Claudio Russo

The amyloid beta protein precursor (AbetaPP) is sequentially processed by beta- and gamma-secretases to generate the Abeta peptide. The biochemical path leading to Abeta formation has been extensively studied since extracellular aggregates of amyloidogenic forms of Abeta peptide (Abeta42) are considered the culprit of Alzheimer's disease. Aside from its pathological relevance, the biological role of AbetaPP proteolysis is unknown. Although never previously described, cleavage of AbetaPP by gamma-secretase should release, together with Abeta, a COOH-terminal AbetaPP Intracellular Domain, herein termed AID. We have now identified AID-like peptides in brain tissue of normal control and patients with sporadic Alzheimer's disease and demonstrate that AID acts as a positive regulator of apoptosis. Thus, overproduction of AID may add to the toxic effect of Abeta42 aggregates and further accelerate neurodegeneration.

N-terminally truncated amyloid-beta (Abeta) peptides are present in early and diffuse plaques of individuals with Alzheimer's disease (AD), are overproduced in early onset familial AD and their amount seems to be directly correlated to the severity and the progression of the disease in AD and Down's syndrome (DS). The pyroglutamate-containing isoforms at position 3 [AbetaN3(pE)-40/42] represent the prominent form among the N-truncated species, and may account for more than 50% of Abeta accumulated in plaques. In this study, we compared the toxic properties, fibrillogenic capabilities, and in vitro degradation profile of Abeta1-40, Abeta1-42, AbetaN3(pE)-40 and AbetaN3(pE)-42. Our data show that fibre morphology of Abeta peptides is greatly influenced by the C-terminus while toxicity, interaction with cell membranes and degradation are influenced by the N-terminus. AbetaN3(pE)-40 induced significantly more cell loss than the other species both in neuronal and glial cell cultures. Aggregated AbetaN3(pE) peptides were heavily distributed on plasma membrane and within the cytoplasm of treated cells. AbetaN3(pE)-40/42 peptides showed a significant resistance to degradation by cultured astrocytes, while full-length peptides resulted partially degraded. These findings suggest that formation of N-terminally modified peptides may enhance beta-amyloid aggregation and toxicity, likely worsening the onset and progression of the disease.

The mechanism of neurodegeneration caused by β-amyloid in Alzheimer disease is controversial. Neuronal toxicity is exerted mostly by various species of soluble β-amyloid oligomers that differ in their N- and C-terminal domains. However, abundant accumulation of β-amyloid also occurs in the brains of cognitively normal elderly people, in the absence of obvious neuronal dysfunction. We postulated that neuronal toxicity depends on the molecular composition, rather than the amount, of the soluble β-amyloid oligomers. Here we show that soluble β-amyloid aggregates that accumulate in Alzheimer disease are different from those of normal aging in regard to the composition as well as the aggregation and toxicity properties. The mechanism of neurodegeneration caused by β-amyloid in Alzheimer disease is controversial. Neuronal toxicity is exerted mostly by various species of soluble β-amyloid oligomers that differ in their N- and C-terminal domains. However, abundant accumulation of β-amyloid also occurs in the brains of cognitively normal elderly people, in the absence of obvious neuronal dysfunction. We postulated that neuronal toxicity depends on the molecular composition, rather than the amount, of the soluble β-amyloid oligomers. Here we show that soluble β-amyloid aggregates that accumulate in Alzheimer disease are different from those of normal aging in regard to the composition as well as the aggregation and toxicity properties. A series of evidence indicates that progressive cerebral accumulation of β-amyloid (Aβ) 2The abbreviations used are: Aβ, β-amyloid; AD, Alzheimer disease; APP, β-amyloid precursor protein; NA, normal aging (cognitively normal elderly