Effect of Astrocyte-neuron Coupling Imbalance in Development of Alzheimer's Disease and Intervention Mechanism of Kidney-tonifying and Marrow-filling TCM Prescriptions / 中国实验方剂学杂志

Astrocytes are important nerve cells in the central nervous system （CNS）， which mainly play a key role in nutrition and support. Astrocytes and neurons undergo close energy coupling and substance coupling， which are closely related and interact with each other. In recent years， many studies have shown that the astrocyte-neuron coupling imbalance plays a central role in the occurrence and progression of Alzheimer's disease （AD） and serves as an important therapeutic target receiving increasing attention. According to traditional Chinese medicine （TCM） theory， the main pathogenesis of AD is kidney deficiency and marrow inadequacy， and in clinical medication， kidney-tonifying and marrow-filling TCM prescriptions are often employed with satisfactory results achieved. As reported， many kidney-tonifying and marrow-filling prescriptions exhibit regulatory and protective effects on the imbalance of astrocyte-neuron coupling， suggesting that the effect of kidney-tonifying and marrow-filling prescriptions in treating AD may have some internal relationship with its regulation of the imbalance of astrocyte-neuron coupling. This article reviewed the underlying internal relationship between the imbalance of astrocyte-neuron coupling and the pathogenesis of kidney deficiency and marrow inadequacy in AD and the research progress in the intervention mechanism of TCM for tonifying the kidney and filling the marrow.

Peripheral origin exosomal microRNAs aggravate glymphatic system dysfunction in diabetic cognitive impairment

Cognitive dysfunction is one of the common central nervous systems (CNS) complications of diabetes mellitus, which seriously affects the quality of life of patients and results in a huge economic burden. The glymphatic system dysfunction mediated by aquaporin-4 (AQP4) loss or redistribution in perivascular astrocyte endfeet plays a crucial role in diabetes-induced cognitive impairment (DCI). However, the mechanism of AQP4 loss or redistribution in the diabetic states remains unclear. Accumulating evidence suggests that peripheral insulin resistance target tissues and CNS communication affect brain homeostasis and that exosomal miRNAs are key mediators. Glucose and lipid metabolism disorder is an important pathological feature of diabetes mellitus, and skeletal muscle, liver and adipose tissue are the key target insulin resistance organs. In this review, the changes in exosomal miRNAs induced by peripheral metabolism disorders in diabetes mellitus were systematically reviewed. We focused on exosomal miRNAs that could induce low AQP4 expression and redistribution in perivascular astrocyte endfeet, which could provide an interorgan communication pathway to illustrate the pathogenesis of DCI. Furthermore, the mechanisms of exosome secretion from peripheral insulin resistance target tissue and absorption to the CNS were summarized, which will be beneficial for proposing novel and feasible strategies to optimize DCI prevention and/or treatment in diabetic patients.

Diesel exhaust inhalation exposure induced toxicity on olfactory bulb in mice through inflammatory response mediated by activating glial cells / 环境与职业医学

