Name: a novel human epithelial enteroid model of necrotizing enterocolitis
Uploaded: 2019-04-10T13:00:00
Description: Watch this Scientific Journal Video about A Novel Human Epithelial Enteroid Model of Necrotizing Enterocolitis at JoVE.com

This work was supported by the National Institute of Health Institute of Diabetes and Digestive and Kidney Disease Grant (K08DK106450) and the Jay Grosfeld Award from the American Pediatric Surgical Association to C.J.H.

Institutional review board approval was obtained (IRB #2013-15152) for collection of tissue samples from patients undergoing bowel resection at Ann and Robert H. Lurie Children&#39;s Hospital of Chicago, Chicago, IL. All protocols were performed in compliance with institutional and national guidelines and regulations for human welfare. Written informed parental consent was required and obtained prior to sample collection in all cases.
1. Reagent Preparation
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	<li>Prepare Culture Media st...

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G., 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=Human+mini-guts:+new+insights+into+intestinal+physiology+and+host-pathogen+interactions.">Human mini-guts: new insights into intestinal physiology and host-pathogen interactions.</a> Nature Reviews Gastroenterology &amp; Hepatology. 13 (11), 633-642 (2016).</li><li>Senger, 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=Human+Fetal-Derived+Enterospheres+Provide+Insights+on+Intestinal+Development+and+a+Novel+Model+to+Study+Necrotizing+Enterocolitis+(NEC).">Human Fetal-Derived Enterospheres Provide Insights on Intestinal Development and a Novel Model to Study Necrotizing Enterocolitis (NEC).</a> Cell and Molecular Gastroenterology and Hepatology. 5 (4), 549-568 (2018).</li><li>Moore, S. 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=Intestinal+barrier+dysfunction+in+human+necrotizing+enterocolitis.">Intestinal barrier dysfunction in human necrotizing enterocolitis.</a> Journal of Pediatric Surgery. 51 (12), 1907-1913 (2016).</li><li>Neal, M. 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=A+critical+role+for+TLR4+induction+of+autophagy+in+the+regulation+of+enterocyte+migration+and+the+pathogenesis+of+necrotizing+enterocolitis.">A critical role for TLR4 induction of autophagy in the regulation of enterocyte migration and the pathogenesis of necrotizing enterocolitis.</a> The Journal of Immunology. 190 (7), 3541-3551 (2013).</li><li>Lanik, W. 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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=Enterocyte+TLR4+mediates+phagocytosis+and+translocation+of+bacteria+across+the+intestinal+barrier.">Enterocyte TLR4 mediates phagocytosis and translocation of bacteria across the intestinal barrier.</a> The Journal of Immunology. 176 (5), 3070-3079 (2006).</li><li>Sodhi, C. P., 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=Intestinal+epithelial+Toll-like+receptor+4+regulates+goblet+cell+development+and+is+required+for+necrotizing+enterocolitis+in+mice.">Intestinal epithelial Toll-like receptor 4 regulates goblet cell development and is required for necrotizing enterocolitis in mice.</a> Gastroenterology. 143 (3), 708-718 (2012).</li><li>Koo, B. 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This novel ex vivo human intestinal enteroid model serves as a useful method for the study of intestinal barrier dysfunction in necrotizing enterocolitis (NEC). The enteroid processing methods presented here were adapted from the previous work of Drs. Misty Good, Michael Helmrath and Jason Wertheim10,11,12.
Details surrounding the whole tissue collection and timing of crypt isolation are critical step...

