1
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Ebrahimi M, Thompson P, Lauer AK, Sivaprasad S, Perry G. The retina-brain axis and diabetic retinopathy. Eur J Ophthalmol 2023; 33:2079-2095. [PMID: 37259525 DOI: 10.1177/11206721231172229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Diabetic retinopathy (DR) is a major contributor to permanent vision loss and blindness. Changes in retinal neurons, glia, and microvasculature have been the focus of intensive study in the quest to better understand DR. However, the impact of diabetes on the rest of the visual system has received less attention. There are reports of associations of changes in the visual system with preclinical and clinical manifestations of diabetes. Simultaneous investigation of the retina and the brain may shed light on the mechanisms underlying neurodegeneration in diabetics. Additionally, investigating the links between DR and other neurodegenerative disorders of the brain including Alzheimer's and Parkinson's disease may reveal shared mechanisms for neurodegeneration and potential therapy options.
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Affiliation(s)
- Moein Ebrahimi
- School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Network of Immunity in Infection, Malignancy, and Autoimmunity, Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Paul Thompson
- Imaging Genetics Center, Mark and Mary Stevens Institute for Neuroimaging and Informatics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Andreas K Lauer
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Sobha Sivaprasad
- National Institute of Health and Care Research Moorfields Biomedical Research Centre, Moorfields Eye Hospital, London, UK
| | - George Perry
- Department of Neuroscience, Developmental and Regenerative Biology, University of Texas and San Antonio, San Antonio, TX, USA
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2
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Yang R, Liu Q, Zhang M. The Past and Present Lives of the Intraocular Transmembrane Protein CD36. Cells 2022; 12:cells12010171. [PMID: 36611964 PMCID: PMC9818597 DOI: 10.3390/cells12010171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 12/19/2022] [Accepted: 12/27/2022] [Indexed: 01/03/2023] Open
Abstract
Cluster of differentiation 36 (CD36) belongs to the B2 receptors of the scavenger receptor class B family, which is comprised of single-chain secondary transmembrane glycoproteins. It is present in a variety of cell types, including monocytes, macrophages, microvascular endothelial cells, adipocytes, hepatocytes, platelets, skeletal muscle cells, kidney cells, cardiomyocytes, taste bud cells, and a variety of other cell types. CD36 can be localized on the cell surface, mitochondria, endoplasmic reticulum, and endosomes, playing a role in lipid accumulation, oxidative stress injury, apoptosis, and inflammatory signaling. Recent studies have found that CD36 is expressed in a variety of ocular cells, including retinal pigment epithelium (RPE), retinal microvascular endothelial cells, retinal ganglion cells (RGC), Müller cells, and photoreceptor cells, playing an important role in eye diseases, such as age-related macular degeneration (AMD), diabetic retinopathy (DR), and glaucoma. Therefore, a comprehensive understanding of CD36 function and downstream signaling pathways is of great significance for the prevention and treatment of eye diseases. This article reviews the molecular characteristics, distribution, and function of scavenger receptor CD36 and its role in ophthalmology in order to deepen the understanding of CD36 in eye diseases and provide new ideas for treatment strategies.
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Affiliation(s)
- Rucui Yang
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou 515041, China
- Department of Ophthalmology, Shantou University Medical College, Shantou University, Shantou 515041, China
| | - Qingping Liu
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou 515041, China
| | - Mingzhi Zhang
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou 515041, China
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3
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Simons ES, Smith MA, Dengler-Crish CM, Crish SD. Retinal ganglion cell loss and gliosis in the retinofugal projection following intravitreal exposure to amyloid-beta. Neurobiol Dis 2021; 147:105146. [PMID: 33122075 DOI: 10.1016/j.nbd.2020.105146] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 10/09/2020] [Accepted: 10/23/2020] [Indexed: 01/07/2023] Open
Abstract
Pathological accumulations of amyloid-beta (Aβ) peptide are found in retina early in Alzheimer's disease, yet its effects on retinal neuronal structure remain unknown. To investigate this, we injected fibrillized Aβ1-42 protein into the eye of adult C57BL/6 J mice and analyzed the retina, optic nerve (ON), and the superior colliculus (SC), the primary retinal target in mice. We found that retinal Aβ exposure stimulated microglial activation and retinal ganglion cell (RGC) loss as early as 1-week post-injection. Pathology was not limited to the retina, but propagated into other areas of the central nervous system. Microgliosis spread throughout the retinal projection (retina, ON, and SC), with multiplex protein quantitation demonstrating an increase in endogenously produced Aβ in the ON and SC corresponding to the injected retinas. Surprisingly, this pathology spread to the opposite side, with unilateral Aβ eye injections driving increased Aβ levels, neuroinflammation, and RGC death in the opposite, un-injected retinal projection. As Aβ-mediated microglial activation has been shown to propagate Aβ pathology, we also investigated the role of the Aβ-binding microglial scavenger receptor CD36 in this pathology. Transgenic mice lacking the CD36 receptor were resistant to Aβ-induced inflammation and RGC death up to 2 weeks following exposure. These results indicate that Aβ pathology drives regional neuropathology in the retina and does not remain isolated to the affected eye, but spreads throughout the nervous system. Further, CD36 may serve as a promising target to prevent Aβ-mediated inflammatory damage.
