TREM2 activation alleviates neural damage via Akt/CREB/BDNF signalling after traumatic brain injury in mice

Molecularly imprinted nanoparticles hitchhiking on neutrophils for precise treatment of ischemic stroke

Ischemic stroke (IS), the most prevalent type of stroke worldwide, is associated with a variety of complex processes, including oxidative stress, apoptosis, and ferroptosis. Recent findings indicate that inhibiting iron overload as a key regulatory mechanism of ferroptosis profoundly influences the pathogenesis and treatment of IS. In addition, enhanced blood-brain barrier (BBB) penetration and precise targeting of the ischaemic site contribute to improved therapeutic outcomes in IS. In this study, we developed FeSO4 templated-molecularly imprinted nanoparticles (MINPs) with high-affinity recognition of ferrous ions (Fe2+). MINPs exhibited physicochemical properties that perfectly match the polarity and condensed structure of Fe2+, resulting in the effective and specific clearance of Fe2+ through efficient and selective adsorption both in vivo and in vitro. Moreover, MINPs hitchhiked circulating neutrophils, thereby facilitating their penetration through BBB and enhancing targeted delivery to the ischemic brain. Our results, supported by transcriptomic analysis, further elucidated the molecular mechanisms by which MINPs significantly inhibit ferroptosis while concurrently regulating apoptosis and inflammation, thereby conferring marked neuroprotection against IS.

TREM2 activation reduces white matter injury via PI3K/Akt/GSK-3β signalling after intracerebral haemorrhage

BACKGROUND

White matter injury (WMI) considerably exacerbates the prognosis following intracerebral haemorrhage (ICH). While the triggering receptor on myeloid cells 2 (TREM2) is recognized for its neuroprotective roles in a range of neurological disorders through the modulation of neuroinflammation, phagocytosis, promoting cell survival, its specific function in WMI after ICH has yet to be fully elucidated.

METHODS

This study involved inducing ICH in mice through autologous blood injection. Neurological functions were tested via behavioural assessments and electrophysiological recordings. WMI was examined using immunofluorescence, Luxol fast blue staining, MRI and transmission electron microscopy. Microglia were isolated and analysed using real-time polymerase chain reaction (PCR). Microglia depletion was achieved with PLX3397, primary cultures of microglia and oligodendrocytes were investigated.

RESULTS

The activation of TREM2 resulted in improved neurological outcomes after ICH, correlated with reduced WMI, demonstrated by decreased white matter loss in the corpus striatum, reduced damage to the nodes of Ranvier, and better preservation of myelin and white matter tract integrity. These neuroprotective effects were attributed to changes in microglial states mediated via the PI3K/Akt/GSK-3β signalling pathway. However, the neuroprotective advantages conferred by TREM2 activation were negated in TREM2 KO mice, either through microglia depletion or inhibition of PI3K.

CONCLUSIONS

This research is the first to illustrate that TREM2 activation mitigates WMI following ICH through a microglia-dependent mechanism involving the PI3K/Akt/GSK-3β pathway. TREM2 represents a potential therapeutic target for ICH.

Hydrogen combined with needle-embedding therapy alleviates traumatic brain injury by inhibiting NLRP3 inflammasome activation via STING signaling pathway

BACKGROUND

Traumatic brain injury (TBI) is a primary cause of disability and death worldwide and with unmet effective therapies. Molecular hydrogen (H2) exerts latent therapeutic means for TBI. Nevertheless, few studies have illustrated the roles of hydrogen combined with needle-embedding therapy (H2 + NET) in TBI and its exact mechanism remains unclear. Here, we elucidated the underlying mechanisms of H2 + NET in the TBI progression.

METHODS

Controlled cortical impact (CCI) method was conducted to construct TBI mouse model. The mNSS test was used for neurological function measurement. Nissl staining for evaluating neuronal injury, TUNEL assay for determining neuronal apoptosis and ELISA assay was applied for adenosine, ATP level and inflammatory cytokines determination. The relative mRNA levels of inflammatory elements were assessed by qRT-PCR analysis. Iba-1, NLRP3 and STING expression were determined through immunofluorescence staining. The expression of NLRP3 inflammasome related proteins and STING signaling pathway associated proteins were evaluated using Western blot.

RESULTS

H2 or NET treatment mitigated brain injury and reduced brain water content in CCI-induced TBI mouse model. CCI induction promoted microglia activation and inflammatory response, thereby activating the NLRP3 inflammasome activity and STING signaling pathway, which was partly reversed by H2 or NET treatment. However, H2 + NET significantly ameliorated brain oedema, and further inhibited inflammatory response, NLRP3 inflammasome activation and STING pathway activation in TBI mice when compared to the H2 or NET alone treatment group.

CONCLUSION

Hydrogen combined with needle-embedding therapy acts as a promising intervention method for TBI through inhibiting NLRP3 inflammasome activation via STING signaling pathway.

Icariin attenuates oxidative stress via SIRT1/PGC-1α pathway in SAH mice

Oxidative stress plays a pivotal role in the pathological response of subarachnoid hemorrhage (SAH). Icariin (ICA), with its potent antioxidant properties, exerts neuroprotective effects in stroke. This study investigated the beneficial effects of ICA on SAH-induced oxidative damage and its possible molecular mechanisms. The results indicated that ICA treatment improved both short-term and long-term neurobehavioral functions in mice with SAH. ICA significantly inhibited SAH-induced reactive oxygen species (ROS) generation and lipid peroxidation. Simultaneously, ICA restored the activity of the endogenous antioxidant enzyme system. Furthermore, ICA mitigated mitochondrial damage, improved mitochondrial morphology, further reduced neuronal apoptosis, and decreased brain edema following SAH. Mechanistically, ICA suppressed oxidative stress after SAH by activating Sirtuin 1 (SIRT1), subsequently upregulating the expression of PGC-1α. The SIRT1 inhibitor EX527 significantly inhibited ICA-induced SIRT1 activation and abolished the antioxidant and neuroprotective effects of ICA. In cellular experiments, ICA also inhibited ROS production and enhanced cell viability. These effects were associated with SIRT1 activation and were reversed by EX527 treatment. In conclusion, this study explored the protective effects of ICA against SAH-induced oxidative damage, suggesting that ICA could be a potential therapeutic agent for SAH.

Research developments in the neurovascular unit and the blood‑brain barrier (Review)

The neurovascular unit (NVU) is composed of neurons, glial cells, brain microvascular endothelial cells (BMECs), pericytes, and the extracellular matrix. The NVU controls the permeability of the blood-brain barrier (BBB) and protects the brain from harmful blood-borne and endogenous and exogenous substances. Among these, neurons transmit signals, astrocytes provide nutrients, microglia regulate inflammation, and BMECs and pericytes strengthen barrier tightness and coverage. These cells, due to their physical structure, anatomical location, or physiological function, maintain the microenvironment required for normal brain function. In this review, the BBB structure and mechanisms are examined to obtain a better understanding of the factors that influence BBB permeability. The findings may aid in safeguarding the BBB and provide potential therapeutic targets for drugs affecting the central nervous system.

Choroidal Neovascularization Is Suppressed With Activation of TREM2 in Mononuclear Phagocytes-Brief Report

BACKGROUND

Mononuclear phagocytes contribute to pathological angiogenesis in age-related macular degeneration, a leading worldwide cause of visual impairment. However, the mechanisms that orchestrate the functions of mononuclear phagocytes remain poorly understood. TREM2 (triggering receptor on myeloid cells 2) has been shown to be crucial for the activation of mononuclear phagocytes in atherosclerosis, fatty liver disease, and Alzheimer disease. The objective of this study was to investigate the role of TREM2 in pathological angiogenesis in age-related macular degeneration.

METHODS

C57BL/6J and Trem2 knockout mice were subjected to laser-induced choroidal neovascularization, a model of choroidal neovascular age-related macular degeneration. Purified bovine sulfatide and agonist anti-TREM2 antibody was used to activate TREM2 signaling. The expression of TREM2 or downstream signals were assessed with immunohistochemistry or real-time quantitative PCR. In vitro murine macrophage RAW264.7 cells were used to investigate the direct impact of sulfatide on inflammatory and phagocytic responses.

RESULTS

We found that pharmacological activation of TREM2 suppressed laser-induced choroidal neovessel formation. The activation of TREM2 in mononuclear phagocytes suppressed TNF (tumor necrosis factor) and subsequently promoted phagocytosis.

CONCLUSIONS

These findings demonstrate that activation of TREM2 in mononuclear phagocytes suppresses the proinflammatory response, promotes phagocytosis, and impedes choroidal neovessel formation. Our study provides insight into the critical role of TREM2 in pathological angiogenesis.

Short-Chain Fatty Acids Alleviate Perioperative Neurocognitive Disorders Through BDNF/PI3K/Akt Pathway in Middle-Aged Rats

Perioperative neurocognitive disorders (PND), characterized by persistent cognitive impairment lasting from days to years, present substantial clinical challenges in elderly surgical populations, profoundly compromising functional independence, quality of life, and long-term prognosis. We aimed to investigate the effects of short-chain fatty acids (SCFAs) treatment on PND via mediating Brain-derived neurotrophic factor (BDNF)/Phosphatidylinositol3-kinase (PI3K)/Protein kinase B (Akt) pathway. Using 16S rDNA sequencing targeting the V3-V4 hypervariable regions, we first demonstrated significant gut microbiota dysbiosis in PND model rats, accompanied by altered SCFAs profiles. Subsequent fecal microbiota transplantation (FMT) experiments established causal relationships between PND-associated microbial alterations and spatial cognitive deficits. Mechanistically, SCFAs supplementation attenuated neuronal damage and restored synaptic plasticity, as evidenced by Nissl staining quantification (reduced chromatolysis), TUNEL assay (decreased apoptosis rate), and immunohistochemical analysis (upregulated NeuN expression). Molecular investigations revealed that SCFAs-mediated cognitive improvement involved BDNF upregulation and subsequent PI3K/Akt pathway activation, ultimately enhancing neuronal survival and synaptic integrity. Notably, PND animals exhibited characteristic neuropathological features including synaptic density reduction (PSD-95 downregulation), neuroinflammation amplification (IL-6 elevation), and apoptosis activation-all significantly reversed by SCFA intervention. Our findings establish a novel gut-brain axis mechanism wherein microbiota-derived SCFAs may exert neuroprotection through BDNF-dependent PI3K/Akt signaling, and offer potential therapeutic strategies for PND management.

