Mary Struthers

Leukotriene B4 Strongly Increases Monocyte Chemoattractant Protein-1 in Human Monocytes

Objective—Leukotriene B4 (LTB4), a product of the 5-lipoxygenase (5-LO) pathway of arachidonic acid metabolism, has been implicated in atherosclerosis. However, the molecular mechanisms for the atherogenic effect of LTB4 are not well understood. This study is to determine candidate mechanisms. Method and Results—Primary human monocytes were treated with LTB4 and the supernatant was analyzed for cytokine/chemokine production by an immuno-protein array. This analysis revealed a strong increase of the monocyte chemoattractant protein-1 (MCP-1), a proinflammatory cytokine. Follow-up analyses with MCP-1 enzyme-linked immunosorbent assay (for quantitation of MCP-1 protein) and real-time polymerase chain reaction (PCR) (for MCP-1 mRNA) demonstrated that LTB4 strongly induced expression of MCP-1 protein and mRNA in a time-dependent and dose-dependent fashion. This induction was effectively abolished by CP-105,696, an antagonist for the LTB4 receptor BLT1. Selective inhibitors of ERK1/2 or JNK MAPK effectively blocked the LTB4-induced MCP-1 production. Furthermore, LTB4 increased NF-&kgr;B DNA binding activity, which was blocked by CP-105,696. Conclusions—LTB4 strongly induces MCP-1 production in primary human monocytes. This induction is mediated through the BLT1 pathway increasing MCP-1 transcription. Activation of ERK1/2 or JNK MAPK is essential for this induction. The NF-&kgr;B activation may be involved in LTB4-increased MCP-1 expression. The LTB4-induced MCP-1 in human monocytes may play a critical role in the atherogenicity of LTB4.

Design, synthesis, and structure-activity relationship of novel CCR2 antagonists.

A series of novel 1-aminocyclopentyl-3-carboxyamides incorporating substituted tetrahydropyran moieties have been synthesized and subsequently evaluated for their antagonistic activity against the human CCR2 receptor. Among them analog 59 was found to posses potent antagonistic activity.

Design, Synthesis, and Evaluation of Conformationally Restricted Acetanilides as Potent and Selective β3 Adrenergic Receptor Agonists for the Treatment of Overactive Bladder

A series of conformationally restricted acetanilides were synthesized and evaluated as β3-adrenergic receptor agonists (β3-AR) for the treatment of overactive bladder (OAB). Optimization studies identified a five-membered ring as the preferred conformational lock of the acetanilide. Further optimization of both the aromatic and thiazole regions led to compounds such as 19 and 29, which have a good balance of potency and selectivity. These compounds have significantly reduced intrinsic clearance compared to our initial series of pyridylethanolamine β3-AR agonists and thus have improved unbound drug exposures. Both analogues demonstrated dose dependent β3-AR mediated responses in a rat bladder hyperactivity model.

Discovery of Vibegron: A Potent and Selective β3 Adrenergic Receptor Agonist for the Treatment of Overactive Bladder.

The discovery of vibegron, a potent and selective human β3-AR agonist for the treatment of overactive bladder (OAB), is described. An early-generation clinical β3-AR agonist MK-0634 (3) exhibited efficacy in humans for the treatment of OAB, but development was discontinued due to unacceptable structure-based toxicity in preclinical species. Optimization of a series of second-generation pyrrolidine-derived β3-AR agonists included reducing the risk for phospholipidosis, the risk of formation of disproportionate human metabolites, and the risk of formation of high levels of circulating metabolites in preclinical species. These efforts resulted in the discovery of vibegron, which possesses improved druglike properties and an overall superior preclinical profile compared to MK-0634. Structure-activity relationships leading to the discovery of vibegron and a summary of its preclinical profile are described.

Potent heteroarylpiperidine and carboxyphenylpiperidine 1-alkyl-cyclopentane carboxamide CCR2 antagonists.

This report describes replacement of the 4-(4-fluorophenyl)piperidine moiety in our CCR2 antagonists with 4-heteroaryl piperidine and 4-(carboxyphenyl)-piperidine subunits. Some of the resulting analogs retained potency in our CCR2 binding assay and had improved selectivity versus the I(Kr) channel; poor selectivity against I(Kr) had been a liability of earlier analogs in this series.

Discovery of Benzimidazole CYP11B2 Inhibitors with in Vivo Activity in Rhesus Monkeys

We report the discovery of a benzimidazole series of CYP11B2 inhibitors. Hit-to-lead and lead optimization studies identified compounds such as 32, which displays potent CYP11B2 inhibition, high selectivity versus related CYP targets, and good pharmacokinetic properties in rat and rhesus. In a rhesus pharmacodynamic model, 32 produces dose-dependent aldosterone lowering efficacy, with no apparent effect on cortisol levels.

