Against Alzheimer's Disease Research Articles

The Icelandic mutation (APP-A673T) is protective against amyloid pathology in vivo.

A previous epidemiological study in Northern Europe showed that the A673T mutation (Icelandic mutation) in the amyloid precursor protein gene (APP) can protect against Alzheimer's disease (AD). While the effect of the A673T mutation on APP processing has been investigated primarily in vitro, its in vivo impact has not been evaluated. This is mainly because most existing AD mouse models carry the Swedish mutation. The Swedish and Icelandic mutations are both located near the β-cleavage site, and each mutation is presumed to have the opposite effect on β-cleavage. Therefore, in the AD mouse models with the Swedish mutation, its effects could compete with the effects of the Icelandic mutation. Here, we introduced the A673T mutation into App knock-in mice devoid of the Swedish mutation (AppG-F mice) to avoid potential deleterious effects of the Swedish mutation and generated AppG-F-A673T mice. APP-A673T significantly downregulated β-cleavage and attenuated the production of Aβ and amyloid pathology in the brains of these animals. The Icelandic mutation also reduced neuroinflammation and neuritic alterations. Both sexes were studied. This is the first successful demonstration of the protective effect of the Icelandic mutation on amyloid pathology in vivo. Our findings indicate that specific inhibition of the APP-BACE1 interaction could be a promising therapeutic approach. Alternatively, introduction of the disease-protective mutation such as APP-A673T using in vivo genome editing technology could be a novel treatment for individuals at high risk for AD, such as familial AD gene mutation carriers and APOE ε4 carriers.Significance statement The A673T mutation (Icelandic mutation) in the APP gene can protect against AD. The effect of the A673T mutation on amyloid pathology has not been evaluated in vivo. Utilizing a new AD mouse model that we have recently developed, we show that the APP-A673T attenuates amyloid pathology in vivo. We demonstrate that its protective effects are exerted by inhibiting β-cleavage and reducing the production of Aβ in the brain. Furthermore, we reveal that the Icelandic mutation also reduced neuroinflammation and neuritic alterations. Our findings indicate that specific inhibition of the APP-BACE1 interaction or introduction of protective variants via in vivo genome editing could be a promising therapeutic approach.

Alzheimer’s disease-associated protective variant Plcg2-P522R modulates peripheral macrophage function in a sex-dimorphic manner

Genome-wide association studies have identified a protective mutation in the phospholipase C gamma 2 (PLCG2) gene which confers protection against Alzheimer’s disease (AD)-associated cognitive decline. Therefore, PLCG2, which is primarily expressed in immune cells, has become a target of interest for potential therapeutic intervention. The protective allele, known as P522R, has been shown to be hyper-morphic in microglia, increasing phagocytosis of amyloid-beta (Aβ), and increasing the release of inflammatory cytokines. However, the effect of this protective mutation on peripheral tissue-resident macrophages, and the extent to which sex modifies this effect, has yet to be assessed. Herein, we show that peripheral macrophages carrying the P522R mutation do indeed show functional differences compared to their wild-type (WT) counterparts, however, these alterations occur in a sex-dependent manner. In macrophages from females, the P522R mutation increases lysosomal protease activity, cytokine secretion, and gene expression associated with cytokine secretion and apoptosis. In contrast, in macrophages from males, the mutation causes decreased phagocytosis and lysosomal protease activity, modest increases in cytokine secretion, and induction of gene expression associated with negative regulation of the immune response. Taken together, these results suggest that the mutation may be conferring different effects dependent on sex and cell type, and highlight the importance of considering sex as a biological variable when assessing the effects of genetic variants and implications for potential immune system-targeted therapies.

Associations of semaglutide with first-time diagnosis of Alzheimer's disease in patients with type 2 diabetes: Target trial emulation using nationwide real-world data in the US.

Emerging preclinical evidence suggests that semaglutide, a glucagon-like peptide receptor agonist (GLP-1RA) for type 2 diabetes mellitus (T2DM) and obesity, protects against neurodegeneration and neuroinflammation. However, real-world evidence for its ability to protect against Alzheimer's disease (AD) is lacking. We conducted emulation target trials based on a nationwide database of electronic health records (EHRs) of 116 million US patients. Seven target trials were emulated among 1,094,761 eligible patients with T2DM who had no prior AD diagnosis by comparing semaglutide with seven other antidiabetic medications. First-ever diagnosis of AD occurred within a 3-year follow-up period and was examined using Cox proportional hazards and Kaplan-Meier survival analyses. Semaglutide was associated with significantly reduced risk for first-time AD diagnosis, most strongly compared with insulin (hazard ratio [HR], 0.33 [95% CI: 0.21 to 0.51]) and most weakly compared with other GLP-1RAs (HR, 0.59 [95% CI: 0.37 to 0.95]). Similar results were seen across obesity status, gender, and age groups. These findings support further studies to assess semaglutide's potential in preventing AD. Semaglutide was associated with 40% to 70% reduced risks of first-time AD diagnosis in T2DM patients compared to other antidiabetic medications, including other GLP-1RAs. Semaglutide was associated with significantly lower AD-related medication prescriptions. Similar reductions were seen across obesity status, gender, and age groups. Our findings provide real-world evidence supporting the potential clinical benefits of semaglutide in mitigating AD initiation and development in patients with T2DM. These findings support further clinical trials to assess semaglutide's potential in delaying or preventing AD.

