Neuroinflammation induced by lipopolysaccharide causes cognitive impairment in mice

Nuclear factor erythroid 2-related factor improves depression and cognitive dysfunction in rats with ischemic stroke by mediating wolfram syndrome 1

OBJECTIVE

This research aims to investigate the molecular mechanism of nuclear factor erythroid 2-related factor (Nrf2) in improving post-stroke depression and cognitive impairment (PSDCI) by mediating wolfram syndrome 1 (Wfs1).

METHODS

PSDCI rat model was established through middle cerebral artery occlusion (MCAO) and chronic unpredictable mild stress (CUMS). Dimethyl fumarate (DMF) was utilized as an Nrf2 activator, while Wfs1 knockdown lentiviral plasmid was injected into rats for functional investigations. Cognitive function- and depression-relevant parameters were assessed using Morris water maze, forced swimming, sucrose preference, modified neurological severity score (mNSS) tests. The infarct size, pathological changes, and neuronal damage were also evaluated. Additionally, oxidative stress- and inflammatory response-associated proteins were detected by enzyme-linked immunosorbent assay. The binding relation between Nrf2 and the Wfs1 promoter region was analyzed and verified by dual-luciferase and chromatin immunoprecipitation assays.

RESULTS

PSDCI rats had reduced Nrf2 and Wfs1 expression in the hippocampal tissue and inhibited nuclear translocation of Nrf2, showing aggravated oxidative stress and inflammatory responses as well as cognitive dysfunction- and depressive-like symptoms. However, these symptoms in PSDCI rats can be alleviated in response to Nrf2 activation. Furthermore, Nrf2 activation increased the enrichment level of Nrf2 in the Wfs1 promoter region, promoting the transcriptional expression of Wfs1. Wfs1 knockdown partly reversed the effect of Nrf2 activation on the neuronal damage, cognitive dysfunction- and depressive-like symptoms of PSDCI rats.

CONCLUSION

Nrf2 activation can promote Wfs1 expression to reduce neuroinflammation and oxidative stress responses, ultimately alleviating PSDCI in rats.

Efficacy of the neurotensin receptor 1 analog PD149163 in modulation of the kidney inflammation: Inhibition of the nuclear factor kappa β signaling pathway and oxidative stress in endotoxemic mice

This study elucidated that the neurotensin receptor 1 agonist PD149163 ameliorated the kidney inflammation in endotoxemic mice inhibiting the nuclear factor kappa β (NF-kβ) pathway and reducing the oxidative stress in a dose-dependent manner. Swiss albino female mice (8 weeks; 25 ± 5 gms) were maintained in six groups (n = 6): Group 1/control, Group 2, Group 3 and Group 4 were exposed to lipopolysaccharide/LPS (1 mg/kg bw; i.p; 5 days) followed by PD149163 treatment with low dose/NTS50 (50 μg/kg BW i.p. 28 days) and high dose/NTS100 (100 μg/kg BW i.p. 28 days) to Group 3 and Group 4 respectively. Group 5 and Group 6 mice were only treated with the agonist, similar low and high doses respectively for the same duration. The results showed LPS-induced significant increase in the plasma levels of the NF-kβ, pro-inflammatory cytokines (TNF-α, IL-6) and a decrease in the anti-inflammatory cytokine IL-10. A significant increase in the pro-oxidant (LPx) and decrease of the anti-oxidants (SOD, CAT) in the kidney tissue was noted. Plasma NTS level was significantly decreased along with a significant increase of the corticosterone. The inflammation was reflected in the kidney histopathology. PD149163 significantly reduced inflammation by down-regulating NF-kβ, TNF-α, IL-6, CORT levels, oxidative stress and alleviated kidney injury. PD149163 enhanced the plasma level of NT. The role of PD149163 in the modulation of inflammation of kidney tissue by its anti-inflammatory and anti-oxidative effects is suggested. Further studies may better confirm the efficacy of the NTS analog for therapeutic intervention in inflammation-related diseases of the kidney.

Minocycline attenuates TLR-4, NF-kB, TNF-α and COX-2 protein expression after lipopolysaccharide-induced neuroinflammation in the rat medial prefrontal cortex (mPFC)

Minocycline has been shown to ameliorate neuroinflammation that was encountered in many neurodegenerative diseases. This study aims to investigate the expression of inflammatory mediators in the rat medial prefrontal cortex (mPFC) after minocycline treatment in a lipopolysaccharide (LPS)- induced neuroinflammation rat model. Adult male Sprague Dawley (SD) rats (N = 50) were divided into 5 groups: (1) control, (2) LPS (5 mg/kg), (3) LPS + minocycline (25 mg/kg), (4) LPS + minocycline (50 mg/kg) and (5) LPS + memantine (10 mg/kg). Intraperitoneal minocycline and memantine were given daily for 14 days, while LPS injection was given once on the 5th day. Western blot and immunohistochemistry were used to assess density and expression of toll-like receptor-4 (TLR-4), nuclear factor kappa-B (NF-kB), tumor necrosis factor (TNF)-α and cyclooxygenase (COX)-2 in the medial prefrontal cortex (mPFC) of rats. Findings displayed that minocycline significantly decreased expression and density of TLR-4, NF-kB, TNF-α and COX-2 proteins that were comparable to memantine in mPFC of SD rat injected with single intraperitoneal LPS. Interestingly, the anti-inflammatory effects of minocycline 50 mg/kg were significantly more than minocycline 25 mg/kg. This study suggested that minocycline can modulate LPS-induced neuroinflammation in dose-dependent manner in the mPFC area. Thus, it is suggested that minocycline can be used as potential preventive-therapeutic drug for neuroinflammatory diseases such as depression and anxiety.

Blockage of CCL3 with neutralizing antibody reduces neuroinflammation and reverses Alzheimer disease phenotypes

BACKGROUND

Accumulating evidence indicates that neuroinflammation is involved in the pathogenesis of Alzheimer's disease (AD). According to RNA sequencing and quantitative PCR (qPCR), we found that chemokine CCL3 mRNA expression was abnormally upregulated in the brains of AD transgenic mice. Moreover, the levels of CCL3 in the serum of AD patients were significantly elevated and negatively correlated with their cognitive abilities. However, the role of CCL3 in AD neuroinflammation and pathological damages remains elusive.

METHODS

Using behavioral, histological, and biochemical methods, outcomes of CCL3 antibody treatment on neuropathology and cognitive deficits were studied in the APPswe/PS1dE9 mice.

RESULTS

In the present study, we reported that CCL3 protein expression was increased in the APPswe/PS1dE9 mice, whereas blockage of CCL3 with neutralizing antibody potently inhibited CCL3 activation in the APPswe/PS1dE9 mice down to the levels of wild-type mice. Specifically, CCL3 antibody significantly improved the learning and memory abilities of APPswe/PS1dE9 mice. In addition, CCL3 antibody treatment decreased cerebral amyloid-β (Aβ) levels and plaque burden via inhibiting amyloid precursor protein (APP) processing by reducing beta-site APP cleaving enzyme 1 (BACE1) expression in the APPswe/PS1dE9 mice. We also found that CCL3 antibody treatment alleviated neuroinflammation and reduced synaptic defects in the APPswe/PS1dE9 mice. Furthermore, the activated NF-κB signaling pathway in APPswe/PS1dE9 mice was inhibited by CCL3 antibody treatment.

CONCLUSIONS

Collectively, our findings provide evidence that CCL3 activation may contribute to the AD pathogenesis and may serve as a novel therapeutic target in the treatment of AD.

Unraveling lipopolysaccharide-induced behavioral and molecular effects in Lymnaea stagnalis, an emerging model organism for translational neuroscience

In this study, we employed a reductionist (yet not simplistic) approach utilizing the established invertebrate model system of the pond snail, Lymnaea stagnalis, to investigate the behavioral and molecular effects of systemic administration of lipopolysaccharide (LPS)-a bacterial endotoxin-on the snails' central ring ganglia. Snails received injections of either a low dose (2.5 μg) or a high dose (25 μg) of LPS, and their behavioral and molecular responses were assessed at 2, 6, and 24 h post-injection. With the high dose, snails exhibited a significant increase in homeostatic aerial respiration lasting for at least 24 h, consistent with a sickness-like state induced by the immune challenge. Additionally, we found that when administered 2, 6, or 24 h before operant conditioning training, the high dose of LPS, impaired memory formation. To further explore the underlying molecular mechanisms, we examined the transcriptional effects of the two doses of LPS in the snails' central ring ganglia. Our analysis showed a dose- and time-dependent upregulation of immune and stress-related genes, including key enzymes involved in the kynurenine pathway (KP), toll-like receptor 4 (TLR4), and heat shock protein 70 (HSP70). Metabolomic analysis suggested that the high LPS dose shifted KP metabolism toward the production of neurotoxic metabolites within the ganglia, indicating a LPS-induced neuroinflammatory state. Together, our findings provide valuable insight into the conserved mechanisms of neuroinflammation in this invertebrate model, offering a simplified yet effective tool to further explore the molecular interactions between the immune and central nervous systems.

