In Vitro Gut Model to Assess Bacterial Adhesion and Internalization
JoVE Encyclopedia of Experiments
Microbiology
0 views • 2:44 min • March 31st, 2026
Begin with a Transwell insert containing a co-culture of epithelial and goblet-like cells.
Epithelial cells form tight junctions, while goblet-like cells produce mucus, replicating the in vivo intestinal epithelial barrier.
Take a suspension of the oral bacterial community that has been treated with simulated intestinal fluid to mimic small intestinal digestion.
Replace the media in the upper chamber with the bacterial suspension.
Incubate with shaking to facilitate bacterial adhesion and internalization.
Collect the media from the upper chamber containing non-adherent bacteria for subsequent viability assays.
Add a mucus-dissolving solution and incubate to solubilize the mucus and release the adhered bacteria.
Collect the solution for further analysis of bacterial viability and adhesion.
Wash the cells with buffer and add a detergent to dislodge them.
Collect the cell suspension.
Vortex the suspension to lyse the cells and release the internalized bacteria.
Centrifuge and collect the supernatant and cellular debris separately for further analysis.
After washing and adjusting the cell density of the small intestine digestion according to the text protocol, remove the apical medium from the transwell system, and add 1.5 milliliters of the bacterial suspension.
Co-culture the system under general cell-culture conditions for 2 hours. Add 0.5 milliliters of 10 millimolar n-acetylcysteine in HBSS to solubilize the mucus produced by the HT29-MTX and to recover the adhered bacteria.
Incubate the plates at 37 degrees Celsius for 1 hour under agitation. Recover the NAC-HBSS in a microcentrifuge tube, and use 1 milliliter of DPBS to wash the cells twice. Add 0.5 milliliters of 0.5% triton X-100 on top of the monolayers, and disrupt the cells by pipetting.
Then quickly recover the liquid in vortex for 1 minute. Speed is crucial to avoid damaging the bacterial cells with the detergent. Analyze the samples according to the text protocol.
Overview
This protocol demonstrates a method to assess bacterial adhesion and internalization in an in vitro gut model. It is significant for understanding bacterial interactions with intestinal epithelial cells, which is crucial for gastrointestinal health.
Key Study Components
Area of Science
- Microbiology
- Cell Biology
- Gastroenterology
Background
- The intestinal barrier is essential for maintaining gut health.
- Bacterial adhesion and internalization can influence gut microbiota dynamics.
- In vitro models help simulate in vivo conditions for research.
- This model uses epithelial and goblet-like cells to replicate the intestinal environment.
Purpose of Study
- To evaluate how bacteria adhere to and internalize in intestinal cells.
- To understand the mechanisms of bacterial interactions with the gut barrier.
- To provide insights into potential therapeutic targets for gastrointestinal diseases.
Methods Used
- Co-culture of epithelial and goblet-like cells in a Transwell insert.
- Incubation with a bacterial suspension treated to mimic intestinal digestion.
- Use of mucus-dissolving solutions to recover adhered bacteria.
- Cell lysis and analysis of internalized bacteria.
Main Results
- This protocol demonstrates the recovery of adhered bacteria from epithelial cells.
- It outlines methods for analyzing bacterial viability post-internalization.
- It provides a framework for studying bacterial behavior in a controlled environment.
- Further analysis can reveal insights into bacterial-host interactions.
Conclusions
- The in vitro gut model is effective for studying bacterial adhesion and internalization.
- Understanding these processes can inform therapeutic strategies for gut health.
- This model can be adapted for various bacterial species and conditions.
Frequently Asked Questions
Executive Industry Relevance
This in vitro gut model enables mechanistic de-risking of bacterial-host interactions critical for microbiome-targeted therapeutics. By quantifying adhesion and internalization, it supports target validation and lead identification in preclinical discovery. The system provides quantitative, reproducible outputs that improve predictive confidence in early-stage pipeline decisions.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Scientific Value: Interrogates therapeutic hypotheses regarding bacterial virulence and commensalism mechanisms.
- Operational Value: Enables functional target validation by isolating bacterial adhesion and internalization phenotypes.
- Strategic Value: Supports predictive confidence and portfolio triage through quantitative host-microbe interaction data.
Screening & Assay Development
- Scientific Value: Prepares validated biological systems for downstream antimicrobial or probiotic screening campaigns.
- Operational Value: Standardizes assay conditions via Transepithelial Electrical Resistance (TEER) monitoring and defined fractionation workflows.
- Strategic Value: Enhances screening readiness and scalability through compartmentalized recovery of media, mucus, lysate, and debris fractions.
Translational & Preclinical Research
- Scientific Value: Aligns with disease-relevant systems by modeling the human intestinal barrier using Caco-2/HT29-MTX co-culture.
- Operational Value: Ensures translational continuity from discovery through preclinical validation via standardized bacterial recovery protocols.
- Strategic Value: Informs risk-adjusted advancement decisions by measuring bacterial viability post-internalization.
Pipeline & Workflow Integration
The method integrates into the discovery continuum from hypothesis testing to lead identification, providing mechanistic insights that de-risk biological targets before compound screening.
- Discovery Biology: Supports hypothesis testing and pathway clarification by isolating variables in bacterial adhesion and internalization processes.
- Screening: Delivers assay readiness and quantitative outputs through defined collection of non-adherent, adhered, and internalized bacterial fractions.
- Analytics: Enables comparative analysis via viability assays on media, mucus-solubilized, lysate, and debris samples.
- Translational Research: Connects to preclinical continuity through reproducible modeling of the gut host-microbe interface.
- Enterprise Reuse: Functions as a reusable platform for evaluating diverse bacterial strains under standardized digestive conditions.
Operational & Enterprise Impact
- Scientific Value: Predictive confidence, target validation, reduction of mechanistic ambiguity in host-microbe interactions.
- Operational Value: Standardization, reproducibility, and scalability via TEER validation and compartmentalized sampling.
- Strategic Value: Better go/no-go decisions, capital efficiency, and reduced late-stage biological risk in microbiome programs.
- Portfolio Impact: Risk-adjusted prioritization and advancement decisions based on quantitative adhesion and internalization metrics.
Implementation Considerations
- Requires expertise in cell culture, Transwell systems, and anaerobic bacterial handling.
- Depends on instrumentation for TEER measurement, centrifugation, and vortexing.
- Necessitates cross-team standardization of mucus solubilization and detergent lysis timing.
- Involves adaptation considerations for varying bacterial species and simulated digestive conditions.
- Practical limitations include potential shear stress during agitation and detergent sensitivity of certain bacterial strains.
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Last updated: 22 August 2026