Questo progetto è stato sostenuto da una borsa SEED J. Leon Thal del California Institute per la Medicina Rigenerativa. Tobias Henning è stato finanziato da una borsa di studio di ricerca dal tedesco Research Association (DFG, SE 4578/1-2). Vogliamo riconoscere con gratitudine Meneses Juanito per i suoi consigli sulla cultura di cellule staminali embrionali umane.

L&#39;etichettatura di hMSC con Ferucarbotran Questa è la tecnica per l&#39;etichettatura di cellule staminali mesenchimali con Ferucarbotran, un ossido di ferro agente di contrasto per RM: <ol><li> Per iniziare, piastra delle cellule 18-24 ore prima della procedura di etichettatura T75 fiaschi ad una confluenza del 80%. Se si utilizza un piatto diversa cultura, questa è pari a circa 10000 cellule per cm 2. </li><li> Il giorno dopo, iniziare con la preparazione dei mezzi di etichettatura con l&#39;aggiunta di 30 ml di Resovist a 8 ml di siero libertà dei media. Questo etichetta uno T75 pallone in 80% confluenza, corrispondente a una concentrazione di 100 mg Fe / ml media. </li><li> Togliere il mezzo di coltura e lavare le cellule una volta con PBS o senza siero dei media. Questo viene fatto per sbarazzarsi di residui di proteine ​​del siero ed altri costituenti dei media che possono legare il mezzo di contrasto e di etichettatura di efficienza influenza. </li><li> Aggiungi ai media di etichettatura per il pallone e rimettere il pallone in incubatrice. </li><li> Dopo 2 ore, aggiungere 2 ml di FCS modo che la concentrazione finale del 20% FCS è raggiunto. Questo viene fatto per garantire che le cellule non ricevono lo stimolo a differenziare, ma invece crescere nel loro ambiente familiare. </li><li> Incubare le cellule oltre 18 ore. Questo è fatto meglio durante la notte. </li><li> Il giorno dopo, lavare le cellule con PBS, poi trypsinize come al solito. </li><li> Una volta trypsinized, la sospensione cellulare ha bisogno di essere lavati 3 volte per sbarazzarsi di residui, senza mezzo di contrasto nei media. Questo viene fatto con PBS centrifugando le cellule a 400 rcf per 5 minuti. </li><li> La finale pellet cellulare può essere risospeso ed è pronto per ulteriori esperimenti. </li><li> Contare le celle ora, come qualcuno potrebbe essere stato perso durante i passaggi precedenti lavaggio. Inoltre, eseguire test di vitalità a questo punto, utilizzando il test Trypan esclusione blu e prendere alcuni campioni per analisi di spettrometria per misurare l&#39;efficienza di etichettatura. </li></ol> Etichettatura delle cellule staminali embrionali umane con Ferumoxides <ol><li> Per iniziare la targhetta del hESC nei piatti 10cm, come al solito. Questi piatti sono pre-rivestiti con gelatina e sono cellule alimentatore irradiato su di loro. È possibile utilizzare questo protocollo per l&#39;alimentazione priva di culture pure. </li><li> Lasciate che i hESC attaccare e crescere per circa 3-4 giorni in modo da formare colonie di medie dimensioni. Durante questo tempo, in modo che le colonie non crescono alla grande, come le colonie più grandi sono più difficili da rompere più tardi. </li><li> Cellule differenziate possono contaminare queste culture, per cui a seconda della pulizia delle colonie, potrebbe essere necessario sbarazzarsi di culture differenziate da dissezione. </li><li> Preparare il supporto di etichettatura che consiste Ferumoxides ad una concentrazione di mezzi hESC 100μg/ml e pieno. Per questo, abbiamo mix 89μl Ferumoxides e 10 ml di media piena crescita. </li><li> Lavare il piatto una volta con i media completa. </li><li> Aggiungere 10 ml di etichettatura dei media per ogni piatto e incubare le cellule per 4 ore. </li><li> Ora, l&#39;etichettatura è completa. Nel passo successivo, è necessario lavare le cellule e ottenere una sospensione singola cella per un ulteriore uso. Per questo, prima lavare il piatto con PBS. </li><li> Poi, sostituire la PBS con 5 ml di tripsina 0,25% e incubare nell&#39;incubatore per 5 minuti, o fino a quando le cellule staccare. Aiuta a toccare il piatto di frequente. </li><li> Le cellule sono ormai staccati. Tenete presente che se il piatto conteneva le colonie più grandi ci potrebbero essere alcuni cespugli di sinistra. </li><li> Per sbarazzarsi di questi grumi, si può miscelare la sospensione intero una volta con una pipetta sierologica, poi lasciate riposare per altri 2 minuti. </li><li> Noi non usare una pipetta Eppendorf, succhiando come ripetuto delle cellule attraverso la punta sottile può rompere le membrane cellulari. </li><li> Se si osservano residui sono presenti, si può eseguire la sospensione cellulare attraverso un colino cellula 40μm. </li><li> Se tutto ha funzionato correttamente, una sospensione singola cellula esiste, ora che è mescolato con un sacco di detriti, provenienti dal rivestimento in gelatina, il CES-matrice e cellule morte. Per sbarazzarsi di questo, lavare le cellule due volte facendo girare giù a 400 rcf per 5 minuti e risospendere in mezzi di comunicazione completo. </li><li> Ora, il Comitato deve essere isolato dalle cellule alimentatore irradiati. Questo può essere fatto in modo efficiente dal placcatura la sospensione cellulare su un piatto rivestito di gelatina. </li><li> Se il piatto non è manipolato, tutte le cellule si sedimenta giù, ma gli alimentatori che attribuirà più veloce del CES. </li><li> Quindi, se il surnatante viene tolto dopo 45 minuti, dovrebbe contenere principalmente ESC, mentre gli alimentatori dovrebbe principalmente essere allegata al piatto. </li><li> In questo modo, una sospensione singola cella di magneticamente etichettato cellule staminali embrionali umane che possono essere utilizzati per ulteriori esperimenti si ottiene. </li><li> Come nel precedente protocollo, a questo punto, è necessario contare le cellule e prelevare campioni per valutazione della vitalità economica e la misurazione di efficienza etichettatura. </li></ol>

