パート1：BioFlux板のマイクロ流体チャネルの準備。 <ol><li>フローセルの実験を実行する前に、人は目的のタンパク質のコーティングとマイクロ流体チャネルを準備する必要があります。このケースでは、コラーゲンは私が使用されます。各チャネルは、よく入口と出口を持っています。このプレートの場合、入口は井戸チャネルと同様の右にあるコンセントに給電左です。 </li><li> 0.02M酢酸に200μg/mlの濃度にコラーゲンI（5mg/ml株式）コーティングを希釈する。一つは、使用される各チャネルの20μlのが必要になります。マイクロピペットチップで穏やかtriterationで混ぜる。 </li><li>使用するそれぞれのチャネルにコーティングの20μlを添加する。一つは、よくマイクロピペットを用いて関心のマイクロ流体チャネルを供給するコンセントの内側のパンチに、液体を分注する必要があります。気泡を導入しないように、ピペットから空気を押さないでください。ないコラーゲンのコントロール（接着および凝集のためのネガティブコントロール）のためのコラーゲンせずに1つのチャネルが含まれています。 </li><li>一度、それらがすべて設定されている、4本のネジを締めて、最初の指でプレートにインターフェイスを接続、完全に締め、トルクドライバーを使用してください。それが最大の気密性に達するとトルクドライバがクリックされます。 </li><li> BioFluxソフトウェアで手動モードを使用して、コンセントも2dyn/cm -から2で興味のあるチャンネルに灌流を適用する。ここで一つは液体で満たされている反対側の内側のパンチを監視しなければなりません。これには数分かかります。一つは、これは顕微鏡で低消費電力の目標を使用して（4X）と同様またはプレートを保持し、下から入口の井戸を調べることでその入口を見つけることが発生見ることができます。一つは、最初ゆっくりと内側のパンチを満たす液体の小さなビーズが表示されるはずです。インレット内部のパンチがいっぱいになると、ソフトウェアでストップを押して、一度に灌流を停止します。 </li><li> 1時間室温でインキュベートする。 </li><li>インタフェースを削除し、よく口に1mlのPBSを（プラスのCa 2 + / Mg 2 +を ）追加する。 2dyn/cm 2でよく口から血流を開始します。 10分間の灌流を続ける。血流を停止し、インタフェースを削除します。 </li><li>入口と出口の井戸の両方から過剰なPBSを削除する - インナーパンチをいっぱいに液体を削除することはありません。ブロッキング溶液（PBS中の0.5％（v / v）のBSAを（プラスのCa 2 + / Mg 2 +を ））を使用してチャネルをブロックします。使用するだけでなく、各コンセントにブロッキング溶液1 mlを添加し、2dyn/cm 2でよくコンセントから灌流。 10分間の灌流を続ける。血流を停止し、インタフェースを削除します。このステップまでの準備のチャンネルは一日を通して使うことができます。 </li><li>血液を追加する前に、内側のパンチ以外のチャネルの両側で液体を取り除く。 </li></ol>パート2。 GPIIb / IIIaの阻害抗体を持つ血液を準備する。 <ol><li>コラーゲンは、チャネルでインキュベートされていますが、一つは全血を準備する必要があります。一つは、人間の血液を処理するときに、彼/彼女の機関によって決定バイオセーフティ規制に従ってください。 </li><li>クエン酸ナトリウムの抗凝固剤に引き込ま新鮮なヒト血液を（絶食した患者から）コレクションの3時間以内にご使用ください。 </li><li>回答4μMカルセインを追加することにより、血液を準備します。 DMSO中のカルセインAMの4mmの株式を準備し、A / V 1 / 1000の希釈で血液に追加対穏やかに転倒混和します。 </li><li> 1.5mlのマイクロチューブ - カルセインの1mlを10に血液をラベル付け午前注します。希望の希釈（IgGの分子量は〜150kDaである）でそれぞれにGPIIb / IIIa阻害薬の抗体を追加。