Organ Model: Respiratory System

Organ Model: Lung (Alveolus)

Application: Infectious Disease

Abstract: The COVID-19 pandemic has highlighted the importance of physiologically relevant in vitro models to assist preclinical research. Here, we describe the adaptation of a human alveolus microphysiological system (MPS) model consisting of primary human alveolar epithelial and lung microvascular endothelial cells to study infection with SARS-CoV-2 at Biosafety Level 3 (BSL3) facility. This infection model recapitulates breathing-like stretch and culture of epithelial cells at the air-liquid interface (ALI) and resulted in clinically relevant cytopathic effects including cell rounding of alveolar type 2 cells (AT2) and disruption of the tight junction protein occludin (OCLN). Viral replication was confirmed by immunocytochemical nucleocapsid staining in the epithelium and increased shedding of SARS-CoV-2 virus within two days post-infection, associated with changes in innate host immune responses. Together, these data demonstrate that, under the experimental conditions used in this work, this human alveolus MPS chip can successfully model SARS-CoV-2 infection of human alveolar lung cells.

Featured session at Netherlands MPS Day, which took place on 11/15/2023.

Dr. Anne van der Does from Leiden University Medical Center presents work on modeling both airway and alveolar regions of the human lung using advanced in vitro systems, including Organ-on-a-Chip technology. The lung, a complex and heterogeneous organ, is composed of distinct epithelial cell populations and is continuously subjected to mechanical forces such as airflow and stretching during breathing. These factors differ between the large airways, small airways, and alveoli, and they strongly influence cellular maturation, function, and repair.

Her team’s research demonstrates that incorporating mechanical cues (e.g., airflow and cyclic stretch) into an airway epithelial chip model accelerates mucociliary clearance and enhances the directional beating of cilia, achieving a more physiologically mature state within a shorter timeframe than conventional static cultures. Similarly, alveolar region models are being developed using primary alveolar type II cells expanded in organoids and induced pluripotent stem cell (iPSC)-derived alveolar-like cells. This approach enables large-scale, long-term studies and even genetic manipulation via CRISPR-based gene editing. The goal is to create improved disease models for conditions like chronic obstructive pulmonary disease (COPD) and pulmonary fibrosis, incorporating additional cell types (endothelial and stromal cells), mechanical factors, and environmental exposures (e.g., cigarette smoke). Ultimately, these refined, human-relevant models allow more accurate investigation into lung development, disease progression, and the efficacy of potential therapeutics.

Key learnings from this presentation include:

• Physiological relevance of mechanical cues: Integrating airflow and stretching significantly improves airway epithelial maturation, enhancing mucociliary clearance and cilia orientation within a shorter culture period compared to static conditions.
• Complex lung modeling: Distinct lung regions (airways vs. alveoli) require unique culturing strategies. Region-specific cell isolation, differentiation protocols, and careful choice of mechanical parameters are essential for robust, functional models.
• Biological insights into lung diseases: Improved in vitro models, including those derived from primary or iPSC-derived alveolar cells, facilitate the study of chronic lung diseases and repair mechanisms at the cellular and tissue level.
• Scalability and genetic manipulation: Expanding primary alveolar cells and using iPSCs allow for large-scale disease modeling and gene editing approaches, enabling systematic exploration of disease-relevant genetic variants and testing of therapeutic strategies.
• Towards multi-cellular, more complex systems: Incorporating additional lung cell types (such as endothelial cells and stromal cells) and modeling pathological conditions (fibrosis, alveolar damage) paves the way for more comprehensive and predictive human lung models.

Featured session at Bethesda MPS Day, which took place on November 9, 2023.

Dr. Sushma Bhosle from the Integrated Research Facility (IRF) at NIAID/NIH presents her work on using Lung-Chip models in maximum biosafety containment (BSL-4) settings for studying high-risk viruses such as Nipah virus (NiV). Traditional preclinical models (e.g., simple 2D cell cultures or animal models) often fail to accurately predict human clinical outcomes, and there’s a need for more physiologically relevant, human-based systems. Microphysiological systems (MPS), like the Emulate Small Airway Lung-Chip, provide a complex, human-relevant platform that incorporates airway epithelium and microvascular endothelium under air-liquid interface and flow conditions.

Dr. Bhosle’s team validated a Small Airway Lung-Chip using human primary cells, confirming proper differentiation and expression of markers indicative of mature airway tissue. They infected these chips with Nipah virus under BSL-4 conditions and monitored viral replication, barrier integrity, and immune responses. Compared to traditional transwell assays, the Airway Lung-Chip supported robust viral replication across both apical and basal compartments, displayed increased barrier permeability changes, and allowed detailed observation of cytokine profiles and endothelial inflammation. Treatment with antiviral drugs, such as zotatifin (an mRNA translation inhibitor) and remdesivir, reduced viral burden and restored barrier function. The chips also enabled the study of donor-to-donor variability in immune and inflammatory responses, reflecting the personalized aspects of human disease.

