Interactions between brain-resident and peripheral infiltrated immune cells are thought to contribute to neuroplasticity after cerebral ischemia. However, conventional bulk sequencing makes it challenging to depict this complex immune network. Using single-cell RNA sequencing, we mapped compositional and transcriptional features of peri-infarct immune cells. Microglia were the predominant cell type in the peri-infarct region, displaying a more diverse activation pattern than the typical pro- and anti-inflammatory state, with axon tract-associated microglia (ATMs) being associated with neuronal regeneration. Trajectory inference suggested that infiltrated monocyte-derived macrophages (MDMs) exhibited a gradual fate trajectory transition to activated MDMs. Inter-cellular crosstalk between MDMs and microglia orchestrated anti-inflammatory and repair-promoting microglia phenotypes and promoted post-stroke neurogenesis, with SOX2 and related Akt/CREB signaling as the underlying mechanisms. This description of the brain's immune landscape and its relationship with neurogenesis provides new insight into promoting neural repair by regulating neuroinflammatory responses.
Humans ; Ischemic Stroke ; Brain/metabolism* ; Macrophages ; Brain Ischemia/metabolism* ; Microglia/metabolism* ; Gene Expression Profiling ; Anti-Inflammatory Agents ; Neuronal Plasticity/physiology* ; Infarction/metabolism*

This study aims to investigate the effect of Bombyx Batryticatus extract(BBE) on behaviors of rats with global cerebral ischemia reperfusion(I/R) and the underlying mechanism. The automatic coagulometer was used to detect the four indices of human plasma coagulation after BBE intervention for quality control of the extract. Sixty 4-week-old male SD rats were randomized into sham operation group(equivalent volume of normal saline, ip), model group(equivalent volume of normal saline, ip), positive drug group(900 IU·kg~(-1) heparin, ip), and low-, medium-, and high-dose BBE groups(0.45, 0.9, and 1.8 mg·g~(-1)·d~(-1) BBE, ip). Except the sham operation group, rats were subjected to bilateral common carotid artery occlusion followed by reperfusion(BCCAO/R) to induce I/R. The administration lasted 7 days for all the groups. The behaviors of rats were examined by beam balance test(BBT). Morphological changes of brain tissue were observed based on hematoxylin-eosin(HE) staining. Immunofluorescence method was used to detect common leukocyte antigen(CD45), leukocyte differentiation antigen(CD11b), and arginase-1(Arg-1) in cerebral cortex(CC). The protein expression of interleukin-1β(IL-1β), interleukin-4(IL-4), interleukin-6(IL-6), and interleukin-10(IL-10) was detected by enzyme-linked immunosorbent assay(ELISA). The non-targeted metabonomics was employed to detect the levels of metabolites in plasma and CC of rats after BBE intervention. The results of quality control showed that the BBE prolonged the activated partial thromboplastin time(APTT), prothrombin time(PT), and thrombin time(TT) of human plasma, which was similar to the anticoagulation effect of BBE obtained previously. The results of behavioral test showed that the BBT score of the model group increased compared with that of the sham operation group. Compared with the model group, BBE reduced the BBT score. As for the histomorphological examination, compared with the sham operation group, the model group showed morphological changes of a lot of nerve cells in CC. The nerve cells with abnormal morphology in CC decreased after the intervention of BBE compared with those in the model group. Compared with the sham operation group, the model group had high average fluorescence intensity of CD45 and CD11b in the CC. The average fluorescence intensity of CD11b decreased and the average fluorescence intensity of Arg-1 increased in CC in the low-dose BBE group compared with those in the model group. The average fluorescence intensity of CD45 and CD11b decreased and the average fluorescence intensity of Arg-1 increased in medium-and high-dose BBE groups compared with those in the model group. The expression of IL-1β and IL-6 was higher and the expression of IL-4 and IL-10 was lower in the model group than in the sham operation group. The expression of IL-1β and IL-6 was lower and the expression of IL-4 and IL-10 was higher in the low-dose, medium-dose, and high-dose BBE groups than in the model group. The results of non-targeted metabonomics showed that 809 metabolites of BBE were identified, and 57 new metabolites in rat plasma and 45 new metabolites in rat CC were found. BBE with anticoagulant effect can improve the behaviors of I/R rats, and the mechanism is that it promotes the polarization of microglia to M2 type, enhances its anti-inflammatory and phagocytic functions, and thus alleviates the damage of nerve cells in CC.
Humans ; Rats ; Male ; Animals ; Interleukin-10 ; Rats, Sprague-Dawley ; Interleukin-4/metabolism* ; Bombyx ; Interleukin-6/metabolism* ; Microglia/metabolism* ; Saline Solution/metabolism* ; Reperfusion Injury/metabolism* ; Brain Ischemia/metabolism* ; Cerebral Infarction ; Reperfusion ; Neurons

