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Biomedical subjects

B Frangione

Publications and source records attributed to B Frangione.

At least 73 records · Page 4Linked to original sources
PubMed1997

Amino-terminal identity of co-existent amyloid and non-amyloid immunoglobulin kappa light chain deposits. A human disease to study alterations of protein conformation.

Tissue deposition of monoclonal immunoglobulin light chains is a serious complication in some patients with B cell proliferative disorders. The deposits are typically fibrillar and Congophilic in amyloid (AL) and non-fibrillar and Congophobic in light chain deposition disease (LCDD), and rarely coexist in the same patient. From post-mortem tissue of an individual with fibrillar and non-fibrillar kappa light chain deposits in different sites, we separately extracted and analysed biochemically and immunochemically the non-amyloid deposits from isolated glomeruli, the amyloid from isolated renal arteries and the amyloid from myocardium in which the only deposits were amyloid restricted to mural arteries. Western blotting analysis of both the extracted amyloid and the non-amyloid deposits demonstrated 25-kD bands immunoreactive with anti-kappa antibody, and the identity of the N-terminal amino acid sequences that belong to the variable region kappaIV light chain subgroup. This is the first human disease in which antigenically similar but morphologically different deposits have been separately biochemically analysed. We propose that combined LCDD and AL is an ideal human disease to study the relationships and the factors that influence the conversion of non-amyloidogenic to amyloidogenic conformations.

Aged↗
PubMed1997

Isoform-specific effects of apolipoproteins E2, E3, and E4 on cerebral capillary sequestration and blood-brain barrier transport of circulating Alzheimer's amyloid beta.

Cerebral capillary sequestration and blood-brain barrier (BBB) permeability to apolipoproteins E2 (apoE2), E3 (apoE3), and E4 (apoE4) and to their complexes with sA beta(1-40), a peptide homologous to the major form of soluble Alzheimer's amyloid beta, were studied in perfused guinea pig brain. Cerebrovascular uptake of three apoE isoforms was low, their blood-to-brain transport undetectable, but uptake by the choroid plexus significant. Binding of all three isoforms to sA beta(1-40) in vitro was similar with a K(D) between 11.8 and 12.9 nM. Transport into brain parenchyma and sequestration by BBB and choroid plexus were negligible for sA beta(1-40)-apoE2 and sA beta(1-40)-apoE3, but significant for sA beta(1-40)-apoE4. After 10 min, 85% of sA beta(1-40)-apoE4 taken up at the BBB remained as intact complex, whereas free sA beta(1-40) was 51% degraded. Circulating apoE isoforms have contrasting effects on cerebral capillary uptake of and BBB permeability of sA beta. ApoE2 and apoE3 completely prevent cerebral capillary sequestration and blood-to-brain transport of sA beta(1-40). Conversely, apoE4, by entering brain microvessels and parenchyma as a stable complex with sA beta, reduces peptide degradation and may predispose to cerebrovascular and possibly enhance parenchymal amyloid formation under pathological conditions.

Amino Acid Sequence↗
PubMed1997

Proteinases secreted by Fasciola hepatica degrade extracellular matrix and basement membrane components.

The invasive stages of the parasitic trematode Fasciola hepatica release proteinases into the medium in which they are maintained. In this study, we investigated the interaction of F. hepatica excretory/secretory (E/S) products and 2 cysteine proteinases (CL1 and CL2) purified from these products with extracellular matrix and basement membrane macromolecules. Fasciola hepatica E/S products contained collagenolytic activity on fibrillar types I and III collagen as well as basement membrane type IV collagen. CL1 and CL2 were capable of degrading acid-soluble type III and type IV collagen but not insoluble type I collagen. In contrast, neither the E/S products nor the purified CL1 and CL2 showed elastinolytic activity. Fibronectin and laminin were degraded by E/S products and by CL1 and CL2. Sequence analysis of fibronectin degradation products showed that the fragments obtained corresponded to complete biologically active domains. These results indicate that the cysteine proteinases secreted by F. hepatica may be involved in the process of tissue invasion by the parasite.

Amino Acid Sequence↗
PubMed1997

Presenilin-1 is associated with Alzheimer's disease amyloid.

