Tian et al. confirmed that Ang II interacts with angiotensin type 2 receptor (AT2R) to stimulate ROS production in H9C2 cells and up-regulated CyPA expression [53]; Su et al. found that melatonin reduces Ang II-induced ROS production and cardiac hypertrophy in H9C2 cells by inhibiting the CyPA/EMMPRIN pathway [54]. Here, PPIA is linked to cardiac hypertrophy.