In the mammalian central nervous system(CNS),astrocytes are the ubiquitous glial cells that have complex morphological and molecular characteristics.These fascinating cells play essential neurosupportive and homeostat...In the mammalian central nervous system(CNS),astrocytes are the ubiquitous glial cells that have complex morphological and molecular characteristics.These fascinating cells play essential neurosupportive and homeostatic roles in the healthy CNS and undergo morphological,molecular,and functional changes to adopt so-called‘reactive’states in response to CNS injury or disease.In recent years,interest in astrocyte research has increased dramatically and some new biological features and roles of astrocytes in physiological and pathological conditions have been discovered thanks to technological advances.Here,we will review and discuss the wellestablished and emerging astroglial biology and functions,with emphasis on their potential as therapeutic targets for CNS injury,including traumatic and ischemic injury.This review article will highlight the importance of astrocytes in the neuropathological process and repair of CNS injury.展开更多
Neurotoxic astrocytes are a promising therapeutic target for the attenuation of cerebral ischemia/reperfusion injury.Low-density lipoprotein receptor,a classic cholesterol regulatory receptor,has been found to inhibit...Neurotoxic astrocytes are a promising therapeutic target for the attenuation of cerebral ischemia/reperfusion injury.Low-density lipoprotein receptor,a classic cholesterol regulatory receptor,has been found to inhibit NLR family pyrin domain containing protein 3(NLRP3)inflammasome activation in neurons following ischemic stroke and to suppress the activation of microglia and astrocytes in individuals with Alzheimer’s disease.However,little is known about the effects of low-density lipoprotein receptor on astrocytic activation in ischemic stroke.To address this issue in the present study,we examined the mechanisms by which low-density lipoprotein receptor regulates astrocytic polarization in ischemic stroke models.First,we examined low-density lipoprotein receptor expression in astrocytes via immunofluorescence staining and western blotting analysis.We observed significant downregulation of low-density lipoprotein receptor following middle cerebral artery occlusion reperfusion and oxygen-glucose deprivation/reoxygenation.Second,we induced the astrocyte-specific overexpression of low-density lipoprotein receptor using astrocyte-specific adeno-associated virus.Low-density lipoprotein receptor overexpression in astrocytes improved neurological outcomes in middle cerebral artery occlusion mice and reversed neurotoxic astrocytes to create a neuroprotective phenotype.Finally,we found that the overexpression of low-density lipoprotein receptor inhibited NLRP3 inflammasome activation in oxygen-glucose deprivation/reoxygenation injured astrocytes and that the addition of nigericin,an NLRP3 agonist,restored the neurotoxic astrocyte phenotype.These findings suggest that low-density lipoprotein receptor could inhibit the NLRP3-meidiated neurotoxic polarization of astrocytes and that increasing low-density lipoprotein receptor in astrocytes might represent a novel strategy for treating cerebral ischemic stroke.展开更多
Traumatic brain injury is a global health crisis,causing significant death and disability worldwide.Neuroinflammation that follows traumatic brain injury has serious consequences for neuronal survival and cognitive im...Traumatic brain injury is a global health crisis,causing significant death and disability worldwide.Neuroinflammation that follows traumatic brain injury has serious consequences for neuronal survival and cognitive impairments,with astrocytes involved in this response.Following traumatic brain injury,astrocytes rapidly become reactive,and astrogliosis propagates from the injury core to distant brain regions.Homeostatic astroglial proteins are downregulated near the traumatic brain injury core,while pro-inflammatory astroglial genes are overexpressed.This altered gene expression is considered a pathological remodeling of astrocytes that produces serious consequences for neuronal survival and cognitive recovery.In addition,glial scar formed by reactive astrocytes is initially necessary to limit immune cell infiltration,but in the long term impedes axonal reconnection and functional recovery.Current therapeutic strategies for traumatic brain injury are focused on preventing acute complications.Statins,cannabinoids,progesterone,beta-blockers,and cerebrolysin demonstrate neuroprotective benefits but most of them have not been studied in the context of astrocytes.In this review,we discuss the cell signaling pathways activated in reactive astrocytes following traumatic brain injury and we discuss some of the potential new strategies aimed to modulate astroglial responses in traumatic brain injury,especially using cell-targeted strategies with miRNAs or lncRNA,viral vectors,and repurposed drugs.展开更多
Astrocytes are the most abundant type of glial cell in the central nervous system.Upon injury and inflammation,astrocytes become reactive and undergo morphological and functional changes.Depending on their phenotypic ...Astrocytes are the most abundant type of glial cell in the central nervous system.Upon injury and inflammation,astrocytes become reactive and undergo morphological and functional changes.Depending on their phenotypic classification as A1 or A2,reactive astrocytes contribute to both neurotoxic and neuroprotective responses,respectively.However,this binary classification does not fully capture the diversity of astrocyte responses observed across different diseases and injuries.Transcriptomic analysis has revealed that reactive astrocytes have a complex landscape of gene expression profiles,which emphasizes the heterogeneous nature of their reactivity.Astrocytes actively participate in regulating central nervous system inflammation by interacting with microglia and other cell types,releasing cytokines,and influencing the immune response.The phosphoinositide 3-kinase(PI3K)/protein kinase B(AKT)signaling pathway is a central player in astrocyte reactivity and impacts various aspects of astrocyte behavior,as evidenced by in silico,in vitro,and in vivo results.In astrocytes,inflammatory cues trigger a cascade of molecular events,where nuclear factor-κB serves as a central mediator of the pro-inflammatory responses.Here,we review the heterogeneity of reactive astrocytes and the molecular mechanisms underlying their activation.We highlight the involvement of various signaling pathways that regulate astrocyte reactivity,including the PI3K/AKT/mammalian target of rapamycin(mTOR),αvβ3 integrin/PI3K/AKT/connexin 43,and Notch/PI3K/AKT pathways.While targeting the inactivation of the PI3K/AKT cellular signaling pathway to control reactive astrocytes and prevent central nervous system damage,evidence suggests that activating this pathway could also yield beneficial outcomes.This dual function of the PI3K/AKT pathway underscores its complexity in astrocyte reactivity and brain function modulation.The review emphasizes the importance of employing astrocyte-exclusive models to understand their functions accurately and these models are essential for clarifying astrocyte behavior.The findings should then be validated using in vivo models to ensure real-life relevance.The review also highlights the significance of PI3K/AKT pathway modulation in preventing central nervous system damage,although further studies are required to fully comprehend its role due to varying factors such as different cell types,astrocyte responses to inflammation,and disease contexts.Specific strategies are clearly necessary to address these variables effectively.展开更多
Astrocytes are functionally dynamic cells that support neurons in multiple ways throughout an organism’s lifespan.The astrocytic regulation of neuronal activity has been increasingly recognized in recent years.Astroc...Astrocytes are functionally dynamic cells that support neurons in multiple ways throughout an organism’s lifespan.The astrocytic regulation of neuronal activity has been increasingly recognized in recent years.Astrocytes are now recognized as playing a more complex role than mere bystanders in the central nervous system.However,their role in regulating the sleep neurocircuitry is not well understood.From this perspective,we highlight the role of astrocytes in sleep modulation,with a particular focus on regulatory mechanisms related to the ventrolateral preoptic nucleus(VLPO)of the hypothalamus.We briefly discuss recent literature reporting the role of VLPO astrocytes in regulating sleep-associated behaviors.展开更多
