The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the Department of the Army or the Department of Defense. This research was performed while the authors Alberto Mu&#241;iz, Ramesh R Kaini, Whitney A Greene and Jae-Hyek Choi held a National Research Council Postdoctoral Research Associateship at the USAISR. This work was supported by U.S. Army Clinical Rehabilitative Medicine Research Program (CRMRP) and Military Operational Medicine Research Program (MOMRP).

1. Preparation of Culture Reagents and Culture Plates
<ol>
	<li>Prepare feeder-free stem cell culture medium by adding 100 ml of 5x serum-free supplement to 400 ml of stem cell basal medium. The medium is stable at 4 &#176;C for up to 2 weeks and at -20 &#176;C for 6 months.</li>
	<li>Add 10 &#181;M solution of rho-associated, coiled-coil containing protein kinase (Rock) inhibitor (Y-27362) to commercially available embryoid body (EB) formation medium.</li>
	<li>Prepare differentiation medium by adding 0.1 mM &#946;-me...

<ol>
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The authors have nothing to disclose.

To realize the full promise of pluripotent stem cells for cell therapy, it is necessary to regulate their differentiation in a consistent and reproducible way. This report describes protocols to form size-controlled EBs using microwell plate technology, initiate differentiation toward RPE and identify protein and gene markers of RPE. To synchronize the in vitro differentiation, homogenous sizes of EBs were formed by known numbers of iPS cells centrifuged in microwell plates by forced aggregation. Immunocytochemi...

Induced pluripotent stem (iPS) cells are a type of pluripotent stem cell derived by reprogramming adult cells with extrinsic factors1. In contrast, embryonic stem cells (ESCs), another type of pluripotent stem cell, are generated from the inner cell mass of the blastocyst2-3. Despite their different origins, iPS cells and ESCs are comparable in their unlimited capacity to replicate in vitro and in their capacity to differentiate into any cell type4-5. These characteristics of iPS cells make them ideal candidates for applications in personalized regenerative medicine. Recent research efforts are focused on developing robust differentiation protocols for producing specialized adult cells including retinal pigment epithelium (RPE)6-11.
For potential clinical applications of iPS derived cells, a directed differentiation for that specific cell type is essential. There are various methods published for directed differentiation of both ESCs and iPS cells into RPE that varies greatly in their efficiency6-7, 12-16. We still do not know many of the molecular events that govern the cell/tissue fate during development or differentiation. In recent years, efforts have been made to develop the differentiation protocol that can mimic the embryological development as much as possible. During the blastocyst phase, uncommitted population of stem cells are together in a three dimensional microenvironment. So, various strategies were applied to make the ESC/iPS cells assembled together and grow them in three dimensions. These stem cell aggregates are called embryoid bodies (EBs). Studies have shown that EB differentiation of stem cells mimic early stage of embryo development and can spontaneously give rise to primitive endoderm on its exterior surface. Later, as EB development progresses, differentiated cell phenotypes of all three germ lineages appear17-18. Therefore, EBs based differentiation protocols have attracted a lot of attention for in vitro differentiation of ESC/iPS cells and are a good candidate for RPE generation from pluripotent stem cells13.
EBs can be made using several methods from ESC/iPS cells. Initially, EBs were made by scraping off adherent colonies and maintaining them in non-adherent suspension culture. However, this approach yields heterogeneous population of EBs that causes low reproducibility. Hanging drop cell culture and microwell based EBs formation are other popular techniques for EBs formation which yield homogenous EBs of defined sizes that are highly reproducible. Furthermore, the microwell technique can yield large number of aggregates with less effort.
Differentiation of cells within EBs is regulated by a multiplex of morphogenic cues from the extracellular and intracellular microenvironment. In contrast to differentiation in a monolayer format, EBs provide a platform for complex assembly of cells and intercellular signaling to occur17. Interestingly, the number of pluripotent stem cells used to make individual EBs was observed to influence the fate of cells. For example, in a hematopoietic differentiation study of human ESCs, it was observed that 500-cell EB promoted differentiation towards myeloid lineage whereas 1,000-cell EB pushed towards erythroid lineage20. In another study, smaller EBs favored endoderm differentiation whereas larger EBs promoted towards neuro-ectoderm differentiation11, 17.
These past studies strongly suggest that the number of ESC/iPS cells used to make individual EBs affect the EBs based differentiation to any cell types. However, to our knowledge, there are no current studies that have elucidated the impact of EBs size in its propensity to differentiate towards RPE. The goal of this study is to characterize the influence of EB size on induced pluripotent stem (iPS) cells - retinal pigment epithelium (iPS-RPE) differentiation and to identify the optimum cell number to make the EBs for directed differentiation towards RPE lineage.

