Project 2 - Macrophage regulation of fibrosis and scarring during tissue regeneration

项目2（Godwin）项目摘要 人类缺乏无疤痕愈合和再生，严重限制了功能性 重大创伤、手术干预和疾病后的恢复。大多数成人默认伤口修复 人体组织启动蛋白质/碳水化合物纤维化网络的形成 功能失调的疤痕组织在心脏、肺和肝脏等器官中，疤痕组织的形成可能是致命的， 占美国死亡人数的45%。开发激活再生和无疤痕的疗法 人体修复程序将改变现代医疗保健。 与人类和大多数其他哺乳动物不同，蝾螈能够无疤痕再生。 几乎所有复杂的组织，包括四肢、心脏、大脑和脊髓。以蝾螈为模型 系统，我们最近首次证明了先天免疫系统在调节 无疤痕再生具体来说，我们发现：1）巨噬细胞早期浸润到受损肢体或 心脏组织主动抑制纤维化，和2）抑制纤维化是 正常的再生。 巨噬细胞抑制损伤后纤维化的细胞和分子机制是 完全未知本提案的总体目标是开始界定这些机制， 首次使用蝾螈肢体再生作为模型系统。开发治疗方法， 通过调节巨噬细胞功能来抑制纤维化可以使受损细胞无瘢痕修复和再生 人体组织。 我们的建议将是第一个定义蝾螈巨噬细胞如何抑制肌成纤维细胞诱导 和疤痕组织形成。我们将使用谱系追踪方法来确定疤痕产生细胞的来源， 其是抗纤维化巨噬细胞信号传导的细胞靶。然后我们将定义巨噬细胞 抑制肌成纤维细胞诱导和纤维化激活信号的亚型。使用RNA测序，我们将 表征抑制肌成纤维细胞诱导的巨噬细胞中的基因表达模式。这些研究 将提供第一个机制的见解，抗纤维化信号通路，使巨噬细胞支持 无疤痕愈合最后，我们将检验永久性疤痕组织形成可能是可逆的这一假设 通过抑制赖氨酰氧化酶，一种介导细胞外基质交联的酶，反过来， 防止无疤痕愈合和再生。 这一建议既有意义又有创新性，因为它将解决我们对以下问题的理解方面的一个关键差距： 如何在高度再生的动物模型中克服纤维化和瘢痕形成。这些新的见解将 这是为患者开发抗纤维化和促再生疗法的重要一步。!

PROJECT 2 (Godwin) PROJECT SUMMARY The lack of scar-free healing and regeneration in humans imposes severe limitations on functional recovery after major traumatic injury, surgical interventions and disease. Default wound-repair in most adult human tissues initiates the formation of a protein/carbohydrate fibrotic network that progressively matures into dysfunctional scar tissue. In organs like the heart, lung and liver, formation of scar tissue can be deadly and contributes to ~45% of all U.S. deaths. Development of therapies that activate regeneration and scar-free repair programs in humans will transform modern healthcare. In contrast to humans and most other mammals, salamanders are capable of scar-free regeneration of almost all complex tissues including the limbs, heart, brain and spinal cord. Using the salamander as a model system, we recently demonstrated for the first time the critical role of the innate immune system in regulating scar-free regeneration. Specifically, we showed 1) that early infiltration of macrophages into damaged limb or heart tissue actively suppresses fibrosis and 2) that suppression of fibrosis is an essential step required for normal regeneration to occur. The cellular and molecular mechanisms by which macrophages suppress fibrosis after injury are completely unknown. The overarching goal of this proposal is to begin defining these mechanisms for the first time using salamander limb regeneration as a model system. Development of therapies that suppress fibrosis by modulating macrophage function may allow scar-free repair and regeneration of damaged tissues in humans. Our proposal will be the first to define how salamander macrophages suppress myofibroblast induction and scar tissue formation. We will use lineage tracing methods to identify the source of scar producing cells, which are the cellular targets of anti-fibrotic macrophage signaling. We will then define the macrophage subtypes that inhibit myofibroblast induction and fibrotic activation signals. Using RNA-sequencing, we will characterize gene expression patterns in macrophages that suppress myofibroblast induction. These studies will provide the first mechanistic insights into anti-fibrotic signaling pathways that allow macrophages to support scar-free healing. Finally, we will test the hypothesis that permanent scar tissue formation may be reversible by inhibition of lysyl oxidase, an enzyme that mediates crosslinking of the extracellular matrix, which, in turn, prevents scar-free healing and regeneration. This proposal is both significant and innovative as it will address a critical gap in our understanding of how fibrosis and scarring is overcome in a highly regenerative animal model. These new insights will form an essential step in the development of anti-fibrosis and pro-regenerative therapies for patients. !