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Thankam FG, Chandra IS, Kovilam AN, Diaz CG, Volberding BT, Dilisio MF, Radwan MM, Gross RM, Agrawal DK. Amplification of Mitochondrial Activity in the Healing Response Following Rotator Cuff Tendon Injury. Sci Rep 2018; 8:17027. [PMID: 30451947 PMCID: PMC6242817 DOI: 10.1038/s41598-018-35391-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 10/31/2018] [Indexed: 02/07/2023] Open
Abstract
Mitochondrial function following rotator cuff tendon injury (RCI) influences the tendon healing. We examined the mitochondrial morphology and function under hypoxia in the shoulder tendon tissue from surgically-induced tenotomy-RCI rat model and cultured swine tenocytes. The tendon tissue was collected post-injury on 3-5 (Group-A), 10-12 (Group-B), and 22-24 (Group-C), days and the corresponding contralateral tendons were used as control for each group. There was higher protein expression of citrate synthase (P < 0.0001) [10.22 MFI (mean fluorescent intensity)] and complex-1 (P = 0.0008) (7.86 MFI) in Group-A and Group-B that decreased in Group-C [(P = 0.0201) (5.78 MFI and (P = 0.7915) (2.32 MFI), respectively] compared to control tendons. The ratio of BAX:Bcl2 (Bcl2 associated x protein:B cell lymphoma 2) in RCI tendons increased by 50.5% (Group-A) and 68.4% (Group-B) and decreased by 25.8% (Group-C) compared to normoxic controls. Hypoxia increased β-tubulin expression (P = 0067) and reduced PGC1-α (P = 0412) expression in the isolated swine tenocytes with no effect on the protein expression of Complex-1 (P = 7409) and citrate synthase (P = 0.3290). Also, the hypoxic tenocytes exhibited about 4-fold increase in mitochondrial superoxide (P < 0.0001), altered morphology and mitochondrial pore integrity, and increase in mitochondrial density compared to normoxic controls. These findings suggest the critical role of mitochondria in the RCI healing response.
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Affiliation(s)
- Finosh G Thankam
- Departments of Clinical & Translational Science and Orthopedic Surgery, Creighton University School of Medicine, Omaha, NE, 68178, USA
| | - Isaiah S Chandra
- Departments of Clinical & Translational Science and Orthopedic Surgery, Creighton University School of Medicine, Omaha, NE, 68178, USA
| | - Anuradha N Kovilam
- Departments of Clinical & Translational Science and Orthopedic Surgery, Creighton University School of Medicine, Omaha, NE, 68178, USA
| | - Connor G Diaz
- Departments of Clinical & Translational Science and Orthopedic Surgery, Creighton University School of Medicine, Omaha, NE, 68178, USA
| | - Benjamin T Volberding
- Departments of Clinical & Translational Science and Orthopedic Surgery, Creighton University School of Medicine, Omaha, NE, 68178, USA
| | - Matthew F Dilisio
- Departments of Clinical & Translational Science and Orthopedic Surgery, Creighton University School of Medicine, Omaha, NE, 68178, USA
| | - Mohamed M Radwan
- Departments of Clinical & Translational Science and Orthopedic Surgery, Creighton University School of Medicine, Omaha, NE, 68178, USA
| | - R Michael Gross
- Departments of Clinical & Translational Science and Orthopedic Surgery, Creighton University School of Medicine, Omaha, NE, 68178, USA
| | - Devendra K Agrawal
- Departments of Clinical & Translational Science and Orthopedic Surgery, Creighton University School of Medicine, Omaha, NE, 68178, USA.
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52
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Pharmaceutical Induction of PGC-1 α Promotes Retinal Pigment Epithelial Cell Metabolism and Protects against Oxidative Damage. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:9248640. [PMID: 30524663 PMCID: PMC6247391 DOI: 10.1155/2018/9248640] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 09/14/2018] [Indexed: 01/05/2023]
Abstract
Retinal pigment epithelium (RPE) dysfunction due to accumulation of reactive oxygen species and oxidative damage is a key event in the development of age-related macular degeneration (AMD). Here, we examine the therapeutic potential of ZLN005, a selective PGC-1α transcriptional regulator, in protecting RPE from cytotoxic oxidative damage. Gene expression analysis on ARPE-19 cells treated with ZLN005 shows robust upregulation of PGC-1α and its associated transcription factors, antioxidant enzymes, and mitochondrial genes. Energetic profiling shows that ZLN005 treatment enhances RPE mitochondrial function by increasing basal and maximal respiration rates, and spare respiratory capacity. In addition, ZLN005 robustly protects ARPE-19 cells from cell death caused by H2O2, ox-LDL, and NaIO3 without exhibiting any cytotoxicity under basal conditions. ZLN005 protection against H2O2-mediated cell death was lost in PGC-1α-silenced cells. Our data indicates that ZLN005 efficiently protects RPE cells from oxidative damage through selective induction of PGC-1α and its target antioxidant enzymes. ZLN005 may serve as a novel therapeutic agent for retinal diseases associated with RPE dystrophies.
