RATIONALE PCSKs (Proprotein convertase subtilisins/kexins) are a protease family with unknown functions in vasculature. Previously, we demonstrated PCSK6 upregulation in human atherosclerotic plaques associated with smooth muscle cells (SMCs), inflammation, extracellular matrix remodeling, and mitogens. OBJECTIVE Here, we applied a systems biology approach to gain deeper insights into the PCSK6 role in normal and diseased vessel wall. METHODS AND RESULTS Genetic analyses revealed association of intronic PCSK6 variant rs1531817 with maximum internal carotid intima-media thickness progression in high-cardiovascular risk subjects. This variant was linked with PCSK6 mRNA expression in healthy aortas and plaques but also with overall plaque SMA+ cell content and pericyte fraction. Increased PCSK6 expression was found in several independent human cohorts comparing atherosclerotic lesions versus healthy arteries, using transcriptomic and proteomic datasets. By immunohistochemistry, PCSK6 was localized to fibrous cap SMA+ cells and neovessels in plaques. In human, rat, and mouse intimal hyperplasia, PCSK6 was expressed by proliferating SMA+ cells and upregulated after 5 days in rat carotid balloon injury model, with positive correlation to PDGFB (platelet-derived growth factor subunit B) and MMP (matrix metalloprotease) 2/MMP14. Here, PCSK6 was shown to colocalize and cointeract with MMP2/MMP14 by in situ proximity ligation assay. Microarrays of carotid arteries from Pcsk6-/- versus control mice revealed suppression of contractile SMC markers, extracellular matrix remodeling enzymes, and cytokines/receptors. Pcsk6-/- mice showed reduced intimal hyperplasia response upon carotid ligation in vivo, accompanied by decreased MMP14 activation and impaired SMC outgrowth from aortic rings ex vivo. PCSK6 silencing in human SMCs in vitro leads to downregulation of contractile markers and increase in MMP2 expression. Conversely, PCSK6 overexpression increased PDGFBB (platelet-derived growth factor BB)-induced cell proliferation and particularly migration. CONCLUSIONS PCSK6 is a novel protease that induces SMC migration in response to PDGFB, mechanistically via modulation of contractile markers and MMP14 activation. This study establishes PCSK6 as a key regulator of SMC function in vascular remodeling. Visual Overview: An online visual overview is available for this article.

中文翻译：

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PCSK6是控制血管重塑中平滑肌细胞功能的关键蛋白酶。

RATIONALE PCSK（前蛋白转化酶枯草杆菌蛋白酶/ kexins）是一种蛋白酶家族，在血管系统中功能未知。以前，我们在与平滑肌细胞（SMC），炎症，细胞外基质重塑和促分裂原有关的人动脉粥样硬化斑块中证明了PCSK6上调。目的在这里，我们应用了系统生物学方法来深入了解PCSK6在正常和患病血管壁中的作用。方法和结果遗传分析显示，在高心血管风险受试者中，内含PCSK6变体rs1531817与最大内部颈动脉内膜中层厚度进展有关。该变异与健康主动脉和斑块中PCSK6 mRNA的表达有关，但也与斑块的SMA +细胞含量和周细胞分数有关。使用转录组学和蛋白质组学数据集，在比较动脉粥样硬化病变与健康动脉的几个独立的人类队列中，发现PCSK6表达增加。通过免疫组织化学，将PCSK6定位于斑块中的纤维帽SMA +细胞和新血管。在人，大鼠和小鼠的内膜增生中，PCSK6通过增殖的SMA +细胞表达，并在大鼠颈动脉球囊损伤模型中5天后上调，与PDGFB（血小板衍生的生长因子亚基B）和MMP（基质金属蛋白酶）2呈正相关。 / MMP14。在这里，通过原位邻近结扎法显示，PCSK6与MMP2 / MMP14共定位并共同相互作用。Pcsk6-/-与对照小鼠相比，颈动脉微阵列显示出收缩性SMC标记，细胞外基质重塑酶和细胞因子/受体的抑制。Pcsk6-/-小鼠在体内经颈动脉结扎后显示出内膜增生反应减少，同时伴有MMP14激活减少和离体从主动脉环的SMC增生受损。体外人SMC中PCSK6沉默导致收缩标志物的下调和MMP2表达的增加。相反，PCSK6过表达会增加PDGFBB（血小板衍生的生长因子BB）诱导的细胞增殖，尤其是迁移。结论PCSK6是一种新型蛋白酶，可通过调节收缩标志物和激活MMP14来机械诱导PDGFB对SMC的迁移。这项研究建立了PCSK6作为SMC在血管重塑中的关键调节因子。视觉概述：本文提供了在线视觉概述。伴有MMP14激活减少和离体从主动脉环的SMC增生受损。体外人SMC中PCSK6沉默导致收缩标志物的下调和MMP2表达的增加。相反，PCSK6过表达会增加PDGFBB（血小板衍生的生长因子BB）诱导的细胞增殖，尤其是迁移。结论PCSK6是一种新型蛋白酶，可通过调节收缩标志物和激活MMP14来机械诱导PDGFB对SMC的迁移。这项研究建立了PCSK6作为SMC在血管重塑中的关键调节因子。视觉概述：本文提供了在线视觉概述。伴有MMP14激活降低和离体从主动脉环的SMC增生受损。体外人SMC中PCSK6沉默导致收缩标志物的下调和MMP2表达的增加。相反，PCSK6过表达会增加PDGFBB（血小板衍生的生长因子BB）诱导的细胞增殖，尤其是迁移。结论PCSK6是一种新型蛋白酶，可通过调节收缩标志物和激活MMP14来机械诱导PDGFB对SMC的迁移。这项研究建立了PCSK6作为SMC在血管重塑中的关键调节因子。视觉概述：本文提供了在线视觉概述。体外人SMC中PCSK6沉默导致收缩标志物的下调和MMP2表达的增加。相反，PCSK6过表达会增加PDGFBB（血小板衍生的生长因子BB）诱导的细胞增殖，尤其是迁移。结论PCSK6是一种新型蛋白酶，可通过调节收缩标志物和激活MMP14来机械诱导PDGFB对SMC的迁移。这项研究建立了PCSK6作为SMC在血管重塑中的关键调节因子。视觉概述：本文提供了在线视觉概述。体外人SMC中PCSK6沉默导致收缩标志物的下调和MMP2表达的增加。相反，PCSK6过表达会增加PDGFBB（血小板衍生的生长因子BB）诱导的细胞增殖，尤其是迁移。结论PCSK6是一种新型蛋白酶，可通过调节收缩标志物和激活MMP14来机械诱导PDGFB对SMC的迁移。这项研究建立了PCSK6作为SMC在血管重塑中的关键调节因子。视觉概述：本文提供了在线视觉概述。通过调节收缩标志物和MMP14激活机制。这项研究建立了PCSK6作为SMC在血管重塑中的关键调节因子。视觉概述：本文提供了在线视觉概述。通过调节收缩标志物和MMP14激活机制。这项研究建立了PCSK6作为SMC在血管重塑中的关键调节因子。视觉概述：本文提供了在线视觉概述。