pyrimidinones and Alzheimer-Disease

Autophagy is the mass degradation system that removes long-lived proteins and malfunctioning organelles within the cell. Dysfunctional autophagic processes can cause various diseases such as cancer and neurodegenerative disorders, but the underlying mechanisms responsible for such events remain undefined. Small molecules that control autophagy could be powerful tools to reveal autophagy mechanisms, and to develop treatments for autophagy-related diseases including Alzheimer's disease, Parkinson's disease and various cancer types. This review discusses the small molecules that have been identified to control autophagy and how they can be used to understand signaling pathways important for autophagy in the context of chemical genomics.

Topics: Alzheimer Disease; Autophagy; Cell Death; Humans; Neurodegenerative Diseases; Parkinson Disease; Proteins; Pyrimidinones; Signal Transduction; Small Molecule Libraries; Structure-Activity Relationship; Thiophenes

PF-04447943 is a potent, selective phosphodiesterase 9A (PDE9A) inhibitor that elevates guanoscine 3',5' - cyclic monophosphate (cGMP) in brain and cerebrospinal fluid. PDE9A inhibition enhances synaptic plasticity and improves memory in preclinical cognition models, and prevents decreases in dendritic spine density in transgenic mice that overexpress amyloid precursor protein (APP) leading to high levels of amyloid beta (Aβ) production (Tg2576).. This Phase 2 multicenter study was designed to assess the efficacy, safety and pharmacokinetics of PF-04447943 compared with placebo in mild to moderate probable Alzheimer's disease (AD).. Subjects in overall good health with Mini Mental State Examination (MMSE) scores of 14-26 were randomized to 12 weeks treatment with PF-04447943 25 mg q12h (n=91) or placebo (n=100). Concomitant acetylcholinesterase inhibitor or memantine use was excluded. The primary outcome was the Alzheimer's Disease Assessment Scale - cognitive subscale (ADAS-cog). The Neuropsychiatric Inventory (NPI), Clinical Global Impression-Improvement scale (CGI-I) and standard safety measures were secondary outcomes.. Completion rates were similar, 87% PF-04447943 vs 92% placebo. At week 12 the mean (SE) baseline adjusted decrease from baseline in ADAS cog for PF-04447943-treated patients was -1.91 (0.54). Placebo treated patients had a change of -1.60 (0.50). The difference between treatments was -0.31 (90% CI of -1.52, 0.90). Corresponding values for the NPI were -2.86 (0.72) vs -2.70 (0.67) with a treatment difference of -0.16 (90% CI of -1.78, 1.48). Neither these changes nor the distribution of CGI-I scores were statistically significantly different between groups. The incidence of serious adverse events (AEs) was similar between groups with 2 deaths in the placebo group. The PF-04447943 group reported more gastrointestinal AEs including diarrhea (5.5% vs 3%) and nausea (5.5% vs 1%) and had a higher rate of discontinuation due to AEs (6.6% vs 2%).. Although generally safe and well-tolerated, 12 weeks PF-04447943 treatment did not improve cognition, behavior, and global change compared with placebo.

Topics: Aged; Aged, 80 and over; Alzheimer Disease; Cognition Disorders; Double-Blind Method; Female; Humans; Male; Mental Status Schedule; Middle Aged; Neuropsychological Tests; Outcome Assessment, Health Care; Phosphodiesterase Inhibitors; Pyrazoles; Pyrimidinones; Treatment Outcome

