This study is supported by the Japan Society for the Promotion of Science Overseas Research Fellowships (S.G.), a Loris and David Rich Postdoctoral Scholar (S.G.), and a grant from the National Eye Institute of the National Institutes of Health (R01EY012392; C.F.W.).

All animal care and treatments used in this study conformed to the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research. The experimental protocols were approved by the Animal Care and Use Committee of the University of California, Berkeley.
1. Enucleation of the guinea pig eye
<ol>
	<li>Euthanize a guinea pig&#160;with an intracardiac injection of sodium pentobarbital delivered under anesthesia (5% isoflurane in oxygen).</li>
	<li>Enucleate the eyes with the aid of forceps and scissors, and immediately transfer them to a 10 cm Petri dish with sterile phosphate-buffered saline (PBS) for washing. Transfer the eyes to fresh PBS solution. 
	&#8203;NOTE: A 6-well plate containing 4 mL of solution per well is recommended.</li>
</ol>
2. Isolation of the ocular posterior eye cup and RPE/choroid/sclera complex
<ol>
	<li>With the aid of a dissecting microscope, use an 18 G needle to make an initial small incision in the sclera, approximately 1.0 mm behind the limbal boundary (i.e., between the cornea and sclera) (Figure 1A); then use scissors to remove the anterior segment, including the cornea, iris, ciliary body, and crystalline lens.</li>
	<li>Next, working with the remaining posterior ocular segment eye cup, detach the retina from the RPE/choroid/sclera complex; use forceps to first grasp and then gently tug on the zonule of Zinn and then to progressively peel away the retina without fragmentation (Figure 1B). 
	&#8203;NOTE: The retina must not be directly grasped to avoid retinal fragmentation and incomplete retinal tissue isolation. The use of a microscope is essential for this dissection step.</li>
</ol>
3. Isolation of the RPE from the choroid
<ol>
	<li>After the retina has been completely removed, immerse the remaining posterior eye cup, which includes the RPE, choroid, and sclera, in tissue storage reagent for 5 min (see the Table of Materials). 
	NOTE: Use a 12-well plate with identified wells, each filled with 2 mL of the tissue storage reagent.</li>
	<li>Transfer the eye cup to another well filled with 4 mL of PBS for 10 s before moving it to a third well filled with 2 mL of PBS.</li>
	<li>Attach a 30 G needle to a 1 mL syringe filled with PBS for the final RPE isolation step. Gently push on the syringe to create a jet stream of PBS; first, aim this stream at the RPE to make a small tear or hole in it, and then direct the stream of PBS into the created opening to detach the RPE as a sheet from the choroid (Figure 1C). 
	NOTE: The detachment of the RPE as a sheet yields the largest RPE sample. Again, the use of a microscope is essential for this step.</li>
	<li>After detaching the RPE from the choroid (Figure 1D), collect the RPE tissue in a needleless 1 mL syringe, and then transfer the collected sample to a 1.5 mL tube.</li>
	<li>Centrifuge the 1.5 mL tube with the collected RPE at 8,000 &#215; g for 1 min to obtain an RPE pellet (Figure 2A).</li>
	<li>Discard the PBS solution, and replace it with 350 mL of lysis buffer, as included in RNA isolation kits (see the Table of Materials); pipette 20x to mix and, thus, preserve the quality of the sample. For longer-term storage and preservation, transfer the samples to a &#8722;80 &#176;C freezer. 
	&#8203;NOTE: The lysis buffer is a proprietary component of the RNA isolation kit for cell and tissue lysis before RNA isolation and simultaneous RNA/DNA/protein isolation. To inactivate the RNAses in the lysate, be sure to add &#946;-mercaptoethanol to the lysis buffer (10 &#181;L of &#946;-mercaptoethanol per 1 mL of lysis buffer).</li>
</ol>
4. RPE-RNA extraction
<ol>
	<li>Use an RNA isolation kit (see the Table of Materials) to isolate and collect the RNA from the RPE samples following the manufacturer&#39;s instructions provided. Evaluate the quality of the sample via electrophoresis. 
	NOTE: The described protocol yielded a good-quality product (i.e., RNA integrity number [RIN] over 8.0).</li>
</ol>

