This work was supported by National Institutes of Health grants GM 100201 to I.F.S, and GM 048071 and GM 065830 to I.P.

私たちは、ヒト神経芽細胞腫SH-SY5Y細胞におけるローカルのCa 2+イベントを画像化するための詳細な手順を提示する。これらの手順は、多くの細胞型8-10画像内Ca 2+シグナルに適合させることができる。 細胞の調製<ol><li>培養細胞は、その供給者のウェブサイトに掲載されている指示に従って撮像される。 </li><li>画像化の前の数日間は、収穫細胞を1mlの0.25％トリプシン/ EDTA（2-3分）を用いて組織培養フラスコ中で増殖させた。剥離後、トリプシンを不活性化するために培養培地の等量を加える。 </li><li>皿あたり3-7×10 4細胞の密度でガラスボトムイメージング皿に血球計および種子細胞を用いて細胞カウントを行う。彼らは60％コンフルエンス（2-3日）に達するときイメージング実験のためのセルを選択します。 </li></ol>ソリューションおよび試薬の調製<ol><li>バッファリングされたCa 2+含有HEPESを準備（ミリモル）からなる塩溶液（Ca 2+の-HBSS）：135のNaCl、5.4のKCl、2のCaCl 2、1のMgCl 2、10 HEPES、および10グルコース。でpH = 7.4 NaOHで室温（RT）にて。 4℃でのグルコースや店舗の添加なしのCa 2+ -HBSSを準備します。使用直前に液にグルコースを追加します。 </li><li>蛍光のCa 2+指示薬カル-520（1 mm）で膜透過性のフォームを可溶化、CI-IP 3（200μM）、およびEGTA 20％のプルロニックF-127を含むジメチルスルホキシド（100 mM）を（DMSO）。 -20℃で、湿気や遮光エッペンドルフチュー​​ブとストアにこれらの試薬を分注し。 </li></ol> 3.読み込んで細胞膜透過性、カル- 520 CI-IP 3およびEGTA <ol><li>のCa 2+ -HBSSに、それぞれ、5および1μMの最終濃度になるように膜透過性カル-520及びCI-IP 3のストック溶液を希釈することにより、「ローディングバッファー」を準備します。 </li><li>吸引したCultureメディアとは、Ca 2+ -HBSS 3回メディアを交換することによって、細胞をリンス。 </li><li>のCa 2+ -HBSSを取り外して、暗闇の中で、室温で60分間ローディングバッファーで細胞を培養する。 </li><li>ローディングバッファーを除去し、Ca 2+の-HBSS 3回メディアを交換することによって、細胞をリンス。 <ol><li>必要であれば、この段階で、その後負荷のCa 2+ -HBSSで5μMの最終濃度に原液を希釈することによってEGTA / AMを持つ細胞とは、暗闇の中で、室温で30〜60分間細胞をインキュベート。このインキュベーションの後、3.5のステップに進む前に、Ca 2+の-HBSSで細胞を3回すすいでください。 </li></ol></li><li>ロードされた試薬の脱エステル化を可能にするために30分間のCa 2+ -HBSSで細胞を培養する。 </li><li>イメージングの直前に、最終インキュベーション中に風呂に漏れた可能性のある染料を除去するために、「新鮮な」のCa 2+ -HBSSでのCa 2+ -HBSSを交換してください。 </li></ol> 4.のCa 2+ </sup&gt;画像取得<ol><li> 100X APO TIRF目標（NA 1.49）上に浸漬油の小滴を置きます。 </li><li>倒立顕微鏡のステージ上での結像の皿をマウントし、透過光を用いて、焦点に細胞をもたらす。なお、記録時の移動を防止するために、撮像皿を確保することが重要である。 </li><li>高速EMCCDカメラを使用して発せられる蛍光（λ&gt; 510 nm）をカル-520を励起し、収集するために、488nmレーザーで細胞を照らす。 注：顕微鏡を操作するソフトウェアパッケージは、ユーザが、レーザビームのいずれか（「WF」励起用）より中央または（TIRF励起用）は、対物背面開口部の極端なエッジで導入されることを可能にする集束レンズを翻訳することができる。 </li><li> EMCCDソフトウェアを使用して、ローカルのCa 2+のイベントをキャプチャするために必要な時間分解能でデータを収集するために、完全な512×512画素からの撮像視野を減らす。 注：たとえば、中央クワッド256×256ピクセルの買収は、66 fpsに取得率を高速化します。さらに、単離されたクロップ·モード機能を使用して500 fpsにEMCCDカメラのフレームレートを増加させることも可能である。 </li><li>自動的に、ベースラインアクティビティの数秒を記録し、細胞に紫外線フラッシュを提供し、別の10〜30秒の記録を継続してソフトウェアを設定します。 NOTE：UVフラッシュ、顕微鏡の背面ポートにおける反射ダイクロイックミラーUVを通して導入キセノンアーク光源を用いて送達される。 UVフラッシュの持続時間と強度は、地元のCa 2+イベントの所望の周波数を呼び起こすために経験的に調整されている。 </li><li>オフライン分析のための画像スタックなどのファイルに保存する。 </li></ol> 5.自動化のCa 2+画像解析注：これは、表示プロセスと多くの商用ソフトウェアパッケージを使用して、キャプチャしたデータを分析することが可能である。しかし、我々は急速に識別ANを自動化するためのアルゴリズムを開発した地元のCa 2+シグナルのd分析。このアルゴリズムで使用される空間的および時間的フィルタの詳細な説明は、ΔF/ F 0と識別/分析ルーチンの発生が11に見出すことができる。このアルゴリズムは、オープンソースソフトウェアプラットフォームのPythonで実行するために開発された、対応する著者（ismith@uci.edu）を電子メールで送信することにより、一緒にサンプル実験データと詳細な取扱説明書を得ることができる。 <ol><li>マルチプレーン.TIFFファイル形式にカスタム書かれたアルゴリズムにインポートするファイルを変換します。 </li><li>解析アルゴリズムを含むフォルダを見つけてダブルRUN.EXEをクリックします。 </li><li>分析されるべき.TIFFファイルを選択します。 </li><li> [開く]ダイアログボックスの[解析パラメータを選択してください。サンプルデータのデフォルトのパラメータについて、図2Aを参照のこと。 </li><li> nとし、視野の部分にカーソルを移動させるのいずれかによって画像スタックからオフセットされる黒レベルを決定する細胞が含まれている（ 図2Bを参照）、または手動で「セットブラックレベル」プロンプトを使用して黒レベルを入力することにより、OT。 </li><li>ソフトウェアによる分析（ 図2C-F）以下の画面上に4つのウィンドウを観察します。 Cは、分析された細胞からの蛍光を安静時のモノクロ画像である。この画像に重畳白い四角はイベントに備えた2次元ガウス関数の重心位置として決定し、イベントの場所である。 </li><li>各イベントの場所をクリックするか、イベント間のサイクルにカーソルキーを押してください。そのようにこれらの各サイトでのバックグラウンドを差し引い、ガウシアン平滑化蛍光比の変化（ΔF/ F 0）を実行するとウィンドウDに更新する メモ：Redイベントが隣接する部位に局在活動から「ブリードスルー」からその特定のサイトから発信していないと判断された強調した。選択された部位での蛍光シグナルの検出を超えた場合に低い青のトレースを示ししきい値は、黒い線のに対し、（イベントを強調し赤に相当する）、その特定のサイトから発信するイベントを識別します。 </li><li>赤をクリックしてイベントの時間発展を表示するウィンドウのE、およびイベントの空間プロファイルが一緒にフィットガウス関数の空間プロファイルで、その時間経過にわたって平均化され表示されたウィンドウFを更新するためにイベントを強調した。 </li><li>手動での成果物は、分析から除外することができるように特定されたイベントを確認します。右の赤いをクリックして、このようなイベントを削除するには、イベントを強調した。 注：我々の手では、単一のIP 3 Rチャネルを通じたCa 2+フラックスは約0.11ΔF/ F 0で信号を連想させるので、これは偽陽性である可能性が高いよりも、任意の検出された「イベント」かなり小さい。 </li><li>目的の細胞の周りに描画し、「保存CellRを選択することで、セルごとに、またはエクスポートデータ」をExcelに保存」を選択してデータをエクスポート17 ;. 注：データは元の画像スタックと同じフォルダに保存されます。 </li></ol>

