Amyloid precursor protein processing and Alzheimer's disease

AAV mediated carboxyl terminus of Hsp70 interacting protein overexpression mitigates the cognitive and pathological phenotypes of APP/PS1 mice

JOURNAL/nrgr/04.03/01300535-202501000-00033/figure1/v/2024-05-14T021156Z/r/image-tiff The E3 ubiquitin ligase, carboxyl terminus of heat shock protein 70 (Hsp70) interacting protein (CHIP), also functions as a co-chaperone and plays a crucial role in the protein quality control system. In this study, we aimed to investigate the neuroprotective effect of overexpressed CHIP on Alzheimer's disease. We used an adeno-associated virus vector that can cross the blood-brain barrier to mediate CHIP overexpression in APP/PS1 mouse brain. CHIP overexpression significantly ameliorated the performance of APP/PS1 mice in the Morris water maze and nest building tests, reduced amyloid-β plaques, and decreased the expression of both amyloid-β and phosphorylated tau. CHIP also alleviated the concentration of microglia and astrocytes around plaques. In APP/PS1 mice of a younger age, CHIP overexpression promoted an increase in ADAM10 expression and inhibited β-site APP cleaving enzyme 1, insulin degrading enzyme, and neprilysin expression. Levels of HSP70 and HSP40, which have functional relevance to CHIP, were also increased. Single nuclei transcriptome sequencing in the hippocampus of CHIP overexpressed mice showed that the lysosomal pathway and oligodendrocyte-related biological processes were up-regulated, which may also reflect a potential mechanism for the neuroprotective effect of CHIP. Our research shows that CHIP effectively reduces the behavior and pathological manifestations of APP/PS1 mice. Indeed, overexpression of CHIP could be a beneficial approach for the treatment of Alzheimer's disease.

Implications of liquid-liquid phase separation and ferroptosis in Alzheimer's disease

Neuronal cell demise represents a prevalent occurrence throughout the advancement of Alzheimer's disease (AD). However, the mechanism of triggering the death of neuronal cells remains unclear. Its potential mechanisms include aggregation of soluble amyloid-beta (Aβ) to form insoluble amyloid plaques, abnormal phosphorylation of tau protein and formation of intracellular neurofibrillary tangles (NFTs), neuroinflammation, ferroptosis, oxidative stress, liquid-liquid phase separation (LLPS) and metal ion disorders. Among them, ferroptosis is an iron-dependent lipid peroxidation-driven cell death and emerging evidences have demonstrated the involvement of ferroptosis in the pathological process of AD. The sensitivity to ferroptosis is tightly linked to numerous biological processes. Moreover, emerging evidences indicate that LLPS has great impacts on regulating human health and diseases, especially AD. Soluble Aβ can undergo LLPS to form liquid-like droplets, which can lead to the formation of insoluble amyloid plaques. Meanwhile, tau has a high propensity to condensate via the mechanism of LLPS, which can lead to the formation of NFTs. In this review, we summarize the most recent advancements pertaining to LLPS and ferroptosis in AD. Our primary focus is on expounding the influence of Aβ, tau protein, iron ions, and lipid oxidation on the intricate mechanisms underlying ferroptosis and LLPS within the domain of AD pathology. Additionally, we delve into the intricate cross-interactions that occur between LLPS and ferroptosis in the context of AD. Our findings are expected to serve as a theoretical and experimental foundation for clinical research and targeted therapy for AD.

Current pharmacophore based approaches for the development of new anti-Alzheimer's agents

Amyloid beta peptide (Aβ) and hyperphosphorylated neuronal tau proteins accumulate in neurofibrillary tangles in Alzheimer's disease (AD), a chronic neurodegenerative illness. Chronic inflammation in the brain, which promotes disease progression, is another feature of the Alzheimer's disease pathogenesis. Approximately 60-70 % of dementia cases are caused by AD. The development of effective therapies for the treatment of AD is urgently needed given the severity of the condition and its rapidly rising prevalence. Cholinesterase inhibitors, beta-amyloid (A-beta), tau inhibitors, and many other medications are currently used as preventive medicine for AD. These medications can temporarily suppress dementia symptoms but cannot halt or reverse the disease's progression. Many international pharmaceutical companies have tried numerous times to develop an amyloid clearing medication based on the amyloid hypothesis, but without success. Therefore, the amyloid theory may not be entirely plausible. This review mainly covers the recent and important reported pharmacophores as the starting point to discuss already known targets like tau, butyrylcholinesterase, amyloid beta, and acetylcholinesterase and covers the literature between years 2019-2024.

Innovative pathological network-based multitarget approaches for Alzheimer's disease treatment

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease and is a major health threat globally. Its prevalence is forecasted to exponentially increase during the next 30 years due to the global aging population. Currently, approved drugs are merely symptomatic, being ineffective in delaying or blocking the relentless disease advance. Intensive AD research describes this disease as a highly complex multifactorial disease. Disclosure of novel pathological pathways and their interconnections has had a major impact on medicinal chemistry drug development for AD over the last two decades. The complex network of pathological events involved in the onset of the disease has prompted the development of multitarget drugs. These chemical entities combine pharmacological activities toward two or more drug targets of interest. These multitarget-directed ligands are proposed to modify different nodes in the pathological network aiming to delay or even stop disease progression. Here, we review the multitarget drug development strategy for AD during the last decade.

The growth rate of senile plaques is determined by the competition between the rate of deposition of free Aβ aggregates into plaques and the autocatalytic production of free Aβ aggregates

The formation of amyloid beta (Aβ) deposits (senile plaques) is one of the hallmarks of Alzheimer's disease (AD). This study investigates what processes are primarily responsible for their formation. A model is developed to simulate the diffusion of amyloid beta (Aβ) monomers, the production of free Aβ aggregates through nucleation and autocatalytic processes, and the deposition of these aggregates into senile plaques. The model suggests that efficient degradation of Aβ monomers alone may suffice to prevent the growth of senile plaques, even without degrading Aβ aggregates and existing plaques. This is because the degradation of Aβ monomers interrupts the supply of reactants needed for plaque formation. The impact of Aβ monomer diffusivity is demonstrated to be small, enabling the application of the lumped capacitance approximation and the derivation of approximate analytical solutions for limiting cases with both small and large rates of Aβ aggregate deposition into plaques. It is found that the rate of plaque growth is governed by two competing processes. One is the deposition rate of free Aβ aggregates into senile plaques. If this rate is small, the plaque grows slowly. However, if the rate of deposition of Aβ aggregates into senile plaques is very large, the free Aβ aggregates are removed from the intracellular fluid by deposition into the plaques, leaving insufficient free Aβ aggregates to catalyze the production of new aggregates. This suggests that under certain conditions, Aβ plaques may offer neuroprotection and impede their own growth. Additionally, it indicates that there exists an optimal rate of deposition of free Aβ aggregates into the plaques, at which the plaques attain their maximum size.

MAMs and Mitochondrial Quality Control: Overview and Their Role in Alzheimer's Disease

Alzheimer's disease (AD) represents the most widespread neurodegenerative disorder, distinguished by a gradual onset and slow progression, presenting a substantial challenge to global public health. The mitochondrial-associated membrane (MAMs) functions as a crucial center for signal transduction and material transport between mitochondria and the endoplasmic reticulum, playing a pivotal role in various pathological mechanisms of AD. The dysregulation of mitochondrial quality control systems is considered a fundamental factor in the development of AD, leading to mitochondrial dysfunction and subsequent neurodegenerative events. Recent studies have emphasized the role of MAMs in regulating mitochondrial quality control. This review will delve into the molecular mechanisms underlying the imbalance in mitochondrial quality control in AD and provide a comprehensive overview of the role of MAMs in regulating mitochondrial quality control.

Selective fluorescent labeling of cellular proteins and its biological applications

Proteins, which are ubiquitous in cells and critical to almost all cellular functions, are indispensable for life. Fluorescence imaging of proteins is key to understanding their functions within their native milieu, as it provides insights into protein localization, dynamics, and trafficking in living systems. Consequently, the selective labeling of target proteins with fluorophores has emerged as a highly active research area, encompassing bioorganic chemistry, chemical biology, and cell biology. Various methods for selectively labeling proteins with fluorophores in cells and tissues have been established and are continually being developed to visualize and characterize proteins. This review highlights research findings reported since 2018, with a focus on the selective labeling of cellular proteins with small organic fluorophores and their biological applications in studying protein-associated biological events. We also discuss the strengths and weaknesses of each labeling approach for their utility in living systems.

