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CDK5 plays a crucial role in maintaining normal central nervous system (CNS) development and synaptic function, while microglia are the primary immune cells present in the CNS and play vital physiological roles in CNS development, immune surveillance, and regulation of synaptic plasticity. Despite this, our understanding of both the substrate proteins and functional mechanisms of CDK5 in microglia remains limited. To address this, we utilized CRISPR-Cas9 knockout of Cdk5 in BV2 cells and conducted quantitative phosphoproteomics analysis to systematically screen potential CDK5 substrates in microglia. Our findings identified 335 phosphorylation sites on 234 proteins as potential CDK5 substrates in microglia based on the reported sequence motif. Through in vitro kinase assay and intracellular inhibition and knockout of CDK5 experiments, we confirmed that ER proteins MTDH (protein LYRIC) and Calnexin are novel substrate proteins of CDK5. Moreover, we demonstrated for the first time a critical mechanism for regulating protein synthesis in microglia, that the phosphorylation of S565 site on MTDH, a key protein mediating cell growth, by CDK5 inhibits protein synthesis. Our data provide valuable insights for the discovery of new substrate proteins of CDK5 and the in-depth investigation of the function and mechanism of CDK5 in microglia., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Multiple sclerosis (MS) is an inflammatory demyelination neurodegenerative disease of the central nervous system (CNS). Ferroptosis has been implicated in a range of brain disorders, and iron-loaded microglia are frequently found in affected brain regions. However, the molecular mechanisms linking ferroptosis with MS have not been well-defined. The present study seeks to bridge this gap and investigate the impact of matrine (MAT), a herbal medicine with immunomodulatory capacities, on the regulation of oxidative stress and ferroptosis in the CNS of mice with experimental autoimmune encephalomyelitis (EAE), an animal model of MS. CNS of EAE mice contained elevated levels of ferroptosis-related molecules, e.g., MDA, LPCAT3 and PTGS2, but decreased expression of antioxidant molecules, including GSH and SOD, GPX4 and SLC7A11. This pathogenic process was reversed by MAT treatment, together with significant reduction of disease severity and CNS inflammatory demyelination. Furthermore, the expression of PTGS2 and LOX was largely increased in microglia of EAE mice, accompanied with increased production of IL-6 and TNF-α, indicating a proinflammatory phenotype of microglia that undergo oxidative stress/ferroptosis, and their expression was significantly reduced after MAT treatment. Together, our results indicate that ferroptosis/inflammation plays an important role in the pathogenesis of CNS autoimmunity, and inhibiting ferroptosis-induced microglial activation/inflammation could be a novel mechanism underlying the therapeutic effects of MAT on CNS inflammatory demyelination in EAE., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:LinZhu reports financial support was provided by National Natural Science Foundation of China. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Chronic pain is prevalent among aging adults. Epidemiologic evidence has demonstrated that individuals with chronic pain have accelerated memory decline and increased probability of dementia. Neurophysiologic, molecular, and pharmacologic hypotheses have been proposed to explain the relationship between chronic pain and cognitive decline, but there remains currently limited evidence supporting any of these. Here, we integrate multi-omic data across human cohorts and rodent species and demonstrate that methylation in the prefrontal cortex induced by chronic pain specifically targets transcriptional networks associated with cognitive ability, memory, and Alzheimer's disease in humans. We validate this with multiple independent data sets and identify cortical microglia as a likely mechanism by which chronic pain can increase dementia risk. Our analyses support the molecular hypothesis for the role of chronic pain in cognitive decline and identifies several potential therapeutic targets., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 International Brain Research Organization (IBRO). Published by Elsevier Inc. All rights reserved.)

Microinfarcts are widespread in the elderly, accompanied by varying degrees of cognitive decline. Continuous theta burst stimulation (cTBS) has been demonstrated to be neuroprotective on cognitive dysfunction, but the underlying cellular mechanism has been still not clear. In the present study, we evaluated the effects of cTBS on cognitive function and brain pathological changes in mice model of microinfarcts. The spatial learning and memory was assessed by Morris water maze (MWM), Glymphatic clearance efficiency was evaluated using in vivo two-photon imaging. The loss of neurons, activation of astrocytes and microglia, the expression and polarity distribution of the astrocytic aquaporin-4 (AQP4) were assessed by immunofluorescence staining. Our results showed that cTBS treatment significantly improved the spatial learning and memory, accelerated the efficiency of glymphatic clearance, up-regulated the AQP4 expression and improved the polarity distribution of AQP4 in microinfarcts mice. Besides, cTBS treatment increased the number of surviving neurons, whereas decreased the activated astrocytes and microglia. Our study suggested that cTBS accelerated glymphatic clearance and inhibited the excessive gliogenesis, which ultimately exerted neuroprotective effects on microinfarcts mice., (Copyright © 2024 International Brain Research Organization (IBRO). Published by Elsevier Inc. All rights reserved.)

The neuroinflammatory response promotes secondary brain injury after traumatic brain injury (TBI). Triggering receptor expressed on myeloid cells 1 (TREM1) is a key regulator of inflammation. However, the role of TREM1 in TBI is poorly studied. The purpose of this study was to investigate the role of TREM1 in TBI and the possible underlying mechanism. We found that the protein expression of TREM1 significantly increased after TBI in rats, and the TREM1 protein localized to microglia. Inhibition of the TREM1 protein with LP17 significantly blocked ERK phosphorylation and reduced cytoplasmic phospholipase A2 (cPLA2) protein expression and phosphorylation. In addition, LP17-mediated TREM1 inhibition significantly reduced the protein expression of iNOS and increased the protein expression of Arg1. Moreover, after TREM1 was inhibited, the secretion of the proinflammatory factors TNF-α and IL-1β was significantly reduced, while the secretion of the anti-inflammatory factors IL-4 and IL-10 was significantly increased. Additionally, inhibition of TREM1 by LP17 significantly reduced neuronal apoptosis and ameliorated nerve dysfunction in TBI model rats. In conclusion, our findings suggest that TREM1 enhances neuroinflammation and promotes neuronal apoptosis after TBI, and these effects may be partly mediated via the ERK/cPLA2 signalling pathway., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 International Brain Research Organization (IBRO). Published by Elsevier Inc. All rights reserved.)

Microglia, the resident immune cells of the central nervous system, emerge in the brain during early embryonic development and persist throughout life. They play essential roles in brain homeostasis, and their dysfunction contributes to neuroinflammation and the progression of neurodegenerative diseases. Recent studies have uncovered an intricate relationship between microglia functions and metabolic processes, offering fresh perspectives on disease mechanisms and possible treatments. Despite these advancements, there are still significant gaps in our understanding of how metabolic dysregulation affects microglial phenotypes in these disorders. This review aims to address these gaps, laying the groundwork for future research on the topic. We specifically examine how metabolic shifts in microglia, such as the transition from oxidative phosphorylation and mitochondrial metabolism to heightened glycolysis during proinflammatory states, impact the disease progression in Alzheimer's disease, multiple sclerosis, Parkinson's disease, amyotrophic lateral sclerosis, and Huntington's disease. Additionally, we explore the role of iron, fatty and amino acid metabolism in microglial homeostasis and repair. Identifying both distinct and shared metabolic adaptations in microglia across neurodegenerative diseases could reveal common therapeutic targets and provide a deeper understanding of disease-specific mechanisms underlying multiple CNS disorders., Competing Interests: Declarations Ethics approval and consent to participate Not applicable. Consent for publication Not applicable. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

CNS Drug discovery has been challenging due to the lack of clarity on CNS diseases' basic biological and pathological mechanisms. Despite the difficulty, some CNS drugs have been developed based on phenotypic effects. Herein, we propose a phenotype-structure relationship model, which predicts an anti-neuroinflammatory potency based on 3D molecular structures of the phenotype-active or inactive compounds without specifying targets. For this chemo-centric study, a predictive model of the nitric oxide (NO) inhibitory potency in hyper-activated microglia is built from the 548 agents, which were collected from 95 research articles (28 substructures consisting of natural products and synthetic scaffolds) and doubly externally validated by the agents of 9 research articles as third set. 3D Structures (multi-conformer ensemble) of every agent were encoded into the E3FP molecular fingerprint of the Keiser group as a 3D molecular representation. The location information of the molecular fingerprints could be learned and validated to classify the inhibitory potency of compounds (IC 50 cut-off between the active and inactive: 37.1 µM): (1) multi-layer perceptron (MLP) (AUC- CV : 0.997, AUC- Test : 0.992), (2) recurrent neural network (RNN) (AUC- CV : 0.999, AUC- Test : 0.995), and (3) convolutional neural network (CNN) (AUC- CV : 0.998, AUC- Test : 0.994). The high performance of these models was compared with that of four classical machine classification models (Logistic, Ridge, Lasso, and Naïve Bayes). We named the binary classification models NO-Classifier. Independent test set validation and decision region analysis of the independent test set doubly demonstrated NO-Classifier effectively discerned the anti-inflammatory potency of testing compounds in inflammatory cell phenotype with the webserver in https://no-classifier.onrender.com., Competing Interests: Declarations Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Background: Cirsilineol is a trimethoxy and dihydroxy flavonoid isolated from plant species such as Artemisia vestita and has a variety of pharmacological properties. This study analyzed whether cirsilineol could prevent postoperative cognitive dysfunction (POCD)., Methods: A POCD mouse model induced by anesthesia/surgery induction and a cell model established with hydrogen peroxide (H 2 O 2 )-induced microglia BV-2 were employed to explore the efficacy of cirsilineol on POCD. The cognition function of the mice were assessed by carrying out behavioral tests (Morris water maze test and Y-maze test). We assessed the activation and polarization status of microglia using immunofluorescence analysis and detected the expression levels of CD86 and CD206 using the quantitative PCR (qPCR). Subsequently, cell viability was determined by CCK-8 assay and apoptosis was assessed using Calcein-AM/PI staining. Meanwhile, superoxide dismutase (SOD) and malondialdehyde (MDA) levels in plasma and cell culture medium were detected using chemiluminescence. Finally, the phosphorylation levels of JAK/STAT signaling pathway-related proteins were analyzed by Western blot., Results: Cirsilineol reduced the escape latency and times of crossing island and increased spontaneous alternation (SA) rate, restoring the cognitive dysfunctions of POCD-modeled mice. Meanwhile, POCD elevated CD86 expression and malondialdehyde content and lowered the level of SOD; however, cirsilineol promoted CD206 expression and generation of SOD and inhibited malondialdehyde production. In H 2 O 2 -induced microglia BV-2, cirsilineol treatment increased SOD content and suppressed the generation of reactive oxygen species (ROS) and malondialdehyde, modulating microglia M1/M2 polarization and JAK/STAT pathway., Conclusion: Cirsilineol prevented against POCD by attenuating oxidative stress and modulating microglia M1/M2 polarization, providing novel insights for the management of POCD., Competing Interests: The authors declare that they have no competing interests., (© 2024 Du et al.)

