The authors dedicate this paper in honor of Prof. Gilberto Oliveira-Castro who introduced research in intercellular communication by gap junctions in Brazil. This work was funded by Capes, CNPQ and Faperj.

<html> 1. Preparazione di cellule <ol><li> Mantenere una cultura di una linea timica cellule epiteliali (IT76M1) o cellule da testare in un incubatore (37 ° C / 5% di CO 2). </li><li> Lavare le cellule con PBS 1x (ripetere questo punto 3x). </li><li> Aggiungere tripsina alle cellule per 5 min. </li><li> Aggiungere mezzo (il doppio del volume di tripsina aggiunto al punto 1.3) con 10% FBS (siero bovino fetale) alle cellule con tripsina e centrifugare (800 xg per 5 min). </li><li> Contare le cellule in un emocitometro. </li><li> Regolare la densità di cellule a seconda del tipo di cellule come le cellule devono essere in stretto contatto con l&#39;altro per consentire l&#39;accoppiamento. Nota: Nel nostro caso, abbiamo utilizzato 3 x 10 5 cellule per 35 millimetri Petri. </li></ol> 2. Preparazione Micropipetta <ol><li> Tirare la micropipetta come specificato da una micropipetta capillare di vetro (1,5 mm di diametro) per una finale di 0,2 micron di diametro in modo da raggiungere una resistenza finale di circa 30 MWf &quot;&gt; 17, 18. NOTA: In alternativa, pipette di iniezione possono essere acquistati. La resistenza dipende dalla dimensione della cella, per esempio sarebbe necessario per cellule acinose pancreatiche un microelettrodo resistenza maggiore, per esempio (100-150 MW) 19. Un problema comune che potrebbe verificarsi è la precipitazione della soluzione giallo Lucifero che può ostacolare la micropipetta e possono richiedere filtrazione o centrifugazione prima. Prima dell&#39;iniezione, la micropipetta deve essere analizzato al microscopio per rilevare se vi è un&#39;ostruzione o qualsiasi tipo di interruzione 13. La micropipetta può essere testato iniettando LY con la punta micropipetta all&#39;interno di una soluzione salina. </li></ol> 3. Test del Micropipetta <ol><li> Preparare la soluzione giallo Lucifero (5%) in 150 mmol / L LiCI e caricare la micropipetta con una siringa o riempimento (messo in esso LY Solution). </li><li> Posizionare il micropipette over da 35 mm piastra di Petri con le cellule IT76M1 sulla workstation microiniezione e immergere la punta della micropipetta di vetro nel mezzo cellulare. Focus sul micropipetta ed eseguire un test di tinteggiatura che scorre mediante l&#39;applicazione di un impulso. </li></ol> 4. Single-cell Lucifer Yellow microiniezione <ol><li> Mettere a fuoco il microscopio proprio sopra lo strato di cellule con un alto fi cazione ingrandimento (40X), quindi abbassare lentamente la pipetta alle cellule utilizzando il micromanipolatore. </li><li> Perforare la cella di destinazione quando la punta è abbastanza vicino a toccare la membrana cellulare, e applicare un piccolo impulso iperpolarizzante di introdurre il LY nella cella. La tensione applicata dipende dalla carica netta di colorante da iniettare. In alternativa, alcuni altri coloranti possono essere usati con questa tecnica come mostrato nella Tabella 1. Nota: In linea di principio qualsiasi colorante idrofilo con MW meno di 1KDa potrebbe essere utilizzato. Tuttavia, la velocità di trasferimento può variare a seconda del peso e idrofilia. Inoltre, utrasferimento nspecific del colorante utilizzato deve essere valutata. </li><li> Catturare le immagini delle cellule 3 minuti dopo l&#39;iniezione di tintura o di fare un piccolo film con lasso di tempo la microscopia (30 fps). NOTA: Un approccio simile potrebbe essere visto in Hitomi et al (2015) 20. Per evitare comunicazione da ponti intercellulari (mitosi incompleta), un co-iniezione di rhodamin destrano (da 2 a 10 KDa), che non passa attraverso giunzioni gap ma passa attraverso ponti intercellulari e certi tipi di nanotubuli è raccomandato come mostrato in figura 2 . </li></ol>