例の希釈系列は、1200nMから9nMすることであり、抗体のコントロールはと無関係な抗体のコントロールが含まれていません。 抑制のための優秀なポジティブコントロールが20ug/mlの濃度でレオプロ（アブシキシマブ、イーライリリー）となる。穏やかに転倒混和します。 </li><li> 1時間室温でインキュベートする。静かに転倒混和して10分おきに混ぜる。 </li></ol>パート3：BF1000ワークステーション上でフローセルの実験を実行する。 <ol><li>最初に、人はBioFluxの制御モジュールで自動化されたプロトコルを設定する必要があります。コラーゲンの場合私は、人はよく口から10分間10dyn/cm 2を実行するプロトコルを設定する必要があります。この時点で、一つでもBF1000ワークステーションを使用してデータ収集パラメータを設定する必要があります、チャネルの位置を含めて、FITC波長と時間経過の情報にキャプチャ。それは合計10分の期間にわたって、チャネルあたり10倍の目標を30秒ごとに使用してビューの3つのフィールドをキャプチャすることをお勧めします。 </li><li>素早く作業を、別々の準備のチャンネルに各条件の準備血の500ulを置きます。コラーゲンとだけブロックされているものでコーティングされているチャンネルには抗体のコントロールの血を置かない。 </li><li>プレート上のインターフェイスを置きます。 </li><li> BF1000ワークステーションの顕微鏡でプレートを置きます。インターフェイス上でクランプ。 </li><li>プレートの負荷調整を行います。また、よく血液を含むものにステージを移動する。 FTを設定するICの画像キャプチャのパラメータ（露光時間、ゲイン等...）。 </li><li> BioFluxモンタージュのソフトウェアでは、同時に流れと取得を開始するために取得を開始します。 </li><li> BF1000ワークステーションからプレートを外し、制度的なガイドラインに従ってプレートを処分。 </li></ol>パート4：代表的な結果。 ここではマイクロ流体チャネルにおける血小板粘着と凝集のためのプロトコルが発表された。血小板凝集阻害剤による治療は、anti-GPIIb/IIIaもプロトコルに含まれていた。 BioFluxシステムのコラーゲンコーティングされたマイクロ流体チャネルを使用して、1つは、未処理の対照の血液サンプルとコーティングされていないチャネル上なく血栓形成に時間をかけて積極的な血栓形成を期待してください。 one最近行った実験では、制御条件下で凝集体の平均サイズは2000μm2であった。 図1。 <img src="/files/ftp_upload/1644/1644fig1.jpg" alt="図1" />活性化GPIIb / IIIaとは、血小板-血小板相互作用および凝集安定化1の強力なメディエーターである。コラーゲンへの接着は、この応答2を引き出すためにGPIIb / IIIaとの複合体を活性化する。せん断暴露前に1時間anti-GPIIb/IIIaとのインキュベーション後、1つは血栓の大きさの減少だけでなく、血栓形成の頻度の減少を観察することが予想されます。用量依存性の応答は、通常10dyn/cm 2で観察することができます。 図2。 <img src="/files/ftp_upload/1644/1644fig2.jpg" alt="図2" /> この特定の阻害剤のIC 50値は10 DYN / cm 2で17nMであった。抗体の制御なしに比べて最大阻害は、（このドナーのための）10 DYN / cm 2で11％であった。 ここでメソッドが特定の細胞外マトリックスタンパク質と血小板凝集の特異的阻害剤を用いて提示された一方で、プロトコルは他のコーティング、他の細胞型と細胞接着アッセイのための他の阻害剤への拡張が可能です。このような実験の成功するための秘訣は、すべての試薬のためのマイクロ流体チャネル、正しい希釈剤内のすべての試薬の適切な希釈、および適切な培養条件における気泡の回避です。

