Activation of the chemosensing transient receptor potential channel A1 (TRPA1) by alkylating agents.
The transient receptor potential ankyrin 1 (TRPA1) cation channel is expressed in different tissues including skin, lung and neuronal tissue. Recent reports identified TRPA1 as a sensor for noxious substances, implicating a functional role in the molecular toxicology. TRPA1 is activated by various potentially harmful electrophilic substances. The chemical warfare agent sulfur mustard (SM) is a highly reactive alkylating agent that binds to numerous biological targets. Although SM is known for almost 200 years, detailed knowledge about the pathophysiology resulting from exposure is lacking. A specific therapy is not available. In this study, we investigated whether the alkylating agent 2-chloroethyl-ethylsulfide (CEES, a model substance for SM-promoted effects) and SM are able to activate TRPA1 channels. CEES induced a marked increase in the intracellular calcium concentration ([Ca(2+)]i) in TRPA1-expressing but not in TRPA1-negative cells. The TRP-channel blocker AP18 diminished the CEES-induced calcium influx. HEK293 cells permanently expressing TRPA1 were more sensitive toward cytotoxic effects of CEES compared with wild-type cells. At low CEES concentrations, CEES-induced cytotoxicity was prevented by AP18. Proof-of-concept experiments using SM resulted in a pronounced increase in [Ca(2+)]i in HEK293-A1-E cells. Human A549 lung epithelial cells, which express TRPA1 endogenously, reacted with a transient calcium influx in response to CEES exposure. The CEES-dependent calcium response was diminished by AP18. In summary, our results demonstrate that alkylating agents are able to activate TRPA1. Inhibition of TRPA1 counteracted cellular toxicity and could thus represent a feasible approach to mitigate SM-induced cell damage.
Walther-Straub-Institute of Pharmacology and Toxicology, Ludwig-Maximilian-University Munich, Goethestraße 33, 80336, Munich, Germany.
Bernhard
B
Stenger
Franziska
F
Zehfuss
Harald
H
Mückter
Annette
A
Schmidt
Frank
F
Balszuweit
Eva
E
Schäfer
Thomas
T
Büch
Thomas
T
Gudermann
Horst
H
Thiermann
Dirk
D
Steinritz
D000477:Alkylating Agents / Q000633:toxicity*; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000187:drug effects* / Q000378:metabolism; D002460:Cell Line; D002619:Chemical Warfare Agents / Q000633:toxicity*; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D008168:Lung / Q000166:cytology / Q000187:drug effects; D009151:Mustard Gas / Q000031:analogs & derivatives* / Q000633:toxicity; D009419:Nerve Tissue Proteins / Q000187:drug effects* / Q000378:metabolism; D010091:Oximes / Q000494:pharmacology; D000074025:TRPA1 Cation Channel; D050051:Transient Receptor Potential Channels / Q000187:drug effects* / Q000378:metabolism
C000602225:4-(4-chlorophenyl)-3-methylbut-3-en-2-oxime; D000477:Alkylating Agents; D015220:Calcium Channels; D002619:Chemical Warfare Agents; D009419:Nerve Tissue Proteins; D010091:Oximes; D000074025:TRPA1 Cation Channel; C473350:TRPA1 protein, human; D050051:Transient Receptor Potential Channels; C031278:2-chloroethyl ethyl sulfide; D002118:Calcium; D009151:Mustard Gas