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Correlation Between Ax-40–, Ax-42–, and Ax-43–Containing Amyloid Plaques and Cognitive Decline

S. Parvathy, PhD; Peter Davies, PhD; Vahram Haroutunian, PhD; Dushyant P. Purohit, MD; Kenneth L. Davis, MD; Richard C. Mohs, PhD; Helen Park; Thomas M. Moran, PhD; Joseph Y. Chan, MS; Joseph D. Buxbaum, PhD

Arch Neurol. 2001;58:2025-2031.

ABSTRACT
Context  Accumulation of senile plaques containing amyloid (A)-protein is a pathologic hallmark of Alzheimer disease. Amyloid -peptide is heterogeneous, with carboxyterminal variants ending at residues Val40 (Ax-40), Ala42 (Ax-42), or Thr43 (Ax-43). The relative importance of each of these variants in dementia or cognitive decline remains unclear.

Objective  To study whether A deposition correlates with dementia and occurs at the earliest signs of cognitive decline.

Design, Setting, and Patients  Postmortem cross-sectional study comparing the deposition of A variants in the prefrontal cortex of 79 nursing home residents having no, questionable, mild, moderate, or severe dementia.

Main Outcome Measures  Levels of staining of A-peptides ending at amino acid 40, 42, or 43 in the frontal cortex, as a function of Clinical Dementia Rating score.

Results  There were significant deposits of all 3 A species that strongly correlated with cognitive decline. Furthermore, deposition of Ax-42 and Ax-43 occurred very early in the disease process before there could be a diagnosis of Alzheimer disease. Levels of deposited Ax-43 appeared surprisingly high given the low amounts synthesized.

Conclusions  These data indicate that Ax-42 and Ax-43 are important species associated with early disease progression and suggest that the physiochemical properties of the A species may be a major determinant in amyloid deposition. The results support an important role for A in mediating initial pathogenic events in Alzheimer disease dementia and reinforce that treatment strategies targeting the formation, accumulation, or cytotoxic effects of A should be pursued.

INTRODUCTION

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ALZHEIMER disease (AD) is characterized histopathologically by the intraneuronal accumulation of paired helical filaments composed of abnormal proteins and extracellular deposits of an amyloid (A)-peptide in plaques.^1-2 Amyloid is proteolytically derived from a large integral membrane protein, the amyloid precursor protein (APP). Amyloid precursor protein can be processed by at least 3 secretases, namely, -, -, and secretases. -Secretase initiates A generation by cleaving APP after methionine 671 (using APP770 numbering), creating an approximate 12-kd–membrane retained carboxy terminal fragment.³ The 12-kd fragment may then undergo -secretase cleavage within the hydrophobic transmembrane domain at valine 710, alanine 712, or threonine 713 to release the 40, 42, or 43 residue A-peptides, respectively.⁴ Four groups have recently identified a candidate for -secretase, known as BACE (for -site APP-cleaving enzyme).^5-8 There has been increasing evidence that presenilin might be a functional -secretase or it might act as a cofactor for -secretase.^9-10 Both -secretase and -secretase are targets for drug discovery.

Immunocytochemical studies using antibodies against A have established that A is deposited in cored plaques, which include well-defined amyloid cores, and in diffuse plaques, which are poorly circumscribed immunoreactive lesions showing minimal neuritic change.^11-12 Different A species have been identified in the AD-affected brain. Mass spectrometric studies on A derived from AD-affected brains identified that the carboxy terminal of A typically ends at residues 40, 42, or 43.^13-14 In vitro experiments have clearly demonstrated that Ax-42 and Ax-43 polymerize faster than Ax-40, suggesting that the carboxy terminal of A determines the aggregation potential, and therefore, is one of the critical determinants for the rate of amyloid fibril formation.^15-16 Virtually all antibodies that have been developed to measure Ax-42 do not distinguish between A ending at residue 42 or 43.^17-21 In addition, to our knowledge, there has been only 1 report in which an antibody specific for A ending at residue 43 was used to examine cases of AD.²² Therefore, the role of the various A species in dementia, and particularly early dementia, are not fully understood.

Furthermore, it has been controversial whether amyloid plaques per se are, in fact, correlated with AD. In several early studies it has been argued that, in fact, amyloid plaques do not correlate with AD^23-25; however, in recent studies correlations have been observed.^26-27 The relative role for plaques containing Ax-40, Ax-42, or Ax-43 in disease progression has not been studied in detail.

