MIR208A: MIR208A is a microRNA that has been found in isolated exosomes of patients with lung cancer and has been shown to modulate radioresistance in recipient cells [11]. Exosomal miRNAs have also been found to have dose-related effects during thoracic radiation treatment [PMC6525830]. Primers from QIAGEN® were used to detect the expression of miR499, MIR208A, and U6 [PMC7957261]. In the context of acute myocardial infarction, MIR208A expression is increased in circulating exosomes and may affect bone marrow stem cells [PMC9501315]. In a study on cardiac development, MIR208A expression levels were found to be upregulated in day 10 populations compared to day 6 populations [PMC6828809]. MIR208A is involved in the switch from Myh6 to Myh7 isoforms during hypertrophy and is required for this shift under conditions of mechanical stress and hypothyroidism [PMC5586433]. The inactivation of MIR208A by antagomir-208a was demonstrated by co-transfecting miR-208a + antagomir-208a + GFP-PDE4D3′UTR into HEK cells without altering GFP expression [PMC5105063]. Gain of MIR208A function through transfection of miR-208a has been shown to increase levels of cAMP and PKA, supporting its involvement in the cAMP/PKA signaling pathway [PMC5105063]. Additionally, MIR208A may play a role in cardiac fibrosis formation in congenital heart disease as well as acquired heart disease [PMC3879305]. The myogenic miRNAs including MIR1-1, MIR133A1, MIR208A, and MIR499A are expressed by day 10 during pluripotent stem cell differentiation into the cardiac lineage [PMC6828809].