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Background: Due to complex pathogenesis of Alzheimer's disease (AD), currently there is no effective disease-modifying treatment. Acetylcholinesterase (AChE) has introduced itself as an important target for AD therapy. Linarin as the representative active ingredient of flavonoid glycoside in Flos chrysanthemi indici has been found to have anti-acetylcholinesterase effect., Aims: The present study intended to explore the potential effect of linarin for treatment of AD., Main Methods: In this study, molecular docking simulation was used to evaluate whether linarin could dock with AChE and decipher the mechanism of linarin as an AChE inhibitor. After molecular docking simulation, AlCl 3 -induced Alzheimer's disease zebrafish model was established. Effects of linarin on treating AD zebrafish dyskinesia and AChE inhibition were compared with donepezil (DPZ) which was used as a positive control drug., Key Findings: Molecular docking simulation showed that linarin plays a critical role in AChE inhibition by binding AChE active sites. The experiments illustrated that the dyskinesia recovery rate of AD zebrafish could be significantly improved by linarin. The dyskinesia recovery and AChE inhibition rate were 88.0% and 74.5% respectively, while those of DPZ were 79.3% and 43.6%., Significance: These findings provide evidences for supporting linarin to be developed into an AD drug by inhibiting the activity of AChE., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Complex I (NADH dehydrogenase, NDU) and complex IV (cytochrome-c-oxidase, COX) of the mitochondrial electron transport chain have been implicated in the pathophysiology of major psychiatric disorders, such as major depressive disorder (MDD), bipolar disorder (BD), and schizophrenia (SZ), as well as in neurodegenerative disorders, such as Alzheimer disease (AD) and Parkinson disease (PD). We conducted meta-analyses comparing complex I and IV in each disorder MDD, BD, SZ, AD, and PD, as well as in normal aging. The electronic databases Pubmed, EMBASE, CENTRAL, and Google Scholar, were searched for studies published between 1980 and 2018. Of 2049 screened studies, 125 articles were eligible for the meta-analyses. Complex I and IV were assessed in peripheral blood, muscle biopsy, or postmortem brain at the level of enzyme activity or subunits. Separate meta-analyses of mood disorder studies, MDD and BD, revealed moderate effect sizes for similar abnormality patterns in the expression of complex I with SZ in frontal cortex, cerebellum and striatum, whereas evidence for complex IV alterations was low. By contrast, the neurodegenerative disorders, AD and PD, showed strong effect sizes for shared deficits in complex I and IV, such as in peripheral blood, frontal cortex, cerebellum, and substantia nigra. Beyond the diseased state, there was an age-related robust decline in both complexes I and IV. In summary, the strongest support for a role for complex I and/or IV deficits, is in the pathophysiology of PD and AD, and evidence is less robust for MDD, BD, or SZ.

Alzheimer's is a neural disorder causing gradual loss in structure and function of nerve cell. To treat such disorders, c-Jun N-terminal Kinase (JNK) Pathway inhibitors were developed by representing chemical compounds that were used to inhibit the JNK signaling pathways. DLK is the stress sensor and implicating as regulatory factor in JNK pathway. Therefore, in the present investigation, pharmacophore screening was tried to identify the chemical compounds that involving inhibition of DLK proteins. To explore the pharmacophore region and mode of binding with DLK protein, N- (I H-pyrazol-3-y l) pyridin-2-aminer inhibitors were docked with DLK. Results reveal the information on the interaction mechanism of protein and ligand with chemical characteristics required to inhibit DLK protein. Such predicted information (AAAARH) was used as query to find out potential novel lead compounds sourced from public database. As an outcome of 65 compounds were listed based on the fitness score (2≥), and were subjected to glide HTVS.SP and XP. Best performing 5 lead compounds were shortlisted for dynamic simulations. This exhibited a constant RMSD over 20 ns of timescale.

Alicapistat is an orally active selective inhibitor of calpain 1 and 2 whose overactivation has been linked to Alzheimer disease (AD). Three studies were conducted in healthy subjects (18-55 years), 1 in healthy elderly subjects (≥65 years), and 1 in patients with mild to moderate AD. Four studies assessed pharmacokinetics, 1 study in healthy subjects assessed pharmacodynamics (sleep parameters, particularly rapid eye movement [REM], as a measure of central nervous system [CNS] penetration and activity), and all studies assessed safety. Participants received single doses or multiple twice-daily doses of alicapistat for up to 14 days. Maximum alicapistat plasma concentrations were reached in 2 to 5 hours; half-life was 7 to 12 hours postdose. Alicapistat exposure was dose proportional in the alicapistat 50- to 1000-mg dose range. Exposure of the alicapistat R,S diastereomer was approximately 2-fold greater than exposure of the R,R diastereomer in healthy young and elderly subjects and patients with AD. Alicapistat at 400- or 800-mg twice-daily doses had no effect on REM sleep parameters, whereas the active control, donepezil at 10 mg twice daily, affected sleep parameters. Across all trials, the incidence of treatment-emergent adverse events was similar in the placebo and alicapistat groups. There were no clinically significant changes in vital signs and laboratory measurements. The lack of an effect of alicapistat on sleep suggests that concentrations in the CNS were inadequate or that preclinical studies do not predict alicapistat effects in humans., (© 2018, The American College of Clinical Pharmacology.)

Human glutaminyl cyclase (hQC) appeared as a promising new target with its inhibitors attracted much attention for the treatment of Alzheimer's disease (AD) in recent years. But so far, only a few compounds have been reported as hQC inhibitors. To find novel and potent hQC inhibitors, a high-specificity ZBG (zinc-binding groups)-based pharmacophore model comprising customized ZBG feature was first generated using HipHop algorithm in Discovery Studio software for screening out hQC inhibitors from the SPECS database. After purification by docking studies and drug-like ADMET properties filters, four potential hit compounds were retrieved. Subsequently, these hit compounds were subjected to 30-ns molecular dynamic (MD) simulations to explore their binding modes at the active side of hQC. MD simulations demonstrated that these hit compounds formed a chelating interaction with the zinc ion, which was consistent with the finding that the electrostatic interaction was the major driving force for binding to hQC confirmed with MMPBSA energy decomposition. Higher binding affinities of these compounds were also verified by the binding free energy calculations comparing with the references. Thus, these identified compounds might be potential hQC candidates and could be used for further investigation.

Synaptic dysfunction and synapse loss are prominent features in Alzheimer's disease. Members of the Rho-family of guanosine triphosphatases, specifically RhoA, and the synaptic protein Arc are implicated in these pathogenic processes. They share a common regulatory molecule, the E3 ligase Ube3A/E6-AP. Here, we show that Ube3A is reduced in an Alzheimer's disease mouse model, Tg2576 mouse, which overexpresses human APP695 carrying the Swedish mutation, and accumulates Aβ in the brain. Depletion of Ube3A precedes the age-dependent behavioral deficits and loss of dendritic spines in these mice, and results from a decrease in solubility following phosphorylation by c-Abl, after Aβ exposure. Loss of Ube3A triggers the accumulation of Arc and Ephexin-5, driving internalization of GluR1, and activation of RhoA, respectively, culminating in pruning of synapses, which is blocked by restoring Ube3A. Taken together, our results place Ube3A as a critical player in Alzheimer's disease pathogenesis, and as a potential therapeutic target., Competing Interests: The authors declare no competing interests.

Recent evidences suggest the involvement of DYRK1A (dual specificity tyrosine phosphorylation-regulated kinase 1 A) in Alzheimer's disease (AD). Here we showed that DYRK1A undergoes a proteolytic processing in AD patients hippocampus without consequences on its kinase activity. Resulting truncated forms accumulate in astrocytes and exhibit increased affinity towards STAT3ɑ, a regulator of inflammatory process. These findings were confirmed in APP/PS1 mice, an amyloid model of AD, suggesting that this DYRK1A cleavage is a consequence of the amyloid pathology. We identified in vitro the Leucettine L41 as a compound able to prevent DYRK1A proteolysis in both human and mouse protein extracts. We then showed that intraperitoneal injections of L41 in aged APP/PS1 mice inhibit STAT3ɑ phosphorylation and reduce pro-inflammatory cytokines levels (IL1- β, TNF-ɑ and IL-12) associated to an increased microglial recruitment around amyloid plaques and decreased amyloid-β plaque burden. Importantly, L41 treatment improved synaptic plasticity and rescued memory functions in APP/PS1 mice. Collectively, our results suggest that DYRK1A may contribute to AD pathology through its proteolytic process, reducing its kinase specificity. Further evaluation of inhibitors of DYRK1A truncation promises a new therapeutic approach for AD.

