Ethanol Effects on the Transcriptional Regulatory Network in Liver Regeneration

 描述（由申请人提供）：肝再生是临床上重要的组织修复过程，其中肝脏通过驱动分化的肝细胞的同步复制来响应损伤。该过程涉及来自不同细胞类型的精心编排的信号与系统因子的相互作用，以恢复功能性组织块。肝脏再生受到慢性酒精消耗的抑制，这种受损的修复反应可能会导致酒精性肝病的风险。再生反应的发生和进展及其由乙醇引起的失调的机制仍然缺乏表征。在先前的研究中，我们对乙醇喂养和对照大鼠中70%部分肝切除术（PHx）后的再生反应进行了详细的基因表达和microRNA分析研究，并开发了新的生物信息学工具来突出细胞类型特异性转录组特征。这些研究表明，慢性乙醇处理影响控制肝细胞引发和复制的非实质细胞（NPC），并且与肝星状细胞（HSC）活化特征的上调相关。我们获得的证据表明，miR-21可能是这些差异反应的驱动因素。通过用AM 21（一种特异性miR-21拮抗剂）治疗来抑制大鼠体内的miR-21，允许乙醇喂养大鼠的肝再生恢复，同时抑制差异HSC活化谱。在本申请中，我们基于这些发现，使用激光捕获显微切割（LCM）分析不同细胞类型如何促进整合的组织反应，并通过计算建模方法整合实验数据，以预测再生如何通过适应慢性乙醇暴露而受到抑制，以及如何通过miR-21抑制而得到拯救。(1)我们将分析乙醇喂养和对照大鼠的时间再生动力学，并分析AM 21治疗的差异影响，以表征有助于乙醇介导的肝再生抑制的miR-21靶向过程，重点关注NPC对细胞周期进程的贡献。我们将进一步比较大鼠和小鼠的肝再生模型，以评估miR-21与细胞周期调节因子的相互作用在对PHx有不同时间反应的动物中的差异。(2)我们将测试的假设，适应乙醇消费改变了不同类型的细胞在肝脏中的时间响应，解除调节的综合组织反应，通过分析细胞类型特异性的变化，在乙醇喂养的动物相比，通过分析使用LCM获得的单个细胞的转录组和microRNA表达。(3)我们将应用细胞类型特异性相互作用在肝再生中的作用的计算模型来迭代地评估表型分布动态变化的后果。我们的综合实验和计算分析将产生新的见解调控miRNA网络驱动细胞表型分布和细胞-细胞相互作用，以及通过这些网络中的干预措施可以对抗乙醇诱导的肝脏修复抑制的机制，并应用于广泛的肝脏疾病的翻译和临床干预。

 DESCRIPTION (provided by applicant): Liver regeneration is a clinically important tissue repair process in which the liver responds to injury by driving a synchronized replication of differentiated liver cells. The process involves the interplay of carefully orchestrated signals frm different cell types integrated with systemic factors to recover functional tissue mass. Liver regeneration is inhibited by chronic ethanol consumption and this impaired repair response may contribute to the risk for alcoholic liver disease. The mechanisms responsible for the onset and progression of the regenerative response and its deregulation by ethanol remain poorly characterized. In prior studies we carried out a detailed gene expression and microRNA profiling study of the regeneration response after 70% partial hepatectomy (PHx) in ethanol-fed and control rats and developed novel bioinformatics tools to highlight cell- type specific transcriptomic signatures. These studies indicate that chronic ethanol treatment affects non- parenchymal cells (NPCs) that control hepatocyte priming and replication and is associated with upregulation of a hepatic stellate cell (HSC) activation signature. We obtained evidence that miR-21 may be a driver of these differential responses. Inhibition of miR-21 in the rat in vivo by treatment with AM21, a specific miR-21 antagonist, allowed recovery of liver regeneration in ethanol-fed rats while suppressing the differential HSC activation profile. In the current application we build on these findings to analyze how different cell types contribute to the integrated tissue response using laser capture microdissection (LCM) and integrating the experimental data through a computational modeling approach to predict how regeneration is inhibited by adaptation to chronic ethanol exposure and rescued by miR-21 inhibition. (1) We will analyze the temporal regeneration dynamics in ethanol-fed and control rats and profile the differential impact of AM21 treatment to characterize the miR-21 target processes that contribute to the ethanol-mediated inhibition of liver regeneration, with a focus on the contribution of NPCs to cell cycle progression. We will further compare rat and mouse models of liver regeneration to evaluate how miR-21's interactions with cell cycle regulators differs in animals that have a different temporal response to PHx. (2) We will test the hypothesis that the adaptation to ethanol consumption alters the temporal response of different cell types in the liver, deregulating the integrated tissue response, by analyzing cell type-specific changes in the transcriptome and microRNA expression in ethanol-fed animals compared to controls by analyzing individual cells obtained using LCM. (3) We will apply a computational model of the role of cell-type specific interactions in liver regeneration to iteratively evaluate the consequences of dynamic changes in phenotype distribution. Our integrated experimental and computational analysis will yield new insights into the regulatory miRNA network driving cell phenotype distributions and cell-cell interactions, and the mechanisms through which interventions in these networks can counter ethanol-induced suppression of liver repair, with applications to translational and clinical interventions i in a broad range of liver diseases.