<ol>
	<li>Strauss, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+retinal+pigment+epithelium+in+visual+function.">The retinal pigment epithelium in visual function.</a> Physiological Reviews. 85 (3), 845-881 (2005).</li><li>Amram, B., Cohen-Tayar, Y., David, A., Ashery-Padan, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+retinal+pigmented+epithelium+-+from+basic+developmental+biology+research+to+translational+approaches.">The retinal pigmented epithelium - from basic developmental biology research to translational approaches.</a> The International Journal of Developmental Biology. 61 (3-4-5), 225-234 (2017).</li><li>Goto, S., 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=Neural+retina-specific+Aldh1a1+controls+dorsal+choroidal+vascular+development+via+Sox9+expression+in+retinal+pigment+epithelial+cells.">Neural retina-specific Aldh1a1 controls dorsal choroidal vascular development via Sox9 expression in retinal pigment epithelial cells.</a> Elife. 7, 32358 (2018).</li><li>Rymer, J., Wildsoet, C. F. <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+the+retinal+pigment+epithelium+in+eye+growth+regulation+and+myopia:+A+review.">The role of the retinal pigment epithelium in eye growth regulation and myopia: A review.</a> Visual Neuroscience. 22 (3), 251-261 (2005).</li><li>Wallman, J., 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=Moving+the+retina:+Choroidal+modulation+of+refractive+state.">Moving the retina: Choroidal modulation of refractive state.</a> Vision Research. 35 (1), 37-50 (1995).</li><li>Wu, H., 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=Scleral+hypoxia+is+a+target+for+myopia+control.">Scleral hypoxia is a target for myopia control.</a> Proceedings of the National Academy of Sciences of the United States of America. 115 (30), 7091-7100 (2018).</li><li>Troilo, D., 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=Imi+-+Report+on+experimental+models+of+emmetropization+and+myopia.">Imi - Report on experimental models of emmetropization and myopia.</a> Investigative Ophthalmology and Visual Science. 60 (3), 31-88 (2019).</li><li>Jiang, X., 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=Violet+light+suppresses+lens-induced+myopia+via+neuropsin+(OPN5)+in+mice.">Violet light suppresses lens-induced myopia via neuropsin (OPN5) in mice.</a> Proceedings of the National Academy of Sciences of the United States of America. 118 (22), e2018840118 (2021).</li><li>Zhang, Y., Wildsoet, C. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RPE+and+choroid+mechanisms+underlying+ocular+growth+and+myopia.">RPE and choroid mechanisms underlying ocular growth and myopia.</a> Progress in Molecular Biology and Translational Science. 134, 221-240 (2015).</li><li>Jager, R. D., Mieler, W. F., Miller, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Age-related+macular+degeneration.">Age-related macular degeneration.</a> New England Journal of Medicine. 358 (24), 2606-2617 (2008).</li><li>McLeod, D. S., 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=Relationship+between+RPE+and+choriocapillaris+in+age-related+macular+degeneration.">Relationship between RPE and choriocapillaris in age-related macular degeneration.</a> Investigative Opthalmology and Visual Science. 50 (10), 4982 (2009).</li><li>Bhutto, I., Lutty, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Understanding+age-related+macular+degeneration+(AMD):+Relationships+between+the+photoreceptor/retinal+pigment+epithelium/Bruch's+membrane/choriocapillaris+complex.">Understanding age-related macular degeneration (AMD): Relationships between the photoreceptor/retinal pigment epithelium/Bruch's membrane/choriocapillaris complex.</a> Molecular Aspects of Medicine. 