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Harju N. Regulation of oxidative stress and inflammatory responses in human retinal pigment epithelial cells. Acta Ophthalmol 2022; 100 Suppl 273:3-59. [DOI: 10.1111/aos.15275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Niina Harju
- School of Pharmacy University of Eastern Finland Kuopio Finland
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Bilbao-Malavé V, González-Zamora J, de la Puente M, Recalde S, Fernandez-Robredo P, Hernandez M, Layana AG, Saenz de Viteri M. Mitochondrial Dysfunction and Endoplasmic Reticulum Stress in Age Related Macular Degeneration, Role in Pathophysiology, and Possible New Therapeutic Strategies. Antioxidants (Basel) 2021; 10:antiox10081170. [PMID: 34439418 PMCID: PMC8388889 DOI: 10.3390/antiox10081170] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/14/2021] [Accepted: 07/20/2021] [Indexed: 02/07/2023] Open
Abstract
Age related macular degeneration (AMD) is the main cause of legal blindness in developed countries. It is a multifactorial disease in which a combination of genetic and environmental factors contributes to increased risk of developing this vision-incapacitating condition. Oxidative stress plays a central role in the pathophysiology of AMD and recent publications have highlighted the importance of mitochondrial dysfunction and endoplasmic reticulum stress in this disease. Although treatment with vascular endothelium growth factor inhibitors have decreased the risk of blindness in patients with the exudative form of AMD, the search for new therapeutic options continues to prevent the loss of photoreceptors and retinal pigment epithelium cells, characteristic of late stage AMD. In this review, we explain how mitochondrial dysfunction and endoplasmic reticulum stress participate in AMD pathogenesis. We also discuss a role of several antioxidants (bile acids, resveratrol, melatonin, humanin, and coenzyme Q10) in amelioration of AMD pathology.
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Affiliation(s)
- Valentina Bilbao-Malavé
- Department of Opthalmology, Clínica Universidad de Navarra, 31008 Pamplona, Spain; (V.B.-M.); (J.G.-Z.); (M.d.l.P.); (A.G.L.)
| | - Jorge González-Zamora
- Department of Opthalmology, Clínica Universidad de Navarra, 31008 Pamplona, Spain; (V.B.-M.); (J.G.-Z.); (M.d.l.P.); (A.G.L.)
| | - Miriam de la Puente
- Department of Opthalmology, Clínica Universidad de Navarra, 31008 Pamplona, Spain; (V.B.-M.); (J.G.-Z.); (M.d.l.P.); (A.G.L.)
| | - Sergio Recalde
- Retinal Pathologies and New Therapies Group, Experimental Ophthalmology Laboratory, Department of Ophthalmology, Universidad de Navarra, 31008 Pamplona, Spain; (S.R.); (P.F.-R.); (M.H.)
- Navarra Institute for Health Research, IdiSNA, 31008 Pamplona, Spain
- Red Temática de Investigación Cooperativa en Salud: ‘Prevention, Early Detection, and Treatment of the Prevalent Degenerative and Chronic Ocular Pathology’ from (RD16/0008/0011), Ministerio de Ciencia, Innovación y Universidades, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Patricia Fernandez-Robredo
- Retinal Pathologies and New Therapies Group, Experimental Ophthalmology Laboratory, Department of Ophthalmology, Universidad de Navarra, 31008 Pamplona, Spain; (S.R.); (P.F.-R.); (M.H.)
- Navarra Institute for Health Research, IdiSNA, 31008 Pamplona, Spain
- Red Temática de Investigación Cooperativa en Salud: ‘Prevention, Early Detection, and Treatment of the Prevalent Degenerative and Chronic Ocular Pathology’ from (RD16/0008/0011), Ministerio de Ciencia, Innovación y Universidades, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - María Hernandez
- Retinal Pathologies and New Therapies Group, Experimental Ophthalmology Laboratory, Department of Ophthalmology, Universidad de Navarra, 31008 Pamplona, Spain; (S.R.); (P.F.-R.); (M.H.)
- Navarra Institute for Health Research, IdiSNA, 31008 Pamplona, Spain
- Red Temática de Investigación Cooperativa en Salud: ‘Prevention, Early Detection, and Treatment of the Prevalent Degenerative and Chronic Ocular Pathology’ from (RD16/0008/0011), Ministerio de Ciencia, Innovación y Universidades, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Alfredo Garcia Layana
- Department of Opthalmology, Clínica Universidad de Navarra, 31008 Pamplona, Spain; (V.B.-M.); (J.G.-Z.); (M.d.l.P.); (A.G.L.)
- Retinal Pathologies and New Therapies Group, Experimental Ophthalmology Laboratory, Department of Ophthalmology, Universidad de Navarra, 31008 Pamplona, Spain; (S.R.); (P.F.-R.); (M.H.)
- Navarra Institute for Health Research, IdiSNA, 31008 Pamplona, Spain
- Red Temática de Investigación Cooperativa en Salud: ‘Prevention, Early Detection, and Treatment of the Prevalent Degenerative and Chronic Ocular Pathology’ from (RD16/0008/0011), Ministerio de Ciencia, Innovación y Universidades, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Manuel Saenz de Viteri
- Department of Opthalmology, Clínica Universidad de Navarra, 31008 Pamplona, Spain; (V.B.-M.); (J.G.-Z.); (M.d.l.P.); (A.G.L.)
- Retinal Pathologies and New Therapies Group, Experimental Ophthalmology Laboratory, Department of Ophthalmology, Universidad de Navarra, 31008 Pamplona, Spain; (S.R.); (P.F.-R.); (M.H.)
- Navarra Institute for Health Research, IdiSNA, 31008 Pamplona, Spain
- Red Temática de Investigación Cooperativa en Salud: ‘Prevention, Early Detection, and Treatment of the Prevalent Degenerative and Chronic Ocular Pathology’ from (RD16/0008/0011), Ministerio de Ciencia, Innovación y Universidades, Instituto de Salud Carlos III, 28029 Madrid, Spain
- Correspondence: ; Tel.: +34-948-255-400
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Campello L, Singh N, Advani J, Mondal AK, Corso-Diaz X, Swaroop A. Aging of the Retina: Molecular and Metabolic Turbulences and Potential Interventions. Annu Rev Vis Sci 2021; 7:633-664. [PMID: 34061570 DOI: 10.1146/annurev-vision-100419-114940] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Multifaceted and divergent manifestations across tissues and cell types have curtailed advances in deciphering the cellular events that accompany advanced age and contribute to morbidities and mortalities. Increase in human lifespan during the past century has heightened awareness of the need to prevent age-associated frailty of neuronal and sensory systems to allow a healthy and productive life. In this review, we discuss molecular and physiological attributes of aging of the retina, with a goal of understanding age-related impairment of visual function. We highlight the epigenome-metabolism nexus and proteostasis as key contributors to retinal aging and discuss lifestyle changes as potential modulators of retinal function. Finally, we deliberate promising intervention strategies for promoting healthy aging of the retina for improved vision. Expected final online publication date for the Annual Review of Vision Science, Volume 7 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Laura Campello
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Nivedita Singh
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Jayshree Advani
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Anupam K Mondal
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Ximena Corso-Diaz
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Anand Swaroop
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;
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A Re-Appraisal of Pathogenic Mechanisms Bridging Wet and Dry Age-Related Macular Degeneration Leads to Reconsider a Role for Phytochemicals. Int J Mol Sci 2020; 21:ijms21155563. [PMID: 32756487 PMCID: PMC7432893 DOI: 10.3390/ijms21155563] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 07/31/2020] [Accepted: 08/01/2020] [Indexed: 12/14/2022] Open
Abstract
Which pathogenic mechanisms underlie age-related macular degeneration (AMD)? Are they different for dry and wet variants, or do they stem from common metabolic alterations? Where shall we look for altered metabolism? Is it the inner choroid, or is it rather the choroid–retinal border? Again, since cell-clearing pathways are crucial to degrade altered proteins, which metabolic system is likely to be the most implicated, and in which cell type? Here we describe the unique clearing activity of the retinal pigment epithelium (RPE) and the relevant role of its autophagy machinery in removing altered debris, thus centering the RPE in the pathogenesis of AMD. The cell-clearing systems within the RPE may act as a kernel to regulate the redox homeostasis and the traffic of multiple proteins and organelles toward either the choroid border or the outer segments of photoreceptors. This is expected to cope with the polarity of various domains within RPE cells, with each one owning a specific metabolic activity. A defective clearance machinery may trigger unconventional solutions to avoid intracellular substrates’ accumulation through unconventional secretions. These components may be deposited between the RPE and Bruch’s membrane, thus generating the drusen, which remains the classic hallmark of AMD. These deposits may rather represent a witness of an abnormal RPE metabolism than a real pathogenic component. The empowerment of cell clearance, antioxidant, anti-inflammatory, and anti-angiogenic activity of the RPE by specific phytochemicals is here discussed.
