The synthesis and SAR of a series of 4-anilino-6,7-dialkoxyquinoline-3-carbonitrile inhibitors of epidermal growth factor receptor (EGF-R) kinase are described. Condensation of 3,4-dialkoxyanilines ...with ethyl (ethoxymethylene)cyanoacetate followed by thermal cyclization gave, regiospecifically, 6,7-dialkoxy-4-oxo-1,4-dihydroquinoline-3-carbonitriles. Chlorination (POCl3) followed by the reaction with substituted anilines furnished the 4-anilino-6,7-dialkoxyquinoline-3-carbonitrile inhibitors of EGF-R kinase. An alternate synthesis of these compounds starts with a methyl 3,4-dialkoxybenzoate. Nitration followed by reduction (Fe, NH4Cl, MeOH−H2O) gave a methyl 2-amino-4,5-dialkoxybenzoate. Amidine formation using DMF-acetal followed by cyclization using LiCH2CN furnished a 6,7-dialkoxy-4-oxo-1,4-dihydroquinoline-3-carbonitrile, which was transformed as before. Compounds containing acid, ester, amide, carbinol, and aldehyde groups at the 3-position of the quinoline ring were also prepared for comparison, as were several 1-anilino-6,7-dimethoxyisoquinoline-4-carbonitriles. The compounds were evaluated for their ability to inhibit the autophosphorylation of the catalytic domain of EGF-R. The SAR of these inhibitors with respect to the nature of the 6,7-alkoxy groups, the aniline substituents, and the substituent at the 3-position was studied. The compounds were further evaluated for their ability to inhibit the growth of cell lines that overexpress EGF-R or HER-2. It was found that 4-anilinoquinoline-3-carbonitriles are effective inhibitors of EGF-R kinase with activity comparable to the 4-anilinoquinazoline-based inhibitors. A new homology model of EGF-R kinase was constructed based on the X-ray structures of Hck and FGF receptor-1 kinase. The model suggests that with the quinazoline-based inhibitors, the N3 atom is hydrogen-bonded to a water molecule which, in turn, interacts with Thr 830. It is proposed that the quinoline-3-carbonitriles bind in a similar manner where the water molecule is displaced by the cyano group which interacts with the same Thr residue.
The nearby dwarf starburst galaxy NGC 5253 hosts a number of young, massive star clusters, the two youngest of which are centrally concentrated and surrounded by thermal radio emission (the “radio ...nebula”). To investigate the role of these clusters in the starburst energetics, we combine new and archival Hubble Space Telescope images of NGC 5253 with wavelength coverage from 1500 Å to 1.9 μm in 13 filters. These include Hα, Pβ, and Pα, and the imaging from the Hubble Treasury Program LEGUS (Legacy Extragalactic UV Survey). The extraordinarily well-sampled spectral energy distributions enable modeling with unprecedented accuracy the ages, masses, and extinctions of the nine optically brightest clusters (MV < -8.8) and the two young radio nebula clusters. The clusters have ages ∼1-15 Myr and masses ∼1 × 104-2.5 × 105 M⊙. The clusters’ spatial location and ages indicate that star formation has become more concentrated toward the radio nebula over the last ∼15 Myr. The most massive cluster is in the radio nebula; with a mass ∼2.5 × 105 M⊙ and an age ∼1 Myr, it is 2-4 times less massive and younger than previously estimated. It is within a dust cloud with AV ∼ 50 mag, and shows a clear near-IR excess, likely from hot dust. The second radio nebula cluster is also ∼1 Myr old, confirming the extreme youth of the starburst region. These two clusters account for about half of the ionizing photon rate in the radio nebula, and will eventually supply about 2/3 of the mechanical energy in present-day shocks. Additional sources are required to supply the remaining ionizing radiation, and may include very massive stars. Based on observations obtained with the NASA/ESA Hubble Space Telescope, at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.
In people with genetic forms of Alzheimer's disease, such as in Down syndrome and autosomal-dominant Alzheimer's disease, pathological changes specific to Alzheimer's disease (ie, accumulation of ...amyloid and tau) occur in the brain at a young age, when comorbidities related to ageing are not present. Studies including these cohorts could, therefore, improve our understanding of the early pathogenesis of Alzheimer's disease and be useful when designing preventive interventions targeted at disease pathology or when planning clinical trials. We compared the magnitude, spatial extent, and temporal ordering of tau spread in people with Down syndrome and autosomal-dominant Alzheimer's disease.
