Summary

在定义良好的剪切应力下单细胞电电流的电生理记录

Published: August 02, 2019
doi:

Summary

该协议的目的是描述一个经过修改的平行板流室,用于研究通过剪切应力实时激活美能敏感子孔通道。

Abstract

众所周知,流体剪切应力在内皮功能中起着重要作用。在大多数血管病床上,血流急剧增加引起的剪切应力升高会触发信号级联,导致血管扩张,从而减轻血管壁上的机械应力。众所周知,剪切应力模式也是动脉粥样硬化发展的关键因素,而层状剪切应力是具有英雄保护作用的,而受干扰的剪切应力是亲动脉粥样硬化的。虽然我们对各种中间细胞信号通路有详细的了解,但首先将机械刺激转化为化学中介的受体并不完全了解。干扰性电子通道对剪切的响应至关重要,并调节剪切诱导的细胞信号,从而控制血管活性介质的产生。这些通道是最早激活的剪切信号成分之一,通过促进一氧化氮生产(例如,向内矫正 K+ [Kir] 和瞬态受体电位 [TRP],与剪切引起的血管化相关通道)和内皮超极化因子(例如,基尔和钙激活K +[KCa]通道)和剪切引起的血管收缩,通过一个未确定的机制,涉及压电通道。了解这些通道被剪切力(即直接或通过初级机械受体)激活的生物物理机制,可以为解决与内皮功能障碍相关的病理生理学提供潜在的新靶点和英雄发生。利用电生理学实时记录流动引起的电通道活化仍然是一大挑战。将细胞暴露在定义良好的剪切应力下的标准方法,如锥体和板流变仪和闭合平行板流室,不允许实时研究电子通道激活。该协议的目的是描述一个经过修改的平行板流室,它允许在定义明确的剪切应力下实时电生理记录机械敏感电道。

Introduction

众所周知,血流产生的血动力在内皮和血管功能1、2中起着主要作用。众所周知,几种类型的子通道对剪切应力3、4、5的变化有剧烈反应,导致理论认为,子通道可以是初级剪切应力传感器。最近,我们和其他人表明,对剪切应力的血管敏感通道在若干剪切应力敏感血管功能中起着关键作用,包括对剪切应力6、7、8的血管活性反应,发育性血管生成9。然而,离音通道的剪切应力灵敏度机制几乎完全未知。这种知识差距可能是由于在明确定义的剪切应力下进行电生理记录的技术困难。因此,在本文中,我们提供了一个逐步的详细协议,在我们的实验室中例行执行,以实现这个目标6,7,10,11。

该方法的总体目标是允许在生理范围内明确定义的剪切应力下对电导道机活化进行实时调查。这是通过修改标准平行板流室来实现的,使电生理移液器能够降入腔室,并在实时接触流量时进入底部板上生长的细胞,从而提供了独特的方法来实现这一点进球6,7,11 。相比之下,在以前的出版物中描述的标准平行板流室可用于对暴露于剪切力12或其他非侵入性方法细胞进行实时成像分析,但不适用于电 生理。同样,锥体和板装置,另一种强大的方法,使细胞暴露在剪切应力15,16也不适合电生理记录。因此,这些流动装置不允许研究光通道的剪切应力敏感性。在流下进行电生理记录的困难是缺乏关于这些关键影响的机制的信息的主要原因。

就实现同一目标的替代方法而言,没有一种方法准确或控制。一些早期的研究试图通过将细胞暴露在来自另一个移液器的液体流中来记录流中的离子电池通道活动,这些液体从17、18号进入细胞附近。这是高度非生理的,因为在这些条件下产生的机械力与血管中剪切应激的生理特征几乎没有共同之处。类似的关注也适用于通过灌注开放腔来模拟生理剪切应力的尝试。正如我们早期研究10中详细讨论的,一个开放的液体-空气界面会产生多重干扰和再循环,这是非生理的。为了解决所有这些问题,我们设计了一个经过改进的平行板(MPP)流动室,在早先的研究中,我们也被称为”微创流量装置”,在6、7、10、11中,我们制造了从丙烯酸和广泛使用在我们的实验室。然而,尽管设计的原始描述已经发表近20年,并且是唯一允许在定义明确的剪切应力下进行电生理记录的流装置,但这种方法并没有其他实验室采用,只有极少数研究试图记录流下的电流。因此,我们相信,提供使用MPP流动室的详细描述,将非常有助于研究那些对美能敏感性水道和血管生物学感兴趣的人。

