Al Yazeedi Safiya, Guo Tony Ju Feng, Sohd Joban, Abokor Filsan Ahmed, Baher Janaeya Zuri, Yee Logan, Cheung Chung, Sin Don D, Osei Emmanuel Twumasi
Department of Biology, University of British Columbia - Okanagan Campus, Kelowna, BC, Canada.
Centre for Heart Lung Innovation, St. Paul's Hospital, Vancouver, BC, Canada.
Front Med (Lausanne). 2025 Aug 18;12:1552803. doi: 10.3389/fmed.2025.1552803. eCollection 2025.
Mechanical strain plays a significant role in lung pathophysiology. Current two-dimensional (2D) 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 do this we used 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 and then strained them at 18% amplitude, 0.4 Hz for 24 h to mimic a pathological environment. The impact of mechanical strain on cell proliferation, morphology, cytoskeletal and tight junctional protein expression, interleukin-6 and-8 (IL-6, IL-8) inflammatory cytokine release, and cell death were assessed. Mechanical strain significantly increased total cell counts in 3D co-cultures but not in 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 2D and 3D models. Furthermore, exposure to strain increased the release of IL-6 and IL-8. Strain-induced cell death was also elevated across all models, particularly in 3D cultures. This study presents exploratory findings suggesting that mechanical multicellular alveolar models using the Flexcell system may replicate the dynamic environment of lung tissue. These multicellular models offer a valuable platform for investigating strain-induced cellular responses relevant to inflammatory and fibrotic mechanisms in lung diseases, particularly in exploring epithelial-mesenchymal interactions that may underlie disease progression.
机械牵张在肺部病理生理学中起着重要作用。当前的二维（2D）模型无法捕捉肺部的动态力学环境。我们使用Flexcell细胞拉伸生物反应器开发了机械牵张的二维和更复杂的三维（3D）肺泡上皮-成纤维细胞共培养物及类器官。为此，我们使用易于获取的人A549上皮细胞和MRC-5肺成纤维细胞，在Flexcell中建立二维和三维肺泡共培养物以及胶原-I-凝胶包埋的类器官模型，然后以18%的振幅、0.4 Hz的频率对其进行24小时牵张，以模拟病理环境。评估了机械牵张对细胞增殖、形态、细胞骨架和紧密连接蛋白表达、白细胞介素-6和-8（IL-6、IL-8）炎性细胞因子释放以及细胞死亡的影响。机械牵张显著增加了三维共培养物中的总细胞数，但二维共培养物中未增加，这可能意味着增殖增加。形态学分析显示，在三维共培养物中，牵张下成纤维细胞明显转变为扁平状细胞。这与牵张后三维共培养物中F-肌动蛋白增加一致。在所有二维和三维模型中，牵张后紧密连接蛋白闭合蛋白-1的表达均降低。此外，暴露于牵张会增加IL-6和IL-8的释放。牵张诱导的细胞死亡在所有模型中也有所增加，尤其是在三维培养物中。本研究提出的探索性结果表明，使用Flexcell系统的机械多细胞肺泡模型可能复制肺组织的动态环境。这些多细胞模型为研究与肺部疾病炎症和纤维化机制相关的牵张诱导细胞反应提供了一个有价值的平台，特别是在探索可能构成疾病进展基础的上皮-间充质相互作用方面。