Mutations in presenilin (PS)-1 and -2, located on chromosome 14 and 1 respectively, are the major association with early-onset familial Alzheimer's disease (FAD). FAD has also been linked to mutations in the amyloid beta precursor protein (beta PP), and the presence of the apolipoprotein E4 allele is a risk factor for late-onset AD. The role of PS in FAD and in sporadic AD is unclear. We previously reported the presence of a PS-1 carboxyl-terminal epitope in neuritic plaques (Wisniewski T, Palha JA, Ghiso J, Frangione B: S182 protein in Alzheimer's disease neuritic plaques. Lancet 1995, 346:1366). In the present study, we examined a number of biochemically different cerebral and systemic amyloidoses, finding the PS-1 carboxy epitope only in association with amyloid beta (A beta) lesions. We confirm the presence of this epitope ultrastructurally in neuritic plaques. In addition, biochemical and amino acid sequence data are presented for an association of the 18-kd carboxy fragment of PS-1 with neuritic plaques with a start at residue 300. Three of the proteins with linkage to AD have now been found as components of neuritic plaques. It remains to be determined whether all of these proteins are involved in the same or different pathological pathway(s) and which of these proteins is the most important for the common, late-onset form of AD.

Adult↗
PubMed1996

The "nonamyloidogenic" p3 fragment (amyloid beta17-42) is a major constituent of Down's syndrome cerebellar preamyloid.

Down's syndrome (DS) patients show accelerated Alzheimer's disease (AD) neuropathology, which consists of preamyloid lesions followed by the development of neuritic plaques and neurofibrillary tangles. The major constituents of preamyloid and neuritic plaques are amyloid beta (Abeta) peptides. Preamyloid lesions are defined as being Abeta immunoreactive lesions, which unlike neuritic plaque amyloid are Congo red-negative and largely nonfibrillar ultrastructurally. DS patients can develop extensive preamyloid deposits in the cerebellum, without neuritic plaques; hence, DS cerebellums are a source of relatively pure preamyloid. We biochemically characterized the composition of DS preamyloid and compared it to amyloid in the neuritic plaques and leptomeninges in the same patients. We found that Abeta17-42 or p3 is a major Abeta peptide of DS cerebellar preamyloid. This 26-residue peptide is also present in low quantities in neuritic plaques. We suggest that preamyloid can now be defined biochemically as lesions in which a major Abeta peptide is p3.

Alzheimer Disease↗
PubMed1996

The length of amyloid-beta in hereditary cerebral hemorrhage with amyloidosis, Dutch type. Implications for the role of amyloid-beta 1-42 in Alzheimer's disease.

In hereditary cerebral hemorrhage with amyloidosis, Dutch type (HCHWA-D), a genetic variant (E22Q) of amyloid beta (Abeta) accumulates predominantly in the small vessels of leptomeninges and cerebral cortex, leading to fatal strokes in the fifth or sixth decade of life. Abeta deposition in the neuropil occurs mainly in the form of preamyloid, Congo red negative deposits, while mature neuritic plaques and neurofibrillary tangles, hallmark lesions in Alzheimer's disease (AD), are characteristically absent. A recent hypothesis regarding the pathogenesis of AD states that Abeta extending to residues 42-43 (as opposed to shorter species) can seed amyloid formation and trigger the development of neuritic plaques followed by neuronal damage in AD. We characterized biochemically and immunohistochemically Abeta from three cases of HCHWA-D to determine its length in vascular and parenchymal deposits. Mass spectrometry of formic acid-soluble amyloid, purified by size-exclusion gel chromatography, showed that Abeta 1-40 and its carboxyl-terminal truncated derivatives were the predominant forms in leptomeningeal and cortical vessels. Abeta 1-42 was a minor component in these amyloid extracts. Immunohistochemistry with antibodies S40 and S42, specific for Abeta ending at Val-40 or Ala-42, respectively, were consistent with the biochemical data from vascular amyloid. In addition, parenchymal preamyloid lesions were specifically stained with S42 and were not labeled by S40, in agreement with the pattern reported for AD, Down's syndrome, and aged dogs. Our results suggest that in HCHWA-D the carboxyl-terminal Abeta heterogeneity is due to limited proteolysis in vivo. Moreover, they suggest that Abeta species ending at Ala-42 may not be critical for the seeding of amyloid formation and the development of AD-like neuritic changes.