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Pomatto LCD, Davies KJA. Adaptive homeostasis and the free radical theory of ageing. Free Radic Biol Med 2018; 124:420-430. [PMID: 29960100 PMCID: PMC6098721 DOI: 10.1016/j.freeradbiomed.2018.06.016] [Citation(s) in RCA: 114] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 06/01/2018] [Accepted: 06/14/2018] [Indexed: 01/18/2023]
Abstract
The Free Radical Theory of Ageing, was first proposed by Denham Harman in the mid-1950's, based largely on work conducted by Rebeca Gerschman and Daniel Gilbert. At its core, the Free Radical Theory of Ageing posits that free radical and related oxidants, from the environment and internal metabolism, cause damage to cellular constituents that, over time, result in an accumulation of structural and functional problems. Several variations on the original concept have been advanced over the past six decades, including the suggestion of a central role for mitochondria-derived reactive species, and the proposal of an age-related decline in the effectiveness of protein, lipid, and DNA repair systems. Such innovations have helped the Free Radical Theory of Aging to achieve widespread popularity. Nevertheless, an ever-growing number of apparent 'exceptions' to the Theory have seriously undermined its acceptance. In part, we suggest, this has resulted from a rather simplistic experimental approach of knocking-out, knocking-down, knocking-in, or overexpressing antioxidant-related genes to determine effects on lifespan. In some cases such experiments have yielded results that appear to support the Free Radical Theory of Aging, but there are just as many published papers that appear to contradict the Theory. We suggest that free radicals and related oxidants are but one subset of stressors with which all life forms must cope over their lifespans. Adaptive Homeostasis is the mechanism by which organisms dynamically expand or contract the homeostatic range of stress defense and repair systems, employing a veritable armory of signal transduction pathways (such as the Keap1-Nrf2 system) to generate a complex profile of inducible and enzymatic protection that best fits the particular need. Viewed as a component of Adaptive Homeostasis, the Free Radical Theory of Aging appears both viable and robust.
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Affiliation(s)
- Laura C D Pomatto
- Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center, the University of Southern California, Los Angeles, CA 00089-0191, USA
| | - Kelvin J A Davies
- Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center, the University of Southern California, Los Angeles, CA 00089-0191, USA; Molecular and Computational Biology Program of the Department of Biological Sciences, Dornsife College of Letters, Arts, and sciences, the University of Southern California, Los Angeles, CA 90089-0191, USA; Department of Biochemistry & Molecular Medicine, Keck School of Medicine of USC, the University of Southern California, Los Angeles, CA, USA.
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Inhibition of Proteasome Activity Upregulates IL-6 Expression in RPE Cells through the Activation of P38 MAPKs. J Ophthalmol 2018; 2018:5392432. [PMID: 30116631 PMCID: PMC6079444 DOI: 10.1155/2018/5392432] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 06/19/2018] [Indexed: 12/22/2022] Open
Abstract
Purpose As far as we know, during the development of age-related macular degeneration (AMD), the activity of proteasome in retinal pigment epithelium cells (RPE) gradually decreases. And a lot of research has shown that age-related macular degeneration is closely related to inflammation and autoimmune. Moreover, there are many cytokines (CKs) involved in the course of inflammation. In this study, we are going to investigate how the decrease of proteasome activity affects the production of interleukin-6 (IL-6) in human retinal pigment epithelium cells (ARPE-19). Methods Cultured ARPE-19 was treated with or without MG132, a proteasome inhibitor, and the levels of IL-6 mRNA (messenger ribonucleic acid) in RPE at 1 h, 4 h, 8 h, and IL-6 protein in the culture medium at 2 h, 4 h, 6 h, 8 h, 10 h, and 12 h were measured by real-time polymerase chain reaction (real-time PCR) and enzyme-linked immunosorbent assay (ELISA). The protein levels of MCP-1 (monocyte chemoattractant protein-1) in the culture medium at 2 h, 4 h, 6 h, 8 h, 10 h, and 12 h were also measured by ELISA. Then we tested which of cell signal pathways regulating the production of IL-6 were activated when we added MG132 into the medium by Western blot and electrophoretic mobility shift assays (EMSA). After that, we put the inhibitors of these activated cell signal pathways into the medium individually to see which inhibitor can counteract the effect of upregulating the levels of IL-6 in the culture medium of RPE. Results MG132 decreased the secretion of MCP-1 in the culture medium of RPE, but it increased the expression of IL-6 mRNA in RPE and IL-6 protein level in the culture medium of RPE. MG132 treatment was also found to enhance the level of phosphorylated p38 mitogen-activated protein kinases (MAPKs) and c-Jun N-terminal Kinase (JNK) by Western blotting. More importantly, the effect of MG132 on upregulating the levels of IL-6 was inhibited by SB203580, an inhibitor of P38 MAP kinases. But the JNK inhibitor, SP600125, cannot prevent the effect of upregulating the levels of IL-6 by MG132 in the RPE culture medium. Conclusions We concluded that the proteasome inhibitor, MG132, upregulates IL-6 production in RPE cells through the activation of P38 MAPKs.
