BRIEF RESEARCH REPORT article
Front. Med.
Sec. Pulmonary Medicine
Volume 12 - 2025 | doi: 10.3389/fmed.2025.1552803
This article is part of the Research TopicNext Generation In Vitro Models to Study Chronic Pulmonary Diseases - Volume IIView all 6 articles
Dynamic mechanical stimulation of alveolar epithelial-fibroblast models using the Flexcell tension system to study lung disease mechanisms
Provisionally accepted
- University of British Columbia, Okanagan Campus, Kelowna, Canada
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Mechanical strain plays a significant role in lung pathophysiology. Current 2D in vitro models fail to capture the lung's dynamic mechanical environment. We developed mechanically strained 2D and more complex three-dimensional (3D) alveolar epithelial-fibroblast co-cultures and organoids using the Flexcell cell stretching bioreactor. To achieve this, we utilized readily available human A549 epithelial cells and MRC-5 lung fibroblasts to establish 2D and 3D alveolar co-cultures and collagen-I-gel-embedded organoid models in the Flexcell. We then strained them at 18% amplitude and 0.4 Hz for 24 hours to mimic a pathological environment. The impact of mechanical strain on cell proliferation, morphology, cytoskeletal and tight junctional protein expression, IL-6, IL-8 release, and cell death was assessed. Mechanical strain significantly increased total cell counts in 3D but not 2D co-cultures, potentially signifying increased proliferation. Morphological analysis revealed a marked transition of fibroblasts into broadened shape cells under strain in the 3D co-cultures. This was in line with increased F-actin in 3D co-cultures after strain. The tight junctional protein zonula occludens-1 expression decreased after strain in all models. Furthermore, exposure to strain increased IL-6 and IL-8 release. Strain-induced cell death was also elevated across all models, particularly in 3D cultures. This study presents exploratory findings suggesting that in vitro mechanical multicellular alveolar models, utilizing the Flexcell system, may replicate the dynamic environment of in vivo lung tissue. These multicellular models offer a valuable platform for investigating strain-induced responses relevant to inflammatory and fibrotic mechanisms in lung diseases, particularly in exploring epithelial-mesenchymal interactions in disease.
Keywords: In vitro Models, Mechanical model, alveolar 3D epithelial-fibroblast model, Flexcell, multicellular 3D coculture and organoid models
Received: 29 Dec 2024; Accepted: 24 Jul 2025.
Copyright: © 2025 Al Yazeedi, Guo, Sohd, Abokor and Osei. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Emmanuel Twumasi Osei, University of British Columbia, Okanagan Campus, Kelowna, Canada
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