Human enteroids are an ex vivo 3-dimensional culture system generated from stem cells isolated from intestinal crypts of human intestinal tissue samples. This ground-breaking model was pioneered by Hans Clevers et al. in 2007 following the discovery of Lgr5+ stem cells at the crypts of small intestine in mice1. Their work laid the foundation for establishing an ex vivo intestinal epithelial culture of multiple cell types that could be passaged without significant genetic or physiologic changes2. Since this discovery, enteroids have been used as a novel model to study normal digestive physiology, and the pathophysiology of intestinal diseases such as inflammatory bowel disease, host-pathogen interactions, and regenerative medicine2.
The use of enteroids as an ex vivo model for the study of intestinal pathophysiology has several advantages over alternative techniques. For the past several decades, animal models and immortalized intestinal cancer-derived cell lines have been used to study intestinal physiology3,4,5. Single-cell cultures do not represent the diversity of cell types present in normal intestinal epithelium, thereby lacking cell to cell cross-talk and segment-specificity in protein expression, signaling, and pathogen-induced disease6. Stem cells in enteroids differentiate into the major epithelial cell types such as enterocytes, Paneth cells, goblet cells, enteroendocrine cells and more3. They exhibit polarity, carry out epithelial transport functions, and allow for intestinal segment specificity6. Since enteroids can recapitulate the multiple cell types of human intestinal epithelium, they are able to overcome this recognized limitation of cancer cell-based systems. Over time, derivatives of cell lines are subcloned and evolve to exhibit greater diversity in protein expression and localization3. On the contrary, enteroids can be passaged without significant genetic or physiologic changes2. Although numerous animal models for NEC exist, response to injury and therapeutic interventions may be highly variable between species. As a result of these limitations, therapeutics derived from animal models fail 90% of the time when tested in human trials due to differences in toxicity or efficacy3. Enteroids serve as promising pre-clinical models that can overcome these deficiencies, leading to a better understanding of complex intestinal pathophysiology and therefore, more successful and cost-effective therapeutic innovations. There is also recent evidence that the age of the tissue that an enteroid is generated from remains biologically important7. This is an especially important detail for our model since enteroids are generated from neonatal tissue, thereby maintaining physiologic relevance to patients with NEC.
The utility of enteroids as models of human illnesses continues to expand, in hopes of finding cures to severe and pervasive conditions. Necrotizing enterocolitis (NEC) is a devastating intestinal disease of neonates characterized by intestinal necrosis and frequently leads to perforation of the bowel wall, septicemia, and death8. Due to the complex and multifactorial pathophysiology of NEC, the exact mechanism of the disease has not yet been fully elucidated; however, increased intestinal permeability has been clearly implicated in the disease process8. Given that the study of NEC and potential therapeutic agents is ethically challenging in human subjects, especially children, it is highly desirable to utilize a biologically relevant enteroid model of NEC using human neonatal tissue. Thus far, enteroids have a limited role in the study of NEC. This protocol describes the use of enteroids derived from human intestinal tissue samples as a novel ex vivo model for the study of necrotizing enterocolitis.

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			<td height="21" style="height:21px;width:415px;">4% Paraformaldehyde</td>
			<td style="width:139px;">ThermoFisher</td>
			<td style="width:167px;">AAJ19943K2</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">A-83</td>
			<td style="width:139px;">R&#38;D Tocris</td>
			<td style="width:167px;">2939/10</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">Amphotericin B</td>
			<td style="width:139px;">ThermoFisher</td>
			<td style="width:167px;">15290026</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">B-27 supplement minus Vitamin A</td>
			<td style="width:139px;">ThermoFisher</td>
			<td style="width:167px;">17504-044</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">Basement Membrane Matrix (Matrigel)</td>
			<td style="width:139px;">Corning</td>
			<td style="width:167px;">CB-40230C</td>
			<td></td>
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			<td height="21" style="height:21px;width:415px;">DMEM/F-12</td>
			<td style="width:139px;">ThermoFisher</td>
			<td style="width:167px;">MT-16-405-CV</td>
			<td></td>
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			<td height="21" style="height:21px;width:415px;">Dulbecco&#8217;s Modified Eagle Medium (DMEM)</td>
			<td style="width:139px;">ThermoFisher</td>
			<td style="width:167px;">11-965-118</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">Dulbecco&#8217;s Phosphate-Buffered Saline (DPBS)</td>
			<td style="width:139px;">ThermoFisher</td>
			<td style="width:167px;">14190-144</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">Epidermal Growth Factor (EGF)</td>
			<td style="width:139px;">Sigma</td>
			<td style="width:167px;">E9644-.2MG</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">Ethylenediaminetetraacetic acid (EDTA)</td>
			<td style="width:139px;">Sigma</td>
			<td style="width:167px;">EDS-500G</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">Fetal Bovine Serum (FBS)</td>
			<td style="width:139px;">Gemini Bio-Pro</td>
			<td style="width:167px;">100-125</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">Gentamicin</td>
			<td style="width:139px;">Sigma</td>
			<td style="width:167px;">G5013-1G</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">GlutaMAX (L-glutamine)</td>
			<td style="width:139px;">ThermoFisher</td>
			<td style="width:167px;">35050-061</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">Insulin</td>
			<td style="width:139px;">Sigma</td>
			<td style="width:167px;">I9278-5mL</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">[leu] 15-gastrin 1</td>
			<td style="width:139px;">Sigma</td>
			<td style="width:167px;">G9145-.1MG</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">Lipopolysaccharide (LPS)</td>
			<td style="width:139px;">Sigma</td>
			<td style="width:167px;">L2630-25MG</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">N-2 supplement</td>
			<td style="width:139px;">ThermoFisher</td>
			<td style="width:167px;">17502-048</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">N-2-hydroxyethylpiperazine-N-2-ethane sulfonic acid (HEPES)</td>
			<td style="width:139px;">ThermoFisher</td>
			<td style="width:167px;">15630-080</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">N-Acetylcysteine</td>
			<td style="width:139px;">Sigma</td>
			<td style="width:167px;">A9165-5G</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">Nicotinamide</td>
			<td style="width:139px;">Sigma</td>
			<td style="width:167px;">N0636-100G</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">Noggin</td>
			<td style="width:139px;">R&#38;D Systems INC</td>
			<td style="width:167px;">6057-NG/CF</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">Penicillin-Streptomycin</td>
			<td style="width:139px;">ThermoFisher</td>
			<td style="width:167px;">15140-148</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">Phosphate Buffered Saline (PBS)</td>
			<td>Sigma</td>
			<td>P5368-5X10PAK</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">RPMI 1640 Medium</td>
			<td style="width:139px;">Invitrogen</td>
			<td>11875093</td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:415px;">R-Spondin</td>
			<td style="width:139px;">PEPROTECH INC</td>
			<td style="width:167px;">120-38</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">SB202190</td>
			<td style="width:139px;">Sigma</td>
			<td style="width:167px;">S7067-5MG</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Tissue Processing Gel (Histogel)</td>
			<td style="width:139px;">ThermoFisher</td>
			<td>22-110-678</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">Wnt3a</td>
			<td style="width:139px;">R&#38;D Systems INC</td>
			<td style="width:167px;">5036-WN-010</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">Y-27632</td>
			<td style="width:139px;">Sigma</td>
			<td style="width:167px;">Y0503-1MG</td>
			<td></td>
		</tr>
	</tbody>
</table>