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53
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Dhingra A, Bell BA, Peachey NS, Daniele LL, Reyes-Reveles J, Sharp RC, Jun B, Bazan NG, Sparrow JR, Kim HJ, Philp NJ, Boesze-Battaglia K. Microtubule-Associated Protein 1 Light Chain 3B, (LC3B) Is Necessary to Maintain Lipid-Mediated Homeostasis in the Retinal Pigment Epithelium. Front Cell Neurosci 2018; 12:351. [PMID: 30349463 PMCID: PMC6186781 DOI: 10.3389/fncel.2018.00351] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 09/19/2018] [Indexed: 12/25/2022] Open
Abstract
Like other neurons, retinal cells utilize autophagic pathways to maintain cell homeostasis. The mammalian retina relies on heterophagy and selective autophagy to efficiently degrade and metabolize ingested lipids with disruption in autophagy associated degradation contributing to age related retinal disorders. The retinal pigment epithelium (RPE) supports photoreceptor cell renewal by daily phagocytosis of shed photoreceptor outer segments (OS). The daily ingestion of these lipid-rich OS imposes a constant degradative burden on these terminally differentiated cells. These cells rely on Microtubule-Associated Protein 1 Light Chain 3 (LC3) family of proteins for phagocytic clearance of the ingested OS. The LC3 family comprises of three highly homologous members, MAP1LC3A (LC3A), MAP1LC3B (LC3B), and MAP1LC3C (LC3C). The purpose of this study was to determine whether the LC3B isoform plays a specific role in maintaining RPE lipid homeostasis. We examined the RPE and retina of the LC3B-/- mouse as a function of age using in vivo ocular imaging and electroretinography coupled with ex vivo, lipidomic analyses of lipid mediators, assessment of bisretinoids as well as imaging of lipid aggregates. Deletion of LC3B resulted in defects within the RPE including increased phagosome accumulation, decreased fatty acid oxidation and a subsequent increase in RPE and sub-RPE lipid deposits. Age-dependent RPE changes included elevated levels of oxidized cholesterol, deposition of 4-HNE lipid peroxidation products, bisretinoid lipofuscin accumulation, and subretinal migration of microglia, collectively likely contributing to loss of retinal function. These observations are consistent with a critical role for LC3B-dependent processes in the maintenance of normal lipid homeostasis in the aging RPE, and suggest that LC3 isoform specific disruption in autophagic processes contribute to AMD-like pathogenesis.
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Affiliation(s)
- Anuradha Dhingra
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Brent A Bell
- Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, United States
| | - Neal S Peachey
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH, United States.,Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States.,Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Lauren L Daniele
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Juan Reyes-Reveles
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Rachel C Sharp
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Bokkyoo Jun
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, LA, United States
| | - Nicolas G Bazan
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, LA, United States
| | - Janet R Sparrow
- Department of Ophthalmology, Columbia University Medical Center, New York, NY, United States
| | - Hye Jin Kim
- Department of Ophthalmology, Columbia University Medical Center, New York, NY, United States
| | - Nancy J Philp
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Kathleen Boesze-Battaglia
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, United States
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54
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Felszeghy S, Viiri J, Paterno JJ, Hyttinen JMT, Koskela A, Chen M, Leinonen H, Tanila H, Kivinen N, Koistinen A, Toropainen E, Amadio M, Smedowski A, Reinisalo M, Winiarczyk M, Mackiewicz J, Mutikainen M, Ruotsalainen AK, Kettunen M, Jokivarsi K, Sinha D, Kinnunen K, Petrovski G, Blasiak J, Bjørkøy G, Koskelainen A, Skottman H, Urtti A, Salminen A, Kannan R, Ferrington DA, Xu H, Levonen AL, Tavi P, Kauppinen A, Kaarniranta K. Loss of NRF-2 and PGC-1α genes leads to retinal pigment epithelium damage resembling dry age-related macular degeneration. Redox Biol 2018; 20:1-12. [PMID: 30253279 PMCID: PMC6156745 DOI: 10.1016/j.redox.2018.09.011] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 09/06/2018] [Accepted: 09/13/2018] [Indexed: 12/30/2022] Open
Abstract
Age-related macular degeneration (AMD) is a multi-factorial disease that is the leading cause of irreversible and severe vision loss in the developed countries. It has been suggested that the pathogenesis of dry AMD involves impaired protein degradation in retinal pigment epithelial cells (RPE). RPE cells are constantly exposed to oxidative stress that may lead to the accumulation of damaged cellular proteins, DNA and lipids and evoke tissue deterioration during the aging process. The ubiquitin-proteasome pathway and the lysosomal/autophagosomal pathway are the two major proteolytic systems in eukaryotic cells. NRF-2 (nuclear factor-erythroid 2-related factor-2) and PGC-1α (peroxisome proliferator-activated receptor gamma coactivator-1 alpha) are master transcription factors in the regulation of cellular detoxification. We investigated the role of NRF-2 and PGC-1α in the regulation of RPE cell structure and function by using global double knockout (dKO) mice. The NRF-2/PGC-1α dKO mice exhibited significant age-dependent RPE degeneration, accumulation of the oxidative stress marker, 4-HNE (4-hydroxynonenal), the endoplasmic reticulum stress markers GRP78 (glucose-regulated protein 78) and ATF4 (activating transcription factor 4), and damaged mitochondria. Moreover, levels of protein ubiquitination and autophagy markers p62/SQSTM1 (sequestosome 1), Beclin-1 and LC3B (microtubule associated protein 1 light chain 3 beta) were significantly increased together with the Iba-1 (ionized calcium binding adaptor molecule 1) mononuclear phagocyte marker and an enlargement of RPE size. These histopathological changes of RPE were accompanied by photoreceptor dysmorphology and vision loss as revealed by electroretinography. Consequently, these novel findings suggest that the NRF-2/PGC-1α dKO mouse is a valuable model for investigating the role of proteasomal and autophagy clearance in the RPE and in the development of dry AMD. NRF-2/PGC-1α dKO mouse model shows a dry AMD-like phenotype. Loss of NRF-2/PGC-1α genes increased oxidative and ER stress in RPE cells. High oxidative stress was associated with impaired autophagy and proteasomal clearance. The pathology becomes manifest as an age-related loss of photoreceptor function.
