Clinical Pharmacokinetics and Safety of ALZ-801, a Novel Prodrug of Tramiprosate in Development for the Treatment of Alzheimer's Disease

Harnessing marine resources for Alzheimer's therapy: A review integrating bioactivity and molecular docking

Alzheimer's disease (AD) is a neurodegenerative condition resulting in cognitive impairment and the formation of neurofibrillary tangles and plaques in the brain. The drivers of AD's molecular progression and pathology include the accumulation of amyloid β protein (Aβ); thus, Aβ is an intervention target. However, the limitations in clinical trials of Aβ-targeted medicine and the failure to intervene in disease progression have raised concerns about the use of this drug and its veracious route. In particular, we comprehensively reviewed the potential effect of marine compounds and the mechanism of isolation and extraction from marine organisms resulting in the optimization of AD treatment. Furthermore, the hub compounds were docked with Beta-secretase receptors to strengthen the extrapolation of mechanistic interactions thus inhibiting the activity of an enzyme. An extensive review revealed that marine aquaculture and its byproducts are a promising source and isolated with green methods or less investment, ensuring their sustainability. MNPs harbor specific pharmacological features that enable them to exert neuroprotective effects by minimizing events such as Aβ peptide formation and reactive oxygen species (ROS) generation.

Targeting protein disorder: the next hurdle in drug discovery

Intrinsically disordered proteins have key signalling and regulatory roles in cells and are frequently dysregulated in diseases such as cancer, neurodegeneration, inflammation and autoimmune disorders. Preventing the pathological functions mediated by structural disorder is crucial to successfully target proteins that drive transcription, biomolecular condensation and protein aggregation. However, owing to their heterogeneous, highly dynamic structural states, with ensembles of rapidly interconverting conformations, disordered proteins have been considered largely 'undruggable' by traditional approaches. Here, we review key developments of the field and suggest that the synergy of advanced experimental and computational approaches needs to be pursued to conquer this barrier in drug discovery.

Alzheimer's Disease and Frontotemporal Dementia: A Review of Pathophysiology and Therapeutic Approaches

Alzheimer's disease (AD) is a devastating form of dementia, with the number of affected individuals rising sharply. The main hallmarks of the disease include amyloid-beta plaque deposits and neurofibrillary tangles consisting of hyperphosphorylated tau protein, besides other pathological features that contribute to the disease's complexity. The causes of sporadic AD are multifactorial and mostly age-related and involve risk factors such as diabetes and cardiovascular or cerebrovascular disorders. Frontotemporal dementia (FTD) is another type of dementia characterized by a spectrum of behaviors, memory, and motor abnormalities and associated with abnormal depositions of protein aggregation, including tau protein. Currently approved medications are symptomatic, and no disease-modifying therapy is available to halt the disease progression. Therefore, the development of multi-targeted therapeutic approaches could hold promise for the treatment of AD and other neurodegenerative disorders, including tauopathies. In this article, we will discuss the pathophysiology of AD and FTD, the proposed hypotheses, and current therapeutic approaches, highlighting the development of novel drug candidates and the progress of clinical trials in this field of research.

Combination of Epigallocatechin-3-Gallate and Tramiprosate Prevent Accumulation of Intracellular Aβ and Dysfunctional Autophagy-Lysosomal Pathway at Earliest Stage of Transdifferentiation of Mesenchymal Stromal Cells into PSEN1 E280A Cholinergic-like Neurons

Familial Alzheimer's disease (FAD) caused by presenilin 1 (PSEN1) E280A induces the aberrant accumulation of intracellular Aβ (iAβ) in cholinergic-like neurons (ChLNs). How early iAβ accumulates in the development of ChLNs is still unknown. Consequently, the timing of appropriate therapeutic approaches against FAD is unclear. To determine the earliest iAβ in PSEN1 E280A ChLNs, flow cytometry and immunofluorescence microscopy were used to follow the development of menstrual mesenchymal stromal cells (MenSCs) into ChLNs (proliferation marker Ki67, cluster of differentiation 73 (CD73), neuronal nuclei (NeuN) marker, choline acetyl transferase (ChAT)), the kinetics of iAβ accumulation, and the simultaneous evaluation of other associated markers (e.g., DJ-1C106-SO3; lysosomes; phosphatidylethanolamine-conjugated microtubule-associated protein 1A/1B light chain 3, LC3-II; cleaved caspase 3 (CC3)) at 0, 1, 3, 5, and 7 days. To reverse the PSEN1 E280A phenotype, we used rapamycin (RAP), verubecestat (VER), compound E (CE), epigallocatechin-3-gallate (EGCG), and tramiprosate (TM) in WT and mutant ChLNs. We found that PSEN1 E280A did not induce significant differences in the NeuN marker and ChAT in MenSCs transitioning to ChLNs. The iAβ accumulates at the earliest cholinergic developmental stage from day 0 (18%, at MenSCs stage) to day 7 (46%, at ChLNs stage), i.e., iAβ increased +156% in mutant compared to WT cells (1-6%). A significant increase in DJ-1C106-SO3 occurs only at day 7 (+250%). While neither CC3 (0-1%) nor lysosomes were different between WT and mutant cells at any time point, a stepwise increase in autophagosome accumulation was observed from day 3 (15%) to day 7 (79%), i.e., +427%, in mutant cells. While neither RAP, VER, nor CE was able to completely reduce all PSEN1 E280A-induced markers in ChLNs, the combination of EGCG and TM was more effective in removing these markers than EGCG and TM alone in PSEN1 E280A ChLNs. Given that this investigation is based on a single menstrual blood sample from WT and PSEN1 E280A, our results should be considered exploratory. Larger sample sizes are needed.

Exploring neuropharmacokinetics: mechanisms, models, and clinical implications

Neuropharmacokinetics is an emerging field dedicated to understanding the pharmacokinetics of drugs within the central nervous system (CNS), with a particular emphasis on overcoming the challenges posed by the blood-brain barrier. This paper reviews the latest advancements in drug delivery strategies, including nanoparticle-based systems, receptor-mediated transcytosis, and efflux transporter inhibition, which have been designed to enhance drug penetration into the brain. Additionally, the use of advanced imaging techniques such as positron emission tomography, functional magnetic resonance imaging, and magnetic resonance imaging with contrast agents has provided critical insights into drug distribution, receptor occupancy, and the functional impact of therapeutic agents within the CNS. These innovations not only enhance our understanding of CNS drug action but also pave the way for more effective treatments for neurological and psychiatric disorders.

Human serum albumin-3-amino-1-propanesulfonic acid conjugate inhibits amyloid-β aggregation and mitigates cognitive decline in Alzheimer's disease

Alzheimer's disease (AD) is the most commonly occurring brain disorder, characterized by the accumulation of amyloid-β (Aβ) and tau, subsequently leading to neurocognitive decline. 3-Amino-1-propanesulfonic acid (TPS) and its prodrug, currently under clinical trial III, serve as promising therapeutic agents targeting Aβ pathology by specifically preventing monomer-to-oligomer formation. Inspired by the potency of TPS prodrug, we hypothesized that conjugating TPS with human serum albumin (HSA) could enhance brain delivery and synergistically inhibit Aβ aggregation in mild to moderate AD. Thus, we prepared and extensively characterized HSA-TPS (h-TPS) conjugate using an eco-friendly coupling method. In vitro studies on Aβ aggregation kinetics and AFM imaging revealed significant prevention of Aβ aggregation. Additionally, h-TPS significantly reduced Aβ-induced neurotoxicity and H2O2-mediated reactive oxygen species (ROS) stress in SH-SY5Y cells. Moreover, h-TPS administration improved blood-brain barrier permeability and cellular uptake into neuronal cells as well as showed in vivo uptake inside the brain within 1 h. In vivo studies using an Aβ1-42-induced acute AD rat model exhibited a dose-dependent significant reduction in hippocampal Aβ levels and restoration of declined spatial learning and memory with h-TPS treatment. Overall, findings suggest that h-TPS conjugate might be a promising neuroprotective agent for preventing Aβ aggregation in mild to moderate AD.

Clinical Pharmacokinetics of Oral ALZ-801/Valiltramiprosate in a 2-Year Phase 2 Trial of APOE4 Carriers with Early Alzheimer's Disease

INTRODUCTION

ALZ-801/valiltramiprosate is an oral, small-molecule inhibitor of β-amyloid (Aβ) oligomer formation in late-stage development as a potential disease-modifying therapy for Alzheimer's disease (AD). ALZ-801, a valine-conjugated prodrug, is rapidly converted to tramiprosate after oral dosing. Upon conversion to tramiprosate, it generates a single metabolite, 3-sulfopropanoic acid (3-SPA). Both tramiprosate and 3-SPA are active anti-Aβ oligomer agents that mediate ALZ-801's central mechanism of action (MOA). We summarize herein the pharmacokinetics (PK) of ALZ-801 in apolipoprotein ε4 (APOE4) carrier subjects with early AD from a phase 2 trial.

