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Lim RR, Shirali S, Rowlan J, Engel AL, Nazario, M, Gonzalez K, Tong A, Neitz J, Neitz M, Chao JR. CFH Haploinsufficiency and Complement Alterations in Early-Onset Macular Degeneration. Invest Ophthalmol Vis Sci 2024; 65:43. [PMID: 38683564 PMCID: PMC11059804 DOI: 10.1167/iovs.65.4.43] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 04/03/2024] [Indexed: 05/01/2024] Open
Abstract
Purpose Complement dysregulation is a key component in the pathogenesis of age-related macular degeneration (AMD) and related diseases such as early-onset macular drusen (EOMD). Although genetic variants of complement factor H (CFH) are associated with AMD risk, the impact of CFH and factor H-like protein 1 (FHL-1) expression on local complement activity in human retinal pigment epithelium (RPE) remains unclear. Methods We identified a novel CFH variant in a family with EOMD and generated patient induced pluripotent stem cell (iPSC)-derived RPE cells. We assessed CFH and FHL-1 co-factor activity through C3b breakdown assays and measured complement activation by immunostaining for membrane attack complex (MAC) formation. Expression of CFH, FHL-1, local alternative pathway (AP) components, and regulators of complement activation (RCA) in EOMD RPE cells was determined by quantitative PCR, western blot, and immunostaining. Isogenic EOMD (cEOMD) RPE was generated using CRISPR/Cas9 gene editing. Results The CFH variant (c.351-2A>G) resulted in loss of CFH and FHL-1 expression and significantly reduced CFH and FHL-1 protein expression (∼50%) in EOMD iPSC RPE cells. These cells exhibited increased MAC deposition upon exposure to normal human serum. Under inflammatory or oxidative stress conditions, CFH and FHL-1 expression in EOMD RPE cells paralleled that of controls, whereas RCA expression, including MAC formation inhibitors, was elevated. CRISPR/Cas9 correction restored CFH/FHL-1 expression and mitigated alternative pathway complement activity in cEOMD RPE cells. Conclusions Identification of a novel CFH variant in patients with EOMD resulting in reduced CFH and FHL-1 and increased local complement activity in EOMD iPSC RPE supports the involvement of CFH haploinsufficiency in EOMD pathogenesis.
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Affiliation(s)
- Rayne R. Lim
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Sharlene Shirali
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Jessica Rowlan
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Abbi L. Engel
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Institute, Seattle, Washington, United States
| | - Marcos Nazario,
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Kelie Gonzalez
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Aspen Tong
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Jay Neitz
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Maureen Neitz
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Jennifer R. Chao
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
- Roger and Angie Karalis Johnson Retina Center, University of Washington School of Medicine, Seattle, Washington, United States
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Chen X, Chen L, Lin Y, Li G. Causality of Diabetic Nephropathy and Age-Related Macular Degeneration: A Mendelian Randomization Study. Gene 2023; 889:147787. [PMID: 37689221 DOI: 10.1016/j.gene.2023.147787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/19/2023] [Accepted: 09/06/2023] [Indexed: 09/11/2023]
Abstract
PURPOSE Age-related macular degeneration (AMD) currently stands as the leading cause of irreversible vision loss in the present era. The primary objective of this study was to investigate the causal relationships between diabetic nephropathy (DN), its associated risk factors, and AMD among participants of European descent. METHODS Genetic variants associated with DN and its risk factors, encompassing glycemic traits, lipidemic traits, systolic/diastolic blood pressure, obesity, and urate, were obtained from previously published genome-wide association studies. Summary-level statistics for AMD were acquired from the FinnGen database. Univariable and multivariable Mendelian randomization (MR) were employed to conduct this investigation. RESULTS Our MR analyses indicated that per 1-standard deviation (SD) increase of DN heightened the risk of overall AMD (p = 1.03 × 10-8, OR = 1.24). And these findings remained consistent when examining both dry AMD (p = 2.27 × 10-4, OR = 1.17) and wet AMD (p = 5.15 × 10-6, OR = 1.33). Additionally, there was a causal association between high-density lipoprotein-cholesterol (HDL-C) levels and an increased risk of AMD (p = 2.69 × 10-3, OR = 1.23), while triglycerides were found to mitigate the risk (p = 0.02, OR = 0.83). Notably, no significant associations were observed between other risk factors of DN and AMD. CONCLUSIONS These findings suggest that the impact of DN on the development of AMD may be more substantial than previously believed. Furthermore, elevated HDL-C levels appear to heighten the risk of AMD, whereas triglycerides may provide a protective effect.
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Affiliation(s)
- Xiaxue Chen
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, China
| | - Lanlan Chen
- Department of Hepatobiliary and Pancreatic Surgery, General Surgery Center, The First Hospital of Jilin University, China
| | - Yi Lin
- Department of Ophthalmology, The Third Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Guangyu Li
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, China.
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Kulshrestha P, Goel P, Murthy S, Tyagi M, Basu S, Gogri P, Kaur I. Exploring the involvement of the alternative complement pathway in non-infectious uveitis pathogenesis. Front Immunol 2023; 14:1222998. [PMID: 38187376 PMCID: PMC10768558 DOI: 10.3389/fimmu.2023.1222998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 11/20/2023] [Indexed: 01/09/2024] Open
Abstract
Purpose Non-infectious uveitis is a complex disease characterized by intraocular inflammation of the uveal area and the leading cause of vision impairment and blindness in young people globally. However, what triggers inflammation and contributes to its recurrence remains unclear. The complement system has been linked to various immunological and inflammatory conditions. In the present study, we have systematically evaluated the role of the alternative complement pathway in the pathogenesis of non-infectious uveitis. Methodology Quantitative PCR was done in the peripheral leukocytes to study the expression of genes and regulatory miRNA in both anterior and posterior uveitis (n=28 in each category). Multiplex ELISA was performed to measure alternative pathway complement components, such as C3b, factor B, and CFH, and aqueous humor of infectious and non-infectious uveitis patients and non-inflammatory controls (n=10 each). Western blotting was done to validate the ELISA findings in a subset of patients and controls. Results Downregulation of C3 and CFH mRNA in the peripheral blood was shown by quantitative PCR in the group of anterior uveiits (AU), while the opposite result was found in the group of posterior uveitis (PU). ELISA levels of C3b and CFH proteins were significantly higher in aqueous humor of infectious and non-infectious uveitis (*p = 0.03 and **p = 0.0007 respectively) as compared to the control group. Western blotting further validated (VitH) the activation of the complement cascade in the aqueous (AH) and vitreous humor of patients with non-infectious uveitis, with an increased level of C3b (n=6) and CFH (n=4) in aqueous humor. C3b level was significantly increased while CFH was reduced relative to controls in the vitreous humor (VitH) of posterior uveitis patients compared to controls (n=27 in each category). A C3b to CFH ratio was computed to assess the regulation of complement activation and this index was several folds higher in both anterior and posterior uveitis (n=10 each). The expression of miRNA-hsa-miR-146a and miRNA-hsa-miR-155-5p that regulates CFH was downregulated and nicely correlated with the increased complement proteins in both anterior and posterior uveitis (n=10 each). Conclusion Our results demonstrate a clear role of CFH and the activation of the alternative complement pathway in the pathogenesis of non-infectious uveitis; however, its therapeutic potential warrants further investigations.
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Affiliation(s)
- Prerna Kulshrestha
- Prof. Brien Holden Eye Research Centre, L. V. Prasad Eye Institute, Hyderabad, India
- School of Life Science, Manipal Academy of Higher Education, Manipal, India
| | - Pallavi Goel
- Prof. Brien Holden Eye Research Centre, L. V. Prasad Eye Institute, Hyderabad, India
| | - Somasheila Murthy
- Shantilal Shanghvi Cornea Institute, L. V. Prasad Eye Institute, Hyderabad, India
| | - Mudit Tyagi
- Smt. Kannuri Santhamma Centre for Vitreo Retinal Diseases, L. V. Prasad Eye Institute, Hyderabad, India
| | - Soumvaya Basu
- Smt. Kannuri Santhamma Centre for Vitreo Retinal Diseases, L. V. Prasad Eye Institute, Hyderabad, India
| | - Pratik Gogri
- Shantilal Shanghvi Cornea Institute, L. V. Prasad Eye Institute, Hyderabad, India
| | - Inderjeet Kaur
- Prof. Brien Holden Eye Research Centre, L. V. Prasad Eye Institute, Hyderabad, India
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Hammadi S, Tzoumas N, Ferrara M, Meschede IP, Lo K, Harris C, Lako M, Steel DH. Bruch's Membrane: A Key Consideration with Complement-Based Therapies for Age-Related Macular Degeneration. J Clin Med 2023; 12:2870. [PMID: 37109207 PMCID: PMC10145879 DOI: 10.3390/jcm12082870] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 03/29/2023] [Accepted: 04/03/2023] [Indexed: 04/29/2023] Open
Abstract
The complement system is crucial for immune surveillance, providing the body's first line of defence against pathogens. However, an imbalance in its regulators can lead to inappropriate overactivation, resulting in diseases such as age-related macular degeneration (AMD), a leading cause of irreversible blindness globally affecting around 200 million people. Complement activation in AMD is believed to begin in the choriocapillaris, but it also plays a critical role in the subretinal and retinal pigment epithelium (RPE) spaces. Bruch's membrane (BrM) acts as a barrier between the retina/RPE and choroid, hindering complement protein diffusion. This impediment increases with age and AMD, leading to compartmentalisation of complement activation. In this review, we comprehensively examine the structure and function of BrM, including its age-related changes visible through in vivo imaging, and the consequences of complement dysfunction on AMD pathogenesis. We also explore the potential and limitations of various delivery routes (systemic, intravitreal, subretinal, and suprachoroidal) for safe and effective delivery of conventional and gene therapy-based complement inhibitors to treat AMD. Further research is needed to understand the diffusion of complement proteins across BrM and optimise therapeutic delivery to the retina.
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Affiliation(s)
- Sarah Hammadi
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Nikolaos Tzoumas
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- Sunderland Eye Infirmary, Queen Alexandra Rd., Sunderland SR2 9H, UK
| | | | - Ingrid Porpino Meschede
- Gyroscope Therapeutics Limited, a Novartis Company, Rolling Stock Yard, 6th Floor, 188 York Way, London N7 9AS, UK
| | - Katharina Lo
- Gyroscope Therapeutics Limited, a Novartis Company, Rolling Stock Yard, 6th Floor, 188 York Way, London N7 9AS, UK
| | - Claire Harris
- Gyroscope Therapeutics Limited, a Novartis Company, Rolling Stock Yard, 6th Floor, 188 York Way, London N7 9AS, UK
- Clinical and Translational Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Majlinda Lako
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - David H. Steel
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- Sunderland Eye Infirmary, Queen Alexandra Rd., Sunderland SR2 9H, UK
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Wang Y, Shen H, Pang L, Qiu B, Yuan Y, Guan X, Xiang X. Qihuang Granule protects the retinal pigment epithelium from oxidative stress via regulation of the alternative complement pathway. BMC Complement Med Ther 2023; 23:55. [PMID: 36800952 PMCID: PMC9938598 DOI: 10.1186/s12906-023-03884-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 02/13/2023] [Indexed: 02/20/2023] Open
Abstract
BACKGROUND Age-related macular degeneration (AMD) is a leading cause of vision loss in elderly people, and dry AMD is the most common type of AMD. Oxidative stress and alternative complement pathway activation may play essential roles in the pathogenesis of dry AMD. There are no available drugs for dry AMD. Qihuang Granule (QHG) is an herbal formula for the treatment of dry AMD, and it achieves a good clinical effect in our hospital. However, its potential mechanism is unclear. Our study investigated the effects of QHG on oxidative stress-associated retinal damage to reveal its underlying mechanism. METHODS Oxidative stress models were established using H2O2 and NaIO3 in ARPE-19 cells and C57BL/6 mice. Cell apoptosis and viability were assessed using phase contrast microscopy and flow cytometry, respectively. Alterations in the mouse retinal structure were evaluated using Masson staining and transmission electron microscopy (TEM). The expression of complement factor H (CFH), complement component 3a (C3a) and complement component 5a (C5a) in retinal pigment epithelium (RPE) cells and mice was measured using RT‒PCR, Western blot analysis and ELISA. RESULTS Pretreatment with QHG significantly prevented cell apoptosis and disorder of the RPE and inner segment/outer segment (IS/OS) in H2O2-treated RPE cells and NaIO3-injected mice. QHG alleviated mitochondrial damage in mouse RPE cells, as shown by TEM. QHG also promoted CFH expression and inhibited the expression of C3a and C5a. CONCLUSIONS The results suggest that QHG protects the retinal pigment epithelium from oxidative stress, likely by regulating the alternative complement pathway.
