Role In Alzheimer's Disease Research Articles

Netrin-1's Protective Effect on A-Burdened BV2 Microglial Cells Enhanced Its Viability of Peptide Drugs for Alzheimers Disease Treatment

The rising prevalence of Alzheimers Disease (AD) has stimulated extensive research into novel therapeutic strategies. Current studies suggest peptide-based drugs are emerging as promising candidates targeting various aspects of AD pathophysiology. Microglia play a crucial role in AD due to their functions as the resident immune cells in the central nervous system, and are a prominent target for the development of peptide drugs. Netrin-1, a brain-derived extracellular factor, demonstrated therapeutic potential in AD by modulating microglial function. Here, we investigated the effects of netrin-1 on amyloid-beta (A)-burden microglia using BV2 microglial cells as a model. Cell counting was performed to assess the cell viability under different concentrations of netrin-1. Immunofluorescence was employed to examine morphological changes associated with microglial activation. To examine the polarization towards M1 or M2 phenotypes, fluorescence detection was performed after amplification. ELISA quantified A concentration to assess the protective effect of netrin-1. Microglial gene expression influenced by A was identified in the Gene Expression Omnibus (GEO) database (GSE227221). Expression levels of netrin-1 receptors were analyzed to identify potential targets. Protein structures from the RCSB database were docked with netrin-1 using PyMOL to identify the amino acids on the binding interface that may stimulate the receptors and mitigate A-induced damage. Specifically, a concentration of 100 ng/mL of netrin-1 optimally maintained cell viability in the presence of A. Netrin-1 could lessen A-induced microglial activation, especially M2 activation phenotype. ELISA data showed that netrin-1 treatment significantly improved the phagocytic abilities of A-burden BV2 cells. Analysis of the GEO database revealed that the expressions of DCC, DSCAM, and UNC5a were significantly elevated following A treatment in microglia. Eight potential polypeptides were identified as the potential targets for netrin-1 binding. In conclusion, netrin-1 mitigated the A-induced damage in microglia through its protective effects. The eight identified peptides of netrin-1 may represent a significant advancement toward developing drugs targeting A-related AD pathology. Netrin-1 based peptide drugs hold novel therapeutic promise for AD

Roles of the Receptor for Advanced Glycation End Products and Its Ligands in the Pathogenesis of Alzheimer's Disease.

The Receptor for Advanced Glycation End Products (RAGE), part of the immunoglobulin superfamily, plays a significant role in various essential functions under both normal and pathological conditions, especially in the progression of Alzheimer's disease (AD). RAGE engages with several damage-associated molecular patterns (DAMPs), including advanced glycation end products (AGEs), beta-amyloid peptide (Aβ), high mobility group box 1 (HMGB1), and S100 calcium-binding proteins. This interaction impairs the brain's ability to clear Aβ, resulting in increased Aβ accumulation, neuronal injury, and mitochondrial dysfunction. This further promotes inflammatory responses and oxidative stress, ultimately leading to a range of age-related diseases. Given RAGE's significant role in AD, inhibitors that target RAGE and its ligands hold promise as new strategies for treating AD, offering new possibilities for alleviating and treating this serious neurodegenerative disease. This article reviews the various pathogenic mechanisms of AD and summarizes the literature on the interaction between RAGE and its ligands in various AD-related pathological processes, with a particular focus on the evidence and mechanisms by which RAGE interactions with AGEs, HMGB1, Aβ, and S100 proteins induce cognitive impairment in AD. Furthermore, the article discusses the principles of action of RAGE inhibitors and inhibitors targeting RAGE-ligand interactions, along with relevant clinical trials.

