Center for Molecular and Translational Cardiology, Heidelberg University Hospital, 69120 Heidelberg, Germany.
Circ Res. 2013 Jan 4;112(1):66-78. doi: 10.1161/CIRCRESAHA.112.275156. Epub 2012 Oct 9.
Mice lacking the EF-hand Ca2+ sensor S100A1 display endothelial dysfunction because of distorted Ca2+ -activated nitric oxide (NO) generation.
To determine the pathophysiological role of S100A1 in endothelial cell (EC) function in experimental ischemic revascularization.
Patients with chronic critical limb ischemia showed almost complete loss of S100A1 expression in hypoxic tissue. Ensuing studies in S100A1 knockout (SKO) mice subjected to femoral artery resection unveiled insufficient perfusion recovery and high rates of autoamputation. Defective in vivo angiogenesis prompted cellular studies in SKO ECs and human ECs, with small interfering RNA-mediated S100A1 knockdown demonstrating impaired in vitro and in vivo proangiogenic properties (proliferation, migration, tube formation) and attenuated vascular endothelial growth factor (VEGF)-stimulated and hypoxia-stimulated endothelial NO synthase (eNOS) activity. Mechanistically, S100A1 deficiency compromised eNOS activity in ECs by interrupted stimulatory S100A1/eNOS interaction and protein kinase C hyperactivation that resulted in inhibitory eNOS phosphorylation and enhanced VEGF receptor-2 degradation with attenuated VEGF signaling. Ischemic SKO tissue recapitulated the same molecular abnormalities with insufficient in vivo NO generation. Unresolved ischemia entailed excessive VEGF accumulation in SKO mice with aggravated VEGF receptor-2 degradation and blunted in vivo signaling through the proangiogenic phosphoinositide-3-kinase/Akt/eNOS cascade. The NO supplementation strategies rescued defective angiogenesis and salvaged limbs in SKO mice after femoral artery resection.
Our study shows for the first time downregulation of S100A1 expression in patients with critical limb ischemia and identifies S100A1 as critical for EC function in postnatal ischemic angiogenesis. These findings link its pathological plasticity in critical limb ischemia to impaired neovascularization, prompting further studies to probe the microvascular therapeutic potential of S100A1.
缺乏 EF 手型钙离子传感器 S100A1 的小鼠由于钙离子激活的一氧化氮（NO）生成受损而表现出内皮功能障碍。
确定 S100A1 在实验性缺血再血管化过程中内皮细胞（EC）功能的病理生理作用。
慢性严重肢体缺血患者的缺氧组织中 S100A1 表达几乎完全丧失。随后对 S100A1 敲除（SKO）小鼠进行股动脉切除术的研究显示，再灌注恢复不足和高截肢率。体内血管生成缺陷促使 SKO EC 和人 EC 进行细胞研究，小干扰 RNA 介导的 S100A1 敲低显示体外和体内促血管生成特性（增殖、迁移、管形成）受损，以及血管内皮生长因子（VEGF）刺激和缺氧刺激的内皮一氧化氮合酶（eNOS）活性减弱。机制上，S100A1 缺乏通过中断刺激 S100A1/eNOS 相互作用和蛋白激酶 C 过度激活来损害 EC 中的 eNOS 活性，导致 eNOS 磷酸化抑制和 VEGF 受体-2 降解增强，VEGF 信号减弱。缺血性 SKO 组织再现了相同的分子异常，体内 NO 生成不足。未解决的缺血导致 SKO 小鼠中 VEGF 积累过多，VEGF 受体-2 降解加剧，体内通过促血管生成的磷酸肌醇-3-激酶/Akt/eNOS 级联信号减弱。NO 补充策略挽救了 SKO 小鼠股动脉切除后的缺陷性血管生成和肢体挽救。
我们的研究首次显示，严重肢体缺血患者 S100A1 表达下调，并确定 S100A1 对出生后缺血性血管生成中 EC 功能至关重要。这些发现将其在严重肢体缺血中的病理性可塑性与血管新生受损联系起来，促使进一步研究探索 S100A1 的微血管治疗潜力。
