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Torres-Rico M, García-Calvo V, Gironda-Martínez A, Pascual-Guerra J, García AG, Maneu V. Targeting calciumopathy for neuroprotection: focus on calcium channels Cav1, Orai1 and P2X7. Cell Calcium 2024; 123:102928. [PMID: 39003871 DOI: 10.1016/j.ceca.2024.102928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Revised: 07/02/2024] [Accepted: 07/05/2024] [Indexed: 07/16/2024]
Abstract
As the uncontrolled entry of calcium ions (Ca2+) through plasmalemmal calcium channels is a cell death trigger, the conjecture is here raised that mitigating such an excess of Ca2+ entry should rescue from death the vulnerable neurons in neurodegenerative diseases (NDDs). However, this supposition has failed in some clinical trials (CTs). Thus, a recent CT tested whether isradipine, a blocker of the Cav1 subtype of voltage-operated calcium channels (VOCCs), exerted a benefit in patients with Parkinson's disease (PD); however, outcomes were negative. This is one more of the hundreds of CTs done under the principle of one-drug-one-target, that have failed in Alzheimer's disease (AD) and other NDDs during the last three decades. As there are myriad calcium channels to let Ca2+ ions gain the cell cytosol, it seems reasonable to predict that blockade of Ca2+ entry through a single channel may not be capable of preventing the Ca2+ flood of cells by the uncontrolled Ca2+ entry. Furthermore, as Ca2+ signaling is involved in the regulation of myriad functions in different cell types, it seems also reasonable to guess that a therapy should be more efficient by targeting different cells with various drugs. Here, we propose to mitigate Ca2+ entry by the simultaneous partial blockade of three quite different subtypes of plasmalemmal calcium channels that is, the Cav1 subtype of VOCCs, the Orai1 store-operated calcium channel (SOCC), and the purinergic P2X7 calcium channel. All three channels are expressed in both microglia and neurons. Thus, by targeting the three channels with a combination of three drug blockers we expect favorable changes in some of the pathogenic features of NDDs, namely (i) to mitigate Ca2+ entry into microglia; (ii) to decrease the Ca2+-dependent microglia activation; (iii) to decrease the sustained neuroinflammation; (iv) to decrease the uncontrolled Ca2+ entry into neurons; (v) to rescue vulnerable neurons from death; and (vi) to delay disease progression. In this review we discuss the arguments underlying our triad hypothesis in the sense that the combination of three repositioned medicines targeting Cav1, Orai1, and P2X7 calcium channels could boost neuroprotection and delay the progression of AD and other NDDs.
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Affiliation(s)
| | | | - Adrián Gironda-Martínez
- Instituto Fundación Teófilo Hernando, Madrid, Spain; Departamento de Farmacología y Terapéutica, Universidad Autónoma de Madrid, Madrid, Spain
| | | | - Antonio G García
- Instituto Fundación Teófilo Hernando, Madrid, Spain; Departamento de Farmacología y Terapéutica, Universidad Autónoma de Madrid, Madrid, Spain; Facultad de Medicina, Instituto de Investigación Sanitaria del Hospital Universitario La Princesa, Universidad Autónoma de Madrid, Madrid, Spain.
| | - Victoria Maneu
- Departamento de Óptica, Farmacología y Anatomía, Universidad de Alicante, Alicante, Spain.
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Noori H, Majidpour M, Sabeti Akbar-Abad M, Saravani R. Association of polymorphisms within P2RX4 with type 2 diabetes mellitus: a preliminary case-control study. NUCLEOSIDES, NUCLEOTIDES & NUCLEIC ACIDS 2024:1-11. [PMID: 38954847 DOI: 10.1080/15257770.2024.2373300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 06/20/2024] [Indexed: 07/04/2024]
Abstract
OBJECTIVE Type 2 diabetes mellitus (T2DM) is a complex heterogenic metabolic with a wide range of etiology. Purinergic receptors have pivotal roles in different processes and are hypothesized to have roles in the pathogenesis of T2DM. MATERIALS AND METHODS Three hundred subjects affected by T2DM and 300 healthy subjects were genotyped by amplification refractory mutation system polymerase chain reaction (ARMS-PCR). SPSS V16.0 was recruited for statistical analysis. RESULTS The findings showed that the G allele of rs25644A > G increases the risk of T2DM in our population statistically (OR = 1.51, 95% CI = 1.14-1.99, p = 0.003). This allele in some genotype models, including the dominant model, caused an increase in the risk of T2DM. The interaction of genotypes between studied variants in the P2XR4 gene increased the risk of T2DM. Haplotype analysis showed that Ars1169727/Grs25644 haplotype caused an increase in the risk of T2DM. CONCLUSIONS The findings suggest that rs25644A > G plays a role in our population's increased risk of T2DM.
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Affiliation(s)
- Homa Noori
- Department of Biology, Payame Noor University of Mashhad, Iran
| | - Mahdi Majidpour
- Clinical Immunology Research Center, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Mahboobeh Sabeti Akbar-Abad
- Cellular and Molecular Research Center, Research Institute of Cellular and Molecular Sciences in Infectious Diseases, Zahedan University of Medical Sciences, Zahedan, Iran
- Department of Clinical Biochemistry, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Ramin Saravani
- Cellular and Molecular Research Center, Research Institute of Cellular and Molecular Sciences in Infectious Diseases, Zahedan University of Medical Sciences, Zahedan, Iran
- Department of Clinical Biochemistry, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran
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3
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Magni L, Yu H, Christensen NM, Poulsen MH, Frueh A, Deshar G, Johansen AZ, Johansen JS, Pless SA, Jørgensen NR, Novak I. Human P2X7 receptor variants Gly150Arg and Arg276His polymorphisms have differential effects on risk association and cellular functions in pancreatic cancer. Cancer Cell Int 2024; 24:148. [PMID: 38664691 PMCID: PMC11044319 DOI: 10.1186/s12935-024-03339-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Accepted: 04/18/2024] [Indexed: 04/29/2024] Open
Abstract
BACKGROUND The purinergic P2X7 receptor (P2X7R) plays an important role in the crosstalk between pancreatic stellate cells (PSCs) and cancer cells, thus promoting progression of pancreatic ductal adenocarcinoma (PDAC). Single nucleotide polymorphisms (SNPs) in the P2X7R have been reported for several cancers, but have not been explored in PDAC. MATERIALS AND METHODS Blood samples from PDAC patients and controls were genotyped for 11 non-synonymous SNPs in P2X7R and a risk analysis was performed. Relevant P2X7R-SNP GFP variants were expressed in PSCs and cancer cells and their function was assayed in the following tests. Responses in Ca2+ were studied with Fura-2 and dye uptake with YO-PRO-1. Cell migration was monitored by fluorescence microscopy. Released cytokines were measured with MSD assay. RESULTS Risk analysis showed that two SNPs 474G>A and 853G>A (rs28360447, rs7958316), that lead to the Gly150Arg and Arg276His variants, had a significant but opposite risk association with PDAC development, protecting against and predisposing to the disease, respectively. In vitro experiments performed on cancer cells and PSCs expressing the Gly150Arg variant showed reduced intracellular Ca2+ response, fluorescent dye uptake, and cell migration, while the Arg276His variant reduced dye uptake but displayed WT-like Ca2+ responses. As predicted, P2X7R was involved in cytokine release (IL-6, IL-1β, IL-8, TNF-α), but the P2X7R inhibitors displayed varied effects. CONCLUSION In conclusion, we provide evidence for the P2X7R SNPs association with PDAC and propose that they could be considered as potential biomarkers.
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Affiliation(s)
- Lara Magni
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen Ø, Denmark
| | - Haoran Yu
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen Ø, Denmark
| | - Nynne M Christensen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen Ø, Denmark
| | - Mette H Poulsen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Alexander Frueh
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen Ø, Denmark
| | - Ganga Deshar
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen Ø, Denmark
| | - Astrid Z Johansen
- Department of Oncology, Copenhagen University Hospital - Herlev and Gentofte Hospital, Herlev, Denmark
| | - Julia S Johansen
- Department of Oncology, Copenhagen University Hospital - Herlev and Gentofte Hospital, Herlev, Denmark
- Department of Medicine, Copenhagen University Hospital - Herlev and Gentofte, Herlev, Denmark
| | - Stephan A Pless
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Niklas R Jørgensen
- Department of Clinical Biochemistry, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ivana Novak
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen Ø, Denmark.
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4
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Olivier E, Rat P. Role of Oxysterols in Ocular Degeneration Mechanisms and Involvement of P2X7 Receptor. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1440:277-292. [PMID: 38036885 DOI: 10.1007/978-3-031-43883-7_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
Ocular degeneration, including cataracts, glaucoma, macular degeneration, and diabetic retinopathy, is a major public health challenge, as it affects the quality of life of millions of people worldwide and, in its advanced stages, leads to blindness. Ocular degeneration, although it can affect different parts of the eye, shares common characteristics such as oxysterols and the P2X7 receptor. Indeed, oxysterols, which are cholesterol derivatives, are associated with ocular degeneration pathogenesis and trigger inflammation and cell death pathways. Activation of the P2X7 receptor is also linked to ocular degeneration and triggers the same pathways. In age-related macular degeneration, these two key players have been associated, but further studies are needed to extrapolate this interrelationship to other ocular degenerations.
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Affiliation(s)
| | - Patrice Rat
- Université Paris Cité, CNRS, CiTCoM, Paris, France
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5
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Ronning KE, Déchelle-Marquet PA, Che Y, Guillonneau X, Sennlaub F, Delarasse C. The P2X7 Receptor, a Multifaceted Receptor in Alzheimer's Disease. Int J Mol Sci 2023; 24:11747. [PMID: 37511507 PMCID: PMC10380278 DOI: 10.3390/ijms241411747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 07/13/2023] [Accepted: 07/19/2023] [Indexed: 07/30/2023] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by impaired episodic memory and two pathological lesions: amyloid plaques and neurofibrillary tangles. In AD, damaged neurons and the accumulation of amyloid β (Aβ) peptides cause a significant release of high amounts of extracellular ATP, which acts as a danger signal. The purinergic receptor P2X7 is the main sensor of high concentrations of ATP, and P2X7 has been shown to be upregulated in the brains of AD patients, contributing to the disease's pathological processes. Further, there are many polymorphisms of the P2X7 gene that impact the risk of developing AD. P2X7 can directly modulate Aβ plaques and Tau protein lesions as well as the inflammatory response by regulating NLRP3 inflammasome and the expression of several chemokines. The significant role of microglial P2X7 in AD has been well established, although other cell types may also be important in P2X7-mediated mechanisms. In this review, we will discuss the different P2X7-dependent pathways involved in the development of AD.
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Affiliation(s)
- Kaitryn E Ronning
- INSERM, CNRS, Institut de la Vision, Sorbonne University, F-75012 Paris, France
| | | | - Yueshen Che
- INSERM, CNRS, Institut de la Vision, Sorbonne University, F-75012 Paris, France
| | - Xavier Guillonneau
- INSERM, CNRS, Institut de la Vision, Sorbonne University, F-75012 Paris, France
| | - Florian Sennlaub
- INSERM, CNRS, Institut de la Vision, Sorbonne University, F-75012 Paris, France
| | - Cécile Delarasse
- INSERM, CNRS, Institut de la Vision, Sorbonne University, F-75012 Paris, France
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6
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Molcak H, Jiang K, Campbell CJ, Matsubara JA. Purinergic signaling via P2X receptors and mechanisms of unregulated ATP release in the outer retina and age-related macular degeneration. Front Neurosci 2023; 17:1216489. [PMID: 37496736 PMCID: PMC10366617 DOI: 10.3389/fnins.2023.1216489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 06/26/2023] [Indexed: 07/28/2023] Open
Abstract
Age-related macular degeneration (AMD) is a chronic and progressive inflammatory disease of the retina characterized by photoceptor loss and significant central visual impairment due to either choroidal neovascularization or geographic atrophy. The pathophysiology of AMD is complex and multifactorial, driven by a combination of modifiable and non-modifiable risk factors, molecular mechanisms, and cellular processes that contribute to overall disease onset, severity, and progression. Unfortunately, due to the structural, cellular, and pathophysiologic complexity, therapeutic discovery is challenging. While purinergic signaling has been investigated for its role in the development and treatment of ocular pathologies including AMD, the potential crosstalk between known contributors to AMD, such as the complement cascade and inflammasome activation, and other biological systems, such as purinergic signaling, have not been fully characterized. In this review, we explore the interactions between purinergic signaling, ATP release, and known contributors to AMD pathogenesis including complement dysregulation and inflammasome activation. We begin by identifying what is known about purinergic receptors in cell populations of the outer retina and potential sources of extracellular ATP required to trigger purinergic receptor activation. Next, we examine evidence in the literature that the purinergic system accelerates AMD pathogenesis leading to apoptotic and pyroptotic cell death in retinal cells. To fully understand the potential role that purinergic signaling plays in AMD, more research is needed surrounding the expression, distribution, functions, and interactions of purinergic receptors within cells of the outer retina as well as potential crosstalk with other systems. By determining how these processes are affected in the context of purinergic signaling, it will improve our understanding of the mechanisms that drive AMD pathogenesis which is critical in developing treatment strategies that prevent or slow progression of the disease.
