BACE1 Research Articles

Modeling and Simulation to Inform Potential New Strategies for BACEi in Treatment of Alzheimers Disease

AbstractBackgroundThe β‐secretase‐1 inhibitors (BACEi), including verubecestat, were extensively studied in prodromal to moderate AD and demonstrated early cognitive decline at doses achieving >50% inhibition of amyloid production. Questions remain as to whether BACEi may still have utility, if used earlier in disease, in combination with other therapies, and/or at lower doses. Modeling and simulation approaches were used to maximize learnings from the prior trials and to make predictions around potential alternative therapeutic approaches.MethodTwo models were developed: 1) A joint plaque turnover model, linking drug exposure with amyloid plaque load (PET data in centiloids), to describe natural progression and treatment response to BACEi and amyloid mAb therapies. All plaque data from natural progression (control arms), BACEi and amyloid mAb treatment arms were well described by a joint model, after accounting for differences in baseline plaque load, dosing and titration regimens, and mechanism of action. 2) Disease progression models for the clinical efficacy outcomes (ADAS‐cog11, CDR‐SB) were developed using a methodology similar to Ref. Evidence for BACEi drug effects (on progression rate and/or early detrimental offset) was tested and dependencies on dose, drug exposure and patient characteristics were explored.ResultThe joint plaque turnover model well described natural progression and treatment response to BACEi and amyloid mAb and allows for prediction of alternative regimens and therapeutic approaches. Simulations indicate that 20‐30% inhibition of BACE would be sufficient to stabilize plaque loads in prodromal patients. Disease progression results for ADAS‐cog11 and CDR‐SB identified a verubecestat drug effect of early detrimental offset with no effect on rate of disease progression supported. The magnitude of the early detrimental offset was small relative to the overall progression seen over 18‐24 months and results suggested that this effect may be reduced in advanced AD patients. A simulation engine utilizing the progression model allows for estimation of sample size needed to check for the detrimental effect in future trials.ConclusionModel‐based simulations can help inform future BACEi therapeutic strategies and trial designs. Reference: Clin Pharmacol Ther. 2015 Mar;97(3):210‐4

Novel Bace 1 selective inhibitor does not affect dendritic spine plasticity

AbstractBackgroundAll clinical BACE‐inhibitor trials for the treatment of Alzheimer´s Disease have failed due to insufficient efficacy or side effects like worsening of cognitive symptoms. The latter could have been the result of the inhibition of BACE at the synapse where it is expressed in high amounts. We have previously shown that prolonged inhibition of BACE interferes with structural and functional synaptic plasticity (Filser et al. Biol. Psych 2015, Blume et al. Front. Aging Neurosci. 2018), most likely due to the diminished processing of the physiological BACE substrate Seizure protein 6 (Sez6, Zhu et al. Biol. Psych. 2018), which is exclusively processed by BACE1 and it is required for dendritic spine plasticity. The aim of the current study was to elucidate the effects of selective BACE1 inhibitors on dendritic spine plasticity at a dose that affects Sez6 cleavage to various degrees but not completely.MethodBy using longitudinal in vivo two‐photon microscopy, we investigated the effect on dendritic spine dynamics of pyramidal layer V neurons in the somatosensory cortex in mice treated with 2 novel highly selective BACE1 inhibitors developed at Shionogi in comparison to Elenbecestat which reduce soluble Sez6 to 27% (Elenbecastat), 17% (Shionogi Compound 1) and 39% (Shionogi Compound2) of baseline levels in untreated animals. For the detection of the soluble Sez6 ectodomain, the BACE cleavage product from full‐length Sez6, Western blot analysis was performed using a highly specific Sez6 antibody generated in the lab of Stefan Lichtenthaler (Pigoni et al. Mol. Neurodeg. 2016).ResultWe observed that BACE1 selective inhibitors do not alter dendritic spine density and plasticity in cortical neurons if at least 27% of soluble Sez6 remains. In detail, the density of gained and lost spines does not change under the treatment with Shionogi Compound 2 or Elenbecastat. Also, no differences in the stability of dendritic spines were found during treatment with these two compounds. With Compound 1 however, a significant spine loss occurs after 21 days of treatment.ConclusionSelective BACE1 inhibitors do not alter dendritic spine plasticity in mice if dosing reduces synaptic BACE1 cleavage of Sez6 not below 27% of baseline soluble Sez6 levels. BACE1 selective inhibitors may be potential novel candidates for clinical trials treating AD if dosing is carefully adjusted to the amount of Sez6 cleavage, which can be easily monitored during the first weeks of treatment.

