Les auteurs tiennent à remercier le Dr Klaus Kaestner pour le don du murin Ngn3-EGFP ligne de cellules souches embryonnaires, Mme Lucy Brown et le Core cytométrie analytique de l&#39;aide pour le tri cellulaire. Ce travail a été financé en partie par des subventions du NIH et de R21DK069997 R01DK081587 décerné à HTK et de California Institute for Regenerative Medicine (CIRM) bourses de formation accordées aux MW et LS

<ol>
	<li>Ku, H. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Committing+embryonic+stem+cells+to+early+endocrine+pancreas+in+vitro.">Committing embryonic stem cells to early endocrine pancreas in vitro.</a> Stem cells. 22, 1205-1217 (2004).</li><li>Ku, H. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Insulin-expressing+colonies+developed+from+murine+embryonic+stem+cell-derived+progenitors.">Insulin-expressing colonies developed from murine embryonic stem cell-derived progenitors.</a> Diabetes. 56, 921-929 (2007).</li><li>Chen, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+an+in+vitro+differentiation+assay+for+pancreatic-like+cell+development+from+murine+embryonic+stem+cells:+detailed+gene+expression+analysis.">Characterization of an in vitro differentiation assay for pancreatic-like cell development from murine embryonic stem cells: detailed gene expression analysis.</a> Assay. Drug. Dev. Technol. 9, 403-419 (2011).</li><li>Lee, C. S., Perreault, N., Brestelli, J. E., Kaestner, K. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neurogenin+3+is+essential+for+the+proper+specification+of+gastric+enteroendocrine+cells+and+the+maintenance+of+gastric+epithelial+cell+identity.">Neurogenin 3 is essential for the proper specification of gastric enteroendocrine cells and the maintenance of gastric epithelial cell identity.</a> Genes. 16, 1488-1497 (2002).</li><li>Gu, G., Dubauskaite, J., Melton, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct+evidence+for+the+pancreatic+lineage:+NGN3++cells+are+islet+progenitors+and+are+distinct+from+duct+progenitors.">Direct evidence for the pancreatic lineage: NGN3+ cells are islet progenitors and are distinct from duct progenitors.</a> Development. 129, 2447-2457 (2002).</li><li>Ogawa, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differentiation+and+proliferation+of+hematopoietic+stem+cells.">Differentiation and proliferation of hematopoietic stem cells.</a> Blood. 81, 2844-2853 (1993).</li><li>Gittes, G. K., Galante, P. E., Hanahan, D., Rutter, W. J., Debase, H. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lineage-specific+morphogenesis+in+the+developing+pancreas:+role+of+mesenchymal+factors.">Lineage-specific morphogenesis in the developing pancreas: role of mesenchymal factors.</a> Development. 122, 439-447 (1996).</li><li>Miralles, F., Battelino, T., Czernichow, P., Scharfmann, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=TGF-beta+plays+a+key+role+in+morphogenesis+of+the+pancreatic+islets+of+Langerhans+by+controlling+the+activity+of+the+matrix+metalloproteinase+MMP-2.">TGF-beta plays a key role in morphogenesis of the pancreatic islets of Langerhans by controlling the activity of the matrix metalloproteinase MMP-2.</a> J. Cell. Biol. 143, 827-836 (1998).</li><li>Bonner-Weir, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+cultivation+of+human+islets+from+expanded+ductal+tissue.">In vitro cultivation of human islets from expanded ductal tissue.</a> Proc. Natl. Acad. Sci. U. S. A. 97, 7999-8004 (2000).</li><li>Gao, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+endocrine+progenitor+cells+and+critical+factors+for+their+differentiation+in+human+adult+pancreatic+cell+culture.">Characterization of endocrine progenitor cells and critical factors for their differentiation in human adult pancreatic cell culture.</a> Diabetes. 52, 2007-2015 (2003).</li><li>Gao, R., Ustinov, J., Korsgren, O., Otonkoski, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+neogenesis+of+human+islets+reflects+the+plasticity+of+differentiated+human+pancreatic+cells.">In vitro neogenesis of human islets reflects the plasticity of differentiated human pancreatic cells.</a> Diabetologia. 48, 2296-2304 (2005).</li><li>Suarez-Pinzon, W. L., Lakey, J. R., Brand, S. J., Rabinovitch, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combination+therapy+with+epidermal+growth+factor+and+gastrin+induces+neogenesis+of+human+islet+beta-cells+from+pancreatic+duct+cells+and+an+increase+in+functional+beta-cell+mass.">Combination therapy with epidermal growth factor and gastrin induces neogenesis of human islet beta-cells from pancreatic duct cells and an increase in functional beta-cell mass.</a> J. Clin. Endocrinol. Metab. 90, 3401-3409 (2005).</li><li>Hao, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Beta-cell+differentiation+from+nonendocrine+epithelial+cells+of+the+adult+human+pancreas.">Beta-cell differentiation from nonendocrine epithelial cells of the adult human pancreas.</a> Nature Medicine. 12, 310-316 (2006).</li><li>Ku, H. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Minireview:+pancreatic+progenitor+cells--recent+studies.">Minireview: pancreatic progenitor cells--recent studies.</a> Endocrinology. 149, 4312-4316 (2008).</li><li>Seaberg, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clonal+identification+of+multipotent+precursors+from+adult+mouse+pancreas+that+generate+neural+and+pancreatic+lineages.">Clonal identification of multipotent precursors from adult mouse pancreas that generate neural and pancreatic lineages.</a> Nature Biotechnology. 22, 1115-1124 (2004).</li><li>Rovira, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+and+characterization+of+centroacinar/terminal+ductal+progenitor+cells+in+adult+mouse+pancreas.">Isolation and characterization of centroacinar/terminal ductal progenitor cells in adult mouse pancreas.</a> Proc. Natl. Acad. Sci. U. S. A. 107, 75-80 (2010).</li></ol>