Alzheimer's disease (AD) pathology is associated with complex interactions among multiple factors, involving an intertwined network of various signaling pathways. The polypharmacological approach is an emerging therapeutic strategy that has been proposed to overcome the multifactorial nature of AD by targeting multiple pathophysiological factors including amyloid-β (Aβ) and phosphorylated tau. We evaluated a blood-brain barrier penetrating phosphodiesterase 5 (PDE5) inhibitor, mirodenafil (5-ethyl-2-7-n-propyl-3,5-dihydrro-4H-pyrrolo[3,2-d]pyrimidin-4-one), for its therapeutic effects on AD with polypharmacological properties.. To evaluate the potential of mirodenafil as a disease-modifying AD agent, mirodenafil was administered to test its effects on the cognitive behaviors of the APP-C105 AD mouse model using the Morris water maze and passive avoidance tests. To investigate the mechanisms of action that underlie the beneficial disease-modifying effects of mirodenafil, human neuroblastoma SH-SY5Y cells and mouse hippocampal HT-22 cells were used to show mirodenafil-induced alterations associated with the cyclic guanosine monophosphate (cGMP)/cGMP-dependent protein kinase (PKG)/cAMP-responsive element-binding protein (CREB) pathway, apoptotic cell death, tau phosphorylation, amyloidogenesis, the autophagy-lysosome pathway, glucocorticoid receptor (GR) transcriptional activity, and the Wnt/β-catenin signaling.. Here, mirodenafil is demonstrated to improve cognitive behavior in the APP-C105 mouse model. Mirodenafil not only reduced the Aβ and phosphorylated tau burdens in vivo, but also ameliorated AD pathology induced by Aβ through the modulation of the cGMP/PKG/CREB signaling pathway, glycogen synthase kinase 3β (GSK-3β) activity, GR transcriptional activity, and the Wnt/β-catenin signaling in neuronal cells. Interestingly, homodimerization and nuclear localization of GR were inhibited by mirodenafil, but not by other PDE5 inhibitors. In addition, only mirodenafil reduced the expression levels of the Wnt antagonist Dickkopf-1 (Dkk-1), thus activating the Wnt/β-catenin signaling.. These findings strongly suggest that the PDE5 inhibitor mirodenafil shows promise as a potential polypharmacological drug candidate for AD treatment, acting on multiple key signaling pathways involved in amyloid deposition, phosphorylated tau burden, the cGMP/PKG/CREB pathway, GSK-3β kinase activity, GR signaling, and the Wnt/β-catenin signaling. Mirodenafil administration to the APP-C105 AD mouse model also improved cognitive behavior, demonstrating the potential of mirodenafil as a polypharmacological AD therapeutic agent.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Animals; beta Catenin; Cyclic GMP; Disease Models, Animal; Glycogen Synthase Kinase 3 beta; Humans; Mice; Neuroblastoma; Phosphodiesterase 5 Inhibitors; Phosphorylation; Pyrimidinones; Sulfonamides; tau Proteins

Topics: 3',5'-Cyclic-AMP Phosphodiesterases; Alzheimer Disease; Dose-Response Relationship, Drug; Drug Design; Enzyme Inhibitors; Humans; Molecular Docking Simulation; Molecular Structure; Neuroprotective Agents; Pyrazoles; Pyrimidinones; Structure-Activity Relationship

Intracerebroventricular (icv) streptozotocin (STZ) injection decreases cerebral insulin signal pathway function and produces multiple effects that resemble the molecular, pathological, and behavioural features of Sporadic Alzheimer's disease (SAD). We previously reported that yonkenafil (yonk), the analogue of sildenafil and a novel PDE5 inhibitor exerts an anti-amyloidogenesis effect by regulating the Aβ level and inhibiting the expression of β-amyloid precursor protein in the APP/PS1 transgenic mice model. In this study, the effects of yonk on cognitive behaviors as well as the pathological features in streptozotocin-induced SAD rat model were investigated. The results demonstrated that administration of yonk at doses of 3 and 10 mg/kg for three weeks significantly improved cognitive deficits, attenuated STZ-induced neuronal death, inhibited the over-activation of microglia and astrocytes and the levels of pro-inflammatory markers, as well as decreased PDE5 protein expression in the hippocampus. Furthermore, yonk (3 mg/kg) notably prevented changes in tau hyperphosphorylation, decreased IRS-1and JNK phosphorylation and increased the GSK3β (ser9) phosphorylation induced by STZ. In summary, these data suggested that yonk significantly reversed STZ-induced memory deficits by inhibiting the over-activation of microglia and astrocytes, as well as ameliorated the levels of pro-inflammatory makers and tau hyperphosphorylation through regulating GSK3β signalling pathway.

Topics: Alzheimer Disease; Animals; Disease Models, Animal; Encephalitis; Insulin; Male; Phosphodiesterase 5 Inhibitors; Phosphorylation; Pyrimidinones; Pyrroles; Rats, Wistar; Streptozocin; tau Proteins

Topics: Alzheimer Disease; Amyloid beta-Peptides; Animals; Antibodies; Disease Models, Animal; Disease Progression; Entorhinal Cortex; Humans; Mice; Models, Biological; Naphthalenes; Pyrimidinones; tau Proteins; Treatment Failure

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.

