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Grieco M, Giorgi A, Giacovazzo G, Maggiore A, Ficchì S, d'Erme M, Mosca L, Mignogna G, Maras B, Coccurello R. β-Hexachlorocyclohexane triggers neuroinflammatory activity, epigenetic histone post-translational modifications and cognitive dysfunction. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 279:116487. [PMID: 38810285 DOI: 10.1016/j.ecoenv.2024.116487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 05/06/2024] [Accepted: 05/18/2024] [Indexed: 05/31/2024]
Abstract
Persistent organic pollutants (POPs), which encompass pesticides and industrial chemicals widely utilized across the globe, pose a covert threat to human health. β-hexachlorocyclohexane (β-HCH) is an organochlorine pesticide with striking stability, still illegally dumped in many countries, and recognized as responsible for several pathogenetic mechanisms. This study represents a pioneering exploration into the neurotoxic effects induced by the exposure to β-HCH specifically targeting neuronal cells (N2a), microglia (BV-2), and C57BL/6 mice. As shown by western blot and qPCR analyses, the administration of β-HCH triggered a modulation of NF-κB, a key factor influencing both inflammation and pro-inflammatory cytokines expression. We demonstrated by proteomic and western blot techniques epigenetic modifications in H3 histone induced by β-HCH. Histone acetylation of H3K9 and H3K27 increased in N2a, and in the prefrontal cortex of C57BL/6 mice administered with β-HCH, whereas it decreased in BV-2 cells and in the hippocampus. We also observed a severe detrimental effect on recognition memory and spatial navigation by the Novel Object Recognition Test (NORT) and the Object Place Recognition Task (OPRT) behavioural tests. Cognitive impairment was linked to decreased expression of the genes BDNF and SNAP-25, which are mediators involved in synaptic function and activity. The obtained results expand our understanding of the harmful impact produced by β-HCH exposure by highlighting its implication in the pathogenesis of neurological diseases. These findings will support intervention programs to limit the risk induced by exposure to POPs. Regulatory agencies should block further illicit use, causing environmental hazards and endangering human and animal health.
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Affiliation(s)
- Maddalena Grieco
- Department of Biochemical Sciences, Sapienza University, Rome, Italy
| | - Alessandra Giorgi
- Department of Biochemical Sciences, Sapienza University, Rome, Italy
| | - Giacomo Giacovazzo
- European Center for Brain Research, Santa Lucia Foundation IRCCS, Rome, Italy
| | - Anna Maggiore
- Department of Biochemical Sciences, Sapienza University, Rome, Italy; Department of Brain Sciences, Imperial College, London, UK
| | - Serena Ficchì
- Department of Biochemical Sciences, Sapienza University, Rome, Italy
| | - Maria d'Erme
- Department of Biochemical Sciences, Sapienza University, Rome, Italy
| | - Luciana Mosca
- Department of Biochemical Sciences, Sapienza University, Rome, Italy
| | | | - Bruno Maras
- Department of Biochemical Sciences, Sapienza University, Rome, Italy.
| | - Roberto Coccurello
- European Center for Brain Research, Santa Lucia Foundation IRCCS, Rome, Italy; Institute for Complex Systems, National Research Council (CNR), Roma, Italy
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2
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β-Adrenoceptor Blockade Moderates Neuroinflammation in Male and Female EAE Rats and Abrogates Sexual Dimorphisms in the Major Neuroinflammatory Pathways by Being More Efficient in Males. Cell Mol Neurobiol 2023; 43:1237-1265. [PMID: 35798933 DOI: 10.1007/s10571-022-01246-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 06/18/2022] [Indexed: 11/03/2022]
Abstract
Our previous studies showed more severe experimental autoimmune encephalomyelitis (EAE) in male compared with female adult rats, and moderating effect of propranolol-induced β-adrenoceptor blockade on EAE in females, the effect associated with transcriptional stimulation of Nrf2/HO-1 axis in spinal cord microglia. This study examined putative sexual dimorphism in propranolol action on EAE severity. Propranolol treatment beginning from the onset of clinical EAE mitigated EAE severity in rats of both sexes, but to a greater extent in males exhibiting higher noradrenaline levels and myeloid cell β2-adrenoceptor expression in spinal cord. This correlated with more prominent stimulatory effects of propranolol not only on CX3CL1/CX3CR1/Nrf2/HO-1 cascade, but also on Stat3/Socs3 signaling axis in spinal cord microglia/myeloid cells (mirrored in the decreased Stat3 and the increased Socs3 expression) from male rats compared with their female counterparts. Propranolol diminished the frequency of activated cells among microglia, increased their phagocyting/endocyting capacity, and shifted cytokine secretory profile of microglia/blood-borne myeloid cells towards an anti-inflammatory/neuroprotective phenotype. Additionally, it downregulated the expression of chemokines (CCL2, CCL19/21) driving T-cell/monocyte trafficking into spinal cord. Consequently, in propranolol-treated rats fewer activated CD4+ T cells and IL-17+ T cells, including CD4+IL17+ cells coexpressing IFN-γ/GM-CSF, were recovered from spinal cord of propranolol-treated rats compared with sex-matched saline-injected controls. All the effects of propranolol were more prominent in males. The study as a whole disclosed that sexual dimorphism in multiple molecular mechanisms implicated in EAE development may be responsible for greater severity of EAE in male rats and sexually dimorphic action of substances affecting them. Propranolol moderated EAE severity more effectively in male rats, exhibiting greater spinal cord noradrenaline (NA) levels and myeloid cell β2-adrenoceptor (β2-AR) expression than females. Propranolol affected CX3CR1/Nrf2/HO-1 and Stat3/Socs3 signaling axes in myeloid cells, favored their anti-inflammatory/neuroprotective phenotype and, consequently, reduced Th cell reactivation and differentiation into highly pathogenic IL-17/IFN-γ/GM-CSF-producing cells.
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3
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Singh D. Astrocytic and microglial cells as the modulators of neuroinflammation in Alzheimer's disease. J Neuroinflammation 2022; 19:206. [PMID: 35978311 PMCID: PMC9382837 DOI: 10.1186/s12974-022-02565-0] [Citation(s) in RCA: 92] [Impact Index Per Article: 46.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 08/06/2022] [Indexed: 12/17/2022] Open
Abstract
Neuroinflammation is instigated by the misfiring of immune cells in the central nervous system (CNS) involving microglia and astrocytes as key cell-types. Neuroinflammation is a consequence of CNS injury, infection, toxicity, or autoimmunity. It is favorable as well as a detrimental process for neurodevelopment and associated processes. Transient activation of inflammatory response involving release of cytokines and growth factors positively affects the development and post-injury tissue. However, chronic or uncontrolled inflammatory responses may lead to various neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis, and multiple sclerosis. These diseases have variable clinical and pathological features, but are underlaid by the aggregation of misfolded proteins with a cytotoxic effect. Notably, abnormal activation of glial cells could mediate neuroinflammation, leading to the neurodegenerative condition. Microglia, a type of glial cell, a resident immune cell, form the forefront defense of the CNS immune system. Dysfunctional microglia and astrocyte, a different kind of glial cell with homeostatic function, impairs the protein aggregate (amyloid-beta plaque) clearance in AD. Studies have shown that microglia and astrocytes undergo alterations in their genetic profile, cellular and molecular responses, and thus promote dysfunctional immune cross-talk in AD. Hence, targeting microglia and astrocytes-driven molecular pathways could resolve the particular layers of neuroinflammation and set a reliable therapeutic intervention in AD progression.
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Affiliation(s)
- Deepali Singh
- National Brain Research Centre, Manesar, Haryana, 122052, India.
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4
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Recasens M, Shrivastava K, Almolda B, González B, Castellano B. Astrocyte-targeted IL-10 production decreases proliferation and induces a downregulation of activated microglia/macrophages after PPT. Glia 2018; 67:741-758. [PMID: 30548340 DOI: 10.1002/glia.23573] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 11/06/2018] [Accepted: 11/12/2018] [Indexed: 01/03/2023]
Abstract
When central nervous system (CNS) homeostasis is altered, microglial cells become rapidly activated, proliferate and release a broad range of molecules. Among the plethora of molecules involved in the regulation of microglial activation, cytokines are considered crucial. Although production of interleukin-10 (IL-10) has been demonstrated after different types of CNS injuries and associated with protective functions, the specific role played by IL-10 modulating microglial cells remains unclear. Hence, the objective of this study was to evaluate the effects of transgenic astrocyte IL-10 production on microglial activation associated with axonal anterograde degeneration. To address it, the hippocampal area subjected to perforant pathway transection (PPT) was analyzed by immunohistochemistry (IHC), flow cytometry and protein microarray in transgenic (GFAP-IL10Tg) mice and their corresponding wild types (WT) littermates. Our results demonstrated increased microglial/macrophages density in nonlesioned and PPT-lesioned GFAP-IL10Tg animals when compared with nonlesioned and lesioned WT, respectively. This increase was not due to proliferation, as GFAP-IL10Tg mice showed a reduced proliferation of microglial cells, but was related to an increased population of CD11b+/CD45high monocyte/macrophages. Despite this higher number, the microglia/macrophage population in transgenic animals displayed a downregulated phenotype characterized by lower MHCII, ICOSL, and CD11c. Moreover, a sustained T-cell infiltration was found in transgenic animals. We strongly suggest these modifications must be associated with indirect effects derived from the influence of IL-10 on astrocytes and/or neurons, which express IL-10R. We finally suggested that TGF-β produced by astrocytes, along with IL-2 and CXCL10 might be crucial molecules mediating the effects of transgenic IL-10.
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Affiliation(s)
- Mireia Recasens
- Department of Cell Biology, Physiology and Immunology, Institute of Neuroscience, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Kalpana Shrivastava
- Department of Cell Biology, Physiology and Immunology, Institute of Neuroscience, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Beatriz Almolda
- Department of Cell Biology, Physiology and Immunology, Institute of Neuroscience, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Berta González
- Department of Cell Biology, Physiology and Immunology, Institute of Neuroscience, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Bernardo Castellano
- Department of Cell Biology, Physiology and Immunology, Institute of Neuroscience, Universitat Autònoma de Barcelona, Barcelona, Spain
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5
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Chun H, Marriott I, Lee CJ, Cho H. Elucidating the Interactive Roles of Glia in Alzheimer's Disease Using Established and Newly Developed Experimental Models. Front Neurol 2018; 9:797. [PMID: 30319529 PMCID: PMC6168676 DOI: 10.3389/fneur.2018.00797] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 09/04/2018] [Indexed: 12/21/2022] Open
Abstract
Alzheimer's disease (AD) is an irreversible neurodegenerative illness and the exact etiology of the disease remains unknown. It is characterized by long preclinical and prodromal phases with pathological features including an accumulation of amyloid-beta (Aβ) peptides into extracellular Aβ plaques in the brain parenchyma and the formation of intracellular neurofibrillary tangles (NFTs) within neurons as a result of abnormal phosphorylation of microtubule-associated tau proteins. In addition, prominent activation of innate immune cells is also observed and/or followed by marked neuroinflammation. While such neuroinflammatory responses may function in a neuroprotective manner by clearing neurotoxic factors, they can also be neurotoxic by contributing to neurodegeneration via elevated levels of proinflammatory mediators and oxidative stress, and altered levels of neurotransmitters, that underlie pathological symptoms including synaptic and cognitive impairment, neuronal death, reduced memory, and neocortex and hippocampus malfunctions. Glial cells, particularly activated microglia and reactive astrocytes, appear to play critical and interactive roles in such dichotomous responses. Accumulating evidences clearly point to their critical involvement in the prevention, initiation, and progression, of neurodegenerative diseases, including AD. Here, we review recent findings on the roles of astrocyte-microglial interactions in neurodegeneration in the context of AD and discuss newly developed in vitro and in vivo experimental models that will enable more detailed analysis of glial interplay. An increased understanding of the roles of glia and the development of new exploratory tools are likely to be crucial for the development of new interventions for early stage AD prevention and cures.