4,4'-Dimethoxychalcone Mitigates Neuroinflammation Following Traumatic Brain Injury Through Modulation of the TREM2/PI3K/AKT/NF-κB Signaling Pathway

Research on 4,4'-dimethoxychalcone (DMC) in the context of traumatic brain injury (TBI) is extremely limited, and no effective clinical treatments are available to improve outcomes for individuals with TBI. Our study aims to investigate the underlying mechanisms by which DMC may alleviate neuroinflammation and neuronal damage following TBI. This study seeks to provide a theoretical foundation for the development of future pharmacological therapies for TBI. A moderate TBI model was established using the fluid percussion injury (FPI) method. The recovery of neuromotor function following TBI was evaluated using the modified neurological severity score (mNSS), the Morris water maze test, and analysis of cerebral edema. Gene and protein expression levels were quantified using cell viability assays, quantitative real-time polymerase chain reaction (qRT-PCR), Western blotting, enzyme-linked immunosorbent assay (ELISA), immunohistochemistry, and immunofluorescence. Network pharmacology was employed to predict potential targets of DMC, and gene ontology (GO) analysis along with KEGG pathway enrichment was conducted to predict signaling pathways affected by DMC.DMC treatment significantly improved neuromotor deficits in mice after TBI. In both in vivo and in vitro experiments, DMC suppressed microglial activation and decreased the production and release of inflammatory factors. Additionally, DMC reduced neuronal lesions after TBI. DMC notably decreased the elevated expression of triggering receptor expressed on myeloid cells 2 (TREM2) following TBI. Network pharmacological analysis indicated that DMC's therapeutic effects may be mediated through the PI3K/AKT signaling cascade. These findings indicate that DMC has therapeutic potential for TBI, with significant anti-inflammatory and neuroprotective properties likely mediated by the TREM2/PI3K/AKT/NF-κB signaling cascade.

Phosphatidate phosphatase Lipin1 alters mitochondria-associated endoplasmic reticulum membranes (MAMs) homeostasis: effects which contribute to the development of diabetic encephalopathy

Diabetic encephalopathy (DE) is a common, chronic central nervous system complication of diabetes mellitus, and represents a condition without a clear pathogenesis or effective therapy. Findings from recent studies have indicated that a dyshomeostasis of mitochondria-associated endoplasmic reticulum membranes (MAMs) may be involved in the development of neurodegenerative diseases such as DE. MAMs represent a dynamic contact site between mitochondrial and endoplasmic reticulum (ER) membranes, where phospholipid components are exchanged with each other. Previous work within our laboratory has revealed that Lipin1, a critical enzyme related to phospholipid synthesis, is involved in the pathogenesis of DE. Here, we show that Lipin1 is downregulated within the hippocampus of a DE mouse model, an effect which was accompanied with a decrease in MAMs. Knockdown of Lipin1 in the hippocampus of normal mice resulted in a reduction of MAMs, ER stress, abnormal mitochondrial function, as well as impaired synaptic plasticity and cognitive function. These same phenomena were observed in the DE model, while an upregulation of Lipin1 within the hippocampus of DE mice improved these symptoms. Low levels of Lipin1 in DE mice were also associated with neuroinflammation, while an overexpression of Lipin1 significantly ameliorated the neuroinflammation observed in DE mice. In conclusion, Lipin1 ameliorates pathological changes associated with DE in a mouse model via prevention of dyshomeostasis in MAMs. Such findings suggest that Lipin1 may be serve as a new potential target for the treatment of DE.

Danshen-Chuanxiong-Honghua ameliorates neurological function and inflammation in traumatic brain injury in rats via modulating Ghrelin/GHSR

ETHNOPHARMACOLOGICAL RELEVANCE

Guanxin II, proposed by Chen Keji (National master of traditional Chinese medicine), possesses neuroprotective effect. Interestingly, its simplified prescription Danshen-Chuanxiong-Honghua (DCH) can also clinically ameliorate cerebral impairment and improve spatial cognitive deficits, similar to the function of original formula.

AIM OF THE STUDY

We aimed to elucidate the rationality of DCH's natural existence, qualitatively identify DCH-derived phytochemicals, thereby to validate cerebral protective effect, and expose the potential mechanism of DCH and its main absorbed compound ferulic acid (FA).

MATERIALS AND METHODS

The natural rationality of DCH's existence for treating TBI was verified using data mining. The qualitative analysis of DCH extract-derived phytochemicals was conducted through liquid chromatography with mass spectrometry (LC-MS). Controlled cortical impact (CCI) was chosen to establish TBI model. Neurological behavior tests, blood-brain barrier (BBB) permeability test, brain water content measurement, and proinflammatory factors consisting of IL-6, IL-1β, and TNF-α of plasma, and HPA axis-related hormone levels of DA, NA, 5-HT, ghrelin, and BDNF in hippocampus were analyzed by enzyme-linked immunosorbent assay. Network pharmacology was employed to predict potential targets and pathways of DCH intervening TBI. Growth hormone secretagogue receptor (GHSR) antagonist [D-Lys3]-GHRP-6 (D-Lys3) was injected intraperitoneally in TBI rats after waking up. Molecular docking and pharmacological experiment with D-Lys3 were used to verify the pathway.

RESULTS

Twenty-six phytochemicals were identified based on LC-MS. FA, as the primary contributor of DCH, alleviated disruption of BBB and reduced brain edema, suppressed the secretion of proinflammatory factors, such as IL-6, IL-1β, TNF-α, as well as HPA axis-related hormones such as DA, NA, and 5-HT, and ghrelin, and BDNF by regulating the Ghrelin/GHSR pathway. These results were validated by GHSR receptor antagonist, as well as molecule docking.

CONCLUSIONS

Taken together, DCH, when prescribed for the treatment of TBI, has a certain degree of reasonableness. FA, as the main absorbed component, demonstrated a similar function to DCH in improving the blood-brain barrier, promoting neural recovery, and anti-inflammatory effects in TBI rats, primarily via modulating Ghrelin/GHSR.

Inhibition of GPR17/ID2 Axis Improve Remyelination and Cognitive Recovery after SAH by Mediating OPC Differentiation in Rat Model

Myelin sheath injury contributes to cognitive deficits following subarachnoid hemorrhage (SAH). G protein-coupled receptor 17 (GPR17), a membrane receptor, negatively regulates oligodendrocyte precursor cell (OPC) differentiation in both developmental and pathological contexts. Nonetheless, GPR17's role in modulating OPC differentiation, facilitating remyelination post SAH, and its interaction with downstream molecules remain elusive. In a rat SAH model induced by arterial puncture, OPCs expressing GPR17 proliferated prominently by day 14 post-onset, coinciding with compromised myelin sheath integrity and cognitive deficits. Selective Gpr17 knockdown in oligodendrocytes (OLs) via adeno-associated virus (AAV) administration revealed that reduced GPR17 levels promoted OPC differentiation, restored myelin sheath integrity, and improved cognitive deficits by day 14 post-SAH. Moreover, GPR17 knockdown attenuated the elevated expression of the inhibitor of DNA binding 2 (ID2) post-SAH, suggesting a GPR17-ID2 regulatory axis. Bi-directional modulation of ID2 expression in OLs using AAV unveiled that elevated ID2 counteracted the restorative effects of GPR17 knockdown. This resulted in hindered differentiation, exacerbated myelin sheath impairment, and worsened cognitive deficits. These findings highlight the pivotal roles of GPR17 and ID2 in governing OPC differentiation and axonal remyelination post-SAH. This study positions GPR17 as a potential therapeutic target for SAH intervention. The interplay between GPR17 and ID2 introduces a novel avenue for ameliorating cognitive deficits post-SAH.

TREM2 Activation Relieves TMJOA by Stabilizing the Synovial Barrier via Siglec1

Triggering receptor expressed on myeloid cells 2 (TREM2) is an immune receptor that plays a vital role in innate immune responses. This study aims to investigate the effect of TREM2 on synovial barrier homeostasis and synovitis during temporomandibular joint osteoarthritis (TMJOA). The expression level of TREM2 is decreased in the synovium of both patients with TMJOA and a mouse model of TMJOA, accompanied by synovial barrier breakdown. TREM2 overexpression inhibits the macrophage inflammatory response ex vivo and relieves synovial inflammation, cartilage degeneration, and synovial barrier destruction in monosodium iodoacetate-induced TMJOA mice. RNA-seq analysis reveals that Siglec1 serves as a downstream signal that is downregulated after TREM2 activation. Further in vivo and in vitro experiments demonstrate that rhSiglec1 treatment promotes the synthesis and release of inflammatory cytokines, such as interleukin-6 and RANTES, in macrophages and reverses the alleviation effect of TREM2 activation on TMJOA synovial barrier disorders, synovial inflammation, cartilage degradation, and bone destruction. Overall, this study verifies that TREM2 activation alleviates TMJOA pathology by maintaining synovial barrier homeostasis and inhibiting synovial inflammation. These findings provide new insight into the mechanism of TREM2 in the pathogenesis of TMJOA.

TREM2 Modulates Postoperative Cognitive Function in Aged Mice by Inhibiting the NLRP3/caspase-1 Pathway and Apoptosis via PLCγ2 Activation

Postoperative cognitive dysfunction (POCD) is a prevalent complication in elderly patients, with neuroinflammation identified as a key contributing factor. This study investigates the therapeutic potential of the TREM2-PLCγ2 signaling pathway in mitigating neuroinflammation, neuronal apoptosis and cognitive impairment following surgery. We employed both in vivo and in vitro models to investigate the effects of TREM2 activation and its interaction with PLCγ2. Mice subjected to surgery were pre-treated with the TREM2-activating peptide COG1410, and subsequently evaluated for neuroinflammation, neuronal apoptosis, and cognitive function. In vitro studies using microglial cells were conducted to examine the mechanistic relationship between TREM2 and PLCγ2 phosphorylation via SYK. Knockdown experiments and SYK inhibition were performed to determine the hierarchical interaction between TREM2, PLCγ2, and their downstream influence on the NLRP3 inflammasome. Surgery significantly elevated the activation of the NLRP3 inflammasome, along with increased Cleaved Caspase-1, IL-1β, IL-18, and neuronal apoptosis markers. Pre-treatment with COG1410 effectively reduced these pro-inflammatory and pro-apoptotic markers, while alleviating cognitive impairment. TREM2 activation promoted SYK-dependent phosphorylation of PLCγ2, which inhibited NLRP3 inflammasome activation and reduced neuroinflammation. TREM2 knockdown exacerbated microglial inflammation, while PLCγ2 knockdown suppressed NLRP3 activation. Inhibition of SYK impaired the protective effects of the TREM2-PLCγ2 pathway and delayed cognitive recovery in mice. RNA-sequencing further revealed significant alterations in pathways related to neuroinflammation and apoptosis. TREM2 modulates PLCγ2 activity through SYK phosphorylation, thereby alleviating microglial-driven neuroinflammation and neuronal apoptosis, and improving cognitive impairment following surgery. Targeting the TREM2-PLCγ2 pathway presents a promising strategy for the prevention and treatment of POCD.

