Mesenchymal stem cells (MSCs) have been isolated from various mesodermal and ectodermal tissues. While the phenotypic and functional heterogeneity of MSCs stemming from their developmental origins has been acknowledged, the genetic and environmental factors underpinning these differences are not well-understood. Here, we investigated whether substrate stiffness mediated mechanical cues can directly modulate the development of ectodermal MSCs (eMSCs) from a precursor human neural crest stem cell (NCSC) population. We showed that NCSC-derived eMSCs were transcriptionally and functionally distinct from mesodermal bone marrow MSCs. eMSCs derived on lower substrate stiffness specifically increased their expression of the MSC marker, CD44 in a Rho-ROCK signaling dependent manner, which resulted in a concomitant increase in the eMSCs' adipogenic and chondrogenic differentiation potential. This mechanically-induced effect can only be maintained for short-term upon switching back to a stiff substrate but can be sustained for longer-term when the eMSCs were exclusively maintained on soft substrates. We also discovered that CD44 expression modulated eMSC self-renewal and multipotency via the downregulation of downstream platelet-derived growth factor receptor beta (PDGFRβ) signaling. This is the first instance demonstrating that substrate stiffness not only influences the differentiation trajectories of MSCs but also their derivation from upstream progenitors, such as NCSCs.

从各种中胚层和外胚层组织中分离出间充质干细胞（MSC）。尽管人们已经认识到MSCs起源于它们的表型和功能上的异质性，但是支撑这些差异的遗传和环境因素仍未得到很好的理解。在这里，我们调查了基质刚度介导的机械提示是否可以直接调节前体人类神经precursor干细胞（NCSC）群体的外胚层MSC（eMSC）的发展。我们表明，NCSC衍生的eMSCs在转录和功能上与中胚层骨髓MSCs不同。源自较低底物刚度的eMSC以Rho-ROCK信号依赖性方式特异性地增加了MSC标记CD44的表达，从而导致eMSC的伴随增加。成脂和成软骨分化潜能。这种机械诱导的效果只能在切换回硬质基材后短期内保持，而当eMSC仅在软质基材上保持时可以长期维持。我们还发现CD44表达通过下调下游血小板衍生的生长因子受体β（PDGFRβ）信号传导来调节eMSC的自我更新和多能性。这是首次证明底物刚度不仅影响MSC的分化轨迹，而且还影响它们来自上游祖细胞（如NCSC）的来源。这种机械诱导的效果只能在切换回硬质基材后短期内保持，而当eMSC仅在软质基材上保持时可以长期维持。我们还发现CD44表达通过下调下游血小板衍生的生长因子受体β（PDGFRβ）信号传导来调节eMSC的自我更新和多能性。这是首次证明底物刚度不仅影响MSC的分化轨迹，而且还影响它们来自上游祖细胞（如NCSC）的来源。这种机械诱导的效果只能在切换回硬质基材后短期内保持，而当eMSC仅在软质基材上保持时可以长期维持。我们还发现CD44表达通过下调下游血小板衍生的生长因子受体β（PDGFRβ）信号传导来调节eMSC的自我更新和多能性。这是首次证明底物刚度不仅影响MSC的分化轨迹，而且还影响它们来自上游祖细胞（如NCSC）的来源。