Division of Cardiac Surgery, St. Michael's Hospital, Toronto, Ontario, Canada; Keenan Research Centre in the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.
University of Ottawa Heart Institute, Ottawa, Ontario, Canada.
J Thorac Cardiovasc Surg. 2014 Jun;147(6):1946-55, 1955.e1. doi: 10.1016/j.jtcvs.2013.09.060. Epub 2013 Nov 13.
Excessive production of reactive oxygen species (ROS), in part via upregulation of DNA damage pathways, is a central mechanism governing pathologic activation of vascular smooth muscle cells (VSMCs). We hypothesized that the breast cancer 1, early onset (BRCA1) gene that is involved in cellular resistance to DNA damage limits ROS production and oxidative stress in VSMCs.
We evaluated basal and H2O2-stimulated expression of BRCA1 in human aortic smooth muscle cells (HASMCs). In vitro gain-of-function experiments were performed in BRCA1 adenovirus (Ad-BRCA1)-transfected HASMCs. ROS production and expression of Nox1 and its key regulatory subunit p47phox, key components of the ROS-generating nicotinamide adenine dinucleotide phosphate (NADPH) oxidase system, were evaluated. In vivo gain-of-function experiments were performed in spontaneously hypertensive (SHR) rats treated with Ad-BRCA1 (5 × 10(10) IU/rat). Blood pressure, vascular ROS generation, Nox1, and p47phox expression were measured.
BRCA1 was constitutively expressed in murine, rat, and human smooth muscle cells (SMCs). H2O2 significantly reduced BRCA1 expression with a resultant increase in ROS generation. BRCA1-overexpressing HASMCs were protected against H2O2-induced ROS generation, in part, via downregulation of the ROS-producing NADPH oxidase subunits Nox1 and p47phox. Ad-BRCA1 treatment in SHR rats was associated with a sustained increase in aortic BRCA1 expression, lower aortic ROS production, reduced γH2A.X levels, greater RAD51 foci, and decreases in blood pressure.
BRCA1 is a novel and previously unrecognized target that may shield VSMCs from oxidative stress by inhibiting NADPH Nox1-dependent ROS production. Gene- and/or cell-based approaches that improve BRCA1 bioavailability may represent a new approach in the treatment of diverse vascular diseases associated with an aberrant VSMC phenotype.
活性氧（ROS）的过度产生，部分通过 DNA 损伤途径的上调，是控制血管平滑肌细胞（VSMC）病理性激活的核心机制。我们假设参与细胞对 DNA 损伤的抵抗的乳腺癌 1 早发（BRCA1）基因限制了 VSMC 中 ROS 的产生和氧化应激。
我们评估了人主动脉平滑肌细胞（HASMC）中 BRCA1 的基础表达和 H2O2 刺激表达。在 BRCA1 腺病毒（Ad-BRCA1）转染的 HASMC 中进行了体外功能获得实验。评估了 ROS 的产生以及 NADPH 氧化酶系统的关键调节亚基 Nox1 和 p47phox 的表达，NADPH 氧化酶系统是产生 ROS 的关键组成部分。在接受 Ad-BRCA1（5×10（10）IU/大鼠）治疗的自发性高血压（SHR）大鼠中进行了体内功能获得实验。测量了血压、血管 ROS 生成、Nox1 和 p47phox 的表达。
BRCA1 在鼠、大鼠和人平滑肌细胞（SMCs）中持续表达。H2O2 显著降低 BRCA1 的表达，导致 ROS 产生增加。BRCA1 过表达的 HASMC 对 H2O2 诱导的 ROS 生成具有保护作用，部分原因是下调了产生 ROS 的 NADPH 氧化酶亚基 Nox1 和 p47phox。Ad-BRCA1 治疗 SHR 大鼠与主动脉 BRCA1 表达的持续增加、主动脉 ROS 产生减少、γH2A.X 水平降低、RAD51 焦点增加以及血压降低有关。
BRCA1 是一种新的、以前未被识别的靶点，它可以通过抑制 NADPH Nox1 依赖性 ROS 产生来保护 VSMC 免受氧化应激。提高 BRCA1 生物利用度的基因和/或细胞方法可能是治疗与异常 VSMC 表型相关的多种血管疾病的新方法。
