Summary

使用HeLa细胞中的实时成像对线粒体膜电位和超氧化物水平进行基于荧光的定量

Published: May 12, 2023
doi:

Summary

该技术描述了一种有效的工作流程,使用基于荧光的实时成像可视化和定量测量HeLa细胞内的线粒体膜电位和超氧化物水平。

Abstract

线粒体是通过ATP合成 控制 能量产生,对代谢稳态至关重要的动态细胞器。为了支持细胞代谢,各种线粒体质量控制机制合作以维持健康的线粒体网络。其中一种途径是线粒体自噬,其中PTEN诱导的激酶1(PINK1)和受损线粒体的Parkin磷酸化泛素化促进自噬体隔离并随后通过溶酶体融合 细胞中去除。线粒体自噬对细胞稳态很重要,帕金的突变与帕金森病(PD)有关。由于这些发现,人们非常重视研究线粒体损伤和周转,以了解线粒体质量控制的分子机制和动力学。在这里,活细胞成像用于可视化HeLa细胞的线粒体网络,以量化线粒体解偶联剂羰基氰间氯苯基腙(CCCP)处理后的线粒体膜电位和超氧化物水平。此外,表达抑制帕金依赖性线粒体自噬的帕金PD连锁突变(ParkinT240R)以确定与表达野生型帕金的细胞相比突变如何影响线粒体网络。此处概述的方案描述了一种简单的工作流程,使用基于荧光的方法有效地量化线粒体膜电位和超氧化物水平。

Introduction

线粒体网络是一系列相互连接的细胞器,在能量产生1,先天免疫23和细胞信号传导45中起着至关重要的作用。线粒体失调与帕金森病(PD)等神经退行性疾病有关67。PD是一种进行性神经退行性疾病,影响黑质的多巴胺能神经元,影响全球近1000万人8。PD与线粒体自噬有遗传联系,线粒体自噬是维持细胞稳态所必需的线粒体质量控制途径,选择性地去除受损的线粒体910。研究已经确定了多种独立的线粒体自噬途径,包括含有 1 (FUNDC1) 介导的线粒体自噬的 FUN14 结构域、Bcl-2 相互作用蛋白 3 (BNIP3) 促进的线粒体自噬、NIX 依赖性线粒体自噬以及特征明确的 PTEN 诱导激酶 1 (PINK1)/帕金调节线粒体自噬1011。PINK1(一种假定的激酶)和帕金(一种E3泛素连接酶)与磷酸泛素受损线粒体协同工作,后者驱动自噬体的形成,吞噬受损细胞器并与溶酶体融合以启动降解1213,141516帕金的突变与PD相关的表型有关,例如通过多巴胺能神经元丢失引起的神经变性1718

在这里,描述了一个协议,其中HeLa细胞,常规使用的源自宫颈癌的永生化细胞,用于研究Parkin在维持线粒体网络健康中的作用。HeLa细胞表达的内源性帕金水平可以忽略不计,因此需要外源性帕金表达19。为了研究Parkin在线粒体网络健康中的作用,用野生型Parkin(ParkinWT),Parkin突变体(ParkinT240R)或空对照载体转染HeLa细胞。ParkinT240R是一种常染色体隐性幼年帕金森综合征突变,影响Parkin E3连接酶活性,显着降低线粒体自噬途径的效率20。HeLa细胞暴露于轻度(5μM)或严重(20μM)浓度的羰基氰间氯苯基腙(CCCP),一种线粒体解偶联剂。用高浓度的CCCP处理通常用于在各种细胞系中诱导帕金介导的线粒体自噬,例如HeLa和COS-7细胞212223

治疗后,该方案使用两种当前可用的线粒体靶向荧光染料对线粒体网络进行实时成像。四甲基罗丹明、乙酯、高氯酸盐 (TMRE) 是一种阳离子染料,其荧光基于线粒体膜电位24,而 MitoSOX 是一种线粒体超氧化物指示剂,其中荧光强度是超氧化物浓度25 的函数。最后,概述的方案使用基于荧光的定量和简单的工作流程来有效地量化线粒体膜电位和超氧化物水平,而用户偏差的范围最小。尽管该协议旨在研究HeLa细胞中的线粒体功能,但它可以适用于其他细胞系和原代细胞类型,以定量表征线粒体网络健康。

