학술논문
N.sup.6-methyladenosine modification of HIV-1 RNA suppresses type-I interferon induction in differentiated monocytic cells and primary macrophages
Research Article
Research Article
Document Type
Report
Author
Source
PLoS Pathogens. March 10, 2021, Vol. 17 Issue 3, e1009421
Subject
Language
English
ISSN
1553-7366
Abstract
Author(s): Shuliang Chen 1, Sameer Kumar 2, Constanza E. Espada 2, Nagaraja Tirumuru 1, Michael P. Cahill 2, Lulu Hu 3, Chuan He 3,4, Li Wu 2,* Introduction Transcriptional modification [...]
N.sup.6 -methyladenosine (m.sup.6 A) is a prevalent RNA modification that plays a key role in regulating eukaryotic cellular mRNA functions. RNA m.sup.6 A modification is regulated by two groups of cellular proteins, writers and erasers that add or remove m.sup.6 A, respectively. HIV-1 RNA contains m.sup.6 A modifications that modulate viral infection and gene expression in CD4.sup.+ T cells. However, it remains unclear whether m.sup.6 A modifications of HIV-1 RNA modulate innate immune responses in myeloid cells that are important for antiviral immunity. Here we show that m.sup.6 A modification of HIV-1 RNA suppresses the expression of antiviral cytokine type-I interferon (IFN-I) in differentiated human monocytic cells and primary monocyte-derived macrophages. Transfection of differentiated monocytic U937 cells with HIV-1 RNA fragments containing a single m.sup.6 A-modification significantly reduced IFN-I mRNA expression relative to their unmodified RNA counterparts. We generated HIV-1 with altered m.sup.6 A levels of RNA by manipulating the expression of the m.sup.6 A erasers (FTO and ALKBH5) or pharmacological inhibition of m.sup.6 A addition in virus-producing cells, or by treating HIV-1 RNA with recombinant FTO in vitro. HIV-1 RNA transfection or viral infection of differentiated U937 cells and primary macrophages demonstrated that HIV-1 RNA with decreased m.sup.6 A levels enhanced IFN-I expression, whereas HIV-1 RNA with increased m.sup.6 A modifications had opposite effects. Our mechanistic studies indicated that m.sup.6 A of HIV-1 RNA escaped retinoic acid-induced gene I (RIG-I)-mediated RNA sensing and activation of the transcription factors IRF3 and IRF7 that drive IFN-I gene expression. Together, these findings suggest that m.sup.6 A modifications of HIV-1 RNA evade innate immune sensing in myeloid cells.
N.sup.6 -methyladenosine (m.sup.6 A) is a prevalent RNA modification that plays a key role in regulating eukaryotic cellular mRNA functions. RNA m.sup.6 A modification is regulated by two groups of cellular proteins, writers and erasers that add or remove m.sup.6 A, respectively. HIV-1 RNA contains m.sup.6 A modifications that modulate viral infection and gene expression in CD4.sup.+ T cells. However, it remains unclear whether m.sup.6 A modifications of HIV-1 RNA modulate innate immune responses in myeloid cells that are important for antiviral immunity. Here we show that m.sup.6 A modification of HIV-1 RNA suppresses the expression of antiviral cytokine type-I interferon (IFN-I) in differentiated human monocytic cells and primary monocyte-derived macrophages. Transfection of differentiated monocytic U937 cells with HIV-1 RNA fragments containing a single m.sup.6 A-modification significantly reduced IFN-I mRNA expression relative to their unmodified RNA counterparts. We generated HIV-1 with altered m.sup.6 A levels of RNA by manipulating the expression of the m.sup.6 A erasers (FTO and ALKBH5) or pharmacological inhibition of m.sup.6 A addition in virus-producing cells, or by treating HIV-1 RNA with recombinant FTO in vitro. HIV-1 RNA transfection or viral infection of differentiated U937 cells and primary macrophages demonstrated that HIV-1 RNA with decreased m.sup.6 A levels enhanced IFN-I expression, whereas HIV-1 RNA with increased m.sup.6 A modifications had opposite effects. Our mechanistic studies indicated that m.sup.6 A of HIV-1 RNA escaped retinoic acid-induced gene I (RIG-I)-mediated RNA sensing and activation of the transcription factors IRF3 and IRF7 that drive IFN-I gene expression. Together, these findings suggest that m.sup.6 A modifications of HIV-1 RNA evade innate immune sensing in myeloid cells.