Regulation of pmiRGLO-3′-UTR-COVID-19 plasmid expression by selected microRNAs in HEK293T cells and cell viability after transfection. Cells were transiently co-transfected with control or reporter constructs and selected microRNA mimics or the negative control microRNA. (A) Firefly/Renilla luminescence ratio showed that hsa-miR-3941, hsa-miR-128-1-5p, hsa-miR-4433b-3p, and hsa-miR-365b-5p, as well as hsa-miR-138-5p, significant decreased the expression of pmiRGLO-3′-UTR-COVID-19 related to the expression of negative control mimic (paired Student’s t test, one-tailed p-value < 0.05 after Bonferroni correction). ** indicates a p-value < 0.01 and *** p-value < 0.001; (B) On the other hand, MTT assay data showed that empty pmiRGLO or pmiRGLO-3′-UTR-COVID-19 plasmids and mimics did not produce any significant cytotoxic effect related to DharmaFECT after 24 h of co-transfection (paired Student’s t test). Graph represents the mean ± SD of, at least, three experiments. An extended figure with all experimental replicate data points is available in Figure S1.