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: 2442293
• 负责人: CAROLYN J BRUZDZINSKI
• 金额: $ 10.34万
• 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/2442293
• 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.

肝代偿性生长（HCG）或肝再生是一个关键的 对肝损伤、疾病或肝切除的生理反应。 的 HCG的能力随着年龄的增长而减少，导致并发症， 患有肝脏疾病或接受肝脏切除术的个体 肝细胞癌的治疗 纤溶酶原激活物抑制 1型（派-1）是一个立即早期基因表达的HCG期间，在两个 一个月的老鼠 血浆PAI-1和血浆PAI-1水平随年龄增长而变化。 这两种纤溶酶原激活剂，但对肝脏派-1基因的研究很少 表达或其表达的年龄相关性变化在HCG。 的 HCG的两种主要介质，肝细胞生长因子（HCG）和 转化生长因子β（TGF-β），可调节派-1基因 在某些细胞系中表达，但对它们的表达一无所知。 在原代肝细胞中调节派-1的能力。 HGF和TGF-β必须 被蛋白水解裂解以激活;纤溶酶原的组分 激活可以完成该激活。 由于派-1是主要的 作为纤溶酶原激活的调节剂，其可用于调节平衡 通过调节成熟HGF和TGF-β的成熟， 这样的 反馈回路将连接包括HGF、TGF-β和派-1的三联体 它可以控制 HCG。 在这个模型中，任何这些规则的改变 分子将导致HCG的畸变，如在老年人中观察到的。 本提案的目的是首先检验假设，即 派-1在肝再生过程中的表达随着肝细胞增殖的增加而改变。 年龄;第二，肝派-1表达的改变 是由于派-1调节机制的年龄依赖性变化 通过HGF和TGF-β。 大鼠肝再生过程中纤溶酶原激活物抑制剂-1基因表达的调节 将通过70%以下的肝脏生长研究来分析老年大鼠 肝部分切除术 mRNA诱导的动力学和位点将是 通过北方印迹分析和原位杂交测定。 的 将研究HGF和TGF-β对派-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 将通过分析基因转录和mRNA来研究其机制。 稳定性，以及顺式作用DNA序列的鉴定， 反式作用蛋白参与。 特异性DNA蛋白质相互作用 将识别的结果与肝脏移植期间在体内观察到的结果进行比较。 再生 肝脏派-1合成的依赖性改变可能 影响HCG主要介质的平衡。 了解 肝脏再生过程中派-1的调节机制可能允许 开发新的策略来管理肝脏疾病， 老了