Collaborative Virtual Screening Identifies a 2-Aryl-4-aminoquinazoline Series with Efficacy in an In Vivo Model of Trypanosoma cruzi Infection.

Probing multiple proprietary pharmaceutical libraries in parallel via virtual screening allowed rapid expansion of the structure-activity relationship (SAR) around hit compounds with moderate efficacy against Trypanosoma cruzi, the causative agent of Chagas Disease. A potency-improving scaffold hop, followed by elaboration of the SAR via design guided by the output of the phenotypic virtual screening efforts, identified two promising hit compounds 54 and 85, which were profiled further in pharmacokinetic studies and in an in vivo model of T. cruzi infection. Compound 85 demonstrated clear reduction of parasitemia in the in vivo setting, confirming the interest in this series of 2-(pyridin-2-yl)quinazolines as potential anti-trypanosome treatments.

Collaborative virtual screening to elaborate an imidazo[1,2-a]pyridine hit series for visceral leishmaniasis.

An innovative pre-competitive virtual screening collaboration was engaged to validate and subsequently explore an imidazo[1,2-a]pyridine screening hit for visceral leishmaniasis. In silico probing of five proprietary pharmaceutical company libraries enabled rapid expansion of the hit chemotype, alleviating initial concerns about the core chemical structure while simultaneously improving antiparasitic activity and selectivity index relative to the background cell line. Subsequent hit optimization informed by the structure-activity relationship enabled by this virtual screening allowed thorough investigation of the pharmacophore, opening avenues for further improvement and optimization of the chemical series.

Novel acyl coenzyme A: diacylglycerol acyltransferase 1 inhibitors-synthesis and biological activities of N-(substituted heteroaryl)-4-(substituted phenyl)-4-oxobutanamides.

In a program to discover new small molecule diacylglycerol acyltransferase (DGAT)-1 inhibitors, screening of our in-house chemical library was carried out using recombinant human DGAT-1 enzyme. From this library, the lead compound 1a was identified as a new class of DGAT-1 inhibitor. A series of novel N-(substituted heteroaryl)-4-(substituted phenyl)-4-oxobutanamides 2 was designed from 1a, synthesized and evaluated for inhibitory activity against DGAT-1 enzyme. Among these compounds, N-(5-benzyl-4-phenyl-1,3-thiazol-2-yl)-4-(4,5-diethoxy-2-methylphenyl)-4-oxobutanamide 9 was found to exhibit potent inhibitory activity and good enzyme selectivities. Following administration in KKA(y) mice with 3 mg/kg high fat diet admixture for four weeks, 9 reduced body weight gain and white adipose tissue weight without affecting total food intake. These results suggested that the small molecule DGAT-1 inhibitor might have potential in the treatment of obesity and metabolic syndrome.

Antidyslipidemic potential of a novel farnesoid X receptor antagonist in a hamster model of dyslipidemia: Comparative studies of other nonstatin agents.

We attempted to clarify the therapeutic capability of antagonists of the farnesoid X receptor (FXR), a nuclear receptor that regulates lipid and bile acid metabolism. Herein, we report the antidyslipidemic effects of a novel synthesized FXR antagonist, compound-T1, utilizing a dyslipidemic hamster model. Compound-T1 selectively inhibited chenodeoxycholic acid-induced FXR activation (IC 50, 2.1 nmol·L-1). A hamster model of diet-induced hyperlipidemia was prepared to investigate the antidyslipidemic effects of compound-T1 through comparative studies of the nonstatin lipid-modulating agents ezetimibe, cholestyramine, and torcetrapib. In the hamster model, compound-T1 (6 mg·kg-1·day-1, p.o.) increased the level of plasma high-density lipoprotein (HDL)-cholesterol (+22.2%) and decreased the levels of plasma non-HDL-cholesterol (-43.6%) and triglycerides (-31.1%). Compound-T1 also increased hepatic cholesterol 7α-hydroxylase expression and fecal bile acid excretion, and decreased hepatic cholesterol content. Moreover, the hamster model could reflect clinical results of other nonstatin agents. Torcetrapib especially increased large HDL particles compared with compound-T1. Additionally, in the human hepatoma Huh-7 cells, compound-T1 enhanced apolipoprotein A-I secretion at a concentration close to its IC 50 value for FXR. Our results indicated the usefulness of the hamster model in evaluating FXR antagonists and nonstatin agents. Notably, compound-T1 exhibited beneficial effects on both blood non-HDL-cholesterol and HDL-cholesterol, which are thought to involve enhancement of cholesterol catabolism and apolipoprotein A-I production. These findings aid the understanding of the antidyslipidemic potential of FXR antagonists with a unique lipid and bile acid modulation.