Alzheimer's disease (AD) is a genetically complex, progressive and irreversible neurodegenerative disorder of the brain which involves multiple associated etiological targets. The complex pathogenesis of AD gave rise to multi-target-directed ligands (MTDLs) principle to combat this dreaded disease. Within this approach, the design and synthesis of hybrids prevailed greatly because of their capability to simultaneously target the intertwined pathogenesis components of the disease. The hybrids include pharmacophoric hybridization of two or more established chemical scaffolds endowed with the desired pharmacological properties into a single moiety. In AD, the primary foundation of medication therapy and drug design strategies includes the inhibition of cholinesterase (ChE) enzymes. Hence the development of ChE inhibition based hybrids is the central choice of AD medicinal chemistry research. To illustrate the progress of ChE inhibition based hybrids and novel targets, we reviewed the medicinal chemistry and pharmacological properties of the multi-target molecules published since 1998-December 2018. We hope that this article will allow the readers to easily follow the evolution of this prominent medicinal chemistry approach to develop a more efficient inhibitor., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Acetylcholinesterase (AChE) is the key enzyme targeted in Alzheimer's disease (AD) therapy, nevertheless butyrylcholinesterase (BuChE) has been drawing attention due to its role in the disease progression. Thus, we aimed to synthesize novel cholinesterases inhibitors considering structural differences in their peripheral site, exploiting a moiety replacement approach based on the potent and selective hAChE drug donepezil. Hence, two small series of N-benzylpiperidine based compounds have successfully been synthesized as novel potent and selective hBuChE inhibitors. The most promising compounds (9 and 11) were not cytotoxic and their kinetic study accounted for dual binding site mode of interaction, which is in agreement with further docking and molecular dynamics studies. Therefore, this study demonstrates how our strategy enabled the discovery of novel promising and privileged structures. Remarkably, compound 11 proved to be one of the most potent (0.17 nM) and selective (>58,000-fold) hBuChE inhibitor ever reported., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Alzheimer disease (AD) is a harmful neurodegenerative disorder which arises mainly due to awful deposition of amyloid β (Aβ) peptide in the brain of AD patients. Aβ aggregates from the amyloid precursor protein (APP) by the sequential action of β-Secretase (Beta site APP Cleaving Enzyme, BACE1); hence, inhibition of BACE1 is the primary target for the treatment of AD. As per the experimental report, acylguanidine is a synthetic inhibitor of BACE1, it exhibits high binding affinity towards BACE1. In the present computational study, we aimed to understand the molecular binding mechanism of acylguanidine with BACE1 from the structure and conformation, intermolecular interactions, charge density and electrostatic properties, stability and binding free energy of acylguanidine molecule in the active site of BACE1. To investigate this, molecular docking, QM/MM based charge density analysis and MD simulation have been performed on acylguanidine with BACE1. Acylguanidine shows large binding affinity towards BACE1 and it gives strong hydrogen bonding and hydrophobic interactions with the active site amino acid residues of BACE1. In addition, QM/MM based charge density analysis of acylguanidine was carried out to understand its charge density distribution in the active site of BACE1. The conformational flexibility, charge density redistribution and the modification of electrostatic properties of acylguanidine in the active site have been compared to its corresponding gas phase structure. Further, the molecular dynamics simulation on acylguanidine-BACE1 was carried out, which gives the stability of acylguanidine in the active site of BACE1. The MM-GBSA free energy displays the binding affinity of the acylguanidine and further the decomposition energy reveals the validity of intermolecular interactions., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Objectives: Expression of phospholipids and related molecules could provide panels of multiple biomarkers searching for the signature of Alzheimer's disease (AD). The aim of the present study was to quantify ten phospholipids and simultaneously determine phospholipase A 2 (PLA 2 ) activity in blood of mild cognitive impairment (MCI) and AD patients., Methods: Thirty-four AD, 20 MCI and 25 controls were enrolled. The phospholipids where analysed using the AbsoluteIDQ ® p180 Kit. PLA 2 activities were accessed in platelets by a radio-enzymatic assay., Results: The study failed to fix the ten phospholipids as a panel to predict AD; the levels of PCaaC36:6, PCaaC40:6 and C16:1-OH were lower in MCI than in controls (P = 0.041, P = 0.012, P = 0.044 respectively). PCaaC40:2 levels were lower in MCI than in AD (P = 0.041). The converters MCI-AD showed at baseline lower levels of PCaaC40:2 (P = 0.050) and PCaaC40:6 (P = 0.037) than controls. iPLA 2 activity was reduced in AD and MCI than in controls (P < 0.001). We found positive correlation in the control group between PCaaC38:6 and tPLA 2 (r = 0.680; P = 0.001) and sPLA 2 (r = 0.601; P = 0.004); PCaaC40:1 and iPLA 2 (r = 0.503; P = 0.020); PCaaC40:6 and tPLA 2 (r = 0.532; P = 0.013) and sPLA 2 (r = 0.523; P = 0.015)., Conclusions: Lipids metabolites in plasma might indirectly indicate changes in neuronal membrane and this deregulation can outline the transition between healthy and diseased brains.

Due to the exceptional wide range in biochemical activities of natural plant products, Spondias mombim L. are attaining a new height because they present great prospects for drug advancement. This research was designed to analyze the pharmaceutical properties of S. mombim L. ethyl acetate fraction (SMEAF) on key enzymes relevant to erectile and cognitive dysfunction. SMEAF inhibitory activities of the specified enzymes were determined spectrophotometrically. Chemical profile of SMEAF were assessed by HPLC/MS analysis. Thereafter, molecular docking of the studied enzymes with chlorogenic acid, lutein, and zeaxanthin were carried out using PATCHDOCK. SMEAF had remarkable enzyme inhibitory effects against phosphodiesterase-5 (PDE-5), arginase, angiotensin I-converting enzyme (ACE), cholinesterase, monoamine oxidase A (MAO), ecto-5' nucleotidase (E-NTDase), tyrosinase, and stimulated sodium-potassium ATPase (Na+/K+-ATPase) activities. HPLC/MS analysis revealed that phenolics and carotenoids were major components in these fraction notably, chlorogenic acid, lutein, and zeaxanthin. Our results suggested that SMEAF could be explored as phytopharmaceuticals. PRACTICAL APPLICATIONS: Spondias mombim L. are cooked as green vegetable with enormous medicinal value probably due to its polyphenols with potent antioxidant activity. Furthermore, the leaves could also be useful for therapeutic purposes against erectile dysfunction and central nervous system disorders., (© 2019 Wiley Periodicals, Inc.)

Background: Mechanical ventilation is strongly associated with cognitive decline after critical illness. This finding is particularly evident among older individuals who have pre-existing cognitive impairment, most commonly characterized by varying degrees of cerebral amyloid-β accumulation, neuroinflammation, and blood-brain barrier dysfunction. We sought to test the hypothesis that short-term mechanical ventilation contributes to the neuropathology of cognitive impairment by (i) increasing cerebral amyloid-β accumulation in mice with pre-existing Alzheimer's disease pathology, (ii) increasing neurologic and systemic inflammation in wild-type mice and mice with pre-existing Alzheimer's disease pathology, and (iii) increasing hippocampal blood-brain barrier permeability in wild-type mice and mice with pre-existing Alzheimer's disease pathology., Methods: We subjected double transgenic Alzheimer's disease (APP/PSEN1) and wild-type mice to mechanical ventilation for 4 h and compared to non-mechanically ventilated Alzheimer's disease model and wild-type mice. Cerebral soluble/insoluble amyloid-β 1-40 /amyloid-β 1-42 and neurological and systemic markers of inflammation were quantified. Hippocampal blood-brain barrier permeability was quantified using a novel methodology that enabled assessment of small and large molecule permeability across the blood-brain barrier., Results: Mechanical ventilation resulted in (i) a significant increase in cerebral soluble amyloid-β 1-40 (p = 0.007) and (ii) significant increases in neuroinflammatory cytokines in both wild-type and Alzheimer's disease mice which, in most cases, were not reflected in the plasma. There were (i) direct correlations between polymorphonuclear cells in the bronchoalveolar fluid and cerebral soluble amyloid-β 1-40 (p = 0.0033), and several Alzheimer's disease-relevant neuroinflammatory biomarkers including cerebral TNF-α and IL-6; (iii) significant decreases in blood-brain barrier permeability in mechanically ventilated Alzheimer's disease mice and a trend towards increased blood-brain barrier permeability in mechanically ventilated wild-type mice., Conclusions: These results provide the first evidence that short-term mechanical ventilation independently promotes the neuropathology of Alzheimer's disease in subjects with and without pre-existing cerebral Alzheimer's disease pathology. Future studies are needed to further clarify the specific mechanisms by which this occurs and to develop neuroprotective mechanical ventilation strategies that mitigate the risk of cognitive decline after critical illness.

