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J Ghiso

Publications and source records attributed to J Ghiso.

At least 73 records · Page 4Linked to original sources
PubMed1996

Fate of cerebrospinal fluid-borne amyloid beta-peptide: rapid clearance into blood and appreciable accumulation by cerebral arteries.

In Alzheimer's disease, the neuritic or senile amyloid plaques in hippocampus and association cortex, the diffuse plaques in brain areas such as the cerebellum and sensorimotor cortex, and the amyloid deposits in the walls of pial and parenchymal blood vessels are mainly composed of amyloid beta-peptides. In the present study, either soluble 40-residue amyloid beta-peptide radiolabeled with 125I (I-sAbeta) or [14C]polyethylene glycol ([14C]PEG, a reference material) was briefly infused into one lateral ventricle of normal rats. By 3.5 min, 30% of the I-sAbeta was cleared from ventricular CSF into blood; another 30% was removed over the next 6.5 min. No [14C]PEG was lost from the CSF-brain system during the first 5 min, and only 20% was cleared by 10 min. Much of the I-sAbeta that reached the subarachnoid space was retained by pial arteries and arterioles. Virtually no I-sAbeta was found in brain. The clearance of amyloid beta-peptides from the CSF-brain system, reported herein for normal rats, may be reduced in Alzheimer's disease, thus contributing to amyloid deposition in cerebral tissue and blood vessels.

Amyloid beta-Peptides↗
PubMed1996

beta PP and Tau interaction. A possible link between amyloid and neurofibrillary tangles in Alzheimer's disease.

Extracellular deposition of amyloid fibrils and intraneuronal accumulation of paired helical filaments (PHFs) are the neuropathological hallmarks of Alzheimer's disease. The major constituent of amyloid fibrils is a 39- to 43-residue peptide (termed A beta), which is derived from a 695- to 770-amino-acid precursor protein (termed beta PP). The main component of PHFs identified so far is the microtubule-associated protein tau. Yet, there is no direct evidence of interconnection between these two pathological states. We report here that antibodies to an epitope located between residues 713 and 723 of beta PP770 (ie, the transmembrane region of beta PP distal to A beta) consistently labeled PHFs in the brain of Alzheimer patients. Solid phase immunoassay showed that a peptide homologous to residues 713 to 730 of beta PP770 bound tau proteins. This beta PP peptide spontaneously formed fibrils in vitro and, in the presence of tau, generated dense fibrillary assemblies containing both molecules. These data suggest that beta PP or beta PP fragments containing the tau binding site are involved in the pathogenesis of PHFs in Alzheimer's disease.

Alzheimer Disease↗
PubMed1996

Light chain cardiomyopathy. Structural analysis of the light chain tissue deposits.

Cardiomyopathy due to monoclonal light chain deposits is a complication of plasma cell disorders. The deposits may be either fibrillar as in light chain amyloid or nonfibrillar as in light chain deposition disease. The reasons for these structural differences are still unknown. We characterized the myocardial deposits by immunohistochemical examination of sections and extraction and biochemical analysis of the tissue deposits in a patient (MCM) who died of myeloma and systemic light chain deposition disease. Amino acid sequence analysis of the extracted nonfibrillar MCM kappa-light chain reveals that it belongs to the L12a germline subset of the kappa(I) protein and contains five distinctive amino acid substitutions (three in the framework region III and two in the complementarity-determining region III) that have not been reported previously in the same positions in other kappa(I) light chains. The theoretically determined isoelectric point (pI 8.21) of the MCM light chain is high compared with the low isoelectric point of other Bence Jones proteins from subjects without light chain deposition disease. The diffuse binding to basement membranes and the high isoelectric point of the MCM kappa-light chain suggest electrostatic interaction as a possible mechanism of tissue deposition. The spatial locations of the five distinctive residues and a sixth rare substitution of the MCM protein modeled on the backbone structure of REI, a kappa(I)-soluble Bence Jones light chain of known three-dimensional structure, may be responsible for protein destabilization, partial unfolding, and aggregation leading to tissue deposition.

Adult↗
PubMed1995

Characterization of apolipoprotein J-Alzheimer's A beta interaction.

The main component of Alzheimer's amyloid deposits, A beta, has been found also as a soluble (sA beta) normal constituent of biological fluids and cell culture supernatants. Whether or not sA beta is the immediate precursor of A beta, it is clear that peptides with the same amino acid sequence can have both fibrillar and non-fibrillar conformations. The interconversion mechanism from one form to another is presently under intensive investigation. We have previously described that (i) a synthetic peptide A beta 1-40 immobilized on affinity matrices was able to retrieve apolipoprotein J (apoJ) from plasma and cerebrospinal fluid; and (ii) the interaction of sA beta with apoJ occurs in vivo, as demonstrated by the ability of anti-apoJ to co-precipitate sA beta from normal cerebrospinal fluid. We have characterized the binding between A beta 1-40 and apoJ and found that the interaction is saturable, specific, and reversible. The dissociation constant of 2 x 10(-9) M is indicative of high affinity binding. The stoichiometry of the reaction is 1:1; apoJ has five times more affinity for fresh A beta 1-40 than for the aggregated peptide. Competitive inhibition studies carried out with apolipoprotein E (isoforms E2, E3, and E4), transthyretin, vitronectin, and alpha 1-antichymotrypsin indicate that the complex apoJ.A beta 1-40 cannot be dissociated by any of these competitors at physiologic concentrations. The data strongly suggest that apoJ plays an important role as a carrier protein for sA beta.

