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Esposito E, Pozza E, Contado C, Pula W, Bortolini O, Ragno D, Toldo S, Casciano F, Bondi A, Zauli E, Secchiero P, Zauli G, Melloni E. Microfluidic Fabricated Liposomes for Nutlin-3a Ocular Delivery as Potential Candidate for Proliferative Vitreoretinal Diseases Treatment. Int J Nanomedicine 2024; 19:3513-3536. [PMID: 38623081 PMCID: PMC11018138 DOI: 10.2147/ijn.s452134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 03/09/2024] [Indexed: 04/17/2024] Open
Abstract
Purpose Proliferative vitreoretinal diseases (PVDs) represent a heterogeneous group of pathologies characterized by the presence of retinal proliferative membranes, in whose development retinal pigment epithelium (RPE) is deeply involved. As the only effective treatment for PVDs at present is surgery, we aimed to investigate the potential therapeutic activity of Nutlin-3a, a small non-genotoxic inhibitor of the MDM2/p53 interaction, on ARPE-19 cell line and on human RPE primary cells, as in vitro models of RPE and, more importantly, to formulate and evaluate Nutlin-3a loaded liposomes designed for ophthalmic administration. Methods Liposomes were produced using an innovative approach by a microfluidic device under selection of different conditions. Liposome size distribution was evaluated by photon correlation spectroscopy and centrifugal field flow fractionation, while the liposome structure was studied by transmission electron microscopy and Fourier-transform infrared spectroscopy. The Nutlin-3a entrapment capacity was evaluated by ultrafiltration and HPLC. Nutlin-3a biological effectiveness as a solution or loaded in liposomes was evaluated by viability, proliferation, apoptosis and migration assays and by morphological analysis. Results The microfluidic formulative study enabled the selection of liposomes composed of phosphatidylcholine (PC) 5.4 or 8.2 mg/mL and 10% ethanol, characterized by roundish vesicular structures with 150-250 nm mean diameters. Particularly, liposomes based on the lower PC concentration were characterized by higher stability. Nutlin-3a was effectively encapsulated in liposomes and was able to induce a significant reduction of viability and migration in RPE cell models. Conclusion Our results lay the basis for a possible use of liposomes for the ocular delivery of Nutlin-3a.
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Affiliation(s)
- Elisabetta Esposito
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, Ferrara, I-44121, Italy
| | - Elena Pozza
- Department of Translational Medicine, University of Ferrara, Ferrara, I-44121, Italy
| | - Catia Contado
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, Ferrara, I-44121, Italy
| | - Walter Pula
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, Ferrara, I-44121, Italy
| | - Olga Bortolini
- Department of Environmental Sciences and Prevention, University of Ferrara, Ferrara, I-44121, Italy
| | - Daniele Ragno
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, Ferrara, I-44121, Italy
| | - Sofia Toldo
- Department of Environmental Sciences and Prevention, University of Ferrara, Ferrara, I-44121, Italy
| | - Fabio Casciano
- Department of Translational Medicine and LTTA Centre, University of Ferrara, Ferrara, I-44121, Italy
| | - Agnese Bondi
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, Ferrara, I-44121, Italy
| | - Enrico Zauli
- Department of Translational Medicine, University of Ferrara, Ferrara, I-44121, Italy
| | - Paola Secchiero
- Department of Translational Medicine and LTTA Centre, University of Ferrara, Ferrara, I-44121, Italy
| | - Giorgio Zauli
- Department of Environmental Sciences and Prevention, University of Ferrara, Ferrara, I-44121, Italy
| | - Elisabetta Melloni
- Department of Translational Medicine and LTTA Centre, University of Ferrara, Ferrara, I-44121, Italy
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2
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Miller RD, Ratnayaka JA. Impaired lysosomes in the retinal pigment epithelium play a central role in the degeneration of the neuroretina. Neural Regen Res 2023; 18:2697-2698. [PMID: 37449628 DOI: 10.4103/1673-5374.373713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2023] Open
Affiliation(s)
- Rebecca D Miller
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | - J Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
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3