Alzheimer's Disease and (Phyto) Estrogen Treatment: Modification of Effects by Age, Type of Treatment, and Duration of Use.

There is a continued debate on whether menopausal hormone therapy (MHT) protects women against Alzheimer's disease (AD). It is also unclear whether phytoestrogen could be an alternative treatment for AD. To investigate whether mixed study findings may be due to differences in age at initiation of MHT and duration of prescription of different types of MHT using meta-analyses. After a systematic literature search, meta-analyses were carried out using Cochrane Revman 5.4.1.software including data from large nationwide studies of registered medically diagnosed AD and prescribed MHT. These analyses were stratified for duration and type of treatment, by age at start of prescription of therapy. Insufficient quality data were available for phytoestrogen treatment and AD meta-analyses. A total of 912,157 women were included from five registries, of whom 278,495 had developed AD during follow-up. Meta-analyses suggested a small increased AD risk after 5-10 years prescription of combination MHT regardless of age, and over 10 years only in women younger than 60 years of age. No association was seen for estrogen alone for women younger than 60 years of age, but AD risk did increase for women over 60 years of age for up to 5 years of MHT prescriptions. Combination MHT should probably be prescribed for less than 5 years after menopause to reduce risk for AD, while estrogen alone should not be prescribed to women over 60. For phytoestrogen, small treatment trials suggested some benefit of tempeh (fermented soy), which should be investigated further.

Formulation and optimization of fisetin nanoemulsion for the treatment of Alzheimer's disease in rats: Pharmacokinetic and pharmacodynamic assessment

Fiestin (FS) is a polyphenolic flavonoid that possesses various neuroprotective effects by attenuating the levels of AChE enzyme, accumulated amyloid β, free radicals and neuroinflammation against Alzheimer's disease (AD). It is also helpful in reducing cellular senescence. However, FS suffers from a dissolution rate-limited oral bioavailability, and poor blood-brain barrier (BBB) permeability leading to decreased therapeutic efficacy. To address these challenges, an attempt has been made to formulate a nanoemulsion (NE) of FS using Box-Behnken design (BBD) as optimization tool. The optimized NE contained 10 mg of FS, 164 μL of Capmul MCM EP/NF® (oil), 618 μL of T80 (surfactant), 218 μL of Transcutol P®, (co-surfactant) and 4000 μL of distilled water. The optimized formulation resulted in a mean droplet size, drug loading, polydispersity index (PDI), and zeta potential (ZP) of 32 nm, 95.5 %, 0.26, and −15.99 mV, respectively. In the pharmacokinetic studies, FS-NE showed 9.2-fold increase in Cmax as compared to naïve FS. Relative oral bioavailability FS loaded in FS-NE was 842.93 %. Further the concentration of FS loaded in FS-NE was 8.81-fold higher in brain than naive FS. To evaluate pharmacodynamic effects, an aluminum chloride (AlCl3)-induced AD rat model was used. Cognitive functions were assessed using the Morris water maze and open field tests. The formulation showed dose-dependent effects. Rats treated with both, low and high doses of FS-NE (groups VI and VII) showed significant improvements (P < 0.001) in cognitive functions in AD-induced rats. The biochemical studies showed that FS-NE at both doses attenuated the levels of AChE enzyme, amyloid β, oxidative stress, and neuroinflammation. Results of histopathology indicated that FS-NE attenuated the degeneration of neurons in the cerebral cortex and hippocampus parts of the brain.

An 11-mer Synthetic Peptide Suppressing Aggregation of Aβ25-35 and Resolving Its Aggregated Form Improves Test Performance in an Aβ25-35-Induced Alzheimer's Mouse Model.

