(-)-Epigallocatechin-3-Gallate Diminishes Intra-and Extracellular Amyloid-Induced Cytotoxic Effects on Cholinergic-like Neurons from Familial Alzheimer's Disease PSEN1 E280A

Minocycline mitigates Aβ and TAU pathology, neuronal dysfunction, and death in the PSEN1 E280A cholinergic-like neurons model of familial Alzheimer's disease

Familial Alzheimer's disease (FAD) presenilin 1 E280A (PSEN1 E280A) is a severe neurological condition due to the loss of cholinergic neurons (ChNs), accumulation of amyloid beta (Aβ), and abnormal phosphorylation of the TAU protein. Up to date, there are no effective therapies available. The need for innovative treatments for this illness is critical. We found that minocycline (MC, 5 μM) was innocuous toward wild-type (WT) PSEN1 ChLNs but significantly (i) reduces the accumulation of intracellular Aβ by -69%, (ii) blocks both abnormal phosphorylation of the protein TAU at residue Ser202/Thr205 by -33% and (iii) phosphorylation of the proapoptotic transcription factor c-JUN at residue Ser63/Ser73 by -25%, (iv) diminishes oxidized DJ-1 at Cys106-SO3 by -29%, (v) downregulates the expression of transcription factor TP53, (vi) BH-3-only protein PUMA, and (vii) cleaved caspase 3 (CC3) by -33, -86, and -78%, respectively, compared with untreated PSEN1 E280A ChLNs. Additionally, MC increases the response to ACh-induced Ca2+ influx by +92% in mutant ChLNs. Oxygen radical absorbance capacity (ORAC) and ferric ion-reducing antioxidant power (FRAP) analysis showed that MC might operate more efficiently as a hydrogen atom transfer agent than a single electron transfer agent. In silico molecular docking analysis predicts that MC binds with high affinity to Aβ (Vina Score -6.6 kcal/mol), TAU (VS -6.5 kcal/mol), and caspase 3 (VS -7.1 kcal/mol). Taken together, our findings suggest that MC demonstrates antioxidant, anti-amyloid, and anti-apoptosis activity and promotes physiological ACh-induced Ca2+ influx in PSEN1 E280A ChLNs. The MC has therapeutic potential for treating early-onset FAD.

Olive Oil Industry By-Products as a Novel Source of Biophenols with a Promising Role in Alzheimer Disease Prevention

This review explores the potential health benefits and applications of phenolic secoiridoids derived from olive oil by-products in the prevention of Alzheimer's disease (AD). As reviewed herein, polyphenols, such as epigallocatechin-3-gallate, epicatechin, and resveratrol, show in vitro and in vivo antioxidant, anti-inflammatory, and neuroprotective properties, and are particularly relevant in the context of AD, a leading cause of dementia globally. The olive oil industry, particularly in the Mediterranean region, produces significant amounts of waste, including leaves, pomace, and wastewater, which pose environmental challenges but also offer an untapped source of bioactive compounds. Despite promising in vitro and in vivo studies indicating that olive-derived polyphenols, such as oleuropein and hydroxytyrosol, may mitigate AD pathology, human clinical trials remain limited. The variability in extraction methods and the complex nature of AD further complicate research. Future studies should focus on standardizing the protocols and conducting robust clinical trials to fully assess the therapeutic potential of these compounds. This approach not only supports the development of new treatments for AD but also promotes environmental sustainability by valorizing olive oil industry waste.

Trends and hotspots in tea and Alzheimer's disease research from 2014 to 2023: A bibliometric and visual analysis

Objectives

The positive effects of tea on Alzheimer's disease (AD) have increasingly captured researchers' attention. Nevertheless, the quantitative comprehensive analysis in the relevant literatur is lack. This paper aims to thoroughly examine the current research status and hotspots from 2014 to 2023, providing a valuable reference for subsequent research.

Methods

Documents spanning from 2014 to 2023 were searched from the Web of Science, and the R software, VOSviewer, and Citespace software were used for analysis and visualization.

Results

A total of 374 documents were contained in the study. The rate of article publications exhibited a consistent increase each year from 2014 to 2023. Notably, China emerged as the leading country in terms of published articles, followed by the United States and India. Simultaneously, China is also in a leading position in cooperation with other countries. Molecules emerged as the most frequently published journal, while the Journal of Alzheimer's Disease secured the top spot in terms of citations. The identified main keywords included oxidative stress, amyloid, epigallocatechin gallate, and green tea polyphenol, among others. These focal areas delved into the antioxidative and anti-amyloid aggregation actions of tea's polyphenolic components. Furthermore, the particularly way in which epigallocatechin gallate delivers neuroprotective outcomes by influencing molecules related to AD represents a focal point of research.

