Publications by authors named "Peet G"

Unlabelled: KRAS inhibitors have demonstrated exciting preclinical and clinical responses, although resistance occurs rapidly. Here, we investigate the effects of KRAS-targeting therapies on the tumor microenvironment using a library of KrasG12D, p53-mutant, murine pancreatic ductal adenocarcinoma-derived cell lines (KPCY) to leverage immune-oncology combination strategies for long-term tumor efficacy. Our findings show that SOS1 and MEK inhibitors (SOS1i+MEKi) suppressed tumor growth in syngeneic models and increased intratumoral CD8+ T cells without durable responses.

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Hematopoietic stem cell transplantation (HSCT) can replace endogenous microglia with circulation-derived macrophages but has high mortality. To mitigate the risks of HSCT and expand the potential for microglia replacement, we engineered an inhibitor-resistant CSF1R that enables robust microglia replacement. A glycine to alanine substitution at position 795 of human CSF1R (G795A) confers resistance to multiple CSF1R inhibitors, including PLX3397 and PLX5622.

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We present a high-resolution miniature, light-weight fluorescence microscope with electrowetting lens and onboard CMOS for high resolution volumetric imaging and structured illumination for rejection of out-of-focus and scattered light. The miniature microscope (SIMscope3D) delivers structured light using a coherent fiber bundle to obtain optical sectioning with an axial resolution of 18 µm. Volumetric imaging of eGFP labeled cells in fixed mouse brain tissue at depths up to 260 µm is demonstrated.

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Microglia, the brain's tissue-resident macrophages, contribute to the developmental elimination of extranumerary synapses and to pathologic synapse loss in mouse models of neurodegeneration. Two papers published in The EMBO Journal reveal that phosphatidylserine (PS) is a neuronal cue for microglial synapse elimination.

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The immune microenvironment of hepatocellular carcinoma (HCC) is poorly characterized. Combining two single-cell RNA sequencing technologies, we produced transcriptomes of CD45 immune cells for HCC patients from five immune-relevant sites: tumor, adjacent liver, hepatic lymph node (LN), blood, and ascites. A cluster of LAMP3 dendritic cells (DCs) appeared to be the mature form of conventional DCs and possessed the potential to migrate from tumors to LNs.

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Vascular adhesion protein-1 (VAP-1) has been implicated in the pathogenesis of inflammatory diseases and is suggested to play a role in immune cell trafficking. It is not clear whether this effect is mediated by the oxidase activity or by other features of the protein such as direct adhesion. In order to study the role of VAP-1 oxidase activity in vivo, we have generated mice carrying an oxidase activity-null VAP-1 protein.

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Vascular adhesion protein-1 (VAP-1), also known as semicarbazide-sensitive amine oxidase (SSAO) or copper-containing amine oxidase (AOC3, EC 1.4.3.

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An SAR study that identified a series of thienopyridine-based potent IkappaB Kinase beta (IKKbeta) inhibitors is described. With focuses on the structural optimization at C4 and C6 of structure 1 (Fig. 1), the study reveals that small alkyl and certain aromatic groups are preferred at C4, whereas polar groups with proper orientation at C6 efficiently enhance compound potency.

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The characterization of the potent p38 inhibitor BIRB796 as a dual inhibitor of p38/Jun N-terminal kinases (JNK) mitogen-activated protein kinases (EC 2.7.11.

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The discovery of a series of potent, carboline-based MK2 inhibitors is described. These compounds inhibit MK2 with IC50s as low as 10 nM, as measured in a DELFIA assay. An X-ray crystal structure reveals that they bind in a region near the p-loop and the hinge region of MK2a.

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A novel inhibitor of p38 mitogen-activated protein kinase (p38), CMPD1, identified by high-throughput screening, is characterized herein. Unlike the p38 inhibitors described previously, this inhibitor is substrate selective and noncompetitive with ATP. In steady-state kinetics experiments, CMPD1 was observed to prevent the p38alpha-dependent phosphorylation (K(i)(app) = 330 nM) of the splice variant of mitogen-activated protein kinase-activated protein kinase 2 (MK2a) that contains a docking domain for p38alpha and p38beta, but it did not prevent the phosphorylation of ATF-2 (K(i)(app) > 20 microM).

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The p38 mitogen-activated protein kinase (p38) pathway is required for the production of proinflammatory cytokines (TNFalpha and IL-1) that mediate the chronic inflammatory phases of several autoimmune diseases. Potent p38 inhibitors, such as the slow tight-binding inhibitor BIRB 796, have recently been reported to block the production of TNFalpha and IL-1beta. Here we analyze downstream signaling complexes and molecular mechanisms, to provide new insight into the function of p38 signaling complexes and the development of novel inhibitors of the p38 pathway.

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It has been reported that the diaryl urea class of p38alpha inhibitors binds to p38 map kinase with both high affinity and slow binding kinetics (Pargellis et al. Nat. Struct.

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BIRB 796, a member of the N-pyrazole-N'-naphthly urea class of p38MAPK inhibitors, binds to the kinase with both slow association and dissociation rates. Prior to binding, the kinase undergoes a reorganization of the activation loop exposing a critical binding domain. We demonstrate that, independent of the loop movement, association rates are governed by low energy conformations of the inhibitor and polar functionality on the tolyl ring.

