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Rajeswaren V, Wong JO, Yabroudi D, Nahomi RB, Rankenberg J, Nam MH, Nagaraj RH. Small Heat Shock Proteins in Retinal Diseases. Front Mol Biosci 2022; 9:860375. [PMID: 35480891 PMCID: PMC9035800 DOI: 10.3389/fmolb.2022.860375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 03/11/2022] [Indexed: 11/29/2022] Open
Abstract
This review summarizes the latest findings on small heat shock proteins (sHsps) in three major retinal diseases: glaucoma, diabetic retinopathy, and age-related macular degeneration. A general description of the structure and major cellular functions of sHsps is provided in the introductory remarks. Their role in specific retinal diseases, highlighting their regulation, role in pathogenesis, and possible use as therapeutics, is discussed.
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Affiliation(s)
- Vivian Rajeswaren
- Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, School of Medicine, Aurora, CO, United States
| | - Jeffrey O. Wong
- Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, School of Medicine, Aurora, CO, United States
| | - Dana Yabroudi
- Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, School of Medicine, Aurora, CO, United States
| | - Rooban B. Nahomi
- Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, School of Medicine, Aurora, CO, United States
| | - Johanna Rankenberg
- Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, School of Medicine, Aurora, CO, United States
| | - Mi-Hyun Nam
- Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, School of Medicine, Aurora, CO, United States
- *Correspondence: Mi-Hyun Nam, ; Ram H. Nagaraj,
| | - Ram H. Nagaraj
- Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, School of Medicine, Aurora, CO, United States
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO, United States
- *Correspondence: Mi-Hyun Nam, ; Ram H. Nagaraj,
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Lulli M, Nencioni D, Papucci L, Schiavone N. Zeta-crystallin: a moonlighting player in cancer. Cell Mol Life Sci 2020; 77:965-976. [PMID: 31563996 PMCID: PMC11104887 DOI: 10.1007/s00018-019-03301-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 09/10/2019] [Accepted: 09/16/2019] [Indexed: 12/13/2022]
Abstract
Crystallins were firstly found as structural proteins of the eye lens. To this family belong proteins, such as ζ-crystallin, expressed ubiquitously, and endowed with enzyme activity. ζ-crystallin is a moonlighting protein endowed with two main different functions: (1) mRNA binding with stabilizing activity; (2) NADPH:quinone oxidoreductase. ζ-crystallin has been clearly demonstrated to stabilize mRNAs encoding proteins involved in renal glutamine catabolism during metabolic acidosis resulting in ammoniagenesis and bicarbonate ion production that concur to compensate such condition. ζ-crystallin binds also mRNAs encoding for antiapoptotic proteins, such as Bcl-2 in leukemia cells. On the other hand, the physiological role of its enzymatic activity is still elusive. Gathering research evidences and data mined from public databases, we provide a framework where all the known ζ-crystallin properties are called into question, making it a hypothetical pivotal player in cancer, allowing cells to hijack or subjugate the acidity response mechanism to increase their ability to resist oxidative stress and apoptosis, while fueling their glutamine addicted metabolism.
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Affiliation(s)
- Matteo Lulli
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Università Degli Studi di Firenze, Viale G.B. Morgagni, 50, Firenze, 50134, Italy.
| | - Daniele Nencioni
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Università Degli Studi di Firenze, Viale G.B. Morgagni, 50, Firenze, 50134, Italy
| | - Laura Papucci
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Università Degli Studi di Firenze, Viale G.B. Morgagni, 50, Firenze, 50134, Italy
| | - Nicola Schiavone
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Università Degli Studi di Firenze, Viale G.B. Morgagni, 50, Firenze, 50134, Italy.
