Brain Research, 593 (1992) 299-303 © 1992 Elsevier Science Publishers B.V. All rights reserved 0006-8993/92/$05.00
299
BRES 25373
Senile plaques in cerebral amyloid angionathy show accumulation of amyloid precursor protein without cytoskeletal abnormalities M. T a b a t o n ~, S. C a m m a r a t a b T. M a n d y b u r ~, P. R i c h e y a, M. Kawai a, G. Perry a a n d P. G a m b e t t i a a Dicision of Neuropathology, Institute of PatholoD,, Case Western Reserce University, Cleveland, OH 44106, (USA) b h)stitute of Neurology, Unicersity of Genoa, Genoa (Italy) and e Division of Neuropathology, University of Cinc#mati, Cincinnati, OH (USA) (Accepted 30 June 1992)
Key words: Amyloid/3-protein; Alzheimer disease; Congophilic angiopathy; ¢; Senile plaque
The abnormal neurites that surround /3-amyloid in senile plaques (SP) in Alzheimer disease contain /~-amyloid precursor protein (/~APP) or abnormal filaments which react with antibodies to r. Occasionally,/3APP and abnormal filaments are present in the same neurite. Whether both types of abnormal neutites are reactive to the presence of//-amyloid or they are instead independent from each other is unknown. "re. begin to clarify this issue, we comparatively studied/3APP and r-epitopes in SP from cases of classical Alzheimer disease and cases of cerebral amyloid angiopathy, with SP but without neurofibrillary pathology. In subjects with cerebral amyloid angiopathy, about one-third of SP, the same percentage as in Alzheimer disease, were/3APP reactive in the absence of c-reactivity./3APP epitopes were ultrastructurally localized in dense bodies of probable lysosomal origin, adjacent to the core of SP. These resuhs demonstrate that /3APP and c-reactive c,~toskeletal alterations occur independently in the neurites of SP. The presence of/3APP in dystrophic neurites of SP and the localization of/~ APP in lysosomes suggest that//APP containing dystrophic neurites may play a role in the extracellular deposition of amyloid.
Abnormal neurites are a major histopathological feature of Alzheimer disease and correlate strongly with the cognitive impairment I. Two types of abnormal neurites are commonly described. Abnormal neurites associated with neuritic plaques and abnormal neurites with widespread distribution which are called neuropil threads z. According to immunocytochemical data, the former contain ubiquitin3, ¢4 and//-amyloid precursor protein (/3APP) s-9, while the latter only ¢ and ubiquitin t°. In a previous study, we have shown that neuropil threads are unrelated to the presence of amyloid 1°. However, the presence of ~--reactivity also in the plaque-associated neurites has raised the question of whether the reactivity to /3APP to as well as ¢ is secondary to the presence of amyloid deposits in the proximity of these neurites. To clarify this issue, we have examined the immunoreactivity of ¢ and //APP in brain of subjects with classical AD or with cerebral amyloid angiopathy (CAA). The brains from subjects with CAA contained
cortical SP but no ng,~rofibrillary tangles or neuropil threads ~1. Moreover;' the ultrastructural localization of flAPP plaque-associated ncuritcs from both groups was determJr,6d. Four AD cases, fulfilling the clinical and pathological criteria f,r AD ~z and three subjects with CAA previously de.,,:ribed II were examined. The CAA I ~tients had a clinical history of multiple lobar hemorrt "ges. Histologically, Congo red positive material was ,nfined to meningeal and neocortical arteries and c(~rticai grey matter. Silver staining did not reveal either n,:urofibrillary tangles or neuritic plaques. The post-mort,m interval ranged from 5 to 18 h in all seven cases. S~mples of cerebral cortex obtained a t autopsy were fixed in 10% buffered formalin or paraformaldehyde-lysine-periodic acid (PLP) for 24 h and paraffin embedded. The following antibodies were used: (1) rabbit antiserum to/]-amyloid (/3A) raised to a synthetic peptide homologous to //A 1-28 t3 (anti-flA); (2) rabbit anti-
Correspondence: M. Tabaton, Division of Neuropathology, Case Western Reserve University, 2~}85Adelbert Road, Cleveland, OH 44106, USA. Fax: (1) (216) 844-1810.
