List of the 271 DEGs indicated in Fig 7C.

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，参与高血压及腹主动脉瘤（abdominal aortic aneurysm，AAA）中的病理性血管壁重构。既往研究证实，钙调神经磷酸酶（calcineurin，Cn）的磷酸酶活性介导了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过程中发挥作用所涉及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），证实平滑肌细胞而非内皮细胞表达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不依赖其已知磷酸酶活性的前提下，对Ang-II诱导的高血压的早期发生及病情维持发挥结构性作用。在Ang-II激活的诸多信号通路中，钙调神经磷酸酶信号通路在平滑肌细胞中至关重要：主动脉内近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。钙调神经磷酸酶可独立于其酶促活性，调控Ang-II诱导的、与平滑肌细胞收缩功能及高血压密切相关的转录程序。仅敲除平滑肌细胞的钙调神经磷酸酶（而非通过药理学手段抑制其活性），会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Serpine1对Ang-II诱导的高血压至关重要。事实上，靶向抑制Serpine1编码的蛋白PAI-1，可损伤平滑肌细胞的收缩功能并快速逆转高血压。从机制层面而言，Serpine1的诱导是通过钙调神经磷酸酶的结构性作用，经Smad2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的意外新功能，并将PAI-1确立为高血压的潜在治疗靶点。