Alzheimer's disease (AD) comprises two major pathological hallmarks: extraneuronal deposition of β-amyloid (Aβ) peptides ("senile plaques") and intraneuronal aggregation of the microtubule-associated protein tau ("neurofibrillary tangles"). Aβ is derived from sequential cleavage of the β-amyloid precursor protein by β- and γ-secretases, while aggregated tau is hyperphosphorylated in AD. Mounting evidence suggests that dysregulated trafficking of these AD-related proteins contributes to AD pathogenesis. Rab proteins are small GTPases that function as master regulators of vesicular transport and membrane trafficking. Multiple Rab GTPases have been implicated in AD-related protein trafficking, and their expression has been observed to be altered in postmortem AD brain. Here we review current implicated roles of Rab GTPase dysregulation in AD pathogenesis. Further elucidation of the pathophysiological role of Rab GTPases will likely reveal novel targets for AD therapeutics.

Alzheimer's disease (AD) is well-known as a severe neurodegeneration disease involving complicated etiologies, and cholinesterase inhibition remain the prevailing mode of clinical intervention in AD management. Although most clinically applied cholinesterase inhibitors (ChEIs) achieve limited clinical outcomes, research on the central cholinergic system is still thriving. Recently, an impressive amount of knowledge regarding novel acetylcholinesterase functions, as well as the close association between the central cholinergic system and other key elements for AD pathogenesis, has accumulated, highlighting that this field still has great potential for future drug development. In contrast to the overwhelmingly disappointing clinical therapeutic effects of various disease-modifying drug candidates, interesting evidence has continued to emerge over the past 20 years from the wealth of preclinical and clinical data on the usage of ChEIs, indicating underestimated clinical benefits due to physician ambivalence, a lack of persistent treatment, and inappropriate medication times or doses. Here we pinpoint several topics fit for future attention, focusing on the updated cholinergic hypothesis, especially the pleiotropic relationships with key pathogenetic signaling pathways and functions in AD, as well as possible novel therapeutic strategies, including novel ChEIs and cholinesterase inhibition-based innovative multifunctional therapeutic candidates. We intend to strengthen the future value of the precise application of cholinergic drugs, especially novel ChEIs, as a cornerstone pharmacological approach to AD treatment, either alone or in combination with other targets, to relieve symptoms and to modify disease progression.

Background: Epidemiologic studies strongly suggest that the pathophysiology of late-onset Alzheimer disease (AD) versus early-onset AD has environmental rather than genetic causes, thus revealing potentially novel therapeutic targets to limit disease progression. Several studies supporting the "pathogen hypothesis" of AD demonstrate a strong association between pathogens and the production of β-amyloid, the pathologic hallmark of AD. Although the mechanism of pathogen-induced neurodegeneration of AD remains unclear, astrocytes, a key player of the CNS innate immune response and producer/metabolizer of β-amyloid, have been implicated. We hypothesized that Chlamydia pneumoniae infection of human astrocytes alters the expression of the amyloid precursor protein (APP)-processing secretases, ADAM10, BACE1, and PSEN1, to promote β-amyloid formation. Utilizing immunofluorescent microscopy, molecular, and biochemical approaches, these studies explore the role of an intracellular respiratory pathogen, Chlamydia pneumoniae, as an environmental trigger for AD pathology. Human astrocytoma cells in vitro were infected with Chlamydia pneumoniae over the course of 6-72 h. The gene and protein expression, as well as the enzymatic activity of non-amyloidogenic (ADAM10), and pro-amyloidogenic (BACE1 and PSEN1) secretases were qualitatively and quantitatively assessed. In addition, the formation of toxic amyloid products as an outcome of pro-amyloidogenic APP processing was evaluated through various modalities., Results: Chlamydia pneumoniae infection of human astrocytoma cells promoted the transcriptional upregulation of numerous genes implicated in host neuroinflammation, lipid homeostasis, microtubule function, and APP processing. Relative to that of uninfected astrocytes, BACE1 and PSEN1 protein levels were enhanced by nearly twofold at 48-72 h post-Chlamydia pneumoniae infection. The processing of APP in Chlamydia pneumoniae-infected astrocytes favors the pro-amyloidogenic pathway, as demonstrated by an increase in enzymatic activity of BACE1, while that of ADAM10 was decreased. Fluorescence intensity of β-amyloid and ELISA-quantified levels of soluble-APP by products revealed temporally similar increases, confirming a BACE1/PSEN1-mediated processing of APP., Conclusions: Our findings suggest that Chlamydia pneumoniae infection of human astrocytes promotes the pro-amyloidogenic pathway of APP processing through the upregulation of expression and activity of β-secretase, upregulated expression of γ-secretase, and decreased activity of α-secretase. These effects of astrocyte infection provide evidence for a direct link between Chlamydia pneumoniae and AD pathology.

Glycogen synthase kinase-3β (GSK-3β) is a key enzyme in hyperphosphorylation of tau proteins and is a promising therapeutic target in Alzheimer's disease (AD). Here, we reported, for the first time, that the stereoisomers of Schisandrin B (Sch B), (+)-1, (-)-1, (+)-2, and (-)-2, were potent GSK-3β inhibitors. They were demonstrated to selectively target GSK-3β in an orthosteric binding mode, with IC 50 values of 340, 290, 80, and 70 nM, respectively. Further study showed that these stereoisomers can significantly increase the expression of p-GSK-3β (Ser9) and decrease the expressions of p-GSK-3β (Tyr216) and p-GSK-3β (Tyr279). Finally, these compounds can alleviate the cell injury induced by Aβ, and the cognitive disorders in AD mice, especially (+)-2 and (-)-2. Collectively, the stereoisomers of Sch B, especially (+)-2 and (-)-2, were found to be potential selective ATP-competitive GSK-3β inhibitors, which further affected their anti-AD effects. These promising findings explained the biological target of Sch B in AD, and bring a new understanding in the stereochemistry and bioactivities of Sch B.

Background: There are currently no approved treatments for the prodromal stage of Alzheimer's disease (AD). Approved symptomatic treatments for mild-to-moderate AD include acetylcholinesterase inhibitors and memantine, but more efficacious treatments are needed. BI 409306 is a potent and selective phosphodiesterase 9 inhibitor assessed for the symptomatic treatment of AD. Efficacy and safety of BI 409306 was analysed in two phase II proof-of-concept clinical trials in cognitive impairment associated with prodromal AD (study 1) and mild AD (study 2)., Methods: Two multicentre, double-blind, parallel-group, randomised controlled phase II studies were conducted (North America/Europe). Following study run-in, eligible subjects were randomised to one of four oral doses of BI 409306 (10-50 mg daily) or placebo (1:1:1:1:2 ratio) for 12 weeks. The primary efficacy endpoint was the change from baseline in Neuropsychological Test Battery (NTB) total z-score after 12 weeks' treatment. Secondary efficacy assessments included change from baseline in Clinical Dementia Rating scale-Sum of Boxes (CDR-SB), Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-Cog11) and Alzheimer's Disease Cooperative Study-Activities of Daily Living scale (ADCS-ADL; mild cognitive impairment [MCI] version for prodromal patients) after 12 weeks' treatment. Safety and tolerability assessments included adverse event reporting and vital sign monitoring. Change from baseline in NTB total z-score (primary endpoint) and CDR-SB were analysed using the restricted maximum likelihood-based mixed-effects model with repeated measurement. An analysis of covariance model was used to assess other secondary endpoints., Results: Four hundred fifty-seven patients were randomised (study 1 for prodromal AD, N = 128; study 2 for mild AD, N = 329); 427 (93.4%) completed. A prespecified pooled analysis of the primary endpoint revealed no significant changes in NTB total composite z-score at week 12 in the BI 409306 treatment groups compared with placebo, with similar findings observed in the individual studies. The analysis of all secondary endpoints, including pooled analysis of CDR-SB and ADAS-Cog11, ADCS-MCI-ADL (study 1), ADCS-ADL (study 2), also gave no indication of a treatment benefit for BI 409306, compared with placebo. BI 409306 was well tolerated., Conclusions: Overall, the data do not demonstrate efficacy of BI 409306 in improving cognition in patients with prodromal and mild AD. BI 409306 is well tolerated., Trial Registration: ClinicalTrials.gov, NCT02240693 and NCT02337907 . Registered 15 September 2014 and 09 January 2015, respectively.