Designing and optimizing AAV-mediated gene therapy for neurodegenerative diseases: from bench to bedside

Recombinant adeno-associated viruses (rAAVs) have emerged as an attractive tool for gene delivery, and demonstrated tremendous promise in gene therapy and gene editing-therapeutic modalities with potential "one-and-done" treatment benefits compared to conventional drugs. Given their tropisms for the central nervous system (CNS) across various species including humans, rAAVs have been extensively investigated in both pre-clinical and clinical studies targeting neurodegenerative disease. However, major challenges remain in the application of rAAVs for CNS gene therapy, such as suboptimal vector design, low CNS transduction efficiency and specificity, and therapy-induced immunotoxicity. Therefore, continuing efforts are being made to optimize the rAAV vectors from their "core" genetic payloads to their "coat" or capsid structure. In this review, we describe current approaches for rAAV vector design tailored for transgene expression in the CNS, summarize the development of CNS-targeting AAV serotypes, and highlight recent advancements in AAV capsid engineering, aimed at generating a new generation of rAAVs with improved CNS tropism. Additionally, we discuss various administration routes for delivering rAAVs to the CNS and provide an overview of AAV-mediated gene therapies currently under investigation in clinical trials for the treatment of neurodegenerative diseases.

Single-cell m6A profiling in the mouse brain uncovers cell type-specific RNA methylomes and age-dependent differential methylation

N6-methyladenosine (m6A) is an abundant mRNA modification in the brain that has important roles in neurodevelopment and brain function. However, because of technical limitations, global profiling of m6A sites within the individual cell types that make up the brain has not been possible. Here, we develop a mouse model that enables transcriptome-wide m6A detection in any tissue of interest at single-cell resolution. We use these mice to map m6A across different brain regions and within single cells of the mouse cortex and discover a high degree of shared methylation across brain regions and cell types. However, we also identify a small number of differentially methylated mRNAs in neurons that encode important regulators of neuronal signaling, and we discover that microglia have lower levels of m6A than other cell types. Finally, we perform single-cell m6A mapping in aged mice and identify many transcripts with age-dependent changes in m6A.

Molecular mechanisms of mitochondrial homeostasis regulation in neurons and possible therapeutic approaches for Alzheimer's disease

Alzheimer's disease (AD) is a neurological disease with memory loss and cognitive decline, which affects a large proportion of the aging population. Regrettably, there are no drug to reverse or cure AD and drug development for the primary theory of amyloid beta deposition has mostly failed. Therefore, there is an urgent need to investigate novel strategies for preventing AD. Recent studies demonstrate that imbalance of mitochondrial homeostasis is a driver in Aβ accumulation, which can lead to the occurrence and deterioration of cognitive impairment in AD patients. This suggests that regulating neuronal mitochondrial homeostasis may be a new strategy for AD. We summarize the importance of mitochondrial homeostasis in AD neuron and its regulatory mechanisms in this review. In addition, we summarize the results of studies indicating mitochondrial dysfunction in AD subjects, including impaired mitochondrial energy production, oxidative stress, imbalance of mitochondrial protein homeostasis, imbalance of fusion and fission, imbalance of neuronal mitochondrial biogenesis and autophagy, and altered mitochondrial motility, in hope of providing possible therapeutic approaches for AD.

Immunotherapy for Parkinson's Disease and Alzheimer's Disease: A Promising Disease-Modifying Therapy

Alzheimer's disease (AD) and Parkinson's disease (PD) are two neurodegenerative diseases posing a significant disease burden due to their increasing prevalence and socio-economic cost. Traditional therapeutic approaches for these diseases exist but provide limited symptomatic relief without addressing the underlying pathologies. This review examines the potential of immunotherapy, specifically monoclonal antibodies (mAbs), as disease-modifying treatments for AD and PD. We analyze the pathological mechanisms of AD and PD, focusing on the roles of amyloid-beta (Aβ), tau (τ), and alpha-synuclein (α-syn) proteins. We discuss the latest advancements in mAb therapies targeting these proteins, evaluating their efficacy in clinical trials and preclinical studies. We also explore the challenges faced in translating these therapies from bench to bedside, including issues related to safety, specificity, and clinical trial design. Additionally, we highlight future directions for research, emphasizing the need for combination therapies, improved biomarkers, and personalized treatment strategies. This review aims to provide insights into the current state and future potential of antibody-based immunotherapy in modifying the course of AD and PD, ultimately improving patient outcomes and quality of life.

Active Site Environment and Reactivity of Copper-Aβ in Membrane Mimetic SDS Micellar Environment

Alzheimer's disease (AD) is characterized by the abnormal aggregation of amyloid β (Aβ) peptide in extracellular deposits generated upon proteolysis of Amyloid Precursor Protein (APP). While copper (Cu(II)) binds to Aβ in soluble oligomeric and aggregated forms, its interaction with membrane-bound Aβ remains elusive. Investigating these interactions is crucial for understanding AD pathogenesis. Here, utilizing SDS micelles as a simplified membrane mimic, we focus on elucidating the interplay between membrane-anchored Aβ and copper, given their pivotal roles in AD. We employed spectroscopic techniques including UV, CD, and EPR to characterize the active site of Cu-Aβ complexes. Our findings demonstrate that copper interacts with Aβ peptides in membrane-mimicking micellar environments similarly to aqueous buffer solutions. Cu-Aβ complexes in this medium also induce higher hydrogen peroxide (H2O2) production, potentially contributing to AD-related oxidative stress. Moreover, we observe an increased oxidation rate of neurotransmitter such as dopamine by Cu-Aβ complexes. These results enhance our understanding of Cu-Aβ interactions in AD pathology and offer insights into potential therapeutic interventions targeting this interaction.

Cannabidiol and neurodegeneration: From molecular mechanisms to clinical benefits

Neurodegenerative disorders (NDs) such as Alzheimer's disease, Parkinson's disease, Huntington's disease, multiple sclerosis, and amyotrophic lateral sclerosis are severe and life-threatening conditions in which significant damage of functional neurons occurs to produce psycho-motor malfunctions. NDs are an important cause of death in the elderly population worldwide. These disorders are commonly associated with the progression of age, oxidative stress, and environmental pollutants, which are the major etiological factors. Abnormal aggregation of specific proteins such as α-synuclein, amyloid-β, huntingtin, and tau, and accumulation of the associated oligomers in neurons are the hallmark pathological features of NDs. Existing therapeutic options for NDs are only symptomatic relief and do not address root-causing factors, such as protein aggregation, oxidative stress, and neuroinflammation. Cannabidiol (CBD) is a non-psychotic natural cannabinoid obtained from Cannabis sativa that possesses multiple pharmacological actions, including antioxidant, anti-inflammatory, and neuroprotective effects in various NDs and other neurological disorders both in vitro and in vivo. CBD has gained attention as a promising drug candidate for the management of neurodegenerative disorders, such as Alzheimer's disease and Parkinson's disease, by inhibiting protein aggregation, free radicals, and neuroinflammation. In parallel, CBD has shown positive results in other neurological disorders, such as epilepsy, depression, schizophrenia, and anxiety, as well as adjuvant treatment with existing standard therapeutic agents. Hence, the present review focuses on exploring the possible molecular mechanisms in controlling various neurological disorders as well as the clinical applications of CBD in NDs including epilepsy, depression and anxiety. In this way, the current review will serve as a standalone reference for the researchers working in this area.

Taming neuroinflammation in Alzheimer's disease: The protective role of phytochemicals through the gut-brain axis

Alzheimer's disease (AD) is a progressive degenerative neurological condition characterized by cognitive decline, primarily affecting memory and logical thinking, attributed to amyloid-β plaques and tau protein tangles in the brain, leading to neuronal loss and brain atrophy. Neuroinflammation, a hallmark of AD, involves the activation of microglia and astrocytes in response to pathological changes, potentially exacerbating neuronal damage. The gut-brain axis is a bidirectional communication pathway between the gastrointestinal and central nervous systems, crucial for maintaining brain health. Phytochemicals, natural compounds found in plants with antioxidant and anti-inflammatory properties, such as flavonoids, curcumin, resveratrol, and quercetin, have emerged as potential modulators of this axis, suggesting implications for AD prevention. Intake of phytochemicals influences the gut microbial composition and its metabolites, thereby impacting neuroinflammation and oxidative stress in the brain. Consumption of phytochemical-rich foods may promote a healthy gut microbiota, fostering the production of anti-inflammatory and neuroprotective substances. Early dietary incorporation of phytochemicals offers a non-invasive strategy for modulating the gut-brain axis and potentially reducing AD risk or delaying its onset. The exploration of interventions targeting the gut-brain axis through phytochemical intake represents a promising avenue for the development of preventive or therapeutic strategies against AD initiation and progression.

