- Email: [email protected]
P1-091
Poster Presentations P1 a novel monoclonal antibody specific to A11-40/42 (JRF/hAb11/1), we examined whether targeting this fragment specifically would have any therapeutic effect in Tg2576 mice. Methods: Tg2576 transgenic mice were exposed to a chronic dosing regimen: JRF/hAb11/1 antibody or PBS was administered intraperitoneally, once a week, starting at the age of 6 months until 20 months. We measured levels of A11-40/42 in brain and plasma samples after treatment. The brains were also analyzed histologically for plaque deposition. Behavior tests, such as Y-maze and holeboard, were conducted to monitor cognitive function in these mice. Antibody-amyloid peptide interactions were characterized biophysically by surface plasmon resonance (SPR). Results: After treatment with JRF/hAb11/1, we observed increased plasma levels of both full length and truncated forms of A. Interestingly, mild improvements in cognitive function were observed during times when A levels are known to increase in this mouse model. Conclusions: JRF/hAb11/1 is a novel antibody that demonstrates specificity to the beta-amyloid fragment A11-40/42. Peripheral administration of this antibody in Tg2576 mice demonstrated a mild improvement in cognitive function during times of active A deposition. In vitro studies suggest that this antibody may be used to monitor progress or development of betaamyloid fibril maturation. P1-089
ALTERED NAVIGATIONAL STRATEGY USE AND VISUOSPATIAL IMPAIRMENTS IN HUMAN AMYLOID PRECURSOR PROTEIN TRANSGENIC MICE
Amy R. deIpolyi, Shanna Fang, Xin Wang, Lennart Mucke, Gladstone Institute of Neurological Disease, UCSF, San Francisco, CA, USA. Contact e-mail: [email protected] Background: Spatial navigation deficits are common in Alzheimer’s disease (AD) and recapitulated in transgenic mice with neuronal expression of familial AD-mutant human amyloid precursor protein (hAPP) and amyloid- (A) peptides. AD patients and hAPP mice show interindividual differences in the extent and pattern of these deficits. Objective: Here we assessed whether this variability is related to spatial strategy use. Methods: We assessed spatial learning in hAPP mice and nontransgenic controls with a cross maze task that could be solved by alternative strategies that did (allocentric) or did not (egocentric) depend on spatial landmarks outside of the maze, and with the Morris Water Maze (MWM) ending in probe trials favoring allocentric or egocentric search strategies. Results: In the cross maze, most 3- and 6-7-month-old nontransgenic mice used allocentric strategies, whereas over half of the hAPP mice used egocentric strategies. At 3 months, all mice learned the cross maze well. At 6-7 months, allocentric, but not egocentric, hAPP mice required significantly more training trials than nontransgenic controls. Expression of the neuronal activity marker Fos in the dentate gyrus was greater in allocentric than egocentric mice at 3 months and correlated with cross maze performance in allocentric, but not egocentric, hAPP mice at 6 months. Thus, egocentric strategy use may be a more sensitive and earlier indicator of AD-related hippocampal impairments than learning deficits in the cross maze. Expression of pCREB in the dorsomedial and dorsolateral striatum was associated with allocentric and egocentric strategies, respectively, and was not altered among hAPP mice compared with controls, consistent with the relative resistance of the striatum to AD. In the MWM, which requires allocentric strategies, allocentric and egocentric hAPP mice showed comparable age-dependent learning deficits. Conclusions: Failure to adopt striatum-dependent egocentric strategies may augment hAPP/Ainduced learning deficits in tasks that can be solved by either type of strategy. Interventions promoting the engagement of egocentric strategies might improve deficits in spatial navigation resulting from ADrelated hippocampal damage. Supported by NIH grants AG011385 and AG023501.
