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Hou L, Zhou X, Zhang C, Wang K, Liu X, Che Y, Sun F, Li H, Wang Q, Zhang D, Hong JS. NADPH oxidase-derived H 2O 2 mediates the regulatory effects of microglia on astrogliosis in experimental models of Parkinson's disease. Redox Biol 2017; 12:162-170. [PMID: 28237879 PMCID: PMC5328707 DOI: 10.1016/j.redox.2017.02.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 02/12/2017] [Accepted: 02/21/2017] [Indexed: 12/17/2022] Open
Abstract
Astrogliosis has long been recognized in Parkinson's disease (PD), the most common neurodegenerative movement disorder. However, the mechanisms of how astroglia become activated remain unclear. Reciprocal interactions between microglia and astroglia play a pivotal role in regulating the activities of astroglia. The purpose of this study is to investigate the mechanism by which microglia regulate astrogliosis by using lipopolysaccharide (LPS) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse PD models. We found that the activation of microglia preceded astroglia in the substantia nigra of mice treated with either LPS or MPTP. Furthermore, suppression of microglial activation by pharmacological inhibition or genetic deletion of NADPH oxidase (NOX2) in mice attenuated astrogliosis. The important role of NOX2 in microglial regulation of astrogliosis was further mirrored in a mixed-glia culture system. Mechanistically, H2O2, a product of microglial NOX2 activation, serves as a direct signal to regulate astrogliosis. Astrogliosis was induced by H2O2 through a process in which extracellularly generated H2O2 diffused into the cytoplasm and subsequently stimulated activation of transcription factors, STAT1 and STAT3. STAT1/3 activation regulated the immunological functions of H2O2-induced astrogliosis since AG490, an inhibitor of STAT1/3, attenuated the gene expressions of both proinflammatory and neurotrophic factors in H2O2-treated astrocyte. Our findings indicate that microglial NOX2-generated H2O2 is able to regulate the immunological functions of astroglia via a STAT1/3-dependent manner, providing additional evidence for the immune pathogenesis and therapeutic studies of PD. Microglia are capable of regulating the immunological functions of astrogliosis in Parkinson's disease. NADPH oxidase-derived H2O2 is recognized as a paracrine signal for microglial regulation of astrogliosis. Transcription factors STAT1 and STAT3 play pivotal roles in H2O2-induced astroglial activation.
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Affiliation(s)
- Liyan Hou
- Department of Occupational and Environmental Health, School of Public Health, Dalian Medical University, No. 9 W. Lvshun South Road, Dalian 116044, China
| | - Xueying Zhou
- Department of Occupational and Environmental Health, School of Public Health, Dalian Medical University, No. 9 W. Lvshun South Road, Dalian 116044, China
| | - Cong Zhang
- Department of Nutrition and Food Hygiene, School of Public Health, Dalian Medical University, No. 9 W. Lvshun South Road, Dalian 116044, China
| | - Ke Wang
- Department of Nutrition, Second Hospital, Dalian Medical University, Dalian 116023, China
| | - Xiaofang Liu
- Department of Nutrition and Food Hygiene, School of Public Health, Dalian Medical University, No. 9 W. Lvshun South Road, Dalian 116044, China
| | - Yuning Che
- Department of Occupational and Environmental Health, School of Public Health, Dalian Medical University, No. 9 W. Lvshun South Road, Dalian 116044, China
| | - Fuqiang Sun
- Department of Occupational and Environmental Health, School of Public Health, Dalian Medical University, No. 9 W. Lvshun South Road, Dalian 116044, China
| | - Huihua Li
- Department of Nutrition and Food Hygiene, School of Public Health, Dalian Medical University, No. 9 W. Lvshun South Road, Dalian 116044, China
| | - Qingshan Wang
- Department of Occupational and Environmental Health, School of Public Health, Dalian Medical University, No. 9 W. Lvshun South Road, Dalian 116044, China.
| | - Dan Zhang
- State Key Laboratory of Natural Products and Functions, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Jau-Shyong Hong
- Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
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102
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Wong YC, Krainc D. α-synuclein toxicity in neurodegeneration: mechanism and therapeutic strategies. Nat Med 2017; 23:1-13. [PMID: 28170377 PMCID: PMC8480197 DOI: 10.1038/nm.4269] [Citation(s) in RCA: 580] [Impact Index Per Article: 82.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 12/14/2016] [Indexed: 12/13/2022]
Abstract
Alterations in α-synuclein dosage lead to familial Parkinson's disease (PD), and its accumulation results in synucleinopathies that include PD, dementia with Lewy bodies (DLB) and multiple system atrophy (MSA). Furthermore, α-synuclein contributes to the fibrilization of amyloid-b and tau, two key proteins in Alzheimer's disease, which suggests a central role for α-synuclein toxicity in neurodegeneration. Recent studies of factors contributing to α-synuclein toxicity and its disruption of downstream cellular pathways have expanded our understanding of disease pathogenesis in synucleinopathies. In this Review, we discuss these emerging themes, including the contributions of aging, selective vulnerability and non-cell-autonomous factors such as α-synuclein cell-to-cell propagation and neuroinflammation. Finally, we summarize recent efforts toward the development of targeted therapies for PD and related synucleinopathies.