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Piippo N, Korhonen E, Hytti M, Skottman H, Kinnunen K, Josifovska N, Petrovski G, Kaarniranta K, Kauppinen A. Hsp90 inhibition as a means to inhibit activation of the NLRP3 inflammasome. Sci Rep 2018; 8:6720. [PMID: 29712950 PMCID: PMC5928092 DOI: 10.1038/s41598-018-25123-2] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 04/12/2018] [Indexed: 02/07/2023] Open
Abstract
Once activated, the intracellular receptor NLRP3 assembles an inflammasome protein complex that facilitates the caspase-1-mediated maturation of IL-1β and IL-18. Inactive NLRP3 is guarded by a protein complex containing Hsp90. In response to stress stimuli, Hsp90 is released, and NLRP3 can be activated to promote inflammation. In this study, we blocked Hsp90 with geldanamycin and studied the fate of NLRP3 in human retinal pigment epithelial (RPE) cells. RPE cells play a central role in the development of age-related macular degeneration (AMD), a progressive eye disease causing severe vision loss in the elderly. IL-1α-primed ARPE-19 cells, human embryonal stem cell (hESC)-derived RPE cells, and primary human RPE cells were exposed to MG-132 and bafilomycin A to activate NLRP3 via the inhibition of proteasomes and autophagy, respectively. Additionally, RPE cells were treated with geldanamycin at different time points and the levels of NLRP3 and IL-1β were determined. Caspase-1 activity was measured using a commercial assay. Geldanamycin prevented the activation of the inflammasome in human RPE cells. NLRP3 released from its protective complex became degraded by autophagy or secreted from the cells. Controlled destruction of NLRP3 is a potential way to regulate the inflammation associated with chronic diseases, such as AMD.
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Affiliation(s)
- Niina Piippo
- School of Pharmacy, University of Eastern Finland, Kuopio, 70211, Finland
| | - Eveliina Korhonen
- School of Pharmacy, University of Eastern Finland, Kuopio, 70211, Finland
| | - Maria Hytti
- School of Pharmacy, University of Eastern Finland, Kuopio, 70211, Finland
| | - Heli Skottman
- Faculty of Medicine and Life Sciences, BioMediTech, University of Tampere, Tampere, 33014, Finland
| | - Kati Kinnunen
- Department of Ophthalmology, Kuopio University Hospital, Kuopio, 70211, Finland
| | - Natasha Josifovska
- Stem Cells and Eye Research Laboratory, Department of Ophthalmology, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Szeged, Hungary
| | - Goran Petrovski
- Stem Cells and Eye Research Laboratory, Department of Ophthalmology, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Szeged, Hungary.,Center for Eye Research, Department of Ophthalmology, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Kai Kaarniranta
- Department of Ophthalmology, Kuopio University Hospital, Kuopio, 70211, Finland.,Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, 70211, Finland
| | - Anu Kauppinen
- School of Pharmacy, University of Eastern Finland, Kuopio, 70211, Finland.
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Kivinen N. The role of autophagy in age-related macular degeneration. Acta Ophthalmol 2018; 96 Suppl A110:1-50. [PMID: 29633521 DOI: 10.1111/aos.13753] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Niko Kivinen
- Department of Ophthalmology; University of Eastern Finland; Kuopio Finland
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Ramos de Carvalho JE, Verwoert MT, Vogels IM, Reits EA, Van Noorden CJ, Klaassen I, Schlingemann RO. Involvement of the ubiquitin-proteasome system in the expression of extracellular matrix genes in retinal pigment epithelial cells. Biochem Biophys Rep 2018; 13:83-92. [PMID: 29387813 PMCID: PMC5789218 DOI: 10.1016/j.bbrep.2018.01.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 01/08/2018] [Accepted: 01/09/2018] [Indexed: 01/06/2023] Open
Abstract
Emerging evidence suggests that dysfunction of the ubiquitin-proteasome system is involved in the pathogenesis of numerous senile degenerative diseases including retinal disorders. The aim of this study was to assess whether there is a link between proteasome regulation and retinal pigment epithelium (RPE)-mediated expression of extracellular matrix genes. For this purpose, human retinal pigment epithelial cells (ARPE-19) were treated with different concentrations of transforming growth factor-β (TGFβ), connective tissue growth factor (CTGF), interferon-γ (IFNγ) and the irreversible proteasome inhibitor epoxomicin. First, cytotoxicity and proliferation assays were carried out. The expression of proteasome-related genes and proteins was assessed and proteasome activity was determined. Then, expression of fibrosis-associated factors fibronectin (FN), fibronectin EDA domain (FN EDA), metalloproteinase-2 (MMP-2), tissue inhibitor of metalloproteinases-1 (TIMP-1) and peroxisome proliferator-associated receptor-γ (PPARγ) was assessed. The proteasome inhibitor epoxomicin strongly arrested cell cycle progression and down-regulated TGFβ gene expression, which in turn was shown to induce expression of pro-fibrogenic genes in ARPE-19 cells. Furthermore, epoxomicin induced a directional shift in the balance between MMP-2 and TIMP-1 and was associated with down-regulation of transcription of extracellular matrix genes FN and FN-EDA and up-regulation of the anti-fibrogenic factor PPARγ. In addition, both CTGF and TGFβ were shown to affect expression of proteasome-associated mRNA and protein levels. Our results suggest a link between proteasome activity and pro-fibrogenic mechanisms in the RPE, which could imply a role for proteasome-modulating agents in the treatment of retinal disorders characterized by RPE-mediated fibrogenic responses.
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Key Words
- AMD, age-related macular degeneration
- ARPE-19, human retinal pigment epithelial cells
- CNV, choroidal neovascularization
- CTGF
- CTGF, connective tissue growth factor
- ECM, extracellular matrix
- EMT, epithelial-mesenchymal transition
- Epoxomicin
- FN EDA, fibronectin EDA domain
- FN, fibronectin
- Fibrosis
- IFNγ, interferon-γ
- MMP-2, matrix metalloproteinase-2
- PPARγ
- PPARγ, peroxisome proliferator-associated receptor-γ
- Proteasome
- RPE
- RPE, retinal pigment epithelium
- Retina
- TGFβ
- TGFβ, transforming growth factor-β
- TIMP-1, tissue inhibitor of metalloproteinases-1
- UPS, ubiquitin-proteasome system
- nAMD, neovascular age-related macular degeneration
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Affiliation(s)
- J. Emanuel Ramos de Carvalho
- Ocular Angiogenesis Group, Departments of Ophthalmology and Medical Biology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Milan T. Verwoert
- Ocular Angiogenesis Group, Departments of Ophthalmology and Medical Biology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Ilse M.C. Vogels
- Ocular Angiogenesis Group, Departments of Ophthalmology and Medical Biology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Eric A. Reits
- Department of Medical Biology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Cornelis J.F. Van Noorden
- Ocular Angiogenesis Group, Departments of Ophthalmology and Medical Biology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Department of Medical Biology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Ingeborg Klaassen
- Ocular Angiogenesis Group, Departments of Ophthalmology and Medical Biology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Reinier O. Schlingemann
- Ocular Angiogenesis Group, Departments of Ophthalmology and Medical Biology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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Gao FJ, Wu JH, Li TT, Du SS, Wu Q. Identification of Mesencephalic Astrocyte-Derived Neurotrophic Factor as a Novel Neuroprotective Factor for Retinal Ganglion Cells. Front Mol Neurosci 2017; 10:76. [PMID: 28367115 PMCID: PMC5355452 DOI: 10.3389/fnmol.2017.00076] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 03/06/2017] [Indexed: 01/04/2023] Open
Abstract
Mesencephalic astrocyte-derived neurotrophic factor (MANF), a newly discovered secreted neurotrophic factor, has been proven to not only protect dopaminergic neurons and other cell types but also regulate neuroinflammation and the immune response to promote tissue repair and regeneration. However, to date, there is no information regarding the relationship between MANF and retinal ganglion cells (RGCs) in the eye. In the current study, we first determined the expression of MANF in the retina and vitreous. Then, we examined the effect of MANF on RGCs using both in vivo and in vitro models and simultaneously explored the underlying neuroprotective mechanisms of MANF. Finally, we measured the concentrations of MANF in the vitreous of patients with different retinopathies. We demonstrated that MANF was highly expressed in RGCs and that exogenous MANF could protect RGCs from hypoxia-induced cell injury and apoptosis both in vitro and in vivo by preventing endoplasmic reticulum stress-mediated apoptosis. Furthermore, MANF can be detected in the vitreous humor, and the concentration changed under pathological conditions. Our results provide important evidence that MANF may be a potential therapeutic protein for a range of retinal pathologies in either the preclinical stage or after diagnosis to promote the survival of RGCs. Vitreous MANF may be a promising protein biomarker for the indirect assessment of retinal disorders, which could provide indirect evidence of retinal pathology.