There is a high demand for the development of drugs against Alzheimer's disease (AD), which is related to the misfolding and aggregation of Amyloid-β (Aβ), due to the increasing number of patients with AD. In our present study, we aimed to assess the aggregation inhibitory effect of various synthetic YS-peptides on Aβ25-35 to identify an applicable peptide for clinical use for AD treatment and prevention. Suppression and aggregate resolution activities of YS-peptides against Aβ25-35 were evaluated using a Thioflavin T assay and scanning electron microscopy (SEM). Structure-activity relationship studies revealed that YS-RD11 (RETLVYLTHLD) and YS-RE16 (RETLVYLTHLDYDDTE) showed suppression and aggregate-resolution activities. The effect of YS-peptides on phagocytosis in microglial cells (BV-2 cells) demonstrated that YS-RD11 and YS-RE16 activated the phagocytic ability of microglia. In the Aβ25-35-induced AD mouse model, YS-RD11 prevented and improved the deficits in short-term memory. In conclusion, YS-RD11 is a suitable candidate therapeutic drug against AD and uses a strategy similar to that used for antibodies.

Unlocking the in vitro neuroprotection of sloe residues phenolic extracts by bioanalytical and chemometric strategies

Wild fruits, particularly the underutilized sloe (Prunus spinosa), are gaining interest as natural antioxidants, with residues from liqueur production being a source of bioactive compounds. This study proposes a sustainable approach for valorizing sloe residues, seeds and skins, by employing an innovative green extraction method. HPLC-ESI-QTOF and spectrophotometric techniques were used to explore the phenolic profile, highlighting the predominance of quercetin, 2,3-dihydroxybenzoic and ferulic acids (9.7–57 μg·g−1). In addition, the presence of Cu, Zn and Ca was confirmed by atomic absorption spectroscopy. Simultaneously, their neuroprotective potential against Alzheimer's disease (AD) was studied by exploring the inhibition of beta-amyloid aggregation and oxidative stress cytoprotection in SH-SY5Y cell line, standing out 1 μg·g−1 and 10 μg·g−1 extracts of sloe skin. Phenolic composition was correlated with bioactivities by means of multivariate analysis. These results contributed to highlight the potential of this bio-residue as a neuroprotective agent against AD in pharmaceutical and nutraceutical industries.

Design, Synthesis, and Invitro Pharmacological Evaluation of Novel Resveratrol Surrogate Molecules against Alzheimer's Disease.

A series of resveratrol surrogate molecules were designed, synthesized and biologically evaluated for inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) along with anti-oxidant activity as potential novel multifunctional agents against Alzheimer's disease (AD). Six novel compounds were synthesized by reacting (E)-4-(3,5-Dimethoxystyryl) aniline with benzaldehyde and some selected derivatives of benzaldehyde in the presence of ethanol and a few drops of glacial acetic acid which followed the general scheme involved in the formation of Schiff bases. The spectral analysis data including FT-IR, 1H-NMR, 13C-NMR, and Mass spectroscopy results were found to be in good agreement with the newly synthesized compounds (Resveratrol Surrogate Molecules 1-6). The synthesized compounds were evaluated for their dual cholinesterase inhibitory activities, cytotoxic effect, and anti-oxidant potential. The results showed that compound RSM5 showed potent inhibitory activity against AChE and BChE. In, addition the cytotoxicity of the compound RSM5 is less and found to be within the desirable limit indicating the potential safety of RSM5. Also, it possesses substantial anti-oxidant activity which qualifies RSM5 as an anti-AD agent. Taken together, these findings demonstrate that the molecule RSM5 had the most multifunctional properties and could be a promising lead molecule for the future development of drugs for Alzheimer's treatments.

Development of Epigallocatechin and Ascorbic Acid Dual Delivery Transferosomes for Managing Alzheimer's Disease: In Vitro and in Vivo Studies.

Epigallocatechin-3-gallate (EGCG) and ascorbic acid (AA)-loaded transferosomes (TRANS) were developed for brain delivery. The investigation covered EGCG-TRANS, AA-TRANS, and EGCG-AA-TRANS formulations using the film hydration technique. We analyzed the formed transferosomes to confirm the presence of vesicles loaded with the respective drugs and their performance within a living organism. The sizes of the particles for EGCG-TRANS, AA-TRANS, and EGCG-AA-TRANS were measured correspondingly at 174.2 ± 1.80, 132.7 ± 12.22, and 184.31 ± 9.5 nm. The appearance of diffused rings in the scanning electron microscopic image suggests that the payload has a crystalline structure. The atomic force microscope image displayed minimal surface irregularities, potentially indicating the presence of a lipid layer on the surface. Hemolysis results indicated the safety of the vesicles. The results showed 10.23, 7.21, and 8.20% of hemolysis for EGCG-TRANS, AA-TRANS, and EGCG-AA-TRANS, respectively. In the case of EGCG-AA-TRANS, the release of EGCG was determined to be 61.65% ± 4.61 after 72 h when exposed to phosphate buffer saline (pH 7.4). In vivo studies show a good response against Alzheimer's disease (AD). EGCG-AA-TRANS (82.166%) exhibited a higher percentage of AChE inhibition in comparison to EGCG-TRANS (66.550%) and AA-TRANS (53.466%). Intranasal delivery of EGCG-AA-TRANS resulted in approximately a 5-fold enhancement in memory. Formulation allowed EGCG and AA to accumulate in various organs, including the brain. The results suggest that EGCG-AA-TRANS could be safe and effective for treating AD.

