Integrated communications between cyclooxygenase-2 and Alzheimer's disease

Association between the COX-2 rs689466 polymorphism and antipsychotic treatment: Impact on HDL cholesterol changes in clozapine-treated psychosis patients

Several studies have shown antipsychotic effects of the selective cyclooxygenase-2 (COX-2) inhibitor celecoxib as an add-on treatment to antipsychotic treatment. The functional rs689466 (A/G) polymorphism in the gene encoding COX-2 (also known as the prostaglandin-endoperoxide synthase 2 gene) has been correlated with schizophrenia risk and the niacin skin flush response among chronic patients under antipsychotic treatment. Here, we investigated whether this polymorphism was associated with antipsychotic treatment in a group of total psychosis patients (N = 186), as well as a subgroup of patients treated with clozapine (N = 74). Antipsychotic-naïve first-episode patients and non-adherent chronic psychosis patients were genotyped by polymerase chain reaction/restriction fragment length polymorphism analysis. At baseline and after 8 weeks of treatment with various antipsychotic medications, we assessed the patients' Positive and Negative Syndrome Scale (PANSS) scores, factors, and metabolic syndrome-related parameters, including fasting plasma lipid and glucose levels and body mass index. In the total patient group, the COX-2 polymorphism was not associated with PANSS psychopathology scores or metabolic parameters. However, in the subgroup of patients treated with clozapine, the COX-2 polymorphism was associated with changes in plasma HDL cholesterol. Specifically, compared to patients homozygous for the A allele, the subgroup of patients treated with clozapine and positive for the G allele (i.e., GG or AG genotype) exhibited significantly higher increases in HDL cholesterol levels. The COX-2 polymorphism had a moderate effect size but made a relatively weak contribution to variations in the HDL cholesterol level (∼9.6 %).

Association between pulmonary ventilation function and cognitive function among middle-aged and older adults: an observational study from Southwest China

BACKGROUND

Despite the significant prevalence of chronic obstructive pulmonary disease (COPD) in Southwest China, cognitive function among middle-aged and elderly individuals in this area surpasses the national average. This study aims to reveal the overall pulmonary ventilation function status of this population, and investigate whether pulmonary ventilation dysfunction is a risk factor for mild cognitive impairment (MCI) in this region, as suggested by previous researches.

METHODS

Data were obtained from the 2019-2021 baseline survey of a natural population cohort study conducted in Southwest China. Pulmonary function was tested by experienced and well-trained medical personnel using a spirometer. The Mini-Mental State Examination was used to evaluate cognitive function. Subsequently, multiple logistic regression analysis was employed to examine the associations between pulmonary function and cognitive levels.

RESULTS

A total of 2,337 middle-aged and elderly adults were included in this study, with 10.18% (238 individuals) classified as having mild cognitive impairment. According to the Chinese experts' consensus on the standardization of adult lung function diagnosis, approximately 41.16% (962/2,337) of middle-aged and elderly individuals in Southwest China suffer from pulmonary ventilation dysfunction, predominantly mild (37.53%, 877/2,337), with the primary type being obstructive ventilation dysfunction (38.60%, 902/2,337; COPD: 14.21%, 332 participants). And 81.56% participants (1,906/2,337) were found to have small airway dysfunction. Multiple logistic regression analyses showed that individuals with poor pulmonary ventilation function (PPF) were associated with an increased risk of MCI (OR [95% CI]: 1.38 [1.04, 1.83], P = 0.026). Moreover, the more severe the pulmonary ventilation dysfunction, the higher the risk of cognitive impairment (P for trend = 0.009). Similar association were found between PPF and MCI when we use ATS/ERS technical standards. No significant association was observed between small airway dysfunction and cognitive impairment (OR [95% CI]: 1.05 [0.72, 1.56], P = 0.819).

CONCLUSIONS

The pulmonary function status of middle-aged and elderly individuals in Southwest China requires attention, particularly regarding obstructive pulmonary ventilation dysfunction. We recommend integrating pulmonary health assessments into routine care for these populations to raise awareness of lung health, improve lung function, and ultimately enhance cognitive function.

Insulin resistance as the molecular link between diabetes and Alzheimer's disease

Diabetes mellitus (DM) and Alzheimer's disease (AD) are two major health concerns that have seen a rising prevalence worldwide. Recent studies have indicated a possible link between DM and an increased risk of developing AD. Insulin, while primarily known for its role in regulating blood sugar, also plays a vital role in protecting brain functions. Insulin resistance (IR), especially prevalent in type 2 diabetes, is believed to play a significant role in AD's development. When insulin signalling becomes dysfunctional, it can negatively affect various brain functions, making individuals more susceptible to AD's defining features, such as the buildup of beta-amyloid plaques and tau protein tangles. Emerging research suggests that addressing insulin-related issues might help reduce or even reverse the brain changes linked to AD. This review aims to explore the rela-tionship between DM and AD, with a focus on the role of IR. It also explores the molecular mechanisms by which IR might lead to brain changes and assesses current treatments that target IR. Understanding IR's role in the connection between DM and AD offers new possibilities for treatments and highlights the importance of continued research in this interdisciplinary field.

A Fast-Binding, Functionally Reversible, COX-2 Radiotracer for CNS PET Imaging

Cyclooxygenase-2 (COX-2) is an enzyme that plays a pivotal role in peripheral inflammation and pain via the prostaglandin pathway. In the central nervous system (CNS), COX-2 is implicated in neurodegenerative and psychiatric disorders as a potential therapeutic target and biomarker. However, clinical studies with COX-2 have yielded inconsistent results, partly due to limited mechanistic understanding of how COX-2 activity relates to CNS pathology. Therefore, developing COX-2 positron emission tomography (PET) radiotracers for human neuroimaging is of interest. This study introduces [11C]BRD1158, which is a potent and uniquely fast-binding, selective COX-2 PET radiotracer. [11C]BRD1158 was developed by prioritizing potency at COX-2, isoform selectivity over COX-1, fast binding kinetics, and free fraction in the brain. Evaluated through in vivo PET neuroimaging in rodent models with human COX-2 overexpression, [11C]BRD1158 demonstrated high brain uptake, fast target-engagement, functional reversibility, and excellent specific binding, which is advantageous for human imaging applications. Lastly, post-mortem samples from Huntington's disease (HD) patients and preclinical HD mouse models showed that COX-2 levels were elevated specifically in disease-affected brain regions, primarily from increased expression in microglia. These findings indicate that COX-2 holds promise as a novel clinical marker of HD onset and progression, one of many potential applications of [11C]BRD1158 human PET.

Screening of Active Substances Regulating Alzheimer's Disease in Ginger and Visualization of the Effectiveness on 6-Gingerol Pathway Targets

Ginger has been reported to potentially treat Alzheimer's disease (AD), but the specific compounds responsible for this biological function and their mechanisms are still unknown. In this study, a combination of network pharmacology, molecular docking, and dynamic simulation technology was used to screen active substances that regulate AD and explore their mechanisms. The TCMSP, GeneCards, OMIM, and DisGeNET databases were utilized to obtain 95 cross-targets related to ginger's active ingredients and AD as key targets. A functional enrichment analysis revealed that the pathways in which ginger's active substances may be involved in regulating AD include response to exogenous stimuli, response to oxidative stress, response to toxic substances, and lipid metabolism, among others. Furthermore, a drug-active ingredient-key target interaction network diagram was constructed, highlighting that 6-Gingerol is associated with 16 key targets. Additionally, a protein-protein interaction (PPI) network was mapped for the key targets, and HUB genes (ALB, ACTB, GAPDH, CASP3, and CAT) were identified. Based on the results of network pharmacology and cell experiments, 6-Gingerol was selected as the active ingredient for further investigation. Molecular docking was performed between 6-Gingerol and its 16 key targets, and the top three proteins with the strongest binding affinities (ACHE, MMP2, and PTGS2) were chosen for molecular dynamics analysis together with the CASP3 protein as the HUB gene. The findings indicate that 6-Gingerol exhibits strong binding ability to these disease targets, suggesting its potential role in regulating AD at the molecular level, as well as in abnormal cholinesterase metabolism and cell apoptosis, among other related regulatory pathways. These results provide a solid theoretical foundation for future in vitro experiments using actual cells and animal experiments to further investigate the application of 6-Gingerol.

