👤 Yeojin Choi

Current therapeutic approaches for Alzheimer's disease (AD) demonstrate limited efficacy and fail to address disease progression. In the present study, we present HSN-G1, a novel ginsenoside-enriched pharmaceutical formulation that employs a dual-target mechanism through the modulation of amyloid clearance pathways and cholinergic neurotransmission. HSN-G1 demonstrates a reproducible ginsenoside profile enriched with Re (33.27 mg/g), Rd (25.00 mg/g), and Rg3 stereoisomers (12.18 mg/g), ensuring pharmaceutical-grade reproducibility. HSN-G1 enhanced amyloid-beta (Aβ) clearance in microglial cells, with significantly greater effects observed in SRA-overexpressing cells, suggesting SRA-dependent clearance mechanisms. In APP/PS1 transgenic mice, six-week oral administration of HSN-G1 (100-400 mg/kg) elicited significant dose-dependent improvements in cognitive performance. Male mice exhibited more stable and consistent enhancements in both passive avoidance and spatial memory tests compared to vehicle controls (p < 0.001), while both sexes demonstrated comparable reductions in brain Aβ levels (approximately 45%) and differential increases in acetylcholine (73% in males; 55% in females, p < 0.01). HSN-G1 administration enhanced the expression of neurotrophic factors, with NGF upregulation predominantly observed in males, whereas BDNF, CNTF, and GDNF were consistently elevated across both sexes. These findings establish HSN-G1 as a promising disease-modifying agent with standardized composition and therapeutic efficacy, surpassing the limitations of conventional single-target approaches. The superior efficacy of HSN-G1 compared to existing treatments validates its potential for clinical development, highlighting the significance of sex-specific therapeutic responses in future AD therapeutics. Show less

Cholinergic dysfunction is a key contributor to cognitive impairment observed in aging and neurodegenerative disorders such as Alzheimer's disease (AD). Although acetylcholinesterase (AChE) inhibitors have been the mainstay of symptomatic treatment for over two decades, their limited efficacy and adverse effects underscore the need for alternative therapeutic approaches. Recent evidence indicates that mechanical stimulation can modulate neuronal and glial signaling through mechanotransduction, suggesting a potential strategy to enhance cognitive function via non-pharmacological means. Here, we developed a head-mounted vibrotactile stimulation system (HVSS) that delivers controlled vibration to the cranium and evaluated its effects in a pharmacological model of acute cholinergic dysfunction induced by scopolamine. To this end, male C57BL/6 mice received scopolamine (1 mg/kg, i.p.; on days 7, 14, and 28) and were exposed to daily vibrotactile stimulation at 20, 40, or 80 Hz for 28 days. Behavioral performance was assessed using passive avoidance and Morris water maze tests, followed by biochemical and histological analyses. HVSS at 40 Hz and 80 Hz significantly improved cognitive performance, enhanced hippocampal cholinergic function, reduced oxidative damage, and upregulated memory-related signaling genes, including BDNF, PI3K, AKt, ERK1/2, CREB, and CAMK4. These findings suggest that high-frequency HVSS improves memory hippocampal cholinergic function via activation of memory-related signaling pathways, highlighting its potential as a safe, non-pharmacological neuromodulatory strategy for cholinergic dysfunction-related cognitive decline. Show less

Inflammatory bowel disease (IBD) is a chronic gastrointestinal disorder with a high incidence of anxiety and depression. However, the underlying mechanisms of these symptoms remain to be fully elucidated. This study investigated the effects and mechanisms of a 20% ethanolic extract of Show less

Neurodegenerative and mental disorders impose significant global disease burdens and pose serious social and economic challenges. Physical exercise (PE) exerts beneficial effects on brain health, contributing to a reduction in the risk of Alzheimer's disease (AD), Parkinson's disease (PD), depression, anxiety, and post-traumatic stress disorder (PTSD). To understand these effects of PE, a variety of molecules released from various tissues in response to PE have been discovered, which are collectively called 'exerkines'. In particular, the skeletal muscle acts as an endocrine organ, secreting exerkines and is included in the category of myokines that facilitate direct or indirect crosstalk between the muscle and the brain. Although muscles actively interact with organs such as the liver, pancreas, and adipose tissue, the precise mechanisms of muscle-brain communication have yet to be fully elucidated. In the skeletal muscle, the types of exerkines secreted and their effects vary depending on the PE modality. Furthermore, these exerkines can cross the blood-brain barrier (BBB) to exert direct effects or act indirectly Show less