<ol>
	<li>Jackson, S. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+growing+complexity+of+platelet+aggregation.">The growing complexity of platelet aggregation.</a> Blood. 109, 5087-5095 (2007).</li><li>Nakamura, T., Kambayashi, J., Okuma, M., Tandon, N. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Activation+of+the+GP+IIb-IIIa+complex+induced+by+platelet+adhesion+to+collagen+is+mediated+by+both+alpha2beta1+integrin+and+GP.">Activation of the GP IIb-IIIa complex induced by platelet adhesion to collagen is mediated by both alpha2beta1 integrin and GP.</a> VI. J Biol Chem. 274, 11897-11903 (1999).</li></ol>

寄稿者は、流出Biosciences社の従業員です。

ここでメソッドが特定の細胞外マトリックスタンパク質と血小板凝集の特異的阻害剤を用いて提示された一方で、プロトコルは他のコーティング、他の細胞型と細胞接着アッセイのための他の阻害剤への拡張が可能です。このような実験の成功するための秘訣は、すべての試薬のためのマイクロ流体チャネル、正しい希釈剤内のすべての試薬の適切な希釈、および適切な培養条件における気泡の回避です。

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<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">	
		
		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>collagen I, Bovine</td>
<td>Reagent</td>
<td>Invitrogen</td>
<td>A1064401</td>
<td>other sources of collagen I can be used</td>
</tr>
<tr>
<td>PBS plus Ca/Mg</td>
<td>Reagent</td>
<td>Invitrogen</td>
<td>14040-117</td>
<td>&nbsp;</td>
<tr>
<td>Bovine serum albumin (BSA)</td>
<td>Reagent</td>
<td>EMD</td>
<td>EM-2930 Bottom of Form</td>
<td>From VWR</td>
</tr>
<tr>
<td>calcein AM</td>
<td>Reagent</td>
<td>Invitrogen</td>
<td>C1430</td>
<td>Calcein AM from BD can also be used</td>
</tr>
<tr>
<td>BioFlux 1000 System</td>
<td>Reagent</td>
<td>Fluxion Biosciences</td>
<td>Contact Company</td>
<td>&nbsp;</td>
<tr>
<td>BioFlux Plate</td>
<td>Reagent</td>
<td>Fluxion Biosciences</td>
<td>900013</td>
<td>&nbsp;</td>
<tr>
<td>antiGPIIb/IIIa</td>
<td>Reagent</td>
<td>Abcam</td>
<td>ab33407</td>
<td>an alternative # is ab15021</td>
</tr>
<tr>
<td>ReoPro</td>
<td>Reagent</td>
<td>Eli Lilly</td>
<td>&nbsp;</td>
<td>by Rx only</td>
</tr>		</tbody>
		</table>
		</div>

platelet adhesion and aggregation under flow using microfluidic flow cells

血小板凝集、内皮下細胞外マトリックスが露出された血管損傷への応答として発生します。血小板接着カスケードには、せん断流の存在下で、従来の（静的）ウェルプレートアッセイでは考慮されていない要因を行われます。この記事の生理的せん断流れの条件をエミュレートするマイクロ流体ウェルプレートフォーマットを利用した血小板凝集アッセイに関するレポート。細胞外タンパク質、コラーゲンI、またはvon Willebrand因子は、空気ポンプでアクティブな灌流を用いたマイクロ流体チャネル内に堆積される。マトリックスタンパク質を緩衝液で洗浄し、血小板の相互作用のためのマイクロ流体チャネルを準備するためにブロックされます。蛍光色素で標識された全血は、血小板活性化および凝集を達成するために様々な流量でチャネルを介して灌流される。血小板凝集の阻害はIC50用量応答データを生成するためのフローセル実験に先立って追加することができます。

Watch this Scientific Journal Video about Platelet Adhesion and Aggregation Under Flow using Microfluidic Flow Cells at JoVE.com

Platelet Adhesion and Aggregation Under Flow using Microfluidic Flow Cells

血小板接着カスケードには、せん断流の存在下で、従来の（静的）ウェルプレートアッセイでは考慮されていない要因を行われます。この記事の生理的せん断流れの条件をエミュレートするマイクロ流体ウェルプレートフォーマットを利用した血小板凝集アッセイに関するレポート。

マイクロ流体フローセルを使用して流れの下で血小板粘着と凝集

Platelet aggregation occurs in response to vascular injury where the extracellular matrix below the endothelium has been exposed. The platelet adhesion ...