subjects); AFM, atomic force microscopy; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; MALDI-TOF, matrix-assisted laser desorption ionization time-of-flight; Tricine, N-[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]glycine.2The abbreviations used are: Aβ, β-amyloid; AD, Alzheimer disease; APP, β-amyloid precursor protein; NA, normal aging (cognitively normal elderly subjects); AFM, atomic force microscopy; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; MALDI-TOF, matrix-assisted laser desorption ionization time-of-flight; Tricine, N-[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]glycine., a proteolytic product of transmembrane protein APP, is the primary pathogenic event of Alzheimer disease (AD) (1Selkoe D.J. J. Biol. Chem. 1996; 271: 18295-18298Abstract Full Text Full Text PDF PubMed Scopus (758) Google Scholar). Recent clues indicate that small, soluble Aβ aggregates produce more severe synaptic dysfunction and neuronal damage than do Aβ polymers (2Walsh D.M. Klyubin I. Fadeeva J.V. Cullen W.K. Anwyl R. Wolfe M.S. Rowan M.J. Selkoe D.J. Nature. 2002; 416: 535-539Crossref PubMed Scopus (3686) Google Scholar, 3Lue L.F. Kuo Y.M. Roher A.E. Brachova L. Shen Y. Sue L. Beach T. Kurth J.H. Rydel R.E. Rogers J. Am. J. Pathol. 1999; 155: 853-862Abstract Full Text Full Text PDF PubMed Scopus (1363) Google Scholar, 4Dahlgren K.N. Manelli A.M. Stine Jr., W.B. Baker L.K. Krafft G.A. LaDu M.J. J. Biol. Chem. 2002; 277: 32046-32053Abstract Full Text Full Text PDF PubMed Scopus (1235) Google Scholar, 5Lambert M.P. Barlow A.K. Chromy B.A. Edwards C. Freed R. Liosatos M. Morgan T.E. Rozovsky I. Trommer B. Viola K.L. Wals P. Zhang C. Finch C.E. Krafft G.A. Klein W.L. Proc. Natl. Acad. Sci. U. S. A. 1998; 95: 6448-6453Crossref PubMed Scopus (3113) Google Scholar). This behavior is common to all known pathogenic and nonpathogenic amyloidogenic peptides (6Kayed R. Head E. Thompson J.L. McIntire T.M. Milton S.C. Cotman C.W. Glabe C.G. Science. 2003; 300: 486-489Crossref PubMed Scopus (3437) Google Scholar, 7Bucciantini M. Giannoni E. Chiti F. Baroni F. Formigli L. Zurdo J. Taddei N. Ramponi G. Dobson C.M. Stefani M. Nature. 1996; 416: 507-511Crossref Scopus (2153) Google Scholar). Soluble Aβ is detectable early in the cerebral cortex of subjects at risk for AD pathology, several years before the formation and deposition of amyloid fibrils (8Teller J.K. Russo C. DeBusk L.M. Angelini G. Zaccheo D. Dagna-Bricarelli F. Scartezzini P. Bertolini S. Mann D.M. Tabaton M. Gambetti P. Nat. Med. 1996; 2: 93-95Crossref PubMed Scopus (321) Google Scholar). Hence, the analysis of soluble Aβ in brain tissue allows the characterization of the toxic form of the peptide. A strong argument against the amyloid hypothesis is the abundant and constant deposition of Aβ in the brains of elderly subjects, in the absence of signs of neuronal degeneration and dementia (9Armstrong R.A. Cairns N.J. Myers D. Smith C.U. Lantos P.L. Rossor M.N. Neurodegeneration. 1996; 5: 35-41Crossref PubMed Scopus (22) Google Scholar, 10Yamaguchi H. Sugihara S. Ogawa A. Saido T.C. Ihara Y. Acta Neuropathol. (Berl.). 1998; 95: 217-222Crossref PubMed Scopus (96) Google Scholar, 11Dickson D.W. Crystal H.A. Mattiace L.A. Masur D.M. Blau A.D. Davies P. Yen S.H. Aronson M.K. Neurobiol. Aging. 1992; 13: 179-189Crossref PubMed Scopus (533) Google Scholar). The reasons for the absence of pathogenic effect exerted by Aβ in normal aging are unknown. The issue has important therapeutic implications, because the major strategies to prevent and cure AD are focused on halting Aβ accumulation (12Hardy J. Selkoe D.J. Science. 