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Brandli A, Vessey KA, Fletcher EL. The contribution of pattern recognition receptor signalling in the development of age related macular degeneration: the role of toll-like-receptors and the NLRP3-inflammasome. J Neuroinflammation 2024; 21:64. [PMID: 38443987 PMCID: PMC10913318 DOI: 10.1186/s12974-024-03055-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 02/26/2024] [Indexed: 03/07/2024] Open
Abstract
Age-related macular degeneration (AMD) is a leading cause of irreversible vision loss, characterised by the dysfunction and death of the photoreceptors and retinal pigment epithelium (RPE). Innate immune cell activation and accompanying para-inflammation have been suggested to contribute to the pathogenesis of AMD, although the exact mechanism(s) and signalling pathways remain elusive. Pattern recognition receptors (PRRs) are essential activators of the innate immune system and drivers of para-inflammation. Of these PRRs, the two most prominent are (1) Toll-like receptors (TLR) and (2) NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3)-inflammasome have been found to modulate the progression of AMD. Mutations in TLR2 have been found to be associated with an increased risk of developing AMD. In animal models of AMD, inhibition of TLR and NLRP3 has been shown to reduce RPE cell death, inflammation and angiogenesis signalling, offering potential novel treatments for advanced AMD. Here, we examine the evidence for PRRs, TLRs2/3/4, and NLRP3-inflammasome pathways in macular degeneration pathogenesis.
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Affiliation(s)
- Alice Brandli
- Department of Anatomy and Physiology, The University of Melbourne, Grattan St, Parkville, Victoria, 3010, Australia
- Roche Pharma Research and Early Development, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Kirstan A Vessey
- Department of Anatomy and Physiology, The University of Melbourne, Grattan St, Parkville, Victoria, 3010, Australia
| | - Erica L Fletcher
- Department of Anatomy and Physiology, The University of Melbourne, Grattan St, Parkville, Victoria, 3010, Australia.
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2
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Sauter MM, Noel H, Brandt CR. The RLR intrinsic antiviral system is expressed in neural retina and restricts lentiviral transduction of human Mueller cells. Exp Eye Res 2023; 236:109647. [PMID: 37689341 PMCID: PMC10834037 DOI: 10.1016/j.exer.2023.109647] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 08/24/2023] [Accepted: 09/06/2023] [Indexed: 09/11/2023]
Abstract
The retinoic acid-inducible gene I (RIG)-I-like receptor (RLR) family of RNA sensor proteins plays a key role in the innate immune response to viral nucleic acids, including viral gene delivery vectors, but little is known about the expression of RLR proteins in the retina. The purpose of this study was to characterize cell-specific expression patterns of RLR proteins in non-human primate (NHP) neural retina tissue and to examine if RLR pathway signaling restricts viral gene delivery transduction. Since RLR protein signaling converges at the mitochondrial antiviral signaling protein (MAVS), experiments were performed to determine if knockdown of MAVS affected FIVGFP transduction efficiency in the human Mueller cell line MIO-M1. Immunoblotting confirmed expression of RIG-I, melanoma differentiation-associated protein 5 (MDA5), laboratory of genetics and physiology 2 (LGP2), and MAVS proteins in MIO-M1 cells and NHP retina tissue. Double label immunofluorescence (IF) studies revealed RIG-I, LGP2, and MAVS were expressed in Mueller microglial cells in the NHP retina. In addition, LGP2 and MDA5 proteins were detected in cone and retinal ganglion cells (RGC). MDA5 was also present in a subset of calretinin positive amacrine cells, and in nuclei within the inner nuclear layer (INL). Knockdown of MAVS significantly increased the transduction efficiency of the lentiviral vector FIVGFP in MIO-M1 cells, compared to control cells. FIVGFP or AAVGFP challenge did not alter expression of the LGP2, MAVS, MDA5 or RIG-I genes in MIO-M1 cells or NHP retina tissue compared to media treated controls. Our data demonstrate that innate immune response proteins involved in viral RNA sensing, including MDA5, RIG-I, LGP2, and MAVS, are expressed in several cell types within the NHP neural retina. In addition, the MAVS protein restricts non-human lentiviral transduction efficiency in MIO-M1 cells.
