Alzheimer's Disease Puzzle: Delving into Pathogenesis Hypotheses

Dynamic modeling of astrocyte-neuron interactions under the influence of Aβ deposition

β-amyloid (Aβ) protein accumulation is recognized as a key factor in Alzheimer's disease (AD) pathogenesis. Its effects on astrocyte function appear primarily as disturbances to intracellular calcium signaling, which, in turn, affects neuronal excitability. We propose an innovative neuron-astrocyte interaction model to examine how Aβ accumulation influences astrocyte calcium oscillation and neuronal excitability, emphasizing its significance in AD pathogenesis. This comprehensive model describes not only the response of the astrocyte to presynaptic neuron stimulation but also the release of the downstream signaling glutamate and its consequential feedback on neurons. Our research concentrates on changes within two prominent pathways affected by Aβ: the creation of Aβ astrocyte membrane pores and the enhanced sensitivity of ryanodine receptors. By incorporating these adjustments into our astrocyte model, we can reproduce previous experimental findings regarding aberrant astrocyte calcium activity and neural behavior associated with Aβ from a neural computational viewpoint. Within a specified range of Aβ influence, our numerical analysis reveals that astrocyte cytoplasmic calcium rises, calcium oscillation frequency increases, and the time to the first calcium peak shortens, indicating the disrupted astrocyte calcium signaling. Simultaneously, the neuronal firing rate and cytosolic calcium concentration increase while the threshold current for initiating repetitive firing diminishes, implying heightened neuronal excitability. Given that increased neuronal excitability commonly occurs in early AD patients and correlates with cognitive decline, our findings may highlight the importance of Aβ accumulation in AD pathogenesis and provide a theoretical basis for identifying neuronal markers in the early stages of the disease.

The Role of Inflammation in Neurodegenerative Diseases: Parkinson's Disease, Alzheimer's Disease, and Multiple Sclerosis

Neurodegenerative diseases are a group of conditions that have in common the progressive damage and degeneration of neurons in the central nervous system. This group includes Parkinson's disease, Alzheimer's disease, and multiple sclerosis, among others. In recent years, increasing evidence has pointed to the important role of inflammation in the pathogenesis of these conditions. The occurrence of inflammation in the brain, which is often triggered by pro-inflammatory activation of microglia or astrocytes, can consequently lead to a chronic inflammatory response that contributes to the development of neurodegenerative processes. Inflammatory processes themselves, both within the nervous system and throughout the human body, appear to be central to the initiation and progression of neuronal damage. Understanding the role of inflammation in these diseases may open up new perspectives and opportunities in the future in the development of effective therapies to improve patients' quality of life as the vast majority of cases of patients affected by neurodegenerative diseases continue to be treated symptomatically since causal treatments are lacking. In this review, we provide information on the impact of inflammation on the pathogenesis, course, and potential therapeutic options for selected neurodegenerative diseases. In addition, this article provides a general description of neuroinflammation and the involvement and role of specific cells in the central nervous system.

A Narrative Review Evaluating Diet and Exercise as Complementary Medicine for the Management of Alzheimer's Disease

Alzheimer's Disease (AD) is characterized by complex brain alterations leading to progressive cognitive decline and neuropsychiatric disturbances. This narrative review explores these changes and the potential of diet and exercise as modifiable lifestyle factors to mitigate AD's impact. While some dietary components (e.g., B vitamins, ketogenic diet) and physical activity, particularly aerobic exercise, show promise for improving cognitive function and managing symptoms, evidence for consistent benefits remains limited and requires further investigation. Dietary and exercise research in AD faces significant limitations, including intervention complexity, study design challenges, disease heterogeneity, and difficulties in measuring long-term effects. Addressing these limitations is crucial to fully realize the therapeutic potential of these lifestyle interventions in combating AD.

Disease-modifying effect of donepezil on APP/PS1 mice at different stages of Alzheimer's disease

Despite Alzheimer's disease (AD) representing a significant global health concern, disease-modifying therapeutic options remain elusive. The use of animal models of the disease to develop drugs intended for the treatment of AD does not always predict their efficacy in clinical trials. Our research demonstrates the benefits of a drug-withdrawal approach to screening AD-modifying compounds, focussing on β-amyloid (Aβ)-related pathological changes in APP/PS1 transgenic mice at different stages of the disease. To assess the efficacy of this approach, we examined the AD-modifying effect of donepezil as a reference drug. A significant cognitive decline exhibited by APP/PS1 transgenic mice from 8.4 months of age was accompanied by progressive accumulation of Aβ plaques, decreased synaptophysin and vesicular acetylcholine transporter immunoexpression. Donepezil had a disease-modifying effect, slowing the deterioration of all the pathological markers studied when treatment was started in a pre-symptomatic stage of AD. However, in the group of mice with advanced stage of AD, such disease-modifying effects were not evident.

Causal associations between congenital adrenal hyperplasia and neuropsychiatric conditions- a Mendelian Randomization Study

BACKGROUND

Congenital adrenal hyperplasia (CAH), predominantly caused by 21-hydroxylase deficiency (21-OHD) due to CYP21A2 mutations, disrupts cortisol synthesis and adrenal androgen homeostasis. Observational studies suggest CAH patients exhibit elevated risks of neuropsychiatric disorders, but causal mechanisms remain unestablished. We hypothesized that reduced CYP21A2 expression, reflecting CAH, differentially influences psychiatric outcomes via tissue-specific pathways.