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Affiliation(s)
- Yan Wang
- Department of Ophthalmology, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, 111 Dade Road, Guangzhou, 510120, China.
| | - Huangxuan Shen
- grid.12981.330000 0001 2360 039XState Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlie Road, Guangzhou, 510060 China
| | - Long Pang
- grid.411866.c0000 0000 8848 7685Department of Ophthalmology, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, 111 Dade Road, Guangzhou, 510120 China
| | - Bo Qiu
- grid.411866.c0000 0000 8848 7685Department of Ophthalmology, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, 111 Dade Road, Guangzhou, 510120 China
| | - Yuan Yuan
- grid.411866.c0000 0000 8848 7685Department of Ophthalmology, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, 111 Dade Road, Guangzhou, 510120 China
| | - Xiaoying Guan
- grid.411866.c0000 0000 8848 7685The Second Clinical college of Guangzhou University of Chinese Medicine, Guangzhou, 510006 China
| | - Xiaolan Xiang
- grid.411866.c0000 0000 8848 7685The Second Clinical college of Guangzhou University of Chinese Medicine, Guangzhou, 510006 China
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Ormenişan DM, Borda A. Benefits of genetic and immunohistochemical markers in understanding abnormalities in aging retina. ROMANIAN JOURNAL OF MORPHOLOGY AND EMBRYOLOGY = REVUE ROUMAINE DE MORPHOLOGIE ET EMBRYOLOGIE 2022; 63:121-127. [PMID: 36074675 PMCID: PMC9593114 DOI: 10.47162/rjme.63.1.12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 06/10/2022] [Indexed: 06/15/2023]
Abstract
The aim of the study was to better understand the interplay between genetic factors and the aging process in the human retina through mapping complement factor H (CFH) and related proteins. Two human eyes, from 92- and 64-year-old donors, were genotyped for the expression of CFH-related 1 (CFHR1) and CFH-related 3 (CFHR3) genes. Deoxyribonucleic acid (DNA) was extracted and analyzed for concentration and purity with a spectrophotometer, at 260 nm. The results showed a DNA concentration of 469.17 ng∕μL in the aged retina and of 399.20 ng∕μL in the younger one. Through polymerase chain reaction (PCR) genotyping, the DNA CFHR1 and CFHR3 were visible as bands of 175 bp and 181 bp. Immunohistochemistry by immunofluorescence method was used with a panel of specific antibodies for CFH, CFHR1, CFHR3 and GFAP, a marker for Müller cells. All the samples were examined, and images captured using confocal microscopy. In the younger retina, CFH was localized in the inner plexiform layer and below the outer nuclear layer, while in the aged retina, it was found in the photoreceptors. CFH was also detected in the choriocapillaris and within the end-feet of the Müller cells. Our controls showed autofluorescence of the retinal pigment epithelium shedding light on a false positive CFH immunostaining of this layer. GFAP immunoreactivity highlighted an increased gliosis within the aged retina. CFHR3 signal was found in the microglia, while CFHR1 was detected in the choriocapillaris. In summary, underpinning the expression of these components can show the potential involvement of these modulators in implementing new treatment strategies.
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Scaffold-Free Retinal Pigment Epithelium Microtissues Exhibit Increased Release of PEDF. Int J Mol Sci 2021; 22:ijms222111317. [PMID: 34768747 PMCID: PMC8583603 DOI: 10.3390/ijms222111317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/14/2021] [Accepted: 10/16/2021] [Indexed: 12/26/2022] Open
Abstract
The retinal pigmented epithelium (RPE) plays a critical role in photoreceptor survival and function. RPE deficits are implicated in a wide range of diseases that result in vision loss, including age-related macular degeneration (AMD) and Stargardt disease, affecting millions worldwide. Subretinal delivery of RPE cells is considered a promising avenue for treatment, and encouraging results from animal trials have supported recent progression into the clinic. However, the limited survival and engraftment of transplanted RPE cells delivered as a suspension continues to be a major challenge. While RPE delivery as epithelial sheets exhibits improved outcomes, this comes at the price of increased complexity at both the production and transplant stages. In order to combine the benefits of both approaches, we have developed size-controlled, scaffold-free RPE microtissues (RPE-µTs) that are suitable for scalable production and delivery via injection. RPE-µTs retain key RPE molecular markers, and interestingly, in comparison to conventional monolayer cultures, they show significant increases in the transcription and secretion of pigment-epithelium-derived factor (PEDF), which is a key trophic factor known to enhance the survival and function of photoreceptors. Furthermore, these microtissues readily spread in vitro on a substrate analogous to Bruch’s membrane, suggesting that RPE-µTs may collapse into a sheet upon transplantation. We anticipate that this approach may provide an alternative cell delivery system to improve the survival and integration of RPE transplants, while also retaining the benefits of low complexity in production and delivery.
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8
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Bonilha VL, Bell BA, Hu J, Milliner C, Pauer GJ, Hagstrom SA, Radu RA, Hollyfield JG. Geographic Atrophy: Confocal Scanning Laser Ophthalmoscopy, Histology, and Inflammation in the Region of Expanding Lesions. Invest Ophthalmol Vis Sci 2021; 61:15. [PMID: 32658960 PMCID: PMC7425718 DOI: 10.1167/iovs.61.8.15] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Purpose To describe the pathology of AMD in eyes with geographic atrophy (GA) using confocal scanning laser ophthalmoscopy (SLO) blue light autofluorescence (BAF), and near-infrared (IR) AF and to correlate it with the histology and immunohistochemistry analysis at the margins of the GA lesion. Methods Enucleated, fixed eyes from seventeen donors with GA were imaged and analyzed by BAF-SLO, IRAF-SLO, and by fundus macroscopy (FM). Tissue from the margins of the GA lesions was cut and processed for resin embedding and histology or cryosectioning and fluorescence in the green and far-red channels, and immunohistochemistry to assess markers of inflammation. Isolated DNA from donors was genotyped for single nucleotide polymorphisms (SNPs) previously shown to be risk factors for the development and progression of AMD. Results Around the leading edge of the GA lesions we observed hypertrophic RPE cells with cytoplasm filled with granules fluorescent both in the far-red and green-red channels; abundant microglia and macrophage; deposition of complement factor H (CFH) in Bruch's membrane (BM) and increased membrane attack complex (MAC) on RPE cells. Conclusions Fluorescence imaging of cryosections of RPE cells around the leading edge of the GA lesions suggest that IRAF-SLO visualizes mostly melanin-related compounds. In addition, medium-size GA atrophy displayed the most significant changes in inflammation markers.
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9
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Single-cell RNA sequencing in vision research: Insights into human retinal health and disease. Prog Retin Eye Res 2020; 83:100934. [PMID: 33383180 DOI: 10.1016/j.preteyeres.2020.100934] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 11/27/2020] [Accepted: 12/01/2020] [Indexed: 01/03/2023]
Abstract
Gene expression provides valuable insight into cell function. As such, vision researchers have frequently employed gene expression studies to better understand retinal physiology and disease. With the advent of single-cell RNA sequencing, expression experiments provide an unparalleled resolution of information. Instead of studying aggregated gene expression across all cells in a heterogenous tissue, single-cell technology maps RNA to an individual cell, which facilitates grouping of retinal and choroidal cell types for further study. Single-cell RNA sequencing has been quickly adopted by both basic and translational vision researchers, and single-cell level gene expression has been studied in the visual systems of animal models, retinal organoids, and primary human retina, RPE, and choroid. These experiments have generated detailed atlases of gene expression and identified new retinal cell types. Likewise, single-cell RNA sequencing investigations have characterized how gene expression changes in the setting of many retinal diseases, including how choroidal endothelial cells are altered in age-related macular degeneration. In addition, this technology has allowed vision researchers to discover drivers of retinal development and model rare retinal diseases with induced pluripotent stem cells. In this review, we will overview the growing number of single-cell RNA sequencing studies in the field of vision research. We will summarize experimental considerations for designing single-cell RNA sequencing experiments and highlight important advancements in retinal, RPE, choroidal, and retinal organoid biology driven by this technology. Finally, we generalize these findings to genes involved in retinal degeneration and outline the future of single-cell expression experiments in studying retinal disease.
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10
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Tzoumas N, Hallam D, Harris CL, Lako M, Kavanagh D, Steel DHW. Revisiting the role of factor H in age-related macular degeneration: Insights from complement-mediated renal disease and rare genetic variants. Surv Ophthalmol 2020; 66:378-401. [PMID: 33157112 DOI: 10.1016/j.survophthal.2020.10.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 10/27/2020] [Accepted: 10/29/2020] [Indexed: 12/14/2022]
Abstract
Ophthalmologists are long familiar with the eye showing signs of systemic disease, but the association between age-related macular degeneration and abnormal complement activation, common to several renal disorders, has only recently been elucidated. Although complement activation products were identified in drusen almost three decades ago, it was not until the early 21st century that a single-nucleotide polymorphism in the complement factor H gene was identified as a major heritable determinant of age-related macular degeneration, galvanizing global efforts to unravel the pathogenesis of this common disease. Advances in proteomic analyses and familial aggregation studies have revealed distinctive clinical phenotypes segregated by the functional effects of common and rare genetic variants on the mature protein and its splice variant, factor H-like protein 1. The predominance of loss-of-function, N-terminal mutations implicate age-related macular degeneration as a disease of general complement dysregulation, offering several therapeutic avenues for its modulation. Here, we explore the molecular impact of these mutations/polymorphisms on the ability of variant factor H/factor H-like protein 1 to localize to polyanions, pentraxins, proinflammatory triggers, and cell surfaces across ocular and renal tissues and exert its multimodal regulatory functions and their clinical implications. Finally, we critically evaluate key therapeutic and diagnostic efforts in this rapidly evolving field.