The conventional perception of astrocytes as mere supportive cells within the brain has recently been called into question by empirical evidence, which has revealed their active involvement in regulating brain functio...The conventional perception of astrocytes as mere supportive cells within the brain has recently been called into question by empirical evidence, which has revealed their active involvement in regulating brain function and encoding behaviors associated with emotions.Specifically, astrocytes in the basolateral amygdala have been found to play a role in the modulation of anxiety-like behaviors triggered by chronic stress. Nevertheless, the precise molecular mechanisms by which basolateral amygdala astrocytes regulate chronic stress–induced anxiety-like behaviors remain to be fully elucidated. In this study, we found that in a mouse model of anxiety triggered by unpredictable chronic mild stress, the expression of excitatory amino acid transporter 2 was upregulated in the basolateral amygdala. Interestingly, our findings indicate that the targeted knockdown of excitatory amino acid transporter 2 specifically within the basolateral amygdala astrocytes was able to rescue the anxiety-like behavior in mice subjected to stress. Furthermore, we found that the overexpression of excitatory amino acid transporter 2 in the basolateral amygdala, whether achieved through intracranial administration of excitatory amino acid transporter 2agonists or through injection of excitatory amino acid transporter 2-overexpressing viruses with GfaABC1D promoters, evoked anxiety-like behavior in mice. Our single-nucleus RNA sequencing analysis further confirmed that chronic stress induced an upregulation of excitatory amino acid transporter 2 specifically in astrocytes in the basolateral amygdala. Moreover, through in vivo calcium signal recordings, we found that the frequency of calcium activity in the basolateral amygdala of mice subjected to chronic stress was higher compared with normal mice.After knocking down the expression of excitatory amino acid transporter 2 in the basolateral amygdala, the frequency of calcium activity was not significantly increased, and anxiety-like behavior was obviously mitigated. Additionally, administration of an excitatory amino acid transporter 2 inhibitor in the basolateral amygdala yielded a notable reduction in anxiety level among mice subjected to stress. These results suggest that basolateral amygdala astrocytic excitatory amino acid transporter 2 plays a role in in the regulation of unpredictable chronic mild stress-induced anxiety-like behavior by impacting the activity of local glutamatergic neurons, and targeting excitatory amino acid transporter 2 in the basolateral amygdala holds therapeutic promise for addressing anxiety disorders.展开更多
Invasive inflammation and excessive scar formation are the main reasons for the difficulty in repairing nervous tissue after spinal cord injury.Microglia and astrocytes play key roles in the spinal cord injury micro-e...Invasive inflammation and excessive scar formation are the main reasons for the difficulty in repairing nervous tissue after spinal cord injury.Microglia and astrocytes play key roles in the spinal cord injury micro-environment and share a close interaction.However,the mechanisms involved remain unclear.In this study,we found that after spinal cord injury,resting microglia(M0)were polarized into pro-inflammatory phenotypes(MG1 and MG3),while resting astrocytes were polarized into reactive and scar-forming phenotypes.The expression of growth arrest-specific 6(Gas6)and its receptor Axl were significantly down-regulated in microglia and astrocytes after spinal cord injury.In vitro experiments showed that Gas6 had negative effects on the polarization of reactive astrocytes and pro-inflammatory microglia,and even inhibited the cross-regulation between them.We further demonstrated that Gas6 can inhibit the polarization of reactive astrocytes by suppressing the activation of the Yes-associated protein signaling pathway.This,in turn,inhibited the polarization of pro-inflammatory microglia by suppressing the activation of the nuclear factor-κB/p65 and Janus kinase/signal transducer and activator of transcription signaling pathways.In vivo experiments showed that Gas6 inhibited the polarization of pro-inflammatory microglia and reactive astrocytes in the injured spinal cord,thereby promoting tissue repair and motor function recovery.Overall,Gas6 may play a role in the treatment of spinal cord injury.It can inhibit the inflammatory pathway of microglia and polarization of astrocytes,attenuate the interaction between microglia and astrocytes in the inflammatory microenvironment,and thereby alleviate local inflammation and reduce scar formation in the spinal cord.展开更多
Cerebral edema caused by blood-brain barrier injury after intracerebral hemorrhage is an important factor leading to poor prognosis.Human-induced pluripotent stem cell-derived neural stem cell exosomes(hiPSC-NSC-Exos)...Cerebral edema caused by blood-brain barrier injury after intracerebral hemorrhage is an important factor leading to poor prognosis.Human-induced pluripotent stem cell-derived neural stem cell exosomes(hiPSC-NSC-Exos)have shown potential for brain injury repair in central nervous system diseases.In this study,we explored the impact of hiPSC-NSC-Exos on blood-brain barrier preservation and the underlying mechanism.Our results indicated that intranasal delivery of hiPSC-NSC-Exos mitigated neurological deficits,enhanced blood-brain barrier integrity,and reduced leukocyte infiltration in a mouse model of intracerebral hemorrhage.Additionally,hiPSC-NSC-Exos decreased immune cell infiltration,activated astrocytes,and decreased the secretion of inflammatory cytokines like monocyte chemoattractant protein-1,macrophage inflammatory protein-1α,and tumor necrosis factor-αpost-intracerebral hemorrhage,thereby improving the inflammatory microenvironment.RNA sequencing indicated that hiPSC-NSC-Exo activated the PI3K/AKT signaling pathway in astrocytes and decreased monocyte chemoattractant protein-1 secretion,thereby improving blood-brain barrier integrity.Treatment with the PI3K/AKT inhibitor LY294002 or the monocyte chemoattractant protein-1 neutralizing agent C1142 abolished these effects.In summary,our findings suggest that hiPSC-NSC-Exos maintains blood-brain barrier integrity,in part by downregulating monocyte chemoattractant protein-1 secretion through activation of the PI3K/AKT signaling pathway in astrocytes.展开更多
Stroke is the leading cause of mortality globally,ultimately leading to severe,lifelong neurological impairments.Patients often suffer from a secondary cascade of damage,including neuroinflammation,cytotoxicity,oxidat...Stroke is the leading cause of mortality globally,ultimately leading to severe,lifelong neurological impairments.Patients often suffer from a secondary cascade of damage,including neuroinflammation,cytotoxicity,oxidative stress,and mitochondrial dysfunction.Regrettably,there is a paucity of clinically available therapeutics to address these issues.Emerging evidence underscores the pivotal roles of astrocytes,the most abundant glial cells in the brain,throughout the various stages of ischemic stroke.In this comprehensive review,we initially provide an overview of the fundamental physiological functions of astrocytes in the brain,emphasizing their critical role in modulating neuronal homeostasis,synaptic activity,and blood-brain barrier integrity.We then delve into the growing body of evidence that highlights the functional diversity and heterogeneity of astrocytes in the context of ischemic stroke.Their well-established contributions to energy provision,metabolic regulation,and neurotransmitter homeostasis,as well as their emerging roles in mitochondrial recovery,neuroinflammation regulation,and oxidative stress modulation following ischemic injury,are discussed in detail.We also explore the cellular and molecular mechanisms underpinning these functions,with particular emphasis on recently identified targets within astrocytes that offer promising prospects for therapeutic intervention.In the final section of this review,we offer a detailed overview of the current therapeutic strategies targeting astrocytes in the treatment of ischemic stroke.These astrocyte-targeting strategies are categorized into traditional small-molecule drugs,microRNAs(miRNAs),stem cell-based therapies,cellular reprogramming,hydrogels,and extracellular vesicles.By summarizing the current understanding of astrocyte functions and therapeutic targeting approaches,we aim to highlight the critical roles of astrocytes during and after stroke,particularly in the pathophysiological development in ischemic stroke.We also emphasize promising avenues for novel,astrocyte-targeted therapeutics that could become clinically available options,ultimately improving outcomes for patients with stroke.展开更多