2002; 297: 353Crossref PubMed Scopus (10962) Google Scholar). In brains from Alzheimer disease (AD) and Down syndrome patients, three major species of soluble Aβ have been identified by mass spectrometry: the full-length form, Aβ1-42, which has a relative molecular mass of 4.5 kDa, and two N-terminal peptides truncated at residue 3 (Aβ3-42) and residue 11 (Aβ11-42) with relative molecular masses of 4.2 and 3.5 kDa, respectively (13Russo C. Saido T.C. DeBusk L.M. Tabaton M. Gambetti P. Teller J.K. FEBS Lett. 1997; 409: 411-416Crossref PubMed Scopus (117) Google Scholar, 14Saido T.C. Yamao-Harigaya W. Iwatsubo T. Kawashima S. Neurosci. Lett. 1996; 215: 173-176Crossref PubMed Scopus (237) Google Scholar). The 4.2- and 3.5-kDa bands are more prominent in familial AD carrying presenilin 1 mutations than in sporadic AD, suggesting that the ratio of soluble Aβ species may dictate the toxicity of the aggregates (15Russo C. Schettini G. Saido T.C. Hulette C. Lippa C. Lannfelt L. Ghetti B. Gambetti P. Tabaton M. Teller J.K. Nature. 2000; 405: 531-532Crossref PubMed Scopus (133) Google Scholar). We predicted that the composition of soluble Aβ underlies the different effect exerted by the molecule in AD and in normal aging. To investigate this hypothesis, we studied the composition and properties of aggregation and toxicity as well as the damage produced on artificial membranes of soluble Aβ, comparing these areas in sporadic AD and cognitively normal elderly subjects with abundant amyloid plaques in cerebral cortex. Tissues—We used frozen blocks and formalin-fixed sections of frontal cortex from 14 cases with late onset sporadic AD (mean age at death 80 ± 8 years) (clinical history of disease; pathological diagnosis according to the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) criteria; post-mortem interval 8 h ± 3) provided by the brain bank of Case Western Reserve University, Cleveland, OH, and from 11 cognitively normally aging (NA) elderly subjects (mean age at death 83.3 ± 10 years; post-mortem interval 9.5 h ± 4). The latter subjects had be tested neuropsychologically annually and agreed to be autopsied for research purposes (provided by the Alzheimer's Disease Research Center, University of Kentucky). Their neuropsychological scores were within the range of normal. In cerebral cortex abundant Aβ plaques were present, with absent or scarce neurofibrillary pathology. The amount of Aβ plaques, as shown with monoclonal antibody 4G8, was semiquantitatively evaluated in three nonadjacent sections of frontal cortex and was comparable with that of AD cases. Immunoblot Analysis—Soluble Aβ was extracted from the water-soluble fraction of frontal cortex with a well established method described in detail previously (8Teller J.K. Russo C. DeBusk L.M. Angelini G. Zaccheo D. Dagna-Bricarelli F. Scartezzini P. Bertolini S. Mann D.M. Tabaton M. Gambetti P. Nat. Med. 1996; 2: 93-95Crossref PubMed Scopus (321) Google Scholar). Briefly, frozen tissues were homogenized in 4 volumes of saline buffer (50 mm Tris, pH 7.6, 5 mm EDTA, 150 mm NaCl) containing protease inhibitors and centrifuged at 100,000 × g for 1 h. Homogenization was also carried out with EDTA-free buffer. Soluble Aβ was immunoprecipitated from the supernatants (1 ml cor-responding to 250 mg of tissue) adjusted to 1× radioimmune precipitation assay buffer (150 mm NaCl, 1% Nonidet P-40, 0.5% cholic acid, 0.1% SDS, 50 mm Tris, pH 8, with protease inhibitors) with an antiserum raised against Aβ1-40 synthetic peptide (RGP9) that selectively recognizes Aβ region 1-3, as demonstrated with the selective reactivity with Aβ starting at position 1 only (Fig. 2A). Immunoprecipitation was carried out similarly with monoclonal antibody 4G8 (Signet Laboratories). To ascertain the state of aggregation of soluble Aβ, immunoprecipitation was also performed following filtration of supernatants using Amicon Ultra centrifugal filter unit devices with low-binding Ultracel membranes with a 10-kDa cut-off (Millipore). Immunoprecipitated proteins were separated on Tris-Tricine 10-18% gels and recognized by immunoblotting with monoclonal antibody 4G8, as well as with antibodies specific for N-terminal residues 1 (α-N1), 3 (α-py3), and 11 (α-py11) (the last two cyclized to pyroglutamate at their N termini) (14Saido T.C. Yamao-Harigaya W. Iwatsubo T. Kawashima S. Neurosci. Lett. 1996; 215: 173-176Crossref PubMed Scopus (237) Google Scholar). Antibodies specific for Aβ42 and Aβ40 were also used (IBL, Gunma, Japan). Brain-soluble fractions were also analyzed directly by immunoblotting following precipitation with methanol. Mixtures of synthetic peptides prepared as indicated below were immunoprecipitated with RGP9 anti-Aβ antiserum and analyzed by immunoblotting (Fig. 2B). MALDI-TOF Analysis—Immunoprecipitated synthetic peptides and tissue samples were all treated under the same conditions. Dried agarose beads were resuspended in 50 μl of 10% formic acid and agitated for 3 h at room temperature. 