Post-stroke cognitive impairment (PSCI) is characterized by progressive cognitive decline following ischemic stroke, and recent studies have suggested that natural compounds may offer therapeutic benefits; however, the effects and mechanisms of Betulin in PSCI remain unclear. Male C57BL/6 mice were subjected to ischemic stroke surgery to induce PSCI and treated with Betulin (50 mg/kg/day) for 3 weeks, followed by assessments of cognitive impairment, pathological changes, and the production of pro-inflammatory cytokines. Network pharmacology and RNA sequencing were performed to explore potential mechanisms. In vitro, BV2 microglia were stimulated with lipopolysaccharide to examine the anti-inflammatory effects of Betulin. Betulin improved cognitive performance, reduced microglial activation, and attenuated neuroinflammation, as evidenced by decreased levels of TNF-α, IL-1β, and IL-6. Mechanistically, the epidermal growth factor receptor (EGFR)/JAK2/STAT3 pathway was identified as a key pathway potentially involved in these effects. Further experiments with EGFR point-mutation constructs indicated that disrupting the Betulin-EGFR interaction attenuated the inhibitory effect of Betulin on the EGFR/JAK2/STAT3 pathway. Collectively, these findings suggest that Betulin mitigates microglia-driven neuroinflammation by targeting EGFR and may represent a potential therapeutic candidate for PSCI.
BACKGROUND:The probiotic Lactobacillus mucosae has been widely shown to have many positive effects. However, its neuroprotective effects and underlying mechanism in Alzheimer's disease (AD) remain elusive. METHODS:Male APP/PS1 mice were treated for 4 weeks with L. mucosae WMU007, followed by the evaluation of cognitive function, neuronal damage, amyloid-β (Aβ) deposition, and Tau phosphorylation. RNA-seq coupled with Gene Ontology (GO) enrichment analysis implicated L. mucosae WMU007 in modulating oxidative stress in this AD model. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and qPCR were performed to identify the specific mechanism by which this probiotic suppresses oxidative stress in the pathogenesis of AD. In addition, we quantified the levels of classical oxidative stress markers, such as superoxide dismutase 2 (SOD2) and glutathione peroxidase 4 (GPX4). We also examined the expression of cannabinoid receptor type 2 (CB2) and its key downstream regulators in the redox pathway, namely nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1), in both animal and cellular models. RESULTS:Our results showed that treatment with L. mucosae WMU007 significantly decreased cognitive impairment, neuronal damage, Aβ deposits, and Tau phosphorylation in APP/PS1 mice. Activation of CB2 was identified as the key mechanism by which L. mucosae WMU007 reduces oxidative stress in AD. In addition, L. mucosae WMU007 reduced oxidative stress and increased the levels of CB2 pathway-related proteins in vivo and in vitro. CONCLUSIONS:These results indicate that L. mucosae WMU007 confers neuroprotection in AD by targeting CB2-mediated oxidative pathways, highlighting its therapeutic potential as a novel probiotic intervention.
BACKGROUND:Trimethylamine-N-oxide (TMAO), a metabolite produced by gut microbiota, has been linked to brain disease; however, its role in intracerebral hemorrhage (ICH) remains unclear. METHODS:Animal experiments were conducted to demonstrate the effects of TMAO on collagenase-induced rat models of ICH. Neurological function was evaluated using the modified neurological severity score (mNSS), and neuronal damage was assessed by NeuN staining. Microglial activation and pro-inflammatory cytokine expression were examined. To further investigate the mechanism of TMAO, we performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis on its predicted molecular targets. BV2 microglia were treated with TMAO to assess the levels of reactive oxygen species (ROS), cyclooxygenase-2 (COX-2), NOD-like receptor protein 3 (NLRP3), and caspase-1. Moreover, ICH rats were intragastrically treated with TMAO precursor L-carnitine (LC), and antibiotic cocktail treatment was used to deplete the gut microbiota, then assessed the effect. RESULTS:Our results showed that TMAO administration exacerbated neurological deficits and microglial-mediated neuroinflammation in ICH rats. NOD-like receptor signaling pathway was a key mechanism promoting ICH pathogenesis and confirmed that TMAO supplementation exacerbated microglial activation by regulating NLRP3 inflammasome activity in vitro. Moreover, gut microbiota depletion attenuated TMAO-induced activation of NLRP3 and the subsequent neuroinflammatory response in ICH. CONCLUSION:Collectively, these findings showed that Microbial Metabolite TMAO contributes to ICH-induced neuroinflammation by activating the NLRP3 signaling pathway.
