Search Results (235)

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by memory loss, cognitive decline, and oxidative stress-driven neuronal damage. Catalase, a key antioxidant enzyme, plays a vital role in decomposing hydrogen peroxide (H₂O₂) into water and oxygen, thereby protecting neurons from reactive oxygen species (ROS)-mediated toxicity. In AD, the catalase function is compromised due to reduced enzymatic activity and aggregation, which not only diminishes its protective role but also contributes to amyloid plaque formation through catalase-Aβ co-oligomers. Hence, therapeutic strategies aimed at simultaneously preventing catalase aggregation and enhancing its enzymatic function are of great interest. In this study, we screened twelve naturally occurring metabolites for their ability to modulate catalase aggregation and activity. Among these, dimethylglycine (DMG) emerged as the most potent candidate. DMG significantly inhibited thermally induced aggregation of catalase and markedly enhanced its enzymatic activity in a concentration-dependent manner. Biophysical analyses revealed that DMG stabilizes catalase by promoting its native folded conformation, as evidenced by increased melting temperature (T_m), higher Gibbs free energy of unfolding (ΔG°), and reduced exposure of hydrophobic residues. TEM imaging and Thioflavin T assays further confirmed that DMG prevented amyloid-like fibril formation. Molecular docking and dynamics simulations indicated that DMG binds to an allosteric site on catalase, providing a structural basis for its dual role in stabilization and activation. These findings highlight DMG as a promising therapeutic molecule for restoring catalase function and mitigating oxidative stress in AD. By maintaining catalase stability and activity, DMG offers potential for slowing AD progression. Full article

Alzheimer’s disease (AD) is a worldwide problem due to the lack of effective therapy and accurate methods for timely diagnosis. The complexity of AD’s pathophysiology complicates the development of effective therapeutic agents, as most drugs act on only one therapeutic target, bypassing others. The design and development of multifunctional agents capable of altering metal ion-induced abnormalities, oxidative stress, and toxic beta amyloid (Aβ) aggregates is of interest. Herein, we report the first boron dipyrromethene (BODIPY) based bifunctional copper chelator with clioquinol, BDP-CLQ, capable of both optical detection of Aβ fibrils and copper chelation, with multiple anti-AD properties. Foremost, BDP-CLQ demonstrated a 3-fold and 5-fold fluorescence increase at 650 nm and 565 nm in the presence of Aβ and effective copper chelation (pK_d = 16.6 ± 0.3). In addition, BDP-CLQ demonstrated a potent inhibition of Aβ aggregation, reduction in Aβ-induced stiffness of neuronal cells, and antioxidant activity. BDP-CLQ is the first BODIPY-based fluorescent probe with multiple anti-AD activities, as well as the first clioquinol-based probe capable of Aβ optical visualization. This study demonstrates the prospects of the development of clioquinol-based theranostic probes since this allows combining several promising anti-AD actions in a single molecule and developing multi-targeted drugs. Full article

Alzheimer’s disease (AD) signifies a devastating impact on the quality of life of patients and their families. At a biomolecular level, AD is characterized by the deposition of extracellular plaques of β-amyloid (Aβ), affecting language, spatial navigation, recognition abilities and memory. Among the selected 30 articles about polyoxometalates (POMs) and AD published from 2011 to 2025, pure POMs, hybrid POMs and POM nanoparticles can be found. The majority of POMs are polyoxotungstates (62%), the Keggin-type SiW₁₁O₃₉ being the most studied in AD. The main effect described is the inhibition of Aβ aggregates. Other effects include reversing the neurotoxicity induced by Aβ aggregates, decreasing ROS production and neuroinflammation, restoring memory and sequestering Zn²⁺ and Cu²⁺, among others, features that are well known to be associated with the pathology of AD. POMs have also shown the ability to induce the disaggregation of Aβ fibrils, particularly after irradiation, and to inhibit acetylcholinesterase activity at an nM range. Putting it all together, this review highlights a predominant trend in the exploration of POMs to act directly at the level of the formation and/or disaggregation of Aβ aggregates in the treatment of AD. Full article