33 (4), 295-317 (2012).</li><li>Shelton, L., 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=Microarray+analysis+of+choroid/RPE+gene+expression+in+marmoset+eyes+undergoing+changes+in+ocular+growth+and+refraction.">Microarray analysis of choroid/RPE gene expression in marmoset eyes undergoing changes in ocular growth and refraction.</a> Molecular Vision. 14, 1465-1479 (2008).</li><li>Wang, S., Liu, S., Mao, J., Wen, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+retinoic+acid+on+the+tight+junctions+of+the+retinal+pigment+epithelium-choroid+complex+of+guinea+pigs+with+lens-induced+myopia+in+vivo.">Effect of retinoic acid on the tight junctions of the retinal pigment epithelium-choroid complex of guinea pigs with lens-induced myopia in vivo.</a> International Journal of Molecular Medicine. 33 (4), 825-832 (2014).</li><li>He, L., Frost, M. R., Siegwart, J. T., Norton, T. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Altered+gene+expression+in+tree+shrew+retina+and+retinal+pigment+epithelium+produced+by+short+periods+of+minus-lens+wear.">Altered gene expression in tree shrew retina and retinal pigment epithelium produced by short periods of minus-lens wear.</a> Experimental Eye Research. 168 (3), 77-88 (2018).</li><li>Nickla, D. L., Wallman, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+multifunctional+choroid.">The multifunctional choroid.</a> Progress in Retinal and Eye Research. 29 (2), 144-168 (2010).</li><li>Zhang, Y., Liu, Y., Wildsoet, C. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bidirectional,+optical+sign-dependent+regulation+of+BMP2+gene+expression+in+chick+retinal+pigment+epithelium.">Bidirectional, optical sign-dependent regulation of BMP2 gene expression in chick retinal pigment epithelium.</a> Investigative Ophthalmology and Visual Science. 53 (10), 6072-6080 (2012).</li><li>Xin-Zhao Wang, C., Zhang, K., Aredo, B., Lu, H., Ufret-Vincenty, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+method+for+the+rapid+isolation+of+RPE+cells+specifically+for+RNA+extraction+and+analysis.">Novel method for the rapid isolation of RPE cells specifically for RNA extraction and analysis.</a> Experimental Eye Research. 102 (1), 1-9 (2012).</li><li>Goto, S., 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=Gene+expression+signatures+of+contact+lens-induced+myopia+in+guinea+pig+retinal+pigment+epithelium.">Gene expression signatures of contact lens-induced myopia in guinea pig retinal pigment epithelium.</a> Investigative Opthalmology and Visual Science. 63 (9), 25 (2022).</li><li>De Schaepdrijver, L., Simoens, P., Lauwers, H., De Geest, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Retinal+vascular+patterns+in+domestic+animals.">Retinal vascular patterns in domestic animals.</a> Research in Veterinary Science. 47 (1), 34-42 (1989).</li><li>Araki, H., 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=Base-resolution+methylome+of+retinal+pigment+epithelial+cells+used+in+the+first+trial+of+human+induced+pluripotent+stem+cell-based+autologous+transplantation.">Base-resolution methylome of retinal pigment epithelial cells used in the first trial of human induced pluripotent stem cell-based autologous transplantation.</a> Stem Cell Reports. 13 (4), 761-774 (2019).</li><li>Sonoda, S., 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=A+protocol+for+the+culture+and+differentiation+of+highly+polarized+human+retinal+pigment+epithelial+cells.">A protocol for the culture and differentiation of highly polarized human retinal pigment epithelial cells.</a> Nature Protocols. 4 (5), 662-673 (2009).</li><li>Fernandez-Godino, R., Garland, D. 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The authors declare no competing financial interests.