Furthermore, incorporation of immune cells (neutrophils) into the chip environment showed that immune cell recruitment and cytokine release patterns differed markedly upon viral infection, emphasizing the importance of including immune components for a more comprehensive disease model. This approach sets the stage for using Lung-Chip systems in maximum containment labs to test therapeutics, explore patient-specific responses, and understand high-risk virus biology with greater predictive value for clinical outcomes.

Key learnings from this presentation include:

• High containment feasibility: The Airway Lung-Chip is successfully operated in BSL-4 conditions, enabling the study of severe pathogens like Nipah virus.
• Physiological complexity: Compared to transwells, MPS offer dynamic air-liquid interface, fluid flow, and mechanical stretch, better replicating human lung physiology and yielding more meaningful data on viral infection and tissue responses.
• Antiviral interventions: Testing antivirals directly on the chip shows how candidate drugs (zotatifin, remdesivir) impact viral replication, barrier integrity, and cytokine profiles in a human-relevant context.
• Donor variability and immune involvement: The system captures variations in immune and inflammatory markers between donors and highlights the critical role of immune cell infiltration in shaping virus-induced pathology.
• Broad potential applications: Beyond Nipah virus, these methods can extend to studying various high-risk pathogens, informing therapeutic development, and advancing precision medicine approaches in infectious diseases.

Featured session at Bethesda MPS Day, which took place on November 9, 2023.

Dr. Dylan Fudge from the U.S. Army DEVCOM Chemical Biological Center discusses the use of Organ-Chip models, specifically Emulate’s MPS platforms, to advance the Army’s predictive toxicology efforts related to chemical and biological threats. Traditional safety and efficacy assessments often rely heavily on animal models and simplistic in vitro assays, which may not accurately reflect human physiology, particularly for acute, high-risk agents. By integrating human-relevant cells into microfluidic devices, Dr. Fudge’s team aims to improve mechanistic understanding, dose-response assessments, and long-term impact evaluations of nerve agents, PFAS compounds, and pathogens like SARS-CoV-2.

He showcases three major projects:

1. VX Nerve Agent on Liver-Chip:
   Exposing a human Liver-Chip (with hepatocytes, endothelial cells, stellates, and Kupffer cells) to sub-lethal VX concentrations allowed for multi-omics analyses (proteomics, metabolomics, and transcriptomics). The system revealed shifts in metabolic pathways, bioenergetics, and nitrogen metabolism consistent with in vivo and clinical literature. Importantly, VX’s known mechanism—disruption of acetylcholine breakdown—was mirrored in altered choline metabolism, reinforcing the Liver-Chip’s translational relevance.
2. PFAS Exposure in Kidney and Liver-Chips:
   Investigating polyfluoroalkyl substances (PFAS), the team saw patterns of compound retention and toxicity aligned with known clinical effects. Liver and Kidney-Chips demonstrated differential absorption and metabolic responses to PFAS, supported by robust omics data. Oxygen stress markers and biomarkers like uric acid levels recapitulated known toxicity profiles, indicating the chips’ capacity to model chronic, low-level exposures and related subtler health effects.
3. SARS-CoV-2 Infection Using Lung-Chips:
   Lung-Chips incorporating airway and alveolar regions enabled controlled infection with SARS-CoV-2 variants. Despite minimal acute cytotoxicity, omics analyses detected hallmark inflammatory pathways and mechanistic insights matching emerging clinical findings—such as immune activation and potential neuro-related disease pathways—emphasizing the chip’s ability to reveal complex host-pathogen interactions.

Collectively, these studies highlight the versatility and reliability of Emulate’s Organ-Chip platforms under rigorous defense-oriented research conditions. Their capacity to maintain viable tissues, capture human-like biology, and provide high-content data (via omics) positions these systems as valuable tools to reduce animal use, support therapeutic development, and enhance understanding of chemical and biological threat agents at a mechanistic level.

Organ Model: Lung (Alveolus)

Application: Infectious Disease

Abstract: Mycobacterium tuberculosis (Mtb) cultured axenically without detergent forms biofilm-like cords, a clinical identifier of virulence. In lung-on-chip (LoC) and mouse models, cords in alveolar cells contribute to suppression of innate immune signaling via nuclear compression. Thereafter, extracellular cords cause contact-dependent phagocyte death but grow intercellularly between epithelial cells. The absence of these mechanopathological mechanisms explains the greater proportion of alveolar lesions with increased immune infiltration and dissemination defects in cording-deficient Mtb infections. Compression of Mtb lipid monolayers induces a phase transition that enables mechanical energy storage. Agent-based simulations demonstrate that the increased energy storage capacity is sufficient for the formation of cords that maintain structural integrity despite mechanical perturbation. Bacteria in cords remain translationally active despite antibiotic exposure and regrow rapidly upon cessation of treatment. This study provides a conceptual framework for the biophysics and function in tuberculosis infection and therapy of cord architectures independent of mechanisms ascribed to single bacteria.

