Activation of glycogen synthase kinase-3 induces Alzheimer-like tau hyperphosphorylation in rat hippocampus slices in culture

Summary.Formation of neurofibrillary tangle from hyperphosphorylated tau is one of the hallmark lesions seen in Alzheimer’s disease (AD) brain, and neuronal deregulation of glycogen synthase kinase-3 (GSK-3) activity plays key role in tau hyperphosphorylation. In the present study, the role of GSK-3 on tau phosphorylation in hippocampus slice culture was examined by incubating the slice with wortmannin (WT), an inhibitor of phosphatidylinositol 3-kinase (PI3K) and GF-109203X (GFX), an inhibitor of protein kinase C (PKC). It was found that treatment of the slices with GFX or WT separately induced tau hyperphosphorylation both at Ser396/Ser404 (PHF-1) and Ser199/Ser202 (Tau-1) sites. The phosphorylation rate of tau at PHF-1 and Tau-1 epitopes was further increased when GFX and WT were used in combination, and at this condition, AD-like tau accumulation was observed. GSK-3 activity was significantly increased with a concurrently decreased level of inactivated form of GSK-3. Lithium chloride (LiCl), a GSK-3 inhibitor, prevented tau from WT- and GFX-induced hyperphosphorylation. It suggests that GSK-3 is regulated through PI3K and PKC pathway, and activation of GSK-3 not only induces hyperphosphorylation of tau but also leads to accumulation of tau in cultured rat brain slice.

[1]  H. Wiśniewski,et al.  Abnormal phosphorylation of the microtubule-associated protein tau (tau) in Alzheimer cytoskeletal pathology. , 1986, Proceedings of the National Academy of Sciences of the United States of America.

[2]  H. Paudel,et al.  14-3-3 Connects Glycogen Synthase Kinase-3β to Tau within a Brain Microtubule-associated Tau Phosphorylation Complex* , 2003, The Journal of Biological Chemistry.

[3]  K. Titani,et al.  Fetal-type phosphorylation of the tau in paired helical filaments. , 1992, Journal of neurochemistry.

[4]  S. Lovestone,et al.  Phosphorylation of tau by glycogen synthase kinase-3β in intact mammalian cells: The effects on the organization and stability of microtubules , 1996, Neuroscience.

[5]  Jian-Zhi Wang,et al.  Alzheimer-like tau phosphorylation induced by wortmannin in vivo and its attenuation by melatonin. , 2002, Acta pharmacologica Sinica.

[6]  René Hen,et al.  Decreased nuclear β‐catenin, tau hyperphosphorylation and neurodegeneration in GSK‐3β conditional transgenic mice , 2001 .

[7]  B. Winblad,et al.  Loss of inositol 1,4,5-trisphosphate receptor sites and decreased PKC levels correlate with staging of Alzheimer's disease neurofibrillary pathology , 1998, Brain Research.

[8]  D. Alkon,et al.  Peripheral markers in testing pathophysiological hypotheses and diagnosing Alzheimer's disease , 1998, FASEB journal : official publication of the Federation of American Societies for Experimental Biology.

[9]  J. Woodgett,et al.  Differential regulation of glycogen synthase kinase-3 beta by protein kinase C isotypes. , 1992, The Journal of biological chemistry.

[10]  P. Greengard,et al.  Protein phosphorylation inhibits production of Alzheimer amyloid beta/A4 peptide. , 1993, Proceedings of the National Academy of Sciences of the United States of America.

[11]  T. Kudo,et al.  Inactivation of glycogen synthase kinase‐3 by protein kinase C δ: implications for regulation of τ phosphorylation , 2000 .

[12]  E. Koo,et al.  Protein Kinase C ϵ Suppresses Aβ Production and Promotes Activation of α-Secretase , 2001 .

[13]  F. Checler,et al.  Constitutive and Protein Kinase C‐Regulated Secretory Cleavage of Alzheimer's β‐Amyloid Precursor Protein: Different Control of Early and Late Events by the Proteasome , 1997, Journal of neurochemistry.

[14]  G. Evan,et al.  Suppression of c-Myc-induced apoptosis by Ras signalling through PI(3)K and PKB , 1997, Nature.