Nicotinamide adenine dinucleotide (reduced form: NADH) serves as a vital redox-energy currency for reduction-oxidation homeostasis and fulfilling energetic demands. While NADH exists as free and bound forms, only free NADH is utilized for complex I to power oxidative phosphorylation, especially important in neurons. Here, we studied how much free NADH remains available for energy production in mitochondria of old living neurons. We hypothesize that free NADH in neurons from old mice is lower than the levels in young mice and even lower in neurons from the 3xTg-AD Alzheimer's disease (AD) mouse model. To assess free NADH, we used lifetime imaging of NADH autofluorescence with 2-photon excitation to be able to resolve the pool of NADH in mitochondria, cytoplasm, and nuclei. Primary neurons from old mice were characterized by a lower free/bound NADH ratio than young neurons from both non-transgenic (NTg) and more so in 3xTg-AD mice. Mitochondrial compartments maintained 26 to 41% more reducing NADH redox state than cytoplasm for each age, genotype, and sex. Aging diminished the mitochondrial free NADH concentration in NTg neurons by 43% and in 3xTg-AD by 50%. The lower free NADH with age suggests a decline in capacity to regenerate free NADH for energetic supply to power oxidative phosphorylation which further worsens in AD. Applying this non-invasive approach, we showed the most explicit measures yet of bioenergetic deficits in free NADH with aging at the subcellular level in live neurons from in-bred mice and an AD model.

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases with a multifactorial nature. β-Secretase (BACE1) and acetylcholinesterase (AChE), which are required for the production of neurotoxic β-amyloid (Aβ) and the promotion of Aβ fibril formation, respectively, are considered as prime therapeutic targets for AD. In our efforts towards the development of potent multi-target, directed agents for AD treatment, major phlorotannins such as eckol, dieckol, and 8,8'-bieckol from Ecklonia cava ( E. cava ) were evaluated. Based on the in vitro study, all tested compounds showed potent inhibitory effects on BACE1 and AChE. In particular, 8,8'-bieckol demonstrated the best inhibitory effect against BACE1 and AChE, with IC 50 values of 1.62 ± 0.14 and 4.59 ± 0.32 µM, respectively. Overall, kinetic studies demonstrated that all the tested compounds acted as dual BACE1 and AChE inhibitors in a non-competitive or competitive fashion, respectively. In silico docking analysis exhibited that the lowest binding energies of all compounds were negative, and specifically different residues of each target enzyme interacted with hydroxyl groups of phlorotannins. The present study suggested that major phlorotannins derived from E. cava possess significant potential as drug candidates for therapeutic agents against AD.

Alzheimer's disease (AD) is a neurodegenerative disorder with multifactorial pathogenesis. Monoamine oxidase (MAO) and acetylcholinesterase enzymes (AChE) are potential targets for the treatment of AD. A total of 15 new propargyl containing 4,6-diphenylpyrimidine derivatives were synthesized and screened for the MAO and AChE inhibition activities along with ROS production inhibition and metal-chelation potential. All the synthesized compounds were found to be selective and potent inhibitors of MAO-A and AChE enzymes at nanomolar concentrations. VB1 was found to be the most potent MAO-A and BuChE inhibitor with IC 50 values of 18.34 ± 0.38 nM and 0.666 ± 0.03 μM, respectively. It also showed potent AChE inhibition with an IC 50 value of 30.46 ± 0.23 nM. Compound VB8 was found to be the most potent AChE inhibitor with an IC 50 value of 9.54 ± 0.07 nM and displayed an IC 50 value of 1010 ± 70.42 nM against the MAO-A isoform. In the cytotoxic studies, these compounds were found to be nontoxic to the human neuroblastoma SH-SY5Y cells even at 25 μM concentration. All the compounds were found to be reversible inhibitors of MAO-A and AChE enzymes. In addition, these compounds also showed good neuroprotective properties against 6-OHDA- and H 2 O 2 -induced neurotoxicity in SH-SY5Y cells. All the compounds accommodate nicely to the hydrophobic cavity of MAO-A and AChE enzymes. In the molecular dynamics simulation studies, both VB1 and VB8 were found to be stable in the respective cavities for 30 ns. Thus, 4,6-diphenylpyrimidine derivatives can act as promising leads in the development of dual-acting inhibitors targeting MAO-A and AChE enzymes for the treatment of Alzheimer's disease.

Multifunctional agents aiming at cholinesterases (ChEs) and monoamine oxidases (MAOs) are promising therapy for Alzheimer's disease (AD). Herein, a series of novel propargylamine-modified pyrimidinylthiourea derivatives (1-4) were designed and synthesized as dual inhibitors of ChEs and MAOs with other functions against AD. Most of these derivatives inhibited ChEs and MAOs with IC 50 values in the micro- or nanomolar ranges. Compound 1c displayed the dual functional profile of targeting the AChE (IC 50 = 0.032 ± 0.007 μM) and MAO-B (IC 50 = 2.117 ± 0.061 μM), along with the improved blood-brain barrier (BBB) permeability, antioxidant ability, and good copper chelating property in vitro. Animal studies showed that compound 1c·HCl could inhibit the cerebral AChE/MAO-B activities and alleviate scopolamine-induced cognitive impairment in mice. Combined with good oral bioavailability ( F = 45.55%), these findings demonstrated that compound 1c may be a potent brain permeable multifunctional candidate for the treatment of AD.

Alzheimer's disease (AD) and diabetes are clinically positively correlated. However, the connection between them is not clarified. Here, using Drosophila as a model system, we show that reducing insulin signaling can effectively suppress the toxicity from Aβ (Amyloid beta 42) expression. On the other hand, Aβ accumulation led to the elevation of fly insulin-like peptides (ILPs) and activation of insulin signaling in the brain. Mechanistically, these observations are attributed to a reciprocal competition between Drosophila insulin-like peptides and Aβ for the activity of insulin-degrading enzyme (IDE). Intriguingly, peripheral insulin signaling is decreased despite its heightened activity in the brain. While many upstream factors may modify Aβ toxicity, our results suggest that insulin signaling is the main downstream executor of Aβ damage, and thus may serve as a promising target for Alzheimer's treatment in non-diabetes patients. This study explains why more Alzheimer's cases are found in diabetes patients., Competing Interests: The authors declare no competing interests.

Cysteinyl leukotrienes (cysLTs) are member of eicosanoid inflammatory lipid mediators family produced by oxidation of arachidonic acid by action of the enzyme 5-lipoxygenase (5-LOX). 5-LOX is activated by enzyme 5-Lipoxygenase-activating protein (FLAP), which further lead to production of cysLTs i.e. leukotriene C4 (LTC4), leukotriene D4 (LTD4) and leukotriene E4 (LTE4). CysLTs then produce their potent inflammatory actions by activating CysLT1 and CysLT2 receptors. Inhibitors of cysLTs are indicated in asthma, allergic rhinitis and other inflammatory disorders. Earlier studies have associated cysLTs and their receptors in several neurodegenerative disorders diseases like, multiple sclerosis, Parkinson's disease, Huntington's disease, epilepsy and Alzheimer's disease (AD). These inflammatory lipid mediators have previously shown effects on various aggravating factors of AD. However, not much data has been elucidated to test their role against AD clinically. Herein, through this review, we have provided the current and emerging information on the role of cysLTs and their receptors in various neurological complications responsible for the development of AD. In addition, literature evidences for the effect of cysLT inhibitors on distinct aspects of abnormalities in AD has also been reviewed. Promising advancement in understanding on the role of cysLTs on the various neuromodulatory processes and mechanisms may contribute to the development of newer and safer therapy for the treatment of AD in future., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Aim: The aim of this study was to evaluate acetylcholinesterase (AChE) and pseudocholinesterase (PChE) in whole saliva in patients with Alzheimer's disease (AD) and in healthy subjects. Saliva has a high potential for keeping track of general health and diseases. AD is a type of dementia with reduction in brain cholinergic markers that causes memory, thinking, and behavior problems. Up to 90% decrease in AChE activity has been observed in AD., Methods and Results: Thirty healthy subjects and 30 patients with AD participated in this study. Saliva samples were collected from 8 to 10 am. AChE and PChE of saliva were assessed by the Ellman method. Statistical comparison was performed using SPSS 16 for t-test. The activity of AChE and PChE significantly increased in the group with AD compared to the healthy subjects. Sex had no effect on the activities of these enzymes. No correlation existed between the duration of illness and enzymatic activity. The enzyme levels reduced with age., Conclusion: AChE and PChE levels were increased in saliva samples of patients with AD. Therefore, saliva has the potential for being used for the purpose of biomarker evaluation to replace cerebrospinal fluid in patients with AD., (© 2018 Special Care Dentistry Association and Wiley Periodicals, Inc.)

