Blockade of the natriuretic peptide receptor guanylyl cyclase-A inhibits NF-κB activation and alleviates myocardial ischemia/reperfusion injury
Takehiko Izumi, Yoshihiko Saito, Ichiro Kishimoto, Masaki Harada, Koichiro Kuwahara, Ichiro Hamanaka, Nobuki Takahashi, Rika Kawakami, Yuhao Li, Genzo Takemura, Hisayoshi Fujiwara, David L. Garbers, Seibu Mochizuki, Kazuwa Nakao
Takehiko Izumi, Yoshihiko Saito, Ichiro Kishimoto, Masaki Harada, Koichiro Kuwahara, Ichiro Hamanaka, Nobuki Takahashi, Rika Kawakami, Yuhao Li, Genzo Takemura, Hisayoshi Fujiwara, David L. Garbers, Seibu Mochizuki, Kazuwa Nakao
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Article

Blockade of the natriuretic peptide receptor guanylyl cyclase-A inhibits NF-κB activation and alleviates myocardial ischemia/reperfusion injury

Abstract

Acute myocardial infarction (AMI) remains the leading cause of death in developed countries. Although reperfusion of coronary arteries reduces mortality, it is associated with tissue injury. Endothelial P-selectin–mediated infiltration of neutrophils plays a key role in reperfusion injury. However, the mechanism of the P-selectin induction is not known. Here we show that infarct size after ischemia/reperfusion was significantly smaller in mice lacking guanylyl cyclase-A (GC-A), a natriuretic peptide receptor. The decrease was accompanied by decreases in neutrophil infiltration in coronary endothelial P-selectin expression. Pretreatment with HS-142-1, a GC-A antagonist, also decreased infarct size and P-selectin induction in wild-type mice. In cultured endothelial cells, activation of GC-A augmented H2O2-induced P-selectin expression. Furthermore, ischemia/reperfusion–induced activation of NF-κB, a transcription factor that is known to promote P-selectin expression, is suppressed in GC-A–deficient mice. These results suggest that inhibition of GC-A alleviates ischemia/reperfusion injury through suppression of NF-κB–mediated P-selectin induction. This novel, GC-A–mediated mechanism of ischemia/reperfusion injury may provide the basis for applying GC-A blockade in the clinical treatment of reperfusion injury.

Authors

Takehiko Izumi, Yoshihiko Saito, Ichiro Kishimoto, Masaki Harada, Koichiro Kuwahara, Ichiro Hamanaka, Nobuki Takahashi, Rika Kawakami, Yuhao Li, Genzo Takemura, Hisayoshi Fujiwara, David L. Garbers, Seibu Mochizuki, Kazuwa Nakao

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NF-κB binding to DNA during myocardial ischemia/reperfusion in GC-A+/+ a...
NF-κB binding to DNA during myocardial ischemia/reperfusion in GC-A+/+ and GC-A–/– mice. (a) The identity of the band obtained from a NF-κB gel shift assay was confirmed by competition and supershift analyses using a specific anti-p50 subunit Ab as a probe. An arrow in left side shows shifted band. An arrow with broken line shows supershifted band. (b) EMSA of NF-κB in GC-A+/+ (lanes 1, 3, and 5) and GC-A–/– (lanes 2, 4, and 6) hearts; lanes 1 and 2, sham operated; lanes 3 and 4, 30 minutes of ischemia and 6 hours of reperfusion; lanes 5 and 6, 30 minutes of ischemia and 2 days of reperfusion. (c) Semiquantitative analysis of the binding of activated NF-κB to DNA in GC-A+/+ (open bars) and GC-A–/– mice (filled bars). (d and e) Western blot analysis showing phosphorylated IκBα (d) and total IκBα protein expression (e) in left ventricles of GC-A+/+ (lanes 1, 3, and 5) and GC-A–/– (lanes 2, 4, and 6) mice after 30 minutes of ischemia and 6 hours (lanes 3 and 4) or 2 days (lanes 5 and 6) of reperfusion. Lanes 1 and 2 show phosphorylated IκBα (d) and total IκBα protein expression (e) without ischemia/reperfusion. (f and g) Semiquantitative analysis of phosphorylated IκBα (f) and total IκBα (g) protein expression. Phosphorylated IκBα was significantly lower in GC-A–/– mice (filled bars) than in GC-A+/+ mice (open bars) after 6 hours of reperfusion (f). *P < 0.01 vs. 6 hours of reperfusion in GC-A+/+ mice.