Ficus deltoidea attenuates tau hyperphosphorylation and neurodegeneration in a D-galactose and aluminum-induced Alzheimer's disease-like rat model.

Tau phosphorylation homeostasis: Mechanisms, targets, and therapeutic implications in Alzheimer's disease.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive decline, memory loss, and behavioral changes, with no effective treatments currently available. Oxidative stress has been shown to be associated with AD, but the causal relationship of AD by oxidative stress remains unestablished. Activation of the Nrf2 pathway is a powerful way to counteract oxidative stress. There are lines of evidence that the pathological features, including Aβ deposition, Tau phosphorylation, neuroinflammation, and mitochondrial dysfunction, could be ameliorated by different antioxidant measures. A group of Nrf2 pathway activators, functioning as Michael acceptors, can covalently modify the Keap1 protein. Such a reaction triggers a conformational change of Keap1, facilitating the release of functional Nrf2 and its subsequent translocation into the nucleus. As a result, a cascade of antioxidant related proteins is expressed. Many plant-derived compounds with Nrf2 pathway activation properties were shown to improve the AD symptom in animal models. This review summarizes the phytochemicals and FDA-approved drugs with diverse structure, including isothiocyanates, polyphenols, phenylpropanoids, flavonoids, terpenes, and alkaloids, but all with Nrf2 pathway activation function and effects on the ameliorating effects on AD symptoms. Three of FDA-approved drugs, being Nrf2 activators, are for the disorders in nervous system. Therefore, Nrf2 could be a promising target for future drug development based on rational design or on the screening from the phytochemicals.

A unique compound 3c targets GSK-3β and metal ion, interferes with tau and metal dyshomeostasis, promotes neurite outgrowth, decreases Aβ accumulation and ABTS•+, and enhances zebrafish motility.

Targeting STAT3 in Alzheimer's disease: Potential mechanisms and therapeutic implications.

Berberine chloride-loaded polymeric lipid hybrid nanoparticles ameliorate cognitive impairment by reducing phosphorylation of tau at threonine 231.

Alzheimer's disease (AD) is characterized by extracellular β-amyloid (Aβ) deposition and intracellular Tau hyperphosphorylation, yet upstream factors that coordinately regulate both pathologies remain poorly understood. Here, we identify proline-rich transmembrane protein 3 (PRRT3) as a previously unrecognized, neuron-enriched upstream regulator of AD dual pathology. PRRT3 expression is elevated in brain tissues from AD patients and exhibits abnormal persistence in APP/ PS1 mice. PRRT3 knockdown markedly reduces APP, PS1, and BACE1 mRNA expressions, thereby decreasing Aβ generation in neuronal cells. Mechanistically, PRRT3 promotes the expressions of these amyloidogenic genes via activation of the activator protein-1 (AP-1) complex, as evidenced by reduced phosphorylation of c-Fos and c-Jun after PRRT3 knockdown. Transcriptomic profiling further reveals broad downregulation of calcium signaling-related receptors and intracellular calcium-handling proteins, accompanied by attenuated calcium signaling and ERK activity. Artificially elevating intracellular calcium with thapsigargin completely reverses the neuroprotective effects of PRRT3 knockdown, restoring both the Ras-ERK-AP-1-dependent amyloidogenic machinery and CaMKII/PP2A-mediated Tau hyperphosphorylation. In parallel, PRRT3 knockdown shifts the balance between the Ca 2+-dependent Tau kinase CaMKII and the phosphatase PP2A, leading to reduced Tau hyperphosphorylation at multiple AD-relevant sites. Collectively, these findings establish PRRT3 as a neuron-enriched upstream regulator linking calcium dysregulation to both amyloidogenic processing and Tau phosphorylation. Targeting PRRT3 may therefore represent a promising strategy to simultaneously modulate the two core pathological processes in AD.

Stroke survivors face an elevated risk of developing Alzheimer's disease (AD), yet the biological mechanisms linking these conditions remain poorly defined. Here, we show that a stroke-induced gut microbiome is a key driver of AD-related pathology. Fecal microbiota transplantation (FMT) from stroke patients into young triple-transgenic Alzheimer's disease (3xTg-AD) mice accelerated tau phosphorylation, increased neuroinflammation, and disrupted metabolic homeostasis in both the brain and gut, compared with FMT from healthy donors. Mice receiving stroke-derived microbiota exhibited persistent, donor-specific dysbiosis and broad metabolic reprogramming involving redox balance, nucleotide metabolism, and energy pathways in cecal contents and brain tissue. These metabolic disturbances were accompanied by widespread and region-specific transcriptional changes revealed by single-cell spatial transcriptomics, including glial activation, impaired neuron-glia communication, and dysregulation of mitochondrial, amyloid-processing and inflammatory pathways across cortical and hippocampal regions. Collectively, these findings identify post-stroke gut dysbiosis as a mechanistic contributor to heightened neurodegenerative vulnerability and AD risk, highlighting the gut-brain axis as a potentially modifiable target for preventing post-stroke dementia.