Alzheimer’s disease is driven by multiple molecular drivers, including the pathological behavior of two intrinsically disordered proteins, amyloid-β (Aβ) and tau, whose aggregation is regulated by sequence-encoded ensembles and liquid–liquid phase separation (LLPS). This review integrates recent advances in biophysics, structural biology, and computational modeling to provide a multiscale perspective on how sequence determinants, post-translational modifications, and protein dynamics regulate the conformational landscapes of Aβ and tau. We discuss sequence-to-ensemble principles, from charge patterning and aromatic binders to familial mutations that reprogram structural ensembles and modulate LLPS. Structural studies, including NMR, SAXS, cryo-EM, and cryo-electron tomography, trace transitions from disordered monomers to fibrils and tissue-level structures. We highlight experimental challenges in LLPS assays, emerging standards for reproducibility, e.g., LLPSDB, PhaSePro, and FUS benchmarks, and computational strategies to refine and condensate modeling. Finally, we explore the therapeutic implications, including condensate-aware medicinal chemistry, ensemble-driven docking, and novel insights from clinical trials of anti-Aβ antibodies. Together, these perspectives underscore a paradigm shift toward environment- and ensemble-aware therapeutic design for Alzheimer’s and related protein condensation disorders. Full article

Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by memory loss and cognitive decline, primarily due to amyloid β (Aβ) aggregation in the brain. Astaxanthin (AxN), a xanthophyll carotenoid derived from Haematococcus pluvialis, possesses antioxidant and neuroprotective properties. This study investigated the neuroprotective effects of AxN against Aβ aggregation in human neuroblastoma SH-SY5Y cells. Initially, AxN inhibited Aβ aggregation in DMEM/F12 culture medium but not in PBS, suggesting a medium-dependent effect. Using quantum dot nanoprobes, Aβ aggregation was visualized in the presence of SH-SY5Y cells. AxN treatment (0.032–20 µM) significantly reduced Aβ aggregation and accumulation on SH-SY5Y cells. AxN also prevented Aβ-induced early apoptotic cell death but was less effective against late necrosis. Furthermore, a wound-healing assay showed that AxN restored the impaired cell motility caused by Aβ aggregation. Thioflavin T staining confirmed the reduction in Aβ fibril formation around the cells following AxN treatment. In conclusion, our study suggests that AxN prevents Aβ aggregation and accumulation on the cell surface, thereby restoring cell motility and preventing early apoptosis in neuronal cells. Full article

Background: Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by the accumulation of amyloid-β (Aβ) plaques and hyperphosphorylated tau tangles, which synergistically accelerate disease progression. Since Aβ plaques and tau tangles are key factors in the development of AD, dual-targeting of Aβ and tau aggregation represents a promising therapeutic strategy. Amodiaquine (AQ), a quinoline-based antimalarial, has recently attracted attention for its ability to suppress protein aggregation. However, direct effects of AQ on both Aβ and tau aggregation remain unclear. Methods: The effects of AQ on the aggregation and dissociation of Aβ and tau were examined using a thioflavin T (ThT) assays. Molecular docking and molecular dynamics (MD) simulations were performed to examine binding characteristics and structural interactions. The effects of AQ on the expression of pro-inflammatory cytokines induced by Aβ and tau aggregation in BV2 microglial cells were analyzed by qRT-PCR. Results: ThT assay demonstrated a dose-dependent dual effect of AQ on Aβ, where 25 μM inhibited aggregation after 36 h, while 250 μM markedly accelerated it, reaching a plateau within 12 h. All concentrations of AQ promoted the disassembly of mature Aβ fibrils within 12 h. Molecular docking revealed stronger binding of AQ to aggregated Aβ (−45.17 and −23.32 kcal/mol for pentameric 2BEG and hexameric 2NAO) than to monomeric Aβ (−4.81 and −7.29 kcal/mol for 1Z0Q and 2BEG). MD simulation suggested that AQ disrupted the cross-β-sheet interactions of Aβ aggregates. In the case of tau, ThT assay showed that all concentrations of AQ inhibited tau aggregation from 6 h, and 350 μM AQ promoted the disassembly of mature fibrils from 6 h. Molecular docking indicated stronger binding of AQ to aggregated tau (−27.95 and −12.13 kcal/mol for the pentameric and decameric 5O3L) than to monomeric tau (−3.05 kcal/mol for 8Q96). MD simulations revealed no major structural changes in the aggregates. In BV2 cells, 1 and 10 μM AQ significantly reduced Aβ and tau-induced TNF-α and IL-6 mRNA expressions. In APP-H4 cells, 10 μM AQ decreased the level of Aβ compared to the control. Conclusions: AQ modulates both Aβ and tau aggregation and attenuates neuroinflammation and reduces Aβ pathology, supporting its potential as a dual-target therapeutic candidate for AD. Full article