Quantification of COX-2 Level in Alzheimer's Disease Patients to Develop Potential Blood-Based Biomarker for Early Diagnosis and Therapeutic Target

Background

Alzheimer's disease (AD) is a progressive neurodegenerative disease and symptoms develop gradually over many years. The current direction for medication development in AD is focused on neuro-inflammation and oxidative stress. Amyloid-β (Aβ) deposition activates microglia leading to neuro-inflammation and neurodegeneration induced by activation of COX-2 via NFκB p50 in glioblastoma cells.

Objective

The study aimed to evaluate the concentration of COX-2 and NFκB p50 in serum of AD, mild cognitive impairment (MCI), and geriatric control (GC) and to establish a blood-based biomarker for early diagnosis and its therapeutic implications.

Methods

Proteins and their mRNA level in blood of study groups were measured by surface plasmon resonance (SPR) and quantitative polymerase chain reaction (qPCR), respectively. The level of protein was further validated by western blot. The binding study of designed peptide against COX-2 by molecular docking was verified by SPR. The rescue of neurotoxicity by peptide was also checked by MTT assay on SH-SY5Y cells (neuroblastoma cell line).

Results

Proteins and mRNA were highly expressed in AD and MCI compared to GC. However, COX-2 decreases with disease duration. The peptide showed binding affinity with COX-2 with low dissociation constant in SPR and rescued the neurotoxicity of SH-SY5Y cells by decreasing the level of Aβ, tau, and pTau proteins.

Conclusions

It can be concluded that COX-2 protein can serve as a potential blood-based biomarker for early detection and can be a good platform for therapeutic intervention for AD.

Prostaglandins in the Inflamed Central Nervous System: Potential Therapeutic Targets

The global burden of neurological disorders is evident, yet there remains limited efficacious therapeutics for their treatment. There is a growing recognition of the role of inflammation in diseases of the central nervous system (CNS); among the numerous inflammatory mediators involved, prostaglandins play a crucial role. Prostaglandins are small lipid mediators derived from arachidonic acid via multi-enzymatic pathways. The actions of prostaglandins are varied, with each prostaglandin having a specific role in maintaining homeostasis. In the CNS, prostaglandins can have neuroprotective or neurotoxic properties depending on their specific G-protein receptor. These G-protein receptors have varying subfamilies, tissue distribution, and signal transduction cascades. Further studies into the impact of prostaglandins in CNS-based diseases may contribute to the clarification of their actions, hopefully leading to the development of efficacious therapeutic strategies. This review focuses on the roles played by prostaglandins in neural degeneration, with a focus on Alzheimer's Disease, Multiple Sclerosis, and Amyotrophic Lateral Sclerosis in both preclinical and clinical settings. We further discuss current prostaglandin-related agonists and antagonists concerning suggestions for their use as future therapeutics.

Pleiotropic Potential of Evernia prunastri Extracts and Their Main Compounds Evernic Acid and Atranorin: In Vitro and In Silico Studies

Evernia prunastri is a lichen widely distributed in the Northern Hemisphere. Its biological properties still need to be discovered. Therefore, our paper focuses on studies of E. prunastri extracts, including its main metabolites evernic acid (EA) or atranorin (ATR). Phytochemical profiles using chromatographic analysis were confirmed. The antioxidant activity was evaluated using in vitro chemical tests and in vitro enzymatic cells-free tests, namely superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), and catalase (CAT). The anti-inflammatory potential using cyclooxygenase-2 (COX-2) and hyaluronidase were determined. The neuroprotective potential using acetylcholinesterase, (AChE), butyrylcholinesterase (BChE), and tyrosinase (Tyr) was estimated. The hypoglycemic activity was also confirmed (α-glucosidase). Principal component analysis was performed to determine the relationship between the biological activity of extracts. The inhibitory effect of EA and ATR on COX-2 AChE, BChE, Tyr, and α-glucosidase was evaluated using molecular docking techniques and confirmed for EA and ATR (besides α-glucosidase). The penetration of EA and ATR from extracts through the blood-brain barrier was confirmed using the parallel artificial membrane permeability assay blood-brain barrier test. In conclusion, depending on chemical surroundings and the concentration, the E. prunastri extracts, EA or ATR, showed attractive pleiotropic properties, which should be further investigated.

Bisphenol A induced neuronal apoptosis and enhanced autophagy in vitro through Nrf2/HO-1 and Akt/mTOR pathways

Bisphenol A (BPA) was traditionally used in epoxy resins and polycarbonate plastics, but it was found to be harmful to human health due to its endocrine-disrupting effects. It can affect various biological functions of human beings and interfere with brain development. However, the neurotoxic mechanisms of BPA on brain development and associated neurodegeneration remain poorly understood. Here, we reported that BPA (100, 250, 500 μM) inhibited cell viability of neural cells PC12, SH-SY5Y and caused dose-dependent cell death. In addition, BPA exposure increased intracellular reactive oxygen species (ROS) and mitochondrial ROS (mtROS) levels, decreased mitochondrial membrane potential, reduced the expression of cytochrome c oxidase IV (COX4), downregulated Bcl-2, and initiated apoptosis. Moreover, BPA treatment resulted in the accumulation of intracellular acidic vacuoles and increased the autophagy marker LC3 II to LC3 I ratio. Furthermore, BPA exposure inhibited Nrf2/ HO-1 and AKT/mTOR pathways and mediated cellular oxidative stress, apoptosis, and excessive autophagy, leading to neuronal degeneration. The interactions between oxidative stress, autophagy, and apoptosis during BPA-induced neurotoxicity remain unclear and require further in vivo confirmation.

Exploring the role of COX-2 in Alzheimer's disease: Potential therapeutic implications of COX-2 inhibitors

This review highlights the potential role of cyclooxygenase-2 enzyme (COX-2) in the pathogenesis of Alzheimer's disease (AD) and the potential therapeutic use of non-steroidal anti-inflammatory drugs (NSAIDs) in the management of AD. In addition to COX-2 enzymes role in inflammation, the formation of amyloid plaques and neurofibrillary tangles in the brain, the review emphasizes that COXs-2 have a crucial role in normal synaptic activity and plasticity, and have a relationship with acetylcholine, tau protein, and beta-amyloid (Aβ) which are the main causes of Alzheimer's disease. Furthermore, the review points out that COX-2 enzymes have a relationship with kinase enzymes, including Cyclin Dependent Kinase 5 (CDK5) and Glycogen Synthase Kinase 3β (GSK3β), which are known to play a role in tau phosphorylation and are strongly associated with Alzheimer's disease. Therefore, the use of drugs like NSAIDs may be a hopeful approach for managing AD. However, results from studies examining the effectiveness of NSAIDs in treating AD have been mixed and further research is needed to fully understand the mechanisms by which COX-2 and NSAIDs may be involved in the development and progression of AD and to identify new therapeutic strategies.