<ol>
	<li>Daldrup-Link, H. E., Rudelius, M., Oostendorp, R. A. J., Settles, M., Piontek, G., Metz, S., Heinzmann, U., Rummeny, E. J., Schlegel, J., Link, T. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Targeting+of+Hematopoietic+Progenitor+Cells+with+MR+Contrast+Agents.">Targeting of Hematopoietic Progenitor Cells with MR Contrast Agents.</a> 228, 760-767 (2003).</li><li>Daldrup-Link, H. E., Rudelius, M., Piontek, G., Metz, S., Brauer, R., Debus, G., Corot, C., Schlegel, J., Link, T. M., Peschel, C., Rummeny, E. J., Oostendorp, R. A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Migration+of+iron+oxide+labeled+human+hematopoietic+progenitor+cells+in+a+xenotransplant+model:+in+vivo+monitoring+using+clinical+magnetic+resonance+imaging+equipment.">Migration of iron oxide labeled human hematopoietic progenitor cells in a xenotransplant model: in vivo monitoring using clinical magnetic resonance imaging equipment.</a> Radiology. 234, 197-205 (2005).</li><li>Henning, T. D., Saborowski, O., Golovko, D., Boddington, S., Bauer, J. S., Fu, Y., Meier, R., Pietsch, H., Sennino, B., McDonald, D. M., Daldrup-Link, H. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+labeling+with+the+positive+MR+contrast+agent.">Cell labeling with the positive MR contrast agent.</a> Gadofluorine M. Eur Radiol. 17, 1226-1234 (2007).</li></ol>

Un non-invasiva rappresentazione delle cellule staminali è fondamentale per il monitoraggio praticamente qualsiasi terapia a base di cellule staminali. Una migliore comprensione della cinetica in vivo delle cellule staminali etichettati, come visualizzato nelle immagini MR, potrebbe aprire la strada ad un razionale e un uso più efficace delle cellule staminali a base di terapie. Dal momento che usiamo mezzi di contrasto clinicamente applicabile e tecniche di imaging, i nostri protocolli presentati devono essere facilmente traducibili in a...