Recent studies have highlighted the importance of microglia, the resident macrophages in the brain, in regulating cognitive functions such as learning and memory in both healthy and diseased states. However, there are conflicting results and the underlying mechanisms are not fully understood. In this study, we examined the effect of depleting adult microglia on spatial learning and memory under both physiological conditions and lipopolysaccharide (LPS)-induced neuroinflammation. Our results revealed that microglial depletion by PLX5622 caused mild spatial memory impairment in mice under physiological conditions; however, it prevented memory deficits induced by systemic LPS insult. Inactivating microglia through minocycline administration replicated the protective effect of microglial depletion on LPS-induced memory impairment. Furthermore, our study showed that PLX5622 treatment suppressed LPS-induced neuroinflammation, microglial activation, and synaptic dysfunction. These results strengthen the evidence for the involvement of microglial immunoactivation in LPS-induced synaptic and cognitive malfunctions. They also suggest that targeting microglia may be a potential approach to treating neuroinflammation-associated cognitive dysfunction seen in neurodegenerative diseases., Competing Interests: The authors declare that they have no competing interests., (© 2024 Zong et al.)

The mechanisms through which systemic inflammation exerts its effect on the central nervous system (CNS) are still not completely understood. Exosomes are small (30 to 100 nm) membrane-bound extracellular vesicles released by most of the mammalian cells. Exosomes play a vital role in cell-to-cell communication. This includes regulation of inflammatory responses by shuttling mRNAs, miRNAs, and cytokines, both locally and systemically to the neighboring as well as distant cells to further modulate the transcriptional and/or translational states and affect the functional phenotype of those cells that have taken up these exosomes. The role of circulating blood exosomes leading to neuroinflammation during systemic inflammatory conditions was hereby characterized. Serum-derived exosomes from LPS-challenged mice (SDEL) were freshly isolated from the sera of the mice that were earlier treated with LPS and used to study the effects on neuroinflammation. Exosomes isolated from the sera of the mice injected with saline were used as a control. In-vitro studies showed that the SDEL upregulate pro-inflammatory cytokine gene expression in the murine cell lines of microglia (BV-2), astrocytes (C8-D1A), and cerebral microvascular endothelial cells (bEnd.3). To further study their effects in-vivo, SDEL were intravenously injected into normal adult mice. Elevated mRNA expression of pro-inflammatory cytokines was observed in the brains of SDEL recipient mice. Proteomic analysis of the SDEL confirmed the increased expression of inflammatory cytokines in them. Together, these results demonstrate and strengthen the novel role of peripheral circulating exosomes in causing neuroinflammation during systemic inflammatory conditions., Competing Interests: Declarations Ethics approval and consent to participate Not applicable. Consent for publication All the authors read and approved the final manuscript for publication. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Secondary neurological impairment mediated by neuroinflammation is recognized as a crucial pathological factor in central nervous system (CNS) diseases. Currently, there exists a lack of specific therapies targeting neuroinflammation. Given that microglia constitute the primary immune cells involved in the neuroinflammatory response, a thorough comprehension of their role in CNS diseases is imperative for the development of efficacious treatments. Recent investigations have unveiled the significance of formyl peptide receptors (FPRs) in various neuroinflammatory diseases associated with microglial overactivation. Consequently, FPRs emerge as promising targets for modulating the neuroinflammatory response. This review aims to comprehensively explore the therapeutic potential of targeting FPRs in the management of microglia-mediated neuroinflammation. It delineates the molecular characteristics and functions of FPRs, elucidates their involvement in the inflammatory response linked to microglial overactivation, and synthesizes therapeutic strategies for regulating microglia-mediated neuroinflammation via FPR modulation, thereby charting a novel course for the treatment of neuroinflammatory diseases., (© 2024 Federation of American Societies for Experimental Biology.)

Mutations in ITM2B cause familial British, Danish, Chinese, and Korean dementias. In familial British dementia (FBD), a mutation in the stop codon of the ITM2B gene (also known as BRI2) causes a C-terminal cleavage fragment of the ITM2B/BRI2 protein to be extended by 11 amino acids. This fragment, termed amyloid-Bri (ABri), is highly insoluble and forms extracellular plaques in the brain. ABri plaques are accompanied by tau pathology, neuronal cell death and progressive dementia, with striking parallels to the aetiology and pathogenesis of Alzheimer's disease. The molecular mechanisms underpinning FBD are ill-defined. Using patient-derived induced pluripotent stem cells, we show that expression of ITM2B/BRI2 is 34-fold higher in microglia than neurons and 15-fold higher in microglia compared with astrocytes. This cell-specific enrichment is supported by expression data from both mouse and human brain tissue. ITM2B/BRI2 protein levels are higher in iPSC-microglia compared with neurons and astrocytes. The ABri peptide was detected in patient iPSC-derived microglial lysates and conditioned media but was undetectable in patient-derived neurons and control microglia. The pathological examination of post-mortem tissue supports the presence of ABri in microglia that are in proximity to pre-amyloid deposits. Finally, gene co-expression analysis supports a role for ITM2B/BRI2 in disease-associated microglial responses. These data demonstrate that microglia are major contributors to the production of amyloid forming peptides in FBD, potentially acting as instigators of neurodegeneration. Additionally, these data also suggest ITM2B/BRI2 may be part of a microglial response to disease, motivating further investigations of its role in microglial activation. These data have implications for our understanding of the role of microglia and the innate immune response in the pathogenesis of FBD and other neurodegenerative dementias including Alzheimer's disease., Competing Interests: Declarations Conflict of interest The authors declare no competing interests., (© 2024. The Author(s).)

Astrocytes derive from different lineages and play a critical role in neuropathic pain after spinal cord injury (SCI). Whether selectively eliminating these main origins of astrocytes in lumbar enlargement could attenuate SCI-induced neuropathic pain remains unclear. Through transgenic mice injected with an adeno-associated virus vector and diphtheria toxin, astrocytes in lumbar enlargement were lineage traced, targeted, and selectively eliminated. Pain-related behaviors were measured with an electronic von Frey apparatus and a cold/hot plate after SCI. RNA sequencing, bioinformatics analysis, molecular experiment, and immunohistochemistry were used to explore the potential mechanisms after astrocyte elimination. Lineage tracing revealed that the resident astrocytes but not ependymal cells were the main origins of astrocytes-induced neuropathic pain. SCI-induced mice to obtain significant pain symptoms and astrocyte activation in lumbar enlargement. Selective resident astrocyte elimination in lumbar enlargement could attenuate neuropathic pain and activate microglia. Interestingly, the type I interferons (IFNs) signal was significantly activated after astrocytes elimination, and the most activated Gene Ontology terms and pathways were associated with the type I IFNs signal which was mainly activated in microglia and further verified in vitro and in vivo. Furthermore, different concentrations of interferon and Stimulator of interferon genes (STING) agonist could activate the type I IFNs signal in microglia. These results elucidate that selectively eliminating resident astrocytes attenuated neuropathic pain associated with type I IFNs signal activation in microglia. Targeting type I IFNs signals is proven to be an effective strategy for neuropathic pain treatment after SCI., Competing Interests: QZ, YZ, YR, LZ, JZ, SY, HN, RZ, LC, NX No competing interests declared, (© 2024, Zhao, Zhu, Ren et al.)