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Affiliation(s)
- Monica M Sauter
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Hongyu Noel
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Curtis R Brandt
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, 53706, USA; Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, 53706, USA; McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, 53706, USA.
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3
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Kwilasz AJ, Clements MA, Larson TA, Harris KM, Litwiler ST, Woodall BJ, Todd LS, Schrama AEW, Mitten EH, Maier SF, Van Dam AM, Rice KC, Watkins LR. Involvement of TLR2-TLR4, NLRP3, and IL-17 in pain induced by a novel Sprague-Dawley rat model of experimental autoimmune encephalomyelitis. FRONTIERS IN PAIN RESEARCH 2022; 3:932530. [PMID: 36176709 PMCID: PMC9513159 DOI: 10.3389/fpain.2022.932530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 08/10/2022] [Indexed: 11/13/2022] Open
Abstract
Up to 92% of patients suffering from multiple sclerosis (MS) experience pain, most without adequate treatment, and many report pain long before motor symptoms associated with MS diagnosis. In the most commonly studied rodent model of MS, experimental autoimmune encephalomyelitis (EAE), motor impairments/disabilities caused by EAE can interfere with pain testing. In this study, we characterize a novel low-dose myelin-oligodendrocyte-glycoprotein (MOG)-induced Sprague-Dawley (SD) model of EAE-related pain in male rats, optimized to minimize motor impairments/disabilities. Adult male SD rats were treated with increasing doses of intradermal myelin-oligodendrocyte-glycoprotein (MOG1-125) (0, 4, 8, and 16 μg) in incomplete Freund's adjuvant (IFA) vehicle to induce mild EAE. Von Frey testing and motor assessments were conducted prior to EAE induction and then weekly thereafter to assess EAE-induced pain and motor impairment. Results from these studies demonstrated that doses of 8 and 16 μg MOG1-125 were sufficient to produce stable mechanical allodynia for up to 1 month in the absence of hindpaw motor impairments/disabilities. In the follow-up studies, these doses of MOG1-125, were administered to create allodynia in the absence of confounded motor impairments. Then, 2 weeks later, rats began daily subcutaneous injections of the Toll-like receptor 2 and 4 (TLR2-TLR4) antagonist (+)-naltrexone [(+)-NTX] or saline for an additional 13 days. We found that (+)-NTX also reverses EAE-induced mechanical allodynia in the MOG-induced SD rat model of EAE, supporting parallels between models, but now allowing a protracted timecourse to be examined completely free of motor confounds. Exploring further mechanisms, we demonstrated that both spinal NOD-like receptor protein 3 (NLRP3) and interleukin-17 (IL-17) are necessary for EAE-induced pain, as intrathecal injections of NLRP3 antagonist MCC950 and IL-17 neutralizing antibody both acutely reversed EAE-induced pain. Finally, we show that spinal glial immunoreactivity induced by EAE is reversed by (+)-NTX, and that spinal demyelination correlates with the severity of motor impairments/disabilities. These findings characterize an optimized MOG-induced SD rat model of EAE for the study of pain with minimal motor impairments/disabilities. Finally, these studies support the role of TLR2-TLR4 antagonists as a potential treatment for MS-related pain and other pain and inflammatory-related disorders.