The causal role of lipids in dementia: A Mendelian randomization study

Background Increasing evidence suggests that abnormal lipid metabolism is one of the pathogeneses of dementia. It is necessary to reveal the relationship between lipids and dementia. Objective This study used bidirectional two-sample Mendelian randomization to explore the causal relationship between 179 lipid species and the risk of dementia. Methods We assessed the causal effects of 179 lipid species and four subtypes of dementia including Alzheimer's disease (AD), vascular dementia (VaD), frontotemporal dementia (FTD), and dementia with Lewy bodies (DLB). Inverse variance weighting, MR-Egger method, weighted median, simple mode, and weighted mode were used to analyze the relationship between lipids and dementia. Cochran's Q, MR-Egger intercept test, and MR-PRESSO test were used to test the heterogeneity and pleiotropy of the results. In addition, we performed an inverse MR analysis testing the causal effects of dementia on lipids. Results Our study revealed causal effects of glycerophospholipid, glycerolipid, and sterol on the risk of dementia. Phosphatidylcholine, phosphatidylinositol, and triglycerides play significant roles in AD. Notably, phosphatidylcholine played a protective role in both FTD and DLB. However, this study did not observe a significant effect of phosphatidylinositol on FTD. In the case of VaD, not only glycerophospholipid, but also glycerolipid, exerted an influence, but sterol was also a risk factor. Conclusions Our study provided new evidence supporting the causal role of genetically predicted lipid species in dementia. Future clinical trials are necessary to evaluate the potential role of lipid levels in dementia prevention.

Ginkgo biloba extract EGb 761® ameliorates cognitive impairment and alleviates TNFα response in 5xFAD Alzheimer's disease model mice.

Ginkgo biloba leaf extract EGb 761® has shown clinical efficacy in patients with mild cognitive impairment and dementia. However, the pharmacological action of EGb 761® in Alzheimer's disease (AD) remains unclear and molecular mechanisms targeted in the brain are not completely understood. We aimed to investigate 1) the potential sex-dependent effects of oral administration of EGb 761® in 5xFAD mice, an AD mouse model, and 2) the underlying microglial subtype responsible for the observed anti-inflammatory effects in the brain. Eight-week old 5xFAD and wild type mice received EGb 761®-supplemented diet or control diet for eight weeks. The study investigated changes in cognitive function as well as amyloid plaque load, expression of AD-related genes, and anti-inflammatory effects. Moreover, we used organotypic brain slices for confirmation and assessment of concentration-dependency of the observed EGb 761® effects and performed single cell RNA sequencing on the prefrontal cortex of male mice with focus on microglia. We demonstrate that EGb 761® treatment improves cognitive function in 5xFAD mice in several behavioral tests. Analysis of the brain tissue from these animals indicated a reduction in amyloid plaque load in the prefrontal cortex (PFC). This brain area was further investigated to assess the molecular changes that occurred following EGb 761® intake. Alterations in the expression of genes related to AD were highly sex-specific with effects on the cholinergic system, the γ-secretase complex, and neuroinflammation. Anti-inflammatory effects of EGb 761® with a particularly pronounced reduction of the TNFα-response could be shown for the PFC but also peripherally in the serum of 5xFAD mice of both sexes. Single-cell RNA sequencing revealed that EGb761® mainly affected disease-associated microglia stage 2 (DAM2), which are thought to have a detrimental role in AD. EGb 761® shows efficacy in the treatment of cognitive deficits in the 5xFAD mouse model via multimodal activity, including sex-specific and sex-unrelated mechanisms including the normalization of neuroinflammatory parameters.

Identifying Hub Genes and miRNAs Associated with Alzheimer's Disease: A Bioinformatics Pathway to Novel Therapeutic Strategies.