In this article, we describe a method for isolating RPE, appropriate for RPE gene expression analyses, from the eyes of young, pigmented guinea pigs. The merits of this protocol are that it yields high-quality RPE samples that are relatively free from contamination, with&#160;RNA suitably preserved for RNA-specific analyses and, yet, is relatively simple and efficient. While in the example provided here, the RPE samples were collected from the eyes of a young (2 weeks old)&#160;guinea pig, the protocol has also been used...

The RPE comprises a unique monolayer of pigmented cells located between the neural retina and the vascular choroid, and the RPE has well-recognized roles in the development and maintenance of normal retinal function, including phototransduction1,2. More recently, the RPE has been assigned an additional key role in eye growth regulation3 and, thus, the development of myopia4. This assignment is based on the RPE&#39;s critical location,&#160;interposed between the retina and choroid and the now broad acceptance that eye growth and, thus, refractive errors are regulated locally5. The RPE is believed to play a key role as a signal relay, linking the retina, the assumed source of growth modulatory signals, to the choroid and sclera, the two targets of the relayed signals6,7,8.
The increase in axial length that characterizes most myopia cannot be considered benign, with pathophysiological changes involving the retina, choroid, and/or sclera representing unavoidable and now well-recognized consequences of excessive ocular elongation7,9. In this context, the RPE is perhaps the most vulnerable, since, being a nonmitotic tissue, it is only able to accommodate the expanding vitreous chamber by the stretching and thinning of individual cells. While its role in myopia-related pathologies, such as myopic macular degeneration, is yet to be fully understood, the RPE has been implicated in the pathogenesis of a number of other retinal diseases, including geographic atrophy, one of the leading causes of blindness, which is associated with documented abnormalities in the retina, RPE, and choroid10,11,12.
The successful isolation of RPE cells, free from contamination from adjacent ocular tissues, potentially opens up many research opportunities to gain new insights into the mechanisms underlying a variety of eye/retinal diseases. However, the isolation of the RPE has proven challenging, with many published studies making use of combined retina/RPE or RPE/choroid samples for this reason13,14,15. Studies involving the successful isolation of the RPE of a quality suitable for molecular biology studies has been limited to chick and mouse eyes16,17. For example, the simultaneous RPE isolation and RNA stabilization (SRIRS) method described by Wang et al.18. To isolate RPE cells in mice does not appear to work well in guinea pig eyes. The protocol described here represents a refinement of an approach that was initially prototyped with tree shrew eyes by one of the authors (M.F.) and has proven to yield high-quality RPE samples, appropriate for RNA and other molecular biology analyses, from the eyes of young pigmented guinea pigs19.

<table><tbody><tr><td>1 mL Syringe with Slip Tip</td><td>Bd Vacutainer Labware Medical</td><td>22-253-260</td><td></td></tr><tr><td>2-Mercaptoethanol</td><td>Invitrogen</td><td>21985-023</td><td></td></tr><tr><td>6 Well Tissue Culture Plate with Lid, Flat Bottom, Sterile</td><td>pectrum Chemical Mfg. Corp</td><td>970-95008</td><td></td></tr><tr><td>12 Well Tissue Culture Plate with Lid, Individual, Sterile</td><td>Thomas Scientific LLC</td><td>1198D72</td><td></td></tr><tr><td>Agilent 2100 Bioanalyzer</td><td></td><td></td><td>automated electrophoresis to check RNA quality</td></tr><tr><td>Balanced Salt Solutions</td><td>Gibco</td><td>10010031</td><td></td></tr><tr><td>Bonn Micro Forceps, Straight Smooth, 0.3 mm Tip, 7 cm</td><td>Fine Science Tools, Inc.</td><td>11083-07</td><td></td></tr><tr><td>Dumont forceps no. 5</td><td>ROBOZ</td><td>RS-5045</td><td></td></tr><tr><td>Hypodermic disposable needles</td><td>Exelint International, Co.</td><td>26419</td><td></td></tr><tr><td>Hypodermic disposable needles</td><td>Exelint International, Co.</td><td>26437</td><td></td></tr><tr><td>MiniSpin Microcentrifuges</td><td>Eppendorf</td><td>540108</td><td>Max. Speed: 8,000 g</td></tr><tr><td>RNAlater Stabilization Solution</td><td>Invitrogen</td><td>AM7020</td><td>tissue storage reagent</td></tr><tr><td>RNeasy Mini kits</td><td>Qiagen</td><td>74104</td><td>RNA isolation kit</td></tr><tr><td>Student Vannas Spring Scissors</td><td>Fine Science Tools, Inc.</td><td>91500-09</td><td></td></tr></tbody></table>

isolation of retinal pigment epithelial cells from guinea pig eyes

This protocol describes the isolation of cells of the retinal pigment epithelium (RPE) from the eyes of young pigmented guinea pigs for potential application in molecular biology studies, including gene expression analyses. In the context of eye growth regulation and myopia, the RPE likely plays a role as a cellular relay for growth modulatory signals, as it is located between the retina and the two walls of the eye, such as the choroid and sclera. While protocols for isolating the RPE have been developed for both chicks and mice, these protocols have proven not to be directly translatable to the guinea pig, which has become an important and widely used mammalian myopia model. In this study, molecular biology tools were used to examine the expression of specific genes to confirm that the samples were free of contamination from the adjacent tissues. The value of this protocol has already been demonstrated in an RNA-Seq study of RPE from young pigmented guinea pigs exposed to myopia-inducing optical defocus. Beyond eye growth regulation, this protocol has other potential applications in studies of retinal diseases, including myopic maculopathy, one of the leading causes of blindness in myopes, in which the RPE has been implicated. The main advantage of this technique is that it is relatively simple and&#160;once perfected, yields high-quality RPE samples suitable for molecular biology studies, including RNA analysis.