Anti‐mouse CD98hc nanobodies for brain delivery of a therapeutic moiety

AbstractBackgroundThe blood‐brain barrier (BBB) limits the therapeutic perspective for central nervous system (CNS) disorders such as Alzheimer’s disease. Interestingly, monoclonal antibodies generated against receptor‐mediated transcytosis receptors are able to transport therapeutic proteins across the BBB. Nanobodies, which are the variable domain isolated from camelid heavy‐chain only antibodies have also shown their potential to deliver therapeutics into the CNS. Here we aimed to expand the panel of nanobodies targeting other brain endothelial cell receptors.MethodCamelids were immunized with a pool of DNA encoding for several brain endothelial cell receptors. One target was chosen to validate the immunization and discovery approach, CD98hc, previously suggested to allow drug shuttling across the BBB. Nanobody libraries were selected on Chinese Hamster Ovarian (CHO) cells overexpressing the target of interest. Selected nanobodies were screened in vivo based on their potential to deliver into the CNS either a biologically active neuropeptide neurotensin to reduce body temperature, or a BACE1 inhibiting antibody that reduces the accumulation of Aβ1‐40 species.ResultDNA immunization followed by selections on CHO cells overexpressing the target of interest resulted in specific anti‐mouse CD98hc binders with affinities in the low nanomolar range. In vivo screening of mouse CD98hc nanobody binders revealed some discrepancy between the two methods used. Whereas none of the tested nanobodies fused to neurotensin was able to reduce body temperature, nanobodies fused to the anti‐BACE1 antibody 1A11 effectively reduced Aβ1‐40 levels in the brain. We suggest that the neurotensin approach, although having shown robustness with anti‐TfR nanobodies, might lack sensitivity when screening non‐TfR binders. We suggest BACE1 inhibition as a more robust model to validate CD98hc‐mediated transport across the BBB.ConclusionThis is a proof of concept study in which we have optimized our nanobody discovery approach to find nanobodies against BBB targets, and validated CD98hc as a receptor to target in order to shuttle drugs into the brain. In the future we will explore whether nanobodies raised against novel brain endothelial cell receptors could also improve brain penetration of biologics.

Neuroprotective Effects of N-methyl-(2S, 4R)-trans-4-hydroxy-L-proline (NMP) against Amyloid-β-Induced Alzheimer’s Disease Mouse Model

Alzheimer’s disease (AD), is a progressive neurodegenerative disorder that involves the deposition of β-amyloid plaques and the clinical symptoms of confusion, memory loss, and cognitive dysfunction. Despite enormous progress in the field, no curative treatment is available. Therefore, the current study was designed to determine the neuroprotective effects of N-methyl-(2S, 4R)-Trans-4-hydroxy-L-proline (NMP) obtained from Sideroxylon obtusifolium, a Brazilian folk medicine with anti-inflammatory and anti-oxidative properties. Here, for the first time, we explored the neuroprotective role of NMP in the Aβ1–42-injected mouse model of AD. After acclimatization, a single intracerebroventricular injection of Aβ1–42 (5 µL/5 min/mouse) in C57BL/6N mice induced significant amyloidogenesis, reactive gliosis, oxidative stress, neuroinflammation, and synaptic and memory deficits. However, an intraperitoneal injection of NMP at a dose of (50 mg/kg/day) for three consecutive weeks remarkably decreased beta secretase1 (BACE-1) and Aβ, activated the astrocyte and microglia expression level as well as downstream inflammatory mediators such as pNF-ĸB, TNF-α, and IL-1β. NPM also strongly attenuated oxidative stress, as evaluated by the expression level of NRF2/HO-1, and synaptic failure, by improving the level of both the presynaptic (SNAP-25 and SYN) and postsynaptic (PSD-95 and SNAP-23) regions of the synapses in the cortexes and hippocampi of the Aβ1–42-injected mice, contributing to cognitive improvement in AD and improving the behavioral deficits displayed in the Morris water maze and Y-maze. Overall, our data suggest that NMP provides potent multifactorial effects, including the inhibition of amyloid plaques, oxidative stress, neuroinflammation, and cognitive deficits.

