TY - JOUR. T1 - Acidosis-induced metallothionein (MT) mRNA expression in neonatal rat primary astrocyte cultures. AU - Aschner, M.. AU - Stark, S.. AU - Vrana, K. E.. AU - Conklin, D. R.. PY - 1998/4/15. Y1 - 1998/4/15. N2 - Metallothionein (MT) mRNA levels were determined following exposure of neonatal rat primary astrocyte cultures to acidosis. Astrocyte total RNA was probed on northern blots with [α32P]dCTP-labeled synthetic cDNA probes specific for rat MT isoform mRNAs. The probe for MT-I mRNA hybridized to a single mRNA with a size appropriate for MT, approximately 550 nucleotides. MT-I mRNA levels in astrocyte monolayers exposed to pH 6.5 and 6.0 for 3 or 6 hours were unchanged compared with MT-I mRNA levels in control cultures exposed to pH 7.4. In contrast, 9 hour exposure of astrocytes to pH 6.5 and 6.0 led to a significant increase in MT-I mRNA transcripts compared with controls maintained at pH 7.4 (p,0.001 and p,0.02, respectively). A probe for MT-II mRNA that hybridizes to a single ...
TY - JOUR. T1 - Infection of primary human fetal astrocytes by human herpesvirus 6. AU - Jun, H. E.. AU - McCarthy, Micheline. AU - Zhou, Y. I.. AU - Chandran, Bala. AU - Wood, Charles. PY - 1996/1/29. Y1 - 1996/1/29. N2 - Human herpesvirus 6 (HHV-6) is a lymphotropic betaherpesvirus which productively infects human CD4+ T cells and monocytes. HHV-6 is the etiologic agent for exanthem subitum (roseola), and it is well-known that central nervous system complications occur frequently during the course of HHV-6-associated disease. In addition, HHV-6 has been associated with encephalitis or encephalopathy. However, very little is known about its tropism for neural cells. There are reports that HHV-6 may infect some glial cell lines, but whether it can infect any primary neural cells is not known. Our studies show that both HHV-6A (GS) and HHV-6B (Z-29) can infect highly purified primary fetal astrocytes in vitro. Infected cells showed cytopathic effects, forming giant syncytia. In dual ...
TY - JOUR. T1 - Protein phosphorylation in primary astrocyte cultures treated with and without dibutyryl cyclic AMP. AU - Neary, Joseph T.. AU - Gutierrez, Maria del Pilar. AU - Norenberg, Luz Oliva B.. AU - Norenberg, Michael D.. PY - 1987/4/28. Y1 - 1987/4/28. N2 - Protein phosphorylation was investigated in primary rat astrocyte cultures treated with and without dibutyryl cyclic AMP. Astrocytes maintained in dibutyryl cyclic AMP for several weeks displayed increased phosphate incorporation in 5 protein bands (55, 52, 45, 43 and 28 kDa) while incorporation in one band (42 kDa) was decreased. Phosphate incorporation in several other protein bands was unchanged. Calcium-dependent phosphate incorporation was also altered by prior exposure of the cells to dibutyryl cyclic AMP: addition of calcium to broken cell preparations resulted in increased incorporation in 75, 53 and 52 kDa while decreased incorporation occurred in 100 kDa. These differences in protein phosphorylation may be related to the ...
We report here a novel live imaging approach to study astrocyte response to ischemic injury in the brains of living mice. Our results revealed marked effects of sex and estrogen on astrocyte response to ischemic injury. We report here that: (1) bioluminescent signal intensities/GFAP induction were significantly higher in female mice (out of estrus) compared with males (confirmed by immunohistochemistry); (2) in female mice, astrocyte response to ischemia/GFAP upregulation was strongly dependent on the estrus cycle and serum estrogen level; and (3) contrary to the findings in male mice, there was no correlation between bioluminescent signal intensity/GFAP upregulation and size of the ischemic lesion in female GFAP-luc mice.. GFAP is a 50-kDa intermediate filament, predominantly expressed by mature astrocytes in the central nervous system.24,25 Reactive astrogliosis is a key component of the inflammatory cellular response to central nervous system injury, including ischemia.2,26 It is ...
article{9714ffdf-1e21-475d-ac0b-daebdc2182ca, abstract = {Clearance of the amyloid-P peptide (A beta) as a remedy for Alzheimers disease (AD) is a major target in on-going clinical trials. In vitro studies confirmed that A beta is taken up by rodent astrocytes, but knowledge on human astrocyte-mediated A beta clearance is sparse. Therefore, by means of flow cytometry and confocal laser scanning microscopy (CLSM), we evaluated the binding and internalization of A beta 1-42 by primary human fetal astrocytes and adult astrocytes, isolated from nondemented subjects (n = 8) and AD subjects (n = 6). Furthermore, we analyzed whether alpha 1-antichymotrypsin (ACT), which is found in amyloid plaques and can influence A beta fibrillogenesis, affects the A beta uptake by human astrocytes. Upon over night exposure of astrocytes to FAM-labeled A beta 1-42 (10 mu M) preparations, (80.7 +/- 17.7)% fetal and (52.9 +/- 20.9)% adult A beta-positive astrocytes (P = 0.018) were observed. No significant difference ...
TY - JOUR. T1 - Astrocytes process synaptic information. AU - Araque, Alfonso. PY - 2008/2. Y1 - 2008/2. N2 - Astrocytes were classically considered as simple supportive cells for neurons without a significant role in information processing by the nervous system. However, considerable amounts of evidence obtained by several groups during the past years demonstrated the existence of a bidirectional communication between astrocytes and neurons, which prompted a re-examination of the role of astrocytes in the physiology of the nervous system. While neurons base their excitability on electrical signals generated across the membrane, astrocytes base their cellular excitability on variations of the Ca2+ concentration in the cytosol. This article discusses our current knowledge of the properties of the synaptically evoked astrocyte Ca2+ signal, which reveals that astrocytes display integrative properties for synaptic information processing. Astrocytes respond selectively to different axon pathways, ...
Transfection Efficiency:. Reagent exhibits at least 77% transfection efficiency of siRNA delivery. Transfection efficiency was determined by qRT-PCR.. Transfection Protocol and MSDS:. Download Altogen Biosystems DI-TNC1 Transfection Protocol: [PDF]. Download MSDS: [PDF]. DI-TNC1 Cell Line:. Astrocytes are the most abundant type of cells in the central nervous system that perform a variety of different functions, including support of brain metabolism, the primary focus of which is on the relationship between astrocytes and neurons. Astrocytes are cells that promote the growth of neurons by providing nourishment and support. DI-TNC1 is derived from cultures of interbrain tissue of one-day-old rats and comprises rat brain astrocytes. Cultured astrocytes have been shown to promote neurite outgrowth by producing adhesion molecules found either on the cell surface or in the extracellular matrix. The cells retain characteristics of type 1 astrocytes including glial fibrillary acidic protein (GFAP) ...
Astrocytes are the major glial subtype in the brain and mediate numerous functions ranging from metabolic support to gliotransmitter release through signaling mechanisms controlled by Ca2+. Despite intense interest, the Ca2+ influx pathways in astrocytes remain obscure, hindering mechanistic insights into how Ca2+ signaling is coupled to downstream astrocyte-mediated effector functions. Here, we identified store-operated Ca2+ release-activated Ca2+ (CRAC) channels encoded by Orai1 and STIM1 as a major route of Ca2+ entry for driving sustained and oscillatory Ca2+ signals in astrocytes after stimulation of metabotropic purinergic and protease-activated receptors. Using synaptopHluorin as an optical reporter, we showed that the opening of astrocyte CRAC channels stimulated vesicular exocytosis to mediate the release of gliotransmitters, including ATP. Furthermore, slice electrophysiological recordings showed that activation of astrocytes by protease-activated receptors stimulated interneurons in ...
Our previous findings reveal that A2A and D2 receptors are co-expressed on adult rat striatal astrocytes and on the astrocyte processes, and that A2A-D2 receptorCreceptor conversation can control the release of glutamate from your processes. (and that these heteromers can play functions in the control of the striatal glutamatergic transmission) may shed light on the molecular mechanisms involved in the pathogenesis of the disease. = 3). (B) Aliquots (300 g) of Triton X-100-soluble proteins obtained from gliosomes were immunoprecipitated with 1 g of anti-D2 antibody as explained in Methods. IP and Output were analyzed by immunoblotting using the anti-D2 antibody. IP and Output were also analyzed using anti-A2A antibody. A representative blot (of three) is usually shown. A2A immunoreactive bands were quantified and the data were reported in the graph. Values are means SEM (= 3). 2.2. D2 and A2A Receptors Expressed on Striatal Astrocytes Can Form Heteromers As illustrated in Physique 2 astrocytes ...
Astrocytes derived from Y757F mutant mice defective in gp130-SHP2/SOCS3 signaling were investigated into their ability to respond to IL-6. Compared with WT astrocytes, Y757F astrocytes treated with hyper-IL6, had higher and more sustained activation of STAT3, while the levels of pY-SHP2 and pERK remained unchanged. Gene expression was investigated by Affymetrix gene chip analysis. At 2 hr, 306 genes were upregulated in WT astrocytes and of these, 28 did not increase in Y757F astrocytes. Of 238 genes upregulated in Y757F astrocytes, 9 were not upregulated in WT astrocytes. Some 99 genes were downregulated in WT astrocytes and of those 55 were not decreased in Y757F astrocytes. In WT astrocytes after 12 hrs the level of expression of many genes was reduced back to or near levels seen in the untreated cells, however, in Y757F astrocytes 109 genes either maintained their 2hr upregulated levels or were further increased. A number of candidate genes upregulated by hyper-IL6 in WT and Y757F astrocytes ...
