Correspondence to Wanli W. Smith: wsmith60{at}jhmi.edu
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Abbreviations used in this paper: Aß, amyloid ß-peptide; AD, Alzheimer's Disease; DCF, 2',7'-dichlorofluorescein; DCFDA, DCF diacetate; DHR, dihydrorhodamine; DIV, day in vitro; FKH, forkhead transcription factor; HE, hydroethidine; MnSOD, manganese superoxide dismutase; NAC, N-acetylcysteine; PP2A1, serine/threonine protein phosphatase 2A1; ROS, reactive oxygen species.
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Introduction |
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A heightened resistance to oxidative stress has been shown to increase longevity in Caenorhabditis elegans and mice (Lin et al., 1997; Migliaccio et al., 1999). Mice lacking the adaptor protein p66Shc live 30% longer than control animals, and cells derived from these mice are resistant to ROS-induced apoptosis (Migliaccio et al., 1999). p66Shc plays an important role in signal transduction from tyrosine kinases to Ras protooncogenes. The three mammalian ShcA isoforms (p46, p52, and p66) share structural features including a COOH-terminal Src homology 2 domain, a proline- and glycine-rich region, a collagen-homologous region 1, and an NH2-terminal phosphotyrosine-binding domain (Pelicci et al., 1992; Luzi et al., 2000). In addition, there is a unique collagen-homologous region 2 domain at the NH2 terminus of the p66Shc isoform containing a serine phosphorylation site (Ser36). It is well established that Shc proteins are phosphorylated at tyrosine residues in response to stimulation by a variety of growth factors and cytokines (Pelicci et al., 1992; Rozakis-Adcock et al., 1992; Cutler et al., 1993; Pronk et al., 1993; Ruff-Jamison et al., 1993). The p46 and p52 isoforms transmit signals from receptor tyrosine kinases to the RasMAPK pathway by forming a stable complex involving Grb2 and a Ras exchange factor, SOS (Son of Sevenless; Pelicci et al., 1992; Egan et al., 1993; Skolnik et al., 1993; Aronheim et al., 1994; Kavanaugh and Williams, 1994; Ohmichi et al., 1994). However, p66Shc appears to be functionally different from the p46 and p52 isoforms. Unlike the other isoforms, p66Shc undergoes phosphorylation mainly at Ser36 after exposure to oxidative stress such as UV light or H2O2 (Kao et al., 1997; Migliaccio et al., 1999; Yang and Horwitz, 2000; Le et al., 2001; Nemoto and Finkel, 2002), although p66Shc is also transiently phosphorylated at tyrosine residues in response to growth factor stimulation (Bonfini et al., 1996; Migliaccio et al., 1997). Phosphorylation at Ser36 is required for conferring increased susceptibility to oxidative stress and is critical for the cell death response elicited by oxidative damage (Skulachev, 2000). Therefore, prevention of this phosphorylation may have a therapeutic impact on diseases that are associated with oxidative damage.
Forkhead transcription factors (FKHs) are a large family of gene products expressed in species ranging from yeast to human, all of which have a domain with sequence similarly to Drosophila forkhead protein. A forkhead subfamily member, DAF-16 in C. elegans, functions in insulin signaling pathways and influences longevity (Lin et al., 1997, 2001; Ogg et al., 1997; Accili and Arden, 2004; Giannakou et al., 2004; Hwangbo et al., 2004). Previous studies have demonstrated that for each of the three DAF-16 vertebrate homologues, FKHR (FOXO1), FKHR-L1 (FOXO3a), and AFX (FOXO4), phosphorylation results in the retention of the protein in the cytosol and, hence, a reduction in forkhead-dependent transcriptional activity (Biggs et al., 1999; Brunet et al., 1999; Kops et al., 1999; Takaishi et al., 1999; Tang et al., 1999; Burgering and Kops, 2002). Subsequent studies have demonstrated the roles of FKHRL1, FKHR, and AFX in the insulin response, the oxidative stress response, and the growth arrest/apoptosis pathways (S. Guo et al., 1999; Medema et al., 2000; Zheng et al., 2002; Brunet et al., 2004). Strikingly, recent papers show that p66Shc regulates intracellular oxidant levels in mammalian cells and that ROS can negatively regulate forkhead activity (Nemoto and Finkel, 2002; Trinei et al., 2002). In contrast, activation of FKHs leads to transcriptional activation of the manganese superoxide dismutase (MnSOD) gene and increases MnSOD mRNA and protein levels. Elevated MnSOD levels cause a reduction of ROS and protection against cell death (Nemoto and Finkel, 2002; Trinei et al., 2002). The role of p66Shc and FKHs in Aß-induced oxidative damage in AD is unknown.