Approximately 50% of patients with chronic neuropathic pain experience cognitive impairment, which negatively impacts their quality of life. The cannabinoid type 2 receptor (CB2R) may be involved in hippocampal cognitive processes. However, its role in chronic neuropathic pain-induced cognitive impairment remains elusive. Spared nerve injury (SNI) was used to induce chronic neuropathic pain in rats, while the novel-object recognition test and the Y-maze test were employed to assess cognitive function. Immunofluorescence, western blotting, and stereotaxic hippocampal microinjection were utilized to elucidate the potential mechanisms. We observed a reduction in mechanical pain threshold and cognitive impairment in SNI rats. This was accompanied by a tendency for hippocampal microglia to adopt pro-inflammatory functions. Notably, no changes were detected in CB2R expression. However, downregulation of the endogenous ligands AEA and 2-AG was evident. Hippocampal microinjection of a CB2R agonist mitigated cognitive impairment in SNI rats, which correlated with a tendency for microglia to adopt anti-inflammatory functions. Additionally, SNI-induced activation of the p-ERK/NFκB pathway in the hippocampus. Activation of CB2R reversed this process by upregulating DUSP6 expression in microglia. The effects elicited by CB2R activation could be inhibited through the downregulation of microglial DUSP6 via hippocampal adeno-associated virus (AAV) microinjection. Conversely, overexpression of hippocampal DUSP6 using AAV ameliorated the cognitive deficits observed in SNI rats, which remained unaffected by the administration of a CB2R antagonist. Our findings demonstrate that activation of hippocampal CB2R can mitigate chronic neuropathic pain-induced cognitive impairment through the modulation of the DUSP6/ERK/NFκB pathway., (© 2024 Federation of American Societies for Experimental Biology.)

Aims: Alzheimer's disease (AD) is characterized by β-amyloid (Aβ) aggregation and neuroinflammation, leading to progressive synaptic loss and cognitive decline. Recent evidence suggests that Galectin-3 (Gal-3) plays a critical role in Aβ pathogenesis. However, strategies to simultaneously target Gal-3 and Aβ are currently insufficient. This study evaluates the therapeutic efficacy of (E)-2-(3,4-dihydroxystyryl)-3-hydroxy-4H-pyran-4-one (D30), in reducing Gal-3 and Aβ pathogenesis., Materials and Methods: We applied exogenous oligomeric Aβ and used 5 × FAD mice to assess the impact of Aβ on Gal-3 deposition, microglial activation, and cognitive function. Thy1-EGFP mice were employed to observe dendritic spines. Comprehensive evaluations of D30's effects included behavioral studies, transcriptomic analysis, Western blotting, and immunofluorescent staining. The interaction between D30 and Gal-3 was examined using fluorescence resonance energy transfer (FRET) and microscale thermophoresis (MST)., Key Findings: D30 effectively reduced Aβ monomer production by inhibiting Amyloid Precursor Protein (APP) and presenilin 1 (PS1) expression, and decreased Aβ aggregation. Treatment with D30 improved cognitive functions, reversed dendritic spine loss, and increased PSD95 expression in 5 × FAD mice. Additionally, D30 significantly lowered Gal-3 levels in both plasma and hippocampal tissues. D30 binds to Gal-3 and disrupts the interaction between Gal-3 and TREM2, as confirmed by FRET and MST., Significance: Our findings underscore the interaction between Gal-3 and Aβ in AD and its role in systemic inflammation using the 5 × FAD mouse model. Being able to target and regulate Gal-3 together with Aβ is crucial for preventing neuroinflammation and protecting synapses, D30 emerged as a novel compound with promising potential for AD treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

Microglia-mediated neuroinflammation is critical in the pathogenesis of sepsis-associated encephalopathy(SAE). Identifying the key factors that inhibit microglia-mediated neuroinflammation holds promise as a potential target for preventing and treating SAE. Esketamine, a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist, has been proposed to possess protective and therapeutic properties against neuroinflammatory disorders. This study provides evidence that the administration of Esketamine in SAE mice improves cognitive impairments and alleviates neuronal damage by inhibiting the microglia-mediated neuroinflammation. The BDNF receptor antagonist K252a was employed in both vivo and in vitro experiments. The findings indicate that K252a successfully counteracted the beneficial effects of Esketamine on microglia and cognitive behavior in mice with SAE. Consequently, these results suggest that Esketamine inhibits microglia-mediated neuroinflammation by activating the BDNF pathway, and mitigating neuronal damage and cognitive dysfunction associated with SAE., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Tumor-associated microglia and macrophages (TAM) make up the largest immune cell population in the glioblastoma (GBM) tumor microenvironment. Given the heterogeneity and plasticity of TAMs in the GBM tumor microenvironment, understanding the context-dependent cancer cell-TAM symbiotic interaction is crucial for understanding GBM biology and developing effective therapies. In a recent issue of Cell, Kloosterman and colleagues identified a subpopulation of glycoprotein nonmetastatic melanoma protein Bhigh lipid-laden microglia and macrophages (LLM) in GBM. Mesenchymal-like GBM cells help generate the LLM phenotype. Reciprocally, LLMs are epigenetically rewired to recycle myelin and transfer the lipid from myelin to cancer cells, fueling mesenchymal-like GBM progression in a liver X receptor/ABCA1-dependent manner. Together, leveraging LLMs opens new therapeutic possibilities for rewiring the metabolism-mediated tumor-TAM interaction during GBM progression., (©2024 American Association for Cancer Research.)

Aims: Microglia activation after spinal cord injury (SCI) is a double-edged sword, modulation of the activated microglia populations toward pro-regenerative phenotypes highlights the potential therapeutic implications. P2Y12, a microglia-specific marker, remains underexplored in its capacity to polarize microglial activation populations in SCI repair. We aimed to explore the effects of modulating P2Y12 on microglia function after spinal cord injury, and further on axonal regeneration and motor recovery after spinal cord injury., Materials and Methods: The study employed both in vitro and in vivo models, using BV2 cells and a mouse model of SCI, respectively. Ticagrelor, a P2Y12 antagonist, was administered via a collagen scaffold to ensure stable and sustained release. Transcriptome sequencing analysis, immunofluorescence staining, and Basso Mouse Scale (BMS) scores were used to assess microglial activation, axonal regeneration, and functional recovery., Key Findings: Herein, we observed P2Y12 + microglia localized predominantly at the lesion periphery within 3 days post injury (dpi), manifesting a pro-inflammatory phenotype, but not anti-inflammatory phenotype. In vitro investigations revealed that P2Y12 inhibition of the activated microglia curtailed pro-inflammatory differentiation while augmenting anti-inflammatory differentiation., Significance: Leveraging this insight, we engineered a collagen scaffold-based delivery system for sustained release of the P2Y12 antagonist, ticagrelor, at the injury site in a mouse complete SCI model. Notably, P2Y12 suppression markedly enhanced axonal regeneration within the injured site and ameliorated lower limb motor functions in SCI mice. Collectively, our findings illuminate P2Y12-targeted microglial modulation as a promising therapeutic approach for SCI., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Galectin-9 (Gal-9) is a multifaceted regulator of various pathophysiologic processes that exerts positive or negative effects in a context-dependent manner. In this study, we elucidated the distinctive functional properties of Gal-9 on myeloid cells within the brain tumor microenvironment (TME). Gal-9-expressing cells were abundant at the hypoxic tumor edge in the tumor-bearing ipsilateral hemisphere compared with the contralateral hemisphere in an intracranial mouse brain tumor model. Gal-9 was highly expressed in microglia and macrophages in tumor-infiltrating cells. In primary glia, both the expression and secretion of Gal-9 were influenced by tumors. Analysis of a human glioblastoma bulk RNA sequencing dataset and a single-cell RNA sequencing dataset from a murine glioma model revealed a correlation between Gal-9 expression and glial cell activation. Notably, the Gal-9high microglial subset was functionally distinct from the Gal-9neg/low subset in the brain TME. Gal-9high microglia exhibited properties of inflammatory activation and higher rates of cell death, whereas Gal-9neg/low microglia displayed a superior phagocytic ability against brain tumor cells. Blockade of Gal-9 suppressed tumor growth and altered the activity of glial and T cells in a mouse glioma model. Additionally, glial Gal-9 expression was regulated by hypoxia-inducible factor-2α in the hypoxic brain TME. Myeloid-specific hypoxia-inducible factor-2α deficiency led to attenuated tumor progression. Together, these findings reveal that Gal-9 on myeloid cells is an immunoregulator and putative therapeutic target in brain tumors. Significance: Galectin-9 serves as an immune checkpoint molecule that modulates the functional properties of microglia in the brain tumor microenvironment and could potentially be targeted to effectively treat brain tumors., (©2024 American Association for Cancer Research.)

