Search Results (266)

Alzheimer’s disease (AD) is one of the most prevalent neurodegenerative disorders worldwide and is characterized by progressive memory impairment, cognitive decline, and behavioral dysfunction. The brain’s high energy demand makes it vulnerable to hypoxia, which can trigger AD pathology. Hypoxia-inducible factor (HIF) is a transcription factor that mediates cellular and tissue adaptation to low oxygen levels. HIF-1 plays a dual role in AD: on the one hand, it is considered a potential neuroprotective target; on the other hand, its activation may exacerbate disease pathogenesis by promoting amyloid plaque formation. Given this ambiguity, further studies are needed. This study investigated the HIF prolyl hydroxylase inhibitor Roxadustat in 6-month-old male 5xFAD mice. Stabilization of the HIF-1 complex exerted a positive effect on learning ability and the retention of long-term spatial memory in 6-month-old male 5xFAD mice. Four-week treatment with Roxadustat significantly reduced pathological morphological alterations in cells of the prefrontal cortex. In addition, animals treated with Roxadustat exhibited significantly increased expression of the brain-derived neurotrophic factor (BDNF) in the cerebral cortex. Our findings suggest that stabilization of the HIF-1 complex through inhibition of HIF prolyl hydroxylase may represent a promising strategy for neuroprotection in AD. Full article

Alzheimer’s disease (AD) involves oxidative stress, metal dyshomeostasis, and toxic oligomers of the amyloid-β peptide (Aβ_1-42), calling for multifunctional agents. We investigated a panel of imidazo[1,2-a]pyridines bearing catechol or resorcinol motifs previously designed as SIRT1-activating agents. Their antioxidant profile was evaluated using in vitro DPPH and ABTS assays, which revealed promising radical scavenging activities, and TBARS assays on rat brain homogenates showing inhibition of lipid peroxidation, strictly dependent on the phenolic pattern. UV–Vis studies revealed metal-binding properties, particularly Cu²⁺ and Fe²⁺ interactions. In Aβ_1-42 aggregation assays, the most active derivatives appeared to promote fibril maturation and the growth of large, ThT-low aggregates with distinct morphological features observed by TEM. Notably, Aβ_1-42 aggregates generated in the presence of these compounds exhibited reduced cytotoxicity, preserved cell viability, and induced lower ROS levels in RA-differentiated SH-SY5Y cells compared to aggregates formed in their absence. Imaging and FRET analyses further indicated reduced formation of membrane-binding toxic species. Overall, our data suggest that polyphenolic imidazo[1,2-a]pyridines can remodel Aβ_1-42 aggregation, redirecting it toward structurally distinct and less toxic assemblies, while also counteracting oxidative and metal-associated damage. These findings highlight their potential as multifunctional agents capable of addressing several pathological hallmarks of AD. Full article

Background/Objectives: Protein misfolding and amyloid fibril formation underlie several degenerative diseases, including Alzheimer’s disease and Parkinson’s disease. Alpha-1 antitrypsin (A1AT), a serpin protein, is particularly prone to misfolding, with polymerization and aggregation implicated in alpha-1 antitrypsin deficiency and associated hepatic and pulmonary disorders. In this study, we examined the structural changes in A1AT induced by the fluorinated alcohol, trifluoroethanol (TFE), and assessed the inhibitory effects of two natural polyphenols, amentoflavone (AMF) and theaflavin (TF), on aggregation and fibril formation. Methods: A library of selected phytocompounds was virtually screened against the crystal structure of A1AT (PDB 3NE4) using AutoDock Vina to elucidate their binding affinity towards it. Based on binding affinities, two compounds, AMF and TF, were selected for further studies. Protein aggregation was induced with TFE, and the protective effects of AMF and TF were evaluated using protease inhibitory activity, intrinsic fluorescence, turbidity, Rayleigh scattering, ANS fluorescence, and ThT fluorescence assays. Furthermore, 100 ns molecular dynamics simulation and MM-PBSA calculations were performed to assess the stability and binding interactions of the A1AT–ligand complexes. Results: Pre-treatment of A1AT with AMF or TF significantly inhibited TFE-induced aggregation in a dose-dependent manner, with AMF being consistently more effective. ThT fluorescence analysis revealed a ~60–65% decrease in aggregate formation upon treatment with polyphenols, with IC₅₀ values estimated at ~40 µM for AMF and ~50 µM for TF, both of which are statistically significant. Molecular docking and 100 ns molecular dynamics simulation also revealed stable A1AT–polyphenol interactions, with AMF exhibiting greater binding affinity and greater attenuation of solvent-induced conformational perturbation. Conclusions: Collectively, our findings show that TFE causes A1AT misfolding via a molten globule-like intermediate, resulting in fibril formation at 30–40% TFE, and natural polyphenols AMF and TF inhibited aggregation in a concentration-dependent manner. These observations suggest the potential of AMF and TF as lead scaffolds for anti-aggregation strategies, as modulators of amyloidogenic processes. Full article

