📋 Browse Articles

The protease β-secretase (BACE1) plays a crucial role in the formation of amyloid-beta peptides. Here, we present a protocol for real-time quantification of BACE1 activity in brain tissue and cell lysates using a fluorogenic peptide substrate in a 96-well format. We describe steps for reagent and sample preparation, preparing the plate for BACE1 activity, and incubating and reading the plate, followed by quantification and analysis. This protocol is broadly accessible for laboratories studying enzymatic activity under physiological or pathological conditions. For complete details on the use and execution of this protocol, please refer to Baranowski et al. Show less

Ferroptosis is an iron-dependent and membrane lipid peroxidation-mediated form of programmed or regulated cell death. A number of recent studies have demonstrated that ferroptosis contributes to Alzheimer's disease (AD)-mediated nerve cell death. Melatonin demonstrates strong antioxidant properties and offers protective benefits for the brain in the context of AD. However, it is not fully known whether melatonin protects against ferroptosis and whether ferroptosis affects amyloid precursor protein (APP) processing. In this study, we studied the effects of melatonin on SH-SY5Y cells-induced ferroptosis using erastin, and ferrostatin-1 was used as a ferroptosis inhibitor. To confirm the occurrence of ferroptosis, we conducted measurements of cell cytotoxicity, intracellular iron, reactive oxygen species (ROS), and 4-hydroxynonenal (4-HNE). The protein expressions that were regulated by either ferroptosis or APP processing were measured. Our results revealed that erastin increased intracellular iron levels, ROS, and 4-HNE lipid peroxidation in SH-SY5Y cells, resulting in an increased percentage of cell death. Erastin disrupted the regulation of proteins involved in ferroptosis and increased the production of amyloid beta (Aβ) through APP proteolysis. Following melatonin treatment, intracellular iron, ROS, and 4-HNE levels were significantly reduced. Additionally, the cystine/glutamate antiporter (system xc Show less

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by amyloid-beta (Aβ) plaque deposition and neurofibrillary tangles, which collectively drive neuroinflammation, synaptic dysfunction, and cognitive decline. Here, we investigated whether a peptide epitope vaccine targeting the Aβ1-10 sequence could mitigate Aβ-induced pathology in AD mouse model. Three Aβ1-10 peptides, i.e. Aβ1-10-N, Aβ1-10-D1H, and Aβ1-10-S8R were synthesized, and Aβ1-10-S8R was further conjugated to ovalbumin (OVA) or keyhole limpet hemocyanin (KLH) to enhance immunogenicity. Among seven treatment groups, Aβ1-10-D1H and Aβ1-10-S8R, particularly when conjugated to OVA or KLH, effectively suppressed Aβ, amyloid-beta precursor protein (APP), and beta-secretase 1 (BACE-1) expression, decreased inflammatory cytokine production by astrocytes and microglia, and increased the levels of key synaptic markers (synaptophysin, synaptosomal-associated protein 23 [SNAP-23], postsynaptic density protein 95 [PSD-95]). Carrier protein conjugation also elevated immunoglobulin G (IgG) levels in the spleen, indicative of a robust humoral response. Taken together, these findings demonstrate that Aβ1-10-based immunization, especially with OVA or KLH conjugation, reduces Aβ-driven neuroinflammation, synaptic dysfunction, and memory deficits, suggesting a promising immunotherapeutic strategy for AD. Show less

Alzheimer's disease (AD) is a multifactorial neuropathology characterized by the accumulation of amyloid-beta (Aβ) plaques, neurofibrillary tangles (NFTs) and cholinergic system dysfunction. At present, there is no effective treatment strategy for AD. Our previous research showed that ZJQ-3F acts as an inhibitor of AChE/BACE1/GSK3β, and showed good blood-brain barrier permeability, appropriate bioavailability and oral safety. In order to further study, the protective effect of ZJQ-3F on APP/PS1/Tau transgenic mice was determined. APP/PS1/Tau transgenic mice model of AD was treated with ZJQ-3F from the age of 8 to 12 months, and then behavioral tests was conducted. Western blot, immunohistochemistry and immunofluorescence staining were used to evaluate the level of tau protein, Aβ plaques and synaptic function. Our results revealed that administration of ZJQ-3F could improve the cognitive function of APP/PS1/Tau transgenic mice. In addition, compared with APP/PS1/Tau mice, the protein expression levels of tau protein phosphorylation site at Ser396, Thr212 and Thr181 in the cortex and hippocampus of ZJQ-3F treated mice was significantly decreased. Moreover, the results showed that ZJQ-3F significantly reduced the deposition of Aβ in the cortex and hippocampus. Furthermore, the results indicated that the protein expression levels of PSD95, SYP and SYT in the cortex and hippocampus were increased markedly after ZJQ-3F was given. Our studies suggest that the chronic administration of ZJQ-3F can improve learning and memory ability, reduce tau protein phosphorylation, reduce Aβ deposition and improve synaptic dysfunction in APP/PS1/Tau transgenic model of AD, indicating that ZJQ-3F can be used as a multi-target inhibitor to slow down the progress of AD. Show less