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The tyrosine kinase p56lck (lck) is essential for T cell activation; thus, inhibitors of lck have potential utility as autoimmune agents. Our initial disclosure of a new class of lck inhibitors based on the phenylaminoimidazoisoquinolin-9-one showed reasonable cellular activity but did not work in vivo upon oral administration. Our current work highlights the further use of rational drug design and molecular modeling to produce a series of lck inhibitors that demonstrate cellular activity below 100 nM and are as efficacious as cyclosporin A in an in vivo mouse model of anti-CD3-induced IL-2 production.

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The IKKbeta and NEMO/IKKgamma subunits of the NF-kappaB-activating signalsome complex are known to be essential for activating NF-kappaB by inflammatory and other stress-like stimuli. However, the IKKalpha subunit is believed to be dispensable for the latter responses and instead functions as an in vivo mediator of other novel NF-kappaB-dependent and -independent functions. In contrast to this generally accepted view of IKKalpha's physiological functions, we demonstrate in mouse embryonic fibroblasts (MEFs) that, akin to IKKbeta and NEMO/IKKgamma, IKKalpha is also a global regulator of tumor necrosis factor alpha- and IL-1-responsive IKK signalsome-dependent target genes including many known NF-kappaB targets such as serum amyloid A3, C3, interleukin (IL)-6, IL-11, IL-1 receptor antagonist, vascular endothelial growth factor, Ptx3, beta(2)-microglobulin, IL-1alpha, Mcp-1 and -3, RANTES (regulated on activation normal T cell expressed and secreted), Fas antigen, Jun-B, c-Fos, macrophage colony-stimulating factor, and granulocyte-macrophage colony-stimulating factor.

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An imidazo[4,5-h]isoquinolin-7,9-dione (1) was identified as an adenosine 5'-triphosphate competitive inhibitor of lck by high throughput screening. Initial structure-activity relationship studies identified the dichlorophenyl ring and the imide NH as important pharmacophores. A binding model was constructed to understand how 1 binds to a related kinase, hck.

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The IkappaB kinase (IKK) signaling complex is responsible for activating NF-kappaB-dependent gene expression programs. Even though NF-kappaB-responsive genes are known to orchestrate stress-like responses, critical gaps in our knowledge remain about the global effects of NF-kappaB activation on cellular physiology. DNA microarrays were used to compare gene expression programs in a model system of 70Z/3 murine pre-B cells versus their IKK signaling-defective 1.

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Background: Effective pain management after removal of femoral artery sheaths after percutaneous transluminal coronary angioplasty is highly individualized and requires frequent, accurate assessment and administration of analgesics as needed.

Objective: To determine which of 3 analgesic regimens is most effective in decreasing patients' perception of pain with the fewest side effects after removal of a femoral artery sheath.

Sample: 130 adult who had undergone percutaneous transluminal coronary angioplasty and were in an 8-bed cardiac short-stay unit in a 1400-bed acute care hospital.

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Activation of transcription factor NF-kappaB is regulated by phosphorylation and subsequent degradation of its inhibitory subunit IkappaB. The signal-induced phosphorylation of IkappaB involves two IkappaB kinases, IKKalpha and IKKbeta. In the present study, we investigated the kinetic mechanisms of IKKalpha and IKKbeta by substrate and product inhibition.

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Activation of the transcription factor NF-kappaB is regulated by the phosphorylation and subsequent degradation of its inhibitory subunit, IkappaB. A large multiprotein complex, the IkappaB kinase (IKK), catalyzes the phosphorylation of IkappaB. The two kinase components of the IKK complex, IKKalpha and IKKbeta, were overexpressed in insect cells and purified to homogeneity.

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An N1 strain of influenza A virus neuraminidase (A/WSN/33 NA) was purified and used to screen for inhibitors. As a result, a well-known tuberculostatic, 4'-formylacetanilide thiosemicarbazone (or thiacetazone), was identified. Thiacetazone is a non-sialate compound and inhibits the enzyme in a noncompetitive manner with respect to the substrate sialic acid.

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A cross-sectional survey was conducted to examine current Canadian practices in the nursing and medical management of femoral arterial sheath removal (SR) after PTCA (percutaneous transluminal coronary angioplasty). The purposes of the study were to (a) investigate the roles of the nurses and physicians in SR, (b) assess the length of time arterial sheaths are left in place and patients kept on bedrest, and (c) describe the routine medical protocols used for pain and anticoagulation therapy. Of the 35 hospitals that perform PTCA in Canada, 30 responded to the survey (response rate of 86%).

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Background: We investigated differences in the value of clinical information communicated between referring physicians and consulting physicians in the setting of shared care of patients who had chronic problems.

Method: An 18-item questionnaire included items that measure the value of information received from the other physician, referring and consulting physician roles, preference for method of communication, and content of communication. Questionnaires were mailed to a study sample consisting of 200 referring family physicians and 200 consulting specialists.

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Background: Medical treatment of the elderly is changing to include the aggressive management of coronary artery disease with percutaneous transluminal coronary angioplasty.

Objective: The purpose of this study was to review major hospital events of patients aged 70 years or more, who underwent a first percutaneous transluminal coronary angioplasty.

Methods: A retrospective medical record review was done of 246 consecutive patients of 70 years or more, from January 1985 to December 1988, at a tertiary care community hospital.

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