Background/Objectives: Beta amyloid (Aβ) aggregates play a central role in the pathophysiology of Alzheimer’s disease (AD), and their detection and modulation remain major challenges in developing effective therapeutic and diagnostic strategies. Previously, gold nanoparticles with plasmonic and optical properties in the near-infrared (NIR) region and photothermal capabilities have been designed for detecting and disaggregating Aβ aggregates. However, these systems often face limitations related to biodegradability, long-term accumulation, and safety. In this work, a degradable NIR-responsive nanosystem based on small gold nanoparticles (sAuNPs), potentially excretable due to their small size, encapsulated within bovine serum albumin (BSA) and functionalized with the all-D peptide D3, was developed to inhibit Aβ aggregation. Methods: sAuNPs (~5–6 nm), functionalized with HS-PEG-NH₂, were encapsulated into BSA nanoparticles using a desolvation method and subsequently conjugated to D3, resulting in the nanosystem f-sAuNPs-BSANPs-D3. The nanosystem was characterized by UV–Vis–NIR spectroscopy, dynamic light scattering, zeta potential analysis, electron microscopy, and nanoparticle tracking analysis. The effects of the nanosystem on Aβ_1–42 aggregation were evaluated using a thioflavin T assay and electron microscopy. Additionally, the effects of f-sAuNPs-BSANPs-D3 on cell viability and its stability against trypsin digestion were assessed. Results: The nanosystem exhibited a measurable photothermal response under NIR irradiation and significantly reduced fibril formation. It did not affect the viability of SH-SY5Y neuronal cells at the tested concentrations. Trypsin incubation experiments demonstrated that the nanosystem remained stable at low enzyme concentrations mimicking plasma conditions, whereas higher enzyme concentrations induced degradation of the albumin matrix and subsequent disaggregation of sAuNPs. Conclusions: Overall, this study presents a degradable, albumin-based sAuNP nanosystem with NIR-responsive properties and potential for nanomedicine applications to inhibit Aβ aggregation in AD. 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

Amyloid-β peptides (Aβ) are considered a main culprit of Alzheimer’s disease (AD), leading to synaptic dysfunction and memory deficits. Although studies in animal models of AD converge to show alterations of synaptic plasticity, namely of long-term potentiation (LTP), the mechanisms through which Aβ affects synaptic function remain to be unveiled. In this study, we established experimental conditions showing that the acute exposure of mouse hippocampal slices to optimized concentrations of Aβ impaired short-term (PPF-paired-pulse facilitation) and long-term (LTP-long-term potentiation) plasticity without altering basal synaptic transmission. We observed that the elimination of extracellular adenosine with adenosine deaminase abrogated the impact of Aβ on synaptic plasticity, showing a mandatory involvement of extracellular adenosine in the neurophysiological effects of Aβ. Additionally, inhibiting adenosine receptor function with caffeine, as well as selectively blocking adenosine A₁ receptors (A₁R) with DPCPX, or adenosine A_2A receptor (A_2AR) with either an antagonist SCH58261 or through knocking out A_2AR, demonstrated that acute Aβ modified mouse hippocampal PPF via A₁R and LTP through A_2AR. Furthermore, the use of slices from mice bearing forebrain-neuron A_2AR deletion, along with the application of α,β-methylene ADP, a CD73 inhibitor, confirmed that the neurophysiological actions of Aβ on hippocampal LTP occur selectively through the overfunction of neuronal A_2AR via CD73-mediated formation of extracellular adenosine. Overall, the exploitation of a neurophysiological model of early AD, based on the acute administration of Aβ to hippocampal slices, confirmed the critical involvement of adenosine signaling in the impact of Aβ on synaptic plasticity. Full article

