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Tsoi SM, Steurer M, Maltepe E, Fineman JR. Pre-eclampsia and barker's hypothesis: are we beginning to see the trees within the forest? Pediatr Res 2024:10.1038/s41390-024-03264-7. [PMID: 38822134 DOI: 10.1038/s41390-024-03264-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Accepted: 04/29/2024] [Indexed: 06/02/2024]
Affiliation(s)
- Stephanie M Tsoi
- Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA
| | - Martina Steurer
- Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA
| | - Emin Maltepe
- Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA
| | - Jeffrey R Fineman
- Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA.
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, USA.
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2
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Ding Z, Wei Y, Peng J, Wang S, Chen G, Sun J. The Potential Role of C-Reactive Protein in Metabolic-Dysfunction-Associated Fatty Liver Disease and Aging. Biomedicines 2023; 11:2711. [PMID: 37893085 PMCID: PMC10603830 DOI: 10.3390/biomedicines11102711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 09/27/2023] [Accepted: 09/27/2023] [Indexed: 10/29/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD), recently redefined as metabolic-dysfunction-associated fatty liver disease (MASLD), is liver-metabolism-associated steatohepatitis caused by nonalcoholic factors. NAFLD/MASLD is currently the most prevalent liver disease in the world, affecting one-fourth of the global population, and its prevalence increases with age. Current treatments are limited; one important reason hindering drug development is the insufficient understanding of the onset and pathogenesis of NAFLD/MASLD. C-reactive protein (CRP), a marker of inflammation, has been linked to NAFLD and aging in recent studies. As a conserved acute-phase protein, CRP is widely characterized for its host defense functions, but the link between CRP and NAFLD/MASLD remains unclear. Herein, we discuss the currently available evidence for the involvement of CRP in MASLD to identify areas where further research is needed. We hope this review can provide new insights into the development of aging-associated NAFLD biomarkers and suggest that modulation of CRP signaling is a potential therapeutic target.
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Affiliation(s)
- Zheng Ding
- Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing 100190, China
| | - Yuqiu Wei
- Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing 100190, China
| | - Jing Peng
- College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Siyu Wang
- Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing 100190, China
| | - Guixi Chen
- Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing 100190, China
| | - Jiazeng Sun
- Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing 100190, China
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3
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The effect of systemic levels of TNF-alpha and complement pathway activity on outcomes of VEGF inhibition in neovascular AMD. Eye (Lond) 2021; 36:2192-2199. [PMID: 34750590 PMCID: PMC9581945 DOI: 10.1038/s41433-021-01824-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 10/04/2021] [Accepted: 10/14/2021] [Indexed: 12/20/2022] Open
Abstract
Background/Objectives Systemic levels of pro-inflammatory cytokines and activated complement components affect the risk and/or progression of neovascular age-related macular degeneration (AMD). This study investigated the effect of serum pro-inflammatory cytokine levels and complement pathway activity on the clinical response to vascular endothelial growth factor (VEGF) inhibition in neovascular AMD. Methods Sixty-five patients with a new diagnosis of neovascular AMD were observed over a six-month period in a single-centre, longitudinal cohort study. At each visit, the visual acuity score (VAS), central macular thickness (CMT), serum levels of CRP, pro-inflammatory cytokines (TNF-α, IL-1β, IL-2, IL-6 and IL-8), and complement pathway activity were measured. Participant DNA samples were sequenced for six complement pathway single nucleotide polymorphisms (SNPs) associated with AMD. Results A statistically significant difference in VAS was observed for serum levels of TNF-α only: there was a gain in VAS (from baseline) of 1.37 for participants below the 1st quartile of mean concentration compared to a reduction of 2.71 for those above the 3rd quartile. Statistical significance was maintained after Bonferroni correction (P value set at <0.006). No significant differences in CMT were observed. In addition, statistically significant differences, maintained after Bonferroni correction, were observed in serum complement activity for participants with the following SNPs: CFH region (rs1061170), SERPING1 (rs2511989) and CFB (rs641153). Serum complement pathway components did not significantly affect VAS. Conclusions Lower serum TNF-α levels were associated with an increase in visual acuity after anti-VEGF therapy. This suggests that targeting pro-inflammatory cytokines may augment treatment for neovascular AMD.
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4
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Tan W, Zou J, Yoshida S, Jiang B, Zhou Y. The Role of Inflammation in Age-Related Macular Degeneration. Int J Biol Sci 2020; 16:2989-3001. [PMID: 33061811 PMCID: PMC7545698 DOI: 10.7150/ijbs.49890] [Citation(s) in RCA: 117] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 09/10/2020] [Indexed: 02/06/2023] Open
Abstract
Age-related macular degeneration (AMD) is a blinding eye disease which incidence gradually increases with age. Inflammation participates in AMD pathogenesis, including choroidal neovascularization and geographic atrophy. It is also a kind of self-protective regulation from injury for the eyes. In this review, we described inflammation in AMD pathogenesis, summarized the roles played by inflammation-related cytokines, including pro-inflammatory and anti-inflammatory cytokines, as well as leukocytes (macrophages, dendritic cells, neutrophils, T lymphocytes and B lymphocytes) in the innate or adaptive immunity in AMD. Possible clinical applications such as potential diagnostic biomarkers and anti-inflammatory therapies were also discussed. This review overviews the inflammation as a target of novel effective therapies in treating AMD.