Inhibition of amyloid precursor protein (APP) beta-site cleaving enzyme 1 (BACE1) has been a target for Alzheimer's disease (AD) therapeutic development. Here, we report our identification of APP-selective BACE1 (ASBI) inhibitors that are selective for APP as the substrate and BACE1 as the target enzyme. A known fluoro aminohydantoin (FAH) inhibitor compound was identified by screening a compound library for inhibition of BACE1 cleavage of a maltose binding protein (MBP)-conjugated-APPC125 substrate followed by optimization and IC50 determination using the P5-P5' activity assay. Optimization of the screening hit led to candidate FAH65, which displays selectivity for inhibition of APP cleavage with little activity against other BACE1 substrates neuregulin 1 (NRG1) or p-selectin glycoprotein ligand-1 (PSGL1). FAH65 shows little inhibitory activity against other aspartyl proteases cathepsin D (Cat D) and BACE2. FAH65 reduces BACE1 cleavage products soluble APPβ (sAPPβ) and the β C-terminal fragment (βCTF), as well as amyloid-β (Aβ) 1-40 and 1-42, both in vitro in cells and in vivo in an animal model of AD. In a murine model of AD, FAH65 improved the discrimination score in the Novel Object Recognition (NOR) memory testing paradigm. The active enantiomer of racemate FAH65, FAH65E(-), displays good brain-penetrance and target engagement, meriting further pre-clinical development as an ASBI that may reduce Aβ levels and overcome the deleterious effects of the non-selective BACE1 inhibitors that have failed in the clinic. FAH65E(-) has the potential to be a first-in-class oral therapy that could be used in conjunction with an approved anti-Aβ antibody therapy for AD. Show less

Individuals with type 2 diabetes mellitus have an increased risk of developing Alzheimer's disease (AD). GLP-1 receptor agonists (GLP-1RAs) are used for glycemic control in diabetes and show potential neuroprotective properties, but their effects on AD and the underlying mechanisms are not well understood. Here we demonstrate that GLP-1RAs can alleviate AD-related phenotypes by activating 5' AMP-activated protein kinase (AMPK) signaling. We found that plasma GLP-1 levels were decreased in AD model mice and negatively correlated with amyloid-beta (Aβ) load in patients with AD. Enhancing GLP-1 signaling through GLP-1RAs increased CaMKK2-AMPK signaling, which subsequently reduced BACE1-mediated cleavage of amyloid precursor protein (APP) and Aβ generation. GLP-1RAs also increased AMPK activity in microglia, inhibiting neuroinflammation and promoting Aβ phagocytosis. Consequently, GLP-1RAs inhibited plaque formation and improved memory deficits in AD model mice. Our findings indicate that AMPK activation mediates the effects of GLP-1RAs on AD, highlighting the therapeutic potential of GLP-1RAs for the treatment of AD. Show less

The present study aimed to assess the pharmacological mechanism of Salvia officinalis in Neurodegenerative disorders using a network pharmacology approach followed by molecular docking analysis. Phytoconstituents of S.officinalis were obtained from various databases, followed by the screening of active ingredients using the Swiss ADME web tool. Potential targets of active ingredients were identified using PubChem & SwissTargetPrediction. Genes related to Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD) were gathered using online databases. Besides, the correlation between active ingredient targets and disease-associated genes was linked. Networks were constructed, visualized, and analyzed using Cytoscape. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genome (KEGG) pathway enrichment analysis were performed using DAVID database. Decisively, Autodock was used for molecular docking. The results of network analysis identified 9 key active ingredients based on topological analysis of the active ingredient-candidate targets network. Also, the analysis revealed a shared target of 9 key active ingredients of S. officinalis that interacted with 133 AD-related targets whereas only 6 active ingredients interacted with 85 and 58 targets of PD and HD respectively. The core genes from the network were AKT1, BACE1, CASP3, MAPK1, TNF, and IL6. Furthermore, GO and KEGG enrichment analysis showed that FOXO, TNF, MAPK, PI3K-Akt, Rap 1, and neurotrophin signalling pathways as enriched, which were further evaluated by molecular docking suggesting the protective role of S. officinalis in neurodegenerative diseases. Our research reveals the therapeutic benefits of S. officinalis, which might play a crucial role in modulating neurodegenerative diseases. Show less