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Affiliation(s)
- Nikolaos Tzoumas
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom.
| | - Dean Hallam
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Claire L Harris
- Complement Therapeutics Research Group, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom; National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
| | - Majlinda Lako
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - David Kavanagh
- Complement Therapeutics Research Group, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom; National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
| | - David H W Steel
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom; Sunderland Eye Infirmary, Sunderland, United Kingdom
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11
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Al-Ani A, Sunba S, Hafeez B, Toms D, Ungrin M. In Vitro Maturation of Retinal Pigment Epithelium Is Essential for Maintaining High Expression of Key Functional Genes. Int J Mol Sci 2020; 21:ijms21176066. [PMID: 32842471 PMCID: PMC7503905 DOI: 10.3390/ijms21176066] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/08/2020] [Accepted: 08/19/2020] [Indexed: 12/03/2022] Open
Abstract
Age-related macular degeneration (AMD) is the leading cause of blindness in the industrialized world. AMD is associated with dysfunction and atrophy of the retinal pigment epithelium (RPE), which provides critical support for photoreceptor survival and function. RPE transplantation is a promising avenue towards a potentially curative treatment for early stage AMD patients, with encouraging reports from animal trials supporting recent progression toward clinical treatments. Mature RPE cells have been reported to be superior, but a detailed investigation of the specific changes in the expression pattern of key RPE genes during maturation is lacking. To understand the effect of maturity on RPE, we investigated transcript levels of 19 key RPE genes using ARPE-19 cell line and human embryonic stem cell-derived RPE cultures. Mature RPE cultures upregulated PEDF, IGF-1, CNTF and BDNF—genes that code for trophic factors known to enhance the survival and function of photoreceptors. Moreover, the mRNA levels of these genes are maximized after 42 days of maturation in culture and lost upon dissociation to single cells. Our findings will help to inform future animal and human RPE transplantation efforts.
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Affiliation(s)
- Abdullah Al-Ani
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB T2N 1N4, Canada; (A.A.-A.); (S.S.); (B.H.); (M.U.)
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB T6G 2E1, Canada
- Biomedical Engineering Graduate Program, University of Calgary, Calgary, AB T2N 1N4, Canada
- Leaders in Medicine Program, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Saud Sunba
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB T2N 1N4, Canada; (A.A.-A.); (S.S.); (B.H.); (M.U.)
| | - Bilal Hafeez
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB T2N 1N4, Canada; (A.A.-A.); (S.S.); (B.H.); (M.U.)
| | - Derek Toms
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB T2N 1N4, Canada; (A.A.-A.); (S.S.); (B.H.); (M.U.)
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
- Correspondence:
| | - Mark Ungrin
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB T2N 1N4, Canada; (A.A.-A.); (S.S.); (B.H.); (M.U.)
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB T6G 2E1, Canada
- Biomedical Engineering Graduate Program, University of Calgary, Calgary, AB T2N 1N4, Canada
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12
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Abokyi S, To CH, Lam TT, Tse DY. Central Role of Oxidative Stress in Age-Related Macular Degeneration: Evidence from a Review of the Molecular Mechanisms and Animal Models. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:7901270. [PMID: 32104539 PMCID: PMC7035553 DOI: 10.1155/2020/7901270] [Citation(s) in RCA: 100] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Accepted: 01/18/2020] [Indexed: 11/17/2022]
Abstract
Age-related macular degeneration (AMD) is a common cause of visual impairment in the elderly. There are very limited therapeutic options for AMD with the predominant therapies targeting vascular endothelial growth factor (VEGF) in the retina of patients afflicted with wet AMD. Hence, it is important to remind readers, especially those interested in AMD, about current studies that may help to develop novel therapies for other stages of AMD. This study, therefore, provides a comprehensive review of studies on human specimens as well as rodent models of the disease, to identify and analyze the molecular mechanisms behind AMD development and progression. The evaluation of this information highlights the central role that oxidative damage in the retina plays in contributing to major pathways, including inflammation and angiogenesis, found in the AMD phenotype. Following on the debate of oxidative stress as the earliest injury in the AMD pathogenesis, we demonstrated how the targeting of oxidative stress-associated pathways, such as autophagy and nuclear factor erythroid 2-related factor 2 (Nrf2) signaling, might be the futuristic direction to explore in the search of an effective treatment for AMD, as the dysregulation of these mechanisms is crucial to oxidative injury in the retina. In addition, animal models of AMD have been discussed in great detail, with their strengths and pitfalls included, to assist inform in the selection of suitable models for investigating any of the molecular mechanisms.
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Affiliation(s)
- Samuel Abokyi
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong
- Department of Optometry, University of Cape Coast, Ghana
| | - Chi-Ho To
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong
| | - Tim T. Lam
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong
| | - Dennis Y. Tse
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong
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13
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Valencia E, Cruz-Alonso M, Álvarez L, González-Iglesias H, Fernández B, Pereiro R. Fluorescent silver nanoclusters as antibody label in a competitive immunoassay for the complement factor H. Mikrochim Acta 2019; 186:429. [DOI: 10.1007/s00604-019-3554-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 05/24/2019] [Indexed: 10/26/2022]
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14
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Afarid M, Azimi A, Malekzadeh M. Evaluation of serum interferons in patients with age-related macular degeneration. JOURNAL OF RESEARCH IN MEDICAL SCIENCES 2019; 24:24. [PMID: 31007694 PMCID: PMC6450131 DOI: 10.4103/jrms.jrms_363_18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/16/2018] [Accepted: 12/25/2018] [Indexed: 12/15/2022]
Abstract
Background: Environmental, genetic, and immunological factors may play a role in the pathogenesis of age-related macular degeneration (AMD). In an attempt to better understand the pathogenesis of AMD, in this study, we evaluated the serum interferon (IFN) levels in patients with AMD and compared it with persons without AMD. Materials and Methods: In this case–control study, 42 patients with AMD and 42 healthy individuals (without AMD) were enrolled as the case and control groups, respectively. The two groups were matched regarding their age and sex. We classified the case group as dry-type and wet-type AMD. Blood samples were obtained and the serum was collected and frozen at −20°C. Alpha-, beta-, and gamma-IFN levels were measured using the sandwich ELISA method and compared between and within the groups. Results: The mean beta IFN levels in both case and control groups were 46.88 ± 27.25 pg/ml and 34.90 ± 18.81 pg/ml (P = 0.021), respectively. Regarding gamma and alpha IFN, the serum levels were not detectable in most of the patients and no significant difference was detected between the case and control groups. Conclusion: We found that serum beta IFN levels are higher in patients with AMD. This finding may have diagnostic, therapeutic, and prognostic value in AMD patients and can be a beginning for further evaluation.
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Affiliation(s)
- Mehrdad Afarid
- Department of Ophthalmology, Poostchi Ophthalmology Research Center, Shiraz Medical School, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Ali Azimi
- Department of Ophthalmology, Poostchi Ophthalmology Research Center, Shiraz Medical School, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mahyar Malekzadeh
- School of Medicine, Shiraz Institute for Cancer Research, Shiraz University of Medical Sciences, Shiraz, Iran
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15
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Chen X, Li L, Liu F, Hoh J, Kapron CM, Liu J. Cadmium Induces Glomerular Endothelial Cell–Specific Expression of Complement Factor H via the −1635 AP-1 Binding Site. THE JOURNAL OF IMMUNOLOGY 2019; 202:1210-1218. [DOI: 10.4049/jimmunol.1800081] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 12/13/2018] [Indexed: 02/06/2023]
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16
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On the origin of proteins in human drusen: The meet, greet and stick hypothesis. Prog Retin Eye Res 2018; 70:55-84. [PMID: 30572124 DOI: 10.1016/j.preteyeres.2018.12.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 12/11/2018] [Accepted: 12/12/2018] [Indexed: 12/12/2022]
Abstract
Retinal drusen formation is not only a clinical hallmark for the development of age-related macular degeneration (AMD) but also for other disorders, such as Alzheimer's disease and renal diseases. The initiation and growth of drusen is poorly understood. Attention has focused on lipids and minerals, but relatively little is known about the origin of drusen-associated proteins and how they are retained in the space between the basal lamina of the retinal pigment epithelium and the inner collagenous layer space (sub-RPE-BL space). While some authors suggested that drusen proteins are mainly derived from cellular debris from processed photoreceptor outer segments and the RPE, others suggest a choroidal cell or blood origin. Here, we reviewed and supplemented the existing literature on the molecular composition of the retina/choroid complex, to gain a more complete understanding of the sources of proteins in drusen. These "drusenomics" studies showed that a considerable proportion of currently identified drusen proteins is uniquely originating from the blood. A smaller, but still large fraction of drusen proteins comes from both blood and/or RPE. Only a small proportion of drusen proteins is uniquely derived from the photoreceptors or choroid. We next evaluated how drusen components may "meet, greet and stick" to each other and/or to structures like hydroxyapatite spherules to form macroscopic deposits in the sub-RPE-BL space. Finally, we discuss implications of our findings with respect to the previously proposed homology between drusenogenesis in AMD and plaque formation in atherosclerosis.
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17
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Hazim RA, Volland S, Yen A, Burgess BL, Williams DS. Rapid differentiation of the human RPE cell line, ARPE-19, induced by nicotinamide. Exp Eye Res 2018; 179:18-24. [PMID: 30336127 DOI: 10.1016/j.exer.2018.10.009] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 09/17/2018] [Accepted: 10/13/2018] [Indexed: 12/31/2022]
Abstract
Human RPE cell lines, especially the ARPE-19 cell line, are widely-used in eye research, as well as general epithelial cell studies. In comparison with primary RPE cells, they offer relative convenience and consistency, but cultures derived from these lines are typically not well differentiated. We describe a simple, rapid method to establish cultures from ARPE-19 cells, with significantly improved epithelial cell morphology and cytoskeletal organization, and RPE-related functions. We identify the presence of nicotinamide, a member of the vitamin B family, as an essential factor in promoting the observed differentiation, indicating the importance of metabolism in RPE cell differentiation.
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Affiliation(s)
- Roni A Hazim
- Department of Ophthalmology and Stein Eye Institute, University of California, Los Angeles, CA, USA
| | - Stefanie Volland
- Department of Ophthalmology and Stein Eye Institute, University of California, Los Angeles, CA, USA
| | - Alice Yen
- Department of Ophthalmology and Stein Eye Institute, University of California, Los Angeles, CA, USA
| | - Barry L Burgess
- Department of Ophthalmology and Stein Eye Institute, University of California, Los Angeles, CA, USA
| | - David S Williams
- Department of Ophthalmology and Stein Eye Institute, University of California, Los Angeles, CA, USA; Department of Neurobiology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA, USA; Molecular Biology Institute, University of California, Los Angeles, CA, USA; Brain Research Institute, University of California, Los Angeles, CA, USA.
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18
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Jeong HS, Yun JH, Lee DH, Lee EH, Cho CH. Retinal pigment epithelium-derived transforming growth factor-β2 inhibits the angiogenic response of endothelial cells by decreasing vascular endothelial growth factor receptor-2 expression. J Cell Physiol 2018; 234:3837-3849. [PMID: 30256387 DOI: 10.1002/jcp.27156] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 07/10/2018] [Indexed: 12/25/2022]
Abstract
Transforming growth factor-β (TGF-β) is a multifunctional cytokine that is known to modulate various aspects of endothelial cell (EC) biology. Retinal pigment epithelium (RPE) is important for regulating angiogenesis of choriocapillaris and one of the main cell sources of TGF-β secretion, particularly TGF-β2. However, it is largely unclear whether and how TGF-β2 affects angiogenic responses of ECs. In the current study, we demonstrated that TGF-β2 reduces vascular endothelial growth factor receptor-2 (VEGFR-2) expression in ECs and thereby inhibits vascular endothelial growth factor (VEGF) signaling and VEGF-induced angiogenic responses such as EC migration and tube formation. We also demonstrated that the reduction of VEGFR-2 expression by TGF-β2 is due to the suppression of JNK signaling. In coculture of RPE cells and ECs, RPE cells decreased VEGFR-2 levels in ECs and EC migration. In addition, we showed that TGF-β2 derived from RPE cells is involved in the reduction of VEGFR-2 expression and inhibition of EC migration. These results suggest that TGF-β2 plays an important role in inhibiting the angiogenic responses of ECs during the interaction between RPE cells and ECs and that angiogenic responses of ECs may be amplified by a decrease in TGF-β2 expression in RPE cells under pathologic conditions.
