The authors would like to show their gratitude and respect to all animals contributing their cells in this study. This study was supported in part by grants from the National Key R&#38;D Program of China (2019YFA0111200, Yi Liao &#38; Yuan Gao and Grant nos. 2018YFA0107301, Wei Li). The authors thank Jingru Huang and Xiang You from Central Lab, School of Medicine, Xiamen University for technical support in confocal imaging.

The use of experimental animals complied with the regulations of the Association for Research in Vision and Ophthalmology (ARVO) and was approved by the Ethics Committee of Experimental Animal Management of Xiamen University.
1. Preparation of experimental surgical devices, tissue digestion enzyme, and cell culture buffer
<ol>
	<li>Prepare the experimental surgical devices, by cleaning and autoclaving two pairs of ophthalmic surgical scissors and forceps the day before the eyeball dissection, and afterward drying the box with surgical devices in a general protocol oven at 65 &#176;C overnight.</li>
	<li>Culture media preparation.
	<ol>
		<li>Prepare DMEM/Basic media supplemented with 10% (v/v) fetal bovine serum, 2 mM L-glutamine, and 1% (v/v) penicillin (100 U/mL) and streptomycin (100 U/mL).</li>
		<li>Prepare DMEM/F12 media supplemented with 1% (v/v) FBS, and 1% (v/v) penicillin (100 U/mL)&#160;and&#160;streptomycin (100 U/mL).</li>
		<li>Prepare MEM-Nic11, by supplementing MEM alpha with 2 mM L-glutamine, 1% FBS, 1% (v/v) penicillin (100 U/mL) and streptomycin (100 U/mL), 0.1 mM NEAA, 1% (v/v)&#160; N1 supplement, taurine (0.25 mg/mL), hydrocortisone (20 ng/mL), triiodo-thyronin (0.013 ng/mL), and 10 mM nicotinamide. 
		NOTE: To improve cell viability and proliferation, the percentage of FBS can be increased to 20% to neutralize digestion enzymes and seed the dissociated cells. For long-term cell culture, the percentage of FBS can be decreased to as low as 1%12.</li>
	</ol>
	</li>
	<li>Thaw the tissue digestion enzyme aliquot (0.25% (w/v) Trypsin/EDTA solution supplemented with 0.91 mM EDTA, hereafter referred as Trypsin/EDTA solution) during the experiment. 
	NOTE: Fresh Trypsin/EDTA solution should be used every time to obtain optimum results. Aliquot 10 mL of fresh Trypsin/EDTA solution into each 15 mL sterile centrifuge tube and freeze the aliquots at -20 &#176;C refrigerator until use.</li>
	<li>Dissection solution.
	<ol>
		<li>Sterilize 1x Phosphate Buffered Saline (PBS) (pH 7.2) supplemented with 2% (v/v) penicillin (100 U/mL) and streptomycin (100 U/mL) by filtering the solution through a 0.22 &#181;m syringe filter unit.</li>
	</ol>
	</li>
	<li>Coat the culture plates and transwell inserts.
	<ol>
		<li>Wash the wells and transwell inserts with 1x PBS. Remove the PBS from wells and transwells with a pipette, and then add 1 mL of fresh 1x PBS to the lower chamber and 600 &#181;L of 10 &#181;g/mL of laminin solution to the upper chamber.</li>
		<li>Incubate the plates/transwell inserts in the cell culture incubator overnight at 37 &#176;C and 5% CO2. Remove the laminin solution from the upper chamber and wash with 1 mL of cold 1x PBS twice before seeding the cells.</li>
	</ol>
	</li>
</ol>
2. Dissection of porcine eyeball RPE cells
<ol>
	<li>Preparation of the instruments.
	<ol>
		<li>Clean the laminar flow hood with 75% ethanol and UV light. Prepare three 50 mL sterile centrifuge tubes containing ~25 mL of 75% ethanol, three 50 mL sterile centrifuge tubes containing ~25 mL of 1x PBS, and three 10 cm sterile cell culture dishes containing ~15 mL of 1x PBS. 
		NOTE: These settings are usually used for dissecting four porcine eyeballs. Please scale up when more eyeballs are used. To improve the cell viability, precool 1x PBS buffer on ice for at least 30 min. Both 75% ethanol and UV light are necessary to ensure that experimental instruments and cells are not contaminated. Turn on the UV lamp in advance to sterilize the entire operation table for at least 15 min.</li>
	</ol>
	</li>
	<li>Clean the porcine eyeballs.
	<ol>
		<li>Obtain fresh eyeballs from a slaughterhouse and keep them on ice until dissection. Soak four porcine eyeballs into ~15 mL of 75% ethanol in a 10 cm Petri dish and use a pair of scissors and forceps to cut off all the residual connective tissues and muscles. 
		NOTE: Remove as much tissue as possible from outside of the sclera to reduce contaminations. Do not cut the optic nerve at this time to facilitate the transfer of eyeballs during the decontamination and wash step. After this step, all the procedures should be performed in a laminar flow hood.</li>
	</ol>
	</li>
	<li>Decontaminate the porcine eyeballs by soaking and washing four porcine eyeballs in three 50 mL sterile centrifuge tubes filled with 75% ethanol in a sequential manner; each eyeball is dipped for at least 5 min in each tube. Next, wash the porcine eyeballs in three 50 mL sterile centrifuge tubes filled with 1x PBS in a sequential manner; wash each eyeball for at least 5 min in each tube (Figure 1A). Invert the tubes every minute to wash the eyeballs thoroughly.</li>
	<li>Dissection of porcine eyeballs.
	<ol>
		<li>Move the four porcine eyeballs into a 10 cm sterile cell culture dish containing 1x PBS. Trim the outer surface of each eyeball again to remove the optic nerve and small debris (Figure 1B). Use scissors to make a small cut at the intersection of the limbus and sclera, and then remove the cornea, iris, lens, vitreous body, and neural retina (for detailed structures of these tissues, please refer to Figure 1).</li>
		<li>Transfer the RPE-choroid-sclera complex into a new 10 cm cell culture dish and make four cuts to flat the eyecup in the shape of a four-leaf clover (Figure 1C).</li>
	</ol>
	</li>
	<li>Perform Trypsin/EDTA solution digestion by placing the four RPE-choroid-sclera complexes into a new 10 cm dish. Pour 20 mL of fresh Trypsin/EDTA solution to merge the RPE-choroid-sclera complexes and put the dish into the cell culture incubator at 37 &#176;C for ~30 min. 
	&#8203;NOTE: Use fresh Trypsin/EDTA solution to dissociate the RPE cells. Carefully control the time of Trypsin/EDTA solution digestion, as a longer incubation time (more than 30 min) may increase the contamination of other types of cells.</li>
</ol>
3. Isolation and culture of porcine eyeball RPE cells
<ol>