P1-090
S121 OBSERVATION OF NEW SENILE PLAQUE FORMATION AND ASSOCIATED NEURITIC ABNORMALITIES USING MULTIPHOTON MICROSCOPY
Melanie Meyer-Luehmann, Tara L. Spires, Brian J. Bacskai, Bradley T. Hyman, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. Contact e-mail: [email protected] Background: Senile plaque formation and neuronal alterations are characteristic features in the pathogenesis of Alzheimer’s disease (AD). We reported previously that amyloid plaques disrupt neuritic trajectories; however, it still remains unclear whether the changes in neuritic architecture precede plaque formation or if they are a later event in the pathogenesis. Objective: To address this question, we monitored young B6C3-YFP transgenic mice, which express yellow fluorescent protein (YFP) in a subset of neurons and develop plaques at the age of 5 months. Methods: Using in vivo multiphoton microscopy, we studied plaque formation and measured disrupted trajectories of neuronal processes associated with senile plaques. Results: Weekly imaging of the same neurons, dendrites and blood vessels revealed that newly formed plaques predominately develop close to, but not within blood vessels. Overall plaque size is remarkably stable once they have formed, even within the first few weeks after formation. Imaging on a daily basis further uncovered that plaques appear relatively suddenly, between one imaging session and the next, 24 hours later. After a plaque appears, progressive neuritic changes lead to increasingly curved, dysmorphic neurites over the next few days to weeks within the immediate vicinity of plaques. In addition, we also found a subtle increase in neuritic curvature even away from plaques (distance ⬎100 m) in APP/PS1-YFP mice when compared to YFP transgenic control mice. Conclusion: Our results suggest that plaque-related neuritic changes are a direct consequence of dense-cored plaque formation; subtle changes distant from plaques may imply long-range effects of plaques or may be a consequence of non-fibrillar forms of A. This work was supported by National Institutes of Health Grant AG08487 and Alzheimer Association Pioneer Award EB00768. P1-091
ABERRANT PHOSPHORYLATION OF THE HUMAN TAU GENE IN TRANSGENIC MICE WITH ALZHEIMER’S DISEASE
Sun B. Shim, Hwa J. Lim, Jung S. Cho, Chuel K. Kim, Dae Y. Hwang, Seung W. Jee, Su H. Lee, Se H. Lee, Yong K. Kim, Kore Food & Drug Administration, Seoul, Republic of Korea. Contact e-mail: [email protected] Background: The abnormal phosphorylation of these tau-binding proteins plays a key role in the neuropathology of AD. Objective(s): The aim of this study was to investigate how the overexpression of tau interacts and regulates the behavior and phosphorylation of the tau-binding proteins, and whether or not it is associated with Wnt signal. This approach offers a critical insight that might have an impact on the neuronal degeneration in AD. Methods: Transgenic mice expressing NSE-controlled-htau24 were created to address the hypothesis that the over-expression of the htau24 transgene leads to the behavior deficits and modulated phosphorylation of tau-binding proteins including GSK3, -catenin, and presenilin 1. Results: This study showed the following: (1) transgenic mice exhibiting NSE-hTau24 transgeneration. (2) The htau protein and its phosphorylation occurred abundantly in the tau brain of the NSE-htau24-harboring mice. (3) PHF deposits were more abundant in the brains of the Tg group, and resulted in the neuronal degeneration observed in the Tg group. (4) High levels of GSK3 phosphorylation in an age-dependent manner, leading to an increase in tau and -catenin phosphorylation and PS1 activation. (5) Behavior impairment is not induced by Lithium Chloride treatment in tau mice. (6) The non-tg groups exhibit some resistance against lithium treatment, which prevents the reduction of -catenin levels in the cytosol and nuclei and the abnormal phosphorylation of tau, via the blockage of GSK3 phosphorylation. Conclusions: Therefore, htau24 overexpression
S122
Poster Presentations P1
in transgenic mice induces an altered phosphorylation in tau-binding protein and behavioral deficits, which are ultimately linked to neuronal degeneration in AD. In parallel, altered expressions of these transgenic mice are expected to be useful targets in developing new therapeutic treatments. P1-092
EARLY EFFECTS OF BETA-AMYLOID ON SYNAPSES, ALPHA7 NACHRS, NMDARS AND SIGNAL TRANSDUCTION IN APPSWE TRANSGENIC MICE