Aging disrupts the neurovascular unit (NVU) and blood-brain barrier (BBB), elevates glial inflammatory tone, and compromises hippocampal memory. Environmental enrichment (EE)-a multimodal, lifestyle-based intervention-improves cognition, but its association with BBB/NVU and FNDC5/irisin-related signaling in aging remains incompletely understood. Aged male C57BL/6J mice (21 months old) were housed under EE or standard conditions for 11 weeks. Hippocampal-dependent spatial working memory was assessed using the radial eight-arm maze, and neuronal (NeuN), glial (Iba1, GFAP), and BBB/NVU markers (AQP4 endfoot polarity, occludin, ZO-1, PECAM-1, microvessel length/density) were quantified. FNDC5/irisin-related signaling was evaluated by measuring PGC-1α, FNDC5/irisin, IGF-1, BDNF, Show less

Ischemic stroke triggers hypoxia, inflammation, and oxidative stress. Local oxygen delivery may prevent secondary injuries. Herein, we implanted a catalase-incorporated thiolated gelatin-based oxygen-releasing hydrogel sheet in a rat model of photothrombosis to evaluate early infarct attenuation and feasibility. Male Sprague-Dawley rats were allocated to four groups (n = 6/group): control at 24 h (G1), with hydrogel sheet at 24 h (G2), control at 72 h (G3), and with hydrogel sheet at 72 h (G4). Focal ischemia was induced with Rose Bengal and targeted illumination through a 6.0-mm cranial defect. A hydrogel sheet was applied to the cortex after surgery. The infarct burden was assessed by 2,3,5-triphenyltetrazolium chloride (TTC) staining and magnetic resonance imaging (MRI), while mRNA expression levels of tumor necrosis factor-α (TNF-α), brain-derived neurotrophic factor (BDNF), and superoxide dismutase (SOD) were measured by quantitative reverse transcription PCR. Body weight was monitored as a safety measure. At 24 h, TTC showed a significant infarct reduction in G2 compared with G1. At 72 h, infarct measures did not differ significantly between G4 and G3. MRI and gene expression analyses did not show statistically significant between-group differences and are presented as exploratory outcomes. Weight and perioperative status were similar across groups, indicating short-term tolerability. The hydrogel sheet was associated with reduced TTC-defined infarct burden at 24 h in this model; confirmatory studies will require larger, powered cohorts, longer follow-up with functional testing, and in vivo oxygen release profiling to optimize dose, placement, and exposure time. Show less

Euglena gracilis has a history of traditional use in East Asia as a functional food with reported antioxidant and immunomodulatory benefits. This study investigates the pharmacological potential of its bioactive component, standardized alkali-treated β-glucan (AEGB), in mitigating systemic toxicity induced by environmental pollutants, providing a rationale to investigate its protective effects in the context of particulate matter (PM2.5)-induced injury. To evaluate the protective effects of standardized alkali-treated E. gracilis β-glucan (AEGB) against PM2.5-induced pulmonary and cerebral toxicity in BALB/c mice via the lung-brain axis. AEGB was prepared and standardized to contain 93% (w/w) β-glucan. BALB/c mice were intranasally exposed to PM2.5 and orally administered AEGB (200/400 mg/kg). Efficacy was evaluated via BALF analysis, histopathology, and immunoblotting, focusing on MAPK, NF-κB, NRF2-HO-1, and CREB-BDNF-TrkB pathways. AEGB exhibited higher antioxidant activity than untreated β-glucan. In PM2.5-exposed mice, AEGB (400 mg/kg) reduced inflammatory cells in BALF by 69.5% and suppressed lung pro-inflammatory cytokines (IL-1β, IL-6). Histologically, it attenuated bronchial thickening and mucin production. In the brain, AEGB downregulated NF-κB by 72.1% and restored hippocampal neuronal area (+41.1%) and tight junction marker expression associated with blood-brain barrier integrity. At the molecular level, AEGB inhibited pulmonary MAPK/NF-κB and activated NRF2-HO-1, while enhancing the cerebral CREB-BDNF-TrkB neurotrophic pathway. AEGB mitigates PM2.5-induced damage in both lung and brain tissues, accompanied by anti-inflammatory and neuroprotective responses consistent with inter-organ inflammatory/oxidative pathways relevant to the lung-brain axis. These findings validate the potential of E. gracilis-derived β-glucan as a functional agent for preserving respiratory and neural health. Show less