a novel human epithelial enteroid model of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a devastating disease of newborn infants. It is characterized by multiple pathophysiologic alterations in the human intestinal epithelium, leading to increased intestinal permeability, impaired restitution, and increased cell death. Although there are numerous animal models of NEC, response to injury and therapeutic interventions may be highly variable between species. Furthermore, it is ethically challenging to study disease pathophysiology or novel therapeutic agents directly in human subjects, especially children. Therefore, it is highly desirable to develop a novel model of NEC using human tissue. Enteroids are 3-dimensional organoids derived from intestinal epithelial cells. They are ideal for the study of complex physiologic interactions, cell signaling, and host-pathogen defense. In this manuscript we describe a protocol that cultures human enteroids after isolating intestinal stem cells from patients undergoing bowel resection. The crypt cells are cultured in media containing growth factors that encourage differentiation into the various cell types native of the human intestinal epithelium. These cells are grown in a synthetic, collagenous mix of proteins that serve as a scaffold, mimicking the extra-cellular basement membrane. As a result, enteroids develop apical-basolateral polarity. Co-administration of lipopolysaccharide (LPS) in media causes an inflammatory response in the enteroids, leading to histologic, genetic, and protein expression alterations similar to those seen in human NEC. An experimental model of NEC using human tissue may provide a more accurate platform for drug and treatment testing prior to human trials, as we strive to identify a cure for this disease.

Immediately after plating, the freshly isolated intestinal crypts appear as elongated rods. Within hours, the enteroid will take on a round appearance (Figure 1a). Over the next several days, the enteroids will start forming spheres as seen in Figure 1b. Budding should occur between 5-10 days (Figure 1c) and enteroid collection should occur at that t...

Watch this Scientific Journal Video about A Novel Human Epithelial Enteroid Model of Necrotizing Enterocolitis at JoVE.com

A Novel Human Epithelial Enteroid Model of Necrotizing Enterocolitis

Enteroids are emerging as a novel model in the study of human disease. The protocol describes how to simulate an enteroid model of human necrotizing enterocolitis using lipopolysaccharide (LPS) treatment of enteroids generated from neonatal tissue. Collected enteroids demonstrate inflammatory changes akin to those seen in human necrotizing enterocolitis.

Necrotizing enterocolitis (NEC) is a devastating disease of newborn infants. It is characterized by multiple pathophysiologic alterations in the human ...