	<li>RPE dissociation.
	<ol>
		<li>Take the dish out of the incubator after 30 min of incubation with Trypsin/EDTA solution and add 20 mL of prewarmed culture media (with 10% FBS) to the dish to neutralize the Trypsin/EDTA solution. 
		NOTE: At this step, only DMEM/Basic media is used. When cells reach confluency, three culture medias can be used depending on the experimental conditions: DMEM/Basic media, DMEM/F12 media, and MEM-Nic media.</li>
		<li>Use a 5 mL transfer pipette to dissociate the RPE cells by gently pipetting several times. Collect cell suspensions into 15 mL centrifuge tubes. Use another 10 mL of fresh culture media (10% FBS) to wash the RPE-choroid-sclera complexes on the dish by gently pipetting to obtain as many RPE cells as possible. 
		NOTE: Do not triturate the cells too vigorously. Ensure to fill and empty the pipette at a rate of about 3 mL/s. Avoid bubbling the cell suspension.</li>
	</ol>
	</li>
	<li>Collect RPE cells by centrifuging the tubes at 200 x g for 5 min at room temperature. Aspirate the supernatant using a pipette and add another 5 mL of culture media (10% FBS) to resuspend the cells and centrifuge at 200 x g for another 5 min. Decant the supernatant and resuspend the cells with 12 mL of culture media. 
	NOTE: When aspirating the supernatant, leave about 1 mL of media to avoid the breaking of cell clumps.</li>
	<li>Seeding RPE cells.
	<ol>
		<li>Seed ~1-2 x 105 cells/well into 12-well culture plates or transwell inserts. Usually, about 1.5 x 106 RPE cells are obtained from four porcine eyeballs. Change the culture media every 2 days and reduce the serum concentration to 1% when the cells fully cover the surface of the wells/inserts. 
		NOTE: Do not move the cell culture dish too frequently before cells attach to the culture dish/inserts.</li>
	</ol>
	</li>
	<li>Change the culture media every 2 days until the cells are harvested. 
	&#8203;NOTE: The concentration of FBS can be reduced after cells reach confluency, and cells can be cultured for up to several months to allow full differentiation and maturation.</li>
</ol>
4. Characterization of primary porcine RPE cells
<ol>
	<li>Culture the cells at confluency for 1 or 2 wks, and then harvest the cells for further analysis.</li>
	<li>Harvest cells for quantitative real-time PCR (qRT-PCR) analysis.
	<ol>
		<li>Remove the culture media, wash the cells with 1 mL of cold 1x PBS, and then add 500 &#181;L of RNA extraction solution into each well to collect cell lysate from about 1 x 106 cells.</li>
		<li>Extract mRNA13; approximately 4 &#181;g of RNA is extracted from each sample. Use 100 ng of mRNA to perform reverse transcription14; dilute the cDNA 40-fold for quantitative real-time PCR analysis. Primers are listed in Table 1.</li>
	</ol>
	</li>
	<li>Harvest cells for immunofluorescence staining.
	<ol>
		<li>Remove the culture media, wash the cells with 1 mL of cold 1x PBS, and then add 500 &#181;L of 4% (w/v) paraformaldehyde in 1x PBS to fix the cells (about 1 x 106 cells/well) for 30 min at room temperature. Then, wash the cells with 1x PBS twice and perform immunofluorescence staining with primary antibodies (1:100 in 1x PBS supplemented with 1% (w/v) bovine serum albumin) at 4 &#176;C overnight and secondary antibodies (1:200 in 1x PBS supplemented with 1% (w/v) bovine serum albumin) at room temperature for 2 h according to online protocols15.</li>
		<li>The immunofluorescence images are acquired by a confocal microscope following the online manual16.</li>
	</ol>
	</li>
	<li>Harvest cells for Western blot analysis.
	<ol>
		<li>Remove the culture media, wash the cells with cold 1x PBS twice, and then add 80 &#181;L of RIPA buffer (with 1x Protease inhibitor) into each well and use cell scrapers to scratch about 1 x 106 cells off the dishes/inserts.</li>
		<li>Collect the cell lysate from each well/insert into a 1.5 mL microcentrifuge tube. Boil the cell lysates for 10 min and then measure protein concentrations using BCA kits; the protein concentration of each sample is about 2 mg/mL. Use 25 &#181;g of proteins of each sample for Western blot analysis according to online protocols17.</li>
		<li>For Western blot, incubate the membranes in 5 mL of primary antibody solution (1:1,000 dilution of primary antibodies in 1x TBST solution supplemented with 5% (w/v) bovine serum albumin) at 4 &#176;C overnight on a rotating multipurpose shaker.</li>
		<li>Then, incubate the membrane with about 15 mL of anti-rabbit or anti-mouse secondary antibody solution (1:5,000 dilution of secondary antibodies in 1x TBST solution supplemented with 5% (w/v) non-fat milk) at room temperature for 2 h on an orbital shaker, according to the source of primary antibody used.</li>
	</ol>
	</li>
	<li>Transepithelial resistance (TER) measurement.
	<ol>
		<li>Wash the chopstick electrodes with 70% ethanol and sterile 1x PBS in a sequential way. Then place the shorter end of the electrode in the top chamber and the longer end in the bottom chamber of the transwell inserts and click the button on the epithelial voltmeter for the measurements. Record the TER measurements of each well in triplicates.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Tan, L. X., Germer, C. J., La Cunza, N., Lakkaraju, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Complement+activation,+lipid+metabolism,+and+mitochondrial+injury:+Converging+pathways+in+age-related+macular+degeneration.">Complement activation, lipid metabolism, and mitochondrial injury: Converging pathways in age-related macular degeneration.</a> Redox Biology. 37, 101781 (2020).</li><li>Caceres, P. S., Rodriguez-Boulan, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Retinal+pigment+epithelium+polarity+in+health+and+blinding+diseases.">Retinal pigment epithelium polarity in health and blinding diseases.</a> Current Opinion in Cell Biology. 62, 37-45 (2020).</li><li>Lakkaraju, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+cell+biology+of+the+retinal+pigment+epithelium.">The cell biology of the retinal pigment epithelium.</a> Progress in Retinal and Eye Research. 78, 100846 (2020).</li><li>Somasundaran, S., Constable, I. J., Mellough, C. B., Carvalho, L. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Retinal+pigment+epithelium+and+age-related+macular+degeneration:+A+review+of+major+disease+mechanisms.">Retinal pigment epithelium and age-related macular degeneration: A review of major disease mechanisms.