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Neural Stem Cell Transplantation Induces Stroke Recovery by Upregulating Glutamate Transporter GLT-1 in Astrocytes.

UNLABELLED: Ischemic stroke is the leading cause of disability, but effective therapies are currently widely lacking. Recovery from stroke i … emic and ischemic area, to promote the upregulation of the glial glutamate transporter 1 (GLT-1) on astrocytes and to reduce peri-ischemic extracellular glutamate. The upregulation of GLT-1 induced by transplanted NPCs was found to rely on the secretion of VEGF by NPCs. Blocking VEGF during the first week after stroke reduced GLT-1 upregulation as well as lo …

Neurofilament-labeled pyramidal neurons and astrocytes are deficient in DNA methylation marks in Alzheimer's disease.

There is increasing evidence that epigenetic alterations may play a role in Alzheimer's disease (AD); yet, there is little information regar … logy are deficient in extranuclear 5mC in AD cases compared with controls. We also found that fewer astrocytes exhibited nuclear 5mC and 5hmC marks in AD cases compared with controls. However, there were no alterations in 5mC and 5hmC in disease-resistant calretinin interneurons or microglia in AD, and there was no alteration in the density of 5mC- or 5hmC-l …

Investigation on cellular interactions of astrocytes with zinc oxide nanoparticles using rat C6 cell lines.

Zinc oxide nanoparticles (ZnO NPs) are widely used in cosmetic industries and have also found important applications in electrical and chemical industries. It is well documented that inhaled ZnO NPs can reach the brain through the olfactory neuronal pathway and can interfere with the brain zinc homeostasis. Most of the studies focus on the toxicity of ZnO NPs on neuronal cells and microglia. Not much work is available on the bio interaction of ZnO NPs with astrocytes, the major cells involved in brain homeostasis. Therefore, this study focuses on the interaction of ZnO NPs with rat C6 glial ce…

Metallothionein-3 modulates the amyloid β endocytosis of astrocytes through its effects on actin polymerization.

BACKGROUND: Astrocytes may play important roles in the pathogenesis of Alzheimer's disease (AD) by clearing extracellular amyloid beta (Aβ) through endocytosis and degradation. We recently showed that metallothionein 3 (Mt3), a zinc-binding metallothionein that is enriched in the central nervous system, contributes to actin polymerization in astrocytes. Because actin is likely involved in the endocytosis of Aβ, we investigated the possible role of Mt3 in Aβ endocytosis by cortical astrocytes in this study. RESULTS: To assess the route of Aβ uptake, we exposed cultured astrocytes to fluorescen…

Enhanced Ca(2+)-dependent glutamate release from astrocytes of the BACHD Huntington's disease mouse model.

Huntington's disease (HD) causes preferential loss of a subset of neurons in the brain although the huntingtin protein is expressed broadly in various neural cell types, including astrocytes. Glutamate-mediated excitotoxicity is thought to cause selective neuronal injury, and brain astrocytes have a central role in regulating extracellular glutamate. To determine whether full-length mutant huntingtin expression causes a cell-autonomous phenotype and perturbs astrocyte gliotransmitter release, we studied cultured cortical astrocytes from BACHD mice. Here, we report augmented glutamate release t…

Chronic exposure of astrocytes to interferon-α reveals molecular changes related to Aicardi-Goutieres syndrome.

Aicardi-Goutières syndrome is a genetically determined infantile encephalopathy, manifesting as progressive microcephaly, psychomotor retardation, and in ∼25% of patients, death in early childhood. Aicardi-Goutières syndrome is caused by mutations in any of the genes encoding TREX1, RNASEH2-A, -B, -C and SAMHD1, with protein dysfunction hypothesized to result in the accumulation of nucleic acids within the cell, thus triggering an autoinflammatory response with increased interferon-α production. Astrocytes have been identified as a major source of interferon-α production in the brains of patie…

Astrocytes generated from patient induced pluripotent stem cells recapitulate features of Huntington's disease patient cells.

BACKGROUND: Huntington's Disease (HD) is a devastating neurodegenerative disorder that clinically manifests as motor dysfunction, cognitive impairment and psychiatric symptoms. There is currently no cure for this progressive and fatal disorder. The causative mutation of this hereditary disease is a trinucleotide repeat expansion (CAG) in the Huntingtin gene that results in an expanded polyglutamine tract. Multiple mechanisms have been proposed to explain the preferential striatal and cortical degeneration that occurs with HD, including non-cell-autonomous contribution from astrocytes. Although…

Manganese inhibits ATP-induced calcium entry through the transient receptor potential channel TRPC3 in astrocytes.

