Development of a gut microbe-targeted nonlethal therapeutic to inhibit thrombosis potential.

Trimethylamine N-oxide (TMAO) is a gut microbiota-derived metabolite that enhances both platelet responsiveness and in vivo thrombosis potential in animal models, and TMAO plasma levels predict incident atherothrombotic event risks in human clinical studies. TMAO is formed by gut microbe-dependent metabolism of trimethylamine (TMA) moiety-containing nutrients, which are abundant in a Western diet. Here, using a mechanism-based inhibitor approach targeting a major microbial TMA-generating enzyme pair, CutC and CutD (CutC/D), we developed inhibitors that are potent, time-dependent, and irreversible and that do not affect commensal viability.

The flavonoid cyanidin blocks binding of the cytokine interleukin-17A to the IL-17RA subunit to alleviate inflammation in vivo.

Cyanidin, a key flavonoid that is present in red berries and other fruits, attenuates the development of several diseases, including asthma, diabetes, atherosclerosis, and cancer, through its anti-inflammatory effects. We investigated the molecular basis of cyanidin action. Through a structure-based search for small molecules that inhibit signaling by the proinflammatory cytokine interleukin-17A (IL-17A), we found that cyanidin specifically recognizes an IL-17A binding site in the IL-17A receptor subunit (IL-17RA) and inhibits the IL-17A/IL-17RA interaction.

Phosphoramidate prodrugs of (-)-β-D-(2R,4R)-dioxolane-thymine (DOT) as potent anti-HIV agents.

Background: Nucleoside reverse transcriptase inhibitors (NRTIs) are an effective class of agents that has played a vital role in the treatment of HIV infections. (-)-β-D-(2R,4R)-dioxolane-thymine (DOT) is a thymidine analogue that is active against wild-type and NRTI-resistant HIV-1 mutants. It has been shown that the anti-HIV activity of DOT is limited due to poor monophosphorylation.

Synthesis of diastereomerically pure nucleotide phosphoramidates.

Prodrugs of therapeutic nucleoside monophosphates masked as phosphoramidate derivatives have become an increasingly important class of antiviral drugs in pharmaceutical research for delivering nucleotides in vitro and in vivo. Conventionally, phosphoramidate derivatives are prepared as a mixture of two diastereomers. We report a class of stable phosphoramidating reagents containing an amino acid ester and two phenolic groups, one unsubstituted and the other with electron-withdrawing substituents.

Stereoselective synthesis of PSI-352938: a β-D-2'-deoxy-2'-α-fluoro-2'-β-C-methyl-3',5'-cyclic phosphate nucleotide prodrug for the treatment of HCV.

PSI-352938 is a novel 2'-deoxy-2'-α-fluoro-2'-β-C-methyl 3',5'-cyclic phosphate nucleotide prodrug currently under investigation for the treatment of hepatitis C virus (HCV) infection. PSI-352938 demonstrated superior characteristics in vitro that include broad genotype coverage, superior resistance profile, and high levels of active triphosphate in vivo in the liver compared to our first and second generation nucleoside inhibitors of this class. Consequently, PSI-352938 was selected for further development and an efficient and scalable synthesis was sought to support clinical development.

Discovery of PSI-353661, a Novel Purine Nucleotide Prodrug for the Treatment of HCV Infection.

Hepatitis C virus afflicts approximately 180 million people worldwide, and the development of direct acting antivirals may offer substantial benefit compared to the current standard of care. Accordingly, prodrugs of 2'-deoxy-2'-fluoro-2'-C-methylguanosine monophosphate analogues were prepared and evaluated for their anti-HCV efficacy and tolerability. These prodrugs demonstrated >1000 fold greater potency than the parent nucleoside in a cell-based replicon assay as a result of higher intracellular triphosphate levels.

2'-deoxy-2'-α-fluoro-2'-β-C-methyl 3',5'-cyclic phosphate nucleotide prodrug analogs as inhibitors of HCV NS5B polymerase: discovery of PSI-352938.

A series of novel 2'-deoxy-2'-α-fluoro-2'-β-C-methyl 3',5'-cyclic phosphate nucleotide prodrug analogs were synthesized and evaluated for their in vitro anti-HCV activity and safety. These prodrugs demonstrated a 10-100-fold greater potency than the parent nucleoside in a cell-based replicon assay due to higher cellular triphosphate levels. Our structure-activity relationship (SAR) studies provided compounds that gave high levels of active triphosphate in rat liver when administered orally to rats.