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The authors declare that they have no competing financial interests.

私たちはここに記述し、蛍光Ca 2+の指標を用いて培養された哺乳動物細胞中で地元のCa 2+イベントを画像化するためのプロトコル。さらに、我々は、取得したデータの識別および分析を自動化する直感的なユーザーインターフェースでアルゴリズムを記述する。ここで説明する手順は、蛍光Ca 2+のインジケーターカル-520が、例えば、Fluo-3、Fluo-4のような他の多くのCa <su...

カルシウムイオン（Ca 2+が ）普遍的に遺伝子発現、分泌およびシナプス可塑性1における長期的な変化を含む、生物学的プロセスの多様な範囲を調節。 Ca 2+のような多様な方法で行動できるような一つの方法は、Ca 2+の異なる空間的·時間的パターンを介して行われ、細胞が生成することができます通知します。細胞質ゾルの例グローバル標高平滑筋組織2のに対し、小さい内の[Ca 2+]トリガー収縮、ローカライズされた一過性の上昇（ローカルのCa 2+のミクロドメイン）の場合は学習と記憶3に不可欠な遺伝子発現を刺激する。 無料のサイトゾルは、の[Ca 2+]静止時〜100 nmで維持されるが、急速に細胞膜内とすることにより位置のCa 2+透過性イオンチャネルを通じて細胞質ゾルへのCa 2+の流入、以下のいくつかのマイクロモル濃度に上昇することができます細胞内sからのCa 2+の遊離tores。私たちの研究室では、小胞体（ER）膜に存在するのCa 2+放出チャネルを形成する、イノシトール1,4,5-三リン酸受容体（IP 3 R）に焦点を当てています。受容体のサイトを活性化、細胞質ゾルに両方のIP 3およびCa 2+が結合すると、IP 3 Rチャンネルは、Ca 2+が ER内腔内に隔離遊離するために開きます。 Ca 2+の放出が空間的に（Ca 2+のパフ4）のCa 2+のローカルサイトゾルのミクロドメインを生成するために、IP 3 Rの小さなクラスタに制限されたままであってもよいか、IP 3 Rの隣のクラスタの近接度に応じて、かもしれないのCa 2+誘導性のCa 2+ -放出（CICR）5,6のプロセスを介して複数のパフサイトを補充することによって、細胞全体に伝播。 高度な顕微鏡imagiと相まってツィン7ロジャーによって開発された蛍光小分子のCa 2+指示色素の導入、技術ngを、大幅のCa 2+シグナル伝達の我々の理解を促進してきた。顕微鏡検査のために使用されるカメラの最近の進歩は今そのような前例のない空間および時間分解能でパフなどの一時ローカルのCa 2+イベントを撮像することができます。現在利用可能なEMCCDカメラは、&gt; 500フレーム秒-1数（fps）と相補型金属酸化物半導体の新世代で128×128画素の画像化を可能にする（CMOS）カメラは、わずかに高い犠牲にしてより高い画素解像度、さらに速い速度を提供ノイズレベル。全反射（TIRF）顕微鏡法と併せて、画像を参照する単一のCa 2+チャネルイベント8,9可能である。実行不可能な手動処理、視覚的識別および分析をレンダリングし、自動化されたアルゴリズムの開発に責任を置く大規模なデータセット（毎分約 1Gビット）を発生しながら、このアプローチは、同時にチャネル/イベント数百の画像化を可能にする。 2+指標を用いて、無傷の哺乳動物細胞でのローカルのCa 2+シグナルを画像化するための手順およびプロトコルを提示する。今後は、TIRF、従来の広視野落射蛍光（WF）顕微鏡の両方によって画像化ローカルのCa 2+イベントの識別と分析を自動化し、オープンソース環境Pythonで開発したアルゴリズムを実証する。我々はIPのCa 2+シグナルをと生成さ3のコンテキストでこれらのアプローチを説明したが、彼 ​​らはの[Ca 2+]のCa様々ないずれかの表面に位置2+透過性イオンチャネルを発散する細胞質ゾルの局所的な変化を研究するために容易に適している膜または細胞内小器官8-10。