Views and perceptions of amyloid imaging in a preclinical Alzheimer’s disease trial

AbstractBackgroundStudies have shown that many cognitively unimpaired older individuals are interested in learning their Alzheimer’s disease (AD) biomarker results. Yet, little is known about what motivates participation in preclinical AD trials that require amyloid biomarker testing and disclosure, and whether these motivations differ by biomarker results (elevated or not‐elevated amyloid).MethodUsing data from the EARLY trial, a preclinical AD trial testing the safety and efficacy of a BACE1 inhibitor, we analyzed participant responses on the Views and Perceptions of Amyloid Imaging (VPAI) scale (Table 1) that was collected during the screening process; that is, before undergoing biomarker testing and disclosure. Participants were asked to rate how important 9 potential reasons for seeking amyloid imaging were to them. Response options included “not at all” (1), “a little” (2), “somewhat” (3), “very” (4), and “extremely” (5). We categorized raw scores into binary responses; those with high endorsement (scores ≥4) and those with low‐to‐moderate endorsement (scores <4). We stratified participant responses by amyloid group to examine whether their biomarker status impacted participant item‐level VPAI scores.ResultPrior to biomarker testing and disclosure, participants most often endorsed the desire to contribute to research as a motivation to participate (Table 1). In general, the not‐elevated amyloid group had higher endorsement for the VPAI items than the elevated amyloid group. The proportions of participants endorsing “confirm feeling that I might be developing dementia” and “preparing family members” were observed to be higher among participants with elevated compared to not‐elevated amyloid; whereas “curiosity” was endorsed by a higher proportion of the not‐elevated amyloid group.ConclusionWhile there are individual differences in reasons for seeking an amyloid scan, preclinical AD trial participants may be largely motivated by altruistic factors. Differences in factors that motivate participants to learn biomarker results may be apparent between amyloid groups even before biomarker disclosure.

Pooled Modeling of Disease Progression in Two BACE1 Inhibitor Verubecestat Trials in Prodromal to Moderate Alzheimer’s Disease

AbstractBackgroundThe BACE inhibitor verubecestat (MK‐8931) at doses of 12 and 40 mg demonstrated cognitive and functional decline relative to placebo in a Phase 3 trial of prodromal AD (APECS, NCT01953601) and no effect on progression in a Phase 3 trial of mild‐to‐moderate AD (EPOCH, NCT01739348). Disease progression modeling was used to investigate the temporal pattern of the cognitive and functional drug effects and to explore covariate, dose‐ or exposure‐dependency in the pooled data from both trials. The key objective was to determine whether the rate of progression was slowed by BACEi but obscured by an early detrimental drug effect.MethodDisease progression models for the clinical efficacy outcomes (ADAS‐cog11, CDR‐SB) were developed using similar methodology to an established ADAS‐cog disease progression model (Ref). Parameters describing placebo response were first estimated. Akaike Information Criteria (AIC) were then used to select among potential drug effects (effects on progression rate and/or early detrimental offset) and to test for dependencies on dose, drug exposure, and patient characteristics. A simulation exercise confirmed that a true 25% or 50% reduction in the progression rate with treatment could be reliably identified in the setting of the early detrimental effect.ResultResults were generally concordant across ADAS‐cog11 and CDR‐SB. An early symptomatic (detrimental offset) response was identified with verubecestat; no effect on rate of disease progression was supported. The magnitude of the drug effect offset was estimated 1.8 for ADAS‐cog11 and 0.33 for CDR‐SB. Covariates were generally concordant across measures with disease severity at baseline identified for both progression rate and detrimental offsetting. Additionally, age, weight, geographic region, and education effects were identified on progression. Threshold analysis of the detrimental offsetting effect suggested that the effect was present in less severe disease but absent in the most advanced AD patients (ADAS‐cog11 baseline>24 and CDR‐SB baseline > = 12).ConclusionNo dose or AUC dependency on the detrimental offsetting effect of verubecestat was found, indicating that the maximum effect is achieved at 12 and 40 mg doses. There was no evidence supporting a slowed rate of disease progression by BACEi after accounting for the early detrimental drug effect.