Brain endothelial Gαq/11 signalling in cerebrovascular function and cognition of aged mice.

Memory loss is linked to failure of the engram, the physical substrate associated with a specific memory. Tau is a microtubule associated protein best known for its central role in neurodegenerative dementias, yet its physiological function in memory formation remains poorly understood. In this work, we show that tau is crucial for forming long lasting memories in mice. Site-specific tau phosphorylation at threonine-205 (T205) is induced by memory encoding and is required for remote memory formation. Tau T205 phosphorylation regulates engram cell, physical unit of memory storage, recruitment and constrains extraneous local cell activation, thereby promoting efficient memory recall. Tau selectively links sensory cue presentations to the encoding ensemble, as optogenetic retrieval of remote memory is tau-independent. Pathogenic tau within active cell ensembles induces aberrant local activation and causes anterograde or retrograde amnesia when present during an encoding or recall time window, respectively. Together, these findings identify a direct physiological role for tau in engram ensemble regulation and establish a mechanistic link between tau dysfunction and memory loss.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline, memory loss, and neuronal death. Approved therapies, including acetylcholinesterase inhibitors and NMDA receptor antagonists, provide only symptomatic relief without halting progression. AD involves multifaceted pathologies: amyloid-β (Aβ) accumulation, tau hyperphosphorylation, oxidative stress, neuroinflammation, mitochondrial dysfunction, and apoptosis. Multi-target natural compounds like ginsenosides from Panax ginseng show promise in preclinical models by modulating these pathways. Key ginsenosides (Rg1, Rb1, Rc, Rd, Re, Rg3) inhibit Aβ production (via BACE1 suppression and α-secretase enhancement), promote Aβ clearance (via IDE/NEP upregulation), reduce tau phosphorylation (via GSK-3β/CDK5 modulation), and exert antioxidant, anti-inflammatory, and anti-apoptotic effects. Limited clinical evidence from small open-label trials of Korean Red Ginseng suggests cognitive improvements (e.g., in ADAS-cog and MMSE scores), with good tolerability. However, poor oral bioavailability and limited blood-brain barrier (BBB) penetration remain challenges, addressable via intranasal or nanoparticle delivery. While preclinical data are robust, clinical translation is limited by study heterogeneity and small samples. Ginsenosides warrant further investigation as adjunctive multi-target agents for AD.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by extracellular amyloid-β plaque accumulation and intracellular tau neurofibrillary tangles, with tau pathology correlating more closely with cognitive decline. Modulation of tau phosphorylation through the regulation of O-GlcNAcylation, a post-translational modification controlled by O-GlcNAcase (OGA), represents a promising therapeutic strategy. In this study, we report the optimization of a pyrimidine hit identified by high-throughput screening, leading to the discovery and optimization of a novel series of 5-azaindole-based OGA inhibitors. From this series, compound 24 was identified as an in vivo tool candidate that demonstrated a favorable pharmacokinetic profile and measurable brain exposure. Pharmacodynamic studies in murine models demonstrated that compound 24 induced a significant and transient elevation of brain O-GlcNAcylation levels, confirming the in vivo target engagement. These findings underscore the potential of 5-azaindole-based OGA inhibitors as a novel validated chemotype for modulation of O-GlcNAcylation.

Anti-IgLON5 disease is an autoimmune disease, in which autoantibodies (AABs) against the neuronal cell surface protein IgLON5 lead to profound brain dysfunction and Tau pathology. How α-IgLON5 AABs cause neuronal Tau protein pathology and neurodegeneration remains unclear. We find that patient-derived α-IgLON5 AABs cluster IgLON5 proteins with other cell surface proteins, leading to neuronal hyperactivity that triggers pathological Tau missorting and phosphorylation, typically observed early in Tau-related neurodegenerative diseases. In wild-type mice, α-IgLON5 AABs induce hippocampal Tau phosphorylation and neuroinflammatory responses. Our findings establish a causal link between the α-IgLON5 AABs and Tau pathology in anti-IgLON5 disease patients and highlight the role of neuronal hyperactivity as a disease-overarching driver of Tau pathology and provide a potential target for therapeutic intervention.

