Search Results (2,506)

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

Mitochondrial dysfunction is a relevant hallmark of Alzheimer’s disease (AD), contributing to the impaired metabolic homeostasis involved in neuronal loss and cognitive decline. In this study, we target the metabolic dysfunction occurring in AD through a novel pharmacological approach involving the modulation of glutamate dehydrogenase (GDH), which converts glutamate to α-ketoglutarate and supports the tricarboxylic acid (TCA) cycle. In our experimental models (i.e., differentiated SH-SY5Y cells and primary rat cortical neurons exposed to glyceraldehyde and amyloid-beta peptide 1-42, respectively), the allosteric GDH activator 2-Aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH) increased mitochondrial ATP production, improved cellular bioenergetics, and reduced oxidative stress, ultimately promoting neuronal survival. Ionic dysfunctions in AD are linked to disrupted calcium homeostasis and organelle storing properties. In this context, GDH activation potentiated mitochondrial and endoplasmic reticulum calcium buffering capacity by enhancing store-operated calcium entry. Oxidative stress, largely driven by mitochondrial ROS overproduction, represents another major contributor to AD pathology. In our AD models BCH-mediated GDH activation reduced ROS formation and restored mitochondrial membrane potential (ΔΨ_m). Importantly, these metabolic and ionic improvements were associated with decreased accumulation of amyloid-β (Aβ_1-42) and phosphorylated tau (pTau), two key AD biomarkers. Overall, modulation of the GDH/TCA pathway represents a promising approach for restoring metabolic dysfunctions and counteracting oxidative stress and ionic dysregulation and therefore AD neurodegeneration. Full article

Background: Amyloid-related pathways are well studied in neurodegenerative diseases but remain poorly characterized in gliomas. Amyloid-related transcriptional programs in low-grade gliomas (astrocytoma grade II-III) and oligodendrogliomas, and their association with patient survival, were analyzed in this study. Methods: Transcriptomic data from 193 grade II-III astrocytomas and 191 oligodendrogliomas were analyzed to evaluate histology-specific expression patterns and prognostic significance. Differential and single-sample gene set enrichment analyses (ssGSEA) were used to calculate per-sample enrichment scores for 30 amyloid-related Gene Ontology biological process gene sets across the combined cohort. These scores were used to compare pathway activity between grade II-III astrocytoma and oligodendroglioma samples. Pathway-level survival analyses were performed for each tumor type using ssGSEA enrichment scores to evaluate associations with overall survival. Results: Distinct amyloid-related transcriptional programs were identified between glioma subtypes. Grade II-III astrocytomas showed enrichment of pathways related to amyloid precursor protein (APP) processing and amyloid-β clearance, whereas oligodendrogliomas were enriched in lipid transport and negative regulation of amyloid formation. Survival analyses revealed that higher activity of the positive regulation of APP biosynthetic process and amyloid-β clearance by transcytosis was significantly associated with worse overall survival in grade II-III astrocytoma, but not in oligodendroglioma. Gene-level analyses in astrocytoma demonstrated consistent survival associations across multiple genes within these pathways, supporting coordinated pathway-level effects rather than isolated single-gene prognostic markers. Conclusions: Amyloid-related transcriptional programs differ substantially between diffuse glioma subtypes. Increased APP biosynthesis and amyloid-β transcytosis pathways are associated with poorer survival specifically in grade II-III astrocytoma, suggesting a potential role for amyloid metabolism in tumor progression. These findings identify APP-related pathways as candidates for further mechanistic investigation and potential therapeutic targeting in grade II-III astrocytoma. Full article

