- Email: [email protected]
Amyloid P component in neurofibrillary tangles, cortical plaques and cerebrospinal fluid in Alzheimer's disease and related disorders
270
NEUROBIOLOGY OF' AGING, VOLUME ii, 199() ABSI'RACTS Of~ SECOND INTERNATIONAL CONFERENCE ON ALZHEIMER'S DISEASE NEUROPATHOLOGY/ALZHEIMER'S DISEASE IN DEVELOPMENTAL DISABI[.ITIES
adjacent entorhinal cortex and neocortex and from the neostriatum were stained for acetylcholinesterase (ACHE). Adjacent hippocampal tissues from the five brains with the most numerous senile plaques as shown in AChE-tissue blocks were embedded in paraffin and sections were stained with a polyclonal antibody against synthetic beta-protein 1-42 (Masters et al.,) after treatment with 90% formic acid. The morphological aspects of plaques as stained for beta-protein and AChE were compared. In further selected cases with many plaques adjacent cryostat sections were stained for beta-protein and AChE respectively. The same plaques and plaque-like structures including the amorphous, diffuse and subpial beta-protein deposits not demonstrable with conventional histological techniques were observed. These findings suggest, that high AChE activity is intimately associated with the process of beta-protein formation and accumulation in plaques and that this association already occurs in a very early stage of plaque formation. Plaque-bound AChE activity could possibly not be observed in the beta-protein deposits of the striatum, possibly because the reaction was masked by high background AChE activity of the striatum. 71 NORMAL CONSTITUTIVE PROCESSING OF THE ALZHEIMER AMYLOID PRECURSOR PROTEIN PROTEOLYZES THE BETA AMYLOID PEPTIDE *F.S. Esch, P.S. Keim, E.C. Beattie, R.W. Blacher, A.R. Culweli, T. Oltersdorf, D. McClure ¶ and P.J. Ward. Athena Neurosciences Inc., 800F Gateway Blvd. South San Francisco, CA 94080 and Lilly Research Labs ¶ , Indianapolis, Indiana 46285. The beta-amyloid peptide [13-AP] is a small fragment of the much larger and broadly distributed amyloid precursor protein [APP]; the relative absence of 13-AP deposition in normal brain suggests that altered processing of APP occurs in AD and may represent a key pathogenic event in the disease. Constitutive processing of the APP results in the secretion of a large, soluble, N-terminal APP fragment and the generation of a membrane-bound 9 kD C-terminal APP fragment. We have purified both APP fragments from human embryonic kidney 293 cells transfected with cDNAs encoding the 695 and 751 amino acid forms of the APP; direct protein microsequencing, mass spectrometry and amino acid analyses of these N- and C-terminal APP fragments have shown that both APP695 and APP751 are p r o t e o l y t i c a l l y ~:l~vg~ within the g-AP s e o u e n ~ to generate these fragments. Thus, the formation an~l ~12O~iti0i3 of the B-AP is erecluded bv normal constitutivQ orocessino in 293 cells. These observations suggest the p o s s i b i l i t y that ~-AP deposition and the pathological formation of amyloid-bearing senile plaques in Alzheimer's disease may result from a deficit in this processing event. 72 AMYLOID P COMPONINT I N NllUitOirZillP.XLL~¥ TANGLES,
CORTICflkL PLI&QUIB ~HD CBRIBROSPIHI&L FLUID IN ~L~I~XMER'8 DISRKSB AND RBLKTBD D/BORDERS. *R. N. Kalaria. Departments of Neurology and Neuroscience, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, U S A Serum amyloid P identical to amyloid P component, (AP) is an ul-glycoprotein shown to be consistently present in all types of amyloid deposits except cerebral lesions of neurofibrillary tangles and
senile plaques. We used immunohistochemical methods to demonstrate AP immunoreactivity in both tangles and plaques, as well as vessels, in lightly fixed cryostat tissue sections of neocortex and hippocampus from subjects with Alzheimer's disease (AD) and other related neurodegenerative diseases. Heavy deposition of immunoperoxidase reaction product was evident in all the classical amyloidotic lesions of all cortical areas of AD cases examined. Senile plaques of Cruetzfeld-Jakob disease and Down's syndrome, Pick bodies of a Pick's case and tangles and vessels in Parkinson's disease were also stained. The distribution and intensity of immunostaining were similar to that of thioflavin S staining in serial sections. However, in some AD cases plaques were stained by AP that were not apparent by thioflavin S. Serial sections stained with antiserum to amyloid A or albumin, preimmune rabbit serum or preabsorbed AP serum showed no evidence for reactivity. AP immunoreactivity is also localised in amyloid deposits containing heparan sulphate proteoglycans and calcium. Intense AP reactivity in the 26K dalton band was also evident in immunoblots of cerebrospinal fluid from AD subjects. These observations provide evidence for extravasation of the protein across the bloodbrain barrier (BBB) in disease and may suggest impairment of the BBB. However, expression of AP by reactive cells within or those infiltrating into brain through the BBB cannot be ruled out. Supported by an ADRDA investigator-initiated award.
