המחברים מודים זרימת מחקר Cytometry Core בבית החולים לקרן המחקר לילדים בסינסינטי וריצ&#39;רד דימרקו, Sherree חבר, וסקוט מרדכי מחברת Amnis (חלק מEMD Milllipore) לקבלת תמיכה טכנית מומחה. עבודה זו נתמכה על ידי המכון הלאומי לבריאות מעניק K08HL088126 וR01HL116352 (TAK) וDK090971 P30 (YZ).

<ol>
	<li>McGrath, K. E., Kingsley, P. D., Koniski, A. D., Porter, R. L., Bushnell, T. P., Palis, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enucleation+of+primitive+erythroid+cells+generates+a+transient+population+of+&amp;#34;pyrenocytes&amp;#34;+in+the+mammalian+fetus.">Enucleation of primitive erythroid cells generates a transient population of &amp;#34;pyrenocytes&amp;#34; in the mammalian fetus.</a> Blood. 111, 2409-2417 (2008).</li><li>Chasis, J. A., Mohandas, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Erythroblastic+islands:+niches+for+erythropoiesis.">Erythroblastic islands: niches for erythropoiesis.</a> Blood. 112, 470-478 (2008).</li><li>Koury, S. T., Koury, M. J., Bondurant, M. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cytoskeletal+distribution+and+function+during+the+maturation+and+enucleation+of+mammalian+erythroblasts.">Cytoskeletal distribution and function during the maturation and enucleation of mammalian erythroblasts.</a> J Cell Biol. 109, 3005-3013 (1989).</li><li>Ji, P., Jayapal, S. R., Lodish, H. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enucleation+of+cultured+mouse+fetal+erythroblasts+requires+Rac+GTPases+and+mDia2.">Enucleation of cultured mouse fetal erythroblasts requires Rac GTPases and mDia2.</a> Nat Cell Biol. 10, 314-321 (2008).</li><li>Keerthivasan, G., Small, S., Liu, H., Wickrema, A., Crispino, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vesicle+trafficking+plays+a+novel+role+in+erythroblast+enucleation.">Vesicle trafficking plays a novel role in erythroblast enucleation.</a> Blood. 116, 3331-3340 (2010).</li><li>McGrath, K. E., Bushnell, T. P., Palis, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multispectral+imaging+of+hematopoietic+cells:+where+flow+meets+morphology.">Multispectral imaging of hematopoietic cells: where flow meets morphology.</a> J Immunol Methods. 336, 91-97 (2008).</li><li>Konstantinidis, D. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Signaling+and+cytoskeletal+requirements+in+erythroblast+enucleation.">Signaling and cytoskeletal requirements in erythroblast enucleation.</a> Blood. 119, 6118-6127 (2012).</li><li>Giarratana, M. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ex+vivo+generation+of+fully+mature+human+red+blood+cells+from+hematopoietic+stem+cells.">Ex vivo generation of fully mature human red blood cells from hematopoietic stem cells.</a> Nat Biotechnol. 23, 69-74 (2005).</li><li>Chen, K., Liu, J., Heck, S., Chasis, J. 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E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sensitivity+measurement+and+compensation+in+spectral+imaging.">Sensitivity measurement and compensation in spectral imaging.</a> Cytometry A. 69, 852-862 (2006).</li></ol>

המחברים מצהירים שום אינטרסים כלכליים מתחרים.

בשנים האחרונות המחקר של אנוקלאציה erythroblast צבר תאוצה גוברת שכן הוא הצעד במבחנת תרבויות erythropoiesis שהוא קשה ביותר להתרבות ביעילות על מנת להשיג ייצור של תאי דם אדומים לשעבר vivo מוצלח, בקנה מידה גדולה. עד לאחרונה, המחקר של אנוקלאציה erythroblast מנוצל מיקרוסקופיה בעיקר ה?...