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Lindell M, Kar D, Sedova A, Kim YJ, Packer OS, Schmidt-Erfurth U, Sloan KR, Marsh M, Dacey DM, Curcio CA, Pollreisz A. Volumetric Reconstruction of a Human Retinal Pigment Epithelial Cell Reveals Specialized Membranes and Polarized Distribution of Organelles. Invest Ophthalmol Vis Sci 2023; 64:35. [PMID: 38133501 PMCID: PMC10746928 DOI: 10.1167/iovs.64.15.35] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 11/04/2023] [Indexed: 12/23/2023] Open
Abstract
Purpose Despite the centrality of the retinal pigment epithelium (RPE) in vision and retinopathy our picture of RPE morphology is incomplete. With a volumetric reconstruction of human RPE ultrastructure, we aim to characterize major membranous features including apical processes and their interactions with photoreceptor outer segments, basolateral infoldings, and the distribution of intracellular organelles. Methods A parafoveal retinal sample was acquired from a 21-year-old male organ donor. With serial block-face scanning electron microscopy, a tissue volume from the inner-outer segment junction to basal RPE was captured. Surface membranes and complete internal ultrastructure of an individual RPE cell were achieved with a combination of manual and automated segmentation methods. Results In one RPE cell, apical processes constitute 69% of the total cell surface area, through a dense network of over 3000 terminal branches. Single processes contact several photoreceptors. Basolateral infoldings facing the choriocapillaris resemble elongated filopodia and comprise 22% of the cell surface area. Membranous tubules and sacs of endoplasmic reticulum represent 20% of the cell body volume. A dense basal layer of mitochondria extends apically to partly overlap electron-dense pigment granules. Pores in the nuclear envelope form a distinct pattern of rows aligned with chromatin. Conclusions Specialized membranes at the apical and basal side of the RPE cell body involved in intercellular uptake and transport represent over 90% of the total surface area. Together with the polarized distribution of organelles within the cell body, these findings are relevant for retinal clinical imaging, therapeutic approaches, and disease pathomechanisms.
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Affiliation(s)
- Maximilian Lindell
- Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
| | - Deepayan Kar
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Aleksandra Sedova
- Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
| | - Yeon Jin Kim
- Department of Biological Structure, University of Washington, Seattle, Washington, United States
| | - Orin S. Packer
- Department of Biological Structure, University of Washington, Seattle, Washington, United States
| | | | - Kenneth R. Sloan
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Mike Marsh
- Object Research Systems, Montreal, Quebec, Canada
| | - Dennis M. Dacey
- Department of Biological Structure, University of Washington, Seattle, Washington, United States
| | - Christine A. Curcio
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Andreas Pollreisz
- Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
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Ren J, Zhang S, Pan Y, Jin M, Li J, Luo Y, Sun X, Li G. Diabetic retinopathy: Involved cells, biomarkers, and treatments. Front Pharmacol 2022; 13:953691. [PMID: 36016568 PMCID: PMC9396039 DOI: 10.3389/fphar.2022.953691] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 07/06/2022] [Indexed: 11/13/2022] Open
Abstract
Diabetic retinopathy (DR), a leading cause of vision loss and blindness worldwide, is caused by retinal neurovascular unit dysfunction, and its cellular pathology involves at least nine kinds of retinal cells, including photoreceptors, horizontal and bipolar cells, amacrine cells, retinal ganglion cells, glial cells (Müller cells, astrocytes, and microglia), endothelial cells, pericytes, and retinal pigment epithelial cells. Its mechanism is complicated and involves loss of cells, inflammatory factor production, neovascularization, and BRB impairment. However, the mechanism has not been completely elucidated. Drug treatment for DR has been gradually advancing recently. Research on potential drug targets relies upon clear information on pathogenesis and effective biomarkers. Therefore, we reviewed the recent literature on the cellular pathology and the diagnostic and prognostic biomarkers of DR in terms of blood, protein, and clinical and preclinical drug therapy (including synthesized molecules and natural molecules). This review may provide a theoretical basis for further DR research.