<ol>
	<li>Bennett, M. V., 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=Gap+junctions:+new+tools,+new+answers,+new+questions.">Gap junctions: new tools, new answers, new questions.</a> Neuron. 6 (3), 305-320 (1991).</li><li>Orellana, J. A., Martinez, A. D., Retamal, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gap+junction+channels+and+hemichannels+in+the+CNS:+Regulation+by+signaling+molecules.">Gap junction channels and hemichannels in the CNS: Regulation by signaling molecules.</a> Neuropharmacology. , (2013).</li><li>Peracchia, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+correlates+of+gap+junction+permeation.">Structural correlates of gap junction permeation.</a> Int Rev Cytol. 66, 81-146 (1980).</li><li>Loewenstein, W. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Junctional+intercellular+communication+and+the+control+of+growth.">Junctional intercellular communication and the control of growth.</a> Biochim Biophys Acta. 560 (1), 1-65 (1979).</li><li>Alves, L. A., 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=Functional+gap+junctions+in+thymic+epithelial+cells+are+formed+by+connexin+43.">Functional gap junctions in thymic epithelial cells are formed by connexin 43.</a> Eur.J Immunol. 25 (2), 431-437 (1995).</li><li>Alves, L. A., 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=Are+there+functional+gap+junctions+or+junctional+hemichannels+in+macrophages?.">Are there functional gap junctions or junctional hemichannels in macrophages?.</a> Blood. 88 (1), 328-334 (1996).</li><li>Fonseca, P. 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=Characterization+of+connexin+30.3+and+43+in+thymocytes.">Characterization of connexin 30.3 and 43 in thymocytes.</a> Immunology letters. 94 (1-2), 65-75 (2004).</li><li>Nihei, O. K., 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=Modulatory+effects+of+cAMP+and+PKC+activation+on+gap+junctional+intercellular+communication+among+thymic+epithelial+cells.">Modulatory effects of cAMP and PKC activation on gap junctional intercellular communication among thymic epithelial cells.</a> BMC Cell Biol. 11, 3 (2010).</li><li>Czyz, J., Szpak, K., Madeja, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+connexins+in+prostate+cancer+promotion+and+progression.">The role of connexins in prostate cancer promotion and progression.</a> Nat Rev Urol. 9 (5), 274-282 (2012).</li><li>El-Saghir, J. A., El-Habre, E. T., El-Sabban, M. E., Talhouk, R. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Connexins:+a+junctional+crossroad+to+breast+cancer.">Connexins: a junctional crossroad to breast cancer.</a> Int J Dev Biol. 55 (7-9), 773-780 (2011).</li><li>Cea, L. A., 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=Connexin-+and+pannexin-based+channels+in+normal+skeletal+muscles+and+their+possible+role+in+muscle+atrophy.">Connexin- and pannexin-based channels in normal skeletal muscles and their possible role in muscle atrophy.</a> J Membr Biol. 245 (8), 423-436 (2012).</li><li>Cotrina, M. L., Nedergaard, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Brain+connexins+in+demyelinating+diseases:+therapeutic+potential+of+glial+targets.">Brain connexins in demyelinating diseases: therapeutic potential of glial targets.</a> Brain Res. 1487, 61-68 (2012).</li><li>Park, H. a. n. -. A., R, S., Khanna, S. a. v. i. t. a., Sen, C. h. a. n. d. a. n. . K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Current+Technologies+in+Single-Cell+Microinjection+and+Application+to+Study+Signal+Transduction.">Current Technologies in Single-Cell Microinjection and Application to Study Signal Transduction.</a> Methods in Redox Signaling. , (2010).</li><li>Abbaci, M., Barberi-Heyob, M., Blondel, W., Guillemin, F., Didelon, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Advantages+and+limitations+of+commonly+used+methods+to+assay+the+molecular+permeability+of+gap+junctional+intercellular+communication.">Advantages and limitations of commonly used methods to assay the molecular permeability of gap junctional intercellular communication.</a> Biotechniques. 45 (1), 33-52 (2008).</li><li>Stewart, W. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+connections+between+cells+as+revealed+by+dye-coupling+with+a+highly+fluorescent+naphthalimide+tracer.">Functional connections between cells as revealed by dye-coupling with a highly fluorescent naphthalimide tracer.</a> Cell. 14 (3), 741-759 (1978).</li><li>Meda, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Probing+the+function+of+connexin+channels+in+primary+tissues.">Probing the function of connexin channels in primary tissues.</a> Methods. 20 (2), 232-244 (2000).</li><li>Klaunig, J. E., Shi, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+gap+junctional+intercellular+communication.">Assessment of gap junctional intercellular communication.</a> Curr Protoc Toxicol. , (2009).</li><li>Hanani, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lucifer+yellow+-+an+angel+rather+than+the+devil.">Lucifer yellow - an angel rather than the devil.</a> J Cell Mol Med. 16 (1), 22-31 (2012).</li><li>Orci, L., Biochemistry, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Blockage+of+Cell-to-Cell+Communication+within+Pancreatic+Acini+Is+Associated+with+Increased+Basal+Release+of+Amylase+Materials+and+Methods+Preparation+of+Acini.">Blockage of Cell-to-Cell Communication within Pancreatic Acini Is Associated with Increased Basal Release of Amylase Materials and Methods Preparation of Acini.</a> Cell. 103 (August), 475-483 (1986).</li><li>Hitomi, M., 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=Differential+connexin+function+enhances+self-renewal+in+glioblastoma.">Differential connexin function enhances self-renewal in glioblastoma.</a> Cell Rep. 11 (7), 1031-1042 (2015).</li><li>Nihei, O. 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The authors have no conflicts of interest.

