Li Wen

Senior Research Scientist
Section of Endocrinology & Metabolism

Research Interests

Our main research focus is to better understand immunopathogenesis of autoimmune disorders in particular type 1 diabetes and our ultimate goal is to better design immunotherapy for the disease using various animal models of human type 1 diabetes.

1. The role of innate immunity in adaptive islet beta cell autoimmunity

The NOD mouse is an important animal model of type 1 diabetes (T1D). It is known that the incidence of spontaneous diabetes in NOD mice is influenced by environmental changes and may be reduced in response to environmental triggers, including microflora. This suggests that the innate immune system influences adaptive autoimmunity in NOD mice. However, how the TLR signaling pathway affects disease development is unknown. To characterize the role of innate immunity in adaptive islet autoimmunity, we have generated NOD mice deficient in different TLRs and/or MyD88, which is the “master” adaptor protein of TLR family. The natural history of diabetes suggests that there is different effect on the disease development by individual TLR deficiency. Our recent study using MyD88 deficient NOD mice suggests that the initiation of autoimmunity is genetically programmed and gut bacteria act as environmental modifier in regulation of the disease development. Our results support the hygiene hypothesis, that recognition of harmless commensal bacteria can stimulate development of immune regulatory responses, the theory proposed many years ago for allergy and asthma, and which also applies to T1D. We are now trying to understand the mechanism(s) of how gut flora, through innate immunity, balances host adaptive immune responses to non-self infection with self-tolerance. This will provide important insights into the interaction of gut flora with TLR signaling mediated by MyD88 in the pathogenesis of type 1 diabetes. Furthermore, this understanding may allow us to design and develop therapeutic targeting of innate immunity for disease prevention and/or treatment.

2. The role of B cell in islet beta cell autoimmunity and the mechanism of anti-CD20 therapy for type 1 diabetes

B cells play an important role in the immunopathogenesis of type 1 diabetes although the disease is known to be mediated by T cells. However, the precise roles of B cells in promoting type 1 diabetes have not been defined. To determine the efficacy of therapeutic B cell depletion by Rituximab (anti-CD20) and to investigate its potential mechanism of action, we generated a transgenic NOD mouse expressing human CD20 on B cells. A single cycle of anti-hCD20 treatment temporarily depleted B cells and significantly delayed and/or reduced the onset of diabetes. Furthermore, disease established to the point of clinical hyperglycemia could be reversed in over one third of diabetic mice. Why B cell depletion is therapeutic for a variety of autoimmune diseases is unclear, though effects on antibodies, cytokines and antigen presentation to T cells are thought to be important. In B-depleted NOD mice we identified a novel mechanism by which B cell depletion may lead to long-term remission: induction of dominant regulatory cells. Transfer studies demonstrated that these include both B and T cells. In this regard, B cell depletion was associated with expansion of T regulatory cells (CD4+CD25+Foxp3+ and CD4+CTLA4+) and B regulatory cells. We are currently investigating a) to optimize the best anti-CD20 treatment protocols for the greatest efficacy including combined therapy; b) to investigate the mechanism(s) of anti-CD20 induced immune regulation, especially the newly generated B regulatory cells; c) to study the effect of anti-CD20 therapy in islet transplantation.

3. Humanized mouse model of type 1 diabetes

We have generated different transgenic mice carrying human HLA genes that are either susceptible, such as DQ8 and/or DR4 or resistant, such as DQ6, to type 1 diabetes. Our early studies have demonstrated, in an in vivo spontaneous diabetes model, that MHC molecules are critical genes for the outcome of the disease. However, this model system has its limitations, such as they cannot be used to test the effects of clinical immune therapies as apart from MHC, T and B cells in these mice are still murine origin. An animal model that generates human immune responses leading to T1DM would create new opportunities for development, and would particularly accelerate progress in the area of therapeutics. We are in the process of generating a novel humanized mouse. The hope is that this novel humanized mouse will be a better recipient for human lymphocyte engraftment. This novel model will be tested for immunopathogenesis of type 1 diabetes and to test different therapies in order to improve safety and to understand mechanisms of action, also identify biomarkers of human immune responses of with cells from patients in a clinical trial.

