Osteoblast plasticity during zebrafish regeneration

成熟成熟细胞的去分化是一种令人着迷的生物学现象，对于各种器官的再生是必不可少的，但其调控和分子基础尚不清楚。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骨骼的再生，这一过程似乎将高度再生的斑马鱼与哺乳动物区分开来。我们最近还发现，NF-κB信号在成骨细胞内自主地作用于细胞，以抑制其去分化，但我们尚未确定介导其作用的途径的靶点。我们未发表的初步数据表明，成骨细胞在鳍的动态平衡、去分化和再生鳍的再分化过程中具有高度的异质性。在这里，我们建议使用单细胞RNA-seq和ATAC-seq方法来解决成骨细胞在动态平衡、去分化和再分化过程中的异质性，并在去分化过程中推断转录和染色质景观动态。此外，我们还将确定成骨细胞中NF-κB信号的下游效应因子。我们预计，这些强大的单细胞方法将通过鉴定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控的分子洞察。

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 Our preliminary unpublished data suggest that osteoblasts are highly heterogenous during fin homeostasis, during dedifferentiation and during redifferentiation in the regenerating fin.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.