This textbook introduces students to the critical role of the US intelligence community within the wider national security decision-making and political process. Intelligence in the National Security ...Enterprise defines what intelligence is and what intelligence agencies do, but the emphasis is on showing how intelligence serves the policymaker. Roger Z. George draws on his thirty-year CIA career and more than a decade of teaching at both the undergraduate and graduate level to reveal the real world of intelligence. Intelligence support is examined from a variety of perspectives to include providing strategic intelligence, warning, daily tactical support to policy actions as well as covert action. The book includes useful features for students and instructors such as excerpts and links to primary-source documents, suggestions for further reading, and a glossary.
RAS proteins are important direct activators of p110α, p110γ, and p110δ type I phosphoinositide 3-kinases (PI3Ks), interacting via an amino-terminal RAS-binding domain (RBD). Here, we investigate the ...regulation of the ubiquitous p110β isoform of PI3K, implicated in G-protein-coupled receptor (GPCR) signaling, PTEN-loss-driven cancers, and thrombocyte function. Unexpectedly, RAS is unable to interact with p110β, but instead RAC1 and CDC42 from the RHO subfamily of small GTPases bind and activate p110β via its RBD. In fibroblasts, GPCRs couple to PI3K through Dock180/Elmo1-mediated RAC activation and subsequent interaction with p110β. Cells from mice carrying mutations in the p110β RBD show reduced PI3K activity and defective chemotaxis, and these mice are resistant to experimental lung fibrosis. These findings revise our understanding of the regulation of type I PI3K by showing that both RAS and RHO family GTPases directly regulate distinct ubiquitous PI3K isoforms and that RAC activates p110β downstream of GPCRs.
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•Unlike p110α, p110γ, and p110δ PI3K isoforms, RAS is unable to interact with p110β•The RHO family GTPases RAC1 and CDC42 directly bind and activate p110β via its RBD•GPCRs couple to PI3K via Dock180/Elmo1-mediated RAC activation and binding to p110β•Mice with RBD mutant p110β are resistant to experimental lung fibrosis
RAS proteins bind and activate multiple PI3K isoforms. The p110β isoform of PI3K, however, is instead activated by the binding of RHO family members RAC and CDC42. Blocking this interaction blunts GPCR-mediated cellular chemotaxis and confers resistance to lung fibrosis.
Hepatocytes provide an integrated model to study drug metabolism and disposition. As a result of a loss of polarity or a significant decrease in the expression of enzymes and transporters, suspended ...and sandwich-cultured hepatocytes have limitations in determining hepatocellular drug concentrations. Underprediction of the extent of glucuronidation is also a concern for these hepatocyte models. Faldaprevir is a hepatitis C virus protease inhibitor in late-stage development that has demonstrated significant liver enrichment in in vivo rat models based on quantitative whole-body autoradiography (QWBA) and liver-to-plasma area under-the-curve ratio. In bile duct cannulated rats, the primary biliary metabolite was a glucuronide. Owing to ethical concerns, it is difficult to assess liver enrichment in humans, and a lack of in vitro and in vivo correlation of glucuronidation has been reported. The current study was conducted to verify whether a hepatocyte model, rat HepatoPac, could overcome some of these limitations and provide validity for follow-up studies with human HepatoPac. With rat HepatoPac, liver enrichment values averaged 34-fold and were consistent with rat QWBA (26.8-fold) and in vivo data (42-fold). In contrast, liver enrichment in suspended hepatocytes was only 2.8-fold. Furthermore, the extent of faldaprevir glucuronidation in HepatoPac studies was in agreement with in vivo results, with glucuronidation as the major pathway (96%). Suspended rat hepatocytes did not generate the glucuronide or two key hydroxylated metabolites that were observed in vivo. Overall, our studies suggest that HepatoPac is a promising in vitro model to predict in vivo liver enrichment and metabolism, especially for glucuronidation, and has demonstrated superiority over suspended hepatocytes.
