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Martin MS, Jacob-Dolan JW, Pham VTT, Sjoblom NM, Scheck RA. The chemical language of protein glycation. Nat Chem Biol 2024:10.1038/s41589-024-01644-y. [PMID: 38942948 DOI: 10.1038/s41589-024-01644-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 05/10/2024] [Indexed: 06/30/2024]
Abstract
Glycation is a non-enzymatic post-translational modification (PTM) that is correlated with many diseases, including diabetes, cancer and age-related disorders. Although recent work points to the importance of glycation as a functional PTM, it remains an open question whether glycation has a causal role in cellular signaling and/or disease development. In this Review, we contextualize glycation as a specific mechanism of carbon stress and consolidate what is known about advanced glycation end-product (AGE) structures and mechanisms. We highlight the current understanding of glycation as a PTM, focusing on mechanisms for installing, removing or recognizing AGEs. Finally, we discuss challenges that have hampered a more complete understanding of the biological consequences of glycation. The development of tools for predicting, modulating, mimicking or capturing glycation will be essential for interpreting a post-translational glycation network. Therefore, continued insights into the chemistry of glycation will be necessary to advance understanding of glycation biology.
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2
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Dontsov A, Ostrovsky M. Retinal Pigment Epithelium Pigment Granules: Norms, Age Relations and Pathology. Int J Mol Sci 2024; 25:3609. [PMID: 38612421 PMCID: PMC11011557 DOI: 10.3390/ijms25073609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 03/20/2024] [Accepted: 03/21/2024] [Indexed: 04/14/2024] Open
Abstract
The retinal pigment epithelium (RPE), which ensures the normal functioning of the neural retina, is a pigmented single-cell layer that separates the retina from the Bruch's membrane and the choroid. There are three main types of pigment granules in the RPE cells of the human eye: lipofuscin granules (LG) containing the fluorescent "age pigment" lipofuscin, melanoprotein granules (melanosomes, melanolysosomes) containing the screening pigment melanin and complex melanolipofuscin granules (MLG) containing both types of pigments simultaneously-melanin and lipofuscin. This review examines the functional role of pigment granules in the aging process and in the development of oxidative stress and associated pathologies in RPE cells. The focus is on the process of light-induced oxidative degradation of pigment granules caused by reactive oxygen species. The reasons leading to increased oxidative stress in RPE cells as a result of the oxidative degradation of pigment granules are considered. A mechanism is proposed to explain the phenomenon of age-related decline in melanin content in RPE cells. The essence of the mechanism is that when the lipofuscin part of the melanolipofuscin granule is exposed to light, reactive oxygen species are formed, which destroy the melanin part. As more melanolipofuscin granules are formed with age and the development of degenerative diseases, the melanin in pigmented epithelial cells ultimately disappears.
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Affiliation(s)
| | - Mikhail Ostrovsky
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow 119334, Russia;
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3
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Zegeye Y, Aredo B, Yuksel S, Kirman DC, Kumar A, Chen B, Turpin E, Shresta S, He YG, Gautron L, Tang M, Li X, DiCesare SM, Hulleman JD, Xing C, Ludwig S, Moresco EMY, Beutler BA, Ufret-Vincenty RL. E3 ubiquitin ligase Herc3 deficiency leads to accumulation of subretinal microglia and retinal neurodegeneration. Sci Rep 2024; 14:3010. [PMID: 38321224 PMCID: PMC10847449 DOI: 10.1038/s41598-024-53731-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 02/04/2024] [Indexed: 02/08/2024] Open
Abstract
Activated microglia have been implicated in the pathogenesis of age-related macular degeneration (AMD), diabetic retinopathy, and other neurodegenerative and neuroinflammatory disorders, but our understanding of the mechanisms behind their activation is in infant stages. With the goal of identifying novel genes associated with microglial activation in the retina, we applied a semiquantitative fundus spot scoring scale to an unbiased, state-of-the-science mouse forward genetics pipeline. A mutation in the gene encoding the E3 ubiquitin ligase Herc3 led to prominent accumulation of fundus spots. CRISPR mutagenesis was used to generate Herc3-/- mice, which developed prominent accumulation of fundus spots and corresponding activated Iba1 + /CD16 + subretinal microglia, retinal thinning on OCT and histology, and functional deficits by Optomotory and electrophysiology. Bulk RNA sequencing identified activation of inflammatory pathways and differentially expressed genes involved in the modulation of microglial activation. Thus, despite the known expression of multiple E3 ubiquitin ligases in the retina, we identified a non-redundant role for Herc3 in retinal homeostasis. Our findings are significant given that a dysregulated ubiquitin-proteasome system (UPS) is important in prevalent retinal diseases, in which activated microglia appear to play a role. This association between Herc3 deficiency, retinal microglial activation and retinal degeneration merits further study.
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Affiliation(s)
- Yeshumenesh Zegeye
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Bogale Aredo
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Seher Yuksel
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Dogan Can Kirman
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Ashwani Kumar
- McDermott Center for Human Growth and Development, UT Southwestern Medical Center, Dallas, TX, USA
| | - Bo Chen
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Emily Turpin
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Sangita Shresta
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Yu-Guang He
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Laurent Gautron
- Center for Hypothalamic Research and Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Miao Tang
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xiaohong Li
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Sophia M DiCesare
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - John D Hulleman
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Chao Xing
- McDermott Center for Human Growth and Development, UT Southwestern Medical Center, Dallas, TX, USA
- Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX, USA
| | - Sara Ludwig
- Center for Hypothalamic Research and Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Eva Marie Y Moresco
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Bruce A Beutler
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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4
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Tao T, Xu N, Li J, Zhao M, Li X, Huang L. Conditional loss of Ube3d in the retinal pigment epithelium accelerates age-associated alterations in the retina of mice. J Pathol 2023; 261:442-454. [PMID: 37772657 DOI: 10.1002/path.6201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 07/07/2023] [Accepted: 08/11/2023] [Indexed: 09/30/2023]
Abstract
Several studies have suggested a correlation between the ubiquitin-proteasome system (UPS) and age-related macular degeneration (AMD), with its phenotypic severity ranging from mild visual impairment to blindness, but the mechanism for UPS dysfunction contributing to disease progression is unclear. In this study, we investigated the role of ubiquitin protein ligase E3D (UBE3D) in aging and degeneration in mouse retina. Conditional knockout of Ube3d in the retinal pigment epithelium (RPE) of mice led to progressive and irregular fundus lesions, attenuation of the retinal vascular system, and age-associated deterioration of rod and cone responses. Simultaneously, RPE-specific Ube3d knockout mice also presented morphological changes similar to the histopathological characteristics of human AMD, in which a defective UPS led to RPE abnormalities such as phagocytosis or degradation of metabolites, the interaction with photoreceptor outer segment, and the transport of nutrients or waste products with choroidal capillaries via Bruch's membrane. Moreover, conditional loss of Ube3d resulted in aberrant molecular characterizations associated with the autophagy-lysosomal pathway, oxidative stress damage, and cell-cycle regulation, which are implicated in AMD pathology. Thus, our findings strengthen and expand the impact of UPS dysfunction on retinal pathophysiology during aging, indicating that genetic Ube3d deficiency in the RPE could lead to the abnormal formation of pigment deposits and secondary fundus alterations. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Tianchang Tao
- Department of Ophthalmology, Peking University People's Hospital, Eye Diseases and Optometry Institute, Beijing, PR China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, PR China
- College of Optometry, Peking University Health Science Center, Beijing, PR China
- Department of Ophthalmology, The First Affiliated Hospital of Anhui Medical University, Hefei, PR China
| | - Ningda Xu
- Department of Ophthalmology, Peking University People's Hospital, Eye Diseases and Optometry Institute, Beijing, PR China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, PR China
- College of Optometry, Peking University Health Science Center, Beijing, PR China
| | - Jiarui Li
- Department of Ophthalmology, Peking University People's Hospital, Eye Diseases and Optometry Institute, Beijing, PR China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, PR China
- College of Optometry, Peking University Health Science Center, Beijing, PR China
| | - Mingwei Zhao
- Department of Ophthalmology, Peking University People's Hospital, Eye Diseases and Optometry Institute, Beijing, PR China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, PR China
- College of Optometry, Peking University Health Science Center, Beijing, PR China
| | - Xiaoxin Li
- Department of Ophthalmology, Peking University People's Hospital, Eye Diseases and Optometry Institute, Beijing, PR China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, PR China
- College of Optometry, Peking University Health Science Center, Beijing, PR China
- Department of Ophthalmology, Xiamen Eye Center of Xiamen University, Xiamen, PR China
| | - Lvzhen Huang
- Department of Ophthalmology, Peking University People's Hospital, Eye Diseases and Optometry Institute, Beijing, PR China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, PR China
- College of Optometry, Peking University Health Science Center, Beijing, PR China
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5
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Mohanty SK, Suchiang K. Baicalein mitigates oxidative stress and enhances lifespan through modulation of Wnt ligands and GATA factor: ELT-3 in Caenorhabditis elegans. Life Sci 2023; 329:121946. [PMID: 37463652 DOI: 10.1016/j.lfs.2023.121946] [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: 06/05/2023] [Revised: 07/07/2023] [Accepted: 07/14/2023] [Indexed: 07/20/2023]
Abstract
AIMS Age predispose individual to major diseases, and the biological processes contributing to aging are currently under intense investigation. Hence, plant-based natural compounds could be a potential target to counteract aging and age-associated diseases. So, the present study aims to investigate the antiaging properties of a natural compound Baicalein (BAI) on C. elegans and to elucidate the pathways or signaling molecules involved. METHODS Herein, we investigated the inhibitory effects of BAI on different Wnt ligands of C. elegans and its underlying mechanisms. Moreover, we monitored BAI's antiaging effect on the worms' lifespan and its different aging parameters. We employed different mutant and transgenic C. elegans strains to identify the pathways and transcription factors involved. KEY FINDINGS We first showed that BAI could downregulate different Wnt ligands mRNA expressions in C. elegans, resulting in enhanced expression of GATA transcription factor ELT-3 and antiaging gene Klotho. On further evaluation, it was observed that BAI could enhance the worm's lifespan via ELT-3 and SKN-1 transcription factors, whereas, for the protection of worms against external oxidative stress, both ELT-3 and DAF-16 transcription factors were involved. Moreover, sensitive aging parameters of worms, including lipofuscin and ROS accumulation, and the declined physiological and mechanical functions observed in aged worms were ameliorated by BAI. SIGNIFICANCE This study highlighted BAI as a promising antiaging compound. This study also revealed the Wnt inhibitory potential of BAI with future implications for pharmacological target of age-associated diseases with aberrant activation of the Wnt pathway.
