Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, People's Republic of China.
Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, People's Republic of China.
Vascul Pharmacol. 2021 Feb;136:106821. doi: 10.1016/j.vph.2020.106821. Epub 2020 Nov 19.
Vascular calcification (VC) is associated with the high morbidity and mortality of cardiovascular diseases in dialysis patients and is a process in which vascular smooth muscle cells (VSMCs) actively differentiate into osteoblast-like cells. Reticulocalbin-2 (RCN2) is involved in the process of osteogenic differentiation under diabetic conditions, but its regulatory role under hyperphosphatemic conditions and the related mechanisms remain unclear. In this study, the importance of the interactions among RCN2, STAT3 and miR-155-5p during the osteogenic differentiation and calcification of human aortic VSMCs (HASMCs) were investigated.
RCN2 was measured in femoropopliteal artery plaque specimens from 6 peripheral arterial disease (PAD) patients with chronic kidney disease (CKD) and 6 PAD patients without CKD. RCN2 protein and mRNA expression were assessed in the high phosphate-induced aortic rings culture ex vivo model. In vitro calcification assays and molecular mechanism studies were performed in HASMCs.
Immunohistochemical staining results revealed increased RCN2 expression in the calcified plaques of femoral arteries of patients with CKD and in a high phosphate-induced aortic culture ex vivo model. RCN2 promoted HASMCs osteogenic differentiation and calcification by inducing STAT3 phosphorylation. Furthermore, inhibition of STAT3 activation by cryptotanshinone (CT) promoted miR-155-5p expression in HASMCs. In turn, miR-155-5p inhibited RCN2 mRNA expression, while RCN2 overexpression partially offset the miR-155-5p-mediated inhibition of HASMC calcification, acting as a positive feedback loop.
These results demonstrate that RCN2 is a crucial regulator of VC under hyperphosphatemic conditions. RCN2/STAT3/miR-155-5p feedback loop is important in VC and targeting each member of this feedback loop could potentially reverse high phosphate-induced VC.
血管钙化（VC）与透析患者心血管疾病的高发病率和死亡率相关，是血管平滑肌细胞（VSMCs）主动向成骨样细胞分化的过程。网状钙结合蛋白-2（RCN2）参与糖尿病条件下成骨分化过程，但在高磷条件下的调节作用及其相关机制尚不清楚。在这项研究中，研究了 RCN2、STAT3 和 miR-155-5p 之间的相互作用在人主动脉平滑肌细胞（HASMCs）成骨分化和钙化过程中的重要性。
在 6 例伴有慢性肾脏病（CKD）的外周动脉疾病（PAD）患者和 6 例无 CKD 的 PAD 患者的股浅动脉斑块标本中测量 RCN2。在高磷诱导的主动脉环体外培养模型中评估 RCN2 蛋白和 mRNA 表达。在 HASMCs 中进行体外钙化测定和分子机制研究。
免疫组化染色结果显示，CKD 患者股动脉钙化斑块和高磷诱导的主动脉体外培养模型中 RCN2 表达增加。RCN2 通过诱导 STAT3 磷酸化促进 HASMCs 成骨分化和钙化。此外， cryptotanshinone（CT）抑制 STAT3 激活促进 HASMCs 中 miR-155-5p 的表达。反过来，miR-155-5p 抑制 RCN2 mRNA 表达，而 RCN2 过表达部分抵消了 miR-155-5p 介导的 HASMC 钙化抑制作用，作为正反馈环。
这些结果表明，RCN2 是高磷条件下 VC 的关键调节因子。RCN2/STAT3/miR-155-5p 反馈环在 VC 中很重要，靶向该反馈环的每个成员可能逆转高磷诱导的 VC。