Ferroptosis: A new strategy for targeting Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by a complex pathogenesis, which involves the formation of amyloid plaques and neurofibrillary tangles. Many recent studies have revealed a close association between ferroptosis and the pathogenesis of AD. Factors such as ferroptosis-associated iron overload, lipid peroxidation, disturbances in redox homeostasis, and accumulation of reactive oxygen species have been found to contribute to the pathological progression of AD. In this review, we explore the mechanisms underlying ferroptosis, describe the link between ferroptosis and AD, and examine the reported efficacy of ferroptosis inhibitors in treating AD. Finally, we discuss the potential challenges to ferroptosis inhibitors use in the clinic, enabling their faster use in clinical treatment.

The reciprocal relationship between amyloid precursor protein and mitochondrial function

Amyloid precursor protein (APP), secretase enzymes, and amyloid beta (Aβ) have been extensively studied in the context of Alzheimer's disease (AD). Despite this, the function of these proteins and their metabolism is not understood. APP, secretase enzymes, and APP processing products (Aβ and C-terminal fragments) localize to endosomes, mitochondria, endoplasmic reticulum (ER), and mitochondrial/ER contact sites. Studies implicate significant relationships between APP, secretase enzyme function, APP metabolism, and mitochondrial function. Mitochondrial dysfunction is a key pathological hallmark of AD and is intricately linked to proteostasis. Here, we review studies examining potential functions of APP, secretase enzymes, and APP metabolites in the context of mitochondrial function and bioenergetics. We discuss implications and limitations of studies and highlight knowledge gaps that remain in the field.

Does hazelnut consumption affect brain health and function against neurodegenerative diseases?

INTRODUCTION

A healthy daily diet and consuming certain nutrients, such as polyphenols, vitamins, and unsaturated fatty acids, may help neuronal health maintenance. Polyphenolic chemicals, which have antioxidant and anti-inflammatory properties, are involved in the neuroprotective pathway. Because of their nutritional value, nuts have been shown in recent research to be helpful in neuroprotection.

OBJECTIVE

Hazelnut is often consumed worldwide in various items, including processed foods, particularly in bakery, chocolate, and confectionery products. This nut is an excellent source of vitamins, amino acids, tocopherols, phytosterols, polyphenols, minerals, and unsaturated fatty acids. Consuming hazelnut may attenuate the risk of neurodegenerative disorders including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis, and Huntington's disease due to its anti-inflammatory and anti-oxidant qualities.

RESULTS

Many documents introduce hazelnut as an excellent choice to provide neuroprotection against neurodegenerative disorders and there is some direct proof of its neuroprotective effects.

DISCUSSION

So hazelnut consumption in daily diet may reduce neurodegenerative disease risk and be advantageous in reducing the imposed costs of dealing with neurodegenerative diseases.

Proteostasis disruption and senescence in Alzheimer's disease pathways to neurodegeneration

Alzheimer's Disease (AD) is a progressive neurological disease associated with behavioral abnormalities, memory loss, and cognitive impairment that cause major causes of dementia in the elderly. The pathogenetic processes cause complex effects on brain function and AD progression. The proper protein homeostasis, or proteostasis, is critical for cell health. AD causes the buildup of misfolded proteins, particularly tau and amyloid-beta, to break down proteostasis, such aggregates are toxic to neurons and play a critical role in AD pathogenesis. The rise of cellular senescence is accompanied by aging, marked by irreversible cell cycle arrest and the release of pro-inflammatory proteins. Senescent cell build-up in the brains of AD patients exacerbates neuroinflammation and neuronal degeneration. These cells senescence-associated secretory phenotype (SASP) also disturbs the brain environment. When proteostasis failure and cellular senescence coalesce, a cycle is generated that compounds each other. While senescent cells contribute to proteostasis breakdown through inflammatory and degradative processes, misfolded proteins induce cellular stress and senescence. The principal aspects of the neurodegenerative processes in AD are the interaction of cellular senescence and proteostasis failure. This review explores the interconnected roles of proteostasis disruption and cellular senescence in the pathways leading to neurodegeneration in AD.

Biological function of Aβ peptides revealed by analysis of membrane-association properties: Implications for Azheimer's disease pathogenesis

Proteolytic processing of amyloid precursor protein (APP) plays a critical role in the pathogenesis of Azheimer's disease (AD). Sequential cleavage of APP by β and γ secretases leads to generation of Aβ40 (non-amyloidogenic) and Aβ42 (amyloidogenic) peptides. Despite intense studies, the biological function of these peptides and the mechanism of Aβ42 toxicity is poorly understood. In the previous publications we proposed that association of Aβ peptides with the endosomal membranes may have important implications for pathogenesis of AD (Kim and Bezprozvanny, IJMS, 2021, vol 22, 13600; Kim and Bezprozvanny, IJMS, 2023, vol 24, 2092). To understand potential biological importance of such interaction, we focused on the region of Aβ peptides involved in peri-membrane association (E682 to N698). We discovered that association of this region with the membranes is reminiscent of several known anti-microbial peptides (AMP) such as PA13, Aurein1.2 and BP100. Our analysis further revealed that energy of peri-membrane association of Aβ40 is significantly weaker than for Aβ42 or AMP peptides, but it can be increased in the presence of non-amyloidogenic FAD mutations or in the presence of cholesterol in the membrane. Based on similarity with established mechanism of action of AMP peptides, we propose that Aβ peptides affect the curvature of endosomal membranes and shift the balance between endosomal recycling to plasma membrane and late endosomal/lysosomal pathway. We further propose that these effects are enhanced as a result of non-amyloidogenic FAD mutations in the sequence of Aβ peptides or in the presence of cholesterol in the membrane. The proposed model provides potential mechanistic explanation to synaptic defects induced by increased levels of Aβ42, by non-amyloidogenic FAD mutations in APP and by age-related increase in the levels of cholesterol in the brain.

Recent advances in Alzheimer's disease: Mechanisms, clinical trials and new drug development strategies

Alzheimer's disease (AD) stands as the predominant form of dementia, presenting significant and escalating global challenges. Its etiology is intricate and diverse, stemming from a combination of factors such as aging, genetics, and environment. Our current understanding of AD pathologies involves various hypotheses, such as the cholinergic, amyloid, tau protein, inflammatory, oxidative stress, metal ion, glutamate excitotoxicity, microbiota-gut-brain axis, and abnormal autophagy. Nonetheless, unraveling the interplay among these pathological aspects and pinpointing the primary initiators of AD require further elucidation and validation. In the past decades, most clinical drugs have been discontinued due to limited effectiveness or adverse effects. Presently, available drugs primarily offer symptomatic relief and often accompanied by undesirable side effects. However, recent approvals of aducanumab (1) and lecanemab (2) by the Food and Drug Administration (FDA) present the potential in disrease-modifying effects. Nevertheless, the long-term efficacy and safety of these drugs need further validation. Consequently, the quest for safer and more effective AD drugs persists as a formidable and pressing task. This review discusses the current understanding of AD pathogenesis, advances in diagnostic biomarkers, the latest updates of clinical trials, and emerging technologies for AD drug development. We highlight recent progress in the discovery of selective inhibitors, dual-target inhibitors, allosteric modulators, covalent inhibitors, proteolysis-targeting chimeras (PROTACs), and protein-protein interaction (PPI) modulators. Our goal is to provide insights into the prospective development and clinical application of novel AD drugs.

Network Pharmacology Identifies Intersection Genes of Apigenin and Naringenin in Down Syndrome as Potential Therapeutic Targets

Down Syndrome (DS), characterized by trisomy of chromosome 21, leads to the overexpression of several genes contributing to various pathologies, including cognitive deficits and early-onset Alzheimer's disease. This study aimed to identify the intersection genes of two polyphenolic compounds, apigenin and naringenin, and their potential therapeutic targets in DS using network pharmacology. Key proteins implicated in DS, comprising DYRK1A, APP, CBS, and ETS2, were selected for molecular docking and dynamics simulations to assess the binding affinities and stability of the protein-ligand interactions. Molecular docking revealed that naringenin exhibited the highest binding affinity to DYRK1A with a score of -9.3 kcal/mol, followed by CBS, APP, and ETS2. Moreover, molecular docking studies included positive control drugs, such as lamellarin D, valiltramiprosate, benserazide, and TK216, which exhibited binding affinities ranging from -5.5 to -8.9 kcal/mol. Apigenin showed strong binding to APP with a score of -8.8 kcal/mol, suggesting its potential in modulating amyloid-beta levels. These interactions were further validated through molecular dynamics simulations, demonstrating stable binding throughout the 100 ns simulation period. Root mean square deviation (RMSD) and root mean square fluctuation (RMSF) analyses indicated minimal fluctuations, confirming the stability of the complexes. The findings suggest that apigenin and naringenin could serve as effective therapeutic agents for DS by targeting key proteins involved in its pathology. Future studies should focus on in vivo validation, clinical trials, and exploring combination therapies to fully harness the therapeutic potential of these compounds for managing DS. This study underscores the promising role of network pharmacology in identifying novel therapeutic targets and agents for complex disorders like DS.