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Affiliation(s)
- Szabolcs Felszeghy
- Institute of Dentistry, University of Eastern Finland, Kuopio, Finland; Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Johanna Viiri
- Department of Ophthalmology, University of Eastern Finland, Kuopio, Finland
| | - Jussi J Paterno
- Department of Ophthalmology, University of Eastern Finland, Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, Kuopio, Finland
| | - Juha M T Hyttinen
- Department of Ophthalmology, University of Eastern Finland, Kuopio, Finland
| | - Ali Koskela
- Department of Ophthalmology, University of Eastern Finland, Kuopio, Finland
| | - Mei Chen
- The Wellcome-Wolfson Institute of Experimental Medicine Queen's University Belfast, Belfast, UK
| | - Henri Leinonen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Heikki Tanila
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Niko Kivinen
- Department of Ophthalmology, University of Eastern Finland, Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, Kuopio, Finland
| | - Arto Koistinen
- SIB Labs, University of Eastern Finland, Kuopio, Finland
| | - Elisa Toropainen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
| | - Marialaura Amadio
- Department of Drug Sciences, Section of Pharmacology, University of Pavia, Pavia, Italy
| | - Adrian Smedowski
- Chair and Department of Physiology, School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland
| | - Mika Reinisalo
- Department of Ophthalmology, University of Eastern Finland, Kuopio, Finland; School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
| | - Mateusz Winiarczyk
- Department of Epizootiology, University of Life Sciences of Lublin, Poland; Department of Vitreoretinal Surgery, Medical University of Lublin, Poland
| | - Jerzy Mackiewicz
- Department of Vitreoretinal Surgery, Medical University of Lublin, Poland
| | - Maija Mutikainen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Anna-Kaisa Ruotsalainen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Mikko Kettunen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Kimmo Jokivarsi
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Debasish Sinha
- The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Kati Kinnunen
- Department of Ophthalmology, Kuopio University Hospital, Kuopio, Finland
| | - Goran Petrovski
- Centre of Eye Research, Department of Ophthalmology, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Janusz Blasiak
- Department of Molecular Genetics, University of Lodz, Lodz, Poland
| | - Geir Bjørkøy
- Centre of Molecular Inflammation Research and Department of Cancer Research and Molecular Medicine; Norwegian University of Science and Technology and Department of Technology; University College of Sør-Trøndelag, Trondheim, Norway
| | - Ari Koskelainen
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Aalto, Finland
| | - Heli Skottman
- Faculty of Medicine and Life Sciences, BioMediTech Institute, University of Tampere, Tampere, Finland
| | - Arto Urtti
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland; Centre for Drug Research, Division of Pharmaceutical Biosciences, University of Helsinki, Helsinki, Finland
| | - Antero Salminen
- Department of Neurology, University of Eastern Finland, Kuopio, Finland
| | - Ram Kannan
- Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Los Angeles, CA, USA
| | - Deborah A Ferrington
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, USA
| | - Heping Xu
- The Wellcome-Wolfson Institute of Experimental Medicine Queen's University Belfast, Belfast, UK
| | - Anna-Liisa Levonen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Pasi Tavi
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Anu Kauppinen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
| | - Kai Kaarniranta
- Department of Ophthalmology, University of Eastern Finland, Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, Kuopio, Finland.
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55
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Zhang M, Chu Y, Mowery J, Konkel B, Galli S, Theos AC, Golestaneh N. Pgc-1α repression and high-fat diet induce age-related macular degeneration-like phenotypes in mice. Dis Model Mech 2018; 11:dmm.032698. [PMID: 29925537 PMCID: PMC6176989 DOI: 10.1242/dmm.032698] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 06/13/2018] [Indexed: 12/28/2022] Open
Abstract
Age-related macular degeneration (AMD) is the major cause of blindness in the elderly in developed countries and its prevalence is increasing with the aging population. AMD initially affects the retinal pigment epithelium (RPE) and gradually leads to secondary photoreceptor degeneration. Recent studies have associated mitochondrial damage with AMD, and we have observed mitochondrial and autophagic dysfunction and repressed peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α; also known as Ppargc1a) in native RPE from AMD donor eyes and their respective induced pluripotent stem cell-derived RPE. To further investigate the effect of PGC-1α repression, we have established a mouse model by feeding Pgc-1α+/− mice with a high-fat diet (HFD) and investigated RPE and retinal health. We show that when mice expressing lower levels of Pgc-1α are exposed to HFD, they present AMD-like abnormalities in RPE and retinal morphology and function. These abnormalities include basal laminar deposits, thickening of Bruch's membrane with drusen marker-containing deposits, RPE and photoreceptor degeneration, decreased mitochondrial activity, increased levels of reactive oxygen species, decreased autophagy dynamics/flux, and increased inflammatory response in the RPE and retina. Our study shows that Pgc-1α is important in outer retina biology and that Pgc-1α+/− mice fed with HFD provide a promising model to study AMD, opening doors for novel treatment strategies. Summary: A new mouse model has been established that exhibits characteristics of human age-related macular degeneration; the model will facilitate further studies of AMD disease mechanisms.
