PDPOB Exerts Multiaspect Anti-Ischemic Effects Associated with the Regulation of PI3K/AKT and MAPK Signaling Pathways

The discovery of new therapeutic agents for ischemic stroke remains an urgent need. Here, we identified a novel phenyl carboxylic acid derivative, n-pentyl 4-(3,4-dihydroxyphenyl)-4-oxobutanoate (PDPOB), with anti-ischemic activities. The in vitro anti-ischemic neuroprotective and anti-inflammatory capacities of PDPOB were investigated using neuronal cells suffering from oxygen-glucose deprivation/reperfusion (OGD/R) and microglial cells stimulated by lipopolysaccharide (LPS). PDPOB attenuated the OGD/R-evoked cellular damage of SH-SYSY cells and primary cortical neurons in a concentration-dependent manner. Likewise, PDPOB displayed protective roles against OGD/R-evoked multiaspect neuronal deterioration in SH-SYSY cells, as evidenced by alleviated mitochondrial dysfunction, oxidative stress, and apoptosis. A further study unveiled the accelerated phosphorylation of protein kinase B (AKT) by PDPOB treatment, while blockade of phosphoinositide 3-kinase (PI3K)/AKT signaling substantially diminished the neuroprotective capacities of PDPOB. Additionally, the PDPOB pretreatment dampened the LPS-evoked neuroinflammation in BV2 cells, characterized by the suppressed secretion of nitric oxide (NO) and proinflammatory cytokines, as well as normalized expression of nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Western blotting further revealed that PDPOB abated the overabundant phosphorylation of the extracellular signal-regulated kinase (ERIC), c-Jun-N-terminal kinase (JNK), and p38 in LPS-exposed BV2 cells. The intravenous application of PDPOB (30 mg/kg, single dose) attenuated ipsilateral cerebral infarction in middle cerebral artery occlusion (MCAO) rats, accompanied by recovered neurological behaviors. Collectively, the above observations provided substantial evidence for the favorable properties and mechanistic explanations of PDPOB in the regulation of ischemia-associated neuronal injury and microglial inflammation, which may furnish ideas for the discovery of new therapeutic strategies against cerebral ischemia.