Immunoregulation Section

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Richard Siegel, M.D., Ph.D.
Chief, Immunoregulation Section
Autoimmunity Branch (AB)
Phone: (301) 496-5767
Fax: (301) 480-3880

Research Overview

The goal of the Immunoregulation Group is to understand how alterations in regulatory signaling pathways in immune cells lead to abnormal immune responses, chronic inflammation, and autoimmune diseases. The TNF family of cytokines is the main focus of present work, as these cytokines are critical in the pathogenesis and treatment of a number of different autoimmune and inflammatory diseases. We are particularly interested in how membrane-proximal events in receptor signal transduction can be influenced by environmental or other signals to alter cellular responses, since understanding these principles may aid in designing more effective therapeutic strategies to modulate the effects of TNF-receptor family signaling in autoimmune and inflammatory diseases.   The general strategy of the lab is to better understand basic mechanisms of transmembrane signal transduction by selected TNF family receptors using the both cell and molecular biology approaches. We are also interested in studying the role of particular TNF family ligand-receptor systems in immune cells through mouse models. Recently, the lab has focused on three members of the TNF-receptor superfamily

  1. Fas and Fas Ligand: The Fas receptor has been shown to be important in immunoreceptor-mediated apoptosis of activated T and B lymphocytes. Both humans and mice with germ line mutations in the death receptor Fas accumulate abnormal lymphocytes and develop systemic autoimmunity. While most patients with non-familial autoimmune disease do not carry germ line Fas mutations, there is evidence that Fas-mediated apoptosis may be impaired in the milieu of chronic inflammation. We have been investigating what signals regulate Fas-mediated apoptosis in T cells, with the eventual aim of harnessing these discoveries to modulate Fas-induced apoptosis for therapeutic goals in human disease. We have recently identified the Rac family of small GTPases as critical regulators of Fas-induced apoptosis. We are also studying the regulation of FasL trafficking and function and are studying the role of the Wiskott-Aldrich Syndrome Protein (WASp) in this process
  2. TNF Receptor 1 (TNFR1). This receptor is critical for triggering inflammatory responses in myeloid cells of the immune system and other organ systems, and has been successfully targeted by biologic therapeutics in rheumatoid arthritis and other inflammatory diseases. We are working with the Genetics and Genomics Branch in NIAMS to understand the pathophysiology of inflammation in patients with the TNF Receptor Associated Periodic Syndrome (TRAPS) a genetic autoinflammatory disease associated with dominant mutations in TNFR1. We have recently discovered that TNFR1 mutant molecules associated with TRAPS are misfolded and accumulate in the endoplasmic reticulum. We are characterizing the mechanisms by which these mutant receptors lead to hyperactivity of the innate immune system.
  3. DR3: The function of this TNF-family receptor, highly related to TNFR1 but expressed mainly on lymphocytes has not been well characterized. We are investigating novel contributions of this receptor and its ligand, TL1A, to the pathophysiology of autoimmune diseases.

Receptor-induced cell death "Active Death"

Selected Publications

Klebanoff CA, Scott CD, Leonardi AJ, Yamamoto TN, Cruz AC, Ouyang C, Ramaswamy M, Roychoudhuri R, Ji Y, Eil RL, Sukumar M, Crompton JG, Palmer DC, Borman ZA, Clever D, Thomas SK, Patel S, Yu Z, Muranski P, Liu H, Wang E, Marincola FM, Gros A, Gattinoni L, Rosenberg SA, Siegel RM, Restifo NP. Memory T cell-driven differentiation of naive cells impairs adoptive immunotherapy. J Clin Invest. 2016 Jan;126(1):318-34. doi: 10.1172/JCI81217. Epub 2015 Dec 14. PubMed Icon

Richard AC, Ferdinand JR, Meylan F, Hayes ET, Gabay O, Siegel RM. The TNF-family cytokine TL1A: from lymphocyte costimulator to disease co-conspirator. J Leukoc Biol. 2015 Sep;98(3):333-45. doi: 10.1189/jlb.3RI0315-095R. Epub 2015 Jul 17. PubMed Icon

Richard AC, Tan C, Hawley ET, Gomez-Rodriguez J, Goswami R, Yang XP, Cruz AC, Penumetcha P, Hayes ET, Pelletier M, Gabay O, Walsh M, Ferdinand JR, Keane-Myers A, Choi Y, O'Shea JJ, Al-Shamkhani A, Kaplan MH4, Gery I, Siegel RM, Meylan F. The TNF-family ligand TL1A and its receptor DR3 promote T cell-mediated allergic immunopathology by enhancing differentiation and pathogenicity of IL-9-producing T cells. J Immunol. 2015 Apr 15;194(8):3567-82. doi: 10.4049/jimmunol.1401220. Epub 2015 Mar 18. PubMed Icon

Meylan F, Hawley ET, Barron L, Barlow JL, Penumetcha P, Pelletier M, Sciumè G, Richard AC, Hayes ET, Gomez-Rodriguez J, Chen X, Paul WE, Wynn TA, McKenzie AN, Siegel RM. The TNF-family cytokine TL1A promotes allergic immunopathology through group 2 innate lymphoid cells. Mucosal Immunol. 2014 Jul;7(4):958-68. doi: 10.1038/mi.2013.114. Epub 2013 Dec 25. PubMed Icon

Bulua AC, Mogul DB, Aksentijevich I, Singh H, He DY, Muenz LR, Ward MM, Yarboro CH, Kastner DL, Siegel RM, Hull KM. Efficacy of etanercept in the tumor necrosis factor receptor-associated periodic syndrome: a prospective, open-label, dose-escalation study. Arthritis Rheum. 2012 Mar;64(3):908-13. doi: 10.1002/art.33416. PubMed Icon

Meylan F, Richard AC, Siegel RM. TL1A and DR3, a TNF family ligand-receptor pair that promotes lymphocyte costimulation, mucosal hyperplasia, and autoimmune inflammation. Immunol Rev. 2011 Nov;244(1):188-96. PubMed Icon

Ramaswamy M, Deng M, Siegel RM. Harnessing programmed cell death as a therapeutic strategy in rheumatic diseases. Nat Rev Rheumatol. 2011 Mar;7(3):152-60. PubMed Icon

Bulua AC, Simon A, Maddipati R, Pelletier M, Park H, Kim KY, Sack MN, Kastner DL, Siegel RM. Mitochondrial reactive oxygen species promote production of proinflammatory cytokines and are elevated in TNFR1-associated periodic syndrome (TRAPS). J Exp Med. 2011 Mar 14;208(3):519-33. PubMed Icon

Steward-Tharp SM, Song YJ, Siegel RM, O'Shea JJ. New insights into T cell biology and T cell-directed therapy for autoimmunity, inflammation, and immunosuppression. Ann. N.Y. Acad. Sci. 2010 Jan;1183:123-48. PubMed Icon

Meylan F, Davidson TS, Kahle E, Kinder M, Acharya K, Jankovic D, Bundoc V, Hodges M, Shevach EM, Keane-Myers A, Wang EC, Siegel RM. The TNF-family receptor DR3 is essential for diverse T cell-mediated inflammatory diseases. Immunity. 2008 Jul;29(1):79-89. Epub 2008 Jun 19. PubMed Icon

See extended list of publications


Reviewed September 24, 2012