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P4-157 EXPERIMENTAL DIABETES MELLITUS

EXACERBATES TAU PATHOLOGY IN P301L-TAU

TRANSGENIC MOUSE MODEL

Yazi D. Ke, Amadeus Gladbach, Fabien Delerue, Jurgen Gotz, Lars Ittner,

University of Sydney, Sydney, Australia. Contact e-mail: yke@med.usyd.

edu.au.

Background: Diabetes mellitus (DM) is characterized by hyperglycemia

due to a lack of insulin, insulin resistance, or both. There is increasing ev-

idence that insulin also plays a role in Alzheimer’s disease (AD) as it is in-

volved in the metabolism of amyloid-beta and tau, two proteins that form

amyloid-beta plaques and neurofibrillary tangles (NFTs), respectively.

Here, the effects of experimentally- induced DM on a pre-existing tau pa-

thology in mutant tau transgenic mice were examined.Methods: pR5 mice

express P301L mutant human tau under the murine Thy1.2 promoter with

increased phosphorylated of tau with age as well as tangle formation at

eight months of age. Experimental DM was induced by administration of

streptozotocin (STZ), which causes insulin deficiency. Phosphorylation

of tau was determined using immunohistochemistry and Western blotting.

Solubility of tau was determined by extraction with sarkosyl and formic

acid, and Gallyas silver staining was used to identify NFTs present. Re-

sults: Insulin depletion by STZ administration in six months old non-trans-

genic mice resulted in an increase in tau phosphorylation, however this

occurred without formation or deposition of NFTs. In contrast, in six

months old pR5 mice STZ-induced insulin depletion resulted in increased

hyperphosphorylation and insolubility of tau as well as NFT formation. In

comparison, the pathology in sham-treated pR5 mice was moderate. Con-

clusions: Whereas experimental DM did not result in deposition of hyper-

phosphorylated tau in non-transgenic mice, a predisposition to develop tau

pathology in young pR5 mice was both sufficient and necessary to exacer-

bate tau deposition and NFT formation. Hence, DM may accelerate onset

and increase severity of disease in individuals with a predisposition to

developing tau pathology.

P4-158 FLUOROISOINDOLONE DERIVATIVES AS

POTENTIAL PET IMAGING AGENTS FOR

DETECTION OF BETA-AMYLOID FIBRILS

Jiyeon Choi1, YoungSoo Kim1, Ji Hoon Lee1, Soo Jeong Lim2,

Seung Jun Oh2, Dae Hyuk Moon2, Dong Jin Kim1, 1Korea Institute of Sci-

ence & Technology, Seoul, Korea, Republic of; 2Asan Medical Center,

Seoul, Korea, Republic of. Contact e-mail: jychoi@kist.re.kr.

Background: Alzheimer’s disease (AD) is pathologically characterized by

the accumulation of amyloid plaques and neurofibrillary tangles in the

brain. Such plaques can be excellent targets for in vivo brain imaging of

AD patients as an early diagnosis of AD. Development of imaging probes

for direct marking of Ab aggregates in the living brain is a highly active

research area in recent years. For instance, Pittsburgh compound B

(PIB), a derivative of Thioflavin T with high binding affinity to b-amyloid

(Ab) fibrils, is the most common imaging agent used in investigational

studies of AD via positron emission tomography (PET). Methods: In

this study a novel series of fluoroisoindolone derivatives for Ab specific

binding agents is described. Cold compounds, labeled with 19F for a bind-

ing study, were synthesized and evaluated by a competitive binding assay

with [125I]TZDM against Ab(1-42) aggregates. [18F]-labeled isoindole de-

rivatives, hot compounds, were evaluated as potential Ab imaging agents

based on their in vivo pharmacokinetic studies using micro-PET. Results:

Most of the synthesized compounds displayed higher binding affinities,

with Ki value in the subnanomolar than PIB (Ki ¼ 0.77 nM). Most of

the radio-labeled compounds showed high brain uptake and excellent

clearance in normal mice. Ab fibril labeling abilities were confirmed via

ex vivo staining on brain tissues of AD transgenic mice. Conclusions:

The preliminary results suggest that these [18F]-labeled compounds are

potential PET imaging probes for studying accumulation of Ab fibrils in

the brains of AD patients.

