Search Results (45)

Background/Objectives: Protein–carbohydrate interactions are implicated in amyloid aggregation pathways associated with Alzheimer’s disease (AD). Designing glycomimetics that modulate amyloid assembly represents a promising strategy. In addition, the interaction of Aβ_1–42 oligomers (Aβo) with prion protein (PrP^C) activates Fyn kinase and leads to Tau hyperphosphorylation, another process characterizing AD. Thus, we generated a library of phenyl 2-acetamidoselenogalactoside mimetics to evaluate their interactions with Aβo and disruption of Aβo–PrP^C binding, and consequently their potential to inhibit Fyn kinase activation. Methods: The synthetic approach comprised azidophenylselenylation, a modified one-pot Staudinger reduction–acylation, a selective α-glycosylation, and deacetylation. Structural diversity was achieved mainly via acylation or ureation. The compounds were screened for binding to Aβo using STD-NMR, ¹⁹F-NMR, and rapid equilibrium dialysis (RED). ADME properties were assessed through microsomal metabolism and solubility assays, while cytotoxicity was evaluated by MTT assays in human embryonic kidney (HEK) cells. Results: Several compounds bound Aβo in STD-NMR experiments, mainly through aromatic and anomeric protons, and phenyl 2-deoxy-2-phenylureido-1-seleno-α-d-galactopyranoside (34) showed the most consistent response, with >50% increase in relative binding signal in competition assays, demonstrating also some inhibition of Aβo–PrP^C interactions (12%). Selenium at the anomeric position enhanced binding compared to sulphur and oxygen analogs. RED experiments confirmed weak binding interactions, consistent with STD-NMR results. ADME revealed that acetylated compounds undergo microsomal metabolism, whereas deacetylated derivatives displayed high aqueous solubility (>100 μM) and showed no cytotoxicity. Conclusions: Phenyl 2-acetamidoselenogalactosides are a novel class of amyloid-binding glycomimetics. Among them, 34 emerges as the most promising compound, combining favorable solubility, metabolic stability, low toxicity, and measurable interference with Aβo and Aβo–PrP^C interactions, thus supporting further developments toward therapeutic applications in AD. Full article

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by memory loss and cognitive decline. Its main pathological features are extracellular plaques composed of aggregated amyloid-β (Aβ) peptides and intracellular neurofibrillary tangles formed by hyperphosphorylated tau. The Aβ hypothesis proposes that Aβ accumulation is a key driver of AD, influencing tau pathology, neuroinflammation, and neurodegeneration. However, therapies that reduce Aβ have shown limited clinical benefits. This suggests that the mechanisms underlying peptide-mediated modulation of AD pathology are much more complex. Both Aβ and tau undergo various post-translational modifications (PTMs) that affect their structure, aggregation, and toxicity. In addition, these abnormal proteins are not efficiently cleared in AD, indicating dysfunction of the protein quality control (PQC) system that maintains proteostasis. Such abnormal PTMs and impaired PQC likely work together to drive disease progression, which may explain the limited success of Aβ-reduction therapies. In this review, we describe how major PTMs, including phosphorylation, ubiquitination, acetylation, glycosylation, and oxidation, regulate the pathological behavior of Aβ and tau. We also discuss the role of the PQC systems in the pathology of AD. We propose that dysregulation of PTMs and PQC constitutes a convergent mechanism underlying AD pathogenesis. Therapeutic strategies targeting these processes may provide more effective and sustained disease modification than approaches focused solely on Aβ reduction. Full article

Nitric oxide (NO) plays an important role in neuronal communication, synaptic plasticity and vascular regulation. Due to its important function in neuronal homeostasis, NO imbalance is associated with neurodegeneration. Specifically, in Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS), Parkinson’s disease (PD) and frontotemporal lobar degeneration (FTLD), an excessive amount of NO, mostly produced by inducible NO synthase (iNOS), reacts with superoxide to form peroxynitrite, driving oxidative/nitrosative stress, mitochondrial dysfunction, and aberrant protein modifications. In AD, NO dysregulation promotes amyloid-β (Aβ) accumulation, tau hyperphosphorylation and synaptic loss, creating a self-perpetuating cycle of neuronal damage. NO’s dual role, protective at physiological levels but harmful if overproduced, underscores the therapeutic potential of antioxidant compounds that restore the balance of NO/NOS (especially iNOS) while preserving physiological functions. However, despite the emerging role of antioxidant-based therapeutic approaches, clinical translation is limited by the complexity of NO signaling and the absence of safe, specific NOS inhibitors. By targeting the molecular switch from protective to toxic, NO activity may offer new personalized treatment avenues for neurodegenerative diseases. Full article