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Affiliation(s)
- Haydn Molcak
- Matsubara Lab, Faculty of Medicine, Department of Ophthalmology and Visual Sciences, Eye Care Centre, Vancouver, BC, Canada
| | - Kailun Jiang
- Matsubara Lab, Faculty of Medicine, Department of Ophthalmology and Visual Sciences, Eye Care Centre, Vancouver, BC, Canada
| | | | - Joanne A. Matsubara
- Matsubara Lab, Faculty of Medicine, Department of Ophthalmology and Visual Sciences, Eye Care Centre, Vancouver, BC, Canada
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7
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Ruamviboonsuk P, Lai TYY, Chen SJ, Yanagi Y, Wong TY, Chen Y, Gemmy Cheung CM, Teo KYC, Sadda S, Gomi F, Chaikitmongkol V, Chang A, Lee WK, Kokame G, Koh A, Guymer R, Lai CC, Kim JE, Ogura Y, Chainakul M, Arjkongharn N, Hong Chan H, Lam DSC. Polypoidal Choroidal Vasculopathy: Updates on Risk Factors, Diagnosis, and Treatments. Asia Pac J Ophthalmol (Phila) 2023; 12:184-195. [PMID: 36728294 DOI: 10.1097/apo.0000000000000573] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 09/09/2022] [Indexed: 02/03/2023] Open
Abstract
There have been recent advances in basic research and clinical studies in polypoidal choroidal vasculopathy (PCV). A recent, large-scale, population-based study found systemic factors, such as male gender and smoking, were associated with PCV, and a recent systematic review reported plasma C-reactive protein, a systemic biomarker, was associated with PCV. Growing evidence points to an association between pachydrusen, recently proposed extracellular deposits associated with the thick choroid, and the risk of development of PCV. Many recent studies on diagnosis of PCV have focused on applying criteria from noninvasive multimodal retinal imaging without requirement of indocyanine green angiography. There have been attempts to develop deep learning models, a recent subset of artificial intelligence, for detecting PCV from different types of retinal imaging modality. Some of these deep learning models were found to have high performance when they were trained and tested on color retinal images with corresponding images from optical coherence tomography. The treatment of PCV is either a combination therapy using verteporfin photodynamic therapy and anti-vascular endothelial growth factor (VEGF), or anti-VEGF monotherapy, often used with a treat-and-extend regimen. New anti-VEGF agents may provide more durable treatment with similar efficacy, compared with existing anti-VEGF agents. It is not known if they can induce greater closure of polypoidal lesions, in which case, combination therapy may still be a mainstay. Recent evidence supports long-term follow-up of patients with PCV after treatment for early detection of recurrence, particularly in patients with incomplete closure of polypoidal lesions.
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Affiliation(s)
| | - Timothy Y Y Lai
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Shih-Jen Chen
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Yasuo Yanagi
- Department of Ophthalmology and Microtechnology, Yokohama City University, Yokohama, Japan
| | - Tien Yin Wong
- Singapore National Eye Centre, Singapore, Singapore
- Duke-NUS Medical School, National University of Singapore, Singapore
- School of Medicine, Tsinghua University, Beijing, China
| | - Youxin Chen
- Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Chui Ming Gemmy Cheung
- Singapore National Eye Centre, Singapore, Singapore
- Duke-NUS Medical School, National University of Singapore, Singapore
| | - Kelvin Y C Teo
- Singapore National Eye Centre, Singapore, Singapore
- Duke-NUS Medical School, National University of Singapore, Singapore
- Singapore Eye Research Institute, Singapore, Singapore
| | - Srinivas Sadda
- Doheny Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Fumi Gomi
- Department of Ophthalmology, Hyogo Medical University, Hyogo, Japan
| | - Voraporn Chaikitmongkol
- Retina Division, Department of Ophthalmology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Andrew Chang
- Sydney Retina Clinic, Sydney Eye Hospital, University of Sydney, Sydney, NSW, Australia
| | | | - Gregg Kokame
- Division of Ophthalmology, Department of Surgery, University of Hawaii School of Medicine, Honolulu, HI
| | - Adrian Koh
- Eye & Retina Surgeons, Camden Medical Centre, Singapore, Singapore
| | - Robyn Guymer
- Centre for Eye Research Australia, University of Melbourne, The Royal Victorian Eye and Ear Hospital, Melbourne, Australia
| | - Chi-Chun Lai
- Department of Ophthalmology, Chang Gung Memorial Hospital, Keelung, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Judy E Kim
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, WI
| | - Yuichiro Ogura
- Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | | | | | | | - Dennis S C Lam
- The C-MER International Eye Research Center of The Chinese University of Hong Kong (Shenzhen), Shenzhen, China
- The C-MER Dennis Lam & Partners Eye Center, C-MER International Eye Care Group, Hong Kong, China
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8
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P2X7-dependent immune pathways in retinal diseases. Neuropharmacology 2023; 223:109332. [PMID: 36372269 DOI: 10.1016/j.neuropharm.2022.109332] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/28/2022] [Accepted: 11/09/2022] [Indexed: 11/13/2022]
Abstract
Adenosine triphosphate (ATP) is a signalling molecule acting as a neurotransmitter but also as a danger signal. The purinergic receptor P2X7 is the main sensor of high concentration of ATP released by damaged cells. In the eye, P2X7 is expressed by resident microglia and immune cells that infiltrate the retina in disease such as age-related macular degeneration (AMD), a degenerative retinal disease, and uveitis, an inflammatory eye disease. Activation of P2X7 is involved in several physiological and pathological processes: phagocytosis, activation of the inflammasome NLRP3, release of pro-inflammatory mediators and cell death. The aim of this review is to discuss the potential involvement of P2X7 in the development of AMD and uveitis.
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9
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John MC, Quinn J, Hu ML, Cehajic-Kapetanovic J, Xue K. Gene-agnostic therapeutic approaches for inherited retinal degenerations. Front Mol Neurosci 2023; 15:1068185. [PMID: 36710928 PMCID: PMC9881597 DOI: 10.3389/fnmol.2022.1068185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 12/12/2022] [Indexed: 01/11/2023] Open
Abstract
Inherited retinal diseases (IRDs) are associated with mutations in over 250 genes and represent a major cause of irreversible blindness worldwide. While gene augmentation or gene editing therapies could address the underlying genetic mutations in a small subset of patients, their utility remains limited by the great genetic heterogeneity of IRDs and the costs of developing individualised therapies. Gene-agnostic therapeutic approaches target common pathogenic pathways that drive retinal degeneration or provide functional rescue of vision independent of the genetic cause, thus offering potential clinical benefits to all IRD patients. Here, we review the key gene-agnostic approaches, including retinal cell reprogramming and replacement, neurotrophic support, immune modulation and optogenetics. The relative benefits and limitations of these strategies and the timing of clinical interventions are discussed.
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Affiliation(s)
- Molly C. John
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Joel Quinn
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Monica L. Hu
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Jasmina Cehajic-Kapetanovic
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Kanmin Xue
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
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10
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Shinozaki Y, Saito K, Kashiwagi K, Koizumi S. Ocular P2 receptors and glaucoma. Neuropharmacology 2023; 222:109302. [PMID: 36341810 DOI: 10.1016/j.neuropharm.2022.109302] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 10/08/2022] [Accepted: 10/21/2022] [Indexed: 11/06/2022]
Abstract
Adenosine triphosphate (ATP), an energy source currency in cells, is released or leaked to the extracellular space under both physiological and pathological conditions. Extracellular ATP functions as an intercellular signaling molecule through activation of purinergic P2 receptors. Ocular tissue and cells release ATP in response to physiological stimuli such as intraocular pressure (IOP), and P2 receptor activation regulates IOP elevation or reduction. Dysregulated purinergic signaling may cause abnormally elevated IOP, which is one of the major risk factors for glaucoma. Glaucoma, a leading cause of blindness worldwide, is characterized by progressive degeneration of optic nerves and retinal ganglion cells (RGCs), which are essential retinal neurons that transduce visual information to the brain. An elevation in IOP may stress RGCs and increase the risk for glaucoma pathogenesis. In the aqueous humor of human patients with glaucoma, the ATP level is significantly elevated. Such excess amount of ATP may directly cause RGC death via a specific subtype of P2 receptors. Dysregulated purinergic signaling may also trigger inflammation, oxidative stress, and excitotoxicity via activating non-neuronal cell types such as glial cells. In this review, we discussed the physiological roles of extracellular nucleotides in the ocular tissue and their potential role in the pathogenesis of glaucoma. This article is part of the Special Issue on 'Purinergic Signaling: 50 years'.
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Affiliation(s)
- Youichi Shinozaki
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan; Interdisciplinary Brain-Immune Research Center, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Kozo Saito
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Kenji Kashiwagi
- Department of Ophthalmology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan; Interdisciplinary Brain-Immune Research Center, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan.
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11
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Drysdale C, Park K, Vessey KA, Huang X, Caruso E, Li Y, Wong J, Wiley JS, Fletcher E, Guymer RH, Gu BJ. P2X7-mediated alteration of membrane fluidity is associated with the late stages of age-related macular degeneration. Purinergic Signal 2022; 18:469-479. [PMID: 36001279 PMCID: PMC9832188 DOI: 10.1007/s11302-022-09894-y] [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: 03/28/2022] [Accepted: 08/11/2022] [Indexed: 01/14/2023] Open
Abstract
We have shown deficits in monocyte phagocytosis from patients with age-related macular degeneration (AMD). Cell membrane fluidity is known to affect phagocytic capacity and leucocyte functionality more generally. Therefore, we examined membrane fluidity of peripheral blood leucocytes in human patients with AMD and in the P2X7 null mouse model of AMD using flow cytometry with a fluorescent probe for fluidity, TMA-DPH. The results showed that membrane fluidity was decreased in all leucocyte types of late AMD relative to healthy controls (HC) including monocytes, neutrophils and lymphocytes but this was not apparent in earlier stages of AMD. Further analysis of factors contributing to membrane fluidity indicated that pre-treatment of monocytes and lymphocytes with ATP greatly increased membrane fluidity in humans and mice. Evidence from P2X7 null mice and P2X7 antagonists confirmed that these ATP-driven increases in membrane fluidity were mediated by P2X7 but were not associated with the classic P2X7 functions of pore formation or phagocytosis. Analysis of P2X7 expression indicated that receptor levels were elevated in classic monocytes of late AMD patients, further suggesting the P2X7 may contribute to altered plasma membrane properties. Our findings identified a novel biological function of P2X7 in modulating membrane fluidity of leucocytes and demonstrated reduced membrane fluidity in cellular changes associated with the late stage of AMD.
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Affiliation(s)
- Candace Drysdale
- The Florey Institute, The University of Melbourne, 30 Royal Parade, Parkville, VIC 3052 Australia
| | - Keunha Park
- The Florey Institute, The University of Melbourne, 30 Royal Parade, Parkville, VIC 3052 Australia
| | - Kirstan A. Vessey
- Department of Anatomy & Physiology, The University of Melbourne, Melbourne, VIC Australia
| | - Xin Huang
- The Florey Institute, The University of Melbourne, 30 Royal Parade, Parkville, VIC 3052 Australia
| | - Emily Caruso
- Centre for Eye Research Australia, Department of Surgery (Ophthlamology), University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC Australia
| | - Yihan Li
- The Florey Institute, The University of Melbourne, 30 Royal Parade, Parkville, VIC 3052 Australia
| | - Joelyn Wong
- The Florey Institute, The University of Melbourne, 30 Royal Parade, Parkville, VIC 3052 Australia
| | - James S. Wiley
- The Florey Institute, The University of Melbourne, 30 Royal Parade, Parkville, VIC 3052 Australia
| | - Erica Fletcher
- Department of Anatomy & Physiology, The University of Melbourne, Melbourne, VIC Australia
| | - Robyn H. Guymer
- Centre for Eye Research Australia, Department of Surgery (Ophthlamology), University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC Australia
| | - Ben J. Gu
- The Florey Institute, The University of Melbourne, 30 Royal Parade, Parkville, VIC 3052 Australia
- National Clinical Research Center for Aging and Medicine, Huashan Hospital of Fudan University, Shanghai, China
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Martínez-Gil N, Kutsyr O, Noailles A, Fernández-Sánchez L, Vidal L, Sánchez-Sáez X, Sánchez-Castillo C, Lax P, Cuenca N, García AG, Maneu V. Purinergic Receptors P2X7 and P2X4 as Markers of Disease Progression in the rd10 Mouse Model of Inherited Retinal Dystrophy. Int J Mol Sci 2022; 23:ijms232314758. [PMID: 36499084 PMCID: PMC9739106 DOI: 10.3390/ijms232314758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 11/29/2022] Open
Abstract
The purinergic receptor P2X7 (P2X7R) is implicated in all neurodegenerative diseases of the central nervous system. It is also involved in the retinal degeneration associated with glaucoma, age-related macular degeneration, and diabetic retinopathy, and its overexpression in the retina is evident in these disorders. Retinitis pigmentosa is a progressive degenerative disease that ultimately leads to blindness. Here, we investigated the expression of P2X7R during disease progression in the rd10 mouse model of RP. As the purinergic receptor P2X4 is widely co-expressed with P2X7R, we also studied its expression in the retina of rd10 mice. The expression of P2X7R and P2X4R was examined by immunohistochemistry, flow cytometry, and western blotting. In addition, we analyzed retinal functionality by electroretinographic recordings of visual responses and optomotor tests and retinal morphology. We found that the expression of P2X7R and P2X4R increased in rd10 mice concomitant with disease progression, but with different cellular localization. Our findings suggest that P2X7R and P2X4R might play an important role in RP progression, which should be further analyzed for the pharmacological treatment of inherited retinal dystrophies.