Alzheimer's disease (AD) is characterized by progressive cognitive decline and memory dysfunction, with prominent roles in cholinergic deficits and synaptic plasticity impairments. Vitisin B, a resveratrol tetramer derived from Vitis vinifera, exhibits potent antioxidant and neuroprotective properties. However, its potential to influence cognitive function in AD models remains inadequately explored. In this study, we first tested vitisin B in an in vitro model using SH-SY5Y cells exposed to scopolamine-induced cytotoxicity, where vitisin B significantly enhanced cell viability and promoted cell survival. We evaluated its therapeutic potential in vivo using both systemic administration and direct delivery into the third ventricle of the brain in a scopolamine-induced AD mouse model. Across both administration routes, vitisin B exerted a broad pro-cognitive effect, restoring multiple domains of learning and memory disrupted by scopolamine. Vitisin B recovered spatial working memory in the Y-maze, normalized exploratory activity in the open field, improved recognition memory in the novel object recognition (NOR) test, and enhanced long-term memory retention in the passive avoidance assay. This treatment restored cognitive function, alleviated cholinergic deficits, increased hippocampal brain-derived neurotrophic factor (BDNF) levels, and enhanced synaptic plasticity. These results suggest that vitisin B exerts reliable cognitive and neuroprotective effects through both systemic and cerebral administration, highlighting its potential as a promising therapeutic compound for restoring cholinergic function and enhancing hippocampal synaptic plasticity in AD. Show less

Computerized cognitive training allows real-time tracking of performance metrics that may serve as digital biomarkers. This study investigated the value of a novel in-game digital biomarker, RTACC (Reaction Time-Accuracy Correlation), the correlation between reaction time and accuracy, using data from 130 participants with mild cognitive impairment enrolled in the intervention arm of the SUPERBRAIN-MEET randomized controlled trial. Participants underwent a 24-week multi-domain intervention, consisting of computerized cognitive training, physical exercise, nutritional education, vascular/metabolic risk management, and motivation enhancement. RTACC was derived from task-level RT and accuracy and examined in relation to cognitive and biomarker outcomes. Linear regression analysis revealed a significant association between RTACC and changes in Repeatable Battery for the Assessment of Neuropsychological Status scores from baseline to 24 weeks (beta coefficient = -11.90 ± 3.78, T = - 3.14, P = 0.002). RTACC also showed a marginal effect on changes in brain-derived neurotrophic factor levels (beta coefficient = - 3.13 ± 1.64, P = 0.057). Logistic regression analysis demonstrated that RTACC combined with clinical information identified good responders with an area under the receiver operating characteristic curve of 0.73 (95% CI: 0.62-0.84). These findings suggest that this in-game digital biomarker (RTACC) may help identify individuals likely to benefit from multi-domain intervention. Show less

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 H Show less

Stress-related psychiatric disorders are underpinned by dysfunction in the prefrontal cortex and hippocampus; however, the underlying circuit-specific mechanisms remain ill-defined. Here, we identified the basolateral amygdala (BLA)-to-ventral hippocampus (vHPC) circuit as a critical regulator of stress-coping behaviors. Although chronic social defeat stress reduced the mGluR5 expression in both the vHPC and medial prefrontal cortex (mPFC), our circuit-specific behavioral analysis revealed that the activation of the BLA-vHPC circuit produced a significantly greater improvement in coping behavior compared with the activation of the BLA-mPFC circuit. Subsequently, we mechanistically demonstrated that reduced mGluR5 in the vHPC directly impairs CREB-mediated brain-derived neurotrophic factor (BDNF) transcription, a molecular cascade tightly linked to passive coping. These findings reveal a novel circuit-specific molecular mechanism governing stress recovery, positioning the mGluR5-BDNF pathway as a highly specific and promising therapeutic target for future gene therapy interventions. Show less