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Affiliation(s)
- Wei Tan
- Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China.,Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan 410011, China
| | - Jingling Zou
- Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China.,Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan 410011, China
| | - Shigeo Yoshida
- Department of Ophthalmology, Kurume University School of Medicine, Kurume, Fukuoka 830-0011, Japan
| | - Bing Jiang
- Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China.,Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan 410011, China
| | - Yedi Zhou
- Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China.,Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan 410011, China
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5
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Zhou LB, Zhou YQ, Zhang XY. Blocking VEGF signaling augments interleukin-8 secretion via MEK/ERK/1/2 axis in human retinal pigment epithelial cells. Int J Ophthalmol 2020; 13:1039-1045. [PMID: 32685389 PMCID: PMC7321944 DOI: 10.18240/ijo.2020.07.04] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 04/23/2020] [Indexed: 12/13/2022] Open
Abstract
AIM To identify proangiogenic factors engaged in neovascular age-related macular degeneration (AMD) except vascular endothelial growth factor (VEGF) from human retinal pigment epithelial (hRPE) cells and investigate the underlying mechanisms. METHODS VEGF receptor 2 (VEGFR2) in ARPE-19 cells was depleted by siRNA transfection or overexpressed through adenovirus infection. The mRNA and the protein levels of interleukin-8 (IL-8) in ARPE-19 cells were measured by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay respectively. The protein levels of AKT, p-AKT, MEK, p-MEK, ERK1/2, p-ERK1/2, JNK, p-JNK, p38 and p-p38 were detected by Western blotting. A selective chemical inhibitor, LY3214996, was employed to inhibit phosphorylation of ERK1/2. Cell viability was determined by MTT assay. RESULTS Knockdown of VEGFR2 in ARPE-19 cells robustly augmented IL-8 production at both the mRNA and the protein levels. Silencing VEGFR2 substantially enhanced phosphorylation of MEK and ERK1/2 while exerted no effects on phosphorylation of AKT, JNK and p38. Inhibiting ERK1/2 phosphorylation by LY3214996 reversed changes in VEGFR2 knockdown-induced IL-8 upregulation at the mRNA and the protein levels with no effects on cell viability. VEGFR2 overexpression significantly reduced IL-8 generation at the mRNA and the protein levels. CONCLUSION Blockade of VEGF signaling augments IL-8 secretion via MEK/ERK1/2 axis and overactivation of VEGF pathway decreases IL-8 production in hRPE cells. Upregulated IL-8 expression after VEGF signaling inhibition in hRPE cells may be responsible for being incompletely responsive to anti-VEGF remedy in neovascular AMD, and IL-8 may serve as an alternative therapeutic target for neovascular AMD.
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Affiliation(s)
- Lin-Bin Zhou
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, Guangdong Province, China
| | - Ye-Qi Zhou
- Soochow University Affiliated Children's Hospital, Suzhou 215123, Jiangsu Province, China
| | - Xin-Yu Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, Guangdong Province, China
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6
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Fang Z, Lv J, Wang J, Qin Q, He J, Wang M, Zhou G, Liu G, Zhong F, Zheng Y, Lan HY, Wang Q. C-Reactive Protein Promotes the Activation of Fibroblast-Like Synoviocytes From Patients With Rheumatoid Arthritis. Front Immunol 2020; 11:958. [PMID: 32508836 PMCID: PMC7251027 DOI: 10.3389/fimmu.2020.00958] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 04/23/2020] [Indexed: 01/23/2023] Open
Abstract
Objective: To evaluate the biological effect and mechanisms of C-reactive protein (CRP) on the activation of fibroblast-like synoviocytes (FLSs) from patients with rheumatoid arthritis (RA). Study design: To understand if CRP is involved in RA, expression of CRP and its receptors CD32/64 was examined in synovial tissues from RA patients and normal controls. In vitro, the potential role and mechanisms of CRP in FLS proliferation and invasion, expression of pro-inflammatory cytokines, and activation of signaling pathways were investigated in both RA - FLS and a normal human fibroblast-like synoviocyte line (HFLS). Results: Compared to normal controls, synovial tissues from 21 RA patients exhibited highly activated CRP signaling, particularly by FLSs as identified by 65% of CRP-expressing cells being CRP+vimentin+ and CD32/64+vimentin+ cells. In vitro, FLSs from RA patients, but not HFLS, showed highly reactive to CRP by largely increasing proliferative and invasive activities and expressing pro-inflammatory cytokines and chemokines, including CCL2, CXCL8, IL-6, and MMP2/9. All these changes were blocked largely by a neutralizing antibody to CD32 and, to a less extent by the anti-CD64 antibody, revealing CD32 as a primary mechanism of CRP signaling during synovial inflammation. Further studies revealed that CRP also induced synovial inflammation differentially via CD32/CD64- NF-κB or p38 pathways as blockade of CRP-CD32-NF-κB signaling inhibited CXCL8, CCL2, IL-6, whereas CRP induced RA-FLS invasiveness through CD32-p38 and MMP9 expression via the CD64-p38-dependent mechanism. Conclusions: CRP signaling is highly activated in synovial FLSs from patients with RA. CRP can induce synovial inflammation via mechanisms associated with activation of CD32/64-p38 and NF-κB signaling.