Dependovirus/genetics* ; Microglia ; Cells, Cultured ; Transduction, Genetic

OBJECTIVE: To observe the effects of electro-scalp acupuncture （ESA） on the expression of microglial markers CD206 and CD32, as well as interleukin (IL)-6, IL-1β, and IL-10 in the ischemic cortex of rats with ischemic stroke, and to explore the mechanisms of ESA on alleviating inflammatory damage of ischemic stroke. METHODS: Sixty 7-week-old male SD rats were randomly selected, with 15 rats assigned to a sham surgery group. The remaining rats were treated with suture method to establish rat model of middle cerebral artery occlusion (MCAO). The rats with successful model were randomly divided into a model group, a VitD₃ group, and an ESA group, with 15 rats in each group. In the ESA group, ESA was performed bilaterally at the "top-temporal anterior oblique line" with disperse-dense wave, a frequency of 2 Hz/100 Hz, and an intensity of 1 mA. Each session lasted for 30 min, once daily, for a total of 7 days. The VitD₃ group were treated with intragastric administration of 1,25-dihydroxyvitamin D₃ (1,25-VitD₃) solution (3 ng/100 g), once daily for 7 days. The neurological deficit scores and neurobehavioral scores were assessed before and after the intervention. After the intervention, the brain infarct volume was evaluated using 2,3,5-triphenyltetrazolium chloride (TTC) staining. Immunofluorescence double staining was performed to detect the protein expression of CD32 and CD206 in the ischemic cortex. Western blot analysis was conducted to measure the protein expression of IL-6, IL-1β, and IL-10 in the ischemic cortex. RESULTS: Compared with the sham surgery group, the model group showed increased neurological deficit scores and neurobehavioral scores (P<0.01), increased brain infarct volume (P<0.01), increased protein expression of CD32, IL-6, and IL-1β in the ischemic cortex (P<0.01), and decreased protein expression of CD206 and IL-10 in the ischemic cortex (P<0.01). Compared with the model group, both the ESA group and the VitD₃ group showed decreased neurological deficit scores and neurobehavioral scores (P<0.01), reduced brain infarct volume (P<0.01), decreased protein expression of CD32, IL-6, and IL-1β in the ischemic cortex (P<0.01), and increased protein expression of CD206 and IL-10 in the ischemic cortex (P<0.01). Compared with the VitD₃ group, the ESA group had lower neurological deficit score (P<0.05), larger brain infarct volume (P< 0.05), and lower protein expression of CD32, CD206, IL-1β, and IL-10 in the ischemic cortex (P<0.01, P<0.05). CONCLUSION ESA could improve neurological function in MCAO rats, and its mechanism may be related to promoting microglial M1-to-M2 polarization and alleviating inflammatory damage.
Male ; Animals ; Rats ; Rats, Sprague-Dawley ; Ischemic Stroke ; Interleukin-10 ; Interleukin-6/genetics* ; Microglia ; Scalp ; Acupuncture Therapy ; Vitamins ; Infarction, Middle Cerebral Artery

Sleep is an extremely important physiological state to maintain human life. Sleep disorders can not only cause anxiety and depression, but also induce multi-system diseases that seriously affect brain function and physical health. The neuroinflammation is a key pathological process after sleep disorders, which can induce a series of nervous system diseases. In recent years, the role of microglia activation in neuroinflammation has been paid more and more attention and become a research hotspot in this field. The imbalance of the central microenvironment after sleep disorders leads to changes in the activation and polarization of microglia, which triggers neuroinflammatory response. The activation and polarization of microglia in the sleep disorders are regulated by multiple signaling pathways and complex molecular mechanisms. This paper summarizes five signaling pathways of microglia activation in central inflammation induced by sleep disorders, including P2X7 receptor (P2X7R), p38MAPK, Toll-like receptor 4 (TLR4)/NF-κB, JAK/STAT, and α7 nicotinic acetylcholine receptor (α7-nAChR) pathways, in order to provide reference for further research and clinical treatment targets selection of sleep disorders.
Humans ; Neuroinflammatory Diseases ; Microglia/metabolism* ; Signal Transduction/physiology* ; NF-kappa B/metabolism* ; Inflammation/metabolism* ; Sleep Wake Disorders/metabolism*