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Affiliation(s)
- Jiahui Ren
- Institute of Medicinal Plant Development, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
- Beijing Key Laboratory of Innovative Drug Discovery of Traditional Chinese Medicine (Natural Medicine) and Translational Medicine, Beijing, China
- Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine, Ministry of Education, Beijing, China
- Yunnan Branch, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Jinghong, China
- Yunnan Key Laboratory of Southern Medicine Utilization, Kunming, China
| | - Shuxia Zhang
- Institute of Medicinal Plant Development, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
- Beijing Key Laboratory of Innovative Drug Discovery of Traditional Chinese Medicine (Natural Medicine) and Translational Medicine, Beijing, China
- Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine, Ministry of Education, Beijing, China
| | - Yunfeng Pan
- Institute of Medicinal Plant Development, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
- Beijing Key Laboratory of Innovative Drug Discovery of Traditional Chinese Medicine (Natural Medicine) and Translational Medicine, Beijing, China
- Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine, Ministry of Education, Beijing, China
| | - Meiqi Jin
- Institute of Medicinal Plant Development, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
- Beijing Key Laboratory of Innovative Drug Discovery of Traditional Chinese Medicine (Natural Medicine) and Translational Medicine, Beijing, China
- Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine, Ministry of Education, Beijing, China
| | - Jiaxin Li
- Yunnan Key Laboratory of Southern Medicine Utilization, Kunming, China
- College of Pharmacy, Heilongjiang University of Chinese Medicine, Harbin, China
| | - Yun Luo
- Institute of Medicinal Plant Development, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
- Beijing Key Laboratory of Innovative Drug Discovery of Traditional Chinese Medicine (Natural Medicine) and Translational Medicine, Beijing, China
- Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine, Ministry of Education, Beijing, China
- *Correspondence: Yun Luo, ; Xiaobo Sun , ; Guang Li,
| | - Xiaobo Sun
- Institute of Medicinal Plant Development, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
- Beijing Key Laboratory of Innovative Drug Discovery of Traditional Chinese Medicine (Natural Medicine) and Translational Medicine, Beijing, China
- Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine, Ministry of Education, Beijing, China
- *Correspondence: Yun Luo, ; Xiaobo Sun , ; Guang Li,
| | - Guang Li
- Institute of Medicinal Plant Development, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
- Yunnan Branch, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Jinghong, China
- Yunnan Key Laboratory of Southern Medicine Utilization, Kunming, China
- *Correspondence: Yun Luo, ; Xiaobo Sun , ; Guang Li,
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5
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Hazim RA, Paniagua AE, Tang L, Yang K, Kim KKO, Stiles L, Divakaruni AS, Williams DS. Vitamin B3, nicotinamide, enhances mitochondrial metabolism to promote differentiation of the retinal pigment epithelium. J Biol Chem 2022; 298:102286. [PMID: 35868562 PMCID: PMC9396405 DOI: 10.1016/j.jbc.2022.102286] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 07/14/2022] [Accepted: 07/15/2022] [Indexed: 01/04/2023] Open
Abstract
In the mammalian retina, a metabolic ecosystem exists in which photoreceptors acquire glucose from the choriocapillaris with the help of the retinal pigment epithelium (RPE). While the photoreceptor cells are primarily glycolytic, exhibiting Warburg-like metabolism, the RPE is reliant on mitochondrial respiration. However, the ways in which mitochondrial metabolism affect RPE cellular functions are not clear. We first used the human RPE cell line, ARPE-19, to examine mitochondrial metabolism in the context of cellular differentiation. We show that nicotinamide induced rapid differentiation of ARPE-19 cells, which was reversed by removal of supplemental nicotinamide. During the nicotinamide-induced differentiation, we observed using quantitative PCR, Western blotting, electron microscopy, and metabolic respiration and tracing assays that (1) mitochondrial gene and protein expression increased, (2) mitochondria became larger with more tightly folded cristae, and (3) mitochondrial metabolism was enhanced. In addition, we show that primary cultures of human fetal RPE cells responded similarly in the presence of nicotinamide. Furthermore, disruption of mitochondrial oxidation of pyruvate attenuated the nicotinamide-induced differentiation of the RPE cells. Together, our results demonstrate a remarkable effect of nicotinamide on RPE metabolism. We also identify mitochondrial respiration as a key contributor to the differentiated state of the RPE and thus to many of the RPE functions that are essential for retinal health and photoreception.
