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Xiao K, Li L, Chen Y, Lin R, Wen B, Wang Z, Huang Y. Diagnostic application in streptozotocin-induced diabetic retinopathy rats: A study based on Raman spectroscopy and machine learning. JOURNAL OF BIOPHOTONICS 2024; 17:e202400115. [PMID: 39155125 DOI: 10.1002/jbio.202400115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 04/23/2024] [Accepted: 04/30/2024] [Indexed: 08/20/2024]
Abstract
Vision impairment caused by diabetic retinopathy (DR) is often irreversible, making early-stage diagnosis imperative. Raman spectroscopy emerges as a powerful tool, capable of providing molecular fingerprints of tissues. This study employs RS to detect ex vivo retinal tissue from diabetic rats at various stages of the disease. Transmission electron microscopy was utilized to reveal the ultrastructural changes in retinal tissue. Following spectral preprocessing of the acquired data, the random forest and orthogonal partial least squares-discriminant analysis algorithms were employed for spectral data analysis. The entirety of Raman spectra and all annotated bands accurately and distinctly differentiate all animal groups, and can identify significant molecules from the spectral data. Bands at 524, 1335, 543, and 435 cm-1 were found to be associated with the preproliferative phase of DR. Bands at 1045 and 1335 cm-1 were found to be associated with early stages of DR.
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Affiliation(s)
- Kunhong Xiao
- Department of Ophthalmology and Optometry, Fujian Medical University, Fuzhou, Fujian Province, China
| | - Li Li
- Department of Ophthalmology and Optometry, Fujian Medical University, Fuzhou, Fujian Province, China
- Department of Ophthalmology, Fujian Provincial Hospital, Fuzhou, Fujian Province, China
| | - Yang Chen
- Department of Laboratory Medicine, Key Laboratory of Clinical Laboratory Technology for Precision Medicine (Fujian Medical University), Fujian Province University, Fujian Medical University, Fuzhou, Fujian Province, China
| | - Rong Lin
- Department of Ophthalmology and Optometry, Fujian Medical University, Fuzhou, Fujian Province, China
| | - Boyuan Wen
- Department of Ophthalmology and Optometry, Fujian Medical University, Fuzhou, Fujian Province, China
| | - Zhiqiang Wang
- Department of Ophthalmology, Daping Hospital, Army Medical University, Chongqing, China
| | - Yan Huang
- Department of Ophthalmology and Optometry, Fujian Medical University, Fuzhou, Fujian Province, China
- Department of Ophthalmology, Fujian Provincial Hospital, Fuzhou, Fujian Province, China
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2
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Mandla R, Lorenz K, Yin X, Bocher O, Huerta-Chagoya A, Arruda AL, Piron A, Horn S, Suzuki K, Hatzikotoulas K, Southam L, Taylor H, Yang K, Hrovatin K, Tong Y, Lytrivi M, Rayner NW, Meigs JB, McCarthy MI, Mahajan A, Udler MS, Spracklen CN, Boehnke M, Vujkovic M, Rotter JI, Eizirik DL, Cnop M, Lickert H, Morris AP, Zeggini E, Voight BF, Mercader JM. Multi-omics characterization of type 2 diabetes associated genetic variation. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.07.15.24310282. [PMID: 39072045 PMCID: PMC11275663 DOI: 10.1101/2024.07.15.24310282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
Discerning the mechanisms driving type 2 diabetes (T2D) pathophysiology from genome-wide association studies (GWAS) remains a challenge. To this end, we integrated omics information from 16 multi-tissue and multi-ancestry expression, protein, and metabolite quantitative trait loci (QTL) studies and 46 multi-ancestry GWAS for T2D-related traits with the largest, most ancestrally diverse T2D GWAS to date. Of the 1,289 T2D GWAS index variants, 716 (56%) demonstrated strong evidence of colocalization with a molecular or T2D-related trait, implicating 657 cis-effector genes, 1,691 distal-effector genes, 731 metabolites, and 43 T2D-related traits. We identified 773 of these cis- and distal-effector genes using either expression QTL data from understudied ancestry groups or inclusion of T2D index variants enriched in underrepresented populations, emphasizing the value of increasing population diversity in functional mapping. Linking these variants, genes, metabolites, and traits into a network, we elucidated mechanisms through which T2D-associated variation may impact disease risk. Finally, we showed that drugs targeting effector proteins were enriched in those approved to treat T2D, highlighting the potential of these results to prioritize drug targets for T2D. These results represent a leap in the molecular characterization of T2D-associated genetic variation and will aid in translating genetic findings into novel therapeutic strategies.
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Affiliation(s)
- Ravi Mandla
- Programs in Metabolism and Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Diabetes Unit, Endocrine Division, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Kim Lorenz
- Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Institute for Translational Medicine and Therapeutics, University of Pennsylvania - Perelman School of Medicine, Philadelphia PA
| | - Xianyong Yin
- Department of Epidemiology, School of Public Health, Nanjing Medical University, Nanjing, China
- Department of Biostatistics and Center for Statistical Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Ozvan Bocher
- Institute of Translational Genomics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Alicia Huerta-Chagoya
- Programs in Metabolism and Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Ana Luiza Arruda
- Institute of Translational Genomics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- Graduate School of Experimental Medicine, Technical University of Munich, Munich, Germany
| | - Anthony Piron
- ULB Center for Diabetes Research, Medical Faculty, Université Libre de Bruxelles, Brussels, Belgium
- Interuniversity Institute of Bioinformatics in Brussels (IB2), Brussels, Belgium
- Machine Learning Group, Université Libre de Bruxelles, Brussels, Belgium
- Diabetes and Inflammation Laboratory, Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Susanne Horn
- Institute of Translational Genomics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Ken Suzuki
- Centre for Genetics and Genomics Versus Arthritis, Centre for Musculoskeletal Research, Division of Musculoskeletal and Dermatological Sciences, University of Manchester, Manchester, UK
- Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
- Department of Statistical Genetics, Osaka University Graduate School of Medicine, Suita, Japan
| | - Konstantinos Hatzikotoulas
- Institute of Translational Genomics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Lorraine Southam
- Institute of Translational Genomics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Henry Taylor
- Center for Precision Health Research, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
- British Heart Foundation Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
- Heart and Lung Research Institute, University of Cambridge, Cambridge, UK
| | - Kaiyuan Yang
- Institute of Diabetes and Regeneration Research (IDR), Helmholtz Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Karin Hrovatin
- Institute of Computational Biology (ICB), Helmholtz Munich, Neuherberg, Germany
- School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Yue Tong
- ULB Center for Diabetes Research, Medical Faculty, Université Libre de Bruxelles, Brussels, Belgium
| | - Maria Lytrivi
- ULB Center for Diabetes Research, Medical Faculty, Université Libre de Bruxelles, Brussels, Belgium
- Division of Endocrinology, Erasmus Hospital, Universite Libre de Bruxelles, Brussels, Belgium
| | - Nigel W. Rayner
- Institute of Translational Genomics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - James B. Meigs
- Programs in Metabolism and Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
- Division of General Internal Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Mark I. McCarthy
- Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
- Oxford NIHR Biomedical Research Centre, Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Anubha Mahajan
- Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Miriam S. Udler
- Programs in Metabolism and Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Diabetes Unit, Endocrine Division, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Cassandra N. Spracklen
- Department of Biostatistics and Epidemiology, University of Massachusetts Amherst, Amherst, MA, USA
| | - Michael Boehnke
- Department of Biostatistics and Center for Statistical Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Marijana Vujkovic
- Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
- Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Jerome I. Rotter
- Institute for Translational Genomics and Population Sciences, Department of Pediatrics, Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Decio L. Eizirik
- ULB Center for Diabetes Research, Medical Faculty, Université Libre de Bruxelles, Brussels, Belgium
| | - Miriam Cnop
- ULB Center for Diabetes Research, Medical Faculty, Université Libre de Bruxelles, Brussels, Belgium
- Division of Endocrinology, Erasmus Hospital, Universite Libre de Bruxelles, Brussels, Belgium
- WEL Research Institute, Wavre, Belgium
| | - Heiko Lickert
- Institute of Diabetes and Regeneration Research (IDR), Helmholtz Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- School of Medicine, Technical University of Munich, Munich, Germany
| | - Andrew P. Morris
- Institute of Translational Genomics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- Centre for Genetics and Genomics Versus Arthritis, Centre for Musculoskeletal Research, Division of Musculoskeletal and Dermatological Sciences, University of Manchester, Manchester, UK
- Estonian Genome Centre, Institute of Genomics, University of Tartu, Tartu, Estonia
| | - Eleftheria Zeggini
- Institute of Translational Genomics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- TUM School of Medicine and Health, Technical University of Munich and Klinikum Rechts der Isar, Munich, Germany
| | - Benjamin F. Voight
- Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Institute for Translational Medicine and Therapeutics, University of Pennsylvania - Perelman School of Medicine, Philadelphia PA
| | - Josep M. Mercader
- Programs in Metabolism and Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Diabetes Unit, Endocrine Division, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
- Division of General Internal Medicine, Massachusetts General Hospital, Boston, MA, USA
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3
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Dorweiler TF, Singh A, Ganju A, Lydic TA, Glazer LC, Kolesnick RN, Busik JV. Diabetic retinopathy is a ceramidopathy reversible by anti-ceramide immunotherapy. Cell Metab 2024; 36:1521-1533.e5. [PMID: 38718792 PMCID: PMC11222062 DOI: 10.1016/j.cmet.2024.04.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 03/08/2024] [Accepted: 04/17/2024] [Indexed: 05/16/2024]
Abstract
Diabetic retinopathy is a microvascular disease that causes blindness. Using acid sphingomyelinase knockout mice, we reported that ceramide generation is critical for diabetic retinopathy development. Here, in patients with proliferative diabetic retinopathy, we identify vitreous ceramide imbalance with pathologic long-chain C16-ceramides increasing and protective very long-chain C26-ceramides decreasing. C16-ceramides generate pro-inflammatory/pro-apoptotic ceramide-rich platforms on endothelial surfaces. To geo-localize ceramide-rich platforms, we invented a three-dimensional confocal assay and showed that retinopathy-producing cytokines TNFα and IL-1β induce ceramide-rich platform formation on retinal endothelial cells within seconds, with volumes increasing 2-logs, yielding apoptotic death. Anti-ceramide antibodies abolish these events. Furthermore, intravitreal and systemic anti-ceramide antibodies protect from diabetic retinopathy in standardized rodent ischemia reperfusion and streptozotocin models. These data support (1) retinal endothelial ceramide as a diabetic retinopathy treatment target, (2) early-stage therapy of non-proliferative diabetic retinopathy to prevent progression, and (3) systemic diabetic retinopathy treatment; and they characterize diabetic retinopathy as a "ceramidopathy" reversible by anti-ceramide immunotherapy.
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Affiliation(s)
- Tim F Dorweiler
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA; Vascular Biology Program, Boston Children's Hospital and Department of Surgery, Harvard Medical School, Boston, MA 02113, USA
| | - Arjun Singh
- Memorial Sloan Kettering Cancer Center, Molecular Pharmacology Program, Sloan Kettering Institute New York, New York, NY 10065, USA
| | - Aditya Ganju
- Memorial Sloan Kettering Cancer Center, Molecular Pharmacology Program, Sloan Kettering Institute New York, New York, NY 10065, USA
| | - Todd A Lydic
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | - Louis C Glazer
- Vitreo-Retinal Associates, Grand Rapids, MI 49546, USA; Ophthalmology, Michigan State University, East Lansing, MI 48824, USA
| | - Richard N Kolesnick
- Memorial Sloan Kettering Cancer Center, Molecular Pharmacology Program, Sloan Kettering Institute New York, New York, NY 10065, USA.
| | - Julia V Busik
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA; Biochemistry and Physiology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
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4
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Wilkerson JL, Tatum SM, Holland WL, Summers SA. Ceramides are fuel gauges on the drive to cardiometabolic disease. Physiol Rev 2024; 104:1061-1119. [PMID: 38300524 PMCID: PMC11381030 DOI: 10.1152/physrev.00008.2023] [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: 02/14/2023] [Revised: 01/23/2024] [Accepted: 01/25/2024] [Indexed: 02/02/2024] Open
Abstract
Ceramides are signals of fatty acid excess that accumulate when a cell's energetic needs have been met and its nutrient storage has reached capacity. As these sphingolipids accrue, they alter the metabolism and survival of cells throughout the body including in the heart, liver, blood vessels, skeletal muscle, brain, and kidney. These ceramide actions elicit the tissue dysfunction that underlies cardiometabolic diseases such as diabetes, coronary artery disease, metabolic-associated steatohepatitis, and heart failure. Here, we review the biosynthesis and degradation pathways that maintain ceramide levels in normal physiology and discuss how the loss of ceramide homeostasis drives cardiometabolic pathologies. We highlight signaling nodes that sense small changes in ceramides and in turn reprogram cellular metabolism and stimulate apoptosis. Finally, we evaluate the emerging therapeutic utility of these unique lipids as biomarkers that forecast disease risk and as targets of ceramide-lowering interventions that ameliorate disease.