Alzheimer’s (AD) and Parkinson’s disease (PD) are prominent neurodegenerative disorders characterized by early synaptic loss, which correlates more closely with clinical symptoms than neuronal death. This synaptic impairment is primarily driven by disruptions in synaptic vesicle (SV) trafficking, a critical process for maintaining synaptic integrity through a tightly regulated cycle involving clustering, docking-priming, Ca²⁺-triggered fusion, and endocytosis. In AD, amyloid-β (Aβ) oligomers interfere with SNARE-mediated fusion and endocytosis, while hyperphosphorylated tau obstructs vesicle mobility and docking, resulting in cumulative toxicity that aggravates SV defects. Conversely, in PD, α-synuclein (α-syn) aggregation alters vesicle clustering, membrane fusion, and recycling, and these effects are further influenced by Leucine-rich repeat kinase 2 (LRRK2)-Rab-related trafficking defects and the selective vulnerability of dopaminergic terminals. Different from previous reviews that address synaptic dysfunction in a broader manner, the present review is specifically organized around the SV trafficking cycle and compares both shared presynaptic endpoints and disease-specific upstream mechanisms in AD and PD. In addition, recent mechanism-oriented therapeutic strategies are summarized. This vesicle-cycle-centered perspective may provide a clearer framework for understanding presynaptic pathology and for guiding the development of earlier and more targeted interventions. Full article

Type 2 Diabetes (T2D) is characterized by the toxic aggregation of human islet amyloid polypeptide (hIAPP or amylin) within pancreatic β-cells. IAPP is also a neuropancreatic hormone that plays a significant role in Alzheimer’s disease (AD) by co-depositing with amyloid-beta (Aβ) and Tau, supporting the Type 3 Diabetes (T3D) hypothesis. Soluble IAPP accelerates Aβ aggregation through cross-seeding and causes neurotoxicity by impairing the blood–brain barrier and activating neuroinflammation. Melatonin inhibits these processes by disrupting hydrophobic interactions in both hIAPP and Aβ, preventing the formation of toxic β-sheet structures. Furthermore, melatonin promotes amyloid clearance via the glymphatic and lymphatic systems, protects neurons from oxidative damage, and reduces Tau hyperphosphorylation. This suggests that melatonin serves as a promising multitarget therapeutic agent for both metabolic and neurodegenerative disorders by modulating structural protein transformations. Full article

Alzheimer’s disease (AD) is a catastrophic neurodegenerative disorder marked by progressive decline of cognitive function, memory loss, and neuronal death. Its pathology is characterized by the formation of extracellular amyloid-beta (Aβ) plaques and intracellular neurofibrillary tangles from tau hyperphosphorylation. Despite extensive research, current treatments are limited to symptomatic relief and are associated with significant side effects. This accentuates the critical need for alternative therapeutic strategies with potent neuroprotective effects and minimal toxicity. This study investigates the neuroprotective potential of glycyrrhizic acid, as the precise molecular mechanisms by which it might improve AD pathology remain poorly understood. Using an Aβ₄₂-induced IMR-32 cell model of AD, our research revealed that Aβ₄₂ treatment caused significant protein alterations associated with AD pathology, mitochondrial dysfunction, cell cycle re-entry, and synaptic activity. Co-treatment with glycyrrhizic acid not only restored these protein levels, but also mitigated the hyperactivation of several key signaling pathways and rescued neurons from apoptosis. These findings suggest that glycyrrhizic acid exerts neuroprotective effects by preventing mitochondrial dysfunction and apoptosis via modulation of critical signaling pathways. This study provides strong evidence for glycyrrhizic acid’s neuroprotective properties in AD, paving the way for further research into its potential as a promising therapeutic agent for Alzheimer’s disease. Full article

