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

OBJECTIVE: To investigate the molecular mechanisms underlying the beneficial effect of electroacupuncture (EA) in experimental models of Alzheimer's disease (AD) in vivo. METHODS: Senescence-accelerated mouse prone 8 (SAMP8) mice were used as AD models and received EA at Yingxiang (LI 20, bilateral) and Yintang (GV 29) points for 20 days. For certain experiments, SAMP8 mice were injected intravenously with human fibrin (2 mg). The Morris water maze test was used to assess cognitive and memory abilities. The changes of tight junctions of blood-brain barrier (BBB) in mice were observed by transmission electron microscope. The expressions of fibrin, amyloid- β (Aβ), and ionized calcium-binding adapter molecule 1 (IBa-1) in mouse hippocampus (CA1/CA3) were detected by reverse transcription-quantitative polymerase chain reaction (qRT-PCR), Western blot or immunohistochemical staining. The expression of fibrin in mouse plasma was detected by enzyme-linked immunosorbent assay. The expressions of tight junction proteins zonula occludens-1 and claudin-5 in hippocampus were detected by qRT-PCR and immunofluorescence staining. Apoptosis of hippocampal neurons was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining. RESULTS: Fibrin was time-dependently deposited in the hippocampus of SAMP8 mice and this was inhibited by EA treatment (P<0.05 or P<0.01). Furthermore, EA treatment suppressed the accumulation of Aβ in the hippocampus of SAMP8 mice (P<0.01), which was reversed by fibrin injection (P<0.05 or P<0.01). EA improved SAMP8 mice cognitive impairment and BBB permeability (P<0.05 or P<0.01). Moreover, EA decreased reactive oxygen species levels and neuroinflammation in the hippocampus of SAMP8 mice, which was reversed by fibrin injection (P<0.05 or P<0.01). Mechanistically, EA inhibited the promoting effect of fibrin on the high mobility group box protein 1 (HMGB1)/toll-like receptor 4 (TLR4) and receptor for advanced glycation end products (RAGE)/nicotinamide adenine dinucleotide phosphate (NADPH) signaling pathways (P<0.01). CONCLUSION EA may potentially improve cognitive impairment in AD via inhibition of fibrin/A β deposition and deactivation of the HMGB1/TLR4 and RAGE/NADPH signaling pathways.
Mice ; Humans ; Animals ; NADP/metabolism* ; Toll-Like Receptor 4 ; HMGB1 Protein/metabolism* ; Receptor for Advanced Glycation End Products/metabolism* ; Blood-Brain Barrier/metabolism* ; Neuroinflammatory Diseases ; Electroacupuncture ; Alzheimer Disease/therapy* ; Hippocampus/metabolism* ; Amyloid beta-Peptides/metabolism*

Over the past few decades, complementary and alternative treatments have become increasingly popular worldwide. The purported therapeutic characteristics of natural products have come under increased scrutiny both in vitro and in vivo as part of efforts to legitimize their usage. One such product is tea tree oil (TTO), a volatile essential oil primarily obtained from the native Australian plant, Melaleuca alternifolia, which has diverse traditional and industrial applications such as topical preparations for the treatment of skin infections. Its anti-inflammatory-linked immunomodulatory actions have also been reported. This systematic review focuses on the anti-inflammatory effects of TTO and its main components that have shown strong immunomodulatory potential. An extensive literature search was performed electronically for data curation on worldwide accepted scientific databases, such as Web of Science, Google Scholar, PubMed, ScienceDirect, Scopus, and esteemed publishers such as Elsevier, Springer, Frontiers, and Taylor & Francis. Considering that the majority of pharmacological studies were conducted on crude oils only, the extracted data were critically analyzed to gain further insight into the prospects of TTO being used as a neuroprotective agent by drug formulation or dietary supplement. In addition, the active constituents contributing to the activity of TTO have not been well justified, and the core mechanisms need to be unveiled especially for anti-inflammatory and immunomodulatory effects leading to neuroprotection. Therefore, this review attempts to correlate the anti-inflammatory and immunomodulatory activity of TTO with its neuroprotective mechanisms.
Tea Tree Oil/therapeutic use* ; Melaleuca ; Neuroprotection ; Drug Repositioning ; Neuroinflammatory Diseases ; Australia ; Oils, Volatile ; Anti-Inflammatory Agents/pharmacology*