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Affiliation(s)
- Joseph L Wilkerson
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, United States
| | - Sean M Tatum
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, United States
| | - William L Holland
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, United States
| | - Scott A Summers
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, United States
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5
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Guo J, Chen S, Zhang Y, Liu J, Jiang L, Hu L, Yao K, Yu Y, Chen X. Cholesterol metabolism: physiological regulation and diseases. MedComm (Beijing) 2024; 5:e476. [PMID: 38405060 PMCID: PMC10893558 DOI: 10.1002/mco2.476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 01/09/2024] [Accepted: 01/12/2024] [Indexed: 02/27/2024] Open
Abstract
Cholesterol homeostasis is crucial for cellular and systemic function. The disorder of cholesterol metabolism not only accelerates the onset of cardiovascular disease (CVD) but is also the fundamental cause of other ailments. The regulation of cholesterol metabolism in the human is an extremely complex process. Due to the dynamic balance between cholesterol synthesis, intake, efflux and storage, cholesterol metabolism generally remains secure. Disruption of any of these links is likely to have adverse effects on the body. At present, increasing evidence suggests that abnormal cholesterol metabolism is closely related to various systemic diseases. However, the exact mechanism by which cholesterol metabolism contributes to disease pathogenesis remains unclear, and there are still unknown factors. In this review, we outline the metabolic process of cholesterol in the human body, especially reverse cholesterol transport (RCT). Then, we discuss separately the impact of abnormal cholesterol metabolism on common diseases and potential therapeutic targets for each disease, including CVD, tumors, neurological diseases, and immune system diseases. At the end of this review, we focus on the effect of cholesterol metabolism on eye diseases. In short, we hope to provide more new ideas for the pathogenesis and treatment of diseases from the perspective of cholesterol.
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Affiliation(s)
- Jiarui Guo
- Eye Center of the Second Affiliated HospitalZhejiang University School of MedicineHangzhouZhejiang ProvinceChina
| | - Silong Chen
- Eye Center of the Second Affiliated HospitalZhejiang University School of MedicineHangzhouZhejiang ProvinceChina
| | - Ying Zhang
- Eye Center of the Second Affiliated HospitalZhejiang University School of MedicineHangzhouZhejiang ProvinceChina
- Institute of Translational MedicineZhejiang University School of MedicineHangzhouZhejiang ProvinceChina
| | - Jinxia Liu
- Eye Center of the Second Affiliated HospitalZhejiang University School of MedicineHangzhouZhejiang ProvinceChina
| | - Luyang Jiang
- Eye Center of the Second Affiliated HospitalZhejiang University School of MedicineHangzhouZhejiang ProvinceChina
| | - Lidan Hu
- National Clinical Research Center for Child HealthThe Children's HospitalZhejiang University School of MedicineHangzhouZhejiang ProvinceChina
| | - Ke Yao
- Eye Center of the Second Affiliated HospitalZhejiang University School of MedicineHangzhouZhejiang ProvinceChina
| | - Yibo Yu
- Eye Center of the Second Affiliated HospitalZhejiang University School of MedicineHangzhouZhejiang ProvinceChina
| | - Xiangjun Chen
- Eye Center of the Second Affiliated HospitalZhejiang University School of MedicineHangzhouZhejiang ProvinceChina
- Institute of Translational MedicineZhejiang University School of MedicineHangzhouZhejiang ProvinceChina
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6
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Fernandes Silva L, Hokkanen J, Vangipurapu J, Oravilahti A, Laakso M. Metabolites as Risk Factors for Diabetic Retinopathy in Patients With Type 2 Diabetes: A 12-Year Follow-up Study. J Clin Endocrinol Metab 2023; 109:100-106. [PMID: 37560996 PMCID: PMC10735554 DOI: 10.1210/clinem/dgad452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 06/29/2023] [Accepted: 08/09/2023] [Indexed: 08/11/2023]
Abstract
CONTEXT Diabetic retinopathy (DR) is a specific microvascular complication in patients with diabetes and the leading cause of blindness. Recent advances in omics, especially metabolomics, offer the possibility identifying novel potential biomarkers for DR. OBJECTIVE The aim was to identify metabolites associated with DR. METHODS We performed a 12-year follow-up study including 1349 participants with type 2 diabetes (1021 without DR, 328 with DR) selected from the METSIM cohort. Individuals who had retinopathy before the baseline study were excluded (n = 63). The diagnosis of retinopathy was based on fundus photography examination. We performed nontargeted metabolomics profiling to identify metabolites. RESULTS We found 17 metabolites significantly associated with incident DR after adjustment for confounding factors. Among amino acids, N-lactoyl isoleucine, N-lactoyl valine, N-lactoyl tyrosine, N-lactoyl phenylalanine, N-(2-furoyl) glycine, and 5-hydroxylysine were associated with an increased risk of DR, and citrulline with a decreased risk of DR. Among the fatty acids N,N,N-trimethyl-5-aminovalerate was associated with an increased risk of DR, and myristoleate (14:1n5), palmitoleate (16:1n7), and 5-dodecenoate (12:1n7) with a decreased risk of DR. Sphingomyelin (d18:2/24:2), a sphingolipid, was significantly associated with a decreased risk of DR. Carboxylic acid maleate and organic compounds 3-hydroxypyridine sulfate, 4-vinylphenol sulfate, 4-ethylcatechol sulfate, and dimethyl sulfone were significantly associated with an increased risk of DR. CONCLUSION Our study is the first large population-based longitudinal study to identify metabolites for DR. We found multiple metabolites associated with an increased and decreased risk for DR from several different metabolic pathways.
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Affiliation(s)
- Lilian Fernandes Silva
- Institute of Clinical Medicine, Internal Medicine, University of Eastern Finland, 70211 Kuopio, Finland
| | - Jenna Hokkanen
- Institute of Clinical Medicine, Internal Medicine, University of Eastern Finland, 70211 Kuopio, Finland
| | - Jagadish Vangipurapu
- Institute of Clinical Medicine, Internal Medicine, University of Eastern Finland, 70211 Kuopio, Finland
| | - Anniina Oravilahti
- Institute of Clinical Medicine, Internal Medicine, University of Eastern Finland, 70211 Kuopio, Finland
| | - Markku Laakso
- Institute of Clinical Medicine, Internal Medicine, University of Eastern Finland, 70211 Kuopio, Finland
- Department of Internal Medicine, Kuopio University Hospital, 70211 Kuopio, Finland
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7
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Ye S, Wang Z, Ma JH, Ji S, Peng Y, Huang Y, Chen J, Tang S. Diabetes Reshapes the Circadian Transcriptome Profile in Murine Retina. Invest Ophthalmol Vis Sci 2023; 64:3. [PMID: 37788001 PMCID: PMC10552875 DOI: 10.1167/iovs.64.13.3] [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: 07/04/2023] [Accepted: 09/09/2023] [Indexed: 10/04/2023] Open
Abstract
Purpose Diabetic retinopathy (DR) is a common complication of diabetes and has a high prevalence. Dysregulation of circadian rhythmicity is associated with the development of DR. This research aimed to investigate rhythmical transcriptome alterations in the retina of diabetic mice. Methods C57BL/6J mice were used to establish a diabetes model by intraperitoneal injection of streptozotocin (STZ). After 12 weeks, retinas were collected continuously at 4-hour intervals over 1 day. Total RNA was extracted from normal and STZ-treated retinas and RNA sequencing was performed. Meta2d algorithm, Kyoto Encyclopedia of Genes, Phase Set Enrichment Analysis, and time-series cluster analysis were used to identify, analyze and annotate the composition, phase, and molecular functions of rhythmic transcripts in retinas. Results The retina exhibited powerful transcriptome rhythmicity. STZ-induced diabetes markedly modified the transcriptome characteristics of the circadian transcriptome in the retina, including composition, phase, and amplitude. Moreover, the diabetic mice led to re-organized temporal and clustering enrichment pathways in space and time and affected core clock machinery. Conclusions Diabetes impairs the circadian rhythm of the transcriptomic profile of retinas. This study offers new perspectives on the negative effects of diabetes on the retina, which may provide important information for the development of new treatments for DR.
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Affiliation(s)
- Suna Ye
- AIER Eye Hospital, Jinan University, Guangzhou, China
- AIER Eye Institute, Changsha, China
| | | | | | | | | | | | - Jiansu Chen
- AIER Eye Hospital, Jinan University, Guangzhou, China
- AIER Eye Institute, Changsha, China
| | - Shibo Tang
- AIER Eye Hospital, Jinan University, Guangzhou, China
- AIER Eye Institute, Changsha, China
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8
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Pistritu DV, Vasiliniuc AC, Vasiliu A, Visinescu EF, Visoiu IE, Vizdei S, Martínez Anghel P, Tanca A, Bucur O, Liehn EA. Phospholipids, the Masters in the Shadows during Healing after Acute Myocardial Infarction. Int J Mol Sci 2023; 24:ijms24098360. [PMID: 37176067 PMCID: PMC10178977 DOI: 10.3390/ijms24098360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/02/2023] [Accepted: 05/03/2023] [Indexed: 05/15/2023] Open
Abstract
Phospholipids are major components of cell membranes with complex structures, high heterogeneity and critical biological functions and have been used since ancient times to treat cardiovascular disease. Their importance and role were shadowed by the difficulty or incomplete available research methodology to study their biological presence and functionality. This review focuses on the current knowledge about the roles of phospholipids in the pathophysiology and therapy of cardiovascular diseases, which have been increasingly recognized. Used in singular formulation or in inclusive combinations with current drugs, phospholipids proved their positive and valuable effects not only in the protection of myocardial tissue, inflammation and fibrosis but also in angiogenesis, coagulation or cardiac regeneration more frequently in animal models as well as in human pathology. Thus, while mainly neglected by the scientific community, phospholipids present negligible side effects and could represent an ideal target for future therapeutic strategies in healing myocardial infarction. Acknowledging and understanding their mechanisms of action could offer a new perspective into novel therapeutic strategies for patients suffering an acute myocardial infarction, reducing the burden and improving the general social and economic outcome.
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Affiliation(s)
- Dan-Valentin Pistritu
- Victor Babes' National Institute of Pathology, 99-101 Splaiul Independentei, 050096 Bucharest, Romania
| | | | - Anda Vasiliu
- Victor Babes' National Institute of Pathology, 99-101 Splaiul Independentei, 050096 Bucharest, Romania
| | - Elena-Florentina Visinescu
- Faculty of Human Medicine, Carol Davila University of Medicine and Pharmacy, 37 Dionisie Lupu Street, 020021 Bucharest, Romania
| | - Ioana-Elena Visoiu
- Faculty of Human Medicine, Carol Davila University of Medicine and Pharmacy, 37 Dionisie Lupu Street, 020021 Bucharest, Romania
| | - Smaranda Vizdei
- Faculty of Human Medicine, Carol Davila University of Medicine and Pharmacy, 37 Dionisie Lupu Street, 020021 Bucharest, Romania
| | - Paula Martínez Anghel
- Victor Babes' National Institute of Pathology, 99-101 Splaiul Independentei, 050096 Bucharest, Romania
- Business Academy Aarhus, 30 Sønderhøj, 8260 Viby J, Denmark
| | - Antoanela Tanca
- Victor Babes' National Institute of Pathology, 99-101 Splaiul Independentei, 050096 Bucharest, Romania
- Faculty of Human Medicine, Carol Davila University of Medicine and Pharmacy, 37 Dionisie Lupu Street, 020021 Bucharest, Romania
| | - Octavian Bucur
- Victor Babes' National Institute of Pathology, 99-101 Splaiul Independentei, 050096 Bucharest, Romania
- Viron Molecular Medicine Institute, 201 Washington Street, Boston, MA 02108, USA
| | - Elisa Anamaria Liehn
- Victor Babes' National Institute of Pathology, 99-101 Splaiul Independentei, 050096 Bucharest, Romania
- Institute for Molecular Medicine, University of Southern Denmark, 25 J.B Winsløws Vej, 5230 Odense, Denmark
- National Heart Center Singapore, 5 Hospital Dr., Singapore 169609, Singapore
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9
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Shen Y, Wang H, Fang J, Liu K, Xu X. Novel insights into the mechanisms of hard exudate in diabetic retinopathy: Findings of serum lipidomic and metabolomics profiling. Heliyon 2023; 9:e15123. [PMID: 37089301 PMCID: PMC10119565 DOI: 10.1016/j.heliyon.2023.e15123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 03/25/2023] [Accepted: 03/27/2023] [Indexed: 04/03/2023] Open
Abstract
Objective Retinal hard exudates (HEs) result from lipoproteins leaking from capillaries into extracellular retinal space, and are related to decreased visual acuity in diabetic retinopathy (DR). This study aims to identify differential serum lipids and metabolites associated with HEs. Materials and methods A cross-sectional study was conducted Jul 2017 ∼ Mar 2021. We assessed the amount of HEs using standard ETDRS photographs for comparison. HEs severity was rated as "no or questionable", "moderate" or "severe". Serum samples were processed via high coverage pseudotargeted lipidomics analysis, and untargeted liquid chromatography coupled with time-of-flight mass spectrometry for metabolomics study, respectively. Weighted gene co-expression network analyses, partial least squares-discriminant analysis, and multi-receiver operating characteristic analysis were applied. Results A total of 167 patients were included. Discovery group: 116 eyes (116 patients). Validation group: 51 eyes (51 patients). 888 lipids were detected and divided into 18 modules (MEs), ME1 ∼ ME18. Lipids in ME1 significantly increased in patients with HEs in DR (NPDR and PDR combined), NPDR, and PDR, respectively. ME1 enriched to triglycerides (29%), ceramides (17%), and N-acylethanolamines (15%). A combined model of 20 lipids was the best to discriminate HEs, area under curve = 0.804, 95% confidence interval = 0.674-0.916. For metabolomics analysis, 19 metabolites and 13 pathways associated with HEs were identified. Taurine and hypotaurine metabolism, cysteine and methionine metabolism were closely related to HEs (P < 0.01). Conclusions The lipids and metabolites identified may serve as prediction biomarkers in the early stage of HEs in DR.