P4-159 LRP9, A NEW PLAYER IN ALZHEIMER’S DISEASE

Julie Brodeur, Christine Lavoie, Universite de Sherbrooke, Sherbrooke,

QC, Canada. Contact e-mail: Christine.L.Lavoie@USherbrooke.ca.

Background: Amyloid-b peptide (Ab) production and accumulation in the

brain is a central event in the pathogenesis of Alzheimer’s disease (AD). Ab

is derived from the amyloid precursor proteins (APP) by sequential prote-

olysis by enzymes called secretases. These enzymes are localized in differ-

ent compartments in the cells and the transport of APP to these specific

compartments leads to its cleavage by the secretases. Therefore understand-

ing how APP is moved around is central to developing therapies for AD

treatment. Various members of the LDLR family (LRP1, SorLA) have

been found to interact with APP and to regulate its trafficking and process-

ing. We recently characterized a new member of the LDLR family called

LRP9 which cycles between the trans-Golgi Network (TGN) and endo-

somes. LRP9 C-tail is unique since it contains two DXXLL motifs (that

bind clathrin adaptors GGAs) that are crucial for LRP9 trafficking since

their mutation (DXXAA) caused a redistribution of LRP9 to the endosomes

and plasma membrane. LRP9 homology to the sorting receptor SorLA that

shuttles APP between the TGN and endosomes leads us to hypothesize that

LRP9 is a functional APP receptor involved in APP trafficking and process-

ing.Methods: Studies were performed in CHO cells stably expressing APP

alone or together with LRP9 wild-type or DXXAAmutant. The distribution

of APP and LRP9 was analyzed using confocal microscopy. Interactions

were tested by immunoprecipitation. APP level, half-life and maturation

were studied by western blots and 35S-methionine pulse-chase assays. Re-

sults: Confocal microscopy studies showed that LRP9 colocalizes with

APP at the TGN. Expression of LRP9-DXXAA mutant led to a redistribu-

tion of APP from the TGN to early endosomes. Immunoprecipitation stud-

ies indicated an interaction of APP with both the cytoplasmic and luminal

domain of LRP9. Furthermore, overexpression of LRP9 wild-type de-

creased the cellular levels of APP as well as its maturation. To assess the

functional importance of LRP9 on APP, we are presently analyzing the gen-

eration of APP processing products.Conclusions:Our data show that LRP9

binds to APP and modulates its intracellular distribution as well as its

maturation, strengthening the potential role of LRP9 as a novel APP sorting

receptor.

P4-160 NEUROPATHOLOGICAL CHANGES INADULTAND

OLD RATS FOLLOWING EARLY POST-NATAL

IRON ADMINISTRATION: MYABSTRACT

Liana L. Fernandez1, Maria Noemia Martins de Lima2, Felipe Scalco2,

Gustavo Vedana2, Clıvia Miwa2, Arlete Hilbig1, Nadja Schroder2, 1UFC-

SPA, Porto Alegre, Brazil; 2PUCRS, Porto Alegre, Brazil.

Background: The present study was aimed to investigate neuropathological

changes in adult and old rats subjected to supplementary iron administration

in a critical postnatal period in order to study the contribution of environ-

mental risk factors to the pathogenesis of neurodegenerative disorders.

Methods: Ten rats received iron between 12th and 14th post-natal days; 9

rats received vehicle (sorbitol 5% in water) in the same period. Five iron-

treated and 3 sorbitol-treated rats were killed at the age of 3 months while

5 iron-treated and 6 sorbitol-treated rats were killed at age of 24 months

and their brains processed for immunohistochemistry. Results: No signifi-

cant differences in b-amyloid, phosphorylated tau and a-synuclein were

seen when iron-treated and iron-non-treated rats were compared. Increased

astrocytosis, revealed by densitometry of GFAP-immnoreactive astrocytes,

was found in old (24 months) iron-treated rats in substantia nigra and

striatum and in the hippocampus of adult (3 months) iron-treated rats

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when compared to age-matching controls. Decreased neurons, revealed by

densitometry of NeuN, was found in substantia nigra and striatum of old-

iron-treated rats. No differences was found in hippocampus. Conclusions:

These findings suggest that transient dietary iron supplementation during

the neonatal period is associated to cellular imprinting in the brain later in

life.

