Benzene Amide Ether Scaffold is Active against Non-replicating and Intracellular Mycobacterium tuberculosis.

New drugs to treat tuberculosis which target intractable bacterial populations are required to develop shorter and more effective treatment regimens. The benzene amide ether scaffold has activity against intracellular Mycobacterium tuberculosis, but low activity against extracellular, actively replicating M. tuberculosis. We determined that these molecules have bactericidal activity against non-replicating M. tuberculosis but not actively replicating bacteria. Exposure to compounds depleted ATP levels in non-replicating bacteria and increased the oxygen consumption rate; a subset of molecules led to the accumulation of intrabacterial reactive oxygen species. A comprehensive screen of M. tuberculosis strains identified a number of under-expressing strains as more sensitive to compounds under replicating conditions including QcrA and QcrB hypomorphs. We determined the global gene expression profile after compound treatment for both replicating and nutrient-starved M. tuberculosis. We saw compound-dependent changes in the expression of genes involved in energy metabolism under both conditions. Taken together, our data suggest that the scaffold targets respiration in M. tuberculosis.

Potent, Gut-Restricted Inhibitors of Divalent Metal Transporter 1: Preclinical Efficacy against Iron Overload and Safety Evaluation.

Divalent metal transporter 1 (DMT1) cotransports ferrous iron and protons and is the primary mechanism for uptake of nonheme iron by enterocytes. Inhibitors are potentially useful as therapeutic agents to treat iron overload disorders such as hereditary hemochromatosis or ß-thalassemia intermedia, provided that inhibition can be restricted to the duodenum. We used a calcein quench assay to identify human DMT1 inhibitors. Dimeric compounds were made to generate more potent compounds with low systemic exposure. Direct block of DMT1 was confirmed by voltage clamp measurements. The lead compound, XEN602, strongly inhibits dietary nonheme iron uptake in both rats and pigs yet has negligible systemic exposure. Efficacy is maintained for >2 weeks in a rat subchronic dosing assay. Doses that lowered iron content in the spleen and liver by >50% had no effect on the tissue content of other divalent cations except for cobalt. XEN602 represents a powerful pharmacological tool for understanding the physiologic function of DMT1 in the gut. SIGNIFICANCE STATEMENT: This report introduces methodology to develop potent, gut-restricted inhibitors of divalent metal transporter 1 (DMT1) and identifies XEN602 as a suitable compound for in vivo studies. We also report novel animal models to quantify the inhibition of dietary uptake of iron in both rodents and pigs. This research shows that inhibition of DMT1 is a promising means to treat iron overload disorders.

Identification of CNS-Penetrant Aryl Sulfonamides as Isoform-Selective NaV1.6 Inhibitors with Efficacy in Mouse Models of Epilepsy.

Nonselective antagonists of voltage-gated sodium (NaV) channels have been long used for the treatment of epilepsies. The efficacy of these drugs is thought to be due to the block of sodium channels on excitatory neurons, primarily NaV1.6 and NaV1.2. However, these currently marketed drugs require high drug exposure and suffer from narrow therapeutic indices. Selective inhibition of NaV1.6, while sparing NaV1.1, is anticipated to provide a more effective and better tolerated treatment for epilepsies. In addition, block of NaV1.2 may complement the anticonvulsant activity of NaV1.6 inhibition. We discovered a novel series of aryl sulfonamides as CNS-penetrant, isoform-selective NaV1.6 inhibitors, which also displayed potent block of NaV1.2. Optimization focused on increasing selectivity over NaV1.1, improving metabolic stability, reducing active efflux, and addressing a pregnane X-receptor liability. We obtained compounds 30-32, which produced potent anticonvulsant activity in mouse seizure models, including a direct current maximal electroshock seizure assay.

Discovery of triazolone derivatives as novel, potent stearoyl-CoA desaturase-1 (SCD1) inhibitors.

Stearoyl-CoA desaturase-1 (SCD1) plays an important role in lipid metabolism. Inhibition of SCD1 activity represents a potential novel approach for the treatment of metabolic diseases such as obesity, type 2 diabetes and dyslipidemia, as well as skin diseases, acne and cancer. Herein, we report the synthesis and structure-activity relationships (SAR) of a series of novel triazolone derivatives, culminating in the identification of pyrazolyltriazolone 17a, a potent SCD1 inhibitor, which reduced plasma C16:1/C16:0 triglycerides desaturation index (DI) in an acute Lewis rat model in a dose dependent manner, with an ED50 of 4.6 mg/kg. In preliminary safety studies, compound 17a did not demonstrate adverse effects related to SCD1 inhibition after repeat dosing at 100mg/kg. Together, these data suggest that sufficient safety margins can be achieved with certain SCD1 inhibitors, thus allowing exploration of clinical utility in metabolic disease settings.

Systematic evaluation of amide bioisosteres leading to the discovery of novel and potent thiazolylimidazolidinone inhibitors of SCD1 for the treatment of metabolic diseases.

Several five- and six-membered heterocycles were introduced to replace the C2-position amide bond of the original 2-aminothiazole-based hit compound 5. Specifically, replacement of the amide bond with an imidazolidinone moiety yielded a novel and potent thiazolylimidazolidinone series of SCD1 inhibitors. XEN723 (compound 22) was identified after optimization of the thiazolylimidazolidinone series. This compound demonstrated a 560-fold improvement in in vitro potency and reduced plasma desaturation indices in a dose dependent manner, with an EC50 of 4.5 mg/kg.