Patent highlights June-July 2020

摘要

Nicotinamide dinucleotide (NAD) can be synthesized via de novo production from tryptophan, but mammalian cells mainly rely on salvage pathways that recycle the nicotinamide generated by NAD-consuming enzymes. Nmnat, a stress response enzyme which exists in three differentially localized isoforms [1], produces NAD from nicotinamide mononucleotide and acts in all three salvage pathways and the de novo pathway. Nmnat enzymes are essential neuronal maintenance factors, probably by an additional chaperone activity [2]. Overexpression of Nmnat2 (the isoform in the Golgi apparatus) also seems to protect against cardiac hypertrophy [3] and colon cancer [4]. The inventors' novel semicarbazones and thiosemicarbazones are supposed to be the first reported nongenetic activators of Nmnat2. About 50,000 synthetic organic chemicals were tested in a doubly coupled high-throughput assay that contained two enzymes, Nmnat2 and alcohol dehydrogenase (to convert NAD into the fluorescent indicator product). Compounds exhibiting activating properties were retested in an alcohol dehydrogenase assay that used NAD as a substrate; those that were inactive in this secondary assay might represent direct activators of Nmnat2. The preferred compound is (E)-N'-(1- (pyridin-2-yl) ethylidene) azetidine-1-carbothiohydrazide; in the murine chemotherapy-induced peripheral neuropathy paradigm it significantly increased the paw pressure threshold at a dose of 10 or 3 (but not 1) mg/kg/day i.p.