Calcitonin gene-related peptide attenuates angiotensin II-induced ROS-dependent apoptosis in vascular smooth muscle cells by inhibiting the CaMKII/CREB signalling pathway.

Apoptosis is associated with various cardiovascular diseases. CGRP exerts a variety of effects within the cardiovascular system, and protects against the onset and development of angiotensin (Ang) II-induced vascular dysfunction and remodelling. However, it is not known whether CGRP has a direct effect on Ang II-induced apoptosis in vascular smooth muscle cells (VSMCs), and the mechanism underlying the anti-apoptotic role remains unclear. In this study, CGRP significantly suppressed reactive oxygen species (ROS) and apoptosis in Ang II-induced VSMCs. In VSMCs pre-treated with a CGRP receptor antagonist (CGRP8-37), the CGRP-mediated inhibition of Ang II-induced ROS and apoptosis was completely abolished. Moreover, pre-treatment with N-acetyl-L cysteine (NAC), an ROS scavenger, blocked the effects of CGRP on Ang II-induced apoptosis. In addition, the activation of CaMKII and the downstream transcription factor CREB stimulated by Ang II was abrogated by CGRP. Importantly, in both CGRP and NAC-treated VSMCs, CGRP failed to further attenuate CaMKII and CREB activation. The results demonstrate that CGRP attenuated Ang II-induced ROS-dependent apoptosis in VSMCs by inhibiting the CaMKII/CREB signalling pathway.