Tamanna Mustafiz, Christina Unger, Monika M. Hedberg, Marie M. Svedberg, Agneta Nordberg, Karolinska Institutet, Stockholm, Sweden. Contact e-mail: [email protected] Background: Alzheimer’s disease (AD) is the most common form of dementia, characterized by progressive memory impairment as a consequence of loss of synapses, neuritic plaques, neurofibrillary tangles and gliosis, primarily in the hippocampus and cortical brain regions. A decrease in the number of synapses has been observed to strongly correlate to the cognitive impairment of AD patients. According to “The Amyloid Hypothesis”, hyper-production of amyloid- peptide (A) would ultimately lead to a cascade of neurodegenerative events due to the toxic effect of amyloid precursor protein (APP) metabolism on neuronal structures. Although genetic and biochemical studies have suggested a cardinal role for A, the underlying mechanism(s) of how A induces degeneration in the central nervous system is still unclear. The Tg 2576 (APPswe) mice develop age-related amyloid deposition as well as behavioral- and electrophysiological changes in the brain. Objective(s): To investigate the effect of early A in the brain of APPswe transgenic mice. Methods: APPswe mice were investigated from 7 to 90 days of age. A, synaptophysin, ␣7 nAChRs and NMDARs as well as the MAPK signal transduction pathways were investigated. Results: We observed high A levels in the cortex of APPswe mice at 7 days of age, suggesting that these mice produce A from birth. The high levels of A early in the life of the APPswe transgenic mice also caused a shift in the synaptophysin levels, followed by changes in ERK, p38 and JNK MAPK activity, indicating that A causes altered synaptic function and an increase in the number of synaptic terminals. In addition, alterations in [125I]␣bungarotoxin- and [3H]MK-801 binding sites were also observed in APPswe mice compared to controls. Conclusions: In conclusion, over-expression of A early in life causes changes in synaptophysin levels and number of [125I]␣bungarotoxin- and [3H]MK-801 binding sites. The results may provide important information about the onset and consequences of A pathology in this transgenic mouse model. P1-093
SERIAL MRI REVEALS DIFFERENCES IN TEMPORAL TRENDS OF TRANSVERSE RELAXATION TIME (T2) BETWEEN WILDTYPE AND TRANSGENIC (ALZHEIMER’S DISEASE) MICE
Herve´ Barjat, Andreas Pohlmann, Sean C. Smart, Lorna C. Tilling, Neil Upton, Michael F. James, GlaxoSmithKline, Harlow, United Kingdom. Contact e-mail: [email protected] Background: TASTPM transgenic (Tg) mice over-express the Alzheimer’s disease (AD)-associated human proteins APP(K670N, M671L) ⫻ PS1(M146V) under the Thy-1 promoter. Cerebral A is progressively deposited, and is widespread at 6 month. Objective(s): We imaged TASTPM (n⫽7-18) and wildtype (WT, n⫽13-15) strains at 6, 9, 11, and 14 months of age to investigate if the progressive changes in transgenic mouse brains can be measured non-invasively in-vivo. Methods: Experiments complied with GSK ethical and UK legal requirements. For MRI at 4.7T under gaseous anaesthesia, the head was immobilized within the imaging coils; recovery was uneventful. A CPMG multi-slice multi-echo (TR/TE⫽5400/ 10.5-84.5ms) dataset was obtained, voxel size 78x78x156 m. T2 maps were affine registered (FSL, FMRIB, Oxford University) to an in-house template. To highlight areas of significant T2 change, pixel-wise t-tests were performed on Gaussian smoothed Tg and WT T2-maps. Tg-specific
significant changes in the frontal cortex (FrCx) and thalamus (Th) are reported here. Mean T2 was calculated from the original unsmoothed data for ROIs in several adjacent slices of the FrCx (3 slices, mean area 7.81⫾0.58mm2, volume 3.66mm3, Cg1⫹Cg2⫹M1⫹M2⫹S1, enclosing all FrCx hotspots) and the Th (2 slices, 1.83⫾0.32mm2, 0.57mm3, hotspots only). Results: In the FrCx T2 remained unchanged with age in WT mice but decreased in Tg animals, while in the Th T2 decreased in WT mice but increased in Tg animals. At 6m no significant T2 differences were present between WT and Tg (FrCx ⌬T2⬍0.43%, Th ⌬T2⬍0.89%) with T2 being 60.25⫾0.20ms (mean[WT,Tg] ⫾ SD) in the FrCx-ROIs and 55.59⫾0.38ms in the Th-ROIs. However, at 14m differences were significant in FrCx-ROIs ([T2Tg-T2WT]/T2WT ⫽ -1.78%, p⫽0.007; -1.59%, p⫽0.017; -1.64%, p⫽0.014) and Th-ROIs (⫹4.70%, p⬍0.001; ⫹5.00%, p⬍0.001). Conclusions: The observed T2 changes in the cortex coincide with regions of high amyloid burden and agree with findings of Falangola et al (2005) at 18 months and 7T, also comparing transgenic (PS/APP) and non-transgenic mice. T2 changes in the thalamic foci may be related to underlying processes (e.g. amyloid deposition, inflammation) that caused magnetic anomalies in similar regions of the thalamus, as detected by T2*-imaging in the same animals. P1-094
NEW TRANSGENIC TAU MOUSE MODEL WITH COGNITIVE DISTURBANCES
