Ribonuclease L mediates the cell-lethal phenotype of double-stranded RNA editing enzyme ADAR1 deficiency in a human cell line

Abstract

ADAR1 isoforms are adenosine deaminases that edit and destabilize double-stranded RNA reducing its immunostimulatory activities. Mutation of ADAR1 leads to a severe neurodevelopmental and inflammatory disease of children, Aicardi-Goutiéres syndrome. In mice, Adar1 mutations are embryonic lethal but are rescued by mutation of the Mda5 or Mavs genes, which function in IFN induction. However, the specific IFN regulated proteins responsible for the pathogenic effects of ADAR1 mutation are unknown. We show that the cell-lethal phenotype of ADAR1 deletion in human lung adenocarcinoma A549 cells is rescued by CRISPR/Cas9 mutagenesis of the RNASEL gene or by expression of the RNase L antagonist, murine coronavirus NS2 accessory protein. Our result demonstrate that ablation of RNase L activity promotes survival of ADAR1 deficient cells even in the presence of MDA5 and MAVS, suggesting that the RNase L system is the primary sensor pathway for endogenous dsRNA that leads to cell death.DOI: http://dx.doi.org/10.7554/eLife.25687.001

Zika Virus Production Is Resistant to RNase L Antiviral Activity

“…OAS3 generates 2=,5=-phosphodiester-linked oligoadenylates (2-5A) from ATP, which bind RNase L to trigger homodimerization and nucleolytic activation (20). This results in a milieu of antiviral effects, including protein translation inhibition as a result of cellular rRNA (rRNA) and mRNA degradation and inhibition of viral replication and translation due to viral ssRNA cleavage, as well as the induction of inflammation (21) and apoptosis (22)(23)(24). This pathway is highly effective in inhibiting replication of RNA and DNA viruses, and previous findings from our lab revealed that virus resistance to RNase L activity can dictate cellular tropism (25,26), valuable information in the context of ZIKV.…”

Real-time 2-5A kinetics suggest that interferons β and λ evade global arrest of translation by RNase L

“…In human cells, 2-5A is synthesized by three enzymes: oligoadenylate synthetase 1 (OAS1), OAS2, and OAS3 (OASs), which function as cytosolic dsRNA sensors using dsRNA binding for activation (6,7). The activity of the OASs is normally low to allow for housekeeping protein synthesis, but it increases in the presence of viral or host dsRNA molecules (8). 2-5A has an antiviral effect, against which some viruses have evolved 2-5A antagonist genes that are essential for infection (9)(10)(11)(12)(13)(14)(15)(16).…”

“…The 2-5A system is also a surveillance pathway for endogenous double-stranded RNAs (dsRNAs) from mammalian genomes. Cells with adenosine deaminase 1 deficiency accumulate self-dsRNA that promotes 2-5A-driven apoptosis (8). 2-5A synthesis in the presence of low amounts of endogenous dsRNAs does not cause cell death, but rather functions as a suppressor of adhesion, proliferation, migration, and prostate cancer metastasis (17,18).…”

In vitro assays and techniques utilized in anticancer drug discovery

“…Determination of S‐nitrosylated proteins has been carried out in a study reported by Kao, Wu, Hu, and Kong () to investigate the protective effects of curcumin in lipopolysaccharide induced by macrophage cells (Raw264.7). Effect of 2‐acetylamino‐3‐[4‐(2‐acetylamino‐2‐carboxyethylsulfanylcarbonylamino) phenyl carbamoylsulfanyl] propionic acid, a novel GST inhibitor, on the induction of thiol oxidative stress in esophageal cancer cell lines (KYSE‐450, TE‐13 and KYSE‐510) has been evaluated using S ‐glutathionylation by Li, Banerjee, et al ().…”