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Affiliation(s)
- Roni A Hazim
- Department of Ophthalmology and Stein Eye Institute
| | | | - Lisa Tang
- Department of Ophthalmology and Stein Eye Institute
| | - Krista Yang
- Department of Molecular and Medical Pharmacology, UCLA David Geffen School of Medicine, Los Angeles, CA 90095
| | - Kristen K O Kim
- Department of Molecular and Medical Pharmacology, UCLA David Geffen School of Medicine, Los Angeles, CA 90095
| | - Linsey Stiles
- Department of Molecular and Medical Pharmacology, UCLA David Geffen School of Medicine, Los Angeles, CA 90095; Department of Medicine, Endocrinology. UCLA David Geffen School of Medicine. Los Angeles, CA, 90095, USA
| | - Ajit S Divakaruni
- Department of Molecular and Medical Pharmacology, UCLA David Geffen School of Medicine, Los Angeles, CA 90095
| | - David S Williams
- Department of Ophthalmology and Stein Eye Institute; Department of Neurobiology, David Geffen School of Medicine at UCLA; Molecular Biology Institute; Brain Research Institute, University of California, Los Angeles, CA.
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Berkowitz BA, Podolsky RH, Childers KL, Burgoyne T, De Rossi G, Qian H, Roberts R, Katz R, Waseem R, Goodman C. Functional Changes Within the Rod Inner Segment Ellipsoid in Wildtype Mice: An Optical Coherence Tomography and Electron Microscopy Study. Invest Ophthalmol Vis Sci 2022; 63:8. [PMID: 35816042 PMCID: PMC9284466 DOI: 10.1167/iovs.63.8.8] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Purpose To test the hypothesis that changing energy needs alter mitochondria distribution within the rod inner segment ellipsoid. Methods In mice with relatively smaller (C57BL/6J [B6J]) or greater (129S6/ev [S6]) retina mitochondria maximum reserve capacity, the profile shape of the rod inner segment ellipsoid zone (ISez) was measured with optical coherence tomography (OCT) under higher (dark) or lower (light) energy demand conditions. ISez profile shape was characterized using an unbiased ellipse descriptor (minor/major aspect ratio). Other bioenergy indexes evaluated include the external limiting membrane-retinal pigment epithelium (ELM-RPE) thickness and the magnitude of the signal intensity of a hyporeflective band located between the photoreceptor tips and apical RPE. The spatial distribution of rod ellipsoid mitochondria were also examined with electron microscopy. Results In B6J mice, darkness produced a greater ISez aspect ratio, thinner ELM-RPE, and a smaller hyporeflective band intensity than in light. In S6 mice, dark and light ISez aspect ratio values were not different and were greater than in light-adapted B6J mice; dark-adapted S6 mice showed smaller ELM-RPE thinning versus light, and negligible hyporeflective band intensity in the light. In B6J mice, mitochondria number in light increased in the distal inner segment ellipsoid and decreased proximally. In S6 mice, mitochondria number in the inner segment ellipsoid were not different between light and dark, and were greater than in B6J mice. Conclusions These data raise the possibility that rod mitochondria activity in mice can be noninvasively evaluated based on the ISez profile shape, a new OCT index that complements OCT energy biomarkers measured outside of the ISez region.
