WorldWideScience
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Serum amyloid A protein in amyloidosis, rheumatic, and neoplastic diseases  

International Nuclear Information System (INIS)

Serum levels of amyloid protein A (SAA) have been shown to be elevated in different types of amyloidosis and in rheumatic diseases by radioimmunoassay using 125 iodine labeled AA and anti-AA. SAA levels were elevated in both primary and secondary amyloidosis, but there were highly significant differences between these levels. In heredofamilial amyloid, SAA levels were within normal limits. While the mean SAA level was elevated in persons over 70 years, the fact that some persons in this age group had normal levels suggested that marked elevation after age 70 may be due to occult inflammatory or neoplastic disease. High SAA levels in patients with rheumatoid arthritis correlated, in most cases, with physician evaluation of disease activity and Westergren ESR. SAA levels in patients with systemic lupus erythematosus were lower than those in patients with rheumatoid arthritis, and most patients with degenerative joint disease had normal levels. Very high levels of SAA were found in patients with neoplastic diseases. Patients with carcinoma of the lung and bowel had much higher levels than patients with carcinoma of the breast. Determination of SAA levels may be of value in evaluating different forms of systemic amyloidosis, assessing the activity of rheumatic disease, and screening for occult inflammatory or neoplastic disease

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A comparison of serum amyloid A (SAA) synthesis with that of the pentraxins: Serum amyloid P (SAP) and C-reactive protein (CRP)  

International Nuclear Information System (INIS)

Serum amyloid A (SAA) and serum amyloid P (SAP) were detected in cultures of hepatocytes which had been isolated from normal CBA/J mice by the collagenase perfusion technique. SAP production in 24 h cultures was more resistant than SAA and total protein synthesis to inhibition by actinomycin D, but was more sensitive to inhibition by 48 h. However, the production of SAP was more sensitive to cycloheximide than SAA and total protein throughout the 48 hr incubation period. SAP and SAA levels in the culture media were suppressed by treatment of liver cells with 10-6 M of colchicine for 48 h. Inhibition of SAP production by colchicine was the same regardless of culture condition, but the effect of colchicine on SAA synthesis varied according to the presence of serum of monokine. These observations also support the concept that the two amyloid proteins are produced under different regulatory mechanisms. When C-reactive protein (CRP) was not detected in the sera of patients with severe chronic liver diseases, the SAA levels were very low. When CRP was detected, SAA values were within the normal range. Thus, in order to produce SAA, liver cells in these patients not only were viable but also maintained their specialized function

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Effect of colchicine on the acute phase serum amyloid A protein response and splenic amyloid deposition during experimental murine inflammation  

International Nuclear Information System (INIS)

We investigated the effects of colchicine on the acute phase serum amyloid A protein (SAA) response and splenic amyloid A protein (AA) deposition in CBA/J mice undergoing chronic inflammatory stimulation with silver nitrate (AgNO3), and on accelerated amyloid deposition induced by amyloidenhancing factor (AEF). Colchicine (10 microg daily) significantly lowered splenic AA levels after 25 days of inflammation, as determined by radioimmunoassay. Pretreatment (3 days) with colchicine decreased SAA levels 24 h after AgNO3. It was (unexpectedly) observed that brief pretreatment (12 h) with colchicine augmented the acute phase SAA response to AgNO3 at 24 h. Colchicine stimulated production of both the SAA inducer and lymphocyte-activating factor (LAF) activities of interleukin 1 (IL 1) by macrophages. Decreased SAA levels did not appear to be the mechanism by which colchicine inhibited amyloidosis, since SAA levels fell both in colchicinetreated and control mice after 25 days of inflammation. Colchicine only partially lowered AA deposition after injection of AEF. This effect could be explained by decreased acute phase SAA levels. It is postulated that colchicine inhibits amyloidosis in the pre-deposition period by altering the production of factors (e.g., AEF) required in the deposition phase

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Acute phase proteins with special reference to C-reactive protein and related proteins (pentaxins) and serum amyloid A protein.  

Science.gov (United States)

The acute phase response among plasma proteins is a normal response to tissue injury and is therefore a fundamental aspect of many diverse disease processes. It probably usually has a beneficial net function in limiting damage and promoting repair but in some circumstances it may have pathological consequences. Sustained high levels of acute phase proteins and especially SAA are associated with the development of amyloidosis in some individuals. Increased concentrations of CRP may, by activating the complement system, contribute to inflammation and enhance tissue damage. Failure of the normal or appropriate CRP response may also possibly have deleterious effects. SAA is a polymorphic protein which is normally present only in trace amounts but which, during the acute phase response, becomes one of the major apolipoproteins associated with high-density lipoprotein particles. The function of apoSAA is not known but it must have considerable physiological significance apart from its role as the putative precursor of amyloid A protein fibrils. CRP and SAP have been very stably conserved throughout vertebrate evolution and homologous proteins are apparently present even in vertebrates. This strongly suggests that they have important functions although these have not yet been precisely delineated. The main role of CRP may be to provide for enhanced clearance of inappropriate materials from the plasma whether these are of extrinsic origin, such as microorganisms and their products, or the autologous products of cell damage and death. The interaction between aggregated CRP and plasma low-density lipoprotein may play a significant part in the normal function of CRP and may also have a role in lipoprotein metabolism, clearance, and deposition. SAP is a normal tissue protein as well as being a plasma protein. Aggregated SAP selectively binds fibronectin and this may represent an aspect of the normal function of SAP. The deposition of SAP in amyloid is evidently not a normal function but it is not known whether this deposition is involved in the pathogenesis of amyloid or whether it is merely an epiphenomenon. In any case immunohistochemical staining for SAP is useful in the diagnosis of amyloid, in investigation of glomerulonephritis, and in studying disorders of elastic tissue. Regardless of its physiological or pathophysiological functions, the assay of serum CRP is a valuable aid to clinical management in a number of different situations and in different diseases provided results are interpreted in the light of full clinical information.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:6356809

Pepys, M B; Baltz, M L

1983-01-01

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Medicated rat serum containing Gengnianchun decoction reduces apoptosis of pheochromocytoma cells insulted by amyloid beta protein  

Directory of Open Access Journals (Sweden)

Full Text Available Objective: To investigate the effects of medicated rat serum containing Gengnianchun (GNC decoction and its protection to pheochromocytoma cells (PC12 cells from amyloid beta (A?25-35-insulted apoptosis and to find the possible mechanism.Methods: Medicated rat serum was prepared by administering ovariectomized Sprague-Dawley (SD rats with GNC decoction. The effects of medicated rat serum on viability of PC12 cells were evaluated by cell counting kit-8 (CCK-8 assay. The PC12 cells were cultured with different doses of A?25-35 to induce a model of Alzheimer's disease in vitro. Then, the protective effects of medicated rat serum on A?25-35-insulted PC12 cells were evaluated by using CCK-8 assay to detect the cell viability, using Annexin ?-fluorescein isothiocyanate (FITC/propidium iodide (PI flow cytometry to detect cell apoptosis rate and using Western blotting assay to analyze the expressions of Bcl-2, Bax and active caspase-3 proteins.Results: PC12 cells cultured with 20% medicated rat serum containing GNC decoction for 24 h or 48 h had higher viability than those cultured with normal culture medium (P<0.05. After 24- or 48-hour treatment of different concentrations of A?25-35, cell viabilities were all decreased as compared with normal medium (P<0.05. Cells underwent apoptosis, which showed the neurotoxicity of A?25-35. The cell apoptosis induced by A?25-35 was significantly decreased in PC12 cells which were pretreated with 20% medicated rat serum or nerve growth factor (NGF according to CCK-8 assay and Annexin ?-FITC/PI flow cytometry (P<0.05. The ratio of Bax expression to Bcl-2 expression and the expression of active caspase-3 were decreased in the cells treated with medicated serum or NGF as compared with the cells cultured with A?25-35 only.Conclusion: The GNC-medicated rat serum at concentration of 20% can promote viability of A?25-35-insulted PC12 cells and decrease the cell apoptosis by regulating the expressions of Bcl-2, Bax and active caspase 3.

Jun LI

2010-05-01

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STIMULATED PLATELETS RELEASE AMYLOID ?–PROTEIN PRECURSOR  

OpenAIRE

Human platelets can be stimulated by thrombin or ionomycin to secrete soluble truncated amyloid ?–protein precursor and particulate membrane fragments which contain C-terminal and N-terminal immunoreactive amyloid ?–protein precursor. This suggests a possible circulating source of ?–protein in serum which may play a role in the formation of amyloid deposits. The release of soluble amyloid ?-protein precursor could be involved in normal platelet physiology.

Cole, Gregory M.; Galasko, Douglas; Shapiro, I. Paul; Saitoh, Tsunao

1990-01-01

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Influence of Polymorphism on Glycosylation of Serum Amyloid A4 Protein  

OpenAIRE

Serum amyloid A4 (SAA4) is a constitutive apolipoprotein of high-density lipoprotein. It exhibits N-linked glycosylation in its second half. There are both glycosylated and nonglycosylated forms in plasma and the ratio of these two forms varies among individuals. This study was conducted to examine the influence of genetic polymorphism of SAA4 on its glycosylation status. In 55 healthy subjects, SAA4 polymorphism was analyzed by PCR combined direct sequencing and its glycosylation status was ...

Toshiyuki Yamada; Jyunji Sato; Kazuhiko Kotani; Masafumi Tanaka

2014-01-01

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SERUM ANALYSIS OF AMYLOID BETA-PROTEIN 1-40 IN HEALTHY SUBJECTS, AUTISTIC CHILDREN AND ALZHEIMER’S PATIENTS  

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Full Text Available Amyloid beta-protein1-40 (AP40 is a low molecu­lar weight peptide produced throughout life during normal cell metabolism and neurodegenerative diseases. Owing to its neurotrophic and neurotoxic effects, the present study was conducted to evalu­ate serum levels of AP40 in healthy subjects, au­tistic children and Alzheimer’s disease patients. Serum AP40 was measured by enzyme-linked im­munosorbent assay (ELISA. AP40 was signifi­cantly higher in normal children compared to nor­mal older controls, in normal children compared to autistic children, and in autistic children compared to Alzheimer’s patients (p value was less than 0.05 for all groups. This finding suggests an age-re­lated decline of serum AP40 in normal aging, as well as in autism and Alzheimer’s disease. This decline may result from abnormal processing of amyloid beta-protein precursor (APP during nor­mal aging and age-related diseases such as autism in children and Alzheimer’s disease in elderly. Possible explanations for this decline may include age-related increased interactions of AP40 with cytoskeletal proteins for brain tissue deposition, increased serine proteases for APP metabolism or hyperimmune reaction (antibodies to AP40 for removal of circulating AP40. To conclude, the AP40 metabolism declines with normal aging and in addition to its role in Alzheimer’s disease this protein might also be a contributing factor in au­tism.

Vijendra K. SINGH

2008-06-01

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Nanophotonics of protein amyloids  

Science.gov (United States)

Technological breakthroughs in the super-resolution optical imaging techniques have enriched our current understanding of a range of biological systems and biomolecular processes at the nanoscopic spatial resolution. Protein amyloids are an important class of ordered protein assemblies consisting of misfolded proteins that are implicated in a wide range of devastating human diseases. In order to decipher the structural basis of the supramolecular protein assembly in amyloids and their detrimental interactions with the cell membranes, it is important to employ high-resolution optical imaging techniques. Additionally, amyloids could serve as novel biological nanomaterials for a variety of potential applications. In this review, we summarize a few examples of the utility of near-field scanning optical imaging methodologies to obtain a wealth of structural information into the nanoscale amyloid assembly. Although the near-field technologies were developed several decades ago, it is only recently that these methodologies are being applied and adapted for amyloid research to yield novel information pertaining to the exciting nanoscopic world of protein aggregates. We believe that the account on the nanophotonics of amyloids described in this review will be useful for the future studies on the biophysics of amyloids.

Bhattacharya, Mily; Mukhopadhyay, Samrat

2014-04-01

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Comparison of serum amyloid A and C-reactive protein as diagnostic markers of systemic inflammation in dogs  

DEFF Research Database (Denmark)

The diagnostic performance of canine serum amyloid A (SAA) was compared with that of C-reactive protein (CRP) in the detection of systemic inflammation in dogs. Sera from 500 dogs were retrospectively included in the study. C-reactive protein and SAA were measured using validated automated assays. The overlap performance, clinical decision limits, overall diagnostic performance, correlations, and agreement in the clinical classification between these 2 diagnostic markers were compared. Significantly higher concentrations of both proteins were detected in dogs with systemic inflammation (SAA range: 48.75 to > 2700 mg/L; CRP range: 0.4 to 907.4 mg/L) compared to dogs without systemic inflammation (SAA range: 1.06 to 56.4 mg/L; CRP range: 0.07 to 24.7 mg/L). Both proteins were shown to be sensitive and specific markers of systemic inflammation in dogs. Significant correlations and excellent diagnostic agreement were observed between the 2 markers. However, SAA showed a wider range of concentrations and a significantly superior overall diagnostic performance compared with CRP.

Christensen, Michelle BrØnniche; Langhorn, Rebecca

2014-01-01

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Serum amyloid-A in Behçet's disease.  

Science.gov (United States)

Serum amyloid-A (SAA) is an acute phase protein, synthesized by the liver and previously investigated as a marker of disease activity in many rheumatologic disorders. Its significance in Behçet’s disease (BD), a chronic inflammatory disorder at the crossroad between autoimmune and autoinflammatory syndromes, is still unraveled. Our aim was to assess the role of SAA levels as a potential marker of disease activity in patients with BD. According to our findings, the occurrence of oral aphthosis, neurological impairment, and ocular disease is significantly associated with SAA serum levels higher than 30, 50, and 150 mg/L, respectively. We also suggest that increased SAA levels might identify a thrombotic risk in BD with previous or concurrent vascular involvement. PMID:24659331

Vitale, Antonio; Rigante, Donato; Lopalco, Giuseppe; Brizi, Maria Giuseppina; Caso, Francesco; Franceschini, Rossella; Denaro, Rosario; Galeazzi, Mauro; Punzi, Leonardo; Iannone, Florenzo; Lapadula, Giovanni; Simpatico, Antonella; Marrani, Edoardo; Costa, Luisa; Cimaz, Rolando; Cantarini, Luca

2014-08-01

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An in vitro study on neuroprotective effects of serum containing Gengnianchun decoction and its main monomers against amyloid beta protein-induced cellular toxicity  

OpenAIRE

Obiective: To observe the effects of serum containing Gengnianchun (GNC) decoction, a compound traditional Chinese herbal medicine, and its monomers (paeoniflorin, berberine, timosaponin A-? and icariin) on neurotoxicity in PC12 cells induced by amyloid beta-protein (A?).?Methods: Injury of PC12 cells was induced by in incubating with A?25-35 in vitro.? Ovariectomized rats were intragastrically administered with GNC decoction twice daily for 5 days and then sera were obtained. Differe...

Wang, Wen-jun

2010-01-01

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Diagnostic radionuclide imaging of amyloid: biological targeting by circulating human serum amyloid P component  

International Nuclear Information System (INIS)

The specific molecular affinity of the normal plasma protein, serum amyloid P component (SAP), for all known types of amyloid fibrils was used to develop a new general diagnostic method for in-vivo radionuclide imaging of amyloid deposits. After intravenous injection of 123I-labelled purified human SAP there was specific uptake into amyloid deposits in all affected patients, 7 with systematic AL amyloid, 5 with AA amyloid, and 2 with ?2M amyloid, in contrast to the complete absence of any tissue localisation in 5 control subjects. Distinctive high-resolution scintigraphic images, even of minor deposits in the carpal regions, bone marrow, or adrenals, were obtained. This procedure should yield much information on the natural history and the management of amyloidosis, the presence of which has hitherto been confirmed only by biopsy. Clearance and metabolic studies indicated that, in the presence of extensive amyloidosis, the rate of synthesis of SAP was greatly increased despite maintenance of normal plasma levels. Futhermore, once localised to amyloid deposits the 123I-SAP persisted for long periods and was apparently protected from its normal rapid degradation. These findings shed new light on the pathophysiology of amyloid and may have implications for therapeutic strategies based upon specific molecular targeting with SAP. (author)

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Analysis of the functional roles of mammary serum amyloid A3 protein  

OpenAIRE

La Serum Amiloide A3 (M?S133) mamària és una proteïna de fase aguda expressada principalment a la glàndula mamària. Els nivells d'expressió de la M?S133 varia en diferents situacions fisiològiques, el que suggereix un rol important a nivell funcional. Per tal d'analitzar les propietats de la proteïna, es van dur a terme quatre estudis. En el primer, la M?S133 va ser expressada de forma recombinant en un sistema bacterià. Aquest pas és important ja que ens proporciona una font ...

Dome?nech Guitart, Anna

2013-01-01

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Serum amyloid P inhibits dermal wound healing  

Science.gov (United States)

The repair of open wounds depends on granulation tissue formation and contraction, which is primarily mediated by myofibroblasts. A subset of myofibroblasts originates from bone-marrow-derived monocytes which differentiate into fibroblast-like cells called fibrocytes. Serum amyloid P (SAP) inhibits ...

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The amyloid precursor protein: beyond amyloid  

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Full Text Available Abstract The amyloid precursor protein (APP takes a central position in Alzheimer's disease (AD pathogenesis: APP processing generates the ?-amyloid (A? peptides, which are deposited as the amyloid plaques in brains of AD individuals; Point mutations and duplications of APP are causal for a subset of early onset of familial Alzheimer's disease (FAD. Not surprisingly, the production and pathogenic effect of A? has been the central focus in AD field. Nevertheless, the biological properties of APP have also been the subject of intense investigation since its identification nearly 20 years ago as it demonstrates a number of interesting putative physiological roles. Several attractive models of APP function have been put forward recently based on in vitro biochemical studies. Genetic analyses of gain- and loss-of-function mutants in Drosophila and mouse have also revealed important insights into its biological activities in vivo. This article will review the current understanding of APP physiological functions.

Zheng Hui

2006-07-01

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Effects of Chinese herbal medicine Guanxinkang on lipid metabolism and serum C-reactive protein, amyloid A protein, and fibrinogen in apolipoprotein E-knockout mice with atherosclerosis  

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Full Text Available Objective: To observe the effects of Guanxinkang (GXK decoction, a compound traditional Chinese herbal medicine, on serum lipids and apolipoprotein A ? (ApoA ?, apolipoprotein B (ApoB, apolipoprotein E (ApoE, C-reactive protein (CRP, serum amyloid A protein (SAA and fibrinogen (Fbg concentrations of ApoE-knockout mice with atherosclerosis, and to explore the mechanism of GXK decoction in anti-atherosclerosis.Methods: Seventy 6-week-old ApoE-knockout mice receiving a high-cholesterol diet were used to induce atherosclerosis and were randomly divided into 5 groups: untreated group, simvastatin group and low- (drug concentration is 0.864 g/mL, medium- (1.728 g/mL, and high-dose (3.456 g/mL GXK groups. Another fourteen 6-week-old C57BL/6J mice were used as the normal control. Two 12-week-old mice were randomly selected from the normal control and the ApoE-knockout mice respectively to observe vulnerable plaque in the mouse’s aortic by hematoxylin-eosin staining. Blood was collected from venous plexus of eye socket after gavage of corresponding drugs once daily for 8 weeks continuously, and then the serum was separated. Triglyceride (TAG and total cholesterol (TC were measured by enzyme-coupled assay; low-density lipoprotein cholesterol (LDL-C and high-density lipoprotein cholesterol (HDL-C were measured by selective precipitation method. Serum levels of ApoA ? and ApoB were determined by turbidimetry. Double-antibody sandwich enzyme-linked immunosorbent assay was used to detect ApoE, CRP, SAA and Fbg concentrations in serum.Results: Compared with the normal control group, the levels of serum TC, TAG, LDL-C, ApoB, CRP, SAA and Fbg in the untreated group were increased (P<0.05, and the serum concentrations of HDL-C, ApoA ? and ApoE in the untreated group were decreased (P<0.05. After treatment, GXK decoction and simvastatin improved the dyslipidemia by increasing the concentrations of ApoA ? and HDL-C and decreasing the concentrations of TC, TAG, LDL-C, ApoB, CRP, SAA and Fbg (P<0.05. The high-dose GXK decoction had the most marked effects on SAA and Fbg and the serum lipids compared with the low-dose and medium-dose GXK and simvastatin.Conclusion: GXK decoction may not only provide an active effect on hyperlipidemia, but also down-regulate the levels of serum CRP, SAA and Fbg. GXK decoction exerts an anti-atherosclerosis effect in ApoE-knockout mice.

Mei-jiao Mao

2011-03-01

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Binding of complement proteins C1q and C4bp to serum amyloid P component (SAP) in solid contra liquid phase.  

DEFF Research Database (Denmark)

Serum amyloid P component (SAP), a member of the conserved pentraxin family of plasma proteins, binds calcium dependently to its ligands. The authors investigated SAPs interaction with the complement proteins C4b binding protein (C4bp) and C1q by ELISA, immunoelectrophoresis and electron microscopy. Binding of these proteins to SAP was demonstrated when SAP was immobilized using F(ab')2 anti-SAP, but not when SAP reacted with these proteins in liquid phase; thus the binding to human SAP was markedly phase state dependent. Presaturation of solid phase SAP with heparin, which binds SAP with high affinity, did not interfere with the subsequent binding of C4bp or C1q to SAP. In contrast, collagen I and IV showed partial competition with the binding of C1q to SAP. Using fresh serum, immobilized native SAP bound C4bp whereas binding of C1q/C1 could not be demonstrated. Altogether the results indicate that firm binding of C1q and C4bp to SAP requires that SAP is presented on a solid phase, that C1q and C4bp react with sites distinct from the heparin binding site, and that C1q and collagen I share binding sites on SAP. Immobilized native SAP, aggregated SAP and SAP-heparansulphate complexes induced no detectable complement activation.

SØrensen, Inge Juul; Nielsen, EH

1996-01-01

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Serum amyloid P component scintigraphy in familial amyloid polyneuropathy: regression of visceral amyloid following liver transplantation  

International Nuclear Information System (INIS)

Familial amyloid polyneuropathy (FAP) associated with transthyretin (TTR) mutations is the commonest type of hereditary amyloidosis. Plasma TTR is produced almost exclusively in the liver and orthotopic liver transplantation is the only available treatment, although the clinical outcome varies. Serum amyloid P component (SAP) scintigraphy is a method for identifying and quantitatively monitoring amyloid deposits in vivo, but it has not previously been used to study the outcome of visceral amyloid deposits in FAP following liver transplantation. Whole body scintigraphy following injection of iodine-123 labelled SAP was performed in 17 patients with FAP associated with TTR Met30 and in five asymptomatic gene carriers. Follow-up studies were performed in ten patients, eight of whom had undergone orthotopic liver transplantation 1-5 years beforehand. There was abnormal uptake of 123I-SAP in all FAP patients, including the kidneys in each case, the spleen in five cases and the adrenal glands in three cases. Renal amyloid deposits were also present in three of the asymptomatic carriers. Follow-up studies 1-5 years after liver transplantation showed that there had been substantial regression of the visceral amyloid deposits in two patients and modest improvement in three cases. The amyloid deposits were unchanged in two patients. In conclusion, 123I-SAP scintigraphy identified unsuspected visceral amyloid in each patient with FAP due to TTR Met30. The uh patient with FAP due to TTR Met30. The universal presence of renal amyloid probably underlies the high frequency of renal failure that occurs in FAP following liver transplantation. The variable capacity of patients to mobilise amyloid deposits following liver transplantation may contribute to their long-term clinical outcome. (orig.)

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Crystallizations of human serum amyloid P component (SAP)  

Science.gov (United States)

Human serum amyloid P component (SAP) crystallizes readily by batch methods at its isoelectric pH of 5.5 in the presence of calcium ions and small quantities of PEG 6000. Gel filtration under similar conditions shows the protein to be pentameric while under more physiological conditions of pH and ionic strength it is known to exist as stable decamers. The protein exhibits a calcium dependent affinity for the ?-D-galactopyranoside pyruvate acetal moiety of agarose. The isolated sugar has been successfully employed as a crystallization additive to modify growth rate and crystal habit.

O'Hara, B. P.; Wood, S. P.; Oliva, G.; White, H. E.; Pepys, M. B.

1988-07-01

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Inflammation protein SAA2.2 spontaneously forms marginally stable amyloid fibrils at physiological temperature†  

OpenAIRE

For nearly four decades, the formation of amyloid fibrils by the inflammation-related protein serum amyloid A (SAA) has been pathologically linked to the disease amyloid A (AA) amyloidosis. However, here we show that the non-pathogenic murine SAA2.2 spontaneously forms marginally stable amyloid fibrils at 37 °C that exhibit cross-beta structure, binding to thioflavin T, and fibrillation by a nucleation-dependent seeding mechanism. In contrast to the high stability of most known amyloid fibri...

Ye, Zhuqiu; Bayron, Diane; Aguilera, J. Javier; Srinivasan, Saipraveen; Wang, Yun; Serpell, Louise C.; Colo?n, Wilfredo

2011-01-01

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An in vitro study on neuroprotective effects of serum containing Gengnianchun decoction and its main monomers against amyloid beta protein-induced cellular toxicity  

Directory of Open Access Journals (Sweden)

Full Text Available Obiective: To observe the effects of serum containing Gengnianchun (GNC decoction, a compound traditional Chinese herbal medicine, and its monomers (paeoniflorin, berberine, timosaponin A-? and icariin on neurotoxicity in PC12 cells induced by amyloid beta-protein (A?.?Methods: Injury of PC12 cells was induced by in incubating with A?25-35 in vitro.? Ovariectomized rats were intragastrically administered with GNC decoction twice daily for 5 days and then sera were obtained. Different concentrations of serum containing GNC decoction and its main monomers including paeoniflorin, berberine, timosaponin and icariine and the monomer mixtures were cultured with PC12 cells to determine the best concentration of the drugs by methyl thiazolyl tetrazolium (MTT method. The effective concentration of A?25-35 was detemined by culturing PC12 cells with different concentrations of A?25-35. Then, the activity of PC12 cells with A?25-35-induced injury was observed with MTT method. Cellular morphological change was observed by phase contrast microscopy. Flow cytometry and fluorescence microscopy were employed to observe the A?25-35-induced early apoptosis of PC12 cells.?Results: After A?25-35 induction, the PC12 cells were fewer in number, less viable with shrinked cel1 body, many fragments, adhered less and nuclei shrinked. The cell proliferation was inhibited by A?25-35 concentration- and time?dependently. A?25-35 at concentration of 20 ?mol/ L was selected to construct the Alzheimer's disease model ?in vitro.? The sera containing GNC decoction could reinforce PC12 cell activity, and concentration at 20% was better than other concentrations after 24-, 48- and 72-hour culture. The 20% serum containing GNC decoction, 0.1 ?mol/L berberin and monomer mixture 3 including 1 mg/mL paeoniflorin, 1 ?mol/L berberine, 1 ?mol/L timosaponin and 1 ng/mL icariine could antagonize neurotoxicity induced by A?25-35. Moreover, they could inhibit A?25-35-induced early apoptosis of PC12 cells, with the effect of 20% serum containing GNC decoction better than 0.1 ?mol/L berberine and monomer mixture 3.Conclusion: Serum containing GNC decoction at 20% concentration has the potential neuroprotective effect on A?-induced cellular impairment. The serum containing GNC decoction was found to be stronger in action than the main monomers.