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Affiliation(s)
- Saswat Kumar Mohanty
- Department of Biochemistry and Molecular Biology, Pondicherry University, Pondicherry 605 014, India
| | - Kitlangki Suchiang
- Department of Biochemistry and Molecular Biology, Pondicherry University, Pondicherry 605 014, India.
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6
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Weinberg J, Gaur M, Swaroop A, Taylor A. Proteostasis in aging-associated ocular disease. Mol Aspects Med 2022; 88:101157. [PMID: 36459837 PMCID: PMC9742340 DOI: 10.1016/j.mam.2022.101157] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 11/15/2022] [Indexed: 11/30/2022]
Abstract
Vision impairment has devastating consequences for the quality of human life. The cells and tissues associated with the visual process must function throughout one's life span and maintain homeostasis despite exposure to a variety of insults. Maintenance of the proteome is termed proteostasis, and is vital for normal cellular functions, especially at an advanced age. Here we describe basic aspects of proteostasis, from protein synthesis and folding to degradation, and discuss the current status of the field with a particular focus on major age-related eye diseases: age-related macular degeneration, cataract, and glaucoma. Our intent is to allow vision scientists to determine where and how to harness the proteostatic machinery for extending functional homeostasis in the aging retina, lens, and trabecular meshwork. Several common themes have emerged despite these tissues having vastly different metabolisms. Continued exposure to insults, including chronic stress with advancing age, increases proteostatic burden and reduces the fidelity of the degradation machineries including the ubiquitin-proteasome and the autophagy-lysosome systems that recognize and remove damaged proteins. This "double jeopardy" results in an exponential accumulation of cytotoxic proteins with advancing age. We conclude with a discussion of the challenges in maintaining an appropriate balance of protein synthesis and degradation pathways, and suggest that harnessing proteostatic capacities should provide new opportunities to design interventions for attenuating age-related eye diseases before they limit sight.
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Affiliation(s)
- Jasper Weinberg
- Laboratory for Nutrition and Vision Research, USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, 02111, USA
| | - Mohita Gaur
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Anand Swaroop
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Allen Taylor
- Laboratory for Nutrition and Vision Research, USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, 02111, USA.
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7
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Intartaglia D, Giamundo G, Conte I. Autophagy in the retinal pigment epithelium: a new vision and future challenges. FEBS J 2022; 289:7199-7212. [PMID: 33993621 PMCID: PMC9786786 DOI: 10.1111/febs.16018] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 04/07/2021] [Accepted: 05/12/2021] [Indexed: 01/13/2023]
Abstract
The retinal pigment epithelium (RPE) is a highly specialized monolayer of polarized, pigmented epithelial cells that resides between the vessels of the choriocapillaris and the neural retina. The RPE is essential for the maintenance and survival of overlying light-sensitive photoreceptors, as it participates in the formation of the outer blood-retinal barrier, phagocytosis, degradation of photoreceptor outer segment (POS) tips, maintenance of the retinoid cycle, and protection against light and oxidative stress. Autophagy is an evolutionarily conserved 'self-eating' process, designed to maintain cellular homeostasis. The daily autophagy demands in the RPE require precise gene regulation for the digestion and recycling of intracellular and POS components in lysosomes in response to light and stress conditions. In this review, we discuss selective autophagy and focus on the recent advances in our understanding of the mechanism of cell clearance in the RPE for visual function. Understanding how this catabolic process is regulated by both transcriptional and post-transcriptional mechanisms in the RPE will promote the recognition of pathological pathways in genetic disease and shed light on potential therapeutic strategies to treat visual impairments in patients with retinal disorders associated with lysosomal dysfunction.
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Affiliation(s)
| | | | - Ivan Conte
- Telethon Institute of Genetics and MedicinePozzuoli (Naples)Italy,Department of BiologyUniversity of Naples Federico IINaplesItaly
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8
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Sridevi Gurubaran I, Hytti M, Kaarniranta K, Kauppinen A. Epoxomicin, a Selective Proteasome Inhibitor, Activates AIM2 Inflammasome in Human Retinal Pigment Epithelium Cells. Antioxidants (Basel) 2022; 11:antiox11071288. [PMID: 35883779 PMCID: PMC9311580 DOI: 10.3390/antiox11071288] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/26/2022] [Accepted: 06/26/2022] [Indexed: 02/04/2023] Open
Abstract
Emerging evidence suggests that the intracellular clearance system plays a vital role in maintaining homeostasis and in regulating oxidative stress and inflammation in retinal pigment epithelium (RPE) cells. Dysfunctional proteasomes and autophagy in RPE cells have been associated with the pathogenesis of age-related macular degeneration. We have previously shown that the inhibition of proteasomes using MG-132 activates the NLR family pyrin domain containing 3 (NLRP3) inflammasome in human RPE cells. However, MG-132 is a non-selective proteasome inhibitor. In this study, we used the selective proteasome inhibitor epoxomicin to study the effect of non-functional intracellular clearance systems on inflammasome activation. Our data show that epoxomicin-induced proteasome inhibition promoted both nicotinamide adenine dinucleotide phosphate oxidase and mitochondria-mediated oxidative stress and release of mitochondrial DNA to the cytosol, which resulted in potassium efflux-dependent absence in melanoma 2 (AIM2) inflammasome activation and subsequent interleukin-1β secretion in ARPE-19 cells. The non-specific proteasome inhibitor MG-132 activated both NLRP3 and AIM2 inflammasomes and oxidative stress predominated as the activation mechanism, but modest potassium efflux was also detected. Collectively, our data suggest that a selective proteasome inhibitor is a potent inflammasome activator in human RPE cells and emphasize the role of the AIM2 inflammasome in addition to the more commonly known NLRP3 inflammasome.
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Affiliation(s)
- Iswariyaraja Sridevi Gurubaran
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, 70210 Kuopio, Finland; (I.S.G.); (K.K.)
| | - Maria Hytti
- Immuno-Ophthalmology, School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70210 Kuopio, Finland;
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, 70210 Kuopio, Finland; (I.S.G.); (K.K.)
- Department of Ophthalmology, University of Eastern Finland, 70211 Kuopio, Finland
- Department of Ophthalmology, Kuopio University Hospital, 70029 Kuopio, Finland
| | - Anu Kauppinen
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, 70210 Kuopio, Finland; (I.S.G.); (K.K.)
- Immuno-Ophthalmology, School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70210 Kuopio, Finland;
- Correspondence:
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9
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Prokai-Tatrai K, Zaman K, Nguyen V, De La Cruz DL, Prokai L. Proteomics-Based Retinal Target Engagement Analysis and Retina-Targeted Delivery of 17β-Estradiol by the DHED Prodrug for Ocular Neurotherapy in Males. Pharmaceutics 2021; 13:1392. [PMID: 34575465 PMCID: PMC8466286 DOI: 10.3390/pharmaceutics13091392] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/26/2021] [Accepted: 08/27/2021] [Indexed: 12/21/2022] Open
Abstract
We examined the impact of 17β-estradiol (E2) eye drops on the modulation of the proteome profile in the male rat retina. With discovery-driven proteomics, we have identified proteins that were regulated by our treatment. These proteins were assembled to several bioinformatics-based networks implicating E2's beneficial effects on the male rat retina in a broad context of ocular neuroprotection including the maintenance of retinal homeostasis, facilitation of efficient disposal of damaged proteins, and mitochondrial respiratory chain biogenesis. We have also shown for the first time that the hormone's beneficial effects on the male retina can be constrained to this target site by treatment with the bioprecursor prodrug, DHED. A large concentration of E2 was produced after DHED eye drops not only in male rat retinae but also in those of rabbits. However, DHED treatment did not increase circulating E2 levels, thereby ensuring therapeutic safety in males. Targeted proteomics focusing on selected biomarkers of E2's target engagement further confirmed the prodrug's metabolism to E2 in the male retina and indicated that the retinal impact of DHED treatment was identical to that of the direct E2 treatment. Altogether, our study shows the potential of topical DHED therapy for an efficacious and safe protection of the male retina without the unwanted hormonal side-effects associated with current estrogen therapies.
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Affiliation(s)
- Katalin Prokai-Tatrai
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA; (K.Z.); (V.N.); (D.L.D.L.C.); (L.P.)