Oligodendrocytes (OLs) constitute the main glial population in the central nervous system and are indispensable for the stability and performance of neural networks. Although best known for generating and maintaining myelin to speed impulse conduction, their influence extends further. By modulating myelin in response to activity, supplying metabolic substrates, and engaging in neuroimmune communication, OLs help preserve the structural integrity and plasticity of neuronal circuits. Growing evidence now positions defective OLs as central players in Alzheimer’s disease (AD). Experimental work suggests that OL injury can act as an early trigger, fostering amyloid-β (Aβ) deposition and Tau hyperphosphorylation. Conversely, toxic Aβ aggregates and pathological Tau proteins damage OLs, causing myelin breakdown and progressive neurodegeneration that fuels a self-perpetuating cycle. Here, we synthesize current knowledge of OL physiology and its multifaceted contributions to AD pathogenesis, with particular attention to the bidirectional interplay between OL dysfunction and the disease’s core features—Aβ and tau. On this basis, we outline prospective therapeutic avenues to protect or restore oligodendrocyte function in AD. Full article

Background: The accumulation of β-amyloid plaques, neurofibrillary tangles, and neuroinflammation are key hallmarks of Alzheimer’s disease (AD). Reactive oxygen species (ROS) act as major triggers and amplifiers of neuroinflammatory responses, contributing to immune dysregulation and neuronal damage. Despite extensive research, no effective therapy halts or reverses AD progression, emphasizing the need for alternative preventive strategies, including the use of natural compounds. Objectives: This study evaluated the neuroprotective effects of simulated digestive fractions (permeate fraction) of mushroom biomass (MB)—Trametes versicolor (TV), Hericium erinaceus (HE), and Pleurotus ostreatus (PO)—and key gut microbiota-derived metabolites, such as short-chain fatty acids (SCFAs) and γ-aminobutyric acid (GABA) on ROS production in human microglial cells (HMC3) and in transgenic Caenorhabditis elegans models exhibiting hyperphosphorylated Tau and β-amyloid-induced toxicity. Methods: Cell viability and ROS production were assessed in HMC3 cells treated with mushroom fractions and metabolites. Chemotaxis and paralysis assays were performed in transgenic C. elegans strains expressing hyperphosphorylated Tau or β-amyloid proteins. Results: Mushroom digestive fractions and SCFAs significantly decreased ROS levels in HMC3 cells. Moreover, mushroom digestive fractions, butyric acid, and GABA improved behavioral outcomes in C. elegans, enhancing chemotaxis and delaying paralysis. These effects were dose-dependent and varied among mushroom species and metabolites. Conclusions: Mushroom-derived digestive fractions and microbiota-related metabolites exhibit neuroprotective activity by modulating oxidative stress and mitigating neurodegeneration-associated behaviors. Diets enriched with such MBs may support preventive strategies for neurodegenerative diseases. Further research is required to elucidate the molecular mechanisms underlying these protective effects and their translational potential for human neurodegenerative diseases. Full article

Alzheimer’s disease (AD) is an age-related neurodegenerative disorder, characterised by the build-up of amyloid beta (Aβ) plaques and neurofibrillary tangles comprising hyper-phosphorylated tau. Increasing evidence indicates that in the early stages of AD, elevated levels of oligomeric forms of Aβ and phosphorylated tau (p-tau) gives rise to impaired synaptic function which ultimately drives AD-associated cognitive abnormalities. Thus, developing drugs that can limit the synaptic impairments that occur early in AD may have therapeutic benefits. Clinical evidence increasingly supports a link between lifestyle choices and AD risk. Indeed, there is an association between the circulating levels of the metabolic hormone leptin, mid-life obesity and disease risk, which has in turn stimulated interest in targeting the leptin system to treat AD. It is well-established that leptin readily accesses the brain, with the hippocampus, a key region that degenerates in AD, identified as a prime target for this hormone. Within the hippocampus, leptin has cognitive enhancing properties as it markedly influences the cellular events underlying hippocampal-dependent learning and memory, with significant impact on synaptic plasticity and trafficking of glutamate receptors at hippocampal excitatory CA1 synapses. Moreover, studies using a range of cell-based systems and animal models of disease indicate not only that leptin has powerful pro-cognitive effects, but also that leptin protects against the unwanted synapto-toxic effects of Aβ and tau, as well as enhancing neuronal cell viability. Moreover, recent studies have demonstrated that smaller leptin-based molecules replicate the full repertoire of protective features of whole leptin. Here we review the evidence that the leptin system is a potential novel avenue for drug discovery in AD. Full article

