Astrocytes are the most abundant glial cells in the central nervous system;they participate in crucial biological processes,maintain brain structure,and regulate nervous system function.Exosomes are cell-derived extra...Astrocytes are the most abundant glial cells in the central nervous system;they participate in crucial biological processes,maintain brain structure,and regulate nervous system function.Exosomes are cell-derived extracellular vesicles containing various bioactive molecules including proteins,peptides,nucleotides,and lipids secreted from their cellular sources.Increasing evidence shows that exosomes participate in a communication network in the nervous system,in which astrocyte-derived exosomes play important roles.In this review,we have summarized the effects of exosomes targeting astrocytes and the astrocyte-derived exosomes targeting other cell types in the central nervous system.We also discuss the potential research directions of the exosome-based communication network in the nervous system.The exosome-based intercellular communication focused on astrocytes is of great significance to the biological and/or pathological processes in different conditions in the brain.New strategies may be developed for the diagnosis and treatment of neurological disorders by focusing on astrocytes as the central cells and utilizing exosomes as communication mediators.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
In situ direct reprogramming technology can directly convert endogenous glial cells into functional neurons in vivo for central nervous system repair. Polypyrimidine tract-binding protein 1(PTB) knockdown has been sho...In situ direct reprogramming technology can directly convert endogenous glial cells into functional neurons in vivo for central nervous system repair. Polypyrimidine tract-binding protein 1(PTB) knockdown has been shown to reprogram astrocytes to functional neurons in situ. In this study, we used AAV-PHP.e B-GFAP-sh PTB to knockdown PTB in a mouse model of ischemic stroke induced by endothelin-1, and investigated the effects of GFAP-sh PTB-mediated direct reprogramming to neurons. Our results showed that in the mouse model of ischemic stroke, PTB knockdown effectively reprogrammed GFAP-positive cells to neurons in ischemic foci, restored neural tissue structure, reduced inflammatory response, and improved behavioral function. These findings validate the effectiveness of in situ transdifferentiation of astrocytes, and suggest that the approach may be a promising strategy for stroke treatment.展开更多
Alzheimer's disease(AD)is characterized by complex etiology,long-lasting pathogenesis,and celltype-specific alterations.Currently,there is no cure for AD,emphasizing the urgent need for a comprehensive understandi...Alzheimer's disease(AD)is characterized by complex etiology,long-lasting pathogenesis,and celltype-specific alterations.Currently,there is no cure for AD,emphasizing the urgent need for a comprehensive understanding of cell-specific pathology.Astrocytes,principal homeostatic cells of the central nervous system,are key players in the pathogenesis of neurodegenerative diseases,including AD.Cellular models greatly facilitate the investigation of cell-specific pathological alterations and the dissection of molecular mechanisms and pathways.Tumor-derived and immortalized astrocytic cell lines,alongside the emerging technology of adult induced pluripotent stem cells,are widely used to study cellular dysfunction in AD.Surprisingly,no stable cell lines were available from genetic mouse AD models.Recently,we established immortalized hippocampal astroglial cell lines from amyloid-βprecursor protein/presenilin-1/Tau triple-transgenic(3xTg)-AD mice(denominated as wild type(WT)-and 3Tg-iAstro cells)using retrovirus-mediated transduction of simian virus 40 large T-antigen and propagation without clonal selection,thereby maintaining natural heterogeneity of primary cultures.Several groups have successfully used 3Tg-iAstro cells for single-cell and omics approaches to study astrocytic AD-related alterations of calcium signaling,mitochondrial dysfunctions,disproteostasis,altered homeostatic and signaling support to neurons,and blood-brain barrier models.Here we provide a comparative overview of the most used models to study astrocytes in vitro,such as primary culture,tumor-derived cell lines,immortalized astroglial cell lines,and induced pluripotent stem cell-derived astrocytes.We conclude that immortalized WT-and 3Tg-iAstro cells provide a noncompetitive but complementary,low-cost,easy-to-handle,and versatile cellular model for dissection of astrocyte-specific AD-related alterations and preclinical drug discovery.展开更多
Astrocytes and microglia play an orchestrated role following spinal cord injury;however,the molecular mechanisms through which microglia regulate astrocytes after spinal cord injury are not yet fully understood.Herein...Astrocytes and microglia play an orchestrated role following spinal cord injury;however,the molecular mechanisms through which microglia regulate astrocytes after spinal cord injury are not yet fully understood.Herein,microglia were pharmacologically depleted and the effects on the astrocytic response were examined.We further explored the potential mechanisms involving the signal transducers and activators of transcription 3(STAT3)pathway.For in vivo experiments,we constructed a contusion spinal cord injury model in C57BL/6 mice.To deplete microglia,all mice were treated with colony-stimulating factor 1 receptor inhibitor PLX3397,starting 2 weeks prior to surgery until they were sacrificed.Cell proliferation was examined by 5-ethynyl-2-deoxyuridine(EdU)and three pivotal inflammatory cytokines were detected by a specific Bio-Plex Pro^(TM) Reagent Kit.Locomotor function,neuroinflammation,astrocyte activation and phosphorylated STAT3(pSTAT3,a maker of activation of STAT3 signaling)levels were determined.For in vitro experiments,a microglia and astrocyte coculture system was established,and the small molecule STA21,which blocks STAT3 activation,was applied to investigate whether STAT3 signaling is involved in mediating astrocyte proliferation induced by microglia.PLX3397 administration disrupted glial scar formation,increased inflammatory spillover,induced diffuse tissue damage and impaired functional recovery after spinal cord injury.Microglial depletion markedly reduced EdU+proliferating cells,especially proliferating astrocytes at 7 days after spinal cord injury.RNA sequencing analysis showed that the JAK/STAT3 pathway was downregulated in mice treated with PLX3397.Double immunofluorescence staining confirmed that PLX3397 significantly decreased STAT3 expression in astrocytes.Importantly,in vitro coculture of astrocytes and microglia showed that microglia-induced astrocyte proliferation was abolished by STA21 administration.These findings suggest that microglial depletion impaired astrocyte proliferation and astrocytic scar formation,and induced inflammatory diffusion partly by inhibiting STAT3 phosphorylation in astrocytes following spinal cord injury.展开更多
Astrocytes,a subtype of glial cells,are star-shaped cells that are involved in the homeostasis and blood flow control of the central nervous system(CNS).They are known to provide structural and functional support to n...Astrocytes,a subtype of glial cells,are star-shaped cells that are involved in the homeostasis and blood flow control of the central nervous system(CNS).They are known to provide structural and functional support to neurons,including the regulation of neuronal activation through extracellular ion concentrations,the regulation of energy dynamics in the brain through the transfer of lactate to neurons,and the modulation of synaptic transmission via the release of neurotransmitters such as glutamate and adenosine triphosphate.In addition,astrocytes play a critical role in neuronal reconstruction after brain injury,including neurogenesis,synaptogenesis,angiogenesis,repair of the blood-brain barrier,and glial scar formation after traumatic brain injury(Zhou et al.,2020).展开更多