Depression is a serious mental disorder that threatens patients' physical and mental health worldwide. The activation of the NLR family pyrin domain-containing 3 (NLRP3) inflammasome is essential for microglia-mediated neuroinflammation and neuronal damage in depression. Numerous pathophysiological factors, such as mitochondrial dysfunction and impaired mitophagy, have an essential role in activating the NLRP3 inflammasome. AdipoRon is a potent adiponectin receptor agonist; however, its antidepressant effects have not been thoroughly investigated. In this study, we found that AdipoRon ameliorated depression-like behavior and neuronal damage induced by chronic unpredictable mild stress (CUMS). Further research demonstrated that AdipoRon inhibited the activation of the NLRP3 inflammasome and protected hippocampal neurons from microglial cytotoxicity by promoting mitophagy, increasing the clearance of damaged mitochondria, and reducing mtROS accumulation. Importantly, inhibition of mitophagy attenuated the antidepressant and neuroprotective effects of AdipoRon. Overall, these findings indicate that AdipoRon alleviates depression by inhibiting NLRP3 inflammasome activation in microglia via improving mitophagy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Cerebral ischemia-reperfusion injury (CI/RI) is a leading cause of disability and mortality worldwide, with limited therapeutic options available. Erianin, a natural compound derived from traditional Chinese medicine, has been reported to possess anti-inflammatory and neuroprotective properties. This study aimed to investigate the therapeutic potential of Erianin in CI/RI and elucidate its underlying mechanisms. Network pharmacology analysis predicted that Erianin could target the PI3K/AKT pathway, which are closely associated with CI/RI. In vivo experiments using a rat model of CI/RI demonstrated that Erianin treatment significantly alleviated neurological deficits, reduced infarct volume, and attenuated neuronal damage. Mechanistically, Erianin inhibited microglial cell polarization towards the pro-inflammatory M1 phenotype, as evidenced by the modulation of specific markers. Furthermore, Erianin suppressed the expression of pro-inflammatory cytokines and mediators, such as TNF-α, IL-6, and COX-2, while enhancing the production of anti-inflammatory factors, including Arg1, CD206, IL-4 and IL-10. In vitro studies using oxygen-glucose deprivation/reoxygenation (OGD/R)-stimulated microglial cells corroborated the anti-inflammatory and anti-apoptotic effects of Erianin. Notably, Erianin inhibited the NF-κB signaling pathway by inhibiting p65 phosphorylation and preventing the nuclear translocation of the p65 subunit. Collectively, these findings suggest that Erianin represents a promising therapeutic candidate for CI/RI by targeting microglial cell polarization and inflammation., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Pyruvate kinase M2 (PKM2) is a key metabolic enzyme. Yet, its role in cerebral ischemia injury remains unclear. In this study we demonstrated that PKM2 expression was increased in the microglia after mouse cerebral ischemia-reperfusion (I/R) injury. We found that microglial polarization-mediated pro-inflammatory effect was mediated by PKM2 after cerebral I/R. Mechanistically, our results revealed that nuclear PKM2 mediated ischemia-induced microglial polarization through association with acetyl-H3K9. Hif-1α mediated the effect of nuclear PKM2/histone H3 on microglial polarization. PKM2-dependent Histone H3/Hif-1α modifications contributed the expression of CCL2 and induced up-regulation of microglial polarization in peri-infarct, resulting in neuroinflammation. Inhibiting nuclear translocation of microglial PKM2 reduced ischemia-induced pro-inflammation and promoted neuronal survival. Together, this study identifies nucleus PKM2 as a crucial mediator for regulating ischemia-induced neuroinflammation, suggesting PKM2 as a potential therapeutic target in ischemic stroke., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: High fructose consumption increases blood pressure through microglia-related neuroinflammation in rats. Since intermediate-conductance calcium-activated potassium channels (KCa3.1) potentiates microglial reactivity, we examined whether the pretreatment with the KCa3.1 channel blocker TRAM-34 or minocycline prevents hypertension development in fructose-fed rats., Methods: The study involved male Wistar rats that were given either high fructose (10% in drinking water) or tap water for 21 days. Fructose groups also received minocycline or TRAM-34 systemically for 21 days. We measured systolic and diastolic blood pressure (SBP and DBP), heart rate (HR) periodically with tail-cuff; proinflammatory cytokines, and insulin levels in plasma via Enzyme-linked immunosorbent assay (ELISA), and neuroinflammatory markers in the nucleus tractus solitarii (NTS) by qPCR at the end of 21 days. We also examined endothelium-dependent hyperpolarization (EDH)-type vasorelaxations in isolated mesenteric arteries of the rats ex vivo., Results: SBP, DBP, and HR increased in the fructose group. Both minocycline and TRAM-34 significantly prevented these increases. Fructose intake also increased plasma interleukin-6, interleukin-1β, tumor necrosis factor-α, and insulin levels, whereas pretreatment with TRAM-34 prevented these increases as well. Iba-1, but not cluster of differentiation-86 levels were significantly higher in the NTS samples of fructose-fed hypertensive rats which implied microglial proliferation. EDH-type vasorelaxations mediated by endothelial KCa3.1 attenuated in the fructose group; however, TRAM-34 did not cause further deterioration in the relaxations., Conclusions: TRAM-34 is as effective as minocycline in preventing fructose-induced hypertension without interfering with EDH-type vasodilation. Furthermore, TRAM-34 relieves high fructose-associated systemic inflammation., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Journal of Hypertension, Ltd. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Alzheimer's disease (AD) is a neurodegenerative disorder that is difficult to cure and of global concern. Neuroinflammation is closely associated with the onset and progression of AD, making its treatment increasingly important. Compounds from natural products, with fewer side effects than synthetic drugs, are of high research interest. STAT3, a multifunctional transcription factor, is involved in various cellular processes including inflammation, cell growth, and apoptosis. Its activation and inhibition can have different effects under various pathological conditions. In AD, the STAT3 protein plays a crucial role in promoting neuroinflammation and contributing to disease progression. This occurs primarily through the JAK2-STAT3 signaling pathway, which impacts microglia, astrocytes, and hippocampal neurons. This paper reviews the STAT3 signaling pathway in AD and 25 compounds targeting STAT3 up to 2024. Notably, Rutin, Paeoniflorin, and Geniposide up-regulate STAT3 in hippocampal and cortex neurons, showing neuroprotective effects in various AD models. Other 23 compounds downregulate AD by suppressing neuroinflammation through inhibition of STAT3 activation in microglia and astrocytes. These findings highlight the potential of compounds from natural products in improving AD by targeting STAT3, offering insights into the prevention and management of AD., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: While a number of anesthetics has been shown potentially associated with neurotoxicity in the developing brain, dexmedetomidine, a drug that was rather recently introduced into the perioperative setting, is considered beneficial from neurological wellbeing. However, the underlying mechanism of how dexmedetomidine affects brain health remains to be determined. Based on our recent study, we hypothesized that dexmedetomidine would directly bind to and inhibit Toll-like receptor 4 (TLR4), a critical receptor largely expressed in microglia and responsible for neurological insult., Methods: We used TLR4 reporter assays to test if dexmedetomidine attenuates TLR4 activation. Furthermore, a direct binding of dexmedetomidine on TLR4 was tested using photoactivatable medetomidine. Lastly, the effect of dexmedetomidine on ketamine (anesthetic)-induced neurotoxicity was tested in rat pups (P7)., Results: We showed that dexmedetomidine attenuated TLR4 activation using reporter assay (IC 50  = 5.8 µg/mL). Photoactivatable dexmedetomidine delineated its direct binding sites on TLR4. We also showed that dexmedetomidine attenuated microglia activation both in vitro and in vivo., Discussion: We proposed a novel mechanism of dexmedetomidine-mediated neuroprotection., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

