Ni Huaner, Haemmig Stefan, Deng Yihuan, Chen Jingshu, Simion Viorel, Yang Dafeng, Sukhova Galina, Shvartz Eugenia, Wara A K M Khyrul, Cheng Henry S, Pérez-Cremades Daniel, Assa Carmel, Sausen Grasiele, Zhuang Rulin, Dai Qiuyan, Feinberg Mark W
Department of Medicine, Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA (H.N., S.H., Y.D., J.C., V.S., D.Y., G. Sukhova, E.S., A.K.M.K.W., H.S.C., D.P.-C., C.A., G. Sausen, R.Z., M.W.F.).
Department of Cardiology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, China (H.N., Q.D.).
Arterioscler Thromb Vasc Biol. 2021 Sep;41(9):2399-2416. doi: 10.1161/ATVBAHA.120.315911. Epub 2021 Jul 22.
Vascular smooth muscle cell (VSMC) plasticity plays a critical role in the development of atherosclerosis. Long noncoding RNAs (lncRNAs) are emerging as important regulators in the vessel wall and impact cellular function through diverse interactors. However, the role of lncRNAs in regulating VSMCs plasticity and atherosclerosis remains unclear.
We identified a VSMC-enriched lncRNA cardiac mesoderm enhancer-associated noncoding RNA (CARMN) that is dynamically regulated with progression of atherosclerosis. In both mouse and human atherosclerotic plaques, CARMN colocalized with VSMCs and was expressed in the nucleus. Knockdown of CARMN using antisense oligonucleotides in Ldlr−/− mice significantly reduced atherosclerotic lesion formation by 38% and suppressed VSMCs proliferation by 45% without affecting apoptosis. In vitro CARMN gain- and loss-of-function studies verified effects on VSMC proliferation, migration, and differentiation. TGF-β1 (transforming growth factor-beta) induced CARMN expression in a Smad2/3-dependent manner. CARMN regulated VSMC plasticity independent of the miR143/145 cluster, which is located in close proximity to the CARMN locus. Mechanistically, lncRNA pulldown in combination with mass spectrometry analysis showed that the nuclear-localized CARMN interacted with SRF (serum response factor) through a specific 600–1197 nucleotide domain. CARMN enhanced SRF occupancy on the promoter regions of its downstream VSMC targets. Finally, knockdown of SRF abolished the regulatory role of CARMN in VSMC plasticity.
The lncRNA CARMN is a critical regulator of VSMC plasticity and atherosclerosis. These findings highlight the role of a lncRNA in SRF-dependent signaling and provide implications for a range of chronic vascular occlusive disease states.
血管平滑肌细胞（VSMC）可塑性在动脉粥样硬化发展中起关键作用。长链非编码RNA（lncRNA）正成为血管壁中的重要调节因子，并通过多种相互作用分子影响细胞功能。然而，lncRNA在调节VSMC可塑性和动脉粥样硬化中的作用仍不清楚。
我们鉴定出一种在VSMC中富集的lncRNA——心脏中胚层增强子相关非编码RNA（CARMN），其随动脉粥样硬化进展而动态调节。在小鼠和人类动脉粥样硬化斑块中，CARMN与VSMC共定位并在细胞核中表达。在Ldlr−/−小鼠中使用反义寡核苷酸敲低CARMN可使动脉粥样硬化病变形成显著减少38%，并使VSMC增殖抑制45%，而不影响细胞凋亡。体外CARMN功能获得和缺失研究证实了其对VSMC增殖、迁移和分化的影响。转化生长因子-β1（TGF-β1）以Smad2/3依赖的方式诱导CARMN表达。CARMN独立于位于CARMN基因座附近的miR143/145簇调节VSMC可塑性。机制上，lncRNA下拉结合质谱分析表明，核定位的CARMN通过一个特定的600 - 1197核苷酸结构域与血清反应因子（SRF）相互作用。CARMN增强了SRF在其下游VSMC靶基因启动子区域的结合。最后，敲低SRF消除了CARMN在VSMC可塑性中的调节作用。
lncRNA CARMN是VSMC可塑性和动脉粥样硬化的关键调节因子。这些发现突出了lncRNA在SRF依赖信号传导中的作用，并为一系列慢性血管闭塞性疾病状态提供了启示。