Topics: Alzheimer Disease; Amino Acids; Amyloid Precursor Protein Secretases; Drug Evaluation, Preclinical; HEK293 Cells; Heterocyclic Compounds, 2-Ring; Humans; Kinetics; Picolinic Acids; Pyrimidinones; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

Discovery of multitarget-directed ligands (MTDLs), targeting different factors simultaneously to control the complicated pathogenesis of Alzheimer's disease (AD), has become an important research area in recent years. Both phosphodiesterase 9A (PDE9A) and butyrylcholinesterase (BuChE) inhibitors could participate in different processes of AD to attenuate neuronal injuries and improve cognitive impairments. However, research on MTDLs combining the inhibition of PDE9A and BuChE simultaneously has not been reported yet. In this study, a series of novel pyrazolopyrimidinone-rivastigmine hybrids were designed, synthesized, and evaluated in vitro. Most compounds exhibited remarkable inhibitory activities against both PDE9A and BuChE. Compounds 6c and 6f showed the best IC

Topics: Alzheimer Disease; Amyloid beta-Peptides; Antioxidants; Butyrylcholinesterase; Cell Line, Tumor; Cholinesterase Inhibitors; Drug Design; Drug Evaluation, Preclinical; Humans; Inhibitory Concentration 50; Ligands; Models, Molecular; Molecular Docking Simulation; Molecular Structure; Oxidative Stress; Peptide Fragments; Phosphodiesterase Inhibitors; Protein Aggregation, Pathological; Protein Conformation; Pyrazolones; Pyrimidinones; Rivastigmine

The targeting of two independent but synergistic enzymatic activities, histone deacetylases (HDACs, class I and HDAC6) and phosphodiesterase 5 (PDE5), has recently been validated as a potentially novel therapeutic approach for Alzheimer's disease (AD). Here we report the discovery of a new first-in-class small-molecule (CM-414) that acts as a dual inhibitor of PDE5 and HDACs. We have used this compound as a chemical probe to validate this systems therapeutics strategy, where an increase in the activation of cAMP/cGMP-responsive element-binding protein (CREB) induced by PDE5 inhibition, combined with moderate HDAC class I inhibition, leads to efficient histone acetylation. This molecule rescued the impaired long-term potentiation evident in hippocampal slices from APP/PS1 mice. Chronic treatment of Tg2576 mice with CM-414 diminished brain Aβ and tau phosphorylation (pTau) levels, increased the inactive form of GSK3β, reverted the decrease in dendritic spine density on hippocampal neurons, and reversed their cognitive deficits, at least in part by inducing the expression of genes related to synaptic transmission. Thus, CM-414 may serve as the starting point to discover balanced dual inhibitors with an optimal efficacy and safety profile for clinical testing on AD patients.

Topics: Alzheimer Disease; Animals; Behavior, Animal; Disease Models, Animal; Female; Hippocampus; Histone Deacetylase Inhibitors; Mice; Mice, Transgenic; Motor Activity; Neuronal Plasticity; Phosphodiesterase 5 Inhibitors; Primary Cell Culture; Pyrazoles; Pyrimidinones

The initial structure activity relationships around an isoindoline uHTS hit will be described. Information gleaned from ligand co-crystal structures allowed for rapid refinements in both MARK potency and kinase selectivity. These efforts allowed for the identification of a compound with properties suitable for use as an in vitro tool compound for validation studies on MARK as a viable target for Alzheimer's disease.

Topics: Alzheimer Disease; Cell Line; Crystallography, X-Ray; Dose-Response Relationship, Drug; Drug Design; Humans; Models, Molecular; Molecular Structure; Protein Kinase Inhibitors; Protein Serine-Threonine Kinases; Pyrimidinones; Pyrroles; Structure-Activity Relationship

Attempts to optimize pharmacokinetic properties in a promising series of pyrrolopyrimidinone MARK inhibitors for the treatment of Alzheimer's disease are described. A focus on physical properties and ligand efficiency while prosecuting this series afforded key tool compounds that revealed a large discrepancy in the rat in vitro-in vivo DMPK (Drug Metabolism/Pharmacokinetics) correlation. These differences prompted an in vivo rat disposition study employing a radiolabeled representative of the series, and the results from this experiment justified the termination of any further optimization efforts.

