John August Wos

Effects of β3-Adrenergic Receptor Activation on Rat Urinary Bladder Hyperactivity Induced by Ovariectomy

Voiding dysfunctions, including increased voiding frequency, urgency, or incontinence, are prevalent in the postmenopausal population. β3-Adrenergic receptor (β3AR) agonists, which relax bladder smooth muscle, are being developed to treat these conditions. We utilized the rat ovariectomy (OVX) model to investigate the effect of ovarian hormone depletion on bladder function and the potential for β3AR agonists to treat bladder hyperactivity in this setting. OVX increased voiding frequency and decreased bladder capacity by ∼25% in awake rats and induced irregular cystometrograms in urethane-anesthetized rats. Reverse transcription-polymerase chain reaction revealed three βARs subtypes (β1,2,3) in bladder tissue, and immunostaining indicated β3AR localization in urothelium and detrusor. Receptor expression was not different in OVX and SHAM rats. The β3AR agonist selectivity of BRL37344 [(±)-(R*,R*)-[4-[2-[[2-(3-chlorophenyl)-2-hydroxyethyl]amino]propyl]phenoxy]acetic acid sodium hydrate], TAK-677 [(3-((2R)-(((2R)-(3-chlorophenyl)-2-hydroxyethyl)amino)propyl)-1H-indol-7-yloxy)acetic acid], and FK175 [acetic acid, 2-[[(8S)-8-[[(2R)-2-(3-chlorophenyl)-2-hydroxyethyl]amino]-6,7,8,9-tetrahydro-5H-benzocyclohepten-2-yl]oxy], ethyl ester, hydrochloride] was confirmed by examining the relative potency for elevation of cAMP in CHOK1 cells overexpressing the various rat βARs. Intravenous injection of each of the β3AR agonists (0.1–500 μg/kg) in anesthetized rats decreased voiding frequency, bladder pressure, and amplitude of bladder contractions. In bladder strips, β3AR agonists (10-12-10-4 M) decreased baseline tone and reduced spontaneous contractions. BRL37344 (5 mg/kg) and TAK-677 (5 mg/kg) injected intraperitoneally in awake rats decreased voiding frequency by 40 to 70%. These effects were not altered by OVX. The results indicate that OVX-induced bladder dysfunction, including decreased bladder capacity and increased voiding frequency, is not associated with changes in β3AR expression or the bladder inhibitory effects of β3AR agonists. This suggests that β3AR agonists should prove effective for the treatment of overactive bladder symptoms in the postmenopausal population.

Discovery of orally bioavailable 1,3,4-trisubstituted 2-oxopiperazine-based melanocortin-4 receptor agonists as potential antiobesity agents.

A study that was designed to identify plausible replacements for highly basic guanidine moiety contained in potent MC4R agonists, as exemplified by 1, led to the discovery of initial nonguanidine lead 5. Propyl analog 23 was subsequently found to be equipotent to 5, whereas analogs bearing smaller and branched alkyl groups at the 3 position of the oxopiperazine template demonstrated reduced binding affinity and agonist potency for MC4R. Acylation of the NH2 group of the 4F-D-Phe residue of 3-propyl analog 23 significantly increased the binding affinity and the functional activity for MC4R. Analogs with neutral and weakly basic capping groups of the D-Phe residue exhibited excellent MC4R selectivity against MC1R whereas those with an amino acid had moderate MC4R/MC1R selectivity. We have also demonstrated that compound 35 showed promising oral bioavailability and a moderate oral half life and induced significant weight loss in a 28-day rat obesity model.

Small-molecule melanin-concentrating hormone-1 receptor antagonists require brain penetration for inhibition of food intake and reduction in body weight.

The melanin-concentrating hormone-1 receptor (MCH1R) is a G-protein-coupled receptor expressed in the brain and peripheral tissues that regulates energy storage and body weight. Here, we focused on discovery of the mechanism and site of action for a small-molecule MCH1R antagonist, which yields weight loss in a mouse model of human obesity. MCH1R is expressed throughout the brain but also found in peripheral tissues known to regulate fat storage and utilization, e.g., skeletal muscle and adipose tissue. Previous studies of MCH1R antagonist studies have not delineated the site that is critical for mediating the anorexigenic and weight-reducing actions. In this study, we evaluated the role of the brain and peripheral tissue receptors. We developed a novel nonbrain-permeable MCH antagonist analog with a carboxylic acid moiety to specifically test the site of action. Based on in vitro and in vivo assays, the analog is not able to cross the blood-brain barrier and does not lead to inhibition of food intake and reduced body weight. The data clearly demonstrate that MCH1R antagonists need access to the brain to reduce body weight and fat mass. The brain-permeable MCH1R antagonist leads to significant reduction in body weight and fat mass in diet-induced obese mice. The effect is dose-dependent and appears to be partially driven by a reduction in food intake. Finally, these studies show the utility of a medicinal chemistry approach to address an important biological and pharmacological question.

Synthesis and in vitro evaluation of human FP-receptor selective prostaglandin analogues

The in vitro evaluation of a series of saturated prostaglandins revealed that compounds with omega chain aromatic rings retain nanomolar potency for the human prostaglandin F receptor (hFP receptor), exemplified by compound 8. In contrast, the double bonds are required for activity in the series with an acyclic omega chain as in PGF2alpha.

Patent developments in anabolic agents for treatment of bone diseases

A review of the patent literature encompassing the past 3 years (~ 2000 – 2003) in the area of bone anabolic therapies for treatment of osteoporosis and related diseases is described. A variety of potential therapeutics are covered, as well as improvement attempts on the first approved bone anabolic agent, recombinant human parathyroid hormone (rPTH; teriparatide, Forteo®, Eli Lilly & Co.). The patent literature suggests that multiple strategies are currently being pursued in order to deliver the first orally bioavailable anabolic agent to the market and that a variety of new targets are also being evaluated for further development.

The Rational Design of Drugs with Phos-phonic/phinic Acids as Enzyme Inhibitors Isosteric Receptor Ligands

Phosphonic/phosphinic acid analogs have been studied for inhibitory and ligand activity in farnesyl pyrophosphate synthase, prostaglandin, and other GPCRs.