Keith Bowers

ENDOGENOUS MONOCYTE CHEMOATTRACTANT PROTEIN-1 RECRUITS MONOCYTES IN THE ZYMOSAN PERITONITIS MODEL

The role of monocyte chemoattractant protein‐1 (MCP‐1) in the recruitment of blood‐derived monocytes in a model of zymosan peritoneal inflammation was investigated. After zymosan injection (1 mg) a rapid influx of polymorphonuclear leukocytes (PMN) and monocytes into the peritoneal cavity associated with mouse MCP‐1 (JE) gene activation and protein secretion in the exudates occurred. MCP‐1 production (maximal at 4 h) preceded the accumulation of monocytes (F4/80‐positive cells, maximally recovered between 16 and 24 h). Treatment of mice with a single injection of anti‐mouse MCP‐1 antibody inhibited 16‐h monocyte accumulation by ~40%, however, a significant decrease in the number of PMN was also measured. Finally, intraperitoneal injection of murine recombinant MCP‐1 (1 μg) produced a selective accumulation of monocytes (F4/80‐positive cells) into the peritoneal cavity. In conclusion, we show the novel existence of a strict relationship between MCP‐1 production and leukocyte accumulation in this model of acute inflammation. J. Leukoc. Biol. 63: 108–116; 1998.

Characterization of a selective and potent antagonist of human P2X7 receptors, AZ11645373

The ATP‐gated P2X7 receptor has been shown to play a role in several inflammatory processes, making it an attractive target for anti‐inflammatory drug discovery. We have recently identified a novel set of cyclic imide compounds that inhibited P2X7 receptor‐mediated dye uptake in human macrophage THP‐1 cells. In this study the actions and selectivity of one of these compounds, AZ11645373, were characterized.

The effects of P2X7 receptor antagonists on the formation and function of human osteoclasts in vitro.

The P2X7 receptor (P2X7R) has been implicated in the process of multinucleation and cell fusion. We have previously demonstrated that blockade of P2X7Rs on osteoclast precursors using a blocking antibody inhibited multinucleated osteoclast formation in vitro, but that P2X7R KO mice maintain the ability to form multinucleated osteoclasts. This apparent contradiction of the role the P2X7R plays in multinucleation has prompted us to examine the effect of the most commonly used and recently available P2X7R antagonists on osteoclast formation and function. When added to recombinant RANKL and M-CSF human blood monocytes cultures, all but one compound, decreased the formation and function of multinucleated TRAP-positive osteoclasts in a concentration-dependent manner. These data provide further evidence for the role of the P2X7R in the formation of functional human multinucleated osteoclasts and highlight the importance of selection of antagonists for use in long-term experiments.

The discovery of AZD9164, a novel muscarinic M3 antagonist

The optimization of a new series of muscarinic M(3) antagonists is described, leading to the identification of AZD9164 which was progressed into the clinic for evaluation of its potential as a treatment for COPD.

Scaffold-hopping with zwitterionic CCR3 antagonists: identification and optimisation of a series with good potency and pharmacokinetics leading to the discovery of AZ12436092.

The discovery and optimisation of a series of zwitterionic CCR3 antagonists is described. Optimisation of the structure led to AZ12436092, a compound with excellent selectivity over activity at hERG and outstanding pharmacokinetics in preclinical species.

The discovery of new spirocyclic muscarinic M3 antagonists

The optimisation of a new series of high potency muscarinic M3 antagonists, derived from high throughput screening library hit is described.

The design of a novel series of muscarinic receptor antagonists leading to AZD8683, a potential inhaled treatment for COPD.

A novel series of muscarinic receptor antagonists was developed, with the aim of identifying a compound with high M3 receptor potency and a reduced risk of dose-limiting side effects with potential for the treatment of COPD. Initial compound modifications led to a novel cycloheptyl series, which was improved by focusing on a quinuclidine sub-series. A wide range of N-substituents was evaluated to determine the optimal substituent providing a high M3 receptor potency, high intrinsic clearance and high human plasma protein binding. Compounds achieving in vitro study criteria were selected for in vivo evaluation. Pharmacokinetic half-lives, inhibition of bronchoconstriction and duration of action, as well as systemic side effects, induced by the compounds were assessed in guinea-pig models. Compounds with a long duration of action and good therapeutic index were identified and AZD8683 was selected for progression to the clinic.

The discovery of CCR3/H1 dual antagonists with reduced hERG risk

A series of dual CCR3/H(1) antagonists based on a bispiperidine scaffold were discovered. Introduction of an acidic group overcame hERG liability. Bioavailability was optimised by modulation of physico-chemical properties and physical form to deliver a compound suitable for clinical evaluation.

Discovery and evolution of phenoxypiperidine hydroxyamide dual CCR3/H1 antagonists. Part I

The discovery of potent small molecule dual antagonists of the human CCR3 and H(1) receptors is described for the treatment of allergic diseases, for example, asthma and allergic rhinitis. Optimizing in vitro potency and metabolic stability, starting from a CCR1 lead compound, led to compound 20 with potent dual CCR3/H(1) activity and in vitro metabolic stability.

Discovery and evolution of phenoxypiperidine hydroxyamide dual CCR3/H1 antagonists. Part II: Optimising in vivo clearance

The second part of this communication focuses on the resolution of issues surrounding the series of hydroxyamide phenoxypiperidine CCR3/H(1) dual antagonists described in Part I. This involved further structural exploration directed at reducing metabolism and leading to the identification of compound 60 with a greatly improved in vivo pharmacokinetic profile.