Development of disease-modifying therapies against Alzheimer's disease.

To successfully develop disease-modifying therapies (DMT) against Alzheimer's disease (AD), it is important to target the mild stage of the disease, before the pathological changes progress and dementia symptoms are fully manifested. To this end, the AD Neuroimaging Initiative (ADNI), a large-scale observational study, was initiated in the U.S. with the goal of development of DMT that are effective in the early stages of mild cognitive impairment (MCI) by utilizing imaging and biomarkers. In Japan, J-ADNI enrolled and followed up 537 patients, mainly with MCI, and established a platform for evaluation including amyloid PET, and demonstrated a high similarity in the clinical course of amyloid-positive MCI (prodromal AD) in Japan and the U.S. In 2023, the anti-Aβ antibody lecanemab successfully completed a Phase III clinical trial for early AD (prodromal AD + mild AD dementia) and was granted regulatory approval and made available both in the US and Japan. Also, phase III trial of donanemab was completed successful. The J-TRC study was initiated in Japan as a "trial ready cohort (TRC)" consisting of participants who met the eligibility criteria for participation in preclinical and prodromal AD trials. Based on such a platform, the development of DMT for AD will progress more rapidly in the future.

Network pharmacology and experimental verification to explore the effect of Hedyotis diffusa on Alzheimer's disease.

This study aimed to explore the active components and the effect of Hedyotis diffusa (HD) against Alzheimer's disease (AD) via network pharmacology, molecular docking, and experimental evaluations. We conducted a comprehensive screening process using the TCMSP, Swiss Target Prediction, and PharmMapper databases to identify the active components and their related targets in HD. In addition, we collected potential therapeutic targets of AD from the Gene Cards, Drugbank, and OMIM databases. Afterward, we utilized Cytoscape to establish both protein-protein interaction (PPI) networks and compound-target (C-T) networks. To gain further insights into the functional aspect, we performed GO and KEGG pathway analyses using the David database. Next, we employed Autodock vina to estimate the binding force between the components and the hub genes. To validate our network pharmacology findings, we conducted relevant experiments on Caenorhabditis elegans, further confirming the reliability of our results. Then a total of six active compounds and 149 therapeutic targets were detected. Through the analysis of the association between active compounds, therapeutic targets, and signaling pathways, it was observed that the therapeutic effect of HD primarily encompassed the inhibition of Aβ, suppression of AChE activity, and mitigating oxidative stress. Additionally, our investigation revealed that the key active compounds in HD primarily consisted of iridoids, which exhibited resistance against AD by acting on the Alzheimer's disease pathway and the AGE-RAGE signaling pathway in diabetic complications.

Functionalized nanoparticles to deliver nucleic acids to the brain for the treatment of Alzheimer’s disease

Brain-targeted gene delivery across the blood-brain barrier (BBB) is a significant challenge in the 21st century for the healthcare sector, particularly in developing an effective treatment strategy against Alzheimer’s disease (AD). The Internal architecture of the brain capillary endothelium restricts bio-actives entry into the brain. Additionally, therapy with nucleic acids faces challenges like vulnerability to degradation by nucleases and potential immune responses. Functionalized nanocarrier-based gene delivery approaches have resulted in safe and effective platforms. These nanoparticles (NPs) have demonstrated efficacy in protecting nucleic acids from degradation, enhancing transport across the BBB, increasing bioavailability, prolonging circulation time, and regulating gene expression of key proteins involved in AD pathology. We provided a detailed review of several nanocarriers and targeting ligands such as cell-penetrating peptides (CPPs), endogenous proteins, and antibodies. The utilization of functionalized NPs extends beyond a singular system, serving as a versatile platform for customization in related neurodegenerative diseases. Only a few numbers of bioactive regimens can go through the BBB. Thus, exploring functionalized NPs for brain-targeted gene delivery is of utmost necessity. Currently, genes are considered high therapeutic potential molecules for altering any disease-causing gene. Through surface modification, nanoparticulate systems can be tailored to address various diseases by replacing the target-specific molecule on their surface. This review article presents several nanoparticulate delivery systems, such as lipid NPs, polymeric micelles, exosomes, and polymeric NPs, for nucleic acids delivery to the brain and the functionalization strategies explored in AD research.