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Affiliation(s)
- Feng-Juan Gao
- Department of Ophthalmology, Shanghai Jiao Tong University Affiliated Sixth People's HospitalShanghai, China; Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai Medical College, Fudan UniversityShanghai, China
| | - Ji-Hong Wu
- Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai Medical College, Fudan UniversityShanghai, China; Shanghai Key Laboratory of Visual Impairment and RestorationShanghai, China; Key Laboratory of Myopia, Ministry of Health, Fudan UniversityShanghai, China
| | - Ting-Ting Li
- Department of Ophthalmology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital Shanghai, China
| | - Shan-Shan Du
- Department of Ophthalmology, The First Affiliated Hospital of Zhengzhou University Zhengzhou, China
| | - Qiang Wu
- Department of Ophthalmology, Shanghai Jiao Tong University Affiliated Sixth People's HospitalShanghai, China; Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Jiao Tong University Affiliated Sixth People's HospitalShanghai, China
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Song C, Mitter SK, Qi X, Beli E, Rao HV, Ding J, Ip CS, Gu H, Akin D, Dunn WA, Bowes Rickman C, Lewin AS, Grant MB, Boulton ME. Oxidative stress-mediated NFκB phosphorylation upregulates p62/SQSTM1 and promotes retinal pigmented epithelial cell survival through increased autophagy. PLoS One 2017; 12:e0171940. [PMID: 28222108 PMCID: PMC5319799 DOI: 10.1371/journal.pone.0171940] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 01/27/2017] [Indexed: 12/16/2022] Open
Abstract
p62 is a scaffolding adaptor implicated in the clearance of protein aggregates by autophagy. Reactive oxygen species (ROS) can either stimulate or inhibit NFκB-mediated gene expression influencing cellular fate. We studied the effect of hydrogen peroxide (H2O2)-mediated oxidative stress and NFκB signaling on p62 expression in the retinal pigment epithelium (RPE) and investigated its role in regulation of autophagy and RPE survival against oxidative damage. Cultured human RPE cell line ARPE-19 and primary human adult and fetal RPE cells were exposed to H2O2-induced oxidative stress. The human apolipoprotein E4 targeted-replacement (APOE4) mouse model of AMD was used to study expression of p62 and other autophagy proteins in the retina. p62, NFκB p65 (total, phosphorylated, nuclear and cytoplasmic) and ATG10 expression was assessed by mRNA and protein analyses. Cellular ROS and mitochondrial superoxide were measured by CM-H2DCFDA and MitoSOX staining respectively. Mitochondrial viability was determined using MTT activity. qPCR-array system was used to investigate autophagic genes affected by p62. Nuclear and cytoplasmic levels of NFκB p65 were evaluated after cellular fractionation by Western blotting. We report that p62 is up-regulated in RPE cells under H2O2-induced oxidative stress and promotes autophagic activity. Depletion of endogenous p62 reduces autophagy by downregulation of ATG10 rendering RPE more susceptible to oxidative damage. NFκB p65 phosphorylation at Ser-536 was found to be critical for p62 upregulation in response to oxidative stress. Proteasome inhibition by H2O2 causes p62-NFκB signaling as antioxidant pre-treatment reversed p62 expression and p65 phosphorylation when RPE was challenged by H2O2 but not when by Lactacystin. p62 protein but not RNA levels are elevated in APOE4-HFC AMD mouse model, suggesting reduction of autophagic flux in disease conditions. Our findings suggest that p62 is necessary for RPE cytoprotection under oxidative stress and functions, in part, by modulating ATG10 expression. NFκB p65 activity may be a critical upstream initiator of p62 expression in RPE cells under oxidative stress.
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Affiliation(s)
- Chunjuan Song
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, Florida, United States of America
| | - Sayak K Mitter
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Xiaoping Qi
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Eleni Beli
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Haripriya V Rao
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, Florida, United States of America
| | - Jindong Ding
- Departments of Ophthalmology and Cell Biology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Colin S Ip
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Hongmei Gu
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Debra Akin
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, Florida, United States of America
| | - William A Dunn
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, Florida, United States of America
| | - Catherine Bowes Rickman
- Departments of Ophthalmology and Cell Biology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Alfred S Lewin
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, United States of America
| | - Maria B Grant
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Michael E Boulton
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
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12
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Gao FJ, Zhang SH, Li TT, Wu JH, Wu Q. Expression and Distribution of Mesencephalic Astrocyte-Derived Neurotrophic Factor in the Retina and Optic Nerve. Front Hum Neurosci 2017; 10:686. [PMID: 28154531 PMCID: PMC5243802 DOI: 10.3389/fnhum.2016.00686] [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: 06/14/2016] [Accepted: 12/23/2016] [Indexed: 02/02/2023] Open
Abstract
Mesencephalic astrocyte-derived neurotrophic factor (MANF), otherwise named Arginine-Rich, Mutated in Early-stage Tumors (ARMET), is a secretory endoplasmic reticulum stress (ERS) protein that is widely expressed in mammalian tissues. To date, little is known about the distribution and expression of MANF in the retina and optic nerve (ON). Therefore, we studied the expression and distribution of MANF in the ON and retina by real-time PCR, immunofluorescence staining and western blotting. Results from rat and mouse were highly consistent in the retina. MANF was detected in both tissues in rat, wherein it was principally localized to the ganglion cell layer (GCL), followed by the inner nuclear layer (INL). The MANF protein levels in the rat retina were 3.33-fold higher than in the rat ON. Additionally, MANF was robustly expressed by retinal ganglion cells (RGCs) in the human retina. In human ON, MANF was partially co-localized with glial fibrillary acidic protein (GFAP), suggesting that it was not restricted to astrocytes. In vitro studies confirmed that MANF could be robustly expressed in RGCs and was found principally within the cytoplasm. Hypoxia can stimulate up-regulation by of MANF expression over time, suggesting that MANF may play a vital role in the functional regulation of RGCs both in health and disease. We believe that the present study improves our understanding of the distribution and expression of MANF in the retina and ON and could help in further analysis of its interact and correlate with the relevant ophthalmic diseases.