</a> Clinical &amp; Experimental Ophthalmology. 48 (8), 1043-1056 (2020).</li><li>Ducloyer, J. B., Le Meur, G., Cronin, T., Adjali, O., Weber, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gene+therapy+for+retinitis+pigmentosa.">Gene therapy for retinitis pigmentosa.</a> Medecine Sciences. 36 (6-7), 607-615 (2020).</li><li>den Hollander, A. I., Roepman, R., Koenekoop, R. K., Cremers, F. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Leber+congenital+amaurosis:+genes,+proteins+and+disease+mechanisms.">Leber congenital amaurosis: genes, proteins and disease mechanisms.</a> Progress in Retinal and Eye Research. 27 (4), 391-419 (2008).</li><li>Samuels, I. S., Bell, B. A., Pereira, A., Saxon, J., Peachey, N. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+retinal+pigment+epithelium+dysfunction+is+concomitant+with+hyperglycemia+in+mouse+models+of+type+1+and+type+2+diabetes.">Early retinal pigment epithelium dysfunction is concomitant with hyperglycemia in mouse models of type 1 and type 2 diabetes.</a> Journal of Neurophysiology. 113 (4), 1085-1099 (2015).</li><li>Smith, D. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Melanin+pigment+in+the+pigmented+epithelium+of+the+retina+of+the+embryo+chick+eye+studied+in+vivo+and+in+vino.">Melanin pigment in the pigmented epithelium of the retina of the embryo chick eye studied in vivo and in vino.</a> The Anatomical Record. 18, 260-261 (1920).</li><li>Schnichels, 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=Retina+in+a+dish:+Cell+cultures,+retinal+explants+and+animal+models+for+common+diseases+of+the+retina.">Retina in a dish: Cell cultures, retinal explants and animal models for common diseases of the retina.</a> Progress in Retinal and Eye Research. 81, 100880 (2021).</li><li>D'Antonio-Chronowska, A., D'Antonio, M., Frazer, K. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+differentiation+of+human+iPSC-derived+retinal+pigment+epithelium+cells+(iPSC-RPE).">In vitro differentiation of human iPSC-derived retinal pigment epithelium cells (iPSC-RPE).</a> Bio-Protocol. 9 (24), 3469 (2019).</li><li>Hazim, R. A., Volland, S., Yen, A., Burgess, B. L., Williams, D. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+differentiation+of+the+human+RPE+cell+line,+ARPE-19,+induced+by+nicotinamide.">Rapid differentiation of the human RPE cell line, ARPE-19, induced by nicotinamide.</a> Experimental Eye Research. 179, 18-24 (2019).</li><li>Dunn, K. C., Aotaki-Keen, A. E., Putkey, F. R., Hjelmeland, L. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ARPE-19,+a+human+retinal+pigment+epithelial+cell+line+with+differentiated+properties.">ARPE-19, a human retinal pigment epithelial cell line with differentiated properties.</a> Experimental Eye Research. 62 (2), 155-169 (1996).</li><li>. Scientific, T Available from: <a target="_blank" href="https://www.thermofisher.cn/document-connect/document">https://www.thermofisher.cn/document-connect/document</a> (2022)</li><li>. Toyota Available from: <a target="_blank" href="https://www.toyoboglobal.com/seihin/xr/likescience/support/manual/FSQ-201.pdf">https://www.toyoboglobal.com/seihin/xr/likescience/support/manual/FSQ-201.pdf</a> (2022)</li><li>. Abcam Available from: <a target="_blank" href="https://www.abcam.cn/protocols/immunocytochemistry-immunofluorescence-protocol">https://www.abcam.cn/protocols/immunocytochemistry-immunofluorescence-protocol</a> (2022)</li><li>. Zeiss Available from: <a target="_blank" href="https://www.zeiss.com/microscopy/en/products/software/zeiss-zen-lite.html#manuals">https://www.zeiss.com/microscopy/en/products/software/zeiss-zen-lite.html#manuals</a> (2022)</li><li>. Cell Signal Technology Available from: <a target="_blank" href="https://www.cellsignal.cn/learn-and-support/protocols/protocol-western">https://www.cellsignal.cn/learn-and-support/protocols/protocol-western</a> (2022)</li><li>Wang, 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=Reversed+senescence+of+retinal+pigment+epithelial+cell+by+coculture+with+embryonic+stem+cell+via+the+TGFbeta+and+PI3K+pathways.">Reversed senescence of retinal pigment epithelial cell by coculture with embryonic stem cell via the TGFbeta and PI3K pathways.</a> Frontiers in Cell and Developmental Biology. 8, 588050 (2020).</li><li>Pfeffer, B. A., Philp, N. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+culture+of+retinal+pigment+epithelium:+Special+Issue.">Cell culture of retinal pigment epithelium: Special Issue.</a> Experimental Eye Research. 126, 1-4 (2014).</li><li>Lehmann, G. L., Benedicto, I., Philp, N. J., Rodriguez-Boulan, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasma+membrane+protein+polarity+and+trafficking+in+RPE+cells:+past,+present+and+future.">Plasma membrane protein polarity and trafficking in RPE cells: past, present and future.</a> Experimental Eye Research. 126, 5-15 (2014).</li><li>Anderson, J. M., Van Itallie, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physiology+and+function+of+the+tight+junction.">Physiology and function of the tight junction.</a> Cold Spring Harbor Perspectives in Biology. 1 (2), 002584 (2009).</li><li>Nita, M., Strzalka-Mrozik, B., Grzybowski, A., Mazurek, U., Romaniuk, 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+and+changes+in+the+extracellular+matrix.">Age-related macular degeneration and changes in the extracellular matrix.</a> Medical Science Monitor. 20, 1003-1016 (2014).</li><li>Fernandez-Godino, R., Garland, D. L., Pierce, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation,+culture+and+characterization+of+primary+mouse+RPE+cells.">Isolation, culture and characterization of primary mouse RPE cells.</a> Nature Protocols. 11 (7), 1206-1218 (2016).</li><li>Langenfeld, A., Julien, S., Schraermeyer, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+improved+method+for+the+isolation+and+culture+of+retinal+pigment+epithelial+cells+from+adult+rats.">An improved method for the isolation and culture of retinal pigment epithelial cells from adult rats.</a> Graefe's Archive for Clinical and Experimental Ophthalmology. 253 (9), 1493-1502 (2015).</li><li>Sonoda, S. <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></ol>