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10
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Agbaga MP, McClellan ME, Elliott MH. Analysis of Lipids, Fatty Acid, and Cholesterol in Membrane Microdomains. Methods Mol Biol 2023; 2625:129-139. [PMID: 36653639 PMCID: PMC11238714 DOI: 10.1007/978-1-0716-2966-6_12] [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] [Indexed: 01/19/2023]
Abstract
The original concept that lipid and protein components are randomly distributed in cellular membranes has been challenged by evidence of compartmentalization of such components into discrete membrane microdomains (known as lipid rafts). The lipid microdomain hypothesis has generated significant controversy and rigorous inquiry to test the idea that such domains concentrate machinery to mediate cellular processes such as signaling, synaptic plasticity, and endocytosis. As such, a large number of studies have used biochemical, cell biological, and biophysical methodologies to define the composition of membrane microdomains in experimental contexts. Although biochemical preparation strategies are not without limitations (as discussed herein), the isolation of detergent-resistant and detergent-free membrane domains can provide important information about the segregation of lipids and proteins in membranes. In this chapter, we describe methodologies to isolate membranes from cell or tissue sources with biophysical/biochemical properties of membrane microdomains and also provide methods for subsequent classical or mass spectrometry-based lipid analytical approaches.
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Affiliation(s)
- Martin-Paul Agbaga
- Department of Ophthalmology/Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Mark E McClellan
- Department of Ophthalmology/Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Michael H Elliott
- Department of Ophthalmology/Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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11
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Fan J, Liu J, Liu J, Angel PM, Drake RR, Wu Y, Fan H, Koutalos Y, Crosson CE. Sphingomyelinases in retinas and optic nerve heads: Effects of ocular hypertension and ischemia. Exp Eye Res 2022; 224:109250. [PMID: 36122624 PMCID: PMC10694736 DOI: 10.1016/j.exer.2022.109250] [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: 02/03/2022] [Revised: 08/12/2022] [Accepted: 09/12/2022] [Indexed: 11/28/2022]
Abstract
Sphingomyelinases (SMase), enzymes that catalyze the hydrolysis of sphingomyelin to ceramide, are important sensors for inflammatory cytokines and apoptotic signaling. Studies have provided evidence that increased SMase activity can contribute to retinal injury. In most tissues, two major SMases are responsible for stress-induced increases in ceramide: acid sphingomyelinase (ASMase) and Mg2+-dependent neutral sphingomyelinase (NSMase). The purposes of the current study were to determine the localization of SMases and their substrates in the retina and optic nerve head and to investigate the effects of ocular hypertension and ischemia on ASMase and NSMase activities. Tissue and cellular localization of ASMase and NSMase were determined by immunofluorescence imaging. Tissue localization of sphingomyelin in retinas was further determined by Matrix-Assisted Laser Desorption/Ionization mass spectrometry imaging. Tissue levels of sphingomyelins and ceramide were determined by liquid chromatography with tandem mass spectrometry. Sphingomyelinase activities under basal conditions and following acute ischemic and ocular hypotensive stress were measured using the Amplex Red Sphingomyelinase Assay Kit. Our data show that ASMase is in the optic nerve head and the retinal ganglion cell layer. NSMase is in the optic nerve head, photoreceptor and retinal ganglion cell layers. Both ASMase and NSMase were identified in human induced pluripotent stem cell-derived retinal ganglion cells and optic nerve head astrocytes. The retina and optic nerve head each exhibited unique distribution of sphingomyelins with the abundance of very long chain species being higher in the optic nerve head than in the retina. Basal activities for ASMase in retinas and optic nerve heads were 54.98 ± 2.5 and 95.6 ± 19.5 mU/mg protein, respectively. Ocular ischemia significantly increased ASMase activity to 86.2 ± 15.3 mU/mg protein in retinas (P = 0.03) but not in optic nerve heads (81.1 ± 15.3 mU/mg protein). Ocular hypertension significantly increased ASMase activity to 121.6 ± 7.3 mU/mg protein in retinas (P < 0.001) and 267.0 ± 66.3 mU/mg protein in optic nerve heads (P = 0.03). Basal activities for NSMase in retinas and optic nerve heads were 12.3 ± 2.1 and 37.9 ± 8.7 mU/mg protein, respectively. No significant change in NSMase activity was measured following ocular ischemia or hypertension. Our results provide evidence that both ASMase and NSMase are expressed in retinas and optic nerve heads; however, basal ASMase activity is significantly higher than NSMase activity in retinas and optic nerve heads. In addition, only ASMase activity was significantly increased in ocular ischemia or hypertension. These data support a role for ASMase-mediated sphingolipid metabolism in the development of retinal ischemic and hypertensive injuries.
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Affiliation(s)
- Jie Fan
- Storm Eye Institute, Medical University of South Carolina, Department of Ophthalmology, Charleston, SC, USA.
| | - Jian Liu
- Storm Eye Institute, Medical University of South Carolina, Department of Ophthalmology, Charleston, SC, USA
| | - Jiali Liu
- Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Department of Ophthalmology, 274 Middle Zhijiang Road, Jingan District, Shanghai, 200071, China
| | - Peggi M Angel
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics and MUSC Proteomics Center, Medical University of South Carolina, Charleston, SC, USA
| | - Richard R Drake
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics and MUSC Proteomics Center, Medical University of South Carolina, Charleston, SC, USA
| | - Yan Wu
- Department of Pathology & Laboratory Medicine, Medical University of South Carolina, Charleston, SC, USA
| | - Hongkuan Fan
- Department of Pathology & Laboratory Medicine, Medical University of South Carolina, Charleston, SC, USA
| | - Yiannis Koutalos
- Storm Eye Institute, Medical University of South Carolina, Department of Ophthalmology, Charleston, SC, USA
| | - Craig E Crosson
- Storm Eye Institute, Medical University of South Carolina, Department of Ophthalmology, Charleston, SC, USA
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12
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Liu H, Stepicheva NA, Ghosh S, Shang P, Chowdhury O, Daley RA, Yazdankhah M, Gupta U, Hose SL, Valapala M, Fitting CS, Strizhakova A, Shan Y, Feenstra D, Sahel JA, Jayagopal A, Handa JT, Zigler JS, Fort PE, Sodhi A, Sinha D. Reducing Akt2 in retinal pigment epithelial cells causes a compensatory increase in Akt1 and attenuates diabetic retinopathy. Nat Commun 2022; 13:6045. [PMID: 36229454 PMCID: PMC9561713 DOI: 10.1038/s41467-022-33773-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 10/03/2022] [Indexed: 01/14/2023] Open
Abstract
The retinal pigment epithelium (RPE) plays an important role in the development of diabetic retinopathy (DR), a leading cause of blindness worldwide. Here we set out to explore the role of Akt2 signaling-integral to both RPE homeostasis and glucose metabolism-to DR. Using human tissue and genetically manipulated mice (including RPE-specific conditional knockout (cKO) and knock-in (KI) mice), we investigate whether Akts in the RPE influences DR in models of diabetic eye disease. We found that Akt1 and Akt2 activities were reciprocally regulated in the RPE of DR donor tissue and diabetic mice. Akt2 cKO attenuated diabetes-induced retinal abnormalities through a compensatory upregulation of phospho-Akt1 leading to an inhibition of vascular injury, inflammatory cytokine release, and infiltration of immune cells mediated by the GSK3β/NF-κB signaling pathway; overexpression of Akt2 has no effect. We propose that targeting Akt1 activity in the RPE may be a novel therapy for treating DR.
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Affiliation(s)
- Haitao Liu
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Nadezda A. Stepicheva
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Sayan Ghosh
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Peng Shang
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA ,grid.280881.b0000 0001 0097 5623Present Address: Doheny Eye Institute, Pasadena, CA USA
| | - Olivia Chowdhury
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Rachel A. Daley
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Meysam Yazdankhah
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA ,grid.443945.b0000 0004 0566 7998Present Address: Neural Stem Cell Institute, Rensselaer, NY USA
| | - Urvi Gupta
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Stacey L. Hose
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Mallika Valapala
- grid.411377.70000 0001 0790 959XSchool of Optometry, Indiana University, Bloomington, IN USA
| | - Christopher Scott Fitting
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Anastasia Strizhakova
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Yang Shan
- grid.214458.e0000000086837370Kellogg Eye Center, University of Michigan School of Medicine, Ann Arbor, MI USA
| | - Derrick Feenstra
- grid.417570.00000 0004 0374 1269Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Ltd., Basel, Switzerland
| | - José-Alain Sahel
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA ,grid.462844.80000 0001 2308 1657Institut de la Vision, INSERM, CNRS, Sorbonne Université, Paris, France
| | | | - James T. Handa
- grid.21107.350000 0001 2171 9311The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - J. Samuel Zigler
- grid.21107.350000 0001 2171 9311The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Patrice E. Fort
- grid.214458.e0000000086837370Kellogg Eye Center, University of Michigan School of Medicine, Ann Arbor, MI USA
| | - Akrit Sodhi
- grid.21107.350000 0001 2171 9311The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Debasish Sinha
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. .,The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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13
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Whole-Exome Sequencing Revealed New Candidate Genes for Human Dilated Cardiomyopathy. Diagnostics (Basel) 2022; 12:diagnostics12102411. [PMID: 36292100 PMCID: PMC9600457 DOI: 10.3390/diagnostics12102411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 09/29/2022] [Accepted: 10/02/2022] [Indexed: 11/17/2022] Open
Abstract
Dilated cardiomyopathy (DCM) is a complex disease affecting young adults. It is a pathological condition impairing myocardium activity that leads to heart failure and, in the most severe cases, transplantation, which is currently the only possible therapy for the disease. DCM can be attributed to many genetic determinants interacting with environmental factors, resulting in a highly variable phenotype. Due to this complexity, the early identification of causative gene mutations is an important goal to provide a genetic diagnosis, implement pre-symptomatic interventions, and predict prognosis. The advent of next-generation sequencing (NGS) has opened a new path for mutation screening, and exome sequencing provides a promising approach for identifying causal variants in known genes and novel disease-associated candidates. We analyzed the whole-exome sequencing (WES) of 15 patients affected by DCM without overloading (hypertension, valvular, or congenital heart disease) or chronic ischemic conditions. We identified 70 pathogenic or likely pathogenic variants and 1240 variants of uncertain clinical significance. Gene ontology enrichment analysis was performed to assess the potential connections between affected genes and biological or molecular function, identifying genes directly related to extracellular matrix organization, transcellular movement through the solute carrier and ATP-binding cassette transporter, and vitamin B12 metabolism. We found variants in genes implicated to a different extent in cardiac function that may represent new players in the complex genetic scenario of DCM.
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14
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A Comprehensive Profiling of Cellular Sphingolipids in Mammalian Endothelial and Microglial Cells Cultured in Normal and High-Glucose Conditions. Cells 2022; 11:cells11193082. [PMID: 36231042 PMCID: PMC9563724 DOI: 10.3390/cells11193082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 09/20/2022] [Accepted: 09/23/2022] [Indexed: 11/17/2022] Open
Abstract
Sphingolipids (SPLs) play a diverse role in maintaining cellular homeostasis. Dysregulated SPL metabolism is associated with pathological changes in stressed and diseased cells. This study investigates differences in SPL metabolism between cultured human primary retinal endothelial (HREC) and murine microglial cells (BV2) in normal conditions (normal glucose, NG, 5 mM) and under high-glucose (HG, 25 mM)-induced stress by sphingolipidomics, immunohistochemistry, biochemical, and molecular assays. Measurable differences were observed in SPL profiles between HREC and BV2 cells. High-glucose treatment caused a >2.5-fold increase in the levels of Lactosyl-ceramide (LacCer) in HREC, but in BV2 cells, it induced Hexosyl-Ceramides (HexCer) by threefold and a significant increase in Sphingosine-1-phosphate (S1P) compared to NG. Altered SPL profiles coincided with changes in transcript levels of inflammatory and vascular permeability mediators in HREC and inflammatory mediators in BV2 cells. Differences in SPL profiles and differential responses to HG stress between endothelial and microglial cells suggest that SPL metabolism and signaling differ in mammalian cell types and, therefore, their pathological association with those cell types.
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15
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Aldosari DI, Malik A, Alhomida AS, Ola MS. Implications of Diabetes-Induced Altered Metabolites on Retinal Neurodegeneration. Front Neurosci 2022; 16:938029. [PMID: 35911994 PMCID: PMC9328693 DOI: 10.3389/fnins.2022.938029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 06/09/2022] [Indexed: 11/13/2022] Open
Abstract
Diabetic retinopathy (DR) is one of the major complications of diabetic eye diseases, causing vision loss and blindness worldwide. The concept of diabetic retinopathy has evolved from microvascular disease into more complex neurovascular disorders. Early in the disease progression of diabetes, the neuronal and glial cells are compromised before any microvascular abnormalities clinically detected by the ophthalmoscopic examination. This implies understanding the pathophysiological mechanisms at the early stage of disease progression especially due to diabetes-induced metabolic alterations to damage the neural retina so that early intervention and treatments options can be identified to prevent and inhibit the progression of DR. Hyperglycemia has been widely considered the major contributor to the progression of the retinal damage, even though tight control of glucose does not seem to have a bigger effect on the incidence or progression of retinal damage that leads to DR. Emerging evidence suggests that besides diabetes-induced hyperglycemia, dyslipidemia and amino acid defects might be a major contributor to the progression of early neurovascular retinal damage. In this review, we have discussed recent advances in the alterations of key metabolites of carbohydrate, lipid, and amino acids and their implications for neurovascular damage in DR.