In this cross-sectional observational study, we included participants (aged ≥25 years) from two cohort studies. First, we collected data from the Dominantly Inherited Alzheimer's Network studies (DIAN-OBS and DIAN-TU), which include carriers of autosomal-dominant Alzheimer's disease genetic mutations and non-carrier familial controls recruited in Australia, Europe, and the USA between 2008 and 2022. Second, we collected data from the Alzheimer Biomarkers Consortium–Down Syndrome study, which includes people with Down syndrome and sibling controls recruited from the UK and USA between 2015 and 2021. Controls from the two studies were combined into a single group of familial controls. All participants had completed structural MRI and tau PET (18F-flortaucipir) imaging. We applied Gaussian mixture modelling to identify regions of high tau PET burden and regions with the earliest changes in tau binding for each cohort separately. We estimated regional tau PET burden as a function of cortical amyloid burden for both cohorts. Finally, we compared the temporal pattern of tau PET burden relative to that of amyloid.
We included 137 people with Down syndrome (mean age 38·5 years SD 8·2, 74 54% male, and 63 46% female), 49 individuals with autosomal-dominant Alzheimer's disease (mean age 43·9 years 11·2, 22 45% male, and 27 55% female), and 85 familial controls, pooled from across both studies (mean age 41·5 years 12·1, 28 33% male, and 57 67% female), who satisfied the PET quality-control procedure for tau-PET imaging processing. 134 (98%) people with Down syndrome, 44 (90%) with autosomal-dominant Alzheimer's disease, and 77 (91%) controls also completed an amyloid PET scan within 3 years of tau PET imaging. Spatially, tau PET burden was observed most frequently in subcortical and medial temporal regions in people with Down syndrome, and within the medial temporal lobe in people with autosomal-dominant Alzheimer's disease. Across the brain, people with Down syndrome had greater concentrations of tau for a given level of amyloid compared with people with autosomal-dominant Alzheimer's disease. Temporally, increases in tau were more strongly associated with increases in amyloid for people with Down syndrome compared with autosomal-dominant Alzheimer's disease.
Although the general progression of amyloid followed by tau is similar for people Down syndrome and people with autosomal-dominant Alzheimer's disease, we found subtle differences in the spatial distribution, timing, and magnitude of the tau burden between these two cohorts. These differences might have important implications; differences in the temporal pattern of tau accumulation might influence the timing of drug administration in clinical trials, whereas differences in the spatial pattern and magnitude of tau burden might affect disease progression.
None.
The human immunodeficiency virus 1 (HIV-1) protease (PR) is an aspartyl protease essential for HIV-1 viral infectivity. HIV-1 PR has one catalytic site formed by the homodimeric enzyme. We chemically ...synthesized fully active HIV-1 PR using modern ligation methods. When complexed with the classic substrate-derived inhibitors JG-365 and MVT-101, the synthetic HIV-1 PR formed crystals that diffracted to 1.04- and 1.2-Å resolution, respectively. These atomic-resolution structures revealed additional structural details of the HIV-1 PR's interactions with its active site ligands. Heptapeptide inhibitor JG-365, which has a hydroxyethylamine moiety in place of the scissile bond, binds in two equivalent antiparallel orientations within the catalytic groove, whereas the reduced isostere hexapeptide MVT-101 binds in a single orientation. When JG-365 was converted into the natural peptide substrate for molecular dynamic simulations, we found putative catalytically competent reactant states for both lytic water and direct nucleophilic attack mechanisms. Moreover, free energy perturbation calculations indicated that the insertion of catalytic water into the catalytic site is an energetically favorable process.
Background
The biological processes that are disrupted in the Alzheimer’s disease (AD) brain remain incompletely understood. We recently performed a proteomic analysis of >2000 brains to better ...understand these changes, which highlighted alterations in astrocytes and microglia as likely key drivers of disease.
Method
Here, we extend this analysis by analyzing >1000 brain tissues using a tandem mass tag mass spectrometry (TMT‐MS) pipeline, which allowed us to nearly triple the number of quantified proteins across cases. We analyzed this deeper dataset using protein co‐expression network analysis to identify biological processes altered in AD.
Result
We identified new protein co‐expression modules that were highly preserved across cohorts and brain regions, and strongly altered in AD. Nearly half of the protein co‐expression modules, including modules significantly altered in AD, were not observed in RNA networks from the same cohorts and brain regions, highlighting the proteopathic nature of AD. Two such AD‐associated modules unique to the proteomic network included a module related to MAPK signaling and metabolism, and a module related to the matrisome. Analysis of paired genetic and proteomic data within subjects showed that expression level of the matrisome module was influenced by the ApoE4 genotype, but was not related to the rate of cognitive decline after adjustment for neuropathology. In contrast, the MAPK/metabolism module was strongly associated with the rate of cognitive decline after adjustment for neuropathology.
