While performing a DNA microarray gene expression analysis in collagen-induced arthritis (CIA), we discovered that a poorly-characterized gene, follistatin-like 1 (FSTL-1), was highly overexpressed in mouse paws during the early stages of arthritis. Especially-high expression was observed at the interface of synovial pannus and eroding bone, suggesting a role in joint destruction. Our Preliminary Studies provide strong evidence for a role for FSTL-1 in arthritis. Over-expression of FSTL-1 in mice resulted in severe paw swelling and arthritis, while neutralization of endogenous FSTL-1 ameliorated arthritis. We have also observed elevated expression of FSTL-1 in synovial tissues of patients with rheumatoid arthritis. Finally, we have now made the surprising observation that FSTL-1 induces maturation of IL-17-producing Th17 cells from naove CD4+ T cells. This finding represents a novel pathway for induction of Th17 cells, which have recently been shown to play a central role in autoimmunity, and whose maturation had previously been thought to require IL- 6 and TGF-. The current application will test the hypothesis that FSTL-1 plays a central role in arthritis and will explore the possibility that neutralization of FSTL-1 represents a novel therapeutic approach to the treatment of arthritis. The first Specific Aim is to determine the mechanism by which FSTL-1 induces inflammation. We will determine how FSTL-1 induces Th17 cells in vitro, whether FSTL-1 acts by a T cell receptor-dependent or independent pathway, whether FSTL-1 mediates its effect through a cell surface receptor, the FSTL-1 domain(s) responsible for the activity of FSTL-1 and whether FSTL-1 induces Th17 cells in vivo. The second Specific Aim is to determine the factors regulating FSTL-1 expression, including the tissue and cellular sources of FSTL-1 and the signals that induce FSTL-1 expression. The third Specific Aim is to determine the role of FSTL-1 in arthritis by overexpressing it, by neutralizing it in vivo with antibodies as well as by creating a conditional knockout. Understanding the properties of this novel protein will result in a better understanding of arthritis and possibly lead to new therapeutic targets.

Public Health Relevance

We have discovered a protein that plays a novel role in arthritis. Characterization of the properties of this protein is likely to lead to a better understanding of arthritis and possibly new therapies.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI073556-03
Application #
7897778
Study Section
Hypersensitivity, Autoimmune, and Immune-mediated Diseases Study Section (HAI)
Program Officer
Peyman, John A
Project Start
2008-07-01
Project End
2012-06-30
Budget Start
2010-07-01
Budget End
2011-06-30
Support Year
3
Fiscal Year
2010
Total Cost
$374,963
Indirect Cost
Name
University of Pittsburgh
Department
Pediatrics
Type
Schools of Medicine
DUNS #
004514360
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
Campfield, Brian T; Eddens, Taylor; Henkel, Matthew et al. (2017) Follistatin-like protein 1 modulates IL-17 signaling via IL-17RC regulation in stromal cells. Immunol Cell Biol 95:656-665
Blair, Harry C; Soboloff, Jonathan; Robinson, Lisa J et al. (2016) Suppression of arthritis-induced bone erosion by a CRAC channel antagonist. RMD Open 2:e000093
Chaly, Yury; Blair, Harry C; Smith, Sonja M et al. (2015) Follistatin-like protein 1 regulates chondrocyte proliferation and chondrogenic differentiation of mesenchymal stem cells. Ann Rheum Dis 74:1467-73
Campfield, Brian T; Nolder, Christi L; Marinov, Anthony et al. (2014) Follistatin-like protein 1 is a critical mediator of experimental Lyme arthritis and the humoral response to Borrelia burgdorferi infection. Microb Pathog 73:70-9
Chaly, Yury; Hostager, Bruce; Smith, Sonja et al. (2014) Follistatin-like protein 1 and its role in inflammation and inflammatory diseases. Immunol Res 59:266-72
Chaly, Yury; Fu, Yu; Marinov, Anthony et al. (2014) Follistatin-like protein 1 enhances NLRP3 inflammasome-mediated IL-1? secretion from monocytes and macrophages. Eur J Immunol 44:1467-79
Gorelik, Mark; Fall, Ndate; Altaye, Mekibib et al. (2013) Follistatin-like protein 1 and the ferritin/erythrocyte sedimentation rate ratio are potential biomarkers for dysregulated gene expression and macrophage activation syndrome in systemic juvenile idiopathic arthritis. J Rheumatol 40:1191-9
Gorelik, Mark; Wilson, David C; Cloonan, Yona K et al. (2012) Plasma follistatin-like protein 1 is elevated in Kawasaki disease and may predict coronary artery aneurysm formation. J Pediatr 161:116-9
Chaly, Yury; Marinov, Anthony D; Oxburgh, Leif et al. (2012) FSTL1 promotes arthritis in mice by enhancing inflammatory cytokine/chemokine expression. Arthritis Rheum 64:1082-8
Wilson, David C; Marinov, Anthony D; Blair, Harry C et al. (2010) Follistatin-like protein 1 is a mesenchyme-derived inflammatory protein and may represent a biomarker for systemic-onset juvenile rheumatoid arthritis. Arthritis Rheum 62:2510-6

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