METHODS

Using two-sample Mendelian randomization (MR), we analyzed tissue-specific CYP21A2 expression quantitative trait loci (eQTLs) from adrenal (GTEx v8) and whole blood (GTEx v8 and eQTLGen meta-analysis). Genetic instruments were validated via positive control MR with classical CAH biomarkers. Associations with ten neuropsychiatric disorders were assessed using inverse-variance-weighted MR, supplemented by sensitivity analyses (LCV, SMR) and LD score regression.

RESULTS

Adrenal-derived CYP21A2 downregulation reduced Alzheimer's disease (AD) risk (discovery: OR = 1.245, replication: OR = 1.100) but increased autism spectrum disorder (ASD) susceptibility (discovery: OR = 0.766, replication: OR = 0.659). Conversely, blood-derived eQTLs showed opposing effects that decreased ASD risk (discovery: OR = 1.072, replication: OR = 1.071) and elevated AD risk (OR = 0.968 for both discovery and replication). Both tissues linked reduced CYP21A2 expression to elevated bioavailable testosterone (adrenal: OR = 0.972, p = 0.04; blood: OR = 0.983, p = 0.01), consistent with CAH pathophysiology.

CONCLUSION

Our research indicates that adrenal-driven pathways of CYP21A2 deficiency may reduce the risk of AD while increasing the ASD risk. These findings underscore the pivotal role of endocrine mechanisms in the pathogenesis of neuropsychiatric disorders and advocate for personalized CAH management integrating mental health monitoring.

The autocrine motility factor receptor delays the pathological progression of Alzheimer's disease via regulating the ubiquitination-mediated degradation of APP

BACKGROUND

The ubiquitin-proteasome system (UPS) is responsible for most protein degradation and its malfunction is normally observed in neurodegenerative diseases, including Alzheimer's disease (AD). The autocrine motility factor receptor (AMFR) is an E3 ubiquitin ligase that resides on the endoplasmic reticulum membrane and is involved in various essential biological processes. However, the role of AMFR in AD is still unidentified.

METHODS

Behavioral experiments, including open-field test (OFT), novel object recognition test (NORT) and morris water maze test (MWMT) were conducted after adeno-associated virus (AAV) microinjection into AD model mice. Western blot, co-immunoprecipitation (Co-IP), qPCR and ubiquitination assay were used to analyze AMFR mediated ubiquitination degradation of amyloid precursor protein (APP). ELISA was employed to evaluate changes in amyloidogenic cleavage products of APP following upregulation or downregulation of AMFR in neural cells and analyze AMFR levels in serum and cerebrospinal fluid (CSF) of AD patients.

RESULTS

The progressive decline in AMFR levels was found not only in the hippocampus of APPswe/PSEN1dE9 (APP/PS1) mice but also in the CSF and serum of patients with AD. Moreover, the interaction of AMFR and APP was observed both in hippocampal tissues and brain neurons. In addition, AMFR promoted the K11-linked polyubiquitination of APP to speed up its proteasomal degradation, resulting in decreased Aβ production. Importantly, AMFR overexpression largely rescued the cognitive and synaptic deficits in APP/PS1 mice.

CONCLUSIONS

Taken together, our results demonstrated that AMFR reduced Aβ production and alleviated cognitive impairment by promoting the ubiquitination-mediated degradation of APP. This study indicated that AMFR could have the potential to be a therapeutic target of early-stage AD.

Targeting hypoxia-related pathobiology in Alzheimer's disease: strategies for prevention and treatment

INTRODUCTION

Alzheimer's Disease (AD) is a neurodegenerative condition characterised by cognitive decline and memory impairment. Recent research highlights the important role of hypoxia, a state of insufficient oxygen availability, in exacerbating AD pathogenesis.

MATERIALS AND METHODS

Through the use of a number of different search engines like Scopus, PubMed, Bentham, and Elsevier databases, a literature review was carried out for investigating the role of hypoxia mediated pathobiology in AD. Only peerreviewed articles published in reputable journals in English language were included. Conversely, non-peer-reviewed articles, conference abstracts, and editorials were excluded, along with studies lacking experimental or clinical relevance or those unavailable in full text.

CONCLUSION

Hypoxia exacerbates core pathological features such as oxidative stress, neuroinflammation, mitochondrial dysfunction, amyloid-beta (Aβ) dysregulation, and hyperphosphorylation of tau protein. These interlinked mechanisms establish a self-perpetuating cycle of neuronal damage, accelerating disease progression. Addressing hypoxia as a modifiable risk factor offers potential for both prevention and treatment of AD. Exploring hypoxia and the HIF signalling pathway may help counteract the neuropathological and symptomatic effects of neurodegeneration.

Exosome-Mediated Mitochondrial Regulation: A Promising Therapeutic Tool for Alzheimer's Disease and Parkinson's Disease

Alzheimer's disease (AD) and Parkinson's disease (PD) are representative neurodegenerative diseases with abnormal energy metabolism and altered distribution and deformation of mitochondria within neurons, particularly in brain regions such as the hippocampus and substantia nigra. Neurons have high energy demands; thus, maintaining a healthy mitochondrial population is important for their biological function. Recently, exosomes have been reported to have mitochondrial regulatory potential and antineurodegenerative properties. This review presents the mitochondrial abnormalities in brain cells associated with AD and PD and the potential of exosomes to treat these diseases. Specifically, it recapitulates research on the molecular mechanisms whereby exosomes regulate mitochondrial biogenesis, fusion/fission dynamics, mitochondrial transport, and mitophagy. Furthermore, this review discusses exosome-triggered signaling pathways that regulate nuclear factor (erythroid-derived 2)-like 2-dependent mitochondrial antioxidation and hypoxia inducible factor 1α-dependent metabolic reprogramming. In summary, this review aims to provide a profound understanding of the regulatory effect of exosomes on mitochondrial function in neurons and to propose exosome-mediated mitochondrial regulation as a promising strategy for AD and PD.