CPCGI Alleviates Neural Damage by Modulating Microglial Pyroptosis After Traumatic Brain Injury

BACKGROUND

Traumatic brain injury (TBI) is a major global cause of mortality and long-term disability, with limited therapeutic options. Microglial pyroptosis, a form of programmed cell death associated with inflammation, has been implicated in exacerbating neuroinflammation and secondary injury following TBI. Compound porcine cerebroside ganglioside injection (CPCGI) has shown anti-inflammatory and antioxidant properties, but its effects on pyroptosis remain unexplored. This study investigates the role of CPCGI in TBI and its underlying mechanisms.

METHODS

A controlled cortical impact (CCI) model was utilized to establish TBI in vivo, while lipopolysaccharide (LPS) was used in vitro to induce microglial activation that mimicked TBI conditions. The effects of CPCGI on microglial pyroptosis and inflammatory cytokines were analyzed through immunofluorescence, flow cytometry, western blotting, and quantitative real-time PCR (qRT-PCR). The involvement of the NLRP3 inflammasome in CPCGI's mechanism was examined using NLRP3 overexpression or the NLRP3 agonist BMS-986299. A microglia-neuron interaction model was created, and neuronal injury was assessed with the Cell Counting Kit-8 and Fluoro-Jade C (FJC).

RESULTS

Treatment with CPCGI resulted in significant improvement in the neurobehavioral outcomes, reduced lesion volume, and decreased neuronal loss following TBI. Notably, TBI induced microglial pyroptosis and the release of pro-inflammatory cytokines, while CPCGI inhibited microglial pyroptosis, thereby mitigating the inflammatory response and reducing neuronal damage. Mechanistically, overexpression of NLRP3 in microglial cells reversed the inhibitory effects of CPCGI on microglial pyroptosis, indicating that CPCGI's inhibition of microglial pyroptosis may be mediated by the NLRP3 inflammasome. Furthermore, NLRP3 overexpression or administration of the NLRP3 agonist BMS-986299 negated the neuroprotective effects of CPCGI in vivo and in vitro.

CONCLUSION

These findings suggest that CPCGI provides neuroprotection in TBI by targeting NLRP3 inflammasome-mediated microglial pyroptosis, thereby improving the neuroinflammatory microenvironment and promoting neurological recovery. This underscores its potential as a promising candidate for TBI treatment.

TREM2 Impairs Glycolysis to Interrupt Microglial M1 Polarization and Inflammation via JAK2/STAT3 Axis

Cerebral ischemia/reperfusion injury (IRI) is a primary pathophysiological basis of ischemic stroke, a dreadful cerebrovascular event carrying substantial disability and lethality. Triggering receptor expressed on myeloid cells 2 (TREM2) is a membrane glycoprotein that has been notified as a protective factor for cerebral ischemic stroke. On this basis, the paper is thereby goaled to interpret the probable activity and downstream mechanism of TREM2 against cerebral IRI. Cerebral IRI was simulated in murine microglial BV2 cells under oxygen-glucose deprivation and reperfusion (OGD/R) conditions. Western blotting ascertained the expressions of TREM2 and janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) axis-associated proteins. ELISA and RT-qPCR assayed the secretion of inflammatory cytokines. Immunofluorescence and western blotting estimated macrophage polarization. Glycolysis activation was measured through evaluating lactic acid and extracellular acidification rate (ECAR). RT-qPCR and western blotting examined the expressions of glycolytic genes. TREM2 was abnormally expressed and JAK2/STAT3 axis was aberrantly activated in BV2 cells in response to OGD/R. Elevation of TREM2 repressed the inflammatory reaction and glycolysis, inhibited the JAK2/STAT3 axis, whereas promoted M1-to-M2 polarization in OGD/R-injured BV2 cells. Upregulated TREM2 inactivated the glycolytic pathway to relieve OGD/R-induced inflammatory injury and M1 macrophage polarization. Besides, STAT3 activator, colivelin, aggravated the glycolysis, inflammatory injury and drove M1-like macrophage polarization in TREM2-overexpressing BV2 cells exposed to OGD/R. Collectively, TREM2 might produce anti-inflammatory potential in cerebral IRI, which might dependent on the inactivation of glycolytic pathway via intermediating the JAK2/STAT3 axis.

Investigating the Role of Buzhong Yiqi Decoction on Neurogenic Bladder with Network Pharmacology, Molecular Docking, and In Vitro Assays

Buzhong Yiqi decoction (BZYQD) is a traditional Chinese medicine prescription for treating neurogenic bladder (NB). However, the underlying pharmacological mechanism remains unclear. This study aims to clarify the related molecular mechanism. Molecular structure information and targets of core components of BZYQD were obtained from Traditional Chinese Medicines Systems Pharmacology Platform (TCMSP) and SwissTargetPrediction databases. Genes involved in NB were obtained from Comparative Toxicogenomics Database, DisGeNet, GeneCards, and Online Mendelian Inheritance in Man databases. The hub targets of BZYQD in NB treatment were identified by protein-protein interaction (PPI) network analysis with STRING platform and analyzed by gene ontology analysis and the Kyoto Encyclopedia of Genes and Genomics pathway enrichment analysis. Molecular docking was used to verify the binding affinity between the hub targets and the bioactive components of BZYQD. Subsequently, the neuroprotective and anti-inflammatory effects of main bioactive components of BZYQD were investigated with in vitro assays. A total of 131 candidate compounds and 925 predicted target genes were screened. PPI network analysis suggested that ESR1, EGFR, HSP90AA1, MAPK3, AKT1, and CASP3 were the hub targets. BZYQD treatment was associated with hypoxia inducible factor-1 (HIF-1) signaling pathway. Dehydroglyasperin C (DGC), N-cis-feruloyltyramine, shinpterocarpin (SHI), gancaonin M, and glyasperin B, as the main bioactive components of BZYQD, had good binding affinity with hub target proteins. DGC and SHI treatment could significantly inhibit the injury of neurons and inflammatory response of microglia stimulated by oxidized low-density lipoprotein (ox-LDL), respectively. In summary, BZYQD and its main bioactive components DGC and SHI show good potential to ameliorate the symptoms of NB.

The pantothenic acid derivative dexpanthenol ameliorated doxorubicin-induced neurotoxicity via regulating AKT/CREB/BDNF and AKT/NRF2 signaling pathways

BACKGROUND

Doxorubicin (Dox)-induced neurotoxicity is a well-documented side effect of chemotherapy. Dexpanthenol (Dex), an analog of vitamin B5, has shown protective properties. This study aimed to explore the molecular mechanisms by which Dex mitigates Dox-induced neurotoxicity, particularly through the protein kinase B (AKT)/cyclic AMP-response element-binding protein (CREB)/brain-derived neurotrophic factor (BDNF) pathway and nuclear factor erythroid 2-related factor 2 (NRF2) signaling.

METHODS AND RESULTS

The experiment was conducted using four groups: control, Dex, Dox, and Dox + Dex, comprising a total of 32 female Wistar Albino rats. After two weeks of treatment, the rats were euthanized, and brain and cerebellum tissues were collected for analysis. Biochemical analysis was performed spectrophotometrically to assess oxidative stress parameters, while histological and immunostaining analyses focused on nuclear factor kappa B (NF-κB) and inducible nitric oxide synthase (iNOS) immunoexpressions. Genetic analysis of AKT, CREB, BDNF, and NRF2 gene expressions was conducted using real-time polymerase chain reaction. Histopathological evaluation of the Dox group revealed hyperemia, microhemorrhage, neuronal damage, and neuronophagia. Additionally, an increase in caspase-3, tumor necrosis factor-alpha, NF-κB, and iNOS immunoexpressions were observed, along with elevated total oxidant status and oxidative stress index. A decrease in AKT, CREB, BDNF, and NRF2 gene expressions accompanied these changes. Dex treatment significantly reversed these pathological findings, effectively protecting the brain from Dox-induced neuronal damage.

CONCLUSION

In conclusion, Dex may provide neuroprotection in female rats with Dox-induced neurotoxicity by activating the CREB/BDNF pathway and reducing oxidative stress through AKT-mediated NRF2 synthesis. Further detailed studies exploring additional pathways are required to incorporate Dex into cancer treatment protocols and minimize side effects.

Astrocytic NLRP3 cKO mitigates depression-like behaviors induced by mild TBI in mice

BACKGROUND

Reports indicate that depression is a common mental health issue following traumatic brain injury (TBI). Our prior research suggests that Nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3)-related neuroinflammation, modulated by glial cells such as astrocytes, is likely to play a crucial role in the progression of anxiety and cognitive dysfunction. However, there is limited understanding of the potential of astrocytic NLRP3 in treating depression under mild TBI condition. This study aimed to determine whether astrocytic NLRP3 knockout (KO) could mitigate depressive-like behaviors following mild TBI and explore potential variations in such behaviors between genders post-mild TBI.

METHODS

Mild TBI was induced in mice using Feeney's weight-drop method. Behavioral assessments included neurological severity scores (NSS), social interaction test (SI), tail suspension test (TST), and forced swimming test (FST). Pathological changes were evaluated through immunofluorescence and local field potential (LFP) recordings at various time points post-injury.

RESULTS

Our findings indicated that astrocyte-specific NLRP3 KO decreased cleaved caspase-1 colocalized with astrocytes, decreased pathogenic astrocytes and increased Postsynaptic density protein 95 (PSD95) intensity, and significantly alleviated mild TBI-induced depression-like behaviors. It also led to the upregulation of protective astrocytes and apoptosis-associated factors, including cleaved caspase-3 post-mild TBI. Additionally, astrocyte-specific NLRP3 deletion resulting in improved θ and γ power and θ-γ phase coupling in the social interaction test (SI). Notably, under mild TBI conditions, astrocyte-specific NLRP3 exhibited greater neuroprotective effects in female knockout mice compared to males.

CONCLUSION

Astrocyte NLRP3 knockout demonstrated a protective mechanism in mice subjected to mild TBI, possibly attributed to the inhibition of pyroptosis through the NLRP3 signaling pathway in astrocytes.

Reversing Persistent PTEN Activation after Traumatic Brain Injury Fuels Long-Term Axonal Regeneration via Akt/mTORC1 Signaling Cascade

Traumatic brain injury (TBI) often leads to enduring axonal damage and persistent neurological deficits. While PTEN's role in neuronal growth is recognized, its long-term activation changes post-TBI and its effects on sensory-motor circuits are not well understood. Here, it is demonstrated that the neuronal knockout of PTEN (PTEN-nKO) significantly enhances both structural and functional recovery over the long term after TBI. Importantly, in vivo, DTI-MRI revealed that PTEN-nKO promotes white matter repair post-TBI. Additionally, calcium imaging and electromyographic recordings indicated that PTEN-nKO facilitates cortical remapping and restores sensory-motor pathways. Mechanistically, PTEN negatively regulates the Akt/mTOR pathway by inhibiting Akt, thereby suppressing mTOR. Raptor is a key component of mTORC1 and its suppression impedes axonal regeneration. The restoration of white matter integrity and the improvements in neural function observed in PTEN-nKO TBI-treated mice are reversed by a PTEN/Raptor double knockout (PTEN/Raptor D-nKO), suggesting that mTORC1 acts as a key mediator. These findings highlight persistent alterations in the PTEN/Akt/mTORC1 axis are critical for neural circuit remodeling and cortical remapping post-TBI, offering new insights into TBI pathophysiology and potential therapeutic targets.