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Affiliation(s)
- Heejung Chun
- Center for Glia-Neuron Interaction, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea
| | - Ian Marriott
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, United States
| | - C Justin Lee
- Center for Glia-Neuron Interaction, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea.,Bio-Med, University of Science and Technology, Daejeon, South Korea
| | - Hansang Cho
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, United States.,Department of Mechanical Engineering and Engineering Science, University of North Carolina at Charlotte, Charlotte, NC, United States.,Center for Biomedical Engineering and Science, University of North Carolina at Charlotte, Charlotte, NC, United States.,The Nanoscale Science Program, University of North Carolina at Charlotte, Charlotte, NC, United States
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6
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Martin M, Deussen A. Effects of natural peptides from food proteins on angiotensin converting enzyme activity and hypertension. Crit Rev Food Sci Nutr 2017; 59:1264-1283. [PMID: 29244531 DOI: 10.1080/10408398.2017.1402750] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Cardiovascular diseases are the leading cause of death. The underlying pathophysiology is largely contributed by an overactivation of the renin-angiotensin-aldosterone-system (RAAS). Herein, angiotensin II (AngII) is a key mediator not only in blood pressure control and vascular tone regulation, but also involved in inflammation, endothelial dysfunction, atherosclerosis, hypertension and congestive heart failure. Since more than three decades suppression of AngII generation by inhibition of the angiotensin-converting enzyme (ACE) or blockade of the AngII-receptor has shown clinical benefit by reducing hypertension, atherosclerosis and other inflammation-associated cardiovascular diseases. Besides pharmaceutical ACE-inhibitors some natural peptides derived from food proteins reduce in vitro ACE activity. Several animal studies and a few human clinical trials have shown antihypertensive effects of such peptides, which might be attractive as food additives to prevent age-related RAAS activation. However, their inhibitory potency on in vitro ACE activity does not always correlate with an antihypertensive impact. While some peptides with high inhibitory activity on ACE-activity in vitro show no antihypertensive effect in vivo, other peptides with only a moderate ACE inhibitory activity in vitro cause such effects. The explanation for this conflicting phenomenon between inhibitory activity and antihypertensive effect remains unclear to date. This review shall critically address the effects of natural peptides derived from different food proteins on the cardiovascular system and the possible underlying mechanisms. A central aspect will be to point to conceptual gaps in the current understanding of the action of these peptides with respect to in vivo blood pressure lowering effects.
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Affiliation(s)
- Melanie Martin
- a Institute of Physiology, Medical Faculty Carl Gustav Carus, Technische Universität Dresden , Germany
| | - Andreas Deussen
- a Institute of Physiology, Medical Faculty Carl Gustav Carus, Technische Universität Dresden , Germany
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7
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Eyüpoglu IY, Savaskan NE. Epigenetics in Brain Tumors: HDACs Take Center Stage. Curr Neuropharmacol 2016; 14:48-54. [PMID: 26521944 PMCID: PMC4787285 DOI: 10.2174/1570159x13666151030162457] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 06/22/2015] [Accepted: 10/12/2015] [Indexed: 12/14/2022] Open
Abstract
Primary tumors of the brain account for 2 % of all cancers with malignant gliomas taking the lion’s share at 70 %. Malignant gliomas (high grade gliomas WHO° III and °IV) belong to one of the most threatening tumor entities known for their disappointingly short median survival time of just 14 months despite maximum therapy according to current gold standards. Malignant gliomas manifest various factors, through which they adapt and manipulate the tumor microenvironment to their advantage. Epigenetic mechanisms operate on the tumor microenvironment by de- and methylation processes and imbalances between the histone deacetylases (HDAC) and histone acetylases (HAT). Many compounds have been discovered modulating epigenetically controlled signals. Recent studies indicate that xCT (system xc-, SLC7a11) and CD44 (H-CAM, ECM-III, HUTCH-1) functions as a bridge between these epigenetic regulatory mechanisms and malignant glioma progression. The question that ensues is the extent to which therapeutic intervention on these signaling pathways would exert influence on the treatment of malignant gliomas as well as the extent to which manipulation of HDAC activity can sensitize tumor cells for chemotherapeutics through ‘epigenetic priming’. In light of considering the current stagnation in the development of therapeutic options, the need for new strategies in the treatment of gliomas has never been so pressing. In this context the possibility of pharmacological intervention on tumor-associated genes by epigenetic priming opens a novel path in the treatment of primary brain tumors.
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Affiliation(s)
- Ilker Y Eyüpoglu
- Department of Neurosurgery, Universitätsklinikum Erlangen, University of Erlangen- Nürnberg, Schwabachanlage 6, 91054 Erlangen, Germany.
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8
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Ghoochani A, Schwarz MA, Yakubov E, Engelhorn T, Doerfler A, Buchfelder M, Bucala R, Savaskan NE, Eyüpoglu IY. MIF-CD74 signaling impedes microglial M1 polarization and facilitates brain tumorigenesis. Oncogene 2016; 35:6246-6261. [PMID: 27157615 DOI: 10.1038/onc.2016.160] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 12/17/2015] [Accepted: 02/23/2016] [Indexed: 12/28/2022]
Abstract
Microglial cells in the brain tumor microenvironment are associated with enhanced glioma malignancy. They persist in an immunosuppressive M2 state at the peritumoral site and promote the growth of gliomas. Here, we investigated the underlying factors contributing to the abolished immune surveillance. We show that brain tumors escape pro-inflammatory M1 conversion of microglia via CD74 activation through the secretion of the cytokine macrophage migration inhibitory factor (MIF), which results in a M2 shift of microglial cells. Interruption of this glioma-microglial interaction through an antibody-neutralizing approach or small interfering RNA (siRNA)-mediated inhibition prolongs survival time in glioma-implanted mice by reinstating the microglial pro-inflammatory M1 function. We show that MIF-CD74 signaling inhibits interferon (IFN)-γ secretion in microglia through phosphorylation of microglial ERK1/2 (extracellular signal-regulated protein kinases 1 and 2). The inhibition of MIF signaling or its receptor CD74 promotes IFN-γ release and amplifies tumor death either through pharmacological inhibition or through siRNA-mediated knockdown. The reinstated IFN-γ secretion leads both to direct inhibition of glioma growth as well as inducing a M2 to M1 shift in glioma-associated microglia. Our data reveal that interference with the MIF signaling pathway represents a viable therapeutic option for the restoration of IFN-γ-driven immune surveillance.
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Affiliation(s)
- A Ghoochani
- Department of Neurosurgery, Universitätsklinikum Erlangen, Medical Faculty of the Friedrich Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - M A Schwarz
- Department of Neurosurgery, Universitätsklinikum Erlangen, Medical Faculty of the Friedrich Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - E Yakubov
- Department of Neurosurgery, Universitätsklinikum Erlangen, Medical Faculty of the Friedrich Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - T Engelhorn
- Department of Neuroradiology, Universitätsklinikum Erlangen, Medical Faculty of the Friedrich Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - A Doerfler
- Department of Neuroradiology, Universitätsklinikum Erlangen, Medical Faculty of the Friedrich Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - M Buchfelder
- Department of Neurosurgery, Universitätsklinikum Erlangen, Medical Faculty of the Friedrich Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - R Bucala
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - N E Savaskan
- Department of Neurosurgery, Universitätsklinikum Erlangen, Medical Faculty of the Friedrich Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany.,BiMECON Ent., Kurfürstenstrasse 21, Berlin, Germany
| | - I Y Eyüpoglu
- Department of Neurosurgery, Universitätsklinikum Erlangen, Medical Faculty of the Friedrich Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
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9
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Schartz ND, Herr SA, Madsen L, Butts SJ, Torres C, Mendez LB, Brewster AL. Spatiotemporal profile of Map2 and microglial changes in the hippocampal CA1 region following pilocarpine-induced status epilepticus. Sci Rep 2016; 6:24988. [PMID: 27143585 PMCID: PMC4855223 DOI: 10.1038/srep24988] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 04/06/2016] [Indexed: 01/01/2023] Open
Abstract
Status epilepticus (SE) triggers pathological changes to hippocampal dendrites that may promote epileptogenesis. The microtubule associated protein 2 (Map2) helps stabilize microtubules of the dendritic cytoskeleton. Recently, we reported a substantial decline in Map2 that coincided with robust microglia accumulation in the CA1 hippocampal region after an episode of SE. A spatial correlation between Map2 loss and reactive microglia was also reported in human cortex from refractory epilepsy. New evidence supports that microglia modulate dendritic structures. Thus, to identify a potential association between SE-induced Map2 and microglial changes, a spatiotemporal profile of these events is necessary. We used immunohistochemistry to determine the distribution of Map2 and the microglia marker IBA1 in the hippocampus after pilocarpine-induced SE from 4 hrs to 35 days. We found a decline in Map2 immunoreactivity in the CA1 area that reached minimal levels at 14 days post-SE and partially increased thereafter. In contrast, maximal microglia accumulation occurred in the CA1 area at 14 days post-SE. Our data indicate that SE-induced Map2 and microglial changes parallel each other’s spatiotemporal profiles. These findings may lay the foundation for future mechanistic studies to help identify potential roles for microglia in the dendritic pathology associated with SE and epilepsy.