Reactive astrocytes are associated with every form of neurological injury. Despite their ubiquity, the molecular mechanisms controlling their production and diverse functions remain poorly defined. Because many features of astrocyte development are recapitulated in reactive astrocytes, we investigated the role of nuclear factor I-A (NFIA), a key transcriptional regulator of astrocyte development whose contributions to reactive astrocytes remain undefined. Here, we show that NFIA is highly expressed in reactive astrocytes in human neurological injury and identify unique roles across distinct injury states and regions of the CNS. In the spinal cord, after white matter injury (WMI), NFIA-deficient astrocytes exhibit defects in blood-brain barrier remodeling, which are correlated with the suppression of timely remyelination. In the cortex, after ischemic stroke, NFIA is required for the production of reactive astrocytes from the subventricular zone (SVZ). Mechanistically, NFIA directly regulates the ...
Astrocyte activation is presumed to depress neuronal regeneration after CNS injury due to the glial scar, a formation of a physical barrier, and overproduction of multiple proinflammatory cytokines, including IL-1β, IL-6, and TNFα, which further aggravate the glial activation and injure the remaining neurons through positive feedback [4, 31, 38, 39]. The recombinant IL-1β used in the present study was shown to be biologically active as previously demonstrated by its ability to induce astrocyte activation in an in vitro astrocyte activation model [4, 40-42]. Therefore, we speculate that our IL-1β stimulation model is suitable and credible for the detection of the astrocyte activation in vitro. Upregulation of GFAP and hypertrophy of astrocyte cellular processes play a major and prominent role in astrocyte activation and the formation of glial scar [6, 12]. In the present study, the IL-1β stimulation triggered an elevated level of GFAP and induced the astrocyte hypertrophy; this phenomenon ...
The generation of human induced pluripotent stem cells (hiPSCs) represents an exciting advancement with promise for stem cell transplantation therapies as well as for neurological disease modeling. Based on the emerging roles for astrocytes in neurological disorders, we investigated whether hiPSC-derived astrocyte progenitors could be engrafted to the rodent spinal cord and how the characteristics of these cells changed between in vitro culture and after transplantation to the in vivo spinal cord environment. Our results show that human embryonic stem cell- and hiPSC-derived astrocyte progenitors survive long-term after spinal cord engraftment and differentiate to astrocytes in vivo with few cells from other lineages present. Gene profiling of the transplanted cells demonstrates the astrocyte progenitors continue to mature in vivo and upregulate a variety of astrocyte-specific genes. Given this mature astrocyte gene profile, this work highlights hiPSCs as a tool to investigate disease-related ...
TY - JOUR. T1 - Molecular diversity of astrocytes with implications for neurological disorders. AU - Bachoo, Robert M.. AU - Kim, Ryung S.. AU - Ligon, Keith L.. AU - Maher, Elizabeth A.. AU - Brennan, Cameron. AU - Billings, Nathan. AU - Chan, Suzanne. AU - Li, Cheng. AU - Rowitch, David H.. AU - Wong, Wing H.. AU - DePinho, Ronald A.. PY - 2004/6/1. Y1 - 2004/6/1. N2 - The astrocyte represents the most abundant yet least understood cell type of the CNS. Here, we use a stringent experimental strategy to molecularly define the astrocyte lineage by integrating microarray datasets across several in vitro model systems of astrocyte differentiation, primary astrocyte cultures, and various astrocyte-rich CNS structures. The intersection of astrocyte data sets, coupled with the application of nonastrocytic exclusion filters, yielded many astrocyte-specific genes possessing strikingly varied patterns of regional CNS expression. Annotation of these astrocyte-specific genes provides direct molecular ...
Author(s): Shim, Myoung Sup; Kim, Keun-Young; Bu, Jung Hyun; Nam, Hye Seung; Jeong, Seung Won; Park, Tae Lim; Ellisman, Mark H; Weinreb, Robert N; Ju, Won-Kyu | Abstract: Glaucoma is characterized by a progressive loss of retinal ganglion cells and their axons, but the underlying biological basis for the accompanying neurodegeneration is not known. Accumulating evidence indicates that structural and functional abnormalities of astrocytes within the optic nerve head (ONH) have a role. However, whether the activation of cyclic adenosine 3,5-monophosphate (cAMP) signaling pathway is associated with astrocyte dysfunction in the ONH remains unknown. We report here that the cAMP/protein kinase A (PKA) pathway is critical to ONH astrocyte dysfunction, leading to caspase-3 activation and cell death via the AKT/Bim/Bax signaling pathway. Furthermore, elevated intracellular cAMP exacerbates vulnerability to oxidative stress in ONH astrocytes, and this may contribute to axonal damage in glaucomatous
Introduction Astrocytes are the most abundant glial cell type. in C57BL/6 mice TNFSF11 astroglial cells in response to lipopolysaccharide (LPS) using reverse-transcription polymerase BMS-911543 BMS-911543 chain reaction (RT-PCR) method. Results We provide for the first time evidence that astrocytes can express IL-19 mRNA following LPS stimulation. Furthermore we have found the expression of IL-19 mRNA in the cortex of adult C57BL/6 mice following intraperitoneal (i.p.) administration of LPS. Discussion This finding will contribute to current knowledge on the function and behavior of cells and mediators during inflammatory conditions in BMS-911543 the brain. Keywords: IL-19 Mice Astroglial Cells brain Cortex Lipopolysaccharide 1 Introduction Glial cells play an important role in controlling of CNS inflammation. Astrocytes are the most abundant glial cell type in the brain (Kim Hong & BMS-911543 Ro 2011 BMS-911543 Astrocytes are multifunctional glial cells that regulate extracellular ion and ...
In the present study, we aim to elucidate the role of caveolin-1 in modulating astroglial differentiation of neural progenitor cells (NPCs) and the potential mechanisms involved. We first investigated astroglial differentiation and Notch signaling by detecting the expressions of S100β, GFAP, NICD and hairy enhancer of split 1 (Hes1) in the brains of wild-type and caveolin-1 knockout mice. Caveolin-1 knockout mice revealed remarkably less astroglial differentiation and lower levels of NICD and Hes1 expressions than wild type mice. We then studied the potential roles of caveolin-1 in modulating NICD and Hes1 expressions and astroglial differentiation in isolated cultured NPCs by using caveolin-1 peptide and caveolin-1 RNA silencing. In the differentiating NPCs, caveolin-1 peptide markedly promoted astroglial formation and up-regulated the expressions of NICD and Hes1. In contrast, the knockdown of caveolin-1 inhibited astroglial differentiation of NPCs and the expressions of NICD and Hes1. Taken ...
Antigen presentation reactions are dependent upon the expression of the class II major histocompatibility antigens (MHC), the T-cell receptor, and the presented antigen. Recent studies demonstrate that such processes also require the presence of adhesion molecules such as lymphocyte functional antigen 1 (LFA-1) and its cell surface ligand, intercellular adhesion molecule 1 (ICAM-1). It has been suggested that the brain astrocyte can function as a facultative antigen presenting cell (APC). This hypothesis is based upon the ability to induce the expression of the class II MHC antigens on astrocytes, and on their ability to present myelin basic protein to encephalitogenic T-cells in vitro. The best in vivo data showing that astrocytes serve as intracerebral APCs is the finding that astrocytes in multiple sclerosis plaques are DR+ (class II MHC in human). However, it still remains to be resolved whether the in vivo expression of the MHC antigens in disease states is instrumental to antigen presentation
TY - JOUR. T1 - Induction of Alzheimer-specific tau epitope AT100 in apoptotic human fetal astrocytes. AU - Ksiezak-Reding, Hanna. AU - He, Deke. AU - Gordon-Krajcer, Wanda. AU - Kress, Yvonne. AU - Lee, Sunhee. AU - Dickson, Dennis W.. PY - 2000. Y1 - 2000. N2 - In Alzheimers and other neurodegenerative diseases, hyperphosphorylated tau accumulates in affected neuronal and glial cells in the form of paired helical filaments (PHFs). This tau binds antibody AT100, which recognizes the double phosphorylation site (Thr212/Ser214) that is not present in normal biopsy tau. In primary cultures, highly enriched (,98%) in astrocytes of human fetal brain, three polypeptides of 52, 64, and 70 kD showed immunoreactivity with tau antibodies against non-phosphorylated epitopes, accounting for 88, 12, and ,1%, respectively, of the total reactivity. All three polypeptides were phosphorylated at the PHF-1 epitope but not at the epitopes Tau-1, 12E8, AT8, and AT100. Treatment of cultures with okadaic acid ...
TY - JOUR. T1 - Synergistic induction of astrocytic differentiation by factors secreted from meninges in the mouse developing brain. AU - Kawamura, Yoichiro. AU - Katada, Sayako. AU - Noguchi, Hirofumi. AU - Yamamoto, Hiroyuki. AU - Sanosaka, Tsukasa. AU - Iihara, Koji. AU - Nakashima, Kinichi. PY - 2017/11. Y1 - 2017/11. N2 - Astrocytes, which support diverse neuronal functions, are generated from multipotent neural stem/precursor cells (NS/PCs) during brain development. Although many astrocyte-inducing factors have been identified and studied in vitro, the regions and/or cells that produce these factors in the developing brain remain elusive. Here, we show that meninges-produced factors induce astrocytic differentiation of NS/PCs. Consistent with the timing when astrocytic differentiation of NS/PCs increases, expression of astrocyte-inducing factors is upregulated. Meningeal secretion-mimicking combinatorial treatment of NS/PCs with bone morphogenetic protein 4, retinoic acid and leukemia ...
In this study, we focused on four glial proteins that are abundant in amyloid plaques and/or that are known to interact with Abeta: alpha1-antichymotrypsin (ACT), interleukin-1beta (IL-1beta), S100beta, and butyrylcholinesterase (BChE). We examined the ability of these proteins to activate rat cortical astrocyte cultures and to influence the ability of Abeta to activate astrocytes. Treatment of astrocytes with ACT, IL-1beta, or S100beta resulted in glial activation, as assessed by reactive morphology, upregulation of IL-1beta, and production of inducible nitric oxide synthase and nitric oxide. The ability of Abeta to induce astrocyte activation was also enhanced in the presence of each of these three proteins. In contrast, BChE alone did not activate astrocytes and had no effect on Abeta-induced activation ...