The phenylpropionamide extract of hemp (Cannabis sativa L.) seed improves learning memory ability and survival rate by attenuating microglia activation and reducing amyloid deposition via the SIRT1-AMAD10 pathway in APP/PS1 mice

BackgroundFructus cannabis (Hemp seed), the dried and mature fruit of Cannabis sativa L., was reported to have effects against Alzheimer's disease (AD) in different experimental models. However, either chemical composition or mechanisms of action was not clear. Our previous work isolated and identified diverse phenylpropionamides such as cannabisin A-F, caffeoyltyramine and feryroyltyramine from hemp seed, which showed antioxidant and anti-neuroinflammatory activity in cell models. PurposeTo study the anti-AD effect and mechanism of the total phenylpropionamides (TPA) extract from hemp seed using APPswe/PS1dE9 mice model. MethodsTPA extract was prepared via extraction and column chromatography techniques, then analyzed and measured using HPLC, HPLC-MS and Folin-Ciocalteu method. The extract was administered by gavage to APPswe/PS1dE9 mice. The learning memory ability of mice were examined using new object recognition test and Morris water maze. Hematoxylin and Eosin staining was used to observe the morphology of neuronal cells in the hippocampal region of brain tissue; ELISA was used to measure the content of IL-1β, TNF-α, IL-6, superoxide dismutase (SOD), malondialdehyde (MDA) in the brain tissue; the deposition of Aβ protein was measured by immunohistochemistry and Western blotting; the activation of microglia was measured by immunofluorescence. The expression of APP, PS1, SIRT1, and ADAM10 proteins was measured by Western blotting. ResultsFolin-Ciocalteu method showed the total phenylpropionamides content was 238.03 μg caffeic acid equivalent /mg TPA. HPLC and HPLC-MS analysis showed the contents of N-trans-caffeoyltyramine, cannabisin A and B were 20.16 μg/mg, 32.16 μg/mg and 214.35 μg/mg, respectively, in TPA extract. TPA treatment significantly increased the survival rate of APP/PS1 mice, improved the learning and memory ability, reversed the neural cell damage in the hippocampal region, and reduced Aβ deposition and activated microglia in brain tissue. Meanwhile, the administration decreased the neuroinflammatory factors TNF-α, IL-6, IL-1β expression, increased antioxidant enzyme SOD activity, and attenuated MDA expression. Western blotting showed that TPA administration increased SIRT1 and ADAM10 protein expression and decreased APP and PS1 protein expression. ConclusionTPA improved learning memory capacity, increased survival rate, attenuated neuroinflammation, oxidative stress, microglia activation and hippocampal apoptosis, and reduced amyloid deposition via the SIRT1-ADAM10 pathway in APP/PS1 mice.

Acacetin inhibits inflammation by blocking MAPK/NF-κB pathways and NLRP3 inflammasome activation.

Objective: Our preliminary research indicates that acacetin modulates the nucleotide-binding oligomerization domain (NOD)-like receptor pyrin domain containing 3 (NLRP3) inflammasome, providing protection against Alzheimer's Disease (AD) and cerebral ischemic reperfusion injury. The mechanisms of acacetin to inhibit the activation of the NLRP3 inflammasome remain fully elucidated. This study aims to investigate the effects and potential mechanisms of acacetin on various agonists induced NLRP3 inflammasome activation. Methods: A model for the NLRP3 inflammasome activation was established in mouse bone marrow-derived macrophages (BMDMs) using Monosodium Urate (MSU), Nigericin, Adenosine Triphosphate (ATP), and Pam3CSK4, separately. Western blot analysis (WB) was employed to detect Pro-caspase-1, Pro-Interleukin-1β (Pro-IL-1β) in cell lysates, and caspase-1, IL-1β in supernatants. Enzyme-Linked Immunosorbent Assay (ELISA) was used to measured the release of IL-1β, IL-18, and Tumor Necrosis Factor-alpha (TNF-α) in cell supernatants to assess the impact of acacetin on NLRP3 inflammasome activation. The lactate dehydrogenase (LDH) release was also assessed. The Nuclear Factor Kappa B (NF-κB) and Mitogen-Activated Protein Kinase (MAPK) signaling pathways related proteins were evaluated by WB, and NF-κB nuclear translocation was observed via laser scanning confocal microscopy (LSCM). Disuccinimidyl Suberate (DSS) cross-linking was employed to detect oligomerization of Apoptosis-associated Speck-like protein containing a Caspase Recruitment Domain (ASC), and LSCM was also used to observe Reactive Oxygen Species (ROS) production. Inductively Coupled Plasma (ICP) and N-(6-methoxyquinolyl) acetoethyl ester (MQAE) assays were utilized to determined the effects of acacetin on the efflux of potassium (K+) and chloride (Cl-) ions. Results: Acacetin inhibited NLRP3 inflammasome activation induced by various agonists, reducing the release of TNF-α, IL-1β, IL-18, and LDH. It suppressed the expression of Lipopolysaccharides (LPS)-activated Phosphorylated ERK (p-ERK), p-JNK, and p-p38, inhibited NF-κB p65 phosphorylation and nuclear translocation. Acacetin also reduced ROS production and inhibited ASC aggregation, thus suppressing NLRP3 inflammasome activation. Notably, acacetin did not affect K+ and Cl-ions efflux during the activation process. Conclusion: Acacetin shows inhibitory effects on both the priming and assembly processes of the NLRP3 inflammasome, positioning it as a promising new candidate for the treatment of NLRP3 inflammasome-related diseases.

