miR‐9‐mimic and miR‐9 agomir preparation

miR‐9‐mimic and a scramble control, NC‐mimic, were purchased from Genscript (Shanghai, China). miR‐9‐mimic is an artificial, chemically modified double‐stranded miRNA, which mimics the mature endogenous miR‐9 after being transfected into cells with concentration of 100 μg·mL⁻¹. Both miR‐9‐mimic and NC‐mimic were suspended in 0.9% NaCl to a final storage concentration of 10 mg·mL⁻¹.

The miR‐9 agomir is a double‐stranded RNA analog of mature miR‐9 which has been chemically modified and conjugated to a cholesterol moiety to promote specificity and stability for assays. For treatment in vivo, agomiR‐9 (RiboBio, Guangdong, China) was injected intravenously into the tail vein at a dose of 1 nmol (diluted in 20 μL PBS) per mouse three days before EV71 infection.