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Affiliation(s)
- Nicole D Schartz
- Department of Psychological Sciences, West Lafayette, IN 47907, USA
| | - Seth A Herr
- Department of Psychological Sciences, West Lafayette, IN 47907, USA
| | - Lauren Madsen
- Department of Psychological Sciences, West Lafayette, IN 47907, USA
| | - Sarah J Butts
- Department of Psychological Sciences, West Lafayette, IN 47907, USA
| | - Ceidy Torres
- School of Science and Technology, Universidad del Este, Carolina, PR 00984, Puerto Rico
| | - Loyda B Mendez
- School of Science and Technology, Universidad del Este, Carolina, PR 00984, Puerto Rico
| | - Amy L Brewster
- Department of Psychological Sciences, West Lafayette, IN 47907, USA.,Weldon School of Biomedical Engineering, West Lafayette, IN 47907, USA
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10
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Lorea-Hernández JJ, Morales T, Rivera-Angulo AJ, Alcantara-Gonzalez D, Peña-Ortega F. Microglia modulate respiratory rhythm generation and autoresuscitation. Glia 2015; 64:603-19. [DOI: 10.1002/glia.22951] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Revised: 11/18/2015] [Accepted: 11/18/2015] [Indexed: 12/21/2022]
Affiliation(s)
- Jonathan-Julio Lorea-Hernández
- Departamento de Neurobiología del Desarrollo y Neurofisiología; Instituto De Neurobiología, UNAM Campus Juriquilla; Querétaro México
| | - Teresa Morales
- Departamento de Neurobiología del Desarrollo y Neurofisiología; Instituto De Neurobiología, UNAM Campus Juriquilla; Querétaro México
| | - Ana-Julia Rivera-Angulo
- Departamento de Neurobiología del Desarrollo y Neurofisiología; Instituto De Neurobiología, UNAM Campus Juriquilla; Querétaro México
| | - David Alcantara-Gonzalez
- Departamento de Neurobiología del Desarrollo y Neurofisiología; Instituto De Neurobiología, UNAM Campus Juriquilla; Querétaro México
| | - Fernando Peña-Ortega
- Departamento de Neurobiología del Desarrollo y Neurofisiología; Instituto De Neurobiología, UNAM Campus Juriquilla; Querétaro México
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11
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von Bernhardi R, Cornejo F, Parada GE, Eugenín J. Role of TGFβ signaling in the pathogenesis of Alzheimer's disease. Front Cell Neurosci 2015; 9:426. [PMID: 26578886 PMCID: PMC4623426 DOI: 10.3389/fncel.2015.00426] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Accepted: 10/09/2015] [Indexed: 12/19/2022] Open
Abstract
Aging is the main risk factor for Alzheimer’s disease (AD); being associated with conspicuous changes on microglia activation. Aged microglia exhibit an increased expression of cytokines, exacerbated reactivity to various stimuli, oxidative stress, and reduced phagocytosis of β-amyloid (Aβ). Whereas normal inflammation is protective, it becomes dysregulated in the presence of a persistent stimulus, or in the context of an inflammatory environment, as observed in aging. Thus, neuroinflammation can be a self-perpetuating deleterious response, becoming a source of additional injury to host cells in neurodegenerative diseases. In aged individuals, although transforming growth factor β (TGFβ) is upregulated, its canonical Smad3 signaling is greatly reduced and neuroinflammation persists. This age-related Smad3 impairment reduces protective activation while facilitating cytotoxic activation of microglia through several cellular mechanisms, potentiating microglia-mediated neurodegeneration. Here, we critically discuss the role of TGFβ-Smad signaling on the cytotoxic activation of microglia and its relevance in the pathogenesis of AD. Other protective functions, such as phagocytosis, although observed in aged animals, are not further induced by inflammatory stimuli and TGFβ1. Analysis in silico revealed that increased expression of receptor scavenger receptor (SR)-A, involved in Aβ uptake and cell activation, by microglia exposed to TGFβ, through a Smad3-dependent mechanism could be mediated by transcriptional co-factors Smad2/3 over the MSR1 gene. We discuss that changes of TGFβ-mediated regulation could at least partially mediate age-associated microglia changes, and, together with other changes on inflammatory response, could result in the reduction of protective activation and the potentiation of cytotoxicity of microglia, resulting in the promotion of neurodegenerative diseases.
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Affiliation(s)
- Rommy von Bernhardi
- Laboratory of Neuroscience, Faculty of Medicine, Department of Neurology, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Francisca Cornejo
- Laboratory of Neuroscience, Faculty of Medicine, Department of Neurology, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Guillermo E Parada
- Laboratory of Neuroscience, Faculty of Medicine, Department of Neurology, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Jaime Eugenín
- Laboratory of Neural Systems, Faculty of Chemistry and Biology, Department of Biology, Universidad de Santiago de Chile Santiago, Chile
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12
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Wolf IML, Fan Z, Rauh M, Seufert S, Hore N, Buchfelder M, Savaskan NE, Eyüpoglu IY. Histone deacetylases inhibition by SAHA/Vorinostat normalizes the glioma microenvironment via xCT equilibration. Sci Rep 2014; 4:6226. [PMID: 25228443 PMCID: PMC4165982 DOI: 10.1038/srep06226] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 08/04/2014] [Indexed: 12/13/2022] Open
Abstract
Malignant gliomas are characterized by neurodegenerative actions leading to the destruction of surrounding brain parenchyma. The disturbance in glutamate homeostasis caused by increased expression of the glutamate transporter xCT plays a key role in glioma progression. We demonstrate that the HDAC-inhibitor SAHA specifically inhibits the xCT-transporter expression. Thereby, tumor cell stress is engendered, marked by increase in ROS. Moreover, SAHA dependent xCT-reduction correlates with the inhibition of ATF4-expression, a factor known to foster xCT expression. Since xCT/system Xc- is pivotal for the brain tumor microenvironment, normalization of this system is a key in the management of malignant gliomas. To date, the problem lay in the inability to specifically target xCT due to the ubiquitous expression of the xCT-transporter—i.e. in non-cancerously transformed cells too—as well as its essential role in physiological CNS processes. Here, we show xCT-transporter equilibration through SAHA is specific for malignant brain tumors whereas SAHA does not affect the physiological xCT levels in healthy brain parenchyma. Our data indicate that SAHA operates on gliomas specifically via normalizing xCT expression which in consequence leads to reduced extracellular glutamate levels. This in turn causes a marked reduction in neuronal cell death and normalized tumor microenvironment.
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Affiliation(s)
- Ines M L Wolf
- 1] Department of Neurosurgery, Universitätsklinikum Erlangen, Friedrich Alexander Universität Erlangen-Nürnberg (FAU) [2]
| | - Zheng Fan
- 1] Department of Neurosurgery, Universitätsklinikum Erlangen, Friedrich Alexander Universität Erlangen-Nürnberg (FAU) [2]
| | - Manfred Rauh
- Department of Pediatrics and Adolescent Medicine, University of Erlangen-Nuremberg
| | | | - Nirjhar Hore
- Department of Neurosurgery, Universitätsklinikum Erlangen, Friedrich Alexander Universität Erlangen-Nürnberg (FAU)
| | - Michael Buchfelder
- Department of Neurosurgery, Universitätsklinikum Erlangen, Friedrich Alexander Universität Erlangen-Nürnberg (FAU)
| | - Nic E Savaskan
- 1] Department of Neurosurgery, Universitätsklinikum Erlangen, Friedrich Alexander Universität Erlangen-Nürnberg (FAU) [2]
| | - Ilker Y Eyüpoglu
- 1] Department of Neurosurgery, Universitätsklinikum Erlangen, Friedrich Alexander Universität Erlangen-Nürnberg (FAU) [2]
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13
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Smith C, Gentleman SM, Leclercq PD, Murray LS, Griffin WST, Graham DI, Nicoll JAR. The neuroinflammatory response in humans after traumatic brain injury. Neuropathol Appl Neurobiol 2013; 39:654-66. [PMID: 23231074 PMCID: PMC3833642 DOI: 10.1111/nan.12008] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 12/07/2012] [Indexed: 01/14/2023]
Abstract
AIMS Traumatic brain injury is a significant cause of morbidity and mortality worldwide. An epidemiological association between head injury and long-term cognitive decline has been described for many years and recent clinical studies have highlighted functional impairment within 12 months of a mild head injury. In addition chronic traumatic encephalopathy is a recently described condition in cases of repetitive head injury. There are shared mechanisms between traumatic brain injury and Alzheimer's disease, and it has been hypothesized that neuroinflammation, in the form of microglial activation, may be a mechanism underlying chronic neurodegenerative processes after traumatic brain injury. METHODS This study assessed the microglial reaction after head injury in a range of ages and survival periods, from <24-h survival through to 47-year survival. Immunohistochemistry for reactive microglia (CD68 and CR3/43) was performed on human autopsy brain tissue and assessed 'blind' by quantitative image analysis. Head injury cases were compared with age matched controls, and within the traumatic brain injury group cases with diffuse traumatic axonal injury were compared with cases without diffuse traumatic axonal injury. RESULTS A major finding was a neuroinflammatory response that develops within the first week and persists for several months after traumatic brain injury, but has returned to control levels after several years. In cases with diffuse traumatic axonal injury the microglial reaction is particularly pronounced in the white matter. CONCLUSIONS These results demonstrate that prolonged microglial activation is a feature of traumatic brain injury, but that the neuroinflammatory response returns to control levels after several years.
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Affiliation(s)
- Colin Smith
- Academic Dept. of Neuropathology, University of Edinburgh, Wilkie Building, Teviot Place, Edinburgh, EH8 9AG
- University Academic Dept. of Neuropathology, Institute of Neurological Sciences, Southern General Hospital, Glasgow, G51 4TF, UK
| | - Stephen M Gentleman
- Neuropathology Unit, Department of Medicine, Imperial College London, Charing Cross Campus, St Dunstan’s Road, London, W6 8RP, UK
| | - Pascale D Leclercq
- Neuropathology Unit, Department of Medicine, Imperial College London, Charing Cross Campus, St Dunstan’s Road, London, W6 8RP, UK
| | - Lilian S Murray
- University Academic Dept. of Neuropathology, Institute of Neurological Sciences, Southern General Hospital, Glasgow, G51 4TF, UK
| | - W Sue T Griffin
- Donald W Reynolds Department of Geriatrics, The University of Arkansas for Medical Sciences, and the Geriatric Research Education Clinical Center, Central Arkansas Veterans Healthcare System, Little Rock, AR 72205, USA
| | - David I Graham
- University Academic Dept. of Neuropathology, Institute of Neurological Sciences, Southern General Hospital, Glasgow, G51 4TF, UK
| | - James A R Nicoll
- Clinical Neurosciences, University of Southampton, Southampton General Hospital, Southampton, SO16 6YD
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14
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Kuffler DP. Hyperbaric oxygen therapy: can it prevent irradiation-induced necrosis? Exp Neurol 2012; 235:517-27. [PMID: 22465460 DOI: 10.1016/j.expneurol.2012.03.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 02/27/2012] [Accepted: 03/17/2012] [Indexed: 10/28/2022]
Abstract
Radiosurgery is an important non-invasive procedure for the treatment of tumors and vascular malformations. However, in addition to killing target tissues, cranial irradiation induces damage to adjacent healthy tissues leading to neurological deterioration in both pediatric and adult patients, which is poorly understood and insufficiently treatable. To minimize irradiation damage to healthy tissue, not the optimal therapeutic irradiation dose required to eliminate the target lesion is used but lower doses. Although the success rate of irradiation surgery is about 95%, 5% of patients suffer problems, most commonly neurological, that are thought to be a direct consequence of irradiation-induced inflammation. Although no direct correlation has been demonstrated, the appearance and disappearance of inflammation that develops following irradiation commonly parallel the appearance and disappearance of neurological side effects that are associated with the neurological function of the irradiated brain regions. These observations have led to the hypothesis that brain inflammation is causally related to the observed neurological side effects. Studies indicate that hyperbaric oxygen therapy (HBOT) applied after the appearance of irradiation-induced neurological side effects reduces the incidence and severity of those side effects. This may result from HBOT reducing inflammation, promoting angiogenesis, and influencing other cellular functions thereby suppressing events that cause the neurological side effects. However, it would be significantly better for the patient if rather than waiting for neurological side effects to become manifest they could be avoided. This review examines irradiation-induced neurological side effects, methods that minimize or resolve those side effects, and concludes with a discussion of whether HBOT applied following irradiation, but before manifestation of neurological side effects may prevent or reduce the appearance of irradiation-induced neurological side effects.
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Affiliation(s)
- Damien P Kuffler
- Institute of Neurobiology, University of Puerto Rico, Medical Sciences Campus, Puerto Rico.
