P. aeruginosa Infected 3D Co-Culture of Bronchial Epithelial Cells and Macrophages at Air-Liquid Interface for Preclinical Evaluation of Anti-Infectives
June 15th, 2020
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We describe a protocol for a three-dimensional co-culture model of infected airways, using CFBE41o- cells, THP-1 macrophages, and Pseudomonas aeruginosa, established at the air-liquid interface. This model provides a new platform to simultaneously test antibiotic efficacy, epithelial barrier function, and inflammatory markers.
Overview
This article presents a robust and reproducible in vitro co-culture model that mimics human cystic fibrosis bronchial mucosa infected by Pseudomonas aeruginosa under air-liquid interface (ALI) conditions. The model combines human bronchial epithelial cells (CFBE41o-) and THP-1 monocyte-derived macrophages, enabling simultaneous assessment of epithelial barrier integrity, macrophage transmigration, bacterial survival, and inflammation. This system is designed to facilitate the evaluation of anti-infective drug efficacy and host responses, potentially improving the translation of new therapies for lung infections.
Key Study Components
Area of Science
- Infectious disease research
- Cell biology
- Pharmacology
- Respiratory disease modeling
Background
- Traditional in vivo models for cystic fibrosis lung infections do not fully replicate human disease conditions or treatment outcomes.
- Complex in vitro models using human cells can better mimic the lung microenvironment and host-pathogen interactions.
- Bacterial infections in the lung involve both epithelial barrier disruption and immune cell responses.
- There is a need for predictive models to evaluate anti-infective drugs and optimize their delivery, especially via aerosolization.
Purpose of Study
- To establish a human cell-based co-culture model that simulates cystic fibrosis bronchial infection by P. aeruginosa at ALI.
- To enable simultaneous monitoring of epithelial barrier function, immune cell migration, bacterial survival, and inflammatory responses.
- To provide a platform for testing the efficacy of anti-infective drugs and their delivery methods.
Methods Used
- Cultivation of CFBE41o- bronchial epithelial cells and THP-1 monocyte-derived macrophages.
- Establishment of ALI conditions on permeable supports to mimic airway exposure.
- Infection of co-cultures with P. aeruginosa (PAO1-GFP) at a defined multiplicity of infection.
- Assessment of epithelial barrier integrity via transepithelial electrical resistance (TEER) and ZO-1 immunostaining.
- Measurement of macrophage transmigration and bacterial uptake.
- Evaluation of bacterial survival using CFU assays and confocal microscopy.
- Testing of drug treatments (e.g., tobramycin) and potential for aerosol delivery.
Main Results
- The co-culture model successfully mimics key aspects of cystic fibrosis airway infection, including epithelial barrier compromise and immune cell migration.
- TEER measurements and ZO-1 staining confirm barrier integrity and its disruption upon infection.
- Macrophage transmigration and bacterial uptake are observed, with timing differences between monoculture and co-culture conditions.
- Drug treatment with tobramycin reduces bacterial proliferation initially, but bacteria can recover after prolonged exposure.
- The model allows for assessment of both host and pathogen responses to infection and treatment.
Conclusions
- This human cell-based co-culture model provides a physiologically relevant platform for studying lung infections and evaluating anti-infective therapies.
- The system enables detailed analysis of epithelial barrier function, immune responses, and bacterial survival under conditions that closely mimic the human airway.
- It offers potential for optimizing aerosol drug delivery and advancing translational research in respiratory infections.
Frequently Asked Questions
What cell types are used in this co-culture model?
The model uses CFBE41o- human bronchial epithelial cells and THP-1 monocyte-derived macrophages.
How is the air-liquid interface (ALI) established in the model?
ALI is created by removing medium from the apical side of the permeable support, exposing the epithelial cells to air while maintaining medium on the basal side.
What pathogen is used to model infection?
The model uses Pseudomonas aeruginosa (PAO1-GFP) to simulate infection of the bronchial mucosa.
How is epithelial barrier integrity assessed?
Barrier integrity is measured using transepithelial electrical resistance (TEER) and immunostaining for tight junction protein ZO-1.
What parameters can be evaluated with this model?
The model allows assessment of epithelial barrier integrity, macrophage transmigration, bacterial survival, and inflammatory responses.
Can this model be used to test aerosolized drug delivery?
Yes, the model is compatible with aerosol administration, enabling evaluation of drug efficacy under physiologically relevant conditions.
What are the advantages of using this human cell-based model over animal models?
This model avoids species differences, better mimics human airway physiology, and allows for more predictive assessment of drug efficacy and host-pathogen interactions.