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Affiliation(s)
- Yvette C Wong
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Dimitri Krainc
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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103
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Qiao H, He X, Zhang Q, Zhang N, Li L, Hui Y, Li W, Wang D, Wu Z. Α-synuclein induces microglial cell migration through stimulating HIF-1α accumulation. J Neurosci Res 2017; 95:1809-1817. [PMID: 28134982 DOI: 10.1002/jnr.24012] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Revised: 11/28/2016] [Accepted: 12/12/2016] [Indexed: 01/09/2023]
Affiliation(s)
- Hongfei Qiao
- Departments of Rehabilitation Medicine; the Second Affiliated Hospital of Xi’an Jiaotong University; Xi’an China
| | - Xijing He
- Departments of Orthopedics; the Second Affiliated Hospital of Xi’an Jiaotong University; Xi’an China
| | - Qiaojun Zhang
- Departments of Rehabilitation Medicine; the Second Affiliated Hospital of Xi’an Jiaotong University; Xi’an China
| | - Ni Zhang
- Departments of Rehabilitation Medicine; the Second Affiliated Hospital of Xi’an Jiaotong University; Xi’an China
| | - Libo Li
- Departments of Rehabilitation Medicine; the Second Affiliated Hospital of Xi’an Jiaotong University; Xi’an China
| | - Yanping Hui
- Departments of Rehabilitation Medicine; the Second Affiliated Hospital of Xi’an Jiaotong University; Xi’an China
| | - Wenjuan Li
- Departments of Rehabilitation Medicine; the Second Affiliated Hospital of Xi’an Jiaotong University; Xi’an China
| | - Dong Wang
- Departments of Orthopedics; the Second Affiliated Hospital of Xi’an Jiaotong University; Xi’an China
| | - Zhonghen Wu
- Departments of Rehabilitation Medicine; the Second Affiliated Hospital of Xi’an Jiaotong University; Xi’an China
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104
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Borland H, Vilhardt F. Prelysosomal Compartments in the Unconventional Secretion of Amyloidogenic Seeds. Int J Mol Sci 2017; 18:ijms18010227. [PMID: 28124989 PMCID: PMC5297856 DOI: 10.3390/ijms18010227] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 01/09/2017] [Accepted: 01/16/2017] [Indexed: 12/18/2022] Open
Abstract
A mechanistic link between neuron-to-neuron transmission of secreted amyloid and propagation of protein malconformation cytopathology and disease has recently been uncovered in animal models. An enormous interest in the unconventional secretion of amyloids from neurons has followed. Amphisomes and late endosomes are the penultimate maturation products of the autophagosomal and endosomal pathways, respectively, and normally fuse with lysosomes for degradation. However, under conditions of perturbed membrane trafficking and/or lysosomal deficiency, prelysosomal compartments may instead fuse with the plasma membrane to release any contained amyloid. After a brief introduction to the endosomal and autophagosomal pathways, we discuss the evidence for autophagosomal secretion (exophagy) of amyloids, with a comparative emphasis on Aβ1-42 and α-synuclein, as luminal and cytosolic amyloids, respectively. The ESCRT-mediated import of cytosolic amyloid into late endosomal exosomes, a known vehicle of transmission of macromolecules between cells, is also reviewed. Finally, mechanisms of lysosomal dysfunction, deficiency, and exocytosis are exemplified in the context of genetically identified risk factors, mainly for Parkinson's disease. Exocytosis of prelysosomal or lysosomal organelles is a last resort for clearance of cytotoxic material and alleviates cytopathy. However, they also represent a vehicle for the concentration, posttranslational modification, and secretion of amyloid seeds.
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Affiliation(s)
- Helena Borland
- Department of Neurodegeneration In Vitro, H. Lundbeck A/S, 2500 Valby, Denmark.
| | - Frederik Vilhardt
- Department of Cellular and Molecular Medicine, Panum Institute, University of Copenhagen, 2200N Copenhagen, Denmark.
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105
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Defects in trafficking bridge Parkinson's disease pathology and genetics. Nature 2016; 539:207-216. [PMID: 27830778 DOI: 10.1038/nature20414] [Citation(s) in RCA: 326] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 09/02/2016] [Indexed: 12/13/2022]
Abstract
Parkinson's disease is a debilitating, age-associated movement disorder. A central aspect of the pathophysiology of Parkinson's disease is the progressive demise of midbrain dopamine neurons and their axonal projections, but the underlying causes of this loss are unclear. Advances in genetics and experimental model systems have illuminated an important role for defects in intracellular transport pathways to lysosomes. The accumulation of altered proteins and damaged mitochondria, particularly at axon terminals, ultimately might overwhelm the capacity of intracellular disposal mechanisms. Cell-extrinsic mechanisms, including inflammation and prion-like spreading, are proposed to have both protective and deleterious functions in Parkinson's disease.
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106
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Impairment of PDGF-induced chemotaxis by extracellular α-synuclein through selective inhibition of Rac1 activation. Sci Rep 2016; 6:37810. [PMID: 27886249 PMCID: PMC5122898 DOI: 10.1038/srep37810] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 11/02/2016] [Indexed: 01/10/2023] Open
Abstract
Parkinson’s disease (PD) is characterized by α-synuclein (α-Syn)-positive intracytoplasmic inclusions, known as Lewy bodies. Although it is known that extracellular α-Syn is detected in the plasma and cerebrospinal fluid, its physiological significance remains unclear. Here, we show that extracellular α-Syn suppresses platelet-derived growth factor (PDGF)-induced chemotaxis in human neuroblastoma SH-SY5Y cells. The inhibitory effect was stronger in the mutant α-Syn(A53T), found in hereditary PD, and the degree of inhibition was time-dependent, presumably because of the oligomerization of α-Syn. PDGF-induced activation of Akt or Erk was not influenced by α-Syn(A53T). Further studies revealed that α-Syn(A53T) inhibited PDGF-induced Rac1 activation, whereas Cdc42 activation remained unaffected, resulting in unbalanced actin filament remodeling. These results shed light on the understanding of pathological as well as physiological functions of extracellular α-Syn in neuronal cells.