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Affiliation(s)
- Han-Seok Jeong
- Vascular Microenvironment Laboratory, Department of Pharmacology and Ischemic/Hypoxic Disease Institute, College of Medicine, Seoul National University, Seoul, Korea.,Department of Biomedical Sciences, College of Medicine, Seoul National University, Seoul, Korea
| | - Jang-Hyuk Yun
- Vascular Microenvironment Laboratory, Department of Pharmacology and Ischemic/Hypoxic Disease Institute, College of Medicine, Seoul National University, Seoul, Korea
| | - Da-Hye Lee
- Vascular Microenvironment Laboratory, Department of Pharmacology and Ischemic/Hypoxic Disease Institute, College of Medicine, Seoul National University, Seoul, Korea.,Department of Biomedical Sciences, College of Medicine, Seoul National University, Seoul, Korea
| | - Eun Hui Lee
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Chung-Hyun Cho
- Vascular Microenvironment Laboratory, Department of Pharmacology and Ischemic/Hypoxic Disease Institute, College of Medicine, Seoul National University, Seoul, Korea.,Department of Biomedical Sciences, College of Medicine, Seoul National University, Seoul, Korea.,Cancer Research Institute, College of Medicine, Seoul National University, Seoul, Korea
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19
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Pao PJ, Emri E, Abdirahman SB, Soorma T, Zeng HH, Hauck SM, Thompson RB, Lengyel I. The effects of zinc supplementation on primary human retinal pigment epithelium. J Trace Elem Med Biol 2018. [PMID: 29523386 DOI: 10.1016/j.jtemb.2018.02.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Population-based and interventional studies have shown that elevated zinc levels can reduce the progression to advanced age-related macular degeneration. The objective of this study was to assess whether elevated extracellular zinc has a direct effect on retinal pigment epithelial cells (RPE), by examining the phenotype and molecular characteristics of increased extracellular zinc on human primary RPE cells. Monolayers of human foetal primary RPE cells were grown on culture inserts and maintained in medium supplemented with increasing total concentrations of zinc (0, 75, 100, 125 and 150 μM) for up to 4 weeks. Changes in cell viability and differentiation as well as expression and secretion of proteins were investigated. RPE cells developed a confluent monolayer with cobblestone morphology and transepithelial resistance (TER) >200 Ω*cm2 within 4 weeks. There was a zinc concentration-dependent increase in TER and pigmentation, with the largest effects being achieved by the addition of 125 μM zinc to the culture medium, corresponding to 3.4 nM available (free) zinc levels. The cells responded to addition of zinc by significantly increasing the expression of Retinoid Isomerohydrolase (RPE65) gene; cell pigmentation; Premelanosome Protein (PMEL17) immunoreactivity; and secretion of proteins including Apolipoprotein E (APOE), Complement Factor H (CFH), and High-Temperature Requirement A Serine Peptidase 1 (HTRA1) without an effect on cell viability. This study shows that elevated extracellular zinc levels have a significant and direct effect on differentiation and function of the RPE cells in culture, which may explain, at least in part, the positive effects seen in clinical settings. The results also highlight that determining and controlling of available, as opposed to total added, zinc will be essential to be able to compare results obtained in different laboratories.
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Affiliation(s)
- Po-Jung Pao
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, 11-43 Bath St, London EC1 V9EL, United Kingdom; Department of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom.
| | - Eszter Emri
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, 11-43 Bath St, London EC1 V9EL, United Kingdom; Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University, 97 Lisburn Road, Belfast, BT9 7BL, Northern Ireland, United Kingdom.
| | - Safiya Bishar Abdirahman
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, 11-43 Bath St, London EC1 V9EL, United Kingdom.
| | - Talha Soorma
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, 11-43 Bath St, London EC1 V9EL, United Kingdom.
| | - Hui-Hui Zeng
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene Street, Baltimore, MD 21201, United States.
| | - Stefanie M Hauck
- Research Unit Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health(GmbH), Ingolstädter Landstraße 1, 85764 Oberschleißheim, Germany.
| | - Richard B Thompson
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene Street, Baltimore, MD 21201, United States.
| | - Imre Lengyel
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, 11-43 Bath St, London EC1 V9EL, United Kingdom; Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University, 97 Lisburn Road, Belfast, BT9 7BL, Northern Ireland, United Kingdom.
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20
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Arya S, Emri E, Synowsky SA, Shirran SL, Barzegar-Befroei N, Peto T, Botting CH, Lengyel I, Stewart AJ. Quantitative analysis of hydroxyapatite-binding plasma proteins in genotyped individuals with late-stage age-related macular degeneration. Exp Eye Res 2018; 172:21-29. [DOI: 10.1016/j.exer.2018.03.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 03/16/2018] [Accepted: 03/22/2018] [Indexed: 12/17/2022]
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21
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Schnabolk G, Parsons N, Obert E, Annamalai B, Nasarre C, Tomlinson S, Lewin AS, Rohrer B. Delivery of CR2-fH Using AAV Vector Therapy as Treatment Strategy in the Mouse Model of Choroidal Neovascularization. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2017; 9:1-11. [PMID: 29234687 PMCID: PMC5723362 DOI: 10.1016/j.omtm.2017.11.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 11/06/2017] [Indexed: 12/12/2022]
Abstract
Complement activation plays a significant role in age-related macular degeneration (AMD) pathogenesis, and polymorphisms interfering with factor H (fH) function, a complement alternative pathway (AP) inhibitor, are associated with increased AMD risk. We have previously validated an AP inhibitor, a fusion protein consisting of a complement receptor 2 fragment linked to the inhibitory domain of fH (CR2-fH) as an efficacious treatment for choroidal neovascularization (CNV) when delivered intravenously. Here we tested an alternative approach of AAV-mediated delivery (AAV5-VMD2-CR2-fH or AAV5-VMD2-mCherry) using subretinal delivery in C57BL/6J mice. Secretion of CR2-fH was confirmed in polarized retinal pigment epithelium (RPE) cells. A safe concentration of AAV5-VMD2-CR2-fH was identified using electroretinography, optical coherence tomography (OCT), RPE morphology, and antibody profiling. One month after gene delivery, CNV was induced using argon laser photocoagulation. OCT assessment demonstrated reduced CNV with AAV5-VMD2-CR2-fH administration. Bioavailability studies revealed that gene-therapy delivered similar levels of CR2-fH to the RPE/choroid as treatment by intravenous injections, and C3a ELISA verified reduced CNV-associated ocular C3a production. These results contribute to existing data illustrating the importance of the AP of complement in CNV development and its potential role in AMD treatment. Demonstration of AAV-vector efficacy opens new avenues for the development of treatment strategies.
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Affiliation(s)
- Gloriane Schnabolk
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Nathaniel Parsons
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Elisabeth Obert
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA
| | | | - Cecile Nasarre
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Stephen Tomlinson
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC 29425, USA.,Ralph H. Johnson VA Medical Center, Division of Research, Charleston, SC 29401, USA
| | - Alfred S Lewin
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville FL 32611, USA
| | - Bärbel Rohrer
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA.,Ralph H. Johnson VA Medical Center, Division of Research, Charleston, SC 29401, USA
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22
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Liu J, Hoh J. Loss of Complement Factor H in Plasma Increases Endothelial Cell Migration. J Cancer 2017; 8:2184-2190. [PMID: 28819420 PMCID: PMC5560135 DOI: 10.7150/jca.19452] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 04/22/2017] [Indexed: 02/06/2023] Open
Abstract
Tumor growth depends on angiogenesis, the growth of new blood vessels. Complement factor H (CFH) is a plasma glycoprotein that functions as a regulator of the complement system. The aim of this study is to delineate the role of CFH in angiogenesis. A conditional null allele of the Cfh gene was generated in C57BL/6J mice by flanking the exon 3 with loxP sites. The Cfhflox/flox mice were crossed with Rosa26-Cre mice to obtain the mice homozygotes of Cfh deletion (Cfh-/-). The Cfh-/- mice were examined by in vivo angiogenesis assays. Mouse endothelial cells were treated with media containing 5% of mouse plasma from the wildtype or Cfh-/- mice and assayed for proliferation, viability and migration. The Cfh-/- mice did not display any obvious abnormalities. They demonstrated a pro-angiogenic phenotype in matrigel plug assay, but not in aorta ring assay. In vitro, loss of Cfh in plasma does not affect proliferation or viability, but significantly increases migration of mouse endothelial cells. Our findings suggest that plasma CFH inhibits angiogenesis by reduction of endothelial cell migration. Thus the mutation of CFH might lead to excessive tumor angiogenesis.
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Affiliation(s)
- Ju Liu
- Medical Research Center, Shandong Provincial Qianfoshan Hospital, Shandong University, 16766 Jingshi Road, Jinan, Shandong China 250014
| | - Josephine Hoh
- Department of Epidemiology and Public Health, Yale University, 60 College Street, New Haven, CT 06520, USA
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23
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The impact of oxidative stress and inflammation on RPE degeneration in non-neovascular AMD. Prog Retin Eye Res 2017; 60:201-218. [PMID: 28336424 DOI: 10.1016/j.preteyeres.2017.03.002] [Citation(s) in RCA: 478] [Impact Index Per Article: 68.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 03/13/2017] [Accepted: 03/14/2017] [Indexed: 02/07/2023]
Abstract
The retinal pigment epithelium (RPE) is a highly specialized, unique epithelial cell that interacts with photoreceptors on its apical side and with Bruch's membrane and the choriocapillaris on its basal side. Due to vital functions that keep photoreceptors healthy, the RPE is essential for maintaining vision. With aging and the accumulated effects of environmental stresses, the RPE can become dysfunctional and die. This degeneration plays a central role in age-related macular degeneration (AMD) pathobiology, the leading cause of blindness among the elderly in western societies. Oxidative stress and inflammation have both physiological and potentially pathological roles in RPE degeneration. Given the central role of the RPE, this review will focus on the impact of oxidative stress and inflammation on the RPE with AMD pathobiology. Physiological sources of oxidative stress as well as unique sources from photo-oxidative stress, the phagocytosis of photoreceptor outer segments, and modifiable factors such as cigarette smoking and high fat diet ingestion that can convert oxidative stress into a pathological role, and the negative impact of impairing the cytoprotective roles of mitochondrial dynamics and the Nrf2 signaling system on RPE health in AMD will be discussed. Likewise, the response by the innate immune system to an inciting trigger, and the potential role of local RPE production of inflammation, as well as a potential role for damage by inflammation with chronicity if the inciting trigger is not neutralized, will be debated.