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Affiliation(s)
- Meng Zhang
- Department of Ophthalmology, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Yi Chu
- Department of Ophthalmology, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Joseph Mowery
- Electron and Confocal Microscopy Unit, USDA Agricultural Research Service, Beltsville, MD 20705, USA
| | - Brandon Konkel
- Department of Biochemistry and Molecular and Cellular Biology, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Susana Galli
- Department of Biochemistry and Molecular and Cellular Biology, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Alexander C Theos
- Department of Human Science, Georgetown University, Washington, DC 20057, USA
| | - Nady Golestaneh
- Department of Ophthalmology, Georgetown University Medical Center, Washington, DC 20057, USA .,Department of Biochemistry and Molecular and Cellular Biology, Georgetown University Medical Center, Washington, DC 20057, USA.,Department of Neurology, Georgetown University Medical Center, Washington, DC 20057, USA
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56
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Kaarniranta K, Kajdanek J, Morawiec J, Pawlowska E, Blasiak J. PGC-1α Protects RPE Cells of the Aging Retina against Oxidative Stress-Induced Degeneration through the Regulation of Senescence and Mitochondrial Quality Control. The Significance for AMD Pathogenesis. Int J Mol Sci 2018; 19:ijms19082317. [PMID: 30087287 PMCID: PMC6121367 DOI: 10.3390/ijms19082317] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/18/2018] [Accepted: 08/05/2018] [Indexed: 02/07/2023] Open
Abstract
PGC-1α (peroxisome proliferator-activated receptor gamma coactivator 1-alpha) is a transcriptional coactivator of many genes involved in energy management and mitochondrial biogenesis. PGC-1α expression is associated with cellular senescence, organismal aging, and many age-related diseases, including AMD (age-related macular degeneration), an important global issue concerning vision loss. We and others have developed a model of AMD pathogenesis, in which stress-induced senescence of retinal pigment epithelium (RPE) cells leads to AMD-related pathological changes. PGC-1α can decrease oxidative stress, a key factor of AMD pathogenesis related to senescence, through upregulation of antioxidant enzymes and DNA damage response. PGC-1α is an important regulator of VEGF (vascular endothelial growth factor), which is targeted in the therapy of wet AMD, the most devastating form of AMD. Dysfunction of mitochondria induces cellular senescence associated with AMD pathogenesis. PGC-1α can improve mitochondrial biogenesis and negatively regulate senescence, although this function of PGC-1α in AMD needs further studies. Post-translational modifications of PGC-1α by AMPK (AMP kinase) and SIRT1 (sirtuin 1) are crucial for its activation and important in AMD pathogenesis.
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Affiliation(s)
- Kai Kaarniranta
- Department of Ophthalmology, University of Eastern Finland, 70211 Kuopio, Finland.
- Department of Ophthalmology, Kuopio University Hospital, 70029 Kuopio, Finland.
| | - Jakub Kajdanek
- Department of Molecular Genetics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland.
| | - Jan Morawiec
- Department of General and Colorectal Surgery, Medical University of Lodz, Pl. Hallera 1, 90-647 Lodz, Poland.
| | - Elzbieta Pawlowska
- Department of Orthodontics, Medical University of Lodz, Pomorska 251, 92-216 Lodz, Poland.
| | - Janusz Blasiak
- Department of Molecular Genetics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland.
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Hyttinen JMT, Viiri J, Kaarniranta K, Błasiak J. Mitochondrial quality control in AMD: does mitophagy play a pivotal role? Cell Mol Life Sci 2018; 75:2991-3008. [PMID: 29777261 PMCID: PMC11105454 DOI: 10.1007/s00018-018-2843-7] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 04/25/2018] [Accepted: 05/16/2018] [Indexed: 01/05/2023]
Abstract
Age-related macular degeneration (AMD) is the predominant cause of visual loss in old people in the developed world, whose incidence is increasing. This disease is caused by the decrease in macular function, due to the degeneration of retinal pigment epithelium (RPE) cells. The aged retina is characterised by increased levels of reactive oxygen species (ROS), impaired autophagy, and DNA damage that are linked to AMD pathogenesis. Mitophagy, a mitochondria-specific type of autophagy, is an essential part of mitochondrial quality control, the collective mechanism responsible for this organelle's homeostasis. The abundance of ROS, DNA damage, and the excessive energy consumption in the ageing retina all contribute to the degeneration of RPE cells and their mitochondria. We discuss the role of mitophagy in the cell and argue that its impairment may play a role in AMD pathogenesis. Thus, mitophagy as a potential therapeutic target in AMD and other degenerative diseases is as well explored.
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Affiliation(s)
- Juha M T Hyttinen
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland.
