Department of Cardiology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China.
Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China.
Int J Mol Med. 2019 Apr;43(4):1597-1610. doi: 10.3892/ijmm.2019.4090. Epub 2019 Feb 4.
The current study aimed to clarify the role of nucleolin in the phenotypic transformation of vascular smooth muscle cells (VSMCs) and to preliminarily explore its underlying mechanism. The spatial and temporal expression patterns of nucleolin, and the effects of angiotensin II (Ang II) on the expression of VSMC phenotypic transformation markers, α‑smooth muscle‑actin, calponin, smooth muscle protein 22α and osteopontin were investigated. The effects of nucleolin on VSMC phenotypic transformation and the expression of phenotypic transformation‑associated genes, tropoelastin, epiregulin and fibroblast growth factor 2 (b‑FGF), were determined. Protein‑RNA co‑immunoprecipitation was used to investigate the potential target genes regulated by the nucleolin in phenotypic transformation of VSMCs. Finally, the stability of tropoelastin mRNA and the effects of nucleolin on the expression of tropoelastin were assayed. The results revealed that Ang II significantly promoted the phenotypic transformation of VSMCs. The expression of nucleolin was gradually upregulated in VSMCs treated with Ang II at different concentrations for various durations. Ang II induced nucleolin translocation from the nucleus to cytoplasm. Additionally, Ang II significantly promoted the phenotypic transformation of VSMCs. Overexpression and silencing of nucleolin regulated the expressions of tropoelastin, epiregulin and b‑FGF. There was an interaction between tropoelastin mRNA and nucleolin protein, promoting the stability of tropoelastin mRNA and enhancing the expression of tropoelastin at the protein level. Upregulation of nucleolin had an important role in Ang II‑induced VSMC phenotypic transformation, and its underlying mechanism may be through interacting with tropoelastin mRNA, leading to its increased stability and protein expression. The findings provide a new perspective into the regulatory mechanism of VSMC phenotypic transformation.
本研究旨在阐明核仁素在血管平滑肌细胞（VSMC）表型转化中的作用，并初步探讨其潜在机制。研究了核仁素的时空表达模式，以及血管紧张素 II（Ang II）对 VSMC 表型转化标志物α-平滑肌肌动蛋白、钙调蛋白、平滑肌蛋白 22α 和骨桥蛋白表达的影响。研究了核仁素对 VSMC 表型转化和表型转化相关基因原肌球蛋白、表皮调节素和碱性成纤维细胞生长因子 2（b-FGF）表达的影响。采用蛋白-RNA 免疫共沉淀技术研究核仁素在 VSMC 表型转化中潜在的靶基因。最后，检测了原肌球蛋白 mRNA 的稳定性以及核仁素对原肌球蛋白表达的影响。结果表明，Ang II 显著促进了 VSMC 的表型转化。在不同浓度 Ang II 处理不同时间的 VSMC 中，核仁素的表达逐渐上调。Ang II 诱导核仁素从细胞核向细胞质移位。此外，Ang II 显著促进了 VSMC 的表型转化。核仁素的过表达和沉默调节了原肌球蛋白、表皮调节素和 b-FGF 的表达。原肌球蛋白 mRNA 与核仁素蛋白之间存在相互作用，促进了原肌球蛋白 mRNA 的稳定性，并增强了原肌球蛋白蛋白水平的表达。核仁素的上调在 Ang II 诱导的 VSMC 表型转化中起重要作用，其潜在机制可能是通过与原肌球蛋白 mRNA 相互作用，导致其稳定性增加和蛋白表达增强。研究结果为 VSMC 表型转化的调控机制提供了新视角。
