Lou Chuang, Li Tao
Department of Cardiology, AnKang Hospital of Traditional Chinese Medicine, Ankang, China.
Arch Med Sci. 2020 Nov 16;19(1):180-188. doi: 10.5114/aoms.2020.97991. eCollection 2023.
Long non-coding RNAs (lncRNAs) constitute a growing class of non-coding genes with diverse cellular function. Recent studies have reported that lncRNA smooth muscle and endothelial cell-enriched (SENCR) was associated with the phenotype switch of vascular smooth muscle cells and participated in vascular homeostasis. However, the potential role of SENCR in endothelial-to-mesenchymal transition (EndMT) and the underlying mechanism remain unknown.
Human carotid plaque samples and human coronary endothelial cells (HACECs) were collected to examine the expression of SENCR. Quantitative PCR and immunoblots were performed to evaluate the expression of SENCR and miR-126a in HACECs in response to TGF-β1 and transfected with small interfering RNA.
We found that SENCR was significantly decreased in carotid plaques as compared to normal carotids. Knockdown of SENCR in HACECs aggravated the expression of smooth muscle markers α-SMA and calponin induced by TGF-β1 but repressed the expression of endothelial markers platelet/endothelial cell adhesion molecule 1 (PECAM1) and VE-cadherin down-regulated by TGF-β1. Through bioinformatic analysis and Luciferase assay, miR-126a was identified as the direct target of SENCR. Further mechanistic experiments revealed that overexpression of miR-126a bound to the 3'UTR region of SMURF2 and inhibited the expression of SMURF2, which was considered as the negative regulator of TGF-β/Smad signaling. Finally, overexpression of miR-126a did not restore the decreased expression of the smooth muscle markers α-SMA and calponin under the condition of SMURF2 depletion, suggesting that the effect of miR-126a on EndMT progression is SMURF2 dependent.
SENCR alleviates TGF-β-induced EndMT and sponges miR-126a expression via direct inhibition of the negative regulator of TGF-β/Smad signaling SMURF2.
长链非编码RNA（lncRNA）构成了一类不断增多的具有多种细胞功能的非编码基因。最近的研究报道，富含平滑肌和内皮细胞的lncRNA（SENCR）与血管平滑肌细胞的表型转换有关，并参与血管稳态。然而，SENCR在内皮-间充质转化（EndMT）中的潜在作用及其潜在机制仍不清楚。
收集人颈动脉斑块样本和人冠状动脉内皮细胞（HACEC），检测SENCR的表达。进行定量PCR和免疫印迹，以评估HACEC中SENCR和miR-126a在响应转化生长因子-β1（TGF-β1）并转染小干扰RNA后的表达。
我们发现，与正常颈动脉相比，颈动脉斑块中SENCR显著降低。在HACEC中敲低SENCR会加重TGF-β1诱导的平滑肌标志物α-平滑肌肌动蛋白（α-SMA）和钙调蛋白的表达，但会抑制TGF-β1下调的内皮标志物血小板/内皮细胞黏附分子1（PECAM1）和血管内皮钙黏蛋白（VE-钙黏蛋白）的表达。通过生物信息学分析和荧光素酶测定，miR-126a被鉴定为SENCR的直接靶点。进一步的机制实验表明，miR-126a的过表达与SMAD特异性E3泛素蛋白连接酶2（SMURF2）的3'非翻译区（3'UTR）区域结合并抑制SMURF2的表达，SMURF2被认为是TGF-β/ Smad信号通路的负调节因子。最后，在SMURF2缺失的情况下，miR-126a的过表达并未恢复平滑肌标志物α-SMA和钙调蛋白降低的表达，这表明miR-126a对EndMT进展的影响依赖于SMURF2。
SENCR通过直接抑制TGF-β/ Smad信号通路的负调节因子SMURF2来减轻TGF-β诱导的EndMT并抑制miR-126a的表达。