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Affiliation(s)
- Zhengyu Fang
- Department of Rheumatism and Immunology, Peking University Shenzhen Hospital, Shenzhen, China.,Biomedical Research Institute, Shenzhen Peking University - The Hong Kong University of Science and Technology Medical Center, Shenzhen, China
| | - Jiyang Lv
- Department of Rheumatism and Immunology, Peking University Shenzhen Hospital, Shenzhen, China
| | - Jing Wang
- Department of Rheumatism and Immunology, Peking University Shenzhen Hospital, Shenzhen, China
| | - Qingxia Qin
- Department of Rheumatism and Immunology, Peking University Shenzhen Hospital, Shenzhen, China
| | - Juan He
- Department of Rheumatism and Immunology, Peking University Shenzhen Hospital, Shenzhen, China
| | - Meiying Wang
- Department of Rheumatism and Immunology, Peking University Shenzhen Hospital, Shenzhen, China
| | - Gengmin Zhou
- Department of Rheumatism and Immunology, Peking University Shenzhen Hospital, Shenzhen, China
| | - Guoyu Liu
- Biomedical Research Institute, Shenzhen Peking University - The Hong Kong University of Science and Technology Medical Center, Shenzhen, China
| | - Fubo Zhong
- Biomedical Research Institute, Shenzhen Peking University - The Hong Kong University of Science and Technology Medical Center, Shenzhen, China
| | - Yadan Zheng
- Biomedical Research Institute, Shenzhen Peking University - The Hong Kong University of Science and Technology Medical Center, Shenzhen, China
| | - Hui-Yao Lan
- Department of Medicine and Therapeutics, Li Ka Shing Institute of Health Sciences, and Lui Che Woo Institute of Innovative Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Qingwen Wang
- Department of Rheumatism and Immunology, Peking University Shenzhen Hospital, Shenzhen, China
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7
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Chirco KR, Potempa LA. C-Reactive Protein As a Mediator of Complement Activation and Inflammatory Signaling in Age-Related Macular Degeneration. Front Immunol 2018; 9:539. [PMID: 29599782 PMCID: PMC5862805 DOI: 10.3389/fimmu.2018.00539] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 03/02/2018] [Indexed: 12/13/2022] Open
Abstract
Age-related macular degeneration (AMD) is a devastating neurodegenerative disease affecting millions worldwide. Complement activation, inflammation, and the loss of choroidal endothelial cells have been established as key factors in both normal aging and AMD; however, the exact mechanisms for these events have yet to be fully uncovered. Herein, we provide evidence that the prototypic acute phase reactant, C-reactive protein (CRP), contributes to AMD pathogenesis. We discuss serum CRP levels as a risk factor for disease, immunolocalization of distinct forms of CRP in the at-risk and diseased retina, and direct effects of CRP on ocular tissue. Furthermore, we discuss the complement system as it relates to AMD pathophysiology, provide a model for the role of CRP in this disease, and outline current therapies being developed and tested to treat AMD patients.
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8
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Gao M, Wu S, Ji J, Zhang J, Liu Q, Yue Y, Liu L, Liu X, Liu W. The influence of actin depolymerization induced by Cytochalasin D and mechanical stretch on interleukin-8 expression and JNK phosphorylation levels in human retinal pigment epithelial cells. BMC Ophthalmol 2017; 17:43. [PMID: 28388885 PMCID: PMC5384187 DOI: 10.1186/s12886-017-0437-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 04/04/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND This study explores the role of actin cytoskeleton depolymerization induced by Cytochalasin D and mechanical stretch on the interleukin-8 (IL-8) expression and c-jun N-terminal kinase (JNK) phosphorylation levels in human retinal pigment epithelial (RPE) cells. METHODS A Flexcell FX-5000 Tension system was used to apply cyclic stretch to cultured human RPE cells (ARPE-19) at 0.33 Hz with 20% elongation for 0 h, 6 h or 24 h. The cells were stretched alone or pre-treated with Cytochalasin D. The redistribution of the actin cytoskeleton was evaluated using phalloidin immunofluorescence staining. The protein expression levels of IL-8 and JNK in the RPE cells were determined via Western blotting. RESULTS The cells in the control groups displayed abundant and uniform phalloidin staining. After exposure to mechanical stretch for 24 h, phalloidin staining revealed an unclear and irregular actin cytoskeleton. In all Cytochalasin D-treated cells, the shrinkage and disruption of the cytoskeletal structure was observed regardless of mechanical stress. The stimulation of the RPE cells with cyclic stretch alone did not induce a significant increase in IL-8 expression and JNK phosphorylation levels, which were similar to those of the control groups. After pre-treatment with Cytochalasin D alone, IL-8 expression and JNK phosphorylation levels were not significantly different at 6 h but were significantly increased by approximately 1.2-fold (1.18 ± 0.05; P<0.01) and 3.0-fold (3.01 ± 0.02; P<0.01) at 24 h, respectively. After the pre-incubation of the RPE cells with Cytochalasin D followed by exposure to cyclic stretch, IL-8 expression and JNK phosphorylation levels increased by approximately 1.3-fold (1.31 ± 0.02; P<0.01) and 1.3-fold (1.31 ± 0.02; P<0.01) at 6 h, respectively, and by 1.7-fold (1.69 ± 0.06; P<0.01) and 3.2-fold (3.21 ± 0.12; P<0.01) at 24 h, respectively. CONCLUSIONS This study demonstrates that disruption of actin polymerization by cytochalasin D and mechanical stretch upregulates interleukin-8 expression and JNK phosphorylation levels in human RPE cells, which indicates that the integrity of the actin cytoskeleton may play important roles in the pro-inflammatory processes in RPE cells.