platelet-adhesion-aggregation-under-flow-using-microfluidic-flow

Research

JoVE Journal

Biology

18.1K ビュー.  Fluxion Biosciences, Inc.. 血小板接着カスケードには、せん断流の存在下で、従来の（静的）ウェルプレートアッセイでは考慮されていない要因を行われます。この記事の生理的せん断流れの条件をエミュレートするマイクロ流体ウェルプレートフォーマットを利用した血小板凝集アッセイに関するレポート。

ビデオ: Platelet Adhesion and Aggregation Under Flow using Microfluidic Flow Cells

Flow Cytometry Purification of Mouse Meiotic Cells

The heterogeneous nature of cell types in the testis and the absence of meiotic cell culture models have been significant hurdles to the study of the unique differentiation programs that are manifest during meiosis. Two principal methods have been developed to purify, to varying degrees, various meiotic fractions from both adult and immature animals: elutriation or Staput (sedimentation) using BSA and/or percoll gradients. Both of these methods rely on cell size and density to separate meiotic cells1-5. Overall, except for few cell populations6, these protocols fail to yield sufficient purity of the numerous meiotic cell populations that are necessary for detailed molecular analyses. Moreover, with such methods usually one type of meiotic cells can be purified at a given time, which adds an extra level of complexity regarding the reproducibility and homogeneity when comparing meiotic cell samples.
Here, we describe a refined method that allows one to easily visualize, identify, and purify meiotic cells, from germ cells to round spermatids, using FACS combined with Hoechst 33342 staining7,8. This method provides an overall snapshot of the entire meiotic process and allows one to highly purify viable cells from most stage of meiosis. These purified cells can then be analyzed in detail for molecular changes that accompany progression through meiosis, for example changes in gene expression9,10and the dynamics of nucleosome occupancy at hotspots of meiotic recombination11.

An efficient method to obtain highly purified viable meiotic fractions from mouse testis is described, which combines a refined cell dissociation protocol with fluorescent activated cell sorting (FACS). This method takes advantage of differences in the DNA content and nuclear density of discrete meiotic fractions.

マウス減数分裂細胞のフローサイトメトリーの精製

The heterogeneous nature of cell types in the testis and the absence of meiotic cell culture models have been significant hurdles to the study of the ...

生物学

Optimized Staining and Proliferation Modeling Methods for Cell Division Monitoring using Cell Tracking Dyes

Fluorescent cell tracking dyes, in combination with flow and image cytometry, are powerful tools with which to study the interactions and fates of different cell types in vitro and in vivo.1-5 Although there are literally thousands of publications using such dyes, some of the most commonly encountered cell tracking applications include monitoring of:
<ol>
	<li>stem and progenitor cell quiescence, proliferation and/or differentiation6-8</li>
	<li>antigen-driven membrane transfer9 and/or precursor cell proliferation3,4,10-18 and</li>
	<li>immune regulatory and effector cell function1,18-21.</li>
</ol>
Commercially available cell tracking dyes vary widely in their chemistries and fluorescence properties but the great majority fall into one of two classes based on their mechanism of cell labeling. "Membrane dyes", typified by PKH26, are highly lipophilic dyes that partition stably but non-covalently into cell membranes1,2,11. "Protein dyes", typified by CFSE, are amino-reactive dyes that form stable covalent bonds with cell proteins4,16,18. Each class has its own advantages and limitations. The key to their successful use, particularly in multicolor studies where multiple dyes are used to track different cell types, is therefore to understand the critical issues enabling optimal use of each class2-4,16,18,24.
The protocols included here highlight three common causes of poor or variable results when using cell-tracking dyes. These are:
<ol>
	<li>Failure to achieve bright, uniform, reproducible labeling. This is a necessary starting point for any cell tracking study but requires attention to different variables when using membrane dyes than when using protein dyes or equilibrium binding reagents such as antibodies.</li>
	<li>Suboptimal fluorochrome combinations and/or failure to include critical compensation controls. Tracking dye fluorescence is typically 102 - 103 times brighter than antibody fluorescence. It is therefore essential to verify that the presence of tracking dye does not compromise the ability to detect other probes being used.</li>
	<li>Failure to obtain a good fit with peak modeling software. Such software allows quantitative comparison of proliferative responses across different populations or stimuli based on precursor frequency or other metrics. Obtaining a good fit, however, requires exclusion of dead/dying cells that can distort dye dilution profiles and matching of the assumptions underlying the model with characteristics of the observed dye dilution profile.</li>
</ol>
Examples given here illustrate how these variables can affect results when using membrane and/or protein dyes to monitor cell proliferation.