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Affiliation(s)
- E S Simons
- Northeast Ohio Medical University, Rootstown, OH 44272, United States; Kent State Biomedical Sciences Graduate Program, Kent, OH 44240, United States
| | - M A Smith
- Northeast Ohio Medical University, Rootstown, OH 44272, United States; Kent State Biomedical Sciences Graduate Program, Kent, OH 44240, United States; Akron Children's Hospital, Rebecca D. Considine Research Institute, Akron, OH 44302, United States
| | - C M Dengler-Crish
- Northeast Ohio Medical University, Rootstown, OH 44272, United States; Kent State Biomedical Sciences Graduate Program, Kent, OH 44240, United States
| | - S D Crish
- Northeast Ohio Medical University, Rootstown, OH 44272, United States; Kent State Biomedical Sciences Graduate Program, Kent, OH 44240, United States.
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4
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Alber J, Goldfarb D, Thompson LI, Arthur E, Hernandez K, Cheng D, DeBuc DC, Cordeiro F, Provetti-Cunha L, den Haan J, Van Stavern GP, Salloway SP, Sinoff S, Snyder PJ. Developing retinal biomarkers for the earliest stages of Alzheimer's disease: What we know, what we don't, and how to move forward. Alzheimers Dement 2020; 16:229-243. [PMID: 31914225 DOI: 10.1002/alz.12006] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 10/23/2019] [Accepted: 11/18/2019] [Indexed: 12/12/2022]
Abstract
The last decade has seen a substantial increase in research focused on the identification, development, and validation of diagnostic and prognostic retinal biomarkers for Alzheimer's disease (AD). Sensitive retinal biomarkers may be advantageous because they are cost and time efficient, non-invasive, and present a minimal degree of patient risk and a high degree of accessibility. Much of the work in this area thus far has focused on distinguishing between symptomatic AD and/or mild cognitive impairment (MCI) and cognitively normal older adults. Minimal work has been done on the detection of preclinical AD, the earliest stage of AD pathogenesis characterized by the accumulation of cerebral amyloid absent clinical symptoms of MCI or dementia. The following review examines retinal structural changes, proteinopathies, and vascular alterations that have been proposed as potential AD biomarkers, with a focus on studies examining the earliest stages of disease pathogenesis. In addition, we present recommendations for future research to move beyond the discovery phase and toward validation of AD risk biomarkers that could potentially be used as a first step in a multistep screening process for AD risk detection.
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Affiliation(s)
- Jessica Alber
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island, USA.,George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, Rhode Island, USA.,Department of Psychiatry and Human Behavior, Alpert Medical School of Brown University, Providence, Rhode Island, USA.,Butler Hospital Memory & Aging Program, Providence, Rhode Island, USA
| | | | - Louisa I Thompson
- Department of Psychiatry and Human Behavior, Alpert Medical School of Brown University, Providence, Rhode Island, USA.,Butler Hospital Memory & Aging Program, Providence, Rhode Island, USA
| | - Edmund Arthur
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island, USA.,George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, Rhode Island, USA.,Butler Hospital Memory & Aging Program, Providence, Rhode Island, USA
| | | | - Derrick Cheng
- Alpert Medical School of Brown University, Providence, Rhode Island, USA
| | - Delia Cabrera DeBuc
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami, Miami, Florida, USA
| | - Francesca Cordeiro
- Imperial College London, London, UK.,University College London, London, UK.,Western Eye Hospital, London, UK
| | - Leonardo Provetti-Cunha
- Federal University of Juiz de Fora Medical School, Juiz de Fora, Minas Gerais, Brazil.,Juiz de Fora Eye Hospital, Juiz de Fora, Minas Gerais, Brazil.,University of São Paulo Medical School, São Paulo, Brazil
| | - Jurre den Haan
- Alzheimer Center Amsterdam, Department of Neurology, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam UMC, Amsterdam, the Netherlands
| | - Gregory P Van Stavern
- Department of Ophthalmology and Visual Sciences, Washington University in St. Louis School of Medicine, St. Louis, Missouri, USA
| | - Stephen P Salloway
- Department of Psychiatry and Human Behavior, Alpert Medical School of Brown University, Providence, Rhode Island, USA.,Butler Hospital Memory & Aging Program, Providence, Rhode Island, USA.,Department of Neurology, Alpert Medical School of Brown University, Providence, Rhode Island, USA
| | | | - Peter J Snyder
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island, USA.,George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, Rhode Island, USA.,Department of Neurology and Department of Surgery (Ophthalmology), Alpert Medical School of Brown University, Providence, Rhode Island, USA
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5
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Gemenetzi M, Lotery AJ. Epigenetics in age-related macular degeneration: new discoveries and future perspectives. Cell Mol Life Sci 2020; 77:807-818. [PMID: 31897542 PMCID: PMC7058675 DOI: 10.1007/s00018-019-03421-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 12/04/2019] [Accepted: 12/10/2019] [Indexed: 12/13/2022]
Abstract
The study of epigenetics has explained some of the 'missing heritability' of age-related macular degeneration (AMD). The epigenome also provides a substantial contribution to the organisation of the functional retina. There is emerging evidence of specific epigenetic mechanisms associated with AMD. This 'AMD epigenome' may offer the chance to develop novel AMD treatments.
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Affiliation(s)
- M Gemenetzi
- NIHR Biomedical Research Centre At Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, 162 City Road, London, EC1V 2PD, UK
| | - A J Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University Hospital Southampton, University of Southampton, South Lab and Path Block, Mailpoint 806, Level D, Southampton, SO16 6YD, UK.
