1
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O'Neill HC, Limnios IJ, Barnett NL. Advancing a Stem Cell Therapy for Age-Related Macular Degeneration. Curr Stem Cell Res Ther 2020; 15:89-97. [PMID: 31854278 DOI: 10.2174/1574888x15666191218094020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 11/08/2019] [Accepted: 11/25/2019] [Indexed: 01/01/2023]
Abstract
The retinal pigment epithelium (RPE) is a multifunctional monolayer located at the back of the eye required for the survival and function of the light-sensing photoreceptors. In Age-related Macular Degeneration (AMD), the loss of RPE cells leads to photoreceptor death and permanent blindness. RPE cell transplantation aims to halt or reverse vision loss by preventing the death of photoreceptor cells and is considered one of the most viable applications of stem cell therapy in the field of regenerative medicine. Proof-of-concept of RPE cell transplantation for treating retinal degenerative disease, such as AMD, has long been established in animal models and humans using primary RPE cells, while recent research has focused on the transplantation of RPE cells derived from human pluripotent stem cells (hPSC). Early results from clinical trials indicate that transplantation of hPSC-derived RPE cells is safe and can improve vision in AMD patients. Current hPSC-RPE cell production protocols used in clinical trials are nevertheless inefficient. Treatment of large numbers of AMD patients using stem cellderived products may be dependent on the ability to generate functional cells from multiple hPSC lines using robust and clinically-compliant methods. Transplantation outcomes may be improved by delivering RPE cells on a thin porous membrane for better integration into the retina, and by manipulation of the outcome through control of immune rejection and inflammatory responses.
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Affiliation(s)
- Helen C O'Neill
- Clem Jones Centre for Regenerative Medicine, Bond University, Gold Coast 4229, Queensland, Australia
| | - Ioannis J Limnios
- Clem Jones Centre for Regenerative Medicine, Bond University, Gold Coast 4229, Queensland, Australia
| | - Nigel L Barnett
- Clem Jones Centre for Regenerative Medicine, Bond University, Gold Coast 4229, Queensland, Australia
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2
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Zhou M, Weber SR, Zhao Y, Chen H, Barber AJ, Grillo SL, Wills CA, Wang HG, Hulleman JD, Sundstrom JM. Expression of R345W-Fibulin-3 Induces Epithelial-Mesenchymal Transition in Retinal Pigment Epithelial Cells. Front Cell Dev Biol 2020; 8:469. [PMID: 32637411 PMCID: PMC7317295 DOI: 10.3389/fcell.2020.00469] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 05/20/2020] [Indexed: 12/13/2022] Open
Abstract
Purpose To investigate the role of protein misfolding in retinal pigment epithelial (RPE) cell dysfunction, the effects of R345W-Fibulin-3 expression on RPE cell phenotype were studied. Methods Primary RPE cells were cultured to confluence on Transwells and infected with lentivirus constructs to express wild-type (WT)- or R345W-Fibulin-3. Barrier function was assessed by evaluating zonula occludens-1 (ZO-1) distribution and trans-epithelial electrical resistance (TER). Polarized secretion of vascular endothelial growth factor (VEGF), was measured by Enzyme-linked immunosorbent assay (ELISA). Differentiation status was assessed by qPCR of genes known to be preferentially expressed in terminally differentiated RPE cells, and conversion to an epithelial–mesenchymal transition (EMT) phenotype was assessed by a migration assay. Results Compared to RPE cells expressing WT-Fibulin-3, ZO-1 distribution was disrupted and TER values were significantly lower in RPE cells expressing R345W-Fibulin-3. In cells expressing mutant Fibulin-3, VEGF secretion was attenuated basally but not in the apical direction, whereas Fibulin-3 secretion was reduced in both the apical and basal directions. Retinal pigment epithelial signature genes were downregulated and multiple genes associated with EMT were upregulated in the mutant group. Migration assays revealed a faster recovery rate in ARPE-19 cells overexpressing R345W-Fibulin-3 compared to WT. Conclusions The results suggest that expression of R345W-Fibulin-3 promotes EMT in RPE cells.
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Affiliation(s)
- Mi Zhou
- Department of Ophthalmology, Penn State Hershey College of Medicine, Hershey, PA, United States
| | - Sarah R Weber
- Department of Ophthalmology, Penn State Hershey College of Medicine, Hershey, PA, United States
| | - Yuanjun Zhao
- Department of Ophthalmology, Penn State Hershey College of Medicine, Hershey, PA, United States
| | - Han Chen
- TEM Facility, Penn State Hershey College of Medicine, Hershey, PA, United States
| | - Alistair J Barber
- Department of Ophthalmology, Penn State Hershey College of Medicine, Hershey, PA, United States
| | - Stephanie L Grillo
- Department of Ophthalmology, Penn State Hershey College of Medicine, Hershey, PA, United States
| | - Carson A Wills
- Division of Hematology and Oncology, Department of Pediatrics, Penn State Hershey College of Medicine, Hershey, PA, United States
| | - Hong Gang Wang
- Division of Hematology and Oncology, Department of Pediatrics, Penn State Hershey College of Medicine, Hershey, PA, United States
| | - John D Hulleman
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, United States
| | - Jeffrey M Sundstrom
- Department of Ophthalmology, Penn State Hershey College of Medicine, Hershey, PA, United States
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3
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Zhang C, Miyagishima KJ, Dong L, Rising A, Nimmagadda M, Liang G, Sharma R, Dejene R, Wang Y, Abu-Asab M, Qian H, Li Y, Kopera M, Maminishkis A, Martinez J, Miller S. Regulation of phagolysosomal activity by miR-204 critically influences structure and function of retinal pigment epithelium/retina. Hum Mol Genet 2020; 28:3355-3368. [PMID: 31332443 DOI: 10.1093/hmg/ddz171] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 07/04/2019] [Accepted: 07/09/2019] [Indexed: 12/13/2022] Open
Abstract
MicroRNA-204 (miR-204) is expressed in pulmonary, renal, mammary and eye tissue, and its reduction can result in multiple diseases including cancer. We first generated miR-204-/- mice to study the impact of miR-204 loss on retinal and retinal pigment epithelium (RPE) structure and function. The RPE is fundamentally important for maintaining the health and integrity of the retinal photoreceptors. miR-204-/- eyes evidenced areas of hyper-autofluorescence and defective photoreceptor digestion, along with increased microglia migration to the RPE. Migratory Iba1+ microglial cells were localized to the RPE apical surface where they participated in the phagocytosis of photoreceptor outer segments (POSs) and contributed to a persistent build-up of rhodopsin. These structural, molecular and cellular outcomes were accompanied by decreased light-evoked electrical responses from the retina and RPE. In parallel experiments, we suppressed miR-204 expression in primary cultures of human RPE using anti-miR-204. In vitro suppression of miR-204 in human RPE similarly showed abnormal POS clearance and altered expression of autophagy-related proteins and Rab22a, a regulator of endosome maturation. Together, these in vitro and in vivo experiments suggest that the normally high levels of miR-204 in RPE can mitigate disease onset by preventing generation of oxidative stress and inflammation originating from intracellular accumulation of undigested photoreactive POS lipids. More generally, these results implicate RPE miR-204-mediated regulation of autophagy and endolysosomal interaction as a critical determinant of normal RPE/retina structure and function.