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Affiliation(s)
- Feng-Juan Gao
- Department of Ophthalmology, Shanghai Jiao Tong University Affiliated Sixth People's HospitalShanghai, China
| | - Sheng-Hai Zhang
- Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai Medical College, Fudan UniversityShanghai, China
- Shanghai Key Laboratory of Visual Impairment and RestorationShanghai, China
- Key Laboratory of Myopia, Ministry of Health, Fudan UniversityShanghai, China
| | - Ting-Ting Li
- Department of Ophthalmology, Shanghai Jiao Tong University Affiliated Sixth People's HospitalShanghai, China
| | - Ji-Hong Wu
- Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai Medical College, Fudan UniversityShanghai, China
- Shanghai Key Laboratory of Visual Impairment and RestorationShanghai, China
- Key Laboratory of Myopia, Ministry of Health, Fudan UniversityShanghai, China
| | - Qiang Wu
- Department of Ophthalmology, Shanghai Jiao Tong University Affiliated Sixth People's HospitalShanghai, China
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13
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Bemporad F, Ramazzotti M. From the Evolution of Protein Sequences Able to Resist Self-Assembly to the Prediction of Aggregation Propensity. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 329:1-47. [PMID: 28109326 DOI: 10.1016/bs.ircmb.2016.08.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Folding of polypeptide chains into biologically active entities is an astonishingly complex process, determined by the nature and the sequence of residues emerging from ribosomes. While it has been long believed that evolution has pressed genomes so that specific sequences could adopt unique, functional three-dimensional folds, it is now clear that complex protein machineries act as quality control system and supervise folding. Notwithstanding that, events such as erroneous folding, partial folding, or misfolding are frequent during the life of a cell or a whole organism, and they can escape controls. One of the possible outcomes of this misbehavior is cross-β aggregation, a super secondary structure which represents the hallmark of self-assembled, well organized, and extremely ordered structures termed amyloid fibrils. What if evolution would have not taken into account such possibilities? Twenty years of research point toward the idea that, in fact, evolution has constantly supervised the risk of errors and minimized their impact. In this review we tried to survey the major findings in the amyloid field, trying to describe what the real pitfalls of protein folding are-from an evolutionary perspective-and how sequence and structural features have evolved to balance the need for perfect, dynamic, functionally efficient structures, and the detrimental effects implicit in the dangerous process of folding. We will discuss how the knowledge obtained from these studies has been employed to produce computational methods able to assess, predict, and discriminate the aggregation properties of protein sequences.
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Affiliation(s)
- F Bemporad
- Università degli Studi di Firenze, Firenze, Italy.
| | - M Ramazzotti
- Università degli Studi di Firenze, Firenze, Italy.
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14
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Kivinen N, Felszeghy S, Kinnunen AI, Setälä N, Aikio M, Kinnunen K, Sironen R, Pihlajaniemi T, Kauppinen A, Kaarniranta K. Absence of collagen XVIII in mice causes age-related insufficiency in retinal pigment epithelium proteostasis. Biogerontology 2016; 17:749-61. [DOI: 10.1007/s10522-016-9647-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 04/21/2016] [Indexed: 01/26/2023]
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15
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Essential role of proteasomes in maintaining self-renewal in neural progenitor cells. Sci Rep 2016; 6:19752. [PMID: 26804982 PMCID: PMC4726439 DOI: 10.1038/srep19752] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 12/17/2015] [Indexed: 11/29/2022] Open
Abstract
Protein turnover and homeostasis are regulated by the proteasomal system, which is critical for cell function and viability. Pluripotency of stem cells also relies on normal proteasomal activity that mitigates senescent phenotypes induced by intensive cell replications, as previously demonstrated in human bone marrow stromal cells. In this study, we investigated the role of proteasomes in self-renewal of neural progenitor cells (NPCs). Through both in vivo and in vitro analyses, we found that the expression of proteasomes was progressively decreased during aging. Likewise, proliferation and self-renewal of NPCs were also impaired in aged mice, suggesting that the down-regulation of proteasomes might be responsible for this senescent phenotype. Lowering proteasomal activity by loss-of-function manipulations mimicked the senescence of NPCs both in vitro and in vivo; conversely, enhancing proteasomal activity restored and improved self-renewal in aged NPCs. These results collectively indicate that proteasomes work as a key regulator in promoting self-renewal of NPCs. This potentially provides a promising therapeutic target for age-dependent neurodegenerative diseases.
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16
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Ferrington DA, Sinha D, Kaarniranta K. Defects in retinal pigment epithelial cell proteolysis and the pathology associated with age-related macular degeneration. Prog Retin Eye Res 2015; 51:69-89. [PMID: 26344735 DOI: 10.1016/j.preteyeres.2015.09.002] [Citation(s) in RCA: 165] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 08/29/2015] [Accepted: 09/01/2015] [Indexed: 12/12/2022]
Abstract
Maintenance of protein homeostasis, also referred to as "Proteostasis", integrates multiple pathways that regulate protein synthesis, folding, translocation, and degradation. Failure in proteostasis may be one of the underlying mechanisms responsible for the cascade of events leading to age-related macular degeneration (AMD). This review covers the major degradative pathways (ubiquitin-proteasome and lysosomal involvement in phagocytosis and autophagy) in the retinal pigment epithelium (RPE) and summarizes evidence of their involvement in AMD. Degradation of damaged and misfolded proteins via the proteasome occurs in coordination with heat shock proteins. Evidence of increased content of proteasome and heat shock proteins in retinas from human donors with AMD is consistent with increased oxidative stress and extensive protein damage with AMD. Phagocytosis and autophagy share key molecules in phagosome maturation as well as degradation of their cargo following fusion with lysosomes. Phagocytosis and degradation of photoreceptor outer segments ensures functional integrity of the neural retina. Autophagy rids the cell of toxic protein aggregates and defective mitochondria. Evidence suggesting a decline in autophagic flux includes the accumulation of autophagic substrates and damaged mitochondria in RPE from AMD donors. An age-related decrease in lysosomal enzymatic activity inhibits autophagic clearance of outer segments, mitochondria, and protein aggregates, thereby accelerating the accumulation of lipofuscin. This cumulative damage over a person's lifetime tips the balance in RPE from a state of para-inflammation, which strives to restore cell homeostasis, to the chronic inflammation associated with AMD.
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Affiliation(s)
- Deborah A Ferrington
- Department of Ophthalmology and Visual Neurosciences, 2001 6th St SE, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Debasish Sinha
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Room M035 Robert and Clarice Smith Bldg, 400 N Broadway, Baltimore, MD, 21287, USA.
| | - Kai Kaarniranta
- Department of Ophthalmology, University of Eastern Finland and Kuopio University Hospital, P.O. Box 100, 70029 KYS, Finland.
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17
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Sinha D, Valapala M, Shang P, Hose S, Grebe R, Lutty GA, Zigler JS, Kaarniranta K, Handa JT. Lysosomes: Regulators of autophagy in the retinal pigmented epithelium. Exp Eye Res 2015; 144:46-53. [PMID: 26321509 DOI: 10.1016/j.exer.2015.08.018] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 07/09/2015] [Accepted: 08/18/2015] [Indexed: 12/19/2022]
Abstract
The retinal pigmented epithelium (RPE) is critically important to retinal homeostasis, in part due to its very active processes of phagocytosis and autophagy. Both of these processes depend upon the normal functioning of lysosomes, organelles which must fuse with (auto)phagosomes to deliver the hydrolases that effect degradation of cargo. It has become clear that signaling through mTOR complex 1 (mTORC1), is very important in the regulation of lysosomal function. This signaling pathway is becoming a target for therapeutic intervention in diseases, including age-related macular degeneration (AMD), where lysosomal function is defective. In addition, our laboratory has been studying animal models in which the gene (Cryba1) for βA3/A1-crystallin is deficient. These animals exhibit impaired lysosomal clearance in the RPE and pathological signs that are similar to some of those seen in AMD patients. The data demonstrate that βA3/A1-crystallin localizes to lysosomes in the RPE and that it is a binding partner of V-ATPase, the proton pump that acidifies the lysosomal lumen. This suggests that βA3/A1-crystallin may also be a potential target for therapeutic intervention in AMD. In this review, we focus on effector molecules that impact the lysosomal-autophagic pathway in RPE cells.