<table border="0" cellpadding="0" cellspacing="0" width="1055">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:813px;">Name</td>
			<td style="width:124px;">Company</td>
			<td style="width:119px;">Catalogue No.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Human Neuroblastoma SH-SY5Y cells</td>
			<td>ATCC</td>
			<td>CRL-2266</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Cal-520/AM</td>
			<td>AAT Bioquest Inc.</td>
			<td>21130</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">ci-IP3 (D-23-O-Isopropylidene-6-O-(2-nitro-4.5-dimethoxy)benzyl-myo-Inositol 145-trisphosphate-Hexakis(propionoxymethyl)</td>
			<td>SiChem</td>
			<td>cag-iso-2-145-10</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">DMSO/20% pluronic F127</td>
			<td>Invitrogen</td>
			<td>P-3000MP</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">EGTA/AM</td>
			<td>Invitrogen</td>
			<td>E-1219</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">35 mm glass-bottom imaging dishes</td>
			<td>MatTek</td>
			<td>P35-1.5-14-C</td>
		</tr>
	</tbody>
</table>

imaging local ca2+ signals in cultured mammalian cells

細胞質ゾルのCa 2+イオンは、広範囲の遺伝子転写、電気的興奮性細胞増殖のようなプロセスを制御する、ほ ​​ぼすべての細胞型における細胞活性の多くの側面を調節する。のCa 2+シグナル伝達の多様性と特異性は、地元の過渡のCa 2+マイクロドメイン分の期間にわたって発生する細胞全体の振動と波に至るまでのCa 2+シグナルは、異なる時間と空間スケールの上に行動するために生成されるメカニズムから派生（Ca 2+のパフ）持続的なミリ秒。電子の最近の進歩は、CCD（EMCCD）カメラは今&gt; 500フレーム秒-1（FPS）のレートで128×128ピクセル空間分解能で地元のCa 2+シグナルの画像化を可能に掛けた。このアプローチは、高度に並列であり、単一の実験でチャンネルやパフサイトの何百もの同時モニタリングを可能にします。しかし、膨大な量のデータが生成された（ 約 ​​1 GBのPER分）実行不可能なローカルのCa 2+のイベントの視覚的な識別と分析をレンダリングします。ここでは説明し、取得、検出のための方法が示され、かつ広視野落射蛍光（WF）と全反射の両方を使用したCa 2+指標を搭載し、無傷の哺乳動物細胞内でのCa 2+シグナルを媒介3ローカルIPの分析蛍光（TIRF）顕微鏡。さらに、我々は、これらのローカルのCa 2+シグナルの同定および分析を自動化するオープンソースのソフトウェア環境のPythonの中で開発したアルゴリズムを記述します。アルゴリズムは、サブピクセル解像度でのCa 2+放出の部位を局在化する。データのユーザーレビューを可能にする。エクセル互換テーブルの振幅および動力学的データと共に蛍光比信号の時間系列を出力する。

図1Aはまた、ciは、IP 3を装填したヒト神経芽細胞腫SH-SY5Y細胞におけるカル-520蛍光休止のWF画像を示す。フォト·リリースに100ミリ秒のUVフラッシュへのこれらの細胞の曝露は、I-IP 3は、（ 図1Aに白丸で示される）別個の部位での一過性のCa 2+パフを誘発した。これらの部 ​​位で測定された蛍光トレースはゆっくりとリリースサ?...

Watch this Scientific Journal Video about Imaging Local Ca2+ Signals in Cultured Mammalian Cells at JoVE.com

Imaging Local Ca2+ Signals in Cultured Mammalian Cells

Here we present techniques for imaging local IP3-mediated Ca2+ events using fluorescence microscopy in intact mammalian cells loaded with Ca2+ indicators together with an algorithm that automates identification and analysis of these events.

