LED热流量 - 结合光遗传学与流式细胞仪
Summary
Optically controlled substances are powerful tools to study signaling pathways. To expand the spectrum of possible experiments, we developed a device for studying optically controlled substances in real time using flow cytometry: the LED Thermo Flow.
Abstract
Optogenetic tools allow isolated, functional investigations of almost any signaling molecule within complex signaling pathways. A major obstacle is the controlled delivery of light to the cell sample and hence the most popular tools for optogenetic studies are microscopy-based cell analyses and in vitro experiments. The flow cytometer has major advantages over a microscope, including the ability to rapidly measure thousands of cells at single cell resolution. However, it is not yet widely used in optogenetics. Here, we present a device that combines the power of optogenetics and flow cytometry: the LED Thermo Flow. This device illuminates cells at specific wavelengths, light intensities and temperatures during flow cytometric measurements. It can be built at low cost and be used with most common flow cytometers. To demonstrate its utility, we characterized the photoswitching kinetics of Dronpa proteins in vivo and in real time. This protocol can be adapted to almost all optically controlled substances and substantially expands the set of possible experiments. More importantly, it will greatly simplify the discovery and development of new optogenetic tools.
Introduction
光遗传学工具已日益普及，部分是因为它们可用于破译信号通路1-4的布线。它们是基于可光活化的蛋白质当与光照射改变其构象和结合亲和力的能力。融合这些蛋白质信令元素允许单个玩家的复杂细胞内信号通路5-12内的特定调节。因此，信号传导途径可以以高时空分辨率进行研究。
大多数基于细胞的光遗传学研究利用基于显微镜的方法，在光的存在下培养相结合，随后通过生物化学分析11,12。与此相反，一个流式细胞singularizes细胞沿着毛细管并测量细胞大小，粒度和荧光强度。这种方法具有在显微镜或生物化学方法主要优点，包括分析thousan的能力家里单细胞分辨率的细胞在非常短的时间的DS。因此，理想的是光遗传学流式细胞仪结合。
据我们所知，有一个光遗传学流式细胞仪没有既定的协议。一个被广泛接受的过程是从手电筒设备反应管外手动点亮照明单元。然而，在流动手册照明仪要求光通过反应管，并用于活细胞成像，圆柱形，加热的水室中。这会导致大量的光散射和光的损失。此外，通过手动照明提供的光强度不实验（角度，距离， 等等 ）之间的可再现的和有一个实际的限制，以波长的数量在一项实验。
通过构造该LED热流量设备，我们能够克服这些限制。与此设备中，细胞可以在一个临时的特定波长照射erature控制在流式细胞仪的测量方式。这使得在与实验之间的精确和可重复的光量。
为了证明我们的体内装置的效用，我们在光控记录在拉莫斯B细胞Dronpa的荧光信号。拉莫斯B细胞是从人Burkitt淋巴瘤的。 Dronpa是存在作为单体，二聚体或四聚体的荧光蛋白质。在它的单体形式，它是无荧光的。照明用400纳米的光诱导二聚和四聚并呈现Dronpa蛋白荧光。这个过程可以通过用500nm的光照射可以相反。该Dronpa蛋白已被用于控制信号蛋白4,13的功能和位置。
在此，我们表示拉莫斯B细胞Dronpa连接子Dronpa蛋白研究Dronpa光控的在流式细胞仪。使用我们的装置中，我们能够有效地和重复性光控Dronpa同时记录实时荧光强度。这种方法比用人工照明照度当前的协议提供了巨大的优势和显著扩大了光遗传学工具和笼化合物的实验剧目。使用我们的设备将显著简化并加速的新颖光遗传学工具的发现和开发。
Protocol
Representative Results
Discussion
LED的热流量是一个创新的设备，研究光遗传学工具在流式细胞仪。
到目前为止，光遗传学样品已经只能用显微镜激光或闪光装置11,12照明。根据不同的手电筒与样品的角度和距离，在光照的量实质性变性实验之间的预期。此外，存在于手电筒一个人可以在实验操作的数目的限制。这限制了实验剧目和重现性。这些限制我们的装置，该装置可用于在活细胞中表征实时光…
Divulgations
The authors have nothing to disclose.
Acknowledgements
We thank J. Schmidt from the University of Freiburg for constructing the device. We thank P. Nielsen and D. Medgyesi for their support and critical reading of this manuscript. This study was supported by the Deutsche Forschungsgemeinschaft through SFB746 and by the Excellence Initiative of the German Research Foundation (GSC-4, Spemann Graduate School).
Materials
| Glass FACS tube | Thermo Fisher Scientific; Waltham, USA | 14-961-26 | Borosilicate glass tubes 12×75 mm |
| Flow Cytometer | BD Bioscienceg; Heidelberg, Germany | Fortessa II | Special Order |
| Dronpa: pcDNA3-mNeptune2-N | Addgene; Cambridge, USA | 41645 | |
| PolyJet | SignaGen, Rockville, USA | SL100688 | |
| LED 505 nm | Avago Technologies; Boeblingen, Germany | HLMP-CE34-Y1CDD | |
| LED 400 nm | Avago Technologies; Boeblingen, Germany | UV5TZ-400-15 | |
| Plexiglas tube 15 mm | Maertin; Freiburg, Germany | 76999 | |
| Plexiglas 3 mm | Maertin; Freiburg, Germany | 692230 | |
| Plexiglas 2,5 mm | Maertin; Freiburg, Germany | 692225 | |
| Plexiglas 1,5 mm | Maertin; Freiburg, Germany | 692215 | |
| PVC tile 5 mm | Maertin; Freiburg, Germany | 690020.005 | |
| PVC tile 6 mm | Maertin; Freiburg, Germany | 690020.006 | |
| PVC block 50 mm | Maertin; Freiburg, Germany | 690020.050 | |
| RPMI | Invitrogen, Life Technologies; Darmstadt, Germany | 61870-010 | |
| 2-Mercaptoethanol | EMD; Germany | 805740 | |
| FCS | PAN Biotech; Aidenbach, Germany | P30-3302 | |
| Penicillin/Strptomycin (10000 U/ml) | Invitrogen, Life Technologies; Darmstadt, Germany | 15140-122 | |
| Acrifix plexiglas glue | Evonic industries, Essen, Germany | 1R0192 | |
| Tangit PVC-U glue | Henkel, Düsseldorf, Germany |
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