The analysis of the RPE samples collected using the above protocol showed well-preserved RNA (RIN &#62;8.0, Figure 2B), with 240.2 ng &#177; 35.1 ng per eye (n = 8, NanoDrop, Figure 2B). To further evaluate the quality of the isolated RPE samples, particularly the absence of choroidal and scleral contaminants, we examined the expression of representative genes for each of the latter tissues in the RPE samples19. The RPE samples demonstrat...

Watch this Scientific Journal Video about Isolation of Retinal Pigment Epithelial Cells from Guinea Pig Eyes at JoVE.com

Isolation of Retinal Pigment Epithelial Cells from Guinea Pig Eyes

We describe a simple and efficient method for isolating cells of the retinal pigment epithelium (RPE) cells from the eyes of young pigmented guinea pigs. This procedure allows for follow-up molecular biology studies on the isolated RPE, including gene expression analyses.

This protocol describes the isolation of cells of the retinal pigment epithelium (RPE) from the eyes of young pigmented guinea pigs for potential ...

isolation-of-retinal-pigment-epithelial-cells-from-guinea-pig-eyes

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JoVE Journal

Biology

2.1K Views.  University of California, Berkeley. Retinaal pigmentepitheel of RPE is van cruciaal belang voor de gezondheid van het netvlies. En het bestuderen van de geïsoleerde RPE is cruciaal voor de netvliesaandoening. Deze methode van RPE-isolatie van de cavia, een populair bijziendheidsmodel, helpt bij het oplossen van het uitdagende probleem.Het grote voordeel van deze techniek is dat het relatief eenvoudig is en een hoogwaardig RPE-monster oplevert dat geschikt is voor de biologische moleculaire studies inclusief de RPE-analy...

Video: Isolation of Retinal Pigment Epithelial Cells from Guinea Pig Eyes

Isolation of Retinal Stem Cells from the Mouse Eye

The adult mouse retinal stem cell (RSC) is a rare quiescent cell found within the ciliary epithelium (CE) of the mammalian eye1,2,3. The CE is made up of non-pigmented inner and pigmented outer cell layers, and the clonal RSC colonies that arise from a single pigmented cell from the CE are made up of both pigmented and non-pigmented cells which can be differentiated to form all the cell types of the neural retina and the RPE. There is some controversy about whether all the cells within the spheres all contain at least some pigment4; however the cells are still capable of forming the different cell types found within the neural retina1-3. In some species, such as amphibians and fish, their eyes are capable of regeneration after injury5, however; the mammalian eye shows no such regenerative properties. We seek to identify the stem cell in vivo and to understand the mechanisms that keep the mammalian retinal stem cells quiescent6-8, even after injury as well as using them as a potential source of cells to help repair physical or genetic models of eye injury through transplantation9-12. Here we describe how to isolate the ciliary epithelial cells from the mouse eye and grow them in culture in order to form the clonal retinal stem cell spheres. Since there are no known markers of the stem cell in vivo, these spheres are the only known way to prospectively identify the stem cell population within the ciliary epithelium of the eye.

In this video, we will demonstrate how to isolate retinal stem cells from the ciliary epithelium of the mouse eye and grow them in culture to form clonal retinal spheres. The spheres that are isolated possess the cardinal properties of stem cells: self-renewal and multipotentiality.

The adult mouse retinal stem cell (RSC) is a rare quiescent cell found within the ciliary epithelium (CE) of the mammalian eye1,2,3. The CE is made up of ...

