Journal club 2015.07.17.

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.
Publisher’s Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Journal club 2015.07.17. Read More »

Journal club 2015.07.10.

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.

Journal club 2015.07.10. Read More »

Journal club 2015.7.3

Unbiased classification of sensory neuron types by large-scale single-cell RNA sequencing

Abstract

The primary sensory system requires the integrated function of multiple cell types, although its full complexity remains unclear. We used comprehensive transcriptome analysis of 622 single mouse neurons to classify them in an unbiased manner, independent of any a priori knowledge of sensory subtypes. Our results reveal eleven types: three distinct low-threshold mechanoreceptive neurons, two proprioceptive, and six principal types of thermosensitive, itch sensitive, type C low-threshold mechanosensitive and nociceptive neurons with markedly different molecular and operational properties. Confirming previously anticipated major neuronal types, our results also classify and provide markers for new, functionally distinct subtypes. For example, our results suggest that itching during inflammatory skin diseases such as atopic dermatitis is linked to a distinct itch-generating type. We demonstrate single-cell RNA-seq as an effective strategy for dissecting sensory responsive cells into distinct neuronal types. The resulting catalog illustrates the diversity of sensory types and the cellular complexity underlying somatic sensation.

Journal club 2015.7.3 Read More »

Journal club 2015.6.19

Tryptase and protease-activated receptor-2 stimulate scratching behavior in a murine model of ovalbumin-induced atopic-like dermatitis.

Abstract

The aim of the current study was to investigate the involvement of tryptase and protease-activated receptor-2 (PAR2) in the pathogenesis of itch using a recently developed murine model of atopic dermatitis (AD) elicited by epicutaneous sensitization with ovalbumin (OVA). We also examined whether tacrolimus exerts an antipruritic effect. Epicutaneous sensitization of BALB/c mice with OVA led to a significant increase in the number of scratches. Notably, PAR2 mRNA and protein levels as well as cutaneous levels of tryptase were significantly enhanced in epicutaneously sensitized mice. Pretreatment with the protease inhibitor, leupeptin, PAR2 antibody, and tacrolimus significantly reduced the number of degranulated mast cells and tryptase content, and consequently alleviated scratching behavior. Cetirizine (10mg/kg) exerted a significant inhibitory effect on the scratching behavior of mice, but did not affect the number of degranulated mast cells and induction of tryptase. Our results collectively suggest that tryptase and PAR2 are involved in OVA allergy-induced scratching behavior.

Journal club 2015.6.19 Read More »

Journal Club 2015.06.12.

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.

Journal Club 2015.06.12. Read More »

Journal Club 2015.6.5

Oxaliplatin-Induced Peripheral Neuropathy via TRPA1 Stimulation in Mice Dorsal Root Ganglion Is Correlated with Aluminum Accumulation.

Abstract

Oxaliplatin is a platinum-based anticancer drug used to treat metastatic colorectal, breast, and lung cancers. While oxaliplatin kills cancer cells effectively, it exhibits several side effects of varying severity. Neuropathic pain is commonly experienced during treatment with oxaliplatin. Patients describe symptoms of paresthesias or dysesthesias that are triggered by cold (acute neuropathy), or as abnormal sensory or motor function (chronic neuropathy). In particular, we found that aluminum levels were relatively high in some cancer patients suffering from neuropathic pain based on clinical observations. Based on these findings, we hypothesized that aluminum accumulation in the dorsal root ganglion (DRG) in the course of oxaliplatin treatment exacerbates neuropathic pain. In mice injected with oxaliplatin (three cycles of 3 mg/kg i.p. daily for 5 days, followed by 5 days of rest), we detected cold allodynia using the acetone test, but not heat hyperalgesia using a hot plate. However, co-treatment with aluminum chloride (AlCl3∙6H2O; 7 mg/kg i.p. for 14 days: equivalent 0.78 mg/kg of elemental Al) and oxaliplatin (1 cycle of 3 mg/kg i.p. daily for 5 days, followed by 5 days of rest) synergistically induced cold allodynia as well as increased TRPAl mRNA and protein expression. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis showed a significant increase in aluminum concentrations in the DRG of mice treated with aluminum chloride and oxaliplatin compared to aluminum chloride alone. Similarly, in a mouse induced-tumor model, aluminum concentrations were increased in DRG tissue and tumor cells after oxaliplatin treatment. Taken together, these findings suggest that aluminum accumulation in the DRG may exacerbate neuropathic pain in oxaliplatin-treated mice.