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6
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Shi Y, Wang Y, Wei H. Dantrolene : From Malignant Hyperthermia to Alzheimer's Disease. CNS & NEUROLOGICAL DISORDERS DRUG TARGETS 2019; 18:668-676. [PMID: 29921212 PMCID: PMC7754833 DOI: 10.2174/1871527317666180619162649] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Revised: 05/07/2018] [Accepted: 06/13/2018] [Indexed: 12/12/2022]
Abstract
Dantrolene, a ryanodine receptor antagonist, is primarily known as the only clinically acceptable and effective treatment for Malignant Hyperthermia (MH). Inhibition of Ryanodine Receptor (RyR) by dantrolene decreases the abnormal calcium release from the Sarcoplasmic Reticulum (SR) or Endoplasmic Reticulum (ER), where RyR is located. Recently, emerging researches on dissociated cells, brains slices, live animal models and patients have demonstrated that altered RyR expression and function can also play a vital role in the pathogenesis of Alzheimer's Disease (AD). Therefore, dantrolene is now widely studied as a novel treatment for AD, targeting the blockade of RyR channels or another alternative pathway, such as the inhibitory effects of NMDA glutamate receptors and the effects of ER-mitochondria connection. However, the therapeutic effects are not consistent. In this review, we focus on the relationship between the altered RyR expression and function and the pathogenesis of AD, and the potential application of dantrolene as a novel treatment for the disease.
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Affiliation(s)
- Yun Shi
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, 305 John Morgan Building, 3620 Hamilton Walk, Philadelphia, PA 19104, USA
- Department of Anesthesiology, Children’s Hospital of Fudan University, Shanghai, China
| | - Yong Wang
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, 305 John Morgan Building, 3620 Hamilton Walk, Philadelphia, PA 19104, USA
- Department of Anesthesiology, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou 510405, China
| | - Huafeng Wei
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, 305 John Morgan Building, 3620 Hamilton Walk, Philadelphia, PA 19104, USA
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7
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Sun J, Huang P, Liang J, Li J, Shen M, She X, Feng Y, Luo X, Liu T, Sun X. Cooperation of Rel family members in regulating Aβ 1-40-mediated pro-inflammatory cytokine secretion by retinal pigment epithelial cells. Cell Death Dis 2017; 8:e3115. [PMID: 29022897 PMCID: PMC5682668 DOI: 10.1038/cddis.2017.502] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 08/20/2017] [Accepted: 08/31/2017] [Indexed: 01/30/2023]
Abstract
Amyloid-beta (Aβ) is a hallmark component of age-related macular degeneration (AMD), which induces secretion of pro-inflammatory cytokines from retinal pigment epithelium (RPE). Previous studies have shown that p50/RelA (p65), a member of NF-κB family, is an essential pro-inflammatory transcription factor responding to Aβ1-40 stimulation, but few focused on the other two Rel transcription factor members – RelB and c-Rel – and their role in Aβ1-40-mediated inflammation. It was reported that RelA, RelB and c-Rel are also implicated in various NF-κB-mediated inflammatory diseases. Therefore, we infer that Aβ1-40-mediated inflammation targets not only the classical inflammation regulator, RelA, but also RelB and c-Rel. In this study, we demonstrate that intravitreally injected Aβ1-40 mice develop AMD-like pathologic changes, coupled with Rel protein (RelA, RelB and c-Rel) synthesis and nuclear translocation. To focus on the interaction mechanism of Rel proteins, we found that RelB and c-Rel formed a heterodimer with RelA in mice model. We also found that c-Rel silencing decreased the levels of Aβ1-40-dependent RelA expression, indicating that RelB and c-Rel may interact with RelA as coactivator and c-Rel is required to activate the expression of RelA. Moreover, Rel protein silencing decreased the expression of distinct pro-inflammatory cytokines. Together, we demonstrate that besides RelA, RelB and c-Rel can also be activated by Aβ1-40, all of which mediate pro-inflammatory cytokine transcription and RPE damage. Our findings imply that RPE-mediated inflammation under the stimulation of Aβ1-40 is multi-targeted and RelA, RelB and c-Rel proteins may be the new targets of anti-inflammatory agents.
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Affiliation(s)
- Junran Sun
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai 200080, China
| | - Peirong Huang
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai 200080, China
| | - Jian Liang
- Shanghai Key Laboratory of Fundus Diseases, Shanghai, China
| | - Jie Li
- Department of Ophthalmology, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Mengxi Shen
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai 200080, China
| | - Xiangjun She
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai 200080, China
| | - Yiji Feng
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai 200080, China
| | - Xueting Luo
- Shanghai Key Laboratory of Fundus Diseases, Shanghai, China
| | - Te Liu
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA.,Shanghai Geriatric Institute of Chinese Medicine, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Xiaodong Sun
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai 200080, China.,Shanghai Key Laboratory of Fundus Diseases, Shanghai, China
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8
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Lei C, Lin R, Wang J, Tao L, Fu X, Qiu Y, Lei B. Amelioration of amyloid β-induced retinal inflammatory responses by a LXR agonist TO901317 is associated with inhibition of the NF-κB signaling and NLRP3 inflammasome. Neuroscience 2017; 360:48-60. [DOI: 10.1016/j.neuroscience.2017.07.053] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 07/19/2017] [Accepted: 07/20/2017] [Indexed: 02/08/2023]
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9
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Aryanpour R, Pasbakhsh P, Zibara K, Namjoo Z, Beigi Boroujeni F, Shahbeigi S, Kashani IR, Beyer C, Zendehdel A. Progesterone therapy induces an M1 to M2 switch in microglia phenotype and suppresses NLRP3 inflammasome in a cuprizone-induced demyelination mouse model. Int Immunopharmacol 2017; 51:131-139. [PMID: 28830026 DOI: 10.1016/j.intimp.2017.08.007] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 05/14/2017] [Accepted: 08/09/2017] [Indexed: 12/14/2022]
Abstract
Demyelination of the central nervous system (CNS) has been associated to reactive microglia in neurodegenerative disorders, such as multiple sclerosis (MS). The M1 microglia phenotype plays a pro-inflammatory role while M2 is involved in anti-inflammatory processes in the brain. In this study, CPZ-induced demyelination mouse model was used to investigate the effect of progesterone (PRO) therapy on microglia activation and neuro-inflammation. Results showed that progesterone therapy (CPZ+PRO) decreased neurological behavioral deficits, as demonstrated by significantly decreased escape latencies, in comparison to CPZ mice. In addition, CPZ+PRO caused a significant reduction in the mRNA expression levels of M1-markers (iNOS, CD86, MHC-II and TNF-α) in the corpus callosum region, whereas the expression of M2-markers (Trem-2, CD206, Arg-1 and TGF-β) was significantly increased, in comparison to CPZ mice. Moreover, CPZ+PRO resulted in a significant decrease in the number of iNOS+ and Iba-1+/iNOS+ cells (M1), whereas TREM-2+ and Iba-1+/TREM-2+ cells (M2) significantly increased, in comparison to CPZ group. Furthermore, CPZ+PRO caused a significant decrease in mRNA and protein expression levels of NLRP3 and IL-18 (~2-fold), in comparison to the CPZ group. Finally, CPZ+PRO therapy was accompanied with reduced levels of demyelination, compared to CPZ, as confirmed by immunofluorescence to myelin basic protein (MBP) and Luxol Fast Blue (LFB) staining, as well as transmission electron microscopy (TEM) analysis. In summary, we reported for the first time that PRO therapy causes polarization of M2 microglia, attenuation of M1 phenotype, and suppression of NLRP3 inflammasome in a CPZ-induced demyelination model of MS.