Farnesoid X receptor antagonist exacerbates dyslipidemia in mice.

BACKGROUND: The effects of farnesoid X receptor (FXR) antagonists on plasma lipid profile in mice have not been investigated thus far. The aim of this study was to investigate the antidyslipidemic effects of an FXR antagonist in dyslipidemic mice, and to clarify the mechanisms underlying the lipid modulatory effect. METHODS: Compound-T0 (1-100 mg/kg) was orally administered to C57BL/6J mice fed a Western-type diet or low-density lipoprotein receptor knockout (LDLR-/-) mice fed a Western-type diet for a week, and plasma lipid levels were investigated. Effects on lipid clearance, hepatic triglyceride secretion after Triton WR-1339 challenge, and intestinal lipid absorption were investigated after multiple dosing. RESULTS: Compound-T0 significantly increased plasma level of non-high-density lipoprotein cholesterol in both C57BL/6 and LDLR-/- mice; in addition, it significantly increased plasma triglyceride level in LDLR-/- mice. Compound-T0 failed to enhance the clearance of 3,3'-dioctadecylindocarbocyanine (DiI)-labeled LDL in C57BL/6J mice. Although compound-T0 did not affect triglyceride clearance and hepatic triglyceride secretion, it significantly increased intestinal [3H]cholesterol absorption in LDLR-/- mice. CONCLUSIONS: It was found that the FXR antagonist, compound-T0 exacerbated dyslipidemia in mice because it enhanced intestinal lipid absorption via acceleration of bile acid excretion.

Effects of a farnesoid X receptor antagonist on hepatic lipid metabolism in primates.

We aimed to elucidate the mechanism underlying the anti-dyslipidemic effect of compound-T3, a farnesoid X receptor antagonist, by investigating its effects on hepatic lipid metabolism in non-human primates. We administered lipid-lowering drugs for 7 days to cynomolgus monkeys receiving a high-fat diet, and subsequently measured the levels of lipid parameters in plasma, feces, and hepatic tissue fluids. Compound-T3 (0.3 and 3mg/kg p.o.) significantly decreased the plasma levels of non-high-density lipoprotein (non-HDL) cholesterol and apolipoprotein B in a dose-dependent manner. It also decreased the mRNA levels of hepatic small heterodimer partner-1, induced the mRNA expression of hepatic cholesterol 7α-hydroxylase, reduced hepatic cholesterol and triglyceride levels, increased fecal bile acid excretion, and upregulated the expression of hepatic low-density lipoprotein (LDL) receptor. Furthermore, compound-T3 significantly increased plasma HDL cholesterol and apolipoprotein A-I levels. The mRNA expression levels of hepatic apolipoprotein A-I tended to increase after compound-T3 treatment. Compound-T3 also induced accumulation of hepatic bile acids and decreased the mRNA expression levels of the hepatic bile acid export pump. The effects of cholestyramine (300mg/kg p.o.) on the plasma and hepatic lipid parameters were similar to those of compound-T3, and it increased fecal bile acid levels without causing accumulation of hepatic bile acids. These findings suggest that LDL receptor-mediated hepatic LDL incorporation due to cholesterol catabolism catalyzed by cholesterol 7α-hydroxylase decreases plasma non-HDL cholesterol levels. Upregulation of hepatic apolipoprotein A-I mRNA expression may partially contribute to the increase in HDL cholesterol levels mediated by compound-T3.

