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SARS-CoV-2 spike triggers TLR7-dependent endolysosome dysfunction and senescence in human astrocytes.

SARS-CoV-2 infection is associated with long-lasting neuropsychiatric and cognitive symptoms, collectively referred to as neuro-PASC. Emerging studies indicates that accelerate brain aging and cellular senescence in COVID brain could lead to altered neuroimmune responses and neurodegenerative outcomes. However, little is known about how cellular senescence is development in neuro-PASC. Here, we examined the role of spike protein subunit S1, a persistent viral antigen, in driving the development of cellular senescence in primary human astrocytes. We have demonstrated that S1 enters endolysosome…

VEGFR-3 deficiency in astrocytes exacerbates Japanese encephalitis virus-induced neuroinflammation in mouse brains.

Japanese encephalitis virus (JEV), a highly neurotropic flavivirus, preferentially targets neurons, where it replicates efficiently and indu … hage-expressed VEGFR-3 suppresses bacterial sepsis and neuroinflammatory responses, its function in astrocytes during viral encephalitis remains unclear. To elucidate the astrocytic role of VEGFR-3 in JEV pathogenesis, mice carrying a conditional deletion of the VEGFR-3 ligand-binding domain specifically in astrocytes were generated. Astrocyte-specific VEGFR …

CLEC16A in astrocytes promotes mitophagy and limits pathology in a multiple sclerosis mouse model.

Astrocytes promote neuroinflammation and neurodegeneration in multiple sclerosis (MS) through cell-intrinsic activities and their ability to recruit and activate other cell types. In a genome-wide CRISPR-based forward genetic screen investigating regulators of astrocyte proinflammatory responses, we identified the C-type lectin domain-containing 16A gene (CLEC16A), linked to MS susceptibility, as a suppressor of nuclear factor-κB (NF-κB) signaling. Gene and small-molecule perturbation studies in mouse primary and human embryonic stem cell-derived astrocytes in combination with multiomic analys…

Astrocytes mediate two forms of spike timing-dependent depression at entorhinal cortex-hippocampal synapses.

The entorhinal cortex (EC) connects to the hippocampus sending different information from cortical areas that is first processed at the dent … TD require postsynaptic calcium, eCB synthesis, CB1R, astrocyte activity, and glutamate released by astrocytes. Thus, we discovered two novel forms of t-LTD that require astrocytes at EC-GC synapses.

Comparative Proteomics Highlights that GenX Exposure Leads to Metabolic Defects and Inflammation in Astrocytes.

Exposure to PFAS such as GenX (HFPO dimer acid) has become increasingly common due to the replacement of older generation PFAS in manufactur … regulating GABA-associated pathways and the immune system, we next explored the effects of GenX on astrocytes, as astrocytes in the brain can regulate GABA. An array of assays demonstrated GenX exposure may lead to mitochondrial dysfunction and neuroinflammatory response in astrocytes, possibly linking non-cell autonomous neurodegeneration to the motor defi …

iPSC-derived healthy human astrocytes selectively load miRNAs targeting neuronal genes into extracellular vesicles.

Astrocytes are in constant communication with neurons during the establishment and maturation of functional networks in the developing brain. Astrocytes release extracellular vesicles (EVs) containing microRNA (miRNA) cargo that regulates transcript stability in recipient cells. Astrocyte released factors are thought to be involved in neurodevelopmental disorders. Healthy astrocytes partially rescue Rett Syndrome (RTT) neuron function. EVs isolated from stem cell progeny also correct aspects of RTT. EVs cross the blood-brain barrier (BBB) and their cargo is found in peripheral blood which may …

Taurine Chloramine-Mediated Nrf2 Activation and HO-1 Induction Confer Protective Effects in Astrocytes.

Taurine is ubiquitously distributed in mammalian tissues, with the highest levels in the brain, heart, and leukocytes. Taurine reacts with hypochlorous acid (HOCl) to produce taurine chloramine (Tau-Cl) via the myeloperoxidase (MPO) system. In this study, we elucidated the antioxidative and protective effects of Tau-Cl in astrocytes. Tau-Cl increased the expression and nuclear translocation of nuclear factor E2-related factor (Nrf2) and the expression of Nrf2-regulated antioxidant genes, including heme oxygenase 1 (HO-1). Nrf2 activity is negatively regulated by Kelch-like ECH-associated prote…

Dysregulation of neuroprotective lipoxin pathway in astrocytes in response to cytokines and ocular hypertension​.