4. The role of TLR in diabetes complications

Toll-like receptors (TLRs) are the vital molecules that identify microbial products and initiate immediate innate immune responses to the microbes. Recent studies suggest that TLRs are not only important in infections and sepsis, but also in inflammatory disorders (including vascular disease) and autoimmune diseases. It is particularly interesting that TLRs are also involved in metabolic disorders. Type 1 diabetes is a T cell mediated autoimmune disease but shares very similar disease complications with insulin resistant type 2 diabetes if the blood glucose is not well controlled. Little is known the effect of hyperglycemia on the immune cells, especially innate immune cells. We have recently generated NOD mice deficient in various TLRs. It has been suggested that TLRs play an important role in both primary and secondary (complication of diabetes) cardiovascular diseases, such as atherosclerosis. We are investigating the influence of high glucose on antigen presenting cells (macrophage, DC and B cells) that are critical for both innate and adaptive immunity and autoimmunity of the disease. The work is in progress. We will also investigate the effect of high glucose on endothelial cells, which are not only responsible for both macrovascular and microvascular complications but also function as “non-professional” antigen presenting cells. Lastly, we will study in vivo the role of TLRs in macrovascular (such as atherosclerosis) and microvascular (such as nephropathy) complications in TLR deficient diabetic mice. Since some types of TLR deficient NOD mice develop normal, if not accelerated, disease, this provides us a unique tool to study the role of innate immunity in diabetes complications.

