Pathogenic Wnt-beta catenin target genes in macrophages and fibrosis

系统性硬化症(SSC)/硬皮病，是引起皮肤和内脏的典型纤维性疾病 纤维化症。随着患者年龄的增长，肺纤维化进展是SSc相关死亡的主要原因。很可能是 一种常见的效应细胞在SSC的多个器官中驱动纤维化，我们的初步数据表明 循环中的单核细胞被招募到受损组织中，在那里它们分化为“单核细胞来源”。 巨噬细胞。使用肺纤维化的小鼠模型，我们进行了因果遗传学实验，并显示 这些单核细胞来源的组织巨噬细胞对纤维化的发展至关重要。不偏不倚 小鼠肺纤维化期间流式单核细胞来源的肺泡巨噬细胞的转录图谱，以及 在来自SSC移植患者的肺移植的人肺泡巨噬细胞中，显示 通过Wnt/β-连环蛋白通路改变信号传导。我们发现Wnt/β-连环蛋白的遗传功能缺失 小鼠肺巨噬细胞中的信号并不影响纤维化的严重程度，但加速了纤维化的消退。这些 这些发现让人想起那些在老年动物身上的发现，在博莱霉素组中，纤维化持续的时间更长 给药与幼龄小鼠比较。事实上，损伤后持续的纤维化是一个特征。 人体多脏器纤维化的特点。此外，我们还发现Wnt/β-连接蛋白随年龄的变化 流式分选肺泡巨噬细胞产生的转录本中的途径成分 小鼠寿命(4-24个月)。这些发现支持了我们的假设，即Wnt/β-连锁素的功能增强 单核细胞来源的巨噬细胞中的信号转导与增龄相关的持续性纤维化易感性有关 多个器官。我们建议在两个相互关联的具体目标上检验这一假设。在目标1中，我们将 确定单核细胞来源的Wnt/β-连环蛋白信号的遗传获得或功能丧失 巨噬细胞增强或抑制老年动物对多器官的不同易感性 纤维化症。在目标2中，我们将确定一个常见的失控的Wnt途径相关基因的表达 从SSc患者的肺和皮肤分离的组织巨噬细胞中存在特征 健康受试者。我们之前的工作使用了小鼠和SSC患者的全皮肤活组织检查， 证明Wnt/β-catenin系统的改变与SSc真皮纤维化有关。我们现在 建议利用我们在巨噬细胞生物学和WNT/β-连环蛋白信号转导方面的综合专业知识 确定它们在老年人加速的SSc皮肤和肺纤维化中的作用。总之，这项提议 将一个经过验证的调查团队与一个令人信服的假设相匹配，该假设将改变我们的思维方式 关于衰老相关的纤维化。

Systemic sclerosis (SSc)/scleroderma, is the prototypic fibrotic disease causing skin and internal organ fibrosis. Lung fibrosis progression as a patient ages is the leading cause of SSc-related deaths. It is likely that a common effector cell drives fibrosis in multiple organs in SSc, and our preliminary data demonstrate that circulating monocytes are recruited to injured tissues where they differentiate into “monocyte-derived” macrophages. Using a murine model of lung fibrosis, we performed causal genetic experiments and showed that these monocyte-derived tissue macrophages are critical for the fibrosis development. Unbiased transcriptional profiling of flow-sorted monocyte-derived alveolar macrophages in mice during lung fibrosis, and in human alveolar macrophages from lung explants from patients with SSc undergoing transplantation, showed altered signaling through the Wnt/β-catenin pathway. We found that genetic loss-of- function in Wnt/β-catenin signaling in murine lung macrophages did not affect fibrosis severity, but sped the resolution of fibrosis. These findings are reminiscent of those in aged animals in which fibrosis persists much longer after bleomycin administration compared with young mice. Indeed, the persistence of fibrosis after injury is a characteristic feature of human fibrosis in multiple organs. Furthermore, we found age-related changes in Wnt/β-catenin pathway components in transcriptomes generated from flow sorted alveolar macrophages collected over the lifespan of mice (4-24 months). These findings support our hypothesis that a gain of function in Wnt/β-catenin signaling in monocyte-derived macrophages contributes to the age-related susceptibility to persistent fibrosis in multiple organs. We propose to test this hypothesis in two interrelated specific aims. In Aim 1, we will determine whether genetic gain- or loss-of-function of Wnt/β-catenin signaling in monocyte-derived macrophages cells enhances or prevents the differential susceptibility of aged animals to multiple organ fibrosis. In Aim 2, we will determine whether a common deregulated Wnt pathway-related gene expression signature is present in tissue macrophages isolated from the lung and skin of patients with SSc compared to healthy control subjects. Our previous work using whole skin biopsies from mice and SSc patients, demonstrated that alterations in the Wnt/β-catenin system are involved with SSc dermal fibrosis. We now propose to capitalize upon our combined expertise in macrophage biology and Wnt/β-catenin signaling to determine their contribution to accelerated SSc dermal and lung fibrosis in the aged. Altogether, this proposal matches a proven investigative team with a compelling hypothesis that stands to transform the way we think about aging-related fibrosis.