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Affiliation(s)
- Congxiao Zhang
- Ophthalmic Genetics and Visual Function Branch, Section on Epithelial and Retinal Physiology and Disease, National Eye Institute, National Institutes of Health, Bethesda, MD USA
| | - Kiyoharu J Miyagishima
- Ophthalmic Genetics and Visual Function Branch, Section on Epithelial and Retinal Physiology and Disease, National Eye Institute, National Institutes of Health, Bethesda, MD USA
| | - Lijin Dong
- Genetic Engineering Facility, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Aaron Rising
- Ophthalmic Genetics and Visual Function Branch, Unit on Ocular and Stem Cell Translational Research, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Malika Nimmagadda
- Ophthalmic Genetics and Visual Function Branch, Unit on Ocular and Stem Cell Translational Research, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Genqing Liang
- Ophthalmic Genetics and Visual Function Branch, Unit on Ocular and Stem Cell Translational Research, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Ruchi Sharma
- Ophthalmic Genetics and Visual Function Branch, Unit on Ocular and Stem Cell Translational Research, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Roba Dejene
- Ophthalmic Genetics and Visual Function Branch, Unit on Ocular and Stem Cell Translational Research, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Yuan Wang
- Ophthalmic Genetics and Visual Function Branch, Section on Epithelial and Retinal Physiology and Disease, National Eye Institute, National Institutes of Health, Bethesda, MD USA
| | - Mones Abu-Asab
- Section of Histopathology, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Haohua Qian
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Yichao Li
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Megan Kopera
- Genetic Engineering Facility, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Arvydas Maminishkis
- Ophthalmic Genetics and Visual Function Branch, Section on Epithelial and Retinal Physiology and Disease, National Eye Institute, National Institutes of Health, Bethesda, MD USA
| | - Jennifer Martinez
- Inflammation and Autoimmunity, National Institute of Environmental Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Sheldon Miller
- Ophthalmic Genetics and Visual Function Branch, Section on Epithelial and Retinal Physiology and Disease, National Eye Institute, National Institutes of Health, Bethesda, MD USA
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4
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Wang B, Wang L, Gu S, Yu Y, Huang H, Mo K, Xu H, Zeng F, Xiao Y, Peng L, Liu C, Cao N, Liu Y, Yuan J, Ouyang H. D609 protects retinal pigmented epithelium as a potential therapy for age-related macular degeneration. Signal Transduct Target Ther 2020; 5:20. [PMID: 32296021 PMCID: PMC7054264 DOI: 10.1038/s41392-020-0122-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 01/06/2020] [Accepted: 01/13/2020] [Indexed: 12/19/2022] Open
Abstract
Accumulated oxidative damage may lead to irreversible retinal pigmented epithelium (RPE) cell death, which is considered to be the primary cause of dry age-related macular degeneration (AMD), leading to blindness in the elderly. However, an effective therapy for this disease is lacking. Here, we described a robust high-content screening procedure with a library of 814 protective compounds and found that D609 strongly protected RPE cells from sodium iodate (SI)-induced oxidative cell death and prolonged their healthy survival. D609 effectively attenuated excessive reactive oxygen species (ROS) and prevented severe mitochondrial loss due to oxidative stress in the RPE cells. Surprisingly, the potent antioxidative effects of D609 were not achieved through its own reducibility but were primarily dependent on its ability to increase the expression of metallothionein. The injection of this small water-soluble molecule also showed an explicit protective effect of the RPE layer in an SI-induced AMD mouse model. These findings suggested that D609 could serve as a novel antioxidative protector of RPE cells both in vitro and in vivo and unveiled a novel antioxidative mechanism of D609, which may ultimately have clinical applications for the treatment of AMD.
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Affiliation(s)
- Bowen Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510623, China
| | - Li Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510623, China
| | - Sijie Gu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510623, China
| | - Yankun Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510623, China
| | - Huaxing Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510623, China
| | - Kunlun Mo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510623, China
| | - He Xu
- Program of Stem Cells and Regenerative Medicine, Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangdong, 510080, China
| | - Fanzhu Zeng
- Program of Stem Cells and Regenerative Medicine, Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangdong, 510080, China
| | - Yichen Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510623, China
| | - Lulu Peng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510623, China
| | - Chunqiao Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510623, China
| | - Nan Cao
- Program of Stem Cells and Regenerative Medicine, Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangdong, 510080, China
| | - Yizhi Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510623, China.
| | - Jin Yuan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510623, China.
| | - Hong Ouyang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510623, China.
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5
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Meyer JG, Garcia TY, Schilling B, Gibson BW, Lamba DA. Proteome and Secretome Dynamics of Human Retinal Pigment Epithelium in Response to Reactive Oxygen Species. Sci Rep 2019; 9:15440. [PMID: 31659173 PMCID: PMC6817852 DOI: 10.1038/s41598-019-51777-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 10/04/2019] [Indexed: 12/22/2022] Open
Abstract
Age-related macular degeneration (AMD) is the leading cause of blindness in developed countries, and is characterized by slow retinal degeneration linked to chronic reactive oxygen species (ROS) in the retinal pigmented epithelium (RPE). The molecular mechanisms leading to RPE dysfunction in response to ROS are unclear. Here, human stem cell-derived RPE samples were stressed with ROS for 1 or 3 weeks, and both intracellular and secreted proteomes were quantified by mass spectrometry. ROS increased glycolytic proteins but decreased mitochondrial complex I subunits, as well as membrane proteins required for endocytosis. RPE secreted over 1,000 proteins, many of which changed significantly due to ROS. Notably, secreted APOE is decreased 4-fold, and urotensin-II, the strongest known vasoconstrictor, doubled. Furthermore, secreted TGF-beta is increased, and its cognate signaler BMP1 decreased in the secretome. Together, our results paint a detailed molecular picture of the retinal stress response in space and time.
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Affiliation(s)
- Jesse G Meyer
- Buck Institute for Research on Aging, Novato, CA, 94945, USA.
- Department of Chemistry, Department of Biomolecular Chemistry, National Center for Quantitative Biology of Complex Systems, University of Wisconsin - Madison, Madison, WI, 53706, USA.
| | - Thelma Y Garcia
- Buck Institute for Research on Aging, Novato, CA, 94945, USA
| | | | - Bradford W Gibson
- Buck Institute for Research on Aging, Novato, CA, 94945, USA
- Discovery Attribute Sciences, Research, Amgen, South San Francisco, CA, 94080, USA
| | - Deepak A Lamba
- Buck Institute for Research on Aging, Novato, CA, 94945, USA.
- Department of Ophthalmology, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California - San Francisco, San Francisco, CA, 94143, USA.