Enteroids are three dimensional organoids derived from intestinal epithelial cells. They are ideal for the study of complex physiological interactions, cell signaling, and host pathogen defense. Our protocol describes how to culture human enteroids after isolating intestinal stem cells from patients undergoing bowel resection.Co-administration of lipopolysaccharide in our culture media causes an inflammatory response in the enteroids leading to histologic, genetic, and protein expression alterations similar to those seen in human necrotizing enterocolitis. Given that the study of necrotizing enterocolitis and potential therapeutic agents is ethically challenging in human subjects, especially children, it is highly desirable to utilize this novel, biologically relevant enteroid model of necrotizing enterocolitis using human neonatal tissue. The main advantage of this technique is that enteroids are able to recapitulate the multiple cells types of human intestinal epithelium and are able to overcome the recognized limitations of animal models and cell based systems.Helping to demonstrate the procedure will be Christie Buonpane, a surgical resident, and Carrie Yuan, a laboratory technician from our laboratory. At the time of collection in the operative suite, place the human small intestinal tissue sample in cold DPBS. Wash the specimen in the cold DPBS until it is clear of blood and stool.Store the specimen in RPMI 1640 medium at four degrees Celsius until ready for crypt isolation. When ready to proceed, check again that the specimen is clear of stool and blood. Using delicate dissecting scissors remove any excess fat or surgical clips and staples.Weight the specimen and aim for a piece that is approximately 0.75 to 2.5 grams. Next, cut the tissue into 0.5 centimeter pieces and place them in a tube containing 30 milliliters of chelating buffer number one. Shake at a low speed for 15 minutes at four degrees Celsius.Then, filter the tissue through a 100 micrometer cell strainer and discard the flow through. Add the filtered tissue to a tube containing 30 milliliters of chelating buffer number two. Shake at a low speed for 15 minutes at four degrees Celsius.Filter the tissue through a 100 micrometer filter and discard the flow through. After this, thaw 500 microliters of basement membrane matrix on ice for later use. Add some tissue to 10 milliliters of cold DMEM in a 50 milliliter conical tube and shake vigorously by hand for 10 seconds.Filter this suspension through a 100 micrometer cell strainer and collect the flow through. Keep this tube on ice. Add some tissue to another 10 milliliters of cold DMEM in a separate 50 milliliter conical tube and shake vigorously by hand for 10 seconds.Filter this suspension through a 100 micrometer cell strainer and collect the flow through. Repeat the process two additional times until there are four conical tubes containing flow through labeled one through four. Then, filter the solution in tube number one through a 100 micrometer cell strainer and transfer the flow through into a 15 milliliter conical tube also labeled number one.Repeat this process for tubes two through four. Centrifuge the 15 milliliter tubes at 200 times G and at four degrees Celsius for 15 minutes. In the laminar flow hood, remove the supernatant from each tube and discard it.Avoid disrupting the cloud of tissue immediately above the pellet, even if that means leaving some supernatant behind. In each tube, pipette up and down slowly to mix the pellet with the leftover supernatant. Transfer the mixture from each tube into a single two milliliter conical tube and centrifuge at 200 times G and at four degrees Celsius for 20 minutes.After this, remove the supernatant and resuspend the pellet in 500 microliters of pre-thawed basement membrane matrix. Use a chilled pipette tip to apply 50 microliters of this suspension to the center of a well in a 24 well plate. This sample should appear dome shaped.Repeat this application process nine times to fill 10 total wells. Transfer the 24 well plate into a 5%carbon dioxide incubator at 37 degrees Celsius for 30 minutes to allow polymerization. Then, add 500 microliters of human minigut media complete to each well.Continue incubating under the same conditions, making sure to replace this media every two days. First, add 10 microliters of LPS at a concentration of five milligrams per milliliter to the 500 microliters of human minigut media complete in each well of the plate on day zero. Continue incubating at 37 degrees Celsius with 5%carbon dioxide and replace the supplemented media every two days until collection.To prepare for paraffin embedding, first gently remove the media, add one milliliter of PBS, and gently pipette up and down to dissolve the basement membrane matrix while being careful not to lyse the enteroids. Centrifuge at a speed less than 300 times G for five minutes to pellet and then remove the PBS. Add 4%paraformaldehyde and set the tube aside for one hour to fix at room temperature.Centrifuge at a speed less than 300 times G for five minutes to pellet and then remove the paraformaldehyde. Wash gently with one milliliter of PBS and centrifuge at a speed less than 300 times G for five minutes. Then remove the PBS.Repeat this wash process with PBS once. Place the desired amount of the tissue processing gel into a conical tube and warm it in a dry bath incubator at 65 degrees Celsius for three to 10 minutes until it is liquid. After this, add the melted tissue processing gel to the pellet and mix gently.Place a small cloning ring into a coverslip. Pipette the tissue processing gel and enteroid mixture into the cloning ring that is mounted onto a coverslip. Allow the tissue processing gel and the enteroid mixture to solidify at four degrees Celsius for one hour.Then, submerge the cloning ring with the solidified mixture into 70%ethanol to prepare for paraffin embedding. Immediately after plating, the freshly isolating intestinal crypts appear as elongated rods. Within hours the enteroids will take on a round appearance.Over the next several days the enteroids will start forming spheres. Budding should occur between five to 10 days, which is when enteroid collection should occur. The growing enteroids also exhibit polarity, containing a centralized lumen, an apical border, and a basilateral domain.Enteroids also show structural integrity represented by a robust actin cytoskeleton. After several days in culture, the LBS treated enteroids experience more apoptosis and have a lower yield than the control group. As seen in human NEC in murine models of NEC, an increased expression of toll like receptor four is found in LPS treated enteroids compared to controls.The enteroids can also be collected for RNA and protein extraction using well established qRT-PCR and western blotting techniques gene expression and protein isolation can be performed.

a-novel-human-epithelial-enteroid-model-of-necrotizing-enterocolitis

Research

JoVE Journal

Immunology and Infection

Application of a Mouse Ligated Peyer&#x2019;s Patch Intestinal Loop Assay to Evaluate Bacterial Uptake by M cells