Microbiome Gut-Brain-Axis: Impact on Brain Development and Mental Health

The current discovery that the gut microbiome, which contains roughly 100 trillion microbes, affects health and disease has catalyzed a boom in multidisciplinary research efforts focused on understanding this relationship. Also, it is commonly demonstrated that the gut and the CNS are closely related in a bidirectional pathway. A balanced gut microbiome is essential for regular brain activities and emotional responses. On the other hand, the CNS regulates the majority of GI physiology. Any disruption in this bidirectional pathway led to a progression of health problems in both directions, neurological and gastrointestinal diseases. In this review, we hope to shed light on the complicated connections of the microbiome-gut-brain axis and the critical roles of gut microbiome in the early development of the brain in order to get a deeper knowledge of microbiome-mediated pathological conditions and management options through rebalancing of gut microbiome.

Urolithin-A Derivative UAS03 Improves Cognitive Deficits and Memory by Activating Nrf2 Pathways to Alleviate Oxidative Stress and Neuroinflammation

Neuroinflammation is a key factor in age-related cognitive decline and memory impairment. UAS03, a potent synthetic analogue of Urolithin-A, has demonstrated anti-inflammatory and antioxidant properties. This investigation examined the neuroprotective effect of UAS03 on lipopolysaccharide (LPS) induced neuroinflammation, and its associated cognitive impairments, memory deficits, and depression-like behaviors. Intracerebroventricular administration of LPS (12 μg/kg) was performed to induce neuroinflammation in mice, followed by a 7 day treatment with UAS03 at 10 and 30 mg/kg doses. Mice were evaluated for depressive and anxiety-like behavior, spatial memory, and learning functions using a series of neurobehavioral test paradigms. Histopathological and molecular analyses were conducted using hematoxylin-eosin and cresyl violet staining, immunohistochemistry, ELISA, and Western blotting techniques. We have found that, UAS03 significantly enhanced cognitive and memory functions impaired by LPS while concurrently reducing depressive symptoms. Furthermore, the compound attenuated neuronal damage and decreased the expression of IBA-1 and GFAP in hippocampal region. Through the activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway, UAS03 effectively mitigated markers of oxidative stress and reduced levels of pro-inflammatory factors, including IL-1β, TNF-α, and COX-2. Cumulatively, this study provides compelling evidence that UAS03 exerts neuroprotective effects by regulating essential pathways involved in anti-inflammatory and neuroprotective mechanisms, suggesting its potential as a preventative measure against age-related cognitive decline and memory impairments associated with neuroinflammation.

Reactive Oxygen Species as a Common Pathological Link Between Alcohol Use Disorder and Alzheimer's Disease with Therapeutic Implications

Chronic alcohol consumption leads to excessive production of reactive oxygen species (ROS), driving oxidative stress that contributes to both alcohol use disorder (AUD) and Alzheimer's disease (AD). This review explores how ROS-mediated mitochondrial dysfunction and neuroinflammation serve as shared pathological mechanisms linking these conditions. We highlight the role of alcohol-induced oxidative damage in exacerbating neurodegeneration and compare ROS-related pathways in AUD and AD. Finally, we discuss emerging therapeutic strategies, including mitochondrial antioxidants and inflammasome inhibitors, that target oxidative stress to mitigate neurodegeneration. Understanding these overlapping mechanisms may provide new insights for preventing and treating ROS-driven neurodegenerative disorders.

A Mediterranean-style diet protects against cognitive and behavioral deficits, adiposity, and Alzheimer's disease-related markers, compared to a macronutrient-matched typical American diet in C57BL/6J mice

BackgroundResearch suggests that modifying risk factors may prevent or delay up to 40% of dementia cases, including Alzheimer's disease (AD). Thus, understanding the potential of healthful dietary patterns, like the Mediterranean diet (MD), in AD prevention is crucial. While supplementation of individual Mediterranean foods has demonstrated efficacy in reducing AD biomarkers and cognitive impairment in rodents, the effects of a comprehensive MD warrant further investigation. Additionally, while rodent studies often use a "Western diet" as a model for the typical American diet (TAD), these diets generally exceed the macronutrient densities of typical American consumption, particularly in fats and carbohydrates.ObjectiveTo better reflect human diets, we developed two diets for mice that more closely mirrored the macronutrient composition of the traditional MD or the TAD, each with matched macronutrient profiles (50% kcal from carbohydrates, 35% kcal from fat, 15% kcal from protein), and distinct food sources from Mediterranean regions or the U.S., respectively.MethodsMale C57BL/6J mice were randomly assigned to one diet (MD or TAD) at weaning (21 days of age), which they consumed for six months.ResultsCompared to the TAD, MD animals had lower body weight, abdominal and hepatic fat, serum TNF-α, and central Aβ1-42, while also exhibiting enhanced exploratory behavior, reduced anxiety-like behavior, and preserved spatial memory. The MD also protected against LPS-induced central inflammation and BDNF loss.ConclusionsThese findings suggest that a comprehensive MD provides protection against metabolic and AD-related markers in wildtype mice, despite matched caloric availability to the TAD.

Microglial activation and neuroinflammation in acute and chronic cognitive deficits in sepsis

Sepsis is characterised by dysregulated immune responses to infection, leading to multi-organ dysfunction and high rates of mortality. With increasing survival rates in recent years long-term neurological and psychiatric consequences have become more apparent in survivors. Many patients develop sepsis associated encephalopathy (SAE) which encompasses the profound but usually transient neuropsychiatric syndrome delirium but also new brain injury that emerges in the months and years post-sepsis. It is now clear that systemic inflammatory signals reach the brain during sepsis and that very significant neuroinflammation ensues. The major brain resident immune cell population, the microglia, has been implicated in acute and chronic cognitive dysfunction in animal models of sepsis based on a growing number of studies using bacterial endotoxin and in polymicrobial sepsis models such as cecal ligation and puncture. The current review explores the effects of sepsis on the brain, focussing on how systemic insults translate to microglial activation and neuroinflammation and how this disrupts neuronal function and integrity. We examine what has been demonstrated specifically with respect to microglial activation, revealing robust evidence for a role for neuroinflammation in sepsis-induced brain sequelae but less clear information on the extent of the specific microglial contribution to this, arising from findings using global knockout mice, non-selective drugs and treatments that equally target peripheral and central compartments. There is, nonetheless, clear evidence that microglia do become activated and do contribute to brain consequences of sepsis thus arguing for improved understanding of these neuroinflammatory processes toward the prevention and treatment of sepsis-induced brain dysfunction.

A Chloroform Fraction Derived from Vitis vinifera Root Ethanol Extract Attenuates Lipopolysaccharide-Induced Inflammatory Responses and Cognitive Dysfunction in BV-2 Microglia Cells and C57BL/6J Mouse Model

This study aimed to investigate the inhibitory effect of the chloroform fraction (CF) from Vitis vinifera root extract on LPS-induced neuroinflammation in BV-2 microglia cells and a C57/BL6J mouse model. CF significantly suppressed LPS-induced proinflammatory cytokines, including nitric oxide (NO), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in BV-2 microglia cells. Mechanistically, CF inhibited LPS-induced activation of nuclear factor-κB (NF-κB) by blocking the p65 subunit and preventing the phosphorylation of NF-kappa-B inhibitor α (IκBα), while its effect was independent of the mitogen-activated protein kinase (MAPK) pathway. Furthermore, CF modulated the TRIF signaling pathway by regulating TANK-binding kinase 1 (TBK1) and interferon regulatory factor 3 (IRF3), which contributed to the suppression of inflammatory mediators in BV-2 microglia cells. In vivo, we evaluated the neuroprotective effects of CF against cognitive dysfunction and inflammatory responses in an LPS-induced mouse model. Our behavioral assessments, including the Morris water maze and Y-maze tests, demonstrated that CF alleviated LPS-induced spatial learning impairment and cognitive decline. Additionally, CF significantly reduced the levels of inflammatory cytokines in serum and inflammatory mediators proteins expression in whole brain in LPS-injected mice, suggesting a direct link between reduced inflammatory responses and improved cognitive function. These findings suggest that CF from V. vinifera root extract may serve as a potential therapeutic strategy for neurodegenerative diseases mediated by microglial activation, such as Alzheimer's disease.

Hydroethanolic Extract of Salvia officinalis L. Leaves Improves Memory and Alleviates Neuroinflammation in ICR Mice

Neurodegenerative disorders are known to be commonly associated with neuroinflammation. Plants with antioxidant and anti-inflammatory properties hold prospect in alleviating neuroinflammation. One such plant with documented anti-inflammatory and antioxidant potential is Salvia officinalis L. This study looked at effects of the hydroethanolic leaf extract of S. officinalis L. on lipopolysaccharide (LPS)-induced neuroinflammation and associated memory impairment using an ICR mouse model. Assessment of the phytochemical constituents in S. officinalis L. and its acute toxicity was conducted. Mice were treated with S. officinalis L. extract (30, 100, and 300 mg/kg) after LPS administration. Object recognition and elevated plus maze tests were employed to assess neuroinflammation-induced behavioral changes. Brain samples were taken to determine the levels of TNF-α and conduct histopathological analysis. The hydroethanolic extract of S. officinalis L. was found to contain alkaloids, glycoside, tannins, flavonoids, and coumarins and exhibited no observable acute toxicity. The extract showed the presence of eicosatrienoic acid, methyl ester, and phenanthrene derivatives. The extract improved memory and cognitive performance but had no significant effect on brain tissue TNF-α expression. S. officinalis L. treatment in mice with neuroinflammation also resulted in reduced mononuclear infiltration and gliosis and reduced apoptotic and necrotic neurons as well as no observable brain lesions. S. officinalis L. holds promising pharmacological activity at reducing neuroinflammation and its associated cognitive impairment.

