- Email: [email protected]
pitslre protein kinase is differentially expressed in hippocampus of Alzheimer patients
Poster Presentations P2 simultaneous elevation of I2PP-2A, p53 and Akt was also observed in AD brain and the tg-2576 transgenic mice, suggesting an intrinsic link of I2PP2A with p53 and Akt in AD. Further studies showed that I2PP-2A protein could bind to the promoter regions of p53 and Akt and thus increase the transcription activity. Overexpression of I2PP-2A could activate p53 through stimulating p38 MAPK but not Cdk5; however, the I2PP-2A-induced activation of p53 did not induce cell apoptosis for I2PP-2A also activated Akt. Inhibition of Akt while overexpressing I2PP-2A caused more severe apoptosis than that with Akt inhibition only. Knockdown p53 remarkably restored the decreased cell viability induced by simultaneous Akt inhibition and I2PP-2A overexpression. Conclusions: These data suggest that I2PP-2A can upregulate p53 and Akt by regulating the transcription activity and/or the p38 MAPK pathway. In addition, simultaneous activation of Akt counteracts the activated p53-induce apoptosis. Consistent with our recent report (Li et al., PNAS, 2007; 104: 3591-6), our findings uncover a new mechanism explaining why neurons in AD brain do not die preferentially of apoptosis even though exposed to a proapoptotic environment. P2-170
ACTIVATED PKR LEVELS CORRELATES WITH PACT LEVELS IN THE BRAINS OF AD PATIENTS AND IN APP/PS1 KI TRANSGENIC MICE
Claire Paquet1,2, Franc¸ois Mouton Liger3,2, Constantin Bouras4, Marc Vigny5, Franc¸oise Gray6, Jacques Hugon1,2, 1Memory Center, Lariboisie`re Hospital, PARIS, France; 2Institut du Fer a Moulin Inserm U839, Paris, France; 3Department of Histology, Lariboisie`re Hospital, PARIS, France; 4Department of Neuropsychiatry University of Geneva, GENEVA, France; 5Institut du Fer a Moulin Inserm U839, PARIS, France; 6Department of Pathology, Lariboisie`re Hospital, PARIS, France. Contact e-mail: [email protected] Background: Alzheimer’s disease (AD) is neuropathologically marked by the accumulation of senile plaques made of Ab peptide, by neurofibrillary tangles with phosphorylated tau protein and synaptic and neuronal losses. The signaling pathways leading to neuronal death are not completely known but could be linked to the neurotoxic properties of the Ab peptide. PKR is mainly a pro-apoptotic kinase that is activated by virus, IFN, TNF a, IL1 and calcium. Neuronal PKR can be also activated in vitro by Ab peptide. We have previously shown that activated and phosphorylated PKR (PKRp) accumulates in degenerating neurons observed in the brains of AD patients as well as in APP/PS1 knock in transgenic mice marked by a widespread neuronal degeneration. PKR activation is associated with dimerization and autophosphorylation of the kinase. During cell stress, one of the main PKR trigger is the protein PACT (PKR activator). Methods: Using confocal microscopy, we show that, in AD brains PKRp and PACT can be co-expressed in degenerating neurons of the hippocampus. In this study, using western blot analysis, we have assessed the levels of PKRp (Thr 451) and PACT in the temporal cortex of AD patients (n¼4) and age-matched controls (n¼4) and in the brains APP/PS1 knock in transgenic mice (N¼6) and littermates (N¼4). Results: Increased levels of PKRp (19.2%) and PACT (63%) were observed in the temporal cortex of AD patients compared to controls as well as in the brains of transgenic mice compared to littermates. The levels of PKRp statistically correlate with the levels of the protein PACT in human brains as well as in mice brains. Conclusions: In conclusion, PKRp can colocalized with its activator PACT in degenerating neurons in AD brains and the levels of PACT could determine the levels the pro-apoptotic forms of PKR. PACT could represent a new molecular target to reduce neurodegeneration in AD brains. P2-171
CDK11/PITSLRE PROTEIN KINASE IS DIFFERENTIALLY EXPRESSED IN HIPPOCAMPUS OF ALZHEIMER PATIENTS
Vladan P. Bajic1, Sandra Siedlak2, Mark A. Smith3, Zorana Milicevic4, Lada Zivkovic5, Biljana Spremo-Potparevic6, 1Galenika pharm, Belgrade, Serbia; 2Department of pathology, Case Western University, Cleavland, OH, USA; 3Department of Pathology, Case Western University, Cleveland, OH, USA; 4Department of Endcrinology and Molecular biology, Vinca Institute, Belgrade, Serbia; 5Department of physiology, Faculty of Pharmacy,