Wen-jun WANG

2010-01-01

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Serum Amyloid A Truncations in Type 2 Diabetes Mellitus  

Science.gov (United States)

Serum Amyloid A (SAA) is an acute phase protein complex consisting of several abundant isoforms. The N- terminus of SAA is critical to its function in amyloid formation. SAA is frequently truncated, either missing an arginine or an arginine-serine dipeptide, resulting in isoforms that may influence the capacity to form amyloid. However, the relative abundance of truncated SAA in diabetes and chronic kidney disease is not known. Methods Using mass spectrometric immunoassay, the abundance of SAA truncations relative to the native variants was examined in plasma of 91 participants with type 2 diabetes and chronic kidney disease and 69 participants without diabetes. Results The ratio of SAA 1.1 (missing N-terminal arginine) to native SAA 1.1 was lower in diabetics compared to non-diabetics (p = 0.004), and in males compared to females (p<0.001). This ratio was negatively correlated with glycated hemoglobin (r = ?0.32, p<0.001) and triglyceride concentrations (r = ?0.37, p<0.001), and positively correlated with HDL cholesterol concentrations (r = 0.32, p<0.001). Conclusion The relative abundance of the N-terminal arginine truncation of SAA1.1 is significantly decreased in diabetes and negatively correlates with measures of glycemic and lipid control. PMID:25607823

Yassine, Hussein N.; Trenchevska, Olgica; He, Huijuan; Borges, Chad R.; Nedelkov, Dobrin; Mack, Wendy; Kono, Naoko; Koska, Juraj; Reaven, Peter D.; Nelson, Randall W.

2015-01-01

24

Protein electrophoresis - serum  

Science.gov (United States)

This lab test measures the types of protein in the fluid (serum) part of a blood sample. Other electrophoresis tests that measure proteins in the serum include: Immunoelectrophoresis Immunofixation Globulin electrophoresis

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Amyloid Aggregation and Membrane Disruption by Amyloid Proteins  

Science.gov (United States)

Amyloidogenesis has been the focus of intense basic and clinical research, as an increasing number of amyloidogenic proteins have been linked to common and incurable degenerative diseases including Alzheimer's, type II diabetes, and Parkinson's. Recent studies suggest that the cell toxicity is mainly due to intermediates generated during the assembly process of amyloid fibers, which have been proposed to attack cells in a variety of ways. Disruption of cell membranes is believed to be one of the key components of amyloid toxicity. However, the mechanism by which this occurs is not fully understood. Our research in this area is focused on the investigation of the early events in the aggregation and membrane disruption of amyloid proteins, Islet amyloid polypeptide protein (IAPP, also known as amylin) and amyloid-beta peptide, on the molecular level. Structural insights into the mechanisms of membrane disruption by these amyloid proteins and the role of membrane components on the membrane disruption will be presented.[4pt] References:[0pt] [1] Sciacca et al., Biophys. J. 2012, 103, 702-10.[0pt] [2] Sciacca et al., Biochemistry. 2012, 51, 7676-84[0pt] [3] Brender et al., Acc. Chem. Res. 2012, 45, 454-62.[0pt] [4] Nanga et al., Biochim. Biophys. Acta 2011, 1808, 2337-42.[0pt] [5] Brender et al., Biophys J. 2011, 100, 685-92.

Ramamoorthy, Ayyalusamy

2013-03-01

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A pertussis toxin sensitive G-protein-independent pathway is involved in serum amyloid A-induced formyl peptide receptor 2-mediated CCL2 production  

OpenAIRE

Serum amyloid A (SAA) induced CCL2 production via a pertussis toxin (PTX)-insensitive pathway in human umbilical vein endothelial cells (HUVECs). SAA induced the activation of three MAPKs (ERK, p38 MAPK, and JNK), which were completely inhibited by knock-down of formyl peptide receptor 2 (FPR2). Inhibition of p38 MAPK and JNK by their specific inhibitors (SB203580 and SP600125), or inhibition by a dominant negative mutant of p38 MAPK dramatically decreased SAA-induced CCL2 production. Inactiv...

Lee, Ha Young; Kim, Sang Doo; Shim, Jae Woong; Kim, Hak Jung; Yun, Jeanho; Baek, Suk-hwan; Kim, Koanhoi; Bae, Yoe-sik

2010-01-01

27

Transthyretin sequesters amyloid beta protein and prevents amyloid formation.  

OpenAIRE

The cardinal pathological features of Alzheimer disease are depositions of aggregated amyloid beta protein (A beta) in the brain and cerebrovasculature. However, the A beta is found in a soluble form in cerebrospinal fluid in healthy individuals and patients with Alzheimer disease. We postulate that sequestration of A beta precludes amyloid formation. Failure to sequester A beta in Alzheimer disease may result in amyloidosis. When we added A beta to cerebrospinal fluid of patients and control...

Schwarzman, A. L.; Gregori, L.; Vitek, M. P.; Lyubski, S.; Strittmatter, W. J.; Enghilde, J. J.; Bhasin, R.; Silverman, J.; Weisgraber, K. H.; Coyle, P. K.

1994-01-01

28

Does serum degrade amyloid fibrils? Failure to confirm enzymatic degradation of amyloid A fibrils as the basis of the so-called ''amyloid degrading activity'' of serum  

International Nuclear Information System (INIS)

Several reports from different laboratories on the capacity of serum to degrade amyloid A fibrils have been published since the 1979 Symposium on Amyloidosis. These are based on the observation that whole serum or isolated serum albumin causes increased translucency in turbid agarose gels containing AA fibrils. We report here a critical study of the phenomenon itself both in the gel and in solution. The clearing capacity of serum samples correlated well with albumin concentration and as previously shown by others was manifested by isolated albumin preparations. Clearing did not involve enzymatic degradation of amyloid fibrils. Serum albumin is known to improve the optical clarity of agarose gels. We propose that optical clearing without degradation is the basis of the so-called amyloid degrading activity of human serum. This activity does not seem to be of in vivo importance in amyloidogenesis

29

Transthyretin sequesters amyloid beta protein and prevents amyloid formation  

DEFF Research Database (Denmark)

The cardinal pathological features of Alzheimer disease are depositions of aggregated amyloid beta protein (A beta) in the brain and cerebrovasculature. However, the A beta is found in a soluble form in cerebrospinal fluid in healthy individuals and patients with Alzheimer disease. We postulate that sequestration of A beta precludes amyloid formation. Failure to sequester A beta in Alzheimer disease may result in amyloidosis. When we added A beta to cerebrospinal fluid of patients and controls it was rapidly sequestered into stable complexes with transthyretin. Complexes with apolipoprotein E, which has been shown to bind A beta in vitro, were not observed in cerebrospinal fluid. Additional in vitro studies showed that both purified transthyretin and apolipoprotein E prevent amyloid formation.

Schwarzman, A L; Gregori, L

1994-01-01

30

Ligand-binding sites in human serum amyloid P component  

DEFF Research Database (Denmark)

Amyloid P component (AP) is a naturally occurring glycoprotein that is found in serum and basement membranes, AP is also a component of all types of amyloid, including that found in individuals who suffer from Alzheimer's disease and Down's syndrome. Because AP has been found to bind strongly and specifically to certain glycosaminoglycans that are components of amyloid deposits, AP may play an important role in the maintenance of amyloid. In the present work, we isolated and identified two proteolytic fragments of AP that are responsible for its heparin-binding activity. Neither fragment corresponds to published heparin-binding sequences. The structural requirements for activity of the peptides (amino acid residues 27-38 and 192-203 of AP) were examined by means of solid-phase inhibition assays with synthetic peptides, AP-(192-203)-peptide inhibits the Ca2+-dependent binding of AP to heparin with an IC50 of 25 mu M, while the IC50 of AP-(27-38)-peptide and AP-(33-38)-peptide are 10 mu M and 2 mu M, respectively, The understanding of the structure and function of active AP peptides will be useful for development of amyloid-targeted diagnostics and therapeutics.

Heegaard, N.H.H.; Heegaard, Peter M. H.

1996-01-01

31

Fibronectin and C4-binding protein are selectively bound by aggregated amyloid P component  

OpenAIRE

Serum amyloid P component (SAP) is a normal plasma protein, closely related to C-reactive protein, which is deposited together with amyloid fibrils in all forms of amyloidosis. It is also a normal constituent of human tissues, where it is found in vascular basement membranes and in association with the peripheral microfibrillar mantle of elastic fibres throughout the body. Very similar, highly conserved, homologous proteins are present in the sera of all vertebrates in which they have been so...

Debeer, Fc; Baltz, Ml; Holford, S.; Feinstein, A.; Pepys, Mb

1981-01-01

32

Haptoglobin and serum amyloid A in milk from dairy cows with chronic sub-clinical mastitis  

OpenAIRE

New tools are needed to detect chronic sub-clinical mastitis, especially in automatic milking systems. Haptoglobin and serum amyloid A (SAA) are the two most sensitive bovine acute phase proteins, and their concentrations increase in milk from cows with clinical mastitis and in milk from cows with experimentally induced chronic sub-clinical Staphylococcus aureus mastitis. The aim of this study was to further evaluate the potential for haptoglobin and SAA in milk as indicators of chronic sub-c...

Gro?nlund, Ulrika; Sandgren, Charlotte; Waller, Karin

2005-01-01

33

Biofilm Inhibitors that Target Amyloid Proteins  

OpenAIRE

Bacteria establish stable communities, known as biofilms, that are resistant to antimicrobials. Biofilm robustness is due to the presence of an extracellular matrix, which for several species - among them Bacillus subtilis - includes amyloid-like protein fibers. In this work, we show that B. subtilis biofilms can be a simple and reliable tool for screening of molecules with anti-amyloid activity. We identified two molecules, AA-861 and parthenolide, which efficiently inhibited biofilms by pre...

Romero, Diego; Sanabria-valenti?n, Edgardo; Vlamakis, Hera; Kolter, Roberto

2013-01-01

34

Expression of serum amyloid a in equine wounds  

DEFF Research Database (Denmark)

OBJECTIVES Aberrant wound healing with formation of exuberant granulation tissue (EGT) occurs frequently in horses and may affect their athletic career and quality of life. The objective of the study was to determine mRNA expression levels of serum amyloid A (SAA) in normal and aberrant wound healing in horses. METHODS Experimental wounds were made in six horses on both metatarsi and on regio brachii. One limb was bandaged to provoke formation of EGT. Biopsies were collected on day 21 and were divided in three groups: body wounds (regio brachii), unbandaged limb wounds (normal healing), and bandaged limb wounds (aberrant healing with formation of EGT). All biopsies were examined for the relative mRNA expression level of SAA using qRT-PCR. Differences in SAA expression levels between the three groups were analyzed by Kruskal-Wallis test and Dunns test. RESULTS SAA mRNA level was significantly higher (P < 0.01) in limb wounds healing with EGT formation than in body and limb wounds with normal healing. In body wounds and limb wounds with normal healing SAA expression was very low, in EGT SAA expression levels varied from low to very high. CONCLUSIONS SAA is a major equine acute phase protein, which is produced in the liver and several extrahepatic tissues during inflammatory conditions. This study shows that cells in EGT derived from horses produce SAA. This may be related to the length of the inflammatory phase of the wound healing, which is short (approximately 3 days) in wounds with normal healing, but protracted in wounds developing EGT. Chronic inflammation might facilitate binding of SAA-containing high density lipoproteins (HDL) to extracellular vascular proteoglycans, which would favour retention and modification of HDL by the vascular matrix. Such changes could be the pathophysiological reason underlying endothelial cell dysfunction and subsequently hypoxia, which has been implicated in EGT formation.

SØrensen, Mette Aamand; Jacobsen, Stine

35

The amyloid state of proteins in human diseases  

OpenAIRE

Amyloid fibers and oligomers are associated with a great variety of human diseases including Alzheimer’s disease and the prion conditions. Here we attempt to connect recent discoveries on the molecular properties of proteins in the amyloid state with observations about pathological tissues and disease states. We summarize studies of structure and nucleation of amyloid and relate these to observations on amyloid polymorphism, prion strains, co-aggregation of pathogenic proteins in tissues, a...

Eisenberg, David; Jucker, Mathias

2012-01-01

36

Imaging of experimental amyloidosis with 131I-labeled serum amyloid P component  

International Nuclear Information System (INIS)

131I-labeled human serum amyloid P component, which was injected into mice with experimentally induced systemic AA amyloidosis and into controls, became specifically localized and was retained in amyloidotic organs. In comparison, it was rapidly and completely eliminated from unaffected tissues and from control animals. Distinctive images of this amyloid-specific deposition of labeled serum amyloid P component were derived from whole body scanning, in vivo, of amyloidotic mice. These findings suggest that such imaging may have applications for the diagnosis and quantitation of amyloid deposits in humans

37

Serum concentrations of haptoglobin and serum amyloid A in water buffaloes (Bubalus bubalis) with abomasal ulcer.  

Science.gov (United States)

To evaluate the serum concentrations of haptoglobin (Hp) and serum amyloid A (SAA) in water buffaloes with abomasal ulcers, the abomasums of 100 randomly selected water buffaloes were examined after slaughter. Type I abomasal ulcers were found in 56 out of 100 buffaloes. Serum concentrations of Hp and SAA were measured. There was no significant difference between affected and non-affected buffaloes in the serum concentrations of Hp and SAA. The serum concentrations of Hp and SAA had no significant correlation with age and the serum SAA revealed no significant correlation with the number of abomasal ulcers. A significant correlation was found between the serum Hp and the number of abomasal ulcers (r =0.29, p = 0.04). There was no significant difference in the serum concentrations of Hp and SAA between buffaloes with different ulcer locations in the abomasums. Although more work on a larger number of animals is required in this area, it seems that the measurement of the serum Hp can be used to predict the abundance of type I abomasal ulcers. PMID:25610571

Tajik, Javad; Nazifi, Saeed; Heidari, Mahdi; Babazadeh, Marzieh

2012-01-01

38

Serum concentrations of haptoglobin and serum amyloid A in water buffaloes (Bubalus bubalis with abomasal ulcer  

Directory of Open Access Journals (Sweden)

Full Text Available To evaluate the serum concentrations of haptoglobin (Hp and serum amyloid A (SAA in water buffaloes with abomasal ulcers, the abomasums of 100 randomly selected water buffaloes were examined after slaughter. Type I abomasal ulcers were found in 56 out of 100 buffaloes. Serum concentrations of Hp and SAA were measured. There was no significant difference between affected and non-affected buffaloes in the serum concentrations of Hp and SAA. The serum concentrations of Hp and SAA had no significant correlation with age and the serum SAA revealed no significant correlation with the number of abomasal ulcers. A significant correlation was found between the serum Hp and the number of abomasal ulcers (r =0.29, p = 0.04. There was no significant difference in the serum concentrations of Hp and SAA between buffaloes with different ulcer locations in the abomasums. Although more work on a larger number of animals is required in this area, it seems that the measurement of the serum Hp can be used to predict the abundance of type I abomasal ulcers.

Javad Tajik

2012-09-01

39

Iodine-123-labelled serum amyloid P component scintigraphy in amyloidosis  

International Nuclear Information System (INIS)

This study describes the results of scintigraphy with iodine-123-labelled serum amyloid P component (SAP) as a means of establishing the distribution of organ involvement in amyloidosis. The significance of 123I-SAP scans obtained in 15 patients with biopsy-proven AA or AL amyloidosis is discussed. Biopsy-proven amyloidosis was typically confirmed by scintigraphy, though such confirmation was not obtained in the kidneys in six patients with histological proof of extensive renal amyloid deposition. This lack of uptake may have been due to the accumulation of a major part of the 123I-SAP in the spleen and/or liver. Twenty-four hour whole-body retention of 123I-SAP was higher in patients with amyloidosis than in controls. Twenty-four hour tracer accumulation of the radioactivity in the extravascular compartment was notably greater in patients than in controls and appeared to be a good diagnostic criterion. We conclude that 123I-SAP scintigraphy may be helpful for the evaluation of organ involvement not only in patients with biopsy-proven amyloidosis but also when a biopsy cannot be performed or when a strong suspicion of amyloidosis exists in spite of repeated negative biopsises. (orig.)

40

In Vitro Polymerization of a Functional Escherichia coli Amyloid Protein*  

OpenAIRE

Amyloid formation is characterized by the conversion of soluble proteins into biochemically and structurally distinct fibers. Although amyloid formation is traditionally associated with diseases such as Alzheimer disease, a number of biologically functional amyloids have recently been described. Curli are amyloid fibers produced by Escherichia coli that contribute to biofilm formation and other important physiological processes. We characterized the polymerization properties of the major curl...

Wang, Xuan; Smith, Daniel R.; Jones, Jonathan W.; Chapman, Matthew R.

2006-01-01

41

Cerebral Microvascular Amyloid ? Protein Deposition Induces Vascular Degeneration and Neuroinflammation in Transgenic Mice Expressing Human Vasculotropic Mutant Amyloid ? Precursor Protein  

OpenAIRE

Cerebral vascular amyloid ?-protein (A?) deposition, also known as cerebral amyloid angiopathy, is a common pathological feature of Alzheimer’s disease. Additionally, several familial forms of cerebral amyloid angiopathy exist including the Dutch (E22Q) and Iowa (D23N) mutations of A?. Increasing evidence has associated cerebral microvascular amyloid deposition with neuroinflammation and dementia in these disorders. We recently established a transgenic mouse model (Tg-SwDI) that expresse...

Miao, Jianting; Xu, Feng; Davis, Judianne; Otte-ho?ller, Irene; Verbeek, Marcel M.; Nostrand, William E.

2005-01-01

42

Role of serum amyloid P component in immune clearance  

International Nuclear Information System (INIS)

In order to clarify the mechanism of interaction of serum amyloid P component (SAP) with complement, the interaction of SAP with Clq was studied. It is known that SAP binds Sepharose 4B in the presence of calcium. 125I-Clq was retained on the Sepharose when purified 125I-Clq was incubated with SAP prior to affinity chromatography on Sepharose. In the absence of SAP, the 125I-Clq was not retained. To further examine the interaction of SAP with Clq, SAP was incubated at varying ratios with Clq. These mixtures were examined via crossed immunoelectro-immunoelectrophoresis against goat anti-SAP. A change in the electrophoretic behavior of SAP was observed in the presence of Clq. It was found that SAP interacted with the collagen-like stem of Clq. In these studies, 125I-SAP was incubated with pepsin digests of Clq in a microtitre solid-phase binding assay. In addition, a microtitre solid-phase binding assay was utilized in order to investigate the possible binding of SAP with IgG. The ability of SAP activate complement as detected by C3 conversion was studied. It was found that SAP activated complement to a limited extent in normal human serum but caused extensive C3 conversion when serum from an individual with decreased levels of Cl inhibitor was used. Furthermore, the action of the complement pathway by SAP in the latter serum was reversed by the addition of exogenous Cl inhibitor, indicating that SAP has the ability to play a cating that SAP has the ability to play a role in the regulation of complement via the classical pathway

43

Isoforms of murine and human serum amyloid P component  

DEFF Research Database (Denmark)

Isoelectric focusing (IEF) and immunofixation of murine serum amyloid P component (SAP), purified and in serum, showed a distinct and strain-dependent isoform pattern with up to seven bands (pI 5.1-5.7). Neuraminidase treatment caused a shift of the isoforms to more basic pI values, but did not affect their number. When the acute-phase response was analysed in three mouse strains, CBA/J and C3H/HeN initially showed seven SAP isoforms in serum and C57BL/6 J three or four. The responses in all three strains peaked at day 2 and were normalized within 14 days. On days 2 and 4, CBA/J and C3H/HeN mice showed one more acidic isoform and an increase in the concentration of the most basic isoform. C57BL/6 J mice exhibited two to three new isoforms during the acute-phase response. This appears to be the first demonstration of the physiological existence of SAP isoforms. In contrast, demonstration of isoforms of human SAP required the presence of urea and higher SAP concentrations. TEF and immunofixation of SAP monomersshowed five to eight isoforms, ranging from pI 4.7-5.7. IEF of SAP in human serum resulted in a less distinct pattern and more acidic isoforms. As with murine SAP, neuraminidase treatment caused a shift of the isoforms, but no reduction in isoform number. Two-dimensional gel electrophoresis confirmed the existence of multiple isoforms of human SAP monomers.

Nybo, Mads; Hackler, R

1998-01-01

44

Phorbol esters affect multiple steps in beta-amyloid precursor protein trafficking and amyloid beta-protein production.  

OpenAIRE

BACKGROUND: Amyloid beta-protein (A beta), the major constituent of amyloid deposits found in Alzheimer's disease, is derived from the beta-amyloid precursor protein (beta PP). Constitutive proteolysis by alpha-secretase and secretion of soluble beta PP (beta PPs) are stimulated by protein kinase C (PKC) activation, whereas A beta production and release are inhibited. The cellular mechanism that underlies the PKC-mediated down-regulation of A beta generation is unclear. Because endocytic proc...

Koo, E. H.

1997-01-01

45

Is amyloid beta-protein glycated in Alzheimer's disease?  

Science.gov (United States)

Recent data suggest that protein glycation is involved in the process of amyloid formation in Alzheimer's disease (AD). To further investigate this issue, we analyzed the presence of advanced glycation end products (AGE) in soluble and insoluble forms of amyloid beta-protein (A beta) as well as in apolipoprotein E (apoE), a protein bound to amyloid deposits. Both proteins were extracted from cerebral cortex obtained from patients with AD and probed by immunoblotting with two antibodies specific for different AGE, already known to immunocytochemically label amyloid plaques. All the AGE antibodies failed to recognize either A beta or apoE, whereas they reacted with synthetic A beta glycated in vitro. These findings indicate that other proteins associated with amyloid deposits are candidates to be modified with AGE in Alzheimer's cerebral tissue. PMID:9141062

Tabaton, M; Perry, G; Smith, M; Vitek, M; Angelini, G; Dapino, D; Garibaldi, S; Zaccheo, D; Odetti, P

1997-03-01

46

Beta-amyloid precursor protein cleavage by a membrane-bound protease.  

OpenAIRE

The principal component of amyloid plaques in Alzheimer disease is beta-amyloid protein, an approximately 4-kDa peptide derived from amyloid precursor proteins. Previous studies have established that amyloid precursor proteins are secreted after proteolytic cleavage within the beta-amyloid peptide. The present investigation documents that, in cultured cells, amyloid precursor protein is cleaved on the plasma membrane by a membrane-bound endoprotease and that the specificity of peptide bond hy...

Sisodia, S. S.

1992-01-01

47

Statistical Mechanical Treatments of Protein Amyloid Formation  

CERN Document Server

Protein aggregation is an important field of investigation because it is closely related to the problem of neurodegenerative diseases, to the development of biomaterials, and to the growth of cellular structures such as cyto-skeleton. Self-aggregation of protein amyloids, for example, is a complicated process involving many species and levels of structures. This complexity, however, can be dealt with using statistical mechanical tools, such as free energies, partition functions, and transfer matrices. In this article, we review general strategies for studying protein aggregation using statistical mechanical approaches and show that canonical and grand canonical ensembles can be used in such approaches. The grand canonical approach is particularly convenient since competing pathways of assembly and dis-assembly can be considered simultaneously. Another advantage of using statistical mechanics is that numerically exact solutions can be obtained for all of the thermodynamic properties of fibrils, such as the amo...

Schreck, John S

2013-01-01

48

Exogenous amyloidogenic proteins function as seeds in amyloid ?-protein aggregation.  

Science.gov (United States)

Amyloid ?-protein (A?) aggregation is considered to be a critical step in the neurodegeneration of Alzheimer's disease (AD). In addition to A?, many proteins aggregate into the amyloid state, in which they form elongated fibers with spines comprising stranded ?-sheets. However, the cross-seeding effects of other protein aggregates on A? aggregation pathways are not completely clear. To investigate the cross-seeding effects of exogenous and human non-CNS amyloidogenic proteins on A? aggregation pathways, we examined whether and how sonicated fibrils of casein, fibroin, sericin, actin, and islet amyloid polypeptide affected A?40 and A?42 aggregation pathways using the thioflavin T assay and electron microscopy. Interestingly, the fibrillar seeds of all amyloidogenic proteins functioned as seeds. The cross-seeding effect of actin was stronger but that of fibroin was weaker than that of other proteins. Furthermore, our nuclear magnetic resonance spectroscopic studies identified the binding sites of A? with the amyloidogenic proteins. Our results indicate that the amyloidogenic proteins, including those contained in foods and cosmetics, contribute to A? aggregation by binding to A?, suggesting their possible roles in the propagation of A? amyloidosis. PMID:24440525

Ono, Kenjiro; Takahashi, Ryoichi; Ikeda, Tokuhei; Mizuguchi, Mineyuki; Hamaguchi, Tsuyoshi; Yamada, Masahito

2014-04-01

49

What is the role of amyloid precursor protein dimerization?  

OpenAIRE

Extensive research efforts have been conducted over the past decades to understand the processing of the Amyloid Precursor Protein (APP). APP cleavage leads to the production of the ?-amyloid peptide (A?), which is the major constituent of the amyloid core of senile plaques found in the brains of patients with Alzheimer disease (AD). A? is produced by the sequential cleavage of APP by ?- and ?-secretases. Cleavage of APP by ?-secretase also generates the APP Intracellular C-terminal Dom...

Ben Khalifa, Naouel; Hees, Joanne; Tasiaux, Bernadette; Huysseune, Sandra; Smith, Steven O.; Constantinescu, Stefan N.; Octave, Jean-noe?l; Kienlen-campard, Pascal

2010-01-01

50

Effect of Anticoagulants on Amyloid ?-Protein Precursor and Amyloid Beta Levels in Plasma  

OpenAIRE

Altered levels of amyloid ?-protein precursor (A?PP) and/or amyloid beta (A?) are characteristic of several neurological disorders including Alzheimer's disease (AD), Down syndrome (DS), Fragile X syndrome (FXS), Parkinson's disease (PD), autism and epilepsy. Thus, these proteins could serve as valuable blood-based biomarkers for assessing disease severity and pharmacological efficacy. We have observed significant differences in A?1–42 levels in human plasma dependent on the anticoagula...

Westmark, Cara J.; Hervey, Crystal M.; Berry-kravis, Elizabeth M.; Malter, James S.

2011-01-01

51

Polarized secretion of beta-amyloid precursor protein and amyloid beta-peptide in MDCK cells.  

OpenAIRE

The beta-amyloid precursor protein (beta APP) is a widely expressed integral membrane protein that is proteolytically processed to yield several secreted derivatives, including soluble APP (APPs), the 4-kDa amyloid beta-peptide (A beta), and a related 3-kDa peptide (p3). To understand beta APP trafficking and processing, we analyzed the sorting of beta APP in Madin-Darby canine kidney (MDCK) cells, an epithelial cell known to possess physiologically distinct apical and basol...

Haass, C.; Koo, E. H.; Teplow, D. B.; Selkoe, D. J.

1994-01-01

52

Reference intervals for acute phase protein and serum protein electrophoresis values in captive Asian elephants (Elephas maximus).  