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107
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Zhang QS, Heng Y, Yuan YH, Chen NH. Pathological α-synuclein exacerbates the progression of Parkinson's disease through microglial activation. Toxicol Lett 2016; 265:30-37. [PMID: 27865851 DOI: 10.1016/j.toxlet.2016.11.002] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 11/02/2016] [Accepted: 11/06/2016] [Indexed: 01/15/2023]
Abstract
Parkinson's disease (PD) is characterized by α-synuclein accumulation, dopaminergic neuron loss and inflammation. α-Synuclein can be secreted by neurons and activate microglia to different degrees. Excessive microglial activation can increase the production of tumor necrosis factor alpha (TNF-α), interleukin-1-β (IL-1β), interleukin-6 (IL-6), interferon-γ (INF-γ), inducible nitric oxide synthase (iNOS), reactive oxygen species (ROS) and nitric oxide (NO), and can also enhance microglial phagocytosis and migration as well as lymphocyte infiltration. Pathological α-synuclein and microglial activation can potentiate each other, leading to the loss of dopaminergic neurons and accelerated PD degeneration. This review will mainly describe the profiles of α-synuclein-activated microglia, with particular emphasis on the signaling cascades involved in this process.
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Affiliation(s)
- Qiu-Shuang Zhang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Yang Heng
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Yu-He Yuan
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Nai-Hong Chen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China; Hunan University of Chinese Medicine, Changsha, 410208, China.
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108
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Fernandes JTS, Chutna O, Chu V, Conde JP, Outeiro TF. A Novel Microfluidic Cell Co-culture Platform for the Study of the Molecular Mechanisms of Parkinson's Disease and Other Synucleinopathies. Front Neurosci 2016; 10:511. [PMID: 27895548 PMCID: PMC5108800 DOI: 10.3389/fnins.2016.00511] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 10/25/2016] [Indexed: 01/09/2023] Open
Abstract
Although, the precise molecular mechanisms underlying Parkinson's disease (PD) are still elusive, it is now known that spreading of alpha-synuclein (aSyn) pathology and neuroinflammation are important players in disease progression. Here, we developed a novel microfluidic cell-culture platform for studying the communication between two different cell populations, a process of critical importance not only in PD but also in many biological processes. The integration of micro-valves in the device enabled us to control fluid routing, cellular microenvironments, and to simulate paracrine signaling. As proof of concept, two sets of experiments were designed to show how this platform can be used to investigate specific molecular mechanisms associated with PD. In one experiment, naïve H4 neuroglioma cells were co-cultured with cells expressing aSyn tagged with GFP (aSyn-GFP), to study the release and spreading of the protein. In our experimental set up, we induced the release of the contents of aSyn-GFP producing cells to the medium and monitored the protein's diffusion. In another experiment, H4 cells were co-cultured with N9 microglial cells to assess the interplay between two cell lines in response to environmental stimuli. Here, we observed an increase in the levels of reactive oxygen species in H4 cells cultured in the presence of activated N9 cells, confirming the cross talk between different cell populations. In summary, the platform developed in this study affords novel opportunities for the study of the molecular mechanisms involved in PD and other neurodegenerative diseases.
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Affiliation(s)
- João T S Fernandes
- Instituto de Engenharia de Sistemas E Computadores (INESC) - Microsistemas e Nanotecnologias and Institute of Nanoscience and Nanotechnology Lisbon, Portugal
| | - Oldriska Chutna
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa Lisbon, Portugal
| | - Virginia Chu
- Instituto de Engenharia de Sistemas E Computadores (INESC) - Microsistemas e Nanotecnologias and Institute of Nanoscience and Nanotechnology Lisbon, Portugal
| | - João P Conde
- Instituto de Engenharia de Sistemas E Computadores (INESC) - Microsistemas e Nanotecnologias and Institute of Nanoscience and NanotechnologyLisbon, Portugal; Departamento de Bioengenharia, Instituto Superior Técnico, Universidade de LisboaLisbon, Portugal
| | - Tiago F Outeiro
- Faculdade de Ciências Médicas, CEDOC - Chronic Diseases Research Center, Universidade Nova de LisboaLisbon, Portugal; Department of Neurodegeneration and Restorative Research, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center GöttingenGöttingen, Germany
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109
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Kustrimovic N, Rasini E, Legnaro M, Bombelli R, Aleksic I, Blandini F, Comi C, Mauri M, Minafra B, Riboldazzi G, Sanchez-Guajardo V, Marino F, Cosentino M. Dopaminergic Receptors on CD4+ T Naive and Memory Lymphocytes Correlate with Motor Impairment in Patients with Parkinson's Disease. Sci Rep 2016; 6:33738. [PMID: 27652978 PMCID: PMC5031979 DOI: 10.1038/srep33738] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Accepted: 09/02/2016] [Indexed: 01/11/2023] Open
Abstract
Parkinson’s disease (PD) is characterized by loss of dopaminergic neurons in substantia nigra pars compacta, α-synuclein (α-syn)-rich intraneuronal inclusions (Lewy bodies), and microglial activation. Emerging evidence suggests that CD4+ T lymphocytes contribute to neuroinflammation in PD. Since the mainstay of PD treatment is dopaminergic substitution therapy and dopamine is an established transmitter connecting nervous and immune systems, we examined CD4+ T naive and memory lymphocytes in PD patients and in healthy subjects (HS), with specific regard to dopaminergic receptor (DR) expression. In addition, the in vitro effects of α-syn were assessed on CD4+ T naive and memory cells. Results showed extensive association between DR expression in T lymphocytes and motor dysfunction, as assessed by UPDRS Part III score. In total and CD4+ T naive cells expression of D1-like DR decrease, while in T memory cells D2-like DR increase with increasing score. In vitro, α-syn increased CD4+ T memory cells, possibly to a different extent in PD patients and in HS, and affected DR expression with cell subset-specific patterns. The present results support the involvement of peripheral adaptive immunity in PD, and may contribute to develop novel immunotherapies for PD, as well as to better use of current dopaminergic antiparkinson drugs.