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Affiliation(s)
- Andrew J. Kwilasz
- Department of Psychology and Neuroscience, University of Colorado, Boulder, CO, United States
- The Center for Neuroscience, University of Colorado, Boulder, CO, United States
| | - Madison A. Clements
- Department of Psychology and Neuroscience, University of Colorado, Boulder, CO, United States
- The Center for Neuroscience, University of Colorado, Boulder, CO, United States
| | - Tracey A. Larson
- Department of Psychology and Neuroscience, University of Colorado, Boulder, CO, United States
- The Center for Neuroscience, University of Colorado, Boulder, CO, United States
| | - Kevin M. Harris
- Department of Psychology and Neuroscience, University of Colorado, Boulder, CO, United States
- The Center for Neuroscience, University of Colorado, Boulder, CO, United States
| | - Scott T. Litwiler
- Department of Psychology and Neuroscience, University of Colorado, Boulder, CO, United States
- The Center for Neuroscience, University of Colorado, Boulder, CO, United States
| | - Brodie J. Woodall
- Department of Psychology and Neuroscience, University of Colorado, Boulder, CO, United States
- The Center for Neuroscience, University of Colorado, Boulder, CO, United States
| | - Laurel S. Todd
- Department of Psychology and Neuroscience, University of Colorado, Boulder, CO, United States
- The Center for Neuroscience, University of Colorado, Boulder, CO, United States
| | - Anouk E. W. Schrama
- Department of Psychology and Neuroscience, University of Colorado, Boulder, CO, United States
- The Center for Neuroscience, University of Colorado, Boulder, CO, United States
| | - Eric H. Mitten
- Department of Psychology and Neuroscience, University of Colorado, Boulder, CO, United States
- The Center for Neuroscience, University of Colorado, Boulder, CO, United States
| | - Steven F. Maier
- Department of Psychology and Neuroscience, University of Colorado, Boulder, CO, United States
- The Center for Neuroscience, University of Colorado, Boulder, CO, United States
| | - Anne-Marie Van Dam
- Department of Anatomy and Neuroscience, Amsterdam UMC, Vrije Universiteit, Amsterdam, Netherlands
| | - Kenner C. Rice
- Drug Design and Synthesis Section, National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, United States
| | - Linda R. Watkins
- Department of Psychology and Neuroscience, University of Colorado, Boulder, CO, United States
- The Center for Neuroscience, University of Colorado, Boulder, CO, United States
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4
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Bucher K, Rodriguez-Bocanegra E, Fischer MD. Benefits and Shortcomings of Laboratory Model Systems in the Development of Genetic Therapies. Klin Monbl Augenheilkd 2022; 239:263-269. [PMID: 35316853 DOI: 10.1055/a-1757-9879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Gene therapeutic approaches promise treatment or even a cure of diseases that were previously untreatable. Retinal gene therapies tested in clinical trials comprise a wide range of different strategies, including gene supplementation therapies, in vivo gene editing, modulation of splicing mechanisms, or the suppression of gene expression. To guarantee efficient transfer of genetic material into the respective target cells while avoiding major adverse effects, the development of genetic therapies requires appropriate in vitro model systems that allow tests of efficacy and safety of the gene therapeutic approach. In this review, we introduce various in vitro models of different levels of complexity used in the development of genetic therapies and discuss their respective benefits and shortcomings using the example of adeno-associated virus-based retinal gene therapy.
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Affiliation(s)
- Kirsten Bucher
- University Eye Hospital, University Hospital Tübingen Clinic of Ophthalmology, Tubingen, Germany.,Institute for Ophthalmic Research, University Hospital Tübingen Clinic of Ophthalmology, Tubingen, Germany
| | | | - M Dominik Fischer
- University Eye Hospital, University Hospital Tübingen Clinic of Ophthalmology, Tubingen, Germany.,Institute for Ophthalmic Research, University Hospital Tübingen Clinic of Ophthalmology, Tubingen, Germany.,Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom of Great Britain and Northern Ireland.,Department of Clinical Neurosciences, University of Oxford Nuffield Laboratory of Ophthalmology, Oxford, United Kingdom of Great Britain and Northern Ireland
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5