1 μl of the supernatant was loaded directly onto the MALDI target using the dried-droplet technique and α-cyano-4-hydroxycinnamic acid as matrix. Alternatively, 20 μl of the supernatant was subjected to a single desalting/concentration step before mass spectrometric analysis over a μZipTipC18 (Millipore Corp., Bedford, MA) and eluted in 1 μl of 50% CH3CN + 50% trifluoroacetic acid 0.2%. MALDI-TOF mass measurements were performed on a Voyager-DE STR (Applied Biosystems, Framingham, MA) operated in the reflectron mode. Spectra were calibrated externally using a standard peptide mixture. Immunocytochemistry—Immunocytochemisty was performed on formalin-fixed, paraffin-embedded sections of frontal cortex. Adjacent 6-μm-thick sections were processed according to the biotin-avidin method using antibodies specific for N-terminal residues 1 and 3 pyroglutamate (14Saido T.C. Yamao-Harigaya W. Iwatsubo T. Kawashima S. Neurosci. Lett. 1996; 215: 173-176Crossref PubMed Scopus (237) Google Scholar). Sections were pretreated with 98% formic acid for 10 min at room temperature. The reaction was developed with 3,3′-diaminobenzidine as co-substrate. The number of reactive Aβ plaques was determined in 12 fields of the cortex spanning the entire cortical thickness in three AD and three NA cases using an ocular grid of 0.135 mm2 at a final magnification of ×100. Preparation of Peptides—Synthetic peptides corresponding to the three major soluble Aβ species detected by immunoblotting (Aβ1-42, py3-42, and py11-42; Anaspec) were dissolved with 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP, Sigma) to produce a uniform, nonaggregated field of Aβ (12Hardy J. Selkoe D.J. Science. 2002; 297: 353Crossref PubMed Scopus (10962) Google Scholar). The studies on toxicity and aggregation are all based on different lots of peptides to avoid the possibility that results could depend on a variation in the synthetic peptide batches (Aβ1-42 lots 26048 and 31475, Aβpy3-42 lots 25479 and 28058, Aβpy11-42 lot 28001; Anaspec). The three synthetic Aβ peptides were suspended in phosphate-buffered saline at a ratio corresponding to the composition of soluble Aβ detected in AD (Aβ1-42, 36%; Aβpy3-42, 48%; Aβpy11-42, 16%) and NA (Aβ1-42, 50%; Aβpy3-42, 29%; Aβpy11-42, 21%) and kept for 24-48 h at room temperature at a final concentration of 10 μm, pH 7.6, for subsequent analyses. For experiments in immunoprecipitation and immunoblotting, peptides were kept at 37 °C for 24 h. was by of the Aβ corresponding to AD and NA at a concentration of 10 in at room temperature. For 20 of the were at various the aggregation on and under for were in using a with a were used and The were by the in and the corresponding in μl of AD and NA 10 μm, were to 1 in and was to the was using a with and at and with 5 and standard was in by Aβ peptides was evaluated by of the of as described previously A. S. R. A. C. C. M. G. M. Chiti F. Stefani M. J. Biol. PubMed Scopus Google Scholar). Aβ at different were at a final concentration of to a concentration To protein in the the was for The protein aggregation were the same as those used for The samples were at and was at using an with acid were at a concentration of 5 × in in μl of The and were at a concentration of 10 in phosphate-buffered saline at room temperature for 24 that the formation of aggregates Jr., W.B. K.N. Krafft G.A. LaDu M.J. J. Biol. Chem. 2003; Full Text Full Text PDF PubMed Scopus Google Scholar). were dissolved in at a concentration of 1 to the toxic effect K.N. Manelli A.M. Stine Jr., W.B. Baker