Asthma and other allergic diseases are widespread health problems for industrialized nations. In order to develop therapeutic agents that lessen the severity of these diseases, the biological processes that drive allergy need to be defined. Allergic reactions are triggered by excessive helper T cell responses to antigens; thus these cells are attractive targets for new therapeutics. The long-term objective of this proposal is to define specific intracellular signaling events within helper T cells that control the production of allergy- promoting cytokines such as IL-4. We have identified an important role for the cyclosporine receptor cyclophilin A (CypA) in regulating helper T cell responses. CypA alters the structure of peptide bonds adjacent to proline residues, and may thus regulate protein function by inducing conformational changes. Mice lacking CypA develop inflammation that contains eosinophils and mast cells, two cell types that have key roles in allergic responses. Helper T cells from these mice overproduce IL-4 and other allergy- associated cytokines and show increased activation of the key signaling molecule phospholipase C-gamma1 (PLCgl). A known regulator of PLCgl is Itk,a tyrosine kinase that controls IL-4 expression. CypA interacts with a proline residue in Itk ; this interaction promotes Itk self-association, which is postulated to downregulate Itk activity, and also inhibits contacts between Itk and other factors that promote PLCgl activation. Based on these findings, our central hypothesis is that CypA functions as represser of Itk activity, thus limiting IL-4 expression by helper T cells. To explore this hypothesis, we will pursue the following specific aims: 1) Identify amino acids that are required for interaction between Itk and CypA and for Itk self- association; biochemical assays will be used to assess how amino acid changes in Itk and CypA affect protein-protein interactions; 2) Determine the effects of mutations in CypA and Itk on function; CypA and Itk mutant proteins with altered function will be expressed in helper T cells to assess their impact onIL-4 expression and PLCgl activation; 3) Determine the role of CypA and Itk in allergic disease; how changes in CypA or Itk activity modulate asthma development in mouse model for this disease will be analyzed; 4) Determine whether CypA regulates the development of helper T cells that express allergy-promoting cytokines; a cell culture system will be used to define regulatory targets for CypA.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI067489-03
Application #
7407500
Study Section
Hypersensitivity, Autoimmune, and Immune-mediated Diseases Study Section (HAI)
Program Officer
Dong, Gang
Project Start
2006-03-15
Project End
2011-02-28
Budget Start
2008-03-01
Budget End
2009-02-28
Support Year
3
Fiscal Year
2008
Total Cost
$351,254
Indirect Cost
Name
University of Iowa
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
062761671
City
Iowa City
State
IA
Country
United States
Zip Code
52242
Chiba, Shigeki; Baghdadi, Muhammad; Akiba, Hisaya et al. (2012) Tumor-infiltrating DCs suppress nucleic acid-mediated innate immune responses through interactions between the receptor TIM-3 and the alarmin HMGB1. Nat Immunol 13:832-42
Hostager, Bruce S; Kashiwada, Masaki; Colgan, John D et al. (2011) HOIL-1L interacting protein (HOIP) is essential for CD40 signaling. PLoS One 6:e23061
Lu, Ping; Hankel, Isaiah L; Hostager, Bruce S et al. (2011) The developmental regulator protein Gon4l associates with protein YY1, co-repressor Sin3a, and histone deacetylase 1 and mediates transcriptional repression. J Biol Chem 286:18311-9
Kashiwada, Masaki; Cassel, Suzanne L; Colgan, John D et al. (2011) NFIL3/E4BP4 controls type 2 T helper cell cytokine expression. EMBO J 30:2071-82
Curtiss, Miranda L; Hostager, Bruce S; Stepniak, Elizabeth et al. (2011) Fyn binds to and phosphorylates T cell immunoglobulin and mucin domain-1 (Tim-1). Mol Immunol 48:1424-31
Hostager, Bruce S; Fox, Daniel K; Whitten, Douglas et al. (2010) HOIL-1L interacting protein (HOIP) as an NF-kappaB regulating component of the CD40 signaling complex. PLoS One 5:e11380
Lu, Ping; Hankel, Isaiah L; Knisz, Judit et al. (2010) The Justy mutation identifies Gon4-like as a gene that is essential for B lymphopoiesis. J Exp Med 207:1359-67
Colgan, John D; Hankel, Isaiah L (2010) Signaling pathways critical for allergic airway inflammation. Curr Opin Allergy Clin Immunol 10:42-7