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Affiliation(s)
- Natasa Kustrimovic
- Center of Research in Medical Pharmacology, University of Insubria, Varese, Italy
| | - Emanuela Rasini
- Center of Research in Medical Pharmacology, University of Insubria, Varese, Italy
| | - Massimiliano Legnaro
- Center of Research in Medical Pharmacology, University of Insubria, Varese, Italy
| | - Raffaella Bombelli
- Center of Research in Medical Pharmacology, University of Insubria, Varese, Italy
| | - Iva Aleksic
- Center of Research in Medical Pharmacology, University of Insubria, Varese, Italy
| | - Fabio Blandini
- Center for Research in Neurodegenerative Diseases, "C. Mondino", National Neurological Institute, Pavia, Italy
| | - Cristoforo Comi
- Movement Disorders Centre, Neurology Unit, Department of Translational Medicine, University of Piemonte Orientale, Novara, Italy
| | - Marco Mauri
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
| | - Brigida Minafra
- Center for Research in Neurodegenerative Diseases, "C. Mondino", National Neurological Institute, Pavia, Italy
| | - Giulio Riboldazzi
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
| | - Vanesa Sanchez-Guajardo
- Neuroimmunology of Degenerative Diseases group and AUidias pilot-center NEURODIN, department of Biomedicine, HEALTH, Aarhus University, Aarhus, Denmark
| | - Franca Marino
- Center of Research in Medical Pharmacology, University of Insubria, Varese, Italy
| | - Marco Cosentino
- Center of Research in Medical Pharmacology, University of Insubria, Varese, Italy
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110
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Le W, Wu J, Tang Y. Protective Microglia and Their Regulation in Parkinson's Disease. Front Mol Neurosci 2016; 9:89. [PMID: 27708561 PMCID: PMC5030290 DOI: 10.3389/fnmol.2016.00089] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Accepted: 09/07/2016] [Indexed: 01/09/2023] Open
Abstract
Microglia-mediated neuroinflammation is a hallmark of Parkinson’s disease (PD). In the brains of patients with PD, microglia have both neurotoxic and neuroprotective effects, depending on their activation state. In this review, we focus on recent research demonstrating the neuroprotective role of microglia in PD. Accumulating evidence indicates that the protective mechanisms of microglia may result from their regulation of transrepression pathways via nuclear receptors, anti-inflammatory responses, neuron–microglia crosstalk, histone modification, and microRNA regulation. All of these mechanisms work together to suppress the production of neurotoxic inflammatory components. However, during the progression of PD, the detrimental effects of inflammation overpower the protective actions of microglia. Therefore, an in-depth exploration of the mechanisms underlying microglial neuroprotection, and a means of promoting the transformation of microglia to the protective phenotype, are urgently needed for the treatment of PD.
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Affiliation(s)
- Weidong Le
- Center for Clinical Research on Neurological Diseases, First Affiliated Hospital, Dalian Medical University, Dalian China
| | - Junjiao Wu
- Department of Rheumatology and Immunology, Xiangya Hospital of Central South University, ChangshaChina; Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TXUSA
| | - Yu Tang
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TXUSA; Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TXUSA
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111
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Patel C, Xu Z, Shosha E, Xing J, Lucas R, Caldwell RW, Caldwell RB, Narayanan SP. Treatment with polyamine oxidase inhibitor reduces microglial activation and limits vascular injury in ischemic retinopathy. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1862:1628-39. [PMID: 27239699 PMCID: PMC5091072 DOI: 10.1016/j.bbadis.2016.05.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 04/26/2016] [Accepted: 05/26/2016] [Indexed: 12/15/2022]
Abstract
Retinal vascular injury is a major cause of vision impairment in ischemic retinopathies. Insults such as hyperoxia, oxidative stress and inflammation contribute to this pathology. Previously, we showed that hyperoxia-induced retinal neurodegeneration is associated with increased polyamine oxidation. Here, we are studying the involvement of polyamine oxidases in hyperoxia-induced injury and death of retinal vascular endothelial cells. New-born C57BL6/J mice were exposed to hyperoxia (70% O2) from postnatal day (P) 7 to 12 and were treated with the polyamine oxidase inhibitor MDL 72527 or vehicle starting at P6. Mice were sacrificed after different durations of hyperoxia and their retinas were analyzed to determine the effects on vascular injury, microglial cell activation, and inflammatory cytokine profiling. The results of this analysis showed that MDL 72527 treatment significantly reduced hyperoxia-induced retinal vascular injury and enhanced vascular sprouting as compared with the vehicle controls. These protective effects were correlated with significant decreases in microglial activation as well as levels of inflammatory cytokines and chemokines. In order to model the effects of polyamine oxidation in causing microglial activation in vitro, studies were performed using rat brain microvascular endothelial cells treated with conditioned-medium from rat retinal microglia stimulated with hydrogen peroxide. Conditioned-medium from activated microglial cultures induced cell stress signals and cell death in microvascular endothelial cells. These studies demonstrate the involvement of polyamine oxidases in hyperoxia-induced retinal vascular injury and retinal inflammation in ischemic retinopathy, through mechanisms involving cross-talk between endothelial cells and resident retinal microglia.
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Affiliation(s)
- C Patel
- Vision Discovery Institute, Augusta University, Augusta, GA 30912, USA; Vascular Biology Center, Augusta University, Augusta, GA 30912, USA; Department of Occupational Therapy, College of Allied Health Sciences, Augusta University, Augusta, GA 30912, USA.
| | - Z Xu
- Vision Discovery Institute, Augusta University, Augusta, GA 30912, USA; Vascular Biology Center, Augusta University, Augusta, GA 30912, USA.
| | - E Shosha
- Vision Discovery Institute, Augusta University, Augusta, GA 30912, USA; Vascular Biology Center, Augusta University, Augusta, GA 30912, USA; Charlie Norwood VA Medical Center, Augusta, GA, USA.
| | - J Xing
- Vision Discovery Institute, Augusta University, Augusta, GA 30912, USA; Vascular Biology Center, Augusta University, Augusta, GA 30912, USA.
| | - R Lucas
- Vascular Biology Center, Augusta University, Augusta, GA 30912, USA; Department of Pharmacology & Toxicology, Augusta University, Augusta, GA 30912, USA.
| | - R W Caldwell
- Department of Pharmacology & Toxicology, Augusta University, Augusta, GA 30912, USA.
| | - R B Caldwell
- Vision Discovery Institute, Augusta University, Augusta, GA 30912, USA; Vascular Biology Center, Augusta University, Augusta, GA 30912, USA; Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA 30912, USA; Charlie Norwood VA Medical Center, Augusta, GA, USA.
| | - S P Narayanan
- Vision Discovery Institute, Augusta University, Augusta, GA 30912, USA; Vascular Biology Center, Augusta University, Augusta, GA 30912, USA; Department of Occupational Therapy, College of Allied Health Sciences, Augusta University, Augusta, GA 30912, USA.