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Zhu L, Titone R, Robertson DM. The impact of hyperglycemia on the corneal epithelium: Molecular mechanisms and insight. Ocul Surf 2019; 17:644-654. [PMID: 31238114 DOI: 10.1016/j.jtos.2019.06.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 06/11/2019] [Accepted: 06/21/2019] [Indexed: 12/15/2022]
Abstract
Type 2 Diabetes Mellitus (T2DM) is reaching epidemic levels worldwide and with it, there is a significant increase in complications associated with the disease. T2DM affects virtually all organ systems including the eye. While frequently overlooked, diabetic keratopathy is the most common ocular complication of diabetes and can manifest in mild to severe forms, the latter of which poses a major threat to vision. As the initial barrier between the environment and the eye, the corneal epithelium functions in innate immune defense. Compromise of this barrier may predispose the cornea to infection and can hinder the refractive capabilities of the eye. The clinical burden in patients with diabetic keratopathy lies primarily in the inability of the corneal epithelium to repair damage and maintain its tight barrier function. Current therapies for diabetic keratopathy are supportive, centering on the prevention of infection and promotion of an optimal healing environment. With no clear disease-modifying agent identified as of yet, a thorough understanding of the pathophysiology that underlies the development of diabetic keratopathy at the cellular level is critical to identify and develop potential therapeutic agents capable of promoting corneal re-epithelialization to accelerate the wound healing process. The focus of this review is to examine what is known regarding the cellular and molecular mechanisms needed to maintain epithelial homeostasis and how it goes awry in diabetes.
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Affiliation(s)
- Luke Zhu
- Department of Ophthalmology, University of Texas Southwestern Medical Center, United States
| | - Rossella Titone
- Department of Ophthalmology, University of Texas Southwestern Medical Center, United States
| | - Danielle M Robertson
- Department of Ophthalmology, University of Texas Southwestern Medical Center, United States.
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Pradeep SR, Srinivasan K. Ameliorative Influence of Dietary Fenugreek (Trigonella foenum-graecum) Seeds and Onion (Allium cepa) on Eye Lens Abnormalities via Modulation of Crystallin Proteins and Polyol Pathway in Experimental Diabetes. Curr Eye Res 2018; 43:1108-1118. [PMID: 29856678 DOI: 10.1080/02713683.2018.1484146] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
PURPOSE AND METHODS Hyperglycemia-induced osmotic and oxidative stress is thought to be involved in the pathogenesis of diabetes-related secondary complications including cataract. In continuation of our previous observation of the ameliorative influence of these spices on hyperglycemia, attendant metabolic abnormalities, and oxidative stress in tissues of diabetic rats, the beneficial influence of dietary (10%) fenugreek seeds, (3%) onion, or their combination was investigated on diabetes-induced alteration in the eye lens of streptozotocin-induced diabetic rats. RESULTS Animals maintained on these spices showed significantly countered oxidative stress markers (reactive oxygen species, lipid peroxidation and protein carbonyl), advanced glycation end products, and expression of their receptor in the eye lens. Increased activity of polyol pathway enzymes, their protein, and mRNA expression was significantly countered in the cataractogenic lens as a result of these dietary interventions. Altered crystallin (αA and αB) distribution profile, their expression, activity of carbohydrate metabolizing enzymes, and antioxidant status were significantly annulled by these dietary treatments. Physical and visual observation of the photomicrographs of the lenses of treated rats indicated that these dietary interventions delayed cataractogenesis in diabetic rats. CONCLUSIONS Overall, the present investigation evidenced a beneficial modulation of the progression of cataractogenesis by dietary fenugreek seeds and onion, implicating their potential in ameliorating cataract in diabetics.
