Search Results (910)

Interleukin-10 (IL-10) is a key immunoregulatory cytokine that suppresses inflammatory gene transcription in myeloid cells through signal transducer and activator of transcription 3 (STAT3). In Alzheimer’s disease and neuroinflammation, microglia express IL10ra and exhibit STAT3 Tyr705 phosphorylation following IL-10 stimulation, indicating IL-10 receptor-dependent STAT3 activation. Recent studies demonstrate that IL-10 induces promoter-selective STAT3-dependent transcriptional regulation in microglia through chromatin-associated mechanisms, whereas gp130-dependent cytokines activate STAT3 to induce transcription of defined target genes, including Socs3 and Ccl5. Following IL-10 receptor activation, STAT3 binds regulatory regions of inflammatory genes, including Il1b, Tnf, Il6, and Nlrp3, with reduced RNA polymerase II and NF-κB binding. IL-10-dependent transcriptional repression involves formation of a nuclear SHIP1–STAT3 complex, localization of histone deacetylase (HDAC)1 and HDAC2 to H3K4me1-enriched enhancer regions, reduced H3K27ac, and decreased chromatin accessibility at regulatory regions of inflammatory genes. IL-10-activated STAT3 induces Socs3, which regulates JAK1 and TYK2 activity and STAT3 phosphorylation. Impairment of IL-10 receptor signaling in microglia is associated with increased inflammatory gene expression, enhanced inflammasome-related transcription, demyelination, and amyloid accumulation. This review focuses on IL-10–STAT3-dependent transcriptional regulation in microglia, including receptor signaling, chromatin-associated mechanisms, and disease-associated gene expression in Alzheimer’s disease and neuroinflammation. Full article

Functional amyloids are widely distributed in bacteria and play important roles in biofilm formation and microbial physiology. However, most currently known bacterial amyloids have been identified through sequence homology to a limited number of prototype proteins, such as the curli subunit CsgA of Escherichia coli. This approach may overlook amyloidogenic sequences that lack recognizable similarity to these canonical systems. In this study, a cross-species, motif-based computational strategy was used to explore whether conserved sequence features derived from mammalian serum amyloid A (SAA) proteins could provide clues for identifying potential amyloidogenic motifs in bacterial proteomes. Comparative analysis of mammalian SAA isoforms identified a conserved sequence segment with predicted aggregation propensity, within which the hydrophobic motif SIAIILCILIL was observed in murine SAA3. Database searches revealed that similar sequence motifs occur in several proteins encoded by Gram-positive bacteria, including multiple proteins in Clostridioides difficile. To further explore whether C. difficile produces extracellular structures capable of interacting with amyloid-binding dyes, Congo Red-supplemented agar assays were performed. After 48 h of growth, both clinical isolates and a laboratory reference strain exhibited Congo Red-binding colony phenotypes. Because Congo Red binding can arise from several extracellular components and cannot be attributed to a specific protein or sequence motif, these observations should be interpreted cautiously. Taken together, this study presents a motif-based computational framework for identifying candidate amyloidogenic motifs across species and highlights sequence features in bacterial proteomes that may warrant further biochemical and structural investigation. The results should be regarded as hypothesis-generating and provide a basis for future experimental validation of potential amyloid-forming proteins in bacteria. Full article