Potential drugs for the treatment of Alzheimer's disease

It is well known that amyloid precursor protein (APP), the enzyme β-secretase 1 (BACE1), cyclooxygenase 2 (COX-2), nicastrin (NCT), and hyperphosphorylated tau protein (p-tau) are closely related to the development of Alzheimer's disease (AD). In addition, recent evidence shows that neuroinflammation also contributes to the pathogenesis of AD. Although the mechanism is not clearly known, such inflammation could alter the activity of the aforementioned molecules. Therefore, the use of anti-inflammatory agents could slow the progression of the disease. Nimesulide, resveratrol, and citalopram are three anti-inflammatory agents that could contribute to a decrease in neuroinflammation and consequently to a decrease in the overexpression of APP, BACE1, COX-2, NCT, and p-Tau, as they possess anti-inflammatory effects that could regulate the expression of APP, BACE1, COX-2, NCT, and p-Tau of potent pro-inflammatory markers indirectly involved in the expression of APP, BACE1, NCT, COX-2, and p-Tau; therefore, their use could be beneficial as preventive treatment as well as in the early stages of AD.

Glial-derived Neuroinflammation induced with Amyloid-beta-peptide Plus Fibrinogen Injection in Rat Hippocampus

INTRODUCTION

The present study has examined microglial and astrocyte activation in association with neuronal degeneration in an animal model using an injection of amyloid-beta peptide Aβ1-42 (Aβ42) plus fibrinogen into rat hippocampus.

METHODS

The combination of stimuli is suggested as a novel and potent perturbation to induce gliosis and the production of glial-derived neurotoxic factors in an animal model exhibiting a leaky BBB (blood-brain barrier). Specifically, Aβ42 + fibrinogen stimulation elevated levels of COX-2 (cyclooxygenase-2) and iNOS (inducible nitric oxide synthase) with a considerable extent of neuronal loss associated with microglia and astrocyte activation.

RESULTS

Treatment of injected rats with the broad spectrum anti-inflammatory agent, minocycline or the iNOS inhibitor, 1400 W inhibited gliosis, reduced levels of COX-2 and iNOS, and demonstrated efficacy for neuroprotection.

CONCLUSION

The findings suggest the utility of combining amyloid beta peptide plus fibrinogen as a potent and understudied neuroinflammatory stimulus for the induction of glial-derived neurotoxic factors in BBB-compromised AD brain.

Clinical Biomarkers and Novel Drug Targets to Cut Gordian Knots of Alzheimer's Disease

BACKGROUND

Alzheimer's disease (AD), the primary cause of dementia, escalating worldwide, has no proper diagnosis or effective treatment. Neuronal cell death and impairment of cognitive abilities, possibly triggered by several brain mechanisms, are the most significant characteristic of this disorder.

METHODS

A multitude of pharmacological targets have been identified for potential drug design against AD. Although many advances in treatment strategies have been made to correct various abnormalities, these often exhibit limited clinical significance because this disease aggressively progresses into different regions of the brain, causing severe deterioration.

RESULTS

These biomarkers can be game-changers for early detection and timely monitoring of such disorders.

CONCLUSION

This review covers clinically significant biomarkers of AD for precise and early monitoring of risk factors and stages of this disease, the potential site of action and novel targets for drugs, and pharmacological approaches to clinical management.

Exploring the common pathogenesis of Alzheimer's disease and type 2 diabetes mellitus via microarray data analysis

Background

Alzheimer's Disease (AD) and Type 2 Diabetes Mellitus (DM) have an increased incidence in modern society. Although more and more evidence has supported that DM is prone to AD, the interrelational mechanisms remain fully elucidated.

Purpose

The primary purpose of this study is to explore the shared pathophysiological mechanisms of AD and DM.

Methods

Download the expression matrix of AD and DM from the Gene Expression Omnibus (GEO) database with sequence numbers GSE97760 and GSE95849, respectively. The common differentially expressed genes (DEGs) were identified by limma package analysis. Then we analyzed the six kinds of module analysis: gene functional annotation, protein-protein interaction (PPI) network, potential drug screening, immune cell infiltration, hub genes identification and validation, and prediction of transcription factors (TFs).

Results

The subsequent analyses included 339 common DEGs, and the importance of immunity, hormone, cytokines, neurotransmitters, and insulin in these diseases was underscored by functional analysis. In addition, serotonergic synapse, ovarian steroidogenesis, estrogen signaling pathway, and regulation of lipolysis are closely related to both. DEGs were input into the CMap database to screen small molecule compounds with the potential to reverse AD and DM pathological functions. L-690488, exemestane, and BMS-345541 ranked top three among the screened small molecule compounds. Finally, 10 essential hub genes were identified using cytoHubba, including PTGS2, RAB10, LRRK2, SOS1, EEA1, NF1, RAB14, ADCY5, RAPGEF3, and PRKACG. For the characteristic Aβ and Tau pathology of AD, RAPGEF3 was associated significantly positively with AD and NF1 significantly negatively with AD. In addition, we also found ADCY5 and NF1 significant correlations with DM phenotypes. Other datasets verified that NF1, RAB14, ADCY5, and RAPGEF3 could be used as key markers of DM complicated with AD. Meanwhile, the immune cell infiltration score reflects the different cellular immune microenvironments of the two diseases.

Conclusion

The common pathogenesis of AD and DM was revealed in our research. These common pathways and hub genes directions for further exploration of the pathogenesis or treatment of these two diseases.

Arc Regulates Transcription of Genes for Plasticity, Excitability and Alzheimer’s Disease

The immediate early gene Arc is a master regulator of synaptic function and a critical determinant of memory consolidation. Here, we show that Arc interacts with dynamic chromatin and closely associates with histone markers for active enhancers and transcription in cultured rat hippocampal neurons. Both these histone modifications, H3K27Ac and H3K9Ac, have recently been shown to be upregulated in late-onset Alzheimer’s disease (AD). When Arc induction by pharmacological network activation was prevented using a short hairpin RNA, the expression profile was altered for over 1900 genes, which included genes associated with synaptic function, neuronal plasticity, intrinsic excitability, and signalling pathways. Interestingly, about 100 Arc-dependent genes are associated with the pathophysiology of AD. When endogenous Arc expression was induced in HEK293T cells, the transcription of many neuronal genes was increased, suggesting that Arc can control expression in the absence of activated signalling pathways. Taken together, these data establish Arc as a master regulator of neuronal activity-dependent gene expression and suggest that it plays a significant role in the pathophysiology of AD.

γ-mangostin attenuates amyloid-β42-induced neuroinflammation and oxidative stress in microglia-like BV2 cells via the mitogen-activated protein kinases signaling pathway

BACKGROUND

Oxidative stress (OS) and neuroinflammation are related to the pathogenic mechanism of Alzheimer's disease (AD). γ-Mangostin, a xanthone derivative obtained from mangosteen pericarp, could prevent their detrimental effects in AD.

OBJECTIVE

This study focused on determining the role of γ-mangostin in protection against the amyloid-β (Aβ) 42 oligomers-induced OS and inflammation in microglial BV2 cells and investigating their precise mechanism of action.

METHODS

Lactate dehydrogenase release assay and cell counting kit-8 assay were used to estimate the drug impact in BV2 cells and functional effects of the conditioned medium (supernatant of Aβ42 oligomers-/γ-mangostin-treated BV2 cells) on neuron-like SH-SY5Y and N2a cells. Quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay were carried out for detecting inflammatory factor contents. In addition, nitric oxide (NO) assay, an intracellular reactive oxygen species (ROS) assay, and qRT-PCR were performed to measure OS. Western blotting was used to explore the influence of γ-mangostin on the mitogen-activated protein kinase (MAPK) pathway.

RESULTS

γ-Mangostin alleviated Aβ42 oligomer-induced inflammation by decreasing the levels of interleukin (IL) -6, IL-1β, and tumor necrosis factor-α, while attenuating OS through decreasing ROS/NO generation, and suppressing cyclo-oxygenase-2 and inducible NO synthase expressions. γ-Mangostin protected N2a and SH-SY5Ycells against the BV2 cell supernatant-induced toxicity following Aβ42 oligomer exposure. Furthermore, γ-mangostin inhibited c-Jun NH2-terminal kinase and p38 MAPK pathway activation.

