Acknowledgments br INTRODUCTION AND OBJECTIVES br METHODS br

Acknowledgments
INTRODUCTION AND OBJECTIVES
METHODS
RESULTS
CONCLUSIONS
Introduction Class 3 alcohol dehydrogenase (EC 1.1.1.1), also known as ADH5 chi polypeptide in humans, was first identified by Koivusalo et al. [1] as a NAD+-dependent hydroxymethylglutathione (HMGSH) oxidase. By metabolizing HMGSH, the spontaneous adduct formed between formaldehyde and glutathione, class 3 alcohol dehydrogenase was noted as an important component in formaldehyde detoxification. A few years later, Jensen and Liu [2], [3] discovered that in addition to activity towards HMGSH, class 3 alcohol dehydrogenase can specifically and efficiently catalyze the NADH-dependent reduction of S-nitrosoglutathione (GSNO) to hydroxylamine. As a result, this enzyme was renamed GSNO reductase (GSNOR) by researchers in the S-nitrosothiol (SNO) signaling field. GSNO is an endogenous SNO and a source of bioavailable nitric oxide (NO). This low molecular weight SNO can modulate protein S-nitrosation via transnitrosation. By metabolizing GSNO, GSNOR activity indirectly promotes protein denitrosation. It is interesting to note that GSNOR is not unique in its ability to metabolize GSNO. Other enzymes, including super oxide dismutase [4], glutathione peroxidase [5], protein disulfide isomerase [6], thioredoxin [7], and carbonyl reductase [8] have all been shown to metabolize GSNO. Of these enzymes, only GSNOR and carbonyl reductase are capable of irreversibly removing the NO equivalents stored in GSNO. However, only thioredoxin and GSNOR have been demonstrated to function in a physiological context [9]. Research has demonstrated pivotal roles for GSNOR related to cardiovascular and respiratory health and disease. For example, mice deficient in GSNOR are protected from experimentally induced sigma receptor [10] and show cardioprotection with myocardial infarction [11]. GSNOR is linked to asthmatic responsiveness in humans [12] with single nucleotide polymorphisms influencing responsiveness to bronchodilators [13], [14], [15]. GSNOR is also implicated in vasculogenesis [16], lung cancer [17], maturation of the cystic fibrosis transmembrane regulator (CFTR) [18] and bronchopulmonary dysplasia [19]. The involvement of GSNOR in these significant heart- and lung-related pathologies has made it a potential therapeutic target for the development of GSNOR-specific inhibitors to modulate intracellular S-nitrosothiol levels [20], [21]. In this study, we introduce O-aminobenzoyl-S-nitrosoglutathione (OAbz-GSNO), a fluorogenic pseudo-substrate for GSNOR. The characterization of OAbz-GSNO includes in vitro catalytic properties, cell permeability and usefulness in monitoring GSNOR activity in live, primary mouse lung endothelial cells.
Results and discussion
Materials
Methods
Funding sources This research is supported by Natural Sciences and Engineering Research Council (NSERC) Canada Discovery Grant to B.M. and Project 2 of Program Project Grant [PO1HL101871] to L.A.P.
Conflict of interest disclosure
Acknowledgements
Endogenous -nitrosothiols (SNOs) are important conductors of the biological influence of nitric oxide, from bronchodilation and vasodilation to controlling inflammation., , -Nitrosoglutathione reductase (GSNOR), also known as the human ADH class III enzyme and formaldehyde dehydrogenase,, catalyzes the metabolism of the most abundant low molecular weight SNO, -nitrosoglutathione (GSNO),, and has been identified as a potential drug target for the treatment of a broad range of diseases., , , , , The therapeutic potential of GSNOR inhibitors has been demonstrated in animal models of asthma,, , chronic obstructive pulmonary disease (COPD), inflammatory bowel disease (IBD) and high salt induced hypertension. We have recently reported the identification of as a potent -nitrosoglutathione reductase inhibitor in clinical development, for the treatment of acute asthma, and extended these observations with a report on structure–activity relationship of GSNOR inhibitors based on a pyrrole scaffold. As a continuation of the series communication of the pyrrole based GSNOR inhibitors, we report here the studies to further improve the overall pharmacological properties of GSNOR inhibitors, focusing on the substitution of the imidazole moiety and replacement of this moiety with a variety of heterocycles in an attempt to eliminate the cytochrome P450 inhibitory activities previously reported GSNOR inhibitors.