Al fine di verificare la presenza di funzionali gap junction intercellulare, l&#39;uso di rivelatori, che sono membrana impermeabile, anche se permeabile da canali intercellulari sono necessari 16. Fluoresceina, il primo colorante fluorescente per osservare cellula-cellula di accoppiamento 22, è permeabile tra membrane non giunzionali 3 ed è stato quindi sostituito da Lucifer colorante giallo 15. Attualmente, per trovare la...

Giunzioni intercellulari sono canali che permettono l&#39;intercomunicazione tra cellule vicine 1. Questa comunicazione connette due o più celle confinanti, dove ognuno contribuisce con connessone o hemichannel per formare il canale intercellulare. In cellule di mammifero, la connessone è formata da sei connessine, monomeri con quattro domini transmembrana e un C e terminale N all&#39;interno del citoplasma 2. Giunzioni non solo permettono il flusso di ioni, secondi messaggeri e piccoli metaboliti, ma contribuiscono anche a molte forme di comunicazione cellulare in molti processi fisiologici, come la trasmissione sinaptica, contrazione cardiaca, la crescita e la differenziazione cellulare 3, 4, 5, 6, 7, 8. Inoltre giunzioni sono stati associati conmolte malattie tra cui il cancro 9, 10, 11 atrofia muscolare, alcune malattie genetiche e malattie demielinizzanti 12. Questo tipo di crosstalk intercellulare può essere valutata mediante diversi metodi 13, 14, 15, 16. In questo lavoro, si mostra come eseguire una microiniezione cella singola di Lucifero giallo di visualizzare la comunicazione cellulare attraverso gap giunzioni nelle cellule viventi. Discutiamo come preparare le cellule e la micropipetta, l&#39;uso del micromanipolatore e l&#39;iniezione di Lucifero colorante giallo in una linea di cellule epiteliali del timo. Solitamente, questa procedura sperimentale potrebbe essere analizzato dalla media delle celle collegate alla cella caricato con colorante. Inoltre, questo metodo può essere usato con altri coloranti fluorescenti con peso molecolare inferiore del gapgiunzioni cut-off, che è di circa 1.000 dalton.