Neuroinvasion Pathways of Treponema denticola and Its Role in Amyloidogenesis and Neuroinflammation: A Systematic Review.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterised by the accumulation of amyloid-β plaques, tau tangles, and extensive synaptic and neuronal loss. Increasing evidence suggests that the condition develops through the combined effects of protein misfolding, lipid dysregulation, oxidative stress, and chronic neuroinflammation. Among these processes, the APOE ε4 allele has a central role by linking disrupted lipid metabolism to impaired amyloid clearance, abnormal tau phosphorylation, and heightened neuronal vulnerability. This relationship highlights lipidopathy as a potential upstream driver of disease progression rather than a secondary feature. Advances in biomarker research, including cerebrospinal fluid and plasma assays, molecular imaging, and microRNA profiles, now enable detection of AD pathology years before clinical symptoms become evident and allow patient stratification based on molecular signatures. Despite these advances, currently available symptomatic and disease-modifying therapies remain limited in their ability to halt or reverse cognitive decline. This review synthesises recent findings across amyloid, tau, and lipid-driven mechanisms, while providing a comparative analysis of therapeutic strategies and their limitations. A lipid-focused, multi-target framework is proposed in which correcting metabolic imbalance enhances the effectiveness of amyloid- and tau-directed interventions. Such an approach may strengthen precision medicine and offer a realistic path toward improved outcomes in AD.

The emerging role of polo-like kinase 2 in Alzheimer's disease.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder which results in cognitive decline and memory loss, characterized by the accumulation of amyloid beta (Aβ) plaques and neurofibrillary tangles in the brain. Despite numerous efforts to develop animal models of AD across various species to understand its pathological characteristics and underlying mechanisms, the model that accurately mimics the pathological phenotypes of AD remains elusive. In this study, we aimed to induce sporadic AD pathological progression in non-human primates (NHP) through the repeated administration of Aβ oligomers (AβO) via the CBCT-guided intra-cisterna manga (ICM) injection. Cynomolgus monkeys were administered AβO twice a week for four weeks, and then euthanized one week after the final injection. We found that AβO-injected NHP developed AD pathologies, including Aβ deposition, synaptic impairment, and neuroinflammation in the CA1 area of the hippocampus. Additionally, the levels of hyperphosphorylated tau were significantly increased in the cerebrospinal fluid (CSF) of AβO-injected NHP. Our results demonstrate that repeated AβO injection via the ICM route induces several early-stage AD-like neuropathological alterations, including intracellular Aβ accumulation, tau phosphorylation, and synaptic dysfunction. The present study indicates that repeated ICM administration of AβO could be good approach to reproduce a translational NHP model of AD, enabling the study of AD pathogenesis and pre-clinical testing of potential therapeutic candidates for AD.

Tauopathies arise when normal functions of the tau protein in axonal transport and neuronal maintenance are disrupted by an imbalance between kinases and phosphatases. Dysregulation of key kinases such as dual-specificity Tyrosine-Regulated Kinase 1A (DYRK1A), Tau Tubulin Kinase 1 (TTBK1), and ABL Proto-Oncogene 1, and Non-Receptor Tyrosine Kinase (ABL1) drives excessive tau phosphorylation and neurofibrillary tangle accumulation. DYRK1A regulates MAPT exon 10 splicing and phosphorylates tau at multiple Ser/Thr residues, priming it for further phosphorylation by other kinases. TTBK1 phosphorylates tau at disease-associated epitopes within the microtubule-binding domain, promoting detachment from microtubules and aggregation. ABL1 phosphorylates tau at tyrosine residues, linking tau modification with Aβ-induced synaptic dysfunction. These events collectively drive tau hyperphosphorylation, misfolding, and neurofibrillary pathology characteristic of tauopathies. To identify natural product-derived multitarget inhibitors for these kinases, we developed a comprehensive machine learning (ML) workflow trained on bioactivity data from ChEMBL and BindingDB. We implemented five distinct classifiers: CatBoost, Support Vector Machine (SVM), k-Nearest Neighbors (KNN), Naive Bayes, and XGBoost. Stratified sampling and SMOTE were employed to address class imbalance for DYRK1A and ABL1, while Bemis-Murcko scaffold splitting was used to ensure rigorous evaluation of the data-scarce TTBK1 data set. A soft-voting ensemble model, integrating optimized CatBoost, XGBoost, and SVM, demonstrated superior performance. This robust ensemble was deployed to screen ∼695,000 natural compounds from the COCONUT 2.0 database. The resulting hits were refined through consensus molecular docking and deep learning-based rescoring (GNINA), leading to the identification of two high-potential lead molecules, CNP0591834.1 and CNP0484145.0. Validation using 1 μs molecular dynamics simulations confirmed their conformational stability and strong binding affinities. Steered MD further demonstrated their superior mechanical resistance to unbinding, particularly in DYRK1A and ABL1 complexes. Overall, this integrative computational framework highlights these two natural compounds as potent multitarget leads with strong potential to mitigate tau-hyperphosphorylation-driven neurodegeneration.