Astrocytes are associated with varying brain size between rodents and primates.As a close evolutionary relative of primates,the tree shrew(Tupaia belangeri)provides a valuable comparative model for investigating glial...Astrocytes are associated with varying brain size between rodents and primates.As a close evolutionary relative of primates,the tree shrew(Tupaia belangeri)provides a valuable comparative model for investigating glial architecture.However,the anatomical distribution and morphological characteristics of astrocytes in the tree shrew brain remain poorly characterized.In this study,glial fibrillary acidic protein(GFAP)immunofluorescence was employed to systematically examine the spatial distribution and morphology of astrocytes in the whole brain of tree shrews.Notably,GFAP-immunoreactive(ir)astrocytes were detected throughout the telencephalon,diencephalon,mesencephalon,metencephalon,and myelencephalon.Distinct laminar distribution was evident in regions such as the main olfactory bulb and hippocampus.Semi-quantitative comparisons revealed significant regional differences in astrocyte density between tree shrews and mice,encompassing the main olfactory bulb,accessory olfactory bulb,olfactory tubercle,cortex,hippocampus,cortical amygdaloid nucleus,hypothalamus,thalamus,superior colliculus,interpeduncular nucleus,median raphe nucleus,and parabrachial nucleus.Compared to mice,tree shrews exhibited higher astrocyte density with increased morphological complexity in the posterior hypothalamic nucleus,dorsomedial hypothalamic nucleus,ventromedial hypothalamic nucleus,and periaqueductal gray,but lower density with greater morphological complexity in the hippocampus and substantia nigra.In the paraventricular hypothalamic nucleus and lateral hypothalamic area,GFAP-ir astrocytes displayed comparable densities between tree shrews and mice but exhibited region-specific differences in morphological complexity.This study provides the first brain-wide mapping of GFAP-ir astrocytes in tree shrews,revealing marked interspecies differences in their distribution and morphology,and establishing a neuroanatomical framework for understanding astrocyte involvement in diverse physiological and behavioral functions.展开更多
Background:The inability of damaged neurons to regenerate and of axons to estab-lish new functional connections leads to permanent functional deficits after spinal cord injury(SCI).Although astrocyte reprogramming hol...Background:The inability of damaged neurons to regenerate and of axons to estab-lish new functional connections leads to permanent functional deficits after spinal cord injury(SCI).Although astrocyte reprogramming holds promise for neurorepair in various disease models,it is not sufficient on its own to achieve significant functional recovery.Methods:A rat SCI model was established using a spinal cord impactor.Seven days postsurgery,adeno-associated virus were injected to overexpress the transcription factors NeuroD1 and Neurogenin-2(Ngn2)in the spinal cord.The rats were then trained to walk on a weight-supported treadmill for 4 weeks,starting 14 days after modeling.The effects of these interventions on motor and sensory functions,as well as spinal cord tissue repair,were subsequently evaluated.Results:The combination of NeuroD1 and Ngn2 overexpression with weight-supported exercise training significantly improved gait compared to either inter-vention alone.The group receiving the combined intervention exhibited enhanced sensitivity in sensory assessments.Immunofluorescence analysis revealed increased colocalization of astrocytes and microtubule-associated protein 2-positive neurons in the injury area.These effects were more pronounced than those observed with spinal cord tissue repair alone.Additionally,the combined intervention significantly reduced glial scarring and the size of the injury area.Conclusion:Exercise intervention enhances the reprogramming effects of astrocytes and restores motor function,yielding better results than either intervention alone.展开更多
Hemorrhagic shock is a common clinical emergency that can aggravate cell injury after resuscitation.Astrocytes are crucial for the survival of neurons because they regulate the surrounding ionic microenvironment of ne...Hemorrhagic shock is a common clinical emergency that can aggravate cell injury after resuscitation.Astrocytes are crucial for the survival of neurons because they regulate the surrounding ionic microenvironment of neurons.Although hemorrhagic shock and resuscitation(HSR)injury can impair cognition,it remains unclear how this insult directly affects astrocytes.In this study,we established an HSR model by bleeding and re-transfusion in mice.The social interaction test and new object recognition test were applied to evaluate post-operative cognitive changes,and the results suggest that mice experience cognitive impairment following exposure to HSR.In the HSR group,the power spectral density ofβandγoscillations decreased,and the coupling of theθoscillation phase andγoscillation amplitude was abnormal,which indicated abnormal neuronal oscillation and cognitive impairment after HSR exposure.In brief,cognitive impairment in mice is strongly correlated with Ca^(2+)signal strength in lateral septum astrocytes following HSR.展开更多
Lactate serves as a key energy metabolite in the central nervous system,facilitating essential brain functions,including energy supply,signaling,and epigenetic modulation.Moreover,it links epigenetic modifications wit...Lactate serves as a key energy metabolite in the central nervous system,facilitating essential brain functions,including energy supply,signaling,and epigenetic modulation.Moreover,it links epigenetic modifications with metabolic reprogramming.Nonetheless,the specific mechanisms and roles of this connection in astrocytes remain unclear.Therefore,this review aims to explore the role and specific mechanisms of lactate in the metabolic reprogramming of astrocytes in the central nervous system.The close relationship between epigenetic modifications and metabolic reprogramming was discussed.Therapeutic strategies for targeting metabolic reprogramming in astrocytes in the central nervous system were also outlined to guide future research in central nervous system diseases.In the nervous system,lactate plays an essential role.However,its mechanism of action as a bridge between metabolic reprogramming and epigenetic modifications in the nervous system requires future investigation.The involvement of lactate in epigenetic modifications is currently a hot research topic,especially in lactylation modification,a key determinant in this process.Lactate also indirectly regulates various epigenetic modifications,such as N6-methyladenosine,acetylation,ubiquitination,and phosphorylation modifications,which are closely linked to several neurological disorders.In addition,exploring the clinical applications and potential therapeutic strategies of lactic acid provides new insights for future neurological disease treatments.展开更多
Epilepsy is a leading cause of disability and mortality worldwide. However, despite the availability of more than 20 antiseizure medications, more than one-third of patients continue to experience seizures. Given the ...Epilepsy is a leading cause of disability and mortality worldwide. However, despite the availability of more than 20 antiseizure medications, more than one-third of patients continue to experience seizures. Given the urgent need to explore new treatment strategies for epilepsy, recent research has highlighted the potential of targeting gliosis, metabolic disturbances, and neural circuit abnormalities as therapeutic strategies. Astrocytes, the largest group of nonneuronal cells in the central nervous system, play several crucial roles in maintaining ionic and energy metabolic homeostasis in neurons, regulating neurotransmitter levels, and modulating synaptic plasticity. This article briefly reviews the critical role of astrocytes in maintaining balance within the central nervous system. Building on previous research, we discuss how astrocyte dysfunction contributes to the onset and progression of epilepsy through four key aspects: the imbalance between excitatory and inhibitory neuronal signaling, dysregulation of metabolic homeostasis in the neuronal microenvironment, neuroinflammation, and the formation of abnormal neural circuits. We summarize relevant basic research conducted over the past 5 years that has focused on modulating astrocytes as a therapeutic approach for epilepsy. We categorize the therapeutic targets proposed by these studies into four areas: restoration of the excitation–inhibition balance, reestablishment of metabolic homeostasis, modulation of immune and inflammatory responses, and reconstruction of abnormal neural circuits. These targets correspond to the pathophysiological mechanisms by which astrocytes contribute to epilepsy. Additionally, we need to consider the potential challenges and limitations of translating these identified therapeutic targets into clinical treatments. These limitations arise from interspecies differences between humans and animal models, as well as the complex comorbidities associated with epilepsy in humans. We also highlight valuable future research directions worth exploring in the treatment of epilepsy and the regulation of astrocytes, such as gene therapy and imaging strategies. The findings presented in this review may help open new therapeutic avenues for patients with drugresistant epilepsy and for those suffering from other central nervous system disorders associated with astrocytic dysfunction.展开更多