In this study, we test the hypothesis that Aß increases intracellular ROS level, activates the p66Shc signaling pathway, and negatively regulates FKH activity. We demonstrate that treatment with Aß causes cell death and p66Shc phosphorylation at Ser36, partially in a JNK-dependent manner. Aß induced the phosphorylation (inactivation) of forkhead FKHRL1 and FKHR transcription factors in established cultures and in mouse primary neuronal cultures. Cells that ectopically expressed p66ShcS36A or were treated with antioxidants were protected against Aß-induced death and exhibited reduced forkhead phosphorylation. These findings lend strong support to the notion that phosphorylation of Shc66 and forkhead protein play important roles in Aß toxicity in AD.
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Results |
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Discussion |
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The accumulation of oxidative cellular damage has been reported in AD and some other age-related and neurodegenerative diseases, such as Parkinson's, Huntington's, and amyotrophic lateral sclerosis (Sharp and Ross, 1996; Smith et al., 1997; Albers and Beal, 2000; Jellinger, 2001). Previous papers show that Aß can directly generate ROS including H2O2 through inherent redox activity, such as that derived from the complexing of Aß with metals (Cu2+ and Zn2+; Huang et al., 1999a,b; Opazo et al., 2002). ROS are freely permeable across tissue boundaries and accumulate intracellularly. However, the molecular mechanisms of Aß leading to oxidative cell death have not been fully elucidated. Recently, several groups have shown that phosphorylation of the p66Shc adaptor protein plays an important role in signaling events leading to cell death in response to oxidative damage (Migliaccio et al., 1999; Le et al., 2001; Nemoto and Finkel, 2002). Here, we show that Aß can induce p66Shc phosphorylation at Ser36 (Fig. 1). Ectopic expression of p66ShcS36A decreased Aß-induced intracellular ROS level and protected against Aß-induced cell death. Moreover, treatment with antioxidants (ebselen or NAC) decreased intracellular ROS level, reduced p66Shc phosphorylation, and protected against Aß-induced cell death (Fig. 7). These findings support the notion that Aß causes neuronal death by mechanisms involving oxidative damage and requiring p66Shc phosphorylation. It has recently been demonstrated that p66Shc-null mouse fibroblasts have enhanced cellular resistance to treatment with oxidants, UV, and H2O2 (Migliaccio et al., 1999). Mice lacking p66Shc are less susceptible to oxidative damage induced by paraquat and have an extended life span (Migliaccio et al., 1999). These findings suggest that phosphorylation of p66Shc at Ser36 is critical for eliciting cell death in response to oxidative stress. Therefore, the prevention of p66Shc phosphorylation may have a therapeutic impact on AD and other age-related diseases that are associated with oxidative damage.
JNK is a stress-activated protein kinase whose function has been associated with the induction of apoptosis by several types of environmental stress and cellular stress (including H2O2) in neuronal cells (Verheij et al., 1996; Le Niculescu et al., 1999; Namgung and Xia, 2000). Recently, we demonstrated that JNK activation was critical for Aß-induced neuronal death (Wei et al., 2002b). In that paper, overexpression of a dominant-interfering form of SEK1 (MKK4), the upstream kinase of JNK, prevented the cell death induced by Aß and inhibited JNK activation (Wei et al., 2002b). Here, we show that cells expressing SEK1-AL also reduced p66Shc phosphorylation at Ser36, suggesting that JNK activation plays a role in regulating this phosphorylation. We confirmed this possibility by using a chemical inhibitor of JNK, SP600125, which yielded similar results (Fig. 5). Our findings are also in agreement with previous papers showing that JNK is the kinase that phosphorylates p66Shc at Ser36 in response to UV irradiation (Le et al., 2001), although we cannot exclude the possibility that additional kinases may also phosphorylate p66Shc. Several groups have shown that JNK is activated in degenerating or apoptotic neurons in AD brains (Anderson et al., 1995, 1996; Marcus et al., 1998; Shoji et al., 2000; Zhu et al., 2001). Together, these findings suggest that p66Shc, like c-Jun, is a substrate of JNK during the induction neuronal loss in AD by oxidative damage. However, further studies using AD transgenic mice or AD brain tissue are needed to definitively link the JNKp66Shc pathway with AD pathogenesis in vivo.
