Progress 12/01/09 to 11/30/13
Outputs
Target Audience: Scientists in the biomedical field, clinicians, and the general public who are interested in the potential health effects of natural products. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? This project provided both training and professional development for a Postdoctoral Research Associate (Junpeng Wang, Ph.D.) who was commited full time to this project, and a Ph.D. student (Munkyong Pae), who participated in many aspects of this project. Junpeng Wang, PhD, Postdoctoral Research Associate, and Dr. Munkyong Pae, a PhD student at the time of this work, conducted the work of EGCG supplementation on mouse autoimmune disease development, immunopathological changes, CD4 T cell differentiation, and T cell regulatory cytokines as well as their downstream signaling in mouse CD4 T cells. By participating in this project, they have further enriched their theoretical knowledge in the interaction of nutrition, immune function, and inflammatory disease. Also, in the course of this project, Drs. Wang and Pae have become more skillful in using laboratory techniques that are important to nutritional immunology research. As a result of this work and their respective accomplishments, Dr. Wang was promoted to the rank of Scientist III rank and Dr. Munkyong Pae was hired as a Postdoctoral Associate at Joslin Diabetes Center, Harvard Medical School, Boston, MA. How have the results been disseminated to communities of interest? Our results were presented at the annual Experimental Biology Conferences (2011, 2012, and 2013), and at the Immunology 2012 Conference, Boston, MA. Additionally, our work has resulted in several publications in peer-reviewed scientific journals. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
We have completed all the proposed studies and fulfilled all the specific research goals set to determine the efficacy of green tea component epigallocatechin-3-gallate (EGCG) in impeding the development of autoimmune disease as well as the underlying mechanism for this action. First, using the induced experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis, we determined the effect of dietary EGCG supplementation at different doses on disease symptoms and pathology, phenotype of immune cells in the central nervous system (CNS) and lymphoid tissue, and immune cell functions. Next, we determined how EGCG affects T cell activation, proliferation, and differentiation through impacting different and interactive signaling pathways to understand EGCG’s beneficial effect on T cell-mediated autoimmune disease. Additionally, as a further mechanistic exploration, we determined whether the effects of EGCG on CD4+ T cell differentiation are associated with its effects on the regulators and transcription factors as well as cytokines that control and regulate CD4+ T cell differentiation. Our results showed that EGCG dose-dependently attenuated the clinical symptoms, and pathology in central nervous system (CNS). This effect of EGCG is associated with inhibited functions of pathologic T cells as indicated by the reduced production of hallmark molecules responsible for inflammation and autoimmunity (IFN-γ, IL-17, IL-6, and TNF-α), decreased number of disease-causing T cells (Th1 and Th17), and increased number of anti-inflammation and pro-tolerance T cells (Treg) in lymph nodes, spleen, and CNS. We further demonstrated that the altered composition and function of T cells are due to the ability of EGCG to modulate the key elements that control T cell development into different functional populations. These results indicate that EGCG may attenuate the disease development of EAE by inhibiting immune cell infiltration and by modulating the balance among pro-and anti-autoimmune T cell subsets. Our findings suggest a potential benefit of EGCG in attenuating autoimmune diseases. The efficacy and working mechanisms of EGCG demonstrated in this study will help develop effective nutritional intervention as an alternative and complimentary approach to ameliorate autoimmune disease. Additonally, the model and markers chosen for this study can be used as powerful tools for identifying and assessing efficacy of potential dietary candidates in retarding autoimmune diseases.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Munkyong Pae, Dayong Wu. Immunomodulating effects of epigallocatechin-3-gallate from green tea: mechanisms and applications. Food Funct. 4:1287-1303, 2013.