METHODS

The ALZ-801 phase 2 study was designed to evaluate longitudinal effects of ALZ-801 (265 mg BID) on plasma, cerebrospinal fluid (CSF) and volumetric magnetic resonance imaging (MRI) AD biomarkers, and clinical outcomes over 104 weeks in APOE4 carriers with early AD. Eighty-four subjects (31 APOE4/4 homozygotes and 53 APOE3/4 heterozygotes) with positive CSF biomarkers of amyloid and tau pathology were enrolled. The phase 2 study included a substudy of 24 subjects to provide 8-h steady-state PK at 65 weeks. Sparse PK samples were also analyzed. The relationships between plasma PK exposure and clinical characteristics [i.e., sex, APOE genotype, age, body mass index (BMI), estimated glomerular filtration rate (eGFR), concomitant acetylcholinesterase inhibitor (AChEI) use, and tablet lot] were evaluated.

RESULTS

The steady-state plasma PK results were closely aligned with the previous 2-week PK in the ALZ-801 phase 1b study in APOE4 carrier subjects with AD, as well as a phase 1 7-day PK study in heathy elderly volunteers. Following oral dosing, ALZ-801 was rapidly converted to the active moieties, tramiprosate and 3-SPA. The intersubject variability in plasma drug levels was low, confirming the superior performance of ALZ-801 versus oral tramiprosate tablet (150 mg BID) from the earlier tramiprosate phase 3 trials. Correlation analysis versus clinical characteristics showed that plasma exposures (Cmax and AUC8h) for ALZ-801, tramiprosate, and 3-SPA were not affected by sex, APOE genotype, age, BMI, concomitant AChEI use, or tablet lot. Plasma exposures of both tramiprosate and 3-SPA, but not ALZ-801, were inversely correlated with eGFR, in line with renal excretion as the primary route of elimination. ALZ-801 was well tolerated without new safety signals or events of amyloid-related imaging abnormalities (ARIA).

CONCLUSIONS

The steady-state PK profile of oral ALZ-801 in subjects with early AD was not affected by sex, APOE genotype, age, BMI, concomitant use of AChEI, or tablet lot. The inverse relationship of plasma exposures of tramiprosate and 3-SPA, but not ALZ-801, versus eGFR is consistent with renal clearance as the primary route of elimination for tramiprosate and 3-SPA (active moieties), and with the efficient conversion of ALZ-801 prodrug to the active moieties after dosing. These results demonstrate that ALZ-801 displays favorable PK properties without evidence of interactions with demographic characteristics and support its development as an oral disease-modifying treatment for AD.

TRIAL REGISTRATION

https://clinicaltrials.gov/study/NCT04693520 .

Comprehensive investigation of multiple targets in the development of newer drugs for the Alzheimer's disease

Alzheimer's disease, a significant contributor to dementia, is rapidly becoming a serious healthcare concern in the 21st century. The alarming number of patients with Alzheimer's disease is steadily increasing, which is contributed by the dearth of treatment options. The current treatment for Alzheimer's disease is heavily dependent on symptomatic treatment that has failed to cure the disease despite huge investments in the development of drugs. The clinical treatment of Alzheimer's disease with limited drugs is generally targeted towards the inhibition of N-methyl-d-aspartate receptor and acetylcholine esterase, which only elevate cognition levels for a limited period. Beyond the aforementioned molecular targets, β-amyloid was much explored with little success and thus created a feel and palpable growing emphasis on discovering new putative and novel targets for AD. This has inspired medicinal chemists to explore new targets, including microglia, triggering receptors expressed on myeloid cells 2 (Trem-2), and notum carboxylesterase, to discover new lead compounds. This review explores the functions, pathophysiological roles, and importance of all AD-related targets that address therapeutic and preventive approaches for the treatment and protection of Alzheimer's disease.

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.

ALZ-801 prevents amyloid β-protein assembly and reduces cytotoxicity: A preclinical experimental study

Alzheimer's disease (AD) is the most prevalent age-related neurodegenerative disorder, mainly characterized by amyloid β (Aβ) accumulation in the brain. Numerous new agents are currently undergoing clinical trials as disease-modifying therapies (DMTs) targeting Aβ. ALZ-801 is a promising candidate DMT for AD, with a phase 3 trial of ALZ-801 ongoing specifically for apolipoprotein E (APOE) ε4 homozygous patients with early-stage AD. This study aimed to examine the effects of ALZ-801 on Aβ assembly and explore its toxicological profile. Thioflavin T (ThT) assays and two imaging modalities-transmission electron microscopy (TEM) and high-speed atomic force microscopy (HS-AFM)-were used to evaluate ALZ-801's effects on Aβ assembly. To assess the effect of ALZ-801 on Aβ42-induced cytotoxicity, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays and lactate dehydrogenase (LDH) assays were performed. ThT assays revealed increased lag time and decreased fluorescence in the presence of ALZ-801, confirming inhibition of Aβ42 fibril formation, as confirmed by TEM. Real-time observation using HS-AFM revealed that ALZ-801 inhibited the formation of Aβ42 fibril from low-molecular-weight (LMW)-Aβ42 in the presence of Aβ42 seeds. HS-AFM also revealed that globular aggregates from LMW-Aβ42 were significantly larger with ALZ-801, with few fibrils noted. MTT and LDH assays indicated that ALZ-801 prevented LMW-Aβ42-induced cytotoxicity but did not reduce cytotoxicity induced by high-molecular-weight-Aβ42. ALZ-801 can inhibit Aβ42 aggregation by preventing both nucleus formation and fibril elongation, while promoting large globular oligomer formation, and can significantly reduce LMW-Aβ42-induced cytotoxicity. These findings underscore the potential of ALZ-801 as an effective DMT for APOE ε4 homozygous patients with AD.

Drug delivery strategies with lipid-based nanoparticles for Alzheimer's disease treatment

Alzheimer's disease (AD) is a distinctive form of dementia characterized by age-related cognitive decline and memory impairment. A key hallmark of AD is the irreversible overaccumulation of beta-amyloid (Aβ) in the brain, associated with neuroinflammation and neuronal death. Although Aβ clearance and immunoregulation have been the major therapeutic strategies for AD, highly selective transport across the blood-brain barrier (BBB) negatively affects the delivery efficacy of the drugs without the ability to cross the BBB. In this review, we discuss the potential of lipid-based nanoparticles (LBNs) as promising vehicles for drug delivery in AD treatment. LBNs, composed of phospholipid mono- or bilayer, have attracted attention due to their exceptional cellular penetration capabilities and drug loading capabilities, which also facilitate cargo transcytosis across the BBB. Recent advances in the development and engineering of LBNs overcome the existing limitations of the current clinical approaches for AD treatment by addressing off-target effects and low therapeutic efficacy. Here, we review the transport pathways across the BBB, as well as various types of LBNs for AD therapy, including exosomes, liposomes, solid lipid nanoparticles (SLNs), and nanostructured lipid carriers (NLCs), to elucidate their distinctive properties, preparation methodologies, and therapeutic efficacy, thereby offering innovative avenues for novel drug development for clinical translation in AD therapy.

P2Y1 receptor in Alzheimer's disease

Alzheimer's disease is the most frequent form of dementia characterized by the deposition of amyloid-beta plaques and neurofibrillary tangles consisting of hyperphosphorylated tau. Targeting amyloid-beta plaques has been a primary direction for developing Alzheimer's disease treatments in the last decades. However, existing drugs targeting amyloid-beta plaques have not fully yielded the expected results in the clinic, necessitating the exploration of alternative therapeutic strategies. Increasing evidence unravels that astrocyte morphology and function alter in the brain of Alzheimer's disease patients, with dysregulated astrocytic purinergic receptors, particularly the P2Y1 receptor, all of which constitute the pathophysiology of Alzheimer's disease. These receptors are not only crucial for maintaining normal astrocyte function but are also highly implicated in neuroinflammation in Alzheimer's disease. This review delves into recent insights into the association between P2Y1 receptor and Alzheimer's disease to underscore the potential neuroprotective role of P2Y1 receptor in Alzheimer's disease by mitigating neuroinflammation, thus offering promising avenues for developing drugs for Alzheimer's disease and potentially contributing to the development of more effective treatments.

