Diacylglycerol lipaseα-dependent endocannabinoid signaling in neural stem cells

    Student thesis: Doctoral ThesisDoctor of Philosophy


    The diacylglycerol lipases (DAGL α and β) synthesise 2-AG, the major endocannabinoid (eCB) in the developing and adult brain. 2-AG acts most prominently on the CB1 and CB2 receptors and growing evidence points to a role of eCB signaling in adult neurogenesis as well as a wide range of different physiological roles in the brain. The focus of this thesis is on DAGL driven eCB signaling in neural stem cells (NSC). A role of the eCB system has previously been established in migration, proliferation, and neurogenesis. Here we investigated DAGLα and eCB signaling in the context of differentiation.
    The Cor-1 cells were adapted as a NSC model system and can be differentiated into glia and neurons. This differentiation was unaffected by CB signaling. While DAGLα expression is unaffected by glial differentiation, a rapid down regulation of DAGLα during neuronal differentiation was detected and we investigated the possibility of a specific degradation pathway being involved. DAGLα has a consensus motif for a putative destruction (d-) box that might target DAGL for ubiquitin-proteasome mediated degradation. No evidence was found to support that the d-box is involved in DAGLα degradation, however first indications towards degradation through the ubiquitin-proteasome pathway were identified.
    What is upstream of eCB signaling in NSCs remains an open question. The most likely candidates are EGF, FGF-2 and insulin and their effect on eCB signaling was investigated. Evidence was found indicating that neither EGF nor FGFR signaling is upstream of eCB signaling in Cor-1 cells. Microarray analysis indicates a potential common signaling node between EGFR and eCB signaling. mTOR was investigated in this context, but while we show that mTOR appears to be downstream the EGFR, no indication was found that it is downstream of the eCB receptors. Further experiments are needed to determine the relationship between insulin and eCB signaling. It is essential to be able to measure DAGL activity, and a surrogate substrate DAGL activity assay was adapted to Cor-1 cells in order to address what is driving eCB signaling.
    Date of Award9 Oct 2012
    Original languageEnglish
    Awarding Institution
    • King's College London
    SupervisorPatrick Doherty (Supervisor) & Gareth Williams (Supervisor)

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