STAT3 and cardiac hypertrophy: Besides, Ang II activates STAT3, which interacts with TLR4 and increases IL-6, and, in turn, promotes the second STAT3 activation, leading to an upregulated expression of genes for cardiac hypertrophy through the IL-6/glycoprotein 130 (gp130)/Janus-family tyrosine kinases 2 (JAK2) pathway (52).