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Human NT2/D1 cells differentiate into functional astrocytes.

As the most numerous cell type in the brain, astrocytes are coupled via gap junction channels. It is believed that communication among astrocytes is normally regulated by extracellular ions, neurotransmitters and neuromodulators. However, the level of astrocytic coupling is altered in abnormal conditions such as stroke, brain trauma and Alzheimer's disease. A well established human progenitor cell line, NT2/D1, has been previously differentiated into pure neuronal cultures. In the current study, for the first time, we report the differentiation of NT2/D1 cells into astrocytes, which express co…

Demonstration of ganglioside GD3 in human reactive astrocytes.

Astrocytes are the cells that actively participate in the process of lesion repair in the central nervous system (CNS), and reactive astrocytosis of varying degrees becomes apparent with time in any pathological condition occurring in the normally developed postnatal CNS. Ganglioside GD3 (II3a(NeuAca2-8NeuAc)-LacCer, GD3) in reactive astrocytes from autopsied patients with Creutzfeldt-Jakob disease (CJD) and old cerebral infarction was investigated immunocytochemically, using mouse IgM anti-GD3 monoclonal antibody (DSG-1). Reactive astrocytes in CJD and cerebral infarction demonstrated GD3-imm…

HSP70 protects murine astrocytes from glucose deprivation injury.

Expression of the 70 kDa heat shock protein (HSP70) induced by a first insult is associated with protection from a subsequent ischemic insult in brain. Expression of the human inducible HSP70 was previously shown to protect astrocytes in primary culture from combined oxygen-glucose deprivation. These studies have now been extended to demonstrate that HSP70 expression also protects from isolated glucose deprivation. Slight protection was seen against hydrogen peroxide (H2O2) exposure. Glutathione levels decrease less after glucose deprivation or H2O2 exposure (200 microM) in the cells overexpre…

Gene expression in astrocytes during and after ischemia.

Involvement of the IEGs in brain injury and ischemia is under intensive investigation (Gubits et al., 1993). There are several families of t … 87; Sheng and Greenberg, 1990). It is likely that the c-fos gene up-regulation observed in ischemic astrocytes leads to the changes observed in the expressions of hsp and cytoskeleton protein genes in this experimental model. This is supported by the findings of Sarid (1991) and Pennypacker et al. (1994) who have shown that AP-1 DNA binding activity in hippo …

Ionic dependence of adenosine uptake into cultured astrocytes.

Adenosine uptake in cultured astrocytes is dependent on various ions and energy metabolism. The Na(+)-gradient plays an important role, since nigericin, ouabain, amiloride and substitution of Na+ with choline inhibited adenosine uptake. The proton-gradient was of importance, since carbonylcyanide m-chlorophenylhydrozone (CCCP) and omeprazole also inhibited adenosine uptake. Furthermore, adenosine uptake was dependent on Cl- anion. Substitution of Cl- with isethionate, as well as DIDS or furosemide inhibited adenosine uptake. Adenosine uptake was also sensitive to Ca2+ gradient, removal of extr…

Volume-activated Rb+ transport in astrocytes in culture.

The involvement of K+ on the volume regulatory process in astrocytes was investigated by characterizing the hyposmolarity-induced efflux of K+ using 86Rb as a tracer. About 70 and 30% of the intracellular content of 86Rb was released after reductions in osmolarity from 320 to 160 or 220 mosM, respectively, during the time in which cells exhibit a volume regulatory response subsequent to swelling. No significant increase in 86Rb efflux was observed with lower reductions in osmolarity. The 86Rb efflux was Ca2+ independent and insensitive to temperature. It was inhibited by furosemide but not by …

Astrocytes are target cells for endothelins and sarafotoxin.