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10
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The Glyoxalase System in Age-Related Diseases: Nutritional Intervention as Anti-Ageing Strategy. Cells 2021; 10:cells10081852. [PMID: 34440621 PMCID: PMC8393707 DOI: 10.3390/cells10081852] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 07/09/2021] [Accepted: 07/15/2021] [Indexed: 12/19/2022] Open
Abstract
The glyoxalase system is critical for the detoxification of advanced glycation end-products (AGEs). AGEs are toxic compounds resulting from the non-enzymatic modification of biomolecules by sugars or their metabolites through a process called glycation. AGEs have adverse effects on many tissues, playing a pathogenic role in the progression of molecular and cellular aging. Due to the age-related decline in different anti-AGE mechanisms, including detoxifying mechanisms and proteolytic capacities, glycated biomolecules are accumulated during normal aging in our body in a tissue-dependent manner. Viewed in this way, anti-AGE detoxifying systems are proposed as therapeutic targets to fight pathological dysfunction associated with AGE accumulation and cytotoxicity. Here, we summarize the current state of knowledge related to the protective mechanisms against glycative stress, with a special emphasis on the glyoxalase system as the primary mechanism for detoxifying the reactive intermediates of glycation. This review focuses on glyoxalase 1 (GLO1), the first enzyme of the glyoxalase system, and the rate-limiting enzyme of this catalytic process. Although GLO1 is ubiquitously expressed, protein levels and activities are regulated in a tissue-dependent manner. We provide a comparative analysis of GLO1 protein in different tissues. Our findings indicate a role for the glyoxalase system in homeostasis in the eye retina, a highly oxygenated tissue with rapid protein turnover. We also describe modulation of the glyoxalase system as a therapeutic target to delay the development of age-related diseases and summarize the literature that describes the current knowledge about nutritional compounds with properties to modulate the glyoxalase system.
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11
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Piedade WP, Famulski JK. E3 ubiquitin ligase-mediated regulation of vertebrate ocular development; new insights into the function of SIAH enzymes. Biochem Soc Trans 2021; 49:327-340. [PMID: 33616626 PMCID: PMC7924998 DOI: 10.1042/bst20200613] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/22/2021] [Accepted: 01/25/2021] [Indexed: 01/18/2023]
Abstract
Developmental regulation of the vertebrate visual system has been a focus of investigation for generations as understanding this critical time period has direct implications on our understanding of congenital blinding disease. The majority of studies to date have focused on transcriptional regulation mediated by morphogen gradients and signaling pathways. However, recent studies of post translational regulation during ocular development have shed light on the role of the ubiquitin proteasome system (UPS). This rather ubiquitous yet highly diverse system is well known for regulating protein function and localization as well as stability via targeting for degradation by the 26S proteasome. Work from many model organisms has recently identified UPS activity during various milestones of ocular development including retinal morphogenesis, retinal ganglion cell function as well as photoreceptor homeostasis. In particular work from flies and zebrafish has highlighted the role of the E3 ligase enzyme family, Seven in Absentia Homologue (Siah) during these events. In this review, we summarize the current understanding of UPS activity during Drosophila and vertebrate ocular development, with a major focus on recent findings correlating Siah E3 ligase activity with two major developmental stages of vertebrate ocular development, retinal morphogenesis and photoreceptor specification and survival.
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12
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Mishra R, Joshi V, Upadhyay A, Amanullah A, Dubey AR, Singh S, Dubey VK, Poluri KM, Jana NR, Mishra A. LRSAM1 E3 ubiquitin ligase promotes proteasomal clearance of E6-AP protein. Cell Signal 2020; 77:109836. [PMID: 33207262 DOI: 10.1016/j.cellsig.2020.109836] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 11/12/2020] [Accepted: 11/12/2020] [Indexed: 01/19/2023]
Abstract
Numerous proteins participate and actively contribute to the various cellular mechanisms, where several of them are crucial for regular metabolism, including survival. Thus, to maintain optimal cellular physiology, cells govern protein quality control functions with the assistance of comprehensive actions of molecular chaperones, the ubiquitin-proteasome system, and autophagy. In the ubiquitin-proteasome pathway, few quality control E3 ubiquitin ligases actively participate against misfolded protein aggregation generated via stress conditions. But how these quality control E3s active expression levels returned to basal levels when cells achieved re-establishment of proteostasis is still poorly understood. Our current study demonstrated that LRSAM1 E3 ubiquitin ligase promotes the proteasomal degradation of quality control E3 ubiquitin ligase E6-AP. We have observed the co-localization and recruitment of LRSAM1 with E6-AP protein and noticed that LRSAM1 induces the endogenous turnover of E6-AP. Partial depletion of LRSAM1 elevates the levels of E6-AP and affects overall cell cycle regulatory proteins (p53 and p27) expression, including the rate of cellular proliferation. The current finding also provides an excellent opportunity to better understand the basis of the E6-AP associated pathomechanism of Angelman Syndrome disorder. Additionally, this study touches upon the novel potential molecular strategy to regulate the levels of one quality control E3 ubiquitin ligase with another E3 ubiquitin ligase and restore proteostasis and provide a possible therapeutic approach against abnormal protein aggregation diseases.
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Affiliation(s)
- Ribhav Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Rajasthan 342037, India
| | - Vibhuti Joshi
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Rajasthan 342037, India
| | - Arun Upadhyay
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Rajasthan 342037, India
| | - Ayeman Amanullah
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Rajasthan 342037, India
| | - Ankur Rakesh Dubey
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Rajasthan 342037, India
| | - Sarika Singh
- Department of Neuroscience and Ageing Biology and Division of Toxicology and Experimental Medicine, CSIR-Central Drug Research Institute, Lucknow 226031, UP, India
| | - Vikash Kumar Dubey
- School of Biochemical Engineering, Indian Institute of Technology BHU, Varanasi 221005, India
| | - Krishna Mohan Poluri
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India
| | - Nihar Ranjan Jana
- School of Bioscience Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Amit Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Rajasthan 342037, India.
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13
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An evaluation of the effects of probiotics on tumoral necrosis factor (TNF-α) signaling and gene expression. Cytokine Growth Factor Rev 2020; 57:27-38. [PMID: 33162326 DOI: 10.1016/j.cytogfr.2020.10.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 10/06/2020] [Accepted: 10/09/2020] [Indexed: 12/16/2022]
Abstract
The search for functional foods containing probiotics has been growing due to numerous benefits they provide to health, such as modulation of the immune system and of the anti-inflammatory activity by inhibiting the release of pro-inflammatory cytokines, such as TNF-α. However, the mechanisms of actions of the probiotics responsible for this inhibition have not been completely explained so far. A better understanding of the interaction between probiotics and cell signaling pathways related to inflammatory processes shall help to prevent inflammatory bowel diseases. Therefore, the aim of this revision is to help understand the mechanisms of action of probiotics in cell signaling pathways that regulate TNF-α expression. Probiotics might act at different points of the MAPK pathway, on NF-kB, on proteasome activity, on Toll-like receptors, and on their regulators and stimuli. The present revision reaches the conclusion that probiotics act through multiple mechanisms, especially by inhibiting IkB phosphorylation and degradation, thus preventing the translocation of NF-kB. Effects are also shown to be strain-specific, and probiotics of the genus Lactobacillus are proved to play and essential role in anti-inflammatory activity.
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14
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Aragonès G, Rowan S, G Francisco S, Yang W, Weinberg J, Taylor A, Bejarano E. Glyoxalase System as a Therapeutic Target against Diabetic Retinopathy. Antioxidants (Basel) 2020; 9:antiox9111062. [PMID: 33143048 PMCID: PMC7692619 DOI: 10.3390/antiox9111062] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/25/2020] [Accepted: 10/27/2020] [Indexed: 12/14/2022] Open
Abstract
Hyperglycemia, a defining characteristic of diabetes, combined with oxidative stress, results in the formation of advanced glycation end products (AGEs). AGEs are toxic compounds that have adverse effects on many tissues including the retina and lens. AGEs promote the formation of reactive oxygen species (ROS), which, in turn, boost the production of AGEs, resulting in positive feedback loops, a vicious cycle that compromises tissue fitness. Oxidative stress and the accumulation of AGEs are etiologically associated with the pathogenesis of multiple diseases including diabetic retinopathy (DR). DR is a devastating microvascular complication of diabetes mellitus and the leading cause of blindness in working-age adults. The onset and development of DR is multifactorial. Lowering AGEs accumulation may represent a potential therapeutic approach to slow this sight-threatening diabetic complication. To set DR in a physiological context, in this review we first describe relations between oxidative stress, formation of AGEs, and aging in several tissues of the eye, each of which is associated with a major age-related eye pathology. We summarize mechanisms of AGEs generation and anti-AGEs detoxifying systems. We specifically feature the potential of the glyoxalase system in the retina in the prevention of AGEs-associated damage linked to DR. We provide a comparative analysis of glyoxalase activity in different tissues from wild-type mice, supporting a major role for the glyoxalase system in the detoxification of AGEs in the retina, and present the manipulation of this system as a therapeutic strategy to prevent the onset of DR.
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Affiliation(s)
- Gemma Aragonès
- Laboratory for Nutrition and Vision Research, USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02155, USA; (G.A.); (S.R.); (S.G.F.); (W.Y.); (J.W.)
| | - Sheldon Rowan
- Laboratory for Nutrition and Vision Research, USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02155, USA; (G.A.); (S.R.); (S.G.F.); (W.Y.); (J.W.)
- Department of Ophthalmology, Tufts University School of Medicine, Boston, MA 02155, USA
- Friedman School of Nutrition and Science Policy, Tufts University, Boston, MA 02155, USA
| | - Sarah G Francisco
- Laboratory for Nutrition and Vision Research, USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02155, USA; (G.A.); (S.R.); (S.G.F.); (W.Y.); (J.W.)
| | - Wenxin Yang
- Laboratory for Nutrition and Vision Research, USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02155, USA; (G.A.); (S.R.); (S.G.F.); (W.Y.); (J.W.)
| | - Jasper Weinberg
- Laboratory for Nutrition and Vision Research, USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02155, USA; (G.A.); (S.R.); (S.G.F.); (W.Y.); (J.W.)
| | - Allen Taylor
- Laboratory for Nutrition and Vision Research, USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02155, USA; (G.A.); (S.R.); (S.G.F.); (W.Y.); (J.W.)
- Department of Ophthalmology, Tufts University School of Medicine, Boston, MA 02155, USA
- Friedman School of Nutrition and Science Policy, Tufts University, Boston, MA 02155, USA
- Correspondence: (A.T.); (E.B.); Tel.: +617-556-3156 (A.T.)
| | - Eloy Bejarano
- Laboratory for Nutrition and Vision Research, USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02155, USA; (G.A.); (S.R.); (S.G.F.); (W.Y.); (J.W.)