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Affiliation(s)
- Meng Gao
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing, China
| | - Shen Wu
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing, China
| | - Jing Ji
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - JingXue Zhang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing, China
| | - Qian Liu
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing, China
| | - YanKun Yue
- Department of Ophthalmology, Beijing Fuxing Hospital, Capital Medical University, Beijing, China
| | - Lu Liu
- Department of Ophthalmology, Beijing Fuxing Hospital, Capital Medical University, Beijing, China
| | - XinXin Liu
- Department of Ophthalmology, Kailuan General Hospital, Tangshan, China
| | - Wu Liu
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing, China.
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9
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Lambert NG, ElShelmani H, Singh MK, Mansergh FC, Wride MA, Padilla M, Keegan D, Hogg RE, Ambati BK. Risk factors and biomarkers of age-related macular degeneration. Prog Retin Eye Res 2016; 54:64-102. [PMID: 27156982 DOI: 10.1016/j.preteyeres.2016.04.003] [Citation(s) in RCA: 230] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 04/01/2016] [Accepted: 04/12/2016] [Indexed: 02/03/2023]
Abstract
A biomarker can be a substance or structure measured in body parts, fluids or products that can affect or predict disease incidence. As age-related macular degeneration (AMD) is the leading cause of blindness in the developed world, much research and effort has been invested in the identification of different biomarkers to predict disease incidence, identify at risk individuals, elucidate causative pathophysiological etiologies, guide screening, monitoring and treatment parameters, and predict disease outcomes. To date, a host of genetic, environmental, proteomic, and cellular targets have been identified as both risk factors and potential biomarkers for AMD. Despite this, their use has been confined to research settings and has not yet crossed into the clinical arena. A greater understanding of these factors and their use as potential biomarkers for AMD can guide future research and clinical practice. This article will discuss known risk factors and novel, potential biomarkers of AMD in addition to their application in both academic and clinical settings.
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Affiliation(s)
- Nathan G Lambert
- Ambati Lab, John A. Moran Eye Center, 65 Mario Capecchi Drive, Salt Lake City, UT, USA; Department of Ophthalmology & Visual Sciences, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, USA.
| | - Hanan ElShelmani
- Ocular Development and Neurobiology Research Group, Zoology Department, School of Natural Sciences, University of Dublin, Trinity College, Dublin 2, Ireland.
| | - Malkit K Singh
- Ambati Lab, John A. Moran Eye Center, 65 Mario Capecchi Drive, Salt Lake City, UT, USA; Department of Ophthalmology & Visual Sciences, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, USA.
| | - Fiona C Mansergh
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland.
| | - Michael A Wride
- Ocular Development and Neurobiology Research Group, Zoology Department, School of Natural Sciences, University of Dublin, Trinity College, Dublin 2, Ireland.
| | - Maximilian Padilla
- Ambati Lab, John A. Moran Eye Center, 65 Mario Capecchi Drive, Salt Lake City, UT, USA; Department of Ophthalmology & Visual Sciences, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, USA.
| | - David Keegan
- Mater Misericordia Hospital, Eccles St, Dublin 7, Ireland.
| | - Ruth E Hogg
- Centre for Experimental Medicine, Institute of Clinical Science Block A, Grosvenor Road, Belfast, Co.Antrim, Northern Ireland, UK.
| | - Balamurali K Ambati
- Ambati Lab, John A. Moran Eye Center, 65 Mario Capecchi Drive, Salt Lake City, UT, USA; Department of Ophthalmology & Visual Sciences, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, USA.
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10
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Molins B, Fuentes-Prior P, Adán A, Antón R, Arostegui JI, Yagüe J, Dick AD. Complement factor H binding of monomeric C-reactive protein downregulates proinflammatory activity and is impaired with at risk polymorphic CFH variants. Sci Rep 2016; 6:22889. [PMID: 26961257 PMCID: PMC4785391 DOI: 10.1038/srep22889] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 02/23/2016] [Indexed: 11/30/2022] Open
Abstract
Inflammation and immune-mediated processes are pivotal to the pathogenic progression of age-related macular degeneration (AMD). Although plasma levels of C-reactive protein (CRP) have been shown to be associated with an increased risk for AMD, the pathophysiological importance of the prototypical acute-phase reactant in the etiology of the disease is unknown, and data regarding the exact role of CRP in ocular inflammation are limited. In this study, we provide mechanistic insight into how CRP contributes to the development of AMD. In particular, we show that monomeric CRP (mCRP) but not the pentameric form (pCRP) upregulates IL-8 and CCL2 levels in retinal pigment epithelial cells. Further, we show that complement factor H (FH) binds mCRP to dampen its proinflammatory activity. FH from AMD patients carrying the “risk” His402 polymorphism displays impaired binding to mCRP, and therefore proinflammatory effects of mCRP remain unrestrained.