Gut microbial metabolites abnormity links to Alzheimer’s disease (AD) progression, yet the mechanism remains unknown. Here, we observed a markedly decreased level of indole-3-acetic acid (IAA) in AD patients, and the IAA level was negatively correlated with cognitive impairment. IAA supplementation improved cognitive dysfunction and synaptic damage, and suppressed microglial activation and synaptic phagocytosis in AD mouse and cell models. RNA sequencing revealed an increase in phagocytosis-associated pathway activity and gene expression, and C-C chemokine receptor 4 (CCR4) was identified as a key regulator of this process. IAA could inhibit the expression level of CCR4, and siRNAs CCR4 markedly inhibited microglia-mediated phagocytosis of synapse. We further demonstrated that microglial CCR4 interacts with aryl hydrocarbon receptor (AHR), a key receptor of IAA, and proposed the hypothesis that AHR binds to the CCR4 promoter, thereby inhibiting its transcriptional activity. Moreover, we further revealed that bacteria producing IAA supplementation inhibited microglia-mediated synaptic loss by down-regulating CCR4, thus delaying Alzheimer’s progression. These findings elucidate the mechanisms underlying microbial metabolite IAA’s impact on AD, highlighting that targeting CCR4 inhibition in microglia-mediated synaptic phagocytosis represents a promising therapeutic strategy for AD.
Microglia-mediated neuroinflammation is a key driver of Alzheimer's disease (AD) progression, exacerbating neuronal damage and pathological changes. Pterostilbene (PTE), a natural anti-inflammatory stilbenoid, shows neuroprotective potential in AD, but its specific mechanism in regulating AD-related neuroinflammation remains unclear. Here, we explored the anti-neuroinflammatory effect and mechanisms of PTE against AD. APPswe/PS1dE9 (APP/PS1) transgenic mice were treated intragastrically with PTE for 4 weeks, followed by evaluation of cognitive function and pathological changes. Amyloid-β burden, Tau protein phosphorylation, microglial activation, and proinflammatory cytokines production were analyzed. To further investigate the potential mechanism of PTE, an integrated approach combining network pharmacology, RNA sequencing, molecular docking, molecular dynamics simulations, and cell transfection techniques were conducted. Our results showed that PTE treatment improved cognitive impairment, amyloid-β deposits, Tau protein phosphorylation, microglia activation, and production of tumor necrosis factor-α, interleukin-1β, and interleukin-6 in vivo and in vitro. Notably, molecular docking predicted that PTE has binding affinity for Janus kinase 2 (JAK2) at LYS-857, LYS-882, and LEU-932. Consistently, site-directed mutagenesis reduced the inhibitory effect of PTE on JAK2/signal transducer and activator of transcription 3 (STAT3) phosphorylation, supporting JAK2 as a functional target. Meanwhile, we revealed that PTE effectively inhibited activation of microglia in the APP/PS1 mice by regulating JAK2-STAT3 pathway. These findings indicate that PTE treatment could attenuate microglia-mediated neuroinflammation via regulating JAK2-STAT3 signaling pathway, which might provide a novel option to elucidate the effects of PTE on AD.
