Development of a Series of Kynurenine 3-Monooxygenase Inhibitors Leading to a Clinical Candidate for the Treatment of Acute Pancreatitis

Recently, we reported a novel role for KMO in the pathogenesis of acute pancreatitis (AP). A number of inhibitors of kynurenine 3-monooxygenase (KMO) have previously been described as potential treatments for neurodegenerative conditions and particularly for Huntington’s disease. However, the inhibitors reported to date have insufficient aqueous solubility relative to their cellular potency to be compatible with the intravenous (iv) dosing route required in AP. We have identified and optimized a novel series of high affinity KMO inhibitors with favorable physicochemical properties. The leading example is exquisitely selective, has low clearance in two species, prevents lung and kidney damage in a rat model of acute pancreatitis, and is progressing into preclinical development

Mass Spectrometry Imaging for Dissecting Steroid Intracrinology within Target Tissues

Steroid concentrations within tissues are modulated by intracellular enzymes. Such “steroid intracrinology” influences hormone-dependent cancers and obesity and provides targets for pharmacological inhibition. However, no high resolution methods exist to quantify steroids within target tissues. We developed mass spectrometry imaging (MSI), combining matrix assisted laser desorption ionization with on-tissue derivatization with Girard T and Fourier transform ion cyclotron resonance mass spectrometry, to quantify substrate and product (11-dehydrocorticosterone and corticosterone) of the glucocorticoid-amplifying enzyme 11β-HSD1. Regional steroid distribution was imaged at 150–200 μm resolution in rat adrenal gland and mouse brain sections and confirmed with collision induced dissociation/liquid extraction surface analysis. In brains of mice with 11β-HSD1 deficiency or inhibition, MSI quantified changes in subregional corticosterone/11-dehydrocorticosterone ratio, distribution of inhibitor, and accumulation of the alternative 11β-HSD1 substrate, 7-ketocholesterol. MSI data correlated well with LC-MS/MS in whole brain homogenates. MSI with derivatization is a powerful new tool to investigate steroid biology within tissues