GRAB SENSORS AS TOOLS TO ELUCIDATE MOLECULAR DYNAMICS OF THE GLIAL PURINERGIC AND ENDOCANNABINOID SYSTEMS IN FAAH-DEFICIENT MODELS

The endocannabinoid system (ECS) acts as a vital neuromodulator within the central nervous system, regulating neuroprotection, cognition, and inflammatory responses. Given its role in these processes, the ECS has emerged as a promising pharmacological target for neurodegenerative disorders. In Alzheimer’s Disease (AD), increasing endogenous endocannabinoid levels—specifically by targeting fatty acid amide hydrolase (FAAH), the enzyme that degrades AEA—offers a putative therapeutic strategy. Research in AD mouse models indicates that FAAH inactivation elevates AEA levels and alters neuroinflammatory profiles, resulting in reduced beta-amyloid deposition, improved synaptic plasticity, and preserved memory. While glial cells like astrocytes and microglia appear to drive these neuroprotective effects, the precise molecular mechanisms remain to be fully characterized.
To investigate these pathways, we utilized G protein-coupled receptor activation-based (GRAB) sensors to monitor the real-time dynamics of the endocannabinoids AEA and 2-AG, alongside ATP, all of which are central to glial function. We developed and optimized viral vectors for these fluorescent biosensors and validated their performance in vitro using the GL261 glioma cell line and primary astrocyte cultures from both wild-type (WT) and FAAH-knockout (FAAH-/-) mice. These preliminary findings establish a critical foundation for upcoming in vivo studies, which will employ viral delivery in live mice to track the real-time interplay between the purinergic and endocannabinoid systems in the context of AD pathology.