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		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
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<tr>
<td>D-MEM High Glucose</td>
<td>Reagent</td>
<td>Sigma</td>
<td>D5648</td>
<td>&nbsp;</td>
<tr>
<td>Gelatin</td>
<td>Reagent</td>
<td>Sigma</td>
<td>G1890</td>
<td>dilute Gelatin in PBS to final concentration of 0.1 %</td>
</tr>
<tr>
<td>PBS (Ca++ Mg++ freed)</td>
<td>Reagent</td>
<td>GIBCO</td>
<td> 14190-144</td>
<td>&nbsp;</td>
<tr>
<td>Trypsin-EDTA 0.05%</td>
<td>Reagent</td>
<td>Invitrogen</td>
<td>25300-120</td>
<td>&nbsp;</td>
<tr>
<td>Trypsin-EDTA 0.25%</td>
<td>Reagent</td>
<td>Invitrogen</td>
<td>25200-114	</td>
<td>&nbsp;</td>
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<td>FBS characterized</td>
<td>Reagent</td>
<td>Hyclone</td>
<td>SH30071.03</td>
<td>&nbsp;</td>
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<td>Cell Strainer (40 &#x03BC;m Nylon)</td>
<td>Tool</td>
<td>BD Falcon</td>
<td>352340</td>
<td>&nbsp;</td>
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<td>Knockout DMEM</td>
<td>Reagent</td>
<td>GIBCO</td>
<td>10829018</td>
<td>&nbsp;</td>
<tr>
<td>Knockout Serum Replacer</td>
<td>Reagent</td>
<td>GIBCO</td>
<td>10828028</td>
<td>&nbsp;</td>
<tr>
<td>b-Mercaptoethanol</td>
<td>Reagent</td>
<td>Sigma</td>
<td>7522</td>
<td>&nbsp;</td>
<tr>
<td>non-essential amino acids</td>
<td>Reagent</td>
<td>GIBCO</td>
<td>11140050</td>
<td>&nbsp;</td>
<tr>
<td>FGF-2</td>
<td>Reagent</td>
<td>R&D Systems</td>
<td>233-FB-025</td>
<td>&nbsp;</td>
<tr>
<td>Glutamine</td>
<td>Reagent</td>
<td>GIBCO</td>
<td>25030081</td>
<td>&nbsp;</td>
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<td>Penicillin/Streptomycin</td>
<td>Reagent</td>
<td>GIBCO</td>
<td>15140-122</td>
<td>&nbsp;</td>
<tr>
<td>Ferumoxides (Endorem)</td>
<td>Reagent</td>
<td>Guerbet</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Ferucarbotran (Resovist&#174;)</td>
<td>Reagent</td>
<td>Bayer Schering AG</td>
<td>&nbsp;</td>
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labeling hescs and hmscs with iron oxide nanoparticles for non-invasive in vivo tracking with mr imaging

Negli ultimi anni la ricerca sulle cellule staminali ha portato ad una migliore comprensione della biologia dello sviluppo, malattie varie e il suo potenziale impatto sulla medicina rigenerativa. Un metodo non invasivo per monitorare le cellule staminali trapiantate in vivo avrebbe ripetutamente di migliorare notevolmente la nostra capacità di comprendere i meccanismi che la morte di controllo delle cellule staminali e di identificare fattori trofici e di vie di segnalazione che consentono di migliorare l&#39;attecchimento delle cellule staminali. RM ha dimostrato di essere uno strumento efficace per la rappresentazione in vivo di cellule staminali con vicino risoluzione anatomica microscopica. Al fine di individuare le cellule staminali con MR, le cellule devono essere etichettati con cellulari specifici mezzi di contrasto MR. A tal fine, le nanoparticelle di ossido di ferro, come le particelle di ossido di ferro superparamagnetiche (SPIO), vengono applicate, a causa della loro elevata sensibilità per il rilevamento delle cellule e la loro eccellente biocompatibilità. SPIO particelle sono composte da un nucleo di ossido di ferro e un cappotto destrano, carboxydextran o amido, e la funzione creando disomogeneità campo locale, che causano una diminuzione del segnale sulle immagini T2 MR. Questa presentazione dimostrerà le tecniche per l&#39;etichettatura di cellule staminali clinicamente applicabile con mezzi di contrasto RM per la successiva non invasive nel monitoraggio in vivo delle cellule etichettate con la RM.

