Search Results (1,617)

Background: Early endolysosomal and autophagic defects are among the earliest cellular alterations observed in Alzheimer’s disease (AD). However, the molecular mechanisms linking amyloid precursor protein (APP) metabolism to vesicle trafficking dysfunction remain incompletely understood. The APP-derived fragment C99 has emerged as a potential upstream mediator of intracellular toxicity, but its impact on organelle homeostasis and its modulation by metabolic interventions remain unclear. Methods: To investigate these mechanisms, we expressed human C99 in Drosophila neurons and examined intracellular pathology using ultrastructural analysis, fluorescent reporters of autophagy and mitochondrial turnover, and proteomic interactome mapping. The effects of the ketone body β-hydroxybutyrate (BHB) were evaluated to assess the impact of metabolic intervention. Results: Neuronal C99 expression induced pronounced vesicular abnormalities, impaired autophagic turnover, and disrupted mitochondrial quality control. Transmission electron microscopy revealed extensive accumulation of enlarged vesicular compartments, accompanied by reduced mitochondrial turnover and accumulation of aged mitochondria. BHB treatment restored autophagic cargo clearance, improved mitochondrial turnover, and normalized vesicular ultrastructure. These protective effects required neuronal ketone transport, indicating a neuron-intrinsic metabolic mechanism. Proteomic analysis of the C99-associated interactome revealed that ketone treatment remodels networks enriched for vesicle trafficking and proteostasis pathways. Network prioritization identified the retromer component VPS35 as a candidate regulatory hub. Functional analyses demonstrated that depletion of VPS35 abolished the BHB-dependent restoration of autophagy, mitochondrial turnover, and vesicle morphology. Conclusions: Ketone treatment restores mitochondrial quality control and autophagic homeostasis through a VPS35-dependent mechanism in C99-induced neurodegeneration. These findings provide mechanistic insight into how metabolic interventions may restore intracellular homeostasis in Alzheimer’s disease. Full article

Chronic depression is associated with oxidative stress, neuroinflammation, neurotransmitter imbalance, and Alzheimer’s-like changes. Current monoamine oxidase inhibitors have limited cognitive benefits and disease-modifying properties. A new nanotherapeutic, combining chitosan nanoparticles, propargylamino-1-(4-methylthiophenyl) propane (PAMTP), and L-tyrosine (En@PAMTP_Tyr), was developed. En@PAMTP_Tyr nanoparticles were ~140 nm in diameter, with a zeta potential of +27 mV and entrapment efficiencies of 73.45% for PAMTP and 90.85% for L-tyrosine. Drug release was pH-sensitive, favoring acidity. Intraperitoneal administration of En@PAMTP_Tyr reduced anhedonia, despair, cognitive deficits, and neuromuscular weakness, with efficacy matching or exceeding that of selegiline. In treated rats’ hippocampal tissue, En@PAMTP_Tyr increased superoxide dismutase and glutathione, normalized MAO and acetylcholinesterase activities, and corrected CUSD-induced TNF-α and IL-10 changes, showing antioxidant and anti-inflammatory effects. Histological analyses revealed that En@PAMTP_Tyr preserved CA1 pyramidal neurons, reduced β-amyloid levels, restored tau protein, and improved brain-derived neurotrophic factor levels, indicating reduced neurodegeneration. Molecular docking studies showed that PAMTP had high affinity for monoamine oxidase and acetylcholinesterase, supporting its role as an MAO-B inhibitor and cholinergic modulator. These findings suggest that En@PAMTP_Tyr is a promising nanoplatform for targeting MAO-B in depression, addressing mood, cognitive function, oxidative stress, inflammation, and Alzheimer-like pathology in the hippocampus. Full article

