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*

Alzheimer's disease (AD) is a multifactorial and heterogenic disorder. MiRNA is a class of non-coding RNAs with 19-22 nucleotides in length that can regulate the expression of target genes in the post-transcriptional level. It has been found that the miRNAome in AD patients is significantly altered in brain tissues, cerebrospinal fluid and blood circulation, as compared to healthy subjects. Experimental studies have suggested that expression changes in miRNA could drive AD onset and development via different mechanisms. Therefore, targeting miRNA expression to regulate the key genes involved in AD progression is anticipated to be a promising approach for AD prevention and treatment. Rodent AD models have demonstrated that targeting miRNAs could block biogenesis and toxicity of amyloid β, inhibit the production and hyper-phosphorylation of τ protein, prevent neuronal apoptosis and promote neurogenesis, maintain neural synaptic and calcium homeostasis, as well as mitigate neuroinflammation mediated by microglia. In addition, animal and human studies support the view that miRNAs are critical players contributing to the beneficial effects of cell therapy and lifestyle intervention to AD. This article reviews the most recent advances in the roles, mechanisms and applications of targeting miRNA in AD prevention and treatment based on rodent AD models and human intervention studies. The potential opportunities and challenges in clinical application of targeting miRNA for AD patients are also discussed.
Animals ; Humans ; MicroRNAs/genetics* ; Alzheimer Disease/prevention & control* ; Amyloid beta-Peptides ; Apoptosis ; Microglia

Mechanical allodynia (MA), including punctate and dynamic forms, is a common and debilitating symptom suffered by millions of chronic pain patients. Some peripheral injuries result in the development of bilateral MA, while most injuries usually led to unilateral MA. To date, the control of such laterality remains poorly understood. Here, to study the role of microglia in the control of MA laterality, we used genetic strategies to deplete microglia and tested both dynamic and punctate forms of MA in mice. Surprisingly, the depletion of central microglia did not prevent the induction of bilateral dynamic and punctate MA. Moreover, in dorsal root ganglion-dorsal root-sagittal spinal cord slice preparations we recorded the low-threshold Aβ-fiber stimulation-evoked inputs and outputs of superficial dorsal horn neurons. Consistent with behavioral results, microglial depletion did not prevent the opening of bilateral gates for Aβ pathways in the superficial dorsal horn. This study challenges the role of microglia in the control of MA laterality in mice. Future studies are needed to further understand whether the role of microglia in the control of MA laterality is etiology-or species-specific.
Mice ; Animals ; Hyperalgesia/metabolism* ; Microglia/metabolism* ; Disease Models, Animal ; Spinal Cord/metabolism* ; Spinal Cord Dorsal Horn/metabolism* ; Ganglia, Spinal/metabolism*

Abnormal brain-gut interaction is considered the core pathological mechanism behind the disorders of gut-brain interaction (DGBI), in which the intestinal microbiota plays an important role. Microglia are the "sentinels" of the central nervous system (CNS), which participate in tissue damage caused by traumatic brain injury, resist central infection and participate in neurogenesis, and are involved in the occurrence of various neurological diseases. With in-depth research on DGBI, we could find an interaction between the intestinal microbiota and microglia and that they are jointly involved in the occurrence of DGBI, especially in individuals with comorbidities of mental disorders, such as irritable bowel syndrome (IBS). This bidirectional regulation of microbiota and microglia provides a new direction for the treatment of DGBI. In this review, we focus on the role and underlying mechanism of the interaction between gut microbiota and microglia in DGBI, especially IBS, and the corresponding clinical application prospects and highlight its potential to treat DGBI in individuals with psychiatric comorbidities.
Humans ; Gastrointestinal Microbiome ; Irritable Bowel Syndrome/therapy* ; Microglia ; Brain Diseases ; Brain

