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Published on: January 30, 2018
Endotoxins Induced ECM-Receptor Interaction Pathway Signal Effect on the Function of MUC2 in Caco2/HT29 Co-Culture
Wenxiang Hu1, Ping Feng2, Mingming Zhang1
1College of Animal Veterinary Medicine, Northwest A & F University, Yanling City, China.
Abstract:
Endotoxins are toxic substances that widely exist in the environment and can enter the intestine with food and other substances. Intestinal epithelial cells are protected by a mucus layer that contains MUC2 as its main structural component. However, a detailed understanding of the mechanisms involved in the function of the mucus barrier in endotoxin penetration is lacking. Here, we established the most suitable proportion of Caco-2/HT-29 co-culture cells as a powerful tool to evaluate the intestinal mucus layer. Our findings significantly advance current knowledge as focal adhesion and ECM-receptor interaction were identified as the two most significantly implicated pathways in MUC2 small interfering RNA (siRNA)-transfected Caco-2/HT-29 co-culture cells after 24 h of LPS stimulation. When the mucus layer was not intact, LPS was found to damage the tight junctions of Caco-2/HT29 co-cultured cells. Furthermore, LPS was demonstrated to inhibit the integrin-mediated focal adhesion structure and damage the matrix network structure of the extracellular and actin microfilament skeletons. Ultimately, LPS inhibited the interactive communication between the extracellular matrix and the cytoskeleton for 24 h in the siMUC2 group compared with the LPS(+) and LPS(-) groups. Overall, we recognized the potential of MUC2 as a tool for barrier function in several intestinal bacterial diseases.
Insights
This study reveals how MUC2 mucus protects the gut barrier from endotoxins like LPS. Disrupting MUC2 allows LPS to damage intestinal cells by affecting focal adhesion and ECM-receptor interactions.
Area of Science:
- Gastroenterology
- Cell Biology
- Immunology
Background:
- Endotoxins, such as lipopolysaccharide (LPS), are environmental toxins that can compromise intestinal barrier integrity.
- The intestinal mucus layer, primarily composed of MUC2, serves as a crucial defense against endotoxin penetration.
- Mechanisms underlying the mucus barrier's role in preventing endotoxin passage remain incompletely understood.
Purpose of the Study:
- To investigate the role of MUC2 in intestinal mucus barrier function against endotoxin (LPS) penetration.
- To identify molecular pathways affected by LPS when the MUC2 mucus layer is compromised.
- To establish a Caco-2/HT-29 co-culture model for evaluating intestinal mucus barrier function.
Main Methods:
- Utilizing a Caco-2/HT-29 co-culture system to model the intestinal mucus layer.
- Employing MUC2 small interfering RNA (siRNA) to disrupt the mucus barrier.
- Stimulating cells with LPS and analyzing pathway involvement via transcriptomic analysis (e.g., pathway enrichment).
- Assessing tight junction integrity and cytoskeletal/extracellular matrix structure post-LPS exposure.
Main Results:
- Focal adhesion and ECM-receptor interaction pathways were significantly implicated in MUC2-depleted cells after LPS stimulation.
- LPS exposure damaged tight junctions in Caco-2/HT-29 cells when the mucus layer was compromised.
- LPS inhibited integrin-mediated focal adhesion, disrupted extracellular matrix and actin cytoskeleton networks, and impaired ECM-cytoskeleton communication in siMUC2 cells.
Conclusions:
- MUC2 plays a vital role in maintaining intestinal barrier function against endotoxin damage.
- Disruption of the MUC2 mucus layer by LPS leads to significant cellular and molecular damage.
- MUC2 holds potential as a therapeutic target for managing intestinal diseases associated with bacterial toxins.
