We wish to thank the following individuals: Drs. Tim Krohne and Eyal Banin (along with Dr. Mandy Lehmann and David Friedlander) for generous help developing the differentiation protocols. Dr. Felicitas Bucher provided assistance differentiating the RPE cells used in this study. We also acknowledge the National Eye Institute (NEI grants EY11254 and EY021416), California Institute for Regenerative Medicine (CIRM grant TR1-01219), and the Lowy Medical Research Institute (LMRI) for very generous funding for this project.

1. gerichteten Differenzierung von Stammzellen gewonnenen RPE Anmerkung: Alle Inkubationsschritte werden bei 37 ° C in 5% CO 2 durchgeführt <ol style="margin-left: 40px;"><li> Pflegen Sie die hES oder Hüfte Linien (täglich füttern) in Erhaltungsmedium (MM; Tabelle 1). Sobald die Leitungen ausreichende Standards der Qualitätskontrolle zu erreichen, halten sie auf einer Schicht von embryonalen Maus-Feeder-Zellen (MEFs) ausgesät mit einer Dichte von 250.000 / well eines Sechs-Well-Platte. Xeno freien Kulturen kann auch nach der von Tucker et al. 40 festgelegten Protokoll erzeugt werden. </li><li> Lassen Sie die Stammzellenkolonien zur Konfluenz erreichen. </li><li> Wechseln Sie in Differenzierungsmedium mit Nicotinamid (DM / NIC; Tabelle 1); Futter täglich. </li><li> Nach drei Wochen in der Kultur, die Differenzierung Medien wechseln mit Nicotinamid und entweder Activin-A oder IDE-1 (DM / NIC / AA oder DM / NIC / IDE1; Tabelle 1) zu RPE Differenzierung zu verbessern. </li&gt; <li> Nach fünf Wochen in der Kultur, wechseln Sie wieder in DM / NIC. Fütterungszeiten sind nicht mehr notwendig, nachdem die pH-Indikatoren in den Medien nicht mehr drehen, gelb den Tag nach der Fütterung. </li><li> Warten Sie, bis Inseln pigmentierten Zellen angezeigt werden, die groß genug sind, um geschnitten und entfernt werden (siehe Abbildungen 2D-F und 3A). </li></ol> 2. Isola pigmentierte Inseln <ol style="margin-left: 40px;"><li> Bestreichen Sie die Vertiefungen einer Platte mit 24 Vertiefungen mit einer Matrix, die den natürlichen Zellumgebung (Xeno-frei ist vorzuziehen) nachahmt. HINWEIS: Cornea Messer und scharfen, spitzen Pinzette sind sehr nützlich für die Kommissionierung. Das gesamte Blatt von differenzierten Zellen können zu lösen, während Kommissionierung. Vermeiden Sie dies, indem Sie vorsichtig arbeiten und zunächst Kommissionierung Kolonien in der Mitte der Schale. </li><li> Füllen so viele Vertiefungen der Platte mit 24 Vertiefungen mit Differenzierungsmedium (DM; Tabelle 1), je nach Bedarf. Diese Entscheidung wird von der Anzahl der pigmentierten Kolonien hängengesammelt. </li><li> In einer Zellkultur Kapuze mit einem Binokular, von Hand ausgeschnitten pigmentierte Inselchen. Hacken jedes Inselchen an der Unterseite der Originalplatte mit einem Skalpell in etwa 2-6 Stücke und ergreifen Sie die pigmentierte Teile mit scharfen Pinzette. </li><li> Übertragen Sie 1-2 pigmentierte Stücke in jedem 24-Loch. </li><li> Medien für 3-5 Tage nicht verändern, bis die Zellen haften, dann starten verändernden Medien drei Mal pro Woche. (Wenn sie nicht nach dieser Zeit halten, ist die Wahrscheinlichkeit gut, dass sie nie tun). </li><li> Erweitern Zellen für 3-4 Wochen in Differenzierungsmedium (DM; Tabelle 1) - Ein Bild einer typischen Kultur wird in 3B gezeigt. Die Zellen können auch die gesamte noch nicht füllen, sondern wartet länger scheint nicht zu helfen. Feed-Zellen dreimal pro Woche. </li><li> Nach ca. 3 Wochen, Trauben von weißen Zellen manuell entfernen in Klumpen ggf. mit scharfen Pinzette. Diesen Schritt nicht tun, wenn es notwendig ist - es ist leicht zu Verunreinigungen einzuführen. Es ist ideal,versuchen, reinster Populationen von RPE von den ursprünglichen pigmentierte Kolonien in Schritt 1.6 erhalten. </li></ol> 3. Passagieren Stammzellen gewonnenen RPE <ol style="margin-left: 40px;"><li> Lösen die Zellen mit 200 &amp; mgr; l mit einer Zelldissoziationslösung (vorzugsweise nicht Trypsin ein Reagens, inaktiviert durch Verdünnung ist bevorzugt werden) bei 37 ° C für 5-8 min, und inaktivieren es durch Verdünnen mit DM. Verwenden Sie ein 200 ul Pipette abzuwaschen alle Zellen und sie wieder zu suspendieren (Wenn der gewählte und nur wenige Zellen enthält, sollten Sie die Bündelung der Zellen, die aus zwei 24-Brunnen). </li><li> Zentrifuge (800 xg für 5 min), Überstand verwerfen, und resuspendieren in 3 ml DM-Medien. </li><li> Wiederplatte Zellen aus einem (oder zwei) 24-Vertiefungen in einer Matrix beschichtet mit 6 Vertiefungen in 3 ml DM pro Napf (1: 5 Expansion). </li><li> Erweitern für 1-2 Wochen, bis sich die Zellen ~ 90% konfluent; ein Bild der ausdifferenzierten reine Kultur ist in 3C gezeigt. </li><li> Trennen Sie die Zellen mit 1 ml Zell dissociation Lösung für ca. 5-8 Minuten bei 37 ° C, zu inaktivieren es durch Verdünnen mit DM, verwenden Sie 1000 ul Pipette abzuwaschen alle Zellen und Resuspendieren sie. </li><li> Spin down (800 xg für 5 min), Überstand verwerfen und Resuspension in 18 ml DM-Medien. </li><li> Wiederplatte Zellen von einer 6-well jeder in sechs Matrix beschichteten 6-wells in 3 ml DM pro Napf (1: 6 Expansion) oder einer beschichteten 75 cm 2 -Kolben (1: 7.5 Expansion). </li><li> Die Schritte 3,4-3,8 wie nötig, bis genügend Zellen erhalten werden. HINWEIS: Versuchen Sie so viele Kolonien wie möglich für die Expansion und nicht planen, die Kulturen über Passagierung zu verstärken, da jeder Durchgang induziert RPE Entdifferenzierung zu sammeln. </li></ol>