Science.gov (United States)

Acute phase protein (APP) immunoassays and serum protein electrophoresis (SPEP) are assays for evaluating the inflammatory response and have use as diagnostic tools in a variety of species. Acute phase proteins are markers of inflammation that are highly conserved across different species while SPEP separates and quantifies serum protein fractions based on their physical properties. In the current study, serum samples from 35 clinically healthy Asian elephants (Elephas maximus) were analyzed using automated assays for C-reactive protein, serum amyloid A, and haptoglobin and SPEP. Robust methods were used to generate reference intervals for the APPs: C-reactive protein (1.3-12.8 mg/l), serum amyloid A (0-47.5 mg/l), and haptoglobin (0-1.10 mg/ml). In addition, SPEP was performed on these samples to establish reference intervals for each protein fraction. A combination of APPs and SPEP measurements are valuable adjunctive diagnostic tools in elephant health care. PMID:25057161

Isaza, Ramiro; Wiedner, Ellen; Hiser, Sarah; Cray, Carolyn

2014-09-01

53

Formation of soluble amyloid oligomers and amyloid fibrils by the multifunctional protein vitronectin  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The multifunctional protein vitronectin is present within the deposits associated with Alzheimer disease (AD, age-related macular degeneration (AMD, atherosclerosis, systemic amyloidoses, and glomerulonephritis. The extent to which vitronectin contributes to amyloid formation within these plaques, which contain misfolded, amyloidogenic proteins, and the role of vitronectin in the pathophysiology of the aforementioned diseases is currently unknown. The investigation of vitronectin aggregation is significant since the formation of oligomeric and fibrillar structures are common features of amyloid proteins. Results We observed vitronectin immunoreactivity in senile plaques of AD brain, which exhibited overlap with the amyloid fibril-specific OC antibody, suggesting that vitronectin is deposited at sites of amyloid formation. Of particular interest is the growing body of evidence indicating that soluble nonfibrillar oligomers may be responsible for the development and progression of amyloid diseases. In this study we demonstrate that both plasma-purified and recombinant human vitronectin readily form spherical oligomers and typical amyloid fibrils. Vitronectin oligomers are toxic to cultured neuroblastoma and retinal pigment epithelium (RPE cells, possibly via a membrane-dependent mechanism, as they cause leakage of synthetic vesicles. Oligomer toxicity was attenuated in RPE cells by the anti-oligomer A11 antibody. Vitronectin fibrils contain a C-terminal protease-resistant fragment, which may approximate the core region of residues essential to amyloid formation. Conclusion These data reveal the propensity of vitronectin to behave as an amyloid protein and put forth the possibilities that accumulation of misfolded vitronectin may contribute to aggregate formation seen in age-related amyloid diseases.

Langen Ralf

2008-10-01

54

Time-course monitoring of serum amyloid A in a cat with pancreatitis.  

Science.gov (United States)

Time-course changes in the concentration of serum amyloid A (SAA), a major acute phase protein, were measured in a cat with pancreatitis over an 831-day period and compared with changes in WBC count and feline trypsin-like immunoreactivity (fTLI). SAA concentration was increased at the onset of the disease and gradually decreased over 5 days of treatment with an improvement in the clinical condition. In contrast, fTLI concentration and WBC count were not increased at the onset of the disease but increased gradually during the 5 days of treatment. Long-term monitoring from days 68 to 831 revealed a good correlation between SAA concentration and the reoccurrence of clinical signs in the cat; however, WBC count did not increase even with the exacerbation of disease. These findings suggest that the SAA concentration may be a useful marker for evaluating response to treatment and disease exacerbation in feline pancreatitis. PMID:19228363

Tamamoto, Takashi; Ohno, Koichi; Ohmi, Aki; Seki, Izumi; Tsujimoto, Hajime

2009-03-01

55

Serum amyloid A circulating levels and disease activity in patients with juvenile idiopathic arthritis.  

Science.gov (United States)

The aim of our study was to evaluate the association between circulating levels of serum amyloid A protein (SAA) and disease activity in patients with juvenile idiopathic arthritis (JIA). Our study group included 41 JIA patients (9 male, 32 female), classified according to the International League of Associations for Rheumatology (ILAR) criteria (5); 16 had polyarticular onset disease and 25 had oligoarticular onset disease. Among 25 patients with oligoarticular disease, three had extended oligoarthritis. Serum amyloid A (SAA), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were measured in both patients and 26 healthy controls. SAA levels were higher in JIA patients versus healthy controls (p<0.001). Significant positive correlations were found between SAA and the presence of active joints (rho=0.363, p<0.05), the number of active joints (rho=0.418, p<0.05), ESR (R=0.702, p<0.05) and CRP (R=0.827, p<0.05). No significant correlations between ESR and the presence of active joints (rho=0.221, p=0.225) or between ESR and the number of active joints (rho=0.118, p=0.520) were demonstrated in JIA patients. No significant correlations were obtained between CRP and the presence of active joints (rho=0.034, p=0.855) or between CRP and the number of active joints (rho=0.033, p=0.859). We discovered a significant increase in SAA levels in JIA patients, compared to controls, and a strong positive correlation between SAA level and JIA disease activity. We also discerned SAA to be a more sensitive laboratory marker than ESR and CRP for evaluating the presence and number of active joints. We suggest that SAA can be used as an additional indicator of disease activity in JIA. PMID:22869491

Cantarini, Luca; Giani, Teresa; Fioravanti, Antonella; Iacoponi, Francesca; Simonini, Gabriele; Pagnini, Ilaria; Spreafico, Adriano; Chellini, Federico; Galeazzi, Mauro; Cimaz, Rolando

2012-09-01

56

Amyloid precursor protein (APP) regulates synaptic structure and function  

OpenAIRE

The amyloid precursor protein (APP) plays a critical role in Alzheimer’s disease (AD) pathogenesis. APP is proteolytically cleaved by ?- and ?-secretases to generate the amyloid ?-protein (A?), the core protein component of senile plaques in AD. It is also cleaved by ?-secretase to release the large soluble APP (sAPP) luminal domain that has been shown to exhibit trophic properties. Increasing evidence points to the development of synaptic deficits and dendritic spine loss prior to dep...

Tyan, Sheue-houy; Shih, Ann Yu-jung; Walsh, Jessica J.; Murayama, Hiroko; Sarsoza, Floyd; Ku, Lawrence; Eggert, Simone; Hof, Patrick R.; Koo, Edward H.; Dickstein, Dara L.

2012-01-01

57

Serum amyloid a is a marker for pulmonary involvement in systemic sclerosis.  

Science.gov (United States)

Inflammation in systemic sclerosis (SSc) is a prominent, but incompletely characterized feature in early stages of the disease. The goal of these studies was to determine the circulating levels, clinical correlates and biological effects of the acute phase protein serum amyloid A (SAA), a marker of inflammation, in patients with SSc. Circulating levels of SAA were determined by multiplex assays in serum from 129 SSc patients and 98 healthy controls. Correlations between SAA levels and clinical and laboratory features of disease were analyzed. The effects of SAA on human pulmonary fibroblasts were studied ex vivo. Elevated levels of SAA were found in 25% of SSc patients, with the highest levels in those with early-stage disease and diffuse cutaneous involvement. Significant negative correlations of SAA were found with forced vital capacity and diffusion capacity for carbon monoxide. Patients with elevated SAA had greater dyspnea and more frequent interstitial lung disease, and had worse scores on patient-reported outcome measures. Incubation with recombinant SAA induced dose-dependent stimulation of IL-6 and IL-8 in normal lung fibroblasts in culture. Serum levels of the inflammatory marker SAA are elevated in patients with early diffuse cutaneous SSc, and correlate with pulmonary involvement. In lung fibroblasts, SAA acts as a direct stimulus for increased cytokine production. These findings suggest that systemic inflammation in SSc may be linked to lung involvement and SAA could serve as a potential biomarker for this complication. PMID:25629975

Lakota, Katja; Carns, Mary; Podlusky, Sofia; Mrak-Poljsak, Katjusa; Hinchcliff, Monique; Lee, Jungwha; Tomsic, Matija; Sodin-Semrl, Snezna; Varga, John

2015-01-01

58

Beta amyloid-independent role of amyloid precursor protein in generation and maintenance of dendritic spines  

OpenAIRE

Synapse loss induced by amyloid beta (A?) is thought to be a primary contributor to cognitive decline in Alzheimer’s disease. A? is generated by proteolysis of amyloid precursor protein (APP), a synaptic receptor whose physiological function remains unclear. In the present study, we investigated the role of APP in dendritic spine formation, which is known to be important for learning and memory. We found that overexpression of APP increased spine number, whereas knockdown of APP reduced s...

Lee, Kea Joo; Moussa, Charbel E. -h; Lee, Yeunkum; Sung, Youme; Howell, Brian W.; Turner, Raymond Scott; Pak, Daniel T. S.; Hoe, Hyang-sook

2010-01-01

59

Zinc Inhibits Amyloid ? Production from Alzheimer's Amyloid Precursor Protein in SH-SY5Y Cells  

OpenAIRE

Zinc released from excited glutamatergic neurons accelerates amyloid ? (A?) aggregation, underscoring the therapeutic potential of zinc chelation for the treatment of Alzheimer's disease (AD). Zinc can also alter A? concentration by affecting its degradation. In order to elucidate the possible role of zinc influx in secretase-processed A? production, SH-SY5Y cells stably expressing amyloid precursor protein (APP) were treated with pyrrolidine dithiocarbamate (PDTC), a zinc ionophore, and ...

Lee, Jinu; Kim, Chul Hoon; Kim, Dong Goo; Ahn, Young Soo

2009-01-01

60

AMPA Receptor Activation Promotes Non-Amyloidogenic Amyloid Precursor Protein Processing and Suppresses Neuronal Amyloid-? Production  

OpenAIRE

Soluble oligomeric amyloid ? peptide (A?) generated from processing of the amyloid precursor protein (APP) plays a central role in the pathogenesis of Alzheimer's Disease (AD) and through actions at glutamatergic synapses affects excitability and plasticity. The physiological control of APP processing is not fully understood but stimulation of synaptic NMDA receptors (NMDAR) can suppress A? levels through an ERK-dependent increase in ?-secretase activity. AMPA-type glutamate receptors (AM...

Hoey, Sarah E.; Buonocore, Federica; Cox, Carla J.; Hammond, Victoria J.; Perkinton, Michael S.; Williams, Robert J.

2013-01-01

61

Genetic Dissection of the Amyloid Precursor Protein in Developmental Function and Amyloid Pathogenesis*?  

OpenAIRE

Proteolytic processing of the amyloid precursor protein (APP) generates large soluble APP derivatives, ?-amyloid (A?) peptides, and APP intracellular domain. Expression of the extracellular sequences of APP or its Caenorhabditis elegans counterpart has been shown to be sufficient in partially rescuing the CNS phenotypes of the APP-deficient mice and the lethality of the apl-1 null C. elegans, respectively, leaving open the question as what is the role of the highly conserved APP intracellul...

Li, Hongmei; Wang, Zilai; Wang, Baiping; Guo, Qinxi; Dolios, Georgia; Tabuchi, Katsuhiko; Hammer, Robert E.; Su?dhof, Thomas C.; Wang, Rong; Zheng, Hui

2010-01-01

62

Serum Amyloid A as a Predictive Marker for Radiation Pneumonitis in Lung Cancer Patients  

Energy Technology Data Exchange (ETDEWEB)

Purpose: To investigate serum markers associated with radiation pneumonitis (RP) grade ?3 in patients with lung cancer who were treated with radiation therapy. Methods and Materials: Pretreatment serum samples from patients with stage Ib-IV lung cancer who developed RP within 1 year after radiation therapy were analyzed to identify a proteome marker able to stratify patients prone to develop severe RP by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS). Dosimetric parameters and 3 biological factors were compared. Results: Serum samples from 16 patients (28%) with severe RP (grade 3-4) and 42 patients (72%) with no or mild RP (grade 0-2) were collected for analysis. All patients received a median of 54 Gy (range, 42-70 Gy) of three-dimensional conformal radiation therapy with a mean lung dose (MLD) of 1502 cGy (range, 700-2794 cGy). An m/z peak of 11,480 Da was identified by SELDI-TOF-MS, and serum amyloid A (SAA) was the primary splitter serum marker. The receiver operating characteristic area under the curve of SAA (0.94; 95% confidence interval [CI], 0.87-1.00) was higher than those of C-reactive protein (0.83; 95% CI, 0.72-0.94), interleukin-6 (0.79; 95% CI, 0.65-0.94), and MLD (0.57; 95% CI, 0.37-0.77). The best sensitivity and specificity of combined SAA and MLD for predicting RP were 88.9% and 96.0%, respectively. Conclusions: Baseline SAA could be used as an auxiliary marker for predicting severe RP. Extreme care should be taken to limit the lung irradiation dose in patients with high SAA.

Wang, Yu-Shan [Department of Radiation Therapy and Oncology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan (China); Department of Animal Science, National Ilan University, Ilan, Taiwan (China); Chang, Heng-Jui [Department of Radiation Therapy and Oncology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan (China); Chang, Yue-Cune [Department of Mathematics, Tamkang University, Taipei, Taiwan (China); Huang, Su-Chen; Ko, Hui-Ling; Chang, Chih-Chia [Department of Radiation Therapy and Oncology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan (China); Yeh, Yu-Wung; Jiang, Jiunn-Song [Department of Chest Medicine, Shin-Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan (China); Lee, Cheng-Yen; Chi, Mau-Shin [Department of Radiation Therapy and Oncology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan (China); Chi, Kwan-Hwa, E-mail: M006565@ms.skh.org.tw [Department of Radiation Therapy and Oncology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan (China); Institute of Radiation Science and School of Medicine, National Yang-Ming University, Taipei, Taiwan (China)

2013-03-01

63

Serum Amyloid A as a Predictive Marker for Radiation Pneumonitis in Lung Cancer Patients  

International Nuclear Information System (INIS)

Purpose: To investigate serum markers associated with radiation pneumonitis (RP) grade ?3 in patients with lung cancer who were treated with radiation therapy. Methods and Materials: Pretreatment serum samples from patients with stage Ib-IV lung cancer who developed RP within 1 year after radiation therapy were analyzed to identify a proteome marker able to stratify patients prone to develop severe RP by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS). Dosimetric parameters and 3 biological factors were compared. Results: Serum samples from 16 patients (28%) with severe RP (grade 3-4) and 42 patients (72%) with no or mild RP (grade 0-2) were collected for analysis. All patients received a median of 54 Gy (range, 42-70 Gy) of three-dimensional conformal radiation therapy with a mean lung dose (MLD) of 1502 cGy (range, 700-2794 cGy). An m/z peak of 11,480 Da was identified by SELDI-TOF-MS, and serum amyloid A (SAA) was the primary splitter serum marker. The receiver operating characteristic area under the curve of SAA (0.94; 95% confidence interval [CI], 0.87-1.00) was higher than those of C-reactive protein (0.83; 95% CI, 0.72-0.94), interleukin-6 (0.79; 95% CI, 0.65-0.94), and MLD (0.57; 95% CI, 0.37-0.77). The best sensitivity and specificity of combined SAA and MLD for predicting RP were 88.9% and 96.0%, respectively. Conclusions: Baseline SAA could be used as an auxiliary marker for predicting severe RP. Extreme care should be taken to limit the lung irradiation dose in patients with high SAA

64

Formation of soluble amyloid oligomers and amyloid fibrils by the multifunctional protein vitronectin  

OpenAIRE

Abstract Background The multifunctional protein vitronectin is present within the deposits associated with Alzheimer disease (AD), age-related macular degeneration (AMD), atherosclerosis, systemic amyloidoses, and glomerulonephritis. The extent to which vitronectin contributes to amyloid formation within these plaques, which contain misfolded, amyloidogenic proteins, and the role of vitronectin in the pathophysiology of the aforementioned diseases is currently unknown. The investigation of vi...

Langen Ralf; Glabe Charles G; Kayed Rakez; Hsieh Chia-Ling; Mario, Isas J.; Shin Thuzar M; Chen Jeannie

2008-01-01

65

The physico-chemical, antigenic, and functional heterogeneity of human serum amyloid A  

International Nuclear Information System (INIS)

In the present study we attempted to develop a rapid method to isolate serum amyloid A isomers (SAA is.) and to determine whether this physicochemical heterogeneity corresponds to an antigenic and functional one. Pure human low molecular SAA (SAAL) was prepared from the serum of 6 patients (pts.) using standard techniques. Preparative isoelectric focusing in agarose/sephadex gels was used to separate SAAL is. Monoclonal antibodies (m. abs.) to SAAL and to AA were prepared by hybridization of P3XU-1 nonsecretory murine myeloma cells with murine spleen cells from Balb/c mice immunized with pooled SAAL and AA respectively. Four distinctly migrating SAAL isomers with PI's of 4.9, 5.8, 6.6, and 7.2 were isolated from 6 pts. while only three isomers were separated from the pt. with myasthenia gravis. Four m. abs. to SAAL, one to AA, six m. abs. to SAAL-2 is. and one to SAAL-1 is. were generated in murine ascitic fluid. Dishes coated with the four human SAA is., human AA, various mammalian and human proteins as well as with serum from 31 pts. with metastatic Ca. and 23 pts. with inflammatory diseases (ID) were reacted with the m. abs. The amount of binding was determined using 125I labelled goat antimouse serum. The m. abs. to SAA were found specific for human SAA recognizing two different patterns in relationship to the intensity of binding to SAA is. One of them (7A2-43) had a greater affinity for SAA from pts with ID, while the other (5A6-5) reacted stronger wihile the other (5A6-5) reacted stronger with SAA from pts with metastatic Ca

66

Serum amyloid A and haptoglobin concentrations in serum and peritoneal fluid of healthy horses and horses with acute abdominal pain  

DEFF Research Database (Denmark)

BACKGROUND: Peritoneal fluid (PF) analysis is a valuable diagnostic tool in equine medicine. Markers such as serum amyloid A (SAA) and haptoglobin (Hp) could facilitate the diagnosis of inflammatory abdominal conditions. OBJECTIVES: The objectives were to (1) establish reference intervals (RI) for SAA and Hp in serum and PF in healthy horses, (2) compare SAA and Hp concentrations between healthy horses and horses with colic, and (3) to assess the correlation between serum and PF concentrations. METHODS: Serum amyloid A and Hp concentrations were determined by automated assays in prospectively enrolled healthy reference horses and horses with colic. RIs were calculated, group concentrations were compared by Student's t-test, and Pearson's correlation for serum and PF concentrations were determined. RESULTS: In healthy horses (n = 62) the measurements for SAA were below the detection limit (0.5 mg/L) in 94% of serum samples and 98% of PF samples. Horses with colic (n = 61) had statistically significantly increased SAA concentrations in serum (P 

Pihl, Tina Holberg; Andersen, Pia Haubro

2013-01-01

67

Genetic polymorphisms of serum amyloid A1 and coronary artery disease risk.  

Science.gov (United States)

Serum amyloid A (SAA) protein is not only an inflammatory factor but also an apolipoprotein that can replace apolipoprotein A1 (apoA1) as the major apolipoprotein of high-density lipoprotein cholesterol (HDL-C). However, the relationship between genetic polymorphisms of SAA and coronary artery disease (CAD) remains unclear. A total of four single nucleotide polymorphisms (rs12218, rs4638289, rs7131332, and rs11603089) of the SAA gene were genotyped using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method in two independent case-control studies, one of the Han population (1416 CAD patients and 1373 control subjects) and the other of the Uygur population (588 CAD patients and 529 control subjects). We found that the rs12218 CC genotype was more frequent among the CAD patients than among the controls in both the Han (8.3% vs. 4.8%, P?diabetes, and serum levels of triglycerides, total cholesterol, HDL, and plasma SAA, the differences remained significant in the Han (CC vs. CT+TT, P?

Xie, X; Ma, Y-T; Yang, Y-N; Li, X-M; Zheng, Y-Y; Liu, F; Ma, X; Fu, Z-Y; Yu, Z-X; Chen, Y; Chen, B-D; Huang, Y

2015-03-01

68

Haptoglobin and serum amyloid a in subacute ruminal acidosis in goats  

Directory of Open Access Journals (Sweden)

Full Text Available Ruminal acidosis is a frequent disorder that occurs in goats as a consequence of feedingmistakes in animals not adapted to a diet of easily fermentable carbohydrates. The subacuteform of the disease is difficult to diagnose because no apparent signs are shownand the acid-base parameters may remain within the normal range. The present studyaimed at testing the hypothesis that haptoglobin (Hp and serum amyloid A (SAA,the two major acute phase proteins in ruminants, may be useful as markers of subacuteacidosis in goats.A subacute acidosis was induced in six Murciano-Granadina goats through a diet of60% mixed feed-40% alfalfa hay offered during 5 days to goats not adapted to eatmixed feed. Two goats were rumen-fistulated to investigate the effect of feeding onruminal pH. Sampling of blood and urine of all animals was done before the inductionof the acidosis, during 5 days after the onset of induction and for 18 days after theinduction (recovery period.Ruminal pH in the fistulated goats dropped to less than 5.5 during the inductionperiod, and half of the goats had diarrhea on the third day after the induction of acidosis.Acid-base parameters showed that the acid-base compensatory mechanisms wereefficient in maintaining the equilibrium. Serum Hp had a moderate increase duringthe induction period, while SAA did not change. These results suggest that Hp mightbe a potential marker for ruminal acidosis in goats.

F.H.D. González

2010-12-01

69

Protein corona composition of gold nanoparticles/nanorods affects amyloid beta fibrillation process  

Science.gov (United States)

Protein fibrillation process (e.g., from amyloid beta (A?) and ?-synuclein) is the main cause of several catastrophic neurodegenerative diseases such as Alzheimer's and Parkinson diseases. During the past few decades, nanoparticles (NPs) were recognized as one of the most promising tools for inhibiting the progress of the disease by controlling the fibrillation kinetic process; for instance, gold NPs have a strong capability to inhibit A? fibrillations. It is now well understood that a layer of biomolecules would cover the surface of NPs (so called ``protein corona'') upon the interaction of NPs with protein sources. Due to the fact that the biological species (e.g., cells and amyloidal proteins) ``see'' the protein corona coated NPs rather than the pristine coated particles, one should monitor the fibrillation process of amyloidal proteins in the presence of corona coated NPs (and not pristine coated ones). Therefore, the previously obtained data on NPs effects on the fibrillation process should be modified to achieve a more reliable and predictable in vivo results. Herein, we probed the effects of various gold NPs (with different sizes and shapes) on the fibrillation process of A? in the presence and absence of protein sources (i.e., serum and plasma). We found that the protein corona formed a shell at the surface of gold NPs, regardless of their size and shape, reducing the access of A? to the gold inhibitory surface and, therefore, affecting the rate of A? fibril formation. More specifically, the anti-fibrillation potencies of various corona coated gold NPs were strongly dependent on the protein source and their concentrations (10% serum/plasma (simulation of an in vitro milieu) and 100% serum/plasma (simulation of an in vivo milieu)).Protein fibrillation process (e.g., from amyloid beta (A?) and ?-synuclein) is the main cause of several catastrophic neurodegenerative diseases such as Alzheimer's and Parkinson diseases. During the past few decades, nanoparticles (NPs) were recognized as one of the most promising tools for inhibiting the progress of the disease by controlling the fibrillation kinetic process; for instance, gold NPs have a strong capability to inhibit A? fibrillations. It is now well understood that a layer of biomolecules would cover the surface of NPs (so called ``protein corona'') upon the interaction of NPs with protein sources. Due to the fact that the biological species (e.g., cells and amyloidal proteins) ``see'' the protein corona coated NPs rather than the pristine coated particles, one should monitor the fibrillation process of amyloidal proteins in the presence of corona coated NPs (and not pristine coated ones). Therefore, the previously obtained data on NPs effects on the fibrillation process should be modified to achieve a more reliable and predictable in vivo results. Herein, we probed the effects of various gold NPs (with different sizes and shapes) on the fibrillation process of A? in the presence and absence of protein sources (i.e., serum and plasma). We found that the protein corona formed a shell at the surface of gold NPs, regardless of their size and shape, reducing the access of A? to the gold inhibitory surface and, therefore, affecting the rate of A? fibril formation. More specifically, the anti-fibrillation potencies of various corona coated gold NPs were strongly dependent on the protein source and their concentrations (10% serum/plasma (simulation of an in vitro milieu) and 100% serum/plasma (simulation of an in vivo milieu)). Electronic supplementary information (ESI) available: Full characterization results of the nanoparticles, protein corona, and fibrillation process. See DOI: 10.1039/c4nr06009a

Mirsadeghi, Somayeh; Dinarvand, Rassoul; Ghahremani, Mohammad Hossein; Hormozi-Nezhad, Mohammad Reza; Mahmoudi, Zohreh; Hajipour, Mohammad Javad; Atyabi, Fatemeh; Ghavami, Mahdi; Mahmoudi, Morteza

2015-03-01

70

Amyloid ?-protein oligomers and Alzheimer’s disease  

OpenAIRE

The oligomer cascade hypothesis, which states that oligomers are the initiating pathologic agents in Alzheimer’s disease, has all but supplanted the amyloid cascade hypothesis, which suggested that fibers were the key etiologic agents in Alzheimer’s disease. We review here the results of in vivo, in vitro and in silico studies of amyloid ?-protein oligomers, and discuss important caveats that should be considered in the evaluation of these results. This article is divided into four secti...

Hayden, Eric Y.; Teplow, David B.

2013-01-01

71

?-amyloid oligomers and cellular prion protein in Alzheimer's disease  

OpenAIRE

Prefibrillar oligomers of the ?-amyloid peptide (A?) are recognized as potential mediators of Alzheimer's disease (AD) pathophysiology. Deficits in synaptic function, neurotoxicity, and the progression of AD have all been linked to the oligomeric A? assemblies rather than to A? monomers or to amyloid plaques. However, the molecular sites of A? oligomer action have remained largely unknown. Recently, the cellular prion protein (PrPC) has been shown to act as a functional receptor for A? ...

Gunther, Erik C.; Strittmatter, Stephen M.

2009-01-01

72

Protein corona composition of gold nanoparticles/nanorods affects amyloid beta fibrillation process.  

Science.gov (United States)

Protein fibrillation process (e.g., from amyloid beta (A?) and ?-synuclein) is the main cause of several catastrophic neurodegenerative diseases such as Alzheimer's and Parkinson diseases. During the past few decades, nanoparticles (NPs) were recognized as one of the most promising tools for inhibiting the progress of the disease by controlling the fibrillation kinetic process; for instance, gold NPs have a strong capability to inhibit A? fibrillations. It is now well understood that a layer of biomolecules would cover the surface of NPs (so called "protein corona") upon the interaction of NPs with protein sources. Due to the fact that the biological species (e.g., cells and amyloidal proteins) "see" the protein corona coated NPs rather than the pristine coated particles, one should monitor the fibrillation process of amyloidal proteins in the presence of corona coated NPs (and not pristine coated ones). Therefore, the previously obtained data on NPs effects on the fibrillation process should be modified to achieve a more reliable and predictable in vivo results. Herein, we probed the effects of various gold NPs (with different sizes and shapes) on the fibrillation process of A? in the presence and absence of protein sources (i.e., serum and plasma). We found that the protein corona formed a shell at the surface of gold NPs, regardless of their size and shape, reducing the access of A? to the gold inhibitory surface and, therefore, affecting the rate of A? fibril formation. More specifically, the anti-fibrillation potencies of various corona coated gold NPs were strongly dependent on the protein source and their concentrations (10% serum/plasma (simulation of an in vitro milieu) and 100% serum/plasma (simulation of an in vivo milieu)). PMID:25695421

Mirsadeghi, Somayeh; Dinarvand, Rassoul; Ghahremani, Mohammad Hossein; Hormozi-Nezhad, Mohammad Reza; Mahmoudi, Zohreh; Hajipour, Mohammad Javad; Atyabi, Fatemeh; Ghavami, Mahdi; Mahmoudi, Morteza

2015-03-01

73

Expression of amyloid-? protein and amyloid-? precursor protein after primary brain-stem injury in rats.  

