701
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Wiseman FK, Al-Janabi T, Hardy J, Karmiloff-Smith A, Nizetic D, Tybulewicz VLJ, Fisher EMC, Strydom A. A genetic cause of Alzheimer disease: mechanistic insights from Down syndrome. Nat Rev Neurosci 2015; 16:564-74. [PMID: 26243569 PMCID: PMC4678594 DOI: 10.1038/nrn3983] [Citation(s) in RCA: 337] [Impact Index Per Article: 37.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Down syndrome, which arises in individuals carrying an extra copy of chromosome 21, is associated with a greatly increased risk of early-onset Alzheimer disease. It is thought that this risk is conferred by the presence of three copies of the gene encoding amyloid precursor protein (APP)--an Alzheimer disease risk factor--although the possession of extra copies of other chromosome 21 genes may also play a part. Further study of the mechanisms underlying the development of Alzheimer disease in people with Down syndrome could provide insights into the mechanisms that cause dementia in the general population.
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Affiliation(s)
- Frances K Wiseman
- Department of Neurodegenerative Disease, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | - Tamara Al-Janabi
- Division of Psychiatry, University College London, Maple House, 149 Tottenham Court Road, London W1T 7NF, UK
| | - John Hardy
- Department of Molecular Neuroscience, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | - Annette Karmiloff-Smith
- Centre for Brain and Cognitive Development, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
| | - Dean Nizetic
- Lee Kong Chian School of Medicine, Nanyang Technological University, Novena Campus, 11 Mandalay Road, Singapore 308232; and the Blizard Institute, Barts and the London School of Medicine, Queen Mary University of London, 4 Newark Street, London E1 2AT, UK
| | | | - Elizabeth M C Fisher
- Department of Neurodegenerative Disease, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | - André Strydom
- Division of Psychiatry, University College London, Maple House, 149 Tottenham Court Road, London W1T 7NF, UK
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702
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Synapse-specific IL-1 receptor subunit reconfiguration augments vulnerability to IL-1β in the aged hippocampus. Proc Natl Acad Sci U S A 2015; 112:E5078-87. [PMID: 26305968 DOI: 10.1073/pnas.1514486112] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In the aged brain, synaptic plasticity and memory show increased vulnerability to impairment by the inflammatory cytokine interleukin 1β (IL-1β). In this study, we evaluated the possibility that synapses may directly undergo maladaptive changes with age that augment sensitivity to IL-1β impairment. In hippocampal neuronal cultures, IL-1β increased the expression of the IL-1 receptor type 1 and the accessory coreceptor AcP (proinflammatory), but not of the AcPb (prosurvival) subunit, a reconfiguration that potentiates the responsiveness of neurons to IL-1β. To evaluate whether synapses develop a similar heightened sensitivity to IL-1β with age, we used an assay to track long-term potentiation (LTP) in synaptosomes. We found that IL-1β impairs LTP directly at the synapse and that sensitivity to IL-1β is augmented in aged hippocampal synapses. The increased synaptic sensitivity to IL-1β was due to IL-1 receptor subunit reconfiguration, characterized by a shift in the AcP/AcPb ratio, paralleling our culture data. We suggest that the age-related increase in brain IL-1β levels drives a shift in IL-1 receptor configuration, thus heightening the sensitivity to IL-1β. Accordingly, selective blocking of AcP-dependent signaling with Toll-IL-1 receptor domain peptidomimetics prevented IL-1β-mediated LTP suppression and blocked the memory impairment induced in aged mice by peripheral immune challenge (bacterial lipopolysaccharide). Overall, this study demonstrates that increased AcP signaling, specifically at the synapse, underlies the augmented vulnerability to cognitive impairment by IL-1β that occurs with age.
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703
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Duffy CM, Yuan C, Wisdorf LE, Billington CJ, Kotz CM, Nixon JP, Butterick TA. Role of orexin A signaling in dietary palmitic acid-activated microglial cells. Neurosci Lett 2015; 606:140-4. [PMID: 26306651 DOI: 10.1016/j.neulet.2015.08.033] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 08/05/2015] [Accepted: 08/19/2015] [Indexed: 12/23/2022]
Abstract
Excess dietary saturated fatty acids such as palmitic acid (PA) induce peripheral and hypothalamic inflammation. Hypothalamic inflammation, mediated in part by microglial activation, contributes to metabolic dysregulation. In rodents, high fat diet-induced microglial activation results in nuclear translocation of nuclear factor-kappa B (NFκB), and increased central pro-inflammatory cytokines tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6). The hypothalamic neuropeptide orexin A (OXA, hypocretin 1) is neuroprotective in brain. In cortex, OXA can also reduce inflammation and neurodegeneration through a microglial-mediated pathway. Whether hypothalamic orexin neuroprotection mechanisms depend upon microglia is unknown. To address this issue, we evaluated effects of OXA and PA on inflammatory response in immortalized murine microglial and hypothalamic neuronal cell lines. We demonstrate for the first time in microglial cells that exposure to PA increases gene expression of orexin-1 receptor but not orexin-2 receptor. Pro-inflammatory markers IL-6, TNF-α, and inducible nitric oxide synthase in microglial cells are increased following PA exposure, but are reduced by pretreatment with OXA. The anti-inflammatory marker arginase-1 is increased by OXA. Finally, we show hypothalamic neurons exposed to conditioned media from PA-challenged microglia have increased cell survival only when microglia were pretreated with OXA. These data support the concept that OXA may act as an immunomodulatory regulator of microglia, reducing pro-inflammatory cytokines and increasing anti-inflammatory factors to promote a favorable neuronal microenvironment.
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Affiliation(s)
- Cayla M Duffy
- Veterans Administration Medical Center, Minneapolis, MN, USA; Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN, USA
| | - Ce Yuan
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN, USA
| | - Lauren E Wisdorf
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN, USA
| | - Charles J Billington
- Veterans Administration Medical Center, Minneapolis, MN, USA; Department of Medicine, University of Minnesota, Minneapolis, MN, USA; Minnesota Obesity Center, St Paul, MN USA
| | - Catherine M Kotz
- Veterans Administration Medical Center, Minneapolis, MN, USA; Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN, USA; Minnesota Obesity Center, St Paul, MN USA
| | - Joshua P Nixon
- Veterans Administration Medical Center, Minneapolis, MN, USA; Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN, USA
| | - Tammy A Butterick
- Veterans Administration Medical Center, Minneapolis, MN, USA; Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN, USA.
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704
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Active immunization against complement factor C5a: a new therapeutic approach for Alzheimer's disease. J Neuroinflammation 2015; 12:150. [PMID: 26275910 PMCID: PMC4537556 DOI: 10.1186/s12974-015-0369-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 07/27/2015] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is the most common neurodegenerative disease characterized by neuronal loss due to amyloid beta aggregations, neurofibrillary tangles, and prominent neuroinflammation. Recently, interference with neuroinflammation as a new therapeutic approach for AD treatment gained great interest. Microglia cells, one of the major contributors in neuroinflammation, are activated in response to misfolded proteins such as amyloid β and cell debris leading to a sustained release of pro-inflammatory mediators. Especially, complement factor C5a and its receptor have been found to be up-regulated in microglia in the immediate surroundings of cerebral amyloid plaques and blocking of C5aR resulted in a reduction of pathological markers in a model of AD. Here, we investigate the effect of active vaccination against the complement factor C5a to interfere with neuroinflammation and neuropathologic alterations in a mouse model of AD. METHODS Short antigenic peptides AFF1 and AFF2, which mimic a C-terminal epitope of C5a, were selected and formulated to vaccines. These vaccines are able to induce a highly specific antibody response to the target protein C5a. Tg2576 mice, a common model of AD, were immunized with these two C5a-peptide vaccines and the induced immune response toward C5a was analyzed by ELISA and Western blot analysis. The influence on memory retention was assessed by a contextual fear conditioning test. Microglia activation and amyloid plaque deposition in the brain was visualized by immunohistochemistry. RESULTS Both C5a-targeting vaccines were highly immunogenic and induced sustained antibody titers against C5a. Tg2576 mice vaccinated at early stages of the disease showed significantly improved contextual memory accompanied by the reduction of microglia activation in the hippocampus and cerebral amyloid plaque load compared to control mice. Late-stage immunization also showed a decrease in the number of activated microglia, and improved memory function, however, had no influence on the amyloid β load. CONCLUSION C5a-peptide vaccines represent a safe and well-tolerated immunotherapy, which is able to induce a strong and specific immune response against the pro-inflammatory molecule C5a. In a mouse model of AD, C5a-peptide vaccines reduce microglia activation and thus neuroinflammation, which is supposed to lead to reduced neuronal dysfunction and AD symptomatic decline.
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705
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Hainsworth AH, Oommen AT, Bridges LR. Endothelial cells and human cerebral small vessel disease. Brain Pathol 2015; 25:44-50. [PMID: 25521176 DOI: 10.1111/bpa.12224] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 10/08/2014] [Indexed: 12/11/2022] Open
Abstract
Brain endothelial cells have unique properties in terms of barrier function, local molecular signaling, regulation of local cerebral blood flow (CBF) and interactions with other members of the neurovascular unit. In cerebral small vessel disease (arteriolosclerosis; SVD), the endothelial cells in small arteries survive, even when mural pathology is advanced and myocytes are severely depleted. Here, we review aspects of altered endothelial functions that have been implicated in SVD: local CBF dysregulation, endothelial activation and blood-brain barrier (BBB) dysfunction. Reduced CBF is reported in the diffuse white matter lesions that are a neuroradiological signature of SVD. This may reflect an underlying deficit in local CBF regulation (possibly via the nitric oxide/cGMP signaling pathway). While many laboratories have observed an association of symptomatic SVD with serum markers of endothelial activation, it is apparent that the origin of these circulating markers need not be brain endothelium. Our own neuropathology studies did not confirm local endothelial activation in small vessels exhibiting SVD. Local BBB failure has been proposed as a cause of SVD and associated parenchymal lesions. Some groups find that computational analyses of magnetic resonance imaging (MRI) scans, following systemic injection of a gadolinium-based contrast agent, suggest that extravasation into brain parenchyma is heightened in people with SVD. Our recent histochemical studies of donated brain tissue, using immunolabeling for large plasma proteins [fibrinogen, immunoglobulin G (IgG)], do not support an association of SVD with recent plasma protein extravasation. It is possible that a trigger leakage episode, or a size-selective loosening of the BBB, participates in SVD pathology.
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Affiliation(s)
- Atticus H Hainsworth
- Molecular and Cellular Biology Research Centre, St Georges University of London, London, UK; Stroke and Dementia Research Centre, St Georges University of London, London, UK
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706
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Walker MD, Dinelle K, Kornelsen R, Lee NV, Miao Q, Adam M, Takhar C, Mak E, Schulzer M, Farrer MJ, Sossi V. [11C]PBR28 PET imaging is sensitive to neuroinflammation in the aged rat. J Cereb Blood Flow Metab 2015; 35:1331-8. [PMID: 25833342 PMCID: PMC4528008 DOI: 10.1038/jcbfm.2015.54] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 01/28/2015] [Accepted: 03/09/2015] [Indexed: 11/09/2022]
Abstract
Neuroinflammation in the aging rat brain was investigated using [(11)C]PBR28 microPET (positron emission tomography) imaging. Normal rats were studied alongside LRRK2 p.G2019S transgenic rats; this mutation increases the risk of Parkinson's disease in humans. Seventy [(11)C]PBR28 PET scans were acquired. Arterial blood sampling enabled tracer kinetic modeling and estimation of VT. In vitro autoradiography was also performed. PBR28 uptake increased with age, without differences between nontransgenic and transgenic rats. In 12 months of aging (4 to 16 months), standard uptake value (SUV) increased by 56% from 0.44 to 0.69 g/mL, whereas VT increased by 91% from 30 to 57 mL/cm(3). Standard uptake value and VT were strongly correlated (r = 0.52, 95% confidence interval (CI) = 0.31 to 0.69, n = 37). The plasma free fraction, fp, was 0.21 ± 0.03 (mean ± standard deviation, n = 53). In vitro binding increased by 19% in 16 months of aging (4 to 20 months). The SUV was less variable across rats than VT; coefficients of variation were 13% (n = 27) and 29% (n = 12). The intraclass correlation coefficient for SUV was 0.53, but was effectively zero for VT. These data show that [(11)C]PBR28 brain uptake increases with age, implying increased microglial activation in the aged brain.