In the current study we have developed antibodies that specifically recognized A ending at position 40 (Ax-40), 42 (Ax-42), or 43 (Ax-43) with no cross reactivity. The pattern of plaque staining with Ax-40, Ax-42, and Ax-43 antibodies in the frontal cortex of 79 individuals with varying degrees of dementia was studied.

SUBJECTS, MATERIALS, AND METHODS

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SUBJECTS

Seventy-nine subjects who had been residents of the Jewish Home and Hospital in Manhattan and the Bronx, NY, were included in the study. These subjects were selected from a larger group of 278 consecutive autopsies performed between November 11, 1986, and April 27, 1997, after excluding patients with neuropathologic lesions other than those of AD (eg, lesions of Pick disease, diffuse Lewy body disease, Parkinson disease, stroke, multi-infarct dementia, and severe cerebrovascular disease). A multistep approach was used to assign Clinical Dementia Rating (CDR) scores based on cognitive and functional status during the last 6 months of life. A consensus CDR score was obtained following a careful review of all information contained within each patient's medical record, including admitting diagnosis, nurses' notes, social work records, results of psychiatric and neurologic consultations, medication histories, results of mental status testing, and results of laboratory studies. The methods used for subject selection and cognitive and neuropathologic assessment have been described previously in detail.^{26, 28-29} Because one of our aims was to identify whether there is a relationship between amyloid plaque deposition and clinical dementia, 5 groups of subjects were formed, consisting of cases falling into CDR score categories of 0.0 (no dementia), 0.5 (questionable dementia), 1.0 (mild dementia), 2.0 (moderate dementia), and 4.0 or 5.0 (severe or terminal dementia). The demographic data for the final selection of the subjects is given in Table 1. Twenty of the subjects had 1 apolipoprotein E allele of the 4 type and 4 subjects had 2. The cases with 1 allele were evenly distributed within the CDR groups. Of those 4 cases with 2 alleles, 1 case was classified as CDR 0.0; 1, CDR 1.0; and 2, CDR 5.0.

View this table: [in this window] [in a new window] Table 1. Demographic Characteristics of Subjects

PREPARATION OF MONOCLONAL ANTIBODIES

The carboxy terminal–specific antibodies were prepared by injecting mice with the peptides corresponding to the last 6 amino acids of Ax-40, Ax-42, or Ax-43, which had been coupled to keyhole limpet hemocyanin through the addition of an amino-terminal cysteine. Hybridomas that tested positive by enzyme-linked immunosorbent assay (ELISA) were then further characterized as detailed in the "Results" section. The Ax-40–, Ax-42–, and Ax-43–specific antibodies were identified as AC40, AC42, and AC43, respectively.

IMMUNOHISTOCHEMISTRY

Immunostaining was performed in sections of frontal cortex (5 µm) that were cut from paraffin-embedded tissue blocks, deparaffinized with xylene, and rehydrated using 100%, 95%, and 80% ethanol. Following rehydration, the endogenous horseradish-peroxidase activity was quenched by incubating in hydrogen peroxide, and formic acid was used to enhance immunoreactivity. Sections were blocked for 1 hour at room temperature in blocking buffer (5% nonfat milk in 10mM Tris, 140mM sodium chloride [NaCl], pH 7.4), followed by an overnight incubation with primary antibody (anti–ABx40 [AC40] at a dilution of 1:250, anti–ABx-42 [AC42] at at a dilution of 1:2000, and anti–ABx-43 [AC43] at a dilution of 1:500) at 4°C in blocking solution. Sections were washed 5 times in Tris-buffered saline (10mM Tris, 140mM NaCl, pH 7.4), incubated in secondary antibody (biotin-conjugated, isotype-specific goat anti–mouse IgG1 or IgG2B at 1:500 dilution; Southern Biotechnology Associates, Birmingham, Ala) for 2 hours, washed again, and incubated with streptavidine conjugated–horseradish-peroxidase for 1 hour at room temperature. After reaction with substrate (diaminobenzidine) (0.3 mg/mL in 100mM Tris, pH 7.4 with 0.01% hydrogen peroxide), slides were washed for 5 minutes in Tris-buffered saline, dehydrated in 80%, 95%,100% ethanol and xylene, and counterstained with toluidine blue and cover slipped using synthetic mounting medium (Permount; Fisher Scientific, Morris Plains, NJ).