Alzheimer's disease (AD) is a neurodegenerative disorder that mainly affects the elderly population. It is characterized by cognitive impairment and dementia due to abnormal levels of amyloid beta peptide (Aβ) and axonal Tau protein in the brain. However, the complex underlying mechanisms affecting this disease are not yet known, and there is a lack of standardized biomarkers and therapeutic targets. Therefore, in this study, by means of bioinformatics analysis, AD-affected brain tissue was analyzed using the GSE138260 dataset, identifying 612 differentially expressed genes (DEGs). Functional analysis revealed 388 upregulated DEGs associated with sensory perception and 224 downregulated DEGs linked to the regulation and modulation of synaptic processes. Protein-protein interaction network analysis identified 20 hub genes. Furthermore, miRNA target gene networks revealed 1767 miRNAs linked to hub genes, among which hsa-mir-106a-5p, hsa-mir-17-5p, hsa-mir-26a-5p, hsa-mir-27a-3p and hsa-mir-34a-5p were the most relevant. This study presents novel biomarkers and therapeutic targets for AD by analyzing the information obtained with a comprehensive literature review, providing new potential targets to study their role in AD.

Serotonin enhances neurogenesis biomarkers, hippocampal volumes, and cognitive functions in Alzheimer’s disease

Research on serotonin reveals a lack of consensus regarding its role in brain volume, especially concerning biomarkers linked to neurogenesis and neuroplasticity, such as ciliary neurotrophic factor (CNTF), fibroblast growth factor 4 (FGF-4), bone morphogenetic protein 6 (BMP-6), and matrix metalloproteinase-1 (MMP-1) in Alzheimer’s disease (AD). This study aimed to investigate the influence of serotonin on brain structure and hippocampal volumes in relation to cognitive functions in AD, as well as its link with biomarkers like CNTF, FGF-4, BMP-6, and MMP-1. Data from 133 ADNI participants with AD included cognitive assessments (CDR-SB), serotonin measurements (Biocrates AbsoluteIDQ p180 kit, UPLC-MS/MS), and neurotrophic factors quantified via multiplex proteomics. Gray matter volume changes were analyzed using Voxel-Based Morphometry (VBM) with MRI. Statistical analyses employed Pearson correlation, bootstrap methods, and FDR-adjusted p-values (< 0.05 or < 0.01) via the Benjamini–Hochberg procedure, alongside nonparametric methods. The analysis found a positive correlation between serotonin levels and total brain (r = 0.229, p = 0.023) and hippocampal volumes (right: r = 0.186, p = 0.032; left: r = 0.210, p = 0.023), even after FDR adjustment. Higher serotonin levels were linked to better cognitive function (negative correlation with CDR-SB, r = −0.230, p = 0.024). Notably, serotonin levels were positively correlated with BMP-6 (r = 0.173, p = 0.047), CNTF (r = 0.216, p = 0.013), FGF-4 (r = 0.176, p = 0.043), and MMP-1 (r = 0.202, p = 0.019), suggesting a link between serotonin and neurogenesis and neuroplasticity. However, after adjusting for multiple comparisons and controlling for confounding factors such as age, gender, education, and APOE genotypes (APOE3 and APOE4), none of the correlations of biomarkers remained statistically significant. In conclusion, increased serotonin levels are associated with improved cognitive function and increased brain volume. However, associations with CNTF, FGF-4, BMP-6, and MMP-1 were not statistically significant after adjustments, highlighting the complexity of serotonin’s role in AD and the need for further research.Graphical

Plasticity of Human Microglia and Brain Perivascular Macrophages in Aging and Alzheimer's Disease.

The complex roles of myeloid cells, including microglia and perivascular macrophages, are central to the neurobiology of Alzheimer's disease (AD), yet they remain incompletely understood. Here, we profiled 832,505 human myeloid cells from the prefrontal cortex of 1,607 unique donors covering the human lifespan and varying degrees of AD neuropathology. We delineated 13 transcriptionally distinct myeloid subtypes organized into 6 subclasses and identified AD-associated adaptive changes in myeloid cells over aging and disease progression. The GPNMB subtype, linked to phagocytosis, increased significantly with AD burden and correlated with polygenic AD risk scores. By organizing AD-risk genes into a regulatory hierarchy, we identified and validated MITF as an upstream transcriptional activator of GPNMB, critical for maintaining phagocytosis. Through cell-to-cell interaction networks, we prioritized APOE-SORL1 and APOE-TREM2 ligand-receptor pairs, associated with AD progression. In both human and mouse models, TREM2 deficiency disrupted GPNMB expansion and reduced phagocytic function, suggesting that GPNMB's role in neuroprotection was TREM2-dependent. Our findings clarify myeloid subtypes implicated in aging and AD, advancing the mechanistic understanding of their role in AD and aiding therapeutic discovery.

