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Rajapakse D, Peterson K, Mishra S, Wistow G. Serum starvation of ARPE-19 changes the cellular distribution of cholesterol and Fibulin3 in patterns reminiscent of age-related macular degeneration. Exp Cell Res 2017; 361:333-341. [PMID: 29097185 PMCID: PMC5701823 DOI: 10.1016/j.yexcr.2017.10.036] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 10/25/2017] [Accepted: 10/28/2017] [Indexed: 11/29/2022]
Abstract
Retinal pigment epithelium (RPE) has been implicated as key source of cholesterol-rich deposits at Bruch's membrane (BrM) and in drusen in aging human eye. We have shown that serum-deprivation of confluent RPE cells is associated with upregulation of cholesterol synthesis and accumulation of unesterified cholesterol (UC). Here we investigate the cellular processes involved in this response. We compared the distribution and localization of UC and esterified cholesterol (EC); the age-related macular degeneration (AMD) associated EFEMP1/Fibulin3 (Fib3); and levels of acyl-coenzyme A (CoA): cholesterol acyltransferases (ACAT) ACAT1, ACAT2 and Apolipoprotein B (ApoB) in ARPE-19 cells cultured in serum-supplemented and serum-free media. The results were compared with distributions of these lipids and proteins in human donor eyes with AMD. Serum deprivation of ARPE-19 was associated with increased formation of FM dye-positive membrane vesicles, many of which co-labeled for UC. Additionally, UC colocalized with Fib3 in distinct granules. By day 5, serum-deprived cells grown on transwells secreted Fib3 basally into the matrix. While mRNA and protein levels of ACTA1 were constant over several days of serum-deprivation, ACAT2 levels increased significantly after serum-deprivation, suggesting increased formation of EC. The lower levels of intracellular EC observed under serum-deprivation were associated with increased formation and secretion of ApoB. The responses to serum-deprivation in RPE-derived cells: accumulation and secretion of lipids, lipoproteins, and Fib3 are very similar to patterns seen in human donor eyes with AMD and suggest that this model mimics processes relevant to disease progression.
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Affiliation(s)
- Dinusha Rajapakse
- Section on Molecular Structure and Functional Genomics, National Eye Institute, National Institutes of Health, Building 6 Room 106, Bethesda, MD, USA.
| | - Katherine Peterson
- Section on Molecular Structure and Functional Genomics, National Eye Institute, National Institutes of Health, Building 6 Room 106, Bethesda, MD, USA.
| | - Sanghamitra Mishra
- Section on Molecular Structure and Functional Genomics, National Eye Institute, National Institutes of Health, Building 6 Room 106, Bethesda, MD, USA.
| | - Graeme Wistow
- Section on Molecular Structure and Functional Genomics, National Eye Institute, National Institutes of Health, Building 6 Room 106, Bethesda, MD, USA.
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Rudolf M, Mir Mohi Sefat A, Miura Y, Tura A, Raasch W, Ranjbar M, Grisanti S, Aherrahrou Z, Wagner A, Messinger JD, Garber DW, Anantharamaiah GM, Curcio CA. ApoA-I Mimetic Peptide 4F Reduces Age-Related Lipid Deposition in Murine Bruch's Membrane and Causes Its Structural Remodeling. Curr Eye Res 2017; 43:135-146. [PMID: 28972410 DOI: 10.1080/02713683.2017.1370118] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
PURPOSE Accumulation of lipoprotein-derived lipids including esterified and unesterified cholesterol in Bruch's membrane of human eyes is a major age-related change involved in initiating and sustaining soft drusen in age-related macular degeneration (AMD). The apolipoprotein (apo) A-I mimetic peptide 4F is a small anti-inflammatory and anti-atherogenic agent, and potent modifier of plasma membranes. We evaluated the effect of intravitreally-injected 4F on murine Bruch's membrane. METHODS We tested single intravitreal injections of 4F doses (0.6 µg, 1.2 µg, 2.4 µg, and placebo scrambled peptide) in ApoEnull mice ≥10 months of age. After 30 days, mice were euthanized. Eyes were processed for either direct immunofluorescence detection of esterified cholesterol (EC) in Bruch's membrane whole mounts via a perfringolysin O-based marker linked to green fluorescent protein or by transmission electron microscopic visualization of Bruch's membrane integrity. Fluorescein isothiocyanate-conjugated 4F was traced after injection. RESULTS All injected eyes showed a dose-dependent reduction of Bruch's membrane EC with a concomitant ultrastructural improvement compared to placebo treated eyes. At a 2.4 µg dose of 4F, EC was reduced on average by ~60% and Bruch's membrane returned to a regular pentalaminar structure and thickness. Tracer studies confirmed that injected 4F reached intraocular targets. CONCLUSION We demonstrated a highly effective pharmacological reduction of EC and restoration of Bruch's membrane ultrastructure. The apoA-I mimetic peptide 4F is a novel way to treat a critical AMD disease process and thus represents a new candidate for treating the underlying cause of AMD.
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Affiliation(s)
- Martin Rudolf
- a Department of Ophthalmology , University of Lübeck , Lübeck , Germany
| | | | - Yoko Miura
- a Department of Ophthalmology , University of Lübeck , Lübeck , Germany
| | - Aysegül Tura
- a Department of Ophthalmology , University of Lübeck , Lübeck , Germany
| | - Walter Raasch
- b Department of Experimental and Clinical Pharmacology and Toxicology , University of Lübeck , Lübeck , Germany
| | - Mahdy Ranjbar
- a Department of Ophthalmology , University of Lübeck , Lübeck , Germany.,c Laboratory for Angiogenesis & Ocular Cell Transplantation , University of Lübeck , Lübeck , Germany
| | | | - Zouhair Aherrahrou
- d Institute of Integrative and Experimental Genomics , University of Lübeck , Lübeck , Germany
| | - Anna Wagner
- a Department of Ophthalmology , University of Lübeck , Lübeck , Germany
| | - Jeffrey D Messinger
- e Department of Ophthalmology , University of Alabama at Birmingham , Birmingham , AL , USA
| | - David W Garber
- f Atherosclerosis Research Unit , University of Alabama at Birmingham , Birmingham , AL , USA
| | - G M Anantharamaiah
- f Atherosclerosis Research Unit , University of Alabama at Birmingham , Birmingham , AL , USA.,g Department of Medicine, Biochemistry and Molecular Genetics , University of Alabama at Birmingham , Birmingham , AL , USA
| | - Christine A Curcio
- e Department of Ophthalmology , University of Alabama at Birmingham , Birmingham , AL , USA
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Storti F, Raphael G, Griesser V, Klee K, Drawnel F, Willburger C, Scholz R, Langmann T, von Eckardstein A, Fingerle J, Grimm C, Maugeais C. Regulated efflux of photoreceptor outer segment-derived cholesterol by human RPE cells. Exp Eye Res 2017; 165:65-77. [PMID: 28943268 DOI: 10.1016/j.exer.2017.09.008] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 09/18/2017] [Indexed: 12/19/2022]
Abstract
Genetic studies have linked age-related macular degeneration (AMD) to genes involved in high-density lipoprotein (HDL) metabolism, including ATP-binding cassette transporter A1 (ABCA1). The retinal pigment epithelium (RPE) handles large amounts of lipids, among others cholesterol, partially derived from internalized photoreceptor outer segments (OS) and lipids physiologically accumulate in the aging eye. To analyze the potential function of ABCA1 in the eye, we measured cholesterol efflux, the first step of HDL generation, in RPE cells. We show the expression of selected genes related to HDL metabolism in mouse and human eyecups as well as in ARPE-19 and human primary RPE cells. Immunofluorescence staining revealed localization of ABCA1 on both sides of polarized RPE cells. This was functionally confirmed by directional efflux to apolipoprotein AI (ApoA-I) of 3H-labeled cholesterol given to the cells via serum or via OS. ABCA1 expression and activity was modulated using a liver-X-receptor (LXR) agonist and an ABCA1 neutralizing antibody, demonstrating that the efflux was ABCA1-dependent. We concluded that the ABCA1-mediated lipid efflux pathway, and hence HDL biosynthesis, is functional in RPE cells towards both the basal (choroidal) and apical (subretinal) space. Impaired activity of the pathway might cause age-related perturbations of lipid homeostasis in the outer retina and thus may contribute to disease development and/or progression.
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Affiliation(s)
- Federica Storti
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland
| | - Gabriele Raphael
- Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Vera Griesser
- Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Katrin Klee
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland; Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Faye Drawnel
- Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Carolin Willburger
- Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Rebecca Scholz
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany
| | | | - Jürgen Fingerle
- Natural and Medical Sciences Institute, University of Tübingen, Tübingen, Germany
| | - Christian Grimm
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland; Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland; Neuroscience Center Zurich (ZNZ), University of Zurich, Zurich, Switzerland.
| | - Cyrille Maugeais
- Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
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Lakk M, Yarishkin O, Baumann JM, Iuso A, Križaj D. Cholesterol regulates polymodal sensory transduction in Müller glia. Glia 2017; 65:2038-2050. [PMID: 28856727 DOI: 10.1002/glia.23213] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 08/09/2017] [Accepted: 08/09/2017] [Indexed: 12/21/2022]
Abstract
Over- and underexposure to cholesterol activates glia in neurodegenerative brain and retinal diseases but the molecular targets of cholesterol in glial cells are not known. Here, we report that disruption of unesterified membrane cholesterol content modulates the transduction of chemical, mechanical and temperature stimuli in mouse Müller cells. Activation of TRPV4 (transient receptor potential vanilloid type 4), a nonselective polymodal cation channel was studied following the removal or supplementation of cholesterol using the methyl-beta cyclodextrin (MβCD) delivery vehicle. Cholesterol extraction disrupted lipid rafts and caveolae without affecting TRPV4 trafficking or membrane localization protein. However, MβCD suppressed agonist (GSK1016790A)- and temperature-evoked elevations in [Ca2+ ]i , and suppressed transcellular propagation of Ca2+ waves. Lowering the free membrane cholesterol content markedly prolonged the time-course of the glial swelling response, whereas MβCD:cholesterol supplementation enhanced agonist- and temperature-induced Ca2+ signals and shortened the swelling response. Taken together, these data show that membrane cholesterol modulates polymodal transduction of agonists, swelling and temperature stimuli in retinal radial glia and suggest that dyslipidemic retinas might be associated with abnormal glial transduction of ambient sensory inputs.
