Questo lavoro è stato finanziato dalla Yale School of Medicine e Salute Child Research Award da Charles Hood Foundation.

1. Riprogrammazione da Retrovirus Esprimere Fattori Riprogrammazione <ol><li> Fibroblasti umani vengono coltivate in mezzo di fibroblasti (10% FBS in DMEM con Pen / Strep). </li><li> Un giorno prima dell&#39;infezione, piastra 1x10 5 fibroblasti umani in un pozzetto di una piastra da 6 pozzetti. </li><li> Aspirare il terreno per eliminare le cellule morte e aggiungere 2 ml di terreno di fibroblasti fresco. Aggiungere protammina solfato ad una concentrazione finale di 5 pg / ml. </li><li> Cautela aggiungere la quantità appropriata di ciascun GFP-esprime virus corrispondente ad una molteplicità di infezione (MOI) 5 5. </li><li> Un giorno dopo l&#39;infezione, rimuovere il supernatante virale, lavare tre volte con 2 ml di PBS, quindi aggiungere due medie fibroblasti ml. </li><li> Tre giorni dopo l&#39;infezione, controllare la fluorescenza GFP e riempire il pozzo con 2 ml di terreno di fibroblasti. </li><li> Quattro giorni dopo l&#39;infezione, la piastra 1x10 4 / cm 2 di fibroblasti embrionali di topo irradiati (MEF) in cellule di alimentazione di fibroblasti su un mezzo10-cm Petri rivestito con 0,1% di gelatina. Incubare a 37 ° C per una notte. </li><li> Cinque giorni dopo l&#39;infezione, staccare infettati fibroblasti umani con 1 ml di 0,05% typsin / EDTA per 5 minuti a 37 ° C, e centrifugare per 5 minuti a 200 g. Aspirare il mezzo e risospendere le cellule con 10 ml di mezzo fibroblasti. Trasferire le cellule in un pre-rivestito 10-centimetri piastra. </li><li> Dopo 24 ore, sostituire il mezzo con il mezzo hESC cultura (20% Knock-Out sostituzione siero, DMEM/F12, 0,1 ml di aminoacidi non essenziali, 4 ng / ml bFGF, Pen / Strep / glutammato, beta-merceptoethanol). Cambia il mezzo di tutti i giorni. ESC-colonie, come inizierà ad apparire di giorno 20-27 dopo l&#39;infezione. </li></ol> 2. Isolamento ed espansione di iPSCs <ol><li> Sotto un microscopio a fluorescenza, verificare l&#39;assenza di fluorescenza GFP in una colonia che mostra una morfologia simile a hESC. </li><li> Usando una pipetta 10 pl, raccogliere le singole colonie IPSC e inserirli in un pozzetto di una gelatina e MEF-CoATed 12-pozzetti e integrato con media hESC. Cambiare media giornaliera. </li><li> Per passaging, lavare la piastra con 1 ml di DMEM/F12, quindi aggiungere 0,5 ml di collagenasi, e incubare per 10 minuti a 37 ° C. </li><li> Lavare le cellule due volte con DMEM/F12. </li><li> Aggiungere 2 ml di terreno fresco hESC. Utilizzando un sollevatore cella, rompere le colonie in piccoli pezzi e staccare le cellule rimanenti dalla piastra. </li><li> Trasferire i pezzi di colonie risospeso in un pozzetto di una gelatina e MEF rivestita piastra da 6 pozzetti. </li></ol> 3. Analisi Immunofluorescenza di marcatori pluripotenti <ol><li> Lavare le cellule tre volte con PBS e fissare con 4% paraformaldeide per 20 minuti a temperatura ambiente. </li><li> Lavare delicatamente le cellule tre volte con PBS e permeabile con 0,2% Triton X-100 in PBS per 30 min. </li><li> Blocco legame non specifico incubando le cellule con 3% BSA in PBS per due ore. </li><li> Incubare le cellule con anticorpo primario per una notte a 4 ° C. </li> &lt;li&gt; Lavare le cellule tre volte con PBS e incubare le cellule con anticorpo secondario specifico per un&#39;ora a temperatura ambiente, schermatura dalla luce. </li><li> Lavare le cellule tre volte con PBS e add DAPI durante l&#39;ultimo lavaggio seguito da incubazione a temperatura ambiente per 5 minuti. </li><li> Rilevare la colorazione con un microscopio a fluorescenza. </li></ol> 4. Quantitativa Real-time PCR per i marker pluripotenti <ol><li> Isolare RNA totale dalle iPSCs umane derivate da fibroblasti umani usando il kit RNeasy Qiagen. </li><li> Sintetizzare il primo filamento cDNA utilizzando trascrittasi inversa SuperScript II. </li><li> Eseguire qPCR per individuare i geni pluripotenziali usando i primer riportati in precedenza. 