Alzheimer's disease (AD), the most common neurodegenerative disease in humans, has been a major medical challenge. Lactoferrin (Ltf) in salivary glands might be identified as a potential detectable biomarker in AD and a therapeutic target for AD. Pharmaceutical studies directly addressing this biomarker, though, are scarce. Using a computational strategy for drug repurposing, we explored the proximal neighborhood of Ltf by exploring its interactome and regulatory constellations. We aimed to focus on the discovery of potential therapeutic agents for AD. Based on extensive analytical evaluation comprising structural congruence scales, profiling disease clusters, pathway enrichment analyses as well as molecular docking, SPR, in vivo studies, and immunofluorescence assays, our research identified three candidate repurposed drugs: Lovastatin, SU-11652, and SB-239063. Taken together, these results highlight strong binding affinities of the drug candidates to Ltf. In vitro studies showed that such compounds decrease β-amyloid (Aβ) production by increasing the fluorescence signal emitted by Ltf in N2a-sw cells, and that they act by modulating the expression of amyloidogenic pathway-associated enzymes (BACE1 and APH1α). In addition, in vivo studies showed a concomitant reduction in the expression levels of amyloidogenic pathway-related enzymes (BACE1 or APH1α). Thus, computational studies have focused on Ltf interactions that may recommend drug repurposing strategies and options for AD. Show less

Alzheimer's disease (AD) is a multi-factorial neurodegenerative disorder. A crosstalk between AD and hyperglycaemia has been observed where patients showed increased insulin resistance. Type 2 diabetes mellitus and its features, including hyperinsulinemia and chronic hyperglycaemia with an inflammatory response, are related to AD through insulin resistance. Here, aim was to identify a phytocompound that could be used as a potential drug candidate. GC-MS analysis of Show less

The hallmark of Alzheimer's disease (AD), a progressive neurodegenerative condition, is the buildup of amyloid-beta (Aβ) plaque, which is mainly caused by β-secretase 1 (BACE-1) activity. BACE-1 inhibition is a potentially effective treatment strategy to lower the progression of AD. In order to find possible BACE-1 inhibitors using a drug repurposing technique, this study uses an integrated computational approach that includes pharmacophore modelling, virtual screening, molecular docking, MM-GBSA, molecular dynamics (MD) simulations, in-silico ADMET profiling, and PBPK modelling. A pharmacophore model, was created with known BACE-1 inhibitors to enable virtual screening of both novel and FDA-approved chemical libraries. Top candidates with good free energy scores and strong binding affinities were found using molecular docking and MM-GBSA calculations. The stability of shortlisted Hits inside the BACE-1 active site was further validated using MD simulations, which showed that some of the important interactions were maintained across a period of 50ns. ADMET and PBPK studies predicted favorable pharmacokinetic and safety profiles for the shortlisted hits, particularly for B2 and B9. These findings identify potential candidates for future experimental validation, offering an inexpensive approach for identification of compounds as potential BACE-1 inhibitors. Show less

Alzheimer's disease (AD) is a degenerative neurological disease characterized by a loss of memory and cognitive ability. One of the main factors influencing the development of AD is the accumulation of amyloid β (Aβ) plaque in the brain. The sequential production of Aβ is mediated by two enzymes: gamma-secretase and β-secretase (BACE1). The goal of beta-secretase inhibitors is to prevent the initial cleavage of amyloid precursor protein (APP), which reduces the production of (Aβ) peptides by limiting the substrate available for gamma-secretase. Simultaneously, gamma-secretase modulators are engineered to specifically modify enzyme performance, reducing the synthesis of the harmful Aβ42 isoform while maintaining vital physiological processes. Targeting both secretases reduces amyloidogenic processing synergistically. Selective inhibitors, which have been recently developed, have also shown good clinical development. They can reduce Aβ levels effectively with minimal side effects. The therapeutic strategy also underlines the importance of early therapy intervention in the preclinical AD phase for an optimum effect. Although there are some problems in the optimization of drug delivery and the alleviation of side effects, targeting beta and gamma secretases remains a promising direction. However, all these strategies still need more research and clinical testing to improve existing treatments and develop new, efficient Alzheimer's disease therapies. This review seeks to examine the therapeutic promise of β- and γ-secretase inhibition in Alzheimer's disease and review recent progress, challenges, and new dual-inhibition approaches. Show less

