Defining key differences in mouse fibroblasts during digit regeneration and fibrosis

项目总结 哺乳动物的复合组织再生非常有限；然而，人类和小鼠可以完全再生。 截肢后指尖的远端。这个过程涉及到胚泡的形成，细胞 这种结构是再生组织的来源，是成功再生不可或缺的一部分。近端 指甲以外的截肢不会形成胚芽，导致纤维性伤口愈合。这一差异 行为使小鼠指尖成为研究细胞和分子因素的理想模型系统 驱动每一种伤口愈合反应，以及为什么哺乳动物的复杂再生如此有限。具体来说， 本项目将侧重于成纤维细胞亚型及其在纤维化和再生中的作用。成纤维细胞是一种 胚泡的主要贡献者，在纤维化中起着不可或缺的作用；因此，它们可能是一个细胞群。 这推动了在纤维化和再生之间的决定。我们的单细胞转录(scRNA-seq) 对再生胚泡的分析表明，成纤维细胞群体是非常不同的， 在胚泡形成和发育过程中，亚群具有明显的种群动态和谱系轨迹。 成熟。我假设有特定的成纤维细胞亚型可以促进再生、抑制 纤维化，或两者兼而有之。然而，还没有研究通过追踪成纤维细胞来实现直接的血统贡献。 再生和纤维化中的亚群。此外，我们的体内功能作用和重要性 通过计算定义的促进再生的候选基因还没有确定。该项目将利用 基于单细胞CRISPR的DNA条形码在亚型分辨率下追踪成纤维细胞的谱系(目标1) 以及用于基因传递的质粒电穿孔以从功能上评估候选促再生基因(目的 2)。总之，我的两个目标将提供有关纤维化和再生过程的重要见解 在老鼠指尖确定，将为更有效的临床治疗开辟新的途径 人类的大伤口或截肢。

PROJECT SUMMARY Composite tissue regeneration is very limited in mammals; however, humans and mice can fully regenerate the distal tips of the digits following amputation. This process involves the formation of a blastema, a cellular structure that is the source of the regenerated tissue and is integral to successful regeneration. Proximal amputations beyond the nail do not form a blastema and result in fibrotic wound-healing. This differential behavior makes the mouse digit tip an ideal model system to investigate the cellular and molecular factors driving each wound-healing response and why complex regeneration is so limited in mammals. Specifically, this project will focus on fibroblast subtypes and their role in fibrosis versus regeneration. Fibroblasts are a major contributor to the blastema and play an integral part in fibrosis; thus, they may be a cell population that drives the decision between fibrosis and regeneration. Our single cell transcriptomic (scRNA-seq) analysis of the regenerating blastema revealed an extremely heterogenous fibroblast population and that the subpopulations had distinct population dynamics and lineage trajectories during blastema formation and maturation. I hypothesize that there are specific fibroblast subtypes that promote regeneration, inhibit fibrosis, or both. However, no studies have performed direct lineage contributions by tracing fibroblast subpopulations in regeneration and fibrosis. Additionally, the in vivo functional roles and importance of our computationally defined candidate pro-regenerative genes have not been established. This project will utilize single-cell CRISPR based DNA barcoding for lineage tracing fibroblasts at the subtype resolution (Aim 1) and plasmid electroporation for gene delivery to functionally assess candidate pro-regenerative genes (Aim 2). Together, my two aims will provide important insight into how the fibrotic and regenerative processes are determined in the mouse digit tip and will open additional avenues for more effective clinical treatments for large wounds or amputations in humans.