Background Air pollution is related to the occurrence and development of mental diseases. Olfactory bulb damage might be the potential prodromal symptom and sign of these diseases. The toxicity of diesel exhaust (DE), one of the main sources of air pollution, on olfactory bulb and the underlying mechanisms remain to be elucidated. Objective To explore the toxicity of DE on mouse olfactory bulb and underlying mechanisms. Methods A total of 40 C57BL/6 mice were randomly divided into four groups for exposure to DE by systemic inhalation: control group (filtered air), low exposure group (750 μg·m−3 DE), medium exposure group (1500 μg·m−3 DE), and high exposure group (3000 μg·m−3 DE). The mouse inhalation exposure to DE was performed 1 h per day for 28 d. HE staining was performed to observe pathological changes in mouse olfactory bulb tissue. TUNEL assay was used to observe apop-tosis in olfactory bulb. Kyoto Encyclopedia of Genes and Genomes (KEGG) was exhibited to explore potential mechanisms of olfactory bulb damage associated with DE. Quantitative real-time PCR (qPCR) was used to determine mRNA expression levels of inflammatory factors including tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Immunofluorescence staining was conducted to observed the microglia and astrocyte activation in olfactory bulb. Results The HE staining results showed that the number of periglomerular cells in the glomerular layer of olfactory bulb decreased in a dose-dependent manner, and the cells in the granule cell layer of olfactory bulb became disordered after DE exposure. The TUNEL staining showed that TUNEL positive cells in olfactory bulb tissue and neuronal apoptosis increased in the exposed groups compared with the control group (P＜0.05). The KEGG pathway analysis showed that DE associated with significant enrichment of TNF signaling pathway in olfactory bulb tissue. The qPCR results showed that the TNF-α relative expression level significantly increased by 67% and the IL-6 relative expression level by 340% in the DE high exposure dose group compared with the control group (P＜0.05). According to the immunofluorescence staining results, the numbers of activated microglia and astrocytes in olfactory bulb tissue significantly increased in the DE high exposure group, the relative fluorescence intensity of ionized calcium binding adaptor molecule 1 (IBA-1) increased by 120%, the granule cell layer relative fluorescence intensity of glial fibrillary acidic protein (GFAP) increased by 400%, and the glomerular layer relative fluorescence intensity of GFAP increased by 240% than those in the control group (P＜0.05). Conclusion Inhalation exposure to DE can lead to glial cell activation including microglia and astrocytes in olfactory bulb tissue by activating inflammatory pathways and releasing inflammatory factors TNF-α and IL-6, leading to neuronal apoptosis in olfactory bulb tissue.

Effects of mesencephalic astrocyte-derived neurotrophic factor on sepsis-associated acute kidney injury / 世界急诊医学杂志（英文）

@#BACKGROUND: To determine the protective role of mesencephalic astrocyte-derived neurotrophic factor (MANF) in regulating sepsis-associated acute kidney injury (S-AKI). METHODS: A total of 96 mice were randomly divided into the control group, control+MANF group, S-AKI group, and S-AKI+MANF group. The S-AKI model was established by injecting lipopolysaccharide (LPS) at 10 mg/kg intraperitoneally. MANF (200 μg/kg) was administered to the control+MANF and S-AKI+MANF groups. An equal dose of normal saline was administered daily intraperitoneally in the control and S-AKI groups. Serum and kidney tissue samples were obtained for biochemical analysis. Western blotting was used to detect the protein expression of MANF in the kidney, and enzyme-linked immunosorbent assay (ELISA) was used to determine expression of MANF in the serum, pro-inflammatory cytokines (tumor necrosis factor-α [TNF-α] and interleukin-6 [IL-6]). Serum creatinine (SCr), and blood urea nitrogen (BUN) were examined using an automatic biochemical analyzer. In addition, the kidney tissue was observed for pathological changes by hematoxylin-eosin staining. The comparison between two groups was performed by unpaired Student’s t-test, and statistics among multiple groups were carried out using Tukey’s post hoc test following one-way analysis of variance (ANOVA). A P-value <0.05 was considered statistically significant. RESULTS: At the early stage of S-AKI, MANF in the kidney tissue was up-regulated, but with the development of the disease, it was down-regulated. Renal function was worsened in the S-AKI group, and TNF-α and IL-6 were elevated. The administration of MANF significantly alleviated the elevated levels of SCr and BUN and inhibited the expression of TNF-α and IL-6 in the kidney. The pathological changes were more extensive in the S-AKI group than in the S-AKI+MANF group. CONCLUSION: MANF treatment may significantly alleviate renal injury, reduce the inflammatory response, and alleviate or reverse kidney tissue damage. MANF may have a protective effect on S-AKI, suggesting a potential treatment for S-AKI.