P4-161 INCIDENCE AND SEVERITY OF DEPOSITION OF

AMYLOID BETA PROTEIN IN THE PRECUNEUS

AND THE POSTERIOR CINGULATE GYRUS IN AN

AGING COHORT

Hiroyuki Hatsuta1, Yuko Saito2, Tadashi Adachi1, Tomio Arai3,

Motoji Sawabe3, Kenji Ishii4, Akinori Miyashita5, Ryozo Kuwano5,

Shigeo Murayama1, 1Tokyo Metropolitan Geriatric Hospital & Institute of

Gerontology, Tokyo, Japan; 2National Center Hospital of Neurology and

Psychiatry, Tokyo, Japan; 3Tokyo Metropolitan Geriatric Hospital, Tokyo,

Japan; 4Positron Medical Center, Tokyo Metropolitan Institute of Geron-

tology, Tokyo, Japan; 5Bioresource Science Branch, Center for Bioresour-

ces, Brain Research Institute, Niigata, Japan. Contact e-mail: xauyda@

tmig.or.jp.

Background:Accumulation of 11C-PIB in posterior cingulate gyrus (PCG)

is reported to be characteristic of Alzheimer’s disease.We propose a hypoth-

esis that poor spatial resolution of the PET could not distinguish the accu-

mulation in adjacent precuneus (Pc) (parietal neocortex) and in PCG

(limbic allocortex). Methods: Brains from 219 consecutive autopsy cases

from a general geriatric hospital between 2005 and 2008 were employed

for this study. The brains were fixed in formalin and 6 mm-thick serial sec-

tions were obtained from the paraffin blocks of the middle frontal gyrus (F),

superior temporal gyrus (T), supramarginal gyrus (P), Pc, the valley (transi-

tional cortex) and crown (allocortex) of PCG. The sections were immuno-

histochemically stained with anti-amyloid beta (Abeta) 11-28 and 1-40

antibodies. The incidence of senile plaques (SPs) in total cases (SP inci-

dence) and the percentage of the area occupied by SPs in the gray matter

of each cortex (defined as SP ratio) were calculated with a virtual slide

maker (Aperio) and a software for histoanalysis (Image Pro plus). APOE

genotyping was done with both direct sequencing and a TaqMan assay. Re-

sults: SP incidence and ratio with that of APOE e4 carriers (39 cases) and

non carriers (177 cases) in each parenthesis were as follows: Pc, 76.0%

(97.4%, 71.2%*), 3.77%* (6.25%*, 3.28%*); the valley of PCG, 71.7%

(94.9%, 66.7%*), 3.36%* (6.07%, 2.82%); the crown of PCG, 67.1%*

(92.3%, 61.6%*), 2.07%* (3.59%*, 1.77%*); F, 76.7% (97.4%, 72.3%),

3.07% (4.89%, 2.71%); T, 70.8% (94.9%, 65.5%*), 3.11% (5.53%*,

2.62%); and P, 69.0%* (97.4%, 68.4%), 2.84% (5.43%, 3.04%*). The

asterisks (*) represent significant results (p <0.05 compared with F).

Conclusions: SP incidence of Pc was higher and that of the crown of

PCG was lower than that of F. SP ratio, either with or without APOE e4

allele, showed the same results. They suggest careful delineation of Pc

and PCG byMRI guidance in amyloid PET study is important for histopath-

ological correlation.

P4-162 GRK5 DEFICIENCY PROMOTES Aß

ACCUMULATION AND EXAGGERATES BRAIN

INFLAMMATION

William Z. Suo1,2, 1Veterans Affairs Medical Center, Kansas City, MO,

USA; 2University of Kansas Medical Center, Kansas City, KS, USA.

Contact e-mail: zsuo@kumc.edu.

