Identification of microRNA-31 as a novel regulator contributing to impaired interleukin-2 production in T cells from patients with systemic lupus erythematosus

Arthritis Rheum. 2012 Nov;64(11):3715-25. doi: 10.1002/art.34596.

Abstract

Objective: MicroRNAs (miRNAs) function to fine-tune the control of immune cell signaling. It is well established that there are abnormalities in the interleukin-2 (IL-2)-related signaling pathways in systemic lupus erythematosus (SLE). The miR-31 microRNA has been found to be markedly underexpressed in patients with SLE, and thus the present study was undertaken to investigate the role of miR-31 in IL-2 defects in lupus T cells.

Methods: Expression levels of miR-31 were quantitated using TaqMan miRNA assays. Transfection and stimulation of cultured cells followed by TaqMan quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, and reporter gene assays were conducted to determine the biologic function of miR-31. NF-AT nuclear translocation and expression were quantitatively measured using an ImageStream cytometer. Bioinformatics analysis, small interfering RNA (siRNA) knockdown, and Western blotting were performed to validate miR-31 targets and effects.

Results: The expression of miR-31 was significantly decreased in lupus T cells, and this was positively correlated with the expression of IL-2. Overexpression of miR-31 in T cells increased the production of IL-2 by altering NF-AT nuclear expression and IL2 promoter activity, while knockdown of endogenous miR-31 reduced IL-2 production. RhoA expression was directly repressed by miR-31 in T cells. Of note, siRNA-mediated knockdown of RhoA enhanced IL2 promoter activity and, consequently, up-regulated IL-2 production. RhoA expression was consistently up-regulated and negatively correlated with the levels of miR-31 in lupus T cells. Manipulation of miR-31 expression in lupus T cells restored the expression of IL-2 at both the messenger RNA and protein levels.

Conclusion: MicroRNA-31 is a novel enhancer of IL-2 production during T cell activation. Dysregulation of miR-31 and its target, RhoA, could be a novel molecular mechanism underlying the IL-2 deficiency in patients with SLE.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Gene Expression Regulation / genetics
  • Gene Expression Regulation / immunology
  • Humans
  • Interleukin-2 / deficiency
  • Interleukin-2 / genetics*
  • Interleukin-2 / immunology
  • Jurkat Cells
  • Lupus Erythematosus, Systemic / genetics*
  • Lupus Erythematosus, Systemic / immunology*
  • Lupus Erythematosus, Systemic / metabolism
  • MicroRNAs / immunology*
  • NFATC Transcription Factors / genetics
  • NFATC Transcription Factors / immunology
  • Primary Cell Culture
  • Promoter Regions, Genetic / genetics
  • Promoter Regions, Genetic / immunology
  • RNA, Small Interfering / genetics
  • Signal Transduction / genetics
  • Signal Transduction / immunology
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / metabolism
  • rhoA GTP-Binding Protein / genetics
  • rhoA GTP-Binding Protein / immunology

Substances

  • IL2 protein, human
  • Interleukin-2
  • MIRN31 microRNA, human
  • MicroRNAs
  • NFATC Transcription Factors
  • RNA, Small Interfering
  • rhoA GTP-Binding Protein