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Biomedical subjects

B Frangione

Publications and source records attributed to B Frangione.

At least 127 records · Page 7Linked to original sources
PubMed1994

Apolipoprotein E associates with beta amyloid peptide of Alzheimer's disease to form novel monofibrils. Isoform apoE4 associates more efficiently than apoE3.

Late-onset and sporadic Alzheimer's disease are associated with the apolipoprotein E (apoE) type 4 allele expressing the protein isoform apoE4. Apolipoprotein E binds avidly to beta amyloid (A beta) peptide, a major component of senile plaque of Alzheimer's disease, in an isoform-specific manner. The apoE4 isoform binds to A beta peptide more rapidly than apoE3. We observed that soluble SDS-stable complexes of apoE3 or apoE4, formed by coincubation with A beta peptide, precipitated after several days of incubation at 37 degrees C with apoE4 complexes precipitating more rapidly than apoE3 complexes. A beta(1-28) and A beta(1-40) peptides were incubated in the presence or absence of apoE3, apoE4, or bovine serum albumin for 4 d at 37 degrees C (pH 7.3). Negative stain electron microscopy revealed that the A beta peptide alone self-assembled into twisted ribbons containing two or three strands but occasionally into multistranded sheets. The apoE/A beta coincubates yielded monofibrils 7 nm in diameter. ApoE4/A beta coincubates yielded a denser matrix of monofibrils than apoE3/A beta coincubates. Unlike purely monofibrillar apoE4/A beta coincubates, apoE3/A beta coincubates also contained double- and triple-stranded structures. Both apoE isoforms were shown by immunogold labeling to be uniformly distributed along the A beta peptide monofibrils. Monofibrils appeared earlier in apoE4/A beta than in apoE3/A beta in time-course experiments. Thus apoE3 and apoE4 each interact with beta amyloid peptide to form novel monofibrillar structures, apoE4 more avidly, a finding consistent with the biochemical and genetic association between apoE4 and Alzheimer's disease.

Alzheimer Disease↗
PubMed1994

Acceleration of Alzheimer's fibril formation by apolipoprotein E in vitro.

Numerous studies have established a linkage between the apolipoprotein (apo) E4 allele and late-onset Alzheimer's disease. It remains unclear if apo E plays a direct role in the pathogenesis of Alzheimer's disease and what, if any, are its significant interactions with amyloid beta (A beta) and tau. Apo E has been found immunohistochemically in all types of amyloid deposits and apo E fragments have been isolated from amyloid. Furthermore, apo E has been shown to bind soluble A beta. It has been proposed that apo E acts to promote and/or modulate A beta fibril formation. It is well established that peptides homologous to A beta will form amyloid-like fibrils in solution. With the use of electron microscopy and a thioflavin T assay for fibril formation we found that apo E and apo E4 in particular enhance this spontaneous fibrillogenesis of A beta peptides under the in vitro conditions used. These in vitro data suggest that the apo E4 isoform is a risk factor for Alzheimer's disease that acts to accelerate a process that can occur in its absence.

Alzheimer Disease↗
PubMed1994

Potential role of apolipoprotein-E in fibrillogenesis.

Immunohistochemical and biochemical studies have demonstrated several different proteins in amyloid deposits that are not intrinsic components of the fibril itself but may play a role in their deposition and fibril formation. We compared the distribution of several amyloid-associated proteins, ie, amyloid P component, apolipoprotein-E, apolipoprotein-J, and vitronectin, in the deposits of several different amyloids, in particular light chain amyloid, with those in the deposits of nonamyloid monoclonal immunoglobulin, which may be considered a form of preamyloid disease. Although 100% of amyloid specimens (7 amyloid A, 15 immunoglobulin light chain, and 1 transthyretin) had amyloid P component and 100% had apolipoprotein-E (2 amyloid A, 10 immunoglobulin light chain, and 1 transthyretin) co-localized with the primary amyloid protein, none of the monoclonal nonamyloid cases (14 light chain deposition disease and 6 light and heavy chain deposition disease) had amyloid P component and only 1 of 11 had apolipoprotein-E. On the other hand, staining for apolipoprotein-J and vitronectin was positive in 100% of cases of amyloid and nonamyloid monoclonal deposits. The association between the presence of apolipoprotein-E and amyloid P component in the fibrillar form of monoclonal light chain deposits and their absence in the nonfibrillar form of deposits suggest a role for these proteins in the process of fibrillogenesis. This lends support for the previously proposed concept that apolipoprotein-E functions as a pathological chaperone by altering the conformation of amyloidogenic proteins.