Neuropathological changes of a patient with AD treated with verubecestat

AbstractBackgroundClinical trials with BACE‐1 inhibitors in patients with Alzheimer’s disease (AD) have been discontinued due to safety concerns. The adverse effects included reversible early cognitive worsening and brain atrophy. Some data suggest that these effects could be due to an off‐target effect of the inhibitor on other BACE‐1 substrates that could impact synaptic function and structure. However, the precise underlying mechanisms of these effects in humans remain controversial.MethodWe describe the neuropathological examination of a patient with AD treated for 38 months with low doses of the BACE‐1 inhibitor verubecestat.ResultBrain examination showed small plaque size, reduced dystrophic neurites around plaques, and reduced synaptic‐associated Aβ compared with a group of age‐matched untreated sporadic AD (SAD) cases. We also describe a detailed analysis of synaptic morphology in this case.ConclusionOur findings suggest that BACE‐1 inhibition has an impact on synaptic soluble Aβ accumulation and neuritic derangement in AD. Neuropathological data could help to understand the effect of BACE inhibition in humans.

Anti‐amyloidogenic effect of BACE1 expression lowering compound identified using high‐throughput gene promoter assay

AbstractBackgroundAccumulation of Aβ in a brain is one of the pathological hallmarks of Alzheimer’s disease (AD). Aβ is generated through sequential cleavage of amyloid precursor protein (APP) by β‐secretase (BACE1) and γ‐secretase complex. BACE1 is one of the crucial targets for AD given that BACE1 expression is significantly upregulated in AD patients compared with non‐AD. However, direct and complete inhibition of BACE1 activity can cause unpredictable or unintended effects because of numerous physiological substrates of BACE1.MethodWe screened small compounds, including drugs approved by the U.S. Food and Drug Administration to identify medicines that reduce promoter activity of BACE1. TG reduced the levels of BACE1 protein and mRNA in APP‐SH‐SY5Y cells. In order to confirm the effect of TG regulating the expression BACE1, we constructed the RFP (BACE1 expression indicator) ‐GFP (cell body) U2OS cell line and compared the TG and analogs. After administration of TG,we carried out Morris Water Maze(MWM) test in APP/PS1 AD model mice. We did immunofluorescence assay in each group of mouse brains. We conducted an ELISA assay to determine quantitative changes in Aβ accumulation.ResultWe have found a new candidate drug that reduces promoter activity, mRNA, and protein levels of BACE1 in neuronal cells. We have confirmed that the drug decreases the BACE1 gene expression, prevents accumulation of Aβ, and improves cognitive function in APP/PS1 transgenic mice.ConclusionThe ability of this compound reverses a wide range of deficits suggests that BACE1 expression reducing agents may have therapeutic utility in the treatment of AD

Single crystal X-ray, DFT, molecular dynamic simulations, and biological evaluation of 3-OH pyrrolidine derivative VA10 from alkaloid vasicine for BACE1 inhibition

Alzheimer's is a progressive neurodegenerative disease with amyloid-beta peptide deposition that impairs memory and cognitive decline. Due to lack of effective treatment for Alzheimer's disease (AD), there is an interest in finding novel compounds to treat AD. The alkaloid vasicine derivative VA10 inhibited cholinesterases and amyloid beta aggregation in Alzheimer induced rats and showed multi-target activity in treating AD. Therefore, the present study uses single-crystal X-ray and DFT studies to evaluate the properties of VA10′s physicochemical properties, reactivity, and stability. Further, the scaffold VA10 was assessed through in silico, in vitro BACE1 inhibition, and in vivo CNS toxicity experiments. The VA10 Hirshfeld surface analysis and fingerprint plots were determined to understand intra and intermolecular interactions. Furthermore, HOMO-LUMO, UV, and IR studies investigated the electrical and vibrational characteristics. The molecular docking and molecular dynamics simulation studies revealed that compound VA10 formed key interactions with active site amino acid residues and well resided at the BACE1 active site. The VA10 was found to be a potent BACE1 inhibitor and showed no sign of toxicity in rats up to 50 mg/kg. The study identifies VA10, a vasicine derivative, as a possible BACE1 inhibitor in treating Alzheimer's disease. Furthermore, comparing experimental and theoretical results may be beneficial in evaluating VA10′s molecular interactions and reactivity.

