A Sensory Neuron-expressed Interleukin-31 Receptor Mediates T helper Cell-dependent Itch: Involvement of TRPV1 and TRPA1

nihms540721

Ferda Cevikbas, PhD1,5,*, Xidao Wang, PhD2,*, Tasuku Akiyama, PhD3, Cordula Kempkes, PhD1, Terhi Savinko, PhD4, Attila Antal, MD5, Gabriela Kukova, MD5, Timo Buhl, MD1, Akihiko Ikoma, MD, PhD1, Joerg Buddenkotte, PhD6, Vassili Soumelis, MD7, Micha Feld, PhD5, Harri Alenius, PhD4, Stacey R. Dillon, PhD8, Earl Carstens, PhD3, Bernhard Homey, MD5,#,§, Allan Basbaum, PhD2,#,§, and Martin Steinhoff, MD, PhD1,5,#,§
1Depts. of Dermatology and Surgery, University of California San Francisco, San Francisco, CA, USA 2Depts. of Anatomy and W.M. Keck Foundation Center for Integrative Neuroscience, University California San Francisco, San Francisco, CA, USA 3Dept. of Neurobiology, University California Davis, CA, USA 4Unit of Toxicology, Finnish Institute of Occupational Health, Helsinki, Finland 5Dept. of Dermatology, University Hospital Duesseldorf, Duesseldorf, Germany 6Dept. of Dermatology, University Hospital Muenster, Muenster Germany 7Dep. of Immunology, Institut Curie, Paris, France 8ZymoGenetics, Inc. (a Bristol-Myers Squibb Company) Seattle, WA, USA

Abstract
Background—Although the cytokine, interleukin-31 (IL-31), has been implicated in
inflammatory and lymphoma-associated itch, the cellular basis for its pruritic action is yet unclear.
Objective—To determine whether immune cell-derived IL-31 directly stimulates sensory neurons, and to identify the molecular basis of IL-31-induced itch.
Methods—We used immunohistochemistry and qRTPCR to determine IL-31 expression levels in mice and humans. Immunohistochemistry, immunofluorescence, qRTPCR, in vivo pharmacology, western blotting, single cell calcium and electrophysiology were used to examine the distribution, functionality and cellular basis of the neuronal IL-31 receptor (IL-31RA) in mice and humans.
Results—Among all immune and resident skin cells examined, IL-31 was predominantly produced by TH2 and to a significantly lesser extend by mature dendritic cells. Cutaneous and intrathecal injections of IL-31 evoked intense itch, and its concentration increased significantly in murine atopic-like dermatitis skin. Both human and mouse DRG neurons express IL-31RA, largely in neurons that co-express TRPV1. IL-31-induced itch was significantly reduced in TRPV1- and TRPA1-deficient mice, not c-kit or PAR-2 mice. In cultured primary sensory neurons, IL-31 triggered Ca2+-release and ERK1/2 phosphorylation, Inhibition of which blocked IL-31 signaling in vitro and reduced IL-31-induced scratching in vivo.
Conclusion—IL-31RA is a functional receptor expressed by a small subpopulation of IL-31RA+/TRPV1+/TRPA1+ neurons, and is a critical neuro-immune link between TH2 cells and sensory nerves for the generation of T cell-mediated itch. Thus, targeting neuronal IL-31RA may be effective in the management of TH2-mediated itch, including atopic dermatitis and cutaneous T cell lymphoma.
Keywords
cytokine; atopic dermatitis; sensory nerve; skin; TRP channel

© 2013 American Academy of Allergy, Asthma and Immunology. Published by Mosby, Inc. All rights reserved.
#Addresses for correspondence: Martin Steinhoff, M.D., Ph.D., Departments of Dermatology and Surgery, University of California, San Francisco, 513 Parnassus Ave, Room S-1268, San Francisco, CA, 94143 USA, Phone: +1 415 476 6978, FAX: +1 415 476 0936, SteinhoffM@derm.ucsf.edu. Allan. I. Basbaum, Ph.D., Department of Anatomy, University of California, San Francisco, 1550 4th Street, San Francisco, CA, USA, Phone: +1 415 476 5270, FAX: +1 415 476 1974, Allan.Basbaum@ucsf.edu. Bernhard Homey, M.D.. Department of Dermatology. University Hospital Duesseldorf, Duesseldorf, Germany, Phone: +49 211 811 7600, FAX: +49 211 811 7316, bernhard.homey@uni-duesseldorf.de.
*contributed equally to this work; §Co-senior authors;
Author contribution:
F. C.: conducted most of the experiments, designed the study, wrote manuscript. X. W.: conducted in vivo and morphological experiments with F.C. T.A: performed single cell calcium measurement and electrophysiology recordings under supervision of E.C; T. S.: designed the study for the in vivo mouse models of AD under supervision of H.A; A.A, M.F.: performed human staining experiments of skin tissue and qPCR of cells under supervision of B.H.; C. K.: performed western blotting and wrote part of the manuscript; G. K.: performed human staining experiments of skin tissue and qPCR of cells; A. I.: assisted in cheek model assay; T. B.: stained human DRG for IL-31RA; H. A.: supervised the murine AD study; S. D.: supervised vivo mouse studies; E. C.: supervised electrophysiology study; B. H.: designed, supervised human IL-31 studies and mouse atopy models, and wrote manuscript; A.I.B.: designed, supervised the neuronal experiments, and wrote manuscript; M.S.: designed, supervised all experiments, analyzed data, and wrote manuscript.
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HTR7 Mediates Serotonergic Acute and Chronic Itch

