The fibrate gemfibrozil is a NO‐ and haem‐independent activator of soluble guanylyl cyclase: in vitro studies

• Published in: British journal of pharmacology Vol. 172; no. 9; pp. 2316 - 2329
• Main Authors: Sharina, I G, Sobolevsky, M, Papakyriakou, A, Rukoyatkina, N, Spyroulias, G A, Gambaryan, S, Martin, E
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01-05-2015; BlackWell Publishing Ltd
• Subjects: Animals; Aorta, Thoracic - drug effects; Aorta, Thoracic - enzymology; Binding Sites; Dose-Response Relationship, Drug; Drug therapy; Enzyme Activation; Enzyme Activators - pharmacology; Gemfibrozil - pharmacology; Guanylate Cyclase - metabolism; Heme - metabolism; Humans; Hypolipidemic Agents - pharmacology; Lipids; Male; Molecular Docking Simulation; Nitric Oxide - metabolism; Oxidation-Reduction; Platelet Aggregation - drug effects; Platelet Aggregation Inhibitors - pharmacology; Protein Structure, Tertiary; Rats, Sprague-Dawley; Receptors, Cytoplasmic and Nuclear - metabolism; Recombinant Proteins - metabolism; Research Papers; Signal Transduction - drug effects; Soluble Guanylyl Cyclase; Time Factors; Vasodilation - drug effects; Vasodilator Agents - pharmacology
• ISSN: 0007-1188; 1476-5381
• DOI: 10.1111/bph.13055

Background and Purpose
Fibrates are a class of drugs widely used to treat dyslipidaemias. They regulate lipid metabolism and act as PPARα agonists. Clinical trials demonstrate that besides changes in lipid profiles, fibrates decrease the incidence of cardiovascular events, with gemfibrozil exhibiting the most pronounced benefit. This study aims to characterize the effect of gemfibrozil on the activity and function of soluble guanylyl cyclase (sGC), the key mediator of NO signalling.
Experimental Approach
High‐throughput screening of a drug library identified gemfibrozil as a direct sGC activator. Activation of sGC is unique to gemfibrozil and is not shared by other fibrates.
Key Results
Gemfibrozil activated purified sGC, induced endothelium‐independent relaxation of aortic rings and inhibited platelet aggregation. Gemfibrozil‐dependent activation was absent when the sGC haem domain was deleted, but was significantly enhanced when sGC haem was lacking or oxidized. Oxidation of sGC haem enhanced the vasoactive and anti‐platelet effects of gemfibrozil. Gemfibrozil competed with the haem‐independent sGC activators ataciguat and cinaciguat. Computational modelling predicted that gemfibrozil occupies the space of the haem group and interacts with residues crucial for haem stabilization. This is consistent with structure‐activity data which revealed an absolute requirement for gemfibrozil's carboxyl group.
Conclusions and Implications
These data suggest that in addition to altered lipid and lipoprotein state, the cardiovascular preventive benefits of gemfibrozil may derive from direct activation and protection of sGC function. A sGC‐directed action may explain the more pronounced cardiovascular benefit of gemfibrozil observed over other fibrates and some of the described side effects of gemfibrozil.