoptotic pathway plays a crucial role in Leber's congenital amaurosis disease. They further highlight a new regulatory mechanism of Bax-dependent apoptosis based on regulated expression and activation of specific isoforms of this protein.
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Affiliation(s)
- Sandra Cottet
- Institute for Research in Ophthalmology (IRO), Avenue Grand-Champsec 64, 1950, Sion 4, Switzerland.
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Lam TC, Chun RKM, Li KK, To CH. Application of proteomic technology in eye research: a mini review. Clin Exp Optom 2008; 91:23-33. [PMID: 18045249 DOI: 10.1111/j.1444-0938.2007.00194.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Proteomics is a rapidly growing research area for the study of the protein cognate of genomic data. This review gives a brief overview of the modern proteomic technology. In addition to general applications of proteomics, we highlight its contribution to studying the physiology of different ocular tissues. We also summarise the published proteomic literature in the broad context of ophthalmic diseases, such as cataract, age-related maculopathy, diabetic retinopathy, glaucoma and myopia. The proteomic technology is a useful research tool and it will continue to advance our understanding of a variety of molecular processes in ocular tissues and diseases.
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Affiliation(s)
- Thomas C Lam
- Laboratory of Experimental Optometry, Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong SAR, China
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50
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Sinha D, Klise A, Sergeev Y, Hose S, Bhutto IA, Hackler L, Malpic-Llanos T, Samtani S, Grebe R, Goldberg MF, Hejtmancik JF, Nath A, Zack DJ, Fariss RN, McLeod DS, Sundin O, Broman KW, Lutty GA, Zigler JS. betaA3/A1-crystallin in astroglial cells regulates retinal vascular remodeling during development. Mol Cell Neurosci 2007; 37:85-95. [PMID: 17931883 DOI: 10.1016/j.mcn.2007.08.016] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2007] [Accepted: 08/24/2007] [Indexed: 11/25/2022] Open
Abstract
Vascular remodeling is a complex process critical to development of the mature vascular system. Astrocytes are known to be indispensable for initial formation of the retinal vasculature; our studies with the Nuc1 rat provide novel evidence that these cells are also essential in the retinal vascular remodeling process. Nuc1 is a spontaneous mutation in the Sprague-Dawley rat originally characterized by nuclear cataracts in the heterozygote and microphthalmia in the homozygote. We report here that the Nuc1 allele results from mutation of the betaA3/A1-crystallin gene, which in the neural retina is expressed only in astrocytes. We demonstrate striking structural abnormalities in Nuc1 astrocytes with profound effects on the organization of intermediate filaments. While vessels form in the Nuc1 retina, the subsequent remodeling process required to provide a mature vascular network is deficient. Our data implicate betaA3/A1-crystallin as an important regulatory factor mediating vascular patterning and remodeling in the retina.
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Affiliation(s)
- Debasish Sinha
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Bunting-Blaustein Cancer Research Building II, 1550 Orleans St., Room 146, Baltimore, MD 21231, USA.
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