Alzheimer’s disease (AD) has been studied extensively and is characterized by plaques deposited throughout the brain. Plaques are made of beta-amyloid (Aβ) peptides which have undergone fibrillogenesis to form insoluble Aβ fibrils (fAβ) that are neurotoxic. Receptor for Advanced Glycation End end products (RAGE), toll-like receptors (TLRs) 2 and 4, and co-receptor CD14 recognize negatively charged binding regions on fAβ to activate microglia and release proinflammatory cytokines. In this study, we used two experimentally resolved fAβ structures (type I and II) isolated from AD brain tissue to elucidate binding patterns of fAβ with RAGE, TLR2, TLR4, and CD14 and investigated whether binding was affected by fibril structure or system pH. Receptors TLR2 and RAGE formed tight complexes with both type I and II fibrils, while TLR4 showed selectivity for type I. CD14 binding was less tight and selective for type II. Binding was pH dependent for CD14, TLR4, and RAGE but not TLR2. We explored the effects of familial mutations on fibril structure to determine whether mutants of type I or II structures are feasible. Finally, we investigated whether mutations affected binding interactions of fAβ with proteins. The Arctic (Glu22Gly), Dutch (Glu22Gln), and Iowa (Asp23Asn) mutations showed similar effects on binding affinity. Italian (Glu22Lys) mutations abrogated binding, whereas type I and II fibrils with Flemish (Ala21Gly) mutations were not shown to be feasible. Results highlight the adaptability of immune receptors in recognizing damaging molecules, with fibril structure and pH being the main recognition determinants predicated on disease progression. In silico mutations showed that aggregates similar to type I and II structures were plausible for some familial mutations. Full article

The development of positron emission tomography (PET) tracers targeting α-synuclein (α-syn) aggregates is critical for the early diagnosis, differential classification, and therapeutic monitoring of synucleinopathies such as Parkinson’s disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy. Despite recent advances, challenges including the low abundance of α-syn aggregates (10–50× lower than amyloid-beta (Aβ) or Tau), structural heterogeneity (e.g., flat fibrils in PD vs. cylindrical forms in DLB), co-pathology with Aβ/Tau, and poor metabolic stability have hindered PET tracer development for this target. To optimize our previously reported pyridothiophene-based radiotracer, [¹⁸F]asyn-44, we present the synthesis and evaluation of novel S,N-heterocyclic scaffold derivatives for α-syn. A library of 49 compounds was synthesized, with 8 potent derivatives (LMD-006, LMD-022, LMD-029, LMD-044, LMD-045, LMD-046, LMD-051, and LMD-052) demonstrating equilibrium inhibition constants (K_i) of 6–16 nM in PD brain homogenates, all of which are amenable for radiolabeling with fluorine-18. This work advances the molecular toolkit for synucleinopathies and provides a roadmap for overcoming barriers in PET tracer development, with lead compounds that can be considered for biomarker-guided clinical trials and targeted therapies. Full article

Alzheimer’s disease (AD) is the most common form of dementia, characterized by progressive memory loss and cognitive decline. Its key pathological hallmarks include extracellular amyloid plaques composed of amyloid beta (Aβ) peptides and intracellular neurofibrillary tangles formed by hyperphosphorylated tau protein. Although numerous studies have investigated the complex pathology of AD, its underlying mechanisms remain incompletely understood. The amyloid cascade hypothesis continues to be the leading model of AD pathogenesis. It suggests that Aβ aggregation is the initial trigger of neurotoxicity, setting off a cascade of pathological events including inflammation, oxidative stress, tau hyperphosphorylation, synaptic dysfunction, and, ultimately, dementia. Molecular dynamics (MD) is a powerful tool in structure-based drug design (SBDD). By simulating biomolecular motions at the atomic level, MD provides unique insights into molecular properties, functions, and inhibition mechanisms—insights often inaccessible through other experimental or computational techniques. When integrated with experimental data, MD further deepens our understanding of molecular interactions and biological processes. Natural compounds, known for their pleiotropic pharmacological activities, favorable safety profiles, and general tolerability (despite occasional side effects), are increasingly explored for their potential in both the treatment and prevention of various diseases, including AD. In this review, we summarize current findings from MD simulations of natural compounds with anti-amyloidogenic potential. This work builds upon our previous publication, which focused on endogenous compounds and repurposed drugs. The review is structured as follows: an overview of the amyloid cascade hypothesis; a discussion of Aβ oligomeric structures and their stabilizing interactions; a section on molecular dynamics, including its challenges and future directions; and a comprehensive analysis of the inhibitory mechanisms of natural compounds, categorized by their shared structural features. Full article

