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Show THE UNIVERSITY OF UTAH HONORS COLLEGE ACTIVATION OF TRANSIENT RECEPTOR POTENTIAL ANKYRIN-1 BY W O OD SMOKE PARTICULATE MATERIAL Darien Shapiro (Christopher A. Reilly) Department of Pharmacology and Toxicology University of Utah Exposure to wood smoke particulate matter (WSPM) has recently been linked to exacerbation of pre-existing respiratory conditions such as asthma, development of chronic obstructive pulmonary disease (COPD), and premature deaths. While it is clear that W S P M exposure is hazardous to human health, the specific molecular basis through which it causes these adverse respiratory effects is not well understood. Transient receptor potential ankyrin-1 (TRPA1) is a cation channel that is expressed in sensory neurons, small airway epithelial cells, smooth muscle cells, and fibroblasts, and has recently been implicated as a mediator of P M toxicity for several combustion-derived particulate materials (cdPM), including diesel exhaust (DEP) and cigarette smoke (CS). The hypothesis of this project was that W S P M would selectively activate TRPA1 through direct binding of receptor active sites, electrophilic modification, and/or mechanical contact, which would then initiate cellular processes that culminate in pulmonary inflammation, lung injury, and respiratory dysfunction. Pine and mesquite P M were generated in the laboratory and activated TRPA1 in a manner similar to DEP and CS in all cell lines tested; TRPA1 over-expressing HEK-293, primary mouse trigeminal (TG) neurons, and human alveolar adenocarcinoma (A549) cells. TRPA1 activation by W S P M was attenuated by a TRPA1 antagonist, HC-030031, in both A459 cells and TG neurons. Differential activation of TRPA1, as a function of particle size, demonstrated that PM<2.5 p m were most potent. Additionally, several known chemical components of W S P M were TRPA1 agonists. Both W S P M and agathic acid activated TRPA1 primarily though the electophile/ oxidant sensing site, while 3,5-ditert-butyl-phenol activated TRPA1 through the menthol-binding site. This study establishes W S P M as a potent and selective activator of TRPA1 and outlines the specific biochemical mechanisms by which W S P M and associated chemical components activate TRPA1. These results provide key mechanistic insights into h o w one can develop therapeutics for W S P M toxicity in the respiratory tract. Support: NIEHS ES017431 and the University of Utah Undergraduate Research Opportunities Program. |
