Development of an Optical Nanosensor Incorporating a pH-Sensitive Quencher Dye for Potassium Imaging.

One of the key challenges in the design of a sensor for measuring extracellular changes in potassium concentration is selectivity against the competing cation, sodium. Here, we present an optode-based nanosensor selective to potassium ions, owing to the addition of a pH-sensitive quencher molecule paired with a static fluorophore. The nanosensor was fabricated using emulsification and characterized in solution by absorbance and fluorescence spectroscopy. The resulting nanosensor detected potassium with nearly 1 order of magnitude higher selectivity compared to our chromoionophore-based optode nanosensors. In addition to the improved selectivity, the nanosensor has the following properties required for measurements in a biological environment: (1) a physiologically relevant dynamic range, (2) response to potassium ions at a physiological ionic strength, and (3) response to serum potassium in the presence of fouling biological components. The potassium nanosensor described in this study is envisioned to have application in cellular imaging and drug screening.

Discovery of biaryl carboxylamides as potent RORγ inverse agonists.

RORγt is a pivotal regulator of a pro-inflammatory gene expression program implicated in the pathology of several major human immune-mediated diseases. Evidence from mouse models demonstrates that genetic or pharmacological inhibition of RORγ activity can block the production of pathogenic cytokines, including IL-17, and convey therapeutic benefit. We have identified and developed a biaryl-carboxylamide series of RORγ inverse agonists via a structure based design approach. Co-crystal structures of compounds 16 and 48 supported the design approach and confirmed the key interactions with RORγ protein; the hydrogen bonding with His479 was key to the significant improvement in inverse agonist effect. The results have shown this is a class of potent and selective RORγ inverse agonists, with demonstrated oral bioavailability in rodents.

Discovery of novel hepatoselective HMG-CoA reductase inhibitors for treating hypercholesterolemia: a bench-to-bedside case study on tissue selective drug distribution.

The design of drugs with selective tissue distribution can be an effective strategy for enhancing efficacy and safety, but understanding the translation of preclinical tissue distribution data to the clinic remains an important challenge. As part of a discovery program to identify next generation liver selective HMG-CoA reductase inhibitors we report the identification of (3R,5R)-7-(4-((3-fluorobenzyl)carbamoyl)-5-cyclopropyl-2-(4-fluorophenyl)-1H-imidazol-1-yl)-3,5-dihydroxyheptanoic acid (26) as a candidate for treating hypercholesterlemia. Clinical evaluation of 26 (PF-03491165), as well as the previously reported 2 (PF-03052334), provided an opportunity for a case study comparison of the preclinical and clinical pharmacokinetics as well as pharmacodynamics of tissue targeted HMG-CoA reductase inhibitors.

Thermodynamic and structure guided design of statin based inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase.

Clinical studies have demonstrated that statins, 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) inhibitors, are effective at lowering mortality levels associated with cardiovascular disease; however, 2-7% of patients may experience statin-induced myalgia that limits compliance with a treatment regimen. High resolution crystal structures, thermodynamic binding parameters, and biochemical data were used to design statin inhibitors with improved HMGR affinity and therapeutic index relative to statin-induced myalgia. These studies facilitated the identification of imidazole 1 as a potent (IC 50 = 7.9 nM) inhibitor with excellent hepatoselectivity (>1000-fold) and good in vivo efficacy. The binding of 1 to HMGR was found to be enthalpically driven with a Delta H of -17.7 kcal/M. Additionally, a second novel series of bicyclic pyrrole-based inhibitors was identified that induced order in a protein flap of HMGR. Similar ordering was detected in a substrate complex, but has not been reported in previous statin inhibitor complexes with HMGR.

Substituted pyrazoles as hepatoselective HMG-CoA reductase inhibitors: discovery of (3R,5R)-7-[2-(4-fluoro-phenyl)-4-isopropyl-5-(4-methyl-benzylcarbamoyl)-2H-pyrazol-3-yl]-3,5-dihydroxyheptanoic acid (PF-3052334) as a candidate for the treatment of hypercholesterolemia.

In light of accumulating evidence that aggressive LDL-lowering therapy may offer increased protection against coronary heart disease, we undertook the design and synthesis of a novel series of HMG-CoA reductase inhibitors based upon a substituted pyrazole template. Optimizing this series using both structure-based design and molecular property considerations afforded a class of highly efficacious and hepatoselective inhibitors resulting in the identification of (3 R,5 R)-7-[2-(4-fluoro-phenyl)-4-isopropyl-5-(4-methyl-benzylcarbamoyl)-2 H-pyrazol-3-yl]-3,5-dihydroxy-heptanoic (PF-3052334) as a candidate for the treatment of hypercholesterolemia.

Arylpiperazine substituted heterocycles as selective alpha(1a) adrenergic antagonists.

Antagonists of the alpha(1)-adrenergic receptors (alpha(1)-ARs) are useful for the treatment of benign prostatic hyperplasia. A series of potent and subtype-selective alpha(1a)-AR antagonists has been synthesized, displaying in vitro binding affinity in the low the nanomolar range.

Antiproliferative Hybrid Analogs of the Hormone 1alpha,25-Dihydroxyvitamin D(3): Design, Synthesis, and Preliminary Biological Evaluation.

The combination of 10-12 kbar pressure plus Lewis acidic zinc dichloride promotes highly regioselective and stereoselective Diels-Alder cycloaddition between 3-bromo-2-pyrone, prepared in a new way, and unactivated terminal alkene 4-(tert-butyldimethylsiloxy)-1-butene. The conjugate base of A-ring allylic phosphine oxide 20 adds chemospecifically to the C-8 keto group of some C-8,C-24-diketones to form directly metabolically resistant 24-oxo analogs of 1alpha,25-dihydroxyvitamin D(3) (calcitriol). Several of these new hybrid analogs are as efficacious in vitro as calcitriol at inhibiting growth of murine keratinocytes even at physiologically relevant 10-100 nanomolar concentrations.