Development of Potential Multi-Target Inhibitors for Human Cholinesterases and Beta-Secretase 1: A Computational Approach.

Alzheimer's disease causes chronic neurodegeneration and is the leading cause of dementia in the world. The causes of this disease are not fully understood but seem to involve two essential cerebral pathways: cholinergic and amyloid. The simultaneous inhibition of AChE, BuChE, and BACE-1, essential enzymes involved in those pathways, is a promising therapeutic approach to treat the symptoms and, hopefully, also halt the disease progression. This study sought to identify triple enzymatic inhibitors based on stereo-electronic requirements deduced from molecular modeling of AChE, BuChE, and BACE-1 active sites. A pharmacophore model was built, displaying four hydrophobic centers, three hydrogen bond acceptors, and one positively charged nitrogen, and used to prioritize molecules found in virtual libraries. Compounds showing adequate overlapping rates with the pharmacophore were subjected to molecular docking against the three enzymes and those with an adequate docking score (n = 12) were evaluated for physicochemical and toxicological parameters and commercial availability. The structure exhibiting the greatest inhibitory potential against all three enzymes was subjected to molecular dynamics simulations (100 ns) to assess the stability of the inhibitor-enzyme systems. The results of this in silico approach indicate ZINC1733 can be a potential multi-target inhibitor of AChE, BuChE, and BACE-1, and future enzymatic assays are planned to validate those results.

Identification of Potential Multitarget Compounds against Alzheimer's Disease through Pharmacophore-Based Virtual Screening.

Alzheimer's disease (AD) is a neurodegenerative disease characterized by progressive loss of cognitive functions, and it is the most prevalent type of dementia worldwide, accounting for 60 to 70% of cases. The pathogenesis of AD seems to involve three main factors: deficiency in cholinergic transmission, formation of extracellular deposits of β-amyloid peptide, and accumulation of deposits of a phosphorylated form of the TAU protein. The currently available drugs are prescribed for symptomatic treatment and present adverse effects such as hepatotoxicity, hypertension, and weight loss. There is urgency in finding new drugs capable of preventing the progress of the disease, controlling the symptoms, and increasing the survival of patients with AD. This study aims to present new multipurpose compounds capable of simultaneously inhibiting acetylcholinesterase (AChE), butyrylcholinesterase (BChE)-responsible for recycling acetylcholine in the synaptic cleft-and beta-secretase 1 (BACE-1)-responsible for the generation of amyloid-β plaques. AChE, BChE, and BACE-1 are currently considered the best targets for the treatment of patients with AD. Virtual hierarchical screening based on a pharmacophoric model for BACE-1 inhibitors and a dual pharmacophoric model for AChE and BChE inhibitors were used to filter 214,446 molecules by QFITBACE > 0 and QFITDUAL > 56.34. The molecules selected in this first round were subjected to molecular docking studies with the three targets and further evaluated for their physicochemical and toxicological properties. Three structures: ZINC45068352, ZINC03873986, and ZINC71787288 were selected as good fits for the pharmacophore models, with ZINC03873986 being ultimately prioritized for validation through activity testing and synthesis of derivatives for SAR studies.

Oxidative Stress and Natural Antioxidants: Back and Forth in the Neurological Mechanisms of Alzheimer's Disease.

Alzheimer's disease (AD) is characterized by the progressive degeneration of neuronal cells. With the increase in aged population, there is a prevalence of irreversible neurodegenerative changes, causing a significant mental, social, and economic burden globally. The factors contributing to AD are multidimensional, highly complex, and not completely understood. However, it is widely known that aging, neuroinflammation, and excessive production of reactive oxygen species (ROS), along with other free radicals, substantially contribute to oxidative stress and cell death, which are inextricably linked. While oxidative stress is undeniably important in AD, limiting free radicals and ROS levels is an intriguing and potential strategy for deferring the process of neurodegeneration and alleviating associated symptoms. Therapeutic compounds from natural sources have recently become increasingly accepted and have been effectively studied for AD treatment. These phytocompounds are widely available and a multitude of holistic therapeutic efficiencies for treating AD owing to their antioxidant, anti-inflammatory, and biological activities. Some of these compounds also function by stimulating cholinergic neurotransmission, facilitating the suppression of beta-site amyloid precursor protein-cleaving enzyme 1, α-synuclein, and monoamine oxidase proteins, and deterring the occurrence of AD. Additionally, various phenolic, flavonoid, and terpenoid phytocompounds have been extensively described as potential palliative agents for AD progression. Preclinical studies have shown their involvement in modulating the cellular redox balance and minimizing ROS formation, displaying them as antioxidant agents with neuroprotective abilities. This review emphasizes the mechanistic role of natural products in the treatment of AD and discusses the various pathological hypotheses proposed for AD.

