Simplified assays of lipolysis enzymes for drug discovery and specificity assessment of known inhibitors

• Published in: Journal of lipid research 2016-01, Vol.57 (1), p.131-141
• Main Authors: Iglesias, Jose, Lamontagne, Julien, Erb, Heidi, Gezzar, Sari, Zhao, Shangang, Joly, Erik, Truong, Vouy Linh, Skorey, Kathryn, Crane, Sheldon, Madiraju, S.R.Murthy, Prentki, Marc
• Format: Article
• Language: English
• Subjects: Adipose Tissue - metabolism; adipose triglyceride lipase; alpha/beta hydrolase domain 6; Animals; Carboxylic Ester Hydrolases - antagonists & inhibitors; Carboxylic Ester Hydrolases - metabolism; diacylglycerol lipase; Drug Discovery - methods; Enzyme Inhibitors - pharmacology; fatty acid amide hydrolase; Fatty Acids - metabolism; hormone sensitive lipase; Humans; Lipase - antagonists & inhibitors; Lipase - metabolism; Lipogenesis - physiology; Lipolysis - drug effects; Lipolysis - physiology; Lipoprotein Lipase - antagonists & inhibitors; Lipoprotein Lipase - metabolism; Methods; Mice; monoacylglycerol lipase; Monoacylglycerol Lipases - metabolism; Sterol Esterase - antagonists & inhibitors; Sterol Esterase - metabolism; Triglycerides - metabolism
• ISSN: 0022-2275; 1539-7262
• DOI: 10.1194/jlr.D058438

Lipids are used as cellular building blocks and condensed energy stores and also act as signaling molecules. The glycerolipid/ fatty acid cycle, encompassing lipolysis and lipogenesis, generates many lipid signals. Reliable procedures are not available for measuring activities of several lipolytic enzymes for the purposes of drug screening, and this resulted in questionable selectivity of various known lipase inhibitors. We now describe simple assays for lipolytic enzymes, including adipose triglyceride lipase (ATGL), hormone sensitive lipase (HSL), sn-1-diacylglycerol lipase (DAGL), monoacylglycerol lipase, α/β-hydrolase domain 6, and carboxylesterase 1 (CES1) using recombinant human and mouse enzymes either in cell extracts or using purified enzymes. We observed that many of the reported inhibitors lack specificity. Thus, Cay10499 (HSL inhibitor) and RHC20867 (DAGL inhibitor) also inhibit other lipases. Marked differences in the inhibitor sensitivities of human ATGL and HSL compared with the corresponding mouse enzymes was noticed. Thus, ATGListatin inhibited mouse ATGL but not human ATGL, and the HSL inhibitors WWL11 and Compound 13f were effective against mouse enzyme but much less potent against human enzyme. Many of these lipase inhibitors also inhibited human CES1. Results describe reliable assays for measuring lipase activities that are amenable for drug screening and also caution about the specificity of the many earlier described lipase inhibitors.