A large portion of neuropathic pain suffering patients may also concurrently experience neuropathic itch, with a negative impact on the quality of life. The limited understanding of neuropathic itch and the low efficacy of current anti-itch therapies dictate the urgent need of a better comprehension of molecular mechanisms involved and development of relevant animal models. This study was aimed to characterize the itching phenotype in a model of trauma-induced peripheral neuropathy, the spared nerve injury (SNI), and the molecular events underlying the overlap with the nociceptive behavior. SNI mice developed hyperknesis and spontaneous itch 7-14 days after surgery that was prevented by gabapentin treatment. Itch was associated with pain hypersensitivity, loss of intraepidermal nerve fiber (IENF) density and increased epidermal thickness. In coincidence with the peak of scratching behavior, SNI mice showed a spinal overexpression of IBA1 and GFAP, microglia and astrocyte markers respectively. An increase of the itch neuropeptide B-type natriuretic peptide (BNP) in NeuN+ cells, of its downstream effector interleukin 17 (IL17) along with increased pERK1/2 levels occurred in the spinal cord dorsal horn and DRG. A raise in BNP and IL17 was also detected at skin level. Stimulation of HaCat cells with conditioned medium from BV2-stimulated SH-SY5Y cells produced a dramatic reduction of HaCat cell viability. This study showed that SNI mice might represent a model for neuropathic itch and pain. Collectively, our finding suggest that neuropathic itch might initiate at spinal level, then affecting skin epidermis events, through a glia-mediated neuroinflammation-evoked BNP/IL17 mechanism., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to declare., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The decline of microglia in the dentate gyrus is a new phenomenon that may explain the pathogenesis of depression, and reversing this decline has an antidepressant effect. The development of strategies that restore the function of dentate gyrus microglia in under stressful conditions is becoming a new focus. Lymphocyte-activating gene-3 (LAG3) is an immune checkpoint expressed by immune cells including microglia. One of its functions is to suppress the expansion of immune cells. In a recent study, chronic systemic administration of a LAG3 antibody that readily penetrates the brain was reported to reverse chronic stress-induced hippocampal microglia decline and depression-like behaviors. We showed here that a single intranasal infusion of a LAG3 antibody (In-LAG3 Ab) reversed chronic unpredictable stress (CUS)-induced depression-like behaviors in a dose-dependent manner, which was accompanied by an increase in brain-derived neurotrophic factor (BDNF) in the dentate gyrus. Infusion of an anti-BDNF antibody into the dentate gyrus, construction of knock-in mice with the BDNF Val68Met allele, or treatment with the BDNF receptor antagonist K252a abolished the antidepressant effect of In-LAG3 Ab. Activation of extracellular signal-regulated kinase1/2 (ERK1/2) is required for the reversal effect of In-LAG3 Ab on CUS-induced depression-like behaviors and BDNF decrease in the dentate gyrus. Moreover, both inhibition and depletion of microglia prevented the reversal effect of In-LAG3 Ab on CUS-induced depression-like behaviors and impairment of ERK1/2-BDNF signaling in the dentate gyrus. These results suggest that In-LAG3 Ab exhibits an antidepressant effect through microglia-mediated activation of ERK1/2 and synthesis of BDNF in the dentate gyrus., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The aging of the central nervous system(CNS) is a primary contributor to neurodegenerative diseases in older individuals and significantly impacts their quality of life. Neuroinflammation, characterized by activation of microglia(MG) and release of cytokines, is closely associated with the onset of these neurodegenerative diseases. The activated status of MG is modulated by specifically programmed metabolic changes under various conditions. Succinylation, a novel post-translational modification(PTM) mainly involved in regulating mitochondrial energy metabolism pathways, remains unknown in its role in MG activation and aging. In the present study, we found that succinylation levels were significantly increased both during aging and upon lipopolysaccharide-induced(LPS-induced) MG activation undergoing metabolic reprogramming. Up-regulated succinylation induced by sirtuin 5 knockdown(Sirt5 KD) in microglial cell line BV2 resulted in significant up-regulation of aging-related genes, accompanied by impaired mitochondrial adaptability and a shift towards glycolysis as a major metabolic pathway. Furthermore, after LPS treatment, Sirt5 KD BV2 cells exhibited increased generation of reactive oxygen species(ROS), accumulation of lipid droplets, and elevated levels of lipid peroxidation. By employing immunoprecipitation, introducing point mutation to critical succinylation sites, and conducting enzyme activity assays for succinate dehydrogenase(SDH) and trifunctional enzyme subunit alpha(ECHA), we demonstrated that succinylation plays a regulatory role in modulating the activities of these mitochondrial enzymes. Finally, down-regulation the succinylation levels achieved through administration of succinyl phosphonate(SP) led to amelioration of MG senescence in vitro and neuroinflammation in vivo. To our knowledge, our data provide preliminary evidence indicating that up-regulated succinylation modifications elicit a senescence phenotype in MG through alterations in energy metabolism. Moreover, these findings suggest that manipulation of succinylation levels may offer valuable insights into the treatment of aging-related neuroinflammation., Competing Interests: Declarations Ethical approval All procedures were in accordance with the Dalian Medical University guidelines for the proper care and use of laboratory animals and were approved by the Laboratory Animal Care and Use Committee of Dalian Medical University. Consent for publication Not applicable. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

20-Hydroxyeicosatetraenoic acid (20-HETE) is associated with secondary damage in traumatic brain injury (TBI) of the immature brain. Microglial activation is pivotal in this process. However, the underlying mechanism of action remains unknown. While 20-HETE interacts with G protein-coupled receptor 75 (GPR75) in some pathological processes, their interaction in brain tissue remains uncertain. This study aimed to investigate whether 20-HETE can activate microglia by binding to GPR75 in TBI of the immature brain. Drug affinity responsive molecular target stability (DARTS) assays, cycloheximide (CHX) chase assays, and auto-dock assays were employed to analyze the interaction between 20-HETE and GPR75. The expression levels of cytochrome P450 4A (CYP4A) and GPR75 in activated microglia in an immature brain TBI model were observed by western blot and multiple immunofluorescence staining. The effects of different levels of 20-HETE expression and lentivirus-mediated GPR75 gene silencing on 20-HETE-induced inflammatory factor release from BV-2 cells were observed by enzyme-linked immunoassay (ELISA). The phosphorylation levels of the downstream Src kinase, epidermal growth factor receptor (EGFR), and nuclear factor (NF)-κB were assessed using western blot. Cell viability and apoptosis were detected by CCK-8 and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assays. 20-HETE bound to the GPR75 protein and inhibited its degradation. GPR75 gene silencing reversed the 20-HETE-induced inflammatory activation of BV-2 cells, effectively inhibiting the activation of the Src/EGFR/NF-κB pathway and the effects of 20-HETE on cell viability and the apoptosis rate. In contrast, overexpression of GPR75 had the opposite effect. In addition, after immature brain TBI, the 20-HETE and GPR75 expression levels were upregulated in microglia, with significant activation of the Src/EGFR/NF-κB pathway. Inhibition of 20-HETE synthesis with N-hydroxy-N'-(4-n-butyl-2-methylphenyl) formamidine (HET0016) produced the opposite effect. 20-HETE regulates the Src/EGFR/NF-κB signaling pathway via GPR75 to activate microglia, promoting immature brain TBI. These findings offer a novel target for promoting the brain injury effect of 20-HETE., Competing Interests: Declarations Ethical Approval All animal works were approved by the Animal Care and Use Committee of Chongqing Medical University and were performed following the guidelines of the National Institutes of Health (No. IACUC-CQMU-2023-0155). Competing Interests The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Translocator protein (TSPO) is a mitochondrial protein expressed by microglia, ligands for which are used as a marker of neuroinflammation in PET studies of Alzheimer's disease (AD). We previously showed increasing TSPO load in the cerebral cortex with AD progression, consistent with TSPO PET scan findings. Here, we aim to characterise the microglial phenotype associated with TSPO expression to aid interpretation of the signal generated by TSPO ligands in patients. Human post-mortem sections of temporal lobe (TL) and cerebellum (Cb) from cases classified by Braak group (0-II, III-IV, V-VI; each n = 10) were fluorescently double labelled for TSPO and microglial markers: Iba1, HLA-DR, CD68, MSR-A and CD64. Quantification was performed on scanned images using QuPath software to assess the microglial phenotype of TSPO. Qualitative analysis was also performed for TSPO with GFAP (astrocytes), CD31 (endothelial cells) and CD163 (perivascular macrophages) to characterise the cellular profile of TSPO. The percentage of CD68 + TSPO + double-labelled cells was significantly higher than for other microglial markers in both brain regions and in all Braak stages, followed by MSR-A + TSPO + microglia. Iba1 + TSPO + cells were more numerous in the cerebellum than the temporal lobe, while CD64 + TSPO + cells were more numerous in the temporal lobe. No differences were observed for the other microglial markers. TSPO expression was also detected in endothelial cells, but not detected in astrocytes nor in perivascular macrophages. Our data suggest that TSPO is mainly related to a phagocytic profile of microglia (CD68 + ) in human AD, potentially highlighting the ongoing neurodegeneration., Competing Interests: Declarations Conflict of interests The authors report no competing interests. Ethical approval The study was carried out in accordance with relevant guidelines and regulations under the South–West Dementia Brain Bank ethical approval (NRES Committee South–West Central Bristol, REC reference: 08/H0106/28 + 5)., (© 2024. The Author(s).)

Background: Diabetes-associated cognitive dysfunction, characterized by hippocampal synaptic loss as an early pathological feature, seriously threatens patients' quality of life. Synapses are dynamic structures, and hormones play important roles in modulating the formation and elimination of synapses. The pituitary, the master gland of the body, releases several hormones with multiple roles in hippocampal synaptic regulation. In this study, we aimed to explore the relationship between pituitary hormones and cognitive decline in diabetes., Methods: A total of 744 patients with type 2 diabetes (T2DM) (445 men and 299 postmenopausal women) who underwent serum pituitary hormone level assessments, comprehensive cognitive evaluations and MRI scans were enrolled. Dynamic diet interventions were applied in both chow diet-fed mice and high-fat diet (HFD)-fed diabetic mice. The cognitive performance and hippocampal pathology of prolactin (PRL)-knockout mice, neuronal prolactin receptor (PRLR)-specific knockout mice and microglial PRLR-specific knockout mice were assessed. Microglial PRLR-specific knockout mice were fed an HFD to model diabetes. Diabetic mice received an intracerebroventricular infusion of recombinant PRL protein or vehicle., Results: This clinical study revealed that decreased PRL levels were associated with cognitive impairment and hippocampal damage in T2DM patients. In diabetic mice, PRL levels diminished before hippocampal synaptic loss and cognitive decline occurred. PRL loss could directly cause cognitive dysfunction and decreased hippocampal synaptic density. Knockout of PRLR in microglia, rather than neurons, induced hippocampal synaptic loss and cognitive impairment. Furthermore, blockade of PRL/PRLR signaling in microglia exacerbated abnormal microglial phagocytosis of synapses, further aggravating hippocampal synaptic loss and cognitive impairment in diabetic mice. Moreover, PRL infusion reduced microglia-mediated synaptic loss, thereby alleviating cognitive impairment in diabetic mice., Conclusion: PRL is associated with cognitive dysfunction and hippocampal damage in T2DM patients. In diabetes, a decrease in PRL level drives hippocampal synaptic loss and cognitive impairment by increasing microglia-mediated synapse engulfment. Restoration of PRL levels ameliorates cognitive dysfunction and hippocampal synaptic loss in diabetic mice., Competing Interests: Declaration Ethics approval and consent to participate The study protocols of participants was approved by the ethics committee of Nanjing Drum Tower Hospital by the Ethics Review Committee of Nanjing Drum Tower Hospital Affiliated to Nanjing University Medical School (Approval number: 2017-017-01). All animal experimental procedures were conducted under the Institutional Animal Care and Use Committee-approved protocols (2005010) at Nanjing University according to Laboratory Animal Care Guidelines. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Several cardiovascular traits and diseases co-occur with Alzheimer's disease. We mapped their shared genetic architecture using multi-trait genome-wide association studies. Subsequent fine-mapping and colocalisation highlighted 16 genetic loci associated with both Alzheimer's and cardiovascular diseases. We prioritised rs11786896, which colocalised with Alzheimer's disease, atrial fibrillation and expression of PLEC in the heart left ventricle, and rs7529220, which colocalised with Alzheimer's disease, atrial fibrillation and expression of C1Q family genes. Single-cell RNA-sequencing data, co-expression network and protein-protein interaction analyses provided evidence for different mechanisms of PLEC, which is upregulated in left ventricular endothelium and cardiomyocytes with heart failure and in brain astrocytes with Alzheimer's disease. Similar common mechanisms are implicated for C1Q in heart macrophages with heart failure and in brain microglia with Alzheimer's disease. These findings highlight inflammatory and pleomorphic risk determinants for the co-occurrence of Alzheimer's and cardiovascular diseases and suggest PLEC, C1Q and their interacting proteins as potential therapeutic targets., Competing Interests: Competing interests The authors declare no comparing interests., (© 2024. The Author(s).)