This study explores the therapeutic potential of hydrogel-encapsulated neurospheres derived from human umbilical cord mesenchymal stem cells (hUC-MSCs) in mitigating traumatic brain injury (TBI) and enhancing functional recovery in a rodent model. Trans-septal (intranasal) transplantation of these neurospheres demonstrated significant neurological improvement, reduced neuronal damage, and preserved neuronal structures and functions. The hUC-MSCs cultured in a customized bioreactor retained essential MSC characteristics, including marker expression and multi-lineage differentiation potential, ensuring their therapeutic efficacy. Following neural induction, hUC-MSCs formed neurospheres that promoted cell aggregation, differentiation, and neuroprotective effects. Encapsulation within a hydrogel provided a stable environment, significantly reducing TBI-induced cell death in co-cultured HT22 cells and improving Show less

Drug chemoresistance remains a major reason of treatment failure in cancer patients. In head and neck squamous cell carcinoma (HNSCC), the seventh most common cancer worldwide, cisplatin chemotherapy remains the gold standard for advanced tumors but often faces loss of responsiveness and the drawback of relapse. We previously showed that the metabolic and angiogenic factor angiopoietin-like 4 (ANGPTL4) is a molecular biomarker of oral dysplasia and HNSCC. We also found that through interaction with Neuropilin 1 (NRP1), ANGPTL4 activates proliferative and migratory pathways that contribute to HNSCC development. Using HNSCC xenografts, patient tumor-derived organoids, tumor spheroids, and HNSCC cell lines, CAL27, HN13, and HN4, here we provide evidence of the role of ANGPTL4 in the development of platinum-based chemoresistance in HNSCC through the promotion of DNA damage response (DDR) and homologous recombination (HR). ANGPTL4 enhanced these mechanisms by promoting phosphorylation of RAD51 recombinase in Tyr Show less

Climate change creates major challenges in livestock industry, making chickens vulnerable to heat stress because they can tolerate a narrow range of temperatures. Heat stress disrupts metabolic and physiological homeostasis, leading to reduced growth, productivity, reproduction, and immune function, thereby threatening the economic viability of poultry farming. This review explores the multifaceted impacts of heat stress on poultry, including physiological responses, production performance, and immune function. Recent advances in transcriptomic and genomic research have shed light on the molecular mechanisms underlying heat stress resilience in poultry. Key genes such as HSP70, HSP90, HSP27, and HSP47 are significantly upregulated under heat stress, playing vital roles in protein folding, preventing aggregation, and protecting cellular integrity. Additionally, genes like SOD and CAT enhance antioxidant defenses, mitigating oxidative damage. Genes such as RB1CC1, BAG3, and TRMT1L regulate apoptosis and oxidative stress, promoting cell survival. In the liver, CCK, DIO3, and ANGPTL4 improve energy homeostasis and reduce metabolism-related heat production, while BMP10 and MYH7 in the heart contribute to cardiac adaptation during thermal stress. Genetic adaptations such as the Naked neck, Frizzle, and Dwarf gene provide intrinsic thermotolerance by reducing feather mass, altering feather structure, and minimizing body size, thereby improving heat dissipation. These genetic traits, combined with transcriptomic insights into heat resilience genes, offer opportunities for developing heat-tolerant chicken breeds. By integrating molecular genetics, transcriptomics, and management strategies, this review highlights the importance of selective breeding programs to enhance poultry thermotolerance. Future research should focus on leveraging indigenous breeds, advanced molecular tools, and nutritional interventions to mitigate the effects of rising global temperatures. Enhancing heat stress resilience in poultry is imperative to ensure sustainable production and global food security in this climate change. Show less

BackgroundIdentifying genetic variants conferring resilience to Alzheimer's disease and related dementia (ADRD) may hold promise for developing therapeutics.ObjectiveTo determine genetic associations with being dementia-free at age 85 (DF85).MethodsWe examined genetic associations, using whole genome sequencing data, with DF85 in three Trans-Omics for Precision Medicine cohorts and the Alzheimer's Disease Sequencing Project Phenotype Harmonization Consortium. We tested common variants individually and aggregation of rare (MAF ≤ 1%) coding and non-coding variants in DF85 participants (n = 3657) against individuals who were not DF85 (n = 20,010). We verified associations using a stricter control set who developed dementia before age 85 (n = 5552).ResultsWe observed an association at Show less