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Affiliation(s)
- Seetur R Pradeep
- a Department of Biochemistry , CSIR-Central Food Technological Research Institute , Mysore , India
| | - Krishnapura Srinivasan
- a Department of Biochemistry , CSIR-Central Food Technological Research Institute , Mysore , India
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Anders F, Liu A, Mann C, Teister J, Lauzi J, Thanos S, Grus FH, Pfeiffer N, Prokosch V. The Small Heat Shock Protein α-Crystallin B Shows Neuroprotective Properties in a Glaucoma Animal Model. Int J Mol Sci 2017; 18:E2418. [PMID: 29135941 PMCID: PMC5713386 DOI: 10.3390/ijms18112418] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Revised: 11/10/2017] [Accepted: 11/12/2017] [Indexed: 11/29/2022] Open
Abstract
Glaucoma is a neurodegenerative disease that leads to irreversible retinal ganglion cell (RGC) loss and is one of the main causes of blindness worldwide. The pathogenesis of glaucoma remains unclear, and novel approaches for neuroprotective treatments are urgently needed. Previous studies have revealed significant down-regulation of α-crystallin B as an initial reaction to elevated intraocular pressure (IOP), followed by a clear but delayed up-regulation, suggesting that this small heat-shock protein plays a pathophysiological role in the disease. This study analyzed the neuroprotective effect of α-crystallin B in an experimental animal model of glaucoma. Significant IOP elevation induced by episcleral vein cauterization resulted in a considerable impairment of the RGCs and the retinal nerve fiber layer. An intravitreal injection of α-crystallin B at the time of the IOP increase was able to rescue the RGCs, as measured in a functional photopic electroretinogram, retinal nerve fiber layer thickness, and RGC counts. Mass-spectrometry-based proteomics and antibody-microarray measurements indicated that a α-crystallin injection distinctly up-regulated all of the subclasses (α, β, and γ) of the crystallin protein family. The creation of an interactive protein network revealed clear correlations between individual proteins, which showed a regulatory shift resulting from the crystallin injection. The neuroprotective properties of α-crystallin B further demonstrate the potential importance of crystallin proteins in developing therapeutic options for glaucoma.
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Affiliation(s)
- Fabian Anders
- Experimental Ophthalmology, Department of Ophthalmology, University Medical Center of the Johannes Gutenberg-University Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany.
| | - Aiwei Liu
- Experimental Ophthalmology, Department of Ophthalmology, University Medical Center of the Johannes Gutenberg-University Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany.
| | - Carolina Mann
- Experimental Ophthalmology, Department of Ophthalmology, University Medical Center of the Johannes Gutenberg-University Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany.
| | - Julia Teister
- Experimental Ophthalmology, Department of Ophthalmology, University Medical Center of the Johannes Gutenberg-University Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany.
| | - Jasmin Lauzi
- Experimental Ophthalmology, Department of Ophthalmology, University Medical Center of the Johannes Gutenberg-University Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany.
| | - Solon Thanos
- Department of Experimental Ophthalmology, School of Medicine, University of Münster, Albert-Schweitzer-Campus 1, 48149 Münster, Germany.
| | - Franz H Grus
- Experimental Ophthalmology, Department of Ophthalmology, University Medical Center of the Johannes Gutenberg-University Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany.
| | - Norbert Pfeiffer
- Experimental Ophthalmology, Department of Ophthalmology, University Medical Center of the Johannes Gutenberg-University Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany.
| | - Verena Prokosch
- Experimental Ophthalmology, Department of Ophthalmology, University Medical Center of the Johannes Gutenberg-University Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany.
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Sayed KM, Mahmoud AA. Heat shock protein-70 and hypoxia inducible factor-1α in type 2 diabetes mellitus patients complicated with retinopathy. Acta Ophthalmol 2016; 94:e361-6. [PMID: 26725915 DOI: 10.1111/aos.12919] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 09/27/2015] [Indexed: 01/04/2023]
Abstract
PURPOSE To elucidate the role of heat shock protein-70 (HSP70) and hypoxia inducible factor-1α (HIF-1α) in diabetic retinopathy (DR) patients. DESIGN AND METHODS A comparative study was done on the serum level of both HSP70 and HIF-1α in 50 patients with type 2 diabetes mellitus (T2DM) without DR, 50 patients with T2DM and DR and 70 healthy control subjects. RESULTS HSP70 and HIF-1α were significantly increased in T2DM patients compared to controls and increased in patients with T2DM & DR compared to T2DM patients without DR (p < 0.0001). HSP70 did not differ among the patients with different stages of DR, while HIF-1α increased significantly in grades 3 and 4 DR patients compared to grades 1 and 2 DR patients. A strong correlation was found between HIF-1α and the development of DR (r = 0.835, p = 0.00) but not with HSP70. HIF-1α can be used as a predictor for development of DR but not HSP70. CONCLUSIONS Our study was the first that investigated both HSP70 and HIF-1α in humans and was the first that measured their levels in serum of patients with DR. The study suggested that HSP70 might have a protective function in T2DM patients rather than a therapeutic function. HIF-1α had an upper hand in the development and progression of DR. Induction of HSP70 and blockage of HIF-1α could lead to the development of novel prophylactic and therapeutic strategies for DR and potentially other diabetic complications.