Amyloidosis↗
PubMed1994

Ocular amyloid deposition in familial amyloidosis, Finnish: an analysis of native and variant gelsolin in Meretoja's syndrome.

PURPOSE: To analyze the deposition of amyloid and its precursors in eyes of patients with familial amyloidosis, Finnish (FAF; Meretoja's syndrome), a hereditary systemic amyloidosis. METHODS: Autopsy eyes from three patients with FAF and ten control eyes were studied by Congo red staining and with antibodies to the nonmutated part of gelsolin (GS-2C4), the mutated gelsolin Asn-187 fragment (AGel), and amyloid-P component (AP). RESULTS: Congo red and antisera to AP and AGel bound to amyloid deposits in the cornea and conjunctiva, the sclera, the perineurium of ciliary nerves, the walls of ciliary vessels, the optic nerve sheaths, the stroma of the ciliary body, and along the choriocapillaris. mAb GS-2C4 bound weakly and focally to most deposits and strongly around the choriocapillaris. It labeled the corneal epithelium and endothelium, keratocytes, scleral fibroblasts, trabecular and lens epithelial cells, the ciliary muscle and epithelium, the iris sphincter and dilator, and stromal cells of the conjunctiva and uveal tract. CONCLUSIONS: Local production, especially in the cornea, conjunctiva, sclera, and ciliary muscle, and systemic deposition, particularly in blood vessles and in the sclera, may contribute to amyloid deposits in FAF. To explain the complex pattern of deposition, microenvironmental factors such as lamellar architecture of the cornea and sclera, altered processing of gelsolin, or blood-tissue barriers must be invoked. In addition to corneal lattice dystrophy type II, the observed deposits help to explain glaucoma in patients with FAF.

Aged↗
PubMed1993

Blood-brain barrier transport of circulating Alzheimer's amyloid beta.

The origin of amyloid beta (A beta) deposited in brain and cerebral blood vessels of patients with Alzheimer's Disease (AD) is not known. In this study, we tested whether soluble A beta (sA beta) can cross the blood-brain barrier (BBB). An in vivo vascular brain perfusion model and capillary depletion technique in guinea-pigs were used to determine cerebral capillary sequestration and blood-brain transport of a synthetic peptide identical with residues 1-40 (SP-40) of A beta. A saturable, specific binding of SP-40 has been demonstrated at the luminal side of the BBB, with the Kd of 25 +/- 2 nM, and Bmax of 188 +/- 11 fmol/min/g of isolated microvessels. A specific transcellular BBB transport of SP-40 into brain parenchyma exhibited the Km of 49 +/- 10 nM, and Vmax of 111 +/- 19 fmol/min/g of capillary depleted brain. We concluded that the BBB has the capability to control the cerebrovascular sequestration and blood-to-brain transport of circulating sA beta. Hence, sA beta can contribute to both cerebrovascular and parenchymal amyloid formation.

Amyloid beta-Peptides↗
PubMed1993

High-level expression and in vitro mutagenesis of a fibrillogenic 109-amino-acid C-terminal fragment of Alzheimer's-disease amyloid precursor protein.

We amplified DNA encoding the 3' 109 codons of Alzheimer's-disease amyloid precursor protein (APP) inclusive of the beta protein (A beta) and cytoplasmic domains from cDNA using oligonucleotide primers designed to facilitate cloning into the T7 expression vector pT7Ad23K13. We also modified this construct to generate recombinant molecules incorporating two recently described APP mutants by site-directed mutagenesis. Both native C109 (deletion construct inclusive of the C-terminal 109 residues of APP) and constructs with a single mutation at codon 642 (T-->G, resulting in a substitution of glycine for valine) or a double mutation at codons 595 (G-->T, substituting asparagine for lysine) and 596 (A-->C, substituting leucine for methionine) were expressed in Escherichia coli to levels of 5-20% of total bacterial protein after induction. The major constituent of expressed C109 protein had an apparent molecular mass of 16-18 kDa by SDS/PAGE and appeared to be the full-length construct by size and N-terminal microsequencing. Also present was a 4-5 kDa species that co-purified with C109, constituting only approximately 1% of expressed protein, which was revealed by Western-blot analysis with antibodies specific for A beta epitopes and after biotinylation of purified recombinant C109. This fragment shared N-terminal sequence with, and appeared to arise by proteolysis of, full-length C109 in biosynthetic labelling experiments. C109 spontaneously precipitated after dialysis against NaCl or water, and with prolonged (> 20 weeks) standing was found by electron microscopy to contain a minor (< 5%) fibrillar component that was reactive with antibodies to a C-terminal epitope of APP. Recombinant C109 appears to duplicate some of the biochemical and physicochemical properties of C-terminal A beta-inclusive fragments of APP that have been found in transfected cells, brain cortex and cerebral microvessels.