All the authors disclosed that there are no conflicts of interest.
All the authors declare no competing financial interests.

Here, a detailed and optimized protocol for the isolation, culture, and characterization of RPE cells from porcine eyeballs, which generates a good model for in vitro characterization of RPE cells and RPE-related disorder studies has been described. Methods for the isolation of the RPE from human, mouse, and rat eyes have been described previously23,24,25. However, it is difficult to obtain human eyeballs in some labora...

The retinal pigment epithelium (RPE) is located between photoreceptors and choriocapillaris in the outer layer of the retina1 with multiple functions, including forming the blood-retinal barrier, transporting and exchanging nutrients and retinal metabolites, recycling vitamin A to maintain a normal visual cycle, and phagocytosis and clearance of shed photoreceptor outer segments (POSs)2,3. Since POSs require constant self-renewal to generate vision, the RPE cells need to continuously engulf detached POSs to maintain retinal homeostasis4. Therefore, RPE dysfunction results in many blinding eye diseases, such as age-related macular degeneration (AMD)4, retinitis pigmentosa (RP)5,&#160;Leber congenital amaurosis6, diabetic retinopathy7, etc. Till now, the exact pathogenesis of most of these diseases remains elusive. As a result, RPE cell culture is established to study RPE cell biology, pathological changes, and underlying mechanisms.
As the simplest model to study cell biology, the culture of RPE cells was started as early as the 1920s8. Although ARPE-19 is widely used as RPE cells, loss of pigmentation, cobblestone morphology, and, especially, the barrier functions in this cell line raise lots of concerns9. In comparison, the culture of primary human RPE cells offers a more realistic scenario for physiological and pathological studies9. However, the relatively limited availability restricts their usage and ethical issues always exist. In addition, several groups used mouse models to culture RPE cells. However, the size of the mouse eye is small, and a single culture usually requires many mice, which is not convenient9. Recently, scientists have developed new methods to use human embryonic stem cells or induced pluripotent stem cells to derive RPE cells. Although this technique has particular potential for the treatment of inherited RPE disorders, it is time-consuming and usually requires several months to generate mature RPE cells10. To overcome these problems, here we introduce an easy-to-follow protocol to isolate and culture high-purity RPE cells in the laboratory routinely. Under suitable culture conditions, these cells can display typical RPE functions and exhibit typical RPE morphologies. Therefore, this culture method can provide a good model to understand RPE physiology, study cytotoxicity, investigate pathological mechanisms of related ocular diseases, and conduct drug screenings.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>ARPE-19 cells</td>
			<td>CCTCC</td>
			<td>GDC0323</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine serum albumin</td>
			<td>Yeasen</td>
			<td>36101ES60</td>
			<td></td>
		</tr>
		<tr>
			<td>Confocal microscopy</td>
			<td>Zeiss</td>
			<td>LSM 880 with Airyscan</td>
			<td></td>
		</tr>
		<tr>
			<td>ChemiDoc Touch</td>
			<td>Bio-Rad</td>
			<td>1708370</td>
			<td></td>
		</tr>
		<tr>
			<td>Cell scraper</td>
			<td>Sangon</td>
			<td>F619301</td>
			<td></td>
		</tr>
		<tr>
			<td>10 cm culture dish</td>
			<td>NEST</td>
			<td>121621EH01</td>
			<td></td>
		</tr>
		<tr>
			<td>12-well culture plate</td>
			<td>NEST</td>
			<td>29821075P</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM F12 Medium</td>
			<td>Gibco</td>
			<td>C11330500BT</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM basic Medium</td>
			<td>Gibco</td>
			<td>C11995500BT</td>
			<td></td>
		</tr>
		<tr>
			<td>EVOM2</td>
			<td>World Precision Instruments</td>
			<td>EVOM2</td>
			<td>For TER measurement</td>
		</tr>
		<tr>
			<td>Fetal bovine serum</td>
			<td>ExCell Bio</td>
			<td>FSP500</td>
			<td></td>
		</tr>
		<tr>
			<td>Goat anti-Rabbit IgG (H+L) Highly Cross-Adsorbed Secondary Antibody, Alexa Fluor 488</td>
			<td>ThermoFisher Scientific&#160;</td>
