title: MAP kinase signaling cascade dysfunction specific to Alzheimer's disease in fibroblasts.
abstract: Mitogen-activated protein kinases (such as Erk1/2) regulate phosphorylation of the microtubule-associated protein tau and processing of the amyloid protein beta, both events critical to the pathophysiology of Alzheimer's disease (AD). Here we report that enhanced and prolonged Erk1/2 phosphorylation in response to bradykinin (BK) was detected in fibroblasts of both familial and sporadic AD, but not age-matched controls (AC). The AD-associated abnormality in Erk1/2 phosphorylation was not seen in fibroblasts from Huntington's disease patients with dementia. The elevation of Erk1/2 phosphorylation occurred immediately after BK stimulation and required an IP3-sensitive Ca(2+) release as well as activation of PKC and c-src as upstream events. Treatment of cells with the PI-3 kinase blocker LY924002 partially inhibited the BK-stimulated Erk1/2 phosphorylation in AC, but had no effect in AD cells, suggesting that the BK-induced Erk1/2 phosphorylation in AD cells is independent of PI-3 kinase. Activation of the cAMP-responsive element binding protein (CREB) monitored as an increase in phosphorylation at Ser-133 was also observed after BK stimulation. Unlike the AD-specific differences for Erk1/2, however, the BK-stimulated CREB phosphorylation was not different between AC and AD cells. Abnormal Erk1/2 activities may alter downstream cellular processes such as gene transcription, amyloid precursor protein processing, and tau protein phosphorylation, which contribute to the pathogenesis of AD. Moreover, detection of AD-specific differences in MAP kinase in peripheral tissues may provide an efficient means for early diagnosis of AD as well as help us to identify therapeutic targets for drug discovery.
authors.affiliation: Laboratory of Adaptive Systems, National Institute of Neurological Disorder and Stroke, National Institutes of Health, Bethesda, Maryland 20892, USA. zhaow@brni-jhu.org
authors.forename: Wei-Qin
authors.initials: WQ
authors.lastname: Zhao
authors.forename: Lakshmi
authors.initials: L
authors.lastname: Ravindranath
authors.forename: Ali S
authors.initials: AS
authors.lastname: Mohamed
authors.forename: Ofer
authors.initials: O
authors.lastname: Zohar
authors.forename: Gina H
authors.initials: GH
authors.lastname: Chen
authors.forename: Constantine G
authors.initials: CG
authors.lastname: Lyketsos
authors.forename: René
authors.initials: R
authors.lastname: Etcheberrigaray
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Alkon
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000378:metabolism*; D001920:Bradykinin / Q000494:pharmacology; D015220:Calcium Channels / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000378:metabolism*; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D053496:Inositol 1,4,5-Trisphosphate Receptors; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D008301:Maleimides / Q000494:pharmacology; D008875:Middle Aged; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000378:metabolism; D043782:Receptor, Bradykinin B2; D018002:Receptors, Bradykinin / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism
chemical_list: D015220:Calcium Channels; D017362:Cyclic AMP Response Element-Binding Protein; D004791:Enzyme Inhibitors; C506926:ITPR1 protein, human; D007211:Indoles; D053496:Inositol 1,4,5-Trisphosphate Receptors; D008301:Maleimides; D043782:Receptor, Bradykinin B2; D018002:Receptors, Bradykinin; D018160:Receptors, Cytoplasmic and Nuclear; D019869:Phosphatidylinositol 3-Kinases; D016392:Proto-Oncogene Proteins pp60(c-src); D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; C070515:bisindolylmaleimide I; D001920:Bradykinin