Autophagy has both protective and pathogenetic effects on injury caused by cerebral ischemia/reperfusion (I/R). Our previous research has indicated that stimulator of interferon genes (STING) could orchestrate microglia polarization following middle cerebral artery occlusion. However, it remains largely unexplored whether STING balances microglial polarization by regulating autophagy in brain I/R injury. Here, STING was observed to show an up-regulation in the microglia from mice subjected to experimental ischemic stroke. Strikingly, the deletion of STING led to the significant skewness of microglia activated by ischemia from a pro- to anti-inflammatory state and substantially alleviated ischemia-induced infarction and neuronal injury. In addition, STING-null mice can restore long-term neurobehavioral function. Then, the crosstalk between neuroinflammation and microglia autophagy was analyzed. The differential activity of autophagy in wild-type and STING-knockout (KO) mice or primary microglia was largely reversed when STING was restored in microglia. Irritating autophagy by rapamycin skewed the anti‑inflammatory state induced by STING-KO to a pro‑inflammatory state in microglia. Furthermore, microtubule-associated protein light-chain-3 (LC3) was identified as the key factor in the STING regulation of autophagy by glutathione-S-transferase (GST) pull-down analysis. Mechanically, STING can directly interact with LC3 through the STING transmembrane domain (1-139aa). Herein, current data determine the pivotal role of autophagy, specifically via LC3 protein, in the regulation of microglial phenotypic transformation by STING. These findings may provide a possible treatment target for delaying the progression of ischemic stroke., Competing Interests: Competing interests The authors declare no competing interests. Ethics approval The animal study was reviewed and approved by The First Affiliated Hospital of the University of Science and Technology of China., (© 2024. The Author(s).)

Glia is pivotal in regulating neuronal stem cell proliferation, functioning, and nervous system homeostasis, significantly influencing neuronal health and disorders. Dysfunction in glial activity is a key factor in the development and progression of brain pathology. However, a deeper understanding of the intricate nature of glial cells and their diverse role in neurological disorders is still required. To this end, we conducted data mining to retrieve literature from PubMed and Google Scholar using the keywords: glia, Drosophila, neurodegeneration, and mammals. The retrieved literature was manually screened and used to comprehensively understand and present the different glial types in Drosophila, i.e., perineurial, subperineurial, cortex, astrocyte-like and ensheathing glia, their relevance with mammalian counterparts, mainly microglia and astrocytes, and their potential to reveal complex neuron-glial molecular networks in managing neurodegenerative processes., Competing Interests: Declarations Competing interests The authors declare no competing interests. Ethical approval Not applicable., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Microgliosis plays a critical role in diet-induced hypothalamic inflammation. A few hours after a high-fat diet (HFD), hypothalamic microglia shift to an inflammatory phenotype, and prolonged fat consumption leads to the recruitment of bone marrow-derived cells to the hypothalamus. However, the transcriptional signatures and functions of these cells remain unclear. Using dual-reporter mice, this study reveals that CX3CR1-positive microglia exhibit minimal changes in response to a HFD, while significant transcriptional differences emerge between microglia and CCR2-positive recruited myeloid cells, particularly affecting chemotaxis. These recruited cells also show sex-specific transcriptional differences impacting neurodegeneration and thermogenesis. The chemokine receptor CXCR3 is emphasized for its role in chemotaxis, displaying notable differences between recruited cells and resident microglia, requiring further investigation. Central immunoneutralization of CXCL10, a ligand for CXCR3, resulted in increased body mass and decreased energy expenditure, especially in females. Systemic chemical inhibition of CXCR3 led to significant metabolic changes, including increased body mass, reduced energy expenditure, elevated blood leptin, glucose intolerance, and decreased insulin levels. This study elucidates the transcriptional differences between hypothalamic microglia and CCR2-positive recruited myeloid cells in diet-induced inflammation and identifies CXCR3-expressing recruited immune cells as protective in metabolic outcomes linked to HFD consumption, establishing a new concept in obesity-related hypothalamic inflammation., Competing Interests: NM, AZ, CA, GR, DS, JC, NC, PM, EA, LV No competing interests declared, (© 2024, Mendes et al.)

Background: Retinitis pigmentosa is a neurodegenerative disease with major pathologies of photoreceptor apoptosis and immune imbalance. Mesenchymal stem cells (MSCs) have been approved for clinical application for treating various immune-related or neurodegenerative diseases. The objective of this research was to investigate the mechanisms underlying the safeguarding effects of MSC-derived exosomes in a retinal degenerative disease model., Methods: Interferon gamma-stimulated exosomes (IFNγ-Exos) secreted from MSCs were isolated, purified, and injected into the vitreous body of RCS rats on postnatal day (P) 21. Morphological and functional changes in the retina were examined at P28, P35, P42, and P49 in Royal College of Surgeons (RCS) rats. The mechanism was explored using high-throughput sequencing technology and confirmed in vitro., Results: Treatment with IFNγ-Exo produced better protective effects on photoreceptors and improved visual function in RCS rats. IFNγ-Exo significantly suppressed the activated microglia and inhibited the inflammatory responses in the retina of RCS rats, which was also confirmed in the lipopolysaccharide-activated microglia cell line BV2. Furthermore, through tRNA-derived small RNA (tsRNA) sequencing, we found that IFNγ-Exos from MSCs contained higher levels of Other-1_17-tRNA-Phe-GAA-1-M3, Other-6_23-tRNA-Lys-TTT-3, and TRF-57:75-GLN-CGG-2-m2 than native exosomes, which mainly regulated inflammatory and immune-related pathways, including the mTOR signaling pathway and EGFR tyrosine kinase inhibitor resistance., Conclusions: IFNγ stimulation enhanced the neuroprotective effects of MSC-derived exosomes on photoreceptors of the degenerative retina, which may be mediated by immune regulatory tsRNAs acting on microglia. In conclusion, IFNγ-Exo is a promising nanotherapeutic agent for the treatment of retinitis pigmentosa., Competing Interests: Declarations Ethics approval and consent to participate The authors declare that they have consented to the scientific content and authorship of this study. This study was approved by the Institutional Animal Care and Use Committee of Army Medical University, Chongqing, China. All animal trials were approved by the Army Medical University Institutional Review Board, and all trials met guidelines. The production certificate number for our laboratory animal is SCXK-PLA-20120011, and the occupancy permit number is SYXK-PLA-20120031. All procedures in this study were approved. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Oligodendrocytes are critical for CNS myelin formation and are involved in preterm-birth brain injury (PBI) and multiple sclerosis (MS), both of which lack effective treatments. We present a pharmacogenomic approach that identifies compounds with potent pro-oligodendrogenic activity, selected through a scoring strategy (OligoScore) based on their modulation of oligodendrogenic and (re)myelination-related transcriptional programs. Through in vitro neural and oligodendrocyte progenitor cell (OPC) cultures, ex vivo cerebellar explants, and in vivo mouse models of PBI and MS, we identify FDA-approved leucovorin and dyclonine as promising candidates. In a neonatal chronic hypoxia mouse model mimicking PBI, both compounds promote neural progenitor cell proliferation and oligodendroglial fate acquisition, with leucovorin further enhancing differentiation. In an adult MS model of focal de/remyelination, they improve lesion repair by promoting OPC differentiation while preserving the OPC pool. Additionally, they shift microglia from a pro-inflammatory to a pro-regenerative profile and enhance myelin debris clearance. These findings support the repurposing of leucovorin and dyclonine for clinical trials targeting myelin disorders, offering potential therapeutic avenues for PBI and MS., Competing Interests: Competing interests Jean-Baptiste Hure, Carlos Parras, Olivier Raineateau, and Louis Foucault are inventors in the patent entitled ‘Organic molecules for 1312 treating myelin pathologies’, published on September 28th, 2023 (WO2023180474) that is based on most of the data published in this study. Patent applicants: ICM - Paris Brain Institute, INSERM, CNRS, AAPHP, Sorbonne Université, Université Claude Bernard Lyon 1. The other authors declare no competing interests., (© 2024. The Author(s).)

