Scientists Developed the First Drugs That Specifically Block Endocannabinoid Production | Research

The takeaway

Researchers identified the first potent and selective inhibitors of DAGL, the enzyme that produces the endocannabinoid 2-AG, creating new pharmacological tools for studying the endocannabinoid system's biological roles.

Read this if you are interested in the molecular biology of the endocannabinoid system and how researchers develop tools to study it.

First selective DAGL-alpha inhibitors achieved IC50 of 160 nM with high selectivity over related enzymes

What the researchers found

Researchers developed and screened new synthetic compounds as inhibitors of DAGL-alpha, the enzyme responsible for producing the endocannabinoid 2-arachidonoyl glycerol (2-AG). They also tested for inhibitors of MAGL, the enzyme that breaks down 2-AG.

The most potent and selective DAGL-alpha inhibitors were compounds O-3640 (IC50 = 500 nM) and O-3841 (IC50 = 160 nM). These compounds were highly selective: they were nearly inactive against MAGL, rat liver lipase, the anandamide synthesis enzyme, FAAH, and cannabinoid CB1 and CB2 receptors.

Additional compounds were identified that inhibited both DAGL-alpha and MAGL with similar potency, providing different pharmacological tools for studying endocannabinoid biology.

Why it matters

Before this work, researchers could boost endocannabinoid signaling by blocking degradation, but could not specifically reduce 2-AG production. These selective DAGL inhibitors provided the first tools to study what happens when endocannabinoid synthesis is blocked, fundamental to understanding the system's biological roles.

The numbers in context

O-3640 IC50: 500 nM against DAGL-alpha. O-3841 IC50: 160 nM against DAGL-alpha. Both nearly inactive on MAGL, liver lipase, NAPE-PLD, FAAH, CB1, and CB2. Reference compound orlistat: IC50 approximately 60 nM but non-selective.

How the study worked

In vitro enzyme inhibition study using membranes from COS cells over-expressing recombinant human DAGL-alpha and cytosolic fractions from wild-type COS cells for MAGL. Screened known compounds and new phosphonate derivatives of oleic acid and fluoro-phosphinoyl esters. Selectivity tested against multiple related enzymes and receptors.

What this study cannot tell us

All testing was in vitro using recombinant enzymes, not in living animals or humans. The selectivity profile was tested against a limited panel of related enzymes. The compounds may behave differently in biological systems where additional factors affect drug availability and metabolism.

How to read the evidence

In vitro pharmacology study developing research tools. Important for the field but no direct therapeutic or clinical implications.

When this study was published

Published in 2006. DAGL inhibitors have since been used extensively as research tools and the understanding of 2-AG biology has expanded.

The bigger picture

Developing selective pharmacological tools is essential for understanding any biological system. These DAGL inhibitors allowed researchers to test whether blocking 2-AG production at specific sites would affect pain, inflammation, appetite, and other processes regulated by the endocannabinoid system.

Questions still open

Do these DAGL inhibitors produce measurable effects when administered to animals? Could DAGL inhibition be a therapeutic strategy for conditions where endocannabinoid overactivity is problematic?

Common questions

Why does blocking endocannabinoid production matter?

The body constantly produces and breaks down endocannabinoids. Being able to specifically block production of 2-AG (one of the two main endocannabinoids) lets researchers understand what happens when this signaling is reduced, which could inform treatment for conditions involving overactive endocannabinoid signaling.

Could these drugs be used as medicines?

This study developed research tools, not medicines. The compounds were tested only in test tubes with purified enzymes. Whether blocking 2-AG production could be therapeutically useful requires extensive further research, including animal and eventually human studies.

Read the original research

Development of the first potent and specific inhibitors of endocannabinoid biosynthesis.

Biochimica et biophysica acta, 1761(2), 205-12

View on PubMed ↗

Citation

Bisogno, Tiziana; Cascio, Maria Grazia; Saha, Bijali; Mahadevan, Anu; Urbani, Paolo; Minassi, Alberto; Appendino, Giovanni; Saturnino, Carmela; Martin, Billy; Razdan, Raj; Di Marzo, Vincenzo. (2006). Development of the first potent and specific inhibitors of endocannabinoid biosynthesis.. Biochimica et biophysica acta, 1761(2), 205-12.