For double labeling, AC42 was used with alkaline phosphatase conjugated goat anti–mouse IgG2B (Southern Biotechnology Associates) and the substrate nitroblue tetrazolium chloride (Pierce Chemical Co, Rockford, Ill) for 1 hour at room temperature for blue color development. In addition, the dehydration step did not include xylene, and counterstaining with toluidine blue was excluded.

IMMUNOELECTROPHORETIC BLOT

Synthetic A1-40, A1-42, and A1-43 (1 µg) were resolved on a 10% to 20% Tris-tricine gel in running buffer (100mM Tris, 100mM tricine, 0.1% sodium dodecyl sulfate, pH 7.4) and transferred to a polyvinylidene difluoride membrane using transfer buffer (20mM Tris, 120mM glycine, 20% methanol) at 30 mA for 1 hour. The polyvinylidene difluoride membrane was blocked in blocking solution (50mM Tris, 150mM NaCl, 0.05% polysorbate [Tween] 20, pH 8.0 containing 5% milk) for 3 hours at room temperature and probed overnight at 4°C with AC40, AC42, or AC43 at a 1:1000 dilution, followed by 1-hour incubation with peroxidase conjugated anti–mouse antibody at a 1:2000 dilution. Bound antibody was detected using enhanced chemiluminescent system (Amersham Pharmacia Biotech, Piscataway, NJ).

ENZYME-LINKED IMMUNOSORBENT ASSAY

Microtiter plates were coated with the respective synthetic peptides in carbonate-bicarbonate (50mM) buffer, pH 9.6, at amounts ranging from 0 to 1000 ng per well and incubated for 18 hours at 37°C. After blocking with ELISA coupling and wash buffer (phosphate-buffered saline, 0.1% bovine serum albumin, 0.05% polysorbate 20, 0.2% 3-(cyclohexylamino)-1-propanesulphonic acid, 5mM EDTA, 2mM betaine, 0.05% sodium azide) containing 1% casein for 4 hours at room temperature, wells were incubated with antibody at 1 µg/mL for 15 hours. Following washing with ELISA coupling and wash buffer, wells were incubated for 5 hours at room temperature with goat anti–mouse antibody conjugated with biotin, followed by an incubation with streptavidine conjugated–alkaline phosphatase. The substrate AttoPhos (Promega, San Luis Obispo, Calif) was used to generate the fluorescent product.

QUANTIFICATION OF AMYLOID LOAD

Two methods for quantifying amyloid load were used. For cored plaques, the area of cortex occupied by amyloid was determined in a blinded fashion using semiautomated, quantitative computer analysis as previously documented.³⁰ For each case images from 5 different fields were captured and analyzed. For diffuse plaques, this method could not be reliably used. Instead, the extent of diffuse plaque staining was categorized into 1 of 4 levels (0-3, with 0 reflecting no plaques). To determine the accuracy of this semiquantitative approach, 25 cases (5 cases from each CDR group) were evaluated for cored plaques using both the semiautomated quantitative computer analysis and the semiquantitative approach, and the results compared. In these analyses, the quantitative values correlated well with the semiquantitative rating (r values were 0.81 for AC40, 0.89 for AC42, and 0.75 for AC43).

In 12 cases (3 with a CDR 0.0 score, 2 with a CDR 0.5 score, 3 with a CDR 1.0 score, 1 with a CDR 2.0 score, and 3 with CDR score 4.0 or 5.0) that were double labeled for Ax-40 and Ax-42 or Ax-42 and Ax-43, 4 areas were quantified for the number of Ax-40–, Ax-42–, and Ax-43–containing diffuse and cored plaques.

DATA ANALYSIS

Diffuse and cored amyloid plaque load detected by each of the carboxy terminal–specific antibodies was used as the independent variables for subsequent analyses. The dependent variable consisted of 5 CDR categories. For further exploratory analyses, quantitative plaque counts measured by silver staining, soluble A levels, and phosphorylated levels determined by ELISA were used as dependent variables. Spearman rank order correlation was used to calculate the P values. Statistical significance was set at P<.05.