Science.gov (United States)

Amyloid-? (A?) protein and its precursor, amyloid-? precursor protein (?-APP), have traditionally been used in the diagnosis of Alzheimer disease. Their use in diagnosis of traumatic brain injury by forensic analysis is becoming more widespread. However, to date, no reliable small animal model exists to evaluate these brain injury indicators. To address this, we have studied primary brain-stem injury in rats to assess the appearance of diffuse axonal injury in brain sections and correlate these findings with appearance of A? and relative ?-APP mRNA levels. Using an EnVision 2-step immunohistochemical staining method to measure axon diameter, we found that there was significant difference in axon diameters within the medulla oblongata and several time points after brain injury, ranging from 3 to 24 hours. In addition, mRNA expression levels of ?-APP increased following brain injury, peaking 3 hours following injury and decreasing back to baseline levels by 24 hours after injury. These results suggest that using immunohistochemistry and reverse transcription-polymerase chain reaction to detect changes in A?-associated axonal changes and ?-APP mRNA levels, respectively, can be useful for the diagnosis of diffuse axonal injury during autopsy at early time points following fatal brain injury. PMID:24949598

Yang, Shudong; Sun, Rongchao; Zhou, Zhiyi; Zhou, Jing; Liang, Jiabei; Mu, Huijun

2014-09-01

74

The serum amyloid a stimulating factor (SAASF) in the hamster  

OpenAIRE

The acute phase SAA response was studied in hamsters. An SAA-stimulating factor (SAASF) was detected in the early acute phase blood plasma of hamsters which were subcutaneously injected with casein-LPS. The latter is routinely used in our laboratory for amyloid induction in hamsters. Acute (4h) inflammatory exudates (80 per cent polymorphonuclear leukocytes) were produced by intraperitoneal injection with either casein-LPS, latex or Freund's incomplete adjuvant. Chronic inflammatory exudate m...

Hol, P. R.; Snel, F. W. J. J.; Draaijer, M.; Gruys, E.

1987-01-01

75

Complement activation by the amyloid proteins A beta peptide and beta 2-microglobulin  

DEFF Research Database (Denmark)

Complement activation (CA) has been reported to play a role in the pathogenesis of Alzheimer's disease (AD). To investigate whether CA may contribute to amyloidogenesis in general, the CA potential of different amyloid fibril proteins was tested. CA induced by A beta preparations containing soluble protein, protofilaments and some fibrils or only fibrils in a solid phase system (ELISA) was modest with a slow kinetics compared to the positive delta IgG control. Soluble A beta induced no detectable CA in a liquid phase system (complement consumption assay) while fibrillar A beta caused CA at 200 mg/ml and higher concentrations. Soluble beta 2-microglobulin (beta 2M) purified from peritoneal dialysates was found to be as potent a complement activator as A beta in both solid and liquid phase systems while beta 2M purified from urine exhibited lower activity, a difference which may be explained by differences observed in SDS-resistant oligomers and isoforms. Soluble Amyloid A-protein caused no significant CA. A beta and beta 2M activated complement via the classical pathway. The modifying influence by amyloid-associated molecules on A beta-induced CA was also investigated, but neither serum amyloid P component nor heparan sulfate did significantly alter the A beta-induced CA. The results indicate that not only fibrillar A beta but also oligomers of, in particular, beta 2M from patients with dialysis-associated amyloidosis are capable of inducing CA at supra-physiological concentrations.

Nybo, Mads; Nielsen, E H

1999-01-01

76

Induction of interleukin-23 p19 by serum amyloid A (SAA) in rheumatoid synoviocytes  

Science.gov (United States)

In this study, we investigated the roles of serum amyloid A (SAA) in T helper 17 (Th17)-related cytokine induction in rheumatoid arthritis (RA) synoviocytes. Synoviocytes isolated from rheumatoid arthritis (RA) patients were stimulated with recombinant SAA and IL-23 expression was investigated using reverse transcriptase-polymerase chain reaction and Western blot. The involvement of mitogen-activated protein kineases (MAPKs) and nuclear factor (NF)-?B in SAA-induced interleukin (IL)-23 p19 expression was investigated using pharmacological inhibitors. In RA synoviocytes, SAA induced the expression of IL-23 p19 and p40 mRNA expression. The SAA-stimulated expression of p19 was rapid (< 3 h), and insensitive to polymyxin B treatment. This SAA-stimulated expression of IL-23 p19 was inhibited completely by inhibitors of NF-?B, p38MAPK and dexamethasone. Interestingly, the SAA-induced IL-23, p19 and p40 production was accompanied by enhanced expression of IL-1?, but not transforming growth factor-?. These results indicate that SAA is a significant inducer of IL-23 and IL-1? in RA synoviocytes and potentially activates the IL-23/IL-17 pathway in the RA synovium. Our data present a novel interaction between inflammation and autoimmunity by an acute-phase protein. PMID:20840651

Migita, K; Koga, T; Torigoshi, T; Motokawa, S; Maeda, Y; Jiuchi, Y; Izumi, Y; Miyashita, T; Nakamura, M; Komori, A; Ishibashi, H

2010-01-01

77

Amyloid formation and inhibition of an all-beta protein: A study on fungal polygalacturonase  

Science.gov (United States)

Theoretically, all proteins can adopt the nanofibrillar structures known as amyloid, which contain cross-beta structures. The all-beta folded proteins are particularly interesting in this regard, since they appear to be naturally more predisposed toward this structural arrangement. In this study, methanol has been used to drive the beta-helix protein polygalacturonase (PG), toward amyloid fibril formation. Congo red absorbance, thioflavin T fluorescence, circular dichroism (CD) and transmission electron microscopy have been used to characterize this process. Similar to other all-beta proteins, PG shows a non-cooperative fibrillation mechanism, but the structural changes that are monitored by CD indicate a different pattern. Furthermore, several compounds containing aromatic components were tested as potential inhibitors of amyloid formation. Another protein predominantly composed of alpha-helices (human serum albumin) was also targeted by these ligands, in order to get an insight into their potential anti-aggregation property toward structurally different proteins. Among tested compounds, silibinin and chlorpropamide were able to considerably affect both proteins fibrillation process.

Chinisaz, Maryam; Ghasemi, Atiyeh; Larijani, Bagher; Ebrahim-Habibi, Azadeh

2014-02-01

78

Amyloid precursor protein modulates ?-catenin degradation  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The amyloid precursor protein (APP is genetically associated with Alzheimer's disease (AD. Elucidating the function of APP should help understand AD pathogenesis and provide insights into therapeutic designs against this devastating neurodegenerative disease. Results We demonstrate that APP expression in primary neurons induces ?-catenin phosphorylation at Ser33, Ser37, and Thr41 (S33/37/T41 residues, which is a prerequisite for ?-catenin ubiquitinylation and proteasomal degradation. APP-induced phosphorylation of ?-catenin resulted in the reduction of total ?-catenin levels, suggesting that APP expression promotes ?-catenin degradation. In contrast, treatment of neurons with APP siRNAs increased total ?-catenin levels and decreased ?-catenin phosphorylation at residues S33/37/T41. Further, ?-catenin was dramatically increased in hippocampal CA1 pyramidal cells from APP knockout animals. Acute expression of wild type APP or of familial AD APP mutants in primary neurons downregulated ?-catenin in membrane and cytosolic fractions, and did not appear to affect nuclear ?-catenin or ?-catenin-dependent transcription. Conversely, in APP knockout CA1 pyramidal cells, accumulation of ?-catenin was associated with the upregulation of cyclin D1, a downstream target of ?-catenin signaling. Together, these data establish that APP downregulates ?-catenin and suggest a role for APP in sustaining neuronal function by preventing cell cycle reactivation and maintaining synaptic integrity. Conclusion We have provided strong evidence that APP modulates ?-catenin degradation in vitro and in vivo. Future studies may investigate whether APP processing is necessary for ?-catenin downregulation, and determine if excessive APP expression contributes to AD pathogenesis through abnormal ?-catenin downregulation.

Chen Yuzhi

2007-12-01

79

Characterization of rat serum amyloid A4 (SAA4): A novel member of the SAA superfamily  

Science.gov (United States)

The serum amyloid A (SAA) family of proteins is encoded by multiple genes, which display allelic variation and a high degree of homology in mammals. The SAA1/2 genes code for non-glycosylated acute-phase SAA1/2 proteins, that may increase up to 1000-fold during inflammation. The SAA4 gene, well characterized in humans (hSAA4) and mice (mSaa4) codes for a SAA4 protein that is glycosylated only in humans. We here report on a previously uncharacterized SAA4 gene (rSAA4) and its product in Rattus norvegicus, the only mammalian species known not to express acute-phase SAA. The exon/intron organization of rSAA4 is similar to that reported for hSAA4 and mSaa4. By performing 5?- and 3?RACE, we identified a 1830-bases containing rSAA4 mRNA (including a GA-dinucleotide tandem repeat). Highest rSAA4 mRNA expression was detected in rat liver. In McA-RH7777 rat hepatoma cells, rSAA4 transcription was significantly upregulated in response to LPS and IL-6 while IL-1?/? and TNF? were without effect. Luciferase assays with promoter-truncation constructs identified three proximal C/EBP-elements that mediate expression of rSAA4 in McA-RH7777 cells. In line with sequence prediction a 14-kDa non-glycosylated SAA4 protein is abundantly expressed in rat liver. Fluorescence microscopy revealed predominant localization of rSAA4-GFP-tagged fusion protein in the ER. PMID:25044109

Rossmann, Christine; Windpassinger, Christian; Brunner, Daniela; Kovacevic, Alenka; Schweighofer, Natascha; Malli, Roland; Schuligoi, Rufina; Prokesch, Andreas; Kluve-Beckerman, Barbara; Graier, Wolfgang F.; Kratky, Dagmar; Sattler, Wolfgang; Malle, Ernst

2014-01-01

80

Establishment of a transgenic mouse model specifically expressing human serum amyloid A in adipose tissue.  

Science.gov (United States)

Obesity and obesity co-morbidities are associated with a low grade inflammation and elevated serum levels of acute phase proteins, including serum amyloid A (SAA). In the non-acute phase in humans, adipocytes are major producers of SAA but the function of adipocyte-derived SAA is unknown. To clarify the role of adipocyte-derived SAA, a transgenic mouse model expressing human SAA1 (hSAA) in adipocytes was established. hSAA expression was analysed using real-time PCR analysis. Male animals were challenged with a high fat (HF) diet. Plasma samples were subjected to fast protein liquid chromatography (FPLC) separation. hSAA, cholesterol and triglyceride content were measured in plasma and in FPLC fractions. Real-time PCR analysis confirmed an adipose tissue-specific hSAA gene expression. Moreover, the hSAA gene expression was not influenced by HF diet. However, hSAA plasma levels in HF fed animals (37.7±4.0 µg/mL, n?=?7) were increased compared to those in normal chow fed animals (4.8±0.5 µg/mL, n?=?10; pplasma levels in the two groups were in the same ranges as in obese and lean human subjects, respectively. In FPLC separated plasma samples, the concentration of hSAA peaked in high-density lipoprotein (HDL) containing fractions. In addition, cholesterol distribution over the different lipoprotein subfractions as assessed by FPLC analysis was similar within the two experimental groups. The established transgenic mouse model demonstrates that adipose tissue produced hSAA enters the circulation, resulting in elevated plasma levels of hSAA. This new model will enable further studies of metabolic effects of adipose tissue-derived SAA. PMID:21611116

Olsson, Maja; Ahlin, Sofie; Olsson, Bob; Svensson, Per-Arne; Ståhlman, Marcus; Borén, Jan; Carlsson, Lena M S; Sjöholm, Kajsa

2011-01-01

81

Destruxin E Decreases Beta-Amyloid Generation by Reducing Colocalization of Beta-Amyloid-Cleaving Enzyme 1 and Beta-Amyloid Protein Precursor  

OpenAIRE

Alzheimer-disease-associated beta-amyloid (A beta) is produced by sequential endoproteolysis of beta-amyloid protein precursor (beta APP): the extracellular portion is shed by cleavage in the juxtamembrane region by beta-amyloid-cleaving enzyme (BACE)/beta-secretase, after which it is cleaved by presenilin (PS)/gamma-secretase near the middle of the transmembrane domain. Thus, inhibition of either of the secretases reduces A beta generation and is a fundamental strategy for the development of...

Itoh, Naohiro; Okochi, Masayasu; Tagami, Shinji; Nishitomi, Kouhei; Nakayama, Taisuke; Yanagida, Kanta; Fukumori, Akio; Jiang, Jingwei; Mori, Kohji; Hosono, Motoko; Kikuchi, Jyunko; Nakano, Yuko; Takinami, Yoshihiko; Dohi, Keiji; Nishigaki, Atsuko

2009-01-01

82

hA molecular switch in amyloid assembly: Met35 and amyloid beta-protein oligomerization.  

OpenAIRE

Aberrant protein oligomerization is an important pathogenetic process in vivo. In Alzheimer's disease (AD), the amyloid beta-protein (Abeta) forms neurotoxic oligomers. The predominant in vivo Abeta alloforms, Abeta40 and Abeta42, have distinct oligomerization pathways. Abeta42 monomers oligomerize into pentamer/hexamer units (paranuclei) which self-associate to form larger oligomers. Abeta40 does not form these paranuclei, a fact which may explain the particularly strong linkage of Abeta42 w...

Bitan, Gal; Tarus, Bogdan; Vollers, Sabrina S.; Lashuel, Hilal A.; Condron, Margaret M.; Straub, John E.; Teplow, David B.

2003-01-01

83

Interaction of Amyloid Inhibitor Proteins with Amyloid Beta Peptides: Insight from Molecular Dynamics Simulations  

OpenAIRE

Knowledge of the detailed mechanism by which proteins such as human ?B- crystallin and human lysozyme inhibit amyloid beta (A?) peptide aggregation is crucial for designing treatment for Alzheimer's disease. Thus, unconstrained, atomistic molecular dynamics simulations in explicit solvent have been performed to characterize the A?17–42 assembly in presence of the ?B-crystallin core domain and of lysozyme. Simulations reveal that both inhibitor proteins compete with inter-peptide interac...

Das, Payel; Kang, Seung-gu; Temple, Sally; Belfort, Georges

2014-01-01

84

The Amyloid Precursor Protein Intracellular Domain-Fe65 Multiprotein Complexes: A Challenge to the Amyloid Hypothesis for Alzheimer's Disease?  

OpenAIRE

Since its proposal in 1994, the amyloid cascade hypothesis has prevailed as the mainstream research subject on the molecular mechanisms leading to the Alzheimer's disease (AD). Most of the field had been historically based on the role of the different forms of aggregation of ?-amyloid peptide (A?). However, a soluble intracellular fragment termed amyloid precursor protein (APP) intracellular domain (AICD) is produced in conjunction with A? fragments. This peptide had been shown to be highl...

Amp Rquez, Daniel A. B.; Christian González-Billault

2012-01-01

85

Protein phosphorylation regulates secretion of Alzheimer beta/A4 amyloid precursor protein.  

OpenAIRE

Extracellular deposition of the beta/A4 amyloid peptide is a characteristic feature of the brain in patients with Alzheimer disease. beta/A4 amyloid is derived from the amyloid precursor protein (APP), an integral membrane protein that exists as three major isoforms (APP695, APP751, and APP770). Secreted forms of APP found in blood plasma and cerebrospinal fluid arise by proteolytic cleavage of APP within the beta/A4 amyloid domain, precluding the possibility of amyloidogenesis for that popul...

Caporaso, G. L.; Gandy, S. E.; Buxbaum, J. D.; Ramabhadran, T. V.; Greengard, P.

1992-01-01

86

Characterization of serum amyloid A (SAA) in rainbow trout using a new monoclonal antibody  

DEFF Research Database (Denmark)

Serum amyloid A (SAA) is an integral part of the innate immune response in mammals and considered to be important during the acute phase response. The present study was undertaken to elucidate the role of SAA protein in the innate immune response of rainbow trout. A monoclonal antibody raised against a recombinant peptide of rainbow trout SAA was characterized using Western blot, dot blot, ELISA and immunohistochemistry. SAA association with high density lipoprotein (HDL) complicated band identification in Western blot, but delipidization of the SAA-HDL isolate highly increased the quality of reaction in the western blot. Rainbow trout fry (87 days post hatch) infected with Yersinia ruckeri showed a significant up-regulation of the SAA gene at 72 h post infection with an increase until 96 h post infection. Non-significant up-regulations were seen at earlier time points i.e. 4 and 24 h. The expression pattern of SAA significantly correlated to the immunohistochemical analysis of the infected fry. A weak staining was seen in liver tissue at 4 h post infection which increased in intensity during the course of infection i.e. 24, 72 and 96 h post infection.

Kania, Per Walter; Chettri, Jiwan Kumar

2014-01-01

87

Characterization of serum amyloid A (SAA) in rainbow trout using a new monoclonal antibody.  

Science.gov (United States)

Serum amyloid A (SAA) is an integral part of the innate immune response in mammals and considered to be important during the acute phase response. The present study was undertaken to elucidate the role of SAA protein in the innate immune response of rainbow trout. A monoclonal antibody raised against a recombinant peptide of rainbow trout SAA was characterized using Western blot, dot blot, ELISA and immunohistochemistry. SAA association with high density lipoprotein (HDL) complicated band identification in Western blot, but delipidization of the SAA-HDL isolate highly increased the quality of reaction in the western blot. Rainbow trout fry (87 days post hatch) infected with Yersinia ruckeri showed a significant up-regulation of the SAA gene at 72 h post infection with an increase until 96 h post infection. Non-significant up-regulations were seen at earlier time points i.e. 4 and 24 h. The expression pattern of SAA significantly correlated to the immunohistochemical analysis of the infected fry. A weak staining was seen in liver tissue at 4 h post infection which increased in intensity during the course of infection i.e. 24, 72 and 96 h post infection. PMID:25149592

Kania, Per W; Chettri, Jiwan K; Buchmann, Kurt

2014-10-01

88

Serum protein capillary electrophoresis and measurement of acute phase proteins in a captive cheetah (Acinonyx jubatus) population.  

Science.gov (United States)

Renal and gastrointestinal pathologies are widespread in the captive cheetah (Acinonyx jubatus) population but are often diagnosed at a late stage, because diagnostic tools are limited to the evaluation of clinical signs or general blood examination. Presently, no data are available on serum proteins and acute-phase proteins in cheetahs during health or disease, although they might be important to improve health monitoring. This study aimed to quantify serum proteins by capillary electrophoresis in 80 serum samples from captive cheetahs, categorized according to health status and disease type. Moreover, serum amyloid A concentrations were measured via a turbidimetric immunoassay validated in domestic cats, whereas haptoglobin and C-reactive protein were determined by non-species-specific functional tests. Cheetahs classified as healthy had serum protein and acute phase protein concentrations within reference ranges for healthy domestic cats. In contrast, unhealthy cheetahs had higher (P P = 0.020), alpha2-globulin (P P = 0.001) concentrations in cheetahs suffering from chronic kidney disease were significantly greater compared to the reportedly healthy cheetahs. Our study indicates that serum proteins in the cheetah can be analyzed by routine capillary electrophoresis, whereas acute-phase proteins can be measured using available immunoassays or non-species-specific techniques, which are also likely to be applicable in other exotic felids. Moreover, results suggest that serum amyloid A and haptoglobin are important acute-phase proteins in the diseased cheetah and highlight the need to evaluate their role as early-onset markers for disease. PMID:25314816

Depauw, Sarah; Delanghe, Joris; Whitehouse-Tedd, Katherine; Kjelgaard-Hansen, Mads; Christensen, Michelle; Hesta, Myriam; Tugirimana, Pierrot; Budd, Jane; Dermauw, Veronique; Janssens, Geert P J

2014-09-01

89

Localized and efficient curli nucleation requires the chaperone-like amyloid assembly protein CsgF  

OpenAIRE

Elucidation of the early events in amyloidogenesis is key to understanding the pathology of, and developing therapies for, amyloid diseases. Critical informants about these early events are amyloid assembly proteins that facilitate the transition from monomer to amyloid fiber. Curli are a functional amyloid whose in vivo polymerization requires a dedicated nucleator protein, CsgB, and an assembly protein, CsgF. Here we demonstrate that without CsgF, curli subunits are released from the cell i...

Nenninger, Ashley A.; Robinson, Lloyd S.; Hultgren, Scott J.

2009-01-01

90

Piezoelectric microcantilever serum protein detector  

Science.gov (United States)

The development of a serum protein detector will provide opportunities for better screening of at-risk cancer patients, tighter surveillance of disease recurrence and better monitoring of treatment. An integrated system that can process clinical samples for a number of different types of biomarkers would be a useful tool in the early detection of cancer. Also, screening biomarkers such as antibodies in serum would provide clinicians with information regarding the patient's response to treatment. Therefore, the goal of this study is to develop a sensor which can be used for rapid, all-electrical, real-time, label-fee, in-situ, specific quantification of cancer markers, e.g., human epidermal receptor 2 (Her2) or antibodies, in serum. To achieve this end, piezoelectric microcantilever sensors (PEMS) were constructed using an 8 mum thick lead magnesium niobate-lead titanate (PMN-PT) freestanding film as the piezoelectric layer. The desired limit of detection is on the order of pg/mL. In order to achieve this goal the higher frequency lateral extension modes were used. Also, as the driving and sensing of the PEMS is electrical, the PEMS must be insulated in a manner that allows it to function in aqueous solutions. The insulation layer must also be compatible with standardized bioconjugation techniques. Finally, detection of both cancer antigens and antibodies in serum was carried out, and the results were compared to a standard commercialized protocol. PEMS have demonstrated the capability of detecting Her2 at a concentration of 5 pg/mL in diluted human serum (1:40) in less than 1 hour. The approach can be easily translated into the clinical setting because the sensitivity is more than sufficient for monitoring prognosis of breast cancer patients. In addition to Her2 detection, antibodies in serum were assayed in order to demonstrate the feasibility of monitoring the immune response for antibody-dependent cellular cytotoxicity (ADCC) in patients on antibody therapies such as Herceptin and Cetuximab. The PEMS displayed a limit of detection of 100 fg/mL, which was 100 times lower than the current methods of protein detection in serum, such as ELISA. Furthermore, the sensitivity of the PEMS device allows it to be capable of determining the dissociation constant, K d, of selective receptors such as antibodies. Using the dose response trials of Her2, Kd has been deduced for H3 scFv, and Herceptin, a commercial antibody specific for Her2.

Capobianco, Joseph A.

91

Serum amyloid A promotes osteosarcoma invasion via upregulating ?v?3 integrin.  

Science.gov (United States)

Serum amyloid A (SAA) is regarded as an important acute phase protein involved in tumor progression and metastasis. However, at present there is no evidence of its involvement in osteosarcoma. The present study aimed to investigate the effect of SAA on the invasion of osteosarcoma cells. The effects of SAA on the migration and invasion of osteosarcoma cells were detected using scratch wound healing and transwell assays, respectively. The expression of ?v?3 integrin was detected at the protein and mRNA levels in U2OS cells. Agonists, inhibitors or siRNA of formyl peptide receptor like?1 (FPRL?1), mitogen?activated protein kinases and ?v?3 integrin were used to investigate the mechanism underlying the effects of SAA on the regulation of U2OS cell migration and invasion. The present study revealed that SAA promoted osteosarcoma cell migration and invasion. SAA upregulated the expression of ?v?3 integrin in a concentration? and time?dependent manner. When inhibiting ?v?3 integrin with its antagonist, the migration and invasion abilities of the U2OS cells were markedly inhibited. SAA?induced ?v?3 integrin production was significantly downregulated by inhibiting FPRL?1 with siRNA and inhibitors. The present study also found that extracellular signal?regulated kinase (ERK) 1/2, but not c?Jun N?terminal kinase or p38, was important in this process. These findings demonstrated that SAA regulated osteosarcoma cell migration and invasion via the FPRL?1/ERK/?v?3 integrin pathway. PMID:25323768

Ren, Peng; Sun, Deshun; Xin, Dajiang; Ma, Wanli; Chen, Peng; Gao, Hongwei; Zhang, Shouqiang; Gong, Mingzhi

2014-12-01

92

Engineering Amyloid Fibrils from ?-Solenoid Proteins for Biomaterials Applications.  

Science.gov (United States)

Nature provides numerous examples of self-assembly that can potentially be implemented for materials applications. Considerable attention has been given to one-dimensional cross-? or amyloid structures that can serve as templates for wire growth or strengthen materials such as glue or cement. Here, we demonstrate controlled amyloid self-assembly based on modifications of ?-solenoid proteins. They occur naturally in several contexts (e.g., antifreeze proteins, drug resistance proteins) but do not aggregate in vivo due to capping structures or distortions at their ends. Removal of these capping structures and regularization of the ends of the spruce budworm and rye grass antifreeze proteins yield micron length amyloid fibrils with predictable heights, which can be a platform for biomaterial-based self-assembly. The design process, including all-atom molecular dynamics simulations, purification, and self-assembly procedures are described. Fibril formation with the predicted characteristics is supported by evidence from thioflavin-T fluorescence, circular dichroism, dynamic light scattering, and atomic force microscopy. Additionally, we find evidence for lateral assembly of the modified spruce budworm antifreeze fibrils with sufficient incubation time. The kinetics of polymerization are consistent with those for other amyloid formation reactions and are relatively fast due to the preformed nature of the polymerization nucleus. PMID:25562726

Peralta, Maria D R; Karsai, Arpad; Ngo, Alice; Sierra, Catherine; Fong, Kai T; Hayre, Natha Robert; Mirzaee, Nima; Ravikumar, Krishnakumar Mayuram; Kluber, Alexander J; Chen, Xi; Liu, Gang-Yu; Toney, Michael D; Singh, Rajiv R; Cox, Daniel Lee

2015-01-27

93

Enhanced degradation of amyloid AA proteins by enzyme activation: a possible model for a therapeutic approach  

International Nuclear Information System (INIS)

The capacity of plasminogen from human serum to degrade amyloid AA protein was tested using radiolabelled protein AA coupled to cyanogen bromide activated Sepharose 6 MB as substrate. Protein AA degrading activity was determined in fractions of normal human serum separated by Sephadex G 150. Each fraction was tested in the presence and absence of the plasminogen activator streptokinase. The AA degrading activity was markedly increased in fractions in which plasminogen activation had occurred. These fractions were also the same as those showing the presence of plasminogen as demonstrated by reaction with a specific anti-plasminogen antiserum. Moreover, the increase in AA degrading activity could be inhibited with antibodies to plasminogen. AA degrading activity could also be enhanced in whole human plasma by streptokinase activation

94

The beta-amyloid domain is essential for axonal sorting of amyloid precursor protein.  