Changes to GFAP Immunoreactive Astrocytes in Medial Prefrontal Cortex Following Exposure to Chronic Stress and Antioxidant Supplementation in Rat Model

@#Introduction: Astrocytes are responsible for many essential functions of neurons in CNS. It has been recognised that chronic stress affects the morphology of astrocyte. Natural antioxidant such as honey has been used as one of the therapeutic strategies to lessen the damaging effect of chronic stress on our body. Therefore, the aim of the study is to explore the effect of natural antioxidant, Tualang honey (TH) on the morphology of astrocytes following chronic stress exposure. Methods: Thirty-two male rats were randomly divided into the 4 groups: (i) control, (ii) stress, (iii) honey, (iv) stress plus honey groups.TH was administered via oral gavage at dose of 1.0 g/kg body weight pre and post experiment. Chronic stress was exposed to animals in group (ii) and (iv) for consecutive 21 days. Anti GFAP immunohistochemistry method was employed to label astrocytes in the medial prefrontal cortex. The number of GFAP+ astrocytes and several parameters related to astrocyte processes were measured. Results: The present study showed that chronic stress reduced the GFAP immunoreactive astrocyte number and percentage of GFAP immunoreactive material. Chronic stress also caused a reduction in astrocyte process ramification as indicated by a reduction in astrocyte total number of processes, average length of processes and maximum number of intersections. However, antioxidant treatment using TH could not reverse these stress-induced changes to the astrocytes. Conclusion: These results demonstrate that chronic stress decreases the number of GFAP immunoreactive astrocyte and cause shrinking of astrocyte processes in stress-sensitive brain region, but these changes cannot be reversed by antioxidant treatment.

Mechanism of anterior cingulate cortex in modulating pain and anxiety-like behavior in chronic non-specific low back pain model rats / 中华行为医学与脑科学杂志

Objective:To explore the potential mechanisms of anterior cingulate cortex (ACC) in modulating pain behavior and anxiety-like behavior of rats with chronic non-specific low back pain induced by nerve growth factor (NGF).Methods:Ninety-six male SPF grade SD rats aged 8 weeks were randomly divided into four groups according the random number table method: control group, model group, control+ D-2-amino-5-phosphonopentanoate (D-AP5) group (control+ D-AP5 group) and model+ D-AP5 group, with 24 rats in each group.Low back pain model of rat was established by injection of NGF into multifidus muscle (left side) of the low backs of rats(two times with a five-day interval). Five days after modeling, rats in model+ D-AP5 group and control+ D-AP5 group were injected with the N-methyl-D-aspartate (NMDA) receptor antagonist D-AP5(2 μg, 0.3 μL) at the right side of the ACC once a day for consecutive 3 days, and rats in control group and model group were injected with the same amount of 0.9% sodium chloride solution. Seven days after modeling, the pain threshold of rats was evaluated by mechanical stimulation test and hot and cold plate test.The anxiety-like behavior was tested by open field test.The density of glial fibrillary acidic protein (GFAP) positive cells and c-Fos(a kind of immediate early gene) positive cells of the spinal cord were observed by immunofluorescence. The expression of GFAP, c-Fos, phosphorylated-c-Jun N-terminal kinases (p-JNK), monocyte chemoattractant protein-1 (MCP-1), and chemokine (C-X-C motif) ligand 1 (CXCL-1) proteins in the L2 segment of the spinal cord were detected by Western blot. SPSS 23.0 software was used for statistical analysis. One-way ANOVA was used to analyze normal distribution measurement data for comparison among multiple groups, and Tukey test was used for further pairwise comparisons. The Kruakal-Wallis H test was used for non-normal distribution measurement data, and Mann-Whitney U test was used for further pairwise comparisons with Bonferroni-corrected P-values. Results:In the experiments measuring pressure pain threshold (PPT) and paw withdrawal threshold (PWT), there were statistically significant differences in the PPT and PWT of rats among the four groups ( F=53.498, 41.939, both P<0.001). Seven days after modeling, PPT ((418.5±46.9) g) and PWT ( (55.6±7.1) g) in the ipsilateral side of the rats in model+ D-AP5 group were higher than those in model group ((290.0±32.0) g, (30.5±7.5) g) (both P<0.001). In the open field test, there were statistically significant differences in percentage of the inner zone distance ( H=11.922, P<0.01) and the percentage of inner zone time ( H=21.614, P<0.001) of rats among the four groups. The percentage of inner zone time in model+ D-AP5 group was higher than that in model group (5.6(4.3, 7.9) %, 3.1(2.1, 3.8) %) ( P<0.01). The results of immunofluorescence showed that there were statistically significant differences in the density of GFAP positive cells and c-Fos positive cells at the ipsilateral side of the superficial laminae of rats among the four groups ( H=49.085, F=18.120, both P<0.001). The density of GFAP positive cells (34.3(21.1, 47.5) cells/mm 2) and c-Fos positive cells ((52.7±39.4) cells/mm 2) at the ipsilateral side of the superficial laminae in model+ D-AP5 group were less than those in model group (76.5(68.6, 94.9) cells/mm 2, (112.4±63.7) cells/mm 2) (both P<0.001). The Western blot results showed that there were statistically significant differences in the protein expression of GFAP, c-Fos, p-JNK, MCP-1 and CXCL-1 in the L2 segment of rats among the four groups ( F=49.413, 38.437, 41.867, 36.735, 130.951, all P<0.001). The protein expression of GFAP (1.7±0.5), c-Fos (1.1±0.1), p-JNK (1.7±0.3), MCP-1 (1.0±0.4) and CXCL-1 (0.8±0.1) in the L2 segment in model+ D-AP5 group were lower than those in model group ((4.3±0.7), (2.6±0.5), (2.8±0.4), (2.9±0.4), (3.5±0.4)) (all P<0.01). Conclusion:ACC modulates mechanical hyperalgesia and anxiety-like behavior in chronic non-specific low back pain rats, which might be associated with the involvement of spinal astrocytes, p-JNK signal pathway and chemokines such as MCP-1 and CXCL-1.