300 serum to the/]APP carboxyl terminus 675-6957 (anti/lAPP-C); (3) monoclonal antibody to/3APP mapping to an epitope located between amino acidic residues 70-100 of /~APP (Boehringer) t4 (anti-~APP-N); (4) affinits, purified rabbit antiserum to z L~. Six-tzm thick serial paraffin sections were processed according to the peroxidase-antiperoxidase protocol with anti-/3A, -r and with respectively, anti-/3APP-C or anti-~APP-N antibodies. All sections were counterstained with hemato~lin and eosin (H & E). The formalin fixed sections were pretreated with 80% formic acid for 10 min before immunostaining. The number of SP that reacted witl~--all the different antibodies used on PLP fixed sections without formic acid prctreatment was comparable with that obtained in formalin fixed, formic acid pretreated sections for two AD cases. The SP reactive with all the antibodies were counted in serial adjacent sections in three different microscopic fields of frontal cortex. The results were expressed as percentage of SP reactive with 13A antiserum.
k .
Fifty-/~m thick paraffin sections from PLP fixed blocks from two AD and two CAA cases were processed with anti-flAPP-C according to the preembedding colloidal gold method ~6. Portions of gold-labelled structures were trimmed, post-fixed in 2.5% glutaraldehyde and 2% OsO 4, dehydrated and flat embedded in Spurr's medium. Semi-thin sections were selected to ascertain the presence of gold labelle,~. SP. The adjacent ultrathin section was viewed with a Zeiss 101 electronmicroscope. In AD, anti-~A immunostained several amyloid deposits. Only circular deposits with a dense core were identified as SP and distinguished from diffuse amyloid deposits (Fig. 1A). Seventy'two percent of all SP contained z-immunoreaetive neurites (Table I). Anti-~APP antibodies immunostained globular profiles identifiable as neurites, which were topographically related to SP (Fig. 1B). The number of SP with /3APP reactive neurites was 29% for anti-/~APP-N and 32% for anti-/~APP-C (Table I). Almost all ~APP reactive SP were also z-reactive (Fig. 1C), although
0
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'k
i
i
L
.,~,.~,.
:~1~ . ,
•
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~ ,
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Fig. I. Serial scctk)ns of frontal cortex in Alzheimer disease. Several SP are recognized by/~-amyloid antiserum (A); most of them are also "r-immunoreactive (arrowheads) (C), while only two are immunostained with ami-~-APP-C (arrows) (B)•
301 TABLE I Quantitative epitopes analysis of SP b~ .4D and CA,4 cases Cases
Percentage of SP reactive with a gicen antibody
AD 1 AD 2 AD 3 AD 4 CAA 5 CAA 6 CAA 7
/JA 100 100 100 100 100 100 100
/3APP-C 35 31 32 29 39 ,16 43
/3APP-N 25 28 32 30 41 35 37
~" 80 68 71 68 0 0 0
within the SP the f l A P P and r-reactive neurites were not always the same. In the cases with CAA, anti-~A labelled SP as was the case for AD tissue (Fig. 2A). The density of SP was about one-third of that present in the A D cases. Diffuse amyloid deposits were rarely observed. As in A D cases, SP showed clusters of /3APP immunoreactive neurites (Fig. 2B). T h e percentage o f / 3 A P P reactive SP was slightly higher than in AD cases and varied from 38% (anti-APP-N) to 43% (anti-APP-C) (Table
I). In the adjacent sections, r-immunoreactivity was completely absent from SP neurites in CAA (Fig. 2C). Further, r-immunoreactivity was not observed in neuronal perikarya and neuropil threads, thus confirming the absence of abnormal cytoskeletal filaments in the cerebral cortex of CAA cases. In both AD or CAA tissues flAPP-C terminal epitopes were concentrated in dense bodies as well as in amorphous material adjacent to bundles of amyloid fibers forming the SP core (Fig. 3). The amyloid fibers, astroglial fibers and paired helical filaments (PHF) were not flAPP-C reactive. P H F were not observed in CAA cases. The present study indicates that abnormal neurites associated with SP contain/3APP in the absence of any z-reactive cytoskeletal alteration. This finding is in agreement with our previous data and those of others that T-reactive neurites are observed in SP only in the presence of NFT and that z-reactive neurites and N F T are an expression of the same cytoskeletal alteration t°'~7"ls. The finding that the abnormal neurites of SP are r-unreactive indicate that the r-reactivity in
i
Fig. 2. Serial sections of frontal cortex in cerebral amyloid angiopathy, fl-amyloidantibody (A) immunostains three SP, two of which (B) are al~o /3-amyloidprecursor protein (anti-flAPP-C)immunoreactive.The three SP are not immunostainedwith the ~--antibody(C) ( x 150).