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Affiliation(s)
- Matthew D Walker
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - Katherine Dinelle
- Pacific Parkinson's Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Rick Kornelsen
- Pacific Parkinson's Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Nathan V Lee
- Pacific Parkinson's Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Qing Miao
- TRIUMF, Vancouver, British Columbia, Canada
| | - Mike Adam
- TRIUMF, Vancouver, British Columbia, Canada
| | | | - Edwin Mak
- Pacific Parkinson's Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Michael Schulzer
- Pacific Parkinson's Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Matthew J Farrer
- Department of Medical Genetics, Centre for Applied Neurogenetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Vesna Sossi
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
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707
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Network Comparison of Inflammation in Colorectal Cancer and Alzheimer's Disease. BIOMED RESEARCH INTERNATIONAL 2015; 2015:205247. [PMID: 26273596 PMCID: PMC4529906 DOI: 10.1155/2015/205247] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/16/2015] [Accepted: 02/16/2015] [Indexed: 11/21/2022]
Abstract
Recently, a large clinical study revealed an inverse correlation of individual risk of cancer versus Alzheimer's disease (AD). However, no explanation exists for this anticorrelation at the molecular level; however, inflammation is crucial to the pathogenesis of both diseases, necessitating a need to understand differing signaling usage during inflammatory responses distinct to both diseases. Using a subpathway analysis approach, we identified numerous well-known and previously unknown pathways enriched in datasets from both diseases. Here, we present the quantitative importance of the inflammatory response in the two disease pathologies and summarize signal transduction pathways common to both diseases that are affected by inflammation.
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708
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Morara S, Colangelo AM, Provini L. Microglia-Induced Maladaptive Plasticity Can Be Modulated by Neuropeptides In Vivo. Neural Plast 2015; 2015:135342. [PMID: 26273481 PMCID: PMC4529944 DOI: 10.1155/2015/135342] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 06/25/2015] [Indexed: 02/06/2023] Open
Abstract
Microglia-induced maladaptive plasticity is being recognized as a major cause of deleterious self-sustaining pathological processes that occur in neurodegenerative and neuroinflammatory diseases. Microglia, the primary homeostatic guardian of the central nervous system, exert critical functions both during development, in neural circuit reshaping, and during adult life, in the brain physiological and pathological surveillance. This delicate critical role can be disrupted by neural, but also peripheral, noxious stimuli that can prime microglia to become overreactive to a second noxious stimulus or worsen underlying pathological processes. Among regulators of microglia, neuropeptides can play a major role. Their receptors are widely expressed in microglial cells and neuropeptide challenge can potently influence microglial activity in vitro. More relevantly, this regulator activity has been assessed also in vivo, in experimental models of brain diseases. Neuropeptide action in the central nervous system has been associated with beneficial effects in neurodegenerative and neuroinflammatory pathological experimental models. This review describes some of the mechanisms of the microglia maladaptive plasticity in vivo and how neuropeptide activity can represent a useful therapeutical target in a variety of human brain pathologies.
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Affiliation(s)
- Stefano Morara
- Neuroscience Institute (CNR), Via Vanvitelli 32, 20129 Milano, Italy
- Department of BIOMETRA, University of Milano, Via Vanvitelli 32, 20129 Milano, Italy
| | - Anna Maria Colangelo
- Laboratory of Neuroscience “R. Levi-Montalcini”, Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy
- SYSBIO Centre of Systems Biology, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy
- NeuroMI Milan Center for Neuroscience, University of Milano-Bicocca, 20126 Milano, Italy
| | - Luciano Provini
- Department of BIOMETRA, University of Milano, Via Vanvitelli 32, 20129 Milano, Italy
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709
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Targeting p38 Mitogen-activated Protein Kinase to Reduce the Impact of Neonatal Microglial Priming on Incision-induced Hyperalgesia in the Adult Rat. Anesthesiology 2015; 122:1377-90. [PMID: 25859904 DOI: 10.1097/aln.0000000000000659] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND Neonatal surgical injury triggers developmentally regulated long-term changes that include enhanced hyperalgesia and spinal microglial reactivity after reinjury. To further evaluate priming of response by neonatal hindpaw incision, the authors investigated the functional role of spinal microglial p38 mitogen-activated protein kinase after reincision in adult rodents. METHODS Plantar hindpaw incision was performed in anesthetized adult rats, with or without previous incision on postnatal day 3. Numbers and distribution of phosphorylated-p38 (1, 3, 24 h) and phosphorylated extracellular signal-regulated kinase (15 min, 24 h) immunoreactive cells in the lumbar dorsal horn were compared after adult or neonatal plus adult incision. Withdrawal thresholds evaluated reversal of incision-induced hyperalgesia by p38 inhibition with intrathecal SB203850. RESULTS Neonatal injury significantly increased phosphorylated-p38 expression 3 h after adult incision (55 ± 4 vs. 35 ± 4 cells per section, mean ± SEM, n = 6 to 7, P < 0.01). Increased expression was restricted to microglia, maintained across lumbar segments, and also apparent at 1 and 24 h. Preincision intrathecal SB203850 prevented the enhanced mechanical hyperalgesia in adults with previous neonatal injury and was effective at a lower dose (0.2 vs. 1 mg/kg, n = 8, P < 0.05) and for a longer duration (10 vs. 3 days). Lumbar neuronal phosphorylated extracellular signal-regulated kinase expression reflected the distribution of hindpaw primary afferents, but was not significantly altered by previous incision. CONCLUSIONS Neonatal incision primes spinal neuroglial signaling, and reincision in adult rats unmasks centrally mediated increases in functional microglial reactivity and persistent hyperalgesia. After early life injury, p38 inhibitors may have specific benefit as part of multimodal analgesic regimes to reduce the risk of persistent postsurgical pain.
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710
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Abstract
The past two decades of research into the pathogenesis of Alzheimer disease (AD) have been driven largely by the amyloid hypothesis; the neuroinflammation that is associated with AD has been assumed to be merely a response to pathophysiological events. However, new data from preclinical and clinical studies have established that immune system-mediated actions in fact contribute to and drive AD pathogenesis. These insights have suggested both novel and well-defined potential therapeutic targets for AD, including microglia and several cytokines. In addition, as inflammation in AD primarily concerns the innate immune system - unlike in 'typical' neuroinflammatory diseases such as multiple sclerosis and encephalitides - the concept of neuroinflammation in AD may need refinement.
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711
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Closed head injury in an age-related Alzheimer mouse model leads to an altered neuroinflammatory response and persistent cognitive impairment. J Neurosci 2015; 35:6554-69. [PMID: 25904805 DOI: 10.1523/jneurosci.0291-15.2015] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Epidemiological studies have associated increased risk of Alzheimer's disease (AD)-related clinical symptoms with a medical history of head injury. Currently, little is known about pathophysiology mechanisms linked to this association. Persistent neuroinflammation is one outcome observed in patients after a single head injury. Neuroinflammation is also present early in relevant brain regions during AD pathology progression. In addition, previous mechanistic studies in animal models link neuroinflammation as a contributor to neuropathology and cognitive impairment in traumatic brain injury (TBI) or AD-related models. Therefore, we explored the potential interplay of neuroinflammatory responses in TBI and AD by analysis of the temporal neuroinflammatory changes after TBI in an AD model, the APP/PS1 knock-in (KI) mouse. Discrete temporal aspects of astrocyte, cytokine, and chemokine responses in the injured KI mice were delayed compared with the injured wild-type mice, with a peak neuroinflammatory response in the injured KI mice occurring at 7 d after injury. The neuroinflammatory responses were more persistent in the injured KI mice, leading to a chronic neuroinflammation. At late time points after injury, KI mice exhibited a significant impairment in radial arm water maze performance compared with sham KI mice or injured wild-type mice. Intervention with a small-molecule experimental therapeutic (MW151) that selectively attenuates proinflammatory cytokine production yielded improved cognitive behavior outcomes, consistent with a link between neuroinflammatory responses and altered risk for AD-associated pathology changes with head injury.
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712
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Jones RS, Minogue AM, Fitzpatrick O, Lynch MA. Inhibition of JAK2 attenuates the increase in inflammatory markers in microglia from APP/PS1 mice. Neurobiol Aging 2015; 36:2716-24. [PMID: 26227742 DOI: 10.1016/j.neurobiolaging.2015.04.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 04/27/2015] [Accepted: 04/29/2015] [Indexed: 11/30/2022]
Abstract
There is a wealth of evidence indicating that macrophages adopt distinct phenotypes when exposed to specific stimuli and, in the past few years, accumulating data suggest that microglia behave somewhat similarly. Therefore, microglia can adopt the so-called M1 or M2 phenotypes in response to interferon-γ (IFNγ) and interleukin-4, respectively. Although it has yet to be unequivocally proven in the context of microglia, acutely activated M1 cells are probably protective, although a persistent M1 state is likely to be damaging, whereas M2 cells may be reparative and restorative. In this case, particularly because the current evidence suggests the development of a predominantly M1 state with age and in neurodegenerative diseases, it is important to identify mechanisms by which polarization of microglia can be modulated. The present findings indicate that exposure of cultured microglia to IFNγ increased expressions of the archetypal markers of the M1 phenotype, tumour necrosis factor-α, and inducible nitric oxide synthase, and preexposure of cells to amyloid-β (Aβ) sensitized microglia to subsequent stimulation with IFNγ. Importantly, this synergy was also evident in microglia prepared from the brains of transgenic mice that overexpress amyloid precursor protein (APP) and presenilin 1 (PS1, APP/PS1 mice) and are exposed to a combination of increasing concentrations of endogenous Aβ from 4 or 5 months of age and an age-related increase in IFNγ. Significantly, the JAK2 inhibitor, TG101209, attenuated the IFNγ-induced changes in cultured microglia and in isolated microglia prepared from APP/PS1 mice. These findings suggest that targeting JAK2 may be a potential strategy for reducing neuroinflammation in Alzheimer's disease.
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Affiliation(s)
- Raasay S Jones
- Trinity College Institute of Neuroscience, Trinity College, Dublin, Ireland
| | - Aedín M Minogue
- Trinity College Institute of Neuroscience, Trinity College, Dublin, Ireland
| | - Orla Fitzpatrick
- Trinity College Institute of Neuroscience, Trinity College, Dublin, Ireland
| | - Marina A Lynch
- Trinity College Institute of Neuroscience, Trinity College, Dublin, Ireland.
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713
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Sun X, Voloboueva LA, Stary CM, Giffard RG. Physiologically normal 5% O2 supports neuronal differentiation and resistance to inflammatory injury in neural stem cell cultures. J Neurosci Res 2015; 93:1703-12. [PMID: 26147710 DOI: 10.1002/jnr.23615] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 06/09/2015] [Accepted: 06/15/2015] [Indexed: 01/09/2023]
Abstract
Recent studies have demonstrated that neural stem cell (NSC) culture at physiologically normoxic conditions (2-5% O2) is advantageous in terms of neuronal differentiation and survival. Neuronal differentiation is accompanied by a remarkable shift to mitochondrial oxidative metabolism compared with preferentially glycolytic metabolism of proliferating cells. However, metabolic changes induced by growth in a normoxic (5%) O2 culture environment in NSCs have been minimally explored. This study demonstrates that culturing under 5% O2 conditions results in higher levels of mitochondrial oxidative metabolism, decreased glycolysis, and reduced levels of reactive oxygen species in NSC cultures. Inflammation is one of the major environmental factors limiting postinjury NSC neuronal differentiation and survival. Our results show that NSCs differentiated under 5% O2 conditions possess better resistance to in vitro inflammatory injury compared with those exposed to 20% O2. The present work demonstrates that lower, more physiologically normal O2 levels support metabolic changes induced during NSC neuronal differentiation and provide increased resistance to inflammatory injury, thus highlighting O2 tension as an important determinant of cell fate and survival in various stem cell therapies.