Background: Alzheimer’s disease (AD) remains an incurable disorder with severe clinical consequences. The type 3 diabetes hypothesis posits that AD may constitute a neuroendocrine disorder driven by disrupted insulin and insulin-like growth factor signaling. Amyloid pathogenesis in AD is characterized by the accumulation of beta-amyloid (Aβ) monomers, their subsequent oligomerization, and amyloid deposition. One of the causes of Aβ accumulation is disruption of amyloid precursor protein (APP) processing due to imbalance in ADAM10 and BACE1 expression. In recent years, increasing attention has been devoted to investigating the role of environmental factors in AD pathogenesis. The receptor for advanced glycation end products (RAGE) serves as a key molecular link between environmental exposure and neuroinflammatory pathology. Formaldehyde (FA) is one of the most widespread environmental pollutants. Its involvement in amyloid plaque formation has been previously reported; however, the molecular mechanisms underlying this process remain insufficiently understood. Moreover, most available data are based on prolonged FA exposure, whereas industrial FA emissions are often short-term. The objective of this study was to determine whether brief intranasal administration of FA, modeling episodic industrial pollution, induces RAGE-mediated neuroinflammation and amyloid deposition in CD1 mice. Methods: Mice received intranasal FA at environmentally relevant 0.02 mg/day or 0.2 mg/day doses for seven days; an additional group was co-treated with insulin. Cognitive function was assessed using passive avoidance (PA) and radial arm maze (RAM) tests, and synaptic plasticity was evaluated by electrophysiology. Hippocampal tissue was analyzed for RAGE expression, ADAM10/BACE1 gene balance, Aβ42 monomer levels, and amyloid deposits using optimized Thioflavin-S (Th-S) staining. Results: We observed cognitive decline in mice receiving intranasal FA administration. Elevated blood glucose levels were also observed following intranasal FA exposure. Sustained impairment of glucose metabolism led to overexpression of the RAGE in the hippocampus. There was also an imbalance of ADAM10 and BACE1 expression in the hippocampus. This was caused by overexpression of RAGE, as the enhanced interaction of the ligand and RAGE is a key factor disrupting this balance. Finally, Th-S staining confirmed amyloid deposition in mice subjected to intranasal FA exposure. Conclusions: This study provides new insights into the RAGE-mediated mechanisms by which FA contributes to the pathogenesis of 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

The islet amyloid polypeptide (IAPP) is a peptide hormone playing key biological roles, including glucose homeostasis and regulation of food intake, conferring high therapeutic potential to treat metabolic disorders. Nonetheless, IAPP is mainly known as the major component of the amyloid fibrils observed in the pancreatic islets of patients afflicted with type 2 diabetes, and the accumulation of these insoluble protein deposits correlates closely with the loss of pancreatic β-cells. The inherent aggregation propensity of this peptide hormone is not only associated with the pathogenesis of type 2 diabetes but also complicates the design of IAPP derivatives for the treatment of metabolic disorders. Accordingly, elucidating the molecular mechanisms by which IAPP self-assembles into amyloid fibrils is critical to identify chemical strategies to arrest aggregation, as well as to design safe and stable IAPP-derived therapeutics. This review aims at presenting the different mechanistic models of IAPP aggregation and how to exploit this information to identify inhibitors of amyloid formation and non-aggregating peptide agonists. After discussing the conformational conversions allowing IAPP to undergo a mainly disordered monomeric conformation into ordered cross-β-sheet quaternary supramolecular structures, we present chemical strategies to prevent amyloid deposition and to develop non-aggregating peptide-based therapeutics. 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

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

Copper and zinc nanoparticles have been suggested as potent anticancer agents, particularly against osteosarcoma, a highly aggressive bone cancer with limited treatment options. In order to avoid systemic toxicity, biomolecular carriers able to chelate metal ions and deliver them in a targeted manner to the vicinity of cancer cells need to be developed. Herein, we have used a histidine-containing, cyclic dipeptide as a carrier able to chelate stabilized copper and zinc nanoparticles. The cyclic peptide cyclo-(histidine-phenylalanine) (cHF) self-assembled into amyloid-type fibrils; morphological and structural characterization following metal addition confirmed the formation of cHF−CuNPs and cHF–ZnNPs. These composite nanoparticles demonstrated bacteriostatic activity against Escherichia coli and Staphylococcus aureus at the in vitro level. We evaluated the optimal concentration of cHF–metalNP complexes with limited cytotoxicity to L929 fibroblasts and high cytotoxic effects against MG-63 osteosarcoma cells. Their cytotoxicity was particularly pronounced at pH 6.4, which emulates the tumor microenvironment. The cHF peptide alone did not demonstrate significant antimicrobial or cytotoxic effects to both cell types, suggesting that it can act as a cytocompatible, pH-responsive carrier of metal ions with targeted dual functionality against both microbial infections and osteosarcoma cancer cells. 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