Discovery of a β-d-2'-deoxy-2'-α-fluoro-2'-β-C-methyluridine nucleotide prodrug (PSI-7977) for the treatment of hepatitis C virus.

Hepatitis C virus (HCV) is a global health problem requiring novel approaches for effective treatment of this disease. The HCV NS5B polymerase has been demonstrated to be a viable target for the development of HCV therapies. β-d-2'-Deoxy-2'-α-fluoro-2'-β-C-methyl nucleosides are selective inhibitors of the HCV NS5B polymerase and have demonstrated potent activity in the clinic.

Synthesis and anti-HCV activity of 3',4'-oxetane nucleosides.

Hepatitis C virus afflicts approximately 180 million people worldwide and currently there are no direct acting antiviral agents available to treat this disease. Our first generation nucleoside HCV inhibitor, RG7128 has already established proof-of-concept in the clinic and is currently in phase IIb clinical trials. As part of our continuing efforts to discover novel anti-HCV agents, 3',4'-oxetane cytidine and adenosine nucleosides were prepared as inhibitors of HCV RNA replication.

An efficient and diastereoselective synthesis of PSI-6130: a clinically efficacious inhibitor of HCV NS5B polymerase.

R7128 is the prodrug of 2'-deoxy-2'-fluoro-2'-C-methylcytidine (PSI-6130), a potent and selective inhibitor of HCV NS5B polymerase. Currently, R7128 is in clinical trials for the treatment of HCV infection. To support clinical development efforts, we needed an efficient and scalable synthesis of PSI-6130.

Synthesis and structure-activity relationships of novel anti-hepatitis C agents: N3,5'-cyclo-4-(beta-D-ribofuranosyl)-vic-triazolo[4,5-b]pyridin-5-one derivatives.

Several 6- and 7-monosubstituted N3,5'-cyclo-4-(beta-d-ribofuranosyl)-vic-triazolo[4,5-b]pyridin-5-one derivatives as well as the 5-thiono analogue were synthesized, providing structure-anti-hepatitis C virus (HCV) activity relationships for the series. Among the compounds synthesized, the 6-bromo, 7-methylamino, and 5-thiono analogues exhibited more potent anti-HCV activity in an HCV subgenomic replicon cell based assay (EC90 = 1.9, 7.

Synthesis of beta-enantiomers of N4-hydroxy-3'-deoxypyrimidine nucleosides and their evaluation against bovine viral diarrhoea virus and hepatitis C virus in cell culture.

N4-Hydroxycytidine (NHC) was recently reported to have anti-pestivirus and anti-hepacivirus activity. It is thought that this nucleoside acts as a weak alternative substrate for the hepatitis C virus (HCV) polymerase. In addition to NHC, 3'-deoxyuridine (3'-dU) was found to inhibit bovine diarrhoea virus (BVDV) production by 1 log10 at 37.

Challenges in antimicrobial drug discovery and the potential of nucleoside antibiotics.

Antimicrobial resistance in hospital and community settings is growing at an alarming rate and has been attributed to such organisms as methicillin-resistant staphylococcus aureus, staphylococci with decreased susceptibility to vancomycin, vancomycin-resistant enterococci, multi-drug resistant pseudomonas spp., klebsiella spp., enterobacter spp, and acinetobacter spp.

N4-acyl-modified D-2',3'-dideoxy-5-fluorocytidine nucleoside analogues with improved antiviral activity.

A series of 2',3'-dideoxy (D2) and 2',3'-didehydro-2',3'-dideoxy (D4) 5-fluorocytosine nucleosides modified with substituted benzoyl, heteroaromatic carbonyl, cycloalkylcarbonyl and alkanoyl at the N4-position were synthesized and evaluated for anti-human immunodeficiency virus type 1 (HIV-1) and anti-hepatitis B virus (HBV) activity in vitro. For most D2-nucleosides, N4-substitutions improved the anti-HIV-1 activity markedly without increasing the cytotoxicity. In the D4-nucleosides series, some of the substituents at the N4-position enhanced the anti-HIV-1 activity with a modest increase in the cytotoxicity.

Ribonucleoside analogue that blocks replication of bovine viral diarrhea and hepatitis C viruses in culture.

A base-modified nucleoside analogue, beta-D-N(4)-hydroxycytidine (NHC), was found to have antipestivirus and antihepacivirus activities. This compound inhibited the production of cytopathic bovine viral diarrhea virus (BVDV) RNA in a dose-dependant manner with a 90% effective concentration (EC(90)) of 5.4 microM, an observation that was confirmed by virus yield assays (EC(90) = 2 microM).