בידול מסוף בתוך שושלת erythroid ביונקים מסתיים בתהליך הדרמטי של אנוקלאציה, שדרכו erythroblast אורתוכרומטי מגרש הגרעין שלה, עטוף בממברנה (pyrenocyte) 1, שהניבו reticulocyte 2. המנגנון המדויק של תהליך זה, שהוא גם הגבלת צעד שיעור מוצלח, בקנה מידה גדולה, ייצור כדוריות דם אדומים במבחנה, עדיין לא הובהר במלואו. הלוקליזציה של חלבונים ומבני מפתח בתוך erythroblasts enucleating מסתמכת על השימוש במיקרוסקופ פלואורסצנטי ואלקטרוני 3-5. תהליך מייגע זה בדרך כלל תוצאות בזיהוי של מספר מצומצם של אירועי אנוקלאציה ולא תמיד מאפשר ניתוח סטטיסטי משמעותי. הרחבת על שיטה של זיהוי erythroblast תוארה בעבר על ידי McGrath et al. 6, פיתחנו גישה חדשנית של זיהוי ולימוד אירועי אנוקלאציה ידי Multi-Spectral אמאגינג cytometry הזרימה (multiparameter הדמיה במהירות גבוהה תא בזרימה, בשיטה המשלבת מיקרוסקופ פלואורסצנטי עם cytometry זרימה) 7, אשר יכול לספק מספר מספיק של תצפיות כדי להשיג מדידות וביצוע ניתוחים סטטיסטיים. כאן, אנו מתארים שתי שיטות מבחנה הראשונות בerythropoiesis תרבות משמשות כדי לסנכרן erythroblasts ולהגדיל את ההסתברות ללכידת אנוקלאציה בעת ההערכה. לאחר מכן אנו מתארים בפירוט את ההכתמה של erythroblasts לאחר הקיבוע וpermeabilization כדי ללמוד את הלוקליזציה של חלבונים תאיים או רפסודות שומנים בדם במהלך אנוקלאציה ידי זרימת הדמיה רבת רפאים cytometry. דגימות מנוהלות על זרימת הדמיה cytometer והתאים שנאספו הם מגודרים כראוי לזהות erythroblasts אורתוכרומטי 6. אז erythroblasts אורתוכרומטי מנותחים המבוסס על היחס שלהם, כפי שהיא נמדדת בהר&quot;י brightfieldגינג, לעומת ערכם לcentroid דלתא פרמטר XY Ter119-DNA, אשר מוגדר כמרחק בין המרכזים של האזורים המוכתמים עבור Ter119 ו-DNA, בהתאמה. האוכלוסייה של תאים עם יחס נמוך וcentroid דלתא הגבוה XY Ter119/DNA היא מועשר בenucleating תאים. באמצעות wild-type (WT) erythroblasts לעומת erythroblasts עם מחיקת MX-Cre בתיווך מותנית של Rac1 על Rac2 - / - או בשילוב Rac2 - / -; Rac3 - / - רקע גנטי ופרוטוקול ניתוח הרומן הזה של זרימת הדמיה רבת רפאים cytometry, אנחנו הוכיחו לאחרונה כי אנוקלאציה דומה cytokinesis סימטרי וכי היווצרות טבעת actomyosin מוסדרת בחלקו על ידי GTPases RAC היא חשובה להתקדמות אנוקלאציה 7.