Genetic determinants of longevity include the forkhead-related transcription factor DAF-16 in C. elegans and the p66SHC locus in mice (Lin et al., 1997; Migliaccio et al., 1999). Previous papers have demonstrated that p66Shc regulates intracellular oxidant levels in mammalian cells and that H2O2 can negatively regulate forkhead activity (Nemoto and Finkel, 2002; Trinei et al., 2002). Expression of FKHRL1 results in an increase in both ROS-scavenging activity and oxidative stress resistance (Nemoto and Finkel, 2002). In agreement with this previous literature, we show here that Aß treatment was capable of inducing the phosphorylation of forkhead FKHRL1 and FKHR transcription factors in cells and primary cultures. Cells expressing p66ShcS36A as well as cells treated with ebselen or NAC exhibited more resistance to Aß-induced death and reduced forkhead phosphorylation. Previous studies have shown that phosphorylation of FKHs results in their cytoplasmic retention and inactivation, thereby inhibiting the expression of FKH-regulated genes, which control the cell cycle, cell death, cell metabolism, and oxidative stress (Brunet et al., 2001; Burgering and Kops, 2002). This pathway appears to be well conserved throughout evolution from C. elegans to higher eukaryotes (Biggs et al., 1999; Brunet et al., 1999; Kops et al., 1999; Tran et al., 2002). Whereas nonphosphorylated FKHs are localized in the nucleus and activate gene transcription, phosphorylation of FKHs induces their relocalization from the nucleus to the cytoplasm (and hence away from the promoters of target genes) and consequently inhibits their ability to induce the expression of target genes such as MnSOD (Biggs et al., 1999; Brunet et al., 1999; Nakamura et al., 2000; Dijkers et al., 2000a, b; Kops et al., 2002; Tran et al., 2002). These FKH regulatory events likely represent one of the mechanisms underlying Aß toxicity. Interestingly, in cells expressing p66ShcS36A, phosphorylation of FKHR was diminished, suggesting that p66Shc phosphorylation may be required for Aß-induced FKH phosphorylation leading to a subsequent down-regulation of target genes such as MnSOD and ensuing cell death. These findings further suggest that p66Shc may function by regulating an intracellular ROS/redox system, which, in turn, modulates forkhead activity. Together with previous papers, we propose that Aß toxicity is elicited through the generation of ROS leading to the activation of the JNK pathway, which in turn activates p66Shc by phosphorylation at Ser36. Activated p66Shc then triggers the phosphorylation of FKH, thereby down-regulating target genes such as MnSOD and leading to an even greater accumulation of cellular ROS. This biochemical cycle causes cell death. In summary, our findings not only advance our understanding of the intricacies of neuronal loss in AD but also suggest that JNK, p66Shc, and FKHs may be useful as potential therapeutic targets in the treatment of AD and other age-related disorders.
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Materials and methods |
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Neuronal cultures
Mouse primary cortical neuronal cultures were derived from a CD-1 outbreed mouse (The Jackson Laboratory) at embryonic 15 to 16. Cortices were dissociated as described previously (Movsesyan et al., 2004); after dissociation, neurons were plated on laminin- and poly-D-lysinecoated plates (BD Biosciences) and cultured in neurobasal medium with the addition of glutamax, B-27 supplement, and penicillin/streptomycin. Under these culture conditions, 95% of cells were neurons. At 7 DIV the neuronal cultures were treated with Aß.
Cell culture and transfection
SH-SY5Y human neuroblastoma cells were grown in DME with 10% FBS, 1x nonessential amino acid, and 1x antibiotic-antimycotic (100 U/ml penicillin, 100 µg/ml streptomycin, and 2.5 µg/ml fungizone) solutions at 37°C in 5% CO2/95% air. Transfections were performed with LipofectAmine (Invitrogen) according to the manufacturer's protocol. SH-SY5Y cells were transfected with either pcDNA3.zeo or pcDNA.zeo-SEK1-AL constructs (provided by J.R. Woodgett, The Princess Margaret Hospital, Toronto, Canada). SEK1-AL encodes a dominant-negative form of SEK1 containing a double mutation (S220A and T224L). Pooled cells stably expressing pcDNA3.zeo or pcDNA.zeo-SEK1-AL were selected in media containing 200 µg/ml Zeocin (Invitrogen) for 2 mo (Wei et al., 2002b). PC12 cells were grown in DME with 10% FCS. Stable PC12 cell lines expressing human wild-type p66Shc and dominant-negative p66Shc were obtained by transfection and subsequent isolation by limiting dilutions in G418 (Nemoto and Finkel, 2002).
Measurement of cell death and viability
Trypan blue exclusion was used to measure cell death by counting the number of dead (blue) and live cells in the cultures after Aß peptide treatment. Hoechst labeling of cells to detect apoptotic nuclei was performed as described previously (Dive et al., 1992; Wei et al., 2002a). In brief, cells were fixed with 4% PFA for 30 min at RT and incubated in a solution containing Hoechst 33342 and propidium iodine for 30 min, after which they were examined by fluorescence microscopy. Apoptotic cells were identified as those exhibiting condensed and fragmented nuclei. The percentage of apoptotic cells was calculated as the ratio of apoptotic cells to total cells. A minimum of 400 cells was counted for each treatment.