"Current and emerging drug therapies in Alzheimer's disease: A pathophysiological Perspective"

The analytical and experimental investigation of several targets and biomarkers that help in explaining significant cognitive deficits, covering drug development and precision medicine aimed at different chronic neurodegenerative conditions such as Alzheimer's disease (AD), Parkinson's disease, synaptic dysfunction, brain damage from neuronal apoptosis, and other disease pathologies; this served as the foundation for all phase studies. The focus of current therapeutic approaches is on developing humanized antibodies, agonist and antagonist drugs, receptors, signaling molecules, major targeted drug-metabolizing enzymes, and other metabolites to treat neurodegeneration in the AD brain brought on by tau hyperphosphorylation, amyloid plagues, or other cholinergic effects. The five A's-amnesia, agnosia, aphasia, apraxia, and anomia-are the typical symptoms associated with AD. While the main goal of drug therapeutics studies is modified amino acids acting as pro-drugs, pharmacokinetics studies and trends in evaluating drug-drug interactions focus on interactions between drugs and antibodies, drugs and therapeutic biologics like metabolites, herbs, interleukin-based, and gene silencing mechanism-based. Studies on the biotransformation of xenobiotic compounds and the metabolism of exogenous and endogenous substances are conducted under Phase I, Phase II, and Phase III trials because the pivotal pharmacokinetic properties of drugs, such as absorption, distribution, metabolism, and excretion (ADME), aid in understanding variations in the crucial improvement of various target drugs. This review also highlights the developments in soon-to-be genetically created targeted medications that may serve as ground-breaking treatments for cholinergic illnesses in the brains of AD patients and other neurodegenerative conditions.

Disease-modifying therapies for Alzheimer's disease: Clinical trial progress and opportunity

The U.S. Food and Drug Administration (FDA) recently approved lecanemab and donanemab for the treatment of early symptomatic Alzheimer's disease (AD) after their phase III trials reached endpoints. These two anti-amyloid β monoclonal antibodies represent the latest promise of disease-modifying therapy (DMT) for AD, which undoubtedly reignites new hope for DMTs to combat the staggering financial and human costs of AD. However, in addition to these two successful antibodies, there have been enormous efforts to develop DMTs in various aspects to meet the therapeutic requirement of AD. In this review, we delineate the core principles and methodologies of diverse DMTs, covering the advances in clinical trials of drug candidates that either have been discontinued, completed, or are ongoing, as well as brain stimulation and lifestyle interventions. In addition, by overseeing the fate of various candidate molecules, we hope to provide references and ideas for prospective approaches and promising applications of DTMs for AD, particularly in terms of universality and clinical application economics, to optimize efficacy and maximize AD patient benefits in the future.

Pathogenesis, diagnostics, and therapeutics for Alzheimer's disease: Breaking the memory barrier

Alzheimer's disease (AD) is the most common cause of dementia and accounts for 60-70 % of all cases. It affects millions of people worldwide. AD poses a substantial economic burden on societies and healthcare systems. AD is a progressive neurodegenerative disorder characterized by cognitive decline, memory loss, and impaired daily functioning. As the prevalence of AD continues to increase, understanding its pathogenesis, improving diagnostic methods, and developing effective therapeutics have become paramount. This comprehensive review delves into the intricate mechanisms underlying AD, explores the current state of diagnostic techniques, and examines emerging therapeutic strategies. By revealing the complexities of AD, this review aims to contribute to the growing body of knowledge surrounding this devastating disease.

Structure-Activity Relationship of Fluorinated Benzenesulfonamides as Inhibitors of Amyloid-β Aggregation

Amyloid-beta aggregation is considered one of the factors influencing the onset of the Alzheimer's disease. Early prevention of such aggregation should alleviate disease condition by applying small molecule compounds that shift the aggregation equilibrium toward the soluble form of the peptide or slow down the process. We have discovered that fluorinated benzenesulfonamides of particular structure slowed the amyloid-beta peptide aggregation process by more than three-fold. We synthesized a series of ortho-para and meta-para double-substituted fluorinated benzenesulfonamides that inhibited the aggregation process to a variable extent yielding a detailed picture of the structure-activity relationship. Analysis of compound chemical structure effect on aggregation in artificial cerebrospinal fluid showed the necessity to arrange the benzenesulfonamide, hydrophobic substituent, and benzoic acid in a particular way. The amyloid beta peptide aggregate fibril structures varied in cross-sectional height depending on the applied inhibitor indicating the formation of a complex with the compound. Application of selected inhibitors increased the survivability of cells affected by the amyloid beta peptide. Such compounds may be developed as drugs against Alzheimer's disease.

Misfolding and aggregation in neurodegenerative diseases: protein quality control machinery as potential therapeutic clearance pathways

The primary challenge in today's world of neuroscience is the search for new therapeutic possibilities for neurodegenerative disease. Central to these disorders lies among other factors, the aberrant folding, aggregation, and accumulation of proteins, resulting in the formation of toxic entities that contribute to neuronal degeneration. This review concentrates on the key proteins such as β-amyloid (Aβ), tau, and α-synuclein, elucidating the intricate molecular events underlying their misfolding and aggregation. We critically evaluate the molecular mechanisms governing the elimination of misfolded proteins, shedding light on potential therapeutic strategies. We specifically examine pathways such as the endoplasmic reticulum (ER) and unfolded protein response (UPR), chaperones, chaperone-mediated autophagy (CMA), and the intersecting signaling of Keap1-Nrf2-ARE, along with autophagy connected through p62. Above all, we emphasize the significance of these pathways as protein quality control mechanisms, encompassing interventions targeting protein aggregation, regulation of post-translational modifications, and enhancement of molecular chaperones and clearance. Additionally, we focus on current therapeutic possibilities and new, multi-target approaches. In conclusion, this review systematically consolidates insights into emerging therapeutic strategies predicated on protein aggregates clearance.

Alzheimer's disease: a review on the current trends of the effective diagnosis and therapeutics

The most prevalent cause of dementia is Alzheimer's disease. Cognitive decline and accelerating memory loss characterize it. Alzheimer's disease advances sequentially, starting with preclinical stages, followed by mild cognitive and/or behavioral impairment, and ultimately leading to Alzheimer's disease dementia. In recent years, healthcare providers have been advised to make an earlier diagnosis of Alzheimer's, prior to individuals developing Alzheimer's disease dementia. Regrettably, the identification of early-stage Alzheimer's disease in clinical settings can be arduous due to the tendency of patients and healthcare providers to disregard symptoms as typical signs of aging. Therefore, accurate and prompt diagnosis of Alzheimer's disease is essential in order to facilitate the development of disease-modifying and secondary preventive therapies prior to the onset of symptoms. There has been a notable shift in the goal of the diagnosis process, transitioning from merely confirming the presence of symptomatic AD to recognizing the illness in its early, asymptomatic phases. Understanding the evolution of disease-modifying therapies and putting effective diagnostic and therapeutic management into practice requires an understanding of this concept. The outcomes of this study will enhance in-depth knowledge of the current status of Alzheimer's disease's diagnosis and treatment, justifying the necessity for the quest for potential novel biomarkers that can contribute to determining the stage of the disease, particularly in its earliest stages. Interestingly, latest clinical trial status on pharmacological agents, the nonpharmacological treatments such as behavior modification, exercise, and cognitive training as well as alternative approach on phytochemicals as neuroprotective agents have been covered in detailed.

Approved drugs and natural products at clinical stages for treating Alzheimer's disease

Alzheimer's disease (AD) remains the foremost cause of dementia and represents a significant unmet healthcare need globally. The complex pathogenesis of AD, characterized by various pathological and physiological events, has historically challenged the development of anti-AD drugs. However, recent breakthroughs in AD drug development, including the approvals of aducanumab, lecanemab, and sodium oligomannate (GV-971), have ended a nearly two-decade hiatus in the introduction of new AD drugs. These developments have addressed long-standing challenges in AD drug development, marking a substantial shift in the therapeutic landscape of AD. Moreover, natural products (NPs) have shown promise in AD drug research, with several currently under clinical investigation. Their distinct properties and mechanisms of action offer new avenues to complement and enhance existing AD treatment approaches. This review article aims to provide an overview of the recent advancements and prospects in AD therapeutics, focusing on both NPs and approved drugs.

Revolutionizing Alzheimer's treatment: Harnessing human serum albumin for targeted drug delivery and therapy advancements

Alzheimer's disease (AD) is a neurodegenerative disorder initiated by amyloid-beta (Aβ) accumulation, leading to impaired cognitive function. Several delivery approaches have been improved for AD management. Among them, human serum albumin (HSA) is broadly employed for drug delivery and targeting the Aβ in AD owing to its biocompatibility, Aβ inhibitory effect, and nanoform, which showed blood-brain barrier (BBB) crossing ability via glycoprotein 60 (gp60) receptor and secreted protein acidic and rich in cysteine (SPARC) protein to transfer the drug molecules in the brain. Thus far, there is no previous review focusing on HSA and its drug delivery system in AD. Hence, the reviewed article aimed to critically compile the HSA therapeutic as well as drug delivery role in AD management. It also delivers information on how HSA-incorporated nanoparticles with surfaced embedded ligands such as TAT, GM1, and so on, not only improve BBB permeability but also increase neuron cell targetability in AD brain. Additionally, Aβ and tau pathology, including various metabolic markers likely BACE1 and BACE2, etc., are discussed. Besides, the molecular interaction of HSA with Aβ and its distinctive forms are critically reviewed that HSA can segregate Zn(II) and Cu(II) metal ions from Aβ owing to high affinity. Furthermore, the BBB drug delivery challenges in AD are addressed. Finally, the clinical formulation of HSA for the management of AD is critically discussed on how the HSA inhibits Aβ oligomer and fibril, while glycated HSA participates in amyloid plaque formation, i.e., β-structure sheet formation. This review report provides theoretical background on HSA-based AD drug delivery and makes suggestions for future prospect-related work.

