Ferulic acid prevents the cerebral ischemic injury-induced decreases of astrocytic phosphoprotein PEA-15 and its two phosphorylated forms

Abstract

Ferulic acid protects neuronal cells against focal cerebral ischemic injury through its anti-oxidative and anti-inflammatory effects. Phosphoprotein enriched in astrocytes 15 (PEA-15) is known to modulate various cellular processes including cell proliferation, apoptosis, and survival. This study was investigated whether ferulic acid can regulate the levels of PEA-15 and its two phosphorylated forms (Ser 104 and Ser 116) in a cerebral ischemic injury model and in neuronal cells exposed to glutamate. A middle cerebral artery occlusion (MCAO) was performed to induce focal cerebral ischemic injury. Adult male rats were immediately treated with vehicle or ferulic acid (100mg/kg) at the beginning of the MCAO, and then cerebral cortices were collected 24h after MCAO. The decrease in PEA-15 level after ischemic injury was detected using a proteomic approach. Ferulic acid administration prevented the ischemic injury-induced decrease of PEA-15 level. Moreover, Western blot analysis clearly confirmed that ferulic acid attenuates the ischemic injury-induced decreases in PEA-15, phospho-PEA-15 (Ser 104), and phospho-PEA-15 (Ser 116) levels. Glutamate exposure induced significant reductions in the levels of PEA-15 and the two phospho-PEA-15 (Ser 104 and Ser 116) in cultured hippocampal neuron, while pretreatment with ferulic acid prevented the glutamate toxicity-induced decreases in these proteins levels. The decrease of phospho-PEA-15 protein level indicates that the anti-apoptotic function of PEA-15 was being inhibited. Thus, these results suggest that ferulic acid protects neuronal cells against ischemic injury by maintenance of phospho-PEA-15 protein levels.