Investigating the role of cannabinoid receptors in oligodendrocyte development

Project Summary Myelin is the protective sheath that wraps around neuronal axons to facilitate fast, saltatory conduction, maintain axon integrity, and provide metabolic support. It is made by specialized glial cells called oligodendrocytes (OL) in the central nervous system (CNS). The importance of myelin is highlighted in neurological diseases such as multiple sclerosis (MS), where disruption of myelin can result in improper neuronal function and may ultimately lead to axonal degeneration along with other symptoms. While the importance of myelin is thus evident, there are currently no treatment options to prevent or aid in remyelination, in part because the molecular mechanisms of myelin formation are not fully understood. However, the endocannabinoid system (ECS) has gained increasing interest as a potential target to treat several neurological diseases, including MS. Yet there is no clear understanding in the relationship between the ECS and OL development or myelination. Aiming to understand of the molecular mechanisms that drive OL development and myelination, our lab conducted a proteomic analysis of cultured rat primary OLs in which myelination was increased by genetic methods. Among the list of proteins that were significantly upregulated in OLs with increased myelin were two ECS enzymes, FAAH1 and DAGL-. This increase occurred during OL precursor (OPC) differentiation, suggesting the ECS may play a role at this stage of OL development. This model is supported by my preliminary in vivo studies in zebrafish activating the ECS. For this proposal, I aim to define the role of CB1 and CB2 in OL development and myelination through continued pharmacological receptor manipulation, careful genomic analysis using CRISPR-Cas9 mediated genome editing, and precise multidimensional receptor activation and live imaging. In Aim 1, I will use a range of pharmacological and genetic approaches to dissect the roles of CB1 and CB2 in various stages of OL development and myelination. In Aim 2, I will investigate the downstream signaling effects of CB1 activation through calcium imaging, using a novel photocaged ligand that is genetically targeted to OL lineage cells.