| | - Johanna Viiri
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland
- Department of Ophthalmology, Kuopio University Hospital, P.O. Box 100, 70029 KYS, Kuopio, Finland
| | - Janusz Błasiak
- Department of Molecular Genetics, University of Łódź, Pomorska 141/143, 90-236, Łódź, Poland
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Sun Y, Zheng Y, Wang C, Liu Y. Glutathione depletion induces ferroptosis, autophagy, and premature cell senescence in retinal pigment epithelial cells. Cell Death Dis 2018; 9:753. [PMID: 29988039 PMCID: PMC6037763 DOI: 10.1038/s41419-018-0794-4] [Citation(s) in RCA: 315] [Impact Index Per Article: 52.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 06/09/2018] [Accepted: 06/14/2018] [Indexed: 12/28/2022]
Abstract
Glutathione (GSH) protects against oxidative damage in many tissues, including retinal pigment epithelium (RPE). Oxidative stress-mediated senescence and death of RPE and subsequent death of photoreceptors have been observed in age-related macular degeneration (AMD). Although the consequences of GSH depletion have been described previously, questions remain regarding the molecular mechanisms. We herein examined the downstream effects of GSH depletion on stress-induced premature senescence (SIPS) and cell death in human RPE cells. Briefly, cultured ARPE-19 cells were depleted of GSH using: (1) incubation in cystine (Cys2)-free culture medium; (2) treatment with buthionine sulphoximine (BSO, 1000 µM) to block de novo GSH synthesis for 24-48 h; or (3) treatment with erastin (10 µM for 12-24 h) to inhibit Cys2/glutamate antiporter (system xc-). These treatments decreased cell viability and increased both soluble and lipid reactive oxygen species (ROS) generation but did not affect mitochondrial ROS or mitochondrial mass. Western blot analysis revealed decreased expression of ferroptotic modulator glutathione peroxidase 4 (GPX4). Increased autophagy was apparent, as reflected by increased LC3 expression, autophagic vacuoles, and autophagic flux. In addition, GSH depletion induced SIPS, as evidenced by increased percentage of the senescence-associated β-galactosidase-positive cells, increased senescence-associated heterochromatin foci (SAHF), as well as cell cycle arrest at the G1 phase. GSH depletion-dependent cell death was prevented by selective ferroptosis inhibitors (8 μM Fer-1 and 600 nM Lip-1), iron chelator DFO (80 μM), as well as autophagic inhibitors Baf-A1 (75 nM) and 3-MA (10 mM). Inhibiting autophagy with Baf-A1 (75 nM) or 3-MA (10 mM) promoted SIPS. In contrast, inducing autophagy with rapamycin (100 nM) attenuated SIPS. Our findings suggest that GSH depletion induces ferroptosis, autophagy, and SIPS. In addition, we found that autophagy is activated in the process of ferroptosis and reduces SIPS, suggesting an essential role of autophagy in ferroptosis and SIPS.
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Affiliation(s)
- Yun Sun
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Yingfeng Zheng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Chunxiao Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Yizhi Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
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59
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High throughput screening of mitochondrial bioenergetics in human differentiated myotubes identifies novel enhancers of muscle performance in aged mice. Sci Rep 2018; 8:9408. [PMID: 29925868 PMCID: PMC6010423 DOI: 10.1038/s41598-018-27614-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 05/31/2018] [Indexed: 01/01/2023] Open
Abstract
Mitochondrial dysfunction is increasingly recognized as a contributor to age-related muscle loss and functional impairment. Therefore, we developed a high throughput screening strategy that enabled the identification of compounds boosting mitochondrial energy production in a human skeletal muscle cell model. Screening of 7949 pure natural products revealed 22 molecules that significantly increased oxygen consumption and ATP levels in myotubes. One of the most potent compounds was the flavanone hesperetin. Hesperetin (10 µM) increased intracellular ATP by 33% and mitochondrial spare capacity by 25%. Furthermore, the compound reduced oxidative stress in primary myotubes as well as muscle tissue in vivo. In aged mice administration of hesperetin (50 mg/kg/d) completely reverted the age-related decrease of muscle fiber size and improved running performance of treated animals. These results provide a novel screening platform for the discovery of drugs that can improve skeletal muscle function in patients suffering from sarcopenia or other disorders associated with mitochondrial dysfunction.
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Shen R, Liu D, Hou C, Liu D, Zhao L, Cheng J, Wang D, Bai D. Protective effect of Potentilla anserina polysaccharide on cadmium-induced nephrotoxicity in vitro and in vivo. Food Funct 2018; 8:3636-3646. [PMID: 28905953 DOI: 10.1039/c7fo00495h] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The aim of this research was to investigate the antioxidant and anti-apoptotic activities of Potentilla anserina polysaccharide (PAP) on kidney damage induced by cadmium (Cd) in vitro and in vivo. PAP has been suggested to have anti-oxidation, anti-apoptosis, immunoregulation, antimicrobial, antitussive, and expectorant abilities. In this study, PAP was extracted and the major components of PAP were analyzed. It was shown that PAP pretreatment remarkably improved redox homeostasis, both in human embryonic kidney 293 (HEK293) cells and in BALB/c mice. Administration of PAP attenuated the mitochondrial dysfunction, degeneration, and fibrosis of kidney induced by Cd. Furthermore, PAP exhibited anti-apoptotic activity, which involved regulating both the mitochondria-mediated intrinsic apoptotic pathway and the death receptor-initiated extrinsic pathway. These results suggest that PAP is a potential therapeutic agent for Cd-induced nephrotoxicity.
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Affiliation(s)
- Rong Shen
- Institute of Integrated Traditional Chinese and Western Medicine, School of Basic Medical Sciences, Lanzhou University, Lanzhou, 730000, Gansu, China.
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Age-Related Macular Degeneration: New Paradigms for Treatment and Management of AMD. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:8374647. [PMID: 29484106 PMCID: PMC5816845 DOI: 10.1155/2018/8374647] [Citation(s) in RCA: 143] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Accepted: 12/06/2017] [Indexed: 12/03/2022]
Abstract
Age-related macular degeneration (AMD) is a well-characterized and extensively studied disease. It is currently considered the leading cause of visual disability among patients over 60 years. The hallmark of early AMD is the formation of drusen, pigmentary changes at the macula, and mild to moderate vision loss. There are two forms of AMD: the “dry” and the “wet” form that is less frequent but is responsible for 90% of acute blindness due to AMD. Risk factors have been associated with AMD progression, and they are taking relevance to understand how AMD develops: (1) advanced age and the exposition to environmental factors inducing high levels of oxidative stress damaging the macula and (2) this damage, which causes inflammation inducing a vicious cycle, altogether causing central vision loss. There is neither a cure nor treatment to prevent AMD. However, there are some treatments available for the wet form of AMD. This article will review some molecular and cellular mechanisms associated with the onset of AMD focusing on feasible treatments for each related factor in the development of this pathology such as vascular endothelial growth factor, oxidative stress, failure of the clearance of proteins and organelles, and glial cell dysfunction in AMD.
