title: Extracellular pH and neuronal depolarization serve as dynamic switches to rapidly mobilize trkA to the membrane of adult sensory neurons.
abstract: Activation of the nerve growth factor (NGF) receptor trkA and tissue acidosis are critically linked to inflammation-associated nociceptor sensitization. This study explored how increased acidity is linked to sensory neuron sensitization to NGF. Adult Wistar rat primary sensory neurons grown at physiological pH 7.4, then either kept at pH 7.4 or challenged for 30 min in pH 6.5 medium, provided a model of acidosis. Nonpermeabilizing trkA immunofluorescence revealed a significant increase in trkA mobilization to the plasma membrane from intracellular stores in response to proton challenge. This was confirmed using a surface protein biotinylation assay and Brefeldin A disruption of the rough endoplasmic reticulum-Golgi-trans-Golgi network. Mobilization of trkA to the membrane at pH 6.5 was abolished in neurons treated with the acid-sensitive ion channel blocker, amiloride. While elevated levels of NGF-independent trkA phosphorylation occurred at pH 6.5 alone, the level of activation was significantly increased in response to NGF challenge. Exposure of sensory neurons to pH 6.5 medium also resulted in strong calcium (Ca(2+)) transients that were reversible upon reintroduction to physiological pH. The pH 6.5-induced mobilization of trkA to the membrane was Ca(2+) dependent, as BAPTA-AM Ca(2+) chelation abrogated the response. Interestingly, KCl-induced depolarization was sufficient to induce mobilization of trkA to the cell surface at pH 7.4, but did not augment the response to pH 6.5. In conclusion, increased mobilization of trkA to neuronal membranes in response to either acidosis or neuronal depolarization provides two novel mechanisms by which sensory neurons can rapidly sensitize to NGF and has important implications for inflammatory pain states.
authors: Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E5.
authors: Geoffrey E
authors: GE
authors: Bray
authors: Zhengxin
authors: Z
authors: Ying
authors: Landon D
authors: LD
authors: Baillie
authors: Ruiling
authors: R
authors: Zhai
authors: Sean J
authors: SJ
authors: Mulligan
authors: Valerie M K
authors: VM
authors: Verge
mesh_terms: D000138:Acidosis / Q000503:physiopathology; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D019921:Biotinylation; D020126:Brefeldin A / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D045604:Extracellular Fluid / Q000187:drug effects / Q000378:metabolism*; D005727:Ganglia, Spinal / Q000166:cytology; D006863:Hydrogen-Ion Concentration; D007456:Iodine Isotopes / Q000493:pharmacokinetics; D008297:Male; D020932:Nerve Growth Factor / Q000276:immunology / Q000493:pharmacokinetics; D011189:Potassium Chloride / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D020917:Receptor, trkA / Q000378:metabolism*; D011984:Sensory Receptor Cells / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000906:Antibodies; D002614:Chelating Agents; D007456:Iodine Isotopes; D011500:Protein Synthesis Inhibitors; D020126:Brefeldin A; D004533:Egtazic Acid; D011189:Potassium Chloride; D020932:Nerve Growth Factor; D020917:Receptor, trkA; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D002118:Calcium
references: Nature. 1997 Mar 13;386(6621):173-7
references: 9062189
references: J Neurosci. 1995 May;15(5 Pt 2):3982-9
references: 7751959
references: J Neurosci. 2000 Oct 1;20(19):7325-33
references: 11007890
references: J Neurosci. 2007 Aug 1;27(31):8190-201
references: 17670966
references: Eur J Neurosci. 2001 Jul;14(2):267-82
references: 11553278
references: Neuron. 2002 Sep 26;36(1):57-68
references: 12367506
references: Mol Cell Neurosci. 2009 Oct;42(2):102-115
references: 19520167
references: Science. 1988 Apr 8;240(4849):213-5
references: 2451291
references: Neurosci Lett. 1996 Apr 26;208(3):191-4
references: 8733302
references: J Exp Biol. 1987 Sep;132:133-50
references: 3323396
references: Eur J Neurosci. 1995 Jul 1;7(7):1484-94
references: 7551174
references: Nature. 1989 Jan 26;337(6205):362-4
references: 2911387
references: Circ Res. 2006 Sep 1;99(5):501-9
references: 16873722
references: Proc Natl Acad Sci U S A. 1998 Jul 21;95(15):8963-8
references: 9671787
references: J Biol Chem. 2003 Dec 5;278(49):48907-13
references: 14522957
references: J Neurosci. 2000 Oct 1;20(19):7417-23
references: 11007900
references: Pain. 1996 Aug;66(2-3):163-70
references: 8880837
references: J Mol Biol. 1999 Jul 2;290(1):149-59
references: 10388563
references: J Neurosci. 1997 Dec 15;17(24):9492-505
references: 9391005
references: Prog Brain Res. 1996;113:143-51
references: 9009732
references: J Comp Neurol. 1999 Oct 18;413(2):327-41
references: 10524342
references: Anal Biochem. 1976 May 7;72:248-54
references: 942051
references: EMBO J. 2005 Dec 21;24(24):4211-23