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6
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Hu X, Calton MA, Tang S, Vollrath D. Depletion of Mitochondrial DNA in Differentiated Retinal Pigment Epithelial Cells. Sci Rep 2019; 9:15355. [PMID: 31653972 PMCID: PMC6814719 DOI: 10.1038/s41598-019-51761-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 09/26/2019] [Indexed: 11/17/2022] Open
Abstract
We investigated the effects of treating differentiated retinal pigment epithelial (RPE) cells with didanosine (ddI), which is associated with retinopathy in individuals with HIV/AIDS. We hypothesized that such treatment would cause depletion of mitochondrial DNA and provide insight into the consequences of degradation of RPE mitochondrial function in aging and disease. Treatment of differentiated ARPE-19 or human primary RPE cells with 200 µM ddI for 6–24 days was not cytotoxic but caused up to 60% depletion of mitochondrial DNA, and a similar reduction in mitochondrial membrane potential and NDUFA9 protein abundance. Mitochondrial DNA-depleted RPE cells demonstrated enhanced aerobic glycolysis by extracellular flux analysis, increased AMP kinase activation, reduced mTOR activity, and increased resistance to cell death in response to treatment with the oxidant, sodium iodate. We conclude that ddI-mediated mitochondrial DNA depletion promotes a glycolytic shift in differentiated RPE cells and enhances resistance to oxidative damage. Our use of ddI treatment to induce progressive depletion of mitochondrial DNA in differentiated human RPE cells should be widely applicable for other studies aimed at understanding RPE mitochondrial dysfunction in aging and disease.
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Affiliation(s)
- Xinqian Hu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China. .,Department of Genetics, Stanford University School of Medicine, Stanford, CA, 94305, USA.
| | - Melissa A Calton
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Shibo Tang
- AIER School of Ophthalmology, Central South University, Changsha, China.,AIER Eye Institute, Changsha, China.,CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Douglas Vollrath
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, 94305, USA
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7
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Chauhan R, Balgemann R, Greb C, Nunn BM, Ueda S, Noma H, McDonald K, Kaplan HJ, Tamiya S, O'Toole MG. Production of dasatinib encapsulated spray-dried poly (lactic-co-glycolic acid) particles. J Drug Deliv Sci Technol 2019. [DOI: 10.1016/j.jddst.2019.101204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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8
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Jung H, Liu J, Liu T, George A, Smelkinson MG, Cohen S, Sharma R, Schwartz O, Maminishkis A, Bharti K, Cukras C, Huryn LA, Brooks BP, Fariss R, Tam J. Longitudinal adaptive optics fluorescence microscopy reveals cellular mosaicism in patients. JCI Insight 2019; 4:124904. [PMID: 30895942 DOI: 10.1172/jci.insight.124904] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 02/12/2019] [Indexed: 12/22/2022] Open
Abstract
The heterogeneity of individual cells in a tissue has been well characterized, largely using ex vivo approaches that do not permit longitudinal assessments of the same tissue over long periods of time. We demonstrate a potentially novel application of adaptive optics fluorescence microscopy to visualize and track the in situ mosaicism of retinal pigment epithelial (RPE) cells directly in the human eye. After a short, dynamic period during which RPE cells take up i.v.-administered indocyanine green (ICG) dye, we observed a remarkably stable heterogeneity in the fluorescent pattern that gradually disappeared over a period of days. This pattern could be robustly reproduced with a new injection and follow-up imaging in the same eye out to at least 12 months, which enabled longitudinal tracking of RPE cells. Investigation of ICG uptake in primary human RPE cells and in a mouse model of ICG uptake alongside human imaging corroborated our findings that the observed mosaicism is an intrinsic property of the RPE tissue. We demonstrate a potentially novel application of fluorescence microscopy to detect subclinical changes to the RPE, a technical advance that has direct implications for improving our understanding of diseases such as oculocutaneous albinism, late-onset retinal degeneration, and Bietti crystalline dystrophy.
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Affiliation(s)
- HaeWon Jung
- National Eye Institute, NIH, Bethesda, Maryland, USA
| | - Jianfei Liu
- National Eye Institute, NIH, Bethesda, Maryland, USA
| | - Tao Liu
- National Eye Institute, NIH, Bethesda, Maryland, USA
| | - Aman George
- National Eye Institute, NIH, Bethesda, Maryland, USA
| | - Margery G Smelkinson
- National Institute of Allergy and Infectious Disease, Research Technologies Branch, NIH, Bethesda, Maryland, USA
| | - Sarah Cohen
- University of North Carolina - Chapel Hill, Chapel Hill, North Carolina, USA
| | - Ruchi Sharma
- National Eye Institute, NIH, Bethesda, Maryland, USA
| | - Owen Schwartz
- National Institute of Allergy and Infectious Disease, Research Technologies Branch, NIH, Bethesda, Maryland, USA
| | | | - Kapil Bharti
- National Eye Institute, NIH, Bethesda, Maryland, USA
| | | | | | | | - Robert Fariss
- National Eye Institute, NIH, Bethesda, Maryland, USA
| | - Johnny Tam
- National Eye Institute, NIH, Bethesda, Maryland, USA
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9
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Fernandez-Godino R, Bujakowska KM, Pierce EA. Changes in extracellular matrix cause RPE cells to make basal deposits and activate the alternative complement pathway. Hum Mol Genet 2019; 27:147-159. [PMID: 29095988 DOI: 10.1093/hmg/ddx392] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/25/2017] [Indexed: 01/13/2023] Open
Abstract
The design of efficient therapies for age-related macular degeneration (AMD) is limited by our understanding of the pathogenesis of basal deposits, which form between retinal pigment epithelium (RPE) and Bruch's membrane (BrM) early in disease, and involve activation of the complement system. To investigate the roles of BrM, RPE and complement in an AMD, we generated abnormal extracellular matrix (ECM) using CRISPR-edited ARPE-19 cells. We introduced to these cells the p.R345W mutation in EFEMP1, which causes early-onset macular degeneration. The abnormal ECM binds active complement C3 and causes the formation of basal deposits by normal human fetal (hf)RPE cells. Human fetal RPE (hfRPE) cells grown on abnormal ECM or BrM explants from AMD donors show chronic activation of the alternative complement pathway by excessive deposition of C3b. This process is exacerbated by impaired ECM turnover via increased matrix metalloproteinase-2 activity. The local cleavage of C3 via convertase-independent mechanisms can be a new therapeutic target for early AMD.
