Arthritis & Rheumatism, Volume 60,
October 2009 Abstract Supplement

The 2009 ACR/ARHP Annual Scientific Meeting
Philadelphia October 16-21, 2009.


All-Trans Retinoic Acid Restores the Stability and Functionality of Ntregs in the Inflammatory Milieu

Zhou1,  Xiao H., Kong2,  Ning, Wang1,  Julie, Zou3,  Hejian, Fan4,  Huimin, Brand5,  David, Liu4,  Zhongmin

University of Southern California, Los Angeles, CA,
University of Southern California, Los Angeles, CA; Huashan Hospital, Fudan University, Shanghai, China,
Huashan Hospital, Fudan University, Shanghai, China,
East Hospital, Tongji University, Shanghai, China,
VA Medical Center, Memphis, Memphis, TN

Purpose:

Natural CD4+CD25+Foxp3+ cells (nTregs) play an important role in the maintenance of immune tolerance. Recent studies revealed that nTregs are plastic and unstable when stimulated with IL-6. They can be converted into either Th1, or Th17 or Th2 cells and lose phenotypic and functional characteristics in inflammatory milieu. all-trans Retinoic Acid (atRA) not only promotes Foxp3+ cell development, but restrains Th17 cell differentiation induced by IL-6+TGF-b. We hypothesize that atRA alters the plasticity of nTregs and restore their suppressive activities in an inflammatory milieu.

Method:

nTregs isolated from DBA/1J or Foxp3 knock-in mice were stimulated with IL-6 in the presence or absence of atRA, and intracellular IFN-g, IL-4, IL-17 expression was determined by FCM. nTregs were also pretreated by anti-CD3/CD28 with atRA or DMSO and these cells were re-stimulated with IL-6. IL-6 R and phosphorylated STAT3 expression in nTregs pretreated with atRA and control were analyzed by FCM and qRT-PCR. The suppressive activity in vitro of both nTregs pretreated with atRA or DMSO was compared using CFSE dilution of T responder cells that were stimulated with anti-CD3 in the presence of IL-6. 3×106 of both pretreated nTregs were i.v. injected into DBA/1J mice on the day 28 after immunization with CII and CFA. The clinical severity of collagen-induced arthritis (CIA) was evaluated by visual judge, measuring specific anti-CII IgG subsets and histological examination.

Results:

While 30% of nTregs were converted to Th17 cells when stimulated with IL-6, addition of atRA blocked Th17 conversion from nTregs. Similarly, atRA- but not DMSO-pretreated nTregs are also resistant to Th17 conversion when stimulated with IL-6. atRA-nTregs expressed lower levels of CD126 (IL-6Ra chain) and phosphorylated STAT3 compared to DMSO-nTregs when stimulated with IL-6. atRA- but not DMSO-nTregs maintained the suppressive activity in the presence of IL-6. Adoptive transfer of atRA- but not DMSO-pretreated nTregs to DBA/1 mice at day 28 after immunization with CII/CFA significantly reduced the severity of CIA. atRA-nTregs also suppressed CII-specific IgG production. Using CFSE-labeled donor cells, we were able to observe that majority of nTreg cells lost Foxp3 expression, converted to IL-17-prodcuing cells, and >20% converted into Th2 cells in draining lymph nodes at one week after adoptive transfer to the established CIA. Conversely, atRA-nTregs maintained Foxp3 expression and did not convert to Th1, Th2 and Th17 cells in a similar inflammatory milieu.

Conclusion:

atRA alters Treg plasticity and restores the functionality of nTregs in the inflammatory milieu. Decreased IL-6 receptor and its signal molecule expression on atRA-pretreated nTregs possibly contribute to their stability and functionality in established CIA. This study may provide a novel therapeutic approach for the treatment of Rheumatoid Arthritis.

To cite this abstract, please use the following information:
Zhou, Xiao H., Kong, Ning, Wang, Julie, Zou, Hejian, Fan, Huimin, Brand, David, et al; All-Trans Retinoic Acid Restores the Stability and Functionality of Ntregs in the Inflammatory Milieu [abstract]. Arthritis Rheum 2009;60 Suppl 10 :1969
DOI: 10.1002/art.27042

Abstract Supplement

Meeting Menu

2009 ACR/ARHP