Melatonin Regulates Glymphatic Function to Affect Cognitive Deficits, Behavioral Issues, and Blood-Brain Barrier Damage in Mice After Intracerebral Hemorrhage: Potential Links to Circadian Rhythms

BACKGROUND

Intracerebral hemorrhage (ICH) is a life-threatening cerebrovascular disorder with no specific pharmacological treatment. ICH causes significant behavioral deficits and cognitive impairments. Recent research suggests that circadian rhythm regulation could be a promising therapeutic strategy for ICH. Melatonin has been shown to alleviate glymphatic system (GS) dysfunction by regulating circadian rhythms, thereby improving depressive-like behaviors and postoperative sleep disorders in mice. However, its application in ICH treatment and specific mechanisms are not well understood.

METHODS

ICH models were created in 8-to-10-week-old mice using collagenase injection. Circadian rhythm modulation was tested with melatonin and luzindole. Behavioral and cognitive impairments were assessed with the modified neurological severity score, corner test, and novel object recognition test. Brain water content was measured by the dry/wet weight method, and cerebral perfusion was assessed by cerebral blood flow measurements. GS function was evaluated using RITC-dextran and Evans blue assays. Immunofluorescence and western blotting were used to analyze GS function and BBB permeability.

RESULTS

Melatonin restored GS transport after ICH, promoting hematoma and edema absorption, reducing BBB damage, and improving cognitive and behavioral outcomes. However, luzindole partially blocked these benefits and reversed the neuroprotective effects.

CONCLUSION

Melatonin and luzindole treatment affect GS function, BBB permeability, and cognitive-behavioral outcomes in mice with ICH. The underlying mechanism may involve the regulation of circadian rhythms.

Partially hydrolyzed guar gum alleviates neurological deficits and gastrointestinal dysfunction in mice with traumatic brain injury

Traumatic brain injury (TBI)-associated neuroinflammation and neurotoxicity can induce gastrointestinal dysfunction through the brain-gut axis. Partially hydrolyzed guar gum (PHGG) was demonstrated to exert beneficial health effects by altering gut microbiota and short-chain fatty acids (SCFAs) production. Our study aimed to explore the effects of PHGG on gastrointestinal dysfunction in TBI mouse models. Controlled cortical impact (CCI)-induced TBI mouse models were administrated with PHGG (600 mg/kg/d) for 21 consecutive days. Behavioral tests (modified neurological severity score and beam walk test) and Y‑maze assay were performed to evaluate neurological functions and cognitive impairment. Enzyme-linked immunosorbent assay, reverse transcription-quantitative polymerase chain reaction, and western blotting examined the levels of inflammatory cytokines, intestinal mucosal damage markers, intestinal tight junction proteins, and NLRP3 inflammasome-related molecules in the serum, cerebral cortex, and colon tissues. The histological changes in the cerebral cortex and colon tissues were observed through hematoxylin and eosin and Nissl staining. Liquid chromatography/mass spectrometry analyzed SCFA amounts in the cecum contents and bile acid levels in the serum. PHGG administration alleviated neurological deficits and cognitive perturbations, reduced neuroinflammation, and attenuated cortical tissue damage and neuron loss in TBI mice. PHGG ameliorated intestinal barrier impairment, upregulated intestinal production of SCFAs, and elevated serum bile acid levels in TBI mice. Besides, PHGG treatment repressed NLRP3 inflammasome activation in TBI mice. Overexpressing NLRP3 reversed the beneficial effects of PHGG against TBI in mice. PHGG ameliorates neuroinflammation and gastrointestinal dysfunction in TBI murine models by inhibiting NLRP3 inflammasome activation.

Neuroprotective effects of hypidone hydrochloride (YL-0919) after traumatic brain injury in mice

BACKGROUND

Neurological dysfunction is a common complication of traumatic brain injury (TBI), and early treatments are critical for the long-term prognosis. This study aimed to investigate whether hypidone hydrochloride (YL-0919) improves neurological function impairment in mice with TBI.

METHODS

TBI was induced in adult male C57BL/6J mice using the controlled cortical impact (CCI) method. First, the modified neurological severity score (mNSS), rotarod test, and Morris water maze (MWM) test were conducted to assess the impact of YL-0919 on neurological function in mice with TBI. Next, immunofluorescence and laser speckle contrast imaging were utilized to measure the number and activation of microglia and cerebral blood flow (CBF) after TBI. Enzyme-linked immunosorbent assays (ELISAs) were employed to assess the inflammatory factors. Finally, Western blotting was performed to measure the expression of proteins. Golgi-Cox staining was utilized to investigate the structure of pyramidal neurons.

RESULTS

YL-0919 significantly alleviated neurological dysfunction in TBI+YL-0919 mice compared with TBI+Vehicle mice, increased the time spent on the rotarod (F = 1.297, P <0.05), and partially relieved cognitive dysfunction in TBI mice (for mNSS, F = 5.540, P <0.01; for MWM test, F = 30.78, P <0.05). Additionally, YL-0919 effectively inhibited the proliferation and activation of microglia (both P <0.01), promoted the recovery of CBF around the brain injury site and inhibited the expression of tumor necrosis factor-α (F = 9.142, P <0.05) and IL-1β (F = 4.662, P <0.05), and increased the concentration of IL-4 (F = 5.172, P <0.05). Furthermore, continuous gavage of YL-0919 (2.5 mg/kg) for seven days effectively increased the protein expression of brain-derived neurotrophic factor (BDNF), promoted the phosphorylation of mammalian target of rapamycin (mTOR), increased postsynaptic density protein 95 (PSD95) and synapsin1 levels, and increased the neuronal dendritic complexity and the dendritic spine density around the brain injury site (all P <0.05).

CONCLUSIONS

Our findings indicated that YL-0919 can ameliorate neurological dysfunction in mice after TBI through the suppression of inflammation and the stimulation of the BDNF-mTOR signaling pathway. These findings provide an insightful perspective on the potential pharmacological mechanism involved in the neuroprotective effect of YL-0919.

TREM2 affects DAM-like cell transformation in the acute phase of TBI in mice by regulating microglial glycolysis

BACKGROUND

Traumatic brain injury (TBI) is characterized by high mortality and disability rates. Disease-associated microglia (DAM) are a newly discovered subtype of microglia. However, their presence and function in the acute phase of TBI remain unclear. Although glycolysis is important for microglial differentiation, its regulatory role in DAM transformation during the acute phase of TBI is still unclear. In this study, we investigated the functions of DAM-like cells in the acute phase of TBI in mice, as well as the relationship between their transformation and glycolysis.

METHODS

In this study, a controlled cortical impact model was used to induce TBI in adult male wild-type (WT) C57BL/6 mice and adult male TREM2 knockout mice. Various techniques were used to assess the role of DAM-like cells in TBI and the effects of glycolysis on DAM-like cells, including RT‒qPCR, immunofluorescence assays, behavioural tests, extracellular acidification rate (ECAR) tests, Western blot analysis, cell magnetic sorting and culture, glucose and lactate assays, and flow cytometry.

RESULTS

DAM-like cells were observed in the acute phase of TBI in mice, and their transformation depended on TREM2 expression. TREM2 knockout impaired neurological recovery in TBI mice, possibly due in part to their role in clearing debris and secreting VEGFa and BDNF. Moreover, DAM-like cells exhibited significantly increased glycolytic activity. TREM2 regulated the AKT‒mTOR‒HIF-1α pathway and glycolysis in microglia in the acute phase of TBI. The increase in glycolysis in microglia partially contributed to the transformation of DAM-like cells in the acute phase of TBI in mice.

CONCLUSIONS

Taken together, the results of our study demonstrated that DAM-like cells were present in the acute phase of TBI in mice. TREM2 might influence DAM-like cell transformation by modulating the glycolysis of microglia. Our results provide a new possible pathway for intervening TBI.

Effects of PPARG on the proliferation, apoptosis, and estrogen secretion in goat granulosa cells

As a member of peroxisome proliferator-activated receptor (PPAR) family, PPARG has been reported to be involved in glucolipid metabolism in various species. However, the function of PPARG in estradiol (E2) synthesis, apoptosis, and proliferation in goat ovarian granulosa cells (GCs) is unclear. In this study, we found that goat PPARG was expressed in GCs of all grades of follicles, and localized in the cytoplasm and nucleus of GCs. Transfection of small interfering RNA-PPARG2 (si-PPARG2) decreased E2 synthesis and the abundances of HSD3B and CYP19A1 mRNA and protein. It also promoted cell apoptosis with significant increases in the ratio of BAX/BCL-2 and Caspase3 mRNA and protein. Meanwhile, cell cycle was inhibited by si-PPARG2 transfection, accompanied by decreased mRNA levels of CDK4, CKD6, MYC, CCND1, CCND2, PCNA, and CCNB, increased mRNA level of P53, and decreased protein levels of CDK4, MYC, and CCND1. Furthermore, PPARG interference affected the mRNA and protein abundances of CREB as well as the phosphorylation of CREB but not PKA. In conclusion, our data suggest that PPARG plays an important role in regulating E2 synthesis, cell apoptosis, and proliferation of goat GCs, including the CREB expression and phosphorylation. These results provide evidences for the in-depth study of PPARG in the regulation of goat GCs function.

Trem2/Tyrobp Signaling Protects Against Aortic Dissection and Rupture by Inhibiting Macrophage Activation in Mice

BACKGROUND

The development of aortic dissection (AD) is closely associated with inflammation. The Trem2 (triggering receptor expressed on myeloid cells 2)/Tyrobp (TYRO protein tyrosine kinase-binding protein) signaling pathway critically regulates innate immunity and has emerged as an important target in cardiovascular diseases; however, its role in AD remains unclear.

METHODS

Transcriptome data from human and mouse ADs were used to perform differentially expressed gene-based protein-protein interaction network analyses. Tyrobp knockout (Tyrobp-/-), myeloid cell-specific Tyrobp-/- (Tyrobpfl/fl Lyz2cre), and Trem2 knockout (Trem2-/-) mice were given β-aminopropionitrile monofumarate in drinking water to induce AD. To dissect the role of macrophages in Tyrobp deficiency-mediated AD progression, macrophages were depleted using clodronate liposomes. Bulk and single-cell RNA sequencing, immunofluorescence staining, and quantitative real-time polymerase chain reaction were performed to assess inflammation and the underlying mechanisms of Tyrobp in AD.