Birgit Hutter-Paier, Alexander Hofmeister, Manuela Prokesch, Ulrike Bauer, Maria Posch, Manfred Windisch, JSW-Research, Graz, Austria. Contact e-mail: [email protected] Background: Tauopathies are represented by fronto-temporal dementia, with Parkinsonism linked to chromosome 17 (FTDP-17), amyotrophic lateral sclerosis/parkinsonism-dementia complex, Alzheimer’s disease and progressive supranuclear palsy. These diseases are characterized by numerous inclusions, formed by paired helical filaments (PHFs) or filaments composed of hyper-phosphorylated TAU proteins in many brain regions. Several mutations of TAU have been described. Some missense mutations (G272V - exon 9, V337M - exon 12 and R406W - exon 13) affect all isoforms produced, while for example P301L only alters those isoforms with 4 repeats. The R406W tau mutation found in FTDP-17 causes a hereditary tauopathy clinically resembling Alzheimer’s disease. The mutation V337M leads to a loss of function of the tau isoforms and provokes microtubule destabilization and tau aggregation. Objective(s): We generated transgenic mice overexpressing human TAU441 gene with two mutations, V337M and R406W, under the control of a tissue specific murine Thy1-promoter. As genetic background C57Bl/6J X CB6 inbred mice were used. Methods: From 7 founders offsprings were investigated in terms of TAU RNA and protein content in specific brain regions. Finally 3 different lines with high TAU expression were further characterized. The expanded phenotyping comprised evaluation of cognitive changes, of motor function and especially brain morphology. Results: None of the investigated animals showed signs of motoric disturbances up to an age of 14 months. These results are supported by Rotarod experiments in 9 month old animals showing no disturbance at all. In two out of three lines spatial navigation behaviour in the MWM is severely disturbed compared to littermates. The histological evaluation of TAU pathology in the cortex using the AT180 antibody which detects PHF and tangles (Thr231) revealed numerous densely packed TAU-positive lesions i.e. abnormal TAU-immunoreactive neuropil fibers and tangles. Massive TAU depositions can be seen in neuronal soma and axon, the latter densely packed with TAU. In the hippocampus accentuated TAU accumulation is visible, apparently seen in the periventricular matter. Conclusions: Further investigations will mainly focus on neuronal cell death, the final step in tauopathies like Alzheimer’s disease. So far these TAU mouse lines exhibit promising features, relevant for drug testing.
ALTERED NAVIGATIONAL STRATEGY USE AND VISUOSPATIAL IMPAIRMENTS IN HUMAN AMYLOID PRECURSOR PROTEIN TRANSGENIC MICE
Amy R. deIpolyi, Shanna Fang, Xin Wang, Lennart Mucke, Gladstone Institute of Neurological Disease, UCSF, San Francisco, CA, USA. Contact e-mail: [email protected] Background: Spatial navigation deficits are common in Alzheimer’s disease (AD) and recapitulated in transgenic mice with neuronal expression of familial AD-mutant human amyloid precursor protein (hAPP) and amyloid- (A) peptides. AD patients and hAPP mice show interindividual differences in the extent and pattern of these deficits. Objective: Here we assessed whether this variability is related to spatial strategy use. Methods: We assessed spatial learning in hAPP mice and nontransgenic controls with a cross maze task that could be solved by alternative strategies that did (allocentric) or did not (egocentric) depend on spatial landmarks outside of the maze, and with the Morris Water Maze (MWM) ending in probe trials favoring allocentric or egocentric search strategies. Results: In the cross maze, most 3- and 6-7-month-old nontransgenic mice used allocentric strategies, whereas over half of the hAPP mice used egocentric strategies. At 3 months, all mice learned the cross maze well. At 6-7 months, allocentric, but not egocentric, hAPP mice required significantly more training trials than nontransgenic controls. Expression of the neuronal activity marker Fos in the dentate gyrus was greater in allocentric than egocentric mice at 3 months and correlated with cross maze performance in allocentric, but not egocentric, hAPP mice at 6 months. Thus, egocentric strategy use may be a more sensitive and earlier indicator of AD-related hippocampal impairments than learning deficits in the cross maze. Expression of pCREB in the dorsomedial and dorsolateral striatum was associated with allocentric and egocentric strategies, respectively, and was not altered among hAPP mice compared with controls, consistent with the relative resistance of the striatum to AD. In the MWM, which requires allocentric strategies, allocentric and egocentric hAPP mice showed comparable age-dependent learning deficits. Conclusions: Failure to adopt striatum-dependent egocentric strategies may augment hAPP/Ainduced learning deficits in tasks that can be solved by either type of strategy. Interventions promoting the engagement of egocentric strategies might improve deficits in spatial navigation resulting from ADrelated hippocampal damage. Supported by NIH grants AG011385 and AG023501.