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Belgrade, Serbia; 6Department of Physiology, Faculty of Pharmacy, Belgrade, Serbia. Contact e-mail: [email protected] Background: Cyclin-dependent kinase 11 (CDK11) mRNA produces a 110-kDa protein. throughout the cell cycle and a 58-kDa protein that is specifically translated from an internal ribosome entry site sequence during G2/ M phase of the cell cycle. CDK11p58 is required for sister chromatid cohesion and the completion of mitosis. Severe depletion of CDK11 causes defective chromosome congression, premature centromere division, permanent mitotic arrest and cell death. Objective: Recent findings 1) that cohesin, a chromatid cohesion protein regulator is expressed in differentiated postmitotic neurons and 2) that premature centromere division phenotype is found in Alzheimer disease (AD) lead us to evaluate a hypothesis that CDK 11p58 expression levels may be elevated in AD/versus/age matched controls. Methods: Immunohistochemical analysis was used to evaluate expression patterns of CDK 11 in AD compared to age-matched controls. Results: Imunocytochemical data demonstrated that CDK 11 expression is increased in AD neurons, most striking in cases representing Braak V and VI stage of the disease, compared to neurons of the normal, aged matched controls. Conclusions: This investigation showed that CDK 11 may be implicated in cell cycle re-entry in AD neurons, thus presenting a possible intriguing novel research of the altered G2/M pathway in AD. P2-172
ASTRIN, A SUBSTRATE OF GSK3b IS DIFFERENTIALLY EXPRESSED IN AD COMPARED TO AGE-MATCHED CONTROLS
Vladan P. Bajic1, Biljana Spremo-Potparevic2, Dragan Ilievski3, Lada Zivkovic2, Xiongwei Zhu4, Mark A. Smith4, 1Galenika pharm, Belgrade, Serbia; 2Department of Physiology, Faculty of Pharmacy, Belgrade, Serbia; 3Department of Neurology, Skopje, Macedonia, The Former Yugoslav Republic of; 4Department of Pathology, Case Western University, Cleveland, OH, USA. Contact e-mail: [email protected] Background: Astrin is a non-motor spindle associated protein essential for the cell cycle progression, sister chromatid cohesion, and the completion of mitosis. Glycogen synthase kinase 3b (GSK3b) interacts with and phosphorylates astrin, resulting in targeting astrin to the spindle microtubules and kinetochores. GSK3b is one of the most implicated tau kinases involved in Alzheimer-like tau hyperphosphorylation. The importance of GSK3b-astrin complex in microtubule management led us to evaluate the hypothesis that astrin expression levels may be elevated in AD versus age-matched controls. Methods: Immunohistochemical analysis was used to evaluate expression patterns of astrin in ten AD hippocampus subjects compared to age-matched controls. Results: Immunohistochemical data demonstrated that Astrin expression is increased in AD neurons compared to neurons of the normal, aged matched controls. Conclusions: This investigation showed that astrin may be implicated in GSK3b-mediated AD pathology. P2-173
INTERNALIZATION OF ABETA AMYLOID PEPTIDES IN NEURONAL CELLS DEPENDING OF THEIR SEQUENCE AND THEIR STRUCTURAL ASSEMBLY
Lorena Perrone, Honore´ Mazarguil, Marie-Lise Maddelein, CNRS UMR5089, Toulouse, France. Contact e-mail: [email protected] Background: Alzheimer’s disease (AD) is characterized by the accumulation of amyloid beta (Abeta) peptides in amyloid deposits in the cerebral tissue. Current evidence indicates that intraneuronal accumulation of Abeta is an early pathological biomarker for the onset of AD and may contribute to a cascade of neurodegenerative events. Many reports found strong evidence that intermediates in the aggregation process call ’oligomers’ are the principal pathogenic species that drive neuronal dysfunction rather the large amyloid aggregates. Oligomeric soluble forms of Abeta have toxic properties and are believed to induce synaptic degeneration. Active zones are the sites along nerve terminals where synaptic vesicles dock and undergo exocytosis during synaptic transmission. They are characterized by active endocytosis and exocytosis. There are studies suggesting that cellular membranes play a major role in Abeta oligomerization process.
