Exploring preclinical models of inflammatory bowel disease

IInflammatory bowel diseases (IBD), such as ulcerative colitis and Crohn’s disease, are syndromes caused by genetic and environmental factors that disrupt the intestinal environment. intestinal immune response.¹ Scientists continue to search for more effective and less harmful IBD treatments, but they remain elusive, in part because current model systems fail to reproduce key mechanisms of IBD. epithelial A monolayer of cells that lines the surface of the intestine.¹ To address this research gap, researchers are turning to identifying and investigating new clinically relevant preclinical IBD models. therapeutic target and biomarkers.¹

Model of inflammatory bowel disease

In vivo, the intestinal epithelium interacts with the neighboring environment through a complex crosstalk involving components such as the immune system, tissue microenvironment, and gut bacteria. Preclinical models are simplified tools that help researchers study these complex interactions in a controlled manner and prioritize relevant biochemical pathways when developing IBD treatments. .These models include: humanized A stem cell-derived in vitro system that recapitulates the composition and morphology of epithelial cell layers.²

Towards this end, scientists are increasingly employed. single layer system. These cell culture systems consist of a monolayer of stem cells, which researchers grow on a scaffold such as a membrane or hydrogel. Cells attach to the scaffold, proliferate, and differentiate into specialized intestinal cell types that recapitulate the composition of the human intestinal epithelium.²

different scaffold This will allow researchers to fine-tune the monolayer system and investigate the unique properties of the human intestinal tract. Monolayer systems cultured on porous membranes replicate both the luminal and basal sides of epithelial cell monolayers. Unlike 3D model systems, the monolayer also includes a fluid reservoir adjacent to the epithelium that allows researchers to examine external immune cues present in the gut, such as microbes and bioactive compounds. Scientists can rely on single-layer models for their simplicity, scalability, and compatibility with multiple assay readouts.²

Single layer system readout

cytotoxicity

Toxicity is an important consideration when developing new therapeutics, and the intestinal epithelium is a critical interface for therapeutics. Absorption and metabolism of drugs in vivo. For this reason, researchers embarking on drug discovery for IBD must ensure that therapeutic candidates do not damage the already fragile intestinal epithelium. Monolayer systems provide an opportunity to monitor drug toxicity in vitro, allowing researchers to quickly quantify compound safety and triage unsuitable candidates in the early stages of drug discovery.²

barrier integrity

A healthy intestinal barrier is essential to protect yourself from harmful substances leak between the intestinal lumen and adjacent tissues.³ Scientists are studying barrier breakdown as an initiating event in IBD.The main barrier cells of the small intestine and colon are epithelial cells, and dysfunction of these cells high interest rate For researchers studying barrier destruction.¹ Because the monolayers embody the characteristic luminal/basal morphology of the in vivo intestinal epithelium, researchers can use these systems to decipher how the intestine monitors its microenvironment. Masu. barrier defect and communicate with the immune system.³ Monolayer models typically form dense layers that support physiological assays of barrier function such as ion transport and barrier integrity such as transepithelial electrical resistance.Tia).²

Production of inflammatory cytokines

Researchers use these systems to barrier-mediated immune response.² In vivo, the intestine plays a central role in the maturation and function of the immune system. Barrier epithelial cells are first responders For IBD inflammation. In response to active immune cells producing interferon gamma (IFN-γ) and tumor necrosis factor (TNF-α), epithelial cells secrete immune factors such as inflammatory factors. Cytokine such as interleukin 8 (IL-8).^{2, 3} Because they imitate nature, barrier form Epithelial monolayer systems with relevant cell types and scaffolds support physiological immunoassays, including those that measure synthesis and secretion of chemokine-inflammatory cytokines.²

Monolayer model for inflammation-focused drug discovery

Monolayer models hold great promise as physiological systems for drug discovery, providing information about barrier integrity and allowing scientists to reproduce complex gut-immune interactions.of InflammaScreen™ Service Altis Biosystems’ suite of readout assays is a suite of readout assays specifically designed to accelerate drug screening and improve the human suitability of drug discovery focused on gastrointestinal inflammation.^Four This series of assays uses the Altis Biosystem RepliGut.^® The planar transverse colon model system allows researchers to rapidly test compounds, compare candidates, and triage ineffective molecules in an inflammatory epithelial monolayer system. Monitor tissue barrier integrity using TEER and assess quantitative cytotoxicity and IL-8 release. Researchers can utilize these assays to rapidly gain clinically relevant insights into intestinal inflammation.

References

1. Pizarro TT et al. Challenges in IBD research: human preclinical IBD mechanisms. inflammatory bowel disease. 2019;25(Supplement 2):S5-S12.
2. Dutton JS et al. Primary cell-derived intestinal models: recapitulating physiology. trend biotechnology. 2019;37(7):744-60.
3. Wang Y et al. Analysis of interleukin-8 secretion using a stem cell-derived human intestinal epithelial monolayer platform. anal chem. 2018;90(19):11523-30.
4. InflammaScreen™ Service. Altis Biosystems. Accessed September 15, 2023.