6 </li></ol> 5. Risultati rappresentativi <ol><li> Cambiamento morfologico durante la riprogrammazione Noi fibroblasti umani infettati BJ1 e Detroit 551 con un cocktail di retrovirus che trasportano Oct4, Sox2, Klf4 e MYC,e sono stati in grado di rilevare i cambiamenti morfologici durante riprogrammazione (Figura 1). Ventun giorni dopo l&#39;infezione, riconosciamo piccole colonie IPSC dalla loro hESC-come morfologia. Inoltre, riconosciamo iPSCs dalla fluorescenza GFP. Le cellule staminali pluripotenti, come CES e iPSCs, esprimono il macchinario molecolare di reprimere l&#39;espressione genica provirale 7-9. Il nostro unico vettore retrovirale esprime GFP insieme riprogrammazione geni LTR retrovirale. Così, le cellule esprimenti GFP continuo sono considerati per esprimere transgeni senza silenziamento genico provirale. Fedelmente riprogrammati colonie IPSC che acquisiscono la rete pluripotenza molecolare dimostrare l&#39;assenza di espressione di GFP (Figura 2) 10. </li><li> Caratterizzazione della pluripotenza delle iPSCs umani Abbiamo analizzato le colonie derivate da Detroit-551 fibroblasti via immunoistochimica con Tra-1-81, Tra-1-60, SSEA-4, SSE-3, e gli anticorpi OCT4 Nanog ( <strong&gt; Tabella 2). IPSCs successo riprogrammati esprimere tutti questi marcatori (Figura 3A). Abbiamo anche analizzato espressione genica tramite RT-PCR quantitativa analisi. Abbiamo osservato che l&#39;espressione di Oct4, Sox2, Klf4, MYC e Nanog era significativamente maggiore rispetto alle cellule di fibroblasti dei genitori, ma commisurata a quella di hESC H9 (Figura 3B). </li></ol><img alt="Figura 1" src="/files/ftp_upload/3804/3804fig1.jpg" /> Figura 1. Cambiamenti morfologici di fibroblasti umani infettati da retrovirus. (AD) progressivo cambiamento morfologico nelle colonie da Detroit-551 fibroblasti infettati con i fattori di riprogrammazione. Giorno 5 (A), Giorno 10 (B), Giorno 14 (C), giorno 21 (D). Le cellule mostrano la hESC-come morfologia dopo 21 giorni. <img alt="Figura 2" src="/files/ftp_upload/3804/3804fig2.jpg" /> Figura 2. Rappresentante espressione fluorescente GFP in cellule in fase di riprogrammazione. </strong&gt; BJ e Detroit 551 fibroblasti sono state infettate con retrovirus che esprime quattro fattori di riprogrammazione 4, e incubate in un mezzo hESC per quattro settimane. Fibroblasti BJ (A, B) e Detroit 551 (C, D) mostrano simili morfologica. Dal giorno 21, colonie GFP negativi cominciano a formarsi, che rappresentano le iPSCs buona fede 10. (E, F) mostrano trasformato Detroit 551 cellule che non hanno subito corretta riprogrammazione. (A, C, E) colonie sotto vista a contrasto di fase. (B, D) correttamente riprogrammato cellule che mostrano il silenziamento GFP. (F) espressione GFP luminoso da colonia trasformata. <img alt="Figura 3" src="/files/ftp_upload/3804/3804fig3.jpg" /> Figura 3. Caratterizzazione delle cellule staminali pluripotenti indotte umane. (A) 551-umane iPS-K1 colonie di cellule esprimono marcatori comuni alle cellule pluripotenti. Colorazione DAPI indica il contenuto totale delle cellule per campo. (B) quantitativa real time-PCR (RT-qPCR) per l&#39;espressione di Oct4, Sox2, Klf4, MYC in f genitoriibroblast e 551-IPS-K1 iPSCs e H9 cellule staminali embrionali umane (hESC). I dati sono stati normalizzati contro la β-actina gene housekeeping e tracciati rispetto al livello di espressione nelle cellule di fibroblasti parentali 4.

