Regulatory T cell (Treg) plays a critical role in maintaining immune system homeostasis and preventing autoimmunity and immunopathology. Compromised Treg function is linked to multiple autoimmune diseases. The development and maintenance of Treg cell lineage is dependent on transcription factor Foxp3, as loss of function mutations lead to severe lymphoproliferative disease in mice and humans. Thus, understanding the mechanisms that govern Foxp3 induction and stability may lead to novel therapies for autoimmune disease. Using a comparative genomic approach, Dr. Zheng and colleagues identified three evolutionarily conserved intronic cis-elements at the Foxp3 locus (conserved non-coding sequences (CNS) 1, 2 and 3). To elucidate the role of these CNS regions in Treg lineage development in vivo, they proceeded to knockout individual Foxp3 CNS regions in mice. Each of the three CNS knockout mice showed different defects in their Treg population, indicating the unique roles these CNS regions play in regulating Foxp3 expression. CNS2 is unique as it is located in the only CpG island at the Foxp3 locus. The methylation status of CNS2 is one of the most prominent epigenetic markers distinguishing Tregs from conventional T cells. Induction of Foxp3 is not affected by CNS2 deletion, but stabilization of Foxp3 expression is compromised. The mechanism underlying Treg lineage stability is not only a central question in the Treg biology field, but also has practical implications in Treg cell based therapy for autoimmune disease and organ transplant patients. The CNS2 KO mice provide a unique opportunity to explore the molecular and cellular mechanisms of Treg lineage stability in vitro and in vivo. Dr. Zheng's group will study the role of CNS2 in long-term maintenance of Treg stability in vivo, and determine if ex-Tregs are a major driver of autoimmunity (Aim 1). Additionally, they will address how Treg lineage stability is maintained under inflammation, a critical checkpoint for development of autoimmunity (Aim 2). They will dissect the molecular pathways that are involved in safeguarding Tregs under inflammatory conditions, which can potentially lead to drug targets for stabilizing Tregs for therapeutic purpose. Furthermore, Dr. Zheng's group will employ state-of-the-art mouse genetic tools to study the lineage stability of gut commensal induced iTregs (Aim 3). Since Treg lineage stability is directly related to the safety of Treg cell- based therapy for a variety of immune diseases, Dr. Zheng's study on CNS2 will provide insight on an important regulatory circuitry safeguarding Treg identity.

Public Health Relevance

Regulatory T cells (Tregs) are a subset of T lymphocytes that function as suppressor of the immune system and play a critical role in preventing autoimmune diseases. The goal of this project is to investigate the role of the CNS2 region at the Foxp3 genomic locus in protecting Treg cell lineage stability. The outcome of this project will be directy related to the validity and safety of Treg cell-based therapy for a variety of immune diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI107027-04
Application #
9197261
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Ramachandra, Lakshmi
Project Start
2014-01-01
Project End
2018-12-31
Budget Start
2017-01-01
Budget End
2017-12-31
Support Year
4
Fiscal Year
2017
Total Cost
Indirect Cost
Name
Salk Institute for Biological Studies
Department
Type
DUNS #
078731668
City
La Jolla
State
CA
Country
United States
Zip Code
92037
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Zheng, Ye (2017) A Rogue Foxp3 Mutant Undermines Treg Cell Function. Immunity 47:211-214
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He, Nanhai; Fan, Weiwei; Henriquez, Brian et al. (2017) Metabolic control of regulatory T cell (Treg) survival and function by Lkb1. Proc Natl Acad Sci U S A 114:12542-12547
Wang, Jianrong; He, Nanhai; Zhang, Na et al. (2017) NCoR1 restrains thymic negative selection by repressing Bim expression to spare thymocytes undergoing positive selection. Nat Commun 8:959
Chinen, Takatoshi; Kannan, Arun K; Levine, Andrew G et al. (2016) An essential role for the IL-2 receptor in Treg cell function. Nat Immunol 17:1322-1333
Liu, Wen-Hsien; Kang, Seung Goo; Huang, Zhe et al. (2016) A miR-155-Peli1-c-Rel pathway controls the generation and function of T follicular helper cells. J Exp Med 213:1901-19
Hernandez, Jeniffer B; Chang, Christina; LeBlanc, Mathias et al. (2015) The CREB/CRTC2 pathway modulates autoimmune disease by promoting Th17 differentiation. Nat Commun 6:7216
Bapat, Sagar P; Myoung Suh, Jae; Fang, Sungsoon et al. (2015) Depletion of fat-resident Treg cells prevents age-associated insulin resistance. Nature 528:137-41
Li, Xudong; Zheng, Ye (2015) Regulatory T cell identity: formation and maintenance. Trends Immunol 36:344-53

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