The Upregulation of Genomic Imprinted DLK1-Dio3 miRNAs in Murine Lupus Is Associated with Global DNA Hypomethylation

PLoS One. 2016 Apr 12;11(4):e0153509. doi: 10.1371/journal.pone.0153509. eCollection 2016.

Abstract

Epigenetic factors such as DNA methylation and microRNAs (miRNAs) are now increasingly recognized as vital contributors to lupus etiology. In this study, we investigated the potential interaction of these two epigenetic factors in lupus-prone MRL-lpr mice. We recently reported dysregulated expression of miRNAs in splenocytes of MRL-lpr mice. Here, we report that a majority of the upregulated miRNAs in MRL-lpr mice is located at the genomic imprinted DLK1-Dio3 domain. Further, we show a differential magnitude of upregulation of DLK1-Dio3 miRNA cluster in purified splenic CD4+ T, CD19+ B, and splenic CD4-CD19- cells from MRL-lpr lupus mice when compared to control MRL mice. MRL-lpr splenocytes (especially CD19+ and CD4-CD19- subsets) were hypomethylated compared to cells from control, MRL mice. We further show that deliberate demethylation of splenocytes from control MRL mice, but not from MRL-lpr lupus mice, with specific DNA methylation inhibitor 5-Aza-2'-deoxycytidine significantly augmented DLK1-Dio3 miRNAs expression. These findings strongly indicate that the upregulation of DLK1-Dio3 miRNAs in lupus splenic cell subsets is associated with reduced global DNA methylation levels in lupus cells. There was a differential upregulation of DLK-Dio3 miRNAs among various demethylated splenic cell subsets, which implies varied sensitivity of DLK1-Dio3 miRNA cluster in these cell subsets to DNA hypomethylation. Finally, inhibition of select DLK1-Dio3 miRNA such as miR-154, miR-379 and miR-300 with specific antagomirs significantly reduced the production of lupus-relevant IFNγ, IL-1β, IL-6, and IL-10 in lipopolysaccharide (LPS) activated splenocytes from MRL-lpr mice. Our study is the first to show that DNA methylation regulates genomic imprinted DLK1-Dio3 miRNAs in autoimmune lupus, which suggests a connection of DNA methylation, miRNA and genomic imprinting in lupus pathogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium-Binding Proteins
  • Cytokines / metabolism
  • DNA Methylation*
  • Genetic Predisposition to Disease / genetics
  • Genomic Imprinting*
  • Intercellular Signaling Peptides and Proteins / genetics*
  • Iodide Peroxidase / genetics*
  • Lupus Erythematosus, Systemic / genetics*
  • Lupus Erythematosus, Systemic / immunology
  • Lupus Erythematosus, Systemic / metabolism
  • Mice
  • Mice, Inbred MRL lpr
  • MicroRNAs / genetics*
  • Spleen / immunology
  • Spleen / metabolism
  • Up-Regulation / genetics*

Substances

  • Calcium-Binding Proteins
  • Cytokines
  • Dlk1 protein, mouse
  • Intercellular Signaling Peptides and Proteins
  • MicroRNAs
  • iodothyronine deiodinase type III
  • Iodide Peroxidase

Grants and funding

This work was supported by Virginia-Maryland College of Veterinary Medicine (VMCVM, http://www.vetmed.vt.edu/) Intramural Research Competition Grant (IRC 175185) and Alliance for Lupus Research (ALR, http://www.lupusresearch.org/; Award ID: 219631). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.