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None of the authors have any commercial disclosures to declare.

In diesem Manuskript wir einen Überblick über die Schritte, um eine große Anzahl von reinen iPS-RPE Kulturen effizient zu erzeugen. Wir haben bereits mit dieser gerichtet Differenzierung Protokoll mit Activin A, die wir iPS-RPE, die stark ähneln hRPE basierend auf Transkriptom, Proteomik, Metabolomik und Funktionalität zu generieren gezeigt, und dass sie zu verzögern Netzhautdegeneration, wenn in RCS Ratten implantiert 12,31,32 . Der Prozess der Erzeugung iPS-RPE ist zeitaufwendig, aber nicht mühsam <s...

The various cell types that occupy the retina are organized in a functional architecture. The photoreceptors in the back of the retina are responsible for converting light into electrical impulses through phototransduction. However, phototransduction cannot occur without the coordinated efforts of other neighboring cell types including Mueller glia and retinal pigment epithelium (RPE) cells. A monolayer of RPE cells partitions the sensory retina from the choriocapillaris, the primary blood supply for photoreceptors, and are ideally situated to control multiple functions important for photoreceptor homeostasis. In fact, the RPE and photoreceptors are so co-dependent they are widely considered to be one single functional unit. (For a review of all the diverse functions of the RPE see Strauss, 20051.) Death or dysfunction of retinal pigment epithelium cells can induce age-related macular degeneration (AMD), the leading cause of permanent vision loss in industrialized countries2-4. 
AMD is a multifactorial disease of RPE, photoreceptors, and the choroidal vasculature; risk factors are diverse and include combinations of environmental and genetic influences5,6. Treatments for AMD are very limited, but one promising potential therapy is RPE cell replacement7,8. While the outcomes have been mixed, the transplantation of RPE cells in AMD patients (and in other patients with retinal degeneration) and also in rodent models of retinal degeneration, has the potential to transiently prevent significant photoreceptor atrophy9-23. (The animal model commonly used for these studies are Royal College of Surgeons (RCS) rats, which harbor a mutation in the MerTK gene. This mutation renders RPE cells incapable of phagocytosing photoreceptor outer segments and promotes retinal degeneration24.) While the reported survival rates of implanted RPE in the subretinal space of RCS rats and mice vary greatly, there is potential for them to survive for several months or years9,10,12,20. 
RPE cells can be obtained in sufficient numbers for transplantation by deriving them from pluripotent stem cells9-14,25-28. Several independent groups have demonstrated that these cells function in similar ways to their somatic counterparts, and long term studies suggest that they are safe upon implantation in rat and mouse disease models9,10,12,14,19,20,25,29-32. The use of induced pluripotent stem cells instead of embryonic stem cells may be advantageous since ethical issues and immunological challenges associated with allogeneic RPE may be obviated33,34. Another exciting application for iPS technology is disease modeling35. The ability to interrogate large numbers of RPE cells derived from patients with RPE diseases could be invaluable for understanding their molecular bases. This type of study has been performed recently with Best disease patient RPE and could pave the way for similar studies of inherited maculopathies36. 
The derivation of RPE from stem cells is a relatively simple process and can be done entirely in xeno-free conditions. The simplest strategy is to derive monolayers of RPE cells spontaneously, however, the yield can be significantly improved using directed differentiation techniques. But these techniques involve the use of exogenous protein factors that can be expensive and often generated in bacteria or other non-human sources10,12,37. In our studies we followed an established protocol10 that utilizes nicotinamide and Activin A, a signaling factor that has been shown to be sufficient for RPE specification38. Here we will demonstrate that the small molecule IDE-1 can adequately replace Activin A, thus reducing costs and alleviating concerns associated with the use of recombinant proteins39. Additionally, we utilize xeno-free serum replacement, and we culture the differentiating RPE cells on a synthetic xeno-free substrate. RPE cells have been shown previously to differentiate very effectively using this approach40.
When differentiated as a monolayer, we visualize pigmented colonies containing RPE cells after as early as five weeks12. Once they reach sufficient size, they can be manually excised and transferred to another dish for expansion. RPE cells are notorious for dedifferentiating with each passage, and the use of anything older than five passages should be avoided (we find that sufficient numbers of cells for characterization and transplantation in animal models can easily be generated after two or three passages). Once fully differentiated, we employ multiple techniques to characterize the cells anatomically and functionally to ensure that they will serve as adequate replacements for diseased RPE. The description of these techniques, and protocol for implanting the iPS-RPE in the subretinal space of rodents, are beyond the scope of this methods paper and have been previously published12,32,41. 
While developing standardized protocols for effective derivation of iPS-RPE is clearly important for the clinics, there is also significant preclinical work to still be done in animal models. There are concerns regarding immunogenicity of iPS-derived cells, and multiple different implantation techniques, including implanting cells on artificial substrates, are being explored42,43. For these reasons, we feel that the publication of standardized protocols is beneficial to facilitate both clinical and preclinical studies. Especially if direct comparisons will be done of iPS-RPE cells derived in different labs by different research groups.