Neuroinflammation and the NACHT,LRR,and PYD domains-containing protein 3 inflammasome play crucial roles in secondary tissue damage following an initial insult in patients with traumatic brain injury(TBI).Maraviroc,a ...Neuroinflammation and the NACHT,LRR,and PYD domains-containing protein 3 inflammasome play crucial roles in secondary tissue damage following an initial insult in patients with traumatic brain injury(TBI).Maraviroc,a C-C chemokine receptor type 5 antagonist,has been viewed as a new therapeutic strategy for many neuroinflammatory diseases.We studied the effect of maraviroc on TBI-induced neuroinflammation.A moderate-TBI mouse model was subjected to a controlled cortical impact device.Maraviroc or vehicle was injected intraperitoneally 1 hour after TBI and then once per day for 3 consecutive days.Western blot,immunohistochemistry,and TUNEL(terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling)analyses were performed to evaluate the molecular mechanisms of maraviroc at 3 days post-TBI.Our results suggest that maraviroc administration reduced NACHT,LRR,and PYD domains-containing protein 3 inflammasome activation,modulated microglial polarization from M1 to M2,decreased neutrophil and macrophage infiltration,and inhibited the release of inflammatory factors after TBI.Moreover,maraviroc treatment decreased the activation of neurotoxic reactive astrocytes,which,in turn,exacerbated neuronal cell death.Additionally,we confirmed the neuroprotective effect of maraviroc using the modified neurological severity score,rotarod test,Morris water maze test,and lesion volume measurements.In summary,our findings indicate that maraviroc might be a desirable pharmacotherapeutic strategy for TBI,and C-C chemokine receptor type 5 might be a promising pharmacotherapeutic target to improve recovery after TBI.展开更多
The trigeminal root entry zone is the zone at which the myelination switches from peripheral Schwann cells to central oligodendrocytes.Its special anatomical and physiological structure renders it susceptible to nerve...The trigeminal root entry zone is the zone at which the myelination switches from peripheral Schwann cells to central oligodendrocytes.Its special anatomical and physiological structure renders it susceptible to nerve injury.The etiology of most primary trigeminal neuralgia is closely related to microvascular compression of the trigeminal root entry zone.This study aimed to develop an efficient in vitro model mimicking the glial environment of trigeminal root entry zone as a tool to investigate the effects of glial cell line-derived neurotrophic factor and brain-derived neurotrophic factor on the structural and functional integrity of trigeminal root entry zone and modulation of cellular interactions.Primary astrocytes and Schwann cells isolated from trigeminal root entry zone of postnatal rats were inoculated into a two-well silicon culture insert to mimic the trigeminal root entry zone microenvironment and treated with glial cell line-derived neurotrophic factor and brain-derived neurotrophic factor.In monoculture,glial cell line-derived neurotrophic factor promoted the migration of Schwann cells,but it did not have effects on the migration of astrocytes.In the co-culture system,glial cell line-derived neurotrophic factor promoted the bidirectional migration of astrocytes and Schwann cells.Brain-derived neurotrophic factor markedly promoted the activation and migration of astrocytes.However,in the co-culture system,brain-derived neurotrophic factor inhibited the migration of astrocytes and Schwann cells to a certain degree.These findings suggest that glial cell line-derived neurotrophic factor and brain-derived neurotrophic factor are involved in the regulation of the astrocyte-Schwann cell interaction in the co-culture system derived from the trigeminal root entry zone.This system can be used as a cell model to study the mechanism of glial dysregulation associated with trigeminal nerve injury and possible therapeutic interventions.展开更多
Astrocytes are key cells in the central nervous system.They are involved in many important functions under physiological and pathological conditions.As part of neuroglia,they have been recognised as cellular elements ...Astrocytes are key cells in the central nervous system.They are involved in many important functions under physiological and pathological conditions.As part of neuroglia,they have been recognised as cellular elements in their own right.The name astrocyte was first proposed by Mihaly von Lenhossek in 1895 because of the finely branched processes and star-like appearance of these particular cells.As early as the late 19th and early 20th centuries,Ramon y Cajal and Camillo Golgi had noted that although astrocytes have stellate features,their morphology is extremely diverse.Modern research has confirmed the morphological diversity of astrocytes both in vitro and in vivo and their complex,specific,and important roles in the central nervous system.In this review,the functions of astrocytes and their roles are described.展开更多
Blood-brain barrier disruption occurs in the early stages of Alzheimer’s disease.Recent studies indicate a link between blood-brain barrier dysfunction and cognitive decline and might accelerate Alzheimer’s disease ...Blood-brain barrier disruption occurs in the early stages of Alzheimer’s disease.Recent studies indicate a link between blood-brain barrier dysfunction and cognitive decline and might accelerate Alzheimer’s disease progression.Astrocytes are the most abundant glial cells in the central nervous system with important roles in the structural and functional maintenance of the blood-brain barrier.For example,astrocytic cove rage around endothelial cells with perivascular endfeet and secretion of homeostatic soluble factors are two major underlying mechanisms of astrocytic physiological functions.Astrocyte activation is often observed in Alzheimer’s disease patients,with astrocytes expressing a high level of glial fibrillary acid protein detected around amyloid-beta plaque with the elevated phagocytic ability for amyloid-beta.Structural alte rations in Alzheimer’s disease astrocytes including swollen endfeet,somata shrinkage and possess loss contribute to disruption in vascular integrity at capillary and arte rioles levels.In addition,Alzheimer’s disease astrocytes are skewed into proinflammatory and oxidative profiles with increased secretions of vasoactive mediators inducing endothelial junction disruption and immune cell infiltration.In this review,we summarize the findings of existing literature on the relevance of astrocyte alte ration in response to amyloid pathology in the context of blood-brain barrier dysfunction.First,we briefly describe the physiological roles of astrocytes in blood-brain barrier maintenance.Then,we review the clinical evidence of astrocyte pathology in Alzheimer’s disease patients and the preclinical evidence in animal and cellular models.We further discuss the structural changes of blood-brain barrier that correlates with Alzheimer’s disease astrocyte.Finally,we evaluate the roles of soluble factors secreted by Alzheimer’s disease astrocytes,providing potential molecular mechanisms underlying blood-brain barrier modulation.We conclude with a perspective on investigating the therapeutic potential of targeting astrocytes for blood-brain barrier protection in Alzheimer’s disease.展开更多
Astrocytes are important cellular centers of cholesterol synthesis and metabolism that help maintain normal physiological function at the organism level.Spinal cord injury results in aberrant cholesterol metabolism by...Astrocytes are important cellular centers of cholesterol synthesis and metabolism that help maintain normal physiological function at the organism level.Spinal cord injury results in aberrant cholesterol metabolism by astrocytes and excessive production of oxysterols,which have profound effects on neuropathology.25-Hydroxycholesterol(25-HC),the main product of the membrane-associated enzyme cholesterol-25-hydroxylase(CH25H),plays important roles in mediating neuroinflammation.However,whether the abnormal astrocyte cholesterol metabolism induced by spinal cord injury contributes to the production of 25-HC,as well as the resulting pathological effects,remain unclear.In the present study,spinal cord injury-induced activation of thrombin was found to increase astrocyte CH25H expression.A protease-activated receptor 1 inhibitor was able to attenuate this effect in vitro and in vivo.In cultured primary astrocytes,thrombin interacted with protease-activated receptor 1,mainly through activation of the mitogen-activated protein kinase/nuclear factor-kappa B signaling pathway.Conditioned culture medium from astrocytes in which ch25h expression had been knocked down by siRNA reduced macrophage migration.Finally,injection of the protease activated receptor 1 inhibitor SCH79797 into rat neural sheaths following spinal cord injury reduced migration of microglia/macrophages to the injured site and largely restored motor function.Our results demonstrate a novel regulatory mechanism for thrombin-regulated cholesterol metabolism in astrocytes that could be used to develop anti-inflammatory drugs to treat patients with spinal cord injury.展开更多