<table border="0" cellpadding="0" cellspacing="0" width="722">
	<tbody>
		<tr height="36">
			<td height="36" style="height:36px;width:239px;">Name of Material/ Equipment</td>
			<td style="width:183px;">Company</td>
			<td style="width:140px;">Catalog Number</td>
			<td style="width:161px;">Comments/Description</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">mTeSR1 media + 5X supplement</td>
			<td>Stem Cell Technologies</td>
			<td>5850</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Y-27632 (Rock Inhibitor)</td>
			<td>Stem Cell Technologies</td>
			<td>72304</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">DMEM/F12</td>
			<td>Life Technologies</td>
			<td>11330-032</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">2-Mercaptoethanol</td>
			<td style="width:183px;">Sigma</td>
			<td style="width:140px;">M-7154</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">Non essential amino acids</td>
			<td style="width:183px;">Hyclone(Fisher)</td>
			<td>SH30853.01</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">Knockout serum replacement</td>
			<td style="width:183px;">Life Technologies</td>
			<td style="width:140px;">10828-028</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">Gentamicin&#160;</td>
			<td style="width:183px;">Life Technologies</td>
			<td style="width:140px;">15750-060</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">L-Glutamine</td>
			<td style="width:183px;">Life Technologies</td>
			<td style="width:140px;">25030-081</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">MEM media</td>
			<td style="width:183px;">Life Technologies</td>
			<td style="width:140px;">10370-021</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">N1 supplement</td>
			<td style="width:183px;">Sigma</td>
			<td style="width:140px;">N-6530-5ML</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">Taurine</td>
			<td style="width:183px;">Sigma</td>
			<td style="width:140px;">T-8691-25G</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">Hydrocortisone</td>
			<td style="width:183px;">Sigma</td>
			<td style="width:140px;">H0888-1G</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">Fetal bovine serum</td>
			<td style="width:183px;">Hyclone(Fisher)</td>
			<td>SH3008803HI</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Triiodo-l-thyronine sodium&#160; salt</td>
			<td style="width:183px;">Sigma</td>
			<td style="width:140px;">T6397</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">Sodium hydroxide</td>
			<td style="width:183px;">Sigma</td>
			<td style="width:140px;">S5881</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">Dispase</td>
			<td style="width:183px;">Life Technologies</td>
			<td>17105-041</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">Matrigel</td>
			<td style="width:183px;">BD Biosciences</td>
			<td style="width:140px;">354277</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">Phosphate buffered saline</td>
			<td style="width:183px;">Hyclone(Fisher)</td>
			<td>10010-023</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">Aggrewell 400 plate</td>
			<td style="width:183px;">Stem Cell Technologies</td>
			<td>27940</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">AggreWell medium</td>
			<td>Stem Cell Technologies</td>
			<td>5893</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">Accutase</td>
			<td>Stem Cell Technologies</td>
			<td>7920</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:239px;">BD Cytofix/Cytoperm Fixation/Permeabilization Kit</td>
			<td>BD Biosciences</td>
			<td>554714</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">Mouse Anti-PAX6 antibody</td>
			<td colspan="2">Developmental Studies Hybridoma Bank</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">Rabbit Anti- RX antibody</td>
			<td>Abcam</td>
			<td>Ab23340</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">Mouse&#160; Anti-MITF antibody</td>
			<td>Thermo Scientific</td>
			<td>MS-772-P</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">Rabbit Anti-ZO-1 antibody</td>
			<td>Invitrogen</td>
			<td>40-2200</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">RNeasy plus mini kit</td>
			<td>Qiagen</td>
			<td>74134</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">PCR master mix</td>
			<td>promega</td>
			<td>M7502</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">High capacity RNA to c DNA kit</td>
			<td style="width:183px;">Life Technologies</td>
			<td>4387406</td>
			<td></td>
		</tr>
	</tbody>
</table>

deriving retinal pigment epithelium (rpe) from induced pluripotent stem (ips) cells by different sizes of embryoid bodies

Pluripotent stem cells possess the ability to proliferate indefinitely and to differentiate into almost any cell type. Additionally, the development of techniques to reprogram somatic cells into induced pluripotent stem (iPS) cells has generated interest and excitement towards the possibility of customized personal regenerative medicine. However, the efficiency of stem cell differentiation towards a desired lineage remains low. The purpose of this study is to describe a protocol to derive retinal pigment epithelium (RPE) from iPS cells (iPS-RPE) by applying a tissue engineering approach to generate homogenous populations of embryoid bodies (EBs), a common intermediate during in vitro differentiation. The protocol applies the formation of specific size of EBs using microwell plate technology. The methods for identifying protein and gene markers of RPE by immunocytochemistry and reverse-transcription polymerase chain reaction (RT-PCR) are also explained. Finally, the efficiency of differentiation in different sizes of EBs monitored by fluorescence-activated cell sorting (FACS) analysis of RPE markers is described. These techniques will facilitate the differentiation of iPS cells into RPE for future applications.

In this experiment, iPS cells were cultured and differentiated into the RPE lineage from EBs. EBs of controlled sizes were formed using microwell plates. As seen in Figure 1 EB formation was homogenous in the microwell plates. These EBs were then collected and plated on 6-well plates (Figure 2).
RPE can be identified by their classical hexagonal morphology, pigmentation, and expression of RPE markers. After 12 weeks of culture, the 200-cell EBs had developed a...

Watch this Scientific Journal Video about Deriving Retinal Pigment Epithelium RPE from Induced Pluripotent Stem iPS Cells by Different Sizes of Embryoid Bodies at JoVE.com

Deriving Retinal Pigment Epithelium RPE from Induced Pluripotent Stem iPS Cells by Different Sizes of Embryoid Bodies

The objective of this report is to describe the protocols to derive the retinal pigment epithelium (RPE) from induced pluripotent stem (iPS) cells using different sizes of embryoid bodies.

Deriving Retinal Pigment Epithelium (RPE) from Induced Pluripotent Stem (iPS) Cells by Different Sizes of Embryoid Bodies

Pluripotent stem cells possess the ability to proliferate indefinitely and to differentiate into almost any cell type. Additionally, the development of ...

deriving-retinal-pigment-epithelium-rpe-from-induced-pluripotent-stem

Research

JoVE Journal

Developmental Biology

10.5K vistas.  U.S. Army Institute of Surgical Research.  El objetivo de este informe es describir los protocolos para derivar el epitelio pigmentario de la retina (EPR) a partir de células madre pluripotentes inducidas (iPS) utilizando diferentes tamaños de cuerpos embrionarios. 