RESULTS

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CHARACTERIZATION OF CARBOXY TERMINAL– SPECIFIC ANTI-A ANTIBODIES

Three monoclonal antibodies that specifically detected the different carboxy terminal ends of A-peptide were developed and characterized. The carboxy terminal–specific antibodies were named AC40, AC42, and AC43, recognizing the carboxy terminal of Ax-40, Ax-42, and Ax-43, respectively. The specificity and cross reactivity of the 3 antibodies were examined using dot blots, immunoblotting, and ELISA (Figure 1). Each antibody was specific for the corresponding peptide to which it was prepared.

View larger version (32K): [in this window] [in a new window] Figure 1. Characterization of antibodies. AC40, AC42, and AC43 are antibodies reactive to amyloid x-40. Specificity of antibodies AC40 (anti-Ax-40), AC42 (anti-Ax-42), and AC43 (anti-Ax-43) was determined by dot blotting (A), immunoblotting (B), and enzyme-linked immunosorbent assay (C). Synthetic A1-40, A1-42, or A1-43, was either spotted on a nitrocellulose membrane (A) or electrophoresed on a Tris-tricine gel and transferred to a nitrocellulose membrane (B). The membranes were probed with the indicated antibodies and detected using horseradish peroxidase–conjugated secondary antibody with enhanced chemiluminescent reagent. In part C indicated amounts of A1-40, A1-42, and A1-43 peptides were coated onto enzyme-linked immunosorbent assay plates and incubated with antibody. Bound antibody was detected using a calorimetric assay.

IMMUNOCYTOCHEMISTRY OF FRONTAL CORTEX

Frontal cortical sections (Brodmann area 9) of controls and cases with AD were immunostained with the antibodies; the bound antibody was detected using diaminobenzidine substrate. Typical staining patterns of subjects with a CDR 0.0 and 5.0 scores are shown in Figure 2. We distinguished between 2 types of plaques—cored, which have an intensely stained central core with a weakly stained peripheral (halo) region, and diffuse, which do not have a core and the immunoreactivity is uniform over the plaque. AC40 and AC42 labeled both cores and the plaque periphery of cored plaques as well as diffuse plaques. AC43 also labeled both diffuse and cored plaques. However, in cored plaques, we noted that AC43 essentially only labeled what appeared to be the plaque core, with little or no Ax-43 reactivity in the halos of the cored plaques.

View larger version (36K): [in this window] [in a new window] Figure 2. Immunocytochemical analysis of amyloid plaques. Sections (5 µm) of frontal cortex from subjects with Clinical Dementia Rating (CDR) scores 0.0 and 5.0 (for explanation of the scores, see "Subjects" subsection of the "Subjects, Materials, and Method" section) were incubated with the indicated antibodies as described in "Methods" subsection of the "Subjects, Materials, and Method" section (original magnification x6). White arrows indicate diffuse plaques; black arrows, cored plaques. AC40, AC42, and A43 are antibodies reactive to amyloid x-40.

DOUBLE LABELING OF PLAQUE TYPES

To determine whether the plaques identified by each of these antibodies were the same or different, double labeling with AC42 and AC40 (Figure 3A-C) or with AC42 and AC43 (Figure 3D-F) was carried out. Because the isotypes of AC40 and AC43 were identical, double labeling could not be performed with this pair of antibodies. Conditions were developed so that reactivity with AC42 antibody generated a blue product while reactivity with AC40 or AC43 generated a brown product. When double labeling for Ax-40 and Ax-42, most deposits were blue, representing Ax-42. Some deposits were brown, representing Ax-40, while others were purple, indicating colocalization of both Ax-40 and Ax-42.

View larger version (51K): [in this window] [in a new window] Figure 3. Double-labeling of amyloid plaques. Frontal cortex sections of a subject with a Clinical Dementia Rating score of 5.0 (severe or terminal dementia) were incubated with the indicated antibodies and developed using a secondary system that labeled Ax-42 in blue and Ax-40 and Ax-43 in brown (original magnification x13 or x26, respectively). With AC40 and AC42 staining (A through C), we observed plaques reactive for Ax-42 (blue), plaques reactive for only Ax-40 (black arrows), and plaques showing colocalization (white arrows). With AC42 and AC43 staining (D through F), we observed plaques reactive for Ax-42 (blue) and plaques showing colocalization (white arrows). AC40, AC42, and AC43 are antibodies reactive to amyloid x-40.