Background: Vascular dysfunction and neurovascular inflammation are increasingly recognized as contributors to Alzheimer’s disease (AD) pathophysiology, particularly through interactions with tau-related neurodegeneration. Endothelial adhesion molecules, including vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1), play key roles in blood–brain barrier regulation and immune-vascular crosstalk, yet their relevance to long-term disease progression and established AD biomarkers remains incompletely understood. Methods: Using data from the Alzheimer’s Disease Neuroimaging Initiative (ADNI), we examined associations between baseline cerebrospinal fluid (CSF) levels of VCAM-1 and ICAM-1 and clinical progression, CSF biomarkers, neuroimaging measures, and cognitive outcomes over up to 10 years of follow-up. This study included 294 participants (87 cognitively normal, 129 with mild cognitive impairment, and 78 with AD). Multivariable logistic regression was used to assess associations with diagnostic progression, and linear regression models examined relationships with baseline and longitudinal measures of tau, amyloid-β, hippocampal volume, Fluorodeoxyglucose-Positron Emission Tomography (FDG-PET) metabolism, and cognition. Models were adjusted for age, sex, apolipoprotein E epsilon 4 (APOE ε4) status, baseline diagnosis, and baseline CSF amyloid-β, with false discovery rate correction applied for multiple comparisons. Results: Baseline CSF VCAM-1 and ICAM-1 levels did not differ across diagnostic groups. However, higher baseline levels of both markers were nominally associated with increased odds of disease progression. Notably, ICAM-1 showed a strong and robust association with baseline CSF phosphorylated tau, which remained significant after multiple-comparison correction. VCAM-1 was also associated with tau pathology, though this did not survive correction. Neither marker was associated with baseline or longitudinal changes in hippocampal volume, FDG-PET metabolism, or cognitive performance. Conclusion: CSF VCAM-1 and ICAM-1 appear to reflect neurovascular inflammatory processes linked to tau pathology rather than markers of clinical stage or longitudinal neurodegeneration. These findings support a role for endothelial activation in AD pathophysiology and highlight vascular–immune mechanisms as potential contributors to tau-related disease vulnerability. Full article

Amyloid-β (Aβ) protein, a cleavage product of the amyloid precursor protein (APP), is the main component of neuritic plaques in Alzheimer’s disease (AD), and its accumulation has been considered as the molecular driver of Alzheimer’s pathogenesis. Aβ has been a primary target for therapy since the amyloid cascade theory was put forth, with methods designed to prevent the generation of Aβ. The APP 5′-untranslated region (UTR) mRNA encodes a functional structured iron-responsive element (IRE) that represents a potential target for small molecule inhibitors as an anti-amyloid therapy for AD. Here, we offer a comprehensive strategy that uses RNA-targeted binding to inhibit APP translation. The IRE family is among the few 3-D mRNA regulatory elements with a known 3-D structure. Accordingly, we exploit these structural and functional characteristics as our strategy to target APP IRE structured mRNA to identify anti-amyloid drugs. The mRNA encoding proteins involved in iron metabolism are regulated by this family of similar nucleotide sequences. Post-transcriptional control of cytoplasmic mRNA is a rapidly developing area of biomedicine. Across animals, evolutionarily conserved IRE mRNAs serve as a model system for 3-D mRNAs. IRE mRNAs have shown great promise for chemical manipulation of mRNA and protein expression in biological systems by yielding “proof of principle” data for small molecules targeting mRNA structures. A novel approach to identifying RNA-directed therapeutics to regulate APP expression and Aβ-peptide generation for AD treatments is exemplified by APP 5′-UTR-directed small molecule inhibitors. Full article

Extracellular vesicles (EVs) are nanoscale membrane-bound particles that mediate intercellular communication by transferring proteins, nucleic acids, lipids, and metabolites. Increasing evidence implicates EVs in Alzheimer’s disease (AD) pathogenesis through the propagation of amyloid-β, tau, and neuroinflammatory signals across neural and glial networks. In parallel, EVs isolated from biofluids have emerged as promising sources of disease-associated biomarkers and potential therapeutic carriers. This review aims to synthesize current evidence on EV-mediated mechanisms in AD, evaluate the diagnostic value of EV-associated biomarkers, and discuss emerging EV-based and bioengineered therapeutic strategies. We summarize how EVs derived from neurons, astrocytes, microglia, and peripheral cells contribute to amyloid-β and tau spread, neuroinflammation, synaptic dysfunction, and metabolic stress in AD. Disease-associated alterations in EV cargo from blood, cerebrospinal fluid, and urine are critically assessed for biomarker applications. We further highlight advances in EV bioengineering, including cargo loading, surface modification, targeting strategies, and modulation of EV biogenesis. Finally, key translational challenges—such as EV heterogeneity, biodistribution, immune clearance, and standardization—are discussed to define future directions for leveraging EVs as diagnostic and therapeutic platforms in AD. Full article

