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"Endothelial Antibody Factory" at the Blood Brain Barrier: Novel Approach to Therapy of Neurodegenerative Diseases. Pharmaceutics 2022; 14:pharmaceutics14071418. [PMID: 35890313 PMCID: PMC9320725 DOI: 10.3390/pharmaceutics14071418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 06/24/2022] [Accepted: 06/29/2022] [Indexed: 02/01/2023] Open
Abstract
The failures of anti-β-amyloid immunotherapies suggested that the very low fraction of injected antibodies reaching the brain parenchyma due to the filtering effect of the BBB may be a reason for the lack of therapeutic effect. However, there is no treatment, as yet, for the amyotrophic lateral sclerosis (ALS) despite substantial evidence existing of the involvement of TDP-43 protein in the evolution of ALS. To circumvent this filtering effect, we have developed a novel approach to facilitate the penetration of antibody fragments (Fabs) into the brain parenchyma. Leveraging the homing properties of endothelial progenitor cells (EPCs), we transfected, ex vivo, such cells with vectors encoding anti-β-amyloid and anti-TDP43 Fabs turning them into an “antibody fragment factory”. When injected these cells integrate into the BBB, where they secrete anti-TDP43 Fabs. The results showed the formation of tight junctions between the injected engineered EPCs and the unlabeled resident endothelial cells. When the EPCs were further modified to express the anti-TDP43 Fab, we could observe integration of these cells into the vasculature and the secretion of Fabs. Results confirm that production and secretion of Fabs at the BBB level leads to their migration to the brain parenchyma where they might exert a therapeutic effect.
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Hasan R, Humphrey J, Bettencourt C, Newcombe J, Lashley T, Fratta P, Raj T. Transcriptomic analysis of frontotemporal lobar degeneration with TDP-43 pathology reveals cellular alterations across multiple brain regions. Acta Neuropathol 2022; 143:383-401. [PMID: 34961893 PMCID: PMC10725322 DOI: 10.1007/s00401-021-02399-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 12/07/2021] [Accepted: 12/10/2021] [Indexed: 12/28/2022]
Abstract
Frontotemporal lobar degeneration (FTLD) is a group of heterogeneous neurodegenerative disorders affecting the frontal and temporal lobes of the brain. Nuclear loss and cytoplasmic aggregation of the RNA-binding protein TDP-43 represents the major FTLD pathology, known as FTLD-TDP. To date, there is no effective treatment for FTLD-TDP due to an incomplete understanding of the molecular mechanisms underlying disease development. Here we compared postmortem tissue RNA-seq transcriptomes from the frontal cortex, temporal cortex, and cerebellum between 28 controls and 30 FTLD-TDP patients to profile changes in cell-type composition, gene expression and transcript usage. We observed downregulation of neuronal markers in all three regions of the brain, accompanied by upregulation of microglia, astrocytes, and oligodendrocytes, as well as endothelial cells and pericytes, suggesting shifts in both immune activation and within the vasculature. We validate our estimates of neuronal loss using neuropathological atrophy scores and show that neuronal loss in the cortex can be mainly attributed to excitatory neurons, and that increases in microglial and endothelial cell expression are highly correlated with neuronal loss. All our analyses identified a strong involvement of the cerebellum in the neurodegenerative process of FTLD-TDP. Altogether, our data provides a detailed landscape of gene expression alterations to help unravel relevant disease mechanisms in FTLD.