The adult cortex has long been regarded as non-neurogenic.Whether injury can induce neurogenesis in the adult cortex is still controversial.Here,we report that focal ischemia stimulates a transient wave of local neuro...The adult cortex has long been regarded as non-neurogenic.Whether injury can induce neurogenesis in the adult cortex is still controversial.Here,we report that focal ischemia stimulates a transient wave of local neurogenesis.Using 5′-bromo-2′-deoxyuridine labeling,we demonstrated a rapid generation of doublecortin-positive neuroblasts that died quickly in mouse cerebral cortex following ischemia.Nestin-Cre^(ER)-based cell ablation and fate mapping showed a small contribution of neuroblasts by subventricular zone neural stem cells.Using a mini-photothrombotic ischemia mouse model and retrovirus expressing green fluorescent protein labeling,we observed maturation of locally generated new neurons.Furthermore,fate tracing analyses using PDGFRα-,GFAP-,and Sox2-Cre^(ER) mice showed a transient wave of neuroblast generation in mild ischemic cortex and identified that Sox2-positive astrocytes were the major neurogenic cells in adult cortex.In addition,a similar upregulation of Sox2 and appearance of neuroblasts were observed in the focal ischemic cortex of Macaca mulatta.Our findings demonstrated a transient neurogenic response of Sox2-positive astrocytes in ischemic cortex,which suggests the possibility of inducing neuronal regeneration by amplifying this intrinsic response in the future.展开更多
Recent studies have shown that microglia/macrophages and astrocytes can mediate synaptic phagocytosis through the MER proto-oncokinase in developmental or stroke models,but it is unclear whether the same mechanism is ...Recent studies have shown that microglia/macrophages and astrocytes can mediate synaptic phagocytosis through the MER proto-oncokinase in developmental or stroke models,but it is unclear whether the same mechanism is also active in traumatic brain injury.In this study,we established a mouse model of traumatic brain injury and found that both microglia/macrophages and astrocytes phagocytosed synapses and expression of the MER proto-oncokinase increased 14 days after injury.Specific knockout of MER in microglia/macrophages or astrocytes markedly reduced injury volume and greatly improved neurobehavioral function.In addition,in both microglia/macrophages-specific and astrocytes-specific MER knock-out mice,the number of microglia/macrophage and astrocyte phagocytosing synapses was markedly decreased,and the total number of dendritic spines was increased.Our study suggested that MER proto-oncokinase expression in microglia/macrophages and astrocytes may play an important role in synaptic phagocytosis,and inhibiting this process could be a new strategy for treating traumatic brain injury.展开更多
Transplantation of neural stem cells(NSCs) can protect neurons in animal stroke models;however, their low rates of survival and neuronal differentiation limit their clinical application. Glial niches, an important loc...Transplantation of neural stem cells(NSCs) can protect neurons in animal stroke models;however, their low rates of survival and neuronal differentiation limit their clinical application. Glial niches, an important location of neural stem cells, regulate survival, proliferation and differentiation of neural stem cells. However, the effects of activated glial cells on neural stem cells remain unclear. In the present study, we explored the effects of activated astrocytes and microglia on neural stem cells in vitro stroke models. We also investigated the effects of combined transplantation of neural stem cells and glial cells after stroke in rats. In a Transwell co-culture system, primary cultured astrocytes, microglia or mixed glial cells were exposed to glutamate or H_2O_2 and then seeded in the upper inserts, while primary neural stem cells were seeded in the lower uncoated wells and cultured for 7 days. Our results showed that microglia were conducive to neurosphere formation and had no effects on apoptosis within neurospheres, while astrocytes and mixed glial cells were conducive to neurosphere differentiation and reduced apoptosis within neurospheres, regardless of their pretreatment. In contrast, microglia and astrocytes induced neuronal differentiation of neural stem cells in differentiation medium, regardless of their pretreatment, with an exception of astrocytes pretreated with H_2O_2. Rat models of ischemic stroke were established by occlusion of the middle cerebral artery. Three days later, 5 × 10~5 neural stem cells with microglia or astrocytes were injected into the right lateral ventricle. Neural stem cell/astrocyte-treated rats displayed better improvement of neurological deficits than neural stem cell only-treated rats at 4 days after cell transplantation. Moreover, neural stem cell/microglia-, and neural stem cell/astrocyte-treated rats showed a significant decrease in ischemic volume compared with neural stem celltreated rats. These findings indicate that microglia and astrocytes exert different effects on neural stem cells, and that co-transplantation of neural stem cells and astrocytes is more conducive to the recovery of neurological impairment in rats with ischemic stroke. The study was approved by the Animal Ethics Committee of Tongji University School of Medicine, China(approval No. 2010-TJAA08220401) in 2010.展开更多
High mobility group box 1(HMGB1) interacts with pattern-recognition receptors of immune cells to activate the inflammatory response. Astrocytes play a positive role in the inflammatory response of the central nervous ...High mobility group box 1(HMGB1) interacts with pattern-recognition receptors of immune cells to activate the inflammatory response. Astrocytes play a positive role in the inflammatory response of the central nervous system by expressing a broad range of patternrecognition receptors. However, the underlying relationship between HMGB1 and the inflammatory reaction of astrocytes remains unclear. In this study, we established rat models of spinal cord injury via laminectomy at the T8–10 level, and the injured spinal cord was subjected to transcriptome sequencing. Our results showed that the HMGB1/Toll-like receptor 4(TLR4) axis was involved in the activation of astrocyte inflammatory response through regulation of cyclooxygenase 2(COX2)/prostaglandin E2(PGE2) signaling. Both TLR4 and COX2 were distributed in astrocytes and showed elevated protein levels following spinal cord injury. Stimulation of primary astrocytes with recombinant HMGB1 showed that COX2 and microsomal PGE synthase(mPGES)-1, rather than COX1, mPGES-2, or cytosolic PGE synthase, were significantly upregulated. Accordingly, PGE2 production in astrocytes was remarkably increased in response to recombinant HMGB1 challenges. Pharmacologic blockade of TLR2/4 attenuated HMGB1-mediated activation of the COX2/PGE2 pathway. Interestingly, HMGB1 did not impact the production of tumor necrosis factor-α or interleukin-1β in astrocytes. Our results suggest that HMGB1 mediates the astrocyte inflammatory response through regulating the COX2/PGE2 signaling pathway. The study was approved by the Laboratory Animal Ethics Committee of Nantong University, China(approval No. 20181204-001) on December 4, 2018.展开更多
The principal pathology of Alzheimer's disease includes neuronal extracellular deposition of amyloid-beta peptides and formation of senile pl aques,which in turn induce neuroinflammation in the brain.Triptolide,a ...The principal pathology of Alzheimer's disease includes neuronal extracellular deposition of amyloid-beta peptides and formation of senile pl aques,which in turn induce neuroinflammation in the brain.Triptolide,a natural extract from the vine-like herb Tripterygium wilfordii Hook F,has potent anti-inflammatory and immunosuppressive efficacy.Therefore,we determined if triptolide can inhibit activation and proliferation of microglial cells and astrocytes in the APP/PS1 double transgenic mouse model of Alzheimer's disease.We used 1 or 5 μg/kg/d triptolide to treat APP/PS1 double transgenic mice(aged 4–4.5 months) for 45 days.Unbiased stereology analysis found that triptolide dose-dependently reduced the total number of microglial cells,and transformed microglial cells into the resting state.Further,triptolide(5 μg/kg/d) also reduced the total number of hippocampal astrocytes.Our in vivo test results indicate that triptolide suppresses activation and proliferation of microglial cells and astrocytes in the hippocampus of APP/PS1 double transgenic mice with Alzheimer's disease.展开更多