Assessment of the health benefits of phytochemicals in Cynometra cauliflora based on an in silico study against Alzheimer’s disease

Aim: Cynometra cauliflora (namnam) belongs to the family Fabaceae and is native to eastern Peninsular Malaysia. It grows well with an annual rainfall of 1,500–2,000 mm. Even though a considerable amount of research has been carried out with C. caulifora, there is a dearth of information about biomolecules that may pave the way for drug discoveries and food supplements, which is a gap addressed in this study. Methods: The study presented in this paper has identified several antimicrobial, antioxidant, and anti-inflammatory substances, and an in silico approach was used to understand the behaviors of kaempferol-3-O-rhamnoside (K-3-Rh) and β-sitosterol acetate against Alzheimer’s disease (AD). The molecular dynamics (MD) simulations were performed with the selected protein ligand complex of two natural molecules and the synthetic ligand to analyze the dynamic behaviors and binding free energy throughout the 100 ns simulation time. Further, both natural molecules that were investigated comply with Lipinski’s drug-likeness rules. Results: The docking scores of both K-3-Rh and sitosterol were found to be compatible with the synthetic AD drug molecules [donepezil analogue (H0L)] used as a reference in the study. Hence, the phytochemicals of Cynometra caulifora showed comparatively similar potency against acetylcholinesterase (AChE). Conclusions: Overall, the potential binding affinity from molecular docking and static thermodynamics features from MD simulation suggest that K-3-Rh and β-sitosterol acetate could be considered as a potential therapeutic lead to inhibit AChE leading for AD treatment.

Machine learning-based q-RASAR approach for the in silico identification of novel multi-target inhibitors against Alzheimer's disease

In the present research, we present the application of a novel approach, termed the Machine Learning (ML)-Based q-RASAR (quantitative read-across structure-activity relationship) method, for the identification of potential multi-target inhibitors against Alzheimer's disease (AD). The q-RASAR effectively combines the principles of both read-across and 2D QSAR approaches. As a result, it is imperative to take into account similarity-related aspects in the process of developing q-RASAR models. In this investigation, we have implemented ML-based q-RASAR modeling against seven major targets (AChE, BuChE, BACE1, 5-HT6, CDK-5 enzymes, Amyloid precursor protein, and Tau aggregation) of AD using the initially selected features in 2D-QSAR models for the identifications of novel multitarget inhibitors. The models were individually used to check the applicability domain of a pool of 407270 natural products (NPs) obtained from the COCONUT database (https://coconut.naturalproducts.net/download) and provided prioritized compounds for experimental detection of their performance as anti-Alzheimer's drugs. Furthermore, we have also developed the q-RASAAR (quantitative read-across structure-activity-activity relationship) and selectivity-based q-RASAR models to explore the most important features contributing to the dual inhibition against the respective targets. Furthermore, we have applied seven distinct machine learning algorithms to check their influence on the predictive abilities of q-RASAR and q-RASAAR models. Moreover, we have also developed the univariate q-RASAR model, with the RA function as the primary independent variable. Additionally, molecular docking experiments have been conducted to gain insights into the atomic-level molecular interactions between ligands and enzymes. These observations are then juxtaposed with the structural characteristics obtained from models that elucidate the mechanistic aspects of binding events. These proposed models may serve as valuable tools for pinpointing crucial molecular attributes when designing potential drugs for Alzheimer's therapy through the rational design of multi-target inhibitors.