Watch this Scientific Journal Video about Labeling hESCs and hMSCs with Iron Oxide Nanoparticles for Non-Invasive in vivo Tracking with MR Imaging at JoVE.com

Labeling hESCs and hMSCs with Iron Oxide Nanoparticles for Non-Invasive in vivo Tracking with MR Imaging

Per la valutazione delle terapie con cellule staminali nuovo, è importante non invasiva traccia le cellule iniettate in vivo. Questo video vi mostrerà come etichetta cellule staminali mesenchimali ed embrionali con il ferro mezzi di contrasto a base di ossidi in vivo per la successiva RM in vivo.

Etichettatura hESC e hMSCs con nanoparticelle di ossido di ferro per i non-invasiva in vivo inseguimento con la RM

In recent years, stem cell research has led to a better understanding of developmental biology, various diseases and its potential impact on regenerative ...

labeling-hescs-hmscs-with-iron-oxide-nanoparticles-for-non-invasive

Research

JoVE Journal

Biology

9.7K Views.  Contrast Agent Research Group at the Center for Molecular and Functional Imaging, Department of Radiology, University of California San Francisco. Per la valutazione delle terapie con cellule staminali nuovo, è importante non invasiva traccia le cellule iniettate in vivo. Questo video vi mostrerà come etichetta cellule staminali mesenchimali ed embrionali con il ferro mezzi di contrasto a base di ossidi in vivo per la successiva RM in vivo.

Video: Labeling hESCs and hMSCs with Iron Oxide Nanoparticles for Non-Invasive in vivo Tracking with MR Imaging

Labeling Stem Cells with Fluorescent Dyes for non-invasive Detection with Optical Imaging

Optical imaging (OI) is an easy, fast and inexpensive tool for in vivo monitoring of new stem cell based therapies. The technique is based on ex vivo labeling of stem cells with a fluorescent dye, subsequent intravenous injection of the labeled cells and visualization of their accumulation in specific target organs or pathologies. The presented technique demonstrates how we label human mesenchymal stem cells (hMSC) by simple incubation with the lipophilic fluorescent dye DiD (C67H103CIN2O3S) and how we label human embryonic stem cells (hESC) with the FDA approved fluorescent dye Indocyanine Green (ICG). The uptake mechanism is via adherence and diffusion of the lypophilic dye across the phospholipid cell membrane bilayer. The labeling efficiency is usually improved if the cells are incubated with the dye in serum-free media as opposed to incubation in serum-containing media. Furthermore, the addition of the transfection agent Protamine Sulfate significantly improves contrast agent uptake.

This video shows techniques for labeling of human embryonic stem cells and mesenchymal stem cells with fluorescent dyes. This technique can be used for an in vivo tracking of transplanted stem cells with optical imaging and for histopathological correlations with fluorescence microscopy.

Etichettatura Cellule staminali con le tinture fluorescenti per la rilevazione non invasiva con Optical Imaging

Optical imaging (OI) is an easy, fast and inexpensive tool for in vivo monitoring of new stem cell based therapies. The technique is based on ex vivo ...

Ricerca

Biologia

Non-invasive 3D-Visualization with Sub-micron Resolution Using Synchrotron-X-ray-tomography

Little is known about the internal organization of many micro-arthropods with body sizes below 1 mm. The reasons for that are the small size and the hard cuticle which makes it difficult to use protocols of classical histology. In addition, histological sectioning destroys the sample and can therefore not be used for unique material. Hence, a non-destructive method is desirable which allows to view inside small samples without the need of sectioning.
We used synchrotron X-ray tomography at the European Synchrotron Radiation Facility (ESRF) in Grenoble (France) to non-invasively produce 3D tomographic datasets with a pixel-resolution of 0.7&micro;m. Using volume rendering software, this allows us to reconstruct the internal organization in its natural state without the artefacts produced by histological sectioning. These date can be used for quantitative morphology, landmarks, or for the visualization of animated movies to understand the structure of hidden body parts and to follow complete organ systems or tissues through the samples.