SH-SY5Y cell viability assay
Cells were cotransfected with pcDNA3.1-GFP along with vector pcDNA3.1-xpress, pcDNA3.1-xpress-p66Shc, or pcDNA3.1-xpress-p66ShcS36A at a 1:10 ratio for 24 h in 10% FBS DME media, and then changed to 2% FBS DME media and treated with Aß for 24 h. GFP-positive cells were counted by using fluorescence microscopy. A minimum of 1,000 cells were counted in each treatment group. The percentage of GFP-positive cells relative to the total number of cells in six random fields was calculated.
Measurement of cellular caspase-3 activity
Cells were harvested in cell lysis buffer (50 µM Hepes, pH 7.4, 1 mM EDTA, 0.1% CHAPS, and 0.1% Triton X-100). DEVD-p-nitroanilide was the substrate for caspase-3. The experiments were performed according to the manufacturer's protocol (Biosource International).
Measurements of intracellular ROS, superoxide level, and mitochondrial ROS
The levels of cytosolic ROS were measured by DCFDA (Molecular Probes) as previously described (Nemoto and Finkel, 2002; Sponne et al., 2003). In brief, cells were treated with 30 µM Aß 25-35 at 37°C for 4 h, washed with PBS, and incubated for 45 min with DCFDA, which is initially nonfluorescent and is converted by oxidation to the fluorescent molecular DCF. DCF was quantified using a CytoFluor Multi-well Plate Reader (Series 400; PerSeptive Biosystems) with 485-nm excitation and 538-nm emission filters; fluorescence intensity of cells was quantified using confocal microscopy and the METAMORPH image analysis software. The levels of intracellular superoxide anion radical were measured with HE, which is oxidized to fluorescent ethidium cation by superoxide, by using methods similar to those described previously (Q. Guo et al., 1999). In brief, cells were incubated for 30 min in the presence of 5 µM HE (Molecular Probes) and washed twice with Locke's solution, whereupon confocal images of cell-associated ethidium fluorescence were acquired (488-nm excitation and 590-nm emission). The average pixel intensity in individual cell bodies was determined with METAMORPH image analysis software. DHR was used to quantify relative levels of mitochondrial peroxynitrite by using methods similar to those described previously (Q. Guo et al., 1999). DHR localizes to mitochondria and fluoresces when oxidized to the positively charged rhodamine 123 derivative. In brief, cells were incubated for 30 min in the presence of 5 µM DHR and washed three times with Locke's solution, and confocal images of cellular fluorescence were acquired (488-nm excitation and 510-nm emission) and analyzed as described for DCF fluorescence.
Immunoblot and PP2A1 treatment
Cells were harvested in lysis buffer (20 mM Hepes, pH 7.4, 2 mM EGTA, 50 mM ß-glycerophosphate, 1% Triton X-100, 10% glycerol, 1 mM dithiothreitol, 1 mM PMSF, 10 µg/ml leupeptin, 10 µg/ml aprotinin, 1 mM Na3VO4, and 5 mM NaF). Where indicated, cell lysates (0.1 mg of protein) were treated with PP2A1 for 30 min at 30°C as described previously (Yang and Horwitz, 2000). The reaction was stopped by adding sample buffer and boiling. Lysates were resolved on 412% NuPAGE Bis-Tris gels (30 µg/lane) and transferred to polyvinylidene difluoride membranes (Millipore). The membranes were blocked in TBST (10 mM Tris-HCl, pH 7.4, 150 mM NaCl, and 0.1% Tween 20) containing 5% nonfat milk and probed with different antibodies. Proteins were detected by using ECL reagents (NEN Life Science Products).
Data analysis
Quantitative data are expressed as arithmetic means ± SEM based on at least three separate experiments performed in duplicate. The difference between two groups was statistically analyzed by t test or an analysis of variance (one-way ANOVA). A P value <0.05 was considered significant.
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Acknowledgments |
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This research was funded by the Intramural Research Program of the National Institute on Aging, National Institutes of Health.
