- Email: [email protected]
Altered arginine metabolism in the Alzheimer's hippocampus
P346
Monday, July 15, 2013: Poster Presentations: P2
MONDAY, JULY 15, 2013 POSTER PRESENTATIONS: P2 P2-001
MELATONIN SUPPLEMENT ONLY AT SPECIFIC TIMING RESCUES THE PATHOLOGY AND MEMORY DEFICITS IN TG2576 MICE VIA TARGETING GSK-3
Caixia Peng1, Hu Juan2, Jingping Yuan1, 1Central Hospital of Wuhan, Wuhan, China; 2Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. Contact e-mail: [email protected] Background: Alzheimer disease (AD) is the most common age-related neurodegenerative diseases. The current AD therapies are merely palliative and treatments that address the underlying pathologic mechanisms of AD are still lacking. As multiple factors are involved during the chronic progression of neurodegeneration, only targeting stage-specific pathological factor(s) may reach the goal of disease-modifying interventions. Methods: Tg2576 mice were injected intraperitoneally with 10 mg/kg of melatonin or an equal volume of DMSO in 0.9% saline as vehicle control once a day for 4m or 8m, from 4m to 8m, 4m to 12m or 8m to 12m (n¼20 each, half male and half female), respectively. The mice stop treatment at 12-month-old were reared five mice for each group without any further treatment to 21m, and other were killed at 12-month-old. We measured A b production, tau phosphorylation, activity of GSK-3 b, synapse disorder and behavior deficits by Western blotting, silver and immunohistochemical staining, ELISA and Morris water maze test at 12m. We measured the senile plaques, tau phosphorylation and activity of GSK-3 b at 21m. Results: Treatment of tg2576 mice with melatonin from 4m to 8m did not improve the pathology or behavioral performance of the mice. However, remarkable attenuation of tau and b-amyloid (Ab) pathologies with memory improvement were observed when melatonin was supplied from 8m to 12m or 4m to 12m old of the mice, more importantly, the improvements were still significant when the mice were survived to old ages. We also found that the disease stage-specific alteration of glycogen synthase kinase-3b (GSK-3b) but not protein phosphatase-2A, was correlated with the alterations of the pathology and behavior, and the timely targeting of GSK-3b was critical for the efficacy of melatonin. Conclusions: Melatonin treatment only at proper timing could arrest AD by targeting the activated GSK-3 b, which provides primary evidence for the importance and strategy in developing disease-modifying interventions of AD.
P2-002
acid. Cluster analyses revealed that the 10 related neurochemical variables formed distinct groups, which changed differentially as a function of advanced aging or AD. Conclusions: These findings demonstrate dramatically altered arginine metabolism in the hippocampus of AD brains, which supports the prominent role of arginine metabolism in AD pathogenesis. P2-003
FLUX AND METABOLITE PATHWAY MAPPING IN THE AGING AND ALZHEIMER’S DISEASE HIPPOCAMPUS
Clyde Phelix1, Richard LeBaron2, Dawnlee Roberson3, Greg Villareal4, George Perry5, 1University of Texas at San Antonio, San Antonio, Texas, United States; 2The University of Texas at San Antonio, San Antonio, Texas, United States; 3Alphahelix Biometrics, Inc., Boerne, Texas, United States; 4 AL Phahelix Biometrics, Inc., Boerne, Texas, United States; 5Unviersity of Texas at San Antonio, San Antonio, Texas, United States. Contact e-mail: [email protected] Background: We published two studies on biosimulations for cholesterol and metabolic pathways in the hippocampus for aging and progressive Alzheimer’s disease (AD). The objective of this study was to demonstrate the utility of flux and metabolite pathway mapping for visualizing the integrated systems networks. Methods: We simulated the hippocampus by linking genome-wide transcription profiles from aging, age matched controls and incipient, moderate, and severe cases of AD (from NCBI GEO GSE 11882 and 1297) with corresponding reactions in a biosimulation model, i.e., to derive parameters for a deterministic kinetic model, Transcriptome-To-MetabolomeÔ (TTMÔ) Biosimulation. The model simulates 16 core metabolic pathways, using COPASIÒ. This model has 4 compartments, 220 species (metabolites), 295 reactions, and 428 parameters derived from expression levels for 238 genes.Time series simulations were run using ordinary differential equations to generate level values for metabolites and flux values for reactions. Pathway maps were generated with NodeXL to include changes in metabolite levels, reaction fluxes, and gene expression levels for the reactions. Results: NodeXL is freeware that integrates into Microsoft Excel. Nodes were species and edges were reactions from the TTMÔ model. The nodes represented as spheres where
ALTERED ARGININE METABOLISM IN THE ALZHEIMER’S HIPPOCAMPUS
