Deficiency of Inositol Monophosphatase Activity Decreases Phosphoinositide Lipids and Enhances TRPV1 Function In Vivo

• Published in: The Journal of neuroscience Vol. 41; no. 3; pp. 408 - 423
• Main Authors: Caires, Rebeca, Bell, Briar, Lee, Jungsoo, Romero, Luis O, Vásquez, Valeria, Cordero-Morales, Julio F
• Format: Journal Article
• Language: English
• Published: United States Society for Neuroscience 20.01.2021
• Subjects: Animals; Behavior, Animal; Caenorhabditis elegans - physiology; Caenorhabditis elegans Proteins - biosynthesis; Calcium Signaling - drug effects; Capsaicin; Capsaicin - pharmacology; Capsaicin receptors; Diet; Dietary Supplements; Domains; HEK293 Cells; Humans; Hypersensitivity; In vivo methods and tests; Inflammation; Ion channels; Lipid Metabolism; Lipids; myo-Inositol-1 (or 4)-monophosphatase; Neurons - metabolism; Pain; Pain perception; Phosphatidylinositols - metabolism; Phosphatidylinositols - pharmacology; Phospholipase C; Phosphoric Monoester Hydrolases - deficiency; Potentiation; Receptors; Transient receptor potential proteins; TRPV Cation Channels - genetics; TRPV Cation Channels - physiology; Caenorhabditis elegans; in vivo calcium imaging; TRPV1; inositol monophosphatase; lipid regulation; phosphoinositides
• ISSN: 0270-6474; 1529-2401
• DOI: 10.1523/JNEUROSCI.0803-20.2020

Membrane remodeling by inflammatory mediators influences the function of sensory ion channels. The capsaicin- and heat-activated transient receptor potential vanilloid 1 (TRPV1) channel contributes to neurogenic inflammation and pain hypersensitivity, in part because of its potentiation downstream of phospholipase C-coupled receptors that regulate phosphoinositide lipid content. Here, we determined the effect of phosphoinositide lipids on TRPV1 function by combining genetic dissection, diet supplementation, and behavioral, biochemical, and functional analyses in As capsaicin elicits heat and pain sensations in mammals, transgenic TRPV1 worms exhibit an aversive response to capsaicin. TRPV1 worms with low levels of phosphoinositide lipids display an enhanced response to capsaicin, whereas phosphoinositide lipid supplementation reduces TRPV1-mediated responses. A worm carrying a TRPV1 construct lacking the distal C-terminal domain features an enhanced response to capsaicin, independent of the phosphoinositide lipid content. Our results demonstrate that TRPV1 activity is enhanced when the phosphoinositide lipid content is reduced, and the C-terminal domain is key to determining agonist response .