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Affiliation(s)
- Roya Aryanpour
- Department of Anatomy, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Parichehr Pasbakhsh
- Department of Anatomy, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Kazem Zibara
- ER045, Laboratory of Stem Cells, DSST, Biology Department, Faculty of Sciences, Lebanese University, Beirut, Lebanon
| | - Zeinab Namjoo
- Department of Anatomy, Faculty of Medicine, Iran University of Medical Science, Tehran, Iran
| | - Fatemeh Beigi Boroujeni
- Department of Anatomy, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Saeed Shahbeigi
- Department of Anatomy, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Iraj Ragerdi Kashani
- Department of Anatomy, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
| | - Cordian Beyer
- Institute of Neuroanatomy, RWTH Aachen University, Aachen, Germany
| | - Adib Zendehdel
- Institute of Neuroanatomy, RWTH Aachen University, Aachen, Germany; Giulan Neuroscience Research Center, Department of Anatomical Sciences, Faculty of Medicine, Guilan University of Medical Sciences, Rasht, Iran
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10
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Romano GL, Platania CBM, Drago F, Salomone S, Ragusa M, Barbagallo C, Di Pietro C, Purrello M, Reibaldi M, Avitabile T, Longo A, Bucolo C. Retinal and Circulating miRNAs in Age-Related Macular Degeneration: An In vivo Animal and Human Study. Front Pharmacol 2017; 8:168. [PMID: 28424619 PMCID: PMC5371655 DOI: 10.3389/fphar.2017.00168] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Accepted: 03/14/2017] [Indexed: 01/05/2023] Open
Abstract
Age related macular degeneration (AMD) is the leading cause of blindness among people aged 50 and over. Retinal deposition of amyloid-β (Aβ) aggregates in AMD patients has suggested a potential link between AMD and Alzheimer's disease (AD). We have evaluated the differential retinal expression profile of miRNAs in a rat model of AMD elicited by Aβ. A serum profile of miRNAs in AMD patients has been also assessed using single TaqMan assay. Analysis of retina from rats intravitreally injected with Aβ revealed that miR-27a, miR-146a, and miR-155 were up-regulated in comparison to control rats. Seven miRNA (miR-9, miR-23a, miR-27a, miR-34a, miR-126, miR-146a, and miR-155) have been found to be dysregulated in serum of AMD patients in comparison to control group. Analysis of pathways has revealed that dysregulated miRNAs, both in the AMD animal model and in AMD patients, can target genes regulating pathways linked to neurodegeneration and inflammation, reinforcing the hypothesis that AMD is a protein misfolding disease similar to AD. In fact, miR-9, miR-23a, miR-27a, miR-34a, miR-146a, miR-155 have been found to be dysregulated both in AMD and AD. In conclusion, we suggest that miR-9, miR-23a, miR-27a, miR-34a, miR-146a, miR-155 represent potential biomarkers and new pharmacological targets for AMD.