<table border="0" cellpadding="0" cellspacing="0" width="934">
	<tbody>
		<tr height="22">
			<td height="22" style="height:22px;width:363px;">&#945;MEM medium</td>
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			<td style="width:207px;">512450</td>
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		<tr height="24">
			<td height="24" style="height:24px;width:363px;">Phosphate buffered saline (PBS)</td>
			<td style="width:199px;">Hyclone (Thermo Scientific)</td>
			<td style="width:207px;">SH30028.02</td>
			<td style="width:167px;"></td>
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		<tr height="23">
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			<td style="width:207px;">SH30590.01</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:363px;">Isothesia (Isoflurane)</td>
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			<td style="width:207px;">029405</td>
			<td style="width:167px;"></td>
		</tr>
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			<td height="22" style="height:22px;width:363px;">Histopaque 1.083mg/ml</td>
			<td style="width:199px;">Sigma</td>
			<td style="width:207px;">10831</td>
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			<td height="27" style="height:27px;width:363px;">BD Pharmlyse (RBC lysis buffer)</td>
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			<td style="width:207px;">555899</td>
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			<td height="22" style="height:22px;width:363px;">Acetone</td>
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			<td style="width:207px;">534064</td>
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			<td height="29" style="height:29px;width:363px;">Formaldehyde</td>
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		<tr height="22">
			<td height="22" style="height:22px;width:363px;">Hydrocortisone</td>
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			<td style="width:207px;">H4001</td>
			<td style="width:167px;"></td>
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			<td height="26" style="height:26px;width:363px;">Stem Cell Factor (SCF)</td>
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		</tr>
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			<td height="22" style="height:22px;width:363px;">Interleukin-3 (IL-3)</td>
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			<td style="width:207px;">213-13</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:363px;">EPOGEN Epoetin Alfa (Erythropoietin, EPO)</td>
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			<td height="31" style="height:31px;width:363px;">CD44-FITC antibody</td>
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			<td height="28" style="height:28px;width:363px;">CD71-FITC antibody</td>
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			<td style="width:207px;">553266</td>
			<td style="width:167px;"></td>
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		<tr height="30">
			<td height="30" style="height:30px;width:363px;">Ter119-PECy7 antibody</td>
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		<tr height="24">
			<td height="24" style="height:24px;width:363px;">Phalloidin-AF488</td>
			<td style="width:199px;">Invitrogen (Life Technologies)</td>
			<td style="width:207px;">A12379</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:363px;">&#946;-tubulin-AF488 antibody</td>
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			<td style="width:167px;"></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:363px;">anti-rabbit AF488-secondary antibody</td>
			<td style="width:199px;">Invitrogen (Life Technologies)</td>
			<td style="width:207px;">A11008</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:363px;">anti-rabbit AF555-secondary antibody</td>
			<td style="width:199px;">Invitrogen (Life Technologies)</td>
			<td style="width:207px;">A21428</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:363px;">AF594-cholera toxin B subunit</td>
			<td style="width:199px;">Invitrogen (Life Technologies)</td>
			<td style="width:207px;">C34777</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:363px;">pMRLC (Ser19) antibody</td>
			<td style="width:199px;">Cell Signaling</td>
			<td style="width:207px;">#3671</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:363px;">&#947;-tubulin antibody</td>
			<td style="width:199px;">Sigma</td>
			<td style="width:207px;">T-3559</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:363px;">Syto16</td>
			<td style="width:199px;">Invitrogen (Life Technologies)</td>
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		<tr height="22">
			<td height="22" style="height:22px;width:363px;">Draq5</td>
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			<td style="width:167px;"></td>
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		<tr height="22">
			<td height="22" style="height:22px;width:363px;">Ferrous sulfate</td>
			<td style="width:199px;">Sigma</td>
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			<td style="width:167px;"></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:363px;">Ferric nitrate</td>
			<td style="width:199px;">Sigma</td>
			<td style="width:207px;">F3002</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:363px;">EDTA</td>
			<td style="width:199px;">Fisher Scientific</td>
			<td style="width:207px;">BP120500</td>
			<td style="width:167px;"></td>
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		<tr height="37">
			<td height="37" style="height:37px;width:363px;">15ml tubes</td>
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			<td height="30" style="height:30px;width:363px;">50ml tubes</td>
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		<tr height="31">
			<td height="31" style="height:31px;width:363px;">6-well plates</td>
			<td style="width:199px;">BD Falcon</td>
			<td style="width:207px;">353046</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="27">
			<td height="27" style="height:27px;width:363px;">24-well plates</td>
			<td style="width:199px;">BD Falcon</td>
			<td style="width:207px;">351147</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="31">
			<td height="31" style="height:31px;width:363px;">Flow tubes</td>
			<td style="width:199px;">BD Falcon</td>
			<td style="width:207px;">352008</td>
			<td style="width:167px;"></td>
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		<tr height="22">
			<td height="22" style="height:22px;width:363px;">Tuberculin syringe</td>
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			<td style="width:167px;"></td>
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		<tr height="22">
			<td height="22" style="height:22px;width:363px;">Insulin syringe</td>
			<td style="width:199px;">BD</td>
			<td style="width:207px;">329461</td>
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		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:363px;">Syringe needle 25G5/8</td>
			<td style="width:199px;">BD</td>
			<td style="width:207px;">305122</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:363px;">Capped flow tubes</td>
			<td style="width:199px;">BD</td>
			<td style="width:207px;">352058</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="27">
			<td height="27" style="height:27px;width:363px;">40&#956;m cell strainer</td>
			<td style="width:199px;">BD Falcon</td>
			<td style="width:207px;">352340</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:363px;">Scalpel (disposable)</td>
			<td style="width:199px;">Feather</td>
			<td style="width:207px;">2975#21</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:363px;">FACS Canto Flow Cytometer</td>
			<td style="width:199px;">BD</td>
			<td style="width:207px;"></td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:363px;">ImagestreamX Mark II Imaging Flow Cytometer</td>
			<td style="width:199px;">AMNIS (EMD Millipore)</td>
			<td style="width:207px;"></td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="48">
			<td height="48" style="height:48px;width:363px;">Image Data Exploration and Analysis Software (IDEAS) version 4.0 and up.</td>
			<td style="width:199px;">AMNIS (EMD Millipore)</td>
			<td style="width:207px;"></td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:363px;">Hemavet 950 Cell Counter</td>
			<td style="width:199px;">Drew Scientific</td>
			<td>CDC-9950-002</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">NAPCO series 8000WJ Incubator</td>
			<td style="width:199px;">Thermo scientific</td>
			<td style="width:207px;"></td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">Allegra X-15R Centrifuge</td>
			<td style="width:199px;">Beckman Coulter</td>
			<td>392932</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:363px;">Mini Mouse Bench centrifuge</td>
			<td style="width:199px;">Denville</td>
			<td style="width:207px;">C0801</td>
			<td style="width:167px;"></td>
		</tr>
	</tbody>
</table>