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15
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Merz F, Bechmann I. Irradiation of human tumor tissue cultures: optimizing ion radiation therapy. Future Oncol 2011; 7:489-91. [PMID: 21463137 DOI: 10.2217/fon.11.18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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16
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Kraft AD, Kaltenbach LS, Lo DC, Harry GJ. Activated microglia proliferate at neurites of mutant huntingtin-expressing neurons. Neurobiol Aging 2011; 33:621.e17-33. [PMID: 21482444 DOI: 10.1016/j.neurobiolaging.2011.02.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 02/01/2011] [Accepted: 02/16/2011] [Indexed: 01/13/2023]
Abstract
In Huntington's disease (HD), mutated huntingtin (mhtt) causes striatal neurodegeneration which is paralleled by elevated microglia cell numbers. In vitro corticostriatal slice and primary neuronal culture models, in which neuronal expression of mhtt fragments drives HD-like neurotoxicity, were employed to examine wild type microglia during both the initiation and progression of neuronal pathology. As neuronal pathology progressed, microglia initially localized in the vicinity of neurons expressing mhtt fragments increased in number, demonstrated morphological evidence of activation, and expressed the proliferation marker, Ki67. These microglia were positioned along irregular neurites, but did not localize with mhtt inclusions nor exacerbate mhtt fragment-induced neurotoxicity. Prior to neuronal pathology, microglia upregulated ionized calcium binding adaptor molecule 1 (Iba1), signaling a functional shift. With neurodegeneration, interleukin-6 and complement component 1q were increased. The results suggest a stimulatory, proliferative signal for microglia present at the onset of mhtt fragment-induced neurodegeneration. Thus, microglia effect a localized inflammatory response to neuronal mhtt expression that may serve to direct microglial removal of dysfunctional neurites or aberrant synapses, as is required for reparative actions in vivo.
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Affiliation(s)
- Andrew D Kraft
- Neurotoxicology Group, Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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17
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Merz F, Müller M, Taucher-Scholz G, Rödel F, Stöcker H, Schopow K, Laprell L, Dehghani F, Durante M, Bechmann I. Tissue slice cultures from humans or rodents: a new tool to evaluate biological effects of heavy ions. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2010; 49:457-462. [PMID: 20490530 DOI: 10.1007/s00411-010-0293-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 05/02/2010] [Indexed: 05/29/2023]
Abstract
The aim of this interdisciplinary project is to establish slice culture preparations from rodents and humans as a new model system for studying effects of X-rays and heavy ions within normal and tumor tissues. The advantage of such slice cultures relies on the conservation of an organotypic environment, the easy treatment and observation by live-imaging microscopy, and the independence from genetic immortalization strategies used to generate cell lines. Rat brains as well as human tumors were cut into 300-mum-thick sections and cultivated in an incubator in a humidified atmosphere at 37 degrees C. This is realized by a membrane-based culture system with a liquid-air interface. With this system, it is possible to keep rodent slices viable for several months. Human brain tumor slices remained vital for at least 21 days. Slices were irradiated with X-rays at the radiation facility of the University Hospital in Frankfurt/Main at doses up to 40 Gy. Heavy ion irradiations were performed at GSI (Darmstadt) with different ions, energies, and doses. The irradiated slices were analyzed by 3D-confocal microscopy following immunostaining for DNA damage, microglia, and proliferation markers. The phosphorylated histone gammaH2AX proved to be suitable for the detection of ion traversals in this system.
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Affiliation(s)
- Felicitas Merz
- Institute of Anatomy, University of Leipzig, Liebigstr. 13, 04103 Leipzig, Germany
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18
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Ricci I, Artacho R, Olalla M. Milk Protein Peptides With Angiotensin I-Converting Enzyme Inhibitory (ACEI) Activity. Crit Rev Food Sci Nutr 2010; 50:390-402. [DOI: 10.1080/10408390802304198] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Ignacio Ricci
- Department de Nutrition and Bromatology, College of Pharmacy, University of Granada, Spain
| | - Reyes Artacho
- Department de Nutrition and Bromatology, College of Pharmacy, University of Granada, Spain
| | - Manuel Olalla
- Department de Nutrition and Bromatology, College of Pharmacy, University of Granada, Spain
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19
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Hung J, Chansard M, Ousman SS, Nguyen MD, Colicos MA. Activation of microglia by neuronal activity: results from a new in vitro paradigm based on neuronal-silicon interfacing technology. Brain Behav Immun 2010; 24:31-40. [PMID: 19559784 DOI: 10.1016/j.bbi.2009.06.150] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Revised: 06/17/2009] [Accepted: 06/19/2009] [Indexed: 11/29/2022] Open
Abstract
Cognition and behavior primarily arise from the communication that occurs between brain cells. By using photoconductive stimulation to trigger localized regions of neuronal action potentials and astrocyte Ca(2+) waves in dissociated rat hippocampal cultures, we can directly study microglia behavior in response to physiological and pathological levels of activity. Connections between neurons can be modified by microglia, which regulate gap junctions and synapses through secretion of proteins such as cytokines, proteases and neurotrophic factors. Activated microglia participate in bidirectional communication with the excitable tissues that they support. Through feedback from the many ion channels and surface receptors they express, microglia are informed of neuronal and astrocytic activity that may indicate disruption in the homeostasis of the CNS. Such disturbances alert microglia to locations of such activity and promote their transformation into a reactive state, in which they perform adaptive functions that can be either neuroprotective, neurotoxic, or neuromodulatory. Under physiological conditions, normal brain activity has the effect of suppressing microglia inflammatory responses. This report summarizes available data about the interaction of microglia and brain activity and presents a new in vitro paradigm to study the mechanisms involved. We propose that photoconductive stimulation is a powerful tool for studying the cellular and molecular mechanisms underlying the dynamic interactions between neurons, astrocytes and microglia.
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Affiliation(s)
- Johanna Hung
- Department of Physiology & Pharmacology, University of Calgary, Calgary, AB, Canada T2N 4N1
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20
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von Bernhardi R, Tichauer JE, Eugenín J. Aging-dependent changes of microglial cells and their relevance for neurodegenerative disorders. J Neurochem 2009; 112:1099-114. [PMID: 20002526 DOI: 10.1111/j.1471-4159.2009.06537.x] [Citation(s) in RCA: 178] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Among multiple structural and functional brain changes, aging is accompanied by an increase of inflammatory signaling in the nervous system as well as a dysfunction of the immune system elsewhere. Although the long-held view that aging involves neurocognitive impairment is now dismissed, aging is a major risk factor for neurodegenerative diseases such as Alzheimer;s disease, Parkinson;s disease and Huntington's disease, among others. There are many age-related changes affecting the brain, contributing both to certain declining in function and increased frailty, which could singly and collectively affect neuronal viability and vulnerability. Among those changes, both inflammatory responses in aged brains and the altered regulation of toll like receptors, which appears to be relevant for understanding susceptibility to neurodegenerative processes, are linked to pathogenic mechanisms of several diseases. Here, we review how aging and pro-inflammatory environment could modulate microglial phenotype and its reactivity and contribute to the genesis of neurodegenerative processes. Data support our idea that age-related microglial cell changes, by inducing cytotoxicity in contrast to neuroprotection, could contribute to the onset of neurodegenerative changes. This view can have important implications for the development of new therapeutic approaches.
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Affiliation(s)
- Rommy von Bernhardi
- Department of Neurology, Faculty of Medicine, Pontificia Universidad Católica de Chile, Marcoleta, Santiago, Chile.
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21
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Engelhorn T, Savaskan NE, Schwarz MA, Kreutzer J, Meyer EP, Hahnen E, Ganslandt O, Dörfler A, Nimsky C, Buchfelder M, Eyüpoglu IY. Cellular characterization of the peritumoral edema zone in malignant brain tumors. Cancer Sci 2009; 100:1856-62. [PMID: 19681905 PMCID: PMC11159753 DOI: 10.1111/j.1349-7006.2009.01259.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Brain edema is a hallmark of human malignant brain tumors and contributes to the clinical course and outcome of brain tumor patients. The so-called perifocal edema or brain swelling imposes in T2-weighted MR scans as high intensity areas surrounding the bulk tumor mass. The mechanisms of this increased fluid attraction and the cellular composition of the microenvironment are only partially understood. In this study, we focus on imaging perifocal edema in orthotopically implanted gliomas in rodents and correlate perifocal edema with immunohistochemical markers. We identified that areas of perifocal edema not only include the tumor invasion zone, but also are associated with increased glial fibrillary acidic protein (GFAP) and aquaporin-4 expression surrounding the bulk tumor mass. Moreover, a high number of activated microglial cells expressing CD11b and macrophage migration inhibitory factor (MIF) accumulate at the tumor border. Thus, the area of perifocal edema is mainly dominated by reactive changes of vital brain tissue. These data corroborate that perifocal edema identified in T2-weighted MR scans are characterized with alterations in glial cell distribution and marker expression forming an inflammatory tumor microenvironment.
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Affiliation(s)
- Tobias Engelhorn
- Department of Neuroradiology, University of Erlangen-Nuremberg, Erlangen, Germany
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22
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Wong AM, Rozovsky I, Arimoto JM, Du Y, Wei M, Morgan TE, Finch CE. Progesterone influence on neurite outgrowth involves microglia. Endocrinology 2009; 150:324-32. [PMID: 18772232 PMCID: PMC2630906 DOI: 10.1210/en.2008-0988] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Progesterone (P4) antagonizes estradiol (E2) in synaptic remodeling in the hippocampus during the rat estrous cycle. To further understand how P4 modulates synaptic plasticity, we used entorhinal cortex lesions, which induce E2-dependent neurite sprouting in the hippocampus. In young ovariectomized rats, the E2-dependent entorhinal cortex lesion-induced sprouting was attenuated by concurrent treatment with P4 and E2. Microglial activation also showed the E2-P4 antagonism. These findings extend reports on the estrous cycle synaptic remodeling without lesions by showing the P4-E2 antagonism during simultaneous treatment with both E2 and P4. Glial mechanisms were analyzed with the wounding-in-a-dish model of cocultured glia and embryonic d-18 cortical neurons from rat. In cocultures of mixed glia (astrocytes plus 30% microglia), P4 antagonized the E2-dependent neurite outgrowth (number and length) and neuron viability in the presence of E2, as observed in vivo. However, removal of microglia (astrocyte-neuron coculture) abolished the antagonism of E2 by P4 on neuron sprouting. The P4 receptor antagonists ORG-31710 and RU-486 blocked the antagonism of P4 on E2-dependent sprouting. These findings suggest a new role for microglia in P4 antagonism of E2 in neuronal plasticity and show its dependence on progesterone receptors. These findings are also relevant to the inclusion of progestins in hormone therapy, which is controversial in relation to cognitive declines during aging and in Alzheimer's disease.