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24
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Estrago-Franco MF, Moustafa MT, Riazi-Esfahani M, Sapkal AU, Piche-Lopez R, Patil AJ, Sharma A, Falatoonzadeh P, Chwa M, Luczy-Bachman G, Kuppermann BD, Kenney MC. Effects of Benzo(e)pyrene on Reactive Oxygen/Nitrogen Species and Inflammatory Cytokines Induction in Human RPE Cells and Attenuation by Mitochondrial-involved Mechanism. J Ophthalmic Vis Res 2016; 11:385-393. [PMID: 27994808 PMCID: PMC5139551 DOI: 10.4103/2008-322x.194091] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Purpose: To identify inhibitors that could effectively lower reactive oxygen/nitrogen species (ROS/RNS), complement and inflammatory cytokine levels induced by Benzo(e)pyrene [B(e)p], an element of cigarette smoke, in human retinal pigment epithelial cells (ARPE-19) in vitro. Methods: ARPE-19 cells were treated for 24 hours with 200 μM, 100 μM, and 50 μM B(e)p or DMSO (dimethyl sulfoxide)-equivalent concentrations. Some cultures were pre-treated with ROS/RNS inhibitors (NG nitro-L-arginine, inhibits nitric oxide synthase; Apocynin, inhibits NADPH oxidase; Rotenone, inhibits mitochondrial complex I; Antimycin A, inhibits mitochondria complex III) and ROS/RNS levels were measured with a fluorescent H2 DCFDA assay. Multiplex bead arrays were used to measure levels of Interleukin-6 (IL-6), Interleukin-8 (IL-8), Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF), Transforming Growth Factor alpha (TGF-α) and Vascular Endothelial Growth Factor (VEGF). IL-6 levels were also measured by an enzyme-linked immunosorbent assay. Real-time qPCR analyses were performed with primers for C3 (component 3), CFH (inhibits complement activation), CD59 (inhibitor of the complement membrane attack complex (MAC)) and CD55/DAF (accelerates decay of target complement target proteins). Results: The ARPE-19 cultures treated with B(e)p showed significantly increased ROS/RNS levels (P < 0.001), which were then partially reversed by 6 μM Antimycin A (19%, P = 0.03), but not affected by the other ROS/RNS inhibitors. The B(e)p treated cultures demonstrated increased levels of IL-6 (33%; P = 0.016) and GM-CSF (29%; P = 0.0001) compared to DMSO-equivalent controls, while the expression levels for components of the complement pathway (C3, CFH, CD59 and CD55/DAF) were not changed. Conclusion: The cytotoxic effects of B(e)p include elevated ROS/RNS levels along with pro-inflammatory IL-6 and GM-CSF proteins. Blocking the Qi site of cytochrome c reductase (complex III) with Antimycin A led to partial reduction in B(e)p induced ROS production. Our findings suggest that inhibitors for multiple pathways would be necessary to protect the retinal cells from B(e)p induced toxicity.
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Affiliation(s)
- M Fernanda Estrago-Franco
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA, USA; Clinica Dres Estrago, Corrientes, Argentina
| | - M Tarek Moustafa
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA, USA; Ophthalmology Department, Minia University, Egypt
| | - Mohammad Riazi-Esfahani
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA, USA; Eye Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Ashish U Sapkal
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA, USA
| | - Rhina Piche-Lopez
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA, USA
| | - A Jayaprakash Patil
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA, USA; Royal Lancaster Infirmary, University Hospitals of Morecambe Bay NHS Trust, Lancaster, UK
| | - Ashish Sharma
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA, USA; Lotus Eye Care Hospital, Coimbatore, Tamil Nadu, India
| | - Payam Falatoonzadeh
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA, USA
| | - Marilyn Chwa
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA, USA
| | | | - Baruch D Kuppermann
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA, USA
| | - M Cristina Kenney
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA, USA
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25
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Taskintuna I, Elsayed MEAA, Schatz P. Update on Clinical Trials in Dry Age-related Macular Degeneration. Middle East Afr J Ophthalmol 2016; 23:13-26. [PMID: 26957835 PMCID: PMC4759891 DOI: 10.4103/0974-9233.173134] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
This review article summarizes the most recent clinical trials for dry age-related macular degeneration (AMD), the most common cause of vision loss in the elderly in developed countries. A literature search through websites https://www.pubmed.org and https://www.clinicaltrials.gov/, both accessed no later than November 04, 2015, was performed. We identified three Phase III clinical trials that were completed over the recent 5 years Age-Related Eye Disease Study 2 (AREDS2), implantable miniature telescope and tandospirone, and several other trials targeting a variety of mechanisms including, oxidative stress, complement inhibition, visual cycle inhibition, retinal and choroidal blood flow, stem cells, gene therapy, and visual rehabilitation. To date, none of the biologically oriented therapies have resulted in improved vision. Vision improvement was reported with an implantable mini telescope. Stem cells therapy holds a potential for vision improvement. The AREDS2 formulas did not add any further reduced risk of progression to advanced AMD, compared to the original AREDS formula. Several recently discovered pathogenetic mechanisms in dry AMD have enabled development of new treatment strategies, and several of these have been tested in recent clinical trials and are currently being tested in ongoing trials. The rapid development and understanding of pathogenesis holds promise for the future.
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Affiliation(s)
- Ibrahim Taskintuna
- Division of Vitreoretinal, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | | | - Patrik Schatz
- Division of Vitreoretinal, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia; Department of Ophthalmology, Clinical Sciences, Scane County University Hospital, University of Lund, Sweden
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The mTOR Kinase Inhibitor INK128 Blunts Migration of Cultured Retinal Pigment Epithelial Cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 854:709-15. [PMID: 26427479 DOI: 10.1007/978-3-319-17121-0_94] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Retinal pigment epithelium (RPE) cell migration in response to disease has been reported for age-related macular degeneration, proliferative vitreoretinopathy, and proliferative diabetic retinopathy. The complex molecular process of RPE cell migration is regulated in part by growth factors and cytokines, and activation of the PI3/AKT/mTOR signaling pathway. Rapamycin, an allosteric mTOR inhibitor, has been shown to block only one of the primary downstream mTOR effectors, p70 S6 kinase 1, in many cell types. INK128, a selective mTOR ATP binding site competitor, blocks both p70 S6 kinase 1 and a second primary downstream effector, 4E-BP1. We performed scratch assays using differentiated ARPE-19 and primary porcine RPE cells to assess the effect of mTOR inhibition on cell migration. We found that INK128-mediated blocking of both p70 S6 kinase 1 and 4E-BP1 was much more effective at preventing RPE cell migration than rapamycin-mediated inhibition of p70 S6 kinase 1 alone.
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Zhuang Y, Lyga J. Inflammaging in skin and other tissues - the roles of complement system and macrophage. ACTA ACUST UNITED AC 2015; 13:153-61. [PMID: 24853681 PMCID: PMC4082166 DOI: 10.2174/1871528113666140522112003] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 05/07/2014] [Accepted: 05/20/2014] [Indexed: 12/13/2022]
Abstract
Inflammaging refers to a continuous, low-grade inflammation associated with aging. Such chronic inflammatory response could build up with time and gradually causes tissue damage. It is considered as one of the driving forces for many age-related diseases such as diabetes, atherosclerosis, age-related macular degeneration (AMD), and skin aging. There is mounting evidence that indicates aging is driven by the pro-inflammatory cytokines and substances produced by our body’s innate immune system. The macrophage and complement system, two important components of innate immune system, have attracted more and more attention since they appear to be involved in the pathogenesis of several inflammaging-associated diseases, such as AMD and atherosclerosis. This paper will review what we know about these two innate immune systems in the pathogenesis of AMD, atherosclerosis and skin aging.
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Affiliation(s)
| | - John Lyga
- Avon Global R&D, 1 Avon Place, Suffern, NY, 10901, USA.
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Smit-McBride Z, Oltjen SL, Radu RA, Estep J, Nguyen AT, Gong Q, Hjelmeland LM. Localization of complement factor H gene expression and protein distribution in the mouse outer retina. Mol Vis 2015; 21:110-23. [PMID: 25684976 PMCID: PMC4323684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 02/03/2015] [Indexed: 11/28/2022] Open
Abstract
PURPOSE To determine the localization of complement factor H (Cfh) mRNA and its protein in the mouse outer retina. METHODS Quantitative real-time PCR (qPCR) was used to determine the expression of Cfh and Cfh-related (Cfhr) transcripts in the RPE/choroid. In situ hybridization (ISH) was performed using the novel RNAscope 2.0 FFPE assay to localize the expression of Cfh mRNA in the mouse outer retina. Immunohistochemistry (IHC) was used to localize Cfh protein expression, and western blots were used to characterize CFH antibodies used for IHC. RESULTS Cfh and Cfhr2 transcripts were detected in the mouse RPE/choroid using qPCR, while Cfhr1, Cfhr3, and Cfhrc (Gm4788) were not detected. ISH showed abundant Cfh mRNA in the RPE of all mouse strains (C57BL/6, BALB/c, 129/Sv) tested, with the exception of the Cfh(-/-) eye. Surprisingly, the Cfh protein was detected by immunohistochemistry in photoreceptors rather than in RPE cells. The specificity of the CFH antibodies was tested by western blotting. Our CFH antibodies recognized purified mouse Cfh protein, serum Cfh protein in wild-type C57BL/6, BALB/c, and 129/Sv, and showed an absence of the Cfh protein in the serum of Cfh(-/-) mice. Greatly reduced Cfh protein immunohistological signals in the Cfh(-/-) eyes also supported the specificity of the Cfh protein distribution results. CONCLUSIONS Only Cfh and Cfhr2 genes are expressed in the mouse outer retina. Only Cfh mRNA was detected in the RPE, but no protein. We hypothesize that the steady-state concentration of Cfh protein is low in the cells due to secretion, and therefore is below the detection level for IHC.
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Affiliation(s)
| | - Sharon L. Oltjen
- Department of Ophthalmology, University of California, Davis, CA
| | - Roxana A. Radu
- Jules Stein Eye Institute, University of California, Los Angeles, CA
| | - Jason Estep
- Department of Human Anatomy and Cell Biology, University of California, Davis, CA
| | | | - Qizhi Gong
- Department of Human Anatomy and Cell Biology, University of California, Davis, CA
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Schnabolk G, Coughlin B, Joseph K, Kunchithapautham K, Bandyopadhyay M, O'Quinn EC, Nowling T, Rohrer B. Local production of the alternative pathway component factor B is sufficient to promote laser-induced choroidal neovascularization. Invest Ophthalmol Vis Sci 2015; 56:1850-63. [PMID: 25593023 DOI: 10.1167/iovs.14-15910] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
PURPOSE Complement factor B (CFB) is a required component of the alternative pathway (AP) of complement, and CFB polymorphisms are associated with age-related macular degeneration (AMD) risk. Complement factor B is made in the liver, but expression has also been detected in retina and retinal pigment epithelium (RPE)-choroid. We investigated whether production of CFB by the RPE can promote AP activation in mouse choroidal neovascularization (CNV). METHODS Transgenic mice expressing CFB under the RPE65 promoter were generated and crossed onto factor B-deficient (CFB-KO) mice. Biological activity was determined in vitro using RPE monolayers and in vivo using laser-induced CNV. Contribution of systemic CFB was investigated using CFB-KO reconstituted with CFB-sufficient serum. RESULTS Transgenic mice (CFB-tg) expressed CFB in RPE-choroid; no CFB was detected in serum. Cultured CFB-tg RPE monolayers secreted CFB apically and basally upon exposure to oxidative stress that was biologically active. Choroidal neovascularization sizes were comparable between wild-type and CFB-tg mice, but significantly increased when compared to lesions in CFB-KO mice. Injections of CFB-sufficient serum into CFB-KO mice resulted in partial reconstitution of systemic AP activity and significantly increased CNV size. CONCLUSIONS Mouse RPE cells express and secrete CFB sufficient to promote RPE damage and CNV. This further supports that local complement production may regulate disease processes; however, the reconstitution experiments suggest that additional components may be sequestered from the bloodstream. Understanding the process of ocular complement production and regulation will further our understanding of the AMD disease process and the requirements of a complement-based therapeutic.