CONCLUSION

This study demonstrated that γ-mangostin could attenuate OS and inflammation resulting from Aβ42 oligomers, which also protect neurons against toxic medium-induced injury, suggesting that it may exert a protective effect in AD.

SARS-CoV-2 Exacerbates Beta-Amyloid Neurotoxicity, Inflammation and Oxidative Stress in Alzheimer's Disease Patients

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) triggered the pandemic Coronavirus Disease 19 (COVID-19), causing millions of deaths. The elderly and those already living with comorbidity are likely to die after SARS-CoV-2 infection. People suffering from Alzheimer’s disease (AD) have a higher risk of becoming infected, because they cannot easily follow health roles. Additionally, those suffering from dementia have a 40% higher risk of dying from COVID-19. Herein, we collected from Gene Expression Omnibus repository the brain samples of AD patients who died of COVID-19 (AD+COVID-19), AD without COVID-19 (AD), COVID-19 without AD (COVID-19) and control individuals. We inspected the transcriptomic and interactomic profiles by comparing the COVID-19 cohort against the control cohort and the AD cohort against the AD+COVID-19 cohort. SARS-CoV-2 in patients without AD mainly activated processes related to immune response and cell cycle. Conversely, 21 key nodes in the interactome are deregulated in AD. Interestingly, some of them are linked to beta-amyloid production and clearance. Thus, we inspected their role, along with their interactors, using the gene ontologies of the biological process that reveals their contribution in brain organization, immune response, oxidative stress and viral replication. We conclude that SARS-CoV-2 worsens the AD condition by increasing neurotoxicity, due to higher levels of beta-amyloid, inflammation and oxidative stress.

Modulation of Neuro-Inflammatory Signals in Microglia by Plasma Prekallikrein and Neuronal Cell Debris

Microglia, the resident phagocytes of the central nervous system and one of the key modulators of the innate immune system, have been shown to play a major role in brain insults. Upon activation in response to neuroinflammation, microglia promote the release of inflammatory mediators as well as promote phagocytosis. Plasma prekallikrein (PKall) has been recently implicated as a mediator of neuroinflammation; nevertheless, its role in mediating microglial activation has not been investigated yet. In the current study, we evaluate the mechanisms through which PKall contributes to microglial activation and release of inflammatory cytokines assessing PKall-related receptors and their dynamics. Murine N9-microglial cells were exposed to PKall (2.5 ng/ml), lipopolysaccharide (100 ng/ml), bradykinin (BK, 0.1 μM), and neuronal cell debris (16.5 μg protein/ml). Gene expression of bradykinin 2 receptor (B₂KR), protease-activated receptor 2 (PAR-2), along with cytokines and fibrotic mediators were studied. Bioinformatic analysis was conducted to correlate altered protein changes with microglial activation. To assess receptor dynamics, HOE-140 (1 μM) and GB-83 (2 μM) were used to antagonize the B₂KR and PAR-2 receptors, respectively. Also, the role of autophagy in modulating microglial response was evaluated. Data from our work indicate that PKall, LPS, BK, and neuronal cell debris resulted in the activation of microglia and enhanced expression/secretion of inflammatory mediators. Elevated increase in inflammatory mediators was attenuated in the presence of HOE-140 and GB-83, implicating the engagement of these receptors in the activation process coupled with an increase in the expression of B₂KR and PAR-2. Finally, the inhibition of autophagy significantly enhanced the release of the cytokine IL-6 which were validated via bioinformatics analysis demonstrating the role of PKall in systematic and brain inflammatory processes. Taken together, we demonstrated that PKall can modulate microglial activation via the engagement of PAR-2 and B₂KR where PKall acts as a neuromodulator of inflammatory processes.

The Upregulation of COX2 in Human Degenerated Nucleus Pulposus: The Association of Inflammation with Intervertebral Disc Degeneration

Intervertebral disc degeneration (IVDD) is an important risk factor of low back pain. We previously found upregulated markers of fibrosis, the late stage of chronic inflammation, in degenerated IVD with a small number of clinical specimens. Here, we aimed to study on a larger scale the association of cyclooxygenase 2 (COX2), an inflammation and/or pain marker, with IVDD. This study involved 107 LBP participants. The IVD degeneration level was graded on a 1–5 scale according to the Pfirrmann classification system. Discs at grades 1-3 were further grouped as white discs with grades 4-5 as black discs. We recorded baseline information about age, gender, body mass index (BMI), diabetes history, smoking history, and magnetic resonance imaging (MRI). Their association with IVDD was statistically analyzed. The expression level of COX2 was investigated by immunohistochemistry. The total integrated COX2 optical density (IOD), number of COX2-positive cells, and total cell number of each image were counted and analyzed by Image-Pro Plus software. The IOD and number of COX2-positive cells were divided by the total cell number to obtain COX2 expression density (IOD/cell) and COX2 positivity (cell+/cell). As a result, among the baseline information investigated, only age was found to have a significant association with IVDD. The IOD/cell was found to be significantly increased from grade 2 to grade 5, as well as in black discs compared to white discs. The cell+/cell displayed the same trend that it increased in highly degenerative discs compared to their counterparts. In conclusion, the expression of COX2 is associated with IVDD, which highlights COX2 as a biomarker for IVD degeneration and indicates the involvement of inflammation and pain signaling in IVDD.

Neuroinflammation in neurological disorders: pharmacotherapeutic targets from bench to bedside

Neuroinflammation is one of the host defensive mechanisms through which the nervous system protects itself from pathogenic and or infectious insults. Moreover, neuroinflammation occurs as one of the most common pathological outcomes in various neurological disorders, makes it the promising target. The present review focuses on elaborating the recent advancement in understanding molecular mechanisms of neuroinflammation and its role in the etiopathogenesis of various neurological disorders, especially Alzheimer's disease (AD), Parkinson's disease (PD), and Epilepsy. Furthermore, the current status of anti-inflammatory agents in neurological diseases has been summarized in light of different preclinical and clinical studies. Finally, possible limitations and future directions for the effective use of anti-inflammatory agents in neurological disorders have been discussed.

Systemic inflammation induced changes in protein expression of ABC transporters and ionotropic glutamate receptor subunit 1 in the cerebral cortex of familial Alzheimer`s disease mouse model

Alzheimer's disease (AD) is an incurable disease, with complex pathophysiology and a myriad of proteins involved in its development. In this study, we applied quantitative targeted absolute proteomic analysis for investigation of changes in potential AD drug targets, biomarkers, and transporters in cerebral cortices of lipopolysaccharide (LPS)-induced neuroinflammation mouse model, familial AD mice (APdE9) with and without LPS treatment as compared to age-matched wild type (WT) mice. The ABCB1, ABCG2 and GluN1 protein expression ratios between LPS treated APdE9 and WT control mice were 0.58 (95% CI 0.44 - 0.72), 0.65 (95% CI 0.53 - 0.77) and 0.61 (95% CI 0.52 - 0.69), respectively. The protein expression levels of other proteins such as MGLL, COX-2, CytC, ABCC1, ABCC4, SLC2A1 and SLC7A5 did not differ between the study groups. Overall, the study revealed that systemic inflammation can alter ABCB1 and ABCG2 protein expression in brain in AD, which can affect intra-brain drug distribution and play a role in AD development. Moreover, the inflammatory insult caused by peripheral infection in AD may be important factor triggering changes in GluN1 protein expression. However, more studies need to be performed in order to confirm these findings. The quantitative information about the expression of selected proteins provides important knowledge, which may help in the optimal use of the mouse models in AD drug development and better translation of preclinical data to humans.