Background/Objectives: Glycogen synthase kinase-3 beta (GSK3β) is a key enzyme involved in neurodegenerative diseases such as Alzheimer’s and Parkinson’s, contributing to tau hyperphosphorylation, amyloid-beta (Aβ) aggregation, and neuronal dysfunction. Methods: This study applied a machine learning-driven virtual screening approach to identify potent natural inhibitors of GSK3β. A dataset of 3092 natural compounds was analyzed using Support Vector Machine (SVM), Random Forest (RF), and K-Nearest Neighbors (KNN), with feature selection focusing on key molecular descriptors, including lipophilicity (ALogP: −0.5 to 5.0), hydrogen bond acceptors (0–10), and McGowan volume (0.5–2.5). RF outperformed SVM and KNN, achieving the highest test accuracy (83.6%), specificity (87%), and lowest RMSE (0.3214). Results: Virtual screening using AutoDock Vina and molecular dynamics simulations (100 ns, GROMACS 2022) identified artemisinin as the top GSK3β inhibitor, with a binding affinity of −8.6 kcal/mol, interacting with key residues ASP200, CYS199, and LEU188. Dihydroartemisinin exhibited a binding affinity of −8.3 kcal/mol, reinforcing its neuroprotective potential. Pharmacokinetic predictions confirmed favorable drug-likeness (TPSA: 26.3–70.67 Ų) and non-toxicity. Conclusions: While these findings highlight artemisinin-based inhibitors as promising candidates, experimental validation and structural optimization are needed for clinical application. This study demonstrates the effectiveness of machine learning and computational screening in accelerating neurodegenerative drug discovery. Full article

Alzheimer’s disease (AD) is characterized by oxidative stress, amyloid-beta (Aβ) deposition, and tau hyperphosphorylation. While polysaccharides have demonstrated anti-AD effects, the properties of Cremastra appendiculata polysaccharides (CAPs) remain underexplored. This study evaluates the physicochemical properties, antioxidant activity, anti-AD effects, and underlying mechanisms of CAP in vitro and in Caenorhabditis elegans (C. elegans) AD models. CAP, containing 22.37% uronic acid, is stable below 270 °C and adopts a triple helix structure. Scanning electron microscopy (SEM) reveals an irregular layered architecture. In vitro, CAP exhibits significant antioxidant activity, protecting PC12 cells from Aβ-induced cytotoxicity. In C. elegans, CAP extends the lifespan in a concentration-dependent manner without affecting growth, alleviating tau-induced locomotor defects, reducing Aβ-induced paralysis and serotonin hypersensitivity, and decreasing Aβ deposition by 79.96% at 2.0 mg/mL. CAP enhances antioxidant capacity and heat resistance by reducing reactive oxygen species (ROS) levels and increasing glutathione S-transferase 4 (GST-4) and glutathione peroxidase (GSH-Px) activities. Additionally, CAP upregulates key genes in the insulin/insulin-like growth factor signaling pathway, including daf-16 and skn-1, along with their downstream targets (sod-3, ctl-1, gst-4, hsp-70). These findings suggest that CAP has potent antioxidant and anti-AD effects, alleviating Aβ- and tau-induced toxicity, and may serve as a promising therapeutic agent for Alzheimer’s disease. Full article

Alzheimer’s disease (AD) is the most common cause of dementia worldwide. Pathological deposits of neurotoxin proteins within the brain, such as amyloid-β and hyperphosphorylated tau tangles, are prominent features in AD. The prion protein (PrP) is involved in neurodegeneration via its conversion from the normal cellular form (PrPC) to the infection prion protein scrapie (PrPSc) form. Some studies indicated that post-translationally modified PrPC isoforms play a fundamental role in AD pathological progression. Several studies have shown that the interaction of Aβ oligomers (Aβos) with the N-terminal residues of the PrPC protein region appears critical for neuronal toxicity. PrPC-Aβ binding always occurs in AD brains and is never detected in non-demented controls, and the binding of Aβ aggregates to PrPC is restricted to the N-terminus of PrPC. In this study, we aimed to gather all of the recent information about the connections between PrPC and AD, with potential clinical implications. Full article