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Kawami M, Deguchi J, Yumoto R, Sakakibara N, Tsukamoto I, Konishi R, Takano M. Effect of COA-Cl on transforming growth factor-β1-induced epithelial–mesenchymal transition in RLE/Abca3 cells. Drug Metab Pharmacokinet 2017; 32:224-227. [DOI: 10.1016/j.dmpk.2017.05.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 04/19/2017] [Accepted: 05/09/2017] [Indexed: 01/15/2023]
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Feng L, Ju M, Lee KYV, Mackey A, Evangelista M, Iwata D, Adamson P, Lashkari K, Foxton R, Shima D, Ng YS. A Proinflammatory Function of Toll-Like Receptor 2 in the Retinal Pigment Epithelium as a Novel Target for Reducing Choroidal Neovascularization in Age-Related Macular Degeneration. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 187:2208-2221. [PMID: 28739342 DOI: 10.1016/j.ajpath.2017.06.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 05/16/2017] [Accepted: 06/08/2017] [Indexed: 11/28/2022]
Abstract
Current treatments for choroidal neovascularization, a major cause of blindness for patients with age-related macular degeneration, treat symptoms but not the underlying causes of the disease. Inflammation has been strongly implicated in the pathogenesis of choroidal neovascularization. We examined the inflammatory role of Toll-like receptor 2 (TLR2) in age-related macular degeneration. TLR2 was robustly expressed by the retinal pigment epithelium in mouse and human eyes, both normal and with macular degeneration/choroidal neovascularization. Nuclear localization of NF-κB, a major downstream target of TLR2 signaling, was detected in the retinal pigment epithelium of human eyes, particularly in eyes with advanced stages of age-related macular degeneration. TLR2 antagonism effectively suppressed initiation and growth of spontaneous choroidal neovascularization in a mouse model, and the combination of anti-TLR2 and antivascular endothelial growth factor receptor 2 yielded an additive therapeutic effect on both area and number of spontaneous choroidal neovascularization lesions. Finally, in primary human fetal retinal pigment epithelium cells, ligand binding to TLR2 induced robust expression of proinflammatory cytokines, and end products of lipid oxidation had a synergistic effect on TLR2 activation. Our data illustrate a functional role for TLR2 in the pathogenesis of choroidal neovascularization, likely by promoting inflammation of the retinal pigment epithelium, and validate TLR2 as a novel therapeutic target for reducing choroidal neovascularization.
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Affiliation(s)
- Lili Feng
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - Meihua Ju
- University College of London Institute of Ophthalmology, London, United Kingdom; Department of Ocular Biology and Therapeutics, University College of London Institute of Ophthalmology, London, United Kingdom
| | - Kei Ying V Lee
- University College of London Institute of Ophthalmology, London, United Kingdom; Department of Ocular Biology and Therapeutics, University College of London Institute of Ophthalmology, London, United Kingdom
| | - Ashley Mackey
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - Mariasilvia Evangelista
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - Daiju Iwata
- University College of London Institute of Ophthalmology, London, United Kingdom; Department of Ocular Biology and Therapeutics, University College of London Institute of Ophthalmology, London, United Kingdom
| | - Peter Adamson
- University College of London Institute of Ophthalmology, London, United Kingdom
| | - Kameran Lashkari
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - Richard Foxton
- University College of London Institute of Ophthalmology, London, United Kingdom; Department of Ocular Biology and Therapeutics, University College of London Institute of Ophthalmology, London, United Kingdom
| | - David Shima
- University College of London Institute of Ophthalmology, London, United Kingdom; Department of Ocular Biology and Therapeutics, University College of London Institute of Ophthalmology, London, United Kingdom
| | - Yin Shan Ng
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts.
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64
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Ferrington DA, Ebeling MC, Kapphahn RJ, Terluk MR, Fisher CR, Polanco JR, Roehrich H, Leary MM, Geng Z, Dutton JR, Montezuma SR. Altered bioenergetics and enhanced resistance to oxidative stress in human retinal pigment epithelial cells from donors with age-related macular degeneration. Redox Biol 2017; 13:255-265. [PMID: 28600982 PMCID: PMC5466586 DOI: 10.1016/j.redox.2017.05.015] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 05/23/2017] [Indexed: 01/03/2023] Open
Abstract
Age-related macular degeneration (AMD) is the leading cause of blindness among older adults. It has been suggested that mitochondrial defects in the retinal pigment epithelium (RPE) underlies AMD pathology. To test this idea, we developed primary cultures of RPE to ask whether RPE from donors with AMD differ in their metabolic profile compared with healthy age-matched donors. Analysis of gene expression, protein content, and RPE function showed that these cultured cells replicated many of the cardinal features of RPE in vivo. Using the Seahorse Extracellular Flux Analyzer to measure bioenergetics, we observed RPE from donors with AMD exhibited reduced mitochondrial and glycolytic function compared with healthy donors. RPE from AMD donors were also more resistant to oxidative inactivation of these two energy-producing pathways and were less susceptible to oxidation-induced cell death compared with cells from healthy donors. Investigation of the potential mechanism responsible for differences in bioenergetics and resistance to oxidative stress showed RPE from AMD donors had increased PGC1α protein as well as differential expression of multiple genes in response to an oxidative challenge. Based on our data, we propose that cultured RPE from donors phenotyped for the presence or absence of AMD provides an excellent model system for studying "AMD in a dish". Our results are consistent with the ideas that (i) a bioenergetics crisis in the RPE contributes to AMD pathology, and (ii) the diseased environment in vivo causes changes in the cellular profile that are retained in vitro.