Association between cognitive functioning and microbiota-gut-brain axis mediators in a memory clinic population

Introduction

A growing body of evidence recognises the role of signaling molecule of the microbiota-gut-brain axis (MGBA) in cognitive impairment (CI), but data on the link with alterations in specific cognitive domains are limited. We compared the functioning in several cognitive domains (i.e., memory, visuo-constructional, executive, and language) among cognitively unimpaired (CU) subjects, patients with CI due to Alzheimer’s disease (CI-AD) and not due to AD (CI-NAD). Then, we investigated the association of these cognitive domains with the gut microbiota (GM), MGBA mediators, and neurodegeneration-related markers.

Materials and methods

The study included 34 CI-AD, 38 CI-NAD, and 13 CU. Memory, visuo-constructional, executive, and language domains were assessed using composite measures. Faecal GM composition was inferred using 16S rRNA gene sequencing. MGBA mediators included the blood quantification of bacterial products (lipolysaccharide, LPS), cell adhesion molecules indicative of endothelial damage, vascular changes or overexpressed in response to infections, and pro- and anti-inflammatory cytokines. Neurodegeneration-related markers included plasma phosphorylated tau (p-tau181), neurofilament light chain (NfL), and glial fibrillary protein (GFAP).

Results

The CI-NAD and CI-AD groups had significantly lower scores than the CU group for all cognitive domains (p < 0.043). Associations of MGBA modulators with cognitive functioning included pro-inflammatory cytokines, markers of endothelial dysfunction or overexpressed in response to infection in both groups of patients (|ρ| > 0.33, ps < 0.042). In the CU and CI-AD pooled group, lower cognitive functioning was specifically associated with higher abundance of Dialister and Clostridia_UCG-014, higher levels of LPS and with all neurodegeneration markers (|ρ| > 0.32, p < 0.048 for all). In the CU and CI-NAD pooled group, lower cognitive performance was associated with lower abundance of Acetonema, higher abundance of Bifidobacterium, [Eubacterium]_coprostanoligenes_group and Collinsella, and higher levels of vascular changes (|ρ| > 0.30, p < 0.049).

Discussion

These results support the hypothesis that gut dysbiosis and MGBA mediators may have distinct effects on cognitive functioning and different mechanisms of action depending on the disease.

The microbiome: what a neurologist needs to know

The gastrointestinal tract is inhabited by trillions of micro-organisms that form the gut microbiome, which serves various functions that can influence neurological pathways. It can release metabolites that could affect the nervous system. The bidirectional communication between the intestine and the central nervous system is known as the gut-brain axis. This communication can be impacted by the microbiota in various direct and indirect ways. There has been a suggested connection between the microbiome and many neurological disorders, including epilepsy, Alzheimer's disease, Parkinson's disease and multiple sclerosis. This has been explored in human and animal studies. While no microbial biomarkers have been identified yet, alterations in several taxa have been suggested to be associated with disease states. The potential of the microbiome to modulate neurological function has sparked multiple clinical trials using gut-altering treatments, some with positive preliminary results.

Protein disulfide isomerase integrates toll-like receptor 4 and P2X7 receptor signaling pathways during lipopolysaccharide-induced neuroinflammation

P2X7 receptor (P2X7R) augments lipopolysaccharide (LPS)-toll-like receptor 4 (TLR4)-mediated neuroinflammation. These roles of P2X7R in neuroinflammation are relevant to nitrosative stress through nuclear factor-κB (NF-κB)-inducible nitric oxide synthase (iNOS) pathway, while the underlying mechanisms are largely unknown. In the present study, we investigated whether protein disulfide isomerase (PDI) is involved in the integration of TLR4-P2X7R functions in response to LPS in vivo. The present study showed that LPS elicited NF-κB-mediated PDI upregulation, iNOS induction and S-nitrosylated PDI (SNO-PDI) level, independent of S-nitrosylation of NF-κB p65 subunit, in P2X7R+/+ mice more than P2X7R-/- mice. SN50 (an NF-κB inhibitor) effectively diminished LPS-induced PDI upregulation in both P2X7R+/+ and P2X7R-/- mice. PDI knockdown attenuated LPS-induced p65 S276 phosphorylation and iNOS induction in both strains. Of interest, S-nitroso-N-acetyl-DL-penicillamine (SNAP, a NO donor) increased SNO-PDI level, surface P2X7R expression and p65 S276 phosphorylation in P2X7R+/+ mice under physiological condition. In P2X7R-/- mice, SNAP was less effective on NF-κB S276 phosphorylation, although SNO-PDI level was similar to that in P2X7R+/+ mice. Taken together, the present data demonstrate that PDI may be an intermediator to integrate TLR4- and P2X7R-mediated signaling pathways in a positive feedback loop, which would exert NF-κB-iNOS-mediated nitrosative stress during LPS-induced neuroinflammation.

The acetyltransferase GCN5 contributes to neuroinflammation in mice by acetylating and activating the NF-κB subunit p65 in microglia

Neuroinflammation promotes the progression of various neurological and neurodegenerative diseases. Disrupted homeostasis of protein acetylation is implicated in neurodegeneration, and the lysine acetyltransferase GCN5 (also known as KAT2A) is implicated in peripheral inflammation. Here, we investigated whether GCN5 plays a role in neuroinflammation in the brain. Systemic administration of the bacterial molecule LPS in mice to induce peripheral inflammation increased the abundance of GCN5 in various organs, including in the brain and specifically in microglia. In response to LPS, GCN5 mediated the induction of the proinflammatory cytokines TNF-α and IL-6 and the inflammatory mediators COX-2 and iNOS in microglia. Further investigation in cultured microglial cells revealed that GCN5 was activated downstream of the innate immune receptor TLR4 to acetylate Lys310 in the NF-κB subunit p65, thereby enabling the nuclear translocation and transcriptional activity of NF-κB and the resulting inflammatory response. Thus, targeting GCN5 might be explored further as a strategy to reduce neuroinflammation in the treatment of associated diseases.

Investigation of the Immunomodulatory and Neuroprotective Properties of Nigella sativa Oil in Experimental Systemic and Neuroinflammation

Nigella sativa (NS) is a promising medicinal plant with diverse therapeutic properties. This study aimed to investigate the impact of NS oil (NSO) on memory functions in rats with LPS (lipopolysaccharide)-induced neuroinflammation, as well as its effect on serum levels of inflammatory cytokines, neuropeptide Y (NPY) and brain-derived neurotrophic factor (BDNF). Male rats were divided into four groups: control, LPS-control, LPS+NSO 3 and 5 mL/kg. Neuroinflammation was induced by a single intraperitoneal LPS injection (2 mg/kg). The novel object recognition test (NORT) and Y-maze were used for the evaluation of memory processes. Recognition index (RI) and % spontaneous alteration (%SA) were registered, respectively. Blood samples for TNF-α, IL-1β, IL-10, BDNF, and NPY serum levels were taken. Thymoquinone, the active compound of the oil, was detected by high-performance liquid chromatography. NSO administration resulted in an improvement in spatial and episodic memory, as evidenced by increased % SA and RI compared to LPS-control. Treatment with NSO led to a significant reduction in pro-inflammatory cytokines and NPY, along with an increase in IL-10 and BDNF levels, when compared to LPS-control. In conclusion, NSO enhances BDNF production and regulates pro- and anti-inflammatory cytokines release, which probably contributes to the observed cognitive improvement in animals with experimental neuroinflammation.

Role of glia in delirium: proposed mechanisms and translational implications

Delirium is a common acute onset neurological syndrome characterised by transient fluctuations in cognition. It affects over 20% of medical inpatients and 50% of those critically ill. Delirium is associated with morbidity and mortality, causes distress to patients and carers, and has significant socioeconomic costs in ageing populations. Despite its clinical significance, the pathophysiology of delirium is understudied, and many underlying cellular mechanisms remain unknown. There are currently no effective pharmacological treatments which directly target underlying disease processes. Although many studies focus on neuronal dysfunction in delirium, glial cells, primarily astrocytes, microglia, and oligodendrocytes, and their associated systems, are increasingly implicated in delirium pathophysiology. In this review, we discuss current evidence which implicates glial cells in delirium, including biomarker studies, post-mortem tissue analyses and pre-clinical models. In particular, we focus on how astrocyte pathology, including aberrant brain energy metabolism and glymphatic dysfunction, reactive microglia, blood-brain barrier impairment, and white matter changes may contribute to the pathogenesis of delirium. We also outline limitations in this body of work and the unique challenges faced in identifying causative mechanisms in delirium. Finally, we discuss how established neuroimaging and single-cell techniques may provide further mechanistic insight at pre-clinical and clinical levels.

Saccharomyces cerevisiae-derived vesicles loaded with dextromethorphan as a candidate for the management of neuroinflammation related to Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disease that is associated with neuroinflammation. Dextromethorphan (DXM) exerts neuroprotective effects in many central nervous system injuries and neurodegenerative diseases. The cell wall of Saccharomyces cerevisiae is a cell-based drug delivery system that can be a suitable candidate for targeted drug delivery to the site of inflammation. In this study, nanoparticles (NPs) were prepared from Saccharomyces cerevisiae cell walls, coated with polysorbate-80, and loaded with DXM. NPs had favorable hemolytic behavior with a particle size distribution of 187.25 ± 73.37 nm and a zeta potential of +4.3 mV. Pathological examination in a mouse model of neuroinflammation showed that NPs had the ability to reduce brain inflammation and the adverse effects of DXM.

