Osteoblast plasticity during zebrafish regeneration

成熟成体细胞的去分化是一种迷人的生物学现象，对于各种器官的再生至关重要，但其调控和分子基础却知之甚少。我们之前已经发现，成熟的成骨细胞去分化有助于斑马鱼鳍中的骨再生，这一过程似乎将高度再生的斑马鱼与哺乳动物区分开来。我们最近也发现NF-κB信号传导在成骨细胞内自主作用于细胞以抑制其去分化，但我们尚未确定介导其作用的通路靶点。我们的初步未发表的数据表明，成骨细胞是高度异质性在鳍稳态，在去分化和再分化过程中再生鳍。在这里，我们建议使用单细胞RNA-seq和ATAC-seq的方法来解决成骨细胞异质性在稳态，去分化和再分化，并推导出转录和染色质景观动态去分化。此外，我们还将鉴定成骨细胞中NF-κB信号传导的下游效应物。我们期望这些强大的单细胞方法将通过识别以前未表征的亚群来揭示新的成骨细胞生物学，并将导致对去分化调节的分子洞察。

Dedifferentiation of mature adult cells is a fascinating biological phenomenon that is essential for regeneration of a variety of organs, yet its regulation and molecular underpinnings are poorly understood. We have previously found that mature osteoblasts dedifferentiate to contribute to regeneration of bone in the zebrafish fin, a process that seems to set the highly regenerative zebrafish apart from mammals. We have also recently shown that NF-κB signaling acts cells autonomously within osteoblasts to inhibit their dedifferentiation, but we have not yet identified targets of the pathway mediating its role. Our preliminary unpublished data suggest that osteoblasts are highly heterogenous during fin homeostasis, during dedifferentiation and during redifferentiation in the regenerating fin. Here we propose to use single cell RNA-seq and ATAC-seq approaches to resolve osteoblast heterogeneity during homeostasis, dedifferentiation and redifferentiation, and to deduce transcriptional and chromatin landscape dynamics during dedifferentiation. In addition, we will identify downstream effectors of NF-κB signaling in osteoblasts. We expect that these powerful single cell approaches will reveal novel osteoblast biology by identifying previously uncharacterized subpopulations, and will result in molecular insight into the regulating of dedifferentiation.