REGULATION OF ANF AND BNP IN CARDIAC HYPERTROPHY

心钠素（ANF）和脑钠肽（BNP）具有 血管降压作用，而在肾脏中，它们具有强效的利钠利尿作用 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征，最重要的是DNA的差异 参与基因表达的调控序列。在成年人的心中， ANF基因优先在心房和心室表达， 表达不到整个心脏的5%。相反，心室 BNP mRNA占整个心脏水平的70%以上。ANF和BNP mRNA在心室中在各种体积条件下增加， 压力超负荷，包括高血压和心力衰竭。鉴于 BNP基因主要在心室中表达， 心钠素与心钠素在心房和心室中的差异必须明确 ANF和BNP合成调节方式的差异。客观 该提案的一个目的是定义转录和转录后 参与ANF和BNP基因差异调节的机制 使用2种体外肥大模型在心脏肥大期间：成人 用异丙肾上腺素刺激猫心肌细胞搏动， 苯肾上腺素或PMA刺激的新生心室心肌细胞。 具体来说，要检验的假设是：1）有 ANF和BNP基因转录速率的差异，以及 顺式作用调节元件在5'侧翼序列（fS）的 BNP基因与ANF基因的特征不同， 新生儿心肌细胞; 2）在心肌肥大期间， ANF和BNP基因涉及与ANF不同的顺式作用调节区， 参与正常组织特异性基因表达的那些; 3）不同的 反式作用调节蛋白影响心钠素和脑钠素基因表达 正常与肥大心肌细胞;和4）BNP mRNA稳定性 在正常和肥大的心室中调节不同。这些 研究将使用肥大的细胞培养模型，肥大的北方印迹， mRNA，嵌合启动子-报告基因构建体的转染， 酶测定（荧光素酶和β-半乳糖苷酶），聚合酶链 反应（PCR）、DNA-和RNA-蛋白质凝胶移位，以及 调节元件（DNA的体内注射）。他们将提供一个 详细分析ANF和BNP基因调控的差异并提供帮助 我们了解每种激素在疾病中的相关性，例如 高血压和肥大。

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.