OBJECTIVES: To study the effect of early use of sodium valproate on neuroinflammation after traumatic brain injury (TBI). METHODS: A total of 45 children who visited in Xuzhou Children's Hospital Affiliated to Xuzhou Medical University from August 2021 to August 2022 were enrolled in this prospective study, among whom 15 healthy children served as the healthy control group, and 30 children with TBI were divided into a sodium valproate treatment group and a conventional treatment group using a random number table (n=15 each). The children in the sodium valproate treatment group were given sodium valproate in addition to conventional treatment, and those in the conventional group were given an equal volume of 5% glucose solution in addition to conventional treatment. The serum concentrations of nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3), high-mobility group box 1 (HMGB1), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) were measured in the healthy control group on the day of physical examination and in the children with TBI on days 1, 3, and 5 after admission. Glasgow Outcome Scale-Extended (GOS-E) score was evaluated for the children with TBI 2 months after discharge. RESULTS: Compared with the healthy control group, the children with TBI had significantly higher serum concentrations of NLRP3, HMGB1, TNF-α, and IL-1β on day 1 after admission (P<0.017). The concentration of NLRP3 on day 5 after admission was significantly higher than that on days 1 and 3 after admission in the children with TBI (P<0.017). On days 3 and 5 after admission, the sodium valproate treatment group had a significantly lower concentration of NLRP3 than the conventional treatment group (P<0.05). For the conventional treatment group, there was no significant difference in the concentration of HMGB1 on days 1, 3, and 5 after admission (P>0.017), while for the sodium valproate treatment group, the concentration of HMGB1 on day 5 after admission was significantly lower than that on days 1 and 3 after admission (P<0.017). On day 5 after admission, the sodium valproate treatment group had a significantly lower concentration of HMGB1 than the conventional treatment group (P<0.05). For the children with TBI, the concentration of TNF-α on day 1 after admission was significantly lower than that on days 3 and 5 after admission (P<0.017). On days 3 and 5 after admission, the sodium valproate treatment group had a significantly lower concentration of TNF-α than the conventional treatment group (P<0.05). The concentration of IL-1β on day 3 after admission was significantly lower than that on days 1 and 5 after admission (P<0.017) in the children with TBI. On days 3 and 5 after admission, the sodium valproate treatment group had a significantly lower concentration of IL-1β than the conventional treatment group (P<0.05). The GOS-E score was significantly higher in the sodium valproate treatment group than that in the conventional treatment group 2 months after discharge (P<0.05). CONCLUSIONS Early use of sodium valproate can reduce the release of neuroinflammatory factors and improve the prognosis of children with TBI.
Child ; Humans ; Valproic Acid/therapeutic use* ; HMGB1 Protein ; Pilot Projects ; Tumor Necrosis Factor-alpha ; Neuroinflammatory Diseases ; NLR Family, Pyrin Domain-Containing 3 Protein ; Prospective Studies ; Brain Injuries, Traumatic/pathology*

Humans ; Neuroinflammatory Diseases ; COVID-19/complications* ; Brain

Parkinson's disease (PD) is a common neurodegenerative disorder caused by the loss of dopamine neurons in the substantia nigra and the formation of Lewy bodies, which are mainly composed of alpha-synuclein fibrils. Alpha-synuclein plays a vital role in the neuroinflammation mediated by the nucleotide-binding oligomerization domain-, leucine-rich repeat-, and pyrin domain-containing protein 3 (NLRP3) inflammasome in PD. A better understanding of the NLRP3 inflammasome-mediated neuroinflammation and the related mitochondrial impairment during PD progression may facilitate the development of promising therapies for PD. This review focuses on the molecular mechanisms underlying NLRP3 inflammasome activation, comprising priming and protein complex assembly, as well as the role of mitochondrial impairment and its subsequent inflammatory effects on the progression of neurodegeneration in PD. In addition, the therapeutic strategies targeting the NLRP3 inflammasome for PD treatment are discussed, including the inhibitors of NLRP3 inflammatory pathways, mitochondria-focused treatments, microRNAs, and other therapeutic compounds.
Humans ; Parkinson Disease/complications* ; alpha-Synuclein ; Inflammasomes ; NLR Family, Pyrin Domain-Containing 3 Protein ; Neuroinflammatory Diseases ; Mitochondria