Alzheimer’s disease (AD) and mild cognitive impairment (MCI) are major causes of cognitive decline. Antidiabetic medications such as metformin, pioglitazone, and GLP-1 receptor agonists have been proposed as potential neuroprotective therapies. We assessed whether these agents slow cognitive decline or disease progression in people with AD or MCI. PubMed, Embase, and Cochrane Central were searched for randomized controlled trials and observational studies of metformin, pioglitazone, or GLP-1 receptor agonists in AD/MCI. Results were synthesized narratively by drug class. Eleven studies met the inclusion criteria. Metformin, particularly in early-stage disease and metabolically vulnerable groups, demonstrated improvements in episodic memory and selective executive outcomes. Observational data in diabetic MCI suggested improved cognition and preservation of hippocampal and cortical structure, with limited amyloid-β and tau changes. Pioglitazone findings varied. Benefits were mainly reported in mild AD with type-2 diabetes, but not in non-diabetic AD/MCI. GLP-1 receptor agonists demonstrated preserved cerebral glucose metabolism and improved blood-to-brain glucose transport but did not improve cognitive function. Current evidence does not support antidiabetic therapies as effective treatments in AD/MCI. Any benefits appear to depend on disease stage and metabolic status, with metformin being the most promising candidate. Larger, longer-duration biomarker-defined trials are needed to determine whether any sustained clinical benefit is observed. Full article

Alzheimer’s disease (AD) is increasingly recognized as a multisystem neurodegenerative disorder in which sensory dysfunction accompanies cognitive decline. As an accessible extension of the central nervous system, the retina provides a valuable window for investigating early neurodegenerative processes; however, the cellular mechanisms underlying AD-associated retinal pathology remain incompletely understood. Here, using the APP/PS1 mouse model, we systematically examined structural, functional, and glial alterations in the retina across disease stages. Despite robust age-dependent amyloid plaque accumulation in visual-related brain regions, no plaque-like β-amyloid (Aβ) deposits were detected in the retina even at advanced ages. Nevertheless, young APP/PS1 mice exhibited early thinning of inner retinal layers, impaired retinal electrophysiological responses, and reduced excitatory synaptic inputs to retinal ganglion cells (RGCs), preceding overt neuronal loss. These neuronal changes were accompanied by pronounced Müller glial activation, characterized by upregulation of gliosis markers and extensive morphological remodeling. Functional analyses further revealed dynamic alterations in glial homeostasis, including early elevation followed by age-dependent decline of glutamine synthetase activity, together with increased expression and disrupted perivascular polarity of aquaporin-4. Consistently, transcriptomic profiling of young AD retinas identified coordinated dysregulation of genes involved in amino acid metabolism, transport, and oxidative stress responses. Together, our findings identify Müller glial remodeling as an early feature of AD-associated retinal pathology that coincides with synaptic vulnerability of RGCs and occurs independently of local Aβ plaque deposition, highlighting retinal glia as potential early indicators and modulators of neurodegeneration. Full article

Alzheimer’s disease (AD) is a multifactorial neurodegenerative disorder characterized by progressive cognitive decline and neuropathological hallmarks such as amyloid-β plaques and neurofibrillary tangles. In recent years, chronic neuroinflammation has emerged as a central mechanism linking genetic, metabolic, and immune dysfunctions in AD. Activated microglia and astrocytes release pro-inflammatory cytokines and reactive oxygen species that exacerbate synaptic and neuronal injury, while impaired clearance mechanisms and blood–brain barrier disruption further sustain inflammation. A growing body of research highlights the role of immunometabolism—the bidirectional interaction between immune activation and cellular metabolism—in shaping glial phenotypes and disease progression. Dysregulation of glucose, lipid, and amino acid metabolism, together with alterations in key metabolites such as lactate, NAD⁺, and reactive oxygen species, promotes a maladaptive inflammatory state. Genetic factors including APOE4 and TREM2 variants affect microglial lipid handling pathways, while systemic metabolic disorders and gut microbiota alterations amplify neuroinflammatory cascades. Natural bioactive compounds, particularly polyphenols, have gained attention for their ability to modulate immunometabolic pathways. By activating AMPK and SIRT1 and inhibiting mTOR and NLRP3 inflammasome signaling, polyphenols may tune mitochondrial function, redox homeostasis, and autophagy, promoting adaptation to chronic metabolic stress. Therefore, metabolic-immune interactions represent pleiotropic therapeutic avenues for AD. Understanding how immunometabolites and nutrient-sensing pathways regulate compartmentalized inflammation in the CNS may pave the way for novel interventions that combine metabolic precision with neuroprotective efficacy. Full article