Novel insights into Cntnap4 in Alzheimer's disease: Intestinal flora interaction.

Alzheimer's disease (AD) is a neurodegenerative disorder with unclear etiology. This study employs single-cell RNA sequencing (scRNA-seq), high-throughput transcriptome sequencing, 16s rRNA sequencing, and animal experiments to investigate the role of the contactin-associated protein like-4 (Cntnap4) gene in AD and its interaction with intestinal flora. We found that Cntnap4 deficiency in AD mice led to increased Tau protein phosphorylation, amyloid-beta plaque accumulation, and neuronal loss. Astrocytes in Cntnap4-/- mice showed impaired amyloid-beta processing. 16s rRNA sequencing revealed distinct intestinal flora compositions between Cntnap4-/- and control mice, indicating a potential link between gut microbiota and AD progression. Notably, GABA supplementation improved cognitive impairment, restored synaptic currents, reduced amyloid-beta plaques, and increased neuronal counts. This study highlights Cntnap4's critical role in AD and suggests gut-brain axis involvement, offering novel insights for potential therapeutic strategies.

Upregulation of ISG15 induced by MAPT/tau accumulation represses autophagic flux by inhibiting HDAC6 activity: a vicious cycle in alzheimer disease

ABSTRACT Alzheimer disease (AD), a prevalent neurodegenerative condition in the elderly, is marked by a deficit in macroautophagy/autophagy, leading to intracellular MAPT/tau accumulation. While ISG15 (ISG15 ubiquitin like modifier) has been identified as a regulator of selective autophagy in ataxia telangiectasia (A-T), its role in AD remains unexplored. Our study reveals elevated ISG15 levels in the brains of patients with sporadic AD and AD models in vivo and in vitro. ISG15 overexpression in cells and the hippocampus inhibited HDAC6 (histone deacetylase 6) activity through C-terminal LRLRGG binding to HDAC6. Consequently, this increased CTTN (cortactin) acetylation, disrupted CTTN and F-actin recruitment to lysosomes, and impaired autophagosome (AP)-lysosome (LY) fusion. These disruptions led to MAPT/tau accumulation, synaptic damage, neuronal loss, and cognitive deficits. Conversely, ISG15 knockdown in our HsMAPT (human MAPT) pathology model restored HDAC6 activity, promoted AP-LY fusion, and improved cognitive function. This study identifies ISG15 as a key regulator of autophagic flux in AD, suggesting that targeting ISG15-mediated autophagy could offer therapeutic potential for AD.

Construction of a Dataset for All Expressed Transcripts for Alzheimer's Disease Research.

Accurate identification and functional annotation of splicing isoforms and non-coding RNAs (lncRNAs), alongside full-length protein-encoding transcripts, are critical for understanding gene (mis)regulation and metabolic reprogramming in Alzheimer's disease (AD). This study aims to provide a comprehensive and accurate transcriptome resource to improve existing AD transcript databases. Background/Objectives: Gene mis-regulation and metabolic reprogramming play a key role in AD, yet existing transcript databases lack accurate and comprehensive identification of splicing isoforms and lncRNAs. This study aims to generate a refined transcriptome dataset, expanding the understanding of AD onset and progression. Methods: Publicly available RNA-seq data from pre-AD and AD tissues were utilized. Advanced bioinformatics tools were applied to assemble and annotate full-length transcripts, including splicing isoforms and lncRNAs, with an emphasis on correcting errors and enhancing annotation accuracy. Results: A significantly improved transcriptome dataset was generated, which includes detailed annotations of splicing isoforms and lncRNAs. This dataset expands the scope of existing AD transcript databases and provides new insights into the molecular mechanisms underlying AD. The findings demonstrate that the refined dataset captures more relevant details about AD progression compared to publicly available data. Conclusions: The newly developed transcriptome resource and the associated analysis tools offer a valuable contribution to AD research, providing deeper insights into the disease's molecular mechanisms. This work supports future research into gene regulation and metabolic reprogramming in AD and serves as a foundation for exploring novel therapeutic targets.