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*

As one of the most frequent complications of diabetes, diabetic neuropathy often involves peripheral and central nervous systems. Neuroinflammation is the key pathogenic factor of secondary nerve injury in diabetes. NOD-like receptor pyrin domain-containing 3(NLRP3) inflammasome is a group of subcellular multiprotein complexes, including NLRP3, apoptosis associated speck-like protein(ASC), and pro-cysteinyl aspartate specific proteinase 1(pro-caspase-1). NLRP3 inflammasome is an inducer of innate immune responses. Its activation stimulates the inflammatory cascade reaction, promotes the release of inflammatory mediators, triggers cell death and uncontrolled autophagy, activates glial cells, facilitates peripheral immune cell infiltration, and initiates amyoid β(Aβ)-tau cascade reactions. As a result, it contributes to the central nerve, somatic nerve, autonomic nerve, and retinal nerve cell damage secondary to diabetes. Therefore, due to its key role in the neuroinflammation responses of the body, NLRP3 inflammasome may provide new targets for the treatment of diabetic neuropathy. With multi-target and low-toxicity advantages, traditional Chinese medicine plays a vital role in the treatment of diabetic neuropathy. Accumulating evidence has shown that traditional Chinese medicine exerts curative effects on diabetic neuropathy possibly through regulating NLRP3 inflammasome. Although the role of NLRP3 inflammasome in diabetes and related complications has been investigated in the literature, systematical studies on drugs and mechanism analysis for secondary neuropathy are still lacking. In this article, the role of NLRP3 inflammasome in diabetic neuropathy was explored, and the research progress on traditional Chinese medicine in the treatment of diabetic neuropathy through NLRP3 inflammasome was reviewed.
Humans ; Inflammasomes/metabolism* ; NLR Family, Pyrin Domain-Containing 3 Protein/metabolism* ; Diabetic Neuropathies/drug therapy* ; Medicine, Chinese Traditional ; Neuroinflammatory Diseases ; Inflammation ; Diabetes Mellitus