L.K. Krafft G.A. LaDu M.J. J. Biol. Chem. 2002; 277: 32046-32053Abstract Full Text Full Text PDF PubMed Scopus (1235) Google and were to the for 24-48 h in conditions. was used as for was in phosphate-buffered saline to 5 as described by the The was 10% in 10 μl of was to well and for 3 h at μl of was to well and at 37 The of the samples was at an with was of Soluble Aβ Immunoblot by immunoblotting the soluble Aβ species in the cerebral cortex from subjects with sporadic AD and from cognitively with abundant amyloid plaques and scarce neurofibrillary (8Teller J.K. Russo C. DeBusk L.M. Angelini G. Zaccheo D. Dagna-Bricarelli F. Scartezzini P. Bertolini S. Mann D.M. Tabaton M. Gambetti P. Nat. Med. 1996; 2: 93-95Crossref PubMed Scopus (321) Google Scholar, C. Saido T.C. DeBusk L.M. Tabaton M. Gambetti P. Teller J.K. FEBS Lett. 1997; 409: 411-416Crossref PubMed Scopus (117) Google Scholar, M. R. M. L. Gambetti P. PubMed Scopus Google following immunoprecipitation with RGP9 antiserum and with monoclonal antibody 4G8, soluble Aβ three bands of 4.5 4.2 and 3.5 in all cases (Fig. was identified as the full-length Aβ using an antibody specific for Aβ starting at position The two bands with antibodies specific for Aβ at position 3 and Aβ at position 11 (Fig. that and are mostly mass of N-terminal truncated as previously (13Russo C. Saido T.C. DeBusk L.M. Tabaton M. Gambetti P. Teller J.K. FEBS Lett. 1997; 409: 411-416Crossref PubMed Scopus (117) Google Scholar, C. Schettini G. Saido T.C. Hulette C. Lippa C. Lannfelt L. Ghetti B. Gambetti P. Tabaton M. Teller J.K. Nature. 2000; 405: 531-532Crossref PubMed Scopus (133) Google Scholar). The antibody specific for Aβ42 recognized all three bands in NA and AD only was by the antibody specific for Aβ40 (Fig. The of Aβ40 reactivity was in NA and AD cases. This indicated that soluble Aβ to the Aβ42 form and that the Aβ40 species is only by the full-length peptide mass which from the amyloid J. Neuropathol. 1998; PubMed Scopus Google Scholar, H. H. N. H. T. T. P.L. 1997; PubMed Scopus Google in NA and AD cases. of Aβ species was in of fractions immunoprecipitated with monoclonal antibody 4G8 or analyzed directly following protein precipitation with (Fig. The results were by the or of in the buffer. In soluble Aβ was as aggregates of all Aβ which under of This was demonstrated by two the absence of Aβ in soluble fractions 10-kDa cut-off membranes (Fig. the of N-terminal truncated Aβ species with the full-length (Fig. immunoprecipitation with the antiserum which recognized only the three Aβ residues (Fig. 2A). The state of aggregation of soluble Aβ was by the of several oligomers from to (Fig. The reactivity of the Aβ oligomers with antibodies specific for different Aβ depends on of the of Aβ species within the of the described bands membranes were with the antibodies and A reactivity was 11 reactivity with the monoclonal antibody 4G8 was was more prominent for of soluble in AD than in NA brains in NA cases 50% of the (Fig. The of or of was in AD and NA ratio the three bands was following with the antibodies specific for N and that and to the three Aβ1-42, Aβpy3-42, and Aβpy11-42 synthetic peptides were in and analyzed by immunoblotting with monoclonal antibody 4G8, we a reactivity that to the relative of peptide (Fig. 2B). The ratio was also in the amyloid plaques in the frontal cortex of AD and NA In NA the antibody to recognized more Aβ plaques than the antibody to (mean number of Aβ plaques in 12 fields of the frontal cortex. ± ± (Fig. A and the ratio was in AD cases ± ± (Fig. and mass the of Aβ1-42, Aβpy3-42, and Aβpy11-42 as major as well as the of Aβ1-40 and N-terminal truncated peptides at residue (Fig. A and We that the latter truncated Aβ species with the we are to antibodies specific for the various N However, Aβ1-40 the N-terminal truncated species were detectable in all of the AD and NA cases (Fig. A and The ratio different Aβ species by Western was by MALDI-TOF the of Aβpy3-42 and Aβpy11-42 are than that This is to a specific of the from the Aβ as shown in and as demonstrated previously with peptides T. Y. P. D.J. Chem. PubMed Scopus Google Scholar). of Soluble the different of soluble Aβ species in different Aβ We the aggregation that the formation of Aβ oligomers with a concentration of Jr., W.B. K.N. Krafft G.A. LaDu M.J. J. Biol. Chem. 2003; Full Text Full Text PDF PubMed Scopus Google because is for Aβ (2Walsh D.M. Klyubin I. Fadeeva J.V. Cullen W.K. Anwyl R. Wolfe M.S. Rowan M.J. Selkoe D.J. Nature. 