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<p class="jove_content"&gt; Non abbiamo nulla da rivelare.</p

Espressione di quattro fattori di trascrizione riprogramma i fibroblasti umani a iPSCs. Molti tentativi sono stati fatti per generare iPSCs umani utilizzando non-integrazione o non-genetica approcci per generare iPSCs clinicamente sicuro. Finora, questi metodi presentano efficienza estremamente bassa e richiedono ulteriore ottimizzazione per migliorare la riproducibilità 11-14. Metodi Retro-o lentivirali sono facilmente utilizzati per ricavare e applicare iPSCs per l&#39;uomo in modelli di malattia ...

<table border="1">
	<tbody>
		<tr>
			<td>Name</td>
			<td>Concentration</td>
			<td>Company</td>
			<td>Catalogue Number</td>
		</tr>
		<tr>
			<td colspan="4">hESC medium</td>
		</tr>
		<tr>
			<td>DMEM/F12</td>
			<td>80%</td>
			<td>Invitrogen</td>
			<td>11330057</td>
		</tr>
		<tr>
			<td>Knockout Serum Replacer</td>
			<td>20%</td>
			<td>Invitrogen</td>
			<td>10828-028</td>
		</tr>
		<tr>
			<td>L-Glutamine (200 mM)</td>
			<td>2 mM</td>
			<td>Invitrogen</td>
			<td>25030081</td>
		</tr>
		<tr>
			<td>Nonessential Amino Acids (10 mM)</td>
			<td>0.1 mM</td>
			<td>Invitrogen</td>
			<td>11140050</td>
		</tr>
		<tr>
			<td>&beta;-Mercaptoethanol (14.3 M) or MTG</td>
			<td>0.1 mM</td>
			<td>Invitrogen</td>
			<td>M-6250</td>
		</tr>
		<tr>
			<td>bFGF-2 10 &mu;g/ml</td>
			<td>4 ng/ml</td>
			<td>GIBCO/BRL</td>
			<td>GF003AF</td>
		</tr>
		<tr>
			<td>Penicillin/Streptomycin</td>
			<td>1%</td>
			<td>Millipore</td>
			<td>15140-122</td>
		</tr>
		<tr>
			<td colspan="4">Fiboblasts Medium</td>
		</tr>
		<tr>
			<td>DMEM</td>
			<td>90%</td>
			<td>Invitrogen</td>
			<td>11965118</td>
		</tr>
		<tr>
			<td>FBS</td>
			<td>10%</td>
			<td>Invitrogen</td>
			<td>10407028</td>
		</tr>
		<tr>
			<td>Penicillin/Streptomycin</td>
			<td>1%</td>
			<td>Millipore</td>
			<td>15140-122</td>
		</tr>
	</tbody>
</table>
Table 1. Culture Medium
<table border="1">
	<tbody>
		<tr>
			<td>Name</td>
			<td>Concentration</td>
			<td>Company</td>
			<td>Catalogue Number</td>
		</tr>
		<tr>
			<td colspan="4">Antibodies</td>
		</tr>
		<tr>
			<td>OCT4</td>
			<td>1:500</td>
			<td>Abcam</td>
			<td>Ab19857</td>
		</tr>
		<tr>
			<td>SSEA3</td>
			<td>1:100</td>
			<td>Milipore</td>
			<td>MAB4303</td>
		</tr>
		<tr>
			<td>SSEA4</td>
			<td>1:100</td>
			<td>BD Biosciences</td>
			<td>BD560218</td>
		</tr>
		<tr>
			<td>Tra-1-81</td>
			<td>1:100</td>
			<td>BD Biosciences</td>
			<td>BD560173</td>
		</tr>
		<tr>
			<td>Tra-1-60</td>
			<td>1:100</td>
			<td>BD Biosciences</td>
			<td>BD560174</td>
		</tr>
		<tr>
			<td>NANOG</td>
			<td>1:500</td>
			<td>Abcam</td>
			<td>Ab21624</td>
		</tr>
		<tr>
			<td>Alexa-Flur 488</td>
			<td>1:1000</td>
			<td>Invitrogen</td>
			<td>A11008</td>
		</tr>
		<tr>
			<td>Alexa-Flur 555</td>
			<td>1:1000</td>
			<td>Invitrogen</td>
			<td>A21422</td>
		</tr>
		<tr>
			<td>DAPI</td>
			<td>1:5000</td>
			<td>Invitrogen</td>
			<td>D1306</td>
		</tr>
		<tr>
			<td colspan="4">Plasmids</td>
		</tr>
		<tr>
			<td>pMIG-OCT4</td>
			<td>&nbsp;</td>
			<td>Addgene</td>
			<td>17225</td>
		</tr>
		<tr>
			<td>pMIG-SOX2</td>
			<td>&nbsp;</td>
			<td>Addgene</td>
			<td>17226</td>
		</tr>
		<tr>
			<td>pMIG-KLF4</td>
			<td>&nbsp;</td>
			<td>Addgene</td>
			<td>17227</td>
		</tr>
		<tr>
			<td>pMIG-MYC</td>
			<td>&nbsp;</td>
			<td>Addgene</td>
			<td>18119</td>
		</tr>
		<tr>
			<td colspan="4">Other Materials</td>
		</tr>
		<tr>
			<td>Collagenase type IV</td>
			<td>1mg/ml</td>
			<td>Invitrogen</td>
			<td>17104019</td>
		</tr>
		<tr>
			<td>Gelatin, Porcine</td>
			<td>0.1%</td>
			<td>Sigma</td>
			<td>G 1890</td>
		</tr>
		<tr>
			<td>Triton</td>
			<td>0.2%</td>
			<td>Sigma</td>
			<td>X100-500ML</td>
		</tr>
		<tr>
			<td>Paraformaldehyde</td>
			<td>4%</td>
			<td>Sigma</td>
			<td>47608</td>
		</tr>
		<tr>
			<td>BSA</td>
			<td>3%</td>
			<td>American Bioanalytical</td>
			<td>AB01800</td>
		</tr>
		<tr>
			<td>MEF feeder cells</td>
			<td>&nbsp;</td>
			<td>Millipore</td>
			<td>PMEF-N</td>
		</tr>
		<tr>
			<td>Cell Lifter</td>
			<td>&nbsp;</td>
			<td>Corning</td>
			<td>3008</td>
		</tr>
		<tr>
			<td colspan="4">Equipment</td>
		</tr>
		<tr>
			<td colspan="4">Fluorescent microscopy: inverted microscope with GFP filter</td>
		</tr>
	</tbody>
</table>
Table 2. Reagents and equipment.