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Affiliation(s)
- Natalia Martínez-Gil
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, 03690 Alicante, Spain
| | - Oksana Kutsyr
- Departamento de Óptica, Farmacología y Anatomía, Universidad de Alicante, 03690 Alicante, Spain
| | - Agustina Noailles
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, 03690 Alicante, Spain
| | - Laura Fernández-Sánchez
- Departamento de Óptica, Farmacología y Anatomía, Universidad de Alicante, 03690 Alicante, Spain
| | - Lorena Vidal
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, 03690 Alicante, Spain
| | - Xavier Sánchez-Sáez
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, 03690 Alicante, Spain
| | - Carla Sánchez-Castillo
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, 03690 Alicante, Spain
| | - Pedro Lax
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, 03690 Alicante, Spain
| | - Nicolás Cuenca
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, 03690 Alicante, Spain
| | - Antonio G. García
- Departamento de Farmacología y Terapéutica, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, 28029 Madrid, Spain
- Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa, 28006 Madrid, Spain
| | - Victoria Maneu
- Departamento de Óptica, Farmacología y Anatomía, Universidad de Alicante, 03690 Alicante, Spain
- Correspondence:
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The diagnostic yield, candidate genes, and pitfalls for a genetic study of intellectual disability in 118 middle eastern families. Sci Rep 2022; 12:18862. [PMID: 36344539 PMCID: PMC9640568 DOI: 10.1038/s41598-022-22036-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 10/07/2022] [Indexed: 11/09/2022] Open
Abstract
Global Developmental Delay/Intellectual disability (ID) is the term used to describe various disorders caused by abnormal brain development and characterized by impairments in cognition, communication, behavior, or motor skills. In the past few years, whole-exome sequencing (WES) has been proven to be a powerful, robust, and scalable approach for candidate gene discoveries in consanguineous populations. In this study, we recruited 215 patients affected with ID from 118 Middle Eastern families. Whole-exome sequencing was completed for 188 individuals. The average age at which WES was completed was 8.5 years. Pathogenic or likely pathogenic variants were detected in 32/118 families (27%). Variants of uncertain significance were seen in 33/118 families (28%). The candidate genes with a possible association with ID were detected in 32/118 (27%) with a total number of 64 affected individuals. These genes are novel, were previously reported in a single family, or cause strikingly different phenotypes with a different mode of inheritance. These genes included: AATK, AP1G2, CAMSAP1, CCDC9B, CNTROB, DNAH14, DNAJB4, DRG1, DTNBP1, EDRF1, EEF1D, EXOC8, EXOSC4, FARSB, FBXO22, FILIP1, INPP4A, P2RX7, PRDM13, PTRHD1, SCN10A, SCYL2, SMG8, SUPV3L1, TACC2, THUMPD1, XPR1, ZFYVE28. During the 5 years of the study and through gene matching databases, several of these genes have now been confirmed as causative of ID. In conclusion, understanding the causes of ID will help understand biological mechanisms, provide precise counseling for affected families, and aid in primary prevention.
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Wong JHC, Ma JYW, Jobling AI, Brandli A, Greferath U, Fletcher EL, Vessey KA. Exploring the pathogenesis of age-related macular degeneration: A review of the interplay between retinal pigment epithelium dysfunction and the innate immune system. Front Neurosci 2022; 16:1009599. [PMID: 36408381 PMCID: PMC9670140 DOI: 10.3389/fnins.2022.1009599] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 10/12/2022] [Indexed: 07/30/2023] Open
Abstract
Age-related macular degeneration (AMD) is a leading cause of irreversible vision loss in the older population. Classical hallmarks of early and intermediate AMD are accumulation of drusen, a waste deposit formed under the retina, and pigmentary abnormalities in the retinal pigment epithelium (RPE). When the disease progresses into late AMD, vision is affected due to death of the RPE and the light-sensitive photoreceptors. The RPE is essential to the health of the retina as it forms the outer blood retinal barrier, which establishes ocular immune regulation, and provides support for the photoreceptors. Due to its unique anatomical position, the RPE can communicate with the retinal environment and the systemic immune environment. In AMD, RPE dysfunction and the accumulation of drusen drive the infiltration of retinal and systemic innate immune cells into the outer retina. While recruited endogenous or systemic mononuclear phagocytes (MPs) contribute to the removal of noxious debris, the accumulation of MPs can also result in chronic inflammation and contribute to AMD progression. In addition, direct communication and indirect molecular signaling between MPs and the RPE may promote RPE cell death, choroidal neovascularization and fibrotic scarring that occur in late AMD. In this review, we explore how the RPE and innate immune cells maintain retinal homeostasis, and detail how RPE dysfunction and aberrant immune cell recruitment contribute to AMD pathogenesis. Evidence from AMD patients will be discussed in conjunction with data from preclinical models, to shed light on future therapeutic targets for the treatment of AMD.
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15
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Li Y, Huang X, Fowler C, Lim YY, Laws SM, Faux N, Doecke JD, Trounson B, Pertile K, Rumble R, Doré V, Villemagne VL, Rowe CC, Wiley JS, Maruff P, Masters CL, Gu BJ. Identification of Leukocyte Surface P2X7 as a Biomarker Associated with Alzheimer's Disease. Int J Mol Sci 2022; 23:ijms23147867. [PMID: 35887215 PMCID: PMC9322488 DOI: 10.3390/ijms23147867] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 07/10/2022] [Accepted: 07/12/2022] [Indexed: 02/04/2023] Open
Abstract
Alzheimer's disease (AD) has shown altered immune responses in the periphery. We studied P2X7 (a proinflammatory receptor and a scavenger receptor) and two integrins, CD11b and CD11c, on the surface of circulating leukocytes and analysed their associations with Aβ-PET, brain atrophy, neuropsychological assessments, and cerebrospinal fluid (CSF) biomarkers. Total 287 age-matched, sex-balanced participants were recruited in a discovery cohort and two validation cohorts through the AIBL study and studied using tri-colour flow cytometry. Our results demonstrated reduced expressions of P2X7, CD11b, and CD11c on leukocytes, particularly monocytes, in Aβ +ve cases compared with Aβ -ve controls. P2X7 and integrin downregulation was observed at pre-clinical stage of AD and stayed low throughout disease course. We further constructed a polygenic risk score (PRS) model based on 12 P2RX7 risk alleles to assess the genetic impact on P2X7 function in AIBL and ADNI cohorts. No significant association was identified between the P2RX7 gene and AD, indicating that P2X7 downregulation in AD is likely caused by environmental changes rather than genetic factors. In conclusion, the downregulation of P2X7 and integrins at pre-clinical stage of AD indicates altered pro-inflammatory responses, phagocytic functions, and migrating capabilities of circulating monocytes in early AD pathogenesis. Our study not only improves our understanding of peripheral immune involvement in early stage of AD but also provides more insights into novel biomarker development, diagnosis, and prognosis of AD.
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Affiliation(s)
- Yihan Li
- The Florey Institute, The University of Melbourne, 30 Royal Parade, Parkville, VIC 3052, Australia; (Y.L.); (X.H.); (C.F.); (B.T.); (K.P.); (R.R.); (J.S.W.); (P.M.); (C.L.M.)
| | - Xin Huang
- The Florey Institute, The University of Melbourne, 30 Royal Parade, Parkville, VIC 3052, Australia; (Y.L.); (X.H.); (C.F.); (B.T.); (K.P.); (R.R.); (J.S.W.); (P.M.); (C.L.M.)
| | - Christopher Fowler
- The Florey Institute, The University of Melbourne, 30 Royal Parade, Parkville, VIC 3052, Australia; (Y.L.); (X.H.); (C.F.); (B.T.); (K.P.); (R.R.); (J.S.W.); (P.M.); (C.L.M.)
| | - Yen Y. Lim
- School of Psychological Sciences, Turner Institute for Brain and Mental Health, Monash University, Clayton, VIC 3168, Australia; (Y.Y.L.); (V.D.)
| | - Simon M. Laws
- School of Medical and Health Sciences, Edith Cowan University, 270 Joondalup Drive, Joondalup, WA 6027, Australia;
| | - Noel Faux
- Melbourne Data Analytics Platform, Petascale Campus Initiative, The University of Melbourne, 21 Bedford St., North Melbourne, VIC 3051, Australia;
| | - James D. Doecke
- The Australian e-Health Research Centre, CSIRO, Brisbane, QLD 4029, Australia;
| | - Brett Trounson
- The Florey Institute, The University of Melbourne, 30 Royal Parade, Parkville, VIC 3052, Australia; (Y.L.); (X.H.); (C.F.); (B.T.); (K.P.); (R.R.); (J.S.W.); (P.M.); (C.L.M.)
| | - Kelly Pertile
- The Florey Institute, The University of Melbourne, 30 Royal Parade, Parkville, VIC 3052, Australia; (Y.L.); (X.H.); (C.F.); (B.T.); (K.P.); (R.R.); (J.S.W.); (P.M.); (C.L.M.)
| | - Rebecca Rumble
- The Florey Institute, The University of Melbourne, 30 Royal Parade, Parkville, VIC 3052, Australia; (Y.L.); (X.H.); (C.F.); (B.T.); (K.P.); (R.R.); (J.S.W.); (P.M.); (C.L.M.)
| | - Vincent Doré
- School of Psychological Sciences, Turner Institute for Brain and Mental Health, Monash University, Clayton, VIC 3168, Australia; (Y.Y.L.); (V.D.)
- Department of Molecular Imaging & Therapy, Austin Health, Melbourne, VIC 3084, Australia; (V.L.V.); (C.C.R.)
- Department of Medicine, The University of Melbourne, Melbourne, VIC 3084, Australia
| | - Victor L. Villemagne
- Department of Molecular Imaging & Therapy, Austin Health, Melbourne, VIC 3084, Australia; (V.L.V.); (C.C.R.)
- Department of Medicine, The University of Melbourne, Melbourne, VIC 3084, Australia
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Christopher C. Rowe
- Department of Molecular Imaging & Therapy, Austin Health, Melbourne, VIC 3084, Australia; (V.L.V.); (C.C.R.)
- Department of Medicine, The University of Melbourne, Melbourne, VIC 3084, Australia
| | - James S. Wiley
- The Florey Institute, The University of Melbourne, 30 Royal Parade, Parkville, VIC 3052, Australia; (Y.L.); (X.H.); (C.F.); (B.T.); (K.P.); (R.R.); (J.S.W.); (P.M.); (C.L.M.)
| | - Paul Maruff
- The Florey Institute, The University of Melbourne, 30 Royal Parade, Parkville, VIC 3052, Australia; (Y.L.); (X.H.); (C.F.); (B.T.); (K.P.); (R.R.); (J.S.W.); (P.M.); (C.L.M.)
- CogState Ltd., Melbourne, VIC 3001, Australia
| | - Colin L. Masters
- The Florey Institute, The University of Melbourne, 30 Royal Parade, Parkville, VIC 3052, Australia; (Y.L.); (X.H.); (C.F.); (B.T.); (K.P.); (R.R.); (J.S.W.); (P.M.); (C.L.M.)
| | - Ben J. Gu
- The Florey Institute, The University of Melbourne, 30 Royal Parade, Parkville, VIC 3052, Australia; (Y.L.); (X.H.); (C.F.); (B.T.); (K.P.); (R.R.); (J.S.W.); (P.M.); (C.L.M.)
- National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai 200040, China
- Correspondence: ; Tel.: +61-3-9035-6317
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16
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Bianca Maria Platania C, Drago F, Bucolo C. The P2X7 receptor as a new pharmacological target for retinal diseases. Biochem Pharmacol 2022; 198:114942. [DOI: 10.1016/j.bcp.2022.114942] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 01/28/2022] [Accepted: 01/31/2022] [Indexed: 11/02/2022]
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17
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Ren W, Rubini P, Tang Y, Engel T, Illes P. Inherent P2X7 Receptors Regulate Macrophage Functions during Inflammatory Diseases. Int J Mol Sci 2021; 23:ijms23010232. [PMID: 35008658 PMCID: PMC8745241 DOI: 10.3390/ijms23010232] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 12/21/2021] [Accepted: 12/21/2021] [Indexed: 12/12/2022] Open
Abstract
Macrophages are mononuclear phagocytes which derive either from blood-borne monocytes or reside as resident macrophages in peripheral (Kupffer cells of the liver, marginal zone macrophages of the spleen, alveolar macrophages of the lung) and central tissue (microglia). They occur as M1 (pro-inflammatory; classic) or M2 (anti-inflammatory; alternatively activated) phenotypes. Macrophages possess P2X7 receptors (Rs) which respond to high concentrations of extracellular ATP under pathological conditions by allowing the non-selective fluxes of cations (Na+, Ca2+, K+). Activation of P2X7Rs by still higher concentrations of ATP, especially after repetitive agonist application, leads to the opening of membrane pores permeable to ~900 Da molecules. For this effect an interaction of the P2X7R with a range of other membrane channels (e.g., P2X4R, transient receptor potential A1 [TRPA1], pannexin-1 hemichannel, ANO6 chloride channel) is required. Macrophage-localized P2X7Rs have to be co-activated with the lipopolysaccharide-sensitive toll-like receptor 4 (TLR4) in order to induce the formation of the inflammasome 3 (NLRP3), which then activates the pro-interleukin-1β (pro-IL-1β)-degrading caspase-1 to lead to IL-1β release. Moreover, inflammatory diseases (e.g., rheumatoid arthritis, Crohn’s disease, sepsis, etc.) are generated downstream of the P2X7R-induced upregulation of intracellular second messengers (e.g., phospholipase A2, p38 mitogen-activated kinase, and rho G proteins). In conclusion, P2X7Rs at macrophages appear to be important targets to preserve immune homeostasis with possible therapeutic consequences.
