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AbstractContext:There is an ongoing search for specific and translational biomarkers of drug-induced liver injury (DILI). MicroRNA-122 (miR-122) has previously shown potential as a sensitive, specific, and translational biomarker of DILI in both rodent, and human studies.Objective:To build on previous work within the field, we examined biomarker kinetics in a rat model of acetaminophen (APAP)-induced liver injury to confirm the sensitivity, and specificity of miR-122 and glutamate dehydrogenase (GLDH).Materials and methods:qRT-PCR and a standard enzymatic assay were used for biomarker analysis.Results:Both miR-122 and GLDH were demonstrated to be more readily-detectable biomarkers of APAP-DILI than alanine aminotransferase (ALT). Peak levels for all biomarkers were detected at 2 days after APAP. At day 3, miR-122 had returned to baseline; however, other biomarkers remained elevated between 3 and 4 days. We were also able to demonstrate that, although miR-122 is present in greater quantities in exosome-free form, both exosome-bound and non-vesicle bound miR-122 are released in a similar profile throughout the course of DILI.Discussion and conclusions:Together, this study demonstrates that both GLDH and miR-122 could be used during preclinical drug-development as complementary biomarkers to ALT to increase the chance of early detection of hepatotoxicity.

We have developed compounds with a promising activity against Acinetobacter baumanniiand Pseudomonas aeruginosa, which are both on the WHO priority list of antibiotic-resistant bacteria. Starting from DNA gyrase inhibitor 1, we identified compound 27, featuring a 10-fold improved aqueous solubility, a 10-fold improved inhibition of topoisomerase IV from A. baumanniiand P. aeruginosa, a 10-fold decreased inhibition of human topoisomerase IIα, and no cross-resistance to novobiocin. Cocrystal structures of 1in complex with Escherichia coliGyrB24 and (S)-27in complex with A. baumanniiGyrB23 and P. aeruginosaGyrB24 revealed their binding to the ATP-binding pocket of the GyrB subunit. In further optimization steps, solubility, plasma free fraction, and other ADME properties of 27were improved by fine-tuning of lipophilicity. In particular, analogs of 27with retained anti-Gram-negative activity and improved plasma free fraction were identified. The series was found to be nongenotoxic, nonmutagenic, devoid of mitochondrial toxicity, and possessed no ion channel liabilities.

A new series of dual low nanomolar benzothiazole inhibitors of bacterial DNA gyrase and topoisomerase IV were developed. The resulting compounds show excellent broad-spectrum antibacterial activities against Gram-positive Enterococcus faecalis, Enterococcus faeciumand multidrug resistant (MDR) Staphylococcus aureusstrains [best compound minimal inhibitory concentrations (MICs): range, <0.03125–0.25 μg/mL] and against the Gram-negatives Acinetobacter baumanniiand Klebsiella pneumoniae(best compound MICs: range, 1–4 μg/mL). Lead compound 7awas identified with favorable solubility and plasma protein binding, good metabolic stability, selectivity for bacterial topoisomerases, and no toxicity issues. The crystal structure of 7ain complex with Pseudomonas aeruginosaGyrB24 revealed its binding mode at the ATP-binding site. Expanded profiling of 7aand 7hshowed potent antibacterial activity against over 100 MDR and non-MDR strains of A. baumanniiand several other Gram-positive and Gram-negative strains. Ultimately, in vivo efficacy of 7ain a mouse model of vancomycin-intermediate S. aureusthigh infection was also demonstrated.

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Ximelagatran was developed for the prevention and treatment of thromboembolic conditions. However, in long-term clinical trials with ximelagatran, the liver injury marker, alanine aminotransferase (ALT) increased in some patients. Analysis of plasma samples from 134 patients was carried out using proteomic and metabolomic platforms, with the aim of finding predictive biomarkers to explain the ALT elevation. Analytes that were changed after ximelagatran treatment included 3-hydroxybutyrate, pyruvic acid, CSF1R, Gc-globulin, L-glutamine, protein S and alanine, etc. Two of these analytes (pyruvic acid and CSF1R) were studied further in human cell cultures in vitrowith ximelagatran. A systems biology approach applied in this study proved to be successful in generating new hypotheses for an unknown mechanism of toxicity.