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16
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Chen Y, Li G, Bhat OM, Li X, Zhang Y, Li PL. Impairment of Ceramide-Mediated Endothelial Instant Membrane Resealing During Diabetes Mellitus. Front Physiol 2022; 13:910339. [PMID: 35874544 PMCID: PMC9298829 DOI: 10.3389/fphys.2022.910339] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 06/14/2022] [Indexed: 01/01/2023] Open
Abstract
Recent studies have indicated that instant cell membrane resealing (ICMR) controls the activation of NOD-like receptor pyrin domain containing 3 (Nlrp3) inflammasomes in endothelial cells, thereby initiating and promoting vascular inflammation. It remains unknown whether this impaired ICMR occurs under diabetic condition or hyperglycemia contributing to endothelial dysfunction leading to vascular inflammation, a hallmark of diabetic vascular injury. The present study aims to examine whether ICMR occurs during in control and diabetic mice and to explore related molecular mechanisms associated with acid sphingomyelinase (ASM)-mediated ceramide production. Using confocal microscopy, we demonstrated that mouse aortic endothelial cells (MAECs) exposed to high glucose levels exhibited much more retarded ICMR after laser-induced membrane injury, compared to that in control cells. The high glucose-induced impairment of membrane resealing in MAECs was prevented when these cells were pretreated with sphingomyelin or C24-ceramide. Mechanistically, high glucose treatment decreased association of membrane ceramide with annexin A5, an essential element of membrane repair machinery. Consistently, the association of ceramide with annexin A5 was significantly reduced in the coronary arterial endothelium of mice with streptozotocin-induced diabetes mellitus compared to that in non-diabetic control mice. Moreover, a marked reduction of the association of ceramide with annexin A5 was observed in coronary arterial endothelium of ASM knockout mice regardless of their diabetic status. Lastly, high glucose treatment or ASM gene deletion substantially impaired ICMR in coronary arterial endothelium of mice receiving membrane puncturing agents. Collectively, our data suggest that ceramide-mediated ICMR in vascular endothelial cells is impaired during diabetes mellitus due to dissociation of ceramide with annexin A5 and ASM play a critical role in this ICMR.
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Affiliation(s)
- Yang Chen
- School of Chinese Materia Medica, Guangzhou University of Chinese Medicine, Guangzhou, China
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
| | - Guangbi Li
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
| | - Owais M. Bhat
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
| | - Xiang Li
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX, United States
| | - Yang Zhang
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX, United States
| | - Pin-Lan Li
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
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17
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Investigation of DHA-Induced Regulation of Redox Homeostasis in Retinal Pigment Epithelium Cells through the Combination of Metabolic Imaging and Molecular Biology. Antioxidants (Basel) 2022; 11:antiox11061072. [PMID: 35739970 PMCID: PMC9219962 DOI: 10.3390/antiox11061072] [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: 05/06/2022] [Revised: 05/23/2022] [Accepted: 05/26/2022] [Indexed: 12/13/2022] Open
Abstract
Diabetes-induced oxidative stress leads to the onset of vascular complications, which are major causes of disability and death in diabetic patients. Among these, diabetic retinopathy (DR) often arises from functional alterations of the blood-retinal barrier (BRB) due to damaging oxidative stress reactions in lipids, proteins, and DNA. This study aimed to investigate the impact of the ω3-polyunsaturated docosahexaenoic acid (DHA) on the regulation of redox homeostasis in the human retinal pigment epithelial (RPE) cell line (ARPE-19) under hyperglycemic-like conditions. The present results show that the treatment with DHA under high-glucose conditions activated erythroid 2-related factor Nrf2, which orchestrates the activation of cellular antioxidant pathways and ultimately inhibits apoptosis. This process was accompanied by a marked increase in the expression of NADH (Nicotinamide Adenine Dinucleotide plus Hydrogen) Quinone Oxidoreductase 1 (Nqo1), which is correlated with a contextual modulation and intracellular re-organization of the NAD+/NADH redox balance. This investigation of the mechanisms underlying the impairment induced by high levels of glucose on redox homeostasis of the BRB and the subsequent recovery provided by DHA provides both a powerful indicator for the detection of RPE cell impairment as well as a potential metabolic therapeutic target for the early intervention in its treatment.
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18
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Alsbirk KE, Seland JH, Assmus J. Diabetic retinopathy and visual impairment in a Norwegian diabetic coast population with a high dietary intake of fish oils. An observational study. Acta Ophthalmol 2022; 100:e532-e538. [PMID: 34472215 DOI: 10.1111/aos.14977] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 06/19/2021] [Accepted: 07/01/2021] [Indexed: 12/14/2022]
Abstract
PURPOSE To present retinal and visual findings in a Norwegian west coast diabetic population and to elucidate the effect of dietary intake of marine polyunsaturated fatty acids (PUFAs) on the development of diabetic retinopathy (DR). METHODS In an eye practice in an archipelago of 314 km², serving a population of about 40 000, we recorded the prevalence of visual impairment and DR in a referred diabetic population. 510 consecutive patients were included, 238 females and 272 males. 50 patients had type I and 460 had type II diabetes mellitus (DM). Self-reported medication, diet supplements, HbA1c and fish consumption were registered. RESULTS In the type I group, the median age was 44.5 and median DM duration 11.5 years [1-44]. 48% had photographic evidence of DR, 8 patients (16%) had proliferative retinopathy (PDR), and 6 patients (12%) had diabetic macular oedema (DME). All had best-corrected visual acuity (BCVA) of 0.5 (log MAR 0.3) or better in the best eye. In the type II group, the median DM duration was 8 years [1-53], and median age was 66. 98% had best eye BCVA at or better than 0.5 (log MAR 0.3) in the best eye. CONCLUSION None of the 510 patients had BCVA worse than 0.3 (log MAR 0.48) due to diabetic retinopathy. Compared to similar studies, we found a very low visual impairment rate. A possible protective effect of PUFA on the prevalence and progression of diabetic microangiopathy including retinopathy is discussed.
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Affiliation(s)
| | | | - Jörg Assmus
- Centre for Clinical Research Haukeland University Hospital Bergen Norway
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19
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Rajagopal R, Sylvester B, Zhang S, Adak S, Wei X, Bowers M, Jessberger S, Hsu FF, Semenkovich CF. Glucose-mediated de novo lipogenesis in photoreceptors drives early diabetic retinopathy. J Biol Chem 2021; 297:101104. [PMID: 34425110 PMCID: PMC8445899 DOI: 10.1016/j.jbc.2021.101104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 08/10/2021] [Accepted: 08/18/2021] [Indexed: 11/23/2022] Open
Abstract
Diabetic retinopathy (DR) is an increasingly frequent cause of blindness across populations; however, the events that initiate pathophysiology of DR remain elusive. Strong preclinical and clinical evidence suggests that abnormalities in retinal lipid metabolism caused by diabetes may account for the origin of this disease. A major arm of lipid metabolism, de novo biosynthesis, is driven by elevation in available glucose, a common thread binding all forms of vision loss in diabetes. Therefore, we hypothesized that aberrant retinal lipid biogenesis is an important promoter of early DR. In murine models, we observed elevations of diabetes-associated retinal de novo lipogenesis ∼70% over control levels. This shift was primarily because of activation of fatty acid synthase (FAS), a rate-limiting enzyme in the biogenic pathway. Activation of FAS was driven by canonical glucose-mediated disinhibition of acetyl-CoA carboxylase, a major upstream regulatory enzyme. Mutant mice expressing gain-of-function FAS demonstrated increased vulnerability to DR, whereas those with FAS deletion in rod photoreceptors maintained preserved visual responses upon induction of diabetes. Excess retinal de novo lipogenesis—either because of diabetes or because of FAS gain of function—was associated with modestly increased levels of palmitate-containing phosphatidylcholine species in synaptic membranes, a finding with as yet uncertain significance. These findings implicate glucose-dependent increases in photoreceptor de novo lipogenesis in the early pathogenesis of DR, although the mechanism of deleterious action of this pathway remains unclear.
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Affiliation(s)
- Rithwick Rajagopal
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Saint Louis, Missouri, USA.
| | - Beau Sylvester
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Saint Louis, Missouri, USA
| | - Sheng Zhang
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Saint Louis, Missouri, USA
| | - Sangeeta Adak
- Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, Saint Louis, Missouri, USA
| | - Xiaochao Wei
- Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, Saint Louis, Missouri, USA
| | - Megan Bowers
- Laboratory of Neural Plasticity, Faculties of Medicine and Science, Brain Research Institute, University of Zurich, Zurich, Switzerland
| | - Sebastian Jessberger
- Laboratory of Neural Plasticity, Faculties of Medicine and Science, Brain Research Institute, University of Zurich, Zurich, Switzerland
| | - Fong-Fu Hsu
- Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, Saint Louis, Missouri, USA
| | - Clay F Semenkovich
- Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, Saint Louis, Missouri, USA; Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, Missouri, USA.
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20
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Zhou Y, Zhou G. Alterations of Lipidomes in Rat Photoreceptor Degeneration Induced by N-Methyl-N-nitrosourea. Lipids 2021; 56:437-448. [PMID: 34058794 DOI: 10.1002/lipd.12306] [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: 03/23/2021] [Accepted: 04/14/2021] [Indexed: 11/11/2022]
Abstract
To investigate alterations of lipidomes in the progress of photoreceptor degeneration induced by N-methyl-N-nitrosourea (MNU) in a rat model, retinal lipid molecular species in adult Sprague-Dawley (SD) rats at 1, 3, and 7 days after MNU administration and age-matched controls were analyzed by the shotgun lipidomics technology. Moreover, total fatty acid levels in retinal, liver, and plasma samples of different groups were determined with gas chromatography. Generally, at day 1, the levels of ethanolamine plasmalogen species in retinas were markedly elevated after treatment with MNU, while the contents of other phospholipids and sphingolipids in the retina were not significantly changed than those of the control group. The compositions of almost all of unsaturated fatty acids in the retina increased significantly at day 1 after MNU administration. At day 7, the MNU treatment group has significant increases in lipid species in the retina. However, the majority of lipids containing docosahexaenoic acid (DHA, 22:6n-3) and docosapentaenoic acid (22:5n-6) declined, especially di-DHA phospholipids were dramatically reduced in the retina. In contrast, similar alterations did not occur in plasma or the liver after MNU treatment. These results suggested that at the early stage of photoreceptor degeneration, lipidome remodeling in the retina might involve protection of photoreceptor from apoptosis and continue their transduction of light. However, at the late stage of photoreceptor apoptosis, increases in comprehensive lipid species occurred, likely due to the myelination of the retina. Finally, the deficiency of DHA in photoreceptor degeneration could exacerbate the influence of myelination on retinal function. We further investigated the effects of unsaturated fatty acids on neuronal apoptosis. The preliminary experiments confirmed our observation from lipidomics analysis that unsaturated fatty acids can protect neurons from apoptosis. Collectively, our study suggests that increased levels of DHA should be protective from photoreceptor degeneration.
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Affiliation(s)
- Yunhua Zhou
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Fudan University, 138 Yi Xue Yuan Road, Shanghai, 200032, China
| | - Guomin Zhou
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Fudan University, 138 Yi Xue Yuan Road, Shanghai, 200032, China
- Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention of Shanghai, 138 Yi Xue Yuan Road, Shanghai, 200032, China
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21
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Abstract
The metabolic syndrome (MetS) is a cluster of cardiovascular risk factors including obesity, insulin resistance (IR) and dyslipidaemia. Consumption of a high-fat diet (HFD) enriched in SFA leads to the accumulation of ceramide (Cer), the central molecule in sphingolipid metabolism. Elevations in plasma and tissue Cer are found in obese individuals, and there is evidence to suggest that Cer lipotoxicity contributes to the MetS. EPA and DHA have shown to improve MetS parameters including IR, inflammation and hypertriacylglycerolaemia; however, whether these improvements are related to Cer is currently unknown. This review examines the potential of EPA and DHA to improve Cer lipotoxicity and MetS parameters including IR, inflammation and dyslipidaemia in vitro and in vivo. Current evidence from cell culture and animal studies indicates that EPA and DHA attenuate palmitate- or HFD-induced Cer lipotoxicity and IR, whereas evidence in humans is greatly lacking. Overall, there is intriguing potential for EPA and DHA to improve Cer lipotoxicity and related MetS parameters, but more research is warranted.
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22
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Jiang M, Huang S, Duan W, Liu Q, Lei M. Alpha-mangostin improves endothelial dysfunction in db/db mice through inhibition of aSMase/ceramide pathway. J Cell Mol Med 2021; 25:3601-3609. [PMID: 33719188 PMCID: PMC8034454 DOI: 10.1111/jcmm.16456] [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: 02/24/2020] [Revised: 02/25/2021] [Accepted: 03/01/2021] [Indexed: 12/16/2022] Open
Abstract
Diabetic vascular complications are the leading causes of death and disability in patients with diabetes. Alpha-mangostin has been reported to have anti-diabetic capacity in recent years. Here, we investigated the protective function of alpha-mangostin on endothelium in vitro and in vivo experiments. We also observed that alpha-mangostin improved impaired endothelium-dependent vasodilation (EDV) of diabetic animals while it limited the aSMase/ceramide pathway and up-regulated eNOS/NO pathway in aortas from diabetic mice. Meanwhile, alpha-mangostin inhibited elevated aSMase/ceramide pathway and reversed impaired EDV induced by high glucose in isolated mouse aortas. In addition, alpha-mangostin increased phosphorylation of eNOS and NO production in high glucose-treated aortas. Alpha-mangostin normalized high glucose-induced activation of aSMase/ceramide pathway and improved eNOS/NO pathway in endothelial cells with high glucose. In conclusion, alpha-mangostin regulates eNOS/NO pathway and improves EDV in aortas of diabetic mice through inhibiting aSMase activity and endogenous ceramide accumulation.