Therapeutic efficacy of amygdaline and amygdaline-loaded niosomes in a rat model of Alzheimer’s disease via oxidative stress, brain neurotransmitters, and apoptotic pathway

Abstract Background Alzheimer’s disease (AD) is a specific form of neurodegeneration that is marked by impairments in memory and cognition. Exposure to some metal toxins, such as aluminum (AL), was directly linked to the onset of AD as it was hosted in the body via several exposure routes and can change the permeability and cross the blood–brain barrier. Due to amygdaline’s existence, apricot kernel therapy for AD is believed to have been established to be successful in numerous investigations. Amygdaline has been shown to have antioxidant effects that mitigate oxidative damage, and free radicals scavenger activity, as well as amygdaline niosomes as a nanoparticle has been found to improve the drug’s efficiency and selectivity. The objectives of this investigation are to study the neuroprotective role of amygdaline, and amygdaline-loaded niosomes formulation in the diminishment of the incidence of AD in neurotoxin (aluminum chloride; AlCl3) AD animal model. Results Data revealed that AlCl3 caused cognitive decline that was confirmed by cognitive behavioral tests (novel object and Y-maze); biochemical disturbances that include marked oxidative stress (elevated malondialdehyde and reduced total antioxidant capacity), reduced acetylcholinesterase, and brain monoamines levels (nor adrenalin; 4-dihydroxyphenylacetic acid; 5-hydroxytryptamine /serotonin; dopamine), and gene regulation upset (down-regulated transcript levels of acetylcholinesterase; monoamine oxidase; BCL-2 and up-regulated transcript levels of BAX), as well as neurodegenerative changes were observed in the hippocampus of AlCl3-treated rats. Treatment with amygdaline and amygdaline-loaded niosomes formulation improved working memory and recognition, alleviated oxidative stress, and restored the levels of brain monoamines and neurotransmitters. Moreover, gene expression data showed a significant down-regulation of BAX, while BCL-2, acetylcholinesterase, and monoamine oxidase were significantly up-regulated. Additionally, the histopathological examination showed reduced neurodegeneration. Conclusion Conclusively, it was evident that amygdaline and amygdaline-loaded niosomes formulation possess a neuroprotective and cognitive enhancement role in AD via their potent antioxidant potential, neurotransmitters, and gene expression regulations, as well as neural damage reduction capability. Graphical abstract

Causal Effects of Kidney Function and Chronic Kidney Disease on Alzheimer's Disease by Analyzing Large-Scale Genome-Wide Association Study Datasets.

Alzheimer's disease (AD) is the leading cause of dementia. Genetic components play an important role in AD and have been widely evaluated by genome-wide association studies (GWAS) and exome sequencing, and some common and rare genetic variants have been identified. In addition to genetic factors, environment factors have a role in AD. Growing evidence from observational studies linked impaired kidney function to cognitive impairment and AD; however, there are inconsistences in these findings. To determine the causal effects of impaired kidney function and chronic kidney disease (CKD) on AD. Mendelian randomization (MR) methods have been widely used to infer causal associations between exposure and outcome. Here, we conducted an MR study to investigate the causal effects of impaired kidney function and CKD on the risk of AD by analyzing large-scale GWAS datasets from FinnGen and CKD Genetics (CKDGen) Consortium. We found no significant but a suggestive effect of CKD on decreased risk of AD using inverse-variance weighted (IVW) (p = 8.46E-02) and simple mode (p = 7.60E-02) methods. We identified a statistically significant effect of the estimated glomerular filtration rate (eGFR) on increased risk of AD using IVW (p = 1.11E-02), weighted median regression (p = 5.60E-03), and weighted mode (p = 2.45E-02) methods. Together, our findings indicate that high eGFR levels may increase the risk of AD. These findings need to be verified in future studies.