Representative Publications

• L. Wen, S. Roberts, J. Viney, F.S. Wong, C. Mallick, C. Findly, Q. Peng, J. Craft, M. Owen & A. Hayday. Immunoglobulin synthesis and generalized autoimmunity in mice congenitally deficient in ab+ T cells. Nature 1994 369:654
• F.S. Wong, I. Visintin, L. Wen, R.A. Flavell and C.A. Janeway Jr. CD8 T cell clones can transfer rapid onset of diabetes in NOD mice in the absence of CD4 cells. J. Exp. Med. 183:67, 1996.
• L. Wen, W. Pao, F.S. Wong, Q.S. Peng, J. Craft, B. Zheng, G. Kelsoe, M.J. Owen and A.C. Hayday. Germinal center formation, immunoglobulin class switching, and autoantibody production driven by "non ab" T cells. J. Exp. Med. 183:2271, 1996
• D Zekzer, F.S. Wong, L. Wen, M Altieri, T Gurlo, H von Grafenstein, R.S. Sherwin. Inhibition of daibetes by an insulin-reactive CD4 T-cell clone in the nonobese daibetic mouse. Diabetes 46:1124-1132, 1997
• L Wen (corresponding author),, F.S. Wong, L Burkly, M Altieri, C Mamalaki, D Kiousis, R.A. Flavell, R.S. Sherwin. Induction of insulitis by glutamic acid decarboxylase peptide-specific and HLA-DQ8-restricted CD4+ T cells from human DQ transgenic mice. J. Clin. Invest. 102:947-957, 1998
• F.S. Wong, I Vinsintin, L Wen, J Granata, R.A. Flavell, C Janeway, Jr. The role of lymphocytes subsets in accelerated diabetes in NOD-RIP-B7.1 mice. J. Exp. Med. 187:1985-1993, 1998
• L. Wen (corresponding author), Y. Ma, D. Vergani and A. Hayday. ?? T cells in liver. In “T lymphocytes in the liver” Edited by I.N. Crispe. Wiley-Liss, Inc. p41-58, 1999
• F.S. Wong, J. Karttunen, C. Dumont, L. Wen, I. Visintin, I.M. Pilip, N. Shastri, E.G. Pamer and C.A. Janeway Jr. Identification of a MHC class I restricted autoantigen in type 1 diabetes by screening an organ-specific cDNA library. Nat. Med. 5:1026-1031, 1999
• L.Wen (corresponding author), F.S. Wong, J. Tang, N-Y Chen, M. Altieri, C. David, R. Flavell and R. Sherwin. In vivo evidence for the contribution of human histocompatibility leukocyte antigen (HLA)-DQ molecules tot he development of diabetes. J. Exp. Med. 191:97-104, 2000
• L. Wen (corresponding author), N-Y. Chan, J. Tang, R. Sherwin and F.S. Wong. The regulatory role of DR4 in a spontaneous diabetes DQ8 transgenic model. J. Clin. Invest. 107:871-880, 2001
• W. Gurr, R. Yavari, L. Wen, M. Shaw, C. Mora, L. Christa, and R. Sherwin. A Reg Family Protein Is Overexpressed in Islets From a Patient With New-Onset Type 1 Diabetes and Acts as T-Cell Autoantigen in NOD Mice. Diabetes 51:339-346, 2002
• L. Wen (corresponding author), F.S. Wong, R.Sherwin and C. Mora. Human DQ8 molecules can substitute for murine I-Ag7 in the selection of T cells restricted to I-Ag7. J. Immunol. 168:3635-3611, 2002
• F.S. Wong, A.K. Moustakas, L. Wen, G. K. Papadopoulos and C.A. Janeway. Analysis of Structure and Function Relationships of an Autoantigenic Peptide of Insulin Bound to H-2Kd that Stimulates CD8 T cells in Insulin-Dependent Diabetes Mellitus. PNAS, 99:5551-5556, 2002
• H. Moriyama, L. Wen, N. Abiru, E. Liu, L. Yu, D. Miao, R. Gianani, F. S. Wong and G. S. Eisenbarth. Induction and acceleration of Insulitis/Diabetes in mice with a viral mimic (Polyinosinic-cytodylic acid) and an insulin self-peptide. PNAS, 99:5539-5544, 2002
• F.S. Wong and L. Wen. The study of HLA and autoimmune diabetes. Curr. Mol. Med. 2003, 3:1-15
• L. Wen (corresponding author), ZJ Li, J Peng and FS Wong. The effect of innate immunity on autoimmune diabetes and the expression of Toll-like receptors on pancreatic islets. J. Immunol. 2004, 172:2173-3180
• S. Wong and L. Wen. What can the HLA Transgenic Mouse tell us about Autoimmune Diabetes? Diabetologia 2004. 47:1476-1487
• F.S. Wong, L Wen, M Tang, M Ramanathan, I Visintin, J Daugherty, LG. Hannum, C A. Janeway Jr. and M J. Shlomchik . Investigation of the Role of B lymphocytes in Type 1 Diabetes in the NOD mouse. Diabetes 2004. 53:2581-2587
• FS Wong, W Du, I Thomas and L Wen. The influence of major histocompatibility complex on development of autoimmune diabetes in RIP-B7.1 mice. Diabetes 2005, 54:2032-2040
• L Wen (corresponding author) and FS Wong. How can the innate immune system influence autoimmunity in type 1 diabetes and other autoimmune disorders? Critic. Rev. Immunol. 2005, 25:225-50
• F.S. Wong, W Du, I Thomas and L Wen. The influence of major histocompatibility complex on development of autoimmune diabetes in RIP-B7.1 mice. Diabetes 2005, 54:2032-2040
• FS Wong and L Wen. B cells in Autoimmune Diabetes. Review of Diabetes Studies 2:121-135, 2005
• W Du, F. S Wong, M O. Li, J Peng, H Qi RA. Flavell, R Sherwin and L Wen. TGF-b signaling is required for the function of Insulin Reactive T Regulatory Cells. J. Clin. Invest, 2006 116:1360-1370
• CY Hu, D Rodriguez-Pinto, W Du, A Ahuja, O Henegariu, FS Wong, MJ Shlomchik and L Wen. Autoimmune diabetes prevention and reversal by anti-CD20 therapy. J Clin. Invest. 2007, 117:3857-3867.
• L Wen, RE Ley, PY Volchkov, PB Stranges, L Avanesyan, AC Stonebraker, CY Hu, SF Wong, GL Szot, JA Bluestone, JI Gordon and AV Chervonsky. Innate immunity and intestinal microbiota in the development of type 1 diabetes. Nature, 2008, 455:1109-13

Education:

M.D., Capital College of Medicine, Beijing, China, 1983 Ph.D., Immunology, King's College, London, UK, 1992

Contact

Campus Address
Department of Internal Medicine
Section of Endocrinology
Yale University
School of Medicine
Box 208020
New Haven, CT
06520-8020

E-mail
li.wen@yale.edu

Telephone
203.785.7186