MOLECULAR AND CELLULAR BIOLOGY OF CARDIAC INTERSTITIUM

心脏间质的分子和细胞生物学

• 批准号: 2221100
• 负责人: JAMES W COVELL
• 金额: $ 25.07万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-07-01 至 1995-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2221100
• 关键词: RNase protection assay; aorta obstruction; blood pressure; cell growth regulation; cellular pathology; collagen; crosslink; disease /disorder model; extracellular matrix; fibronectins; gene expression; genetic transcription; heart septum; hypertension; in situ hybridization; laboratory rat; messenger RNA; molecular pathology; northern blottings; protein biosynthesis; swine; ventricular hypertrophy

Muscle fiber shortening and force generation are transduced into the volume and pressure pump function required of the ventricle by the geometric organization of the myocytes and their mechanical coupling. This coupling is accomplished through a highly organized system of interstitial proteins. It is known that this extracellular matrix undergoes adaptive changes in response to alterations in the load on the ventricle, but the mechanisms of this growth are poorly understood. This proposal brings together a group of physiologists, biochemists and molecular biologists to address the role of extracellular proteins in left ventricular hypertrophy. The studies in this proposal are designed to explore the gene expression, maturation, and functional consequences of the adaptive growth of the extracellular matrix in models of acute and gradual onset pressure overload hypertrophy. Four specific questions will be addressed. 1) How do fibronectin and collagen gene expression change in response to acute pressure overload? Northern blot and S1 nuclease protection assays will be used to measure mRNA levels following acute aortic banding in a rat model. In situ hybridization will be utilized to determine the cellular source of these mRNAs. The level of transcription will be evaluated with nuclear runoff assays. Finally, net protein synthesis will be surveyed in isolated hearts perfused with radiolabeled amino acids. 2) In order to identify specific mechanical consequences of pressure overload that may function as stimuli to growth of the extracellular matrix, we will determine which alterations in myocardial finite deformation or estimated wall stress correlate with the changes in mRNA levels for fibronectin and collagen. For these experiments we will apply both methods described above and the techniques of three dimensional strain analysis developed in our laboratory in an a large animal (pig) model. 3) We will examine how changes in the amount, concentration, and extent of crosslinking of collagen alter the residual strain, the diastolic pressure-strain relationship, and the systolic fiber and cross-fiber strains of the myocardium. 4) Finally, we will examine how the gene expression and functional consequences of gradual onset pressure overload differ from those of acute load imposition, using aortic banding in weaning pigs. The results of these studies will increase our understanding of the factors altering cardiac performance in hypertrophy.

肌纤维缩短和力量产生被转化为体积 和压力泵功能所需的心室几何 肌细胞的组织及其机械耦合。 这个联轴器 是通过高度组织的间质蛋白系统完成的。 众所周知，这种细胞外基质会发生适应性变化 对心室负荷变化的反应，但其机制 人们对这种增长知之甚少。 该提案聚集了一个小组 生理学家、生物化学家和分子生物学家来解决这一问题 左心室肥厚中细胞外蛋白的变化。 研究在 该提案旨在探索基因表达、成熟和 细胞外基质适应性生长的功能后果 在急性和逐渐发生的压力超负荷肥大模型中。 四 将解决具体问题。 1) 纤连蛋白和胶原蛋白如何作用 急性压力超负荷时基因表达发生变化？ 北方 印迹和 S1 核酸酶保护测定将用于测量 mRNA 水平 在大鼠模型中进行急性主动脉结扎后。 原位杂交将 用于确定这些 mRNA 的细胞来源。 水平 转录将通过核径流测定进行评估。 最后，网 将在离体心脏中对蛋白质合成进行调查 放射性标记的氨基酸。 2）为了识别特定的机械 压力超负荷的后果可能会刺激生长 细胞外基质，我们将确定心肌的哪些变化 有限变形或估计的壁应力与变化相关 纤连蛋白和胶原蛋白的 mRNA 水平。 对于这些实验，我们将 应用上述两种方法和三维技术 我们实验室对大型动物（猪）进行菌株分析 模型。 3) 我们将研究数量、浓度和 胶原蛋白交联的程度改变残余应变、舒张压 压力-应变关系，以及收缩纤维和交叉纤维 心肌应变。 4）最后，我们将检查基因如何 逐渐发生的压力超负荷的表达和功能后果 与急性负荷施加不同，在脱机中使用主动脉束带 猪。 这些研究的结果将加深我们对 改变肥厚心脏性能的因素。