Overexpression of calpastatin by gene transfer prevents troponin I degradation and ameliorates contractile dysfunction in rat hearts subjected to ischemia/reperfusion

Atsuo Maekawa, Jong Kook Lee, Takashi Nagaya, Kaichiro Kamiya, Kenji Yasui, Mitsuru Horiba, Keiko Miwa, Mahmud Uzzaman, Masatoshi Maki, Yuichi Ueda, Itsuo Kodama

Research output: Contribution to journalArticlepeer-review

42 Citations (Scopus)

Abstract

Calpain is a Ca2+-activated neutral protease that supposedly plays a key role in myocardial dysfunction following ischemia/reperfusion, by degrading certain proteins involved in the contraction mechanism. It is possible that overexpression of calpastatin, an endogenous calpain inhibitor, lessens contractile dysfunction in the heart after reperfusion by preventing cardiac troponin I (TnI) degradation. This claim is tested by overexpression of human calpastatin (hCS) in rat hearts ex vivo using an adenovirus vector; the hearts were transplanted heterotopically into the abdomens of recipient rats to allow expression of hCS. On the fourth day after surgery, the hearts were excised and perfused in vitro to study their recovery from 30 min of global ischemia, which was followed by 60 min of reperfusion. The peak recovery of the left ventricular developed pressure (LVDP), and the values of its first derivative (max dP/dt, min dP/dt) in the hCS-overexpressed hearts were 88.9 ± 4.8%, 90.8 ± 9.2% and 106.4 ± 9.8%, respectively; these values were all significantly greater than in the control hearts transfected with LacZ alone (51.4 ± 6.9%, 52.6 ± 8.1% and 54.7 ± 6.6%, P < 0.05). In western blot analysis of ventricular myocardial samples (at 60-min reperfusion) using a monoclonal anti-TnI antibody, two bands corresponding to intact TnI (30 kDa) and TnI fragments (27 kDa) were distinguished. The fraction of 27-kDa TnI (percent of total TnI immunoreactivity) in hCS-overexpressed hearts was significantly less than the controls (5.7 ± 2.7% vs. 18.1 ± 3.2%, P < 0.05), implying a protective action of hCS against TnI degradation. These results suggest that adenovirus-mediated overexpression of hCS in the heart could be a novel biological means to minimize myocardial stunning by ischemia/reperfusion.

Original languageEnglish
Pages (from-to)1277-1284
Number of pages8
JournalJournal of Molecular and Cellular Cardiology
Volume35
Issue number10
DOIs
Publication statusPublished - 01-10-2003
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Cardiology and Cardiovascular Medicine

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