OpenAIRE

We have analysed the axonal sorting signals of amyloid precursor protein (APP). Wild-type and mutant versions of human APP were expressed in hippocampal neurons using the Semliki forest virus system. We show that wild-type APP and mutations implicated in Alzheimer's disease and another brain beta-amyloidosis are sorted to the axon. By analysis of deletion mutants we found that the membrane-inserted APP ectodomain but not the cytoplasmic tail is required for axonal sorting. Systematic deletion...

Tienari, P. J.; Strooper, B.; Ikonen, E.; Simons, M.; Weidemann, A.; Czech, C.; Hartmann, T.; Ida, N.; Multhaup, G.; Masters, C. L.; Leuven, F.; Beyreuther, K.; Dotti, C. G.

1996-01-01

95

Zn2+ interaction with Alzheimer amyloid beta protein calcium channels.  

OpenAIRE

The Alzheimer disease 40-residue amyloid beta protein (AbetaP[1-40]) forms cation-selective channels across acidic phospholipid bilayer membranes with spontaneous transitions over a wide range of conductances ranging from 40 to 4000 pS. Zn2+ has been reported to bind to AbetaP[1-40] with high affinity, and it has been implicated in the formation of amyloid plaques. We now report the functional consequences of such Zn2+ binding for the AbetaP[1-40] channel. Provided the AbetaP[1-40] channel is...

Arispe, N.; Pollard, H. B.; Rojas, E.

1996-01-01

96

Interaction of Amyloid Inhibitor Proteins with Amyloid Beta Peptides: Insight from Molecular Dynamics Simulations  

Science.gov (United States)

Knowledge of the detailed mechanism by which proteins such as human ?B- crystallin and human lysozyme inhibit amyloid beta (A?) peptide aggregation is crucial for designing treatment for Alzheimer's disease. Thus, unconstrained, atomistic molecular dynamics simulations in explicit solvent have been performed to characterize the A?17–42 assembly in presence of the ?B-crystallin core domain and of lysozyme. Simulations reveal that both inhibitor proteins compete with inter-peptide interaction by binding to the peptides during the early stage of aggregation, which is consistent with their inhibitory action reported in experiments. However, the A? binding dynamics appear different for each inhibitor. The binding between crystallin and the peptide monomer, dominated by electrostatics, is relatively weak and transient due to the heterogeneous amino acid distribution of the inhibitor surface. The crystallin-bound A? oligomers are relatively long-lived, as they form more extensive contact surface with the inhibitor protein. In contrast, a high local density of arginines from lysozyme allows strong binding with A? peptide monomers, resulting in stable complexes. Our findings not only illustrate, in atomic detail, how the amyloid inhibitory mechanism of human ?B-crystallin, a natural chaperone, is different from that of human lysozyme, but also may aid de novo design of amyloid inhibitors. PMID:25422897

Das, Payel; Kang, Seung-gu; Temple, Sally; Belfort, Georges

2014-01-01

97

AMYPdb: A database dedicated to amyloid precursor proteins  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Misfolding and aggregation of proteins into ordered fibrillar structures is associated with a number of severe pathologies, including Alzheimer's disease, prion diseases, and type II diabetes. The rapid accumulation of knowledge about the sequences and structures of these proteins allows using of in silico methods to investigate the molecular mechanisms of their abnormal conformational changes and assembly. However, such an approach requires the collection of accurate data, which are inconveniently dispersed among several generalist databases. Results We therefore created a free online knowledge database (AMYPdb dedicated to amyloid precursor proteins and we have performed large scale sequence analysis of the included data. Currently, AMYPdb integrates data on 31 families, including 1,705 proteins from nearly 600 organisms. It displays links to more than 2,300 bibliographic references and 1,200 3D-structures. A Wiki system is available to insert data into the database, providing a sharing and collaboration environment. We generated and analyzed 3,621 amino acid sequence patterns, reporting highly specific patterns for each amyloid family, along with patterns likely to be involved in protein misfolding and aggregation. Conclusion AMYPdb is a comprehensive online database aiming at the centralization of bioinformatic data regarding all amyloid proteins and their precursors. Our sequence pattern discovery and analysis approach unveiled protein regions of significant interest. AMYPdb is freely accessible 1.

Delamarche Christian

2008-06-01

98

Alzheimer amyloid beta-protein precursor in sperm development.  

OpenAIRE

We prepared antisera to both the N and C termini of amyloid beta-protein precursor (APP). Both antisera labeled 110 to 140 kd proteins from rat testis by immunoblotting. Northern blot analysis using oligonucleotide probes complementary to respective APPs showed that APPs expressed in rat testis contained Kunitz-type protease inhibitor domains. Immunocytochemically brain APP was localized in neurons and their processes. During sperm formation, APPs labeled by both antisera were localized only ...

Shoji, M.; Kawarabayashi, T.; Harigaya, Y.; Yamaguchi, H.; Hirai, S.; Kamimura, T.; Sugiyama, T.

1990-01-01

99

Purification and Aggregation of the Amyloid Precursor Protein Intracellular Domain  

OpenAIRE

Amyloid precursor protein (APP) is a type I transmembrane protein associated with the pathogenesis of Alzheimer's disease (AD). APP is characterized by a large extracellular domain and a short cytosolic domain termed the APP intracellular domain (AICD). During maturation through the secretory pathway, APP can be cleaved by proteases termed ?, ?, and ?-secretases1. Sequential proteolytic cleavage of APP with ? and ?-secretases leads to the production of a small proteolytic peptide, termed...

El Ayadi, Amina; Stieren, Emily S.; Barral, Jose? M.; Oberhauser, Andres F.; Boehning, Darren

2012-01-01

100

Amino Acid Position-specific Contributions to Amyloid ?-Protein Oligomerization*  

OpenAIRE

Understanding the structural and assembly dynamics of the amyloid ?-protein (A?) has direct relevance to the development of therapeutic agents for Alzheimer disease. To elucidate these dynamics, we combined scanning amino acid substitution with a method for quantitative determination of the A? oligomer frequency distribution, photo-induced cross-linking of unmodified proteins (PICUP), to perform “scanning PICUP.” Tyr, a reactive group in PICUP, was substituted at position 1, 10, 20, 30...

Maji, Samir K.; Ogorzalek Loo, Rachel R.; Inayathullah, Mohammed; Spring, Sean M.; Vollers, Sabrina S.; Condron, Margaret M.; Bitan, Gal; Loo, Joseph A.; Teplow, David B.

2009-01-01

101

A carbon nanotube metal semiconductor field effect transistor-based biosensor for detection of amyloid-beta in human serum.  

Science.gov (United States)

We have developed a carbon nanotube (CNT) film-based biosensor with a metal semiconductor field effect transistor structure (MESFET). A gold top gate was deposited on the middle of the CNT channel and probe antibodies were immobilized on the gold top gate with an antibody-binding protein, protein G or Escherichia coli outer membrane (OM) with autodisplayed Z-domains of protein A. These CNT-MESFET biosensors exhibited a higher sensitivity than the CNT-FET biosensor with probe antibodies immobilized using a chemical linker, since the orientation of immobilized antibodies was controlled by the antibody-binding proteins. In addition, nonspecific binding was effectively inhibited by E. coli OM. Using the CNT-MESFET biosensors with E. coli OM containing Z domain, we detected amyloid-? (A?) in human serum, one of the biomarkers for early diagnosis of Alzheimer's disease. A? at the level of 1 pg/mL in human serum could be measured in real-time and without labeling, which was lower than a limit of detection for plasma A? using an enzyme-linked immune sorbent assay. These results suggested that our CNT-MESFET biosensors might be applicable for an early diagnosis of Alzheimer's disease. PMID:23891796

Oh, Jeseung; Yoo, Gu; Chang, Young Wook; Kim, Hyung Joon; Jose, Joachim; Kim, Eosu; Pyun, Jae-Chul; Yoo, Kyung-Hwa

2013-12-15

102

Acute phase protein concentrations in serum and milk from healthy cows, cows with clinical mastitis and cows with extramammary inflammatory conditions  

DEFF Research Database (Denmark)

The concentrations of the two acute phase proteins, serum amyloid A and haptoglobin, in serum and milk were compared in 10 cows with clinical mastitis, 11 cows with extramammary inflammatory conditions and 10 clinically healthy control cows. The concentrations of both acute phase proteins were higher in the serum and milk of the cows with mastitis than in the cows in the other two groups. Four of the cows with extramammary inflammatory conditions had serum amyloid A concentrations in serum above 100 mug/ml, but negligible concentrations in milk, indicating that a pathogen must be present in the mammary gland for serum amyloid A to accumulate in milk. The acute phase protein concentrations in milk increased significantly with increasing somatic cell count, suggesting that they may be indicators of the severity of an infection.

Nielsen, B.H.; Jacobsen, S.

2004-01-01

103

Administration of perioperative penicillin reduces postoperative serum amyloid A response in horses being castrated standing  

DEFF Research Database (Denmark)

Objectives: To compare postoperative in?ammatory responses in horses administered perioperative procaine penicillin and those not administered penicillin using acute phase protein serum amyloid A (SAA) as a marker of in?ammation. Study Design: Randomized clinical trial. Animals: Stallions (n = 50) castrated under ?eld conditions. Methods: SAA concentrations were determined on days 0, 3, and 8. Six horses were subsequently excluded because of elevated SAA concentrations on day 0. Of the remaining 50 horses, 26 were administered nonsteroidal anti-in?ammatory drug (NSAID) therapy and 24 were administered NSAID and 25,000 U/kg procaine penicillin on day 0, 1, and 2. Results: SAA concentrations increased signi?cantly from preoperative levels in both groups, and on day 8 concentrations were signi?cantly (P o .02) higher in horses administered only NSAID than in those administered procaine penicillin and NSAID. Infectious complications occurred more frequently (P o .01) in horses with preoperatively elevated SAA concentrations (the excluded horses) than in horses with normal preoperative SAA concentrations (the included horses). Conclusions: Perioperative antimicrobial therapy reduced the postoperative SAA response, suggesting that bacteria were present in the surgical wound and contributed to in?ammation after castration. Horses with elevated preoperative SAA concentrations developed infectious complications more often than horses with normal preoperative SAA concentrations. Clinical Relevance: Administration of antimicrobials may be important in horses being castrated standing under ?eld conditions. Increased SAA concentrations seem to be an indicator of increased surgical risk in horses and may be useful before elective surgery for planning.

Busk, Peter; Jacobsen, Stine

2010-01-01

104

Ribonuclease A suggests how proteins self-chaperone against amyloid fiber formation  

OpenAIRE

Genomic analyses have identified segments with high fiber-forming propensity in many proteins not known to form amyloid. Proteins are often protected from entering the amyloid state by molecular chaperones that permit them to fold in isolation from identical molecules; but, how do proteins self-chaperone their folding in the absence of chaperones? Here, we explore this question with the stable protein ribonuclease A (RNase A). We previously identified fiber-forming segments of amyloid-related...

Teng, Poh K.; Anderson, Natalie J.; Goldschmidt, Lukasz; Sawaya, Michael R.; Sambashivan, Shilpa; Eisenberg, David

2011-01-01

105

Small Heat Shock Proteins Potentiate Amyloid Dissolution by Protein Disaggregases from Yeast and Humans  

OpenAIRE

The authors define how small heat-shock proteins synergize to regulate the assembly and disassembly of a beneficial prion, and then they exploit this knowledge to identify the human amyloid depolymerase.

Duennwald, Martin L.; Echeverria, Analisa; Shorter, James

2012-01-01

106

Amyloid protein and neurofibrillary tangles coexist in the same neuron in Alzheimer disease.  

OpenAIRE

In Alzheimer disease, paired helical filaments accumulate in the neuron, and amyloid fibers are found in the extracellular space in the neuropil and brain vessels. Amyloid and paired helical filaments are morphologically distinct. Although messenger RNA that encodes the amyloid has also been shown in several tissues, including brain, the intracellular expression of the protein has not been observed. By using monoclonal antibodies to a synthetic amyloid beta peptide, the present study demonstr...

Grundke-iqbal, I.; Iqbal, K.; George, L; Tung, Y. C.; Kim, K. S.; Wisniewski, H. M.

1989-01-01

107

Overexpression of Heparanase Lowers the Amyloid Burden in Amyloid-? Precursor Protein Transgenic Mice.  

Science.gov (United States)

Heparan sulfate (HS) and HS proteoglycans (HSPGs) colocalize with amyloid-? (A?) deposits in Alzheimer disease brain and in A? precursor protein (A?PP) transgenic mouse models. Heparanase is an endoglycosidase that specifically degrades the unbranched glycosaminoglycan side chains of HSPGs. The aim of this study was to test the hypothesis that HS and HSPGs are active participators of A? pathogenesis in vivo. We therefore generated a double-transgenic mouse model overexpressing both human heparanase and human A?PP harboring the Swedish mutation (tgHpa*Swe). Overexpression of heparanase did not affect A?PP processing because the steady-state levels of A?1-40, A?1-42, and soluble A?PP ? were the same in 2- to 3-month-old double-transgenic tgHpa*Swe and single-transgenic tgSwe mice. In contrast, the Congo red-positive amyloid burden was significantly lower in 15-month-old tgHpa*Swe brain than in tgSwe brain. Likewise, the A? burden, measured by A?x-40 and A?x-42 immunohistochemistry, was reduced significantly in tgHpa*Swe brain. The intensity of HS-stained plaques correlated with the A?x-42 burden and was reduced in tgHpa*Swe mice. Moreover, the HS-like molecule heparin facilitated A?1-42-aggregation in an in vitro Thioflavin T assay. The findings suggest that HSPGs contribute to amyloid deposition in tgSwe mice by increasing A? fibril formation because heparanase-induced fragmentation of HS led to a reduced amyloid burden. Therefore, drugs interfering with A?-HSPG interactions might be a potential strategy for Alzheimer disease treatment. PMID:25548284

Jendresen, Charlotte B; Cui, Hao; Zhang, Xiao; Vlodavsky, Israel; Nilsson, Lars N G; Li, Jin-Ping

2015-02-20

108

Serum amyloid A1 isoforms display different efficacy at Toll-like receptor 2 and formyl peptide receptor 2.  

Science.gov (United States)

Serum amyloid A (SAA) is a major acute-phase protein and a precursor of amyloid A, the deposit of which leads to amyloidosis. Different alleles exist in SAA1, a predominant form of the human SAA gene family. Emerging evidence has shown correlations between these alleles and diseases including familiar Mediterranean fever and amyloidosis. However, it remains unclear how the proteins encoded by these SAA1 alleles act differently. Here we report the characterization of proteins encoded by SAA1.1, SAA1.3, and SAA1.5, in comparison to that encoded by SAA2.2, for their preference of the SAA receptors including formyl peptide receptor 2 (FPR2) and Toll-like receptor 2 (TLR2). SAA1.1 was more efficacious than SAA1.3 and SAA1.5 but equally efficacious to SAA2.2 in calcium mobilization and chemotaxis assays, which measure the activation of the G protein-coupled FPR2. In agreement with this, SAA1.1 and SAA2.2 induced more robust phosphorylation of ERK than SAA1.3 and SAA1.5. Only small differences were observed between the SAA1 proteins tested and SAA2.2 in TLR2-dependent NF-?B luciferase reporter assay. In comparison, SAA1.3 was most effective in stimulating ERK and p38 MAPK phosphorylation. Using bone marrow-derived macrophages from C57BL/10ScN (Tlr4lps-del) mice, we examined the SAA isoforms for their induction of selected pro- and anti-inflammatory cytokines. SAA1.3 was most potent in the induction of TNF? and IL-1rn, whereas SAA1.5 induced robust IL-10 expression. These results show differences of the SAA1 isoforms in their selectivity for the SAA receptors, which may affect their roles in modulating inflammation and immunity. PMID:25154907

Chen, Mingjie; Zhou, Huibing; Cheng, Ni; Qian, Feng; Ye, Richard D

2014-12-01

109

Post-transcriptional regulation of amyloid precursor protein by microRNAs and RNA binding proteins  

OpenAIRE

Amyloid Precursor Protein (APP) and its proteolytic product amyloid beta (A?) are critical in the pathogenesis of Alzheimer's Disease (AD). APP gene duplication and transcriptional upregulation are linked to AD. In addition, normal levels of APP appear to be required for some physiological functions in the developing brain. Several studies in mammalian cell lines and primary neuron cultures indicate that RNA binding proteins and microRNAs interacting with regulatory regions of the APP mRNA m...

Ruberti, Francesca; Barbato, Christian; Cogoni, Carlo

2010-01-01

110

Human amyloid beta protein gene locus: HaeIII RFLP  

Energy Technology Data Exchange (ETDEWEB)

A 2.2 kb EcoRI-EcoRI fragment from the 5{prime} end of the human amyloid beta protein cDNA was isolated from a human fibroblast cDNA library and subcloned into pGEM3. HaeIII (GGCC) detects 6 invariant bands at 0.5 kb, 1.0 kb, 1.1 kb, 1.3 kb, 1.4 kb and 1.6 kb and a two-allele polymorphism with bands at either 1.9 kb or 2.1 kb. Its frequency was studied in 50 North Americans. Human amyloid beta protein gene mapped to the long arm of chromosome 21 (21q11.2-21q21) by Southern blot analysis of human-rodent somatic cell hybrids. Co-dominant segregation was observed in two families (15 individuals).

Taylor, J.E.; Gonzalez-DeWhitt, P.A.; Fuller, F.; Cordell, B.; Frossard, P.M. (California Biotechnology Inc., Mountain View (USA)); Tinklenberg, J.R.; Davies, H.D.; Eng, L.F.; Yesavage, J.A. (Stanford Univ. School of Medicine, Palo Alto, CA (USA))

1988-07-25

111

LINGO-1 promotes lysosomal degradation of amyloid-? protein precursor  

Science.gov (United States)

Sequential proteolytic cleavages of amyloid-? protein precursor (A?PP) by ?-secretase and ?-secretase generate amyloid ? (A?) peptides, which are thought to contribute to Alzheimer's disease (AD). Much of this processing occurs in endosomes following endocytosis of A?PP from the plasma membrane. However, this pathogenic mode of processing A?PP may occur in competition with lysosomal degradation of A?PP, a common fate of membrane proteins trafficking through the endosomal system. Following up on published reports that LINGO-1 binds and promotes the amyloidogenic processing of A?PP we have examined the consequences of LINGO-1/A?PP interactions. We report that LINGO-1 and its paralogs, LINGO-2 and LINGO-3, decrease processing of A?PP in the amyloidogenic pathway by promoting lysosomal degradation of A?PP. We also report that LINGO-1 levels are reduced in AD brain, representing a possible pathogenic mechanism stimulating the generation of A? peptides in AD. PMID:25758563

de Laat, Rian; Meabon, James S.; Wiley, Jesse C.; Hudson, Mark P.; Montine, Thomas J.; Bothwell, Mark

2015-01-01

112

LINGO-1 promotes lysosomal degradation of amyloid-? protein precursor.  

Science.gov (United States)

Sequential proteolytic cleavages of amyloid-? protein precursor (A?PP) by ?-secretase and ?-secretase generate amyloid ? (A?) peptides, which are thought to contribute to Alzheimer's disease (AD). Much of this processing occurs in endosomes following endocytosis of A?PP from the plasma membrane. However, this pathogenic mode of processing A?PP may occur in competition with lysosomal degradation of A?PP, a common fate of membrane proteins trafficking through the endosomal system. Following up on published reports that LINGO-1 binds and promotes the amyloidogenic processing of A?PP we have examined the consequences of LINGO-1/A?PP interactions. We report that LINGO-1 and its paralogs, LINGO-2 and LINGO-3, decrease processing of A?PP in the amyloidogenic pathway by promoting lysosomal degradation of A?PP. We also report that LINGO-1 levels are reduced in AD brain, representing a possible pathogenic mechanism stimulating the generation of A? peptides in AD. PMID:25758563

de Laat, Rian; Meabon, James S; Wiley, Jesse C; Hudson, Mark P; Montine, Thomas J; Bothwell, Mark

2015-01-01

113

Pharmacological targeting of the ?-amyloid precursor protein intracellular domain  

OpenAIRE

Amyloid precursor protein (APP) intracellular domain (AICD) is a product of APP processing with transcriptional modulation activity, whose overexpression causes various Alzheimer's disease (AD)-related dysfunctions. Here we report that 1-(3?,4?-dichloro-2-fluoro[1,1?-biphenyl]-4-yl)-cyclopropanecarboxylic acid) (CHF5074), a compound that favorably affects neurodegeneration, neuroinflammation and memory deficit in transgenic mouse models of AD, interacts with the AICD and impairs its nuc...

Caterina Branca; Ilenia Sarnico; Roberta Ruotolo; Annamaria Lanzillotta; Arturo Roberto Viscomi; Marina Benarese; Vanessa Porrini; Luca Lorenzini; Laura Calzà; Bruno Pietro Imbimbo; Simone Ottonello; Marina Pizzi

2014-01-01

114

Amyloid precursor protein controls cholesterol turnover needed for neuronal activity  

OpenAIRE

Perturbation of lipid metabolism favours progression of Alzheimer disease, in which processing of Amyloid Precursor Protein (APP) has important implications. APP cleavage is tightly regulated by cholesterol and APP fragments regulate lipid homeostasis. Here, we investigated whether up or down regulation of full-length APP expression affected neuronal lipid metabolism. Expression of APP decreased HMG-CoA reductase (HMGCR)-mediated cholesterol biosynthesis and SREBP mRNA levels, while its down ...

Pierrot, Nathalie; Tyteca, Donatienne; D Auria, Ludovic; Dewachter, Ilse; Gailly, Philippe; Hendrickx, Aure?lie; Tasiaux, Bernadette; Haylani, Laetitia El; Muls, Nathalie; N Kuli, Francisca; Laquerrie?re, Annie; Demoulin, Jean-baptiste; Campion, Dominique; Brion, Jean-pierre; Courtoy, Pierre J.

2013-01-01

115

Investigation of the solubility and the potentials for purification of serum amyloid A (SAA) from equine acute phase serum : a pilot study  

DEFF Research Database (Denmark)

BACKGROUND: Serum amyloid A (SAA) is useful as a diagnostic marker of systemic inflammation in horses, but only heterologous assays based on non-equine calibration and standardization are available for measurements of equine SAA. More accurate measurements could be obtained using purified species-specific SAA in native conformation for assay calibration and standardization. Further knowledge about the biochemical properties of SAA would facilitate a future production of native species-specific calibration material Therefore, the aim of the study was an investigation of the solubility and potentials for purification of equine SAA based on biochemical properties.Freeze dried equine acute phase serum was dissolved in 70% 2-propanol, 8 M urea, and milli-Q water, respectively. Supercritical fluid extraction (SFE), size-exclusive chromatography (FPLC-SEC), and preparative isoelectric focusing (IEF) were performed in the attempt to purify. Immunostaining of IEF blots were used for isoform-specific detection of SAA in the preparations and purity was assessed by silverstained SDS-PAGE. FINDINGS: SAA was soluble in 70% 2-propanol, 8 M urea and Milli-Q water. SAA was not separated in the lipophilic or ampipathic fractions following SFE. SAA was included in a FPLC-SEC-fraction of 237 kDa, despite the molecular weight known to be much smaller, suggesting binding to other serum constituents. SAA precipitated following separation of other serum proteins by preparative IEF. DISCUSSION: No effective purification of SAA was achieved in the present study, but findings important for future investigations were made. The study suggested that SAA is not exclusively hydrophobic, but appears less hydrophobic when interacting with other serum components. These results suggest more complex aspects of solubility than previously believed, and indicate potentials for purification of native SAA.

Christensen, Michelle BrØnniche; SØrensen, Jens Christian

2013-01-01

116

Protein Interactions between Fe65, the LDL receptor-related protein and the amyloid precursor protein  

OpenAIRE

The adapter protein, Fe65 has been proposed to be the link between the intracellular domains of the amyloid precursor protein, APP (AICD) and the LDL receptor-related protein (LRP-CT). Functional linkage between these two proteins has been established and mutations within LRP-CT affect the amount of A? produced from APP. Previous work showed that the AICD binds to the protein interaction domain 2 (PID2) of Fe65. Although the structure of PID1 was solved recently all attempts to demonstrate L...

Mulvihill, Melinda; Guttman, Miklos; Komives, Elizabeth A.

2011-01-01

117

Protein Polymers and Amyloids : Focus on ?1-Antitrypsin  

DEFF Research Database (Denmark)

Several human disorders are caused by a common general disease mechanism arising from abnormal folding and aggregation of the underlying protein. These include the prevalent dementias like Alzheimer’s and Parkinson’s, where accumulation of protein fibrillar structures, known as amyloid fibrils, is a general hallmark. They also include the ?1-antitrypsin deficiency, where disease-causing mutations in the serine protease inhibitor, ?1-antitrypsin (?1AT), leads to accumulation of the aberrant protein in the liver of these patients. The native metastable structure of ?1AT constitutes a molecular trap that inhibits its target protease through a large conformational change but mutations compromise this function and cause premature structural collapse into hyperstable polymers. Understanding the conformational disorders at a molecular level is not only important for our general knowledge on protein folding and misfolding but also for rationalizing efficient therapeutic strategies to ameliorate the associated disease. In this work, we focussed on the C-terminal part of ?1AT to understand its role in the disease-causing polymerization events and to investigate the amyloid fibril formation of a proteolytically generated fragment from here. To enable a detailed structural analysis by Nuclear Magnetic Resonance Spectroscopy an in vitro ligation procedure was established that reconstituted ?1AT from two separate fragments. In this way, it would be possible to incorporate NMR-active isotopes in the C-terminal part selectively. Extensive biochemical work established successful expressed protein ligation for two separate ligation joints in ?1AT and provided proof-of-concept for the strategy. The polymerization of ?1AT can happen trough the insertion of the C-terminal tail into the succeeding molecule and features of this mechanism were investigated through a series of interaction experiments. Despite a very buried location in the native structure, evidence here suggest that the C-terminal tail is labile under slightly destabilizing conditions, providing new detail to this matter. A small infectious polymer unit was also constructed and used to show how polymerogenic seeding and polymer propagation might happen inside the body. The locking of central structural elements during ?1AT folding or in the native state represents a therapeutic strategy to prevent polymerization. Using Molecular Dynamics simulations, we identified a new druggable pocket on the surface of ?1AT that could be targeted to serve this purpose. The proteolytically generated C-terminal tail from ?1AT is 36 residues long (C- 36) and is present in various bodily fluids. The peptide is able to form amyloid fibrils and we provide the first characterization of the fibrillation mechanism and of the amyloid structures that arise. The fibrillation is greatly enhanced by the presence of the anionic heparin sugar chain and we establish a model to describe these effects. Such negatively charged sugar molecules are ubiquitously associated with amyloid deposits in vivo, underlining the importance of understanding this relationship. The monomeric C-36 peptide was investigated by liquid-state NMR spectroscopy and found to be intrinsically disordered with minor propensities towards ?-sheet structure. The plasticity of such a peptide makes it suitable for a whole range of interactions, including its conversion to the tightly packed repetitive ?-sheet arrangement of an amyloid fibre. The ultra-structural details of these fibres were established by electron microscopy and solid-state NMR was employed to resolve the underlying molecular structure. This last task has not been completed yet but solving such structures to atomic resolution is of high value for understanding and targeting the culprits of the amyloid-related conformational disorders. Lastly, this work also includes a study on the protease HtrA1 that localizes to certain amyloid plaques. We explore the mechanism behind its automaturation process and find it to depend on the integrity of a disulphide bond network

RisØr, Michael Wulff

2014-01-01

118

Serum Protein Profile Alterations in Hemodialysis Patients  

Energy Technology Data Exchange (ETDEWEB)

Background: Serum protein profiling patterns can reflect the pathological state of a patient and therefore may be useful for clinical diagnostics. Here, we present results from a pilot study of proteomic expression patterns in hemodialysis patients designed to evaluate the range of serum proteomic alterations in this population. Methods: Surface-Enhanced Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (SELDI-TOFMS) was used to analyze serum obtained from patients on periodic hemodialysis treatment and healthy controls. Serum samples from patients and controls were first fractionated into six eluants on a strong anion exchange column, followed by application to four array chemistries representing cation exchange, anion exchange, metal affinity and hydrophobic surfaces. A total of 144 SELDI-TOF-MS spectra were obtained from each serum sample. Results: The overall profiles of the patient and control samples were consistent and reproducible. However, 30 well-defined protein differences were observed; 15 proteins were elevated and 15 were decreased in patients compared to controls. Serum from one patient exhibited novel protein peaks suggesting possible additional changes due to a secondary disease process. Conclusion: SELDI-TOF-MS demonstrated dramatic serum protein profile differences between patients and controls. Similarity in protein profiles among dialysis patients suggests that patient physiological responses to end-stage renal disease and/or dialysis therapy have a major effect on serum protein profiles.