RESULTS

Network analysis identified Tyrobp as a hub gene of AD, with elevated levels observed in both human and mouse ADs. Global deletion and myeloid cell-specific deficiency of Tyrobp in mice significantly increased AD incidence and exacerbated extracellular matrix degradation and macrophage infiltration within the aortic wall. Macrophage depletion mitigated the adverse effects of Tyrobp deficiency on AD progression. Additionally, Tyrobp deficiency enhanced TLR (Toll-like receptor)-4 signaling and macrophage activation, which were abrogated by TLR4 inhibitors. Furthermore, deletion of the Tyrobp-associated receptor Trem2 significantly aggravated mouse AD development, whereas Trem2 agonist treatment conferred protection against AD.

CONCLUSIONS

Our findings suggest a novel role for the Trem2/Tyrobp axis in AD development in mice. Enhancement of Trem2/Tyrobp signaling may represent a promising strategy for the prevention and treatment of AD. Future studies to clarify the role of Trem2/Tyrobp in human AD are warranted.

Early disruption of the CREB pathway drives dendritic morphological alterations in FTD/ALS cortical neurons

Synaptic loss and dendritic degeneration are common pathologies in several neurodegenerative diseases characterized by progressive cognitive and/or motor decline, such as Alzheimer's disease (AD) and frontotemporal dementia/amyotrophic lateral sclerosis (FTD/ALS). An essential regulator of neuronal health, the cAMP-dependent transcription factor CREB positively regulates synaptic growth, learning, and memory. Phosphorylation of CREB by protein kinase A (PKA) and other cellular kinases promotes neuronal survival and maturation via transcriptional activation of a wide range of downstream target genes. CREB pathway dysfunction has been strongly implicated in AD pathogenesis, and recent data suggest that impaired CREB activation may contribute to disease phenotypes in FTD/ALS as well. However, the mechanisms behind reduced CREB activity in FTD/ALS pathology are not clear. In this study, we found that cortical-like neurons derived from iPSC lines carrying the hexanucleotide repeat expansion in the C9ORF72 gene, a common genetic cause of FTD/ALS, displayed a diminished activation of CREB, resulting in decreased dendritic and synaptic health. Importantly, we determined such impairments to be mechanistically linked to an imbalance in the ratio of regulatory and catalytic subunits of the CREB activator PKA and to be conserved in C9-ALS patient's postmortem tissue. Modulation of cAMP upstream of this impairment allowed for a rescue of CREB activity and an amelioration of dendritic morphology and synaptic protein levels. Our data elucidate the mechanism behind early CREB pathway dysfunction and discern a feasible therapeutic target for the treatment of FTD/ALS and possibly other neurodegenerative diseases.

Hsa_circ_0004776 regulates the retina neovascularization in progression of diabetic retinopathy via hsa-miR-382-5p/BDNF axis

The aim of this work was to identify the regulatory function of hsa_circ_0004776 in the progression of diabetic retinopathy (DR). The direct interactions between hsa_circ_0004776 and hsa-miR-382-5p and between hsa-miR-382-5p and BDNF, were confirmed via dual-luciferase reporter assays. Quantitative Real-Time PCR analysis indicated that hsa_circ_0004776 was highly expressed in aqueous humour samples of DR patients and human retinal microvascular epithelial cells (hRECs) under a high-glucose environment, whereas hsa-miR-382-5p showed the opposite trend. Overexpressed hsa_circ_0004776 significantly enhanced DNA synthesis, proliferation, migration, and tube formation in hRECs in hyperglycaemia, while hsa-miR-382-5p mimics reversed these changes. Additionally, in a streptozotocin-induced Sprague-Dawley rat model of DR, vitreous microinjection of rno-miR-382-5p agomir reversed the pathologic features in the progression of DR, including retinal vascular leakage, capillary decellularization, loss of pericytes, fibrosis, and gliosis. Our results indicated that under hyperglycaemic conditions, hsa_circ_0004776 influences the progression of DR via hsa-miR-382-5p and thus represents a potential therapeutic target.

Jiawei Xionggui Decoction promotes meningeal lymphatic vessels clearance of β-amyloid by inhibiting arachidonic acid pathway

BACKGROUND

Alzheimer's disease (AD) is an aging-associated form of dementia characterized by the pathological deposition of toxic misfolded proteins in the central nervous system (CNS), which is closely related to the clearance impairment of meningeal lymphatic vessels (mLVs). Thus, enhancement dural meningeal lymphatic drainage to remove amyloid-β (Aβ) is usually considered as a potential therapeutic target for AD.

PURPOSE

This study aimed to investigate the mechanisms of Jiawei Xionggui Decoction (JWXG) to attenuate cognitive dificits in APP/PS1 mice with impaired meningeal lymphatic drainage.

METHODS

Ligation of deep cervical lymph nodes (dcLNs) was performed to establish the mice model of the impaired meningeal lymphatic drainage in APP/PS1 mice. Cognitve behaviors and pathological morphology of mice were assessed. Cerebral blood flow (CBF) of mice was determined using Laser speckle contrast imaging analysis. Serum non-targeted metabolomics analysis was applied to decipher the mechanisms of JWXG in rescuing the impairment of mLVs, and C8-D1A cells were employed to validate in vitro.

RESULTS

Disruption of mLVs in APP/PS1 mice deteriorated cognitive dysfunction, accelerated Aβ burden and glia activation, accompanied by more severe neuropathological damage, CBF reduction and neuroinflammation exacerbation. Serum non-targeted metabolomics analysis indicates the increase of arachidonic acid (AA) metabolic pathway was the key contributor to the neuropathological exacerbation of dcLNs ligation APP/PS1 mice. Interestingly, clinically equivalent dose of JWXG was sufficient to restore mLVs drainage and rescue cognitive performance by inhibiting neuroinflammation depended by AA metabolic pathway in dcLNs ligation APP/PS1 mice.

CONCLUSION

Our findings establish a novel mechanism that rescue mLVs by inhibiting AA metabolic pathway to clear brain Aβ, and support JWXG as a feasible treatment strategy for AD by suppressing AA metabolic pathway to improve mLVs drainage efficiency.

The therapeutic potential of Apigenin in amyotrophic lateral sclerosis through ALDH1A2/Nrf2/ARE signaling

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by motor neuron loss leading to muscle weakness and atrophy. Apigenin (APG), known for its antioxidant properties, holds potential as a therapeutic compound in ALS.

METHODS

We used the Tg(SOD1*G93A)1Gur/J transgenic mouse model of ALS to investigate the therapeutic effects of APG. Key measured included motor function via the ALSTDI score, molecular markers of oxidative stress (OS) and apoptosis in spinal cord tissues. Techniques used included pathological, Western blotting, flow cytometry, and qRT-PCR to assess the effect of ALDH1A2.

RESULTS

APG treatment attenuated weight loss and improved motor function scores in ALS mice compared to untreated ALS models. Molecular analyses revealed a significant upregulation of ALDH1A2 in APG-treated groups, along with a reduction in markers of OS and apoptosis. In vitro studies in NSC34 cells further confirmed the protective effects of APG against SOD1*G93A mutation-induced cytotoxicity. In addition, suppression of ALDH1A2 by shRNA exacerbated disease markers that were ameliorated by APG treatment.

CONCLUSIONS

Our results suggest that APG attenuates the progression of ALS pathology by regulating OS and apoptosis through ALDH1A2. These results support further investigation of APG as a potential therapeutic agent for the treatment of ALS.

TREM2, a critical activator of pyroptosis, mediates the anti‑tumor effects of piceatannol in uveal melanoma cells via caspase 3/GSDME pathway

Uveal melanoma (UM) is the most prevalent type of primary intraocular malignancy and is prone to metastasize, particularly to the liver. However, due to the poor understanding of the pathogenesis of UM, effective therapeutic approaches are lacking. As a phenolic compound extracted from grapes, piceatannol (PIC) exhibits anti‑cancer properties. To the best of our knowledge, however, the effects of PIC on UM have not been well investigated. Therefore, in the present study, considering the impact of pyroptosis on modulating cell viability, the mechanism underlying the effects of PIC on UM cell proliferation was explored. The inhibitory effect of PIC on proliferation of UM cells was detected by cell counting kit‑8 assay. Wound healing was used to investigate the effects of PIC on the migration of UM cells. Activity detecting assays were performed to test the apoptosis and oxidant level in UM cells. Western blotting and RT‑qPCR were used to detect the inflammatory and pyroptotic levels of UM cell after PIC treatment. PIC‑treated UM cells were screened by high‑throughput sequencing to detect the differential expression of RNA and differential genes. Si‑TREM2 transfection was used to verify the important role of TREM2 in the effects of PIC. Immunohistochemical staining was used to observe the expressions of TREM2 and GSDMR of tumor in nude mice after PIC administration. PIC effectively inhibited proliferation ability of C918 and Mum‑2b UM cell lines via enhancing apoptosis, as evidenced by enhanced activities of caspase 3 and caspase 9. In addition, treatment of UM cells with PIC attenuated cell migration in a dose‑dependent manner. PIC increased reactive oxygen species levels and suppressed the activity of the antioxidant enzymes superoxide dismutase, glutathione‑S‑transferase, glutathione peroxidase and catalase. PIC inhibited inflammatory responses in C918 cells. PIC treatment upregulated IL‑1β, IL‑18 and Nod‑like receptor protein 3 and downregulated gasdermin D (GSDMD). RNA sequencing results revealed the activation of an unconventional pyroptosis‑associated signaling pathway, namely caspase 3/GSDME signaling, following PIC treatment, which was mediated by triggering receptor expressed on myeloid cells 2 (TREM2) upregulation. As an agonist of TREM2, COG1410‑mediated TREM2 upregulation inhibited proliferation of C918 cells, displaying similar effects to PIC. Furthermore, PIC inhibited tumor growth via regulating the TREM2/caspase 3/GSDME pathway in a mouse model. Collectively, the present study revealed a novel mechanism underlying the inhibitory effects of PIC on UM, providing a potential treatment approach for UM in clinic.

The Function and Mechanism of Laminaripentaose Prepared from Curdlan for the Amelioration of the Cognitive Dysfunctions in Obese Mice

Functional oligosaccharides induce specific alterations in gut microbiota, potentially providing physiological benefits. However, the effects of laminaripentaose (LPA) on metabolic syndrome and the mechanism underlying it have not been intensively investigated yet. This study aimed to determine the effects of LPA on obesity and obesity-induced cognition impairment in mice. C57BL/6N mice fed with a high-fat diet received an LPA treatment for 12 weeks. An antibiotic intervention was further applied to evaluate the effects of the gut microbiota on cognitive functions. LPA treatment (500 mg/kg) reduced the weight gain by 32.4%. Furthermore, LPA improved memory functions and reduced hippocampal insulin resistance and neuronal injury. LPA markedly reduced systemic low-grade inflammation and intestinal barrier injury. Moreover, LPA increased gut beneficial bacteria, and Butyricimonas and Bifidobacterium were increased by 94.0 and 422.7%, respectively, accompanied by increased fecal short-chain fatty acids. Interestingly, antibiotic cocktail treatment abrogated the beneficial effects of LPA on cognition, which further suggests that LPA may attenuate obesity-induced cognition impairment via the gut-brain axis. Our findings provide the first evidence for the potential of dietary LPA to prevent obesity and obesity-associated complications.