73 M O R P H O L O G I C A L / N E U R O C H E M I C A L C O R R E L A T E S OF DEPRESSION AND PSYCHOSIS IN PRIMARY DEMENTIA. G.S. Zubenko, J. Moossy, *J. Rosen, A.J. Martinez, G.R. Rag, D. Claassen, U. Kopp. University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213 USA Major depression and psychosis are important sources of comorbidity in patients with Alzbeimer's disease. Clinically-significant major depression emerged in 14 of 37 patients with primary dementia. Major depression in this context was associated with increased degeneration in the locus ceruleus (LC) and the substantia nigra (SN). Indices of neurodegeneration included neuronal loss, extraneuronal pigment, astrocytosis, and cells containing neurofibrillary tangles (NFT) or Lewy bodies (LB). Models that incorporated data from both of these nuclei more accurately predicted the emergence of major depression than those that included data from either nucleus alone, suggesting an interactive role of these aminergic systems in the pathogenesis of depression. As expected from the morphological studies, major depression was associated with significant reductions in the levels of norepinephrine (NE), particularly in neocortex. Dopamine (DA) levels were not decreased in seven cortical and subccrtical areas, even though the degrees of neurodegeneration in the LC and SN associated with depression were similar. The source of the apparent differential sensitivity of LC neurons to degenerative changes is uncertain. Major depression was associated with a consistent reduct.ion in serotonin (5HT) levels in all regions examined, although the reduction did not reach statistical significance in any single region. Choline acetyltransferase (CHAT), while reduced compared to control levels, was relatively preserved in subcortical regions of patients with major depression and suggests that a minimum threshold of cholinergic function may be required for the expression of major depression. Psychosis, defmed as the presence of delusions or hallucinations, emerged in 13 of 27 patients with histologically-confirmed Alzheimer's disease prior to death. In contrast to major depression, psychosis was associated with an increased density of senile plaques and neurofibrillary tangles in the prosubiculum and frontal cortex, respectively. Moreover, psychosis was not associated with consistent changes in the levels of arcane neurotransmitters or ChAT activity in the cortical and subcortical regions examined. In summary, major depression and psychosis are debilitating behavioral syndromes that commonly occur in patients with primary dementia. However, they appear to emerge independently and to have different anatomical, morphological, and neurochemical substrates. 74
DEGENERATION OF CORTICOCORTICAL GLUTAMATERGIC PATHWAYS AND ITS TREATMENT D.M. Bowen, Department of Neurochemistry, Institute for Neurology, London, U.K.
NEUROBIOLOGY OF' AGING, VOLUME ii, 199() ABSI'RACTS Of~ SECOND INTERNATIONAL CONFERENCE ON ALZHEIMER'S DISEASE NEUROPATHOLOGY/ALZHEIMER'S DISEASE IN DEVELOPMENTAL DISABI[.ITIES
adjacent entorhinal cortex and neocortex and from the neostriatum were stained for acetylcholinesterase (ACHE). Adjacent hippocampal tissues from the five brains with the most numerous senile plaques as shown in AChE-tissue blocks were embedded in paraffin and sections were stained with a polyclonal antibody against synthetic beta-protein 1-42 (Masters et al.,) after treatment with 90% formic acid. The morphological aspects of plaques as stained for beta-protein and AChE were compared. In further selected cases with many plaques adjacent cryostat sections were stained for beta-protein and AChE respectively. The same plaques and plaque-like structures including the amorphous, diffuse and subpial beta-protein deposits not demonstrable with conventional histological techniques were observed. These findings suggest, that high AChE activity is intimately associated with the process of beta-protein formation and accumulation in plaques and that this association already occurs in a very early stage of plaque formation. Plaque-bound AChE activity could possibly not be observed in the beta-protein deposits of the striatum, possibly because the reaction was masked by high background AChE activity of the striatum. 71 NORMAL CONSTITUTIVE PROCESSING OF THE ALZHEIMER AMYLOID PRECURSOR PROTEIN PROTEOLYZES THE BETA AMYLOID PEPTIDE *F.S. Esch, P.S. Keim, E.C. Beattie, R.W. Blacher, A.R. Culweli, T. Oltersdorf, D. McClure ¶ and P.J. Ward. Athena Neurosciences Inc., 800F Gateway Blvd. South San Francisco, CA 94080 and Lilly Research Labs ¶ , Indianapolis, Indiana 46285. The beta-amyloid peptide [13-AP] is a small fragment of the much larger and broadly distributed amyloid precursor protein [APP]; the relative absence of 13-AP deposition in normal brain suggests that altered processing of APP occurs in AD and may represent a key pathogenic event in the disease. Constitutive processing of the APP results in the secretion of a large, soluble, N-terminal APP fragment and the generation of a membrane-bound 9 kD C-terminal APP fragment. We have purified both APP fragments from human embryonic kidney 293 cells transfected with cDNAs encoding the 695 and 751 amino acid forms of the APP; direct protein microsequencing, mass spectrometry and amino acid analyses of these N- and C-terminal APP fragments have shown that both APP695 and APP751 are p r o t e o l y t i c a l l y ~:l~vg~ within the g-AP s e o u e n ~ to generate these fragments. Thus, the formation an~l ~12O~iti0i3 of the B-AP is erecluded bv normal constitutivQ orocessino in 293 cells. These observations suggest the p o s s i b i l i t y that ~-AP deposition and the pathological formation of amyloid-bearing senile plaques in Alzheimer's disease may result from a deficit in this processing event. 72 AMYLOID P COMPONINT I N NllUitOirZillP.XLL~¥ TANGLES,