Alzheimer's disease (AD) is a complex neurodegenerative disorder characterized by cognitive decline, oxidative stress, neuroinflammation, amyloid-beta (Aβ) accumulation, and tau protein hyperphosphorylation. In this study, we synthesized novel Ramalin derivatives and evaluated their therapeutic potential against AD, focusing on antioxidant, anti-inflammatory, and neuroprotective activities. RA-2OMe, RA-4OMe, RA-2CF3, and RA-4OCF3 showed strong antioxidant effects, while RA-2OMe exhibited potent NO and NLRP3 inhibition (~20%). RA-NAP, RA-PYD, and RA-2Q showed moderate anti-inflammatory activity. BACE-1 inhibition was significant in RA-3CF3, RA-NAP, and RA-PYD, with IC Show less

To reveal the effects and potential mechanisms by which synaptic vesicle glycoprotein 2A (SV2A) influences the distribution of amyloid precursor protein (APP) in the trans-Golgi network (TGN), endolysosomal system, and cell membranes and to reveal the effects of SV2A on APP amyloid degradation. Colocalization analysis of APP with specific tagged proteins in the TGN, ensolysosomal system, and cell membrane was performed to explore the effects of SV2A on the intracellular transport of APP. APP, β-site amyloid precursor protein cleaving enzyme 1 (BACE1) expressions, and APP cleavage products levels were investigated to observe the effects of SV2A on APP amyloidogenic processing. APP localization was reduced in the TGN, early endosomes, late endosomes, and lysosomes, whereas it was increased in the recycling endosomes and cell membrane of SV2A-overexpressed neurons. Moreover, Arl5b (ADP-ribosylation factor 5b), a protein responsible for transporting APP from the TGN to early endosomes, was upregulated by SV2A. SV2A overexpression also decreased APP transport from the cell membrane to early endosomes by downregulating APP endocytosis. In addition, products of APP amyloid degradation, including sAPPβ, Aβ These results demonstrated that SV2A promotes APP transport from the TGN to early endosomes by upregulating Arl5b and promoting APP transport from early endosomes to recycling endosomes-cell membrane pathway, which slows APP amyloid degradation. Show less

Oxysterols, gut metabolites, and N6-methyladenosine (m6A) are extensively implicated in the pathogenesis of cognitive dysfunction, while their alterations in different stages of mild cognitive impairment (MCI) have not been elucidated. Therefore, this study was conducted to explore the associations of oxysterols, gut metabolites, and m6A methylation profiles in early MCI (EMCI) and late MCI (LMCI) individuals. Liquid chromatography-mass spectrometry, untargeted metabolomic analysis, and m6A mRNA Epitranscriptomic Microarray were used to detect the characteristics of serum oxysterols (n = 35/group), fecal gut metabolites (n = 30/group), and m6A in whole blood (n = 4/group) respectively. The concentration of serum β-amyloid (Aβ) was detected with ELISA (n = 25/group). The gene expression of amyloid precursor protein (APP) and its key enzyme β-secretase (BACE1) in whole blood were measured by quantitative real-time PCR (n = 25/group). EMCIs and LMCIs, especially LMCIs, exhibited poorer performance in almost all global and multidimensional cognitive tests. Serum 27-hydroxycholesterol (27-OHC) and 24S-hydroxycholesterol (24S-OHC) were elevated in EMCI and LMCI groups. Changes in gut metabolites occurred mainly in the EMCI group, in which several gut metabolites, including Procyanidin dimer B7 and Phorbol myristate, were significantly decreased. The m6A methylation landscape of EMCIs and LMCIs obviously differed from Controls. Hypomethylated mRNAs accounted for the majority and were mainly accompanied by downregulated mRNAs, which was consistent with the downregulated expression of the m6A writer methyltransferase-like 4 (METTL4). 27-OHC and 24S-OHC combined with various gut metabolites significantly distinguished between MCI subgroups from healthy controls (EMCI/Control: AUC = 0.877; LMCI/Control: AUC = 0.952). Heatmap revealed the correlation between Phorbol myristate and differentially m6A-methylated mRNAs. Differentially expressed gut metabolites and methylated mRNAs were commonly enriched in 34 KEGG metabolic pathways, including cholesterol metabolism and neurodegenerative disease-related pathways. Our study explored the altered oxysterols, gut metabolites, and m6A methylation and their associations in different stages of MCI. The potential function of aberrant gut metabolites in oxysterols and m6A methylation driving MCI progression warrants further mechanistic investigation. Show less