<table border="0" cellpadding="0" cellspacing="0" width="1228">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:195px;">Lucifer yellow</td>
			<td style="width:71px;">Sigma</td>
			<td style="width:137px;">L0259</td>
			<td style="width:827px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:195px;">Lithium Chloride</td>
			<td style="width:71px;">Sigma</td>
			<td style="width:137px;">L4408</td>
			<td style="width:827px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:195px;">PBS tablets</td>
			<td style="width:71px;">Sigma&#160;</td>
			<td style="width:137px;">P4417</td>
			<td style="width:827px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:195px;">RPMI</td>
			<td style="width:71px;">Sigma</td>
			<td style="width:137px;">R4130</td>
			<td style="width:827px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:195px;">Bovine fetal serum</td>
			<td style="width:71px;">Cultilab</td>
			<td style="width:137px;"></td>
			<td style="width:827px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:195px;">Trypsin</td>
			<td style="width:71px;">Sigma</td>
			<td style="width:137px;">T4799</td>
			<td style="width:827px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Microscope</td>
			<td style="width:71px;">Nikon</td>
			<td style="width:137px;">TE-2000</td>
			<td>For microinjection experiments, one needs an inverted fluorescence microscope and &#64257;lters for &#64258;uorescent microscopy</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">vibration-insulated table&#160;</td>
			<td style="width:71px;">Newport</td>
			<td style="width:137px;">VH3036W-OPT</td>
			<td>A vibration-insulated table is needed to protect the experiments from vibration and avoid cell damage</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Micromanipulator</td>
			<td style="width:71px;">Narishige</td>
			<td style="width:137px;">MMO-203</td>
			<td>This equipment allows precision adjustments of the micropipette, which is needed for cell micro injection.</td>
		</tr>
		<tr height="100">
			<td height="100" style="height:100px;">Current Generator&#160;</td>
			<td style="width:71px;">Digitimer</td>
			<td style="width:137px;">DS2</td>
			<td>To produce the dye flow through the micropipette, a current below one nano ampere was given using a current generator with an electrode inside the micropipette or an amplifier which has a capacitance compensation circuit (old electrometer) or current injection functions of new patch clamp amplifiers, and the ground wire submersed in the plate dish. Alternatively, the dye can be injected by a pneumatic microinjector, following the factory recommendations.&#160;&#160;&#160;</td>
		</tr>
	</tbody>
</table>

single-cell microinjection for cell communication analysis

Gap junctions are intercellular channels that allow the communication of neighboring cells. This communication depends on the contribution of a hemichannel by each neighboring cell to form the gap junction. In mammalian cells, the hemichannel is formed by six connexins, monomers with four transmembrane domains and a C and N terminal within the cytoplasm. Gap junctions permit the exchange of ions, second messengers, and small metabolites. In addition, they have important roles in many forms of cellular communication within physiological processes such as synaptic transmission, heart contraction, cell growth and differentiation. We detail how to perform a single-cell microinjection of Lucifer Yellow to visualize cellular communication via gap-junctions in living cells. It is expected that in functional gap junctions, the dye will diffuse from the loaded cell to the connected cells. It is a very useful technique to study gap junctions since you can evaluate the diffusion of the fluorescence in real time. We discuss how to prepare the cells and the micropipette, how to use a micromanipulator and inject a low molecular weight fluorescent dye in an epithelial cell line.

Timica linea di cellule epiteliali IT-76MI sono stati utilizzati per valutare l&#39;accoppiamento colorante da giunzioni in quanto queste cellule sono state descritte per esprimere giunzioni funzionali formati da connessina 43 21. La Figura 1 mostra l&#39;iniezione di Lucifer Yellow quando applicato in una cella sotto la punta della pipetta. Dopo alcuni minuti, celle collegate diventano fluorescenti (asterischi) indica la diffusione del colorante fluorescente attr...

Watch this Scientific Journal Video about Single-cell Microinjection for Cell Communication Analysis at JoVE.com

Single-cell Microinjection for Cell Communication Analysis

Descriviamo qui come eseguire una microiniezione cella singola di Lucifero giallo di visualizzare la comunicazione cellulare attraverso gap giunzioni nelle cellule viventi, e fornire alcuni suggerimenti utili. Ci aspettiamo che questo articolo vi aiuterà a tutti di valutare il grado di accoppiamento cellulare a causa di giunzioni funzionali. Tutto qui descritto potrebbe essere, in linea di principio, atto ad altri coloranti fluorescenti con peso molecolare inferiore a 1000 Daltons.

Microiniezione cella singola per l&#39;analisi cellulare comunicazione

Gap junctions are intercellular channels that allow the communication of neighboring cells. This communication depends on the contribution of a ...

single-cell-microinjection-for-cell-communication-analysis

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JoVE Journal

Biology

11.2K Views.  Oswaldo Cruz Foundation.  Descriviamo qui come eseguire una microiniezione cella singola di Lucifero giallo di visualizzare la comunicazione cellulare attraverso gap giunzioni nelle cellule viventi, e fornire alcuni suggerimenti utili. Ci aspettiamo che questo articolo vi aiuterà a tutti di valutare il grado di accoppiamento cellulare a causa di giunzioni funzionali. Tutto qui descritto potrebbe essere, in linea di principio, atto ad altri coloranti fluorescenti con peso molecolare inferiore a 1...