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Affiliation(s)
- Rosario Fernandez-Godino
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Ocular Genomics Institute, Boston, MA 02114, USA.,Harvard Medical School, Boston, MA 02114, USA
| | - Kinga M Bujakowska
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Ocular Genomics Institute, Boston, MA 02114, USA.,Harvard Medical School, Boston, MA 02114, USA
| | - Eric A Pierce
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Ocular Genomics Institute, Boston, MA 02114, USA.,Harvard Medical School, Boston, MA 02114, USA
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10
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Brown CN, Green BD, Thompson RB, den Hollander AI, Lengyel I. Metabolomics and Age-Related Macular Degeneration. Metabolites 2018; 9:metabo9010004. [PMID: 30591665 PMCID: PMC6358913 DOI: 10.3390/metabo9010004] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 12/17/2018] [Accepted: 12/20/2018] [Indexed: 12/11/2022] Open
Abstract
Age-related macular degeneration (AMD) leads to irreversible visual loss, therefore, early intervention is desirable, but due to its multifactorial nature, diagnosis of early disease might be challenging. Identification of early markers for disease development and progression is key for disease diagnosis. Suitable biomarkers can potentially provide opportunities for clinical intervention at a stage of the disease when irreversible changes are yet to take place. One of the most metabolically active tissues in the human body is the retina, making the use of hypothesis-free techniques, like metabolomics, to measure molecular changes in AMD appealing. Indeed, there is increasing evidence that metabolic dysfunction has an important role in the development and progression of AMD. Therefore, metabolomics appears to be an appropriate platform to investigate disease-associated biomarkers. In this review, we explored what is known about metabolic changes in the retina, in conjunction with the emerging literature in AMD metabolomics research. Methods for metabolic biomarker identification in the eye have also been discussed, including the use of tears, vitreous, and aqueous humor, as well as imaging methods, like fluorescence lifetime imaging, that could be translated into a clinical diagnostic tool with molecular level resolution.
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Affiliation(s)
- Connor N Brown
- Wellcome-Wolfson Institute for Experimental Medicine (WWIEM), Queen's University Belfast, Belfast BT9 7BL, UK.
| | - Brian D Green
- Institute for Global Food Security (IGFS), Queen's University Belfast, Belfast BT9 6AG, UK.
| | - Richard B Thompson
- Department of Biochemistry and Molecular Biology, School of Medicine, University of Maryland, Baltimore, MD 21201, USA.
| | - Anneke I den Hollander
- Department of Ophthalmology, Radboud University Nijmegen Medical Centre, Nijmegen 6525 EX, The Netherlands.
| | - Imre Lengyel
- Wellcome-Wolfson Institute for Experimental Medicine (WWIEM), Queen's University Belfast, Belfast BT9 7BL, UK.
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11
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Fernandez-Godino R, Pierce EA. C3a triggers formation of sub-retinal pigment epithelium deposits via the ubiquitin proteasome pathway. Sci Rep 2018; 8:9679. [PMID: 29946065 PMCID: PMC6018664 DOI: 10.1038/s41598-018-28143-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Accepted: 06/15/2018] [Indexed: 01/25/2023] Open
Abstract
The mechanisms that connect complement system activation and basal deposit formation in early stages of age-related macular degeneration (AMD) are insufficiently understood, which complicates the design of efficient therapies to prevent disease progression. Using human fetal (hf) retinal pigment epithelial (RPE) cells, we have established an in vitro model to investigate the effect of complement C3a on RPE cells and its role in the formation of sub-RPE deposits. The results of these studies revealed that C3a produced after C3 activation is sufficient to induce the formation of sub-RPE deposits via complement-driven proteasome inhibition. C3a binds the C3a receptor (C3aR), stimulates deposition of collagens IV and VI underneath the RPE, and impairs the extracellular matrix (ECM) turnover by increased MMP-2 activity, all mediated by downregulation of the ubiquitin proteasome pathway (UPP). The formation of basal deposits can be prevented by the addition of a C3aR antagonist, which restores the UPP activity and ECM turnover. These findings indicate that the cell-based model can be used to test potential therapeutic agents in vitro. The data suggest that modulation of C3aR-mediated events could be a therapeutic approach for treatment of early AMD.
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Affiliation(s)
- Rosario Fernandez-Godino
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, 02114, USA.
| | - Eric A Pierce
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, 02114, USA
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12
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Method for measuring extracellular flux from intact polarized epithelial monolayers. Mol Vis 2018; 24:425-433. [PMID: 30034209 PMCID: PMC6031101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 06/23/2018] [Indexed: 12/03/2022] Open
Abstract
PURPOSE The Seahorse XFp platform is widely used for metabolic assessment of cultured cells. Current methods require replating of cells into specialized plates. This is problematic for certain cell types, such as primary human fetal RPE (hfRPE) cells, which must be cultured for months to become properly differentiated. Our goal was to overcome this limitation by devising a method for assaying intact cell monolayers with the Seahorse XFp, without the need for replating. METHODS Primary hfRPE cells were differentiated by prolonged culture on filter inserts. Triangular sections of filters with differentiated cells attached were excised, transferred to XFp cell culture miniplate wells, immobilized at the bottoms, and subjected to mitochondrial stress tests. Replated cells were measured for comparison. Differentiated hfRPE cells were challenged or not with bovine photoreceptor outer segments (POS), and mitochondrial stress tests were performed 3.5 h later, after filter excision and transfer to assay plates. RESULTS Differentiated hfRPE cells assayed following filter excision demonstrated increased maximal respiration, increased spare respiration capacity, and increased extracellular acidification rate (ECAR) relative to replated controls. hfRPE cells challenged with POS exhibited increased maximal respiration and spare capacity, with no apparent change in the ECAR, relative to untreated controls. CONCLUSIONS We have developed a method to reproducibly assay intact, polarized monolayers of hfRPE cells with the Seahorse XFp platform and have shown that the method yields more robust metabolic measurements compared to standard methods and is suitable for assessing the consequences of prolonged perturbations of differentiated cells. We expect our approach to be useful for a variety of studies involving metabolic assessment of adherent cells cultured on filters.
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Khristov V, Wan Q, Sharma R, Lotfi M, Maminishkis A, Bharti K. Polarized Human Retinal Pigment Epithelium Exhibits Distinct Surface Proteome on Apical and Basal Plasma Membranes. Methods Mol Biol 2018; 1722:223-247. [PMID: 29264809 DOI: 10.1007/978-1-4939-7553-2_15] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Surface proteins localized on the apical and basal plasma membranes are required for a cell to sense its environment and relay changes in ionic, cytokine, chemokine, and hormone levels to the inside of the cell. In a polarized cell, surface proteins are differentially localized on the apical or the basolateral sides of the cell. The retinal pigment epithelium (RPE) is an example of a polarized cell that performs a variety of functions that are dependent on its polarized state including trafficking of ions, fluid, and metabolites across the RPE monolayer. These functions are absolutely crucial for maintaining the health and integrity of adjacent photoreceptors, the photosensitive cells of the retina. Here we present a series of approaches to identify and validate the polarization state of cultured primary human RPE cells using immunostaining for RPE apical/basolateral markers, polarized cytokine secretion, electrophysiology, fluid transport, phagocytosis, and identification of plasma membrane proteins through cell surface capturing technology. These approaches are currently being used to validate the polarized state and the epithelial phenotype of human induced pluripotent stem (iPS) cell derived RPE cells. This work provides the basis for developing an autologous cell therapy for age-related macular degeneration using patient specific iPS cell derived RPE.