Submitted: 7 October 2004
Accepted: 7 March 2005
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References |
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---|
Accili, D., and K.C. Arden. 2004. FoxOs at the crossroads of cellular metabolism, differentiation, and transformation. Cell. 117:421426.[CrossRef][Medline]
Albers, D.S., and M.F. Beal. 2000. Mitochondrial dysfunction and oxidative stress in aging and neurodegenerative disease. J. Neural Transm. Suppl. 59:133154.[Medline]
Anderson, A.J., C.J. Pike, and C.W. Cotman. 1995. Differential induction of immediate early gene proteins in cultured neurons by beta-amyloid (A beta): association of c-Jun with A beta-induced apoptosis. J. Neurochem. 65:14871498.[Medline]
Anderson, A.J., J.H. Su, and C.W. Cotman. 1996. DNA damage and apoptosis in Alzheimer's disease: colocalization with c-Jun immunoreactivity, relationship to brain area, and effect of postmortem delay. J. Neurosci. 16:17101719.[Abstract]
Aronheim, A., D. Engelberg, N. Li, N. al Alawi, J. Schlessinger, and M. Karin. 1994. Membrane targeting of the nucleotide exchange factor Sos is sufficient for activating the Ras signaling pathway. Cell. 78:949961.[CrossRef][Medline]
Behl, C., J.B. Davis, R. Lesley, and D. Schubert. 1994. Hydrogen peroxide mediates amyloid beta protein toxicity. Cell. 77:817827.[CrossRef][Medline]
Biggs, W.H., III, J. Meisenhelder, T. Hunter, W.K. Cavenee, and K.C. Arden. 1999. Protein kinase B/Akt-mediated phosphorylation promotes nuclear exclusion of the winged helix transcription factor FKHR1. Proc. Natl. Acad. Sci. USA. 96:74217426.
Bonfini, L., E. Migliaccio, G. Pelicci, L. Lanfrancone, and P.G. Pelicci. 1996. Not all Shc's roads lead to Ras. Trends Biochem. Sci. 21:257261.[CrossRef][Medline]
Brunet, A., A. Bonni, M.J. Zigmond, M.Z. Lin, P. Juo, L.S. Hu, M.J. Anderson, K.C. Arden, J. Blenis, and M.E. Greenberg. 1999. Akt promotes cell survival by phosphorylating and inhibiting a Forkhead transcription factor. Cell. 96:857868.[CrossRef][Medline]
Brunet, A., S.R. Datta, and M.E. Greenberg. 2001. Transcription-dependent and -independent control of neuronal survival by the PI3K-Akt signaling pathway. Curr. Opin. Neurobiol. 11:297305.[CrossRef][Medline]
Brunet, A., L.B. Sweeney, J.F. Sturgill, K.F. Chua, P.L. Greer, Y. Lin, H. Tran, S.E. Ross, R. Mostoslavsky, H.Y. Cohen, et al. 2004. Stress-dependent regulation of FOXO transcription factors by the SIRT1 deacetylase. Science. 303:20112015.
Burgering, B.M., and G.J. Kops. 2002. Cell cycle and death control: long live Forkheads. Trends Biochem. Sci. 27:352360.[CrossRef][Medline]
Butterfield, D.A., and A.I. Bush. 2004. Alzheimer's amyloid beta-peptide (1-42): involvement of methionine residue 35 in the oxidative stress and neurotoxicity properties of this peptide. Neurobiol. Aging. 25:563568.[CrossRef][Medline]
Butterfield, D.A., A. Castegna, C.M. Lauderback, and J. Drake. 2002. Evidence that amyloid beta-peptide-induced lipid peroxidation and its sequelae in Alzheimer's disease brain contribute to neuronal death. Neurobiol. Aging. 23:655664.[CrossRef][Medline]
Cutler, R.L., L. Liu, J.E. Damen, and G. Krystal. 1993. Multiple cytokines induce the tyrosine phosphorylation of Shc and its association with Grb2 in hemopoietic cells. J. Biol. Chem. 268:2146321465.
Dijkers, P.F., R.H. Medema, J.W. Lammers, L. Koenderman, and P.J. Coffer. 2000a. Expression of the pro-apoptotic Bcl-2 family member Bim is regulated by the forkhead transcription factor FKHR-L1. Curr. Biol. 10:12011204.[CrossRef][Medline]
Dijkers, P.F., R.H. Medema, C. Pals, L. Banerji, N.S. Thomas, E.W. Lam, B.M. Burgering, J.A. Raaijmakers, J.W. Lammers, L. Koenderman, and P.J. Coffer. 2000b. Forkhead transcription factor FKHR-L1 modulates cytokine-dependent transcriptional regulation of p27(KIP1). Mol. Cell. Biol. 20:91389148.
Dive, C., C.D. Gregory, D.J. Phipps, D.L. Evans, A.E. Milner, and A.H. Wyllie. 1992. Analysis and discrimination of necrosis and apoptosis (programmed cell death) by multiparameter flow cytometry. Biochim. Biophys. Acta. 1133:275285.[CrossRef][Medline]
Egan, S.E., B.W. Giddings, M.W. Brooks, L. Buday, A.M. Sizeland, and R.A. Weinberg. 1993. Association of Sos Ras exchange protein with Grb2 is implicated in tyrosine kinase signal transduction and transformation. Nature. 363:4551.[CrossRef][Medline]
Giannakou, M.E., M. Goss, M.A. Junger, E. Hafen, S.J. Leevers, and L. Partridge. 2004. Long-lived Drosophila with overexpressed dFOXO in adult fat body. Science. 305:361.