Alzheimer's Disease (AD), affecting a large population worldwide is characterized by the loss of memory and learning ability in the old population. The enzyme Acetylcholinesterase Enzyme (AChE) is the key enzyme in the hydrolysis of the neurotransmitter acetylcholine and is also the target of most of the clinically used drugs for the treatment of AD but these drugs provide only symptomatic treatment and have the limitation of loss of therapeutic efficacy with time. The development of different strategies targeting the AChE enzyme along with other targets like Butyl Cholinesterase (BChE), amyloid-β (Aβ), β-secretase-1 (BACE), metals antioxidant properties and free radical scavenging capacity has been focused in recent years. Literature search was conducted for the molecules and their rational design which have shown inhibition for AChE and the other abovementioned targets. Several hybrid molecules incorporating the main sub-structures derived from diverse chemotypes like acridine, quinoline, carbamates, and other heterocyclic analogs have shown desired pharmacological activity with a good profile in a single molecule. It is followed by optimization of the activity through structural modifications guided by structure-activity relationship studies. It has led to the discovery of novel molecules 17b, 20, and 23 with desired AChE inhibition along with desirable activity against other abovementioned targets for further pre-clinical studies., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Currently there is no cure or effective disease-modifying therapy for Alzheimer's disease (AD), the most common form of dementia that is becoming a global threat to public health. It is important to develop novel therapeutic strategies targeting AD pathophysiology particularly synaptic failure and cognitive impairments. Recent studies revealed several molecular signaling pathways potentially linked to brain pathology and synaptic failure in AD, including AMP-activated protein kinase (AMPK), a master kinase that plays a central role in the maintenance of cellular energy homeostasis. Particularly, hyperactive AMPK via phosphorylation has been linked to AD-associated synaptic plasticity impairments, indicating suppression of AMPK activity might be beneficial for cognitive deficiency in AD. In this review, we will discuss how targeting dysregulation of AMPK signaling could be a feasible therapeutic approach for AD.

Genetics strongly implicate the amyloid β-peptide (Aβ) in the pathogenesis of Alzheimer's disease. Dominant missense mutation in the presenilins and the amyloid precursor protein (APP) cause early-onset familial Alzheimer's disease (FAD). As presenilin is the catalytic component of the γ-secretase protease complex that produces Aβ from APP, mutation of the enzyme or substrate that produce Aβ leads to FAD. However, the mechanism by which presenilin mutations cause FAD has been controversial, with gain of function and loss of function offered as binary choices. This overview will instead present the case that presenilins are dysfunctional in FAD. γ-Secretase is a multi-functional enzyme that proteolyzes the APP transmembrane domain in a complex and processive manner. Reduction in a specific function-the carboxypeptidase trimming of initially formed long Aβ peptides containing most of the transmembrane domain to shorter secreted forms-is an emerging common feature of FAD-mutant γ-secretase complexes.

Alzheimer's, a degenerative cause of the brain cells, is called as a progressive neurodegenerative disease and appears to have a heterogeneous etiology with main emphasis on amyloid-cascade and hyperphosphorylated tau-cascade hypotheses, that are directly linked with macromolecules called enzymes such as β- & γ-secretases, colinesterases, transglutaminases, and glycogen synthase kinase (GSK-3), cyclin-dependent kinase (cdk-5), microtubule affinity-regulating kinase (MARK). The catalytic activity of the above enzymes is the result of cognitive deficits, memory impairment and synaptic dysfunction and loss, and ultimately neuronal death. However, some other enzymes also lead to these dysfunctional events when reduced to their normal activities and levels in the brain, such as α- secretase, protein kinase C, phosphatases etc; metabolized to neurotransmitters, enzymes like monoamine oxidase (MAO), catechol-O-methyltransferase (COMT) etc. or these abnormalities can occur when enzymes act by other mechanisms such as phosphodiesterase reduces brain nucleotides (cGMP and cAMP) levels, phospholipase A2: PLA2 is associated with reactive oxygen species (ROS) production etc. On therapeutic fronts, several significant clinical trials are underway by targeting different enzymes for development of new therapeutics to treat Alzheimer's, such as inhibitors for β-secretase, GSK-3, MAO, phosphodiesterase, PLA2, cholinesterases etc, modulators of α- & γ-secretase activities and activators for protein kinase C, sirtuins etc. The last decades have perceived an increasing focus on findings and search for new putative and novel enzymatic targets for Alzheimer's. Here, we review the functions, pathological roles, and worth of almost all the Alzheimer's associated enzymes that address to therapeutic strategies and preventive approaches for treatment of Alzheimer's., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Elucidating the relationship between neuronal metabolism and the integrity of the cholinergic system is prerequisite for a profound understanding of cholinergic dysfunction in Alzheimer's disease. The cholinergic system can be investigated specifically using positron emission tomography (PET) with [ 11 C]N-methyl-4-piperidyl-acetate (MP4A), while neuronal metabolism is often assessed with 2-deoxy-2-[ 18 F]fluoro-d-glucose-(FDG) PET. We hypothesised a close correlation between MP4A-perfusion and FDG-uptake, permitting inferences about metabolism from MP4A-perfusion, and investigated the patterns of neuronal hypometabolism and cholinergic impairment in non-demented AD patients. MP4A-PET was performed in 18 cognitively normal adults and 19 patients with mild cognitive impairment (MCI) and positive AD biomarkers. In nine patients with additional FDG-PET, the sum images of every combination of consecutive early MP4A-frames were correlated with FDG-scans to determine the optimal time window for assessing MP4A-perfusion. Acetylcholinesterase (AChE) activity was estimated using a 3-compartmental model. Group comparisons of MP4A-perfusion and AChE-activity were performed using the entire sample. The highest correlation between MP4A-perfusion and FDG-uptake across the cerebral cortex was observed 60-450 s after injection (r = 0.867). The patterns of hypometabolism (FDG-PET) and hypoperfusion (MP4A-PET) in MCI covered areas known to be hypometabolic early in AD, while AChE activity was mainly reduced in the lateral temporal cortex and the occipital lobe, sparing posterior midline structures. Data indicate that patterns of cholinergic impairment and neuronal hypometabolism differ significantly at the stage of MCI in AD, implying distinct underlying pathologies, and suggesting potential predictors of the response to cholinergic pharmacotherapy., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)

Certain proteases are involved in Alzheimer's disease (AD) and their erroneous control may contribute to the pathology onset and progression. In this study we evaluated the cerebral expression of eight proteases, involved in both AβPP processing and extracellular matrix remodeling. Among these proteases, ADAM10, ADAMTS1, Cathepsin D, and Meprin β show a significantly higher mRNAs expression in sporadic AD subjects versus controls, while ADAMTS1, Cathepsin D, and Meprin β show an increment also at the protein level. These data indicate that transcriptional events affecting brain proteases are activated in AD patients, suggesting a link between proteolysis and AD.