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Affiliation(s)
- Meng Jiang
- Xiangya Hospital of Central South University, Changsha, China
| | - Shanya Huang
- Xiangya Hospital of Central South University, Changsha, China
| | - Wang Duan
- Xiangya Hospital of Central South University, Changsha, China
| | - Qiaoshu Liu
- Xiangya Hospital of Central South University, Changsha, China
| | - Minxiang Lei
- Xiangya Hospital of Central South University, Changsha, China
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23
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Simon MV, Basu SK, Qaladize B, Grambergs R, Rotstein NP, Mandal N. Sphingolipids as critical players in retinal physiology and pathology. J Lipid Res 2021; 62:100037. [PMID: 32948663 PMCID: PMC7933806 DOI: 10.1194/jlr.tr120000972] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 09/04/2020] [Indexed: 12/24/2022] Open
Abstract
Sphingolipids have emerged as bioactive lipids involved in the regulation of many physiological and pathological processes. In the retina, they have been established to participate in numerous processes, such as neuronal survival and death, proliferation and migration of neuronal and vascular cells, inflammation, and neovascularization. Dysregulation of sphingolipids is therefore crucial in the onset and progression of retinal diseases. This review examines the involvement of sphingolipids in retinal physiology and diseases. Ceramide (Cer) has emerged as a common mediator of inflammation and death of neuronal and retinal pigment epithelium cells in animal models of retinopathies such as glaucoma, age-related macular degeneration (AMD), and retinitis pigmentosa. Sphingosine-1-phosphate (S1P) has opposite roles, preventing photoreceptor and ganglion cell degeneration but also promoting inflammation, fibrosis, and neovascularization in AMD, glaucoma, and pro-fibrotic disorders. Alterations in Cer, S1P, and ceramide 1-phosphate may also contribute to uveitis. Notably, use of inhibitors that either prevent Cer increase or modulate S1P signaling, such as Myriocin, desipramine, and Fingolimod (FTY720), preserves neuronal viability and retinal function. These findings underscore the relevance of alterations in the sphingolipid metabolic network in the etiology of multiple retinopathies and highlight the potential of modulating their metabolism for the design of novel therapeutic approaches.
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Affiliation(s)
- M Victoria Simon
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento De Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Argentine National Research Council (CONICET), Bahía Blanca, Argentina
| | - Sandip K Basu
- Departments of Ophthalmology and Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Bano Qaladize
- Departments of Ophthalmology and Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Richard Grambergs
- Departments of Ophthalmology and Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Nora P Rotstein
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento De Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Argentine National Research Council (CONICET), Bahía Blanca, Argentina.
| | - Nawajes Mandal
- Departments of Ophthalmology and Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA.
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24
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Mandal N, Grambergs R, Mondal K, Basu SK, Tahia F, Dagogo-Jack S. Role of ceramides in the pathogenesis of diabetes mellitus and its complications. J Diabetes Complications 2021; 35:107734. [PMID: 33268241 PMCID: PMC8663915 DOI: 10.1016/j.jdiacomp.2020.107734] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 08/24/2020] [Accepted: 08/24/2020] [Indexed: 12/12/2022]
Abstract
Diabetes mellitus (DM) is a systemic metabolic disease that affects 463 million adults worldwide and is a leading cause of cardiovascular disease, blindness, nephropathy, peripheral neuropathy, and lower-limb amputation. Lipids have long been recognized as contributors to the pathogenesis and pathophysiology of DM and its complications, but recent discoveries have highlighted ceramides, a class of bioactive sphingolipids with cell signaling and second messenger capabilities, as particularly important contributors to insulin resistance and the underlying mechanisms of DM complications. Besides their association with insulin resistance and pathophysiology of type 2 diabetes, evidence is emerging that certain species of ceramides are mediators of cellular mechanisms involved in the initiation and progression of microvascular and macrovascular complications of DM. Advances in our understanding of these associations provide unique opportunities for exploring ceramide species as potential novel therapeutic targets and biomarkers. This review discusses the links between ceramides and the pathogenesis of DM and diabetic complications and identifies opportunities for novel discoveries and applications.
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Affiliation(s)
- Nawajes Mandal
- The University of Tennessee Health Science Center, Department of Ophthalmology, Memphis, TN 38163, USA.; The University of Tennessee Health Science Center, Department of Anatomy and Neurobiology, Memphis, TN 38163, USA..
| | - Richard Grambergs
- The University of Tennessee Health Science Center, Department of Ophthalmology, Memphis, TN 38163, USA
| | - Koushik Mondal
- The University of Tennessee Health Science Center, Department of Ophthalmology, Memphis, TN 38163, USA
| | - Sandip K Basu
- The University of Tennessee Health Science Center, Department of Ophthalmology, Memphis, TN 38163, USA
| | - Faiza Tahia
- The University of Tennessee Health Science Center, Department of Ophthalmology, Memphis, TN 38163, USA.; The University of Tennessee Health Science Center, Department of Pharmaceutical Sciences, College of Pharmacy, Memphis, TN 38163, USA
| | - Sam Dagogo-Jack
- The University of Tennessee Health Science Center, Division of Endocrinology, Memphis, TN 38163, USA.; The University of Tennessee Health Science Center, Clinical Research Center, Memphis, TN 38163, USA..
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25
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Busik JV. Lipid metabolism dysregulation in diabetic retinopathy. J Lipid Res 2021; 62:100017. [PMID: 33581416 PMCID: PMC7892987 DOI: 10.1194/jlr.tr120000981] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 12/15/2020] [Accepted: 12/23/2020] [Indexed: 12/12/2022] Open
Abstract
Lipid metabolic abnormalities have emerged as potential risk factors for the development and progression of diabetic complications, including diabetic retinopathy (DR). This review article provides an overview of the results of clinical trials evaluating the potential benefits of lipid-lowering drugs, such as fibrates, omega-3 fatty acids, and statins, for the prevention and treatment of DR. Although several clinical trials demonstrated that treatment with fibrates leads to improvement of DR, there is a dissociation between the protective effects of fibrates in the retina, and the intended blood lipid classes, including plasma triglycerides, total cholesterol, or HDL:LDL cholesterol ratio. Guided by these findings, plasma lipid and lipoprotein-independent mechanisms are addressed based on clinical, cell culture, and animal model studies. Potential retinal-specific effects of fatty acid oxidation products, cholesterol, and ceramide, as well as lipid-independent effects of PPAR alpha activation, are summarized based on the current literature. Overall, this review highlights promising potential of lipid-based treatment strategies further enhanced by the new knowledge of intraretinal lipids and lipoproteins in DR.
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Affiliation(s)
- Julia V Busik
- Department of Physiology, Michigan State University, East Lansing, MI, USA.
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26
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Abstract
Based on clinical findings, diabetic retinopathy (DR) has traditionally been defined as a retinal microvasculopathy. Retinal neuronal dysfunction is now recognized as an early event in the diabetic retina before development of overt DR. While detrimental effects of diabetes on the survival and function of inner retinal cells, such as retinal ganglion cells and amacrine cells, are widely recognized, evidence that photoreceptors in the outer retina undergo early alterations in diabetes has emerged more recently. We review data from preclinical and clinical studies demonstrating a conserved reduction of electrophysiological function in diabetic retinas, as well as evidence for photoreceptor loss. Complementing in vivo studies, we discuss the ex vivo electroretinography technique as a useful method to investigate photoreceptor function in isolated retinas from diabetic animal models. Finally, we consider the possibility that early photoreceptor pathology contributes to the progression of DR, and discuss possible mechanisms of photoreceptor damage in the diabetic retina, such as enhanced production of reactive oxygen species and other inflammatory factors whose detrimental effects may be augmented by phototransduction.
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27
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Tan LX, Germer CJ, La Cunza N, Lakkaraju A. Complement activation, lipid metabolism, and mitochondrial injury: Converging pathways in age-related macular degeneration. Redox Biol 2020; 37:101781. [PMID: 33162377 PMCID: PMC7767764 DOI: 10.1016/j.redox.2020.101781] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 10/22/2020] [Accepted: 10/29/2020] [Indexed: 02/07/2023] Open
Abstract
The retinal pigment epithelium (RPE) is the primary site of injury in non-neovascular age-related macular degeneration or dry AMD. Polymorphisms in genes that regulate complement activation and cholesterol metabolism are strongly associated with AMD, but the biology underlying disease-associated variants is not well understood. Here, we highlight recent studies that have used molecular, biochemical, and live-cell imaging methods to elucidate mechanisms by which aging-associated insults conspire with AMD genetic risk variants to tip the balance towards disease. We discuss how critical functions including lipid metabolism, autophagy, complement regulation, and mitochondrial dynamics are compromised in the RPE, and how a deeper understanding of these mechanisms has helped identify promising therapeutic targets to preserve RPE homeostasis in AMD.
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Affiliation(s)
- Li Xuan Tan
- Department of Ophthalmology, School of Medicine, University of California, San Francisco, CA, USA
| | - Colin J Germer
- Department of Ophthalmology, School of Medicine, University of California, San Francisco, CA, USA; Pharmaceutical Sciences and Pharmacogenomics Graduate Program, University of California, San Francisco, CA, USA
| | - Nilsa La Cunza
- Department of Ophthalmology, School of Medicine, University of California, San Francisco, CA, USA; Pharmaceutical Sciences and Pharmacogenomics Graduate Program, University of California, San Francisco, CA, USA
| | - Aparna Lakkaraju
- Department of Ophthalmology, School of Medicine, University of California, San Francisco, CA, USA; Pharmaceutical Sciences and Pharmacogenomics Graduate Program, University of California, San Francisco, CA, USA; Department of Anatomy, School of Medicine, University of California, San Francisco, CA, USA.
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28
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Levitsky Y, Hammer SS, Fisher KP, Huang C, Gentles TL, Pegouske DJ, Xi C, Lydic TA, Busik JV, Proshlyakov DA. Mitochondrial Ceramide Effects on the Retinal Pigment Epithelium in Diabetes. Int J Mol Sci 2020; 21:E3830. [PMID: 32481596 PMCID: PMC7312467 DOI: 10.3390/ijms21113830] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/24/2020] [Accepted: 05/26/2020] [Indexed: 12/15/2022] Open
Abstract
Mitochondrial damage in the cells comprising inner (retinal endothelial cells) and outer (retinal pigment epithelium (RPE)) blood-retinal barriers (BRB) is known to precede the initial BRB breakdown and further histopathological abnormalities in diabetic retinopathy (DR). We previously demonstrated that activation of acid sphingomyelinase (ASM) is an important early event in the pathogenesis of DR, and recent studies have demonstrated that there is an intricate connection between ceramide and mitochondrial function. This study aimed to determine the role of ASM-dependent mitochondrial ceramide accumulation in diabetes-induced RPE cell damage. Mitochondria isolated from streptozotocin (STZ)-induced diabetic rat retinas (7 weeks duration) showed a 1.64 ± 0.29-fold increase in the ceramide-to-sphingomyelin ratio compared to controls. Conversely, the ceramide-to-sphingomyelin ratio was decreased in the mitochondria isolated from ASM-knockout mouse retinas compared to wild-type littermates, confirming the role of ASM in mitochondrial ceramide production. Cellular ceramide was elevated 2.67 ± 1.07-fold in RPE cells derived from diabetic donors compared to control donors, and these changes correlated with increased gene expression of IL-1β, IL-6, and ASM. Treatment of RPE cells derived from control donors with high glucose resulted in elevated ASM, vascular endothelial growth factor (VEGF), and intercellular adhesion molecule 1 (ICAM-1) mRNA. RPE from diabetic donors showed fragmented mitochondria and a 2.68 ± 0.66-fold decreased respiratory control ratio (RCR). Treatment of immortalized cell in vision research (ARPE-19) cells with high glucose resulted in a 25% ± 1.6% decrease in citrate synthase activity at 72 h. Inhibition of ASM with desipramine (15 μM, 1 h daily) abolished the decreases in metabolic functional parameters. Our results are consistent with diabetes-induced increase in mitochondrial ceramide through an ASM-dependent pathway leading to impaired mitochondrial function in the RPE cells of the retina.
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Affiliation(s)
- Yan Levitsky
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA; (Y.L.); (S.S.H.); (K.P.F.); (C.H.); (T.L.G.); (T.A.L.)
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA; (D.J.P.); (C.X.)
| | - Sandra S. Hammer
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA; (Y.L.); (S.S.H.); (K.P.F.); (C.H.); (T.L.G.); (T.A.L.)
| | - Kiera P. Fisher
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA; (Y.L.); (S.S.H.); (K.P.F.); (C.H.); (T.L.G.); (T.A.L.)
| | - Chao Huang
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA; (Y.L.); (S.S.H.); (K.P.F.); (C.H.); (T.L.G.); (T.A.L.)
| | - Travan L. Gentles
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA; (Y.L.); (S.S.H.); (K.P.F.); (C.H.); (T.L.G.); (T.A.L.)
| | - David J. Pegouske
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA; (D.J.P.); (C.X.)
| | - Caimin Xi
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA; (D.J.P.); (C.X.)
| | - Todd A. Lydic
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA; (Y.L.); (S.S.H.); (K.P.F.); (C.H.); (T.L.G.); (T.A.L.)
| | - Julia V. Busik
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA; (Y.L.); (S.S.H.); (K.P.F.); (C.H.); (T.L.G.); (T.A.L.)
| | - Denis A. Proshlyakov
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA; (D.J.P.); (C.X.)
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29
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Huang C, Fisher KP, Hammer SS, Busik JV. Extracellular Vesicle-Induced Classical Complement Activation Leads to Retinal Endothelial Cell Damage via MAC Deposition. Int J Mol Sci 2020; 21:ijms21051693. [PMID: 32121610 PMCID: PMC7084203 DOI: 10.3390/ijms21051693] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 02/27/2020] [Indexed: 12/11/2022] Open
Abstract
Several studies have suggested that there is a link between membrane attack complex (MAC) deposition in the retina and the progression of diabetic retinopathy (DR). Our recent investigation demonstrated that circulating IgG-laden extracellular vesicles contribute to an increase in retinal vascular permeability in DR through activation of the complement system. However, the mechanism through which extracellular vesicle-induced complement activation contributes to retinal vascular cytolytic damage in DR is not well understood. In this study, we demonstrate that IgG-laden extracellular vesicles in rat plasma activate the classical complement pathway, and in vitro Streptozotocin (STZ)-induced rat diabetic plasma results in MAC deposition and cytolytic damage in human retinal endothelial cells (HRECs). Moreover, removal of the plasma extracellular vesicles reduced the MAC deposition and abrogated cytolytic damage seen in HRECs. Together, the results of this study demonstrate that complement activation by IgG-laden extracellular vesicles in plasma could lead to MAC deposition and contribute to endothelium damage and progression of DR.