The introduction of antiretroviral therapy has markedly improved the management of HIV-associated neurocognitive disorders (HAND). However, HAND still affects nearly half of HIV-infected individuals, presenting significant challenges to their well-being. This highlights the critical need for a deeper understanding of HAND mechanisms. Among HIV viral proteins, Nef is notable for its multifaceted role in HIV pathogenesis, though its specific involvement in HAND remains unclear. To investigate this, we used a murine model infected with Nef-expressing (EcoHIV) and Nef-deficient (EcoHIVΔNef) murine HIV. Comparative analyses revealed increased neuroinflammation and reduced myelin and neuronal integrity in EcoHIV-infected brains compared with those with EcoHIVΔNef. Both viruses induced astrogliosis, with stronger GFAP activation in Nef-deficient infections. These findings suggest that Nef contributes to neuroinflammation, primarily through microglial targeting and demyelination, although other factors may regulate astrogliosis. Our results indicate that Nef may significantly contribute to neuronal injury in EcoHIV-infected mice, offering insights into Nef-induced neuropathology in HAND and guiding future research., (© 2024 Schenck et al.)

Spatially heterogeneous synapse loss is a characteristic of many psychiatric and neurological disorders, but the underlying mechanisms are unclear. Here, we show that spatially-restricted complement activation mediates stress-induced heterogeneous microglia activation and synapse loss localized to the upper layers of the medial prefrontal cortex (mPFC) in male mice. Single cell RNA sequencing also reveals a stress-associated microglia state marked by high expression of the apolipoprotein E gene (Apoe high ) localized to the upper layers of the mPFC. Mice lacking complement component C3 are protected from stress-induced layer-specific synapse loss, and the Apoe high microglia population is markedly reduced in the mPFC of these mice. Furthermore, C3 knockout mice are also resilient to stress-induced anhedonia and working memory behavioral deficits. Our findings suggest that region-specific complement and microglia activation can contribute to the disease-specific spatially restricted patterns of synapse loss and clinical symptoms found in many brain diseases., Competing Interests: Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

The role of nonneuronal cells in the resolution of cerebral ischemia remains to be fully understood. To decode key molecular and cellular processes that occur after ischemia, we performed spatial and single-cell transcriptomic profiling of the male mouse brain during the first week of injury. Cortical gene expression was severely disrupted, defined by inflammation and cell death in the lesion core, and glial scar formation orchestrated by multiple cell types on the periphery. The glial scar was identified as a zone with intense cell-cell communication, with prominent ApoE-Trem2 signaling pathway modulating microglial activation. For each of the three major glial populations, an inflammatory-responsive state, resembling the reactive states observed in neurodegenerative contexts, was observed. The recovered spectrum of ischemia-induced oligodendrocyte states supports the emerging hypothesis that oligodendrocytes actively respond to and modulate the neuroinflammatory stimulus. The findings are further supported by analysis of other spatial transcriptomic datasets from different mouse models of ischemic brain injury. Collectively, we present a landmark transcriptomic dataset accompanied by interactive visualization that provides a comprehensive view of spatiotemporal organization of processes in the postischemic mouse brain., Competing Interests: Competing interests statement:The authors declare no competing interest.

The seeded growth of pathogenic protein aggregates underlies the pathogenesis of Alzheimer's disease (AD), but how this pathological cascade is initiated is not fully understood. Sporadic AD is linked genetically to apolipoprotein E (APOE) and other genes expressed in microglia related to immune, lipid, and endocytic functions. We generated a transgenic knockin mouse expressing HaloTag-tagged APOE and optimized experimental protocols for the biochemical purification of APOE, which enabled us to identify fibrillary aggregates of APOE in mice with amyloid-β (Aβ) amyloidosis and in human AD brain autopsies. These APOE aggregates that stained positive for β sheet-binding dyes triggered Aβ amyloidosis within the endo-lysosomal system of microglia, in a process influenced by microglial lipid metabolism and the JAK/STAT signaling pathway. Taking these observations together, we propose a model for the onset of Aβ amyloidosis in AD, suggesting that the endocytic uptake and aggregation of APOE by microglia can initiate Aβ plaque formation., Competing Interests: Declaration of interests C.H. has collaboration contract with Denali for the development of TREM2 agonists., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Pediatric high-grade gliomas (pHGGs), including hemispheric pHGGs and diffuse midline gliomas (DMGs), harbor mutually exclusive tumor location-specific histone mutations. Using immunocompetent de novo mouse models of pHGGs, we demonstrated that myeloid cells were the predominant infiltrating non-neoplastic cell population. Single-cell RNA sequencing (scRNA-seq), flow cytometry, and immunohistochemistry illustrated the presence of heterogeneous myeloid cell populations shaped by histone mutations and tumor location. Disease-associated myeloid (DAM) cell phenotypes demonstrating immune permissive characteristics were identified in murine and human pHGG samples. H3.3K27M DMGs, the most aggressive DMG, demonstrated enrichment of DAMs. Genetic ablation of chemokines Ccl8 and Ccl12 resulted in a reduction of DAMs and an increase in lymphocyte infiltration, leading to increased survival of tumor-bearing mice. Pharmacologic inhibition of chemokine receptors CCR1 and CCR5 resulted in extended survival and decreased myeloid cell infiltration. This work establishes the tumor-promoting role of myeloid cells in DMG and the potential therapeutic opportunities for targeting them., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Parkinson's disease (PD) is the second most common neurodegenerative disorder whose etiology remains unknown. The immune system has been implicated in hallmarks of PD including aggregation of α-synuclein and death of dopaminergic neurons in the substantia nigra. As a core regulator of immune response and inflammation, liver X receptors (LXRs) have been shown to have protective effects in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD. With two isoforms of LXRs (LXRα and LXRβ) expressed in the brain, their roles and distributions in this tissue remain largely unexplored. Here, we used MPTP to mimic symptoms and biomedical changes seen in PD in LXRα -/- and wild-type mice to investigate the role of LXRα in the etiology and progression of PD. We found that MPTP is unable to induce motor deficits, anxiety-like behavior in LXRα -/- mice, which has been seen in WT mice. Gene ontology analysis of RNA sequencing revealed that knockout of LXRα led to enrichment of the process, including immune response and inflammation in the midbrain. In addition, MPTP did not lead to dopaminergic neuron death in the striatum and substantia nigra in LXRα -/- mice, the basal GFAP protein level, and pro-inflammatory cytokines were elevated in LXRα -/- mice. Lastly, the microglia activation and astrogliosis caused by MPTP intoxication we found in WT mice were abolished in LXRα -/- mice. To sum up, we conclude that LXRα is a critical regulator in MPTP intoxication and may play a unique role in astrogliosis seen in the neuroinflammation of PD., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 International Brain Research Organization (IBRO). Published by Elsevier Inc. All rights reserved.)

Stress, a risk factor for major depressive disorder and Alzheimer disease, leads to the release of high-mobility group box-1 (HMGB1) protein, which in turn causes neuroinflammation. The mechanism underlying stress-induced HMGB1 release is unknown, but stress-associated glucocorticoids could be involved. Primary cultured rat cortical microglia and neurons were treated with corticosterone, a stress-associated glucocorticoid, and HMGB1 release was measured by ELISA and western blotting to test this hypothesis. With corticosterone treatment, significant HMGB1 was released in microglia but not in neuronal cell cultures. HMGB1 mRNA expression and HMGB1 protein expression in microglia were not affected by corticosterone treatment. Thus, the source of extracellular HMGB1 released into the medium is likely to be existing nuclear HMGB1 rather than newly synthesized HMGB1. Corticosterone-induced HMGB1 release in microglia culture was significantly attenuated by blocking glucocorticoid receptors but not mineralocorticoid receptors. Dexamethasone, a selective glucocorticoid receptor agonist, and dexamethasone-bovine serum albumin (BSA), a membrane-impermeable glucocorticoid receptor agonist used to confirm the membrane receptor-mediated effects of glucocorticoids, increased the release of HMGB1. Immunocytochemistry showed that HMGB1 translocated from the nucleus to the cytoplasm following dexamethasone or dexamethasone-BSA treatment through glucocorticoid receptors. The present findings suggest that glucocorticoids stimulate microglial membrane glucocorticoid receptors and trigger cytoplasmic translocation and extracellular release of nuclear HMGB1. Thus, under stress conditions, glucocorticoids induce microglial HMGB1 release, leading to a neuroinflammatory state that could mediate neurological disorders., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Takahisa Shimoda is working in Laboratory for Pharmacology, Pharmaceuticals Research Center, Asahi Kasei Pharma Co. Ltd.. This study was conducted fully independent of the project in the Asahi Kasei Pharma Co., Ltd. The other authors declare no conflict of interest., (Copyright © 2024 International Brain Research Organization (IBRO). Published by Elsevier Inc. All rights reserved.)

