miR-19a: an effective regulator of SOCS3 and enhancer of JAK-STAT signalling

PLoS One. 2013 Jul 22;8(7):e69090. doi: 10.1371/journal.pone.0069090. Print 2013.

Abstract

Suppressors of cytokine signalling (SOCS) proteins are classic inhibitors of the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway. Many cytokines and pathogenic mediators induce expression of SOCS, which act in a negative feedback loop to inhibit further signal transduction. SOCS mRNA expression is regulated by DNA binding of STAT proteins, however, their post-transcriptional regulation is poorly understood. microRNAs (miRNAs) are small non-coding RNAs that bind to complementary sequences on target mRNAs, often silencing gene expression. miR-19a has been shown to regulate SOCS1 expression during mutiple myeloma and be induced by the anti-viral cytokine interferon-(IFN)-α, suggesting a role in the regulation of the JAK-STAT pathway. This study aimed to identify targets of miR-19a in the JAK-STAT pathway and elucidate the functional consequences. Bioinformatic analysis identified highly conserved 3'UTR miR-19a target sequences in several JAK-STAT associated genes, including SOCS1, SOCS3, SOCS5 and Cullin (Cul) 5. Functional studies revealed that miR-19a significantly decreased SOCS3 mRNA and protein, while a miR-19a antagomir specifically reversed its inhibitory effect. Furthermore, miR-19a-mediated reduction of SOCS3 enhanced IFN-α and interleukin (IL)-6 signal transduction through STAT3. These results reveal a novel mechanism by which miR-19a may augment JAK-STAT signal transduction via control of SOCS3 expression and are fundamental to the understanding of inflammatory regulation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Cell Line
  • Humans
  • Interferon-alpha / pharmacology
  • Interleukin-1 / pharmacology
  • Janus Kinases / metabolism*
  • MicroRNAs / genetics*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Reproducibility of Results
  • STAT Transcription Factors / metabolism*
  • Signal Transduction / drug effects
  • Signal Transduction / genetics*
  • Suppressor of Cytokine Signaling 3 Protein
  • Suppressor of Cytokine Signaling Proteins / genetics*

Substances

  • Interferon-alpha
  • Interleukin-1
  • MIRN19 microRNA, human
  • MicroRNAs
  • RNA, Messenger
  • SOCS3 protein, human
  • STAT Transcription Factors
  • Suppressor of Cytokine Signaling 3 Protein
  • Suppressor of Cytokine Signaling Proteins
  • Janus Kinases

Grant support

This study was supported by the Health Research Board (www.hrb.ie) (RP/2007/278, TRA/2007/14 and PD/2008/33). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. No additional external funding was received for this study.