Gattenlöhner Stefan, Waller Christiane, Ertl Georg, Bültmann Burkhard-Dieter, Müller-Hermelink Hans-Konrad, Marx Alexander
Institute of Pathology, University of Würzburg, Josef-Schneiderstrasse 2, 97080 Würzburg, Germany.
Am J Pathol. 2003 Sep;163(3):1081-90. doi: 10.1016/S0002-9440(10)63467-0.
Chronic myocardial ischemia is the leading cause of impaired myocardial contractility and heart failure. To identify differentially expressed genes in human ischemic cardiomyopathy (ICM), we constructed a subtracted cDNA library using specimens of ICM compared to normal human heart. Among 100 randomly sequenced clones, seven sequences represented recently identified candidate genes for differential expression in cardiac hypertrophy. A further clone without a known hypertrophy-association coded for the adhesion molecule NCAM(CD56). RNase protection assay, immunohistochemistry, and Western blotting revealed strong overexpression of NCAM(CD56) in all hearts with ICM (n = 14) compared to normal hearts (n = 8), whereas in congestive cardiomyopathy (CCM) (n = 8), hypertrophic obstructive cardiomyopathy (n = 2), myocarditis (n = 4), and sarcoidosis (n = 2), at most slight overexpression of NCAM(CD56) was observed. NCAM(CD56) overexpression abnormally involved the whole cell membrane and the cytoplasma of cardiomyocytes only inside and adjacent to ischemia-induced cardiac scars. Normal or hypertrophic fibers at a distance from ischemic scars were devoid of NCAM overexpression. Identical alterations were observed in an experimental rat ICM model, but not in normal nor in spontaneously hypertensive rat hearts. In search of NCAM(CD56)-related transcription factors we found RUNX1(AML1) up-regulation in ICM and detected RUNX1(AML1) binding within the NCAM(CD56) promoter by electromobility shift assay. We concluded that strong overexpression of NCAM(CD56) and RUNX1(AML1) is a constant and characteristic feature of cardiomyocytes within or adjacent to scars in ICM.
慢性心肌缺血是心肌收缩力受损和心力衰竭的主要原因。为了鉴定人类缺血性心肌病（ICM）中差异表达的基因，我们使用ICM标本与正常人心标本构建了一个消减cDNA文库。在100个随机测序的克隆中，有7个序列代表了最近鉴定出的在心肌肥厚中差异表达的候选基因。另一个没有已知肥厚相关性的克隆编码黏附分子NCAM（CD56）。核糖核酸酶保护分析、免疫组织化学和蛋白质印迹分析显示，与正常心脏（n = 8）相比，所有ICM心脏（n = 14）中NCAM（CD56）均有强烈的过表达，而在充血性心肌病（CCM）（n = 8）、肥厚性梗阻性心肌病（n = 2）、心肌炎（n = 4）和结节病（n = 2）中，最多仅观察到NCAM（CD56）的轻微过表达。NCAM（CD56）的过表达异常地累及整个细胞膜以及仅在缺血性心脏瘢痕内部和附近的心肌细胞胞质。远离缺血性瘢痕的正常或肥厚纤维未出现NCAM过表达。在实验性大鼠ICM模型中观察到了相同的改变，但在正常大鼠和自发性高血压大鼠心脏中未观察到。在寻找与NCAM（CD56）相关的转录因子时，我们发现ICM中RUNX1（AML1）上调，并通过电泳迁移率变动分析检测到RUNX1（AML1）与NCAM（CD56）启动子内的结合。我们得出结论，NCAM（CD56）和RUNX1（AML1）的强烈过表达是ICM瘢痕内或附近心肌细胞的一个恒定且特征性的特征。