Video: Single-cell Microinjection for Cell Communication Analysis

Single Cell Transfection in Chick Embryos

A central theme in developmental biology is the diversification of lineages and the elucidation of underlying molecular mechanisms. This entails a thorough analysis of the fates of single cells under normal and experimental conditions. To this end, transfection methods that target single progenitors are a prerequisite. We describe here a technically straightforward method for transfecting single cells in chicken tissues in-ovo, allowing reliable lineage tracing as well as genetic manipulation. Specific tissue domains are targeted within the somite or neural tube, and DNA is injected directly into the epithelium of interest, resulting in sporadic transfection of single cells. Using reporters, clonal populations may consequently be traced for up to three days, and behavior of genetically manipulated clonal populations can be compared with that of controls. This method takes advantage of the accessibility of the chick embryo along with emerging tools for genetic manipulation. We compare and discuss its advantages over the widely-used electroporation method, and possible applications and use in additional in-vivo models are also suggested. We advocate the use of this method as a significant addition and complement for existing lineage tracing and genetic interference tools.

Using fine tip micropipettes we inject plasmid DNA into subdomains of chicken somites or neural tubes. The concentration of the plasmid is adjusted to generate single transfected cells. We then allow the cells to develop into clonal populations.

Cella Transfection singola in embrioni di pollo

A central theme in developmental biology is the diversification of lineages and the elucidation of underlying molecular mechanisms. This entails a ...

Ricerca

Biologia

Single Cell Fate Mapping in Zebrafish

The ability to differentially label single cells has important implications in developmental biology. For instance, determining how hematopoietic, lymphatic, and blood vessel lineages arise in developing embryos requires fate mapping and lineage tracing of undifferentiated precursor cells. Recently, photoactivatable proteins which include: Eos1, 2, PAmCherry3, Kaede4-7, pKindling8, and KikGR9, 10 have received wide interest as cell tracing probes. The fluorescence spectrum of these photosensitive proteins can be easily converted with UV excitation, allowing a population of cells to be distinguished from adjacent ones. However, the photoefficiency of the activated protein may limit long-term cell tracking11. As an alternative to photoactivatable proteins, caged fluorescein-dextran has been widely used in embryo model systems7, 12-14. Traditionally, to uncage fluorescein-dextran, UV excitation from a fluorescence lamp house or a single photon UV laser has been used; however, such sources limit the spatial resolution of photoactivation. Here we report a protocol to fate map, lineage trace, and detect single labeled cells. Single cells in embryos injected with caged fluorescein-dextran are photoactivated with near-infrared laser pulses produced from a titanium sapphire femtosecond laser. This laser is customary in all two-photon confocal microscopes such as the LSM 510 META NLO microscope used in this paper. Since biological tissue is transparent to near-infrared irradiation15, the laser pulses can be focused deep within the embryo without uncaging cells above or below the selected focal plane. Therefore, non-linear two-photon absorption is induced only at the geometric focus to uncage fluorescein-dextran in a single cell. To detect the cell containing uncaged fluorescein-dextran, we describe a simple immunohistochemistry protocol16 to rapidly visualize the activated cell. The activation and detection protocol presented in this paper is versatile and can be applied to any model system. 
Note: The reagents used in this protocol can be found in the table appended at the end of the article.

A method is described to photoactivate single cells containing a caged fluorescent protein using two-photon absorption from a Ti:Sapphire femtosecond laser oscillator. To fate map the photoactivated cell, immunohistochemistry is used. This technique can be applied to any cell type.

Singolo Destino Mapping di celle in Zebrafish

The ability to differentially label single cells has important implications in developmental biology. For instance, determining how hematopoietic, ...