Murphy, G A; Davies, R W; Choi, M W; Perkins, J; Turteltaub, K W; McCutchen-Maloney, S L; Langlois, R G; Curzi, M P; Trebes, J E; Fitch, J P; Dalmasso, E A; Colston, B W; Ying, Y; Chromy, B A

2003-11-18

119

Serum amyloid A and inflammation in diabetic kidney disease and podocytes.  

Science.gov (United States)

Inflammatory pathways are central mechanisms in diabetic kidney disease (DKD). Serum amyloid A (SAA) is increased by chronic inflammation, but SAA has not been previously evaluated as a potential DKD mediator. The aims of this study were to determine whether SAA is increased in human DKD and corresponding mouse models and to assess effects of SAA on podocyte inflammatory responses. SAA was increased in the plasma of people with DKD characterized by overt proteinuria and inversely correlated with estimated glomerular filtration rate (creatinine-based CKD-EPI). SAA was also elevated in plasma of diabetic mouse models including type 1 diabetes (streptozotocin/C57BL/6) and type 2 diabetes (BTBR-ob/ob). SAA mRNA (Nephromine) was increased in human DKD compared with non-diabetic and/or glomerular disease controls (glomerular fold change 1.5, P=0.017; tubulointerstitium fold change 1.4, P=0.021). The kidneys of both diabetic mouse models also demonstrated increased SAA mRNA (quantitative real-time PCR) expression compared with non-diabetic controls (type 1 diabetes fold change 2.9; type 2 diabetes fold change 42.5, P=0.009; interaction by model P=0.57). Humans with DKD and the diabetic mouse models exhibited extensive SAA protein deposition in the glomeruli and tubulointerstitium in similar patterns by immunohistochemistry. SAA localized within podocytes of diabetic mice. Podocytes exposed to advanced glycation end products, metabolic mediators of inflammation in diabetes, increased expression of SAA mRNA (fold change 15.3, P=0.004) and protein (fold change 38.4, P=0.014). Podocytes exposed to exogenous SAA increased NF-?B activity, and pathway array analysis revealed upregulation of mRNA for NF-?B-dependent targets comprising numerous inflammatory mediators, including SAA itself (fold change 17.0, P=0.006). Inhibition of NF-?B reduced these pro-inflammatory responses. In conclusion, SAA is increased in the blood and produced in the kidneys of people with DKD and corresponding diabetic mouse models. Podocytes are likely to be key responder cells to SAA-induced inflammation in the diabetic kidney. SAA is a compelling candidate for DKD therapeutic and biomarker discovery. PMID:25531567

Anderberg, Robert J; Meek, Rick L; Hudkins, Kelly L; Cooney, Sheryl K; Alpers, Charles E; Leboeuf, Renee C; Tuttle, Katherine R

2015-03-01

120

Validación analítica de técnicas comerciales para la determinación de haptoglobina, proteína C reactiva y amiloide A sérico en caninos Analytical / validation of commercial assays for the determination of haptoglobin, C-reactive protein and serum amyloid A in dogs  

Scientific Electronic Library Online (English)

Full Text Available Los métodos analíticos deben ser validados antes de emplearlos de forma rutinaria en un laboratorio. El objetivo de este trabajo fue validar tres métodos analíticos comerciales usados en nuestro laboratorio para la determinación de haptoglobina (Hp), proteína C reactiva (CRP) y amiloide A sérico (SA [...] A) en muestras de la especie canina con concentraciones bajas y altas de proteínas de fase aguda (PFAs). Los parámetros que se evaluaron para la validación fueron: (1) Precisión, determinada mediante el cálculo de los coeficientes de variación (CVs) intra e interdeterminación. (2) Exactitud, evaluada indirectamente comprobando la linealidad bajo dilución. (3) Límite de detección, determinado como la mínima concentración que puede distinguirse de una muestra de valor 0. Todos los CVs intradeterminación fueron Abstract in english All laboratory tests must be validated before being introduced for patient testing. The objective of this work was to perform the analytical validation of three commercial assays that are being used at our laboratory for the determination of haptoglobin (Hp), C reactive protein (CRP) and serum amylo [...] id A (SAA) in canine samples with low and high concentrations of these acute phase proteins (APPs). The parameters evaluated for the validation of the methods were: (1) Precision, assessed by determination of the within and between-run coefficients of variation (CVs). (2) Inaccuracy, evaluated indirectly by investigating linearity under dilution. (3) Limit of detection, determined as the lowest concentration of the APPs which could be distinguished from a zero sample. All within-run CVs were lower than 10%, however between-run CVs were lower than 10% only for Hp. Dilution of a serum sample with high concentrations of the different APPs resulted in a linear regression equation with correlation coefficient R²0.98 in all cases; so all methods showed a good accuracy. The detection limit of each assay was 0.02 g/L for Hp, 0.15 mg/L for CRP and 0.79 mg/L for SAA. Additionally they differentiate animals with inflammatory or infectious diseases from healthy subjects. Overall results of validation showed that the assays tested can be suitable for the routine measurement of APPs in canine samples, although it would be desirable to reduce the between run imprecision found for CRP and SAA assays.

S., Martínez-Subiela; J. J., Cerón.

121

AMPA receptor activation promotes non-amyloidogenic amyloid precursor protein processing and suppresses neuronal amyloid-? production.  

Science.gov (United States)

Soluble oligomeric amyloid ? peptide (A?) generated from processing of the amyloid precursor protein (APP) plays a central role in the pathogenesis of Alzheimer's Disease (AD) and through actions at glutamatergic synapses affects excitability and plasticity. The physiological control of APP processing is not fully understood but stimulation of synaptic NMDA receptors (NMDAR) can suppress A? levels through an ERK-dependent increase in ?-secretase activity. AMPA-type glutamate receptors (AMPAR) couple to ERK phosphorylation independently of NMDAR activation raising the possibility that stimulation of AMPAR might similarly promote non-amyloidogenic APP processing. We have tested this hypothesis by investigating whether AMPAR directly regulate APP processing in cultured mouse cortical neurons, by analyzing APP C-terminal fragments (CTFs), soluble APP (sAPP), A? levels, and cleavage of an APP-GAL4 reporter protein. We report that direct stimulation of AMPAR increases non-amyloidogenic ?-secretase-mediated APP processing and inhibits A? production. Processing was blocked by the matrix metalloproteinase inhibitor TAPI-1 but was only partially dependent on Ca(2+) influx and ERK activity. AMPAR can therefore, be added to the repertoire of receptors that couple to non-amyloidogenic APP processing at glutamatergic synapses and thus pharmacological targeting of AMPAR could potentially influence the development and progression of A? pathology in AD. PMID:24205136

Hoey, Sarah E; Buonocore, Federica; Cox, Carla J; Hammond, Victoria J; Perkinton, Michael S; Williams, Robert J

2013-01-01

122

The Acyl-Coenzyme A:Cholesterol Acyltransferase Inhibitor CI-1011 Reverses Diffuse Brain Amyloid Pathology in Aged Amyloid Precursor Protein Transgenic Mice  

OpenAIRE

Cerebral accumulation of amyloid ?-peptide (A?) is characteristic of Alzheimer disease and of amyloid precursor protein (APP) transgenic mice. Here, we assessed the efficacy of CI-1011, an inhibitor of acyl-coenzyme A:cholesterol acyltransferase, which is suitable for clinical use, in reducing amyloid pathology in both young (6.5 months old) and aged (16 months old) hAPP transgenic mice. Treatment of young animals with CI-1011 decreased amyloid plaque load in the cortex and hippocampus and ...

Huttunen, Henri J.; Havas, Daniel; Peach, Camilla; Barren, Cory; Duller, Stephan; Xia, Weiming; Frosch, Matthew P.; Hutter-paier, Birgit; Windisch, Manfred; Kovacs, Dora M.

2010-01-01

123

Elimination of the Class A Scavenger Receptor Does Not Affect Amyloid Plaque Formation or Neurodegeneration in Transgenic Mice Expressing Human Amyloid Protein Precursors  

OpenAIRE

The class A scavenger receptor (SR) is expressed on reactive microglia surrounding cerebral amyloid plaques in Alzheimer’s disease (AD). Interactions between the SR and amyloid ? peptides (A?) in microglial cultures elicit phagocytosis of A? aggregates and release of neurotoxins. To assess the role of the SR in amyloid clearance and A?-associated neurodegeneration in vivo, we used the platelet-derived growth factor promoter to express human amyloid protein precursors (hAPPs) in neurons ...

Huang, Frederick; Buttini, Manuel; Wyss-coray, Tony; Mcconlogue, Lisa; Kodama, Tatsuhiko; Pitas, Robert E.; Mucke, Lennart

1999-01-01

124

Amyloid Precursor Protein Binding Protein-1 Is Up-regulated in Brains of Tg2576 Mice  

OpenAIRE

Amyloid precursor protein binding protein-1 (APP-BP1) binds to the carboxyl terminus of amyloid precursor protein and serves as a bipartite activation enzyme for the ubiquitin-like protein, NEDD8. Previously, it has been reported that APP-BP1 rescues the cell cycle S-M checkpoint defect in Ts41 hamster cells, that this rescue is dependent on the interaction of APP-BP1 with hUba3. The exogenous expression of APP-BP1 in neurons has been reported to cause DNA synthesis and apoptosis via a signal...

Yang, Hyun Jung; Joo, Yuyoung; Hong, Bo-hyun; Ha, Sung-ji; Woo, Ran-sook; Lee, Sang Hyung; Suh, Yoo-hun; Kim, Hye-sun

2010-01-01

125

Amyloid Precursor Protein Binding Protein-1 Modulates Cell Cycle Progression in Fetal Neural Stem Cells  

OpenAIRE

Amyloid precursor protein binding protein-1 (APP-BP1) binds to the carboxyl terminus of the amyloid precursor protein (APP) and serves as the bipartite activation enzyme for the ubiquitin-like protein, NEDD8. In the present study, we explored the physiological role of APP-BP1 in the cell cycle progression of fetal neural stem cells. Our results show that cell cycle progression of the cells is arrested at the G1 phase by depletion of APP-BP1, which results in a marked decrease in the prolifera...

Joo, Yuyoung; Ha, Sungji; Hong, Bo-hyun; Kim, Jeong a; Chang, Keun-a; Liew, Hyunjeong; Kim, Seonghan; Sun, Woong; Kim, Joung-hun; Chong, Young Hae; Suh, Yoo-hun; Kim, Hye-sun

2010-01-01

126

Amyloid Protein and Neurofibrillary Tangles Coexist in the Same Neuron in Alzheimer Disease  

Science.gov (United States)

In Alzheimer disease, paired helical filaments accumulate in the neuron, and amyloid fibers are found in the extracellular space in the neuropil and brain vessels. Amyloid and paired helical filaments are morphologically distinct. Although messenger RNA that encodes the amyloid has also been shown in several tissues, including brain, the intracellular expression of the protein has not been observed. By using monoclonal antibodies to a synthetic amyloid ? peptide, the present study demonstrates that amyloid reactivity is present in both Alzheimer patients and normal individuals in different types of neurons, including the neurons with the neurofibrillary tangles, but not in the tangle itself.

Grundke-Iqbal, Inge; Iqbal, Khalid; George, Lalu; Tung, Yunn-Chyn; Kim, Kwang Soo; Wisniewski, Henry M.

1989-04-01

127

Protein misfolding, congophilia, oligomerization, and defective amyloid processing in preeclampsia.  

Science.gov (United States)

Preeclampsia is a pregnancy-specific disorder of unknown etiology and a leading contributor to maternal and perinatal morbidity and mortality worldwide. Because there is no cure other than delivery, preeclampsia is the leading cause of iatrogenic preterm birth. We show that preeclampsia shares pathophysiologic features with recognized protein misfolding disorders. These features include urine congophilia (affinity for the amyloidophilic dye Congo red), affinity for conformational state-dependent antibodies, and dysregulation of prototype proteolytic enzymes involved in amyloid precursor protein (APP) processing. Assessment of global protein misfolding load in pregnancy based on urine congophilia (Congo red dot test) carries diagnostic and prognostic potential for preeclampsia. We used conformational state-dependent antibodies to demonstrate the presence of generic supramolecular assemblies (prefibrillar oligomers and annular protofibrils), which vary in quantitative and qualitative representation with preeclampsia severity. In the first attempt to characterize the preeclampsia misfoldome, we report that the urine congophilic material includes proteoforms of ceruloplasmin, immunoglobulin free light chains, SERPINA1, albumin, interferon-inducible protein 6-16, and Alzheimer's ?-amyloid. The human placenta abundantly expresses APP along with prototype APP-processing enzymes, of which the ?-secretase ADAM10, the ?-secretases BACE1 and BACE2, and the ?-secretase presenilin-1 were all up-regulated in preeclampsia. The presence of ?-amyloid aggregates in placentas of women with preeclampsia and fetal growth restriction further supports the notion that this condition should join the growing list of protein conformational disorders. If these aggregates play a pathophysiologic role, our findings may lead to treatment for preeclampsia. PMID:25031267

Buhimschi, Irina A; Nayeri, Unzila A; Zhao, Guomao; Shook, Lydia L; Pensalfini, Anna; Funai, Edmund F; Bernstein, Ira M; Glabe, Charles G; Buhimschi, Catalin S

2014-07-16

128

Carboxyl-terminal fragments of beta-amyloid precursor protein bind to microtubules and the associated protein tau.  

OpenAIRE

Alzheimer's disease is a neurodegenerative disorder characterized by protein depositions in intracellular and extracellular spaces in the brain. The intraneuronal deposits are formed by neurofibrillary tangles composed mainly of abnormally phosphorylated tau, a microtubule-associated protein, whereas the major constituent of the amyloid deposited extracellularly in the brain parenchyma and vessel walls is amyloid beta-protein (A beta). The proteolytic processing of the beta-amyloid precursor ...

Islam, K.; Levy, E.

1997-01-01

129

The Role of Amyloid Precursor Protein Processing by BACE1, the ?-Secretase, in Alzheimer Disease Pathophysiology*  

OpenAIRE

Amyloid plaques, composed of the amyloid ?-protein (A?), are hallmark neuropathological lesions in Alzheimer disease (AD) brain. A? fulfills a central role in AD pathogenesis, and reduction of A? levels should prove beneficial for AD treatment. A? generation is initiated by proteolysis of amyloid precursor protein (APP) by the ?-secretase enzyme BACE1. Bace1 knockout (Bace1–/–) mice have validated BACE1 as the authentic ?-secretase in vivo. BACE1 is esse...

Cole, Sarah L.; Vassar, Robert

2008-01-01

130

Zinc Inhibits Amyloid ? Production from Alzheimer's Amyloid Precursor Protein in SH-SY5Y Cells  

Science.gov (United States)

Zinc released from excited glutamatergic neurons accelerates amyloid ? (A?) aggregation, underscoring the therapeutic potential of zinc chelation for the treatment of Alzheimer's disease (AD). Zinc can also alter A? concentration by affecting its degradation. In order to elucidate the possible role of zinc influx in secretase-processed A? production, SH-SY5Y cells stably expressing amyloid precursor protein (APP) were treated with pyrrolidine dithiocarbamate (PDTC), a zinc ionophore, and the resultant changes in APP processing were examined. PDTC decreased A?40 and A?42 concentrations in culture media bathing APP-expressing SH-SY5Y cells. Measuring the levels of a series of C-terminal APP fragments generated by enzymatic cutting at different APP-cleavage sites showed that both ?- and ?-cleavage of APP were inhibited by zinc influx. PDTC also interfered with the maturation of APP. PDTC, however, paradoxically increased the intracellular levels of A?40. These results indicate that inhibition of secretase-mediated APP cleavage accounts -at least in part- for zinc inhibition of A? secretion. PMID:19885037

Lee, Jinu; Kim, Chul Hoon; Kim, Dong Goo

2009-01-01

131

Serum proteins analysis by capillary electrophoresis  

OpenAIRE

The purpose of this study was to evaluate the efficacy of multi-capillary electrophoresis instrument in clinical laboratory. An automated clinical capillary electrophoresis system was evaluated for performing serum proteins electrophoresis and immuno-fixation electrophoresis by subtraction. In this study the performance of capillary electrophoresis was compared with the cellulose acetate membrane electrophoresis and agarose gel immunofixation electrophoresis for serum proteins. The results of...

Uji, Yoshinori; Okabe, Hiroaki

2001-01-01

132

Analysis of Amyloid beta (Ab) protein in Amyloid precursor protein (APP) transgenic mouse models of Alzheimer’s disease (AD) and in human brains  

OpenAIRE

Soluble amyloid b-protein (Ab) aggregates have been identified in Alzheimer"s disease (AD) brain. To address the roles of soluble and dispersible Ab aggregates for neurodegeneration we analyzed two different amyloid precursor protein (APP)-transgenic mouse models. APP23 mice overexpress human mutant APP with the Swedish mutation. APP51/16 mice express high levels of human wild-type APP. Both mice develop Ab plaques. Dendritic degeneration, neuron loss, and loss of asymmetric synapses were see...

Rijal Upadhaya, Ajeet

2012-01-01

133

The amyloid precursor protein intracellular domain-fe65 multiprotein complexes: a challenge to the amyloid hypothesis for Alzheimer's disease?  

Science.gov (United States)

Since its proposal in 1994, the amyloid cascade hypothesis has prevailed as the mainstream research subject on the molecular mechanisms leading to the Alzheimer's disease (AD). Most of the field had been historically based on the role of the different forms of aggregation of ?-amyloid peptide (A?). However, a soluble intracellular fragment termed amyloid precursor protein (APP) intracellular domain (AICD) is produced in conjunction with A? fragments. This peptide had been shown to be highly toxic in both culture neurons and transgenic mice models. With the advent of this new toxic fragment, the centerpiece for the ethiology of the disease may be changed. This paper discusses the potential role of multiprotein complexes between the AICD and its adapter protein Fe65 and how this could be a potentially important new agent in the neurodegeneration observed in the AD. PMID:22506131

Bórquez, Daniel A; González-Billault, Christian

2012-01-01

134

The human ?-amyloid precursor protein: biomolecular and epigenetic aspects.  

Science.gov (United States)

Abstract Beta-amyloid precursor protein (APP) is a membrane-spanning protein with a large extracellular domain and a much smaller intracellular domain. APP plays a central role in Alzheimer's disease (AD) pathogenesis: APP processing generates ?-amyloid (A?) peptides, which are deposited as amyloid plaques in the brains of AD individuals; point mutations and duplications of APP are causal for a subset of early-onset familial AD (FAD) (onset age 65 years old), and the pathophysiology of this disorder is not yet fully understood. APP is an extremely complex molecule that may be functionally important in its full-length configuration, as well as the source of numerous fragments with varying effects on neural function, yet the normal function of APP remains largely unknown. This article provides an overview of our current understanding of APP, including its structure, expression patterns, proteolytic processing and putative functions. Importantly, and for the first time, my recent data concerning its epigenetic regulation, especially in alternative APP pre-mRNA splicing and in the control of genomic rearrangements of the APP gene, are also reported. These findings may provide new directions for investigating the role of APP in neuropathology associated with a deficiency in the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGprt) found in patients with Lesch-Nyhan syndrome (LNS) and its attenuated variants (LNVs). Also, these findings may be of significance for research in neurodevelopmental and neurodegenerative disorders in which the APP gene is involved in the pathogenesis of diseases such as autism, fragile X syndrome (FXS) and AD, with its diversity and complexity, SAD in particular. Accurate quantification of various APP-mRNA isoforms in brain tissues is needed, and antisense drugs are potential treatments. PMID:25719338

Nguyen, Khue Vu

2015-03-01

135

Herpes simplex virus interferes with amyloid precursor protein processing  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The early events underlying Alzheimer's disease (AD remain uncertain, although environmental factors may be involved. Work in this laboratory has shown that the combination of herpes simplex virus type 1 (HSV1 in brain and carriage of the APOE-?4 allele of the APOE gene strongly increases the risk of developing AD. The development of AD is thought to involve abnormal aggregation or deposition of a 39–43 amino acid protein – ? amyloid (A? – within the brain. This is cleaved from the much larger transmembranal protein 'amyloid precursor protein' (APP. Any agent able to interfere directly with A? or APP metabolism may therefore have the capacity to contribute towards AD. One recent report showed that certain HSV1 glycoprotein peptides may aggregate like A?; a second study described a role for APP in transport of virus in squid axons. However to date the effects of acute herpesvirus infection on metabolism of APP in human neuronal-type cells have not been investigated. In order to find if HSV1 directly affects APP and its degradation, we have examined this protein from human neuroblastoma cells (normal and transfected with APP 695 infected with the virus, using Western blotting. Results We have found that acute HSV1 (and also HSV2 infection rapidly reduces full length APP levels – as might be expected – yet surprisingly markedly increases levels of a novel C-terminal fragment of APP of about 55 kDa. This band was not increased in cells treated with the protein synthesis inhibitor cycloheximide Conclusion Herpes virus infection leads to rapid loss of full length APP from cells, yet also causes increased levels of a novel 55 kDa C-terminal APP fragment. These data suggest that infection can directly alter the processing of a transmembranal protein intimately linked to the aetiology of AD.

Itzhaki Ruth F

2005-08-01

136

A Drosophila gene encoding a protein resembling the human. beta. -amyloid protein precursor  

Energy Technology Data Exchange (ETDEWEB)

The authors have isolated genomic and cDNA clones for a Drosophila gene resembling the human {beta}-amyloid precursor protein (APP). This gene produces a nervous system-enriched 6.5-kilobase transcript. Sequencing of cDNAs derived from the 6.5-kilobase transcript predicts an 886-amino acid polypeptide. This polypeptide contains a putative transmembrane domain and exhibits strong sequence similarity to cytoplasmic and extracellular regions of the human {beta}-amyloid precursor protein. There is a high probability that this Drosophila gene corresponds to the essential Drosophila locus vnd, a gene required for embryonic nervous system development.

Rosen, D.R.; Martin-Morris, L.; Luo, L.; White, K. (Brandeis Univ., Waltham, MA (USA))

1989-04-01

137

Amyloid Precursor Protein (APP) Mediated Regulation of Ganglioside Homeostasis Linking Alzheimer's Disease Pathology with Ganglioside Metabolism  

OpenAIRE

Gangliosides are important players for controlling neuronal function and are directly involved in AD pathology. They are among the most potent stimulators of A? production, are enriched in amyloid plaques and bind amyloid beta (A?). However, the molecular mechanisms linking gangliosides with AD are unknown. Here we identified the previously unknown function of the amyloid precursor protein (APP), specifically its cleavage products A? and the APP intracellular domain (AICD), of regulating G...

Grimm, Marcus O. W.; Zinser, Eva G.; Gro?sgen, Sven; Hundsdo?rfer, Benjamin; Rothhaar, Tatjana L.; Burg, Verena K.; Kaestner, Lars; Bayer, Thomas A.; Lipp, Peter; Mu?ller, Ulrike; Grimm, Heike S.; Hartmann, Tobias

2012-01-01

138

Increased serum amyloid A and its association with autoantibodies, acute phase reactants and disease activity in patients with rheumatoid arthritis.  

Science.gov (United States)

Determination of disease activity in patients with rheumatoid arthritis (RA) has become an important component for RA management. The aim of the present study was to investigate the association between circulating levels of serum amyloid A (SAA) and disease activity in RA patients. The types of disease and the respective number of patients enrolled in the present study were as follows: RA, 88; osteoarthritis (OA), 54; systemic lupus erythematosus (SLE), 43; and other autoimmune diseases, 30, as well as 50 healthy controls (HC). SAA levels were measured using an ELISA assay and western blot analysis was used to detect serum SAA levels. The correlations between SAA levels and disease activity score for 28 joints (DAS28), erythrocyte sedimentation rate (ESR) and C?reactive protein (CRP), respectively, were evaluated; in addition, the presence and absence of rheumatoid factor (RF) and anti?cyclic citrullinated peptide antibody (anti?CCP) were detected in respect to SAA levels. The results of the present study demonstrated that serum levels of SAA in RA patients were significantly increased compared to those of the OA, SLE, others and HC patients (P<0.05). SAA levels were found to be positively correlated with DAS28, ESR and CRP levels (R2=0.6174, 0.4422 and 0.3919, respectively). In addition, anti?CCP was not correlated with DAS28 (R2=0.0154). Furthermore, increased SAA levels were detected in patients with positive anti?CCP compared with those in anti?CCP negative subjects (P<0.01). In conclusion, the results of the present study provided further evidence for possible roles of SAA in RA, which indicated that it may be a useful biomarker for assessing disease severity and may provide additional information about disease activity. PMID:25352049

Shen, Chen; Sun, Xu-Guo; Liu, Na; Mu, Yun; Hong, Cheng-Cheng; Wei, Wei; Zheng, Fang

2015-02-01

139

The amyloid precursor protein and postnatal neurogenesis/neuroregeneration  

International Nuclear Information System (INIS)

The amyloid precursor protein (APP) is the source of amyloid-beta (A?) peptide, produced via its sequential cleavage ?- and ?-secretases. Various biophysical forms of A? (and the mutations of APP which results in their elevated levels) have been implicated in the etiology and early onset of Alzheimer's disease. APP's evolutionary conservation and the existence of APP-like isoforms (APLP1 and APLP2) which lack the A? sequence, however, suggest that these might have important physiological functions that are unrelated to A? production. Soluble N-terminal fragments of APP have been known to be neuroprotective, and the interaction of its cytoplasmic C-terminus with a myriad of proteins associates it with diverse processes such as axonal transport and transcriptional regulation. The notion for an essential postnatal function of APP has been demonstrated genetically, as mice deficient in both APP and APLP2 or all three APP isoforms exhibit early postnatal lethality and neuroanatomical abnormalities. Recent findings have also brought to light two possible functions of the APP family in Brain-regulation of neural progenitor cell proliferation and axonal outgrowth after injury. Interestingly, these two apparently related neurogenic/neuroregenerative functions of APP involve two separate domains of the molecule

140

LINGO-1 promotes lysosomal degradation of amyloid-? protein precursor  

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Full Text Available Sequential proteolytic cleavages of amyloid-? protein precursor (A?PP by ?-secretase and ?-secretase generate amyloid ? (A? peptides, which are thought to contribute to Alzheimer's disease (AD. Much of this processing occurs in endosomes following endocytosis of A?PP from the plasma membrane. However, this pathogenic mode of processing A?PP may occur in competition with lysosomal degradation of A?PP, a common fate of membrane proteins trafficking through the endosomal system. Following up on published reports that LINGO-1 binds and promotes the amyloidogenic processing of A?PP we have examined the consequences of LINGO-1/A?PP interactions. We report that LINGO-1 and its paralogs, LINGO-2 and LINGO-3, decrease processing of A?PP in the amyloidogenic pathway by promoting lysosomal degradation of A?PP. We also report that LINGO-1 levels are reduced in AD brain, representing a possible pathogenic mechanism stimulating the generation of A? peptides in AD.