Tau protein, a microtubule-associated protein widely distributed in the central nervous system, aggregates abnormally and forms neurofibrillary tangles in neurodegenerative diseases. Particularly in Alzheimer’s disease, pathological tau protein aggregates disrupt the structure and function of neurons, triggering other neurodegenerative-related processes such as neuroinflammation and amyloid plaque formation, and finally leading to neuronal death. Several classes of drugs targeting neurofibrillary tangles have recently been studied, with tau protein aggregation inhibitors as a key research direction. In the context of emerging therapeutic perspectives, this review aims to provide an updated, practical overview of currently available tau protein aggregation inhibitors and future research directions. The first part of the manuscript highlights the pathophysiological basics of tau protein aggregation and tau-related changes in neurodegenerative disorders, with a focus on Alzheimer’s disease pathology. Subsequently, the most relevant classes of drugs that inhibit tau protein aggregation, including small-molecule inhibitors and natural compounds, are presented, with examples from recent clinical trials. Finally, beyond summarizing established classes of tau aggregation inhibitors, this review places particular emphasis on emerging and comparatively underexplored compounds with dual activity against both tau and amyloid-β pathology. The originality and novelty of this work arise from the systematical analysis of recent preclinical and clinical evidence with a translational, practice-oriented perspective, highlighting mechanistic convergence, repurposing opportunities, and therapeutic combinations that may better reflect the multifactorial nature of neurodegenerative diseases. Thus, this work provides a forward-looking framework for future drug development and identifies promising candidates that may shape the next generation of disease-modifying therapies. Full article

Cold-inducible RNA-binding protein (CIRP) is a critical molecule in the central nervous system (CNS) with functions that depend on its subcellular localization, exhibiting biphasic regulatory roles in both physiological and pathological processes. Under physiological conditions, intracellular cold-inducible RNA-binding protein (iCIRP) contributes to the maintenance of circadian rhythms by regulating the stability of core clock gene mRNAs and exerts neuroprotective effects during mild hypothermia by preserving the blood–brain barrier and inhibiting apoptosis. Pathologically, extracellular cold-inducible RNA-binding protein (eCIRP) functions as a damage-associated molecular pattern (DAMP) that drives neuroinflammation and brain injury. In ischemic stroke (IS), eCIRP promotes neutrophil extracellular trap (NET) formation and increases microglial activity via the Toll-like receptor 4 (TLR4) pathway. In cerebral ischemia–reperfusion (I/R) injury, eCIRP activates oxidative stress and the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome through the TLR4 axis, exacerbating mitochondrial damage. In intracerebral hemorrhage (ICH), eCIRP further amplifies inflammation via the interleukin-6 receptor (IL-6R)/signal transducer and activator of transcription 3 (STAT3) signaling pathway. In traumatic brain injury (TBI), eCIRP activates the endoplasmic reticulum stress pathway, intensifying apoptosis. In Alzheimer’s disease (AD), eCIRP regulates tau phosphorylation and β-amyloid (Aβ) metabolism and may mediate the link between alcohol exposure and AD pathology. Preclinical studies indicate that serum eCIRP levels correlate with IS and ICH severity, highlighting its potential as a biomarker. This systematic review elucidates the mechanisms of CIRP in CNS diseases, providing insights for understanding and preventing conditions such as IS, cerebral I/R injury, ICH, TBI, and AD. Full article

Environmental lead (Pb) exposure remains a significant public health concern, and its association with cerebrovascular injury and Alzheimer’s disease (AD) is increasingly recognized. In this study, we demonstrated using an in vitro system that Pb exposure significantly increased the expression and release of endothelial plasminogen activator inhibitor-1 (PAI-1). A conditioned medium collected from Pb-treated endothelial cells induced the formation of complement component 3 (C3)⁺ decorin⁺ A1-like astrocytes, which had been shown to be specifically associated with vascular amyloid. Immunoprecipitation with the PAI-1 antibody to remove PAI-1 from the culture medium, or treatment of endothelial cells with PAI-1 inhibitors, significantly inhibited the formation of C3⁺ decorin⁺ A1-like astrocytes. Furthermore, in vivo studies further supported this finding, indicating that lead does indeed increase the number of perivascular C3⁺ decorin⁺ A1-like astrocytes, and that the PAI-1 inhibitor blocked this induction. Building upon our previous findings, we demonstrate that lead exposure may induce cerebral amyloid angiopathy (CAA) pathology through the formation of C3⁺ decorin⁺ A1-like astrocytes mediated by endothelial cell PAI-1. Our results strongly suggest that PAI-1 is a key mediator linking endothelial stress and lead-induced vascular amyloidosis pathology. Full article

