Immune Netw.  2012 Oct;12(5):217-221. 10.4110/in.2012.12.5.217.

Rheumatoid Fibroblast-like Synoviocytes Downregulate Foxp3 Expression by Regulatory T Cells Via GITRL/GITR Interaction

• Kim SH
• Youn J

• KMID: 2150752
• DOI: http://doi.org/10.4110/in.2012.12.5.217

Abstract

Fibroblast-like synoviocytes (FLS) colocalize with leukocyte infiltrates in rheumatoid synovia. Proinflammatory leukocytes are known to amplify inflammation by signaling to FLS, but crosstalk between FLS and regulatory T cells (Tregs) remains uncharacterized. To address this possibility, we cocultured FLS lines derived from arthritic mice with Tregs. FLS that expressed the ligand for glucocorticoid-induced TNF receptor family-related gene (GITR) decreased expression of Foxp3 and GITR in Tregs in a contact-dependent manner. This effect was abolished by blocking antibody to GITR. On the other hand, the Tregs caused the FLS to increase IL-6 production. These results demonstrate that inflamed FLS license Tregs to downregulate Foxp3 expression via the GITRL/GITR interaction while the Tregs induce the FLS to increase their production of IL-6. Our findings suggest that the interaction between FLS and Tregs dampens the anti-inflammatory activity of Tregs and amplifies the proinflammatory activity of FLS, thereby exacerbating inflammatory arthritis.

Keyword

Autoimmune arthritis; Regulatory T cells; Fibroblast-like synoviocytes; Foxp3

MeSH Terms

Animals
Arthritis
Hand
Inflammation
Interleukin-6
Leukocytes
Licensure
Mice
Receptors, Tumor Necrosis Factor
Synovial Fluid
T-Lymphocytes, Regulatory
Interleukin-6
Receptors, Tumor Necrosis Factor

Figure

• 

  Figure 1 FLS downregulate Foxp3 expression in a contact-dependent manner. Tregs were cultured with or without FLS. In some experiments, the Tregs and FLS were physically separated by transwells (designated as Tw). After 4 days of culture, cells were collected and assayed by FACS. FACS profiles gated on CD4+ cells are shown together with percentages of the indicated cell types. The data are representative of three (A, B) or two (C) independent experiments.

• 

  Figure 2 Involvement of GITRL-GITR in FLS-driven downregulation of Foxp3 in Tregs. (A), Two lines of FLS were assayed by RT-PCR to assess their levels of GITRL transcripts relative to β2m transcripts. (B), Tregs were cultured with or without FLS for 4 days in the presence of anti-GITR or control mAbs. The cells were harvested and assayed by FACS. FACS profiles gated on CD4+ cells are shown. Numbers indicate percentages of cells in the indicated quadrants. The data are representative of two (A) or three (B) independent experiments.

• 

  Figure 3 Coculture of FLS and Tregs increases IL-6 production. FLS and Tregs were cultured separately or together with anti-CD3/anti-CD28/IL-2 stimulation. After 4 days of culture, the culture supernatants were collected and assayed by ELISA. *p<0.05 and **p<0.01 by Student's t-test. The data are representative of five independent experiments.

Reference

1. Jang E, Kim HR, Cho SH, Paik DJ, Kim JM, Lee SK, Youn J. Prevention of spontaneous arthritis by inhibiting homeostatic expansion of autoreactive CD4+ T cells in the K/BxN mouse model. Arthritis Rheum. 2006. 54:492–498.

2. Chang SK, Gu Z, Brenner MB. Fibroblast-like synoviocytes in inflammatory arthritis pathology: the emerging role of cadherin-11. Immunol Rev. 2010. 233:256–266.

3. Cao D, Malmström V, Baecher-Allan C, Hafler D, Klareskog L, Trollmo C. Isolation and functional characterization of regulatory CD25brightCD4+ T cells from the target organ of patients with rheumatoid arthritis. Eur J Immunol. 2003. 33:215–223.

4. Nguyen LT, Jacobs J, Mathis D, Benoist C. Where FoxP3-dependent regulatory T cells impinge on the development of inflammatory arthritis. Arthritis Rheum. 2007. 56:509–520.