- Universidad Cardenal Herrera-CEU, CEU Universities, 46115 Valencia, Spain
- Correspondence: (A.T.); (E.B.); Tel.: +617-556-3156 (A.T.)
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15
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Chang YC, Lin CW, Chang YS, Chen PH, Li CY, Wu WC, Kao YH. Monounsaturated oleic acid modulates autophagy flux and upregulates angiogenic factor production in human retinal pigment epithelial ARPE-19 cells. Life Sci 2020; 259:118391. [PMID: 32891610 DOI: 10.1016/j.lfs.2020.118391] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 08/25/2020] [Accepted: 09/02/2020] [Indexed: 12/12/2022]
Abstract
AIMS Dyslipidemia-associated diabetic retinopathy is featured by macular edema and retinal angiogenesis. This study investigated the in vitro lipotoxicity of free fatty acids and their modulatory roles in regulation of autophagy and angiogenic factor production in cultured human retinal pigment epithelium (RPE) ARPE-19 cells. MAIN METHODS ARPE-19 cells were exposed to monounsaturated oleic acid (OA), saturated palmitic acid (PA), or both. Cell viability, cell cycle distribution, migration, and autophagy of the treated cells were monitored. Angiogenic factor production was determined by RT-qPCR and ELISA. KEY FINDINGS OA, but not PA, at doses higher than 500 μM significantly induced cytostasis and lipotoxicity in ARPE-19 cells. OA exposure not only markedly enhanced autophagy flux, but also enhanced cell migration, while PA suppressed motility of RPE cells. Meanwhile, OA stimulated de novo synthesis of angiogenic factors including VEGF and bFGF in ARPE-19 cells. Mechanistically, OA treatment stimulated not only AMPK/mTOR/p70S6K signaling, but also induced hyperphosphorylation of MAPK pathway mediators, including ERK, JNK and p38 MAPK, as well as NF-κB activation. Kinase inhibition assays showed that blockade of PI3K/Akt, MAPK and NF-κB pathways prevented the OA-upregulated VEGF transcription and its peptide release. Comparatively, only NF-κB inhibition significantly suppressed bFGF peptide release from ARPE-19 cells. SIGNIFICANCE Out findings support the OA-exhibited cytostasis, autophagy modulation and angiogenic factor production in RPE cells. This study sheds light on the interrelationship between metabolic disorder and retinopathy and provides molecular strategies for preventing and treating choroidal neovascularization in diabetic retinopathy.
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Affiliation(s)
- Yo-Chen Chang
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Ophthalmology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Ophthalmology, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chia-Wei Lin
- Department of Ophthalmology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Yuh-Shin Chang
- Department of Ophthalmology, Chi Mei Medical Center, Tainan, Taiwan; Graduate Institute of Medical Science, College of Health Science, Gang Jung Christian University, Tainan, Taiwan
| | - Po-Han Chen
- Department of Medical Research, E-Da Hospital, Kaohsiung, Taiwan
| | - Chia-Yang Li
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Wen-Chuan Wu
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Ophthalmology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
| | - Ying-Hsien Kao
- Department of Medical Research, E-Da Hospital, Kaohsiung, Taiwan.
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16
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Mohanty V, Pinto SM, Subbannayya Y, Najar MA, Murthy KB, Prasad TSK, Murthy KR. Digging Deeper for the Eye Proteome in Vitreous Substructures: A High-Resolution Proteome Map of the Normal Human Vitreous Base. ACTA ACUST UNITED AC 2020; 24:379-389. [DOI: 10.1089/omi.2020.0020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Varshasnata Mohanty
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, India
| | - Sneha M. Pinto
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, India
| | - Yashwanth Subbannayya
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, India
| | - Mohd. Altaf Najar
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, India
| | - Kalpana Babu Murthy
- Department of vitreo retina, Vittala International Institute of Ophthalmology, Bangalore, India
- Department of vitreo retina, Prabha Eye Clinic and Research Centre, Bangalore, India
| | | | - Krishna R. Murthy
- Department of vitreo retina, Vittala International Institute of Ophthalmology, Bangalore, India
- Department of vitreo retina, Prabha Eye Clinic and Research Centre, Bangalore, India
- Institute of Bioinformatics, International Technology Park, Bangalore, India
- Manipal Academy of Higher Education, Manipal, India
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17
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Wu H, Sun H, He Z, Chen X, Li Y, Zhao X, Kong W, Kong W. The effect and mechanism of 19S proteasome PSMD11/Rpn6 subunit in D-Galactose induced mimetic aging models. Exp Cell Res 2020; 394:112093. [PMID: 32450067 DOI: 10.1016/j.yexcr.2020.112093] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 05/14/2020] [Accepted: 05/16/2020] [Indexed: 11/30/2022]
Abstract
Regulating proteasome activity is a potent therapeutic aspect of age-related hearing loss, which has been proven to protect neurons from age-related damaging. PSMD11, subunit of the 19S proteasome regulatory particle, is known to mainly up-regulate proteasome activity and prolong aging. However, the mechanism of PSMD11 in age-related hearing loss has not been deeply explored. In the present study, we explore the function and mechanism of PSMD11 protecting neurons in d-Galactose (D-Gal) mimetic aging models. Age-related pathologies were detected by Taq-PCR, ABR, Transmission electron microscopy, toluidine blue and β-galactosidase staining. The relative expressions of the proteins were explored by Western blotting, oxyblot, immunoprecipitation and immunofluorescence. Flow cytometry was used to manifest the oxidative state. We discovered that proteasome activity was impaired with aging, and that ROS and toxic protein accumulated in D-Gal induced aging models. PSMD11 changed with aging, and was associated with the metabolism of proteasome activity in the D-Gal treated models. Moreover, the knockdown or overexpression of PSMD11 was sufficient to change the oxidative state caused by D-Gal. Our results also demonstrated that PSMD11 could bond to AMPKα1/2 in the auditory cortex and PC12 cells, and AMPKα2 but not AMPKα1 was efficient to regulate the function of PSMD11. Deeper insights into the mechanisms of regulating PSMD11 for the anti-aging process are needed, and may offer novel therapeutic methods for central presbycusis.
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Affiliation(s)
- Han Wu
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
| | - Haiying Sun
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
| | - Zuhong He
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
| | - Xi Chen
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
| | - Yongqin Li
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
| | - Xueyan Zhao
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
| | - Wen Kong
- Departments of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430022, China.
| | - Weijia Kong
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
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18
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Xia H, Zhang Q, Shen Y, Bai Y, Ma X, Zhang B, Qi Y, Zhang J, Hu Q, Du W, Zhu L, Zhou P, Wang B, Xu H, Huang L, Li X. ube3d, a New Gene Associated with Age-Related Macular Degeneration, Induces Functional Changes in Both In Vivo and In Vitro Studies. MOLECULAR THERAPY-NUCLEIC ACIDS 2020; 20:217-230. [PMID: 32200270 PMCID: PMC7090285 DOI: 10.1016/j.omtn.2020.02.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 11/27/2019] [Accepted: 02/19/2020] [Indexed: 10/31/2022]
Abstract
Neovascular age-related macular degeneration (AMD) is characterized by the formation of choroidal neovascularization, which is responsible for more than 80% of cases of severe vision loss. Ubiquitin protein ligase E3D (UBE3D) gene missense has been proven to be associated with neovascular AMD in the East Asian population based on our previous study. In vivo, we explored the role of ube3d in eye development and the mechanisms underlying the development of neovascular AMD in a zebrafish model. In vitro, we investigated the function and mechanism of ube3d in oxidative damage in human retinal pigment epithelium (hRPE) cells. The ube3d gene was knocked down in zebrafish in our experiments, and rescue of ube3d morphants was also performed. We observed the zebrafish model at the molecular level and functional and morphological changes in vivo. Lentivirus-based gene transfer technology was used to overexpress/knockdown ube3d expression in hRPE cells in vitro. hRPE oxidative damage was induced by tert-butyl hydroperoxide (t-TBH). Cell proliferation and migration were assessed. Quantitative real-time PCR and western blot were used to measure the expression levels of UBE3D and CyclinB1. Abnormal eye development was found in zebrafish in this study, including small eyes, delayed retinal development, delayed retrograde melanosome transport, and reduced dark-induced hyper-locomotor activity under light-off conditions. In addition, increased angiogenesis was observed in ube3d morphants. A negative correlation between UBE3D and CyclinB1 was observed. Low UBE3D expression can promote oxidative damage and inflammatory reactions. UBE3D and autophagy have a synergetic effect on anti-oxidative damage. These findings indicate that ube3d may play an important role in the pathogenesis of AMD by affecting retinal development, oxidative damage, and autophagy.