Evaluation of F3S4-m loaded liposomes as anti-AChE and its cytotoxic activity in PC12 and HMC3 cells

The current research discusses the loaded of F3S4-m compound reported with multitarget activity acting as an inhibitor of acetylcholinesterase (AChE), beta-secretase 1 (BACE1), and amyloid beta (Aβ) aggregation. Despite great effort has been done to have a compound to treat Alzheimer’s disease (AD) and not only its symptomatology, nowadays there is not an effective compound in the market yet. Several synthetized compounds reported having a good activity in vitro study turned out not having it in vivo, it is believed that many of them are not able to reach the brain due to low biodisponibility, besides many of them have charged chemicals groups or tertiary amines, which have been substrates of deaminases enzymes. Therefore, the use of liposomes results an interesting strategy to deliver this kind of compounds to the brain. Then in this work it is proposed the use flexible liposomes made from phosphatidylcholine (PC) and cholesterol (Chol) to encapsulate the F3S4-m compound and evaluate its inhibitory activity against AChE. The results showed that empty liposomes particle size is influenced by the content of cholesterol in their membranes being larger for those containing 20% of cholesterol than those with 10%. The toxicity of F3S4-m loaded liposomes in PC12 cells was also evaluated employing the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay (MTT). The results showed that F3S4-m loaded liposomes can inhibit the enzymatic activity of AChE, but the concentration of encapsulated F3S4-m needed to inhibit AChE was 2-times higher than what was previously reported in solution.Graphical abstract

Hesperidin Methyl Chalcone reduces extracellular Aβ(25-35) peptide aggregation and fibrillation and also protects Neuro 2a cells from Aβ(25-35) induced neuronal dysfunction

In the present study, we evaluated the neuroprotective potential of Hesperidin Methyl Chalcone (HMC) against the neurotoxicity induced by Aβ(25-35) peptide. HMC demonstrated higher free-radical scavenging activity than Hesperidin in initial cell-free studies. Investigations using the fluorescent dye thioflavin T with Aβ(25-35) peptide showed that HMC has the ability to combat extracellular amyloid aggregation by possessing anti-aggregation property against oligomers and by disaggregating mature fibrils. Also, the results of the molecular simulation studies show that HMC ameliorated oligomer formation. Further, the anti-Alzheimer’s property of HMC was investigated in in vitro cell conditions by pre-treating the neuro 2a (N2a) cells with HMC before inducing Aβ(25-35) toxicity. The findings demonstrate that HMC increased cell viability, reduced oxidative stress, prevented macromolecular damage, allayed mitochondrial dysfunction, and exhibited anticholinesterase activity. HMC also reduced Aβ induced neuronal cell death by modulating caspase-3 activity, Bax expression and Bcl2 overexpression, demonstrating that HMC pre-treatment reduced mitochondrial damage and intrinsic apoptosis induced by Aβ(25-35).In silico evaluation against potential AD targets reveal that HMC could be a potent inhibitor of BACE-1, inhibiting the formation of toxic Aβ peptides. Overall, the findings imply that the neuroprotective efficacy of HMC has high prospects for addressing a variety of pathogenic consequences caused by amyloid beta in AD situations and alleviating cognitive impairments.