Organ Model: Lung (Alveolus)

Application: Toxicology

Abstract: Acute exposure to high-dose gamma radiation due to radiological disasters or cancer radiotherapy can result in radiation-induced lung injury (RILI), characterized by acute pneumonitis and subsequent lung fibrosis. A microfluidic organ-on-a-chip lined by human lung alveolar epithelium interfaced with pulmonary endothelium (Lung Alveolus Chip) is used to model acute RILI in vitro. Both lung epithelium and endothelium exhibit DNA damage, cellular hypertrophy, upregulation of inflammatory cytokines, and loss of barrier function within 6 h of radiation exposure, although greater damage is observed in the endothelium. The radiation dose sensitivity observed on-chip is more like the human lung than animal preclinical models. The Alveolus Chip is also used to evaluate the potential ability of two drugs – lovastatin and prednisolone – to suppress the effects of acute RILI. These data demonstrate that the Lung Alveolus Chip provides a human relevant alternative for studying the molecular basis of acute RILI and may be useful for evaluation of new radiation countermeasure therapeutics

Abstract

The need for human-centric model systems that can test the efficacy of chimeric antigen receptor (CAR) therapies is expanding rapidly, as these hold great promise for cancer treatment. We recently developed a system for inflammatory immune cell recruitment on the human Colon Intestine-Chip as a model for inflammatory bowel disease (IBD). The goal of the current study was to develop a novel system for measuring the recruitment and killing capacity of CAR-T cells in an Organ-Chip system.

Our proof-of-concept findings herein suggest that the human-centric Organ-Chip model can evaluate the efficacy of CAR-T cell therapies, and in particular, provide a system that integrates both the recruitment and killing aspects of CAR-T function. 

ScienceDirect (2021)

Abstract

Read this publication to learn how researchers built a prototype Chip-A1 Accessible Chip to address many of the challenges associated with the Organ-on-a-Chip technology, including incorporation of a tissue-specific extracellular matrix gel seeded with primary stromal cells, to reproducing the architectural complexity of tissues by micropatterning the gel, to extracting the gel for H&E staining.

To learn more about these findings, view our webinar “Organ-Chips 201: The Importance of Flow, Stretch, and Stroma for in vitro Modeling”.

Organ Model: Lung (Airway)

Application: Model Development

Abstract: Human lung function is intricately linked to blood flow and breathing cycles, but it remains unknown how these dynamic cues shape human airway epithelial biology. Here we report a state-of-the-art protocol for studying the effects of dynamic medium and airflow as well as stretch on human primary airway epithelial cell differentiation and maturation, including mucociliary clearance, using an organ-on-chip device. Perfused epithelial cell cultures displayed accelerated maturation and polarization of mucociliary clearance, and changes in specific cell-types when compared to traditional (static) culture methods. Additional application of airflow and stretch to the airway chip resulted in an increase in polarization of mucociliary clearance towards the applied flow, reduced baseline secretion of interleukin-8 and other inflammatory proteins, and reduced gene expression of matrix metalloproteinase (MMP) 9, fibronectin, and other extracellular matrix factors. These results indicate that breathing-like mechanical stimuli are important modulators of airway epithelial cell differentiation and maturation and that their fine-tuned application could generate models of specific epithelial pathologies, including mucociliary (dys)function.

Organ Model: Lung (Alveolus) & Skin

Application: Model Development

Abstract: Nearly all human organs are lined with epithelial tissues, comprising one or multiple layers of tightly connected cells organized into three-dimensional (3D) structures. One of the main functions of epithelia is the formation of barriers that protect the underlining tissues against physical and chemical insults and infectious agents. In addition, epithelia mediate the transport of nutrients, hormones, and other signaling molecules, often creating biochemical gradients that guide cell positioning and compartmentalization within the organ. Owing to their central role in determining organ-structure and function, epithelia are important therapeutic targets for many human diseases that are not always captured by animal models. Besides the obvious species-to-species differences, conducting research studies on barrier function and transport properties of epithelia in animals is further compounded by the difficulty of accessing these tissues in a living system. While two-dimensional (2D) human cell cultures are useful for answering basic scientific questions, they often yield poor in vivo predictions. To overcome these limitations, in the last decade, a plethora of micro-engineered biomimetic platforms, known as organs-on-a-chip, have emerged as a promising alternative to traditional in vitro and animal testing. Here, we describe an Open-Top Organ-Chip (or Open-Top Chip), a platform designed for modeling organ-specific epithelial tissues, including skin, lungs, and the intestines. This chip offers new opportunities for reconstituting the multicellular architecture and function of epithelial tissues, including the capability to recreate a 3D stromal component by incorporating tissue-specific fibroblasts and endothelial cells within a mechanically active system. This Open-Top Chip provides an unprecedented tool for studying epithelial/mesenchymal and vascular interactions at multiple scales of resolution, from single cells to multi-layer tissue constructs, thus allowing molecular dissection of the intercellular crosstalk of epithelialized organs in health and disease.