Alzheimer Disease↗
PubMed1993

A68 is a component of paired helical filaments of Gerstmann-Sträussler-Scheinker disease, Indiana kindred.

Gerstmann-Sträussler-Scheinker disease in the Indiana kindred is pathologically characterized by prion protein amyloid deposits and neurofibrillary tangles (NFT) with paired helical filaments (PHF). Using antibodies to various domains of the tau molecule, we investigated the composition of PHF in this family by immunocytochemistry and immunoblot analysis. The results indicate that A68 is a component of NFT in this family as it is in Alzheimer's disease, and suggest that post-translational modifications of tau leading to formation of A68 are not unique to Alzheimer's disease.

Aged↗
PubMed1993

The cerebrospinal-fluid soluble form of Alzheimer's amyloid beta is complexed to SP-40,40 (apolipoprotein J), an inhibitor of the complement membrane-attack complex.

The amyloid fibrils deposited in Alzheimer's neuritic plaque cores and cerebral blood vessels are mainly composed of aggregated forms of a unique peptide, 39-42 amino acids long, named amyloid beta (A beta). A similar, although soluble, A beta ('sA beta') has been identified in cerebrospinal fluid, plasma and cell supernatants, indicating that it is normally produced by proteolytic processing of its precursor protein, amyloid precursor protein (APP). Using direct binding experiments we have isolated and characterized an 80 kDa circulating protein that specifically interacts with a synthetic peptide identical with A beta. The protein was unmistakably identified as SP-40,40 or ApoJ, a cytolytic inhibitor and lipid carrier, by means of amino acid sequence and immunoreactivity with specific antibodies. Immunoprecipitation with anti-SP-40,40 retrieved soluble A beta from cerebrospinal fluid, indicating that the interaction occurs in vivo.

Amino Acid Sequence↗
PubMed1993

Gelsolin immunoreactivity in corneal amyloid, wound healing, and macular and granular dystrophies.

Immunohistologic studies of tissue sections obtained from patients with type 1 or type 2 lattice corneal dystrophy, polymorphic amyloid degeneration, or gelatinous amyloid degeneration were performed by using a monoclonal antibody raised to a chymotryptic fragment inclusive of the carboxy-terminal half of plasma gelsolin, and also with a series of polyclonal antibodies specific for synthetic peptides corresponding to immunogenic epitopes of gelsolin. These epitopes are parts of sequences at the amino- and carboxy-terminal ends of gelsolin, as well as adjacent to and inclusive of the codon 187 mutant 7-11 kD fragment that has been shown to be the subunit protein of amyloid fibrils occurring systemically in patients affected by Finnish type familial amyloidosis. These antibodies were also tested on tissue sections obtained from patients with granular and macular corneal dystrophy, corneal wounds, and normal control corneas. Specificity of staining was established by absorption with gelsolin purified from plasma, or the appropriate synthetic peptide. Gelsolin immunoreactivity was detected in the conjunctival and skin amyloid in familial amyloidosis by using familial amyloid (Finnish type) antibody. In other types of corneal amyloid, including lattice dystrophy type 1, immunoreactivity with gelsolin and synthetic peptides was observed adjacent to the deposits, but rarely within them. In macular dystrophy, variable staining of the deposits could result from the association of subunit proteins with glycosaminoglycans.

Amyloidosis↗
PubMed1993

Synthetic peptides corresponding to different mutated regions of the amyloid gene in familial Creutzfeldt-Jakob disease show enhanced in vitro formation of morphologically different amyloid fibrils.