Transthyretin as a therapeutic target: the future of disease-modifying therapies for Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is the most common neurodegenerative disease for causing memory deficits and primarily characterized by extracellular deposition of amyloid-β (Aβ) plaques, intracellular neurofibrillary tangles (NFTs), and hyperphosphorylation of tau protein, all are pathological hallmarks for AD. Transthyretin (TTR) is a highly conserved homo-tetrameric protein, primarily synthesized in liver and choroid plexus, and most importantly involved in transport of T3-T4 hormones and retinol.

OBJECTIVES

This review explores the dual role of TTR, with a greater emphasis on its neuroprotective action, particularly in AD.

METHODS

Based on the available literature, TTR's potential as a biomarker in the central nervous system (CNS), focusing its role in stabilizing Aβ aggregation and the senile plaque formation during neurodegeneration. Additionally, TTR's dual roles, in neurodegeneration and neuroprotection are studied, emphasizing its potential for improving AD diagnosis and treatment strategies.

RESULTS

Recent research has revealed that TTR is gradually showcasing its promise in neuroprotection and neuronal viability in AD by binding with Aβ and mitigating its neurotoxic effects. Current preclinical and clinical studies also support that TTR is actively involved in maintaining the blood-brain barrier (BBB) integrity and maintain neurotransmitter balance, all of which offer significant therapeutic promise through TTR stabilizers, such as Tafamidis, Acoramidis, and Vutrisiran, highlighting their potential in AD treatment CONCLUSION: This review concludes that TTR plays bidirectional role and gaining interest as a potential biomarker, though several challenges must be addressed before it can be established a novel therapeutic target in AD management in the modern era of drug discovery.

Advance in peptide-based drug development: delivery platforms, therapeutics and vaccines

The successful approval of peptide-based drugs can be attributed to a collaborative effort across multiple disciplines. The integration of novel drug design and synthesis techniques, display library technology, delivery systems, bioengineering advancements, and artificial intelligence have significantly expedited the development of groundbreaking peptide-based drugs, effectively addressing the obstacles associated with their character, such as the rapid clearance and degradation, necessitating subcutaneous injection leading to increasing patient discomfort, and ultimately advancing translational research efforts. Peptides are presently employed in the management and diagnosis of a diverse array of medical conditions, such as diabetes mellitus, weight loss, oncology, and rare diseases, and are additionally garnering interest in facilitating targeted drug delivery platforms and the advancement of peptide-based vaccines. This paper provides an overview of the present market and clinical trial progress of peptide-based therapeutics, delivery platforms, and vaccines. It examines the key areas of research in peptide-based drug development through a literature analysis and emphasizes the structural modification principles of peptide-based drugs, as well as the recent advancements in screening, design, and delivery technologies. The accelerated advancement in the development of novel peptide-based therapeutics, including peptide-drug complexes, new peptide-based vaccines, and innovative peptide-based diagnostic reagents, has the potential to promote the era of precise customization of disease therapeutic schedule.

Bioactive peptides as multipotent molecules bespoke and designed for Alzheimer's disease

In an increasingly aging world where neurodegenerative diseases (NDs) are exponentially rising, research into more effective and innovative treatments seems paramount. Bioactive peptides (BPs) emerge as promising compounds with revolutionary potential in the treatment of NDs, particularly in well-known conditions like Alzheimer's disease (AD). The biological potential of these compounds is primarily attributed to their drug development advantages such as enhanced penetration, low toxicity, and rapid clearance, as well as, their antioxidant, and anti-inflammatory properties bio-linked to the neuroprotective effect, able to attenuate the multifactorial pathologies of AD. BPs can be sourced from common dietary origins, like animals, plants, marine, and from emerging sources like edible insects. However, to isolate an active BP with beneficial biological effects it must first be released from its parent protein, followed by a synthesis-flow. While in silico approaches can predict a BP's potential bioactivity and structural characteristics, in vitro, cell-based, and in vivo assays should be conducted to ensure these properties. The blood-brain-barrier (BBB) microenvironment and permeability in health or disease state are key factors to consider since they can limit the ability of circulating therapeutical agents, including BPs, to reach the brain. This review focuses on the bioactivity properties of BPs from different dietary protein sources and explores their beneficial effect and neuroprotective activity in AD, unraveling new paths of treatment.

Multiple Adverse Reactions Associated With the Use of Second-Generation Antipsychotics in People With Alzheimer's Disease: A Pharmacovigilance Analysis Based on the FDA Adverse Event Reporting System

BACKGROUND

Alzheimer's disease (AD) is a neurodegenerative condition leading to memory loss, cognitive impairment, and neuropsychiatric symptoms. Second-generation antipsychotics (SGAs) are commonly used to manage these neuropsychiatric symptoms, but their safety profile in patients with AD requires further investigation.