reprogramming human somatic cells into induced pluripotent stem cells (ipscs) using retroviral vector with gfp

Cellule staminali embrionali umane (hESC) sono pluripotenti e una fonte inestimabile per cellulari in vitro modelli di malattia e della medicina rigenerativa 1. E &#39;stato precedentemente dimostrato che cellule somatiche umane può essere riprogrammato per pluripotenza dall&#39;espressione ectopica di quattro fattori di trascrizione (Oct4, Sox2, Klf4 e Myc) e diventare cellule staminali pluripotenti indotte (iPSCs) 2-4. Come hESC, iPSCs umani sono pluripotenti e una fonte potenziale di cellule autologhe. Qui descriviamo il protocollo per riprogrammare cellule di fibroblasti umani con i quattro fattori di riprogrammazione clonati in GFP-retrovirale contenente backbone 4. Utilizzando il seguente protocollo, generiamo iPSCs umani in 3-4 settimane sotto condizione umana della cultura ESC. Umani colonie IPSC assomigliano hESC nella morfologia e visualizzare la perdita di fluorescenza GFP come risultato di silenziamento del transgene retrovirale. colonie IPSC isolato meccanicamente con un microsco fluorescenzape si comportano in modo simile a come hESC. In queste cellule, si rileva l&#39;espressione di geni multipli pluripotenziali e marcatori di superficie.

Watch this Scientific Journal Video about Reprogramming Human Somatic Cells into Induced Pluripotent Stem Cells iPSCs Using Retroviral Vector with GFP at JoVE.com

Reprogramming Human Somatic Cells into Induced Pluripotent Stem Cells iPSCs Using Retroviral Vector with GFP

Un metodo per generare umani cellule staminali pluripotenti indotte (iPSCs) tramite retrovirus-mediata espressione ectopica di Oct4, Sox2, Klf4 e MYC è descritto. Un modo pratico per identificare umani IPSC colonie sulla base di GFP è anche discusso.

Riprogrammare cellule somatiche umane in cellule staminali pluripotenti indotte (iPSCs) Utilizzo vettore retrovirale con GFP

Human embryonic stem cells (hESCs) are pluripotent and an invaluable cellular sources for in vitro disease modeling and regenerative medicine1. It has ...

reprogramming-human-somatic-cells-into-induced-pluripotent-stem-cells

Research

JoVE Journal

Biology

Reprogramming Human Somatic Cells into Induced Pluripotent Stem Cells (iPSCs) Using Retroviral Vector with GFP

20.3K Views.  Yale School of Medicine. Un metodo per generare umani cellule staminali pluripotenti indotte (iPSCs) tramite retrovirus-mediata espressione ectopica di Oct4, Sox2, Klf4 e MYC è descritto. Un modo pratico per identificare umani IPSC colonie sulla base di GFP è anche discusso.

Video: Reprogramming Human Somatic Cells into Induced Pluripotent Stem Cells iPSCs Using Retroviral Vector with GFP

Generation of Induced Pluripotent Stem Cells by Reprogramming Mouse Embryonic Fibroblasts with a Four Transcription Factor, Doxycycline Inducible Lentiviral Transduction System

Using a defined set of transcription factors and cell culture conditions, Yamanaka and colleagues demonstrated that retrovirus-mediated delivery and expression of Oct4, Sox2, c-Myc, and Klf4 is capable of inducing pluripotency in mouse fibroblasts.1 Subsequent reports have demonstrated the utility of the doxycycline (DOX) inducible lentiviral delivery system for the generation of both primary and secondary iPS cells from a variety of other adult mouse somatic cell types.2,3
Induced pluripotent stem (iPS) cells are similar to embryonic stem (ES) cells in morphology, proliferation and ability to induce teratoma formation. Both types of cell can be used as the pluripotent starting material for the generation of differentiated cells or tissues in regenerative medicine.4-6 iPS cells also have a distinct advantage over ES cells as they exhibit key properties of ES cells without the ethical dilemma of embryo destruction.
Here we demonstrate the protocol for reprogramming mouse embryonic fibroblast (MEF) cells with the Stemgent DOX Inducible Mouse TF Lentivirus Set. We also demonstrate that the Stemgent DOX Inducible Mouse TF Lentivirus Set is capable of expressing each of the four transcription factors upon transduction into MEFs thereby inducing a pluripotent stem cell state that displays the pluripotency markers characteristic of ES cells.