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Affiliation(s)
- Monika Lakk
- Departments of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah
| | - Oleg Yarishkin
- Departments of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah
| | | | - Anthony Iuso
- Departments of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah
| | - David Križaj
- Departments of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah
- Bioengineering, University of Utah, Salt Lake City, Utah
- Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah
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55
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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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56
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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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57
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Guziewicz KE, Sinha D, Gómez NM, Zorych K, Dutrow EV, Dhingra A, Mullins RF, Stone EM, Gamm DM, Boesze-Battaglia K, Aguirre GD. Bestrophinopathy: An RPE-photoreceptor interface disease. Prog Retin Eye Res 2017; 58:70-88. [PMID: 28111324 PMCID: PMC5441932 DOI: 10.1016/j.preteyeres.2017.01.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 01/16/2017] [Accepted: 01/18/2017] [Indexed: 11/17/2022]
Abstract
Bestrophinopathies, one of the most common forms of inherited macular degenerations, are caused by mutations in the BEST1 gene expressed in the retinal pigment epithelium (RPE). Both human and canine BEST1-linked maculopathies are characterized by abnormal accumulation of autofluorescent material within RPE cells and bilateral macular or multifocal lesions; however, the specific mechanism leading to the formation of these lesions remains unclear. We now provide an overview of the current state of knowledge on the molecular pathology of bestrophinopathies, and explore factors promoting formation of RPE-neuroretinal separations, using the first spontaneous animal model of BEST1-associated retinopathies, canine Best (cBest). Here, we characterize the nature of the autofluorescent RPE cell inclusions and report matching spectral signatures of RPE-associated fluorophores between human and canine retinae, indicating an analogous composition of endogenous RPE deposits in Best Vitelliform Macular Dystrophy (BVMD) patients and its canine disease model. This study also exposes a range of biochemical and structural abnormalities at the RPE-photoreceptor interface related to the impaired cone-associated microvillar ensheathment and compromised insoluble interphotoreceptor matrix (IPM), the major pathological culprits responsible for weakening of the RPE-neuroretina interactions, and consequently, formation of vitelliform lesions. These salient alterations detected at the RPE apical domain in cBest as well as in BVMD- and ARB-hiPSC-RPE model systems provide novel insights into the pathological mechanism of BEST1-linked disorders that will allow for development of critical outcome measures guiding therapeutic strategies for bestrophinopathies.
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Affiliation(s)
- Karina E Guziewicz
- Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, PA 19104, USA.
| | - Divya Sinha
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Néstor M Gómez
- Department of Anatomy & Cell Biology, School of Dental Medicine, University of Pennsylvania, PA 19104, USA
| | - Kathryn Zorych
- Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, PA 19104, USA
| | - Emily V Dutrow
- Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, PA 19104, USA
| | - Anuradha Dhingra
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, PA 19104, USA
| | - Robert F Mullins
- Department of Ophthalmology & Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Edwin M Stone
- Department of Ophthalmology & Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - David M Gamm
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Ophthalmology & Visual Sciences, University of Wisconsin-Madison, Madison, WI 53705, USA
| | | | - Gustavo D Aguirre
- Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, PA 19104, USA
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Zekavat SM, Lu J, Maugeais C, Mazer NA. An in silico model of retinal cholesterol dynamics (RCD model): insights into the pathophysiology of dry AMD. J Lipid Res 2017; 58:1325-1337. [PMID: 28442497 PMCID: PMC5496031 DOI: 10.1194/jlr.m074088] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 04/10/2017] [Indexed: 12/23/2022] Open
Abstract
We developed an in silico mathematical model of retinal cholesterol (Ch) dynamics (RCD) to quantify the physiological rate of Ch turnover in the rod outer segment (ROS), the lipoprotein transport mechanisms by which Ch enters and leaves the outer retina, and the rates of drusen growth and macrophage-mediated clearance in dry age-related macular degeneration. Based on existing experimental data and mechanistic hypotheses, we estimated the Ch turnover rate in the ROS to be 1–6 pg/mm2/min, dependent on the rate of Ch recycling in the outer retina, and found comparable rates for LDL receptor-mediated endocytosis of Ch by the retinal pigment epithelium (RPE), ABCA1-mediated Ch transport from the RPE to the outer retina, ABCA1-mediated Ch efflux from the RPE to the choroid, and the secretion of 70 nm ApoB-Ch particles from the RPE. The drusen growth rate is predicted to increase from 0.7 to 4.2 μm/year in proportion to the flux of ApoB-Ch particles. The rapid regression of drusen may be explained by macrophage-mediated clearance if the macrophage density reaches ∼3,500 cells/mm2. The RCD model quantifies retinal Ch dynamics and suggests that retinal Ch turnover and recycling, ApoB-Ch particle efflux, and macrophage-mediated clearance may explain the dynamics of drusen growth and regression.
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Affiliation(s)
| | - James Lu
- Departments of Clinical Pharmacology and Neuroscience, Ophthalmology, and
| | - Cyrille Maugeais
- Rare Diseases, Roche Innovation Center Basel, Basel, Switzerland
| | - Norman A Mazer
- Departments of Clinical Pharmacology and Neuroscience, Ophthalmology, and.
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Dai B, Lei C, Lin R, Tao L, Bin Y, Peng H, Lei B. Activation of liver X receptor α protects amyloid β 1-40 induced inflammatory and senescent responses in human retinal pigment epithelial cells. Inflamm Res 2017; 66:523-534. [PMID: 28361293 DOI: 10.1007/s00011-017-1036-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 03/09/2017] [Accepted: 03/13/2017] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVE To investigate whether activation of the liver X receptors (LXRs) inhibits amyloid β1-40 (Aβ1-40) induced inflammatory and senescent responses in human retinal pigment epithelial (RPE) cells. MATERIALS AND METHODS Confluent cultures of human primary RPE and ARPE-19 cells pretreated with 5 μΜ of TO901317 (TO90), a synthetic agonist of LXR, or vehicle were incubated with 1 μΜ of Aβ1-40 or Aβ40-1. The optimum concentrations of Aβ1-40 and TO90 were determined by cell viability assay. Pro-inflammatory cytokines IL-6, IL-8, MCP-1 were detected by real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA). Expression and localization of an aging protein p16INK4a (p16) were analyzed by western blotting and immunofluorescence. Expressions of LXRs and one of their target genes ATP-binding cassette transporter A1 (ABCA1) were examined by real-time PCR and western blotting. Phosphorylated transcription inhibition factor-κB-α (p-IκB-α) was assessed by western blotting. RESULTS A negative linear relationship between the Aβ1-40 concentration and the cell viability was evident, indicating Aβ1-40 decreased ARPE-19 cell viability in a dose-dependent manner. Aβ1-40 enhanced the expression of IL-6, IL-8, MCP-1 as well as p16 in both RPE cell lines at both mRNA and protein levels, whereas TO90 counteracted the detrimental effects. TO90 upregulated the expression of LXRα and its target gene ABCA1, but it did not affect the expression of LXRβ. Meanwhile, TO90 inhibited the phosphorylation of IκB-α mediated by Aβ1-40 stimulation. CONCLUSION Activation of the LXRα-ABCA1 axis may alleviate Aβ1-40 induced inflammatory and senescent responses in RPE cells. The beneficial effect appears associated with the inhibition of the NF-κB signaling pathway.
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Affiliation(s)
- Bingling Dai
- Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Chongqing, 400016, China
| | - Chunyan Lei
- Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Chongqing, 400016, China
| | - Ru Lin
- Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Chongqing, 400016, China
| | - Lifei Tao
- Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Chongqing, 400016, China
| | - Yue Bin
- Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Chongqing, 400016, China
| | - Hui Peng
- Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Chongqing, 400016, China.
| | - Bo Lei
- Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Chongqing, 400016, China.
- Henan Provincial People's Hospital, Henan Eye Institute, Henan Eye Hospital, People's Hospital of Zhengzhou University, 7 Weiwu Road, Zhengzhou, 450003, China.