We used synchrotron X-ray tomography at the European Synchrotron Radiation Facility (ESRF) to non-invasively produce 3D tomographic datasets with a pixel-resolution of 0.7&micro;m. Using volume rendering software, this allows the reconstruction of internal structures in their natural state without the artefacts produced by histological sectioning.

Non invasive di visualizzazione 3D con sub-micron Risoluzione Utilizzando sincrotrone a raggi-X, la tomografia

Little is known about the internal organization of many micro-arthropods with body sizes below 1 mm. The reasons for that are the small size and the hard ...

Making MR Imaging Child's Play - Pediatric Neuroimaging Protocol, Guidelines and Procedure

Within the last decade there has been an increase in the use of structural and functional magnetic resonance imaging (fMRI) to investigate the neural basis of human perception, cognition and behavior 1, 2. Moreover, this non-invasive imaging method has grown into a tool for clinicians and researchers to explore typical and atypical brain development. Although advances in neuroimaging tools and techniques are apparent, (f)MRI in young pediatric populations remains relatively infrequent 2. Practical as well as technical challenges when imaging children present clinicians and research teams with a unique set of problems 3, 2. To name just a few, the child participants are challenged by a need for motivation, alertness and cooperation. Anxiety may be an additional factor to be addressed. Researchers or clinicians need to consider time constraints, movement restriction, scanner background noise and unfamiliarity with the MR scanner environment2,4-10. A progressive use of functional and structural neuroimaging in younger age groups, however, could further add to our understanding of brain development. As an example, several research groups are currently working towards early detection of developmental disorders, potentially even before children present associated behavioral characteristics e.g.11. Various strategies and techniques have been reported as a means to ensure comfort and cooperation of young children during neuroimaging sessions. Play therapy 12, behavioral approaches 13, 14,15, 16-18 and simulation 19, the use of mock scanner areas 20,21, basic relaxation 22 and a combination of these techniques 23 have all been shown to improve the participant's compliance and thus MRI data quality. Even more importantly, these strategies have proven to increase the comfort of families and children involved 12. One of the main advances of such techniques for the clinical practice is the possibility of avoiding sedation or general anesthesia (GA) as a way to manage children's compliance during MR imaging sessions 19,20. In the current video report, we present a pediatric neuroimaging protocol with guidelines and procedures that have proven to be successful to date in young children.

Making MR Imaging Child&#039;s Play - Pediatric Neuroimaging Protocol, Guidelines and Procedure

Despite an increase in the use of structural and functional magnetic resonance imaging (fMRI) in humans, the study of young pediatric populations remains a challenge. We present a hands-on, step-by-step video protocol including guidelines for clinicians and researchers intending to perform (f)MRI in young children.

Fare Giocare MR Child Imaging - Protocollo Neuroimaging Pediatrica, linee guida e procedure

Within the last decade there has been an increase in the use of structural and functional magnetic resonance imaging (fMRI) to investigate the neural ...

Tracking Dynamics of Muscle Engraftment in Small Animals by In Vivo Fluorescent Imaging

Muscular dystrophies are a group of degenerative muscle diseases characterized by progressive loss of contractile muscle cells. Currently, there is no curative treatment available. Recent advances in stem cell biology have generated new hopes for the development of effective cell based therapies to treat these diseases. Transplantation of various types of stem cells labeled with fluorescent proteins into muscles of dystrophic animal models has been used broadly in the field. A non-invasive technique with the capability to track the transplanted cell fate longitudinally can further our ability to evaluate muscle engraftment by transplanted cells more accurately and efficiently.
In the present study, we demonstrate that in vivo fluorescence imaging is a sensitive and reliable method for tracking transplanted GFP (Green Fluorescent Protein)-labeled cells in mouse skeletal muscles. Despite the concern about background due to the use of an external light necessary for excitation of fluorescent protein, we found that by using either nude mouse or eliminating hair with hair removal reagents much of this problem is eliminated. Using a CCD camera, the fluorescent signal can be detected in the tibialis anterior (TA) muscle after injection of 5 x 105 cells from either GFP transgenic mice or eGFP transduced myoblast culture. For more superficial muscles such as the extensor digitorum longus (EDL), injection of fewer cells produces a detectable signal. Signal intensity can be measured and quantified as the number of emitted photons per second in a region of interest (ROI). Since the acquired images show clear boundaries demarcating the engrafted area, the size of the ROI can be measured as well. If the legs are positioned consistently every time, the changes in total number of photons per second per muscle and the size of the ROI reflect the changes in the number of engrafted cells and the size of the engrafted area. Therefore the changes in the same muscle over time are quantifiable. In vivo fluorescent imaging technique has been used primarily to track the growth of tumorogenic cells, our study shows that it is a powerful tool that enables us to track the fate of transplanted stem cells.