Chronic exposure to elevated levels of manganese (Mn(2+)) causes neuronal injury and inflammatory activation of glia. Astrocytes selectively accumulate Mn(2+), which inhibits mitochondrial respiration and increases production of reactive oxygen species. We previously reported that sub-acute exposure to low micromolar levels of Mn(2+) in primary astrocytes inhibited ATP-induced calcium (Ca(2+)) signaling, associated with decreased levels of endoplasmic reticulum Ca(2+) and increased mitochondrial Ca(2+) loads. In the present studies, we postulated that the mechanism underlying the capacity of M…

CMX001 (1-O-hexadecyloxypropyl-cidofovir) inhibits polyomavirus JC replication in human brain progenitor-derived astrocytes.

Polyomavirus JC (JCV) replication causes progressive multifocal leukoencephalopathy (PML), a frequently fatal brain disease in immunodeficient patients, yet antiviral drugs are lacking. We characterized the lipid conjugate 1-O-hexadecyloxypropyl-cidofovir (CMX001) regarding JCV (Mad-4) replication in human brain progenitor-derived astrocytes (PDA) and the simian virus 40 (SV40) large-T-antigen-expressing COS-7 cells up to 7 days postinfection (dpi). We examined JCV loads by PCR, the infection rate by immunofluorescence, and host cell toxicity by WST-1 and BrdU incorporation assays. Supernatant…

Type-dependent oxidative damage in frontotemporal lobar degeneration: cortical astrocytes are targets of oxidative damage.

Oxidative injury and stress responses are common features of many neurodegenerative diseases. To assess oxidative stress responses in fronto … tion in all positive cases; confocal microscopy revealed colocalization of HNE and GFAP in cortical astrocytes, superoxide dismutase 1 in astrocytes, and superoxide dismutase 2 in astrocytes and neurons in all FTLD types. Thus, in FTLD, there is variable disease-dependent oxidative damage that is prominent in FTLD-tau, astrocytes are targets of oxidative dam …

Astrocytes induce hemeoxygenase-1 expression in microglia: a feasible mechanism for preventing excessive brain inflammation.

Microglia are the major inflammatory cells in the brain, in which microglial inflammatory responses are modulated by interactions with other brain cells. Here, we show that astrocytes, the most abundant cells in the brain, can secrete one or more factors capable of modulating microglial activation by regulating the microglial levels of reactive oxygen species (ROS). Treatment of microglia with astrocyte culture-conditioned media (ACM) increased the expression level and activity of hemeoxygenase-1 (HO-1). ACM also induced nuclear translocation of the nuclear factor E2-related factor 2 transcrip…

Glutathione modulation influences methyl mercury induced neurotoxicity in primary cell cultures of neurons and astrocytes.

Methyl mercury (MeHg) is highly neurotoxic and may lead to numerous neurodegenerative disorders. In this study, we investigated the role of glutathione (GSH) and reactive oxygen species (ROS) in MeHg-induced neurotoxicity, using primary cell cultures of cerebellar neurons and astrocytes. To evaluate the effect of GSH on MeHg-induced cytotoxicity, ROS and GSH were measured using the fluorescent indicators chloro methyl derivative of di-chloro di-hydro fluorescein diacetate (CMH(2)DCFDA) and monochlorobimane (MCB). Cell-associated MeHg was measured with (14)C-radiolabeled MeHg. Mitochondrial deh…

Induction of classical and nonclassical MHC-I on mouse brain astrocytes by Japanese encephalitis virus.

Infection with Flaviviruses upregulates the cell surface expression of MHC-I, MHC-II, ICAM-1 (CD54), VCAM-1 (CD106) and TAP proteins. Although all these studies have been confirmed using West Nile virus and other Flaviviruses, there are few reports that have examined the effects of Japanese encephalitis virus (JEV) infection directly on nonclassical and classical MHC expression in astrocytes. We show in this report that JEV infection of mouse brain astrocytes results in induction of the nonclassical MHC Class Ib genes, H-2T23, H-2Q4 and H-2T10 in addition to MHC-I, Type I (alpha/beta) IFNs, TA…

Vimentin-expressing proximal reactive astrocytes correlate with migration rather than proliferation following focal brain injury.

Vimentin-expressing astrocytes in the adult are commonly associated with the proximal, most reactive gliotic response ultimately leading to the formation of a new glial limitans. It was thought, since vimentin expression and astroglial proliferation are most prominent nearest the lesion site, that vimentin may be a characteristic of immature newly divided astrocytes. We recently established a unique distribution of vimentin-expressing reactive astrocytes at the base of a focal cortical ischemic lesion in rats. The purpose of the present study was to assess the correlation of proliferation and …

Улучшенное выражение 14-3-3 белков в реактивных астроцитах в мозгах болезни Креуцфельдт-Якоб.