Conclusion

The increasing attention from researchers on the role of tea in ameliorating AD positions it as a hot spot in the development of anti-AD drugs in the development of future. Through our generalized analysis of the current landscape and hotspots regarding tea's application in AD, this study provides an estimable reference for future research endeavors.

Development of dietary small molecules as multi-targeting treatment strategies for Alzheimer's disease

Cognitive dysfunction can occur both in normal aging and age-related neurological disorders, such as mild cognitive impairment and Alzheimer's disease (AD). These disorders have few treatment options due to side effects and limited efficacy. New approaches to slow cognitive decline are urgently needed. Dietary interventions (nutraceuticals) have received considerable attention because they exhibit strong neuroprotective properties and may help prevent or minimize AD symptoms. Biological aging is driven by a series of interrelated mechanisms, including oxidative stress, neuroinflammation, neuronal apoptosis, and autophagy, which function through various signaling pathways. Recent clinical and preclinical studies have shown that dietary small molecules derived from natural sources, including flavonoids, carotenoids, and polyphenolic acids, can modulate oxidative damage, cognitive impairments, mitochondrial dysfunction, neuroinflammation, neuronal apoptosis, autophagy dysregulation, and gut microbiota dysbiosis. This paper reviews research on different dietary small molecules and their bioactive constituents in the treatment of AD. Additionally, the chemical structure, effective dose, and specific molecular mechanisms of action are comprehensively explored. This paper also discusses the advantages of using nanotechnology-based drug delivery, which significantly enhances oral bioavailability, safety, and therapeutic effect, and lowers the risk of adverse effects. These agents have considerable potential as novel and safe therapeutic agents that can prevent and combat age-related AD.

Neuroprotective Effect of Combined Treatment with Epigallocatechin 3-Gallate and Melatonin on Familial Alzheimer's Disease PSEN1 E280A Cerebral Spheroids Derived from Menstrual Mesenchymal Stromal Cells

Background

Familial Alzheimer's disease (FAD) is caused by mutations in one or more of 3 genes known as AβPP, PSEN1, and PSEN2. There are currently no effective therapies for FAD. Hence, novel therapeutics are needed.

Objective

To analyze the effect of treatment with a combination of epigallocatechin-3-gallate (EGCG) and Melatonin (N-acetyl-5-methoxytryptamine, aMT) in a cerebral spheroid (CS) 3D in vitro model of PSEN 1 E280A FAD.

Methods

We developed a CS in vitro model based on menstrual stromal cells derived from wild-type (WT) and mutant PSEN1 E280A menstrual blood cultured in Fast-N-Spheres V2 medium.

Results

Beta-tubulin III, choline acetyltransferase, and GFAP in both WT and mutant CSs spontaneously expressed neuronal and astroglia markers when grown in Fast-N-Spheres V2 medium for 4 or 11 days. Mutant PSEN1 CSs had significantly increased levels of intracellular AβPP fragment peptides and concomitant appearance of oxidized DJ-1 as early as 4 days, and phosphorylated tau, decreased ΔΨm, and increased caspase-3 activity were observed on Day 11. Moreover, mutant CSs were unresponsive to acetylcholine. Treatment with a combination of EGCG and aMT decreased the levels of all typical pathological markers of FAD more efficiently than did EGCG or aMT alone, but aMT failed to restore Ca2+ influx in mutant CSs and decreased the beneficial effect of EGCG on Ca2+ influx in mutant CSs.

Conclusion

Treatment with a combination of EGCG and aMT can be of high therapeutic value due to the high antioxidant capacity and anti-amyloidogenic effect of both compounds.

Cholinergic-like neurons and cerebral spheroids bearing the PSEN1 p.Ile416Thr variant mirror Alzheimer's disease neuropathology

Familial Alzheimer's disease (FAD) is a complex neurodegenerative disorder for which there are no therapeutics to date. Several mutations in presenilin 1 (PSEN 1), which is the catalytic component of γ-secretase complex, are causal of FAD. Recently, the p.Ile416Thr (I416T) PSEN 1 mutation has been reported in large kindred in Colombia. However, cell and molecular information from I416T mutation is scarce. Here, we demonstrate that menstrual stromal cells (MenSCs)-derived planar (2D) PSEN 1 I416T cholinergic-like cells (ChLNS) and (3D) cerebral spheroids (CSs) reproduce the typical neuropathological markers of FAD in 4 post-transdifferentiating or 11 days of transdifferentiating, respectively. The models produce intracellular aggregation of APPβ fragments (at day 4 and 11) and phosphorylated protein TAU at residue Ser202/Thr205 (at day 11) suggesting that iAPPβ fragments precede p-TAU. Mutant ChLNs and CSs displayed DJ-1 Cys106-SO3 (sulfonic acid), failure of mitochondria membrane potential (ΔΨm), and activation of transcription factor c-JUN and p53, expression of pro-apoptotic protein PUMA, and activation of executer protein caspase 3 (CASP3), all markers of cell death by apoptosis. Moreover, we found that both mutant ChLNs and CSs produced high amounts of extracellular eAβ42. The I416T ChLNs and CSs were irresponsive to acetylcholine induced Ca2+ influx compared to WT. The I416T PSEN 1 mutation might work as dominant-negative PSEN1 mutation. These findings might help to understanding the recurring failures of clinical trials of anti-eAβ42, and support the view that FAD is triggered by the accumulation of other intracellular AβPP metabolites, rather than eAβ42.