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efficient derivation of retinal pigment epithelium cells from stem cells

No cure has been discovered for age-related macular degeneration (AMD), the leading cause of vision loss in people over the age of 55. AMD is complex multifactorial disease with an unknown etiology, although it is largely thought to occur due to death or dysfunction of the retinal pigment epithelium (RPE), a monolayer of cells that underlies the retina and provides critical support for photoreceptors. RPE cell replacement strategies may hold great promise for providing therapeutic relief for a large subset of AMD patients, and RPE cells that strongly resemble primary human cells (hRPE) have been generated in multiple independent labs, including our own. In addition, the uses for iPS-RPE are not limited to cell-based therapies, but also have been used to model RPE diseases. These types of studies may not only elucidate the molecular bases of the diseases, but also serve as invaluable tools for developing and testing novel drugs. We present here an optimized protocol for directed differentiation of RPE from stem cells. Adding nicotinamide and either Activin A or IDE-1, a small molecule that mimics its effects, at specific time points, greatly enhances the yield of RPE cells. Using this technique we can derive large numbers of low passage RPE in as early as three months.

Die in diesem Manuskript dargelegt, wie in 1 dargestellt Schritten kann verwendet werden, um ohne weiteres erzeugen RPE aus Stammzellen, wie zuvor berichtet 10,12 werden. Nach Aufrechterhaltung der iPS-Linien für mehrere Wochen, beginnen pigmentierte Kolonien nach 5-7 Wochen (7 Wochen alten Kulturen werden in 2A-C gezeigt) in den Kolonien erscheinen. Diese Kolonien können weiterhin für Wochen wachsen die Kulturen gehalten. Nach Erzielung einer ausreichenden Größe, wie in...

Watch this Scientific Journal Video about Efficient Derivation of Retinal Pigment Epithelium Cells from Stem Cells at JoVE.com

Efficient Derivation of Retinal Pigment Epithelium Cells from Stem Cells

Stem cell-derived retinal pigment epithelium (RPE) cells may be used for multiple applications including cell-based therapies for retinal degeneration, disease modeling, and drug studies. Here we present a simple protocol for reproducibly deriving RPE from stem cells.

Effiziente Ableitung von Retinapigmentepithel-Zellen aus Stammzellen

No cure has been discovered for age-related macular degeneration  (AMD), the leading cause of vision loss in people over the age of 55. AMD is complex ...

efficient-derivation-retinal-pigment-epithelium-cells-from-stem

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JoVE Journal

Developmental Biology

9.1K Aufrufe.  The Scripps Research Institute. Stem cell-derived retinal pigment epithelium (RPE) cells may be used for multiple applications including cell-based therapies for retinal degeneration, disease modeling, and drug studies. Here we present a simple protocol for reproducibly deriving RPE from stem cells.