Tracking Dynamics of Muscle Engraftment in Small Animals by In Vivo Fluorescent Imaging

We describe an in vivo fluorescence imaging protocol to monitor muscle regeneration by GFP-labeled myoblasts after transplantation into skeletal muscles of both healthy and dystrophic mice. This protocol can be adapted to study muscle regeneration by transplantation of other types of cells and in other muscular conditions as well.

Monitoraggio Dinamica di attecchimento muscolare nei piccoli animali da In Vivo Fluorescente Imaging

Muscular dystrophies are a group of degenerative muscle diseases characterized by progressive loss of contractile muscle cells. Currently, there is no ...

Lineage Labeling of Zebrafish Cells with Laser Uncagable Fluorescein Dextran

A central problem in developmental biology is to deduce the origin of the myriad cell types present in vertebrates as they arise from undifferentiated precursors. Researchers have employed various methods of lineage labeling, such as DiI labeling1 and pressure injection of traceable enzymes2 to ascertain cell fate at later stages of development in model systems. The first fate maps in zebrafish (Danio rerio) were assembled by iontophoretic injection of fluorescent dyes, such as rhodamine dextran, into single cells in discrete regions of the embryo and tracing the labeled cell's fate over time3-5. While effective, these methods are technically demanding and require specialized equipment not commonly found in zebrafish labs. Recently, photoconvertable fluorescent proteins, such as Eos and Kaede, which irreversibly switch from green to red fluorescence when exposed to ultraviolet light, are seeing increased use in zebrafish6-8. The optical clarity of the zebrafish embryo and the relative ease of transgenesis have made these particularily attractive tools for lineage labeling and to observe the migration of cells in vivo7. Despite their utility, these proteins have some disadvantages compared to dye-mediated lineage labeling methods. The most crucial is the difficulty we have found in obtaining high 3-D resolution during photoconversion of these proteins. In this light, perhaps the best combination of resolution and ease of use for lineage labeling in zebrafish makes use of caged fluorescein dextran, a fluorescent dye that is bound to a quenching group that masks its fluorescence9. The dye can then be "uncaged" (released from the quenching group) within a specific cell using UV light from a laser or mercury lamp, allowing visualization of its fluorescence or immunodetection. Unlike iontophoretic methods, caged fluorescein can be injected with standard injection apparatuses and uncaged with an epifluorescence microscope equipped with a pinhole10. In addition, antibodies against fluorescein detect only the uncaged form, and the epitope survives fixation well11. Finally, caged fluorescein can be activated with very high 3-D resolution, especially if two-photon microscopy is employed 12,13. This protocol describes a method of lineage labeling by caged fluorescein and laser uncaging. Subsequenctly, uncaged fluorescein is detected simultaneously with other epitopes such as GFP by labeling with antibodies.

This protocol delineates a way to label and trace the fate of small groups of cells zebrafish embryos using UV-uncaging of caged fluorescein, followed by whole mount immunolabeling to amplify the signal from the uncaged fluorescein.

Etichettatura stirpe di cellule Zebrafish con laser Uncagable Fluoresceina Destrano

A central problem in developmental biology is to deduce the origin of the myriad cell types present in vertebrates as they arise from undifferentiated ...

