Identification and validation of selective upregulation of ventricular myosin light chain type 2 mRNA in idiopathic dilated cardiomyopathy.

BACKGROUND AND AIMS: the etiology of idiopathic dilated cardiomyopathy (IDCM) is unknown, methods such as suppression subtractive hybridization (SSH) and DNA microarray technology can help to identify genes which might be involved in the pathogenesis of this disease. METHODS AND RESULTS: we used SSH which compared mRNA populations extracted from the left ventricular tissue of IDCM hearts and from the control tissue to identify sequences which correspond to genes up-regulated in IDCM. We identified ventricular myosin light chain type 2 (MLC2V), skeletal alpha-actin, long-chain-acyl-CoA-synthetase and mRNA for the protein KIAA0465 as differentially up-regulated genes. Expression of MLC2V mRNA was determined by RT-PCR in patients with end-stage heart failure caused by IDCM (n=11) or coronary artery disease (CAD, n=9) who underwent heart transplantation as well as the controls (n=6). MLC2V/GAPDH ratios were 2.95+/-0.32, 0.69+/-0.03 and 0.28+/-0.08 (arbitrary unit) for the IDCM group, the CAD group and controls, respectively (P<0.05). DNA microarray analysis confirmed the finding of MLC2V upregulation in IDCM (3.7- and 1.8-fold increase in MLC2V mRNA). CONCLUSIONS: we have demonstrated that SSH is a useful method to identify differential myocardial upregulation of genes. Upregulation of MLC2V can be judged as a specific IDCM related feature, which might be clinically helpful.