The Interplay of Protein Aggregation, Genetics, and Oxidative Stress in Alzheimer's Disease: Role for Natural Antioxidants and Immunotherapeutics

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that comprises amyloid-beta protein (Aβ) as a main component of neuritic plaques. Its deposition is considered a trigger for AD pathogenesis, progression, and the clinical symptoms of cognitive impairment. Some distinct pathological features of AD include phosphorylation of tau protein, oxidative stress, and mitochondrial dysfunction. These pathological consequences tend to produce reactive oxygen species (ROS), resulting in the dysregulation of various signaling pathways of neuroinflammation and neurodegeneration. The relationship between the Aβ cascade and oxidative stress in AD pathogenesis is like a "chicken and egg" story, with the etiology of the disease regarding these two factors remaining a question of "which comes first." However, in this review, we have tried our best to clarify the interconnection between these two mechanisms and to show the precise cause-and-effect relationship. Based on the above hallmarks of AD, several therapeutic strategies using natural antioxidants, monoclonal antibodies, and vaccines are employed as anti-Aβ therapy to decrease ROS, Aβ burden, chronic neuroinflammation, and synaptic failure. These natural antioxidants and immunotherapeutics have demonstrated significant neuroprotective effects and symptomatic relief in various in vitro and in vivo models, as well as in clinical trials for AD. However, none of them have received final approval to enter the drug market for mitigating AD. In this review, we extensively elaborate on the pitfalls, assurances, and important crosstalk between oxidative stress and Aβ concerning current anti-Aβ therapy. Additionally, we discuss future strategies for the development of more Aβ-targeted approaches and the optimization of AD treatment and mitigation.

Analysis of Cerebrospinal Fluid, Plasma β-Amyloid Biomarkers, and Cognition from a 2-Year Phase 2 Trial Evaluating Oral ALZ-801/Valiltramiprosate in APOE4 Carriers with Early Alzheimer's Disease Using Quantitative Systems Pharmacology Model

INTRODUCTION

ALZ-801/valiltramiprosate is an oral, small-molecule inhibitor of beta-amyloid (Aβ) aggregation and oligomer formation in late-stage development as a disease-modifying therapy for early Alzheimer's disease (AD). The present investigation provides a quantitative systems pharmacology (QSP) analysis of amyloid fluid biomarkers and cognitive results from a 2-year ALZ-801 Phase 2 trial in APOE4 carriers with early AD.

METHODS

The single-arm, open-label phase 2 study evaluated effects of ALZ-801 265 mg two times daily (BID) on cerebrospinal fluid (CSF) and plasma amyloid fluid biomarkers over 104 weeks in APOE4 carriers with early AD [Mini-Mental State Examination (MMSE) ≥ 22]. Subjects with positive CSF biomarkers for amyloid (Aβ42/Aβ40) and tau pathology (p-tau181) were enrolled, with serial CSF and plasma levels of Aβ42 and Aβ40 measured over 104 weeks. Longitudinal changes of CSF Aβ42, plasma Aβ42/Aβ40 ratio, and cognitive Rey Auditory Verbal Learning Test (RAVLT) were compared with the established natural disease trajectories in AD using a QSP approach. The natural disease trajectory data for amyloid biomarkers and RAVLT were extracted from a QSP model and an Alzheimer's disease neuroimaging initiative population model, respectively. Analyses were stratified by disease severity and sex.

RESULTS

A total of 84 subjects were enrolled. Excluding one subject who withdrew at the early stage of the trial, data from 83 subjects were used for this analysis. The ALZ-801 treatment arrested the progressive decline in CSF Aβ42 level and plasma Aβ42/Aβ40 ratio, and stabilized RAVLT over 104 weeks. Both sexes showed comparable responses to ALZ-801, whereas mild cognitive impairment (MCI) subjects (MMSE ≥ 27) exhibited a larger biomarker response compared with more advanced mild AD subjects (MMSE 22-26).

CONCLUSIONS

In this genetically defined and biomarker-enriched early AD population, the QSP analysis demonstrated a positive therapeutic effect of oral ALZ-801 265 mg BID by arresting the natural decline of monomeric CSF and plasma amyloid biomarkers, consistent with the target engagement to prevent their aggregation into soluble neurotoxic oligomers and subsequently into insoluble fibrils and plaques over 104 weeks. Accompanying the amyloid biomarker changes, ALZ-801 also stabilized the natural trajectory decline of the RAVLT memory test, suggesting that the clinical benefits are consistent with its mechanism of action. This sequential effect arresting the disease progression on biomarkers and cognitive decline was more pronounced in the earlier symptomatic stages of AD. The QSP analysis provides fluid biomarker and clinical evidence for ALZ-801 as a first-in-class, oral small-molecule anti-Aβ oligomer agent with disease modification potential in AD.

TRIAL REGISTRY

https://clinicaltrials.gov/study/NCT04693520.

Effects of Oral ALZ-801/Valiltramiprosate on Plasma Biomarkers, Brain Hippocampal Volume, and Cognition: Results of 2-Year Single-Arm, Open-Label, Phase 2 Trial in APOE4 Carriers with Early Alzheimer's Disease

INTRODUCTION

ALZ-801/valiltramiprosate is a small-molecule oral inhibitor of beta amyloid (Aβ) aggregation and oligomer formation being studied in a phase 2 trial in APOE4 carriers with early Alzheimer's disease (AD) to evaluate treatment effects on fluid and imaging biomarkers and cognitive assessments.

METHODS

The single-arm, open-label phase 2 trial was designed to evaluate the effects of the ALZ-801 265 mg tablet taken twice daily (after 2 weeks once daily) on plasma fluid AD biomarkers, hippocampal volume (HV), and cognition over 104 weeks in APOE4 carriers. The study enrolled subjects aged 50-80 years, with early AD [Mini-Mental State Examination (MMSE) ≥ 22, Clinical Dementia Rating-Global (CDR-G) 0.5 or 1], apolipoprotein E4 (APOE4) genotypes including APOE4/4 and APOE3/4 genotypes, and positive cerebrospinal fluid (CSF) AD biomarkers or prior amyloid scans. The primary outcome was plasma p-tau181, HV evaluated by magnetic resonance imaging (MRI) was the key secondary outcome, and plasma Aβ42 and Aβ40 were the secondary biomarker outcomes. The cognitive outcomes were the Rey Auditory Verbal Learning Test and the Digit Symbol Substitution Test. Safety and tolerability evaluations included treatment-emergent adverse events and amyloid-related imaging abnormalities (ARIA). The study was designed and powered to detect 15% reduction from baseline in plasma p-tau181 at the 104-week endpoint. A sample size of 80 subjects provided adequate power to detect this difference at a significance level of 0.05 using a two-sided paired t-test.

RESULTS

The enrolled population of 84 subjects (31 homozygotes and 53 heterozygotes) was 52% females, mean age 69 years, MMSE 25.7 [70% mild cognitive impairment (MCI), 30% mild AD] with 55% on cholinesterase inhibitors. Plasma p-tau181 reduction from baseline was significant (31%, p = 0.045) at 104 weeks and all prior visits; HV atrophy was significantly reduced (p = 0.0014) compared with matched external controls from an observational Early AD study. Memory scores showed minimal decline from baseline over 104 weeks and correlated significantly with decreased HV atrophy (Spearman's 0.44, p = 0.002). Common adverse events were COVID infection and mild nausea, and no drug-related serious adverse events were reported. Of 14 early terminations, 6 were due to nonserious treatment-emergent adverse events and 1 death due to COVID. There was no vasogenic brain edema observed on MRI over 104 weeks.

CONCLUSIONS

The effect of ALZ-801 on reducing plasma p-tau181 over 2 years demonstrates target engagement and supports its anti-Aβ oligomer action that leads to a robust decrease in amyloid-induced brain neurodegeneration. The significant correlation between reduced HV atrophy and cognitive stability over 2 years suggests a disease-modifying effect of ALZ-801 treatment in patients with early AD. Together with the favorable safety profile with no events of vasogenic brain edema, these results support further evaluation of ALZ-801 in a broader population of APOE4 carriers, who represent two-thirds of patients with AD.

TRIAL REGISTRATION

https://clinicaltrials.gov/study/NCT04693520 .