Background: Recent studies have established a clear link between mem-

brane G-protein coupled receptor (GPCR) kinase-5 (GRK5) deficiency and

Alzheimer’s disease (AD). Some pathologic impact of the GRK5 defi-

ciency have been revealed, such as (1) impairing presynaptic M2 receptor

desensitization and reducing acetylcholine release; (2) promoting hippo-

campal axonal/synaptic degeneration; and (3) exaggerating brain inflam-

matory responses. Potential roles of the GRK5 deficiency in several

other important AD pathogenic processes, such as ß-amyloid (Aß) accu-

mulation and tau phosphorylation, remain unknown. In addition, we

have previously speculated that the exaggerated brain inflammation by

the GRK5 deficiency could be caused either by impaired desensitization

of GPCR inflammatory mediators or by increased fibrillar Aß deposits,

but it also needs to be determined. The objectives of this study are to in-

vestigate impact of the GRK5 deficiency on Aß accumulation and its rela-

tion to the exaggerated brain inflammation. Methods: Both quantitative

and qualitative immunohistochemistry (IHC) and Western blotting were

used to evaluate changes of Aß and gliosis in GRK5 deficient APPsw

mice (GRK5KO/APPsw), and their correlations were analyzed. Results:

Our Western blotting analyses revealed that not only did the SDS-soluble

Aß level increase but also the secreted ßAPP fragment (sAPPß) increased

as well in the GRK5KO/APPsw mice, suggesting that an altered APP pro-

cessing occurred in these mice in favor of ß-amyloidogenesis. In addition,

IHC examinations found that there was significantly increased Aß+ plaque

burden in hippocampus and cortical areas of the double mice as compared

to the APPsw control mice. Moreover, the increased fibrillar Aß deposits

closely colocalized with the exaggerated microgliosis and astrogliosis

that we previously observed. Correlation analysis indicated that both the

astrogliosis and microgliosis were strongly correlated with the increased

fibrillar Aß deposits. Conclusions: GRK5 deficiency promotes ß-amyloi-

dogenic ßAPP processing, which leads to accelerated Aß accumulation

and deposition; and the increased fibrillar Aß deposits further cause the

exaggerated brain astrogliosis and microgliosis in the GRK5KO/APPsw

mice.

P4-163 ROLE OF THE BDNF VAL66MET

POLYMORPHISM IN HIPPOCAMPAL SYNAPTIC

PLASTICITY

Ipe Ninan1, Karishma Dagar2, Rosalia Perez-Castro2, Mark R. Plummer3,

Francis S. Lee4, Moses V. Chao2, 1Department of Psychiatry, NYU School of

Medicine, New York, NY, USA; 2Skirball Institute, NYU School of Medicine,

New York, NY, USA; 3Department of Cell Biology and Neuroscience,

Rutgers University, New Jersey, NJ, USA; 4Department of Psychiatry, Weill

Medical College of Cornell University, New York, NY, USA.

Contact e-mail: Ipe.Ninan@nyumc.org.

Background: The Val66Met polymorphism in the Brain-Derived Neurotro-

phic Factor (BDNF) gene has been recently linked to Alzheimer’s disease.

Also, the BDNF Val66Met polymorphism affects episodic memory and af-

fective behaviors, and results in a defect in regulated release of BDNF.

Methods: Given the purported role of hippocampal synaptic plasticity in

memory, we examined synaptic neurotransmission and plasticity in the hip-

pocampal CA3-CA1 synapses of BDNFMet/Met mice. Results: Although

basal synaptic neurotransmission was normal, both young and adult mice

had shown significant impairment of long-term potentiation which was

NMDA receptor-dependent. We also found that NMDA receptor-dependent

long-term depression was impaired in the BDNFMet/Met mice. However,

mGluR-dependent long-term depression was normal in the BDNFMet/

Met mice. Consistent with the NMDA receptor-dependent synaptic plastic-

ity impairment, we observed a significant decrease in NMDA receptor neu-

rotransmission in the CA1 pyramidal neurons of BDNFMet/Met mice.

Conclusions: Thus, the BDNF Val66Met polymorphism causes an impair-

ment of NMDA receptor neurotransmission and synaptic plasticity in the

hippocampus. The effect of BDNF Val66Met polymorphism on hippocam-

pal synaptic plasticity might play a role in cognitive dysfunction in

Alzheimer’s disease.