TREM2 alleviates long-term cognitive dysfunction after subarachnoid hemorrhage in mice by attenuating hippocampal neuroinflammation via PI3K/Akt signaling pathway

Subarachnoid hemorrhage (SAH) often leads to long-term cognitive deficits in patients, particularly due to injury to brain regions such as the hippocampus. This study aims to investigate the role of the triggering receptor expressed on myeloid cells 2 (TREM2) in mitigating hippocampal injury and associated cognitive impairments following SAH. To explore the protective effects of TREM2, we utilized the TREM2 agonist COG1410 to upregulate TREM2 expression and employed TREM2 knockout (KO) mice to verify the necessity of TREM2 for this protective role. The study further examined the involvement of the PI3K/Akt signaling pathway in TREM2-mediated neuroprotection. Our findings indicate that the upregulation of TREM2 significantly alleviated long-term cognitive deficits and promoted the recovery of hippocampal neural activity post-SAH. The neuroprotective effects were linked to reduced microglial activation and decreased secretion of inflammatory factors within the hippocampus. In contrast, TREM2 KO mice did not exhibit these protective effects. Furthermore, inhibition of the PI3K/Akt pathway also diminished these protective effects of TREM2 upregulation and worsened cognitive outcomes. In conclusion, TREM2 upregulation mitigates long-term cognitive dysfunction following SAH by attenuating hippocampal neuroinflammation via the PI3K/Akt signaling pathway. These findings suggest that TREM2 could be a potential therapeutic target for improving cognitive outcomes after SAH.

The role of microglial TREM2 in development: A path toward neurodegeneration?

The nervous and the immune systems undergo a continuous cross talk, starting from early development and continuing throughout adulthood and aging. Defects in this cross talk contribute to neurodevelopmental and neurodegenerative diseases. Microglia are the resident immune cells in the brain that are primarily involved in this bidirectional communication. Among the microglial genes, trem2 is a key player, controlling the functional state of microglia and being at the forefront of many processes that require interaction between microglia and other brain components, such as neurons and oligodendrocytes. The present review focuses on the early developmental window, describing the early brain processes in which TREM2 is primarily involved, including the modulation of synapse formation and elimination, the control of neuronal bioenergetic states as well as the contribution to myelination processes and neuronal circuit formation. By causing imbalances during these early maturation phases, dysfunctional TREM2 may have a striking impact on the adult brain, making it a more sensitive target for insults occurring during adulthood and aging.

Network pharmacology and molecular docking-based investigation of monocyte locomotion inhibitory factor attenuates traumatic brain injury by regulating aquaporin 4 expression

Traumatic brain injury (TBI) is a significant cause of disability and mortality worldwide, and effective treatment options are currently limited. Monocyte locomotion inhibitor factor (MLIF), a small molecular pentapeptide, has demonstrated a protective effect against cerebral ischemia. This study aimed to investigate the protective effects of MLIF on TBI and explore its underlying mechanism of action. In animal experiments, we observed that administration of MLIF after TBI reduced brain water content and improved brain edema, suggesting a certain degree of protection against TBI. By utilizing network pharmacology methodologies, we employed target screening techniques to identify the potential targets of MLIF in the context of TBI. As a result, we successfully enriched ten signaling pathways that are closely associated with TBI. Furthermore, using molecular docking techniques, we identified AQP4 as one of the top ten central genes discovered in this study. Eventually, our study demonstrated that MLIF exhibits anti-apoptotic properties and suppresses the expression of AQP4 protein, thus playing a protective role in traumatic brain injury. This conclusion was supported by TUNEL staining and the evaluation of Bcl-2, Bax, and AQP4 protein levels. These discoveries enhance our comprehension of the mechanisms by which MLIF exerts its protective effects and highlight its potential as a promising therapeutic intervention for TBI treatment.

Transcriptomic analysis reveals novel hub genes associated with astrocyte autophagy in intracerebral hemorrhage

Introduction

Neuroinflammation serves as a critical local defense mechanism against secondary brain injury following intracerebral hemorrhage (ICH), and astrocytes play a prominent role in this process. In this study, we investigated astrocytic changes during the inflammatory state after ICH to identify new targets for improving the inflammatory response.

Methods

We stimulated mouse astrocytes with lipopolysaccharide (LPS) in vitro and analyzed their transcriptomes via ribonucleic acid sequencing. We created an ICH model in living organisms by injecting autologous blood.

Results

RNA sequencing revealed that 2,717 genes were differentially expressed in the LPS group compared to those in the saline group, with notable enrichment of the autophagic pathway. By intersecting the 2,717 differentially expressed genes (DEGs) with autophagy-related genes, we identified 36 autophagy-related DEGs and seven hub genes. Previous studies and quantitative reverse transcription-polymerase chain reaction results confirmed the increased expression of phosphatidylinositol 3-kinase catalytic subunit type 3 (Pik3c3), AKT serine/threonine kinase 1 (Akt1), and unc-51 like autophagy activating kinase 2 (Ulk2) in astrocytes after ICH. Transcription factors and target miRNAs were identified for the final three DEGs, and 3-methyladenine and leupeptin were identified as potential therapeutic agents for ICH.

Conclusion

Our findings suggest that astrocyte autophagy plays a critical role in ICH complexity, and that Pik3c3, Akt1, and Ulk2 may be potential therapeutic targets.

Intermittent hypoxia exacerbates anxiety in high-fat diet-induced diabetic mice by inhibiting TREM2-regulated IFNAR1 signaling

BACKGROUND

Type 2 diabetes mellitus (T2DM) and obstructive sleep apnea (OSA) are mutual risk factors, with both conditions inducing cognitive impairment and anxiety. However, whether OSA exacerbates cognitive impairment and anxiety in patients with T2DM remains unclear. Moreover, TREM2 upregulation has been suggested to play a protective role in attenuating microglia activation and improving synaptic function in T2DM mice. The aim of this study was to explore the regulatory mechanisms of TREM2 and the cognitive and anxiety-like behavioral changes in mice with OSA combined with T2DM.

METHODS

A T2DM with OSA model was developed by treating mice with a 60% kcal high-fat diet (HFD) combined with intermittent hypoxia (IH). Spatial learning memory capacity and anxiety in mice were investigated. Neuronal damage in the brain was determined by the quantity of synapses density, the number and morphology of brain microglia, and pro-inflammatory factors. For mechanism exploration, an in vitro model of T2DM combined with OSA was generated by co-treating microglia with high glucose (HG) and IH. Regulation of TREM2 on IFNAR1-STAT1 pathway was determined by RNA sequencing and qRT-PCR.

RESULTS

Our results showed that HFD mice exhibited significant cognitive dysfunction and anxiety-like behavior, accompanied by significant synaptic loss. Furthermore, significant activation of brain microglia and enhanced microglial phagocytosis of synapses were observed. Moreover, IH was found to significantly aggravate anxiety in the HFD mice. The mechanism of HG treatment may potentially involve the promotion of TREM2 upregulation, which in turn attenuates the proinflammatory microglia by inhibiting the IFNAR1-STAT1 pathway. Conversely, a significant reduction in TREM2 in IH-co-treated HFD mice and HG-treated microglia resulted in the further activation of the IFNAR1-STAT1 pathway and consequently increased proinflammatory microglial activation.

CONCLUSIONS

HFD upregulated the IFNAR1-STAT1 pathway and induced proinflammatory microglia, leading to synaptic damage and causing anxiety and cognitive deficits. The upregulated TREM2 inT2DM mice brain exerted a negative regulation of the IFNAR1-STAT1 pathway. Mice with T2DM combined with OSA exacerbated anxiety via the downregulation of TREM2, causing heightened IFNAR1-STAT1 pathway activation and consequently increasing proinflammatory microglia.

Activation of Wnt signaling mitigates blood-brain barrier disruption by inhibiting vesicular transcytosis after traumatic brain injury in mice

Elevated transport of Caveolin-1 (CAV-1) vesicles within vascular endothelial cells constitutes a significant secondary pathogenic event contributing to the compromise of the blood-brain barrier (BBB) post-traumatic brain injury (TBI). While Wnt/β-catenin signaling is recognized for its critical involvement in angiogenesis and the maintenance of BBB integrity, its influence on vascular endothelial transcytosis in the aftermath of TBI is not well-defined. This study aims to elucidate the impact of Wnt/β-catenin signaling on cerebrovascular vesicular transcytosis following TBI. In this experiment, adult male wild-type (WT) C57BL/6 mice underwent various interventions. TBI was induced utilizing the controlled cortical impact technique. Post-TBI, mice were administered either an inhibitor or an agonist of Wnt signaling via intraperitoneal injection. Recombinant adeno-associated virus (rAAV) was administered intracerebroventricularly to modulate the expression of the CAV-1 inhibitory protein, Major facilitator superfamily domain-containing 2a (Mfsd2a). This research utilized Evans blue assay, Western blot analysis, immunofluorescence, transmission electron microscopy, and neurobehavioral assessments. Post-TBI observations revealed substantial increases in macromolecule (Evans blue and albumin) leakage, CAV-1 transport vesicle count, astrocyte end-feet edema, and augmented aquaporin-4 (AQP4) expression, culminating in BBB disruption. The findings indicate that Wnt signaling pathway inhibition escalates CAV-1 transport vesicle activity and aggravates BBB compromise. Conversely, activating this pathway could alleviate BBB damage by curtailing CAV-1 vesicle presence. Post-TBI, there is a diminution in Mfsd2a expression, which is directly influenced by the modulation of WNT signals. Employing a viral approach to regulate Mfsd2a, we established that its down-regulation undermines the protective benefits derived from reducing CAV-1 transport vesicles through WNT signal enhancement. Moreover, we verified that the WNT signaling agonist LiCl notably ameliorates neurological deficits following TBI in mice. Collectively, our data imply that Wnt/β-catenin signaling presents a potential therapeutic target for safeguarding against BBB damage and enhancing neurological function after TBI.

Therapeutic potential of CB1R activation by Qingyangshen glycoside M1 for seizure relief

ETHNOPHARMACOLOGICAL RELEVANCE

Cynanchum otophyllum C.K.Schneid.PI.Wilson, commonly referred as ''Qingyangshen'' (QYS), is a traditional folk medicine from Yunnan, renowned for its efficacy in neurological and psychiatric disorders. Glycosides isolated from QYS have shown promise in alleviating epilepsy, however, mechanisms of action and specific molecular targets remain to be elucidated.

