The protozoan protein kinase calcium-dependent protein kinase 1 (CDPK1) has emerged as a potential therapeutic target for the treatment of cryptosporidiosis. A focused screen of known kinase inhibitors identified a pyridopyrimidinone as a new chemotype of Cryptosporidium parvum (Cp) CDPK1 inhibitors. Structural comparison of CpCDPK1 to two representative human kinases, RIPK2 and Src, revealed differences in the positioning of the alpha C-helix that was used in the design of a potent pyridopyrimidinone-based CpCDPK1 inhibitor 7 (a.k.a. UH15-16, IC50 = 10 nM), which blocked the growth of three C. parvum strains (EC50 = 12-40 nM) as well as C. hominis (EC50 = 85 nM) in HCT-8 host cells. Pharmacokinetic and tissue distribution analyses indicated that 7 had low systemic exposure after oral administration, but high gastrointestinal concentration, as well as good Caco-2 cell permeability. Finally, 7 demonstrated partial efficacy in an IL-12 knock-out mouse model of acute cryptosporidiosis.

Severe influenza A virus (IAV) infections can result in hyper-inflammation, lung injury and acute respiratory distress syndrome1-5 (ARDS), for which there are no effective pharmacological therapies. Necroptosis is an attractive entry point for therapeutic intervention in ARDS and related inflammatory conditions because it drives pathogenic lung inflammation and lethality during severe IAV infection6-8 and can potentially be targeted by receptor interacting protein kinase 3 (RIPK3) inhibitors. Here we show that a newly developed RIPK3 inhibitor, UH15-38, potently and selectively blocked IAV-triggered necroptosis in alveolar epithelial cells in vivo. UH15-38 ameliorated lung inflammation and prevented mortality following infection with laboratory-adapted and pandemic strains of IAV, without compromising antiviral adaptive immune responses or impeding viral clearance. UH15-38 displayed robust therapeutic efficacy even when administered late in the course of infection, suggesting that RIPK3 blockade may provide clinical benefit in patients with IAV-driven ARDS and other hyper-inflammatory pathologies.

Receptor interacting protein kinase-2 (RIPK2) is an enzyme involved in the transduction of pro-inflammatory nucleotide-binding oligomerization domain (NOD) cell signaling, a pathway implicated in numerous chronic inflammatory conditions. Herein, a pyrido[2,3-d]pyrimidin-7-one based class of RIPK2 kinase and NOD2 cell signaling inhibitors is described. For example, 33 (e.g. UH15-15) inhibited RIPK2 kinase (IC50 = 8 +/- 4 nM) and displayed > 300-fold selectivity versus structurally related activin receptor-like kinase 2 (ALK2). This molecule blocked NOD2-dependent HEKBlue NF-kappa B activation (IC50 = 20 +/- 5 nM) and CXCL8 production (at concentrations > 10 nM). Molecular docking suggests that engagement of Ser25 in the glycine-rich loop may provide increased selectivity versus ALK2 and optimal occupancy of the region between the gatekeeper and the alpha C-helix may contribute to potent NOD2 cell signaling inhibition. Finally, this compound also demonstrated favorable in vitro ADME and pharmacokinetic properties (e.g. C-max = 5.7 mu M, T-max = 15 min, t(1/ 2) = 3.4 h and Cl = 45 mL/min/kg following single 10 mg/kg intraperitoneal administration) further supporting the use of pyrido[2,3-d]pyrimidin-7-ones as a new structure class of RIPK2 kinase and NOD cell signaling inhibitors. (C) 2021 Elsevier Masson SAS. All rights reserved.

Gene ID / UniProt ID / EC 8767 / O43353 / Target Nominator SGC Internal Nomination SGC Authors Peter Canning, Daniel M. Pinkas, Joshua C. Bufton, Sarah Picaud, Jennifer A. Ward, Catherine Rogers, Benedict-Tilman Berger, Stefan Knapp, Susanne Muller-Knapp, Paul E. Brennan, Kilian V. M. Huber, Panagis Filippakopoulos, Alex N. Bullock Collaborating Authors Matous Hrdinka, Qui Ruan, Chalada Suebsuwong, Lisa Schlicher, Bing Dai, Jenny L. Maki, Soumya S. Ray, Danish Saleh, Sameer Nikhar, Tobias Schwerd, Holm H.Uhlig, Gregory D. Cuny, Alexei Degterev, Mads Gyrd-Hansen Target PI Alex N. Bullock (SGC Oxford) Therapeutic Area(s) Inflammatory diseases Disease Relevance Mutations in the NOD2-RIPK2 pathway identify RIPK2 a potential therapeutic target in auto-immune and inflammatory conditions such as Crohn’s disease, Blau syndrome, early-onset osteoarthritis and multiple sclerosis. Date Approved by TEP Evaluation Group 13 June 2018

The treatment of tumors driven by overexpression or amplification of MYC oncogenes remains a significant challenge in drug discovery. Here, we present a new strategy toward the inhibition of MYC via the disruption of the protein-protein interaction between MYC and its chromatin cofactor WD Repeat-Containing Protein 5. Blocking the association of these proteins is hypothesized to disrupt the localization of MYC to chromatin, thus disrupting the ability of MYC to sustain tumorigenesis. Utilizing a high-throughput screening campaign and subsequent structure-guided design, we identify small-molecule inhibitors of this interaction with potent in vitro binding affinity and report structurally related negative controls that can be used to study the effect of this disruption. Our work suggests that disruption of this protein-protein interaction may provide a path toward an effective approach for the treatment of multiple tumors and anticipate that the molecules disclosed can be used as starting points for future efforts toward compounds with improved drug-like properties.