Single Cell Transcriptional Profiling of Adult Mouse Cardiomyocytes

While numerous studies have examined gene expression changes from homogenates of heart tissue, this prevents studying the inherent stochastic variation between cells within a tissue. Isolation of pure cardiomyocyte populations through a collagenase perfusion of mouse hearts facilitates the generation of single cell microarrays for whole transcriptome gene expression, or qPCR of specific targets using nanofluidic arrays. We describe here a procedure to examine single cell gene expression profiles of cardiomyocytes isolated from the heart. This paradigm allows for the evaluation of metrics of interest which are not reliant on the mean (for example variance between cells within a tissue) which is not possible when using conventional whole tissue workflows for the evaluation of gene expression (Figure 1). We have achieved robust amplification of the single cell transcriptome yielding micrograms of double stranded cDNA that facilitates the use of microarrays on individual cells. In the procedure we describe the use of NimbleGen arrays which were selected for their ease of use and ability to customize their design. Alternatively, a reverse transcriptase - specific target amplification (RT-STA) reaction, allows for qPCR of hundreds of targets by nanofluidic PCR. Using either of these approaches, it is possible to examine the variability of expression between cells, as well as examining expression profiles of rare cell types from within a tissue. Overall, the single cell gene expression approach allows for the generation of data that can potentially identify idiosyncratic expression profiles that are typically averaged out when examining expression of millions of cells from typical homogenates generated from whole tissues.

Single cell expression profiling allows the detailed gene expression analysis of individual cells. We describe methods for the isolation of cardiomyocytes, and preparing the resulting lysates for either whole transcriptome microarray or qPCR of specific targets.

Cella singola Profiling trascrizionale dei cardiomiociti adulti mouse

While numerous studies have examined gene expression changes from homogenates of heart tissue, this prevents studying the inherent stochastic variation ...

Analysis of Single-cell Gene Transcription by RNA Fluorescent In Situ Hybridization (FISH)

Adhesion of Plasmodium falciparum infected erythrocytes (IE) to human endothelial receptors during malaria infections is mediated by expression of PfEMP1 protein variants encoded by the var genes.
The haploid P. falciparum genome harbors approximately 60 different var genes of which only one has been believed to be transcribed per cell at a time during the blood stage of the infection. How such mutually exclusive regulation of var gene transcription is achieved is unclear, as is the identification of individual var genes or sub-groups of var genes associated with different receptors and the consequence of differential binding on the clinical outcome of P. falciparum infections. Recently, the mutually exclusive transcription paradigm has been called into doubt by transcription assays based on individual P. falciparum transcript identification in single infected erythrocytic cells using RNA fluorescent in situ hybridization (FISH) analysis of var gene transcription by the parasite in individual nuclei of P. falciparum IE1.
Here, we present a detailed protocol for carrying out the RNA-FISH methodology for analysis of var gene transcription in single-nuclei of P. falciparum infected human erythrocytes. The method is based on the use of digoxigenin- and biotin- labeled antisense RNA probes using the TSA Plus Fluorescence Palette System2 (Perkin Elmer), microscopic analyses and freshly selected P. falciparum IE. The in situ hybridization method can be used to monitor transcription and regulation of a variety of genes expressed during the different stages of the P. falciparum life cycle and is adaptable to other malaria parasite species and other organisms and cell types.

Analysis of Single-cell Gene Transcription by RNA Fluorescent In Situ Hybridization FISH

Fluorescent in situ hybridization (FISH) to identify mRNA transcripts in individual cells allows analysis of polygenic activity such as the simultaneous transcription of more than one member of the var multigene family in Plasmodium falciparum infected erythrocytes 1. The technique is adaptable and can be used on different types of genes, cells and organisms.

Analisi di Single-cell trascrizione del gene per l&#39;RNA fluorescente<em&gt; In Situ</em&gt; Ibridazione (FISH)

Adhesion of Plasmodium falciparum infected erythrocytes (IE) to human endothelial receptors during malaria infections is mediated by expression of PfEMP1 ...

Analysis of Global RNA Synthesis at the Single Cell Level following Hypoxia

Hypoxia or lowering of the oxygen availability is involved in many physiological and pathological processes. At the molecular level, cells initiate a particular transcriptional program in order to mount an appropriate and coordinated cellular response. The cell possesses several oxygen sensor enzymes that require molecular oxygen as cofactor for their activity. These range from prolyl-hydroxylases to histone demethylases. The majority of studies analyzing cellular responses to hypoxia are based on cellular populations and average studies, and as such single cell analysis of hypoxic cells are seldom performed. Here we describe a method of analysis of global RNA synthesis at the single cell level in hypoxia by using Click-iT RNA imaging kits in an oxygen controlled workstation, followed by microscopy analysis and quantification.&nbsp; Using cancer cells exposed to hypoxia for different lengths of time, RNA is labeled and measured in each cell. This analysis allows the visualization of temporal and cell-to-cell changes in global RNA synthesis following hypoxic stress.