Astrocytes, which constitute 40% to 70% of total cells in the CNS [1], perform key regulatory functions critical to brain function. The different CNS cell types are differentially infected with HIV; microglia being highly susceptible, astrocytes moderately restrictive, and neurons highly restrictive. Despite the lack of CD4 receptors, astrocytes become infected via CD4-independent mechanism [6,44]. In line with the earlier studies [1,2], we also found low level of HIV replication in astrocytes compared to microglia. After the initial productive phase, infection subsides to a persistent stage in astrocytes, which goes in hand with reports from other investigators [1,2,32]. Infected astrocytes produce very low levels of virus even in the acute phase in contrast to infection of T-lymphocytes [45,46]. Our results with pseudotyped virus confirm that regardless of the entry routes, there are post-entry blocks to infection in astrocytes. Though the introduction of potent HAART has significantly ...
OASIS is a member of the CREB/ATF family of transcription factors and modulates cell- or tissue-specific unfolded protein response signalling. Here we show that this modulation has a critical role in the differentiation of neural precursor cells into astrocytes. Cerebral cortices of mice specifically deficient in OASIS (Oasis−/−) contain fewer astrocytes and more neural precursor cells than those of wild-type mice during embryonic development. Furthermore, astrocyte differentiation is delayed in primary cultured Oasis−/− neural precursor cells. The transcription factor Gcm1, which is necessary for astrocyte differentiation in Drosophila, is revealed to be a target of OASIS. Introduction of Gcm1 into Oasis−/− neural precursor cells improves the delayed differentiation of neural precursor cells into astrocytes by accelerating demethylation of the Gfap promoter. Gcm1 expression is temporally controlled by the unfolded protein response through interactions between OASIS family members ...
We have used digital fluorescence imaging techniques to explore the interplay between mitochondrial Ca2+ uptake and physiological Ca2+ signaling in rat cortical astrocytes. A rise in cytosolic Ca2+ ([Ca2+]cyt), resulting from mobilization of ER Ca2+ stores was followed by a rise in mitochondrial Ca2+ ([Ca2+]m, monitored using rhod-2). Whereas [Ca2+]cyt recovered within ~1 min, the time to recovery for [Ca2+]m was ~30 min. Dissipating the mitochondrial membrane potential ( Dcm, using the mitochondrial uncoupler carbonyl cyanide p-trifluoromethoxy-phenylhydrazone [FCCP] with oligomycin) prevented mitochondrial Ca2+ uptake and slowed the rate of decay of [Ca2+]cyt transients, suggesting that mitochondrial Ca2+ uptake plays a significant role in the clearance of physiological [Ca2+]cyt loads in astrocytes. Ca2+ signals in these cells initiated either by receptor-mediated ER Ca2+ release or mechanical stimulation often consisted of propagating waves (measured using fluo-3). In response to either ...
When DArcy Wentworth Thompsons On Growth and Form was published 100 years ago, it raised the question of how biological forms arise during development and across evolution. In light of the advances in molecular and cellular biology since then, a succinct modern view of the question states: how do genes encode geometry? Our new special issue is packed with articles that use mathematical and physical approaches to gain insights into cell and tissue patterning, morphogenesis and dynamics, and that provide a physical framework to capture these processes operating across scales.. Read the Editorial by guest editors Thomas Lecuit and L. Mahadevan, as they provide a perspective on the influence of DArcy Thompsons work and an overview of the articles in this issue.. ...
In the astrocyte lineage, Meteorin expression appears to be restricted to relatively immature cell populations. Meteorin expression is gradually lost in GLAST‐expressing astrocytes located in the postnatal cerebral parenchyma (Figure 2K and L), and is not detected in two major types of astrocytes in the adult cerebrum, fibrous astrocytes and protoplasmic astrocytes (Miller and Raff, 1984) (Supplementary Figure 3G). In the developing cerebellum, Meteorin is expressed in the VZ and GLAST‐positive migrating glial precursors. Among three subclasses of astrocytes in the adult cerebellar cortex, bushy protoplasmic astrocytes, smooth protoplasmic astrocytes, and Bergmann glia (Palay and Chan‐Palay, 1974), Meteorin expression is restricted to Bergmann glia (Figure 2M and N) (Supplementary Figure 3H and I). Expression of Meteorin in Bergmann glia may be regulated by neurons that interact with Bergmann glia. For instance, dendritic spines of Purkinje cells were completely enwrapped by Bergmann glial ...
The cells we identify here as primary precursors for new neurons in the adult hippocampus have the characteristics of astrocytes at the light and electron microscope. They contain multiple processes with intermediate filaments rich in GFAP. Results from three independent experiments support this conclusion. First, many proliferating SGL astrocytes rapidly convert to a cell type that is GFAP negative and that possesses characteristics of D cells. Second, anti-mitotic treatment resulted in the elimination of D cells from the SGL, but neurogenesis returned. Because new neurons are born at a time when [3H]thymidine-labeled astrocytes were observed, we infer that astrocytes function as primary precursors. Finally, we show that SGL astrocytes, specifically labeled with an avian retrovirus, give rise to granule neurons. We observed granule neurons at different stages of maturation by killing animals at different survivals after retroviral infection. Some SGL astrocytes remain labeled with thymidine ...
Tenascin-C is an extracellular matrix glycoprotein with trophic and repulsive properties on neuronal cells, involved in migratory processes of immature neurons. Previous reports demonstrated that this molecule is produced and secreted by astrocytes, in vitro after activation by bFGF or in vivo after CNS lesion. In injured brain the expression of tenascin-C has been correlated with the glial reaction since it was observed in regions suffering a dramatic glial proliferation and hypertrophy. In this report we show that the treatment of cultured hippocampal astrocytes with tenascin-C results in an increased fibronectin and NCAM immunoreactivities. In addition, treated astrocytes form longer extensions than control ones. The number of cells as well as the levels of GFAP mRNA and protein immunoreactivity are not modified after tenascin-C treatment. The present changes may, therefore, be related to the modification of the adhesive properties of astrocytes to the substrate. These observations are compatible
Repairing trauma to the central nervous system by replacement of glial support cells is an increasingly attractive therapeutic strategy. We have focused on the less-studied replacement of astrocytes, the major support cell in the central nervous system, by generating astrocytes from embryonic human glial precursor cells using two different astrocyte differentiation inducing factors. The resulting astrocytes differed in expression of multiple proteins thought to either promote or inhibit central nervous system homeostasis and regeneration. When transplanted into acute transection injuries of the adult rat spinal cord, astrocytes generated by exposing human glial precursor cells to bone morphogenetic protein promoted significant recovery of volitional foot placement, axonal growth and notably robust increases in neuronal survival in multiple spinal cord laminae. In marked contrast, human glial precursor cells and astrocytes generated from these cells by exposure to ciliary neurotrophic factor both failed
One barrier to studying astrocytes has been the difficulty of isolating and culturing the mature cell from the brain. Most current protocols isolate precursor cells rather than mature astrocytes. These precursor cells proliferate in culture in the presence of serum, developing a flat, fibroblast-like appearance that bears little resemblance to astrocytes in the brain (see image above). Other isolation methods, such as fluorescence-activated cell sorting, are too harsh to produce viable cells, co-first author Ye Zhang told Alzforum.. To gently isolate mature astrocytes for culturing, Zhang and co-first author Steven Sloan developed an immunopanning protocol. In this procedure, dissociated cells from brain tissue were passed through several culture dishes coated with antibodies to specific cell-surface markers. The first several plates removed unwanted cell types, while the final plate contained anti-HepaCAM to capture astrocytes. After washing off contaminating cells, the authors detached the ...
The 14-3-3 protein family plays critical regulatory roles in signaling pathways in cell division and apoptosis. 14-3-3gamma is mainly expressed in brain. Using primary cultures of cerebral cortical astrocytes, we investigated the relationships between 14-3-3gamma proteins and actin in astrocytes in cell division and under ischemia. Our results showed that endogenous 14-3-3gamma proteins in immature astrocytes appeared filamentous and co-localized with filamentous actin (F-actin). During certain stages of mitosis, 14-3-3gamma proteins first aggregated and then formed a ring-like structure that surrounded the daughter nuclei and enclosed the F-actin. In 4-week-old cultures of astrocytes, 14-3-3gamma proteins appeared as punctate aggregates in the cytoplasm. Under ischemia, 14-3-3gamma proteins formed filamentous structures and were closely associated with F-actin in surviving astrocytes. However, in apoptotic astrocytes, the intensity of immunostaining of 14-3-3gamma proteins in the cytoplasm ...
In cell migration assays, spheroids are seeded on an astrocyte monolayer culture, so the glioma cells do not penetrate the astrocyte culture and the migration is two-dimensional. This is the reason why we considered two layers in the model: one layer is the astrocyte on top of which lies the tumour cell layer. Thus, glioma cells and astrocytes can occupy the same position but on different planes. For all practical purposes, astrocytes in a confluent monolayer culture could be considered as non-motile cells. Time-lapse experiments registered only chaotic non-directional movements of negligible magnitude 1.24±0.36 μm in 5 h.. The rules of motion inside the layer of glioma cells are exactly the same as described before, for migration on a passive substrate: in the control situation we have p+=1, whereas in the treated situation we take p−=0.5. For the sake of coherency, we model the heterotype GJ communication as we did for homotype communication, i.e. with a parameter q which quantifies the ...
Functionally diversified neuronal populations have been efficiently generated from human pluripotent stem cells (hPSCs). rostral-caudal and dorsal-ventral identities with the same morphogens used for neuronal subtype specification generate immature astrocytes that carry distinct homeodomain transcription factors and display phenotypic differences. These human astroglial progenitors and immature astrocytes will be instrumental for studying astrocytes in brain development and function for revealing their roles in disease processes and for developing novel treatments for neurological disorders. INTRODUCTION Astroglial cells are the most abundant cell type in our brain and spinal cord and are now understood to be as important as neurons for brain function1 2 During development astroglial progenitors are specified after neurogenesis even though the identity of the progenitors isnt well described due to R935788 insufficient dependable markers3 4 These progenitors differentiate to immature astrocytes ...