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Affiliation(s)
- Blanca Molins
- Institut d'Investigacions Biomèdiques Agustí Pi i Sunyer (IDIBAPS), Hospital Clínic de Barcelona, 08028 Barcelona, Spain
| | - Pablo Fuentes-Prior
- Molecular Bases of Disease, Biomedical Research Institute Sant Pau (IIB Sant Pau), 08025 Barcelona, Spain.,Universitat Autònoma de Barcelona, 08193 Bellaterra (Cerdanyola del Vallès), Spain
| | - Alfredo Adán
- Institut d'Investigacions Biomèdiques Agustí Pi i Sunyer (IDIBAPS), Hospital Clínic de Barcelona, 08028 Barcelona, Spain
| | - Rosa Antón
- Molecular Bases of Disease, Biomedical Research Institute Sant Pau (IIB Sant Pau), 08025 Barcelona, Spain
| | - Juan I Arostegui
- Department of Immunology-CDB, Hospital Clínic-IDIBAPS, 08028 Barcelona, Spain
| | - Jordi Yagüe
- Department of Immunology-CDB, Hospital Clínic-IDIBAPS, 08028 Barcelona, Spain
| | - Andrew D Dick
- Academic Unit of Ophthalmology, School of Clinical Sciences and School of Cellular and Molecular Medicine, University of Bristol, Bristol, BS8 1TH, UK.,National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital and University College London Institute of Ophthalmology, London, EC1V 2PD, UK
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11
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Dithmer M, Hattermann K, Pomarius P, Aboul Naga SH, Meyer T, Mentlein R, Roider J, Klettner A. The role of Fc-receptors in the uptake and transport of therapeutic antibodies in the retinal pigment epithelium. Exp Eye Res 2016; 145:187-205. [PMID: 26773870 DOI: 10.1016/j.exer.2015.12.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 11/11/2015] [Accepted: 12/31/2015] [Indexed: 10/22/2022]
Abstract
In the ophthalmological clinic, intravitreally applied antibodies or Fc-containing fusion proteins are frequently used, but the biology and pharmacokinetics of these therapeutics in the retina are not well understood. We have previously shown intracellular uptake of Fc-containing molecules in RPE cells. In this study, we investigated the involvement of Fc-receptors, both Fcγ-receptors and the neonatal Fc-receptor (FcRn) in the uptake and intracellular trafficking of the VEGF-antagonists bevacizumab, aflibercept and the anti-CD20 antibody rituximab in three different model systems, primary porcine RPE cells, ARPE-19 cells and porcine RPE/choroid explants. The expression of Fcγ-receptors was tested in primary porcine RPE cells, and the expression of Fcγ-receptors I and II could be shown in RT-PCR and qRT-PCR, while the expression of FcRn was additionally confirmed in Western blot and immunocytochemistry. All three compounds, bevacizumab, rituximab and aflibercept, were taken up into the cells and displayed a characteristic time-dependent pattern, as shown in Western blot and immunohistochemistry. The uptake was not altered by the inhibition of Fcγ-receptors using different inhibitors (TruStain FcX, genistein, R406). However, the inhibition of FcRn with an antagonistic antibody reduced intracellular IgG in porcine RPE cells (rituximab) and ARPE-19 cells (bevacizumab, rituximab). Colocalisations between the tested compounds and myosin7a could be found. In addition, limited colocalization with FcRn and the tested compounds, as well as triple localization between compound, FcRn and myosin7a could be detected, indicating a role of myosin7a in FcRn mediated transport. However, the colocalizations are restricted to small fractions of the Fc-containing compounds. Furthermore, the FcRn is mainly found in the membrane section, where only minute amounts of the Fc-containing compounds are seen, suggesting a limited interaction. An apical to choroidal transport of IgG through the RPE/choroid can be found in RPE/choroid explants. Inhibition of FcRn increases the amount of bevacizumab found on the choroidal side, suggesting a role of FcRn in the recycling of bevacizumab. In conclusion, our data indicate a role for FcRn, but not Fcγ-receptors, in the uptake and transport of Fc-containing molecules in the RPE and indicate a recycling function of FcRn in the retina.
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Affiliation(s)
- Michaela Dithmer
- University of Kiel, University Medical Center, Department of Ophthalmology, Kiel, Germany
| | | | - Prasti Pomarius
- University of Kiel, University Medical Center, Department of Ophthalmology, Kiel, Germany
| | - Shereen Hassan Aboul Naga
- University of Kiel, University Medical Center, Department of Ophthalmology, Kiel, Germany; University of Cairo, Kasr Al-Aini Faculty of Medicine, Cairo, Egypt
| | - Tim Meyer
- Department of Gastroenterology, Charite University Clinic, Berlin, Germany
| | - Rolf Mentlein
- University of Kiel, Department of Anatomy, Kiel, Germany
| | - Johann Roider
- University of Kiel, University Medical Center, Department of Ophthalmology, Kiel, Germany
| | - Alexa Klettner
- University of Kiel, University Medical Center, Department of Ophthalmology, Kiel, Germany.
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Lazzeri S, Orlandi P, Piaggi P, Sartini MS, Casini G, Guidi G, Figus M, Fioravanti A, Di Desidero T, Ripandelli G, Parravano M, Varano M, Nardi M, Bocci G. IL-8 and VEGFR-2 polymorphisms modulate long-term functional response to intravitreal ranibizumab in exudative age-related macular degeneration. Pharmacogenomics 2015; 17:35-9. [PMID: 26653034 DOI: 10.2217/pgs.15.153] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
AIM To investigate possible associations between VEGFR-2 and IL-8 gene SNPs and 1-year response to intravitreal ranibizumab for exudative age-related macular degeneration. MATERIALS & METHODS Sixty-four eyes underwent a loading phase of three monthly intravitreal injections of ranibizumab 0.5 mg/0.05 ml followed by Pro Re Nata retreatment. VEGFR-2 rs2071559 (-604 A/G) and IL-8 rs4073 (-251 A/T) were analyzed. RESULTS Ranibizumab was significantly more effective as measured by visual acuity in patients harboring the IL-8 rs4073 TT genotype (p = 0.045), whereas patients carrying the VEGFR-2 rs2071559 CC genotype revealed better functional response as measured by mean retinal sensitivity (p = 0.034). CONCLUSION IL-8 rs4073 and VEGFR-2 rs2071559 genotypes may represent important molecular determinants to modulate final outcomes in neovascular age-related macular degeneration patients.