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Progress 12/01/11 to 11/30/12
Outputs
OUTPUTS: During this period, we completed proposed studies to determine how green tea component epigallocatechin-3-gallate (EGCG) affects T cell activation, proliferation, and differentiation through impacting different and interactive signaling pathways to explain EGCGs beneficial effect on T cell-mediated autoimmune disease. Using an in vitro model, we determined how EGCG impacts differentiation of naive CD4 T cells into different effector lineages, which play different roles in the development of autoimmune disease. As a further mechanistic exploration, we also determined whether the effects of EGCG on CD4 T cell differentiation are associated with its effects on the regulators and transcription factors as well as cytokines that control and regulate CD4 T cell differentiation. Additionally, we utilized the plasma samples from the in vivo study, together with the results from the current in vitro study, to address the involvement of IL-6 and IL-6 receptors in EGCGs modulating effect on CD4 T cell differentiation. Completion of these studies has partly fulfilled our proposed Specific Aim 3. Our results were presented at the Immunology 2012 Conference, the 99th annual meeting of the American Association of Immunologists, held May 4-8, 2012 in Boston, MA. Dr. Junpeng Wang, the Postdoctoral Research Associate on this project, presented our findings at this meeting on our submitted abstract "Green tea epigallocatechin-3-gallate modulates differentiation of naive CD4 T cells into specific lineage effector cells." Additionally our findings have been published in peer-reviewed scientific journals (See Publications). PARTICIPANTS: Dayong Wu, MD, PhD, Associate Director of Nutritional Immunology Laboratory (NIL) at Jean Mayer-USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts University, is the Program Director of the project. Simin Nikbin Meydani, DVM, PhD, the Director of HNRCA and Director of Nutritional Immunology Laboratory (NIL), is the Co-investigator on the project. Junpeng Wang, PhD, Postdoctoral Research Associate, NIL and Munkyong Pae, an NIL PhD student, conducted the work of EGCG supplementation on mouse CD4 T cell differentiation and on T cell regulatory cytokines and their downstream signaling in mouse CD4 T cells. This project provided both training and professional development for both Dr. Wang and Ms. Pae, who has since completed her PhD and is a Postdoctoral Associate at Joslin Diabetes Center, Harvard Medical School, Boston, MA. TARGET AUDIENCES: Scientists in biomedical field, clinicians, and general public who are interested in the potential health effects of natural products. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Autoimmunity results from dysregulated pathological immune responses that cause the attack against self-tissues. It is believed that T cells, in particular CD4 T helper (Th) cells, play a key role in mediating several aspects of autoimmunity. Th subsets Th1, Th9, and Th17 cells are implicated in inducing autoimmunity whereas regulatory T cells (Treg) have a protective effect. We have previously shown that dietary EGCG attenuates experimental autoimmune encephalomyelitis (EAE) and alters CD4 T cell subpopulations. In the current study, which was mainly focused on the mechanistic investigation for EGCG-induced change in CD4 T cell differentiation, we learned that EGCG impeded Th1, Th9, and Th17 differentiation and prevented IL-6-induced suppression of Treg development. We further learned that EGCG inhibited specific transcription factors for Th1, Th9, and Th17 differentiation, which in turn may be mediated by EGCG-induced down-regulation of their corresponding transducers. EGCG-induced changes in Th17/Treg balance may be mediated by its inhibition of IL-6 signaling because EGCG inhibited soluble IL-6 receptor, membrane receptor gp130, and IL-6-induced phosphorylation of STAT3. This is also supported by the in vivo results showing that EAE mice fed EGCG had lower levels of IL-6 and soluble IL-6 receptor, but higher levels of soluble receptor gp130 in plasma. Together, these results suggest that EGCG modulates development of CD4 T cell lineages through impacting their respective and interactive regulatory networks, ultimately leading to an attenuated autoimmune response. This implies a potential application in controlling dysregulated T cell functions such as those observed in autoimmune and inflammatory disorders. The above results have provided us with mechanistic insight to help understand the protective effect of EGCG in T cell-mediated autoimmune disease. This information will be helpful in developing effective nutritional intervention as an alternative and complimentary approach to ameliorate autoimmune disease.
Publications
- Wang, J., Pae, M., Meydani, S.N., and Wu, D. 2012. Green tea epigallocatechin-3-gallate modulates differentiation of naive CD4 T cells into specific lineage effector cells. Journal of Molecular Medicine, Oct 12, 2012. DOI 10.1007/s00109-012-0964-2 [Epub ahead of print].
- Wang, J., Pae, M., Meydani, S., and Wu D. 2012. Green tea epigallocatechin-3-gallate modulates differentiation of naive CD4 T cells into specific lineage effector cells. Journal of Immunology, 188:123.6.