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Affiliation(s)
- Debasish Sinha
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Mallika Valapala
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Peng Shang
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Ophthalmology of Shanghai Tenth Hospital and Tongji Eye Institute, Tongji University School of Medicine, Shanghai, China
| | - Stacey Hose
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Rhonda Grebe
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Gerard A Lutty
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - J Samuel Zigler
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine and Kuopio University Hospital, University of Eastern Finland, Kuopio, Finland
| | - James T Handa
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
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18
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Singh R, Kuai D, Guziewicz KE, Meyer J, Wilson M, Lu J, Smith M, Clark E, Verhoeven A, Aguirre GD, Gamm DM. Pharmacological Modulation of Photoreceptor Outer Segment Degradation in a Human iPS Cell Model of Inherited Macular Degeneration. Mol Ther 2015; 23:1700-1711. [PMID: 26300224 DOI: 10.1038/mt.2015.141] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 07/23/2015] [Indexed: 12/16/2022] Open
Abstract
Degradation of photoreceptor outer segments (POS) by retinal pigment epithelium (RPE) is essential for vision, and studies have implicated altered POS processing in the pathogenesis of some retinal degenerative diseases. Consistent with this concept, a recently established hiPSC-RPE model of inherited macular degeneration, Best disease (BD), displayed reduced rates of POS breakdown. Herein we utilized this model to determine (i) if disturbances in protein degradation pathways are associated with delayed POS digestion and (ii) whether such defect(s) can be pharmacologically targeted. We found that BD hiPSC-RPE cultures possessed increased protein oxidation, decreased free-ubiquitin levels, and altered rates of exosome secretion, consistent with altered POS processing. Application of valproic acid (VPA) with or without rapamycin increased rates of POS degradation in our model, whereas application of bafilomycin-A1 decreased such rates. Importantly, the negative effect of bafilomycin-A1 could be fully reversed by VPA. The utility of hiPSC-RPE for VPA testing was further evident following examination of its efficacy and metabolism in a complementary canine disease model. Our findings suggest that disturbances in protein degradation pathways contribute to the POS processing defect observed in BD hiPSC-RPE, which can be manipulated pharmacologically. These results have therapeutic implications for BD and perhaps other maculopathies.
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Affiliation(s)
- Ruchira Singh
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA; McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin, USA
| | - David Kuai
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Karina E Guziewicz
- Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jackelyn Meyer
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Molly Wilson
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jianfeng Lu
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Molly Smith
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Eric Clark
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Amelia Verhoeven
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Gustavo D Aguirre
- Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - David M Gamm
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA; McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin, USA; Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin, USA.
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19
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Piippo N, Korkmaz A, Hytti M, Kinnunen K, Salminen A, Atalay M, Kaarniranta K, Kauppinen A. Decline in cellular clearance systems induces inflammasome signaling in human ARPE-19 cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:3038-46. [PMID: 25268952 DOI: 10.1016/j.bbamcr.2014.09.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 09/15/2014] [Accepted: 09/16/2014] [Indexed: 11/25/2022]
Abstract
Retinal pigment epithelium (RPE) plays a major role in the maintenance of photoreceptors, and degeneration of RPE results in the development of age-related macular degeneration (AMD). Accumulation of intracellular protein aggregates, increased oxidative stress, and chronic inflammation are all factors damaging the functionality of aged RPE cells. Here, we report that inhibition of proteasomal degradation with MG-132 and autophagy with bafilomycin A1 resulted in the release of IL-1β but not that of IL-18 in human ARPE-19 cells. NLRP3 receptor became upregulated, and caspase-1, the functional component of an inflammasome complex, was activated. In addition to accumulating intracellular protein aggregates, inhibition of degradation systems induced oxidative stress which was demonstrated by elevated amounts of intracellular 4-hydroxynonenal (HNE)-protein adducts. Along with IL-1β, exposure to MG-132 and bafilomycin A1 resulted in the secretion of IL-8. A low concentration (1pg/ml) of IL-1β was capable of triggering significant IL-8 production which also became attenuated by treatment with a specific caspase-1 inhibitor. These results suggest that decline in intracellular degradation systems results not only in increased amounts of intracellular protein aggregates and oxidative stress but also in the activation of NLRP3 inflammasomes, arisen as a result of elevated production of biologically active IL-1β.
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Affiliation(s)
- Niina Piippo
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Ayhan Korkmaz
- Institute of Biomedicine, Physiology, University of Eastern Finland, Kuopio, Finland
| | - Maria Hytti
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Kati Kinnunen
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, Kuopio, Finland
| | - Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland; Department of Neurology, Kuopio University Hospital, Kuopio, Finland
| | - Mustafa Atalay
- Institute of Biomedicine, Physiology, University of Eastern Finland, Kuopio, Finland
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, Kuopio, Finland
| | - Anu Kauppinen
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, Kuopio, Finland.
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20
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Kaarniranta K, Machalińska A, Veréb Z, Salminen A, Petrovski G, Kauppinen A. Estrogen signalling in the pathogenesis of age-related macular degeneration. Curr Eye Res 2014; 40:226-33. [PMID: 24911983 DOI: 10.3109/02713683.2014.925933] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Age-related macular degeneration (AMD) is a multifactorial eye disease that is associated with aging, family history, smoking, obesity, cataract surgery, arteriosclerosis, hypertension, hypercholesterolemia and unhealthy diet. Gender has commonly been classified as a weak or inconsistent risk factor for AMD. This disease is characterized by degeneration of retinal pigment epithelial (RPE) cells, Bruch's membrane, and choriocapillaris, which secondarily lead to damage and death of photoreceptor cells and central visual loss. Pathogenesis of AMD involves constant oxidative stress, chronic inflammation, and increased accumulation of lipofuscin and drusen. Estrogen has both anti-oxidative and anti-inflammatory capacity and it regulates signaling pathways that are involved in the pathogenesis of AMD. In this review, we discuss potential cellular signaling targets of estrogen in retinal cells and AMD pathology.
