Cai Linyi, Liu Wenjing, Cui Yujia, Liu Yang, Du Wei, Zheng Liwei, Pi Caixia, Zhang Demao, Xie Jing, Zhou Xuedong
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China.
ACS Biomater Sci Eng. 2020 Aug 10;6(8):4476-4489. doi: 10.1021/acsbiomaterials.0c00367. Epub 2020 Jul 31.
The exquisite cartilage architecture maintains an orderly dynamic equilibrium as a result of the interplay between chondrocyte functions and the unique extracellular matrix (ECM) microenvironment. Numerous studies have demonstrated that extracellular cues, including topological, mechanical, and biochemical properties of the underlying substrates, dictate the chondrocyte behaviors. Consequently, developing advanced biomaterials with the desired characteristics which could achieve the biointerface between cells and the surrounded matrix close to the physiological conditions becomes a great hotspot in bioengineering. However, how the substrate stiffness influences the intercellular communication among chondrocytes is still poorly reported. We used polydimethylsiloxane with varied stiffnesses as a cell culture substrate to elucidate a novel cell-to-cell communication in a collective of chondrocytes. First, morphological images collected using scanning electron microscopy revealed that the tunable substrate stiffnesses directed the changes in intercellular links among chondrocytes. Next, fibronectin, which played a vital role in the connection of ECM components or linkage of ECM to chondrocytes, was shown to be gathered along cell-cell contact areas and was changed with the tunable substrate stiffnesses. Furthermore, transmembrane junctional proteins including connexin 43 (Cx43) and pannexin 1 (Panx1), which are responsible for gap junction formation in cell-to-cell communication, were mediated by the tunable substrate stiffnesses. Finally, through a scrape loading/dye transfer assay, we revealed cell-to-cell communication changes in a living chondrocyte population in response to the tunable substrate stiffnesses cell-to-cell fluorescent molecule transport. Taken together, this novel cell-to-cell communication regulated by biomaterial stiffness could help us to increase the understanding of cell behaviors under biomechanical control and may ultimately lead to refining cell-based cartilage tissue engineering.
由于软骨细胞功能与独特的细胞外基质（ECM）微环境之间的相互作用，精致的软骨结构维持着有序的动态平衡。大量研究表明，包括底层基质的拓扑、机械和生化特性在内的细胞外信号决定了软骨细胞的行为。因此，开发具有所需特性、能够在接近生理条件下实现细胞与周围基质之间生物界面的先进生物材料，成为生物工程领域的一大热点。然而，关于底物硬度如何影响软骨细胞间的细胞间通讯，目前报道仍较少。我们使用具有不同硬度的聚二甲基硅氧烷作为细胞培养底物，以阐明软骨细胞群体中的一种新型细胞间通讯。首先，使用扫描电子显微镜收集的形态学图像显示，可调节的底物硬度引导了软骨细胞间细胞连接的变化。其次，在ECM成分连接或ECM与软骨细胞连接中起关键作用的纤连蛋白，沿细胞间接触区域聚集，并随可调节的底物硬度而变化。此外，包括连接蛋白43（Cx43）和泛连接蛋白1（Panx1）在内的跨膜连接蛋白，在细胞间通讯中负责间隙连接的形成，也受可调节的底物硬度介导。最后，通过刮擦加载/染料转移试验，我们揭示了活软骨细胞群体中细胞间通讯随可调节的底物硬度发生的变化——细胞间荧光分子运输。综上所述，这种由生物材料硬度调节的新型细胞间通讯有助于我们加深对生物力学控制下细胞行为的理解，并最终可能有助于改进基于细胞的软骨组织工程。