Journal Club 2015.6.5 Read More »

Journal Club 2015.5.22

jid2015183a
Filename : jid2015183a.pdf (3 MB)
Caption :

Mechanisms Underlying the Scratching Behavior Induced by the Activation of Proteinase Activated Receptor-4 (PAR-4) in Mice.

Abstract

A role for proteinase-activated receptor-4 (PAR-4) was recently suggested in itch sensation. Here, we investigated the mechanisms underlying the pruriceptive actions of the selective PAR-4 agonist AYPGKF-NH2 (AYP) in mice. Dorsal intradermal (i.d.) administration of AYP elicited intense scratching behavior in mice, which was prevented by the selective PAR-4 antagonist (pepducin P4pal-10). PAR-4 was found to be co-expressed in 32% of tryptase-positive skin mast cells and AYP caused a 2-fold increase in mast cell degranulation. However, neither the treatment with cromolyn nor the deficiency of mast cells (WBB6F1-KitW/Wv mice) were able to affect AYP-induced itch. PAR-4 was also found on gastrin releasing peptide (GRP)-positive neurons (pruriceptive fibers), and AYP-induced itch was reduced by the selective GRP receptor antagonist RC-3095. In addition, AYP evoked calcium influx in ∼1.5% of cultured DRG neurons also sensitive to TRPV1 (capsaicin) and/or TRPA1 (AITC) agonists. Importantly, AYP-induced itch was reduced by treatment with either the selective TRPV1 (SB366791), TRPA1 (HC-030031) or NK1 (FK888) receptor antagonists. However, genetic loss of TRPV1, but not of TRPA1, diminished AYP-induced calcium influx in DRG neurons and the scratching behavior in mice. These findings provide evidence that PAR-4 activation by AYP causes pruriceptive itch in mice via a TRPV1/TRPA1-dependent mechanism.Journal of Investigative Dermatology accepted article preview online, 08 May 2015. doi:10.1038/jid.2015.183.jid2015183a

Journal Club 2015.5.22 Read More »

2015-05-15 Journal Club

TriCalm® hydrogel is significantly superior to 2% diphenhydramine and 1% hydrocortisone in reducing the peak intensity, duration, and overall magnitude of cowhage-induced itch

Clin Cosmet Investig Dermatol. 2015 Apr 24;8:223-9. doi: 10.2147/CCID.S78809. eCollection 2015.

Author information

 CCID-78809-tricalm—hydrogel-is-sig

Abstract

BACKGROUND:

Itch is one of the most frequent skin complaints and its treatment is challenging. From a neurophysiological perspective, two distinct peripheral and spinothalamic pathways have been described for itch transmission: a histaminergic pathway and a nonhistaminergic pathway mediated by protease-activated receptors (PAR)2 and 4. The nonhistaminergic itch pathway can be activated exogenously by spicules of cowhage, a tropical plant that releases a cysteine protease named mucunain that binds to and activates PAR2 and PAR4.

PURPOSE:

This study was conducted to assess the antipruritic effect of a novel over-the-counter (OTC) steroid-free topical hydrogel formulation, TriCalm(®), in reducing itch intensity and duration, when itch was induced with cowhage, and compared it with two other commonly used OTC anti-itch drugs.

STUDY PARTICIPANTS AND METHODS:

This double-blinded, vehicle-controlled, randomized, crossover study recorded itch intensity and duration in 48 healthy subjects before and after skin treatment with TriCalm hydrogel, 2% diphenhydramine, 1% hydrocortisone, and hydrogel vehicle, used as a vehicle control.

RESULTS:

TriCalm hydrogel significantly reduced the peak intensity and duration of cowhage-induced itch when compared to the control itch curve, and was significantly superior to the two other OTC antipruritic agents and its own vehicle in antipruritic effect. TriCalm hydrogel was eight times more effective than 1% hydrocortisone and almost six times more effective than 2% diphenhydramine in antipruritic action, as evaluated by the reduction of area under the curve.