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Affiliation(s)
- Xiaoyun Sun
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, California
| | - Ludmila A Voloboueva
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, California
| | - Creed M Stary
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, California
| | - Rona G Giffard
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, California
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714
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Skaper SD, Facci L, Barbierato M, Zusso M, Bruschetta G, Impellizzeri D, Cuzzocrea S, Giusti P. N-Palmitoylethanolamine and Neuroinflammation: a Novel Therapeutic Strategy of Resolution. Mol Neurobiol 2015; 52:1034-42. [PMID: 26055231 DOI: 10.1007/s12035-015-9253-8] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Indexed: 02/06/2023]
Abstract
Inflammation is fundamentally a protective cellular response aimed at removing injurious stimuli and initiating the healing process. However, when prolonged, it can override the bounds of physiological control and becomes destructive. Inflammation is a key element in the pathobiology of chronic pain, neurodegenerative diseases, stroke, spinal cord injury, and neuropsychiatric disorders. Glia, key players in such nervous system disorders, are not only capable of expressing a pro-inflammatory phenotype but respond also to inflammatory signals released from cells of immune origin such as mast cells. Chronic inflammatory processes may be counteracted by a program of resolution that includes the production of lipid mediators endowed with the capacity to switch off inflammation. These naturally occurring lipid signaling molecules include the N-acylethanolamines, N-arachidonoylethanolamine (an endocannabinoid), and its congener N-palmitoylethanolamine (palmitoylethanolamide or PEA). PEA may play a role in maintaining cellular homeostasis when faced with external stressors provoking, for example, inflammation. PEA is efficacious in mast cell-mediated models of neurogenic inflammation and neuropathic pain and is neuroprotective in models of stroke, spinal cord injury, traumatic brain injury, and Parkinson disease. PEA in micronized/ultramicronized form shows superior oral efficacy in inflammatory pain models when compared to naïve PEA. Intriguingly, while PEA has no antioxidant effects per se, its co-ultramicronization with the flavonoid luteolin is more efficacious than either molecule alone. Inhibiting or modulating the enzymatic breakdown of PEA represents a complementary therapeutic approach to treat neuroinflammation. This review is intended to discuss the role of mast cells and glia in neuroinflammation and strategies to modulate their activation based on leveraging natural mechanisms with the capacity for self-defense against inflammation.
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Affiliation(s)
- Stephen D Skaper
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Largo "Egidio Meneghetti" 2, 35131, Padua, Italy,
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715
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Wes PD, Holtman IR, Boddeke EW, Möller T, Eggen BJ. Next generation transcriptomics and genomics elucidate biological complexity of microglia in health and disease. Glia 2015; 64:197-213. [DOI: 10.1002/glia.22866] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 05/11/2015] [Indexed: 12/11/2022]
Affiliation(s)
| | - Inge R. Holtman
- Department of NeuroscienceSection Medical Physiology, University of Groningen, University Medical Center GroningenGroningen The Netherlands
| | - Erik W.G.M. Boddeke
- Department of NeuroscienceSection Medical Physiology, University of Groningen, University Medical Center GroningenGroningen The Netherlands
| | | | - Bart J.L. Eggen
- Department of NeuroscienceSection Medical Physiology, University of Groningen, University Medical Center GroningenGroningen The Netherlands
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716
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Deleidi M, Jäggle M, Rubino G. Immune aging, dysmetabolism, and inflammation in neurological diseases. Front Neurosci 2015; 9:172. [PMID: 26089771 PMCID: PMC4453474 DOI: 10.3389/fnins.2015.00172] [Citation(s) in RCA: 180] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Accepted: 04/28/2015] [Indexed: 12/17/2022] Open
Abstract
As we age, the immune system undergoes a process of senescence accompanied by the increased production of proinflammatory cytokines, a chronic subclinical condition named as “inflammaging”. Emerging evidence from human and experimental models suggest that immune senescence also affects the central nervous system and promotes neuronal dysfunction, especially within susceptible neuronal populations. In this review we discuss the potential role of immune aging, inflammation and metabolic derangement in neurological diseases. The discovery of novel therapeutic strategies targeting age-linked inflammation may promote healthy brain aging and the treatment of neurodegenerative as well as neuropsychiatric disorders.
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Affiliation(s)
- Michela Deleidi
- Department of Neurodegenerative Diseases, German Center for Neurodegenerative Diseases (DZNE), Hertie Institute for Clinical Brain Research, University of Tübingen Tübingen, Germany
| | - Madeline Jäggle
- Department of Neurodegenerative Diseases, German Center for Neurodegenerative Diseases (DZNE), Hertie Institute for Clinical Brain Research, University of Tübingen Tübingen, Germany
| | - Graziella Rubino
- Department of Internal Medicine II, Center for Medical Research, University of Tübingen Tübingen, Germany
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717
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Inflammation, Iron, Energy Failure, and Oxidative Stress in the Pathogenesis of Multiple Sclerosis. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2015:725370. [PMID: 26106458 PMCID: PMC4461760 DOI: 10.1155/2015/725370] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Revised: 05/06/2015] [Accepted: 05/18/2015] [Indexed: 01/28/2023]
Abstract
Multiple sclerosis is a chronic inflammatory demyelinating disease of the central nervous system. Different trigger pathologies have been suggested by the primary cytodegenerative “inside-out” and primary inflammation-driven “outside-in” hypotheses. Recent data indicate that mitochondrial injury and subsequent energy failure are key factors in the induction of demyelination and neurodegeneration. The brain weighs only a few percent of the body mass but accounts for approximately 20% of the total basal oxygen consumption of mitochondria. Oxidative stress induces mitochondrial injury in patients with multiple sclerosis and energy failure in the central nervous system of susceptible individuals. The interconnected mechanisms responsible for free radical production in patients with multiple sclerosis are as follows: (i) inflammation-induced production of free radicals by activated immune cells, (ii) liberation of iron from the myelin sheets during demyelination, and (iii) mitochondrial injury and thus energy failure-related free radical production. In the present review, the different sources of oxidative stress and their relationships to patients with multiple sclerosis considering tissue injury mechanisms and clinical aspects have been discussed.
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718
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Cobb CA, Cole MP. Oxidative and nitrative stress in neurodegeneration. Neurobiol Dis 2015; 84:4-21. [PMID: 26024962 DOI: 10.1016/j.nbd.2015.04.020] [Citation(s) in RCA: 175] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 04/20/2015] [Accepted: 04/21/2015] [Indexed: 12/19/2022] Open
Abstract
Aerobes require oxygen for metabolism and normal free radical formation. As a result, maintaining the redox homeostasis is essential for brain cell survival due to their high metabolic energy requirement to sustain electrochemical gradients, neurotransmitter release, and membrane lipid stability. Further, brain antioxidant levels are limited compared to other organs and less able to compensate for reactive oxygen and nitrogen species (ROS/RNS) generation which contribute oxidative/nitrative stress (OS/NS). Antioxidant treatments such as vitamin E, minocycline, and resveratrol mediate neuroprotection by prolonging the incidence of or reversing OS and NS conditions. Redox imbalance occurs when the antioxidant capacity is overwhelmed, consequently leading to activation of alternate pathways that remain quiescent under normal conditions. If OS/NS fails to lead to adaptation, tissue damage and injury ensue, resulting in cell death and/or disease. The progression of OS/NS-mediated neurodegeneration along with contributions from microglial activation, dopamine metabolism, and diabetes comprise a detailed interconnected pathway. This review proposes a significant role for OS/NS and more specifically, lipid peroxidation (LPO) and other lipid modifications, by triggering microglial activation to elicit a neuroinflammatory state potentiated by diabetes or abnormal dopamine metabolism. Subsequently, sustained stress in the neuroinflammatory state overwhelms cellular defenses and prompts neurotoxicity resulting in the onset or amplification of brain damage.
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Affiliation(s)
- Catherine A Cobb
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Louisville, Louisville, KY 40202, USA
| | - Marsha P Cole
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Louisville, Louisville, KY 40202, USA; Department of Physiology and Biophysics, School of Medicine, University of Louisville, Louisville, KY 40202, USA.
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719
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Holtman IR, Raj DD, Miller JA, Schaafsma W, Yin Z, Brouwer N, Wes PD, Möller T, Orre M, Kamphuis W, Hol EM, Boddeke EWGM, Eggen BJL. Induction of a common microglia gene expression signature by aging and neurodegenerative conditions: a co-expression meta-analysis. Acta Neuropathol Commun 2015; 3:31. [PMID: 26001565 PMCID: PMC4489356 DOI: 10.1186/s40478-015-0203-5] [Citation(s) in RCA: 409] [Impact Index Per Article: 45.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 04/12/2015] [Indexed: 12/16/2022] Open
Abstract
Introduction Microglia are tissue macrophages of the central nervous system that monitor brain homeostasis and react upon neuronal damage and stress. Aging and neurodegeneration induce a hypersensitive, pro-inflammatory phenotype, referred to as primed microglia. To determine the gene expression signature of priming, the transcriptomes of microglia in aging, Alzheimer’s disease (AD), and amyotrophic lateral sclerosis (ALS) mouse models were compared using Weighted Gene Co-expression Network Analysis (WGCNA). Results A highly consistent consensus transcriptional profile of up-regulated genes was identified, which prominently differed from the acute inflammatory gene network induced by lipopolysaccharide (LPS). Where the acute inflammatory network was significantly enriched for NF-κB signaling, the primed microglia profile contained key features related to phagosome, lysosome, antigen presentation, and AD signaling. In addition, specific signatures for aging, AD, and ALS were identified. Conclusion Microglia priming induces a highly conserved transcriptional signature with aging- and disease-specific aspects. Electronic supplementary material The online version of this article (doi:10.1186/s40478-015-0203-5) contains supplementary material, which is available to authorized users.
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720
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Layé S, Madore C, St-Amour I, Delpech JC, Joffre C, Nadjar A, Calon F. N-3 polyunsaturated fatty acid and neuroinflammation in aging and Alzheimer’s disease. ACTA ACUST UNITED AC 2015. [DOI: 10.3233/nua-150049] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Sophie Layé
- Nutrition et Neurobiologie Intégrée, Bordeaux Cedex, France
- University of Bordeaux, Bordeaux, France
- OptiNutriBrain International associated Laboratory (NutriNeuro France-INAF Canada)
| | - Charlotte Madore
- Nutrition et Neurobiologie Intégrée, Bordeaux Cedex, France
- University of Bordeaux, Bordeaux, France
| | - Isabelle St-Amour
- Faculté de Pharmacie, Université Laval; Centre de Recherche du CHU de Québec, Québec, Canada
| | - Jean-Christophe Delpech
- Nutrition et Neurobiologie Intégrée, Bordeaux Cedex, France
- University of Bordeaux, Bordeaux, France
| | - Corinne Joffre
- Nutrition et Neurobiologie Intégrée, Bordeaux Cedex, France
- University of Bordeaux, Bordeaux, France
- OptiNutriBrain International associated Laboratory (NutriNeuro France-INAF Canada)
| | - Agnès Nadjar
- Nutrition et Neurobiologie Intégrée, Bordeaux Cedex, France
- University of Bordeaux, Bordeaux, France
- OptiNutriBrain International associated Laboratory (NutriNeuro France-INAF Canada)
| | - Frédéric Calon
- Faculté de Pharmacie, Université Laval; Centre de Recherche du CHU de Québec, Québec, Canada
- OptiNutriBrain International associated Laboratory (NutriNeuro France-INAF Canada)
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721
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Rosset MB, Lui G, Dansokho C, Chaigneau T, Dorothée G. Vaccine-induced Aβ-specific CD8+ T cells do not trigger autoimmune neuroinflammation in a murine model of Alzheimer's disease. J Neuroinflammation 2015; 12:95. [PMID: 25982697 PMCID: PMC4448209 DOI: 10.1186/s12974-015-0317-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 05/03/2015] [Indexed: 11/10/2022] Open
Abstract
Background Active immunization against Aβ was reported to have a therapeutic effect in murine models of Alzheimer’s disease. Clinical Aβ vaccination trial AN1792 was interrupted due to the development in 6 % of the patients of meningoencephalitis likely involving pro-inflammatory CD4+ T cells. However, the potential implication of auto-aggressive anti-Aβ CD8+ T cells has been poorly investigated. Methods Potential MHC-I-restricted Aβ-derived epitopes were first analyzed for their capacity to recruit functional CD8+ T cell responses in mouse models. Their impact on migration of CD8+ T cells into the brain parenchyma and potential induction of meningoencephalitis and/or neuronal damage was investigated upon vaccination in the APPPS1 mouse model of AD. Results We identified one nonamer peptide, Aβ33-41, which was naturally processed and presented in association with H-2-Db molecule on neurons and CD11b+ microglia. Upon optimization of anchor residues for enhanced binding to H-2-Db, immunization with the modified Aβ33-41NP peptide elicited Aβ-specific IFNγ-secreting CD8+ T cells, which are cytotoxic towards Aβ-expressing targets. Whereas T cell infiltration in the brain of APPPS1 mice is dominated by CD3+CD8− T cells and increases with disease evolution between 4 and 7 months of age, a predominance of CD3+CD8+ over CD3+CD8− cells was observed in 6- to 7-month-old APPPS1 but not in WT animals, only after vaccination with Aβ33-41NP. The number of CD11b+ mononuclear phagocytes, which significantly increases with age in the brain of APPPS1 mice, was reduced following immunization with Aβ33-41NP. Despite peripheral activation of Aβ-specific CD8+ cytotoxic effectors and enhanced infiltration of CD8+ T cells in the brain of Aβ33-41NP-immunized APPPS1 mice, no clinical signs of severe autoimmune neuroinflammation were observed. Conclusions Altogether, these results suggest that Aβ-specific CD8+ T cells are not major contributors to meningoencephalitis in response to Aβ vaccination.
