A series of 3-oxo-C12-HSL, tetramic acid, and tetronic acid analogues were synthesized to gain insights into the structural requirements for quorum sensing inhibition in Staphylococcus aureus. Compounds active against agr were noncompetitive inhibitors of the autoinducing peptide (AIP) activated AgrC receptor, by altering the activation efficacy of the cognate AIP-1. They appeared to act as negative allosteric modulators and are exemplified by 3-tetradecanoyltetronic acid 17, which reduced nasal cell colonization and arthritis in a murine infection model.

In eukaryotic cells, the shortening and removal of the poly(A) tail of cytoplasmic mRNA by deadenylase enzymes is a critical step in post-transcriptional gene regulation. The ribonuclease activity of deadenylase enzymes is attributed to either a DEDD (Asp-Glu-Asp-Asp) or an endonuclease–exonuclease–phosphatase domain. Both domains require the presence of two Mg2+ ions in the active site. To facilitate the biochemical analysis of deadenylase enzymes, we have developed a fluorescence-based deadenylase assay. The assay is based on end-point measurement, suitable for quantitative analysis and can be adapted for 96- and 384-well microplate formats. We demonstrate the utility of the assay by screening a chemical compound library, resulting in the identification of non-nucleoside inhibitors of the Caf1/CNOT7 enzyme, a catalytic subunit of the Ccr4–Not deadenylase complex. These compounds may be useful tools for the biochemical analysis of the Caf1/CNOT7 deadenylase subunit of the Ccr4–Not complex and indicate the feasibility of developing selective inhibitors of deadenylase enzymes using the fluorescence-based assay.

The Pseudomonas aeruginosa quorum-sensing molecule N-(3-oxododecanoyl)-l-homoserine lactone (1) is involved not only in bacterial activation but also in subversion of the host immune system, and this compound might thus be used as a template to design immunosuppressive agents, provided derivatives devoid of quorum-sensing activity could be discovered. By use of a leukocyte proliferation assay and a newly developed bioluminescent P. aeruginosa reporter assay, systematic modification of 1 allowed us to delineate the bacterial LasR-induction and host immunosuppressive activities. The main determinant is replacement of the methylene group proximal to the β-ketoamide in the acyl chain of 1 with functions containing heteroatoms, especially an NH group. This modification can be combined with replacement of the homoserine lactone system in 1 with stable cyclic groups. For example, we found the simple compound N(1)-(5-chloro-2-hydroxyphenyl)-N(3)-octylmalonamide (25d) to be over twice as potent as 1 as an immune suppressor while displaying LasR-induction antagonist activity.

β-Blockers reduce mortality and improve symptoms in people with heart disease; however, current clinically available β-blockers have poor selectivity for the cardiac β1-adrenoceptor (AR) over the lung β2-AR. Unwanted β2-blockade risks causing life-threatening bronchospasm and reduced efficacy of β2-agonist emergency rescue therapy. Thus, current life-prolonging β-blockers are contraindicated in patients with both heart disease and asthma. Here, we describe NDD-713 and -825, novel highly β1-selective neutral antagonists with good pharmaceutical properties that can potentially overcome this limitation. Radioligand binding studies and functional assays that use human receptors expressed in Chinese hamster ovary cells demonstrate that NDD-713 and -825 have nanomolar β1-AR affinity >500-fold β1-AR vs. β2-AR selectivity and no agonism. Studies in conscious rats demonstrate that these antagonists are orally bioavailable and cause pronounced β1-mediated reduction of heart rate while showing no effect on β2-mediated hindquarters vasodilatation. These compounds also have good disposition properties and show no adverse toxicologic effects. They potentially offer a truly cardioselective β-blocker therapy for the large number of patients with heart and respiratory or peripheral vascular comorbidities.—Baker, J. G., Gardiner, S. M., Woolard, J., Fromont, C., Jadhav, G. P., Mistry, S. N., Thompson, K. S. J., Kellam, B., Hill, S. J., Fischer, P. M. Novel selective β1-adrenoceptor antagonists for concomitant cardiovascular and respiratory disease.

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