Guo, Q., W. Fu, F.W. Holtsberg, S.M. Steiner, and M.P. Mattson. 1999. Superoxide mediates the cell-death-enhancing action of presenilin-1 mutations. J. Neurosci. Res. 56:457470.[CrossRef][Medline]
Guo, S., G. Rena, S. Cichy, X. He, P. Cohen, and T. Unterman. 1999. Phosphorylation of serine 256 by protein kinase B disrupts transactivation by FKHR and mediates effects of insulin on insulin-like growth factor-binding protein-1 promoter activity through a conserved insulin response sequence. J. Biol. Chem. 274:1718417192.
Huang, X., C.S. Atwood, M.A. Hartshorn, G. Multhaup, L.E. Goldstein, R.C. Scarpa, M.P. Cuajungco, D.N. Gray, J. Lim, R.D. Moir, et al. 1999a. The A beta peptide of Alzheimer's disease directly produces hydrogen peroxide through metal ion reduction. Biochemistry. 38:76097616.[CrossRef][Medline]
Huang, X., M.P. Cuajungco, C.S. Atwood, M.A. Hartshorn, J.D. Tyndall, G.R. Hanson, K.C. Stokes, M. Leopold, G. Multhaup, L.E. Goldstein, et al. 1999b. Cu(II) potentiation of alzheimer abeta neurotoxicity. Correlation with cell-free hydrogen peroxide production and metal reduction. J. Biol. Chem. 274:3711137116.
Huang, X., R.D. Moir, R.E. Tanzi, A.I. Bush, and J.T. Rogers. 2004. Redox-active metals, oxidative stress, and Alzheimer's disease pathology. Ann. NY Acad. Sci. 1012:153163.
Hwangbo, D.S., B. Gersham, M.P. Tu, M. Palmer, and M. Tatar. 2004. Drosophila dFOXO controls lifespan and regulates insulin signalling in brain and fat body. Nature. 429:562566.[CrossRef][Medline]
Iversen, L.L., R.J. Mortishire-Smith, S.J. Pollack, and M.S. Shearman. 1995. The toxicity in vitro of beta-amyloid protein. Biochem. J. 311:116.[Medline]
Jellinger, K.A. 2001. Cell death mechanisms in neurodegeneration. J. Cell. Mol. Med. 5:117.[Medline]
Kao, A.W., S.B. Waters, S. Okada, and J.E. Pessin. 1997. Insulin stimulates the phosphorylation of the 66- and 52-kilodalton Shc isoforms by distinct pathways. Endocrinology. 138:24742480.
Kavanaugh, W.M., and L.T. Williams. 1994. An alternative to SH2 domains for binding tyrosine-phosphorylated proteins. Science. 266:18621865.[Medline]
Kops, G.J., N.D. de Ruiter, A.M. Vries-Smits, D.R. Powell, J.L. Bos, and B.M. Burgering. 1999. Direct control of the Forkhead transcription factor AFX by protein kinase B. Nature. 398:630634.[CrossRef][Medline]
Kops, G.J., R.H. Medema, J. Glassford, M.A. Essers, P.F. Dijkers, P.J. Coffer, E.W. Lam, and B.M. Burgering. 2002. Control of cell cycle exit and entry by protein kinase B-regulated forkhead transcription factors. Mol. Cell. Biol. 22:20252036.
Le Niculescu, H., E. Bonfoco, Y. Kasuya, F.X. Claret, D.R. Green, and M. Karin. 1999. Withdrawal of survival factors results in activation of the JNK pathway in neuronal cells leading to Fas ligand induction and cell death. Mol. Cell. Biol. 19:751763.
Le, S., T.J. Connors, and A.C. Maroney. 2001. c-Jun N-terminal kinase specifically phosphorylates p66ShcA at serine 36 in response to ultraviolet irradiation. J. Biol. Chem. 276:4833248336.
Lin, K., J.B. Dorman, A. Rodan, and C. Kenyon. 1997. daf-16: an HNF-3/forkhead family member that can function to double the life-span of Caenorhabditis elegans. Science. 278:13191322.