Rian de Laat

2015-03-01

141

Cathepsin B degrades amyloid-? in mice expressing wild-type human amyloid precursor protein.  

Science.gov (United States)

Accumulation of amyloid-? (A?), believed to be a key trigger of Alzheimer disease (AD), could result from impaired clearance mechanisms. Previously, we showed that the cysteine protease cathepsin B (CatB) degrades A?, most likely by C-terminal truncation, in mice expressing human amyloid precursor protein with familial AD-linked mutations (hAPP(FAD)). In addition, the A?-degrading activity of CatB is inhibited by its endogenous inhibitor, cystatin C (CysC). Reducing CysC expression markedly lowers A? levels by enhancing CatB-mediated A? degradation in hAPP(FAD) mice. However, because a vast majority of AD patients do not carry familial mutations, we investigated how the CysC-CatB axis affects A? levels in mice expressing wild-type hAPP (hAPP(WT)). Enhancing CatB activity by CysC deletion significantly lowered total A? and A?42 levels in hAPP(WT) mice, whereas CatB deletion increased A? levels. To determine whether neuron-derived CatB degrades A? in vivo, we generated transgenic mice overexpressing CatB under the control of a neuron-specific enolase promoter. Enhancing neuronal CatB activity in hAPP(WT) mice significantly lowered A?42 levels. The processing of hAPP(WT) was unaffected by increasing or ablating CatB activity. Thus, the CysC-CatB axis affects degradation of A?42 derived from hAPP lacking familial mutations. These findings support the notion that enhancing CatB activity could lower A?, especially A?42, in AD patients with or without familial mutations. PMID:23024364

Wang, Chao; Sun, Binggui; Zhou, Yungui; Grubb, Anders; Gan, Li

2012-11-16

142

Selective ectodomain phosphorylation and regulated cleavage of beta-amyloid precursor protein.  

OpenAIRE

The beta-amyloid precursor protein (beta APP) is a highly conserved integral membrane protein expressed in most mammalian tissues and found at highest levels in the nervous system. Cerebral deposition of the amyloid beta-peptide (A beta), derived by proteolysis of beta APP, is an early and invariant feature of Alzheimer's disease. Protein phosphorylation by protein kinase C (PKC) has been found to regulate the metabolism of beta APP into nonamyloidogenic and amyloidogenic derivatives, but bot...

Hung, A. Y.; Selkoe, D. J.

1994-01-01

143

Synaptic NMDA receptor activation stimulates alpha-secretase amyloid precursor protein processing and inhibits amyloid-beta production  

OpenAIRE

Altered amyloid precursor protein (APP) processing leading to increased production and oligomerization of Abeta may contribute to Alzheimer's disease (AD). Understanding how APP processing is regulated under physiological conditions may provide new insights into AD pathogenesis. Recent reports demonstrate that excitatory neural activity regulates APP metabolism and Abeta levels, although understanding of the molecular mechanisms involved is incomplete. We have investigated whether NMDA recept...

Hoey, S. E.; Williams, R. J.; Perkinton, M. S.

2009-01-01

144

Cognitive phenotyping of amyloid precursor protein transgenic J20 mice.  

Science.gov (United States)

Transgenic mice that express familial Alzheimer's disease mutant forms of the human amyloid precursor protein (hAPP) have proved to be invaluable in determining the impact that the neurotoxic amyloid-? peptide has in vivo. In addition to the propensity to accumulate cerebral amyloid plaques, a crucial characteristic of hAPP mouse models is their cognitive impairments. To date the most widely used test for analyzing cognitive impairment in hAPP mice is the Morris water maze (MWM) which, due to the fact that mice are not "natural" swimmers, may not always be the ideal paradigm to investigate cognitive behaviours. Furthermore, not all cognitive impairments have been replicated across research laboratories. In the current study, we characterised the cognitive abilities of the J20 transgenic mouse line (expressing the Swedish 670/671(KM->NL) and Indiana (717(V->F)hAPP mutations) and non-transgenic mice. Mice were assessed in the cheeseboard task (i.e., a 'dry version' of the MWM) and a variety of other cognitive paradigms to test fear conditioning, object recognition and short-term memory to broaden the understanding of the cognitive deficits in J20 mice. hAPP transgenic mice perform normally in tasks for fear conditioning, short-term object recognition and short-term memory of context familiarity. However, they were profoundly impaired in their spatial reference memory capabilities in the cheeseboard task. The cheeseboard task has potential to replace the MWM task in situations where the MWM is not suitable for particular mouse models. PMID:22197298

Karl, Tim; Bhatia, Surabhi; Cheng, David; Kim, Woojin Scott; Garner, Brett

2012-03-17

145

Antibody-bound amyloid precursor protein upregulates ornithine decarboxylase expression  

DEFF Research Database (Denmark)

Alzheimer's disease is a neurodegenerative disorder characterised by extracellular accumulation of the Abeta peptide, derived from the amyloid precursor protein (APP). The function of APP as a cell surface receptor was examined by ligand-mimicking using an antibody against the APP extracellular domain. Alterations in gene expression evoked by antibody-bound APP were analysed using human pathway-finder gene arrays and the largest change in expression levels was found for ornithine decarboxylase (ODC). These results were confirmed by Western blotting which showed even higher upregulation on the protein level. APP knockdown by RNAi verified that upregulation of ODC was APP-mediated. This APP signalling event did not require gamma-secretase cleavage, as it was independent of the presence of presenilin-1 or -2. The induced ODC expression was rapid and biphasic, resembling growth-factor stimulated signalling events. This study shows that antibody-bound APP leads to altered gene expression that may be relevant to AD.

Nilsson, Tatjana; Malkiewicz, Katarzyna

2006-01-01

146

Pyrroloquinoline quinone inhibits the fibrillation of amyloid proteins  

OpenAIRE

Several neurodegenerative diseases involve the selective damage of neuron cells resulting from the accumulation of amyloid fibril formation. Considering that the formation of amyloid fibrils as well as their precursor oligomers is cytotoxic, the agents that prevent the formation of oligomers and/or fibrils might allow the development of a novel therapeutic approach to neurodegenerative diseases. Here, we show pyrroloquinoline quinone (PQQ) inhibits the amyloid fibril formation of the amyloid ...

Kim, Jihoon; Kobayashi, Masaki; Fukuda, Makoto; Ogasawara, Daisuke; Kobayashi, Natsuki; Han, Sungwoong; Nakamura, Chikashi; Inada, Masaki; Miyaura, Chisato; Ikebukuro, Kazunori; Sode, Koji

2010-01-01

147

Serum amyloid a gene expression and immunohistochemical localization in rainbow trout, Oncorhynchus mykiss, infected by Yersinia ruckeri  

DEFF Research Database (Denmark)

Serum amyloid A (SAA) is an integral part of the innate immune response in general and in particular the acute phase response. SAA belongs to a highly conserved group of apolipoproteins reported from different groups of organisms such as mammals, birds, fish and even invertebrates. The present study was undertaken to elucidate the role of SAA protein in the innate immune response of rainbow trout. For this purpose a monoclonal antibody was raised against a recombinant peptide of rainbow trout SAA. The antibody was characterized using Western blot, immunohistochemistry and ELISA techniques. SAA was found to be associated with high density lipoprotein (HDL) which complicated band identification in Western blot, but delipidization of the SAA-HDL isolate, using a solvent extraction method, highly increased the quality of reaction in the Western blot. Inhibition ELISA indicated the presence of SAA in serum and tissues (head kidney, liver and spleen) of rainbow trout. Rainbow trout fry (87 days post hatch) infected with Yersinia ruckeri showed a significant up-regulation of the SAA gene at 72 h post infection with further increase at 96 h post infection. Non-significant up-regulations were seen at earlier time points i.e. 4 and 24 h. A weak staining with the monoclonal antibody was seen at 4 h post infection which increased in intensity during the course of infection i.e. 24, 72 and 96 h post infection. The expression pattern of SAA in the infected fry, analysed by qPCR, significantly correlated with the results obtained by immunohistochemical methods. From the present study it can be concluded that the SAA may act as an acute phase protein in rainbow trout and its expression increases significantly during the course of infection.

Kania, Per Walter; Buchmann, Kurt

148

Neutron activation analysis of human serum proteins  

International Nuclear Information System (INIS)

Neutron activation analysis may be used to determine about 12 elements in serum samples. The blood has to be taken with a teflon cannula and processed in a dust-poor room. The pretreatment consists of lyophilisation or wet mineralisation. If necessary, post-irradiation separation is performed, based on adsorption on active carbon or hydride formation. The scope of the analysis is extended by gel permeation chromatography of the serum. The obtained fractions are then analyzed by instrumental neutron activation analysis. Alternatively, the combined proteins are separated from the ''salt'' fraction and analyzed. Results for normal human serum are given. (author)

149

Modulation of amyloid precursor protein processing by synthetic ceramide analogues.  

Science.gov (United States)

Previous studies suggest that membrane lipids may regulate proteolytic processing of the amyloid precursor protein (APP) to generate amyloid-beta peptide (Abeta). In the present study, we have assessed the capacity for a series of structurally related synthetic ceramide analogues to modulate APP processing in vitro. The compounds tested are established glucosylceramide synthase (GS) inhibitors based on the d-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP) structure. PDMP and related compounds PPMP and EtDO-P4 inhibited Abeta secretion from Chinese hamster ovary cells expressing human APP (CHO-APP) with approximate IC(50) values of 15, 5, and 1 microM, respectively. A trend for reduced secretion of the APP alpha-secretase product, sAPPalpha, was also observed in PDMP-treated cells but not in PPMP- or ETDO-P4-treated cells, whereas levels of the cellular beta-secretase product APP C-terminal fragment, CTFbeta, were increased by both PDMP and PPMP but unaltered with EtDO-P4 treatment. Our data also revealed that EtDO-P4 inhibits endogenous Abeta production by human neurons. In conclusion, this study provides novel information regarding the regulation of APP processing by synthetic ceramide analogues and reveals that the most potent of these compounds is EtDO-P4. PMID:20599631

Li, Hongyun; Kim, Woojin S; Guillemin, Gilles J; Hill, Andrew F; Evin, Genevieve; Garner, Brett

2010-08-01

150

Clinical correlation of serum protein electrophoresis  

International Nuclear Information System (INIS)

Serum protein electrophoresis is a simple, reliable and specific method of separating different protein fractious. A study was carried out in 1556 symptomatic cases reporting to Dept of Chemical pathology, Army Medical College of serum protein electrophoresis. Aims and objectives were to see the diagnostic significance of protein electrophoresis especially in comparison to other related investigations like serum protein estimation and albumin. globulin (A; G) ratio etc. Deluxe electrophoresis chamber and sample applicator was used. Gelman DCD-16 digital computing densitometer was used for quantification. Results revealed that protein electrophoresis was essential for diseases like paraproteinaemia. Immune deficiencies and aantitrypsin deficiency. It is helpful along with other investigations in liver disease, nephritic syndrome, collagen disease and malignancy. Three hundred and sixty five cases had subacute/chronic infection, 340 had normal electrophoretic pattern, 250 cases were of congestive cardiac failure, 152 cases of nephritic syndrome. 90 cases of hepatic cirrhosis, 53 cases of chronic renal failure and 25 cases of paraproteinaemia were identified. Its sensitivity and specificity was more than serum protein estimation by dye methods. It is recommended that, full use of this diagnostic technique should be made for better diagnostic sensitivity and specificity. (author)

151

Serum amyloid A induces calcium mobilization and chemotaxis of human monocytes by activating a pertussis toxin-sensitive signaling pathway.  

Science.gov (United States)

We have previously reported that serum amyloid A (SAA) induces adhesion and chemotaxis of human monocytes and polymorphonuclear neutrophils, in vitro as well as in vivo. Since the mechanism of SAA signaling is unknown, we have investigated the possibility that SAA, like other chemoattractants such as the chemotactic peptide FMLP and chemokines, might induce migration of monocytes by G protein activation. We report here that preincubation of monocytes with pertussis toxin (PTx) inhibited SAA chemotaxis, while incubation with cholera toxin (CTx) did not. Staurosporine and H-7, both inhibitors of protein kinase C (PKC), significantly decreased rSAA-induced chemotaxis of monocytes, suggesting that PKC may be involved in the rSAA signaling pathway. Moreover, rSAA, at concentrations that were effective in chemoattracting monocytes, resulted in transient elevation of cytoplasmic calcium concentration ([Ca2+]i), and incubation of cells with PTx markedly inhibited the mobilization of Ca2+ in response to rSAA. This suggests that both chemotaxis and the rise in [Ca2+]i, are mediated by G proteins of the Gi class. The increase in [Ca2+]i, induced in monocytes by rSAA, was comparable to that elicited by FMLP, and was severalfold greater than that induced by optimal concentrations of chemokine beta-family members such as RANTES, MCAF/MCP-1, and MIP-1 alpha. The chemoattractants FMLP, RANTES, MIP-1 alpha, and MCAF/MCP-1, all failed to desensitize rSAA-induced Ca2+ influx and chemotaxis in monocytes. This suggests that SAA uses a distinct receptor that is coupled to PTx-sensitive G proteins. PMID:7561109

Badolato, R; Johnston, J A; Wang, J M; McVicar, D; Xu, L L; Oppenheim, J J; Kelvin, D J

1995-10-15

152

Inhibition of dynamin-dependent endocytosis increases shedding of the amyloid precursor protein ectodomain and reduces generation of amyloid ? protein  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The amyloid precursor protein (APP is transported via the secretory pathway to the cell surface, where it may be cleaved within its ectodomain by ?-secretase, or internalized within clathrin-coated vesicles. An alternative proteolytic pathway occurs within the endocytic compartment, where the sequential action of ?- and ?-secretases generates the amyloid ? protein (A?. In this study, we investigated the effects of modulators of endocytosis on APP processing. Results Human embryonic kidney cells were transfected with a dominant negative mutant of dynamin I, an important mediator of clathrin-dependent endocytosis, and APP proteolysis was analyzed. Overexpression of the mutant dynamin (dyn I K44A resulted in increased shedding of the APP ectodomain (sAPP?, accumulation of the C-terminal ?-secretase product C83, and a reduction in the release of A?. Levels of mature APP on the cell surface were increased in cells expressing dyn I K44A, and internalization of surface-immunolabeled APP, assessed by fluorescence microscopy, was inhibited. Dynamin is a substrate for protein kinase C (PKC, and it was hypothesized that activators of PKC, which are known to stimulate ?-secretase-mediated cleavage of APP, might exert their effects by inhibiting dynamin-dependent endocytosis. However, the internalization of surface-biotinylated APP was unaffected by treatment of cells with phorbol 12-myristate 13-acetate in the presence of the ?-secretase inhibitor TAPI-1. Conclusion The results indicate that APP is internalized by a dynamin-dependent process, and suggest that alterations in the activity of proteins that mediate endocytosis might lead to significant changes in A? production.

Lopez-Coviella Ignacio

2005-08-01

153

Curcumin Reduces Amyloid Fibrillation of Prion Protein and Decreases Reactive Oxidative Stress  

OpenAIRE

Misfolding and aggregation into amyloids of the prion protein (PrP) is responsible for the development of fatal transmissible neurodegenerative diseases. Various studies on curcumin demonstrate promise for the prevention of Alzheimer’s disease and inhibition of PrPres accumulation. To evaluate the effect of curcumin on amyloid fibrillation of prion protein, we first investigated the effect of curcumin on mouse prion protein (mPrP) in a cell-free system. Curcumin reduced the prion fibril for...

Raymond Chung; Cheng-I Lee; Chi-Fen Lin; Cheng-Ping Jheng; Kun-Hua Yu

2013-01-01

154

Serum amyloid P component binds to influenza A virus haemagglutinin and inhibits the virus infection in vitro.  

DEFF Research Database (Denmark)

Serum amyloid P component (SAP) is a member of the phylogenetically conserved and structurally related group of proteins called pentraxins. SAP exhibits multispecific calcium-dependent binding to oligosaccharides with terminal N-acetyl-galactosamine, mannose and glucuronic acid. The authors report that SAP can bind to influenza A virus and inhibit agglutination of erythrocytes mediated by the virus subtypes H1N1, H2N2 and H3N2. SAP also inhibits the production of haemagglutinin (HA) an the cytopathogenic effect of influenza A virus in MDCK cells. The binding of SAP to the virus requires physiological calcium concentrations and is blocked by specific SAP antibodies. Denaturated and renaturated SAP retained inhibition of HA. Electron microscopy shows Ca(2+)-dependent binding of SAP to spikes on the viral envelope and immunoblotting indicates that SAP binds to a 50-55 kDa peptide corresponding to the mass of the HA1 peptide. Of several monosaccharides tested only D-mannose interfered with SAP's inhibition of both HA and infectivity. The glycosaminoglycans heparan sulfate and heparin, which bind SAP, reduced SAPs binding to the virus. The results indicate that the inhibition by SAP is due to steric effects when SAP binds to terminal mannose on oligosaccharides localized close to the sialic acid-binding site of the HA trimer.

Andersen, Ove; Vilsgaard Ravn, K

1997-01-01

155

Assessement of serum amyloid A levels in the rehabilitation setting in the Florida manatee (Trichechus manatus latirostris).  

Science.gov (United States)

The acute phase protein serum amyloid A (SAA) has been previously shown to have value as a biomarker of inflammation and infection in many species, including manatees (Trichechus manatus latirostris). In the current study, results from an automated assay for SAA were used in a rehabilitation setting. Reference intervals were established from clinically normal manatees using the robust method: 0-46 mg/L. More than 30-fold higher mean SAA levels were observed in manatees suffering from cold stress and boat-related trauma. Poor correlations were observed between SAA and total white blood count, percentage of neutrophils, albumin, and albumin/globulin ratio. A moderate correlation was observed between SAA and the presence of nucleated red blood cells. The sensitivity of SAA testing was 93% and the specificity was 98%, representing the highest combined values of all the analytes. The results indicate that the automated method for SAA quantitation can provide important clinical data for manatees in a rehabilitation setting. PMID:24450049

Cray, Carolyn; Dickey, Meranda; Brewer, Leah Brinson; Arheart, Kristopher L

2013-12-01

156

Altered cerebrospinal fluid levels of amyloid ? and amyloid precursor-like protein 1 peptides in Down's syndrome.  

Science.gov (United States)

Down's syndrome (DS) patients develop early Alzheimer's disease pathology with abundant cortical amyloid plaques, likely due to overproduction of the amyloid precursor protein (APP), which subsequently leads to amyloid ? (A?) aggregation. This is reflected in cerebrospinal fluid (CSF) levels of the 42-amino acid long A? peptide (A?1-42), which are increased in young DS patients and decreases with age. However, it is unclear whether DS also affects other aspects of A? metabolism, including production of shorter C- and N-terminal truncated A? peptides, and production of peptides from the amyloid precursor-like protein 1 (APLP1), which is related to APP, and cleaved by the same enzymatic processing machinery. APLP1-derived peptides may be surrogate markers for A?1-42 production in the brain. Here, we used hybrid immunoaffinity-mass spectrometry and enzyme-linked immunosorbent assays to monitor several A? and APLP1 peptides in CSF from DS patients (n = 12) and healthy controls (n = 20). CSF levels of A?1-42 and three endogenous peptides derived from APLP1 (APL1?25, APL1?27 and APL1?28) were decreased in DS compared with controls, while a specific A? peptide, A?1-28, was increased in a majority of the DS individuals. This study indicates that DS causes previously unknown specific alterations of APP and APLP1 metabolism. PMID:24740518

Portelius, Erik; Hölttä, Mikko; Soininen, Hilkka; Bjerke, Maria; Zetterberg, Henrik; Westerlund, Anni; Herukka, Sanna-Kaisa; Blennow, Kaj; Mattsson, Niklas

2014-06-01

157

Serum amyloid A opposes lipoxin A4 to mediate glucocorticoid refractory lung inflammation in chronic obstructive pulmonary disease  

OpenAIRE

Chronic obstructive pulmonary disease (COPD) will soon be the third most common cause of death globally. Despite smoking cessation, neutrophilic mucosal inflammation persistently damages the airways and fails to protect from recurrent infections. This maladaptive and excess inflammation is also refractory to glucocorticosteroids (GC). Here, we identify serum amyloid A (SAA) as a candidate mediator of GC refractory inflammation in COPD. Extrahepatic SAA was detected locally in COPD bronchoalve...

Bozinovski, Steven; Uddin, Mohib; Vlahos, Ross; Thompson, Michelle; Mcqualter, Jonathan L.; Merritt, Anne-sophie; Wark, Peter A. B.; Hutchinson, Anastasia; Irving, Louis B.; Levy, Bruce D.; Anderson, Gary P.

2012-01-01

158

FE65 Proteins Regulate NMDA Receptor Activation-induced Amyloid Precursor Protein Processing  

OpenAIRE

Amyloid precursor protein (APP) family members and their proteolytic products are implicated in normal nervous system function and Alzheimer’s disease pathogenesis. APP processing and A? secretion are regulated by neuronal activity. Various data suggest that NMDA receptor (NMDAR) activity plays a role in both non-amyloidogenic and amyloidogenic APP processing depending on whether synaptic or extrasynaptic NMDARs are activated, respectively. The APP-interacting FE65 proteins modulate APP tr...

Suh, Jaehong; Lyckman, Alvin; Wang, Lirong; Eckman, Elizabeth A.; Gue?nette, Suzanne Y.

2011-01-01

159

Organization and Biology of the Porcine Serum Amyloid A (SAA) Gene Cluster: Isoform Specific Responses to Bacterial Infection.  

DEFF Research Database (Denmark)

Serum amyloid A (SAA) is a prominent acute phase protein. Although its biological functions are debated, the wide species distribution of highly homologous SAA proteins and their uniform behavior in response to injury or inflammation in itself suggests a significant role for this protein. The pig is increasingly being used as a model for the study of inflammatory reactions, yet only little is known about how specific SAA genes are regulated in the pig during acute phase responses and other responses induced by pro-inflammatory host mediators. We designed SAA gene specific primers and quantified the gene expression of porcine SAA1, SAA2, SAA3, and SAA4 by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) in liver, spleen, and lung tissue from pigs experimentally infected with the Gram-negative swine specific bacterium Actinobacillus pleuropneumoniae, as well as from pigs experimentally infected with the Gram-positive bacterium Staphylococcus aureus. Our results show that: 1) SAA1 may be a pseudogene in pigs; 2) we were able to detect two previously uncharacterized SAA transcripts, namely SAA2 and SAA4, of which the SAA2 transcript is primarily induced in the liver during acute infection and presumably contributes to circulating SAA in pigs; 3) Porcine SAA3 transcription is induced both hepatically and extrahepatically during acute infection, and may be correlated to local organ affection; 4) Hepatic transcription of SAA4 is markedly induced in pigs infected with A. pleuropneumoniae, but only weakly in pigs infected with S. aureus. These results for the first time establish the infection response patterns of the four porcine SAA genes which will be of importance for the use of the pig as a model for human inflammatory responses, e.g. within sepsis, cancer, and obesity research.

Olsen, Helle G; Skovgaard, Kerstin

2013-01-01

160

Serum amyloid A chemoattracts immature dendritic cells and indirectly provokes monocyte chemotaxis by induction of cooperating CC and CXC chemokines.  

Science.gov (United States)

Serum amyloid A (SAA) is an acute phase protein that is upregulated in inflammatory diseases and chemoattracts monocytes, lymphocytes, and granulocytes via its G protein-coupled receptor formyl peptide receptor like 1/formyl peptide receptor 2 (FPRL1/FPR2). Here, we demonstrated that the SAA1? isoform also chemoattracts monocyte-derived immature dendritic cells (DCs) in the Boyden and ?-slide chemotaxis assay and that its chemotactic activity for monocytes and DCs was indirectly mediated via rapid chemokine induction. Indeed, SAA1 induced significant amounts (?5 ng/mL) of macrophage inflammatory protein-1?/CC chemokine ligand 3 (MIP-1?/CCL3) and interleukin-8/CXC chemokine ligand 8 (IL-8/CXCL8) in monocytes and DCs in a dose-dependent manner within 3 h. However, SAA1 also directly activated monocytes and DCs for signaling and chemotaxis without chemokine interference. SAA1-induced monocyte migration was nevertheless significantly prevented (60-80% inhibition) in the constant presence of desensitizing exogenous MIP-1?/CCL3, neutralizing anti-MIP-1?/CCL3 antibody, or a combination of CC chemokine receptor 1 (CCR1) and CCR5 antagonists, indicating that this endogenously produced CC chemokine was indirectly contributing to SAA1-mediated chemotaxis. Further, anti-IL-8/CXCL8 antibody neutralized SAA1-induced monocyte migration, suggesting that endogenous IL-8/CXCL8 acted in concert with MIP-1?/CCL3. This explained why SAA1 failed to synergize with exogenously added MIP-1?/CCL3 or stromal cell-derived factor-1? (SDF-1?)/CXCL12 in monocyte and DC chemotaxis. In addition to direct leukocyte activation, SAA1 induces a chemotactic cascade mediated by expression of cooperating chemokines to prolong leukocyte recruitment to the inflammatory site. PMID:25345597

Gouwy, Mieke; De Buck, Mieke; Pörtner, Noëmie; Opdenakker, Ghislain; Proost, Paul; Struyf, Sofie; Van Damme, Jo

2015-01-01

161

Protein ?-mediated effects on rat hippocampal choline transporters CHT1 and ?-amyloid ? interactions.  