β-secretase 1 (BACE1), known for its role in amyloid-β production associated with Alzheimer's disease (AD), has also been suggested to be elevated in patients with Type 2 diabetes mellitus (T2DM). Notably, BACE1 could cleave the insulin receptor (InsR), leading to reduced InsR levels, which may impair insulin signaling and contribute to insulin resistance. Presently, we observed decreased InsR levels and impaired glucose disposal in the livers of mice with systemic overexpression of BACE1 (HUBC mice). This suggests that elevated BACE1 could contribute to insulin resistance by shedding membrane InsR. Additionally, mice fed a high-fat diet (HFD), a well-established model of T2DM, displayed increased BACE1 levels and decreased InsR. To further investigate whether inhibiting BACE1 could enhance insulin sensitivity and alleviate symptoms of diabetes, we treated HFD mice with the BACE1 inhibitor Elenbecestat. Remarkably, the administration of Elenbecestat restored InsR levels and improved their downstream signaling pathways, leading to increased insulin sensitivity and enhanced glucose tolerance. In summary, our findings suggest that inhibiting BACE1 can restore InsR expression and improve insulin-signaling sensitivity, ultimately resulting in enhanced diabetic phenotypes. Show less

Endosomal system dysfunction within neurons is a prominent early feature of Alzheimer's disease (AD) pathology. Multiple AD risk factors are regulators of endocytosis and known to cause hyperactivity of the early endosome small GTPase rab5, resulting in neuronal endosomal pathway disruption and cholinergic neurodegeneration. Adaptor protein containing Pleckstrin homology domain, Phosphotyrosine binding domain, Leucine zipper motif (APPL1), an important rab5 effector protein and signaling molecule has been shown in vitro to interface between endosomal and neuronal dysfunction through a rab5-activating interaction with the BACE1-generated C-terminal fragment of amyloid precursor protein (APP-βCTF), a pathogenic APP fragment generated within endosomal compartments. To understand the contribution of APPL1 to AD-related endosomal dysfunction in vivo, we generated a transgenic mouse model overexpressing human APPL1 within neurons (Thy1-APPL1). Strongly supporting the important endosomal regulatory roles of APPL1 and their relevance to AD etiology, Thy1-APPL1 mice (both sexes) develop enlarged neuronal early endosomes and increased synaptic endocytosis due to increased rab5 activation. We demonstrated pathophysiological consequences of APPL1 overexpression, including functional changes in hippocampal long-term potentiation (LTP) and long-term depression (LTD), degeneration of large projection cholinergic neurons of the basal forebrain, and impaired hippocampal-dependent memory. Our evidence shows that neuronal APPL1 elevation modeling its functional increase in the AD brain induces a cascade of AD-related pathological effects within neurons, including early endosome anomalies, synaptic dysfunction, and selective neurodegeneration. Our in vivo model highlights the contributions of APPL1 to the pathobiology and neuronal consequences of early endosomal pathway disruption and its potential value as a therapeutic target. Show less

Alzheimer's disease (AD) is a progressive neurodegenerative disorder affecting millions of people worldwide, with its prevalence expected to rise in the coming years. Due to the complexity of AD and the intricate interplay among its pathological mechanisms, the development of multitarget-directed ligands (MTDLs) has emerged as a promising therapeutic strategy. These compounds could simultaneously modulate multiple pathogenic pathways. Specifically, cholinergic and amyloid mechanisms, implicated in the onset of the disease, are regulated by AChE and BACE1, respectively. Therefore, targeting both pathways offers substantial therapeutic potential for AD. Computational tools can be useful in the identification of potential MTDL for these enzymes, reducing both costs and time in the drug discovery process. This review explores the relevance of this approach in the research and development for novel AD therapies, highlighting ongoing efforts focused on the identification and development of MTDLs for AChE and BACE1 inhibition through in silico methods. Virtual screening was the most frequently applied technique for a fast selection of ligands based on their affinity for the enzymes of interest. The in silico ADMET prediction also appears with a technique that allows the screening of compounds with drug-likeness. Moreover, evidence suggests that combining multiple computational methods can effectively identify drug candidates with optimized properties for target modulation and brain bioavailability. Show less