			<td>A-11034</td>
			<td></td>
		</tr>
		<tr>
			<td>Goat anti-Rabbit IgG (H+L) Cross-Adsorbed Secondary Antibody, Alexa Fluor 594</td>
			<td>ThermoFisher Scientific</td>
			<td>A-11012</td>
			<td></td>
		</tr>
		<tr>
			<td>Goat anti Mouse IgG (H/L):HRP</td>
			<td>Bio-Rad</td>
			<td>0300-0108P</td>
			<td></td>
		</tr>
		<tr>
			<td>Goat anti Rabbit IgG (H/L):HRP</td>
			<td>Bio-Rad</td>
			<td>5196-2504</td>
			<td></td>
		</tr>
		<tr>
			<td>hydrocortisone</td>
			<td>MCE</td>
			<td>HY-N0583/CS-2226</td>
			<td></td>
		</tr>
		<tr>
			<td>Hoechst 33342 solution (20 mM)</td>
			<td>ThermoFisher Scientific</td>
			<td>62249</td>
			<td></td>
		</tr>
		<tr>
			<td>LightCycler 96 Instrument</td>
			<td>Roche</td>
			<td>5815916001</td>
			<td></td>
		</tr>
		<tr>
			<td>Liothyronine</td>
			<td>MCE</td>
			<td>HY-A0070A/CS-4141</td>
			<td></td>
		</tr>
		<tr>
			<td>laminin</td>
			<td>Sigma-Aldrich</td>
			<td>L2020-1MG</td>
			<td></td>
		</tr>
		<tr>
			<td>MEM(1X)+GlutaMAX Medium</td>
			<td>Gibco</td>
			<td>10566-016</td>
			<td></td>
		</tr>
		<tr>
			<td>MEM NEAA(100X)</td>
			<td>Gibco</td>
			<td>11140-050</td>
			<td></td>
		</tr>
		<tr>
			<td>Millex-GP syringe filter unit</td>
			<td>Millipore</td>
			<td>SLGPR33RB</td>
			<td></td>
		</tr>
		<tr>
			<td>N1</td>
			<td>Sigma-Aldrich</td>
			<td>SLCF4683</td>
			<td></td>
		</tr>
		<tr>
			<td>NcmECL Ultra</td>
			<td>New Cell&#38;Molecular Biotech</td>
			<td>P10300</td>
			<td></td>
		</tr>
		<tr>
			<td>Non-fat Powdered Milk</td>
			<td>Solarbio</td>
			<td>D8340</td>
			<td></td>
		</tr>
		<tr>
			<td>Nicotinamide</td>
			<td>SparkJade</td>
			<td>SJ-MV0061</td>
			<td></td>
		</tr>
		<tr>
			<td>Na+-K+ ATPase antibody</td>
			<td>Abcam</td>
			<td>ab76020</td>
			<td>Recognize both human and porcine proteins</td>
		</tr>
		<tr>
			<td>PAGE Gel Fast Preparation Kit(10%)</td>
			<td>Epizyme</td>
			<td>PG112</td>
			<td></td>
		</tr>
		<tr>
			<td>primary Human RPE cells&#160;</td>
			<td>-</td>
			<td>-</td>
			<td>Generous gift from Shoubi Wang lab&#160;</td>
		</tr>
		<tr>
			<td>Pierce BCA Protein Assay Kit&#160;</td>
			<td>ThermoFisher Scientific</td>
			<td>23225</td>
			<td></td>
		</tr>
		<tr>
			<td>Prism</td>
			<td>GraphPad by Dotmatics</td>
			<td>version 8.0</td>
			<td></td>
		</tr>
		<tr>
			<td>Protease Inhibitor Cocktails</td>
			<td>APExBIO</td>
			<td>K1024</td>
			<td></td>
		</tr>
		<tr>
			<td>PRE65 antibody</td>
			<td>Proteintech</td>
			<td>17939-1-AP</td>
			<td>Recognize both human and porcine proteins</td>
		</tr>
		<tr>
			<td>PEDF antibody</td>
			<td>Santa Cruz Biotechnology</td>
			<td>sc-390172</td>
			<td>Recognize both human and porcine proteins</td>
		</tr>
		<tr>
			<td>100 x penicillin/streptomycin&#160;</td>
			<td>Biological Industries</td>
			<td>03-031-1BCS</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate buffered saline (PBS)</td>
			<td>RARBIO</td>
			<td>RA-9005</td>
			<td></td>
		</tr>
		<tr>
			<td>ReverTra Ace qPCR RT Master Mix</td>
			<td>Toyobo</td>
			<td>FSQ-201</td>
			<td></td>
		</tr>
		<tr>
			<td>RIPA buffer</td>
			<td>ThermoFisher Scientific&#160;</td>
			<td>89900</td>
			<td></td>
		</tr>
		<tr>
			<td>15 mL sterile centrifuge tubes</td>
			<td>NEST</td>
			<td>601052</td>
			<td></td>
		</tr>
		<tr>
			<td>50 mL sterile centrifuge tubes</td>
			<td>NEST</td>
			<td>602052</td>
			<td></td>
		</tr>
		<tr>
			<td>0.25% Trypsin-EDTA</td>
			<td>Gibco</td>
			<td>25200-056</td>
			<td></td>
		</tr>
		<tr>
			<td>Taurine</td>
			<td>Damas-beta</td>
			<td>107-35-7</td>
			<td></td>
		</tr>
		<tr>
			<td>Trizol</td>
			<td>Thermo-Fisher&#160;</td>
			<td>15596026</td>
			<td>RNA extraction solution</td>
		</tr>
		<tr>
			<td>TB Green Fast qPCR Mix</td>
			<td>Takara</td>
			<td>RR430A</td>
			<td></td>
		</tr>
		<tr>
			<td>12-well transwell inserts</td>
			<td>Labselect</td>
			<td>14212</td>
			<td></td>
		</tr>
		<tr>
			<td>VEGF antibody</td>
			<td>Proteintech</td>
			<td>19003-1-AP</td>
			<td>Recognize both human and porcine proteins</td>
		</tr>
		<tr>
			<td>VEGF ELISA kit</td>
			<td>Novusbio</td>
			<td>VAL106</td>
			<td></td>
		</tr>
		<tr>
			<td>ZO-1 antibody</td>
			<td>ABclonal</td>
			<td>A0659</td>
			<td>Recognize both human and porcine proteins</td>
		</tr>
	</tbody>
</table>

