Post-Synthetic Procollagen Processing in Load-Induced Left Ventricular Remodeling

负荷诱导左心室重构中的合成后原胶原加工

• 批准号: 7737431
• 负责人: Amy D Bradshaw
• 金额: $ 36.88万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7737431
• 关键词: Adhesives; Anabolism; Binding; Binding Proteins; Binding Sites; Biochemistry; Cardiac; Cardiac Myocytes; Cardiovascular system; Catheterization; Cessation of life; Chronic; Clinical; Collagen; Collagen Fibril; Complementary DNA; Cysteine; Deposition; Development; Diagnosis; Echocardiography; Equilibrium; Extracellular Matrix; Extracellular Space; Fibrillar Collagen; Fibroblasts; Functional disorder; Heart failure; Histology; Hospitalization; Hypertrophy; In Vitro; Incidence; Infection; Integral Membrane Protein; Label; Lead; Left; Left Ventricular Remodeling; Left ventricular structure; Location; Measurement; Measures; Metabolic; Mus; Mutate; Myocardial; Patients; Play; Prevalence; Process; Procollagen; Proline; Property; Proteins; Role; Scanning Transmission Electron Microscopy Procedures; Series; Small Interfering RNA; Staining method; Stains; Structure; Techniques; Testing; Time; Transgenic Mice; Ventricular; Ventricular Remodeling; constriction; crosslink; in vivo; light microscopy; papillary muscle; pressure; research study

After biosynthesis within the fibroblast, a procollagen molecule is secreted into the extracellular space where it must undergo a series of very ordered, time sensitive, and location sensitive sequential post-synthetic processing steps in order to become a mature cross-linked insoluble structural collagen fibril. We hypothesized that one fundamental independent mechanism by which chronic pressure overload (PO) increases myocardial fibrillar collagen content, causes the development of abnormal diastolic function and chronic heart failure is an alteration in post-synthetic procollagen processing. This overall hypothesis will be tested using 2 specific aims. Specific Aim 1: determine whether PO changes the balance between procollagen processing into mature cross-linked collagen fibrils vs. procollagen degradation. Specific Aim 2: determine in vitro, using murine primary cardiac fibroblast culture studies, whether a change in SPARC (Secreted Protein Acidic and Rich in Cysteine) expression or procollagen binding results in an isolated change in procollagen processing and fibrillar collagen deposition. PO will be produced by transverse aortic constriction (TAC) in mice. We will examine LV structure & function with echocardiography & catheterization, myocardial function with isolated papillary muscles studies, collagen content, composition and morphometric structure with histology & biochemistry, and procollagen synthesis, procollagen processing, and fibrillar collagen degradation rates with metabolic 14C and 3H proline labeling techniques. The mechanism by which TAC and SPARC alter post-synthetic procollagen processing will be examined using in vitro primary cardiac fibroblast culture studies. Thus, this project will examine whether alteration in SPARC-dependent procollagen processing is a fundamental mechanism by which PO increases myocardial fibrillar collagen content and causes diastolic dysfunction.

在成纤维细胞内生物合成后，前胶原分子被分泌到 细胞外空间必须经历一系列非常有序的、时间敏感的、 位置敏感的连续后合成处理步骤，以便成为 成熟的交联不溶性结构胶原纤维。我们假设一个 慢性压力超负荷（PO）的基本独立机制 增加心肌纤维胶原含量，导致异常发育 舒张功能和慢性心力衰竭是合成后的改变 前胶原加工。这一总体假设将使用 2 个具体目标进行检验。 具体目标 1：确定 PO 是否改变了前胶原之间的平衡 加工成成熟的交联胶原纤维与原胶原降解。具体的 目标 2：使用小鼠原代心脏成纤维细胞培养研究在体外确定， SPARC（酸性和富含半胱氨酸的分泌蛋白）表达是否发生变化 或原胶原结合导致原胶原加工的孤立变化，并且 纤维状胶原沉积。 PO 将由横主动脉缩窄 (TAC) 产生 在小鼠中。我们将通过超声心动图检查 LV 结构和功能 导管插入术、离体乳头肌研究的心肌功能、胶原蛋白 内容、组成和形态结构与组织学和生物化学，以及 前胶原合成、前胶原加工和纤维状胶原降解率 采用代谢 14C 和 3H 脯氨酸标记技术。 TAC 的机制 和 SPARC 改变后合成前胶原加工将使用体外检查 原代心脏成纤维细胞培养研究。因此，该项目将检查是否 SPARC 依赖性前胶原加工的改变是一个基本机制 其中 PO 增加心肌纤维胶原含量并引起舒张 功能障碍。