REGULATION OF ANF AND BNP IN CARDIAC HYPERTROPHY

心钠素(ANF)和脑利钠肽(BNP)有 血管降压作用，而在肾脏中，它们有强大的利钠作用 和利尿活性。虽然它们具有相似的生物活性， 每种激素都有不同的特点，最重要的是DNA的不同 参与基因表达的调控序列。在成年人心中， ANF基因在心房肌和心室肌中优先表达 表情不到整个心脏的5%。相比之下，脑室 BNP信使核糖核酸占整个心脏水平的70%以上。ANF和BNP 信使核糖核酸在不同的容量和条件下在脑室增大 压力超负荷，包括高血压和心力衰竭。考虑到 BNP基因主要在脑室表达，而 BNP与ANF在房室不同，必须明确 调节ANF和BNP合成的方式不同。目标是 这项建议的目的是定义转录和转录后 ANF和BNP基因的差异调控机制 2种体外心肌肥厚模型在心肌肥厚过程中的应用 异丙肾上腺素刺激猫心肌细胞搏动 苯肾上腺素或PMA刺激的新生心肌细胞。 具体来说，需要检验的假设是：1)有 ANF和BNP基因转录速率的差异，以及 5‘侧翼序列(FS)中的顺式作用调控元件 BNP基因与ANF基因的特征不同 新生心肌细胞；2)在心脏肥大过程中， ANF和BNP基因涉及不同于 参与正常组织特异性基因表达的那些；3)不同的 反式作用调节蛋白对ANF和BNP基因表达的影响 正常与肥大的心肌细胞；4)BNP mRNA的稳定性是 在正常和肥厚的脑室中调节不同。这些 研究将使用肥大的细胞培养模型，Northern印迹法 M RNA，嵌合启动子-报告基因结构的转染， 酶分析(荧光素酶和β-半乳糖苷酶)，聚合酶链法 聚合酶链式反应(PCR)、DNA-和RNA-蛋白质凝胶位移及体内分析 调节元件(体内注射DNA)。因此，它们将提供一个 详细分析ANF和BNP基因调控的差异及帮助 美国了解每种激素在疾病中的相关性，例如 高血压和肥厚。

Atrial natriuretic factor (ANF) and brain natriuretic peptide (BNP) have vasodepressor effects, while in the kidney they have potent natriuretic and diuretic activity. Although they have similar biological activity, each hormone has distinct features, most importantly differences in DNA regulatory sequences involved in gene expression. In adult hearts, the gene for ANF is preferentially expressed in the atria, and ventricular expression is less than 5% of the whole heart. In contrast, ventricular BNP mRNA represents greater than 70% of whole heart levels. ANF and BNP mRNA are augmented in the ventricle under various conditions of volume and pressure overload, including hypertension and heart failure. Given that the BNP gene is expressed primarily in the ventricles while the ratio of BNP to ANF is different in atria and ventricles there must be clear differences in the way ANF and BNP synthesis are regulated. The objective of this proposal is to define transcriptional and post-transcriptional mechanisms involved in differential regulation of the ANF and BNP genes during cardiac hypertrophy using 2 in vitro models of hypertrophy: adult feline cardiocytes stimulated to beat with isoproterenol and phenylephrine- or PMA-stimulated neonatal ventricular cardiocytes. Specifically, the hypotheses to be tested are that: 1) there are differences in the rates of transcription of the ANF and BNP genes, and cis-acting regulatory elements in the 5' flanking sequences (fS) of the BNP gene are distinct from those characterized for the ANF gene in neonatal cardiocytes; 2) during cardia hypertrophy, re-expression of the ANF and BNP genes involves cis-acting regulatory regions distinct from those involved in normal tissue-specific gene expression; 3) different trans-acting regulatory proteins affect ANF and BNP gene expression in normal vs. hypertrophied cardiac myocytes; and 4) BNP mRNA stability is regulated differently in normal and hypertrophied ventricles. These studies will employ cell culture models of hypertrophy, Northern blot of mRNA, transfection of chimeric promoter-reporter gene constructions, enzyme assays (luciferase and beta-galactosidase), polymerase chain reaction (PCR), DNA- and RNA-protein gel shift, and in vivo analysis of regulator elements (in vivo injection of DNA). Thus they will provide a detailed analysis of differences in ANF and BNP gene regulation and help us understand the relevance of each hormone in disease, such as hypertension and hypertrophy.