OBJECTIVE

The objective was to evaluate the safety of SGAs in patients with AD by analyzing adverse drug reactions (ADRs) using the US Food and Drug Administration Adverse Event Reporting System (FAERS) database.

METHODS

This study conducted a comprehensive analysis of FAERS data from 2014 to 2023, focusing on ADRs in patients with AD treated with SGAs such as risperidone, quetiapine, olanzapine, clozapine, and aripiprazole. Descriptive, disproportionality, time, and dose analysis were performed using the Bayesian confidence propagation neural network, Weibull, and physiologically based pharmacokinetic model.

RESULTS

Out of 1289 patients with AD treated with SGAs, the most common ADRs involved the nervous system, gastrointestinal system, and cardiac disorders. Disproportionality analysis identified significant positive signals in cardiac, renal, and vascular systems. Quetiapine, risperidone, and olanzapine showed more positive signals compared with clozapine and aripiprazole. Time analysis indicated that cardiovascular ADRs occurred randomly, whereas renal ADRs increased with prolonged use. Dose analysis suggested that small doses of SGAs did not elevate the risk of multiple cardiac, renal, or vascular ADRs.

CONCLUSION AND RELEVANCE

The study underscores the importance of monitoring for ADRs, particularly in the cardiac and renal systems, when using SGAs in patients with AD. Future research incorporating more comprehensive clinical data is warranted to support safe and rational drug utilization.

Recent advancements in the therapeutic approaches for Alzheimer's disease treatment: current and future perspective

Alzheimer's disease (AD) is a complex, incurable neurological condition characterized by cognitive decline, cholinergic neuron reduction, and neuronal loss. Its exact pathology remains uncertain, but multiple treatment hypotheses have emerged. The current treatments, single or combined, alleviate only symptoms and struggle to manage AD due to its multifaceted pathology. The developmental drugs target pivotal disease factors involved in the envisaged hypotheses and include targets such as amyloid aggregation, hyperphosphorylated tau proteins, and receptors like cholinergic, adrenergic, etc. Present-day research focuses on multi-target directed ligands (MTDLs), which inhibit multiple factors simultaneously, helping slow the disease's progression. This review attempts to collate the recent information related to proposed hypotheses for AD etiology. It systematically organizes the advances in various therapeutic options for AD, with a particular emphasis on clinical candidates. Also, it is expected to help medicinal chemists design novel AD treatments based on available information, which could be helpful to AD patients.

Drug repurposing for Alzheimer's disease and other neurodegenerative disorders

Repurposed drugs provide a rich source of potential therapies for Alzheimer's disease (AD) and other neurodegenerative disorders (NDD). Repurposed drugs have information from non-clinical studies, phase 1 dosing, and safety and tolerability data collected with the original indication. Computational approaches, "omic" studies, drug databases, and electronic medical records help identify candidate therapies. Generic repurposed agents lack intellectual property protection and are rarely advanced to late-stage trials for AD/NDD. In this review we define repurposing, describe the advantages and challenges of repurposing, offer strategies for overcoming the obstacles, and describe the key contributions of repurposing to the drug development ecosystem.

Alzheimer's Disease: Exploring Pathophysiological Hypotheses and the Role of Machine Learning in Drug Discovery

Alzheimer's disease (AD) is a major neurodegenerative dementia, with its complex pathophysiology challenging current treatments. Recent advancements have shifted the focus from the traditionally dominant amyloid hypothesis toward a multifactorial understanding of the disease. Emerging evidence suggests that while amyloid-beta (Aβ) accumulation is central to AD, it may not be the primary driver but rather part of a broader pathogenic process. Novel hypotheses have been proposed, including the role of tau protein abnormalities, mitochondrial dysfunction, and chronic neuroinflammation. Additionally, the gut-brain axis and epigenetic modifications have gained attention as potential contributors to AD progression. The limitations of existing therapies underscore the need for innovative strategies. This study explores the integration of machine learning (ML) in drug discovery to accelerate the identification of novel targets and drug candidates. ML offers the ability to navigate AD's complexity, enabling rapid analysis of extensive datasets and optimizing clinical trial design. The synergy between these themes presents a promising future for more effective AD treatments.

Mitochondrial dysfunction in Alzheimer's disease: a key frontier for future targeted therapies

Alzheimer's disease (AD) is the most common neurodegenerative disorder, accounting for approximately 70% of dementia cases worldwide. Patients gradually exhibit cognitive decline, such as memory loss, aphasia, and changes in personality and behavior. Research has shown that mitochondrial dysfunction plays a critical role in the onset and progression of AD. Mitochondrial dysfunction primarily leads to increased oxidative stress, imbalances in mitochondrial dynamics, impaired mitophagy, and mitochondrial genome abnormalities. These mitochondrial abnormalities are closely associated with amyloid-beta and tau protein pathology, collectively accelerating the neurodegenerative process. This review summarizes the role of mitochondria in the development of AD, the latest research progress, and explores the potential of mitochondria-targeted therapeutic strategies for AD. Targeting mitochondria-related pathways may significantly improve the quality of life for AD patients in the future.