To explore the mechanism by which BALB/c mice were infected by intraperitoneal injection with TgCtwh3 wild type (TgCtwh3 WT) and TgCtwh3 Δ BALB/c mice injected with TgCtwh3 Δ Our results indicated that the GRA15 Show less

This study investigated the effects of periodontitis (P) and non-surgical periodontal therapy (NSPT) on behavior, neurodegeneration, and neuroinflammation in rats with Alzheimer's disease (AD)-like pathology. AD-like pathology was induced in rats (n = 28) using STZ neurodegeneration model. Periodontitis was experimentally induced (n = 32), and half of which received NSPT with Chlorhexidine (CHX) gel. Behavioral assessment included the passive avoidance task (PA) and Morris water maze (MWM). Levels of NLRP3, phosphorylated tau (p-tau), and tau in the hippocampus, cerebrospinal fluid (CSF), and serum were measured by ELISA, while BACE1, IL1β, iNOS, and NF-κβ proteins were assessed by Western blotting. Rats in the AD and AD + P groups performed worse in behavioral tests compared to controls (p < 0.05), whereas the NSPT group showed similar performance to controls (p > 0.05). CSF p-tau levels were comparable between AD and AD + P groups, but the hippocampal p-tau/tau ratio was significantly higher in the AD + P group (p < 0.05). BACE1 levels were similar in P and AD groups. NLRP3 and iNOS levels did not show significant differences across groups. Notably, the NSPT group exhibited reduced NF-κβ levels (p < 0.05). Periodontitis may exacerbate AD-like molecular pathology, particularly by promoting tau hyperphosphorylation, while NSPT appears to mitigate disease progression and improve behavioral outcomes. Show less

BackgroundAlzheimer's disease (AD) is the main cause of dementia in an aging society. Previous studies have demonstrated that non-invasive light flicker and sound with gamma frequency oscillations can modulate AD-related pathology in AD mice, potentially improving patient outcomes. However, the molecular mechanism by which sound with gamma frequency oscillations inhibits the expression of amyloid-β Show less

Behavioral Tagging (BT) is a well-established phenomenon under in vivo conditions to understand molecular framework of long-term memory (LTM) consolidation. BT has been extensively explored using different learning tasks and novelties at the behavioral level, while at the molecular level, handful of plasticity related proteins (PRPs) such as PKMζ, CREB, BDNF have been explored in various manners thereof. Hence, the quest for novel PRPs in BT becomes a necessity, since repeated studies of known PRPs results in scientific stagnation and cessation of further exploration. Emerging literature suggests potential role of BACE1 and endogenous Aβ in maintenance of synaptic plasticity and long-term potentiation. The present study aims to characterize the effects of BACE1 inhibition using minocycline on novel object recognition (NOR) LTM through environment enrichment (EE) mediated BT. BACE1 is responsible for endogenous Aβ generation, hence its inhibition also subdues the Aβ synthesis. Our results significantly demonstrate the active involvement of BACE1 and endogenous Aβ in facilitating NOR-LTM consolidation through EE mediated BT for the first time under in vivo conditions. Interestingly, EE exposure was found to induce the synthesis of BACE1 and endogenous Aβ in BT paradigm along with their potential interplay with PKMζ signaling to facilitate NOR-LTM consolidation. Taken together, our results provide first hand evidence of the role of BACE1 and endogenous Aβ as novel PRP complex in EE mediated BT phenomenon. The results provide significant advance in our understanding of LTM consolidation process and paves the way for exploration of novel molecular pathways involved in the process. Show less