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Affiliation(s)
- Giovanni L Romano
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of CataniaCatania, Italy
| | - Chiara B M Platania
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of CataniaCatania, Italy
| | - Filippo Drago
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of CataniaCatania, Italy
| | - Salvatore Salomone
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of CataniaCatania, Italy
| | - Marco Ragusa
- BioMolecular, Genome and Complex Systems BioMedicine Unit, Department of Biomedical and Biotechnological Sciences, Section of Biology and Genetics G. Sichel, University of CataniaCatania, Italy
| | - Cristina Barbagallo
- BioMolecular, Genome and Complex Systems BioMedicine Unit, Department of Biomedical and Biotechnological Sciences, Section of Biology and Genetics G. Sichel, University of CataniaCatania, Italy
| | - Cinzia Di Pietro
- BioMolecular, Genome and Complex Systems BioMedicine Unit, Department of Biomedical and Biotechnological Sciences, Section of Biology and Genetics G. Sichel, University of CataniaCatania, Italy
| | - Michele Purrello
- BioMolecular, Genome and Complex Systems BioMedicine Unit, Department of Biomedical and Biotechnological Sciences, Section of Biology and Genetics G. Sichel, University of CataniaCatania, Italy
| | - Michele Reibaldi
- Department of Ophthalmology, School of Medicine, University of CataniaCatania, Italy
| | - Teresio Avitabile
- Department of Ophthalmology, School of Medicine, University of CataniaCatania, Italy
| | - Antonio Longo
- Department of Ophthalmology, School of Medicine, University of CataniaCatania, Italy
| | - Claudio Bucolo
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of CataniaCatania, Italy
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11
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Lynn SA, Keeling E, Munday R, Gabha G, Griffiths H, Lotery AJ, Ratnayaka JA. The complexities underlying age-related macular degeneration: could amyloid beta play an important role? Neural Regen Res 2017; 12:538-548. [PMID: 28553324 PMCID: PMC5436342 DOI: 10.4103/1673-5374.205083] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Age-related macular degeneration (AMD) causes irreversible loss of central vision for which there is no effective treatment. Incipient pathology is thought to occur in the retina for many years before AMD manifests from midlife onwards to affect a large proportion of the elderly. Although genetic as well as non-genetic/environmental risks are recognized, its complex aetiology makes it difficult to identify susceptibility, or indeed what type of AMD develops or how quickly it progresses in different individuals. Here we summarize the literature describing how the Alzheimer's-linked amyloid beta (Aβ) group of misfolding proteins accumulate in the retina. The discovery of this key driver of Alzheimer's disease in the senescent retina was unexpected and surprising, enabling an altogether different perspective of AMD. We argue that Aβ fundamentally differs from other substances which accumulate in the ageing retina, and discuss our latest findings from a mouse model in which physiological amounts of Aβ were subretinally-injected to recapitulate salient features of early AMD within a short period. Our discoveries as well as those of others suggest the pattern of Aβ accumulation and pathology in donor aged/AMD tissues are closely reproduced in mice, including late-stage AMD phenotypes, which makes them highly attractive to study dynamic aspects of Aβ-mediated retinopathy. Furthermore, we discuss our findings revealing how Aβ behaves at single-cell resolution, and consider the long-term implications for neuroretinal function. We propose Aβ as a key element in switching to a diseased retinal phenotype, which is now being used as a biomarker for late-stage AMD.
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Affiliation(s)
- Savannah A Lynn
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Eloise Keeling
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Rosie Munday
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Gagandeep Gabha
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Helen Griffiths
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Andrew J Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom.,Eye Unit, University Southampton NHS Trust, Southampton, United Kingdom
| | - J Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
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Taylor-Walker G, Lynn SA, Keeling E, Munday R, Johnston DA, Page A, Scott JA, Goverdhan S, Lotery AJ, Ratnayaka JA. The Alzheimer's-related amyloid beta peptide is internalised by R28 neuroretinal cells and disrupts the microtubule associated protein 2 (MAP-2). Exp Eye Res 2016; 153:110-121. [PMID: 27751744 PMCID: PMC5131630 DOI: 10.1016/j.exer.2016.10.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 09/12/2016] [Accepted: 10/11/2016] [Indexed: 11/15/2022]
Abstract
Age-related Macular Degeneration (AMD) is a common, irreversible blinding condition that leads to the loss of central vision. AMD has a complex aetiology with both genetic as well as environmental risks factors, and share many similarities with Alzheimer's disease. Recent findings have contributed significantly to unravelling its genetic architecture that is yet to be matched by molecular insights. Studies are made more challenging by observations that aged and AMD retinas accumulate the highly pathogenic Alzheimer's-related Amyloid beta (Aβ) group of peptides, for which there appears to be no clear genetic basis. Analyses of human donor and animal eyes have identified retinal Aβ aggregates in retinal ganglion cells (RGC), the inner nuclear layer, photoreceptors as well as the retinal pigment epithelium. Aβ is also a major drusen constituent; found correlated with elevated drusen-load and age, with a propensity to aggregate in retinas of advanced AMD. Despite this evidence, how such a potent driver of neurodegeneration might impair the neuroretina remains incompletely understood, and studies into this important aspect of retinopathy remains limited. In order to address this we exploited R28 rat retinal cells which due to its heterogeneous nature, offers diverse neuroretinal cell-types in which to study the molecular pathology of Aβ. R28 cells are also unaffected by problems associated with the commonly used RGC-5 immortalised cell-line, thus providing a well-established model in which to study dynamic Aβ effects at single-cell resolution. Our findings show that R28 cells express key neuronal markers calbindin, protein kinase C and the microtubule associated protein-2 (MAP-2) by confocal immunofluorescence which has not been shown before, but also calretinin which has not been reported previously. For the first time, we reveal that retinal neurons rapidly internalised Aβ1-42, the most cytotoxic and aggregate-prone amongst the Aβ family. Furthermore, exposure to physiological amounts of Aβ1-42 for 24 h correlated with impairment to neuronal MAP-2, a cytoskeletal protein which regulates microtubule dynamics in axons and dendrites. Disruption to MAP-2 was transient, and had recovered by 48 h, although internalised Aβ persisted as discrete puncta for as long as 72 h. To assess whether Aβ could realistically localise to living retinas to mediate such effects, we subretinally injected nanomolar levels of oligomeric Aβ1-42 into wildtype mice. Confocal microscopy revealed the presence of focal Aβ deposits in RGC, the inner nuclear and the outer plexiform layers 8 days later, recapitulating naturally-occurring patterns of Aβ aggregation in aged retinas. Our novel findings describe how retinal neurons internalise Aβ to transiently impair MAP-2 in a hitherto unreported manner. MAP-2 dysfunction is reported in AMD retinas, and is thought to be involved in remodelling and plasticity of post-mitotic neurons. Our insights suggest a molecular pathway by which this could occur in the senescent eye leading to complex diseases such as AMD. Molecular basis of complex retinopathies such as AMD is incompletely understood. The Alzheimer's-related Aβ peptides are rapidly internalised by retinal neurons. Internalised Aβ is retained within neurons and transiently impairs MAP-2. Subretinally injected Aβ mimics its naturally-occurring distribution in aged retinas.