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Progress 12/01/10 to 11/30/11
Outputs
OUTPUTS: During this period, we completed part of the proposed studies to determine the underlying mechanisms by which the green tea component epigallocatechin-3-gallate (EGCG) exerts its effect on T cell function and T cell-mediated autoimmune disease. T cell cytokine IL-2 is an important regulatory molecule affecting multiple aspects of T cell biology. In addition to being a major growth factor that regulates T cell clonal expansion, their development into effector cells, and their survival, IL-2 is also a key factor in maintaining the tolerance necessary to prevent autoimmunity. We previously showed a suppressive effect of EGCG on T cell cycling and expansion as well as a paradoxical effect on IL-2 levels (up-regulating) and IL-2 receptor (IL-2R)alpha expression (down-regulating). We hypothesized that EGCG suppresses T cell response by affecting the cytokines responsible for maintaining T cell growth and homeostasis. To test this hypothesis, in the current study, we used an in vitro model to determine how EGCG modulates the expression and downstream signaling of T cell regulatory cytokines IL-2, IL-7, and IL-15, as well as their receptors. Completion of the current study has fulfilled part of our proposed Specific Aim 3. The results from this study have been published in a peer-reviewed scientific journal (See Publications). PARTICIPANTS: Dayong Wu, MD, PhD, Associate Director of Nutritional Immunology Laboratory (NIL) at Jean Mayer-USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts University, is the Program Director of the project. Simin Nikbin Meydani, DVM, PhD, the Director of HNRCA and Director of Nutritional Immunology Laboratory (NIL), is the Co-investigator on the project. Junpeng Wang, PhD, Postdoctoral Research Associate, NIL and Munkyong Pae, an NIL PhD student, conducted the work of EGCG supplementation on mouse CD4 T cell differentiation and on T cell regulatory cytokines and their downstream signaling in mouse CD4 T cells. This project provided both training and professional development for Dr. Wang and Ms. Pae, who has since completed her PhD and is a Postdoctoral Associate at Joslin Diabetes Center, Harvard Medical School, Boston, MA. TARGET AUDIENCES: Scientists in the biomedical field, clinicians, and the general public who are interested in the health effects of natural products. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
T cells are a key component in adaptive immune responses. While T cells are crucial for the hosts defense against invading pathogens and the surveillance for neoplasms within, they are also responsible for attacking self (autoimmunity) when their homeostasis is disturbed. We have previously shown that dietary EGCG attenuates experimental autoimmune encephalomyelitis (EAE), a T cell-mediated autoimmune disease. We also have found that EGCG suppresses T cell function and IL-2 signaling, which may contribute to its protective effect in autoimmune disease. In the current study, we have expanded our investigation by further determining how EGCG inhibits T cell response through its effect on the T cell cytokines involved in T cell growth and maintenance. From the results of the current study, we learned that EGCG inhibited anti-CD3/CD28-induced proliferation of naive CD4 T cells and increased accumulation of IL-2, but it inhibited expression of IL-2R including all its subunits (IL-2Ralpha, IL-2/IL-15Rbeta, common gamma chain) as well as IL-2R downstream signaling. Since IL-2R subunits IL-2/IL-15Rbeta- and gamma chains are shared with IL-15R and the gamma chain is shared with IL-7R, we suspected that EGCG might also influence the signaling of IL-15 and IL-7, the two key regulators in maintaining T cell homeostasis. Our results showed that EGCG suppressed IL-15 and IL-7 signaling; further, EGCG not only inhibited the subunits in IL-15R and IL-7R shared with IL-2R, but it also affected their proprietary alpha chains in a manner that aligns with an impaired signaling. Although IL-2, IL-15, and IL-7 have separate and distinctive roles in regulating T cells, all of them are critical for T cell survival, expansion, and differentiation. Thus, inhibited signaling of these cytokines by EGCG suggests an involvement of T cell growth cytokines in EGCG-induced T cell suppression through down-regulated expression of their receptors and downstream signaling. This implies a potential application in controlling dysregulated T cell functions such as those observed in autoimmune and inflammatory disorders. These results have provided us with mechanistic insight to help understand the suppressive effect of EGCG on T cell-mediated response, which in turn will help us to better understand the protective effect of EGCG in T cell-mediated autoimmune diseases and to develop effective nutritional interventions to treat these diseases.
Publications
- Wang, J., Pae, M., Meydani, S. N., and Wu, D. 2012. Epigallocatechin-3-gallate inhibits expression of receptors for T cell regulatory cytokines and their downstream signaling in mouse CD4 T cells. The Journal of Nutrition, 142: 566-571.