We describe a technique for analysis of global RNA synthesis in hypoxia using imaging. Click-chemistry labeling of RNA has not previously been performed under hypoxia and allows visualization of global RNA changes at the single cell level. This approach complements the existing averaged RNA techniques, allowing direct visualization of cell-to-cell changes in global RNA synthesis.

Analisi globale di RNA Sintesi a livello di singola cellula seguente ipossia

Hypoxia or lowering of the oxygen availability is involved in many physiological and pathological processes. At the molecular level, cells initiate a ...

Single-cell Microfluidic Analysis of Bacillus subtilis

Microfluidic technology overcomes many of the limitations to traditional analytical methods in microbiology. Unlike bulk-culture methods, it offers single-cell resolution and long observation times spanning hundreds of generations; unlike agarose pad-based microscopy, it has uniform growth conditions that can be tightly controlled. Because the continuous flow of growth medium isolates the cells in a microfluidic device from unpredictable variations in the local chemical environment caused by cell growth and metabolism, authentic changes in gene expression and cell growth in response to specific stimuli can be more confidently observed. Bacillus subtilis is used here as a model bacterial species to demonstrate a &#34;mother machine&#34;-type method for cellular analysis. We show how to construct and plumb a microfluidic device, load it with cells, initiate microscopic imaging, and expose cells to a stimulus by switching from one growth medium to another. A stress-responsive reporter is used as an example to reveal the type of data that may be obtained by this method. We also briefly discuss further applications of this method for other types of experiments, such as analysis of bacterial sporulation.

Single-cell Microfluidic Analysis of Bacillus subtilis

We present a method for the microfluidic analysis of individual bacterial cell lineages using Bacillus subtilis as an example. The method overcomes shortcomings of traditional analytical methods in microbiology by allowing observation of hundreds of cell generations under tightly controllable and uniform growth conditions.

Analisi Microfluidic unicellulare del Bacillus subtilis

Microfluidic technology overcomes many of the limitations to traditional analytical methods in microbiology. Unlike bulk-culture methods, it offers ...

Analysis of Beta-cell Function Using Single-cell Resolution Calcium Imaging in Zebrafish Islets

Pancreatic beta-cells respond to increasing blood glucose concentrations by secreting the hormone insulin. The dysfunction of beta-cells leads to hyperglycemia and severe, life-threatening consequences. Understanding how the beta-cells operate under physiological conditions and what genetic and environmental factors might cause their dysfunction could lead to better treatment options for diabetic patients. The ability to measure calcium levels in beta-cells serves as an important indicator of beta-cell function, as the influx of calcium ions triggers insulin release. Here we describe a protocol for monitoring the glucose-stimulated calcium influx in zebrafish beta-cells by using GCaMP6s, a genetically encoded sensor of calcium. The method allows monitoring the intracellular calcium dynamics with single-cell resolution in ex vivo mounted islets. The glucose-responsiveness of beta-cells within the same islet can be captured simultaneously under different glucose concentrations, which suggests the presence of functional heterogeneity among zebrafish beta-cells. Furthermore, the technique provides high temporal and spatial resolution, which reveals the oscillatory nature of the calcium influx upon glucose stimulation. Our approach opens the doors to use the zebrafish as a model to investigate the contribution of genetic and environmental factors to beta-cell function and dysfunction.

Beta-cell functionality is important for blood-glucose homeostasis, which is evaluated at single-cell resolution using a genetically encoded reporter for calcium influx.

Analisi della funzione Beta-cellulare usando la formazione immagine del calcio cella singola risoluzione in Zebrafish isolotti

Pancreatic beta-cells respond to increasing blood glucose concentrations by secreting the hormone insulin. The dysfunction of beta-cells leads to ...