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Affiliation(s)
- Gloriane Schnabolk
- Research Service, Ralph H. Johnson VA Medical Center, Charleston, South Carolina, United States
| | - Beth Coughlin
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Kusumam Joseph
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Kannan Kunchithapautham
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Mausumi Bandyopadhyay
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Elizabeth C O'Quinn
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Tamara Nowling
- Department of Medicine, Division of Rheumatology and Immunology, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Bärbel Rohrer
- Research Service, Ralph H. Johnson VA Medical Center, Charleston, South Carolina, United States Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, United States
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Activation of endogenously expressed ion channels by active complement in the retinal pigment epithelium. Pflugers Arch 2014; 467:2179-91. [PMID: 25427445 DOI: 10.1007/s00424-014-1656-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 11/07/2014] [Accepted: 11/13/2014] [Indexed: 10/24/2022]
Abstract
Defective regulation of the alternative pathway of the complement system is believed to contribute to damage of retinal pigment epithelial (RPE) cells in age-related macular degeneration. Thus we investigated the effect of complement activation on the RPE cell membrane by analyzing changes in membrane conductance via patch-clamp techniques and Ca(2+) imaging. Exposure of human ARPE-19 cells to complement-sufficient normal human serum (NHS) (25 %) resulted in a biphasic increase in intracellular free Ca(2+) ([Ca(2+)]i); an initial peak followed by sustained Ca(2+) increase. C5- or C7-depleted sera did not fully reproduce the signal generated by NHS. The initial peak of the Ca(2+) response was reduced by sarcoplasmic Ca(2+)-ATPase inhibitor thapsigargin, L-type channel blockers (R)-(+)-BayK8644 and isradipine, transient-receptor-potential (TRP) channel blocker ruthenium-red and ryanodine receptor blocker dantrolene. The sustained phase was carried by CaV1.3 L-type channels via tyrosine-phosphorylation. Changes in [Ca(2+)]I were accompanied by an abrupt hyperpolarization, resulting from a transient increase in membrane conductance, which was absent under extracellular Ca(2+)- or K(+)-free conditions and blocked by (R)-(+)-BayK8644 or paxilline, a maxiK channel inhibitor. Single-channel recordings confirmed the contribution of maxiK channels. Primary porcine RPE cells responded to NHS in a comparable manner. Pre-incubation with NHS reduced H2O2-induced cell death. In summary, in a concerted manner, C3a, C5a and sC5b-9 increased [Ca(2+)]i by ryanodine-receptor-dependent activation of L-type channels in addition to maxi-K channels and TRP channels absent from any insertion of a lytic pore.
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Kawa MP, Machalinska A, Roginska D, Machalinski B. Complement system in pathogenesis of AMD: dual player in degeneration and protection of retinal tissue. J Immunol Res 2014; 2014:483960. [PMID: 25276841 PMCID: PMC4168147 DOI: 10.1155/2014/483960] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 07/18/2014] [Accepted: 08/01/2014] [Indexed: 12/25/2022] Open
Abstract
Age-related macular degeneration (AMD) is the most common cause of blindness among the elderly, especially in Western countries. Although the prevalence, risk factors, and clinical course of the disease are well described, its pathogenesis is not entirely elucidated. AMD is associated with a variety of biochemical abnormalities, including complement components deposition in the retinal pigment epithelium-Bruch's membrane-choriocapillaris complex. Although the complement system (CS) is increasingly recognized as mediating important roles in retinal biology, its particular role in AMD pathogenesis has not been precisely defined. Unrestricted activation of the CS following injury may directly damage retinal tissue and recruit immune cells to the vicinity of active complement cascades, therefore detrimentally causing bystander damage to surrounding cells and tissues. On the other hand, recent evidence supports the notion that an active complement pathway is a necessity for the normal maintenance of the neurosensory retina. In this scenario, complement activation appears to have beneficial effect as it promotes cell survival and tissue remodeling by facilitating the rapid removal of dying cells and resulting cellular debris, thus demonstrating anti-inflammatory and neuroprotective activities. In this review, we discuss both the beneficial and detrimental roles of CS in degenerative retina, focusing on the diverse aspects of CS functions that may promote or inhibit macular disease.
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Affiliation(s)
- Milosz P. Kawa
- Department of General Pathology, Pomeranian Medical University, Al. Powstancow Wlkp. 72, 70-111 Szczecin, Poland
| | - Anna Machalinska
- Department of Ophthalmology, Pomeranian Medical University, Al. Powstancow Wlkp. 72, 70-111 Szczecin, Poland
- Department of Histology and Embryology, Pomeranian Medical University, Al. Powstancow Wlkp. 72, 70-111 Szczecin, Poland
| | - Dorota Roginska
- Department of General Pathology, Pomeranian Medical University, Al. Powstancow Wlkp. 72, 70-111 Szczecin, Poland
| | - Boguslaw Machalinski
- Department of General Pathology, Pomeranian Medical University, Al. Powstancow Wlkp. 72, 70-111 Szczecin, Poland
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Abstract
IMPORTANCE Geographic atrophy (GA) is the major cause of blind registration in Western communities, although, with few exceptions, it is less common than choroidal neovascular disease. The variation of phenotype implies that age-related macular degeneration (AMD) does not follow the same course from one case to another and that phenotyping may be important before initiating a therapeutic trial. OBJECTIVE To document photoreceptor and retinal pigment epithelium (RPE) cell loss and other changes at the RPE-choroid interface in donated human eyes in which visual loss was deemed to be due to GA. DESIGN, SETTING, AND PARTICIPANTS Histological study of a consecutive series of eyes donated by individuals previously diagnosed clinically as having GA. Donors were chosen on the basis of available clinical records (from MidAmerica Transplant Services, St Louis, Missouri; the Iowa Lions Eye Bank, Iowa City; and the Utah Lions Eye Bank, Salt Lake City) and selected were those considered to have GA due to AMD. Tissues in the regions of atrophy were examined with light, electron, and autofluorescence microscopy. RESULTS In most of the 37 donors examined, there was marked loss of photoreceptor cells for variable distances distal from the edge of the GA. Rod loss was greater than cone loss. An inverse relationship existed between the quantity of autofluorescent inclusions in the RPE and the thickness of sub-RPE basal laminar deposit. Integrity of the choroid varied from one eye to another and was not related strictly to photoreceptor survival. In some eyes, photoreceptor loss existed in the absence of obvious morphological changes in the Bruch membrane or RPE. CONCLUSIONS AND RELEVANCE The findings support the view that photoreceptor loss occurs early in AMD in a proportion of cases and imply that photoreceptor-cell loss may contribute to the functional loss recorded in early stages of AMD at least in part. The variation of changes from one eye to another implies that patients selected for a specific prophylactic therapy for early AMD should be chosen on the basis of the characteristics of their disease.
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Affiliation(s)
- Alan C Bird
- Institute of Ophthalmology, University College London, London, England
| | | | - Gregory S Hageman
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, Moran Center for Translational Medicine, University of Utah, Salt Lake City
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Weinberger AWA, Eddahabi C, Carstesen D, Zipfel PF, Walter P, Skerka C. Human complement factor H and factor H-like protein 1 are expressed in human retinal pigment epithelial cells. Ophthalmic Res 2013; 51:59-66. [PMID: 24280833 DOI: 10.1159/000351624] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Accepted: 04/14/2013] [Indexed: 11/19/2022]
Abstract
BACKGROUND A common haplotype in the gene for the regulator of the alternative pathway of complement activation factor H has been linked to individual predisposition to age- related macular degeneration (AMD). METHODS In this study, retinal pigment epithelial (RPE) cells, i.e. immortalized ARPE-19 as well as primary human RPE cells, were investigated for expression of factor H and FHL-1 by immunohistochemistry and in situ hybridization analysis. RESULTS Factor H and the alternative spliced product FHL-1 are expressed in RPE cells, i.e. in immortalized ARPE-19 and primary human RPE cells. Factor H and FHL-1 expression was induced in a dose-dependent manner in ARPE-19 cells upon treatment with the inflammatory marker interleukin-6 (IL-6). In situ hybridization experiments confirmed an elevated expression rate of the factor H gene in IL-6-treated ARPE-19 cells. AMD is characterized by complement-associated inflammatory processes in the retina. Thus, local synthesis of complement regulators affects the protection of retinal cells and may be involved in the pathogenesis at the RPE-choroid interface.
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Ardeljan D, Chan CC. Aging is not a disease: distinguishing age-related macular degeneration from aging. Prog Retin Eye Res 2013; 37:68-89. [PMID: 23933169 PMCID: PMC3830684 DOI: 10.1016/j.preteyeres.2013.07.003] [Citation(s) in RCA: 168] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 07/29/2013] [Accepted: 07/30/2013] [Indexed: 12/18/2022]
Abstract
Age-related macular degeneration (AMD) is a disease of the outer retina, characterized most significantly by atrophy of photoreceptors and retinal pigment epithelium accompanied with or without choroidal neovascularization. Development of AMD has been recognized as contingent on environmental and genetic risk factors, the strongest being advanced age. In this review, we highlight pathogenic changes that destabilize ocular homeostasis and promote AMD development. With normal aging, photoreceptors are steadily lost, Bruch's membrane thickens, the choroid thins, and hard drusen may form in the periphery. In AMD, many of these changes are exacerbated in addition to the development of disease-specific factors such as soft macular drusen. Para-inflammation, which can be thought of as an intermediate between basal and robust levels of inflammation, develops within the retina in an attempt to maintain ocular homeostasis, reflected by increased expression of the anti-inflammatory cytokine IL-10 coupled with shifts in macrophage plasticity from the pro-inflammatory M1 to the anti-inflammatory M2 polarization. In AMD, imbalances in the M1 and M2 populations together with activation of retinal microglia are observed and potentially contribute to tissue degeneration. Nonetheless, the retina persists in a state of chronic inflammation and increased expression of certain cytokines and inflammasomes is observed. Since not everyone develops AMD, the vital question to ask is how the body establishes a balance between normal age-related changes and the pathological phenotypes in AMD.
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Affiliation(s)
- Daniel Ardeljan
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA; Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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Yang MM, Lai TYY, Tam POS, Chiang SWY, Ng TK, Rong SS, Pang CP. Association of CFH and SERPING1 polymorphisms with anterior uveitis. Br J Ophthalmol 2013; 97:1475-80. [PMID: 23966370 DOI: 10.1136/bjophthalmol-2013-303679] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIMS To investigate the association of the complement factor H (CFH) and complement component 1 inhibitor (SERPING1) genes with anterior uveitis (AU). METHODS A total of 406 subjects (98 patients with AU and 308 controls) were recruited for this study. Two CFH polymorphisms (rs3753394 and rs1065489) and two SERPING1 polymorphisms (rs1005511 and rs3824988) were genotyped using TaqMan genotyping assays. Analyses were stratified for gender and human leukocyte antigen (HLA)-B27 status. Correlations of the genotypes with multiple clinical features were also evaluated. RESULTS No significant association was found between any of the four polymorphisms and AU after multiple testing corrections. However, stratified analyses showed that there were significant increases in the frequencies of T allele and TT homozygosity for CFH-rs1065489 in female patients compared with that of controls (pcorr=0.004 and pcorr=0.012 respectively). In addition, CFH-rs1065489 was also associated with AU in patients who were HLA-B27 positive. No significant association with AU was found for the other three single nucleotide polymorphisms (SNPs), even stratified by gender or HLA-B27 status. Genotype-phenotype analyses found that CFH-rs1065489 TT genotype was associated with higher uveitis recurrence frequency. No correlation was found between CFH-rs1065489 and other clinical features. CONCLUSIONS This study revealed an association of CFH-rs1065489 with AU as well as uveitis recurrence frequency. The influence on AU could be gender specific and dependent on HLA-B27 status. Our results also suggested that SERPING1 does not play a significant role in the development of AU.