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Affiliation(s)
- Rahat Hasan
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Genetics and Genomic Sciences and Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Estelle and Daniel Maggin Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jack Humphrey
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Department of Genetics and Genomic Sciences and Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Estelle and Daniel Maggin Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Conceição Bettencourt
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
- Queen Square Brain Bank for Neurological Disorders, UCL Queen Square Institute of Neurology, London, UK
| | - Jia Newcombe
- NeuroResource, Department of Neuroinflammation, UCL Queen Square Institute of Neurology, London, UK
| | - Tammaryn Lashley
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
- Queen Square Brain Bank for Neurological Disorders, UCL Queen Square Institute of Neurology, London, UK
| | - Pietro Fratta
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Towfique Raj
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Department of Genetics and Genomic Sciences and Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Estelle and Daniel Maggin Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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Suresh P, Phasuk S, Liu IY. Modulation of microglia activation and Alzheimer's disease: CX3 chemokine ligand 1/CX3CR and P2X 7R signaling. Tzu Chi Med J 2021; 33:1-6. [PMID: 33505871 PMCID: PMC7821819 DOI: 10.4103/tcmj.tcmj_144_20] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 08/05/2020] [Accepted: 08/24/2020] [Indexed: 12/20/2022] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by cognitive deficits. Two hallmarks of AD that cause chronic inflammation and lead to neuronal dysfunction and damage are tau tangles and amyloid plaques. Microglial cells, the primary immune cells of the central nervous system, maintain a homeostatic active/inactive state via a bidirectional, dynamic communication with neurons. Several studies have revealed that dysregulated microglial activation leads to AD pathology. Therefore, we reviewed the relationship between AD and two important signaling complexes, CX3 chemokine ligand 1 (CX3CL1)/CX3CR1 and ATP/P2X7R, that play critical roles in the regulation of microglial activation. CX3CL1/CX3CR1 is one important signaling which controls the microglia function. Altering this pathway can have opposite effects on amyloid and tau pathology in AD. Another important molecule is P2X7R which involves in the activation of microglia. Over activation of P2X7R is evident in AD pathogenesis. In this review, we discuss influence of the two signaling pathways at different stages of AD pathology as well as the drug candidates that can modulate CX3CL1/CX3CR1 and ATP/P2X7R.
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Affiliation(s)
- Pavithra Suresh
- Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan
| | - Sarayut Phasuk
- Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan
| | - Ingrid Y Liu
- Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan
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Masuda N, Tsujinaka H, Hirai H, Yamashita M, Ueda T, Ogata N. Effects of concentration of amyloid β (Aβ) on viability of cultured retinal pigment epithelial cells. BMC Ophthalmol 2019; 19:70. [PMID: 30849957 PMCID: PMC6408759 DOI: 10.1186/s12886-019-1076-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 02/28/2019] [Indexed: 11/10/2022] Open
Abstract
Background Amyloid beta (Aβ) is a constituent of drusen that is a common sign of age-related macular degeneration (AMD). The purpose of this study was to investigate the effect of Aβ on human retinal pigment epithelial (RPE) cells in culture. Methods Cells from a human RPE cell line (ARPE-19) were exposed to 0 to 25 μM of Aβ 1–40 for 48 h, and the number of living cells was determined by WST-8 cleavage. Replicative DNA synthesis was measured by the incorporation of 5′-bromo-2′-deoxyuridine. The cell death pathway was investigated by the WST-8 cleavage assay after the addition of caspase-9 inhibitor, an anti-apoptotic factor. Real-time qRT-PCR was performed using Aβ-exposed cellular RNA to determine the level of vascular endothelial growth factor (VEGF)-A and pigment epithelium derived factor (PEDF). To determine the effect of receptor-for-advanced glycation end products (RAGE), the siRNA for RAGE was inserted into ARPE-19 treated with Aβ, and the levels of expression of VEGF-A and PEDF were determined. Results The number of living ARPE-19 cells was increased by exposure to 5 μM Aβ but was decreased by exposure to 25 μM of Aβ. Replicative DNA synthesis by ARPE-19 cells exposed to 25 μM of Aβ was significantly decreased indicating that 25 μM of Aβ inhibited cell proliferation. Real-time RT-PCR showed that the level of the mRNA of PEDF was increased by exposure to 5 μM Aβ, and the levels of the mRNAs of PEDF and VEGF-A were also increased by exposure to 25 μM Aβ. The addition of an inhibitor of caspase-9 blocked the decrease the number of ARPE-19 cells exposed to 25 μM Aβ. Exposure to si-RAGE attenuated the increase of VEGF-A and PEDF mRNA expression in ARPE-19 exposed to Aβ. Conclusions Exposure of ARPE-19 cells to low concentrations of Aβ increases the level of PEDF which then inhibits the apoptosis of ARPE-19 cells leading to RPE cell proliferation. Exposure to high concentrations of Aβ induces RPE cell death and enhances the expression of the mRNA of VEGF-A in RPE cells. The Aβ-RAGE pathway may lead to the expression VEGF-A and PEDF in RPE cells. These results suggest that Aβ is strongly related to the pathogenesis of choroidal neovascularization.