Согласно сообщениям, 14-3-3 белки обнаруживаются непосредственно в цереброспиновой жидкости (CSF) у пациентов с болезнью Креуцфельдта-Якоба (CJD). Чтобы прояснить роль 14-3-3 белков у пациентов с CJD, мы провели иммунохимические исследования 14-3-3 белков в вскрываемом мозге у пяти пациентов с спорадическим CJD (SCJD), трех пациентов с болезнью Альцгеймера (AD) и семи обычных субъектов контроля. Формально закреплённые парафиновые отсеки из всех случаев были иммунизированы несколькими типами специальных антител против 14-3-3. В обычных мозгах управления иммуноактивность 14-3-3 была локализована

Совпадение в аннотации оригинала
14-3-3 proteins have been reported to be detected specifically in the cerebrospinal fluid (CSF) from patients with Creutzfeldt-Jakob disease … was well preserved in the remaining neurons. Furthermore, the glial cells, especially the reactive astrocytes, were intensely immunostained in the brains affected by sCJD. Our findings suggest that 14-3-3 proteins may be up-regulated in the glial cells, particularly in reactive astrocytes, and that the enhanced expression of 14-3-3 proteins in these glial e …

Chlorotoxin-sensitive Ca2+-activated Cl- channel in type R2 reactive astrocytes from adult rat brain.

Astrocytes express four types of Cl(-) or anion channels, but Ca(2+)-activated Cl(-) (Cl(Ca)) channels have not been described. We studied Cl(-) channels in a morphologically distinct subpopulation ( approximately 5% of cells) of small (10-12 micro m, 11.8 +/- 0.6 pF), phase-dark, GFAP-positive native reactive astrocytes (NRAs) freshly isolated from injured adult rat brains. Their resting potential, -57.1 +/- 4.0 mV, polarized to -72.7 +/- 4.5 mV with BAPTA-AM, an intracellular Ca(2+) chelator, and depolarized to -30.7 +/- 6.1 mV with thapsigargin, which mobilizes Ca(2+) from intracellular sto…

Mercuric chloride, but not methylmercury, inhibits glutamine synthetase activity in primary cultures of cortical astrocytes.

Methylmercury (MeHg) is highly neurotoxic with an apparent dose-related latency period between time of exposure and the appearance of symptoms. Astrocytes are known targets for MeHg toxicity and a site of mercury localization within the central nervous system (CNS). Glutamine synthetase (GS) is an enzyme localized predominately within astrocytes. GS converts two potentially toxic molecules, glutamate and ammonia, to the relatively non-toxic amino acid, glutamine. During prolonged exposure to MeHg, inorganic mercury (I-Hg) accumulates within the brain, suggesting in situ demethylation of MeHg t…

Astrocytes in sensory circumventricular organs of the rat brain express functional binding sites for endothelin.

Sensory circumventricular organs bordering the anterior third cerebral ventricle, the subfornical organ and the organum vasculosum laminae terminalis, lack blood-brain barrier characteristics and are therefore accessible to circulating peptides like endothelins. Astrocytes of the rat subfornical organ and organum vasculosum laminae terminalis additionally showed immunocytochemical localization of endothelin-1/endothelin-3-like peptides, possibly acting as circumventricular organ-intrinsic modulators. Employing [125I]endothelin-1 as radioligand, quantitative autoradiography demonstrated specifi…

In vitro induction of nitric oxide synthase in astrocytes and microglia by Trypanosoma brucei brucei.

In stage II human african trypanosomiasis (HAT), which is characterized by central nervous system (CNS) involvement, neurones and oligodendrocytes might be targets of dysimmune processes. Nitric oxide (NO) production by peripheral macrophages is documented in HAT. We studied the production of NO by murine astrocytes and microglia cocultured with Trypanosoma brucei (T. b.) brucei AnTat 1.9. Purified astrocytes or microglia from mouse brains were cocultured with T. b. brucei, and in some instances with interferon (IFN)-gamma, which is known to be released during the disease and also to be a grow…

Influence of calcium and iron on cell death and mitochondrial function in oxidatively stressed astrocytes.

Astrocytes protect neurons and oligodendrocytes by buffering ions, neurotransmitters, and providing metabolic support. However, astrocytes are also vulnerable to oxidative stress, which may affect their protective and supportive functions. This paper examines the influence of calcium and iron on astrocytes and determines if cell death could be mediated by mitochondrial dysfunction. We provide evidence that the events associated with peroxide-induced death of astrocytes involves generation of superoxide at the site of mitochondria, loss of mitochondrial membrane potential, and depletion of ATP.…