Multifunctional agents against Alzheimer’s disease based on oxidative stress: Polysubstituted pyrazine derivatives synthesized by multicomponent reactions

As Alzheimer’s disease (AD) is a neurodegenerative disease with a complex pathogenesis, the exploration of multi-target drugs may be an effective strategy for AD treatment. Multifunctional small molecular agents can be obtained by connecting two or more active drugs or privileged pharmacophores by multicomponent reactions (MCRs). In this paper, two series of polysubstituted pyrazine derivatives with multifunctional moieties were designed as anti-AD agents and synthesized by Passerini-3CR and Ugi-4CR. Since the oxidative stress plays an important role in the pathological process of AD, the antioxidant activities of the newly synthesized compounds were first evaluated. Subsequently, selected active compounds were further screened in a series of AD-related bioassays, including Aβ1-42 self-aggregation and deaggregation, BACE-1 inhibition, metal chelation, and protection of SH-SY5Y cells from H2O2-induced oxidative damage. Compound A3B3C1 represented the best one with multifunctional potencies. Mechanism study showed that A3B3C1 acted on Nrf2/ARE signaling pathway, thus increasing the expression of related antioxidant proteins NQO1 and HO-1 to normal cell level. Furthermore, A3B3C1 showed good in vitro human plasma and liver microsome stability, indicating a potential for further development as multifunctional anti-AD agent.

Anti-Alzheimer potential of coumarin derivatives: A review

Alzheimer’s is a type of neurodegenerative diseases (NDs) found in old age people which main causes the dementia and various brain disorders. FDA approved drugs used commonly in treatment of moderate to severe Alzheimer's disease are Donepezil, Rivastigmine, Galantamine and Memantine. However, these approved drugs provide only palliative support not complete cure. So, urgency of new molecules has been becoming so important to cure this complex Disease. Coumarin or 2-H-Chromen-2-one is an oxygenated heterocyclic compound, which is isolated from plants named Dipteryx odorata Willd, (Fabaceae). Synthetic coumarin derivatives has been well presence in literature due to existence of their potential pharmacological activities in literature. This review covers the anti-Alzheimer activities of chemically synthesized coumarin derivatives from 2016-2023. Coumarin derivatives profound found exhibits potential anti-Alzheimer activities in literature. Coumarin derivatives showed their anti-Alzheimer potential through various pharmacological pathways such as monoamine oxidase (MAO) inhibitor, acetylcholinesterase (AChE) & Butyl cholinesterase (BuChE) inhibitory activity, Aβ amyloid inhibition, Beta secretase 1 (BACE1 inhibitors). Multi-target directed ligands (MTDLs) approach also extensively reported to design and synthesis of novel coumarin scaffold as potential multifunctional Anti-Alzheimer activities in last one decade. We also covered literature of some coumarin hybrids derivatives as potential Anti-Alzheimer activities. Some common synthetic methods of coumarin structure also covered in this review article. This review supported that coumarin derivatives found excellent anti-Alzheimer activities and it can be play major role to solve the problem of complex AD disease.

Networkodynamic approach to perceive the key phytoconstituents of E. officinalis (Amla) as natural BACE1 inhibitors: an in-silico study

Alzheimer’s disease (AD) is a deteriorating neural disorder, and currently, available drugs are ineffective in its treatment. Emblica officinalis (Amla) is widely recognised in the Indian medicinal system for ameliorative effects in managing diabetes, hyperlipidaemia and neurological diseases. Thus, we aimed to identify the active phytoconstituents of E. officinalis and their role in inhibiting the potential targets for the possible treatment of AD. The network pharmacology approach, gene ontology, molecular docking and molecular dynamics simulation (MDS) studies were performed. A total of 36 bioactive components in E. officinalis, 95 predicted anti-AD targets, and 3398 AD-related targets were identified from different databases. The network analysis showed that BACE1, ABCB1 and AChE, CA2 are the most potential AD targets. Based on gene ontology and topology analysis results, BACE1 was a significant target related to AD pathways, and quercetin, kaempferol and myricetin showed the highest interaction with target genes. The molecular docking results found that rutin and quercetin displayed better binding affinities −7.5, −5.67 kcal/mol than the BACE1 bound internal ligand. Furthermore, MDS results suggested that quercetin and rutin could be potential inhibitors against BACE-1 protein and may have therapeutic effects in treating AD. Such promising results could be further helpful in new drug discovery against AD. Communicated by Ramaswamy H. Sarma

Cyanobacterial metabolites as novel inhibitors of BACE1 implicated in Alzheimer's disease through in silico approaches