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Affiliation(s)
- Huika Xia
- Department of Ophthalmology, Peking University People's Hospital, Beijing 100044, China; Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Peking University People's Hospital, Beijing 100044, China; Department of Ophthalmology, Hebei General Hospital, Shijiazhuang, Hebei 050051, China
| | - Qi Zhang
- Department of Ophthalmology, Peking University People's Hospital, Beijing 100044, China; Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Peking University People's Hospital, Beijing 100044, China
| | - Yan Shen
- Key Laboratory of Cell Proliferation and Differentiation of Ministry of Education, College of Life Sciences, Peking University, Beijing 100871, China
| | - Yujing Bai
- Department of Ophthalmology, Peking University People's Hospital, Beijing 100044, China; Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Peking University People's Hospital, Beijing 100044, China
| | - Xiaoyun Ma
- Department of Ophthalmology, Shanghai University of Medicine & Health Sciences Affiliated Zhoupu Hospital, Shanghai 201318, China
| | - Bo Zhang
- Key Laboratory of Cell Proliferation and Differentiation of Ministry of Education, College of Life Sciences, Peking University, Beijing 100871, China
| | - Yun Qi
- Department of Ophthalmology, Peking University People's Hospital, Beijing 100044, China; Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Peking University People's Hospital, Beijing 100044, China
| | - Jingjing Zhang
- Department of Ophthalmology, Peking University People's Hospital, Beijing 100044, China; Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Peking University People's Hospital, Beijing 100044, China
| | - Qinrui Hu
- Department of Ophthalmology, Peking University People's Hospital, Beijing 100044, China; Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Peking University People's Hospital, Beijing 100044, China
| | - Wei Du
- Department of Ophthalmology, Peking University People's Hospital, Beijing 100044, China; Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Peking University People's Hospital, Beijing 100044, China
| | - Li Zhu
- Department of Ophthalmology, Peking University People's Hospital, Beijing 100044, China; Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Peking University People's Hospital, Beijing 100044, China
| | - Peng Zhou
- Parkway Health Hongqiao Medical Center, Shanghai 201101, China
| | - Bin Wang
- Xiamen Eye Centre of Xiamen University & Eye Institute of Xiamen University, Xiamen, Fujian 361000, China
| | - Hui Xu
- Department of Ophthalmology, Peking University People's Hospital, Beijing 100044, China; Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Peking University People's Hospital, Beijing 100044, China
| | - Lvzhen Huang
- Department of Ophthalmology, Peking University People's Hospital, Beijing 100044, China; Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Peking University People's Hospital, Beijing 100044, China.
| | - Xiaoxin Li
- Department of Ophthalmology, Peking University People's Hospital, Beijing 100044, China; Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Peking University People's Hospital, Beijing 100044, China; Xiamen Eye Centre of Xiamen University & Eye Institute of Xiamen University, Xiamen, Fujian 361000, China.
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19
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Xi M, Chen Y, Yang H, Xu H, Du K, Wu C, Xu Y, Deng L, Luo X, Yu L, Wu Y, Gao X, Cai T, Chen B, Shen R, Sun H. Small molecule PROTACs in targeted therapy: An emerging strategy to induce protein degradation. Eur J Med Chem 2019; 174:159-180. [PMID: 31035238 DOI: 10.1016/j.ejmech.2019.04.036] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 04/13/2019] [Accepted: 04/13/2019] [Indexed: 01/01/2023]
Abstract
Inhibitors and nucleic acid based techniques were two main approaches to interfere with protein signaling and respective cascade in the past. Until recently, a new class of small molecules named proteolysis-targeting chimeras (PROTACs) have emerged. Each contains a target warhead, a linker and an E3 ligand. These bifunctional molecules recruit E3 ligases and target specific proteins for degradation via the ubiquitin (Ub) proteasome system (UPS). The degradation provides several advantages over inhibition in potency, selectivity and drug resistance. Thus, a variety of small molecule PROTACs have been discovered so far. In this review, we summarize the biological mechanism, advantages and recent progress of PROTACs, trying to offer an outlook in development of drugs targeting degradation in future.
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Affiliation(s)
- Meiyang Xi
- College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Yi Chen
- College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Hongyu Yang
- Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing, 210009, China
| | - Huiting Xu
- College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Kui Du
- College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Chunlei Wu
- College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Yanfei Xu
- College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Liping Deng
- College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Xiang Luo
- College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Lemao Yu
- College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Yonghua Wu
- College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Xiaozhong Gao
- College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Tao Cai
- College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Bin Chen
- College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Runpu Shen
- College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China.
| | - Haopeng Sun
- Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing, 210009, China.
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20
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Zernii EY, Nazipova AA, Nemashkalova EL, Kazakov AS, Gancharova OS, Serebryakova MV, Tikhomirova NK, Baksheeva VE, Vladimirov VI, Zinchenko DV, Philippov PP, Senin II, Permyakov SE. Light-Induced Thiol Oxidation of Recoverin Affects Rhodopsin Desensitization. Front Mol Neurosci 2019; 11:474. [PMID: 30666186 PMCID: PMC6330308 DOI: 10.3389/fnmol.2018.00474] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 12/05/2018] [Indexed: 02/03/2023] Open
Abstract
The excessive light illumination of mammalian retina is known to induce oxidative stress and photoreceptor cell death linked to progression of age-related macular degeneration. The photochemical damage of photoreceptors is suggested to occur via two apoptotic pathways that involve either excessive rhodopsin activation or constitutive phototransduction, depending on the light intensity. Both pathways are dramatically activated in the absence of rhodopsin desensitization by GRK1. Previously, we have shown that moderate illumination (halogen lamp, 1,500 lx, 1–5 h) of mammalian eyes provokes disulfide dimerization of recoverin, a calcium-dependent regulator of GRK1. Here, we demonstrate under in vivo conditions that both moderate long-term (metal halide lamp, 2,500 lx, 14 h, rat model) and intense short-term (halogen lamp, 30,000 lx for 3 h, rabbit model) illumination of the mammalian retina are accompanied by accumulation of disulfide dimer of recoverin. Furthermore, in the second case we reveal alternatively oxidized derivatives of the protein, apparently including its monomer with sulfinic group. Histological data indicate that thiol oxidation of recoverin precedes apoptosis of photoreceptors. Both disulfide dimer and oxidized monomer (or oxidation mimicking C39D mutant) of recoverin exhibit lowered α-helical content and thermal stability of their apo-forms, as well as increased Ca2+ affinity. Meanwhile, the oxidized monomer and C39D mutant of recoverin demonstrate impaired ability to bind photoreceptor membranes and regulate GRK1, whereas disulfide dimer exhibits notably improved membrane binding and GRK1 inhibition in absence of Ca2+. The latter effect is expected to slow down rhodopsin desensitization in the light, thereby favoring support of the light-induced oxidative stress, ultimately leading to photoreceptor apoptosis. Overall, the intensity and duration of illumination of the retina affect thiol oxidation of recoverin likely contributing to propagation of the oxidative stress and photoreceptor damage.
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Affiliation(s)
- Evgeni Yu Zernii
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.,Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia
| | - Aliya A Nazipova
- Institute for Biological Instrumentation of the Russian Academy of Sciences, Pushchino, Russia
| | | | - Alexey S Kazakov
- Institute for Biological Instrumentation of the Russian Academy of Sciences, Pushchino, Russia
| | - Olga S Gancharova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.,Institute for Regenerative Medicine, Sechenov First Moscow State Medical University, Moscow, Russia
| | - Marina V Serebryakova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Natalya K Tikhomirova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Viktoriia E Baksheeva
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Vasiliy I Vladimirov
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Pushchino, Russia
| | - Dmitry V Zinchenko
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Pushchino, Russia
| | - Pavel P Philippov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Ivan I Senin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Sergei E Permyakov
- Institute for Biological Instrumentation of the Russian Academy of Sciences, Pushchino, Russia
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21
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Bejarano E, Taylor A. Too sweet: Problems of protein glycation in the eye. Exp Eye Res 2018; 178:255-262. [PMID: 30145354 DOI: 10.1016/j.exer.2018.08.017] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 08/03/2018] [Accepted: 08/22/2018] [Indexed: 01/06/2023]
Abstract
Laboratory and epidemiological data indicate that high blood sugar levels and/or consuming high glycemia diets are linked to multiple age-related diseases, including age-related macular degeneration, cataract, Parkinson's disease, Alzheimer's disease, diabetic retinopathy, and, apparently glaucoma. High concentrations of blood sugar and perturbations of the systems that regulate blood sugar lead to the accumulation of advanced-glycation end products (AGEs). AGEs are toxic compounds that are formed from the combination of sugars and their metabolites with biomolecules in a non-enzymatic biochemical reaction called glycation. In vitro and in vivo data indicate that high sugar consumption is associated with accumulation of AGEs in a variety of human tissues. Hyperglycemia, along with an oxidative environment and limited cell proliferation in many ocular tissues, encourages formation and precludes dilution of AGEs and associated damage by cell division. These circumstances make many eye tissues vulnerable to glycation-derived damage. Here, we summarize research regarding glycation-induced ocular tissue dysfunction and its contribution to the onset and development of eye disorders. We also discuss how management of carbohydrate nutrition may provide a low-cost way to ameliorate the progression of AGEs-related diseases, including age related macular degeneration and some cataracts, as they do for cardiovascular disease and diabetes.
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Affiliation(s)
- Eloy Bejarano
- Laboratory for Nutrition and Vision Research, USDA Human Nutrition Research Center on Aging, Tufts University, 711 Washington St, Boston, MA, 02111, USA.
| | - Allen Taylor
- Laboratory for Nutrition and Vision Research, USDA Human Nutrition Research Center on Aging, Tufts University, 711 Washington St, Boston, MA, 02111, USA.
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Hyttinen JMT, Viiri J, Kaarniranta K, Błasiak J. Mitochondrial quality control in AMD: does mitophagy play a pivotal role? Cell Mol Life Sci 2018; 75:2991-3008. [PMID: 29777261 PMCID: PMC11105454 DOI: 10.1007/s00018-018-2843-7] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 04/25/2018] [Accepted: 05/16/2018] [Indexed: 01/05/2023]
Abstract
Age-related macular degeneration (AMD) is the predominant cause of visual loss in old people in the developed world, whose incidence is increasing. This disease is caused by the decrease in macular function, due to the degeneration of retinal pigment epithelium (RPE) cells. The aged retina is characterised by increased levels of reactive oxygen species (ROS), impaired autophagy, and DNA damage that are linked to AMD pathogenesis. Mitophagy, a mitochondria-specific type of autophagy, is an essential part of mitochondrial quality control, the collective mechanism responsible for this organelle's homeostasis. The abundance of ROS, DNA damage, and the excessive energy consumption in the ageing retina all contribute to the degeneration of RPE cells and their mitochondria. We discuss the role of mitophagy in the cell and argue that its impairment may play a role in AMD pathogenesis. Thus, mitophagy as a potential therapeutic target in AMD and other degenerative diseases is as well explored.