The inside of our gut is inhabited with enormous number of commensal bacteria. The mucosal surface of the gastrointestinal tract is continuously exposed to them and occasionally to pathogens. The gut-associated lymphoid tissue (GALT) play a key role for induction of the mucosal immune response to these microbes1, 2. To initiate the mucosal immune response, the mucosal antigens must be transported from the gut lumen across the epithelial barrier into organized lymphoid follicles such as Peyer's patches. This antigen transcytosis is mediated by specialized epithelial M cells3, 4. M cells are atypical epithelial cells that actively phagocytose macromolecules and microbes. Unlike dendritic cells (DCs) and macrophages, which target antigens to lysosomes for degradation, M cells mainly transcytose the internalized antigens. This vigorous macromolecular transcytosis through M cells delivers antigen to the underlying organized lymphoid follicles and is believed to be essential for initiating antigen-specific mucosal immune responses. However, the molecular mechanisms promoting this antigen uptake by M cells are largely unknown. We have previously reported that glycoprotein 2 (Gp2), specifically expressed on the apical plasma membrane of M cells among enterocytes, serves as a transcytotic receptor for a subset of commensal and pathogenic enterobacteria, including Escherichia coli and Salmonella enterica serovar Typhimurium (S. Typhimurium), by recognizing FimH, a component of type I pili on the bacterial outer membrane 5. Here, we present a method for the application of a mouse Peyer's patch intestinal loop assay to evaluate bacterial uptake by M cells. This method is an improved version of the mouse intestinal loop assay previously described 6, 7. The improved points are as follows: 1. Isoflurane was used as an anesthetic agent. 2. Approximately 1 cm ligated intestinal loop including Peyer's patch was set up. 3. Bacteria taken up by M cells were fluorescently labeled by fluorescence labeling reagent or by overexpressing fluorescent protein such as green fluorescent protein (GFP). 4. M cells in the follicle-associated epithelium covering Peyer's patch were detected by whole-mount immunostainig with anti Gp2 antibody. 5. Fluorescent bacterial transcytosis by M cells were observed by confocal microscopic analysis. The mouse Peyer's patch intestinal loop assay could supply the answer what kind of commensal or pathogenic bacteria transcytosed by M cells, and may lead us to understand the molecular mechanism of how to stimulate mucosal immune system through M cells.

Application of a Mouse Ligated Peyer&#8217;s Patch Intestinal Loop Assay to Evaluate Bacterial Uptake by M cells

M cells in a specialized follicle-associated epithelium covering Peyer&#x2019;s patches play an important role for the mucosal immunosurveillance in gut-associated lymphoid tissue. Here we described the evaluation method for bacterial transcytosis by M cells in vivo. This method provides a method to understand M-cell function in the immune system.

The inside of our gut is inhabited with enormous number of commensal bacteria. The mucosal surface of the gastrointestinal tract is continuously exposed ...

An In vitro Model to Study Heterogeneity of Human Macrophage Differentiation and Polarization

Monocyte-derived macrophages represent an important cell type of the innate immune system. Mouse models studying macrophage biology suffer from the phenotypic and functional differences between murine and human monocyte-derived macrophages. Therefore, we here describe an in vitro model to generate and study primary human macrophages. Briefly, after density gradient centrifugation of peripheral blood drawn from a forearm vein, monocytes are isolated from peripheral blood mononuclear cells using negative magnetic bead isolation. These monocytes are then cultured for six days under specific conditions to induce different types of macrophage differentiation or polarization. The model is easy to use and circumvents the problems caused by species-specific differences between mouse and man. Furthermore, it is closer to the in vivo conditions than the use of immortalized cell lines. In conclusion, the model described here is suitable to study macrophage biology, identify disease mechanisms and novel therapeutic targets. Even though not fully replacing experiments with animals or human tissues obtained post mortem, the model described here allows identification and validation of disease mechanisms and therapeutic targets that may be highly relevant to various human diseases.

An In vitro Model to Study Heterogeneity of Human Macrophage Differentiation and Polarization

Monocyte-derived macrophages are important cells of the innate immune system. Here, we describe an easy to use in vitro model to generate these cells. Using gradient centrifugation, negative bead isolation and specific cell culture conditions, monocyte-derived macrophages can be generated for phenotypic and functional studies.

Monocyte-derived macrophages represent an important cell type of the innate immune system. Mouse models studying macrophage biology suffer from the ...