302
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Fig. 3. Alzhcimcr's disease. Electron micrograph of ;i dystrophic neuritc in a SP immunostaineu with anti./3APP-C. Gold particles decorate dense bodies lind amorphous materi~d. Amyloid fibers (arrow) and paired helical filaments (arrowhead) are not labelled (bar = I/zm).
neurites is not secondary to the deposition of amyloid and we propose that the 1"-reactive ncurites in SP of AD are neuropil threads caught accidently in a site of amyloid deposition. We also show that ~APP epitopcs have a similar distribution in plaque associated neurites of classical AD and CAA, In both instances, they are located in amorphous material as well as in dense bodies, probably lysosomcs t'~ which are present in large numbers in the neurites that surround the amyloid core of SP ~~ in both conditions, The finding that the distribution o f / t A P P epitopes in plaque-associated ncurites is apparently unrelated to the presence of ~'-rcactivity is consistent with the hypothesis that the two events, i.e., v and/~APP rcactivitics, are not strictly related. Whether the /3APP present in dystrophic neurites surrounding SP plays a role in amyloid deposition remains to be established. The authors thank Drs. Bias Frangione and Dennis Selkoe h~r generously providing antisera to/~-amyloid and/3-amyloid precursor protein. Fhis work was supported by Grants NINCD$ N$ 14509-13, NIA ADRC AG,IIg(II2-[12,NIH NIA I R01 AGN$08155.I)2 and the Britton Fund and the CNR Center for Cerebral Neurophysiology, Genovi~, Italy.
I Arai, H,, Lee, M.-Y.V,, Otvos, L., Greenberg, B,D., Lowery, D.E,, Sharma, S.K., Schmidt, M,L. and Trojanowski, J.Q., Defiqcd neurofilamenl, T and #-amyloid precursor protein epitopcs
distinguish Alzheimer from non-Alzheimer senile plaques, Pro¢. Nail. Acad. $cL USA, 87 (1990) 2249-2253. 2 Barcikowska, M., Wisniewski, H.M,, Bancher, C. and GrundkeIqbal, !,, About Ihe presence of paired helical filaments in dystrophic neuritcs participating in the phtque formation, Acre Neurr~/~athoL, 78 (1989) 225~231. 3 Bra~k, H,, Braak, E., Grundke-lqbal, I, lind Iqbal, K,, Occur. rencc of ncurc';;;i ;~reads in the senile human heins in Alzheimer's disease: a (hi1,! Ioc.t;ons of paired helical filaments outside the Ileurofibrillaw tmlgles and senile plaques, Neuronal. Left., 65 (1986) 351-355, 4 Cras, P,, Kawai, M., Lowery, D,, Gonzalez-DeWhitt, P., Green. berg, B. and Perry, O,, Senile plaque neurites in AIzheimer disease accumulate amyloid precursor protein, Prec. Nail. Acrid. ScL USA, 88 (1991) 7552-7556. 5 Ghiso, ,1,, Tasliavini, F,, Timmers, W.F. and Frangion¢, B,, AIzheimer's disease amyloid precursor protein is present in senile plaques and cerebrospinal fluid: immunohistochemieal and biochemical characterization, Biochcm, Biophys, Res, Cmnmun., 163 ( 19891 43f1-437, 6 Joachim, C,, Garnes, D., Mt~,,is, J,. Ward, P., Frenkel, D, and Selkoe, D,J,, Antibodies to non-beta regions of the beta.amyloid precursor protein detect a subset of senile plaques, Am. J. Pathol., 138 (1991) 313-384, 7 Khaehaturian, Z,S,, Diagnosis of Alzheimer's disease, Arch. Neutel,, 42 (19851 1097-1105, 8 Mandybur, T,i,, The incidence of cerebral amyloid angiopathy in Alzheimer's disease, Neurology., 25 11975) 125-126, 9 McKee, A,C,, Kosik, K,S. and Kowall, N,W,, Neuritic pathology and dementia in AIzheimer's disease, Ann. Neurol,, 30 (1991) 156-165, 10 Nukim., N, and Ihara, Y, One of the antigenic determinants of paired helical filaments is related to tau protein, J. Biochem,, 89 119861 1541-154~. II Palmert, M.R., Podlisny, M,B. and Witkar, D.S., Antisera to an amino-terminal peptide detect the amyloid protein precurs,~r of AIzheimer's disease and recognize senile plaques, Biochem. Biophys, Res. Commmr,. 156 119881 432-437.