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Affiliation(s)
- Angela M Wong
- Biogerontology Division, Davis School of Gerontology, University of Southern California, Los Angeles, California 90089, USA
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23
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Falo MC, Reeves TM, Phillips LL. Agrin expression during synaptogenesis induced by traumatic brain injury. J Neurotrauma 2008; 25:769-83. [PMID: 18627255 DOI: 10.1089/neu.2008.0511] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Interaction between extracellular matrix proteins and regulatory proteinases can mediate synaptic integrity. Previously, we documented that matrix metalloproteinase 3 (MMP-3) expression and activity increase following traumatic brain injury (TBI). We now report protein and mRNA analysis of agrin, a MMP-3 substrate, over the time course of trauma-induced synaptogenesis. Agrin expression during the successful synaptic reorganization of unilateral entorhinal cortical lesion (UEC) was compared with expression when normal synaptogenesis fails (combined fluid percussion TBI and bilateral entorhinal lesion [BEC]). We observed that agrin protein was increased in both models at 2 and 7 days postinjury, and immuohistochemical (IHC) co-localization suggested reactive astrocytes contribute to that increase. Agrin formed defined boundaries for sprouting axons along deafferented dendrites in the UEC, but failed to do so after combined insult. Similarly, Western blot analysis revealed greater increase in UEC agrin protein relative to the combined TBI+BEC model. Both models showed increased agrin transcription at 7 days postinjury and mRNA normalization by 15 days. Attenuation of synaptic pathology with the NMDA antagonist MK-801 reduced 7-day UEC agrin transcript to a level not different from unlesioned controls. By contrast, MK-801 in the combined insult failed to significantly change 7-day agrin transcript, mRNA levels remaining elevated over uninjured sham cases. Together, these results suggest that agrin plays an important role in the sprouting phase of reactive synaptogenesis, and that both its expression and distribution are correlated with extent of successful recovery after TBI. Further, when pathogenic conditions which induce synaptic plasticity are reduced, increase in agrin mRNA is attenuated.
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Affiliation(s)
- M Cristina Falo
- Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University Medical Center, Richmond, Virginia 23298, USA
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24
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Abstract
Alzheimer disease (AD) is a major cause of dementia. Several mechanisms have been postulated to explain its pathogenesis, beta-amyloid (A beta toxicity, cholinergic dysfunction, Tau hyper-phosphorylation, oxidative damage, synaptic dysfunction and inflammation secondary to senile plaques, among others. Glial cells are the major producers of inflammatory mediators, and cytotoxic activation of glial cells is linked to several neurodegenerative diseases; however, whether inflammation is a consequence or the cause of neurodegeneration is still unclear. I propose that inflammation and cellular stress associated with aging are key events in the development of AD through the induction of glial dysfunction. Dysregulated inflammatory response can elicit glial cell activation by compounds which are normally poorly reactive. Inflammation can also be the major cause of defective handling of A beta and the amyloid precursor protein (APP). Here I review evidence that support the proposal that dysfunctional glia and the resulting neuroinflammation can explain many features of AD. Evidence supports the notion that damage caused by inflammation is not only a primary cause of neurodegeneration but also an inducer for the accumulation of A beta in AD. Dysfunctional glia can result in impaired neuronal function in AD, as well as in many progressive neurodegenerative disorders. We show that microglial cell activation is enhanced under pro-inflammatory conditions, indicating that glial cell responses to A beta related proteins can be critically dependent on the priming of glial cells by pro-inflammatory factors.
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25
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Deller T, Del Turco D, Rappert A, Bechmann I. Structural reorganization of the dentate gyrus following entorhinal denervation: species differences between rat and mouse. PROGRESS IN BRAIN RESEARCH 2008; 163:501-28. [PMID: 17765735 DOI: 10.1016/s0079-6123(07)63027-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Deafferentation of the dentate gyrus by unilateral entorhinal cortex lesion or unilateral perforant pathway transection is a classical model to study the response of the central nervous system (CNS) to denervation. This model has been extensively characterized in the rat to clarify mechanisms underlying denervation-induced gliosis, transneuronal degeneration of denervated neurons, and collateral sprouting of surviving axons. As a result, candidate molecules have been identified which could regulate these changes, but a causal link between these molecules and the postlesional changes has not yet been demonstrated. To this end, mutant mice are currently studied by many groups. A tacit assumption is that data from the rat can be generalized to the mouse, and fundamental species differences in hippocampal architecture and the fiber systems involved in sprouting are often ignored. In this review, we will (1) provide an overview of some of the basics and technical aspects of the entorhinal denervation model, (2) identify anatomical species differences between rats and mice and will point out their relevance for the axonal reorganization process, (3) describe glial and local inflammatory changes, (4) consider transneuronal changes of denervated dentate neurons and the potential role of reactive glia in this context, and (5) summarize the differences in the reorganization of the dentate gyrus between the two species. Finally, we will discuss the use of the entorhinal denervation model in mutant mice.
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Affiliation(s)
- Thomas Deller
- Institute of Clinical Neuroanatomy, J.W. Goethe-University, Theodor-Stern-Kai 7, D-60590 Frankfurt/Main, Germany.
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26
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Abstract
Chemokine CXCL1 is abundantly present in proliferative zones during brain development and in regions of remyelination, suggesting that it influences development of oligodendrocyte progenitors (OPC) in these regions. We studied in vitro the effects and possible mechanisms by which CXCL1 acts on human fetal OPC. In organotypic slice cultures of human fetal cortical ventricular/subventricular (VZ/SVZ) zones, blocking of CXCL1 signaling reduced significantly the proliferation of OPC. Moreover, exogenously added CXCL1 induced increase of OPC proliferation. Treatments of purified OPC cultures and cell depletion experiments demonstrated that this effect of CXCL1 was mainly indirect, mediated through astrocytes. We identified that CXCL1 acted through the extracellular signal regulated kinase (ERK1/2) pathway, activated primarily in astrocytes. In vitro, astrocytes stimulated with CXCL1 released several cytokines, but only the release of interleukin-6 (IL-6) was completely blocked by inhibition of ERK1/2 pathway. When released IL-6 was neutralized in slices, a decrease in OPC proliferation was demonstrated, while addition of IL-6 was able to return OPC proliferation in astrocyte-depleted slices to the control level. These results suggest that in the human fetal brain CXCL1 promotes proliferation of early OPC, acting in part through an ERK1/2-dependent pathway and release of IL-6 from astrocytes.
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Affiliation(s)
- Radmila Filipovic
- Department of Neuroscience, University of Connecticut Health Center, Farmington, Connecticut 06030-3401, USA.
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27
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Hayes M, Stanton C, Fitzgerald GF, Ross RP. Putting microbes to work: Dairy fermentation, cell factories and bioactive peptides. Part II: Bioactive peptide functions. Biotechnol J 2007; 2:435-49. [PMID: 17407211 DOI: 10.1002/biot.200700045] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A variety of milk-derived biologically active peptides have been shown to exert both functional and physiological roles in vitro and in vivo, and because of this are of particular interest for food science and nutrition applications. Biological activities associated with such peptides include immunomodulatory, antibacterial, anti-hypertensive and opioid-like properties. Milk proteins are recognized as a primary source of bioactive peptides, which can be encrypted within the amino acid sequence of dairy proteins, requiring proteolysis for release and activation. Fermentation of milk proteins using the proteolytic systems of lactic acid bacteria is an attractive approach for generation of functional foods enriched in bioactive peptides given the low cost and positive nutritional image associated with fermented milk drinks and yoghurt. In Part II of this review, we focus on examples of milk-derived bioactive peptides and their associated health benefits, to illustrate the potential of this area for the design and improvement of future functional foods.
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Affiliation(s)
- Maria Hayes
- Teagasc, Moorepark Food Research Centre, Fermoy, Co. Cork, Ireland
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28
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Almeida-Leite CMD, Galvão LMDC, Afonso LCC, Cunha FDQ, Arantes RME. Interferon-γ induced nitric oxide mediates in vitro neuronal damage by Trypanosoma cruzi-infected macrophages. Neurobiol Dis 2007; 25:170-8. [PMID: 17056264 DOI: 10.1016/j.nbd.2006.09.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Revised: 09/01/2006] [Accepted: 09/05/2006] [Indexed: 11/21/2022] Open
Abstract
Neuronal lesions and peripheral denervation in Chagas' disease are related to local inflammation; however, the pathogenic mechanisms of neuronal lesions in the heart and megavisceras are still unclear. We investigated the involvement of nitric oxide (NO) on neuronal lesion in co-cultures of neurons and macrophages. Trypanosoma cruzi-infected and interferon-gamma (IFN-gamma)-activated co-cultures of neurons and wild-type (WT) macrophages showed significant reduction of both neuronal survival and neurite density. These findings correlated with the levels of NO and the expression of inducible nitric oxide synthase (iNOS). Accordingly, neuronal survival rate in the co-cultures was recovered to control levels by treatment of the cultures with the iNOS inhibitor, aminoguanidine. Moreover, neither neuronal survival nor the neurite density was affected in the co-cultures when the macrophages were harvested from iNOS-deficient mice. These results demonstrate that iNOS-derived NO is the major molecule involved in neuronal damage mechanism in our in vitro model of Chagas' disease neuropathology.
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Affiliation(s)
- Camila Megale de Almeida-Leite
- Department of Pathology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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29
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de Yebra L, Malpesa Y, Ursu G, Pugliese M, Liévens JC, Kerkerian-Le Goff L, Mahy N. Dissociation between hippocampal neuronal loss, astroglial and microglial reactivity after pharmacologically induced reverse glutamate transport. Neurochem Int 2006; 49:691-7. [PMID: 16965840 DOI: 10.1016/j.neuint.2006.06.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2006] [Revised: 05/23/2006] [Accepted: 06/12/2006] [Indexed: 11/20/2022]
Abstract
The inflammatory central nervous system response that involves activated microglia and reactive astrocytes may both heal and harm neurons, as inflammatory mediators lead to neuroprotection or excitation at one dose but to injury at a different concentration. To investigate these complex cellular interactions, L-trans-pyrrolidine-2,4-dicarboxylate (PDC), a selective substrate inhibitor of glutamate transport, was infused during 14 days in the rat hippocampus at three different rates: 5, 10 and 25 nmol/h. A microglial reaction appeared at the 5 nmol/h PDC rate in absence of astroglial reaction and neuronal loss. Microgliosis and neuronal death were observed at PDC 10 nmol/h in absence of astrogliosis and calcium precipitation, whereas all four aspects were present at the highest rate. This dissociation between neuronal loss and astroglial reactivity took place in presence of a permanent microglial reaction. These data suggest a specific response of microglia to PDC whose neuronal effects may differ with the infused dose.
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Affiliation(s)
- Lluïsa de Yebra
- Unitat de Bioquímica, IDIBAPS, Facultat de Medicina, Universitat de Barcelona, C/ Casanova 143, Barcelona E-08036, Spain
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Mutlu L, Brandt C, Kwidzinski E, Sawitzki B, Gimsa U, Mahlo J, Aktas O, Nitsch R, van Zwam M, Laman JD, Bechmann I. Tolerogenic effect of fiber tract injury: reduced EAE severity following entorhinal cortex lesion. Exp Brain Res 2006; 178:542-53. [PMID: 17091291 DOI: 10.1007/s00221-006-0758-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Accepted: 10/10/2006] [Indexed: 12/25/2022]
Abstract
Despite transient, myelin-directed adaptive immune responses in regions of fiber tract degeneration, none of the current models of fiber tract injuries evokes disseminated demyelination, implying effective mechanisms maintaining or re-establishing immune tolerance. In fact, we have recently detected CD95L upregulation accompanied by apoptosis of leukocytes in zones of axonal degeneration induced by entorhinal cortex lesion (ECL), a model of layer-specific axonal degeneration. Moreover, infiltrating monocytes readily transformed into ramified microglia exhibiting a phenotype of immature (CD86+/CD80-) antigen-presenting cells. We now report the appearance of the axonal antigen neurofilament-light along with increased T cell apoptosis and enhanced expression of the pro-apoptotic gene Bad in cervical lymph nodes after ECL. In order to test the functional significance of such local and systemic depletory/regulatory mechanisms on subsequent immunity to central nervous system antigens, experimental autoimmune encephalomyelitis was induced by proteolipid protein immunization 30 days after ECL. In three independent experiments, we found significantly diminished disease scores and infiltrates in lesioned compared to sham-operated SJL mice. This is consistent with a previous meta-statistical analysis (Goodin et al. in Neurology 52:1737-1745, 1999) rejecting the O-hypothesis that brain trauma causes or exacerbates multiple sclerosis. Conversely, brain injuries may involve long-term tolerogenic effects towards brain antigens.