Alzheimer’s disease (AD) is associated with the aggregation and deposition of amyloid-β (Aβ), making Aβ aggregation an important target in AD-related research. Food-derived components have attracted attention as potential modulators of Aβ-related processes, but the direct effects of diverse food samples on Aβ42 aggregation remain unclear. Here, we screened 120 food-sample preparations derived from 115 food items for inhibitory activity against Aβ42 aggregation using an automated microliter-scale high-throughput screening system with quantum-dot-labeled Aβ (QDAβ). Among primary screening samples, 34 showed detectable Aβ42 aggregation-inhibitory activity, and 12 were classified as highly active (1/EC₅₀ ≥ 10 mL/mg). Within the present screening set, highly active samples were frequently observed among tea-related samples. Black tea, Camembert, Red perilla, and Black soybean were selected as representative hits for further validation. Automated MSHTS images and dose–response data showed concentration-dependent suppression of Aβ42 aggregate formation. These inhibitory effects were further supported by thioflavin T (ThT) assays and transmission electron microscopy, which showed suppression of ThT-positive fibrillar aggregation and reduced fibrillar aggregate formation. In differentiated PC12 cells, selected food samples increased cell viability in Aβ42-treated cells at some concentrations. These findings provide a basis for functional food research and active component analysis of food-derived Aβ42 aggregation modulators. Full article

Background:/ Over the past decade, increasing evidence has shifted attention from the brain to the gut microbiota (MB) as a source and site of systemic dissemination of amyloid-β (Aβ), an APP derivative responsible for plaque formation in the brains of Alzheimer’s disease (AD) patients. Furthermore, AD patients and APP/PS1 mice, a transgenic model of AD, exhibit dysbiosis. Objectives: Using APP/PS1 mice treated from 2 to 8 months of age, we studied ileal and colonic epithelial integrity, intestinal barrier (IB) integrity assessed through tight junction (TJ) protein expression, local immune system, the presence/increase in Aβ expression in enterocytes, and the protective effects of synbiotic treatment. Methods: The tissue was stained with Periodic Acid-Schiff and Alcian Blue to evaluate epithelial morphology and mucus production, and immunohistochemistry was performed to assess TJs, immune markers, and Aβ expression. Results: Our results demonstrate that colonic and ileal epithelium of 8-month-old APP/PS1 mice displays IB impairment in term of alterations of goblet cells staining and TJ protein expression and signs of immune involvement. The ileum was more severely affected, showing a reduced epithelial surface area, decreased lysozyme production, and fewer tuft cells. Long-term synbiotic treatment largely prevented APP/PS1 mouse changes and caused a significant increase in Aβ expression in all treated mice. Conclusions: These findings support the belief in early intestinal involvement in AD and highlight the potential of the microbiota as a target for early intervention aimed at modifying the progression to neurodegeneration. Increased epithelial Aβ labeling after treatment raises the possibility of intestinal management of Aβ, which requires further validation. Full article

6PPD is a widely used tire antioxidant that readily transforms into its more toxic ozonation product, 6PPD-quinone (6PPD-Q). Both compounds are emerging environmental contaminants with potential neurotoxic risks, yet their molecular mechanisms in Alzheimer’s disease (AD) and Parkinson’s disease (PD) remain unclear. This study integrated network toxicology, molecular docking, transcriptomic validation, and experimental models to investigate their neurotoxic effects. In silico analyses predicted significant neurotoxicity and blood–brain barrier permeability for both compounds. Target prediction and PPI network analysis identified 145/121 overlapping targets with AD/PD for 6PPD and 120/100 for 6PPD-Q. Functional enrichment analysis suggested that 6PPD-associated targets were mainly enriched in axon regeneration-, p75NTR-, and AGE-RAGE-related pathways, whereas 6PPD-Q-associated targets were enriched in MAPK cascade-, endosomal TLR signaling-, and amyloid-β formation-related pathways. Molecular docking suggested favorable binding affinities between these compounds and several core targets, including MAP2K1, EGFR, GSK3B, and CYCS. Transcriptomic validation in GEO datasets prioritized multiple hub genes. In vivo experiments showed activation of apoptosis-related signaling in the brain, while in vitro assays demonstrated ROS accumulation and neuroinflammatory activation (elevated TNF-α, IL-1β, IL-6, IFN-γ). CYCS and MAP2K1 emerged as key convergent nodes. Our findings reveal distinct yet synergistic neurotoxic mechanisms of 6PPD and 6PPD-Q in AD and PD, highlighting tire-derived pollutants as potential environmental risk factors for neurodegenerative diseases. Full article