A microglia-containing 3D human brain organoid for studying HSV-1-induced Alzheimer’s disease

As a progressive neurodegenerative disorder, Alzheimer’s disease (AD) can result in significant memory loss and cognitive deterioration. Several recent studies show that herpes simplex virus type I (HSV-1) is closely related to AD pathology. Microglia, the primary immune cells in the central nervous system, are also shown to play an important role in AD. In this study, we developed a microglia-containing 3-dimensional (3D) human brain organoid from human-induced pluripotent stem cells (hiPSCs) to study the relationship between microglia and HSV-1-induced AD phenotypes. We found that microglia increased the generation of amyloid-β protein (Aβ) and neurofibrillary tangles (NFTs), contributed to neural loss, and enhanced gliosis and neuroinflammation. We also employed shRNA vectors to inhibit certain cytokines related to neuroinflammation and examined the impact on Aβ aggregation. This model can facilitate future research on the treatment of AD regarding microglia and HSV-1.

Identification of Phytoconstituents from Natural Product Database as SIRT2 Inhibitors for Potential Role in Alzheimer's Disease: An In-Silico Screening.

We aimed to conduct in silico screening of the potential phytoconstituent from a natural product database to find SIRT2 inhibitors. Alzheimer's disease (AD) is the most prevalent type of dementia, characterized by behavioral and mental symptoms as well as a progressive loss of cognitive ability. Since SIRT2 may be detrimental to neurological illnesses, it is a prime target for research into SIRT2 inhibitors. To identify the SIRT2 inhibitors and their role in AD. We have utilized NPAtlas database and screened using pharmacophore-based virtual screening, molecular docking, and simulation. The Natural Products Atlas provides unrestricted access to various natural products derived from bacteria and fungi, allowing researchers to investigate and visualize the extensive chemical diversity in the natural world. From in silico screening data, we have found phytoconstituents that could function as SIRT2 inhibitors. Six phytoconstituents were identified using pharmacophore-based virtual screening. According to molecular docking, Kurasoin B outperformed the reference molecule regarding binding energy. Kurasoin B exhibited a binding affinity of -12.543 kcal/mol, whereas the binding affinity of the reference molecule was -12.089 kcal/mol. The Kurasoin B complex with SIRT2 was determined to be stable throughout the simulation by performing MD simulation, with an RMSD of 2.88 (Å), whereas the reference and free protein displayed RMSDs of 3.74 and 4.70 (Å), respectively. In silico studies and data analysis, suggest that Kurasoin B may be able to suppress the SIRT2 protein for managing AD.

Gut microbiome-derived metabolites in Alzheimer's disease: Regulation of immunity and potential for therapeutics.

Alzheimer's disease (AD) is the most common neurodegenerative disorder and cause of dementia. Despite the prevalence of AD, there is a lack of effective disease modifying therapies. Recent evidence indicates that the gut microbiome (GMB) may play a role in AD through its regulation of innate and adaptive immunity. Gut microbes regulate physiology through their production of metabolites and byproducts. Microbial metabolites may be beneficial or detrimental to the pathogenesis and progression of inflammatory diseases. A better understanding of the role GMB-derived metabolites play in AD may lead to the development of therapeutic strategies for AD. In this review, we summarize the function of bioactive GMB-derived metabolites and byproducts and their roles in AD models. We also call for more focus on this area in the gut-brain axis field in order to create effective therapies for AD.

Early wave reflection of carotid artery is associated with 18F-FDG PET hypometabolism in Alzheimer's brain areas of cognitively normal adults.