An In vitro Model to Study Immune Responses of Human Peripheral Blood Mononuclear Cells to Human Respiratory Syncytial Virus Infection

Human respiratory syncytial virus (HRSV) infections present a broad spectrum of disease severity, ranging from mild infections to life-threatening bronchiolitis. An important part of the pathogenesis of severe disease is an enhanced immune response leading to immunopathology.	Here, we describe a protocol used to investigate the immune response of human immune cells to an HRSV infection. First, we describe methods used for culturing, purification and quantification of HRSV. Subsequently, we describe a human in vitro model in which peripheral blood mononuclear cells (PBMCs) are stimulated with live HRSV. This model system can be used to study multiple parameters that may contribute to disease severity, including the innate and adaptive immune response. These responses can be measured at the transcriptional and translational level. Moreover, viral infection of cells can easily be measured using flow cytometry. Taken together, stimulation of PBMC with live HRSV provides a fast and reproducible model system to examine mechanisms involved in HRSV-induced disease.

An In vitro Model to Study Immune Responses of Human Peripheral Blood Mononuclear Cells to Human Respiratory Syncytial Virus Infection

Human respiratory syncytial virus (HRSV) can cause severe bronchiolitis in young infants. Part of the pathogenesis of severe HRSV disease is caused by the host immune response. Stimulation of primary human immune cells with HRSV provides a fast and reproducible model system to study activation of inflammatory pathways and infection.

Human respiratory syncytial  virus (HRSV) infections present a broad spectrum of disease severity, ranging  from mild infections to life-threatening ...

Isolation of Myeloid Dendritic Cells and Epithelial Cells from Human Thymus

In this protocol we provide a method to isolate dendritic cells (DC) and epithelial cells (TEC) from the human thymus. DC and TEC are the major antigen presenting cell (APC) types found in a normal thymus and it is well established that they play distinct roles during thymic selection. These cells are localized in distinct microenvironments in the thymus and each APC type makes up only a minor population of cells. To further understand the biology of these cell types, characterization of these cell populations is highly desirable but due to their low frequency, isolation of any of these cell types requires an efficient and reproducible procedure. This protocol details a method to obtain cells suitable for characterization of diverse cellular properties. Thymic tissue is mechanically disrupted and after different steps of enzymatic digestion, the resulting cell suspension is enriched using a Percoll density centrifugation step. For isolation of myeloid DC (CD11c+), cells from the low-density fraction (LDF) are immunoselected by magnetic cell sorting. Enrichment of TEC populations (mTEC, cTEC) is achieved by depletion of hematopoietic (CD45hi) cells from the low-density Percoll cell fraction allowing their subsequent isolation via fluorescence activated cell sorting (FACS) using specific cell markers. The isolated cells can be used for different downstream applications.

This protocol details a method to isolate antigen presenting cells from human thymus via different steps of enzymatic digestion of the tissue followed by density centrifugation of the single cell suspension and finally magnetic and/or FACS sorting of the cell populations of interest.

In this protocol we provide a method to isolate dendritic cells (DC) and epithelial cells (TEC) from the human thymus. DC and TEC are the major antigen ...

Isolation, Identification, and Purification of Murine Thymic Epithelial Cells

The thymus is a vital organ for T lymphocyte development. Of thymic stromal cells, thymic epithelial cells (TECs) are particularly crucial at multiple stages of T cell development: T cell commitment, positive selection and negative selection. However, the function of TECs in the thymus remains incompletely understood. In the article, we provide a method to isolate TEC subsets from fresh mouse thymus using a combination of mechanical disruption and enzymatic digestion. The method allows thymic stromal cells and thymocytes to be efficiently released from cell-cell and cell-extracellular matrix connections and to form a single-cell suspension. Using the isolated cells, multiparameter flow cytometry can be applied to identification and characterization of TECs and dendritic cells. Because TECs are a rare cell population in the thymus, we also describe an effective way to enrich and purify TECs by depleting thymocytes, the most abundant cell type in the thymus. Following the enrichment, cell sorting time can be decreased so that loss of cell viability can be minimized during purification of TECs. Purified cells are suitable for various downstream analyses like Real Time-PCR, Western blot and gene expression profiling. The protocol will promote research of TEC function and as well as the development of in vitro T cell reconstitution.

Here we describe an efficient method for isolation, identification, and purification of mouse thymic epithelial cells (TECs). The protocol can be utilized for studies of thymus function for normal T cell development, thymus dysfunction, and T cell reconstitution.

The thymus is a vital organ for T lymphocyte development. Of thymic stromal cells, thymic epithelial cells (TECs) are particularly crucial at multiple ...