Alzheimer’s disease (AD) is a complex neurodegenerative disorder with features of amyloid-beta (Aβ) accumulations, tau hyperphosphorylation, oxidative stress, neuroinflammation, and synaptic losses. Despite extensive therapeutic investigations for many decades, the clinical treatment options remained largely symptomatic, while anti-amyloid antibody therapies were expensive and had limited accessibility. A subclass of triterpenoids generated from plants, pentacyclic triterpenic acids (PTAs), exhibited a variety of pharmacological properties. The neuroprotective effects of some important PTAs in AD models were reviewed in this study. These phytochemicals displayed a multimodal neuroprotection by lowering amyloid and tau, improving mitochondrial function, inhibiting inflammation, and improving synaptic plasticity and cognition. However, the neuroprotective mechanisms of several PTAs remained poorly characterized. In addition, most evidence were preclinical, while poor bioavailability and the limited clinical validation hindered the therapeutic translation. Studies were needed to evaluate these phytochemicals in AD, improve their pharmacokinetics, and enhance brain delivery. Their diverse bioactivities and encouraging preclinical findings suggest these compounds may serve as promising lead candidates for future drug development in neurodegenerative diseases. Full article

Alzheimer’s disease (AD), the leading cause of dementia, is characterized by progressive cognitive decline along with hallmark brain pathologies including amyloid-beta accumulation, hyperphosphorylated tau, neuroinflammation and neuronal mitochondrial dysfunction. As current pharmaceutical treatments only provide modest symptomatic improvement, there is an urgent need for effective non-pharmaceutical treatment options for the prevention or slowing down of this disease. This review synthesizes results from randomized controlled trials, observational studies, and animal model research on the ability of exercise to influence cognitive functions, brain structural changes, inflammatory processes, and neuroplasticity-related pathways. Exercise has demonstrated the capacity to enhance neurotrophic signaling, improve the regulation of mitochondria, improve cerebrovascular function and reduce pro-inflammatory cytokine levels in preclinical and mild cognitive impairment (MCI) subjects. Additionally, aerobic and resistance training has been shown to enhance physical performance and functional capacity. Furthermore, mind–body, dual-task and multimodal types of interventions may also provide additional cognitive and psychological benefits. Although the overall cognitive effect of exercise in individuals with established AD is generally small, it has been demonstrated that exercise can contribute to maintaining brain health through multiple interconnected metabolic, vascular and molecular pathways, thereby preserving cognitive reserve and slowing disease progression, particularly when initiated during early to midlife prior to the onset of AD symptoms. Therefore, future research will require establishing stage-specific exercise recommendations based on modality type, intensity and duration to achieve optimal clinical outcomes. Full article

Background/Objectives: Alzheimer’s disease (AD) is characterized by beta-amyloid (Aβ) plaque deposition, which impairs several cellular processes, including autophagy. Considering the multifactorial nature of AD, the development of therapies acting on alternative molecular targets is necessary. In this study, we evaluated the neuroprotective effect of a molecule from the hydrozoan Eudendrium carneum and investigated its impact on autophagy-related pathways. Methods: The secretion of E. carneum was fractionated by RP-HPLC according to its neuroprotective activity in SH-SY5Y cells exposed to oAβ42, evaluated using LDH and MTT assays. The purified molecule (named EC5), characterized by mass spectrometry, was evaluated regarding in silico toxicity and calcium dynamics. Neuronal lysosomal morphology was assessed using the LysoTracker probe, and cathepsin D activity was determined using a synthetic substrate. The expression of autophagy-related proteins (mTOR, LAMP-1, and LC3B) was evaluated by dot blotting, and amyloid plaque clearance was quantified using Thioflavin-T staining. Results: The steroid glycoside putatively identified as Sarmentoside B (EC5) exhibited neuroprotective effects and showed no toxicity or alterations in neuronal calcium or sodium channel dynamics. EC5 restored lysosomal morphology and cathepsin D activity, reversing the impairment induced by oAβ42. Furthermore, EC5 reduced mTOR expression, and this interaction was supported by molecular docking analysis. Lysosomal restoration promoted the clearance of oAβ42 aggregates, as evidenced by Thioflavin-T staining, resulting in reduced neuronal death. Conclusions: EC5, putatively identified as Sarmentoside B, exerts neuroprotective effects against oAβ42-induced toxicity by promoting autophagy-related amyloid clearance, highlighting its therapeutic potential for AD. Full article

