assessing epithelial barrier integrity of organoid-derived 2d monolayers using paracellular permeability assay

Developing 2D Monolayer Cultures from Bovine Intestinal Organoids

The culture of intestinal epithelial stem cells in three-dimensional (3D) cultures, known as intestinal organoids, marks a significant advancement in in vitro technology for investigating intestinal functions, nutrition, and interactions with pathogens1,2. These organoids mimic the complex structure of the in vivo intestinal epithelium by self-replicating and organizing into 3D formations that encompass various intestinal cell lineages3. This feature highlights their considerable potential to propel the understanding of intestinal biology forward.
The rising interest in applying intestinal organoid technology to farm animals necessitates the refinement of culture and maintenance techniques4,5. This technology&#39;s relevance is underscored by its potential impact on studying the gut health of farm animals, which plays a critical role in their productivity and, consequently, the economics of the food-animal industry by influencing animal welfare and operational costs6,7. Specifically, employing intestinal organoid cultures to explore the gut function of cattle is of paramount importance, given their role as reservoirs for zoonotic enteric pathogens, such as Salmonella spp. and Escherichia coli (E. coli) O157:H78. These pathogens are localized in particular segments of the gut, making it essential to differentiate intestinal organoid culture methods by gut segment to enhance precision in studies9.
A significant obstacle in the study of intestinal organoids is the restricted access to the epithelial cell&#39;s apical surface10. When cultured within an extracellular matrix (ECM), the cells naturally orient themselves so the basal surface faces outward, and the apical surface is directed inward10. To address this challenge, methods are presented that involve dissociating 3D organoids into single cells and seeding them into semi-permeable cell culture inserts. This setup establishes an interface between the apical surface and a basolateral compartment. This protocol demonstrates that cells derived from bovine intestinal organoids can form a coherent 2D monolayer, as evidenced by transepithelial electrical resistance (TEER) measurements and paracellular permeability assays. Additionally, the development of cellular polarity with brush borders and tight junctions in the organoid-derived 2D monolayer cells is confirmed through immunofluorescence and electron microscopy, reflecting the in vivo gut epithelium&#39;s properties.
In this study, the ileum represents the small intestinal tract, and the rectum signifies the large intestinal tract. These selections are based on relevant enteric pathogens such as Salmonella spp., which can translocate the ileum11, and E. coli O157:H7 known to primarily colonize the rectum9 in cattle. The selection of these specific intestinal segments highlights the necessity of tailoring intestinal organoid culture methods to the gut region for precision in research. These methods detail the procedure for effectively culturing an organoid-derived 2D monolayer interface from these intestinal segments, providing a robust model for exploring cattle gut health, pathogen infections, and interactions between the gut microbiome and host.

Author Spotlight: Development and Characterization of 2D Intestinal Monolayer Models from Bovine Organoids for Pathogen Interaction Studies

Advancements in Bovine Organoid Technology Using Small and Large Intestinal Monolayer Interfaces

Our research goal is to establish robust techniques to generate staple intestinal monolayer interfaces derived from adult bovine small and large intestinal organoids. We employed a multimodal analytical approach to confirm the functional epithelial barrier formation within the established monolayers. Unlike three-dimensional models, 2D monolayers offer an exposed, accessible luminal surface crucial for studying host pathogen interactions.These monolayers reflecting the in vivo gut with multiple cell lineages now provide tailored protocols for investigating pathogens in specific gut sections such as small and large intestinal niches. Our research identified optimized culture conditions to create and sustain 2D monolayers from cells of bovine mall and large intestinal organoids. We confirmed the formation of functional epithelial barrier within these monolayers using transepithelial electrical registrants and paracellular permeability assays, as well as immunocytochemistry staining techniques.Our protocol addressed the research gap by focusing on the lack of intestinal organoid derived monolayer models of bovines. These models have been well studied in mice and humans, however, bovines, which are major reservoirs for intestinal pathogens with serious public health implications haven't been adequately explored. Our research establishes and characterizes a 2D bovine monolayer culture system.This innovative tool allows for the exploration of normal and disease states of bovine intestinal physiology, with potential applications extending into biomedical and translational research of public health significance.

Assessing Epithelial Barrier Integrity of Organoid-Derived 2D Monolayers Using Paracellular Permeability Assay

Research

JoVE Journal

Medicine

Advancing knowledge of gastrointestinal physiology and its diseases critically depends on the development of precise, species-specific in vitro models ...

Using Bovine Ileal and/or Rectal Organoids for Establishing 2D Monolayer Culture