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Affiliation(s)
- Wenjing Ren
- International Collaborative Centre on Big Science Plan for Purinergic Signalling, Chengdu University of TCM, Chengdu 610075, China; (W.R.); (P.R.); (Y.T.)
- School of Acupunct3ure and Tuina, Chengdu University of TCM, Chengdu 610075, China
| | - Patrizia Rubini
- International Collaborative Centre on Big Science Plan for Purinergic Signalling, Chengdu University of TCM, Chengdu 610075, China; (W.R.); (P.R.); (Y.T.)
- School of Acupunct3ure and Tuina, Chengdu University of TCM, Chengdu 610075, China
| | - Yong Tang
- International Collaborative Centre on Big Science Plan for Purinergic Signalling, Chengdu University of TCM, Chengdu 610075, China; (W.R.); (P.R.); (Y.T.)
- School of Acupunct3ure and Tuina, Chengdu University of TCM, Chengdu 610075, China
| | - Tobias Engel
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, D02 YN77 Dublin, Ireland;
- FutureNeuro, SFI Research Centre for Chronic and Rare Neurological Diseases, RCSI University of Medicine and Health Sciences, D02 YN77 Dublin, Ireland
| | - Peter Illes
- International Collaborative Centre on Big Science Plan for Purinergic Signalling, Chengdu University of TCM, Chengdu 610075, China; (W.R.); (P.R.); (Y.T.)
- School of Acupunct3ure and Tuina, Chengdu University of TCM, Chengdu 610075, China
- Rudolf Boehm Institute for Pharmacology and Toxicology, University of Leipzig, 04107 Leipzig, Germany
- Correspondence:
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18
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Wu Z, Fletcher EL, Kumar H, Greferath U, Guymer RH. Reticular pseudodrusen: A critical phenotype in age-related macular degeneration. Prog Retin Eye Res 2021; 88:101017. [PMID: 34752916 DOI: 10.1016/j.preteyeres.2021.101017] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 10/07/2021] [Accepted: 10/29/2021] [Indexed: 12/18/2022]
Abstract
Reticular pseudodrusen (RPD), or subretinal drusenoid deposits (SDD), refer to distinct lesions that occur in the subretinal space. Over the past three decades, their presence in association with age-related macular degeneration (AMD) has become increasingly recognized, especially as RPD have become more easily distinguished with newer clinical imaging modalities. There is also an increasing appreciation that RPD appear to be a critical AMD phenotype, where understanding their pathogenesis will provide further insights into the processes driving vision loss in AMD. However, key barriers to understanding the current evidence related to the independent impact of RPD include the heterogeneity in defining their presence, and failure to account for the confounding impact of the concurrent presence and severity of AMD pathology. This review thus critically discusses the current evidence on the prevalence and clinical significance of RPD and proposes a clinical imaging definition of RPD that will help move the field forward in gathering further key knowledge about this critical phenotype. It also proposes a putative mechanism for RPD formation and how they may drive progression to vision loss in AMD, through examining current evidence and presenting novel findings from preclinical and clinical studies.
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Affiliation(s)
- Zhichao Wu
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia; Ophthalmology, Department of Surgery, The University of Melbourne, Melbourne, Australia
| | - Erica L Fletcher
- Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC, Australia
| | - Himeesh Kumar
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia; Ophthalmology, Department of Surgery, The University of Melbourne, Melbourne, Australia
| | - Ursula Greferath
- Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC, Australia
| | - Robyn H Guymer
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia; Ophthalmology, Department of Surgery, The University of Melbourne, Melbourne, Australia.
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Du Y, Kong N, Zhang J. Genetic Mechanism Revealed of Age-Related Macular Degeneration Based on Fusion of Statistics and Machine Learning Method. Front Genet 2021; 12:726599. [PMID: 34422023 PMCID: PMC8375266 DOI: 10.3389/fgene.2021.726599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 07/13/2021] [Indexed: 11/13/2022] Open
Abstract
Age-related macular degeneration (AMD) is the most common cause of irreversible vision loss in the developed world which affects the quality of life for millions of elderly individuals worldwide. Genome-wide association studies (GWAS) have identified genetic variants at 34 loci contributing to AMD. To better understand the disease pathogenesis and identify causal genes for AMD, we applied random walk (RW) and support vector machine (SVM) to identify AMD-related genes based on gene interaction relationship and significance of genes. Our model achieved 0.927 of area under the curve (AUC), and 65 novel genes have been identified as AMD-related genes. To verify our results, a statistics method called summary data-based Mendelian randomization (SMR) has been implemented to integrate GWAS data and transcriptome data to verify AMD susceptibility-related genes. We found 45 genes are related to AMD by SMR. Among these genes, 37 genes overlap with those found by SVM-RW. Finally, we revealed the biological process of genetic mutations leading to changes in gene expression leading to AMD. Our results reveal the genetic pathogenic factors and related mechanisms of AMD.
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Affiliation(s)
- Yongyi Du
- Department of Ophthalmology, Panyu Central Hospital, Guangzhou, China
| | - Ning Kong
- Department of Ophthalmology, Panyu Central Hospital, Guangzhou, China
| | - Jibin Zhang
- Department of Stomatology, Panyu Central Hospital, Guangzhou, China
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20
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Li L, Liu J, Xu A, Heiduschka P, Eter N, Chen C. Expression of purinergic receptors on microglia in the animal model of choroidal neovascularisation. Sci Rep 2021; 11:12389. [PMID: 34117330 PMCID: PMC8196182 DOI: 10.1038/s41598-021-91989-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 05/27/2021] [Indexed: 11/09/2022] Open
Abstract
To investigate the effect of P2 receptor on microglia and its inhibitor PPADS on choroidal neovascularization. Forty CX3CR1GFP/+ mice were randomly divided into 8 groups. In addition to the normal group, the rest of groups were receiving laser treatment. The retina and choroid from the second, third, fourth and fifth group of mice were taken in the 1, 4, 7, 14 days after laser treatment. The mice in the sixth and seventh group received intravitreal injection of 2 µl PPADS or PBS respectively immediately after laser treatment. The mice in the eighth group received topical application of PPADS once per day of three days. The mice in sixth, seventh and eighth group received AF and FFA examination on the fourth day after laser treatment. Immunofluorescence histochemical staining and real-time quantitative PCR were used to evaluate P2 expression and its effect on choroidal neovascularization. After laser treatment, activated microglia can express P2 receptors (P2X4, P2X7, P2Y2 and P2Y12). The expression of P2 increased on the first day after laser damage, peaked on the fourth day (tP2X4 = 6.05, tP2X7 = 2.95, tP2Y2 = 3.67, tP2Y12 = 5.98, all P < 0.01), and then decreased. After PPADS inhibition, compared with the PBS injection group, the mRNA of P2X4, P2X7, P2Y2 and P2Y12 were decreased significantly in the PPADS injection group (tP2X4 = 5.54, tP2X7 = 9.82, tP2Y2 = 3.86, tP2Y12 = 7.91, all P < 0.01) and the PPADS topical application group (tP2X4 = 3.24, tP2X7 = 5.89, tP2Y2 = 6.75, tP2Y12 = 4.97, all P < 0.01). Compared with the PBS injection group, not only the activity of microglia cells but also the leakage of CNV decreased significantly (P < 0.01) in the PPADS injection group and the PPADS topical application group. But between two PPADS groups, the leakage of CNV had no difference (P = 0.864). After laser induced CNV, activated microglia can express P2 receptors. The P2 receptor inhibitor, PPADS, can significantly affect the function of microglia and inhibit the formation of choroidal neovascularization.
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Affiliation(s)
- Lu Li
- Department of Ophthalmology, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei Province, 430060, People's Republic of China.
| | - Juejun Liu
- Department of Ophthalmology, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei Province, 430060, People's Republic of China
| | - Amin Xu
- Department of Ophthalmology, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei Province, 430060, People's Republic of China
| | - Peter Heiduschka
- Department of Ophthalmology, University of Münster Medical School, Domagkstr. 15, 48149, Münster, Germany
| | - Nicole Eter
- Department of Ophthalmology, University of Münster Medical School, Domagkstr. 15, 48149, Münster, Germany
| | - Changzheng Chen
- Department of Ophthalmology, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei Province, 430060, People's Republic of China
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21
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Kanellopoulos JM, Almeida-da-Silva CLC, Rüütel Boudinot S, Ojcius DM. Structural and Functional Features of the P2X4 Receptor: An Immunological Perspective. Front Immunol 2021; 12:645834. [PMID: 33897694 PMCID: PMC8059410 DOI: 10.3389/fimmu.2021.645834] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 03/04/2021] [Indexed: 12/14/2022] Open
Abstract
Extracellular nucleotides are important mediators of activation, triggering various responses through plasma membrane P2 and P1 receptors. P2 receptors are further subdivided into ionotropic P2X receptors and G protein-coupled P2Y receptors. P2X4 is an ATP-gated cation channel broadly expressed in most tissues of the body. Within the P2X family, P2X4 has a unique subcellular distribution, being preferentially localized in lysosomes. In these organelles, high ATP concentrations do not trigger P2X4 because of the low pH. However, when the pH increases to 7.4, P2X4 can be stimulated by intra-lysosomal ATP, which is in its active, tetra-anionic form. Elucidation of P2X4, P2X3 and P2X7 structures has shed some light on the functional differences between these purinergic receptors. The potential interaction between P2X4 and P2X7 has been extensively studied. Despite intensive effort, it has not been possible yet to determine whether P2X4 and P2X7 interact as heterotrimers or homotrimers at the plasma membrane. However, several publications have shown that functional interactions between P2X4 and P2X7 do occur. Importantly, these studies indicate that P2X4 potentiates P2X7-dependent activation of inflammasomes, leading to increased release of IL-1β and IL-18. The role of P2X4 in various diseases could be beneficial or deleterious even though the pathophysiological mechanisms involved are still poorly defined. However, in diseases whose physiopathology involves activation of the NLRP3 inflammasome, P2X4 was found to exacerbate severity of disease. The recent production of monoclonal antibodies specific for the human and mouse P2X4, some of which are endowed with agonist or antagonist properties, raises the possibility that they could be used therapeutically. Analysis of single nucleotide polymorphisms of the human P2RX4 gene has uncovered the association of P2RX4 gene variants with susceptibility to several human diseases.
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Affiliation(s)
- Jean M Kanellopoulos
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | | | - Sirje Rüütel Boudinot
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - David M Ojcius
- Department of Biomedical Sciences, University of the Pacific, Arthur A. Dugoni School of Dentistry, San Francisco, CA, United States
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22
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Gu BJ, Huang X, Avula PK, Caruso E, Drysdale C, Vessey KA, Ou A, Fowler C, Liu TH, Lin Y, Horton A, Masters CL, Wiley JS, Guymer RH, Fletcher EL. Deficits in Monocyte Function in Age Related Macular Degeneration: A Novel Systemic Change Associated With the Disease. Front Med (Lausanne) 2021; 8:634177. [PMID: 33816525 PMCID: PMC8010137 DOI: 10.3389/fmed.2021.634177] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 02/24/2021] [Indexed: 12/25/2022] Open
Abstract
Age-related macular degeneration (AMD) is characterized by the accumulation of debris in the posterior eye. In this study we evaluated peripheral blood monocyte phagocytic function at various stages of AMD and in aged matched control participants. Real-time tri-color flow cytometry was used to quantify phagocytic function of peripheral blood monocyte subsets (non-classic, intermediate and classic) isolated from subjects with intermediate or late AMD and compared with age matched healthy controls. Assessment of phagocytic function of monocytes isolated from those with and without reticular pseudodrusen was also made, and the effect of glatiramer acetate on phagocytic function assessed. Phagocytic function was reduced in all subjects with AMD, irrespective of stage of disease. However, there was no correlation between phagocytic function and drusen load, nor any difference between the level of phagocytosis in those with or without reticular pseudodrusen. Treatment with glatiramer acetate increased phagocytosis of classical and non-classical monocytes, normalizing the reduction in phagocytosis observed in those with AMD. These findings suggest that defective systemic phagocytosis is associated with both intermediate and late stages of AMD, highlighting a potential role in the accumulation of debris that occurs early in the disease process. Assessing peripheral monocyte phagocytic function provides further insights into the etiology of this disease and offer a novel therapeutic target.
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Affiliation(s)
- Ben J Gu
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.,National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Xin Huang
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Pavan K Avula
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Emily Caruso
- Department of Surgery (Ophthalmology), Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne, East Melbourne, VIC, Australia
| | - Candace Drysdale
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Kirstan A Vessey
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, VIC, Australia
| | - Amber Ou
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Christopher Fowler
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Tian-Hua Liu
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Yong Lin
- National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Adam Horton
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Colin L Masters
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - James S Wiley
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Robyn H Guymer
- Department of Surgery (Ophthalmology), Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne, East Melbourne, VIC, Australia
| | - Erica L Fletcher
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, VIC, Australia
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23
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Zhao YF, Tang Y, Illes P. Astrocytic and Oligodendrocytic P2X7 Receptors Determine Neuronal Functions in the CNS. Front Mol Neurosci 2021; 14:641570. [PMID: 33642994 PMCID: PMC7906075 DOI: 10.3389/fnmol.2021.641570] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 01/19/2021] [Indexed: 12/20/2022] Open
Abstract
P2X7 receptors are members of the ATP-gated cationic channel family with a preferential localization at the microglial cells, the resident macrophages of the brain. However, these receptors are also present at neuroglia (astrocytes, oligodendrocytes) although at a considerably lower density. They mediate necrosis/apoptosis by the release of pro-inflammatory cytokines/chemokines, reactive oxygen species (ROS) as well as the excitotoxic (glio)transmitters glutamate and ATP. Besides mediating cell damage i.e., superimposed upon chronic neurodegenerative processes in Alzheimer’s Disease, Parkinson’s Disease, multiple sclerosis, and amyotrophic lateral sclerosis, they may also participate in neuroglial signaling to neurons under conditions of high ATP concentrations during any other form of neuroinflammation/neurodegeneration. It is a pertinent open question whether P2X7Rs are localized on neurons, or whether only neuroglia/microglia possess this receptor-type causing indirect effects by releasing the above-mentioned signaling molecules. We suggest as based on molecular biology and functional evidence that neurons are devoid of P2X7Rs although the existence of neuronal P2X7Rs cannot be excluded with absolute certainty.