Glycosylation in aging and neurodegenerative diseases

Aging, a complex biological process, involves the progressive decline of physiological functions across various systems, leading to increased susceptibility to neurodegenerative diseases. In society, demographic aging imposes significant economic and social burdens due to these conditions. This review specifically examines the association of protein glycosylation with aging and neurodegenerative diseases. Glycosylation, a critical post-translational modification, influences numerous aspects of protein function that are pivotal in aging and the pathophysiology of diseases such as Alzheimer's disease, Parkinson's disease, and other neurodegenerative conditions. We highlight the alterations in glycosylation patterns observed during aging, their implications in the onset and progression of neurodegenerative diseases, and the potential of glycosylation profiles as biomarkers for early detection, prognosis, and monitoring of these age-associated conditions, and delve into the mechanisms of glycosylation. Furthermore, this review explores their role in regulating protein function and mediating critical biological interactions in these diseases. By examining the changes in glycosylation profiles associated with each part, this review underscores the potential of glycosylation research as a tool to enhance our understanding of aging and its related diseases.

m5C RNA methylation: a potential mechanism for infectious Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disorder caused by a variety of factors, including age, genetic susceptibility, cardiovascular disease, traumatic brain injury, and environmental factors. The pathogenesis of AD is largely associated with the overproduction and accumulation of amyloid-β peptides and the hyperphosphorylation of tau protein in the brain. Recent studies have identified the presence of diverse pathogens, including viruses, bacteria, and parasites, in the tissues of AD patients, underscoring the critical role of central nervous system infections in inducing pathological changes associated with AD. Nevertheless, it remains unestablished about the specific mechanism by which infections lead to the occurrence of AD. As an important post-transcriptional RNA modification, RNA 5-methylcytosine (m5C) methylation regulates a wide range of biological processes, including RNA splicing, nuclear export, stability, and translation, therefore affecting cellular function. Moreover, it has been recently demonstrated that multiple pathogenic microbial infections are associated with the m5C methylation of the host. However, the role of m5C methylation in infectious AD is still uncertain. Therefore, this review discusses the mechanisms of pathogen-induced AD and summarizes research on the molecular mechanisms of m5C methylation in infectious AD, thereby providing new insight into exploring the mechanism underlying infectious AD.

Fluorescent Peptides Sequester Redox Copper to Mitigate Oxidative Stress, Amyloid Toxicity, and Neuroinflammation

Alzheimer's disease is a progressive neurodegenerative disorder that significantly contributes to dementia. The lack of effective therapeutic interventions presents a significant challenge to global health. We have developed a set of short peptides (PNGln) conjugated with a dual-functional fluorophoric amino acid (NGln). The lead peptide, P2NGln, displays a high affinity for Cu2+, maintaining the metal ion in a redox-inactive state. This mitigates the cytotoxicity generated by reactive oxygen species (ROS), which are produced by Cu2+ under the reductive conditions of Asc and Aβ16 or Aβ42. Furthermore, P2NGln inhibits both Cu-dependent and -independent fibrillation of Aβ42, along with the subsequent toxicity induced by Aβ42. In addition, P2NGln exhibits inhibitory effects on the production of lipopolysaccharide (LPS)-induced ROS and reactive nitrogen species (RNS) in microglial cells. In vitro and cellular studies indicate that P2NGln could significantly reduce Aβ-Cu2+-induced ROS production, amyloid toxicity, and neuroinflammation, offering an innovative strategy against Alzheimer's disease.

MRI-based quantification of cardiac-driven brain biomechanics for early detection of neurological disorders

We present a pipeline to quantify biomechanical environment of the brain using solely MRI-derived data in order to elucidate the role of biomechanical factors in neurodegenerative disorders. Neurological disorders, like Alzheimer's and Parkinson's diseases, are associated with physical changes, including the accumulation of amyloid-β and tau proteins, damage to the cerebral vasculature, hypertension, atrophy of the cortical gray matter, and lesions of the periventricular white matter. Alterations in the external mechanical environment of cells can trigger pathological processes, and it is known that AD causes reduced stiffness in the brain tissue during degeneration. However, there appears to be a significant lag time between microscale changes and macroscale obstruction of neurological function in the brain. Here, we present a pipeline to quantify the whole brain biomechanical environment to bridge the gap in understanding how underlying brain changes affect macroscale brain biomechanics. This pipeline enables image-based quantification of subject-specific displacement field of the whole brain to subject-specific strain, strain rate, and stress across 133 labeled functional brain regions. We have focused our development efforts on utilizing solely MRI-derived data to facilitate clinical applicability of our approach and have emphasized automation in all aspects of our methods to reduce operator dependance. Our pipeline has the potential to improve early detection of neurological disorders and facilitate the identification of disease before widespread, irreversible damage has occurred.

Brain-Gut and Microbiota-Gut-Brain Communication in Type-2 Diabetes Linked Alzheimer's Disease

The gastrointestinal (GI) tract, home to the largest microbial population in the human body, plays a crucial role in overall health through various mechanisms. Recent advancements in research have revealed the potential implications of gut-brain and vice-versa communication mediated by gut-microbiota and their microbial products in various diseases including type-2 diabetes and Alzheimer's disease (AD). AD is the most common type of dementia where most of cases are sporadic with no clearly identified cause. However, multiple factors are implicated in the progression of sporadic AD which can be classified as non-modifiable (e.g., genetic) and modifiable (e.g. Type-2 diabetes, diet etc.). Present review focusses on key players particularly the modifiable factors such as Type-2 diabetes (T2D) and diet and their implications in microbiota-gut-brain (MGB) and brain-gut (BG) communication and cognitive functions of healthy brain and their dysfunction in Alzheimer's Disease. Special emphasis has been given on elucidation of the mechanistic aspects of the impact of diet on gut-microbiota and the implications of some of the gut-microbial products in T2D and AD pathology. For example, mechanistically, HFD induces gut dysbiosis with driven metabolites that in turn cause loss of integrity of intestinal barrier with concomitant colonic and systemic chronic low-grade inflammation, associated with obesity and T2D. HFD-induced obesity and T2D parallel neuroinflammation, deposition of Amyloid β (Aβ), and ultimately cognitive impairment. The review also provides a new perspective of the impact of diet on brain-gut and microbiota-gut-brain communication in terms of transcription factors as a commonly spoken language that may facilitates the interaction between gut and brain of obese diabetic patients who are at a higher risk of developing cognitive impairment and AD. Other commonality such as tyrosine kinase expression and functions maintaining intestinal integrity on one hand and the phagocytic clarence by migratory microglial functions in brain are also discussed. Lastly, the characterization of the key players future research that might shed lights on novel potential pharmacological target to impede AD progression are also discussed.

Mutation of TRPML1 Channel and Pathogenesis of Neurodegeneration in Haimeria

Neurodegenerative diseases, a group of debilitating disorders, have garnered increasing attention due to their escalating prevalence, particularly among aging populations. Alzheimer's disease (AD) reigns as a prominent exemplar within this category, distinguished by its relentless progression of cognitive impairment and the accumulation of aberrant protein aggregates within the intricate landscape of the brain. While the intricate pathogenesis of neurodegenerative diseases has been the subject of extensive investigation, recent scientific inquiry has unveiled a novel player in this complex scenario-transient receptor potential mucolipin 1 (TRPML1) channels. This comprehensive review embarks on an exploration of the intricate interplay between TRPML1 channels and neurodegenerative diseases, with an explicit spotlight on Alzheimer's disease. It immerses itself in the intricate molecular mechanisms governing TRPML1 channel functionality and elucidates their profound implications for the well-being of neurons. Furthermore, the review ventures into the realm of therapeutic potential, pondering the possibilities and challenges associated with targeting TRPML1 channels as a promising avenue for the amelioration of neurodegenerative disorders. As we traverse this multifaceted terrain of neurodegeneration and the enigmatic role of TRPML1 channels, we embark on a journey that not only broadens our understanding of the intricate machinery governing neuronal health but also holds promise for the development of innovative therapeutic interventions in the relentless battle against neurodegenerative diseases.