After spinal cord injury(SCI),astrocytes gradually migrate to and surround the lesion,depositing chondroitin sulfate proteoglycan-rich extracellular matrix and forming astrocytic scar,which limits the spread of inflam...After spinal cord injury(SCI),astrocytes gradually migrate to and surround the lesion,depositing chondroitin sulfate proteoglycan-rich extracellular matrix and forming astrocytic scar,which limits the spread of inflammation but hinders axon regeneration.Meanwhile,microglia gradually accumulate at the lesion border to form microglial scar and can polarize to generate a pro-inflammatory M1 phenotype or an anti-inflammatory M2 phenotype.However,the effect of microglia polarization on astrocytes is unclear.Here,we found that both microglia(CX3 CR1^(+))and astrocytes(GFAP^(+))gathered at the lesion border at 14 days post-injury(dpi).The microglia accumulated along the inner border of and in direct contact with the astrocytes.M1-type microglia(i NOS^(+)CX3 CR1^(+))were primarily observed at 3 and 7 dpi,while M2-type microglia(Arg1^(+)CX3 CR1^(+))were present at larger numbers at 7 and 14 dpi.Transforming growth factor-β1(TGFβ1)was highly expressed in M1 microglia in vitro,consistent with strong expression of TGFβ1 by microglia in vivo at 3 and 7 dpi,when they primarily exhibited an M1 phenotype.Furthermore,conditioned media from M1-type microglia induced astrocytes to secrete chondroitin sulfate proteoglycan in vitro.This effect was eliminated by knocking down sex-determining region Y-box 9(SOX9)in astrocytes and could not be reversed by treatment with TGFβ1.Taken together,our results suggest that microglia undergo M1 polarization and express high levels of TGFβ1 at 3 and 7 dpi,and that M1-type microglia induce astrocytes to deposit chondroitin sulfate proteoglycan via the TGFβ1/SOX9 pathway.The study was approved by the Institutional Animal Care and Use Committee of Anhui Medical University,China(approval No.LLSC20160052)on March 1,2016.展开更多
Ilexonin A is a compound isolated from the root of Ilex pubescens,a traditional Chinese medicine.Ilexonin A has been shown to play a neuroprotective role by regulating the activation of astrocytes and microglia in the...Ilexonin A is a compound isolated from the root of Ilex pubescens,a traditional Chinese medicine.Ilexonin A has been shown to play a neuroprotective role by regulating the activation of astrocytes and microglia in the peri-infarct area after ischemia.However,the effects of ilexonin A on astrocytes and microglia in the infarct-free region of the hippocampal CA1 region remain unclear.Focal cerebral ischemia models were established by 2-hour occlusion of the middle cerebral artery in rats.Ilexonin A(20,40 or 80 mg/kg)was administered immediately after ischemia/reperfusion.The astrocyte marker glial fibrillary acidic protein,microglia marker Iba-1,neural stem cell marker nestin and inflammation markers were detected by immunohistochemistry and western blot assay.Expression levels of tumor necrosis factor-αand interleukin 1βwere determined by enzyme linked immunosorbent assay in the hippocampal CA1 tissue.Astrocytes were activated immediately in progressively increasing numbers from 1,3,to 7 days post-ischemia/reperfusion.The number of activated astrocytes further increased in the hippocampal CA1 region after treatment with ilexonin A.Microglial cells remained quiescent after ischemia/reperfusion,but became activated after treatment with ilexonin A.Ilexonin A enhanced nestin expression and reduced the expression of tumor necrosis factor-αand interleukin 1βin the hippocampus post-ischemia/reperfusion.The results of the present study suggest that ilexonin A has a neuroprotective effect in the hippocampus after ischemia/reperfusion,probably through regulating astrocytes and microglia activation,promoting neuronal stem cell proliferation and reducing the levels of pro-inflammatory factors.This study was approved by the Animal Ethics Committee of the Fujian Medical University Union Hospital,China.展开更多
Astrocytes play multifaceted and vital roles in maintaining neurophysiological function of the central nervous system by regulating homeostasis, increasing synaptic plasticity, and sustaining neuroprotective effects. ...Astrocytes play multifaceted and vital roles in maintaining neurophysiological function of the central nervous system by regulating homeostasis, increasing synaptic plasticity, and sustaining neuroprotective effects. Astrocytes become activated as a result of inflammatory responses during the progression of pathological changes associated with neurodegenerative disorders. Reactive astrocytes(neurotoxic A1 and neuroprotective A2) are triggered during disease progression and pathogenesis due to neuroinflammation and ischemia. However, only a limited body of literature describes morphological and functional changes of astrocytes during the progression of neurodegenerative diseases. The present review investigated the detrimental and beneficial roles of astrocytes in neurodegenerative diseases reported in recent studies, as these cells have promising therapeutic potential and offer new approaches for treatment of neurodegenerative diseases.展开更多
Multiple protocols have been devised to generate cerebral organoids that recapitulate features of the developing human brain, including the presence of a large, multi-layered, cortical-like neuronal zone. However, the...Multiple protocols have been devised to generate cerebral organoids that recapitulate features of the developing human brain, including the presence of a large, multi-layered, cortical-like neuronal zone. However, the central question is whether these organoids truly present mature, functional neurons and astrocytes, which may qualify the system for in-depth molecular neuroscience studies focused at neuronal and synaptic functions. Here, we demonstrate that cerebral organoids derived under optimal differentiation conditions exhibit mature, fully functional neurons and astrocytes, as validated by immunohistological, gene expression, and electrophysiological, analyses. Neurons in cerebral organoids showed gene expression profiles and electrophysiological properties similar to those reported for fetal human brain. These important findings indicate that cerebral organoids recapitulate the developing human brain and may enhance use of cerebral organoids in modeling human brain development or investigating neural deficits that underlie neurodevelopmental and neuropsychiatric conditions, such as autism or intellectual disorders.展开更多
基金supported by the National Natural Science Foundation of China,No.82071278(to PY)Outstanding Young Medical Talents Project of Changhai Hospital,No.2021JCSQ03(to PY)+1 种基金Shanghai Sailing Program,No.20YF1448000(to XZ)Medical Health Science and Technology Project of Zhoushan City,No.2022JRC01(to HL).
文摘Astrocytes are the most abundant glial cells in the central nervous system;they participate in crucial biological processes,maintain brain structure,and regulate nervous system function.Exosomes are cell-derived extracellular vesicles containing various bioactive molecules including proteins,peptides,nucleotides,and lipids secreted from their cellular sources.Increasing evidence shows that exosomes participate in a communication network in the nervous system,in which astrocyte-derived exosomes play important roles.In this review,we have summarized the effects of exosomes targeting astrocytes and the astrocyte-derived exosomes targeting other cell types in the central nervous system.We also discuss the potential research directions of the exosome-based communication network in the nervous system.The exosome-based intercellular communication focused on astrocytes is of great significance to the biological and/or pathological processes in different conditions in the brain.New strategies may be developed for the diagnosis and treatment of neurological disorders by focusing on astrocytes as the central cells and utilizing exosomes as communication mediators.