This paper aimed to study the effect of Erjing Pills on the improvement of neuroinflammation of rats with Alzheimer's di-sease(AD) induced by the combination of D-galactose and Aβ_(25-35) and its mechanism. SD rats were randomly divided into a sham group, a model control group, a positive drug group(donepezil, 1 mg·kg~(-1)), an Erjing Pills high-dose group(9.0 g·kg~(-1)), and an Erjing Pills low-dose group(4.5 g·kg~(-1)), with 14 rats each group. To establish the rat model of AD, Erjing Pills were intragastrically administrated to rats for 5 weeks after 2 weeks of D-galactose injection. D-galactose was intraperitoneally injected into rats for 3 weeks, and then Aβ_(25-35) was injected into the bilateral hippocampus. The new object recognition test was used to evaluate the learning and memory ability of rats after 4 weeks of intragastric administration. Tissues were acquired 24 h after the last administration. The immunofluorescence method was used to detect the activation of microglia in the brain tissue of rats. The positive expressions of Aβ_(1-42) and phosphory protein Tau~(404)(p-Tau~(404)) in the CA1 area of the hippocampus were detected by immunohistochemistry. The levels of inflammatory factors interleukin-1β(IL-1β), tumor necrosis factor-α(TNF-α), and interleukin-6(IL-6) in the brain tissue were determined by enzyme-linked immunosorbent assay(ELISA). Toll-like receptor 4(TLR4)/nuclear factor kappa B(NF-κB)/nucleotide-binding oligomerization domain-like receptors 3(NLRP3) pathway-associated proteins in the brain tissue were determined by Western blot. The results showed that as compared with the sham group, the new object recognition index of rats in the model control group decreased significantly, the deposition of Aβ_(1-42) and p-Tau~(404) positive protein in the hippocampus increased significantly, and the levels of microglia activation increased significantly in the dentate gyrus. The levels of IL-1β, TNF-α, and IL-6 in the hippocampus of the model control group increased significantly, and the expression levels of TLR4, p-NF-κB p65/NF-κB p65, p-IκBα/IκBα, and NLRP3 proteins in the hippocampus increased significantly. Compared with the model control group, the Erjing Pill groups enhanced the new object recognition index of rats, decreased the deposition of Aβ_(1-42) and the expression of p-Tau~(404) positive protein in the hippocampus, inhibited the activation of microglia in the dentate gyrus, reduced the levels of inflammatory factors IL-1β, TNF-α, and IL-6 in the hippocampus, and down-regulated the expression levels of TLR4, p-NF-κB P65/NF-κB P65, p-IκBα/IκBα, and NLRP3 proteins in the hippocampus. In conclusion, Erjing Pills can improve the learning and memory ability of the rat model of AD presumably by improving the activation of microglia, reducing the expression levels of neuroinflammatory factors IL-1β, TNF-α, and IL-6, inhibiting the TLR4/NF-κB/NLRP3 neuroinflammation pathway, and decreasing hippocampal deposition of Aβ and expression of p-Tau, thereby restoring the hippocampal morphological structure.
Animals ; Rats ; Rats, Sprague-Dawley ; NF-kappa B ; NF-KappaB Inhibitor alpha ; NLR Family, Pyrin Domain-Containing 3 Protein ; Galactose ; Interleukin-6 ; Neuroinflammatory Diseases ; Toll-Like Receptor 4 ; Tumor Necrosis Factor-alpha

This study aimed to explore the potential mechanism of Berberis atrocarpa Schneid. anthocyanin against Alzheimer's disease(AD) based on network pharmacology, molecular docking technology, and in vitro experiments. Databases were used to screen out the potential targets of the active components of B. atrocarpa and the targets related to AD. STRING database and Cytoscape 3.9.0 were adopted to construct a protein-protein interaction(PPI) network and carry out topological analysis of the common targets. Gene Ontology(GO) and Kyoto Encyclopedia of Genes and Genomes(KEGG) enrichment analyses were performed on the target using the DAVID 6.8 database. Molecular docking was conducted to the active components and targets related to the nuclear factor kappa B(NF-κB)/Toll-like receptor 4(TLR4) pathway. Finally, lipopolysaccharide(LPS) was used to induce BV2 cells to establish the model of AD neuroinflammation for in vitro experimental validation. In this study, 426 potential targets of active components of B. atrocarpa and 329 drug-disease common targets were obtained, and 14 key targets were screened out by PPI network. A total of 623 items and 112 items were obtained by GO functional enrichment analysis and KEGG pathway enrichment analysis, respectively. Molecular docking results showed that NF-κB, NF-κB inhibitor(IκB), TLR4, and myeloid differentiation primary response 88(MyD88) had good binding abilities to the active components, and malvidin-3-O-glucoside had the strongest binding ability. Compared with the model group, the concentration of nitric oxide(NO) decreased at different doses of malvidin-3-O-glucoside without affecting the cell survival rate. Meanwhile, malvidin-3-O-glucoside down-regulated the protein expressions of NF-κB, IκB, TLR4, and MyD88. This study uses network pharmacology and experimental verification to preliminarily reveal that B. atrocarpa anthocyanin can inhibit LPS-induced neuroinflammation by regulating the NF-κB/TLR4 signaling pathway, thereby achieving the effect against AD, which provides a theoretical basis for the study of its pharmacodynamic material basis and mechanism.
NF-kappa B ; Alzheimer Disease ; Network Pharmacology ; Anthocyanins ; Berberis ; Lipopolysaccharides ; Molecular Docking Simulation ; Myeloid Differentiation Factor 88 ; Neuroinflammatory Diseases ; Toll-Like Receptor 4 ; I-kappa B Proteins