Neurogranin regulates eNOS function and endothelial activation
Neurogranin regulates eNOS function and endothelial activation
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DOI：
10.1016/j.redox.2020.101487
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发表时间：
2020-07-01
期刊：
影响因子：
11.4
通讯作者：
Nam, Hyung W.
中科院分区：
文献类型：
--
作者：
Cheriyan, Vino T.;Alfaidi, Mabruka;Nam, Hyung W.
内皮性一氧化氮（NO）是血管功能和血管重构的重要介质。NO是由内皮型一氧化氮合酶（eNOS）产生的，它通过钙（Ca2+）依赖性和Ca2+非依赖性途径被激活。在这里，我们报道了神经粒蛋白（Ng），它调节大脑中Ca2+-钙调蛋白（CaM）信号，在人和小鼠血管内皮细胞（EC）中唯一表达，也是eNOS调节所必需的。为了测试Ng在eNOS激活中的作用，我们在小鼠中使用Ng SiRNA和Ng敲除（Ng(-/-)）对人主动脉内皮细胞（HAEC）进行了Ng敲除。Ng表达缺失可降低小鼠HAEC中eNOS活性和NO生成。我们发现，短期层流和长时间振荡流剪切应力降低了Ng的表达，剪切应力降低了eNOS的表达以及eNOS在S1177位点的磷酸化。我们进一步发现，缺乏Ng表达会降低akt依赖性eNOS磷酸化、nf - κ b介导的eNOS表达，并促进内皮细胞活化。我们的研究结果还表明，Ng调节Ca2+依赖性钙调神经磷酸酶（CaN）活性，从而抑制Ca2+依赖性akt依赖性eNOS信号传导。此外，在血流介导的扩张实验中，小鼠中Ng的缺失也会降低eNOS活性并引起内皮功能障碍。我们的研究结果表明，Ng在Ca2+- cam依赖性eNOS调节中起着至关重要的作用，并有助于血管重塑，这对心血管疾病的病理生理非常重要。
Endothelial nitric oxide (NO) is a critical mediator of vascular function and vascular remodeling. NO is produced by endothelial nitric oxide synthase (eNOS), which is activated by calcium (Ca2+)-dependent and Ca2+-independent pathways. Here, we report that neurogranin (Ng), which regulates Ca2+-calmodulin (CaM) signaling in the brain, is uniquely expressed in endothelial cells (EC) of human and mouse vasculature, and is also required for eNOS regulation. To test the role of Ng in eNOS activation, Ng knockdown in human aortic endothelial cells (HAEC) was performed using Ng SiRNA along with Ng knockout (Ng(-/-)) in mice. Depletion of Ng expression decreased eNOS activity in HAEC and NO production in mice. We show that Ng expression was decreased by short-term laminar flow and long-them oscillating flow shear stress, and that Ng siRNA with shear stress decreased eNOS expression as well as eNOS phosphorylation at S1177. We further reveled that lack of Ng expression decreases both AKT-dependent eNOS phosphorylation, NF-kappa B-mediated eNOS expression, and promotes endothelial activation. Our findings also indicate that Ng modulates Ca2+-dependent calcineurin (CaN) activity, which suppresses Ca2+-independent AKT-dependent eNOS signaling. Moreover, deletion of Ng in mice also reduced eNOS activity and caused endothelial dysfunction in flow-mediated dilation experiments. Our results demonstrate that Ng plays a crucial role in Ca2+-CaM-dependent eNOS regulation and contributes to vascular remodeling, which is important for the pathophysiology of cardiovascular disease.