Background: Current Alzheimer’s disease (AD) treatments primarily focus on symptom management and offer limited potential to arrest disease progression. To address this limitation, we developed baicalin–myricetin (BM) functionalized selenium nanoparticles (SeNPs), termed BMSe@BSA, aimed at multi-targeted neuroprotection. Materials and Methods: BMSe@BSA nanoparticles were synthesized via a gel–sol technique using bovine serum albumin (BSA), ascorbic acid, selenous acid, and BM. Interactions among BSA, BM, and SeNPs were characterized by microscopy and spectrometry. Cytotoxicity was assessed on RAW 264.7 and PC12 cells to determine biocompatibility. Neuroinflammation and cognitive function were evaluated in C57BL6/J mice challenged with Aβ1-42. Recognition memory was tested through open-field exploration, novel object recognition (NOR), and T-maze assays. Inflammatory markers (IL-1β and TNF-α) and microglial changes in the cerebral cortex were quantified, while amyloid fibril morphology was assessed using atomic force microscopy (AFM). Results: Spectroscopic analysis verified successful BM functionalization. Transmission electron microscopy revealed a spherical morphology with an average particle size of 90.57 nm, zeta potential of 27.2 mV, and a polydispersity index (PDI) of 0.270. BM entrapment efficiency reached approximately 90%. Cytotoxicity assays confirmed the nanoparticles’ safety, with no toxicity observed at concentrations up to 400 µg/mL after 4 h of incubation. BMSe@BSA effectively inhibited amyloid fibril formation, downregulated pro-inflammatory cytokine expression, preserved neuronal integrity, and significantly enhanced cognitive performance in AD mouse models. Conclusion: BMSe@BSA appear as a potential nanotherapeutic approach for targeted brain delivery and multi-pathway intervention in Alzheimer’s disease. Full article

Chronic neuroinflammation plays a crucial role in the progression of neurodegenerative diseases (NDs), including Parkinson’s disease (PD) and Alzheimer’s disease (AD). Leucine-Rich Repeat Kinase 2 (LRRK2), a gene linked to familial and sporadic PD, has been positively associated with neuroinflammation in both in vitro and in vivo systems. These observations suggest that LRRK2 might actively contribute to neuronal damage and degeneration in NDs. Based on these premises, we explored the impact of LRRK2-mediated neuroinflammation on neurons in a PD- and AD-related context. We set up a cellular model composed of human induced pluripotent stem cell (hiPSC)-derived neurons (dopaminergic for PD and cholinergic for AD) exposed to inflamed glial medium [α-synuclein pre-formed fibrils (α-syn pffs) for PD and amyloid-β (Aβ)_1–42 fibrils for AD] for several days. To dissect the effect of neuroinflammation, and specifically, the role of LRRK2, on neuronal functions, we first performed transcriptome analysis, and then, we validated the results at functional levels. Interestingly, we found that LRRK2-dependent neuroinflammation contributes to neuronal dysfunctions and death in both ND contexts and that LRRK2 kinase inhibition prevents these detrimental effects. Overall, our results suggest that lowering neuroinflammation through LRRK2 pharmacological inhibition might limit the progression of NDs and thus be neuroprotective. Full article

Acetylcholinesterase (AChE) has emerged not only as a cholinergic enzyme but also as a modulator of β-amyloid (Aβ) aggregation via its peripheral anionic site (PAS), making it a dual-purpose target in Alzheimer’s disease. While classical AChE inhibitors provide symptomatic relief, they lack efficacy against the amyloidogenic cascade. This review highlights recent advances in multifunctional AChE pharmacophores that inhibit enzymatic activity while simultaneously interfering with Aβ aggregation, oxidative stress, metal dyshomeostasis, and neuroinflammation. Particular emphasis is placed on dual-site inhibitors targeting both catalytic and peripheral domains, multi-target-directed ligands (MTDLs) acting on multiple neurodegenerative pathways, and metal-chelating hybrids that address redox-active metal ions promoting Aβ fibrillization. We also discuss enabling technologies such as AI-assisted drug design, high-resolution structural tools, and human induced pluripotent stem cell (iPSC)-derived neuronal models that support physiologically relevant validation. These insights reflect a paradigm shift towards disease-modifying therapies that bridge molecular pharmacology and pathophysiological relevance. Full article