Previous studies have demonstrated the roles of both microglia homeostasis and RNA editing in sepsis-associated encephalopathy (SAE), yet their relationship remains to be elucidated. In this study, we analyzed bulk and single-cell RNA-seq (scRNA) datasets containing 107 brain tissue and microglia samples from mice with microglial depletion and repopulation to explore canonical RNA editing associated with microglia homeostasis and evaluate its role in SAE. Analysis of mouse brain RNA-Seq revealed hallmarks of microglial repopulation, including peak expressions of Apobec1 and Apobec3 at Day 5 of repopulation and dramatically altered B2m RNA editing. Significant time-dependent changes in brain RNA editing during microglial depletion and repopulation were primarily observed in synapse-related genes, such as Tbc1d24 and Slc1a2. ScRNA-Seq revealed heterogeneous RNA editing among microglia subpopulations and their distinct changes associated with microglia homeostasis. Moreover, repopulated microglia from lipopolysaccharide (LPS)-induced sepsis mice exhibited intensified up-regulation of Apobec1 and Apobec3, with distinct RNA editing responses to LPS, mainly involved in immune-related pathways. The hippocampus from sepsis mice induced by peritoneal contamination and infection showed upregulated Apobec1 and Apobec3 expression, and altered RNA editing in immune-related genes, such as B2m and Mier1, and nervous-related lncRNA Meg3 and Snhg11, both of which were repressed by microglial depletion. Furthermore, the expression of complement-related genes, such as C4b and Cd47, was substantially correlated with RNA editing activity in microglia homeostasis and SAE. Our study demonstrates canonical RNA editing associated with microglia homeostasis and provides new insights into its potential role in SAE., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 International Brain Research Organization (IBRO). Published by Elsevier Inc. All rights reserved.)

Aim: Explore the effects of mitochondrial transplantation (MT) after cardiopulmonary resuscitation (CPR) on the polarization of microglia/macrophages (MG/MΦ) and neurological function., Methods: Seventy-five Sprague-Dawley rats were randomly divided into five groups: sham, normal saline (NS), vehicle, mitochondria (Mito), and non-functional mitochondria (N-Mito) group. Rats in sham group underwent surgical procedures without cardiac arrest, while the other four groups underwent cardiac arrest and CPR, and then received NS, respiration buffer, mitochondrial suspension or non-functional mitochondria, immediately after the restoration of spontaneous circulation (ROSC). The number of mitochondria in the hippocampus, the morphology and structure of mitochondria in MG/MΦ, the phenotype of MG/MΦ, and hippocampal tissue injury, neuroinflammation, and neuronal apoptosis were detected on days 1 and 3 after ROSC. Neurodeficit score (NDS) was performed on days 1, 3, 7, 15 and 30 after ROSC., Results: Compared with other groups, the number of mitochondria in the hippocampus was increased, and the morphology and structure of mitochondria in MG/MΦ were significantly improved in the Mito group. Our results show higher expression of M2-type markers in MG/MΦ and decreased hippocampal tissue damage in the Mito group. Levels of NSE and S100β in serum, and TNF-α, IL-6 in the hippocampus were decreased, while the levels of TGF-β and IL-10 were increased in the Mito group. Apoptosis rate of neurons in the Mito group was decreased and the NDS of the Mito group was higher than the other groups., Conclusions: Exogenous MT can improve neurological function after CPR by promoting the polarization of MG/MΦ to M2-type cells, and this could be a potential method for brain protection after CPR., Competing Interests: Declarations Ethics approval and consent to participate Not applicable. Consent for publication All listed authors consent to the submission, and all data are used with the consent of the person generating the data. Competing interests The authors declare that they have no competing interests., (© 2024. The Author(s).)

Sleepiness is commonly associated with neuroinflammation; however, the underlying neuroregulatory mechanisms remain unclear. Previous research suggests that the paraventricular thalamus (PVT) plays a crucial role in regulating sleep-wake dynamics; thus, neurological abnormalities in the PVT may contribute to neuroinflammation-induced sleepiness. To test this hypothesis, we performed electroencephalography recordings in mice treated with lipopolysaccharide (LPS) and found that the mice exhibited temporary sleepiness lasting for 7 days. Using the Fos-TRAP method, fiber photometry recordings, and immunofluorescence staining, we detected temporary PVT neuron hypoactivation and microglia activation from day 1 to day 7 post-LPS treatment. Combining the results of bulk and single-cell RNA sequencing, we found upregulation of aconitate decarboxylase 1 (Acod1) in PVT microglia post-LPS treatment. To investigate the role of Acod1, we manipulated Acod1 gene expression in PVT microglia via stereotactic injection of short hairpin RNA adenovirus. Knockdown of Acod1 exacerbated inflammation, neuronal hypoactivation, and sleepiness. Itaconate is a metabolite synthesized by the enzyme encoded by Acod1. Finally, we confirmed that exogenous administration of an itaconate derivative, 4-octyl itaconate, could inhibit microglia activation, alleviate neuronal dysfunction, and relieve sleepiness. Our findings highlight PVT's role in inflammation-induced sleepiness and suggest Acod1 as a potential therapeutic target for neuroinflammation., Competing Interests: Competing interests The authors declare no competing interest., (© 2024. The Author(s).)

A significant challenge for chimeric antigen receptor (CAR) T cell therapy against glioblastoma (GBM) is its immunosuppressive microenvironment, which is densely populated by protumoral glioma-associated microglia and macrophages (GAMs). Myeloid immune checkpoint therapy targeting the CD47-signal regulatory protein alpha (SIRPα) axis induces GAM phagocytic function, but CD47 blockade monotherapy is associated with toxicity and low bioavailability in solid tumors. In this work, we engineer a CAR T cell against epidermal growth factor receptor variant III (EGFRvIII), constitutively secreting a signal regulatory protein gamma-related protein (SGRP) with high affinity to CD47. Anti-EGFRvIII-SGRP CAR T cells eradicate orthotopic EGFRvIII-mosaic GBM in vivo, promoting GAM-mediated tumor cell phagocytosis. In a subcutaneous CD19 + lymphoma mouse model, anti-CD19-SGRP CAR T cell therapy is superior to conventional anti-CD19 CAR T. Thus, combination of CAR and SGRP eliminates bystander tumor cells in a manner that could overcome main mechanisms of CAR T cell therapy resistance, including immune suppression and antigen escape., (© 2024. The Author(s).)

Background: There is growing evidence that atrial fibrillation (AF) is a risk factor for cognitive impairment (CI) and dementia in the presence or absence of stroke. The purpose of this study was to explore the mechanism of CI caused by AF., Methods: Eighteen male canines were randomly divided into a sham group, a pacing group, and a pacing + GW4869 group. An experimental model of AF was established by rapid atrial pacing (450 beats/min) for 2 weeks, and the sham group received pacemaker implantation without atrial pacing. The GW4869 group received an intravenous GW4869 injection (0.3 mg/kg, once a day) during pacing. All canines were locally injected with Ad-CD63-RFP in epicardial adipose tissue (EAT) to trace the exosomes. Ultracentrifugation was employed to isolate EAT-derived exosomes, followed by RNA sequencing and quantitative real-time PCR (qRT-PCR) to assess RNA in both exosomes and hippocampal tissue. The miRanda database was used to predict the targeting relationships between miRNA and mRNA, which were further validated by luciferase reporter assays. Western blot analysis was conducted to detect exosomal markers (CD63, CD81, TSG101) in EAT exosomes, while immunofluorescence was used to detect Ad-CD63-RFP signals in both EAT and hippocampal tissues, as well as microglial activation marker IBA-1. To further explore the effects of exosomes on microglial cells, in vitro experiments using brain microvascular endothelial cells (bEnd3) and microglial cells (BV2) were conducted. IBA-1 expression and RNA levels in BV2 cells were analyzed by immunofluorescence and qRT-PCR, respectively., Results: After 14 days of pacing of the canine atrium, compared to the sham group, both the pacing and GW4869 groups exhibited an increased number of AF inductions, along with prolonged AF duration. The fluorescence intensity of Ad-CD63-RFP and the microglial activation marker IBA-1 were markedly greater in the hippocampus. RNA sequencing showed that the differentially expressed gene cfa-miR-22e in EAT exosomes was upregulated, and its target gene IL33 was downregulated in the hippocampus. qRT-PCR showed that the levels of cfa-miR-22e were increased in both EAT exosomes and the hippocampus, while the expression of IL-33, a target of cfa-miR-22e, was decreased in the hippocampus. The administration of GW4869 abolished these effects. The in vitro results from bEnd3 and BV2 cell experiments were consistent with the conclusions drawn from the in vivo studies., Conclusion: Our study indicated that the exosomes secreted by EAT in canines with AF can penetrate the BBB and activate microglia in the hippocampus through the cfa-miR-22e/IL33 signalling pathway., (© 2024. The Author(s).)

Glioma associated macrophages/microglia (GAMs) play an important role in glioblastoma (GBM) progression, due to their massive recruitment to the tumor site and polarization to a tumor promoting phenotype. GAMs secrete a variety of cytokines, which facilitate tumor cell growth and invasion, and prevent other immune cells from mounting an immune response against the tumor. Here, we demonstrate that zinc finger and BTB containing domain 18 (ZBTB18), a transcriptional repressor with tumor suppressive function in glioblastoma, impairs the production of key cytokines, which function as chemoattractant for GAMs. Consistently, we observe a reduced migration of GAMs when ZBTB18 is expressed by glioblastoma cells, both in cell culture and in vivo experiments. Moreover, RNA sequencing analysis shows that the presence of ZBTB18 in glioblastoma cells alters the commitment of conditioned microglia, suggesting the loss of the immune-suppressive phenotype and the acquisition of pro-inflammatory features. Thus, therapeutic approaches to increase ZBTB18 expression in GBM cells could represent an effective adjuvant to immune therapy in GBM., (© 2024. The Author(s).)