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 H 2 O 2 -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. uretic peptide signaling on the size of myocardial infarcts evoked by protocols of ischemia and reperfusion. Methods Animals. GC-A-deficient (GC-A -/-) mice and their GC-A +/+littermates (wild-type controls) were generated as described previously (26). All mice used in this study were between 10 and 14 weeks old. C57BL/6 (10-14 weeks) mice were purchased from Shimizu Co. (Kyoto, Japan). All experimental procedures were performed according to Kyoto University standards for animal care.Surgical procedures. Mice were initially anesthetized with ether and placed on a warm pad maintained at 37°C. The trachea of each mouse was cannulated with a polyethylene tube connected to a respirator (Shinano Co., Tokyo, Japan) with a tidal volume set at 0.6 ml and a rate set at 110/min. The mice were then anesthetized with 0.5-1.5% isoflurane for the remainder of the surgical procedure. After a 10-minute equilibration period, a left thoracotomy was performed between the fourth and fifth ribs. The pericardial sac was then removed, and the left anterior descending artery (LAD) was visualized under a microscope and ligated with a 7-0 silk suture using a snare occluder. To avoid injuring the LAD, a small patch was attached to its surface. Ischemia and reperfusion were accomplished by first tightening the snare occluder and then loosening it. Significant electrocardiogram and color changes at the area at risk (AAR) were considered indicative of successful coronary occlusion and reperfusion. The silk suture was left in place, and chests of the mice were closed with 5-0 silk sutures. The animals were then weaned from the respirator, and the intratracheal tube was removed once they were breathing spontaneously and began to move.Myo...

Disruption of Guanylyl Cyclase-G Protects against Acute Renal Injury

“…Our findings are in line with those from recent studies showing that ANP induced apoptosis in cultured cardiac myocytes and endothelial cells via GC-A-mediated elevation of cGMP, 32,33 and inhibition/ blockade of GC-A by GC-A Ϫ/Ϫ mice or a nonpeptide GC-A antagonist alleviated myocardial I/R injury through suppression of NF-B-mediated P-selectin induction. 34 Proinflammatory cytokine IL-6 was previously found to be produced by macrophages infiltrating adjacent to ischemic vascular bundles of the outer medulla. 22,23 A local increase in IL-6 was shown to promote PMN accumulation within the ischemic renal tissue by directly amplifying a substantial production of the proinflammatory cytokines IL-1␤ and TNF-␣ and/or an upregulation of the adhesion molecules intercellular adhesion molecule-1 and P-selectin on the endothelium.…”

Mechanism of acute pancreatitis complicated with injury of intestinal mucosa barrier

“…After activation, nucleus translocation of NF-κB will occur. NF-κB will bind the κB site on promoter or enhancer of target genes to promote or enhance the expressions of corresponding cytokines in cell nucleus, adhesion molecules and chemotactic factors (Izumi et al, 2001;Antonelli et al, 2001;Ginis et al, 2002;Wright et al, 2002;Lakshminarayanan et al, 2001;Moine et al, 2000;Valen et al, 2001;Omoya et al, 2001), and to regulate inflammation and immunological reactions (Neurath et al, 1998). Although the massive production of inflammatory mediators in local intestinal tract is a defense reaction to the invasion of intestinal bacteria and toxin, it will cause injury of intestinal mucosa (Wang et al, 2002;Theuer et al, 2002).…”

Natriuretic Peptide Receptor A as a Novel Anticancer Target

“…However, little is known about the effects of NPRA signaling on inflammation and cancer progression. In addition, metastatic melanoma cells produce higher levels of cGMP in response to natriuretic peptides than other cell types, and ANP may contribute to local inflammation in the origin of metastatic melanoma (17). ANP possesses some topological similarity with melanin-concentrating hormone (12).…”