Hepatic encephalopathy,defined as neuropsychiatric dysfunction secondary to liver disease,is a frequent decompensating event in cirrhosis.Its clinical impact is highlighted by a notable increase in patient mortality r...Hepatic encephalopathy,defined as neuropsychiatric dysfunction secondary to liver disease,is a frequent decompensating event in cirrhosis.Its clinical impact is highlighted by a notable increase in patient mortality rates and a concomitant reduction in overall quality of life.Systemically,liver disease,liver function failure,portosystemic shunting,and associated multi-organ dysfunction result in the increase of disease-causing neurotoxins in the circulation,which impairs cerebral homeostasis.Key circulating neurotoxins are ammonia and inflammatory mediators.In the brain,pathophysiology is less well understood,but is thought to be driven by glial cell dysfunction.Astrocytes are the only brain resident cells that have ammonia-metabolizing machinery and are therefore putatively most susceptible to ammonia elevation.Based on a large body of mostly in vitro evidence,ammonia-induced cellular and molecular disturbances include astrocyte swelling and oxidative stress.Microglia,the brain resident macrophages,have been linked to the translation of systemic inflammation to the brain microenvironment.Recent evidence from animal studies has provided novel insights into old and new downstream effects of astrocyte and microglial dysfunction such as toxin clearance disruption and myeloid cell attraction to the central nervous system parenchyma.Furthermore,state of the art research increasingly implicates neuronal dysfunction and possibly even irreversible neuronal cell death.Cell-type specific investigation in animal models highlights the need for critical revision of the contribution of astrocytes and microglia to well-established and novel cellular and molecular alterations in hepatic encephalopathy.In this review,we therefore give a current and comprehensive overview of causes,features,and consequences of astrocyte and microglial dysfunction in hepatic encephalopathy,including areas of interest for future investigation.展开更多
The concept of the brain cognitive reserve is derived from the well-acknowledged notion that the degree of brain damage does not always match the severity of clinical symptoms and neurological/cognitive outcomes.It ha...The concept of the brain cognitive reserve is derived from the well-acknowledged notion that the degree of brain damage does not always match the severity of clinical symptoms and neurological/cognitive outcomes.It has been suggested that the size of the brain(brain reserve) and the extent of neural connections acquired through life(neural reserve) set a threshold beyond which noticeable impairments occur.In contrast,cognitive reserve refers to the brain's ability to adapt and reo rganize stru cturally and functionally to resist damage and maintain function,including neural reserve and brain maintenance,resilience,and compensation(Verkhratsky and Zorec,2024).展开更多
Ischemic stroke,a frequently occurring form of stroke,is caused by obstruction of cerebral blood flow,which leads to ischemia,hypoxia,and necrosis of local brain tissue.After ischemic stroke,both astrocytes and the bl...Ischemic stroke,a frequently occurring form of stroke,is caused by obstruction of cerebral blood flow,which leads to ischemia,hypoxia,and necrosis of local brain tissue.After ischemic stroke,both astrocytes and the blood–brain barrier undergo morphological and functional transformations.However,the interplay between astrocytes and the blood–brain barrier has received less attention.This comprehensive review explores the physiological and pathological morphological and functional changes in astrocytes and the blood–brain barrier in ischemic stroke.Post-stroke,the structure of endothelial cells and peripheral cells undergoes alterations,causing disruption of the blood–brain barrier.This disruption allows various pro-inflammatory factors and chemokines to cross the blood–brain barrier.Simultaneously,astrocytes swell and primarily adopt two phenotypic states:A1 and A2,which exhibit different roles at different stages of ischemic stroke.During the acute phase,A1 reactive astrocytes secrete vascular endothelial growth factor,matrix metalloproteinases,lipid carrier protein-2,and other cytokines,exacerbating damage to endothelial cells and tight junctions.Conversely,A2 reactive astrocytes produce pentraxin 3,Sonic hedgehog,angiopoietin-1,and other protective factors for endothelial cells.Furthermore,astrocytes indirectly influence blood–brain barrier permeability through ferroptosis and exosomes.In the middle and late(recovery)stages of ischemic stroke,A1 and A2 astrocytes show different effects on glial scar formation.A1 astrocytes promote glial scar formation and inhibit axon growth via glial fibrillary acidic protein,chondroitin sulfate proteoglycans,and transforming growth factor-β.In contrast,A2 astrocytes facilitate axon growth through platelet-derived growth factor,playing a crucial role in vascular remodeling.Therefore,enhancing our understanding of the pathological changes and interactions between astrocytes and the blood–brain barrier is a vital therapeutic target for preventing further brain damage in acute stroke.These insights may pave the way for innovative therapeutic strategies for ischemic stroke.展开更多
High mobility group box 1(HMGB1),when released extracellularly,plays a pivotal role in the development of spinal cord synapses and exacerbates autoimmune diseases within the central nervous system.In experimental auto...High mobility group box 1(HMGB1),when released extracellularly,plays a pivotal role in the development of spinal cord synapses and exacerbates autoimmune diseases within the central nervous system.In experimental autoimmune encephalomyelitis(EAE),a condition that models multiple sclerosis,the levels of extracellular HMGB1 and interleukin-33(IL-33)have been found to be inversely correlated.However,the mechanism by which IL-33 deficiency enhances HMGB1 release during EAE remains elusive.Our study elucidates a potential signaling pathway whereby the absence of IL-33 leads to increased binding of P300/CBP-associated factor with HMGB1 in the nuclei of astrocytes,upregulating HMGB1 acetylation and promoting its release from astrocyte nuclei in the spinal cord of EAE mice.Conversely,the addition of IL-33 counteracts the TNF-α-induced increase in HMGB1 and acetylated HMGB1 levels in primary astrocytes.These findings underscore the potential of IL-33-associated signaling pathways as a therapeutic target for EAE treatment.展开更多
In a recent work published in Neuron,Xu et al.identified a novel contribution of G protein-coupled receptor 37-like 1(GPR37L1),which is identified to be expressed by spinal astrocytes,to the regulation of neuropathic ...In a recent work published in Neuron,Xu et al.identified a novel contribution of G protein-coupled receptor 37-like 1(GPR37L1),which is identified to be expressed by spinal astrocytes,to the regulation of neuropathic pain[1].By interacting and enhancing the activity of glutamate transporter-1(GLT-1)in spinal astrocytes,GPR37L1 promotes glutamate uptake by spinal astrocytes and reduces excitatory synaptic transmission in the spinal dorsal horn,all of which contribute to the resolution of chronic neuropathic pain.展开更多
Spinal cord injury can be traumatic or non-traumatic in origin,with the latter rising in incidence and prevalence with the aging demographics of our society.Moreove r,as the global population ages,individuals with co-...Spinal cord injury can be traumatic or non-traumatic in origin,with the latter rising in incidence and prevalence with the aging demographics of our society.Moreove r,as the global population ages,individuals with co-existent degenerative spinal pathology comprise a growing number of traumatic spinal cord injury cases,especially involving the cervical spinal cord.This makes recovery and treatment approaches particula rly challenging as age and comorbidities may limit regenerative capacity.For these reasons,it is critical to better understand the complex milieu of spinal cord injury lesion pathobiology and the ensuing inflammatory response.This review discusses microglia-specific purinergic and cytokine signaling pathways,as well as microglial modulation of synaptic stability and plasticity after injury.Further,we evaluate the role of astrocytes in neurotransmission and calcium signaling,as well as their border-forming response to neural lesions.Both the inflammatory and reparative roles of these cells have eluded our complete understanding and remain key therapeutic targets due to their extensive structural and functional roles in the nervous system.Recent advances have shed light on the roles of glia in neurotransmission and reparative injury responses that will change how interventions are directed.Understanding key processes and existing knowledge gaps will allow future research to effectively target these cells and harness their regenerative potential.展开更多
基金supported by the National Natural Science Foundation of China(82171386,81971161,and 82201536)the Shanghai Science and Technology Development Foundation(22YF1458600)+1 种基金the Scientifc Foundation from Naval Medical University(2021QN08)the STI2030-Major Projects from Ministry of Science and Technology of China(2022ZD0204700).