Glaucoma leads to vision loss due to retinal ganglion cell death. Astrocyte reactivity contributes to neurodegeneration. Our recent study found that lipoxin B4 (LXB4), produced by retinal astrocytes, has direct neuroprotective actions on retinal ganglion cells. In this study, we aimed to investigate how the autacoid LXB4 influences astrocyte reactivity in the retina under inflammatory cytokine-induced activation and during ocular hypertension. The protective activity of LXB4 was investigated in vivo using the mouse silicone-oil model of chronic ocular hypertension. By employing a range of anal…

Preconditioning-Induced Facilitation of Lactate Release from Astrocytes Is Essential for Brain Ischemic Tolerance.

A sublethal ischemic episode [termed preconditioning (PC)] protects neurons in the brain against a subsequent severe ischemic injury. This phenomenon is known as brain ischemic tolerance and has received much attention from researchers because of its robust neuroprotective effects. We have previously reported that PC activates astrocytes and subsequently upregulates P2X7 receptors, thereby leading to ischemic tolerance. However, the downstream signals of P2X7 receptors that are responsible for PC-induced ischemic tolerance remain unknown. Here, we show that PC-induced P2X7 receptor-mediated la…

Гетерогенный Ribonucleoprotein K — нормативный фактор реконструкции вируса Чикунгунья в астроцитах.

Вирус Чикунгунья (CHIKV) все чаще ассоциируется с тяжелыми неврологическими последствиями и долгосрочной заболеваемостью. Вместе с тем, в центре нервной системы (ЦНС) существует ограниченное понимание важнейших компонентов хост-комплексного комплекса CHIKV, а следовательно, и факторов репликации и вирулентности. Кроме того, в большинстве исследований CHIKV CNS основное внимание уделяется нейронной инфекции, несмотря на то, что астроциты представляют собой основную цель в области мозга. Гетерогенный рибуклеопротеин K (hnRNP K), имеющий обязательную силу для РНК белок, связанный с скрещиванием,

Совпадение в аннотации оригинала
Chikungunya virus (CHIKV) is an emerging, mosquito-borne arthritic alphavirus increasingly associated with severe neurological sequelae and … stem (CNS). Furthermore, the majority of CHIKV CNS studies focus on neuronal infection, even though astrocytes represent the main cerebral target. Heterogeneous ribonucleoprotein K (hnRNP K), an RNA-binding protein involved in RNA splicing, trafficking, and translation, is a regulatory component of alphavirus replicase assembly complexes, but has yet to be t …

Human Immunodeficiency Virus (HIV-1) Targets Astrocytes via Cell-Free and Cell-Associated Infection.

BACKGROUND: Infection of astrocytes by Human Immunodeficiency Virus (HIV-1) remains a topic of debate, with conflicting data, yet instances of astrocytes containing viral DNA have been observed in vivo. In this study, we aimed to elucidate potential routes through which astrocytes could be infected and their ability to produce infectious particles using primary human astrocytes. METHODS: We infected primary astrocytes derived from either neuroprogenitor cells (NPCs) or induced pluripotent stem cells (iPSCs) that express both C-X-C chemokine receptor type 4 (CXCR4) and the C-C chemokine recept…

Disease-associated astrocytes and microglia markers are upregulated in mice fed high fat diet.

High-fat diet (HFD) is associated with Alzheimer's disease (AD) and type 2 diabetes risk, which share features such as insulin resistance and amylin deposition. We examined gene expression associated with astrocytes and microglia since dysfunction of these cell types is implicated in AD pathogenesis. We hypothesize gene expression changes in disease-associated astrocytes (DAA), disease-associated microglia and human Alzheimer's microglia exist in diabetic and obese individuals before AD development. By analyzing bulk RNA-sequencing (RNA-seq) data generated from brains of mice fed HFD and human…

ApoE4-dependent lysosomal cholesterol accumulation impairs mitochondrial homeostasis and oxidative phosphorylation in human astrocytes.