2002; 416: 535-539Crossref PubMed Scopus (3686) Google Scholar, 5Lambert M.P. Barlow A.K. Chromy B.A. Edwards C. Freed R. Liosatos M. Morgan T.E. Rozovsky I. Trommer B. Viola K.L. Wals P. Zhang C. Finch C.E. Krafft G.A. Klein W.L. Proc. Natl. Acad. Sci. U. S. A. 1998; 95: 6448-6453Crossref PubMed Scopus (3113) Google Scholar). A of the three synthetic Aβ peptides in the corresponding to those detected in NA and in AD were at room temperature for 24-48 h at a concentration of 10 μm, and the state of aggregation was by 24 Aβ peptides of ± in the detectable form of Aβ aggregation D.M. D.M. Y. Y. A. Selkoe D.J. J. Biol. Chem. 1999; Full Text Full Text PDF PubMed Scopus Google Scholar, C.M. Chem. Biol. 1997; Full Text PDF PubMed Scopus Google Scholar). these aggregates were in were more in the AD (Fig. h of the AD from the of which were absent in the NA (Fig. To the aggregation we analyzed the two of synthetic peptides using a The AD a of aggregation than the NA and the h (Fig. This was by assay of Soluble effect of soluble Aβ on was by with the two different of synthetic peptides at 1 in We used as the of the which has been shown to be a of toxicity D.M. D.M. Y. Y. A. Selkoe D.J. J. Biol. Chem. 1999; Full Text Full Text PDF PubMed Scopus Google Scholar). 24 h of the AD produced a of different from that of in with a by the NA (Fig. h of the AD and NA determined a 50 and of and the of the toxic effect of the two of Aβ aggregates was (Fig. The peptide used as a had effect on (Fig. of Aβ on of Aβ species has been to the of Aβ to H.A. D. T. Jr., Nature. 2002; PubMed Scopus Google we analyzed the of membranes by early aggregates of and Aβpy3-42, the peptides of soluble Aβ in NA and We from of and as an of as described previously A. S. R. A. C. C. M. G. M. Chiti F. Stefani M. J. Biol. PubMed Scopus Google Scholar). 12 h of Aβpy3-42 caused a of which was only by (Fig. The were with a of of the peptides (Fig. suggesting that Aβpy3-42 more the state of aggregation that the show that the soluble Aβ aggregates in AD and differ in composition from the aggregates with NA and a which be with the of the N-terminal truncated species over the full-length all N-terminal truncated Aβpy3-42 is the prominent form, as we by comparing the reactivity of specific antibody with that with the monoclonal antibody 4G8 that recognizes all Aβ species (Fig. The of Aβpy3-42 over the N-terminal truncated species that with the is by mass which only Aβpy3-42 in all cases The relative amount of Aβpy3-42 on the Aβ was previously by Y. Saido T.C. C.M. M. 2000; PubMed Scopus Google using a specific The pathogenic effect of Aβpy3-42 is by the that the Aβpy3-42 early aggregates the suggesting that form in the as has been for amyloidogenic peptides M. Dobson C.M. J. Med. 2003; PubMed Scopus Google Scholar). on the relative of N-terminal truncated Aβ aggregates may be with severe as in the of presenilin 1 (15Russo C. Schettini G. Saido T.C. Hulette C. Lippa C. Lannfelt L. Ghetti B. Gambetti P. Tabaton M. Teller J.K. Nature. 2000; 405: 531-532Crossref PubMed Scopus (133) Google or may a toxic as in The Aβpy3-42 species be from an or be produced from the full-length form by and by to pyroglutamate S. Saido T.C. Neurosci. Lett. 2002; PubMed Scopus Google Scholar). 1 is of at position 1 and 11 of Aβ 2002; PubMed Scopus Google and Aβ starting with residue 3 were analysis of was carried out in Neurobiol. 2003; PubMed Scopus Google Scholar). However, in a presenilin the Aβpy3-42 form was detected C. N. N. E. G. T. H. A. B. A. J. C. G. P. L. 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