Dual targeting of CCR2 and CX3CR1 in an arterial injury model of vascular inflammation

ObjectivesThe chemokine receptors CCR2 and CX3CR1 are important in the development of coronary artery disease. The purpose of this study is to analyze the effect of a novel CCR2 inhibitor in conjunction with CX3CR1 deletion on vascular inflammation.MethodsThe novel CCR2 antagonist MRL-677 was characterized using an in vivo model of monocyte migration. To determine the relative roles of CCR2 and CX3CR1 in vascular remodeling, normal or CX3CR1 deficient mice were treated with MRL-677. After 14 days, the level of intimal hyperplasia in the artery was visualized by paraffin sectioning and histology of the hind limbs.ResultsMRL-677 is a CCR2 antagonist that is effective in blocking macrophage trafficking in a peritoneal thioglycollate model. Intimal hyperplasia resulting from vascular injury was also assessed in mice. Based on the whole-blood potency of MRL-677, sufficient drug levels were maintained for the entire 14 day experimental period to afford good coverage of mCCR2 with MRL-677. Blocking CCR2 with MRL-677 resulted in a 56% decrease in the vascular injury response (n = 9, p < 0.05) in normal animals. Mice in which both CCR2 and CX3CR1 pathways were targeted (CX3CR1 KO mice given MRL-677) had an 88% decrease in the injury response (n = 6, p = 0.009).ConclusionIn this study we have shown that blocking CCR2 with a low molecular weight antagonist ameliorates the inflammatory response to vascular injury. The protective effect of CCR2 blockade is increased in the presence of CX3CR1 deficiency suggesting that CX3CR1 and CCR2 have non-redundant functions in the progression of vascular inflammation.

Conformational studies of 3-amino-1-alkyl-cyclopentane carboxamide CCR2 antagonists leading to new spirocyclic antagonists.

In an effort to shed light on the active binding conformation of our 3-amino-1-alkyl-cyclopentane carboxamide CCR2 antagonists, we prepared several conformationally constrained analogs resulting from backbone cyclization. Evaluation of CCR2 binding affinities for these analogs gave insight into the optimal relative positions of the piperidine and benzylamide moieties while simultaneously leading to the discovery of a new, potent lead type based upon a spirocyclic acetal scaffold.

Heterocyclic acetamide and benzamide derivatives as potent and selective β3-adrenergic receptor agonists with improved rodent pharmacokinetic profiles

A series of amide derived beta(3)-adrenergic receptor (AR) agonists is described. The discovery and optimization of several series of compounds derived from 1, is used to lay the SAR foundation for second generation beta(3)-AR agonists for the treatment of overactive bladder.

Pharmacological Characterization of a Novel Beta 3 Adrenergic Agonist, Vibegron: Evaluation of Antimuscarinic Receptor Selectivity for Combination Therapy for Overactive Bladder

Although the physiologic role of muscarinic receptors in bladder function and the therapeutic efficacy of muscarinic antagonists for the treatment of overactive bladder are well established, the role of β3-adrenergic receptors (β3ARs) and their potential as therapeutics is just emerging. In this manuscript, we characterized the pharmacology of a novel β3AR agonist vibegron (MK-4618, KRP-114V) and explored mechanistic interactions of β3AR agonism and muscarinic antagonism in urinary bladder function. Vibegron is a potent, selective full β3AR agonist across species, and it dose dependently increased bladder capacity, decreased micturition pressure, and increased bladder compliance in rhesus monkeys. The relaxation effect of vibegron was enhanced when combined with muscarinic antagonists, but differentially influenced by muscarinic receptor subtype selectivity. The effect was greater when vibegron was co-administered with tolterodine, a nonselective antagonist, compared with coadministration with darifenacin, a selective M3 antagonist. Furthermore, a synergistic effect for bladder strip relaxation was observed with the combination of a β3AR agonist and tolterodine in contrast to simple additivity with darifenacin. To determine expression in rhesus bladder, we employed a novel β3AR agonist probe, [3H]MRL-037, that selectively labels β3 receptors in both urothelium and detrusor smooth muscle. Vibegron administration caused a dose-dependent increase in circulating glycerol and fatty acid levels in rhesus and rat in vivo, suggesting these circulating lipids can be surrogate biomarkers. The translation of our observation to the clinic has yet to be determined, but the combination of β3AR agonists with M2/M3 antimuscarinics has the potential to redefine the standard of care for the pharmacological treatment of overactive bladder.