A new microRNA signal pathway regulated by long noncoding RNA TGFB2-OT1 in autophagy and inflammation of vascular endothelial cells

Abstract

TGFB2-OT1 (TGFB2 overlapping transcript 1) is a newly discovered long noncoding RNA (lncRNA) derived from the 3'UTR of TGFB2. It can regulate autophagy in vascular endothelial cells (VECs). However, the mechanisms of TGFB2-OT1 action are unclear, and whether it is involved in VECs dysfunction needs investigation. Here, the level of TGFB2-OT1 was markedly increased by lipopolysaccharide and oxidized low-density lipoprotein, 2 VECs inflammation triggers. A chemical small molecule, 3-benzyl-5-((2-nitrophenoxy) methyl)-dihydrofuran-2(3H)-one (3BDO) significantly decreased TGFB2-OT1 levels and inhibited the effect of LPS and oxLDL. The NUPR1 level was upregulated by the 2 inflammation inducers and modulated the TGFB2-OT1 level by promoting the expression of TIA1, responsible for TGFB2-OT1 processing. We focused on how TGFB2-OT1 regulated autophagy and inflammation. Use of miRNA chip assay, TGFB2-OT1 overexpression technology and 3BDO revealed that TGFB2-OT1 regulated the levels of 3 microRNAs, MIR3960, MIR4488 and MIR4459. Further studies confirmed that TGFB2-OT1 acted as a competing endogenous RNA, bound to MIR3960, MIR4488 and MIR4459, then regulated the expression of the miRNA targets CERS1 (ceramide synthase 1), NAT8L (N-acetyltransferase 8-like [GCN5-related, putative]), and LARP1 (La ribonucleoprotein domain family, member 1). CERS1 and NAT8L participate in autophagy by affecting mitochondrial function. TGFB2-OT1 increased the LARP1 level, which promoted SQSTM1 (sequestosome 1) expression, NFKB RELA and CASP1 activation, and then production of IL6, IL8 and IL1B in VECs. Thus, NUPR1 and TIA1 may control the level of TGFB2-OT1, and TGFB2-OT1 bound to MIR3960, MIR4488 and MIR4459, which targeted CERS1, NAT8L, and LARP1, respectively, the key proteins involved in autophagy and inflammation.

LncRNA as a Therapeutic Target for Angiogenesis

“…Microarray profiling of the overexpression of TGFβ2-OT1 indicates that three miRNAs (miR-3960, miR-4488 and miR-4459) are regulated by TGFβ2-OT1 and acts as an endogenous competing RNA bound to miRNAs [65]. Furthermore, the overexpression of these three miRNAs resulted in the repression of their downstream targets: ceramide synthase 1 (CERS1), N-acetyltransferase 8-like (NAT8L), and La-ribonucleoprotein-domain-family-member 1 (LARP1) [66]. These are primarily involved in endothelial cell autophagy, inflammation and in endothelial injury, and regulation of angiogenesis [65, 66].…”

“…Furthermore, the overexpression of these three miRNAs resulted in the repression of their downstream targets: ceramide synthase 1 (CERS1), N-acetyltransferase 8-like (NAT8L), and La-ribonucleoprotein-domain-family-member 1 (LARP1) [66]. These are primarily involved in endothelial cell autophagy, inflammation and in endothelial injury, and regulation of angiogenesis [65, 66]. Another study reported that smooth muscle specific osteogenic transcription factor RUNX2 is regulated by TGFβ and bone morphogenic protein (BMP) [67].…”

Long non-coding RNAs act as regulators of cell autophagy in diseases

“…Acting as a ceRNA, FLJ11812 competed for binding with miR-4459, resulting in the increase of its target Atg13 and promotion of autophagy (38). Apart from miR-4459, FLJ11812 also acts as the molecular decoy of miR-3960 and miR-4488, elevating the expression of miRNA targets ceramide synthase 1 (CERS1) and N-acetyltransferase 8-like (NAT8L), respectively, two molecules participating in mitophagy (39). In addition, phospholipase D (PLD) inhibitor stimulates cell autophagy and exhibits attractive antitumorigenic effects by destabilizing mTOR.…”

Inhibition of LncRNA-HRIM Increases Cell Viability by Regulating Autophagy Levels During Hypoxia/Reoxygenation in Myocytes

“…Meanwhile, the downregulation of MEG3 increases cell proliferation in bladder cancer by activating autophagy [33]. Lnc-RNA-TGFB2-OT1, as a competing endogenous RNA, regulates autophagy and inflammation in vascular endothelial cells by binding to MIR3960, MIR4488, and MIR4459[34]. In addition, LncRNA-APF (autophagy promoting factor) regulates miR-188-3p and affects autophagic cell death and myocardial infarction [35].…”