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a chronic liver condition with a rising global incidence, closely linked to metabolic risk factors such as dyslipidemia. Apolipoprotein E-deficient (ApoE Show less

Liver-metabolic stress and apolipoprotein E (APOE) ε4 are implicated in late-life cognitive vulnerability, yet how hepatic-metabolic indices relate to cognition and amyloid burden and whether these associations vary by APOE ε4 allele dose remains unclear. We examined liver-metabolic indices in relation to cognition and amyloid PET SUVR and tested effect modification by APOE ε4. We analyzed baseline data from the Dementia Platform Korea Trial-Ready Registry (DPK-TRR). Primary multivariable analyses used complete cases for outcomes and covariates ( Higher TyG index and AST/ALT ratio were associated with lower MMSE scores (TyG: Routine liver-metabolic indices were associated with cognitive performance, while FIB-4 stage showed effect modification by APOE ε4 in relation to both cognition and amyloid PET SUVR. These findings support heterogeneity in liver-metabolic and genetic contributions to late-life cognitive vulnerability in a dementia trial-ready registry and motivate longitudinal studies to clarify temporal relationships. Show less

Patients with traumatic brain injury (TBI) and Glasgow Coma Scale scores of 13-15 (historically called mild TBI [mTBI]) commonly experience changes in cognitive functioning, including processing speed, memory, and executive functioning. In a prospective sample ( Show less

Epidemiological analyses suggest that the Ɛ4 allele of apolipoprotein E (ApoE) genes may influence the effects of alcohol on cognitive and executive function and dementia risk compared to the Ɛ3 allele. Here, we investigated this question in female rats given that women are more vulnerable than men to the Ɛ4 genotype effects on various diseases. Experiment 1 examined the effects of alcohol drinking on performance in a Barnes maze and an operant strategy set-shifting (OSS) task during abstinence in wildtype (WT) and homozygous ApoE4 knock-in (E4) rats. Experiment 2 repeated the behavioral assessments to assess the effects of heavy alcohol exposure and explored seizure susceptibility in E4 and homozygous ApoE3 knock-in (E3) rats. The experiments revealed that E4 rats drank significantly higher doses of alcohol than did the WT and E3 rats. However, there was no genotype or alcohol effect on performance in the Barnes maze and the OSS task. Notably, E4 rats had a shorter latency to kainate-induced seizures and maintained worse seizures compared to age-matched E3 rats. These findings suggest that the Ɛ4 allele may confer a higher risk for increased alcohol drinking without significantly exacerbating alcohol-associated decline in cognitive and executive function in females. Given the scarcity and discrepant reports regarding the role of ApoE polymorphism on seizure disorders among human and rodent studies, results of this study also underscore the need for more rigorous clinical and preclinical studies to determine the role of ApoE in sporadic and alcohol withdrawal seizures. Show less

Non-alcoholic fatty liver disease and atherosclerosis may share a common pathogenesis involving chronic IL-1β-induced inflammation. We aimed to evaluate the efficacy of diacerein, an IL-1 pathway inhibitor, in improving liver fibrosis, steatosis, and atherosclerosis in apolipoprotein E-knockout (apoE k/o) mice. ApoE k/o mice fed a high-fat diet (HFD) were divided into three groups based on diacerein dosage. Liver fat accumulation and fibrosis severity were compared across groups, along with changes in the expression of genes related to lipid metabolism and fibrosis. Atherosclerotic burden in the aorta was evaluated via en face analysis, and the related signaling pathway was verified in vitro. Diacerein treatment reduced the amount of collagen fibers and fat accumulation in the liver in a dose-dependent manner as well as fibrosis-related gene expression. Atherosclerotic plaque burden in the aorta showed a decreasing trend with diacerein treatment, accompanied by reduced expression of pro-inflammatory cytokines, including TNF-α. Diacerein treatment ameliorated liver steatosis/fibrosis and showed beneficial effects on atherosclerosis-related mechanisms in HFD-fed apoE k/o mice. Given its dual anti-inflammatory and anti-fibrotic actions, diacerein represents a promising therapeutic candidate for metabolic disorders characterized by chronic inflammation. KEY MESSAGES: We analyzed the effects of diacerein on liver fibrosis, steatosis, and atherosclerosis in apolipoprotein E knockout (apoE k/o) mice. Diacerein reduced fat accumulation in the liver and collagen fibers in the liver. It decreased the expression of genes related to fibrosis and the burden of atherosclerotic plaque in the aorta. The expression of pro-inflammatory cytokines was reduced. Treatment of apoE knockout mice fed an HFD with diacerein effectively ameliorated liver steatosis/fibrosis and atherosclerosis. Show less