We found that cultured mouse cortical astrocytes display circadian rhythms in extracellular ATP, in agreement with recent results from rat astrocyte cultures, SCN and SCN2.2 cells (Womac et al., 2009). We used a stabilized form of luciferase that allowed long-term recordings of extracellular ATP from the same cells without perturbations that can affect circadian clock-gene expression in astrocytes (Prolo et al., 2005). We found that Clock/Clock, Per1m Per2m, Cry1−/−Cry2−/− and Bmal1−/− astrocytes are arrhythmic, similar to the locomotor behavior deficits of these mice (Vitaterna et al., 1994; van der Horst et al., 1999; Bunger et al., 2000; Zheng et al., 2001). We found that Bmal1, Clock−/+ and Cry1−/−Cry2−/+ glia have abnormal periods, much like the heterozygous mouse behavior. The correlations between rhythmicity in clock genes, extracellular ATP in glia and locomotor behavior suggest they may be tightly related.. Most of the astrocyte cultures deficient for functional ...
The central finding of the present study is that Mt3 plays a key role in the clathrin-dependent endocytosis of Aβ in astrocytes. In Mt3 −/− astrocytes, clathrin-mediated endocytosis, the mechanism responsible for Aβ endocytosis, was markedly decreased, whereas caveolin-mediated endocytosis was not altered. Astrocytes are likely key players in the clearance of extracellular Aβ; thus, our results suggest that changes in the Mt3 expression in astrocytes may have clinical relevance in AD. Taken together with our previous findings that Mt3 helps to maintain lysosomal degradation in astrocytes, the reduction in Mt3 in astrocytes may aggravate Aβ accumulation in the extracellular space.. Early studies showed that AD brain extracts induce more neurite outgrowth in cell cultures than do control brain extracts [27], suggesting upregulation of a growth-inducing factor or downregulation of a growth-inhibitory factor (GIF) in AD brains. The latter was shown to be the case, and a subsequent study ...
To better characterize the electrophysiological properties of neonatal astrocytes, we purposely narrowed the animal age to the dormant P1-3 period for examining potential diversity in ion channel expression among neonatal astrocytes. Interestingly, two electrophysiological phenotypes could be readily identified during this early postnatal age. The neonatal astrocytes in P1 homogeneously show a variably rectifying whole cell current profile, whereas electrophysiologically passive astrocytes (PAs) first appear in P2, and the percentage of PAs rapidly increased from 6.67 % in P2 to 20.83 % at P3. Interestingly, the appearance of PA in mice is 2 days earlier than rats [2], which seemingly follows a longer gestation time in rats (22 day) than mice (20 day).. We show that the passive behavior of neonatal astrocytes is solely attributable to gap junction coupling (Fig. 3). This differs fundamentally from the passive behavior of membrane conductance in mature astrocytes that is caused by intrinsic K+ ...
Neurogenesis is restricted in the adult mammalian brain; most neurons are neither exchanged during normal life nor replaced in pathological situations. We report that stroke elicits a latent neurogenic program in striatal astrocytes in mice. Notch1 signaling is reduced in astrocytes after stroke, and attenuated Notch1 signaling is necessary for neurogenesis by striatal astrocytes. Blocking Notch signaling triggers astrocytes in the striatum and the medial cortex to enter a neurogenic program, even in the absence of stroke, resulting in 850 ± 210 (mean ± SEM) new neurons in a mouse striatum. Thus, under Notch signaling regulation, astrocytes in the adult mouse brain parenchyma carry a latent neurogenic program that may potentially be useful for neuronal replacement strategies. ...
Astrocytes are now recognized as dynamic signaling elements in the brain. Bidirectional communication between neurons and astrocytes involves integration of neuronal inputs by astrocytes and release of gliotransmitters that modulate neuronal excitability and synaptic transmission. The ovarian steroid hormone, 17\beta-estradiol, in addition to its rapid actions on neuronal electrical activity can rapidly alter astrocyte intracellular calcium concentration $([Ca^{2+}]_i)$ through a membrane-associated estrogen receptor. Using calcium imaging and electrophysiological techniques, we investigated the functional consequences of acute treatment with estradiol on astrocyte-astrocyte and astrocyte-neuron communication in mixed hippocampal cultures. Mechanical stimulation of an astrocyte evoked a $[Ca^{2+}]_i$ rise in the stimulated astrocyte, which propagated to the surrounding astrocytes as a $[Ca^{2+}]_i$ wave. Following acute treatment with estradiol, the amplitude of the $([Ca^{2+}]_i)$ elevation in ...
Astrocytes are the most abundant and functionally diverse glial population in the vertebrate central nervous system (CNS). However, the mechanisms underlying astrocyte specification are poorly understood. It is well established that cellular diversification of neurons in the embryo is generated by position-dependent extrinsic signals and combinatorial interactions of transcription factors that direct specific cell fates by suppressing alternative fates. It is unknown whether a comparable process determines embryonic astrocyte identity. Indeed, astrocyte development is generally thought to take place in a position-independent manner. Here we show multiple functions of Stem cell leukaemia (Scl, also known as Tal1), which encodes a basic helix-loop-helix (bHLH) transcription factor, in the regulation of both astrocyte versus oligodendrocyte cell fate acquisition and V2b versus V2a interneuron cell fate acquisition in the p2 domain of the developing vertebrate spinal cord. Our findings demonstrate a
Aquaporin-4 (AQP4) is the predominant water channel in brain and is selectively expressed in astrocytes. Astrocytic endfoot membranes exhibit tenfold higher densities of AQP4 than non-endfoot membranes, making AQP4 an excellent marker of astrocyte polarization. Loss of astrocyte polarization is known to compromise astrocytic function and to be associated with impaired water and K+ homeostasis. Here we investigate by a combination of light and electron microscopic immunocytochemistry whether amyloid deposition is associated with a loss of astrocyte polarization, using AQP4 as a marker. We used the tg-ArcSwe mouse model of Alzheimers disease, as this model displays perivascular plaques as well as plaques confined to the neuropil. 3D reconstructions were done to establish the spatial relation between plaques and astrocytic endfeet, the latter known to contain the perivascular pool of AQP4. Changes in AQP4 expression emerge just after the appearance of the first plaques. Typically, there is a loss ...
This cellular imaging study in animal models will explore whether two genetically determined forms of autism spectrum disorder (ASD) have similar deleterious alterations in star-shaped cells, called astrocytes, that adversely affect brain development. Two genetic forms of ASD are Retts syndrome, which occurs almost exclusively in girls, and Fragile X syndrome, which occurs predominately in boys. Prior research showed that defects occur in neurons. More recent research indicates that defects occur as well in other types of cells in the brain, including astrocytes. While there are billions of nerve cells in the brain, there are even more astrocytes. Research suggests that astrocytes can produce both advantageous and deleterious effects. In the developing brain, astrocytes have a key role in regulating nerve cells functions. If astrocytes are altered, however, they may adversely affect brain development. The investigators hypothesize that both in Retts syndrome and Fragile X syndrome, as well ...
There is now growing evidence that astrocytes, like neurons, can release transmitters. One transmitter that in a vast number of studies has been shown to be released from astrocytes is glutamate. Although asytrocytic glutamate may be released by several mechanisms, the evidence in favor of exocytosis is most compelling. Astrocytes may respond to neuronal activity by such exocytotic release of glutamate. The astrocyte derived glutamate can in turn activate neuronal glutamate receptors, in particular N-methyl-D-aspartate (NMDA) receptors. Here we review the morphological data supporting that astrocytes possess the machinery for exocytosis of glutamate. We describe the presence of small synaptic-like microvesicles, SNARE proteins and vesicular glutamate transporters in astrocytes, as well as NMDA receptors situated in vicinity of the astrocytic vesicles.
The pathophysiology of a traumatic brain injury (TBI) involves the dysfunction of the blood-brain barrier (BBB). The lumen of the BBB is lined with cerebrovascular endothelial cells (CVEC) that are ensheathed with perivascular astrocyte endfeet. We investigated the cellular response of human-astrocytes and human-CVEC following trauma in vitro. Astrocytes and CVEC were subjected to a concussive injury (CI; mechanical stretch), then assessed for markers of injury (monolayer retraction) and activation (mitogen-activated protein kinases (MAPK) phosphorylation). CI induces astrocyte monolayer retraction and activation, with predominant phosphorylation of JNK1/2 MAPK. Interfering with JNK1/2 activation (selective JNK inhibitors) reduces trauma-induced astrocyte retraction. On the contrary, CI does not induce CVEC retraction, however up-regulates CVEC pro-adhesive phenotype resulting in increased polymorphonuclear leukocyte (PMN) adhesion. These findings indicate that CI elicits differential BBB cell responses
Astrocytes are diverse in morphology and molecular makeup (1, 2), potentially enabling them to provide for the varying needs of their diverse neuronal counterparts (3). What accounts for and maintains astrocyte heterogeneity are only beginning to be explored. One possibility is that the signals specifying astrocyte subpopulations might operate only during the critical phases of development, after which the cell is hardwired. Alternatively, these signals might be operational at all times. On page 849 of this issue, Farmer et al. (4) reveal that neuronal signals drive the molecular programs of astrocytes even during adult stages of life. This challenges the idea that astrocyte function is hardwired during development and provides a new mechanism for cellular plasticity in the adult brain. ...