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.
基金supported by the National Natural Science Foundation of China,No.82071418the Natural Science Foundation of Fujian Province,No.2020J01612 (both to EH)。
文摘In situ direct reprogramming technology can directly convert endogenous glial cells into functional neurons in vivo for central nervous system repair. Polypyrimidine tract-binding protein 1(PTB) knockdown has been shown to reprogram astrocytes to functional neurons in situ. In this study, we used AAV-PHP.e B-GFAP-sh PTB to knockdown PTB in a mouse model of ischemic stroke induced by endothelin-1, and investigated the effects of GFAP-sh PTB-mediated direct reprogramming to neurons. Our results showed that in the mouse model of ischemic stroke, PTB knockdown effectively reprogrammed GFAP-positive cells to neurons in ischemic foci, restored neural tissue structure, reduced inflammatory response, and improved behavioral function. These findings validate the effectiveness of in situ transdifferentiation of astrocytes, and suggest that the approach may be a promising strategy for stroke treatment.
基金supported by fellowship to a grant from CRT Foundation,No.1393-2017(to LT)grants from the Fondazione Cariplo,Nos.2013-0795(to AAG),2014-1094(to DL)grants from The Universitàdel Piemonte Orientale,Nos.FAR-2016(to DL),FAR-2019(to DL)。
文摘Alzheimer's disease(AD)is characterized by complex etiology,long-lasting pathogenesis,and celltype-specific alterations.Currently,there is no cure for AD,emphasizing the urgent need for a comprehensive understanding of cell-specific pathology.Astrocytes,principal homeostatic cells of the central nervous system,are key players in the pathogenesis of neurodegenerative diseases,including AD.Cellular models greatly facilitate the investigation of cell-specific pathological alterations and the dissection of molecular mechanisms and pathways.Tumor-derived and immortalized astrocytic cell lines,alongside the emerging technology of adult induced pluripotent stem cells,are widely used to study cellular dysfunction in AD.Surprisingly,no stable cell lines were available from genetic mouse AD models.Recently,we established immortalized hippocampal astroglial cell lines from amyloid-βprecursor protein/presenilin-1/Tau triple-transgenic(3xTg)-AD mice(denominated as wild type(WT)-and 3Tg-iAstro cells)using retrovirus-mediated transduction of simian virus 40 large T-antigen and propagation without clonal selection,thereby maintaining natural heterogeneity of primary cultures.Several groups have successfully used 3Tg-iAstro cells for single-cell and omics approaches to study astrocytic AD-related alterations of calcium signaling,mitochondrial dysfunctions,disproteostasis,altered homeostatic and signaling support to neurons,and blood-brain barrier models.Here we provide a comparative overview of the most used models to study astrocytes in vitro,such as primary culture,tumor-derived cell lines,immortalized astroglial cell lines,and induced pluripotent stem cell-derived astrocytes.We conclude that immortalized WT-and 3Tg-iAstro cells provide a noncompetitive but complementary,low-cost,easy-to-handle,and versatile cellular model for dissection of astrocyte-specific AD-related alterations and preclinical drug discovery.
基金supported by the Natural Science Foundation of Guangdong Province,No.2020A1515010090(to ZLZ)the Science and Technology Project Foundation of Guangzhou City,No.202002030004(to HZ).
文摘Astrocytes and microglia play an orchestrated role following spinal cord injury;however,the molecular mechanisms through which microglia regulate astrocytes after spinal cord injury are not yet fully understood.Herein,microglia were pharmacologically depleted and the effects on the astrocytic response were examined.We further explored the potential mechanisms involving the signal transducers and activators of transcription 3(STAT3)pathway.For in vivo experiments,we constructed a contusion spinal cord injury model in C57BL/6 mice.To deplete microglia,all mice were treated with colony-stimulating factor 1 receptor inhibitor PLX3397,starting 2 weeks prior to surgery until they were sacrificed.Cell proliferation was examined by 5-ethynyl-2-deoxyuridine(EdU)and three pivotal inflammatory cytokines were detected by a specific Bio-Plex Pro^(TM) Reagent Kit.Locomotor function,neuroinflammation,astrocyte activation and phosphorylated STAT3(pSTAT3,a maker of activation of STAT3 signaling)levels were determined.For in vitro experiments,a microglia and astrocyte coculture system was established,and the small molecule STA21,which blocks STAT3 activation,was applied to investigate whether STAT3 signaling is involved in mediating astrocyte proliferation induced by microglia.PLX3397 administration disrupted glial scar formation,increased inflammatory spillover,induced diffuse tissue damage and impaired functional recovery after spinal cord injury.Microglial depletion markedly reduced EdU+proliferating cells,especially proliferating astrocytes at 7 days after spinal cord injury.RNA sequencing analysis showed that the JAK/STAT3 pathway was downregulated in mice treated with PLX3397.Double immunofluorescence staining confirmed that PLX3397 significantly decreased STAT3 expression in astrocytes.Importantly,in vitro coculture of astrocytes and microglia showed that microglia-induced astrocyte proliferation was abolished by STA21 administration.These findings suggest that microglial depletion impaired astrocyte proliferation and astrocytic scar formation,and induced inflammatory diffusion partly by inhibiting STAT3 phosphorylation in astrocytes following spinal cord injury.
基金supported by National Science Foundation grants Division of Mathmatical Science1720487 and 1720452(to DL)。
文摘Astrocytes,a subtype of glial cells,are star-shaped cells that are involved in the homeostasis and blood flow control of the central nervous system(CNS).They are known to provide structural and functional support to neurons,including the regulation of neuronal activation through extracellular ion concentrations,the regulation of energy dynamics in the brain through the transfer of lactate to neurons,and the modulation of synaptic transmission via the release of neurotransmitters such as glutamate and adenosine triphosphate.In addition,astrocytes play a critical role in neuronal reconstruction after brain injury,including neurogenesis,synaptogenesis,angiogenesis,repair of the blood-brain barrier,and glial scar formation after traumatic brain injury(Zhou et al.,2020).
基金supported by grants from the National Natural Science Foundation of China, Nos. 81930031 (to JNZ), 81720108015 (to JNZ), 81901525 (to SZ), 82101440 (to DDS), 81801234 (to YZ) and 82071389 (to GLY)the Natural Science Foundation of Tianjin, Nos. 20JCQNJC01270 (to JWW), 20JCQNJC00460 (to GLY), 18JCQNJC81000 (to HTR)+4 种基金Scientific Research Project of Tianjin Education Commission (Natural Science), No. 2018KJ052 (to ZWZ)Tianjin Health and Health Committee Science and Technology Project, No. QN20015 (to JWW)the Science & Technology Development Fund of Tianjin Education Commission for Higher Education, No. 2016YD02 (to YW)Tianjin Key Science and Technology Projects of Innovative Drugs and Medical Devices, No. 19ZXYXSY00070 (to YW)the Clinical Research Fundation of Tianjin Medical University, No. 2018kylc002 (to YW)
文摘Neuroinflammation and the NACHT,LRR,and PYD domains-containing protein 3 inflammasome play crucial roles in secondary tissue damage following an initial insult in patients with traumatic brain injury(TBI).Maraviroc,a C-C chemokine receptor type 5 antagonist,has been viewed as a new therapeutic strategy for many neuroinflammatory diseases.We studied the effect of maraviroc on TBI-induced neuroinflammation.A moderate-TBI mouse model was subjected to a controlled cortical impact device.Maraviroc or vehicle was injected intraperitoneally 1 hour after TBI and then once per day for 3 consecutive days.Western blot,immunohistochemistry,and TUNEL(terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling)analyses were performed to evaluate the molecular mechanisms of maraviroc at 3 days post-TBI.Our results suggest that maraviroc administration reduced NACHT,LRR,and PYD domains-containing protein 3 inflammasome activation,modulated microglial polarization from M1 to M2,decreased neutrophil and macrophage infiltration,and inhibited the release of inflammatory factors after TBI.Moreover,maraviroc treatment decreased the activation of neurotoxic reactive astrocytes,which,in turn,exacerbated neuronal cell death.Additionally,we confirmed the neuroprotective effect of maraviroc using the modified neurological severity score,rotarod test,Morris water maze test,and lesion volume measurements.In summary,our findings indicate that maraviroc might be a desirable pharmacotherapeutic strategy for TBI,and C-C chemokine receptor type 5 might be a promising pharmacotherapeutic target to improve recovery after TBI.