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Potential protective function of the sterol regulatory element binding factor 1-fatty acid desaturase 1/2 axis in early-stage age-related macular degeneration. Heliyon 2017; 3:e00266. [PMID: 28367511 PMCID: PMC5362043 DOI: 10.1016/j.heliyon.2017.e00266] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 03/06/2017] [Accepted: 03/09/2017] [Indexed: 12/12/2022] Open
Abstract
Age-related macular degeneration (AMD) is the most common cause of vision loss in elderly individuals throughout the developed world. Inhibitors of vascular endothelial growth factor have been successfully used to treat choroidal neovascularization in late-stage AMD. The pathogenesis of early-stage AMD, however, remains largely unknown, impairing efforts to develop effective therapies that prevent progression to late-stage AMD. To address this, we performed comparative transcriptomics of macular and extramacular retinal pigmented epithelium-choroid (RPE-choroid) tissue from early-stage AMD patients. We found that expression of fatty acid desaturase 1 (FADS1), FADS2, and acetyl-CoA acetyltransferase 2 (ACAT2) is increased in macular but not extramacular tissue, possibly through activation of sterol regulatory element binding factor 1 (SREBF1). Consistent with this, we also found that expression of Fads1 is increased in RPE-choroid in a mouse model of early-stage AMD. In zebrafish, deletion of fads2, which encodes a protein that functions as both Fads1 and Fads2 in other species, enhanced apoptosis in the retina upon exposure to intense light. Similarly, pharmacological inhibition of Srebf1 enhanced apoptosis and reduced fads2 expression in zebrafish exposed to intense light. These results suggest that the SREBF1-FADS1/2 axis may be activated in macular RPE-choroid as a protective response during early-stage AMD and could thus be a therapeutic target for early-stage AMD.
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61
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24(S)-Hydroxycholesterol protects the ex vivo rat retina from injury by elevated hydrostatic pressure. Sci Rep 2016; 6:33886. [PMID: 27653972 PMCID: PMC5032171 DOI: 10.1038/srep33886] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 09/05/2016] [Indexed: 01/01/2023] Open
Abstract
In the central nervous system, 24(S)-hydroxycholesterol (24(S)-HC) is an oxysterol synthesized from cholesterol by cholesterol 24-hydroxylase (CYP46A1) encoded by the cyp46a1 gene. In the present study using a rat ex vivo glaucoma model, we found that retinal 24(S)-HC synthesis is facilitated by pressure elevation. Moreover, we found that 24(S)-HC is neuroprotective against pressure mediated retinal degeneration. Quantitative real-time RT-PCR, ELISA, and immunohistochemistry revealed that elevated pressure facilitated the expression of cyp46a1 and CYP46A1. Immunohistochemically, the enhanced expression of CYP46A1 was mainly observed in retinal ganglion cells (RGC). LC-MS/MS revealed that 24(S)-HC levels increased in a pressure-dependent manner. Axonal injury and apoptotic RGC death induced by 75 mmHg high pressure was ameliorated by exogenously administered 1 μM 24(S)-HC. In contrast, voriconazole, a CYP46A1 inhibitor, was severely toxic even at normobaric pressure. Under normobaric conditions, 30 μM 24(S)-HC was required to prevent the voriconazole-mediated retinal damage. Taken together, our findings indicate that 24(S)-HC is facilitated by elevated pressure and plays a neuroprotective role under glaucomatous conditions, while voriconazole, an antifungal drug, is retinotoxic. 24(S)-HC and related compounds may serve as potential therapeutic targets for protecting glaucomatous eyes from pressure-induced injuries.
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Saadane A, Mast N, Dao T, Ahmad B, Pikuleva IA. Retinal Hypercholesterolemia Triggers Cholesterol Accumulation and Esterification in Photoreceptor Cells. J Biol Chem 2016; 291:20427-39. [PMID: 27514747 DOI: 10.1074/jbc.m116.744656] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Indexed: 01/01/2023] Open
Abstract
The process of vision is impossible without the photoreceptor cells, which have a unique structure and specific maintenance of cholesterol. Herein we report on the previously unrecognized cholesterol-related pathway in the retina discovered during follow-up characterizations of Cyp27a1(-/-)Cyp46a1(-/-) mice. These animals have retinal hypercholesterolemia and convert excess retinal cholesterol into cholesterol esters, normally present in the retina in very small amounts. We established that in the Cyp27a1(-/-)Cyp46a1(-/-) retina, cholesterol esters are generated by and accumulate in the photoreceptor outer segments (OS), which is the retinal layer with the lowest cholesterol content. Mouse OS were also found to express the cholesterol-esterifying enzyme acyl-coenzyme A:cholesterol acyltransferase (ACAT1), but not lecithin-cholesterol acyltransferase (LCAT), and to differ from humans in retinal expression of ACAT1. Nevertheless, cholesterol esters were discovered to be abundant in human OS. We suggest a mechanism for cholesterol ester accumulation in the OS and that activity impairment of ACAT1 in humans may underlie the development of subretinal drusenoid deposits, a hallmark of age-related macular degeneration, which is a common blinding disease. We generated Cyp27a1(-/-)Cyp46a1(-/-)Acat1(-/-) mice, characterized their retina by different imaging modalities, and confirmed that unesterified cholesterol does accumulate in their OS and that there is photoreceptor apoptosis and OS degeneration in this line. Our results provide insights into the retinal response to local hypercholesterolemia and the retinal significance of cholesterol esterification, which could be cell-specific and both beneficial and detrimental for retinal structure and function.
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Affiliation(s)
- Aicha Saadane
- From the Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio and
| | - Natalia Mast
- From the Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio and
| | - Tung Dao
- From the Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio and
| | - Baseer Ahmad
- From the Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio and the University Hospitals, Cleveland, Ohio 44106
| | - Irina A Pikuleva
- From the Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio and
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63
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Sarzi E, Seveno M, Angebault C, Milea D, Rönnbäck C, Quilès M, Adrian M, Grenier J, Caignard A, Lacroux A, Lavergne C, Reynier P, Larsen M, Hamel CP, Delettre C, Lenaers G, Müller A. Increased steroidogenesis promotes early-onset and severe vision loss in females with OPA1 dominant optic atrophy. Hum Mol Genet 2016; 25:2539-2551. [PMID: 27260406 DOI: 10.1093/hmg/ddw117] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 03/26/2016] [Accepted: 04/12/2016] [Indexed: 11/13/2022] Open
Abstract
OPA1 mutations are responsible for autosomal dominant optic atrophy (ADOA), a progressive blinding disease characterized by retinal ganglion cell (RGC) degeneration and large phenotypic variations, the underlying mechanisms of which are poorly understood. OPA1 encodes a mitochondrial protein with essential biological functions, its main roles residing in the control of mitochondrial membrane dynamics as a pro-fusion protein and prevention of apoptosis. Considering recent findings showing the importance of the mitochondrial fusion process and the involvement of OPA1 in controlling steroidogenesis, we tested the hypothesis of deregulated steroid production in retina due to a disease-causing OPA1 mutation and its contribution to the visual phenotypic variations. Using the mouse model carrying the human recurrent OPA1 mutation, we disclosed that Opa1 haploinsufficiency leads to very high circulating levels of steroid precursor pregnenolone in females, causing an early-onset vision loss, abolished by ovariectomy. In addition, steroid production in retina is also increased which, in conjunction with high circulating levels, impairs estrogen receptor expression and mitochondrial respiratory complex IV activity, promoting RGC apoptosis in females. We further demonstrate the involvement of Muller glial cells as increased pregnenolone production in female cells is noxious and compromises their role in supporting RGC survival. In parallel, we analyzed ophthalmological data of a multicentre OPA1 patient cohort and found that women undergo more severe visual loss at adolescence and greater progressive thinning of the retinal nerve fibres than males. Thus, we disclosed a gender-dependent effect on ADOA severity, involving for the first time steroids and Müller glial cells, responsible for RGC degeneration.