Isolation and Culture of Adult Epithelial Stem Cells from Human Skin

The homeostasis of all self-renewing tissues is dependent on adult stem cells. As undifferentiated stem cells undergo asymmetric divisions, they generate daughter cells that retain the stem cell phenotype and transit-amplifying cells (TA cells) that migrate from the stem cell niche, undergo rapid proliferation and terminally differentiate to repopulate the tissue.
Epithelial stem cells have been identified in the epidermis, hair follicle, and intestine as cells with a high in vitro proliferative potential and as slow-cycling label-retaining cells in vivo 1-3. Adult, tissue-specific stem cells are responsible for the regeneration of the tissues in which they reside during normal physiologic turnover as well as during times of stress 4-5. Moreover, stem cells are generally considered to be multi-potent, possessing the capacity to give rise to multiple cell types within the tissue 6. For example, rodent hair follicle stem cells can generate epidermis, sebaceous glands, and hair follicles 7-9. We have shown that stem cells from the human hair follicle bulge region exhibit multi-potentiality 10.
Stem cells have become a valuable tool in biomedical research, due to their utility as an in vitro system for studying developmental biology, differentiation, tumorigenesis and for their possible therapeutic utility. It is likely that adult epithelial stem cells will be useful in the treatment of diseases such as ectodermal dysplasias, monilethrix, Netherton syndrome, Menkes disease, hereditary epidermolysis bullosa and alopecias 11-13. Additionally, other skin problems such as burn wounds, chronic wounds and ulcers will benefit from stem cell related therapies 14,15. Given the potential for reprogramming of adult cells into a pluripotent state (iPS cells)16,17, the readily accessible and expandable adult stem cells in human skin may provide a valuable source of cells for induction and downstream therapy for a wide range of disease including diabetes and Parkinson's disease.

A rapid, robust way of isolating viable adult epithelial stem cells from human skin is described. The method utilizes enzymatic digestion of skin collagen matrix , followed by plucking of hair follicles and isolation of single cell suspensions or tissue fragments for cell culture.

The homeostasis of all self-renewing tissues is dependent on adult stem cells. As undifferentiated stem cells undergo asymmetric divisions, they generate ...

MicroRNA Expression Profiles of Human iPS Cells, Retinal Pigment Epithelium Derived From iPS, and Fetal Retinal Pigment Epithelium

The objective of this report is to describe the protocols for comparing the microRNA (miRNA) profiles of human induced-pluripotent stem (iPS) cells, retinal pigment epithelium (RPE) derived from human iPS cells (iPS-RPE), and fetal RPE. The protocols include collection of RNA for analysis by microarray, and the analysis of microarray data to identify miRNAs that are differentially expressed among three cell types. The methods for culture of iPS cells and fetal RPE are explained. The protocol used for differentiation of RPE from human iPS is also described. The RNA extraction technique we describe was selected to allow maximal recovery of very small RNA for use in a miRNA microarray. Finally, cellular pathway and network analysis of microarray data is explained. These techniques will facilitate the comparison of the miRNA profiles of three different cell types.

The microRNA (miRNA) profiles of human induced-pluripotent stem (iPS) cells, retinal pigment epithelium (RPE) derived from human induced-pluripotent stem (iPS) cells (iPS-RPE), and fetal RPE, were compared.

The objective of this report is to describe the protocols for comparing the microRNA (miRNA) profiles of human induced-pluripotent stem (iPS) cells, ...

Characterization and Morphological Dynamics of Cultured Primary Murine RPE

A Simplified Method for Isolation and Culture of Retinal Pigment Epithelial Cells from Adult Mice

Retinal pigment epithelial cells (RPE) are critical for the proper function of the retina. RPE dysfunction is involved in the pathogenesis of important retinal diseases, such as age-related macular degeneration, retinitis pigmentosa, and diabetic retinopathy. We present a streamlined approach for the isolation of RPE from murine adult eyes. In contrast to previously reported methods, this approach enables the isolation and culture of highly pure RPE from adult mice. This simple and fast method does not require extensive technical skill and is achievable with basic scientific tools and reagents. Primary RPE are isolated from C57BL/6 background mice aged 3- to 14-weeks by enucleation of the eye followed by the removal of the anterior segment. Enzymatic trypsinization and centrifugation are used to dissociate and isolate the RPE from the eyecup. In conclusion, this approach offers a quick and effective protocol for the utilization of RPE in the study of retinal function and disease.

Author Spotlight: Efficient Isolation of Primary Retinal Pigment Epithelial Cells from Adult Mice for Retinopathy Research

Retinal pigment epithelium (RPE) acts as a crucial barrier between the choroid and retina, promoting the health and function of retinal cell types, such as photoreceptors. Herein, we describe a simple and effective protocol for isolating and culturing adult murine RPE.