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Affiliation(s)
- Deborah A. Ferrington
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA,Graduate Program in Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA,Corresponding author at: 380 Lions Research Bldg., 2001 6th St. SE, Minneapolis, MN 55455, USA.
| | - Mara C. Ebeling
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA
| | - Rebecca J. Kapphahn
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA
| | - Marcia R. Terluk
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA
| | - Cody R. Fisher
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA,Graduate Program in Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Jorge R. Polanco
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA
| | - Heidi Roehrich
- Histology Core for Vision Research, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Michaela M. Leary
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA
| | - Zhaohui Geng
- Stem Cell Institute and Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA.
| | - James R. Dutton
- Stem Cell Institute and Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Sandra R. Montezuma
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA
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65
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Jiang S, Teague AM, Tryggestad JB, Chernausek SD. Role of microRNA-130b in placental PGC-1α/TFAM mitochondrial biogenesis pathway. Biochem Biophys Res Commun 2017; 487:607-612. [PMID: 28433632 DOI: 10.1016/j.bbrc.2017.04.099] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 04/18/2017] [Indexed: 11/30/2022]
Abstract
Diabetes during pregnancy is associated with abnormal placenta mitochondrial function and increased oxidative stress, which affect fetal development and offspring long-term health. Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) is a master regulator of mitochondrial biogenesis and energy metabolism. The molecular mechanisms underlying the regulation of PGC-1α in placenta in the context of diabetes remain unclear. The present study examined the role of microRNA 130b (miR-130b-3p) in regulating PGC-1α expression and oxidative stress in a placental trophoblastic cell line (BeWo). Prolonged exposure of BeWo cells to high glucose mimicking hyperglycemia resulted in decreased protein abundance of PGC-1α and its downstream factor, mitochondrial transcription factor A (TFAM). High glucose treatment increased the expression of miR-130b-3p in BeWo cells, as well as exosomal secretion of miR-130b-3p. Transfection of BeWo cells with miR-130b-3p mimic reduced the abundance of PGC-1α, whereas inhibition of miR-130b-3p increased PGC-1α expression in response to high glucose, suggesting a role for miR-130b-3p in mediating high glucose-induced down regulation of PGC-1α expression. In addition, miR-130b-3p anti-sense inhibitor increased TFAM expression and reduced 4-hydroxynonenal (4-HNE)-induced production of reactive oxygen species (ROS). Taken together, these findings reveal that miR-130b-3p down-regulates PGC-1α expression in placental trophoblasts, and inhibition of miR-130b-3p appears to improve mitochondrial biogenesis signaling and protect placental trophoblast cells from oxidative stress.
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Affiliation(s)
- Shaoning Jiang
- Department of Pediatrics, Section of Diabetes and Endocrinology, Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
| | - April M Teague
- Department of Pediatrics, Section of Diabetes and Endocrinology, Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Jeanie B Tryggestad
- Department of Pediatrics, Section of Diabetes and Endocrinology, Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Steven D Chernausek
- Department of Pediatrics, Section of Diabetes and Endocrinology, Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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Spencer C, Abend S, McHugh KJ, Saint-Geniez M. Identification of a synergistic interaction between endothelial cells and retinal pigment epithelium. J Cell Mol Med 2017; 21:2542-2552. [PMID: 28402065 PMCID: PMC5618686 DOI: 10.1111/jcmm.13175] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 02/17/2017] [Indexed: 12/11/2022] Open
Abstract
The retinal pigment epithelium located between the neurosensory retina and the choroidal vasculature is critical for the function and maintenance of both the photoreceptors and underlying capillary endothelium. While the trophic role of retinal pigment epithelium on choroidal endothelial cells is well recognized, the existence of a reciprocal regulatory function of endothelial cells on retinal pigment epithelium cells remained to be fully characterized. Using a physiological long‐term co‐culture system, we determined the effect of retinal pigment epithelium‐endothelial cell heterotypic interactions on cell survival, behaviour and matrix deposition. Human retinal pigment epithelium and endothelial cells were cultured on opposite sides of polyester transwells for up to 4 weeks in low serum conditions. Cell viability was quantified using a trypan blue assay. Cellular morphology was evaluated by H&E staining, S.E.M. and immunohistochemistry. Retinal pigment epithelium phagocytic function was examined using a fluorescent bead assay. Gene expression analysis was performed on both retinal pigment epithelium and endothelial cells by quantitative PCR. Quantification of extracellular matrix deposition was performed on decellularized transwells stained for collagen IV, fibronectin and fibrillin. Our results showed that presence of endothelial cells significantly improves retinal pigment epithelium maturation and function as indicated by the induction of visual cycle‐associated genes, accumulation of a Bruch's membrane‐like matrix and increase in retinal pigment epithelium phagocytic activity. Co‐culture conditions led to increased expression of anti‐angiogenic growth factors and receptors in both retinal pigment epithelium and endothelial cells compared to monoculture. Tube‐formation assays confirmed that co‐culture with retinal pigment epithelium significantly decreased the angiogenic phenotype of endothelial cells. These findings provide evidence of critical interdependent interactions between retinal pigment epithelium and endothelial cell involved in the maintenance of retinal homeostasis.