Astrocytes in Chronic Pain: Cellular and Molecular Mechanisms / 神经科学通报·英文版

Chronic pain is challenging to treat due to the limited therapeutic options and adverse side-effects of therapies. Astrocytes are the most abundant glial cells in the central nervous system and play important roles in different pathological conditions, including chronic pain. Astrocytes regulate nociceptive synaptic transmission and network function via neuron-glia and glia-glia interactions to exaggerate pain signals under chronic pain conditions. It is also becoming clear that astrocytes play active roles in brain regions important for the emotional and memory-related aspects of chronic pain. Therefore, this review presents our current understanding of the roles of astrocytes in chronic pain, how they regulate nociceptive responses, and their cellular and molecular mechanisms of action.

Interactions Between Astrocytes and Oligodendroglia in Myelin Development and Related Brain Diseases / 神经科学通报·英文版

Astrocytes (ASTs) and oligodendroglial lineage cells (OLGs) are major macroglial cells in the central nervous system. ASTs communicate with each other through connexin (Cx) and Cx-based network structures, both of which allow for quick transport of nutrients and signals. Moreover, ASTs interact with OLGs through connexin (Cx)-mediated networks to modulate various physiological processes in the brain. In this article, following a brief description of the infrastructural basis of the glial networks and exocrine factors by which ASTs and OLGs may crosstalk, we focus on recapitulating how the interactions between these two types of glial cells modulate myelination, and how the AST-OLG interactions are involved in protecting the integrity of the blood-brain barrier (BBB) and regulating synaptogenesis and neural activity. Recent studies further suggest that AST-OLG interactions are associated with myelin-related diseases, such as multiple sclerosis. A better understanding of the regulatory mechanisms underlying AST-OLG interactions may inspire the development of novel therapeutic strategies for related brain diseases.