Background: Alzheimer's disease (AD) is the most common cause of dementia in elderly populations. Changes in the expression of the Amyloid Precursor Protein (APP)-cleaving enzymes directly affect the formation of Amyloid Beta (Aβ) plaques, a neuropathological hallmark of AD., Objective: We used peripheral blood from AD patients to investigate the expression of genes related to APP-processing [(β-site APP-cleaving enzyme 1 (BACE1), presenilin1 (PSEN1), and a disintegrin and metalloproteinase family 10 (ADAM10) and 17 (ADAM17)] and the epigenetic genes sirtuin (SIRT)1-3, which regulate Aβ production., Method: Real-time polymerase chain reactions were performed to determine the specific mRNA levels in plasma. The mRNA levels in AD patients were compared to those in healthy persons and assessed in relation to the subjects' cognitive performance., Results: BACE1 mRNA level in AD subjects was significantly higher than those of healthy controls, whereas ADAM10 level was significantly lower in the AD subjects. The SIRT1 level was significantly decreased, while that of SIRT2 was increased in AD subjects and elderly controls compared to levels in healthy young control. In addition, correlations were found between the expression levels of BACE1, ADAM10 and SIRT1 and cognitive performance scores. Total Aβ (Aβ40+Aβ42) levels and the Aβ40/Aβ42 ratio were significantly increased in the AD subjects, whereas decrease in plasma Aβ42 was found in AD subjects. There was a negative correlation between Aβ40 or total Aβ and Thai Mental State Examination (TMSE) while there was no correlation between Aβ40/Aβ42 ratio or Aβ42 and TMSE., Conclusion: The present findings provide evidence and support for the potential roles of these enzymes that drive Aβ synthesis and for epigenetic regulation in AD progression and development, which can possibly be considered peripheral markers of AD., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

In the current research work, a series of new N-(alkyl/aralkyl)-N-(2,3-dihydro-1,4-benzodioxan-6-yl)-4-chlorobenzenesulfonamides has been synthesized by reacting 1,4-benzozzdioxan-6-amine (1) with 4-chlorobenzenesulfonyl chloride (2) to yield N-(2,3-dihydro-1,4-benzodioxan-6-yl)-4-chlorobenzenesulfonamide (3) which was further reacted with different alkyl/aralkyl halides (4a-n) to afford the target compounds (5a-n). Structures of the synthesized compounds were confirmed by IR, 1H-NMR, EI-MS spectral techniques and CHN analysis data. The results of enzyme inhibition showed that the molecules, N-2-phenethyl-N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-chlorobenzenesulfonamide (5j) and N-(1-butyl)-N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-chlorobenzenesulfonamide (5d), exhibited moderate inhibitory potential against acetylcholinesterase with IC50 values 26.25±0.11 μM and 58.13±0.15 μM respectively, whereas, compounds N-benzyl-N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-chlorobenzenesulfonamide (5i) and N-(pentane-2-yl)-N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-chlorobenzenesulfonamide (5f) showed moderate inhibition against α-glucosidase enzyme as evident from IC50 values 74.52±0.07 and 83.52±0.08 μM respectively, relative to standards Eserine having IC50 value of 0.04±0.0001 μM for cholinesterases and Acarbose having IC50 value 38.25±0.12 μM for α-glucosidase, respectively.

Tacrine is a potent inhibitor of cholinesterases (acetylcholinesterase and butyrylcholinesterase) that shows limiting clinical application by liver toxicity. In spite of this, analogues of tacrine are considered as a model inhibitor of cholinesterases in the therapy of Alzheimer's disease. The interest in these compounds is mainly related to a high variety of their structure and biological properties. In the present review, we have described the role of cholinergic transmission and treatment strategies in Alzheimer's disease as well as the synthesis and biological activity of several recently developed classes of multifunctional tacrine analogues and hybrids, which consist of a new paradigm to treat Alzheimer's disease. We have also reported potential of these analogues in the treatment of Alzheimer's diseases in various experimental systems., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Elevated levels of cyclooxygenase-2 (COX-2) and prostaglandins (PGs) are involved in the pathogenesis of Alzheimer's disease (AD), which is characterized by the accumulation of β-amyloid protein (Aβ) and tau hyperphosphorylation. However, the gaps in our knowledge of the roles of COX-2 and PGs in AD have not been filled. Here, we summarized the literature showing that COX-2 dysregulation obviously influences abnormal cleavage of β-amyloid precursor protein, aggregation and deposition of Aβ in β-amyloid plaques and the inclusion of phosphorylated tau in neurofibrillary tangles. Neuroinflammation, oxidative stress, synaptic plasticity, neurotoxicity, autophagy, and apoptosis have been assessed to elucidate the mechanisms of COX-2 regulation of AD. Notably, an imbalance of these factors ultimately produces cognitive decline. The current review substantiates our understanding of the mechanisms of COX-2-induced AD and establishes foundations for the design of feasible therapeutic strategies to treat AD.-Guan, P.-P., Wang, P. Integrated communications between cyclooxygenase-2 and Alzheimer's disease.

Alzheimer's disease (AD) is the most common cause of dementia, characterized by loss of selective neuronal and normal brain functions. Every year, ten million new cases are diagnosed worldwide. AD is a complex disease associated with all kind of different pathways, making their simultaneous modulation necessary. Nowadays anti-AD treatments are focused on enzymatic inhibitors. The study of the amphibians' skin had acquired great importance in the fields of biology and human health and represents an attractive and novel source for natural compounds with high potential in the development of new drugs. The present work exhibits the power of amphibian skins as a source of bioactive compounds. Herein we report the activity of extracts of two species from Hylidae family (H. cordobae and P. minuta) as reversible inhibitors of acetylcholinesterase and butyrylcholinesterase enzymes. Furthermore, the extracts inhibit MAO-B enzyme and showed antioxidant activities, acting on four important pathways of AD., (© 2019 Wiley-VHCA AG, Zurich, Switzerland.)

Background: Deposition of the amyloid β protein (Aβ) into neuritic plaques is the neuropathological hallmark of Alzheimer's Disease (AD). Aβ is generated through the cleavage of the Amyloid Precursor Protein (APP) by β-secretase and γ-secretase. Currently, the evaluation of APP cleavage by β-secretase in experimental settings has largely depended on models that do not replicate the physiological conditions of this process., Objective: To establish a novel live cell-based β-secretase enzymatic assay utilizing a novel chimeric protein that incorporates the natural sequence of APP and more closely replicates its cleavage by β-secretase under physiological conditions., Methods: We have developed a chimeric protein construct, ASGβ, incorporating the β-site cleavage sequence of APP targeted by β-secretase and its intracellular trafficking signal into a Phosphatase-eGFP secreted reporter system. Upon cleavage by β-secretase, ASGβ releases a phosphatase-containing portion that can be measured in the culture medium, and an intracellular fraction that can be detected through Western Blot. Subsequently, we have generated a cell line stably expressing ASGβ that can be utilized to assay β-secretase in real time., Results: ASGβ is specifically targeted by β-secretase, being cleaved exclusively at the site responsible for the generation of Aβ. Dosage response to β-secretase inhibitors shows that β-secretase activity can be positively correlated to phosphatase activity in culture media., Conclusion: Our findings suggest this system could be a high-throughput tool to screen compounds that aim to modulate β-secretase activity and Aβ production under physiological conditions, as well as evaluating factors that regulate this cleavage., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Background: Amyloid-β (Aβ) accumulation plays a critical role in the pathogenesis of Alzheimer's disease (AD) lesions. Deficiency of Serotonin signaling recently has been linked to the increased Aβ level in transgenic mice and humans. In addition, tryptophan hydroxylase-2 (Tph2), a second tryptophan hydroxylase isoform, controls brain serotonin synthesis. However, it remains to be determined that whether Tph2 deficient APP/PS1mice affect the formation of Aβ plaques in vivo., Methods: Both quantitative and qualitative immunochemistry methods, as well as Congo red staining were used to evaluate the Aβ load and astrogliosis in these animals., Results: we studied alterations of cortex and hippocampus in astrocytes and senile plaques by Tph2 conditional knockout (Tph2 CKO) AD mice from 6-10 months of age. Using Congo red staining and immunostained with Aβ antibody, we showed that plaques load or plaques numbers significantly increased in Tph2 CKO experimental groups at 8 to 10 months old, compared to wild type (WT) group, respectively. Using GFAP+ astrocytes immunofluorescence method, we found that the density of GFAP+ astrocytes markedly enhanced in Tph2 CKO at 10 months. We showed Aβ plaques co-localized autophagic markers LC3 and p62. Nevertheless, we did not observe any co-localization between GFAP+ astrocytes and autophagic markers, but detected the co-localization between βIII-tubulin+ neurons and autophagic markers., Conclusion: Overall, our work provides the preliminary evidence in vivo that Tph2 plays a role in amyloid plaques generation., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Background: Astrocytes produce and store the energy reserve glycogen. However, abnormal large glycogen units accumulate if the production or degradation of glycogen is disturbed, a finding often seen in patients with Alzheimer's disease (AD). We have shown increased activity of glycogen degrading α-amylase in AD patients and α-amylase positive glial cells adjacent to AD characteristic amyloid-β (Aβ) plaques., Objectives: Investigate the role of α-amylase in astrocytic glycogenolysis in presence of Aβ., Methods: Presence of α-amylase and large glycogen units in postmortem entorhinal cortex from AD patients and non-demented controls were analyzed by immunohistological stainings. Impact of different Aβ42 aggregation forms on enzymatic activity (α-amylase, pyruvate kinase, and lactate dehydrogenase), lactate secretion, and accumulation of large glycogen units in cultured astrocytes were analyzed by activity assays, ELISA, and immunocytochemistry, respectively., Results: AD patients showed increased number of α-amylase positive glial cells. The glial cells co-expressed the astrocytic marker glial fibrillary acidic protein, displayed hypertrophic features, and increased amount of large glycogen units. We further found increased load of large glycogen units, α-amylase immunoreactivity and α-amylase activity in cultured astrocytes stimulated with fibril Aβ42, with increased pyruvate kinase activity, but unaltered lactate release as downstream events. The fibril Aβ42-induced α-amylase activity was attenuated by β-adrenergic receptor antagonist propranolol., Discussion: We hypothesize that astrocytes respond to fibril Aβ42 in Aβ plaques by increasing their α-amylase production to either liberate energy or regulate functions needed in reactive processes. These findings indicate α-amylase as an important actor involved in AD associated neuroinflammation.