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Affiliation(s)
- Emmanuelle Sarzi
- INSERM U1051 - Institut des Neurosciences de Montpellier, Montpellier, France,
| | - Marie Seveno
- INSERM U1051 - Institut des Neurosciences de Montpellier, Montpellier, France
| | - Claire Angebault
- INSERM U1051 - Institut des Neurosciences de Montpellier, Montpellier, France
| | - Dan Milea
- Département de Biochimie et Génétique, UMR CNRS 6214-INSERM 1083, Centre Hospitalier Universitaire, Angers, France.,Singapore National Eye Centre, Singapore.,Singapore Eye Research Institute, Singapore.,Duke-NUS, Singapore
| | - Cecilia Rönnbäck
- Department of Ophthalmology, Glostrup Hospital, Glostrup, Denmark.,Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Melanie Quilès
- INSERM U1051 - Institut des Neurosciences de Montpellier, Montpellier, France.,Université de Montpellier - Faculté de Pharmacie-Montpellier, France
| | - Mathias Adrian
- INSERM U1051 - Institut des Neurosciences de Montpellier, Montpellier, France
| | - Joanna Grenier
- INSERM U1051 - Institut des Neurosciences de Montpellier, Montpellier, France.,Centre de référence des affections sensorielles d'origine génétique, Hôpital Gui de Chauliac, Montpellier, France
| | - Angélique Caignard
- Département de Biochimie et Génétique, UMR CNRS 6214-INSERM 1083, Centre Hospitalier Universitaire, Angers, France
| | - Annie Lacroux
- INSERM U1051 - Institut des Neurosciences de Montpellier, Montpellier, France.,Centre de référence des affections sensorielles d'origine génétique, Hôpital Gui de Chauliac, Montpellier, France
| | - Christian Lavergne
- Institut Montpelliérain Alexander Grothendieck. Université Montpellier 3, France and
| | - Pascal Reynier
- Département de Biochimie et Génétique, UMR CNRS 6214-INSERM 1083, Centre Hospitalier Universitaire, Angers, France
| | - Michael Larsen
- Department of Ophthalmology, Glostrup Hospital, Glostrup, Denmark.,Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Christian P Hamel
- INSERM U1051 - Institut des Neurosciences de Montpellier, Montpellier, France.,Centre de référence des affections sensorielles d'origine génétique, Hôpital Gui de Chauliac, Montpellier, France
| | - Cécile Delettre
- INSERM U1051 - Institut des Neurosciences de Montpellier, Montpellier, France,
| | - Guy Lenaers
- INSERM U1051 - Institut des Neurosciences de Montpellier, Montpellier, France.,PREMMI, UMR CNRS 6214-INSERM 1083, Université d'Angers, France
| | - Agnès Müller
- INSERM U1051 - Institut des Neurosciences de Montpellier, Montpellier, France.,Université de Montpellier - Faculté de Pharmacie-Montpellier, France
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64
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Fernández-Navarro J, Aldea P, de Hoz R, Salazar JJ, Ramírez AI, Rojas B, Gallego BI, Triviño A, Tejerina T, Ramírez JM. Neuroprotective Effects of Low-Dose Statins in the Retinal Ultrastructure of Hypercholesterolemic Rabbits. PLoS One 2016; 11:e0154800. [PMID: 27144842 PMCID: PMC4856380 DOI: 10.1371/journal.pone.0154800] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 04/19/2016] [Indexed: 11/19/2022] Open
Abstract
To evaluate the pleiotropic effects to statins, we analyze the qualitative and quantitative retinal changes in hypercholesterolemic rabbits after a low-dosage statin treatment. For this purpose, New Zealand rabbits were split into three groups: control (G0; n = 10), fed a standard diet; hypercholesterolemic (G1; n = 8), fed a 0.5% cholesterol-enriched diet for 8 months; and statins (G2; n = 8), fed a 0.5% cholesterol-enriched diet for 8 months, together with the administration of statin (pravastatin or fluvastatin sodium) at a dose of 2 mg / kg / day each diet. The retinas were analyzed by transmission electron microscopy and immunohistochemistry (glial fibrillary acidic protein). The retinal thickness of nuclear and plexiform layers were quantified in semi-thin sections. The results revealed that the low-statin-treated rabbits in comparison with the hypercholesterolemic group showed: i) a more preserved structure in all retinal layers; ii) a significant reduction in retinal thickness; iii) a decrease in cell death in the nuclear-and ganglion-cell layers; iv) a reduction of hydropic degeneration in the plexiform and nerve-fiber layers; v) a preservation of astrocytes and of the retinal area occupied by them; and vi) a better-preserved retinal vascular structure. Our findings indicate that low doses of statins can prevent retinal degeneration, acting on retinal macroglia, neurons and retinal vessels, despite that hypercholesterolemia remained unchanged. Thus, the pleiotropic effects of the statins may help safeguard the retinal ultrastructure.
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Affiliation(s)
- Judith Fernández-Navarro
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo. Universidad Complutense Madrid (UCM), Spain
| | - Pilar Aldea
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo. Universidad Complutense Madrid (UCM), Spain
| | - Rosa de Hoz
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo. Universidad Complutense Madrid (UCM), Spain
- Facultad de Óptica y Optometría, UCM, Spain
| | - Juan J Salazar
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo. Universidad Complutense Madrid (UCM), Spain
- Facultad de Óptica y Optometría, UCM, Spain
| | - Ana I Ramírez
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo. Universidad Complutense Madrid (UCM), Spain
- Facultad de Óptica y Optometría, UCM, Spain
| | - Blanca Rojas
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo. Universidad Complutense Madrid (UCM), Spain
- Facultad de Medicina, UCM, Spain
| | - Beatriz I. Gallego
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo. Universidad Complutense Madrid (UCM), Spain
- Facultad de Óptica y Optometría, UCM, Spain
| | - Alberto Triviño
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo. Universidad Complutense Madrid (UCM), Spain
- Facultad de Medicina, UCM, Spain
| | - Teresa Tejerina
- Department of Pharmacology, School of Medicine, Complutense University, Madrid, Spain
| | - José M. Ramírez
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo. Universidad Complutense Madrid (UCM), Spain
- Facultad de Medicina, UCM, Spain
- * E-mail:
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65
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Yao J, Jia L, Khan N, Lin C, Mitter SK, Boulton ME, Dunaief JL, Klionsky DJ, Guan JL, Thompson DA, Zacks DN. Deletion of autophagy inducer RB1CC1 results in degeneration of the retinal pigment epithelium. Autophagy 2016; 11:939-53. [PMID: 26075877 DOI: 10.1080/15548627.2015.1041699] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Autophagy regulates cellular homeostasis and response to environmental stress. Within the retinal pigment epithelium (RPE) of the eye, the level of autophagy can change with both age and disease. The purpose of this study is to determine the relationship between reduced autophagy and age-related degeneration of the RPE. The gene encoding RB1CC1/FIP200 (RB1-inducible coiled-coil 1), a protein essential for induction of autophagy, was selectively knocked out in the RPE by crossing Best1-Cre mice with mice in which the Rb1cc1 gene was flanked with Lox-P sites (Rb1cc1(flox/flox)). Ex vivo and in vivo analyses, including western blot, immunohistochemistry, transmission electron microscopy, fundus photography, optical coherence tomography, fluorescein angiography, and electroretinography were performed to assess the structure and function of the retina as a function of age. Deletion of Rb1cc1 resulted in multiple autophagy defects within the RPE including decreased conversion of LC3-I to LC3-II, accumulation of autophagy-targeted precursors, and increased numbers of mitochondria. Age-dependent degeneration of the RPE occurred, with formation of atrophic patches, subretinal migration of activated microglial cells, subRPE deposition of inflammatory and oxidatively damaged proteins, subretinal drusenoid deposits, and occasional foci of choroidal neovascularization. There was secondary loss of photoreceptors overlying the degenerated RPE and reduction in the electroretinogram. These observations are consistent with a critical role of autophagy in the maintenance of normal homeostasis in the aging RPE, and indicate that disruption of autophagy leads to retinal phenotypes associated with age-related degeneration.
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Key Words
- AMD, age-related macular degeneration
- ANOVA, analysis of variance
- Bru, Bruch's membrane
- CKO, conditional knockout
- CTSD, cathepsin D
- ERG, electroretinogram
- FIP200
- GCL, ganglion cell layer
- INL, inner nuclear layer
- IS, inner segment
- LAP, LC3-associated phagocytosis
- MTOR, mechanistic target of rapamycin
- OCT, optical coherence tomography
- ONL, outer nuclear layer
- OS, outer segment
- PBS, phosphate-buffered saline
- POS, photoreceptor outer segments
- RB1CC1, RB1-inducible coiled-coil 1
- RPE, retinal pigment epithelium
- age-related macular degeneration
- photoreceptor
- retina
- retinal pigment epithelium
- siRNA, small interfering ribonucleic acid.
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Affiliation(s)
- Jingyu Yao
- a Department of Ophthalmology and Visual Sciences ; University of Michigan ; Ann Arbor , MI USA
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66
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Abstract
The cholesterol transporting protein apolipoprotein E (ApoE) occurs in three allelic variants in humans unlike in other species. The resulting protein isoforms E2, E3 and E4 exhibit differences in lipid binding, integrating into lipoprotein particles and affinity for lipoprotein receptors. ApoE isoforms confer genetic risk for several diseases of aging including atherosclerosis, Alzheimer's disease, and age-related macular degeneration (AMD). A single E4 allele increases the risk of developing Alzheimer's disease, whereas the E2 allele is protective. Intriguingly, the E4 allele is protective in AMD. Current thinking about different functions of ApoE isoforms comes largely from studies on Alzheimer's disease. These data cannot be directly extrapolated to AMD since the primary cells affected in these diseases (neurons vs. retinal pigment epithelium) are so different. Here, we propose that ApoE serves a fundamentally different purpose in regulating cholesterol homeostasis in the retinal pigment epithelium and this could explain why allelic risk factors are flipped for AMD compared to Alzheimer's disease.
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67
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Quantification of histone deacetylase isoforms in human frontal cortex, human retina, and mouse brain. PLoS One 2015; 10:e0126592. [PMID: 25962138 PMCID: PMC4427357 DOI: 10.1371/journal.pone.0126592] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 04/06/2015] [Indexed: 12/30/2022] Open
Abstract
Histone deacetylase (HDAC) inhibition has promise as a therapy for Alzheimer’s disease (AD) and other neurodegenerative diseases. Currently, therapeutic HDAC inhibitors target many HDAC isoforms, a particularly detrimental approach when HDAC isoforms are known to have different and specialized functions. We have developed a multiple reaction monitoring (MRM) mass spectrometry assay using stable isotope-labeled QconCATs as internal standards to quantify HDAC isoforms. We further determined a quantitative pattern of specific HDACs expressed in various human and mouse neural tissues. In human AD frontal cortex, HDAC1,2 decreased 32%, HDAC5 increased 47%, and HDAC6 increased 31% in comparison to age-matched controls. Human neural retina concentrations of HDAC1, 2, HDAC5, HDAC6, and HDAC7 decreased in age-related macular degeneration (AMD)-affected donors and exhibited a greater decrease in AD-affected donors in comparison to age-matched control neural retinas. Additionally, HDAC concentrations were measured in whole hemisphere of brain of 5XFAD mice, a model of β-amyloid deposition, to assess similarity to AD in human frontal cortex. HDAC profiles of human frontal cortex and mouse hemisphere had noticeable differences and relatively high concentrations of HDAC3 and HDAC4 in mice, which were undetectable in humans. Our method for quantification of HDAC isoforms is a practical and efficient technique to quantify isoforms in various tissues and diseases. Changes in HDAC concentrations reported herein contribute to the understanding of the pathology of neurodegeneration.
