Down Regulated lncRNA MEG3 Eliminates Mycobacteria in Macrophages via Autophagy

Sci Rep. 2016 Jan 13;6:19416. doi: 10.1038/srep19416.

Abstract

Small non-coding RNA play a major part in host response to bacterial agents. However, the role of long non-coding RNA (lncRNA) in this context remains unknown. LncRNA regulate gene expression by acting e.g. as transcriptional coactivators, RNA decoys or microRNA sponges. They control development, differentiation and cellular processes such as autophagy in disease conditions. Here, we provide an insight into the role of lncRNA in mycobacterial infections. Human macrophages were infected with Mycobacterium bovis BCG and lncRNA expression was studied early post infection. For this purpose, lncRNA with known immune related functions were preselected and a lncRNA specific RT-qPCR protocol was established. In addition to expression-based prediction of lncRNA function, we assessed strategies for thorough normalisation of lncRNA. Arrayed quantification showed infection-dependent repression of several lncRNA including MEG3. Pathway analysis linked MEG3 to mTOR and PI3K-AKT signalling pointing to regulation of autophagy. Accordingly, IFN-γ induced autophagy in infected macrophages resulted in sustained MEG3 down regulation and lack of IFN-γ allowed for counter regulation of MEG3 by viable M. bovis BCG. Knockdown of MEG3 in macrophages resulted in induction of autophagy and enhanced eradication of intracellular M. bovis BCG.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Autophagy / drug effects
  • Autophagy / genetics
  • Caspase 3 / metabolism
  • Cell Line
  • Cells, Cultured
  • Cluster Analysis
  • Gene Expression Profiling
  • Gene Expression Regulation* / drug effects
  • Gene Knockdown Techniques
  • Humans
  • Interferon-gamma / pharmacology
  • Macrophages / drug effects
  • Macrophages / microbiology*
  • Macrophages / physiology*
  • Microbial Viability
  • Microtubule-Associated Proteins / metabolism
  • Mycobacterium bovis / physiology*
  • RNA, Long Noncoding / genetics*
  • Time Factors

Substances

  • MEG3 non-coding RNA, human
  • Microtubule-Associated Proteins
  • RNA, Long Noncoding
  • light chain 3, human
  • Interferon-gamma
  • Caspase 3