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Affiliation(s)
- Stefano Lazzeri
- Ophthalmology Unit, University of Pisa, Pisa, Italy.,Fondazione G. B. Bietti, IRCCS Rome, Italy
| | - Paola Orlandi
- Division of Pharmacology, Department of Clinical & Experimental Medicine, University of Pisa, Pisa, Italy
| | - Paolo Piaggi
- Department of Endocrinology & Metabolism, University of Pisa, Pisa, Italy.,Department of Energy & Systems Engineering, University of Pisa, Pisa, Italy
| | | | | | | | | | - Anna Fioravanti
- Division of Pharmacology, Department of Clinical & Experimental Medicine, University of Pisa, Pisa, Italy
| | - Teresa Di Desidero
- Division of Pharmacology, Department of Clinical & Experimental Medicine, University of Pisa, Pisa, Italy
| | | | | | | | - Marco Nardi
- Ophthalmology Unit, University of Pisa, Pisa, Italy
| | - Guido Bocci
- Division of Pharmacology, Department of Clinical & Experimental Medicine, University of Pisa, Pisa, Italy
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Hautamäki A, Seitsonen S, Holopainen JM, Moilanen JA, Kivioja J, Onkamo P, Järvelä I, Immonen I. The genetic variant rs4073 A→T of the Interleukin-8 promoter region is associated with the earlier onset of exudative age-related macular degeneration. Acta Ophthalmol 2015; 93:726-33. [PMID: 26154559 PMCID: PMC4758390 DOI: 10.1111/aos.12799] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 05/31/2015] [Indexed: 12/13/2022]
Abstract
Purpose To study the association of the single nucleotide polymorphism (SNP) rs4073 in the interleukin‐8 (IL‐8) promoter region with the diagnosis and age of onset of exudative age‐related macular degeneration (AMD) in association with the known genetic risk factors for AMD and tobacco smoking. Methods Medical records, smoking history and angiograms or fundus photographs of 301 patients with exudative AMD, 72 patients with dry AMD and 119 control subjects were analysed retrospectively. The associations of IL‐8 rs4073 A→T, CFH rs1061170 T→C, ARMS2 rs10490924 G→T and C3 rs2230199 C→G SNPs with the presence of AMD and with the age of onset of exudative AMD were analysed. Results Younger age of exudative AMD onset was associated with the homozygous AA genotype of IL‐8 rs4073 (p = 0.009, Mann–Whitney U‐test), CC genotype of CFH rs1061170 (p = 0.016), TT genotype of ARMS2 rs10490924 (p = 0.001) and with current smoking (p = 0.002). The risk alleles C in CFH rs1061170 (p < 0.0001, Pearson chi‐square) and T in ARMS2 rs10490924 (p < 0.0001), as well as smoking (p < 0.0001), were more prevalent in AMD patients compared with controls. No association was found between the IL‐8 rs4073 genotype and the presence of AMD. Conclusion Out of the factors associated with the earlier onset of exudative AMD, only the genotype of IL‐8 rs4073 did not appear as a risk factor for AMD in general. IL‐8 may have a role in accelerating the development of the choroidal neovascularization in exudative AMD.
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Affiliation(s)
- Asta Hautamäki
- Department of Ophthalmology University of Helsinki and Helsinki University Hospital Helsinki Finland
| | - Sanna Seitsonen
- Department of Ophthalmology University of Helsinki and Helsinki University Hospital Helsinki Finland
| | - Juha M. Holopainen
- Department of Ophthalmology University of Helsinki and Helsinki University Hospital Helsinki Finland
| | - Jukka A. Moilanen
- Department of Ophthalmology University of Helsinki and Helsinki University Hospital Helsinki Finland
| | - Jarno Kivioja
- Department of Medical Genetics University of Helsinki Helsinki Finland
| | - Päivi Onkamo
- Department of Biological and Environmental Sciences University of Helsinki Helsinki Finland
| | - Irma Järvelä
- Department of Medical Genetics University of Helsinki Helsinki Finland
| | - Ilkka Immonen
- Department of Ophthalmology University of Helsinki and Helsinki University Hospital Helsinki Finland
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14
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Whitmore SS, Sohn EH, Chirco KR, Drack AV, Stone EM, Tucker BA, Mullins RF. Complement activation and choriocapillaris loss in early AMD: implications for pathophysiology and therapy. Prog Retin Eye Res 2015; 45:1-29. [PMID: 25486088 PMCID: PMC4339497 DOI: 10.1016/j.preteyeres.2014.11.005] [Citation(s) in RCA: 159] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Revised: 11/19/2014] [Accepted: 11/25/2014] [Indexed: 12/24/2022]
Abstract
Age-related macular degeneration (AMD) is a common and devastating disease that can result in severe visual dysfunction. Over the last decade, great progress has been made in identifying genetic variants that contribute to AMD, many of which lie in genes involved in the complement cascade. In this review we discuss the significance of complement activation in AMD, particularly with respect to the formation of the membrane attack complex in the aging choriocapillaris. We review the clinical, histological and biochemical data that indicate that vascular loss in the choroid occurs very early in the pathogenesis of AMD, and discuss the potential impact of vascular dropout on the retinal pigment epithelium, Bruch's membrane and the photoreceptor cells. Finally, we present a hypothesis for the pathogenesis of early AMD and consider the implications of this model on the development of new therapies.