303 12 Perry, G., Friedman, R., Shaw, G. and Chau, V., Ubiquitin is detected in neurofibrillary tangles and senile plaque neurites of AIzheimer disease brains, Proc. Natl. Acad. Sci. USA, 84 (1987) 3033-3036. 13 Perry, G., Kawai, M., Tabaton, M., Onorato, M., Mulvihill, S., Richey, P., Morandi, A., Connolly, J.A. and Gambetti, P., Neuropil threads of AIzheimer's disease show a marked alteration of the normal cytoskeleton, J. Neurosci., I 1 (1991) 1748-1755. 14 Perry, G., Lipphardt, S, Kancherla, M., Gambetti, P., Maggiora, L., Lobl, T., Mulvihill, P., Mijares, M., Sharma, S., Cornette, J. and Greenberg, B., Amyloid precursor proteins in senile plaques of Alzheimer's disease, Lancet, ii (1988) 746. 15 Tabaton, M., Mandybur, T.I., Perry, G., Onorato, M., AutilioGambetti, L, and Gambetti, P., The widespread ~dteration of neurites in Alzheimer's disease may be unrelated to amyloid deposition, Ann. Neurol., 26 (1989) 771-778. 16 Tabaton, M., Whitehouse, P.J., Perry, G., Autilio-Gambetti, L. and Gambetti, P., AIz-50 recognizes abnormal filaments in
Alzheimer's discas¢ and progressive supranuclear palsy, Amz. Neurol., 24 (19881 407-413. 17 Weidemann~ A "'~,'i7 ~ D,,~I.~ r ~ t:;,..:.ber,p.. Sa!baum JM. and Beyreuth~r, K., Identification, biogenesis and localization of precursor of A!zheimer's disease A4 amyloid protein, Cell, 57 (1989) 113-126. 18 Probst, A., Anderton, B.A., Brion, S.P. and Ulrich, J., Senile plaque neurites fail to demonstrate anti-paired helical and antimicrotubule associated protein tau immunoreactive proteins in the absence of neurofibrillary tangles in the neocortex, Acta Neuropathol., 77 (1989) 430-436. 19 Suzuki, K. and Terry, R., Fine structural localization of acid phosphatase in senile plaques in AIzheimer's presenile dementia, Acta New.'opathoL, 8 (1967) 276-287. 20 Terry, R.D., Gonatas, N.K. and Weiss, M., Ultrastructural studies in Alzheimer's presenile dementia, Am. J. Pathol., 44 (1964) 269-297.
299
BRES 25373
Senile plaques in cerebral amyloid angionathy show accumulation of amyloid precursor protein without cytoskeletal abnormalities M. T a b a t o n ~, S. C a m m a r a t a b T. M a n d y b u r ~, P. R i c h e y a, M. Kawai a, G. Perry a a n d P. G a m b e t t i a a Dicision of Neuropathology, Institute of PatholoD,, Case Western Reserce University, Cleveland, OH 44106, (USA) b h)stitute of Neurology, Unicersity of Genoa, Genoa (Italy) and e Division of Neuropathology, University of Cinc#mati, Cincinnati, OH (USA) (Accepted 30 June 1992)
Key words: Amyloid/3-protein; Alzheimer disease; Congophilic angiopathy; ¢; Senile plaque
The abnormal neurites that surround /3-amyloid in senile plaques (SP) in Alzheimer disease contain /~-amyloid precursor protein (/~APP) or abnormal filaments which react with antibodies to r. Occasionally,/3APP and abnormal filaments are present in the same neurite. Whether both types of abnormal neutites are reactive to the presence of//-amyloid or they are instead independent from each other is unknown. "re. begin to clarify this issue, we comparatively studied/3APP and r-epitopes in SP from cases of classical Alzheimer disease and cases of cerebral amyloid angiopathy, with SP but without neurofibrillary pathology. In subjects with cerebral amyloid angiopathy, about one-third of SP, the same percentage as in Alzheimer disease, were/3APP reactive in the absence of c-reactivity./3APP epitopes were ultrastructurally localized in dense bodies of probable lysosomal origin, adjacent to the core of SP. These resuhs demonstrate that /3APP and c-reactive c,~toskeletal alterations occur independently in the neurites of SP. The presence of/3APP in dystrophic neurites of SP and the localization of/~ APP in lysosomes suggest that//APP containing dystrophic neurites may play a role in the extracellular deposition of amyloid.