P1-090
S121 OBSERVATION OF NEW SENILE PLAQUE FORMATION AND ASSOCIATED NEURITIC ABNORMALITIES USING MULTIPHOTON MICROSCOPY
Melanie Meyer-Luehmann, Tara L. Spires, Brian J. Bacskai, Bradley T. Hyman, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. Contact e-mail: [email protected] Background: Senile plaque formation and neuronal alterations are characteristic features in the pathogenesis of Alzheimer’s disease (AD). We reported previously that amyloid plaques disrupt neuritic trajectories; however, it still remains unclear whether the changes in neuritic architecture precede plaque formation or if they are a later event in the pathogenesis. Objective: To address this question, we monitored young B6C3-YFP transgenic mice, which express yellow fluorescent protein (YFP) in a subset of neurons and develop plaques at the age of 5 months. Methods: Using in vivo multiphoton microscopy, we studied plaque formation and measured disrupted trajectories of neuronal processes associated with senile plaques. Results: Weekly imaging of the same neurons, dendrites and blood vessels revealed that newly formed plaques predominately develop close to, but not within blood vessels. Overall plaque size is remarkably stable once they have formed, even within the first few weeks after formation. Imaging on a daily basis further uncovered that plaques appear relatively suddenly, between one imaging session and the next, 24 hours later. After a plaque appears, progressive neuritic changes lead to increasingly curved, dysmorphic neurites over the next few days to weeks within the immediate vicinity of plaques. In addition, we also found a subtle increase in neuritic curvature even away from plaques (distance ⬎100 m) in APP/PS1-YFP mice when compared to YFP transgenic control mice. Conclusion: Our results suggest that plaque-related neuritic changes are a direct consequence of dense-cored plaque formation; subtle changes distant from plaques may imply long-range effects of plaques or may be a consequence of non-fibrillar forms of A. This work was supported by National Institutes of Health Grant AG08487 and Alzheimer Association Pioneer Award EB00768. P1-091
ABERRANT PHOSPHORYLATION OF THE HUMAN TAU GENE IN TRANSGENIC MICE WITH ALZHEIMER’S DISEASE
Sun B. Shim, Hwa J. Lim, Jung S. Cho, Chuel K. Kim, Dae Y. Hwang, Seung W. Jee, Su H. Lee, Se H. Lee, Yong K. Kim, Kore Food & Drug Administration, Seoul, Republic of Korea. Contact e-mail: [email protected] Background: The abnormal phosphorylation of these tau-binding proteins plays a key role in the neuropathology of AD. Objective(s): The aim of this study was to investigate how the overexpression of tau interacts and regulates the behavior and phosphorylation of the tau-binding proteins, and whether or not it is associated with Wnt signal. This approach offers a critical insight that might have an impact on the neuronal degeneration in AD. Methods: Transgenic mice expressing NSE-controlled-htau24 were created to address the hypothesis that the over-expression of the htau24 transgene leads to the behavior deficits and modulated phosphorylation of tau-binding proteins including GSK3, -catenin, and presenilin 1. Results: This study showed the following: (1) transgenic mice exhibiting NSE-hTau24 transgeneration. (2) The htau protein and its phosphorylation occurred abundantly in the tau brain of the NSE-htau24-harboring mice. (3) PHF deposits were more abundant in the brains of the Tg group, and resulted in the neuronal degeneration observed in the Tg group. (4) High levels of GSK3 phosphorylation in an age-dependent manner, leading to an increase in tau and -catenin phosphorylation and PS1 activation. (5) Behavior impairment is not induced by Lithium Chloride treatment in tau mice. (6) The non-tg groups exhibit some resistance against lithium treatment, which prevents the reduction of -catenin levels in the cytosol and nuclei and the abnormal phosphorylation of tau, via the blockage of GSK3 phosphorylation. Conclusions: Therefore, htau24 overexpression
