Design and synthesis of selective, dual fatty acid binding protein 4 and 5 inhibitors.

Dual inhibition of fatty acid binding proteins 4 and 5 (FABP4 and FABP5) is expected to provide beneficial effects on a number of metabolic parameters such as insulin sensitivity and blood glucose levels and should protect against atherosclerosis. Starting from a FABP4 selective focused screening hit, biostructure information was used to modulate the selectivity profile in the desired way and to design potent dual FABP4/5 inhibitors with good selectivity against FABP3. With very good pharmacokinetic properties and no major safety alerts, compound 12 was identified as a suitable tool compound for further in vivo investigations.

Discovery of a Series of Indane-Containing NBTIs with Activity against Multidrug-Resistant Gram-Negative Pathogens.

The rise of multidrug-resistant (MDR) Gram-negative bacteria is a major global health problem necessitating the discovery of new classes of antibiotics. Novel bacterial topoisomerase inhibitors (NBTIs) target the clinically validated bacterial type II topoisomerases with a distinct binding site and mechanism of action to fluoroquinolone antibiotics, thus avoiding cross-resistance to this drug class. Here we report the discovery of a series of NBTIs incorporating a novel indane DNA binding moiety. X-ray cocrystal structures of compounds 2 and 17a bound to Staphylococcus aureus DNA gyrase-DNA were determined, revealing specific interactions with the enzyme binding pocket at the GyrA dimer interface and a long-range electrostatic interaction between the basic amine in the linker and the carboxylate of Asp83. Exploration of the structure-activity relationship within the series led to the identification of lead compound 18c, which showed potent broad-spectrum activity against a panel of MDR Gram-negative bacteria.

Novel Indane-Containing NBTIs with Potent Anti-Gram-Negative Activity and Minimal hERG Inhibition.

Novel bacterial topoisomerase inhibitors (NBTIs) make up a promising new class of antibiotics with the potential to combat the growing threat of antimicrobial resistance. Two key challenges in the development of NBTIs have been to obtain broad spectrum activity against multidrug-resistant Gram-negative bacteria and to diminish inhibition of the hERG cardiac ion channel. Here we report the optimization of a series of NBTIs bearing a novel indane DNA intercalating moiety. The addition of a basic, polar side chain connected to the indane by an ether or an N-linked secondary amide linkage together with a lipophilicity-lowering modification of the enzyme binding moiety led to compounds such as 2a and 2g which showed excellent broad spectrum potency and minimal hERG inhibition. Compound 2a demonstrated robust bactericidal in vivo activity in a mouse lung infection model with the strain P. aeruginosa ATCC 27853 which is resistant to several clinically relevant antibiotics. Rodent pharmacokinetic studies with 2a revealed an unusual profile characterized by rapid tissue distribution and a prolonged, flat terminal phase. This profile precluded further development of these compounds as potential new antibiotics.

Pyrido pyrimidinones as selective agonists of the high affinity niacin receptor GPR109A: optimization of in vitro activity.

Pyrido pyrimidinones are selective agonists of the human high affinity niacin receptor GPR109A (HM74A). They show no activity on the highly homologous low affinity receptor GPR109B (HM74). Starting from a high throughput screening hit the in vitro activity of the pyrido pyrimidinones was significantly improved providing lead compounds suitable for further optimization.

New Multidrug Efflux Inhibitors for Gram-Negative Bacteria.

Active efflux of antibiotics preventing their accumulation to toxic intracellular concentrations contributes to clinically relevant multidrug resistance. Inhibition of active efflux potentiates antibiotic activity, indicating that efflux inhibitors could be used in combination with antibiotics to reverse drug resistance. Expression of ramA by Salmonella enterica serovar Typhimurium increases in response to efflux inhibition, irrespective of the mode of inhibition. We hypothesized that measuring ramA promoter activity could act as a reporter of efflux inhibition. A rapid, inexpensive, and high-throughput green fluorescent protein (GFP) screen to identify efflux inhibitors was developed, validated, and implemented. Two chemical compound libraries were screened for compounds that increased GFP production. Fifty of the compounds in the 1,200-compound Prestwick chemical library were identified as potential efflux inhibitors, including the previously characterized efflux inhibitors mefloquine and thioridazine. There were 107 hits from a library of 47,168 proprietary compounds from L. Hoffmann La Roche; 45 were confirmed hits, and a dose response was determined. Dye efflux and accumulation assays showed that 40 Roche and three Prestwick chemical library compounds were efflux inhibitors. Most compounds had specific efflux-inhibitor-antibiotic combinations and/or species-specific synergy in antibiotic disc diffusion and checkerboard assays performed with Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, and Salmonella Typhimurium. These data indicate that both narrow-spectrum and broad-spectrum combinations of efflux inhibitors with antibiotics can be found. Eleven novel efflux inhibitor compounds potentiated antibiotic activities against at least one species of Gram-negative bacteria, and data revealing an E. coli mutant with loss of AcrB function suggested that these are AcrB inhibitors.IMPORTANCE Multidrug-resistant Gram-negative bacteria pose a serious threat to human and animal health. Molecules that inhibit multidrug efflux offer an alternative approach to resolving the challenges caused by antibiotic resistance, by potentiating the activity of old, licensed, and new antibiotics. We have developed, validated, and implemented a high-throughput screen and used it to identify efflux inhibitors from two compound libraries selected for their high chemical and pharmacological diversity. We found that the new high-throughput screen is a valuable tool to identify efflux inhibitors, as evidenced by the 43 new efflux inhibitors described in this study.

Selective and orally bioavailable phenylglycine tissue factor/factor VIIa inhibitors.

We describe the structure-based design and synthesis of highly potent, orally bioavailable tissue factor/factor VIIa inhibitors which interfere with the coagulation cascade by selective inhibition of the extrinsic pathway.