イメージングローカルCA<sup&gt; 2+</sup&gt;培養哺乳動物細胞内シグナル

Cytosolic Ca2+ ions regulate numerous aspects of cellular activity in almost all cell types, controlling processes as wide-ranging as gene transcription, ...

imaging-local-ca2-signals-in-cultured-mammalian-cells

Research

JoVE Journal

Biology

Imaging Local Ca2+ Signals in Cultured Mammalian Cells

10.7K ビュー.  University of California, Irvine. Here we present techniques for imaging local IP3-mediated Ca2+ events using fluorescence microscopy in intact mammalian cells loaded with Ca2+ indicators together with an algorithm that automates identification and analysis of these events.

ビデオ: Imaging Local Ca2+ Signals in Cultured Mammalian Cells

Long-term Imaging Mammalian Cells using Wide-Field Microscopy

Actually what I'm gonna do, mount it in here first and then swap out You. So now I'm gonna aspirate try and be as gentle as possible.Okay. A few seconds just holding.Okay.Alright.So the important features of our lifestyle imaging grid are that, so it's an inverted scope, which means the objective, the samples here in the objective is underneath. So the objective is pointing up and the whole scope, or practically the whole, practically the whole scope, including the objectives and the sample are at 37 degrees. So everything in this plastic box is at 37 degrees.And right on top of the stage we have an air and CO2 mix. That is 5%CO2. So the idea is that the sample is actually in a cell, it's like a cell incubator.And so we have, this is our mixer for the air and the CO2 and, and it gets humidified and heated and then piped onto the, the sample on the stage.Okay. And today we're just gonna be doing fluorescence one channel GFP fluorescence. This is the hose that the CO2 and 5%CO2 goes in and it just fits into the stage holder.That's important. And then we can close these, take these down, and then we go to our first position. And what I'm gonna do is go to the first field, which is my control sample, and I'll pick positions based on what I see on the screen.So I just make sure I actually look into the microscope in each new, well, because the focal plane for each of the wells is different, the, the dish is not perfectly flat on the bottom. So you will need to make fine adjustments when you move from well to the well. So right now I'm on the first, well, what I'll do is I'll focus, so I just hit, I just told, I just turned on the light, the transmitted light for the microscope.And I have make sure all the light is going to the eye pieces. And so I just look in, make sure I get a nice clean field. And then what I'll do is turn that light off, turn the fluorescence light on, make sure the cells that I'm looking at look healthy and they're not apoptotic.And, and I turn that off. And what I do next is send, so now I'm gonna start picking positions, which means I have to te send the light path to the camera. This is the camera right here.So I tell the microscope to send all the camera, they don't see anything in the eye pieces. What I'll do is in the software controlling the microscope, I'll choose the right filter set, which for our purposes is psy. And then set an exposure time.And I know these cells very well and I know that they take a 0.2 second exposure time. So I tell, that's what I tell the software to do. And what I'll do is hit focus.This is, and it's basically just alive. The, A light will turn on and you can, oh, I don't know if you can see cells, but the reason this is a good field is because there's, all the cells are, even in terms of their fluorescence, There are no apoptotic cells. Apoptotic cells tend to be very bright and there's no dirt or schmutz in the field.And you can see that they're actually, this is a metaphase cell and that's a metaphase cell, that's a cell that's probably just exited mitosis. And I can just tell that because it looks like those are, those two sets of chromatin are very nicely oriented to each other. Like they just exited an face.So that's a good field. So, and now that I know that the exposure time and the filter set is correct, and this is gonna be software specific, I'll go and I'll take positions and now the software has memorized the X, Y, Z position of that field. And then when I do pick another field, it's, and I'll, so when I'm picking, when I'm picking new fields, but in the same, well, I'll use the, I'll move the i'll, I'll turn the shutter, I'll open the shutter and I'll look to see what I see on the screen and I'll pick fields based on that versus looking in the field.So I don't see any of my tonics in there. But again, even nicely centered, these cells will go through my PS I continue, here's a good example. Here's a good example of what I would avoid that, see how bright that is?That's very bright. That's probably remnants of an apoptotic cell. And the reason I would avoid that is because since it's so bright, when the software auto focuses, it will autofocus just on that and it won't be in the same plane as all these other cells.And so I won't get any information from that field. That looks nice. There's a, this is a pro metaphase right here, That's A metaphase.So, and I'm gonna take three positions per well. So that was three positions and now I'm going to go to my next Well, so you can, so what I will probably do is take images every 10 minutes. So it's a compromise.Lifestyle imaging is always a compromise, right? You have to image, you have to keep the cells healthy, especially if you're interested in mitosis. So you have to minimize their exposure to the fluorescent line.And, but you wanna get information. So you have to take images, you have to, so you have to compromise, you have to make a choice about what you want to capture, what kind of information you wanna capture. For our purposes, mitosis tends to take about an hour.So if we're taking 10 minute intervals, that's pretty good. We see prophase, we see metaphase, we see anaphase, and we can, we can see when there are, there are treatments or drugs or siRNAs that affect those specific cell cycle stages. So for our purposes, that's enough, but we always want more.We always want more positions or finer time and interval or something like that. So it's a compromise. So, and then I'll hit start.And so our software, it does an autofocusing pass on the first pass. So once I hit start, it should start auto autofocusing and you'll see the shutter open, open and close between auto focusing. So I'll hit start.So that's the shutter opening and closing. The Z motor is engaging and it's actually trying to find the plane with the most contrast, which will be the most in focus. You can actually see on the screen going in and out of finding the best plane of focus that might be worrisome.So what it does is it, it drives the Z motor to find the best, the most in focus plane focus, well the most in image. And then it acquires picture there and then it learns that Z position. And then we'll use that Z position for the next 12 passes.And then we'll do the auto focusing pass again. What Kind of experiments do they do? Okay, so our lab is mostly interested in understanding what regulates mitic progression, or at least I'm most interested in understanding that.So with live cell imaging and especially our multi position, long-term imaging scope, you can take, you can film cells for two or three days entering anding mitosis, and you can image multiple rounds of mitosis so you can understand. And then you can put drugs or RNAs or any kind of perturbations on the cells that you would like to study. So you can understand how, how those drugs or, or genes are, are important in regulating mitotic progression.Because it's not fixed cell work and live cell work, you can understand what, when you need to have a perturbation to affect mitosis or what stage of mitosis is affected. So it's really powerful in that respect. What, what are the main technical elements of this experiments?What are the possible problems? Well, the biggest problem besides getting the rig set up, getting the rig set up is not trivial. A lot of people have the rig, but just making sure it works well for your application.The financial element is not, you know, is not small. So there's the setting up of the apparatus and then, and then once you gather the data, there's a real data analysis issue. It takes these movie, if, so, if you're gathering 40 movies each with 30 cells, so you have 40 in 40 fields that you just filmed and each of those fields has 30 cells, then you have to sit down with each one of those movies and look at each one of those cells in that movie.So it takes a really long time to do data analysis. And that's, so it takes a week to analyze data that it took you two days to collect. So there's a, that's a very big obstacle in terms of gathering lots of data.So it's not, while it's high throughput data collection, it's not high throughput analysis. So what would you make to make this experiment really high throughput? So our lab is in the process of developing a program that does the data analysis automatically.And it's a pretty decent program. It's not perfect. The human eye is always better, but it's getting there.So What are the interesting application of this experiment? Maybe other fields you can mention? Besides cell division?You mean for the, oh, for the live cell imaging? Yes.Well, you can do cell motility assays. You can, depending on the, the microscopy that's involved, you can, you know, look at how cells, you could look at tumor development if you really wanted to.But there, you, you're, if as long as you have the right imaging set up, you can, you're pretty much not limited in terms of anything. Our scope happens to be just a wide field and we use 20 by 20 x objective. So it's a pretty low resolution set up, but that's sufficient for what we need to see.So there are, but there definitely aren't, you wouldn't be limited. Anything that has any dynamic kind of experiment, which is biology, it would be, would really benefit from lifestyle imaging. So calcium imaging, although you couldn't do it on our apparatus, that's a live cell.You definitely need live cell imaging for that. Like I said, patient assays, motility assays, those kinds of things would really benefit from live cell imaging. Would you like to tell a few words about your previous experience?How long do you work on these techniques? What do you you work on before? Wow.So in my PhD I didn't work.I did a lot of confocal microscopy, but no lifestyle imaging. And so during my postdoc I was, I helped Dr.King get this apparatus that, that we just used to set up these fragment, get that up and running. And, and so during my postdoc, I had a lot of experience with both widefield with TimeLapse imaging on our scope, which is the widefield and also TimeLapse imaging with confocal microscopy.And I would say that it's really powerful. You get a lot of information, but it's not easy to get working perfectly. So it really requires a lot of attention and a lot of attention to details at every little step of the process.And, and then you still have problems. So it's a tough application, but you can really get, if, if it's what you need to have to, to study your problem, your scientific problem, then it, it's invaluable in that respect, but it's tough. So find someone who knows what they're doing and use them.That's my advice. So good.