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112
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Wang S, Chu CH, Guo M, Jiang L, Nie H, Zhang W, Wilson B, Yang L, Stewart T, Hong JS, Zhang J. Identification of a specific α-synuclein peptide (α-Syn 29-40) capable of eliciting microglial superoxide production to damage dopaminergic neurons. J Neuroinflammation 2016; 13:158. [PMID: 27329107 PMCID: PMC4915166 DOI: 10.1186/s12974-016-0606-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 06/01/2016] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Misfolded α-synuclein (α-Syn) aggregates participate in the pathogenesis of synucleinopathies, such as Parkinson's disease. Whereas much is known about how the various domains within full-length α-Syn (FL-α-Syn) contribute to the formation of α-Syn aggregates and therefore to their neurotoxicity, little is known about whether the individual peptides that can be generated from α-syn, possibly as intermediate metabolites during degradation of misfolded α-Syn aggregates, are neurotoxic themselves. METHODS A series of synthesized α-Syn peptides, corresponding to the locus in FL-α-Syn containing alanine 30, substitution of which with a proline causes a familial form of Parkinson's disease, were examined for their capacity of inducing release of microglial superoxide. The neurotoxicity of these peptides was measured according to their influence on the ability of neuroglial cultures deficient in gp91 (phox) , the catalytic unit of NADPH oxidase (Nox2), or wild-type cultures to take up (3)H-labeled dopamine and on the number of tyrosine hydroxylase-staining-positive neurons. Western blots and confocal images were utilized to analyze membrane translocation of p47 (phox) and p67 (phox) , phosphorylation of p47 (phox) and Erk1/2 kinase, and binding of α-Syn peptides to gp91 (phox) . Activation of brain microglia in mice injected with α-Syn peptides was demonstrated by immunostaining for major histocompatibility complex (MHC)-II along with qPCR for Iba-1 and MHC-II. RESULTS We report α-Syn (29-40) as a specific peptide capable of activating microglial Nox2 to produce superoxide and cause dopaminergic neuronal damage. Administered to mice, this peptide also activated brain microglia to increase expression of MHC-II and Iba-1 and stimulated oxidation reaction. Exploring the underlying mechanisms showed that α-Syn (29-40) peptide triggered Nox2 to generate extracellular superoxide and its metabolite H2O2 by binding to the catalytic unit gp91 (phox) of Nox2; diffusing into cytosol, H2O2 activated Erk1/2 kinase to phosphorylate p47 (phox) and p67 (phox) and further activated Nox2, establishing a positive feedback loop to amplify the Nox2-mediated response. CONCLUSIONS Collectively, our study suggests novel information regarding how α-Syn causes neuronal injury, possibly including mechanisms involving abnormal metabolites of α-Syn aggregates.
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Affiliation(s)
- Shijun Wang
- Department of Pathology, University of Washington School of Medicine, Seattle, Washington, 98104, USA.,Neuropharmacology Section, Laboratory of Neurobiology, National Institute of Environmental Health Sciences National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - Chun-Hsien Chu
- Neuropharmacology Section, Laboratory of Neurobiology, National Institute of Environmental Health Sciences National Institutes of Health, Research Triangle Park, NC, 27709, USA.,Institute of Molecular Medicine, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Mingri Guo
- Neuropharmacology Section, Laboratory of Neurobiology, National Institute of Environmental Health Sciences National Institutes of Health, Research Triangle Park, NC, 27709, USA.,Department of Laboratory Medicine, Tianjin Haihe Hospital, Tianjin Institute of Respiratory Diseases, Tianjin Medical University, Tianjin, 300350, China
| | - Lulu Jiang
- Neuropharmacology Section, Laboratory of Neurobiology, National Institute of Environmental Health Sciences National Institutes of Health, Research Triangle Park, NC, 27709, USA.,Institute of Toxicology, School of Public Health, Shandong University, Jinan, Shandong, 250012, China
| | - Hui Nie
- Neuropharmacology Section, Laboratory of Neurobiology, National Institute of Environmental Health Sciences National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - Wei Zhang
- Department of Geriatrics, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100050, China
| | - Belinda Wilson
- Neuropharmacology Section, Laboratory of Neurobiology, National Institute of Environmental Health Sciences National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - Li Yang
- Department of Pathology, University of Washington School of Medicine, Seattle, Washington, 98104, USA
| | - Tessandra Stewart
- Department of Pathology, University of Washington School of Medicine, Seattle, Washington, 98104, USA
| | - Jau-Shyong Hong
- Neuropharmacology Section, Laboratory of Neurobiology, National Institute of Environmental Health Sciences National Institutes of Health, Research Triangle Park, NC, 27709, USA.
| | - Jing Zhang
- Department of Pathology, University of Washington School of Medicine, Seattle, Washington, 98104, USA. .,Department of Pathology, Peking University Health Science Center, Beijing, 100083, China.