Mitochondria in Aging and Alzheimer's Disease: Focus on Mitophagy

Alzheimer's disease (AD) is characterized by the accumulation of amyloid β and phosphorylated τ protein aggregates in the brain, which leads to the loss of neurons. Under the microscope, the function of mitochondria is uniquely primed to play a pivotal role in neuronal cell survival, energy metabolism, and cell death. Research studies indicate that mitochondrial dysfunction, excessive oxidative damage, and defective mitophagy in neurons are early indicators of AD. This review article summarizes the latest development of mitochondria in AD: 1) disease mechanism pathways, 2) the importance of mitochondria in neuronal functions, 3) metabolic pathways and functions, 4) the link between mitochondrial dysfunction and mitophagy mechanisms in AD, and 5) the development of potential mitochondrial-targeted therapeutics and interventions to treat patients with AD.

MGST3 regulates BACE1 protein translation and amyloidogenesis by controlling the RGS4-mediated AKT signaling pathway

Microsomal glutathione transferase 3 (MGST3) regulates eicosanoid and glutathione metabolism. These processes are associated with oxidative stress and apoptosis, suggesting that MGST3 might play a role in the pathophysiology of Alzheimer's disease. Here, we report that knockdown (KD) of MGST3 in cell lines reduced the protein level of beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) and the resulting amyloidogenesis. Interestingly, MGST3 KD did not alter intracellular reactive oxygen species level but selectively reduced the expression of apoptosis indicators which could be associated with the receptor of cysteinyl leukotrienes, the downstream metabolites of MGST3 in arachidonic acid pathway. We then showed that the effect of MGST3 on BACE1 was independent of cysteinyl leukotrienes but involved a translational mechanism. Further RNA-seq analysis identified that regulator of G-protein signaling 4 (RGS4) was a target gene of MGST3. Silencing of RGS4 inhibited BACE1 translation and prevented MGST3 KD-mediated reduction of BACE1. The potential mechanism was related to AKT activity, as the protein level of phosphorylated AKT was significantly reduced by silencing of MGST3 and RGS4, and the AKT inhibitor abolished the effect of MGST3/RGS4 on phosphorylated AKT and BACE1. Together, MGST3 regulated amyloidogenesis by controlling BACE1 protein expression, which was mediated by RGS4 and downstream AKT signaling pathway.

Eta-secretase-like processing of the amyloid precursor protein (APP) by the rhomboid protease RHBDL4

The amyloid precursor protein (APP) is a key protein in Alzheimer's disease synthesized in the endoplasmic reticulum (ER) and translocated to the plasma membrane where it undergoes proteolytic cleavages by several proteases. Conversely, to other known proteases, we previously elucidated rhomboid protease RHBDL4 as a novel APP processing enzyme where several cleavages likely occur already in the ER. Interestingly, the pattern of RHBDL4-derived large APP C-terminal fragments resembles those generated by the η-secretase or MT5-MMP, which was described to generate so-called Aη fragments. The similarity in large APP C-terminal fragments between both proteases raised the question of whether RHBDL4 may contribute to η-secretase activity and Aη-like fragments. Here, we identified two cleavage sites of RHBDL4 in APP by mass spectrometry, which, intriguingly, lie in close proximity to the MT5-MMP cleavage sites. Indeed, we observed that RHBDL4 generates Aη-like fragments in vitro without contributions of α-, β-, or γ-secretases. Such Aη-like fragments are likely generated in the ER since RHBDL4-derived APP-C-terminal fragments do not reach the cell surface. Inherited, familial APP mutations appear to not affect this processing pathway. In RHBDL4 knockout mice, we observed increased cerebral full-length APP in comparison to wild type (WT) in support of RHBDL4 being a physiologically relevant protease for APP. Furthermore, we found secreted Aη fragments in dissociated mixed cortical cultures from WT mice, however significantly fewer Aη fragments in RHBDL4 knockout cultures. Our data underscores that RHBDL4 contributes to the η-secretease-like processing of APP and that RHBDL4 is a physiologically relevant protease for APP.

Microglia and Astrocytes in Alzheimer's Disease: Significance and Summary of Recent Advances

Alzheimer's disease, one of the most common forms of dementia, is characterized by a slow progression of cognitive impairment and neuronal loss. Currently, approved treatments for AD are hindered by various side effects and limited efficacy. Despite considerable research, practical treatments for AD have not been developed. Increasing evidence shows that glial cells, especially microglia and astrocytes, are essential in the initiation and progression of AD. During AD progression, activated resident microglia increases the ability of resting astrocytes to transform into reactive astrocytes, promoting neurodegeneration. Extensive clinical and molecular studies show the involvement of microglia and astrocyte-mediated neuroinflammation in AD pathology, indicating that microglia and astrocytes may be potential therapeutic targets for AD. This review will summarize the significant and recent advances of microglia and astrocytes in the pathogenesis of AD in three parts. First, we will review the typical pathological changes of AD and discuss microglia and astrocytes in terms of function and phenotypic changes. Second, we will describe microglia and astrocytes' physiological and pathological role in AD. These roles include the inflammatory response, "eat me" and "don't eat me" signals, Aβ seeding, propagation, clearance, synapse loss, synaptic pruning, remyelination, and demyelination. Last, we will review the pharmacological and non-pharmacological therapies targeting microglia and astrocytes in AD. We conclude that microglia and astrocytes are essential in the initiation and development of AD. Therefore, understanding the new role of microglia and astrocytes in AD progression is critical for future AD studies and clinical trials. Moreover, pharmacological, and non-pharmacological therapies targeting microglia and astrocytes, with specific studies investigating microglia and astrocyte-mediated neuronal damage and repair, may be a promising research direction for future studies regarding AD treatment and prevention.

Elucidating the therapeutic mechanism of betanin in Alzheimer's Disease treatment through network pharmacology and bioinformatics analysis

Betanin, a natural compound with anti-inflammatory and antioxidant properties, has shown promise in mitigating Alzheimer's disease (AD) by reducing amyloid plaque production. Employing network pharmacology, this study aimed to elucidate betanin's therapeutic mechanism in AD treatment. Through integrated analyses utilizing SwissTargetPrediction, STITCH, BindingDB, Therapeutic Target Database (TTD), and OMIM databases, potential protein targets of betanin in AD were predicted. Gene ontology analysis facilitated the identification of 49 putative AD targets. Subsequent gene enrichment and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway analysis revealed associations between these targets and AD. Network pharmacology techniques and molecular docking aided in prioritizing essential genes, with APP, CASP7, ITPR1, CASP8, CASP3, ITPR3, and NF-KB1 emerging as top candidates. The results provide novel insights into betanin's therapeutic efficacy, shedding light on its potential clinical application in AD treatment. By targeting key genes implicated in AD pathology, betanin demonstrates promise as a valuable addition to existing therapeutic strategies. This holistic approach emphasizes the relevance of network pharmacology and bioinformatics analysis in understanding natural chemical disease therapy processes.

Insights into Dysregulated Neurological Biomarkers in Cancer

The link between neurodegenerative diseases (NDs) and cancer has generated greater interest in biomedical research, with decades of global studies investigating neurodegenerative biomarkers in cancer to better understand possible connections. Tau, amyloid-β, α-synuclein, SOD1, TDP-43, and other proteins associated with nervous system diseases have also been identified in various types of solid and malignant tumors, suggesting a potential overlap in pathological processes. In this review, we aim to provide an overview of current evidence on the role of these proteins in cancer, specifically examining their effects on cell proliferation, apoptosis, chemoresistance, and tumor progression. Additionally, we discuss the diagnostic and therapeutic implications of this interconnection, emphasizing the importance of further research to completely comprehend the clinical implications of these proteins in tumors. Finally, we explore the challenges and opportunities in targeting these proteins for the development of new targeted anticancer therapies, providing insight into how to integrate knowledge of NDs in oncology research.