Amino Acid Sequence↗
PubMed1995

Tau protein directly interacts with the amyloid beta-protein precursor: implications for Alzheimer's disease.

The simultaneous presence of intracellular neurofibrillary tangles (NFT) and extracellular senile plaques in Alzheimer's disease (AD) suggests that the two lesions could be synergistically interrelated. However, although the main protein components of NFT and senile plaques, tau (tau) and amyloid beta-protein, respectively, are well characterized, the molecular mechanisms responsible for their deposition in lesions are unknown. We demonstrate, using four independent techniques, that tau directly interacts with a conformation-dependent domain of the amyloid beta-protein precursor (beta PP) encompassing residues beta PP714-723. The putative tau-binding domain includes beta PP717 mutation sites that are associated with familial forms of AD. Our findings strongly suggest that NFT and senile plaques, often thought of as independent structures, may play a role in each other's formation during the pathogenesis of AD.

Alzheimer Disease↗
PubMed1994

The soluble form of Alzheimer's amyloid beta protein is complexed to high density lipoprotein 3 and very high density lipoprotein in normal human plasma.

The amyloid fibrils of Alzheimer's neuritic plaques and cerebral blood vessels are mainly composed of aggregated forms of a 39 to 44 amino acids peptide, named amyloid beta (A beta). A similar although soluble form of A beta (sA beta) has been identified in plasma, cerebrospinal fluid and cell culture supernatants, indicating that it is produced under physiologic conditions. We report here that sA beta in normal human plasma is associated with lipoprotein particles, in particular to the HDL3 and VHDL fractions where it is complexed to ApoJ and, to a lesser extent, to ApoAI. This was assessed by immunoprecipitation experiments of purified plasma lipoproteins and lipoprotein-depleted plasma and confirmed by means of amino acid sequence analysis. Moreover, biotinylated synthetic peptide A beta 1-40 was traced in normal human plasma in in vitro experiments. As in the case of sA beta, biotinylated A beta 1-40 was specifically recovered in the HDL3 and VHDL fractions. This data together with the previous demonstration that A beta 1-40 is taken up into the brain via a specific mechanism and possibly as an A beta 1-40-ApoJ complex indicate a role for HDL3- and VHDL-containing ApoJ in the transport of the peptide in circulation and suggest their involvement in the delivery of sA beta across the blood-brain barrier.

Amino Acid Sequence↗
PubMed1994

Brain uptake of circulating apolipoproteins J and E complexed to Alzheimer's amyloid beta.

Amyloid beta (A beta) is a fibrillar component in Alzheimers' disease amyloid deposits and a soluble peptide (sA beta) normally present in body fluids. We have recently reported that the blood-brain barrier (BBB) has a capability to control cerebrovascular sequestration and transport of circulating sA beta. In this study, we examined whether two circulating amyloid-associated proteins shown to bind sA beta, apolipoproteins J (apo J) and E (apo E), can cross the BBB alone and/or complexed to a synthetic peptide homologous to a major form of sA beta, sA beta 1-40. Brain perfusion experiments in guinea pigs showed significant uptake of both apo J and sA beta 1-40-apo J complexes. In contrast, blood-brain transport of sA beta 1-40-apo E was negligible, while apo E had a limited access across the BBB, indicating that the apo E found within the brain is produced locally. It is concluded that sA beta 1-40 binding to apo J and apo E results in significant (> 100-fold) difference in brain uptake of their respective complexes. We hypothesize that in normal brain apo J facilitates sA beta transport.

Amyloid beta-Peptides↗
PubMed1994

Characterization of a novel processing pathway for Alzheimer's amyloid beta precursor protein.

Amyloid beta (A beta) is a normal proteolytic fragment of a large precursor protein (beta PP) which undergoes altered conformation, leading to fibril formation. Two main beta PP processing pathways have been described, and we are now reporting the characterization of a third beta PP pathway. A membrane-associated 16 kDa component identified in human platelets isolated from normal donors. Based on size, immunoreactivity and amino acid sequence analysis, the fragment is a C-terminal beta PP component which starts at position 642 (APP770 numbering) and contains the intact A beta sequence. The presence of this novel pathway of beta PP processing in resting platelets suggest that it occurs as a normal event.

Alzheimer Disease↗
PubMed1994

Unifying features of systemic and cerebral amyloidosis.

Amyloidosis is a generic term for a group of clinically and biochemically diverse diseases that are characterized by the deposition of an insoluble fibrillar protein in the extracellular space. Over 16 biochemically distinct amyloids are known. Despite this diversity, all amyloids have a particular ultrastructural and tinctorial appearance, a beta-pleated sheet structure, and are codeposited with a group of amyloid-associated proteins. The most common amyloidosis is Alzheimer's disease (AD), where A beta is the main component of the amyloid. Recently it has been found that A beta exists as a normal soluble protein (sA beta) in biological fluids. This links AD more closely to some of the systemic amyloidoses, where the amyloid precursor is found in the circulation normally. Numerous mutations have been found in the A beta precursor (beta PP) gene, associated with familial AD. Many mutations are also found in some of the hereditary systemic amyloidoses. For example, over 40 mutations in the transthyretin (TTR) gene are associated with amyloid. However, both A beta and TTR related amyloid deposition can occur with no mutation. The pathogenesis of amyloid is complex, and appears to be associated with genetic and environmental risk factors that can be similar in the systemic and cerebral amyloidoses.

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

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

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↗