Identification of a novel MTOR activator and discovery of a competing endogenous RNA regulating autophagy in vascular endothelial cells

Autophagy. 2014 Jun;10(6):957-71. doi: 10.4161/auto.28363.

Abstract

MTOR, a central regulator of autophagy, is involved in cancer and cardiovascular and neurological diseases. Modulating the MTOR signaling balance could be of great significance for numerous diseases. No chemical activators of MTOR have been found, and the urgent challenge is to find novel MTOR downstream components. In previous studies, we found a chemical small molecule, 3-benzyl-5-((2-nitrophenoxy) methyl)-dihydrofuran-2(3H)-one (3BDO), that inhibited autophagy in human umbilical vein endothelial cells (HUVECs) and neuronal cells. Here, we found that 3BDO activated MTOR by targeting FKBP1A (FK506-binding protein 1A, 12 kDa). We next used 3BDO to detect novel factors downstream of the MTOR signaling pathway. Activation of MTOR by 3BDO increased the phosphorylation of TIA1 (TIA1 cytotoxic granule-associated RNA binding protein/T-cell-restricted intracellular antigen-1). Finally, we used gene microarray, RNA interference, RNA-ChIP assay, bioinformatics, luciferase reporter assay, and other assays and found that 3BDO greatly decreased the level of a long noncoding RNA (lncRNA) derived from the 3' untranslated region (3'UTR) of TGFB2, known as FLJ11812. TIA1 was responsible for processing FLJ11812. Further experiments results showed that FLJ11812 could bind with MIR4459 targeting ATG13 (autophagy-related 13), and ATG13 protein level was decreased along with 3BDO-decreased FLJ11812 level. Here, we provide a new activator of MTOR, and our findings highlight the role of the lncRNA in autophagy.

Keywords: ATG13; MIR4459; MTOR activator; TIA1; autophagy; lncRNA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3' Untranslated Regions
  • 4-Butyrolactone / analogs & derivatives*
  • 4-Butyrolactone / pharmacology
  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism
  • Autophagy / drug effects
  • Autophagy / genetics
  • Autophagy / physiology*
  • Autophagy-Related Proteins
  • Enzyme Activation / drug effects
  • Human Umbilical Vein Endothelial Cells
  • Humans
  • MicroRNAs / genetics
  • MicroRNAs / metabolism
  • Models, Molecular
  • Phosphorylation
  • Poly(A)-Binding Proteins / metabolism
  • RNA, Long Noncoding / genetics
  • RNA, Long Noncoding / metabolism*
  • Ribosomal Protein S6 Kinases, 70-kDa / metabolism
  • Signal Transduction / drug effects
  • Sirolimus / pharmacology
  • T-Cell Intracellular Antigen-1
  • TOR Serine-Threonine Kinases / metabolism*
  • Tacrolimus Binding Proteins / chemistry
  • Tacrolimus Binding Proteins / metabolism
  • Transforming Growth Factor beta2 / genetics
  • Transforming Growth Factor beta2 / metabolism

Substances

  • 3' Untranslated Regions
  • 3-benzyl-5-((2-nitrophenoxy)methyl)dihydrofuran-2(3H)-one
  • ATG13 protein, human
  • Adaptor Proteins, Signal Transducing
  • Autophagy-Related Proteins
  • FKBP1A protein, human
  • MicroRNAs
  • Poly(A)-Binding Proteins
  • RNA, Long Noncoding
  • T-Cell Intracellular Antigen-1
  • TGFB2 protein, human
  • TIA1 protein, human
  • Transforming Growth Factor beta2
  • MTOR protein, human
  • TOR Serine-Threonine Kinases
  • Ribosomal Protein S6 Kinases, 70-kDa
  • ribosomal protein S6 kinase, 70kD, polypeptide 1
  • Tacrolimus Binding Proteins
  • 4-Butyrolactone
  • Sirolimus