STAT3 and fatty liver disease: Calo et al. found that a liver-specific miR-21 removal decreased hepatic steatosis in mice fed a high-fat (HFD) diet through the regulation of transcription factors, including forkhead box protein O1 (FOXO1), forkhead box protein A2 (FOXA2), HNF4α, the signal transducer and activator of transcription 3 (STAT3), and insulin-induced gene 2 (INSIG2) [55].