primary culture of porcine retinal pigment epithelial cells

The retinal pigment epithelium (RPE) is a monolayer of polarized pigmented epithelial cells, located between the choroid and neuroretina in the retina. Multiple functions, including phagocytosis, nutrient/metabolite transportation, vitamin A metabolism, etc., are conducted by the RPE on a daily basis. RPE cells are terminally differentiated epithelial cells with little or no regenerative capacity. Loss of RPE cells results in multiple eye diseases leading to visual impairment, such as age-related macular degeneration. Therefore, the establishment of an in vitro culture model of primary RPE cells, which more closely resembles the RPE in vivo than cell lines, is critical for the characteristic and mechanistic studies of RPE cells. Considering the fact that the source of human eyeballs is limited, we create a protocol to culture primary porcine RPE cells. By using this protocol, RPE cells can be easily dissociated from adult porcine eyeballs. Subsequently, these dissociated cells attach to culture dishes/inserts, proliferate to form a confluent monolayer, and quickly re-establish key features of epithelial tissue in vivo within 2 wks. By qRT-PCR, it is demonstrated that primary porcine RPE cells express multiple signature genes at comparable levels with native RPE tissue, while the expressions of most of these genes are lost/highly reduced in human RPE-like cells, ARPE-19. Moreover, the immunofluorescence staining shows the distribution of tight junction, tissue polarity, and cytoskeleton proteins, as well as the presence of RPE65, an isomerase critical for vitamin A metabolism, in cultured primary cells. Altogether, we have developed an easy-to-follow approach to culture primary porcine RPE cells with high purity and native RPE features, which could serve as a good model to understand RPE physiology, study cell toxicities, and facilitate drug screenings.

The primary porcine RPE (pRPE) cells were cultured in DMEM/Basic media with 10% FBS, and cell morphology under light microscope was photographed at 2 days (Figure 2A), 6 days (Figure 2B) and 10 days (Figure 2C) after seeding. After 1 wk, a confluent monolayer of pigmented pRPE cells with cobblestone morphologies was observed.
To better characterize the primary pRPE cells, primary human RPE cells (hRPE) at...

