Name: Author Spotlight: Investigating the Effects of Compounds on Intestinal Tissue Using 3D Human Cell Line Models
Uploaded: 2023-09-01T13:00:00
Description: Watch this Scientific Journal Video about Investigating the Effects of Compounds on Intestinal Tissue Using 3D Human Cell Line Models at JoVE.com

Thanks to the Umberto Veronesi Foundation for a fellowship supporting researcher work.

1. Preparation of the basic 3D reconstructed intestinal mucosa model
NOTE: The entire procedure must be carried out in a sterile laminar flow hood. All steps in the procedure involving the use of the cell incubator signify that cultures are incubated at 37 &#176;C in a humidified atmosphere containing 5% CO2 (unless stated otherwise in the protocol).
<ol>
	<li>Prior preparation of the cell lines used in the intestinal model system
	<ol>
		<li>Seed L929 mouse fibroblast ...

Construction of a 3D Intestinal Mucosa Model with Paraffin Embedding

<ol>
	<li>Chelakkot, C., Ghim, J., Ryu, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanisms+regulating+intestinal+barrier+integrity+and+its+pathological+implications.">Mechanisms regulating intestinal barrier integrity and its pathological implications.</a> Experimental &amp; Molecular Medicine. 50 (8), 1-9 (2018).</li><li>Schoultz, I., Keita, &. #. 1. 9. 7. ;. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+intestinal+barrier+and+current+techniques+for+the+assessment+of+gut+permeability.">The intestinal barrier and current techniques for the assessment of gut permeability.</a> Cells. 9 (8), 1909 (1909).</li><li>Bednarek, R. <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+methods+for+measuring+the+permeability+of+cell+monolayers.">In vitro methods for measuring the permeability of cell monolayers.</a> Methods and Protocols. 5 (1), 17 (2022).</li><li>Suzuki, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+the+intestinal+barrier+by+nutrients:+The+role+of+tight+junctions.">Regulation of the intestinal barrier by nutrients: The role of tight junctions.</a> Animal Science Journal. 91 (1), e13357 (2020).</li><li>Guibourdenche, M., 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=Food+contaminants+effects+on+an+in+vitro+model+of+human+intestinal+epithelium.">Food contaminants effects on an in vitro model of human intestinal epithelium.</a> Toxics. 9 (6), 135 (2021).</li><li>Panwar, S., Sharma, S., Tripathi, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+barrier+integrity+and+dysfunctions+in+maintaining+the+healthy+gut+and+their+health+outcomes.">Role of barrier integrity and dysfunctions in maintaining the healthy gut and their health outcomes.</a> Frontiers in Physiology. 12, 715611 (2021).</li><li>Truzzi, F., 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=Pro-inflammatory+effect+of+gliadins+and+glutenins+extracted+from+different+wheat+cultivars+on+an+in+vitro+3D+intestinal+epithelium+model.">Pro-inflammatory effect of gliadins and glutenins extracted from different wheat cultivars on an in vitro 3D intestinal epithelium model.</a> International Journal of Molecular Sciences. 22 (1), 172 (2020).</li><li>Fedi, 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=In+vitro+models+replicating+the+human+intestinal+epithelium+for+absorption+and+metabolism+studies:+A+systematic+review.">In vitro models replicating the human intestinal epithelium for absorption and metabolism studies: A systematic review.</a> Journal of Controlled Release. 335, 247-268 (2021).</li><li>De Fazio, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Necrotizing+enterocolitis:+Overview+on+in+vitro+models.">Necrotizing enterocolitis: Overview on in vitro models.</a> International Journal of Molecular Sciences. 22 (13), 6761 (2021).</li><li>Jubelin, C., 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=Three-dimensional+in+vitro+culture+models+in+oncology+research.">Three-dimensional in vitro culture models in oncology research.</a> Cell &amp; Bioscience. 12 (1), 155 (2022).</li><li>Russell, W., Burch, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+principles+of+humane+experimental+technique.">The principles of humane experimental technique.</a> Available online. , (2023).</li><li>Ingber, D. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Is+it+time+for+reviewer+3+to+request+human+organ+chip+experiments+instead+of+animal+validation+studies.">Is it time for reviewer 3 to request human organ chip experiments instead of animal validation studies.</a> Advanced Science. 7 (22), 2002030 (2020).</li><li>Jung, S. M., Kim, S. <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+models+of+the+small+intestine+for+studying+intestinal+diseases.">In vitro models of the small intestine for studying intestinal diseases.</a> Frontiers in Microbiology. 12, 767038 (2022).</li><li>Nitsche, K. S., M&#252;ller, I., Malcomber, S., Carmichael, P. L., Bouwmeester, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Implementing+organ-on-chip+in+a+next-generation+risk+assessment+of+chemicals:+a+review.">Implementing organ-on-chip in a next-generation risk assessment of chemicals: a review.</a> Archives of Toxicology. 96 (3), 711-741 (2022).</li><li>Kekilli, M., 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=Midkine+level+may+be+used+as+a+noninvasive+biomarker+in+Crohn's+disease.">Midkine level may be used as a noninvasive biomarker in Crohn's disease.</a> Turkish Journal of Medical Sciences. 50, 324-329 (2020).</li><li>Truzzi, F., 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=Spermidine-eugenol+supplement+preserved+inflammation-challenged+intestinal+cells+by+stimulating+autophagy.">Spermidine-eugenol supplement preserved inflammation-challenged intestinal cells by stimulating autophagy.</a> International Journal of Molecular Sciences. 24 (4), 4131 (2023).</li><li>Truzzi, F., 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=Are+supplements+safe?+Effects+of+gallic+and+ferulic+acids+on+in+vitro+cell+models.">Are supplements safe? Effects of gallic and ferulic acids on in vitro cell models.</a> Nutrients. 12 (6), 1591 (2020).</li><li>Buckley, A. 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=Visualisation+of+multiple+tight+junctional+complexes+in+human+airway+epithelial+cells.">Visualisation of multiple tight junctional complexes in human airway epithelial cells.</a> Biological Procedures. Online. 20, 3 (2018).</li><li>Ghosh, R., Gilda, J. E., Gomes, A. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+necessity+of+and+strategies+for+improving+confidence+in+the+accuracy+of+western+blots.">The necessity of and strategies for improving confidence in the accuracy of western blots.</a> Expert Review of Proteomics. 11 (5), 549-560 (2014).</li></ol>