Arterial stiffening likely plays a role in Alzheimer disease (AD) pathogenesis. The current study investigated whether inter-individual variations in arterial stiffness and pressure wave parameters were associated with 18F-FDG positron emission tomography (PET) metabolism in AD-associated brain areas throughout adulthood, independently of age and before the onset of any neuropsychological disorders. A prospective, large age-range population of 67 patients (17 young, 16 middle-aged, and 34 older adults; 37 women) underwent a: brain 18F-FDG PET, blood pressure recording, and carotid/femoral pulse wave-based measurements, including the time-to-peak of the reflected backward carotid pulse wave (bT), on the same day. Multivariable and quantitative voxel-to-voxel analyses (P-voxel < 0.005, corrected for cluster volumes) were conducted to assess associations between vascular parameters and 18F-FDG PET metabolism in AD-associated brain areas. In the multivariable analysis, only increased age and decreased bT were independently associated with the decline of metabolic activity in AD-associated brain areas (P < 0.001). In the voxel-to-voxel analysis with age as a covariate, bT was strongly associated with the metabolic activity of 40 clusters in AD-associated brain areas (clusters cumulative volume: 63 cm3; T score max: 5.7). In a large age-range population of adult patients, who are still unaffected by neuropsychological disorders, an early reflected arterial pressure wave, as evidenced by a decreased bT value, is strongly associated with hypometabolic activity of AD-associated brain areas, independently of age.

Neobavaisoflavone Ameliorates Memory Deficits and Brain Damage in Aβ25-35-Induced Mice by Regulating SIRT1.

Alzheimer's disease (AD) is a common chronic neurodegenerative disease in older people, and there is no specific treatment that can stop or reverse its progression. Neobavaisoflavone (NBIF) is a flavonoid that has been shown to have neuroprotective effects, but its role in AD has not been revealed. The present study investigated the role and mechanism of NBIF on Aβ25-35-induced brain injury. In this experiment, the AD mouse model was established by injection of Aβ25-35 peptides (200 μM, icv), and Donepezil (Don, 10 mg/kg/days), NBIF-L (15 mg/kg/days), and NBIF-H (30 mg/kg/days) were administered orally for 4 weeks. Learning memory, hippocampal pathological changes, pathological markers, apoptosis, oxidative stress, inflammation, immune cells were measured in mice. Network pharmacology combined with the GEO database led to the identification of SIRT1, a key target for NBIF intervention in AD, and levels of SIRT1, p-STAT3 and FOXO1 were measured. In addition, the antagonistic activity of SIRT1 transfection silencing against NBIF in Aβ25-35-induced in N9 cells and N2a-APP69 cells was investigated to assess whether the effects caused by NBIF were mediated by SIRT1. The results showed that NBIF ameliorated learning memory and hippocampal neuronal damage, reduced pathological markers, apoptosis, oxidative stress and neuroinflammation, and modulated immune cells. SIRT1 is a key target for NBIF intervention in AD, and NBIF upregulates SIRT1 and reduces the expression levels of p-STAT3 and FOXO1. Furthermore, silencing SIRT1 effectively reduced the protective effect of NBIF on Aβ25-35-induced N9 cells and N2a-APP69 cells, which indicated that the protective effect of NBIF on AD is related to SIRT1. NBIF ameliorated Aβ25-35-induced brain injury by inhibiting apoptosis, oxidative stress, and neuroinflammation, which may be mediated through SIRT1 signaling. These findings provide a rationale for NBIF in the treatment of AD and help facilitate the development of clinical therapeutic agents for AD.