Alzheimer Disease↗
PubMed1996

Inhibition of Alzheimer's amyloidosis by peptides that prevent beta-sheet conformation.

Amyloid beta-peptide (A beta) is a major fibrillar component of neuritic plaques in Alzheimer's disease (AD) brains and is related to the pathogenesis of the disease. We hypothesized that amyloid formation could be inhibited by peptides homologous to A beta (position 17-21) with a similar degree of hydrophobicity, but with a very low propensity to adopt a beta-sheet conformation by incorporating proline residues (anti-beta-sheet peptides or beta-sheet inhibitors). An 11-residue peptide with these characteristics binds to A beta, inhibits A beta fibril formation and partially disaggregates preformed fibrils in vitro. Shorter anti-beta-sheet peptides and analogs containing D-amino acids are also able to inhibit A beta fibrillogenesis. The latter are more resistant to proteolytic degradation and may serve as a starting point to design more efficient peptides derivatives to inhibit amyloidogenesis in vivo.

Alzheimer Disease↗
PubMed1996

Alzheimer's presenilin 1 gene expression in platelets and megakaryocytes. Identification of a novel splice variant.

The presenilin 1 (PS1) gene located on chromosome 14 has been linked with the majority of early-onset FAD. The normal biological role of PS1 as well as the mechanism by which mutations in PS1 cause FAD remains unknown. PS1 expression in platelets and the Dami megakaryocytic cell line was examined by Western blot analysis and RT-PCR. Using an anti-N-terminus PS1 antibody we detected PS1 immunoreactive bands of 44, 32 and 27 kDa in both cell types. After RT-PCR we observed that platelets and megakaryocytes carry at least four different PS1 transcripts. One of them is a novel PS1 splice variant that lacks the coding sequence for exon 10 resulting in a shorter 409 amino acid protein.

Alternative Splicing↗
PubMed1996

PrP27-30 is a normal soluble prion protein fragment released by human platelets.

Prion diseases are neurodegenerative disorders characterized by the accumulation of abnormal isoforms of prion protein (PrPSc) in the central nervous system. PrPSc isoforms differ from their normal homologue (PrPC), in that they possess increased beta-sheet conformation, are partially protease resistant and may be associated with amyloid deposition. Amyloid proteins are thought to derive from soluble precursors or fragments thereof, present in biological fluids, which in the disease state undergo conformational change leading to aggregation and deposition in target tissues. We report here that platelets carry PrP mRNA and release PrPC, a sialoglycoprotein bound to the cell surface by a glycosylphosphatidylinositol (GPI) anchor. Soluble PrPC, and a N-terminal truncated PrPC isoform starting at position 90 are secreted by resting and agonist-stimulated platelets and are detectable after partial deglycosylation of releasates. N-terminal sequence analysis of the soluble 27-30 kDa isoform, GQGGGTHSQ(W)NKP, revealed homology to scrapie PrP27-30, the protease resistant core derived from PrPSc. These findings indicate that in addition to PrPC, platelets process a soluble PrP27-30 isoform. Whether this isoform can be converted in scrapie PrP27-30 remains to be determined.

Amino Acid Sequence↗
PubMed1996

Apolipoprotein J and Alzheimer's amyloid beta solubility.

Apolipoprotein J (apoJ) has been found associated with soluble amyloid beta (sA beta) in plasma and cerebrospinal fluid in normal individuals and co-deposited with fibrillar A beta in Alzheimer's cerebrovascular and parenchymal lesions. Although studies in vitro and in vivo indicate that apoJ is a major carrier protein for sA beta, its role in the fibrillogenesis process is not known. We report herein that apoJ in its native high-density lipoprotein lipidic environment is fully active to interact with A beta peptides. Furthermore, apoJ prevents aggregation and polymerization of synthetic A beta in vitro. The interaction was stable for at least 14 days at 37 degrees C in physiologic buffers, and the peptide retrieved after complex dissociation at low pH retained its inherent aggregation properties. In addition, the binding to apoJ protects synthetic A beta from proteolytic degradation; both A beta 1-42 and A beta 1-40 were more resistant to proteolysis by trypsin and chymotrypsin when complexed to apoJ. The data suggest that the interaction may preclude sA beta aggregation in biological fluids and point to a protecting role of apoJ for complexed A beta species.