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Affiliation(s)
- Carrie Spencer
- Schepens Eye Research Institute, Mass. Eye and Ear, Boston, MA, USA
| | - Stephanie Abend
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Kevin J McHugh
- Schepens Eye Research Institute, Mass. Eye and Ear, Boston, MA, USA.,Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Magali Saint-Geniez
- Schepens Eye Research Institute, Mass. Eye and Ear, Boston, MA, USA.,Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
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Golestaneh N, Chu Y, Cheng SK, Cao H, Poliakov E, Berinstein DM. Repressed SIRT1/PGC-1α pathway and mitochondrial disintegration in iPSC-derived RPE disease model of age-related macular degeneration. J Transl Med 2016; 14:344. [PMID: 27998274 PMCID: PMC5175395 DOI: 10.1186/s12967-016-1101-8] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 11/29/2016] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Study of age related macular degeneration (AMD) has been hampered by lack of human models that represent the complexity of the disease. Here we have developed a human in vitro disease model of AMD to investigate the underlying AMD disease mechanisms. METHODS Generation of iPSCs from retinal pigment epithelium (RPE) of AMD donors, age-matched normal donors, skin fibroblasts of a dry AMD patient, and differentiation of iPSCs into RPE (AMD RPE-iPSC-RPE, normal RPE-iPSC-RPE and AMD Skin-iPSC-RPE, respectively). Immunostaining, cell viability assay and reactive oxygen species (ROS) production under oxidative stress conditions, electron microscopy (EM) imaging, ATP production and glycogen concentration assays, quantitative real time PCR, western blot, karyotyping. RESULTS The AMD RPE-iPSC-RPE and AMD Skin-iPSC-RPE present functional impairment and exhibit distinct disease phenotypes compared to RPE-iPSC-RPE generated from normal donors (Normal RPE-iPSC-RPE). The AMD RPE-iPSC-RPE and AMD Skin-iPSC-RPE show increased susceptibility to oxidative stress and produced higher levels of reactive oxygen species (ROS) under stress in accordance with recent reports. The susceptibility to oxidative stress-induced cell death in AMD RPE-iPSC-RPE and Skin-iPSC-RPE was consistent with inability of the AMD RPE-iPSC-RPE and Skin-iPSC-RPE to increase SOD2 expression under oxidative stress. Phenotypic analysis revealed disintegrated mitochondria, accumulation of autophagosomes and lipid droplets in AMD RPE-iPSC-RPE and AMD Skin-iPSC-RPE. Mitochondrial activity was significantly lower in AMD RPE-iPSC-RPE and AMD Skin-iPSC-RPE compared to normal cells and glycogen concentration was significantly increased in the diseased cells. Furthermore, Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), a regulator of mitochondrial biogenesis and function was repressed, and lower expression levels of NAD-dependent deacetylase sirtuin1 (SIRT1) were found in AMD RPE-iPSC-RPE and AMD Skin-iPSC-RPE as compared to normal RPE-iPSC-RPE. CONCLUSIONS Our studies suggest SIRT1/PGC-1α as underlying pathways contributing to AMD pathophysiology, and open new avenues for development of targeted drugs for treatment of this devastating neurodegenerative disease of the visual system.
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Affiliation(s)
- Nady Golestaneh
- Department of Ophthalmology, Georgetown University Medical Center, 3900 Reservoir Road NW, Medical-Dental Building, Room NE203, Washington, DC 20057 USA
- Department of Neurology, Georgetown University Medical Center, Washington, DC USA
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington, DC USA
| | - Yi Chu
- Department of Ophthalmology, Georgetown University Medical Center, 3900 Reservoir Road NW, Medical-Dental Building, Room NE203, Washington, DC 20057 USA
| | - Shuk Kei Cheng
- Department of Ophthalmology, Georgetown University Medical Center, 3900 Reservoir Road NW, Medical-Dental Building, Room NE203, Washington, DC 20057 USA
| | - Hong Cao
- Department of Ophthalmology, Georgetown University Medical Center, 3900 Reservoir Road NW, Medical-Dental Building, Room NE203, Washington, DC 20057 USA
| | - Eugenia Poliakov
- Retinal Cell and Molecular Biology (LRCMB), National Eye Institute, National Institutes of Health, Bethesda, MD USA
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68
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Reductive carboxylation is a major metabolic pathway in the retinal pigment epithelium. Proc Natl Acad Sci U S A 2016; 113:14710-14715. [PMID: 27911769 DOI: 10.1073/pnas.1604572113] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The retinal pigment epithelium (RPE) is a monolayer of pigmented cells that requires an active metabolism to maintain outer retinal homeostasis and compensate for oxidative stress. Using 13C metabolic flux analysis in human RPE cells, we found that RPE has an exceptionally high capacity for reductive carboxylation, a metabolic pathway that has recently garnered significant interest because of its role in cancer cell survival. The capacity for reductive carboxylation in RPE exceeds that of all other cells tested, including retina, neural tissue, glial cells, and a cancer cell line. Loss of reductive carboxylation disrupts redox balance and increases RPE sensitivity to oxidative damage, suggesting that deficiencies of reductive carboxylation may contribute to RPE cell death. Supporting reductive carboxylation by supplementation with an NAD+ precursor or its substrate α-ketoglutarate or treatment with a poly(ADP ribose) polymerase inhibitor protects reductive carboxylation and RPE viability from excessive oxidative stress. The ability of these treatments to rescue RPE could be the basis for an effective strategy to treat blinding diseases caused by RPE dysfunction.
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