Department of Cell Biology, Regeneration Next, Duke University Medical Center, Durham, NC 27710, USA.
Department of Cell Biology, Regeneration Next, Duke University Medical Center, Durham, NC 27710, USA.
Curr Biol. 2018 Dec 17;28(24):3937-3947.e4. doi: 10.1016/j.cub.2018.10.052. Epub 2018 Nov 29.
Osteoblasts are matrix-depositing cells that can divide and heal bone injuries. Their deep-tissue location and the slow progression of bone regeneration challenge attempts to capture osteoblast behaviors in live tissue at high spatiotemporal resolution. Here, we have developed an imaging platform to monitor and quantify individual and collective behaviors of osteoblasts in adult zebrafish scales, skeletal body armor discs that regenerate rapidly after loss. Using a panel of transgenic lines that visualize and manipulate osteoblasts, we find that a founder pool of osteoblasts emerges through de novo differentiation within one day of scale plucking. These osteoblasts undergo division events that are largely uniform in frequency and orientation to establish a primordium. Osteoblast proliferation dynamics diversify across the primordium by two days after injury, with cell divisions focused near, and with orientations parallel to, the scale periphery, occurring coincident with dynamic localization of fgf20a gene expression. In posterior scale regions, cell elongation events initiate in areas soon occupied by mineralized grooves called radii, beginning approximately 2 days post injury, with patterned osteoblast death events accompanying maturation of these radii. By imaging at single-cell resolution, we detail acquisition of spatiotemporally distinct cell division, motility, and death dynamics within a founder osteoblast pool as bone regenerates.
成骨细胞是一种基质沉积细胞,能够分裂并修复骨骼损伤。由于其在组织深部的位置以及骨骼再生的缓慢过程,尝试在活体组织中以高时空分辨率捕获成骨细胞的行为极具挑战性。在这里,我们开发了一种成像平台,以监测和量化成年斑马鱼鳞片中成骨细胞的个体和集体行为,这些鳞片是在失去后能够快速再生的骨骼体甲盘。使用一组可可视化和操纵成骨细胞的转基因系,我们发现,在鳞片拔出后的一天内,通过从头分化出现了一个成骨细胞的创始池。这些成骨细胞经历分裂事件,其频率和方向在很大程度上是均匀的,以建立一个原基。在损伤后两天,成骨细胞增殖动态在原基内多样化,细胞分裂集中在鳞片边缘附近,并与鳞片边缘平行,与 fgf20a 基因表达的动态定位同时发生。在后部鳞片区域,细胞伸长事件在被称为半径的矿化沟槽占据的区域开始,大约在损伤后 2 天,伴随着这些半径的成熟,出现有模式的成骨细胞死亡事件。通过单细胞分辨率成像,我们详细描述了在骨骼再生过程中,创始成骨细胞池内获得的时空上不同的细胞分裂、迁移和死亡动力学。