CoVAMPnet: Comparative Markov State Analysis for Studying Effects of Drug Candidates on Disordered Biomolecules

Computational study of the effect of drug candidates on intrinsically disordered biomolecules is challenging due to their vast and complex conformational space. Here, we developed a comparative Markov state analysis (CoVAMPnet) framework to quantify changes in the conformational distribution and dynamics of a disordered biomolecule in the presence and absence of small organic drug candidate molecules. First, molecular dynamics trajectories are generated using enhanced sampling, in the presence and absence of small molecule drug candidates, and ensembles of soft Markov state models (MSMs) are learned for each system using unsupervised machine learning. Second, these ensembles of learned MSMs are aligned across different systems based on a solution to an optimal transport problem. Third, the directional importance of inter-residue distances for the assignment to different conformational states is assessed by a discriminative analysis of aggregated neural network gradients. This final step provides interpretability and biophysical context to the learned MSMs. We applied this novel computational framework to assess the effects of ongoing phase 3 therapeutics tramiprosate (TMP) and its metabolite 3-sulfopropanoic acid (SPA) on the disordered Aβ42 peptide involved in Alzheimer's disease. Based on adaptive sampling molecular dynamics and CoVAMPnet analysis, we observed that both TMP and SPA preserved more structured conformations of Aβ42 by interacting nonspecifically with charged residues. SPA impacted Aβ42 more than TMP, protecting α-helices and suppressing the formation of aggregation-prone β-strands. Experimental biophysical analyses showed only mild effects of TMP/SPA on Aβ42 and activity enhancement by the endogenous metabolization of TMP into SPA. Our data suggest that TMP/SPA may also target biomolecules other than Aβ peptides. The CoVAMPnet method is broadly applicable to study the effects of drug candidates on the conformational behavior of intrinsically disordered biomolecules.

Review of valiltramiprosate (ALZ-801) for the treatment of Alzheimer's disease: a novel small molecule with disease modifying potential

INTRODUCTION

Alzheimer's disease (AD) is a neurodegenerative condition characterized by progressive cognitive deterioration, functional impairments, and neuropsychiatric symptoms. Valiltramiprosate is a tramiprosate prodrug being investigated as a novel treatment for AD.

AREAS COVERED

The online databases PubMed, Embase, Web of Science, Cochrane Library, and ClinicalTrials.gov were searched using the terms 'ALZ-801' or 'valiltramiprosate.' Alzheon press releases were reviewed for emerging clinical information. Valiltramiprosate is an oral, well-tolerated synthetic valine-conjugate prodrug of tramiprosate. Valiltramiprosate's active metabolite include tramiprosate and 3-sulfopropanoic acid. Proposed mechanism of action is multiligand binding to Aβ42 which stabilizes amyloid monomers to prevent peptide aggregation and oligomerization. Pharmacokinetic studies show 52% oral bioavailability, rapid absorption, approximately 40% brain-drug exposure, and near complete renal clearance. Compared to tramiprosate, valiltramiprosate extends plasma tramiprosate half-life and improves interindividual pharmacokinetic variability. Interim analyses from valiltramiprosate's phase II biomarker trial show: (1) significant reductions in plasma p-tau181 and related AD fluid biomarkers; (2) brain structure preservation and reduced hippocampal atrophy by MRI; and (3) improvements on cognitive assessments at multiple timepoints. Its phase III clinical trial in ApoE ε4 homozygotes is near completion.

EXPERT OPINION

Valiltramiprosate's clinical trial data show early indications of efficacy with potential disease modifying effect in AD.

Combination of Tramiprosate, Curcumin, and SP600125 Reduces the Neuropathological Phenotype in Familial Alzheimer Disease PSEN1 I416T Cholinergic-like Neurons

Familial Alzheimer's disease (FAD) is a complex and multifactorial neurodegenerative disorder for which no curative therapies are yet available. Indeed, no single medication or intervention has proven fully effective thus far. Therefore, the combination of multitarget agents has been appealing as a potential therapeutic approach against FAD. Here, we investigated the potential of combining tramiprosate (TM), curcumin (CU), and the JNK inhibitor SP600125 (SP) as a treatment for FAD. The study analyzed the individual and combined effects of these two natural agents and this pharmacological inhibitor on the accumulation of intracellular amyloid beta iAβ; hyperphosphorylated protein TAU at Ser202/Thr205; mitochondrial membrane potential (ΔΨm); generation of reactive oxygen species (ROS); oxidized protein DJ-1; proapoptosis proteins p-c-JUN at Ser63/Ser73, TP53, and cleaved caspase 3 (CC3); and deficiency in acetylcholine (ACh)-induced transient Ca2+ influx response in cholinergic-like neurons (ChLNs) bearing the mutation I416T in presenilin 1 (PSEN1 I416T). We found that single doses of TM (50 μM), CU (10 μM), or SP (1 μM) were efficient at reducing some, but not all, pathological markers in PSEN 1 I416T ChLNs, whereas a combination of TM, CU, and SP at a high (50, 10, 1 μM) concentration was efficient in diminishing the iAβ, p-TAU Ser202/Thr205, DJ-1Cys106-SO3, and CC3 markers by -50%, -75%, -86%, and -100%, respectively, in PSEN1 I417T ChLNs. Although combinations at middle (10, 2, 0.2) and low (5, 1, 0.1) concentrations significantly diminished p-TAU Ser202/Thr205, DJ-1Cys106-SO3, and CC3 by -69% and -38%, -100% and -62%, -100% and -62%, respectively, these combinations did not alter the iAβ compared to untreated mutant ChLNs. Moreover, a combination of reagents at H concentration was able to restore the dysfunctional ACh-induced Ca2+ influx response in PSEN 1 I416T. Our data suggest that the use of multitarget agents in combination with anti-amyloid (TM, CU), antioxidant (e.g., CU), and antiapoptotic (TM, CU, SP) actions might be beneficial for reducing iAβ-induced ChLN damage in FAD.

Review on anti-alzheimer drug development: approaches, challenges and perspectives

Alzheimer is an irreversible progressive neurodegenerative disease that causes failure of cerebral neurons and disability of the affected person to practice normal daily life activities. There is no concrete evidence to identify the exact reason behind the disease, so several relevant hypotheses emerged, highlighting many possible therapeutic targets, such as acetylcholinesterase, cholinergic receptors, N-methyl d-aspartate receptors, phosphodiesterase, amyloid β protein, protein phosphatase 2A, glycogen synthase kinase-3 beta, β-secretase, γ-secretase, α-secretase, serotonergic receptors, glutaminyl cyclase, tumor necrosis factor-α, γ-aminobutyric acid receptors, and mitochondria. All of these targets have been involved in the design of new potential drugs. An extensive number of these drugs have been studied in clinical trials. However, only galantamine, donepezil, and rivastigmine (ChEIs), memantine (NMDA antagonist), and aducanumab and lecanemab (selective anti-Aβ monoclonal antibodies) have been approved for AD treatment. Many drugs failed in the clinical trials to such an extent that questions have been posed about the significance of some of the aforementioned targets. On the contrary, the data of other drugs were promising and shed light on the significance of their targets for the development of new potent anti-alzheimer drugs.

Prodrugs as empowering tools in drug discovery and development: recent strategic applications of drug delivery solutions to mitigate challenges associated with lead compounds and drug candidates

The delivery of a drug to a specific organ or tissue at an efficacious concentration is the pharmacokinetic (PK) hallmark of promoting effective pharmacological action at a target site with an acceptable safety profile. Sub-optimal pharmaceutical or ADME profiles of drug candidates, which can often be a function of inherently poor physicochemical properties, pose significant challenges to drug discovery and development teams and may contribute to high compound attrition rates. Medicinal chemists have exploited prodrugs as an informed strategy to productively enhance the profiles of new chemical entities by optimizing the physicochemical, biopharmaceutical, and pharmacokinetic properties as well as selectively delivering a molecule to the site of action as a means of addressing a range of limitations. While discovery scientists have traditionally employed prodrugs to improve solubility and membrane permeability, the growing sophistication of prodrug technologies has enabled a significant expansion of their scope and applications as an empowering tool to mitigate a broad range of drug delivery challenges. Prodrugs have emerged as successful solutions to resolve non-linear exposure, inadequate exposure to support toxicological studies, pH-dependent absorption, high pill burden, formulation challenges, lack of feasibility of developing solid and liquid dosage forms, first-pass metabolism, high dosing frequency translating to reduced patient compliance and poor site-specific drug delivery. During the period 2012-2022, the US Food and Drug Administration (FDA) approved 50 prodrugs, which amounts to 13% of approved small molecule drugs, reflecting both the importance and success of implementing prodrug approaches in the pursuit of developing safe and effective drugs to address unmet medical needs.