HTR7 Mediates Serotonergic Acute and Chronic Itch

Takeshi Morita,1,2,7 Shannan P. McClain,1,7 Lyn M. Batia,1 Maurizio Pellegrino,1 Sarah R. Wilson,1,2 Michael A. Kienzler,3 Kyle Lyman,3 Anne Sofie Braun Olsen,3 Justin F. Wong,1 Cheryl L. Stucky,4 Rachel B. Brem,5,6,* and Diana M. Bautista1,2,* 1Department of Molecular & Cell Biology, 142 Life Sciences Addition, University of California, Berkeley, Berkeley, CA 94720-3200, USA 2Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
3Neurobiology Course, Marine Biological Laboratory, Woods Hole, MA 02543, USA
4Departments of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA 5Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, CA 94945, USA
6Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
7Co-first author
*Correspondence: rbrem@buckinstitute.org (R.B.B.), dbautista@berkeley.edu (D.M.B.) http://dx.doi.org/10.1016/j.neuron.2015.05.044

SUMMARY
Chronic itch is a prevalent and debilitating condition for which few effective therapies are available. We harnessed the natural variation across genetically distinct mouse strains to identify transcripts co-re- gulated with itch behavior. This survey led to the discovery of the serotonin receptor HTR7 as a key mediator of serotonergic itch. Activation of HTR7 promoted opening of the ion channel TRPA1, which in turn triggered itch behaviors. In addition, acute itch triggered by serotonin or a selective serotonin reuptake inhibitor required both HTR7 and TRPA1. Aberrant serotonin signaling has long been linked to a variety of human chronic itch conditions, in- cluding atopic dermatitis. In a mouse model of atopic dermatitis, mice lacking HTR7 or TRPA1 dis- played reduced scratching and skin lesion severity. These data highlight a role for HTR7 in acute and chronic itch and suggest that HTR7 antagonists may be useful for treating a variety of pathological itch conditions.

RESEARCH ARTICLE

Five hTRPA1 Agonists Found in Indigenous Korean Mint, Agastache rugosa

journal.pone.0127060

Hana Moon1☯, Min Jung Kim1☯, Hee Jin Son1, Hae-Jin Kweon2, Jung Tae Kim1, Yiseul Kim1, Jaewon Shim1, Byung-Chang Suh2, Mee-Ra Rhyu1*
1 Research Group of Food Functionality, Korea Food Research Institute, Bundang-gu, Sungnam-si, Gyeonggi-do, Republic of Korea, 2 Department of Brain Science, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea
☯ These authors contributed equally to this work. * mrrhyu@kfri.re.kr

Abstract
Transient receptor potential ankyrin1 (TRPA1) and transient receptor potential vanilloid 1 (TRPV1) are members of the TRP superfamily of structurally related, nonselective cation channels and mediators of several signaling pathways. Previously, we identified methyl syr- ingate as an hTRPA1 agonist with efficacy against gastric emptying. The aim of this study was to find hTRPA1 and/or hTRPV1 activators in Agastache rugosa (Fisch. et Meyer) O. Kuntze (A.rugosa), commonly known as Korean mint to improve hTRPA1-related phenome- na. An extract of the stem and leaves of A.rugosa (Labiatae) selectively activated hTRPA1 and hTRPV1. We next investigated the effects of commercially available compounds found in A.rugosa (acacetin, 4-allylanisole, p-anisaldehyde, apigenin 7-glucoside, L-carveol, β- caryophyllene, trans-p-methoxycinnamaldehyde, methyl eugenol, pachypodol, and ros- marinic acid) on cultured hTRPA1- and hTRPV1-expressing cells. Of the ten compounds, L-carveol, trans-p-methoxycinnamaldehyde, methyl eugenol, 4-allylanisole, and p-anisal- dehyde selectively activated hTRPA1, with EC50 values of 189.1±26.8, 29.8±14.9, 160.2 ±21.9, 1535±315.7, and 546.5±73.0 μM, respectively. The activities of these compounds were effectively inhibited by the hTRPA1 antagonists, ruthenium red and HC-030031. Al- though the five active compounds showed weaker calcium responses than allyl isothiocya- nate (EC50=7.2±1.4 μM), our results suggest that these compounds from the stem and leaves of A.rugosa are specific and selective agonists of hTRPA1.

Pain-sensing TRPA1 channel resolved
nature14383

The TRPA1 ion channel activates pain pathways in response to noxious compounds. The structure of TRPA1 has now been solved, providing insight into how it functions.Pain-sensing TRPA1 channel resolved