Owing to their self-renewal and multi-lineage differentiation capability, mesenchymal stem cells (MSCs) hold enormous potential in regenerative medicine. A prerequisite for a successful MSC therapy is the rigorous investigation of their function after in vitro cultivation. Damages introduced to mitochondria during cultivation adversely affect MSCs function and can determine their fate. While it has been shown that microtubules and vimentin intermediate filaments are important for mitochondrial dynamics and active mitochondrial transport within the cytoplasm of MSCs, the role of filamentous actin in this process has not been fully understood yet. To gain a deeper understanding of the interdependence between mitochondrial function and the cytoskeleton, we applied cytochalasin B to disturb the filamentous actin-based cytoskeleton of MSCs. In this study we combined conventional functional assays with a state-of-the-art oxygen sensor-integrated microfluidic device to investigate mitochondrial function. We demonstrated that cytochalasin B treatment at a dose of 16 μM led to a decrease in cell viability with high mitochondrial membrane potential, increased oxygen consumption rate, disturbed fusion and fission balance, nuclear extrusion and perinuclear accumulation of mitochondria. Treatment of MSCs for 48 h ultimately led to nuclear fragmentation, and activation of the intrinsic pathway of apoptotic cell death. Importantly, we could show that mitochondrial function of MSCs can efficiently recover from the damage to the filamentous actin-based cytoskeleton over a period of 24 h. As a result of our study, a causative connection between the filamentous actin-based cytoskeleton and mitochondrial dynamics was demonstrated.

由于其自我更新和多谱系分化能力，间充质干细胞 (MSCs) 在再生医学中具有巨大的潜力。成功的 MSC 治疗的先决条件是在体外后对其功能的严格研究栽培。在培养过程中引入线粒体的损​​伤会对 MSC 的功能产生不利影响，并可以决定它们的命运。虽然已经表明微管和波形蛋白中间丝对 MSC 细胞质内的线粒体动力学和主动线粒体转运很重要，但丝状肌动蛋白在该过程中的作用尚未完全清楚。为了更深入地了解线粒体功能与细胞骨架之间的相互依赖性，我们应用细胞松弛素 B 来干扰 MSC 的丝状肌动蛋白细胞骨架。在这项研究中，我们将传统的功能测定与最先进的氧传感器集成微流体装置相结合，以研究线粒体功能。我们证明，16 μM 剂量的细胞松弛素 B 处理导致细胞活力降低，线粒体膜电位高，耗氧率增加，融合和裂变平衡紊乱，核挤压和线粒体的核周积累。MSCs 处理 48 小时最终导致核碎裂，并激活凋亡细胞死亡的内在途径。重要的是，我们可以证明 MSC 的线粒体功能可以在 24 小时内有效地从对基于丝状肌动蛋白的细胞骨架的损伤中恢复。作为我们研究的结果，证实了基于丝状肌动蛋白的细胞骨架和线粒体动力学之间的因果关系。线粒体的核挤压和核周积累。MSCs 处理 48 小时最终导致核碎裂，并激活凋亡细胞死亡的内在途径。重要的是，我们可以证明 MSC 的线粒体功能可以在 24 小时内有效地从对基于丝状肌动蛋白的细胞骨架的损伤中恢复。作为我们研究的结果，证实了基于丝状肌动蛋白的细胞骨架和线粒体动力学之间的因果关系。线粒体的核挤压和核周积累。MSCs 处理 48 小时最终导致核碎裂，并激活凋亡细胞死亡的内在途径。重要的是，我们可以证明 MSC 的线粒体功能可以在 24 小时内有效地从对基于丝状肌动蛋白的细胞骨架的损伤中恢复。作为我们研究的结果，证实了基于丝状肌动蛋白的细胞骨架和线粒体动力学之间的因果关系。