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Affiliation(s)
- Juha M T Hyttinen
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland.
| | - Johanna Viiri
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland
- Department of Ophthalmology, Kuopio University Hospital, P.O. Box 100, 70029 KYS, Kuopio, Finland
| | - Janusz Błasiak
- Department of Molecular Genetics, University of Łódź, Pomorska 141/143, 90-236, Łódź, Poland
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Fernandez-Godino R, Pierce EA. C3a triggers formation of sub-retinal pigment epithelium deposits via the ubiquitin proteasome pathway. Sci Rep 2018; 8:9679. [PMID: 29946065 PMCID: PMC6018664 DOI: 10.1038/s41598-018-28143-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Accepted: 06/15/2018] [Indexed: 01/25/2023] Open
Abstract
The mechanisms that connect complement system activation and basal deposit formation in early stages of age-related macular degeneration (AMD) are insufficiently understood, which complicates the design of efficient therapies to prevent disease progression. Using human fetal (hf) retinal pigment epithelial (RPE) cells, we have established an in vitro model to investigate the effect of complement C3a on RPE cells and its role in the formation of sub-RPE deposits. The results of these studies revealed that C3a produced after C3 activation is sufficient to induce the formation of sub-RPE deposits via complement-driven proteasome inhibition. C3a binds the C3a receptor (C3aR), stimulates deposition of collagens IV and VI underneath the RPE, and impairs the extracellular matrix (ECM) turnover by increased MMP-2 activity, all mediated by downregulation of the ubiquitin proteasome pathway (UPP). The formation of basal deposits can be prevented by the addition of a C3aR antagonist, which restores the UPP activity and ECM turnover. These findings indicate that the cell-based model can be used to test potential therapeutic agents in vitro. The data suggest that modulation of C3aR-mediated events could be a therapeutic approach for treatment of early AMD.
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Affiliation(s)
- Rosario Fernandez-Godino
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, 02114, USA.
| | - Eric A Pierce
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, 02114, USA
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Elmasry K, Ibrahim AS, Saleh H, Elsherbiny N, Elshafey S, Hussein KA, Al-Shabrawey M. Role of endoplasmic reticulum stress in 12/15-lipoxygenase-induced retinal microvascular dysfunction in a mouse model of diabetic retinopathy. Diabetologia 2018; 61:1220-1232. [PMID: 29468369 PMCID: PMC5878142 DOI: 10.1007/s00125-018-4560-z] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 12/20/2017] [Indexed: 12/14/2022]
Abstract
AIMS/HYPOTHESIS Our earlier studies have established the role of 12/15-lipoxygenase (LO) in mediating the inflammatory reaction in diabetic retinopathy. However, the exact mechanism is still unclear. The goal of the current study was to identify the potential role of endoplasmic reticulum (ER) stress as a major cellular stress response in the 12/15-LO-induced retinal changes in diabetic retinopathy. METHODS We used in vivo and in vitro approaches. For in vivo studies, experimental diabetes was induced in wild-type (WT) mice and 12/15-Lo (also known as Alox15) knockout mice (12/15-Lo-/-); ER stress was then evaluated after 12-14 weeks of diabetes. We also tested the effect of intravitreal injection of 12-hydroxyeicosatetraenoic acid (HETE) on retinal ER stress in WT mice and in mice lacking the catalytic subunit of NADPH oxidase, encoded by Nox2 (also known as Cybb) (Nox2-/- mice). In vitro studies were performed using human retinal endothelial cells (HRECs) treated with 15-HETE (0.1 μmol/l) or vehicle, with or without ER stress or NADPH oxidase inhibitors. This was followed by evaluation of ER stress response, NADPH oxidase expression/activity and the levels of phosphorylated vascular endothelial growth factor receptor-2 (p-VEGFR2) by western blotting and immunoprecipitation assays. Moreover, real-time imaging of intracellular calcium (Ca2+) release in HRECs treated with or without 15-HETE was performed using confocal microscopy. RESULTS Deletion of 12/15-Lo significantly attenuated diabetes-induced ER stress in mouse retina. In vitro, 15-HETE upregulated ER stress markers such as phosphorylated RNA-dependent protein kinase-like ER-regulated kinase (p-PERK), activating transcription factor 6 (ATF6) and protein disulfide isomerase (PDI) in HRECs. Inhibition of ER stress reduced 15-HETE-induced-leucocyte adhesion, VEGFR2 phosphorylation and NADPH oxidase expression/activity. However, inhibition of NADPH oxidase or deletion of Nox2 had no effect on ER stress induced by the 12/15-LO-derived metabolites both in vitro and in vivo. We also found that 15-HETE increases the intracellular calcium in HRECs. CONCLUSIONS/INTERPRETATION ER stress contributes to 12/15-LO-induced retinal inflammation in diabetic retinopathy via activation of NADPH oxidase and VEGFR2. Perturbation of calcium homeostasis in the retina might also play a role in linking 12/15-LO to retinal ER stress and subsequent microvascular dysfunction in diabetic retinopathy.
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Affiliation(s)
- Khaled Elmasry
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, 1460 Laney Walker Blvd., CB 2602, Augusta, GA, 30912, USA
- Department of Ophthalmology and Culver Vision Discovery Institute, Medical College of Georgia, Augusta University, Augusta, GA, USA
- Department of Oral Biology and Anatomy, Dental College of Georgia, Augusta University, Augusta, GA, USA
- Department of Human Anatomy and Embryology, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Ahmed S Ibrahim
- Department of Ophthalmology and Culver Vision Discovery Institute, Medical College of Georgia, Augusta University, Augusta, GA, USA
- Department of Oral Biology and Anatomy, Dental College of Georgia, Augusta University, Augusta, GA, USA
- Department of Biochemistry, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt
| | - Heba Saleh
- Department of Oral Biology and Anatomy, Dental College of Georgia, Augusta University, Augusta, GA, USA
| | - Nehal Elsherbiny
- Department of Biochemistry, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt
| | - Sally Elshafey
- Department of Oral Biology and Anatomy, Dental College of Georgia, Augusta University, Augusta, GA, USA
| | - Khaled A Hussein
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, 1460 Laney Walker Blvd., CB 2602, Augusta, GA, 30912, USA
- Oral Medicine and Surgery Research Division, National Research Centre, Dokki, Egypt
| | - Mohamed Al-Shabrawey
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, 1460 Laney Walker Blvd., CB 2602, Augusta, GA, 30912, USA.
- Department of Ophthalmology and Culver Vision Discovery Institute, Medical College of Georgia, Augusta University, Augusta, GA, USA.
- Department of Oral Biology and Anatomy, Dental College of Georgia, Augusta University, Augusta, GA, USA.
- Department of Human Anatomy and Embryology, Faculty of Medicine, Mansoura University, Mansoura, Egypt.
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25
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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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26
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Abstract
The ubiquitin-proteasome system (UPS) controls cellular functions by maintenance of a functional proteome and degradation of key regulatory proteins. Central to the UPS is the proteasome that adjusts the abundance of numerous proteins, thereby safeguarding their activity or initiating regulatory events. Here, we demonstrate that the essential Saccharomyces cerevisiae protein Yjr141w/Ipa1 (Important for cleavage and PolyAdenylation) belongs to the HECT_2 (homologous to E6-AP carboxyl terminus_2) family. We found that five cysteine residues within the HECT_2 family signature and the C-terminus are essential for Ipa1 activity. Furthermore, Ipa1 interacts with several ubiquitin-conjugating enzymes in vivo and localizes to the cytosol and nucleus. Importantly, Ipa1 has an impact on proteasome activity, which is indicated by the activation of the Rpn4 regulon as well as by decreased turnover of destabilized proteasome substrates in an IPA1 mutant. These changes in proteasome activity might be connected to reduced maturation or modification of proteasomal core particle proteins. Our results highlight the influence of Ipa1 on the UPS. The conservation within the HECT_2 family and the connection of the human HECT_2 family member to an age-related degeneration disease might suggest that HECT_2 family members share a conserved function linked to proteasome activity.
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Involvement of a gut-retina axis in protection against dietary glycemia-induced age-related macular degeneration. Proc Natl Acad Sci U S A 2017; 114:E4472-E4481. [PMID: 28507131 DOI: 10.1073/pnas.1702302114] [Citation(s) in RCA: 158] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Age-related macular degeneration (AMD) is the major cause of blindness in developed nations. AMD is characterized by retinal pigmented epithelial (RPE) cell dysfunction and loss of photoreceptor cells. Epidemiologic studies indicate important contributions of dietary patterns to the risk for AMD, but the mechanisms relating diet to disease remain unclear. Here we investigate the effect on AMD of isocaloric diets that differ only in the type of dietary carbohydrate in a wild-type aged-mouse model. The consumption of a high-glycemia (HG) diet resulted in many AMD features (AMDf), including RPE hypopigmentation and atrophy, lipofuscin accumulation, and photoreceptor degeneration, whereas consumption of the lower-glycemia (LG) diet did not. Critically, switching from the HG to the LG diet late in life arrested or reversed AMDf. LG diets limited the accumulation of advanced glycation end products, long-chain polyunsaturated lipids, and their peroxidation end-products and increased C3-carnitine in retina, plasma, or urine. Untargeted metabolomics revealed microbial cometabolites, particularly serotonin, as protective against AMDf. Gut microbiota were responsive to diet, and we identified microbiota in the Clostridiales order as being associated with AMDf and the HG diet, whereas protection from AMDf was associated with the Bacteroidales order and the LG diet. Network analysis revealed a nexus of metabolites and microbiota that appear to act within a gut-retina axis to protect against diet- and age-induced AMDf. The findings indicate a functional interaction between dietary carbohydrates, the metabolome, including microbial cometabolites, and AMDf. Our studies suggest a simple dietary intervention that may be useful in patients to arrest AMD.
