Defining a role of NADPH oxidase in myogenic tone development

IF 1.9 4区医学 Q3 HEMATOLOGY

Microcirculation Pub Date : 2022-03-14 DOI:10.1111/micc.12756

Galina Yu. Mironova, Neil Mazumdar, Ahmed M. Hashad, Mohammed A. El-Lakany, Donald G. Welsh

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引用次数: 4

Abstract

Objective

The myogenic response sets the foundation for blood flow control. Recent findings suggest a role for G protein-coupled receptors (GPCR) and signaling pathways tied to the generation of reactive oxygen species (ROS). In this regard, this study ascertained the impact of NADPH oxidase (Nox) on myogenic tone in rat cerebral resistance arteries.

Methods

The study employed real-time qPCR (RT-qPCR), pressure myography, and immunohistochemistry.

Results

G_q blockade abolished myogenic tone in rat cerebral arteries, linking GPCR to mechanosensation. Subsequent work revealed that general (TEMPOL) and mitochondrial specific (MitoTEMPO) ROS scavengers had little impact on myogenic tone, whereas apocynin, a broad spectrum Nox inhibitor, initiated transient dilation. RT-qPCR revealed Nox1 and Nox2 mRNA expression in smooth muscle cells. Pressure myography defined Nox1 rather than Nox2 is facilitating myogenic tone. We rationalized that Nox1-generated ROS was initiating this response by impairing the ability of the Ca_V3.2 channel to elicit negative feedback via BK_Ca. This hypothesis was confirmed in functional experiments. The proximity ligation assay further revealed that Nox1 and Ca_V3.2 colocalize within 40 nm of one another.

Conclusions

Our data highlight that vascular pressurization augments Nox1 activity and ensuing ROS production facilitates myogenic tone by limiting Ca²⁺ influx via Ca_V3.2.

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确定NADPH氧化酶在肌原性张力发育中的作用

目的肌原性反应为血流控制奠定基础。最近的研究结果表明，G蛋白偶联受体(GPCR)和信号通路与活性氧(ROS)的产生有关。因此，本研究确定了NADPH氧化酶(Nox)对大鼠脑阻力动脉肌张力的影响。方法采用实时荧光定量pcr (RT-qPCR)、压力肌图和免疫组化技术。结果Gq阻断可消除大鼠脑动脉肌原性张力，将GPCR与机械感觉联系起来。随后的研究表明，一般(TEMPOL)和线粒体特异性(MitoTEMPO) ROS清除剂对肌原性张力几乎没有影响，而罗布麻素(一种广谱Nox抑制剂)则会引发短暂的扩张。RT-qPCR检测平滑肌细胞中Nox1和Nox2 mRNA的表达。压力肌图定义Nox1而不是Nox2促进肌原性张力。我们推断nox1产生的ROS是通过削弱CaV3.2通道通过BKCa引发负反馈的能力来启动这种反应的。这一假设在功能实验中得到了证实。近端结扎实验进一步发现，Nox1和CaV3.2在40 nm范围内共定位。我们的数据强调血管加压增强了Nox1活性，随后ROS的产生通过限制Ca2+通过CaV3.2流入促进了肌张力。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Microcirculation 医学-外周血管病

CiteScore

5.00

自引率

4.20%

发文量

审稿时长

6-12 weeks

期刊介绍： The journal features original contributions that are the result of investigations contributing significant new information relating to the vascular and lymphatic microcirculation addressed at the intact animal, organ, cellular, or molecular level. Papers describe applications of the methods of physiology, biophysics, bioengineering, genetics, cell biology, biochemistry, and molecular biology to problems in microcirculation. Microcirculation also publishes state-of-the-art reviews that address frontier areas or new advances in technology in the fields of microcirculatory disease and function. Specific areas of interest include: Angiogenesis, growth and remodeling; Transport and exchange of gasses and solutes; Rheology and biorheology; Endothelial cell biology and metabolism; Interactions between endothelium, smooth muscle, parenchymal cells, leukocytes and platelets; Regulation of vasomotor tone; and Microvascular structures, imaging and morphometry. Papers also describe innovations in experimental techniques and instrumentation for studying all aspects of microcirculatory structure and function.