In the idiopathic inflammatory myopathies, disease pathogenesis remains largely undefined. However, we have recently published work demonstrating that immunization of different NOD and C57BL/6 congenic strains with murine histidyl-tRNA synthetase (Jo-1) generates muscle and lung inflammation resembling features of the anti-synthetase syndrome. The experimental approach outlined in this application extends these earlier studies through functional manipulation of dendritic cell (DC) phenotype to define characteristics of the Jo-1-specific immune response contributing to disease expression.
Specific Aim 1 employs different in vitro cytokine preparations and maturation stimuli to generate Jo-1-loaded DCs capable of skewing toward Th1, Th2, or Th17 immune responses targeting this antigen. Subsequent immunization of NOD and C57BL/6 congenic mice with Jo- 1-pulsed DCs cultivated under defined conditions will highlight the impact of antigen-specific T cell polarization on tissue inflammation in comparison to Jo-1/CFA immunization. Adoptive transfer of organ-infiltrating lymphocytes from DC-immunized to naive mice will firmly establish the relationship between Jo-1-specific autoimmune responses and the anti-synthetase syndrome. Parallel measurement of CFSE-labeled T cell proliferative responses and intracellular cytokine staining of antigen-challenged lymphocytes derived from spleen and organ-draining lymph nodes of DC-immunized mice will further link the observed tissue phenotype to Th17 and/or Th1-polarized, Jo-1-specific T cell responses. In contrast, use of alternative cytokine conditioning in Specific Aim 2 will generate Jo-1-loaded """"""""tolerogenic"""""""" DCs capable of blocking disease induction and, more importantly, re-establishing tolerance in existing disease. Complementing the in vivo assessment of Jo-1-pulsed tolerogenic DC immunization in disease preventioNot applicable.melioration, in vitro transwell mixing and antibody blocking experiments will define the relative contribution of anergy, bystander suppression, and contact-mediated inhibition to antigen-specific regulatory T cell function. The mechanistic insight provided by these studies will help to define immunologic targets and therapeutic approaches applicable to future human clinical trials.

Public Health Relevance

This project employs functional manipulation of antigen-pulsed dendritic cells to define the role of Jo-1-specific T cells in a murine model of inflammatory myopathy. This approach will clarify mechanisms of disease initiation/perpetuation and establish the feasibility of antigen- specific, dendritic cell-mediated tolerance induction. The latter objective is relevant to the treatment of multiple autoimmune diseases for which global immunosuppression is the only therapeutic option.

National Institute of Health (NIH)
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Exploratory/Developmental Grants (R21)
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Arthritis, Connective Tissue and Skin Study Section (ACTS)
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Mancini, Marie
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University of Pittsburgh
Internal Medicine/Medicine
Schools of Medicine
United States
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Fernandez, Irina; Harlow, Lisa; Zang, Yunjuan et al. (2013) Functional redundancy of MyD88-dependent signaling pathways in a murine model of histidyl-transfer RNA synthetase-induced myositis. J Immunol 191:1865-72
Soejima, Makoto; Kang, Eun Ha; Gu, Xinyan et al. (2010) Role of innate immunity in a model of histidyl-tRNA synthetase (Jo-1)-mediated myositis. Arthritis Rheum :