When double labeling for Ax-42 and Ax-43, most deposits were blue, ie, were composed of Ax-42. Some cored plaques were very intensely stained purple in the core of the plaque, representing colocalization of Ax-42 and Ax-43. Diffuse plaques were either exclusively blue (Ax-42) or purple (Ax-42 andAx-43). No plaques were stained only brown, indicating all Ax-43 plaques contain Ax-42. In addition, no cored plaques demonstrated significant Ax-43 reactivity outside of the core (Figure 3).

CORRELATION OF AMYLOID PLAQUE DEPOSITION WITH DEMENTIA

Immunostaining was carried out in 79 patients with varying degrees of dementia. The subjects chosen for this study were classified according to their CDR scores; the demographic characteristics of the subjects are given in Table 1. The cohort included subjects without dementia (CDR score 0.0 [n = 16]), those with questionable dementia (CDR score 0.5 [n = 11]), those with mild dementia (CDR score 1.0 [n = 22]), those with moderate dementia (CDR score 2.0 [n = 15), and those with severe dementia (CDR score 4.0 or 5.0 [n = 15]). Amyloid load was determined in the sections of frontal cortex of these cases for both cored and diffuse plaques. Amyloid load for each antibody as a function of CDR scores is shown in Figure 4. With all 3 antibodies there was a strong correlation between CDR scores and cored plaques (Table 2). In the case of diffuse plaques, levels of Ax-42 and Ax-43 plaques correlated with dementia while levels of Ax-40 did not. The lack of correlation of diffuse Ax-40 plaques is not surprising given that levels of these plaques remain relatively unchanged across CDR scores.

View larger version (23K): [in this window] [in a new window] Figure 4. Amyloid load as a function of Clinical Dementia Rating (CDR) score where 0.0 indicates no dementia; 0.5, questionable dementia; 1.0, mild dementia; 2.0, moderated dementia; and 4.0 and 5.0, severe or terminal dementia. Sections were incubated with each of the carboxy terminal-specific antibodies and the bound antibodies were detected using horseradish peroxidase-conjugates and diaminobenzidine substrate. Sections were counterstained with toluidine blue and the amyloid load was determined. Average (±SEM) scores were plotted against the CDR scores. AC40, AC42, and AC43 are antibodies reactive to amyloid x-40.

View this table: [in this window] [in a new window] Table 2. Correlation Between Clinical Dementia Rating (CDR) Score and Amyloid Plaque Load

In further analysis, correlations were determined for a subset of CDR scores (ie, 0.0-2.0 and 0.5-5.0) (Table 2). The purpose of these analyses was to determine to what degree the correlations observed for amyloid load with CDR score were driven by changes in the extreme CDR groups. In these analyses it was clear that for Ax-42 and Ax-43 the correlations observed for CDR 0.0-5.0 were not driven exclusively by changes between controls and cases with dementia or between cases with severe dementia and the rest of the cohort.

RELATIVE LEVELS OF PLAQUE TYPES DURING DISEASE PROGRESSION

The proportion of cored and diffuse plaques containing Ax-40, Ax-42, or Ax-43 was determined from double-labeled sections. Twelve cases were stained for Ax-40 and Ax-42 or Ax-42 and Ax-43, and the number of cored and diffuse plaques stained for 1 or both antibodies counted in 4 regions. Levels of Ax-42–reactive plaques were highest (Figure 5), representing more than 50% of the total plaques in both labeling conditions. However, significant levels of Ax-40– and particularly Ax-43–reactive plaques were observed as well. All Ax-43–containing and most of the Ax-40–containing plaques also contained Ax-42.

View larger version (16K): [in this window] [in a new window] Figure 5. Relative proportion of amyloid (A) plaque types. The number of cored and diffuse plaques in double-labeled sections stained for either AC40 and AC42 (A) or AC42 and AC43 (B) antibodies was determined and is given as a percentage of total plaques counted in each condition. In each condition, the number of plaques containing either 1 or 2 A variants was determined. AC40, AC42, and AC43 are antibodies reactive to Ax-40.

CORRELATION OF AMYLOID PLAQUE DEPOSITION WITH OTHER MARKERS OF DISEASE

In further exploratory analyses, Spearman rank order correlation was performed to find the correlation between amyloid plaque load and silver-stained plaques, soluble A levels, or phosphorylated levels. Amyloid load in the frontal cortex correlated with the level of plaques²⁶ determined by silver staining (r ranging from 0.3889-0.6254; P<.001 in all cases). Soluble A levels measured in the same region by ELISA³¹ correlated with the levels of both diffuse and cored plaques (Table 3), with Ax-40–containing diffuse plaques correlating apparently less well. There was also a correlation between the diffuse and cored plaques and the amount of phosphorylated in the frontal cortex measured by the phospho-state–specific antibody MC1 using ELISA,³¹ but again correlation with diffuse Ax-40 plaques was apparently lower (Table 4).