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Affiliation(s)
- Naonori Masuda
- Department of Ophthalmology, Nara Medical University, 840 Shijo-cho, Kashihara, 634-8522, Japan
| | - Hiroki Tsujinaka
- Department of Ophthalmology, Nara Medical University, 840 Shijo-cho, Kashihara, 634-8522, Japan
| | - Hiromasa Hirai
- Department of Ophthalmology, Nara Medical University, 840 Shijo-cho, Kashihara, 634-8522, Japan
| | - Mariko Yamashita
- Department of Ophthalmology, Nara Medical University, 840 Shijo-cho, Kashihara, 634-8522, Japan
| | - Tetsuo Ueda
- Department of Ophthalmology, Nara Medical University, 840 Shijo-cho, Kashihara, 634-8522, Japan
| | - Nahoko Ogata
- Department of Ophthalmology, Nara Medical University, 840 Shijo-cho, Kashihara, 634-8522, Japan.
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Luo P, Chu SF, Zhang Z, Xia CY, Chen NH. Fractalkine/CX3CR1 is involved in the cross-talk between neuron and glia in neurological diseases. Brain Res Bull 2018; 146:12-21. [PMID: 30496784 DOI: 10.1016/j.brainresbull.2018.11.017] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Revised: 11/17/2018] [Accepted: 11/23/2018] [Indexed: 01/27/2023]
Abstract
Fractalkine (CX3C chemokine ligand 1, CX3CL1) is an essential chemokine, for regulating adhesion and chemotaxis through binding to CX3CR1, which plays a critical role in the crosstalk between glial cells and neurons by direct or indirect ways in the central nervous system (CNS). Fractalkine/CX3CR1 axis regulates microglial activation and function, neuronal survival and synaptic function by controlling the release of inflammatory cytokines and synaptic plasticity in the course of the neurological disease. The multiple functions of fractalkine/CX3CR1 make it exert neuroprotective or neurotoxic effects, which determines the pathogenesis. However, the role of fractalkine/CX3CR1 in the CNS remains controversial. Whether it can be used as a therapeutic target for neurological diseases needs to be further investigated. In this review, we summarize the studies highlighting fractalkine/CX3CR1-mediated effects and discuss the potential neurotoxic and neuroprotective actions of fractalkine/CX3CR1 in brain injury for providing useful insights into the potential applications of fractalkine/CX3CR1 in neurological diseases.
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Affiliation(s)
- Piao Luo
- College of Pharmacy, Hunan University of Chinese Medicine, Changsha, Hunan 410208, People's Republic of China; State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, People's Republic of China
| | - Shi-Feng Chu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, People's Republic of China
| | - Zhao Zhang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, People's Republic of China
| | - Cong-Yuan Xia
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, People's Republic of China
| | - Nai-Hong Chen
- College of Pharmacy, Hunan University of Chinese Medicine, Changsha, Hunan 410208, People's Republic of China; State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, People's Republic of China.
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Bone marrow-derived cells in ocular neovascularization: contribution and mechanisms. Angiogenesis 2016; 19:107-18. [PMID: 26880135 PMCID: PMC4819501 DOI: 10.1007/s10456-016-9497-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Accepted: 02/02/2016] [Indexed: 01/16/2023]
Abstract
Ocular neovascularization often leads to severe vision loss. The role of bone marrow-derived cells (BMCs) in the development of ocular neovascularization, and its significance, is increasingly being recognized. In this review, we discuss their contribution and the potential mechanisms that mediate the effect of BMCs on the progression of ocular neovascularization. The sequence of events by which BMCs participate in ocular neovascularization can be roughly divided into four phases, i.e., mobilization, migration, adhesion and differentiation. This process is delicately regulated and liable to be affected by multiple factors. Cytokines such as vascular endothelial growth factor, granulocyte colony-stimulating factor and erythropoietin are involved in the mobilization of BMCs. Studies have also demonstrated a key role of cytokines such as stromal cell-derived factor-1, tumor necrosis factor-α, as well as vascular endothelial growth factor, in regulating the migration of BMCs. The adhesion of BMCs is mainly regulated by vascular cell adhesion molecule-1, intercellular adhesion molecule-1 and vascular endothelial cadherin. However, the mechanisms regulating the differentiation of BMCs are largely unknown at present. In addition, BMCs secrete cytokines that interact with the microenvironment of ocular neovascularization; their contribution to ocular neovascularization, especially choroidal neovascularization, can be aggravated by several risk factors. An extensive regulatory network is thought to modulate the role of BMCs in the development of ocular neovascularization. A comprehensive understanding of the involved mechanisms will help in the development of novel therapeutic strategies related to BMCs. In this review, we have limited the discussion to the recent progress in this field, especially the research conducted at our laboratory.