広視野顕微鏡を用いて長期的なイメージング哺乳類細胞

生物学

Live Imaging of Dense-core Vesicles in Primary Cultured Hippocampal Neurons

Observing and characterizing dynamic cellular processes can yield important information about cellular activity that cannot be gained from static images.  Vital fluorescent probes, particularly green fluorescent protein (GFP) have revolutionized cell biology stemming from the ability to label specific intracellular compartments and cellular structures. For example, the live imaging of GFP (and its spectral variants) chimeras have allowed for a dynamic 
analysis of the cytoskeleton, organelle transport, and membrane dynamics in a multitude of organisms and cell types [1-3].  Although live imaging has become prevalent, this approach still poses many technical challenges, particularly in primary cultured neurons.  One challenge is the expression of GFP-tagged proteins in post-mitotic neurons; the other is the ability to capture fluorescent images while minimizing phototoxicity, photobleaching, 
and maintaining general cell health.  Here we provide a protocol that describes a lipid-based transfection method that yields a relatively low transfection rate (~0.5%), however is ideal for the imaging of fully polarized neurons.  A low transfection rate is essential so that single axons and dendrites can be characterized as to their orientation to the cell body to confirm directionality of transport, i.e., anterograde v. retrograde.  Our approach to imaging 
GFP expressing neurons relies on a standard wide-field fluorescent microscope outfitted with a CCD camera, image capture software, and a heated imaging chamber. We have imaged a wide variety of organelles or structures, for example, dense-core vesicles, mitochondria, growth cones, and actin without any special optics or excitation requirements other than a fluorescent light source. Additionally, spectrally-distinct, fluorescently 
labeled proteins, e.g., GFP and dsRed-tagged proteins, can be visualized near simultaneously to characterize co-transport or other coordinated cellular events.  The imaging approach described here is flexible for a variety of imaging applications and can be adopted by a laboratory for relatively little cost provided a microscope is available.

Live cell imaging is of particular utility when studying the dynamics of organelle trafficking. Here we describe a protocol for live imaging of dense-core vesicles in cultured neurons using wide-field fluorescence microscopy. This protocol is flexible and can be adapted to image other organelles such as mitochondria, endosomes, and peroxisomes.