While amyloid precursor protein (APP) overexpression in adipose tissue is a recognized consequence of high-fat diet (HFD) feeding, its role in metabolically active organs and the mechanisms linking it to systematic dysfunction remain unclear. In particular, the potential for diet-induced APP dysregulation in the other tissues and the contribution of its βC-terminal fragment (βCTF) are poorly characterized. Using a high-fat diet (HFD) mouse model to induce systematic metabolic stress, we assessed APP and βCTF levels across multiple tissues. HFD triggered a tissue-specific response, with APP levels increasing >2-fold in visceral and subcutaneous white adipose tissue (WAT) and in the kidney but remained unchanged in the liver and brain. βCTF levels were significantly elevated in the visceral WAT (3-fold) and kidney. In these responsive tissues, APP and βCTF accumulated within mitochondria, which coincided with significantly reduced complex I and IV activities. Complementary in vitro studies confirmed that APP levels can dictate mitochondrial function. Furthermore, we identified that cytokines–IL-4, IL-13, TNF-α, and IL-1β–induced APP transcription, providing a mechanistic link between diet-induced inflammation and APP dysregulation. Collectively, our findings demonstrate that APP is overexpressed in response to HFD in select peripheral tissues, which coincides with reduced mitochondrial complex enzyme activities and increased cytokine levels. Full article

Sodium–glucose cotransporter-2 (SGLT2) inhibitors, initially developed as antidiabetic agents, have recently gained attention for their potential role in modulating processes relevant to Alzheimer’s disease (AD). Preclinical studies suggest that they may influence key mechanisms involved in AD. However, available clinical studies, mainly retrospective and focused on diabetic populations, provide insufficient clarity on whether these effects extend to broader, non-diabetic groups. The heterogeneity of neurodegenerative diseases, which differ in inflammatory and proteotoxic mechanisms, further highlights the need for disease-specific investigations. This review examines mechanistic pathways through which SGLT2 inhibition may influence AD progression and evaluates current clinical evidence, aiming to identify key knowledge gaps and guide future research. This review summarises the latest evidence from the literature, focusing on preclinical experiments, translational studies and early clinical observations. The search focused on pathways related to microglial and astrocytic activation, oxidative stress, metabolic remodeling, neuronal survival, and amyloid and tau dynamics. Accumulating data indicate that SGLT2 inhibitors exert multifaceted actions relevant to AD pathology, including reduced neuroinflammation and oxidative stress, improved mitochondrial and insulin signaling, as well as decreased amyloid deposition and tau hyperphosphorylation. Additionally, SGLT2 inhibition may improve cerebrovascular perfusion and blood–brain barrier stability, potentially supporting cognitive function. Nonetheless, major challenges remain, including variable blood–brain barrier permeability and heterogeneous experimental responses. SGLT2 inhibitors represent a promising pleiotropic class of compounds with potential disease-modifying effects in AD. Their capacity to target metabolic, inflammatory, and proteotoxic pathways makes them attractive candidates for neurodegenerative therapy. Further studies are required to clarify biochemical pathways and validate clinical efficacy. Full article