The Stemgent Dox Inducible Mouse TF Lentivirus Set can reprogram mouse embryonic fibroblasts (MEFs) to induced pluripotent stem (iPS) cells. Here we demonstrate the protocol for DOX-inducible expression of mouse reprogramming transcription factors Oct4, Sox2, Klf4 and c-Myc to generate iPS colonies that express common mES pluripotency markers.

Generazione di cellule staminali pluripotenti indotte da Riprogrammazione fibroblasti embrionali di topo con un fattore quattro trascrizione, Doxiciclina inducibile lentivirali sistema di trasduzione

Using a defined set of transcription factors and cell culture conditions, Yamanaka and colleagues demonstrated that retrovirus-mediated delivery and ...

Ricerca

Biologia

Generation of Induced Pluripotent Stem Cells by Reprogramming Human Fibroblasts with the Stemgent Human TF Lentivirus Set

In 2006, Yamanaka and colleagues first demonstrated that retrovirus-mediated delivery and expression of Oct4, Sox2, c-Myc and Klf4 is capable of inducing the pluripotent state in mouse fibroblasts.1 The same group also reported the successful reprogramming of human somatic cells into induced pluripotent stem (iPS) cells using human versions of the same transcription factors delivered by retroviral vectors.2 Additionally, James Thomson et al. reported that the lentivirus-mediated co-expression of another set of factors (Oct4, Sox2, Nanog and Lin28) was capable of reprogramming human somatic cells into iPS cells.3
iPS cells are similar to ES cells in morphology, proliferation and the ability to differentiate into all tissue types of the body. Human iPS cells have a distinct advantage over ES cells as they exhibit key properties of ES cells without the ethical dilemma of embryo destruction. The generation of patient-specific iPS cells circumvents an important roadblock to personalized regenerative medicine therapies by eliminating the potential for immune rejection of non-autologous transplanted cells.
Here we demonstrate the protocol for reprogramming human fibroblast cells using the Stemgent Human TF Lentivirus Set. We also show that cells reprogrammed with this set begin to show iPS morphology four days post-transduction. Using the Stemolecule Y27632, we selected for iPS cells and observed correct morphology after three sequential rounds of colony picking and passaging. We also demonstrate that after reprogramming cells displayed the pluripotency marker AP, surface markers TRA-1-81, TRA-1-60, SSEA-4, and SSEA-3, and nuclear markers Oct4, Sox2 and Nanog.

We demonstrate the protocol for the generation of induced pluripotent stem cells from human somatic cells using lentivirus-mediated delivery of the human factors Oct4, Sox2, Nanog, and Lin28. Pluripotency was confirmed by morphology and the presence of embryonic stem (ES) cell-specific markers.

Generazione di cellule staminali pluripotenti indotte da fibroblasti umani Riprogrammare con il Stemgent Lentivirus umani TF Set

In 2006, Yamanaka and colleagues first demonstrated that retrovirus-mediated delivery and expression of Oct4, Sox2, c-Myc and Klf4 is capable of inducing ...

Transfecting and Nucleofecting Human Induced Pluripotent Stem Cells

Genetic modification is continuing to be an essential tool in studying stem cell biology and in setting forth potential clinical applications of human embryonic stem cells (HESCs)1. While improvements in several gene delivery methods have been described2-9, transfection remains a capricious process for HESCs, and has not yet been reported in human induced pluripotent stem cells (iPSCs). In this video, we demonstrate how our lab routinely transfects and nucleofects human iPSCs using plasmid with an enhanced green fluorescence protein (eGFP) reporter. Human iPSCs are adapted and maintained as feeder-free cultures to eliminate the possibility of feeder cell transfection and to allow efficient selection of stable transgenic iPSC clones following transfection. For nucleofection, human iPSCs are pre-treated with ROCK inhibitor11, trypsinized into small clumps of cells, nucleofected and replated on feeders in feeder cell-conditioned medium to enhance cell recovery. Transgene-expressing human iPSCs can be obtained after 6 hours. Antibiotic selection is applied after 24 hours and stable transgenic lines appear within 1 week. Our protocol is robust and reproducible for human iPSC lines without altering pluripotency of these cells.

Despite recent advancements in genetic modification, transfection of human embryonic stem cells (HESCs) remains a capricious process. To our knowledge, systematic and efficient methods to transfect human induced pluripotent stem cells (iPSCs) have not been reported. Here, we describe robust protocols to efficiently transfect and nucleofect human iPSCs.

Trasfettando e Nucleofecting umani cellule staminali pluripotenti indotte

Genetic modification is continuing to be an essential tool in studying stem cell biology and in setting forth potential clinical applications of human ...

