STAT3 and infection: We then further investigated whether TFRC affected STAT3 expression in cardiomyocytes, and found that overexpression of TFRC in cardiomyocytes by AAV9‐flag‐TFRC infection significantly increased STAT3 and phosphroylated STAT3 (p‐STAT3) expression (Figure 3A), and Ccl2 mRNA expression (Figure 3B).