The siRNAs targeting the longer FTH1 isoform (FTH1-L) or total FTH1 transcripts were transfected into THP-1 macrophages 24 hours prior to Mtb infection, and FTH1 mRNA levels (Figure 2A) and protein abundance were assessed at 24- and 48-hours post-infection (Figure 2B). Here, FTH1 is linked to infection.