A Review on the Protective Effects of Probiotics against Alzheimer's Disease.

This review summarizes the protective effects of probiotics against Alzheimer's disease (AD), one of the most common neurodegenerative disorders affecting older adults. This disease is characterized by the deposition of tau and amyloid β peptide (Aβ) in different parts of the brain. Symptoms observed in patients with AD include struggles with writing, speech, memory, and knowledge. The gut microbiota reportedly plays an important role in brain functioning due to its bidirectional communication with the gut via the gut-brain axis. The emotional and cognitive centers in the brain are linked to the functions of the peripheral intestinal system via this gut-brain axis. Dysbiosis has been linked to neurodegenerative disorders, indicating the significance of gut homeostasis for proper brain function. Probiotics play an important role in protecting against the symptoms of AD as they restore gut-brain homeostasis to a great extent. This review summarizes the characteristics, status of gut-brain axis, and significance of gut microbiota in AD. Review and research articles related to the role of probiotics in the treatment of AD were searched in the PubMed database. Recent studies conducted using animal models were given preference. Recent clinical trials were searched for separately. Several studies conducted on animal and human models clearly explain the benefits of probiotics in improving cognition and memory in experimental subjects. Based on these studies, novel therapeutic approaches can be designed for the treatment of patients with AD.

Plasma Biomarker Strategy for Selecting Patients With Alzheimer Disease for Antiamyloid Immunotherapies

Antiamyloid immunotherapies against Alzheimer disease (AD) are emerging. Scalable, cost-effective tools will be needed to identify amyloid β (Aβ)-positive patients without an advanced stage of tau pathology who are most likely to benefit from these therapies. Blood-based biomarkers might reduce the need to use cerebrospinal fluid (CSF) or positron emission tomography (PET) for this. To evaluate plasma biomarkers for identifying Aβ positivity and stage of tau accumulation. The cohort study (BioFINDER-2) was a prospective memory-clinic and population-based study. Participants with cognitive concerns were recruited from 2017 to 2022 and divided into a training set (80% of the data) and test set (20%). Baseline values for plasma phosphorylated tau 181 (p-tau181), p-tau217, p-tau231, N-terminal tau, glial fibrillary acidic protein, and neurofilament light chain. Performance to classify participants by Aβ status (defined by Aβ-PET or CSF Aβ42/40) and tau status (tau PET). Number of hypothetically saved PET scans in a plasma biomarker-guided workflow. Of a total 912 participants, there were 499 males (54.7%) and 413 females (45.3%), and the mean (SD) age was 71.1 (8.49) years. Among the biomarkers, plasma p-tau217 was most strongly associated with Aβ positivity (test-set area under the receiver operating characteristic curve [AUC] = 0.94; 95% CI, 0.90-0.97). A 2-cut-point procedure was evaluated, where only participants with ambiguous plasma p-tau217 values (17.1% of the participants in the test set) underwent CSF or PET to assign definitive Aβ status. This procedure had an overall sensitivity of 0.94 (95% CI, 0.90-0.98) and a specificity of 0.86 (95% CI, 0.77-0.95). Next, plasma biomarkers were used to differentiate low-intermediate vs high tau-PET load among Aβ-positive participants. Plasma p-tau217 again performed best, with the test AUC = 0.92 (95% CI, 0.86-0.97), without significant improvement when adding any of the other plasma biomarkers. At a false-negative rate less than 10%, the use of plasma p-tau217 could avoid 56.9% of tau-PET scans needed to identify high tau PET among Aβ-positive participants. The results were validated in an independent cohort (n = 118). This study found that algorithms using plasma p-tau217 can accurately identify most Aβ-positive individuals, including those likely to have a high tau load who would require confirmatory tau-PET imaging. Plasma p-tau217 measurements may substantially reduce the number of invasive and costly confirmatory tests required to identify individuals who would likely benefit from antiamyloid therapies.