We used the pH-sensitive fluorescent dye BCECF to study intracellular pH (pHi) regulation in primary cultures of rat astrocytes and C6 glioma cells. Both cell types contain three pH-regulating transporters: (1) alkalinizing Na+/H+ exchange; (2) alkalinizing Na+ + HCO3 −/Cl−exchange; and (3) acidifying Cl−/HCO3− exchange. Na+/H+ exchange was most evident in the absence of CO2; recovery from acidification was Na+ dependent and amiloride sensitive. Exposure to CO2 caused a cell alkalinization that was inhibited by DIDS, dependent on external Na+, and inhibited 75% in the absence of Cl− (thus mediated by Na+ + HCO3−/Cl− exchange). When pHi was increased above the normal steady-state pHi, a DIDS-inhibitable and Na+ -independent acidifying recovery was evident, indicating the presence of Cl− /HCO3−exchange. Astrocytes, but not C6 cells, contain a fourth pH-regulating transporter, Na+ −HCO3− cotransport; in the presence of CO2, depolarization caused an alkalinization of 0.12 +− 0.01 (n
Ischemic stroke, a major cause of mortality, is frequently accompanied by life-threatening cerebral edema. Aquaporin-4 (Aqp4), an astrocytic transmembrane water channel, is an important molecular contributor to cerebral edema formation. Past studies of Aqp4 expression and localization after ischemia examined grey matter exclusively. However, as white matter astrocytes differ developmentally, physiologically, and molecularly from grey matter astrocytes, we hypothesized that functionally important regional heterogeneity exists in Aqp4 expression and subcellular localization following cerebral ischemia. Subcellular localization of Aqp4 was compared between cortical and white matter astrocytes in postmortem specimens of patients with focal ischemic stroke versus controls. Subcellular localization and expression of Aqp4 was examined in rats subjected to experimental stroke. Volumetric analysis was performed on the cortex and white matter of rats subjected to experimental stroke. Following cerebral ischemia,
Despite successful management of ruptured intracranial aneurysm following subarachnoid hemorrhage (SAH), delayed cerebral ischemia (DCI) remains the main cause of high mortality and morbidity in patients who survive the initial bleeding. Astrocytes play a key role in neurovascular coupling. Therefore, changes in the neurovascular unit including astrocytes following SAH may contribute to the development of DCI and long-term complications. In this study, we characterized morphological changes in hippocampal astrocytes following experimental SAH, with special emphasis on glia-vascular cross-talk and hippocampal volume changes. Four days after induction of SAH or sham-operation in mice, their hippocampal volumes were determined by magnetic resonance imaging (MRI) and histological/stereological methods. Glial fibrillary acid protein (GFAP) immunostained hippocampal sections were examined by stereological techniques to detect differences in astrocyte morphology, and global spatial sampling method was ...
TY - JOUR. T1 - The protective effects of coumestrol against amyloid-beta peptide- and lipopolysaccharide-induced toxicity on mice astrocytes. AU - Liu, Man Hai. AU - Tsuang, Fon Yih. AU - Sheu, Shiow Yunn. AU - Sun, Jui Sheng. AU - Shih, Chi Ming. PY - 2011/7. Y1 - 2011/7. N2 - Objectives: Estrogen replacement therapy can decrease the risk of developing Alzheimers disease. Phytoestrogens have been proposed as potential alternatives to estrogen replacement therapy. The purpose of this study was to evaluate the in vitro protective effects of coumestrol on mice astrocytes. Methods: Different concentrations of coumestrol were tested for their protective efficacy against two toxic insults, lipopolysaccharide (LPS) and amyloid-beta peptide, on astrocytes. The mitochondrial activity of astrocytes was determined, and the protective efficacy and pathway were examined by their specific gene expression and protein change. Results: The results showed that coumestrol induced a modest but significant ...
Astrocyte activation is a characteristic response to injury in the central nervous system, and can be either neurotoxic or neuroprotective, while the regulation of both roles remains elusive. To decipher the regulatory elements controlling astrocyte-mediated neurotoxicity in glaucoma, we conducted a systems-level functional analysis of gene expression, proteomic and genetic data associated with reactive optic nerve head astrocytes (ONHAs). Our reconstruction of the molecular interactions affected by glaucoma revealed multi-domain biological networks controlling activation of ONHAs at the level of intercellular stimuli, intracellular signaling and core effectors. The analysis revealed that synergistic action of the transcription factors AP-1, vitamin D receptor and Nuclear Factor-kappaB in cross-activation of multiple pathways, including inflammatory cytokines, complement, clusterin, ephrins, and multiple metabolic pathways. We found that the products of over two thirds of genes linked to glaucoma by
TY - JOUR. T1 - Glutamate transporter function of rat hippocampal astrocytes is impaired following the global ischemia. AU - Yeh, Tu Hsueh. AU - Hwang, Hwa Min. AU - Chen, Jin Jung. AU - Wu, Tony. AU - Li, Allen Hon Lun. AU - Wang, Hung Li. PY - 2005/4. Y1 - 2005/4. N2 - Astroglial glutamate transporters, GLT-1 and GLAST, play an essential role in removing released glutamate from the extracellular space and are essential for maintaining a low concentration of extracellular glutamate in the brain. It was hypothesized that impaired function of glial glutamate transporters induced by transient global ischemia may lead to an elevated level of extracellular glutamate and subsequent excitotoxic neuronal death. To test this hypothesis, in the present study, we performed whole-cell patch-clamp recording of hippocampal CA1 astrocytes in control or postischemic slices, and measured glutamate transporter activity by recording glutamate-evoked transporter currents. Six to 24 h after global ischemia, maximal ...
Objective:To investigate the expression of two-pore domain potassium channel-TREK-1 on primary cultured neurons and astrocytes and the temporal changes of TREK-1 expression in astrocytes under hypoxia insult.Methods: The cortical neurons and astrocytes were cultured.The expression of TREK-1 in cultured neurons and astrocytes were analyzed by double immunofluorescence staining.The temporal changes of TREK-1 expression in astrocytes under hypoxia insults were detected by Real-time PCR.Results: The TREK-1 immuno-reactivity was expressed on both the neurons and astrocytes under normal condition.During hypoxia insult,the TREK-1 expression on astrocyte increases at early phases and decreases gradually at late phase.Conclusion: The TREK-1 immunoreactivity is expressed on both the neurons and astrocytes.In astrocytes under hypoxia,there are temporal changes on TREK-1 expression.
Glial Fibrillary Acid Protein (GFAP) Mouse, Alexa Fluor 488, Clone: GA5, eBioscience™ 25μg; Alexa Fluor 488 Glial Fibrillary Acid Protein (GFAP) Mouse, Alexa...
TY - JOUR. T1 - Leucine Zipper-Bearing Kinase Is a Critical Regulator of Astrocyte Reactivity in the Adult Mammalian CNS. AU - Chen, Meifan. AU - Geoffroy, Cédric G.. AU - Meves, Jessica M.. AU - Narang, Aarti. AU - Li, Yunbo. AU - Nguyen, Mallorie T.. AU - Khai, Vung S.. AU - Kong, Xiangmei. AU - Steinke, Christopher L.. AU - Carolino, Krislyn I.. AU - Elzière, Lucie. AU - Goldberg, Mark P.. AU - Jin, Yishi. AU - Zheng, Binhai. PY - 2018/3/27. Y1 - 2018/3/27. N2 - Reactive astrocytes influence post-injury recovery, repair, and pathogenesis of the mammalian CNS. Much of the regulation of astrocyte reactivity, however, remains to be understood. Using genetic loss and gain-of-function analyses in vivo, we show that the conserved MAP3K13 (also known as leucine zipper-bearing kinase [LZK]) promotes astrocyte reactivity and glial scar formation after CNS injury. Inducible LZK gene deletion in astrocytes of adult mice reduced astrogliosis and impaired glial scar formation, resulting in increased ...
Astrocytes play many roles essential for normal brain activity. The ability of these cells to recover after temporary focal cerebral ischemia is likely to be one important determinant of the extent of brain dysfunction and tissue damage. We have assessed astrocytic function based on the incorporation of radiolabel from 1-14C-acetate into glutamine at 1 hour of recirculation after middle cerebral artery occlusion for 2 or 3 hours in rats. There were marked differences in the response between subregions within the tissue subjected to ischemia, but the overall pattern of changes was similar after each ischemic period. The striatum, which forms part of the severely ischemic focal tissue during arterial occlusion, showed a large (44% to 68%) decrease in glutamine labeling compared with equivalent tissue from the contralateral hemisphere. In contrast, 14C-glutamine content was not significantly altered in perifocal tissue in the cerebral cortex, which was subjected to more moderate ischemia. Cortical ...
Purpose To determine whether optic nerve head (ONH) astrocytes, a key cellular component of glaucomatous neuropathy, exhibit differential gene expression in primary cultures of astrocytes from normal African American (AA) donors compared to astrocytes from normal Caucasian American (CA) donors. Methods We used oligonucleotide Affymetrix microarray (HG U133A & HG U133A 2.0 chips) to compare gene expression levels in cultured ONH astrocytes from twelve CA and twelve AA normal age matched donor eyes. Chips were normalized with Robust Microarray Analysis (RMA) in R using Bioconductor. Significant differential gene expression levels were detected using mixed effects modeling and Statistical Analysis of Microarray (SAM). Functional analysis and Gene Ontology were used to classify differentially expressed genes. Differential gene expression was validated by quantitative real time RT-PCR. Protein levels were detected by Western blots and ELISA. Cell adhesion and migration assays tested physiological responses.
Purpose: Retinal neovascularization has been intensively investigated in the mouse model of oxygen-induced retinopathy (OIR). The role of astrocytes for vascular loss and reactive angiogenesis, however, is not fully understood. Due to their stellar morphology, only semi-quantitative analysis has yet been possible. This study presents data on the kinetics of retinal astrocytes in relation to changes in the vascular bed during the OIR model based on a quantitative approach.. Methods: In the OIR model, mice are exposed to 75% oxygen from post-natal day 7 (P7) to P12 (hyperoxic phase). After return to room air, the avascular area of the retina becomes hypoxic and responds with physiologic and pathologic revascularization from P12 to P21. In this study, reporter mice expressing histone-bound GFP under the control of the Pdgfra promoter were used to identify astrocyte nuclei in the murine retina. The astrocytic density across the retina was determined at different times during the OIR model using the ...