Alzheimer’s disease (AD) is characterized by the accumulation of amyloid-β (Aβ) and chronic neuroinflammation, with microglia playing a central role in its pathogenesis. Alterations in microglial metabolism have been proposed to contribute to AD-related inflammatory responses and reduced Aβ clearance, suggesting that thiamine-dependent pathways may be relevant in this context. Thiamine pyrophosphate (TPP), the active form of vitamin B1, is essential for glucose metabolism and mitochondrial function; however, its association with microglial changes in AD remains unclear. In this study, 9-month-old female triple-transgenic AD (3xTg-AD) mice and non-transgenic controls (NoTg) received TPP (2.0 mg/mL) or saline as a vehicle for six weeks via osmotic pumps. Nesting, a hippocampus-dependent behavioral test, as well analyses of Aβ burden, microglial morphology, and the expression of genes related to metabolic and immune pathways were evaluated. Differences in nesting behavior between experimental groups were observed, but TPP treatment was not associated with an evident change in 3xTg-AD mice. In the subiculum and CA1 regions of the hippocampus of female 3xTg-AD mice exposed to TPP, a lower Aβ burden was observed, and morphological variations in microglia were detected in both groups (3xTg-AD and NoTg). Additionally, in the brain of the TPP-treated group, some changes in mRNA gene expression were recorded. Together, these findings describe hippocampal microglial and amyloid profiles following TPP treatment in 3xTg-AD mice and provide a basis for further investigation of thiamine-dependent pathways in AD-related neuroinflammatory contexts. Full article

Dietary polyphenols such as quercetin, resveratrol, and (−)-epigallocatechin-3-gallate (EGCG) have shown neuroprotective effects in epidemiologic and experimental studies of Alzheimer’s disease (AD), although clinical evidence remains limited. This review highlights the importance of investigating glucuronide and sulfate conjugates of these polyphenols, as well as their intestinal microbial metabolites, at bioavailable low nanomolar concentrations, particularly those capable of reaching the brain. Although many in vitro studies use micromolar concentrations of aglycones, the relevance of such concentrations to neuroprotection remains uncertain. While polyphenols are redox-sensitive, their direct antioxidant or prooxidant effects may be limited at nanomolar concentrations. Instead, their neuroprotective actions appear to be mediated through high-affinity interactions with molecular targets such as the 67-kDa laminin receptor (67LR). This receptor binds both aglycones and conjugates at low nanomolar concentrations through a peptide G region containing glycosaminoglycan- and palindromic sequence-related motifs. The same region also binds the prion–amyloid-β complex, suggesting that polyphenols may antagonize amyloid-β binding and thereby prevent its neurotoxicity. The peptide G region may also function as a redox sensor. Binding of polyphenols to 67LR activates cAMP signaling and downstream neuroprotective pathways involving CREB, SIRT1, and protein phosphatase 2A. In addition, nanomolar concentrations of resveratrol and quercetin inhibit quinone reductase 2, an enzyme associated with cognitive decline and reported to be elevated in AD. Given their low bioavailability in the brain and their distinct molecular targets, combining multiple polyphenols at low doses may produce additive or synergistic effects, enhance efficacy, and minimize potential toxicity in the prevention of AD. Full article

The pathological progression of Alzheimer’s disease (AD) involves not only intrinsic neuronal lesions but is also closely associated with dysregulation of intercellular communication within the neuroimmune microenvironment. Glycolysis, as a central pathway in cellular energy metabolism, exhibits significant abnormalities in AD, and changes in its activity may further influence disease progression by modulating interactions between neurons. This article aims to systematically elucidate how glycolysis, as a key component of metabolic regulation, participates in the regulation of cellular interactions during the progression of AD, and to explore its potential mechanisms and therapeutic implications. Firstly, it systematically reviews the key changes in interactions between cells in AD, including microglia, astrocytes, oligodendrocytes, and neurons, and their roles in neuroinflammation, synaptic loss, and amyloid deposition. Secondly, by analysing alterations in the glycolytic metabolic profiles of various neuronal cell types in AD, we explore in depth how glycolysis regulates cellular signalling, inflammatory responses, and cellular function, thereby influencing cell–cell interactions. Lastly, by combining current research on the control of the glycolytic pathway in AD with possible therapeutic methods, we propose a novel way to stop the progression of the disease by focusing on cell interactions through mediating glycolysis. By tracing the causal chain in AD through which glycolysis acts as a bridge via altered cell–cell interactions, this paper aims to provide a theoretical basis for the development of disease-modifying therapies based on metabolic reprogramming. Full article