Lin, K., H. Hsin, N. Libina, and C. Kenyon. 2001. Regulation of the Caenorhabditis elegans longevity protein DAF-16 by insulin/IGF-1 and germline signaling. Nat. Genet. 28:139145.[CrossRef][Medline]
Luzi, L., S. Confalonieri, P.P. Di Fiore, and P.G. Pelicci. 2000. Evolution of Shc functions from nematode to human. Curr. Opin. Genet. Dev. 10:668674.[CrossRef][Medline]
Marcus, D.L., J.A. Strafaci, D.C. Miller, S. Masia, C.G. Thomas, J. Rosman, S. Hussain, and M.L. Freedman. 1998. Quantitative neuronal c-fos and c-jun expression in Alzheimer's disease. Neurobiol. Aging. 19:393400.[CrossRef][Medline]
Medema, R.H., G.J. Kops, J.L. Bos, and B.M. Burgering. 2000. AFX-like Forkhead transcription factors mediate cell-cycle regulation by Ras and PKB through p27kip1. Nature. 404:782787.[CrossRef][Medline]
Migliaccio, E., S. Mele, A.E. Salcini, G. Pelicci, K.M. Lai, G. Superti-Furga, T. Pawson, P.P. Di Fiore, L. Lanfrancone, and P.G. Pelicci. 1997. Opposite effects of the p52shc/p46shc and p66shc splicing isoforms on the EGF receptor-MAP kinase-fos signalling pathway. EMBO J. 16:706716.
Migliaccio, E., M. Giorgio, S. Mele, G. Pelicci, P. Reboldi, P.P. Pandolfi, L. Lanfrancone, and P.G. Pelicci. 1999. The p66shc adaptor protein controls oxidative stress response and life span in mammals. Nature. 402:309313.[CrossRef][Medline]
Movsesyan, V.A., B.A. Stoica, and A.I. Faden. 2004. MGLuR5 activation reduces beta-amyloid-induced cell death in primary neuronal cultures and attenuates translocation of cytochrome c and apoptosis-inducing factor. J. Neurochem. 89:15281536.[CrossRef][Medline]
Nakamura, N., S. Ramaswamy, F. Vazquez, S. Signoretti, M. Loda, and W.R. Sellers. 2000. Forkhead transcription factors are critical effectors of cell death and cell cycle arrest downstream of PTEN. Mol. Cell. Biol. 20:89698982.
Namgung, U., and Z. Xia. 2000. Arsenite-induced apoptosis in cortical neurons is mediated by c-Jun N-terminal protein kinase 3 and p38 mitogen-activated protein kinase. J. Neurosci. 20:64426451.
Nemoto, S., and T. Finkel. 2002. Redox regulation of forkhead proteins through a p66shc-dependent signaling pathway. Science. 295:24502452.
Ogg, S., S. Paradis, S. Gottlieb, G.I. Patterson, L. Lee, H.A. Tissenbaum, and G. Ruvkun. 1997. The Fork head transcription factor DAF-16 transduces insulin-like metabolic and longevity signals in C. elegans. Nature. 389:994999.[CrossRef][Medline]
Ohmichi, M., K. Matuoka, T. Takenawa, and A.R. Saltiel. 1994. Growth factors differentially stimulate the phosphorylation of Shc proteins and their association with Grb2 in PC-12 pheochromocytoma cells. J. Biol. Chem. 269:11431148.
Opazo, C., X. Huang, R.A. Cherny, R.D. Moir, A.E. Roher, A.R. White, R. Cappai, C.L. Masters, R.E. Tanzi, N.C. Inestrosa, and A.I. Bush. 2002. Metalloenzyme-like activity of Alzheimer's disease beta-amyloid. Cu-dependent catalytic conversion of dopamine, cholesterol, and biological reducing agents to neurotoxic H2O2. J. Biol. Chem. 277:4030240308.
Pelicci, G., L. Lanfrancone, F. Grignani, J. McGlade, F. Cavallo, G. Forni, I. Nicoletti, F. Grignani, T. Pawson, and P.G. Pelicci. 1992. A novel transforming protein (SHC) with an SH2 domain is implicated in mitogenic signal transduction. Cell. 70:93104.[CrossRef][Medline]
Pronk, G.J., J. McGlade, G. Pelicci, T. Pawson, and J.L. Bos. 1993. Insulin-induced phosphorylation of the 46- and 52-kDa Shc proteins. J. Biol. Chem. 268:57485753.
Rozakis-Adcock, M., J. McGlade, G. Mbamalu, G. Pelicci, R. Daly, W. Li, A. Batzer, S. Thomas, J. Brugge, and P.G. Pelicci. 1992. Association of the Shc and Grb2/Sem5 SH2-containing proteins is implicated in activation of the Ras pathway by tyrosine kinases. Nature. 360:689692.[CrossRef][Medline]
Ruff-Jamison, S., J. McGlade, T. Pawson, K. Chen, and S. Cohen. 1993. Epidermal growth factor stimulates the tyrosine phosphorylation of SHC in the mouse. J. Biol. Chem. 268:76107612.