Nous n&#39;avons rien à révéler.

Colony dosages qui permettent des évaluations quantitatives et fonctionnelles des progéniteurs pancréatiques individuels ont été limités jusqu&#39;ici, ce qui a grandement entravé les progrès dans les études des souches pancréatiques et la biologie de cellules progénitrices. L&#39;essence d&#39;un dosage de la colonie, c&#39;est qu&#39;il mesure la capacité intrinsèque des cellules progénitrices, plutôt qu&#39;uniquement de leur phénotype, permettant à la fonctionnalité et le potentiel lignée des cellules progénitrices d&#39;être observé. Il est également un outil quantitatif qui peut déterminer le nombre de progéniteurs dans une population donnée. Dans le domaine des cellules souches hématopoïétiques, des dosages colonie ont joué un rôle important dans l&#39;identification, ainsi que déchiffrer les exigences du facteur de croissance, des interactions et des mécanismes régissant l&#39;engagement de la lignée de ces cellules. 6 Dans le domaine de la biologie des cellules pancréatiques progénitrices, 7 organes du pancréas , 8 ou 9 à 13 en vrac cultures ont été imaginés, toutefois, de tels dosages biologiques ne traitent pas questions au niveau de la cellule unique. Sans analyses cellule unique, l&#39;existence de souches pancréatiques multi-potentiels / progéniteurs ne peut être prouvé sans équivoque 14. Ici, nous montrons que l&#39;insuline exprimant formant colonie progéniteurs peuvent être analysés en utilisant un modèle tridimensionnel, Matrigel contenant, système de culture semi-solide. Bien qu&#39;un système de culture en suspension 15,16 a été développé qui permet seule progéniteurs pancréatiques adultes à proliférer et se différencier en &quot;pancreatospheres&quot;, notre test colonie offre des avantages supplémentaires. Premièrement, notre semi-solide culture médiatique système permet le placage de jusqu&#39;à 25.000 cellules triées par 500 ul par les milieux de culture de 24 puits tout en maintenant la formation de colonies résultant de la gamme linéaire. 2 En revanche, le dosage pancreatosphere suspension nécessite l&#39;utilisation d&#39;une seule méthode de dépôt de cellules de la trieuse de cellules pour permettre des analyses cellule unique, et donc un volume plus important de la culture médiatique et de l&#39;espace incubateursont nécessaires. Par conséquent, notre analyse colonie est relativement facile et rentable d&#39;effectuer lorsqu&#39;un grand nombre de cellules différentes doivent être comparées simultanément à des activités progénitrices. Deuxièmement, notre semi-solide de médias permet une distribution uniforme des composants de la matrice extracellulaire et les facteurs de croissance, ce qui permet à la fois la prolifération et de différenciation de se produire dans le même puits. En revanche, il est plus difficile de fournir un tel environnement, en particulier la matrice, à des cellules en culture en suspension. Nous sommes conscients que notre méthode ne peut pas être définitivement prouvé que chaque colonie est dérivé d&#39;une seule cellule, comme deux progéniteurs peuvent être positionnés au hasard près de l&#39;autre et forment une colonie. Toutefois, ce problème peut être surmonté par une analyse secondaire en utilisant la manipulation seule cellule. Direct cueillette manuelle des cellules triées unique pourrait définitivement démontrer l&#39;origine cellule unique de chaque colonie. En résumé, l&#39;insuline exprimant formant colonie activité de progéniteurs dans les milieux semi-solides décrite ici fournit des occasions uniques pour des études mécanistiques des progéniteurs pancréatiques au niveau cellulaire unique. Par exemple, dans un rapport antérieur, nous avons trouvé que l&#39;ajout de Matrigel, un mélange brut de protéines de la matrice extracellulaire, dans la culture des médias est nécessaire pour la formation de l&#39;insuline par les cellules exprimant colonies + Ngn3-EGFP, 2 suggérant la matrice extracellulaire est important pour ceux progéniteurs. L&#39;utilisation de ce test colonie, il sera désormais possible de disséquer et de définir les exigences spécifiques de matrice pour une telle activité. En plus d&#39;étudier les progéniteurs des cellules dérivées de souches embryonnaires de souris, nous étudions actuellement si ce système de test in vitro soutient également la formation d&#39;autres colonies distinctes provenant du pancréas et du foie de souris en périnatalité et pour adultes, ainsi que du tissu pancréatique humain cadavérique dénuée d&#39;îlots.