Retinal pigment epithelial cells (RPE) are critical for the proper function of the retina. RPE dysfunction is involved in the pathogenesis of important ...

Neuroscience

Isolation, Culture, and Genetic Engineering of Mammalian Primary Pigment Epithelial Cells for Non-Viral Gene Therapy

Age-related macular degeneration (AMD) is the most frequent cause of blindness in patients &#62;60 years, affecting ~30 million people worldwide. AMD is a multifactorial disease influenced by environmental and genetic factors, which lead to functional impairment of the retina due to retinal pigment epithelial (RPE) cell degeneration followed by photoreceptor degradation. An ideal treatment would include the transplantation of healthy RPE cells secreting neuroprotective factors to prevent RPE cell death and photoreceptor degeneration. Due to the functional and genetic similarities and the possibility of a less invasive biopsy, the transplantation of iris pigment epithelial (IPE) cells was proposed as a substitute for the degenerated RPE. Secretion of neuroprotective factors by a low number of subretinally-transplanted cells can be achieved by Sleeping Beauty (SB100X) transposon-mediated transfection with genes coding for the pigment epithelium-derived factor (PEDF) and/or the granulocyte macrophage-colony stimulating factor (GM-CSF). We established the isolation, culture, and SB100X-mediated transfection of RPE and IPE cells from various species including rodents, pigs, and cattle. Globes are explanted and the cornea and lens are removed to access the iris and the retina. Using a custom-made spatula, IPE cells are removed from the isolated iris. To harvest RPE cells, a trypsin incubation may be required, depending on the species. Then, using RPE-customized spatula, cells are suspended in medium. After seeding, cells are monitored twice per week and, after reaching confluence, transfected by electroporation. Gene integration, expression, protein secretion, and function were confirmed by qPCR, WB, ELISA, immunofluorescence, and functional assays. Depending on the species, 30,000-5 million (RPE) and 10,000-1.5 million (IPE) cells can be isolated per eye. Genetically modified cells show significant PEDF/GM-CSF overexpression with the capacity to reduce oxidative stress and offers a flexible system for ex vivo&#160;analyses and in vivo studies transferable to humans to develop ocular gene therapy approaches.

Here, a protocol to isolate and transfect primary iris and retinal pigment epithelial cells from various mammals (mice, rat, rabbit, pig, and bovine) is presented. The method is ideally suited to study ocular gene therapy approaches in various set-ups for ex vivo&#160;analyses and&#160;in vivo studies transferable to humans.

Age-related macular degeneration (AMD) is the most frequent cause of blindness in patients &#62;60 years, affecting ~30 million people worldwide. AMD is a ...

Isolation of Primary Mouse Retinal Pigmented Epithelium Cells

The retinal pigmented epithelium (RPE) layer lies immediately behind the photoreceptors and harbors a complex metabolic system that plays several critical roles in maintaining the photoreceptors' function. Thus, the RPE structure and function are essential to sustain normal vision. This manuscript presents an established protocol for primary mouse RPE cell isolation. RPE isolation is a great tool to investigate the molecular mechanisms underlying RPE pathology in the different mouse models of ocular disorders. Furthermore, RPE isolation can help in comparing primary mouse RPE cells isolated from wild-type and genetically modified mice, as well as testing drugs that can accelerate the development of therapy for visual disorders. The manuscript presents a step-by-step RPE isolation protocol; the entire procedure, from enucleation to seeding, takes approximately 4 hours. The media shouldn't be changed for 5-7 days after seeding, to allow the growth of the isolated cells without disturbance. This process is followed by the characterization of morphology, pigmentation, and specific markers in the cells via immunofluorescence. Cells can be passaged a maximum of three or four times.

This manuscript describes a simplified protocol for the isolation of retinal pigmented epithelium (RPE) cells from mouse eyes in a stepwise manner. The protocol includes the enucleation and dissection of mouse eyes, followed by the isolation, seeding, and culturing of RPE cells.

The retinal pigmented epithelium (RPE) layer lies immediately behind the photoreceptors and harbors a complex metabolic system that plays several critical ...

