Citation
- Authors: Oteiza, A., Mechti, N.
- Year: 2015
- Journal: J Interferon Cytokine Res 35 859-74
- Applications: in vitro / DNA, siRNA / INTERFERin, jetPEI
- Cell types:
- Name: HEK-293T
Description: Human embryonic kidney Fibroblast
Known as: HEK293T, 293T - Name: HeLa
Description: Human cervix epitheloid carcinoma cells
- Name: HEK-293T
Abstract
Activation of innate immune response, induced after the recognition of double-stranded RNA (dsRNA), formed during replication of most viruses, results in intracellular signaling cascades ultimately culminating in the expression of type I interferon (IFN). In this study, we provide the first evidence that FoxO4 triggers the activation of the innate immune signaling pathway in coupling stimulation of TLR3 and RIG-like receptors by the synthetic dsRNA analog, poly(I:C), to IFN-beta and IFN-induced gene induction, whereas knockdown of FoxO4 had opposite effects. Similar effects of FoxO4 were observed during paramyxovirus-mediated IFN-beta transcriptional induction. We further found that knockdown of FoxO4 did not affect IRF3 and NF-kappaB activation by poly(I:C), suggesting that FoxO4 would act downstream in the signaling pathway. In addition, we show that the IFN-induced TRIM22 ubiquitin ligase targets FoxO4 and antagonizes its activity through an unrelated ubiquitin/autophagosomic-lysosomal pathway. Unexpectedly, TRIM22 knockdown strongly sensitizes cells to dsRNA-induced caspase-dependent apoptosis, as early as 2 h after poly(I:C) stimulation, concomitantly to the inhibition of the expression of the antiapoptotic protein, Bcl-2, indicating that TRIM22 might be a key factor for controlling the cell survival after TLR3 stimulation. Taken together, our data demonstrate that the regulation of FoxO4 protein expression and cell survival by TRIM22 controls TLR3-mediated IFN type I gene induction, preventing excessive antiviral response through dsRNA-induced apoptosis.