文摘In the mammalian central nervous system(CNS),astrocytes are the ubiquitous glial cells that have complex morphological and molecular characteristics.These fascinating cells play essential neurosupportive and homeostatic roles in the healthy CNS and undergo morphological,molecular,and functional changes to adopt so-called‘reactive’states in response to CNS injury or disease.In recent years,interest in astrocyte research has increased dramatically and some new biological features and roles of astrocytes in physiological and pathological conditions have been discovered thanks to technological advances.Here,we will review and discuss the wellestablished and emerging astroglial biology and functions,with emphasis on their potential as therapeutic targets for CNS injury,including traumatic and ischemic injury.This review article will highlight the importance of astrocytes in the neuropathological process and repair of CNS injury.
基金supported by the National Natural Science Foundation of China,No.82201460(to YH)Nanjing Medical University Science and Technology Development Fund,No.NMUB20210202(to YH).
文摘Neurotoxic astrocytes are a promising therapeutic target for the attenuation of cerebral ischemia/reperfusion injury.Low-density lipoprotein receptor,a classic cholesterol regulatory receptor,has been found to inhibit NLR family pyrin domain containing protein 3(NLRP3)inflammasome activation in neurons following ischemic stroke and to suppress the activation of microglia and astrocytes in individuals with Alzheimer’s disease.However,little is known about the effects of low-density lipoprotein receptor on astrocytic activation in ischemic stroke.To address this issue in the present study,we examined the mechanisms by which low-density lipoprotein receptor regulates astrocytic polarization in ischemic stroke models.First,we examined low-density lipoprotein receptor expression in astrocytes via immunofluorescence staining and western blotting analysis.We observed significant downregulation of low-density lipoprotein receptor following middle cerebral artery occlusion reperfusion and oxygen-glucose deprivation/reoxygenation.Second,we induced the astrocyte-specific overexpression of low-density lipoprotein receptor using astrocyte-specific adeno-associated virus.Low-density lipoprotein receptor overexpression in astrocytes improved neurological outcomes in middle cerebral artery occlusion mice and reversed neurotoxic astrocytes to create a neuroprotective phenotype.Finally,we found that the overexpression of low-density lipoprotein receptor inhibited NLRP3 inflammasome activation in oxygen-glucose deprivation/reoxygenation injured astrocytes and that the addition of nigericin,an NLRP3 agonist,restored the neurotoxic astrocyte phenotype.These findings suggest that low-density lipoprotein receptor could inhibit the NLRP3-meidiated neurotoxic polarization of astrocytes and that increasing low-density lipoprotein receptor in astrocytes might represent a novel strategy for treating cerebral ischemic stroke.
基金supported by grants PICT 2019-08512017-2203,UBACYT and PIP CONICET(to AJR).
文摘Traumatic brain injury is a global health crisis,causing significant death and disability worldwide.Neuroinflammation that follows traumatic brain injury has serious consequences for neuronal survival and cognitive impairments,with astrocytes involved in this response.Following traumatic brain injury,astrocytes rapidly become reactive,and astrogliosis propagates from the injury core to distant brain regions.Homeostatic astroglial proteins are downregulated near the traumatic brain injury core,while pro-inflammatory astroglial genes are overexpressed.This altered gene expression is considered a pathological remodeling of astrocytes that produces serious consequences for neuronal survival and cognitive recovery.In addition,glial scar formed by reactive astrocytes is initially necessary to limit immune cell infiltration,but in the long term impedes axonal reconnection and functional recovery.Current therapeutic strategies for traumatic brain injury are focused on preventing acute complications.Statins,cannabinoids,progesterone,beta-blockers,and cerebrolysin demonstrate neuroprotective benefits but most of them have not been studied in the context of astrocytes.In this review,we discuss the cell signaling pathways activated in reactive astrocytes following traumatic brain injury and we discuss some of the potential new strategies aimed to modulate astroglial responses in traumatic brain injury,especially using cell-targeted strategies with miRNAs or lncRNA,viral vectors,and repurposed drugs.
基金supported by Fondo Nacional de Desarrollo Científico y Tecnológico(FONDECYT)#1200836,#1210644,and#1240888,and Agencia Nacional de Investigación y Desarrollo(ANID)-FONDAP#15130011(to LL)FONDECYT#3230227(to MFG).
文摘Astrocytes are the most abundant type of glial cell in the central nervous system.Upon injury and inflammation,astrocytes become reactive and undergo morphological and functional changes.Depending on their phenotypic classification as A1 or A2,reactive astrocytes contribute to both neurotoxic and neuroprotective responses,respectively.However,this binary classification does not fully capture the diversity of astrocyte responses observed across different diseases and injuries.Transcriptomic analysis has revealed that reactive astrocytes have a complex landscape of gene expression profiles,which emphasizes the heterogeneous nature of their reactivity.Astrocytes actively participate in regulating central nervous system inflammation by interacting with microglia and other cell types,releasing cytokines,and influencing the immune response.The phosphoinositide 3-kinase(PI3K)/protein kinase B(AKT)signaling pathway is a central player in astrocyte reactivity and impacts various aspects of astrocyte behavior,as evidenced by in silico,in vitro,and in vivo results.In astrocytes,inflammatory cues trigger a cascade of molecular events,where nuclear factor-κB serves as a central mediator of the pro-inflammatory responses.Here,we review the heterogeneity of reactive astrocytes and the molecular mechanisms underlying their activation.We highlight the involvement of various signaling pathways that regulate astrocyte reactivity,including the PI3K/AKT/mammalian target of rapamycin(mTOR),αvβ3 integrin/PI3K/AKT/connexin 43,and Notch/PI3K/AKT pathways.While targeting the inactivation of the PI3K/AKT cellular signaling pathway to control reactive astrocytes and prevent central nervous system damage,evidence suggests that activating this pathway could also yield beneficial outcomes.This dual function of the PI3K/AKT pathway underscores its complexity in astrocyte reactivity and brain function modulation.The review emphasizes the importance of employing astrocyte-exclusive models to understand their functions accurately and these models are essential for clarifying astrocyte behavior.The findings should then be validated using in vivo models to ensure real-life relevance.The review also highlights the significance of PI3K/AKT pathway modulation in preventing central nervous system damage,although further studies are required to fully comprehend its role due to varying factors such as different cell types,astrocyte responses to inflammation,and disease contexts.Specific strategies are clearly necessary to address these variables effectively.
基金supported by a National Research Foundation of Korea(NRF)grant funded by the Korean government(2017R1A5A2015391 and 2020M3E5D9079764)(to KS).
文摘Astrocytes are functionally dynamic cells that support neurons in multiple ways throughout an organism’s lifespan.The astrocytic regulation of neuronal activity has been increasingly recognized in recent years.Astrocytes are now recognized as playing a more complex role than mere bystanders in the central nervous system.However,their role in regulating the sleep neurocircuitry is not well understood.From this perspective,we highlight the role of astrocytes in sleep modulation,with a particular focus on regulatory mechanisms related to the ventrolateral preoptic nucleus(VLPO)of the hypothalamus.We briefly discuss recent literature reporting the role of VLPO astrocytes in regulating sleep-associated behaviors.