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30
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Li Y, Lu Z, Zhang L, Kirkwood KL, Lopes-Virella MF, Huang Y. Acid sphingomyelinase deficiency exacerbates LPS-induced experimental periodontitis. Oral Dis 2019; 26:637-646. [PMID: 31883406 DOI: 10.1111/odi.13268] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 11/11/2019] [Accepted: 12/06/2019] [Indexed: 12/29/2022]
Abstract
BACKGROUND Mutation of the gene for acid sphingomyelinase (ASMase) causes Niemann-Pick disease. However, the effect of ASMase deficiency on periodontal health is unknown. Periodontal disease is a disease resulting from infection and inflammation of periodontal tissue and alveolar bone that support the teeth. The goal of this study was to determine the role of ASMase deficiency in periodontal inflammation and alveolar bone loss. METHODS We induced periodontitis in wild-type and ASMase-deficient (ASMase-/- ) mice with periodontal lipopolysaccharide (LPS) injection and compared the alveolar bone loss and periodontal inflammation between these mice. RESULTS Results showed that ASMase deficiency did not significantly change metabolic parameters, but exacerbated LPS-induced alveolar bone loss, osteoclastogenesis, and periodontal tissue inflammation. To understand the mechanisms by which ASMase deficiency aggravates LPS-induced periodontitis, we analyzed sphingolipids in periodontal tissues. Results showed that ASMase deficiency led to increases in not only sphingomyelin, but also ceramide (CER), a bioactive sphingolipid known to promote inflammation. Results further showed that ASMase deficiency increased CER de novo synthesis. CONCLUSION ASMase deficiency exacerbated LPS-induced alveolar bone loss and periodontal inflammation. ASMase deficiency leads to an unexpected CER increase by stimulating de novo synthesis CER, which is likely to be involved in the ASMase deficiency-exacerbated periodontitis.
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Affiliation(s)
- Yanchun Li
- Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, College of Medicine, Medical University of South Carolina, Charleston, South Carolina
| | - Zhongyang Lu
- Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, College of Medicine, Medical University of South Carolina, Charleston, South Carolina
| | - Lixia Zhang
- Departments of Oral Biology, School of Dental Medicine, University at Buffalo, Buffalo, New York
| | - Keith L Kirkwood
- Departments of Oral Biology, School of Dental Medicine, University at Buffalo, Buffalo, New York.,Department of Oral Oncology, Roswell Park Comprehensive Cancer Center, Buffalo, New York
| | - Maria F Lopes-Virella
- Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, College of Medicine, Medical University of South Carolina, Charleston, South Carolina.,Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina
| | - Yan Huang
- Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, College of Medicine, Medical University of South Carolina, Charleston, South Carolina.,Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina
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31
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Levitsky Y, Pegouske DJ, Hammer SS, Frantz NL, Fisher KP, Muchnik AB, Saripalli AR, Kirschner P, Bazil JN, Busik JV, Proshlyakov DA. Micro-respirometry of whole cells and isolated mitochondria. RSC Adv 2019; 9:33257-33267. [PMID: 32123561 PMCID: PMC7051014 DOI: 10.1039/c9ra05289e] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Oxygen consumption is a key metric of metabolism in aerobic organisms. Current respirometric methods led to seminal discoveries despite limitations such as high sample demand, exchange with atmospheric O2, and cumulative titration protocols leading to limited choice of useable tissue, complex data interpretation, and restricted experimental design. We developed a sensitive and customizable method of measuring O2 consumption rates by a variety of biological samples in microliter volumes without interference from the aerobic environment. We demonstrate that O2 permeability of the photopolymer, VeroClear, is comparable to that of polyetheretherketone (0.125 vs. 0.143 barrer, respectively) providing an efficient barrier to oxygen ingress. Optical transparency of VeroClear, combined with high resolution 3D printing, allows for optode-based oxygen detection in enclosed samples. These properties yield a microrespirometer with over 100× dynamic range for O2 consumption rates. Importantly, the enclosed respirometer configuration and very low oxygen permeability of materials makes it suitable, with resin pre-conditioning, for quantitative assessment of O2 consumption rates at any desired [O2], including hyperbaric, physiological or hypoxic conditions as necessary for each cell type. We characterized two configurations to study soluble enzymes, isolated mitochondria, cells in suspension, and adherent cells cultured on-chip. Improved sensitivity allows for routine quantitative detection of respiration by as few as several hundred cells. Specific activity of cell suspensions in the microrespirometer was in close agreement with that obtained by high-resolution polarographic respirometry. Adherent cell protocols allowed for physiologically relevant assessment of respiration in retinal pigment epithelial cells, ARPE-19, which displayed lower metabolic rates compared with those in suspension. By exchanging medium composition, we demonstrate that cells can be transiently inhibited by cyanide and that 99.6% of basal O2 uptake is recovered upon its removal. This approach is amenable to new experimental designs and precision measurements on limited sample quantities across basic research and applied fields. 3D printed microfluidic respirometer allows for quantitative investigation of biological energy transduction in adherent and suspension samples.![]()
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Affiliation(s)
- Yan Levitsky
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, MI 48824, USA.,Department of Physiology, Michigan State University, East Lansing, MI, USA
| | - David J Pegouske
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, MI 48824, USA
| | - Sandra S Hammer
- Department of Physiology, Michigan State University, East Lansing, MI, USA
| | - Nathan L Frantz
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, MI 48824, USA
| | - Kiera P Fisher
- Department of Physiology, Michigan State University, East Lansing, MI, USA
| | - Artem B Muchnik
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, MI 48824, USA
| | | | - Philip Kirschner
- Department of Physiology, Michigan State University, East Lansing, MI, USA
| | - Jason N Bazil
- Department of Physiology, Michigan State University, East Lansing, MI, USA
| | - Julia V Busik
- Department of Physiology, Michigan State University, East Lansing, MI, USA
| | - Denis A Proshlyakov
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, MI 48824, USA
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32
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Fu Z, Chen CT, Cagnone G, Heckel E, Sun Y, Cakir B, Tomita Y, Huang S, Li Q, Britton W, Cho SS, Kern TS, Hellström A, Joyal JS, Smith LE. Dyslipidemia in retinal metabolic disorders. EMBO Mol Med 2019; 11:e10473. [PMID: 31486227 PMCID: PMC6783651 DOI: 10.15252/emmm.201910473] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 06/10/2019] [Accepted: 08/15/2019] [Indexed: 12/24/2022] Open
Abstract
The light‐sensitive photoreceptors in the retina are extremely metabolically demanding and have the highest density of mitochondria of any cell in the body. Both physiological and pathological retinal vascular growth and regression are controlled by photoreceptor energy demands. It is critical to understand the energy demands of photoreceptors and fuel sources supplying them to understand neurovascular diseases. Retinas are very rich in lipids, which are continuously recycled as lipid‐rich photoreceptor outer segments are shed and reformed and dietary intake of lipids modulates retinal lipid composition. Lipids (as well as glucose) are fuel substrates for photoreceptor mitochondria. Dyslipidemia contributes to the development and progression of retinal dysfunction in many eye diseases. Here, we review photoreceptor energy demands with a focus on lipid metabolism in retinal neurovascular disorders.
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Affiliation(s)
- Zhongjie Fu
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA.,Manton Center for Orphan Disease, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - Chuck T Chen
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Gael Cagnone
- Department of Pediatrics, Pharmacology and Ophthalmology, CHU Sainte-Justine Research Center, Université de Montréal, Montreal, QC, Canada.,Department of Pharmacology and Therapeutics, University of Montreal, Montreal, QC, Canada
| | - Emilie Heckel
- Department of Pediatrics, Pharmacology and Ophthalmology, CHU Sainte-Justine Research Center, Université de Montréal, Montreal, QC, Canada.,Department of Pharmacology and Therapeutics, University of Montreal, Montreal, QC, Canada
| | - Ye Sun
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - Bertan Cakir
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - Yohei Tomita
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - Shuo Huang
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - Qian Li
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - William Britton
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - Steve S Cho
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - Timothy S Kern
- Center for Translational Vision Research, Gavin Herbert Eye Institute, Irvine, CA, USA
| | - Ann Hellström
- Section for Ophthalmology, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden
| | - Jean-Sébastien Joyal
- Department of Pediatrics, Pharmacology and Ophthalmology, CHU Sainte-Justine Research Center, Université de Montréal, Montreal, QC, Canada.,Department of Pharmacology and Therapeutics, University of Montreal, Montreal, QC, Canada
| | - Lois Eh Smith
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
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Kern TS, Antonetti DA, Smith LEH. Pathophysiology of Diabetic Retinopathy: Contribution and Limitations of Laboratory Research. Ophthalmic Res 2019; 62:196-202. [PMID: 31362288 PMCID: PMC6872907 DOI: 10.1159/000500026] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 03/29/2019] [Indexed: 12/11/2022]
Abstract
Preclinical models of diabetic retinopathy are indispensable in the drug discovery and development of new therapies. They are, however, imperfect facsimiles of diabetic retinopathy in humans. This chapter discusses the advantages, limitations, and physiological and pathological relevance of preclinical models of diabetic retinopathy. The judicious interpretation and extrapolation of data derived from these models to humans and a correspondingly greater emphasis placed on translational medical research in early-stage clinical trials are essential to more successfully inhibit the development and progression of diabetic retinopathy in the future.
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Affiliation(s)
- Timothy S Kern
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA,
- Veterans Administration Medical Center Research Service 151, Cleveland, Ohio, USA,
| | - David A Antonetti
- Kellogg Eye Center, Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan, USA
| | - Lois E H Smith
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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Simón MV, Prado Spalm FH, Vera MS, Rotstein NP. Sphingolipids as Emerging Mediators in Retina Degeneration. Front Cell Neurosci 2019; 13:246. [PMID: 31244608 PMCID: PMC6581011 DOI: 10.3389/fncel.2019.00246] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 05/17/2019] [Indexed: 12/12/2022] Open
Abstract
The sphingolipids ceramide (Cer), sphingosine-1-phosphate (S1P), sphingosine (Sph), and ceramide-1-phosphate (C1P) are key signaling molecules that regulate major cellular functions. Their roles in the retina have gained increasing attention during the last decade since they emerge as mediators of proliferation, survival, migration, neovascularization, inflammation and death in retina cells. As exacerbation of these processes is central to retina degenerative diseases, they appear as crucial players in their progression. This review analyzes the functions of these sphingolipids in retina cell types and their possible pathological roles. Cer appears as a key arbitrator in diverse retinal pathologies; it promotes inflammation in endothelial and retina pigment epithelium (RPE) cells and its increase is a common feature in photoreceptor death in vitro and in animal models of retina degeneration; noteworthy, inhibiting Cer synthesis preserves photoreceptor viability and functionality. In turn, S1P acts as a double edge sword in the retina. It is essential for retina development, promoting the survival of photoreceptors and ganglion cells and regulating proliferation and differentiation of photoreceptor progenitors. However, S1P has also deleterious effects, stimulating migration of Müller glial cells, angiogenesis and fibrosis, contributing to the inflammatory scenario of proliferative retinopathies and age related macular degeneration (AMD). C1P, as S1P, promotes photoreceptor survival and differentiation. Collectively, the expanding role for these sphingolipids in the regulation of critical processes in retina cell types and in their dysregulation in retina degenerations makes them attractive targets for treating these diseases.
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Affiliation(s)
- M Victoria Simón
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento De Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Argentine National Research Council (CONICET), Bahía Blanca, Argentina
| | - Facundo H Prado Spalm
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento De Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Argentine National Research Council (CONICET), Bahía Blanca, Argentina
| | - Marcela S Vera
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento De Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Argentine National Research Council (CONICET), Bahía Blanca, Argentina
| | - Nora P Rotstein
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento De Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Argentine National Research Council (CONICET), Bahía Blanca, Argentina
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Glaser UG, Fandrey J. Sphingolipids in inflammatory hypoxia. Biol Chem 2019; 399:1169-1174. [PMID: 29908122 DOI: 10.1515/hsz-2018-0173] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 05/04/2018] [Indexed: 12/30/2022]
Abstract
Hypoxia due to rapid tumor growth with impaired neovascularization and inflammation resulting from immune cell activation are hallmarks of cancer. Hypoxia-inducible factors control transcriptional adaptation in response to low oxygen conditions, both in tumor and immune cells. In addition, sphingolipids become increasingly recognized as important cell mediators in tumor and inflammatory hypoxia. Recent studies have identified acid sphingomyelinase (ASM), a central enzyme in the sphingolipid metabolism, as a regulator of several types of stress stimuli pathways and an important player in the tumor microenvironment. Therefore, this review will address the connection between the hypoxic response and the ASM/ceramide system in the context of inflammatory hypoxia.
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Affiliation(s)
- Ulrike G Glaser
- Institut für Physiologie, Universität Duisburg-Essen, D-45122 Essen, Germany
| | - Joachim Fandrey
- Institut für Physiologie, Universität Duisburg-Essen, D-45122 Essen, Germany
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36
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Inhibition of acid sphingomyelinase activity ameliorates endothelial dysfunction in db/db mice. Biosci Rep 2019; 39:BSR20182144. [PMID: 30910852 PMCID: PMC6481240 DOI: 10.1042/bsr20182144] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 02/19/2019] [Accepted: 03/15/2019] [Indexed: 12/25/2022] Open
Abstract
Acid sphingomyelinase (aSMase) plays an important role in endothelial dysfunction. Here, we show that elevated aSMase activity and ceramide content were reduced by desipramine treatment in diabetic animals. The inhibitor of aSMase, desipramine, improved vascular dysfunction in db/db mice. High glucose (HG)-induced up-regulation of aSMase activity and ceramide levels were restored by treatment with aSMase siRNA or desipramine in endothelial cells. In addition, aSMase siRNA or desipramine treatment increased the release of nitric oxide (NO) and the phosphorylation of endothelial NO synthase (eNOS) in diabetic mouse aortas and aortic endothelial cells with HG. These results indicate that inhibition of aSMase/ceramide pathway improves endothelium-dependent vascular relaxation (EDR) largely through regulating the eNOS/NO pathway in diabetic animals.