Endothelin-1, endothelin-3, and the snake venom toxin sarafotoxin S6b stimulate the hydrolysis of phosphatidylinositol by phospholipase C with similar potencies in primary cultures of astrocytes prepared from rat brain cortex. In indo 1-loaded cells, endothelin-1, endothelin-2, endothelin-3, and sarafotoxin induce the rapid mobilization of intracellular Ca2+ stores and promote a more slowly developing influx of Ca2+. These responses were insensitive to pertussis toxin and to inhibitors of cyclooxygenase and lipoxygenase. Similar actions of endothelins and sarafotoxin were observed using astroc…

Заражены ли астроциты прогрессивной многофукальной лейкоэнцефалопатией?

У астроцитов были продемонстрированы ультраструктурные характеристики ранних этапов заражения вирусами PML, т.е. адсорбция, проникновение и внутриклеточный перенос вируса. Эти явления чаще наблюдались в цитоплазме, чем в ядре вируса. Инфекция астроцитов обычно непродуктивна. Легкий и электрон-микроскопический анализ настоящего дела и 23 случая, опубликованных в литературе с 1970 года, позволяют сделать вывод о том, что связь между появлением гигантских причудливых астроцитов и продуктивной инфекцией нетрансформированного астроцита является противоположной. Преобразование астроцитов, похоже, вы

Совпадение в аннотации оригинала
Ultrastructural characteristics of the early steps of PML virus infection, i.e. adsorption, penetration, and intracellular virus transport were demonstrated in astrocytes. These phenomena were more frequently seen in the cytoplasm than virus assembly in the nuclei. Infection of the astrocytes is usually non-productive. Light- and electron-microscopic analysi…

HIV-1 Nef induces astrocytes proliferation, inflammatory response, A1-like astrocytes polarization and subsequent neuronal apoptosis via NF-κB signaling pathway.

Currently, human immunodeficiency virus-1 (HIV-1) spreads around the globe and half of HIV-1-positive individuals suffer from HIV-associated neurocognitive disorder (HAND). HIV-1 infection of astrocytes leads to neuroinflammation and neuronal injury. However, the underlying molecular mechanisms of HIV-1 negative factor (Nef)-mediated astrocytic dysfunction, remain largely unclear. In the present study, our data showed that astrocytic Nef expression facilitated astrocytes proliferation, pro-inflammatory cytokines production and A1-like astrocytes polarization. Mechanistically, Nef-activated NF-…

Dual strategies for neural injury repair: Targeted modulation of reactive astrocytes and functional astrocyte transplantation.

Reactive astrogliosis-the adaptive structural and functional remodeling responses of astrocytes-is a biphasic response to neural injury. While initially protective, it often transitions into a chronic, detrimental state characterized by sustained neuroinflammation, blood-brain barrier disruption, and excitotoxicity, which collectively impede recovery. To address this, this review systematically compares the responses of reactive astrocytes across three major neural pathologies-traumatic brain injury, ischemic stroke, and spinal cord injury-identifying both conserved molecular targets that are …

Factors determining the morphology and distribution of astrocytes in the cat retina: a 'contact-spacing' model of astrocyte interaction.

The retina provides a valuable opportunity to examine the interaction of astrocytes with neurones and vasculature, in adult tissue and in vivo. We have studied astrocytes in cat retina to delineate the interactions that determine their morphology and distribution. Their morphology varied with their interaction with surrounding cells, from a classic stellate shape to an elongated bipolar form associated with axon bundles. Evidence is presented that the distribution of astrocytes across the retina is determined by their morphology and by a previously unrecognised interaction between astrocytes, …

Astrocyte heterogeneity within white matter tracts and a unique subpopulation of optic nerve head astrocytes.

Much of what we know about astrocyte form and function is derived from the study of gray matter protoplasmic astrocytes, whereas white matter fibrous astrocytes remain relatively unexplored. Here, we used the ribotag approach to isolate ribosome-associated mRNA and investigated the transcriptome of uninjured fibrous astrocytes from three regions: unmyelinated optic nerve head, myelinated optic nerve proper, and corpus callosum. Astrocytes from each region were transcriptionally distinct and we identified region-specific astrocyte genes and pathways. Energy metabolism, particularly oxidative ph…

Astrocytic GABAB Receptors in Mouse Hippocampus Control Responses to Behavioral Challenges through Astrocytic BDNF.