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Affiliation(s)
- George Taylor-Walker
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, SGH, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Savannah A Lynn
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, SGH, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Eloise Keeling
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, SGH, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Rosie Munday
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, SGH, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - David A Johnston
- Biomedical Imaging Unit, University of Southampton, SGH, MP12, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Anton Page
- Biomedical Imaging Unit, University of Southampton, SGH, MP12, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Jennifer A Scott
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, SGH, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Srini Goverdhan
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, SGH, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Andrew J Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, SGH, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom; Eye Unit, University Southampton NHS Trust, Southampton, SO16 6YD, United Kingdom
| | - J Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, SGH, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom.
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Snyder PJ, Johnson LN, Lim YY, Santos CY, Alber J, Maruff P, Fernández B. Nonvascular retinal imaging markers of preclinical Alzheimer's disease. ALZHEIMER'S & DEMENTIA: DIAGNOSIS, ASSESSMENT & DISEASE MONITORING 2016; 4:169-178. [PMID: 27830174 PMCID: PMC5078641 DOI: 10.1016/j.dadm.2016.09.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Introduction In patients with Alzheimer's disease (AD) and mild cognitive impairment, structural changes in the retina (i.e., reduced thicknesses of the ganglion cell and retinal nerve fiber layers and inclusion bodies that appear to contain beta-amyloid protein [Ab]) have been previously reported. We sought to explore whether anatomic retinal changes are detectable in the preclinical stage of AD. Methods A cross-sectional study (as part of an ongoing longitudinal cohort study) involving 63 cognitively normal adults, all of whom have a parent with AD and subjective memory complaints. We compared neocortical amyloid aggregation (florbetapir PET imaging) to retinal spectral domain optical coherence tomography (SD-OCT) markers of possible disease burden. Retinal biomarkers, including the number and surface area of retinal inclusion bodies and the thickness of retinal neuronal layers, were compared across groups with high vs. low neocortical beta-amyloid load. Results The surface area of inclusion bodies increased as a function of cortical amyloid burden. Additionally, there was a trend toward a selective volume increase in the inner plexiform layer (IPL; a layer rich in cholinergic activity) of the retina in Aβ+ relative to Aβ− participants, and IPL volume was correlated with the surface area of retinal inclusion bodies. Discussion These initial results suggest that retinal imaging may be a potential cost-effective and noninvasive technique that can be used to identify those at-risk for AD. Layer-specific changes in the IPL and their association with surface area of inclusion bodies are discussed as a possible reflection of early inflammatory processes associated with cholinergic disruption and concurrent Ab accumulation in the neocortex.
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Affiliation(s)
- Peter J Snyder
- Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI, USA; Lifespan Clinical Research Center, Rhode Island Hospital, Providence, RI, USA
| | - Lenworth N Johnson
- Lifespan Clinical Research Center, Rhode Island Hospital, Providence, RI, USA; Neuro-Ophthalmology Unit, Department of Ophthalmology, Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Yen Ying Lim
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia
| | - Cláudia Y Santos
- Lifespan Clinical Research Center, Rhode Island Hospital, Providence, RI, USA; Interdisciplinary Neuroscience Program, University of Rhode Island, Kingston, RI, USA
| | - Jessica Alber
- Lifespan Clinical Research Center, Rhode Island Hospital, Providence, RI, USA; Department of Psychiatry and Human Behavior, Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Paul Maruff
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia; Cogstate Ltd., Melbourne, Victoria, Australia
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Crespo-Garcia S, Reichhart N, Hernandez-Matas C, Zabulis X, Kociok N, Brockmann C, Joussen AM, Strauss O. In vivo analysis of the time and spatial activation pattern of microglia in the retina following laser-induced choroidal neovascularization. Exp Eye Res 2015. [PMID: 26213305 DOI: 10.1016/j.exer.2015.07.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Microglia play a major role in retinal neovascularization and degeneration and are thus potential targets for therapeutic intervention. In vivo assessment of microglia behavior in disease models can provide important information to understand patho-mechanisms and develop therapeutic strategies. Although scanning laser ophthalmoscope (SLO) permits the monitoring of microglia in transgenic mice with microglia-specific GFP expression, there are fundamental limitations in reliable identification and quantification of activated cells. Therefore, we aimed to improve the SLO-based analysis of microglia using enhanced image processing with subsequent testing in laser-induced neovascularization (CNV). CNV was induced by argon laser in MacGreen mice. Microglia was visualized in vivo by SLO in the fundus auto-fluorescence (FAF) mode and verified ex vivo using retinal preparations. Three image processing algorithms based on different analysis of sequences of images were tested. The amount of recorded frames was limiting the effectiveness of the different algorithms. Best results from short recordings were obtained with a pixel averaging algorithm, further used to quantify spatial and temporal distribution of activated microglia in CNV. Morphologically, different microglia populations were detected in the inner and outer retinal layers. In CNV, the peak of microglia activation occurred in the inner layer at day 4 after laser, lacking an acute reaction. Besides, the spatial distribution of the activation changed by the time over the inner retina. No significant time and spatial changes were observed in the outer layer. An increase in laser power did not increase number of activated microglia. The SLO, in conjunction with enhanced image processing, is suitable for in vivo quantification of microglia activation. This surprisingly revealed that laser damage at the outer retina led to more reactive microglia in the inner retina, shedding light upon a new perspective to approach the immune response in the retina in vivo.