Alzheimer's disease (AD) is a complex neurodegenerative disease with a limited number of therapeutic options. β-Secretase 1 (BACE1) is a key enzyme involved in the production of amyloid beta peptides, which are central to AD pathology. Targeting BACE1 has emerged as a promising strategy for the treatment of AD. Therefore, the present study aimed to discover novel drug candidates from cyanobacteria for the treatment of AD through in silico research. In this study, Schrödinger tools were used to study the binding affinities and interactions of cyanobacteria metabolites with BACE1. Almost 120 cyanobacteria metabolites against BACE1 were used for the computational investigation. Ultimately, four marine-derived compounds, namely lyngbyastatin 7, homodolastin 3, lyngbyabellin E1, and symplostatin analogue 4, showed strong binding affinities to the active site of BACE1, forming crucial hydrogen bonds and hydrophobic interactions. The binding energy values of these compounds suggest their potential as BACE1 inhibitors. Furthermore, molecular dynamics simulations confirmed the stability of these ligand-protein complexes over a period of 25 ​ns? Our results provide valuable insights into the potential of lyngbyastatin 7, homodolastin 3, lyngbyabellin E1, and symplostatin analog 4 as effective drugs for inhibiting BACE1. These marine-derived compounds are promising for further in vitro and in vivo studies. The present research suggests that these molecules could offer new avenues for the development of novel therapeutics for the treatment of Alzheimer's disease.

Screening of Multitarget-Directed Natural Compounds as Drug Candidates for Alzheimer's Disease Using In Silico Techniques: Their Extraction and In Vitro Validation.

Alzheimer's disease (AD) is a neurodegenerative disorder that impairs neurocognitive function. Acetylcholinesterase (AChE) and β-site APP cleaving enzyme 1 (BACE1) are the two main proteins implicated in AD. Indeed, the major available commercial drugs (donepezil, rivastigmine, and galantamine) against Alzheimer's are AChE inhibitors. However, none of these drugs are known to reverse or reduce the pathophysiological condition of the disease since there are multiple contributing factors to AD. Therefore, there is a need to develop a multitarget-directed ligand approach for its treatment. In the present study, plant bioactive compounds were screened for their AChE and BACE1 inhibition potential by conducting molecular docking studies. Considering their docking score and pharmacokinetic properties, limonin, peimisine, serratanine B, and withanolide A were selected as the lead compounds. Molecular dynamics simulations of these protein-ligand complexes confirmed the conformational and energetically stabilized enzyme-inhibitor complexes. The inhibition potential of the lead compounds was validated by in vitro enzyme assay. Withanolide A inhibited AChE (IC50 value of 107 μM) and showed mixed-type inhibition. At this concentration, it inhibited BACE1 activity by 57.10% and was stated as most effective. Both the compounds, as well as their crude extracts, were found to have no cytotoxic effect on the SH-SY5Y cell line.

Identifying β-secretase 1 (BACE1) inhibitors from plant-based compounds: an approach targeting Alzheimer's therapeutics employing molecular docking and dynamics simulation.

β-secretase 1 (BACE1) is an enzyme that is involved in generating beta-amyloid peptides and is believed to have a significant role in the development of Alzheimer's disease (AD). Therefore, BACE1 has gained attention as a potential therapeutic target for treating AD. Modern drug discovery studies are being conducted to identify potential inhibitors of BACE1, with the goal of reducing the production of beta-amyloid peptides and, thus, slowing the progression of AD. Here, we used a multistep virtual screening methodology to identify phytoconstituents from the IMPPAT library that could inhibit the activity of BACE1. Molecular docking was employed to select initial hits based on their binding affinity toward BACE1. Screening for PAINS patterns, ADMET and PASS properties, was then used to identify potential molecules for BACE1 inhibition. In the end, we discovered two natural compounds, Peiminine and 27-Deoxywithaferin A, which demonstrated a strong affinity, effectiveness, and specific interactions for the BACE1-active site. The elucidated molecules also displayed drug likeliness. A 200ns molecular dynamics (MD) simulation was conducted to investigate the interaction mechanism, complex stability, and conformational dynamics of BACE1 with Peiminine and 27-Deoxywithaferin A. The MD simulations demonstrated that BACE1 was stable during the simulation with Peiminine and 27-Deoxywithaferin A. Overall, the results suggested that Peiminine and 27-Deoxywithaferin A hold significant potential as scaffolds in drug development efforts targeting BACE1 for the purpose of treating AD.