Indomethacin Disrupts the Formation of β-Amyloid Plaques via an α2-Macroglobulin-Activating lrp1-Dependent Mechanism

Epidemiological studies have implied that the nonsteroidal anti-inflammatory drug (NSAID) indomethacin slows the development and progression of Alzheimer’s disease (AD). However, the underlying mechanisms are notably understudied. Using a chimeric mouse/human amyloid precursor protein (Mo/HuAPP695swe) and a mutant human presenilin 1 (PS1-dE9) (APP/PS1) expressing transgenic (Tg) mice and neuroblastoma (N) 2a cells as in vivo and in vitro models, we revealed the mechanisms of indomethacin in ameliorating the cognitive decline of AD. By screening AD-associated genes, we observed that a marked increase in the expression of α₂-macroglobulin (A2M) was markedly induced after treatment with indomethacin. Mechanistically, upregulation of A2M was caused by the inhibition of cyclooxygenase-2 (COX-2) and lipocalin-type prostaglandin D synthase (L-PGDS), which are responsible for the synthesis of prostaglandin (PG)H₂ and PGD₂, respectively. The reduction in PGD₂ levels induced by indomethacin alleviated the suppression of A2M expression through a PGD₂ receptor 2 (CRTH2)-dependent mechanism. Highly activated A2M not only disrupted the production and aggregation of β-amyloid protein (Aβ) but also induced Aβ efflux from the brain. More interestingly, indomethacin decreased the degradation of the A2M receptor, low-density lipoprotein receptor-related protein 1 (LRP1), which facilitated the brain efflux of Aβ. Through the aforementioned mechanisms, indomethacin ameliorated cognitive decline in APP/PS1 Tg mice by decreasing Aβ production and clearing Aβ from the brains of AD mice.

Pine nut antioxidant peptides ameliorate the memory impairment in a scopolamine-induced mouse model via SIRT3-induced synaptic plasticity

This study aimed to investigate the effects of a pine nut albumin hydrolysate (fraction <3 kDa) and of its short peptide derivative, Trp-Tyr-Pro-Gly-Lys (WYPGK), on synaptic plasticity and memory function in scopolamine-induced memory-impaired mice, as well as the potential underlying mechanism in PC12 cells. In the scopolamine-induced mouse model, the results revealed that the fraction <3 kDa and WYPGK enhanced synaptic plasticity and improved learning and memory function. H&E and Nissl staining analysis showed that the damage in hippocampal neurons was decreased. Golgi staining and transmission electron microscopy further revealed that the enhanced synaptic plasticity was associated with increased dendritic spine abundance and synaptic density. In an H₂O₂-induced PC12 cell model, treatment with mitochondrial sirtuin 3 (SIRT3) inhibitor and inducer molecules confirmed that the <3 kDa fraction and WYPGK activated SIRT3, leading to the decrease in Ace-SOD2 acetylation and increasing the expression of SYP, SYN-1, SNAP25, and PSD95, thus enhancing synaptic plasticity. The <3 kDa fraction and WYPGK also activated the ERK/CREB pathway and upregulated the expression of brain-derived neurotrophic factor. Our results show that fraction <3 kDa and WYPGK improve learning and memory ability through SIRT3-induced synaptic plasticity in vitro and in vivo.

The Emerging Role of COX-2, 15-LOX and PPARγ in Metabolic Diseases and Cancer: An Introduction to Novel Multi-target Directed Ligands (MTDLs)

Emerging evidence supports an intertwining framework for the involvement of different inflammatory pathways in a common pathological background for a number of disorders. Of importance are pathways involving arachidonic acid metabolism by cyclooxygenase-2 (COX-2) and 15-lipoxygenase (15-LOX). Both enzyme activities and their products are implicated in a range of pathophysiological processes encompassing metabolic impairment leading to adipose inflammation and the subsequent vascular and neurological disorders, in addition to various pro- and antitumorigenic effects. A further layer of complexity is encountered by the disparate, and often reciprocal, modulatory effect COX-2 and 15-LOX activities and metabolites exert on each other or on other cellular targets, the most prominent of which is peroxisome proliferator-activated receptor gamma (PPARγ). Thus, effective therapeutic intervention with such multifaceted disorders requires the simultaneous modulation of more than one target. Here, we describe the role of COX-2, 15-LOX, and PPARγ in cancer and complications of metabolic disorders, highlight the value of designing multi-target directed ligands (MTDLs) modifying their activity, and summarizing the available literature regarding the rationale and feasibility of design and synthesis of these ligands together with their known biological effects. We speculate on the potential impact of MTDLs in these disorders as well as emphasize the need for structured future effort to translate these early results facilitating the adoption of these, and similar, molecules in clinical research.

Effect of Experimental Ischemic Stroke and PGE2 EP1 Selective Antagonism in Alzheimer's Disease Mouse Models

BACKGROUND

Neuroinflammation has been recognized as an important factor in the pathogenesis of Alzheimer's disease (AD). One of the most recognized pathways in mediating neuroinflammation is the prostaglandin E2-EP1 receptor pathway.

OBJECTIVE

Here, we examined the efficacy of the selective EP1 antagonist ONO-8713 in limiting amyloid-β (Aβ), lesion volumes, and behavioral indexes in AD mouse models after ischemic stroke.

METHODS

Transgenic APP/PS1, 3xTgAD, and wildtype (WT) mice were subjected to permanent distal middle cerebral artery occlusion (pdMCAO) and sham surgeries. Functional outcomes, memory, anatomical outcomes, and Aβ concentrations were assessed 14 days after surgery.

RESULTS

pdMCAO resulted in significant deterioration in functional and anatomical outcomes in the transgenic mice compared with the WT mice. No relevant differences were observed in the behavioral tests when comparing the ONO-8713 and vehicle-treated groups. Significantly lower cavitation (p = 0.0373) and percent tissue loss (p = 0.0247) were observed in APP/PS1 + ONO-8713 mice compared with the WT + ONO-8713 mice. However, the percent tissue injury was significantly higher in APP/PS1 + ONO-8713 mice compared with the WT + ONO-8713 group (p = 0.0373). Percent tissue loss was also significantly lower in the 3xTgAD + ONO-8713 mice than in the WT + ONO-8713 mice (p = 0.0185). ONO-8713 treatment also attenuated cortical microgliosis in APP/PS1 mice as compared with the vehicle (p = 0.0079); however, no differences were observed in astrogliosis across the groups. Finally, APP/PS1 mice presented with characteristic Aβ load in the cortex while 3xTgAD mice exhibited very low Aβ levels.

CONCLUSION

In conclusion, under the experimental conditions, EP1 receptor antagonist ONO-8713 showed modest benefits in anatomical outcomes after stroke, mainly in APP/PS1 mice.

Viral Involvement in Alzheimer's Disease

Alzheimer's disease (AD) is characterized by the presence of β-amyloid plaques (Aβ) and neurofibrillary tangles (NFTs) in the brain. The prevalence of the disease is increasing and is expected to reach 141 million cases by 2050. Despite the risk factors associated with the disease, there is no known causative agent for AD. Clinical trials with many drugs have failed over the years, and no therapeutic has been approved for AD. There is increasing evidence that pathogens are found in the brains of AD patients and controls, such as human herpes simplex virus-1 (HSV-1). Given the lack of a human model, the route for pathogen entry into the brain remains open for scrutiny and may include entry via a disturbed blood-brain barrier or the olfactory nasal route. Many factors can contribute to the pathogenicity of HSV-1, such as the ability of HSV-1 to remain latent, tau protein phosphorylation, increased accumulation of Aβ invivo and in vitro, and repeated cycle of reactivation if immunocompromised. Intriguingly, valacyclovir, a widely used drug for the treatment of HSV-1 and HSV-2 infection, has shown patient improvement in cognition compared to controls in AD clinical studies. We discuss the potential role of HSV-1 in AD pathogenesis and argue for further studies to investigate this relationship.