Linking coronary artery disease to neurodegenerative diseases through systems genetics

Coronary artery disease (CAD) is still a leading cause of death worldwide despite the extensive research and the considerable progresses made through the years. As other cardiovascular diseases, CAD is the result of the complex interaction between genetic variants and environmental factors. Currently identified genetic loci associated to CAD revealed the contribution of multiple molecular pathways to its pathogenesis, suggesting the need for a systemic approach to understand the role of genetic determinants. In this study we wanted to investigate how GWAS variants associated to CAD interact with each other and with nearby genes in the context of the coronary artery molecular interactome. GWAS variants associated to CAD were selected from GWAS Catalog, then, a tissue-specific interactome was constructed integrating protein-protein interactions (PPI) from multiple public repositories and computationally inferred co-expression relationships. To focus on the part of the network most relevant for CAD, we selected the interactions connecting the genes carrying a variant associated to the disease. A functional enrichment analysis conducted on the subnetwork revealed that genes carrying genetic variants associated to CAD closely interact with genes related to relevant biological processes, such as extracellular matrix organization, lipoprotein clearance, arterial morphology and inflammatory response. These results confirm that the identified subnetwork reflects the molecular pathways altered in CAD and intercepted by the selected variants. Interestingly, the most connected nodes of the network included amyloid beta precursor protein (APP) and huntingtin (HTT), both implicated in neurodegenerative disorders. In recent years the interest in investigating the common processes between cardiovascular diseases and neurodegenerative disorders is increasing, with growing evidence of a link between CAD and Alzheimer's disease. The results obtained in this work support the association between such apparently unrelated diseases and highlight the necessity of a systems biology approach to better elucidate shared pathological mechanisms.

Energetic portrait of the amyloid beta nucleation transition state

Amyloid protein aggregates are pathological hallmarks of more than fifty human diseases including the most common neurodegenerative disorders. The atomic structures of amyloid fibrils have now been determined, but the process by which soluble proteins nucleate to form amyloids remains poorly characterised and difficult to study, even though this is the key step to understand to prevent the formation and spread of aggregates. Here we use massively parallel combinatorial mutagenesis, a kinetic selection assay, and machine learning to reveal the transition state of the nucleation reaction of amyloid beta, the protein that aggregates in Alzheimer's disease. By quantifying the nucleation of >140,000 proteins we infer the changes in activation energy for all 798 amino acid substitutions in amyloid beta and the energetic couplings between >600 pairs of mutations. This unprecedented dataset provides the first comprehensive view of the energy landscape and the first large-scale measurement of energetic couplings for a protein transition state. The energy landscape reveals that the amyloid beta nucleation transition state contains a short structured C-terminal hydrophobic core with a subset of interactions similar to mature fibrils. This study demonstrates the feasibility of using mutation-selection-sequencing experiments to study transition states and identifies the key molecular species that initiates amyloid beta aggregation and, potentially, Alzheimer's disease.

Gestational physical activity alters offspring brain APP processing in an age-specific manner

Maternal exercise is beneficial for offspring brain development. Amyloid precursor protein (APP) influences neurogenesis and synaptic plasticity. Cleavage products of APP are implicated in the proliferation of neural progenitor cells and neuronal network development. Our study aimed to investigate differences in APP processing in active or sedentary offspring of dams who were exposed to voluntary wheel running with and without a western diet throughout gestation. Female Wistar rats (7-8 weeks old) were fed a normal chow or western diet and randomized into voluntary wheel run or sedentary conditions. Dams returned to sedentary conditions post-parturition. The pups were weaned at 6 weeks after which point half of the samples were collected, while the rest of the pups remained on a normal diet, separated into sedentary or voluntary wheel run groups, and collected 12 weeks later. In utero exposure to maternal exercise was associated with higher neuronal nuclear protein, higher soluble APPα and lower soluble APPβ in offspring prefrontal cortex tissue at 6, but not 18 weeks of age. Neuronal nuclear protein is exclusive to mature neurons implying that offspring of mothers who exercised could have more neuron maturation potentially influenced by the higher APPα content at this early developmental stage. The voluntary wheel run offspring groups had a higher mature/pro brain derived neurotrophic factor ratio compared to the sedentary counterparts. The maternal effects were isolated to the juvenile 6-week-old pups, while the differences in the adult offspring were caused by their own exercise status.

SIL1 improves cognitive impairment in APP23/PS45 mice by regulating amyloid precursor protein processing and Aβ generation

SIL1, an endoplasmic reticulum (ER)-resident protein, is reported to play a protective role in Alzheimer's disease (AD). However, the effect of SIL1 on amyloid precursor protein (APP) processing remains unclear. In this study, the role of SIL1 in APP processing was explored both in vitro and in vivo. In the in vitro experiment, SIL1 was either overexpressed or knocked down in cells stably expressing the human Swedish mutant APP695. In the in vivo experiment, AAV-SIL1-EGFP or AAV-EGFP was microinjected into APP23/PS45 mice and their wild-type littermates. Western blotting (WB), immunohistochemistry, RNA sequencing (RNA-seq), and behavioral experiments were performed to evaluate the relevant parameters. Results indicated that SIL1 expression decreased in APP23/PS45 mice. Overexpression of SIL1 significantly decreased the protein levels of APP, presenilin-1 (PS1), and C-terminal fragments (CTFs) of APP in vivo and in vitro. Conversely, knockdown of SIL1 increased the protein levels of APP, β-site APP cleavage enzyme 1 (BACE1), PS1, and CTFs, as well as APP mRNA expression in 2EB2 cells. Furthermore, SIL1 overexpression reduced the number of senile plaques in APP23/PS45 mice. Importantly, Y-maze and Morris Water maze tests demonstrated that SIL1 overexpression improved cognitive impairment in APP23/PS45 mice. These findings indicate that SIL1 improves cognitive impairment in APP23/PS45 mice by inhibiting APP amyloidogenic processing and suggest that SIL1 is a potential therapeutic target for AD by modulating APP processing.

The duality of amyloid-β: its role in normal and Alzheimer's disease states

Alzheimer's disease (AD) is a degenerative neurological condition that gradually impairs cognitive abilities, disrupts memory retention, and impedes daily functioning by impacting the cells of the brain. A key characteristic of AD is the accumulation of amyloid-beta (Aβ) plaques, which play pivotal roles in disease progression. These plaques initiate a cascade of events including neuroinflammation, synaptic dysfunction, tau pathology, oxidative stress, impaired protein clearance, mitochondrial dysfunction, and disrupted calcium homeostasis. Aβ accumulation is also closely associated with other hallmark features of AD, underscoring its significance. Aβ is generated through cleavage of the amyloid precursor protein (APP) and plays a dual role depending on its processing pathway. The non-amyloidogenic pathway reduces Aβ production and has neuroprotective and anti-inflammatory effects, whereas the amyloidogenic pathway leads to the production of Aβ peptides, including Aβ40 and Aβ42, which contribute to neurodegeneration and toxic effects in AD. Understanding the multifaceted role of Aβ, particularly in AD, is crucial for developing effective therapeutic strategies that target Aβ metabolism, aggregation, and clearance with the aim of mitigating the detrimental consequences of the disease. This review aims to explore the mechanisms and functions of Aβ under normal and abnormal conditions, particularly in AD, by examining both its beneficial and detrimental effects.

Huperzine A Regulates the Physiological Homeostasis of Amyloid Precursor Protein Proteolysis and Tau Protein Conformation-A Computational and Experimental Investigation

The beneficial actions of the natural compound Huperzine A (Hup A) against age-associated learning and memory deficits promote this compound as a nootropic agent. Alzheimer's disease (AD) pathophysiology is characterized by the accumulation of amyloid beta (Aβ). Toxic Aβ oligomers account for the cognitive dysfunctions much before the pathological lesions are manifested in the brain. In the present study, we investigated the effects of Hup A on amyloid precursor protein (APP) proteolysis in SH-SY5Y neuroblastoma cells. Hup A downregulated the expression of β-site amyloid precursor protein cleaving enzyme 1 (BACE1) and presenilin 1 (PS1) levels but augmented the levels of A disintegrin and metalloproteinase 10 (ADAM10) with significant decrement in the Aβ levels. We herein report for the first time an in silico molecular docking analysis that revealed that Hup A binds to the functionally active site of BACE1. We further analyzed the effect of Hup A on glycogen synthase kinase-3 β (GSK3β) and phosphorylation status of tau. In this scenario, based on the current observations, we propose that Hup A is a potent regulator of APP processing and capable of modulating tau homeostasis under physiological conditions holding immense potential in preventing and treating AD like disorders.

Molecular mechanisms and therapeutic potential of lithium in Alzheimer's disease: repurposing an old class of drugs

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline and memory loss. Despite advances in understanding the pathophysiological mechanisms of AD, effective treatments remain scarce. Lithium salts, recognized as mood stabilizers in bipolar disorder, have been extensively studied for their neuroprotective effects. Several studies indicate that lithium may be a disease-modifying agent in the treatment of AD. Lithium's neuroprotective properties in AD by acting on multiple neuropathological targets, such as reducing amyloid deposition and tau phosphorylation, enhancing autophagy, neurogenesis, and synaptic plasticity, regulating cholinergic and glucose metabolism, inhibiting neuroinflammation, oxidative stress, and apoptosis, while preserving mitochondrial function. Clinical trials have demonstrated that lithium therapy can improve cognitive function in patients with AD. In particular, meta-analyses have shown that lithium may be a more effective and safer treatment than the recently FDA-approved aducanumab for improving cognitive function in patients with AD. The affordability and therapeutic efficacy of lithium have prompted a reassessment of its use. However, the use of lithium may lead to potential side effects and safety issues, which may limit its clinical application. Currently, several new lithium formulations are undergoing clinical trials to improve safety and efficacy. This review focuses on lithium's mechanism of action in treating AD, highlighting the latest advances in preclinical studies and clinical trials. It also explores the side effects of lithium therapy and coping strategies, offering a potential therapeutic strategy for patients with AD.