We synthesized polypeptides corresponding to sequences encoded by normal and mutant alleles in the regions of codon 178 (Asp-->Asn) and codon 200 (Glu-->Lys) of the chromosome 20 amyloid gene that have been linked to familial Creutzfeldt-Jakob disease. Peptide suspensions from both regions spontaneously formed amyloid fibrils with different morphological characteristics and aggregation tendencies. Fibrillar arrays were denser and more profuse in mutant than in normal peptide suspensions and were even more marked when the homologous mutant and normal peptides were mixed together. Preparations from the region of codon 200 were in all cases more fibrillogenic than corresponding peptides from the region of codon 178. These in vitro observations support the hypothesis that amino acid changes from pathogenic single-allele point mutations in Creutzfeldt-Jakob disease may nucleate the in vivo folding behavior of the normal host protein to favor formation of insoluble amyloid fibrils.

Amino Acid Sequence↗
PubMed1993

Apolipoprotein E: binding to soluble Alzheimer's beta-amyloid.

Apolipoprotein E (apo E) is associated with Alzheimer's beta-amyloid (A beta) in senile plaques. A beta is now known to be a normal soluble peptide (sA beta) found in the cerebrospinal fluid (CSF) and other biological fluids. We have used synthetic A beta peptides bound to affinity membranes in order to determine whether apo E or any other amyloid associated protein will bind to these membranes, when they are bathed in CSF. Under these conditions apo E, as well as another apolipoprotein, apolipoprotein J (Apo J), bound to the membranes. Using ELISA and ligand binding studies, we found a high avidity binding of A beta peptides to apo E. This suggests that apo E, as well as other related proteins may bind not only amyloid A beta but also sA beta. This interaction may be critical in amyloid formation.

Alzheimer Disease↗
PubMed1993

Proteolytic processing of human amyloid beta protein precursor in insect cells. Major carboxyl-terminal fragment is identical to its human counterpart.

The predominant component of amyloid plaques of Alzheimer's disease is the amyloid beta protein (A beta), a 39-42-amino-acid peptide derived by proteolysis of a family of precursors known as amyloid precursor proteins (APP). In mammalian brain and in cultured mammalian cells, the release of APP amino-terminal fragments into the extracellular medium occurs by a proteolytic cleavage within the A beta domain, thereby precluding amyloidogenesis. Infection of Sf9 insect cells with baculovirus vectors containing APP cDNAs results in high levels of APP expression. The concomitant release of amino-terminal fragments of APP and the production of carboxyl-terminal, cell-associated cleavage products are observed. Here we demonstrate by direct protein microsequencing that the proteolytic processing of APP in the Sf9 cells generates a prominent carboxyl-terminal species that is identical to that produced in human cells, suggesting that the major pathway for proteolytic processing of APP is conserved among metazoans.

Amino Acid Sequence↗
PubMed1993

Cerebrospinal fluid inhibits Alzheimer beta-amyloid fibril formation in vitro.

Alzheimer's disease is characterized by the deposition of beta-protein (A beta) as amyloid. Recently, it was found that A beta is a normal component of serum and cerebrospinal fluid. Synthetic peptides homologous to A beta form amyloid-like fibrils spontaneously in water or physiological solutions. Using a peptide homologous to A beta 1-40, we find that fibril formation is inhibited by the presence of cerebrospinal fluid.

Alzheimer Disease↗
PubMed1993

Ubiquitinated neurites are associated with preamyloid and cerebral amyloid beta deposits in patients with hereditary cerebral hemorrhage with amyloidosis Dutch type.

Hereditary cerebral hemorrhage with amyloidosis Dutch type (HCHWA-D) is characterized clinically by recurrent strokes and pathologically by deposition of amyloid beta (A beta) in cerebral vessel walls and, to a lesser extent, in the neuropil. Distinct from Alzheimer's disease, amyloid formation in HCHWA-D is not associated with neurofibrillary changes. Since a central issue in the pathophysiology of Alzheimer's disease and related conditions is the role of A beta in the neurodegenerative process, we investigated HCHWA-D brains for the presence of neuritic abnormalities using antibodies to ubiquitin and to phosphorylated neurofilaments. The study showed that amyloid deposits in the vessel walls and in the neuropil were surrounded by abnormal ubiquitinated neurites, suggesting that A beta deposition induces neuritic changes.

Aged↗
PubMed1993

Beta PP participates in PrP-amyloid plaques of Gerstmann-Sträussler-Scheinker disease, Indiana kindred.