A review on α-mangostin as a potential multi-target-directed ligand for Alzheimer's disease

Alzheimer's disease (AD) is an age-related neurodegenerative disease characterized by progressive memory loss, declining language skills and other cognitive disorders. AD has brought great mental and economic burden to patients, families and society. However due to the complexity of AD's pathology, drugs developed for the treatment of AD often fail in clinical or experimental trials. The main problems of current anti-AD drugs are low efficacy due to mono-target method or side effects, especially high hepatotoxicity. To tackle these two main problems, multi-target-directed ligand (MTDL) based on "one molecule, multiple targets" has been studied. MTDLs can regulate multiple biological targets at the same time, so it has shown higher efficacy, better safety. As a natural active small molecule, α-mangostin (α-M) has shown potential multi-factor anti-AD activities in a series of studies, furthermore it also has a certain hepatoprotective effect. The good availability of α-M also provides support for its application in clinical research. In this work, multiple activities of α-M related to AD therapy were reviewed, which included anti-cholinesterase, anti-amyloid-cascade, anti-inflammation, anti-oxidative stress, low toxicity, hepatoprotective effects and drug formulation. It shows that α-M is a promising candidate for the treatment of AD.

Isoliquiritigenin Confers Neuroprotection and Alleviates Amyloid-β42-Induced Neuroinflammation in Microglia by Regulating the Nrf2/NF-κB Signaling

Background

Neuroinflammation and oxidative stress are two major pathological characteristics of Alzheimer's disease (AD). Amyloid-β oligomers (AβO), a toxic form of Aβ, promote the neuroinflammation and oxidative stress in the development of AD. Isoliquiritigenin (ISL), a natural flavonoid isolated from the root of liquorice, has been shown to exert inhibitory effects on inflammatory response and oxidative stress.

Objectives

The main purpose of this study is to assess the influence of ISL on inflammatory response and oxidative stress in BV2 cells stimulated with AβO, and to explore the underlying molecular mechanisms.

Methods

3-(4,5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H- tetrazolium bromide (MTT) and lactate dehydrogenase (LDH) cytotoxicity assays were used to assess the toxic or protective effects of ISL. The expression levels of interleukin-1β, interleukin-6, and tumor necrosis factor-α were assessed by quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assays. Morphological changes in BV2 cells were assessed by immunofluorescence method. Nitric oxide (NO) assay kit was used to determinate the NO production. Western blot, qRT-PCR and immunofluorescence were used to explore the underlying molecular mechanisms.

Results

ISL treatment reduced the production of inflammatory cytokines and NO, and alleviated the morphological changes in BV2 cells induced by AβO. ISL treatment further protected N2a cells from the toxic medium of AβO-stimulated BV2 cells. ISL activated nuclear factor erythroid-2 related factor 2 (Nrf2) signaling and suppressed nuclear factor-κB (NF-κB) signaling in BV2 cells.

Conclusion

ISL suppresses AβO-induced inflammation and oxidative stress in BV2 cells via the regulation of Nrf2/NF-κB signaling. Therefore, ISL indirectly protects neurons from the damage of toxic conditioned media.

The Link between Exercise and Homocysteine in the Alzheimer's Disease: A Bioinformatic Network Model

Elevated peripheral expression of homocysteine (Hcy) is associated with an increased risk of coronary heart disease and stroke, diabetes, and cancer. It is also associated with cognitive impairment as it has been reported that high levels of Hcy cause cognitive dysfunction and memory deficit. Among several etiological factors that contribute to the pathogenesis of neurodegenerative diseases, including Alzheimer's disease (AD), Hcy seems to directly contribute to the generation of neurotoxicity factors. This study aims to hypothesize the molecular mechanism by which exercise can reduce the risk of neurological complications promoted by hyperhomocysteinemia (HHcy), and discuss how exercise could reduce the risk of developing AD by using bioinformatics network models. According to the genes network, there are connections between proteins and amino acids associated with Hcy, exercise, and AD. Studies have evidenced that exercise may be one of several processes by which acid nitric availability can be maximized in the human body, which is particularly important in reducing cell loss and tau pathology and, thereby, leading to a reduced risk of complications associated with HHcy and AD.

Drug repositioning as a therapeutic strategy for neurodegenerations associated with OPA1 mutations

OPA1 mutations are the major cause of dominant optic atrophy (DOA) and the syndromic form DOA plus, pathologies for which there is no established cure. We used a ‘drug repurposing’ approach to identify FDA-approved molecules able to rescue the mitochondrial dysfunctions induced by OPA1 mutations. We screened two different chemical libraries by using two yeast strains carrying the mgm1^I322M and the chim3^P646L mutations, identifying 26 drugs able to rescue their oxidative growth phenotype. Six of them, able to reduce the mitochondrial DNA instability in yeast, have been then tested in Opa1 deleted mouse embryonic fibroblasts expressing the human OPA1 isoform 1 bearing the R445H and D603H mutations. Some of these molecules were able to ameliorate the energetic functions and/or the mitochondrial network morphology, depending on the type of OPA1 mutation. The final validation has been performed in patients’ fibroblasts, allowing to select the most effective molecules. Our current results are instrumental to rapidly translating the findings of this drug repurposing approach into clinical trial for DOA and other neurodegenerations caused by OPA1 mutations.

Prostaglandin A1 Decreases the Phosphorylation of Tau by Activating Protein Phosphatase 2A via a Michael Addition Mechanism at Cysteine 377

Prostaglandin (PG) A1 is a metabolic product of cyclooxygenase 2 (COX-2) that is potentially involved in regulating the development and progression of Alzheimer's disease (AD). PGA1 is a cyclopentenone (cy) PG characterized by the presence of a chemically reactive α,β-unsaturated carbonyl. PGA1 is potentially involved in the regulation of multiple biological processes via Michael addition; however, the specific roles of PGA1 in AD remain unclear. Tau^P301S transgenic (Tg) mice were used as in vivo AD models, and neuroblastoma (N) 2a cells were used as an in vitro neuronal model. The PGA1-binding proteins were identified by HPLC-MS-MS after intracerebroventricular injection (i.c.v) of PGA1. Western blotting was used to determine tau phosphorylation in PGA1-treated Tg mice in the absence or in the presence of okadaic acid (OA), an inhibitor of protein phosphatase (PP) 2A. A combination of pull-down assay, immunoprecipitation, western blotting, and HPLC-MS-MS was used to determine that the PP2A scaffold subunit A alpha (PPP2R1A) is activated by the direct binding of PGA1 to cysteine 377. The effect of inhibiting tau hyperphosphorylation was tested in the Morris maze to determine the inhibitory effects of PGA1 on cognitive decline in tau^P301S Tg mice. Incubation with N2a cells, pull-down assay, and mass spectrometry (MS) analysis revealed and indicated that PGA1 binds to more than 1000 proteins; some of these proteins are associated with AD and especially with tauopathies. Moreover, short-term administration of PGA1 in tau^P301S Tg mice significantly decreased tau phosphorylation at Thr181, Ser202, and Ser404 in a dose-dependent manner. This effect was caused by the activation of PPP2R1A in tau^P301S Tg mice. Importantly, PGA1 can form a Michael adduct with cysteine 377 of PPP2R1A, which is critical for the enzymatic activity of PP2A. Long-term treatment of tau^P301S Tg mice with PGA1 activated PP2A and significantly reduced tau phosphorylation resulting in improvements in cognitive decline in tau^P301S Tg mice. Our data provided new insight into the mechanisms of the ameliorating effects of PGA1 on cognitive decline in tau^P301S Tg mice by activating PP2A via a mechanism involving the formation of a Michael adduct with cysteine 377 of PPP2R1A.