Abnormal neurites are a major histopathological feature of Alzheimer disease and correlate strongly with the cognitive impairment I. Two types of abnormal neurites are commonly described. Abnormal neurites associated with neuritic plaques and abnormal neurites with widespread distribution which are called neuropil threads z. According to immunocytochemical data, the former contain ubiquitin3, ¢4 and//-amyloid precursor protein (/3APP) s-9, while the latter only ¢ and ubiquitin t°. In a previous study, we have shown that neuropil threads are unrelated to the presence of amyloid 1°. However, the presence of ~--reactivity also in the plaque-associated neurites has raised the question of whether the reactivity to /3APP to as well as ¢ is secondary to the presence of amyloid deposits in the proximity of these neurites. To clarify this issue, we have examined the immunoreactivity of ¢ and //APP in brain of subjects with classical AD or with cerebral amyloid angiopathy (CAA). The brains from subjects with CAA contained
cortical SP but no ng,~rofibrillary tangles or neuropil threads ~1. Moreover;' the ultrastructural localization of flAPP plaque-associated ncuritcs from both groups was determJr,6d. Four AD cases, fulfilling the clinical and pathological criteria f,r AD ~z and three subjects with CAA previously de.,,:ribed II were examined. The CAA I ~tients had a clinical history of multiple lobar hemorrt "ges. Histologically, Congo red positive material was ,nfined to meningeal and neocortical arteries and c(~rticai grey matter. Silver staining did not reveal either n,:urofibrillary tangles or neuritic plaques. The post-mort,m interval ranged from 5 to 18 h in all seven cases. S~mples of cerebral cortex obtained a t autopsy were fixed in 10% buffered formalin or paraformaldehyde-lysine-periodic acid (PLP) for 24 h and paraffin embedded. The following antibodies were used: (1) rabbit antiserum to/]-amyloid (/3A) raised to a synthetic peptide homologous to //A 1-28 t3 (anti-flA); (2) rabbit anti-
Correspondence: M. Tabaton, Division of Neuropathology, Case Western Reserve University, 2~}85Adelbert Road, Cleveland, OH 44106, USA. Fax: (1) (216) 844-1810.
300 serum to the/]APP carboxyl terminus 675-6957 (anti/lAPP-C); (3) monoclonal antibody to/3APP mapping to an epitope located between amino acidic residues 70-100 of /~APP (Boehringer) t4 (anti-~APP-N); (4) affinits, purified rabbit antiserum to z L~. Six-tzm thick serial paraffin sections were processed according to the peroxidase-antiperoxidase protocol with anti-/3A, -r and with respectively, anti-/3APP-C or anti-~APP-N antibodies. All sections were counterstained with hemato~lin and eosin (H & E). The formalin fixed sections were pretreated with 80% formic acid for 10 min before immunostaining. The number of SP that reacted witl~--all the different antibodies used on PLP fixed sections without formic acid prctreatment was comparable with that obtained in formalin fixed, formic acid pretreated sections for two AD cases. The SP reactive with all the antibodies were counted in serial adjacent sections in three different microscopic fields of frontal cortex. The results were expressed as percentage of SP reactive with 13A antiserum.
k .
Fifty-/~m thick paraffin sections from PLP fixed blocks from two AD and two CAA cases were processed with anti-flAPP-C according to the preembedding colloidal gold method ~6. Portions of gold-labelled structures were trimmed, post-fixed in 2.5% glutaraldehyde and 2% OsO 4, dehydrated and flat embedded in Spurr's medium. Semi-thin sections were selected to ascertain the presence of gold labelle,~. SP. The adjacent ultrathin section was viewed with a Zeiss 101 electronmicroscope. In AD, anti-~A immunostained several amyloid deposits. Only circular deposits with a dense core were identified as SP and distinguished from diffuse amyloid deposits (Fig. 1A). Seventy'two percent of all SP contained z-immunoreaetive neurites (Table I). Anti-~APP antibodies immunostained globular profiles identifiable as neurites, which were topographically related to SP (Fig. 1B). The number of SP with /3APP reactive neurites was 29% for anti-/~APP-N and 32% for anti-/~APP-C (Table I). Almost all ~APP reactive SP were also z-reactive (Fig. 1C), although
0
I
'k
i
i
L
.,~,.~,.