View this table: [in this window] [in a new window] Table 3. Correlation Between Soluble A and Amyloid Plaque Load*

View this table: [in this window] [in a new window] Table 4. Correlation Between Amyloid Plaque Load and Phosphorylation

COMMENT

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In the current study we have developed specific antibodies for Ax-40, Ax-42, and Ax-43. Staining with these antibodies identified diffuse and cored plaques reacting with each of these antibodies. The level of diffuse Ax-42– and Ax-43–containing plaques increased with increasing disease severity while the levels of diffuse Ax-40–containing plaques did not. Levels of cored Ax-40–, Ax-42–, and Ax-43–containing plaques increased with disease severity, but there were no cored Ax-40–containing plaques in early dementia (the areas shown in Figure 4 represent background). Plaque levels correlated with dementia, plaque load determined by silver staining, and the levels of total A and phosphorylated as measured by ELISA. Note that the number of subjects with 1 or 2 apolipoprotein E alleles of the type 4 were too small for any reliable analysis by apolipoprotein E allele genotype.

With double labeling it appears that there are Ax-40–containing plaques that do not contain Ax-42. In addition, there appear to be Ax-42–containing plaques that contain neither Ax-40 nor Ax-43. There are plaques containing both Ax-40 and Ax-42 as well as plaques containing both Ax-42 and Ax-43. We did not detect any Ax-43–containing plaques that were not reactive for Ax-42. By the careful examination of double-labeled sections, we were able to estimate the relative amount of each of the plaque species. Approximately 20% of the plaques were reactive for Ax-40 and 20% of the plaques were reactive for Ax-43. From a great number of studies with cells in culture, it appears that Ax-40 is the most common species synthesized, with low levels of Ax-42 and even lower levels of Ax-43.^32-36 These ratios appear to be true in vivo as well.^{14, 36} The accumulation of large amounts of Ax-42–containing plaques and significant levels of Ax-43–containing plaques appear to be disproportionate to the levels of synthesis of these variants. This suggests that factors aside from the level synthesized are critical for accumulation. One such factor could be the physiochemical properties of the peptides and the increased propensity for the larger variants to aggregate.

CONCLUSIONS

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In the current study we show that there is significant deposition of all A species that strongly correlate with cognitive decline. In addition, our studies show the correlation of Ax-43 deposition with dementia in a very large cohort. Furthermore, deposition, particularly of Ax-42 and Ax-43, occurs very early in the disease process even before there is a diagnosis of AD. These data also suggest that the physiochemical properties of the A species are a major determinant in amyloid deposition. Altogether, these data support A accumulation as an important component of disease progression and suggest that reducing A levels in the brain may be beneficial in AD.

AUTHOR INFORMATION

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Accepted for publication August 17, 2001.

This work was supported by grants AG02219 (Drs Haroutunian, Davis, Mohs, and Buxbaum) and AG10491 (Dr Buxbaum) from the National Institute on Aging, National Institutes of Health, Bethesda, Md.

Corresponding author: Joseph D. Buxbaum, PhD, Laboratory of Molecular Neuropsychiatry, Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1230, New York, NY 10029 (e-mail: buxbaj01{at}doc.mssm.edu).

From the Laboratory of Molecular Neuropsychiatry (Drs Parvathy and Buxbaum and Mr Chan), Departments of Psychiatry (Drs Parrathy, Haroutunian, Davis, Mohs, and Buxbaum and Mr Chan), Pathology (Dr Purohit), Microbiology (Dr Moran), and Neurobiology (Dr Buxbaum), and The Hybridoma Core Facility (Ms Park), Mount Sinai School of Medicine, New York, NY; and the Departments of Pathology and Neuroscience (Dr Davies), Albert Einstein College of Medicine, Bronx, NY.