Watch this Scientific Journal Video about Primary Culture of Porcine Retinal Pigment Epithelial Cells at JoVE.com

Primary Culture of Porcine Retinal Pigment Epithelial Cells

Here, an easy-to-follow method to culture primary porcine retinal pigment epithelial cells in vitro is presented.

The retinal pigment epithelium (RPE) is a monolayer of polarized pigmented epithelial cells, located between the choroid and neuroretina in the retina. ...

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2.0K Views.  Xiamen University. Here, an easy-to-follow method to culture primary porcine retinal pigment epithelial cells in vitro is presented. 

Video: Primary Culture of Porcine Retinal Pigment Epithelial Cells

Ex Vivo Culture of Primary Human Fallopian Tube Epithelial Cells

Epithelial ovarian cancer is a leading cause of female cancer mortality in the United States. In contrast to other women-specific cancers, like breast and uterine carcinomas, where death rates have fallen in recent years, ovarian cancer cure rates have remained relatively unchanged over the past two decades 1. This is largely due to the lack of appropriate screening tools for detection of early stage disease where surgery and chemotherapy are most effective 2, 3. As a result, most patients present with advanced stage disease and diffuse abdominal involvement. This is further complicated by the fact that ovarian cancer is a heterogeneous disease with multiple histologic subtypes 4, 5. Serous ovarian carcinoma (SOC) is the most common and aggressive subtype and the form most often associated with mutations in the BRCA genes. Current experimental models in this field involve the use of cancer cell lines and mouse models to better understand the initiating genetic events and pathogenesis of disease 6, 7. Recently, the fallopian tube has emerged as a novel site for the origin of SOC, with the fallopian tube (FT) secretory epithelial cell (FTSEC) as the proposed cell of origin 8, 9. There are currently no cell lines or culture systems available to study the FT epithelium or the FTSEC. Here we describe a novel ex vivo culture system where primary human FT epithelial cells are cultured in a manner that preserves their architecture, polarity, immunophenotype, and response to physiologic and genotoxic stressors. This ex vivo model provides a useful tool for the study of SOC, allowing a better understanding of how tumors can arise from this tissue, and the mechanisms involved in tumor initiation and progression.

Ex Vivo Culture of Primary Human Fallopian Tube Epithelial Cells

The fallopian tube (FT) is emerging as an alternative site of origin for serous ovarian carcinoma (SOC). This protocol describes a novel method for the isolation and ex vivo culture of fallopian tube epithelial cells. This system recapitulates the in vivo epithelium and allows the study of SOC pathogenesis.

Epithelial ovarian cancer is a leading cause of female cancer mortality in the United States. In contrast to other women-specific cancers, like breast and ...

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, ...

Subretinal Transplantation of Human Embryonic Stem Cell Derived-retinal Pigment Epithelial Cells into a Large-eyed Model of Geographic Atrophy

Geographic atrophy (GA), the late stage of dry age-related macular degeneration is characterized by loss of the retinal pigment epithelial (RPE) layer, which leads to subsequent degeneration of vital retinal structures (e.g., photoreceptors) causing severe vision impairment. Similarly, RPE-loss and decrease in visual acuity is seen in long-term follow up of patients with advanced wet age-related macular degeneration (AMD) receiving intravitreal anti-vascular endothelial growth factor (VEGF) treatment. Therefore, on the one hand, it is fundamental to efficiently derive RPE cells from an unlimited source that could serve as replacement therapy. On the other hand, it is important to assess the behavior and integration of the derived cells in a model of the disease entailing surgical and imaging methods as close as possible to those applied in humans. Here, we provide a detailed protocol based on our previous publications that describes the generation of a preclinical model of GA using the albino rabbit eye, for evaluation of the human embryonic stem cell derived retinal pigment epithelial cells (hESC-RPE) in a clinically relevant setting. Differentiated hESC-RPE are transplanted into naive eyes or eyes with NaIO3-induced GA-like retinal degeneration using a 25 G transvitreal pars plana technique. Evaluation of degenerated and transplanted areas is performed by multimodal high-resolution non-invasive real-time imaging.

Retinal pigment epithelial cells could serve as a cell-replacement therapy for the advanced form of dry age-related macular degeneration. This protocol describes the generation of a large-eyed model of geographic atrophy and the subretinal transplantation of human embryonic stem cell-derived retinal pigment epithelial cells into this model of disease.

Geographic atrophy (GA), the late stage of dry age-related macular degeneration is characterized by loss of the retinal pigment epithelial (RPE) layer, ...

Primary Cell Cultures from the Mouse Retinal Pigment Epithelium

The retinal pigment epithelium (RPE) is a highly polarized multi-functional epithelium that is located between the neural retina and the choroid of the eye. It is a single sheet of pigmented cells that are hexagonally packed and connected by tight junctions. The main functions of the RPE include absorption of light, phagocytosis of the shed photoreceptor outer segments, spatial buffering of ions, transport of nutrients, ions and water as well as active involvement in the visual cycle. With such important and diverse functions, it is critically important to study the biology of RPE cells. A number of RPE cell lines have been established; however, passaged and immortalized cells are known to quickly lose some of the morphological and physiological characteristics of natural RPE cells. Thus, primary cells are more suitable for studying different aspects of RPE cell biology and function. Mouse primary RPE cell culture is very useful to researchers since mouse models are widely used in biological studies, however collecting RPE cells from mouse is also very challenging due to their small size. Here, we present a protocol for establishing primary mouse RPE cell cultures which includes enucleation and dissection of the eyes and isolation of the RPE sheets to yield the cells for culturing. This method enables efficient cell recovery. The RPE cells obtained from two mice&#160;can reach confluency on one 12 mm polyester membrane insert pre-loaded in culture plate after one week of culture and display some of the original properties of bona fide RPE cells such as hexagonal shape and pigmentation after two weeks of culture.