Olive pomace (OP), a by-product of olive oil production, is a sustainable resource rich in bioactive compounds with potential applications in cosmetics and pharmaceuticals. This study investigates the protective effects of olive pomace juice (OPJ) against H₂O₂-induced neuronal damage and LPS-induced inflammatory responses in HT22 and BV2 cells, respectively. OPJ suppressed H₂O₂-induced cell death and exerted anti-apoptotic effects by reducing the BAX/BCL2 ratio and caspase-3 cleavage. OPJ also mitigated neurodegenerative hallmarks by decreasing amyloid fibrils formation and inhibiting β-secretase and acetylcholinesterase (AChE) activity. Mechanistically, OPJ enhanced antioxidant response by upregulating Nrf2 and its downstream molecule HO-1, along with increasing mRNA levels of antioxidant enzymes, including catalase, SOD1, and GPx. OPJ further activated AMPKα–SIRT1–PGC1α signaling and CREB–BDNF–TrkB signaling, suggesting modulation of key antioxidant, anti-apoptotic, and neurotrophic pathways. In BV2 cells, OPJ downregulated pro-inflammatory cytokines (IL-6 and IL-1β) and decreased iNOS and COX-2 expression through suppression of NF-κB and MAPK signaling pathways. HPLC analysis identified hydroxytyrosol (10.92%) as the major active compound in OPJ, which compared with tyrosol (2.18%), and hydroxytyrosol exhibited greater neuroprotective and anti-inflammatory effects than tyrosol. This study highlights the potential of OPJ and its major compound, hydroxytyrosol, as functional agents for mitigating neurodegeneration-related cellular response, supporting its application in the food and pharmaceutical industries. Full article

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 is characterized by the accumulation of neurotoxic forms of amyloid-beta (Aβ) in the brain, leading to synaptic dysfunction, neuroinflammation, and neuronal death. The tetrapeptide HAEE crosses the blood–brain barrier (BBB), inhibits the formation of toxic Aβ oligomers, and reduces amyloid burden in vivo. However, the mechanisms of HAEE’s anti-amyloidogenic effect remained incompletely understood. In this study, we investigated the mechanism of HAEE-dependent Aβ clearance both in vitro and in vivo. Using ELISA, we assessed the HAEE effect on the levels of Aβ, IL-6, and TNFα in mouse brain tissue following intracerebroventricular administration. The mechanism of the anti-Aβ effect of HAEE was studied using primary brain cell cultures and a BBB transwell model through ELISA, flow cytometry, and microscopy. We showed that HAEE reduced Aβ level by 35% and IL-6 level by 40% in mouse brain tissue. HAEE enhanced Aβ clearance via LRP1- and PgP-dependent Aβ transport through the BBB and doubled the rate of Aβ degradation by microglia. In addition to inhibition of Aβ aggregation, HAEE dissolved already formed Aβ oligomers. The HAEE-induced decrease in IL-6 levels in the mouse brain was associated with reduced pro-inflammatory activation of microglia. Thus, HAEE’s effect against Aβ-related neuropathologies is realized through a decrease in the level of toxic Aβ oligomer and inhibition of neuroinflammation. Full article

Diabetic nephropathy (DN) remains the leading cause of end-stage renal disease (ESRD) worldwide, primarily affecting individuals with Type 2 Diabetes Mellitus (T2DM). While traditional risk factors—such as hypertension, poor glycemic control, and dyslipidemia—are well known, recent research has illuminated the pivotal role of inflammation in DN pathogenesis. Inflammatory processes involving chemokines, cytokines, immune cell infiltration, and pro-fibrotic signaling pathways (e.g., NFκB, JAK/STAT) contribute significantly to glomerular and tubulointerstitial damage. Key immune players include macrophages and T lymphocytes, particularly CD4⁺ T cells, which correlate with disease severity and progression. Serum Amyloid A (SAA), an acute-phase reactant traditionally associated with Serum Amyloid A Amyloidosis (AA amyloidosis), has emerged as both a biomarker and active mediator of renal inflammation in DN. SAA promotes cytokine release, leukocyte recruitment, and extracellular matrix remodeling, contributing to glomerular and tubular injury. Elevated Saa3 expression in experimental models correlates with DN progression, while activation of the advanced glycation end products and the receptors for advanced glycation end products (AGE–RAGE) axis in podocytes enhances SAA upregulation and inflammatory signaling. Increasing evidence now indicates that SAA functions, not only as a marker of systemic inflammation, but also as a mechanistically significant driver of intrarenal injury, bridging metabolic dysregulation with sustained inflammatory and fibrotic signaling. Emerging therapeutic approaches—including interleukin 6 (IL-6) blockade, inhibition of AGE formation, targeted anti-fibrotic agents, and recently developed SAA-directed RNA or peptide therapeutics—underscore the therapeutic potential of modulating SAA activity in DN. Preclinical evidence further supports the efficacy of monoclonal antibodies, signaling inhibitors, and dietary anti-inflammatory compounds in mitigating renal injury. Collectively, these developments position SAA as a central mediator at the intersection of metabolic, inflammatory, and fibrotic pathways, highlighting its promise as both a diagnostic biomarker and a therapeutic target for early intervention in diabetic kidney disease. 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 (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