基金supported by the National Natural Science Foundation of China,Nos.32371070 (to JT),31761163005 (to JT),32100824 (to QX)the Shenzhen Science and Technology Program,Nos.RCBS20210609104606024 (to QX),JCY20210324101813035 (to DL)+4 种基金the Guangdong Provincial Key S&T Program,No.2018B030336001 (to JT)the Key Basic Research Program of Shenzhen Science and Technology Innovation Commission,Nos.JCYJ20200109115405930 (to JT),JCYJ20220818101615033 (to DL),JCYJ20210324115811031 (to QX),JCYJ20200109150717745 (to QX)Shenzhen Key Laboratory of Neuroimmunomodulation for Neurological Diseases,No.ZDSYS20220304163558001 (to JT)Guangdong Provincial Key Laboratory of Brain Connectome and Behavior,No.2023B1212060055 (to JT)the China Postdoctoral Science Foundation,No.2021M693298 (to QX)。
文摘The conventional perception of astrocytes as mere supportive cells within the brain has recently been called into question by empirical evidence, which has revealed their active involvement in regulating brain function and encoding behaviors associated with emotions.Specifically, astrocytes in the basolateral amygdala have been found to play a role in the modulation of anxiety-like behaviors triggered by chronic stress. Nevertheless, the precise molecular mechanisms by which basolateral amygdala astrocytes regulate chronic stress–induced anxiety-like behaviors remain to be fully elucidated. In this study, we found that in a mouse model of anxiety triggered by unpredictable chronic mild stress, the expression of excitatory amino acid transporter 2 was upregulated in the basolateral amygdala. Interestingly, our findings indicate that the targeted knockdown of excitatory amino acid transporter 2 specifically within the basolateral amygdala astrocytes was able to rescue the anxiety-like behavior in mice subjected to stress. Furthermore, we found that the overexpression of excitatory amino acid transporter 2 in the basolateral amygdala, whether achieved through intracranial administration of excitatory amino acid transporter 2agonists or through injection of excitatory amino acid transporter 2-overexpressing viruses with GfaABC1D promoters, evoked anxiety-like behavior in mice. Our single-nucleus RNA sequencing analysis further confirmed that chronic stress induced an upregulation of excitatory amino acid transporter 2 specifically in astrocytes in the basolateral amygdala. Moreover, through in vivo calcium signal recordings, we found that the frequency of calcium activity in the basolateral amygdala of mice subjected to chronic stress was higher compared with normal mice.After knocking down the expression of excitatory amino acid transporter 2 in the basolateral amygdala, the frequency of calcium activity was not significantly increased, and anxiety-like behavior was obviously mitigated. Additionally, administration of an excitatory amino acid transporter 2 inhibitor in the basolateral amygdala yielded a notable reduction in anxiety level among mice subjected to stress. These results suggest that basolateral amygdala astrocytic excitatory amino acid transporter 2 plays a role in in the regulation of unpredictable chronic mild stress-induced anxiety-like behavior by impacting the activity of local glutamatergic neurons, and targeting excitatory amino acid transporter 2 in the basolateral amygdala holds therapeutic promise for addressing anxiety disorders.
基金supported by the National Natural Science Foundation of China, Nos.81971151 (to YW), 82102528 (to XL), 82102583 (to LW)the Natural Science Foundation of Guangdong Province, China, Nos.2020A1515010265 (to YW), 2020A1515110679 (to XL), and 2021A1515010358 (to XL)
文摘Invasive inflammation and excessive scar formation are the main reasons for the difficulty in repairing nervous tissue after spinal cord injury.Microglia and astrocytes play key roles in the spinal cord injury micro-environment and share a close interaction.However,the mechanisms involved remain unclear.In this study,we found that after spinal cord injury,resting microglia(M0)were polarized into pro-inflammatory phenotypes(MG1 and MG3),while resting astrocytes were polarized into reactive and scar-forming phenotypes.The expression of growth arrest-specific 6(Gas6)and its receptor Axl were significantly down-regulated in microglia and astrocytes after spinal cord injury.In vitro experiments showed that Gas6 had negative effects on the polarization of reactive astrocytes and pro-inflammatory microglia,and even inhibited the cross-regulation between them.We further demonstrated that Gas6 can inhibit the polarization of reactive astrocytes by suppressing the activation of the Yes-associated protein signaling pathway.This,in turn,inhibited the polarization of pro-inflammatory microglia by suppressing the activation of the nuclear factor-κB/p65 and Janus kinase/signal transducer and activator of transcription signaling pathways.In vivo experiments showed that Gas6 inhibited the polarization of pro-inflammatory microglia and reactive astrocytes in the injured spinal cord,thereby promoting tissue repair and motor function recovery.Overall,Gas6 may play a role in the treatment of spinal cord injury.It can inhibit the inflammatory pathway of microglia and polarization of astrocytes,attenuate the interaction between microglia and astrocytes in the inflammatory microenvironment,and thereby alleviate local inflammation and reduce scar formation in the spinal cord.
基金supported by the National Natural Science Foundation of China,No.8227050826(to PL)Tianjin Science and Technology Bureau Foundation,No.20201194(to PL)Tianjin Graduate Research and Innovation Project,No.2022BKY174(to CW).
文摘Cerebral edema caused by blood-brain barrier injury after intracerebral hemorrhage is an important factor leading to poor prognosis.Human-induced pluripotent stem cell-derived neural stem cell exosomes(hiPSC-NSC-Exos)have shown potential for brain injury repair in central nervous system diseases.In this study,we explored the impact of hiPSC-NSC-Exos on blood-brain barrier preservation and the underlying mechanism.Our results indicated that intranasal delivery of hiPSC-NSC-Exos mitigated neurological deficits,enhanced blood-brain barrier integrity,and reduced leukocyte infiltration in a mouse model of intracerebral hemorrhage.Additionally,hiPSC-NSC-Exos decreased immune cell infiltration,activated astrocytes,and decreased the secretion of inflammatory cytokines like monocyte chemoattractant protein-1,macrophage inflammatory protein-1α,and tumor necrosis factor-αpost-intracerebral hemorrhage,thereby improving the inflammatory microenvironment.RNA sequencing indicated that hiPSC-NSC-Exo activated the PI3K/AKT signaling pathway in astrocytes and decreased monocyte chemoattractant protein-1 secretion,thereby improving blood-brain barrier integrity.Treatment with the PI3K/AKT inhibitor LY294002 or the monocyte chemoattractant protein-1 neutralizing agent C1142 abolished these effects.In summary,our findings suggest that hiPSC-NSC-Exos maintains blood-brain barrier integrity,in part by downregulating monocyte chemoattractant protein-1 secretion through activation of the PI3K/AKT signaling pathway in astrocytes.
基金supported by the National Natural Science Foundation of China,No.82001325Visiting Scholar Foundation of Shandong Province,No.20236-01(both to CS).
文摘Stroke is the leading cause of mortality globally,ultimately leading to severe,lifelong neurological impairments.Patients often suffer from a secondary cascade of damage,including neuroinflammation,cytotoxicity,oxidative stress,and mitochondrial dysfunction.Regrettably,there is a paucity of clinically available therapeutics to address these issues.Emerging evidence underscores the pivotal roles of astrocytes,the most abundant glial cells in the brain,throughout the various stages of ischemic stroke.In this comprehensive review,we initially provide an overview of the fundamental physiological functions of astrocytes in the brain,emphasizing their critical role in modulating neuronal homeostasis,synaptic activity,and blood-brain barrier integrity.We then delve into the growing body of evidence that highlights the functional diversity and heterogeneity of astrocytes in the context of ischemic stroke.Their well-established contributions to energy provision,metabolic regulation,and neurotransmitter homeostasis,as well as their emerging roles in mitochondrial recovery,neuroinflammation regulation,and oxidative stress modulation following ischemic injury,are discussed in detail.We also explore the cellular and molecular mechanisms underpinning these functions,with particular emphasis on recently identified targets within astrocytes that offer promising prospects for therapeutic intervention.In the final section of this review,we offer a detailed overview of the current therapeutic strategies targeting astrocytes in the treatment of ischemic stroke.These astrocyte-targeting strategies are categorized into traditional small-molecule drugs,microRNAs(miRNAs),stem cell-based therapies,cellular reprogramming,hydrogels,and extracellular vesicles.By summarizing the current understanding of astrocyte functions and therapeutic targeting approaches,we aim to highlight the critical roles of astrocytes during and after stroke,particularly in the pathophysiological development in ischemic stroke.We also emphasize promising avenues for novel,astrocyte-targeted therapeutics that could become clinically available options,ultimately improving outcomes for patients with stroke.