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68
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Affiliation(s)
- Steven J Fliesler
- Departments of Ophthalmology and Biochemistry, University at Buffalo-The State University of New York (SUNY); the SUNY Eye Institute; and the Research Service, Veterans Administration Western New York Healthcare System (VAWNYHS), Buffalo, NY 14215
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69
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Song Q, Zhao C, Ou S, Meng Z, Kang P, Fan L, Qi F, Ma Y. Co-expression analysis of differentially expressed genes in hepatitis C virus-induced hepatocellular carcinoma. Mol Med Rep 2014; 11:21-8. [PMID: 25339452 PMCID: PMC4237098 DOI: 10.3892/mmr.2014.2695] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 03/21/2014] [Indexed: 12/11/2022] Open
Abstract
The aim of the current study was to investigate the molecular mechanisms underlying hepatitis C virus (HCV)-induced hepatocellular carcinoma (HCC) using the expression profiles of HCV-infected Huh7 cells at different time points. The differentially expressed genes (DEGs) were identified with the Samr package in R software once the data were normalized. Functional and pathway enrichment analysis of the identified DEGs was also performed. Subsequently, MCODE in Cytoscape software was applied to conduct module analysis of the constructed co-expression networks. A total of 1,100 DEGs were identified between the HCV-infected and control samples at 12, 18, 24 and 48 h post-infection. DEGs at 24 and 48 h were involved in the same signaling pathways and biological processes, including sterol biosynthetic processes and tRNA amino-acylation. There were 22 time series genes which were clustered into 3 expression patterns, and the demarcation point of the 2 expression patterns that 401 overlapping DEGs at 24 and 48 h clustered into was 24 h post-infection. tRNA synthesis-related biological processes emerged at 24 and 48 h. Replication and assembly of HCV in HCV-infected Huh7 cells occurred mainly at 24 h post-infection. In view of this, the screened time series genes have the potential to become candidate target molecules for monitoring, diagnosing and treating HCV-induced HCC.
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Affiliation(s)
- Qingfeng Song
- Department of Interventional Radiology, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
| | - Chang Zhao
- Department of Interventional Radiology, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
| | - Shengqiu Ou
- Department of Interventional Radiology, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
| | - Zhibin Meng
- Department of Interventional Radiology, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
| | - Ping Kang
- Department of Interventional Radiology, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
| | - Liwei Fan
- Department of Interventional Radiology, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
| | - Feng Qi
- Department of Interventional Radiology, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
| | - Yilong Ma
- Department of Interventional Radiology, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
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70
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Zheng W, Mast N, Saadane A, Pikuleva IA. Pathways of cholesterol homeostasis in mouse retina responsive to dietary and pharmacologic treatments. J Lipid Res 2014; 56:81-97. [PMID: 25293590 DOI: 10.1194/jlr.m053439] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Effects of serum cholesterol on cholesterol content in the retina are currently unknown. It is also unclear how cholesterol levels are controlled in the retina. High-cholesterol diet and oral administrations of simvastatin were used to modulate serum cholesterol in mice. These treatments only modestly affected cholesterol content in the retina and had no significant effect on retinal expression of the major cholesterol- and vision-related genes; the sterol-regulatory element binding protein pathway of transcriptional regulation does not seem to be operative in the retina under the experimental conditions used. Evidence is obtained that posttranslational mechanisms play a role in the control of retinal cholesterol. Retinal genes were only upregulated by oral administrations of TO901317 activating liver X receptors. Three of the upregulated genes could be of particular importance (apoD, Idol, and Rpe65) and have not yet been considered in the context of cholesterol homeostasis in the retina. Collectively, the data obtained identify specific features of retinal cholesterol maintenance and suggest additional therapies for age-related macular degeneration, a blinding disease characterized by cholesterol and lipid accumulations in chorioretinal tissues.
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Affiliation(s)
- Wenchao Zheng
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106
| | - Natalia Mast
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106
| | - Aicha Saadane
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106
| | - Irina A Pikuleva
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106
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71
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Malek G, Lad EM. Emerging roles for nuclear receptors in the pathogenesis of age-related macular degeneration. Cell Mol Life Sci 2014; 71:4617-36. [PMID: 25156067 DOI: 10.1007/s00018-014-1709-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 08/14/2014] [Accepted: 08/18/2014] [Indexed: 12/20/2022]
Abstract
Age-related macular degeneration (AMD) is the leading cause of vision loss in the elderly in the Western world. Over the last 30 years, our understanding of the pathogenesis of the disease has grown exponentially thanks to the results of countless epidemiology, genetic, histological, and biochemical studies. This information, in turn, has led to the identification of multiple biologic pathways potentially involved in development and progression of AMD, including but not limited to inflammation, lipid and extracellular matrix dysregulation, and angiogenesis. Nuclear receptors are a superfamily of transcription factors that have been shown to regulate many of the pathogenic pathways linked with AMD and as such they are emerging as promising targets for therapeutic intervention. In this review, we will present the fundamental phenotypic features of AMD and discuss our current understanding of the pathobiological disease mechanisms. We will introduce the nuclear receptor superfamily and discuss the current literature on their effects on AMD-related pathophysiology.
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Affiliation(s)
- Goldis Malek
- Department of Ophthalmology, Duke University School of Medicine, 2351 Erwin Road, AERI Room 4006, Durham, NC, 27710, USA,
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72
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Saadane A, Mast N, Charvet CD, Omarova S, Zheng W, Huang SS, Kern TS, Peachey NS, Pikuleva IA. Retinal and nonocular abnormalities in Cyp27a1(-/-)Cyp46a1(-/-) mice with dysfunctional metabolism of cholesterol. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:2403-19. [PMID: 25065682 DOI: 10.1016/j.ajpath.2014.05.024] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 05/21/2014] [Accepted: 05/29/2014] [Indexed: 01/08/2023]
Abstract
Cholesterol elimination from nonhepatic cells involves metabolism to side-chain oxysterols, which serve as transport forms of cholesterol and bioactive molecules modulating a variety of cellular processes. Cholesterol metabolism is tissue specific, and its significance has not yet been established for the retina, where cytochromes P450 (CYP27A1 and CYP46A1) are the major cholesterol-metabolizing enzymes. We generated Cyp27a1(-/-)Cyp46a1(-/-) mice, which were lean and had normal serum cholesterol and glucose levels. These animals, however, had changes in the retinal vasculature, retina, and several nonocular organs (lungs, liver, and spleen). Changes in the retinal vasculature included structural abnormalities (retinal-choroidal anastomoses, arteriovenous shunts, increased permeability, dilation, nonperfusion, and capillary degeneration) and cholesterol deposition and oxidation in the vascular wall, which also exhibited increased adhesion of leukocytes and activation of the complement pathway. Changes in the retina included increased content of cholesterol and its metabolite, cholestanol, which were focally deposited at the apical and basal sides of the retinal pigment epithelium. Retinal macrophages of Cyp27a1(-/-)Cyp46a1(-/-) mice were activated, and oxidative stress was noted in their photoreceptor inner segments. Our findings demonstrate the importance of retinal cholesterol metabolism for maintenance of the normal retina, and suggest new targets for diseases affecting the retinal vasculature.
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Affiliation(s)
- Aicha Saadane
- Department of Ophthalmology and Visual Sciences, Cleveland, Ohio
| | - Natalia Mast
- Department of Ophthalmology and Visual Sciences, Cleveland, Ohio
| | - Casey D Charvet
- Department of Ophthalmology and Visual Sciences, Cleveland, Ohio
| | - Saida Omarova
- Department of Ophthalmology and Visual Sciences, Cleveland, Ohio
| | - Wenchao Zheng
- Department of Ophthalmology and Visual Sciences, Cleveland, Ohio
| | - Suber S Huang
- Department of Ophthalmology and Visual Sciences, Cleveland, Ohio; Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Timothy S Kern
- Department of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Neal S Peachey
- Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio; Cleveland VA Medical Center, Cleveland, Ohio; Department of Medicine, University Hospitals, Cleveland, Ohio
| | - Irina A Pikuleva
- Department of Ophthalmology and Visual Sciences, Cleveland, Ohio.
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73
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Koo E, Neuringer M, SanGiovanni JP. Macular xanthophylls, lipoprotein-related genes, and age-related macular degeneration. Am J Clin Nutr 2014; 100 Suppl 1:336S-46S. [PMID: 24829491 PMCID: PMC4144106 DOI: 10.3945/ajcn.113.071563] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Plant-based macular xanthophylls (MXs; lutein and zeaxanthin) and the lutein metabolite meso-zeaxanthin are the major constituents of macular pigment, a compound concentrated in retinal areas that are responsible for fine-feature visual sensation. There is an unmet need to examine the genetics of factors influencing regulatory mechanisms and metabolic fates of these 3 MXs because they are linked to processes implicated in the pathogenesis of age-related macular degeneration (AMD). In this work we provide an overview of evidence supporting a molecular basis for AMD-MX associations as they may relate to DNA sequence variation in AMD- and lipoprotein-related genes. We recognize a number of emerging research opportunities, barriers, knowledge gaps, and tools offering promise for meaningful investigation and inference in the field. Overviews on AMD- and high-density lipoprotein (HDL)-related genes encoding receptors, transporters, and enzymes affecting or affected by MXs are followed with information on localization of products from these genes to retinal cell types manifesting AMD-related pathophysiology. Evidence on the relation of each gene or gene product with retinal MX response to nutrient intake is discussed. This information is followed by a review of results from mechanistic studies testing gene-disease relations. We then present findings on relations of AMD with DNA sequence variants in MX-associated genes. Our conclusion is that AMD-associated DNA variants that influence the actions and metabolic fates of HDL system constituents should be examined further for concomitant influence on MX absorption, retinal tissue responses to MX intake, and the capacity to modify MX-associated factors and processes implicated in AMD pathogenesis.