identification of a murine erythroblast subpopulation  enriched in enucleating events by multi-spectral imaging flow cytometry

Erythropoiesis ביונקים מסתיים בתהליך הדרמטי של אנוקלאציה כי תוצאות היווצרות reticulocyte. המנגנון של אנוקלאציה טרם הובהר במלואו. בעיה נפוצה נתקלה כאשר לומדים את הלוקליזציה של חלבונים ומבני מפתח בתוך erythroblasts enucleating ידי מיקרוסקופ היא הקושי לצפות במספר מספק של תאים עוברים אנוקלאציה. פיתחנו פרוטוקול ניתוח חדשני באמצעות הדמיה multiparameter במהירות גבוהה תא בזרימה (Multi-Spectral Imaging cytometry הזרימה), שיטה המשלבת מיקרוסקופיה immunofluorescent עם cytometry זרימה, על מנת לזהות ביעילות מספר משמעותי של אירועי enucleating, המאפשר ל להשיג מדידות וביצוע ניתוחים סטטיסטיים. אנחנו הראשונים מתארים כאן שתי שיטות מבחנה התרבות בerythropoiesis משמשות כדי לסנכרן erythroblasts העכברי ולהגדיל את ההסתברות ללכידת אנוקלאציה בהזמן דואר של הערכה. לאחר מכן, אנו מתארים בפירוט את ההכתמה של erythroblasts לאחר הקיבוע וpermeabilization כדי ללמוד את הלוקליזציה של חלבונים תאיים או רפסודות שומנים בדם במהלך אנוקלאציה ידי זרימת הדמיה רבת רפאים cytometry. יחד עם גודל ומכתים DNA/Ter119 אשר משמשים כדי לזהות את erythroblasts אורתוכרומטי, אנו מנצלים את הפרמטרים &quot;יחס&quot; של תא בערוץ הבהיר השדה שמסייע בזיהוי של תאים מוארכים ו&quot; centroid דלתא XY Ter119/Draq5 &quot;המאפשר זיהוי של אירועים הסלולר שבמרכז מכתים Ter119 (reticulocyte המתהווה) הוא רחוק אחד מהשני מהמרכז מכתים Draq5 (שיחול גרעין עובר), ובכך מצביע על תא עומד enucleate. קבוצת המשנה של אוכלוסיית erythroblast אורתוכרומטי עם centroid דלתא גבוה ויחס נמוך מועשר בenucleating תאים.

ראשית, תאים מנותחים על בסיס יחס הממדים Brightfield (היחס בין אורכם הקטינים לעומת הציר המרכזי שלהם) ופינת Brightfield (מעיד על הגודל שלהם). אירועים עם ערך פינת Brightfield נמוך מ20 וגבוהים יותר מאשר 200 הם בעיקר אגרגטים פסולת ותאים, בהתאמה, והם נכללים בניתוח (איור 2 א). תאים בודדים (...