Successful use of cell tracking dyes to monitor immune cell function and proliferation involves several critical steps. We describe methods for: 1) obtaining bright, uniform, reproducible label-ing with membrane dyes; 2) selecting fluorochromes and data acquisition conditions; and 3) choosing a model to quantify cell proliferation based on dye dilution.

細胞トラッキング染料を使用して細胞分裂監視のための最適化された染色と増殖モデリング方法

Fluorescent cell tracking dyes, in combination with flow and image cytometry, are powerful tools with which to study the interactions and fates of ...

4D Imaging of Protein Aggregation in Live Cells

One of the key tasks of any living cell is maintaining the proper folding of newly synthesized proteins in the face of ever-changing environmental conditions and an intracellular environment that is tightly packed, sticky, and hazardous to protein stability1. The ability to dynamically balance protein production, folding and degradation demands highly-specialized quality control machinery, whose absolute necessity is observed best when it malfunctions. Diseases such as ALS, Alzheimer's, Parkinson's, and certain forms of Cystic Fibrosis have a direct link to protein folding quality control components2, and therefore future therapeutic development requires a basic understanding of underlying processes. Our experimental challenge is to understand how cells integrate damage signals and mount responses that are tailored to diverse circumstances.
The primary reason why protein misfolding represents an existential threat to the cell is the propensity of incorrectly folded proteins to aggregate, thus causing a global perturbation of the crowded and delicate intracellular folding environment1. The folding health, or "proteostasis," of the cellular proteome is maintained, even under the duress of aging, stress and oxidative damage, by the coordinated action of different mechanistic units in an elaborate quality control system3,4. A specialized machinery of molecular chaperones can bind non-native polypeptides and promote their folding into the native state1, target them for degradation by the ubiquitin-proteasome system5, or direct them to protective aggregation inclusions6-9.
In eukaryotes, the cytosolic aggregation quality control load is partitioned between two compartments8-10: the juxtanuclear quality control compartment (JUNQ) and the insoluble protein deposit (IPOD) (Figure 1 - model). Proteins that are ubiquitinated by the protein folding quality control machinery are delivered to the JUNQ, where they are processed for degradation by the proteasome. Misfolded proteins that are not ubiquitinated are diverted to the IPOD, where they are actively aggregated in a protective compartment.
Up until this point, the methodological paradigm of live-cell fluorescence microscopy has largely been to label proteins and track their locations in the cell at specific time-points and usually in two dimensions. As new technologies have begun to grant experimenters unprecedented access to the submicron scale in living cells, the dynamic architecture of the cytosol has come into view as a challenging new frontier for experimental characterization. We present a method for rapidly monitoring the 3D spatial distributions of multiple fluorescently labeled proteins in the yeast cytosol over time. 3D timelapse (4D imaging) is not merely a technical challenge; rather, it also facilitates a dramatic shift in the conceptual framework used to analyze cellular structure.
We utilize a cytosolic folding sensor protein in live yeast to visualize distinct fates for misfolded proteins in cellular aggregation quality control, using rapid 4D fluorescent imaging. The temperature sensitive mutant of the Ubc9 protein10-12 (Ubc9ts) is extremely effective both as a sensor of cellular proteostasis, and a physiological model for tracking aggregation quality control. As with most ts proteins, Ubc9ts is fully folded and functional at permissive temperatures due to active cellular chaperones. Above 30 &deg;C, or when the cell faces misfolding stress, Ubc9ts misfolds and follows the fate of a native globular protein that has been misfolded due to mutation, heat denaturation, or oxidative damage. By fusing it to GFP or other fluorophores, it can be tracked in 3D as it forms Stress Foci, or is directed to JUNQ or IPOD.