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Affiliation(s)
- Leman Mutlu
- Institute of Cell Biology and Neurobiology, Charité, 10098, Berlin, Germany
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Falo MC, Fillmore HL, Reeves TM, Phillips LL. Matrix metalloproteinase-3 expression profile differentiates adaptive and maladaptive synaptic plasticity induced by traumatic brain injury. J Neurosci Res 2006; 84:768-81. [PMID: 16862547 DOI: 10.1002/jnr.20986] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The interaction between extracellular matrix (ECM) and regulatory matrix metalloproteinases (MMPs) is important in establishing and maintaining synaptic connectivity. By using fluid percussion traumatic brain injury (TBI) and combined TBI and bilateral entorhinal cortical lesion (TBI + BEC), we previously demonstrated that hippocampal stromelysin-1 (MMP-3) expression and activity increased during synaptic plasticity. We now report a temporal analysis of MMP-3 protein and mRNA response to TBI during both degenerative (2 day) and regenerative (7, 15 day) phases of reactive synaptogenesis. MMP-3 expression during successful synaptic reorganization (following unilateral entorhinal cortical lesion; UEC) was compared with MMP-3 expression when normal synaptogenesis fails (after combined TBI + BEC insult). Increased expression of MMP-3 protein and message was observed in both models at 2 days postinjury, and immuohistochemical (IHC) colocalization suggested that reactive astrocytes contribute to that increase. By 7 days postinjury, model differences in MMP-3 were observed. UEC MMP-3 mRNA was equivalent to control, and MMP-3 protein was reduced within the deafferented region. In contrast, enzyme mRNA remained elevated in the maladaptive TBI + BEC model, accompanied by persistent cellular labeling of MMP-3 protein. At 15 days survival, MMP-3 mRNA was normalized in each model, but enzyme protein remained higher than paired controls. When TBI + BEC recovery was enhanced by the N-methyl-D-aspartate antagonist MK-801, 7-day MMP-3 mRNA was significantly reduced. Similarly, MMP inhibition with FN-439 reduced the persistent spatial learning deficits associated with TBI + BEC insult. These results suggest that MMP-3 might differentially affect the sequential phases of reactive synaptogenesis and exhibit an altered pattern when recovery is perturbed.
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Affiliation(s)
- M C Falo
- Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University Medical Center, Richmond, 23298, USA
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32
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Momčilović B, Lykken GI, Cooley M. Natural distribution of environmental radon daughters in the different brain areas of an Alzheimer disease victim. Mol Neurodegener 2006; 1:11. [PMID: 16965619 PMCID: PMC1579210 DOI: 10.1186/1750-1326-1-11] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2006] [Accepted: 09/11/2006] [Indexed: 11/26/2022] Open
Abstract
Background Radon is a ubiquitous noble gas in the environment and a primary source of harmful radiation exposure for humans; it decays in a cascade of daughters (RAD) by releasing the cell damaging high energy alpha particles. Results We studied natural distribution of RAD 210Po and 210Bi in the different parts of the postmortem brain of 86-year-old woman who had suffered from Alzheimer's disease (AD). A distinct brain map emerged, since RAD distribution was different among the analyzed brain areas. The highest RAD irradiation (mSv·year-1) occurred in the decreasing order of magnitude: amygdale (Amy) >> hippocampus (Hip) > temporal lobe (Tem) ~ frontal lobe (Fro) > occipital lobe (Occ) ~ parietal lobe (Par) > substantia nigra (SN) >> locus ceruleus (LC) ~ nucleus basalis (NB); generally more RAD accumulated in the proteins than lipids of gray and white (gray > white) brain matter. Amy and Hip are particularly vulnerable brain structure targets to significant RAD internal radiation damage in AD (5.98 and 1.82 mSv·year-1, respectively). Next, naturally occurring RAD radiation for Tem and Fro, then Occ and Par, and SN was an order of magnitude higher than that in LC and NB; the later was within RAD we observed previously in the healthy control brains. Conclusion Naturally occurring environmental RAD exposure may dramatically enhance AD deterioration by selectively targeting brain areas of emotions (Amy) and memory (Hip).
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Affiliation(s)
- Berislav Momčilović
- Institute for Medical Research and Occupational Health, PO Box 291, 10001 Zagreb, Croatia
| | - Glenn I Lykken
- Department of Physics, University of North Dakota, Grand Forks, ND 58202-7129, USA
| | - Marvin Cooley
- Department of Pathology, University of North Dakota, Grand Forks, ND 58202-7129, USA
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Hölsken A, Eyüpoglu IY, Lueders M, Tränkle C, Dieckmann D, Buslei R, Hahnen E, Blümcke I, Siebzehnrübl FA. Ex vivo therapy of malignant melanomas transplanted into organotypic brain slice cultures using inhibitors of histone deacetylases. Acta Neuropathol 2006; 112:205-15. [PMID: 16773328 DOI: 10.1007/s00401-006-0082-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2005] [Revised: 04/28/2006] [Accepted: 04/28/2006] [Indexed: 12/17/2022]
Abstract
Disease progression in patients suffering from malignant melanomas is often determined by metastatic spreading into brain parenchyma. Systemic chemotherapy regimens are, therefore, mandatory for successful treatment. Most recently, inhibitors of histone deacetylases (HDACi) have been shown to significantly inhibit melanoma progression. Here, mouse as well as human melanoma cells were transplanted into rodent hippocampal slice cultures in order to translate and microscopically confirm promising in vitro chemotherapeutic propensities of HDACi within the organotypic brain environment. In our ex vivo model, tumor progression was significantly inhibited by administration of low micromolar concentrations of second generation HDACi MS-275 over a period of 8 days. In contrast, HDACi treatment with suberoylanilide hydroxamic acid was less efficient ex vivo, although both compounds were successful in the treatment of tumor cell monolayer cultures. Protein levels of the cell cycle inhibitor p21(WAF1) were significantly increased after HDACi treatment, which points to enhanced G1 arrest of tumor cells as confirmed by cytofluorometric analysis. Considering the ability of MS-275 to cross the blood-brain barrier, our experimental model identifies the benzamide MS-275 as a promising therapeutic compound for targeting epigenetic chromatin modulation as systemic treatment of metastatic melanomas.
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Affiliation(s)
- Annett Hölsken
- Department of Neuropathology, University of Erlangen-Nuremberg, Krankenhausstr. 8-10, 91054, Erlangen, Germany
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Eyüpoglu IY, Hahnen E, Tränkle C, Savaskan NE, Siebzehnrübl FA, Buslei R, Lemke D, Wick W, Fahlbusch R, Blümcke I. Experimental therapy of malignant gliomas using the inhibitor of histone deacetylase MS-275. Mol Cancer Ther 2006; 5:1248-55. [PMID: 16731757 DOI: 10.1158/1535-7163.mct-05-0533] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Inhibitors of histone deacetylases are promising compounds for the treatment of cancer but have not been systematically explored in malignant brain tumors. Here, we characterize the benzamide MS-275, a class I histone deacetylase inhibitor, as potent drug for experimental therapy of glioblastomas. Treatment of four glioma cell lines (U87MG, C6, F98, and SMA-560) with MS-275 significantly reduced cell growth in a concentration-dependent manner (IC(90), 3.75 micromol/L). Its antiproliferative effect was corroborated using a bromodeoxyuridine proliferation assay and was mediated by G(0)-G(1) cell cycle arrest (i.e., up-regulation of p21/WAF) and apoptotic cell death. Implantation of enhanced green fluorescent protein-transfected F98 glioma cells into slice cultures of rat brain confirmed the cytostatic effect of MS-275 without neurotoxic damage to the organotypic neuronal environment in a dose escalation up to 20 micromol/L. A single intratumoral injection of MS-275 7 days after orthotopic implantation of glioma cells in syngeneic rats confirmed the chemotherapeutic efficacy of MS-275 in vivo. Furthermore, its propensity to pass the blood-brain barrier and to increase the protein level of acetylated histone H3 in brain tissue identifies MS-275 as a promising candidate drug in the treatment of malignant gliomas.
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Affiliation(s)
- Ilker Y Eyüpoglu
- Department of Neurosurgery, University of Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany.
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35
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Vallès A, Grijpink-Ongering L, de Bree FM, Tuinstra T, Ronken E. Differential regulation of the CXCR2 chemokine network in rat brain trauma: Implications for neuroimmune interactions and neuronal survival. Neurobiol Dis 2006; 22:312-22. [PMID: 16472549 DOI: 10.1016/j.nbd.2005.11.015] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2005] [Revised: 11/09/2005] [Accepted: 11/24/2005] [Indexed: 01/03/2023] Open
Abstract
Chemokine receptors represent promising targets to attenuate inflammatory responses and subsequent secondary damage after brain injury. We studied the response of the chemokines CXCL1/CINC-1 and CXCL2/MIP-2 and their receptors CXCR1 and CXCR2 after controlled cortical impact injury in adult rats. Rapid upregulation of CXCL1/CINC-1 and CXCL2/MIP-2, followed by CXCR2 (but not CXCR1), was observed after injury. Constitutive neuronal CXCR2 immunoreactivity was detected in several brain areas, which rapidly but transiently downregulated upon trauma. A second CXCR2-positive compartment, mainly colocalized with the activated microglia/macrophage marker ED1, was detected rapidly after injury in the ipsilateral cortex, progressively emerging into deeper areas of the brain later in time. It is proposed that CXCR2 has a dual role after brain injury: (i) homologous neuronal CXCR2 downregulation would render neurons more vulnerable to injury, whereas (ii) chemotaxis and subsequent differentiation of blood-borne cells into a microglial-like phenotype would be promoted by the same receptor.
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Affiliation(s)
- Astrid Vallès
- Solvay Pharmaceuticals Research Laboratories, C. J. van Houtenlaan 36, 1381 CP Weesp, The Netherlands
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36
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Abstract
How localized synaptic input regulates dendritic branch structure is not well understood. For these experiments, we used single-cell electroporation, live cell imaging, in vitro deafferentation, pharmacology, and electrophysiological stimulation to study how local alterations in synaptic input affect dendritic branch structure in nucleus laminaris (NL). We found that interrupting or modulating synaptic input to distinct sets of NL dendrites can regulate their structure on a very short timescale. Specifically, eliminating synaptic input by deafferenting only one set of the bitufted NL dendrites caused a selective reduction in the total dendritic branch length of the deafferented dendrites but relatively few changes in the normally innervated dendrites on the same cell. An analysis of individual dendritic branch changes demonstrated that both control and deafferented NL dendrites exhibit branch extension and retraction. However, the presence of intact synaptic inputs balanced these changes, maintaining the total dendritic branch length of control dendrites. When glutamate receptor signaling was blocked (DNQX and AP-5), NL neurons exhibited significant dendrite retraction, demonstrating that NL dendrite maintenance depends in part on presynaptic glutamatergic input. Electrophysiological experiments further confirmed that modulating the level of synaptic input regulates NL dendrite structure. Differential stimulation of the two sets of dendrites resulted in a selective reduction in the total dendritic branch length of the unstimulated dendrites and a selective increase in the total dendritic branch length of the stimulated dorsal dendrites. These results suggest that balanced activation of the two sets of NL dendrites is required to maintain the relative amount of dendritic surface area allotted to each input.