Background The efficient derivation of mature (Hb9+) motor neurons from embryonic stem cells is a sought-after goal in the understanding, and potential treatment, of motor neuron diseases. Conditions that promote the robust generation of motor neuron progenitors from embryonic stem cells and that promote the survival of differentiated motor neurons ex vivo are likely, therefore, to be critical in future biological/therapeutic/screening approaches. Previous studies have shown that astrocytes have a protective effect on differentiated motor neurons (in vivo and ex vivo), but it remains unclear whether astrocytes also play a beneficial role in the support of motor neuron progenitors. Here we explore the effect of murine astrocyte-conditioned medium on monolayer cultures of mouse embryonic stem cell-derived motor neuron progenitors. Results Our data show that wild-type astrocyte-conditioned medium significantly increases the number of Olig2+/Hb9- progenitors, which subsequently differentiate into ...
Neurons have intrinsic capability to regenerate after lesion, though not spontaneously. Spinal cord injury (SCI) causes permanent neurological impairments partly due to formation of a glial scar that is composed of astrocytes and microglia. Astrocytes play both beneficial and detrimental roles on axonal re-growth, however, their precise role after SCI is currently under debate. We analyzed molecular changes in astrocytes at multiple stages after two SCI severities using cell-specific transcriptomic analyses. We demonstrate that astrocyte response after injury depends on both time after injury and lesion severity. We then establish that injury induces an autologous astroglial transdifferentiation where over 10 % of astrocytes express classical neuronal progenitor markers including βIII-tubulin and doublecortin with typical immature neuronal morphology. Lineage tracing confirmed that the origin of these astrocytes is resident mature, rather than newly formed astrocytes. Astrocyte-derived neuronal
TY - JOUR. T1 - Interleukin-1β protects astrocytes against oxidant-induced injury via an NF-κB-Dependent upregulation of glutathione synthesis. AU - He, Yan. AU - Jackman, Nicole A.. AU - Thorn, Trista L.. AU - Vought, Valarie E.. AU - Hewett, Sandra J.. N1 - Publisher Copyright: © 2015 Wiley Periodicals, Inc. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.. PY - 2015/9. Y1 - 2015/9. N2 - Astrocytes produce and export the antioxidant glutathione (GSH). Previously, we found that interleukin-1β (IL-1β) enhanced the expression of astrocyte system xc-, the transporter that delivers the rate-limiting substrate for GSH synthesis-cyst(e)ine. Herein, we demonstrate directly that IL-1β mediates a time-dependent increase in extracellular GSH levels in cortical astrocyte cultures, suggesting both enhanced synthesis and export. This increased GSH production was blocked by inhibition of nuclear factor-κB (NF-κB) activity but not by inhibition of p38 MAPK. To determine whether this ...
AbstractBackgroundNeurons have intrinsic capability to regenerate after lesion, though not spontaneously. Spinal cord injury (SCI) causes permanent neurological impairments partly due to formation of a glial scar that is composed of astrocytes and microglia. Astrocytes play both beneficial and detrimental roles on axonal re-growth, however, their precise role after SCI is currently under debate.MethodsWe analyzed molecular changes in astrocytes at multiple stages after two SCI severities using cell-specific transcriptomic analyses.ResultsWe demonstrate that astrocyte response after injury depends on both time after injury and lesion severity. We then establish that injury induces an autologous astroglial transdifferentiation where over 10 % of astrocytes express classical neuronal progenitor markers including βIII-tubulin and doublecortin with typical immature neuronal morphology. Lineage tracing confirmed that the origin of these astrocytes is resident mature, rather than newly formed astrocytes.
TY - JOUR. T1 - Iron uptake in quiescent and inflammation-activated astrocytes. T2 - A potentially neuroprotective control of iron burden. AU - Pelizzoni, Ilaria. AU - Zacchetti, Daniele. AU - Campanella, Alessandro. AU - Grohovaz, Fabio. AU - Codazzi, Franca. PY - 2013/8. Y1 - 2013/8. N2 - Astrocytes play a crucial role in proper iron handling within the central nervous system. This competence can be fundamental, particularly during neuroinflammation, and neurodegenerative processes, where an increase in iron content can favor oxidative stress, thereby worsening disease progression. Under these pathological conditions, astrocytes undergo a process of activation that confers them either a beneficial or a detrimental role on neuronal survival. Our work investigates the mechanisms of iron entry in cultures of quiescent and activated hippocampal astrocytes. Our data confirm that the main source of iron is the non-transferrin-bound iron (NTBI) and show the involvement of two different routes for its ...
Optic nerve regeneration (ONR) following injury is a model for central nervous system regeneration. In zebrafish, ONR is rapid - neurites cross the lesion and enter the optic tectum within 7 days; in mammals regeneration does not take place unless astrocytic reactivity is suppressed. Glial fibrillary acidic protein (GFAP) is used as a marker for retinal and optic nerve astrocytes in both fish and mammals, even though it has long been known that astrocytes of optic nerves in many fish, including zebrafish, express cytokeratins and not GFAP. We used immunofluorescence to localize GFAP and cytokeratin in wild-type zebrafish and transgenic zebrafish expressing green fluorescent protein (GFP) under control of a GFAP promoter to determine the pattern of expression of intermediate filaments in retina and optic nerve. GFAP labeling and GFAP gene expression as indicated by GFP fluorescence was found only in the Müller glial cells of the retina. Within Müller cells, GFP fluorescence filled the entire cell while
BACKGROUND: Reactive astrogliosis is a ubiquitous but poorly understood hallmark of central nervous system pathologies such as trauma and neurodegenerative diseases. In vitro and in vivo studies have identified proinflammatory cytokines and chemokines as mediators of astrogliosis during injury and disease; however, the molecular mechanism remains unclear. In this study, we identify astrocyte elevated gene-1 (AEG-1), a human immunodeficiency virus 1 or tumor necrosis factor alpha-inducible oncogene, as a novel modulator of reactive astrogliosis. AEG-1 has engendered tremendous interest in the field of cancer research as a therapeutic target for aggressive tumors. However, little is known of its role in astrocytes and astrocyte-mediated diseases. Based on its oncogenic role in several cancers, here we investigate the AEG-1-mediated regulation of astrocyte migration and proliferation during reactive astrogliosis. METHODS: An in vivo brain injury mouse model was utilized to show AEG-1 induction ...
Background: Neurons have intrinsic capability to regenerate after lesion, though not spontaneously. Spinal cord injury (SCI) causes permanent neurological impairments partly due to formation of a glial scar that is composed of astrocytes and microglia. Astrocytes play both beneficial and detrimental roles on axonal re-growth, however, their precise role after SCI is currently under debate. Methods: We analyzed molecular changes in astrocytes at multiple stages after two SCI severities using cell-specific transcriptomic analyses. Results: We demonstrate that astrocyte response after injury depends on both time after injury and lesion severity. We then establish that injury induces an autologous astroglial transdifferentiation where over 10 % of astrocytes express classical neuronal progenitor markers including beta III-tubulin and doublecortin with typical immature neuronal morphology. Lineage tracing confirmed that the origin of these astrocytes is resident mature, rather than newly formed ...
Albrecht, J., Talbot, M., Kimelberg, H.K., Aschner, M. (1993) The role of sulfhydryl groups and calcium in the mercuric chloride-induced inhibition of glutamate uptake in rat primary astrocyte cultures. Brain Res 607, 249-254.. Anderson, C.M., Swanson, R.A. (2000) Astrocyte glutamate transport: review of properties, regulation, and physiological functions. Glia 32, 1-14.. Aschner, M., Yao, C.P., Allen, J.W., Tan, K.H. (2000) Methylmercury alters glutamate transport in astrocytes. Neurochem Int 37, 199-206.. Balazs, R. (2006) Trophic effect of glutamate. Curr Top Med Chem 6, 961-968.. Brookes, N., Kristt, D.A. (1989) Inhibition of amino acid transport and protein synthesis by HgCl2 and methylmercury in astrocytes: selectivity and reversibility. J Neurochem 53, 1228-1237.. Ceccatelli, S., Dare, E., Moors, M. (2010) Methylmercury-induced neurotoxicity and apoptosis. Chem Biol Interact 188, 301-308.. Choi, D.W. (1992) Excitotoxic cell death. J Neurobiol 23, 1261-1276.. Feng, S., Xu, Z., Liu, W., Li, ...
Background: HIV-1 infected individuals are under chronic exposure to reactive oxygen species (ROS) considered to be instrumental in the progression of AIDS and the development of HIV-1 associated dementia (HAD). Astrocytes support neuronal function and protect them against cytotoxic substances including ROS. The protein HIV-1 Nef, a progression factor in AIDS pathology is abundantly expressed in astrocytes in patients with HAD, and thus may influence its functions. Results: Endogenous expressed HIV-1 Nef leads to increased sensitivity of human astrocytes towards exogenous hydrogen peroxide but not towards TNF-alpha. Cell death of nef-expressing astrocytes exposed to 10 mu M hydrogen peroxide for 30 min occurred within 4 h. Conclusion: HIV-1 Nef may contribute to neuronal dysfunction and the development of HAD by causing death of astrocytes through decreasing their tolerance for hydrogen peroxide. ...
Abstract: A glutamate hypothesis of schizophrenia emerged based on pharmacological evidence that N-methyl-D-aspartate (NMDA) receptor antagonists, such as phencyclidine (PCP), can induce symptoms similar to those seen in schizophrenia. Subsequently, abnormal expression of various neuronal molecules associated with the glutamate synapse has been reported in schizophrenia. Astrocytes, a prominent glial cell in the brain, play a significant role in maintaining the structure and integrity of neural tissue and in facilitating excitatory neurotransmission, therefore, any breakdown in the structure or function of astrocytes could disrupt neuronal signaling and disturb brain function. I studied structural and functional molecules in astrocytes to determine 1) whether astrocytes are themselves globally compromised in schizophrenia, and 2) whether abnormal expression of glutamatergic molecules in astrocytes could be a contributing factor to brain dysfunction in this illness. I examined the expression of ...