Antidyslipidemic effects of a farnesoid X receptor antagonist in primates.

AIMS: We investigated antidyslipidemic effects of a farnesoid X receptor antagonist compound-T3 in non-human primates as a novel treatment approach for dyslipidemia. MAIN METHODS: Cynomolgus monkeys were fed a high-fat diet over 3 weeks. Drugs were administered to the monkeys for a week, and their plasma and fecal lipid parameters were measured. KEY FINDINGS: Compound-T3 dose-dependently decreased the plasma non-high-density lipoprotein (non-HDL) cholesterol and apolipoprotein B levels in high-fat diet-fed cynomolgus monkeys. The plasma levels of 7α-hydroxy-4-cholesten-3-one, a marker of hepatic cholesterol 7α-hydroxylase activity, and total fecal bile acid levels increased, suggesting that the hypocholesterolemic effects would be dependent on the activation of cholesterol catabolism in the liver. Compound-T3 significantly increased the plasma levels of HDL cholesterol and apolipoprotein A-I. In this condition, the cholesterol absorption inhibitor ezetimibe significantly decreased the plasma non-HDL cholesterol levels and increased the fecal cholesterol levels without affecting plasma HDL cholesterol and triglyceride levels. Bile acid sequestrant cholestyramine tended to decrease plasma non-HDL cholesterol and increase fecal bile acid levels. The cholesteryl ester transfer protein inhibitor torcetrapib significantly increased plasma HDL cholesterol levels without affecting plasma non-HDL cholesterol and fecal cholesterol levels. SIGNIFICANCE: The results of ezetimibe, cholestyramine, and torcetrapib treatments indicate that our high-fat diet fed monkey model would be a preferred animal model for studying non-statin type antidyslipidemic drugs. Compound-T3 significantly decreased non-HDL cholesterol levels and increased HDL cholesterol levels in the monkey model, suggesting that a farnesoid X receptor antagonist could be a therapeutic option in human dyslipidemia.

Combinational effects of farnesoid X receptor antagonist and statin on plasma lipid levels and low-density lipoprotein clearance in guinea pigs.

AIMS: We previously reported anti-dyslipidemic effects of a farnesoid X receptor antagonist in monkeys. In this study, we compared the cholesterol-lowering effects of single and combined administration of a farnesoid X receptor antagonist, compound-T8, and the 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor atorvastatin in a guinea pig model. MAIN METHODS: Plasma levels of 7α-hydroxy-4-cholesten-3-one, a marker of hepatic cholesterol 7α-hydroxylase activity, were measured after a single administration of compound-T8. The effects of compound-T8 or atorvastatin on plasma cholesterol levels and low-density lipoprotein (LDL) clearance were investigated after 14 or 16 days of repeated dosing, respectively. Fractional catabolic rate of plasma LDL was estimated by intravenous injection of DiI-labeled human LDL. The cholesterol-lowering effects of combination therapy were investigated after 7 days of repeated treatment. KEY FINDINGS: Compound-T8 (10 and 30 mg/kg) increased plasma 7α-hydroxy-4-cholesten-3-one levels in a dose-dependent manner. Single administration of compound-T8 (30 mg/kg) and atorvastatin (30 mg/kg) reduced plasma non-high-density lipoprotein (non-HDL) cholesterol levels by 48% and 46%, respectively, and increased clearance of plasma DiI-labeled LDL by 29% and 35%, respectively. Compound-T8 (10mg/kg) or atorvastatin (10mg/kg) reduced non-HDL cholesterol levels by 19% and 25%, respectively, and combination therapy showed an additive effect and lowered cholesterol levels by 48%. SIGNIFICANCE: Similar to atorvastatin, compound-T8 reduced plasma non-HDL cholesterol levels accompanied with accelerated LDL clearance in guinea pigs. Combination therapy additively decreased plasma non-HDL cholesterol levels. Therefore, monotherapy with a farnesoid X receptor antagonist and combination therapy of a farnesoid X receptor antagonist with atorvastatin would be attractive dyslipidemia treatment options.