Cellular viability depends on timely and efficient management of protein misfolding. Here we describe a method for visualizing the different potential fates of a misfolded protein: refolding, degradation, or sequestration in inclusions. We demonstrate the use of a folding sensor, Ubc9ts, for monitoring proteostasis and aggregation quality control in live cells using 4D microscopy.

生細胞中のタンパク質凝集の4Dイメージング

One of the key tasks of any living cell is maintaining the proper folding of newly synthesized proteins in the face of ever-changing environmental ...

Measuring Intracellular Ca2+ Changes in Human Sperm using Four Techniques: Conventional Fluorometry, Stopped Flow Fluorometry, Flow Cytometry and Single Cell Imaging

Spermatozoa are male reproductive cells especially designed to reach, recognize and fuse with the egg. To perform these tasks, sperm cells must be prepared to face a constantly changing environment and to overcome several physical barriers. Being in essence transcriptionally and translationally silent, these motile cells rely profoundly on diverse signaling mechanisms to orient themselves and swim in a directed fashion, and to contend with challenging environmental conditions during their journey to find the egg. In particular, Ca2+-mediated signaling is pivotal for several sperm functions: activation of motility, capacitation (a complex process that prepares sperm for the acrosome reaction) and the acrosome reaction (an exocytotic event that allows sperm-egg fusion). The use of fluorescent dyes to track intracellular fluctuations of this ion is of remarkable importance due to their ease of application, sensitivity, and versatility of detection. Using one single dye-loading protocol we utilize four different fluorometric techniques to monitor sperm Ca2+ dynamics. Each technique provides distinct information that enables spatial and/or temporal resolution, generating data both at single cell and cell population levels.

Measuring Intracellular Ca2+ Changes in Human Sperm using Four Techniques: Conventional Fluorometry, Stopped Flow Fluorometry, Flow Cytometry and Single Cell Imaging

Intracellular Ca2+ dynamics are very important in sperm physiology and Ca2+-sensitive fluorescent dyes constitute a versatile tool to study them. Population experiments (fluorometry and stopped flow fluorometry) and single cell experiments (flow cytometry and single cell imaging) are used to track spatio-temporal [Ca2+] changes in human sperm cells.

細胞内Ca測定<sup&gt; 2 +</sup4つの方法を使用して人間の精子で&gt;変更：従来の蛍光測定、停止フロー蛍光法、フローサイトメトリーおよび単一細胞イメージング

Spermatozoa  are male reproductive cells especially designed to reach, recognize and fuse  with the egg. To perform these tasks, sperm cells must be ...

Reduced-gravity Environment Hardware Demonstrations of a Prototype Miniaturized Flow Cytometer and Companion Microfluidic Mixing Technology

Until recently, astronaut blood samples were collected in-flight, transported to earth on the Space Shuttle, and analyzed in terrestrial laboratories. If humans are to travel beyond low Earth orbit, a transition towards space-ready, point-of-care (POC) testing is required. Such testing needs to be comprehensive, easy to perform in a reduced-gravity environment, and unaffected by the stresses of launch and spaceflight. Countless POC devices have been developed to mimic laboratory scale counterparts, but most have narrow applications and few have demonstrable use in an in-flight, reduced-gravity environment. In fact, demonstrations of biomedical diagnostics in reduced gravity are limited altogether, making component choice and certain logistical challenges difficult to approach when seeking to test new technology. To help fill the void, we are presenting a modular method for the construction and operation of a prototype blood diagnostic device and its associated parabolic flight test rig that meet the standards for flight-testing onboard a parabolic flight, reduced-gravity aircraft. The method first focuses on rig assembly for in-flight, reduced-gravity testing of a flow cytometer and a companion microfluidic mixing chip. Components are adaptable to other designs and some custom components, such as a microvolume sample loader and the micromixer may be of particular interest. The method then shifts focus to flight preparation, by offering guidelines and suggestions to prepare for a successful flight test with regard to user training, development of a standard operating procedure (SOP), and other issues. Finally, in-flight experimental procedures specific to our demonstrations are described.