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Affiliation(s)
- Sergio Crespo-Garcia
- Department of Ophthalmology, Charité University Medicine Berlin, Berlin, Germany
| | - Nadine Reichhart
- Department of Ophthalmology, Charité University Medicine Berlin, Berlin, Germany
| | - Carlos Hernandez-Matas
- Institute of Computer Science, Foundation for Research and Technology - Hellas, Heraklion, Greece; Computer Science Department, University of Crete, Heraklion, Greece
| | - Xenophon Zabulis
- Institute of Computer Science, Foundation for Research and Technology - Hellas, Heraklion, Greece
| | - Norbert Kociok
- Department of Ophthalmology, Charité University Medicine Berlin, Berlin, Germany
| | - Claudia Brockmann
- Department of Ophthalmology, Charité University Medicine Berlin, Berlin, Germany
| | - Antonia M Joussen
- Department of Ophthalmology, Charité University Medicine Berlin, Berlin, Germany
| | - Olaf Strauss
- Department of Ophthalmology, Charité University Medicine Berlin, Berlin, Germany.
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Horstmann L, Schmid H, Heinen AP, Kurschus FC, Dick HB, Joachim SC. Inflammatory demyelination induces glia alterations and ganglion cell loss in the retina of an experimental autoimmune encephalomyelitis model. J Neuroinflammation 2013; 10:120. [PMID: 24090415 PMCID: PMC3851328 DOI: 10.1186/1742-2094-10-120] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 09/24/2013] [Indexed: 12/29/2022] Open
Abstract
Background Multiple sclerosis (MS) is often accompanied by optic nerve inflammation. And some patients experience permanent vision loss. We examined if the grade of optic nerve infiltration and demyelination affects the severity of clinical signs in an experimental autoimmune encephalomyelitis (EAE) model. The loss of retinal ganglion cells (RGC) and alterations in glia activity were also investigated. Methods C57BL/6 mice were immunized with peptide MOG35-55 in complete Freund’s adjuvant (CFA) and controls received PBS in CFA. Then 23 days post immunization eyes were prepared for flatmounts and stained with Nissl to evaluated neuronal density. Clinical EAE symptoms as well as cell infiltration and demyelination in the optic nerve were examined. Retinal sections were stained with hematoxylin and eosin and silver stain. Immunohistochemistry was used to label RGCs (Brn-3a), apoptotic cells (caspase 3), macroglia (glial fibrillary acidic protein (GFAP)), microglia (Iba1), macrophages (F 4/80) and interleukin-6 (IL-6) secretion. Results EAE symptoms started at day 8 and peaked at day 15. Cell infiltrations (P = 0.0047) and demyelination (P = 0.0018) of EAE nerves correlated with the clinical score (r > 0.8). EAE led to a significant loss of RGCs (P< 0.0001). Significantly more caspase 3+ cells were noted in these animals (P = 0.0222). They showed an increased expression of GFAP (P< 0.0002) and a higher number of microglial cells (P< 0.0001). Also more macrophages and IL-6 secretion were observed in EAE mice. Conclusions MOG immunization leads to optic neuritis and RGC loss. EAE severity is related to the severity of optic nerve inflammation and demyelination. EAE not only affects activation of apoptotic signals, but also causes a glial response in the retina.
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Affiliation(s)
- Lioba Horstmann
- Experimental Eye Research Institute, Ruhr University Eye Hospital, In der Schornau 23-25, 44892 Bochum, Germany.
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Catchpole I, Germaschewski V, Hoh Kam J, Lundh von Leithner P, Ford S, Gough G, Adamson P, Overend P, Hilpert J, López FJ, Ng YSE, Coffey P, Jeffery G. Systemic administration of Abeta mAb reduces retinal deposition of Abeta and activated complement C3 in age-related macular degeneration mouse model. PLoS One 2013; 8:e65518. [PMID: 23799019 PMCID: PMC3682980 DOI: 10.1371/journal.pone.0065518] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Accepted: 05/01/2013] [Indexed: 11/21/2022] Open
Abstract
Age-related macular degeneration (AMD) is a leading cause of legal blindness in the Western world. There are effective treatments for the vascular complications of neo-vascular AMD, but no effective therapies are available for the dry/atrophic form of the disease. A previously described transgenic CFH-gene deficient mouse model, (cfh−/−), shows hallmarks of early AMD. The ocular phenotype has been further analysed to demonstrate amyloid beta (Aβ) rich basement membrane deposits associated with activated complement C3. Cfh−/− mice were treated systemically in both prophylactic and therapeutic regimes with an anti-Aβ monoclonal antibody (mAb), 6F6, to determine the effect on the cfh−/− retinal phenotype. Prophylactic treatment with 6F6 demonstrated a dose dependent reduction in the accumulation of both Aβ and activated C3 deposition. A similar reduction in the retinal endpoints could be seen after therapeutic treatment. Serum Aβ levels after systemic administration of 6F6 show accumulation of Aβ in the periphery suggestive of a peripheral sink mechanism. In summary, anti-Aβ mAb treatment can partially prevent or reverse ocular phenotypes of the cfh−/− mouse. The data support this therapeutic approach in humans potentially modulating two key elements in the pathogenesis of AMD – Aβ and activated, complement C3.
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Affiliation(s)
- Ian Catchpole
- Topical BioPharm Discovery Research and Development Unit, King of Prussia, Philadelphia, Pennsylvania, United States of America.