ACTIVATED PKR LEVELS CORRELATES WITH PACT LEVELS IN THE BRAINS OF AD PATIENTS AND IN APP/PS1 KI TRANSGENIC MICE
Claire Paquet1,2, Franc¸ois Mouton Liger3,2, Constantin Bouras4, Marc Vigny5, Franc¸oise Gray6, Jacques Hugon1,2, 1Memory Center, Lariboisie`re Hospital, PARIS, France; 2Institut du Fer a Moulin Inserm U839, Paris, France; 3Department of Histology, Lariboisie`re Hospital, PARIS, France; 4Department of Neuropsychiatry University of Geneva, GENEVA, France; 5Institut du Fer a Moulin Inserm U839, PARIS, France; 6Department of Pathology, Lariboisie`re Hospital, PARIS, France. Contact e-mail: [email protected] Background: Alzheimer’s disease (AD) is neuropathologically marked by the accumulation of senile plaques made of Ab peptide, by neurofibrillary tangles with phosphorylated tau protein and synaptic and neuronal losses. The signaling pathways leading to neuronal death are not completely known but could be linked to the neurotoxic properties of the Ab peptide. PKR is mainly a pro-apoptotic kinase that is activated by virus, IFN, TNF a, IL1 and calcium. Neuronal PKR can be also activated in vitro by Ab peptide. We have previously shown that activated and phosphorylated PKR (PKRp) accumulates in degenerating neurons observed in the brains of AD patients as well as in APP/PS1 knock in transgenic mice marked by a widespread neuronal degeneration. PKR activation is associated with dimerization and autophosphorylation of the kinase. During cell stress, one of the main PKR trigger is the protein PACT (PKR activator). Methods: Using confocal microscopy, we show that, in AD brains PKRp and PACT can be co-expressed in degenerating neurons of the hippocampus. In this study, using western blot analysis, we have assessed the levels of PKRp (Thr 451) and PACT in the temporal cortex of AD patients (n¼4) and age-matched controls (n¼4) and in the brains APP/PS1 knock in transgenic mice (N¼6) and littermates (N¼4). Results: Increased levels of PKRp (19.2%) and PACT (63%) were observed in the temporal cortex of AD patients compared to controls as well as in the brains of transgenic mice compared to littermates. The levels of PKRp statistically correlate with the levels of the protein PACT in human brains as well as in mice brains. Conclusions: In conclusion, PKRp can colocalized with its activator PACT in degenerating neurons in AD brains and the levels of PACT could determine the levels the pro-apoptotic forms of PKR. PACT could represent a new molecular target to reduce neurodegeneration in AD brains. P2-171
CDK11/PITSLRE PROTEIN KINASE IS DIFFERENTIALLY EXPRESSED IN HIPPOCAMPUS OF ALZHEIMER PATIENTS
Vladan P. Bajic1, Sandra Siedlak2, Mark A. Smith3, Zorana Milicevic4, Lada Zivkovic5, Biljana Spremo-Potparevic6, 1Galenika pharm, Belgrade, Serbia; 2Department of pathology, Case Western University, Cleavland, OH, USA; 3Department of Pathology, Case Western University, Cleveland, OH, USA; 4Department of Endcrinology and Molecular biology, Vinca Institute, Belgrade, Serbia; 5Department of physiology, Faculty of Pharmacy,
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Belgrade, Serbia; 6Department of Physiology, Faculty of Pharmacy, Belgrade, Serbia. Contact e-mail: [email protected] Background: Cyclin-dependent kinase 11 (CDK11) mRNA produces a 110-kDa protein. throughout the cell cycle and a 58-kDa protein that is specifically translated from an internal ribosome entry site sequence during G2/ M phase of the cell cycle. CDK11p58 is required for sister chromatid cohesion and the completion of mitosis. Severe depletion of CDK11 causes defective chromosome congression, premature