Conclusion
Disease‐associated modules unique to the proteome are sources of promising therapeutic targets and biomarkers for AD.
Background
The repeated failures of amyloid‐targeting therapies have underscored the need for additional biomarkers of Alzheimer’s disease (AD) that reflect its complex multi‐network dysfunction. ...Using a network‐based proteomic approach, we previously defined a wide range of protein system alterations in the AD brain. In this study, we integrated these brain networks with proteomic analysis of cerebrospinal fluid (CSF), resulting in the identification of CSF biomarker panels reflective of diverse pathophysiology within the AD brain.
Methods
Using quantitative liquid chromatography coupled to tandem mass spectrometry (LC‐MS/MS), we comparatively analyzed the CSF proteomes of 40 samples (20 controls, 20 AD). Differential expression analysis resolved CSF proteins significantly altered in AD. These CSF biomarkers were mapped to proteomic networks derived from 48 postmortem brain tissues comprising control, asymptomatic AD (AsymAD), AD, and other neurodegenerative diseases. Validation was performed in an independent CSF cohort of 96 control, AsymAD, and AD samples using high‐throughput proteomic methods.
Results
We identified >3,500 proteins across the initial 40 CSF samples and >12,000 proteins across the 48 postmortem brain tissues. Co‐expression network analysis of the brain tissues yielded 44 protein modules, nearly half of which correlated significantly to AD neuropathology. Fifteen modules robustly overlapped with proteins quantified in the CSF, including 271 CSF markers highly altered in AD. These 15 overlapping modules were collapsed into five panels of brain‐linked fluid markers representing a variety of cortical functions. Neuron‐enriched synaptic and metabolic panels demonstrated decreased levels in the AD brain but increased levels in diseased CSF. Conversely, glial‐enriched myelination and immunity panels were highly increased in both the brain and CSF. Validation of these findings in an independent CSF cohort of control, AsymAD, and AD samples remarkably demonstrated panel alterations in the early, asymptomatic stages of disease. In fact, several panel markers appeared to stratify subpopulations within this preclinical cohort.
Conclusion
These brain‐linked CSF biomarker panels represent a promising step toward a comprehensive physiological tool that could enhance the therapeutic management of AD.
Abstract
Background
The repeated failures of amyloid‐targeting therapies have underscored the need for additional biomarkers of Alzheimer’s disease (AD) that reflect its complex multi‐network ...dysfunction. Using a network‐based proteomic approach, we previously defined a wide range of protein system alterations in the AD brain. In this study, we integrated these brain networks with proteomic analysis of cerebrospinal fluid (CSF), resulting in the identification of CSF biomarker panels reflective of diverse pathophysiology within the AD brain.
Methods
Using quantitative liquid chromatography coupled to tandem mass spectrometry (LC‐MS/MS), we comparatively analyzed the CSF proteomes of 40 samples (20 controls, 20 AD). Differential expression analysis resolved CSF proteins significantly altered in AD. These CSF biomarkers were mapped to proteomic networks derived from 48 postmortem brain tissues comprising control, asymptomatic AD (AsymAD), AD, and other neurodegenerative diseases. Validation was performed in an independent CSF cohort of 96 control, AsymAD, and AD samples using high‐throughput proteomic methods.
Results
We identified >3,500 proteins across the initial 40 CSF samples and >12,000 proteins across the 48 postmortem brain tissues. Co‐expression network analysis of the brain tissues yielded 44 protein modules, nearly half of which correlated significantly to AD neuropathology. Fifteen modules robustly overlapped with proteins quantified in the CSF, including 271 CSF markers highly altered in AD. These 15 overlapping modules were collapsed into five panels of brain‐linked fluid markers representing a variety of cortical functions. Neuron‐enriched synaptic and metabolic panels demonstrated decreased levels in the AD brain but increased levels in diseased CSF. Conversely, glial‐enriched myelination and immunity panels were highly increased in both the brain and CSF. Validation of these findings in an independent CSF cohort of control, AsymAD, and AD samples remarkably demonstrated panel alterations in the early, asymptomatic stages of disease. In fact, several panel markers appeared to stratify subpopulations within this preclinical cohort.
Conclusion
These brain‐linked CSF biomarker panels represent a promising step toward a comprehensive physiological tool that could enhance the therapeutic management of AD.
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