T cell tolerance not only is critical in preventing autoimmune diseases but also contributes to tumor tolerance. T cell anergy and regulatory T cells (Treg) are two major forms of peripheral T cell tolerance. However, the specific mechanisms that control T cell anergy and Treg are still not well understood. Rapamycin has been utilized as an immunosuppressant for decades. Its target, the mammalian target of rapamycin (mTOR), is a serine threonine kinase that plays crucial roles in multiple cellular processes by regulating nutrient uptake, transcription, translation, autophagy, and cell survival. mTOR forms two signaling complexes (mTORC1 and mTORC2) with distinct signaling properties and sensitivities to rapamycin. Recent evidence has established mTOR as a crucial regulator for effector T cell differentiation, T cell anergy, inducible regulatory T cell differentiation, and memory T cell responses to viral pathogens. However, the pathways leading to mTOR activation in T cells and the importance of tight control of mTOR activity remain poorly understood. The objective of this proposal is to improve the understanding of mTOR signaling and the importance of the tumor suppressor tuberous complex 1 (TSC1) as a critical regulator for mTOR in the control of T cell tolerance. Using genetically manipulated mice and cell line models, we have recently revealed that the RasGRP1-Ras- Mek1/2-Erk1/2 pathway is critical for both mTORC1 and mTORC2 activation in T cells following T cell receptor (TCR) stimulation. We and others have also demonstrated that TSC1 inhibits mTORC1 but promotes mTORC2 signaling in T cells and is important for normal T cell homeostasis. Our central hypotheses for this proposal are 1) multiple signaling cascades downstream of the TCR control mTOR activation and 2) TSC1 is a critical regulator for inducible Treg and T cell anergy by tight contro of mTORC1 and mTORC2 signaling. With strong preliminary data, we plan to test our hypotheses by pursuing three specific aims.
In aim 1, we will investigate the mechanisms that control mTOR activation in T cells. We will test the hypothesis that Erk1/2 phosphorylate multiple substrates to promote mTORC1 and mTORC2 activation.
In aim 2, we will determine how TSC1 controls T cell anergy.
In aim 3, we will determine how TSC1 controls inducible Treg and helper T cell differentiation. The proposed studies will provide new insight into the understanding of mTOR signaling, the importance of TSC1 in T cells, and the mechanisms modulating T cell tolerance.

Public Health Relevance

Proper control of T cell activation and tolerance is important in preventing the pathogenesis of autoimmune diseases and mounting effective immune responses against cancer and pathogens. Studies in this proposal are expected to improve the understanding of mechanisms that regulate T cell activation and tolerance, which will have potential implications for the development of novel therapeutic strategies for these diseases.

Agency
National Institute of Health (NIH)
Type
Research Project (R01)
Project #
5R01AI101206-03
Application #
8652947
Study Section
Hypersensitivity, Autoimmune, and Immune-mediated Diseases Study Section (HAI)
Program Officer
Lapham, Cheryl K
Project Start
Project End
Budget Start
Budget End
Support Year
3
Fiscal Year
2014
Total Cost
Indirect Cost
Name
Duke University
Department
Pediatrics
Type
Schools of Medicine
DUNS #
City
Durham
State
NC
Country
United States
Zip Code
27705
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Yang, Jialong; Lin, Xingguang; Pan, Yun et al. (2016) Critical roles of mTOR Complex 1 and 2 for T follicular helper cell differentiation and germinal center responses. Elife 5:
Wang, Hong-Xia; Shin, Jinwook; Wang, Shang et al. (2016) mTORC1 in Thymic Epithelial Cells Is Critical for Thymopoiesis, T-Cell Generation, and Temporal Control of γδT17 Development and TCRγ/δ Recombination. PLoS Biol 14:e1002370
Wang, Hong-Xia; Qiu, Yu-Rong; Zhong, Xiao-Ping (2016) Intercellular Protein Transfer from Thymocytes to Thymic Epithelial Cells. PLoS One 11:e0152641
Yang, Jialong; Zhang, Ping; Krishna, Sruti et al. (2016) Unexpected positive control of NFκB and miR-155 by DGKα and ζ ensures effector and memory CD8+ T cell differentiation. Oncotarget 7:33744-64
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Lin, Xingguang; Yang, Jialong; Wang, Jinli et al. (2016) mTOR is critical for intestinal T-cell homeostasis and resistance to Citrobacter rodentium. Sci Rep 6:34939
Ci, Xinxin; Kuraoka, Masayuki; Wang, Hongxia et al. (2015) TSC1 Promotes B Cell Maturation but Is Dispensable for Germinal Center Formation. PLoS One 10:e0127527
Yang, Wei; Gorentla, Balachandra; Zhong, Xiao-Ping et al. (2015) mTOR and its tight regulation for iNKT cell development and effector function. Mol Immunol 68:536-45
Wu, Jinhong; Yang, Jialong; Yang, Kai et al. (2014) iNKT cells require TSC1 for terminal maturation and effector lineage fate decisions. J Clin Invest 124:1685-98

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