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Sanchez-Petidier M, Guerri C, Moreno-Manzano V. Toll-like receptors 2 and 4 differentially regulate the self-renewal and differentiation of spinal cord neural precursor cells. Stem Cell Res Ther 2022; 13:117. [PMID: 35314006 PMCID: PMC8935849 DOI: 10.1186/s13287-022-02798-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 03/07/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Toll-like receptors (TLRs) represent critical effectors in the host defense response against various pathogens; however, their known function during development has also highlighted a potential role in cell fate determination and neural differentiation. While glial cells and neural precursor cells (NPCs) of the spinal cord express both TLR2 and TLR4, their influence on self-renewal and cell differentiation remains incompletely described. METHODS TLR2, TLR4 knock-out and the wild type mice were employed for spinal cord tissue analysis and NPCs isolation at early post-natal stage. Sox2, FoxJ1 and Ki67 expression among others served to identify the undifferentiated and proliferative NPCs; GFAP, Olig2 and β-III-tubulin markers served to identify astrocytes, oligodendrocytes and neurons respectively after NPC spontaneous differentiation. Multiple comparisons were analyzed using one-way ANOVA, with appropriate corrections such as Tukey's post hoc tests used for comparisons. RESULTS We discovered that the deletion of TLR2 or TLR4 significantly reduced the number of Sox2-expressing NPCs in the neonatal mouse spinal cord. While TLR2-knockout NPCs displayed enhanced self-renewal, increased proliferation and apoptosis, and delayed neural differentiation, the absence of TLR4 promoted the neural differentiation of NPCs without affecting proliferation, producing long projecting neurons. TLR4 knock-out NPCs showed significantly higher expression of Neurogenin1, that would be involved in the activation of this neurogenic program by a ligand and microenvironment-independent mechanism. Interestingly, the absence of both TLR2 and TLR4, which induces also a significant reduction in the expression of TLR1, in NPCs impeded oligodendrocyte precursor cell maturation to a similar degree. CONCLUSIONS Our data suggest that Toll-like receptors are needed to maintain Sox2 positive neural progenitors in the spinal cord, however possess distinct regulatory roles in mouse neonatal spinal cord NPCs-while TLR2 and TLR4 play a similar role in oligodendrocytic differentiation, they differentially influence neural differentiation.
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Affiliation(s)
- Marina Sanchez-Petidier
- Neuronal and Tissue Regeneration Laboratory, Prince Felipe Research Institute, Valencia, Spain.,Neuropathology Laboratory, Prince Felipe Research Institute, Valencia, Spain
| | - Consuelo Guerri
- Neuropathology Laboratory, Prince Felipe Research Institute, Valencia, Spain.
| | - Victoria Moreno-Manzano
- Neuronal and Tissue Regeneration Laboratory, Prince Felipe Research Institute, Valencia, Spain.
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Sauter MM, Brandt CR. Knockdown of TRIM5α or TRIM11 increases lentiviral vector transduction efficiency of human Muller cells. Exp Eye Res 2021; 204:108436. [PMID: 33440192 DOI: 10.1016/j.exer.2021.108436] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/17/2020] [Accepted: 01/02/2021] [Indexed: 02/07/2023]
Abstract
The goal of this study was to determine the expression and distribution of the host restriction factors (RFs) TRIM5α and TRIM11 in non-human primate (NHP) neural retina tissue and the human Muller cell line MIO-M1. In addition, experiments were performed to determine the effect of TRIM5α and TRIM11 knockdown on FIVGFP transduction of MIO-M1 cells with the goal of devising strategies to increase the efficiency of lentiviral (LV) gene delivery. Immunofluorescence (IF) studies indicated that TRIM5α and TRIM11 were localized predominantly in nuclei within the outer nuclear layer (ONL) and inner nuclear layer (INL) of NHP retina tissue. Double label IF indicated that TRIM5α and TRIM11 were localized to some of the retinal Muller cell nuclei. MIO-M1 cells expressed TRIM5α predominantly in the nucleus and TRIM11 primarily in the cytosol. FIVGFP transduction efficiency was significantly increased, at 4 and 7 days post transduction, in TRIM5α and TRIM11 knockdown clones (KD) compared to WT MIO-M1 cells. In addition, pretreatment with the proteasome inhibitor MG132 increased the transduction efficiency of FIVGFP in WT MIO-M1 cells. The nuclear translocation of NF-κB (p65), at 72 h post FIVGFP transduction, was enhanced in TRIM5α and TRIM11 KD clones. The expression of TRIM5α and TRIM11 in macaque neural retina tissue and MIO-M1 cells indicate the presence of these RFs in NHP retina and human Muller cells. Our data indicate that even partial knockdown of TRIM5α or TRIM11, or a short proteasome inhibitor pretreatment, can increase the transduction efficiency of a LV vector.