Ping Liu1, Michael Fleete1, Yu Jing1, Nicola Collie1, Maurice Curtis2, Richard Faull2, Wickliffe Abraham1, Hu Zhang3, 1University of Otago, Dunedin, New Zealand; 2University of Auckland, Auckland, New Zealand; 3 University of Otago, Dunedin, New Zealand. Contact e-mail: ping.liu@ otago.ac.nz Background: Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by progressive memory loss and neuropathological hallmarks of senile plaques and neurofibrillary tangles, with aging as a major risk factor. L-arginine is a semi-essential amino acid that can be metabolised to produce a number of bioactive metabolites. Accumulating evidence suggests that arginine metabolism may play a prominent role in AD pathogenesis. Methods: The present study conducted the enzyme assays, western blot, high-performance liquid chromatography and liquid chromatography mass spectroscopy to compare the L-arginine metabolic profiles in the hippocampus, a brain region that is affected early and severely in AD, in normal cases with an average age of 60 or 80 years and in AD cases with an average age of 80 years. Results: There were AD- and age-related reductions in total activity of nitric oxide synthase (NOS) and protein expression of the constitutive forms of NOS, and AD-related increases in arginase activity and arginase II protein expression. The level of L-ornithine was significantly decreased in the AD group only, with no significant differences between groups in L-arginine and L-citrulline. There were also AD- and age-related changes in putrescine, spermine and glutamate, with no changes in agmatine, spermidine and g -aminobutyric
Legend: Spheres are reactants (metabolites) and arrows are reactions. Both color and size of spheres reflect percent difference between groups; Only size of arrows reflects magnitude of percent difference between groups for flux in the direction of the arrow. Label on the arrows is the gene(s) responsible for the reaction and the color indicates percent difference in gene expression level. Green are lowest (negative) percent differences and orange to red are increasing positivity; brown color is no change. The highest increase was 25 hydroxycholesterol at 18%, bottom center. Two spheres are labeled (top left & bottom center) with percent change metabolite level values; cholesterol (bottom center) sphere size and color = 85% for scalar information. Flux changes range from 20 to 100%. The key pathways that make up the complete cholesterol biosynthetic pathway are labeled. *-mevalonate & squalence; **-FFMAS, ***-TMAS.
Monday, July 15, 2013: Poster Presentations: P2
MONDAY, JULY 15, 2013 POSTER PRESENTATIONS: P2 P2-001
MELATONIN SUPPLEMENT ONLY AT SPECIFIC TIMING RESCUES THE PATHOLOGY AND MEMORY DEFICITS IN TG2576 MICE VIA TARGETING GSK-3
Caixia Peng1, Hu Juan2, Jingping Yuan1, 1Central Hospital of Wuhan, Wuhan, China; 2Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. Contact e-mail: [email protected] Background: Alzheimer disease (AD) is the most common age-related neurodegenerative diseases. The current AD therapies are merely palliative and treatments that address the underlying pathologic mechanisms of AD are still lacking. As multiple factors are involved during the chronic progression of neurodegeneration, only targeting stage-specific pathological factor(s) may reach the goal of disease-modifying interventions. Methods: Tg2576 mice were injected intraperitoneally with 10 mg/kg of melatonin or an equal volume of DMSO in 0.9% saline as vehicle control once a day for 4m or 8m, from 4m to 8m, 4m to 12m or 8m to 12m (n¼20 each, half male and half female), respectively. The mice stop treatment at 12-month-old were reared five mice for each group without any further treatment to 21m, and other were killed at 12-month-old. We measured A b production, tau phosphorylation, activity of GSK-3 b, synapse disorder and behavior deficits by Western blotting, silver and immunohistochemical staining, ELISA and Morris water maze test at 12m. We measured the senile plaques, tau phosphorylation and activity of GSK-3 b at 21m. Results: Treatment of tg2576 mice with melatonin from 4m to 8m did not improve the pathology or behavioral performance of the mice. However, remarkable attenuation of tau and b-amyloid (Ab) pathologies with memory improvement were observed when melatonin was supplied from 8m to 12m or 4m to 12m old of the mice, more importantly, the improvements were still significant when the mice were survived to old ages. We also found that the disease stage-specific alteration of glycogen synthase kinase-3b (GSK-3b) but not protein phosphatase-2A, was correlated with the alterations of the pathology and behavior, and the timely targeting of GSK-3b was critical for the efficacy of melatonin. Conclusions: Melatonin treatment only at proper timing could arrest AD by targeting the activated GSK-3 b, which provides primary evidence for the importance and strategy in developing disease-modifying interventions of AD.