5. Jang E, Cho ML, Oh HJ, Youn J. Deficiency of foxp3 regulatory T cells exacerbates autoimmune arthritis by altering the synovial proportions of CD4 T cells and dendritic cells. Immune Netw. 2011. 11:299–306.

6. Sakaguchi S, Sakaguchi N, Asano M, Itoh M, Toda M. Immunologic self-tolerance maintained by activated T cells expressing IL-2 receptor alpha-chains (CD25). Breakdown of a single mechanism of self-tolerance causes various autoimmune diseases. J Immunol. 1995. 155:1151–1164.

7. Fontenot JD, Gavin MA, Rudensky AY. Foxp3 programs the development and function of CD4+CD25+ regulatory T cells. Nat Immunol. 2003. 4:330–336.

8. Chen W, Jin W, Hardegen N, Lei KJ, Li L, Marinos N, McGrady G, Wahl SM. Conversion of peripheral CD4⁺CD25^- naive T cells to CD4⁺CD25⁺ regulatory T cells by TGF-beta induction of transcription factor Foxp3. J Exp Med. 2003. 198:1875–1886.

9. Park HB, Paik DJ, Jang E, Hong S, Youn J. Acquisition of anergic and suppressive activities in transforming growth factor-beta-costimulated CD4⁺CD25^- T cells. Int Immunol. 2004. 16:1203–1213.

10. Zhou X, Bailey-Bucktrout SL, Jeker LT, Penaranda C, Martínez-Llordella M, Ashby M, Nakayama M, Rosenthal W, Bluestone JA. Instability of the transcription factor Foxp3 leads to the generation of pathogenic memory T cells in vivo. Nat Immunol. 2009. 10:1000–1007.

11. Xu L, Kitani A, Fuss I, Strober W. Cutting edge: regulatory T cells induce CD4+CD25-Foxp3- T cells or are self-induced to become Th17 cells in the absence of exogenous TGF-beta. J Immunol. 2007. 178:6725–6729.

12. Radhakrishnan S, Cabrera R, Schenk EL, Nava-Parada P, Bell MP, Van Keulen VP, Marler RJ, Felts SJ, Pease LR. Reprogrammed FoxP3+ T regulatory cells become IL-17+ antigen-specific autoimmune effectors in vitro and in vivo. J Immunol. 2008. 181:3137–3147.

13. Kobayashi K, Suda T, Nan-Ya K, Sakaguchi N, Sakaguchi S, Miki I. Cytokine production profile of splenocytes derived from zymosan A-treated SKG mice developing arthritis. Inflamm Res. 2006. 55:335–341.

14. Jang E, Cho WS, Cho ML, Park HJ, Oh HJ, Kang SM, Paik DJ, Youn J. Foxp3+ regulatory T cells control humoral autoimmunity by suppressing the development of long-lived plasma cells. J Immunol. 2011. 186:1546–1553.

15. Stephens GL, McHugh RS, Whitters MJ, Young DA, Luxenberg D, Carreno BM, Collins M, Shevach EM. Engagement of glucocorticoid-induced TNFR family-related receptor on effector T cells by its ligand mediates resistance to suppression by CD4+CD25+ T cells. J Immunol. 2004. 173:5008–5020.

16. Shimizu J, Yamazaki S, Takahashi T, Ishida Y, Sakaguchi S. Stimulation of CD25(+)CD4(+) regulatory T cells through GITR breaks immunological self-tolerance. Nat Immunol. 2002. 3:135–142.

17. Cohen AD, Schaer DA, Liu C, Li Y, Hirschhorn-Cymmerman D, Kim SC, Diab A, Rizzuto G, Duan F, Perales MA, Merghoub T, Houghton AN, Wolchok JD. Agonist anti-GITR monoclonal antibody induces melanoma tumor immunity in mice by altering regulatory T cell stability and intra-tumor accumulation. PLoS One. 2010. 5:e10436.

18. Bartok B, Firestein GS. Fibroblast-like synoviocytes: key effector cells in rheumatoid arthritis. Immunol Rev. 2010. 233:233–255.

19. Bettelli E, Carrier Y, Gao W, Korn T, Strom TB, MOukka , Weiner HL, Kuchroo VK. Reciprocal developmental pathways for the generation of pathogenic effector TH17 and regulatory T cells. Nature. 2006. 441:235–238.