The Gastrointestinal (GI) microbiome and gut-brain axis are associated with the progression and pathology of Alzheimer's disease (AD). Amyloid deposition is thought to be a driver of AD, causing synaptic dysfunction and neuronal death in the brain. Chronic constipation is a common gastrointestinal (GI) dysmotility in AD patients, which impacts patient outcomes and quality of life. It is unknown if enteric amyloidosis disrupts myenteric neuron function and causes GI dysmotility. Untreated male and female APP/PS1 (a transgenic murine model of brain amyloidosis) and sex-matched control mice were followed until 12 months of age. A separate cohort of mice was treated with a vehicle or the beta-secretase (BACE1) inhibitor, lanabecestat, starting at 5 months of age until 7 months. GI motility was assessed in all mice by measuring whole GI transit in vivo. Propulsive colonic motility and GI smooth muscle contractions were measured ex vivo. At 7 or 12 months old, amyloidosis in the brain and myenteric plexus was determined by immunohistochemistry or ELISA; the myenteric neural density, including the cholinergic and nitrergic neurons, was evaluated by immune staining and RT-PCR; expression of pro-inflammatory factors in the GI wall was assessed by RT-PCR. By 7 months of age, male and female APP/PS1 mice developed abundant amyloid plaques in the brain. Aged untreated male APP/PS1 mice also demonstrated Aβ deposition in the colonic myenteric ganglia, which was associated with increased fecal output and faster whole GI transit starting at 4-7 months old, but vehicle- and lanabecestat-treated male APP/PS1 mice had similar GI motility to their non-genetic controls until 7 months old. None of the female APP/PS1 mice showed GI dysmotility or myenteric amyloidosis. Two months of lanabecestat treatment effectively reduced amyloid plaque burden in the brains of female APP/PS1 mice but not in male APP/PS1 mice. Treatment with lanabecestat did not affect myenteric Aβ intensity or GI motility in all APP/PS1 mice. All APP/PS1 mice did not show myenteric neuronal degeneration or inflammation until 12 months old. APP/PS1 mice do not recapitulate myenteric amyloidosis persistently and lack the phenotype of constipation observed in human AD patients; these mice should not be considered an adequate murine model for studying the role of myenteric amyloidosis in GI dysmotility. An adequate animal model with myenteric amyloidosis is required for further study. Show less

This study aims to evaluate cognitive impairment utilizing the Montreal Cognitive Assessment (MoCA) scale, while also exploring the correlation between cognitive impairment and various serum biomarkers, including Brain-derived neurotrophic factor (BDNF), Beta Secretase-1 (BACE1), Vascular Endothelial Growth Factors (VEGF), Glial fibrillary acidic protein (GFAP), and Interleukin-1 (IL-1β) in adults living with epilepsy. In this study, 74 participants aged between 18 and 50 years, who were visiting neurology outpatient consultations, were included. The cognitive assessment was executed using the MoCA test. Serum levels of BDNF, BACE1, VEGF, GFAP, and IL-1β were evaluated through ELISA in patients with and without cognitive impairments. To determine the association between MoCA scores and the biomarkers, both Spearman and Pearson correlation analyses, as well as linear regression, were conducted. Among the 74 PWE, 61 exhibited cognitive impairment as determined by the MoCA assessment. Noteworthy alterations were detected across various MoCA subscales, encompassing visuospatial and executive functions, attention, language, abstraction, and delayed recall, with statistical significance established ( We conclude that adult PWE in India demonstrate a significant cognitive impairment. Further, our findings indicate that BDNF may serve as a potential biomarker for evaluating cognitive impairment in adult PWE. Further longitudinal, prospective and multi-center studies are required to confirm the same. Show less

Apolipoprotein E (ApoE) variants are central to Alzheimer's disease (AD), Lewy body dementia (LBD) and Niemann-Pick disease type C (NPC). The ApoE4 variant elevates AD risk by 3-15-fold. ApoE's normal function in lipid transport is known. The question remains how different ApoE isoforms cause cellular pathogenesis. We determined the effects of ApoE isoforms on lipid accumulation induced by inhibiting the endo-lysosomal cholesterol transporter NPC1. In human fibroblasts and astrocytes, NPC1 inhibition caused a 4-fold cholesterol accumulation and mis-localization with altered cholesterol sensing and increased synthesis of cholesterol and triglycerides. Total APP, APP C-terminal fragments (CTF) and BACE1 levels increased 3-fold. Remarkably, the intracellular neutral lipids co-localized with APP and APP C-terminal fragments. ApoE2 and ApoE3, but not ApoE4, reduced intracellular cholesterol levels by 67% and 62%, respectively, normalized APP, BACE, CTF, and improved cell survival. ApoE4 combined with a synthetic lipopeptide, which increased the proportion of large lipidated ApoE4 particles, corrected these abnormalities. This highlights ApoE in lipid pathogenesis and targeting ApoE4 lipidation to restore ApoE4 function. Show less