Exosomes and non-coding RNAs: bridging the gap in Alzheimer's pathogenesis and therapeutics

Alzheimer's disease (AD) is a neurodegenerative disease that primarily affects the elderly population and is the leading cause of dementia. Meanwhile, the vascular hypothesis suggests that vascular damage occurs in the early stages of the disease, leading to neurodegeneration and hindered waste clearance, which in turn triggers a series of events including the accumulation of amyloid plaques and Tau protein tangles. Non-coding RNAs (ncRNAs), including long noncoding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs), have been found to be involved in the regulation of AD. Furthermore, lncRNAs and circRNAs can act as competitive endogenous RNAs to inhibit miRNAs, and their interactions can form a complex regulatory network. Exosomes, which are extracellular vesicles (EVs), are believed to be able to transfer ncRNAs between cells, thus playing a regulatory role in the brain by crossing the blood-brain barrier (BBB). Exosomes are part of the intercellular carrier system; therefore, utilizing exosomes to deliver drugs to recipient cells might not activate the immune system, making it a potential strategy to treat central nervous system diseases. In this review, we review that AD is a multifactorial neurological disease and that ncRNAs can regulate its multiple pathogenic mechanisms to improve our understanding of the etiology of AD and to simultaneously regulate multiple pathogenic mechanisms of AD through the binding of ncRNAs to exosomes to improve the treatment of AD.

[Cytokine status of patients with Alzheimer's disease]

OBJECTIVE

To study cytokine status in patients with Alzheimer's disease (AD).

MATERIAL AND METHODS

The main group of patients with a confirmed AD included 23 patients with a mean age of 69 [66.2; 77.5] years (6 males, 17 females). Data from 163 apparently healthy subjects (data from the archive of the Centre for Strategic Planning and Management of Biomedical Health Risks of the Federal Medical Biological Agency of Russia) were used as a control. A multiplex enzyme immunoassay (xMAP technology) was performed using a FlexMap 3D multiplex flow fluorimeter. Samples were analyzed for the following cytokines: epidermal growth factor (EGF), fibroblast growth factor (FGF-2), eotaxin, transforming growth factor (TGF-α), granulocyte and granulocyte-macrophage colony-stimulating factors (G-CSF, GM-CSF), Flt-3L, fractalkine, interferon (IFN)-α2, IFN-γ, GRO, interleukins (IL)-10, -12p40, -12p70, -13, -15, -17A, -1RA, -1α, -9, -1β, -2, -3, -4, -5, -6, -7, -8, IP-10, sCD40L, monocyte chemoattractant protein (MCP)-3,-1, macrophage-derived chemokine (MDC), macrophage inflammatory protein (MIP)-1a, MIP-1b, tumor necrosis factors (TNF)-α, TNF-β, vascular endothelial growth factor (VEGF).

RESULTS

The median levels of FGF-2, eotaxin, G-CSF, Flt-3L, GM-CSF, fractalkine, IFN-α2, IFN-γ, MCP-3, IL-1RA, -4, -8, TNF-α in the AD group was higher (more than 2-fold) than in the control group. Of note, the median values of eotaxin, G-CSF, GM-CSF, Flt-3L, IFN-α2, IFN-γ, and TNF-α in the AD group exceeded the 90th percentile of those in the control group.

CONCLUSION

The obtained data indicate significant changes in cytokine status in AD, with increased pro-inflammatory cytokines and activated neuroprotective mechanisms.

Physiopathological mechanisms underlying Alzheimer's disease: a narrative review

The neuropathological signature of Alzheimer's disease (AD) comprises mainly amyloid plaques, and neurofibrillary tangles, resulting in synaptic and neuronal loss. These pathological structures stem from amyloid dysfunctional metabolism according to the amyloid cascade hypothesis, leading to the formation of plaques, and apparently inducing the initiation of the abnormal tau pathway, with phosphorylation and aggregation of these proteins, ultimately causing the formation of tangles. In this narrative review, the existing hypothesis related to the pathophysiology of AD were compiled, and biological pathways were highlighted in order to identify the molecules that could represent biological markers of the disease, necessary to establish early diagnosis, as well as the selection of patients for therapeutical interventional strategies.

Exploring the Impact of Semaglutide on Cognitive Function and Anxiety-Related Behaviors in a Murine Model of Alzheimer's Disease

BACKGROUND

Alzheimer's disease (AD), the most prevalent form of dementia, is characterized by progressive cognitive decline and behavioral disturbances, with an increasing incidence as the global population ages. This study investigates the effects of semaglutide (SEM), a glucagon-like peptide-1 analog, on cognitive function and anxiety-like behavior in a transgenic murine model of AD.

METHODS

20 mice were randomly distributed into the following groups (n = 5): (WT + VEH) group: C57BL/6J + saline, (WT + SEM) group: C57BL/6J + semaglutide, (AD + VEH) group: AD + saline, (AD + SEM) group: AD + semaglutide. The animals underwent a four-week treatment, during which we monitored blood glucose levels, body weight, and responses in an open field test, novel object recognition test, social chamber test, and 0-maze test.

RESULTS

Post-treatment, SEM significantly reduced blood glucose levels in AD mice, aligning them with those of wild-type controls. Cognitive assessments indicated an improvement in the investigation index for SEM-treated mice compared to those receiving a vehicle, suggesting cognitive benefits. Although SEM did not significantly enhance motor and exploratory activities, it displayed a potential anxiolytic effect, particularly evident in the combined anxiety index, with notable differences observed before and after treatment in the AD group.

CONCLUSIONS

The findings of this pilot study suggest that SEM may play a dual role in managing AD by improving glycemic control and potentially enhancing cognitive function. As the landscape of AD treatment evolves, the comprehensive approach of utilizing SEM could pave the way for innovative interventions targeting the complex interplay of metabolic and cognitive dysfunctions in this challenging neurodegenerative disorder.