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Affiliation(s)
- Monica M Sauter
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Curtis R Brandt
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, 53706, USA; Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, 53706, USA; McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, 53706, USA.
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7
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Bucher K, Rodríguez-Bocanegra E, Dauletbekov D, Fischer MD. Immune responses to retinal gene therapy using adeno-associated viral vectors - Implications for treatment success and safety. Prog Retin Eye Res 2020; 83:100915. [PMID: 33069860 DOI: 10.1016/j.preteyeres.2020.100915] [Citation(s) in RCA: 100] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 10/08/2020] [Accepted: 10/10/2020] [Indexed: 02/06/2023]
Abstract
Recombinant adeno-associated virus (AAV) is the leading vector for gene therapy in the retina. As non-pathogenic, non-integrating, replication deficient vector, the recombinant virus efficiently transduces all key retinal cell populations. Successful testing of AAV vectors in clinical trials of inherited retinal diseases led to the recent approval of voretigene neparvovec (Luxturna) for the treatment of RPE65 mutation-associated retinal dystrophies. However, studies applying AAV-mediated retinal gene therapy independently reported intraocular inflammation and/or loss of efficacy after initial functional improvements. Both observations might be explained by targeted removal of transduced cells via anti-viral defence mechanisms. AAV has been shown to activate innate pattern recognition receptors (PRRs) such as toll-like receptor (TLR)-2 and TLR-9 resulting in the release of inflammatory cytokines and type I interferons. The vector can also induce capsid-specific and transgene-specific T cell responses and neutralizing anti-AAV antibodies which both limit the therapeutic effect. However, the target organ of retinal gene therapy, the eye, is known as an immune-privileged site. It is characterized by suppression of inflammation and promotion of immune tolerance which might prevent AAV-induced immune responses. This review evaluates AAV-related immune responses, toxicity and inflammation in studies of retinal gene therapy, identifies influencing variables of these responses and discusses potential strategies to modulate immune reactions to AAV vectors to increase the safety and efficacy of ocular gene therapy.
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Affiliation(s)
- Kirsten Bucher
- University Eye Hospital, Centre for Ophthalmology, University Hospital Tübingen, Tübingen, Germany; Institute for Ophthalmic Research, Centre for Ophthalmology, University Hospital Tübingen, Tübingen, Germany
| | - Eduardo Rodríguez-Bocanegra
- University Eye Hospital, Centre for Ophthalmology, University Hospital Tübingen, Tübingen, Germany; Institute for Ophthalmic Research, Centre for Ophthalmology, University Hospital Tübingen, Tübingen, Germany
| | - Daniyar Dauletbekov
- University Eye Hospital, Centre for Ophthalmology, University Hospital Tübingen, Tübingen, Germany; Institute for Ophthalmic Research, Centre for Ophthalmology, University Hospital Tübingen, Tübingen, Germany
| | - M Dominik Fischer
- University Eye Hospital, Centre for Ophthalmology, University Hospital Tübingen, Tübingen, Germany; Institute for Ophthalmic Research, Centre for Ophthalmology, University Hospital Tübingen, Tübingen, Germany; Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK; Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
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Santiago AR, Madeira MH, Boia R, Aires ID, Rodrigues-Neves AC, Santos PF, Ambrósio AF. Keep an eye on adenosine: Its role in retinal inflammation. Pharmacol Ther 2020; 210:107513. [PMID: 32109489 DOI: 10.1016/j.pharmthera.2020.107513] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Adenosine is an endogenous purine nucleoside ubiquitously distributed throughout the body that interacts with G protein-coupled receptors, classified in four subtypes: A1R, A2AR, A2BR and A3R. Among the plethora of functions of adenosine, it has been increasingly recognized as a key mediator of the immune response. Neuroinflammation is a feature of chronic neurodegenerative diseases and contributes to the pathophysiology of several retinal degenerative diseases. Animal models of retinal diseases are helping to elucidate the regulatory roles of adenosine receptors in the development and progression of those diseases. Mounting evidence demonstrates that the adenosinergic system is altered in the retina during pathological conditions, compromising retinal physiology. This review focuses on the roles played by adenosine and the elements of the adenosinergic system (receptors, enzymes, transporters) in the neuroinflammatory processes occurring in the retina. An improved understanding of the molecular and cellular mechanisms of the signalling pathways mediated by adenosine underlying the onset and progression of retinal diseases will pave the way towards the identification of new therapeutic approaches.