Inhibition of the prostaglandin EP2 receptor prevents long-term cognitive impairment in a model of systemic inflammation

Long-term cognitive and affective impairments are common problems in the survivors of sepsis, which weakens their vocational and daily life ability. Neuroinflammation has been reported to exert a key role in the development of cognitive deficit in different disorders including epilepsy, Alzheimer's disease (AD) and stroke. Mice treated with lipopolysaccharide (LPS), an endotoxin produced by gram-negative bacteria, show a robust but short-lived neuroinflammation and develop long-term memory and affective problems. In this study, we test the hypothesis that pharmacological blockade of the EP2 receptor for prostaglandin E2 reduces neuroinflammation and prevents long-term affective and memory deficits in a mouse model of LPS-induced, sepsis-associated encephalopathy (SAE). Our results show that an EP2 antagonist, TG6-10-1, promotes the recovery of body weight, mitigates neuroinflammation as judged by inflammatory cytokines and microgliosis, prevents the loss of synaptic proteins, and ameliorates depression-like behavior in the sucrose preference test as well as memory loss in the novel object recognition test. Our results point to a new avenue to ameliorate neuroinflammation and long-term affective and cognition problems of sepsis survivors.

International Union of Basic and Clinical Pharmacology. CIX. Differences and Similarities between Human and Rodent Prostaglandin E2 Receptors (EP1-4) and Prostacyclin Receptor (IP): Specific Roles in Pathophysiologic Conditions

Prostaglandins are derived from arachidonic acid metabolism through cyclooxygenase activities. Among prostaglandins (PGs), prostacyclin (PGI2) and PGE2 are strongly involved in the regulation of homeostasis and main physiologic functions. In addition, the synthesis of these two prostaglandins is significantly increased during inflammation. PGI2 and PGE2 exert their biologic actions by binding to their respective receptors, namely prostacyclin receptor (IP) and prostaglandin E2 receptor (EP) 1-4, which belong to the family of G-protein-coupled receptors. IP and EP1-4 receptors are widely distributed in the body and thus play various physiologic and pathophysiologic roles. In this review, we discuss the recent advances in studies using pharmacological approaches, genetically modified animals, and genome-wide association studies regarding the roles of IP and EP1-4 receptors in the immune, cardiovascular, nervous, gastrointestinal, respiratory, genitourinary, and musculoskeletal systems. In particular, we highlight similarities and differences between human and rodents in terms of the specific roles of IP and EP1-4 receptors and their downstream signaling pathways, functions, and activities for each biologic system. We also highlight the potential novel therapeutic benefit of targeting IP and EP1-4 receptors in several diseases based on the scientific advances, animal models, and human studies. SIGNIFICANCE STATEMENT: In this review, we present an update of the pathophysiologic role of the prostacyclin receptor, prostaglandin E2 receptor (EP) 1, EP2, EP3, and EP4 receptors when activated by the two main prostaglandins, namely prostacyclin and prostaglandin E2, produced during inflammatory conditions in human and rodents. In addition, this comparison of the published results in each tissue and/or pathology should facilitate the choice of the most appropriate model for the future studies.

A Network Pharmacological Approach to Investigate the Mechanism of Action of Active Ingredients of Epimedii Herba and Their Potential Targets in Treatment of Alzheimer's Disease

Background

Epimedii Herba is a traditional Chinese herbal medicine used to treat central nervous system diseases such as Alzheimer’s disease in China. However, the pharmacological mechanism is unclear. To investigate the mechanisms of Epimedii Herba in the treatment of Alzheimer’s disease, we assessed effective compounds, corresponding targets, and related pathways of Epimedii Herba in the treatment of Alzheimer’s disease based on network pharmacology.

Material/Methods

The active components and targets of Epimedii Herba were obtained through the TCMSP database and the DrugBank database. The DisGeNET database and GeneCards database were used to search for Alzheimer’s disease targets. The common targets of components and disease were obtained by Wayne diagram. Gene ontology (GO) analysis and enrichment analysis of the Kyoto Encyclopedia of Genes and Genomes (KEGG) were performed using the DAVID database. The component-target-pathway interaction network model was constructed using Cytoscape software. Auto Duck Vina software was used for molecular docking to analyze the affinity of the key ingredients and the main targets.

Results

We screened 17 active ingredients and 27 key targets of Epimedii Herba in the treatment of Alzheimer’s disease, which were related to the HIF-1 signaling pathway, TNF signaling pathway, PI3K-Akt signaling pathway, NF-κB signaling pathway, VEGF signaling pathway, and sphingolipid signaling pathway.

Conclusions

Based on network pharmacology, the multi-component, multi-target, and multi-pathway characteristics of Epimedii Herba in the treatment of Alzheimer’s disease were explored. Our results provide new ideas for future pharmacological and experimental research on Epimedii Herba in the treatment of Alzheimer’s disease.

The Role of Brain Cyclooxygenase-2 (Cox-2) Beyond Neuroinflammation: Neuronal Homeostasis in Memory and Anxiety

Cyclooxygenases are a group of heme-containing isozymes (namely Cox-1 and Cox-2) that catalyze the conversion of arachidonic acid to largely bioactive prostaglandins (PGs). Cox-1 is the ubiquitous housekeeping enzyme, and the mitogen-inducible Cox-2 is activated to cause inflammation. Interestingly, Cox-2 is constitutively expressed in the brain at the postsynaptic dendrites and excitatory terminals of the cortical and spinal cord neurons. Neuronal Cox-2 is activated in response to synaptic excitation to yield PGE₂, the predominant Cox-2 metabolite in the brain, which in turn stimulates the release of glutamate and neuronal firing in a retrograde fashion. Cox-2 is also engaged in the metabolism of new endocannabinoids from 2-arachidonoyl-glycerol to modulate their actions at presynaptic terminals. In addition to these interactions, the induction of neuronal Cox-2 is coupled to the trans-synaptic activation of the dopaminergic mesolimbic system and some serotoninergic receptors, which might contribute to the development of emotional behavior. Although much of the focus regarding the induction of Cox-2 in the brain has been centered on neuroinflammation-related neurodegenerative and psychiatric disorders, some evidence also suggests that Cox-2 release during neuronal signaling may be pivotal for the fine tuning of cortical networks to regulate behavior. This review compiles the evidence supporting the homeostatic role of neuronal Cox-2 in synaptic transmission and plasticity, since neuroinflammation is originally triggered by the induction of glial Cox-2 expression. The goal is to provide perspective on the roles of Cox-2 beyond neuroinflammation, such as those played in memory and anxiety, and whose evidence is still scant.

Radiosynthesis and evaluation of [18F]FMTP, a COX-2 PET ligand

BACKGROUND

The upregulation of cyclooxygenase-2 (COX-2) is involved in neuroinflammation associated with many neurological diseases as well as cancers of the brain. Outside the brain, inflammation and COX-2 induction contribute to the pathogenesis of pain, arthritis, acute allograft rejection, and in response to infections, tumors, autoimmune disorders, and injuries. Herein, we report the radiochemical synthesis and evaluation of [¹⁸F]6-fluoro-2-(4-(methylsulfonyl)phenyl)-N-(thiophen-2-ylmethyl)pyrimidin-4-amine ([¹⁸F]FMTP), a high-affinity COX-2 inhibitor, by cell uptake and PET imaging studies.

METHODS

The radiochemical synthesis of [¹⁸F]FMTP was optimized using chlorine to fluorine displacement method, by reacting [¹⁸F]fluoride/K222/K₂CO₃ with the precursor molecule. Cellular uptake studies of [¹⁸F]FMTP was performed in COX-2 positive BxPC3 and COX-2 negative PANC-1 cell lines with unlabeled FMTP as well as celecoxib to define specific binding agents. Dynamic microPET image acquisitionwas performed in anesthetized nude mice (n = 3), lipopolysaccharide (LPS) induced neuroinflammation mice (n = 4), and phosphate-buffered saline (PBS) administered control mice (n = 4) using a Trifoil microPET/CT for a scan period of 60 min.