Single-Cell Resolution Three-Dimensional Imaging of Intact Organoids

Organoid technology, in vitro 3D culturing of miniature tissue, has opened a new experimental window for cellular processes that govern organ development and function as well as disease. Fluorescence microscopy has played a major role in characterizing their cellular composition in detail and demonstrating their similarity to the tissue they originate from. In this article, we present a comprehensive protocol for high-resolution 3D imaging of whole organoids upon immunofluorescent labeling. This method is widely applicable for imaging of organoids differing in origin, size and shape. Thus far we have applied the method to airway, colon, kidney, and liver organoids derived from healthy human tissue, as well as human breast tumor organoids and mouse mammary gland organoids. We use an optical clearing agent, FUnGI, which enables the acquisition of whole 3D organoids with the opportunity for single-cell quantification of markers. This three-day protocol from organoid harvesting to image analysis is optimized for 3D imaging using confocal microscopy.

The entire 3D structure and cellular content of organoids, as well as their phenotypic resemblance to the original tissue can be captured using the single-cell resolution 3D imaging protocol described here. This protocol can be applied to a wide range of organoids varying in origin, size and shape.

Risoluzione a una cellula di immagini tridimensionali di organoidi intatti

Organoid technology, in vitro 3D culturing of miniature tissue, has opened a new experimental window for cellular processes that govern organ development ...

Real-Time Detection of Reactive Oxygen Species Production in Immune Response in Rice with a Chemiluminescence Assay

Reactive oxygen species (ROS) play vital roles in a variety of biological processes, including the sensing of abiotic and biotic stresses. Upon pathogen infection or challenge with pathogen-associated chemicals (pathogen-associated molecular patterns [PAMPs]), an array of immune responses, including a ROS burst, are quickly induced in plants, which is called PAMP-triggered immunity (PTI). A ROS burst is a hallmark PTI response, which is catalyzed by a group of plasma membrane-localized NADPH oxidases-the RBOH family proteins. The vast majority of ROS comprise hydrogen peroxide (H2O2), which can be easily and steadily detected by a luminol-based chemiluminescence method. Chemiluminescence is a photon-producing reaction in which luminol, or its derivative (such as L-012), undergoes a redox reaction with ROS under the action of a catalyst. This paper describes an optimized L-012-based chemiluminescence method to detect apoplast ROS production in real-time upon PAMP elicitation in rice tissues. The method is easy, steady, standardized, and highly reproducible under firmly controlled conditions.

Here, we describe a method for the real-time detection of apoplastic reactive oxygen species (ROS) production in rice tissues in pathogen-associated molecular pattern-triggered immune response. This method is simple, standardized, and generates highly reproducible results under controlled conditions.

Rilevamento in tempo reale della produzione di specie reattive dell'ossigeno nella risposta immunitaria nel riso con un saggio di chemiluminescenza

Reactive oxygen species (ROS) play vital roles in a variety of biological processes, including the sensing of abiotic and biotic stresses. Upon pathogen ...

Single-Cell Proteomics Preparation for Mass Spectrometry Analysis Using Freeze-Heat Lysis and an Isobaric Carrier

Single-cell proteomics analysis requires sensitive, quantitatively accurate, widely accessible, and robust methods. To meet these requirements, the Single-Cell ProtEomics (SCoPE2) protocol was developed as a second-generation method for quantifying hundreds to thousands of proteins from limited samples, down to the level of a single cell. Experiments using this method have achieved quantifying over 3,000 proteins across 1,500 single mammalian cells (500-1,000 proteins per cell) in 10 days of mass spectrometer instrument time. SCoPE2 leverages a freeze-heat cycle for cell lysis, obviating the need for clean-up of single cells and consequently reducing sample losses, while expediting sample preparation and simplifying its automation. Additionally, the method uses an isobaric carrier, which aids protein identification and reduces sample losses.
This video protocol provides detailed guidance to enable the adoption of automated single-cell protein analysis using only equipment and reagents that are widely accessible. We demonstrate critical steps in the procedure of preparing single cells for proteomic analysis, from harvesting up to injection to liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Additionally, viewers are guided through the principles of experimental design with the isobaric carrier, quality control for both isobaric carrier and single-cell preparations, and representative results with a discussion of limitations of the approach.

In this protocol, we describe how to prepare mammalian cells for single-cell proteomics analysis via mass spectrometry using commercially available reagents and equipment, with options for both manual and automatic pipetting.

Preparazione di proteomica a cella singola per analisi di spettrometria di massa mediante lisi a calore freddo e un vettore isobarico

Single-cell proteomics analysis requires sensitive, quantitatively accurate, widely accessible, and robust methods. To meet these requirements, the ...

Microiniezione cella singola per l'analisi cellulare comunicazione

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