Alzheimer Disease↗
PubMed1996

Glycoprotein 330/megalin: probable role in receptor-mediated transport of apolipoprotein J alone and in a complex with Alzheimer disease amyloid beta at the blood-brain and blood-cerebrospinal fluid barriers.

A soluble form of Alzheimer disease amyloid beta-protein (sA beta) is transported in the blood and cerebrospinal fluid mainly complexed with apolipoprotein J (apoJ). Using a well-characterized in situ perfused guinea pig brain model, we recently obtained preliminary evidence that apoJ facilitates transport of sA beta (1-40)-apoJ complexes across the blood-brain barrier and the blood-cerebrospinal fluid barrier, but the mechanisms remain poorly understood. In the present study, we examined the transport process in greater detail and investigated the possible role of glycoprotein 330 (gp330)/megalin, a receptor for multiple ligands, including apoJ. High-affinity transport systems with a Km of 0.2 and 0.5 nM were demonstrated for apoJ at the blood-brain barrier and the choroid epithelium in vivo, suggesting a specific receptor-mediated mechanism. The sA beta (1-40)-apoJ complex shared the same transport mechanism and exhibited 2.4- to 10.2-fold higher affinity than apoJ itself. Binding to microvessels, transport into brain parenchyma, and choroidal uptake of both apoJ and sA beta (1-40)-apoJ complexes were markedly inhibited (74-99%) in the presence of a monoclonal antibody to gp330/megalin and were virtually abolished by perfusion with the receptor-associated protein, which blocks binding of all known ligands to gp330. Western blot analysis of cerebral microvessels with the monoclonal antibody to gp330 revealed a protein with a mass identical to that in extracts of kidney membranes enriched with gp330/megalin, but in much lower concentration. The findings suggest that gp330/megalin mediates cellular uptake and transport of apoJ and sA beta (1-40)-apoJ complex at the cerebral vascular endothelium and choroid epithelium.

Amino Acid Sequence↗
PubMed1996

Transthyretin gene in Alzheimer's disease patients.

Amyloid beta (Abeta) is known to be the main component of Alzheimer's disease (AD) senile plaques. A homologous peptide is a normal component of biological fluids and is called soluble Abeta (sAbeta). Synthetic peptides homologous to Abeta form amyloid-like fibrils in vitro. This fibril formation can be inhibited by normal human cerebrospinal fluid (CSF) [Wisniewski et al., Ann. Neurol. 34 (1993)]. Furthermore, it has been proposed that normal transthyretin (TTR), which is a component of CSF, can itself bind sAbeta, preventing amyloid fibril formation, and that variants of TTR could be associated with AD [Schwarzman et al., Proc. Natl. Acad. Sci. USA, 91 (1994)]. Because of this possible association, we screened for TTR mutations from 47 sporadic and 19 early-onset familial AD patients using single strand conformation polymorphism analysis. Our results show no correlation between TTR variants and Alzheimer's disease in this group of patients.

Age of Onset↗
PubMed1996

HB-GAM is a cytokine present in Alzheimer's and Down's syndrome lesions.

The distribution of heparin binding growth associated molecule (HB-GAM) in the cerebral amyloidoses of Alzheimer's disease (AD) and Down's syndrome (DS), conditions characterized by the deposition of amyloid beta (A beta), was investigated immunohistochemically. Antibodies to HB-GAM, a cytokine which plays an important role in brain development and maturation, showed strong immunoreactivity with senile plaques in both AD and DS. Anti-HB-GAM reacted with pre-amyloid lesions, but only when markers of dystrophic neurites were present. The presence of HB-GAM in AD brains, but not in control brains, was confirmed by Western blotting. We suggest that the presence of HB-GAM in A beta lesions is a marker of neuronal injury.

Adolescent↗
PubMed1996

Cerebrovascular amyloidosis in squirrel monkeys and rhesus monkeys: apolipoprotein E genotype.