Preparation of Mouse Embryonic Fibroblast Cells Suitable for Culturing Human Embryonic and Induced Pluripotent Stem Cells

In general, human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs)1 can be cultured under variable conditions. However, it is not easy to establish an effective system for culturing these cells. Since the culture conditions can influence gene expression that confers pluripotency in hESCs and hiPSCs, the optimization and standardization of the culture method is crucial.
The establishment of hESC lines was first described by using MEFs as feeder cells and fetal bovine serum (FBS)-containing culture medium2. Next, FBS was replaced with knockout serum replacement (KSR) and FGF2, which enhances proliferation of hESCs3. Finally, feeder-free culture systems enable culturing cells on Matrigel-coated plates in KSR-containing conditioned medium (medium conditioned by MEFs)4. Subsequently, hESCs culture conditions have moved towards feeder-free culture in chemically defined conditions5-7. Moreover, to avoid the potential contamination by pathogens and animal proteins culture methods using xeno-free components have been established8.
To obtain improved conditions mouse feeder cells have been replaced with human cell lines (e.g. fetal muscle and skin cells9, adult skin cells10, foreskin fibroblasts11-12, amniotic mesenchymal cells13). However, the efficiency of maintaining undifferentiated hESCs using human foreskin fibroblast-derived feeder layers is not as high as that from mouse feeder cells due to the lower level of secretion of Activin A14. Obviously, there is an evident difference in growth factor production by mouse and human feeder cells.
Analyses of the transcriptomes of mouse and human feeder cells revealed significant differences between supportive and non-supportive cells. Exogenous FGF2 is crucial for maintaining self-renewal of hESCs and hiPSCs, and has been identified as a key factor regulating the expression of Tgf&beta;1, Activin A and Gremlin (a BMP antagonist) in feeder cells. Activin A has been shown to induce the expression of OCT4, SOX2, and NANOG in hESCs15-16.
For long-term culture, hESCs and hiPSCs can be grown on mitotically inactivated MEFs or under feeder-free conditions in MEF-CM (MEF-Conditioned Medium) on Matrigel-coated plates to maintain their undifferentiated state. Success of both culture conditions fully depends on the quality of the feeder cells, since they directly affect the growth of hESCs.
Here, we present an optimized method for the isolation and culture of mouse embryonic fibroblasts (MEFs), preparation of conditioned medium (CM) and enzyme-linked immunosorbent assay (ELISA) to assess the levels of Activin A within the media.

The quality of mouse embryonic fibroblasts (MEFs) is dictated by the right strain of mouse such as CF-1. Pluripotency-supportive MEFs and conditioned media (CM) obtained from these should contain optimal concentrations of Activin A, Gremlin and Tgf&beta;1 needed for the Activin/Nodal and FGF pathways to co-operatively maintain self-renewal and pluripotency.

Preparazione di cellule di fibroblasti embrionali di topo adatto per colture di cellule pluripotenti umane embrionali e staminali indotta

In general, human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs)1 can be cultured under variable conditions. However, it ...

Generation of Human Induced Pluripotent Stem Cells from Peripheral Blood Using the STEMCCA Lentiviral Vector

Through the ectopic expression of four transcription factors, Oct4, Klf4, Sox2 and cMyc, human somatic cells can be converted to a pluripotent state, generating so-called induced pluripotent stem cells (iPSCs)1-4. Patient-specific iPSCs lack the ethical concerns that surround embryonic stem cells (ESCs) and would bypass possible immune rejection. Thus, iPSCs have attracted considerable attention for disease modeling studies, the screening of pharmacological compounds, and regenerative therapies5.
We have shown the generation of transgene-free human iPSCs from patients with different lung diseases using a single excisable polycistronic lentiviral Stem Cell Cassette (STEMCCA) encoding the Yamanaka factors6. These iPSC lines were generated from skin fibroblasts, the most common cell type used for reprogramming. Normally, obtaining fibroblasts requires a skin punch biopsy followed by expansion of the cells in culture for a few passages. Importantly, a number of groups have reported the reprogramming of human peripheral blood cells into iPSCs7-9. In one study, a Tet inducible version of the STEMCCA vector was employed9, which required the blood cells to be simultaneously infected with a constitutively active lentivirus encoding the reverse tetracycline transactivator. In contrast to fibroblasts, peripheral blood cells can be collected via minimally invasive procedures, greatly reducing the discomfort and distress of the patient. A simple and effective protocol for reprogramming blood cells using a constitutive single excisable vector may accelerate the application of iPSC technology by making it accessible to a broader research community. Furthermore, reprogramming of peripheral blood cells allows for the generation of iPSCs from individuals in which skin biopsies should be avoided (i.e. aberrant scarring) or due to pre-existing disease conditions preventing access to punch biopsies.
Here we demonstrate a protocol for the generation of human iPSCs from peripheral blood mononuclear cells (PBMCs) using a single floxed-excisable lentiviral vector constitutively expressing the 4 factors. Freshly collected or thawed PBMCs are expanded for 9 days as described10,11 in medium containing ascorbic acid, SCF, IGF-1, IL-3 and EPO before being transduced with the STEMCCA lentivirus. Cells are then plated onto MEFs and ESC-like colonies can be visualized two weeks after infection. Finally, selected clones are expanded and tested for the expression of the pluripotency markers SSEA-4, Tra-1-60 and Tra-1-81. This protocol is simple, robust and highly consistent, providing a reliable methodology for the generation of human iPSCs from readily accessible 4 ml of blood.

