PDGF suppresses oxidative stress induced Ca²⁺ overload and calpain activation in neurons

Oxidative stress is crucially involved in the pathogenesis of neurological diseases such as stroke and degenerative diseases. We previously demonstrated that platelet-derived growth factors (PDGFs) protected neurons from H ₂O₂-induced oxidative stress and indicated the involvement of PI3K-Akt and MAP kinases as an underlying mechanism. Ca²⁺ overload has been shown to mediate the neurotoxic effects of oxidative stress and excitotoxicity. We examined the effects of PDGFs on H₂O ₂-induced Ca²⁺ overload in primary cultured neurons to further clarify their neuroprotective mechanism. H₂O ₂-induced Ca²⁺ overload in neurons in a dose-dependent manner, while pretreating neurons with PDGF-BB for 24 hours largely suppressed it. In a comparative study, the suppressive effects of PDGF-BB were more potent than those of PDGF-AA. We then evaluated calpain activation, which was induced by Ca²⁺ overload and mediated both apoptotic and nonapoptotic cell death. H₂O₂-induced calpain activation in neurons in a dose-dependent manner. Pretreatment of PDGF-BB completely blocked H ₂O₂-induced calpain activation. To the best of our knowledge, the present study is the first to demonstrate the mechanism underlying the neuroprotective effects of PDGF against oxidative stress via the suppression of Ca²⁺ overload and inactivation of calpain and suggests that PDGF-BB may be a potential therapeutic target of neurological diseases.