Neuronal PLPP/CIN exaggerates the immune response of hippocampal microglia to LPS challenge dependent on PAK1-NF-κB-COX-2 signaling pathway

Recently, we have reported that pyridoxal-5'-phosphate phosphatase/chronophin (PLPP/CIN) selectively dephosphorylates neurofibromin 2 (NF2, also known as merlin) at serine (S) 10 site. Since NF2 inhibits p21-activated kinase 1 (PAK1)-mediated nuclear factor-κB (NF-κB) activation, in the present study, we investigated the role of PLPP/CIN-mediated NF2 S10 dephosphorylation in lipopolysaccharide (LPS)-induced neuroinflammation and explored its related signaling pathways in the mouse hippocampus. PLPP/CIN overexpression increased NF2 S10 dephosphorylation and PAK1 S204 autophosphorylation under physiological condition, which were reversed by PLPP/CIN deletion. Following LPS injection, PLPP/CIN overexpression exacerbated microglial activation, although microglial PLPP/CIN expression was undetectable. In addition, PLPP/CIN overexpression enhanced PAK1 and NF-κB phosphorylations, and upregulated cyclooxygenase-2 (COX-2) and prostaglandin E synthase 2 (PTGES2) expressions in CA1 neurons. PLPP/CIN overexpression also augmented microglial interleukin-1β induction. PLPP/CIN ablation and 1,1'-dithiodi-2-naphthtol (IPA-3, a PAK1 inhibitor) pretreatment ameliorated these LPS-induced neuroinflammatory responses. These findings indicate that PLPP/CIN-mediated NF2 S10 dephosphorylation may facilitate PAK1-NF-κB-COX-2-PTGES2 signaling pathway in CA1 neurons, which would subsequently exaggerate immune response of microglia following LPS treatment. Therefore, our findings suggest that this PLPP/CIN-mediated neuron-microglia interaction may play an important role in the pathogenesis of inflammation-related neurological diseases.

Olfaction-based learned preference assessment without the use of motivational fear or motivational weight loss

Introduction

Reliable assessments of learning ability in preclinical models are essential for studying neurodegenerative, developmental, and inflammatory disorders. However, many inbred strains of mice present background pathologies that interfere with traditional learning tests. The C57BL/6 J mouse, a widely used laboratory strain, sporadically develops auditory and visual impairments that complicate interpretation. In this study, we establish an olfaction-based learned preference protocol designed to evaluate learning ability independent of fear responses, motivational weight loss, or visual cues in C57BL/6 J mice.

Methods and results

Leveraging the species' natural preference for sweet flavors, we tested different sweeteners and confirmed their passive preference for sucrose was more robust than for saccharin or sucralose. We then trained mice to associate either lemon or rose scents with a sucrose paste reward, and tested whether they demonstrated a learned preference for the sucrose-associated scent over the neutral scent. Mice developed an appetitive olfactory preference for sucrose as a reward, in the absence of motivational weight loss, as measured by time spent exploring a three-chamber association box with access to both scents. We assessed whether this protocol discriminated learning deficit induced by lipopolysaccharide (LPS) administration.

Conclusion

We conclude that this protocol is a viable tool for assessing learning abilities in preclinical models with auditory or visual deficits, motor impairments, or an inability to tolerate motivational weight loss.

CPT1A ameliorates microglia-induced neuroinflammation via facilitating VDR succinylation

Neurodegenerative diseases, characterized by impairments in cognition, memory, and movement, are becoming increasingly prevalent due to population aging, posing a significant threat to public health. Extensive evidence suggests that neuroinflammation, mediated by microglia, plays a crucial role in the development of these diseases. Notably, the vitamin D receptor (VDR) has been shown to regulate microglia activation by controlling the function of neuroprotective vitamin D. This study aims to elucidate the potential of VDR in modulating neuroinflammation. To mimic neuroinflammation, BV2 cells were treated with lipopolysaccharide (LPS) for 12 h. Enzyme-linked immunosorbent assays (ELISAs) were used to measure the release of cytokines, including IL-1β, IL-2, IL-6, IL-10, IL-12, MCP-1, and TNF-α. Western blot assays were performed to assess relative protein expressions and succinylation modifications. Co-immunoprecipitation (Co-IP) experiments were conducted to determine the interaction between VDR and carnitine palmitoyltransferase 1A (CPT1A). Immunofluorescence staining was used to analyze the localization of VDR, CPT1A, COX-2, and CD11b. Our findings demonstrated that VDR expression was upregulated in BV2 cells exposed to LPS. Ectopic expression of VDR attenuated the inflammatory response and microglia activation. We discovered that carnitine palmitoyltransferase 1A (CPT1A) promoted VDR succinylation. Further investigations revealed that CPT1A enhanced VDR stability by binding to VDR, with lysine K117 being the primary succinylation site. Importantly, depletion of CPT1A abrogated the protective effects of VDR overexpression on microglia-mediated neuroinflammation. Our study highlighted that CPT1A functioned as a suppressor in neuroinflammation by facilitating VDR succinylation, offering potential therapeutic targets for the management of neurodegenerative diseases.

Quinoa Ethanol Extract Ameliorates Cognitive Impairments Induced by Hypoxia in Mice: Insights into Antioxidant Defense and Gut Microbiome Modulation

Quinoa, rich in pharmacologically active ingredients, possesses the potential benefit in preventing cognitive impairments induced by hypoxia. In this study, the efficacy of quinoa ethanol extracts (QEE) consumption (200 and 500 mg/kg/d, respectively) against hypobaric hypoxia (HH)-induced cognitive deficits in mice was investigated. QEE significantly ameliorated hypoxic stress induced by HH, as evidenced by improvements in baseline indices and reductions in hypoxia-inducible factor 1α levels. Furthermore, QEE enhanced antioxidant defense mechanisms, alleviated neuroinflammation in brain regions associated with memory, and improved HH-induced cognitive impairments by modulating the cyclic adenosine monophosphate response element-binding protein/brain-derived neurotrophic factor signaling pathway. Higher doses generally yielded more effective outcomes than lower doses. QEE also significantly reshaped the gut microbiome structure of HH mice, inhibited gut barrier damage, and reduced lipopolysaccharide migration, thereby increasing short-chain fatty acids (SCFAs) levels. Our findings suggest that QEE may be a promising strategy for preventing hypoxia-induced cognitive impairments by maintaining gut microbiome stability and increasing SCFAs levels.

PKR Inhibition Prevents Neuroinflammation and Rescues Depressive-Like Behaviors via BDNF/TrkB Signaling

PKR, a kinase implicated in inflammation, accumulates in the brain, but its role in neuroinflammation-related depression is poorly understood. This study aimed to investigate whether pharmacological PKR inhibition using C16 (PKR inhibitor) could reverse LPS-induced neuroinflammation and depressive-like behaviors. Mice (C57BL/6J, 20-22 g, 6-8 weeks old) were administered LPS intraperitoneally for three days to induce depressive-like behavior and neuroinflammation. Simultaneously, mice were treated with C16 (a pharmacological PKR inhibitor) intraperitoneally for the same duration, followed by behavioral assessments. After euthanasia, brain-hippocampus tissues were collected for biochemical analysis. To validate these in vivo findings, BV2 and HT22 cells were cultured and subjected to pharmacological and biochemical analysis. LPS treatment significantly increased hippocampal neuroinflammation (GFAP/IBA-1 p < 0.001), cytokine production (IL-1β, IL-6, TNF-α, p < 0.05), PKR phosphorylation (p < 0.05), and inflammatory signaling (NLRP3/ASC, p < 0.001). Concomitantly, LPS exposure induced depressive-like symptoms (p < 0.001), impaired synaptic function (Synasin-1/SNAP25, p < 0.05), spine numbers (p < 0.001), and downregulated brain-derived neurotrophic factor (BDNF) /TrkB signaling (p < 0.001). Importantly, these effects were attenuated by C16, a PKR inhibitor. C16 also reduced LPS-induced ER stress markers in the hippocampus (p < 0.05). Interestingly, K252a, a BDNF/TrkB inhibitor, reversed the protective effects of C16, increasing both neuroinflammation (p < 0.001) and depressive symptoms (p < 0.001) in LPS-treated mice. Notably, in vitro studies using BV2 and HT22 cells corroborated these findings. In conclusion, these findings suggest that PKR is critical in mediating LPS-induced neuroinflammation and depressive-like behaviors, potentially through interactions with BDNF/TrkB signaling.

Linking Gut Microbiota and Stereotypic Behavior of Endangered Species Under Ex Situ Conservation: First Evidence from Sun Bears

Integrative conservation research on animal behavior and nutritional health can contribute to the ex situ conservation of endangered species. Stereotypic behavior, a repetitive behavior without practical function, is associated with animal welfare in its manner and frequency for captive animals. Exploring the potential relationship between stereotypic behavior and internal factors, such as intestinal flora, could improve ex situ conservation, especially for endangered species. In this study, we analyzed the typical behavior characteristics of the endangered sun bears (Helarctos malayanus) under captive conditions based on the behavior sampling method. The seasonal and annual changes in the intestinal flora of H. malayanus in captivity were studied by 16S rDNA high-throughput sequencing technology based on non-invasive fecal sample collection. This study provides the first evidence of a potential association between the gut microbiota and stereotypic behavior characteristics of captive H. malayanus. The results can significantly improve our understanding of the stereotypical behavior of H. malayanus in captivity and contribute to the captive breeding and conservation efforts of this endangered species.