The APOE-ε4 allele is the strongest genetic risk factor for late-onset Alzheimer's disease. However, APOE-ε4 is not deterministic, highlighting the need to identify additional genetic and environmental factors. APOE-ε4 has been linked to accelerated cognitive decline, so we sought to investigate genetic factors that modify APOE-ε4-associated cognitive decline. We conduct cross-ancestry APOE-ε4-stratified and interaction GWAS using harmonized cognitive data from 32,778 participants, including 29,354 non-Hispanic White and 3,424 non-Hispanic Black individuals. Our primary outcome is late-life cognition, measured using harmonized composite scores for memory, executive function, and language, modeled as continuous traits reflecting both normative cognitive aging and disease-related decline. We identify two genome-wide significant loci in APOE-ε4 carriers, reaching genome-wide significance for executive function. These loci also demonstrate nominal associations across the other domains, suggesting broad effects on cognition. In non-carriers, we identify a genome-wide significant association at ITGB8 restricted to executive function, and another locus associated with language. We further link these loci to SEMA6D, GRIN3A, and ITGB8 through expression and methylation databases. Post-GWAS analyses implicate additional genes including SLCO1A2, and DNAH11. Genetic correlation analyses reveal differences by APOE-ε4 status for immune-related traits, suggesting immune-related predispositions may exacerbate cognitive risk in APOE-ε4 carriers. Show less

BackgroundOthers have examined heterogeneity in Alzheimer's disease (AD); however, few have used longitudinal data while accounting for variation in disease stage. We used latent classes to model heterogeneity in the trajectories of three cognitive domains (memory, language, and executive functioning) starting at AD dementia diagnosis.ObjectiveOur aim was to describe the patterns of heterogeneity in cognitive decline across cognitive domains during the course of AD and to contextualize our findings by assessing associations with demographic factors and neuropathological measures.MethodsWe used cognitive data from the Religious Orders Study, the Rush Memory and Aging Project, and the Minority Aging Research Study in a multi-dimensional joint latent class mixed model, which allowed us to estimate cognitive trajectories that varied across cognitive domains and latent classes. We accounted for the uncertainty in latent class assignment and corrected for multiple hypotheses when assessing the association of the latent classes with demographic and neuropathological variables.ResultsWe identified five latent classes differentiated by level of impairment (high to low) and rate of decline (slow to fast). Within each latent class, the pattern of decline did not differ substantially across cognitive domains. Classes were associated with Show less

Decreasing body mass index (BMI) from midlife to late life has been linked to increased Alzheimer's disease (AD) risk and cognitive decline; however, the association with in vivo AD pathology remains unclear. This study aimed to clarify the relationship between midlife-to-late-life BMI changes and in vivo AD pathologies, specifically amyloid-β (Aβ), tau, and AD-signature region cerebral glucose metabolism (AD-CM). This observational cohort study included non-demented older adults recruited from the Korean Brain Aging Study for Early Diagnosis and Prediction of Alzheimer’s Disease (KBASE) between January 2014 and December 2020. Participants underwent clinical evaluations and positron emission tomography (PET) imaging to measure brain Aβ, tau, and AD-CM. Midlife BMI was retrospectively estimated from self-reported weight at ages 40–50 years, while late-life BMI was measured during the study. Participants were categorized based on BMI changes as decreasing (≤ − 4%), stable (− 4% to < 4%), or increasing (≥ 4%). Associations between BMI patterns and AD pathologies were analyzed using multiple linear regression models. A total of 268 participants (mean age 66.6 ± 7.9 years; 56.3% women; 22.5% APOE ε4 carriers) were analyzed. Higher midlife BMI correlated significantly with lower AD-CM (β = − 0.009; 95% CI, − 0.015 to − 0.003; A decreasing BMI trajectory from midlife to late life is associated with enhanced AD-related neurodegeneration, underscoring the clinical importance of monitoring long-term body weight changes in relation to Alzheimer's disease pathophysiology. The online version contains supplementary material available at 10.1186/s13195-026-01967-z. Show less