初代培養海馬ニューロンにおける高密度コア小胞のライブイメージング

Observing and characterizing dynamic cellular processes can yield important information about cellular activity that cannot be gained from static images.  ...

Techniques for Imaging Ca2+ Signaling in Human Sperm

Fluorescence microscopy of cells loaded with fluorescent, Ca2+-sensitive dyes is used for measurement of spatial and temporal aspects of Ca2+ signaling in live cells. Here we describe the method used in our laboratories for loading suspensions of human sperm with Ca2+-reporting dyes and measuring the fluorescence signal during physiological stimulation. Motile cells are isolated by direct swim-up and incubated under capacitating conditions for 0-24 h, depending upon the experiment. The cell-permeant AM (acetoxy methyl ester) ester form of the Ca2+-reporting dye is then added to a cell aliquot and a period of 1 h is allowed for loading of the dye into the cytoplasm. We use visible wavelength dyes to minimize photo-damage to the cells, but this means that ratiometric recording is not possible. Advantages and disadvantages of this approach are discussed. During the loading period cells are introduced into an imaging chamber and allowed to adhere to a poly-D-lysine coated coverslip. At the end of the loading period excess dye and loose cells are removed by connection of the chamber to the perfusion apparatus. The chamber is perfused continuously, stimuli and modified salines are then added to the perfusion header. Experiments are recorded by time-lapse acquisition of fluorescence images and analyzed in detail offline, by manually drawing regions of interest. Data are normalized to pre-stimulus levels such that, for each cell (or part of a cell), a graph showing the Ca2+ response as % change in fluorescence is obtained.

Techniques for Imaging Ca2+ Signaling in Human Sperm

Stimulus-evoked [Ca2+]i signals of individual human sperm are assessed. Motile cells are loaded with Ca2+-sensitive fluorescent dye (AM-ester method) and immobilised in a perfusable chamber. Cells are imaged by time-lapse fluorescence microscopy and stimulated via the perfusing medium. Responses of single cells (or regions) are analysed offline using Excel.

イメージングカルシウムのためのテクニック 2 +人間の精子でシグナリング

Fluorescence microscopy of cells loaded with fluorescent, Ca2+-sensitive dyes is used for measurement of spatial and temporal aspects of Ca2+ signaling in ...

MISSION esiRNA for RNAi Screening in Mammalian Cells

RNA interference (RNAi) is a basic cellular mechanism for the control of gene expression. RNAi is induced by short double-stranded RNAs also known as small interfering RNAs (siRNAs). The short double-stranded RNAs originate from longer double stranded precursors by the activity of Dicer, a protein of the RNase III family of endonucleases. The resulting fragments are components of the RNA-induced silencing complex (RISC), directing it to the cognate target mRNA. RISC cleaves the target mRNA thereby reducing the expression of the encoded protein1,2,3. RNAi has become a powerful and widely used experimental method for loss of gene function studies in mammalian cells utilizing small interfering RNAs.
Currently two main methods are available for the production of small interfering RNAs. One method involves chemical synthesis, whereas an alternative method employs endonucleolytic cleavage of target specific long double-stranded RNAs by RNase III in vitro. Thereby, a diverse pool of siRNA-like oligonucleotides is produced which is also known as endoribonuclease-prepared siRNA or esiRNA. A comparison of efficacy of chemically derived siRNAs and esiRNAs shows that both triggers are potent in target-gene silencing. Differences can, however, be seen when comparing specificity. Many single chemically synthesized siRNAs produce prominent off-target effects, whereas the complex mixture inherent in esiRNAs leads to a more specific knockdown10.
In this study, we present the design of genome-scale MISSION esiRNA libraries and its utilization for RNAi screening exemplified by a DNA-content screen for the identification of genes involved in cell cycle progression. We show how to optimize the transfection protocol and the assay for screening in high throughput. We also demonstrate how large data-sets can be evaluated statistically and present methods to validate primary hits. Finally, we give potential starting points for further functional characterizations of validated hits.

Here we use a human esiRNA library in a high-throughput screen for genes involved in cell division. We demonstrate how to set up and conduct an esiRNA screens, as well as how to analyze and validate the results.

哺乳動物細胞におけるRNAiスクリーニングのためのミッションesiRNA

RNA interference (RNAi) is a basic cellular mechanism for the control of gene expression. RNAi is induced by short double-stranded RNAs also known as ...

Fluorescence-based Measurement of Store-operated Calcium Entry in Live Cells: from Cultured Cancer Cell to Skeletal Muscle Fiber