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Affiliation(s)
- Bruce A Berkowitz
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Robert H Podolsky
- Biostatistics and Study Methodology, Children's National Hospital, Silver Spring, Maryland, United States
| | - Karen Lins Childers
- Beaumont Research Institute, Beaumont Health, Royal Oak, Michigan, Unites States
| | - Tom Burgoyne
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Giulia De Rossi
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Haohua Qian
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland, Unites States
| | - Robin Roberts
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Ryan Katz
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Rida Waseem
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Cole Goodman
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
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7
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Wang M, Wei J, Li H, Wang F. Changes in transepithelial electrical resistance and intracellular ion concentration in TGF-β-induced epithelial-mesenchymal transition of retinal pigment epithelial cells. Am J Transl Res 2022; 14:2728-2738. [PMID: 35559413 PMCID: PMC9091112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 04/06/2022] [Indexed: 06/15/2023]
Abstract
OBJECTIVE This study aimed to investigate the changes in transepithelial electrical resistance (TEER) and ion concentrations, and their relationship in TGF-β-induced epithelial-mesenchymal transition (EMT) of retinal pigment epithelial (RPE) cells. METHODS RPE cell line ARPE-19 was employed and treated with 10 ng/ml TGF-β1 and TGF-β2 to establish the EMT model in vitro. The EMT markers fibronectin, N-cadherin, occludin, zona occludens 1(ZO-1) and claudin-19 were investigated by western blot and immunofluorescence. CellZscope system was used to monitor the TEER values. Fluorescent probe, flow cytometry and automatic microplate reader were employed to detect the changes of Ca2+, Mg2+, Zn2+, Na+ and K+ in ARPE-19 cells. RESULTS The TGF-β1-induced EMT of ARPE-19 cells was marked by the disruption of the distribution of occludin, ZO-1, and claudin-19. The development of TEER was significantly disturbed in both TGF-β1 and TGF-β2 treatment groups. Also, the time course of the maximum slope indicated that the fastest decrease in TEER values occurred after 36 hours. The concentrations of Ca2+, Mg2+, Zn2+, and K+ increased in TGF-β1- and TGF-β2-treated ARPE-19 cells, while the concentration of Na+ decreased. Significant inverse correlations were detected between the concentrations of Ca2+, Mg2+, Zn2+, and K+ and TEER values in ARPE-19 cells treated with TGF-β1. The Na+ concentration and TEER values showed a positive correlation. Similar results were observed in the TGF-β2 treatment group. The time-effect analysis showed that the concentrations of Ca2+, Mg2+, Zn2+ and K+ increased and peaked after 72, 72, 48, and 72 h, respectively, with the extension of TGF-β1 treatment time. In the TGF-β2 treatment group, the Ca2+, Mg2+, Zn2+, and K+ concentrations were also upregulated and reached their highest after 72, 72, 72, and 36 h, respectively. In contrast, the concentration of Na+ decreased and reached the lowest after 48 h in the TGF-β1 treatment group and after 72 h in the TGF-β2 treatment group. CONCLUSION TGF-β1 and TGF-β2 disrupted the ARPE-19 cell monolayer, disturbed TJs integrity, downregulated TEER values, and changed intracellular ion permeability. These findings might help further understand the EMT of RPE cells during PVR.
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Affiliation(s)
- Minli Wang
- Department of Ophthalmology, Shanghai Tenth People’s Hospital, Tongji University School of MedicineShanghai 200072, China
| | - Jiayi Wei
- Department of Ophthalmology, Shanghai Tenth People’s Hospital, Tongji University School of MedicineShanghai 200072, China
| | - Hui Li
- Department of Ophthalmology, Shanghai Tenth People’s Hospital, Tongji University School of MedicineShanghai 200072, China
| | - Fang Wang
- Department of Ophthalmology, Shanghai Tenth People’s Hospital, Tongji University School of MedicineShanghai 200072, China
- Department of Ophthalmology, Shanghai Bright Eye HospitalShanghai 200336, China
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8
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Yazdani M. Uncontrolled Oxygen Levels in Cultures of Retinal Pigment Epithelium: Have We Missed the Obvious? Curr Eye Res 2022; 47:651-660. [PMID: 35243933 DOI: 10.1080/02713683.2022.2050264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Retinal pigment epithelium (RPE) is the outermost layer of retina located between the photoreceptor cells and the choroid. This highly-polarized monolayer provides critical support for the functioning of the other parts of the retina, especially photoreceptors. Methods of culturing RPE have been under development since its establishment in 1920s. Despite considering various factors, oxygen (O2) levels in RPE microenvironments during culture preparation and experimental procedure have been overlooked. O2 is a crucial parameter in the cultures, and therefore, maintaining RPE cells at O2 levels different from their native environment (70-90 mm Hg of O2) could have unintended consequences. Owing to the importance of the topic, lack of sufficient discussion in the literature and to encourage future research, this paper will focus on uncontrolled O2 level in cultures of RPE cells.