基金supported by the National Natural Sclence Foundation of China in 2021No.82171213+1 种基金the Natural Science Foundation of Fujian Province in 2019No.2019J01289 (both to DSL)
文摘The trigeminal root entry zone is the zone at which the myelination switches from peripheral Schwann cells to central oligodendrocytes.Its special anatomical and physiological structure renders it susceptible to nerve injury.The etiology of most primary trigeminal neuralgia is closely related to microvascular compression of the trigeminal root entry zone.This study aimed to develop an efficient in vitro model mimicking the glial environment of trigeminal root entry zone as a tool to investigate the effects of glial cell line-derived neurotrophic factor and brain-derived neurotrophic factor on the structural and functional integrity of trigeminal root entry zone and modulation of cellular interactions.Primary astrocytes and Schwann cells isolated from trigeminal root entry zone of postnatal rats were inoculated into a two-well silicon culture insert to mimic the trigeminal root entry zone microenvironment and treated with glial cell line-derived neurotrophic factor and brain-derived neurotrophic factor.In monoculture,glial cell line-derived neurotrophic factor promoted the migration of Schwann cells,but it did not have effects on the migration of astrocytes.In the co-culture system,glial cell line-derived neurotrophic factor promoted the bidirectional migration of astrocytes and Schwann cells.Brain-derived neurotrophic factor markedly promoted the activation and migration of astrocytes.However,in the co-culture system,brain-derived neurotrophic factor inhibited the migration of astrocytes and Schwann cells to a certain degree.These findings suggest that glial cell line-derived neurotrophic factor and brain-derived neurotrophic factor are involved in the regulation of the astrocyte-Schwann cell interaction in the co-culture system derived from the trigeminal root entry zone.This system can be used as a cell model to study the mechanism of glial dysregulation associated with trigeminal nerve injury and possible therapeutic interventions.
文摘Astrocytes are key cells in the central nervous system.They are involved in many important functions under physiological and pathological conditions.As part of neuroglia,they have been recognised as cellular elements in their own right.The name astrocyte was first proposed by Mihaly von Lenhossek in 1895 because of the finely branched processes and star-like appearance of these particular cells.As early as the late 19th and early 20th centuries,Ramon y Cajal and Camillo Golgi had noted that although astrocytes have stellate features,their morphology is extremely diverse.Modern research has confirmed the morphological diversity of astrocytes both in vitro and in vivo and their complex,specific,and important roles in the central nervous system.In this review,the functions of astrocytes and their roles are described.
基金supported by the Science and Technology Development Fund (Macao SAR)(120015/2019/ASC,0023/2020/AFJ,0035/2020/AGJ)the University of Macao Research Grant (MYRG2022-00248-ICMS)(all to MPMH)。
文摘Blood-brain barrier disruption occurs in the early stages of Alzheimer’s disease.Recent studies indicate a link between blood-brain barrier dysfunction and cognitive decline and might accelerate Alzheimer’s disease progression.Astrocytes are the most abundant glial cells in the central nervous system with important roles in the structural and functional maintenance of the blood-brain barrier.For example,astrocytic cove rage around endothelial cells with perivascular endfeet and secretion of homeostatic soluble factors are two major underlying mechanisms of astrocytic physiological functions.Astrocyte activation is often observed in Alzheimer’s disease patients,with astrocytes expressing a high level of glial fibrillary acid protein detected around amyloid-beta plaque with the elevated phagocytic ability for amyloid-beta.Structural alte rations in Alzheimer’s disease astrocytes including swollen endfeet,somata shrinkage and possess loss contribute to disruption in vascular integrity at capillary and arte rioles levels.In addition,Alzheimer’s disease astrocytes are skewed into proinflammatory and oxidative profiles with increased secretions of vasoactive mediators inducing endothelial junction disruption and immune cell infiltration.In this review,we summarize the findings of existing literature on the relevance of astrocyte alte ration in response to amyloid pathology in the context of blood-brain barrier dysfunction.First,we briefly describe the physiological roles of astrocytes in blood-brain barrier maintenance.Then,we review the clinical evidence of astrocyte pathology in Alzheimer’s disease patients and the preclinical evidence in animal and cellular models.We further discuss the structural changes of blood-brain barrier that correlates with Alzheimer’s disease astrocyte.Finally,we evaluate the roles of soluble factors secreted by Alzheimer’s disease astrocytes,providing potential molecular mechanisms underlying blood-brain barrier modulation.We conclude with a perspective on investigating the therapeutic potential of targeting astrocytes for blood-brain barrier protection in Alzheimer’s disease.
基金supported by the National Natural Science Foundation of ChinaNo.81971826 (to AG)+5 种基金the China Postdoctoral Science FoundationNo.2020M681 689 (to YH)the Scientific Research Project of The Health Commission of Jiangsu ProvinceNo.ZDB2020003 (to AG)the Basic Scientific Research Projects of NantongNo.JC2020041 (to YH)
文摘Astrocytes are important cellular centers of cholesterol synthesis and metabolism that help maintain normal physiological function at the organism level.Spinal cord injury results in aberrant cholesterol metabolism by astrocytes and excessive production of oxysterols,which have profound effects on neuropathology.25-Hydroxycholesterol(25-HC),the main product of the membrane-associated enzyme cholesterol-25-hydroxylase(CH25H),plays important roles in mediating neuroinflammation.However,whether the abnormal astrocyte cholesterol metabolism induced by spinal cord injury contributes to the production of 25-HC,as well as the resulting pathological effects,remain unclear.In the present study,spinal cord injury-induced activation of thrombin was found to increase astrocyte CH25H expression.A protease-activated receptor 1 inhibitor was able to attenuate this effect in vitro and in vivo.In cultured primary astrocytes,thrombin interacted with protease-activated receptor 1,mainly through activation of the mitogen-activated protein kinase/nuclear factor-kappa B signaling pathway.Conditioned culture medium from astrocytes in which ch25h expression had been knocked down by siRNA reduced macrophage migration.Finally,injection of the protease activated receptor 1 inhibitor SCH79797 into rat neural sheaths following spinal cord injury reduced migration of microglia/macrophages to the injured site and largely restored motor function.Our results demonstrate a novel regulatory mechanism for thrombin-regulated cholesterol metabolism in astrocytes that could be used to develop anti-inflammatory drugs to treat patients with spinal cord injury.