Store operated Ca2+ entry (SOCE), earlier termed capacitative Ca2+ entry, is a tightly regulated mechanism for influx of extracellular Ca2+ into cells to replenish depleted endoplasmic reticulum (ER) or sarcoplasmic reticulum (SR) Ca2+ stores1,2. Since Ca2+ is a ubiquitous second messenger, it is not surprising to see that SOCE plays important roles in a variety of cellular processes, including proliferation, apoptosis, gene transcription and motility. Due to its wide occurrence in nearly all cell types, including epithelial cells and skeletal muscles, this pathway has received great interest3,4. However, the heterogeneity of SOCE characteristics in different cell types and the physiological function are still not clear5-7.
The functional channel properties of SOCE can be revealed by patch-clamp studies, whereas a large body of knowledge about this pathway has been gained by fluorescence-based intracellular Ca2+ measurements because of its convenience and feasibility for high-throughput screening. The objective of this report is to summarize a few fluorescence-based methods to measure the activation of SOCE in monolayer cells, suspended cells and muscle fibers5,8-10. The most commonly used of these fluorescence methods is to directly monitor the dynamics of intracellular Ca2+ using the ratio of F340nm and F380nm (510 nm for emission wavelength) of the ratiometric Ca2+ indicator Fura-2. To isolate the activity of unidirectional SOCE from intracellular Ca2+ release and Ca2+ extrusion, a Mn2+ quenching assay is frequently used. Mn2+ is known to be able to permeate into cells via SOCE while it is impervious to the surface membrane extrusion processes or to ER uptake by Ca2+ pumps due to its very high affinity with Fura-2. As a result, the quenching of Fura-2 fluorescence induced by the entry of extracellular Mn2+ into the cells represents a measurement of activity of SOCE9. Ratiometric measurement and the Mn+2 quenching assays can be performed on a cuvette-based spectrofluorometer in a cell population mode or in a microscope-based system to visualize single cells. The advantage of single cell measurements is that individual cells subjected to gene manipulations can be selected using GFP or RFP reporters, allowing studies in genetically modified or mutated cells. The spatiotemporal characteristics of SOCE in structurally specialized skeletal muscle can be achieved in skinned muscle fibers by simultaneously monitoring the fluorescence of two low affinity Ca2+ indicators targeted to specific compartments of the muscle fiber, such as Fluo-5N in the SR and Rhod-5N in the transverse tubules9,11,12.

The extent of store-operated Ca2+ entry (SOCE) can be monitored using fluorescent Ca2+ indicators. Mn2+ quenching of such indicators assays SOCE in cultured cells and skeletal muscle fibers. A technique allowing spatial and temporal resolution of SOCE by confocal imaging of mechanically skinned muscle fibers is also described.

生細胞におけるストア作動性カルシウムエントリの蛍光ベースの測定：培養癌細胞から骨格筋線維に

Store operated Ca2+ entry (SOCE), earlier termed capacitative Ca2+ entry, is a tightly regulated mechanism for influx of extracellular Ca2+ into cells to ...

Analysis of Cell Cycle Position in Mammalian Cells

The regulation of cell proliferation is central to tissue morphogenesis during the development of multicellular organisms. Furthermore, loss of control of cell proliferation underlies the pathology of diseases like cancer. As such there is great need to be able to investigate cell proliferation and quantitate the proportion of cells in each phase of the cell cycle. It is also of vital importance to indistinguishably identify cells that are replicating their DNA within a larger population. Since a cell&prime;s decision to proliferate is made in the G1 phase immediately before initiating DNA synthesis and progressing through the rest of the cell cycle, detection of DNA synthesis at this stage allows for an unambiguous determination of the status of growth regulation in cell culture experiments.
DNA content in cells can be readily quantitated by flow cytometry of cells stained with propidium iodide, a fluorescent DNA intercalating dye. Similarly, active DNA synthesis can be quantitated by culturing cells in the presence of radioactive thymidine, harvesting the cells, and measuring the incorporation of radioactivity into an acid insoluble fraction. We have considerable expertise with cell cycle analysis and recommend a different approach. We Investigate cell proliferation using bromodeoxyuridine/fluorodeoxyuridine (abbreviated simply as BrdU) staining that detects the incorporation of these thymine analogs into recently synthesized DNA. Labeling and staining cells with BrdU, combined with total DNA staining by propidium iodide and analysis by flow cytometry1 offers the most accurate measure of cells in the various stages of the cell cycle. It is our preferred method because it combines the detection of active DNA synthesis, through antibody based staining of BrdU, with total DNA content from propidium iodide. This allows for the clear separation of cells in G1 from early S phase, or late S phase from G2/M. Furthermore, this approach can be utilized to investigate the effects of many different cell stimuli and pharmacologic agents on the regulation of progression through these different cell cycle phases.
In this report we describe methods for labeling and staining cultured cells, as well as their analysis by flow cytometry. We also include experimental examples of how this method can be used to measure the effects of growth inhibiting signals from cytokines such as TGF-&beta;1, and proliferative inhibitors such as the cyclin dependent kinase inhibitor, p27KIP1. We also include an alternate protocol that allows for the analysis of cell cycle position in a sub-population of cells within a larger culture5. In this case, we demonstrate how to detect a cell cycle arrest in cells transfected with the retinoblastoma gene even when greatly outnumbered by untransfected cells in the same culture. These examples illustrate the many ways that DNA staining and flow cytometry can be utilized and adapted to investigate fundamental questions of mammalian cell cycle control.

Determining the cell cycle position of a population of cells, or understanding how signals affect proliferation, can be readily measured by flow cytometry using this protocol. We report a simple experimental approach to staining cells and quantifying their position in the cell cycle.

哺乳動物細胞における細胞周期の位置の解析

The regulation of cell proliferation is central to tissue morphogenesis during the development of multicellular organisms. Furthermore, loss of control of ...