Coenzyme A: diacylglycerol acyltransferase 1 inhibitor ameliorates obesity, liver steatosis, and lipid metabolism abnormality in KKAy mice fed high-fat or high-carbohydrate diets.

Coenzyme A (CoA):diacylglycerol acyltransferase 1 (DGAT1) is 1 of the 2 known DGAT enzymes that catalyze the final and only committed step in triacylglycerol synthesis; this enzyme is considered to be a potential therapeutic target in metabolic disorders such as obesity and its related lipid abnormalities. Compound-Z, a novel specific small-molecule DGAT1 inhibitor, significantly reduced adipose tissue weight and tended to hepatic lipid accumulation in genetically obese KKAy mice. These actions were shown to almost the same extent in both a high-fat feeding condition in which triacylglycerols are synthesized mainly via exogenous fatty acid and a low-fat, high-carbohydrate feeding condition in which triacylglycerols are synthesized mainly via de novo fatty acid synthesis. This inhibitor also significantly reduced plasma and/or hepatic cholesterol levels in KKAy mice in a high-fat feeding condition. This cholesterol-lowering effect was suggested to be due to mainly decreases in cholesterol absorption from the small intestine. These results suggest that Compound-Z is a promising and attractive agent not only for the treatment of obesity but also hepatic steatosis and circulating lipid abnormalities that are the leading causes of atherosclerosis.

Pyrrolidinedione derivatives as antibacterial agents with a novel mode of action.

The pseudopeptide pyrrolidinedione natural products moiramide B and andrimid represent a new class of antibiotics that target bacterial fatty acid biosynthesis. Structure-activity relationship (SAR) studies revealed a high degree of variability for the fatty acid side chain, allowing optimization of physicochemical parameters, and a restricted SAR for the pyrrolidinedione group, indicating major relevance of this subunit for efficient target binding.

Synthesis and structure-activity relationships of novel IKK-beta inhibitors. Part 2: Improvement of in vitro activity.

A series of 2-amino-3-cyano-4-alkyl-6-(2-hydroxyphenyl)pyridine derivatives was synthesized and evaluated as IkappaB kinase beta (IKK-beta) inhibitors. Substitution of an aminoalkyl group for the aromatic group at the 4-position on the core pyridine ring resulted in a marked increase in both kinase enzyme and cellular potencies, and provided potent IKK-beta inhibitors with IC(50) values of below 100 nM.

Discovery of novel and selective IKK-beta serine-threonine protein kinase inhibitors. Part 1.

IkappaB kinase beta (IKK-beta) is a serine-threonine protein kinase critically involved in the activation of the transcription factor Nuclear Factor kappa B (NF-kappaB) in response to various inflammatory stimuli. We have identified a small molecule inhibitor of IKK-beta. Optimization of the lead compound resulted in improvements in both in vitro and in vivo potency, and provided IKK-beta inhibitors exhibiting potent activity in an acute cytokine release model (LPS-induced TNFalpha).

Synthesis and structure-activity relationships of novel IKK-beta inhibitors. Part 3: Orally active anti-inflammatory agents.

A series of 2-amino-3-cyano-4-alkyl-6-(2-hydroxyphenyl)pyridine derivatives was synthesized and evaluated as I kappaB kinase beta (IKK-beta) inhibitors. Modification of a novel IKK-beta inhibitor 1 (IKK-beta IC(50)=1500 nM, Cell IC(50)=8000 nM) at the 4-phenyl ring and 6-phenol group on the pyridine core ring resulted in a marked increased in biological activities. An optimized compound, 2-amino-6-[2-(cyclopropylmethoxy)-6-hydroxyphenyl]-4-piperidin-4-yl nicotinonitrile, exhibited excellent in vitro profiles (IKK-beta IC(50)=8.5 nM, Cell IC(50)=60 nM) and a strong oral efficacy in in vivo anti-inflammatory assays (significant effects at 1mg/kg, po in arachidonic acid-induced ear edema model in mice).