The basic reconstructed intestinal mucosa model system presented here (Figure 6) combines physiological complexity (more physiologically relevant 3D cell cultures containing a Caco-2 monolayer with an ECM-rich lamina propria support containing fibroblasts and monocytes) with experimental simplicity (using commercial human cell lines to produce standardized and easily repeatable system)13. As such, this model system is deemed a suitable alternative to murine models aim...

The intestinal epithelial barrier, a one-cell-thick internal lining containing different types of epithelial cells, constitutes the first physical defensive barrier or interface between the outside and the internal milieu of the body1,2. Columnar-type enterocytes constitute the most abundant type of epithelial cells. These are&#160;responsible for maintaining epithelial barrier integrity through interactions between several barrier components, including tight junctions (TJs), playing a significant role in barrier tightening1,3. The TJ structure consists of intracellular plaque proteins, such as zonula occludens (ZO) and cingulin, cooperating with transmembrane proteins, including occludins, claudins, and junctional adhesion molecules (JAMs) that form zipper-like structure tightly linking the neighboring cells3,4. The transmembrane proteins regulate the passive paracellular diffusion of small compounds and exclude toxic large molecules.
Potentially toxic food compounds and food contaminants stimulate inflammatory cytokine production that disrupts the epithelial permeability, activating immune cells and causing chronic intestinal tissue inflammation5,6,7. In contrast, various anti-oxidant and anti-inflammatory phytochemicals have been reported to reduce inflammatory cytokine expression and enhance intestinal TJ barrier integrity through the restoration of TJ protein expression and assembly4,6,8. Hence, the regulation of epithelial barrier integrity by both beneficial and harmful compounds has seen an increase in the use of both in vivo and in vitro models aimed at mimicking the intestinal barrier for pharmaceutical screening and toxicity studies. This is particularly relevant given the increasing interest in understanding the pathophysiology of intestinal bowel diseases (IBD), necrotizing enterocolitis, and cancer, which can be simulated in experimental models8,9,10.
There has been a demand for the development of cell-based in vitro models in order to achieve the objective of the &#8220;3Rs&#8221; in animal testing. These include replacement alternatives to the use of animals, reduction in the number of animals used, and refinement in adopting methods that alleviate distress11,12,13. Moreover, the underlying molecular, cellular, and physiological mechanisms between human and murine models (rodents being the most widely used species) are distinctive, leading to controversy regarding the efficacy of the murine models as predictors in human responses12,13. Numerous advantages of in vitro human cell-line models include target-restricted experimentation, direct observation, and continuous analysis13.
Single-cell-type monolayers in two-dimensional (2D) cultures have served as powerful models. However, these cannot precisely reproduce the physiological complexity of human tissues8,13,14. As a result, 3D&#160;culture systems are being developed with ever-increasing improvements to recapitulate the physiological complexity of both healthy and diseased intestinal tissues as next-generation risk assessment toolboxes13,14. These models include 3D Transwell scaffolds with diverse cell lines, organoid cultures, and microfluidic devices (intestine-on-chip) using both cell lines and organoids (derived from both healthy and diseased tissues)8,13,14.&#160;
The 3D &#8220;healthy tissue&#8221; intestinal equivalent protocol presented in the present study was based on striking a balance between physiological complexity and experimental simplicity13. The model is representative of a 3D Transwell scaffold, comprised of three cell lines (enterocytes [the gold-standard colon adenocarcinoma Caco-2 line] with a supporting immune component [U937 monocytes and L929 fibroblasts]), constituting a standardized and easily repeatable system applicable for the preliminary screening of dietary molecules of interest on intestinal epithelial barrier integrity and immune response. The protocol includes paraffin embedding for light microscopic evaluation of epithelial barrier integrity using fixed intestinal equivalents. The advantage of the present approach is that numerous sections of the embedded tissues can be made to stain for multiple parameters from a single experiment.