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Affiliation(s)
- Mazyar Yazdani
- Department of Medical Biochemistry, Oslo University Hospital, Rikshospitalet, 0027 Oslo, Norway
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9
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Jiao X, Ma Z, Lei J, Liu P, Cai X, Shahi PK, Chan CC, Fariss R, Pattnaik BR, Dong L, Hejtmancik JF. Retinal Development and Pathophysiology in Kcnj13 Knockout Mice. Front Cell Dev Biol 2022; 9:810020. [PMID: 35096838 PMCID: PMC8790323 DOI: 10.3389/fcell.2021.810020] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 12/10/2021] [Indexed: 11/22/2022] Open
Abstract
Purpose: We constructed and characterized knockout and conditional knockout mice for KCNJ13, encoding the inwardly rectifying K+ channel of the Kir superfamily Kir7.1, mutations in which cause both Snowflake Vitreoretinal Degeneration (SVD) and Retinitis pigmentosa (RP) to further elucidate the pathology of this disease and to develop a potential model system for gene therapy trials. Methods: A Kcnj13 knockout mouse line was constructed by inserting a gene trap cassette expressing beta-galactosidase flanked by FRT sites in intron 1 with LoxP sites flanking exon two and converted to a conditional knockout by FLP recombination followed by crossing with C57BL/6J mice having Cre driven by the VMD2 promoter. Lentiviral replacement of Kcnj13 was driven by the EF1a or VMD2 promoters. Results: Blue-Gal expression is evident in E12.5 brain ventricular choroid plexus, lens, neural retina layer, and anterior RPE. In the adult eye expression is seen in the ciliary body, RPE and choroid. Adult conditional Kcnj13 ko mice show loss of photoreceptors in the outer nuclear layer, inner nuclear layer thinning with loss of bipolar cells, and thinning and disruption of the outer plexiform layer, correlating with Cre expression in the overlying RPE which, although preserved, shows morphological disruption. Fundoscopy and OCT show signs of retinal degeneration consistent with the histology, and photopic and scotopic ERGs are decreased in amplitude or extinguished. Lentiviral based replacement of Kcnj13 resulted in increased ERG c- but not a- or b- wave amplitudes. Conclusion: Ocular KCNJ13 expression starts in the choroid, lens, ciliary body, and anterior retina, while later expression centers on the RPE with no/lower expression in the neuroretina. Although KCNJ13 expression is not required for survival of the RPE, it is necessary for RPE maintenance of the photoreceptors, and loss of the photoreceptor, outer plexiform, and outer nuclear layers occur in adult KCNJ13 cKO mice, concomitant with decreased amplitude and eventual extinguishing of the ERG and signs of retinitis pigmentosa on fundoscopy and OCT. Kcnj13 replacement resulting in recovery of the ERG c- but not a- and b-waves is consistent with the degree of photoreceptor degeneration seen on histology.