Topics: Alzheimer Disease; Animals; Dose-Response Relationship, Drug; Humans; Isoenzymes; Molecular Structure; Protein Kinase Inhibitors; Protein Serine-Threonine Kinases; Pyrimidinones; Pyrroles; Rats; Structure-Activity Relationship

Recently, phosphodiesterase-9 (PDE9) inhibitors and biometal-chelators have received much attention as potential therapeutics for the treatment of Alzheimer's disease (AD). Here, we designed, synthesized, and evaluated a novel series of PDE9 inhibitors with the ability to chelate metal ions. The bioassay results showed that most of these molecules strongly inhibited PDE9 activity. Compound 16 showed an IC50 of 34 nM against PDE9 and more than 55-fold selectivity against other PDEs. In addition, this compound displayed remarkable metal-chelating capacity and a considerable ability to halt copper redox cycling. Notably, in comparison to the reference compound clioquinol, it inhibited metal-induced Aβ(1-42) aggregation more effectively and promoted greater disassembly of the highly structured Aβ fibrils generated through Cu(2+)-induced Aβ aggregation. These activities of 16, together with its favorable blood-brain barrier permeability, suggest that 16 may be a promising compound for treatment of AD.

Topics: 3',5'-Cyclic-AMP Phosphodiesterases; Alzheimer Disease; Amyloid beta-Peptides; Blood-Brain Barrier; Cell Line, Tumor; Cell Survival; Chelating Agents; Clioquinol; Copper; Humans; Microscopy, Electron, Transmission; Molecular Docking Simulation; Peptide Fragments; Permeability; Phosphodiesterase Inhibitors; Protein Structure, Tertiary; Pyrazoles; Pyrimidinones

This paper describes the synthesis and evaluation of new dihydropyrimidinone (DHPM)-derived selenoesters as potential multi-targeted agents for the treatment of Alzheimer's disease. A series of DHPM-derived selenoesters were obtained with high structural diversity through a short and modular synthetic route. The antioxidant activity was evaluated by TBARS and iron chelation assays. These compounds were also evaluated as acetylcholinesterase inhibitors (AChEi). The compounds demonstrated good antioxidant activity, since they presented excellent lipid peroxidation inhibition and good iron chelation activity. In addition, they showed acetylcholinesterase inhibition activity and some of them presented activity superior to that of the standard drug galantamine. The in silico predictions showed that the compound 1h may present a good pharmacokinetic profile. Therefore, the series of DHPM-derived selenoesters described herein displayed good potential for the development of antioxidant and anticholinesterasic agents in the search for new multi-targeted therapeutics for the treatment of Alzheimer's disease.

Topics: Alzheimer Disease; Antioxidants; Cholinesterase Inhibitors; Dose-Response Relationship, Drug; Esters; Humans; Molecular Structure; Organoselenium Compounds; Pyrimidinones; Structure-Activity Relationship

In this paper we report the design, synthesis and evaluation of a series of seleno-dihydropyrimidinones as potential multi-targeted therapeutics for Alzheimer's disease. The compounds show excellent results as acetylcholinesterase inhibitors, being as active as the standard drug. All these compounds also show very good antioxidant activity through different mechanisms of action.

Topics: Alzheimer Disease; Antioxidants; Cholinesterase Inhibitors; Drug Design; Humans; Molecular Targeted Therapy; Pyrimidinones; Selenium

