title: TRPA1 mediates mechanical currents in the plasma membrane of mouse sensory neurons.
abstract: Mechanosensitive channels serve as essential sensors for cells to interact with their environment. The identity of mechanosensitive channels that underlie somatosensory touch transduction is still a mystery. One promising mechanotransduction candidate is the Transient Receptor Potential Ankyrin 1 (TRPA1) ion channel. To determine the role of TRPA1 in the generation of mechanically-sensitive currents, we used dorsal root ganglion (DRG) neuron cultures from adult mice and applied rapid focal mechanical stimulation (indentation) to the soma membrane. Small neurons (diameter <27 microm) were studied because TRPA1 is functionally present in these neurons which largely give rise to C-fiber afferents in vivo. Small neurons were classified by isolectin B4 binding. Mechanically-activated inward currents were classified into two subtypes: Slowly Adapting and Transient. First, significantly more IB4 negative neurons (84%) responded to mechanical stimulation than IB4 positive neurons (54%). Second, 89% of Slowly Adapting currents were present in IB4 negative neurons whereas only 11% were found in IB4 positive neurons. Third, Slowly Adapting currents were completely absent in IB4 negative neurons from TRPA1-/- mice. Consistent with this, Slowly Adapting currents were abolished in wild type IB4 negative neurons stimulated in the presence of a TRPA1 antagonist, HC-030031. In addition, the amplitude of Transient mechanically-activated currents in IB4 positive neurons from TRPA1-/- mice was reduced by over 60% compared to TRPA1+/+ controls; however, a similar reduction did not occur in wild-type neurons treated with HC-030031. Transfection of TRPA1 in HEK293 cells did not significantly alter the proportion or magnitude of mechanically-activated currents in HEK293 cells, indicating that TRPA1 alone is not sufficient to confer mechanical sensitivity.These parallel genetic and pharmacological data demonstrate that TRPA1 mediates the Slowly Adapting mechanically-activated currents in small-diameter IB4 negative neurons from adult mice. The TRPA1 protein may also contribute to a complex that mediates Transient mechanically-activated currents in small IB4 positive C fiber type neurons.
authors.affiliation: Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America.
authors.forename: Daniel
authors.initials: D
authors.lastname: Vilceanu
authors.forename: Cheryl L
authors.initials: CL
authors.lastname: Stucky
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001696:Biomechanical Phenomena; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D005727:Ganglia, Spinal / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D005786:Gene Expression Regulation; D037102:Lectins / Q000172:deficiency / Q000378:metabolism; D008297:Male; D051379:Mice; D011984:Sensory Receptor Cells / Q000166:cytology* / Q000378:metabolism*; D000074025:TRPA1 Cation Channel; D013997:Time Factors; D050051:Transient Receptor Potential Channels / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*
chemical_list: D037102:Lectins; D000074025:TRPA1 Cation Channel; D050051:Transient Receptor Potential Channels; C475685:Trpa1 protein, mouse
references.citation: Pharmacol Ther. 2009 Sep;123(3):371-85
references.pmid: 19501617
references.citation: J Biol Chem. 2007 May 4;282(18):13180-9
references.pmid: 17353192
references.citation: Neuron. 2006 Apr 20;50(2):277-89
references.pmid: 16630838
references.citation: J Physiol. 2006 Dec 15;577(Pt 3):815-28
references.pmid: 17038434
references.citation: Nature. 2004 Jan 15;427(6971):260-5
references.pmid: 14712238
references.citation: Mol Pain. 2009 Apr 21;5:19
references.pmid: 19383149
references.citation: Nat Rev Mol Cell Biol. 2009 Jan;10(1):44-52
references.pmid: 19197331
references.citation: J Neurosci. 1999 Aug 1;19(15):6497-505
references.pmid: 10414978
references.citation: J Physiol. 2007 Aug 15;583(Pt 1):175-93
references.pmid: 17584831
references.citation: Structure. 2005 Apr;13(4):669-82
references.pmid: 15837205
references.citation: J Biol Chem. 1999 Mar 12;274(11):7325-33
references.pmid: 10066796
references.citation: Mol Pain. 2006 Aug 21;2:28
references.pmid: 16923187
references.citation: Nat Rev Neurosci. 2007 Jul;8(7):510-21
references.pmid: 17585304
references.citation: Physiol Rev. 2008 Oct;88(4):1449-90
references.pmid: 18923187
references.citation: J Neurosci. 2009 Apr 15;29(15):4808-19
references.pmid: 19369549
references.citation: Neurosci Lett. 1999 Oct 8;273(3):179-82
references.pmid: 10515188
references.citation: Nat Neurosci. 2007 Mar;10(3):277-9
references.pmid: 17259981
references.citation: Neurosci Lett. 2008 Jun 20;438(2):221-7
references.pmid: 18456404
references.citation: Cell. 2003 Mar 21;112(6):819-29
references.pmid: 12654248
references.citation: J Neurosci. 2002 Jun 15;22(12):RC228
references.pmid: 12045233
references.citation: J Pain. 2010 Jun;11(6):588-99
references.pmid: 20015699
references.citation: J Invest Dermatol. 2009 Sep;129(9):2312-5
references.pmid: 19282836
references.citation: Eur J Neurosci. 2009 Apr;29(8):1568-78
references.pmid: 19419422
references.citation: Proc Natl Acad Sci U S A. 2003 Dec 23;100(26):15959-64
references.pmid: 14671322
references.citation: J Neurophysiol. 2003 Jan;89(1):513-24
references.pmid: 12522198
references.citation: Curr Opin Neurobiol. 2009 Aug;19(4):362-9
references.pmid: 19683913
references.citation: EMBO J. 2009 May 20;28(10):1479-91
references.pmid: 19322198
references.citation: Neuropharmacology. 2009 Jun;56(8):1138-46
references.pmid: 19348834
references.citation: Proc Natl Acad Sci U S A. 2007 Aug 14;104(33):13525-30
references.pmid: 17686976
references.citation: Curr Opin Neurobiol. 2005 Aug;15(4):397-405
references.pmid: 16006117
references.citation: Nature. 2004 Dec 9;432(7018):723-30
references.pmid: 15483558