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Affiliation(s)
- Euna Koo
- From the Department of Ophthalmology, University of California at San Francisco, San Francisco, CA (EK); the Oregon National Primate Research Center and Casey Eye Institute, Oregon Health Sciences University, Portland, OR (MN); and the National Eye Institute, National Institutes of Health, Bethesda, MD (JPS)
| | - Martha Neuringer
- From the Department of Ophthalmology, University of California at San Francisco, San Francisco, CA (EK); the Oregon National Primate Research Center and Casey Eye Institute, Oregon Health Sciences University, Portland, OR (MN); and the National Eye Institute, National Institutes of Health, Bethesda, MD (JPS)
| | - John Paul SanGiovanni
- From the Department of Ophthalmology, University of California at San Francisco, San Francisco, CA (EK); the Oregon National Primate Research Center and Casey Eye Institute, Oregon Health Sciences University, Portland, OR (MN); and the National Eye Institute, National Institutes of Health, Bethesda, MD (JPS)
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Ratnapriya R, Zhan X, Fariss RN, Branham KE, Zipprer D, Chakarova CF, Sergeev YV, Campos MM, Othman M, Friedman JS, Maminishkis A, Waseem NH, Brooks M, Rajasimha HK, Edwards AO, Lotery A, Klein BE, Truitt BJ, Li B, Schaumberg DA, Morgan DJ, Morrison MA, Souied E, Tsironi EE, Grassmann F, Fishman GA, Silvestri G, Scholl HPN, Kim IK, Ramke J, Tuo J, Merriam JE, Merriam JC, Park KH, Olson LM, Farrer LA, Johnson MP, Peachey NS, Lathrop M, Baron RV, Igo RP, Klein R, Hagstrom SA, Kamatani Y, Martin TM, Jiang Y, Conley Y, Sahel JA, Zack DJ, Chan CC, Pericak-Vance MA, Jacobson SG, Gorin MB, Klein ML, Allikmets R, Iyengar SK, Weber BH, Haines JL, Léveillard T, Deangelis MM, Stambolian D, Weeks DE, Bhattacharya SS, Chew EY, Heckenlively JR, Abecasis GR, Swaroop A. Rare and common variants in extracellular matrix gene Fibrillin 2 (FBN2) are associated with macular degeneration. Hum Mol Genet 2014; 23:5827-37. [PMID: 24899048 DOI: 10.1093/hmg/ddu276] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Neurodegenerative diseases affecting the macula constitute a major cause of incurable vision loss and exhibit considerable clinical and genetic heterogeneity, from early-onset monogenic disease to multifactorial late-onset age-related macular degeneration (AMD). As part of our continued efforts to define genetic causes of macular degeneration, we performed whole exome sequencing in four individuals of a two-generation family with autosomal dominant maculopathy and identified a rare variant p.Glu1144Lys in Fibrillin 2 (FBN2), a glycoprotein of the elastin-rich extracellular matrix (ECM). Sanger sequencing validated the segregation of this variant in the complete pedigree, including two additional affected and one unaffected individual. Sequencing of 192 maculopathy patients revealed additional rare variants, predicted to disrupt FBN2 function. We then undertook additional studies to explore the relationship of FBN2 to macular disease. We show that FBN2 localizes to Bruch's membrane and its expression appears to be reduced in aging and AMD eyes, prompting us to examine its relationship with AMD. We detect suggestive association of a common FBN2 non-synonymous variant, rs154001 (p.Val965Ile) with AMD in 10 337 cases and 11 174 controls (OR = 1.10; P-value = 3.79 × 10(-5)). Thus, it appears that rare and common variants in a single gene--FBN2--can contribute to Mendelian and complex forms of macular degeneration. Our studies provide genetic evidence for a key role of elastin microfibers and Bruch's membrane in maintaining blood-retina homeostasis and establish the importance of studying orphan diseases for understanding more common clinical phenotypes.
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Affiliation(s)
| | - Xiaowei Zhan
- Center for Statistical Genetics, Department of Biostatistics and
| | | | - Kari E Branham
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48109, USA
| | - David Zipprer
- Neurobiology Neurodegeneration and Repair Laboratory
| | - Christina F Chakarova
- Department of Genetics, UCL-Institute of Ophthalmology, Bath Street, London EC1V 9EL, UK
| | | | | | - Mohammad Othman
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48109, USA
| | | | | | - Naushin H Waseem
- Department of Genetics, UCL-Institute of Ophthalmology, Bath Street, London EC1V 9EL, UK
| | | | | | - Albert O Edwards
- Institute for Molecular Biology, University of Oregon and Oregon Retina, Eugene, OR 97401, USA
| | - Andrew Lotery
- Faculty of Medicine, Clinical and Experimental Sciences, University of Southampton, Southampton SO16 6YD, UK
| | - Barbara E Klein
- Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and, Public Health, Madison, WI 53726, USA
| | - Barbara J Truitt
- Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Bingshan Li
- Center for Human Genetics Research, Vanderbilt University, Nashville, TN 37232, USA
| | - Debra A Schaumberg
- Division of Preventive Medicine, Brigham and Women's Hospital, Boston, MA 02215, USA, Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah, Salt Lake City, UT 84132, USA
| | - Denise J Morgan
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah, Salt Lake City, UT 84132, USA
| | - Margaux A Morrison
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah, Salt Lake City, UT 84132, USA
| | - Eric Souied
- Hôpital Intercommunal de Créteil, Hôpital Henri Mondor - Université Paris Est Créteil 94000, France
| | - Evangelia E Tsironi
- Department of Ophthalmology, University of Thessaly School of Medicine, Larissa, Greece
| | - Felix Grassmann
- Institute of Human Genetics, University of Regensburg, Regensburg 93053, Germany
| | - Gerald A Fishman
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | | | - Hendrik P N Scholl
- Wilmer Eye Institute, Johns Hopkins University, 600 N. Wolfe Street, Baltimore, MD 21287, USA
| | - Ivana K Kim
- Retina Service and Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA
| | - Jacqueline Ramke
- The Fred Hollows Foundation, Auckland, New Zealand, School of Social Sciences, University of New South Wales, Sydney, Australia
| | | | | | | | - Kyu Hyung Park
- Department of Ophthalmology, Seoul National University Bundang Hospital, Seoul 463-707, Republic of Korea
| | - Lana M Olson
- Center for Human Genetics Research, Vanderbilt University, Nashville, TN 37232, USA
| | - Lindsay A Farrer
- Departments of Medicine (Section of Biomedical Genetics), Ophthalmology and Biostatistics, Neurology, Epidemiology, Boston University Schools of Medicine and Public Health, Boston, MA 02215, USA
| | | | - Neal S Peachey
- Cleveland Clinic Foundation, Cole Eye Institute, Cleveland, OH 44195, USA, Louis Stokes Cleveland VA Medical Center, Cleveland, OH 44195, USA
| | - Mark Lathrop
- Department of Genetics, Institut de la Vision - Inserm Université Pierre et Marie Curie UMR-S 968, Paris, France
| | | | - Robert P Igo
- Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Ronald Klein
- Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and, Public Health, Madison, WI 53726, USA
| | | | - Yoichiro Kamatani
- Department of Genetics, Institut de la Vision - Inserm Université Pierre et Marie Curie UMR-S 968, Paris, France
| | - Tammy M Martin
- Oregon Health & Science University, Portland, OR 97239, USA
| | - Yingda Jiang
- Department of Biostatistics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Yvette Conley
- Health Promotion and Development, School of Nursing, 440 Victoria Building, 3500 Victoria St, Pittsburgh, PA 15261, USA
| | - Jose-Alan Sahel
- Department of Genetics, Institut de la Vision - Inserm Université Pierre et Marie Curie UMR-S 968, Paris, France
| | - Donald J Zack
- Wilmer Eye Institute, Johns Hopkins University, 600 N. Wolfe Street, Baltimore, MD 21287, USA
| | | | - Margaret A Pericak-Vance
- Bascom Palmer Eye Institute and Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33125, USA
| | - Samuel G Jacobson
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Michael B Gorin
- Department of Ophthalmology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Michael L Klein
- Macular Degeneration Center, Casey Eye Institute, Oregon Health and Science, University, Portland, OR 97201, USA
| | - Rando Allikmets
- Department of Ophthalmology and Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Sudha K Iyengar
- Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Bernhard H Weber
- Institute of Human Genetics, University of Regensburg, Regensburg 93053, Germany
| | - Jonathan L Haines
- Center for Human Genetics Research, Vanderbilt University, Nashville, TN 37232, USA
| | - Thierry Léveillard
- Department of Genetics, Institut de la Vision - Inserm Université Pierre et Marie Curie UMR-S 968, Paris, France
| | - Margaret M Deangelis
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah, Salt Lake City, UT 84132, USA
| | - Dwight Stambolian
- Department of Ophthalmology, and Department of Genetics, University of Pennsylvania, Philadelphia, PA 9104, USA
| | - Daniel E Weeks
- Department of Human Genetics and Department of Biostatistics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Shomi S Bhattacharya
- Department of Genetics, UCL-Institute of Ophthalmology, Bath Street, London EC1V 9EL, UK
| | - Emily Y Chew
- Clinical Trials Branch, Division of Epidemiology and Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - John R Heckenlively
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48109, USA
| | | | - Anand Swaroop
- Neurobiology Neurodegeneration and Repair Laboratory,
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75
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Owsley C, Huisingh C, Jackson GR, Curcio CA, Szalai AJ, Dashti N, Clark M, Rookard K, McCrory MA, Wright TT, Callahan MA, Kline LB, Witherspoon CD, McGwin G. Associations between abnormal rod-mediated dark adaptation and health and functioning in older adults with normal macular health. Invest Ophthalmol Vis Sci 2014; 55:4776-89. [PMID: 24854857 DOI: 10.1167/iovs.14-14502] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
PURPOSE Delayed rod-mediated dark adaptation (DA) is characteristic of early age-related macular degeneration (AMD) and also can be observed in some older adults in normal macular health. We examine cross-sectional associations between rod-mediated DA and risk factors for AMD in older adults in normal macular health. METHODS The sample consisted of adults aged ≥60 years old in normal macular health per grading of fundus photos using an established disease classification system. Rod-mediated DA was measured psychophysically following a photobleach using a computer-automated dark adaptometer with targets centered at 5° on the inferior vertical meridian. The speed of DA was characterized by the rod-intercept value, with abnormal DA defined as rod-intercept ≥ 12.3 minutes. We assessed several health and functional characteristics that the literature has suggested increase AMD risk (e.g., smoking, alcohol use, inflammatory markers, apolipoproteins, low luminance visual acuity, chronic medical conditions, body mass, family history). RESULTS Among 381 participants (mean age, 68.5 years; SD, 5.5), 78% had normal and 22% had abnormal DA, with the prevalence of abnormal DA increasing with age. After age-adjustment, abnormal DA was associated with increased odds of elevated C-reactive protein (CRP), heavy use of or abstention from alcohol, high blood pressure, and drop in visual acuity under mesopic conditions. CONCLUSIONS Despite having normal macular health according to accepted definitions of AMD presence, approximately one-quarter of older adults recruited from primary eye care clinics had abnormal DA, which was associated with known risk factors for AMD, including elevated CRP.