The proteolytic processing of the amyloid precursor protein (APP) is a core pathological event in Alzheimer’s disease (AD) pathogenesis, yet the global genetic regulatory networks modulating this process have not been fully characterized. To systematically identify novel regulators of APP cleavage, we performed a genome-wide CRISPR/Cas9 knockout screen utilizing an optimized UAS-GAL4-based cellular reporter, and identified genetic modulators governing amyloidogenic and non-amyloidogenic processing. The screen uncovered distinct functional gene clusters regulating the APP, prominently involving cellular metabolism, protein modification, and vesicular trafficking. Specifically, LDHB, PIAS2, CCDC53, and TRIM61 emerged as novel functional modulators. Biochemical validation confirmed that ablating these genes significantly alters the metabolic balance between sAPPα and amyloid-β (Aβ) production. Finally, integration with human AD transcriptomic datasets demonstrated that these identified modulators undergo significant dysregulation in clinics. Together, these findings establish a reporter-based functional screening framework for APP processing and identify candidate regulatory nodes linked to metabolism, protein modification, and vesicular trafficking. These candidates provide a resource for future mechanistic investigation and validation in more disease-relevant AD models. Full article

Neurodegenerative diseases are a serious problem for modern society, and their treatment remains an important issue discussed by the scientific community. One of the promising potential directions for modulating neurodegenerative processes is the use of acylhydrazones, a class of compounds that combine different bioactive fragments linked by an acylhydrazone moiety. So far, the biological properties of these compounds have been proven. They show antibacterial, antiviral, antifungal, antiparasitic, anticancer, anti-inflammatory and antioxidant activity. Many research papers focus on designing acylhydrazones that will find use in the treatment of neurodegenerative diseases by inhibiting the enzymatic activity of acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), β-secretase 1 (BACE1) and monoamine oxidase (MAO), as well as inhibiting β-amyloid aggregation, exhibiting metal chelation and antioxidant properties. Recent studies have described the acylhydrazone-based dual (multi-target) inhibitors, which have demonstrated encouraging outcomes during in vitro evaluations. This review covers recent articles published in the years 2020–2025 and offers a comprehensive overview of the biological properties of the acylhydrazones and their multifunctional derivatives on neurodegenerative processes and/or neuroprotection, while emphasizing their universal nature, structural versatility and role as leading structures in the search for new drugs. Full article

Background: Standardized and ethically compliant animal models remain essential for improving translational research in Alzheimer’s disease. Although Aβ_1–42-induced rodent models are widely used, methodological variability continues to limit reproducibility. Methods: We explored the feasibility of a stereotactic intrahippocampal Aβ_1–42 rat model established by bilaterally injecting pre-aggregated peptide into the hippocampus of adult Sprague Dawley rats. Model feasibility and targeting accuracy were assessed intraoperatively. Cognitive performance was evaluated using the Y-maze for spatial recognition memory and the novel object recognition (NOR) test. Histological examination was performed using hematoxylin–eosin (H&E) and Congo red staining to assess cytoarchitecture and to provide supportive evidence of amyloid-like deposits. Results: The surgical procedure was well-tolerated, and the injected animals showed reduced performance in behavioural testing, including reduced spatial recognition memory in the Y-maze and decreased discrimination indices in the NOR test. The animals also showed histological changes, including Congo red-positive birefringent structures consistent with amyloid-like congophilic material. Conclusions: This study presents a feasible experimental framework for intrahippocampal Aβ_1–42 administration, showing behavioural and histological changes under the present experimental conditions. However, further validation, including sham-operated controls and molecular characterization, will be required before these findings can be interpreted as specific to Aβ-driven pathology. Full article