Spaceflight blood diagnostics need innovation. Few demonstrations have been published illustrating in-flight, reduced-gravity health diagnostic technology. Here we present a method for construction and operation of a parabolic flight test rig for a prototype point-of-care flow-cytometry design, with components and preparation strategies adaptable to other setups.

プロトタイプ小型化フローサイトメーターおよびコンパニオンマイクロ流体混合技術の縮小重力環境ハードウェアデモンストレーション

Until recently, astronaut blood samples were collected in-flight, transported to earth on the Space Shuttle, and analyzed in terrestrial laboratories. If ...

Cytosolic Calcium Measurements in Renal Epithelial Cells by Flow Cytometry

A variety of cellular processes, both physiological and pathophysiological, require or are governed by calcium, including exocytosis, mitochondrial function, cell death, cell metabolism and cell migration to name but a few. Cytosolic calcium is normally maintained at low nanomolar concentrations; rather it is found in high micromolar to millimolar concentrations in the endoplasmic reticulum, mitochondrial matrix and the extracellular compartment. Upon stimulation, a transient increase in cytosolic calcium serves to signal downstream events. Detecting changes in cytosolic calcium is normally performed using a live cell imaging set up with calcium binding dyes that exhibit either an increase in fluorescence intensity or a shift in the emission wavelength upon calcium binding. However, a live cell imaging set up is not freely accessible to all researchers. Alternative detection methods have been optimized for immunological cells with flow cytometry and for non-immunological adherent cells with a fluorescence microplate reader. Here, we describe an optimized, simple method for detecting changes in epithelial cells with flow cytometry using a single wavelength calcium binding dye. Adherent renal proximal tubule epithelial cells, which are normally difficult to load with dyes, were loaded with a fluorescent cell permeable calcium binding dye in the presence of probenecid, brought into suspension and calcium signals were monitored before and after addition of thapsigargin, tunicamycin and ionomycin.

Calcium is involved in numerous physiological and pathophysiological signaling pathways. Live cell imaging requires specialized equipment and can be time consuming. A quick, simple method using a flow cytometer to determine relative changes in cytosolic calcium in adherent epithelial cells brought into suspension was optimized.

フローサイトメトリーによる腎上皮細胞における細胞質ゾルカルシウム測定

A variety of cellular processes, both physiological and pathophysiological, require or are governed by calcium, including exocytosis, mitochondrial ...

LED Thermo Flow &#8212; Combining Optogenetics with Flow Cytometry

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.

LED Thermo Flow &amp;#8212; Combining Optogenetics with Flow Cytometry

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.

LEDサーモフロー - フローサイトメトリーで光遺伝学を組み合わせます

Optogenetic tools allow isolated, functional investigations of almost any signaling molecule within complex signaling pathways. A major obstacle is the ...

Analysis of Cell Suspensions Isolated from Solid Tissues by Spectral Flow Cytometry

Flow cytometry has been used for the past 40 years to define and analyze the phenotype of lymphoid and other hematopoietic cells. Initially restricted to the analysis of a few fluorochromes, currently there are dozens of different fluorescent dyes, and up to 14-18 different dyes can be combined at a time. However, several limitations still impair the analytical capabilities. Because of the multiplicity of fluorescent probes, data analysis has become increasingly complex due to the need of large, multi-parametric compensation matrices. Moreover, mutant mouse models carrying fluorescent proteins to detect and trace specific cell types in different tissues have become available, so the analysis (by flow cytometry) of auto-fluorescent cell suspensions obtained from solid organs is required. Spectral flow cytometry, which distinguishes the shapes of emission spectra along a wide range of continuous wavelengths, addresses some of these problems. The data is analyzed with an algorithm that replaces compensation matrices and treats auto-fluorescence as an independent parameter. Thus, spectral flow cytometry should be capable of discriminating fluorochromes with similar emission peaks and can provide a multi-parametric analysis without compensation requirements.
This protocol describes the spectral flow cytometry analysis, allowing for a 21-parameter (19 fluorescent probes) characterization and the management of an auto-fluorescent signal, providing high resolution in minor population detection. The results presented here show that spectral flow cytometry presents advantages in the analysis of cell populations from tissues difficult to characterize in conventional flow cytometry, such as the heart and the intestine. Spectral flow cytometry thus demonstrates the multi-parametric analytical capacity of high-performing conventional flow cytometry without the requirement for compensation and enables auto-fluorescence management.