Association of Glial Activation and α-Synuclein Pathology in Parkinson's Disease / 神经科学通报·英文版

The accumulation of pathological α-synuclein (α-syn) in the central nervous system and the progressive loss of dopaminergic neurons in the substantia nigra pars compacta are the neuropathological features of Parkinson's disease (PD). Recently, the findings of prion-like transmission of α-syn pathology have expanded our understanding of the region-specific distribution of α-syn in PD patients. Accumulating evidence suggests that α-syn aggregates are released from neurons and endocytosed by glial cells, which contributes to the clearance of α-syn. However, the activation of glial cells by α-syn species produces pro-inflammatory factors that decrease the uptake of α-syn aggregates by glial cells and promote the transmission of α-syn between neurons, which promotes the spread of α-syn pathology. In this article, we provide an overview of current knowledge on the role of glia and α-syn pathology in PD pathogenesis, highlighting the relationships between glial responses and the spread of α-syn pathology.

Research progress on the role of astrocytes in radiation-induced brain injury / 中华放射肿瘤学杂志

Radiation-induced brain injury (RBI) is one of the complications after radiotherapy for head and neck malignant tumors, which seriously affects the quality of life of patients. The pathophysiological mechanism of RBI is not completely clear. Current studies suggest that it is involved in a variety of cells in the central nervous system (CNS), whereas astrocyte, as the largest number of glial cells in the CNS, plays an important role in maintaining the CNS homeostasis and responding to CNS injury. In this article, the role of astrocytes in RBI was reviewed.

Potential role of brain cell senescence in the pathogenesis of Alzheimer's disease / 药学学报

Cell senescence is characterized by permanent cell cycle arrest, accompanied by the changes in cell metabolism and epigenetic regulation. Alzheimer's disease (AD) is a common neurodegenerative disease, with the main symptoms of memory loss and cognitive impairment. A large number of studies have shown that the senescence of central nervous system cells such as astrocytes and microglia is closely related to the occurrence of AD. Inhibition of brain cell senescence is expected to provide new ideas and therapeutic strategies for the prevention and treatment of AD. This paper reviews the potential roles and mechanisms of senescence of brain cells in AD, and interaction effects among brain cells. This review will provide a new direction for the study of pathological mechanism of AD and the development of anti-AD drugs.

Entrainment of Astrocytic and Neuronal Ca2+ Population Dynamics During Information Processing of Working Memory in Mice / 神经科学通报·英文版

Astrocytes are increasingly recognized to play an active role in learning and memory, but whether neural inputs can trigger event-specific astrocytic Ca2+ dynamics in real time to participate in working memory remains unclear due to the difficulties in directly monitoring astrocytic Ca2+ dynamics in animals performing tasks. Here, using fiber photometry, we showed that population astrocytic Ca2+ dynamics in the hippocampus were gated by sensory inputs (centered at the turning point of the T-maze) and modified by the reward delivery during the encoding and retrieval phases. Notably, there was a strong inter-locked and antagonistic relationship between the astrocytic and neuronal Ca2+ dynamics with a 3-s phase difference. Furthermore, there was a robust synchronization of astrocytic Ca2+ at the population level among the hippocampus, medial prefrontal cortex, and striatum. The inter-locked, bidirectional communication between astrocytes and neurons at the population level may contribute to the modulation of information processing in working memory.

Developmental Origins of Human Cortical Oligodendrocytes and Astrocytes / 神经科学通报·英文版

Human cortical radial glial cells are primary neural stem cells that give rise to cortical glutaminergic projection pyramidal neurons, glial cells (oligodendrocytes and astrocytes) and olfactory bulb GABAergic interneurons. One of prominent features of the human cortex is enriched with glial cells, but there are major gaps in understanding how these glial cells are generated. Herein, by integrating analysis of published human cortical single-cell RNA-Seq datasets with our immunohistochemistical analyses, we show that around gestational week 18, EGFR-expressing human cortical truncated radial glial cells (tRGs) give rise to basal multipotent intermediate progenitors (bMIPCs) that express EGFR, ASCL1, OLIG2 and OLIG1. These bMIPCs undergo several rounds of mitosis and generate cortical oligodendrocytes, astrocytes and olfactory bulb interneurons. We also characterized molecular features of the cortical tRG. Integration of our findings suggests a general picture of the lineage progression of cortical radial glial cells, a fundamental process of the developing human cerebral cortex.

