Arthritis & Rheumatism, Volume 60,
October 2009 Abstract Supplement

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


All-Trans Retinoic Acid Promotes the Differentiation of Itreg Cells Via Smad and Non-Smad Signaling Pathways

Zhou1,  Xiao H., Lu1,  Ling, Wang1,  Julie, Zou2,  Hejian, Horwitz1,  David A., Brand3,  David, Fan4,  Huimin

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

Purpose:

Recent studies have revealed that All-trans Retinoic Acid (ATRA), a vitamin A derivative, promotes the development of CD4+Foxp3+ regulatory T cells induced by TGF-b (iTreg), however, the mechanisms by which ATRA regulates the differentiation of iTreg remain poorly understood.

Method:

Naïve CD4+CD25- cells isolated from wild type or Smad3 KO or Smad2 conditional KO in T cells were stimulated with anti-CD3/CD28 beads ± TGF-b± ATRA for 5 days. Phenotype and functional activity was determined by FACS. TGF-bRI and TGF-bRII expression was determined by qRT-PCR. Western blot detected the Smad2/3, ERK1/2, P-38 and JNK activation. CHIP assay detected acetylation of Foxp3 protein. A methyl-sensitive PCR was used to analyze the methylation status of the CpG island of the Foxp3 promoter.

Results:

We confirmed ATRA markedly increased the conversion of CD4+Foxp3+ iTreg cells in wild type and Foxp3 GFP transgenic mice. Additionally, we observed ATRA increased the Foxp3 binding ability with chromatin although it did not decrease hypermethylation of Foxp3 promoter and increase acetylation of Foxp3 protein. ATRA increased the Foxp3 binding on IL-2 promoter. Both ATRA and TGF-b treated cells developed mote potent anergy status and suppressive activity in vitro and in vivo. ATRA markedly increased the expression of CD103, alpha4-beta7, alphaV-beta8, CCR-9 on TGF-b treated CD4+ cells although it did not affect TGF-b receptor I and receptor II expression. CD4+ cells treated with both ATRA/TGF-b produced markedly lower amounts of IL-2 but higher amount of IL-10. ATRA also suppressed the apoptosis and sustained the Foxp3 expression. Although ATRA significantly increased the phosphorylated Smad2/Smad3 expression, ATRA still increased the Foxp3 expression and suppressive activity of TGF-b-treated CD4+ cells in Smad3 KO and Samd2 conditional KO mice. In addition, ATRA markedly increased ERK1/2 activation on TGF-b treated CD4+ cells and blockade of ERK1/2 signal significantly decreased the increased Foxp3 expression.

Conclusion:

ATRA mainly activate Erk1/2 to promote the differentiation of iTreg cells. ATAR also enhances its binging ability on its target gene and alterations of the distribution and structure of Foxp3 might account for increased suppressive activity.

To cite this abstract, please use the following information:
Zhou, Xiao H., Lu, Ling, Wang, Julie, Zou, Hejian, Horwitz, David A., Brand, David, et al; All-Trans Retinoic Acid Promotes the Differentiation of Itreg Cells Via Smad and Non-Smad Signaling Pathways [abstract]. Arthritis Rheum 2009;60 Suppl 10 :1896
DOI: 10.1002/art.26969

Abstract Supplement

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