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Affiliation(s)
- Martine Bruley Rosset
- INSERM, UMR_S 938, CdR Saint-Antoine, Laboratory Immune System, Neuroinflammation and Neurodegenerative Diseases, Inflammation-Immunopathology-Biotherapy Department (DHU i2B), Hôpital Saint-Antoine, 184 rue du Faubourg Saint-Antoine, F-75012, Paris, France. .,Sorbonne Universités, UPMC Univ Paris 06, UMR_S 938, CdR Saint-Antoine, Hôpital Saint-Antoine, 184 rue du Faubourg Saint-Antoine, F-75012, Paris, France.
| | - Gabrielle Lui
- INSERM, UMR_S 938, CdR Saint-Antoine, Laboratory Immune System, Neuroinflammation and Neurodegenerative Diseases, Inflammation-Immunopathology-Biotherapy Department (DHU i2B), Hôpital Saint-Antoine, 184 rue du Faubourg Saint-Antoine, F-75012, Paris, France. .,Sorbonne Universités, UPMC Univ Paris 06, UMR_S 938, CdR Saint-Antoine, Hôpital Saint-Antoine, 184 rue du Faubourg Saint-Antoine, F-75012, Paris, France.
| | - Cira Dansokho
- INSERM, UMR_S 938, CdR Saint-Antoine, Laboratory Immune System, Neuroinflammation and Neurodegenerative Diseases, Inflammation-Immunopathology-Biotherapy Department (DHU i2B), Hôpital Saint-Antoine, 184 rue du Faubourg Saint-Antoine, F-75012, Paris, France. .,Sorbonne Universités, UPMC Univ Paris 06, UMR_S 938, CdR Saint-Antoine, Hôpital Saint-Antoine, 184 rue du Faubourg Saint-Antoine, F-75012, Paris, France.
| | - Thomas Chaigneau
- INSERM, UMR_S 938, CdR Saint-Antoine, Laboratory Immune System, Neuroinflammation and Neurodegenerative Diseases, Inflammation-Immunopathology-Biotherapy Department (DHU i2B), Hôpital Saint-Antoine, 184 rue du Faubourg Saint-Antoine, F-75012, Paris, France. .,Sorbonne Universités, UPMC Univ Paris 06, UMR_S 938, CdR Saint-Antoine, Hôpital Saint-Antoine, 184 rue du Faubourg Saint-Antoine, F-75012, Paris, France.
| | - Guillaume Dorothée
- INSERM, UMR_S 938, CdR Saint-Antoine, Laboratory Immune System, Neuroinflammation and Neurodegenerative Diseases, Inflammation-Immunopathology-Biotherapy Department (DHU i2B), Hôpital Saint-Antoine, 184 rue du Faubourg Saint-Antoine, F-75012, Paris, France. .,Sorbonne Universités, UPMC Univ Paris 06, UMR_S 938, CdR Saint-Antoine, Hôpital Saint-Antoine, 184 rue du Faubourg Saint-Antoine, F-75012, Paris, France.
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Folch J, Petrov D, Ettcheto M, Pedrós I, Abad S, Beas-Zarate C, Lazarowski A, Marin M, Olloquequi J, Auladell C, Camins A. Masitinib for the treatment of mild to moderate Alzheimer's disease. Expert Rev Neurother 2015; 15:587-96. [PMID: 25961655 DOI: 10.1586/14737175.2015.1045419] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Alzheimer's disease (AD) is a degenerative neurological disorder that is the most common cause of dementia and disability in older patients. Available treatments are symptomatic in nature and are only sufficient to improve the quality of life of AD patients temporarily. A potential strategy, currently under investigation, is to target cell-signaling pathways associated with neurodegeneration, in order to decrease neuroinflammation, excitotoxicity, and to improve cognitive functions. Current review centers on the role of neuroinflammation and the specific contribution of mast cells to AD pathophysiology. The authors look at masitinib therapy and the evidence presented through preclinical and clinical trials. Dual actions of masitinib as an inhibitor of mast cell-glia axis and a Fyn kinase blocker are discussed in the context of AD pathology. Masitinib is in Phase III clinical trials for the treatment of malignant melanoma, mastocytosis, multiple myeloma, gastrointestinal cancer and pancreatic cancer. It is also in Phase II/III clinical trials for the treatment of multiple sclerosis, rheumatoid arthritis and AD. Additional research is warranted to better investigate the potential effects of masitinib in combination with other drugs employed in AD treatment.
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Affiliation(s)
- Jaume Folch
- Unitat de Bioquimica i Biotecnología, Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Reus, Tarragona, Spain
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Butchart J, Brook L, Hopkins V, Teeling J, Püntener U, Culliford D, Sharples R, Sharif S, McFarlane B, Raybould R, Thomas R, Passmore P, Perry VH, Holmes C. Etanercept in Alzheimer disease: A randomized, placebo-controlled, double-blind, phase 2 trial. Neurology 2015; 84:2161-8. [PMID: 25934853 DOI: 10.1212/wnl.0000000000001617] [Citation(s) in RCA: 173] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 02/15/2015] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVES To determine whether the tumor necrosis factor α inhibitor etanercept is well tolerated and obtain preliminary data on its safety in Alzheimer disease dementia. METHODS In a double-blind study, patients with mild to moderate Alzheimer disease dementia were randomized (1:1) to subcutaneous etanercept (50 mg) once weekly or identical placebo over a 24-week period. Tolerability and safety of this medication was recorded including secondary outcomes of cognition, global function, behavior, and systemic cytokine levels at baseline, 12 weeks, 24 weeks, and following a 4-week washout period. This trial is registered with EudraCT (2009-013400-31) and ClinicalTrials.gov (NCT01068353). RESULTS Forty-one participants (mean age 72.4 years; 61% men) were randomized to etanercept (n = 20) or placebo (n = 21). Etanercept was well tolerated; 90% of participants (18/20) completed the study compared with 71% (15/21) in the placebo group. Although infections were more common in the etanercept group, there were no serious adverse events or new safety concerns. While there were some interesting trends that favored etanercept, there were no statistically significant changes in cognition, behavior, or global function. CONCLUSIONS This study showed that subcutaneous etanercept (50 mg/wk) was well tolerated in this small group of patients with Alzheimer disease dementia, but a larger more heterogeneous group needs to be tested before recommending its use for broader groups of patients. CLASSIFICATION OF EVIDENCE This study shows Class I evidence that weekly subcutaneous etanercept is well tolerated in Alzheimer disease dementia.
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Affiliation(s)
- Joseph Butchart
- From the Faculty of Medicine, Clinical Experimental Sciences (J.B., L.B., D.C., C.H.), and Faculty of Natural and Environmental Science, Centre for Biological Sciences (J.T., U.P., V.H.P.), University of Southampton; Memory Assessment and Research Centre (J.B., L.B., V.H., R.S., S.S., C.H.), Moorgreen Hospital, Southern Health Foundation Trust, Southampton; Becton Health Centre (B.M.), Southern Health Foundation Trust, New Milton; Centre for Public Health (P.P.), Queens University Belfast; MRC Centre for Neuropsychiatric Genetics and Genomics (R.R., R.T.), Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, UK
| | - Laura Brook
- From the Faculty of Medicine, Clinical Experimental Sciences (J.B., L.B., D.C., C.H.), and Faculty of Natural and Environmental Science, Centre for Biological Sciences (J.T., U.P., V.H.P.), University of Southampton; Memory Assessment and Research Centre (J.B., L.B., V.H., R.S., S.S., C.H.), Moorgreen Hospital, Southern Health Foundation Trust, Southampton; Becton Health Centre (B.M.), Southern Health Foundation Trust, New Milton; Centre for Public Health (P.P.), Queens University Belfast; MRC Centre for Neuropsychiatric Genetics and Genomics (R.R., R.T.), Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, UK
| | - Vivienne Hopkins
- From the Faculty of Medicine, Clinical Experimental Sciences (J.B., L.B., D.C., C.H.), and Faculty of Natural and Environmental Science, Centre for Biological Sciences (J.T., U.P., V.H.P.), University of Southampton; Memory Assessment and Research Centre (J.B., L.B., V.H., R.S., S.S., C.H.), Moorgreen Hospital, Southern Health Foundation Trust, Southampton; Becton Health Centre (B.M.), Southern Health Foundation Trust, New Milton; Centre for Public Health (P.P.), Queens University Belfast; MRC Centre for Neuropsychiatric Genetics and Genomics (R.R., R.T.), Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, UK
| | - Jessica Teeling
- From the Faculty of Medicine, Clinical Experimental Sciences (J.B., L.B., D.C., C.H.), and Faculty of Natural and Environmental Science, Centre for Biological Sciences (J.T., U.P., V.H.P.), University of Southampton; Memory Assessment and Research Centre (J.B., L.B., V.H., R.S., S.S., C.H.), Moorgreen Hospital, Southern Health Foundation Trust, Southampton; Becton Health Centre (B.M.), Southern Health Foundation Trust, New Milton; Centre for Public Health (P.P.), Queens University Belfast; MRC Centre for Neuropsychiatric Genetics and Genomics (R.R., R.T.), Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, UK
| | - Ursula Püntener
- From the Faculty of Medicine, Clinical Experimental Sciences (J.B., L.B., D.C., C.H.), and Faculty of Natural and Environmental Science, Centre for Biological Sciences (J.T., U.P., V.H.P.), University of Southampton; Memory Assessment and Research Centre (J.B., L.B., V.H., R.S., S.S., C.H.), Moorgreen Hospital, Southern Health Foundation Trust, Southampton; Becton Health Centre (B.M.), Southern Health Foundation Trust, New Milton; Centre for Public Health (P.P.), Queens University Belfast; MRC Centre for Neuropsychiatric Genetics and Genomics (R.R., R.T.), Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, UK
| | - David Culliford
- From the Faculty of Medicine, Clinical Experimental Sciences (J.B., L.B., D.C., C.H.), and Faculty of Natural and Environmental Science, Centre for Biological Sciences (J.T., U.P., V.H.P.), University of Southampton; Memory Assessment and Research Centre (J.B., L.B., V.H., R.S., S.S., C.H.), Moorgreen Hospital, Southern Health Foundation Trust, Southampton; Becton Health Centre (B.M.), Southern Health Foundation Trust, New Milton; Centre for Public Health (P.P.), Queens University Belfast; MRC Centre for Neuropsychiatric Genetics and Genomics (R.R., R.T.), Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, UK
| | - Richard Sharples
- From the Faculty of Medicine, Clinical Experimental Sciences (J.B., L.B., D.C., C.H.), and Faculty of Natural and Environmental Science, Centre for Biological Sciences (J.T., U.P., V.H.P.), University of Southampton; Memory Assessment and Research Centre (J.B., L.B., V.H., R.S., S.S., C.H.), Moorgreen Hospital, Southern Health Foundation Trust, Southampton; Becton Health Centre (B.M.), Southern Health Foundation Trust, New Milton; Centre for Public Health (P.P.), Queens University Belfast; MRC Centre for Neuropsychiatric Genetics and Genomics (R.R., R.T.), Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, UK
| | - Saif Sharif
- From the Faculty of Medicine, Clinical Experimental Sciences (J.B., L.B., D.C., C.H.), and Faculty of Natural and Environmental Science, Centre for Biological Sciences (J.T., U.P., V.H.P.), University of Southampton; Memory Assessment and Research Centre (J.B., L.B., V.H., R.S., S.S., C.H.), Moorgreen Hospital, Southern Health Foundation Trust, Southampton; Becton Health Centre (B.M.), Southern Health Foundation Trust, New Milton; Centre for Public Health (P.P.), Queens University Belfast; MRC Centre for Neuropsychiatric Genetics and Genomics (R.R., R.T.), Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, UK
| | - Brady McFarlane
- From the Faculty of Medicine, Clinical Experimental Sciences (J.B., L.B., D.C., C.H.), and Faculty of Natural and Environmental Science, Centre for Biological Sciences (J.T., U.P., V.H.P.), University of Southampton; Memory Assessment and Research Centre (J.B., L.B., V.H., R.S., S.S., C.H.), Moorgreen Hospital, Southern Health Foundation Trust, Southampton; Becton Health Centre (B.M.), Southern Health Foundation Trust, New Milton; Centre for Public Health (P.P.), Queens University Belfast; MRC Centre for Neuropsychiatric Genetics and Genomics (R.R., R.T.), Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, UK
| | - Rachel Raybould
- From the Faculty of Medicine, Clinical Experimental Sciences (J.B., L.B., D.C., C.H.), and Faculty of Natural and Environmental Science, Centre for Biological Sciences (J.T., U.P., V.H.P.), University of Southampton; Memory Assessment and Research Centre (J.B., L.B., V.H., R.S., S.S., C.H.), Moorgreen Hospital, Southern Health Foundation Trust, Southampton; Becton Health Centre (B.M.), Southern Health Foundation Trust, New Milton; Centre for Public Health (P.P.), Queens University Belfast; MRC Centre for Neuropsychiatric Genetics and Genomics (R.R., R.T.), Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, UK
| | - Rhodri Thomas
- From the Faculty of Medicine, Clinical Experimental Sciences (J.B., L.B., D.C., C.H.), and Faculty of Natural and Environmental Science, Centre for Biological Sciences (J.T., U.P., V.H.P.), University of Southampton; Memory Assessment and Research Centre (J.B., L.B., V.H., R.S., S.S., C.H.), Moorgreen Hospital, Southern Health Foundation Trust, Southampton; Becton Health Centre (B.M.), Southern Health Foundation Trust, New Milton; Centre for Public Health (P.P.), Queens University Belfast; MRC Centre for Neuropsychiatric Genetics and Genomics (R.R., R.T.), Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, UK
| | - Peter Passmore
- From the Faculty of Medicine, Clinical Experimental Sciences (J.B., L.B., D.C., C.H.), and Faculty of Natural and Environmental Science, Centre for Biological Sciences (J.T., U.P., V.H.P.), University of Southampton; Memory Assessment and Research Centre (J.B., L.B., V.H., R.S., S.S., C.H.), Moorgreen Hospital, Southern Health Foundation Trust, Southampton; Becton Health Centre (B.M.), Southern Health Foundation Trust, New Milton; Centre for Public Health (P.P.), Queens University Belfast; MRC Centre for Neuropsychiatric Genetics and Genomics (R.R., R.T.), Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, UK
| | - V Hugh Perry
- From the Faculty of Medicine, Clinical Experimental Sciences (J.B., L.B., D.C., C.H.), and Faculty of Natural and Environmental Science, Centre for Biological Sciences (J.T., U.P., V.H.P.), University of Southampton; Memory Assessment and Research Centre (J.B., L.B., V.H., R.S., S.S., C.H.), Moorgreen Hospital, Southern Health Foundation Trust, Southampton; Becton Health Centre (B.M.), Southern Health Foundation Trust, New Milton; Centre for Public Health (P.P.), Queens University Belfast; MRC Centre for Neuropsychiatric Genetics and Genomics (R.R., R.T.), Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, UK
| | - Clive Holmes
- From the Faculty of Medicine, Clinical Experimental Sciences (J.B., L.B., D.C., C.H.), and Faculty of Natural and Environmental Science, Centre for Biological Sciences (J.T., U.P., V.H.P.), University of Southampton; Memory Assessment and Research Centre (J.B., L.B., V.H., R.S., S.S., C.H.), Moorgreen Hospital, Southern Health Foundation Trust, Southampton; Becton Health Centre (B.M.), Southern Health Foundation Trust, New Milton; Centre for Public Health (P.P.), Queens University Belfast; MRC Centre for Neuropsychiatric Genetics and Genomics (R.R., R.T.), Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, UK.