Parkinson's disease (PD) is a common neurodegenerative disease in middle-aged and elderly people. In particular, increasing evidence has showed that astrocyte-mediated neuroinflammation is involved in the pathogenesis of PD. As a precious traditional Chinese medicine, bear bile powder (BBP) has a long history of use in clinical practice. It has numerous activities, such as clearing heat, calming the liver wind and anti-inflammation, and also exhibits good therapeutic effect on convulsive epilepsy. However, whether BBP can prevent the development of PD has not been elucidated. Hence, this study was designed to explore the effect and mechanism of BBP on suppressing astrocyte-mediated neuroinflammation in a mouse model of PD. PD-like behavior was induced in the mice by intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) (30 mg·kg^-1) for five days, followed by BBP (50, 100, and 200 mg·kg^-1) treatment daily for ten days. LPS stimulated rat C6 astrocytic cells were used as a cell model of neuroinflammation. THe results indicated that BBP treatment significantly ameliorated dyskinesia, increased the levels of tyrosine hydroxylase (TH) and inhibited astrocyte hyperactivation in the substantia nigra (SN) of PD mice. Furthermore, BBP decreased the protein levels of glial fibrillary acidic protein (GFAP), cyclooxygenase 2 (COX2) and inducible nitric oxide synthase (iNOS), and up-regulated the protein levels of takeda G protein-coupled receptor 5 (TGR5) in the SN. Moreover, BBP significantly activated TGR5 in a dose-dependent manner, and decreased the protein levels of GFAP, iNOS and COX2, as well as the mRNA levels of GFAP, iNOS, COX2, interleukin (IL) -1β, IL-6 and tumor necrosis factor-α (TNF-α) in LPS-stimulated C6 cells. Notably, BBP suppressed the phosphorylation of protein kinase B (AKT), inhibitor of NF-κB (IκBα) and nuclear factor-κB (NF-κB) proteins in vivo and in vitro. We also observed that TGR5 inhibitor triamterene attenuated the anti-neuroinflammatory effect of BBP on LPS-stimulated C6 cells. Taken together, BBP alleviates the progression of PD mice by suppressing astrocyte-mediated inflammation via TGR5.
Humans ; Mice ; Rats ; Animals ; Aged ; Middle Aged ; Parkinson Disease/pathology* ; Astrocytes/pathology* ; Powders/therapeutic use* ; Ursidae/metabolism* ; NF-kappa B/metabolism* ; Neuroinflammatory Diseases ; Neurodegenerative Diseases/metabolism* ; Cyclooxygenase 2/metabolism* ; Lipopolysaccharides/pharmacology* ; Bile ; Mice, Inbred C57BL ; Microglia ; Disease Models, Animal

OBJECTIVE: To investigate the effect of acetylcorynoline (Ace) for promoting functional recovery of injured spinal cord in rats and explore the underlying mechanism. METHODS: Rat models of spinal cord injury (SCI) were treated with intraperitoneal injection of different concentrations of Ace, with the sham-operated rats as the control group. After the treatment, the changes in motor function of the rats and the area of spinal cord injury were assessed with BBB score and HE staining, and the changes in pro-inflammatory cytokine levels and microglial activation were determined using PCR, ELISA and immunofluorescence staining. In a lipopolysaccharide (LPS)-treated BV2 cell model, the effects of different concentrations of Ace or DMSO on microglial activation and inflammatory cytokine production were observed. Network pharmacology analysis was performed to predict the target protein and signaling mechanism that mediated the inhibitory effect of Ace on microglia activation, and AutoDock software was used for molecular docking between Ace and the target protein. A signaling pathway blocker (Osimertinib) was used to verify the signaling mechanism in rat models of SCI and LPS-treated BV2 cell model. RESULTS: In rat models of SCI, Ace treatment significantly increased the BBB score, reduced the area of spinal cord injury, and lowered the number of activated microglia cells and the levels of pro-inflammatory cytokines (P < 0.05). The cell experiments showed that Ace treatment significantly lower the level of cell activation and the production of inflammatory cytokines in LPS-treated BV2 cells (P < 0.05). Network pharmacology analysis suggested that EGFR was the main target of Ace, and they bound to each other via hydrogen bonds as shown by molecular docking. Western blotting confirmed that Ace inhibited the activation of the EGFR/MAPK signaling pathway in injured mouse spinal cord tissue and in LPS-treated BV2 cells, and its inhibitory effect was comparable to that of Osimertinib. CONCLUSION In rat models of SCI, treatment with Ace can inhibit microglia-mediated inflammatory response by regulating the EGFR/MAPK pathway, thus promoting tissue repair and motor function recovery.
Mice ; Animals ; Rats ; Recovery of Function ; Lipopolysaccharides ; Microglia ; Molecular Docking Simulation ; Spinal Cord Injuries ; Signal Transduction ; Cytokines ; ErbB Receptors

