Schamberger Barbara, Ehrig Sebastian, Dechat Thomas, Spitzer Silvia, Bidan Cécile M, Fratzl Peter, Dunlop John W C, Roschger Andreas
Department of the Chemistry and Physics of Materials, Paris-Lodron University of Salzburg, 5020 Salzburg, Austria.
Laboratory of Systems Biology of Gene Regulatory Elements, Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Hannoversche Str. 28, 10115 Berlin, Germany.
PNAS Nexus. 2024 Mar 21;3(4):pgae121. doi: 10.1093/pnasnexus/pgae121. eCollection 2024 Apr.
Little is known about the contribution of 3D surface geometry to the development of multilayered tissues containing fibrous extracellular matrix components, such as those found in bone. In this study, we elucidate the role of curvature in the formation of chiral, twisted-plywood-like structures. Tissues consisting of murine preosteoblast cells (MC3T3-E1) were grown on 3D scaffolds with constant-mean curvature and negative Gaussian curvature for up to 32 days. Using 3D fluorescence microscopy, the influence of surface curvature on actin stress-fiber alignment and chirality was investigated. To gain mechanistic insights, we did experiments with MC3T3-E1 cells deficient in nuclear A-type lamins or treated with drugs targeting cytoskeleton proteins. We find that wild-type cells form a thick tissue with fibers predominantly aligned along directions of negative curvature, but exhibiting a twist in orientation with respect to older tissues. Fiber orientation is conserved below the tissue surface, thus creating a twisted-plywood-like material. We further show that this alignment pattern strongly depends on the structural components of the cells (A-type lamins, actin, and myosin), showing a role of mechanosensing on tissue organization. Our data indicate the importance of substrate curvature in the formation of 3D tissues and provide insights into the emergence of chirality.
关于三维表面几何形状对包含纤维状细胞外基质成分的多层组织（如骨骼中的组织）发育的贡献，我们所知甚少。在本研究中，我们阐明了曲率在形成手性、扭曲胶合板状结构中的作用。将由小鼠前成骨细胞（MC3T3-E1）组成的组织在具有恒定平均曲率和负高斯曲率的三维支架上培养长达32天。使用三维荧光显微镜，研究了表面曲率对肌动蛋白应力纤维排列和手性的影响。为了获得机制上的见解，我们对缺乏核A型核纤层蛋白的MC3T3-E1细胞或用靶向细胞骨架蛋白的药物处理的细胞进行了实验。我们发现，野生型细胞形成了一个厚组织，其中纤维主要沿负曲率方向排列，但相对于较老的组织在方向上表现出扭曲。纤维方向在组织表面以下保持一致，从而形成一种扭曲胶合板状材料。我们进一步表明，这种排列模式强烈依赖于细胞的结构成分（A型核纤层蛋白、肌动蛋白和肌球蛋白），显示了机械传感在组织组织中的作用。我们的数据表明底物曲率在三维组织形成中的重要性，并为手性的出现提供了见解。