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Abstract
Since the genome-wide association studies in Alzheimer's disease have highlighted inflammation as a driver of the disease rather than a consequence of the ongoing neurodegeneration, numerous studies have been performed to identify specific immune profiles associated with healthy, ageing, or diseased brain. However, these studies have been performed mainly in in vitro or animal models, which recapitulate only some aspects of the pathophysiology of human Alzheimer's disease. In this review, we discuss the availability of human post-mortem tissue through brain banks, the limitations associated with its use, the technical tools available, and the neuroimmune aspects to explore in order to validate in the human brain the experimental observations arising from animal models.
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Affiliation(s)
- Diego Gomez-Nicola
- />Centre for Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD UK
| | - Delphine Boche
- />Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD UK
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725
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Gan P, Zhang L, Chen Y, Zhang Y, Zhang F, Zhou X, Zhang X, Gao B, Zhen X, Zhang J, Zheng LT. Anti-inflammatory effects of glaucocalyxin B in microglia cells. J Pharmacol Sci 2015; 128:35-46. [PMID: 26003084 DOI: 10.1016/j.jphs.2015.04.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 04/07/2015] [Accepted: 04/09/2015] [Indexed: 11/29/2022] Open
Abstract
Over-activated microglia is involved in various kinds of neurodegenerative process including Parkinson, Alzheimer and HIV dementia. Suppression of microglial over activation has emerged as a novel strategy for treatment of neuroinflammation-based neurodegeneration. In the current study, anti-inflammatory and neuroprotective effects of the ent-kauranoid diterpenoids, which were isolated from the aerial parts of Rabdosia japonica (Burm. f.) var. glaucocalyx (Maxim.) Hara, were investigated in cultured microglia cells. Glaucocalyxin B (GLB), one of five ent-kauranoid diterpenoids, significantly decreased the generation of nitric oxide (NO), tumor necrosis factor (TNF)-α, interleukin (IL)-1β, cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) in the lipopolysaccharide (LPS)-activated microglia cells. In addition, GLB inhibited activation of nuclear factor-κB (NF-κB), p38 mitogen-activated protein kinase (MAPK) and generation of reactive oxygen species (ROS) in LPS-activated microglia cells. Furthermore, GLB strongly induced the expression of heme oxygenase (HO)-1 in BV-2 microglia cells. Finally, GLB exhibited neuroprotective effect by preventing over-activated microglia induced neurotoxicity in a microglia/neuron co-culture model. Taken together, the present study demonstrated that the GLB possesses anti-nueroinflammatory activity, and might serve as a potential therapeutic agent for treating neuroinflammatory diseases.
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Affiliation(s)
- Ping Gan
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuropsychiatric Disorders & Department of Pharmacology, College of Pharmaceutical Sciences and the Collaborative Innovation Center for Brain Science, Soochow University, Suzhou 215123, PR China
| | - Li Zhang
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuropsychiatric Disorders & Department of Pharmacology, College of Pharmaceutical Sciences and the Collaborative Innovation Center for Brain Science, Soochow University, Suzhou 215123, PR China
| | - Yanke Chen
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuropsychiatric Disorders & Department of Pharmacology, College of Pharmaceutical Sciences and the Collaborative Innovation Center for Brain Science, Soochow University, Suzhou 215123, PR China
| | - Yu Zhang
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuropsychiatric Disorders & Department of Pharmacology, College of Pharmaceutical Sciences and the Collaborative Innovation Center for Brain Science, Soochow University, Suzhou 215123, PR China
| | - Fali Zhang
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuropsychiatric Disorders & Department of Pharmacology, College of Pharmaceutical Sciences and the Collaborative Innovation Center for Brain Science, Soochow University, Suzhou 215123, PR China
| | - Xiang Zhou
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuropsychiatric Disorders & Department of Pharmacology, College of Pharmaceutical Sciences and the Collaborative Innovation Center for Brain Science, Soochow University, Suzhou 215123, PR China
| | - Xiaohu Zhang
- Department of Medical Chemistry, College of Pharmaceutical Sciences, Soochow University, Suzhou 215123, PR China
| | - Bo Gao
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuropsychiatric Disorders & Department of Pharmacology, College of Pharmaceutical Sciences and the Collaborative Innovation Center for Brain Science, Soochow University, Suzhou 215123, PR China
| | - Xuechu Zhen
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuropsychiatric Disorders & Department of Pharmacology, College of Pharmaceutical Sciences and the Collaborative Innovation Center for Brain Science, Soochow University, Suzhou 215123, PR China
| | - Jian Zhang
- Department of Natural Medical Chemistry, College of Pharmaceutical Sciences, Soochow University, Suzhou 215123, PR China.
| | - Long Tai Zheng
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuropsychiatric Disorders & Department of Pharmacology, College of Pharmaceutical Sciences and the Collaborative Innovation Center for Brain Science, Soochow University, Suzhou 215123, PR China.
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726
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Microglia in Glia-Neuron Co-cultures Exhibit Robust Phagocytic Activity Without Concomitant Inflammation or Cytotoxicity. Cell Mol Neurobiol 2015; 35:961-75. [PMID: 25894384 DOI: 10.1007/s10571-015-0191-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 03/28/2015] [Indexed: 12/19/2022]
Abstract
A simple method to co-culture granule neurons and glia from a single brain region is described, and microglia activation profiles are assessed in response to naturally occurring neuronal apoptosis, excitotoxin-induced neuronal death, and lipopolysaccharide (LPS) addition. Using neonatal rat cerebellar cortex as a tissue source, glial proliferation is regulated by omission or addition of the mitotic inhibitor cytosine arabinoside (AraC). After 7-8 days in vitro, microglia in AraC(-) cultures are abundant and activated based on their amoeboid morphology, expressions of ED1 and Iba1, and ability to phagocytose polystyrene beads and the majority of neurons undergoing spontaneous apoptosis. Microglia and phagocytic activities are sparse in AraC(+) cultures. Following exposure to excitotoxic kainate concentrations, microglia in AraC(-) cultures phagocytose most dead neurons within 24 h without exacerbating neuronal loss or mounting a strong or sustained inflammatory response. LPS addition induces a robust inflammatory response, based on microglial expressions of TNF-α, COX-2 and iNOS proteins, and mRNAs, whereas these markers are essentially undetectable in control cultures. Thus, the functional effector state of microglia is primed for phagocytosis but not inflammation or cytotoxicity even after kainate exposure that triggers death in the majority of neurons. This model should prove useful in studying the progressive activation states of microglia and factors that promote their conversion to inflammatory and cytotoxic phenotypes.
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727
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Transcriptional programming of human macrophages: on the way to systems immunology. J Mol Med (Berl) 2015; 93:589-97. [PMID: 25877862 DOI: 10.1007/s00109-015-1286-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 03/09/2015] [Accepted: 03/12/2015] [Indexed: 12/13/2022]
Abstract
Many of the major common diseases such as atherosclerosis, diabetes, obesity, numerous autoimmune diseases, as well as neurodegenerative diseases such as Alzheimer's disease and many cancer types are characterised by a chronic inflammatory component termed sterile inflammation. Myeloid cells, particularly macrophages, are an important cellular component of chronic inflammation in these diseases. For almost all of these disease conditions, previous reports suggested that macrophages can exert either so-called pro-inflammatory or anti-inflammatory functions, thereby either fighting or feeding the disease. This apparent dichotomy of reactions of macrophages led to a dichotomous definition of macrophage activation classified as macrophage polarisation. However, analysis of large transcriptomics data derived from human and murine macrophages show that macrophage functions are shaped in a very tissue- and signal-input specific manner, allowing these cells to develop extremely specific functional programmes. Integrating global views on macrophage activation on the transcriptome, the epigenome, the proteome or the metabolome will finally lead to a data-driven approach to understand macrophage biology in context of major diseases. We are indeed on the way to a systems immunology approach that integrates -omics data with mathematical and bioinformatical modelling as the pre-requisite to generate data-driven hypotheses. This approach opens completely new avenues for the development of tailored diagnostics and therapies targeting macrophages in sterile inflammations of the major common diseases. I will also discuss some of the next developments that will be necessary to reach these important goals.
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728
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Schultze JL, Freeman T, Hume DA, Latz E. A transcriptional perspective on human macrophage biology. Semin Immunol 2015; 27:44-50. [PMID: 25843246 DOI: 10.1016/j.smim.2015.02.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 01/31/2015] [Accepted: 02/04/2015] [Indexed: 12/12/2022]
Abstract
Macrophages are a major cell type in tissue homeostasis and contribute to both pathology and resolution in all acute and chronic inflammatory diseases ranging from infections, cancer, obesity, atherosclerosis, autoimmune disorders to neurodegenerative diseases such as Alzheimer's disease. The cellular and functional diversity of macrophages depends upon tightly regulated transcription. The innate immune system is under profound evolutionary selection. There is increasing recognition that human macrophage biology differs very significantly from that of commonly studied animal models, which therefore can have a limited predictive value. Here we report on the newest findings on transcriptional control of macrophage activation, and how we envision integrating studies on transcriptional and epigenetic regulation, and more classical approaches in murine models. Moreover, we provide new insights into how we can learn about transcriptional regulation in the human system from larger efforts such as the FANTOM (Functional Annotation of the Mammalian Genome) consortium.