TY - JOUR. T1 - D-serine, an endogenous synaptic modulator. T2 - Localization to astrocytes and glutamate-stimulated release. AU - Schell, Michael J.. AU - Molliver, Mark E.. AU - Snyder, Solomon H.. PY - 1995/4/25. Y1 - 1995/4/25. N2 - Using an antibody highly specific for D-serine conjugated to glutaraldehyde, we have localized endogenous D-serine in rat brain. Highest levels of D-serine immunoreactivity occur in the gray matter of the cerebral cortex, hippocampus, anterior olfactory nucleus, olfactory tubercle, and amygdala. Localizations of D-serine immunoreactivity correlate closely with those of D-serine binding to the glycine modulatory site of the N-methyl-D- aspartate (NMDA) receptor as visualized by autoradiography and are inversely correlated to the presence of D-amino acid oxidase. D-Serine is enriched in process-bearing glial cells in neuropil with the morphology of protoplasmic astrocytes. In glial cultures of rat cerebral cortex, D-serine is enriched in type 2 astrocytes. The ...
Our data also shed light on functional differences between neural progenitors and differentiated astrocytes. Adult mammalian neural stem cells of the SVZ carry features of astrocytes such as the expression of glial fibrillary acidic protein (GFAP) or the astrocyte-specific glutamate transporter (GLAST) (Ninkovic and Götz, 2007; Wang and Bordey, 2008), and are sometimes also referred to as the astrocytes of the SVZ. We therefore compared receptor profiles and induced signaling pathways between the cultured neural progenitors and cultured astrocytes. The GFAP-positive progenitor cells investigated in this study were multipotential and expressed the stem-cell marker nestin as well as the type-B cell-associated ectonucleotidases NTPDase2 and TNAP (Mishra et al., 2006; Langer et al., 2007), suggesting that they represent type-B cell-like neural precursors. Both RT-PCR and pharmacological experiments suggest that cultured astrocytes express a variety of P2Y and P2X receptors (Jacques-Silva et al., ...
Clone REA335 recognizes the human, mouse, and rat glial fibrillary acidic protein (GFAP), the main intermediate filament protein in mature astrocytes and an important component of the cytoskeleton in astrocytes during development. GFAP is expressed exclusively in astrocytes in the central nervous system. It has been shown to be involved in astrocyte functions, which are important during regeneration, synaptic plasticity, and reactive gliosis. Moreover, different subpopulations of astrocytes have been identified, which are likely to have distinctive tasks in brain physiology and pathology, and which are not only classified by their spatial and temporal appearance, but also by their specific expression of intermediate filaments, including distinct GFAP isoforms. Additional information: Clone REA335 displays negligible binding to Fc receptors. - Österreich
Supplementary MaterialsESM 1: (PDF 316?kb) 10753_2019_1029_MOESM1_ESM. GFAP in astrocytes and facilitated the creation of inflammatory chemokines and cytokines. Activation of astrocytes by CTGF can be within an autocrine way. Based on the total outcomes of Boyden chamber assay, CTGF improved the recruitment of peripheral bloodstream mononuclear cells (PBMCs) by reactive astrocytes. Besides, CTGF-mediated activation of astrocytes and enhancement of inflammatory response could be terminated from the inhibitor of ASK1 or p38 and JNK. Therefore, our data recommended that CTGF could activate astrocytes within an autocrine way and promote astrocyte-mediated inflammatory response by Cladribine triggering the ASK1-p38/JNK-NF-B/AP-1 pathways in astrocytes. Collectively, our research provided proof that astrocyte-secreted CTGF acts as an amplifier of neuroinflammatory and may be considered a potential focus on for alleviating TBI-induced swelling. Electronic supplementary materials The online edition of ...
The central nervous system (CNS) is arguably the most important part of the human body. It includes the brain and the spinal cord. The brain is widely believed to be where all our thought originate. It compares and contrasts. It strings together words and paragraphs. It helps us to understand and communicate with the world around us. Given the complexity of this remarkable organ, it is hardly surprising that we are still uncovering its secrets. One such secret is the important role of astrocytes.. The brain isnt only occupied by neurons. Glial cells are also a local inhabitant. Though long thought to be little more than the neurons sidekicks, we now know that glial cells are a crucial component of CNS operations. Astrocytes are one of four identified glial cells in the CNS. Two additional varieties hang out in the periphery nervous system.. Astrocytes are essential for maintaining homeostasis in the CNS. They also play a role In brain defense and rejuvenation. Their malfunction or retardation ...
Cell culture: monocultures. Primary human fetal astrocyte cultures were established from 3 different brains as previously described (67). We confirmed an identical in vitro phenotype of commercially available cells (Lonza) and cross-referenced these to previous phenotypes. To establish human CD3+ T lymphocyte cultures from human blood of healthy donors, density centrifugation using Ficoll-Paque PLUS (GE Healthcare) was initially performed to isolate peripheral blood mononuclear cells (PBMCs) from whole blood. Six milliliters of whole blood containing acid citrate dextrose anticoagulant (Biological Specialty Corp.) was diluted with an equal volume of HBSS (Mediatech Inc.) and carefully layered in 15-ml tubes prefilled with 4 ml of density gradient medium. Tubes were centrifuged 40 minutes at 900 relative centrifugal force (RCF). PBMCs were collected by transfer pipette and afterward washed 2-3 times in HBSS (Mediatech Inc.) and centrifuged 15 minutes at 250 RCF. Human CD3+ T lymphocytes were then ...
Cell culture: monocultures. Primary human fetal astrocyte cultures were established from 3 different brains as previously described (67). We confirmed an identical in vitro phenotype of commercially available cells (Lonza) and cross-referenced these to previous phenotypes. To establish human CD3+ T lymphocyte cultures from human blood of healthy donors, density centrifugation using Ficoll-Paque PLUS (GE Healthcare) was initially performed to isolate peripheral blood mononuclear cells (PBMCs) from whole blood. Six milliliters of whole blood containing acid citrate dextrose anticoagulant (Biological Specialty Corp.) was diluted with an equal volume of HBSS (Mediatech Inc.) and carefully layered in 15-ml tubes prefilled with 4 ml of density gradient medium. Tubes were centrifuged 40 minutes at 900 relative centrifugal force (RCF). PBMCs were collected by transfer pipette and afterward washed 2-3 times in HBSS (Mediatech Inc.) and centrifuged 15 minutes at 250 RCF. Human CD3+ T lymphocytes were then ...
Cambridge, MA, December 11, 2018 - Astrocyte Pharmaceuticals Inc., a privately held pharmaceutical company, today announced that Jeffrey L. Saver, M.D., has joined the companys Scientific Advisory Board and will chair the companys Clinical Advisory Board. Astrocyte Pharmaceuticals is developing small molecule therapeutics for the treatment of brain injuries, including patients who have suffered a stroke, traumatic brain injury (TBI) or concussion.. Dr. Saver is a recognized international thought leader on cerebrovascular research and treatments, with impressive experience in designing and leading multiple, successful, innovative clinical studies in stroke, said William Korinek, CEO at Astrocyte Pharmaceuticals. We are excited to have Dr. Saver chair our Clinical Advisory Board that will design the optimal clinical studies to assess AST-004s efficacy in human patients.. Dr. Jeffrey Saver is Vice-Chair and Professor of Neurology at the David Geffen School of Medicine at UCLA and has been ...
The study in mice, by neuroscientists at Tufts University School of Medicine, determined that astrocytes play a critical role in the spread of damage following stroke.. The National Heart Foundation reports that ischemic strokes account for 87% of strokes in the United States. Ischemic strokes are caused by a blood clot that forms and travels to the brain, preventing the flow of blood and oxygen.. Even when blood and oxygen flow is restored, however, neurotransmitter processes in the brain continue to overcompensate for the lack of oxygen, causing brain cells to be damaged. The damage to brain cells often leads to health complications including visual impairment, memory loss, clumsiness, moodiness, and partial or total paralysis.. Research and drug trials have focused primarily on therapies affecting neurons to limit brain cell damage. Phil Haydons group at Tufts University School of Medicine have focused on astrocytes, a lesser known type of brain cell, as an alternative path to understanding ...
According to previous studies, miRNAs affect astrogliosis and astrocyte proliferation through targetting diverse downstream genes [22,26]. To investigate the mechanism by which BDNF affects NHA proliferation, we used online tools including Tarbase and miRWalk to search for the candidate miRNAs which might regulate BDNF expression. After cross-contrast with the results of two software predictions, 14 candidate miRNAs were chosen for further verification (miR-15b, miR-497, miR-211, miR-206, miR-195, miR-204, miR-1s, miR-382, miR-613, miR-15a, miR-16, miR-103a, miR-182, and miR-107, Figure 3A). Upon LPS stimulation, the expression of the indicated candidate miRNAs was monitored; amongst all the candidate miRNAs, miR-211 expression was inhibited by LPS stimulation in a dose-dependent manner (Figure 3B). Next, we verified miR-211 regulation of BDNF using qRT-PCR and Western blot assays. In miR-211 mimics transfected NHAs, BDNF mRNA and protein levels were significantly reduced, whereas miR-211 ...
Lesions and neurologic disability in inflammatory CNS diseases such as multiple sclerosis (MS) result from the translocation of leukocytes and humoral factors from the vasculature, first across the endothelial blood-brain barrier (BBB) and then across the astrocytic glia limitans (GL). Factors secreted by reactive astrocytes open the BBB by disrupting endothelial tight junctions (TJs), but the mechanisms that control access across the GL are unknown. Here, we report that in inflammatory lesions, a second barrier composed of reactive astrocyte TJs of claudin 1 (CLDN1), CLDN4, and junctional adhesion molecule A (JAM-A) subunits is induced at the GL. In a human coculture model, CLDN4-deficient astrocytes were unable to control lymphocyte segregation. In models of CNS inflammation and MS, mice with astrocyte-specific Cldn4 deletion displayed exacerbated leukocyte and humoral infiltration, neuropathology, motor disability, and mortality. These findings identify a second inducible barrier to CNS entry ...