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Affiliation(s)
- Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland , Kuopio , Finland
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21
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Viiri J, Amadio M, Marchesi N, Hyttinen JMT, Kivinen N, Sironen R, Rilla K, Akhtar S, Provenzani A, D'Agostino VG, Govoni S, Pascale A, Agostini H, Petrovski G, Salminen A, Kaarniranta K. Autophagy activation clears ELAVL1/HuR-mediated accumulation of SQSTM1/p62 during proteasomal inhibition in human retinal pigment epithelial cells. PLoS One 2013; 8:e69563. [PMID: 23922739 PMCID: PMC3726683 DOI: 10.1371/journal.pone.0069563] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 06/10/2013] [Indexed: 12/21/2022] Open
Abstract
Age-related macular degeneration (AMD) is the most common reason of visual impairment in the elderly in the Western countries. The degeneration of retinal pigment epithelial cells (RPE) causes secondarily adverse effects on neural retina leading to visual loss. The aging characteristics of the RPE involve lysosomal accumulation of lipofuscin and extracellular protein aggregates called “drusen”. Molecular mechanisms behind protein aggregations are weakly understood. There is intriguing evidence suggesting that protein SQSTM1/p62, together with autophagy, has a role in the pathology of different degenerative diseases. It appears that SQSTM1/p62 is a connecting link between autophagy and proteasome mediated proteolysis, and expressed strongly under the exposure to various oxidative stimuli and proteasomal inhibition. ELAVL1/HuR protein is a post-transcriptional factor, which acts mainly as a positive regulator of gene expression by binding to specific mRNAs whose corresponding proteins are fundamental for key cellular functions. We here show that, under proteasomal inhibitor MG-132, ELAVL1/HuR is up-regulated at both mRNA and protein levels, and that this protein binds and post-transcriptionally regulates SQSTM1/p62 mRNA in ARPE-19 cell line. Furthermore, we observed that proteasomal inhibition caused accumulation of SQSTM1/p62 bound irreversibly to perinuclear protein aggregates. The addition of the AMPK activator AICAR was pro-survival and promoted cleansing by autophagy of the former complex, but not of the ELAVL1/HuR accumulation, indeed suggesting that SQSTM1/p62 is decreased through autophagy-mediated degradation, while ELAVL1/HuR through the proteasomal pathway. Interestingly, when compared to human controls, AMD donor samples show strong SQSTM1/p62 rather than ELAVL1/HuR accumulation in the drusen rich macular area suggesting impaired autophagy in the pathology of AMD.
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Affiliation(s)
- Johanna Viiri
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Marialaura Amadio
- Department of Drug Sciences, Pharmacology Section, University of Pavia, Pavia, Italy
| | - Nicoletta Marchesi
- Department of Drug Sciences, Pharmacology Section, University of Pavia, Pavia, Italy
| | - Juha M. T. Hyttinen
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Niko Kivinen
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Reijo Sironen
- Institute of Clinical Medicine, Pathology and Forensic Medicine, University of Eastern Finland, Kuopio, Finland
- Department of Clinical Pathology, Kuopio University Hospital, Kuopio, Finland
- Biocenter Kuopio and Cancer Center of Eastern Finland, University of Eastern Finland, Kuopio, Finland
| | - Kirsi Rilla
- Department of Anatomy, School of Medicine, Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Saeed Akhtar
- Department of Optometry and Vision Sciences College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Alessandro Provenzani
- Laboratory of Genomic Screening, Centre for Integrative Biology, University of Trento, Trento, Italy
| | - Vito Giuseppe D'Agostino
- Laboratory of Genomic Screening, Centre for Integrative Biology, University of Trento, Trento, Italy
| | - Stefano Govoni
- Department of Drug Sciences, Pharmacology Section, University of Pavia, Pavia, Italy
| | - Alessia Pascale
- Department of Drug Sciences, Pharmacology Section, University of Pavia, Pavia, Italy
| | - Hansjurgen Agostini
- Department of Ophthalmology, University Eye Hospital, Albert-Ludwigs University of Freiburg, Freiburg im Breisgau, Germany
| | - Goran Petrovski
- Department of Ophthalmology, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary
- Stem Cells and Eye Research Laboratory, Department of Biochemistry and Molecular Biology, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary
| | - Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
- Department of Neurology, Kuopio University Hospital, Kuopio, Finland
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
- Department of Ophthalmology, Kuopio University Hospital, Kuopio, Finland
- * E-mail:
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22
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Kaarniranta K, Sinha D, Blasiak J, Kauppinen A, Veréb Z, Salminen A, Boulton ME, Petrovski G. Autophagy and heterophagy dysregulation leads to retinal pigment epithelium dysfunction and development of age-related macular degeneration. Autophagy 2013; 9:973-84. [PMID: 23590900 PMCID: PMC3722332 DOI: 10.4161/auto.24546] [Citation(s) in RCA: 239] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Age-related macular degeneration (AMD) is a complex, degenerative and progressive eye disease that usually does not lead to complete blindness, but can result in severe loss of central vision. Risk factors for AMD include age, genetics, diet, smoking, oxidative stress and many cardiovascular-associated risk factors. Autophagy is a cellular housekeeping process that removes damaged organelles and protein aggregates, whereas heterophagy, in the case of the retinal pigment epithelium (RPE), is the phagocytosis of exogenous photoreceptor outer segments. Numerous studies have demonstrated that both autophagy and heterophagy are highly active in the RPE. To date, there is increasing evidence that constant oxidative stress impairs autophagy and heterophagy, as well as increases protein aggregation and causes inflammasome activation leading to the pathological phenotype of AMD. This review ties together these crucial pathological topics and reflects upon autophagy as a potential therapeutic target in AMD.
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Affiliation(s)
- Kai Kaarniranta
- Department of Ophthalmology; Institute of Clinical Medicine; University of Eastern Finland; Kuopio, Finland; Department of Ophthalmology; Kuopio University Hospital; Kuopio, Finland
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23
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Chondrogianni N, Petropoulos I, Grimm S, Georgila K, Catalgol B, Friguet B, Grune T, Gonos ES. Protein damage, repair and proteolysis. Mol Aspects Med 2012; 35:1-71. [PMID: 23107776 DOI: 10.1016/j.mam.2012.09.001] [Citation(s) in RCA: 160] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 09/26/2012] [Indexed: 01/10/2023]
Abstract
Proteins are continuously affected by various intrinsic and extrinsic factors. Damaged proteins influence several intracellular pathways and result in different disorders and diseases. Aggregation of damaged proteins depends on the balance between their generation and their reversal or elimination by protein repair systems and degradation, respectively. With regard to protein repair, only few repair mechanisms have been evidenced including the reduction of methionine sulfoxide residues by the methionine sulfoxide reductases, the conversion of isoaspartyl residues to L-aspartate by L-isoaspartate methyl transferase and deglycation by phosphorylation of protein-bound fructosamine by fructosamine-3-kinase. Protein degradation is orchestrated by two major proteolytic systems, namely the lysosome and the proteasome. Alteration of the function for both systems has been involved in all aspects of cellular metabolic networks linked to either normal or pathological processes. Given the importance of protein repair and degradation, great effort has recently been made regarding the modulation of these systems in various physiological conditions such as aging, as well as in diseases. Genetic modulation has produced promising results in the area of protein repair enzymes but there are not yet any identified potent inhibitors, and, to our knowledge, only one activating compound has been reported so far. In contrast, different drugs as well as natural compounds that interfere with proteolysis have been identified and/or developed resulting in homeostatic maintenance and/or the delay of disease progression.
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Affiliation(s)
- Niki Chondrogianni
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Helenic Research Foundation, 48 Vas. Constantinou Ave., 116 35 Athens, Greece.
| | - Isabelle Petropoulos
- Laboratoire de Biologie Cellulaire du Vieillissement, UR4-UPMC, IFR 83, Université Pierre et Marie Curie-Paris 6, 4 Place Jussieu, 75005 Paris, France
| | - Stefanie Grimm
- Department of Nutritional Toxicology, Institute of Nutrition, Friedrich-Schiller University, Dornburger Straße 24, 07743 Jena, Germany
| | - Konstantina Georgila
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Helenic Research Foundation, 48 Vas. Constantinou Ave., 116 35 Athens, Greece
| | - Betul Catalgol
- Department of Biochemistry, Faculty of Medicine, Genetic and Metabolic Diseases Research Center (GEMHAM), Marmara University, Haydarpasa, Istanbul, Turkey
| | - Bertrand Friguet
- Laboratoire de Biologie Cellulaire du Vieillissement, UR4-UPMC, IFR 83, Université Pierre et Marie Curie-Paris 6, 4 Place Jussieu, 75005 Paris, France
| | - Tilman Grune
- Department of Nutritional Toxicology, Institute of Nutrition, Friedrich-Schiller University, Dornburger Straße 24, 07743 Jena, Germany
| | - Efstathios S Gonos
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Helenic Research Foundation, 48 Vas. Constantinou Ave., 116 35 Athens, Greece.