AIM OF THE STUDY

The study aimed to evaluate the anticonvulsant effects of Qingyangshen glycosides M1 (M1), a C21 steroidal glycoside from QYS, on pentylenetetrazol (PTZ)-induced convulsions in zebrafish (Danio rerio), and its neuroprotective effect on Glutamate (Glu)-induced damage to PC12 cells, and importantly to identify its potential molecular targets.

MATERIALS AND METHODS

To evaluate anticonvulsant activity of M1, 7 days-post-fertilization (7-dpf) animals were pretreated (by immersion) and then exposed to PTZ (10 mM) solution. Furthermore, Glu-induced PC12 cell damage was employed to investigate the neuroprotective and anti-apoptotic capacity. Cells were pretreated with various concentrations of M1 (0-10 μM) for 12 h and then co-treated with Glu (15 mM) for an additional 24 h. The cell viability, apoptosis rate and apoptosis-related proteins (p-PI3K, PI3K, Akt, p-Akt, CREB, p-CREB, BDNF, Bax and Bcl-2) were measured using CCK-8, annexin V/PI and Western blot assays. To model the expected interaction between M1 and candidate cannabinoid receptor type 1 (CB1R), ERK phosphorylation, molecular docking, and drug affinity responsive target stability (DARTS) techniques were employed. Finally, CB1R antagonist Rimonabant (Rim) was validated by co-administration in both zebrafish and cells to confirm the requirement of CB1R for M1 efficacy.

RESULTS

At a concentration of 400 μM, M1 dramatically reversed PTZ-induced convulsive-like behaviors in zebrafish, as evidenced by a significant reduction in locomotor activity. In the context of Glu-induced cytotoxicity, M1 (10 μM) demonstrated a notable increase in cell viability and suppressed apoptosis through modulation of the Bax/Bcl-2 ratio and activation of the PI3K/Akt/CREB/BDNF signaling axis. These effects were facilitated through CB1R activation. In contrast, Rim dampened the beneficial activities of M1 as a cannabinoid agonist.

CONCLUSIONS

These results demonstrated that M1 as a potential CB1R activator, exhibiting anticonvulsive effects in a PTZ-induced zebrafish model and neuroprotective properties via the PI3K/Akt/CREB/BDNF signaling axis in a Glu-induced PC12 cell injury model. Notably, the observed seizure relief attenuated by CB1R chemical antagonism.

Prevotella copri transplantation promotes neurorehabilitation in a mouse model of traumatic brain injury

BACKGROUND

The gut microbiota plays a critical role in regulating brain function through the microbiome-gut-brain axis (MGBA). Dysbiosis of the gut microbiota is associated with neurological impairment in Traumatic brain injury (TBI) patients. Our previous study found that TBI results in a decrease in the abundance of Prevotella copri (P. copri). P. copri has been shown to have antioxidant effects in various diseases. Meanwhile, guanosine (GUO) is a metabolite of intestinal microbiota that can alleviate oxidative stress after TBI by activating the PI3K/Akt pathway. In this study, we investigated the effect of P. copri transplantation on TBI and its relationship with GUO-PI3K/Akt pathway.

METHODS

In this study, a controlled cortical impact (CCI) model was used to induce TBI in adult male C57BL/6J mice. Subsequently, P. copri was transplanted by intragastric gavage for 7 consecutive days. To investigate the effect of the GUO-PI3K/Akt pathway in P. copri transplantation therapy, guanosine (GUO) was administered 2 h after TBI for 7 consecutive days, and PI3K inhibitor (LY294002) was administered 30 min before TBI. Various techniques were used to assess the effects of these interventions, including quantitative PCR, neurological behavior tests, metabolite analysis, ELISA, Western blot analysis, immunofluorescence, Evans blue assays, transmission electron microscopy, FITC-dextran permeability assay, gastrointestinal transit assessment, and 16 S rDNA sequencing.

RESULTS

P. copri abundance was significantly reduced after TBI. P. copri transplantation alleviated motor and cognitive deficits tested by the NSS, Morris's water maze and open field test. P. copri transplantation attenuated oxidative stress and blood-brain barrier damage and reduced neuronal apoptosis after TBI. In addition, P. copri transplantation resulted in the reshaping of the intestinal flora, improved gastrointestinal motility and intestinal permeability. Metabolomics and ELISA analysis revealed a significant increase in GUO levels in feces, serum and injured brain after P. copri transplantation. Furthermore, the expression of p-PI3K and p-Akt was found to be increased after P. copri transplantation and GUO treatment. Notably, PI3K inhibitor LY294002 treatment attenuated the observed improvements.

CONCLUSIONS

We demonstrate for the first time that P. copri transplantation can improve GI functions and alter gut microbiota dysbiosis after TBI. Additionally, P. copri transplantation can ameliorate neurological deficits, possibly via the GUO-PI3K/Akt signaling pathway after TBI.

Orphan Nuclear Receptor NR4A3 Promotes Vascular Calcification via Histone Lactylation

BACKGROUND

Medial arterial calcification is a chronic systemic vascular disorder distinct from atherosclerosis and is commonly observed in patients with chronic kidney disease, diabetes, and aging individuals. We previously showed that NR4A3 (nuclear receptor subfamily 4 group A member 3), an orphan nuclear receptor, is a key regulator in apo (apolipoprotein) A-IV-induced atherosclerosis progression; however, its role in vascular calcification is poorly understood.

METHODS

We generated NR4A3-/- mice and 2 different types of medial arterial calcification models to investigate the biological roles of NR4A3 in vascular calcification. RNA-seq was performed to determine the transcriptional profile of NR4A3-/- vascular smooth muscle cells under β-glycerophosphate treatment. We integrated Cleavage Under Targets and Tagmentation analysis and RNA-seq data to further investigate the gene regulatory mechanisms of NR4A3 in arterial calcification and target genes regulated by histone lactylation.

RESULTS

NR4A3 expression was upregulated in calcified aortic tissues from chronic kidney disease mice, 1,25(OH)2VitD3 overload-induced mice, and human calcified aorta. NR4A3 deficiency preserved the vascular smooth muscle cell contractile phenotype, inhibited osteoblast differentiation-related gene expression, and reduced calcium deposition in the vasculature. Further, NR4A3 deficiency lowered the glycolytic rate and lactate production during the calcification process and decreased histone lactylation. Mechanistic studies further showed that NR4A3 enhanced glycolysis activity by directly binding to the promoter regions of the 2 glycolysis genes ALDOA and PFKL and driving their transcriptional initiation. Furthermore, histone lactylation promoted medial calcification both in vivo and in vitro. NR4A3 deficiency inhibited the transcription activation and expression of Phospho1 (phosphatase orphan 1). Consistently, pharmacological inhibition of Phospho1 attenuated calcium deposition in NR4A3-overexpressed vascular smooth muscle cells, whereas overexpression of Phospho1 reversed the anticalcific effect of NR4A3 deficiency in vascular smooth muscle cells.

CONCLUSIONS

Taken together, our findings reveal that NR4A3-mediated histone lactylation is a novel metabolome-epigenome signaling cascade mechanism that participates in the pathogenesis of medial arterial calcification.

Serum exosomes miR-206 and miR-549a-3p as potential biomarkers of traumatic brain injury

Traumatic brain injury (TBI) is one of the leading causes of death and disability worldwide. However, effective diagnostic, therapeutic and prognostic biomarkers are still lacking. Our research group previously revealed through high-throughput sequencing that the serum exosomes miR-133a-3p, miR-206, and miR-549a-3p differ significantly in severe TBI (sTBI), mild or moderate TBI (mTBI), and control groups. However, convincing experimental evidence is lacking. To solve this problem, we used qPCR in this study to further verify the expression levels of serum exosomes miR-133a-3p, miR-206 and miR-549a-3p in TBI patients. The results showed that the serum exosomes miR-206 and miR-549a-3p showed good predictive value as biomarkers of TBI. In addition, in order to further verify whether serum exosomes miR-206 and miR-549a-3p can be used as potential biomarkers in patients with TBI and to understand the mechanism of their possible effects, we further determined the contents of SOD, BDNF, VEGF, VEGI, NSE and S100β in the serum of TBI patients. The results showed that, serum exosomes miR-206 and miR-549a-3p showed good correlation with BDNF, NSE and S100β. In conclusion, serum exosomes miR-206 and miR-549a-3p have the potential to serve as potential biomarkers in patients with TBI.

FDA compound library screening Baicalin upregulates TREM2 for the treatment of cerebral ischemia-reperfusion injury

Acute ischemic stroke (AIS) is a leading cause of global incidence and mortality rates. Oxidative stress and inflammation are key factors in the pathogenesis of AIS neuroinjury. Therefore, it is necessary to develop drugs that target neuroinflammation and oxidative stress in AIS. The Triggering Receptor Expressed on Myeloid Cells 2 (TREM2), primarily expressed on microglial cell membranes, plays a critical role in reducing inflammation and oxidative stress in AIS. In this study, we employed a high-throughput screening (HTS) strategy to evaluate 2625 compounds from the (Food and Drug Administration) FDA library in vitro to identify compounds that upregulate the TREM2 receptor on microglia. Through this screening, we identified Baicalin as a potential drug for AIS treatment. Baicalin, a flavonoid compound extracted and isolated from the root of Scutellaria baicalensis, demonstrated promising results. Next, we established an in vivo mouse model of cerebral ischemia-reperfusion injury (MCAO/R) and an in vitro microglia cell of oxygen-glucose deprivation reperfusion (OGD/R) to investigate the role of Baicalin in inflammation injury, oxidative stress, and neuronal apoptosis. Our results showed that baicalin effectively inhibited microglia activation, reactive oxygen species (ROS) production, and inflammatory responses in vitro. Additionally, baicalin suppressed neuronal cell apoptosis. In the in vivo experiments, baicalin not only improved neurological functional deficits and reduced infarct volume but also inhibited microglia activation and inflammatory responses. Overall, our findings demonstrate the efficacy of Baicalin in treating MCAO/R by upregulating TREM2 to reduce inflammatory responses and inhibit neuronal apoptosis.

Human Glial Cells as Innovative Targets for the Therapy of Central Nervous System Pathologies

In vitro and preclinical in vivo research in the last 35 years has clearly highlighted the crucial physiopathological role of glial cells, namely astrocytes/microglia/oligodendrocytes and satellite glial cells/Schwann cells in the central and peripheral nervous system, respectively. Several possible pharmacological targets to various neurodegenerative disorders and painful conditions have therefore been successfully identified, including receptors and enzymes, and mediators of neuroinflammation. However, the translation of these promising data to a clinical setting is often hampered by both technical and biological difficulties, making it necessary to perform experiments on human cells and models of the various diseases. In this review we will, therefore, summarize the most relevant data on the contribution of glial cells to human pathologies and on their possible pharmacological modulation based on data obtained in post-mortem tissues and in iPSC-derived human brain cells and organoids. The possibility of an in vivo visualization of glia reaction to neuroinflammation in patients will be also discussed.