Protocol

1. 生物样品的制备 注意:在生物安全柜中使用无菌技术执行以下步骤。用70%乙醇喷洒机柜表面和所有材料。 HeLa细胞培养和转染在Dulbecco的改良鹰培养基(DMEM)中培养30,000个HeLa细胞,含有4.5g / L葡萄糖,补充有10%胎牛血清和1%L-谷氨酰胺溶液(HeLa培养基;参见 材料表)。将细胞铺在含有 2 mL 预热 HeLa 培养基的 35 mm 玻璃底成像皿(参见<str…

Representative Results

在该协议中,基于荧光的定量用于测量CCCP处理后线粒体网络的膜电位和超氧化物水平(图1)。该工作流程使用了HeLa细胞,这是一种源自宫颈癌的永生化细胞系。HeLa细胞通常用于研究线粒体生物学,并且相对平坦,因此很容易使用显微镜可视化线粒体网络。为了研究Parkin在维持线粒体网络健康中的作用,用空对照载体ParkinWT或ParkinT240R (一种破坏线粒体自噬…

Discussion

此处概述的工作流程可用于使用基于荧光的成像稳定且可重复地量化线粒体膜电位和超氧化物水平30。在设计这些实验时,需要考虑重要的技术限制。用空的YFP载体YFP-ParkinWT或YFP-ParkinT240R转染HeLa细胞。空的YFP载体被用作对照,以确认实验结果是帕金特有的。对于瞬时转染,通过实验确定DNA与转染试剂的质量比为1:3,以产生最高的转染率,其中每个构建体使用2 μ…

Disclosures

The authors have nothing to disclose.

Acknowledgements

我们感谢埃文斯实验室的成员对这份手稿的深思熟虑的反馈。这项工作得到了杜克怀特黑德学者,杜克科学和技术学者和霍华德休斯医学研究所(HHMI)汉娜格雷奖学金的支持。 图1A 是使用 BioRender.com 制作的。

Materials

Chemicals, Peptides, and Recombinant Proteins
CCCP (carbonyl cyanide m-chlorophenyl hydrazone)  Sigma-Aldrich C2759
DMEM (1x) with 4.5 g/L glucose Gibco 11-965-084
DMSO, Anhydrous ThermoFisher Scientific D12345
Fetal Bovine Serum Hyclone SH3007103
FuGENE 6 (Tranfection Reagent) Promega E2691
GlutaMAX 100x (L-Glutamine Solution)  Gibco  35-050-061
Hoescht 33342 ThermoFisher Scientific 62249
MitoSOX  Red  ThermoFisher Scientific M36008
MitoTracker Deep Red ThermoFisher Scientific M7514
Opti-MEM (Redued Serum media) ThermoFisher scientific 31985070
Tetramethylrhodamine, Ethyl Ester, Perchlorate (TMRE)  ThermoFisher Scientific T669
Experimental models: Organisms/Strains
HeLa-M (Homo sapiens) A. Peden (Cambridge Institute for Medical Research) N/A
Recombinant DNA
EYFP Empty Vector N/A N/A
YFP-Parkin T240R This Paper Generated by site-directed mutagenesis from YFP-Parkin
YFP-Parkin WT Addgene; PMID:19029340 RRID:Addgene_23955
Software and Algorithms
Adobe Illustrator Adobe Inc. https://www.adobe.com/products/illustrator (Schindelin, 2012)
Excel (Spreadsheet Software) Microsoft Office  https://www.microsoft.com/en-us/microsoft-365/excel
ImageJ https://imagej.net/software/fiji/
Leica Application Suite (LAS X) Leica https://www.leica-microsystems.com/products/microscope-software/p/leica-las-x-ls/
Microsoft Excel Microsoft Office https://www.microsoft.com/excel
Prism9 (Statistical Analysis Software) GraphPad Software https://www.graphpad.com
Other
35 mm Dish, No. 1.5 Coverslip, 20 mm Glass Diameter, Uncoated MatTek P35G-1.5-20-C
Cage Incubator (Environmental Chamber) Okolab https://www.oko-lab.com/cage-incubator
DMiL Inverted Microscope Leica N/A
LIGHTNING Deconvolution Software Leica N/A
STELLARIS 8 confocal microscope Leica N/A

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Cite This Article
Fazli, M., Evans, C. S. Fluorescence-Based Quantification of Mitochondrial Membrane Potential and Superoxide Levels Using Live Imaging in HeLa Cells. J. Vis. Exp. (195), e65304, doi:10.3791/65304 (2023).

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