P2-002
acid. Cluster analyses revealed that the 10 related neurochemical variables formed distinct groups, which changed differentially as a function of advanced aging or AD. Conclusions: These findings demonstrate dramatically altered arginine metabolism in the hippocampus of AD brains, which supports the prominent role of arginine metabolism in AD pathogenesis. P2-003
FLUX AND METABOLITE PATHWAY MAPPING IN THE AGING AND ALZHEIMER’S DISEASE HIPPOCAMPUS
Clyde Phelix1, Richard LeBaron2, Dawnlee Roberson3, Greg Villareal4, George Perry5, 1University of Texas at San Antonio, San Antonio, Texas, United States; 2The University of Texas at San Antonio, San Antonio, Texas, United States; 3Alphahelix Biometrics, Inc., Boerne, Texas, United States; 4 AL Phahelix Biometrics, Inc., Boerne, Texas, United States; 5Unviersity of Texas at San Antonio, San Antonio, Texas, United States. Contact e-mail: [email protected] Background: We published two studies on biosimulations for cholesterol and metabolic pathways in the hippocampus for aging and progressive Alzheimer’s disease (AD). The objective of this study was to demonstrate the utility of flux and metabolite pathway mapping for visualizing the integrated systems networks. Methods: We simulated the hippocampus by linking genome-wide transcription profiles from aging, age matched controls and incipient, moderate, and severe cases of AD (from NCBI GEO GSE 11882 and 1297) with corresponding reactions in a biosimulation model, i.e., to derive parameters for a deterministic kinetic model, Transcriptome-To-MetabolomeÔ (TTMÔ) Biosimulation. The model simulates 16 core metabolic pathways, using COPASIÒ. This model has 4 compartments, 220 species (metabolites), 295 reactions, and 428 parameters derived from expression levels for 238 genes.Time series simulations were run using ordinary differential equations to generate level values for metabolites and flux values for reactions. Pathway maps were generated with NodeXL to include changes in metabolite levels, reaction fluxes, and gene expression levels for the reactions. Results: NodeXL is freeware that integrates into Microsoft Excel. Nodes were species and edges were reactions from the TTMÔ model. The nodes represented as spheres where
ALTERED ARGININE METABOLISM IN THE ALZHEIMER’S HIPPOCAMPUS
Ping Liu1, Michael Fleete1, Yu Jing1, Nicola Collie1, Maurice Curtis2, Richard Faull2, Wickliffe Abraham1, Hu Zhang3, 1University of Otago, Dunedin, New Zealand; 2University of Auckland, Auckland, New Zealand; 3 University of Otago, Dunedin, New Zealand. Contact e-mail: ping.liu@ otago.ac.nz Background: Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by progressive memory loss and neuropathological hallmarks of senile plaques and neurofibrillary tangles, with aging as a major risk factor. L-arginine is a semi-essential amino acid that can be metabolised to produce a number of bioactive metabolites. Accumulating evidence suggests that arginine metabolism may play a prominent role in AD pathogenesis. Methods: The present study conducted the enzyme assays, western blot, high-performance liquid chromatography and liquid chromatography mass spectroscopy to compare the L-arginine metabolic profiles in the hippocampus, a brain region that is affected early and severely in AD, in normal cases with an average age of 60 or 80 years and in AD cases with an average age of 80 years. Results: There were AD- and age-related reductions in total activity of nitric oxide synthase (NOS) and protein expression of the constitutive forms of NOS, and AD-related increases in arginase activity and arginase II protein expression. The level of L-ornithine was significantly decreased in the AD group only, with no significant differences between groups in L-arginine and L-citrulline. There were also AD- and age-related changes in putrescine, spermine and glutamate, with no changes in agmatine, spermidine and g -aminobutyric
Legend: Spheres are reactants (metabolites) and arrows are reactions. Both color and size of spheres reflect percent difference between groups; Only size of arrows reflects magnitude of percent difference between groups for flux in the direction of the arrow. Label on the arrows is the gene(s) responsible for the reaction and the color indicates percent difference in gene expression level. Green are lowest (negative) percent differences and orange to red are increasing positivity; brown color is no change. The highest increase was 25 hydroxycholesterol at 18%, bottom center. Two spheres are labeled (top left & bottom center) with percent change metabolite level values; cholesterol (bottom center) sphere size and color = 85% for scalar information. Flux changes range from 20 to 100%. The key pathways that make up the complete cholesterol biosynthetic pathway are labeled. *-mevalonate & squalence; **-FFMAS, ***-TMAS.