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Affiliation(s)
- Vladimir Khristov
- Section on Epithelial and Retinal Physiology and Disease, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Qin Wan
- Section on Epithelial and Retinal Physiology and Disease, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Ruchi Sharma
- Unit on Ocular and Stem Cell Translational Research, National Eye Institute, National Institute of Health, Bethesda, MD, USA
| | - Mostafa Lotfi
- Section on Epithelial and Retinal Physiology and Disease, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Arvydas Maminishkis
- Section on Epithelial and Retinal Physiology and Disease, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Kapil Bharti
- Unit on Ocular and Stem Cell Translational Research, National Eye Institute, National Institute of Health, Bethesda, MD, USA.
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14
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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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Chao JR, Knight K, Engel AL, Jankowski C, Wang Y, Manson MA, Gu H, Djukovic D, Raftery D, Hurley JB, Du J. Human retinal pigment epithelial cells prefer proline as a nutrient and transport metabolic intermediates to the retinal side. J Biol Chem 2017; 292:12895-12905. [PMID: 28615447 DOI: 10.1074/jbc.m117.788422] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 05/30/2017] [Indexed: 11/06/2022] Open
Abstract
Metabolite transport is a major function of the retinal pigment epithelium (RPE) to support the neural retina. RPE dysfunction plays a significant role in retinal degenerative diseases. We have used mass spectrometry with 13C tracers to systematically study nutrient consumption and metabolite transport in cultured human fetal RPE. LC/MS-MS detected 120 metabolites in the medium from either the apical or basal side. Surprisingly, more proline is consumed than any other nutrient, including glucose, taurine, lipids, vitamins, or other amino acids. Besides being oxidized through the Krebs cycle, proline is used to make citrate via reductive carboxylation. Citrate, made either from 13C proline or from 13C glucose, is preferentially exported to the apical side and is taken up by the retina. In conclusion, RPE cells consume multiple nutrients, including glucose and taurine, but prefer proline, and they actively synthesize and export metabolic intermediates to the apical side to nourish the outer retina.
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Affiliation(s)
- Jennifer R Chao
- Department of Ophthalmology, University of Washington, Seattle, Washington 98109.
| | - Kaitlen Knight
- Department of Ophthalmology, University of Washington, Seattle, Washington 98109
| | - Abbi L Engel
- Department of Ophthalmology, University of Washington, Seattle, Washington 98109
| | - Connor Jankowski
- Department of Biochemistry, University of Washington, Seattle, Washington 98109
| | - Yekai Wang
- Department of Ophthalmology, West Virginia University, Morgantown, West Virginia 26506; Department of Biochemistry, West Virginia University, Morgantown, West Virginia 26506
| | - Megan A Manson
- Department of Ophthalmology, University of Washington, Seattle, Washington 98109
| | - Haiwei Gu
- Northwest Metabolomics Research Center, Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington 98109
| | - Danijel Djukovic
- Northwest Metabolomics Research Center, Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington 98109
| | - Daniel Raftery
- Northwest Metabolomics Research Center, Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington 98109
| | - James B Hurley
- Department of Ophthalmology, University of Washington, Seattle, Washington 98109; Department of Biochemistry, University of Washington, Seattle, Washington 98109
| | - Jianhai Du
- Department of Ophthalmology, West Virginia University, Morgantown, West Virginia 26506; Department of Biochemistry, West Virginia University, Morgantown, West Virginia 26506.
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16
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Iacovelli J, Rowe GC, Khadka A, Diaz-Aguilar D, Spencer C, Arany Z, Saint-Geniez M. PGC-1α Induces Human RPE Oxidative Metabolism and Antioxidant Capacity. Invest Ophthalmol Vis Sci 2016; 57:1038-51. [PMID: 26962700 PMCID: PMC4788093 DOI: 10.1167/iovs.15-17758] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Purpose Oxidative stress and metabolic dysregulation of the RPE have been implicated in AMD; however, the molecular regulation of RPE metabolism remains unclear. The transcriptional coactivator, peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α) is a powerful mediator of mitochondrial function. This study examines the ability of PGC-1α to regulate RPE metabolic program and oxidative stress response. Methods Primary human fetal RPE (hfRPE) and ARPE-19 were matured in vitro using standard culture conditions. Mitochondrial mass of RPE was measured using MitoTracker staining and citrate synthase activity. Expression of PGC-1 isoforms, RPE-specific genes, oxidative metabolism proteins, and antioxidant enzymes was analyzed by quantitative PCR and Western blot. Mitochondrial respiration and fatty-acid oxidation were monitored using the Seahorse extracellular flux analyzer. Expression of PGC-1α was increased using adenoviral delivery. ARPE-19 were exposed to hydrogen peroxide to induce oxidative stress. Reactive oxygen species were measured by CM-H2DCFDA fluorescence. Cell death was analyzed by LDH release. Results Maturation of ARPE-19 and hfRPE was associated with significant increase in mitochondrial mass, expression of oxidative phosphorylation (OXPHOS) genes, and PGC-1α gene expression. Overexpression of PGC-1α increased expression of OXPHOS and fatty-acid β-oxidation genes, ultimately leading to the potent induction of mitochondrial respiration and fatty-acid oxidation. PGC-1α gain of function also strongly induced numerous antioxidant genes and, importantly, protected RPE from oxidant-mediated cell death without altering RPE functions. Conclusions This study provides important insights into the metabolic changes associated with RPE functional maturation and identifies PGC-1α as a potent driver of RPE mitochondrial function and antioxidant capacity.
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Affiliation(s)
- Jared Iacovelli
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, United States 2Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
| | - Glenn C Rowe
- Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Arogya Khadka
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, United States
| | - Daniel Diaz-Aguilar
- Angiogenesis Laboratory, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, United States
| | - Carrie Spencer
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, United States
| | - Zoltan Arany
- Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Magali Saint-Geniez
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, United States 2Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
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17
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Hotaling NA, Khristov V, Wan Q, Sharma R, Jha BS, Lotfi M, Maminishkis A, Simon CG, Bharti K. Nanofiber Scaffold-Based Tissue-Engineered Retinal Pigment Epithelium to Treat Degenerative Eye Diseases. J Ocul Pharmacol Ther 2016; 32:272-85. [PMID: 27110730 PMCID: PMC4904235 DOI: 10.1089/jop.2015.0157] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 03/24/2016] [Indexed: 12/16/2022] Open
Abstract
Clinical-grade manufacturing of a functional retinal pigment epithelium (RPE) monolayer requires reproducing, as closely as possible, the natural environment in which RPE grows. In vitro, this can be achieved by a tissue engineering approach, in which the RPE is grown on a nanofibrous biological or synthetic scaffold. Recent research has shown that nanofiber scaffolds perform better for cell growth and transplantability compared with their membrane counterparts and that the success of the scaffold in promoting cell growth/function is not heavily material dependent. With these strides, the field has advanced enough to begin to consider implementation of one, or a combination, of the tissue engineering strategies discussed herein. In this study, we review the current state of tissue engineering research for in vitro culture of RPE/scaffolds and the parameters for optimal scaffold design that have been uncovered during this research. Next, we discuss production methods and manufacturers that are capable of producing the nanofiber scaffolds in such a way that would be biologically, regulatory, clinically, and commercially viable. Then, a discussion of how the scaffolds could be characterized, both morphologically and mechanically, to develop a testing process that is viable for regulatory screening is performed. Finally, an example of a tissue-engineered RPE/scaffold construct is given to provide the reader a framework for understanding how these pieces could fit together to develop a tissue-engineered RPE/scaffold construct that could pass regulatory scrutiny and can be commercially successful.