:~1~ . ,
•
•
~ ,
-,~
~, .
~ ,
%.
~L
•
!
Fig. I. Serial scctk)ns of frontal cortex in Alzheimer disease. Several SP are recognized by/~-amyloid antiserum (A); most of them are also "r-immunoreactive (arrowheads) (C), while only two are immunostained with ami-~-APP-C (arrows) (B)•
301 TABLE I Quantitative epitopes analysis of SP b~ .4D and CA,4 cases Cases
Percentage of SP reactive with a gicen antibody
AD 1 AD 2 AD 3 AD 4 CAA 5 CAA 6 CAA 7
/JA 100 100 100 100 100 100 100
/3APP-C 35 31 32 29 39 ,16 43
/3APP-N 25 28 32 30 41 35 37
~" 80 68 71 68 0 0 0
within the SP the f l A P P and r-reactive neurites were not always the same. In the cases with CAA, anti-~A labelled SP as was the case for AD tissue (Fig. 2A). The density of SP was about one-third of that present in the A D cases. Diffuse amyloid deposits were rarely observed. As in A D cases, SP showed clusters of /3APP immunoreactive neurites (Fig. 2B). T h e percentage o f / 3 A P P reactive SP was slightly higher than in AD cases and varied from 38% (anti-APP-N) to 43% (anti-APP-C) (Table
I). In the adjacent sections, r-immunoreactivity was completely absent from SP neurites in CAA (Fig. 2C). Further, r-immunoreactivity was not observed in neuronal perikarya and neuropil threads, thus confirming the absence of abnormal cytoskeletal filaments in the cerebral cortex of CAA cases. In both AD or CAA tissues flAPP-C terminal epitopes were concentrated in dense bodies as well as in amorphous material adjacent to bundles of amyloid fibers forming the SP core (Fig. 3). The amyloid fibers, astroglial fibers and paired helical filaments (PHF) were not flAPP-C reactive. P H F were not observed in CAA cases. The present study indicates that abnormal neurites associated with SP contain/3APP in the absence of any z-reactive cytoskeletal alteration. This finding is in agreement with our previous data and those of others that T-reactive neurites are observed in SP only in the presence of NFT and that z-reactive neurites and N F T are an expression of the same cytoskeletal alteration t°'~7"ls. The finding that the abnormal neurites of SP are r-unreactive indicate that the r-reactivity in
i
Fig. 2. Serial sections of frontal cortex in cerebral amyloid angiopathy, fl-amyloidantibody (A) immunostains three SP, two of which (B) are al~o /3-amyloidprecursor protein (anti-flAPP-C)immunoreactive.The three SP are not immunostainedwith the ~--antibody(C) ( x 150).
302
•
,
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.+~"+" . " - "
~
:~'~
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~'
~
~ " " ~
~
++¢"A"7l~
"
=4~ ,'~'
~
~
, '
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+
Fig. 3. Alzhcimcr's disease. Electron micrograph of ;i dystrophic neuritc in a SP immunostaineu with anti./3APP-C. Gold particles decorate dense bodies lind amorphous materi~d. Amyloid fibers (arrow) and paired helical filaments (arrowhead) are not labelled (bar = I/zm).
neurites is not secondary to the deposition of amyloid and we propose that the 1"-reactive ncurites in SP of AD are neuropil threads caught accidently in a site of amyloid deposition. We also show that ~APP epitopcs have a similar distribution in plaque associated neurites of classical AD and CAA, In both instances, they are located in amorphous material as well as in dense bodies, probably lysosomcs t'~ which are present in large numbers in the neurites that surround the amyloid core of SP ~~ in both conditions, The finding that the distribution o f / t A P P epitopes in plaque-associated ncurites is apparently unrelated to the presence of ~'-rcactivity is consistent with the hypothesis that the two events, i.e., v and/~APP rcactivitics, are not strictly related. Whether the /3APP present in dystrophic neurites surrounding SP plays a role in amyloid deposition remains to be established. The authors thank Drs. Bias Frangione and Dennis Selkoe h~r generously providing antisera to/~-amyloid and/3-amyloid precursor protein. Fhis work was supported by Grants NINCD$ N$ 14509-13, NIA ADRC AG,IIg(II2-[12,NIH NIA I R01 AGN$08155.I)2 and the Britton Fund and the CNR Center for Cerebral Neurophysiology, Genovi~, Italy.