Gerstmann-Sträussler-Scheinker disease in the Indiana kindred is pathologically characterized by deposits of PrP-amyloid, neurofibrillary tangles and degenerating neurites. The aim of this study was to investigate seven patients of different ages for beta PP and A beta immunoreactivities associated with PrP-amyloid deposits and degenerating neurites. In one asymptomatic individual with PrP-amyloid deposits, Alz50 and A beta immunoreactivities were absent. In six symptomatic patients, the degenerating neurites surrounding PrP-amyloid deposits were labeled by Alz50 and by antibodies to synaptophysin, ubiquitin and the N- and C-terminal domains of beta PP. In one symptomatic, senile patient, A beta immunoreactivity was present in the extracellular space, often in association with PrP-amyloid deposits. The analysis of the immunohistochemical findings suggested that in the Indiana kindred the intracellular accumulation of beta PP, synaptophysin and ubiquitinated material most probably revealed a reaction of neurites to PrP-amyloid, whereas the extracellular deposition of A beta was likely an age-related phenomenon.

Aged↗
PubMed1993

Immunohistochemical analysis of lattice corneal dystrophies types I and II.

Corneal buttons from four patients with lattice corneal dystrophy (LD) type I, thought to be an isolated corneal amyloidosis, and from six patients with LD type II, part of systemic familial amyloidosis, Finnish type (FAF; Meretoja's syndrome), were studied by immunohistochemistry to determine the differential distribution in the amyloid deposits of amyloid P component (AP), mutated gelsolin specific for FAF, and native gelsolin. In both types of LD, antibodies to AP labelled lattice lines and a discontinuous layer of amyloid deposits under Bowman's layer. In LD type II, particularly, they also reacted with streak-like amyloid deposits between corneal almellae, especially in the limbal region. While the anti-FAF antiserum strongly labelled all amyloid deposits in LD type II, it failed to react unequivocally with them in LD type I. Both in LD type I and in two control specimens representing granular dystrophy, the monoclonal antibody (MAb) GS-2C4 to gelsolin faintly labelled some deposits, while in LD type II it reacted non-homogeneously with most amyloid deposits. In all specimens, MAb GS-2C4 labelled corneal epithelial cells and occasional stromal keratocytes and endothelial cells. The results suggest that Meretoja's syndrome, a systemic disease, can be diagnosed even retrospectively from corneal buttons subjected to histopathological study.

Adult↗
PubMed1992

A 109-amino-acid C-terminal fragment of Alzheimer's-disease amyloid precursor protein contains a sequence, -RHDS-, that promotes cell adhesion.

Amyloid beta (A beta), the major constituent of the fibrils composing senile plaques and vascular amyloid deposits in Alzheimer's disease (AD) and related disorders, is a 39-42-residue self-aggregating degradation peptide of a larger multidomain membrane glycoprotein designated amyloid precursor protein (APP). An array of biological functions has been assigned to different APP domains, including growth regulation, neurotoxicity, inhibitory activity of serine proteinases and promotion of cell-cell and cell-matrix interactions. A beta is generated through an as-yet-unknown catabolic pathway that by-passes or inhibits the cleavage of APP within the A beta sequence. We have identified a 16 kDa intermediate APP C-terminal fragment containing A beta in leptomeningeal vessels of aged normal individuals and AD patients by means of its immunoreactivity with a panel of four different anti-(APP C-terminal) antibodies, indicating a different pathway of APP processing. Previous studies have indicated that the APP C-terminal domain is the most likely to be involved in cell-matrix interactions. A 109-amino-acid construct C109 with a sequence analogous to the C-terminal of APP (positions 587-695 of APP695), similar in length and immunoreactivity to the 16 kDa fragment, was found to promote cell adhesion. By use of synthetic peptides, this activity was initially located to the extracellular 28 residues of A beta. Inhibition studies demonstrated that the sequence RHDS (amino acids 5-8 of A beta, corresponding to residues 601-604 of APP695 was responsible for the adhesion-promoting activity. The interaction is dependent on bivalent cations and can be blocked either by the tetrapeptides RHDS and RGDS or by an anti-(beta 1 integrin) antibody. Thus, through integrin-like surface receptors, APP or its derivative proteolytic fragments containing the sequence RHDS may modulate cell-cell or cell-matrix interactions.

Aged↗