BACKGROUND Acyl-coenzymeA: cholesterol acyltransferase (ACAT) 1, a key enzyme converting excess free cholesterol to cholesterol esters, has been demonstrated to be associated with the pathogenesis of Alzheimer disease (AD). However, the mechanism underlying the protective role of ACAT1 blockage in AD progression remains elusive. MATERIAL AND METHODS Human neuroblastoma SH-SY5Y cells were treated for 24 h with increasing concentrations of aggregated Aβ₂₅₋₃₅ (5, 15, 25, and 45 μmol) with or without the ACAT1 siRNA pretreatment. Cell viability analysis was measured by CCK-8 assay. The genome-wide correlation between ACAT1 and all other probe sets was measured by the Pearson correlation coefficient (r). Western blotting was used to detect the ACAT1 protein expression in the hippocampus of APP/PSN transgenic AD mice. The mRNA level for each target was analyzed by qPCR. Western blotting was used to detect the ACAT1, cyclo-oxygenase-2 (Cox2), Calcium voltage-gated channel subunits (CACNAs), and ERK/PKC proteins in SH-SY5Y cells with or without the ACAT1 siRNA pretreatment in the presence of Aβ₂₅₋₃₅. RESULTS The expression of ACAT1 was significantly increased in the hippocampus of APP/PSN mice, and also showed an increasing trend when SH-SY5Y cells were exposed to Aβ₂₅₋₃₅. Silencing ACAT1 significantly attenuated Aβ-induced cytotoxicity and cell apoptosis in SH-SY5Y cells. The genome-wide correlation analysis showed that Ptgs2 had the most significant correlation with Acat1 in the hippocampus of BXD RI mice. We further determined the regulatory effect of ACAT1 on COX2 expression by silencing or over-expressing ACAT1 in SH-SY5Y cells and found that silencing ACAT1 played a protective role in AD progression by regulating CACNAs and PKC/ERK signaling cascades. CONCLUSIONS Silencing ACAT1 attenuates Aβ₂₅₋₃₅-induced cytotoxicity and cell apoptosis in SH-SY5Y cells, which may due to the synergistic effect of ACAT1 and COX2 through PKC/ERK pathways.

A new series of multifunctional amides has been synthesized having moderate enzyme inhibitory potentials and mild cytotoxicity. 2-Furyl(1-piperazinyl)methanone (1) was coupled with 3,5-dichloro-2-hydroxybenzenesulfonyl chloride (2) to form {4-[(3,5-dichloro-2-hydroxyphenyl)sulfonyl]-1-piperazinyl}(2-furyl)methanone (3). Different elecrophiles were synthesized by the reaction of various un/substituted anilines (4a-o) with 2-bromoacetylbromide (5), 2‑bromo‑N-(un/substituted-phenyl)acetamides (6a-o). Further, equimolar ratios of 3 and 6a-o were allowed to react in the presence of K 2 CO 3 in acetonitrile to form desired multifunctional amides (7a-o). The structural confirmation of all the synthesized compounds was carried out by their EI-MS, IR, 1 H NMR and 13 C NMR spectral data. Enzyme inhibition activity was performed against acetyl and butyrylcholinestrase enzymes, whereby 7e showed very good activity having IC 50 value of 5.54 ± 0.03 and 9.15 ± 0.01 μM, respectively, relative to eserine, a reference standard. Hemolytic activity of the molecules was checked to asertain their cytotoxicity towards red blood cell membrance and it was observed that most of the compounds were not toxic up to certain range. Moreover, chemoinformatic protepties and docking simulation results also showed the significance of 7e as compared to other compounds. Based on in vitro and in silico analysis 7e could be used as a template for the development of new drugs against Alzheimer's disease., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

A series of new coumarin-dithiocarbamate hybrids were designed and synthesized as multitarget agents for the treatment of Alzheimer's disease. Most of them showed potent and clearly selective inhibition towards AChE and MAO-B. Among these compounds, compound 8f demonstrated the most potent inhibition to AChE with IC 50 values of 0.0068 μM and 0.0089 μM for eeAChE and hAChE, respectively. Compound 8g was identified as the most potent inhibitor to hMAO-B, and it is also a good and balanced inhibitor to both hAChE and hMAO-B (0.114 µM for hAChE; 0.101 µM for hMAO-B). Kinetic and molecular modeling studies revealed that 8g was a dual binding site inhibitor for AChE and a competitive inhibitor for MAO-B. Further studies indicated that 8g could penetrate the BBB and exhibit no toxicity on SH-SY5Y neuroblastoma cells. More importantly, 8g did not display any acute toxicity in mice at doses up to 2500 mg/kg and could reverse the cognitive dysfunction of scopolamine-induced AD mice. Overall, these results highlighted 8g as a potential multitarget agent for AD treatment and offered a starting point for design of new multitarget AChE/MAO-B inhibitors based on dithiocarbamate scaffold., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Excessive production of amyloid β (Aβ) induced by familial mutations in amyloid precursor protein (APP) and presenilin 1 (PS1) results in neuronal oxidative insults, mitochondrial dysfunction, and apoptosis, which play an essential role in the pathological development of Alzheimer's disease (AD). Aloperine, a quinolizidine alkaloid derived from the leaves of the Sophora plant, has displayed multiple pharmacological functions in several chronic diseases. In the current study, we investigated the neuro-protective effects of aloperine against cytotoxicity in mouse Neuro2a (N2a) cells transfected with Swedish amyloid precursor protein (Swe-APP) mutant and presenilin 1 exon 9 deletion mutant (N2a/Swe.D9). We found that aloperine ameliorated oxidative stress patterns in N2a/Swe.D9 cells by reducing the production of reactive oxygen species (ROS) and 4-hydroxy-2-nonenal (4-HNE). Additionally, aloperine treatment led to elevated generation of ATP and increased mitochondrial membrane potential (MMP) in N2a/Swe.D9 cells. Importantly, we found that aloperine treatment reduced the vulnerability of N2a/Swe.D9 cells to H 2 O 2 . Aloperine also inhibited apoptosis of N2a/Swe.D9 cells via a mitochondria-dependent pathway. These findings suggest that aloperine may have pharmacological potential for the treatment of AD., (Copyright © 2018. Published by Elsevier Masson SAS.)