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Blueberry anthocyanins: protection against ageing and light-induced damage in retinal pigment epithelial cells. Br J Nutr 2011; 108:16-27. [PMID: 22018225 DOI: 10.1017/s000711451100523x] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Retinal pigment epithelium (RPE) cells are vital for retinal health. However, they are susceptible to injury with ageing and exposure to excessive light, including UV (100-380 nm) and visible (380-760 nm) radiation. To evaluate the protective effect of blueberry anthocyanins on RPE cells, in vitro cell models of replicative senescent and light-induced damage were established in the present study. After purification and fractionation, blueberry anthocyanin extracts (BAE) were yielded with total anthocyanin contents of 31·0 (SD 0·5) % and were used in this study. Replicative senescence of RPE cells was induced by repeatedly passaging cells from the fourth passage to the tenth. From the fifth passage, cultured RPE cells began to enter a replicative senescence, exhibiting reduced cell proliferation along with an increase in the number of β-galactosidase-positive cells. RPE cells maintained high cell viability (P < 0·01) and a low (P < 0·01) percentage of β-galactosidase-positive cells when treated with 0·1 μg/ml BAE. In contrast, after exposure to 2500 (SD 500) lx light (420-800 nm) for 12 h, RPE cells in the positive control (light exposure, no BAE treatment) exhibited premature senescence, low (P < 0·01) cell viability and increased (P < 0·01) vascular endothelial growth factor (VEGF) release compared with negative control cells, which were not subjected to light irradiation and BAE exposure. Correspondingly, BAE is beneficial to RPE cells by protecting these cells against light-induced damage through the suppression of ageing and apoptosis as well as the down-regulation of the over-expressed VEGF to normal level. These results demonstrate that BAE is efficacious against senescence and light-induced damage of RPE cells.
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De Baets G, Reumers J, Delgado Blanco J, Dopazo J, Schymkowitz J, Rousseau F. An evolutionary trade-off between protein turnover rate and protein aggregation favors a higher aggregation propensity in fast degrading proteins. PLoS Comput Biol 2011; 7:e1002090. [PMID: 21731483 PMCID: PMC3121684 DOI: 10.1371/journal.pcbi.1002090] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Accepted: 04/28/2011] [Indexed: 12/29/2022] Open
Abstract
We previously showed the existence of selective pressure against protein aggregation by the enrichment of aggregation-opposing ‘gatekeeper’ residues at strategic places along the sequence of proteins. Here we analyzed the relationship between protein lifetime and protein aggregation by combining experimentally determined turnover rates, expression data, structural data and chaperone interaction data on a set of more than 500 proteins. We find that selective pressure on protein sequences against aggregation is not homogeneous but that short-living proteins on average have a higher aggregation propensity and fewer chaperone interactions than long-living proteins. We also find that short-living proteins are more often associated to deposition diseases. These findings suggest that the efficient degradation of high-turnover proteins is sufficient to preclude aggregation, but also that factors that inhibit proteasomal activity, such as physiological ageing, will primarily affect the aggregation of short-living proteins. In order to carry out their biological function, proteins need to fold into well-defined three-dimensional structures. Protein aggregation is a process whereby proteins misfold into inactive and often toxic higher order structures, which is implied in about 30 human diseases such as Alzheimer's disease, Parkinson's disease and systemic amyloidosis. In earlier work it has been shown that although protein aggregation is an intrinsic property of polypeptide chains that cannot be entirely avoided, evolution has optimized protein sequences to minimize the risk of aggregation in a proteome. Here we show that this pressure is not uniform, but that proteins with a short lifetime have on average a higher aggregation propensity than long-living proteins. In addition, we show that high turnover proteins also make fewer interactions with chaperones. Taken together, these observations suggest that under normal physiological conditions the aggregation propensity of short-lived proteins does not represent a significant treat for the biochemistry of the cell. Presumably the strong dependence of these proteins on proteasomal degradation is sufficient to preclude the accumulation of aggregates. As proteasomal activity declines with age this would also explain why we observe a higher association of high turnover proteins with age-dependent aggregation-related diseases.
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Influence of Hsp90 and HDAC inhibition and tubulin acetylation on perinuclear protein aggregation in human retinal pigment epithelial cells. J Biomed Biotechnol 2010; 2011:798052. [PMID: 20981255 PMCID: PMC2963810 DOI: 10.1155/2011/798052] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Accepted: 09/23/2010] [Indexed: 01/03/2023] Open
Abstract
Retinal pigment epithelial (RPE) cells are continually exposed to oxidative stress that contributes to protein misfolding, aggregation and functional abnormalities during aging. The protein aggregates formed at the cell periphery are delivered along the microtubulus network by dynein-dependent retrograde trafficking to a juxtanuclear location. We demonstrate that Hsp90 inhibition by geldanamycin can effectively suppress proteasome inhibitor, MG-132-induced protein aggregation in a way that is independent of HDAC inhibition or the tubulin acetylation levels in ARPE-19 cells. However, the tubulin acetylation and polymerization state affects the localization of the proteasome-inhibitor-induced aggregation. These findings open new perspectives for understanding the pathogenesis of protein aggregation in retinal cells and can be useful for the development of therapeutic treatments to prevent retinal cell deterioration.
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Salminen A, Kauppinen A, Hyttinen JM, Toropainen E, Kaarniranta K. Endoplasmic reticulum stress in age-related macular degeneration: trigger for neovascularization. Mol Med 2010; 16:535-42. [PMID: 20683548 DOI: 10.2119/molmed.2010.00070] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Accepted: 07/26/2010] [Indexed: 12/18/2022] Open
Abstract
Age-related macular degeneration (AMD) can be classified into two main categories: the atrophic, dry form and the exudative, wet form. The crucial difference between dry and wet AMD is the development of choroidal neovascularization in wet AMD. One fundamental cause of the neovascularization is the increased expression of VEGF (vascular endothelial growth factor) in retinal pigment epithelial cells. Progression of AMD is linked to augmentation of cellular stress, for example, oxidative stress, proteotoxic stress, inflammation and hypoxia. All these conditions can trigger stress in endoplasmic reticulum (ER), which maintains protein quality control in cells. ER stress induces the unfolded protein response (UPR) via IRE1 (inositol-requiring protein-1), PERK (protein kinase RNA-like ER kinase) and ATF6 (activating transcription factor-6) transducers. UPR signaling is a double-edged sword, that is, it can restore cellular homeostasis as far as possible, but ultimately may lead to chronic, overwhelming stress that can cause apoptotic cell death. Interestingly, ER stress is a well-known inducer of angiogenesis in cancer. Moreover, stress conditions associated with the progress of AMD can induce the expression of VEGF. We discuss the role of ER stress in the regulation of neovascularization and the conversion of dry AMD to its wet, detrimental counterpart.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, University of Eastern Finland, Kuopio, Finland.
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