Licl2

K562 cell line was cultured in RPMI (Thermo Fisher, Waltham, Massachusetts) with 10% FCS. Th 10058-F4 inhibitor (Sigma Aldrich) was used at a concentration of 64 µM during 48 h, whereas LiCl₂ (Sigma Aldrich, Saint Louis, Missouri) was used at a concentration 10 mM for 24 h. After incubation, viability and proliferation of the cells were evaluated with trypan blue (Supplementary Figure S4). Cells were then collected for RNA extraction.

The extraction of dsRNA was performed at the MRC-DPRU and involved a method previously described by Nyaga et al. (2018)^{53 (link)}. Briefly, a 100 mg stool sample was added to 200 µL freshly made phosphate buffered saline (PBS) (Sigma-Aldrich, Germany). A 900 µL volume of TRI-REAGENT-LS (Molecular Research Center, Inc, Cincinnati, OH, USA) was added to the suspended stool sample to homogenize as well as lyse the cells and cell components. A volume of 300 µL chloroform (Sigma-Aldrich, Germany) was then added and centrifugation (13,000 rpm for 20 min at 4 °C) was done in a temperature-controlled microcentrifuge (Eppendorf centrifuge 5427R, Hamburg, Germany). The supernatant containing the total RNA was precipitated by addition of 700 µL isopropanol (Sigma-Aldrich, Germany) and by centrifugation at 16,000×g for 30 min at room temperature. The resulting pellet was re-dissolved by addition of 90 µL of ddH20 (Merck KGaA, Germany). A concentration of 8 M LiCl₂ (Sigma, St. Louis, MO, USA) was used to remove ssRNA through precipitation for 16 h after which further centrifugation was done for 30 min at 16,000×g. The extracted dsRNA was purified by utilizing the MinElute gel extraction kit (Qiagen, Hilden, Germany) and the integrity and enrichment of the dsRNA was verified via agarose gel electrophoresis.