Phosphodiesterase-9 (PDE9) is a promising target for treatment of Alzheimer's disease (AD). To discover multifunctional anti-AD agents with capability of PDE9 inhibition and antioxidant activity, a series of novel pyrazolopyrimidinone derivatives, coupling with the pharmacophore of antioxidants such as ferulic and lipolic acids have been designed with the assistance of molecular docking and dynamics simulations. Twelve out of 14 synthesised compounds inhibited PDE9A with IC 50 below 200 nM, and showed good antioxidant capacities in the ORAC assay. Compound 1h, the most promising multifunctional anti-AD agent, had IC 50 of 56 nM against PDE9A and good antioxidant ability (ORAC (trolox) = 3.3). The selectivity of 1h over other PDEs was acceptable. In addition, 1h showed no cytotoxicity to human neuroblastoma SH-SY5Y cells. The analysis on structure-activity relationship (SAR) and binding modes of the compounds may provide insight into further modification.

Inhibition of glycogen synthase kinase 3β (GSK-3β) is considered to be the central therapeutic approach against Alzheimer's disease (AD). In the present study, boiled water extracts of the Kangen-karyu (KK) herbal mixture and its constituents were screened for GSK-3β inhibitory activity. KK is used in traditional Kampo and Chinese medicines for improving cognitive function. The GSK-3β inhibition potential was evaluated by using the Kinase-Glo luminescent kinase assay platform. Furthermore, enzyme kinetics and in silico modeling were performed by using AutoDockTools to demonstrate the mechanism of enzyme inhibition. KK extract significantly inhibited GSK-3β in a concentration-dependent manner (IC 50 : 17.05 ± 1.14 μg/mL) when compared with the reference drug luteolin (IC 50 : 2.18 ± 0.13 μM). Among the six components of KK, extracts of Cyperi Rhizoma and Salviae Miltiorrhizae Radix significantly inhibited GSK-3β with IC 50 values of 20.68 ± 2.50 and 7.77 ± 1.38 μg/mL, respectively. Among the constituents of the roots of S. miltiorrhiza water extract, rosmarinic acid, magnesium lithospermate B, salvianolic acid A, salvianolic acid B, and salvianolic acid C inhibited GSK-3β with IC 50 values ranging from 6.97 to 135.5 μM. Salvianolic acid B was found to be an ATP-competitive inhibitor of GSK-3β and showed the lowest IC 50 value (6.97 ± 0.96 µM). In silico modeling suggested a mechanism of action by which the hydrophobic, π⁻cation, and hydrophilic interactions of salvianolic acid B at ATP and substrate sites are critical for the observed GSK-3β inhibition. Therefore, one of the mechanisms of action of KK against AD may be the inhibition of GSK-3β and one of the active components of KK is the root of S. miltiorrhiza and its constituents: rosmarinic acid, magnesium lithospermate B, and salvianolic acids A, B, and C. Our results demonstrate the pharmacological basis for the use of KK against AD.

Insulin-degrading enzyme (IDE) is a zinc metalloprotease that selectively degrades biologically important substrates associated with type 2 diabetes and Alzheimer's disease (AD). As such, IDE is an attractive target for therapeutic innovations. A major requirement is an understanding of how other molecules present in cells regulate the activity of the enzyme toward insulin, IDE's most important physiologically relevant substrate. Previous kinetic studies of the IDE-dependent degradation of insulin in the presence of potential regulators have used iodinated insulin, a chemical modification that has been shown to alter the biological and biochemical properties of insulin. Here, we present a novel kinetic assay that takes advantage of the loss of helical circular dichroic signals of insulin with IDE-dependent degradation. As proof of concept, the resulting Michaelis-Menten kinetic constants accurately predict the known regulation of IDE by adenosine triphosphate (ATP). Intriguingly, we found that when Mg 2+ is present with ATP, the regulation is abolished. The implication of this result for the development of preventative and therapeutic strategies for AD is discussed. We anticipate that the new assay presented here will lead to the identification of other small molecules that regulate the activity of IDE toward insulin., (© 2018 The Author(s).)

Two new compounds (E)-2-(5,7-dibromo-3,3-dimethyl-3,4-dihydroacridin-1(2H)-ylidene)hydrazinecarbothiomide (3) and (E)-2-(5,7-dibromo-3,3-dimethyl-3,4-dhihydroacridin-1(2H)-ylidene)hydrazinecarboxamide (4) were synthesized and evaluated for their anticholinesterase activities. In vitro tests performed by NMR and Ellman's tests, pointed to a mixed kinetic mechanism for the inhibition of acetylcholinesterase (AChE). This result was corroborated through further docking and molecular dynamics studies, suggesting that the new compounds can work as gorge-spanning ligands by interacting with two different binding sites inside AChE. Also, in silico toxicity evaluation suggested that these new compounds can be less toxic than tacrine.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS) is a well-established method with a unique set of qualities including sensitivity, minute sample consumption, and label-free detection, all of which are highly desired in enzyme assays. On the other hand, the application of MALDI TOF MS is usually limited by high concentrations of MS-incompatible compounds in the reaction mixture such as salts or organic solvents. Here, we introduce kinetic and inhibition studies of β-secretase (BACE1), a key enzyme of the progression of Alzheimer's disease. Compatibility of the enzyme assay with MALDI TOF MS was achieved, providing both a complex protocol including a desalting step designed for rigorous kinetic studies and a simple mix-and-measure protocol designed for high-throughput inhibitor screening. In comparison with fluorescent or colorimetric assays, MALDI TOF MS represents a sensitive, fast, and label-free technique with minimal sample preparation. In contrast to other MS-based methodological approaches typically used in drug discovery processes, such as a direct injection MS or MS-coupled liquid chromatography or capillary electrophoresis, MALDI TOF MS enables direct analysis and is a highly suitable approach for high-throughput screening. The method's applicability is strongly supported by the high correlation of the acquired kinetic and inhibition parameters with data from the literature as well as from our previous research. Graphical abstract ᅟ.

Adenosine, hypoxanthine, xanthine, guanosine and inosine levels were assessed by HPLC, and the activity of related enzymes 5'-nucleotidase (5'-NT), adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) measured in frontal (FC), parietal (PC) and temporal (TC) cortices at different stages of disease progression in Alzheimer's disease (AD) and in age-matched controls. Significantly decreased levels of adenosine, guanosine, hypoxanthine and xanthine, and apparently less inosine, are found in FC from the early stages of AD; PC and TC show an opposing pattern, as adenosine, guanosine and inosine are significantly increased at least at determinate stages of AD whereas hypoxanthine and xanthine levels remain unaltered. 5'-NT is reduced in membranes and cytosol in FC mainly at early stages but not in PC, and only at advanced stages in cytosol in TC. ADA activity is decreased in AD when considered as a whole but increased at early stages in TC. Finally, PNP activity is increased only in TC at early stages. Purine metabolism alterations occur at early stages of AD independently of neurofibrillary tangles and β-amyloid plaques. Alterations are stage dependent and region dependent, the latter showing opposite patterns in FC compared with PC and TC. Adenosine is the most affected of the assessed purines., (© 2018 International Society of Neuropathology.)

Protein kinases are ubiquitously expressed as Serine/Threonine kinases, and play a crucial role in cellular activities. Protein kinases have evolved through stringent regulation mechanisms. Protein kinases are also involved in tauopathy, thus are important targets for developing Anti-Alzheimer's disease compounds. Structures with an indole scaffold turned out to be potent new leads. With the aim of developing new inhibitors for human protein kinase C, here we report the generation of four point 3D geometric featured pharmacophore model. In order to identify novel and potent PKCθ inhibitors, the pharmacophore model was screened against 80,000,00 compounds from various chemical databases such as., ZINC, SPEC, ASINEX, which resulted in 127 compound hits, and were taken for molecular docking filters (HTVS, XP docking). After in-depth analysis of binding patterns, induced fit docking (flexible) was employed for six compounds along with the cocrystallized inhibitor. Molecular docking study reveals that compound 6F found to be tight binder at the active site of PKCθ as compared to the cocrystal and has occupancy of 90 percentile. MM-GBSA also confirmed the potency of the compound 6F as better than cocrystal. Molecular dynamics results suggest that compound 6F showed good binding stability of active sites residues similar to cocrystal 7G compound. Present study corroborates the pharmacophore-based virtual screening, and finds the compound 6F as a potent Inhibitor of PKC, having therapeutic potential for Alzheimer's disease. Worldwide, 46.8 million people are believed to be living with Alzheimer's disease. When elderly population increases rapidly and neurodegenerative burden also increases in parallel, we project the findings from this study will be useful for drug developing efforts targeting Alzheimer's disease.