RESULTS

A twofold higher binding of [¹⁸F]FMTP was found in COX-2 positive BxPC3 cells compared with COX-2 negative PANC-1 cells. The radioligand did not show specific binding to COX-2 negative PANC-1 cells. MicroPET imaging in wild-type mice indicated blood-brain barrier (BBB) penetration and fast washout of [¹⁸F]FMTP in the brain, likely due to the low constitutive COX-2 expression in the normal brain. In contrast, a ~ twofold higher uptake of the radioligand was found in LPS-induced mice brain than PBS treated control mice.

CONCLUSIONS

Specific binding to COX-2 in BxPC3 cell lines, BBB permeability, and increased brain uptake in neuroinflammation mice qualifies [¹⁸F]FMTP as a potential PET tracer for studying inflammation.

Effect of Novel Pyrrolo[3,4-d]pyridazinone Derivatives on Lipopolysaccharide-Induced Neuroinflammation

Neuroinflammation is considered to be one of the potential causes for the development of neurodegenerative diseases, including Alzheimer's disease. In this study, we evaluated the effect of four newly synthesized pyrrolo[3,4-d]pyridazinone derivatives on the neuron-like PC12 cells under simulated inflammation conditions by preincubation with lipopolysaccharide (LPS). Our novel derivatives are selective cyclooxygenase-2 (COX-2) inhibitors and have similar effects to nonsteroidal anti-inflammatory drugs (NSAIDs). We assessed viability (LDH assay), metabolic activity (MTT assay), DNA damage (number of double-strand breaks measured by fast halo assay), and the neuronal features of cells (average neurite length and neurite outgrowth measured spectrofluorimetrically). DCF-DA and Griess assays were also performed, which allowed determining the impact of the tested compounds on the level of oxygen free radicals and nitrites. LPS administration significantly negatively affected the results in all tests performed, and treatment with the tested derivatives in most cases significantly reduced this negative impact. Multiple-criteria decision analysis indicated that overall, the best results were observed for compounds 2a and 2b at a concentration of 10 µM. The new derivatives showed intense activity against free oxygen radicals and nitrites. Reduced reactive oxygen species level also correlated with a decrease in the number of DNA damage. The compounds improved neuronal features, such as neurite length and outgrowth, and they also increased cell viability and mitochondrial activity. Our results suggest that derivatives 2a and 2b may also act additionally on mechanisms other than 3a and 3b.

Tenuifolin Attenuates Amyloid-β42-Induced Neuroinflammation in Microglia Through the NF-κB Signaling Pathway

BACKGROUND

Inflammation and oxidative stress are believed to play an important role in the pathogenesis of Alzheimer's disease (AD). Tenuifolin (TEN) is a natural neuroprotective compound extracted from Polygala tenuifolia Willd, which may improve cognitive symptoms.

OBJECTIVE

This study was designed to evaluate the protective effect of TEN on inflammatory and oxidative stress induced by amyloid-β (Aβ)42 oligomers in BV2 cells, and to explore the underlying mechanisms.

METHODS

We conducted cell viability assays to estimate drug toxicity and drug effects on cells. Quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assays were performed to detect the release of inflammatory factors. Nitric oxide (NO) assays were used to measure the degree of oxidative stress. Western blot and immunofluorescence analysis were used to explore the influence of TEN on the nuclear factor-κB (NF-κB) pathway.

RESULTS

Pretreatment of BV2 microglial cells with TEN inhibited the release of tumor necrosis factor-α, interleukin-6, and interleukin-1β, alleviated NO-induced oxidative stress by inhibiting the expression of inducible nitric oxide synthase and cyclo-oxygenase-2, and protected SH-SY5Y cells from the toxicity induced by the medium conditioned by BV2 cells previously exposed to Aβ42 oligomers. Moreover, TEN suppressed upstream activators of NF-κB, as well as NF-κB translocation to the nucleus in BV2 microglial cells.

CONCLUSION

This study demonstrates that TEN can protect SH-SY5Y cells from Aβ42 oligomer-induced microglia-mediated inflammation, and oxidative stress by downregulating the NF-κB signaling pathway.

Suppression of Alzheimer's Disease-Like Pathology Progression by Mitochondria-Targeted Antioxidant SkQ1: A Transcriptome Profiling Study

Alzheimer's disease (AD) is the most common type of dementia, with increasing prevalence and no disease-modifying treatment available yet. There is increasing evidence—from interventions targeting mitochondria—that may shed some light on new strategies for the treatment of AD. Previously, using senescence-accelerated OXYS rats that simulate key characteristics of sporadic AD, we have shown that treatment with mitochondria-targeted antioxidant SkQ1 (plastoquinonyl-decyltriphenylphosphonium) from age 12 to 18 months (that is, during active progression of AD-like pathology)—via improvement of mitochondrial function—prevented the neuronal loss and synaptic damage, enhanced neurotrophic supply, and decreased amyloid-β_1–42 protein levels and tau hyperphosphorylation in the hippocampus. In the present study, we continued to explore the mechanisms of the anti-AD effects of SkQ1 in an OXYS rat model through deep RNA sequencing (RNA-seq) and focused upon the cell-specific gene expression alterations in the hippocampus. According to RNA-seq results, OXYS rats had 1,159 differentially expressed genes (DEGs) relative to Wistar rats (control), and 6-month treatment with SkQ1 decreased their number twofold. We found that 10.5% of all DEGs in untreated (control) OXYS rats were associated with mitochondrial function, whereas SkQ1 eliminated differences in the expression of 76% of DEGs (93 from 122 genes). Using transcriptome approaches, we found that the anti-AD effects of SkQ1 are associated with an improvement of the activity of many signaling pathways and intracellular processes. SkQ1 changed the expression of genes in neuronal, glial, and endothelial cells, and these genes are related to mitochondrial function, neurotrophic and synaptic activity, calcium processes, immune and cerebrovascular systems, catabolism, degradation, and apoptosis. Thus, RNA-seq analysis yields a detailed picture of transcriptional changes during the development of AD-like pathology and can point to the molecular and genetic mechanisms of action of the agents (including SkQ1) holding promise for the prevention and treatment of AD.

Calcium Ions Stimulate the Hyperphosphorylation of Tau by Activating Microsomal Prostaglandin E Synthase 1

Alzheimer’s disease (AD) is reportedly associated with the accumulation of calcium ions (Ca²⁺), and this accumulation is responsible for the phosphorylation of tau. Although several lines of evidence demonstrate the above phenomenon, the inherent mechanisms remain unknown. Using APP/PS1 Tg mice and neuroblastoma (N)2a cells as in vivo and in vitro experimental models, we observed that Ca²⁺ stimulated the phosphorylation of tau by activating microsomal PGE synthase 1 (mPGES1) in a prostaglandin (PG) E₂-dependent EP receptor-activating manner. Specifically, the highly accumulated Ca²⁺ stimulated the expression of mPGES1 and the synthesis of PGE₂. Treatment with the inhibitor of Ca²⁺ transporter, NMDAR, attenuated the expression of mPGES1 and the production of PGE₂ were attenuated in S(+)-ketamine-treated APP/PS1 Tg mice. Elevated levels of PGE₂ were responsible for the hyperphosphorylation of tau in an EP-1-, EP-2-, and EP-3-dependent but not EP4-dependent cyclin-dependent kinase (Cdk) 5-activating manner. Reciprocally, the knockdown of the expression of mPGES1 ameliorated the expected cognitive decline by inhibiting the phosphorylation of tau in APP/PS1 Tg mice. Moreover, CDK5 was found to be located downstream of EP1-3 to regulate the phosphorylation of tau though the cleavage of p35 to p25. Finally, the phosphorylation of tau by Ca²⁺ contributed to the cognitive decline of APP/PS1 Tg mice.