Mesenchymal Stem Cell Mechanics from the Attached to the Suspended State
Mesenchymal Stem Cell Mechanics from the Attached to the Suspended State
复制标题
DOI：
10.1016/j.bpj.2010.08.052
复制
发表时间：
2010-10-20
影响因子：
3.4
通讯作者：
Van Vliet, Krystyn J.
中科院分区：
文献类型：
--
作者：
Maloney, John M.;Nikova, Dessy;Van Vliet, Krystyn J.
人间充质干细胞（hMSC）是治疗上有用的细胞，其通常在再植入之前在刚性基质上体外扩增。在这里，我们通过原子力显微镜和光学拉伸在延长传代过程中探索MSC的机械和结构变化，并且我们证明了附着的MSC群体的细胞骨架组织和机械刚度在体外超过15个群体倍增时受到强烈调节。细胞骨架肌动蛋白网络表现出显着的粗化，伴随着这些细胞的平均机械顺应性和分化潜力下降，虽然分子表面标记物的表达并没有显着下降。这些机械变化在悬浮状态下没有观察到，表明这些变化表现为应力纤维排列的改变，而不是皮质细胞骨架排列的改变。此外，光学拉伸能够研究以前未量化的结构转变：贴壁细胞悬浮后数十分钟内重塑诱导的硬化。最后，我们发现，光学拉伸hMSCs表现出幂律流变学在加载和恢复过程中，这一证据似乎是第一个起源于生物物理测量技术，不涉及细胞探针或细胞基质接触。总之，这些对附着和悬浮的MSC的定量评估定义了细胞外环境的极端，同时探测了有助于细胞机械反应的细胞内机制。
Human mesenchymal stem cells (hMSCs) are therapeutically useful cells that are typically expanded in vitro on stiff substrata before reimplantation. Here we explore MSC mechanical and structural changes via atomic force microscopy and optical stretching during extended passaging, and we demonstrate that cytoskeletal organization and mechanical stiffness of attached MSC populations are strongly modulated over >15 population doublings in vitro. Cytoskeletal actin networks exhibit significant coarsening, attendant with decreasing average mechanical compliance and differentiation potential of these cells, although expression of molecular surface markers does not significantly decline. These mechanical changes are not observed in the suspended state, indicating that the changes manifest themselves as alterations in stress fiber arrangement rather than cortical cytoskeleton arrangement. Additionally, optical stretching is capable of investigating a previously unquantified structural transition: remodeling-induced stiffening over tens of minutes after adherent cells are suspended. Finally, we find that optically stretched hMSCs exhibit power-law rheology during both loading and recovery; this evidence appears to be the first to originate from a biophysical measurement technique not involving cell-probe or cell-substratum contact. Together, these quantitative assessments of attached and suspended MSCs define the extremes of the extracellular environment while probing intracellular mechanisms that contribute to cell mechanical response.