Automated Analysis of Dynamic Ca2+ Signals in Image Sequences

Intracellular Ca2+ signals are commonly studied with fluorescent Ca2+ indicator dyes and microscopy techniques. However, quantitative analysis of Ca2+ imaging data is time consuming and subject to bias. Automated signal analysis algorithms based on region of interest (ROI) detection have been implemented for one-dimensional line scan measurements, but there is no current algorithm which integrates optimized identification and analysis of ROIs in two-dimensional image sequences. Here an algorithm for rapid acquisition and analysis of ROIs in image sequences is described. It utilizes ellipses fit to noise filtered signals in order to determine optimal ROI placement, and computes Ca2+ signal parameters of amplitude, duration and spatial spread. This algorithm was implemented as a freely available plugin for ImageJ (NIH) software. Together with analysis scripts written for the open source statistical processing software R, this approach provides a high-capacity pipeline for performing quick statistical analysis of experimental output. The authors suggest that use of this analysis protocol will lead to a more complete and unbiased characterization of physiologic Ca2+ signaling.

Automated Analysis of Dynamic Ca2+ Signals in Image Sequences

Here a novel region of interest analysis protocol based on sorting best-fit ellipses assigned to regions of positive signal within two-dimensional time lapse image sequences is demonstrated. This algorithm may enable investigators to comprehensively analyze physiological Ca2+ signals with minimal user input and bias.

ダイナミックカルシウムの自動分析<sup&gt; 2 +</supイメージシーケンス内の&gt;の信号

Intracellular Ca2+ signals are commonly studied with fluorescent Ca2+ indicator dyes and microscopy techniques. However, quantitative analysis of Ca2+ ...

siRNA Screening to Identify Ubiquitin and Ubiquitin-like System Regulators of Biological Pathways in Cultured Mammalian Cells

Post-translational modification of proteins with ubiquitin and ubiquitin-like molecules (UBLs) is emerging as a dynamic cellular signaling network that regulates diverse biological pathways including the hypoxia response, proteostasis, the DNA damage response and transcription.&#160; To better understand how UBLs regulate pathways relevant to human disease, we have compiled a human siRNA &#8220;ubiquitome&#8221; library consisting of 1,186 siRNA duplex pools targeting all known and predicted components of UBL system pathways. This library can be screened against a range of cell lines expressing reporters of diverse biological pathways to determine which UBL components act as positive or negative regulators of the pathway in question.&#160; Here, we describe a protocol utilizing this library to identify ubiquitome-regulators of the HIF1A-mediated cellular response to hypoxia using a transcription-based luciferase reporter.&#160; An initial assay development stage is performed to establish suitable screening parameters of the cell line before performing the screen in three stages: primary, secondary and tertiary/deconvolution screening. &#160;The use of targeted over whole genome siRNA libraries is becoming increasingly popular as it offers the advantage of reporting only on members of the pathway with which the investigators are most interested.&#160; Despite inherent limitations of siRNA screening, in particular false-positives caused by siRNA off-target effects, the identification of genuine novel regulators of the pathways in question outweigh these shortcomings, which can be overcome by performing a series of carefully undertaken control experiments.

Here, we describe a methodology to perform a targeted siRNA &#8220;ubiquitome&#8221; screen to identify novel ubiquitin and ubiquitin-like regulators of the HIF1A-mediated cellular response to hypoxia.&#160; This can be adapted to any biological pathway where a robust read out of reporter activity is available.

培養哺乳動物細胞内の生物学的経路のユビキチンおよびユビキチン様システムレギュレータを識別するために、siRNAのスクリーニング

Post-translational modification of proteins with ubiquitin and ubiquitin-like molecules (UBLs) is emerging as a dynamic cellular signaling network that ...

Measurement of Heme Synthesis Levels in Mammalian Cells

Heme serves as the prosthetic group for a wide variety of proteins known as hemoproteins, such as hemoglobin, myoglobin and cytochromes. It is involved in various molecular and cellular processes such as gene transcription, translation, cell differentiation and cell proliferation. The biosynthesis levels of heme vary across different tissues and cell types and is altered in diseased conditions such as anemia, neuropathy and cancer. This technique uses [4-14C] 5-aminolevulinic acid ([14C] 5-ALA), one of the early precursors in the heme biosynthesis pathway to measure the levels of heme synthesis in mammalian cells. This assay involves incubation of cells with [14C] 5-ALA followed by extraction of heme and measurement of the radioactivity incorporated into heme. This procedure is accurate and quick. This method measures the relative levels of heme biosynthesis rather than the total heme content. To demonstrate the use of this technique the levels of heme biosynthesis were measured in several mammalian cell lines.

Altered intracellular heme levels are associated with common diseases such as cancer. Thus, there is a need to measure heme biosynthesis levels in diverse cells. The goal of this protocol is to provide a fast and sensitive method to measure and compare the levels of heme synthesis in different cells.

哺乳動物細胞におけるヘム合成レベルの測定

Heme serves as the prosthetic group for a wide variety of proteins known as hemoproteins, such as hemoglobin, myoglobin and cytochromes. It is involved in ...

Massively Parallel Reporter Assays in Cultured Mammalian Cells

The genetic reporter assay is a well-established and powerful tool for dissecting the relationship between DNA sequences and their gene regulatory activities. The potential throughput of this assay has, however, been limited by the need to individually clone and assay the activity of each sequence on interest using protein fluorescence or enzymatic activity as a proxy for regulatory activity. Advances in high-throughput DNA synthesis and sequencing technologies have recently made it possible to overcome these limitations by multiplexing the construction and interrogation of large libraries of reporter constructs. This protocol describes implementation of a Massively Parallel Reporter Assay (MPRA) that allows direct comparison of hundreds of thousands of putative regulatory sequences in a single cell culture dish.

The genetic reporter assay is a well-established and powerful tool for dissecting the relationship between DNA sequences and their gene regulatory activities. Coupling candidate regulatory elements to reporter genes that carry identifying sequence tags enables massive parallelization of these assays.