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28
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Subnormothermic Perfusion in the Isolated Rat Liver Preserves the Antioxidant Glutathione and Enhances the Function of the Ubiquitin Proteasome System. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:9324692. [PMID: 27800122 PMCID: PMC5075307 DOI: 10.1155/2016/9324692] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 09/09/2016] [Accepted: 09/15/2016] [Indexed: 12/18/2022]
Abstract
The reduction of oxidative stress is suggested to be one of the main mechanisms to explain the benefits of subnormothermic perfusion against ischemic liver damage. In this study we investigated the early cellular mechanisms induced in isolated rat livers after 15 min perfusion at temperatures ranging from normothermia (37°C) to subnormothermia (26°C and 22°C). Subnormothermic perfusion was found to maintain hepatic viability. Perfusion at 22°C raised reduced glutathione levels and the activity of glutathione reductase; however, lipid and protein oxidation still occurred as determined by malondialdehyde, 4-hydroxynonenal-protein adducts, and advanced oxidation protein products. In livers perfused at 22°C the lysosomal and ubiquitin proteasome system (UPS) were both activated. The 26S chymotrypsin-like (β5) proteasome activity was significantly increased in the 26°C (46%) and 22°C (42%) groups. The increased proteasome activity may be due to increased Rpt6 Ser120 phosphorylation, which is known to enhance 26S proteasome activity. Together, our results indicate that the early events produced by subnormothermic perfusion in the liver can induce oxidative stress concomitantly with antioxidant glutathione preservation and enhanced function of the lysosomal and UPS systems. Thus, a brief hypothermia could trigger antioxidant mechanisms and may be functioning as a preconditioning stimulus.
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29
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Abstract
Aging is a progressive process determined by genetic and acquired factors. Among the latter are the chemical reactions referred to as nonenzymatic posttranslational modifications (NEPTMs), such as glycoxidation, which are responsible for protein molecular aging. Carbamylation is a more recently described NEPTM that is caused by the nonenzymatic binding of isocyanate derived from urea dissociation or myeloperoxidase-mediated catabolism of thiocyanate to free amino groups of proteins. This modification is considered an adverse reaction, because it induces alterations of protein and cell properties. It has been shown that carbamylated proteins increase in plasma and tissues during chronic kidney disease and are associated with deleterious clinical outcomes, but nothing is known to date about tissue protein carbamylation during aging. To address this issue, we evaluated homocitrulline rate, the most characteristic carbamylation-derived product (CDP), over time in skin of mammalian species with different life expectancies. Our results show that carbamylation occurs throughout the whole lifespan and leads to tissue accumulation of carbamylated proteins. Because of their remarkably long half-life, matrix proteins, like type I collagen and elastin, are preferential targets. Interestingly, the accumulation rate of CDPs is inversely correlated with longevity, suggesting the occurrence of still unidentified protective mechanisms. In addition, homocitrulline accumulates more intensely than carboxymethyl-lysine, one of the major advanced glycation end products, suggesting the prominent role of carbamylation over glycoxidation reactions in age-related tissue alterations. Thus, protein carbamylation may be considered a hallmark of aging in mammalian species that may significantly contribute in the structural and functional tissue damages encountered during aging.
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30
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Larabee CM, Georgescu C, Wren JD, Plafker SM. Expression profiling of the ubiquitin conjugating enzyme UbcM2 in murine brain reveals modest age-dependent decreases in specific neurons. BMC Neurosci 2015; 16:76. [PMID: 26566974 PMCID: PMC4644300 DOI: 10.1186/s12868-015-0194-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 08/24/2015] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND UbcM2 is a ubiquitin-conjugating enzyme with roles in the turnover of damaged and misfolded proteins, cell cycle progression, development, and regulation of the antioxidant transcription factor, Nrf2. Recent screens have identified binding partners of the enzyme that are associated with various neurodegenerative diseases, and our previous studies have shown that UbcM2 is enriched in retina and brain. RESULTS In the current study, we characterized UbcM2 protein expression in various structures and cell types in the murine brain. Immunofluorescence analysis of paraffin-embedded brain sections revealed that UbcM2 is ubiquitously expressed throughout the brain, is enriched in hindbrain and cortex, and is robustly expressed in neurons. In contrast, the enzyme is undetectable in most astrocytes and microglia. As dysfunction of the ubiquitin proteasome system (UPS) has been linked to many age-related neurological diseases, we compared UbcM2 expression levels in young versus aged wild-type mice and found a global decrease in expression in aged brains, with reductions of 10 % or greater in five substructures (cerebellar granule cell layer, primary motor cortex, olfactory nucleus, superior colliculus, and secondary visual cortex). CONCLUSIONS These studies represent the first protein expression profiling of a ubiquitin-conjugating enzyme in the brain and support the notion that deficits in protein degradation and proteostasis associated with neurodegenerative diseases may be, in part, attributable to age-dependent reductions in the enzymatic machinery of the UPS.
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Affiliation(s)
- Chelsea M Larabee
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, 825 Northeast 13th Street, Oklahoma City, OK, USA. .,Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
| | - Constantin Georgescu
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, 825 Northeast 13th Street, Oklahoma City, OK, USA.
| | - Jonathan D Wren
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, 825 Northeast 13th Street, Oklahoma City, OK, USA.
| | - Scott M Plafker
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, 825 Northeast 13th Street, Oklahoma City, OK, USA. .,Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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31
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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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Cuenca N, Fernández-Sánchez L, Campello L, Maneu V, De la Villa P, Lax P, Pinilla I. Cellular responses following retinal injuries and therapeutic approaches for neurodegenerative diseases. Prog Retin Eye Res 2014; 43:17-75. [PMID: 25038518 DOI: 10.1016/j.preteyeres.2014.07.001] [Citation(s) in RCA: 296] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 07/03/2014] [Accepted: 07/07/2014] [Indexed: 01/17/2023]
Abstract
Retinal neurodegenerative diseases like age-related macular degeneration, glaucoma, diabetic retinopathy and retinitis pigmentosa each have a different etiology and pathogenesis. However, at the cellular and molecular level, the response to retinal injury is similar in all of them, and results in morphological and functional impairment of retinal cells. This retinal degeneration may be triggered by gene defects, increased intraocular pressure, high levels of blood glucose, other types of stress or aging, but they all frequently induce a set of cell signals that lead to well-established and similar morphological and functional changes, including controlled cell death and retinal remodeling. Interestingly, an inflammatory response, oxidative stress and activation of apoptotic pathways are common features in all these diseases. Furthermore, it is important to note the relevant role of glial cells, including astrocytes, Müller cells and microglia, because their response to injury is decisive for maintaining the health of the retina or its degeneration. Several therapeutic approaches have been developed to preserve retinal function or restore eyesight in pathological conditions. In this context, neuroprotective compounds, gene therapy, cell transplantation or artificial devices should be applied at the appropriate stage of retinal degeneration to obtain successful results. This review provides an overview of the common and distinctive features of retinal neurodegenerative diseases, including the molecular, anatomical and functional changes caused by the cellular response to damage, in order to establish appropriate treatments for these pathologies.
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Affiliation(s)
- Nicolás Cuenca
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain; Multidisciplinary Institute for Environmental Studies "Ramon Margalef", University of Alicante, Alicante, Spain.
| | - Laura Fernández-Sánchez
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Laura Campello
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Victoria Maneu
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain
| | - Pedro De la Villa
- Department of Systems Biology, University of Alcalá, Alcalá de Henares, Spain
| | - Pedro Lax
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Isabel Pinilla
- Department of Ophthalmology, Lozano Blesa University Hospital, Aragon Institute of Health Sciences, Zaragoza, Spain
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Shang F, Wilmarth PA, Chang ML, Liu K, David LL, Caceres MA, Wawrousek E, Taylor A. Newborn mouse lens proteome and its alteration by lysine 6 mutant ubiquitin. J Proteome Res 2014; 13:1177-89. [PMID: 24450463 PMCID: PMC3993935 DOI: 10.1021/pr400801v] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
![]()
Ubiquitin is a tag that often initiates
degradation of proteins by
the proteasome in the ubiquitin proteasome system. Targeted expression
of K6W mutant ubiquitin (K6W-Ub) in the lens results in defects in
lens development and cataract formation, suggesting critical functions
for ubiquitin in lens. To study the developmental processes that require
intact ubiquitin, we executed the most extensive characterization
of the lens proteome to date. We quantified lens protein expression
changes in multiple replicate pools of P1 wild-type and K6W-Ub-expressing
mouse lenses. Lens proteins were digested with trypsin, peptides were
separated using strong cation exchange and reversed-phase liquid chromatography,
and tandem mass (MS/MS) spectra were collected with a linear ion trap.
Transgenic mice that expressed low levels of K6W-Ub (low expressers)
had normal, clear lenses at birth, whereas the lenses that expressed
high levels of K6W-Ub (higher expressers) had abnormal lenses and
cataracts at birth. A total of 2052 proteins were identified, of which
996 were reliably quantified and compared between wild-type and K6W-Ub
transgenic mice. Consistent with a delayed developmental program,
fiber-cell-specific proteins, such as γ-crystallins (γA,
γB, γC, and γE), were down-regulated in K6W-Ub higher
expressers. Up-regulated proteins were involved in energy metabolism,
signal transduction, and proteolysis. The K6W-Ub low expressers exhibited
delayed onset and milder cataract consistent with smaller changes
in protein expression. Because lens protein expression changes occurred
prior to lens morphological abnormalities and cataract formation in
K6W-Ub low expressers, it appears that expression of K6W-Ub sets in
motion a process of altered protein expression that results in developmental
defects and cataract.