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Affiliation(s)
- Joachim L Schultze
- Genomics and Immunoregulation, LIMES-Institute, University of Bonn, 53115 Bonn, Germany.
| | - Tom Freeman
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh, Midlothian EH25 9RG, Scotland, UK
| | - David A Hume
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh, Midlothian EH25 9RG, Scotland, UK
| | - Eicke Latz
- Institute of Innate Immunity, University Hospitals, University of Bonn, 53127 Bonn, Germany; Division of Infectious Diseases and Immunology, UMass Medical School, Worcester, MA 01605, USA; German Center of Neurodegenerative Diseases (DZNE), 53175 Bonn, Germany
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729
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Verheijden S, Beckers L, Casazza A, Butovsky O, Mazzone M, Baes M. Identification of a chronic non-neurodegenerative microglia activation state in a mouse model of peroxisomal β-oxidation deficiency. Glia 2015; 63:1606-20. [PMID: 25846981 DOI: 10.1002/glia.22831] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 03/09/2015] [Accepted: 03/17/2015] [Indexed: 12/20/2022]
Abstract
The functional diversity and molecular adaptations of reactive microglia in the chronically inflamed central nervous system (CNS) are poorly understood. We previously showed that mice lacking multifunctional protein 2 (MFP2), a pivotal enzyme in peroxisomal β-oxidation, persistently accumulate reactive myeloid cells in the gray matter of the CNS. Here, we show that the increased numbers of myeloid cells solely derive from the proliferation of resident microglia and not from infiltrating monocytes. We defined the signature of Mfp2(-/-) microglia by gene expression profiling after acute isolation, which was validated by quantitative polymerase reaction (qPCR), immunohistochemical, and flow cytometric analysis. The features of Mfp2(-/-) microglia were compared with those from SOD1(G93A) mice, an amyotrophic lateral sclerosis model. In contrast to the neurodegenerative milieu of SOD1(G93A) spinal cord, neurons were intact in Mfp2(-/-) brain and Mfp2(-/-) microglia lacked signs of phagocytic and neurotoxic activity. The chronically reactive state of Mfp2(-/-) microglia was accompanied by the downregulation of markers that specify the unique microglial signature in homeostatic conditions. In contrast, mammalian target of rapamycin (mTOR) and downstream glycolytic and protein translation pathways were induced, indicative of metabolic adaptations. Mfp2(-/-) microglia were immunologically activated but not polarized to a pro- or anti-inflammatory phenotype. A peripheral lipopolysaccharide challenge provoked an exaggerated inflammatory response in Mfp2(-/-) brain, consistent with a primed state. Taken together, we demonstrate that chronic activation of resident microglia does not necessarily lead to phagocytosis nor overt neurotoxicity.
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Affiliation(s)
- Simon Verheijden
- Department of Pharmaceutical and Pharmacological Sciences, KU Leuven-University of Leuven, Cell Metabolism, Leuven, Belgium
| | - Lien Beckers
- Department of Pharmaceutical and Pharmacological Sciences, KU Leuven-University of Leuven, Cell Metabolism, Leuven, Belgium
| | - Andrea Casazza
- Department of Oncology, Laboratory of Molecular Oncology and Angiogenesis, KU Leuven-University of Leuven, Leuven, Belgium.,Laboratory of Molecular Oncology and Angiogenesis, VIB, Vesalius Research Center, Leuven, Belgium
| | - Oleg Butovsky
- Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Massimiliano Mazzone
- Department of Oncology, Laboratory of Molecular Oncology and Angiogenesis, KU Leuven-University of Leuven, Leuven, Belgium.,Laboratory of Molecular Oncology and Angiogenesis, VIB, Vesalius Research Center, Leuven, Belgium
| | - Myriam Baes
- Department of Pharmaceutical and Pharmacological Sciences, KU Leuven-University of Leuven, Cell Metabolism, Leuven, Belgium
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730
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The many roads to mitochondrial dysfunction in neuroimmune and neuropsychiatric disorders. BMC Med 2015; 13:68. [PMID: 25889215 PMCID: PMC4382850 DOI: 10.1186/s12916-015-0310-y] [Citation(s) in RCA: 159] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 03/04/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Mitochondrial dysfunction and defects in oxidative metabolism are a characteristic feature of many chronic illnesses not currently classified as mitochondrial diseases. Examples of such illnesses include bipolar disorder, multiple sclerosis, Parkinson's disease, schizophrenia, depression, autism, and chronic fatigue syndrome. DISCUSSION While the majority of patients with multiple sclerosis appear to have widespread mitochondrial dysfunction and impaired ATP production, the findings in patients diagnosed with Parkinson's disease, autism, depression, bipolar disorder schizophrenia and chronic fatigue syndrome are less consistent, likely reflecting the fact that these diagnoses do not represent a disease with a unitary pathogenesis and pathophysiology. However, investigations have revealed the presence of chronic oxidative stress to be an almost invariant finding in study cohorts of patients afforded each diagnosis. This state is characterized by elevated reactive oxygen and nitrogen species and/or reduced levels of glutathione, and goes hand in hand with chronic systemic inflammation with elevated levels of pro-inflammatory cytokines. SUMMARY This paper details mechanisms by which elevated levels of reactive oxygen and nitrogen species together with elevated pro-inflammatory cytokines could conspire to pave a major road to the development of mitochondrial dysfunction and impaired oxidative metabolism seen in many patients diagnosed with these disorders.
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731
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Cunningham C, Hennessy E. Co-morbidity and systemic inflammation as drivers of cognitive decline: new experimental models adopting a broader paradigm in dementia research. ALZHEIMERS RESEARCH & THERAPY 2015; 7:33. [PMID: 25802557 PMCID: PMC4369837 DOI: 10.1186/s13195-015-0117-2] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Dementia prevalence increases with age and Alzheimer’s disease (AD) accounts for up to 75% of cases. However, significant variability and overlap exists in the extent of amyloid-β and Tau pathology in AD and non-demented populations and it is clear that other factors must influence progression of cognitive decline, perhaps independent of effects on amyloid pathology. Coupled with the failure of amyloid-clearing strategies to provide benefits for AD patients, it seems necessary to broaden the paradigm in dementia research beyond amyloid deposition and clearance. Evidence has emerged from alternative animal model approaches as well as clinical and population epidemiological studies that co-morbidities contribute significantly to neurodegeneration/cognitive decline and systemic inflammation has been a strong common theme in these approaches. We hypothesise, and discuss in this review, that a disproportionate inflammatory response to infection, injury or chronic peripheral disease is a key determinant of cognitive decline. We propose that detailed study of alternative models, which encompass acute and chronic systemic inflammatory co-morbidities, is an important priority for the field and we examine the cognitive consequences of several of these alternative experimental approaches. Experimental models of severe sepsis in normal animals or moderate acute systemic inflammation in animals with existing neurodegenerative pathology have uncovered roles for inflammatory mediators interleukin-1β, tumour necrosis factor-α, inducible nitric oxide synthase, complement, prostaglandins and NADPH oxidase in inflammation-induced cognitive dysfunction and neuronal death. Moreover, microglia are primed by existing neurodegenerative pathology to produce exaggerated responses to subsequent stimulation with bacterial lipopolysaccharide or other inflammatory stimuli and these insults drive acute dysfunction and negatively affect disease trajectory. Chronic co-morbidities, such as arthritis, atherosclerosis, obesity and diabetes, are risk factors for subsequent dementia and those with high inflammatory status are particularly at risk. Models of chronic co-morbidities, and indeed low grade systemic inflammation in the absence of specific pathology, indicate that interleukin-1β, tumour necrosis factor-α and other inflammatory mediators drive insulin resistance, hypothalamic dysfunction, impaired neurogenesis and cognitive function and impact on functional decline. Detailed study of these pathways will uncover important mechanisms of peripheral inflammation-driven cognitive decline and are already driving clinical initiatives to mitigate AD progression through minimising systemic inflammation.
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Affiliation(s)
- Colm Cunningham
- Trinity College Institute of Neuroscience and School of Biochemistry and Immunology, Trinity College Dublin, Dublin 2, Republic of Ireland
| | - Edel Hennessy
- Trinity College Institute of Neuroscience and School of Biochemistry and Immunology, Trinity College Dublin, Dublin 2, Republic of Ireland
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732
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Terrando N, Yang T, Ryu JK, Newton PT, Monaco C, Feldmann M, Ma D, Akassoglou K, Maze M. Stimulation of the α7 nicotinic acetylcholine receptor protects against neuroinflammation after tibia fracture and endotoxemia in mice. Mol Med 2015; 20:667-75. [PMID: 25365546 DOI: 10.2119/molmed.2014.00143] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 10/29/2014] [Indexed: 01/06/2023] Open
Abstract
Surgery and critical illness often associate with cognitive decline. Surgical trauma or infection can lead independently to learning and memory impairments via similar, but not identical, cellular signaling of the innate immune system that promotes neuroinflammation. In this study we explored the putative synergism between aseptic orthopedic surgery and infection, the latter reproduced by postoperative lipopolysaccharide (LPS) administration. We observed that surgery and LPS augmented systemic inflammation up to postoperative d 3 and this was associated with further neuroinflammation (CD11b and CD68 immunoreactivity) in the hippocampus in mice compared with those receiving surgery or LPS alone. Administration of a selective α7 subtype nicotinic acetylcholine receptor (α7 nAChR) agonist 2 h after LPS significantly improved neuroinflammation and hippocampal-dependent memory dysfunction. Modulation of nuclear factor-kappa B (NF-κB) activation in monocytes and regulation of the oxidative stress response through nicotinamide adenine dinucleotide phosphate (NADPH) signaling appear to be key targets in modulating this response. Overall, these results suggest that it may be conceivable to limit and possibly prevent postoperative complications, including cognitive decline and/or infections, through stimulation of the cholinergic antiinflammatory pathway.
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Affiliation(s)
- Niccolò Terrando
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden.,Department of Anesthesia and Perioperative Care, UCSF Medical Center, San Francisco, California, United States of America
| | - Ting Yang
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden.,Department of Anesthesia and Perioperative Care, UCSF Medical Center, San Francisco, California, United States of America
| | - Jae Kyu Ryu
- Gladstone Institute of Neurological Disease, University of California San Francisco, San Francisco, California, United States of America
| | - Phillip T Newton
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden.,Department of Women's and Children's Health, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden
| | - Claudia Monaco
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, London, United Kingdom
| | - Marc Feldmann
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, London, United Kingdom
| | - Daqing Ma
- Anaesthetics, Pain Medicine and Intensive Care, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Chelsea & Westminster Hospital, London, United Kingdom
| | - Katerina Akassoglou
- Gladstone Institute of Neurological Disease, University of California San Francisco, San Francisco, California, United States of America.,Department of Neurology, University of California San Francisco, San Francisco, California, United States of America
| | - Mervyn Maze
- Department of Anesthesia and Perioperative Care, UCSF Medical Center, San Francisco, California, United States of America
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733
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Clarner T, Janssen K, Nellessen L, Stangel M, Skripuletz T, Krauspe B, Hess FM, Denecke B, Beutner C, Linnartz-Gerlach B, Neumann H, Vallières L, Amor S, Ohl K, Tenbrock K, Beyer C, Kipp M. CXCL10 Triggers Early Microglial Activation in the Cuprizone Model. THE JOURNAL OF IMMUNOLOGY 2015; 194:3400-13. [DOI: 10.4049/jimmunol.1401459] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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734
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Lourbopoulos A, Ertürk A, Hellal F. Microglia in action: how aging and injury can change the brain's guardians. Front Cell Neurosci 2015; 9:54. [PMID: 25755635 PMCID: PMC4337366 DOI: 10.3389/fncel.2015.00054] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 02/03/2015] [Indexed: 01/03/2023] Open
Abstract
Neuroinflammation, the inflammatory response in the central nervous system (CNS), is a major determinant of neuronal function and survival during aging and disease progression. Microglia, as the resident tissue-macrophages of the brain, provide constant support to surrounding neurons in healthy brain. Upon any stress signal (such as trauma, ischemia, inflammation) they are one of the first cells to react. Local and/or peripheral signals determine microglia stress response, which can vary within a continuum of states from beneficial to detrimental for neuronal survival, and can be shaped by aging and previous insults. In this review, we discuss the roles of microglia upon an ischemic or traumatic injury, and give our perspective how aging may contribute to microglia behavior in the injured brain. We speculate that a deeper understanding of specific microglia identities will pave the way to develop more potent therapeutics to treat the diseases of aging brain.