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Affiliation(s)
- Cynthia Owsley
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Carrie Huisingh
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Gregory R Jackson
- Department of Ophthalmology, Penn State College of Medicine, Hershey, Pennsylvania, United States
| | - Christine A Curcio
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Alexander J Szalai
- Division of Clinical Immunology and Rheumatology, Department of Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Nassrin Dashti
- Division of Gerontology and Geriatrics, Department of Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Mark Clark
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Kia Rookard
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Mark A McCrory
- Division of Clinical Immunology and Rheumatology, Department of Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Tyler T Wright
- Division of Clinical Immunology and Rheumatology, Department of Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Michael A Callahan
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Lanning B Kline
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - C Douglas Witherspoon
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Gerald McGwin
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama, United States
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76
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Yang H, Zheng S, Qiu Y, Yang Y, Wang C, Yang P, Li Q, Lei B. Activation of liver X receptor alleviates ocular inflammation in experimental autoimmune uveitis. Invest Ophthalmol Vis Sci 2014; 55:2795-804. [PMID: 24699378 DOI: 10.1167/iovs.13-13323] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE To investigate whether a synthetic LXR agonist TO901317 (TO90) ameliorates ocular inflammation in a mouse model of experimental autoimmune uveitis (EAU) and to explore its underlying mechanism. METHODS EAU was induced with subcutaneous injection of IRBP161-180 peptide (SGIPYIISYLHPGNTILHVD) in B10.RIII mice. TO90 (50 mg/kg/d) or vehicle was administrated orally for successive 16 days or 8 days as prevention or effector phase, respectively. The severity of EAU was evaluated with clinical and histological scores. The levels of LXRs, NF-κB subunit p65, and an LXR target gene ABCA1 in the retina were detected with real-time PCR and Western blotting. The expressions of proinflammatory genes, including TNF-α, IL-1β, IL-6, MCP-1, IFN-γ, and IL-17, were detected by real-time PCR. IRBP-specific lymphocyte proliferation was detected by MTT. Intracellular IFN-γ and IL-17 in CD4(+) T cells were measured by flow cytometry. RESULTS We found both LXRα and LXRβ were expressed in mouse retina. After administering TO90 orally to B10.RIII mice, the expression of LXRα but not LXRβ was upregulated in the naïve mice. Compared with naïve mice, LXRα expression was increased in vehicle and TO90-treated EAU mice, but the LXRβ expression was unchanged. The protein level of ABCA1 was enhanced in TO90-treated naïve and EAU mice but was unchanged in vehicle-treated EAU mice, suggesting activation of LXRα by TO90 is ligand dependent. TO90-mediated activation of LXRα improved the clinical and morphological scores in EAU mice. Meanwhile, activation of LXRα decreased the expressions of proinflammatory cytokines, including TNF-α, IL-1β, IL-6, MCP-1, IFN-γ, and IL-17 in the retina. TO90 treatment inhibited IRBP-specific immune responses. The proportions of Th1 and Th17 expressing IFN-γ and IL-17 were reduced in TO90-treated EAU mice in both prevention and effector phases. Furthermore, TO90 significantly downregulated the expressions of an NF-κB subunit p65 at the protein and mRNA levels. CONCLUSIONS TO90 activates LXRα and potently attenuates ocular inflammation in EAU. Alleviation of ocular inflammation could partially result from inhibition of the NF-κB signaling pathway. TO90 reduces IFN-γ and IL-17 expression in both prevention and treatment scenarios. Our data suggest that the LXR agonist may become a novel class of therapeutic agent for autoimmune uveitis.
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Affiliation(s)
- Hongxia Yang
- Department of Ophthalmology, the First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing, China
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77
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Cholesterol in the retina: the best is yet to come. Prog Retin Eye Res 2014; 41:64-89. [PMID: 24704580 DOI: 10.1016/j.preteyeres.2014.03.002] [Citation(s) in RCA: 192] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 03/13/2014] [Accepted: 03/17/2014] [Indexed: 01/09/2023]
Abstract
Historically understudied, cholesterol in the retina is receiving more attention now because of genetic studies showing that several cholesterol-related genes are risk factors for age-related macular degeneration (AMD) and because of eye pathology studies showing high cholesterol content of drusen, aging Bruch's membrane, and newly found subretinal lesions. The challenge before us is determining how the cholesterol-AMD link is realized. Meeting this challenge will require an excellent understanding these genes' roles in retinal physiology and how chorioretinal cholesterol is maintained. In the first half of this review, we will succinctly summarize physico-chemical properties of cholesterol, its distribution in the human body, general principles of maintenance and metabolism, and differences in cholesterol handling in human and mouse that impact on experimental approaches. This information will provide a backdrop to the second part of the review focusing on unique aspects of chorioretinal cholesterol homeostasis, aging in Bruch's membrane, cholesterol in AMD lesions, a model for lesion biogenesis, a model for macular vulnerability based on vascular biology, and alignment of AMD-related genes and pathobiology using cholesterol and an atherosclerosis-like progression as unifying features. We conclude with recommendations for the most important research steps we can take towards delineating the cholesterol-AMD link.
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78
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Li M, Jia C, Kazmierkiewicz KL, Bowman AS, Tian L, Liu Y, Gupta NA, Gudiseva HV, Yee SS, Kim M, Dentchev T, Kimble JA, Parker JS, Messinger JD, Hakonarson H, Curcio CA, Stambolian D. Comprehensive analysis of gene expression in human retina and supporting tissues. Hum Mol Genet 2014; 23:4001-14. [PMID: 24634144 PMCID: PMC7297232 DOI: 10.1093/hmg/ddu114] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Understanding the influence of gene expression on the molecular mechanisms underpinning human phenotypic diversity is fundamental to being able to predict health outcomes and treat disease. We have carried out whole transcriptome expression analysis on a series of eight normal human postmortem eyes by RNA sequencing. Here we present data showing that ∼80% of the transcriptome is expressed in the posterior layers of the eye and that there is significant differential expression not only between the layers of the posterior part of the eye but also between locations of a tissue layer. These differences in expression also extend to alternative splicing and splicing factors. Differentially expressed genes are enriched for genes associated with psychiatric, immune and cardiovascular disorders. Enrichment categories for gene ontology included ion transport, synaptic transmission and visual and sensory perception. Lastly, allele-specific expression was found to be significant forCFH,C3 andCFB, which are known risk genes for age-related macular degeneration. These expression differences should be useful in determining the underlying biology of associations with common diseases of the human retina, retinal pigment epithelium and choroid and in guiding the analysis of the genomic regions involved in the control of normal gene expression.
