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: 2732561
• 负责人: CAROLYN J BRUZDZINSKI
• 金额: $ 10.44万
• 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 2000-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2732561
• 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）或肝脏再生是一个关键 对肝损伤、疾病或肝切除的生理反应。 这 HCG 的能力随着年龄的增长而减弱，导致并发症 患有肝病或接受肝切除术的人 肝细胞癌的治疗。 纤溶酶原激活剂抑制剂 1 型 (PAI-1) 是 HCG 期间在两种细胞中表达的立即早期基因 月龄老鼠。 血浆 PAI-1 和血浆 PAI-1 存在年龄依赖性变化 两者都是纤溶酶原激活剂，但对肝脏 PAI-1 基因知之甚少 HCG 期间的表达或其与年龄相关的表达变化。 这 HCG 的两个主要介质，肝细胞生长因子 (HCG) 和 β型转化生长因子（TGF-β），可调节PAI-1基因 在某些细胞系中表达，但对它们的情况一无所知 调节原代肝细胞中 PAI-1 的能力。 HGF 和 TGF-β 必须 被蛋白水解裂解以激活；纤溶酶原的成分 激活可以完成此激活。 由于 PAI-1 是主要的 纤溶酶原激活调节剂，可能有助于调节平衡 通过调节成熟的 HGF 和 TGF-β 的成熟。 这样一个 反馈回路将连接涉及 HGF、TGF-β 和 PAI-1 的三联体 它可以在控制的启动和进展中发挥作用 人绒毛膜促性腺激素。 在这个模型中，任何这些规则的改变 正如在老年人中观察到的那样，分子会导致 HCG 异常。 该提案的目的是首先测试假设，即 肝再生过程中 PAI-1 的表达随着增加而改变 年龄;其次，肝脏 PAI-1 表达的改变 是由于 PAI-1 调节机制的年龄依赖性变化所致 由 HGF 和 TGF-β 产生。 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 部分肝切除术。 mRNA 诱导的动力学和位点将是 通过Northern印迹分析和原位杂交测定。 这 将研究 HGF 和 TGF-β 对 PAI-1 基因表达的调节 在年轻和老年大鼠肝细胞的原代培养物中。 监管 通过基因转录和mRNA分析来研究机制 稳定性，以及顺式作用 DNA 序列的鉴定和 涉及反式作用蛋白。 特定 DNA 蛋白质相互作用 鉴定出的结果将与肝脏过程中体内观察到的结果进行比较 再生。 肝脏 PAI-1 合成的年龄依赖性改变可能可能 影响HCG主要调节因子的平衡。 了解 肝再生过程中 PAI-1 的调节机制可能允许 制定肝病管理新策略 年纪大了。