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Affiliation(s)
- Xiaodong Jiao
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Zhiwei Ma
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Jingqi Lei
- Genetic Engineering Core, National Eye Institute, National Institute of Health, Bethesda, MD, United States
| | - Pinghu Liu
- Genetic Engineering Core, National Eye Institute, National Institute of Health, Bethesda, MD, United States
| | - Xiaoyu Cai
- Genetic Engineering Core, National Eye Institute, National Institute of Health, Bethesda, MD, United States
| | - Pawan K Shahi
- Departments of Pediatrics and Ophthalmology and Visual Sciences and the McPherson Eye Research Institute, University of Wisconsin, Madison, AL, United States
| | - Chi-Chao Chan
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Robert Fariss
- Imaging Core, National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Bikash R Pattnaik
- Departments of Pediatrics and Ophthalmology and Visual Sciences and the McPherson Eye Research Institute, University of Wisconsin, Madison, AL, United States
| | - Lijin Dong
- Genetic Engineering Core, National Eye Institute, National Institute of Health, Bethesda, MD, United States
| | - J Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD, United States
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10
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Ratnayaka JA, Keeling E. Serial block face scanning electron microscopy reveals novel organizational details of the retinal pigment epithelium. Neural Regen Res 2022; 17:569-571. [PMID: 34380894 PMCID: PMC8504364 DOI: 10.4103/1673-5374.321002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- J Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Eloise Keeling
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
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11
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Abstract
The outer retina is nourished from the choroid, a capillary bed just inside the sclera. O2, glucose, and other nutrients diffuse out of the choroid and then filter through a monolayer of retinal pigment epithelium (RPE) cells to fuel the retina. Recent studies of energy metabolism have revealed striking differences between retinas and RPE cells in the ways that they extract energy from fuels. The purpose of this review is to suggest and evaluate the hypothesis that the retina and RPE have complementary metabolic roles that make them depend on each other for survival and for their abilities to perform essential and specialized functions. Expected final online publication date for the Annual Review of Vision Science, Volume 7 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- James B Hurley
- Departments of Biochemistry and Ophthalmology, University of Washington, Seattle, Washington 98115, USA;
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12
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Courson JA, Landry PT, Do T, Spehlmann E, Lafontant PJ, Patel N, Rumbaut RE, Burns AR. Serial Block-Face Scanning Electron Microscopy (SBF-SEM) of Biological Tissue Samples. J Vis Exp 2021:10.3791/62045. [PMID: 33843931 PMCID: PMC8225236 DOI: 10.3791/62045] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Serial block-face scanning electron microscopy (SBF-SEM) allows for the collection of hundreds to thousands of serially-registered ultrastructural images, offering an unprecedented three-dimensional view of tissue microanatomy. While SBF-SEM has seen an exponential increase in use in recent years, technical aspects such as proper tissue preparation and imaging parameters are paramount for the success of this imaging modality. This imaging system benefits from the automated nature of the device, allowing one to leave the microscope unattended during the imaging process, with the automated collection of hundreds of images possible in a single day. However, without appropriate tissue preparation cellular ultrastructure can be altered in such a way that incorrect or misleading conclusions might be drawn. Additionally, images are generated by scanning the block-face of a resin-embedded biological sample and this often presents challenges and considerations that must be addressed. The accumulation of electrons within the block during imaging, known as "tissue charging," can lead to a loss of contrast and an inability to appreciate cellular structure. Moreover, while increasing electron beam intensity/voltage or decreasing beam-scanning speed can increase image resolution, this can also have the unfortunate side effect of damaging the resin block and distorting subsequent images in the imaging series. Here we present a routine protocol for the preparation of biological tissue samples that preserves cellular ultrastructure and diminishes tissue charging. We also provide imaging considerations for the rapid acquisition of high-quality serial-images with minimal damage to the tissue block.
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Affiliation(s)
- Justin A. Courson
- University of Houston, College of Optometry, Houston, TX,
United States of America
| | - Paul T. Landry
- University of Houston, College of Optometry, Houston, TX,
United States of America
| | - Thao Do
- University of Houston, College of Optometry, Houston, TX,
United States of America
| | - Eric Spehlmann
- DePauw University, Department of Biology, Greencastle, IN,
United States of America
| | - Pascal J. Lafontant
- DePauw University, Department of Biology, Greencastle, IN,
United States of America
| | - Nimesh Patel
- University of Houston, College of Optometry, Houston, TX,
United States of America
| | - Rolando E. Rumbaut
- Center for Translational Research on Inflammatory Diseases
(CTRID), Michael E. DeBakey Veterans Affairs Medical Center, Houston, TX, United
States of America,Baylor College of Medicine, Children’s Nutrition
Center, Houston, TX, United States of America
| | - Alan R. Burns
- University of Houston, College of Optometry, Houston, TX,
United States of America,Baylor College of Medicine, Children’s Nutrition
Center, Houston, TX, United States of America
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