The aim of this study was to investigate the growth characteristics of primarily cultured astrocytes and microglia of different generations and then optimize the method for obtaining primary astrocytes and microglia effectively. Primarily cultured microglia were isolated and purified from the cortices of neonatal mice. The proliferation curve of mixed glia cells was measured by Cell Counting Kit-8 (CCK-8) assay, the proportion of astrocytes and microglia was detected by flow cytometry, and the polarization of the two types of glia cells was identified by immunofluorescence staining. Cell growth results showed that the mixed glia cells of P0 and P1 generation had the best proliferative activity; 97.3% of the high purity microglia could be obtained by mechanical shaking at 170 r/min for 30 min, and there was no significant difference in the morphology of ionized calcium-binding adapter molecule 1 (Iba-1) positive microglia and the proportion of M1 and M2 phenotype among the P0, P1 and P2 generations of microglia isolated by the above methods. Moreover, 95.7 % of the high purity astrocytes could be obtained by astrocyte cell surface antigen-2 (ACSA-2) magnetic beads separation, and there was no significant difference in the morphology of glial fibrillary acidic protein (GFAP) positive astrocyte and the proportion of A1 and A2 phenotype among the P0, P1 and P2 generations of astrocyte isolated by the above methods. Taken together, this study observed the growth characteristics of primarily cultured microglia and astrocyte in vitro, and then proved the best generations for purifying microglia and astrocytes. Finally, we optimized the methods of obtaining microglia and astrocyte, and verified that continuous culture within 2 generations will not affect the functional phenotypes of glia cells. These results provide technical support for studying the molecular mechanism of inflammation-associated diseases in nervous system.
Mice ; Animals ; Astrocytes/metabolism* ; Microglia/metabolism* ; Cell Count ; Flow Cytometry/methods* ; Cell Proliferation ; Cells, Cultured

The effect and mechanism of Heixiaoyao Powder on the polarization of microglia(MG) in APP/PS1 double transgenic mice were explored based on NADPH oxidase 2(NOX2)/reactive oxygen species(ROS)/nuclear factor kappaB(NF-κB) signaling pathway. Fifty 4-month-old male APP/PS1 mice were randomly divided into a model group, an MCC950 group(10 mg·kg~(-1)), and low-, medium-, and high-dose Heixiaoyao Powder groups(6.45, 12.89, and 25.78 g·kg~(-1)). Thirty male C57BL/6J mice of the same age and strain were randomly divided into a blank group, a blank + intragastric intervention group, and a blank + intraperitoneal injection group. Drug intervention lasted 90 days. Morris water maze test was used to detect learning and cognitive ability. Nissl staining and transmission electron microscopy were used to observe the pathological morphology and ultrastructure of hippocampal neurons. Immunofluorescence was used to detect the positive expression of M1-type marker CD16/32~+/Iba-1~+, M2-type marker CD206~+/Iba-1~+ of MG and the expression of hippocampal ROS. The colorimetric method was used to detect the content of malondialdehyde(MDA) and superoxide dismutase(SOD) in the hippocampus. Enzyme linked immunosorbent assay(ELISA) was used to detect the levels of inflammatory factors, including interleukin-6(IL-6), interleukin-8(IL-8), and tumor necrosis factor-α(TNF-α), in the hippocampus. Western blot was used to detect the protein expression of β-amyloid protein(Aβ), Iba-1, CD16/32, CD206, NOX2, NF-κB, p-NF-κB, NF-κB inhibitor alpha(IκBα), and p-IKBα in the hippocampus. The results showed that as compared with the blank group, the model group showed prolonged target quadrant movement distance and escape latency(P<0.01), shortened target quadrant retention time and percentage(P<0.01), disorganized neuronal cells with swelling, nuclear disappearance or bias, reduced number of cells, dissolved or absent Nissl bodies, and a clear area in the cytoplasm, damaged and shrunk cell membrane with abnormal cell morphology, few organelles in the cytoplasm, reduced and swollen mitochondria, increased MG M1-type marker CD16/32~+/Iba-1~+(P<0.01), decreased M2-type marker CD206~+/Iba-1~+(P<0.01), increased ROS activity and MDA content(P<0.01), decreased SOD level(P<0.01), elevated inflammatory factors IL-6, IL-8, and TNF-α(P<0.01), up-regulated protein expression and phosphorylation of Aβ, CD16/32, Iba-1, NOX2, NF-κB, and IKBα(P<0.01), and down-regulated CD206(P<0.01). There was no statistically significant difference between the blank group, the blank + intragastric intervention group, and the blank + intraperitoneal injection group. After the intervention of Heixiaoyao Powder, the Heixiaoyao Powder groups showed shortened target quadrant movement distance and escape latency(P<0.01), prolonged target quadrant retention time and percentage(P<0.01), increased and neatly arranged cells with relieved swelling, increased Nissl bodies, regular cell morphology, and intact cell membrane, relieved swelling of mitochondria, slightly expanded endoplasmic reticulum, decreased CD16/32~+/Iba-1~+(P<0.05 or P<0.01), increased CD206~+/Iba-1~+(P<0.01), decreased ROS activity and MDA content(P<0.01), increased SOD level(P<0.01), decreased content of inflammatory factors IL-6, IL-8, and TNF-α(P<0.01), down-regulated protein expression and phosphorylation of Aβ, CD16/32, Iba-1, NOX2, NF-κB, and IKBα(P<0.01), and up-regulated CD206(P<0.01). In conclusion, Heixiaoyao Powder can alleviate neuronal damage and improve the learning and memory abilities of APP/PS1 mice. The mechanism of action may be related to the inhibition of NOX2/ROS/NF-κB signaling pathway, regulating the polarization of MG, increasing the expression of M2 type, inhibiting the expression of M1 type, and reducing the release of inflammatory factor.
Mice ; Male ; Animals ; NF-kappa B/genetics* ; Microglia ; Reactive Oxygen Species ; Interleukin-8 ; Powders ; Tumor Necrosis Factor-alpha ; Interleukin-6 ; Mice, Inbred C57BL ; Signal Transduction ; Mice, Transgenic ; Superoxide Dismutase

