Cytokine release and expression induced by OmpA proteins from the Gram-negative anaerobes, Porphyromonas asaccharolytica and Bacteroides fragilis

OmpA proteins from Gram-negative anaerobes Porphyromonas asaccharolytica and Bacteroides fragilis induced release and expression of IL-1alpha, tumor necrosis factor (TNF)-alpha, IFN-gamma, IL-6, and IL-10 from murine splenocytes in vitro in a dose-dependent fashion. The release of the cytokines induced by B. fragilis Bf-OmpA was at much lower levels compared with P. asaccharolytica Omp-PA; Bf-OmpA did not induce release of IL-10. Omp-PA and Bf-OmpA were able to upregulate mRNA expression of the tested cytokines. The results obtained with refolded Bf-OmpA were similar to those with native Bf-OmpA. The data presented in this research demonstrate for the first time that Omps from anaerobic bacteria can induce the release of cytokines, suggesting that Omp-PA and Bf-OmpA may play important roles in the pathogenic processes of these bacteria.     

Structure-activity relationships of anthranilamide-based factor Xa inhibitors containing piperidinone and pyridinone P4 moieties

Introduction of the phenyl piperidinone and phenyl pyridinone P4 moieties in the anthranilamide scaffold led to potent, selective, and orally bioavailable inhibitors of factor Xa. Anthranilamide 28 displayed comparable efficacy to apixaban in the rabbit arteriovenous-shunt (AV) thrombosis model.     

Potent P1' biphenylmethyl substituted aggrecanase inhibitors.

A series of cis-1(S)2(R)-amino-2-indanol based compounds with a biphenylmethyl group at the P1' position was found to be potent aggrecanase inhibitors. Both compounds 2j and 2n possessed very high aggrecanase affinity (IC(50)=1.5nM), and showed excellent selectivity over MMP-1 and MMP-9, with moderate selectivity against MMP-2.     

Achieving structural diversity using the perpendicular conformation of alpha-substituted phenylcyclopropanes to mimic the bioactive conformation of ortho-substituted biphenyl P4 moieties: discovery of novel, highly potent inhibitors of Factor Xa

Ortho-substituted biphenyl moieties are widely used in drug design. We herein report a successful use of the perpendicular conformation of the alpha-substituted phenylcyclopropyl groups to mimic the aplanar, biologically active conformation of the ortho-substituted biphenyl moieties to achieve structural diversity. This is exemplified by the design and synthesis of a series of highly potent pyrazole bicyclic-based Factor Xa (FXa) inhibitors bearing alpha-substituted phenylcyclopropyl P4 moieties. The designed perpendicular conformation was confirmed by the X-ray structure of FXa-bound compound 2r. The potential structural basis for the high FXa potency in the phenylcyclopropyl P4 analogs and their improved FXa inhibitory activities compared with the biphenyl P4 counterparts are discussed.     

Structure-activity relationship and pharmacokinetic profile of 5-ketopyrazole factor Xa inhibitors

Efforts to further optimize the clinical candidate razaxaban have led to a new series of pyrazole-based factor Xa (fXa) inhibitors. Designed to prevent the potential formation of primary aniline metabolites in vivo, the nitrogen of the carboxamido linker between the pyrazole and proximal phenyl moiety of the razaxaban scaffold was replaced with a methylene group. The resulting ketones demonstrated excellent potency and selectivity for fXa but initially had poor oral bioavailability. Optimization by conversion from a P1 aminobenzisoxazole to a P1 p-methoxyphenyl residue, replacing the 3-trifluoromethylpyrazole with a 3-amidopyrazole, and employing a pyridone P4 group provided a fXa inhibitor with a potency and pharmacokinetic profile equivalent to that of razaxaban and improved selectivity over thrombin.     

Sulfonamidolactam inhibitors of coagulation factor Xa

As part of an effort to identify novel backups for previously reported pyrazole-based coagulation Factor Xa inhibitors, the pyrazole 5-carboxamide moiety was replaced by 3-(sulfonylamino)-2-piperidone. This led to the identification of a structurally diverse chemotype that was further optimized to incorporate neutral or weakly basic aryl and heteroaryl P1 groups while maintaining good potency versus Factor Xa. Substitution at the sulfonamide nitrogen provided further improvements in potency and as did introduction of alternate P4 moieties.     

Highly efficacious factor Xa inhibitors containing α-substituted phenylcycloalkyl P4 moieties

We previously disclosed a series of highly potent FXa inhibitors bearing α-substituted (CH₂NR¹R²) phenylcyclopropyl P4 moieties in the pyrazolodihydropyridone core system. Herein, we describe our continuous SAR efforts in this series. Effects of the C-3 substitution of the pyrazolodihydropyridone core and the α-substitution (R group) of the cyclopropyl ring on FXa binding affinity (FXa K_i), human plasma anticoagulant activity (PT EC_2×) and permeability are discussed. A set of compounds obtained from optimization of the R group and the C-3 substituent were orally bioavailable in dogs. Furthermore, representative compounds were highly efficacious in the rabbit arterio-venous shunt thrombosis model (EC₅₀s = 29–81 nM).