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Zhao J, Brooks DM, Lurie DI. Lipopolysaccharide-activated SHP-1-deficient motheaten microglia release increased nitric oxide, TNF-alpha, and IL-1beta. Glia 2006; 53:304-12. [PMID: 16265671 DOI: 10.1002/glia.20283] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Accumulating evidence suggests a deleterious role for activated microglia in facilitating neuronal death by producing neurocytotoxic substances during injury, infection, or neurodegenerative diseases. After cochlear ablation, abnormal microglial activation accompanied by increased neuronal loss within the auditory brainstem occurs in motheaten (me/me) mice deficient in the protein tyrosine phosphatase SHP-1. To determine whether abnormally activated microglia contribute to neuronal death in me/me mice, primary microglial cultures from me/me and wild-type mouse cortices were stimulated by the bacterial endotoxin lipopolysaccharide (LPS) to evaluate the secretion of the neurotoxic mediators nitric oxide (NO), tumor necrosis factor-alpha (TNF-alpha), and interleukin-1beta (IL-1beta). Me/me microglia release significantly greater amounts of all three mediators compared with wild-type microglia. However, the increased release of these compounds in microglia lacking SHP-1 does not appear to occur through activation of extracellular signal-regulated kinase (ERK), p38 kinase subgroups of mitogen-activated protein (MAP) kinases, or increases in NF-kappaB-inducing kinase (NIK). These results suggest that abnormal microglial activation and release of neurotoxic compounds may potentiate neuronal death in deafferented cells and can thus potentiate neurodegeneration in the me/me brainstem. Our data also indicate that SHP-1 is engaged in signaling pathways in LPS-activated microglia, but not through regulation of the ERK and p38 MAP kinases.
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Affiliation(s)
- Jie Zhao
- Department of Biomedical and Pharmaceutical Sciences, School of Pharmacy and Allied Health Sciences, University of Montana, Missoula, MT 59812, USA
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38
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Lünemann A, Ullrich O, Diestel A, Jöns T, Ninnemann O, Kovac A, Pohl EE, Hass R, Nitsch R, Hendrix S. Macrophage/microglia activation factor expression is restricted to lesion-associated microglial cells after brain trauma. Glia 2006; 53:412-9. [PMID: 16342171 DOI: 10.1002/glia.20301] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
After traumatic brain lesion, microglial cells are rapidly activated, migrate toward the sites of injury, and cause secondary damage that accounts for most of the loss of brain function. In the present study, we have characterized a new macrophage/microglia activation factor (MAF). Using the monocytic cell line U937, we were able to demonstrate that MAF is upregulated after TPA-induced differentiation into macrophages. We have generated a specific antibody against MAF. In BV-2 microglial cells, MAF is partially co-localized with IB4, a classical microglial marker. In addition, we have analyzed the in vivo expression patterns of MAF after entorhinal cortex lesion. We were able to show a substantial upregulation of MAF on selected CD11b(+) and IB4(+) macrophages/microglial cells in the deafferented hippocampus and in the perilesional region, while no MAF expression was detectable on the contralateral side. Confocal microscopy revealed a lysosome-like expression pattern in BV-2 cells, as well as in ECL-associated macrophages/microglial cells in vivo. Furthermore, we were able to demonstrate that U937 cells with downregulated MAF converted slower and to a significantly reduced extent to the macrophageal phenotype after TPA treatment. In addition, MAF downregulation in BV-2 microglial cells substantially reduced the phagocytotic uptake of dextran beads. Our data indicate that MAF is expressed in selected macrophages/microglial cells around the lesion and in the degenerating hippocampus after ECL. Furthermore, MAF expression in monocytic cells seems to play a functional role in the differentiation to a phagocytosing phenotype and may be, at least partially, required for phagocytotic activity, specifically in lesioned tissue after brain trauma.
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Affiliation(s)
- Anna Lünemann
- Center for Anatomy, Institute of Cell Biology and Neurobiology, Center for Anatomy, Charité Universitätsmedizin Berlin, Humboldt University, 10098 Berlin, Germany
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Eyüpoglu IY, Hahnen E, Buslei R, Siebzehnrübl FA, Savaskan NE, Lüders M, Tränkle C, Wick W, Weller M, Fahlbusch R, Blümcke I. Suberoylanilide hydroxamic acid (SAHA) has potent anti-glioma properties in vitro, ex vivo and in vivo. J Neurochem 2005; 93:992-9. [PMID: 15857402 DOI: 10.1111/j.1471-4159.2005.03098.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Current treatment modalities for malignant gliomas do not allow long-term survival. Here, we identify suberoylanilide hydroxamic acid (SAHA), an inhibitor of histone deacetylases (HDAC), as an effective experimental anti-glioma agent. Administration of SAHA to various glioma cell lines obtained from human, rat and mouse inhibited tumour cell growth in a range of 1-10 microm. This anti-glioma property is associated with up-regulation of the cell cycle control protein p21/WAF, as well as the induction of apoptosis. A novel tumour invasion model using slice cultures of rat brain corroborated the anti-glioma properties of SAHA in the organotypic brain environment. In this model, glioma invasion compromised adjacent brain parenchyma, and this tumour-associated cytotoxicity could be inhibited by SAHA. In addition, a 10-fold dose escalation experiment did not challenge the viability of cultured brain slices. In vivo, a single intratumoural injection of SAHA 7 days after orthotopic implantation of glioma cells in syngeneic rats doubled their survival time. These observations identify chromatin-modifying enzymes as possible and promising targets for the pharmacotherapy of malignant gliomas.
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Herrera-Molina R, von Bernhardi R. Transforming growth factor-β1 produced by hippocampal cells modulates microglial reactivity in culture. Neurobiol Dis 2005; 19:229-36. [PMID: 15837578 DOI: 10.1016/j.nbd.2005.01.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2004] [Revised: 11/23/2004] [Accepted: 01/04/2005] [Indexed: 11/30/2022] Open
Abstract
Activated microglia produce superoxide anion (O2-) and nitric oxide (NO), both of which can be neurotoxic. To identify regulatory mechanisms that might modulate over-activation of microglia, we evaluated the inhibition of microglial activation by factors secreted by hippocampal cells. Supernatants from hippocampal cell cultures (Hippocampal-Cm) prevented microglial O2- and NO production. LAP-TGF beta1 was present in the Hippocampal-Cm as shown by immunoblot and a TGF beta1-dependent proliferation-inhibition bioassay. LAP-TGF beta1 and TGFbeta activity increased in hippocampal cultures exposed to proinflammatory conditions (LPS and Interferon-gamma). The inhibition of O2- and NO production by Hippocampal-Cm was mimicked by the addition of recombinant TGF beta1. Treating Hippocampal-Cm with an antibody against TGF beta1 to neutralize its activity eliminated its ability to inhibit O2- and NO production. Our findings suggest that the TGF beta1 secreted by hippocampal cells modulated microglial activity. We propose that in pathological conditions, impairment of this modulatory mechanism could enhance microglia-mediated neurotoxicity.
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Affiliation(s)
- Rodrigo Herrera-Molina
- Department of Neurology, Faculty of Medicine, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
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41
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Eyüpoglu IY, Hahnen E, Heckel A, Siebzehnrübl FA, Buslei R, Fahlbusch R, Blümcke I. Malignant glioma-induced neuronal cell death in an organotypic glioma invasion model. Technical note. J Neurosurg 2005; 102:738-44. [PMID: 15871520 DOI: 10.3171/jns.2005.102.4.0738] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Rapid growth and diffuse brain infiltration are hallmarks of malignant gliomas. The underlying molecular pathomechanisms of these tumors, however, remain to be determined. The authors present a novel glioma invasion model that allows researchers to monitor consecutively tumor cell proliferation and migration in an organotypic brain environment. Enhanced green fluorescent protein-labeled F98 rat glioma cells were implanted into slice cultures obtained from a rat hippocampus, and tumor growth was microscopically documented up to 20 days in vitro. Invasion along radially oriented migratory streams could be observed 5 days after implantation of rat F98, human U87MG, and mouse GL261 glioma cells, whereas human Be(2)c neuroblastoma cells and mouse HT22 hippocampal neurons failed to invade the brain parenchyma. Following implantation of F98 glioma cells into the entorhinal cortex, cell death was observed within the infiltrated brain parenchyma as well as in the neuroanatomically connected dentate gyrus. Application of the N-methyl-D-aspartate receptor antagonist MK801 to the culture medium significantly reduced neuronal degeneration in the dentate gyrus, whereas the alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor antagonist GYKI 52466 inhibited peritumoral cytotoxicity. This new model allows researchers to address in a systematic manner the molecular pathways of brain invasion as well as specific tumor-host interactions such as necrosis.
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Affiliation(s)
- Ilker Y Eyüpoglu
- Department of Neurosurgery, University of Erlangen-Nuremberg Department of Neuropathology, University of Erlangen-Nuremberg, Erlangen, Germany.
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Rappert A, Bechmann I, Pivneva T, Mahlo J, Biber K, Nolte C, Kovac AD, Gerard C, Boddeke HWGM, Nitsch R, Kettenmann H. CXCR3-dependent microglial recruitment is essential for dendrite loss after brain lesion. J Neurosci 2005; 24:8500-9. [PMID: 15456824 PMCID: PMC6729901 DOI: 10.1523/jneurosci.2451-04.2004] [Citation(s) in RCA: 194] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Microglia are the resident macrophage population of the CNS and are considered its major immunocompetent elements. They are activated by any type of brain pathology and can migrate to the lesion site. The chemokine CXCL10 is expressed in neurons in response to brain injury and is a signaling candidate for activating microglia and directing them to the lesion site. We recently identified CXCR3, the corresponding receptor for CXCL10, in microglia and demonstrated that this receptor system controls microglial migration. We have now tested the impact of CXCR3 signaling on cellular responses after entorhinal cortex lesion. In wild-type mice, microglia migrate within the first 3 d after lesion into the zone of axonal degeneration, where 8 d after lesion denervated dendrites of interneurons are subsequently lost. In contrast, the recruitment of microglia was impaired in CXCR3 knock-out mice, and, strikingly, denervated distal dendrites were maintained in zones of axonal degeneration. No differences between wild-type and knock-out mice were observed after facial nerve axotomy, as a lesion model for assessing microglial proliferation. This shows that CXCR3 signaling is crucial in microglia recruitment but not proliferation, and this recruitment is an essential element for neuronal reorganization.