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Affiliation(s)
- Ya-Fei Zhao
- School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Yong Tang
- School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu, China.,International Collaborative Center on Big Science Plan for Purine Signaling, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Peter Illes
- School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu, China.,International Collaborative Center on Big Science Plan for Purine Signaling, Chengdu University of Traditional Chinese Medicine, Chengdu, China.,Rudolf Boehm Institute for Pharmacology and Toxicology, University of Leipzig, Leipzig, Germany
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24
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Zhu Y, Chen X, Lu Y, Fan S, Yang Y, Chen Q, Huang Q, Xia L, Wei Y, Zheng J, Liu X. Diphenyleneiodonium enhances P2X7 dependent non-opsonized phagocytosis and suppresses inflammasome activation via blocking CX43-mediated ATP leakage. Pharmacol Res 2021; 166:105470. [PMID: 33529751 DOI: 10.1016/j.phrs.2021.105470] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 01/20/2021] [Accepted: 01/25/2021] [Indexed: 12/20/2022]
Abstract
The beneficial effects of antioxidants against oxidative stress have been well described. However, the pharmacological impacts of antioxidants other than inhibiting the production of reactive oxygen species (ROS) remain less understood. This study demonstrated that diphenyleneiodonium (DPI), a canonical NADPH oxidase 2 (NOX2) inhibitor, effectively promoted non-opsonized bacterial phagocytosis. Indeed, DPI abrogated the elevation in the extracellular ATP level of Escherichia coli (E. coli) -infected murine peritoneal macrophages, thereby restoring the association of the purinergic receptor P2X7 with non-muscle myosin heavy chain 9 (MYH9) to upregulate the P2X7 -dependent phagocytosis of E. coli. DPI also suppressed inflammasome activation and reduced necroptosis in E. coli-infected macrophages by decreasing extracellular ATP levels. Mechanistically, DPI upregulated p38 MAPK phosphorylation to suppress the expression and activity of the hemichannel protein connexin 43 (CX43), leading to the inhibition of CX43-mediated ATP efflux in E. coli-infected macrophages. In a murine E. coli infection model, DPI effectively reduced ATP release, decreased bacterial load and inhibited inflammasome activation, thereby improving survival and ameliorating organ injuries in model mice. In summary, our study demonstrates a previously unknown function of DPI in conferring protection against bacterial infection and suggests a putative antimicrobial strategy of modulating CX43 -dependent ATP leakage.
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Affiliation(s)
- Yuanfeng Zhu
- Clinical Medical Research Center, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Xiaoli Chen
- Clinical Medical Research Center, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Yongling Lu
- Clinical Medical Research Center, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Shijun Fan
- Clinical Medical Research Center, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Yongjun Yang
- Clinical Medical Research Center, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Qian Chen
- Clinical Medical Research Center, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Qianying Huang
- Clinical Medical Research Center, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Lin Xia
- Clinical Medical Research Center, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Yan Wei
- Clinical Medical Research Center, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Jiang Zheng
- Clinical Medical Research Center, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Xin Liu
- Clinical Medical Research Center, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China.
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25
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Li H, Cvejic E, Gu B, Vollmer-Conna U, Hickie I, Wakefield D, Davenport T, Wiley J, Lloyd AR. Regulation of the Acute Sickness Response by the P2RX7 Receptor. J Infect Dis 2021; 224:914-920. [PMID: 33471105 DOI: 10.1093/infdis/jiab027] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 01/14/2021] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND The acute sickness response to infection is a stereotyped set of illness manifestations initiated by proinflammatory signals in the periphery but mediated centrally. P2RX7 is a highly polymorphic gene encoding an ATP-gated cationic pore, widely expressed on immune cells and the brain, and regulating the NLRP3 inflammasome, as well as diverse neural functions. METHODS Associations between P2RX7 genotype, pore activity, and illness manifestations were examined in a cohort with acute viral and bacterial infections (n = 484). Genotyping of 12 P2RX7 function-modifying single-nucleotide polymorphisms (SNPs) was used to identify haplotypes and diplotypes. Leucocyte pore activity was measured by uptake of the fluorescent dye, YO-PRO-1, and by ATP-induced interleukin-1β (IL-1β) release. Associations were sought with scores describing the symptom domains, or endophenotypes, derived from principal components analysis. RESULTS Among the 12 SNPs, a 4-SNP haplotype block with 5 variants was found in 99.5% of the subjects. These haplotypes and diplotypes were closely associated with variations in pore activity and IL-1β production. Homozygous diplotypes were associated with overall illness severity as well as fatigue, pain, and mood disturbances. CONCLUSIONS P2RX7 signaling plays a significant role in the acute sickness response to infection, likely acting in both the immune system and the brain.
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Affiliation(s)
- Hui Li
- Viral Immunology Systems Program, Kirby Institute, University of New South Wales, Sydney, Australia
| | - Erin Cvejic
- Department of Human Behaviour, School of Psychiatry, University of New South Wales, Sydney, Australia
| | - Ben Gu
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Ute Vollmer-Conna
- Department of Human Behaviour, School of Psychiatry, University of New South Wales, Sydney, Australia
| | - Ian Hickie
- Brain and Mind Centre, University of Sydney, Sydney, Australia
| | - Denis Wakefield
- School of Medical Sciences, University of New South Wales, Sydney, Australia
| | | | - James Wiley
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Andrew R Lloyd
- Viral Immunology Systems Program, Kirby Institute, University of New South Wales, Sydney, Australia
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26
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Immunological Aspects of Age-Related Macular Degeneration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1256:143-189. [PMID: 33848001 DOI: 10.1007/978-3-030-66014-7_6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Increasing evidence over the past two decades points to a pivotal role for immune mechanisms in age-related macular degeneration (AMD) pathobiology. In this chapter, we will explore immunological aspects of AMD, with a specific focus on how immune mechanisms modulate clinical phenotypes of disease and severity and how components of the immune system may serve as triggers for disease progression in both dry and neovascular AMD. We will briefly review the biology of the immune system, defining the role of immune mechanisms in chronic degenerative disease and differentiating from immune responses to acute injury or infection. We will explore current understanding of the roles of innate immunity (especially macrophages), antigen-specific immunity (T cells, B cells, and autoimmunity), immune amplifications systems, especially complement activity and the NLRP3 inflammasome, in the pathogenesis of both dry and neovascular AMD, reviewing data from pathology, experimental animal models, and clinical studies of AMD patients. We will also assess how interactions between the immune system and infectious pathogens could potentially modulate AMD pathobiology via alterations in in immune effector mechanisms. We will conclude by reviewing the paradigm of "response to injury," which provides a means to integrate various immunologic mechanisms along with nonimmune mechanisms of tissue injury and repair as a model to understand the pathobiology of AMD.
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27
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Innate Immunity in Age-Related Macular Degeneration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1256:121-141. [PMID: 33848000 DOI: 10.1007/978-3-030-66014-7_5] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Multiple lines of investigation have demonstrated that inflammation plays significant roles in etiology of age-related macular degeneration (AMD). Although interventional trials in AMD therapy targeting inflammatory pathways have been conducted, they have not yet been successful and a detailed understanding as to why some have failed is still elusive. One limitation is the relative dearth of information on how immune cells interact with retinal cells to generate AMD phenotypes at each disease stage. Here, we summarize current research evidence and hypotheses regarding potential pathogenic roles of innate immune cells in the eye, which include resident retinal microglia, macrophages derived from infiltrating systemic monocytes, and macrophages resident in the choroid. We relate recent findings regarding the physiology, function, and cellular interactions involving innate immune cells in the retina and choroid to AMD-related processes, including: (1) drusen formation and regression, (2) the onset and spread of degeneration in late atrophic AMD, and (3) the initiation, growth, and exudation of neovascular vessels in late "wet" AMD. Understanding how innate immune cells contribute to specific AMD phenotypes can assist in generating a comprehensive view on the inflammatory etiology of AMD and aid in identifying anti-inflammatory therapeutic strategies and selecting appropriate clinical outcomes for the planned interventions.
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28
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Soundara Pandi SP, Ratnayaka JA, Lotery AJ, Teeling JL. Progress in developing rodent models of age-related macular degeneration (AMD). Exp Eye Res 2020; 203:108404. [PMID: 33340497 DOI: 10.1016/j.exer.2020.108404] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 12/13/2020] [Accepted: 12/14/2020] [Indexed: 12/25/2022]
Abstract
Age-related macular degeneration (AMD) is the leading cause of irreversible central vision loss, typically affecting individuals from mid-life onwards. Its multifactorial aetiology and the lack of any effective treatments has spurred the development of animal models as research and drug discovery tools. Several rodent models have been developed which recapitulate key features of AMD and provide insights into its underlying pathology. These have contributed to making significant progress in understanding the disease and the identification of novel therapeutic targets. However, a major caveat with existing models is that they do not demonstrate the full disease spectrum. In this review, we outline advances in rodent AMD models from the last decade. These models feature various hallmarks associated with AMD, including oxidative stress, hypoxia, immune dysregulation, genetic mutations and environmental risk factors. The review summarises the methods by which each model was created, its pathological characteristics as well as its relation to the disease in humans.
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Affiliation(s)
- Sudha Priya Soundara Pandi
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - J Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom.
| | - Andrew J Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom; Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, SO16 6YD, United Kingdom.
| | - Jessica L Teeling
- Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, MP840, Tremona Road, Southampton, SO16 6YD, United Kingdom.
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29
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Fletcher EL. Advances in understanding the mechanisms of retinal degenerations. Clin Exp Optom 2020; 103:723-732. [PMID: 33090561 DOI: 10.1111/cxo.13146] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 08/21/2020] [Accepted: 08/23/2020] [Indexed: 01/13/2023] Open
Abstract
Photoreceptor death is an important contributor to irreversible vision loss worldwide. In this review, I outline our work examining the role that purines, such as adenosine triphosphate (ATP), have in normal retinal function and in retinal disease. Our work shows that the actions of ATP, mediated by P2X receptors, are expressed in various retinal layers including photoreceptor terminals, and when stimulated by excessive levels of ATP is associated with rapid death of neurons. Treatment with a compound that blocks the action of P2X and some P2Y receptors reduces photoreceptor death in a mouse model of retinal degeneration. Our observations not only provide a means for developing a potential treatment for reducing photoreceptor death, but also provides a novel way of studying the neural plasticity effects that develop in the inner retina following photoreceptor death. There are a range of inner retinal changes that could influence the effectiveness of retinal prostheses. Indeed, using an ATP-induced degeneration model, we established that the amount of electrical stimulation required to elicit a response in the visual cortex was affected by the level of glial scarring. However, changes in P2X7 receptor expression by OFF ganglion cells during retinal degeneration can also be exploited by photoswitches to restore light sensitivity to degenerated retinae. Finally, our work has also considered how P2X7 expression by innate immune cells, and its role as a scavenger receptor, contributes to age-related macular degeneration (AMD). Our results show that loss of P2X7 function is associated with thickening of Bruch's membrane as well as increased risk of advanced disease in people with AMD. Overall, our work over the last 20 years highlights the importance of purinergic signalling in normal retinal function and retinal disease and suggest that developing therapies that target P2X7 function could be of benefit for these diseases.
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Affiliation(s)
- Erica L Fletcher
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
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30
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Calzaferri F, Ruiz-Ruiz C, de Diego AMG, de Pascual R, Méndez-López I, Cano-Abad MF, Maneu V, de Los Ríos C, Gandía L, García AG. The purinergic P2X7 receptor as a potential drug target to combat neuroinflammation in neurodegenerative diseases. Med Res Rev 2020; 40:2427-2465. [PMID: 32677086 DOI: 10.1002/med.21710] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 06/22/2020] [Accepted: 06/27/2020] [Indexed: 12/25/2022]
Abstract
Neurodegenerative diseases (NDDs) represent a huge social burden, particularly in Alzheimer's disease (AD) in which all proposed treatments investigated in murine models have failed during clinical trials (CTs). Thus, novel therapeutic strategies remain crucial. Neuroinflammation is a common pathogenic feature of NDDs. As purinergic P2X7 receptors (P2X7Rs) are gatekeepers of inflammation, they could be developed as drug targets for NDDs. Herein, we review this challenging hypothesis and comment on the numerous studies that have investigated P2X7Rs, emphasizing their molecular structure and functions, as well as their role in inflammation. Then, we elaborate on research undertaken in the field of medicinal chemistry to determine potential P2X7R antagonists. Subsequently, we review the state of neuroinflammation and P2X7R expression in the brain, in animal models and patients suffering from AD, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, multiple sclerosis, and retinal degeneration. Next, we summarize the in vivo studies testing the hypothesis that by mitigating neuroinflammation, P2X7R blockers afford neuroprotection, increasing neuroplasticity and neuronal repair in animal models of NDDs. Finally, we reviewed previous and ongoing CTs investigating compounds directed toward targets associated with NDDs; we propose that CTs with P2X7R antagonists should be initiated. Despite the high expectations for putative P2X7Rs antagonists in various central nervous system diseases, the field is moving forward at a relatively slow pace, presumably due to the complexity of P2X7Rs. A better pharmacological approach to combat NDDs would be a dual strategy, combining P2X7R antagonism with drugs targeting a selective pathway in a given NDD.