Recent developments in genome sequencing have expanded the knowledge of genetic factors associated with late-onset Alzheimer's disease (AD). Among them, genetic variant ε4 of the APOE gene (APOE4) confers the greatest disease risk. Dysregulated glucose metabolism is an early pathological feature of AD. Using isogenic ApoE3 and ApoE4 astrocytes derived from human induced pluripotent stem cells, we find that ApoE4 increases glycolytic activity but impairs mitochondrial respiration in astrocytes. Ultrastructural and autophagy flux analyses show that ApoE4-induced cholesterol accumulation impairs …

Dysregulation of Neuroprotective Lipoxin Pathway in Astrocytes in Response to Cytokines and Ocular Hypertension.

Glaucoma leads to vision loss due to retinal ganglion cell death. Astrocyte reactivity contributes to neurodegeneration. Our recent study found that lipoxin B4 (LXB4), produced by retinal astrocytes, has direct neuroprotective actions on retinal ganglion cells. In this study, we aimed to investigate how the autacoid LXB4 influences astrocyte activity in the retina under inflammatory cytokine-induced activation and during ocular hypertension. The protective activity of LXB4 was investigated in vivo using the mouse silicone-oil model of chronic ocular hypertension (n=40). By employing a range of…

Rift Valley fever virus modulates apoptosis and immune response during infection of human astrocytes.

Rift Valley fever (RVF) is an arboviral disease of zoonotic origin that causes recurrent epidemics in Africa, the Arabic Peninsula, and islands of the South West of the Indian Ocean. RVF occurs mainly in livestock but also affects humans with severe clinical manifestations, including neurological disorders. However, human neuropathogenesis of Rift Valley fever virus (RVFV) is still poorly characterized. To study the interactions between RVFV and the central nervous system (CNS), we focused on RVFV infection of astrocytes, the major glial cells of the CNS that have several supporting roles incl…

Astrocytes evoke a robust IRF7-independent type I interferon response upon neurotropic viral infection.

BACKGROUND: Type I interferons (IFN-I) are fundamental in controlling viral infections but fatal interferonopathy is restricted in the immun … on. An increased viral replication in IRF7-deficient mice suggests an indirect antiviral mechanism. Astrocytes rely on IRF7 to establish a cell-autonomous antiviral response. Notably, the loss of IRF7 particularly in astrocytes resulted in a high IFN-I production. Sustained production of IFN-I in astrocytes is independent of an IRF7-mediated positive feedbac …

Role of Microglia and Astrocytes in Alzheimer's Disease: From Neuroinflammation to Ca2+ Homeostasis Dysregulation.

Alzheimer's disease (AD) is the most common form of dementia worldwide, with a complex, poorly understood pathogenesis. Cerebral atrophy, am … ation-related inflammatory processes, scant data are available on its contribution in microglia and astrocytes functioning, both in health and throughout the AD continuum. Nevertheless, AD-related aberrant Ca2+ signalling in astrocytes and microglia is crucially involved in the mechanisms underpinning neuroinflammatory processes that, in turn, impact neurona …

Adiponectin Promotes Neurogenesis After Transient Cerebral Ischemia Through STAT3 Mediated BDNF Upregulation in Astrocytes.

Newborn neurons from the subventricular zone (SVZ) are essential to functional recovery following ischemic stroke. However, the number of ne … ological recovery. Mechanistically, adiponectin increased the protein levels of p-STAT3 and BDNF in astrocytes on day 7 of reperfusion, while silencing BDNF diminished the adiponectin-induced neurogenesis and functional recovery. Moreover, inhibition of STAT3 not only prevented the increase of BDNF but also the improved neurogenesis and functional recovery a …

Isolation and characterization of neurotoxic astrocytes derived from adult triple transgenic Alzheimer's disease mice.

Alzheimer's disease has been considered mostly as a neuronal pathology, although increasing evidence suggests that glial cells might play a key role in the disease onset and progression. In this sense, astrocytes, with their central role in neuronal metabolism and function, are of great interest for increasing our understanding of the disease. Thus, exploring the morphological and functional changes suffered by astrocytes along the course of this disorder has great therapeutic and diagnostic potential. In this work we isolated and cultivated astrocytes from symptomatic 9-10-months-old adult 3x…