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器官纤维化的典型疾病 纤维化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 一个共同的效应细胞驱动SSc多个器官的纤维化，我们的初步数据表明， 循环的单核细胞被募集到损伤的组织，在那里它们分化成"单核细胞衍生的" 巨噬细胞使用肺纤维化的小鼠模型，我们进行了因果遗传实验，并显示 这些单核细胞衍生的组织巨噬细胞对纤维化的发展至关重要。无偏 小鼠肺纤维化过程中流式分选单核细胞衍生的肺泡巨噬细胞的转录谱，以及 在来自接受移植的SSc患者的肺外植体的人肺泡巨噬细胞中，显示 通过Wnt/β-catenin途径改变信号传导。我们发现Wnt/β-catenin基因的功能缺失 鼠肺巨噬细胞中的信号传导不影响纤维化的严重程度，但加速了纤维化的消退。这些 这些发现让人联想到老年动物中博莱霉素治疗后纤维化持续时间更长的情况 与年轻小鼠相比。事实上，损伤后纤维化的持续是一个特征， 人类多器官纤维化的特征。此外，我们还发现Wnt/β-catenin的年龄相关性变化， 从收集的流式分选肺泡巨噬细胞产生的转录组中的途径组分 小鼠寿命（4 - 24个月）。这些发现支持了我们的假设，即Wnt/β-catenin功能的获得 单核细胞衍生的巨噬细胞中的信号传导有助于老年人对持续性纤维化的易感性， 多个器官我们建议在两个相互关联的具体目标来检验这一假设。在目标1中，我们 确定单核细胞源性肿瘤中Wnt/β-连环蛋白信号传导的遗传获得或丧失功能 巨噬细胞增强或防止老年动物对多种器官的不同易感性 纤维化在目标2中，我们将确定是否一个共同的失调Wnt途径相关的基因表达， 在从SSc患者的肺和皮肤中分离的组织巨噬细胞中， 健康对照组。我们之前的工作使用小鼠和SSc患者的整个皮肤活检， 表明Wnt/β-catenin系统的改变与SSc真皮纤维化有关。我们现在 我建议利用我们在巨噬细胞生物学和Wnt/β-catenin信号传导方面的综合专业知识， 确定它们对加速老年人SSc皮肤和肺纤维化的贡献。总的来说，这项提案 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，这个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.