Protocol

伊利诺伊大学芝加哥动物护理委员会(#16-183)批准了动物在我们的研究中的使用。 1. 改进平行板流室的装配 注:有关 MPP 流室件件的 D,请参阅表 1和图1。请参阅图1,详细说明装配室件的方向。 要将矩形盖玻璃 D 粘附到 C 件的底部,首先通过将 500 μL 硅胶弹性体固化剂彻底混合成 5 mL …

Representative Results

图1显示了显微镜台上MPP流室的不同视图(上面板)和MPP流室(底部面板)的示意图表示。原理图详细说明了整个设备和流室的尺寸。图 2显示了我们实验室(上面板)MPP 流动室的重力灌注系统的照片。还显示了流系统(底部面板)的示意图,用于突出显示将流动室中的细胞与灌注系统输送溶液和溶液真空去除力分离的步骤。 <p class="jove_c…

Discussion

血管系统不断暴露于活跃的血液动力学力量,激活肌敏性电通道3,22,但这些通道在剪切应力引起的回激转导的生理作用只是开始出现4,6,8。负责剪切应力激活通道的机械敏感性的机制仍然未知。本文详述的协议描述了实时对层状剪切应力暴露的美感敏感子通道进行直接调查的方法。

Offenlegungen

The authors have nothing to disclose.

Acknowledgements

这项工作由国家心肺血液研究所(R01 HL073965,IL)和(T32 HL007829-24,ISF)资助。作者还感谢芝加哥伊利诺伊大学科学机器商店生成了我们最新的MPP流动室。

Materials

0.2 µm sterile syringe filters VWR 28145-501 Used for filtering electrophysiolgoical pipette solution
5 grade forceps Fine Scientific Tools 1252-30 Used for transferring digested arteries to fresh solution
9" Pasteur Pipet Fisher Scientifc 13-678-20D Used for mechanically disrupting digested arteries and transferring freshly isolated endohtelial cells 
12 mm diameter Cover glass circles Fisher Scientifc 12-545-80 For use with studies involving cultured cells and multiple treatments. Cells adhered to the cover glass are used for patch clamp analyses
24 x 40 mm Rectangluar Cover glass Sigma-Aldrich CLS2975224 Cover glass to be added to MPP flow chamber pieces C (Figure 1)
24 x 50 mm Rectangluar Cover glass Sigma-Aldrich CLS2975245 Cover glass to be added to MPP flow chamber E (Figure 1)
20 gauge syringe needles Becton Dickinson and Co 305175 For use in mechanical disruption of digested mesenteric arteries
35 mm Petri dish Genesee Scientific 32-103 For use in mechanical disruption of digested mesenteric arteries
Amphotericin B solubilized Sigma-Aldrich A9528-50MG Used for generating the perforated whole-cell patch configuration.
collagenase, type I Worthington Biochemical 100 mg – LS004194 Enzyme used in our laboratory as a brief digestion following the initial cocktail of neutral protease and elastase
Dimethyl Sulfoxide (DMSO) Fisher Scientifc 67-68-5 Solvent for Amphotericin B used in perforated whole-cell patch clamp
elastase, lyophilized Worthington Biochemical 25 mg – LS002290  Enzyme used in our laboratory in a cocktail with neutral protease/dispase to begin digestion of arteries for endothelial cell isolation.
Falcon Tissue culture Plate, 6-well, Flat Bottom with Low Evaporation Lid  Corning 353046 For use with studies involving cultured cells and multiple treatments
neutral protease/dispase Worthington Biochemical 10 mg- LS02100 50 mg – LS02104 Enzyme used in our laboratory in a cocktail with elastase to begin digestion of arteries for endothelial cell isolation
SylGard  World Precision Instruments SYLG184 Silicone elastomer for adhering the rectangular cover slip to the MPP flow chamber pieces C and E (Figure 1)
Tygon ND 10-80 tubing Microbore Tubing AAQ04133 ID: 0.05 in, OD: 0.09 in, inlet perfusion tubing for adminsitering flow to the chamber

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Fancher, I. S., Levitan, I. Electrophysiological Recordings of Single-cell Ion Currents Under Well-defined Shear Stress. J. Vis. Exp. (150), e59776, doi:10.3791/59776 (2019).

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