Watch this Scientific Journal Video about Identification of a Murine Erythroblast Subpopulation  Enriched in Enucleating Events by Multi-spectral Imaging Flow Cytometry at JoVE.com

Identification of a Murine Erythroblast Subpopulation  Enriched in Enucleating Events by Multi-spectral Imaging Flow Cytometry

הפרוטוקול הנוכחי מתאר שיטה חדשה לזיהוי אוכלוסייה של enucleating erythroblasts אורתוכרומטי ידי זרימת הדמיה רבת רפאים cytometry, מתן להדמיה של תהליך אנוקלאציה erythroblast.

זיהוי של subpopulation מועשר Murine Erythroblast באירועי Enucleating ידי Multi-רפאים הדמיה תזרים cytometry

Erythropoiesis in mammals concludes with the dramatic process of enucleation that results in reticulocyte formation. The mechanism of enucleation has not ...

identification-murine-erythroblast-subpopulation-enriched-enucleating

Research

JoVE Journal

Biology

12.5K Views.  University of Cincinnati College of Medicine.  הפרוטוקול הנוכחי מתאר שיטה חדשה לזיהוי אוכלוסייה של enucleating erythroblasts אורתוכרומטי ידי זרימת הדמיה רבת רפאים cytometry, מתן להדמיה של תהליך אנוקלאציה erythroblast. 

Video: Identification of a Murine Erythroblast Subpopulation  Enriched in Enucleating Events by Multi-spectral Imaging Flow Cytometry

IP-FCM:  Immunoprecipitation Detected by Flow Cytometry

Immunoprecipitation detected by flow cytometry (IP-FCM) is an efficient method for detecting and quantifying protein-protein interactions. The basic principle extends that of sandwich ELISA, wherein the captured primary analyte can be detected together with other molecules physically associated within multiprotein complexes. The procedure involves covalent coupling of polystyrene latex microbeads with immunoprecipitating monoclonal antibodies (mAb) specific for a protein of interest, incubating these beads with cell lysates, probing captured protein complexes with fluorochrome-conjugated probes, and analyzing bead-associated fluorescence by flow cytometry. IP-FCM is extremely sensitive, allows analysis of proteins in their native (non-denatured) state, and is amenable to either semi-quantitative or quantitative analysis. As additional advantages, IP-FCM requires no genetic engineering or specialized equipment, other than a flow cytometer, and it can be readily adapted for high-throughput applications.

The IP-FCM method is presented, which allows a sensitive, robust, biochemical assessment of native protein-protein interactions, without requiring genetic engineering or large sample sizes.

IP-FCM: immunoprecipitation זוהה על ידי זרימת cytometry

Immunoprecipitation detected by flow cytometry (IP-FCM) is an efficient method for detecting and quantifying protein-protein interactions. The basic ...

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.

Cytometry זרימה טיהור תאים עכבר meiotic

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 ...

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.

אופטימיזציה שיטות דוגמנות מכתימה והפצת נשק לניטור חלוקת תא באמצעות צבעי מעקב סלולרי

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

Live Cell Imaging of Early Autophagy Events: Omegasomes and Beyond

Autophagy is a cellular response triggered by the lack of nutrients, especially the absence of amino acids. Autophagy is defined by the formation of double membrane structures, called autophagosomes, that sequester cytoplasm, long-lived proteins and protein aggregates, defective organelles, and even viruses or bacteria. Autophagosomes eventually fuse with lysosomes leading to bulk degradation of their content, with the produced nutrients being recycled back to the cytoplasm. Therefore, autophagy is crucial for cell homeostasis, and dysregulation of autophagy can lead to disease, most notably neurodegeneration, ageing and cancer.	
	Autophagosome formation is a very elaborate process, for which cells have allocated a specific group of proteins, called the core autophagy machinery. The core autophagy machinery is functionally complemented by additional proteins involved in diverse cellular processes, e.g. in membrane trafficking, in mitochondrial and lysosomal biology. Coordination of these proteins for the formation and degradation of autophagosomes constitutes the highly dynamic and sophisticated response of autophagy. Live cell imaging allows one to follow the molecular contribution of each autophagy-related protein down to the level of a single autophagosome formation event and in real time, therefore this technique offers a high temporal and spatial resolution.	
	Here we use a cell line stably expressing GFP-DFCP1, to establish a spatial and temporal context for our analysis. DFCP1 marks omegasomes, which are precursor structures leading to autophagosomes formation. A protein of interest (POI) can be marked with either a red or cyan fluorescent tag. Different organelles, like the ER, mitochondria and lysosomes, are all involved in different steps of autophagosome formation, and can be marked using a specific tracker dye. Time-lapse microscopy of autophagy in this experimental set up, allows information to be extracted about the fourth dimension, i.e. time. Hence we can follow the contribution of the POI to autophagy in space and time.