Deletion of Slc9a1 in Cx3cr1+ cells stimulated microglial subcluster CREB1 signaling and microglia-oligodendrocyte crosstalk

Microglial Na/H exchanger-1 (NHE1) protein, encoded by Slc9a1, plays a role in white matter demyelination of ischemic stroke brains. To explore underlying mechanisms, we conducted single cell RNA-seq transcriptome analysis in conditional Slc9a1 knockout (cKO) and wild-type (WT) mouse white matter tissues at 3 days post-stroke. Compared to WT, Nhe1 cKO brains expanded a microglial subgroup with elevated transcription of white matter myelination genes including Spp1, Lgals3, Gpnmb, and Fabp5. This subgroup also exhibited more acidic pHi and significantly upregulated CREB signaling detected by ingenuity pathway analysis and flow cytometry. Moreover, the Nhe1 cKO white matter tissues showed enrichment of a corresponding oligodendrocyte subgroup, with pro-phagocytosis and lactate shuffling gene expression, where activated CREB signaling is a likely upstream regulator. These findings demonstrate that attenuation of NHE1-mediated H+ extrusion acidifies microglia/macrophage and may underlie the stimulation of CREB1 signaling, giving rise to restorative microglia-oligodendrocyte interactions for remyelination.

TREM2 improves microglia function and synaptic development in autism spectrum disorders by regulating P38 MAPK signaling pathway

BACKGROUND

Autism spectrum disorder (ASD) encompasses a diverse range of neurodevelopmental disorders, but the precise underlying pathogenesis remains elusive. This study aim to explore the potential mechanism of TREM2 in regulating microglia function in ASD.

MATERIALS AND METHODS

The offspring rat model of ASD was established through prenatal exposure to valproic acid (VPA), and the behavioral symptoms of the ASD model were observed. On postnatal day (PND) 7 and PND 28, the effects of prenatally exposure to VPA on synaptic development and microglia phenotype of offspring rats were observed. Primary microglia were cultured in vitro. Lentivirus and adenovirus were utilized to interfere with TREM2 and overexpress TREM2.

RESULTS

Prenatally VPA exposure induced offspring rats to show typical ASD core symptoms, which led to abnormal expression of synapse-related proteins in the prefrontal cortex of offspring rats, changed the phenotype of microglia in offspring rats, promoted the polarization of microglia to pro-inflammatory type, and increased inflammatory response. The experimental results in vitro showed that overexpression of TREM2 could increase the expression of Gephyrin, decrease the content of CD86 protein and increase the content of CD206 protein. In addition, after the expression of TREM2 was interfered, the content of p-P38 MAPK protein increased and the content of p-ELK-1 protein decreased.

CONCLUSION

The protective influence of TREM2 on the VPA-induced ASD model is attributed to its inhibition of the P38 MAPK pathway, this protective effect may be achieved by promoting the polarization of microglia to anti-inflammatory phenotype and improving the neuronal synaptic development.

Innovative Insights into Traumatic Brain Injuries: Biomarkers and New Pharmacological Targets

A traumatic brain injury (TBI) is a major health issue affecting many people across the world, causing significant morbidity and mortality. TBIs often have long-lasting effects, disrupting daily life and functionality. They cause two types of damage to the brain: primary and secondary. Secondary damage is particularly critical as it involves complex processes unfolding after the initial injury. These processes can lead to cell damage and death in the brain. Understanding how these processes damage the brain is crucial for finding new treatments. This review examines a wide range of literature from 2021 to 2023, focusing on biomarkers and molecular mechanisms in TBIs to pinpoint therapeutic advancements. Baseline levels of biomarkers, including neurofilament light chain (NF-L), ubiquitin carboxy-terminal hydrolase-L1 (UCH-L1), Tau, and glial fibrillary acidic protein (GFAP) in TBI, have demonstrated prognostic value for cognitive outcomes, laying the groundwork for personalized treatment strategies. In terms of pharmacological progress, the most promising approaches currently target neuroinflammation, oxidative stress, and apoptotic mechanisms. Agents that can modulate these pathways offer the potential to reduce a TBI's impact and aid in neurological rehabilitation. Future research is poised to refine these therapeutic approaches, potentially revolutionizing TBI treatment.

Targeting pyroptosis with nanoparticles to alleviate neuroinflammatory for preventing secondary damage following traumatic brain injury

Posttraumatic neuroinflammation is a key driver of secondary injury after traumatic brain injury (TBI). Pyroptosis, a proinflammatory form of programmed cell death, considerably activates strong neuroinflammation and amplifies the inflammatory response by releasing inflammatory contents. Therefore, treatments targeting pyroptosis may have beneficial effects on the treatment of secondary brain damage after TBI. Here, a cysteine-alanine-glutamine-lysine peptide-modified β-lactoglobulin (β-LG) nanoparticle was constructed to deliver disulfiram (DSF), C-β-LG/DSF, to inhibit pyroptosis and decrease neuroinflammation, thereby preventing TBI-induced secondary injury. In the post-TBI mice model, C-β-LG/DSF selectively targets the injured brain, increases DSF accumulation, and extends the time of the systemic circulation of DSF. C-β-LG/DSF can alleviate brain edema and inflammatory response, inhibit secondary brain injury, promote learning, and improve memory recovery in mice after trauma. Therefore, this study likely provided a potential approach for reducing the secondary spread of TBI.

Promotion of neuroinflammation by the glymphatic system: a new insight into ethanol extracts from Alisma orientale in alleviating obesity-associated cognitive impairment

BACKGROUND

Obesity is one of the critical risk factors for cognitive dysfunction. The glymphatic system (GS) plays a key role in the pathogenesis of cognitive deficits. Alisma orientale has been shown to have anti-inflammatory and antihyperlipidemic effects, whereas its effects and underlying mechanisms on obesity-associated cognitive impairment (OACI) are unclear.

PURPOSE

This work aims to decipher the mechanism of ethanol extracts from Alisma orientale (EEAO) in restoring cognitive impairment in HFD-induced obese mice through a GS approach.

METHODS

The restoration of abnormal glucose/lipid metabolism and excess adipose deposition by EEAO were assayed by biochemical analysis and visually displayed by a micro-CT scanner and Oil Red O staining. Biochemical assays and Western blotting (WB) were used to measure cerebral blood flow (CBF), free fatty acid (FFAs) levels and the structural integrity of the blood-brain barrier (BBB). Microglial activation and neuroinflammation were assessed with immunohistochemistry staining, ELISA and WB. Moreover, GS function was determined by immunofluorescence staining, fluorescence tracer imaging and WB. Finally, the neuropathological features and cognitive functions were detested with immunohistochemistry staining, immunofluorescence and Morris Water Maze.

RESULTS

EEAO not only alleviated body weight, cerebral lipid accumulation and serum FFAs in HFD-induced obese mice, but also increased CBF and BBB integrity. EEAO suppressed microglial activation and lipid deposition in the hippocampus and reduced the level of inflammatory cytokines including IL-6, IL-1β and TNF-α in brain tissue. Interestingly, long-term HFD-induced GS dysfunction was significantly restored after EEAO intervention, and neuropathological lesions and cognitive deficits were also markedly rescued.

CONCLUSION

EEAO rescued the cognitive deficits of OACI by inhibiting neuroinflammation and restoring GS dysfunction, indicating a potential remedy for OACI.

Repurposing of pexidartinib for microglia depletion and renewal

Pexidartinib (PLX3397) is a small molecule receptor tyrosine kinase inhibitor of colony stimulating factor 1 receptor (CSF1R) with moderate selectivity over other members of the platelet derived growth factor receptor family. It is approved for treatment of tenosynovial giant cell tumors (TGCT). CSF1R is highly expressed by microglia, which are macrophages of the central nervous system (CNS) that defend the CNS against injury and pathogens and contribute to synapse development and plasticity. Challenged by pathogens, apoptotic cells, debris, or inflammatory molecules they adopt a responsive state to propagate the inflammation and eventually return to a homeostatic state. The phenotypic switch may fail, and disease-associated microglia contribute to the pathophysiology in neurodegenerative or neuropsychiatric diseases or long-lasting detrimental brain inflammation after brain, spinal cord or nerve injury or ischemia/hemorrhage. Microglia also contribute to the growth permissive tumor microenvironment of glioblastoma (GBM). In rodents, continuous treatment for 1-2 weeks via pexidartinib food pellets leads to a depletion of microglia and subsequent repopulation from the remaining fraction, which is aided by peripheral monocytes that search empty niches for engraftment. The putative therapeutic benefit of such microglia depletion or forced renewal has been assessed in almost any rodent model of CNS disease or injury or GBM with heterogeneous outcomes, but a tendency of partial beneficial effects. So far, microglia monitoring e.g. via positron emission imaging is not standard of care for patients receiving Pexidartinib (e.g. for TGCT), so that the depletion and repopulation efficiency in humans is still largely unknown. Considering the virtuous functions of microglia, continuous depletion is likely no therapeutic option but short-lasting transient partial depletion to stimulate microglia renewal or replace microglia in genetic disease in combination with e.g. stem cell transplantation or as part of a multimodal concept in treatment of glioblastoma appears feasible. The present review provides an overview of the preclinical evidence pro and contra microglia depletion as a therapeutic approach.

Hypoxia ischemia results in blood brain barrier damage via AKT/GSK-3β/CREB pathway in neonatal rats

Previous studies have showed that the permeability of blood brain barrier (BBB) increased after hypoxia ischemia (HI). The current research uncovered the mechanism of altered BBB permeability after hypoxic-ischemic brain damage (HIBD) through AKT/GSK-3β/CREB signaling pathway in neonatal rats. Firstly, Magnetic resonance imaging (MRI) combined with hematoxylin-eosin (H&E) staining was used to assess brain injury. Initial findings showed abnormal signals in T2-weighted imaging (T2WI) and diffusion weighted imaging (DWI). Changes also happened in the morphology of nerve cells. Subsequently, we found that BBB damage is manifested as leakage of immunoglobulin G (IgG) and destruction of BBB-related proteins and ultrastructure. Meanwhile, the levels of matrix metalloproteinase-9 (MMP-9) significantly increased at 24 h after HIBD compared to a series of time points. Additionally, immunohistochemical (IHC) staining combined with Western blot (WB) was used to verify the function of the AKT/GSK-3β/CREB signaling pathway in BBB damage after HI in neonatal rats. Results showed that less Claudin-5, ZO-1, p-AKT, p-GSK-3β and p-CREB, along with more MMP-9 protein expression were visible on the damaged side of the cerebral cortex in the HIBD group in contrast to the sham and HIBD + SC79 groups. Together, our findings demonstrated that HI in neonatal rats might upregulate the levels of MMP-9 protein and downregulate the levels of Claudin-5 and ZO-1 by inhibiting the AKT/GSK-3β/CREB pathway, thus disrupting the BBB, which in turn aggravates brain damage after HI in neonatal rats.