"SuperAgers" are oldest-old adults (ages 80+) whose memory performance more closely resembles middle-aged adults. The present study examined apolipoprotein E (APOE) allele frequency in non-Hispanic Black (NHB) and non-Hispanic White (NHW) SuperAgers compared to controls and Alzheimer's disease dementia cases. In 18,080 participants from eight cohorts, harmonized clinical diagnostics and memory, executive function, and language domain scores were used to identify SuperAgers, cases, and controls across age-defined bins. NHW SuperAgers had significantly lower frequency of APOE-ε4 alleles and higher frequency of APOE-ε2 alleles compared to all cases and controls, including oldest-old controls. Similar patterns were found in a small yet substantial sample of NHB SuperAgers; however, not all comparisons with controls reached significance. We demonstrated strong evidence that APOE allele frequency relates to SuperAger status. Further research is needed with a larger sample of NHB SuperAgers to determine if mechanisms conferring cognitive resilience differ across race groups. Apolipoprotein E (APOE) allele frequency differs between SuperAgers and cases APOE allele frequency differs between non-Hispanic White SuperAgers and controls The relationship of APOE and non-Hispanic Black SuperAger status is unclear. Show less

Alzheimer's disease (AD) is marked by amyloid-β (Aβ) accumulation, tau pathology, and neuroinflammation. The β-site APP cleaving enzyme 1 (BACE1) is a key driver of Aβ production, while the NLRP3 inflammasome mediates microglial inflammatory responses. Histone deacetylase 6 (HDAC6), a cytoplasmic deacetylase, is upregulated in AD, yet its role in disease mechanisms remains unclear. Here, we show that HDAC6 promotes BACE1 protein stability through direct deacetylation of its C-terminal lysine (K501), thereby increasing Aβ production. HDAC6 also facilitated NLRP3 inflammasome activation in microglia, increasing IL-1β production in a catalytic domain-dependent manner. HDAC6 deficiency in 5xFAD mice reduced BACE1 accumulation, Aβ deposition, ASC speck formation, and IL-1β levels, accompanied by improved cognitive performance. Transcriptomic profiling further revealed downregulation of disease-associated microglial and neurotoxic astrocyte signatures alongside enrichment of synaptic pathways. These findings establish HDAC6 as a dual regulator of Aβ production and neuroinflammation, highlighting it as a promising therapeutic target in AD. Show less

Aberrant deposition of β-amyloid (Aβ) and hyperphosphorylated tau, along with neuroinflammation, are key drivers of Alzheimer's disease (AD) pathology. Here, we identify ramalin, a natural antioxidant, as a promising therapeutic agent that alleviates AD pathology by modulating β-site APP cleaving enzyme 1 (BACE1), histone deacetylase 6 (HDAC6), and the mitogen-activated protein kinases (MAPK) pathway. Ramalin reduced BACE1 protein levels, independently of its transcription, translation, or enzymatic activity, an effect mediated by inhibition of HDAC6. Consistently, HDAC6 knockout similarly decreased BACE1 levels, highlighting HDAC6 as a key regulator of BACE1. Ramalin further suppressed neuroinflammatory responses by downregulating inducible nitric oxide synthase (iNOS) and the NLR family pyrin domain containing 3 (NLRP3) inflammasome. In AD mouse models, ramalin treatment significantly attenuated neuroinflammation, Aβ plaque burden, and tau hyperphosphorylation, while improving cognitive performance. Notably, ramalin reversed Aβ oligomer-induced synaptic transmission impairment and restored synaptic vesicle recycling in hippocampal neurons. Transcriptomic analysis identified modulation of the MAPK pathway, with reduced phosphorylation of c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) implicated in tau pathology. These findings establish ramalin as a disease-modifying intervention that provides neuroprotection through concurrent regulation of BACE1, HDAC6, and MAPK signaling pathway. Collectively, our findings highlight ramalin as a compelling disease-modifying candidate with the potential to drive a breakthrough approach targeting AD pathology. Show less