references: 16319926
references: J Biol Chem. 1987 Jul 5;262(19):9189-95
references: 2439506
references: Neuron. 1992 Nov;9(5):883-96
references: 1384575
references: Neuroscience. 2003;120(2):325-31
references: 12890505
references: Eur J Neurosci. 1999 May;11(5):1698-704
references: 10215923
references: J Neurosci. 1993 May;13(5):2136-48
references: 8478693
references: EMBO J. 1987 Apr;6(4):891-9
references: 3595562
references: Mol Pain. 2005 Nov 23;1:35
references: 16305749
references: Eur J Neurosci. 1994 Dec 1;6(12):1903-12
references: 7704300
references: Proc Natl Acad Sci U S A. 2001 Mar 13;98(6):3555-60
references: 11248116
references: Cold Spring Harb Protoc. 2009 Nov;2009(11):pdb.prot5316
references: 20150055
references: J Gen Physiol. 2006 Nov;128(5):509-22
references: 17074976
references: J Neurosci. 1989 Mar;9(3):914-22
references: 2538586
references: J Neurosci. 2009 Sep 16;29(37):11674-85
references: 19759314
references: J Biol Chem. 2009 May 1;284(18):12469-79
references: 19265194
references: Curr Pain Headache Rep. 2011 Jun;15(3):215-22
references: 21387163
references: Neuroscience. 2007 Mar 16;145(2):686-98
references: 17258862
references: J Neurosci. 2002 May 15;22(10):3939-52
references: 12019313
references: Dev Neurobiol. 2010 Apr;70(5):332-8
references: 20186712
references: J Neurosci Res. 1999 Jul 1;57(1):39-47
references: 10397634
references: Proc Natl Acad Sci U S A. 1998 Aug 4;95(16):9614-9
references: 9689129
references: Sci STKE. 2005 Jan 18;2005(267):pe1
references: 15657262
references: J Neurosci. 1995 Mar;15(3 Pt 1):2081-96
references: 7534343
references: Eur J Neurosci. 2002 Oct;16(8):1449-62
references: 12405958
references: J Cell Biol. 1992 Oct;119(2):259-72
references: 1400572
references: J Cell Biol. 2000 Sep 18;150(6):1423-34
references: 10995446
references: Cell. 1991 Nov 1;67(3):601-16
references: 1682055
references: J Clin Invest. 2002 Oct;110(8):1185-90
references: 12393854
references: J Neurosci. 1986 Aug;6(8):2312-21
references: 3018191
references: J Neurochem. 2001 May;77(3):864-75
references: 11331415
references: Nat Neurosci. 2001 Sep;4(9):869-70
references: 11528414
references: J Biol Chem. 2003 Oct 17;278(42):40744-8
references: 12900419
references: J Rheumatol. 1999 Sep;26(9):2018-24
references: 10493685
references: J Biol Chem. 1997 Sep 19;272(38):23547-51
references: 9295291
references: J Neurochem. 2001 Aug;78(3):515-23
references: 11483654
references: Nature. 2001 Jun 21;411(6840):957-62
references: 11418861
references: J Neurochem. 2008 Oct;107(2):398-417
references: 18691385
references: J Cell Biol. 1992 Mar;116(5):1071-80
references: 1740466
references: Neuron. 1998 Oct;21(4):681-93
references: 9808456
references: Pain. 2007 Dec 15;133(1-3):183-96
references: 17693023
references: Eur J Biochem. 1981 Apr;115(2):347-51
references: 7238509
references: Nature. 1977 Feb 24;265(5596):756-8
references: 16217
references: J Biol Chem. 1979 Jul 10;254(13):5972-82
references: 571871
references: J Pain. 2003 Aug;4(6):329-37
references: 14622690
references: Proc Natl Acad Sci U S A. 2007 Feb 20;104(8):2985-90
references: 17301229
references: EMBO J. 1994 Nov 15;13(22):5284-92
references: 7957094
references: Science. 1992 Jul 17;257(5068):395-7
references: 1321502
references: J Cell Sci. 1997 Jul;110 ( Pt 13):1453-63
references: 9224763
references: J Cell Biol. 1979 Jun;81(3):555-69
references: 457775
references: Proc Natl Acad Sci U S A. 2003 Jun 10;100(12):7319-24
references: 12777621
references: J Neurosci. 1992 Oct;12(10):4011-22
references: 1403097
references: Science. 1991 Apr 26;252(5005):554-8
references: 1850549
references: Neuron. 2003 Jan 9;37(1):121-33
references: 12526778
references: RNA. 2011 Jan;17(1):85-98
references: 21098654
references: J Neurosci. 2004 Dec 1;24(48):10974-9
references: 15574747
references: Proc Natl Acad Sci U S A. 2009 Jun 2;106(22):9093-8
references: 19458041
references: Neuroscience. 1994 Sep;62(2):327-31
references: 7530342
references: J Neurosci. 2009 Apr 29;29(17):5411-24
references: 19403809
references: J Neurosci. 2004 Jul 28;24(30):6650-8
references: 15282267
references: Neuron. 1994 Mar;12(3):691-705
references: 8155326
references: Nat Med. 1995 Aug;1(8):774-80
references: 7585179
references: Mol Interv. 2007 Feb;7(1):26-41
references: 17339604
references: Mol Cell Neurosci. 2009 Feb;40(2):128-42
references: 19022387
references: Anesthesiology. 2011 Jul;115(1):189-204
references: 21602663
references: EMBO J. 2008 Nov 19;27(22):3047-55
references: 18923424
references: Mol Pain. 2006 Mar 28;2:11
references: 16566843
references: Biochemistry. 1976 Dec 14;15(25):5543-52
references: 999827
references: J Neurocytol. 2003 Nov;32(9):1077-89
references: 15044840
references: FASEB J. 1999 Dec;13 Suppl 2:S251-6
references: 10619138
references: Neuroreport. 2001 Oct 8;12(14):3077-80
references: 11568640