Hepatocyte Hippo Signaling Drives Inflammation in Liver Injury and Regeneration

项目摘要 这项提议的短期目标是定义肝细胞YAP信号如何影响募集和 肝损伤与再生过程中免疫细胞浸润的特点。我们的长期目标是 了解肝细胞与组织微环境之间的密切相互作用 肝纤维化。这个项目的成功完成将增强我们开发定制医疗的能力 通过专注于河马信号通路的特定手臂来治疗肝硬变。 几年来，我们主要研究了肝细胞在协调再生反应中所起的作用。 通过河马信号的镜头，一个强大的生长调节途径。在先前的提案(K08DK105351)中， 我们发现，通过诱导靶向肝细胞YAP的表达，这迅速导致了肝脏炎症和 纤维化症。我们预测，以类似的方式，慢性肝损伤会增加肝细胞YAP的活性，并 这将直接导致肝脏炎症/纤维化的发展。我们随后确认了 这项研究的预测。在这个过程中，我们发现炎症与体内的YAP水平直接相关 肝细胞和Cyr61是YAP的关键转录靶点，直接与巨噬细胞有关 细胞募集和肝纤维化。 这项提议试图通过使用新的工具来询问肝脏生物学来扩展这些发现。在目标1中，我们将 描述应答的单核/巨噬细胞的来源、表型和贡献 肝细胞特异性YAP(YAP-TG)活性在推动纤维化中的作用。使用化学和遗传的组合 改变单核/巨噬细胞活性的策略我们将定义它们在炎症/纤维化中的作用 YAP-TG的背景。在目标2中，我们将询问肝细胞衍生的Cyr61在招募和 通过体内过表达和基因敲除实验使单核细胞极化。质量细胞术和 高通量的RNA测序将被用来探测免疫格局和细胞的变化 在Cyr61功能丧失和获得的背景下的信号传递。 我们认为，肝细胞在损伤后主动驱动遗传程序，重塑其局部 微环境。肝细胞YAP活性在指导这些程序中起着关键作用，Cyr61是一种 尤其重要的下游细胞因子。对正则和非正则机制的理解 YAP/Cyr61招募和极化免疫细胞环境将导致改进的模型 预测肝脏对疾病的反应，促进对肝硬变的定向治疗。

Project Summary The short-term goal of this proposal is to define how hepatocyte Yap signaling influences the recruitment and characteristics of immune cell infiltration during liver injury and regeneration. Our long-term goal is to understand the intimate cell-cell interactions that hepatocytes have with the tissue microenvironment to drive liver fibrosis. Successful completion of this project would augment our ability to develop tailored medical therapies for cirrhosis by focusing on particular arms of the Hippo Signaling pathway. For several years, we studied the role that hepatocytes play in orchestrating regenerative responses, primarily through the lens of Hippo Signaling, a potent growth regulatory pathway. In a prior proposal (K08DK105351), we identified that by inducibly targeting hepatocytic Yap expression, this rapidly led to liver inflammation and fibrosis. We predicted that in a similar fashion, chronic liver injury would increase hepatocytic Yap activity and that this would directly lead to the development of liver inflammation/fibrosis. We have subsequently confirmed the predictions of that study. In the process, we identified that inflammation is directly related to Yap levels in hepatocytes and that Cyr61 is a key transcriptional target of Yap that is directly responsible for macrophage cell recruitment and liver fibrosis. This proposal seeks to extend these findings by using new tools to interrogate liver biology. In Aim 1, we will characterize the origin, phenotype and contribution of the monocytes/macrophages that respond to hepatocyte-specific Yap (Yap-Tg) activity in driving fibrosis. Using a combination of chemical and genetic strategies to modify monocytes/macrophages activity we will define their contribution to inflammation/fibrosis in the context of Yap-Tg. In Aim 2, we will interrogate the role of hepatocyte-derived Cyr61 in recruiting and polarizing monocytes through in vivo overexpression and genetic knockout experiments. Mass cytometry and high throughput RNA sequencing will be used to probe the immune landscape and changes in cellular signaling in the context of Cyr61 loss and gain of function. We propose that hepatocytes actively drive genetic programs after injury that remodel their local microenvironment. Hepatocytic Yap activity plays a critical role in directing these programs with Cyr61 being a particularly important downstream cytokine. Understanding the canonical and non-canonical mechanisms by which Yap/Cyr61 recruit and polarize the immune cell environment will lead to improved models of predicting the liver’s response to disease and facilitate directed treatment for cirrhosis.