CONCLUSION:

TriCalm hydrogel has a robust antipruritic effect against nonhistaminergic pruritus induced via the PAR2 pathway, and therefore it could represent a promising treatment option for itch.

KEYWORDS:

antipruritic treatment; head-to-head comparison; nonhistaminergic pruritus

PMID:
25941445
[PubMed]
PMCID:
PMC4416640

2015-05-15 Journal Club Read More »

Journal Club 2015.5.8

Cross-inhibition of NMBR and GRPR signaling maintains normal histaminergic itch transmission.

Abstract

We previously showed that gastrin-releasing peptide receptor (GRPR) in the spinal cord is important for mediating nonhistaminergic itch. Neuromedin B receptor (NMBR), the second member of the mammalian bombesin receptor family, is expressed in a largely nonoverlapping pattern with GRPR in the superficial spinal cord, and its role in itch transmission remains unclear. Here, we report that Nmbr knock-out (KO) mice exhibited normal scratching behavior in response to intradermal injection of pruritogens. However, mice lacking both Nmbr and Grpr (DKO mice) showed significant deficits in histaminergic itch. In contrast, the chloroquine (CQ)-evoked scratching behavior of DKO mice is not further reduced compared with Grpr KO mice. These results suggest that NMBR and GRPR could compensate for the loss of each other to maintain normal histamine-evoked itch, whereas GRPR is exclusively required for CQ-evoked scratching behavior. Interestingly, GRPR activity is enhanced in Nmbr KO mice despite the lack of upregulation of Grpr expression; so is NMBR in Grpr KO mice. We found that NMB acts exclusively through NMBR for itch transmission, whereas GRP can signal through both receptors, albeit to NMBR to a much lesser extent. Although NMBR and NMBR(+) neurons are dispensable for histaminergic itch, GRPR(+) neurons are likely to act downstream of NMBR(+) neurons to integrate NMB-NMBR-encoded histaminergic itch information in normal physiological conditions. Together, we define the respective function of NMBR and GRPR in itch transmission, and reveal an unexpected relationship not only between the two receptors but also between the two populations of interneurons in itch signaling.

Journal Club 2015.5.8 Read More »

journal club 2015-05-01

Mutual upregulation of endothelin-1 and IL-25 in atopic dermatitis.

Abstract

BACKGROUND:

Endothelin 1 (ET-1) has been reported to evoke histamine-independent pruritus in mammals. However, its association with pruritus or inflammation of atopic dermatitis (AD) has not been clarified. We sought to investigate the role of ET-1 in the skin inflammation of AD.

METHODS:

To examine the role of ET-1 in AD, we investigated the expression of ET-1 and IL-25 in the skin of an AD mouse model and AD patients, and examined the mutual regulatory relationship between ET-1 and IL-25, one of the important cytokines in AD, using the human HaCaT keratinocyte cell line.

RESULTS:

We immunohistochemically confirmed the upregulation of ET-1 and IL-25 expression in the epidermis of both the AD mouse model and AD patients. In vitro, IL-25 upregulated ET-1 mRNA and protein expression in a concentration- and time-dependent fashion in HaCaT cells. This IL-25-induced ET-1 expression was inhibited by ERK1/2 or JNK inhibitor. In a reciprocal manner, ET-1 also induced IL-25 upregulation. The enhancing effect of ET-1 on IL-25 was inhibited by an endothelin A receptor antagonist, ERK1/2 inhibitor or p38 inhibitor, but not by an endothelin B receptor antagonist or JNK inhibitor.

CONCLUSION:

These findings suggest that mutual upregulation of ET-1 and IL-25 takes place in the epidermis in AD, which may be a future target for anti-pruritic agents. This article is protected by copyright. All rights reserved.

This article is protected by copyright. All rights reserved.

KEYWORDS:

MAPK ; IL-25; Keratinocyte; atopic dermatitis; endothelin-1

 

http://onlinelibrary.wiley.com/doi/10.1111/all.12633/pdf

journal club 2015-05-01 Read More »

Scroll to Top