Cannabidiol Protects Dopaminergic-like Neurons against Paraquat- and Maneb-Induced Cell Death through Safeguarding DJ-1CYS106 and Caspase 3 Independently of Cannabinoid Receptors: Relevance in Parkinson's Disease

Parkinson's disease (PD), a progressive neurodegenerative movement disorder, has reached pandemic status worldwide. This neurologic disorder is caused primarily by the specific deterioration of dopaminergic (DAergic) neurons in the substantia nigra pars compacta (SNc). Unfortunately, there are no therapeutic agents that slow or delay the disease progression. Herein, menstrual stromal cell-derived dopamine-like neurons (DALNs) intoxicated with paraquat (PQ²⁺)/maneb (MB) were used as a model system to elucidate the mechanism by which CBD protects the neural cell from apoptosis in vitro. According to immunofluorescence microscopy, flow cytometry, cell-free assay, and molecular docking analysis, we demonstrate that CBD offers protection to DALNs against PQ²⁺ (1 mM)/MB (50 μM)-induced oxidative stress (OS) by simultaneously (i) decreasing reactive oxygen species (ROS: O₂^•-, H₂O₂), (ii) maintaining the mitochondrial membrane potential (ΔΨ_m), (iii) directly binding to stress sensor protein DJ-1, thereby blunting its oxidation from DJ-1CYS¹⁰⁶-SH into DJ-1CYS¹⁰⁶-SO₃, and (iv) directly binding to pro-apoptotic protease protein caspase 3 (CASP3), thereby disengaging neuronal dismantling. Furthermore, the protective effect of CBD on DJ-1 and CASP3 was independent of CB1 and CB2 receptor signaling. CBD also re-established the Ca²⁺ influx in DALNs as a response to dopamine (DA) stimuli under PQ²⁺/MB exposure. Because of its powerful antioxidant and antiapoptotic effects, CBD offers potential therapeutic utility in the treatment of PD.

(-)-Epigallocatechin-3-gallate, a Polyphenol from Green Tea, Regulates the Liquid-Liquid Phase Separation of Alzheimer's-Related Protein Tau

The microtubule-associated protein tau is involved in Alzheimer's disease and other tauopathies. Recently, tau has been shown to undergo liquid-liquid phase separation (LLPS), which is implicated in the physiological function and pathological aggregation of tau. In this report, we demonstrate that the green tea polyphenol (-)-epigallocatechin-3-gallate (EGCG) promotes the formation of liquid tau droplets at neutral pH by creating a network of hydrophobic interactions and hydrogen bonds, mainly with the proline-rich domain of tau. We further show that EGCG oxidation, tau phosphorylation, and the chemical structure of the polyphenol influence the efficacy of EGCG in facilitating tau LLPS. Complementary to the inhibitory activity of EGCG in tau fibrillization, our findings provide novel insights into the biological activity of EGCG and offer new clues for future studies on the molecular mechanism by which EGCG alleviates neurodegenerative diseases.

BH3-Only Proteins Noxa and Puma Are Key Regulators of Induced Apoptosis

Apoptosis is an evolutionarily conserved and tightly regulated cell death pathway. Physiological cell death is important for maintaining homeostasis and optimal biological conditions by continuous elimination of undesired or superfluous cells. The BH3-only pro-apoptotic members are strong inducers of apoptosis. The pro-apoptotic BH3-only protein Noxa activates multiple death pathways by inhibiting the anti-apoptotic Bcl-2 family protein, Mcl-1, and other protein members leading to Bax and Bak activation and MOMP. On the other hand, Puma is induced by p53-dependent and p53-independent apoptotic stimuli in several cancer cell lines. Moreover, this protein is involved in several physiological and pathological processes, such as immunity, cancer, and neurodegenerative diseases. Future heat shock research could disclose the effect of hyperthermia on both Noxa and BH3-only proteins. This suggests post-transcriptional mechanisms controlling the translation of both Puma and Noxa mRNA in heat-shocked cells. This study was also the chance to recapitulate the different reactional mechanisms investigated for caspases.