A Cost-Effective Method for Isolating Primary RPE Cells from Porcine Eyes

Isolation of Primary Porcine Retinal Pigment Epithelial Cells for In Vitro Modeling

The retinal pigment epithelium (RPE) is a crucial monolayer in the outer retina responsible for supporting photoreceptors. RPE degeneration commonly occurs in diseases marked by progressive vision loss, such as age-related macular degeneration (AMD). Research on AMD often relies on human donor eyes or induced pluripotent stem cells (iPSCs) to represent the RPE. However, these RPE sources require extended differentiation periods and substantial expertise for culturing. Additionally, some research institutions, particularly those in rural areas, lack easy access to donor eyes. While a commercially available immortalized RPE cell line (ARPE-19) exists, it lacks essential in vivo RPE features and is not widely accepted in many ophthalmology research publications. There is a pressing need to obtain representative primary RPE cells from a more readily available and cost-effective source. This protocol elucidates the isolation and subculture of primary RPE cells obtained post-mortem from porcine eyes, which can be sourced locally from commercial or academic suppliers. This protocol necessitates common materials typically found in tissue culture labs. The result is a primary, differentiated, and cost-effective alternative to iPSCs, human donor eyes, and ARPE-19 cells.

Author Spotlight: Modeling Retinal Pathologies with Enhanced RPE Cell-Based Disease Models

This protocol outlines the procedure for obtaining and culturing primary retinal pigment epithelial (RPE) cells from locally sourced porcine eyes. These cells serve as a high-quality alternative to stem cells and are suitable for in vitro retinal research.

The retinal pigment epithelium (RPE) is a crucial monolayer in the outer retina responsible for supporting photoreceptors. RPE degeneration commonly ...

Isolating RPE and IPE Cells from Bovine Eye: A Procedure to  Harvest and Culture Bovine Primary Pigment Epithelial Cells

Source: Bascuas, T. et al., <a href="https://www.jove.com/v/62145">Isolation, Culture, and Genetic Engineering of Mammalian Primary Pigment Epithelial Cells for Non-Viral Gene Therapy.</a> J. Vis. Exp. (2021).
This video demonstrates the procedure to isolate the retinal pigment epithelial, or RPE, cells and iris pigment epithelial, or IPE, cells from harvested bovine eyes. The isolated cells can be cultured to study their role in the treatment of ocular diseases.

Source: Bascuas, T. et al., Isolation, Culture, and Genetic Engineering of Mammalian Primary Pigment Epithelial Cells for Non-Viral Gene Therapy. J. Vis. ...

JoVE Encyclopedia of Experiments

Large Animal Models

Bovine

Isolating IPE and RPE Cells: A Technique for Obtaining Ocular Pigment Epithelial Cells from Rabbit Eye

Source: Bascuas, T., et al. <a href="https://www.jove.com/v/62145">Isolation, Culture, and Genetic Engineering of Mammalian Primary Pigment Epithelial Cells for Non-Viral Gene Therapy.</a> J. Vis. Exp. (2021).
In this video, we show a procedure to obtain ocular pigment epithelial cells from a rabbit model. The cells are helpful in developing therapeutic strategies for retinal degenerative diseases.

Source: Bascuas, T., et al. Isolation, Culture, and Genetic Engineering of Mammalian Primary Pigment Epithelial Cells for Non-Viral Gene Therapy. J. Vis. ...

Leporine

Isolation of IPE and RPE cells: A Technique to Obtain Pigmented Epithelial Cells from Isolated Porcine Eye

Source: Bascuas T. et al., <a href="https://www.jove.com/v/62145">Isolation, Culture, and Genetic Engineering of Mammalian Primary Pigment Epithelial Cells for Non-Viral Gene Therapy.</a> J. Vis. Exp. (2021).
In this video we describe a technique to isolate iris and retinal pigment epithelial cells from porcine eyes to obtain their primary cultures for in vivo and ex vivo studies. These pigment cells could be genetically modified to study regenerative approaches to treat ocular disorders.

Source: Bascuas T. et al., Isolation, Culture, and Genetic Engineering of Mammalian Primary Pigment Epithelial Cells for Non-Viral Gene Therapy. J. Vis. ...

Isolation of Retinal Pigment Epithelial Cells from Guinea Pig Eyes

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