Hippocampal neuroinflammation induced by lipopolysaccharide causes sex-specific disruptions in action selection, food approach memories, and neuronal activation

Hippocampal neuroinflammation is present in multiple diseases and disorders that impact motivated behaviour in a sex-specific manner, but whether neuroinflammation alone is sufficient to disrupt this behaviour is unknown. We investigated this question here using mice. First, the application of an endotoxin to primary cultures containing only hippocampal neurons did not affect their activation. However, when the same endotoxin was applied to mixed neuronal/glial cultures it did increase neuronal activation, providing initial indications of how it might be able to effect behavioural change. We next showed neuroinflammatory effects on behaviour directly, demonstrating that intra-hippocampal administration of the same endotoxin increased locomotor activity and accelerated goal-directed learning in both male and female mice. In contrast, lipopolysaccharide-induced hippocampal neuroinflammation caused sex-specific disruptions to the acquisition of instrumental actions and to Pavlovian food-approach memories. Finally, we showed that LPS-induced hippocampal neuroinflammation had a sexually dimorphic effect on neuronal activation: increasing it in females and decreasing it in males.

Fecal Microbiota Transplantation Improves Cognitive Function of a Mouse Model of Alzheimer's Disease

BACKGROUND

A growing body of evidence suggests a link between the gut microbiota and Alzheimer's disease (AD), although the underlying mechanisms remain elusive. This study aimed to investigate the impact of fecal microbiota transplantation (FMT) on cognitive function in a mouse model of AD.

METHODS

Four-month-old 5 × FAD (familial Alzheimer's disease) mice underwent antibiotic treatment to deplete their native gut microbiota. Subsequently, they received FMT either weekly or every other day. After 8 weeks, cognitive function and β-amyloid (Aβ) load were assessed through behavioral testing and pathological analysis, respectively. The composition of the gut microbiota was analyzed using 16S rRNA sequencing.

RESULTS

Initial weekly FMT failed to alleviate memory deficits or reduce brain Aβ pathology in 5 × FAD mice. In contrast, FMT administered every other day effectively restored gut dysbiosis in 5 × FAD mice and decreased Aβ pathology and lipopolysaccharide levels in the colon and hippocampus. Mechanistically, FMT reduced the expression of amyloid β precursor protein, β-site APP cleaving enzyme 1, and presenilin-1, potentially by inhibiting the Toll-like receptor 4/inhibitor of kappa B kinase β/nuclear factor kappa-B signaling pathway. However, the cognitive benefits of FMT on 5 × FAD mice diminished over time.

CONCLUSION

These findings demonstrate the dose- and time-dependent efficacy of FMT in mitigating AD-like pathology, underscoring the potential of targeting the gut microbiota for AD treatment.

Interventional Effects of Edible Bird's Nest and Free Sialic Acids on LPS-Induced Brain Inflammation in Mice

Objectives: Our study investigated the effects and mechanisms of edible bird's nest (EBN) and free sialic acids (SA) on LPS-induced brain inflammation in mice. Methods: The experiment divided the mice into four groups: control group (CON), lipopolysaccharide group (LPS), EBN intervention group (EBN, 200 mg/kg/d in dry EBN), and sialic acid intervention group (SA, dosage was calibrated based on the concentration of sialic acid in EBN). Results: The results showed that LPS caused a decrease followed by upregulation in body weight in female mice, and EBN exhibited renal protective effects. In the Morris water maze, the learning and memory abilities of mice in the LPS group first declined and then recovered. At the same time, the escape latency improved in the EBN and SA groups. In the Open field test, both the EBN and SA groups exhibited anti-anxiety and anti-depressive effects. Immunohistochemistry in the hippocampus showed significant cell damage in the LPS group, while the damage was alleviated in the EBN and SA groups. LPS promoted the expression of TICAM1 and MYD88 in the NF-κB pathway, while both the EBN and SA groups could inhibit the expression of TICAM1. Conclusions: The study has found that both EBN and SA exhibited noteworthy anti-inflammatory effects, indicating that the main active component in EBN that provides neuroprotective effects is SA. The bound SA in EBN confers additional effects, supporting the development of prevention and treatment strategies for brain inflammation.

The Effect of Disulfiram and N-Acetylcysteine, Potential Compensators for Sulfur Disorders, on Lipopolysaccharide-Induced Neuroinflammation Leading to Memory Impairment and the Metabolism of L-Cysteine Disturbance

BACKGROUND

The role of sulfur-containing drugs, disulfiram (DSF) and N-acetylcysteine (NAC), in alleviating neuroinflammation is poorly understood. The objective of this study was to examine the effect of DSF and NAC on memory and on the metabolism of L-cysteine and inflammation-related parameters in the cerebral cortex of rats in a model of neuroinflammation induced by the administration of lipopolysaccharide (LPS).

METHODS

All the treatments were administered intraperitoneally for 10 days (LPS at a dose of 0.5 mg/kg b.w., DSF at a dose of 100 mg/kg b.w, and NAC at a dose of 100 mg/kg b.w.). Behavior was evaluated by the novel object recognition (NOR) test and object location (OL) test, and the level of brain-derived neurotrophic factor (BDNF) was assayed to evaluate neuronal functioning. Cerebral cortex homogenates were tested for hydrogen sulfide (H2S), sulfane sulfur, sulfates, non-protein sulfhydryl groups (NPSH), nitric oxide (NO), and reactive oxygen species (ROS) by biochemical analysis.

RESULTS

Neither DSF nor NAC alleviated LPS-induced memory disorders estimated by the NOR test and OL test. The studied compounds also did not affect significantly the levels of BDNF, ROS, NO, H2S, and sulfane sulfur in the cerebral cortex. However, we observed an increase in sulfate concentration in brain tissues after LPS treatment, while DSF and NAC caused an additional increase in sulfate concentration. On the other hand, our study showed that the administration of DSF or NAC together with LPS significantly enhanced the cortical level of NPSH, of which glutathione is the main component.

CONCLUSIONS

Our study did not confirm the suggested potential of DSF and NAC to correct memory disorders; however, it corroborated the notion that they reduced oxidative stress induced by LPS by increasing the NPSH level. Additionally, our study showed an increase in sulfate concentration in the brain tissues after LPS treatment, which means the upregulation of sulfite and sulfate production in inflammatory conditions.

Extended protective effects of three dimensional cultured human mesenchymal stromal cells in a neuroinflammation model

BACKGROUND

Human mesenchymal stromal cells (MSCs) possess regenerative potential due to pluripotency and paracrine functions. However, their stemness and immunomodulatory capabilities are sub-optimal in conventional two-dimensional (2D) culture.

AIM

To enhance the efficiency and therapeutic efficacy of MSCs, an in vivo-like 3D culture condition was applied.

METHODS

MSCs were cultured on polystyrene (2D) or in a gellan gum-based 3D system. In vitro, prostaglandin-endoperoxide synthase 2, indoleamine-2,3-dioxygenase, heme oxygenase 1, and prostaglandin E synthase gene expression was quantified by quantitative real-time polymerase chain reaction. MSCs were incubated with lipopolysaccharide (LPS)-treated mouse splenocytes, and prostaglandin E2 and tumor necrosis factor-alpha levels were measured by enzyme linked immunosorbent assay. In vivo, LPS was injected into the lateral ventricle of mouse brain, and MSCs were administered intravenously the next day. Animals were sacrificed and analyzed on days 2 and 6.

RESULTS

Gellan gum polymer-based 3D culture significantly increased expression of octamer-binding transcription factor 4 and Nanog homeobox stemness markers in human MSCs compared to 2D culture. This 3D environment also heightened expression of cyclooxygenase-2 and heme-oxygenase 1, enzymes known for immunomodulatory functions, including production of prostaglandins and heme degradation, respectively. MSCs in 3D culture secreted more prostaglandin E2 and effectively suppressed tumor necrosis factor-alpha release from LPS-stimulated splenocytes and surpassed the efficiency of MSCs cultured in 2D. In a murine neuroinflammation model, intravenous injection of 3D-cultured MSCs significantly reduced ionized calcium-binding adaptor molecule 1 and glial fibrillary acidic protein expression, mitigating chronic inflammation more effectively than 2D-cultured MSCs.

CONCLUSION

The microenvironment established in 3D culture serves as an in vivo mimetic, enhancing the immunomodulatory function of MSCs. This suggests that engineered MSCs hold significant promise a potent tool for cell therapy.

Iron Homeostasis Dysregulation, Oro-Gastrointestinal Microbial Inflammatory Factors, and Alzheimer's Disease: A Narrative Review

Alzheimer's disease (AD), the most common form of dementia, is a progressive neurodegenerative disorder that profoundly impacts cognitive function and the nervous system. Emerging evidence highlights the pivotal roles of iron homeostasis dysregulation and microbial inflammatory factors in the oral and gut microbiome as potential contributors to the pathogenesis of AD. Iron homeostasis disruption can result in excessive intracellular iron accumulation, promoting the generation of reactive oxygen species (ROS) and oxidative damage. Additionally, inflammatory agents produced by pathogenic bacteria may enter the body via two primary pathways: directly through the gut or indirectly via the oral cavity, entering the bloodstream and reaching the brain. This infiltration disrupts cellular homeostasis, induces neuroinflammation, and exacerbates AD-related pathology. Addressing these mechanisms through personalized treatment strategies that target the underlying causes of AD could play a critical role in preventing its onset and progression.