The retinal pigment epithelium (RPE) is a multi-functional epithelium of the eye. Here we present a protocol to establish primary cell cultures derived from the murine RPE.

The retinal pigment epithelium (RPE) is a highly polarized multi-functional epithelium that is located between the neural retina and the choroid of the ...

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 ...

Efficient Dissection and Culture of Primary Mouse Retinal Pigment Epithelial Cells

Eye disorders affect millions of people worldwide, but the limited availability of human tissues hinders their study. Mouse models are powerful tools to understand the pathophysiology of ocular diseases because of their similarities with human anatomy and physiology. Alterations in the retinal pigment epithelium (RPE), including changes in morphology and function, are common features shared by many ocular disorders. However, successful isolation and culture of primary mouse RPE cells is very challenging. This paper is an updated audiovisual version of the protocol previously published by Fernandez-Godino et al. in 2016 to efficiently isolate and culture primary mouse RPE cells. This method is highly reproducible and results in robust cultures of highly polarized and pigmented RPE monolayers that can be maintained for several weeks on Transwells. This model opens new avenues for the study of the molecular and cellular mechanisms underlying eye diseases. Moreover, it provides a platform to test therapeutic approaches that can be used to treat important eye diseases with unmet medical needs, including inherited retinal disorders and macular degenerations.

This protocol, which was originally reported by Fernandez-Godino et al. in 20161, describes a method to efficiently isolate and culture mouse RPE cells, which form a functional and polarized RPE monolayer within one week on Transwell plates. The procedure takes approximately 3 hours.

Eye disorders affect millions of people worldwide, but the limited availability of human tissues hinders their study. Mouse models are powerful tools to ...

Real-Time Analysis of Bioenergetics in Primary Human Retinal Pigment Epithelial Cells Using High-Resolution Respirometry

Metabolic dysfunction of retinal pigment epithelial cells (RPE) is a key pathogenic driver of retinal diseases such as age-related macular degeneration (AMD) and proliferative vitreoretinopathy (PVR). Since RPE are highly metabolically-active cells, alterations in their metabolic status reflect changes in their health and function. High-resolution respirometry allows for real-time kinetic analysis of the two major bioenergetic pathways, glycolysis and mitochondrial oxidative phosphorylation (OXPHOS), through quantification of the extracellular acidification rate (ECAR) and oxygen consumption rate (OCR), respectively. The following is an optimized protocol for conducting high-resolution respirometry on primary human retinal pigment epithelial cells (H-RPE). This protocol provides a detailed description of the steps involved in producing bioenergetic profiles of RPE to define their basal and maximal OXPHOS and glycolytic capacities. Exposing H-RPE to different drug injections targeting the mitochondrial and glycolytic machinery results in defined bioenergetic profiles, from which key metabolic parameters can be calculated. This protocol highlights the enhanced response of BAM15 as an uncoupling agent compared to carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) to induce the maximal respiration capacity in RPE. This protocol can be utilized to study the bioenergetic status of RPE under different disease conditions and test the efficacy of novel drugs in restoring the basal metabolic status of RPE.

The metabolic status of human retinal pigment epithelial cells (H-RPE) reflects their health and function. Presented here is an optimized protocol for examining the real-time metabolic flux of H-RPE using high-resolution respirometry.

Metabolic dysfunction of retinal pigment epithelial cells (RPE) is a key pathogenic driver of retinal diseases such as age-related macular degeneration ...

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.

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 ...

Protocol for Isolating Mammary Epithelial Cells from Human Tissue

Isolation and Culture of Primary Human Mammary Epithelial Cells

The mammary gland is a fundamental structure of the breast and plays an essential role in reproduction. Human mammary epithelial cells (HMECs), which are the origin cells of breast cancer and other breast-related inflammatory diseases, have garnered considerable attention. However, isolating and culturing primary HMECs in vitro for research purposes has been challenging due to their highly differentiated, keratinized nature and their short lifespan. Therefore, developing a simple and efficient method to isolate and culture HMECs is of great scientific value for the study of breast biology and breast-related diseases. In this study, we successfully isolated primary HMECs from small amounts of mammary tissue by digestion with a mixture of enzymes combined with an initial culture in 5% fetal bovine serum-DMEM containing the Rho-associated kinase (ROCK) inhibitor Y-27632, followed by culture expansion in serum-free keratinocyte medium. This approach selectively promotes the growth of epithelial cells, resulting in an optimized cell yield. The simplicity and convenience of this method make it suitable for both laboratory and clinical research, which should provide valuable insights into these important areas of study.

Author Spotlight: Integrating Eastern and Western Medicine for Treatment of Granulomatous Mastitis

The present study reports an easier, time-saving, and economical protocol to efficiently isolate and grow primary human mammary epithelial cells (HMECs) from small amounts of mammary tissue. This protocol is suitable for quickly producing primary HMECs both for laboratory and clinical applications.

The mammary gland is a fundamental structure of the breast and plays an essential role in reproduction. Human mammary epithelial cells (HMECs), which are ...

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 ...