REFERENCES

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1. Spillantini MG, Goedert M, Jakes R, Klug A. Different configurational states of -amyloid and their distributions relative to plaques and tangles in Alzheimer disease. Proc Natl Acad Sci U S A. 1990;87:3947-3951. FREE FULL TEXT 2. Glenner GG, Wong CW. Alzheimer's disease: initial report of the purification and characterization of a novel cerebrovascular amyloid protein. Biochem Biophys Res Commun. 1984;120:885-890. FULL TEXT | ISI | PUBMED 3. Citron M, Teplow DB, Selkoe DJ. Generation of amyloid protein from its precursor is sequence specific. Neuron. 1995;14:661-670. FULL TEXT | ISI | PUBMED 4. Seubert P, Vigo-Pelfrey C, Esch F, et al. Isolation and quantification of soluble Alzheimer's -peptide from biological fluids. Nature. 1992;359:325-327. FULL TEXT | PUBMED 5. Hussain I, Powell D, Howlett DR, et al. Identification of a novel aspartic protease (Asp 2) as -secretase. Mol Cell Neurosci. 1999;14:419-427. FULL TEXT | ISI | PUBMED 6. Sinha S, Anderson JP, Barbour R, et al. Purification and cloning of amyloid precursor protein -secretase from human brain. Nature. 1999;402:537-540. FULL TEXT | PUBMED 7. Vassar R, Bennett BD, Babu-Khan S, et al. -Secretase cleavage of Alzheimer's amyloid precursor protein by the transmembrane aspartic protease BACE. Science. 1999;286:735-741. FREE FULL TEXT 8. Yan R, Bienkowski MJ, Shuck ME, et al. Membrane-anchored aspartyl protease with Alzheimer's disease -secretase activity. Nature. 1999;402:533-537. FULL TEXT | PUBMED 9. Li YM, Lai MT, Xu M, et al. Presenilin 1 is linked with -secretase activity in the detergent solubilized state. Proc Natl Acad Sci U S A. 2000;97:6138-6143. FREE FULL TEXT 10. Xia W, Ray WJ, Ostaszewski BL, et al. Presenilin complexes with the C-terminal fragments of amyloid precursor protein at the sites of amyloid -protein generation. Proc Natl Acad Sci U S A. 2000;97:9299-9304. FREE FULL TEXT 11. Yamaguchi H, Hirai S, Morimatsu M, Shoji M, Ihara Y. A variety of cerebral amyloid deposits in the brains of the Alzheimer-type dementia demonstrated by protein immunostaining. Acta Neuropathol (Berl). 1988;76:541-549. FULL TEXT | PUBMED 12. Masliah E, Terry RD, Mallory M, Alford M, Hansen LA. Diffuse plaques do not accentuate synapse loss in Alzheimer's disease. Am J Pathol. 1990;137:1293-1297. ABSTRACT 13. Miller DL, Papayannopoulos IA, Styles J, et al. Peptide compositions of the cerebrovascular and senile plaque core amyloid deposits of Alzheimer's disease. Arch Biochem Biophys. 1993;301:41-52. FULL TEXT | ISI | PUBMED 14. Mori H, Takio K, Ogawara M, Selkoe DJ. Mass spectrometry of purified amyloid protein in Alzheimer's disease. J Biol Chem. 1992;267:17082-17086. FREE FULL TEXT 15. Jarrett JT, Berger EP, Lansbury, PT Jr. The carboxy terminus of the -amyloid protein is critical for the seeding of amyloid formation: implications for the pathogenesis of Alzheimer's disease. Biochemistry. 1993;32:4693-4697. FULL TEXT | PUBMED 16. Jarrett JT, Berger EP, Lansbury, PT Jr. The C-terminus of the protein is critical in amyloidogenesis [review]. Ann N Y Acad Sci. 1993;695:144-148. ISI | PUBMED 17. Gravina SA, Ho L, Eckman CB, et al. Amyloid -protein (A) in Alzheimer's disease brain: biochemical and immunocytochemical analysis with antibodies specific for forms ending at A40 or A42(43). J Biol Chem. 1995;270:7013-7016. FREE FULL TEXT 18. Fukumoto H, Asami-Odaka A, Suzuki N, et al. Amyloid -protein deposition in normal aging has the same characteristics as that in Alzheimer's disease: predominance of A42(43) and association of A40 with cored plaques. Am J Pathol. 