1 Department of Biology, Case Western Reserve University , Cleveland, Ohio.
2 Case Center for Multimodal Evaluation of Engineered Cartilage, Case Western Reserve University , Cleveland, Ohio.
Tissue Eng Part A. 2018 Aug;24(15-16):1218-1227. doi: 10.1089/ten.TEA.2017.0438. Epub 2018 Apr 23.
Human mesenchymal stem cell (hMSC)-based chondrogenesis is a key process used to develop tissue engineered cartilage constructs from stem cells, but the resulting constructs have inferior biochemical and biomechanical properties compared to native articular cartilage. Transforming growth factor β containing medium is commonly applied to cell layers of hMSCs, which aggregate upon centrifugation to form 3-D constructs. The aggregation process leads to a high cell density condition, which can cause nutrient limitations during long-term culture and, subsequently, inferior quality of tissue engineered constructs. Our objective is to modulate the aggregation process by targeting RhoA/ROCK signaling pathway, the chief modulator of actomyosin contractility, to enhance the end quality of the engineered constructs. Through ROCK inhibition, repression of cytoskeletal tension in chondrogenic hMSCs was achieved along with less dense aggregates with enhanced transport properties. ROCK inhibition also led to significantly increased cartilaginous extracellular matrix accumulation. These findings can be used to create an improved microenvironment for hMSC-derived tissue engineered cartilage culture. We expect that these findings will ultimately lead to improved cartilaginous tissue development from hMSCs.
基于人骨髓间充质干细胞（hMSC）的软骨形成是一种从干细胞开发组织工程化软骨构建体的关键过程，但与天然关节软骨相比，所得构建体的生物化学和生物力学性能较差。转化生长因子β（TGF-β）包含在培养基中，通常应用于 hMSC 的细胞层，在离心时聚集形成 3-D 构建体。聚集过程导致高细胞密度条件，在长期培养过程中会导致营养限制，从而导致组织工程构建体的质量较差。我们的目标是通过靶向 RhoA/ROCK 信号通路来调节聚集过程，RhoA/ROCK 信号通路是肌动球蛋白收缩性的主要调节剂，以提高工程化构建体的最终质量。通过 ROCK 抑制，在软骨形成的 hMSC 中实现了细胞骨架张力的抑制，并且聚集物密度更低，具有增强的传输特性。ROCK 抑制还导致软骨细胞外基质的积累显著增加。这些发现可用于为 hMSC 来源的组织工程化软骨培养创造一个改良的微环境。我们期望这些发现最终将导致 hMSC 来源的软骨组织的更好发展。