basic three-dimensional (3d) intestinal model system with an immune component

There has been an increase in the use of in vivo and in vitro intestinal models to study the pathophysiology of inflammatory intestinal diseases, for the pharmacological screening of potentially beneficial substances, and for toxicity studies on potentially harmful food components. Of relevance, there is a current demand for the development of cell-based in vitro models to substitute animal models. Here, a protocol for a basic, &#8220;healthy tissue&#8221; three-dimensional (3D) intestinal equivalent model using cell lines is presented with the dual benefit of providing both experimental simplicity (standardized and easily repeatable system) and physiological complexity (Caco-2 enterocytes with a supporting immune component of U937 monocytes and L929 fibroblasts). The protocol also includes paraffin embedding for light microscopic evaluation of fixed intestinal equivalents, thereby providing the advantage of analyzing multiple visual parameters from a single experiment. Hematoxylin and eosin (H&#38;E) stained sections showing the Caco-2 columnar cells forming a tight and regular monolayer in control treatments are used to verify the efficacy of the model as an experimental system. Using gluten as a pro-inflammatory food component, parameters analyzed from sections include reduced monolayer thickness, as well as disruption and detachment from the underlying matrix (H&#38;E), decreased tight junction protein expression as shown from occludin staining (quantifiable statistically), and immune-activation of migrating U937 cells as evidenced from the cluster of differentiation 14 (CD14) staining and CD11b-related differentiation into macrophages. As shown by using lipopolysaccharide to simulate intestinal inflammation, additional parameters that can be measured are increased mucus staining and cytokine expression (such as midkine) that can be extracted from the medium prior to fixation. The basic three-dimensional (3D) intestinal mucosa model and fixed sections can be recommended for inflammatory status and barrier integrity studies with the possibility of analyzing multiple visual quantifiable parameters.

Author Spotlight: Investigating the Effects of Compounds on Intestinal Tissue Using 3D Human Cell Line Models 

Basic Three-Dimensional (3D) Intestinal Model System with an Immune Component

The scope of the work is to use these in vitro three-dimensional human cell line models to investigate the fact of beneficial as well as helpful compounds on intestinal tissue. The models can be used to further research understanding and also as a basic drug model. Using the plant-derived compounds, spermidine and eugenol, both separately and together in supplement form, we measure beneficial increases in autophagy and decreases in inflammation using these models.Then we will also able to show the potentially harmful effect of gluten extracted from certain wheat varieties on intestinal tissues. We are currently using economically priced, standardized, and easily repeatable in vitro system that better reflect the physiology of the human intestine as an alternative to animal models. Since we also use commercial human cell line rather than plant-derived cells, the responses from the study are more applicable to the general population.The protocol is based entirely on the use of different lines. These renders the model most standardized and reproducible. Furthermore, the simultaneous cultivation of different cell lines, enterocytes, fibroblasts, and immune system cells, allows for cellular responses that are closer to what happens in the patient.

The first important aspect is to determine the acceptability of the basic 3D intestinal equivalent mucosa for experimental purposes. This is performed with the most widely used stain in histology and histopathology laboratories, namely hematoxylin (stains nuclear material deep blue-purple color) and eosin (stains cytoplasmic material varying shades of pink). The H&#38;E staining is first performed on an untreated control, which is cultured under the same conditions and timeframe as the experimental treatments. From visua...

Watch this Scientific Journal Video about Investigating the Effects of Compounds on Intestinal Tissue Using 3D Human Cell Line Models at JoVE.com

Here we describe constructing a basic three-dimensional (3D) intestinal cell line model system and a paraffin embedding protocol for light microscopic evaluation of fixed intestinal equivalents. Staining of selected proteins permits the analysis of multiple visual parameters from a single experiment for potential use in preclinical drug screening studies.

There has been an increase in the use of in vivo and in vitro intestinal models to study the pathophysiology of inflammatory intestinal diseases, for the ...