<table border="1"><tbody><tr><td> Matériel / Réactif </td><td> Société </td><td> Catalogue Nombre </td><td> Commentaires </td></tr><tr><td> 1X DMEM / F-12 (01:01) </td><td> Mediatech </td><td> 15 à 090-CV </td><td></td></tr><tr><td> Sérum de veau foetal </td><td> Tissue Culture Biologicals </td><td> 201 </td><td> Se reporter à la section 1.1 </td></tr><tr><td> L-glutamine </td><td> Gibco </td><td> 25030-081 </td><td></td></tr><tr><td> 1X PBS Dulbecco </td><td> Mediatech </td><td> 21 à 031-CV </td><td></td></tr><tr><td> De sérum bovin Albumine </td><td> Sigma </td><td> A8412 </td><td> 7,5% </td></tr><tr><td> Matrigel </td><td> Becton Dickinson </td><td> 356231 </td><td> Croissance réduite Facteur </td></tr><tr><td> Méthylcellulose </td><td> Sinetsu Chimique, Tokyo, Japon </td><td></td><td> 1500 centipoises (Haute viscosity) </td></tr><tr><td> Nicotinamide </td><td> Sigma </td><td> N0636 </td><td></td></tr><tr><td> Homme Recombinant Activine ßB </td><td> R &amp; D Systems </td><td> 659-AB-025 </td><td></td></tr><tr><td> Exendin-4 </td><td> Sigma </td><td> E7144 </td><td></td></tr><tr><td> Homme Recombinant Le VEGF-A </td><td> R &amp; D Systems </td><td> 293-VE-010 </td><td></td></tr><tr><td> Plaques à 24 puits </td><td> Costar </td><td> 3473 </td><td> Ultra-faible Pièce jointe </td></tr><tr><td> 60mm boîte de Pétri avec grille </td><td> Nunc </td><td> 169558 </td><td></td></tr></tbody></table>