Recent evidence suggests that microglial activation, driven by a metabolic shift towards glycolysis, was involved in the pathogenesis of Alzheimer’s disease (AD). Although sphingolipid (SL) dysregulation has been linked to AD, the role of 1-deoxysphinganine (deoxySO), an atypical and neurotoxic SL, on microglial glycolytic reprogramming remains unclear. We measured serum deoxySO levels in AD patients and evaluated their association with cognitive performance. In APP/PS1 mice, we examined cerebral deoxySO level and the effects of deoxySO supplementation on cognitive function, neuropathology, and microglial activation. In vitro, BV2 microglia were used to assess inflammatory and metabolic changes via qPCR, western blot, ELISA, and RNA-seq analyses. The serum deoxySO levels were significantly elevated in AD patients, which was positively correlated with cognitive impairment. APP/PS1 mice exhibited increased cerebral deoxySO level, and supplementation with deoxySO could exacerbate cognitive deficits and Aβ plaque accumulation. Moreover, deoxySO supplementation increased microglial activation and enhanced inflammation in vivo and in vitro AD models. qPCR analysis identified disease-associated microglia (DAM) as a key deoxySO-responsive subpopulation, while RNA-seq revealed significant enrichment of genes related to glycolytic metabolism and inflammatory responses. Subsequently, qPCR confirmed that deoxySO promoted glycolytic metabolic reprogramming, which promoted DAM activation, thereby aggravating AD pathology. These findings identify deoxySO as a critical metabolic driver that links to microglial glycolytic activation and neuroinflammation, suggesting that targeting deoxySO-mediated metabolic pathways may offer a novel therapeutic strategy for AD.
Emerging evidence suggests that probiotics may have a significant impact on the regulation of mitochondrial oxidative stress in Alzheimer’s disease (AD). However, the research focusing on the specific bacteria responsible for mitochondrial oxidative stress of AD remains limited. This study explores the impact and underlying mechanisms of probiotic W. confusa WMU005 on mitochondrial oxidative stress in AD. The probiotic W. confusa WMU005 was isolated from the healthy people. APP/PS1 mice were administered live W. confusa WMU005 for 4 weeks and then subjected to cognitive test. Aβ deposition, Tau phosphorylation, neuronal apoptosis, oxidative stress, and mitochondrial damage of brain were measured. Additionally, APP/SWE cells treated with W. confusa WMU005 fermentation broth showed altered levels of silent information regulator 1 (SIRT1) and proliferator-activated receptor γ coactivator 1α (PGC-1α). Meanwhile, we confirmed that W. confusa WMU005 could regulate SIRT1 pathway in APP/PS1 mice. Our results revealed that W. confusa WMU005 improved cognitive function, reduced Aβ and Tau pathology. Furthermore, W. confusa WMU005 treatment exerted antioxidative effects by activating the SIRT1 pathway. We further demonstrated that W. confusa WMU005 mitigated the mitochondrial oxidative stress via activating SIRT1 pathway in vitro. Meanwhile, we revealed that W. confusa WMU005 effectively inhibited the mitochondrial oxidative stress in the APP/PS1 mice by regulating SIRT1 pathway. These findings suggest that W. confusa WMU005 exerts protective effects on AD through the involvement of the SIRT1 signaling pathway, which opened avenues for novel therapeutic strategies towards treating AD.
Neurocysticercosis is a common parasitic disease of the central nervous system (CNS), and its clinical manifestation depends on the number and location of the lesions and the host’s immune response to parasites. Here, we reported a case study of a 34-year-old male patient who presented with 5 times repeated incidents of transient upper left limb weaknesses, each time lasting for about one minute a day. Cranial magnetic resonance imaging (MRI) revealed long T1- and long T2-weighted signals indicating lesions in the right insular and temporal lobes, stenosis of the right lateral fissure, and irregular annularly enhanced lesions in the right lateral fissure. Furthermore, magnetic resonance angiography (MRA) examinations revealed the occurrence of local stenosis in the M2 segment of the right middle cerebral artery. The patient was diagnosed with cerebral neurocysticercosis. After albendazole treatment, the annular ring enhancement of the lesion was significantly reduced, and the local stenosis of the middle cerebral artery disappeared, as well.
