REGULATION OF PAI I AND LIVER PATHOLOGY IN THE AGED

PAI I 的调节与老年人肝脏病理学

• 批准号: 6029787
• 负责人: CAROLYN J BRUZDZINSKI
• 金额: $ 10.5万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-08-01 至 2002-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6029787
• 关键词: age difference; aging; cell growth regulation; gene expression; genetic regulatory element; hepatectomy; hepatocyte growth factor; hormone regulation /control mechanism; in situ hybridization; laboratory rat; liver cells; liver regeneration; northern blottings; plasminogen activator inhibitors; transcription factor; transforming growth factors

Hepatic compensatory growth (HCG), or liver regeneration, is a critical physiological response to liver injury, disease or liver resection. The capacity for HCG diminishes with age, causing complications in individuals with liver disease or undergoing hepatic resection for treatment of hepatocellular carcinoma. Plasminogen activator inhibitor type 1 (PAI-1) is an immediate early gene expressed during HCG in the two month old rat. There are age-dependent changes in plasma PAI-1 and in both plasminogen activators, but little is known about hepatic PAI-1 gene expression or age-related alternations of its expression during HCG. The two primary mediators of HCG, hepatocyte growth factor (HCG) and transforming growth factor type beta (TGF-beta), can regulate PAI-1 gene expression in certain cell lines, but nothing is known about their capacity to regulate PAI-1 in primary hepatocytes. HGF and TGF-beta must be proteolytically cleaved for activation; components of plasminogen activation can accomplish this activation. Since PAI-1 is a primary modulator of plasminogen activation, it may serve to regulate the balance of mature HGF and TGF-beta by regulating their maturation. Such a feedback loop would connect a triad involving HGF, TGF-beta and PAI-1 which could function in the control of the initiation and progression of HCG. In this model, alterations in the regulation of any of these molecules would result in aberrations in HCG, as observed in the aged. The objective of this proposal is to test the hypotheses first, that the expression of PAI-1 during liver regeneration is altered with increasing age; and second, that the alterations in the expression of hepatic PAI-1 are due to age-dependent changes in the mechanisms of regulation of PAI-1 by HGF and TGF-beta. The regulation of PAI-1 gene expression during liver regeneration in the aged rat will be analyzed by studies of hepatic growth following 70% partial hepatectomy. The kinetics and site of mRNA induction will be determined by Northern blot analysis and in situ hybridization. The regulation of PAI-1 gene expression by HGF and TGF-beta will be studied in primary cultures of young and aged rat hepatocytes. Regulatory mechanisms will be studied by analysis of gene transcription and mRNA stability, as well as identification of the cis-acting DNA sequences and trans-acting proteins involved. Specific DNA protein interactions identified will be compared to those observed in vivo during liver regeneration. Age-dependent alterations of hepatic PAI-1 synthesis potentially may effect the balance of the major mediators of HCG. Understanding the mechanisms of regulation of PAI-1 during liver regeneration may allow the development of new strategies for management of liver disease in the aged.

肝脏代偿性生长(Hcg)或肝再生是一个关键因素。 对肝脏损伤、疾病或肝切除的生理反应。这个 人绒毛膜促性腺激素的容量随着年龄的增长而减少，导致 患有肝病或正在接受肝切除的个人 肝细胞癌的治疗。纤溶酶原激活物抑制物 1型(PAI-1)是一种在HCG期间表达的即刻早期基因 一个月大的老鼠。血浆纤溶酶原激活物-1和血管紧张素转换酶原激活物抑制物-1和 两种纤溶酶原激活物，但对肝脏PAI-1基因知之甚少 在人绒毛膜促性腺激素过程中其表达或与年龄相关的变化。这个 人绒毛膜促性腺激素的两种主要介体，肝细胞生长因子和 转化生长因子β(TGF-β)，可调节PAI-1基因 在某些细胞系中表达，但对它们的 原代肝细胞调节PAI-1的能力。肝细胞生长因子和转化生长因子-β必须 被蛋白质分解以激活；纤溶酶原成分 激活可以完成这种激活。由于PAI-1是主要的 纤溶酶原激活的调节剂，可能起到调节平衡的作用 通过调节成熟的肝细胞生长因子和转化生长因子-β来调节其成熟。这样的一个 反馈环将连接涉及HGF、转化生长因子-β和纤溶酶原激活物-1的三联体 它可能在控制血管紧张素转换酶的启动和进展中发挥作用。 HCG。在这个模型中，对其中任何一个的监管变化 正如在老年人观察到的那样，分子会导致HCG的异常。 这项提议的目标是首先检验假设，即 肝再生过程中纤溶酶原激活物-1的表达 其次，肝组织PAI-1表达的变化 是由于PAI-1调节机制的年龄相关性变化 肝细胞生长因子和转化生长因子-β。 大鼠肝再生过程中PAI-1基因表达的调控 老年大鼠将通过70%以下的肝脏生长研究进行分析 肝部分切除术。信使核糖核酸诱导的动力学和位置将是 经Northern印迹分析和原位杂交鉴定。这个 肝细胞生长因子和转化生长因子β对PAI-1基因表达的调节作用将被研究 在幼年和老年大鼠肝细胞原代培养中。监管 机制将通过基因转录和信使核糖核酸的分析来研究。 稳定性，以及鉴定顺式作用的DNA序列和 参与反式作用的蛋白质。特异的DNA蛋白质相互作用 将与活体肝脏观察到的结果进行比较 再生。 肝脏PAI-1合成的年龄相关性改变可能 影响人绒毛膜促性腺激素主要介质的平衡。了解 肝再生过程中PAI-1的调节机制可能允许 制定新的肝病管理策略 年纪大了。