Department of Materials, Wolfgang-Pauli-Strasse 10, HCI F 443 ETH Zurich, CH-8093 Zurich, Switzerland.
Integr Biol (Camb). 2009 Dec;1(11-12):635-48. doi: 10.1039/b914996a. Epub 2009 Oct 27.
Elevated levels of tissue crosslinking are associated with numerous diseases (cancer stroma, organ fibrosis), and also eliminate the otherwise remarkable clinical successes of tissue-derived scaffolds, instead eliciting a foreign body reaction. Nevertheless, it is not well understood how the initial physical and biochemical properties of cellular microenvironments, stem cell niches, or of 3D tissue scaffolds guide the assembly and remodeling of new extracellular matrix (ECM) that is ultimately sensed by cells. Here, we incorporated FRET-based mechanical strain sensors, either into cell-derived ECM scaffolds or into the fibronectin (Fn) matrix assembled by reseeded fibroblasts, and demonstrated the following. Cell-generated tensile forces change the conformation of Fn in both 3D scaffolds and new matrix over time. The time course by which new matrix fibers are stretched by reseeded cells is accelerated by scaffold crosslinking. Importantly, stretching Fn fibers increases their elastic modulus (rigidity) and alters their biochemical display. Regulated by Fn fiber unfolding, more soluble Fn binds to the native than to the crosslinked scaffolds. Additionally, matrix assembly of fibroblasts is decreased by scaffold crosslinking. Taken together, scaffold crosslinking has a multifactorial impact on the microenvironment that reseeded cells assemble and respond to, with far-reaching implications for tissue engineering and disease physiology.
细胞外基质（ECM）的组装和重塑最终由细胞感知，但细胞外基质交联如何影响细胞外基质的组装和重塑，目前人们对此知之甚少。在这里，我们将基于荧光共振能量转移（FRET）的力学应变传感器分别整合到细胞衍生的 ECM 支架或重新接种的成纤维细胞组装的纤连蛋白（Fn）基质中，并证明了以下几点。随着时间的推移，细胞产生的拉伸力会改变 3D 支架和新基质中 Fn 的构象。细胞拉伸新基质纤维的时间进程会因支架交联而加速。重要的是，拉伸 Fn 纤维会增加其弹性模量（刚性）并改变其生化表现。受 Fn 纤维展开的调节，更多可溶性 Fn 与天然而非交联支架结合。此外，支架交联会减少成纤维细胞的基质组装。总之，支架交联对重新接种细胞组装和响应的微环境具有多方面的影响，对组织工程和疾病生理学具有深远的意义。