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Affiliation(s)
- Khulood M. Sayed
- The Department of Ophthalmology; Faculty of Medicine; Sohag University; Sohag Egypt
| | - Aida A. Mahmoud
- The Department of Biochemistry; Faculty of Medicine; Sohag University; Sohag Egypt
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Anbarasu K, Sivakumar J. Multidimensional significance of crystallin protein-protein interactions and their implications in various human diseases. Biochim Biophys Acta Gen Subj 2015; 1860:222-33. [PMID: 26365509 DOI: 10.1016/j.bbagen.2015.09.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 08/28/2015] [Accepted: 09/08/2015] [Indexed: 02/07/2023]
Abstract
BACKGROUND Crystallins are the important structural and functional proteins in the eye lens responsible for refractive index. Post-translational modifications (PTMs) and mutations are major causative factors that affect crystallin structural conformation and functional characteristics thus playing a vital role in the etiology of cataractogenesis. SCOPE OF REVIEW The significance of crystallin protein-protein interactions (PPIs) in the lens and non-lenticular tissues is summarized. MAJOR CONCLUSIONS Aberrancy of PPIs between crystallin, its associated protein and metal ions has been accomplished in various human diseases including cataract. A detailed account on multidimensional structural and functional significance of crystallin PPI in humans must be brought into limelight, in order to understand the biochemical and molecular basis augmenting the aberrancies of such interaction. In this scenario, the present review is focused to shed light on studies which will aid to expand our present understanding on disease pathogenesis related to loss of PPI thereby paving the way for putative future therapeutic targets to curb such diseases. GENERAL SIGNIFICANCE The interactions with α-crystallins always aid to protect their structural and functional characteristics. The up-regulation of αB-crystallin in the non-lenticular tissues always decodes as biomarker for various stress related disorders. For better understanding and treatment of various diseases, PPI studies provide overall outline about the structural and functional characteristics of the proteins. This information not only helps to find out the route of cataractogenesis but also aid to identify potential molecules to inhibit/prevent the further development of such complicated phenomenon. This article is part of a Special Issue entitled Crystallin Biochemistry in Health and Disease.
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Affiliation(s)
- Kumarasamy Anbarasu
- Department of Marine Biotechnology, Bharathidasan University, Tiruchirapalli 620024, Tamil Nadu, India.
| | - Jeyarajan Sivakumar
- Department of Marine Biotechnology, Bharathidasan University, Tiruchirapalli 620024, Tamil Nadu, India
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Torok Z, Peto T, Csosz E, Tukacs E, Molnar AM, Berta A, Tozser J, Hajdu A, Nagy V, Domokos B, Csutak A. Combined Methods for Diabetic Retinopathy Screening, Using Retina Photographs and Tear Fluid Proteomics Biomarkers. J Diabetes Res 2015; 2015:623619. [PMID: 26221613 PMCID: PMC4499636 DOI: 10.1155/2015/623619] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Background. It is estimated that 347 million people suffer from diabetes mellitus (DM), and almost 5 million are blind due to diabetic retinopathy (DR). The progression of DR can be slowed down with early diagnosis and treatment. Therefore our aim was to develop a novel automated method for DR screening. Methods. 52 patients with diabetes mellitus were enrolled into the project. Of all patients, 39 had signs of DR. Digital retina images and tear fluid samples were taken from each eye. The results from the tear fluid proteomics analysis and from digital microaneurysm (MA) detection on fundus images were used as the input of a machine learning system. Results. MA detection method alone resulted in 0.84 sensitivity and 0.81 specificity. Using the proteomics data for analysis 0.87 sensitivity and 0.68 specificity values were achieved. The combined data analysis integrated the features of the proteomics data along with the number of detected MAs in the associated image and achieved sensitivity/specificity values of 0.93/0.78. Conclusions. As the two different types of data represent independent and complementary information on the outcome, the combined model resulted in a reliable screening method that is comparable to the requirements of DR screening programs applied in clinical routine.