Ethnopharmacological relevance Increasing evidence suggests that ferroptosis, an iron-dependent form of cell death characterized by lipid peroxidation, may play a substantial role in the traumatic brain injury (TBI) pathophysiology. 3-n-butylphthalide (NBP), a compound extracted from the seeds of Apium graveolens Linn (Chinese celery) and used in China to treat ischemic stroke, has demonstrated encouraging anti-reactive oxygen species (ROS) effects. Ascertaining whether NBP can inhibit ferroptosis and its mechanism could potentially expand its use in models of neurological injury and neurodegenerative diseases. Methods and Results In this study, we used erastin-induced in vitro ferroptosis models (HT22 cells, hippocampal slices, and primary neurons) and an in vivo controlled cortical impact mouse model. Our study revealed that NBP administration mitigated erastin-induced death in HT-22 cells and decreased ROS levels, lipid peroxidation, and mitochondrial superoxide indicators, resulting in mitochondrial protection. Moreover, the ability of NBP to inhibit ferroptosis was confirmed in organotypic hippocampal slice cultures and a TBI mouse model. NBP rescued neurons, inhibited microglial activation, and reduced iron levels in the brain tissue. The protective effect of NBP can be partly attributed to the inhibition of the AHR-CYP1B1 axis, as evidenced by RNA-seq and CYP1B1 overexpression/inhibition experiments in HT22 cells and primary neurons. Conclusions Our study underscores that NBP inhibition of the AHR-CYP1B1 axis reduces ferroptosis in neuronal damage and ameliorates brain injury.
An increasing number of studies have shown that commensal gut microbes may be involved in the pathogenesis of Alzheimer's disease (AD). The influence of gut microbe-derived metabolites, such as trimethylamine N-oxide (TMAO), has attracted a lot of attention. However, the influence and pathways mediated by gut microbe-derived metabolites in the pathogenesis of AD remain uncertain. Here, we observed a significant increase in the abundance of Blautia coccoides in AD patients, which showed positive predictive value for serum p-Tau181 levels. Supplementation with B. coccoides could exacerbate cognitive impairment and Tau phosphorylation in P301s mice. We identified TMAO as a key B. coccoides-derived metabolite promoting Tau phosphorylation by functional gene analysis, metabolomic analysis and VIP analysis, and further demonstrated that it was able to promote oxidative stress of AD in vitro. Mechanistically, TMAO could bind to hypoxia-inducible factor 1 alpha (HIF1α) at 235-238 sites, which promoted oxidative stress through the inhibition of HIF1α signal, thereby aggravating AD pathology. This study elucidated the important role of B. coccoides-derived metabolite TMAO in exacerbating AD and provided new insights for gut microbe/metabolite-based therapeutic strategies.
Gut microbiota plays a crucial role in the pathogenesis of Alzheimer disease (AD). Here, we found that AD patients had significantly lower abundance of Agathobacter, which were negatively correlated with cognitive impairment. Animal experiments showed that Agathobacter rectalis (A. rectalis) supplementation increased beneficial commensal bacteria, significantly improved pathological damage, and suppressed microglial activation in APP/PS1 mice. We further demonstrated that butyric acid, a metabolite of A. rectalis, reduced microglial activation and pro-inflammatory factor production via Akt/ nuclear factor κB (NF-κB) signal pathway in vitro. Meanwhile, we revealed that A. rectalis effectively inhibited activation of microglia in the APP/PS1 mice by regulating Akt/ NF-κB pathway. This finding highlights the role of A. rectalis and its metabolite butyrate in mitigating neuroinflammation in AD by modulating the Akt/NF-κB pathway.
Hyperuricemia is considered as an independent risk factor for acute ischemic stroke (AIS), and some AIS patients are accompanied by an increase in serum uric acid. Recent studies have highlighted the important role of gut microbiota in both hyperuricemia and AIS, but there is little available data on the relationship between gut microbiota and the pathogenesis of AIS with hyperuricemia (HAS). Here we profiled the gut microbiota composition in 63 HAS patients and 269 non-HAS patients through 16s rRNA sequencing. Male rat with hyperuricemia were subjected to middle cerebral artery occlusion (MCAO) to establish HAS model and were then treated with Parabacteroides distasonis. Subsequently, the neurological deficit, pathological damages and blood-brain barrier disruption were evaluated. Moreover, the levels of ROS, inflammatory cytokines, NF-𝜿B pathway related protein, and vascular density markers were determined. There were significant differences of gut microbiota composition between HAS patients and non-HAS patients, and a significant decrease in the abundance of Parabacteroides in HAS patients compared to non-HAS patients. Animal experiments showed that supplementation with P. distasonis increased beneficial commensal bacteria, significantly improved neurological deficits, pathological damages and BBB disruption, as well as reduced the level of serum uric acid in HAS rats. We further demonstrated that P. distasonis treatment decreased ROS level and increased SOD2 level, thereby reducing oxidative stress. Meanwhile, P. distasonis effectively inhibited NF-𝜿B signal pathway and reduced the production of inflammatory cytokines, including TNF-α and IL-1β, alleviating the inflammatory response. Notably, P. distasonis treatment increased the levels of vascular density markers including cluster of differentiation 31 (CD31) and alpha-smooth muscle actin (α-SMA), ameliorating vascular damage in HAS rats. Together, these findings highlighted the important role of P. distasonis in the pathogenesis of HAS, and its mechanism was involved in the regulation of gut microbiota-gut-brain axis, which implied a novel strategy against HAS.