Major depressive disorder (MDD) is a common mood disorder that affects almost 20% of the global population. In addition, much evidence has i … in MDD, we knocked down GABABRs in the hippocampus and found that knocking down these receptors in astrocytes, but not in GABAergic or pyramidal neurons, caused a decrease in immobility in the forced swimming test (FST) without affecting other anxiety- and depression-related behaviors. We also generated astrocyte-specific GABABR-knockout mice and found decr …

Upregulation of EphA4 on astrocytes potentially mediates astrocytic gliosis after cortical lesion in the marmoset monkey.

Glial scar formation occurs in response to brain injury in mammalian models and inhibits axonal growth. Identification of molecules that may mediate reactivity of astrocytes has become a leading therapeutic goal in the field of neurotrauma. In adult rodent brain and spinal cord, many of the Eph receptors and their ephrin ligands have been demonstrated to be upregulated on reactive astrocytes at the injury site; however, little is known about the expression of these molecules in nonhuman primate injury models. This study examines the role of the tyrosine kinase EphA4 receptor, which predominant…

Autophagy-Lysosomal Axis Stimulation by Beta-Hydroxybutyrate in Astrocytes.

Beta-hydroxybutyrate (D-BHB), a ketone body with neuroprotective properties, has been previously shown to increase the autophagic flux in neurons, but its effect on autophagy induction in astrocytes remains unexplored. Astrocyte functionality is essential for neuronal support, and this includes an optimal degradation and recycling of organelles and other cellular components through autophagy. The present study shows that D-BHB exposure to cultured astrocytes elevates the conjugated form of microtubule-associated protein 1A/1B-light chain 3 (LC3-II) levels, increases the number of autophagosome…

Varicose projection astrocytes: Conserved reactive cells in brain pathology.

Astrocytes play essential roles in neuropathology. Human astrocytes exhibit unique properties, highlighting the importance of studying astrocytic responses in human models. Varicose projection astrocytes, previously considered exclusive to hominoids and a physiological type of astrocytes, were suggested to reflect pathological burden, albeit direct evidence linking them to neurological diseases has been lacking. Here, we demonstrate that varicose projection astrocytes also appear in other mammals and show, from four distinct human-based disease models, that varicose projection astrocytes are i…

Astrocytes in Genetic Epilepsies: Supporting Actor or Key Player?

Epilepsy is one of the most common neurological disorders worldwide, affecting around 1% of the population. The epilepsies represent a diver … also a common feature of neurodevelopmental disorders such as Fragile X syndrome and Rett syndrome. Astrocytes, the most numerous glial cells in the central nervous system, have emerged as crucial players in the pathophysiology of acquired epilepsies. Whilst the contribution of astrocytes to acquired epilepsy has been widely reviewed, astrocyte dysfunction i …

Astrocytes: Orchestrators of brain gas exchange and oxygen homeostasis.

If we consider neurons like muscles during exercise, the demand for oxygen (O2) and carbon dioxide (CO2) elimination is constantly changing. This review summarises the evidence that astrocytes are essential for homeostasis of the respiratory gases in the brain, with a particular focus on oxygen homeostasis. Astrocytes surround cerebral blood vessels and sense changes in oxygen availability in the milieu. They contribute to pH homeostasis and are increasingly recognized for their contribution to central chemosensitivity, particularly in detecting changes in CO2 and proton (H+) concentrations. T…

Role of astrocytes connexins - pannexins in acute brain injury.

Acute brain injuries (ABIs) encompass a broad spectrum of primary injuries such as ischemia, hypoxia, trauma, and hemorrhage that converge into secondary injury where some mechanisms show common determinants. In this regard, astroglial connexin and pannexin channels have been shown to play an important role. These channels are transmembrane proteins sharing similar topology and form gateways between adjacent cells named gap junctions (GJs) and pores into unopposed membranes named hemichannels (HCs). In astrocytes, GJs and HCs enable intercellular communication and have active participation in …