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Affiliation(s)
- Fu Shang
- Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University , 711 Washington Steet, Boston, Massachusetts 02111, United States
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Impairment of the ubiquitin-proteasome pathway in RPE alters the expression of inflammation related genes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 801:237-50. [PMID: 24664704 DOI: 10.1007/978-1-4614-3209-8_31] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The ubiquitin-proteasome pathway (UPP) plays an important role in regulating gene expression. Retinal pigment epithelial cells (RPE) are a major source of ocular inflammatory cytokines. In this work we determined the relationship between impairment of the UPP and expression of inflammation-related factors. The UPP could be impaired by oxidative stress or chemical inhibition. Impairment of the UPP in RPE increased the expression of several inflammatory cytokines, such as IL-6 and IL-8. However, the expression of monocyte chemoattractant protein-1 (MCP-1) and complement factor H (CFH) and was reduced upon impairment of the UPP. These data suggest that impairment of the UPP in RPE may be one of the causes of retinal inflammation and abnormal functions of monocyte and the complement system during the pathogenesis of age-related macular degeneration.
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Whitcomb EA, Shang F, Taylor A. Common cell biologic and biochemical changes in aging and age-related diseases of the eye: toward new therapeutic approaches to age-related ocular diseases. Invest Ophthalmol Vis Sci 2013; 54:ORSF31-6. [PMID: 24335065 DOI: 10.1167/iovs.13-12808] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Elizabeth A Whitcomb
- Laboratory for Nutrition and Vision Research, USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
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Abstract
Lens opacification or cataract reduces vision in over 80 million people worldwide and blinds 18 million. These numbers will increase dramatically as both the size of the elderly demographic and the number of those with carbohydrate metabolism-related problems increase. Preventative measures for cataract are critical because the availability of cataract surgery in much of the world is insufficient. Epidemiologic literature suggests that the risk of cataract can be diminished by diets that are optimized for vitamin C, lutein/zeaxanthin, B vitamins, omega-3 fatty acids, multivitamins, and carbohydrates: recommended levels of micronutrients are salutary. The limited data from intervention trials provide some support for observational studies with regard to nuclear - but not other types of - cataracts. Presented here are the beneficial levels of nutrients in diets or blood and the total number of participants surveyed in epidemiologic studies since a previous review in 2007.
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Affiliation(s)
- Karen A Weikel
- Laboratory for Nutrition and Vision Research, JM-USDA Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts, USA
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Rodríguez‐Muela N, Koga H, García‐Ledo L, Villa P, Rosa EJ, Cuervo AM, Boya P. Balance between autophagic pathways preserves retinal homeostasis. Aging Cell 2013; 12:478-88. [PMID: 23521856 DOI: 10.1111/acel.12072] [Citation(s) in RCA: 139] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/09/2013] [Indexed: 01/20/2023] Open
Abstract
Aging contributes to the appearance of several retinopathies and is the largest risk factor for aged-related macular degeneration, major cause of blindness in the elderly population. Accumulation of undegraded material as lipofuscin represents a hallmark in many pathologies of the aged eye. Autophagy is a highly conserved intracellular degradative pathway that plays a critical role in the removal of damaged cell components to maintain the cellular homeostasis. A decrease in autophagic activity with age observed in many tissues has been proposed to contribute to the aggravation of age-related diseases. However, the participation of different autophagic pathways to the retina physiopathology remains unknown. Here, we describe a marked reduction in macroautophagic activity in the retina with age, which coincides with an increase in chaperone-mediated autophagy (CMA). This increase in CMA is also observed during retinal neurodegeneration in the Atg5(flox/flox) ; nestin-Cre mice, a mouse model with downregulation of macroautophagy in neuronal precursors. In contrast to other cell types, this autophagic cross talk in retinal cells is not bi-directional and CMA inhibition renders cone photoreceptor very sensitive to stress. Temporal and cell-type-specific differences in the balance between autophagic pathways may be responsible for the specific pattern of visual loss that occurs with aging. Our results show for the first time a cross talk of different lysosomal proteolytic systems in the retina during normal aging and may help the development of new therapeutic intervention for age-dependent retinal diseases.
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Affiliation(s)
- Natalia Rodríguez‐Muela
- Department of Cellular and Molecular Biology CIB CSIC Ramiro de Maeztu 9 E‐28040Madrid Spain
| | - Hiroshi Koga
- Department of Developmental and Molecular Biology and Institute for Aging Studies Albert Einstein College of Medicine Bronx NY 10461USA
| | - Lucía García‐Ledo
- Department of Cellular and Molecular Biology CIB CSIC Ramiro de Maeztu 9 E‐28040Madrid Spain
| | - Pedro Villa
- Department of Physiology Universidad de Alcalá E‐28871Alcalá de Henares Spain
| | - Enrique J. Rosa
- 3D Lab Department of Cellular and Molecular Medicine CIB CSIC Ramiro de Maeztu 9E‐28040Madrid Spain
| | - Ana María Cuervo
- Department of Developmental and Molecular Biology and Institute for Aging Studies Albert Einstein College of Medicine Bronx NY 10461USA
| | - Patricia Boya
- Department of Cellular and Molecular Biology CIB CSIC Ramiro de Maeztu 9 E‐28040Madrid Spain
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Klettner A, Kauppinen A, Blasiak J, Roider J, Salminen A, Kaarniranta K. Cellular and molecular mechanisms of age-related macular degeneration: from impaired autophagy to neovascularization. Int J Biochem Cell Biol 2013; 45:1457-67. [PMID: 23603148 DOI: 10.1016/j.biocel.2013.04.013] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Revised: 04/08/2013] [Accepted: 04/09/2013] [Indexed: 01/18/2023]
Abstract
Age-related macular degeneration (AMD) is a complex, degenerative and progressive disease involving multiple genetic and environmental factors. It can result in severe visual loss e.g. AMD is the leading cause of blindness in the elderly in the western countries. Although age, genetics, diet, smoking, and many cardiovascular factors are known to be linked with this disease there is increasing evidence that long-term oxidative stress, impaired autophagy clearance and inflammasome mediated inflammation are involved in the pathogenesis. Under certain conditions these may trigger detrimental processes e.g. release of vascular endothelial growth factor (VEGF), causing choroidal neovascularization e.g. in wet AMD. This review ties together these crucial pathological threads in AMD.
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Affiliation(s)
- Alexa Klettner
- Department of Ophthalmology, University Medical Center Schleswig-Holstein, Kiel, Germany
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Li DF, Feng L, Hou YJ, Liu W. The expression, purification and crystallization of a ubiquitin-conjugating enzyme E2 from Agrocybe aegerita underscore the impact of His-tag location on recombinant protein properties. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:153-7. [PMID: 23385757 PMCID: PMC3564618 DOI: 10.1107/s1744309112051755] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 12/23/2012] [Indexed: 01/12/2023]
Abstract
Ubiquitination is a post-translational modification involved in myriad cell regulation and disease pathways. The ubiquitin-conjugating (E2) enzyme is the central player in the ubiquitin-transfer pathway. Although a large array of E2 structures are available, not all E2 families have known structures and three-dimensional structures from fungal organisms other than yeast are lacking. Here, the expression, purification, crystallization and preliminary X-ray analysis of UbcA1, a novel ubiquitin-conjugating enzyme identified from the medicinal mushroom Agrocybe aegerita, which shows antitumour properties, are reported. As a potential anticancer drug candidate, the protein was expressed in either a C-terminally or an N-terminally His-tagged form. In the process of purification and crystallization, the location of the His tag seemed to play a crucial role in protein stability. In contrast to unsuccessful crystallization trials for the protein with a C-terminal tag, a crystal of N-terminally His-tagged UbcA1 grown under optimal conditions diffracted X-rays to 1.7 Å resolution. The crystal belonged to space group C2, with unit-cell parameters a = 84.93, b = 34.76, c = 128.10 Å, β = 118.57°. An X-ray data set was collected that was suitable for structure determination, showing satisfactory completeness, and R factors. All of these results underscore the non-negligible impact of His-tag location on protein behaviour during the process of purification and crystallization.
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Affiliation(s)
- De-Feng Li
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, People’s Republic of China
| | - Lei Feng
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, People’s Republic of China
| | - Yan-Jie Hou
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, People’s Republic of China
| | - Wei Liu
- Institute of Immunology, The Third Military Medical University, Chongqing 400038, People’s Republic of China
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Weikel KA, Chiu CJ, Taylor A. Nutritional modulation of age-related macular degeneration. Mol Aspects Med 2012; 33:318-75. [PMID: 22503690 DOI: 10.1016/j.mam.2012.03.005] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 03/30/2012] [Indexed: 11/24/2022]
Abstract
Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly worldwide. It affects 30-50 million individuals and clinical hallmarks of AMD are observed in at least one third of persons over the age of 75 in industrialized countries (Gehrs et al., 2006). Costs associated with AMD are in excess of $340 billion US (American-Health-Assistance-Foundation, 2012). The majority of AMD patients in the United States are not eligible for clinical treatments (Biarnes et al., 2011; Klein et al., 2011). Preventive interventions through dietary modulation are attractive strategies because many studies suggest a benefit of micro- and macronutrients with respect to AMD, as well as other age-related debilities, and with few, if any, adverse effects (Chiu, 2011). Preservation of vision would enhance quality of life for millions of elderly people, and alleviate the personal and public health financial burden of AMD (Frick et al., 2007; Wood et al., 2011). Observational studies indicate that maintaining adequate levels of omega-3 fatty acids (i.e. with 2 servings/week of fish) or a low glycemic index diet may be particularly beneficial for early AMD and that higher levels of carotenoids may be protective, most probably, against neovascular AMD. Intervention trials are needed to better understand the full effect of these nutrients and/or combinations of nutrients on retinal health. Analyses that describe effects of a nutrient on onset and/or progress of AMD are valuable because they indicate the value of a nutrient to arrest AMD at the early stages. This comprehensive summary provides essential information about the value of nutrients with regard to diminishing risk for onset or progress of AMD and can serve as a guide until data from ongoing intervention trials are available.
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Affiliation(s)
- Karen A Weikel
- Laboratory for Nutrition and Vision Research, JM-USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111, USA
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