The treatment of tumors driven by overexpression or amplification of MYC oncogenes remains a significant challenge in drug discovery. Here, we present a new strategy towards the inhibition of MYC via the disruption of the protein-protein-interaction between MYC and its chromatin cofactor WDR5. Blocking the association of these proteins is hypothesized to disrupt the localization of MYC to chromatin, thus disrupting the ability of MYC to sustain tumorigenesis. Utilizing a high-throughput screening campaign and subsequent structure-guided design, we identify small molecule inhibitors of this interaction with potent in vitro binding affinity, and report structurally related negative controls that can be used to study the effect of this disruption. Our work suggests that disruption of this protein-protein interaction may provide a path toward an effective approach for the treatment of multiple tumors, and anticipate that the molecules disclosed can be used as starting points for future efforts toward compounds with improved drug-like properties.

RIPK2 mediates inflammatory signaling by the bacteria‐sensing receptors NOD1 and NOD2. Kinase inhibitors targeting RIPK2 are a proposed strategy to ameliorate NOD‐mediated pathologies. Here, we reveal that RIPK2 kinase activity is dispensable for NOD2 inflammatory signaling and show that RIPK2 inhibitors function instead by antagonizing XIAP‐binding and XIAP‐mediated ubiquitination of RIPK2. We map the XIAP binding site on RIPK2 to the loop between β2 and β3 of the N‐lobe of the kinase, which is in close proximity to the ATP‐binding pocket. Through characterization of a new series of ATP pocket‐binding RIPK2 inhibitors, we identify the molecular features that determine their inhibition of both the RIPK2‐XIAP interaction, and of cellular and in vivoNOD2 signaling. Our study exemplifies how targeting of the ATP‐binding pocket in RIPK2 can be exploited to interfere with the RIPK2‐XIAP interaction for modulation of NOD signaling. Bacteria‐sensing NOD receptors promote inflammatory signalling by stimulating XIAP‐dependent RIPK2 ubiquitination. New RIPK2 kinase inhibitors act by blocking RIPK2‐XIAP binding, thus revealing a strategy to impair NOD signalling independently of RIPK2 kinase activity. A new class of RIPK2 inhibitors dampen inflammatory signalling in a kinase‐independent manner by blocking RIPK2‐XIAP binding and RIPK2 ubiquitination.

Key residues and binding mechanisms of PGE1 and PGE2 on prostanoid receptors are poorly understood due to the lack of X-ray structures for the receptors. We constructed a human EP3 (hEP3) model through integrative homology modeling using the X-ray structure of the β2-adrenergic receptor transmembrane domain and NMR structures of the thromboxane A2 receptor extracellular loops. PGE1 and PGE2 docking into the hEP3 model showed differing configurations within the extracellular ligand recognition site. While PGE2 could form possible binding contact with S211, PGE1 is unable to form similar contacts. Therefore, S211 could be the critical residue for PGE2 recognition, but is not a significant for PGE1. This prediction was confirmed using HEK293 cells transfected with hEP3 S211L cDNA. The S211L cells lost PGE2 binding and signaling. Interestingly, the S211L cells retained PGE1-mediated signaling. It indicates that S211 within the second extracellular loop is a key residue involved in turning down PGE2 signaling. Our study provided information that S211L within EP3 is the key residue to distinguish PGE1 and PGE2 binding to mediate diverse biological functions at the initial recognition step. The S211L mutant could be used as a model for studying the binding mechanism and signaling pathway specifically mediated by PGE1.

A synthesis of gombamide A (1) using N-terminal peptide extension, oxidative disulfide bond formation, and late-stage 4-hydroxystyrylamide installation has been achieved. This divergent method was also utilized to synthesize several gombamide A derivatives with modification to the 4-hydroxystyrylamide via cyclic peptide 2. The natural product and four derivatives were found to be devoid of Na(+)/K(+)-ATPase activity at 10 μM. In addition, the compounds were not cytotoxic at 10 μM against a panel of cancer cells.

Cancer continues to be one of the biggest threats to the human civilization because there is no cure of it. Small heterocyclic molecule with low molecular weight and novel structural feature is therapeutically highly demanding. These molecules have the capability to disrupt signaling pathways leading to anticancer activities. Therefore, the search for new anticancer agents continues to draw attention to the research community. In this study, a small triazolo‐benzoxazepine scaffolds was synthesized using a one‐pot four‐step synthetic methodology involving click reaction. Small libraries of 12 compounds were successfully synthesized and screened them against different cancer cell lines. Low micromolar anticancer activity was recorded using MTT assay, and further confirmation of cell death was obtained by phase contrast, fluorescent, and confocal images.