Natriuretic peptide receptor-C-mediated attenuation of vascular smooth muscle cell hypertrophy involves Gqα/PLCβ1 proteins and ROS-associated signaling.

Hypertension is associated with vascular remodeling due to hyperproliferation and hypertrophy of vascular smooth muscle cells (VSMC). Recently, we showed the implication of enhanced expression of Gqα and PLCβ1 proteins in hypertrophy of VSMCs from 16-week-old spontaneously hypertensive rats (SHR). The aim of this study was to investigate whether C-ANP , a natriuretic peptide receptor-C (NPR-C) ligand that was shown to inhibit vasoactive peptide-induced enhanced protein synthesis in A10 VSMC could also attenuate hypertrophy of VSMC isolated from rat model of cardiac hypertrophy and to further explore the possible involvement of Gqα/PLCβ1 proteins and ROS-mediated signaling in this effect. The protein synthesis and cell volume, markers of hypertrophy were significantly enhanced in VSMC from 16-week-old SHR compared with age-matched WKY rats and C-ANP treatment attenuated both to WKY levels. In addition, C-ANP treatment also attenuated the enhanced expression of AT1 receptor, Gqα, PLCβ1, Nox4, and p47 proteins, the enhanced activation of EGFR, PDGFR, IGF-1R, enhanced phosphorylation of ERK1/2/AKT and c-Src in VSMC from SHR. Furthermore, the enhanced levels of superoxide anion and NADPH oxidase activity exhibited by VSMC from SHR were also attenuated to control levels by C-ANP treatment. These results indicate that C-ANP via the activation of NPR-C attenuates VSMC hypertrophy through decreasing the overexpression of Gqα/PLCβ1 proteins, enhanced oxidative stress, increased activation of growth factor receptors, and enhanced phosphorylation of MAPK/AKT signaling pathways. Thus, it can be suggested that C-ANP may be used as a therapeutic agent for the treatment of vascular complications associated with hypertension and atherosclerosis.