Defects in IL-2R Signaling Contribute to Diminished Maintenance of FOXP3 Expression in CD4+CD25+ Regulatory T-Cells of Type 1 Diabetic Subjects

• Published in: Diabetes (New York, N.Y.) Vol. 59; no. 2; pp. 407 - 415
• Main Authors: Long, S. Alice, Cerosaletti, Karen, Bollyky, Paul L., Tatum, Megan, Shilling, Heather, Zhang, Sheng, Zhang, Zhong-Yin, Pihoker, Catherine, Sanda, Srinath, Greenbaum, Carla, Buckner, Jane H.
• Format: Journal Article
• Language: English
• Published: United States American Diabetes Association 01.02.2010
• Subjects: Adolescent; Adult; Aged; Blotting, Western; CD4 Antigens - immunology; CD4-Positive T-Lymphocytes - drug effects; CD4-Positive T-Lymphocytes - immunology; Cell Culture Techniques; Diabetes Mellitus, Type 1 - genetics; Diabetes Mellitus, Type 1 - immunology; Female; Flow Cytometry; Forkhead Transcription Factors - genetics; Humans; Interleukin-2 - immunology; Interleukin-2 - pharmacology; Interleukin-2 Receptor alpha Subunit - immunology; Interleukin-7 - pharmacology; Lymphocyte Activation; Male; Middle Aged; Original; Reference Values; Signal Transduction; T-Lymphocytes, Regulatory - cytology; T-Lymphocytes, Regulatory - drug effects; T-Lymphocytes, Regulatory - immunology; Young Adult
• ISSN: 0012-1797; 1939-327X; 1939-327X
• DOI: 10.2337/db09-0694

Defects in IL-2R Signaling Contribute to Diminished Maintenance of FOXP3 Expression in CD4 + CD25 + Regulatory T-Cells of Type 1 Diabetic Subjects S. Alice Long 1 , Karen Cerosaletti 1 , Paul L. Bollyky 1 , Megan Tatum 1 , Heather Shilling 1 , Sheng Zhang 2 , Zhong-Yin Zhang 2 , Catherine Pihoker 3 , Srinath Sanda 1 , Carla Greenbaum 1 and Jane H. Buckner 1 1 Benaroya Research Institute at Virginia Mason, Seattle, Washington; 2 Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana; 3 Seattle Children's Hospital, Seattle, Washington. Corresponding author: Jane H. Buckner, jbuckner{at}benaroyaresearch.org . Abstract OBJECTIVE In humans, multiple genes in the interleukin (IL)-2/IL-2 receptor (IL-2R) pathway are associated with type 1 diabetes. However, no link between IL-2 responsiveness and CD4 + CD25 + FOXP3 + regulatory T-cells (Tregs) has been demonstrated in type 1 diabetic subjects despite the role of these IL-2–dependent cells in controlling autoimmunity. Here, we address whether altered IL-2 responsiveness impacts persistence of FOXP3 expression in Tregs of type 1 diabetic subjects. RESEARCH DESIGN AND METHODS Persistence of Tregs was assessed by culturing sorted CD4 + CD25 hi natural Tregs with IL-2 and measuring FOXP3 expression over time by flow cytometry for control and type 1 diabetic populations. The effects of IL-2 on FOXP3 induction were assessed 48 h after activation of CD4 + CD25 − T-cells with anti-CD3 antibody. Cytokine receptor expression and signaling upon exposure to IL-2, IL-7, and IL-15 were determined by flow cytometry and Western blot analysis. RESULTS Maintenance of FOXP3 expression in CD4 + CD25 + Tregs of type 1 diabetic subjects was diminished in the presence of IL-2, but not IL-7. Impaired responsiveness was not linked to altered expression of the IL-2R complex. Instead, IL-2R signaling was reduced in Tregs and total CD4 + T-cells of type 1 diabetic subjects. In some individuals, decreased signal transducer and activator of transcription 5 phosphorylation correlated with significantly higher expression of protein tyrosine phosphatase N2, a negative regulator of IL-2R signaling. CONCLUSIONS Aberrant IL-2R signaling in CD4 + T-cells of type 1 diabetic subjects contributes to decreased persistence of FOXP3 expression that may impact establishment of tolerance. These findings suggest novel targets for treatment of type 1 diabetes within the IL-2R pathway and suggest that an altered IL-2R signaling signature may be a biomarker for type 1 diabetes. Footnotes The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. Received May 8, 2009. Accepted October 16, 2009. © 2010 by the American Diabetes Association.