a quantitative assay for insulin-expressing colony-forming progenitors

Le domaine de souches pancréatiques et la biologie de cellules progénitrices ont été entravés par un manque d&#39;essais in vitro fonctionnelles et quantitatives qui permettent l&#39;analyse de la cellule unique. Analyses des progéniteurs simples sont d&#39;une importance cruciale car elles fournissent des moyens définitive à démontrer sans équivoque le potentiel lignée des progéniteurs individuels. Bien que les méthodes ont été conçues pour générer des «pancreatospheres&quot; en culture en suspension de cellules uniques, plusieurs limitations existent. Premièrement, il est temps pour réaliser le dépôt cellule unique pour un grand nombre de cellules qui, à son tour les commandes de gros volumes de milieux de culture et de l&#39;espace. Deuxièmement, la numération de l&#39;pancreatospheres qui en résulte est une main-d&#39;œuvre, surtout lorsque la fréquence des progéniteurs pancreatosphere-initiation est faible. Troisièmement, le dosage pancreatosphere n&#39;est pas une méthode efficace pour permettre à la fois la prolifération et la différenciation des progéniteurs du pancréas dans la même culture et, à nouveaustricting l&#39;utilité du dosage. Pour surmonter ces limitations, un dosage de milieux semi-solides pour la colonie basée progéniteurs pancréatiques a été élaboré et est présentée dans ce rapport. Cette méthode tire parti d&#39;un concept existant à partir du dosage de colonies hématopoïétiques, dans lequel la méthylcellulose est utilisé pour fournir viscosité pour les médias, permettant les cellules progénitrices de rester dans un espace tridimensionnel car ils subissent la prolifération ainsi que la différenciation. Pour enrichir l&#39;insuline exprimant formant colonie progéniteurs d&#39;une population hétérogène, nous avons utilisé les cellules qui expriment Neurogenin (NGN) 3, un pancréas endocrine de cellules progénitrices marqueur. Murin souches embryonnaires (ES) dérivés de cellules Ngn3 cellules exprimant taggés avec le journaliste améliorée protéine fluorescente verte ont été triés et autant que 25 000 cellules par puits ont été étalées dans peu d&#39;attachement des boîtes de culture de 24 puits. Chaque puits contenait 500 ul de milieux semi-solides avec les principaux éléments suivants: a rencontréhylcellulose, Matrigel, la nicotinamide, Exendin-4, activine ßB, et des milieux conditionnés provenant murines ES dérivées de cellules pancréatiques, comme des cellules. Après 8 à 12 jours de culture, de l&#39;insuline exprimant colonies ayant une morphologie distinctive ont été formés et pourrait encore être analysés pour l&#39;expression des gènes du pancréas en utilisant RT-PCR quantitative et coloration immunoflourescent pour déterminer la composition lignée de chaque colonie. En résumé, notre analyse permet de détecter facilement la colonie et la quantification des progéniteurs fonctionnelle au sein d&#39;une population hétérogène de cellules. En outre, le format de milieux semi-solides permet une présentation uniforme des composants de la matrice extracellulaire et les facteurs de croissance pour les cellules, permettant progéniteurs à proliférer et à se différencier in vitro. Ce test fournit la colonie des opportunités uniques pour des études mécanistiques des cellules progénitrices du pancréas au niveau de la cellule unique.

Watch this Scientific Journal Video about A Quantitative Assay for Insulin-expressing Colony-forming Progenitors at JoVE.com

A Quantitative Assay for Insulin-expressing Colony-forming Progenitors

Un test en trois dimensions qui permet clonogénique pancréatique comme géniteurs à se différencier en insuline exprimer colonies est décrite. Cette méthode tire parti des milieux semi-solides contenant des facteurs de la méthylcellulose, Matrigel et la croissance, dans lequel seule progéniteurs prolifèrent et se différencient<em&gt; In vitro</em&gt;, Qui permet la quantification du nombre de progéniteurs fonctionnelle dans une population.

Un dosage quantitatif de l&#39;insuline exprimer formant colonie Progéniteurs

The field of pancreatic stem and progenitor cell biology has been hampered by a lack of in vitro functional and quantitative assays that allow for the ...

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13.4K vues.  California State University Channel Islands. Un test en trois dimensions qui permet clonogénique pancréatique comme géniteurs à se différencier en insuline exprimer colonies est décrite. Cette méthode tire parti des milieux semi-solides contenant des facteurs de la méthylcellulose, Matrigel et la croissance, dans lequel seule progéniteurs prolifèrent et se différencient In vitro, Qui permet la quantification du nombre de progéniteurs fonctionnelle dans une population.

Vidéo: A Quantitative Assay for Insulin-expressing Colony-forming Progenitors

Quantitative Phosphoproteomics in Fatty Acid Stimulated Saccharomyces cerevisiae

This protocol describes the growth and stimulation, with the fatty acid oleate, of isotopically heavy and light S. cerevisiae cells. Cells are ground using a cryolysis procedure in a ball mill grinder and the resulting grindate brought into solution by urea solubilization. This procedure allows for the lysis of the cells in a metabolically inactive state, preserving phosphorylation and preventing reorientation of the phosphoproteome during cell lysis.  Following reduction, alkylation, trypsin digestion of the proteins, the samples are desalted on C18 columns and the sample complexity reduced by fractionation using hydrophilic interaction chromatography (HILIC). HILIC columns preferentially retain hydrophilic molecules which is well suited for phosphoproteomics.  Phosphorylated peptides tend to elute later in the chromatographic profile than the non phosphorylated counterparts. After fractionation, phosphopeptides are enriched using immobilized metal chromatography, which relies on charge-based affinities for phosphopeptide enrichment. At the end of this procedure the samples are ready to be quantitatively analyzed by mass spectrometry.