0066]Astroglia cells, i.e. non neoplastic embryonal astrocyte cell line of the rat [Chamaon, K., Kirches, E., Kanakis, D., Braeuninger, S., Dietzmann, K., and Mawrin, C. (2005). Regulation of the pituitary tumor transforming gene by insulin-like-growth factor-I and insulin differs between malignant and non-neoplastic astrocytes. Biochem Biophys Res Commun 331, 86-92] were cultivated on glass cover slips coated with poly-D-lysin at the bottom of culture dishes at 37° C. during 18 hours (5% CO2). 2 ml DMEM (PAA Laboratories GmbH Pasching, Austria) were used as the culture medium in each reaction and the sowing density was 0.3×106 cells/2 ml. First, the cell cultures were pre-incubated in different concentrations (1.0; 5.0 or 25.0 μM) of minocycline hydrochloride or pentaacetyl cyclin (Formula II) during 30 minutes. The sole addition of the solvent DMSO (2 μl/culture dish) under identical incubation conditions was used as the untreated control. Then, 1.0 or 3.0 mM H2O2 (final concentration) was ...
The type beta transforming growth factors (TGF) are potent regulators of the growth and functions of lymphocytes and macrophages. Recently the human glioblastoma cell line 308 was shown to produce TGF-beta 2. The relevance of this finding was evaluated further by comparing human glioblastoma cells with their nontransformed animal counterpart, astrocytes, with regard to the production of the three TGF-beta isoforms observed so far in mammals. In this report astrocytes are demonstrated to secrete also TGF-beta 2 and to express TGF-beta 1, -beta 2, and -beta 3 mRNA in vitro. In contrast, cultured murine brain macrophages release TGF-beta 1 and are positive for TGF-beta 1 mRNA only. Glia cell-derived TGF-beta 1 and -beta 2 are detected in latent form whereas both latent and active TGF-beta are identified in the supernatant of three human glioblastoma cell lines tested. These cell lines, however, show heterogeneity in regard to the isoform of TGF-beta expressed but share with astrocytes the inability ...
Interneurons are critical for proper neural network function and can activate Ca2+ signaling in astrocytes. However, the impact of the interneuron-astrocyte signaling into neuronal network operation remains unknown. Using the simplest hippocampal Astrocyte-Neuron network, i.e., GABAergic interneuron, pyramidal neuron, single CA3-CA1 glutamatergic synapse, and astrocytes, we found that interneuron-astrocyte signaling dynamically affected excitatory neurotransmission in an activity- and time-dependent manner, and determined the sign (inhibition vs potentiation) of the GABA-mediated effects. While synaptic inhibition was mediated by GABAA receptors, potentiation involved astrocyte GABAB receptors, astrocytic glutamate release, and presynaptic metabotropic glutamate receptors. Using conditional astrocyte-specific GABAB receptor (Gabbr1) knockout mice, we confirmed the glial source of the interneuron-induced potentiation, and demonstrated the involvement of astrocytes in hippocampal theta and gamma ...
Neuroinflammation is an essential defense response to pathogens or injury in the central nervous system, but might also contribute to the pathogenesis of neurological disorders. Astrocytes are glial cells that are implicated in neuroinflammation, but also in brain development and homeostasis. The NF-kappa B transcription factors are key regulators of inflammation that also regulate in cell proliferation, differentiation and survival. Previous studies suggested that NF-kappa B activation in astrocytes might indeed be critical for neuroinflammatory responses and its pathological consequences. In the present study a novel mouse model was characterized to further elucidate the role of astroglial NF-Kappa B signaling in neuroinflammation. This model conditionally expresses a constitutively active mutant of the NF-kappa B activating kinase IKK2 in astrocytes. This results in astroglial NF-kappa B activation, which is sufficient to induce a prominent neuroinflammatory response and impairs brain ...
Neuroinflammation is an essential defense response to pathogens or injury in the central nervous system, but might also contribute to the pathogenesis of neurological disorders. Astrocytes are glial cells that are implicated in neuroinflammation, but also in brain development and homeostasis. The NF-kappa B transcription factors are key regulators of inflammation that also regulate in cell proliferation, differentiation and survival. Previous studies suggested that NF-kappa B activation in astrocytes might indeed be critical for neuroinflammatory responses and its pathological consequences. In the present study a novel mouse model was characterized to further elucidate the role of astroglial NF-Kappa B signaling in neuroinflammation. This model conditionally expresses a constitutively active mutant of the NF-kappa B activating kinase IKK2 in astrocytes. This results in astroglial NF-kappa B activation, which is sufficient to induce a prominent neuroinflammatory response and impairs brain ...
Supplementary MaterialsSupplementary Information 41467_2020_14466_MOESM1_ESM. following faraway cortical brain injury in mice. Fibrinogen inhibited neuronal differentiation in SVZ and hippocampal NSPCs while promoting astrogenesis via activation of the BMP receptor signaling pathway. Pharmacologic and Genetic depletion of fibrinogen reduced astrocyte formation within the SVZ after cortical injury, reducing the contribution of NVP-2 SVZ-derived reactive astrocytes to lesion scar tissue formation. We suggest that fibrinogen can be a regulator of NVP-2 NSPC-derived astrogenesis through the SVZ market via BMP receptor signaling pathway pursuing damage. transgenic reporter mice in conjunction with pharmacologic fibrinogen depletion exposed decreased contribution NVP-2 of SVZ-derived Thbs4?+?reactive astrocytes to lesion scar formation. Appropriately, fibrinogen inhibited neuronal differentiation of NVP-2 major NSPCs through the SVZ or hippocampus and advertised their differentiation into astrocytes ...
Aspirin has been used as anti-inflammatory and anti-aggregate for decades but the precise mechanism(s) of action after the presence of the toxic peptide Aβ1-42 in cultured astrocytes remains poorly resolved. Here we use low-doses of aspirin (10-7 M) in astrocytes in primary culture in presence or absence of Aβ1-42 toxic peptide. We noted an increase of cell viability and proliferation with or without Aβ1-42 peptide presence in aspirin treated cells. In addition, a decrease in apoptosis, determined by Caspase 3 activity and the expression of Cyt c and Smac/Diablo, were detected. Also, aspirin diminished necrosis process (LDH levels), pro-inflammatory mediators (IL-β and TNF-α) and NF-ᴋB protein expression, increasing anti-inflammatory PPAR-γ protein expression, preventing Aβ1-42 toxic effects. Aspirin inhibited COX-2 and iNOS without changes in COX-1 expression, increasing anti-oxidant protein (Cu/Zn-SOD and Mn-SOD) expression in presence or absence of Aβ1-42. Taken together, our ...
The energy requirements of the brain are very high, and tight regulatory mechanisms operate to ensure adequate spatial and temporal delivery of energy substrates in register with neuronal activity. Astrocytes a type of glial cell have emerged as active players in brain energy delivery, production, utilization, and storage. Our understanding of neuroenergetics is rapidly evolving from a neurocentric view to a more integrated picture involving an intense cooperativity between astrocytes and neurons. This review focuses on the cellular aspects of brain energy metabolism, with a particular emphasis on the metabolic interactions between neurons and astrocytes.. Keywords: Nuclear-Magnetic-Resonance ; Cerebral-Blood-Flow ; Vasoactive Intestinal Polypeptide ; Lactate-Shuttle Hypothesis ; Human Visual-Cortex ; Rat-Brain ; Glucose-Utilization ; Nitric-Oxide ; In-Vivo ; Oxidative-Metabolism. ...
The release of transmitters from glia influences synaptic functions. The modalities and physiological functions of glial release are poorly understood. Here we show that glutamate exocytosis from astrocytes of the rat hippocampal dentate molecular layer enhances synaptic strength at excitatory synap …
Endoplasmic reticulum (ER) stress is a common feature of Parkinsons disease (PD), and several PD-related genes are responsible for ER dysfunction. Recent studies suggested LRRK2-G2019S, a pathogenic mutation in the PD-associated gene LRRK2, cause ER dysfunction, and could thereby contribute to the development of PD. It remains unclear, however, how mutant LRRK2 influence ER stress to control cellular outcome. In this study, we identified the mechanism by which LRRK2-G2019S accelerates ER stress and cell death in astrocytes. To investigate changes in ER stress response genes, we treated LRRK2-wild type and LRRK2-G2019S astrocytes with tunicamycin, an ER stress-inducing agent, and performed gene expression profiling with microarrays. The XBP1 SUMOylation and PIAS1 ubiquitination were performed using immunoprecipitation assay. The effect of astrocyte to neuronal survival were assessed by astrocytes-neuron coculture and slice culture systems. To provide in vivo proof-of-concept of our approach, we measured
Figure 1. Live imaging of neuronal differentiation. Ravin, et al, used SBIs Human Nestin pGreenFire Differentiation Reporter (Cat.# SR10016VA-1), which drives GFP expression from the glial fibrillary acidic protein promoter, to watch human neural stem cells differentiate into a network of mature neurons, oligodendrocytes, and astrocytes over the course of seven days. The periodic flashes seen in this video correspond to fluorescent photos taken of the growing cells to identify the GFP signals. The final photo taken after the network formation is shown below the video (color added). Among the network of neurons, only the astrocytes are bright green, demonstrating the specificity of SBIs human Nestin pGreenFire Differentiation Reporter.. ...
Support Cells. Neurons in the CNS are outnumbered by support cells, including macroglia, microglia, vascular elements, the cerebrospinal fluid (CSF)-forming cells of the choroid plexus found within the intracerebral ventricular system, and the meninges, which cover the surface of the brain and comprise the CSF-containing envelope. Macroglia are the most abundant support cells; some are categorized as astrocytes (cells interposed between the vasculature and the neurons, often surrounding individual compartments of synaptic complexes). Astrocytes play a variety of metabolic support roles including furnishing energy intermediates and supplementary removal of neurotransmitters following release. The oligodendroglia, a second prominent category of macroglia, are myelin-producing cells. Myelin, made up of multiple layers of compacted membranes, insulate segments of axons bioelectrically and permit nondecremental propagation of action potentials. Microglia are derived from mesoderm and are related to ...