Chemical-Driven Amyloid Clearance for Therapeutics and Diagnostics of Alzheimer's Disease

A century ago, German neurologist Alois Alzheimer documented the first case of Alzheimer's disease (AD), illuminating cognitive impairments associated with the presence of abnormal protein clusters, including amyloid plaques and tau tangles, within the brain. In a typical physiological state, the equilibrium of amyloid-β (Aβ) levels is maintained, but aging can precipitate disruptions in the homeostasis of Aβ due to its overproduction, impaired clearance, and other factors, ultimately leading to its accumulation. Although the link between Aβ aggregates and neurodegeneration has long made Aβ a promising target for AD, decades without successful drug development targeting Aβ have generated skepticism regarding the efficacy of this strategy for AD therapy. However, recent approvals of anti-Aβ antibody drugs by the FDA, including aducanumab (Aduhelm), lecanemab (Leqembi), and donanemab (Kisunla), have prompted a re-evaluation of this perspective. These therapies have demonstrated efficacy in reducing brain Aβ levels, thereby decelerating disease progression and reaffirming Aβ as a key target. Despite advancements, immunotherapies are accompanied by considerable disadvantages, including adverse effects, high costs, and cumbersome administration. To address these limitations, our research has focused on developing small molecules that can mitigate the challenges of antibody treatments while offering practical and accessible options. We identified 4-(2-hydroxyethyl)-1-piperazine propanesulfonic acid (EPPS) as a promising compound that significantly reduces aggregated Aβ in the brain and enhances behavior in AD rodent models. Following administration, EPPS penetrates the blood-brain barrier (BBB) and binds to toxic Aβ aggregates, subsequently breaking them down into nontoxic monomers. This leads to two significant outcomes: a reduction of Aβ aggregates in the brain and a subsequent increase in Aβ monomers in blood. The monomeric Aβ, unlike its aggregated form, can now traverse the BBB and enter the bloodstream. This mechanism provides an innovative approach to AD treatment and diagnosis. By detaching cerebral Aβ aggregates, EPPS facilitates Aβ clearance and addresses a key pathological feature of AD. Concurrently, the increase in blood Aβ levels offers a potential biomarker for monitoring treatment efficacy and disease progression, thereby revolutionizing both AD treatment and diagnosis. Investigating the detailed mode of action of drug candidates requires structural information about a target protein. Unfortunately, the unstable and heterogeneous nature of Aβ aggregates, which form larger clusters, complicates the identification of these structures. Therefore, we developed new tools for screening small molecules by immobilizing monomeric Aβ and its fragments on plates. This allows us not only to identify novel compounds that target Aβ but also to elucidate their mechanisms of action, enabling the development of Aβ-targeting therapeutic avenues in AD. We believe that our work on chemical-driven amyloid clearance through small molecules represents an advance in AD research, offering chemical diversity and straightforward, economical development processes. In clinical practice, we anticipate that these findings will contribute to the development of patient-friendly therapeutic and diagnostic interventions, including self-administered and orally available options, thereby enhancing disease management and overall quality of life for individuals with AD. Furthermore, this research extends beyond AD, potentially offering insights into other neurodegenerative diseases characterized by protein aggregation.

Therapeutic potential of mackerel-derived peptides and the synthetic tetrapeptide TVGF for sleep disorders in a light-induced anxiety zebrafish model

Introduction

Anxiety-like insomnia is a known risk factor for the onset and worsening of certain neurological diseases, including Alzheimer's disease. Due to the adverse effects of current anti-insomnia medications, such as drug dependence and limited safety, researchers are actively exploring natural bioactive compounds to mitigate anxiety-like insomnia with fewer side effects. Mackerel (Pneumatophorus japonicus), a traditional Chinese medicine, is known for its tonic effects and is commonly used to treat neurasthenia. The use of mackerel protein extract has been shown to effectively improve symptoms of light-induced anxiety-like insomnia in a zebrafish model.

Methods

This study examines the effects of mackerel bone peptides (MW < 1 kDa, MBP1) and the synthetic peptide Thr-Val-Gly-Phe (TVGF) on light-induced anxiety-like insomnia in zebrafish. The evaluation is conducted through behavioral observation, biochemical marker analysis, and gene transcriptome profiling.

Results

MBP1 significantly alleviated abnormal hyperactivity and restored neurotransmitter levels (dopamine and γ-aminobutyric acid) to normal. Moreover, it mitigated oxidative stress by reducing reactive oxygen species production and malonaldehyde levels, while enhancing antioxidant enzyme activities (superoxide dismutase and catalase). This was further attributed to the regulation of lipid accumulation and protein homeostasis. Furthermore, MBP1 ameliorated sleep disturbances primarily by restoring normal expression levels of genes involved in circadian rhythm (per2 and sik1) and visual function (opn1mw2, zgc:73075, and arr3b). Molecular docking analysis indicated that TVGF exhibited good affinity for receptors linked to sleep disturbances, including IL6, HTR1A, and MAOA. TVGF exhibited sedative effects in behavioral assays, mainly mediated by regulating the normal expression of genes associated with circadian rhythm (cry1bb, cry1ba, per2, per1b and sik1), visual function (opn1mw1, gnb3b, arr3b, gnat2), purine metabolism (pnp5a), and stress recovery (fkbp5).

