Abstract 16427: Annexin-A1 Tripeptide Attenuates Phosphorylation and Nuclear Translocation of NF-kB p65: Cardioprotection in vitro and in vivo
Background: Annexin-A1 (ANXA1) is an endogenous protein with potent anti-inflammatory properties. A novel ANXA1 tripeptide (ANXA1sp) is cardioprotective via resolving myocardial inflammation. Here, we hypothesized that ANXA1sp attenuates phosphorylation and nuclear translocation of NF-kB p65 and produces cardioprotection following myocardial ischemia-reperfusion (IR) in a time- and dose-dependent manner.
Methods: In vitro simulated IR: Adult rat ventricular cardiomyocytes (ARVCs, n=3) were exposed to ANXA1sp (5, 10, 30, and 60 µM) for 1h, subjected to 2h oxygen-glucose deprivation, followed by reoxygenation. In vivo IR: Male Sprague-Dawley rats (n=5) were subjected to 60 min deep hypothermic circulatory arrest at 18°C and randomized to receive vehicle or ANXA1sp (2 mg/kg, iv) 1h before cardiopulmonary bypass and 1h after reperfusion. Efficacy endpoints and mechanisms assessed at 3, 6, and 24h post-reoxygenation (ARVC) and post-reperfusion (rat) include markers of myonecrosis and apoptosis, myocardial inflammation, and leukocyte extravasation.
Results: In a time- and dose-dependent manner, ANXA1sp significantly reduced myocardial IR injury both in cultured cardiomyocytes after simulated IR, and in rats following IR. The observed cardioprotective effect of ANXA1sp was through attenuation of phosphorylation and nuclear translocation of NF-kB p65 (Figure), inhibition of NF-kB activity, and suppression of expression of downstream pro-inflammatory genes (e.g. TNFα, IL-6, and meloperoxidase).
Conclusions: Here, we provide preliminary evidence that phosphorylation and nuclear translocation of NF-kB p65 (ser536), known to contribute to myocardial necrosis and apoptosis following IR, is attenuated in both cultured cardiomyocytes and the hearts of rats treated with ANXA1sp. This is associated with inhibited NF-kB activity, reduced expression of downstream target pro-inflammatory genes, and attenuated myocardial IR injury.
- © 2012 by American Heart Association, Inc.