Effect of simultaneous application of adenosine A1 receptor agonist and A2A receptor antagonist on memory, inflammatory factors, and PSD-95 in lipopolysaccharide-induced memory impairment

The potential role of adenosine, a natural neuroprotective agent, and its receptors in the pathogenesis of Alzheimer's disease has been proposed. The present study aims to examine the effect of administering both an A1 receptor agonist and an A2A adenosine receptor antagonist simultaneously on memory, inflammatory factors, and PSD-95 in an LPS-induced Alzheimer's disease model in rats. Fifty-six male Wistar rats were randomly divided into seven groups: Saline, LPS, Saline + Vehicle, LPS + Vehicle, LPS + SCH58261 (A2A receptor antagonist), LPS + CPA (A1 receptor agonist), LPS + SCH58261+CPA. LPS (3 mg/kg/ip) was used to cause memory impairment. Treatment was performed by intraventricular injection of CPA at a dose of 700 μg and SCH-58261 at 40 μg for ten days. Passive avoidance and Y-maze tests were performed to examine animals' memories. IL-10, TNF-α, and PSD-95 levels were measured in the brain using ELISA and western blot, respectively. Compared to the groups receiving each medication separately, the simultaneous administration of CPA and SCH58261 improved memory (P<0.05). Additionally, compared to the single medication groups, there was a significant increase in IL-10, PSD-95, and a significant decrease in TNF-α in the brain tissue (P<0.05). These findings suggest that the activation of A1 receptors along with A2A receptor inhibition could be a potential therapeutic strategy for Alzheimer's disease. These findings suggest that A1 receptor activation combined with A2A receptor inhibition may be a promising therapeutic approach for Alzheimer's disease.

Remimazolam attenuates lipopolysaccharide-induced neuroinflammation and cognitive dysfunction

OBJECTIVE

Remimazolam, a novel benzodiazepine, is widely used as an anesthetic in endoscopic procedures; however, its effects on cognitive function remain unclear, limiting its broader application in general anaesthesia. Neuroinflammation is a well-established key factor in the etiology and progression of cognitive dysfunction, including conditions such as Alzheimer's disease, Parkinson's disease, postoperative delirium, and postoperative cognitive dysfunction. Preclinical studies have demonstrated that remimazolam exerts anti-inflammatory and neuroprotective effects, and clinical reports indicate a reduced incidence of postoperative delirium in patients treated with remimazolam. Nevertheless, whether remimazolam improves cognitive function through its anti-inflammatory properties remains uncertain. This study aimed to investigate the neuroprotective effects of remimazolam and its underlying mechanism in a lipopolysaccharide (LPS)-induced model of neuroinflammation, neuronal injury, and cognitive dysfunction METHODS: C57BL/6 J male mice were administered LPS intraperitoneally to establish a model of neuroinflammation-induced cognitive impairment. A subset of mice received remimazolam via intraperitoneal injection 30 minutes prior to LPS administration. Cognitive performance was evaluated using behavioural tests, including the Morris Water Maze (MWM), Novel Object Recognition (NOR) test, and Open Field Test (OFT). Hippocampal tissues were analyzed by haematoxylin-eosin (HE) staining to assess structural changes. Inflammatory markers, including Interleukin (IL)-6, IL-1β, and tumor necrosis factor-α, were quantified using enzyme-linked immunosorbent assay (ELISA) and real-time quantitative PCR. Immunofluorescence was used to detect translocator protein (TSPO) and markers of microglia activation (IBA-1, CD16/32, and CD206).

RESULTS

(1) Remimazolam reversed LPS-induced cognitive deficits, as evidenced by shorter spatial exploration latency and increased platform crossings in the MWM, and an elevated recognition index in the NOR test. (2) Remimazolam improved hippocampal morphology, reducing LPS-induced neuronal damage. (3) Remimazolam significantly decreased levels of hippocampal inflammatory cytokines, inhibited microglial activation, promoted M2-type microglia polarization, and increased TSPO expression.

CONCLUSION

Remimazolam demonstrated neuroprotective and anti-neuroinflammatory effects in a mouse model of LPS-induced cognitive impairment. These effects are likely mediated through the regulation of TSPO, which inhibits microglial activation and promotes the polarization of microglia from the pro-inflammatory M1 phenotype to the anti-inflammatory M2 phenotype.

A Comprehensive Review on Preclinical Alzheimer's Disease Models: Evaluating their Clinical Relevance

Alzheimer's disease (AD) is a neurological disorder that increases with age and must be treated immediately by worldwide healthcare systems. Internal neurofibrillary tau tangles and extracellular amyloid accumulation have been widely recognized as the primary causes of Alzheimer's disease. These degenerative age-related ailments are expected to proliferate exponentially as life expectancy rises. Experimental models of AD are essential for acquiring a deep knowledge of its pathogenesis and determining the viability of novel therapy options. Although there isn't a model that encompasses all the characteristics of real AD, these models are nonetheless highly helpful for the research of various modifications associated with it, even though they are only partially indicative of the disease circumstances being studied. Better knowledge of the advantages and disadvantages of each of the different models, as well as the use of more than one model to evaluate potential medications, would increase the effectiveness of therapy translation from preclinical research to patients. We outline the pathogenic characteristics and limitations of the main experimental models of AD in this review, including transgenic mice, transgenic rats, primates and non-primate models along with in-vitro cell culture models in humans. Additionally, it highlights the possible future of experimental modeling of AD and includes the co-morbid models.

From Gut Microbiomes to Infectious Pathogens: Neurological Disease Game Changers

Gut microbiota and infectious diseases affect neurological disorders, brain development, and function. Compounds generated in the gastrointestinal system by gut microbiota and infectious pathogens may mediate gut-brain interactions, which may circulate throughout the body and spread to numerous organs, including the brain. Studies shown that gut bacteria and disease-causing organisms may pass molecular signals to the brain, affecting neurological function, neurodevelopment, and neurodegenerative diseases. This article discusses microorganism-producing metabolites with neuromodulator activity, signaling routes from microbial flora to the brain, and the potential direct effects of gut bacteria and infectious pathogens on brain cells. The review also considered the neurological aspects of infectious diseases. The infectious diseases affecting neurological functions and the disease modifications have been discussed thoroughly. Recent discoveries and unique insights in this perspective need further validation. Research on the complex molecular interactions between gut bacteria, infectious pathogens, and the CNS provides valuable insights into the pathogenesis of neurodegenerative, behavioral, and psychiatric illnesses. This study may provide insights into advanced drug discovery processes for neurological disorders by considering the influence of microbial communities inside the human body.

IUPHAR review: Targeted therapies of signaling pathways based on the gut microbiome in autism spectrum disorders: Mechanistic and therapeutic applications

Autism spectrum disorders (ASD) are complex neurodevelopmental disorders characterized by impairments in social interaction, communication and repetitive activities. Gut microbiota significantly influences behavior and neurodevelopment by regulating the gut-brain axis. This review explores gut microbiota-influenced treatments for ASD, focusing on their therapeutic applications and mechanistic insights. In addition, this review discusses the interactions between gut microbiota and the immune, metabolic and neuroendocrine systems, focusing on crucial microbial metabolites including short-chain fatty acids (SCFAs) and several neurotransmitters. Furthermore, the review explores various therapy methods including fecal microbiota transplantation, dietary modifications, probiotics and prebiotics and evaluates their safety and efficacy in reducing ASD symptoms. The discussion shows the potential of customized microbiome-based therapeutics and the integration of multi-omics methods to understand the underlying mechanisms. Moreover, the review explores the intricate relationship between gut microbiota and ASD, aiming to develop innovative therapies that utilize the gut microbiome to improve the clinical outcomes of ASD patients. Microbial metabolites such as neurotransmitter precursors, tryptophan metabolites and SCFAs affect brain development and behavior. Symptoms of ASD are linked to changes in these metabolites. Dysbiosis in the gut microbiome may impact neuroinflammatory processes linked to autism, negatively affecting immune signaling pathways. Research indicates that probiotics and prebiotics can improve gut microbiota and alleviate symptoms in ASD patients. Fecal microbiota transplantation may also improve behavioral symptoms and restore gut microbiota balance. The review emphasizes the need for further research on gut microbiota modification as a potential therapeutic approach for ASD, highlighting its potential in clinical settings.

Time- and Region-specific Effect of Vortioxetine on Central LPS-induced Transcriptional Regulation of NLRP3 Inflammasome

BACKGROUND

Inflammasome overactivation, multiprotein complexes that trigger inflammatory responses, plays a critical role in Major Depressive Disorder (MDD) pathogenesis and treatment responses. Indeed, different antidepressants alleviate depression-related behaviours by specifically counteracting the NLRP3 inflammasome signalling pathway. The immunomodulatory effects of vortioxetine (VTX), a multimodal antidepressant with cognitive benefits, were recently revealed to counter memory impairment induced by a peripheral lipopolysaccharide (LPS) injection 24 hours (h) postchallenge. The potential link between VTX and NLRP3, along with other inflammasomes, remains un-explored.