This study aims to explore the neuroprotective effect of bilobalide(BB) and the mechanisms such as inhibiting inflammatory response in macrophage/microglia, promoting neurotrophic factor secretion, and interfering with the activation and differentiation of peripheral CD4~+ T cells. BB of different concentration(12.5, 25, 50, 100 μg·mL~(-1)) was used to treat the RAW264.7 and BV2 cells for 24 h. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay and cell counting kit-8(CCK-8) were employed to detect the cytotoxicity of BB and appropriate concentration was selected for further experiment. Lipopolysaccharide(LPS) was applied to elicit inflammation in RAW264.7 and BV2 cells, mouse bone marrow-derived macrophages(BMDMs), and primary microglia, respectively. The effect of BB on cell proliferation and secretion of inflammatory cytokines and neurotrophic factors was detected by enzyme-linked immunosorbent assay(ELISA). Spleen monocytes of C57BL/6 female mice(7-8 weeks old) were isolated, and CD4~+ T cells were separated by magnetic beads under sterile conditions. Th17 cells were induced by CD3/CD28 and the conditioned medium for eliciting the inflammation in BMDMs. The content of IL-17 cytokines in the supernatant was detected by ELISA to determine the effect on the activation and differentiation of CD4~+ T cells. In addition, PC12 cells were incubated with the conditioned medium for eliciting inflammation in BMDMs and primary microglia and the count and morphology of cells were observed. The cytoto-xicity was determined by lactate dehydrogenase(LDH) assay. The result showed that BB with the concentration of 12.5-100 μg·mL~(-1) had no toxicity to RAW264.7 and BV2 cells, and had no significant effect on the activity of cell model with low inflammation. The 50 μg·mL~(-1) BB was selected for further experiment, and the results indicated that BB inhibited LPS-induced secretion of inflammatory cytokines. The experiment on CD4~+ T cells showed that the conditioned medium for LPS-induced inflammation in BMDMs promoted the activation and differentiation of CD4~+ T cells, while the conditioned medium of the experimental group with BB intervention reduced the activation and differentiation of CD4~+ T cells. In addition, BB also enhanced the release of neurotrophic factors from BMDMs and primary microglia. The conditioned medium after BB intervention can significantly reduce the death of PC12 neurons, inhibit neuronal damage, and protect neurons. To sum up, BB plays a neuroprotective role by inhibiting macrophage and microglia-mediated inflammatory response and promoting neurotrophic factors.
Female ; Rats ; Mice ; Animals ; Bilobalides/pharmacology* ; Neuroprotection ; Lipopolysaccharides/toxicity* ; Culture Media, Conditioned/pharmacology* ; Mice, Inbred C57BL ; Macrophages/metabolism* ; Microglia ; Cytokines/metabolism* ; Nerve Growth Factors/pharmacology* ; Inflammation/metabolism*