Background: Neurodegeneration and dementia are key factors in Alzheimer’s disease (AD). The deposition of amyloid-ß into senile plaques in the brain parenchyma and in cerebral vessels known as cerebral amyloid angiopathy (CAA) are the main clinical parameters of AD. Acute myocardial infarction (AMI) and AD share a comparable pathophysiology. However, the underlying mechanisms and the consequences of AMI in AD patients are unclear to date. Methods: AD transgenic APP23 mice were analyzed in experimental AMI using the closed-chest model. Results: APP23 mice displayed significantly decreased left ventricular function as detected by FS/MPI (fractional shortening/myocardial performance index) after 24 h and 3 weeks after ligation of the LAD compared to WT controls. No differences have been observed in infarct and scar size. The analysis of cardiac remodeling after 3 weeks showed an altered composition of the collagen tissue of the scar with elevated tight but reduced fine collagen in APP23 mice. Altered scar formation was accompanied by elevated degranulation of platelets following activation of the collagen receptor GPVI. Conclusions: These results suggest that AD patients are at higher risk for cardiac damage after AMI. This implies the need for a personalized therapy of AMI in AD patients. Full article

In both Alzheimer’s disease (AD) patients and animal models, senile plaques are generally observed in the cerebral cortex rather than the cerebellum. The mechanisms underlying the regional resistance of the cerebellum to amyloid plaque deposition remain poorly understood. We investigated this cerebellar resistance using 5xFAD mice, an amyloidosis model with high expression of mutant human APP and PSEN1 in the cortex and cerebellum. In aged 5xFAD mice, the cerebellum had minimal amyloid-β (Aβ) deposition despite robust transgene expression, correlating with lower expression levels of IBA1, CD68, TREM2, and CD36 (although elevated expression of CD45 and MHC I) compared to the cortex. Consistent with the absence of plaques, cerebellar tissue lacked the dystrophic VGLUT1-positive synaptic accumulations prominent in the cortex. Cerebellar microglia maintained a distinct, less inflammatory phenotype yet displayed efficient clearance activity. Notably, ASC inflammasome specks—capable of seeding Aβ aggregation—were paradoxically more abundant in the cerebellum, implying that rapid Aβ clearance prevents these seeds from driving plaque formation. Furthermore, key extracellular matrix (ECM) proteoglycans brevican and aggrecan were elevated in the 5xFAD cerebellum. Cerebellar microglia showed enhanced internalization of brevican alongside small Aβ aggregates, exceeding that in cortical microglia. These findings indicate that region-specific microglial and ECM interactions—particularly efficient uptake and degradation of ECM–Aβ co-aggregates—may underlie the cerebellum’s resilience to amyloid plaque 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

Background/Objectives: Alzheimer’s disease (AD) is a neurodegenerative disorder in which altered microvascular circulation participates in the pathogenesis. The lack of therapeutic treatments for AD makes the development of strategies aimed at preventing or delaying the disease onset urgent. In recent years, several studies have highlighted that a diet rich in antioxidants and anti-inflammatory compounds may positively impact AD development. In this study, we assessed the impact of a diet enriched with Acebuche (ACE) oil, an extra-virgin olive oil particularly rich in antioxidants and anti-inflammatory compounds, on AD progression in the 5xFAD mouse model. Methods: After weaning, wild-type (WT) and 5xFAD mice received the standard or the ACE oil-enriched diet. At 2, 4 and 6 months, the effects of the diet were evaluated on AD-related microvascular aberrancies, beta-amyloid (Aβ) formation, hypoxic state, blood–brain barrier (BBB) alterations, neuroinflammation and cognitive impairment. Metabolic parameters were also evaluated. Results: In 5xFAD mice, the ACE oil-enriched diet prevented alterations in cerebral microcirculation. Moreover, Aβ accumulation, downregulation of Aβ-degrading enzymes, hypoxia, BBB breakdown, neuroinflammation, and cognitive deficits were delayed by the ACE oil-enriched diet. However, some of these effects were reduced at 6 months, in concomitance with systemic metabolic changes, such as hepatic steatosis, evidenced in both WT and 5xFAD mice receiving the ACE oil-enriched diet. Conclusions: Overall, the present results represent proof of concept for the validity of early dietary interventions in AD prevention. Full article