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Affiliation(s)
- Zsolt Torok
- Department of Computer Graphics and Image Processing, Bioinformatics Research Group, Faculty of Informatics, University of Debrecen, Egyetem tér 1, Debrecen 4032, Hungary
- Department of Ophthalmology, Faculty of Medicine, University of Debrecen, Egyetem tér 1, Debrecen 4032, Hungary
- Astridbio Technologies Inc., 439 University Avenue, Toronto, ON, Canada M5G 1Y8
- *Zsolt Torok:
| | - Tunde Peto
- NIHR Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, 162 City Road, London EC1V 2PD, UK
| | - Eva Csosz
- Department of Biochemistry and Molecular Biology, Proteomics Core Facility, Faculty of Medicine, University of Debrecen, Egyetem tér 1, Debrecen 4032, Hungary
| | - Edit Tukacs
- Department of Computer Graphics and Image Processing, Bioinformatics Research Group, Faculty of Informatics, University of Debrecen, Egyetem tér 1, Debrecen 4032, Hungary
- Astridbio Technologies Inc., 439 University Avenue, Toronto, ON, Canada M5G 1Y8
| | - Agnes M. Molnar
- Centre for Research on Inner City Health, Keenan Research Centre, Li Ka Shing Knowledge Institute, St Michael's Hospital, 30 Bond Street, Toronto, ON, Canada M5B 1W8
| | - Andras Berta
- Department of Ophthalmology, Faculty of Medicine, University of Debrecen, Egyetem tér 1, Debrecen 4032, Hungary
- InnoTears Ltd., Szent Anna Utca 37/1. 2. em. 1, Debrecen 4024, Hungary
| | - Jozsef Tozser
- Department of Biochemistry and Molecular Biology, Proteomics Core Facility, Faculty of Medicine, University of Debrecen, Egyetem tér 1, Debrecen 4032, Hungary
- InnoTears Ltd., Szent Anna Utca 37/1. 2. em. 1, Debrecen 4024, Hungary
| | - Andras Hajdu
- Department of Computer Graphics and Image Processing, Bioinformatics Research Group, Faculty of Informatics, University of Debrecen, Egyetem tér 1, Debrecen 4032, Hungary
| | - Valeria Nagy
- Department of Ophthalmology, Faculty of Medicine, University of Debrecen, Egyetem tér 1, Debrecen 4032, Hungary
| | - Balint Domokos
- Astridbio Technologies Inc., 439 University Avenue, Toronto, ON, Canada M5G 1Y8
| | - Adrienne Csutak
- Department of Ophthalmology, Faculty of Medicine, University of Debrecen, Egyetem tér 1, Debrecen 4032, Hungary
- InnoTears Ltd., Szent Anna Utca 37/1. 2. em. 1, Debrecen 4024, Hungary
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Marozas LM, Fort PE. Diabetic Retinopathy-Update on Prevention Techniques, Present Therapies, and New Leads. ACTA ACUST UNITED AC 2014; 7:54-58. [PMID: 25419235 DOI: 10.17925/usor.2014.07.01.54] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Diabetic retinopathy is the major ocular complication associated with diabetes, and represents the leading cause of legal blindness in the working-age population of developed countries. Although classically diagnosed based on abnormalities of the retinal microvasculature, diabetic retinopathy is now widely recognized as a neurovascular disease. While all patients with diabetes are at increased risk for eye disease including diabetic retinopathy, proactive measures, and timely intervention can prevent or delay subsequent vision loss. Systemic management of diabetes by combined control of glycemia, blood pressure, and serum lipid levels remains the most important method of preventing diabetic retinopathy onset and progression. Once detected, surgical and medical interventions including photocoagulation, vitrectomy, and intravitral drug injection can help preserve vision. However, the need for improved detection methods and therapies that will allow earlier diagnosis and treatment remains apparent. This review summarizes current techniques for the prevention and intervention for diabetic retinopathy, and examines ongoing developments in the search for new endpoints and therapies as they apply to preventing vision loss associated with diabetes.