Measuring Cell Cycle Progression Kinetics with Metabolic Labeling and Flow Cytometry

Precise control of the initiation and subsequent progression through the various phases of the cell cycle are of paramount importance in proliferating cells. Cell cycle division is an integral part of growth and reproduction and deregulation of key cell cycle components have been implicated in the precipitating events of carcinogenesis 1,2. Molecular agents in anti-cancer therapies frequently target biological pathways responsible for the regulation and coordination of cell cycle division 3. Although cell cycle kinetics tend to vary according to cell type, the distribution of cells amongst the four stages of the cell cycle is rather consistent within a particular cell line due to the consistent pattern of mitogen and growth factor expression. Genotoxic events and other cellular stressors can result in a temporary block of cell cycle progression, resulting in arrest or a temporary pause in a particular cell cycle phase to allow for instigation of the appropriate response mechanism. 
The ability to experimentally observe the behavior of a cell population with reference to their cell cycle progression stage is an important advance in cell biology. Common procedures such as mitotic shake off, differential centrifugation or flow cytometry-based sorting are used to isolate cells at specific stages of the cell cycle 4-6. These fractionated, cell cycle phase-enriched populations are then subjected to experimental treatments. Yield, purity and viability of the separated fractions can often be compromised using these physical separation methods. As well, the time lapse between separation of the cell populations and the start of experimental treatment, whereby the fractionated cells can progress from the selected cell cycle stage, can pose significant challenges in the successful implementation and interpretation of these experiments.
Other approaches to study cell cycle stages include the use of chemicals to synchronize cells. Treatment of cells with chemical inhibitors of key metabolic processes for each cell cycle stage are useful in blocking the progression of the cell cycle to the next stage. For example, the ribonucleotide reductase inhibitor hydroxyurea halts cells at the G1/S juncture by limiting the supply of deoxynucleotides, the building blocks of DNA. Other notable chemicals include treatment with aphidicolin, a polymerase alpha inhibitor for G1 arrest, treatment with colchicine and nocodazole, both of which interfere with mitotic spindle formation to halt cells in M phase and finally, treatment with the DNA chain terminator 5-fluorodeoxyridine to initiate S phase arrest 7-9. Treatment with these chemicals is an effective means of synchronizing an entire population of cells at a particular phase. With removal of the chemical, cells rejoin the cell cycle in unison. Treatment of the test agent following release from the cell cycle blocking chemical ensures that the drug response elicited is from a uniform, cell cycle stage-specific population. However, since many of the chemical synchronizers are known genotoxic compounds, teasing apart the participation of various response pathways (to the synchronizers vs. the test agents) is challenging. 
Here we describe a metabolic labeling method for following a subpopulation of actively cycling cells through their progression from the DNA replication phase, through to the division and separation of their daughter cells. Coupled with flow cytometry quantification, this protocol enables for measurement of kinetic progression of the cell cycle in the absence of either mechanically- or chemically- induced cellular stresses commonly associated with other cell cycle synchronization methodologies 10. In the following sections we will discuss the methodology, as well as some of its applications in biomedical research.

Tracking subtle changes in the progression and kinetics of cell cycle stages can be accomplished by use of a combination of metabolic labeling of nucleic acids with BrdU and total genomic DNA staining via Propidium Iodide. This method avoids the need of chemical synchronization of cycling cells, thereby preventing the introduction of non-specific DNA damage, which in turn affects cell cycle progression.

Cella di misura Kinetics progressione del ciclo con la marcatura metabolica e citometria a flusso

Precise control of the initiation and subsequent progression through the various phases of the cell cycle are of paramount importance in proliferating ...

Metabolic Labeling of Leucine Rich Repeat Kinases 1 and 2 with Radioactive Phosphate

Leucine rich repeat kinases 1 and 2 (LRRK1 and LRRK2) are paralogs which share a similar domain organization, including a serine-threonine kinase domain, a Ras of complex proteins domain (ROC), a C-terminal of ROC domain (COR), and leucine-rich and ankyrin-like repeats at the N-terminus. The precise cellular roles of LRRK1 and LRRK2 have yet to be elucidated, however LRRK1 has been implicated in tyrosine kinase receptor signaling1,2, while LRRK2 is implicated in the pathogenesis of Parkinson's disease3,4. In this report, we present a protocol to label the LRRK1 and LRRK2 proteins in cells with 32P orthophosphate, thereby providing a means to measure the overall phosphorylation levels of these 2 proteins in cells. In brief, affinity tagged LRRK proteins are expressed in HEK293T cells which are exposed to medium containing 32P-orthophosphate. The 32P-orthophosphate is assimilated by the cells after only a few hours of incubation and all molecules in the cell containing phosphates are thereby radioactively labeled. Via the affinity tag (3xflag) the LRRK proteins are isolated from other cellular components by immunoprecipitation. Immunoprecipitates are then separated via SDS-PAGE, blotted to PVDF membranes and analysis of the incorporated phosphates is performed by autoradiography (32P signal) and western detection (protein signal) of the proteins on the blots. The protocol can readily be adapted to monitor phosphorylation of any other protein that can be expressed in cells and isolated by immunoprecipitation.