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113
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Christensen DP, Ejlerskov P, Rasmussen I, Vilhardt F. Reciprocal signals between microglia and neurons regulate α-synuclein secretion by exophagy through a neuronal cJUN-N-terminal kinase-signaling axis. J Neuroinflammation 2016; 13:59. [PMID: 26957005 PMCID: PMC4782388 DOI: 10.1186/s12974-016-0519-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 02/22/2016] [Indexed: 11/23/2022] Open
Abstract
Background Secretion of proteopathic α-synuclein (α-SNC) species from neurons is a suspected driving force in the propagation of Parkinson’s disease (PD). We have previously implicated exophagy, the exocytosis of autophagosomes, as a dominant mechanism of α-SNC secretion in differentiated PC12 or SH-SY5Y nerve cells. Here we have examined the regulation of exophagy associated with different forms of nerve cell stress relevant to PD. Results We identify cJUN-N-terminal kinase (JNK) activity as pivotal in the secretory fate of autophagosomes containing α-SNC. Pharmacological inhibition or genetic (shRNA) knockdown of JNK2 or JNK3 decreases α-SNC secretion in differentiated PC12 and SH-SY5Y cells, respectively. Conversely, expression of constitutively active mitogen-activated protein kinase kinase 7 (MKK7)-JNK2 and -JNK3 constructs augment secretion. The transcriptional activity of cJUN was not required for the observed effects. We establish a causal relationship between increased α-SNC release by exophagy and JNK activation subsequent to lysosomal fusion deficiency (overexpression of Lewy body-localized protein p25α or bafilomycin A1). JNK activation following neuronal ER or oxidative stress was not correlated with exophagy, but of note, we demonstrate that reciprocal signaling between microglia and neurons modulates α-SNC secretion. NADPH oxidase activity of microglia cell lines was upregulated by direct co-culture with α-SNC-expressing PC12 neurons or by passive transfer of nerve cell-conditioned medium. Conversely, inflammatory factors secreted from activated microglia increased JNK activation and α-SNC secretion several-fold in PC12 cells. While we do not identify these factors, we extend our observations by showing that exposure of neurons in monoculture to TNFα, a classical pro-inflammatory mediator of activated microglia, is sufficient to increase α-SNC secretion in a mechanism dependent on JNK2 or JNK3. In continuation hereof, we show that also IFNβ and TGFβ increase the release of α-SNC from PC12 neurons. Conclusions We implicate stress kinases of the JNK family in the regulation of exophagy and release of α-SNC following endogenous or exogenous stimulation. In a wider scope, our results imply that microglia not only inflict bystander damage to neurons in late phases of inflammatory brain disease but may also be active mediators of disease propagation.
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Affiliation(s)
- Dan Ploug Christensen
- Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, 3C Blegdamsvej, 2200, Copenhagen N, Denmark.
| | - Patrick Ejlerskov
- Biotech Research and Innovation Centre, University of Copenhagen, Ole Maaløes Vej 5, 2200, Copenhagen N, Denmark.
| | - Izabela Rasmussen
- Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, 3C Blegdamsvej, 2200, Copenhagen N, Denmark.
| | - Frederik Vilhardt
- Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, 3C Blegdamsvej, 2200, Copenhagen N, Denmark.
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114
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Zheng J, Wang M, Wei W, Keller JN, Adhikari B, King JF, King ML, Peng N, Laine RA. Dietary Plant Lectins Appear to Be Transported from the Gut to Gain Access to and Alter Dopaminergic Neurons of Caenorhabditis elegans, a Potential Etiology of Parkinson's Disease. Front Nutr 2016; 3:7. [PMID: 27014695 PMCID: PMC4780318 DOI: 10.3389/fnut.2016.00007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Accepted: 02/15/2016] [Indexed: 11/13/2022] Open
Abstract
Lectins from dietary plants have been shown to enhance drug absorption in the gastrointestinal tract of rats, be transported trans-synaptically as shown by tracing of axonal and dendritic paths, and enhance gene delivery. Other carbohydrate-binding protein toxins are known to traverse the gut intact in dogs. Post-feeding rhodamine- or TRITC-tagged dietary lectins, the lectins were tracked from gut to dopaminergic neurons (DAergic-N) in transgenic Caenorhabditis elegans (C. elegans) [egIs1(Pdat-1:GFP)] where the mutant has the green fluorescent protein (GFP) gene fused to a dopamine transport protein gene labeling DAergic-N. The lectins were supplemented along with the food organism Escherichia coli (OP50). Among nine tested rhodamine/TRITC-tagged lectins, four, including Phaseolus vulgaris erythroagglutinin (PHA-E), Bandeiraea simplicifolia (BS-I), Dolichos biflorus agglutinin (DBA), and Arachis hypogaea agglutinin (PNA), appeared to be transported from gut to the GFP-DAergic-N. Griffonia Simplicifolia and PHA-E, reduced the number of GFP-DAergic-N, suggesting a toxic activity. PHA-E, BS-I, Pisum sativum (PSA), and Triticum vulgaris agglutinin (Succinylated) reduced fluorescent intensity of GFP-DAergic-N. PHA-E, PSA, Concanavalin A, and Triticum vulgaris agglutinin decreased the size of GFP-DAergic-N, while BS-I increased neuron size. These observations suggest that dietary plant lectins are transported to and affect DAergic-N in C. elegans, which support Braak and Hawkes' hypothesis, suggesting one alternate potential dietary etiology of Parkinson's disease (PD). A recent Danish study showed that vagotomy resulted in 40% lower incidence of PD over 20 years. Differences in inherited sugar structures of gut and neuronal cell surfaces may make some individuals more susceptible in this conceptual disease etiology model.