METHODS

The potential link between VTX and NLRP3, along with other inflammasomes, remains unexplored. Hence, adult C57BL/6J male mice (n = 73) were fed with a standard or VTX-enriched diet (600 mg/kg of food, 28 days), injected with LPS (830 μg/kg) or saline, and sacrificed 6/24 h post-LPS. At these time-points, transcriptional effects of LPS and VTX on NLRP3, NLRP1, NLRC4, AIM2 (inflammasomes), ASC and CASP1 (related subunits) and NEK7 mediator (NLRP3 regulator) were assessed in dorsal and ventral hippocampal subregions, frontal-prefrontal cortex and hypothalamus, brain regions serving behavioural-cognitive functions impaired in MDD.

RESULTS

Varied expression patterns of inflammasomes were revealed, with long-term NLRP3 and ASC transcriptional changes observed in response to LPS. It was demonstrated that VTX counteracted the LPS-mediated NLRP3 and ASC upregulation in memory-related brain areas like the dorsal hippocampus at 24 h time-point, potentially via regulating NEK7 expression. No VTX-mediated transcriptional effects were observed on other inflammasomes, reinforcing a potentially specific modulation on the NLRP3 inflammasome signalling pathway.

CONCLUSION

Thus, a novel VTX molecular mechanism in modulating the NLRP3 inflammasome in a time- and area-specific manner in the brain was highlighted, with significant clinical implications in treating depression and cognitive impairments.

Discovery of gallic acid-based mitochondriotropic antioxidant attenuates LPS-induced neuroinflammation

Mitochondria are complex organelle that plays a pivotal role in energy metabolism, regulation of stress responses, and also serve as a major hub for biosynthetic processes. In addition to their well-established function in cellular energetics, it also serves as the primary site for the origin of intracellular reactive oxygen species (ROS), which function as signaling molecules and can lead to oxidative stress when generated in excess. Moreover, mitochondrial dysfunction is one of the leading cause of neuroinflammation. In this regard, we have rationally designed a triazine derived mitochondriotropic antioxidants (Mito-TBA), based on gallic acid and triphenylphosphonium (TPP) cation to specifically target mitochondria to mitigate neuroinflammation. In vitro Mito-TBA-3 inhibits mitoautophagy, offers neuroprotection by inhibiting the LPS induced TLR-4 activation and activating the Nrf-2/ARE pathway in PC-12 derived neurons. In vivo Mito-TBA-3 rescue memory deficit, reversed depression like behavior, inhibited neuroinflammation, and decreased proinflammatory cytokines in LPS induced neuroinflammation rat model. Overall, based on biophysical, in vitro and in vivo analysis, Mito-TBA-3 offers valuable insights as a potent therapeutic lead molecule to combat neurodegeneration even outperforming a well-known non-steroidal anti-inflammatory drug (Aspirin), it also has the potential to use as a promising therapeutic candidate for other mitochondrial oxidative stress related disorders.

Probiotics: A potential strategy for improving diabetes mellitus complicated with cognitive impairment

Diabetes mellitus (DM) is a common metabolic disease and one of the diseases with the highest number of complications at present. As the disease progresses, patients will gradually develop diabetes-related cognitive decline, mild cognitive impairment (MCI) or even dementia. The occurrence of diabetes-combined cognitive impairment undoubtedly imposes a heavy burden on patients and their families. Current research suggests that risk factors such as blood glucose levels, insulin resistance, oxidative stress and neuroinflammation have an important role in the development of diabetic cognitive impairment (DCI). With the development of technology and in-depth research, the relationship between the two-way communication between the gut and the brain has been gradually revealed, and more studies have found that the gut microbiota plays an important role in the development of DCI. This review explores the feasibility of probiotics as a potential strategy to assist in the improvement of DCI and its potential mechanisms from the perspective of the factors affecting DCI.

Mitochondria at the crossroad of dysregulated inflammatory and metabolic processes in bipolar disorders

In last few decades, considerable evidence has emphasized the significant involvement of mitochondria, often referred to as the "powerhouse of the cell," in the pathophysiology of bipolar disorder (BD). Given crucial mitochondrial functions in cellular metabolism and inflammation, both of which are compromised in BD, this perspective review examines the central role of mitochondria in inflammation and metabolism within the context of this disorder. We first describe the significance of mitochondria in metabolism before presenting the dysregulated inflammatory and metabolic processes. Then, we present a synthetic and hypothetical model of the importance of mitochondria in those dysfunctional pathways. The article also reviews different techniques for assessing mitochondrial function and discuss diagnostic and therapeutic implications. This review aims to improve the understanding of the inflammatory and metabolic comorbidities associated with bipolar disorders along with mitochondrial alterations within this context.

Protocol for the longitudinal study of neuroinflammation and reactive astrocytes in Lcn2CreERT2 mice

During brain disease, astrocytes can reprogram into a reactive state that alters many of their functions. Here, we present a protocol for studying neuroinflammation and reactive astrogliosis in mice using lipopolysaccharide (LPS) from E. coli. We describe steps for employing the Lcn2CreERT2 mouse crossed into a fluorescent Cre reporter line to label a subset of reactive astrocytes during and after inflammation. We then detail procedures for the longitudinal study of reactive astrocytes during the induction, progression, and/or resolution of astrogliosis. For complete details on the use and execution of this protocol, please refer to Agnew-Svoboda et al.1.

Effective Nose-to-Brain Delivery of Blood-Brain Barrier Impermeant Anti-IL-1β Antibody via the Minimally Invasive Nasal Depot (MIND) Technique

Treatment of neuroinflammation and neurodegenerative diseases using biologic therapies is limited due to the blood-brain barrier (BBB). This study explores a clinically validated approach to bypass the BBB for the purposes of direct central nervous system (CNS) delivery of antibodies using the Minimally Invasive Nasal Depot (MIND) technique. Using a lipopolysaccharide (LPS)-induced mouse model of neuroinflammation, we evaluated the efficacy of MIND in delivering a BBB impermeant full-length anti-IL-1β antibody. The results demonstrated that MIND delivery resulted in a significant reduction in IL-1β levels and microglial activation in relevant brain regions, notably outperforming conventional intravenous (IV) administration. These results underscore the ability of the MIND approach to transform the treatment landscape for a range of neurodegenerative diseases by enabling the targeted delivery of otherwise BBB impermeant therapeutics.

From Nutritional Patterns to Behavior: High-Fat Diet Influences on Inhibitory Control, Brain Gene Expression, and Metabolomics in Rats

Impulsive and compulsive behaviors are associated with inhibitory control deficits. Diet plays a pivotal role in normal development, impacting both physiology and behavior. However, the specific effects of a high-fat diet (HFD) on inhibitory control have not received adequate attention. This study aimed to explore how exposure to a HFD from postnatal day (PND) 33 to PND77 affects impulsive and compulsive behaviors. The experiment involved 40 Wistar rats subjected to HFD or chow diets. Several tasks were employed to assess behavior, including variable delay to signal (VDS), five choice serial reaction time task (5-CSRTT), delay discounting task (DDT), and rodent gambling task (rGT). Genetic analyses were performed on the frontal cortex, and metabolomics and fatty acid profiles were examined by using stool samples collected on PND298. Our results showed that the HFD group exhibited increased motor impulsive behaviors while not affecting cognitive impulsivity. Surprisingly, reduced impulsive decision-making was shown in the HFD group. Furthermore, abnormal brain plasticity and dopamine gene regulation were shown in the frontal cortex, while metabolomics revealed abnormal fatty acid levels.

Nicotinamide mononucleotide mitigates neuroinflammation by enhancing GPX4-mediated ferroptosis defense in microglia

BACKGROUND

Numerous neurological diseases involving neuroinflammation, particularly microglia, contribute to neuronal death. Ferroptosis is implicated in various diseases characterized by neuronal injury. Studies showed that nicotinamide mononucleotide (NMN) inhibits both neuroinflammation and ferroptosis. However, the mechanisms of NMN in both ferroptosis and neuroinflammation remain unclear. We aimed to explore the effects of NMN on neuroinflammation and the susceptibility of microglia to ferroptosis.

METHODS

Ferroptosis markers in macroglia exposed to lipopolysaccharides (LPS) were analyzed using CCK8, flow cytometry, ELISA, and quantitative RT-PCR. The effects of NMN on LPS-induced ferroptosis in microglia were evaluated through flow cytometry, western blot, and immunofluorescence staining. RT-PCR analysis assessed the inflammatory cytokine production of microglia subjected to Ferrostatin-1-regulated ferroptosis. RNA sequencing elucidated the underlying mechanism of NMN-involved microglia ferroptosis under LPS induction. In BV2 microglia, an inhibitor of GPX4, RSL3, was employed to suppress GPX4 expression. Intracerebroventricular injection of LPS was performed to evaluate neuroinflammation and microglia activation in vivo.

RESULTS

NMN effectively rescued LPS-induced ferroptosis and improved cell viability in microglia. Co-administration of NMN and ferrostatin-1 significantly reduced proinflammatory cytokine production in microglia following the introduction of LPS stimuli. Mechanistically, NMN facilitated glutathione (GSH) production, and enhanced resistance to lipid peroxidation occurred in a manner dependent on GPX4, repressing cytokine transcription and protecting cells from ferroptosis. RNA sequencing elucidated the underlying mechanism of NMN-associated microglia ferroptosis under LPS induction. Furthermore, simultaneous injection of NMN ameliorated LPS-induced ferroptosis and neuroinflammation in mouse brains. The data from the present study indicated that NMN enhances GPX4-mediated ferroptosis defense against LPS-induced ferroptosis in microglia by recruiting GSH, thereby inhibiting neuroinflammation.