Here we show a simple and effective protocol for the generation of human iPSCs from 3-4 ml of peripheral blood using a single lentiviral reprogramming vector. Reprogramming of readily available blood cells promises to accelerate the utilization of iPSC technology by making it accessible to a broader research community.

Generazione di cellule pluripotenti indotte umane staminali da sangue periferico mediante il STEMCCA lentivirale Vector

Through the ectopic expression of four transcription factors, Oct4, Klf4, Sox2 and cMyc, human somatic cells can be converted to a pluripotent state, ...

In vivo Reprogramming of Adult Somatic Cells to Pluripotency by Overexpression of Yamanaka Factors

Induced pluripotent stem (iPS) cells that result from the reprogramming of somatic cells to a pluripotent state by forced expression of defined factors are offering new opportunities for regenerative medicine. Such clinical applications of iPS cells have been limited so far, mainly due to the poor efficiency of the existing reprogramming methodologies and the risk of the generated iPS cells to form tumors upon implantation.
We hypothesized that the reprogramming of somatic cells towards pluripotency could be achieved in vivo by gene transfer of reprogramming factors. In order to efficiently reprogram cells in vivo, high levels of the Yamanaka (OKSM) transcription factors need to be expressed at the target tissue. This can be achieved by using different viral or nonviral gene vectors depending on the target tissue. In this particular study, hydrodynamic tail-vein (HTV) injection of plasmid DNA was used to deliver the OKSM factors to mouse hepatocytes. This provided proof-of-evidence of in vivo reprogramming of adult, somatic cells towards a pluripotent state with high efficiency and fast kinetics. Furthermore no tumor or teratoma formation was observed in situ.
It can be concluded that reprogramming somatic cells in vivo may offer a potential approach to induce enhanced pluripotency rapidly, efficiently, and safely compared to in vitro performed protocols and can be applied to different tissue types in the future.

In vivo Reprogramming of Adult Somatic Cells to Pluripotency by Overexpression of Yamanaka Factors

This study demonstrates the reprogramming of somatic cells towards pluripotency in vivo without the generation of teratomas. We used hydrodynamic tail vein injection of plasmid DNA encoding the Yamanka factors to induce the in vivo reprogramming of adult hepatocytes into cells of enhanced pluripotency.

In vivo riprogrammazione di età somatiche celle a pluripotenza da iperespressione di fattori Yamanaka

Induced pluripotent stem (iPS) cells that result from the reprogramming of somatic cells to a pluripotent state by forced expression of defined factors ...

Efficient Generation Human Induced Pluripotent Stem Cells from Human Somatic Cells with Sendai-virus

A few years ago, the establishment of human induced pluripotent stem cells (iPSCs) ushered in a new era in biomedicine. Potential uses of human iPSCs include modeling pathogenesis of human genetic diseases, autologous cell therapy after gene correction, and personalized drug screening by providing a source of patient-specific and symptom relevant cells. However, there are several hurdles to overcome, such as eliminating the remaining reprogramming factor transgene expression after human iPSCs production. More importantly, residual transgene expression in undifferentiated human iPSCs could hamper proper differentiations and misguide the interpretation of disease-relevant in vitro phenotypes. With this reason, integration-free and/or transgene-free human iPSCs have been developed using several methods, such as adenovirus, the piggyBac system, minicircle vector, episomal vectors, direct protein delivery and synthesized mRNA. However, efficiency of reprogramming using integration-free methods is quite low in most cases.
Here, we present a method to isolate human iPSCs by using Sendai-virus (RNA virus) based reprogramming system. This reprogramming method shows consistent results and high efficiency in cost-effective manner.

Here, we present our established method to reprogram human somatic cells into transgene-free human iPSCs with Sendai virus, which shows consistent outcome and enhanced efficiency.

Efficiente generazione indotta umane pluripotenti cellule staminali da cellule somatiche umane con Sendai-virus

A few years ago, the establishment of human induced pluripotent stem cells (iPSCs) ushered in a new era in biomedicine. Potential uses of human iPSCs ...

Episomal Reprogramming of Dermal Fibroblasts to Generate Human-Induced Pluripotent Stem Cells (hiPSCs)

Episomal Reprogramming of Dermal Fibroblasts to Generate Human-Induced Pluripotent Stem Cells (HiPSCs)  