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Affiliation(s)
- Francesco Calzaferri
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Cristina Ruiz-Ruiz
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Antonio M G de Diego
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria, Hospital Universitario de La Princesa, Universidad Autónoma de Madrid, Madrid, Spain
| | - Ricardo de Pascual
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Iago Méndez-López
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - María F Cano-Abad
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria, Hospital Universitario de La Princesa, Universidad Autónoma de Madrid, Madrid, Spain
| | - Victoria Maneu
- Departamento de Óptica, Farmacología y Anatomía, Universidad de Alicante, San Vicente del Raspeig, Spain
| | - Cristóbal de Los Ríos
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria, Hospital Universitario de La Princesa, Universidad Autónoma de Madrid, Madrid, Spain
| | - Luis Gandía
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Antonio G García
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria, Hospital Universitario de La Princesa, Universidad Autónoma de Madrid, Madrid, Spain
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31
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Sophocleous RA, Berg T, Finol-Urdaneta RK, Sluyter V, Keshiya S, Bell L, Curtis SJ, Curtis BL, Seavers A, Bartlett R, Dowton M, Stokes L, Ooi L, Sluyter R. Pharmacological and genetic characterisation of the canine P2X4 receptor. Br J Pharmacol 2020; 177:2812-2829. [PMID: 32017039 DOI: 10.1111/bph.15009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 01/16/2020] [Accepted: 01/17/2020] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND AND PURPOSE P2X4 receptors are emerging therapeutic targets for treating chronic pain and cardiovascular disease. Dogs are well-recognised natural models of human disease, but information regarding P2X4 receptors in dogs is lacking. To aid the development and validation of P2X4 receptor ligands, we have characterised and compared canine and human P2X4 receptors. EXPERIMENTAL APPROACH Genomic DNA was extracted from whole blood samples from 101 randomly selected dogs and sequenced across the P2RX4 gene to identify potential missense variants. Recombinant canine and human P2X4 receptors tagged with Emerald GFP were expressed in 1321N1 and HEK293 cells and analysed by immunoblotting and confocal microscopy. In these cells, receptor pharmacology was characterised using nucleotide-induced Fura-2 AM measurements of intracellular Ca2+ and known P2X4 receptor antagonists. P2X4 receptor-mediated inward currents in HEK293 cells were assessed by automated patch clamp. KEY RESULTS No P2RX4 missense variants were identified in any canine samples. Canine and human P2X4 receptors were localised primarily to lysosomal compartments. ATP was the primary agonist of canine P2X4 receptors with near identical efficacy and potency at human receptors. 2'(3')-O-(4-benzoylbenzoyl)-ATP, but not ADP, was a partial agonist with reduced potency for canine P2X4 receptors compared to the human orthologues. Five antagonists inhibited canine P2X4 receptors, with 1-(2,6-dibromo-4-isopropyl-phenyl)-3-(3-pyridyl)urea displaying reduced sensitivity and potency at canine P2X4 receptors. CONCLUSION AND IMPLICATIONS P2X4 receptors are highly conserved across dog pedigrees and display expression patterns and pharmacological profiles similar to human receptors, supporting validation and use of therapeutic agents for P2X4 receptor-related disease onset and management in dogs and humans.
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Affiliation(s)
- Reece A Sophocleous
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | - Tracey Berg
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | - Rocio K Finol-Urdaneta
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia.,Electrophysiology Facility for Cell Phenotyping and Drug Discovery, Wollongong, NSW, Australia
| | - Vanessa Sluyter
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | - Shikara Keshiya
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | - Lachlan Bell
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | | | | | - Aine Seavers
- Oak Flats Veterinary Clinic, Oak Flats, NSW, Australia
| | - Rachael Bartlett
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | - Mark Dowton
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | - Leanne Stokes
- School of Pharmacy, University of East Anglia, Norwich, UK
| | - Lezanne Ooi
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | - Ronald Sluyter
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
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32
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Chen LJ. Genetic Association of Age-Related Macular Degeneration and Polypoidal Choroidal Vasculopathy. Asia Pac J Ophthalmol (Phila) 2020; 9:104-109. [PMID: 32195675 DOI: 10.1097/01.apo.0000656976.47696.7d] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV) are leading causes of irreversible blindness among the elderly population in developed countries. Although being considered as different subtypes of a same disease, neovascular AMD and PCV have differences in clinical, epidemiological, therapeutic, and genetic profiles. Both AMD and PCV are complex diseases involving multiple genetic and environmental risk factors. Different genetic strategies have been adopted to discover associated genes and variants for neovascular AMD and PCV, including genome-wide association study (GWAS), next-generation sequencing (NGS) based sequence analysis, and candidate gene analyses. So far, a number of susceptible genes have been identified for AMD and/or PCV, such as CFH, ARMS2-HTRA1, C2-CFB-SKIV2L, C3, CETP, and FGD6. Although many of these genes are shared by AMD and PCV, some showed difference between them, such as ARMS2-HTRA1 and FGD6. Also, some of the genes showed ethnic diversities, such as the CFH p.Tyr402His variant. Further larger-scale genomic studies should be warranted to identify more susceptibility genes for AMD and, in particular, PCV among different populations, and differentiate the genetic architectures between neovascular AMD and PCV.
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Affiliation(s)
- Li Jia Chen
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
- Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital Eye Center, Hong Kong, China
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Fletcher EL. Contribution of microglia and monocytes to the development and progression of age related macular degeneration. Ophthalmic Physiol Opt 2020; 40:128-139. [PMID: 32017190 DOI: 10.1111/opo.12671] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 12/10/2019] [Accepted: 01/03/2020] [Indexed: 12/12/2022]
Abstract
PURPOSE Age related macular degeneration (AMD) is the leading cause of irreversible vision loss in industrialised nations. Based on genetics, as well as proteome analysis of drusen, the role the innate immune system in the development and/or progression of the disease is well established. Mononuclear phagocytes, such as microglia and monocytes, play critical roles in innate immunity. Here, the role of retinal microglia in mediating normal retinal function, and how these cells change with age is discussed, so as to understand their role in the development and progression of AMD. RECENT FINDINGS It is now known that microglia dynamically survey the neural environment, responding rapidly to even the most subtle neural injury. The dynamic and phagocytic roles of microglia can change with age contributing to alteration in the response of these cells to damage with age. Accumulation of innate immune cells in the subretinal space is a hallmark feature of the development of AMD, reflecting either an increase in migration of monocytes into the retina, or a failure of immune cell elimination from the retina. Furthermore, changes in phagocytic ability of immune cells could contribute to the accumulation of drusen deposits in the posterior eye. SUMMARY An overview of how retinal microglia maintain retinal homeostasis under normal conditions is provided, and then how they contribute to each stage of AMD. In addition, circulating monocytes are altered in those with AMD, contributing to the overall inflammatory state. Understanding the role of cells of the innate immune system in AMD may uncover novel therapeutic targets with which to reduce either the development or progression of disease.
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Affiliation(s)
- Erica L Fletcher
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria, Australia
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Molecular Mechanisms of Calcium Signaling During Phagocytosis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1246:103-128. [PMID: 32399828 DOI: 10.1007/978-3-030-40406-2_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Calcium (Ca2+) is a ubiquitous second messenger involved in the regulation of numerous cellular functions including vesicular trafficking, cytoskeletal rearrangements and gene transcription. Both global as well as localized Ca2+ signals occur during phagocytosis, although their functional impact on the phagocytic process has been debated. After nearly 40 years of research, a consensus may now be reached that although not strictly required, Ca2+ signals render phagocytic ingestion and phagosome maturation more efficient, and their manipulation make an attractive avenue for therapeutic interventions. In the last decade many efforts have been made to identify the channels and regulators involved in generating and shaping phagocytic Ca2+ signals. While molecules involved in store-operated calcium entry (SOCE) of the STIM and ORAI family have taken center stage, members of the canonical, melastatin, mucolipin and vanilloid transient receptor potential (TRP), as well as purinergic P2X receptor families are now recognized to play significant roles. In this chapter, we review the recent literature on research that has linked specific Ca2+-permeable channels and regulators to phagocytic function. We highlight the fact that lipid mediators are emerging as important regulators of channel gating and that phagosomal ionic homeostasis and Ca2+ release also play essential parts. We predict that improved methodologies for measuring these factors will be critical for future advances in dissecting the intricate biology of this fascinating immune process.
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Kanellopoulos JM, Delarasse C. Pleiotropic Roles of P2X7 in the Central Nervous System. Front Cell Neurosci 2019; 13:401. [PMID: 31551714 PMCID: PMC6738027 DOI: 10.3389/fncel.2019.00401] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 08/19/2019] [Indexed: 12/16/2022] Open
Abstract
The purinergic receptor P2X7 is expressed in neural and immune cells known to be involved in neurological diseases. Its ligand, ATP, is a signaling molecule that can act as a neurotransmitter in physiological conditions or as a danger signal when released in high amount by damaged/dying cells or activated glial cells. Thus, ATP is a danger-associated molecular pattern. Binding of ATP by P2X7 leads to the activation of different biochemical pathways, depending on the physiological or pathological environment. The aim of this review is to discuss various functions of P2X7 in the immune and central nervous systems. We present evidence that P2X7 may have a detrimental or beneficial role in the nervous system, in the context of neurological pathologies: epilepsy, Alzheimer’s disease, multiple sclerosis, amyotrophic lateral sclerosis, age-related macular degeneration and cerebral artery occlusion.
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Affiliation(s)
| | - Cécile Delarasse
- Inserm, Sorbonne Université, CNRS, Institut de la Vision, Paris, France
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Laíns I, Chung W, Kelly RS, Gil J, Marques M, Barreto P, Murta JN, Kim IK, Vavvas DG, Miller JB, Silva R, Lasky-Su J, Liang L, Miller JW, Husain D. Human Plasma Metabolomics in Age-Related Macular Degeneration: Meta-Analysis of Two Cohorts. Metabolites 2019; 9:E127. [PMID: 31269701 PMCID: PMC6680405 DOI: 10.3390/metabo9070127] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 06/27/2019] [Accepted: 06/28/2019] [Indexed: 01/01/2023] Open
Abstract
The pathogenesis of age-related macular degeneration (AMD), a leading cause of blindness worldwide, remains only partially understood. This has led to the current lack of accessible and reliable biofluid biomarkers for diagnosis and prognosis, and absence of treatments for dry AMD. This study aimed to assess the plasma metabolomic profiles of AMD and its severity stages with the ultimate goal of contributing to addressing these needs. We recruited two cohorts: Boston, United States (n = 196) and Coimbra, Portugal (n = 295). Fasting blood samples were analyzed using ultra-high performance liquid chromatography mass spectrometry. For each cohort, we compared plasma metabolites of AMD patients versus controls (logistic regression), and across disease stages (permutation-based cumulative logistic regression considering both eyes). Meta-analyses were then used to combine results from the two cohorts. Our results revealed that 28 metabolites differed significantly between AMD patients versus controls (false discovery rate (FDR) q-value: 4.1 × 10-2-1.8 × 10-5), and 67 across disease stages (FDR q-value: 4.5 × 10-2-1.7 × 10-4). Pathway analysis showed significant enrichment of glycerophospholipid, purine, taurine and hypotaurine, and nitrogen metabolism (p-value ≤ 0.04). In conclusion, our findings support that AMD patients present distinct plasma metabolomic profiles, which vary with disease severity. This work contributes to the understanding of AMD pathophysiology, and can be the basis of future biomarkers and precision medicine for this blinding condition.
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Affiliation(s)
- Inês Laíns
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
- Faculty of Medicine, University of Coimbra, 3000 Coimbra, Portugal
- Centro Hospitalar e Universitário de Coimbra, 3000 Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image, 3000 Coimbra, Portugal
| | - Wonil Chung
- Program in Genetic Epidemiology and Statistical Genetics, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Rachel S Kelly
- Systems Genetics and Genomics Unit, Channing Division of Network Medicine Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - João Gil
- Faculty of Medicine, University of Coimbra, 3000 Coimbra, Portugal
| | - Marco Marques
- Faculty of Medicine, University of Coimbra, 3000 Coimbra, Portugal
| | - Patrícia Barreto
- Association for Innovation and Biomedical Research on Light and Image, 3000 Coimbra, Portugal
| | - Joaquim N Murta
- Faculty of Medicine, University of Coimbra, 3000 Coimbra, Portugal
- Centro Hospitalar e Universitário de Coimbra, 3000 Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image, 3000 Coimbra, Portugal
| | - Ivana K Kim
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
| | - Demetrios G Vavvas
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
| | - John B Miller
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
| | - Rufino Silva
- Faculty of Medicine, University of Coimbra, 3000 Coimbra, Portugal
- Centro Hospitalar e Universitário de Coimbra, 3000 Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image, 3000 Coimbra, Portugal
| | - Jessica Lasky-Su
- Systems Genetics and Genomics Unit, Channing Division of Network Medicine Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Liming Liang
- Program in Genetic Epidemiology and Statistical Genetics, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Joan W Miller
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
| | - Deeba Husain
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA.
