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Downregulation of NFAT3 Due to Lack of T-Box Transcription Factor TBX5 Is Crucial for Cytokine Expression in T Cells.

Authors
  • Kaminuma, Osamu1, 2
  • Kitamura, Noriko3
  • Nishito, Yasumasa4
  • Nemoto, Soichi5
  • Tatsumi, Hideki5
  • Mori, Akio6
  • Hiroi, Takachika3
  • 1 Allergy and Immunology Project, The Tokyo Metropolitan Institute of Medical Science, Tokyo 113-8613, Japan; [email protected] , (Japan)
  • 2 Center for Life Science Research, University of Yamanashi, Yamanashi 409-3898, Japan. , (Japan)
  • 3 Allergy and Immunology Project, The Tokyo Metropolitan Institute of Medical Science, Tokyo 113-8613, Japan. , (Japan)
  • 4 Center for Basic Technology Research, The Tokyo Metropolitan Institute of Medical Science, Tokyo 113-8613, Japan. , (Japan)
  • 5 Department of Obstetrics and Gynecology, National Hospital Organization, Sagamihara National Hospital, Kanagawa 252-0392, Japan; and. , (Japan)
  • 6 Clinical Research Center for Allergy and Rheumatology, National Hospital Organization, Sagamihara National Hospital, Kanagawa 252-0392, Japan. , (Japan)
Type
Published Article
Journal
The Journal of Immunology
Publisher
The American Association of Immunologists
Publication Date
Jan 01, 2018
Volume
200
Issue
1
Pages
92–100
Identifiers
DOI: 10.4049/jimmunol.1602113
PMID: 29180489
Source
Medline
License
Unknown

Abstract

The NFAT family transcription factors play crucial roles in immunological and other biological activities. NFAT3 is rarely expressed in T cells, and the mechanisms and significance of the specific NFAT3 downregulation in T cells have been unknown. In human CD4+ T cells, overexpression of NFAT1 and NFAT3 enhanced and suppressed IL-2 expression, respectively. NFAT3 downregulation in Jurkat cells using RNA interference technology augmented IL-2 expression, whereas a knockdown of NFAT1, NFAT2, and NFAT4 suppressed it. The promoter/enhancer activity of the NFAT-binding site in the IL-2 gene was upregulated and downregulated by NFAT1 and NFAT3, respectively. A study employing NFAT1/NFAT3 chimeric molecules revealed that the region in NFAT3 responsible for NFAT promoter activity inhibition was located within its N-terminal transactivation domain, Ca2+-regulatory domain, and DNA-binding domain. Downregulation of NFAT3 expression in T cells is mediated by lower chromatin accessibility and enhancer activity in its promoter in comparison with aortic smooth muscle cells expressing endogenous NFAT3. The binding sites of T-box transcription factor TBX5 and NK-2 transcription factor-related locus 5 Nkx2.5, which were expressed at higher levels in aortic smooth muscle cells than in T cells, were located within the -387 to +97 NFAT3 promoter region, exhibiting the maximum enhancer activity. Mutating the binding site of TBX5 but not Nkx2.5 diminished the NFAT3 promoter activity, whereas the overexpression of TBX5 enhanced it. Introduction of TBX5 into CD4+ T cells enhanced the expression of NFAT3 and suppressed that of IL-2. TBX5 deficiency-mediated downregulation of NFAT3 is crucial for the high cytokine-producing activity of T cells.

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