There are multiple lines of evidence showing that oxidative stress and aberrant mitogenic signaling play an important role in the pathogenesis of Alzheimer’s disease (AD). Given the critical role of mitogen-activated protein kinase (MAPK) pathways in regulating cellular processes that are affected in AD, the importance of MAPKs in disease pathogenesis is being increasingly recognized. All MAPK pathways, i.e., the extracellular signal-regulated kinase (ERK) and p38 pathways, are activated in vulnerable neurons in patients with AD suggesting that MAPK pathways are involved in the pathophysiology and pathogenesis of AD. In order to investigate the possibility that oxidative stress may activate ERK1/2 and/or p38MAPK pathways, we examined their activation in human neuroblastoma cells exposed to lipid peroxidation product 4-hydroxynonenal (HNE). Addition of the HNE to the medium did not induce cell toxicity, evaluated by water soluble tetrazolium salt-based assay. The protein phosphorylation levels were examined by immunoblot analysis with specific activity-dependent phosphoantibodies. ERK2 phosphorylation occurs in a time-dependent fashion, maximum activation being achieved within 3 hours after treatment with HNE; we didn’t observed changes of p38MAPK phosphorylation state. In order to investigate the possibility that activation of ERK might account for defence to oxidative stress , we examined its activation and the phosphorylation of the down-stream effector glycogen synthase kinase 3- beta (GSK3-beta). Pre-treatment of cells with U0126 (a selective inhibitor of MEK1/2, the up-stream kinases responsible for ERK1/2 phosphorylation) completely inhibited Ser9-GSK3-beta phosphorylation due to ERK2 activation. This study provide evidence for the important stress response pathway leading to activation of ERK2 and the phosphorylation of Ser9-GSK3-beta. Taken together, our findings indicate that MAPK pathways are differentially activated during the course of HNE response in viable human neuroblastoma cells. We suggest that regulation of ERK2 pathway may be a central facet to any potential treatment for the early stages of AD. Supported by: RFO-University of Bologna.
Dozza B., Zaccheo D., Tabaton M., Strocchi P. (2004). KINASE DEREGULATION BY OXIDATIVE STRESS: RELEVANCE TO ALZHEIMER’S DISEASE. s.l : s.n.
KINASE DEREGULATION BY OXIDATIVE STRESS: RELEVANCE TO ALZHEIMER’S DISEASE
DOZZA, BARBARA;STROCCHI, PAOLA
2004
Abstract
There are multiple lines of evidence showing that oxidative stress and aberrant mitogenic signaling play an important role in the pathogenesis of Alzheimer’s disease (AD). Given the critical role of mitogen-activated protein kinase (MAPK) pathways in regulating cellular processes that are affected in AD, the importance of MAPKs in disease pathogenesis is being increasingly recognized. All MAPK pathways, i.e., the extracellular signal-regulated kinase (ERK) and p38 pathways, are activated in vulnerable neurons in patients with AD suggesting that MAPK pathways are involved in the pathophysiology and pathogenesis of AD. In order to investigate the possibility that oxidative stress may activate ERK1/2 and/or p38MAPK pathways, we examined their activation in human neuroblastoma cells exposed to lipid peroxidation product 4-hydroxynonenal (HNE). Addition of the HNE to the medium did not induce cell toxicity, evaluated by water soluble tetrazolium salt-based assay. The protein phosphorylation levels were examined by immunoblot analysis with specific activity-dependent phosphoantibodies. ERK2 phosphorylation occurs in a time-dependent fashion, maximum activation being achieved within 3 hours after treatment with HNE; we didn’t observed changes of p38MAPK phosphorylation state. In order to investigate the possibility that activation of ERK might account for defence to oxidative stress , we examined its activation and the phosphorylation of the down-stream effector glycogen synthase kinase 3- beta (GSK3-beta). Pre-treatment of cells with U0126 (a selective inhibitor of MEK1/2, the up-stream kinases responsible for ERK1/2 phosphorylation) completely inhibited Ser9-GSK3-beta phosphorylation due to ERK2 activation. This study provide evidence for the important stress response pathway leading to activation of ERK2 and the phosphorylation of Ser9-GSK3-beta. Taken together, our findings indicate that MAPK pathways are differentially activated during the course of HNE response in viable human neuroblastoma cells. We suggest that regulation of ERK2 pathway may be a central facet to any potential treatment for the early stages of AD. Supported by: RFO-University of Bologna.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
