Necroptosis blockade prevents lung injury in severe influenza

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.

Discovery and Optimization of Salicylic Acid-Derived Sulfonamide Inhibitors of the WD Repeat-Containing Protein 5-MYC Protein-Protein Interaction

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.

Small molecule inhibitors reveal an indispensable scaffolding role of RIPK2 in NOD2 signaling

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.

The key residue within the second extracellular loop of human EP3 involved in selectively turning down PGE2- and retaining PGE1-mediated signaling in live cells

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.

Synthesis and cytotoxicity studies of novel triazolo-benzoxazepine as new anticancer agents

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.