The development of early diagnostic and prognostic tools for the visualization of amyloid-β (Aβ) deposits is one important focus of current imaging research. In patients with Alzheimer's disease (AD), non-invasive and efficient detection of soluble and aggregated Aβ is important to determine the immediate success of intervention trails. The novel near infrared-fluorescence (NIRF) probe THK-265 efficiently penetrates the blood-brain barrier and has a strong and efficient binding to cerebral Aβ. Ex vivo microscopy of i) THK-265-labeling of plaques in paraffin-embedded tissue and ii) cerebral cryo-sections after intravenous injection of THK-265 confirmed a systematic increase of the NIRF signal corresponding to Aβ plaque number and size during disease progression. Furthermore, we investigated different stages of plaque formation in amyloid-β protein precursor transgenic mice in vivo after intravenous application of THK-265 to evaluate different aggregation levels with NIRF signals. The intensity of the NIRF signal correlated well with the plaque burden, indicating its utility for direct monitoring of Aβ aggregation progression. In summary, our results support the use of the NIRF probe THK-265 for the diagnosis and direct visualization of amyloid deposits and open the possibility for efficient, pre-symptomatic monitoring of Aβ deposition in the aging brain.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Brain; Disease Models, Animal; Disease Progression; Fluorescent Dyes; Mice; Mice, Transgenic; Plaque, Amyloid; Pyrimidinones; Thiones

Alzheimer's disease pathology has demonstrated amyloid plaque formation associated with plasma membranes and the presence of intracellular amyloid-beta (A beta) accumulation in specific vesicular compartments. This suggests that lipid composition in different compartments may play a role in A beta aggregation. To test this hypothesis, we have isolated cellular membranes from human brain to evaluate A beta 40/42-lipid interactions. Plasma, endosomal, lysosomal, and Golgi membranes were isolated using sucrose gradients. Electron microscopy demonstrated that A beta fibrillogenesis is accelerated in the presence of plasma and endosomal and lysosomal membranes with plasma membranes inducing an enhanced surface organization. Alternatively, interaction of A beta with Golgi membranes fails to progress to fibril formation, suggesting that A beta-Golgi head group interaction stabilizes A beta. Fluorescence spectroscopy using the environment-sensitive probes 1,6-diphenyl-1,3,5-hexatriene, laurdan, N-epsilon-dansyl-L-lysine, and merocyanine 540 demonstrated variations in the inherent lipid properties at the level of the fatty acyl chains, glycerol backbone, and head groups, respectively. Addition of A beta 40/42 to the plasma and endosomal and lysosomal membranes decreases the fluidity not only of the fatty acyl chains but also the head group space, consistent with A beta insertion into the bilayer. In contrast, the Golgi bilayer fluidity is increased by A beta 40/42 binding which appears to result from lipid head group interactions and the production of interfacial packing defects.

Topics: Aged; Aged, 80 and over; Alzheimer Disease; Amyloid beta-Peptides; Anisotropy; Brain; Cell Membrane; Dimerization; Endosomes; Fluorescent Dyes; Golgi Apparatus; Humans; Lipids; Lysosomes; Male; Microscopy, Electron; Models, Chemical; Peptides; Phospholipids; Protein Binding; Pyrimidinones; Spectrometry, Fluorescence; Spectrophotometry

Using [18F]setoperone and positron emission tomography (PET), alterations in serotonergic 5-HT2 receptor binding were studied in cerebral cortex of nine unmedicated patients with probable Alzheimer's disease and 37 healthy controls. The kinetics of unchanged radioligand in plasma and 18F-radioactivity in blood and brain were obtained for 90 min following tracer injection. The specific binding of [18F]setoperone to 5-HT2 receptors in the cerebral cortex was quantitated by subtraction using cerebellum as reference. In controls, a significant reduction in specific binding was associated with age and similar linear regression slopes were obtained in all the cortical regions studied. No significant difference was observed between patients with Alzheimer's disease and age-matched controls in the injected mass of setoperone, percentage of unmetabolized [18F]setoperone in plasma, 18F-radioactivity in blood fractions and cerebellar 18F-radioactivity concentration, indicating similar non-specific brain kinetics and metabolism of the radioligand. In contrast, there was a significant reduction in specific [18F]setoperone binding in the cerebral cortex in patients with Alzheimer's disease relative to control values (temporal, 69%; frontal, 69%; parietal, 55%; temporo-parietal, 54%; occipital cortex, 35%). The results demonstrate that the loss in 5-HT2 receptor binding in the cerebral cortex of patients with Alzheimer's disease, long documented by post-mortem studies, can now be assessed in vivo using PET.

Topics: Aged; Alzheimer Disease; Cerebral Cortex; Female; Fluorine Radioisotopes; Humans; Male; Middle Aged; Pyrimidinones; Receptors, Serotonin; Tomography, Emission-Computed, Single-Photon