Synthesis and evaluation of novel modified γ-lactam prostanoids as EP4 subtype-selective agonists.

To identify chemically and metabolically stable subtype-selective EP4 agonists, design and synthesis of a series of modified γ-lactam prostanoids has been continued. Prostanoids bearing 2-oxo-1,3-oxazolidine, 2-oxo-1,3-thiazolidine and 5-thioxopyrrolidine as a surrogate for the γ-hydroxycyclopentanone without a troublesome 11-hydroxy group were identified as highly subtype-selective EP4 agonists. Among the tested, several representative compounds demonstrated in vivo efficacy after oral dosing in rats.

Discovery of orally available 8-aza-5-thiaProstaglandin E1 analogs as highly selective EP4 agonists.

Analogs 8-aza-16-aryl prostaglandin E(1) (PGE(1)) and 8-aza-5-thia-16-arylPGE(1) were synthesized and evaluated with respect to their subtype receptor affinity and EP4 agonist activity for the purposes of identifying subtype-selective EP4 agonists that demonstrate oral efficacy. Using an inhibition assay of lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF)-α production in rats, representative compounds were evaluated for their pharmacokinetic profiles and in vivo efficacy. Structure-activity relationships (SARs) were characterized and presented.

Endothelium-dependent vascular responses induced by leukotriene B4.

Leukotriene B(4) (LTB(4)) is an inflammatory mediator derived from the 5-lipoxygenase pathway of arachidonic acid metabolism and has recently implicated in the pathogenesis of atherosclerosis. There are two membrane bound receptors for LTB(4): BLT(1) and BLT(2), which represent the high and low affinity receptors, respectively. BLT receptors are expressed on leukocytes, and LTB(4) is a potent chemoattractant for neutrophils, eosinophils, and T lymphocytes.

Effects of a prostaglandin EP4 agonist, ONO-4819, and risedronate on trabecular microstructure and bone strength in mature ovariectomized rats.

The effects of a prostaglandin EP4 agonist, ONO-4819, and risedronate, a representative anti-resorptive drug, on trabecular microarchitecture and biomechanical properties were investigated in mature estrogen-deficient rats; and effects which affected microstructural components that contributed to the improvement of bone strength were also determined. Thirty-three-week-old OVX rats were treated with various doses of ONO-4819, risedronate, or their combination for 11 weeks. Bone mineral density (BMD), trabecular microstructure, and biomechanical strength were determined at the proximal tibia by peripheral quantitative CT, micro CT, and finite element analysis, respectively.

Leukotriene B4 is an indirectly acting vasoconstrictor in guinea pig aorta via an inducible type of BLT receptor.

Leukotriene B(4) (LTB(4)) is a potent leukocyte chemoattractant recently implicated in the pathogenesis of atherosclerosis. The aim of this study was to assess the effects of LTB(4) on isolated aortic preparations. Rings of guinea pig aorta were challenged with LTB(4) for recording mechanical responses and measurements of mediator release, and LTB(4) receptor (BLT(1)) expression was assessed by RT-PCR.

The contractile action of leukotriene B4 in the guinea-pig lung involves a vascular component.

Leukotriene B4 (LTB4) is a potent leukocyte chemoattractant, acting on specific receptors, BLT receptors. The aim of this study was to examine the mechanism of action of LTB4 in the guinea-pig lung, using strips of lung parenchyma (GPLP), spirals of trachea (GPT) and bronchus (GPB) and rings of pulmonary artery (GPPA). Mechanical responses were studied in organ baths, and mediator release was assessed using enzyme immuno assay.

Design and synthesis of a selective EP4-receptor agonist. Part 4: practical synthesis and biological evaluation of a novel highly selective EP4-receptor agonist.

A practical method of synthesizing a highly selective EP4-receptor agonist 1 using Corey lactone 2 as a key intermediate was developed. Selective methanesulfonylation of the primary alcohol of the diol 8 under the newly devised conditions followed by the protection of the remaining secondary alcohol are key reactions in this new method. Further biological evaluation of 1a-b is also reported.

Receptor preferences of cysteinyl-leukotrienes in the guinea pig lung parenchyma.

Two cysteinyl-leukotriene receptors, CysLT(1) and CysLT(2) receptors, have been cloned, but the contractions to cysteinyl-leukotrienes in the guinea pig lung parenchyma have been reported to be resistant to CysLT(2) receptor antagonism and to be only partially inhibited by CysLT(1) receptor antagonism. The receptor preferences of the individual cysteinyl-leukotrienes (leukotriene C(4), D(4) and E(4)) in the guinea pig lung parenchyma were studied in organ baths. CysLT(1) receptor antagonists competitively inhibited the contraction to leukotriene E(4), but exhibited only weak antagonism of contractions to leukotriene C(4) and D(4).