Heart-specific overexpression of choline acetyltransferase gene protects murine heart against ischemia through hypoxia-inducible factor-1α-related defense mechanisms.

Yoshihiko Kakinuma, Masayuki Tsuda, Kayo Okazaki, Tsuyoshi Akiyama, Mikihiko Arikawa, Tatsuya Noguchi, Takayuki Sato

Journal of the American Heart Association 2013 Jan 18

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Murine and human ventricular cardiomyocytes rich in acetylcholine (Ach) receptors are poorly innervated by the vagus, compared with whole ventricular innervation by the adrenergic nerve. However, vagal nerve stimulation produces a favorable outcome even in the murine heart, despite relatively low ventricular cholinergic nerve density. Such a mismatch and missing link suggest the existence of a nonneuronal cholinergic system in ventricular myocardium. To examine the role of the nonneuronal cardiac cholinergic system, we generated choline acetyltransferase (ChAT)-expressing cells and heart-specific ChAT transgenic (ChAT-tg) mice. Compared with cardiomyocytes of wild-type (WT) mice, those of the ChAT-tg mice had high levels of ACh and hypoxia-inducible factor (HIF)-1α protein and augmented glucose uptake. These phenotypes were also reproduced by ChAT-overexpressing cells, which utilized oxygen less. Before myocardial infarction (MI), the WT and ChAT-tg mice showed similar hemodynamics; after MI, however, the ChAT-tg mice had better survival than did the WT mice. In the ChAT-tg hearts, accelerated angiogenesis at the ischemic area, and accentuated glucose utilization prevented post-MI remodeling. The ChAT-tg heart was more resistant to ischemia-reperfusion injury than was the WT heart. These results suggest that the activated cardiac ACh-HIF-1α cascade improves survival after MI. We conclude that de novo synthesis of ACh in cardiomyocytes is a pivotal mechanism for self-defense against ischemia.

Citation

Yoshihiko Kakinuma, Masayuki Tsuda, Kayo Okazaki, Tsuyoshi Akiyama, Mikihiko Arikawa, Tatsuya Noguchi, Takayuki Sato. Heart-specific overexpression of choline acetyltransferase gene protects murine heart against ischemia through hypoxia-inducible factor-1α-related defense mechanisms. Journal of the American Heart Association. 2013 Jan 18;2(1):e004887