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，已被鉴定为一种核蛋白，其表达响应于阿霉素而下调。在这项研究中，我们试图研究病理生理应激和CARP基因表达调控之间的联系，以具体测试的假设，即CARP功能作为一个核因子介导的遗传反应，以不同的压力在心脏。CARP表达在压力负荷性心肌肥厚中明显增加。CARP表达在大鼠发育过程中增加，这与心脏肥大伴随着“胎儿”基因程序的重新激活的概念形成鲜明对比。与压力依赖性调节一致，CARP mRNA在左心室中比在右心室中存在更大的丰度。在Dahl盐敏感大鼠中，CARP mRNA在代偿性心肌肥厚过程中增加，但这种增加在明显心力衰竭发生后减弱。腹腔注射低剂量脂多糖（LPS）可诱导大鼠心脏CARP表达，而高剂量LPS则抑制其表达，但两者均可增加心肌iNOS mRNA水平。这些结果表明，根据血流动力学超负荷的大小，CARP表达受到不同的调节，并且CARP可能在心脏适应和衰竭期间调节基因表达中起作用。

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.