Depression exists with high prevalence and heavy disease burden. Stress events play a key role in the occurrence of depression, but the pathological mechanism has not been fully clarified by reason of the complexity and heterogeneity. In recent years, neuroinflammation as a pathological mechanism of depression has received extensive attention. The activated microglia is regarded as the marker of neuroinflammation, which is an important link of stress-induced depression. Stress might induce microglia activation through pattern recognition receptors(PRR), intestinal flora, hypothalamic-pituitary-adrenal(HPA) axis, and other pathways. Cross-talk between impaired microglia function and neurobiological factors such as inflammatory cytokines, serotonin metabolism, and neuroplasticity may lead to depression. At present, a large number of studies have proved that traditional Chinese medicine(TCM) plays an anti-depressive role by inhibiting microglia activation, which may be potential treatment strategies for depressive disorder. This paper reviewed the research progress of stress-induced microglia activation in depression and summarized the mechanism of TCM against depression with regard to microglia, hoping to provide experimental evidence and consideration for TCM against depression through microglia.
Humans ; Cytokines/metabolism* ; Depression/drug therapy* ; Medicine, Chinese Traditional ; Microglia/metabolism* ; Neuroinflammatory Diseases

This study aims to investigate the effects of baicalein(BAI) on lipopolysaccharide(LPS)-induced human microglial clone 3(HMC3) cells, with a focus on suppressing inflammatory responses and elucidating the potential mechanism underlying the therapeutic effects of BAI on ischemic stroke via modulating the cAMP-PKA-NF-κB/CREB pathway. The findings have significant implications for the application of traditional Chinese medicine in treating cerebral ischemic diseases. First, the safe dosage of BAI was screened, and then an inflammation model was established with HMC3 cells by induction with LPS for 24 h. The cells were assigned into a control group, a model group, and high-, medium-, and low-dose(5, 2.5, and 1.25 μmol·L~(-1), respectively) BAI groups. The levels of superoxide dismutase(SOD) and malondialdehyde(MDA) in cell extracts, as well as the levels of interleukin-1β(IL-1β), IL-6, tumor necrosis factor-α(TNF-α), and cyclic adenosine monophosphate(cAMP) in the cell supernatant, were measured. Western blot was performed to determine the expression of protein kinase A(PKA), phosphorylated cAMP-response element binding protein(p-CREB), and nuclear factor-kappa B p65(NF-κB p65). Hoechst 33342/PI staining was employed to assess cell apoptosis. High and low doses of BAI were used for treatment in the research on the mechanism. The results revealed that BAI at the concentrations of 10 μmol·L~(-1) and below had no impact on normally cultured HMC3 cells. LPS induction at 200 ng·mL~(-1) for 24 h reduced the SOD activity and increased the MDA content in HMC3 cells. However, 5, 2.5, and 1.25 μmol·L~(-1) BAI significantly increased the SOD activity and 5 μmol·L~(-1) BAI significantly decreased the MDA content. In addition, BAI ameliorated the M1 polarization of HMC3 cells induced by LPS, as indicated by cellular morphology. The results of ELISA demonstrated that BAI significantly lowered the levels of TNF-α, IL-1β, IL-6, and cAMP in the cell supernatant. Western blot revealed that BAI up-regulated the protein levels of PKA and p-CREB while down-regulating the expression of NF-κB p65. Hoechst 33342/PI staining results indicated that BAI mitigated the apoptosis of HMC3 cells. Overall, the results indicated that BAI had protective effects on the HMC3 cells induced by LPS, and could inhi-bit inflammatory response and improve cell apoptosis, which might be related to the regulation of the cAMP-PKA-NF-κB/CREB pathway.
Humans ; NF-kappa B/metabolism* ; Microglia ; Tumor Necrosis Factor-alpha/metabolism* ; Interleukin-6/metabolism* ; Lipopolysaccharides/pharmacology* ; Cyclic AMP-Dependent Protein Kinases/metabolism* ; Superoxide Dismutase/metabolism*