Development of Strategy of Molecular Cloning of Cardiac-Specific-Gene by use of Adriamycin

CARP是一种心脏阿霉素反应蛋白，已被鉴定为在阿霉素作用下表达下调的核蛋白。在本研究中，我们试图研究病理生理应激与CARP基因表达调控之间的联系，以特异性地验证CARP作为一个核因子介导心脏对各种应激的遗传反应的假设。在压力超载肥厚大鼠心肌组织中，CARP表达显著升高。在大鼠发育过程中，CARP表达增加，这与心脏肥厚伴随“胎儿”基因程序重新激活的概念形成鲜明对比。与压力依赖性调节一致，左心室中CARP mRNA的丰度高于右心室。达尔盐敏感大鼠表现出从心肌肥厚到心力衰竭的盐依赖转变，在代偿性心肌肥厚期间，CARP mRNA水平升高，但在明显心力衰竭发生后，CARP mRNA水平的升高减弱。大鼠腹腔注射低剂量的脂多糖（LPS）诱导心脏中鲤鱼的表达，而高剂量的LPS抑制其表达，尽管iNOS mRNA水平同样增加。通过下调Ca-ATPase mRNA来评估，兔慢性静脉注射阿霉素在轻度心力衰竭时增加CARP mRNA水平，而在心力衰竭变得严重时降低其水平。这些结果表明，根据血流动力学过载的程度，CARP的表达受到不同的调节，并且在心脏适应和衰竭过程中，CARP可能在调节基因表达方面发挥作用。

CARP,a cardiac adriamycin response protein, has been identified as a nuclear protein whose expression is down-regulated in response to adriamycin. In this study, we sought to examine the link between the pathophysiological stress and the regulation of CARP gene expression to specifically test the hypothesis that CARP functions as a nuclear factor mediating genetic response to diverse stress in the heart. CARP expression markedly increased in pressure-overloaded hypertrophy of rat heart. CARP expression increased during rat development, which is in a sharp contrast to the concept that cardiac hypertrophy is accompanied by the reactivation of the "fetal" gene program. Consistent with pressure-depenedent regulation, CARP mRNA was present in greater abundance in left ventricle than in right ventricle. In Dahl salt sensitive rats which exhibits the transition from cardiac hypertrophy to heart failure in a salt dependent manner, CARP mRNA increased during the period of compensatoty cardiac hypertrophy but such an increase in CARP mRNA level was attenuated after overt heart failure developed. Intraperitoneal administration of low dose of lipopolysaccharides(LPS) in rats induced CARP expression in the heart whereas higher dose of LPS repressed its expression despite either equally increased the level of iNOS mRNA.Chronic intravenous injection of adriamycin in rabbits increased CARP mRNA levels in mild heart failure while decreased it when heart failure became severe as assessed by the downregulation of Ca-ATPase mRNA.These results suggest taht CARP expression is differentially regulated depending upon the magnitude of hemodynamic overload and CARP may play a role in regulating gene expression during cardiac adaptation and failure.