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder classically defined by cerebral amyloid-β (Aβ) plaque deposition and tau pathology. In recent years, AD has increasingly been recognized as a multisystem disorder rather than a purely brain-restricted condition, as mounting evidence indicates that Aβ metabolism is a dynamic, bidirectional process involving both central and peripheral compartments. Peripheral tissues, particularly platelets, liver, kidneys, and the gastrointestinal tract, contribute substantially to circulating Aβ levels and influence cerebral amyloid burden. Platelets are now considered the predominant source of peripheral Aβ, accounting for the majority of plasma Aβ under physiological and pathological conditions, while the liver and kidneys play critical roles in Aβ clearance through receptor-mediated uptake, enzymatic degradation and excretion. Disruption of these peripheral clearance pathways elevates circulating Aβ, increasing its transport into the brain via blood–brain barrier (BBB) mechanisms by enhanced RAGE-mediated influx and impaired LRP1-dependent efflux in AD. Peripheral Aβ entry into the central nervous system exacerbates neuroinflammation, mitochondrial dysfunction, and oxidative stress, thereby accelerating neuronal damage and disease progression. This review synthesizes updated evidence on peripheral sources of Aβ, differences between central and peripheral Aβ pools, mechanisms of Aβ transport across the BBB, pathological consequences of peripheral Aβ on the brain and emerging therapeutic strategies targeting peripheral Aβ metabolism, highlighting the importance of a systemic perspective in AD pathogenesis and treatment. Full article

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder in which amyloid β accumulation, tau pathology, chronic neuroinflammation, and metabolic stress converge to drive synaptic dysfunction and neuronal loss. Rather than resulting from a single mechanism, increasing evidence indicates that neurodegeneration in AD is mediated by the coordinated activation of multiple regulated cell death pathways. These pathways include apoptosis, necroptosis, pyroptosis, ferroptosis, and autophagy-dependent cell death, each characterized by distinct molecular mediators and execution programs. Evidence from human brain tissues, animal models, and in vitro systems demonstrates that core pathological drivers such as amyloid β and tau pathology, oxidative stress, and sustained neuroinflammation engage these death pathways in a spatially, temporally, and cell-type-dependent manner across neurons and glial populations. In this review, we synthesize the current knowledge on regulated cell death mechanisms in AD, emphasizing their molecular signatures, cellular specificity, and stage-dependent involvement, together with recent advances in immunohistochemical, imaging, and biofluid-based approaches for detecting neuronal death. By integrating evidence across molecular, cellular, and system levels, this review positions regulated cell death as a unifying framework for understanding neurodegeneration and developing pathway-specific biomarkers and combinatorial neuroprotective strategies. Full article

The central nervous system (CNS), comprising the brain and spinal cord, represents the core regulatory hub of the body. Damage to the CNS often leads to irreversible structural and functional impairments of neural tissues, posing a major global public health challenge. Immune memory encompasses two states: immune training and immune tolerance, which are characterized by enhanced or attenuated immune responses, respectively, following initial exposure to external stimuli in immune cells such as monocytes and macrophages. Microglia, the resident immune cells of the CNS, can be rapidly activated by external stimuli. Accumulating evidence indicates that microglial immune memory plays a critical role in sustaining states and neuroinflammatory responses in CNS disorders. Specifically, the immune training state promotes amyloid-β (Aβ) accumulation in the brains of Alzheimer’s disease (AD) model mice, thereby exacerbating neuronal damage, whereas the immune tolerance state suppresses pro-inflammatory cytokine expression and alleviates neuroinflammation. This review focuses on two immune memory states in microglia—training and tolerance—and what triggers them. We summarize their roles and mechanisms in CNS diseases. Specifically, we break down how epigenetic and metabolic reprogramming control microglial immune memory, with an emphasis on how these two processes interact during memory formation and maintenance. Our goal is to fill key knowledge gaps about their combined effects and to suggest new therapeutic targets. Evidence shows that immune memory acts as a “double-edged sword” in the CNS: it can either fuel harmful inflammation and worsen damage, or, when moderately activated, protect nerves. Therefore, precisely balancing these two states could help reduce harmful inflammation while preserving the protective functions of microglia, offering a new, reversible immunotherapy for CNS diseases. Full article