PT  - JOURNAL ARTICLE
AU  - Hongyan Sui
AU  - Jun Yang
AU  - Xiaojun Hu
AU  - Qian Chen
AU  - Tomozumi Imamichi
TI  - siRNA containing a unique 5-nucleotide motif acts as a quencher of IFI16-mediated innate immune response
AID  - 10.1101/564872
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 564872
4099  - http://biorxiv.org/content/early/2019/03/01/564872.short
4100  - http://biorxiv.org/content/early/2019/03/01/564872.full
AB  - We previously reported that small interfering RNA (siRNA) enhances DNA or DNA virus mediated-interferon (IFN)-λ1 induction through retinoic acid-inducible gene I (RIG-I) and interferon gamma-inducible protein 16 (IFI16) crosstalk-signalling pathway. Here we provide further evidence of a new role for siRNA. siRNA containing a 5-nucleotide (nt) motif sequence suppresses DNA-mediated IFNs and inflammatory cytokines. We determined that motif siRNA inhibits the induction when the motif is located at the 3’ or 5’-terminus of siRNA. Using THP1-Lucia ISG cells with various DNA stimulants, it is demonstrated that motif siRNA inhibits DNA or DNA virus but not RNA virus-mediated signaling. Motif siRNA specifically interrupts IFI16 binding to DNA and has 2.5-fold higher affinity to IFI16 than that of siRNA without the motif. Collectively, these findings may shed lights on a novel function of siRNA with the 5-nt motif as a quencher of innate immunity and facilitate the development of potential therapeutics to treat diseases in which this pathway is dysregulated.