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Affiliation(s)
- Ana Raquel Santiago
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, 3000-548 Coimbra, Portugal.
| | - Maria H Madeira
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, 3000-548 Coimbra, Portugal
| | - Raquel Boia
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Inês Dinis Aires
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Ana Catarina Rodrigues-Neves
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Paulo Fernando Santos
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal
| | - António Francisco Ambrósio
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, 3000-548 Coimbra, Portugal.
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Noailles A, Kutsyr O, Maneu V, Ortuño-Lizarán I, Campello L, de Juan E, Gómez-Vicente V, Cuenca N, Lax P. The Absence of Toll-Like Receptor 4 Mildly Affects the Structure and Function in the Adult Mouse Retina. Front Cell Neurosci 2019; 13:59. [PMID: 30873007 PMCID: PMC6401850 DOI: 10.3389/fncel.2019.00059] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 02/05/2019] [Indexed: 12/26/2022] Open
Abstract
The innate immune Toll-like receptor (TLR) family plays essential roles in cell proliferation, survival and function of the central nervous system. However, the way in which TLRs contribute to the development and maintenance of proper retinal structure and function remains uncertain. In this work, we assess the effect of genetic TLR4 deletion on the morphology and function of the retina in mice. Visual acuity and retinal responsiveness were evaluated in TLR4 knockout and wild type C57BL/6J control mice by means of an optomotor test and electroretinography, respectively, from P20 to P360. Retinal structure was also analyzed in both strains using confocal and electron microscopy. ERG data showed impaired retinal responsiveness in TLR4 KO mice, in comparison to wild type animals. The amplitudes of the scotopic a-waves were less pronounced in TLR4-deficient mice than in wild-type animals from P30 to P360, and TLR4 KO mice presented scotopic b-wave amplitudes smaller than those of age-matched control mice at all ages studied (P20 to P360). Visual acuity was also relatively poorer in TLR4 KO as compared to C57BL/6J mice from P20 to P360, with significant differences at P30 and P60. Immunohistochemical analysis of retinal vertical sections showed no differences between TLR4 KO and C57BL/6J mice, in terms of either photoreceptor number or photoreceptor structure. Horizontal cells also demonstrated no morphological differences between TLR4 KO and wild-type mice. However, TLR4 KO mice exhibited a lower density of bipolar cells (15% less at P30) and thus fewer bipolar cell dendrites than the wild type control mouse, even though both confocal and electron microscopy images showed no morphologic abnormalities in the synaptic contacts between the photoreceptors and second order neurons. Microglial cell density was significantly lower (26% less at P30) in TLR4 KO mice as compared to wild-type control mice. These results suggest that TLR4 deletion causes functional alterations in terms of visual response and acuity, probably through the loss of bipolar cells and microglia, but this receptor is not essential for the processing of visual information in the retina.
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Affiliation(s)
- Agustina Noailles
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Oksana Kutsyr
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Victoria Maneu
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain
| | - Isabel Ortuño-Lizarán
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Laura Campello
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Emilio de Juan
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Violeta Gómez-Vicente
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain
| | - Nicolás Cuenca
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain.,Institute Ramón Margalef, University of Alicante, Alicante, Spain
| | - Pedro Lax
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
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