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Affiliation(s)
- S Scott Whitmore
- The Stephen A. Wynn Institute for Vision Research, The University of Iowa, United States; Department of Ophthalmology and Visual Sciences, The University of Iowa, United States
| | - Elliott H Sohn
- The Stephen A. Wynn Institute for Vision Research, The University of Iowa, United States; Department of Ophthalmology and Visual Sciences, The University of Iowa, United States
| | - Kathleen R Chirco
- The Stephen A. Wynn Institute for Vision Research, The University of Iowa, United States; Department of Ophthalmology and Visual Sciences, The University of Iowa, United States
| | - Arlene V Drack
- The Stephen A. Wynn Institute for Vision Research, The University of Iowa, United States; Department of Ophthalmology and Visual Sciences, The University of Iowa, United States
| | - Edwin M Stone
- The Stephen A. Wynn Institute for Vision Research, The University of Iowa, United States; Department of Ophthalmology and Visual Sciences, The University of Iowa, United States
| | - Budd A Tucker
- The Stephen A. Wynn Institute for Vision Research, The University of Iowa, United States; Department of Ophthalmology and Visual Sciences, The University of Iowa, United States
| | - Robert F Mullins
- The Stephen A. Wynn Institute for Vision Research, The University of Iowa, United States; Department of Ophthalmology and Visual Sciences, The University of Iowa, United States
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15
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Toxic effects of extracellular histones and their neutralization by vitreous in retinal detachment. J Transl Med 2014; 94:569-85. [PMID: 24614198 DOI: 10.1038/labinvest.2014.46] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 01/08/2014] [Accepted: 02/05/2014] [Indexed: 12/22/2022] Open
Abstract
Histones are DNA-binding proteins and are involved in chromatin remodeling and regulation of gene expression. Histones can be released after tissue injuries, and the extracellular histones cause cellular damage and organ dysfunction. Regardless of their clinical significance, the role and relevance of histones in ocular diseases are unknown. We studied the role of histones in eyes with retinal detachment (RD). Vitreous samples were collected during vitrectomy, and the concentration of histone H3 was measured by enzyme-linked immunosorbent assay. The location of the histones and related molecules was examined in a rat RD model. The release of histones and their effects on rat retinal progenitor cells R28 and ARPE-19 were evaluated in vitro. In addition, the protective role of the vitreous body against histones was tested. The intravitreal concentration of histones was higher in eyes with RD (mean, 30.9 ± 9.8 ng/ml) than in control eyes (below the limit of detection, P<0.05). In the rat RD model, histone H3 was observed on the outer side of the detached retina and was associated with photoreceptor death. Histone H3 was released from cultured R28 by oxidative stress. Histones at a concentration 10 μg/ml induced the production of interleukin-8 in ARPE-19 cells (2.5-fold increase, P<0.05) that was mediated through the ERK1/2- and p38 MAPK-dependent pathways and Toll-like receptor 4. Histones were toxic to cells at concentrations of ≥ 20 μg/ml. Vitreous body or hyaluronan decreased toxicity of histones by inhibiting diffusion of histones. These results indicate that histones are released from retinas with RD and may modulate the subretinal microenvironment by functioning as damage-associated molecular pattern molecules, thereby inducing proinflammatory cytokines or cell toxicity. In addition, the important role of the vitreous body and hyaluronan in protecting the retina from these toxic effects is suggested.
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Interleukin 8 promoter polymorphism predicts the initial response to bevacizumab treatment for exudative age-related macular degeneration. Retina 2014; 33:1815-27. [PMID: 23584701 DOI: 10.1097/iae.0b013e318285cf92] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
PURPOSE To study the association of single-nucleotide polymorphisms of interleukin 8, vascular endothelial growth factor, erythropoietin, complement factor H, complement component C3, and LOC387715 genes with the response to bevacizumab treatment in exudative age-related macular degeneration. METHODS Clinical records, smoking history, optical coherence tomography, and angiographies of 96 bevacizumab-treated exudative age-related macular degeneration patients were analyzed retrospectively. Blood DNA was collected. Based on the disappearance of intra- or subretinal fluid in optical coherence tomography, patients were graded as responders, partial responders, or nonresponders after 3 initial treatment visits and a median time of 3.5 months. RESULTS Interleukin 8 promoter polymorphism -251A/T was significantly associated with persisting fluid in optical coherence tomography. The A allele was more frequent in nonresponders than in responders (P = 0.033). In multivariate modeling, the AA genotype of -251A/T (P = 0.043) and occult (P = 0.042) or predominantly classic (P = 0.040) lesions predicted poorer outcome. Visual acuity change was better in responders than in nonresponders (P = 0.006). Baseline lesion size (P = 0.006) and retinal cysts after the treatment (P < 0.001) correlated with less visual acuity gain. CONCLUSION The A allele and the homozygous AA genotype of interleukin 8 -251A/T were associated with anatomical nonresponse to bevacizumab treatment.