To begin, take a flask of cultured fibroblast cells, coat a 10-centimeter cell culture plate suitable for hiPSC culture with four milliliters of cold coating solution per plate, and incubate the plate for one hour at 37 degrees Celsius. Afterward, remove the media from the fibroblasts and wash them with four milliliters of pre-warmed PBS per flask. Aspirate the PBS and associate the fibroblasts with four milliliters of Trypsin-EDTA per flask by incubating for five to seven minutes at 37 degrees Celsius.Monitor cell detachment using a phase contrast microscope, and if needed, tap against the side of the flask to detach the cells from the plastic surface. Transfer the detached cells to a 50-milliliter conical tube and wash the empty flasks with six milliliters of pre-warmed fibroblast medium. Collect and pool the remaining cells in the conical tube.Then centrifuge the cells at 200 g for five minutes at 20 degrees Celsius. Aspirate the supernatant and re-suspend the cell pellet in three milliliters of fresh, pre-warmed PBS. Count the cells, transfer 1.5 times 10 to the sixth fibroblasts into a new conical tube and fill up with PBS to the five millimeter mark.Centrifuge the tube at 200 g for five minutes at 20 degrees Celsius. Discard the supernatant, re-suspend the cell pellet in five milliliters of electroporation medium, and centrifuge again. In the meantime, aspirate the coating solution from the coated 10-centimeter cell culture plate and add seven milliliters of pre-warmed fibroblast medium.At the end of the centrifugation, discard the supernatant and re-suspend the cell pellet in electroporation medium with a concentration of 1.5 times 10 to the sixth cells in 250 microliters. Transfer the 250 microliter cell suspension to an electroporation cuvette with a four millimeter gap distance. Next, prepare a plasma transfection mix by adding four micrograms of each plasmid to a total volume of 50 microliters of electroporation medium.Transfer the transfection mix to the cuvette, mix gently by flicking, and electroporate with one pulse at 280 volts. Finally, transfer 150 microliters of the electroporated fibroblasts to the prepared 10-centimeter cell culture plate. Agitate the plate thrice in all directions to distribute the cells, and incubate overnight.Fibroblasts present in a long, spindle-like phenotype, the size of 150 to 300 nanometers. After reprogramming, colonies with 50 micrometer small hiPSCs occur displaying distinct borders. The hiPSCs are distinguished by a high nuclei to body ratio and increased proliferation rate.

Riprogrammazione episomiale dei fibroblasti dermici per generare cellule staminali pluripotenti indotte dall'uomo (hiPSCs)

Generation and Maintenance of Primate Induced Pluripotent Stem Cells Derived from Urine

Cross-species approaches studying primate pluripotent stem cells and their derivatives are crucial to better understand the molecular and cellular mechanisms of disease, development, and evolution. To make primate induced pluripotent stem cells (iPSCs) more accessible, this paper presents a non-invasive method to generate human and non-human primate iPSCs from urine-derived cells, and their maintenance using a feeder-free culturing method.
The urine can be sampled from a non-sterile environment (e.g., the cage of the animal) and treated with a broad-spectrum antibiotic cocktail during primary cell culture to reduce contamination efficiently. After propagation of the urine-derived cells, iPSCs are generated by a modified transduction method of a commercially available Sendai virus vector system. First&#160;iPSC colonies may already be visible after 5 days, and can be picked after 10 days at the earliest. Routine clump passaging with enzyme-free dissociation buffer supports pluripotency of the generated iPSCs for more than 50 passages.

The present protocol describes a method to isolate, expand, and reprogram human and non-human primate urine-derived cells to induced pluripotent stem cells (iPSCs), as well as instructions for feeder-free maintenance of the newly generated iPSCs.

Generazione e mantenimento di cellule staminali pluripotenti indotte da primati derivate dall'urina

Cross-species approaches studying primate pluripotent stem cells and their derivatives are crucial to better understand the molecular and cellular ...

Caratterizzazione degli antigeni di superficie e capacità di proliferazione nelle MSC che guidano le hiPSC

Comparison of Two Representative Methods for Differentiation of Human Induced Pluripotent Stem Cells into Mesenchymal Stromal Cells

Mesenchymal stromal cells (MSCs) are adult pluripotent stem cells which have been widely used in regenerative medicine. As somatic tissue-derived MSCs are restricted by limited donation, quality variations, and biosafety, the past 10 years have seen a great rise in efforts to generate MSCs from human induced pluripotent stem cells (hiPSCs). Past and recent efforts in the differentiation of hiPSCs into MSCs have been centered around two culture methodologies: (1) the formation of embryoid bodies (EBs) and (2) the use of monolayer culture. This protocol describes these two representative methods in deriving MSC from hiPSCs. Each method presents its advantages and disadvantages, including time, cost, cell proliferation ability, the expression of MSC markers, and their capability of differentiation in vitro. This protocol demonstrates that both methods can derive mature and functional MSCs from hiPSCs. The monolayer method is characterized by lower cost, simpler operation, and easier osteogenic differentiation, while the EB method is characterized by lower time consumption.

Autore in primo piano: Progressi nelle iPSC e nella ricerca sulle malattie genetiche 

This protocol describes and compares two representative methods for differentiating hiPSCs into mesenchymal stromal cells (MSCs). The monolayer method is characterized by lower cost, simpler operation, and easier osteogenic differentiation. The embryoid bodies (EBs) method is characterized by lower time consumption.

Confronto di due metodi rappresentativi per la differenziazione di cellule staminali pluripotenti indotte umane in cellule stromali mesenchimali

Mesenchymal stromal cells (MSCs) are adult pluripotent stem cells which have been widely used in regenerative medicine. As somatic tissue-derived MSCs are ...