Quantitative Phosphoproteomics in Fatty Acid Stimulated Saccharomyces cerevisiae

Description of a quantitative phosphorylation procedure using cryolysis, urea solubilziation, HILIC fractionation and IMAC enrichment of phosphorylated peptides.

Phosphoprotéomique quantitatives en acide gras Stimulé Saccharomyces cerevisiae</em

This protocol describes the growth and stimulation, with the fatty acid oleate, of isotopically heavy and light S. cerevisiae cells. Cells are ground ...

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Biologie

Isolation and Large Scale Expansion of Adult Human Endothelial Colony Forming Progenitor Cells

This paper introduces a novel recovery strategy for endothelial colony forming progenitor cells (ECFCs) from heparinized but otherwise unmanipulated adult human peripheral blood within a mean of 12 days. After large scale expansion &gt;1x108 ECFCs can be obtained for further tests. Advantageously by using pHPL the contact of human cells with bovine serum antigens can be excluded. By flow cytometry and immunohistochemistry the isolated cells can be characterized as ECFC and their in vitro functionality to form vascular like structures can be tested in a matrigel assay. Further these cells can be subcutaneously injected in a mouse model to form functional, perfused vessels in vivo. After long term expansion and cryopreservation proliferation, function and genomic stability appear to be preserved. 3,4
This animal-protein free isolation and expansion method is easily applicable to generate a large quantity of ECFCs.

Endothelial colony forming progenitor cells (ECFCs) are a promising tool to study vascular homeostasis and repair.1,2 This paper introduces a novel animal-serum free method for isolation and expansion of ECFC from heparinised adult human peripheral blood with pooled human platelet lysate (pHPL) diminishing the risk of anti-bovine immunisation.

L&#39;isolement et expansion à grande échelle des cellules adultes humaines Colony Forming progénitrices endothéliales

This paper introduces a novel recovery strategy for endothelial colony forming progenitor cells (ECFCs) from heparinized but otherwise unmanipulated adult ...

Isolation and Animal Serum Free Expansion of Human Umbilical Cord Derived Mesenchymal Stromal Cells (MSCs) and Endothelial Colony Forming Progenitor Cells (ECFCs)

The umbilical cord is a rich source for progenitor cells with high proliferative potential including mesenchymal stromal cells (also termed mesenchymal stem cells, MSCs) and endothelial colony forming progenitor cells (ECFCs). Both cell types are key players in maintaining the integrity of tissue and are probably also involved in regenerative processes and tumor formation.
To study their biology and function in a comparative manner it is important to have both cells types available from the same donor. It may also be beneficial for regenerative purposes to derive MSCs and ECFCs from the same tissue.
Because cellular therapeutics should eventually find their way from bench to bedside we established a new method to isolate and further expand progenitor cells without the use of animal protein. Pooled human platelet lysate (pHPL) replaced fetal bovine serum in all steps of our protocol to completely avoid contact of the cells to xenogeneic proteins.
This video demonstrates a methodology for the isolation and expansion of progenitor cells from one umbilical cord.
All materials and procedures will be described.

Isolation and Animal Serum Free Expansion of Human Umbilical Cord Derived Mesenchymal Stromal Cells MSCs and Endothelial Colony Forming Progenitor Cells ECFCs

This protocol describes the isolation and subsequent expansion of mesenchymal stromal cells and endothelial colony forming cells without the use of animal serum to generate autologous pairs for experimental transplantation purposes.

Isolement et animale expansion sans sérum du cordon ombilical humain dérivé cellules stromales mésenchymateuses (CSM) et des cellules endothéliales progénitrices Colony Forming (CPEF)

The umbilical cord is a rich source for progenitor cells with high proliferative potential including mesenchymal stromal cells (also termed mesenchymal ...