Some neuropathological changes characteristic of aging and Alzheimer's disease (AD) in humans are present also in senescent non-human primates. The human apoE4 allele is associated with an increased risk of developing late-onset familial and sporadic AD. We found that rhesus monkeys and three subspecies of squirrel monkeys are homozygous for apoE phenotype with arginine at positions 112 and 158 as in human apoE4. However, in both species threonine replaces arginine at position 61 of human apoE. It was previously shown that arginine 61 was critical in determining apoE4 lipoprotein distribution in humans.

Alzheimer Disease↗
PubMed1996

Vascular variant of prion protein cerebral amyloidosis with tau-positive neurofibrillary tangles: the phenotype of the stop codon 145 mutation in PRNP.

Deposition of PrP amyloid in cerebral vessels in conjunction with neurofibrillary lesions is the neuropathologic hallmark of the dementia associated with a stop mutation at codon 145 of PRNP, the gene encoding the prion protein (PrP). In this disorder, the vascular amyloid in tissue sections and the approximately 7.5-kDa fragment extracted from amyloid are labeled by antibodies to epitopes located in the PrP sequence including amino acids 90-147. Amyloid-laden vessels are also labeled by antibodies against the C terminus, suggesting that PrP from the normal allele is involved in the pathologic process. Abundant neurofibrillary lesions are present in the cerebral gray matter. They are composed of paired helical filaments, are labeled with antibodies that recognize multiple phosphorylation sites in tau protein, and are similar to those observed in Alzheimer disease. A PrP cerebral amyloid angiopathy has not been reported in diseases caused by PRNP mutations or in human transmissible spongiform encephalopathies; we propose to name this phenotype PrP cerebral amyloid angiopathy (PrP-CAA).

Adult↗
PubMed1996

Amyloid beta 1-42 deposits do not lead to Alzheimer's neuritic plaques in aged dogs.

In alzheimer's disease, amyloid beta (A beta) is deposited in senile plaques and amyloid angiopathy. Longer A beta peptides, which extend to residue 42 (A beta 42), have been suggested to be critical for the seeding of amyloid. Aged dogs develop cerebral vessel amyloid and parenchymal preamyloid lesions. Preamyloid in humans is related to senile plaques, whereas in dogs such progression is rare. We evaluated the composition of aged canine vessel amyloid and preamyloid both biochemically and immunohistochemically. The vessel amyloid extended mainly to residue 40 (A beta 40), while preamyloid contained a mixture of A beta 17-42 and A beta 42, with minimal A beta 40. Our results suggest other factors besides A beta 42 are important for neuritic plaque formation.

Aging↗
PubMed1996

Apolipoprotein E and amyloidogenesis.

Alzheimer's amyloid beta-protein (A beta) is a modified, pathogenic form of a constitutive host protein, soluble amyloid beta-protein (sA beta). Both are conformational isomers encoded by the gene for the beta-amyloid precursor protein (APP), located on chromosome 21. sA beta and A beta have identical sequence but are thought to differ in their secondary structure and physicochemical properties, hence they are conformational isomers. sA beta is easily degraded, while A beta is particularly resistant. A beta has a high beta-pleated sheet content, while sA beta is thought to be more random-coil and/or alpha-helical. A beta, unlike sA beta, adopts an amyloidogenic conformation, forms aggregates and gives rise to fibrils. Most early-onset forms of Alzheimer's disease (AD) have been linked to mutations of the presenilin 1, presenilin 2 or APP genes, located on chromosomes 14, 1 and 21, respectively. Their relationship to amyloidogenesis is being investigated. On the other hand, the major risk factor for the most common form, sporadic and familial late-onset AD, is the presence of the apoE epsilon 4 allele. Recent studies have shown that a 10 kDa C-terminal fragment of apoE is complexed to A beta in neuritic plaques and that apoE isoforms can modulate amyloid formation in vitro. Moreover, thrombin cleavage of apoE generates a similar C-terminal fragment that can form amyloid-like fibrils. Thus neuritic plaques may contain both A beta and apoE amyloid fibrils. AD can be neuropathologically defined by the presence of several interacting proteins that can adopt an amyloidogenic conformation. This has led us to hypothesize that in AD, amyloidosis may be reactive rather than causative.

Alzheimer Disease↗