High-Affinity Inhibitors of Human NAD+-Dependent 15-Hydroxyprostaglandin Dehydrogenase: Mechanisms of Inhibition and Structure-Activity Relationships

Abstract

Background15-hydroxyprostaglandin dehydrogenase (15-PGDH, EC 1.1.1.141) is the key enzyme for the inactivation of prostaglandins, regulating processes such as inflammation or proliferation. The anabolic pathways of prostaglandins, especially with respect to regulation of the cyclooxygenase (COX) enzymes have been studied in detail; however, little is known about downstream events including functional interaction of prostaglandin-processing and -metabolizing enzymes. High-affinity probes for 15-PGDH will, therefore, represent important tools for further studies.Principal FindingsTo identify novel high-affinity inhibitors of 15-PGDH we performed a quantitative high-throughput screen (qHTS) by testing >160 thousand compounds in a concentration-response format and identified compounds that act as noncompetitive inhibitors as well as a competitive inhibitor, with nanomolar affinity. Both types of inhibitors caused strong thermal stabilization of the enzyme, with cofactor dependencies correlating with their mechanism of action. We solved the structure of human 15-PGDH and explored the binding modes of the inhibitors to the enzyme in silico. We found binding modes that are consistent with the observed mechanisms of action.ConclusionsLow cross-reactivity in screens of over 320 targets, including three other human dehydrogenases/reductases, suggest selectivity of the present inhibitors for 15-PGDH. The high potencies and different mechanisms of action of these chemotypes make them a useful set of complementary chemical probes for functional studies of prostaglandin-signaling pathways.Enhanced version This article can also be viewed as an enhanced version in which the text of the article is integrated with interactive 3D representations and animated transitions. Please note that a web plugin is required to access this enhanced functionality. Instructions for the installation and use of the web plugin are available in Text S2.

Effects of Levosimendan on Cardiac Gene Expression Profile and Post-Infarct Cardiac Remodelling in Diabetic Goto-Kakizaki Rats

“…We showed here that levosimendan down‐regulated the Hpgd gene in GK MI rats. The Hpgd gene encodes the NAD + ‐dependent 15‐dehydroprostaglandin dehydrogenase enzyme [15‐prostaglandin dehydrogenase (PGDH)], one of the main inactivators of prostaglandins [23]. Interestingly, PPAR‐gamma agonists used in the management of diabetes, including ciglitazone and pioglitazone, have been shown to inhibit 15‐PGDH [24].…”

Recent developments in the use of differential scanning fluorometry in protein and small molecule discovery and characterization

“…A screen of ~160,000 compounds in a concentration-response format identified novel inhibitors of 15-PGDH that act as noncompetitive inhibitors (denoted compounds 13 and 72) as well as a competitive inhibitor (denoted compound 61), with nanomolar affinity [63]. The 15-PGDH reaction follows several steps of engagement and disengagement of substrate, cofactors, and products, generally described as an ordered bi-bi mechanism.…”

Structure–activity relationship studies and biological characterization of human NAD+-dependent 15-hydroxyprostaglandin dehydrogenase inhibitors

“…1). 15 The first scaffold, ML147 , is characterized by an azabenzimidazole core appended with a thiobenzyl group at C-1. The second compound, ML148 possesses a benzimidazole core substituted with a cyclohexylamide moiety and 3-methyl-phenyl group.…”