Baicalin treats cerebral ischemia reperfusion-induced brain edema in rats by inhibiting TRPV4 and AQP4 of astrocytes / 中国中药杂志

This study aims to explore the pharmacodynamic effect of baicalin on rat brain edema induced by cerebral ischemia reperfusion injury and discuss the mechanism from the perspective of inhibiting astrocyte swelling, which is expected to serve as a refe-rence for the treatment of cerebral ischemia with Chinese medicine. To be specific, middle cerebral artery occlusion(suture method) was used to induce cerebral ischemia in rats. Rats were randomized into normal group, model group, high-dose baicalin(20 mg·kg~(-1)) group, and low-dose baicalin(10 mg·kg~(-1)) group. The neurobehavior, brain index, brain water content, and cerebral infarction area of rats were measured 6 h and 24 h after cerebral ischemia. Brain slices were stained with hematoxylin and eosin(HE) for the observation of pathological morphology of cerebral cortex after baicalin treatment. Enzyme-linked immunosorbent assay(ELISA) was employed to determine the content of total L-glutathione(GSH) and glutamic acid(Glu) in brain tissue, Western blot to measure the content of glial fibrillary acidic protein(GFAP), aquaporin-4(AQP4), and transient receptor potential vanilloid type 4(TRPV4), and immunohistochemical staining to observe the expression of GFAP. The low-dose baicalin was used for exploring the mechanism. The experimental results showed that the neurobehavioral scores(6 h and 24 h of cerebral ischemia), brain water content, and cerebral infarction area of the model group were increased, and both high-dose and low-dose baicalin can lower the above three indexes. The content of GSH dropped but the content of Glu raised in brain tissue of rats in the model group. Low-dose baicalin can elevate the content of GSH and lower the content of Glu. According to the immunohistochemical staining result, the model group demonstrated the increase in GFAP expression, and swelling and proliferation of astrocytes, and the low-dose baicalin can significantly improve this situation. The results of Western blot showed that the expression of GFAP, TRPV4, and AQP4 in the cerebral cortex of the model group increased, and the low-dose baicalin reduce their expression. The cerebral cortex of rats in the model group was severely damaged, and the low-dose baicalin can significantly alleviate the damage. The above results indicate that baicalin can effectively relieve the brain edema caused by cerebral ischemia reperfusion injury in rats, possibly by suppressing astrocyte swelling and TRPV4 and AQP4.

Grain-sized moxibustion inhibits the progression of Alzheimer disease in 5XFAD transgenic mice / 针灸推拿医学（英文版）