基金supported by the National Natural Science Foundation of China,Nos.82171346(to YZW)82171269(to JLY)+1 种基金82171471(to HF)Beijing Nova Program,No.Z201100006820076(to JLY).
文摘The adult cortex has long been regarded as non-neurogenic.Whether injury can induce neurogenesis in the adult cortex is still controversial.Here,we report that focal ischemia stimulates a transient wave of local neurogenesis.Using 5′-bromo-2′-deoxyuridine labeling,we demonstrated a rapid generation of doublecortin-positive neuroblasts that died quickly in mouse cerebral cortex following ischemia.Nestin-Cre^(ER)-based cell ablation and fate mapping showed a small contribution of neuroblasts by subventricular zone neural stem cells.Using a mini-photothrombotic ischemia mouse model and retrovirus expressing green fluorescent protein labeling,we observed maturation of locally generated new neurons.Furthermore,fate tracing analyses using PDGFRα-,GFAP-,and Sox2-Cre^(ER) mice showed a transient wave of neuroblast generation in mild ischemic cortex and identified that Sox2-positive astrocytes were the major neurogenic cells in adult cortex.In addition,a similar upregulation of Sox2 and appearance of neuroblasts were observed in the focal ischemic cortex of Macaca mulatta.Our findings demonstrated a transient neurogenic response of Sox2-positive astrocytes in ischemic cortex,which suggests the possibility of inducing neuronal regeneration by amplifying this intrinsic response in the future.
基金supported by the National Key R&D Program of China,No.2019YFA0112000(to YHT)the National Natural Science Foundation of China,Nos.82071284(to YHT),81974179(to ZJZ)+4 种基金Shanghai Rising-Star Program,No.21QA1405200(to YHT)the Scientific Research and Innovation Program of Shanghai Education Commission,No.2019-01-07-00-02-E00064(to GYY)Scientific and Technological Innovation Act Program of Shanghai Science and Technology Commission,No.20JC1411900(to GYY)the Notional Research Foundation of Korea,Nos.2020M3E5D9079912(to WSC),2021R1A2C3005704(to WSC),2022M3E5E8081188(to WSC)the Korea Health Technology R&D Project,No.HU20C0290(to WSC)。
文摘Recent studies have shown that microglia/macrophages and astrocytes can mediate synaptic phagocytosis through the MER proto-oncokinase in developmental or stroke models,but it is unclear whether the same mechanism is also active in traumatic brain injury.In this study,we established a mouse model of traumatic brain injury and found that both microglia/macrophages and astrocytes phagocytosed synapses and expression of the MER proto-oncokinase increased 14 days after injury.Specific knockout of MER in microglia/macrophages or astrocytes markedly reduced injury volume and greatly improved neurobehavioral function.In addition,in both microglia/macrophages-specific and astrocytes-specific MER knock-out mice,the number of microglia/macrophage and astrocyte phagocytosing synapses was markedly decreased,and the total number of dendritic spines was increased.Our study suggested that MER proto-oncokinase expression in microglia/macrophages and astrocytes may play an important role in synaptic phagocytosis,and inhibiting this process could be a new strategy for treating traumatic brain injury.
基金supported by the National Natural Science Foundation of China,Nos.81371213,81070987,30971531grants from the Ministry of Science and Technology of China,Nos.2010CB945600,2010CB945601(all to QLY)。
文摘Transplantation of neural stem cells(NSCs) can protect neurons in animal stroke models;however, their low rates of survival and neuronal differentiation limit their clinical application. Glial niches, an important location of neural stem cells, regulate survival, proliferation and differentiation of neural stem cells. However, the effects of activated glial cells on neural stem cells remain unclear. In the present study, we explored the effects of activated astrocytes and microglia on neural stem cells in vitro stroke models. We also investigated the effects of combined transplantation of neural stem cells and glial cells after stroke in rats. In a Transwell co-culture system, primary cultured astrocytes, microglia or mixed glial cells were exposed to glutamate or H_2O_2 and then seeded in the upper inserts, while primary neural stem cells were seeded in the lower uncoated wells and cultured for 7 days. Our results showed that microglia were conducive to neurosphere formation and had no effects on apoptosis within neurospheres, while astrocytes and mixed glial cells were conducive to neurosphere differentiation and reduced apoptosis within neurospheres, regardless of their pretreatment. In contrast, microglia and astrocytes induced neuronal differentiation of neural stem cells in differentiation medium, regardless of their pretreatment, with an exception of astrocytes pretreated with H_2O_2. Rat models of ischemic stroke were established by occlusion of the middle cerebral artery. Three days later, 5 × 10~5 neural stem cells with microglia or astrocytes were injected into the right lateral ventricle. Neural stem cell/astrocyte-treated rats displayed better improvement of neurological deficits than neural stem cell only-treated rats at 4 days after cell transplantation. Moreover, neural stem cell/microglia-, and neural stem cell/astrocyte-treated rats showed a significant decrease in ischemic volume compared with neural stem celltreated rats. These findings indicate that microglia and astrocytes exert different effects on neural stem cells, and that co-transplantation of neural stem cells and astrocytes is more conducive to the recovery of neurological impairment in rats with ischemic stroke. The study was approved by the Animal Ethics Committee of Tongji University School of Medicine, China(approval No. 2010-TJAA08220401) in 2010.
基金supported by the National Key Research and Development Program of China,No.2018YFC1105603(to YJunW)the National Natural Science Foundation of China,No.31871211(to YJunW)+2 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)(to YJunW)the China Postdoctoral Science Foundation,No.2020M681689(to YMH)the Basic Scientific Research Projects of Nantong of China,No.JC2018065(to HHS)。
文摘High mobility group box 1(HMGB1) interacts with pattern-recognition receptors of immune cells to activate the inflammatory response. Astrocytes play a positive role in the inflammatory response of the central nervous system by expressing a broad range of patternrecognition receptors. However, the underlying relationship between HMGB1 and the inflammatory reaction of astrocytes remains unclear. In this study, we established rat models of spinal cord injury via laminectomy at the T8–10 level, and the injured spinal cord was subjected to transcriptome sequencing. Our results showed that the HMGB1/Toll-like receptor 4(TLR4) axis was involved in the activation of astrocyte inflammatory response through regulation of cyclooxygenase 2(COX2)/prostaglandin E2(PGE2) signaling. Both TLR4 and COX2 were distributed in astrocytes and showed elevated protein levels following spinal cord injury. Stimulation of primary astrocytes with recombinant HMGB1 showed that COX2 and microsomal PGE synthase(mPGES)-1, rather than COX1, mPGES-2, or cytosolic PGE synthase, were significantly upregulated. Accordingly, PGE2 production in astrocytes was remarkably increased in response to recombinant HMGB1 challenges. Pharmacologic blockade of TLR2/4 attenuated HMGB1-mediated activation of the COX2/PGE2 pathway. Interestingly, HMGB1 did not impact the production of tumor necrosis factor-α or interleukin-1β in astrocytes. Our results suggest that HMGB1 mediates the astrocyte inflammatory response through regulating the COX2/PGE2 signaling pathway. The study was approved by the Laboratory Animal Ethics Committee of Nantong University, China(approval No. 20181204-001) on December 4, 2018.