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Affiliation(s)
- Athanasios Lourbopoulos
- Laboratory of Experimental Stroke Research, Institute for Stroke and Dementia Research (ISD), University of Munich Medical School Munich, Germany
| | - Ali Ertürk
- Laboratory of Acute Brain Injury, Institute for Stroke and Dementia Research (ISD), University of Munich Medical School Munich, Germany
| | - Farida Hellal
- Laboratory of Experimental Stroke Research, Institute for Stroke and Dementia Research (ISD), University of Munich Medical School Munich, Germany
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735
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Activation status of human microglia is dependent on lesion formation stage and remyelination in multiple sclerosis. J Neuropathol Exp Neurol 2015; 74:48-63. [PMID: 25470347 DOI: 10.1097/nen.0000000000000149] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Similar to macrophages, microglia adopt diverse activation states and contribute to repair and tissue damage in multiple sclerosis. Using reverse transcription-quantitative polymerase chain reaction and immunohistochemistry, we show that in vitro M1-polarized (proinflammatory) human adult microglia express the distinctive markers CD74, CD40, CD86, and CCR7, whereas M2 (anti-inflammatory) microglia express mannose receptor and the anti-inflammatory cytokine CCL22. The expression of these markers was assessed in clusters of activated microglia in normal-appearing white matter (preactive lesions) and areas of remyelination, representing reparative multiple sclerosis lesions. We show that activated microglia in preactive and remyelinating lesions express CD74, CD40, CD86, and the M2 markers CCL22 and CD209, but not mannose receptor. To examine whether this intermediate microglia profile is static or dynamic and thus susceptible to changes in the microenvironment, we polarized microglia into M1 or M2 phenotype in vitro and then subsequently treated them with the opposing polarization regimen. These studies revealed that expression of CD40, CXCL10, and mannose receptor is dynamic and that microglia, like macrophages, can switch between M1 and M2 phenotypic profiles. Taken together, our data define the differential activation states of microglia during lesion development in multiple sclerosis-affected CNS tissues and underscore the plasticity of human adult microglia in vitro.
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736
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Dhama K, Kesavan M, Karthik K, . A, Tiwari R, Sunkara LT, Singh R. Neuroimmunomodulation Countering Various Diseases, Disorders, Infections, Stress and Aging. INT J PHARMACOL 2015. [DOI: 10.3923/ijp.2015.76.94] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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737
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738
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Correani V, Francesco LD, Cera I, Mignogna G, Giorgi A, Mazzanti M, Fumagalli L, Fabrizi C, Maras B, Schininà ME. Reversible redox modifications in the microglial proteome challenged by beta amyloid. MOLECULAR BIOSYSTEMS 2015; 11:1584-93. [DOI: 10.1039/c4mb00703d] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Reversible redox modifications of the microglial proteome contribute to switching of these neuronal sentinel cells toward a neuroinflammatory phenotype.
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Affiliation(s)
- Virginia Correani
- Dipartimento di Scienze Biochimiche
- Sapienza University of Rome
- 00185 Rome
- Italy
| | - Laura Di Francesco
- Dipartimento di Scienze Biochimiche
- Sapienza University of Rome
- 00185 Rome
- Italy
| | - Isabella Cera
- Dipartimento di Scienze Biochimiche
- Sapienza University of Rome
- 00185 Rome
- Italy
| | - Giuseppina Mignogna
- Dipartimento di Scienze Biochimiche
- Sapienza University of Rome
- 00185 Rome
- Italy
| | - Alessandra Giorgi
- Dipartimento di Scienze Biochimiche
- Sapienza University of Rome
- 00185 Rome
- Italy
| | - Michele Mazzanti
- Dipartimento di Bioscienze
- Università degli Studi di Milano
- Milan
- Italy
| | - Lorenzo Fumagalli
- Dipartimento di Scienze Anatomiche
- Istologiche
- Medico-Legali e dell'Apparato Locomotore
- Sapienza University of Rome
- Rome
| | - Cinzia Fabrizi
- Dipartimento di Scienze Anatomiche
- Istologiche
- Medico-Legali e dell'Apparato Locomotore
- Sapienza University of Rome
- Rome
| | - Bruno Maras
- Dipartimento di Scienze Biochimiche
- Sapienza University of Rome
- 00185 Rome
- Italy
| | - M. Eugenia Schininà
- Dipartimento di Scienze Biochimiche
- Sapienza University of Rome
- 00185 Rome
- Italy
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739
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Burokas A, Moloney RD, Dinan TG, Cryan JF. Microbiota regulation of the Mammalian gut-brain axis. ADVANCES IN APPLIED MICROBIOLOGY 2015; 91:1-62. [PMID: 25911232 DOI: 10.1016/bs.aambs.2015.02.001] [Citation(s) in RCA: 177] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The realization that the microbiota-gut-brain axis plays a critical role in health and disease has emerged over the past decade. The brain-gut axis is a bidirectional communication system between the central nervous system (CNS) and the gastrointestinal tract. Regulation of the microbiota-brain-gut axis is essential for maintaining homeostasis, including that of the CNS. The routes of this communication are not fully elucidated but include neural, humoral, immune, and metabolic pathways. A number of approaches have been used to interrogate this axis including the use of germ-free animals, probiotic agents, antibiotics, or animals exposed to pathogenic bacterial infections. Together, it is clear that the gut microbiota can be a key regulator of mood, cognition, pain, and obesity. Understanding microbiota-brain interactions is an exciting area of research which may contribute new insights into individual variations in cognition, personality, mood, sleep, and eating behavior, and how they contribute to a range of neuropsychiatric diseases ranging from affective disorders to autism and schizophrenia. Finally, the concept of psychobiotics, bacterial-based interventions with mental health benefit, is also emerging.
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Affiliation(s)
- Aurelijus Burokas
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
| | - Rachel D Moloney
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
| | - Timothy G Dinan
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland; Department of Psychiatry, University College Cork, Cork, Ireland
| | - John F Cryan
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
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740
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Patterson SL. Immune dysregulation and cognitive vulnerability in the aging brain: Interactions of microglia, IL-1β, BDNF and synaptic plasticity. Neuropharmacology 2014; 96:11-8. [PMID: 25549562 DOI: 10.1016/j.neuropharm.2014.12.020] [Citation(s) in RCA: 190] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 12/10/2014] [Accepted: 12/12/2014] [Indexed: 11/30/2022]
Abstract
Older individuals often experience declines in cognitive function after events (e.g. infection, or injury) that trigger activation of the immune system. This occurs at least in part because aging sensitizes the response of microglia (the brain's resident immune cells) to signals triggered by an immune challenge. In the aging brain, microglia respond to these signals by producing more pro-inflammatory cytokines (e.g. interleukin-1beta or IL-1β) and producing them for longer than microglia in younger brains. This exaggerated inflammatory response can compromise processes critical for optimal cognitive functioning. Interleukin-1β is central to the inflammatory response and is a key mediator and modulator of an array of associated biological functions; thus its production and release is usually very tightly regulated. This review will focus on the impact of dysregulated production of IL-1β on hippocampus dependent-memory systems and associated synaptic plasticity processes. The neurotrophin brain-derived neurotrophic factor (BNDF) helps to protect neurons from damage caused by infection or injury, and it plays a critical role in many of the same memory and hippocampal plasticity processes compromised by dysregulated production of IL-1β. This suggests that an exaggerated brain inflammatory response, arising from aging and a secondary immune challenge, may erode the capacity to provide the BDNF needed for memory-related plasticity processes at hippocampal synapses. This article is part of a Special Issue entitled 'Neuroimmunology and Synaptic Function'.
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Affiliation(s)
- Susan L Patterson
- Temple University, Biology Life Science Building, 1900 N. 12th Street, Philadelphia, PA, 19122, USA.
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Fan H, Gong N, Li TF, Ma AN, Wu XY, Wang MW, Wang YX. The non-peptide GLP-1 receptor agonist WB4-24 blocks inflammatory nociception by stimulating β-endorphin release from spinal microglia. Br J Pharmacol 2014; 172:64-79. [PMID: 25176008 DOI: 10.1111/bph.12895] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 08/19/2014] [Accepted: 08/22/2014] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND AND PURPOSE Two peptide agonists of the glucagon-like peptide-1 (GLP-1) receptor, exenatide and GLP-1 itself, exert anti-hypersensitive effects in neuropathic, cancer and diabetic pain. In this study, we have assessed the anti-allodynic and anti-hyperalgesic effects of the non-peptide agonist WB4-24 in inflammatory nociception and the possible involvement of microglial β-endorphin and pro-inflammatory cytokines. EXPERIMENTAL APPROACH We used rat models of inflammatory nociception induced by formalin, carrageenan or complete Freund's adjuvant (CFA), to test mechanical allodynia and thermal hyperalgesia. Expression of β-endorphin and pro-inflammatory cytokines was measured using real-time quantitative PCR and fluorescent immunoassays. KEY RESULTS WB4-24 displaced the specific binding of exendin (9-39) in microglia. Single intrathecal injection of WB4-24 (0.3, 1, 3, 10, 30 and 100 μg) exerted dose-dependent, specific, anti-hypersensitive effects in acute and chronic inflammatory nociception induced by formalin, carrageenan and CFA, with a maximal inhibition of 60-80%. Spinal WB4-24 was not effective in altering nociceptive pain. Subcutaneous injection of WB4-24 was also antinociceptive in CFA-treated rats. WB4-24 evoked β-endorphin release but did not inhibit expression of pro-inflammatory cytokines in either the spinal cord of CFA-treated rats or cultured microglia stimulated by LPS. WB4-24 anti-allodynia was prevented by a microglial inhibitor, β-endorphin antiserum and a μ-opioid receptor antagonist. CONCLUSIONS AND IMPLICATIONS Our results suggest that WB4-24 inhibits inflammatory nociception by releasing analgesic β-endorphin rather than inhibiting the expression of proalgesic pro-inflammatory cytokines in spinal microglia, and that the spinal GLP-1 receptor is a potential target molecule for the treatment of pain hypersensitivity including inflammatory nociception.
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Affiliation(s)
- Hui Fan
- King's Lab, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
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742
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Nemeth CL, Reddy R, Bekhbat M, Bailey J, Neigh GN. Microglial activation occurs in the absence of anxiety-like behavior following microembolic stroke in female, but not male, rats. J Neuroinflammation 2014; 11:174. [PMID: 25374157 PMCID: PMC4232723 DOI: 10.1186/s12974-014-0174-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 09/28/2014] [Indexed: 12/14/2022] Open
Abstract
Background The incidence of depression and anxiety disorders is twice as high in women than men; however, females exhibit less neuronal damage following an equivalent ischemic event. Microembolic stroke increases anxiety- and depressive-like behaviors in male rats but the behavioral repercussions in females are unknown. Findings Given the relative neuronal protection from stroke in ovary-intact females, female rats exposed to microembolic stroke may be behaviorally protected as compared to males. The data presented demonstrate that anxiety-like behavior is increased in males despite a comparable increase in microglial activation following microembolic stroke in both males and females. Conclusions These data suggest that males may be more behaviorally susceptible to the effects of microembolic stroke and further illustrate a dissociation between neuroinflammation and behavior in females.
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Affiliation(s)
- Christina L Nemeth
- Department of Psychiatry and Behavioral Science, Emory University, Atlanta, GA, USA. .,Department of Physiology, Emory University, Atlanta, GA, USA.
| | - Renuka Reddy
- Department of Physiology, Emory University, Atlanta, GA, USA.
| | - Mandakh Bekhbat
- Department of Physiology, Emory University, Atlanta, GA, USA.
| | - Jabari Bailey
- Department of Physiology, Emory University, Atlanta, GA, USA.
| | - Gretchen N Neigh
- Department of Psychiatry and Behavioral Science, Emory University, Atlanta, GA, USA. .,Department of Physiology, Emory University, Atlanta, GA, USA.
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743
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Toll-like receptors 2, -3 and -4 prime microglia but not astrocytes across central nervous system regions for ATP-dependent interleukin-1β release. Sci Rep 2014; 4:6824. [PMID: 25351234 PMCID: PMC5381369 DOI: 10.1038/srep06824] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 09/09/2014] [Indexed: 12/13/2022] Open
Abstract
Interleukin-1β (IL-1β) is a crucial mediator in the pathogenesis of inflammatory diseases at the periphery and in the central nervous system (CNS). Produced as an unprocessed and inactive pro-form which accumulates intracellularly, release of the processed cytokine is strongly promoted by ATP acting at the purinergic P2X7 receptor (P2X7R) in cells primed with lipopolysaccharide (LPS), a Toll-like receptor (TLR) 4 ligand. Microglia are central to the inflammatory process and a major source of IL-1β when activated. Here we show that purified (>99%) microglia cultured from rat cortex, spinal cord and cerebellum respond robustly to ATP-dependent IL-1β release, upon priming with a number of TLR isoform ligands (zymosan and Pam3CSK4 for TLR2, poly(I:C) for TLR3). Cytokine release was prevented by a P2X7R antagonist and inhibitors of stress-activated protein kinases. Enriched astrocytes (≤5% microglia) from these CNS regions displayed responses qualitatively similar to microglia but became unresponsive upon eradication of residual microglia with the lysosomotropic agent Leu-Leu-OMe. Activation of multiple TLR isoforms in nervous system pathology, coupled with elevated extracellular ATP levels and subsequent P2X7R activation may represent an important route for microglia-derived IL-1β. This phenomenon may have important consequences for neuroinflammation and its position to the common pathology of CNS diseases.