S122
Poster Presentations P1
in transgenic mice induces an altered phosphorylation in tau-binding protein and behavioral deficits, which are ultimately linked to neuronal degeneration in AD. In parallel, altered expressions of these transgenic mice are expected to be useful targets in developing new therapeutic treatments. P1-092
EARLY EFFECTS OF BETA-AMYLOID ON SYNAPSES, ALPHA7 NACHRS, NMDARS AND SIGNAL TRANSDUCTION IN APPSWE TRANSGENIC MICE
Tamanna Mustafiz, Christina Unger, Monika M. Hedberg, Marie M. Svedberg, Agneta Nordberg, Karolinska Institutet, Stockholm, Sweden. Contact e-mail: [email protected] Background: Alzheimer’s disease (AD) is the most common form of dementia, characterized by progressive memory impairment as a consequence of loss of synapses, neuritic plaques, neurofibrillary tangles and gliosis, primarily in the hippocampus and cortical brain regions. A decrease in the number of synapses has been observed to strongly correlate to the cognitive impairment of AD patients. According to “The Amyloid Hypothesis”, hyper-production of amyloid- peptide (A) would ultimately lead to a cascade of neurodegenerative events due to the toxic effect of amyloid precursor protein (APP) metabolism on neuronal structures. Although genetic and biochemical studies have suggested a cardinal role for A, the underlying mechanism(s) of how A induces degeneration in the central nervous system is still unclear. The Tg 2576 (APPswe) mice develop age-related amyloid deposition as well as behavioral- and electrophysiological changes in the brain. Objective(s): To investigate the effect of early A in the brain of APPswe transgenic mice. Methods: APPswe mice were investigated from 7 to 90 days of age. A, synaptophysin, ␣7 nAChRs and NMDARs as well as the MAPK signal transduction pathways were investigated. Results: We observed high A levels in the cortex of APPswe mice at 7 days of age, suggesting that these mice produce A from birth. The high levels of A early in the life of the APPswe transgenic mice also caused a shift in the synaptophysin levels, followed by changes in ERK, p38 and JNK MAPK activity, indicating that A causes altered synaptic function and an increase in the number of synaptic terminals. In addition, alterations in [125I]␣bungarotoxin- and [3H]MK-801 binding sites were also observed in APPswe mice compared to controls. Conclusions: In conclusion, over-expression of A early in life causes changes in synaptophysin levels and number of [125I]␣bungarotoxin- and [3H]MK-801 binding sites. The results may provide important information about the onset and consequences of A pathology in this transgenic mouse model. P1-093
SERIAL MRI REVEALS DIFFERENCES IN TEMPORAL TRENDS OF TRANSVERSE RELAXATION TIME (T2) BETWEEN WILDTYPE AND TRANSGENIC (ALZHEIMER’S DISEASE) MICE
Herve´ Barjat, Andreas Pohlmann, Sean C. Smart, Lorna C. Tilling, Neil Upton, Michael F. James, GlaxoSmithKline, Harlow, United Kingdom. Contact e-mail: [email protected] Background: TASTPM transgenic (Tg) mice over-express the Alzheimer’s disease (AD)-associated human proteins APP(K670N, M671L) ⫻ PS1(M146V) under the Thy-1 promoter. Cerebral A is progressively deposited, and is widespread at 6 month. Objective(s): We imaged TASTPM (n⫽7-18) and wildtype (WT, n⫽13-15) strains at 6, 9, 11, and 14 months of age to investigate if the progressive changes in transgenic mouse brains can be measured non-invasively in-vivo. Methods: Experiments complied with GSK ethical and UK legal requirements. For MRI at 4.7T under gaseous anaesthesia, the head was immobilized within the imaging coils; recovery was uneventful. A CPMG multi-slice multi-echo (TR/TE⫽5400/ 10.5-84.5ms) dataset was obtained, voxel size 78x78x156 m. T2 maps were affine registered (FSL, FMRIB, Oxford University) to an in-house template. To highlight areas of significant T2 change, pixel-wise t-tests were performed on Gaussian smoothed Tg and WT T2-maps. Tg-specific