Identification and Analysis of Mouse Erythroid Progenitors using the CD71/TER119 Flow-cytometric Assay

The study of erythropoiesis aims to understand how red cells are formed from earlier hematopoietic and erythroid progenitors. Specifically, the rate of red cell formation is regulated by the hormone erythropoietin (Epo), whose synthesis is triggered by tissue hypoxia. A threat to adequate tissue oxygenation results in a rapid increase in Epo, driving an increase in erythropoietic rate, a process known as the erythropoietic stress response. The resulting increase in the number of circulating red cells improves tissue oxygen delivery. An efficient erythropoietic stress response is therefore critical to the survival and recovery from physiological and pathological conditions such as high altitude, anemia, hemorrhage, chemotherapy or stem cell transplantation. 
The mouse is a key model for the study of erythropoiesis and its stress response. Mouse definitive (adult-type) erythropoiesis takes place in the fetal liver between embryonic days 12.5 and 15.5, in the neonatal spleen, and in adult spleen and bone marrow. Classical methods of identifying erythroid progenitors in tissue rely on the ability of these cells to give rise to red cell colonies when plated in Epo-containing semi-solid media. Their erythroid precursor progeny are identified based on morphological criteria. Neither of these classical methods allow access to large numbers of differentiation-stage-specific erythroid cells for molecular study. Here we present a flow-cytometric method of identifying and studying differentiation-stage-specific erythroid progenitors and precursors, directly in the context of freshly isolated mouse tissue. The assay relies on the cell-surface markers CD71, Ter119, and on the flow-cytometric 'forward-scatter' parameter, which is a function of cell size. The CD71/Ter119 assay can be used to study erythroid progenitors during their response to erythropoietic stress in vivo, for example, in anemic mice or mice housed in low oxygen conditions. It may also be used to study erythroid progenitors directly in the tissues of genetically modified adult mice or embryos, in order to assess the specific role of the modified molecular pathway in erythropoiesis.

A flow-cytometric method for identification and molecular analysis of differentiation-stage-specific murine erythroid progenitors and precursors, directly in freshly &#x2013;harvested mouse bone marrow, spleen or fetal liver. The assay relies on cell-surface markers CD71, Ter119, and cell size.

Identification et analyse des progéniteurs érythroïdes de la souris en utilisant les CD71/TER119 cytométrie en flux Assay

The study of erythropoiesis aims to understand how red cells are formed from earlier hematopoietic and erythroid progenitors. Specifically, the rate of ...

Phenotypic and Functional Characterization of Endothelial Colony Forming Cells Derived from Human Umbilical Cord Blood

Longstanding views of new blood vessel formation via angiogenesis, vasculogenesis, and arteriogenesis have been recently reviewed1. The presence of circulating endothelial progenitor cells (EPCs) were first identified in adult human peripheral blood by Asahara et al. in 1997 2 bringing an infusion of new hypotheses and strategies for vascular regeneration and repair. EPCs are rare but normal components of circulating blood that home to sites of blood vessel formation or vascular remodeling, and facilitate either postnatal vasculogenesis, angiogenesis, or arteriogenesis largely via paracrine stimulation of existing vessel wall derived cells3. No specific marker to identify an EPC has been identified, and at present the state of the field is to understand that numerous cell types including proangiogenic hematopoietic stem and progenitor cells, circulating angiogenic cells, Tie2+ monocytes, myeloid progenitor cells, tumor associated macrophages, and M2 activated macrophages participate in stimulating the angiogenic process in a variety of preclinical animal model systems and in human subjects in numerous disease states4, 5. Endothelial colony forming cells (ECFCs) are rare circulating viable endothelial cells characterized by robust clonal proliferative potential, secondary and tertiary colony forming ability upon replating, and ability to form intrinsic in vivo vessels upon transplantation into immunodeficient mice6-8. While ECFCs have been successfully isolated from the peripheral blood of healthy adult subjects, umbilical cord blood (CB) of healthy newborn infants, and vessel wall of numerous human arterial and venous vessels 6-9, CB possesses the highest frequency of ECFCs7 that display the most robust clonal proliferative potential and form durable and functional blood vessels in vivo8, 10-13. While the derivation of ECFC from adult peripheral blood has been presented14, 15, here we describe the methodologies for the derivation, cloning, expansion, and in vitro as well as in vivo characterization of ECFCs from the human umbilical CB.

Endothelial colony forming cells (ECFCs) are circulating endothelial cells with robust clonal proliferative potential that display intrinsic in vivo vessel forming ability. Phenotypic and functional characterization of outgrowth endothelial cells derived from CB are important to identify and isolate bona fide ECFCs for potential clinical application in repairing damaged tissues.