Driven by the scarcity of effective treatment options in clinical settings, the present study aimed to identify a new potential target for Alzheimer's disease (AD) treatment. We focused on Lars2, an enzyme synthesizing mitochondrial leucyl-tRNA, and its role in maintaining mitochondrial function. Bioinformatics analysis of human brain transcriptome data revealed downregulation of Lars2 in AD patients compared to healthy controls. During in vitro experiments, the knockdown of Lars2 in mouse neuroblastoma cells (neuro-2a cells) and primary cortical neurons led to morphological changes and decreased density in mouse hippocampal neurons. To explore the underlying mechanisms, we investigated how downregulated Lars2 expression could impede the phosphatidylinositol 3-kinase/protein kinase B (PI3K-AKT) pathway, thereby mitigating AKT's inhibitory effect on glycogen synthase kinase 3 beta (GSK3β). This led to the activation of GSK3β, causing excessive phosphorylation of Tau protein and subsequent neuronal degeneration. During in vivo experiments, knockout of lars2 in hippocampal neurons confirmed cognitive impairment through the Barnes maze test, the novel object recognition test, and nest-building experiments. Additionally, immunofluorescence assays indicated an increase in p-tau, atrophy in the hippocampal region, and a decrease in neurons following Lars2 knockout. Taken together, our findings indicate that Lars2 represents a promising therapeutic target for AD.
Parkinson's disease (PD) is intricately linked to abnormal gut microbiota, yet the specific microbiota influencing clinical outcomes remain poorly understood. Our study identified a deficiency in the microbiota genus Blautia and a reduction in fecal short-chain fatty acid (SCFA) butyrate level in PD patients compared to healthy controls. The abundance of Blautia correlated with the clinical severity of PD. Supplementation with butyrate-producing bacterium B. producta demonstrated neuroprotective effects, attenuating neuroinflammation and dopaminergic neuronal death in mice, consequently ameliorating motor dysfunction. A pivotal inflammatory signaling pathway, the RAS-related pathway, modulated by butyrate, emerged as a key mechanism inhibiting microglial activation in PD. The change of RAS-NF-κB pathway in PD patients was observed. Furthermore, B. producta-derived butyrate demonstrated the inhibition of microglial activation in PD through regulation of the RAS-NF-κB pathway. These findings elucidate the causal relationship between specific gut microbiota and PD, presenting a novel microbiota-based treatment perspective for PD.
Pyroptosis is considered one of a critical factor in the recovery of neurological function following traumatic brain injury. Brain injury activates a molecular signaling cascade associated with pyroptosis and inflammation, including NLRP3, inflammatory cytokines, caspase-1, gasdermin D (GSDMD), and other pyroptosis-related proteins. In this study, we explored the neuroprotective effects of LDC7559, a GSDMD inhibitor. Briefly, LDC7559, siRNA-GSDMD (si-GSDMD), or equal solvent was administrated to mice with a lipopolysaccharide + nigericin (LPS + Nig) model in vitro or with controlled cortical impact brain injury. The findings revealed that inflammation and pyroptosis levels were decreased by LDC7559 or si-GSDMD treatment both in vitro and in vivo. Immunofluorescence staining, brain water content, hematoxylin and eosin staining, and behavioral investigations suggested that LDC7559 or si-GSDMD inhibited microglial proliferation, ameliorated cerebral edema, reduced brain tissue loss, and promoted brain function recovery. Taken together, LDC7559 may inhibit pyroptosis and reduce inflammation by inhibiting GSDMD, thereby promoting the recovery of neurological function.
