Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA 94720, USA.
Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA.
Sci Adv. 2024 Aug 2;10(31):eadk8232. doi: 10.1126/sciadv.adk8232.
While extracellular matrix (ECM) stress relaxation is increasingly appreciated to regulate stem cell fate commitment and other behaviors, much remains unknown about how cells process stress-relaxation cues in tissue-like three-dimensional (3D) geometries versus traditional 2D cell culture. Here, we develop an oligonucleotide-crosslinked hyaluronic acid-based ECM platform with tunable stress relaxation properties capable of use in either 2D or 3D. Strikingly, stress relaxation favors neural stem cell (NSC) neurogenesis in 3D but suppresses it in 2D. RNA sequencing and functional studies implicate the membrane-associated protein spectrin as a key 3D-specific transducer of stress-relaxation cues. Confining stress drives spectrin's recruitment to the F-actin cytoskeleton, where it mechanically reinforces the cortex and potentiates mechanotransductive signaling. Increased spectrin expression is also accompanied by increased expression of the transcription factor EGR1, which we previously showed mediates NSC stiffness-dependent lineage commitment in 3D. Our work highlights spectrin as an important molecular sensor and transducer of 3D stress-relaxation cues.
虽然细胞外基质 (ECM) 的弛豫越来越被认为可以调节干细胞命运的决定和其他行为，但关于细胞如何在类似于组织的三维 (3D) 几何形状中处理弛豫信号，而不是在传统的 2D 细胞培养中处理弛豫信号，还有很多未知之处。在这里，我们开发了一种具有可调节的弛豫特性的基于寡核苷酸交联透明质酸的 ECM 平台，可用于 2D 或 3D。引人注目的是，3D 中的弛豫有利于神经干细胞 (NSC) 的神经发生，而在 2D 中则抑制它。RNA 测序和功能研究表明，膜相关蛋白 spectrin 是 3D 中应激松弛信号的关键 3D 特异性转导器。限制应激会促使 spectrin 募集到 F-肌动蛋白细胞骨架，在那里它可以机械地增强皮质并增强机械转导信号。spectrin 的表达增加伴随着转录因子 EGR1 的表达增加，我们之前曾表明 EGR1 介导 NSC 在 3D 中的刚度依赖性谱系决定。我们的工作强调了 spectrin 作为 3D 应激弛豫信号的重要分子传感器和转导器。