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Progress 12/01/09 to 11/30/10
Outputs
OUTPUTS: During this period, we completed proposed studies to determine whether green tea component epigallocatechin-3-gallate (EGCG) impedes development of autoimmune disease. First, we established an optimized study model in our lab. We successfully induced experimental autoimmune encephalomyelitis (EAE) in mice, an animal model for multiple sclerosis. Using this model we determined effect of dietary EGCG supplementation at different doses on disease onset, incidence, symptom score, pathology, phenotype of immune cells in central nervous system (CNS) and lymphoid tissue, and immune cell functions. In addition, we determined how dietary EGCG impacts inflammatory response in a dose-dependent manner in healthy mice. Completion of these studies has fulfilled the proposed Specific Aims 1 and 2. Our results were presented at the annual Experimental Biology 2011 Meeting, Washington, DC and published in several scientific journals. PARTICIPANTS: Dayong Wu, MD, PhD, Associate Director of Nutritional Immunology Laboratory (NIL) at Jean Mayer-USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts University, the program director of the project. Simin Nikbin Meydani, DVM, PhD, is the Director of HNRCA and also the Director of NIL, the co-investigator of the project. Junpeng Wang, PhD, a Post-doc Research Associate in NIL, conducted the work of determining effect of dietary EGCG on experimental autoimmune encephalomyelitis (EAE) in mice, an autoimmune disease model, and also effect of in vitro EGCG supplementation on T cell differentiation. Munkyong Pae, PhD student in NIL, conducted the work of determining effect of dietary EGCG on inflammatory response in normal mice, and effect of in vitro EGCG supplementation on T cell differentiation. Zhihong Ren, PhD, Research Associate in NIL, Yanmei Xu, visiting scholar in NIL and PhD student from China CDC, Sheng Xiao, PhD, instructor at Harvard Medical School, and Donald Smith, PhD, the manager of animal core service of HNRCA, have assisted Dr. Junpeng Wang in the work determining effect of dietary EGCG on EAE mice. Mohsen Meydani, DVM, PhD, Director of Vascular Biology Laboratory, and Fu Shang, PhD, a member of Laboratory for Nutrition and Vision, both at HNRCA, provided their advice in the study determining effect of dietary EGCG on inflammatory response in normal mice. TARGET AUDIENCES: Scientists in biomedical field, clinicians, and general public who are interested in the potential health effects of natural products. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Studies thus far have suggested that green tea epigallocatechin-3-gallate (EGCG) may have a beneficial effect in reducing pathogenesis of autoimmune diseases; however, the underlying mechanism(s) are not well understood. In this study, we determined effect of EGCG on experimental autoimmune encephalomyelitis (EAE), an animal model for human multiple sclerosis, and the underlying mechanisms. Female C57BL/6 mice were fed EGCG (0, 0.15, 0.3, and 0.6% in diet) for 30 d and then immunized with specific self antigen. EGCG dose dependently attenuated the clinical symptoms. EGCG also reduced the infiltration of pathologic immune cells into central nervous system (CNS) and the tissue damage they caused. In the mechanistic study, we learned that EGCG inhibited functions of pathologic T cells. EGCG reduced production of hallmark molecules responsible for inflammation and autoimmunity, such as IFN-gamma, IL-17, IL-6, and TNF-alpha, decreased the numbers of disease-causing T cells (Th1 and Th17), and increased the number of anti-inflammation and pro-tolerance T cells (Treg) in lymph nodes, spleen, and CNS. We further showed that the altered composition and function of T cells are due to the ability of EGCG to modulate the key elements that control T cell development into different functional populations. These results indicate that EGCG may attenuate the disease development of EAE by inhibiting immune cell infiltration and by modulating the balance among pro-and anti-autoimmune T cell subsets. Our findings suggest a potential benefit of EGCG in attenuating autoimmune diseases. The efficacy and working mechanisms of EGCG demonstrated in this animal study could help develop future clinical studies to test its application in human autoimmune diseases. Additonally, the model and markers chosen for this study can be used as powerful tools for identifying and assessing efficacy of potential candidates in retarding autoimmune diseases.
Publications
- Wang, J., Ren, Z., Xu, Y., Xiao, S., Meydani, S.N., Wu, D. 2012. Epigallocatechin-3-gallate Ameliorates Experimental Autoimmune Encephalomyelitis by Altering Balance among CD4+ T cell Subsets. Am. J. Pathol. 180: 221-234.
- Pae, M., Ren, Z., Meydani, M., Shang, F., Smith, D., Meydani, S.N., Wu, D. 2012. Dietary supplementation with green tea EGCG at high dose promotes inflammatory response. J. Nutr. Biochem. 2011, Jun 16. Epub ahead of print.
- Wu, D., Wang, J., Pae, M., Meydani, S.N. 2012. Green tea EGCG, T cells, and T cell-mediated autoimmune diseases. Mol Aspects Med. 33:107-118.
- Wu, D., Wang, J. 2011. The ability of green tea to alleviate autoimmune diseases, fact or fiction Expert Rev Clin Immunol. 7: 711-713.
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