基金supported by the STI2030-Major Projects(2022ZD0205202)Anhui Provincial Natural Science Foundation(2408085Y043)National Natural Science Foundation of China(82471540,32030046,32200798)。
文摘Astrocytes are associated with varying brain size between rodents and primates.As a close evolutionary relative of primates,the tree shrew(Tupaia belangeri)provides a valuable comparative model for investigating glial architecture.However,the anatomical distribution and morphological characteristics of astrocytes in the tree shrew brain remain poorly characterized.In this study,glial fibrillary acidic protein(GFAP)immunofluorescence was employed to systematically examine the spatial distribution and morphology of astrocytes in the whole brain of tree shrews.Notably,GFAP-immunoreactive(ir)astrocytes were detected throughout the telencephalon,diencephalon,mesencephalon,metencephalon,and myelencephalon.Distinct laminar distribution was evident in regions such as the main olfactory bulb and hippocampus.Semi-quantitative comparisons revealed significant regional differences in astrocyte density between tree shrews and mice,encompassing the main olfactory bulb,accessory olfactory bulb,olfactory tubercle,cortex,hippocampus,cortical amygdaloid nucleus,hypothalamus,thalamus,superior colliculus,interpeduncular nucleus,median raphe nucleus,and parabrachial nucleus.Compared to mice,tree shrews exhibited higher astrocyte density with increased morphological complexity in the posterior hypothalamic nucleus,dorsomedial hypothalamic nucleus,ventromedial hypothalamic nucleus,and periaqueductal gray,but lower density with greater morphological complexity in the hippocampus and substantia nigra.In the paraventricular hypothalamic nucleus and lateral hypothalamic area,GFAP-ir astrocytes displayed comparable densities between tree shrews and mice but exhibited region-specific differences in morphological complexity.This study provides the first brain-wide mapping of GFAP-ir astrocytes in tree shrews,revealing marked interspecies differences in their distribution and morphology,and establishing a neuroanatomical framework for understanding astrocyte involvement in diverse physiological and behavioral functions.
文摘Background:The inability of damaged neurons to regenerate and of axons to estab-lish new functional connections leads to permanent functional deficits after spinal cord injury(SCI).Although astrocyte reprogramming holds promise for neurorepair in various disease models,it is not sufficient on its own to achieve significant functional recovery.Methods:A rat SCI model was established using a spinal cord impactor.Seven days postsurgery,adeno-associated virus were injected to overexpress the transcription factors NeuroD1 and Neurogenin-2(Ngn2)in the spinal cord.The rats were then trained to walk on a weight-supported treadmill for 4 weeks,starting 14 days after modeling.The effects of these interventions on motor and sensory functions,as well as spinal cord tissue repair,were subsequently evaluated.Results:The combination of NeuroD1 and Ngn2 overexpression with weight-supported exercise training significantly improved gait compared to either inter-vention alone.The group receiving the combined intervention exhibited enhanced sensitivity in sensory assessments.Immunofluorescence analysis revealed increased colocalization of astrocytes and microtubule-associated protein 2-positive neurons in the injury area.These effects were more pronounced than those observed with spinal cord tissue repair alone.Additionally,the combined intervention significantly reduced glial scarring and the size of the injury area.Conclusion:Exercise intervention enhances the reprogramming effects of astrocytes and restores motor function,yielding better results than either intervention alone.
基金supported by the National Natural Science Foundation of China(82171455).
文摘Hemorrhagic shock is a common clinical emergency that can aggravate cell injury after resuscitation.Astrocytes are crucial for the survival of neurons because they regulate the surrounding ionic microenvironment of neurons.Although hemorrhagic shock and resuscitation(HSR)injury can impair cognition,it remains unclear how this insult directly affects astrocytes.In this study,we established an HSR model by bleeding and re-transfusion in mice.The social interaction test and new object recognition test were applied to evaluate post-operative cognitive changes,and the results suggest that mice experience cognitive impairment following exposure to HSR.In the HSR group,the power spectral density ofβandγoscillations decreased,and the coupling of theθoscillation phase andγoscillation amplitude was abnormal,which indicated abnormal neuronal oscillation and cognitive impairment after HSR exposure.In brief,cognitive impairment in mice is strongly correlated with Ca^(2+)signal strength in lateral septum astrocytes following HSR.
基金supported by the National Natural Science Foundation of China,Nos.82071383,82371392(to BN)the Natural Science Foundation of Shandong Province of China(Key Project),No.ZR2020KH007(to BN)+1 种基金“Taishan Scholar Distinguished Expert Program”of Shandong Province,No.tstp20231257(to BN)Health Commission Science and Technology Plan Project of Jinan,No.2023-1-8(to YZ).
文摘Lactate serves as a key energy metabolite in the central nervous system,facilitating essential brain functions,including energy supply,signaling,and epigenetic modulation.Moreover,it links epigenetic modifications with metabolic reprogramming.Nonetheless,the specific mechanisms and roles of this connection in astrocytes remain unclear.Therefore,this review aims to explore the role and specific mechanisms of lactate in the metabolic reprogramming of astrocytes in the central nervous system.The close relationship between epigenetic modifications and metabolic reprogramming was discussed.Therapeutic strategies for targeting metabolic reprogramming in astrocytes in the central nervous system were also outlined to guide future research in central nervous system diseases.In the nervous system,lactate plays an essential role.However,its mechanism of action as a bridge between metabolic reprogramming and epigenetic modifications in the nervous system requires future investigation.The involvement of lactate in epigenetic modifications is currently a hot research topic,especially in lactylation modification,a key determinant in this process.Lactate also indirectly regulates various epigenetic modifications,such as N6-methyladenosine,acetylation,ubiquitination,and phosphorylation modifications,which are closely linked to several neurological disorders.In addition,exploring the clinical applications and potential therapeutic strategies of lactic acid provides new insights for future neurological disease treatments.
基金supported by the National Key Research and Development Program of China,No. 2023YFF0714200 (to CW)the National Natural Science Foundation of China,Nos. 82472038 and 82202224 (both to CW)+3 种基金the Shanghai Rising-Star Program,No. 23QA1407700 (to CW)the Construction Project of Shanghai Key Laboratory of Molecular Imaging,No. 18DZ2260400 (to CW)the National Science Foundation for Distinguished Young Scholars,No. 82025019 (to CL)the Greater Bay Area Institute of Precision Medicine (Guangzhou)(to CW)。
文摘Epilepsy is a leading cause of disability and mortality worldwide. However, despite the availability of more than 20 antiseizure medications, more than one-third of patients continue to experience seizures. Given the urgent need to explore new treatment strategies for epilepsy, recent research has highlighted the potential of targeting gliosis, metabolic disturbances, and neural circuit abnormalities as therapeutic strategies. Astrocytes, the largest group of nonneuronal cells in the central nervous system, play several crucial roles in maintaining ionic and energy metabolic homeostasis in neurons, regulating neurotransmitter levels, and modulating synaptic plasticity. This article briefly reviews the critical role of astrocytes in maintaining balance within the central nervous system. Building on previous research, we discuss how astrocyte dysfunction contributes to the onset and progression of epilepsy through four key aspects: the imbalance between excitatory and inhibitory neuronal signaling, dysregulation of metabolic homeostasis in the neuronal microenvironment, neuroinflammation, and the formation of abnormal neural circuits. We summarize relevant basic research conducted over the past 5 years that has focused on modulating astrocytes as a therapeutic approach for epilepsy. We categorize the therapeutic targets proposed by these studies into four areas: restoration of the excitation–inhibition balance, reestablishment of metabolic homeostasis, modulation of immune and inflammatory responses, and reconstruction of abnormal neural circuits. These targets correspond to the pathophysiological mechanisms by which astrocytes contribute to epilepsy. Additionally, we need to consider the potential challenges and limitations of translating these identified therapeutic targets into clinical treatments. These limitations arise from interspecies differences between humans and animal models, as well as the complex comorbidities associated with epilepsy in humans. We also highlight valuable future research directions worth exploring in the treatment of epilepsy and the regulation of astrocytes, such as gene therapy and imaging strategies. The findings presented in this review may help open new therapeutic avenues for patients with drugresistant epilepsy and for those suffering from other central nervous system disorders associated with astrocytic dysfunction.