Alzheimer’s disease (AD) is characterized by amyloid-beta (Aβ) plaque accumulation and neurodegeneration. This study identified gyrophoric acid, a lichen-derived phenolic metabolite, as a dual-action Aβ42 inhibitor preventing aggregation and disassembling of mature Aβ42 fibrils. Integrated in silico studies revealed that gyrophoric acid was a strong thermodynamic stabilizer of Aβ42 (MM–GBSA: −27.3 kcal/mol) via entropically driven hydrophobic interactions and disruption of aggregation-prone conformations (100 ns MD simulations). Through biochemical analysis of the fluorescent dye thioflavin T (ThT), gyrophoric acid induced rapid Aβ42 fibril disassembly within 5 h, with time-lapse confocal microscopy quantitatively confirming the near-complete dissolution of large aggregates by 24 h. ADMET profiling revealed favorable pharmacokinetics (moderate oral absorption: 48.5–57.3%; low toxicity) and Lipinski’s rule compliance. These results establish gyrophoric acid as a promising natural bioactive compound for anti-AD therapeutics with a unique hydrophobic-stabilization mechanism. Full article

Aging is associated with aortic stiffening (AoSt), a condition characterized by diminished aortic elasticity that predisposes individuals to cognitive decline, including Alzheimer’s disease (AD). Emerging evidence implicates medin, which is derived from milk fat globule-EGF factor 8 protein (MFG-E8), as a key link between AoSt and AD. Medin aggregates into aortic medial amyloid (AMA), which is found in approximately 97% of Caucasian individuals aged 50 and above, contributing to vascular inflammation, calcification, and loss of arterial elasticity. These changes may promote hyperpulsatile cerebral blood flow and impair glymphatic clearance, resulting in increased deposition of neurotoxic proteins, such as amyloid-β (Aβ) and possibly medin, which colocalizes with vascular Aβ in the brain. Medin enhances Aβ aggregation, generating heterologous fibrils, and thereby contributes to cerebrovascular dysfunction and neuroinflammation. This interaction (cross-seeding) may deteriorate amyloid pathology in both the vasculature and the parenchyma in AD. Furthermore, medin per se causes endothelial dysfunction, increases oxidative stress, and activates glial cells, promoting the development of a pro-inflammatory environment that enhances cognitive decline. In this manuscript, we contend that medin might act as a bridge connecting the age-related increase in aortic stiffness to AD, and therefore, medin might present a novel therapeutic target within this context. This hypothesis deserves experimental and clinical validation. Full article

The present study investigated the neuroprotective potential of the Murraya carbazole derivatives murrayanol, mahanimbine, murrayafoline A, and 9-methyl-9H-carbazole-2-carbaldehyde using in silico and in vitro assays. The pharmacokinetic properties and potential toxicity (ADME/T) of the carbazole derivatives were assessed to evaluate their prospects as up-and-coming drug candidates. Molecular docking was used to investigate the interactions of the compounds with Aβ (PDB: 1IYT, 2BEG, and 8EZE) and AChE receptors (PDB: 4EY7 and 1C2B). The results from the in vitro assays were used to validate and support the findings from the in silico assays. The compounds demonstrated significant inhibition of acetylcholinesterase (AChE), a key target in neurodegenerative disorders. Murrayanol and mahanimbine presented superior inhibitory activity (IC₅₀ ~0.2 μg/mL), outperforming the reference drug, galantamine. The inhibition mechanisms were competitive (murrayanol, murrayafoline A, and 9-methyl-9H-carbazole-2-carbaldehyde) and non-competitive (mahanimbine), supported by low Ki values and strong docking affinities. The compounds also proved effective in reducing Aβ fibrillization (murrayanol: 40.83 ± 0.30%; murrayafoline A: 33.60 ± 0.55%, mahanimbine: 27.68 ± 2.71%). These findings highlight Murraya carbazoles as promising scaffolds for multifunctional agents in AD therapy. Further optimization and mechanistic studies are warranted to advance their development into clinically relevant neuroprotective agents. Full article