Klotho protein concentrations as a function of sex, APOE, family history or Alzheimer’s disease biomarker status in an at‐risk cohort

AbstractBackgroundThe KLOTHO gene encodes for a longevity and neuroprotective klotho hormone. The non‐human animal literature suggests that higher levels of klotho promote resilience against Alzheimer’s disease (AD)‐related neuropathology. Human carriers of the functionally advantageous KLOTHO KL‐VS variant have higher serum klotho levels and show attenuation of proteins involved in AD‐related neuropathology (β‐amyloid (Aβ) and tau). How klotho protein relates to AD neuropathology or risk factors (APOE gene, family history, sex) is less well understood.MethodThe sample consists of 318 middle‐aged and older, cognitively normal adults (MeanAge(SD) = 63.8(6.66); range = 44‐80; 65% female) from the Wisconsin Registry for Alzheimer’s Prevention and the Wisconsin Alzheimer’s Disease Research Center studies. Stratifications of the sample into positive vs. negative AD biomarker status were made using local reference cutpoints measured via cerebrospinal fluid (CSF: Aβ40, Aβ42, total tau, phosphorylated tau, and their respective ratios to Aβ42) or positron emission tomography (PET; β‐amyloid: 11C‐Pittsburgh compound B(PiB); tau: 18F‐MK‐6240). We examined whether baseline serum klotho protein concentrations differed based on AD biomarker status (whether positive (i.e., abnormal) for β‐amyloid or tau) or characteristics related to AD risk.ResultThere were no significant differences in baseline serum klotho concentrations between those considered positive vs. negative for β‐amyloid or tau whether by CSF or PET (P’s&gt;0.19). Females (844 pg/mL) compared to males (765 pg/mL) had significantly higher serum klotho concentrations (F (1,317) = 7.37; P = 0.007). No differences were observed based on APOE4 status or parental AD history (P’s&gt;0.31).ConclusionWe confirm sex‐dependent difference in serum klotho favoring females. No significant differences in serum klotho protein concentrations were observed based on APOE4, AD family history or AD biomarker status (+/‐) in our cohort of middle‐aged and older, cognitively normal adults, albeit enriched for AD risk. While this may seem in contrast to a recent case‐control study (Grøntvedt, 2022) suggesting that klotho protein is associated with β‐amyloid and tau burden and clinical stages of AD, that study measured circulating klotho in plasma and included participants with MCI and AD diagnoses. Our results add to the growing KLOTHO literature and highlight the need for better understanding of the underlying mechanisms for its effects.

The Alzheimer multifactorial therapeutic agent E2F4DN prevents long‐term potentiation and cognitive loss and improves neuronal survival in homozygous 5xFAD mice

AbstractBackgroundDespite many decades of work, we still lack effective therapies against Alzheimer’s disease (AD), likely due to its complex etiology, which requires a multifactorial therapeutic approach. Among the variety of proposed etiological factors, synaptic failure has proof to be an early hallmarks of AD (Nat. Neurosci. 2016;19:443‐453), which precedes neuronal‐death (J. Neurosci. 2006;26:10129‐10140). We have recently shown, using both transgenic mice and gene therapy, that E2F4 is a multifactorial therapeutic target against AD (Neurotherapeutics 2021;18:2484‐2503, Mol. Neurobiol. 2022;59:3016‐3039), likely due to its homeostatic function (Int. J. Mol. Sci. 2022;23:12093). The phosphorylation of two conserved Thr residues of E2F4 is necessary to induce cognitive loss in AD (Neurotherapeutics 2021;18:2484‐2503). Therefore, we have developed a novel therapy consisting in neuronal expression of a dominant negative form of E2F4 (E2F4DN), which cannot be phosphorylated in the conserved Thr residues (Neurotherapeutics 2021;18:2484‐2503, Mol. Neurobiol. 2022;59:3016‐3039). In this work we wanted to verify whether the expression of E2F4DN could correct AD‐associated synaptic dysfunction and neuronal loss in 5xFAD mice, a known mouse model of AD.MethodWe expressed E2F4DN (intravenous administration of AAV‐E2F4DN) in 6 weeks old control and homozygous 5xFAD mice, and stereological, electrophysiological and behavioral studies were performed at 6 months. Cell counting was achieved by unbiased stereology in the CA1 hippocampal region. Cognition was analyzed through novel‐object location and contextual fear conditioning test. Synaptic function (basal synaptic transmission, presynaptic function and long‐term potentiation (LTP)) were measured by electrophysiological recordings of field excitatory postsynaptic potentials in hippocampal CA3‐CA1 synapses. Afterwards, the mechanism underlying memory recovery was evaluated analyzing protein levels of different subunits of the synaptic receptors AMPA and NMDA.ResultE2F4DN expression in neurons prevents neuronal death in the hippocampus (CA1) of homozygous 5xFAD mice, reaching similar values of cell number and CA1 volume to those observed in control mice. Moreover, E2F4DN prevents LTP loss leading to cognitive improvement, as 5xFAD mice treated with our therapy present a noticeable improvement hippocampal‐dependent memory. This effect correlates with the increase of key LTP regulators.ConclusionE2F4‐Based Gene Therapy improves neuronal survival, LTP and cognition, being a safe multifactorial approach for AD treatment.