HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Seyedhossein Aharinejad Georg Wieselthaler Ernst Wolner Michael Grimm Permission Requests Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Aharinejad, S. Articles by Grimm, M. Search for Related Content PubMed PubMed Citation Articles by Aharinejad, S. Articles by Grimm, M. Related Collections Molecular biology

---

Original Articles: Adult Cardiac

Programmed Cell Death in Idiopathic Dilated Cardiomyopathy is Mediated by Suppression of the Apoptosis Inhibitor Apollon

^a Department of Cardiothoracic Surgery, Center of Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
^b Department for Cardiovascular Research, Center of Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria

Accepted for publication March 25, 2008.

^_* Address correspondence to Dr Aharinejad, Department of Cardiothoracic Surgery, Medical University of Vienna, Waehringer Guertel 18–20, Vienna, A-1090, Austria (Email: seyedhossein.aharinejad{at}meduniwien.ac.at).

Presented at the Forty-fourth Annual Meeting of The Society of Thoracic Surgeons, Fort Lauderdale, FL, Jan 28–30, 2008.

Background: Idiopathic dilated cardiomyopathy (DCM) is characterized by ventricular wall remodeling and an increased frequency of cardiac cell apoptosis. Apollon is a 528kD cell membrane-anchored protein that inhibits apoptosis by ubiquitinylation facilitating the degradation of Smac/Diablo and caspase-9. The present study tested the hypothesis that the Apollon/Smac system may mediate programmed cell death in DCM.

Methods: Apollon and caspase-9 protein expression was assessed in left ventricular biopsies of explanted failing hearts using Western blotting in 36 DCM patients undergoing cardiac transplantation and in 10 controls. Human cardiac cells were transfected with a plasmid containing the human Apollon complementary DNA or control vector and were subsequently stressed by hypoxia. Apollon, Smac/Diablo, and caspase-9 expression were then examined in cell lysates by real-time polymerase chain reaction and a transferase-mediated dUTP nick-end labeling assay was used to determine the apoptotic index.

Results: In DCM myocardial tissue, Apollon messenger (m)RNA and protein expression was down-regulated compared with control hearts (p < 0.001 and p < 0.005, respectively) concomitant with an increase in activated caspase-9 protein levels (p < 0.001). Cell stress resulted in increased apoptosis in cardiac cells in vitro and down-regulation of Apollon mRNA expression compared with control cells (p < 0.001). Transfection increased Apollon mRNA expression in cell lysates (p < 0.001) and completely prevented hypoxia-induced apoptosis associated with reduced expression of Smac/Diablo and activated caspase-9.

Conclusions: These results suggest that Apollon down-regulation plays a role in programmed cell death associated with DCM. Up-regulation of Apollon might therefore represent a novel therapeutic strategy in the treatment of DCM.