The mechanistic foundation of vascular maturation is still largely unknown. Several human pathologies are characterized by deregulated angiogenesis and unstable blood vessels. Solid tumors, for ...instance, get their nourishment from newly formed structurally abnormal vessels which present wide and irregular interendothelial junctions. Expression and clustering of the main endothelial-specific adherens junction protein, VEC (vascular endothelial cadherin), upregulate genes with key roles in endothelial differentiation and stability.
We aim at understanding the molecular mechanisms through which VEC triggers the expression of a set of genes involved in endothelial differentiation and vascular stabilization.
We compared a VEC-null cell line with the same line reconstituted with
wild-type cDNA. VEC expression and clustering upregulated endothelial-specific genes with key roles in vascular stabilization including
, vascular endothelial-protein tyrosine phosphatase (
), and von Willebrand factor (
). Mechanistically, VEC exerts this effect by inhibiting polycomb protein activity on the specific gene promoters. This is achieved by preventing nuclear translocation of FoxO1 (Forkhead box protein O1) and β-catenin, which contribute to PRC2 (polycomb repressive complex-2) binding to promoter regions of
,
, and
. VEC/β-catenin complex also sequesters a core subunit of PRC2 (Ezh2 enhancer of zeste homolog 2) at the cell membrane, preventing its nuclear translocation. Inhibition of Ezh2/VEC association increases Ezh2 recruitment to
,
, and
promoters, causing gene downregulation. RNA sequencing comparison of VEC-null and VEC-positive cells suggested a more general role of VEC in activating endothelial genes and triggering a vascular stability-related gene expression program. In pathological angiogenesis of human ovarian carcinomas, reduced VEC expression paralleled decreased levels of claudin-5 and VE-PTP.
These data extend the knowledge of polycomb-mediated regulation of gene expression to endothelial cell differentiation and vessel maturation. The identified mechanism opens novel therapeutic opportunities to modulate endothelial gene expression and induce vascular normalization through pharmacological inhibition of the polycomb-mediated repression system.
Shprintzen-Goldberg syndrome (SGS) is a multisystemic connective tissue disorder, with considerable clinical overlap with Marfan and Loeys-Dietz syndromes. These syndromes have commonly been ...associated with enhanced TGF-β signaling. In SGS patients, heterozygous point mutations have been mapped to the transcriptional co-repressor SKI, which is a negative regulator of TGF-β signaling that is rapidly degraded upon ligand stimulation. The molecular consequences of these mutations, however, are not understood. Here we use a combination of structural biology, genome editing, and biochemistry to show that SGS mutations in SKI abolish its binding to phosphorylated SMAD2 and SMAD3. This results in stabilization of SKI and consequently attenuation of TGF-β responses, both in knockin cells expressing an SGS mutation and in fibroblasts from SGS patients. Thus, we reveal that SGS is associated with an attenuation of TGF-β-induced transcriptional responses, and not enhancement, which has important implications for other Marfan-related syndromes.
The pharmacokinetics, mass balance, and metabolite profiles of faldaprevir, a selective peptide-mimetic hepatitis C virus NS3/NS4 protease inhibitor, were assessed at steady state in 7 healthy male ...subjects. Subjects received oral doses of 480 mg faldaprevir on day 1, followed by 240 mg faldaprevir on days 2 to 8 and 10 to 15. 14Cfaldaprevir (240 mg containing 100 μCi) was administered on day 9. Blood, urine, feces, and saliva samples were collected at intervals throughout the study. Metabolite profiling was performed using radiochromatography, and metabolite identification was conducted using liquid chromatography-tandem mass spectrometry. The overall recovery of radioactivity was high (98.8%), with the majority recovered from feces (98.7%). There was minimal radioactivity in urine (0.113%) and saliva. Circulating radioactivity was predominantly confined to plasma with minimal partitioning into red blood cells. The terminal half-life of radioactivity in plasma was approximately 23 h with no evidence of any long-lasting metabolites. Faldaprevir was the predominant circulating form, accounting for 98 to 100% of plasma radioactivity from each subject. Faldaprevir was the only drug-related component detected in urine. Faldaprevir was also the major drug-related component in feces, representing 49.8% of the radioactive dose. The majority of the remainder of radioactivity in feces (41% of the dose) was accounted for in almost equal quantities by 2 hydroxylated metabolites. The most common adverse events were nausea, diarrhea, and constipation, all of which were related to study drug. In conclusion, faldaprevir is predominantly excreted in feces with negligible urinary excretion.
