List of the 2,653 DEGs indicated in S8C Fig.

Angiotensin-II (Ang-II) drives pathological vascular wall remodeling in hypertension and abdominal aortic aneurysm (AAA) through mechanisms that are not completely understood. Previous studies showed that the phosphatase activity of calcineurin (Cn) mediates Ang-II-induced AAA, but the cell type involved in the action of Cn in AAA formation remained unknown. Here, by employing newly created smooth muscle cell (SMC)-specific and endothelial cell (EC)-specific Cn-deficient mice (SM-Cn−/− and EC-Cn−/− mice), we show that Cn expressed in SMCs, but not ECs, was required for Ang-II-induced AAA. Unexpectedly, SMC Cn also played a structural role in the early onset and maintenance of Ang-II-induced hypertension, independently of its known phosphatase activity. Among the signaling pathways activated by Ang-II, Cn signaling is essential in SMCs, as nearly 90% of the genes regulated by Ang-II in the aorta required Cn expression in SMCs. Cn orchestrated, independently of its enzymatic activity, the induction by Ang-II of a transcriptional program closely related to SMC contractility and hypertension. Cn deletion in SMCs, but not its pharmacological inhibition, impaired the regulation of arterial contractility. Among the genes whose regulation by Ang-II required Cn expression but not its phosphatase activity, we discovered that Serpine1 was critical for Ang-II-induced hypertension. Indeed, pharmacological inhibition of PAI-1, the protein encoded by Serpine1, impaired SMCs contractility and readily regressed hypertension. Mechanistically, Serpine1 induction was mediated by Smad2 activation via the structural role of Cn. These findings uncover an unexpected role for Cn in vascular pathophysiology and highlight PAI-1 as a potential therapeutic target for hypertension.

血管紧张素II（Angiotensin-II，Ang-II）可通过尚未完全阐明的机制介导高血压与腹主动脉瘤（abdominal aortic aneurysm，AAA）患者的病理性血管壁重塑。既往研究表明，钙调神经磷酸酶（calcineurin，Cn）的磷酸酶活性可介导Ang-II诱导的腹主动脉瘤形成，但钙调神经磷酸酶在腹主动脉瘤发生中发挥作用的细胞类型仍未明确。本研究通过构建全新的平滑肌细胞（smooth muscle cell，SMC）特异性及内皮细胞（endothelial cell，EC）特异性钙调神经磷酸酶敲除小鼠（SM-Cn-/-与EC-Cn-/-小鼠），证实仅平滑肌细胞表达的钙调神经磷酸酶（而非内皮细胞来源的钙调神经磷酸酶）是Ang-II诱导腹主动脉瘤形成所必需的。出乎意料的是，平滑肌细胞来源的钙调神经磷酸酶还可在Ang-II诱导的高血压发生早期及病程维持阶段发挥结构性作用，且这一功能不依赖其已被阐明的磷酸酶活性。在Ang-II激活的多条信号通路中，钙调神经磷酸酶信号通路在平滑肌细胞中至关重要：主动脉中近90%受Ang-II调控的基因均依赖平滑肌细胞的钙调神经磷酸酶表达。钙调神经磷酸酶可不依赖其酶活性，协同Ang-II诱导出与平滑肌细胞收缩功能及高血压发生密切相关的转录程序。仅敲除平滑肌细胞中的钙调神经磷酸酶（而非通过药理学手段抑制其活性），即可损害动脉收缩功能的调控。在那些受Ang-II调控时依赖钙调神经磷酸酶表达但不依赖其磷酸酶活性的基因中，我们发现丝氨酸蛋白酶抑制剂E1（Serpine1）对Ang-II诱导的高血压至关重要。事实上，针对Serpine1编码的纤溶酶原激活物抑制剂-1（PAI-1）进行药理学抑制，可损害平滑肌细胞收缩性并快速逆转高血压。机制层面的研究表明，Serpine1的诱导是通过钙调神经磷酸酶的结构性作用介导Smad2蛋白激活实现的。本研究揭示了钙调神经磷酸酶在血管病理生理过程中此前未被发现的作用，并将PAI-1确立为高血压潜在的治疗靶点。