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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: 170] [Impact Index Per Article: 15.5] [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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Chen CL, Liang CM, Chen YH, Tai MC, Lu DW, Chen JT. Bevacizumab modulates epithelial-to-mesenchymal transition in the retinal pigment epithelial cells via connective tissue growth factor up-regulation. Acta Ophthalmol 2012; 90:e389-98. [PMID: 22712616 DOI: 10.1111/j.1755-3768.2012.02426.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE To investigate the effect of bevacizumab treatment on connective tissue growth factor (CTGF) expression and the induction of epithelial-to-mesenchymal transition in ARPE-19 cells and human donor retinal pigment epithelium (HRPE) cells in vitro. METHODS We quantitated the protein and gene expression level of CTGF by ELISA. The effect of Fc-Fc receptor (Fc-FcR) interaction on CTGF expression was evaluated by CD64 siRNA silencing. Expression of epithelial-to-mesenchymal transition markers, alpha-smooth muscle actin (α-SMA) and zona occludens protein (ZO-1) was evaluated by Western blot. Cell migration and collagen gel contraction assay were examined by light microscopy, and collagen production was measured by ELISA. RESULTS Bevacizumab stimulation increased CTGF expression in ARPE-19 and HRPE cells in a dose-dependent manner. CD64 gene silencing inhibited the effect of bevacizumab-induced CTGF up-regulation. Bevacizumab increased the expression of α-SMA and decreased the expression of ZO-1 in ARPE-19 cells. Bevacizumab also caused the release of type-1 collagen and increased cell migration and contraction of collagen. CONCLUSIONS Bevacizumab exerts pro-fibrotic effects on human RPE cells at clinical doses by up-regulation of CTGF expression via an Fc-FcR interaction. This effect of bevacizumab may be one of the underlying mechanisms involved in age-related macular degeneration therapy or intravitreal bevacizumab-associated complications.
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Affiliation(s)
- Ching-Long Chen
- Graduate Institute of Medical Science, National Defense Medical Center, Taipei, Taiwan
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Liu J, Jha P, Lyzogubov VV, Tytarenko RG, Bora NS, Bora PS. Relationship between complement membrane attack complex, chemokine (C-C motif) ligand 2 (CCL2) and vascular endothelial growth factor in mouse model of laser-induced choroidal neovascularization. J Biol Chem 2011; 286:20991-1001. [PMID: 21515678 DOI: 10.1074/jbc.m111.226266] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The present study investigated the interactions among the complement membrane attack complex (MAC), CCL2, and VEGF that occur in vivo during the development of choroidal neovascularization (CNV). We first investigated the sequential expression of MAC, CCL2, and VEGF during laser-induced CNV in C57BL/6 mice. Increased MAC deposition was detected at 1 h, CCL2 increased at 3 h, and VEGF was up-regulated at day 3 post-laser treatment. These results suggested that during laser-induced CNV, MAC, CCL2 and VEGF are formed and/or expressed in the following order: MAC → CCL2 → VEGF. To determine the cross-talk between MAC, CCL2, and VEGF during laser-induced CNV, neutralizing antibodies were injected both systemically and locally to block the bioactivity of each molecule. Blocking MAC formation inhibited CCL2 and VEGF expression and also limited CNV formation, whereas neutralization of CCL2 bioactivity did not affect MAC deposition; however, it reduced VEGF expression and CNV formation. When bioactivity of VEGF was blocked, CNV formation was significantly inhibited, but MAC deposition was not affected. Together, our results demonstrate that MAC is an upstream mediator and effect of MAC on the development of laser-induced CNV can be attributed to its direct effect on VEGF as well as its effect on VEGF that is mediated by CCL2. Understanding the interplay between immune mediators is critical to gain insight into the pathogenesis of CNV.
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Affiliation(s)
- Juan Liu
- Department of Ophthalmology, University of Arkansas for Medical Sciences, Little Rock, Arizona 72205, USA
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Salminen A, Kauppinen A, Hyttinen JM, Toropainen E, Kaarniranta K. Endoplasmic reticulum stress in age-related macular degeneration: trigger for neovascularization. Mol Med 2010; 16:535-42. [PMID: 20683548 DOI: 10.2119/molmed.2010.00070] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Accepted: 07/26/2010] [Indexed: 12/18/2022] Open
Abstract
Age-related macular degeneration (AMD) can be classified into two main categories: the atrophic, dry form and the exudative, wet form. The crucial difference between dry and wet AMD is the development of choroidal neovascularization in wet AMD. One fundamental cause of the neovascularization is the increased expression of VEGF (vascular endothelial growth factor) in retinal pigment epithelial cells. Progression of AMD is linked to augmentation of cellular stress, for example, oxidative stress, proteotoxic stress, inflammation and hypoxia. All these conditions can trigger stress in endoplasmic reticulum (ER), which maintains protein quality control in cells. ER stress induces the unfolded protein response (UPR) via IRE1 (inositol-requiring protein-1), PERK (protein kinase RNA-like ER kinase) and ATF6 (activating transcription factor-6) transducers. UPR signaling is a double-edged sword, that is, it can restore cellular homeostasis as far as possible, but ultimately may lead to chronic, overwhelming stress that can cause apoptotic cell death. Interestingly, ER stress is a well-known inducer of angiogenesis in cancer. Moreover, stress conditions associated with the progress of AMD can induce the expression of VEGF. We discuss the role of ER stress in the regulation of neovascularization and the conversion of dry AMD to its wet, detrimental counterpart.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, University of Eastern Finland, Kuopio, Finland.
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