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.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Research Project (R01)
Project #
Application #
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
Fiscal Year
Total Cost
Indirect Cost
Duke University
Schools of Medicine
United States
Zip Code
Xie, Dan-Li; Zheng, Meng-Meng; Zheng, Yi et al. (2017) Vibrio vulnificus induces mTOR activation and inflammatory responses in macrophages. PLoS One 12:e0181454
Deng, Wenhai; Yang, Jialong; Lin, Xingguang et al. (2017) Essential Role of mTORC1 in Self-Renewal of Murine Alveolar Macrophages. J Immunol 198:492-504
Wang, Hong-Xia; Cheng, Joyce S; Chu, Shuai et al. (2016) mTORC2 in Thymic Epithelial Cells Controls Thymopoiesis and T Cell Development. J Immunol 197:141-50
Pan, Hongjie; Zhong, Xiao-Ping; Lee, Sunhee (2016) Sustained activation of mTORC1 in macrophages increases AMPK?-dependent autophagy to maintain cellular homeostasis. BMC Biochem 17:14
Wang, Hong-Xia; Qiu, Yu-Rong; Zhong, Xiao-Ping (2016) Intercellular Protein Transfer from Thymocytes to Thymic Epithelial Cells. PLoS One 11:e0152641
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 ??T17 Development and TCR?/? Recombination. PLoS Biol 14:e1002370
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:
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
Chen, Shelley S; Hu, Zhiming; Zhong, Xiao-Ping (2016) Diacylglycerol Kinases in T Cell Tolerance and Effector Function. Front Cell Dev Biol 4:130
Petrovski, Slavé; Parrott, Roberta E; Roberts, Joseph L et al. (2016) Dominant Splice Site Mutations in PIK3R1 Cause Hyper IgM Syndrome, Lymphadenopathy and Short Stature. J Clin Immunol 36:462-71

Showing the most recent 10 out of 34 publications