Thrombus is an extremely dangerous factor in the human body that can block the blood vessel. Once thrombosis happens in venous of lower limbs, local blood flow is impeded. This leads to venous thromboembolism (VTE) and even pulmonary embolism. In recent years, venous thromboembolism has frequently occurred in a variety of people, and there is no effective treatment for patients with different venous structures. For the patients with venous isomer with single valve structure, we establish a coupled computational model to simulate the process of thrombolysis with multi-dose treatment schemes by considering the blood as non-Newtonian fluid. Then, the corresponding in vitro experimental platform is built to verify the performance of the developed mathematical model. At last, the effects of different fluid models, valve structures and drug doses on thrombolysis are comprehensively studied through numerical and experimental observations. Comparing with the experimental results, the relative error of blood boosting index (BBI) obtained from non-Newtonian fluid model is 11% smaller than Newtonian fluid. In addition, the BBI from venous isomer is 1300% times stronger than patient with normal venous valve while the valve displacement is 500% times smaller. As consequence, low eddy current and strong molecular diffusion near the thrombus in case of isomer promote thrombolysis rate up to 18%. Furthermore, the 80 μM dosage of thrombolytic drugs gets the maximum thrombus dissolution rate 18% while the scheme of 50 μM doses obtains a thrombolysis rate of 14% in case of venous isomer. Under the two administration schemes for isomer patients, the rates from experiments are around 19.1% and 14.9%, respectively. It suggests that the proposed computational model and the designed experiment platform can potentially help different patients with venous thromboembolism to carry out clinical medication prediction.
Type 2 diabetes mellitus (T2DM) is a prevalent risk factor for cognitive impairment. Aerobic exercise can improve T2DM-related cognitive impairment; however, the possible mechanisms remain elusive. Thus, we assessed db/m mice and leptin receptor-deficient (db/db) mice that did or did not perform aerobic exercise (8 m/min, 60 min/day, and 5 days/week for 12 weeks). In this study, cognitive function was significantly impaired in the T2DM mice; aerobic exercise improved cognitive impairment through activating the AMPK/SIRT1 signalling pathway and inhibiting the JAK2/STAT3 signalling pathway in T2DM mice. However, after the application of RO8191 (JAK2 activator) or Compound C (AMPK inhibitor), the positive improvement of the exercise was evidently suppressed. Taken together, our data indicated that long-term aerobic exercise improves type 2 diabetes mellitus-related cognitive impairment by inhibiting JAK2/STAT3 and enhancing AMPK/SIRT1 pathways in mice.
Canagliflozin is an antidiabetic medicine that inhibits sodium-glucose cotransporter 2 (SGLT2) in proximal tubules. Recently, it was reported to have several noncanonical effects other than SGLT2 inhibiting. However, the effects of canagliflozin on skeletal muscle regeneration remain largely unexplored. Thus, in vivo muscle contractile properties recovery in mice ischemic lower limbs following gliflozins treatment was evaluated. The C2C12 myoblast differentiation after gliflozins treatment was also assessed in vitro. As a result, both in vivo and in vitro data indicate that canagliflozin impairs intrinsic myogenic regeneration, thus hindering ischemic limb muscle contractile properties, fatigue resistance recovery, and tissue regeneration. Mitochondrial structure and activity are both disrupted by canagliflozin in myoblasts. Single-cell RNA sequencing of ischemic tibialis anterior reveals a decrease in leucyl-tRNA synthetase 2 (LARS2) in muscle stem cells attributable to canagliflozin. Further investigation explicates the noncanonical function of LARS2, which plays pivotal roles in regulating myoblast differentiation and muscle regeneration by affecting mitochondrial structure and activity. Enhanced expression of LARS2 restores the differentiation of canagliflozin-treated myoblasts, and accelerates ischemic skeletal muscle regeneration in canagliflozin-treated mice. Our data suggest that canagliflozin directly impairs ischemic skeletal muscle recovery in mice by downregulating LARS2 expression in muscle stem cells, and that LARS2 may be a promising therapeutic target for injured skeletal muscle regeneration.