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Liu RT, Gao J, Cao S, Sandhu N, Cui JZ, Chou CL, Fang E, Matsubara JA. Inflammatory mediators induced by amyloid-beta in the retina and RPE in vivo: implications for inflammasome activation in age-related macular degeneration. Invest Ophthalmol Vis Sci 2013; 54:2225-37. [PMID: 23462752 DOI: 10.1167/iovs.12-10849] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
PURPOSE Drusen are hallmarks of age-related macular degeneration (AMD). Amyloid-beta 1-40 (Aβ 1-40), a constituent of drusen, is known to stimulate inflammatory pathways in RPE; however, its effect in vivo is not known. The purpose of this study was to examine the effect of Aβ 1-40 on cytokine expression and inflammasome activation relevant to AMD in an animal model. METHODS Wild-type rats received intravitreal injections of Aβ 1-40, and eyes were taken at days 1, 4, 14, and 49 postinjection. The RPE, neuroretina, and vitreous were analyzed for cytokine expression, inflammasome activation, and microglial response via RT-PCR, immunohistochemistry, and suspension array assay. Retinal cell loss was assessed via apoptotic markers and retinal thickness. RESULTS Aβ 1-40 stimulated upregulation of IL-6, TNF-α, IL-1β, IL-18, caspase-1, NLRP3, and XAF1 genes in the RPE/choroid and the neuroretina. Increased IL-1β and IL-6 immunoreactivity was found in retinal sections, and elevated levels of IL-1β and IL-18 were found in the vitreous of Aβ-injected eyes. Aβ 1-40 induced a moderate increase in CD11b/c-reactive cells on day 1 postinjection only. No evidence of the proapoptotic XAF1 protein, p53, TUNEL immunoreactivity, or retinal thinning was observed. CONCLUSIONS These results confirm earlier in vitro work and support the proinflammatory role of drusen component Aβ 1-40 in the RPE and retina. Inflammasome activation may be responsible for this effect in vivo. This model is useful for understanding cellular triggers of inflammasome activation and proposed early inflammatory events in the outer retina associated with the etiology of AMD.
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Affiliation(s)
- Ruozhou Tom Liu
- Department of Ophthalmology and Visual Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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Joachim SC, Gramlich OW, Laspas P, Schmid H, Beck S, von Pein HD, Dick HB, Pfeiffer N, Grus FH. Retinal ganglion cell loss is accompanied by antibody depositions and increased levels of microglia after immunization with retinal antigens. PLoS One 2012; 7:e40616. [PMID: 22848388 PMCID: PMC3406064 DOI: 10.1371/journal.pone.0040616] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2012] [Accepted: 06/11/2012] [Indexed: 12/25/2022] Open
Abstract
Background Antibodies against retinal and optic nerve antigens are detectable in glaucoma patients. Recent studies using a model of experimental autoimmune glaucoma demonstrated that immunization with certain ocular antigens causes an immun-mediated retinal ganglion cell loss in rats. Methodology/Principal Findings Rats immunized with a retinal ganglion cell layer homogenate (RGA) had a reduced retinal ganglion cell density on retinal flatmounts (p = 0.007) and a lower number of Brn3+retinal ganglion cells (p = 0.0001) after six weeks. The autoreactive antibody development against retina and optic nerve was examined throughout the study. The levels of autoreactive antibodies continuously increased up to 6 weeks (retina: p = 0.004; optic nerve: p = 0.000003). Additionally, antibody deposits were detected in the retina (p = 0.02). After 6 weeks a reactive gliosis (GFAP density: RGA: 174.7±41.9; CO: 137.6±36.8, p = 0.0006; %GFAP+ area: RGA: 8.5±3.4; CO: 5.9±3.6, p = 0.006) as well as elevated level of Iba1+ microglia cells (p = 0.003) was observed in retinas of RGA animals. Conclusions/Significance Our findings suggest that these antibodies play a substantial role in mechanisms leading to retinal ganglion cell death. This seems to lead to glia cell activation as well as the invasion of microglia, which might be associated with debris clearance.
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Affiliation(s)
- Stephanie C Joachim
- Experimental Eye Research Institute, Ruhr University Eye Hospital, Bochum, Germany.
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Kur J, Newman EA, Chan-Ling T. Cellular and physiological mechanisms underlying blood flow regulation in the retina and choroid in health and disease. Prog Retin Eye Res 2012; 31:377-406. [PMID: 22580107 DOI: 10.1016/j.preteyeres.2012.04.004] [Citation(s) in RCA: 450] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 04/17/2012] [Accepted: 04/22/2012] [Indexed: 02/06/2023]
Abstract
We review the cellular and physiological mechanisms responsible for the regulation of blood flow in the retina and choroid in health and disease. Due to the intrinsic light sensitivity of the retina and the direct visual accessibility of fundus blood vessels, the eye offers unique opportunities for the non-invasive investigation of mechanisms of blood flow regulation. The ability of the retinal vasculature to regulate its blood flow is contrasted with the far more restricted ability of the choroidal circulation to regulate its blood flow by virtue of the absence of glial cells, the markedly reduced pericyte ensheathment of the choroidal vasculature, and the lack of intermediate filaments in choroidal pericytes. We review the cellular and molecular components of the neurovascular unit in the retina and choroid, techniques for monitoring retinal and choroidal blood flow, responses of the retinal and choroidal circulation to light stimulation, the role of capillaries, astrocytes and pericytes in regulating blood flow, putative signaling mechanisms mediating neurovascular coupling in the retina, and changes that occur in the retinal and choroidal circulation during diabetic retinopathy, age-related macular degeneration, glaucoma, and Alzheimer's disease. We close by discussing issues that remain to be explored.
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Affiliation(s)
- Joanna Kur
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
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