I Arai, H,, Lee, M.-Y.V,, Otvos, L., Greenberg, B,D., Lowery, D.E,, Sharma, S.K., Schmidt, M,L. and Trojanowski, J.Q., Defiqcd neurofilamenl, T and #-amyloid precursor protein epitopcs
distinguish Alzheimer from non-Alzheimer senile plaques, Pro¢. Nail. Acad. $cL USA, 87 (1990) 2249-2253. 2 Barcikowska, M., Wisniewski, H.M,, Bancher, C. and GrundkeIqbal, !,, About Ihe presence of paired helical filaments in dystrophic neuritcs participating in the phtque formation, Acre Neurr~/~athoL, 78 (1989) 225~231. 3 Bra~k, H,, Braak, E., Grundke-lqbal, I, lind Iqbal, K,, Occur. rencc of ncurc';;;i ;~reads in the senile human heins in Alzheimer's disease: a (hi1,! Ioc.t;ons of paired helical filaments outside the Ileurofibrillaw tmlgles and senile plaques, Neuronal. Left., 65 (1986) 351-355, 4 Cras, P,, Kawai, M., Lowery, D,, Gonzalez-DeWhitt, P., Green. berg, B. and Perry, O,, Senile plaque neurites in AIzheimer disease accumulate amyloid precursor protein, Prec. Nail. Acrid. ScL USA, 88 (1991) 7552-7556. 5 Ghiso, ,1,, Tasliavini, F,, Timmers, W.F. and Frangion¢, B,, AIzheimer's disease amyloid precursor protein is present in senile plaques and cerebrospinal fluid: immunohistochemieal and biochemical characterization, Biochcm, Biophys, Res, Cmnmun., 163 ( 19891 43f1-437, 6 Joachim, C,, Garnes, D., Mt~,,is, J,. Ward, P., Frenkel, D, and Selkoe, D,J,, Antibodies to non-beta regions of the beta.amyloid precursor protein detect a subset of senile plaques, Am. J. Pathol., 138 (1991) 313-384, 7 Khaehaturian, Z,S,, Diagnosis of Alzheimer's disease, Arch. Neutel,, 42 (19851 1097-1105, 8 Mandybur, T,i,, The incidence of cerebral amyloid angiopathy in Alzheimer's disease, Neurology., 25 11975) 125-126, 9 McKee, A,C,, Kosik, K,S. and Kowall, N,W,, Neuritic pathology and dementia in AIzheimer's disease, Ann. Neurol,, 30 (1991) 156-165, 10 Nukim., N, and Ihara, Y, One of the antigenic determinants of paired helical filaments is related to tau protein, J. Biochem,, 89 119861 1541-154~. II Palmert, M.R., Podlisny, M,B. and Witkar, D.S., Antisera to an amino-terminal peptide detect the amyloid protein precurs,~r of AIzheimer's disease and recognize senile plaques, Biochem. Biophys, Res. Commmr,. 156 119881 432-437.
303 12 Perry, G., Friedman, R., Shaw, G. and Chau, V., Ubiquitin is detected in neurofibrillary tangles and senile plaque neurites of AIzheimer disease brains, Proc. Natl. Acad. Sci. USA, 84 (1987) 3033-3036. 13 Perry, G., Kawai, M., Tabaton, M., Onorato, M., Mulvihill, S., Richey, P., Morandi, A., Connolly, J.A. and Gambetti, P., Neuropil threads of AIzheimer's disease show a marked alteration of the normal cytoskeleton, J. Neurosci., I 1 (1991) 1748-1755. 14 Perry, G., Lipphardt, S, Kancherla, M., Gambetti, P., Maggiora, L., Lobl, T., Mulvihill, P., Mijares, M., Sharma, S., Cornette, J. and Greenberg, B., Amyloid precursor proteins in senile plaques of Alzheimer's disease, Lancet, ii (1988) 746. 15 Tabaton, M., Mandybur, T.I., Perry, G., Onorato, M., AutilioGambetti, L, and Gambetti, P., The widespread ~dteration of neurites in Alzheimer's disease may be unrelated to amyloid deposition, Ann. Neurol., 26 (1989) 771-778. 16 Tabaton, M., Whitehouse, P.J., Perry, G., Autilio-Gambetti, L. and Gambetti, P., AIz-50 recognizes abnormal filaments in
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