Purpose: The aim of this study was to compare the contributions of putative glymphatic-related imaging indices—diffusion-weighted image analysis along the perivascular space (DWI-ALPS) index and choroid plexus volume (CPV)—and total cortical gray matter volume (TCGMV) to cognitive function in cerebral amyloid angiopathy (CAA). Methods: Forty-four CAA patients and 22 controls underwent 3.0T MRI. Cognitive function was assessed by the Mini-Mental State Examination (MMSE). The mean DWI-ALPS index, CPV/intracranial volume (ICV), and TCGMV/ICV were compared between groups; hierarchical multivariable regression and mediation analyses evaluated MMSE correlates. Results: Compared with controls, CAA showed a lower mean DWI-ALPS index and TCGMV/ICV (both adjusted p < 0.05), whereas CPV/ICV did not differ significantly after adjustment. In hierarchical multivariable regression analysis, mean DWI-ALPS index was associated with MMSE before adjustment for TCGMV/ICV (p = 0.022), but this association was attenuated after TCGMV/ICV was added to the model (p = 0.665). CPV/ICV was not associated with MMSE in either model, whereas TCGMV/ICV was independently associated with MMSE (p = 0.013). Exploratory mediation analysis suggested an indirect association between mean DWI-ALPS and MMSE via TCGMV/ICV (indirect: p = 0.023; direct: p = 0.720). Conclusions: Cortical atrophy appeared to be the strongest imaging correlate of cognitive impairment in CAA, while the association between DWI-ALPS and MMSE in multivariable models was attenuated after accounting for cortical gray matter volume. The ALPS index may provide indirect information on glymphatic-related pathways, but its biological specificity in CAA requires cautious interpretation because ALPS measurements may be influenced by underlying microstructural alterations in white matter. Full article

Glucose is the principal energy substrate for the brain. Hypo- and hyperglycemic episodes frequently occur in senescent people, contributing to functional and structural impairment of brain neurons and causing cognitive deficits in this population. In this study, we investigate whether long-term changes in the extracellular concentration of glucose affect viability and transmitter functions of septum-derived SN56 cholinergic neuronal cells through alterations in acetyl-CoA availability. Cells with low cholinergic expression (NCs) and cAMP/retinoic acid-induced high cholinergic expression (DCs) were investigated. Hypoglycemia brought about similar (approximately 20–30%) decreases in pyruvate dehydrogenase complex (PDHC) and ATP-citrate lyase (ACLY) activities and a 65% decline in lactate dehydrogenase (LDH) activity in NCs and DCs. Choline acetyltransferase (ChAT) and LDH activities in DCs were about 3–8 and 1.7–2.4 times higher than in NCs over the tested glucose concentration range, respectively. DCs appeared to be more resistant than NCs to hypoglycemia, as evidenced by lower glucose IC₅₀ values for cell count and intracellular LDH activity. On the other hand, some of functional properties of DCs, such as the cholinergic phenotype and their plasma membrane functions (trypan blue exclusion, TB+), were found to be more sensitive to hypoglycemia than those of NCs, as demonstrated by the higher IC₅₀ for glucose in DCs. Acetyl-CoA levels in DCs were 40% lower than in NCs, and decreased by about 25% with increasing hypoglycemia in both cell types. The cytotoxic effects of amyloid-β_25–35 (Aβ) and sodium nitroprusside (SNP; NO generator) were also tested. In 25 mM glucose medium, these toxic compounds exerted greater detrimental effects on DCs than on NCs. In contrast, in 1 mM glucose, more evident cytotoxicity of SNP and Aβ was observed in NCs. These data suggest that the higher rate of glycolysis in differentiated cholinergic septal neurons may be a protective mechanism against hypoglycemia. Full article