Altered copper transport in oxidative stress-dependent brain endothelial barrier dysfunction associated with Alzheimer's disease

Oxidative stress and blood-brain barrier (BBB) disruption due to brain endothelial barrier dysfunction contribute to Alzheimer's Disease (AD), which is characterized by beta-amyloid (Aβ) accumulation in senile plaques. Copper (Cu) is implicated in AD pathology and its levels are tightly controlled by several Cu transport proteins. However, their expression and role in AD, particularly in relation to brain endothelial barrier function remains unclear. In this study, we examined the expression of Cu transport proteins in the brains of AD mouse models as well as their involvement in Aβ42-induced brain endothelial barrier dysfunction. We found that the Cu uptake transporter CTR1 was upregulated, while the Cu exporter ATP7A was downregulated in the hippocampus of AD mouse models and in Aβ42-treated human brain microvascular endothelial cells (hBMECs). In the 5xFAD AD mouse model, Cu levels (assessed by ICP-MS) were elevated in the hippocampus. Moreover, in cultured hBMECs, Aβ42-induced reactive oxygen species (ROS) production, ROS-dependent loss in barrier function (measured by transendothelial electrical resistance), and tyrosine phosphorylation of CDH5 were all inhibited by either a membrane permeable Cu chelator or by knocking down CTR1 expression. These findings suggest that dysregulated expression of Cu transport proteins may lead to intracellular Cu accumulation in the AD brain, and that Aβ42 promotes ROS-dependent brain endothelial barrier dysfunction and CDH5 phosphorylation in a CTR1-Cu-dependent manner. Our study uncovers the critical role of Cu transport proteins in oxidative stress-related loss of BBB integrity in AD.

Microglial Drivers of Alzheimer's Disease Pathology: AnEvolution of Diverse Participating States.

Microglia, the resident immune-competent cells of the brain, become dysfunctional in Alzheimer's disease (AD), and their aberrant immune responses contribute to the accumulation of pathological proteins and neuronal injury. Genetic studies implicate microglia in the development of AD, prompting interest in developing immunomodulatory therapies to prevent or ameliorate disease. However, microglia take on diverse functional states in disease, playing both protective and detrimental roles in AD, which largely overlap and may shift over the disease course, complicating the identification of effective therapeutic targets. Extensive evidence gathered using transgenic mouse models supports an active role of microglia in pathology progression, though results vary and can be contradictory between different types of models and the degree of pathology at the time of study. Here, we review microglial immune signaling and responses that contribute to the accumulation and spread of pathological proteins or directly affect neuronal health. We additionally explore the use of induced pluripotent stem cell (iPSC)-derived models to study living human microglia and how they have contributed to our knowledge of AD and may begin to fill in the gaps left by mouse models. Ultimately, mouse and iPSC-derived models have their own limitations, and a comprehensive understanding of microglial dysfunction in AD will only be established by an integrated view across models and an appreciation for their complementary viewpoints and limitations.

ABCA7-dependent induction of neuropeptide Y is required for synaptic resilience in Alzheimer’s disease through BDNF/NGFR signaling

Genetic variants in ABCA7, an Alzheimer's disease (AD)-associated gene, elevate AD risk, yet its functional relevance to the etiology is unclear. We generated a CRISPR-Cas9-mediated abca7 knockout zebrafish to explore ABCA7's role in AD. Single-cell transcriptomics in heterozygous abca7+/- knockout combined with Aβ42 toxicity revealed that ABCA7 is crucial for neuropeptide Y (NPY), brain-derived neurotrophic factor (BDNF), and nerve growth factor receptor (NGFR) expressions, which are crucial for synaptic integrity, astroglial proliferation, and microglial prevalence. Impaired NPY induction decreased BDNF and synaptic density, which are rescuable with ectopic NPY. In induced pluripotent stem cell-derived human neurons exposed to Aβ42, ABCA7-/- suppresses NPY. Clinical data showed reduced NPY in AD correlated with elevated Braak stages, genetic variants in NPY associated with AD, and epigenetic changes in NPY, NGFR, and BDNF promoters linked to ABCA7 variants. Therefore, ABCA7-dependent NPY signaling via BDNF-NGFR maintains synaptic integrity, implicating its impairment in increased AD risk through reduced brain resilience.