Proteomics revealed an association between ribosome-associated proteins and amyloid beta deposition in Alzheimer's disease

Most scholars believe that amyloid-beta (Aβ) has the potential to induce apoptosis, stimulate an inflammatory cascade, promote oxidative stress and exacerbate the pathological progression of Alzheimer's disease (AD). Therefore, it is crucial to investigate the deposition of Aβ in AD. At approximately 6 months of age, APP/PS1 double transgenic mice gradually exhibit the development of plaques, as well as spatial and learning impairment. Notably, the hippocampus is specifically affected in the course of AD. Herein, 6-month-old APP/PS1 double transgenic mice were utilized, and the differentially expressed (DE) proteins in the hippocampus were identified and analyzed using 4D label-free quantitative proteomics technology and parallel reaction monitoring (PRM). Compared to wild-type mice, 29 proteins were upregulated and 25 proteins were downregulated in the AD group. Gene Ontology (GO) enrichment analysis of biological processes (BP) indicated that the DE proteins were mainly involved in 'ribosomal large subunit biogenesis'. Molecular function (MF) analysis results were primarily associated with '5.8S rRNA binding' and 'structural constituent of ribosome'. In terms of cellular components (CC), the DE proteins were mainly found in 'polysomal ribosome', 'cytosolic large ribosomal subunit', 'cytosolic ribosome', and 'large ribosomal subunit', among others. Furthermore, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis demonstrated that the results were mainly enriched in the 'Ribosome signaling pathway'. The key target proteins identified were ribosomal protein (Rp)l18, Rpl17, Rpl19, Rpl24, Rpl35, and Rpl6. The PRM verification results were consistent with the findings of the 4D label-free quantitative proteomics analysis. Overall, these findings suggest that Rpl18, Rpl17, Rpl19, Rpl24, Rpl35, and Rpl6 may have potential therapeutic value for the treatment of AD by targeting Aβ.

GABAA receptors as plausible molecular targets and mediators for taurine and homotaurine actions

Dementia and autoimmune diseases are prevalent conditions with limited treatment options. Taurine and homotaurine (HT) are naturally occurring sulfonate amino acids, with taurine being highly abundant in animal tissues, but declining with age in the blood. HT is a blood-brain barrier permeable drug under investigation for Alzheimer's disease. HT also has beneficial effects in a mouse model of multiple sclerosis likely through an anti-inflammatory mechanism mediated by GABAA receptor (GABAAR) agonism in immune cells. While both taurine and HT are structural GABA analogs and thought to be GABA mimetics at GABAARs, there is uncertainty concerning their potency as GABA mimetics on native GABAARs. We show that HT is a very potent GABA mimetic, as it evokes GABAAR-mediated currents with an EC50 of 0.4 μM (vs. 3.7 μM for GABA and 116 µM for taurine) in murine cerebellar granule cells in brain slices, with both taurine and HT having similar efficacy in activating native GABAARs. Furthermore, HT displaces the high affinity GABAAR ligand [3H]muscimol at similarly low concentrations (HT IC50 of 0.16 μM vs. 125 μM for taurine) in mouse brain homogenates. The potency of taurine and HT as GABAAR agonists aligns with endogenous concentrations of taurine in the blood and with HT concentrations achieved in the brain following oral administration of HT or the HT pro-drug ALZ-801. Consequently, we discuss that GABAARs subtypes, similar to the ones we studied here in neurons, are plausible targets for mediating the potential beneficial effects of taurine in health and life-span extension and the beneficial HT effects in dementia and autoimmune conditions.

An inclusive study of recent advancements in Alzheimer's disease: A comprehensive review

Alzheimer's disease (AD) has remained elusive in revealing its pathophysiology and mechanism of development. In this review paper, we attempt to highlight several theories that abound about the exact pathway of AD development. The number of cases worldwide has prompted a constant flow of research to detect high-risk patients, slow the progression of the disease and discover improved methods of treatment that may prove effective. We shall focus on the two main classes of drugs that are currently in use; and emerging ones with novel mechanisms that are under development. As of late there has also been increased attention towards factors that were previously thought to be unrelated to AD, such as the gut microbiome, lifestyle habits, and diet. Studies have now shown that all these factors make an impact on AD progression, thus bringing to our attention more areas that could hold the key to combating this disease. This paper covers all the aforementioned factors concisely. We also briefly explore the relationship between mental health and AD, both before and after the diagnosis of the disease.

Clinical trials of new drugs for Alzheimer disease: a 2020-2023 update

Alzheimer's disease (AD) is the leading cause of dementia, presenting a significant unmet medical need worldwide. The pathogenesis of AD involves various pathophysiological events, including the accumulation of amyloid and tau, neuro-inflammation, and neuronal injury. Clinical trials focusing on new drugs for AD were documented in 2020, but subsequent developments have emerged since then. Notably, the US-FDA has approved Aducanumab and Lecanemab, both antibodies targeting amyloid, marking the end of a nearly two-decade period without new AD drugs. In this comprehensive report, we review all trials listed in clinicaltrials.gov, elucidating their underlying mechanisms and study designs. Ongoing clinical trials are investigating numerous promising new drugs for AD. The main trends in these trials involve pathophysiology-based, disease-modifying therapies and the recruitment of participants in earlier stages of the disease. These trends underscore the significance of conducting fundamental research on pathophysiology, prevention, and intervention prior to the occurrence of brain damage caused by AD.

Benzo[d]imidazole-pyrrolo[1,2-a]pyrazine Hybrids Ameliorate Amyloid Aggregates in the Brain of Alzheimer Transgenic Mice

Abnormal assembly of amyloid β (Aβ) in the brain is implicated in Alzheimer's disease (AD) and is associated with cognitive impairments. Since Aβ accumulation occurs in advance of the onset of clinical symptoms, identifying preventable drug candidates regulating Aβ accumulation is regarded as a promising approach in AD therapeutic. Herein, we synthesized eight Yonsei Institute of pharmaceutical sciences Alzheimer's Drug (YIAD) compounds based on 5-benzyl-6-phenylbenzo[4,5]imidazo[1,2-a]pyrrolo[2,1-c]pyrazine structures. Subsequently, YIAD-0203 and YIAD-0205 were selected as effective candidates via thioflavin T assays and gel electrophoresis. The potential therapeutic effect of YIAD-0203 and YIAD-0205 on Aβ aggregates was investigated through an AD transgenic mouse model with five familial AD mutations (5XFAD) by oral gavage. Significant amounts of Aβ plaque and oligomer reduction were observed in the hippocampus region of both 4.3-month-old (early stage of AD) and 6.0-month-old (mid stage of AD) YIAD-0205-treated 5XFAD mice brains when compared to the nontreated brains. The ability of YIAD-0205 to ameliorate Aβ aggregates in the early and mid stages of AD progression supports the notion that YIAD-0205 could be utilized as a reliable scaffold for the development of preventive AD drug candidates.

Does Inflammation Play a Major Role in the Pathogenesis of Alzheimer's Disease?

Alzheimer's disease (AD) is a neurodegenerative disease leading to dementia for which no effective medicine exists. Currently, the goal of therapy is only to slow down the inevitable progression of the disease and reduce some symptoms. AD causes the accumulation of proteins with the pathological structure of Aβ and tau and the induction of inflammation of nerves in the brain, which lead to the death of neurons. The activated microglial cells produce pro-inflammatory cytokines that induce a chronic inflammatory response and mediate synapse damage and the neuronal death. Neuroinflammation has been an often ignored aspect of ongoing AD research. There are more and more scientific papers taking into account the aspect of neuroinflammation in the pathogenesis of AD, although there are no unambiguous results regarding the impact of comorbidities or gender differences. This publication concerns a critical look at the role of inflammation in the progression of AD, based on the results of our own in vitro studies using model cell cultures and other researchers.

Amyloid β-based therapy for Alzheimer's disease: challenges, successes and future

Amyloid β protein (Aβ) is the main component of neuritic plaques in Alzheimer's disease (AD), and its accumulation has been considered as the molecular driver of Alzheimer's pathogenesis and progression. Aβ has been the prime target for the development of AD therapy. However, the repeated failures of Aβ-targeted clinical trials have cast considerable doubt on the amyloid cascade hypothesis and whether the development of Alzheimer's drug has followed the correct course. However, the recent successes of Aβ targeted trials have assuaged those doubts. In this review, we discussed the evolution of the amyloid cascade hypothesis over the last 30 years and summarized its application in Alzheimer's diagnosis and modification. In particular, we extensively discussed the pitfalls, promises and important unanswered questions regarding the current anti-Aβ therapy, as well as strategies for further study and development of more feasible Aβ-targeted approaches in the optimization of AD prevention and treatment.

Domino-like effect of C112R mutation on ApoE4 aggregation and its reduction by Alzheimer's Disease drug candidate

BACKGROUND

Apolipoprotein E (ApoE) ε4 genotype is the most prevalent risk factor for late-onset Alzheimer's Disease (AD). Although ApoE4 differs from its non-pathological ApoE3 isoform only by the C112R mutation, the molecular mechanism of its proteinopathy is unknown.