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Role of Bioactive Sphingolipids in Inflammation and Eye Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1161:149-167. [PMID: 31562629 DOI: 10.1007/978-3-030-21735-8_14] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Inflammation is a common underlying factor in a diversity of ocular diseases, ranging from macular degeneration, autoimmune uveitis, glaucoma, diabetic retinopathy and microbial infection. In addition to the variety of known cellular mediators of inflammation, such as cytokines, chemokines and lipid mediators, there is now considerable evidence that sphingolipid metabolites also play a central role in the regulation of inflammatory pathways. Various sphingolipid metabolites, such as ceramide (Cer), ceramide-1-phosphate (C1P), sphingosine-1-phosphate (S1P), and lactosylceramide (LacCer) can contribute to ocular inflammatory diseases through multiple pathways. For example, inflammation generates Cer from sphingomyelins (SM) in the plasma membrane, which induces death receptor ligand formation and leads to apoptosis of retinal pigment epithelial (RPE) and photoreceptor cells. Inflammatory stress by reactive oxygen species leads to LacCer accumulation and S1P secretion and induces proliferation of retinal endothelial cells and eventual formation of new vessels. In sphingolipid/lysosomal storage disorders, sphingolipid metabolites accumulate in lysosomes and can cause ocular disorders that have an inflammatory etiology. Sphingolipid metabolites activate complement factors in the immune-response mediated pathogenesis of macular degeneration. These examples highlight the integral association between sphingolipids and inflammation in ocular diseases.
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Inflammatory Ocular Diseases and Sphingolipid Signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1159:139-152. [DOI: 10.1007/978-3-030-21162-2_8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Sphingomyelin phosphodiesterase 1 (SMPD1) mediates the attenuation of myocardial infarction-induced cardiac fibrosis by astaxanthin. Biochem Biophys Res Commun 2018; 503:637-643. [PMID: 29906461 DOI: 10.1016/j.bbrc.2018.06.054] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 06/11/2018] [Indexed: 12/27/2022]
Abstract
Uncontrolled cardiac fibrosis following myocardial infarction (MI) is a critical pathological change leading to heart failure. Current pharmacotherapies are limited by unsatisfactory efficacy and undesired systemic side effects. Astaxanthin (ASX) is a natural carotenoid with strong antioxidant and anti-inflammatory activities. The effects of ASX on MI-induced cardiac fibrosis and the underlying mechanisms remain largely unknown. In this study, after the establishment of MI model, mice were administrated with ASX (200 mg/kg⋅d) for 4 weeks. We found that ASX treatment attenuated cardiac fibrosis and improved heart function following MI, as evidenced by reduced collagen I/III ratio, hydroxyproline content and left ventricular end diastolic pressure (LVEDP). Lipidomic analysis revealed the overaccumulation of myocardial ceramides in mice with cardiac fibrosis, which was normalized by ASX treatment. Molecular docking analysis showed that ASX produced a tight fit in the pocket of sphingomyelin phosphodiesterase 1 (SMPD1), a key enzyme in the production of ceramides. Western blot analysis confirmed the significant inhibition of SMPD1 expression by ASX. Furthermore, MI-induced overexpression of transforming growth factor β1 (TGF-β1) and phosphorylated SMAD2/3 were attenuated by ASX administration. SMPD1 knockout (KO) abrogated the beneficial effect of ASX. Taken together, our results suggest that the cardioprotective effects of ASX are mediated by SMPD1 through the indirection inhibition of TGF- β1/SMAD signaling cascade.
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40
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Kady NM, Liu X, Lydic TA, Syed MH, Navitskaya S, Wang Q, Hammer SS, O'Reilly S, Huang C, Seregin SS, Amalfitano A, Chiodo VA, Boye SL, Hauswirth WW, Antonetti DA, Busik JV. ELOVL4-Mediated Production of Very Long-Chain Ceramides Stabilizes Tight Junctions and Prevents Diabetes-Induced Retinal Vascular Permeability. Diabetes 2018; 67:769-781. [PMID: 29362226 PMCID: PMC5860862 DOI: 10.2337/db17-1034] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 01/08/2018] [Indexed: 12/25/2022]
Abstract
Tight junctions (TJs) involve close apposition of transmembrane proteins between cells. Although TJ proteins have been studied in detail, the role of lipids is largely unknown. We addressed the role of very long-chain (VLC ≥26) ceramides in TJs using diabetes-induced loss of the blood-retinal barrier as a model. VLC fatty acids that incorporate into VLC ceramides are produced by elongase elongation of very long-chain fatty acids protein 4 (ELOVL4). ELOVL4 is significantly reduced in the diabetic retina. Overexpression of ELOVL4 significantly decreased basal permeability, inhibited vascular endothelial growth factor (VEGF)- and interleukin-1β-induced permeability, and prevented VEGF-induced decrease in occludin expression and border staining of TJ proteins ZO-1 and claudin-5. Intravitreal delivery of AAV2-hELOVL4 reduced diabetes-induced increase in vascular permeability. Ultrastructure and lipidomic analysis revealed that ω-linked acyl-VLC ceramides colocalize with TJ complexes. Overall, normalization of retinal ELOVL4 expression could prevent blood-retinal barrier dysregulation in diabetic retinopathy through an increase in VLC ceramides and stabilization of TJs.
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Affiliation(s)
- Nermin M Kady
- Department of Physiology, Michigan State University, East Lansing, MI
| | - Xuwen Liu
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI
| | - Todd A Lydic
- Department of Physiology, Michigan State University, East Lansing, MI
| | - Meesum H Syed
- Department of Physiology, Michigan State University, East Lansing, MI
| | | | - Qi Wang
- Department of Physiology, Michigan State University, East Lansing, MI
| | - Sandra S Hammer
- Department of Physiology, Michigan State University, East Lansing, MI
| | - Sandra O'Reilly
- Department of Physiology, Michigan State University, East Lansing, MI
| | - Chao Huang
- Department of Physiology, Michigan State University, East Lansing, MI
| | - Sergey S Seregin
- Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, MI
| | - Andrea Amalfitano
- Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, MI
| | - Vince A Chiodo
- Ophthalmology and Molecular Genetics and Retina Gene Therapy Group, University of Florida, Gainesville, FL
| | - Sanford L Boye
- Ophthalmology and Molecular Genetics and Retina Gene Therapy Group, University of Florida, Gainesville, FL
| | - William W Hauswirth
- Ophthalmology and Molecular Genetics and Retina Gene Therapy Group, University of Florida, Gainesville, FL
| | - David A Antonetti
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI
| | - Julia V Busik
- Department of Physiology, Michigan State University, East Lansing, MI
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Kowluru RA, Mishra M. Therapeutic targets for altering mitochondrial dysfunction associated with diabetic retinopathy. Expert Opin Ther Targets 2018; 22:233-245. [PMID: 29436254 PMCID: PMC6088375 DOI: 10.1080/14728222.2018.1439921] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Retinopathy remains as one of the most feared blinding complications of diabetes, and with the prevalence of this life-long disease escalating at an alarming rate, the incidence of retinopathy is also climbing. Although the cutting edge research has identified many molecular mechanisms associated with its development, the exact mechanism how diabetes damages the retina remains obscure, limiting therapeutic options for this devastating disease. Areas covered: This review focuses on the central role of mitochondrial dysfunction/damage in the pathogenesis of diabetic retinopathy, and how damaged mitochondria initiates a self-perpetuating vicious cycles of free radicals. We have also reviewed how mitochondria could serve as a therapeutic target, and the challenges associated with the complex double mitochondrial membranes and a well-defined blood-retinal barrier for optimal pharmacologic/molecular approach to improve mitochondrial function. Expert opinion: Mitochondrial dysfunction provides many therapeutic targets for ameliorating the development of diabetic retinopathy including their biogenesis, DNA damage and epigenetic modifications. New technology to enhance pharmaceuticals uptake inside the mitochondria, nanotechnology to deliver drugs to the retina, and maintenance of mitochondrial homeostasis via lifestyle changes and novel therapeutics to prevent epigenetic modifications, could serve as some of the welcoming avenues for a diabetic patient to target this sight-threatening disease.
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Affiliation(s)
- Renu A Kowluru
- a Department of Ophthalmology, Kresge Eye Institute , Wayne State University , Detroit , MI , USA
| | - Manish Mishra
- a Department of Ophthalmology, Kresge Eye Institute , Wayne State University , Detroit , MI , USA
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Liu T, Duan W, Nizigiyimana P, Gao L, Liao Z, Xu B, Liu L, Lei M. Alpha-mangostin attenuates diabetic nephropathy in association with suppression of acid sphingomyelianse and endoplasmic reticulum stress. Biochem Biophys Res Commun 2018; 496:394-400. [PMID: 29317203 DOI: 10.1016/j.bbrc.2018.01.040] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 01/05/2018] [Indexed: 01/28/2023]
Abstract
AIMS Diabetic nephropathy is a common complication of diabetes, but there are currently few treatment options. The aim of this study was to gain insight into the effect of alpha-mangostin on diabetic nephropathy and possible related mechanisms. METHODS Goto-Kakizaki rats were used as a diabetic model and received alpha-mangostin or desipramine treatment with normal saline as a control. Ten age-matched Sprague Dawley rats were used as normal controls and treated with normal saline. At week 12, blood glucose, albuminuria, apoptosis and renal pathologic changes were assessed. Protein levels for acid sphingomyelinase, glucose-regulated protein 78, phosphorylated PKR-like ER-resident kinase, activated transcription factor 4, CCAAT/enhancer-binding protein, homologous protein), and cleaved-caspase12 were measured. RESULTS The level of acid sphingomyelinase was significantly increased, and ER stress was activated in diabetic rat kidneys when compared to the control animals. When acid sphingomyelinase was inhibited by alpha-mangostin, the expression of ER stress-related proteins was down-regulated in association with decreased levels of diabetic kidney injury. CONCLUSIONS Alpha-mangostin, an acid sphingomyelinase inhibitor plays a protective role in diabetic neuropathy by relieving ER stress induced-renal cell apoptosis.
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Affiliation(s)
- Tingting Liu
- Department of Endocrinology, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China; Department of Endocrinology, Haikou People's Hospital, Haikou, Hainan, 570208, China
| | - Wang Duan
- Department of Endocrinology, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
| | - Paul Nizigiyimana
- Department of Endocrinology, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
| | - Lin Gao
- Department of Endocrinology, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
| | - Zhouning Liao
- Department of Endocrinology, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
| | - Boya Xu
- Department of Endocrinology, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
| | - Lerong Liu
- Department of Endocrinology, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
| | - Minxiang Lei
- Department of Endocrinology, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China.
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Bhatwadekar AD, Duan Y, Korah M, Thinschmidt JS, Hu P, Leley SP, Caballero S, Shaw L, Busik J, Grant MB. Hematopoietic stem/progenitor involvement in retinal microvascular repair during diabetes: Implications for bone marrow rejuvenation. Vision Res 2017; 139:211-220. [PMID: 29042190 DOI: 10.1016/j.visres.2017.06.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 05/31/2017] [Accepted: 06/02/2017] [Indexed: 02/07/2023]
Abstract
The widespread nature of diabetes affects all organ systems of an individual including the bone marrow. Long-term damage to the cellular and extracellular components of the bone marrow leads to a rapid decline in the bone marrow-hematopoietic stem/progenitor cells (HS/PCs) compartment. This review will highlight the importance of bone marrow microenvironment in maintaining bone marrow HS/PC populations and the contribution of these key populations in microvascular repair during the natural history of diabetes. The autonomic nervous system can initiate and propagate bone marrow dysfunction in diabetes. Systemic pharmacological strategies designed to protect the bone marrow-HS/PC population from diabetes induced-oxidative stress and advanced glycation end product accumulation represent a new approach to target diabetic retinopathy progression. Protecting HS/PCs ensures their participation in vascular repair and reduces the risk of vasogdegeneration occurring in the retina.
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Affiliation(s)
- Ashay D Bhatwadekar
- Department of Ophthalmology, Indiana University, Indianapolis, IN 46202, USA.
| | - Yaqian Duan
- Department of Ophthalmology, Indiana University, Indianapolis, IN 46202, USA
| | - Maria Korah
- Department of Pharmacology, University of Florida, Gainesville, FL 32610, USA
| | | | - Ping Hu
- Department of Ophthalmology, Indiana University, Indianapolis, IN 46202, USA
| | - Sameer P Leley
- Department of Ophthalmology, Indiana University, Indianapolis, IN 46202, USA
| | - Sergio Caballero
- Department of Pharmacology, University of Florida, Gainesville, FL 32610, USA
| | - Lynn Shaw
- Department of Ophthalmology, Indiana University, Indianapolis, IN 46202, USA
| | - Julia Busik
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | - Maria B Grant
- Department of Ophthalmology, Indiana University, Indianapolis, IN 46202, USA.