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline and memory loss, with amyloid-beta (Aβ) plaques and acetylcholine deficits being central pathological features. Inhibition of dual targets including acetylcholinesterase (AChE) and beta-site amyloid precursor protein cleaving enzyme 1 (BACE-1) represents a promising strategy to address cholinergic deficits and amyloid pathology. In this study, we used computational approaches to evaluate 8000 tripeptides as potential dual inhibitors of AChE and BACE-1. Machine learning models revealed the four top-lead tripeptides including WHM, HMW, WMH, and HWM. Molecular docking simulations indicated that WHM possessed the most favorable interactions through hydrogen bonds, π-π stacking, and salt bridges with key catalytic residues in both enzymes. Molecular dynamics simulations confirmed the stability of the protein-ligand complexes, with WHM exhibiting the most consistent conformations and significant disruption of catalytic residue geometries. Free energy perturbation analysis further supported WHM's superior stability across both targets. ADMET predictions suggested moderate oral absorption and limited brain penetration, consistent with the typical behavior of peptide-based compounds. Overall, WHM demonstrated the strongest potential as a dual inhibitor of AChE and BACE-1, offering a promising lead for future therapeutic development in AD. Show less

While several hypotheses have been proposed to explain the underlying mechanisms of Alzheimer's disease, none have been entirely satisfactory. Both genetic and non-genetic risk factors, such as infections, metabolic disorders and psychological stress, contribute to this debilitating disease. Multiple lines of evidence indicate that ceramides may be central to the pathogenesis of Alzheimer's disease. Tumor necrosis factor-α, saturated fatty acids and cortisol elevate the brain levels of ceramides, while genetic risk factors, such as mutations in APP, presenilin, TREM2 and APOE ε4, also elevate ceramide synthesis. Importantly, ceramides displace sphingomyelin and cholesterol from lipid raft-like membrane patches that connect the endoplasmic reticulum and mitochondria, disturbing mitochondrial oxidative phosphorylation and energy production. As a consequence, the flattening of lipid rafts alters the function of γ-secretase, leading to increased production of Aβ Show less

Proinflammatory cytokines, especially interleukin-17 A (IL-17 A) have been found to be significantly associated with AD patients. IL-17 A amplifies neuroinflammation during AD pathology. This study highlighted the ability of IL-17 A to exacerbate amyloid-beta-induced pathology in animals. The AD pathology was induced with repeated intranasal administration of Aβ along with recombinant mouse IL-17 A (rmIL-17) at 1, 2 and 4 µg/kg for seven alternate days. Although, the combination of rmIL-17 and Aβ did not have severe effects on memory of the animals, but it drastically increased the IL-17 A mediated signaling, level of proinflammatory cytokines, oxidative stress and reduced antioxidants in the hippocampus and cortex regions of the animal brains. Interestingly, combining rmIL-17 with Aβ also triggered the expression of AD structural markers like pTau, amyloid-beta and BACE1 in the brain regions. Furthermore, rmIL-17 with Aβ exposure stimulated astrocytes and microglia leading to activation of proinflammatory signaling in the brain of the animals. These results showed the propensity of IL-17 A to promote severity of AD pathology and suggest IL-17 A as potent therapeutic target to control AD progression. Show less

Amyloid cerebrovascular disease, primarily driven by the accumulation of amyloid-beta (Aβ) peptides, is intricately linked to neurodegenerative disorders like Alzheimer's disease. BACE1 (beta-site amyloid precursor protein cleaving enzyme 1) plays a critical role in the production of Aβ, making it a key therapeutic target. In the current work, a CNS library of ChemDiv database containing 44085 compounds was screened against the BACE1 protein. Initially, a structure-based pharmacophore hypothesis was constructed, followed by virtual screening, with the screened hits docked to the BACE1 protein to determine the optimal binding modes. The docking results were examined using the glide gscore and chemical interactions of the docked molecules. The cutoff value of -5 kcal/mol was used to select hits with high binding affinities. A total of seven hits were chosen based on the glide g score. Furthermore, the possible binding mechanisms of the docked ligands were investigated, and it was discovered that all seven selected ligands occupied the same site in the predicted binding pocket of protein. The bioactivity scores of the compounds demonstrated that the chosen compounds possess the features of lead compounds. The toxicity risks and ADMET features of the selected hits were anticipated, and four compounds, J032-0080, SC13-0774, V030-0915, and V006-5608 were chosen for stability analysis. The selected hits were extremely stable and strongly bound to the BACE1 pocket, and conformational changes caused by RMSD, RMSF, and protein-ligand interactions were assessed using MD modeling. Similarly, principal component analysis revealed a large static number of hydrogen bonds. The MM/GBSA binding free energies maps revealed a significant energy contribution in the binding of selected hits to BACE1. The binding free energy landscapes indicated that the hits were bound with a high binding affinity. Thus, the hits could serve as lead compounds in biophysical investigations to limit the biological activity of the BACE1 protein. Show less