Time-lapse microscopy of fluorescently labeled autophagy markers allows monitoring of the dynamic autophagy response with high temporal resolution. Using specific autophagy and organelle markers in a combination of 3 different colors, we can follow the contribution of a protein to autophagosome formation in a robust spatial and temporal context.

לחיות תא הדמיה של אירועי autophagy מוקדמים: Omegasomes ומעבר

Autophagy is a  cellular response triggered by the lack of nutrients, especially the absence of  amino acids. Autophagy is defined by the formation of ...

In Vivo 4-Dimensional Tracking of Hematopoietic Stem and Progenitor Cells in Adult Mouse Calvarial Bone Marrow

Through a delicate balance between quiescence and proliferation, self renewal and production of differentiated progeny, hematopoietic stem cells (HSCs) maintain the turnover of all mature blood cell lineages. The coordination of the complex signals leading to specific HSC fates relies upon the interaction between HSCs and the intricate bone marrow microenvironment, which is still poorly understood[1-2].
We describe how by combining a newly developed specimen holder for stable animal positioning with multi-step confocal and two-photon in vivo imaging techniques, it is possible to obtain high-resolution 3D stacks containing HSPCs and their surrounding niches and to monitor them over time through multi-point time-lapse imaging. High definition imaging allows detecting ex vivo labeled hematopoietic stem and progenitor cells (HSPCs) residing within the bone marrow. Moreover, multi-point time-lapse 3D imaging, obtained with faster acquisition settings, provides accurate information about HSPC movement and the reciprocal interactions between HSPCs and stroma cells.
Tracking of HSPCs in relation to GFP positive osteoblastic cells is shown as an exemplary application of this method. This technique can be utilized to track any appropriately labeled hematopoietic or stromal cell of interest within the mouse calvarium bone marrow space.

In Vivo 4-Dimensional Tracking of Hematopoietic Stem and Progenitor Cells in Adult Mouse Calvarial Bone Marrow

The nature of the interactions between hematopoietic stem and progenitor cells (HSPCs) and bone marrow niches is poorly understood. Custom hardware modifications and a multi-step acquisition protocol allow the use of two-photon and confocal microscopy to image ex vivo labeled HSPCs homed within bone marrow areas, tracking interactions and movement.

במעקב 4 ממדי Vivo של תאי גזע ואבות היווצרות דם במבוגרי עכבר calvarial מח עצם

Through a delicate balance between quiescence and proliferation, self renewal and production of differentiated progeny, hematopoietic stem cells (HSCs) ...

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.

מדידות סידן cytosolic בתאי האפיתל כליות על ידי cytometry הזרימה

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

Identification of Intracellular Signaling Events Induced in Viable Cells by Interaction with Neighboring Cells Undergoing Apoptotic Cell Death

Cells dying by apoptosis, also referred to as regulated cell death, acquire multiple new activities that enable them to influence the function of adjacent live cells. Vital activities, such as survival, proliferation, growth, and differentiation, are among the many cellular functions modulated by apoptotic cells. The ability to recognize and respond to apoptotic cells appears to be a universal feature of all cells, regardless of lineage or organ of origination. However, the diversity and complexity of the response to apoptotic cells mandates that great care be taken in dissecting the signaling events and pathways responsible for any particular outcome. In particular, one must distinguish among the multiple mechanisms by which apoptotic cells can influence intracellular signaling pathways within viable responder cells, including: receptor-mediated recognition of the apoptotic cell, release of soluble mediators by the apoptotic cell, and/or engagement of the phagocytic machinery. Here, we provide a protocol for identifying intracellular signaling events that are induced in viable responder cells following their exposure to apoptotic cells. A major advantage of the protocol lies in the attention it pays to dissection of the mechanism by which apoptotic cells modulate signaling events within responding cells. While the protocol is specific for a conditionally immortalized mouse kidney proximal tubular cell line (BU.MPT cells), it is easily adapted to cell lines that are non-epithelial in origin and/or derived from organs other than the kidney. The use of dead cells as a stimulus introduces several unique factors that can hinder the detection of intracellular signaling events. These problems, as well as strategies to minimize or circumvent them, are discussed within the protocol. Application of this protocol should aid our expanding knowledge of the broad influence that dead or dying cells exert on their live neighbors, both in health and in disease.