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Affiliation(s)
- Mingyao Li
- Department of Biostatistics and Epidemiology
| | - Cheng Jia
- Department of Biostatistics and Epidemiology
| | | | | | | | - Yichuan Liu
- Department of Biostatistics and Epidemiology
| | - Neel A Gupta
- College of Medicine, Drexel University, Philadelphia, PA 19104, USA
| | | | | | | | | | - James A Kimble
- Retina Specialists of Alabama, Birmingham, AL 35294, USA Department of Ophthalmology, University of Alabama School of Medicine, Birmingham, AL 35294, USA
| | - John S Parker
- Department of Ophthalmology, University of Alabama School of Medicine, Birmingham, AL 35294, USA
| | - Jeffrey D Messinger
- Department of Ophthalmology, University of Alabama School of Medicine, Birmingham, AL 35294, USA
| | - Hakon Hakonarson
- Department of Pediatrics, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA Division of Pulmonary Medicine and The Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Christine A Curcio
- Department of Ophthalmology, University of Alabama School of Medicine, Birmingham, AL 35294, USA
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Mechanism of inflammation in age-related macular degeneration: an up-to-date on genetic landmarks. Mediators Inflamm 2013; 2013:435607. [PMID: 24369445 PMCID: PMC3863457 DOI: 10.1155/2013/435607] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 09/28/2013] [Indexed: 12/13/2022] Open
Abstract
Age-related macular degeneration (AMD) is the most common cause of irreversible visual impairment among people over 50 years of age, accounting for up to 50% of all cases of legal blindness in Western countries. Although the aging represents the main determinant of AMD, it must be considered a multifaceted disease caused by interactions among environmental risk factors and genetic backgrounds. Mounting evidence and/or arguments document the crucial role of inflammation and immune-mediated processes in the pathogenesis of AMD. Proinflammatory effects secondary to chronic inflammation (e.g., alternative complement activation) and heterogeneous types of oxidative stress (e.g., impaired cholesterol homeostasis) can result in degenerative damages at the level of crucial macular structures, that is photoreceptors, retinal pigment epithelium, and Bruch's membrane. In the most recent years, the association of AMD with genes, directly or indirectly, involved in immunoinflammatory pathways is increasingly becoming an essential core for AMD knowledge. Starting from the key basic-research notions detectable at the root of AMD pathogenesis, the present up-to-date paper reviews the best-known and/or the most attractive genetic findings linked to the mechanisms of inflammation of this complex disease.
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80
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Du M, Wu M, Fu D, Yang S, Chen J, Wilson K, Lyons TJ. Effects of modified LDL and HDL on retinal pigment epithelial cells: a role in diabetic retinopathy? Diabetologia 2013; 56:2318-28. [PMID: 23842729 PMCID: PMC4557884 DOI: 10.1007/s00125-013-2986-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 06/17/2013] [Indexed: 10/26/2022]
Abstract
AIMS/HYPOTHESIS Blood-retina barrier leakage in diabetes results in extravasation of plasma lipoproteins. Intra-retinal modified LDLs have been implicated in diabetic retinopathy (DR), but their effects on retinal pigment epithelial (RPE) cells and the added effects of extravasated modified HDLs are unknown. METHODS In human retinas from individuals with and without diabetes and DR, immunohistochemistry was used to detect ApoB, ApoA1 and endoplasmic reticulum (ER) stress markers. In cell culture, human RPE cells were treated with native LDL (N-LDL) or heavily-oxidised glycated LDL (HOG-LDL) with or without pretreatment with native HDL (N-HDL) or heavily-oxidised glycated HDL (HOG-HDL). Cell viability, oxidative stress, ER stress, apoptosis and autophagy were assessed by Cell Counting Kit-8 assay, dichlorofluorescein assay, western blotting, immunofluorescence and TUNEL assay. In separate experiments, RPE cells were treated with lipid oxidation products, 7-ketocholesterol (7-KC, 5-40 μmol/l) or 4-hydroxynonenal (4-HNE, 5-80 μmol/l), with or without pretreatment with N-HDL or HOG-HDL. RESULTS ApoB, ApoA1 staining and RPE ER stress were increased in the presence of DR. HOG-LDL but not N-LDL significantly decreased RPE cell viability and increased reactive oxygen species generation, ER stress, apoptosis and autophagy. Similarly, 4-HNE and 7-KC decreased viability and induced ER stress. Pretreatment with N-HDL mitigated these effects, whereas HOG-HDL was less effective by most, but not all, measures. CONCLUSIONS/INTERPRETATION In DR, extravascular modified LDL may promote RPE injury through oxidative stress, ER stress, autophagy and apoptosis. N-HDL has protective effects, but HOG-HDL is less effective. Extravasation and modification of HDL may modulate the injurious effects of extravasated modified LDL on the retinal pigment epithelium.
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Affiliation(s)
- M. Du
- Harold Hamm Diabetes Center and Section of Endocrinology and Diabetes, University of Oklahoma Health Sciences Center, HHDC Suite 2900, Oklahoma City, OK 73104, USA
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - M. Wu
- Harold Hamm Diabetes Center and Section of Endocrinology and Diabetes, University of Oklahoma Health Sciences Center, HHDC Suite 2900, Oklahoma City, OK 73104, USA
| | - D. Fu
- Harold Hamm Diabetes Center and Section of Endocrinology and Diabetes, University of Oklahoma Health Sciences Center, HHDC Suite 2900, Oklahoma City, OK 73104, USA
- Department of Immunology, Harbin Medical University, Harbin, People’s Republic of China
| | - S. Yang
- Harold Hamm Diabetes Center and Section of Endocrinology and Diabetes, University of Oklahoma Health Sciences Center, HHDC Suite 2900, Oklahoma City, OK 73104, USA
| | - J. Chen
- Harold Hamm Diabetes Center and Section of Endocrinology and Diabetes, University of Oklahoma Health Sciences Center, HHDC Suite 2900, Oklahoma City, OK 73104, USA
| | - K. Wilson
- Harold Hamm Diabetes Center and Section of Endocrinology and Diabetes, University of Oklahoma Health Sciences Center, HHDC Suite 2900, Oklahoma City, OK 73104, USA
| | - T. J. Lyons
- Harold Hamm Diabetes Center and Section of Endocrinology and Diabetes, University of Oklahoma Health Sciences Center, HHDC Suite 2900, Oklahoma City, OK 73104, USA
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Chen J, Pikuleva IA, Turko IV. Mass spectrometry quantification of PICALM and AP180 in human frontal cortex and neural retina. Anal Biochem 2013; 442:253-8. [PMID: 23954523 DOI: 10.1016/j.ab.2013.08.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 08/01/2013] [Accepted: 08/07/2013] [Indexed: 11/18/2022]
Abstract
Recent genome-wide association studies have suggested that endocytic factors, such as phosphatidylinositol-binding clathrin assembly protein (PICALM), may be implicated in the development of Alzheimer disease (AD). The cellular functions of PICALM are in line with this possibility: (i) PICALM is involved in regulation of amyloid-β levels and (ii) PICALM is important for a presynaptic function, which is diminished in AD. To facilitate the analysis of PICALM, we developed a quantitative method to assess the expression level of PICALM in various biological samples. For this purpose, a stable isotope-labeled quantification concatamer (QconCAT) of PICALM was designed, expressed, purified, and characterized. The PICALM QconCAT was first used as an internal standard in a multiple reaction monitoring assay to measure PICALM concentrations in the human frontal cortex, a tissue strongly affected by AD. A second endocytic factor that is highly homologous to PICALM and also functions in clathrin-mediated endocytosis, clathrin coat assembly protein AP180, was quantified as well. Because age-related macular degeneration shares several clinical and pathological features with AD, the measurements were then extended to human normal neural retina. Overall, the developed method is suitable for PICALM and AP180 quantitative analysis in various biological samples of interest.
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Affiliation(s)
- Junjun Chen
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA; Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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SanGiovanni JP, Neuringer M. The putative role of lutein and zeaxanthin as protective agents against age-related macular degeneration: promise of molecular genetics for guiding mechanistic and translational research in the field. Am J Clin Nutr 2012; 96:1223S-33S. [PMID: 23053548 PMCID: PMC3471204 DOI: 10.3945/ajcn.112.038240] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Age-related macular degeneration (AMD) is the primary cause of vision loss in elderly people of western European ancestry. Genetic, dietary, and environmental factors affect tissue concentrations of macular xanthophylls (MXs) within retinal cell types manifesting AMD pathology. In this article we review the history and state of science on the putative role of the MXs (lutein, zeaxanthin, and meso-zeaxanthin) in AMD and report findings on AMD-associated genes encoding enzymes, transporters, ligands, and receptors affecting or affected by MXs. We then use this context to discuss emerging research opportunities that offer promise for meaningful investigation and inference in the field.
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83
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Meaney S. Epigenetic regulation of oxysterol formation. Biochimie 2012; 95:531-7. [PMID: 22986023 DOI: 10.1016/j.biochi.2012.08.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 08/31/2012] [Indexed: 11/26/2022]
Abstract
Oxysterols are oxygenated derivatives of cholesterol that may be formed by either enzymatic or non-enzymatic mechanisms. Expression of the genes responsible for oxysterol synthesis (GROS) is known to be restricted across different tissues and cell types. Regulation of the transcription of GROS and the activity of their enzyme transcripts has been the subject of intense activity for many years. Recent studies have sought to decipher the mechanism(s) that underpin the restricted expression of the GROS. Available data indicates that epigenetic mechanisms have an important role to play in the control of the expression of GROS. In the current review we summarize the available evidence for the epigenetic regulation of these genes.
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Affiliation(s)
- Steve Meaney
- School of Biological Sciences, College of Sciences and Health, Dublin Institute of Technology, Kevin Street, Dublin 8, Ireland.
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