Decrypting nociceptive signaling pathways in Caenorhabditis elegans using behavioral analysis and mass spectrometry-based proteomics

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My NSERC Discovery research program is dedicated to understanding the molecular processes associated with nociceptive behaviors, the neurochemistry of synaptic transmission and identify targets that can regulate nociceptive processing. The overall goal of this proposal will be to 1) characterize the effects of endocannabinoids and cannabinoids on nocifensive response of Caenorhabditis elegans (C. elegans) to noxious heat and compared with vanilloids, 2) characterize the interplay between cannabinoid and vanilloid systems using specific C. elegans mutants, pharmacological manipulations and proteomics; 3) identify the molecular target of endocannabinoids, cannabinoids and vanilloids in C. elegans using a variant of the thermal shift assays used to study thermal stabilization of proteins upon ligand binding combined with an unbiased, proteome-wide approach for the identification of specific-binding protein targets. C. elegans is a powerful experimental model system relevant to mammalian physiology. C. elegans consists of 959 cells, of which 302 are neurons, which makes this model attractive to study nociception, the sensory nervous system's responsible for triggering a response to harmful stimuli. Nociceptors are sensory receptors specialized in detecting potential harm, including temperature, mechanical, and chemical. Transient receptor potential (TRP) channels are essential detectors and transducers of harmful stimuli. C. elegans genome encodes several TRP channels including transient receptor potential cation channel subfamily V (TRPV or vanilloid receptor) orthologs (OSM-9 and OCR1-4). It has been recently established that C. elegans TRP channels are associated with behavioral and physiological processes, including sensory transduction. Many C. elegans TRP channels share similar activation and regulatory mechanisms with their vertebrate counterparts. The endocannabinoid system is involved in modulation of nociception and recent evidence suggests interactions with the vanilloid systems. Many studies identified components of a C. elegans endocannabinoid system including numerous endocannabinoid ligands. Thus, we believe that C. elegans expresses receptors that act as functional homologs of mammalian cannabinoid receptors and is an ideal experimental model to study new cannabinoid signaling pathways and their interplay with the vanilloid systems. In addition to the two main cannabinoid receptors (CB1 and CB2), there is growing evidence that there are other, not yet identified, cannabinoid receptors in mammals. This research proposal will have a significant impact on the production of knowledge fundamental to characterize heat activated signaling pathways mediated by vanilloid receptors and their interaction(s) with the cannabinoid system components. This is a fundamental step to ensure translational success of experimental models. Moreover, this comprehensive study may lead to the discovery of a novel cannabinoid receptor.