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Hammer SS, Beli E, Kady N, Wang Q, Wood K, Lydic TA, Malek G, Saban DR, Wang XX, Hazra S, Levi M, Busik JV, Grant MB. The Mechanism of Diabetic Retinopathy Pathogenesis Unifying Key Lipid Regulators, Sirtuin 1 and Liver X Receptor. EBioMedicine 2017; 22:181-190. [PMID: 28774737 PMCID: PMC5552206 DOI: 10.1016/j.ebiom.2017.07.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 07/06/2017] [Accepted: 07/07/2017] [Indexed: 12/30/2022] Open
Abstract
Diabetic retinopathy (DR) is a complication secondary to diabetes and is the number one cause of blindness among working age individuals worldwide. Despite recent therapeutic breakthroughs using pharmacotherapy, a cure for DR has yet to be realized. Several clinical trials have highlighted the vital role dyslipidemia plays in the progression of DR. Additionally, it has recently been shown that activation of Liver X receptor (LXRα/LXRβ) prevents DR in diabetic animal models. LXRs are nuclear receptors that play key roles in regulating cholesterol metabolism, fatty acid metabolism and inflammation. In this manuscript, we show insight into DR pathogenesis by demonstrating an innovative signaling axis that unifies key metabolic regulators, Sirtuin 1 and LXR, in modulating retinal cholesterol metabolism and inflammation in the diabetic retina. Expression of both regulators, Sirtuin 1 and LXR, are significantly decreased in diabetic human retinal samples and in a type 2 diabetic animal model. Additionally, activation of LXR restores reverse cholesterol transport, prevents inflammation, reduces pro-inflammatory macrophages activity and prevents the formation of diabetes-induced acellular capillaries. Taken together, the work presented in this manuscript highlights the important role lipid dysregulation plays in DR progression and offers a novel potential therapeutic target for the treatment of DR. Diabetes affects retinal Liver X Receptor and Sirtuin 1 expression levels. Liver X Receptor normalized reverse cholesterol transport and prevented diabetes-induced inflammation in retinal cells. Liver X Receptor activation reduced the number of pro-inflammatory macrophages and prevented DR-like pathology.
Results of recent clinical trials demonstrate strong association between lipid abnormalities and progression of diabetic retinopathy (DR), the sight-threatening secondary complication of diabetes. This study addresses the role of key metabolic lipid regulators, SIRT1 and LXR in the progression of DR. All the components of SIRT1-LXR axis were downregulated in retinal cells isolated from human donor tissue or a DR animal model. Activation of LXR normalized reverse cholesterol transport, prevented diabetes-induced inflammation, reduced the number of pro-inflammatory macrophages and prevented DR-like pathology, suggesting that control of SIRT1-LXR axis could be a promising therapeutic target for treatment of DR.
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Affiliation(s)
- Sandra S Hammer
- Department of Physiology, Michigan State University, East Lansing, MI, United States
| | - Eleni Beli
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Nermin Kady
- Department of Physiology, Michigan State University, East Lansing, MI, United States
| | - Qi Wang
- Department of Physiology, Michigan State University, East Lansing, MI, United States
| | - Kiana Wood
- Department of Physiology, Michigan State University, East Lansing, MI, United States
| | - Todd A Lydic
- Department of Physiology, Michigan State University, East Lansing, MI, United States
| | - Goldis Malek
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC, United States
| | - Daniel R Saban
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC, United States
| | - Xiaoxin X Wang
- Department of Medicine, University of Colorado, Aurora, CO, United States
| | - Sugata Hazra
- Department of Pharmacology, University of Florida, Gainesville, FL, United States
| | - Moshe Levi
- Department of Medicine, University of Colorado, Aurora, CO, United States
| | - Julia V Busik
- Department of Physiology, Michigan State University, East Lansing, MI, United States.
| | - Maria B Grant
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN, United States.
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Hammer SS, Busik JV. The role of dyslipidemia in diabetic retinopathy. Vision Res 2017; 139:228-236. [PMID: 28545981 DOI: 10.1016/j.visres.2017.04.010] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 04/06/2017] [Accepted: 04/13/2017] [Indexed: 02/08/2023]
Abstract
Diabetic retinopathy (DR) affects over 93million people worldwide and is the number one cause of blindness among working age adults. These indicators coupled with the projected rise of patients diagnosed with diabetes, makes DR a serious and prevalent vision threating disease. Data from recent clinical trials demonstrate that in addition to the well accepted role of hyperglycemia, dyslipidemia is an important, but often overlooked factor in the development of DR. The central aim of this review article is to showcase the critical role of dyslipidemia in DR progression as well as highlight novel therapeutic solutions that take advantage of the vital roles lipid metabolism plays in DR progression.
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Affiliation(s)
- Sandra S Hammer
- Department of Physiology, Michigan State University, East Lansing, MI, United States
| | - Julia V Busik
- Department of Physiology, Michigan State University, East Lansing, MI, United States.
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Fan J, Wu BX, Crosson CE. Suppression of Acid Sphingomyelinase Protects the Retina from Ischemic Injury. Invest Ophthalmol Vis Sci 2017; 57:4476-84. [PMID: 27571014 PMCID: PMC5015980 DOI: 10.1167/iovs.16-19717] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
PURPOSE Acid sphingomyelinase (ASMase) catalyzes the hydrolysis of sphingomyelin to ceramide and mediates multiple responses involved in inflammatory and apoptotic signaling. However, the role ASMase plays in ischemic retinal injury has not been investigated. The purpose of this study was to investigate how reduced ASMase expression impacts retinal ischemic injury. METHODS Changes in ceramide levels and ASMase activity were determined by high performance liquid chromatography-tandem mass spectrometry analysis and ASMase activity. Retinal function and morphology were assessed by electroretinography (ERG) and morphometric analyses. Levels of TNF-α were determined by ELISA. Activation of p38 MAP kinase was assessed by Western blot analysis. RESULTS In wild-type mice, ischemia produced a significant increase in retinal ASMase activity and ceramide levels. These increases were associated with functional deficits as measured by ERG analysis and significant structural degeneration in most retinal layers. In ASMase+/- mice, retinal ischemia did not significantly alter ASMase activity, and the rise in ceramide levels were significantly reduced compared to levels in retinas from wild-type mice. In ASMase+/- mice, functional and morphometric analyses of ischemic eyes revealed significantly less retinal degeneration than in injured retinas from wild-type mice. The ischemia-induced increase in retinal TNF-α levels was suppressed by the administration of the ASMase inhibitor desipramine, or by reducing ASMase expression. CONCLUSIONS Our results demonstrate that reducing ASMase expression provides partial protection from ischemic injury. Hence, the production of ceramide and subsequent mediators plays a role in the development of ischemic retinal injury. Modulating ASMase may present new opportunities for adjunctive therapies when treating retinal ischemic disorders.
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Affiliation(s)
- Jie Fan
- Storm Eye Institute Medical University of South Carolina, Department of Ophthalmology, Charleston, South Carolina, United States
| | - Bill X Wu
- Departments of Immunology and Microbiology, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Craig E Crosson
- Storm Eye Institute Medical University of South Carolina, Department of Ophthalmology, Charleston, South Carolina, United States
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Kady N, Yan Y, Salazar T, Wang Q, Chakravarthy H, Huang C, Beli E, Navitskaya S, Grant M, Busik J. Increase in acid sphingomyelinase level in human retinal endothelial cells and CD34 + circulating angiogenic cells isolated from diabetic individuals is associated with dysfunctional retinal vasculature and vascular repair process in diabetes. J Clin Lipidol 2017; 11:694-703. [PMID: 28457994 PMCID: PMC5492962 DOI: 10.1016/j.jacl.2017.03.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/08/2017] [Accepted: 03/17/2017] [Indexed: 12/30/2022]
Abstract
BACKGROUND Diabetic retinopathy is a microvascular disease that results from retinal vascular degeneration and defective repair due to diabetes-induced endothelial progenitor dysfunction. OBJECTIVE Understanding key molecular factors involved in vascular degeneration and repair is paramount for developing effective diabetic retinopathy treatment strategies. We propose that diabetes-induced activation of acid sphingomyelinase (ASM) plays essential role in retinal endothelial and CD34+ circulating angiogenic cell (CAC) dysfunction in diabetes. METHODS Human retinal endothelial cells (HRECs) isolated from control and diabetic donor tissue and human CD34+ CACs from control and diabetic patients were used in this study. ASM messenger RNA and protein expression were assessed by quantitative polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. To evaluate the effect of diabetes-induced ASM on HRECs and CD34+ CACs function, tube formation, CAC incorporation into endothelial tubes, and diurnal release of CD34+ CACs in diabetic individuals were determined. RESULTS ASM expression level was significantly increased in HRECs isolated from diabetic compared with control donor tissue, as well as CD34+ CACs and plasma of diabetic patients. A significant decrease in tube area was observed in HRECs from diabetic donors compared with control HRECs. The tube formation deficiency was associated with increased expression of ASM in diabetic HRECs. Moreover, diabetic CD34+ CACs with high ASM showed defective incorporation into endothelial tubes. Diurnal release of CD34+ CACs was disrupted with the rhythmicity lost in diabetic patients. CONCLUSION Collectively, these findings support that diabetes-induced ASM upregulation has a marked detrimental effect on both retinal endothelial cells and CACs.
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Affiliation(s)
- Nermin Kady
- Department of Physiology, Michigan State University, East Lansing, MI, USA
| | - Yuanqing Yan
- Department of Biostatistics, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Tatiana Salazar
- Genetics and Genomics Graduate Program, Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL, USA
| | - Qi Wang
- Department of Physiology, Michigan State University, East Lansing, MI, USA
| | | | - Chao Huang
- Department of Physiology, Michigan State University, East Lansing, MI, USA
| | - Eleni Beli
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, USA
| | | | - Maria Grant
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, USA
| | - Julia Busik
- Department of Physiology, Michigan State University, East Lansing, MI, USA.
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Sharma S, Mathew AB, Chugh J. miRNAs: Nanomachines That Micromanage the Pathophysiology of Diabetes Mellitus. Adv Clin Chem 2017; 82:199-264. [PMID: 28939211 DOI: 10.1016/bs.acc.2017.06.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Diabetes mellitus (DM) refers to a combination of heterogeneous complex metabolic disorders that are associated with episodes of hyperglycemia and glucose intolerance occurring as a result of defects in insulin secretion, action, or both. The prevalence of DM is increasing at an alarming rate, and there exists a need to develop better therapeutics and prognostic markers for earlier detection and diagnosis. In this review, after giving a brief introduction of diabetes mellitus and microRNA (miRNA) biogenesis pathway, we first describe various in vitro and animal model systems that have been developed to study diabetes. Further, we elaborate on the significant roles played by miRNAs as regulators of gene expression in the context of development of diabetes and its secondary complications. The different approaches to quantify miRNAs and their potential to be used as therapeutic targets for alleviation of diabetes have also been discussed.
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Gu X, Reagan AM, McClellan ME, Elliott MH. Caveolins and caveolae in ocular physiology and pathophysiology. Prog Retin Eye Res 2016; 56:84-106. [PMID: 27664379 DOI: 10.1016/j.preteyeres.2016.09.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 09/15/2016] [Accepted: 09/20/2016] [Indexed: 12/14/2022]
Abstract
Caveolae are specialized, invaginated plasma membrane domains that are defined morphologically and by the expression of signature proteins called, caveolins. Caveolae and caveolins are abundant in a variety of cell types including vascular endothelium, glia, and fibroblasts where they play critical roles in transcellular transport, endocytosis, mechanotransduction, cell proliferation, membrane lipid homeostasis, and signal transduction. Given these critical cellular functions, it is surprising that ablation of the caveolae organelle does not result in lethality suggesting instead that caveolae and caveolins play modulatory roles in cellular homeostasis. Caveolar components are also expressed in ocular cell types including retinal vascular cells, Müller glia, retinal pigment epithelium (RPE), conventional aqueous humor outflow cells, the corneal epithelium and endothelium, and the lens epithelium. In the eye, studies of caveolae and other membrane microdomains (i.e., "lipid rafts") have lagged behind what is a substantial body of literature outside vision science. However, interest in caveolae and their molecular components has increased with accumulating evidence of important roles in vision-related functions such as blood-retinal barrier homeostasis, ocular inflammatory signaling, pathogen entry at the ocular surface, and aqueous humor drainage. The recent association of CAV1/2 gene loci with primary open angle glaucoma and intraocular pressure has further enhanced the need to better understand caveolar functions in the context of ocular physiology and disease. Herein, we provide the first comprehensive review of literature on caveolae, caveolins, and other membrane domains in the context of visual system function. This review highlights the importance of caveolae domains and their components in ocular physiology and pathophysiology and emphasizes the need to better understand these important modulators of cellular function.
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Affiliation(s)
- Xiaowu Gu
- Department of Ophthalmology/Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Alaina M Reagan
- Department of Ophthalmology/Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Mark E McClellan
- Department of Ophthalmology/Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Michael H Elliott
- Department of Ophthalmology/Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
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Dual Anti-Inflammatory and Anti-Angiogenic Action of miR-15a in Diabetic Retinopathy. EBioMedicine 2016; 11:138-150. [PMID: 27531575 PMCID: PMC5049929 DOI: 10.1016/j.ebiom.2016.08.013] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 07/26/2016] [Accepted: 08/06/2016] [Indexed: 11/22/2022] Open
Abstract
Activation of pro-inflammatory and pro-angiogenic pathways in the retina and the bone marrow contributes to pathogenesis of diabetic retinopathy. We identified miR-15a as key regulator of both pro-inflammatory and pro-angiogenic pathways through direct binding and inhibition of the central enzyme in the sphingolipid metabolism, ASM, and the pro-angiogenic growth factor, VEGF-A. miR-15a was downregulated in diabetic retina and bone marrow cells. Over-expression of miR-15a downregulated, and inhibition of miR-15a upregulated ASM and VEGF-A expression in retinal cells. In addition to retinal effects, migration and retinal vascular repair function was impaired in miR-15a inhibitor-treated circulating angiogenic cells (CAC). Diabetic mice overexpressing miR-15a under Tie-2 promoter had normalized retinal permeability compared to wild type littermates. Importantly, miR-15a overexpression led to modulation toward nondiabetic levels, rather than complete inhibition of ASM and VEGF-A providing therapeutic effect without detrimental consequences of ASM and VEGF-A deficiencies.
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