# Genetically Encoded CB2R-Based Fluorescent Sensor Enables Rapid Screening and Functional Assessment of Cannabinoid Modulators

## TL;DR

Researchers developed a fluorescent sensor for the CB2R receptor to quickly test and evaluate cannabinoid drugs for their effects on inflammation and disease.

## Contribution

A new genetically encoded fluorescent sensor for CB2R enables rapid screening of cannabinoid modulators.

## Key findings

- The GRAB-CB2 sensor allows for the assessment of various cannabinoid ligands on CB2R.
- The sensor can distinguish between functionally selective and non-selective ligands.
- This tool supports the development of therapeutic agents targeting CB2R in inflammatory and neurodegenerative diseases.

## Abstract

The G-protein-coupled receptor cannabinoid receptor 2 (CB2R) initiates a key signaling pathway in mammalian physiology and pathophysiology. CB2R signaling holds significant therapeutic potential in ameliorating many pathologies, particularly in inflammatory conditions, neurodegenerative disorders, fibroproliferative and ocular diseases. CB2 modulators have been studied for their anti-inflammatory and tissue protective effects in preclinical animal models of cardiovascular, gastrointestinal, liver, kidney, lung and neurodegenerative disorders with numerous compounds undergoing clinical evaluation. Existing ligands can be classified as endocannabinoids, cannabinoid-like natural products and synthetic CB2R ligands. A genetically encoded G-protein-coupled receptor activation-based (GRAB) sensor for CB1R—GRABeCB2.0 was developed recently. This current study extends the sensor’s development to allow for a GPCR activation-based sensor for CB2R. The sensor, GRAB-CB2, will facilitate the evaluation of pharmacological characteristics and responses of various functionally selective and indiscriminate cannabinoid ligands acting on CB2.