Hypertension is a major risk factor for cardiovascular disease, a leading cause of premature death and disability in India. Since access to health services is poor in rural India and Accredited ...Social Health Activists (ASHAs) are available throughout India for maternal and child health, a potential solution for improving hypertension control is by utilising this available workforce. We aimed to develop and implement a training package for ASHAs to identify and control hypertension in the community, and evaluate the effectiveness of the training program using the Kirkpatrick Evaluation Model.
The training program was part of a cluster randomised feasibility trial of a 3-month intervention to improve hypertension outcomes in South India. Training materials incorporated details on managing hypertension, goal setting, facilitating group meetings, and how to measure blood pressure and weight. The 15 ASHAs attended a five-day training workshop that was delivered using interactive instructional strategies. ASHAs then led community-based education support groups for 3 months. Training was evaluated using Kirkpatrick's evaluation model for measuring reactions, learning, behaviour and results using tests on knowledge at baseline, post-training and post-intervention, observation of performance during meetings and post-intervention interviews.
The ASHAs' knowledge of hypertension improved from a mean score of 64% at baseline to 76% post-training and 84% after the 3-month intervention. Research officers, who observed the community meetings, reported that ASHAs delivered the self-management content effectively without additional assistance. The ASHAs reported that the training materials were easy to understand and useful in educating community members.
ASHAs can be trained to lead community-based group educational discussions and support individuals for the management of high blood pressure.
The feasibility trial is registered with the Clinical Trials Registry - India (CTRI) CTRI/2016/02/006678 (25/02/2016).
While targeted therapy against HER2 is an effective first-line treatment in HER2
breast cancer, acquired resistance remains a clinical challenge. The pseudokinase HER3, heterodimerisation partner of ...HER2, is widely implicated in the resistance to HER2-mediated therapy. Here, we show that lapatinib, an ATP-competitive inhibitor of HER2, is able to induce proliferation cooperatively with the HER3 ligand neuregulin. This counterintuitive synergy between inhibitor and growth factor depends on their ability to promote atypical HER2-HER3 heterodimerisation. By stabilising a particular HER2 conformer, lapatinib drives HER2-HER3 kinase domain heterocomplex formation. This dimer exists in a head-to-head orientation distinct from the canonical asymmetric active dimer. The associated clustering observed for these dimers predisposes to neuregulin responses, affording a proliferative outcome. Our findings provide mechanistic insights into the liabilities involved in targeting kinases with ATP-competitive inhibitors and highlight the complex role of protein conformation in acquired resistance.
P110α is a member of the phosphoinositide 3-kinase (PI3K) enzyme family that functions downstream of RAS. RAS proteins contribute to the activation of p110α by interacting directly with its RAS ...binding domain (RBD), resulting in the promotion of many cellular functions such as cell growth, proliferation and survival. Previous work from our lab has highlighted the importance of the p110α/RAS interaction in tumour initiation and growth. Here we report the discovery and characterisation of a cyclic peptide inhibitor (cyclo-CRVLIR) that interacts with the p110α-RBD and blocks its interaction with KRAS. cyclo-CRVLIR was discovered by screening a "split-intein cyclisation of peptides and proteins" (SICLOPPS) cyclic peptide library. The primary cyclic peptide hit from the screen initially showed a weak affinity for the p110α-RBD (K
about 360 µM). However, two rounds of amino acid substitution led to cyclo-CRVLIR, with an improved affinity for p110α-RBD in the low µM (K
3 µM). We show that cyclo-CRVLIR binds selectively to the p110α-RBD but not to KRAS or the structurally-related RAF-RBD. Further, using biophysical, biochemical and cellular assays, we show that cyclo-CRVLIR effectively blocks the p110α/KRAS interaction in a dose dependent manner and reduces phospho-AKT levels in several oncogenic KRAS cell lines.
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