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Affiliation(s)
- Lauren M Marozas
- Undergraduate Student, Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, US
| | - Patrice E Fort
- Assistant Professor, Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, US
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Nahomi RB, Palmer A, Green KM, Fort PE, Nagaraj RH. Pro-inflammatory cytokines downregulate Hsp27 and cause apoptosis of human retinal capillary endothelial cells. Biochim Biophys Acta Mol Basis Dis 2013; 1842:164-74. [PMID: 24252613 DOI: 10.1016/j.bbadis.2013.11.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 10/25/2013] [Accepted: 11/12/2013] [Indexed: 01/10/2023]
Abstract
The formation of acellular capillaries in the retina, a hallmark feature of diabetic retinopathy, is caused by apoptosis of endothelial cells and pericytes. The biochemical mechanism of such apoptosis remains unclear. Small heat shock proteins play an important role in the regulation of apoptosis. In the diabetic retina, pro-inflammatory cytokines are upregulated. In this study, we investigated the effects of pro-inflammatory cytokines on small heat shock protein 27 (Hsp27) in human retinal endothelial cells (HREC). In HREC cultured in the presence of cytokine mixtures (CM), a significant downregulation of Hsp27 at the protein and mRNA level occurred, with no effect on HSF-1, the transcription factor for Hsp27. The presence of high glucose (25mM) amplified the effects of cytokines on Hsp27. CM activated indoleamine 2,3-dioxygenase (IDO) and enhanced the production of kynurenine and ROS. An inhibitor of IDO, 1-methyl tryptophan (MT), inhibited the effects of CM on Hsp27. CM also upregulated NOS2 and, consequently, nitric oxide (NO). A NOS inhibitor, L-NAME, and a ROS scavenger blocked the CM-mediated Hsp27 downregulation. While a NO donor in the culture medium did not decrease the Hsp27 content, a peroxynitrite donor and exogenous peroxynitrite did. The cytokines and high glucose-induced apoptosis of HREC were inhibited by MT and L-NAME. Downregulation of Hsp27 by a siRNA treatment promoted apoptosis in HREC. Together, these data suggest that pro-inflammatory cytokines induce the formation of ROS and NO, which, through the formation of peroxynitrite, reduce the Hsp27 content and bring about apoptosis of retinal capillary endothelial cells.
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Affiliation(s)
- Rooban B Nahomi
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Allison Palmer
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Katelyn M Green
- Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA
| | - Patrice E Fort
- Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA
| | - Ram H Nagaraj
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
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Torok Z, Peto T, Csosz E, Tukacs E, Molnar A, Maros-Szabo Z, Berta A, Tozser J, Hajdu A, Nagy V, Domokos B, Csutak A. Tear fluid proteomics multimarkers for diabetic retinopathy screening. BMC Ophthalmol 2013; 13:40. [PMID: 23919537 PMCID: PMC3770351 DOI: 10.1186/1471-2415-13-40] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 07/31/2013] [Indexed: 12/17/2022] Open
Abstract
Background The aim of the project was to develop a novel method for diabetic retinopathy screening based on the examination of tear fluid biomarker changes. In order to evaluate the usability of protein biomarkers for pre-screening purposes several different approaches were used, including machine learning algorithms. Methods All persons involved in the study had diabetes. Diabetic retinopathy (DR) was diagnosed by capturing 7-field fundus images, evaluated by two independent ophthalmologists. 165 eyes were examined (from 119 patients), 55 were diagnosed healthy and 110 images showed signs of DR. Tear samples were taken from all eyes and state-of-the-art nano-HPLC coupled ESI-MS/MS mass spectrometry protein identification was performed on all samples. Applicability of protein biomarkers was evaluated by six different optimally parameterized machine learning algorithms: Support Vector Machine, Recursive Partitioning, Random Forest, Naive Bayes, Logistic Regression, K-Nearest Neighbor. Results Out of the six investigated machine learning algorithms the result of Recursive Partitioning proved to be the most accurate. The performance of the system realizing the above algorithm reached 74% sensitivity and 48% specificity. Conclusions Protein biomarkers selected and classified with machine learning algorithms alone are at present not recommended for screening purposes because of low specificity and sensitivity values. This tool can be potentially used to improve the results of image processing methods as a complementary tool in automatic or semiautomatic systems.
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Affiliation(s)
- Zsolt Torok
- Department of Computer Graphics and Image Processing, University of Debrecen, Faculty of Informatics, Debrecen, Hungary.
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