Objective: To investigate whether grain-sized moxibustion at Xinshu (BL15) and Shenshu (BL23) can alleviate cognitive decline and other pathologic features in early-stage Alzheimer disease (AD) using transgenic mice with 5 familial AD mutations (5XFAD). Methods: The genotype of transgenic mice was detected by polymerase chain reaction. A total of 40 transgenic mice (1.5 months old) were randomly and equally allocated to an AD model group (5XFAD group) or a grain-sized moxibustion group (5XFAD + GM group), with 20 wild-type (WT) mice (C57BL/6J) serving as the normal control group (WT group). Mice in the 5XFAD + GM group were treated by grain-sized moxibustion at bilateral Xinshu (BL15) and Shenshu (BL23). Mice in the WT group and 5XFAD group received no treatment but were restrained to ensure exposure to a similar experimental condition. Cognitive function and memory were assessed with the Morris water maze and Y-maze tests. The amyloid β 40 (Aβ40) and amyloid β 42 (Aβ42) levels in the brain were evaluated by enzyme-linked immunosorbent assay; amyloid plaque deposition in brain tissue sections was detected by thioflavin-S staining; the expression of glial fibrillary acidic protein (GFAP), cluster of differentiation 11b (CD11b), brain-derived neurotrophic factor (BDNF), and choline acetyltransferase (ChAT) in the hippocampus and prefrontal cortex was analyzed by immunohistochemistry. Results: In the Morris water maze test, compared with the 5XFAD group, mice in the 5XFAD + GM group had a shorter escape latency and more target area crossings and spent more time in the target quadrant (P<0.05). In the Y-maze test, compared with the 5XFAD group, the number of training times of the 5XFAD + GM group was significantly decreased (P<0.05), together with more correct responses (P<0.05). Compared with the 5XFAD group, the levels of Aβ40 and Aβ42 in the brain tissue of the 5XFAD + GM group were significantly lower (P<0.05); in the hippocampus and prefrontal cortex, the total number of amyloid β plaque deposition were significantly lower (P<0.05); the expression levels of GFAP and CD11b were significantly reduced (P<0.05); and the expression levels of ChAT and BDNF were significantly increased (P<0.05).Conclusion: Grain-sized moxibustion at Xinshu (BL15) and Shenshu (BL23) greatly improves learning and memory functions, decreases the levels of Aβ40 and Aβ42, inhibits amyloid β plaque deposition, decreases the expression of GFAP and CD11b, and increases the expression of ChAT and BDNF in AD mice to inhibit the progression of AD.

Astrocytic Gap Junctions Contribute to Aberrant Neuronal Synchronization in a Mouse Model of MeCP2 Duplication Syndrome / 神经科学通报·英文版

Abnormal synchronous neuronal activity has been widely detected by brain imaging of autistic patients, but its underlying neural mechanism remains unclear. Compared with wild-type mice, our in vivo two-photon imaging showed that transgenic (Tg1) mice over-expressing human autism risk gene MeCP2 exhibited higher neuronal synchrony in the young but lower synchrony in the adult stage. Whole-cell recording of neuronal pairs in brain slices revealed that higher neuronal synchrony in young postnatal Tg1 mice was attributed mainly to more prevalent giant slow inward currents (SICs). Both in vivo and slice imaging further demonstrated more dynamic activity and higher synchrony in astrocytes from young Tg1 mice. Blocking astrocytic gap junctions markedly decreased the generation of SICs and overall cell synchrony in the Tg1 brain. Furthermore, the expression level of Cx43 protein and the coupling efficiency of astrocyte gap junctions remained unchanged in Tg1 mice. Thus, astrocytic gap junctions facilitate but do not act as a direct trigger for the abnormal neuronal synchrony in young Tg1 mice, revealing the potential role of the astrocyte network in the pathogenesis of MeCP2 duplication syndrome.

Rol de la neuroglia en el trastorno del espectro autista / Role of neuroglia in autism spectrum disorder

RESUMEN: El trastorno del espectro autista (TEA) se caracteriza por presentar déficits persistentes en la comunicación y en la interacción social. Además, patrones de comportamiento, intereses o actividades de tipo restrictivo o repetitivo. Su etiología es compleja y heterogenia, y los mecanismos neurobiológicos que dan lugar al fenotipo clínico aún no se conocen por completo. Las investigaciones apuntan a factores genéticos y ambientales que afectan el cerebro en desarrollo. Estos avances coinciden con un aumento en la comprensión de las funciones fisiológicas y el potencial patológico de la neuroglia en el sistema nervioso central (SNC) que llevó a la noción de la contribución fundamental de estas células en el TEA. Así, el objetivo de este artículo fue revisar brevemente los factores de riesgo clave asociados al TEA y luego, explorar la contribución de la neuroglia en este trastorno. Se destaca el rol de los astrocitos, los microglocitos y los oligodendrocitos en el control homeostático del SNC, en la regulación inmunitaria del cerebro y en la mielinización axonal, así como el mal funcionamiento y las alteraciones morfológicas de estas células en los cerebros autistas.