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Dworzak J, Renvoisé B, Habchi J, Yates EV, Combadière C, Knowles TP, Dobson CM, Blackstone C, Paulsen O, Murphy PM. Neuronal Cx3cr1 Deficiency Protects against Amyloid β-Induced Neurotoxicity. PLoS One 2015; 10:e0127730. [PMID: 26038823 PMCID: PMC4454597 DOI: 10.1371/journal.pone.0127730] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 04/20/2015] [Indexed: 01/06/2023] Open
Abstract
Cx3cr1, the receptor for the chemokine Cx3cl1 (fractalkine), has been implicated in the progression and severity of Alzheimer's disease-like pathology in mice, but the underlying mechanisms remain unclear. A complicating factor is that Cx3cr1 has been demonstrated in both neurons and microglia. Here, we have dissected the differences between neuronal and microglial Cx3cr1, specifically by comparing direct amyloid-β-induced toxicity in cultured, mature, microglia-depleted hippocampal neurons from wild-type and Cx3cr1-/- mice. Wild-type neurons expressed both Cx3cl1 and Cx3cr1 and released Cx3cl1 in response to amyloid-β. Knockout of neuronal Cx3cr1 abated amyloid-β-induced lactate dehydrogenase release. Furthermore, amyloid-β differentially induced depression of pre- and postsynaptic components of miniature excitatory postsynaptic currents, in a peptide conformation-dependent manner. Knockout of neuronal Cx3cr1 abated effects of both amyloid-β conformational states, which were differentiable by aggregation kinetics and peptide morphology. We obtained similar results after both acute and chronic treatment of cultured neurons with the Cx3cr1 antagonist F1. Thus, neuronal Cx3cr1 may impact Alzheimer's disease-like pathology by modulating conformational state-dependent amyloid-β-induced synaptotoxicity.
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Affiliation(s)
- Jenny Dworzak
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, United States of America
- Neuronal Oscillations Group, Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Benoît Renvoisé
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Johnny Habchi
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Emma V. Yates
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Christophe Combadière
- Centre d'Immunologie et des Maladies Infectieuses-Paris, Institut National de la Santé et de la Recherche Médicale, Paris, France
| | - Tuomas P. Knowles
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | | | - Craig Blackstone
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ole Paulsen
- Neuronal Oscillations Group, Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom
- * E-mail: (PMM); (OP)
| | - Philip M. Murphy
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail: (PMM); (OP)
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Qin W, Li Z, Luo S, Wu R, Pei Z, Huang R. Exogenous fractalkine enhances proliferation of endothelial cells, promotes migration of endothelial progenitor cells and improves neurological deficits in a rat model of ischemic stroke. Neurosci Lett 2014; 569:80-4. [PMID: 24704182 DOI: 10.1016/j.neulet.2014.03.052] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 03/21/2014] [Accepted: 03/22/2014] [Indexed: 11/18/2022]
Abstract
Fractalkine/CX3CL1, also called neurotactin, has been described as an angiogenic agent, and its expression is up-regulated in the penumbra after ischemia. This study was conducted to investigate the neovascular potential of fractalkine on rat models of transient middle cerebral artery occlusion (MCAO). Rats receiving intracerebroventricular injections of fractalkine were found to have improved neurological deficits, reduced cerebral infarct size and increased neuron survival for both doses (100ng and 1μg). Fractalkine exerted angiogenic effects that showed dose-dependent higher vascular densities in the peri-infarct area. Furthermore, exogenous fractalkine increased the proliferation of endothelial cells in a dose-dependent manner and enhanced the migration of endothelial progenitor cells at the higher dose (1μg) in ischemic penumbra. In conclusion, intracerebroventricular administration of fractalkine reduces ischemic damage by promoting neuroprotection and by inducing endothelial cell proliferation and endothelial progenitor cell migration, thereby enhancing neovascularization in the peri-infarct region.