Caractérisation phénotypique et fonctionnelle des cellules endothéliales formant colonie dérivés du sang de cordon ombilical humain

Longstanding views of new blood vessel formation via angiogenesis, vasculogenesis, and arteriogenesis have been recently reviewed1. The presence of ...

A Quantitative Fitness Analysis Workflow

Quantitative Fitness Analysis (QFA) is an experimental and computational workflow for comparing fitnesses of microbial cultures grown in parallel1,2,3,4. QFA can be applied to focused observations of single cultures but is most useful for genome-wide genetic interaction or drug screens investigating up to thousands of independent cultures. The central experimental method is the inoculation of independent, dilute liquid microbial cultures onto solid agar plates which are incubated and regularly photographed. Photographs from each time-point are analyzed, producing quantitative cell density estimates, which are used to construct growth curves, allowing quantitative fitness measures to be derived. Culture fitnesses can be compared to quantify and rank genetic interaction strengths or drug sensitivities. The effect on culture fitness of any treatments added into substrate agar (e.g. small molecules, antibiotics or nutrients) or applied to plates externally (e.g. UV irradiation, temperature) can be quantified by QFA.
The QFA workflow produces growth rate estimates analogous to those obtained by spectrophotometric measurement of parallel liquid cultures in 96-well or 200-well plate readers. Importantly, QFA has significantly higher throughput compared with such methods. QFA cultures grow on a solid agar surface and are therefore well aerated during growth without the need for stirring or shaking.
QFA throughput is not as high as that of some Synthetic Genetic Array (SGA) screening methods5,6. However, since QFA cultures are heavily diluted before being inoculated onto agar, QFA can capture more complete growth curves, including exponential and saturation phases3. For example, growth curve observations allow culture doubling times to be estimated directly with high precision, as discussed previously1.
Here we present a specific QFA protocol applied to thousands of S. cerevisiae cultures which are automatically handled by robots during inoculation, incubation and imaging. Any of these automated steps can be replaced by an equivalent, manual procedure, with an associated reduction in throughput, and we also present a lower throughput manual protocol. The same QFA software tools can be applied to images captured in either workflow.
We have extensive experience applying QFA to cultures of the budding yeast S. cerevisiae but we expect that QFA will prove equally useful for examining cultures of the fission yeast S. pombe and bacterial cultures.

Quantitative Fitness Analysis (QFA) is a complementary series of experimental and computational methods for estimating microbial culture fitnesses. QFA estimates the effect of genetic mutations, drugs or other applied treatments on microbe growth. Experiments scaling from focussed analysis of single cultures to thousands of parallel cultures can be designed.

Un flux de travail de remise en forme Analyse quantitative

Quantitative Fitness Analysis (QFA) is an experimental and computational workflow for comparing fitnesses of microbial cultures grown in parallel1,2,3,4. ...

A High Throughput MHC II Binding Assay for Quantitative Analysis of Peptide Epitopes

Biochemical assays with recombinant human MHC II molecules can provide rapid, quantitative insights into immunogenic epitope identification, deletion, or design1,2. Here, a peptide-MHC II binding assay is scaled to 384-well format. The scaled down protocol reduces reagent costs by 75% and is higher throughput than previously described 96-well protocols1,3-5. Specifically, the experimental design permits robust and reproducible analysis of up to 15 peptides against one MHC II allele per 384-well ELISA plate. Using a single liquid handling robot, this method allows one researcher to analyze approximately ninety test peptides in triplicate over a range of eight concentrations and four MHC II allele types in less than 48 hr. Others working in the fields of protein deimmunization or vaccine design and development may find the protocol to be useful in facilitating their own work. In particular, the step-by-step instructions and the visual format of JoVE should allow other users to quickly and easily establish this methodology in their own labs.

Biochemical assays with recombinant human MHC II molecules can provide rapid, quantitative insights into immunogenic epitope identification, deletion, or design. &#160;Here, a peptide-MHC II binding assay scaled to 384-well plates is described. This cost effective format should prove useful in the fields of protein deimmunization and vaccine design and development.

Un essai de liaison à haut débit CMH II pour l&#39;analyse quantitative du peptide épitopes

Biochemical assays with recombinant human MHC II molecules can provide rapid, quantitative insights into immunogenic epitope identification, deletion, or ...