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Affiliation(s)
- Ming-ming Yang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, , Hong Kong, China
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Williams JAE, Greenwood J, Moss SE. Retinal changes precede visual dysfunction in the complement factor H knockout mouse. PLoS One 2013; 8:e68616. [PMID: 23844226 PMCID: PMC3699560 DOI: 10.1371/journal.pone.0068616] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 05/31/2013] [Indexed: 12/21/2022] Open
Abstract
We previously reported that aged mice lacking complement factor H (CFH) exhibit visual defects and structural changes in the retina. However, it is not known whether this phenotype is age-related or is the consequence of disturbed development. To address this question we investigated the effect of Cfh gene deletion on the retinal phenotype of young and mid-age mice. Cfh(-/-) mouse eyes exhibited thickening of the retina and reduced nuclear density, but relatively normal scotopic and photopic electroretinograms. At 12 months there was evidence of subtle astroglial activation in the Cfh(-/-) eyes, and significant elevation of the complement regulator, decay-accelerating factor (DAF) in Müller cells. In the retinal pigment epithelium (RPE) of young control and Cfh(-/-) animals mitochondria and melanosomes were oriented basally and apically respectively, whereas the apical positioning of melanosomes was significantly perturbed in the mid-age Cfh(-/-) RPE. We conclude that deletion of Cfh in the mouse leads to defects in the retina that precede any marked loss of visual function, but which become progressively more marked as the animals age. These observations are consistent with a lifelong role for CFH in retinal homeostasis.
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Affiliation(s)
| | - John Greenwood
- Department of Cell Biology, UCL Institute of Ophthalmology, London, United Kingdom
| | - Stephen E. Moss
- Department of Cell Biology, UCL Institute of Ophthalmology, London, United Kingdom
- * E-mail:
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Thompson IA, Liu B, Sen HN, Jiao X, Katamay R, Li Z, Hu M, Hejtmancik F, Nussenblatt RB. Association of complement factor H tyrosine 402 histidine genotype with posterior involvement in sarcoid-related uveitis. Am J Ophthalmol 2013; 155:1068-1074.e1. [PMID: 23497844 DOI: 10.1016/j.ajo.2013.01.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Revised: 01/12/2013] [Accepted: 01/16/2013] [Indexed: 10/27/2022]
Abstract
PURPOSE To determine whether the complement factor H (CFH) tyrosine 402 histidine (Y402H) variant, recently shown to be associated with age-related macular degeneration (AMD) and multifocal choroiditis, is associated with specific ocular sarcoidosis clinical phenotypes in black and white persons. DESIGN Case-control study. METHODS The CFH Y402H polymorphism (rs1061170) was genotyped in 41 subjects with ocular sarcoidosis and 393 control subjects. Allele frequencies in the ocular sarcoidosis cases were compared with controls using chi-square score tests. Genotypic model-based (dominant, recessive, and additive) associations of the rs1061170 allele were tested using multivariate logistic regression. Bayesian information criteria were used to formalize model selection. Genotypes were correlated with disease characteristics and severity of ocular inflammation. RESULTS The C allele (rs1061170) was found in 35% of controls, but occurred with a significantly higher frequency (48.7%) in ocular sarcoidosis cases (odds ratio, 1.72; 95% confidence interval, 1.09 to 2.78; P = .018). Logistic regression demonstrated an association between rs1061170 and ocular sarcoidosis in 2 of 3 genetic models (additive, P = .0078; recessive, P = .0018). Posterior uveitis and panuveitis were overrepresented significantly in cases with the homozygous variant genotype (CC, 91%; P = .047). The population-attributable risk related to this CFH risk variant was 20%. CONCLUSIONS The Y402H polymorphism of CFH seems to be associated with ocular sarcoidosis in black and white persons. Carriage of the CFH Y402H polymorphism in both alleles is associated with an increased risk for posterior uveitis and panuveitis presentation. The prognostic importance of this genotype will require prolonged follow-up studies.
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Kay P, Yang YC, Paraoan L. Directional protein secretion by the retinal pigment epithelium: roles in retinal health and the development of age-related macular degeneration. J Cell Mol Med 2013; 17:833-43. [PMID: 23663427 PMCID: PMC3822888 DOI: 10.1111/jcmm.12070] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 03/24/2013] [Indexed: 11/29/2022] Open
Abstract
The structural and functional integrity of the retinal pigment epithelium (RPE) is fundamental for maintaining the function of the neuroretina. These specialized cells form a polarized monolayer that acts as the retinal–blood barrier, separating two distinct environments with highly specialized functions: photoreceptors of the neuroretina at the apical side and Bruch's membrane/highly vascularized choriocapillaris at the basal side. The polarized nature of the RPE is essential for the health of these two regions, not only in nutrient and waste transport but also in the synthesis and directional secretion of proteins required in maintaining retinal homoeostasis and function. Although multiple malfunctions within the RPE cells have been associated with development of age-related macular degeneration (AMD), the leading cause of legal blindness, clear causative processes have not yet been conclusively characterized at the molecular and cellular level. This article focuses on the involvement of directionally secreted RPE proteins in normal functioning of the retina and on the potential association of incorrect RPE protein secretion with development of AMD. Understanding the importance of RPE polarity and the correct secretion of essential structural and regulatory components emerge as critical factors for the development of novel therapeutic strategies targeting AMD.
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Affiliation(s)
- Paul Kay
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
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Parainflammation associated with advanced glycation endproduct stimulation of RPE in vitro: implications for age-related degenerative diseases of the eye. Cytokine 2013; 62:369-81. [PMID: 23601964 DOI: 10.1016/j.cyto.2013.03.027] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 03/14/2013] [Accepted: 03/26/2013] [Indexed: 12/22/2022]
Abstract
Age related macular degeneration (AMD) is one of the leading causes of blindness in Western society. A hallmark of early stage AMD are drusen, extracellular deposits that accumulate in the outer retina. Advanced glycation endproducts (AGE) accumulate with aging and are linked to several age-related diseases such as Alzheimer's disease, osteoarthritis, atherosclerosis and AMD. AGE deposits are found in drusen and in Bruch's membrane of the eye and several studies have suggested its role in promoting oxidative stress, apoptosis and lipofuscin accumulation. Recently, complement activation and chronic inflammation have been implicated in the pathogenesis of AMD. While AGEs have been shown to promote inflammation in other diseases, whether it plays a similar role in AMD is not known. This study investigates the effects of AGE stimulation on pro- and anti-inflammatory pathways in primary culture of human retinal pigment epithelial cells (RPE). Differential gene expression studies revealed a total of 41 up- and 18 down-regulated RPE genes in response to AGE stimulation. These genes fell into three categories as assessed by gene set enrichment analysis (GSEA). The main categories were inflammation (interferon-induced, immune response) and proteasome degradation, followed by caspase signaling. Using suspension array technology, protein levels of secreted cytokines and growth factors were also examined. Anti-inflammatory cytokines including IL10, IL1ra and IL9 were all overexpressed. Pro-inflammatory cytokines including IL4, IL15 and IFN-γ were overexpressed, while other pro-inflammatory cytokines including IL8, MCP1, IP10 were underexpressed after AGE stimulation, suggesting a para-inflammation state of the RPE under these conditions. Levels of mRNA of chemokine, CXCL11, and viperin, RSAD2, were up-regulated and may play a role in driving the inflammatory response via the NF-kB and JAK-STAT pathways. CXCL11 was strongly immunoreactive and associated with drusen in the AMD eye. The pathways and novel genes identified here highlight inflammation as a key response to AGE stimulation in primary culture of human RPE, and identify chemokine CXCL11 as putative novel agent associated with the pathogenesis of AMD.
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Bird AC. Pathogenetic Mechanisms in Age-Related Macular Degeneration. Retina 2013. [DOI: 10.1016/b978-1-4557-0737-9.00064-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Yuda K, Takahashi H, Inoue T, Ueta T, Iriyama A, Kadonosono K, Tamaki Y, Aburatani H, Nagai R, Yanagi Y. Adrenomedullin Inhibits Choroidal Neovascularization via CCL2 in the Retinal Pigment Epithelium. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 181:1464-72. [DOI: 10.1016/j.ajpath.2012.06.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 05/01/2012] [Accepted: 06/28/2012] [Indexed: 12/15/2022]
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Complement factor H and interleukin gene polymorphisms in patients with non-infectious intermediate and posterior uveitis. Mol Vis 2012; 18:1865-72. [PMID: 22876110 PMCID: PMC3413425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 07/07/2012] [Indexed: 11/26/2022] Open
Abstract
OBJECTIVE To investigate the associations of complement factor H (CFH), KIAA1109, and interleukin-27 (IL-27) gene polymorphisms in patients with non-infectious intermediate and posterior uveitis. METHODS The study cohort consisted of a total of 95 Chinese non-infectious uveitis patients, including 38 patients with intermediate uveitis (IU), 38 patients with Vogt-Koyanagi-Harada disease (VKH), and 19 patients with Behçet's disease and 308 healthy controls. The genotypes of CFH-rs800292, KIAA1109-rs4505848, and IL27-rs4788084 were determined using TaqMan single nucleotide polymorphism genotyping assays. RESULTS The frequency of carriers of G allele for CFH-rs800292 was significantly higher in patients with non-infectious intermediate and posterior uveitis than in controls (GG/AG versus AA; p=0.02). No significant association was found between uveitis and both KIAA1109-rs4505848 and IL27-rs4788084. In stratified analysis by gender, the frequency of carriers with G allele for KIAA1109-rs4505848 was significantly higher in male uveitis patients than in male controls (GG/AG versus AA; p=0.034). There was no significant difference in allelic and genotypic frequencies for CFH-rs800292 and IL27-rs4788084 in either male or female groups. In addition, higher frequency of KIAA1109-rs4505848 G allele was found in Behçet's disease patients compared with controls and IU patients (p=0.01 and p=0.003, respectively). CONCLUSIONS Our results demonstrated that CFH-rs800292 and KIAA1109-rs4505848 are associated with non-infectious intermediate and posterior uveitis. Moreover, gender susceptibility for uveitis might be involved in the KIAA1109 gene and the KIAA1109-rs4505848 polymorphism might be associated with the development of Behçet's disease.
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Sparrow JR, Ueda K, Zhou J. WITHDRAWN: Complement dysregulation in AMD: RPE-Bruch's membrane-choroid. Mol Aspects Med 2012:S0098-2997(12)00040-4. [PMID: 22542573 DOI: 10.1016/j.mam.2012.03.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 03/30/2012] [Indexed: 12/01/2022]
Abstract
The Publisher regrets that this article is an accidental duplication of an article that has already been published, doi:10.1016/j.mam.2012.03.011. The duplicate article has therefore been withdrawn.