Discussion

These findings suggest that MBP1 and TVGF could be promising therapies for light-induced anxiety-like insomnia in humans, offering safer alternatives to current medications. Additionally, the regulation of genes related to circadian rhythm and visual perception may be a key mechanism by which MBP1 and TVGF effectively relieve anxiety-like insomnia.

Supramolecular approach to the design of nanocarriers for antidiabetic drugs: targeted patient-friendly therapy

Diabetes and its complications derived are among serious global health concerns that critically deteriorate the quality of life of patients and, in some cases, result in lethal outcome. Herein, general information on the pathogenesis, factors aggravating the course of the disease and drugs used for the treatment of two types of diabetes are briefly discussed. The aim of the review is to introduce supramolecular strategies that are currently being developed for the treatment of diabetes mellitus and that present a very effective alternative to chemical synthesis, allowing the fabrication of nanocontainers with switchable characteristics that meet the criteria of green chemistry. Particular attention is paid to organic (amphiphilic and polymeric) formulations, including those of natural origin, due to their biocompatibility, low toxicity, and bioavailability. The advantages and limitations of different nanosystems are discussed, with emphasis on their adaptivity to noninvasive administration routes.<br>The bibliography includes 378 references.

The ROSMAP project: aging and neurodegenerative diseases through omic sciences

The Religious Order Study and Memory and Aging Project (ROSMAP) is an initiative that integrates two longitudinal cohort studies, which have been collecting clinicopathological and molecular data since the early 1990s. This extensive dataset includes a wide array of omic data, revealing the complex interactions between molecular levels in neurodegenerative diseases (ND) and aging. Neurodegenerative diseases (ND) are frequently associated with morbidity and cognitive decline in older adults. Omics research, in conjunction with clinical variables, is crucial for advancing our understanding of the diagnosis and treatment of neurodegenerative diseases. This summary reviews the extensive omics research-encompassing genomics, transcriptomics, proteomics, metabolomics, epigenomics, and multiomics-conducted through the ROSMAP study. It highlights the significant advancements in understanding the mechanisms underlying neurodegenerative diseases, with a particular focus on Alzheimer's disease.

An in-silico approach - molecular docking analysis of flavonoids against GSK-3β and TNF-α targets in Alzheimer's disease

INTRODUCTION

Drug development for Alzheimer's disease has one of the greatest failure rates of any therapeutic field and AD is still incurable. Glycogen synthase kinase-3β is a critical enzyme implicated in the pathogenesis of AD, particularly in the hyperphosphorylation of tau protein, which leads to the formation of neurofibrillary tangles. TNF-α also plays a significant role in the pathogenesis of Alzheimer's disease by promoting neuroinflammation, contributing to the formation of amyloid plaques and neurofibrillary tangles, impairing synaptic function, and disrupting the balance of neurotrophic factors. Phytomedicine has numerous advantages over synthetic medications, acting multiple mode of action, including being less toxic and having fewer adverse effects. Flavonoids act as a promising therapeutic target for treating Alzheimer's disease. The present work investigates the anti-AD potentials of 35 flavonoids for the inhibition of GSK-3β and TNF-α.

METHODS

The physicochemical, pharmacokinetic parameters, toxicity profile and drug-likeliness of the selected 35 flavonoids were predicted using SwissADME & OSIRIS data Warrier property explorer web tool. All flavonoids were selected for docking studies on GSK-3β and TNF-α protein using Autodock 4.2.1.

RESULTS

The predictions of this study suggested that among the selected 35 flavonoids, Top 3 flavonoids, such as Epicatechin gallate -10.93 kcal/mol, Fisetin -9.44 kcal/mol and Eriodictyol -8.54 kcal/mol for GSK-3β targets. TNF-α Fisetin -11.52 kcal/mol, Sterubin -10.87 kcal/mol, Biochainin A -10.69 kcal/mol were compared with standard drug donepezil.

CONCLUSION

Therefore, these flavonoids could be utilized as possible leads for the structure-based design in the advancement of new, strong Anti-Alzheimer's agents. However, more invitro and invivo analyses are required to finally confirm the outcomes of this research.

Peripheral GFAP and NfL as early biomarkers for dementia: longitudinal insights from the UK Biobank

BACKGROUND

Peripheral glial fibrillary acidic protein (GFAP) and neurofilament light chain (NfL) are sensitive markers of neuroinflammation and neuronal damage. Previous studies with highly selected participants have shown that peripheral GFAP and NfL levels are elevated in the pre-clinical phase of Alzheimer's disease (AD) and dementia. However, the predictive value of GFAP and NfL for dementia requires more evidence from population-based cohorts.

METHODS

This was a prospective cohort study to evaluate UK Biobank participants enrolled from 2006 to 2010 using plasma GFAP and NfL measurements measured by Olink Target Platform and prospectively followed up for dementia diagnosis. Primary outcome was the risk of clinical diagnosed dementia. Secondary outcomes were cognition. Linear regression was used to assess the associations between peripheral GFAP and NfL with cognition. Cox proportional hazard models with cross-validations were used to estimate associations between elevated GFAP and NfL with risk of dementia. All models were adjusted for covariates.