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Affiliation(s)
- Nathan A. Hotaling
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, Maryland
- Unit on Ocular and Stem Cell Translational Research, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Vladimir Khristov
- Section of Epithelial and Retinal Physiology and Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Qin Wan
- Section of Epithelial and Retinal Physiology and Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Ruchi Sharma
- Unit on Ocular and Stem Cell Translational Research, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Balendu Shekhar Jha
- Unit on Ocular and Stem Cell Translational Research, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Mostafa Lotfi
- Section of Epithelial and Retinal Physiology and Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Arvydas Maminishkis
- Section of Epithelial and Retinal Physiology and Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Carl G. Simon
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, Maryland
| | - Kapil Bharti
- Unit on Ocular and Stem Cell Translational Research, National Eye Institute, National Institutes of Health, Bethesda, Maryland
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18
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Song MJ, Bharti K. Looking into the future: Using induced pluripotent stem cells to build two and three dimensional ocular tissue for cell therapy and disease modeling. Brain Res 2016; 1638:2-14. [PMID: 26706569 PMCID: PMC4837038 DOI: 10.1016/j.brainres.2015.12.011] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 11/24/2015] [Accepted: 12/08/2015] [Indexed: 01/02/2023]
Abstract
Retinal degenerative diseases are the leading cause of irreversible vision loss in developed countries. In many cases the diseases originate in the homeostatic unit in the back of the eye that contains the retina, retinal pigment epithelium (RPE) and the choriocapillaris. RPE is a central and a critical component of this homeostatic unit, maintaining photoreceptor function and survival on the apical side and choriocapillaris health on the basal side. In diseases like age-related macular degeneration (AMD), it is thought that RPE dysfunctions cause disease-initiating events and as the RPE degenerates photoreceptors begin to die and patients start loosing vision. Patient-specific induced pluripotent stem (iPS) cell-derived RPE provides direct access to a patient's genetics and allow the possibility of identifying the initiating events of RPE-associated degenerative diseases. Furthermore, iPS cell-derived RPE cells are being tested as a potential cell replacement in disease stages with RPE atrophy. In this article we summarize the recent progress in the field of iPS cell-derived RPE "disease modeling" and cell therapies and also discuss the possibilities of developing a model of the entire homeostatic unit to aid in studying disease processes in the future. This article is part of a Special Issue entitled SI: PSC and the brain.
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Affiliation(s)
- Min Jae Song
- Unit on Ocular and Stem Cell Translational Research National Eye Institute, 10 Center Drive, Room 10B10, Bethesda, MD 20892, United States
| | - Kapil Bharti
- Unit on Ocular and Stem Cell Translational Research National Eye Institute, 10 Center Drive, Room 10B10, Bethesda, MD 20892, United States.
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Vollrath D, Yasumura D, Benchorin G, Matthes MT, Feng W, Nguyen NM, Sedano CD, Calton MA, LaVail MM. Tyro3 Modulates Mertk-Associated Retinal Degeneration. PLoS Genet 2015; 11:e1005723. [PMID: 26656104 PMCID: PMC4687644 DOI: 10.1371/journal.pgen.1005723] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 11/13/2015] [Indexed: 01/24/2023] Open
Abstract
Inherited photoreceptor degenerations (IPDs) are the most genetically heterogeneous of Mendelian diseases. Many IPDs exhibit substantial phenotypic variability, but the basis is usually unknown. Mutations in MERTK cause recessive IPD phenotypes associated with the RP38 locus. We have identified a murine genetic modifier of Mertk-associated photoreceptor degeneration, the C57BL/6 (B6) allele of which acts as a suppressor. Photoreceptors degenerate rapidly in Mertk-deficient animals homozygous for the 129P2/Ola (129) modifier allele, whereas animals heterozygous for B6 and 129 modifier alleles exhibit an unusual intermixing of degenerating and preserved retinal regions, with females more severely affected than males. Mertk-deficient mice homozygous for the B6 modifier allele display degeneration only in the far periphery, even at 8 months of age, and have improved retinal function compared to animals homozygous for the 129 allele. We genetically mapped the modifier to an approximately 2-megabase critical interval that includes Tyro3, a paralog of Mertk. Tyro3 expression in the outer retina varies with modifier genotype in a manner characteristic of a cis-acting expression quantitative trait locus (eQTL), with the B6 allele conferring an approximately three-fold higher expression level. Loss of Tyro3 function accelerates the pace of photoreceptor degeneration in Mertk knockout mice, and TYRO3 protein is more abundant in the retinal pigment epithelium (RPE) adjacent to preserved central retinal regions of Mertk knockout mice homozygous for the B6 modifier allele. Endogenous human TYRO3 protein co-localizes with nascent photoreceptor outer segment (POS) phagosomes in a primary RPE cell culture assay, and expression of murine Tyro3 in cultured cells stimulates phagocytic ingestion of POS. Our findings demonstrate that Tyro3 gene dosage modulates Mertk-associated retinal degeneration, provide strong evidence for a direct role for TYRO3 in RPE phagocytosis, and suggest that an eQTL can modify a recessive IPD.
