Annexin-1 peptide Anx-1 _2-26 protects adult rat cardiac myocytes from cellular injury induced by simulated ischaemia

The anti-inflammatory properties of annexin-1 peptides have been largely ascribed to their powerful antineutrophil actions in vivo. We have recently reported that the N-terminal fragment of annexin-1, Anx-1 _2-26, preserves contractile function of cardiac muscle in vitro. The aim of the present study was to determine if Anx-1 _2-26 elicits protective actions specifically on the cardiac myocyte (in the absence of neutrophils), using a model of metabolic inhibition to simulate ischaemia. 2 Metabolic inhibition of cardiac myocytes (4 h incubation at 37°C in HEPES-containing buffer supplemented with 2-deoxy-D-glucose, D,L-lactic acid and pH adjusted to 6.5) followed by 2.5 h recovery in normal medium markedly increased creatine kinase (CK) and lactate dehydrogenase (LDH) levels by 179 ± 39 and 26 ± 7IU L ^-1 (both n = 40, P < 0.001), respectively. However, cellular injury was significantly decreased when Anx-1 _2-26 (0.3 mu;M) was present during metabolic inhibition, CK by 74 ± 10% and LDH by 71 ± 6% (both n = 31, P < 0.001), respectively. 3 Boc 2 (10 μM), a nonselective formyl peptide receptor antagonist, present during metabolic inhibition, abolished the cardioprotective effect of Anx-1 _2-26. 4 Addition of chelerythrine (10 μM), 5-hydroxydecanoate (500 μM) or SB202190 (1 μM) during metabolic inhibition also abolished Anx-1 _2-26- induced cardioprotection. 5 Cellular injury induced by metabolic inhibition was also largely prevented when myocytes were incubated with Anx-1 _2-26 for 5 min with 10 min recovery prior to the insult, or when Anx-1 _2-26 was present only during the recovery period following drug-free metabolic inhibition. 6 In conclusion, the annexin-1 peptide Anx-1 _2-26 potently prevents cardiac myocyte injury induced by metabolic inhibition, an action that was dependent at least in part on the activation of the formyl peptide receptor family of G-protein-coupled receptors, protein kinase C, p38 mitogen-activated protein kinase and ATP-sensitive potassium channels.