Here, we present a protocol for the determination of intracellular signaling events induced in viable cells by physical interaction with adjacent dead or dying cells. The protocol focuses on signaling events induced by receptor-mediated recognition of the dead cells, as opposed to their phagocytic uptake or release of soluble mediators.

זיהוי של איתות תאיים אירועים מושרה תאים קיימא על ידי אינטראקציה עם תאים שכנים מוות של תאים אפופטוטיים שעברו

Cells dying by apoptosis, also referred to as regulated cell death, acquire multiple new activities that enable them to influence the function of adjacent ...

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.

ניתוח של המתלים תא מבודד מרקמות Solid ידי זרימת cytometry ספקטרלי

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 ...

Measuring Endoreduplication by Flow Cytometry of Isolated Tuber Protoplasts

Endoreduplication, the replication of a cell's nuclear genome without subsequent cytokinesis, yields cells with increased DNA content and is associated with specialization, development and increase in cellular size. In plants, endoreduplication seems to facilitate the growth and expansion of certain tissues and organs. Among them is the tuber of potato (Solanum tuberosum), which undergoes considerable cellular expansion in fulfilling its function of carbohydrate storage. Thus, endoreduplication may play an important role in how tubers are able to accommodate this abundance of carbon. However, the cellular debris resulting from crude nuclear isolation methods of tubers, methods that can be used effectively with leaves, precludes the estimation of the tuber endoreduplication index (EI). This article presents a technique for assessing tuber endoreduplication through the isolation of protoplasts while demonstrating representative results obtained from different genotypes and compartmentalized tuber tissues. The major limitations of the protocol are the time and reagent costs required for sample preparation as well as relatively short lifespan of samples after lysis of protoplasts. While the protocol is sensitive to technical variation, it represents an improvement over traditional methods of nuclear isolation from these large specialized cells. Possibilities for improvements to the protocol such as recycling enzyme, the use of fixatives, and other alterations are proposed.

The protocol described herein is a method for measuring endoreduplication within tubers of potato (Solanum tuberosum). It includes plasmolysis and protoplast extraction steps to decrease the noise and debris in downstream flow cytometric analysis.

מדידת Endoreduplication על ידי Cytometry זרימה של פקעת מבודד Protoplasts

Endoreduplication, the replication of a cell's nuclear genome without subsequent cytokinesis, yields cells with increased DNA content and is associated ...

Sensitive Measurement of Mitophagy by Flow Cytometry Using the pH-dependent Fluorescent Reporter mt-Keima

Mitophagy is a process of selective removal of damaged or unnecessary mitochondria using autophagy machinery. Close links have been found between defective mitophagy and various human diseases, including neurodegenerative diseases, cancer, and metabolic diseases. In addition, recent studies have shown that mitophagy is involved in normal cellular processes, such as differentiation and development. However, the precise role of and molecular mechanisms underlying mitophagy require further study. Therefore, it is critical to develop a robust and convenient method for measuring changes in mitophagy activity. Here, we describe a detailed protocol for quantitatively assessing mitophagy activity through flow cytometry using the mitochondria-targeted fluorescent protein Keima (mt-Keima). This flow cytometry assay can analyze mitophagy activity more rapidly and sensitively than conventional microscopy- or immunoblotting-based methods. This protocol can be applied to analyze mitophagy activity in various cell types.

Mitophagy, the selective degradation of mitochondria, has been implicated in mitochondrial homeostasis and is deregulated in various human diseases. However, convenient experimental methods for measuring mitophagy activity are very limited. Here, we provide a sensitive assay for measuring mitophagy activity using flow cytometry.