CORTICflkL PLI&QUIB ~HD CBRIBROSPIHI&L FLUID IN ~L~I~XMER'8 DISRKSB AND RBLKTBD D/BORDERS. *R. N. Kalaria. Departments of Neurology and Neuroscience, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, U S A Serum amyloid P identical to amyloid P component, (AP) is an ul-glycoprotein shown to be consistently present in all types of amyloid deposits except cerebral lesions of neurofibrillary tangles and
senile plaques. We used immunohistochemical methods to demonstrate AP immunoreactivity in both tangles and plaques, as well as vessels, in lightly fixed cryostat tissue sections of neocortex and hippocampus from subjects with Alzheimer's disease (AD) and other related neurodegenerative diseases. Heavy deposition of immunoperoxidase reaction product was evident in all the classical amyloidotic lesions of all cortical areas of AD cases examined. Senile plaques of Cruetzfeld-Jakob disease and Down's syndrome, Pick bodies of a Pick's case and tangles and vessels in Parkinson's disease were also stained. The distribution and intensity of immunostaining were similar to that of thioflavin S staining in serial sections. However, in some AD cases plaques were stained by AP that were not apparent by thioflavin S. Serial sections stained with antiserum to amyloid A or albumin, preimmune rabbit serum or preabsorbed AP serum showed no evidence for reactivity. AP immunoreactivity is also localised in amyloid deposits containing heparan sulphate proteoglycans and calcium. Intense AP reactivity in the 26K dalton band was also evident in immunoblots of cerebrospinal fluid from AD subjects. These observations provide evidence for extravasation of the protein across the bloodbrain barrier (BBB) in disease and may suggest impairment of the BBB. However, expression of AP by reactive cells within or those infiltrating into brain through the BBB cannot be ruled out. Supported by an ADRDA investigator-initiated award.
73 M O R P H O L O G I C A L / N E U R O C H E M I C A L C O R R E L A T E S OF DEPRESSION AND PSYCHOSIS IN PRIMARY DEMENTIA. G.S. Zubenko, J. Moossy, *J. Rosen, A.J. Martinez, G.R. Rag, D. Claassen, U. Kopp. University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213 USA Major depression and psychosis are important sources of comorbidity in patients with Alzbeimer's disease. Clinically-significant major depression emerged in 14 of 37 patients with primary dementia. Major depression in this context was associated with increased degeneration in the locus ceruleus (LC) and the substantia nigra (SN). Indices of neurodegeneration included neuronal loss, extraneuronal pigment, astrocytosis, and cells containing neurofibrillary tangles (NFT) or Lewy bodies (LB). Models that incorporated data from both of these nuclei more accurately predicted the emergence of major depression than those that included data from either nucleus alone, suggesting an interactive role of these aminergic systems in the pathogenesis of depression. As expected from the morphological studies, major depression was associated with significant reductions in the levels of norepinephrine (NE), particularly in neocortex. Dopamine (DA) levels were not decreased in seven cortical and subccrtical areas, even though the degrees of neurodegeneration in the LC and SN associated with depression were similar. The source of the apparent differential sensitivity of LC neurons to degenerative changes is uncertain. Major depression was associated with a consistent reduct.ion in serotonin (5HT) levels in all regions examined, although the reduction did not reach statistical significance in any single region. Choline acetyltransferase (CHAT), while reduced compared to control levels, was relatively preserved in subcortical regions of patients with major depression and suggests that a minimum threshold of cholinergic function may be required for the expression of major depression. Psychosis, defmed as the presence of delusions or hallucinations, emerged in 13 of 27 patients with histologically-confirmed Alzheimer's disease prior to death. In contrast to major depression, psychosis was associated with an increased density of senile plaques and neurofibrillary tangles in the prosubiculum and frontal cortex, respectively. Moreover, psychosis was not associated with consistent changes in the levels of arcane neurotransmitters or ChAT activity in the cortical and subcortical regions examined. In summary, major depression and psychosis are debilitating behavioral syndromes that commonly occur in patients with primary dementia. However, they appear to emerge independently and to have different anatomical, morphological, and neurochemical substrates. 74
DEGENERATION OF CORTICOCORTICAL GLUTAMATERGIC PATHWAYS AND ITS TREATMENT D.M. Bowen, Department of Neurochemistry, Institute for Neurology, London, U.K.