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Affiliation(s)
- Douglas Vollrath
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
- * E-mail:
| | - Douglas Yasumura
- Beckman Vision Center, University of California San Francisco, San Francisco, California, United States of America
| | - Gillie Benchorin
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Michael T. Matthes
- Beckman Vision Center, University of California San Francisco, San Francisco, California, United States of America
| | - Wei Feng
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Natalie M. Nguyen
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Cecilia D. Sedano
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Melissa A. Calton
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Matthew M. LaVail
- Beckman Vision Center, University of California San Francisco, San Francisco, California, United States of America
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Pennington BO, Clegg DO, Melkoumian ZK, Hikita ST. Defined culture of human embryonic stem cells and xeno-free derivation of retinal pigmented epithelial cells on a novel, synthetic substrate. Stem Cells Transl Med 2015; 4:165-77. [PMID: 25593208 DOI: 10.5966/sctm.2014-0179] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Age-related macular degeneration (AMD), a leading cause of blindness, is characterized by the death of the retinal pigmented epithelium (RPE), which is a monolayer posterior to the retina that supports the photoreceptors. Human embryonic stem cells (hESCs) can generate an unlimited source of RPE for cellular therapies, and clinical trials have been initiated. However, protocols for RPE derivation using defined conditions free of nonhuman derivatives (xeno-free) are preferred for clinical translation. This avoids exposing AMD patients to animal-derived products, which could incite an immune response. In this study, we investigated the maintenance of hESCs and their differentiation into RPE using Synthemax II-SC, which is a novel, synthetic animal-derived component-free, RGD peptide-containing copolymer compliant with good manufacturing practices designed for xeno-free stem cell culture. Cells on Synthemax II-SC were compared with cultures grown with xenogeneic and xeno-free control substrates. This report demonstrates that Synthemax II-SC supports long-term culture of H9 and H14 hESC lines and permits efficient differentiation of hESCs into functional RPE. Expression of RPE-specific markers was assessed by flow cytometry, quantitative polymerase chain reaction, and immunocytochemistry, and RPE function was determined by phagocytosis of rod outer segments and secretion of pigment epithelium-derived factor. Both hESCs and hESC-RPE maintained normal karyotypes after long-term culture on Synthemax II-SC. Furthermore, RPE generated on Synthemax II-SC are functional when seeded onto parylene-C scaffolds designed for clinical use. These experiments suggest that Synthemax II-SC is a suitable, defined substrate for hESC culture and the xeno-free derivation of RPE for cellular therapies.
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Affiliation(s)
- Britney O Pennington
- Center for Stem Cell Biology and Engineering, Neuroscience Research Institute, Biomolecular Science and Engineering Program and Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, California, USA; Corning Life Sciences Development, Corning Inc., Corning, New York, USA; Asterias Biotherapeutics, Inc., Menlo Park, California, USA
| | - Dennis O Clegg
- Center for Stem Cell Biology and Engineering, Neuroscience Research Institute, Biomolecular Science and Engineering Program and Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, California, USA; Corning Life Sciences Development, Corning Inc., Corning, New York, USA; Asterias Biotherapeutics, Inc., Menlo Park, California, USA
| | - Zara K Melkoumian
- Center for Stem Cell Biology and Engineering, Neuroscience Research Institute, Biomolecular Science and Engineering Program and Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, California, USA; Corning Life Sciences Development, Corning Inc., Corning, New York, USA; Asterias Biotherapeutics, Inc., Menlo Park, California, USA
| | - Sherry T Hikita
- Center for Stem Cell Biology and Engineering, Neuroscience Research Institute, Biomolecular Science and Engineering Program and Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, California, USA; Corning Life Sciences Development, Corning Inc., Corning, New York, USA; Asterias Biotherapeutics, Inc., Menlo Park, California, USA
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21
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Boatright JH, Dalal N, Chrenek MA, Gardner C, Ziesel A, Jiang Y, Grossniklaus HE, Nickerson JM. Methodologies for analysis of patterning in the mouse RPE sheet. Mol Vis 2015; 21:40-60. [PMID: 25593512 PMCID: PMC4301600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Accepted: 01/12/2015] [Indexed: 11/23/2022] Open
Abstract
PURPOSE Our goal was to optimize procedures for assessing shapes, sizes, and other quantitative metrics of retinal pigment epithelium (RPE) cells and contact- and noncontact-mediated cell-to-cell interactions across a large series of flatmount RPE images. METHODS The two principal methodological advances of this study were optimization of a mouse RPE flatmount preparation and refinement of open-access software to rapidly analyze large numbers of flatmount images. Mouse eyes were harvested, and extra-orbital fat and muscles were removed. Eyes were fixed for 10 min, and dissected by puncturing the cornea with a sharp needle or a stab knife. Four radial cuts were made with iridectomy scissors from the puncture to near the optic nerve head. The lens, iris, and the neural retina were removed, leaving the RPE sheet exposed. The dissection and outcomes were monitored and evaluated by video recording. The RPE sheet was imaged under fluorescence confocal microscopy after staining for ZO-1 to identify RPE cell boundaries. Photoshop, Java, Perl, and Matlab scripts, as well as CellProfiler, were used to quantify selected parameters. Data were exported into Excel spreadsheets for further analysis. RESULTS A simplified dissection procedure afforded a consistent source of images that could be processed by computer. The dissection and flatmounting techniques were illustrated in a video recording. Almost all of the sheet could be routinely imaged, and substantial fractions of the RPE sheet (usually 20-50% of the sheet) could be analyzed. Several common technical problems were noted and workarounds developed. The software-based analysis merged 25 to 36 images into one and adjusted settings to record an image suitable for large-scale identification of cell-to-cell boundaries, and then obtained quantitative descriptors of the shape of each cell, its neighbors, and interactions beyond direct cell-cell contact in the sheet. To validate the software, human- and computer-analyzed results were compared. Whether tallied manually or automatically with software, the resulting cell measurements were in close agreement. We compared normal with diseased RPE cells during aging with quantitative cell size and shape metrics. Subtle differences between the RPE sheet characteristics of young and old mice were identified. The IRBP(-/-) mouse RPE sheet did not differ from C57BL/6J (wild type, WT), suggesting that IRBP does not play a direct role in maintaining the health of the RPE cell, while the slow loss of photoreceptor (PhR) cells previously established in this knockout does support a role in the maintenance of PhR cells. Rd8 mice exhibited several measurable changes in patterns of RPE cells compared to WT, suggesting a slow degeneration of the RPE sheet that had not been previously noticed in rd8. CONCLUSIONS An optimized dissection method and a series of programs were used to establish a rapid and hands-off analysis. The software-aided, high-sampling-size approach performed as well as trained human scorers, but was considerably faster and easier. This method allows tens to hundreds of thousands of cells to be analyzed, each with 23 metrics. With this combination of dissection and image analysis of the RPE sheet, we can now analyze cell-to-cell interactions of immediate neighbors. In the future, we may be able to observe interactions of second, third, or higher ring neighbors and analyze tension in sheets, which might be expected to deviate from normal near large bumps in the RPE sheet caused by druse or when large frank holes in the RPE sheet are observed in geographic atrophy. This method and software can be readily applied to other aspects of vision science, neuroscience, and epithelial biology where patterns may exist in a sheet or surface of cells.
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Affiliation(s)
| | - Nupur Dalal
- Department of Ophthalmology, Emory University, Atlanta, GA
| | | | | | - Alison Ziesel
- Department of Ophthalmology, Emory University, Atlanta, GA
| | - Yi Jiang
- Department of Mathematics and Statistics, Georgia State University, Atlanta, GA
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Wolkow N, Li Y, Maminishkis A, Song Y, Alekseev O, Iacovelli J, Song D, Lee JC, Dunaief JL. Iron upregulates melanogenesis in cultured retinal pigment epithelial cells. Exp Eye Res 2014; 128:92-101. [PMID: 25277027 DOI: 10.1016/j.exer.2014.09.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 09/12/2014] [Accepted: 09/26/2014] [Indexed: 12/20/2022]
Abstract
The purpose of our studies was to examine the relationship between iron and melanogenesis in retinal pigment epithelial cells, as prior observations had suggested that iron may promote melanogenesis. This relationship has potential clinical importance, as both iron overload and hyperpigmentation are associated with age-related macular degeneration (AMD). Human fetal retinal pigment epithelial cells and ARPE-19 cells were treated with iron in the form of ferric ammonium citrate, after which quantitative RT-PCR and electron microscopy were performed. Melanogenesis genes tyrosinase, tyrosinase-related protein 1, Hermansky-Pudlak Syndrome 3, premelanosome protein and dopachrome tautomerase were upregulated, as was the melanogenesis-controlling transcription factor, microphthalmia-associated transcription factor (MITF). Iron-treated cells had increased pigmentation and melanosome number. Multiple transcription factors upstream of MITF were upregulated by iron.