A Novel In vitro Model for Studying the Interactions Between Human Whole Blood and Endothelium

The majority of all known diseases are accompanied by disorders of the cardiovascular system. Studies into the complexity of the interacting pathways activated during cardiovascular pathologies are, however, limited by the lack of robust and physiologically relevant methods. In order to model pathological vascular events we have developed an in vitro assay for studying the interaction between endothelium and whole blood. The assay consists of primary human endothelial cells, which are placed in contact with human whole blood. The method utilizes native blood with no or very little anticoagulant, enabling study of delicate interactions between molecular and cellular components present in a blood vessel.
We investigated functionality of the assay by comparing activation of coagulation by different blood volumes incubated with or without human umbilical vein endothelial cells (HUVEC). Whereas a larger blood volume contributed to an increase in the formation of thrombin antithrombin (TAT) complexes, presence of HUVEC resulted in reduced activation of coagulation. Furthermore, we applied image analysis of leukocyte attachment to HUVEC stimulated with tumor necrosis factor (TNF&#945;) and found the presence of CD16+ cells to be significantly higher on TNF&#945; stimulated cells as compared to unstimulated cells after blood contact. In conclusion, the assay may be applied to study vascular pathologies, where interactions between the endothelium and the blood compartment are perturbed.

A Novel In vitro Model for Studying the Interactions Between Human Whole Blood and Endothelium

The accessibility of reliable models to investigate vascular blood interactions in humans is lacking. We present an in vitro model of cultured primary human endothelial cells combined with human whole blood to investigate cellular interactions both in the blood (ELISA) and the vascular compartment (microscopy).

The majority of all known diseases are accompanied by disorders of the cardiovascular system. Studies into the complexity of the interacting pathways ...

Development and Identification of a Novel Subpopulation of Human Neutrophil-derived Giant Phagocytes In Vitro

Neutrophils (PMN) are best known for their phagocytic functions against invading pathogens and microorganisms. They have the shortest half-life amongst leukocytes and in their non-activated state are constitutively committed to apoptosis. When recruited to inflammatory sites to resolve inflammation, they produce an array of cytotoxic molecules with potent antimicrobial killing. Yet, when these powerful cytotoxic molecules are released in an uncontrolled manner they can damage surrounding tissues. In recent years however, neutrophil versatility is increasingly evidenced, by demonstrating plasticity and immunoregulatory functions. We have recently identified a new neutrophil-derived subpopulation, which develops spontaneously in standard culture conditions without the addition of cytokines/growth factors such as granulocyte colony-stimulating factor (GM-CSF)/interleukin (IL)-4. Their phagocytic abilities of neutrophil remnants largely contribute to increase their size immensely; therefore they were termed giant phagocytes (G&#981;). Unlike neutrophils, G&#981; are long lived in culture. They express the cluster of differentiation (CD) neutrophil markers CD66b/CD63/CD15/CD11b/myeloperoxidase (MPO)/neutrophil elastase (NE), and are devoid of the monocytic lineage markers CD14/CD16/CD163 and the dendritic CD1c/CD141 markers. They also take-up latex and zymosan, and respond by oxidative burst to stimulation with opsonized-zymosan and PMA. G&#981; also express the scavenger receptors CD68/CD36, and unlike neutrophils, internalize oxidized-low density lipoprotein (oxLDL). Moreover, unlike fresh neutrophils, or cultured monocytes, they respond to oxLDL uptake by increased reactive oxygen species (ROS) production. Additionally, these phagocytes contain microtubule-associated protein-1 light chain 3B (LC3B) coated vacuoles, indicating the activation of autophagy. Using specific inhibitors it is evident that both phagocytosis and autophagy are prerequisites for their development and likely NADPH oxidase dependent ROS. We describe here a method for the preparation of this new subpopulation of long-lived, neutrophil-derived phagocytic cells in culture, their identification and their currently known characteristics. This protocol is essential for obtaining and characterizing G&#981; in order to further investigate their significance and functions.

Development and Identification of a Novel Subpopulation of Human Neutrophil-derived Giant Phagocytes In Vitro

We describe here a method for obtaining and identifying a newly characterized subpopulation of neutrophil-derived giant phagocytes. These cells develop in culture from fresh human blood neutrophils, and are characterized by phagocytosis, autophagy, immensely large size, and extended lifespan. This method is essential to further investigate this unique neutrophil-derived subpopulation.

Neutrophils (PMN) are best known for their phagocytic functions against invading pathogens and microorganisms. They have the shortest half-life amongst ...

Using Human Induced Pluripotent Stem Cell-derived Intestinal Organoids to Study and Modify Epithelial Cell Protection Against Salmonella and Other Pathogens