Triggering receptor expressed on myeloid cells 2 (TREM2) is a membrane receptor on myeloid cells and plays an important role in the body's immune defense. Recently, TREM2 has received extensive attention from researchers, and its activity has been found in Alzheimer's disease, neuroinflammation, and traumatic brain injury. The appearance of TREM2 is usually accompanied by changes in apolipoprotein E (ApoE), and there has been a lot of research into their structure, as well as the interaction mode and signal pathways involved in them. As two molecules with broad and important roles in the human body, understanding their correlation may provide therapeutic targets for certain diseases. In this article, we reviewed several diseases in which TREM2 and ApoE are synergistically involved in the development. We further discussed the positive or negative effects of the TREM2-ApoE pathway on nervous system immunity and inflammation.
Humans ; Alzheimer Disease/metabolism* ; Apolipoproteins E/genetics* ; Microglia/metabolism* ; Myeloid Cells/metabolism* ; Signal Transduction ; Neuroinflammatory Diseases

This study was aimed to investigate the effect of hypoxia on lipopolysaccharide (LPS)-induced CXC-chemokine ligand-10 (CXCL10) expression and the underlying mechanism. C57BL/6J mice were randomly divided into control, hypoxia, LPS, and hypoxia combined with LPS groups. The LPS group was intraperitoneally injected with 0.5 mg/kg LPS, and the hypoxia group was placed in a hypobaric hypoxia chamber (simulated altitude of 6 000 m). The serum and hippocampal tissue samples were collected after 6 h of the treatment. The levels of CXCL10 in the serum and hippocampal tissue of mice were detected by ELISA. The microglia cell line BV2 and primary microglia were stimulated with hypoxia (1% O₂) and/or LPS (100 ng/mL) for 6 h. The mRNA expression level of CXCL10 and its content in culture supernatant were detected by real-time quantitative PCR and ELISA, respectively. The phosphorylation levels of nuclear factor κB (NF-κB) signaling pathway-related proteins, p65 and IκBα, were detected by Western blot. Moreover, after NF-κB signaling pathway being blocked with a small molecular compound, PDTC, CXCL10 mRNA expression level was detected in the BV2 cells. The results showed that in the LPS-induced mouse inflammatory model, hypoxia treatment could promote LPS-induced up-regulation of CXCL10 in both serum and hippocampus. Compared with the cells treated with LPS alone, the expression of CXCL10 mRNA and the content of CXCL10 in the culture supernatant of BV2 cells treated with hypoxia combined with LPS were significantly increased. The CXCL10 mRNA level of primary microglial cells treated with hypoxia combined with LPS was significantly up-regulated. Compared with the cells treated with hypoxia or LPS alone, the phosphorylation levels of p65 and IκBα in the BV2 cells treated with hypoxia combined with LPS were significantly increased. PDTC blocked the induction of CXCL10 gene expression by LPS in the BV2 cells. These results suggest that hypoxia promotes LPS-induced expression of CXCL10 in both animal and cell models, and NF-κB signaling pathway plays an important role in this process.
Animals ; Mice ; Chemokines, CXC/pharmacology* ; Hypoxia ; Ligands ; Lipopolysaccharides/pharmacology* ; Mice, Inbred C57BL ; Microglia/metabolism* ; NF-kappa B/metabolism* ; NF-KappaB Inhibitor alpha/pharmacology* ; RNA, Messenger/metabolism*

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*