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Affiliation(s)
- Wenjing Qin
- Department of Neurology, the Fifth Affiliated Hospital of Sun Yat-Sen University, Zhuhai 519000, China
| | - Zhendong Li
- Department of Neurology, the Fifth Affiliated Hospital of Sun Yat-Sen University, Zhuhai 519000, China.
| | - Shijian Luo
- Department of Neurology, the Fifth Affiliated Hospital of Sun Yat-Sen University, Zhuhai 519000, China
| | - Rui Wu
- Department of Neurology, the Fifth Affiliated Hospital of Sun Yat-Sen University, Zhuhai 519000, China
| | - Zhong Pei
- Department of Neurology, the First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China
| | - Ruxun Huang
- Department of Neurology, the First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China
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Schaumberg DA, Rose L, DeAngelis MM, Semba RD, Hageman GS, Chasman DI. Prospective study of common variants in CX3CR1 and risk of macular degeneration: pooled analysis from 5 long-term studies. JAMA Ophthalmol 2014; 132:84-95. [PMID: 24287500 DOI: 10.1001/jamaophthalmol.2013.5506] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
IMPORTANCE The CX3CR1 gene is implicated as a candidate gene for age-related macular degeneration (AMD) through several lines of evidence. There is uncertainty, however, as to whether common genetic variants in CX3CR1 alter risk of AMD, since prior studies have been inconsistent and mostly limited to evaluation of 2 nonsynonymous variants, T280M (rs3732378) and V249I (rs3732379). OBJECTIVE To determine if common variants in CX3CR1 predict future risk of AMD. DESIGN, SETTING, AND PARTICIPANTS Prospective nested case-control study within 5 large study populations with long-term follow-up. We measured genotypes for T280M, V249I, and 13 other common single-nucleotide polymorphisms (SNPs) of the CX3CR1 gene among people who developed AMD (n = 1110, including 369 with neovascular AMD) and 2532 age- and sex-matched controls. MAIN OUTCOMES AND MEASURES We determined the incidence rate ratios (RR) and 95% CIs for incidence of AMD for each variant and examined interactions with other AMD-associated variants and modifiable risk factors. RESULTS In additive genetic models, we identified nonsignificant associations with AMD for T280M (RR, 0.87; P = .07) and 3 other SNPs, rs2853707 (RR, 0.88; P = .07), rs12636547 (RR, 0.85; P = .10), and rs1877563 (RR, 0.84; P = .06), 1 of which, rs2853707, is positioned in the CX3CR1 promoter region and was associated with neovascular AMD (RR, 0.75; P = .03). We observed that a recessive model was a better fit to the data for some SNPs, with associations between rs11715522 and AMD (RR, 1.27; P = .03) and between rs2669845 (RR, 3.10; P = .04), rs2853707 (RR, 0.48; P = .050), and rs9868689 (RR, 0.31; P = .02) and neovascular AMD. Moreover, in exploratory analyses, we identified a number of possible interactions including between V249I and rs2669845 and dietary intake of ω-3 fatty acids (P = .004 and P = .009, respectively) for AMD; between rs2669845 and obesity (P = .03) for neovascular AMD; between T280M and complement component 3 (C3) R102G for AMD (P = .03); between rs2669845 and Y402H in complement factor H for AMD (P = .04); and between rs2669845, rs2853707, and V249I and C3 R102G for neovascular AMD (P = .008; .04; and .002, respectively). CONCLUSIONS AND RELEVANCE This study failed to identify significant associations between common CX3CR1 variants and AMD after considering the number of SNPs analyzed and multiple comparisons. However, we observed evidence consistent with recessive modes of association and that an effect of CX3CR1 variants may depend on other factors including dietary intake of ω-3 fatty acids, obesity, and genotypes at CFH Y402H and C3 R102G. If replicated in other populations, these findings would support a role for CX3CR1 in AMD but also suggest that its role may involve mechanisms that are independent of the T280M/V249I variations.
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Affiliation(s)
- Debra A Schaumberg
- Division of Preventive Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts2The Schepens Eye Research Institute, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts3Department
| | - Lynda Rose
- Division of Preventive Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | | | - Richard D Semba
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | | | - Daniel I Chasman
- Division of Preventive Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
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