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Affiliation(s)
- Jolene Zheng
- School of Nutrition and Food Sciences, Louisiana State University, Baton Rouge, LA, USA
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA
| | - Mingming Wang
- School of Nutrition and Food Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - Wenqian Wei
- Department of Veterinary Science, College of Agriculture, Louisiana State University, Baton Rouge, LA, USA
- School of Life Sciences, Fudan University, Shanghai, China
| | - Jeffrey N. Keller
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA
| | - Binita Adhikari
- Nicholls State University, Thibodaux, LA, USA
- Louisiana Biomedical Research Network (LBRN) Summer Research Program (2010), Baton Rouge, LA, USA
| | - Jason F. King
- Department of Biological Sciences, Louisiana State University and A&M College, Baton Rouge, LA, USA
- Department of Chemistry, Louisiana State University and A&M College, Baton Rouge, LA, USA
| | - Michael L. King
- Department of Biological Sciences, Louisiana State University and A&M College, Baton Rouge, LA, USA
- Department of Chemistry, Louisiana State University and A&M College, Baton Rouge, LA, USA
| | - Nan Peng
- School of Life Sciences, Fudan University, Shanghai, China
| | - Roger A. Laine
- Department of Biological Sciences, Louisiana State University and A&M College, Baton Rouge, LA, USA
- Department of Chemistry, Louisiana State University and A&M College, Baton Rouge, LA, USA
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115
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Dudvarski Stankovic N, Teodorczyk M, Ploen R, Zipp F, Schmidt MHH. Microglia-blood vessel interactions: a double-edged sword in brain pathologies. Acta Neuropathol 2016; 131:347-63. [PMID: 26711460 DOI: 10.1007/s00401-015-1524-y] [Citation(s) in RCA: 194] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 11/09/2015] [Accepted: 12/12/2015] [Indexed: 12/12/2022]
Abstract
Microglia are long-living resident immune cells of the brain, which secure a stable chemical and physical microenvironment necessary for the proper functioning of the central nervous system (CNS). These highly dynamic cells continuously scan their environment for pathogens and possess the ability to react to damage-induced signals in order to protect the brain. Microglia, together with endothelial cells (ECs), pericytes and astrocytes, form the functional blood-brain barrier (BBB), a specialized endothelial structure that selectively separates the sensitive brain parenchyma from blood circulation. Microglia are in bidirectional and permanent communication with ECs and their perivascular localization enables them to survey the influx of blood-borne components into the CNS. Furthermore, they may stimulate the opening of the BBB, extravasation of leukocytes and angiogenesis. However, microglia functioning requires tight control as their dysregulation is implicated in the initiation and progression of numerous neurological diseases. Disruption of the BBB, changes in blood flow, introduction of pathogens in the sensitive CNS niche, insufficient nutrient supply, and abnormal secretion of cytokines or expression of endothelial receptors are reported to prime and attract microglia. Such reactive microglia have been reported to even escalate the damage of the brain parenchyma as is the case in ischemic injuries, brain tumors, multiple sclerosis, Alzheimer's and Parkinson's disease. In this review, we present the current state of the art of the causes and mechanisms of pathological interactions between microglia and blood vessels and explore the possibilities of targeting those dysfunctional interactions for the development of future therapeutics.
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Affiliation(s)
- Nevenka Dudvarski Stankovic
- Molecular Signal Transduction Laboratories, Institute for Microscopic Anatomy and Neurobiology, Focus Program Translational Neuroscience (FTN), Rhine Main Neuroscience Network (rmn²), University Medical Center of the Johannes Gutenberg University, Langenbeckstr. 1, 55131, Mainz, Germany.
- German Cancer Consortium (DKTK), Heidelberg, Germany.
- German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Marcin Teodorczyk
- Molecular Signal Transduction Laboratories, Institute for Microscopic Anatomy and Neurobiology, Focus Program Translational Neuroscience (FTN), Rhine Main Neuroscience Network (rmn²), University Medical Center of the Johannes Gutenberg University, Langenbeckstr. 1, 55131, Mainz, Germany.
| | - Robert Ploen
- Department of Neurology, Focus Program Translational Neuroscience (FTN) and Research Center for Immunotherapy (FZI), Rhine Main Neuroscience Network (rmn²), University Medical Center of the Johannes Gutenberg University, Mainz, Germany.
| | - Frauke Zipp
- Department of Neurology, Focus Program Translational Neuroscience (FTN) and Research Center for Immunotherapy (FZI), Rhine Main Neuroscience Network (rmn²), University Medical Center of the Johannes Gutenberg University, Mainz, Germany.
| | - Mirko H H Schmidt
- Molecular Signal Transduction Laboratories, Institute for Microscopic Anatomy and Neurobiology, Focus Program Translational Neuroscience (FTN), Rhine Main Neuroscience Network (rmn²), University Medical Center of the Johannes Gutenberg University, Langenbeckstr. 1, 55131, Mainz, Germany.
- German Cancer Consortium (DKTK), Heidelberg, Germany.
- German Cancer Research Center (DKFZ), Heidelberg, Germany.
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116
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Haslund-Vinding J, McBean G, Jaquet V, Vilhardt F. NADPH oxidases in oxidant production by microglia: activating receptors, pharmacology and association with disease. Br J Pharmacol 2016; 174:1733-1749. [PMID: 26750203 DOI: 10.1111/bph.13425] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Revised: 12/15/2015] [Accepted: 01/07/2016] [Indexed: 12/26/2022] Open
Abstract
Microglia are the resident immune cells of the CNS and constitute a self-sustaining population of CNS-adapted tissue macrophages. As mononuclear phagocytic cells, they express high levels of superoxide-producing NADPH oxidases (NOX). The sole function of the members of the NOX family is to generate reactive oxygen species (ROS) that are believed to be important in CNS host defence and in the redox signalling circuits that shape the different activation phenotypes of microglia. NOX are also important in pathological conditions, where over-generation of ROS contributes to neuronal loss via direct oxidative tissue damage or disruption of redox signalling circuits. In this review, we assess the evidence for involvement of NOX in CNS physiopathology, with particular emphasis on the most important surface receptors that lead to generation of NOX-derived ROS. We evaluate the potential significance of the subcellular distribution of NOX isoforms for redox signalling or release of ROS to the extracellular medium. Inhibitory mechanisms that have been reported to restrain NOX activity in microglia and macrophages in vivo are also discussed. We provide a critical appraisal of frequently used and recently developed NOX inhibitors. Finally, we review the recent literature on NOX and other sources of ROS that are involved in activation of the inflammasome and discuss the potential influence of microglia-derived oxidants on neurogenesis, neural differentiation and culling of surplus progenitor cells. The degree to which excessive, badly timed or misplaced NOX activation in microglia may affect neuronal homeostasis in physiological or pathological conditions certainly merits further investigation. LINKED ARTICLES This article is part of a themed section on Redox Biology and Oxidative Stress in Health and Disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.12/issuetoc.