METHODS

Here, we reveal the molecular mechanism of ApoE4 aggregation using a combination of experimental and computational techniques, including X-ray crystallography, site-directed mutagenesis, hydrogen-deuterium mass spectrometry (HDX-MS), static light scattering and molecular dynamics simulations. Treatment of ApoE ε3/ε3 and ε4/ε4 cerebral organoids with tramiprosate was used to compare the effect of tramiprosate on ApoE4 aggregation at the cellular level.

RESULTS

We found that C112R substitution in ApoE4 induces long-distance (> 15 Å) conformational changes leading to the formation of a V-shaped dimeric unit that is geometrically different and more aggregation-prone than the ApoE3 structure. AD drug candidate tramiprosate and its metabolite 3-sulfopropanoic acid induce ApoE3-like conformational behavior in ApoE4 and reduce its aggregation propensity. Analysis of ApoE ε4/ε4 cerebral organoids treated with tramiprosate revealed its effect on cholesteryl esters, the storage products of excess cholesterol.

CONCLUSIONS

Our results connect the ApoE4 structure with its aggregation propensity, providing a new druggable target for neurodegeneration and ageing.

Study on Absorption, Distribution and Excretion of a New Candidate Compound XYY-CP1106 against Alzheimer's Disease in Rats by LC-MS/MS

XYY-CP1106, a candidate compound synthesized from a hybrid of hydroxypyridinone and coumarin, has been shown to be remarkably effective in treating Alzheimer's disease. A simple, rapid and accurate high-performance liquid chromatography coupled with the triple quadrupole mass spectrometer (LC-MS/MS) method was established in this study to elucidate the pharmacokinetics of XYY-CP1106 after oral and intravenous administration in rats. XYY-CP1106 was shown to be rapidly absorbed into the blood (T_max, 0.57-0.93 h) and then eliminated slowly (T_1/2, 8.26-10.06 h). Oral bioavailability of XYY-CP1106 was (10.70 ± 1.72)%. XYY-CP1106 could pass through the blood-brain barrier with a high content of (500.52 ± 260.12) ng/g at 2 h in brain tissue. The excretion results showed that XYY-CP1106 was mainly excreted through feces, with an average total excretion rate of (31.14 ± 0.05)% in 72 h. In conclusion, the absorption, distribution and excretion of XYY-CP1106 in rats provided a theoretical basis for subsequent preclinical studies.

A near-infrared probe for detecting and interposing amyloid beta oligomerization in early Alzheimer's disease

BACKGROUND

The misfolding and deposition of amyloid beta (Aβ) in human brain is the main hallmark of Alzheimer's disease (AD) pathology. One of the drivers of Alzheimer´s pathogenesis is the production of soluble oligomeric Aβ, which could potentially serve as a biomarker of AD.

METHODS

Given that the diphenylalanine (FF) at the C-terminus of Aβ fragments plays a key role in inducing the AD pathology, based on the hydrophobic structure of FF, we synthesized a near-infrared BF2-dipyrrolmethane fluorescent imaging probe (NB) to detect both soluble and insoluble Aβ.

RESULTS

We found that NB not only binds Aβ, particularly oligomeric Aβ, but also interposes self-assembly of Aβ through π-π interaction between NB and FF.

CONCLUSION

This work holds great promise in the early detection of AD and may also provide an innovative approach to decelerate and even halt AD onset and progression.

Geroscience and Alzheimer's Disease Drug Development

Age is the most important risk factor for Alzheimer's disease (AD). The acceptable age range for participation in AD clinical trials is 50 to 90, and this 40-year span incorporates enormous age-related change. Clinical trial participants tend to be younger and healthier than the general population. They are also younger than the general population of AD patients. Drug development from a geroscience perspective would take greater account of effects of aging on clinical trial outcomes. The AD clinical trial pipeline has diversified beyond the canonical targets of amyloid beta protein and tau. Many of these interventions apply to age-related disorders. Anti-inflammatory agents and bioenergetic and metabolic therapies are among the well represented classes in the pipeline and are applicable to AD and non-AD age-related conditions. Drug development strategies can be adjusted to better inform outcomes of trials regarding aged individuals. Inclusion of older individuals in the multiple ascending dose trials of Phase 1, use of geriatric-related clinical outcomes and biomarkers in Phase 2, and extension of these Phase 2 learnings to Phase 3 will result in a more comprehensive understanding of AD therapies and their relationship to aging. Clinical trials can employ a more comprehensive geriatric assessment approach and biomarkers more relevant to aging at baseline and as exploratory outcomes. Greater attention to the role of aging and its influence in AD clinical trials can result in better understanding of the generalizability of clinical trial findings to the older AD population.

Pharmacotherapy Evolution in Alzheimer's Disease: Current Framework and Relevant Directions

Alzheimer's disease (AD), once considered a rare disease, is now the most common form of dementia in the elderly population. Current drugs (cholinesterase inhibitors and glutamate antagonists) are safe but of limited benefit to most patients, offering symptomatic relief without successful cure of the disease. Since the last several decades, there has been a great need for the development of a treatment that might cure the underlying causes of AD and thereby slow its progression in vulnerable individuals. That is why phase I, II, and III studies that act on several fronts, such as cognitive improvement, symptom reduction, and enhancing the basic biology of AD, are imperative to stop the disease. This review discusses current treatment strategies, summarizing the clinical features and pharmacological properties, along with molecular docking analyses of the existing medications.

Mushroom Natural Products in Neurodegenerative Disease Drug Discovery

The variety of drugs available to treat neurodegenerative diseases is limited. Most of these drug's efficacy is restricted by individual genetics and disease stages and usually do not prevent neurodegeneration acting long after irreversible damage has already occurred. Thus, drugs targeting the molecular mechanisms underlying subsequent neurodegeneration have the potential to negate symptom manifestation and subsequent neurodegeneration. Neuroinflammation is a common feature of neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and multiple sclerosis, and is associated with the activation of the NLRP3 inflammasome, which in turn leads to neurodegeneration. Inflammasome activation and oligomerisation is suggested to be a major driver of disease progression occurring in microglia. With several natural products and natural product derivatives currently in clinical trials, mushrooms have been highlighted as a rich and largely untapped source of biologically active compounds in both in vitro and in vivo neurodegenerative disease models, partially supported by successful clinical trial evaluations. Additionally, novel high-throughput methods for the screening of natural product compound libraries are being developed to help accelerate the neurodegenerative disease drug discovery process, targeting neuroinflammation. However, the breadth of research relating to mushroom natural product high-throughput screening is limited, providing an exciting opportunity for further detailed investigations.

Small-molecule drugs development for Alzheimer's disease

Alzheimer's disease (AD) is an irreversible, progressive neurodegenerative brain disorder with no effective therapeutic drugs currently. The complicated pathophysiology of AD is not well understood, although beta-amyloid (Aβ) cascade and hyperphosphorylated tau protein were regarded as the two main causes of AD. Other mechanisms, such as oxidative stress, deficiency of central cholinergic neurotransmitters, mitochondrial dysfunction, and inflammation, were also proposed and studied as targets in AD. This review aims to summarize the small-molecule drugs that were developed based on the pathogenesis and gives a deeper understanding of the AD. We hope that it could help scientists find new and better treatments to gradually conquer the problems related to AD in future.

Review of Advanced Drug Trials Focusing on the Reduction of Brain Beta-Amyloid to Prevent and Treat Dementia

Alzheimer disease (AD) is the most common neurodegenerative disease and typically affects patients older than age 65. Around this age, the number of neurons begins to gradually decrease in healthy brains, but brains of patients with AD show a marked increase in neuron death, often resulting in a significant loss of cognitive abilities. Cognitive skills affected include information retention, recognition capabilities, and language skills. At present, AD can be definitively diagnosed only through postmortem brain biopsies via the detection of extracellular amyloid beta (Aβ) plaques and intracellular hyperphosphorylated tau neurofibrillary tangles. Because the levels of both Aβ plaques and tau tangles are increased, these 2 proteins are thought to be related to disease progression. Although relatively little is known about the cause of AD and its exact pathobiological development, many forms of treatment have been investigated to determine an effective method for managing AD symptoms by targeting Aβ. These treatments include but are not limited to using small molecules to alter the interactions of Aβ monomers, reducing hyperactivation of neuronal circuits altering Aβ's molecular pathway of synthesis, improving degradation of Aβ, employing passive immunity approaches, and stimulating patients' active immunity to target Aβ. This review summarizes the current therapeutic interventions in Phase II/III of clinical development or higher that are capable of reducing abnormal brain Aβ levels to determine which treatments show the greatest likelihood of clinical efficacy. We conclude that, in the near future, the most promising therapeutic interventions for brain Aβ pathology will likely be passive immunotherapies, with aducanumab and donanemab leading the way, and that these drugs may be combined with antidepressants and acetylcholine esterase inhibitors, which can modulate Aβ synthesis.