Single-Cell RNA Sequencing Reveals Immunomodulatory Effects of Stem Cell Factor and Granulocyte Colony-Stimulating Factor Treatment in the Brains of Aged APP/PS1 Mice

Alzheimer's disease (AD) leads to progressive neurodegeneration and dementia. AD primarily affects older adults with neuropathological changes including amyloid-beta (Aβ) deposition, neuroinflammation, and neurodegeneration. We have previously demonstrated that systemic treatment with combined stem cell factor (SCF) and granulocyte colony-stimulating factor (G-CSF) (SCF+G-CSF) reduces the Aβ load, increases Aβ uptake by activated microglia and macrophages, reduces neuroinflammation, and restores dendrites and synapses in the brains of aged APPswe/PS1dE9 (APP/PS1) mice. However, the mechanisms underlying SCF+G-CSF-enhanced brain repair in aged APP/PS1 mice remain unclear. This study used a transcriptomic approach to identify the potential mechanisms by which SCF+G-CSF treatment modulates microglia and peripheral myeloid cells to mitigate AD pathology in the aged brain. After injections of SCF+G-CSF for 5 consecutive days, single-cell RNA sequencing was performed on CD11b+ cells isolated from the brains of 28-month-old APP/PS1 mice. The vast majority of cell clusters aligned with transcriptional profiles of microglia in various activation states. However, SCF+G-CSF treatment dramatically increased a cell population showing upregulation of marker genes related to peripheral myeloid cells. Flow cytometry data also revealed an SCF+G-CSF-induced increase of cerebral CD45high/CD11b+ active phagocytes. SCF+G-CSF treatment robustly increased the transcription of genes implicated in immune cell activation, including gene sets that regulate inflammatory processes and cell migration. The expression of S100a8 and S100a9 was robustly enhanced following SCF+G-CSF treatment in all CD11b+ cell clusters. Moreover, the topmost genes differentially expressed with SCF+G-CSF treatment were largely upregulated in S100a8/9-positive cells, suggesting a well-conserved transcriptional profile related to SCF+G-CSF treatment in resident and peripherally derived CD11b+ immune cells. This S100a8/9-associated transcriptional profile contained notable genes related to pro-inflammatory and anti-inflammatory responses, neuroprotection, and Aβ plaque inhibition or clearance. Altogether, this study reveals the immunomodulatory effects of SCF+G-CSF treatment in the aged brain with AD pathology, which will guide future studies to further uncover the therapeutic mechanisms.

The Effects of Sevoflurane and Aβ Interaction on CA1 Dendritic Spine Dynamics and MEGF10-Related Astrocytic Synapse Engulfment

General anesthetics may accelerate the neuropathological changes related to Alzheimer's disease (AD), of which amyloid beta (Aβ)-induced toxicity is one of the main causes. However, the interaction of general anesthetics with different Aβ-isoforms remains unclear. In this study, we investigated the effects of sevoflurane (0.4 and 1.2 maximal alveolar concentration (MAC)) on four Aβ species-induced changes on dendritic spine density (DSD) in hippocampal brain slices of Thy1-eGFP mice and multiple epidermal growth factor-like domains 10 (MEGF10)-related astrocyte-mediated synaptic engulfment in hippocampal brain slices of C57BL/6 mice. We found that both sevoflurane and Aβ downregulated CA1-dendritic spines. Moreover, compared with either sevoflurane or Aβ alone, pre-treatment with Aβ isoforms followed by sevoflurane application in general further enhanced spine loss. This enhancement was related to MEGF10-related astrocyte-dependent synaptic engulfment, only in AβpE3 + 1.2 MAC sevoflurane and 3NTyrAβ + 1.2 MAC sevoflurane condition. In addition, removal of sevoflurane alleviated spine loss in Aβ + sevoflurane. In summary, these results suggest that both synapses and astrocytes are sensitive targets for sevoflurane; in the presence of 3NTyrAβ, 1.2 MAC sevoflurane alleviated astrocyte-mediated synaptic engulfment and exerted a lasting effect on dendritic spine remodeling.

ACOT7, a candidate and novel serum biomarker of Alzheimer's disease

Alzheimer's disease (AD) is the most common fatal neurodegenerative disease among the elderly worldwide, characterized by memory and cognitive impairment. The identification of biomarkers for AD is crucial and urgent to facilitate the diagnosis and intervention. The aim of this study was to evaluate the diagnostic value of acyl-Coenzyme A thioesterase 7 (ACOT7) as a serum biomarker for the prediction of AD. In our study, we observed a significant increase in ACOT7 expression in patients (n = 366) with AD and animal (n = 8-12) models of AD, compared to the control group. A significant negative correlation was found between ACOT7 levels and Mini-Mental State Examination (MMSE) scores (r = -0.85; p < 0.001). The analysis of the receiver operating characteristic curve (ROC) showed that the area under the curve (AUC) for ACOT7 was 0.83 (95% confidence intervals: 0.80-0.86). The optimal cut-off point of 62.5 pg./mL was selected with the highest sum of sensitivity and specificity. The diagnostic accuracy of serum ACOT7 for AD was 77% (95% confidence intervals: 72-82%), with a sensitivity of 80% (95% confidence intervals: 75-84%) and a specificity of 74% (95% confidence intervals: 69-79%). Moreover, the ROC analysis showed that the AUC of Aβ42/40 ratio is 0.70, and the diagnostic accuracy was 72%, with 69% sensitivity and 76% specificity. Compared with the AD traditional marker Aβ42/40 ratio, ACOT7 shows better superiority as a new serum candidate biomarker of AD. By suppressing the ACOT7 gene, our study provides evidence of the involvement of ACOT7 in the metabolism of amyloid precursor protein (APP), resulting in alterations in the expression levels of Aβ42, BACE1 and βCTF. ACOT7 has the ability to modulate the amyloidogenic pathway of APP metabolism, while it does not have an impact on the non-amyloidogenic pathway. In conclusion, the findings of our study suggest that serum ACOT7 may serve as a promising and non-invasive biomarker for AD.

Polysaccharides from Basella alba Protect Post-Mitotic Neurons against Cell Cycle Re-Entry and Apoptosis Induced by the Amyloid-Beta Peptide by Blocking Sonic Hedgehog Expression

The amyloid-beta peptide (Aβ) is the neurotoxic component in senile plaques of Alzheimer's disease (AD) brains. Previously we have reported that Aβ toxicity is mediated by the induction of sonic hedgehog (SHH) to trigger cell cycle re-entry (CCR) and apoptosis in post-mitotic neurons. Basella alba is a vegetable whose polysaccharides carry immunomodulatory and anti-cancer actions, but their protective effects against neurodegeneration have never been reported. Herein, we tested whether polysaccharides derived from Basella alba (PPV-6) may inhibit Aβ toxicity and explored its underlying mechanisms. In differentiated rat cortical neurons, Aβ25-35 reduced cell viability, damaged neuronal structure, and compromised mitochondrial bioenergetic functions, all of which were recovered by PPV-6. Immunocytochemistry and western blotting revealed that Aβ25-35-mediated induction of cell cycle markers including cyclin D1, proliferating cell nuclear antigen (PCNA), and histone H3 phosphorylated at Ser-10 (p-Histone H3) in differentiated neurons was all suppressed by PPV-6, along with mitigation of caspase-3 cleavage. Further studies revealed that PPV-6 inhibited Aβ25-35 induction of SHH; indeed, PPV-6 was capable of suppressing neuronal CCR and apoptosis triggered by the exogenous N-terminal fragment of sonic hedgehog (SHH-N). Our findings demonstrated that, in the fully differentiated neurons, PPV-6 exerts protective actions against Aβ neurotoxicity via the downregulation of SHH to suppress neuronal CCR and apoptosis.

