SPP1 and Hypertension: VSMC phenotypic transformation is characterized by an increase in synthetic protein including OPN and a reduction in contractile proteins such as α-smooth muscle actin (α-SMA) and smooth muscle 22α (SM22α) in hypertension.15, 16 Contractile proteins α-SMA and SM22α were downregulated, while synthetic protein osteopontin (OPN) were upregulated, indicating phenotypic transformation in aortic media of SHR (Figure 1f).