Atopic dermatitis (AD) is a chronic, relapsing skin disease that affects children and adults. This disease is a growing public health problem and a large economic burden worldwide. The central and most debilitating symptom in AD is chronic itch. While some patients can be treated successfully with existing therapies, there is a continuing need for the development of new therapies to treat patients who do not respond to current AD treatment strategies. We and others have shown that the production of the type 2 cytokines interleukin (IL)-4 and IL-13 by T helper type 2 (TH2) cells and newly identified group 2 innate lymphoid cells (ILC2s) contribute to AD pathogenesis. Preliminary studies have also shown that the receptors for IL-4 and IL- 13 are highly expressed on itch-sensing primary sensory neurons. However, the precise role of TH2 cells, ILC2s and type 2 cytokines in mediating AD-associated itch remains poorly defined. Further, type 2 cytokines are known to be dependent on Janus kinase (JAK) signaling in immune cells for their effector functions. However, whether JAK signaling in primary sensory neurons elicits itch remains unknown. The central hypothesis of this proposal is that atopic itch arises from interactions between type 2 immune cells and primary sensory neurons via JAK signaling. To test this, in Specific Aim 1 we will employ genetically modified TH2 cell- and/or ILC2-deficient mice to investigate the role of these immune cells and their associated cytokines in evoking neuronal excitation and itch behavior.
In Specific Aim 2, we will employ Cre-dependent conditional knockout mice in which Jak1 is selectively deleted from immune cells or primary sensory neurons to determine whether sensory neuron-specific JAK signaling mediates pruritogen-elicited neuronal activation and itch responses. We anticipate that gaining a better understanding of the immunologic pathways that interact with the primary pruriceptors to promote itch in the context of AD could lead to new anti-itch therapies.

Public Health Relevance

Atopic dermatitis (AD) is a common, chronic skin disorder with itch as its most debilitating symptom. This proposal will examine how the immune system directly interacts with the nervous system to promote the development of itch in AD. A better understanding of these pathways will be critical in developing new therapies for this disease.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR070116-02
Application #
9326912
Study Section
Arthritis, Connective Tissue and Skin Study Section (ACTS)
Program Officer
Cibotti, Ricardo
Project Start
2016-08-05
Project End
2021-06-30
Budget Start
2017-07-01
Budget End
2018-06-30
Support Year
2
Fiscal Year
2017
Total Cost
Indirect Cost
Name
Washington University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
068552207
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Luo, Jialie; Feng, Jing; Yu, Guang et al. (2017) Transient receptor potential vanilloid 4-expressing macrophages and keratinocytes contribute differentially to allergic and nonallergic chronic itch. J Allergy Clin Immunol :
Feng, Jing; Luo, Jialie; Mack, Madison R et al. (2017) The antimicrobial peptide human beta-defensin 2 promotes itch through Toll-like receptor 4 signaling in mice. J Allergy Clin Immunol 140:885-888.e6
Feng, Jing; Yang, Pu; Mack, Madison R et al. (2017) Sensory TRP channels contribute differentially to skin inflammation and persistent itch. Nat Commun 8:980
Oetjen, Landon K; Mack, Madison R; Feng, Jing et al. (2017) Sensory Neurons Co-opt Classical Immune Signaling Pathways to Mediate Chronic Itch. Cell 171:217-228.e13