基金supported by China Postdoctoral Science Foundation,No.2016M590757the Postdoctoral Science Foundation of Xiangya Hospital of Central South University of China,No.20+4 种基金the Hunan Provincial Natural Science Foundation of China,No.2015JJ6010a grant from the Basic Research Program of Science and Technology Commission Foundation of Hunan Province of China,No.2015JC3059the Project Fund of the Department of Education in Hunan Province of China,No.15A023,13C1107the Scientific Research Project Fund of Health Department of Hunan Province of China,No.B2011-071,B2016096a grant from the Construction Program of the Key Discipline in Hunan Province of China
文摘The principal pathology of Alzheimer's disease includes neuronal extracellular deposition of amyloid-beta peptides and formation of senile pl aques,which in turn induce neuroinflammation in the brain.Triptolide,a natural extract from the vine-like herb Tripterygium wilfordii Hook F,has potent anti-inflammatory and immunosuppressive efficacy.Therefore,we determined if triptolide can inhibit activation and proliferation of microglial cells and astrocytes in the APP/PS1 double transgenic mouse model of Alzheimer's disease.We used 1 or 5 μg/kg/d triptolide to treat APP/PS1 double transgenic mice(aged 4–4.5 months) for 45 days.Unbiased stereology analysis found that triptolide dose-dependently reduced the total number of microglial cells,and transformed microglial cells into the resting state.Further,triptolide(5 μg/kg/d) also reduced the total number of hippocampal astrocytes.Our in vivo test results indicate that triptolide suppresses activation and proliferation of microglial cells and astrocytes in the hippocampus of APP/PS1 double transgenic mice with Alzheimer's disease.
基金supported by the National Natural Science Foundation of China,Nos.81801220(to MGZ),81671204(to JHJ)Key Research and Development Projects of Anhui Province of China,No.202004j07020042(to JHJ)。
文摘After spinal cord injury(SCI),astrocytes gradually migrate to and surround the lesion,depositing chondroitin sulfate proteoglycan-rich extracellular matrix and forming astrocytic scar,which limits the spread of inflammation but hinders axon regeneration.Meanwhile,microglia gradually accumulate at the lesion border to form microglial scar and can polarize to generate a pro-inflammatory M1 phenotype or an anti-inflammatory M2 phenotype.However,the effect of microglia polarization on astrocytes is unclear.Here,we found that both microglia(CX3 CR1^(+))and astrocytes(GFAP^(+))gathered at the lesion border at 14 days post-injury(dpi).The microglia accumulated along the inner border of and in direct contact with the astrocytes.M1-type microglia(i NOS^(+)CX3 CR1^(+))were primarily observed at 3 and 7 dpi,while M2-type microglia(Arg1^(+)CX3 CR1^(+))were present at larger numbers at 7 and 14 dpi.Transforming growth factor-β1(TGFβ1)was highly expressed in M1 microglia in vitro,consistent with strong expression of TGFβ1 by microglia in vivo at 3 and 7 dpi,when they primarily exhibited an M1 phenotype.Furthermore,conditioned media from M1-type microglia induced astrocytes to secrete chondroitin sulfate proteoglycan in vitro.This effect was eliminated by knocking down sex-determining region Y-box 9(SOX9)in astrocytes and could not be reversed by treatment with TGFβ1.Taken together,our results suggest that microglia undergo M1 polarization and express high levels of TGFβ1 at 3 and 7 dpi,and that M1-type microglia induce astrocytes to deposit chondroitin sulfate proteoglycan via the TGFβ1/SOX9 pathway.The study was approved by the Institutional Animal Care and Use Committee of Anhui Medical University,China(approval No.LLSC20160052)on March 1,2016.
基金supported by the Natural Science Foundation of Fujian Province of China,No.2014J01327the Program for New Century Excellent Talents in Colleges and Universities of Fujian Province of China,No.NCETFJ-0704the Professorial Academic Development Foundation of Fujian Medical University of China,No.JS09014(all to GYZ)
文摘Ilexonin A is a compound isolated from the root of Ilex pubescens,a traditional Chinese medicine.Ilexonin A has been shown to play a neuroprotective role by regulating the activation of astrocytes and microglia in the peri-infarct area after ischemia.However,the effects of ilexonin A on astrocytes and microglia in the infarct-free region of the hippocampal CA1 region remain unclear.Focal cerebral ischemia models were established by 2-hour occlusion of the middle cerebral artery in rats.Ilexonin A(20,40 or 80 mg/kg)was administered immediately after ischemia/reperfusion.The astrocyte marker glial fibrillary acidic protein,microglia marker Iba-1,neural stem cell marker nestin and inflammation markers were detected by immunohistochemistry and western blot assay.Expression levels of tumor necrosis factor-αand interleukin 1βwere determined by enzyme linked immunosorbent assay in the hippocampal CA1 tissue.Astrocytes were activated immediately in progressively increasing numbers from 1,3,to 7 days post-ischemia/reperfusion.The number of activated astrocytes further increased in the hippocampal CA1 region after treatment with ilexonin A.Microglial cells remained quiescent after ischemia/reperfusion,but became activated after treatment with ilexonin A.Ilexonin A enhanced nestin expression and reduced the expression of tumor necrosis factor-αand interleukin 1βin the hippocampus post-ischemia/reperfusion.The results of the present study suggest that ilexonin A has a neuroprotective effect in the hippocampus after ischemia/reperfusion,probably through regulating astrocytes and microglia activation,promoting neuronal stem cell proliferation and reducing the levels of pro-inflammatory factors.This study was approved by the Animal Ethics Committee of the Fujian Medical University Union Hospital,China.
基金supported partially by the National Natural Science Foundation of China,No.81473577(to CGM)a grant from the Department of Science and Technology of Shanxi Province,China,No.201803D421073(to YQY)and No.201805D111009(to CGM)+2 种基金a grant from Shanxi Applied Basic Research Project,No.201901D211538(to LJS)Datong Bureau of Science and Technology of China,No.2019198(to CGM)Research Project Funds from Shanxi Scholarship Council of China,No.2014-7(to CGM)。
文摘Astrocytes play multifaceted and vital roles in maintaining neurophysiological function of the central nervous system by regulating homeostasis, increasing synaptic plasticity, and sustaining neuroprotective effects. Astrocytes become activated as a result of inflammatory responses during the progression of pathological changes associated with neurodegenerative disorders. Reactive astrocytes(neurotoxic A1 and neuroprotective A2) are triggered during disease progression and pathogenesis due to neuroinflammation and ischemia. However, only a limited body of literature describes morphological and functional changes of astrocytes during the progression of neurodegenerative diseases. The present review investigated the detrimental and beneficial roles of astrocytes in neurodegenerative diseases reported in recent studies, as these cells have promising therapeutic potential and offer new approaches for treatment of neurodegenerative diseases.
文摘Multiple protocols have been devised to generate cerebral organoids that recapitulate features of the developing human brain, including the presence of a large, multi-layered, cortical-like neuronal zone. However, the central question is whether these organoids truly present mature, functional neurons and astrocytes, which may qualify the system for in-depth molecular neuroscience studies focused at neuronal and synaptic functions. Here, we demonstrate that cerebral organoids derived under optimal differentiation conditions exhibit mature, fully functional neurons and astrocytes, as validated by immunohistological, gene expression, and electrophysiological, analyses. Neurons in cerebral organoids showed gene expression profiles and electrophysiological properties similar to those reported for fetal human brain. These important findings indicate that cerebral organoids recapitulate the developing human brain and may enhance use of cerebral organoids in modeling human brain development or investigating neural deficits that underlie neurodevelopmental and neuropsychiatric conditions, such as autism or intellectual disorders.