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Affiliation(s)
- Janet R Sparrow
- Department of Ophthalmology, Columbia University, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
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Bandyopadhyay M, Rohrer B. Matrix metalloproteinase activity creates pro-angiogenic environment in primary human retinal pigment epithelial cells exposed to complement. Invest Ophthalmol Vis Sci 2012; 53:1953-61. [PMID: 22408008 DOI: 10.1167/iovs.11-8638] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
PURPOSE Mechanistic studies have shown that inflammation, complement activation, extracellular matrix (ECM) turnover, growth factor imbalance, and oxidative stress are fundamental components of age-related macular degeneration (AMD). Matrix metalloproteinases (MMPs) mediate ECM turnover but also process various bioactive molecules. Here, we tested whether complement attack on RPE monolayers changes MMP secretion and activation, thereby altering the availability of growth factors in the extracellular space. METHODS Human embryonic RPE monolayers with stable transepithelial resistance (TER) were established. Complement activation was induced with H₂O₂ and normal human serum. MMP-2/9, vascular endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF) protein, and mRNA levels were analyzed by Western blotting, ELISA, and real-time PCR; activity of MMP-2/9 by gelatin zymography. RESULTS Complement activation resulted in a loss of TER, which required transient membrane attack complex formation, activation of the alternative pathway, and VEGF secretion and signaling. Despite the generation of reactive oxygen species, cellular integrity or intracellular adenosine triphosphate (ATP) levels were unaffected. However, expression of MMP-2/9 and their protease activity was elevated. Inhibition of MMP-2/9 activity increased PEDF and decreased VEGF levels in the apical and basal supernatants but had no effect on their expression levels. VEGF levels in the supernatant correlated with the level TER reduction. CONCLUSIONS These studies suggest that complement activation, by altering the expression and activation of MMPs, has the ability to generate a proangiogenic environment by altering the balance between VEGF and PEDF. Our findings link reported results that have been associated with AMD pathogenesis; oxidative stress; complement activation; VEGF/PEDF ratio; and MMP activity.
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Affiliation(s)
- Mausumi Bandyopadhyay
- Department of Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA
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Sparrow JR, Ueda K, Zhou J. Complement dysregulation in AMD: RPE-Bruch's membrane-choroid. Mol Aspects Med 2012; 33:436-45. [PMID: 22504022 DOI: 10.1016/j.mam.2012.03.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 03/30/2012] [Indexed: 01/01/2023]
Abstract
The question as to why the macula of the retina is prone to an aging disease (age-related macular degeneration) remains unanswered. This unmet challenge has implications since AMD accounts for approximately 54% of blindness in the USA (Swaroop, Chew, Bowes Rickman and Abecasis, 2009). While AMD has onset in the elder years, it likely develops over time. Genetic discovery to date has accounted for approximately 50% of the inheritable component of AMD. The polymorphism that has been most widely studied is the Y402H allele in the complement factor H gene. The implication of this genetic association is that in a subset of AMD cases, unregulated complement activation is permissive for AMD. Given that this gene variant results in an amino acid substitution, it is assumed that this change will have functional consequences although the precise mechanisms are still unknown. Genetic predisposition is not the only factor however, since in this complex disease there is substantial evidence that lifestyle factors such as diet and smoking contribute to risk. Here we provide an overview of current knowledge with respect to factors involved in AMD pathogenesis. Interwoven with these issues is a discussion of the significant role played by aging processes, some of which are unique to the retina and retinal pigment epithelium. One recurring theme is the potential for disease promotion by diverse types of oxidation products.
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Affiliation(s)
- Janet R Sparrow
- Department of Ophthalmology, Columbia University, New York, NY 10032, USA.
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Yang MM, Lai TY, Tam PO, Chiang SW, Chan CK, Luk FO, Ng TK, Pang CP. CFH 184G as a genetic risk marker for anterior uveitis in Chinese females. Mol Vis 2011; 17:2655-64. [PMID: 22065918 PMCID: PMC3209418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 09/29/2011] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE To investigate the association of three single nucleotide polymorphisms (SNPs) in the complement factor H (CFH), KIAA1109, and interleukin-27 (IL-27) genes in patients with anterior uveitis (AU). METHODS A case-control study was performed in 98 Chinese AU patients and 308 healthy controls. Three SNPs including CFH-rs800292, KIAA1109-rs4505848, and IL27-rs4788084 were detected using TaqMan SNP Genotyping Assays. Analyses were also stratified according to gender, clinical features and human leukocyte antigen (HLA)-B27 status of the patients. RESULTS No significant association was found between all three SNPs and AU. However, when stratified by gender, there were significant increases in the frequency of the CFH-rs800292 184G allele and GG homozygosity in female patients compared with control subjects (p=0.003 and p=0.009, respectively). Similar association was not detected in males. No significant association was found between AU and KIAA1109-rs4505848 or IL27-rs4788084 even stratified by gender. There was no significant difference in genotypes of AU patients stratified by various clinical features. Subgroup analyses showed that all three SNPs (rs800292, rs4505848, and rs4788084) were not associated with AU in HLA-B27-positive patients, neither in HLA-B27-negative patients. CONCLUSIONS Our results showed an association between AU and CFH polymorphism in Chinese female patients but not in males, indicating gender-specific genetic differences in CFH. Gender should be considered in genetic studies of anterior uveitis even extending to other immunologic diseases.
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Cell culture model that mimics drusen formation and triggers complement activation associated with age-related macular degeneration. Proc Natl Acad Sci U S A 2011; 108:18277-82. [PMID: 21969589 DOI: 10.1073/pnas.1109703108] [Citation(s) in RCA: 152] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We introduce a human retinal pigmented epithelial (RPE) cell-culture model that mimics several key aspects of early stage age-related macular degeneration (AMD). These include accumulation of sub-RPE deposits that contain molecular constituents of human drusen, and activation of complement leading to formation of deposit-associated terminal complement complexes. Abundant sub-RPE deposits that are rich in apolipoprotein E (APOE), a prominent drusen constituent, are formed by RPE cells grown on porous supports. Exposure to human serum results in selective, deposit-associated accumulation of additional known drusen components, including vitronectin, clusterin, and serum amyloid P, thus suggesting that specific protein-protein interactions contribute to the accretion of plasma proteins during drusen formation. Serum exposure also leads to complement activation, as evidenced by the generation of C5b-9 immunoreactive terminal complement complexes in association with APOE-containing deposits. Ultrastructural analyses reveal two morphologically distinct forms of deposits: One consisting of membrane-bounded multivesicular material, and the other of nonmembrane-bounded particle conglomerates. Collectively, these results suggest that drusen formation involves the accumulation of sub-RPE material rich in APOE, a prominent biosynthetic product of the RPE, which interacts with a select group of drusen-associated plasma proteins. Activation of the complement cascade appears to be mediated via the classical pathway by the binding of C1q to ligands in APOE-rich deposits, triggering direct activation of complement by C1q, deposition of terminal complement complexes and inflammatory sequelae. This model system will facilitate the analysis of molecular and cellular aspects of AMD pathogenesis, and the testing of new therapeutic agents for its treatment.
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Cao GF, Liu Y, Yang W, Wan J, Yao J, Wan Y, Jiang Q. Rapamycin sensitive mTOR activation mediates nerve growth factor (NGF) induced cell migration and pro-survival effects against hydrogen peroxide in retinal pigment epithelial cells. Biochem Biophys Res Commun 2011; 414:499-505. [PMID: 21968016 DOI: 10.1016/j.bbrc.2011.09.094] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2011] [Accepted: 09/19/2011] [Indexed: 11/16/2022]
Abstract
Patients with age related macular degeneration (AMD) have a loss of vision in the center of the visual field. Oxidative stress plays an important role in this progress. Nerve growth factor (NGF) is important for the survival and maintenance of sympathetic and sensory neurons and NGF eye drops improve visual acuity and electro-functional activity in patients with AMD. However, the molecular mechanisms and signaling events involved in this have not been fully investigated. Using cultured human retinal pigment epithelial (RPE) cells, we demonstrate here that NGF protects RPE cells against hydrogen peroxide (H(2)O(2))-induced cell apoptosis. NGF also induces RPE cell migration, the latter is important for retinal regeneration and the recovery from AMD. H(2)O(2) decreases S6 phosphorylation and cell viability, which is restored by NGF. Rapamycin, the pharmacologic inhibitor of mammalian target of rapamycin (mTOR), diminished NGF-induced S6 phosphorylation, cell migration and protective effects against oxidative stress. Collectively, we conclude that activation of rapamycin sensitive mTOR signaling mediates NGF induced cell migration and pro-survival effects in H(2)O(2) treated RPE cells.
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Affiliation(s)
- Guo-Fan Cao
- The Affiliated Eye Hospital of Nanjing Medical University, Nanjing 210029, China
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Fraczek LA, Martin CB, Martin BK. c-Jun and c-Fos regulate the complement factor H promoter in murine astrocytes. Mol Immunol 2011; 49:201-10. [PMID: 21920606 DOI: 10.1016/j.molimm.2011.08.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 08/08/2011] [Accepted: 08/18/2011] [Indexed: 11/24/2022]
Abstract
The complement system is a critical component of innate immunity that requires regulation to avoid inappropriate activation. This regulation is provided by many proteins, including complement factor H (CFH), a critical regulator of the alternative pathway of complement activation. Given its regulatory function, mutations in CFH have been implicated in diseases such as age-related macular degeneration and membranoproliferative glomerulonephritis, and central nervous system diseases such as Alzheimer's disease, Parkinson's disease, and a demyelinating murine model, experimental autoimmune encephalomyelitis (EAE). There have been few investigations on the transcriptional regulation of CFH in the brain and CNS. Our studies show that CFH mRNA is present in several CNS cell types. The murine CFH (mCFH) promoter was cloned and examined through truncation constructs and we show that specific regions throughout the promoter contain enhancers and repressors that are positively regulated by inflammatory cytokines in astrocytes. Database mining of these regions indicated transcription factor binding sites conserved between different species, which led to the investigation of specific transcription factor binding interactions in a 241 base pair (bp) region at -416 bp to -175 bp that showed the strongest activity. Through supershift analysis, it was determined that c-Jun and c-Fos interact with the CFH promoter in astrocytes in this region. These results suggest a relationship between cell cycle and complement regulation, and how these transcription factors and CFH affect disease will be a valuable area of investigation.
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Affiliation(s)
- Laura A Fraczek
- Interdisciplinary Program in Immunology, University of Iowa, Iowa City, IA 52242, United States
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Khandhadia S, Cipriani V, Yates JRW, Lotery AJ. Age-related macular degeneration and the complement system. Immunobiology 2011; 217:127-46. [PMID: 21868123 DOI: 10.1016/j.imbio.2011.07.019] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2011] [Revised: 06/22/2011] [Accepted: 07/18/2011] [Indexed: 11/30/2022]
Abstract
Age-related macular degeneration (AMD) is the leading cause of blindness in the developed world. It is a complex multifactorial disease, and despite new advances in treatment, many patients still succumb to visual impairment. The complement pathway has been implicated in the pathogenesis of many diseases, and recently variants in several genes encoding complement pathway proteins have been associated with AMD. Complement proteins have been found in histological specimens of eyes with AMD. Altered levels of both intrinsic complement proteins and activated products have been found in the circulation of patients with AMD. Complement activation may be triggered by oxidative stress, resulting from retinal exposure to incoming light; indeed an inter-play between these two pathological processes seems to exist. Finally, complement inhibitors are currently being evaluated in clinical trials. This article reviews the role of the complement system in AMD, and the potential of complement inhibition in preventing the devastating blindness resulting from this disease.
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Affiliation(s)
- S Khandhadia
- Clinical Neurosciences Division, University of Southampton, UK
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