Selkoe, D.J. 2001. Alzheimer's disease: genes, proteins, and therapy. Physiol. Rev. 81:741766.
Sharp, A.H., and C.A. Ross. 1996. Neurobiology of Huntington's disease. Neurobiol. Dis. 3:315.[CrossRef][Medline]
Shoji, M., N. Iwakami, S. Takeuchi, M. Waragai, M. Suzuki, I. Kanazawa, C.F. Lippa, S. Ono, and H. Okazawa. 2000. JNK activation is associated with intracellular beta-amyloid accumulation. Brain Res. Mol. Brain Res. 85:221233.[Medline]
Skolnik, E.Y., A. Batzer, N. Li, C.H. Lee, E. Lowenstein, M. Mohammadi, B. Margolis, and J. Schlessinger. 1993. The function of GRB2 in linking the insulin receptor to Ras signaling pathways. Science. 260:19531955.[Medline]
Skulachev, V.P. 2000. The p66shc protein: a mediator of the programmed death of an organism? IUBMB Life. 49:177180.[CrossRef][Medline]
Smith, M.A., P.L. Richey Harris, L.M. Sayre, J.S. Beckman, and G. Perry. 1997. Widespread peroxynitrite-mediated damage in Alzheimer's disease. J. Neurosci. 17:26532657.
Sponne, I., A. Fifre, B. Drouet, C. Klein, V. Koziel, M. Pincon-Raymond, J.L. Olivier, J. Chambaz, and T. Pillot. 2003. Apoptotic neuronal cell death induced by the non-fibrillar amyloid-beta peptide proceeds through an early reactive oxygen species-dependent cytoskeleton perturbation. J. Biol. Chem. 278:34373445.
Takaishi, H., H. Konishi, H. Matsuzaki, Y. Ono, Y. Shirai, N. Saito, T. Kitamura, W. Ogawa, M. Kasuga, U. Kikkawa, and Y. Nishizuka. 1999. Regulation of nuclear translocation of forkhead transcription factor AFX by protein kinase B. Proc. Natl. Acad. Sci. USA. 96:1183611841.
Tang, E.D., G. Nunez, F.G. Barr, and K.L. Guan. 1999. Negative regulation of the forkhead transcription factor FKHR by Akt. J. Biol. Chem. 274:1674116746.
Tran, H., A. Brunet, J.M. Grenier, S.R. Datta, A.J. Fornace Jr., P.S. DiStefano, L.W. Chiang, and M.E. Greenberg. 2002. DNA repair pathway stimulated by the forkhead transcription factor FOXO3a through the Gadd45 protein. Science. 296:530534.
Trinei, M., M. Giorgio, A. Cicalese, S. Barozzi, A. Ventura, E. Migliaccio, E. Milia, I.M. Padura, V.A. Raker, M. Maccarana, et al. 2002. A p53-p66Shc signalling pathway controls intracellular redox status, levels of oxidation-damaged DNA and oxidative stress-induced apoptosis. Oncogene. 21:38723878.[CrossRef][Medline]
Verheij, M., R. Bose, X.H. Lin, B. Yao, W.D. Jarvis, S. Grant, M.J. Birrer, E. Szabo, L.I. Zon, J.M. Kyriakis, et al. 1996. Requirement for ceramide-initiated SAPK/JNK signalling in stress-induced apoptosis. Nature. 380:7579.[CrossRef][Medline]
Wei, W., D.D. Norton, X. Wang, and J.W. Kusiak. 2002a. Abeta 17-42 in Alzheimer's disease activates JNK and caspase-8 leading to neuronal apoptosis. Brain. 125:20362043.
Wei, W., X. Wang, and J.W. Kusiak. 2002b. Signaling events in amyloid beta-peptide-induced neuronal death and insulin-like growth factor I protection. J. Biol. Chem. 277:1764917656.
Yang, C.P., and S.B. Horwitz. 2000. Taxol mediates serine phosphorylation of the 66-kDa Shc isoform. Cancer Res. 60:51715178.
Zheng, W.H., S. Kar, and R. Quirion. 2002. FKHRL1 and its homologs are new targets of nerve growth factor Trk receptor signaling. J. Neurochem. 80:10491061.[CrossRef][Medline]
Zhu, X., A.K. Raina, C.A. Rottkamp, G. Aliev, G. Perry, H. Boux, and M.A. Smith. 2001. Activation and redistribution of c-Jun N-terminal kinase/stress activated protein kinase in degenerating neurons in Alzheimer's disease. J. Neurochem. 76:435441.[CrossRef][Medline]