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Affiliation(s)
- J Haslund-Vinding
- Institute of Cellular and Molecular Medicine, Copenhagen University, Copenhagen, Denmark.,Department of Pathology and Immunology, Centre Médical Universitaire, Geneva, Switzerland
| | - G McBean
- UCD School of Biomolecular and Biomedical Science, University College Dublin, Ireland
| | - V Jaquet
- Department of Pathology and Immunology, Centre Médical Universitaire, Geneva, Switzerland
| | - F Vilhardt
- Institute of Cellular and Molecular Medicine, Copenhagen University, Copenhagen, Denmark
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117
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Chen SH, Oyarzabal EA, Hong JS. Critical role of the Mac1/NOX2 pathway in mediating reactive microgliosis-generated chronic neuroinflammation and progressive neurodegeneration. Curr Opin Pharmacol 2015; 26:54-60. [PMID: 26498406 DOI: 10.1016/j.coph.2015.10.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 10/01/2015] [Accepted: 10/02/2015] [Indexed: 02/07/2023]
Abstract
As average life expectancy rises throughout the world, neurodegenerative diseases have emerged as one of the greatest global public heath challenges in modern times. Substantial efforts have been made in researching neurodegenerative diseases over the last few decades, yet their predominantly sporadic nature has made uncovering their etiologies challenging. Mounting evidence has suggested that factors like damage-associated molecular patterns (DAMPs) released by stressed and dying neurons are likely involved in disease pathology and in stimulating chronic activation of microglia that contributes to neuronal oxidative stress and degeneration. This review focuses on how the microglial integrin receptor Mac1 and its downstream effector NADPH oxidase (NOX2) contribute to maintaining chronic neuroinflammation and are crucial in inflammation-driven neurotoxicity in neurodegenerative diseases. Our hope is to provide new insights on novel targets and therapies that could slow or even halt neurodegeneration.
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Affiliation(s)
- Shih-Heng Chen
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA.
| | - Esteban A Oyarzabal
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA; Neurobiology Curriculum, University of North Carolina Chapel Hill, Chapel Hill, NC, USA
| | - Jau-Shyong Hong
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
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118
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Luna E, Luk KC. Bent out of shape: α-Synuclein misfolding and the convergence of pathogenic pathways in Parkinson's disease. FEBS Lett 2015; 589:3749-59. [PMID: 26505673 DOI: 10.1016/j.febslet.2015.10.023] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 10/15/2015] [Accepted: 10/18/2015] [Indexed: 02/03/2023]
Abstract
Protein inclusions made up primarily of misfolded α-synuclein (α-Syn) are the hallmark of a set of disorders known as synucleinopathies, most notably Parkinson's disease (PD). It is becoming increasingly appreciated that α-Syn misfolding can spread to anatomically connected regions in a prion-like manner. The protein aggregates that ensue are correlated with neurodegeneration in the various yet select neuronal populations that are affected. Recent advances have begun to shed light on the spreading and toxicity mechanisms that may be occurring in PD. Several key emerging themes are arising from this work suggesting that α-Syn mediated neurodegeneration is due to a combination of relative α-Syn expression level, connectivity to affected brain regions, and intrinsic vulnerability to pathology.
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Affiliation(s)
- Esteban Luna
- Center for Neurodegenerative Disease Research, Department of Pathology and Laboratory Medicine, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, United States
| | - Kelvin C Luk
- Center for Neurodegenerative Disease Research, Department of Pathology and Laboratory Medicine, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, United States.
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119
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Surendranathan A, Rowe JB, O'Brien JT. Neuroinflammation in Lewy body dementia. Parkinsonism Relat Disord 2015; 21:1398-406. [PMID: 26493111 DOI: 10.1016/j.parkreldis.2015.10.009] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 09/25/2015] [Accepted: 10/05/2015] [Indexed: 01/03/2023]
Abstract
Neuroinflammation is increasingly recognized as a key factor in the pathogenesis of neurodegenerative conditions. However, it remains unclear whether it has a protective or damaging role. Studies of Alzheimer's disease and Parkinson's disease have provided much of the evidence for inflammatory pathology in neurodegeneration. Here we review the evidence for inflammation in dementia with Lewy bodies and Parkinson's disease dementia. Neuroinflammation has been confirmed in vivo using PET imaging, with microglial activation seen in Parkinson's disease dementia and recently in dementia with Lewy bodies. In Parkinson's disease and Parkinson's disease dementia, microglial activation suggests a chronic inflammatory process, although there is also evidence of its association with cognitive ability and neuronal function. Alpha-synuclein in various conformations has also been linked to activation of microglia, with a broad range of components of the innate and adaptive immune systems associated with this interaction. Evidence of neuroinflammation in Lewy body dementia is further supported by pathological and biomarker studies. Genetic and epidemiological studies support a role for inflammation in Parkinson's disease, but have yet to provide the same for Lewy body dementia. This review highlights the need to identify whether the nature and extent of microglial activation in Lewy body dementia can be linked to structural change, progression of domain specific cognitive symptoms and peripheral inflammation as a marker of central microglial pathology. Answers to these questions will enable the evaluation of immunotherapies as potential therapeutic options for prevention or treatment of dementia with Lewy bodies and Parkinson's disease dementia.
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Affiliation(s)
| | - James B Rowe
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - John T O'Brien
- Department of Psychiatry, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
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