SUMMARY: Autism spectrum disorder (ASD) is characterized by persistent deficits in communication and social interaction, as well as restrictive or repetitive activities or interests. Its etiology is complex and heterogeneous, and the neurobiological mechanisms that give rise to the clinical phenotype are not yet fully understood. Research points to genetic and environmental factors that affect the developing brain. These advances are consistent with an enhanced understanding of the physiological functions and pathological potential of neuroglia in the central nervous system (CNS) which supports the conclusion of the contribution of these cells in ASD. Therefore, the objective of this article was to briefly review the key risk factors associated with ASD and then explore the contribution of glia in this disorder. The role of astrocytes, microgliocytes and oligodendrocytes in the homeostatic control of the CNS in the immune regulation of the brain and in axonal myelination, as well as malfunction and morphological alterations of these cells in autistic brains are emphasized.

Antagonism of Protease-Activated Receptor 4 Protects Against Traumatic Brain Injury by Suppressing Neuroinflammation via Inhibition of Tab2/NF-κB Signaling / 神经科学通报·英文版

Traumatic brain injury (TBI) triggers the activation of the endogenous coagulation mechanism, and a large amount of thrombin is released to curb uncontrollable bleeding through thrombin receptors, also known as protease-activated receptors (PARs). However, thrombin is one of the most critical factors in secondary brain injury. Thus, the PARs may be effective targets against hemorrhagic brain injury. Since the PAR1 antagonist has an increased bleeding risk in clinical practice, PAR4 blockade has been suggested as a more promising treatment. Here, we explored the expression pattern of PAR4 in the brain of mice after TBI, and explored the effect and possible mechanism of BMS-986120 (BMS), a novel selective and reversible PAR4 antagonist on secondary brain injury. Treatment with BMS protected against TBI in mice. mRNA-seq analysis, Western blot, and qRT-PCR verification in vitro showed that BMS significantly inhibited thrombin-induced inflammation in astrocytes, and suggested that the Tab2/ERK/NF-κB signaling pathway plays a key role in this process. Our findings provide reliable evidence that blocking PAR4 is a safe and effective intervention for TBI, and suggest that BMS has a potential clinical application in the management of TBI.

Decoding Cortical Glial Cell Development / 神经科学通报·英文版

Mouse cortical radial glial cells (RGCs) are primary neural stem cells that give rise to cortical oligodendrocytes, astrocytes, and olfactory bulb (OB) GABAergic interneurons in late embryogenesis. There are fundamental gaps in understanding how these diverse cell subtypes are generated. Here, by combining single-cell RNA-Seq with intersectional lineage analyses, we show that beginning at around E16.5, neocortical RGCs start to generate ASCL1

Rac1 Signaling in Amygdala Astrocytes Regulates Fear Memory Acquisition and Retrieval / 神经科学通报·英文版

The importance of astrocytes in behavior control is increasingly appreciated, but little is known about the effects of their dynamic activity in regulating learning and memory. In the present study, we constructed AAVs of photoactivatable and photoinactivatable Ras-related C3 botulinum toxin substrate 1 (Rac1) under the mGFAP promoter, which enabled the manipulation of Rac1 activity in astrocytes by optical stimulation in free-moving mice. We found that both up-regulation and down-regulation of astrocytic Rac1 activity in the basolateral amygdala (BLA) attenuated memory acquisition in a fear conditioning mouse model. Meanwhile, neuronal activation in the BLA induced by memory acquisition was inhibited under both the up- and down-regulation of astrocytic Rac1 activity during training. In terms of the impact on fear memory retrieval, we found both up- and down-regulation of BLA astrocytic Rac1 activity impaired memory retrieval of fear conditioning and memory retrieval-induced neuronal activation. Notably, the effect of astrocytic Rac1 on memory retrieval was reversible. Our results demonstrate that the normal activity of astrocytic Rac1 is necessary for the activation of neurons and memory formation. Both activation and inactivation of astrocytic Rac1 activity in the BLA reduced the excitability of neurons, and thereby impaired fear memory acquisition and retrieval.