Nuclear factor-?B (NF-?B) is a transcription factor that plays many essential roles in immune responses in vivo, from contributing to the formation of lymph nodes and Peyer's patches to allowing generation and maturation of dendritic cells and controlling development and function of several T cell subsets. Several current immunosuppressive drugs to prevent solid organ transplant rejection, as well as many more in development, inhibit NF-?B as part of their mechanism of action. However, NF-?B is a ubiquitous transcription factor the inhibition of which can cause many severe side effects in different organ systems. In our previous funding period we showed that T cell-restricted inhibition of NF-?B, using transgenic mice that express an NF- ?B super-repressor selectively in T cells (I?B??N-Tg mice), results in permanent acceptance of fully allogeneic cardiac allografts and development of donor-specific tolerance via apoptosis of alloreactive T cells. In these mice, T cell-NF-?B activity is inhibited downstream of several receptors, including the TCR, Toll-like receptors (TLRs) and tumor necrosis factor receptor (TNFR) family members. To determine whether selective inhibition of TCR-NF-?B is sufficient for preventing allograft rejection, we have obtained CARMA1-KO mice that lack an adaptor molecule required for selectively linking the TCR and BCR to NF-?B. Our new results indicate that CARMA1-KO mice permanently accept fully allogeneic cardiac allografts, positioning the CARMA1-NF-?B axis as a very promising therapeutic target for clinical transplantation. Importantly, mice deficient in CARMA1 are an invaluable tool to understand the consequences of inhibition of this pathway on the development and differentiation of T cell subsets. We anticipate that drugs that would target NF-?B selectively in T cells rather than in all cell types may have fewer side effects than current immunosuppressive therapies while having the potential to induce transplantation tolerance. However, before developing such inhibitors, it is important to understand fully the function of TCR-CARMA1-NF-?B activity. Our current results indicate that targeting CARMA1 abolishes the thymic development of natural regulatory T cells (nTregs). Conversely, lack of CARMA1 promotes the differentiation of induced regulatory T cells (iTregs), underscoring CARMA1 as playing opposite functions in the generation of nTregs versus iTregs. Further supporting reciprocal requirements for iTreg and Th17 differentiation, our preliminary results indicate that absence of CARMA1 prevents Th17 differentiation. These results reveal novel functions of the TCR- CARMA1-NF-?B pathway that need to be substantiated mechanistically. The main goal of the current proposal is to define the precise role of CARMA1 and TCR-driven NF-?B in the development/differentiation of T cell subsets in vitro and in transplantation models in vivo.
Specific Aim 1. To determine the mechanisms by which CARMA1 regulates the thymic development of nTregs.
Specific Aim 2. To delineate the role of CARMA1-NF-?B in iTreg versus Th17 differentiation.

Public Health Relevance

We have recently shown that mice lacking CARMA1, an adaptor linking TCR to NF-?B, accept cardiac allografts long-term, suggesting that therapeutic targeting of this pathway may be sufficient for the induction of transplantation tolerance. Preliminary experiments reveal that the CARMA1 deficiency results in inhibition of Th17 and nTreg differentiation whereas it facilitates the generation of iTregs, positioning this molecule as having opposite effects for generation of nTregs versus iTregs. In this application we propose to investigate the mechanisms by which TCR-CARMA1-NF-?B regulates formation of nTregs, iTregs and Th17 cells and how these effects impact allograft fate.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI052352-09
Application #
8414829
Study Section
Transplantation, Tolerance, and Tumor Immunology (TTT)
Program Officer
Kehn, Patricia J
Project Start
2002-07-01
Project End
2015-01-31
Budget Start
2013-02-01
Budget End
2014-01-31
Support Year
9
Fiscal Year
2013
Total Cost
$326,641
Indirect Cost
$117,256
Name
University of Chicago
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
005421136
City
Chicago
State
IL
Country
United States
Zip Code
60637
Evaristo, C; Alegre, M-L (2013) IFN-ýý: The Dr. Jekyll and Mr. Hyde of immunology? Am J Transplant 13:3057-8
Molinero, Luciana L; Yang, Jianying; Gajewski, Thomas et al. (2009) CARMA1 controls an early checkpoint in the thymic development of FoxP3+ regulatory T cells. J Immunol 182:6736-43
Molinero, Luciana Lorena; Wang, Ying; Zhou, Ping et al. (2009) Fas mediates cardiac allograft acceptance in mice with impaired T-cell-intrinsic NF-kappaB signaling. Transpl Int 22:845-52
Molinero, L L; Zhou, P; Wang, Y et al. (2008) Epidermal Langerhans cells promote skin allograft rejection in mice with NF-kappa B-impaired T cells. Am J Transplant 8:21-31
Wang, Tongmin; Chen, Luqiu; Ahmed, Emily et al. (2008) Prevention of allograft tolerance by bacterial infection with Listeria monocytogenes. J Immunol 180:5991-9
Chen, Luqiu; Hussien, Yassir; Hwang, Kwang Woo et al. (2008) Overexpression of program death-1 in T cells has mild impact on allograft survival. Transpl Int 21:21-9
Chen, L; Wang, T; Zhou, P et al. (2006) TLR engagement prevents transplantation tolerance. Am J Transplant 6:2282-91
McNerney, M E; Lee, K-M; Zhou, P et al. (2006) Role of natural killer cell subsets in cardiac allograft rejection. Am J Transplant 6:505-13
Zhou, Ping; Balin, Samuel J; Mashayekhi, Mona et al. (2005) Transplantation tolerance in NF-kappaB-impaired mice is not due to regulation but is prevented by transgenic expression of Bcl-xL. J Immunol 174:3447-53