title: Streptozotocin Stimulates the Ion Channel TRPA1 Directly: INVOLVEMENT OF PEROXYNITRITE.
abstract: Streptozotocin (STZ)-induced diabetes is the most commonly used animal model of diabetes. Here, we have demonstrated that intraplantar injections of low dose STZ evoked acute polymodal hypersensitivities in mice. These hypersensitivities were inhibited by a TRPA1 antagonist and were absent in TRPA1-null mice. In wild type mice, systemic STZ treatment (180 mg/kg) evoked a loss of cold and mechanical sensitivity within an hour of injection, which lasted for at least 10 days. In contrast, Trpa1(-/-) mice developed mechanical, cold, and heat hypersensitivity 24 h after STZ. The TRPA1-dependent sensory loss produced by STZ occurs before the onset of diabetes and may thus not be readily distinguished from the similar sensory abnormalities produced by the ensuing diabetic neuropathy. In vitro, STZ activated TRPA1 in isolated sensory neurons, TRPA1 cell lines, and membrane patches. Mass spectrometry studies revealed that STZ oxidizes TRPA1 cysteines to disulfides and sulfenic acids. Furthermore, incubation of tyrosine with STZ resulted in formation of dityrosine, suggesting formation of peroxynitrite. Functional analysis of TRPA1 mutants showed that cysteine residues that were oxidized by STZ were important for TRPA1 responsiveness to STZ. Our results have identified oxidation of TRPA1 cysteine residues, most likely by peroxynitrite, as a novel mechanism of action of STZ. Direct stimulation of TRPA1 complicates the interpretation of results from STZ models of diabetic sensory neuropathy and strongly argues that more refined models of diabetic neuropathy should replace the use of STZ.
authors.affiliation: From the Wolfson Centre for Age-related Diseases, Hodgkin Building, Guy's Campus, King's College London, London SE1 1UL, United Kingdom, david.andersson@kcl.ac.uk.
authors.forename: David A
authors.initials: DA
authors.lastname: Andersson
authors.affiliation: the Bioinorganic Chemistry Division, Department of Chemistry and Pharmacy, University of Erlangen-Nuremberg, Egerlandstrasse 1, 91058 Erlangen, Germany.
authors.forename: Milos R
authors.initials: MR
authors.lastname: Filipović
authors.affiliation: From the Wolfson Centre for Age-related Diseases, Hodgkin Building, Guy's Campus, King's College London, London SE1 1UL, United Kingdom.
authors.forename: Clive
authors.initials: C
authors.lastname: Gentry
authors.affiliation: the Department of Anesthesiology and Intensive Care, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany, and.
authors.forename: Mirjam
authors.initials: M
authors.lastname: Eberhardt
authors.affiliation: From the Wolfson Centre for Age-related Diseases, Hodgkin Building, Guy's Campus, King's College London, London SE1 1UL, United Kingdom.
authors.forename: Nisha
authors.initials: N
authors.lastname: Vastani
authors.affiliation: the Department of Anesthesiology and Intensive Care, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany, and.
authors.forename: Andreas
authors.initials: A
authors.lastname: Leffler
authors.affiliation: the Institute of Physiology and Pathophysiology, University of Erlangen-Nuremberg, Universitaetsstrasse 17, D-91054 Erlangen, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Reeh
authors.affiliation: From the Wolfson Centre for Age-related Diseases, Hodgkin Building, Guy's Campus, King's College London, London SE1 1UL, United Kingdom.
authors.forename: Stuart
authors.initials: S
authors.lastname: Bevan
mesh_terms: D000700:Analgesics / Q000494:pharmacology; D000818:Animals; D013058:Mass Spectrometry; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D010084:Oxidation-Reduction; D030421:Peroxynitrous Acid / Q000378:metabolism*; D013311:Streptozocin / Q000494:pharmacology*; D000074025:TRPA1 Cation Channel; D050051:Transient Receptor Potential Channels / Q000737:chemistry / Q000187:drug effects* / Q000235:genetics
chemical_list: D000700:Analgesics; D000074025:TRPA1 Cation Channel; D050051:Transient Receptor Potential Channels; C475685:Trpa1 protein, mouse; D030421:Peroxynitrous Acid; D013311:Streptozocin
keywords: diabetes; dorsal root ganglia; pain; reactive nitrogen species; reactive oxygen species; streptozotocin; transient receptor potential channels (TRP channels)