基金supported by grants from the Research Foundation–Flanders(11A6420N,1268823N to WC and LVH)a FWO Junior Research Project Grant(G055121N to REV)VIB.AG is a senior clinical researcher of the Research Foundation–Flanders(1805718N)。
文摘Hepatic encephalopathy,defined as neuropsychiatric dysfunction secondary to liver disease,is a frequent decompensating event in cirrhosis.Its clinical impact is highlighted by a notable increase in patient mortality rates and a concomitant reduction in overall quality of life.Systemically,liver disease,liver function failure,portosystemic shunting,and associated multi-organ dysfunction result in the increase of disease-causing neurotoxins in the circulation,which impairs cerebral homeostasis.Key circulating neurotoxins are ammonia and inflammatory mediators.In the brain,pathophysiology is less well understood,but is thought to be driven by glial cell dysfunction.Astrocytes are the only brain resident cells that have ammonia-metabolizing machinery and are therefore putatively most susceptible to ammonia elevation.Based on a large body of mostly in vitro evidence,ammonia-induced cellular and molecular disturbances include astrocyte swelling and oxidative stress.Microglia,the brain resident macrophages,have been linked to the translation of systemic inflammation to the brain microenvironment.Recent evidence from animal studies has provided novel insights into old and new downstream effects of astrocyte and microglial dysfunction such as toxin clearance disruption and myeloid cell attraction to the central nervous system parenchyma.Furthermore,state of the art research increasingly implicates neuronal dysfunction and possibly even irreversible neuronal cell death.Cell-type specific investigation in animal models highlights the need for critical revision of the contribution of astrocytes and microglia to well-established and novel cellular and molecular alterations in hepatic encephalopathy.In this review,we therefore give a current and comprehensive overview of causes,features,and consequences of astrocyte and microglial dysfunction in hepatic encephalopathy,including areas of interest for future investigation.
文摘The concept of the brain cognitive reserve is derived from the well-acknowledged notion that the degree of brain damage does not always match the severity of clinical symptoms and neurological/cognitive outcomes.It has been suggested that the size of the brain(brain reserve) and the extent of neural connections acquired through life(neural reserve) set a threshold beyond which noticeable impairments occur.In contrast,cognitive reserve refers to the brain's ability to adapt and reo rganize stru cturally and functionally to resist damage and maintain function,including neural reserve and brain maintenance,resilience,and compensation(Verkhratsky and Zorec,2024).
基金supported by the National Natural Science Foundation of China,No.U21A20400(to QW)the National Natural Science Foundation of China,No.82104560(to CL)+1 种基金the Natural Science Foundation of Beijing,No.7232279(to XW)the Project of Beijing University of Chinese Medicine,Nos.2024-JYB-JBZD-043(to CL),2022-JYB-JBZR-004(to XW)。
文摘Ischemic stroke,a frequently occurring form of stroke,is caused by obstruction of cerebral blood flow,which leads to ischemia,hypoxia,and necrosis of local brain tissue.After ischemic stroke,both astrocytes and the blood–brain barrier undergo morphological and functional transformations.However,the interplay between astrocytes and the blood–brain barrier has received less attention.This comprehensive review explores the physiological and pathological morphological and functional changes in astrocytes and the blood–brain barrier in ischemic stroke.Post-stroke,the structure of endothelial cells and peripheral cells undergoes alterations,causing disruption of the blood–brain barrier.This disruption allows various pro-inflammatory factors and chemokines to cross the blood–brain barrier.Simultaneously,astrocytes swell and primarily adopt two phenotypic states:A1 and A2,which exhibit different roles at different stages of ischemic stroke.During the acute phase,A1 reactive astrocytes secrete vascular endothelial growth factor,matrix metalloproteinases,lipid carrier protein-2,and other cytokines,exacerbating damage to endothelial cells and tight junctions.Conversely,A2 reactive astrocytes produce pentraxin 3,Sonic hedgehog,angiopoietin-1,and other protective factors for endothelial cells.Furthermore,astrocytes indirectly influence blood–brain barrier permeability through ferroptosis and exosomes.In the middle and late(recovery)stages of ischemic stroke,A1 and A2 astrocytes show different effects on glial scar formation.A1 astrocytes promote glial scar formation and inhibit axon growth via glial fibrillary acidic protein,chondroitin sulfate proteoglycans,and transforming growth factor-β.In contrast,A2 astrocytes facilitate axon growth through platelet-derived growth factor,playing a crucial role in vascular remodeling.Therefore,enhancing our understanding of the pathological changes and interactions between astrocytes and the blood–brain barrier is a vital therapeutic target for preventing further brain damage in acute stroke.These insights may pave the way for innovative therapeutic strategies for ischemic stroke.
基金supported by the National Natural Science Foundation of China(82001281 and 82371195)Hubei Provincial Natural Science Foundation of China for Distinguished Young Scholars(2022CFA104)the Research Fund of Jianghan University(2022XKZX28).
文摘High mobility group box 1(HMGB1),when released extracellularly,plays a pivotal role in the development of spinal cord synapses and exacerbates autoimmune diseases within the central nervous system.In experimental autoimmune encephalomyelitis(EAE),a condition that models multiple sclerosis,the levels of extracellular HMGB1 and interleukin-33(IL-33)have been found to be inversely correlated.However,the mechanism by which IL-33 deficiency enhances HMGB1 release during EAE remains elusive.Our study elucidates a potential signaling pathway whereby the absence of IL-33 leads to increased binding of P300/CBP-associated factor with HMGB1 in the nuclei of astrocytes,upregulating HMGB1 acetylation and promoting its release from astrocyte nuclei in the spinal cord of EAE mice.Conversely,the addition of IL-33 counteracts the TNF-α-induced increase in HMGB1 and acetylated HMGB1 levels in primary astrocytes.These findings underscore the potential of IL-33-associated signaling pathways as a therapeutic target for EAE treatment.
基金supported by the National Natural Science Foundation of China(82474625)Zhejiang Provincial Natural Science Funds(LZ23H270001).
文摘In a recent work published in Neuron,Xu et al.identified a novel contribution of G protein-coupled receptor 37-like 1(GPR37L1),which is identified to be expressed by spinal astrocytes,to the regulation of neuropathic pain[1].By interacting and enhancing the activity of glutamate transporter-1(GLT-1)in spinal astrocytes,GPR37L1 promotes glutamate uptake by spinal astrocytes and reduces excitatory synaptic transmission in the spinal dorsal horn,all of which contribute to the resolution of chronic neuropathic pain.
基金supported by the Robert Campeau Family Foundation/Dr.C.H.Tator Chair in Brain and Spinal Cord Research(to MGF)。
文摘Spinal cord injury can be traumatic or non-traumatic in origin,with the latter rising in incidence and prevalence with the aging demographics of our society.Moreove r,as the global population ages,individuals with co-existent degenerative spinal pathology comprise a growing number of traumatic spinal cord injury cases,especially involving the cervical spinal cord.This makes recovery and treatment approaches particula rly challenging as age and comorbidities may limit regenerative capacity.For these reasons,it is critical to better understand the complex milieu of spinal cord injury lesion pathobiology and the ensuing inflammatory response.This review discusses microglia-specific purinergic and cytokine signaling pathways,as well as microglial modulation of synaptic stability and plasticity after injury.Further,we evaluate the role of astrocytes in neurotransmission and calcium signaling,as well as their border-forming response to neural lesions.Both the inflammatory and reparative roles of these cells have eluded our complete understanding and remain key therapeutic targets due to their extensive structural and functional roles in the nervous system.Recent advances have shed light on the roles of glia in neurotransmission and reparative injury responses that will change how interventions are directed.Understanding key processes and existing knowledge gaps will allow future research to effectively target these cells and harness their regenerative potential.