Leucine rich repeat kinases 1 and 2 (LRRK1 and LRRK2) are multidomain proteins which encode both GTPase and kinase domains and which are phosphorylated in cells. Here, we present a protocol to label LRRK1 and LRRK2 in cells with 32P orthophosphate, thereby providing a means to measure their overall cellular phophorylation levels.

Metabolica Etichettatura di leucina Rich Repeat chinasi 1 e 2 con Radioactive fosfato

Leucine rich repeat kinases 1 and 2 (LRRK1 and LRRK2) are paralogs which share a similar domain organization, including a serine-threonine kinase domain, ...

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.

In Vivo inseguimento 4-dimensionale di emopoietiche staminali e progenitrici celle di topo adulto cranica di Midollo Osseo

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

Fluorescence Imaging with One-nanometer Accuracy (FIONA)

Fluorescence imaging with one-nanometer accuracy (FIONA) is a simple but useful technique for localizing single fluorophores with nanometer precision in the x-y plane. Here a summary of the FIONA technique is reported and examples of research that have been performed using FIONA are briefly described. First, how to set up the required equipment for FIONA experiments, i.e., a total internal reflection fluorescence microscopy (TIRFM), with details on aligning the optics, is described. Then how to carry out a simple FIONA experiment on localizing immobilized Cy3-DNA single molecules using appropriate protocols, followed by the use of FIONA to measure the 36 nm step size of a single truncated myosin Va motor labeled with a quantum dot, is illustrated. Lastly, recent effort to extend the application of FIONA to thick samples is reported. It is shown that, using a water immersion objective and quantum dots soaked deep in sol-gels and rabbit eye corneas (&#62;200 &#181;m), localization precision of 2-3 nm can be achieved.

Fluorescence Imaging with One-nanometer Accuracy FIONA

Single fluorophores can be localized with nanometer precision using FIONA. Here a summary of the FIONA technique is reported, and how to carry out FIONA experiments is described.

Imaging di fluorescenza con One nanometri Precisione (FIONA)

Fluorescence imaging with one-nanometer accuracy (FIONA) is a simple but useful technique for localizing single fluorophores with nanometer precision in ...

Fecal Glucocorticoid Analysis: Non-invasive Adrenal Monitoring in Equids

Adrenal activity can be assessed in the equine species by analysis of feces for corticosterone metabolites. During a potentially aversive situation, corticotrophin releasing hormone (CRH) is released from the hypothalamus in the brain. This stimulates the release of adrenocorticotrophic hormone (ACTH) from the pituitary gland, which in turn stimulates release of glucocorticoids from the adrenal gland. In horses the glucocorticoid corticosterone is responsible for several adaptations needed to support equine flight behaviour and subsequent removal from the aversive situation. Corticosterone metabolites can be detected in the feces of horses and assessment offers a non-invasive option to evaluate long term patterns of adrenal activity. Fecal assessment offers advantages over other techniques that monitor adrenal activity including blood plasma and saliva analysis. The non-invasive nature of the method avoids sampling stress which can confound results. It also allows the opportunity for repeated sampling over time and is ideal for studies in free ranging horses. This protocol describes the enzyme linked immunoassay (EIA) used to assess feces for corticosterone, in addition to the associated biochemical validation.

Adrenal activity can be assessed in the equine species by analysis of feces for corticosterone metabolites. The method offers a non-invasive option to assess long term patterns in both domestic and free ranging horses. This protocol describes the enzyme linked immunoassay involved and the associated biochemical validation.

Fecale Analisi glucocorticoidi: non invasivo di monitoraggio surrenale in equidi

Adrenal activity can be assessed in the equine species by analysis of feces for corticosterone metabolites. During a potentially aversive situation, ...