This article describes spectral cytometry, a new approach in flow cytometry that uses the shapes of emission spectra to distinguish fluorochromes. An algorithm replaces compensations and can treat auto-fluorescence as an independent parameter. This new approach allows for the proper analysis of cells isolated from solid organs.

スペクトラルフローサイトメトリーにより固形組織から単離された細胞懸濁液の分析

Flow cytometry has been used for the past 40 years to define and analyze the phenotype of lymphoid and other hematopoietic cells. Initially restricted to ...

Live-cell Imaging of Platelet Degranulation and Secretion Under Flow

Blood platelets are essential players in hemostasis, the formation of thrombi to seal vascular breaches. They are also involved in thrombosis, the formation of thrombi that occlude the vasculature and injure organs, with life-threatening consequences. This motivates scientific research on platelet function and the development of methods to track cell-biological processes as they occur under flow conditions.
A variety of flow models are available for the study of platelet adhesion and aggregation, two key phenomena in platelet biology. This work describes a method to study real-time platelet degranulation under flow during activation. The method makes use of a flow chamber coupled to a syringe-pump setup that is placed under a wide-field, inverted, LED-based fluorescence microscope. The setup described here allows for the simultaneous excitation of multiple fluorophores that are delivered by fluorescently labeled antibodies or fluorescent dyes. After live-cell imaging experiments, the cover glasses can be further processed and analyzed using static microscopy (i.e., confocal microscopy or scanning electron microscopy).

This work describes a fluorescence microscopy-based method for the study of platelet adhesion, spreading, and secretion under flow. This versatile platform enables the investigation of platelet function for mechanistic research on thrombosis and hemostasis.

流れの下での血小板の脱顆粒および分泌の生きた細胞イメージング

Blood platelets are essential players in hemostasis, the formation of thrombi to seal vascular breaches. They are also involved in thrombosis, the ...

Quantification of Cellular Densities and Antigenic Properties using Magnetic Levitation

The described method was developed based on the principles of magnetic levitation, which separates cells and particles based on their density and magnetic properties. Density is a cell type identifying property, directly related to its metabolic rate, differentiation, and activation status. Magnetic levitation allows a one-step approach to successfully separate, image and characterize circulating blood cells, and to detect anemia, sickle cell disease, and circulating tumor cells based on density and magnetic properties. This approach is also amenable to detecting soluble antigens present in a solution by using sets of low- and high-density beads coated with capture and detection antibodies, respectively. If the antigen is present in solution, it will bridge the two sets&#160;of beads, generating a new bead-bead complex, which will levitate in between the rows of antibody-coated beads. Increased concentration of the target antigen in solution will generate a larger number of bead-bead complexes when compared to lower concentrations of antigen, thus allowing for quantitative measurements of the target antigen. Magnetic levitation is advantageous to other methods due to its decreased sample preparation time and lack of dependance on classical readout methods. The image generated is easily captured and analyzed using a standard microscope or mobile device, such as a smartphone or a tablet.

This paper describes a magnetic levitation-based method that can specifically detect the presence of antigens, either soluble or membrane-bound, by quantifying changes in the levitation height of capture beads with fixed densities.

磁気浮上を用いた細胞密度と抗原特性の定量化

The described method was developed based on the principles of magnetic levitation, which separates cells and particles based on their density and magnetic ...