CONCLUSION

Therapeutic approaches to effectively target ferroptosis in diseases using NMN, consideration should be given to both its anti-ferroptosis and anti-inflammatory effects to attain optimal outcomes, presenting promising strategies for treating neuroinflammation-related diseases or disorders.

Research hotspots and trends on NF-κB in cognitive impairment: a bibliometric analysis

Background

Cognitive impairment (CI) endangers the physical and mental health of patients in a significant manner, and it is expected that the number of people with CI in China will rise to 45.33 million by 2050. Therefore, CI has become a popular research topic. Inflammatory damage plays a key role in the pathogenesis of CI, and NF-κB is an important inflammatory signaling pathway. However, no bibliometric analysis regarding the relationship between CI and NF-κB has been reported.

Methods

A bibliometric analysis regarding NF-κB and CI from 1 January 2008 to 12 December 2023 was conducted in the Science Citation Index-Expanded of the Web of Science Core Collection. The frontiers, hotspots, and trends of research regarding the role of NF-κB in CI were identified. VOSviewer and CiteSpace were used to analyze the retrieved articles and identify the author, country, institution, and keywords, as well as co-cited authors, co-cited journals, and co-cited references.

Results

We analyzed 1,468 original articles and reviews. Publications on NF-κB in CI began in 2010 and increased sharply in 2018. Hong Hao was the most represented author, having published 19 articles, and Chinese authors published more studies than those from other countries. China Pharmaceutical University published the most papers; however, the United States has a strong influence and demonstrates international cooperation. The keywords "apolipoprotein e" and "therapeutic target" demonstrated strong citation bursts, and this tendency may persist in the upcoming years. Neuroinflammation demonstrated a strong influence in research regarding NF-κB in CI. Gut microbiota and ketogenic diet also play an important role in NF-κB in CI.

Conclusion

This bibliometric analysis and visualization using VOSviewer and CiteSpace revealed that the role of NF-κB in CI has become a research hotspot. The results of this study indicated that "neuroinflammation," "microglial," and "pathway" remain hotspots for future research. However, studies regarding NF-κB in CI have predominantly focussed on basic research; future research should include therapeutic targets, microbiota, and ketogenic diet.

Circulating inflammatory and neurotrophic markers as moderators and/or mediators of cognitive remediation outcome in people with bipolar disorders

BACKGROUND

Immune dysregulation appears involved in affective disorder pathophysiology. Inflammatory biomarkers have been linked with the cognitive impairment observed in people with bipolar disorders and as such are candidate markers that may improve with, and/or predict outcomes to, cognitive remediation therapies (CRT).

AIMS

Nine candidate biomarkers were examined as putative mediators and/or moderators to improvements following CRT compared with treatment as usual (TAU) from a randomised controlled trial.

METHOD

Euthymic adults with bipolar disorders who had been randomised to CRT (n = 23) or TAU (n = 21) underwent blood testing before and after a 12 week intervention period. Five cytokines and four growth factor proteins, selected a priori, were examined in association with global cognition and psychosocial functioning outcomes.

RESULTS

CRT attenuated a reduction in the brain-derived neurotrophic factor (BDNF), basic fibroblast growth factor and vascular endothelial growth factor-C compared to TAU. For the BDNF, lower baseline levels predicted better functional outcomes across the sample but was more pronounced in TAU versus CRT participants and indicated larger CRT effects in those with a higher BDNF. A moderation effect was also apparent for tumour necrosis factor-β and interleukin-16, with greater CRT versus TAU effects on functioning for participants with lower baseline levels.

CONCLUSIONS

Although preliminary, results suggest that CRT may exert some protective biological effects, and that people with lower levels of neurotrophins or cytokines may benefit more from CRT. We note an absence of associations with cognitive (versus functional) outcomes. These findings require further examination in large well-controlled studies.

Fasudil attenuates lipopolysaccharide-induced cognitive impairment in C57BL/6 mice through anti-oxidative and anti-inflammatory effects: Possible role of aquaporin-4

Introduction

Processes that generate systemic inflammation are strongly associated with neurodegenerative diseases. This study aimed to explore the potential anti-oxidative and anti-inflammatory effects of fasudil and its role in modulating aquaporin-4 (AQP-4) to improve cognitive impairment in a systemic inflammation model induced by lipopolysaccharide (LPS).

Method

fourty C57BL/6 mice were assigned to four groups, including sham, LPS, sham+fasudil, and LPS+fasudil). Intraperitoneal LPS was given (500 μg/kg/day) at hours 0, 24, 48, and 72, and fasudil (30 mg/kg) administered intraperitoneal injections 2 hours after LPS injection. The open field, Y-maze, and Novel object tasks was used to assess learning and memory. The levels of malondialdehyde (MDA), superoxide dismutase (SOD), interleukin-10 (IL-10), and tumor necrosis factor-α (TNF-α) in the hippocampus also measured as markers of oxidative stress and inflammation. Furthermore, the expression of AQP-4 measured in the intact and experimental groups.

Results

The results showed that Fasudil significantly improved memory and anxiety behavior induced by LPS in the open field maze, spatial recognition memory in the Y-maze, and performance in the novel object recognition task. It also mitigates hippocampal MDA and SOD levels. Additionally, fasudil ameliorated LPS-induced hippocampal levels of TNFα and IL-10 and increased hippocampal levels of AQP-4 expression in mice.

Conclusion

Our results suggest that fasudil in the LPS model of systemic inflammation could improve cognition by suppressing oxidative stress and inflammation and increasing AQP-4 protein expression. These findings highlighted the potential of fasudil as a neuroprotective agent. However, further research is required to fully understand its neuroprotective properties in the treatment of neurodegenerative disorders.

Glymphatic system: a gateway for neuroinflammation

The glymphatic system is a relatively recently identified fluid exchange and transport system in the brain. Accumulating evidence indicates that glymphatic function is impaired not only in central nervous system disorders but also in systemic diseases. Systemic diseases can trigger the inflammatory responses in the central nervous system, occasionally leading to sustained inflammation and functional disturbance of the central nervous system. This review summarizes the current knowledge on the association between glymphatic dysfunction and central nervous system inflammation. In addition, we discuss the hypothesis that disease conditions initially associated with peripheral inflammation overwhelm the performance of the glymphatic system, thereby triggering central nervous system dysfunction, chronic neuroinflammation, and neurodegeneration. Future research investigating the role of the glymphatic system in neuroinflammation may offer innovative therapeutic approaches for central nervous system disorders.

The gut microbiota as a link between Alzheimer's disease and obesity

Alzheimer's disease (AD) is a degenerative disease that causes a progressive decline in memory and thinking skills. Over the past few years, diverse studies have shown that there is no single cause of AD; instead, it has been reported that factors such as genetics, lifestyle, and environment contribute to the pathogenesis of the disease. In this sense, it has been shown that obesity during middle age is one of the most prominent modifiable risk factors for AD. Of the multiple potential mechanisms linking obesity and AD, the gut microbiota (GM) has gained increasing attention in recent years. However, the underlying mechanisms that connect the GM with the process of neurodegeneration remain unclear. Through this narrative review, we present a comprehensive understanding of how alterations in the GM of people with obesity may result in systemic inflammation and affect pathways related to the pathogenesis of AD. We conclude with an analysis of the relationship between GM and insulin resistance, a risk factor for AD that is highly prevalent in people with obesity. Understanding the crosstalk between obesity, GM, and the pathogenesis of AD will help to design new strategies aimed at preventing neurodegeneration.

Transplant of fecal microbiota from healthy young mice relieves cognitive defects in late-stage diabetic mice by reducing metabolic disorders and neuroinflammation

Fecal microbiota transplant (FMT) is becoming as a promising area of interest for treating refractory diseases. In this study, we investigated the effects of FMT on diabetes-associated cognitive defects in mice as well as the underlying mechanisms. Fecal microbiota was prepared from 8-week-aged healthy mice. Late-stage type 1 diabetics (T1D) mice with a 30-week history of streptozotocin-induced diabetics were treated with antibiotics for 7 days, and then were transplanted with bacterial suspension (100 μL, i.g.) once a day for 14 days. We found that FMT from healthy young mice significantly alleviated cognitive defects of late-stage T1D mice assessed in Morris water maze test. We revealed that FMT significantly reduced the relative abundance of Gram-negative bacteria in the gut microbiota and enhanced intestinal barrier integrity, mitigating LPS translocation into the bloodstream and NLRP3 inflammasome activation in the hippocampus, thereby reducing T1D-induced neuronal loss and astrocytic proliferation. FMT also reshaped the metabolic phenotypes in the hippocampus of T1D mice especially for alanine, aspartate and glutamate metabolism. Moreover, we showed that application of aspartate (0.1 mM) significantly inhibited NLRP3 inflammasome activation and IL-1β production in BV2 cells under a HG/LPS condition. We conclude that FMT can effectively relieve T1D-associated cognitive decline via reducing the gut-brain metabolic disorders and neuroinflammation, providing a potential therapeutic approach for diabetes-related brain disorders in clinic.