Amyloid plays a critical role in the pathogenesis of Alzheimer’s disease (AD) and can aggregate to form oligomers and fibrils in the brain. There is increasing evidence that highly toxic amyloid-β oligomers (AβOs) lead to tau protein aggregation, hyperphosphorylation, neuroinflammation, neuronal loss, synaptic loss, and dysfunction. Although the effects of AβOs on neurons have been investigated using conventional biochemical experiments, there are no established criteria for electrical evaluation. To this end, we explored electrophysiological changes in mouse hippocampal neurons (HT22) following exposure to AβOs and/or naringenin (Nar, a flavonoid compound) using electrical impedance spectroscopy (EIS). AβO-induced HT22 showed a decreased impedance amplitude and increased phase angle, and the addition of Nar reversed these changes. The characteristic frequency was markedly increased with AβO exposure, which was also reversed by Nar. The AβOs decreased intranuclear and cytoplasmic resistance and increased nucleus resistance and extracellular capacitance. Overall, the innovative construction of the eight-element CPE-equivalent circuit model further reflects that the pseudo-capacitance of the cell membrane and cell nucleus was increased in the AβO-induced group. This study conclusively revealed that AβOs induce cytotoxic effects by disrupting the resistance characteristics of unit membranes. The results further support that EIS is an effective technique for evaluating AβO-induced neuronal damage and microscopic electrical distinctions in the sub-microscopic structure of reactive cells. Full article

Alzheimer’s disease (AD) is a multi-stage neurodegenerative disorder characterized by beta-amyloid accumulation, hyperphosphorylated Tau deposits, neurodegeneration, neuroinflammation, and cognitive impairment. Recent studies implicate CD8 T cells as neuroimmune responders to the accumulation of AD pathology in the brain and potential contributors to toxic neuroinflammation. However, more evidence is needed to understand lymphocytes in disease, including their functional states, molecular mediators, and interacting cell types in diseased brain tissue. The scarcity of lymphocytes in brain tissue samples has limited the unbiased profiling of disease-associated cell types, cell states, drug targets, and relationships to common AD genetic risk variants based on transcriptomic analyses. However, using recent large-scale, high-quality single-nuclear sequencing datasets from over 84 Alzheimer’s disease and control cases, we leverage single-nuclear RNAseq data from 800 lymphocytes collected from 70 individuals to complete unbiased molecular profiling. We demonstrate that effector memory CD8 T cells are the major lymphocyte subclass enriched in the brain tissues of individuals with AD dementia. We define disease-enriched interactions involving CD8 T cells and multiple brain cell subclasses including two distinct microglial disease states that correlate, respectively, to beta-amyloid and tau pathology. We find that beta-amyloid-associated microglia are a major hub of multicellular cross-talk gained in disease, including interactions involving both vulnerable neuronal subtypes and CD8 T cells. We reproduce prior reports that amyloid-response microglia are depleted in APOE4 carriers. Overall, these human-based studies provide additional support for the potential relevance of effector memory CD8 T cells as a lymphocyte population of interest in AD dementia and provide new candidate interacting partners and drug targets for further functional study. Full article

Alzheimer’s disease (AD) is characterized by progressive accumulations of extracellular amyloid-beta (Aβ) aggregates from soluble oligomers to insoluble plaques and hyperphosphorylated intraneuronal tau, also from soluble oligomers to insoluble neurofibrillary tangles (NFTs). Tau and Aβ complexes spread from the entorhinal cortex of the brain to interconnected regions, where they bind pattern recognition receptors on microglia and astroglia to trigger inflammation and neurotoxicity that ultimately lead to neurodegeneration and clinical AD. Systemic inflammation is initiated by Aβ’s egress into the circulation, which may be secondary to microglial activation and can confer both destructive and reparative actions. Microglial activation pathways and downstream drivers of Aβ/NFT neurotoxicity, including inflammatory regulators, are primary targets for AD therapy. Osteopontin (OPN), an inflammatory cytokine and biomarker of AD, is implicated in Aβ clearance and toxicity, microglial activation, and inflammation, and is considered to be a potential therapeutic target. Here, using the most relevant works from the literature, we review and contextualize the evidence for a central role of OPN and associated inflammation in AD. Full article