Jacqueline Bonnet

Development of an enzyme-linked immunoassay for the quantification of YKL-40 (cartilage gp-39) in guinea pig serum using hen egg yolk antibodies

An indirect competition immunoassay for the quantification of YKL-40 (cartilage gp-39, Chondrex) in guinea pig serum has been developed using egg yolk antibodies (IgY). The immune response of hens to YKL-40 was verified by immunoblot analyses. Highly specific antibodies were obtained 30 days after the first injection. The ELISA was developed in 96-well microtiter plates with quadruplicate determinations for each point. The assay was based on the ability of YKL-40 present in serum to displace the binding of antibodies to the coated antigen. An inhibition mixture containing standard YKL-40 or guinea pig serum, diluted 1/5, and primary antibodies, diluted 1/5000, was allowed to equilibrate for 2 h at room temperature and dispensed for 16 h at 4 degrees C in wells coated with 1 microg/ml of YKL-40. Detection was achieved by the addition of rabbit anti-chicken antibodies conjugated to peroxidase followed by tetramethylbenzidine. Specificity was assessed by parallelism between a dilution curve of serum and standard YKL-40. The sensitivity of detection was 10 ng/ml. Intra- and interassay coefficients of variation were both 8.7%. The analytical recovery was 101.5+/-5.4% (mean+/-standard deviation (SD), n=9). The YKL-40 concentration in serum from 12 adult guinea pigs was 330+/-216 ng/ml (mean+/-SD) with a lower value of 164 ng/ml and an upper value of 982 ng/ml. In contrast to the rat, a dilution curve of rabbit serum gave parallelism with the guinea pig standard, suggesting recognition of a similar epitope. Possible applications of the assay in the guinea pig include disease models where YKL-40 is overexpressed and could be used as a marker, i.e. osteoarthritis, rheumatoid arthritis, cancer, liver fibrosis, atherosclerosis and more generally, pathologies with increased tissue remodeling.

Pharmacological profile of a novel series of NK1 antagonists. In vitro and in vivo potency of benzimidazolone derivatives

Summary By low throughput examination of our chemical library, compound 7 was selected as a lead NK1 antagonist with a Ki of 7.1 nM. Modifications of its structure led to the finding that the in vitro potency could be markedly enhanced by disubstituting the anilino phenyl ring as in compounds 13 or 22. Human binding data correlated rather well with results obtained with in vitro animal smooth muscle preparations. Several agents proved to possess antinociceptive properties as exemplified in the hot-plate test in mice; compound 13 was the most active with ED50 of 0.001 and 0.3 mg/kg after iv and po administration respectively. Furthermore, antagonist 71 was found to be a potent inhibitor of SP-induced bronchoconstriction in guinea-pigs with an ED50 between 0.1 and 0.03 mg/kg iv. Furthermore, upon oral administration, 71 was observed to be active in a model of SP-induced bronchial hyper-sensitivity in mice, with an ID50 of around 3 mg/kg.

General synthesis of α-substituted 3-bisaryloxy propionic acid derivatives as specific mmp inhibitors

Modulations of alpha and aryl substitutions on 3-aryloxy propionic acid hydroxamates led to novel and potent inhibitors of MMP-2,3,9 and 13, and selectivity versus MMP-1.