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744
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Maternal immune activation and abnormal brain development across CNS disorders. Nat Rev Neurol 2014; 10:643-60. [PMID: 25311587 DOI: 10.1038/nrneurol.2014.187] [Citation(s) in RCA: 595] [Impact Index Per Article: 59.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Epidemiological studies have shown a clear association between maternal infection and schizophrenia or autism in the progeny. Animal models have revealed maternal immune activation (mIA) to be a profound risk factor for neurochemical and behavioural abnormalities in the offspring. Microglial priming has been proposed as a major consequence of mIA, and represents a critical link in a causal chain that leads to the wide spectrum of neuronal dysfunctions and behavioural phenotypes observed in the juvenile, adult or aged offspring. Such diversity of phenotypic outcomes in the mIA model are mirrored by recent clinical evidence suggesting that infectious exposure during pregnancy is also associated with epilepsy and, to a lesser extent, cerebral palsy in children. Preclinical research also suggests that mIA might precipitate the development of Alzheimer and Parkinson diseases. Here, we summarize and critically review the emerging evidence that mIA is a shared environmental risk factor across CNS disorders that varies as a function of interactions between genetic and additional environmental factors. We also review ongoing clinical trials targeting immune pathways affected by mIA that may play a part in disease manifestation. In addition, future directions and outstanding questions are discussed, including potential symptomatic, disease-modifying and preventive treatment strategies.
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745
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Doorn KJ, Moors T, Drukarch B, van de Berg WDJ, Lucassen PJ, van Dam AM. Microglial phenotypes and toll-like receptor 2 in the substantia nigra and hippocampus of incidental Lewy body disease cases and Parkinson's disease patients. Acta Neuropathol Commun 2014; 2:90. [PMID: 25099483 PMCID: PMC4224021 DOI: 10.1186/s40478-014-0090-1] [Citation(s) in RCA: 134] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 07/19/2014] [Indexed: 01/08/2023] Open
Abstract
Next to α-synuclein deposition, microglial activation is a prominent pathological feature in the substantia nigra (SN) of Parkinson's disease (PD) patients. Little is known, however, about the different phenotypes of microglia and how they change during disease progression, in the SN or in another brain region, like the hippocampus (HC), which is implicated in dementia and depression, important non-motor symptoms in PD. We studied phenotypes and activation of microglia in the SN and HC of established PD patients (Braak PD stage 4–6), matched controls (Braak PD stage 0) and of incidental Lewy Body disease (iLBD) cases (Braak PD stage 1–3) that are considered a prodromal state of PD. As recent experimental studies suggested that toll-like receptor 2 (TLR2) mediates α-synuclein triggered microglial activation, we also studied whether TLR2 expression is indeed related to pathology in iLBD and PD patients. A clear α-synuclein pathology-related increase in amoeboid microglia was present in the HC and SN in PD. Also, morphologically primed/reactive microglial cells, and a profound increase in microglial TLR2 expression were apparent in iLBD, but not PD, cases, indicative of an early activational response to PD pathology. Moreover, TLR2 was differentially expressed between the SN and HC, consistent with a region-specific pattern of microglial activation. In conclusion, the regional changes in microglial phenotype and TLR2 expression in primed/reactive microglia in the SN and HC of iLBD cases indicate that TLR2 may play a prominent role in the microglial-mediated responses that could be important for PD progression.
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Bsibsi M, Peferoen LAN, Holtman IR, Nacken PJ, Gerritsen WH, Witte ME, van Horssen J, Eggen BJL, van der Valk P, Amor S, van Noort JM. Demyelination during multiple sclerosis is associated with combined activation of microglia/macrophages by IFN-γ and alpha B-crystallin. Acta Neuropathol 2014; 128:215-29. [PMID: 24997049 DOI: 10.1007/s00401-014-1317-8] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 06/27/2014] [Accepted: 06/27/2014] [Indexed: 01/08/2023]
Abstract
Activated microglia and macrophages play a key role in driving demyelination during multiple sclerosis (MS), but the factors responsible for their activation remain poorly understood. Here, we present evidence for a dual-trigger role of IFN-γ and alpha B-crystallin (HSPB5) in this context. In MS-affected brain tissue, accumulation of the molecular chaperone HSPB5 by stressed oligodendrocytes is a frequent event. We have shown before that this triggers a TLR2-mediated protective response in surrounding microglia, the molecular signature of which is widespread in normal-appearing brain tissue during MS. Here, we show that IFN-γ, which can be released by infiltrated T cells, changes the protective response of microglia and macrophages to HSPB5 into a robust pro-inflammatory classical response. Exposure of cultured microglia and macrophages to IFN-γ abrogated subsequent IL-10 induction by HSPB5, and strongly promoted HSPB5-triggered release of TNF-α, IL-6, IL-12, IL-1β and reactive oxygen and nitrogen species. In addition, high levels of CXCL9, CXCL10, CXL11, several guanylate-binding proteins and the ubiquitin-like protein FAT10 were induced by combined activation with IFN-γ and HSPB5. As immunohistochemical markers for microglia and macrophages exposed to both IFN-γ and HSPB5, these latter factors were found to be selectively expressed in inflammatory infiltrates in areas of demyelination during MS. In contrast, they were absent from activated microglia in normal-appearing brain tissue. Together, our data suggest that inflammatory demyelination during MS is selectively associated with IFN-γ-induced re-programming of an otherwise protective response of microglia and macrophages to the endogenous TLR2 agonist HSPB5.
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Affiliation(s)
- Malika Bsibsi
- Delta Crystallon, Zernikedreef 9, 2333, CK Leiden, The Netherlands
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Persson AK, Estacion M, Ahn H, Liu S, Stamboulian-Platel S, Waxman SG, Black JA. Contribution of sodium channels to lamellipodial protrusion and Rac1 and ERK1/2 activation in ATP-stimulated microglia. Glia 2014; 62:2080-95. [PMID: 25043721 DOI: 10.1002/glia.22728] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 06/11/2014] [Accepted: 07/08/2014] [Indexed: 12/19/2022]
Abstract
Microglia are motile resident immune cells of the central nervous system (CNS) that continuously explore their territories for threats to tissue homeostasis. Following CNS insult (e.g., cellular injury, infection, or ischemia), microglia respond to signals such as ATP, transform into an activated state, and migrate towards the threat. Directed migration is a complex and highly-coordinated process involving multiple intersecting cellular pathways, including signal transduction, membrane adhesion and retraction, cellular polarization, and rearrangement of cytoskeletal elements. We previously demonstrated that the activity of sodium channels contributes to ATP-induced migration of microglia. Here we show that TTX-sensitive sodium channels, specifically NaV 1.6, participate in an initial event in the migratory process, i.e., the formation in ATP-stimulated microglia of polymerized actin-rich membrane protrusions, lamellipodia, containing accumulations of Rac1 and phosphorylated ERK1/2. We also examined Ca(2+) transients in microglia and found that blockade of sodium channels with TTX produced a downward shift in the level of [Ca(2+) ]i during the delayed, slower recovery of [Ca(2+) ]i following ATP stimulation. These observations demonstrate a modulatory role of sodium channels on Ca(2+) transients in microglia that are likely to affect down-stream signaling cascades. Consistent with these observations, we demonstrate that ATP-induced microglial migration is mediated via Rac1 and ERK1/2, but not p38α/β and JNK, dependent pathways, and that activation of both Rac1 and ERK1/2 is modulated by sodium channel activity. Our results provide evidence for a direct link between sodium channel activity and modulation of Rac1 and ERK1/2 activation in ATP-stimulated microglia, possibly by regulating Ca(2+) transients.
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Affiliation(s)
- Anna-Karin Persson
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; Rehabilitation Research Center, VA Connecticut Healthcare System, West Haven, Connecticut
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Zheng X, Zhang X, Kang A, Ran C, Wang G, Hao H. Thinking outside the brain for cognitive improvement: Is peripheral immunomodulation on the way? Neuropharmacology 2014; 96:94-104. [PMID: 24978103 DOI: 10.1016/j.neuropharm.2014.06.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2014] [Revised: 06/16/2014] [Accepted: 06/19/2014] [Indexed: 02/07/2023]
Abstract
Cognitive impairment is a devastating condition commonly observed with normal aging and neurodegenerative disorders such as Alzheimer's Disease (AD). Although major efforts to prevent or slow down cognitive decline are largely focused within the central nervous system (CNS), it has become clear that signals from the systemic milieu are closely associated with the dysfunctional brain. In particular, the bidirectional crosstalk between the CNS and peripheral immune system plays a decisive role in shaping neuronal survival and function via neuroimmune, neuroendocrinal and bioenergetic mechanisms. Importantly, it is emerging that some neuroprotective and cognition-strengthening drugs may work by targeting the brain-periphery interactions, which could be intriguingly achieved without entering the CNS. We describe here how recent advances in dissecting cognitive deficits from a systems-perspective have contributed to a non-neurocentric understanding of its pathogenesis and treatment strategy. We also discuss the therapeutic and diagnostic implications of these exciting progresses and consider some key issues in the clinical translation. This article is part of a Special Issue entitled 'Neuroimmunology and Synaptic Function'.
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Affiliation(s)
- Xiao Zheng
- Nanjing University of Chinese Medicine Affiliated Hospital, Nanjing 210029, China; State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China.
| | - Xueli Zhang
- Zhong Da Hospital, Southeast University, Nanjing 210009, China
| | - An Kang
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Chongzhao Ran
- MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston 02129, United States
| | - Guangji Wang
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China
| | - Haiping Hao
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China.
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749
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Zhao QF, Yu JT, Tan MS, Tan L. ABCA7 in Alzheimer's Disease. Mol Neurobiol 2014; 51:1008-16. [PMID: 24878767 DOI: 10.1007/s12035-014-8759-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Accepted: 05/21/2014] [Indexed: 12/20/2022]
Abstract
ATP-binding cassette A7 (ABCA7) gene has recently been identified as a strong genetic locus associated with late-onset Alzheimer's disease (LOAD) through genome-wide association studies (GWASs). ABCA7 is a member of the ATP-binding cassette (ABC) transporter gene superfamily, which codes for 49 ABC proteins, divided into 7 subfamilies (coded A-G). As a multispan transmembrane protein, ABCA7 is most abundantly expressed in the microglial cells in the brain. The levels of ABCA7 have been detected to be increased in the Alzheimer's disease (AD) brain, which positively correlated with amyloid plaque burden and disease severity. Emerging data suggests that ABCA7 could be associated with AD via various pathways, possibly including amyloid-β (Aβ) accumulation, lipid metabolism, and phagocytosis. In this review, we summarize the known functions of ABCA7 and discuss the single-nucleotide polymorphisms (SNPs) related to LOAD, as well as their potential physiological effects. Finally, given the contributions of ABCA7 to AD pathogenesis, targeting ABCA7 might provide novel opportunities for AD therapy.
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Affiliation(s)
- Qing-Fei Zhao
- Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, China
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750
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Gomez-Nicola D, Perry VH. Microglial dynamics and role in the healthy and diseased brain: a paradigm of functional plasticity. Neuroscientist 2014; 21:169-84. [PMID: 24722525 PMCID: PMC4412879 DOI: 10.1177/1073858414530512] [Citation(s) in RCA: 219] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The study of the dynamics and functions of microglia in the healthy and diseased brain is a matter of intense scientific activity. The application of new techniques and new experimental approaches has allowed the identification of novel microglial functions and the redefinition of classic ones. In this review, we propose the study of microglial functions, rather than their molecular profiles, to better understand and define the roles of these cells in the brain. We review current knowledge on the role of surveillant microglia, proliferating microglia, pruning/neuromodulatory microglia, phagocytic microglia, and inflammatory microglia and the molecular profiles that are associated with these functions. In the remodeling scenario of microglial biology, the analysis of microglial functional states will inform about the roles in health and disease and will guide us to a more precise understanding of the multifaceted roles of this never-resting cells.
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Affiliation(s)
- Diego Gomez-Nicola
- Centre for Biological Sciences, University of Southampton, Southampton, UK
| | - V Hugh Perry
- Centre for Biological Sciences, University of Southampton, Southampton, UK
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