A Strategy for Sensitive, Large Scale Quantitative Metabolomics

Metabolite profiling has been a valuable asset in the study of metabolism in health and disease. However, current platforms have different limiting factors, such as labor intensive sample preparations, low detection limits, slow scan speeds, intensive method optimization for each metabolite, and the inability to measure both positively and negatively charged ions in single experiments. Therefore, a novel metabolomics protocol could advance metabolomics studies. Amide-based hydrophilic chromatography enables polar metabolite analysis without any chemical derivatization. High resolution MS using the Q-Exactive (QE-MS) has improved ion optics, increased scan speeds (256 msec at resolution 70,000), and has the capability of carrying out positive/negative switching. Using a cold methanol extraction strategy, and coupling an amide column with QE-MS enables robust detection of 168 targeted polar metabolites and thousands of additional features simultaneously.&#160; Data processing is carried out with commercially available software in a highly efficient way, and unknown features extracted from the mass spectra can be queried in databases.

Metabolite profiling has been a valuable asset in the study of metabolism in health and disease. Utilizing normal-phased liquid chromatography coupled to high-resolution mass spectrometry with polarity switching and a rapid duty cycle, we describe a protocol to analyze the polar metabolic composition of biological material with high sensitivity, accuracy, and resolution.

Une stratégie pour sensibles à grande échelle quantitatives métabolomique

Metabolite profiling has been a valuable asset in the study of metabolism in health and disease. However, current platforms have different limiting ...

Quantitative Immunofluorescence Assay to Measure the Variation in Protein Levels at Centrosomes

Centrosomes are small but important organelles that serve as the poles of mitotic spindle to maintain genomic integrity or assemble primary cilia to facilitate sensory functions in cells. The level of a protein may be regulated differently at centrosomes than at other .cellular locations, and the variation in the centrosomal level of several proteins at different points of the cell cycle appears to be crucial for the proper regulation of centriole assembly. We developed a quantitative fluorescence microscopy assay that measures relative changes in the level of a protein at centrosomes in fixed cells from different samples, such as at different phases of the cell cycle or after treatment with various reagents. The principle of this assay lies in measuring the background corrected fluorescent intensity corresponding to a protein at a small region, and normalize that measurement against the same for another protein that does not vary under the chosen experimental condition. Utilizing this assay in combination with BrdU pulse and chase strategy to study unperturbed cell cycles, we have quantitatively validated our recent observation that the centrosomal pool of VDAC3 is regulated at centrosomes during the cell cycle, likely by proteasome-mediated degradation specifically at centrosomes.

Here, a novel quantitative fluorescence assay is developed to measure changes in the level of a protein specifically at centrosomes by normalizing that protein&#8217;s fluorescence intensity to that of an appropriate internal standard.

Immunofluorescence quantitative pour mesurer la variation des taux de protéines au centrosomes

Centrosomes are small but important organelles that serve as the poles of mitotic spindle to maintain genomic integrity or assemble primary cilia to ...

Development of a Quantitative Recombinase Polymerase Amplification Assay with an Internal Positive Control

It was recently demonstrated that recombinase polymerase amplification (RPA), an isothermal amplification platform for pathogen detection, may be used to quantify DNA sample concentration using a standard curve. In this manuscript, a detailed protocol for developing and implementing a real-time quantitative recombinase polymerase amplification assay (qRPA assay) is provided. Using HIV-1 DNA quantification as an example, the assembly of real-time RPA reactions, the design of an internal positive control (IPC) sequence, and co-amplification of the IPC and target of interest are all described. Instructions and data processing scripts for the construction of a standard curve using data from multiple experiments are provided, which may be used to predict the concentration of unknown samples or assess the performance of the assay. Finally, an alternative method for collecting real-time fluorescence data with a microscope and a stage heater as a step towards developing a point-of-care qRPA assay is described. The protocol and scripts provided may be used for the development of a qRPA assay for any DNA target of interest.

Provided is a protocol for developing a real-time recombinase polymerase amplification assay to quantify initial concentration of DNA samples using either a thermal cycler or a microscope and stage heater. Also described is the development of an internal positive control. Scripts are provided for processing raw real-time fluorescence data.

Développement d&#39;un Quantitative recombinase polymérase L&#39;amplification Assay avec un contrôle positif interne

It was recently demonstrated that recombinase polymerase amplification (RPA), an isothermal amplification platform for pathogen detection, may be used to ...