Executive Industry Relevance
Predictive in vitro models that recapitulate human airway infection and immune response are critical for de-risking anti-infective drug candidates before preclinical advancement. This 3D co-culture system enables simultaneous assessment of epithelial barrier integrity, immune cell migration, and bacterial survival, directly supporting translational continuity and target validation for respiratory anti-infectives. Its compatibility with aerosol delivery workflows positions it as a strategic asset for portfolio triage and early go/no-go decisions in respiratory drug discovery.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Enables interrogation of host-pathogen interactions in a human-relevant airway context.
- Supports biological de-risking by modeling epithelial barrier disruption and immune response.
- Facilitates functional target validation for anti-infective mechanisms.
- Provides predictive confidence for candidate selection in cystic fibrosis and related indications.
Screening & Assay Development
- Prepares validated co-culture systems for quantitative assessment of drug efficacy.
- Standardizes measurement of TEER, macrophage transmigration, and bacterial CFU for reproducibility.
- Enables scalable screening of compounds with physiologically relevant endpoints.
- Supports assay readiness for both submersed and aerosolized drug delivery formats.
Translational & Preclinical Research
- Aligns with disease-relevant human airway biology for translational biomarker development.
- Bridges discovery and preclinical validation by modeling infection and immune response dynamics.
- Reduces risk of species-specific artifacts seen in animal models.
- Enables risk-adjusted advancement of anti-infective candidates with improved predictive value.
Pipeline & Workflow Integration
This co-culture model integrates into the discovery-to-preclinical continuum for respiratory anti-infectives, supporting both early mechanistic studies and preclinical candidate evaluation.
- Discovery Biology: Provides a platform for hypothesis testing of host-pathogen and drug interactions in human airway tissue.
- Screening: Delivers reproducible, quantitative outputs for epithelial integrity, immune migration, and bacterial survival.
- Analytics: Enables statistical comparison of drug effects on barrier function and infection outcomes.
- Translational Research: Facilitates alignment with clinical biomarkers and disease-relevant endpoints.
- Enterprise Reuse: Offers a reusable, modular system adaptable to various pathogens and drug modalities.
Operational & Enterprise Impact
- Scientific Value: Increases predictive confidence and reduces mechanistic ambiguity in anti-infective R&D.
- Operational Value: Standardizes complex co-culture workflows for reproducibility and scalability.
- Strategic Value: Improves go/no-go decision quality and capital efficiency by modeling human-relevant infection biology.
- Portfolio Impact: Enables risk-adjusted prioritization and advancement of respiratory anti-infective candidates.
Implementation Considerations
- Requires expertise in human cell culture, co-culture techniques, and infection modeling.
- Needs access to TEER measurement, confocal microscopy, and CFU quantification infrastructure.
- Demands rigorous cross-team standardization for reproducible outputs.
- Adaptable to other airway pathogens or immune cell types with protocol optimization.
- Careful handling of permeable supports and cell seeding is essential for model integrity.
Biopharma FAQs
Why does null hypothesis testing of TEER measurements matter for target validation?
Null hypothesis testing of TEER measurements enables objective assessment of whether candidate anti-infectives preserve or restore epithelial barrier integrity compared to controls. This statistical rigor is essential for validating mechanistic targets and reducing false positives in early-stage screening. Reliable TEER data support confident advancement decisions in the discovery pipeline.
How does isolation of macrophage transmigration inform the discovery pipeline?
Isolating macrophage transmigration quantifies immune cell response to infection and drug treatment, clarifying the contribution of immune modulation to therapeutic efficacy. This insight helps de-risk candidate selection by distinguishing direct antimicrobial effects from host-mediated responses. It strengthens mechanistic understanding at the target validation stage.
What do quantitative CFU measurements enable in anti-infective evaluation?
Quantitative CFU measurements provide direct, reproducible readouts of bacterial survival and proliferation under drug treatment. These outputs enable robust comparison of compound efficacy and inform dose-response relationships. Accurate CFU data are critical for prioritizing candidates with true anti-infective activity.
Why are replication requirements for TEER and CFU critical for cross-functional collaboration?
Replication of TEER and CFU measurements ensures data reliability and reproducibility across teams, facilitating transparent decision-making and cross-site comparability. Consistent replication supports alignment between discovery, screening, and translational research groups. It underpins enterprise-wide confidence in model outputs.
What statistical analysis capabilities are required before implementing this co-culture model?
Implementation requires statistical tools for analyzing TEER, CFU, and transmigration data, including hypothesis testing and variance analysis. These capabilities enable rigorous evaluation of drug effects and model performance. Robust analytics are essential for supporting go/no-go decisions and regulatory documentation.
Chapters in this video
0:04
Introduction
1:26
Growth and Differentiation of Cells in Permeable Support Inserts
5:29
Infection by P. aeruginosa
7:00
Measurement of Bacterial Proliferation via Colony-forming Units (CFU)
8:00
Results: Epithelial-macrophage Co-cultures Infected with P. aeruginosa
9:48
Conclusion