Serum and urine metabolomics based on UPLC-QTOF/MS reveal the effect and potential mechanism of "schisandra-evodia" herb pair in the treatment of Alzheimer's disease

The "schisandra-evodia" herb pair (S-E) is a herbal preparation to treat Alzheimer's disease (AD). This study aims to investigate the therapeutic efficacy and potential mechanism of S-E in AD rats, utilizing pharmacodynamic assessments and serum- and urine-based metabolomic analyses. Pharmacodynamic assessments included Morris water maze test, hematoxylin-eosin staining and immunohistochemistry experiments. The results of the study showed that the AD model was successful; the S-E significantly enhanced long-term memory and spatial learning in AD rats. Meanwhile, S-E notably ameliorated Aβ25-35-induced cognitive impairment, improved hippocampal neuron morphology, decreased Aβ deposition in the hippocampus and mitigated inflammatory damage. We then analyzed serum and urine samples using UPLC-MS/MS to identify potential biomarkers and metabolic pathways. Metabolomic analysis revealed alterations in 40 serum metabolites and 38 urine metabolites following S-E treatment, predominantly affecting pathways related to taurine and hypotaurine metabolism, linoleic acid metabolism, α-linolenic acid metabolism, glycerophospholipid metabolism and arachidonic acid metabolism. This study elucidates the biochemical mechanism underlying AD and the metabolic pathway influenced by S-E, laying the groundwork for future clinical applications.

Molecular signatures of premature aging in Major Depression and Substance Use Disorders

Major depressive disorder (MDD) and substance-use disorders (SUDs) often lead to premature aging, increasing vulnerability to cognitive decline and other forms of dementia. This study utilized advanced systems bioinformatics to identify aging "signatures" in MDD and SUDs and evaluated the potential for known lifespan-extending drugs to target and reverse these signatures. The results suggest that inhibiting the transcriptional activation of FOS gene family members holds promise in mitigating premature aging in MDD and SUDs. Conversely, antidepressant drugs activating the PI3K/Akt/mTOR pathway, a common mechanism in rapid-acting antidepressants, may accelerate aging in MDD patients, making them unsuitable for those with comorbid aging-related conditions like dementia and Alzheimer's disease. Additionally, this innovative approach identifies potential anti-aging interventions for MDD patients, such as Deferoxamine, Resveratrol, Estradiol valerate, and natural compounds like zinc acetate, genistein, and ascorbic acid, regardless of comorbid anxiety disorders. These findings illuminate the premature aging effects of MDD and SUDs and offer insights into treatment strategies for patients with comorbid aging-related conditions, including dementia and Alzheimer's disease.

Xenografted human iPSC-derived neurons with the familial Alzheimer's disease APPV717I mutation reveal dysregulated transcriptome signatures linked to synaptic function and implicate LINGO2 as a disease signaling mediator

Alzheimer's disease (AD) is the most common cause of dementia, and disease mechanisms are still not fully understood. Here, we explored pathological changes in human induced pluripotent stem cell (iPSC)-derived neurons carrying the familial AD APPV717I mutation after cell injection into the mouse forebrain. APPV717I mutant iPSCs and isogenic controls were differentiated into neurons revealing enhanced Aβ42 production, elevated phospho-tau, and impaired neurite outgrowth in APPV717I neurons. Two months after transplantation, APPV717I and control neural cells showed robust engraftment but at 12 months post-injection, APPV717I grafts were smaller and demonstrated impaired neurite outgrowth compared to controls, while plaque and tangle pathology were not seen. Single-nucleus RNA-sequencing of micro-dissected grafts, performed 2 months after cell injection, identified significantly altered transcriptome signatures in APPV717I iPSC-derived neurons pointing towards dysregulated synaptic function and axon guidance. Interestingly, APPV717I neurons showed an increased expression of genes, many of which are also upregulated in postmortem neurons of AD patients including the transmembrane protein LINGO2. Downregulation of LINGO2 in cultured APPV717I neurons rescued neurite outgrowth deficits and reversed key AD-associated transcriptional changes related but not limited to synaptic function, apoptosis and cellular senescence. These results provide important insights into transcriptional dysregulation in xenografted APPV717I neurons linked to synaptic function, and they indicate that LINGO2 may represent a potential therapeutic target in AD.

Numerical modeling of senile plaque development under conditions of limited diffusivity of amyloid-β monomers

This paper introduces a new model to simulate the progression of senile plaques, focusing on scenarios where concentrations of amyloid beta (Aβ) monomers and aggregates vary between neurons. Extracellular variations in these concentrations may arise due to limited diffusivity of Aβ monomers and a high rate of Aβ monomer production at lipid membranes, requiring a substantial concentration gradient for diffusion-driven transport of Aβ monomers. The dimensionless formulation of the model is presented, which identifies four key dimensionless parameters governing the solutions for Aβ monomer and aggregate concentrations, as well as the radius of a growing Aβ plaque within the control volume. These parameters include the dimensionless diffusivity of Aβ monomers, the dimensionless rate of Aβ monomer production, and the dimensionless half-lives of Aβ monomers and aggregates. A dimensionless parameter is then introduced to evaluate the validity of the lumped capacitance approximation. An approximate solution is derived for the scenario involving large diffusivity of Aβ monomers and dysfunctional protein degradation machinery, resulting in infinitely long half-lives for Aβ monomers and aggregates. In this scenario, the concentrations of Aβ aggregates and the radius of the Aβ plaque depend solely on a single dimensionless parameter that characterizes the rate of Aβ monomer production. According to the approximate solution, the concentration of Aβ aggregates is linearly dependent on the rate of monomer production, and the radius of an Aβ plaque is directly proportional to the cube root of the rate of monomer production. However, when departing from the conditions of the approximate solution (e.g., finite half-lives), the concentrations of Aβ monomers and aggregates, along with the plaque radius, exhibit complex dependencies on all four dimensionless parameters. For instance, under physiological half-life conditions, the plaque radius reaches a maximum value and stabilizes thereafter.

Fyn Kinase in Alzheimer's Disease: Unraveling Molecular Mechanisms and Therapeutic Implications

Alzheimer's disease, characterized by the accumulation of abnormal protein aggregates and neuronal damage in the brain, leads to a gradual decline in cognitive function and memory. As a complex neurodegenerative disorder, it involves disruptions in various biochemical pathways and neurotransmitter systems, contributing to the progressive loss of neurons and synaptic connections. The complexity of Alzheimer's signaling pathways complicates treatment, presenting a formidable challenge in the quest for effective therapeutic interventions. A member of the Src family of kinases (SFKs), Fyn, is a type of non-receptor tyrosine kinase that has been linked to multiple essential CNS processes, such as myelination and synaptic transmission. Fyn is an appealing target for AD treatments because it is uniquely linked to the two major pathologies in AD by its interaction with tau, in addition to being activated by amyloid-beta (Aβ) through PrPC. Fyn mediates neurotoxicity and synaptic impairments caused by Aβ and is involved in regulating the process of Aβ synthesis.Additionally, the tau protein's tyrosine phosphorylation is induced by Fyn. Fyn is also a challenging target because of its widespread body expression and strong homology with other kinases of the Src family, which could cause unintentional off-target effects. This review emphasizes signaling pathways mediated by Fyn that govern neuronal development and plasticity while also summarizing the most noteworthy recent research relevant to Fyn kinase's function in the brain. Additionally, the therapeutic inhibition of Fyn kinase has been discussed, with a focus on the Fyn kinase inhibitors that are in clinical trials, which presents a fascinating opportunity for targeting Fyn kinase in the creation of possible therapeutic approaches for the management of Alzheimer's disease.

Exploring the Aβ1-42 fibrillogenesis timeline by atomic force microscopy and surface enhanced Raman spectroscopy

Introduction: Alzheimer's disease (AD) is a progressive debilitating neurological disorder representing the most common neurodegenerative disease worldwide. Although the exact pathogenic mechanisms of AD remain unresolved, the presence of extracellular amyloid-β peptide 1-42 (Aβ1-42) plaques in the parenchymal and cortical brain is considered one of the hallmarks of the disease. Methods: In this work, we investigated the Aβ1-42 fibrillogenesis timeline up to 48 h of incubation, providing morphological and chemo-structural characterization of the main assemblies formed during the aggregation process of Aβ1-42, by atomic force microscopy (AFM) and surface enhanced Raman spectroscopy (SERS), respectively. Results: AFM topography evidenced the presence of characteristic protofibrils at early-stages of aggregation, which form peculiar macromolecular networks over time. SERS allowed to track the progressive variation in the secondary structure of the aggregation species involved in the fibrillogenesis and to determine when the β-sheet starts to prevail over the random coil conformation in the aggregation process. Discussion: Our research highlights the significance of investigating the early phases of fibrillogenesis to better understand the molecular pathophysiology of AD and identify potential therapeutic targets that may prevent or slow down the aggregation process.