Symptomatic and Disease-Modifying Therapy Pipeline for Alzheimer's Disease: Towards a Personalized Polypharmacology Patient-Centered Approach

Since 1906, when Dr. Alois Alzheimer first described in a patient "a peculiar severe disease process of the cerebral cortex", people suffering from this pathology have been waiting for a breakthrough therapy. Alzheimer's disease (AD) is an irreversible, progressive neurodegenerative brain disorder and the most common form of dementia in the elderly with a long presymptomatic phase. Worldwide, approximately 50 million people are living with dementia, with AD comprising 60-70% of cases. Pathologically, AD is characterized by the deposition of amyloid β-peptide (Aβ) in the neuropil (neuritic plaques) and blood vessels (amyloid angiopathy), and by the accumulation of hyperphosphorylated tau in neurons (neurofibrillary tangles) in the brain, with associated loss of synapses and neurons, together with glial activation, and neuroinflammation, resulting in cognitive deficits and eventually dementia. The current competitive landscape in AD consists of symptomatic treatments, of which there are currently six approved medications: three AChEIs (donepezil, rivastigmine, and galantamine), one NMDA-R antagonist (memantine), one combination therapy (memantine/donepezil), and GV-971 (sodium oligomannate, a mixture of oligosaccharides derived from algae) only approved in China. Improvements to the approved therapies, such as easier routes of administration and reduced dosing frequencies, along with the developments of new strategies and combined treatments are expected to occur within the next decade and will positively impact the way the disease is managed. Recently, Aducanumab, the first disease-modifying therapy (DMT) has been approved for AD, and several DMTs are in advanced stages of clinical development or regulatory review. Small molecules, mAbs, or multimodal strategies showing promise in animal studies have not confirmed that promise in the clinic (where small to moderate changes in clinical efficacy have been observed), and therefore, there is a significant unmet need for a better understanding of the AD pathogenesis and the exploration of alternative etiologies and therapeutic effective disease-modifying therapies strategies for AD. Therefore, a critical review of the disease-modifying therapy pipeline for Alzheimer's disease is needed.

Targeted protein degraders march towards the clinic for neurodegenerative diseases

Protein degraders are emerging as potent therapeutic tools to address neurological disorders and many complex diseases. It offered several key advantages, including the doses, drug resistance, and side effects over traditional occupancy-based inhibitors. Translation of chemical degraders into a clinical therapy for neurodegenerative disorders has a well-documented knowledge and resource gap. Researchers strive to develop clinical candidates employing chemical degraders' technologies, including hydrophobic tagging, molecular glues, proteolysis targeting chimeras (PROTACs), specific and nongenetic Inhibitor of Apoptosis Protein (IAP)-dependent protein erasers (SNIPERs), autophagy targeted chimeras, and autophagosome-tethered compounds for targeted degradation of pathological markers in neurodegenerative disease. Herein, we examined the present state of chemical-mediated targeted protein degradation in the quest for medications to treat neurodegenerative diseases. We further identified targeted degraders under clinical development for neurodegenerative diseases summarizing pertinent discoveries guiding the future of degradation therapeutics. We also addressed the necessary pharmacological interventions needed to achieve unprecedented therapeutic efficacy and its associated challenges.

The Small Molecule GAL-201 Efficiently Detoxifies Soluble Amyloid β Oligomers: New Approach towards Oral Disease-Modifying Treatment of Alzheimer’s Disease

Soluble amyloid β (Aβ) oligomers have been shown to be highly toxic to neurons and are considered to be a major cause of the neurodegeneration underlying Alzheimer’s disease (AD). That makes soluble Aβ oligomers a promising drug target. In addition to eliminating these toxic species from the patients’ brain with antibody-based drugs, a new class of drugs is emerging, namely Aβ aggregation inhibitors or modulators, which aim to stop the formation of toxic Aβ oligomers at the source. Here, pharmacological data of the novel Aβ aggregation modulator GAL-201 are presented. This small molecule (288.34 g/mol) exhibits high binding affinity to misfolded Aβ_1-42 monomers (K_D = 2.5 ± 0.6 nM). Pharmacokinetic studies in rats using brain microdialysis are supportive of its oral bioavailability. The Aβ oligomer detoxifying potential of GAL-201 has been demonstrated by means of single cell recordings in isolated hippocampal neurons (perforated patch experiments) as well as in vitro and in vivo extracellular monitoring of long-term potentiation (LTP, in rat transverse hippocampal slices), a cellular correlate for synaptic plasticity. Upon preincubation, GAL-201 efficiently prevented the detrimental effect on LTP mediated by Aβ_1-42 oligomers. Furthermore, the potential to completely reverse an already established neurotoxic process could also be demonstrated. Of particular note in this context is the self-propagating detoxification potential of GAL-201, leading to a neutralization of Aβ oligomer toxicity even if GAL-201 has been stepwise removed from the medium (serial dilution), likely due to prion-like conformational changes in Aβ_1-42 monomer aggregates (trigger effect). The authors conclude that the data presented strongly support the further development of GAL-201 as a novel, orally available AD treatment with potentially superior clinical profile.

α-Synuclein binding activity of the plant growth promoter asterubine

Preventing the aggregation of certain amyloid proteins has the potential to slow down the progression of diseases like Alzheimer's, Parkinson's, and type 2 diabetes mellitus. During a high-throughput screen of 300 Australian marine invertebrate extracts, the extract of the marine sponge Thorectandra sp. 4408 displayed binding activity to the Parkinson's disease-associated protein, α-synuclein. Isolation of the active component led to its identification as the known plant growth promoter asterubine (1). This molecule shares distinct structural similarities with potent amyloid beta aggregation inhibitors tramiprosate (homotaurine) and ALZ-801. Herein we report the isolation, NMR data acquired in DMSO and α-synuclein binding activity of asterubine (1).

Advances in PPARs Molecular Dynamics and Glitazones as a Repurposing Therapeutic Strategy through Mitochondrial Redox Dynamics against Neurodegeneration

Peroxisome proliferator-activated receptors (PPARs) activity has significant implications for the development of novel therapeutic modalities against neurodegenerative diseases. Although PPAR-α, PPAR-β/δ, and PPAR-γ nuclear receptor expressions are significantly reported in the brain, their implications in brain physiology and other neurodegenerative diseases still require extensive studies. PPAR signaling can modulate various cell signaling mechanisms involved in the cells contributing to on- and off-target actions selectively to promote therapeutic effects as well as the adverse effects of PPAR ligands. Both natural and synthetic ligands for the PPARα, PPARγ, and PPARβ/δ have been reported. PPARα (WY 14.643) and PPARγ agonists can confer neuroprotection by modulating mitochondrial dynamics through the redox system. The pharmacological effect of these agonists may deliver effective clinical responses by protecting vulnerable neurons from Aβ toxicity in Alzheimer's disease (AD) patients. Therefore, the current review delineated the ligands' interaction with 3D-PPARs to modulate neuroprotection, and also deciphered the efficacy of numerous drugs, viz. Aβ aggregation inhibitors, vaccines, and γ-secretase inhibitors against AD; this review elucidated the role of PPAR and their receptor isoforms in neural systems, and neurodegeneration in human beings. Further, we have substantially discussed the efficacy of PPREs as potent transcription factors in the brain, and the role of PPAR agonists in neurotransmission, PPAR gamma coactivator-1α (PGC-1α) and mitochondrial dynamics in neuroprotection during AD conditions. This review concludes with the statement that the development of novel PPARs agonists may benefit patients with neurodegeneration, mainly AD patients, which may help mitigate the pathophysiology of dementia, subsequently improving overall the patient's quality of life.

Prodrug Therapies for Infectious and Neurodegenerative Diseases

Prodrugs are bioreversible drug derivatives which are metabolized into a pharmacologically active drug following chemical or enzymatic modification. This approach is designed to overcome several obstacles that are faced by the parent drug in physiological conditions that include rapid drug metabolism, poor solubility, permeability, and suboptimal pharmacokinetic and pharmacodynamic profiles. These suboptimal physicochemical features can lead to rapid drug elimination, systemic toxicities, and limited drug-targeting to disease-affected tissue. Improving upon these properties can be accomplished by a prodrug design that includes the careful choosing of the promoiety, the linker, the prodrug synthesis, and targeting decorations. We now provide an overview of recent developments and applications of prodrugs for treating neurodegenerative, inflammatory, and infectious diseases. Disease interplay reflects that microbial infections and consequent inflammation affects neurodegenerative diseases and vice versa, independent of aging. Given the high prevalence, personal, social, and economic burden of both infectious and neurodegenerative disorders, therapeutic improvements are immediately needed. Prodrugs are an important, and might be said a critical tool, in providing an avenue for effective drug therapy.