Cardiac Troponin Activator Increases Cardiac Contractility in Rats.

Novel cardiac troponin activators were identified using a high throughput cardiac myofibril ATPase assay and confirmed using a series of biochemical and biophysical assays. HTS hit increased rat cardiomyocyte fractional shortening without increasing intracellular calcium concentrations, and the biological target of and was determined to be the cardiac thin filament. Subsequent optimization to increase solubility and remove PDE-3 inhibition led to the discovery of and enabled pharmacological evaluation of cardiac troponin activation without the competing effects of PDE-3 inhibition.

Evaluation of amide replacements in CCR5 antagonists as a means to increase intrinsic permeability. Part 2: SAR optimization and pharmacokinetic profile of a homologous azacyle series.

Replacement of a secondary amide with a piperidine or azetidine moiety in a series of CCR5 antagonists led to the discovery of compounds with increased intrinsic permeability. This effort led to the identification of a potent CCR5 antagonist which exhibited an improved in vivo pharmacokinetic profile.

Exploration of a new series of CCR5 antagonists: multi-dimensional optimization of a sub-series containing N-substituted pyrazoles.

The introduction of N-substituted pyrazoles in a new series of CCR5 antagonists was shown to substantially increase antiviral activity.

Synthesis, SAR and evaluation of [1,4']-bipiperidinyl-4-yl-imidazolidin-2-one derivatives as novel CCR5 antagonists.

Elaboration of our previously disclosed spiropiperidine template led to the development of a series of novel CCR5 antagonists. Results of SAR exploration and preliminary lead characterization are described.

Novel hexahydropyrrolo[3,4-c]pyrrole CCR5 antagonists.

Starting with a high-throughput screening lead, a novel series of CCR5 antagonists was developed utilizing an information-based approach. Improvement of pharmacokinetic properties for the series was pursued by SAR exploration of the lead template. The synthesis, SAR and biological profiles of the series are described.

Evaluation of a 4-aminopiperidine replacement in several series of CCR5 antagonists.

The bicyclic 5-amino-3-azabicyclo[3.3.0]octanes were shown to be effective replacements for the conformationally restricted 4-aminopiperidine ring found in several series of CCR5 antagonists.

Evaluation of a 3-amino-8-azabicyclo[3.2.1]octane replacement in the CCR5 antagonist maraviroc.

The bicyclic 5-amino-3-azabicyclo[3.3.0]octanes were shown to be effective replacements for the 3-amino-8-azabicyclo[3.

Evaluation of secondary amide replacements in a series of CCR5 antagonists as a means to increase intrinsic membrane permeability. Part 1: Optimization of gem-disubstituted azacycles.

Replacement of a secondary amide with an N-acyl or N-sulfonyl gem-disubstituted azacyle in a series of CCR5 antagonists led to the identification of compounds with excellent in vitro HIV antiviral activity and increased intrinsic membrane permeability.

Spiropiperidine CCR5 antagonists.

A novel series of CCR5 antagonists has been identified, utilizing leads from high-throughput screening which were further modified based on insights from competitor molecules. Lead optimization was pursued by balancing opposing trends of metabolic stability and potency. Selective and potent analogs with good pharmacokinetic properties were successfully developed.

Discovery of a potent, selective and orally bioavailable 3,9-diazaspiro[5.5]undeca-2-one CCR5 antagonist.

Replacement of the cyclic carbamate in our previously disclosed 1-oxa-3,9-diazaspiro[5.5]undecan-2-one template led to the discovery of two novel series of 3,9-diazaspiro[5.5]undecane and undeca-2-one CCR5 antagonists.

CCR5 small-molecule antagonists and monoclonal antibodies exert potent synergistic antiviral effects by cobinding to the receptor.

A panel of four CCR5 monoclonal antibodies (mAbs) recognizing different epitopes on CCR5 was examined in CCR5-mediated cell-cell fusion assay, alone or in combination with a variety of small molecule CCR5 antagonists. Although no antagonism was observed between any of the CCR5 inhibitors, surprisingly potent synergy was observed between CCR5 mAbs and antagonists, and the synergistic activity was confirmed in other antiviral assays. Strong synergy was also observed between CCR5 inhibitors and the human immunodeficiency virus (HIV) fusion inhibitor enfuvirtide.

The second extracellular loop of CCR5 contains the dominant epitopes for highly potent anti-human immunodeficiency virus monoclonal antibodies.

Six mouse anti-human CCR5 monoclonal antibodies (mAbs) that showed potent antiviral activities were identified from over 26,000 mouse hybridomas. The epitopes for these mAbs were determined by using various CCR5 mutants, including CCR5/CCR2B chimeras. One mAb, ROAb13, was found to bind to a linear epitope in the N terminus of CCR5.

Two-metal ion mechanism of RNA cleavage by HIV RNase H and mechanism-based design of selective HIV RNase H inhibitors.

Human immunodeficiency virus (HIV) RNase H activity is essential for the synthesis of viral DNA by HIV reverse transcriptase (HIV-RT). RNA cleavage by RNase H requires the presence of divalent metal ions, but the role of metal ions in the mechanism of RNA cleavage has not been resolved. We measured HIV RNase H activity associated with HIV-RT protein in the presence of different concentrations of either Mg2+, Mn2+, Co2+ or a combination of these divalent metal ions.