Alzheimer's disease (AD) is a multifactorial disease with mixed pathologies. Consequentially, drugs targeting multiple pathological processes may offer synergistic benefits. While histone deacetylase (HDAC) inhibitors have demonstrated efficacy in alleviating AD-related pathologies in animal models, the neuroprotective Wnt/β-catenin signaling pathway remains compromised in AD brain. CI-994 is a class I HDAC inhibitor containing N-(2-aminophenyl)-benzamide. Our recent studies indicate that CI-994 is also an activator of Wnt/β-catenin signaling by stabilizing Wnt co-receptor LRP6. We herein use CI-994 as a scaffold to develop novel potent dual modulators of class I HDACs and Wnt/β-catenin signaling for AD therapy. Our lead compound, W2A-28, selectively inhibits class I HDAC1, 2 and 3 with IC 50 values of 0.51 μM, 0.68 μM, and 0.22 μM, respectively, and shows no inhibitory activities on other HDACs. Furthermore, W2A-28 potently activates Wnt reporter activity with an EC 50 value of 1.61 μM in Wnt-3A-expressing HEK293 cells. As expected, activation of Wnt/β-catenin signaling by W2A-28 is associated with elevated LRP6 protein level. Importantly, W2A-28 displays excellent microsomal stability in both mouse and human liver microsomal stability assays, alongside high permeability and a lack of active efflux in MDR1-MDCKII models. Critically, W2A-28 treatment significantly enhances histone acetylation, activates Wnt/β-catenin signaling, and suppresses tau phosphorylation in AD patient-specific cerebral organoids carrying APOE ε4/ε4 or APOE ε3/ε4 with PSEN1 M146V mutation. Our findings position W2A-28 as a promising multi-target drug candidate for AD therapy.

Alzheimer's disease (AD) is characterized by impaired spatial learning functions, amyloid-β accumulation, tau hyperphosphorylation, and neuroinflammation. Antiepileptic drugs such as lamotrigine have shown promise in improving brain functions in AD, but the underlying mechanisms remain unclear. This study aimed to evaluate the therapeutic effects of lamotrigine in amyloid precursor protein/presenilin 1 (APP/PS1) transgenic mice and elucidate the underlying molecular mechanisms using integrated transcriptomic and metabolomic analyses. APP/PS1 mice were treated with lamotrigine from 3 months of age, and spatial learning performance was assessed using the Morris water maze test. Histological and molecular changes were evaluated through hematoxylin and eosin staining, Western blotting, ELISA, and immunohistochemistry. High-throughput RNA sequencing and untargeted metabolomics were performed to explore differentially expressed genes, metabolites, and enriched signaling pathways. Western blot validation and pharmacological inhibition were used to verify pathway involvement. Lamotrigine treatment significantly improved spatial learning performance, ameliorated neuronal degeneration, and decreased Aβ1 levels and tau phosphorylation in the brains of APP/PS1 mice. Inflammatory markers and glial activation were also markedly suppressed. Multi-omics analysis revealed alterations in key pathways related to synaptic plasticity, lipid metabolism, and autophagy. Notably, both omics data and protein validation highlighted the cAMP/PKA/CREB pathway as a potentially relevant pathway. Co-administration of the PKA inhibitor H89 abolished lamotrigine-induced upregulation of p-CREB and BDNF, supporting the involvement of this pathway. Lamotrigine improves spatial learning and attenuates AD-related pathology in APP/PS1 mice, possibly through modulation of the cAMP/PKA/CREB signaling pathway, highlighting its potential as a candidate for further investigation.