significant changes in the frontal cortex (FrCx) and thalamus (Th) are reported here. Mean T2 was calculated from the original unsmoothed data for ROIs in several adjacent slices of the FrCx (3 slices, mean area 7.81⫾0.58mm2, volume 3.66mm3, Cg1⫹Cg2⫹M1⫹M2⫹S1, enclosing all FrCx hotspots) and the Th (2 slices, 1.83⫾0.32mm2, 0.57mm3, hotspots only). Results: In the FrCx T2 remained unchanged with age in WT mice but decreased in Tg animals, while in the Th T2 decreased in WT mice but increased in Tg animals. At 6m no significant T2 differences were present between WT and Tg (FrCx ⌬T2⬍0.43%, Th ⌬T2⬍0.89%) with T2 being 60.25⫾0.20ms (mean[WT,Tg] ⫾ SD) in the FrCx-ROIs and 55.59⫾0.38ms in the Th-ROIs. However, at 14m differences were significant in FrCx-ROIs ([T2Tg-T2WT]/T2WT ⫽ -1.78%, p⫽0.007; -1.59%, p⫽0.017; -1.64%, p⫽0.014) and Th-ROIs (⫹4.70%, p⬍0.001; ⫹5.00%, p⬍0.001). Conclusions: The observed T2 changes in the cortex coincide with regions of high amyloid burden and agree with findings of Falangola et al (2005) at 18 months and 7T, also comparing transgenic (PS/APP) and non-transgenic mice. T2 changes in the thalamic foci may be related to underlying processes (e.g. amyloid deposition, inflammation) that caused magnetic anomalies in similar regions of the thalamus, as detected by T2*-imaging in the same animals. P1-094
NEW TRANSGENIC TAU MOUSE MODEL WITH COGNITIVE DISTURBANCES
Birgit Hutter-Paier, Alexander Hofmeister, Manuela Prokesch, Ulrike Bauer, Maria Posch, Manfred Windisch, JSW-Research, Graz, Austria. Contact e-mail: [email protected] Background: Tauopathies are represented by fronto-temporal dementia, with Parkinsonism linked to chromosome 17 (FTDP-17), amyotrophic lateral sclerosis/parkinsonism-dementia complex, Alzheimer’s disease and progressive supranuclear palsy. These diseases are characterized by numerous inclusions, formed by paired helical filaments (PHFs) or filaments composed of hyper-phosphorylated TAU proteins in many brain regions. Several mutations of TAU have been described. Some missense mutations (G272V - exon 9, V337M - exon 12 and R406W - exon 13) affect all isoforms produced, while for example P301L only alters those isoforms with 4 repeats. The R406W tau mutation found in FTDP-17 causes a hereditary tauopathy clinically resembling Alzheimer’s disease. The mutation V337M leads to a loss of function of the tau isoforms and provokes microtubule destabilization and tau aggregation. Objective(s): We generated transgenic mice overexpressing human TAU441 gene with two mutations, V337M and R406W, under the control of a tissue specific murine Thy1-promoter. As genetic background C57Bl/6J X CB6 inbred mice were used. Methods: From 7 founders offsprings were investigated in terms of TAU RNA and protein content in specific brain regions. Finally 3 different lines with high TAU expression were further characterized. The expanded phenotyping comprised evaluation of cognitive changes, of motor function and especially brain morphology. Results: None of the investigated animals showed signs of motoric disturbances up to an age of 14 months. These results are supported by Rotarod experiments in 9 month old animals showing no disturbance at all. In two out of three lines spatial navigation behaviour in the MWM is severely disturbed compared to littermates. The histological evaluation of TAU pathology in the cortex using the AT180 antibody which detects PHF and tangles (Thr231) revealed numerous densely packed TAU-positive lesions i.e. abnormal TAU-immunoreactive neuropil fibers and tangles. Massive TAU depositions can be seen in neuronal soma and axon, the latter densely packed with TAU. In the hippocampus accentuated TAU accumulation is visible, apparently seen in the periventricular matter. Conclusions: Further investigations will mainly focus on neuronal cell death, the final step in tauopathies like Alzheimer’s disease. So far these TAU mouse lines exhibit promising features, relevant for drug testing.