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Fletcher EL, Wang AY, Jobling AI, Rutar MV, Greferath U, Gu B, Vessey KA. Targeting P2X7 receptors as a means for treating retinal disease. Drug Discov Today 2019; 24:1598-1605. [PMID: 30954685 DOI: 10.1016/j.drudis.2019.03.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 03/07/2019] [Accepted: 03/29/2019] [Indexed: 12/28/2022]
Abstract
Age-related macular degeneration and glaucoma are the commonest causes of irreversible vision loss in industrialized countries. The purine ATP is known to regulate a range of cellular functions in the retina via its action on P2 receptors, especially the P2X7 receptor. Although agents that attenuate P2X7 receptor function have been in development for many years, no compound is currently approved for the treatment of eye disease. However, newer compounds that cross the blood-brain barrier could have potential to reduce vision loss. This review will outline recent information relating to the role of P2X7 in age-related macular degeneration and glaucoma and, subsequently, we will discuss recent developments for attenuating P2X7 receptor function.
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Affiliation(s)
- Erica L Fletcher
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville 3010, Victoria, Australia.
| | - Anna Y Wang
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville 3010, Victoria, Australia
| | - Andrew I Jobling
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville 3010, Victoria, Australia
| | - Matthew V Rutar
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville 3010, Victoria, Australia
| | - Ursula Greferath
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville 3010, Victoria, Australia
| | - Ben Gu
- Florey Institute of Neuroscience and Mental Health, Parkville 3010, Victoria, Australia
| | - Kirstan A Vessey
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville 3010, Victoria, Australia
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38
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Zheng C, Ferrari D, Zhang M, Baird P. Ranking the importance of genetic factors by variable‐selection confidence sets. J R Stat Soc Ser C Appl Stat 2019. [DOI: 10.1111/rssc.12337] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
| | - Davide Ferrari
- University of Bozen–Bolzano Bolzano Italy
- University of Melbourne Melbourne Australia
| | - Michael Zhang
- University of Melbourne Melbourne Australia
- Royal Victorian Eye and Ear Hospital Melbourne Australia
| | - Paul Baird
- University of Melbourne Melbourne Australia
- Royal Victorian Eye and Ear Hospital Melbourne Australia
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Gu BJ, Wiley JS. P2X7 as a scavenger receptor for innate phagocytosis in the brain. Br J Pharmacol 2018; 175:4195-4208. [PMID: 30098011 DOI: 10.1111/bph.14470] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 07/20/2018] [Accepted: 07/25/2018] [Indexed: 12/29/2022] Open
Abstract
The P2X7 receptor has been widely studied for its ATP-induced pro-inflammatory effect, but in the absence of a ligand, P2X7 has a second function as a scavenger receptor, which is active in the development of the human brain. The scavenger activity of P2X7 is only evident in the absence of serum but is fully active in cerebrospinal fluid. P2X7 on the cell surface is present as a membrane complex, and an attachment to non-muscle myosin of the cytoskeleton is required for particle engulfment. Selective antagonists of P2X7 pro-inflammatory function have little effect on phagocytosis, but inheritance of a variant haplotype spanning the P2RX7 and P2RX4 genes has been associated with loss of P2X7-mediated phagocytosis. Recent studies in mice suggest that the innate phagocytosis mediated by P2X7 receptors declines with ageing. Thus, defective P2X7-mediated phagocytosis may contribute to age-related neuro-degenerative diseases including Alzheimer's disease, age-related macular degeneration and primary progressive multiple sclerosis.
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Affiliation(s)
- Ben J Gu
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia
| | - James S Wiley
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia
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40
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Leeson HC, Kasherman MA, Chan-Ling T, Lovelace MD, Brownlie JC, Toppinen KM, Gu BJ, Weible MW. P2X7 Receptors Regulate Phagocytosis and Proliferation in Adult Hippocampal and SVZ Neural Progenitor Cells: Implications for Inflammation in Neurogenesis. Stem Cells 2018; 36:1764-1777. [PMID: 30068016 PMCID: PMC6635745 DOI: 10.1002/stem.2894] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 07/04/2018] [Accepted: 07/06/2018] [Indexed: 12/26/2022]
Abstract
Identifying the signaling mechanisms that regulate adult neurogenesis is essential to understanding how the brain may respond to neuro‐inflammatory events. P2X7 receptors can regulate pro‐inflammatory responses, and in addition to their role as cation channels they can trigger cell death and mediate phagocytosis. How P2X7 receptors may regulate adult neurogenesis is currently unclear. Here, neural progenitor cells (NPCs) derived from adult murine hippocampal subgranular (SGZ) and cerebral subventricular (SVZ) zones were utilized to characterize the roles of P2X7 in adult neurogenesis, and assess the effects of high extracellular ATP, characteristic of inflammation, on NPCs. Immunocytochemistry found NPCs in vivo and in vitro expressed P2X7, and the activity of P2X7 in culture was demonstrated using calcium influx and pore formation assays. Live cell and confocal microscopy, in conjunction with flow cytometry, revealed P2X7+ NPCs were able to phagocytose fluorescent beads, and this was inhibited by ATP, indicative of P2X7 involvement. Furthermore, P2X7 receptors were activated with ATP or BzATP, and 5‐ethynyl‐2′‐deoxyuridine (EdU) used to observe a dose‐dependent decrease in NPC proliferation. A role for P2X7 in decreased NPC proliferation was confirmed using chemical inhibition and NPCs from P2X7−/− mice. Together, these data present three distinct roles for P2X7 during adult neurogenesis, depending on extracellular ATP concentrations: (a) P2X7 receptors can form transmembrane pores leading to cell death, (b) P2X7 receptors can regulate rates of proliferation, likely via calcium signaling, and (c) P2X7 can function as scavenger receptors in the absence of ATP, allowing NPCs to phagocytose apoptotic NPCs during neurogenesis. stem cells2018;36:1764–1777
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Affiliation(s)
- Hannah C Leeson
- Griffith Institute for Drug Discovery, Griffith University, Brisbane, Queensland, Australia
| | - Maria A Kasherman
- Griffith Institute for Drug Discovery, Griffith University, Brisbane, Queensland, Australia
| | - Tailoi Chan-Ling
- Discipline of Anatomy and Histology, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia.,Bosch Institute, The University of Sydney, Sydney, New South Wales, Australia
| | - Michael D Lovelace
- Discipline of Anatomy and Histology, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia.,Applied Neurosciences Program, Peter Duncan Neurosciences Research Unit, St. Vincent's Centre for Applied Medical Research, Sydney, New South Wales, Australia.,St. Vincent's Clinical School, University of New South Wales Medicine, UNSW, Sydney, Sydney, New South Wales, Australia
| | - Jeremy C Brownlie
- School of Environment and Science, Griffith University, Brisbane, Queensland, Australia
| | - Kelly M Toppinen
- Griffith Institute for Drug Discovery, Griffith University, Brisbane, Queensland, Australia
| | - Ben J Gu
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Michael W Weible
- Griffith Institute for Drug Discovery, Griffith University, Brisbane, Queensland, Australia.,Bosch Institute, The University of Sydney, Sydney, New South Wales, Australia.,School of Environment and Science, Griffith University, Brisbane, Queensland, Australia
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Layhadi JA, Turner J, Crossman D, Fountain SJ. ATP Evokes Ca 2+ Responses and CXCL5 Secretion via P2X 4 Receptor Activation in Human Monocyte-Derived Macrophages. THE JOURNAL OF IMMUNOLOGY 2017; 200:1159-1168. [PMID: 29255078 DOI: 10.4049/jimmunol.1700965] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 11/16/2017] [Indexed: 01/08/2023]
Abstract
Leukocytes sense extracellular ATP, a danger-associated molecular pattern, released during cellular stress and death, via activation of cell surface P2X and P2Y receptors. Here, we investigate P2 receptor expression in primary human monocyte-derived macrophages and receptors that mediate ATP-evoked intracellular [Ca2+]i signals and cytokine production in response to ATP concentrations that exclude P2X7 receptor activation. Expression of P2X1, P2X4, P2X5, P2X7, P2Y1, P2Y2, P2Y4, P2Y6, P2Y11, and P2Y13 was confirmed by quantitative RT-PCR and immunocytochemistry. ATP elicited intracellular Ca2+ responses in a concentration-dependent fashion (EC50 = 11.4 ± 2.9 μM, n = 3). P2Y11 and P2Y13 activations mediated the amplitude of [Ca2+]i response, whereas P2X4 activation, but not P2X1 or P2X7, determined the duration of Ca2+ response during a sustained phase. ATP mediated gene induction of CXCL5, a proinflammatory chemokine. P2X4 antagonism (PSB-12062 or BX430) inhibited ATP-mediated induction of CXCL5 gene expression and secretion of CXCL5 by primary macrophage. Inhibition of CXCL5 secretion by P2X4 antagonists was lost in the absence of extracellular Ca2+ Reciprocally, positive allosteric modulation of P2X4 (ivermectin) augmented ATP-mediated CXCL5 secretion. P2X7, P2Y11, or P2Y13 receptor did not contribute to CXCL5 secretion. Together, the data reveals a role for P2X4 in determining the duration of ATP-evoked Ca2+ responses and CXCL5 secretion in human primary macrophage.
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Affiliation(s)
- Janice A Layhadi
- School of Biological Sciences, University of East Anglia, Norwich, Norfolk NR4 7TJ, United Kingdom
| | - Jeremy Turner
- Elsie Bertram Diabetes Centre, Norfolk and Norwich University Hospital, Norwich NR4 7UY, United Kingdom; and
| | - David Crossman
- School of Medicine, University of St Andrews, St Andrews KY16 9TF, United Kingdom
| | - Samuel J Fountain
- School of Biological Sciences, University of East Anglia, Norwich, Norfolk NR4 7TJ, United Kingdom;
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2016 Glenn A. Fry Award Lecture: Mechanisms and Potential Treatments of Early Age-Related Macular Degeneration. Optom Vis Sci 2017; 94:939-945. [DOI: 10.1097/opx.0000000000001124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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Neuronal P2X7 Receptors Revisited: Do They Really Exist? J Neurosci 2017; 37:7049-7062. [PMID: 28747388 DOI: 10.1523/jneurosci.3103-16.2017] [Citation(s) in RCA: 123] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 05/22/2017] [Accepted: 05/24/2017] [Indexed: 12/13/2022] Open
Abstract
P2X7 receptors (Rs) constitute a subclass of ATP-sensitive ionotropic receptors (P2X1-P2X7). P2X7Rs have many distinguishing features, mostly based on their long intracellular C terminus regulating trafficking to the cell membrane, protein-protein interactions, and post-translational modification. Their C-terminal tail is especially important in enabling the transition from the nonselective ion channel mode to a membrane pore allowing the passage of large molecules. There is an ongoing dispute on the existence of neuronal P2X7Rs with consequences for our knowledge on their involvement in neuroinflammation, aggravating stroke, temporal lobe epilepsy, neuropathic pain, and various neurodegenerative diseases. Whereas early results appeared to support the operation of P2X7Rs at neurons, more recently glial P2X7Rs are increasingly considered as indirect causes of neuronal effects. Specific tools for P2X7Rs are of limited value because of the poor selectivity of agonists, and the inherent failure of antibodies to differentiate between the large number of active and inactive splice variants, or gain-of-function and loss-of-function small nucleotide polymorphisms of the receptor. Unfortunately, the available P2RX7 knock-out mice generated by pharmaceutical companies possess certain splice variants, which evade inactivation. In view of the recently discovered bidirectional dialogue between astrocytes and neurons (and even microglia and neurons), we offer an alternative explanation for previous data, which assumedly support the existence of P2X7Rs at neurons. We think that the unbiased reader will follow our argumentation on astrocytic or microglial P2X7Rs being the primary targets of pathologically high extracellular ATP concentrations, although a neuronal localization of these receptors cannot be fully excluded either.
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Vessey KA, Gu BJ, Jobling AI, Phipps JA, Greferath U, Tran MX, Dixon MA, Baird PN, Guymer RH, Wiley JS, Fletcher EL. Loss of Function of P2X7 Receptor Scavenger Activity in Aging Mice: A Novel Model for Investigating the Early Pathogenesis of Age-Related Macular Degeneration. THE AMERICAN JOURNAL OF PATHOLOGY 2017. [PMID: 28628761 DOI: 10.1016/j.ajpath.2017.04.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Age-related macular degeneration (AMD) is a leading cause of irreversible, severe vision loss in Western countries. Recently, we identified a novel pathway involving P2X7 receptor scavenger function expressed on ocular immune cells as a risk factor for advanced AMD. In this study, we investigate the effect of loss of P2X7 receptor function on retinal structure and function during aging. P2X7-null and wild-type C57bl6J mice were investigated at 4, 12, and 18 months of age for macrophage phagocytosis activity, ocular histological changes, and retinal function. Phagocytosis activity of blood-borne macrophages decreased with age at 18 months in the wild-type mouse. Lack of P2X7 receptor function reduced phagocytosis at all ages compared to wild-type mice. At 12 months of age, P2X7-null mice had thickening of Bruchs membrane and retinal pigment epithelium dysfunction. By 18 months of age, P2X7-null mice displayed phenotypic characteristics consistent with early AMD, including Bruchs membrane thickening, retinal pigment epithelium cell loss, retinal functional deficits, and signs of subretinal inflammation. Our present study shows that loss of function of the P2X7 receptor in mice induces retinal changes representing characteristics of early AMD, providing a valuable model for investigating the role of scavenger receptor function and the immune system in the development of this age-related disease.