centromere division, permanent mitotic arrest and cell death. Objective: Recent findings 1) that cohesin, a chromatid cohesion protein regulator is expressed in differentiated postmitotic neurons and 2) that premature centromere division phenotype is found in Alzheimer disease (AD) lead us to evaluate a hypothesis that CDK 11p58 expression levels may be elevated in AD/versus/age matched controls. Methods: Immunohistochemical analysis was used to evaluate expression patterns of CDK 11 in AD compared to age-matched controls. Results: Imunocytochemical data demonstrated that CDK 11 expression is increased in AD neurons, most striking in cases representing Braak V and VI stage of the disease, compared to neurons of the normal, aged matched controls. Conclusions: This investigation showed that CDK 11 may be implicated in cell cycle re-entry in AD neurons, thus presenting a possible intriguing novel research of the altered G2/M pathway in AD. P2-172
ASTRIN, A SUBSTRATE OF GSK3b IS DIFFERENTIALLY EXPRESSED IN AD COMPARED TO AGE-MATCHED CONTROLS
Vladan P. Bajic1, Biljana Spremo-Potparevic2, Dragan Ilievski3, Lada Zivkovic2, Xiongwei Zhu4, Mark A. Smith4, 1Galenika pharm, Belgrade, Serbia; 2Department of Physiology, Faculty of Pharmacy, Belgrade, Serbia; 3Department of Neurology, Skopje, Macedonia, The Former Yugoslav Republic of; 4Department of Pathology, Case Western University, Cleveland, OH, USA. Contact e-mail: [email protected] Background: Astrin is a non-motor spindle associated protein essential for the cell cycle progression, sister chromatid cohesion, and the completion of mitosis. Glycogen synthase kinase 3b (GSK3b) interacts with and phosphorylates astrin, resulting in targeting astrin to the spindle microtubules and kinetochores. GSK3b is one of the most implicated tau kinases involved in Alzheimer-like tau hyperphosphorylation. The importance of GSK3b-astrin complex in microtubule management led us to evaluate the hypothesis that astrin expression levels may be elevated in AD versus age-matched controls. Methods: Immunohistochemical analysis was used to evaluate expression patterns of astrin in ten AD hippocampus subjects compared to age-matched controls. Results: Immunohistochemical data demonstrated that Astrin expression is increased in AD neurons compared to neurons of the normal, aged matched controls. Conclusions: This investigation showed that astrin may be implicated in GSK3b-mediated AD pathology. P2-173
INTERNALIZATION OF ABETA AMYLOID PEPTIDES IN NEURONAL CELLS DEPENDING OF THEIR SEQUENCE AND THEIR STRUCTURAL ASSEMBLY
Lorena Perrone, Honore´ Mazarguil, Marie-Lise Maddelein, CNRS UMR5089, Toulouse, France. Contact e-mail: [email protected] Background: Alzheimer’s disease (AD) is characterized by the accumulation of amyloid beta (Abeta) peptides in amyloid deposits in the cerebral tissue. Current evidence indicates that intraneuronal accumulation of Abeta is an early pathological biomarker for the onset of AD and may contribute to a cascade of neurodegenerative events. Many reports found strong evidence that intermediates in the aggregation process call ’oligomers’ are the principal pathogenic species that drive neuronal dysfunction rather the large amyloid aggregates. Oligomeric soluble forms of Abeta have toxic properties and are believed to induce synaptic degeneration. Active zones are the sites along nerve terminals where synaptic vesicles dock and undergo exocytosis during synaptic transmission. They are characterized by active endocytosis and exocytosis. There are studies suggesting that cellular membranes play a major role in Abeta oligomerization process.