The intestinal &#8216;organoid&#8217; (iHO) system, wherein 3-D structures representative of the epithelial lining of the human gut can be produced from human induced pluripotent stem cells (hiPSCs) and maintained in culture, provides an exciting opportunity to facilitate the modeling of the epithelial response to enteric infections. In vivo, intestinal epithelial cells (IECs) play a key role in regulating intestinal homeostasis and may directly inhibit pathogens, although the mechanisms by which this occurs are not fully elucidated. The cytokine interleukin-22 (IL-22) has been shown to play a role in the maintenance and defense of the gut epithelial barrier, including inducing a release of antimicrobial peptides and chemokines in response to infection.
We describe the differentiation of healthy control hiPSCs into iHOs via the addition of specific cytokine combinations to their culture medium before embedding them into a basement membrane matrix-based prointestinal culture system. Once embedded, the iHOs are grown in media supplemented with Noggin, R-spondin-1, epidermal growth factor (EGF), CHIR99021, prostaglandin E2, and Y-27632 dihydrochloride monohydrate. Weekly passages by manual disruption of the iHO ultrastructure lead to the formation of budded iHOs, with some exhibiting a crypt/villus structure. All iHOs demonstrate a differentiated epithelium consisting of goblet cells, enteroendocrine cells, Paneth cells, and polarized enterocytes, which can be confirmed via immunostaining for specific markers of each cell subset, transmission electron microscopy (TEM), and quantitative PCR (qPCR). To model infection, Salmonella enterica serovar Typhimurium SL1344 are microinjected into the lumen of the iHOs and incubated for 90 min at 37 &#176;C, and a modified gentamicin protection assay is performed to identify the levels of intracellular bacterial invasion. Some iHOs are also pretreated with recombinant human IL-22 (rhIL-22) prior to infection to establish whether this cytokine is protective against Salmonella infection.

Using Human Induced Pluripotent Stem Cell-derived Intestinal Organoids to Study and Modify Epithelial Cell Protection Against Salmonella and Other Pathogens

Human induced pluripotent stem cell (hiPSC)-derived intestinal organoids offer exciting opportunities to model enteric diseases in vitro. We demonstrate the differentiation of hiPSCs into intestinal organoids (iHOs), the stimulation of these iHOs with cytokines, and the microinjection of Salmonella Typhimurium into the iHO lumen, enabling the study of an epithelial invasion by this pathogen.

The intestinal &#8216;organoid&#8217; (iHO) system, wherein 3-D structures representative of the epithelial lining of the human gut can be produced from ...

Induced Differentiation of M Cell-like Cells in Human Stem Cell-derived Ileal Enteroid Monolayers

M (microfold) cells of the intestine function to transport antigen from the apical lumen to the underlying Peyer&#8217;s patches and lamina propria where immune cells reside and therefore contribute to mucosal immunity in the intestine. A complete understanding of how M cells differentiate in the intestine as well as the molecular mechanisms of antigen uptake by M cells is lacking. This is because M cells are a rare population of cells in the intestine and because in vitro models for M cells are not robust. The discovery of a self-renewing stem cell culture system of the intestine, termed enteroids, has provided new possibilities for culturing M cells. Enteroids are advantageous over standard cultured cell lines because they can be differentiated into several major cell types found in the intestine, including goblet cells, Paneth cells, enteroendocrine cells and enterocytes. The cytokine RANKL is essential in M cell development, and addition of RANKL and TNF-&#945; to culture media promotes a subset of cells from ileal enteroids to differentiate into M cells. The following protocol describes a method for the differentiation of M cells in a transwell epithelial polarized monolayer system of the intestine using human ileal enteroids. This method can be applied to the study of M cell development and function.

This protocol describes how to induce the differentiation of M cells in human stem cell-derived ileal monolayers and methods to assess their development.

M (microfold) cells of the intestine function to transport antigen from the apical lumen to the underlying Peyer&#8217;s patches and lamina propria where ...

A Novel High-Throughput Ex Vivo Ovine Skin Wound Model for Testing Emerging Antibiotics

The development of antimicrobials is an expensive process with increasingly low success rates, which makes further investment in antimicrobial discovery research less attractive. Antimicrobial drug discovery and subsequent commercialization can be made more lucrative if a fail-fast-and-fail-cheap approach can be implemented within the lead optimization stages where researchers have greater control over drug design and formulation. In this article, the setup of an ex vivo ovine wounded skin model infected with Staphylococcus aureus&#160;is described, which is simple, cost-effective, high throughput, and reproducible. The bacterial physiology in the model mimics that during infection as bacterial proliferation is dependent on the pathogen&#39;s ability to damage the tissue. The establishment of wound infection is verified by an increase in viable bacterial counts compared to the inoculum. This model can be used as a platform to test the efficacy of emerging antimicrobials in the lead optimization stage. It can be contended that the availability of this model will provide researchers developing antimicrobials with a fail-fast-and-fail-cheap model, which will help increase success rates in subsequent animal trials. The model will also facilitate the reduction and refinement of animal use for research and ultimately enable faster and more cost-effective translation of novel antimicrobials for skin and soft tissue infections to the clinic.

A Novel High-Throughput Ex Vivo Ovine Skin Wound Model for Testing Emerging Antibiotics

The protocol describes a step-by-step method to set up an ex vivo ovine wounded skin model infected with Staphylococcus aureus. This high-throughput model better simulates infections in vivo compared with conventional microbiology techniques and presents researchers with a physiologically relevant platform to test the efficacy of emerging antimicrobials.

The development of antimicrobials is an expensive process with increasingly low success rates, which makes further investment in antimicrobial discovery ...