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Affiliation(s)
- Kirstan A Vessey
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
| | - Ben J Gu
- Florey Institute of Neuroscience, Melbourne, Victoria, Australia
| | - Andrew I Jobling
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
| | - Joanna A Phipps
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
| | - Ursula Greferath
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
| | - Mai X Tran
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
| | - Michael A Dixon
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
| | - Paul N Baird
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia; Division of Ophthalmology, Department of Surgery, The University of Melbourne, Melbourne, Victoria, Australia
| | - Robyn H Guymer
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia; Division of Ophthalmology, Department of Surgery, The University of Melbourne, Melbourne, Victoria, Australia
| | - James S Wiley
- Florey Institute of Neuroscience, Melbourne, Victoria, Australia
| | - Erica L Fletcher
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia.
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Targeting the P2X7 Receptor in Age-Related Macular Degeneration. Vision (Basel) 2017; 1:vision1020011. [PMID: 31740637 PMCID: PMC6836166 DOI: 10.3390/vision1020011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 03/30/2017] [Accepted: 03/30/2017] [Indexed: 01/07/2023] Open
Abstract
The P2X7 receptor (P2X7R) is a membrane receptor for the extracellular adenosine triphosphate (ATP). It functions as a ligand-gated non-selective cation channel and can mediate formation of a large non-selective membrane pore. Activation of the P2X7R induces multiple downstream events, including oxidative stress, inflammatory responses and cell death. Although the P2X7R has been identified in the retinal pigment epithelium (RPE) and different layers of retina, its biological and pathological functions as well as its downstream signaling pathways in the RPE and retina are not yet fully understood. Better understanding of the function of P2X7R in the RPE and retina under normal and disease states might lead to novel therapeutic targets in retinal diseases, including age-related macular degeneration (AMD). This brief review will mainly focus on recent findings on in vitro and in vivo evidence for the role of the P2X7R in the RPE and AMD.
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Abstract
The P2X7 receptor is a trimeric ion channel gated by extracellular adenosine 5'-triphosphate. The receptor is present on an increasing number of different cells types including stem, blood, glial, neural, ocular, bone, dental, exocrine, endothelial, muscle, renal and skin cells. The P2X7 receptor induces various downstream events in a cell-specific manner, including inflammatory molecule release, cell proliferation and death, metabolic events, and phagocytosis. As such this receptor plays important roles in heath and disease. Increasing knowledge about the P2X7 receptor has been gained from studies of, but not limited to, protein chemistry including cloning, site-directed mutagenesis, crystal structures and atomic modeling, as well as from studies of primary tissues and transgenic mice. This chapter focuses on the P2X7 receptor itself. This includes the P2RX7 gene and its products including splice and polymorphic variants. This chapter also reviews modulators of P2X7 receptor activation and inhibition, as well as the transcriptional regulation of the P2RX7 gene via its promoter and enhancer regions, and by microRNA and long-coding RNA. Furthermore, this chapter discusses the post-translational modification of the P2X7 receptor by N-linked glycosylation, adenosine 5'-diphosphate ribosylation and palmitoylation. Finally, this chapter reviews interaction partners of the P2X7 receptor, and its cellular localisation and trafficking within cells.
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Affiliation(s)
- Ronald Sluyter
- School of Biological Sciences, University of Wollongong, Wollongong, NSW, 2522, Australia. .,Centre for Medical and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia. .,Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia.
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47
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Ho T, Aplin FP, Jobling AI, Phipps JA, de Iongh RU, Greferath U, Vessey KA, Fletcher EL. Localization and Possible Function of P2X Receptors in Normal and Diseased Retinae. J Ocul Pharmacol Ther 2016; 32:509-517. [DOI: 10.1089/jop.2015.0158] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Tracy Ho
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Australia
| | - Felix P. Aplin
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Australia
| | - Andrew I. Jobling
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Australia
| | - Joanna A. Phipps
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Australia
| | - Robb U. de Iongh
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Australia
| | - Ursula Greferath
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Australia
| | - Kirstan A. Vessey
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Australia
| | - Erica L. Fletcher
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Australia
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48
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Gu BJ, Huang X, Ou A, Rembach A, Fowler C, Avula PK, Horton A, Doecke JD, Villemagne VL, Macaulay SL, Maruff P, Fletcher EL, Guymer R, Wiley JS, Masters CL. Innate phagocytosis by peripheral blood monocytes is altered in Alzheimer's disease. Acta Neuropathol 2016; 132:377-89. [PMID: 27411339 DOI: 10.1007/s00401-016-1596-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 06/27/2016] [Accepted: 07/05/2016] [Indexed: 11/30/2022]
Abstract
Sporadic Alzheimer's disease (AD) is characterised by the deposition and accumulation of specific protein aggregates. Failure of clearance could underlie this process, and recent genetic association studies point towards involvement of the phagocytosis and autophagy pathways. We developed a real-time tri-color flow cytometry method to quantitate the phagocytic function of human peripheral blood monocyte subsets including non-classic CD14(dim)CD16(+), intermediate CD14(+)CD16(+) and classic CD14(+)CD16(-) monocytes. Using this method, we have measured the phagocytic ability of fresh monocytes in a study of preclinical, prodromal and clinical AD, matched with cognitively normal healthy control subjects. Basal levels of phagocytosis in all three subsets of monocytes were similar between healthy controls and AD patients, while a significant increase of basal phagocytosis was found in subjects with high Aβ-amyloid burden as assessed by PET scans. Pre-treating cells with Copaxone (CPX, to stimulate phagocytosis) or ATP (an inhibitor of P2X7-mediated phagocytosis) showed a differential response depending on clinical or Aβ-burden status, indicating a relative functional deficit. Overall the results are consistent with a perturbation of basal and stimulated innate phagocytosis in sporadic AD.
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Affiliation(s)
- Ben J Gu
- The Florey Institute of Neuroscience & Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, VIC, 3052, Australia.
| | - Xin Huang
- The Florey Institute of Neuroscience & Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, VIC, 3052, Australia
| | - Amber Ou
- The Florey Institute of Neuroscience & Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, VIC, 3052, Australia
| | - Alan Rembach
- The Florey Institute of Neuroscience & Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, VIC, 3052, Australia
| | - Christopher Fowler
- The Florey Institute of Neuroscience & Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, VIC, 3052, Australia
| | - Pavan K Avula
- The Florey Institute of Neuroscience & Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, VIC, 3052, Australia
| | - Adam Horton
- The Florey Institute of Neuroscience & Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, VIC, 3052, Australia
| | - James D Doecke
- CSIRO Health and Biosecurity/Australian E-Health Research Centre, Herston, QLD, 4029, Australia
| | - Victor L Villemagne
- The Florey Institute of Neuroscience & Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, VIC, 3052, Australia
- Department of Nuclear Medicine and Centre for PET, Austin Health, Heidelberg, VIC, 3084, Australia
| | | | - Paul Maruff
- The Florey Institute of Neuroscience & Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, VIC, 3052, Australia
- Cogstate Pty Ltd, Melbourne, VIC, 3000, Australia
| | - Erica L Fletcher
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Robyn Guymer
- Centre for Eye Research Australia Royal Victorian Eye and Ear Hospital, The University of Melbourne, East Melbourne, VIC, 3002, Australia
| | - James S Wiley
- The Florey Institute of Neuroscience & Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, VIC, 3052, Australia
| | - Colin L Masters
- The Florey Institute of Neuroscience & Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, VIC, 3052, Australia
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Wakx A, Dutot M, Massicot F, Mascarelli F, Limb GA, Rat P. Amyloid β Peptide Induces Apoptosis Through P2X7 Cell Death Receptor in Retinal Cells: Modulation by Marine Omega-3 Fatty Acid DHA and EPA. Appl Biochem Biotechnol 2016; 178:368-81. [PMID: 26467741 PMCID: PMC4718936 DOI: 10.1007/s12010-015-1878-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 09/28/2015] [Indexed: 11/25/2022]
Abstract
Retinal Müller glial cells have already been implicated in age-related macular degeneration (AMD). AMD is characterized by accumulation of toxic amyloid-β peptide (Aβ); the question we raise is as follows: is P2X7 receptor, known to play an important role in several degenerative diseases, involved in Aβ toxicity on Müller cells? Retinal Müller glial cells were incubated with Aβ for 48 h. Cell viability was assessed using the alamarBlue assay and cytotoxicity using the lactate dehydrogenase (LDH) release assay. P2X7 receptor expression was highlighted by immunolabeling observed on confocal microscopy and its activation was evaluated by YO-PRO-1 assay. Hoechst 33342 was used to evaluate chromatin condensation, and caspases 8 and 3 activation was assessed using AMC assays. Lipid formulation rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) used in Age-Related Eye Disease Study 2 was incubated on cells for 15 min prior to Aβ incubation. For the first time, we showed that Aβ induced caspase-independent apoptosis through P2X7 receptor activation on our retinal model. DHA and EPA are polyunsaturated fatty acids recommended in food supplement to prevent AMD. We therefore modulated Aβ cytotoxicity using a lipid formulation rich in DHA and EPA to have a better understanding of the results observed in clinical studies. We showed that fish oil rich in EPA and DHA, in combination with a potent P2X7 receptor antagonist, represents an efficient modulator of Aβ toxicity and that P2X7 could be an interesting therapeutic target to prevent AMD.
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Affiliation(s)
- Anaïs Wakx
- />UMR CNRS 8638—Chimie-Toxicologie Analytique et Cellulaire, Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes, 4 avenue de l’Observatoire, 75006 Paris, France
- />Inserm U598, Physiopathologie des maladies oculaires, Innovations thérapeutiques, Centre de Recherches Biomédicales des Cordeliers, 75270 Paris Cedex 06, France
| | - Mélody Dutot
- />UMR CNRS 8638—Chimie-Toxicologie Analytique et Cellulaire, Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes, 4 avenue de l’Observatoire, 75006 Paris, France
- />Laboratoire Yslab, 2 rue Félix Le Dantec, 29000 Quimper, France
- />Inserm U598, Physiopathologie des maladies oculaires, Innovations thérapeutiques, Centre de Recherches Biomédicales des Cordeliers, 75270 Paris Cedex 06, France
| | - France Massicot
- />UMR CNRS 8638—Chimie-Toxicologie Analytique et Cellulaire, Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes, 4 avenue de l’Observatoire, 75006 Paris, France
- />Inserm U598, Physiopathologie des maladies oculaires, Innovations thérapeutiques, Centre de Recherches Biomédicales des Cordeliers, 75270 Paris Cedex 06, France
| | - Frédéric Mascarelli
- />INSERM U 872—Physiopathologie des maladies oculaires: Innovations thérapeutiques, Centre de Recherches des Cordeliers, 15 Rue de l’Ecole de Médecine, 75006 Paris, France
- />Inserm U598, Physiopathologie des maladies oculaires, Innovations thérapeutiques, Centre de Recherches Biomédicales des Cordeliers, 75270 Paris Cedex 06, France
| | - G. Astrid Limb
- />Division of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology and Moorfields Eye Hospital, 11 Bath Street, London, EC1V 9EL UK
| | - Patrice Rat
- />UMR CNRS 8638—Chimie-Toxicologie Analytique et Cellulaire, Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes, 4 avenue de l’Observatoire, 75006 Paris, France
- />Inserm U598, Physiopathologie des maladies oculaires, Innovations thérapeutiques, Centre de Recherches Biomédicales des Cordeliers, 75270 Paris Cedex 06, France
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50
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Stebbing MJ, Cottee JM, Rana I. The Role of Ion Channels in Microglial Activation and Proliferation - A Complex Interplay between Ligand-Gated Ion Channels, K(+) Channels, and Intracellular Ca(2.). Front Immunol 2015; 6:497. [PMID: 26557116 PMCID: PMC4617059 DOI: 10.3389/fimmu.2015.00497] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Accepted: 09/14/2015] [Indexed: 12/17/2022] Open
Abstract
Microglia are often referred to as the immune cells of the brain. They are most definitely involved in immune responses to invading pathogens and inflammatory responses to tissue damage. However, recent results suggest microglia are vital for normal functioning of the brain. Neuroinflammation, as well as more subtle changes, in microglial function has been implicated in the pathogenesis of many brain diseases and disorders. Upon sensing alterations in their local environment, microglia change their shape and release factors that can modify the excitability of surrounding neurons. During neuroinflammation, microglia proliferate and release NO, reactive oxygen species, cytokines and chemokines. If inflammation resolves then their numbers normalize again via apoptosis. Microglia express a wide array of ion channels and different types are implicated in all of the cellular processes listed above. Modulation of microglial ion channels has shown great promise as a therapeutic strategy in several brain disorders. In this review, we discuss recent advances in our knowledge of microglial ion channels and their roles in responses of microglia to changes in the extracellular milieu.
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Affiliation(s)
- Martin James Stebbing
- Health Innovations Research Institute and School of Medical Sciences, RMIT University , Bundoora, VIC , Australia
| | - Jennifer Marie Cottee
- Health Innovations Research Institute and School of Medical Sciences, RMIT University , Bundoora, VIC , Australia
| | - Indrajeetsinh Rana
- Health Innovations Research Institute and School of Medical Sciences, RMIT University , Bundoora, VIC , Australia ; School of Health Sciences, Federation University Australia , Ballarat, VIC , Australia
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