[15]  D. Alkon,et al.  Alzheimer's-specific effects of soluble beta-amyloid on protein kinase C-alpha and -gamma degradation in human fibroblasts. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[16]  H. Wiśniewski,et al.  Microtubule-associated protein tau. A component of Alzheimer paired helical filaments. , 1986, The Journal of biological chemistry.

[17]  T. Kudo,et al.  Inactivation of glycogen synthase kinase-3 by protein kinase C delta: implications for regulation of tau phosphorylation. , 2000, FEBS letters.

[18]  E. Kokmen,et al.  The risk of dementia among persons with diabetes mellitus: a population-based cohort study. , 1997 .

[19]  K. Titani,et al.  Fetal‐Type Phosphorylation of the τ in Paired Helical Filaments , 1992 .

[20]  G. Johnson,et al.  Tau protein in normal and Alzheimer's disease brain: an update. , 1999, Journal of Alzheimer's disease : JAD.

[21]  Yaakov Stern,et al.  Effect of oestrogen during menopause on risk and age at onset of Alzheimer's disease , 1996, The Lancet.

[22]  W. Tyler,et al.  Protein Synthesis-dependent and -independent Regulation of Hippocampal Synapses by Brain-derived Neurotrophic Factor* , 2001, The Journal of Biological Chemistry.

[23]  D. Geschwind,et al.  Human Wild-Type Tau Interacts with wingless Pathway Components and Produces Neurofibrillary Pathology in Drosophila , 2002, Neuron.

[24]  H. Paudel,et al.  Glycogen Synthase Kinase-3β Is Complexed with Tau Protein in Brain Microtubules* , 2002, The Journal of Biological Chemistry.

[25]  J. Trojanowski,et al.  A68: a major subunit of paired helical filaments and derivatized forms of normal Tau. , 1991, Science.

[26]  G. Schellenberg,et al.  Cerebrospinal fluid and plasma insulin levels in Alzheimer's disease , 1998, Neurology.

[27]  H. Wiśniewski,et al.  Abnormal phosphorylation of the microtubule-associated protein? (tau) in Alzheimer cytoskeletal pathology , 1987 .

[28]  E. Braak,et al.  Distribution, Levels, and Activity of Glycogen Synthase Kinase‐3 in the Alzheimer Disease Brain , 1997, Journal of neuropathology and experimental neurology.

[29]  S. Lovestone,et al.  The phosphorylation of tau: a critical stage in neurodevelopment and neurodegenerative processes. , 1997, Neuroscience.

[30]  R. Jope,et al.  The multifaceted roles of glycogen synthase kinase 3β in cellular signaling , 2001, Progress in Neurobiology.

[31]  E. Koo,et al.  Protein kinase C epsilon suppresses Abeta production and promotes activation of alpha-secretase. , 2001, Biochemical and biophysical research communications.

[32]  Lewis C Cantley,et al.  PI3K: Downstream AKTion Blocks Apoptosis , 1997, Cell.

[33]  Patrick R. Hof,et al.  Tau protein isoforms, phosphorylation and role in neurodegenerative disorders 1 1 These authors contributed equally to this work. , 2000, Brain Research Reviews.

[34]  W. Netzer,et al.  Overactivation of glycogen synthase kinase‐3 by inhibition of phosphoinositol‐3 kinase and protein kinase C leads to hyperphosphorylation of tau and impairment of spatial memory , 2003, Journal of neurochemistry.

[35]  U. Wagner,et al.  Cellular phosphorylation of tau by GSK-3 beta influences tau binding to microtubules and microtubule organisation. , 1996, Journal of cell science.

[36]  N. Cairns,et al.  Tau proteins of alzheimer paired helical filaments: Abnormal phosphorylation of all six brain isoforms , 1992, Neuron.

[37]  M. Mercken,et al.  Glycogen Synthase Kinase-3β Phosphorylates Protein Tau and Rescues the Axonopathy in the Central Nervous System of Human Four-repeat Tau Transgenic Mice* , 2000, The Journal of Biological Chemistry.