DE PEDIATRIC COBRE: EXTRACELLULAR MATRIX REMODELING IN CARDIOVASCULAR DISEASES

DE PEDIATRIC COBRE：心血管疾病中的细胞外基质重塑

• 批准号: 7382174
• 负责人: Takeshi Tsuda
• 金额: $ 17.96万
• 依托单位: ALFRED I. DU PONT HOSP FOR CHILDREN
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2007-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7382174
• 关键词: DE; PEDIATRIC; COBRE; EXTRACELLULAR; MATRIX

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The underlying mechanism of heart failure is not well understood. Fibulin-2 is an extracellular matrix (ECM) protein that marks epithelial-mesenchymal transformation during embryonic cardiovascular development but is significantly down-regulated in the postnatal life. Fibulin-2 expression is remarkably up-regulated in myocardial wound healing, indicating its possible role in myocardial fibrosis and ventricular remodeling. Our working hypothesis is that Fibulin-2 intermediates upstream signals to induce ventricular remodeling. To test this hypothesis, Fibulin-2 null mutant mice (Fbln2-/-) were generated by gene targeting technique. Fbln2-/- showed no obvious phenotypic abnormalities compared with the wild type (WT) littermates and showed normal life span and fertility. (1) In vivo animal experiments: Both Fbln2-/- and WT were subject to myocardial infarction (MI) to induce heart failure. Hemodynamic, biochemical, and histological studies were performed to assess the biological role of fibulin-2 in ventricular remodeling after myocardial infarction. (2) In vitro newborn rat ventricular myocyte cell culture experiments: Ventricular myocytes are co-cultured with myocardial fibroblasts and are stimulated with angiotensin-II (Ang-II). The effects of Ang-II over changes in ECM, morphology and proliferation of cells are examined. Then the intrinsic fibulin-2 activity is inhibited by the fibulin-2 antibody to examine whether the neutralizations block the effect of Ang-II in ECM and cells. To date we found that the following: (1) Fbln2-/- resulted in better survival rate than WT at 2 weeks after MI (Fbln2-/- 78%, WT 44%). Although both revealed comparable myocardial hypertrophy, diastolic function was significantly well preserved in Fbln2-/-. Systolic function was better in Fbln2-/- than in WT. The degree of fibrosis is substantially decreased in Fbln2-/- myocardium; and (2) Ang-II increased fibulin-2 expression in a dose-responsive manner at 24 and 48 hours. Antibody blocking experiments will follow. In summary, absence of fibulin-2 preserved ventricular compliance despite comparable hypertrophy after MI. Our data suggest that fibulin-2 intermediates Ang-II related pathways in the formation of myocardial fibrosis and ventricular remodeling.

该子项目是利用 NIH/NCRR 资助的中心拨款提供的资源的众多研究子项目之一。子项目和研究者 (PI) 可能已从另一个 NIH 来源获得主要资金，因此可以在其他 CRISP 条目中出现。列出的机构是中心的机构，不一定是研究者的机构。心力衰竭的潜在机制尚不清楚。 Fibulin-2 是一种细胞外基质 (ECM) 蛋白，在胚胎心血管发育过程中标志着上皮间质转化，但在出生后显着下调。 Fibulin-2 表达在心肌伤口愈合过程中显着上调，表明其在心肌纤维化和心室重塑中可能发挥作用。 我们的工作假设是 Fibulin-2 介导上游信号以诱导心室重塑。为了验证这一假设，通过基因打靶技术生成了 Fibulin-2 无效突变小鼠 (Fbln2-/-)。与野生型（WT）同窝小鼠相比，Fbln2-/-没有表现出明显的表型异常，并且表现出正常的寿命和生育能力。 (1)体内动物实验：Fbln2-/-和WT均经心肌梗塞(MI)诱导心力衰竭。进行血流动力学、生化和组织学研究以评估 fibulin-2 在心肌梗死后心室重塑中的生物学作用。 (2)体外新生大鼠心室肌细胞培养实验：心室肌细胞与心肌成纤维细胞共培养，并用血管紧张素-II(Ang-II)刺激。检查了 Ang-II 对细胞 ECM、形态和增殖变化的影响。然后用 fibulin-2 抗体抑制内在的 fibulin-2 活性，以检查中和作用是否阻断 Ang-II 在 ECM 和细胞中的作用。迄今为止，我们发现以下内容：(1) MI 后 2 周时，Fbln2-/- 比 WT 具有更好的生存率（Fbln2-/- 78%，WT 44%）。尽管两者都显示出类似的心肌肥厚，但 Fbln2-/- 的舒张功能明显得到良好保留。 Fbln2-/- 的收缩功能优于 WT。 Fbln2-/-心肌纤维化程度显着降低； (2) Ang-II 在 24 小时和 48 小时以剂量响应方式增加 fibulin-2 表达。随后将进行抗体阻断实验。总之，尽管 MI 后出现相当的肥厚，但 fibulin-2 的缺失保留了心室顺应性。我们的数据表明，fibulin-2 在心肌纤维化和心室重塑的形成中介导 Ang-II 相关通路。