RESULTS

A subsample of 48,542 participants in the UK Biobank with peripheral GFAP and NfL measurements were evaluated. With an average follow-up of 13.18 ± 2.42 years, 1312 new all-cause dementia cases were identified. Peripheral GFAP and NfL increased up to 15 years before dementia diagnosis was made. After strictly adjusting for confounders, increment in NfL was found to be associated with decreased numeric memory and prolonged reaction time. A greater annualized rate of change in GFAP was significantly associated with faster global cognitive decline. Elevation of GFAP (hazard ratio (HR) ranges from 2.25 to 3.15) and NfL (HR ranges from 1.98 to 4.23) increased the risk for several types of dementia. GFAP and NfL significantly improved the predictive values for dementia using previous models (area under the curve (AUC) ranges from 0.80 to 0.89, C-index ranges from 0.86 to 0.91). The AD genetic risk score and number of APOE*E4 alleles strongly correlated with GFAP and NfL levels.

CONCLUSIONS

These results suggest that peripheral GFAP and NfL are potential biomarkers for the early diagnosis of dementia. In addition, anti-inflammatory therapies in the initial stages of dementia may have potential benefits.

New Multitarget Molecules Derived from Caffeine as Potentiators of the Cholinergic System

Cholinergic deficit is a characteristic factor of several pathologies, such as myasthenia gravis, some types of congenital myasthenic syndromes, and Alzheimer's Disease. Two molecular targets for its treatment are acetylcholinesterase (AChE) and nicotinic acetylcholine receptor (nAChR). In previous studies, we found that caffeine behaves as a partial nAChR agonist and confirmed that it inhibits AChE. Here, we present new bifunctional caffeine derivatives consisting of a theophylline ring connected to amino groups by different linkers. All of them were more potent AChE inhibitors than caffeine. Furthermore, although some of them also activated muscle nAChR as partial agonists, not all of them stabilized nAChR in its desensitized conformation. To understand the molecular mechanism underlying these results, we performed docking studies on AChE and nAChR. The nAChR agonist behavior of the compounds depends on their accessory group, whereas their ability to stabilize the receptor in a desensitized state depends on the interactions of the linker at the binding site. Our results show that the new compounds can inhibit AChE and activate nAChR with greater potency than caffeine and provide further information on the modulation mechanisms of pharmacological targets for the design of novel therapeutic interventions in cholinergic deficit.

Insights into amyloid precursor protein target through PPI network analysis

Alzheimer's disease (AD) is the leading cause of dementia worldwide with therapeutic lacunae till date. The beta-amyloid (Aβ) accumulation triggers AD pathogenesis, though clinical trials lowering Aβ have not altered disease outcomes suggesting other interacting factors to be identified for drug design of AD. Therefore, it is of interest to identify potential hub proteins interlinked with disease-driving pathways using a network-based approach for AD therapeutic designing. Literature mining was done to identify proteins implicated in AD etiology. Protein-protein interactions (PPIs) were retrieved from the STRING database and merged into a single network using Cytoscape 3.10.1. The hub proteins involved in AD etiology were predicted based on the topological algorithms of CytoHubba. Six major proteins, with STRING database identifiers - APP, BACE1, PSEN1, MAPT, APOE4 and TREM2, were identified to be involved in AD pathogenesis. The merged network of PPIs of these proteins contained 51 nodes and 211 edges, as predicted by Analyzer module of Cytoscape. The Amyloid precursor protein (APP) emerged as the highest-scoring hub protein across multiple centrality measures and topological algorithms. Thus, current data provides evidence to support the ongoing investigation of APP's multifaceted functions and therapeutic potential for AD.

Food-Derived Peptides: Beneficial CNS Effects and Cross-BBB Transmission Strategies

Food-derived peptides, as dietary supplements, have significant effects on promoting brain health and relieving central nervous system (CNS) diseases. However, the blood-brain barrier (BBB) greatly limits their in-brain bioavailability. Thus, overcoming the BBB to target the CNS is a major challenge for bioactive peptides in the prevention and treatment of CNS diseases. This review discusses improvement in the neuroprotective function of food-derived active peptides in CNS diseases, as well as the source of BBB penetrating peptides (BBB-shuttles) and the mechanism of transmembrane transport. Notably, this review also discusses various peptide modification methods to overcome the low permeability and stability of the BBB. Lipification, glycosylation, introduction of disulfide bonds, and cyclization are effective strategies for improving the penetration efficiency of peptides through the BBB. This review provides a new prospective for improving their neuroprotective function and developing treatments to delay or even prevent CNS diseases.

Novel harmine derivatives as potent acetylcholinesterase and amyloid beta aggregation dual inhibitors for management of Alzheimer's disease

In this study, a series of potential ligands for the treatment of AD were synthesised and characterised as novel harmine derivatives modified at position 9 with benzyl piperazinyl. In vitro studies revealed that the majority of the derivatives exhibited moderate to potent inhibition against hAChE and Aβ1 - 42 aggregation. Notably, compounds 13 and 17d displayed potent drug - likeness and ADMET properties, demonstrating remarkable inhibitory activities towards AChE (IC50 = 58.76 nM and 89.38 nM, respectively) as well as Aβ aggregation (IC50 = 9.31 μM and 13.82 μM, respectively). More importantly, compounds 13 and 17d showed exceptional neuroprotective effects against Aβ1 - 42-induced SH - SY5Y damage, while maintaining low toxicity in SH - SY5Y cells. Further exploration of the mechanism through kinetic studies and molecular modelling confirmed that compound 13 could interact with both the CAS and the PAS of AChE. These findings suggested that harmine derivatives hold great potential as dual - targeted candidates for treating AD.