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Affiliation(s)
- Natalie Wolkow
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratories, 422 Curie Blvd, Philadelphia, PA 19104, USA
| | - Yafeng Li
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratories, 422 Curie Blvd, Philadelphia, PA 19104, USA
| | - Arvydas Maminishkis
- Section of Epithelial and Retinal Physiology and Disease, National Eye Institute, National Institutes of Health, Bldg. 10, Rm. 10B04, MSC 1861, 10 Center Drive, Bethesda, MD 20892, USA
| | - Ying Song
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratories, 422 Curie Blvd, Philadelphia, PA 19104, USA
| | - Oleg Alekseev
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratories, 422 Curie Blvd, Philadelphia, PA 19104, USA
| | - Jared Iacovelli
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratories, 422 Curie Blvd, Philadelphia, PA 19104, USA
| | - Delu Song
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratories, 422 Curie Blvd, Philadelphia, PA 19104, USA
| | - Jennifer C Lee
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratories, 422 Curie Blvd, Philadelphia, PA 19104, USA
| | - Joshua L Dunaief
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratories, 422 Curie Blvd, Philadelphia, PA 19104, USA.
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Adijanto J, Philp NJ. Cultured primary human fetal retinal pigment epithelium (hfRPE) as a model for evaluating RPE metabolism. Exp Eye Res 2014; 126:77-84. [PMID: 24485945 DOI: 10.1016/j.exer.2014.01.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 01/15/2014] [Accepted: 01/19/2014] [Indexed: 12/20/2022]
Abstract
Mitochondrial dysfunction has been shown to contribute to age-related and proliferative retinal diseases. Over the past decade, the primary human fetal RPE (hfRPE) culture model has emerged as an effective tool for studying RPE function and mechanisms of retinal diseases. This model system has been rigorously characterized and shown to closely resemble native RPE cells at the genomic and protein level, and that they are capable of accomplishing the characteristic functions of a healthy native RPE (e.g., rod phagocytosis, ion and fluid transport, and retinoid cycle). In this review, we demonstrated that the metabolic activity of the RPE is an indicator of its health and state of differentiation, and present the hfRPE culture model as a valuable in vitro system for evaluating RPE metabolism in the context of RPE differentiation and retinal disease.
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Affiliation(s)
- Jeffrey Adijanto
- Thomas Jefferson University, Dept. of Pathology, Anatomy, & Cell Biology, 1020 Locust Street, Rm315, Philadelphia, PA 19107, USA.
| | - Nancy J Philp
- Thomas Jefferson University, Dept. of Pathology, Anatomy, & Cell Biology, 1020 Locust Street, Rm315, Philadelphia, PA 19107, USA.
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25
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Gomez-Touriño IM, Senra A, Garcia F. Nucleofection of whole murine retinas. Cytotechnology 2012; 65:523-32. [PMID: 23132682 DOI: 10.1007/s10616-012-9509-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 10/10/2012] [Indexed: 11/26/2022] Open
Abstract
The mouse retina constitutes an important research model for studies aiming to unravel the cellular and molecular mechanisms underlying ocular diseases. The accessibility of this tissue and its feasibility to directly obtain neurons from it has increased the number of studies culturing mouse retina, mainly retinal cell suspensions. However, to address many questions concerning retinal diseases and protein function, the organotypic structure must be maintained, so it becomes important to devise methods to transfect and culture whole retinas without disturbing their cellular structure. Moreover, the postmitotic stage of retinal neurons makes them reluctant to commonly used transfection techniques. For this purpose some published methods employ in vivo virus-based transfection techniques or biolistics, methods that present some constraints. Here we report for the first time a method to transfect P15-P20 whole murine retinas via nucleofection, where nucleic acids are directly delivered to the cell nuclei, allowing in vitro transfection of postmitotic cells. A detailed protocol for successful retina extraction, organotypic culture, nucleofection, histological procedures and imaging is described. In our hands the A-33 nucleofector program shows the highest transfection efficiency. Whole flat-mount retinas and cryosections from transfected retinas were imaged by epifluorescence and confocal microscopy, showing that not only cells located in the outermost retinal layers, but also those in inner retinal layers are transfected. In conclusion, we present a novel method to successfully transfect postnatal whole murine retina via nucleofection, showing that retina can be successfully nucleofected after some optimization steps.
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Affiliation(s)
- Iria Maria Gomez-Touriño
- CIMUS (Department of Physiology), School of Medicine, University of Santiago de Compostela, Avd. Barcelona, 15782, Santiago de Compostela, Spain,
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Rizzolo LJ, Peng S, Luo Y, Xiao W. Integration of tight junctions and claudins with the barrier functions of the retinal pigment epithelium. Prog Retin Eye Res 2011; 30:296-323. [PMID: 21704180 DOI: 10.1016/j.preteyeres.2011.06.002] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 06/01/2011] [Accepted: 06/06/2011] [Indexed: 02/02/2023]
Abstract
The retinal pigment epithelium (RPE) forms the outer blood-retinal barrier by regulating the movement of solutes between the fenestrated capillaries of the choroid and the photoreceptor layer of the retina. Blood-tissue barriers use various mechanisms to accomplish their tasks including membrane pumps, transporters, and channels, transcytosis, metabolic alteration of solutes in transit, and passive but selective diffusion. The last category includes tight junctions, which regulate transepithelial diffusion through the spaces between neighboring cells of the monolayer. Tight junctions are extraordinarily complex structures that are dynamically regulated. Claudins are a family of tight junctional proteins that lend tissue specificity and selectivity to tight junctions. This review discusses how the claudins and tight junctions of the RPE differ from other epithelia and how its functions are modulated by the neural retina. Studies of RPE-retinal interactions during development lend insight into this modulation. Notably, the characteristics of RPE junctions, such as claudin composition, vary among species, which suggests the physiology of the outer retina may also vary. Comparative studies of barrier functions among species should deepen our understanding of how homeostasis is maintained in the outer retina. Stem cells provide a way to extend these studies of RPE-retinal interactions to human RPE.
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Affiliation(s)
- Lawrence J Rizzolo
- Department of Surgery and Department of Ophthalmology and Visual Science, Yale University School of Medicine, PO Box 208062, New Haven, CT 06520-8062, USA.
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