1996;148:259-265. ABSTRACT 19. Iwatsubo T, Odaka A, Suzuki N, Mizusawa H, Nukina N, Ihara Y. Visualization of A42(43) and A40 in senile plaques with end-specific A monoclonals: evidence that an initially deposited species is A42(43). Neuron. 1994;13:45-53. FULL TEXT | ISI | PUBMED 20. Mann DM, Iwatsubo T, Ihara Y, et al. Predominant deposition of amyloid-42(43) in plaques in cases of Alzheimer's disease and hereditary cerebral hemorrhage associated with mutations in the amyloid precursor protein gene. Am J Pathol. 1996;148:1257-1266. ABSTRACT 21. Tamaoka A, Sawamura N, Odaka A, et al. Amyloid -protein 1-42/43 (A-1-42/43) in cerebellar diffuse plaques: enzyme-linked immunosorbent assay and immunocytochemical study. Brain Res. 1995;679:151-156. FULL TEXT | ISI | PUBMED 22. Iizuka T, Shoji M, Harigaya Y, et al. Amyloid -protein ending at Thr43 is a minor component of some diffuse plaques in the Alzheimer's disease brain, but is not found in cerebrovascular amyloid. Brain Res. 1995;702:275-278. FULL TEXT | ISI | PUBMED 23. Lassmann H, Fischer P, Jellinger K. Synaptic pathology of Alzheimer's disease [review]. Ann N Y Acad Sci. 1993;695:59-64. ISI | PUBMED 24. Arriagada PV, Growdon JH, Hedley-Whyte ET, Hyman BT. Neurofibrillary tangles but not senile plaques parallel duration and severity of Alzheimer's disease. Neurology. 1992;42(pt 1):631-639. 25. Samuel W, Terry RD, DeTeresa R, Butters N, Masliah E. Clinical correlates of cortical and nucleus basalis pathology in Alzheimer dementia. Arch Neurol. 1994;51:772-778. FREE FULL TEXT 26. Haroutunian V, Perl DP, Purohit DP, et al. Regional distribution of neuritic plaques in the nondemented elderly and subjects with very mild Alzheimer disease. Arch Neurol. 1998;55:1185-1191. FREE FULL TEXT 27. Cummings BJ, Pike CJ, Shankle R, Cotman CW. -Amyloid deposition and other measures of neuropathology predict cognitive status in Alzheimer's disease. Neurobiol Aging. 1996;17:921-933. FULL TEXT | ISI | PUBMED 28. Davis KL, Mohs RC, Marin D, et al. Cholinergic markers in elderly patients with early signs of Alzheimer disease. JAMA. 1999;281:1401-1406. FREE FULL TEXT 29. Haroutunian V, Purohit DP, Perl DP, et al. Neurofibrillary tangles in nondemented elderly subjects and mild Alzheimer disease. Arch Neurol. 1999;56:713-718. FREE FULL TEXT 30. Hyman BT, Marzloff K, Arriagada PV. The lack of accumulation of senile plaques or amyloid burden in Alzheimer's disease suggests a dynamic balance between amyloid deposition and resolution. J Neuropathol Exp Neurol. 1993;52:594-600. ISI | PUBMED 31. Naslund J, Haroutunian V, Mohs R, et al. Correlation between elevated levels of amyloid beta-peptide in the brain and cognitive decline. JAMA. 2000;283:1571-1577. FREE FULL TEXT 32. Haass C, Schlossmacher MG, Hung AY, et al. Amyloid -peptide is produced by cultured cells during normal metabolism. Nature. 1992;359:322-325. FULL TEXT | PUBMED 33. Suzuki N, Cheung TT, Cai XD, et al. An increased percentage of long amyloid protein secreted by familial amyloid -protein precursor ( APP717) mutants. Science. 1994;264:1336-1340. FREE FULL TEXT 34. Yamazaki T, Haass C, Saido TC, Omura S, Ihara Y. Specific increase in amyloid -protein 42 secretion ratio by calpain inhibition. Biochemistry. 1997;36:8377-8383. FULL TEXT | PUBMED 35. Wang R, Sweeney D, Gandy SE, Sisodia SS. The profile of soluble amyloid protein in cultured cell media: detection and quantification of amyloid -protein and variants by immunoprecipitation-mass spectrometry. J Biol Chem. 1996;271:31894-31902. FREE FULL TEXT 36. Tamaoka A, Odaka A, Ishibashi Y, et al. APP717 missense mutation affects the ratio of amyloid -protein species (A-1-42/43 and A-1-40) in familial Alzheimer's disease brain. J Biol Chem. 1994;269:32721-32724. FREE FULL TEXT

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