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Affiliation(s)
- Angelika Rappert
- Department of Cellular Neuroscience, Max Delbrück Center for Molecular Medicine, 13092 Berlin, Germany
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Seiffert E, Dreier JP, Ivens S, Bechmann I, Tomkins O, Heinemann U, Friedman A. Lasting blood-brain barrier disruption induces epileptic focus in the rat somatosensory cortex. J Neurosci 2005; 24:7829-36. [PMID: 15356194 PMCID: PMC6729929 DOI: 10.1523/jneurosci.1751-04.2004] [Citation(s) in RCA: 359] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Perturbations in the integrity of the blood-brain barrier have been reported in both humans and animals under numerous pathological conditions. Although the blood-brain barrier prevents the penetration of many blood constituents into the brain extracellular space, the effect of such perturbations on the brain function and their roles in the pathogenesis of cortical diseases are unknown. In this study we established a model for focal disruption of the blood-brain barrier in the rat cortex by direct application of bile salts. Exposure of the cerebral cortex in vivo to bile salts resulted in long-lasting extravasation of serum albumin to the brain extracellular space and was associated with a prominent activation of astrocytes with no inflammatory response or marked cell loss. Using electrophysiological recordings in brain slices we found that a focus of epileptiform discharges developed within 4-7 d after treatment and could be recorded up to 49 d postoperatively in >60% of slices from treated animals but only rarely (10%) in sham-operated controls. Epileptiform activity involved both glutamatergic and GABAergic neurotransmission. Epileptiform activity was also induced by direct cortical application of native serum, denatured serum, or albumin-containing solution. In contrast, perfusion with serum-adapted electrolyte solution did not induce abnormal activity, thereby suggesting that the exposure of the serum-devoid brain environment to serum proteins underlies epileptogenesis in the blood-brain barrier-disrupted cortex. Although many neuropathologies entail a compromised blood-brain barrier, this is the first direct evidence that it may have a role in the pathogenesis of focal cortical epilepsy, a common neurological disease.
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Affiliation(s)
- Ernst Seiffert
- Johannes-Müller-Institute of Physiology, Charité, University Medicine, 10117 Berlin, Germany
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Nichols NR, Agolley D, Zieba M, Bye N. Glucocorticoid regulation of glial responses during hippocampal neurodegeneration and regeneration. ACTA ACUST UNITED AC 2005; 48:287-301. [PMID: 15850668 DOI: 10.1016/j.brainresrev.2004.12.019] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2004] [Accepted: 12/09/2004] [Indexed: 10/25/2022]
Abstract
Glucocorticoids can prevent or accelerate neurodegeneration in the adult rat hippocampus. To investigate these actions of glucocorticoids, we previously cloned genes from the hippocampus. Adrenalectomy specifically increased glial fibrillary acidic protein and transforming growth factor (TGF)-beta1 mRNAs in the dentate gyrus and these effects were dependent on induced apoptosis. Corticosterone treatment prevented apoptosis, and decreased glial activation and the influx of activated microglia. Since these effects are opposite to injury and neurodegeneration, we propose that they represent adaptive actions of glucocorticoids, preventing cellular defense mechanisms from overshooting. We used adrenalectomy as a model to investigate how adult granule neurons die in vivo and the effects of neurotrophic factors in protecting against apoptosis. Neurotrophin-4/5 and TGF-beta1 protected granule neurons against adrenalectomy-induced apoptosis. Since neurogenesis is also greatly increased in the dentate gyrus following adrenalectomy, we compared the time course of birth and death with glial responses. TGF-beta1 mRNA increased before the detection of dying cells in the dentate gyrus, which was coincident with increased proliferation in the neurogenic zone. Glucocorticoids also increased Ndrg2 mRNA in glia in the neurogenic zone; Ndrg2 is a member of a novel gene family involved in neural differentiation and synapse formation. Therefore, studying the effects of glucocorticoid manipulation on the dentate gyrus is increasing our understanding of how mature neurons die by apoptosis and the role of glia in induced apoptosis and neurogenesis. Discovering how endocrine and inflammatory responses regulate neuron birth and survival is important for developing successful neuron replacement strategies to treat neurodegenerative diseases.
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Affiliation(s)
- Nancy R Nichols
- Department of Physiology, Building 13F, Monash University, Clayton, Australia.
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Bechmann I, Goldmann J, Kovac AD, Kwidzinski E, Simbürger E, Naftolin F, Dirnagl U, Nitsch R, Priller J. Circulating monocytic cells infiltrate layers of anterograde axonal degeneration where they transform into microglia. FASEB J 2005; 19:647-9. [PMID: 15671154 DOI: 10.1096/fj.04-2599fje] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In this study, we demonstrate the infiltration of blood-derived monocytic cells and their morphologic transformation into microglia in zones of acute, anterograde (Wallerian) axonal degeneration induced by entorhinal cortex lesion (ECL). ECL was performed in mice which had received green fluorescent protein (GFP)-transduced bone marrow grafts allowing identification of blood-derived elements within the brain. While in the unlesioned hemisphere GFP+ cells were restricted to perivascular and leptomeningeal sites, many round fluorescent cells appeared in hippocampal zones of axonal degeneration at 24 h post lesion (hpl). Within 72 hpl, these GFP+ cells acquired ramified, microglia-like morphologies, which persisted for at least 7 days post ECL. Differentiation of GFP+ cells into glial fibrillary acidic protein (GFAP)+ astrocytes was never observed. To exclude that this recruitment is an artifact of irradiation or bone marrow transplantation, the fluorescent cell tracker 6-carboxylfluorescein diacetate (CFDA) was injected into spleens of normal mice 1 day before ECL. Again, fluorescent cells appeared at the lesion site and along the layers of axonal degeneration at 48 hpl and CFDA+/MAC-1+, cells exhibited amoeboid and ramified morphologies. Thus, blood-derived cells infiltrate not only the site of mechanical lesion, but also the layers of anterograde axonal degeneration, where they readily transform into microglia-like elements. A role for infiltrating leukocytes in facilitating or modulating postlesional plasticity, e.g., by phagocytosis of growth-inhibiting myelin should now be considered. Moreover, monocytic cells may serve as vehicles to transport therapeutic substances such as neurotrophic factors or caspase inhibitors to zones of axonal degeneration.
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Affiliation(s)
- Ingo Bechmann
- Institute of Cell Biology and Neurobiology, Charité University Hospital, Berlin, Germany.
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Schweizer U, Bräuer AU, Köhrle J, Nitsch R, Savaskan NE. Selenium and brain function: a poorly recognized liaison. ACTA ACUST UNITED AC 2004; 45:164-78. [PMID: 15210302 DOI: 10.1016/j.brainresrev.2004.03.004] [Citation(s) in RCA: 244] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/09/2004] [Indexed: 01/08/2023]
Abstract
Molecular biology has recently contributed significantly to the recognition of selenium (Se)2 and Se-dependent enzymes as modulators of brain function. Increased oxidative stress has been proposed as a pathomechanism in neurodegenerative diseases including, among others, Parkinson's disease, stroke, and epilepsy. Glutathione peroxidases (GPx), thioredoxin reductases, and one methionine-sulfoxide-reductase are selenium-dependent enzymes involved in antioxidant defense and intracellular redox regulation and modulation. Selenium depletion in animals is associated with decreased activities of Se-dependent enzymes and leads to enhanced cell loss in models of neurodegenerative disease. Genetic inactivation of cellular GPx increases the sensitivity towards neurotoxins and brain ischemia. Conversely, increased GPx activity as a result of increased Se supply or overexpression ameliorates the outcome in the same models of disease. Genetic inactivation of selenoprotein P leads to a marked reduction of brain Se content, which has not been achieved by dietary Se depletion, and to a movement disorder and spontaneous seizures. Here we review the role of Se for the brain under physiological as well as pathophysiological conditions and highlight recent findings which open new vistas on an old essential trace element.
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Affiliation(s)
- Ulrich Schweizer
- Neurobiology of Selenium, Neuroscience Research Center, Charité, University Medical School, Berlin, Germany
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Shoham S, Youdim MBH. Nutritional iron deprivation attenuates kainate-induced neurotoxicity in rats: implications for involvement of iron in neurodegeneration. Ann N Y Acad Sci 2004; 1012:94-114. [PMID: 15105258 DOI: 10.1196/annals.1306.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
There is evidence suggesting that oxidative stress contributes to kainate neurotoxicity. Since iron promotes oxidative stress, the present study explores how change in nutritional iron content modulates kainate-induced neurotoxicity. Rats received an iron-deficient diet (ID) from 22 days of age for 4 weeks. One control group received the same diet supplemented with iron and another control group received standard rodent diet. Cellular damage after subcutaneous kainate (10 mg/kg) was assessed by silver impregnation and gliosis by staining microglia. ID reduced cellular damage in piriform and entorhinal cortex, in thalamus, and in hippocampal layers CA1-3. ID also attenuated gliosis, except in the hippocampal CA1 layer. Given involvement of zinc in hippocampal neurotransmission and in oxidative stress, we tested for a possible interaction of nutritional iron with nutritional zinc. Rats were made iron-deficient and then assigned to supplementation with iron, zinc, or iron + zinc. Controls were continued on ID diet. After 2 weeks, rats were treated with kainate. Iron supplementation abolished the protective effect of ID in piriform and entorhinal cortex. In hippocampal CA1 and dorsal thalamus, neither iron nor zinc supplementation alone abolished the protective effect of ID against cellular damage. Iron + zinc supplementation abolished ID protection in dorsal thalamus, but not in reuniens nucleus. Kainate-induced gliosis in CA1 remained unaffected by nutritional treatments. Thus, in piriform and entorhinal cortex, nutritional iron has a major impact on cellular damage and gliosis. In hippocampal CA1, gliosis may associate with synaptic plasticity not modulated by nutritional iron, while cellular damage is sensitive to nutritional iron and zinc.
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Affiliation(s)
- S Shoham
- Research Department, Herzog Hospital, Jerusalem, Israel.
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Bräuer AU, Nitsch R, Savaskan NE. Identification of macrophage/microglia activation factor (MAF) associated with late endosomes/lysosomes in microglial cells. FEBS Lett 2004; 563:41-8. [PMID: 15063720 DOI: 10.1016/s0014-5793(04)00244-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2004] [Revised: 02/20/2004] [Accepted: 02/25/2004] [Indexed: 11/22/2022]
Abstract
Damage to the central nervous system triggers rapid activation and specific migration of glial cells towards the lesion site. There, glial cells contribute heavily to secondary neuronal changes that take place after lesion. In an attempt to identify the molecular cues of glial activation following brain trauma we performed differential display reverse transcription-polymerase chain reaction screenings from lesioned and control hippocampus. Here we report on the identification of the macrophage/microglia activation factor (MAF), a new membrane protein with seven putative transmembrane domains. Expression analysis revealed that MAF is predominantly expressed in microglial cells in the brain, and is upregulated following brain lesion. Overexpression of MAF in non-glial cells shows an intracellular codistribution with the lysosomal marker endosome/lysosome-associated membrane protein-1 (lamp-1). Furthermore, MAF-transfected cells show that MAF is primarily associated with late endosomes/lysosomes, and that this association can be disrupted by activation of protein kinase C-dependent pathways. In conclusion, these results imply that MAF is involved in the dynamics of lysosomal membranes associated with microglial activation following brain lesion.
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Affiliation(s)
- Anja U Bräuer
- Institute of Cell Biology and Neurobiology, Center for Anatomy, Charité University Medical School Berlin, Philippstr. 12, D-10115 Berlin, Germany
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