Czech Academy of Sciences Publication Activity Database

Ro?. 38, ?. 9 (2013), s. 1949-1959. ISSN 0364-3190 Institutional support: RVO:67985882 Keywords : Tau protein * Amyloid ? peptide * Choline transporter Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 2.551, year: 2013

Krištofíková, Z.; ?ípová, D.; Hegnerová, Kate?ina; Šírová, J.; Homola, Ji?í

2013-01-01

162

B-Amyloid Precursor Protein Staining of the Brain in Sudden Infant and Early Childhood Death  

DEFF Research Database (Denmark)

To develop and validate a scoring method for assessing ?-amyloid precursor protein (APP) staining in cerebral white matter and to investigate the occurrence, amount and deposition pattern based on the cause of death in infants and young children.

Jensen, Lisbeth Lund; Banner, Jytte

2013-01-01

163

(PCG) Protein Crystal Growth Human Serum Albumin  

Science.gov (United States)

(PCG) Protein Crystal Growth Human Serum Albumin. Contributes to many transport and regulatory processes and has multifunctional binding properties which range from various metals, to fatty acids, hormones, and a wide spectrum of therapeutic drugs. The most abundant protein of the circulatory system. It binds and transports an incredible variety of biological and pharmaceutical ligands throughout the blood stream. Principal Investigator on STS-26 was Larry DeLucas.

1989-01-01

164

The role of protein hydrophobicity in conformation change and self-assembly into large amyloid fibers.  

Science.gov (United States)

It has been found that a short hydrophobic "template" peptide and a larger ?-helical "adder" protein cooperatively self-assemble into micrometer sized amyloid fibers. Here, a common template of trypsin hydrolyzed gliadin is combined with six adder proteins (?-casein, ?-lactalbumin, amylase, hemoglobin, insulin, and myoglobin) to determine what properties of the adder protein drive amyloid self-assembly. Utilizing Fourier Transform-Infrared (FT-IR) spectroscopy, the Amide I absorbance reveals that the observed decrease in ?-helix with time is approximately equal to the increase in high strand density ?-sheet, which is indicative of amyloid formation. The results show that the hydrophobic moment is a good predictor of conformation change but the fraction of aliphatic amino acids within the ?-helices is a better predictor. Upon drying, the protein mixtures form large amyloid fibers. The fiber twist is dependent on the aliphatic index and molecular weight of the adder protein. Here we demonstrate that it is possible to predict the propensity of an adder protein to unfold into an amyloid structure and to predict the fiber morphology, both from adder protein molecular features, which can be applied to the pragmatic engineering of large amyloid fibers. PMID:24601565

Ridgley, Devin M; Claunch, Elizabeth C; Lee, Parker W; Barone, Justin R

2014-04-14

165

The PreA4(695) precursor protein of Alzheimer's disease A4 amyloid is encoded by 16 exons.  

OpenAIRE

Alzheimer's disease (AD) is characterized by the cerebral deposition of fibrillar aggregates of the amyloid A4 protein. Complementary DNA's coding for the precursor of the amyloid A4 protein have been described. In order to identify the structure of the precursor gene relevant clones from several human genomic libraries were isolated. Sequence analysis of the various clones revealed 16 exons to encode the 695 residue precursor protein (PreA4(695] of Alzheimer's disease amyloid A4 protein. The...

Lemaire, H. G.; Salbaum, J. M.; Multhaup, G.; Kang, J.; Bayney, R. M.; Unterbeck, A.; Beyreuther, K.; Mu?ller-hill, B.

1989-01-01

166

Deciphering the Glycolipid Code of Alzheimer's and Parkinson's Amyloid Proteins Allowed the Creation of a Universal Ganglioside-Binding Peptide  

OpenAIRE

A broad range of microbial and amyloid proteins interact with cell surface glycolipids which behave as infectivity and/or toxicity cofactors in human pathologies. Here we have deciphered the biochemical code that determines the glycolipid-binding specificity of two major amyloid proteins, Alzheimer's ?-amyloid peptide (A?) and Parkinson's disease associated protein ?-synuclein. We showed that both proteins interact with selected glycolipids through a common loop-shaped motif exhibiting lit...

Yahi, Nouara; Fantini, Jacques

2014-01-01

167

Elevated levels of serum amyloid A indicate poor prognosis in patients with esophageal squamous cell carcinoma  

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Full Text Available Abstract Background Increase of Serum amyloid A (SAA level has been observed in patients with a variety of cancers. The objective of this study was to determined whether SAA level could be used as a prognostic parameter in patients with esophageal squamous cell carcinoma (ESCC. Methods SAA levels were measured by rate nephelometry immunoassay in 167 healthy controls and 167 ESCC patients prior to surgical resection. Statistical associations between clinicopathological observations and SAA levels were determined using the Mann–Whitney U test. The clinical value of SAA level as a prognostic parameter was evaluated using the Cox’s proportional hazards model. Results SAA levels were significantly higher in patients with ESCC compared to levels in healthy controls (13.88?±?15.19 mg/L vs. 2.26?±?1.66 mg/L, P?P?P?=?0.015, T classification (P?P?P?P?P? Conclusions An elevated level of preoperative SAA was found to associate with tumor progression and poor survival in patients with ESCC.

Wang Jun-Ye

2012-08-01

168

A brief elevation of serum amyloid A is sufficient to increase atherosclerosis.  

Science.gov (United States)

Serum amyloid A (SAA) has a number of proatherogenic effects including induction of vascular proteoglycans. Chronically elevated SAA was recently shown to increase atherosclerosis in mice. The purpose of this study was to determine whether a brief increase in SAA similarly increased atherosclerosis in a murine model. The recombination activating gene 1-deficient (rag1(-/-)) × apolipoprotein E-deficient (apoe(-/-)) and apoe(-/-) male mice were injected, multiple times or just once respectively, with an adenoviral vector encoding human SAA1 (ad-SAA); the injected mice and controls were maintained on chow for 12-16 weeks. Mice receiving multiple injections of ad-SAA, in which SAA elevation was sustained, had increased atherosclerosis compared with controls. Strikingly, mice receiving only a single injection of ad-SAA, in which SAA was only briefly elevated, also had increased atherosclerosis compared with controls. Using in vitro studies, we demonstrate that SAA treatment leads to increased LDL retention, and that prevention of transforming growth factor beta (TGF-?) signaling prevents SAA-induced increases in LDL retention and SAA-induced increases in vascular biglycan content. We propose that SAA increases atherosclerosis development via induction of TGF-?, increased vascular biglycan content, and increased LDL retention. These data suggest that even short-term inflammation with concomitant increase in SAA may increase the risk of developing CVD. PMID:25429103

Thompson, Joel C; Jayne, Colton; Thompson, Jennifer; Wilson, Patricia G; Yoder, Meghan H; Webb, Nancy; Tannock, Lisa R

2015-02-01

169

Serum amyloid P component inhibits influenza A virus infections: in vitro and in vivo studies.  

DEFF Research Database (Denmark)

Serum amyloid P component (SAP) binds in vitro Ca(2+)-dependently to several ligands including oligosaccharides with terminal mannose and galactose. We have earlier reported that SAP binds to human influenza A virus strains, inhibiting hemagglutinin (HA) activity and virus infectivity in vitro. These studies were extended to comprise five mouse-adapted influenza A strains, two swine influenza A strains, a mink influenza A virus, a ferret influenza A reassortant virus, a influenza B virus and a parainfluenza 3 virus. The HA activity of all these viruses was inhibited by SAP. Western blotting showed that SAP bound to HA trimers, monomers and HA1 and HA2 subunits of influenza A virus. Binding studies indicated that galactose, mannose and fucose moieties contributed to the SAP reacting site(s). Intranasal administration of human SAP to mice induced no demonstrable toxic reactions, and circulating antibodies against SAP were not detected. Preincubation of virus (A/Japan/57) with SAP prevented primary infection of mice and development of antiviral antibodies. After a single intranasal administration of SAP (40 microg) 1 h before primary infection with virus (2LD(50)), nine out of 10 mice survived on day 10 and these mice approached normal body weight, whereas control mice (one out of five surviving on day 10) died. The data provide evidence of the potential of intranasally administered SAP for prophylactic treatment of influenza A virus infections in humans.

Horvath, A; Andersen, I

2001-01-01

170

Stimulation of amyloid precursor protein synthesis by adrenergic receptors coupled to?cAMP?formation  

OpenAIRE

Amyloid plaques in Alzheimer disease are primarily aggregates of A? peptides that are derived from the amyloid precursor protein (APP). Neurotransmitter agonists that activate phosphatidylinositol hydrolysis and protein kinase C stimulate APP processing and generate soluble, non-amyloidogenic APP (APPs). Elevations in cAMP oppose this stimulatory effect and lead to the accumulation of cell-associated APP holoprotein containing amyloidogenic A? peptides. We now report that cAMP signaling can...

Lee, Robert K. K.; Araki, Wataru; Wurtman, Richard J.

1997-01-01

171

Palmitoylation of Amyloid Precursor Protein Regulates Amyloidogenic Processing in Lipid Rafts  

OpenAIRE

Brains of patients affected by Alzheimer's disease (AD) contain large deposits of aggregated amyloid ?-protein (A?). Only a small fraction of the amyloid precursor protein (APP) gives rise to A?. Here, we report that ?10% of APP undergoes a post-translational lipid modification called palmitoylation. We identified the palmitoylation sites in APP at Cys186 and Cys187. Surprisingly, point mutations introduced into these cysteines caused nearly complete ER retention of APP. Thus, either APP...

Bhattacharyya, Raja; Barren, Cory; Kovacs, Dora M.

2013-01-01

172

A positive correlation between serum amyloid ? levels and depressive symptoms among community-dwelling elderly individuals in Japan  

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Full Text Available Koji Tsuruga,1 Norio Sugawara,1 Norio Yasui-Furukori,1 Ippei Takahashi,2 Shoko Tsuchimine,1 Ayako Kaneda,1 Shigeyuki Nakaji,2 Kazuhiko Nakamura1 1Department of Neuropsychiatry, 2Department of Social Medicine, Hirosaki University School of Medicine, Hirosaki, Japan Background: Amyloid beta (A? levels have been associated with an increased risk of Alzheimer’s disease (AD. As depression is common before the onset of AD, serum Aß levels could be associated with depressive symptoms. The aim of this study was to investigate whether serum A? levels are associated with depressive symptoms and/or cognitive function in community-dwelling elderly individuals. Methods: We examined the association between serum A? levels and depression among 419 Japanese community-dwelling elderly individuals aged 60 years and over. Subjects were divided into two subgroups: younger elderly between 60 and 69 years old and older elderly over 69 years old. The Mini-Mental State Examination (MMSE was used to assess cognitive function, and symptoms of depression were assessed using the Center for Epidemiologic Studies Depression Scale (CES-D. The ability to perform activities of daily living was evaluated using the Tokyo Metropolitan Institute of Gerontology Index of Competence. Serum A? levels were measured with a human amyloid beta enzyme-linked immunosorbent assay kit. Results: After controlling for potential confounding variables, a multiple linear regression analysis showed that increased levels of serum A?40 and A?42 were associated with higher CES-D scores in the older elderly subgroup. Under the same condition, multiple regression showed that serum A? levels were not associated with MMSE scores among the total subjects, younger elderly, or older elderly. Conclusion: Serum A? levels were associated with depressive symptoms in community-dwelling elderly individuals. The present study indicates the possibility that serum A? may be involved in the development of late-onset depression. Keywords: Alzheimer’s disease, depression, dementia, Japanese

Tsuruga K

2014-08-01

173

Ribonuclease A suggests how proteins self-chaperone against amyloid fiber formation  

Energy Technology Data Exchange (ETDEWEB)

Genomic analyses have identified segments with high fiber-forming propensity in many proteins not known to form amyloid. Proteins are often protected from entering the amyloid state by molecular chaperones that permit them to fold in isolation from identical molecules; but, how do proteins self-chaperone their folding in the absence of chaperones? Here, we explore this question with the stable protein ribonuclease A (RNase A). We previously identified fiber-forming segments of amyloid-related proteins and demonstrated that insertion of these segments into the C-terminal hinge loop of nonfiber-forming RNase A can convert RNase A into the amyloid state through three-dimensional domain-swapping, where the inserted fiber-forming segments interact to create a steric zipper spine. In this study, we convert RNase A into amyloid-like fibers by increasing the loop length and hence conformational freedom of an endogenous fiber-forming segment, SSTSAASS, in the N-terminal hinge loop. This is accomplished by sandwiching SSTSAASS between inserted Gly residues. With these inserts, SSTSAASS is now able to form the steric zipper spine, allowing RNase A to form amyloid-like fibers. We show that these fibers contain RNase A molecules retaining their enzymatic activity and therefore native-like structure. Thus, RNase A appears to prevent fiber formation by limiting the conformational freedom of this fiber-forming segment from entering a steric zipper. Our observations suggest that proteins have evolved to self-chaperone by using similar protective mechanisms.

Teng, Poh K.; Anderson, Natalie J.; Goldschmidt, Lukasz; Sawaya, Michael R.; Sambashivan, Shilpa; Eisenberg, David (UCB)

2012-05-29

174

Intestinal Epithelial Serum Amyloid A Modulates Bacterial Growth In Vitro and Pro-Inflammatory Responses in Mouse Experimental Colitis  

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Full Text Available Abstract Background Serum Amyloid A (SAA is a major acute phase protein of unknown function. SAA is mostly expressed in the liver, but also in other tissues including the intestinal epithelium. SAA reportedly has anti-bacterial effects, and because inflammatory bowel diseases (IBD result from a breakdown in homeostatic interactions between intestinal epithelia and bacteria, we hypothesized that SAA is protective during experimental colitis. Methods Intestinal SAA expression was measured in mouse and human samples. Dextran sodium sulfate (DSS colitis was induced in SAA 1/2 double knockout (DKO mice and in wildtype controls. Anti-bacterial effects of SAA1/2 were tested in intestinal epithelial cell lines transduced with adenoviral vectors encoding the CE/J SAA isoform or control vectors prior to exposure to live Escherichia coli. Results Significant levels of SAA1/SAA2 RNA and SAA protein were detected by in situ hybridization and immunohistochemistry in mouse colonic epithelium. SAA3 expression was weaker, but similarly distributed. SAA1/2 RNA was present in the ileum and colon of conventional mice and in the colon of germfree mice. Expression of SAA3 was strongly regulated by bacterial lipopolysaccharides in cultured epithelial cell lines, whereas SAA1/2 expression was constitutive and not LPS inducible. Overexpression of SAA1/2 in cultured epithelial cell lines reduced the viability of co-cultured E. coli. This might partially explain the observed increase in susceptibility of DKO mice to DSS colitis. SAA1/2 expression was increased in colon samples obtained from Crohn's Disease patients compared to controls. Conclusions Intestinal epithelial SAA displays bactericidal properties in vitro and could play a protective role in experimental mouse colitis. Altered expression of SAA in intestinal biopsies from Crohn's Disease patients suggests that SAA is involved in the disease process..

Wang Yu

2010-11-01

175

Verification of measurement of the feline serum amyloid A (SAA) concentration by human SAA turbidimetric immunoassay and its clinical application.  

Science.gov (United States)

Serum amyloid A (SAA) is one of the major acute phase proteins in cats that has potential to be used as an inflammatory marker. A previous study showed that the human SAA turbidimetric immunoassay (hSAA-TIA) could be used to measure the SAA concentration in cats. The objectives of the present study were to assess use of hSAA-TIA for determining the feline SAA concentration and to evaluate its clinical application. Recombinant feline SAA protein (rfSAA) was expressed in Escherichia coli and purified for SDS-PAGE and immunoblot analysis with anti-human SAA antibodies. The concentration of rfSAA was determined by ELISA and hSAA-TIA. Plasma SAA concentrations were measured in healthy and diseased cats by hSAA-TIA. The time-courses changes in the SAA and alpha1-acid glycoprotein (AGP) concentrations in the cats after ovariohysterectomy were investigated. In SDS-PAGE, rfSAA was detected as a clear band that reacted with anti-human SAA antibodies. There was significant correlation between the SAA concentration measured by ELISA and hSAA-TIA. The SAA concentration of the diseased cats (n=263) was significantly increased (P<0.01; 0.0-88.9 mg/l, mean: 7.52 mg/l) compared with that in the healthy cats (n=26; 0.0-0.9 mg/l, mean: 0.14 mg/l). No correlation was observed between SAA and WBC in the diseased cats. The SAA concentration changed more rapidly and remarkably than the AGP concentration after ovariohysterectomy. The present study revealed that hSAA-TIA is useful for determination of the feline SAA concentration. Measurement of the SAA concentration, in addition to the WBC count, would be clinically valuable as a routine test to detect inflammation. PMID:19057145

Tamamoto, Takashi; Ohno, Koichi; Ohmi, Aki; Goto-Koshino, Yuko; Tsujimoto, Hajime

2008-11-01

176

Protein Interactions between Fe65, the LDL receptor-related protein and the amyloid precursor protein  

Science.gov (United States)

The adapter protein, Fe65 has been proposed to be the link between the intracellular domains of the amyloid precursor protein, APP (AICD) and the LDL receptor-related protein (LRP-CT). Functional linkage between these two proteins has been established and mutations within LRP-CT affect the amount of A? produced from APP. Previous work showed that the AICD binds to the protein interaction domain 2 (PID2) of Fe65. Although the structure of PID1 was solved recently all attempts to demonstrate LRP-CT binding to this domain failed. We used biophysical experiments and binding studies to investigate the binding between these three proteins. Full-length Fe65 bound more weakly to AICD than did N-terminally truncated forms, however the intramolecular domain-domain interactions that had been proposed to inhibit binding could not be observed using amide H/D exchange. Surprisingly, when the LRP-CT is phosphorylated at Tyr4507, it bound to Fe65-PID1 despite the fact that this domain belongs to the Dab-like subclass of PIDs that is not supposed to be phosphorylation dependent. Mutation of a critical arginine abolished binding providing further proof of the phosphorylation-dependence. The Fe65-PID1 domain thus provides a link between the Dab-like class and the IRS-like class of PID domains and is the first Dab-like family member to show phosphorylation-dependent binding. PMID:21650223

Mulvihill, Melinda; Guttman, Miklos; Komives, Elizabeth A.

2011-01-01

177

Protein Folding and Aggregation into Amyloid: The Interference by Natural Phenolic Compounds  

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Full Text Available Amyloid aggregation is a hallmark of several degenerative diseases affecting the brain or peripheral tissues, whose intermediates (oligomers, protofibrils and final mature fibrils display different toxicity. Consequently, compounds counteracting amyloid aggregation have been investigated for their ability (i to stabilize toxic amyloid precursors; (ii to prevent the growth of toxic oligomers or speed that of fibrils; (iii to inhibit fibril growth and deposition; (iv to disassemble preformed fibrils; and (v to favor amyloid clearance. Natural phenols, a wide panel of plant molecules, are one of the most actively investigated categories of potential amyloid inhibitors. They are considered responsible for the beneficial effects of several traditional diets being present in green tea, extra virgin olive oil, red wine, spices, berries and aromatic herbs. Accordingly, it has been proposed that some natural phenols could be exploited to prevent and to treat amyloid diseases, and recent studies have provided significant information on their ability to inhibit peptide/protein aggregation in various ways and to stimulate cell defenses, leading to identify shared or specific mechanisms. In the first part of this review, we will overview the significance and mechanisms of amyloid aggregation and aggregate toxicity; then, we will summarize the recent achievements on protection against amyloid diseases by many natural phenols.

Massimo Stefani

2013-06-01

178

Analysis of the acute phase responses of Serum Amyloid A, Haptoglobin and Type 1 Interferon in cattle experimentally infected with foot-and-mouth disease virus serotype O  

DEFF Research Database (Denmark)

A series of challenge experiments were performed in order to investigate the acute phase responses to foot-and-mouth disease virus (FMDV) infection in cattle and possible implications for the development of persistently infected "carriers". The host response to infection was investigated through measurements of the concentrations of the acute phase proteins (APPs) serum amyloid A (SAA) and haptoglobin (HP), as well as the bioactivity of type 1 interferon (IFN) in serum of infected animals. Results were based on measurements from a total of 36 infected animals of which 24 were kept for observational periods exceeding 28 days in order to determine the carrier-status of individual animals. The systemic host response to FMDV in infected animals was evaluated in comparison to similar measurements in sera from 6 mock-inoculated control animals.There was a significant increase in serum concentrations of both APPs and type 1 IFN in infected animals coinciding with the onset of viremia and clinical disease. The measured parameters declined to baseline levels within 21 days after inoculation, indicating that there was no systemically measurable inflammatory reaction related to the carrier state of FMD. There was a statistically significant difference in the HP response between carriers and non-carriers with a lower response in the animals that subsequently developed into FMDV carriers. It was concluded that the induction of SAA, HP and type 1 IFN in serum can be used as markers of acute infection by FMDV in cattle.

Stenfeldt, Carolina; Heegaard, Peter M. H.

2011-01-01

179

Liquid Crystalline Properties of Amyloid Protein Fibers in Water  

Science.gov (United States)

We have studied the liquid crystalline features of two colloidal systems consisting of food protein amyloid fibrils in water, obtained by heat-denaturation and aggregation of ?-lactoglobulin, a globular dairy protein. The resulting fibrils, have a monodisperse cross section of about 4 nm and two groups of polydisperse contour lengths: (i) fibrils 1-10 ?m long, showing semiflexible polyeletrolyte-like behaviour and (ii) rigid rods 100-200 nm long. In both systems, the fibers are highly charged (+5 e/nm) and stable in water at low ionic strength (0.01 M) and low pH (pH 2). The physical properties of these systems are studied using a polymer physics approach and phase diagrams of these two systems are obtained by changing concentration and pH. Both systems exhibit rich phase behaviours. Interestingly, the experimentally measured isotropic-nematic phase transition was found to occur at concentrations more than one order of magnitude lower than what expected based on Onsager theory. Experimental results are revisited in terms of the Flory theory developed for rigid polymers in solvent of varying conditions.

Mezzenga, Raffaele; Jung, Jin-Mi

2010-03-01

180

Regulatory region of human amyloid precursor protein (APP) gene promotes neuron-specific gene expression in the CNS of transgenic mice.  

OpenAIRE

The accumulation of beta-amyloid protein in specific brain regions is a central pathological feature of Alzheimer's disease (AD). The 4 kd beta-amyloid protein derives from a larger amyloid precursor protein (APP) by as yet unknown mechanisms. In the absence of a laboratory animal model of AD, transgenic mice expressing various APP gene products may provide new insights into the relationship between APP and beta-amyloid formation and the pathogenesis of AD. beta-amyloid accumulation in AD bra...

Wirak, D. O.; Bayney, R.; Kundel, C. A.; Lee, A.; Scangos, G. A.; Trapp, B. D.; Unterbeck, A. J.

1991-01-01

181

The metazoan protein disaggregase and amyloid depolymerase system: Hsp110, Hsp70, Hsp40, and small heat shock proteins.  

Science.gov (United States)

A baffling aspect of metazoan proteostasis is the lack of an Hsp104 ortholog that rapidly disaggregates and reactivates misfolded polypeptides trapped in stress induced disordered aggregates, preamyloid oligomers, or amyloid fibrils. By contrast, in bacteria, protozoa, chromista, fungi, and plants, Hsp104 orthologs are highly conserved and confer huge selective advantages in stress tolerance. Moreover, in fungi, the amyloid remodeling activity of Hsp104 has enabled deployment of prions for various beneficial modalities. Thus, a longstanding conundrum has remained unanswered: how do metazoan cells renature aggregated proteins or resolve amyloid fibrils without Hsp104? Here, we highlight recent advances that unveil the metazoan protein-disaggregase machinery, comprising Hsp110, Hsp70, and Hsp40, which synergize to dissolve disordered aggregates, but are unable to rapidly solubilize stable amyloid fibrils. However, Hsp110, Hsp70, and Hsp40 exploit the slow monomer exchange dynamics of amyloid, and can slowly depolymerize amyloid fibrils from their ends in a manner that is stimulated by small heat shock proteins. Upregulation of this system could have key therapeutic applications in various protein-misfolding disorders. Intriguingly, yeast Hsp104 can interface with metazoan Hsp110, Hsp70, and Hsp40 to rapidly eliminate disease associated amyloid. Thus, metazoan proteostasis is receptive to augmentation with exogenous disaggregases, which opens a number of therapeutic opportunities. PMID:24401655

Torrente, Mariana P; Shorter, James

2013-01-01

182

Serum Amyloid A and Clusterin as Potential Predictive Biomarkers for Severe Hand, Foot and Mouth Disease by 2D-DIGE Proteomics Analysis  

Science.gov (United States)

Hand, foot, and mouth disease (HFMD) affects more than one million children, is responsible for several hundred child deaths every year in China and is the cause of widespread concerns in society. Only a small fraction of HFMD cases will develop further into severe HFMD with neurologic complications. A timely and accurate diagnosis of severe HFMD is essential for assessing the risk of progression and planning the appropriate treatment. Human serum can reflect the physiological or pathological states, which is expected to be an excellent source of disease-specific biomarkers. In the present study, a comparative serological proteome analysis between severe HFMD patients and healthy controls was performed via a two-dimensional difference gel electrophoresis (2D-DIGE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) strategy. Fifteen proteins were identified as differentially expressed in the sera of the severe HFMD patients compared with the controls. The identified proteins were classified into different groups according to their molecular functions, biological processes, protein classes and physiological pathways by bioinformatics analysis. The up-regulations of two identified proteins, serum amyloid A (SAA) and clusterin (CLU), were confirmed in the sera of the HFMD patients by ELISA assay. This study not only increases our background knowledge about and scientific insight into the mechanisms of HFMD, but also reveals novel potential biomarkers for the clinical diagnosis of severe HFMD. PMID:25268271

Hong, Wen-Xu; Ren, Xiaohu; Yang, Xifei; He, Yanxia; Wang, Wenjian; Zhang, Renli; Yang, Hong; Zhao, Zhiguang; Huang, Haiyan; Chen, Long; Zhao, Dejian; Xian, Huixia; Yang, Fang; Ma, Dongli; Yang, Linqing; Yin, Yundong; Zhou, Li; Chen, Xiaozhen; Cheng, Jinquan

2014-01-01

183

Neuronal localization of amyloid beta protein precursor mRNA in normal human brain and in Alzheimer's disease.  

OpenAIRE

Clones for the amyloid beta protein precursor gene were isolated from a cDNA library prepared from the frontal cortex of a patient who had died with a histologically confirmed diagnosis of Alzheimer's disease; they were used to investigate the tissue and cellular distribution of amyloid beta protein precursor mRNA in brain tissues from control patients and from Alzheimer's disease patients. Amyloid beta protein precursor mRNA was expressed in similar amounts in all control human brain regions...

Goedert, M.

1987-01-01

184

Membrane-protein interactions hold the key to understanding amyloid formation  

CERN Document Server

In this perspective we describe the critical role membranes play in modulating the structures of the Amyloid Precursor Proteins to produce the peptides involved in the Alzheimer's disease. Some of the key concepts related to protein aggregation including the potential role of the excited states of monomers in initiating protein aggregation are described.

Straub, John E

2014-01-01

185

Modulation of Gene Expression and Cytoskeletal Dynamics by the Amyloid Precursor Protein Intracellular Domain (AICD)  

OpenAIRE

Amyloidogenic processing of the amyloid precursor protein (APP) results in the generation of ?-amyloid, the main constituent of Alzheimer plaques, and the APP intracellular domain (AICD). Recently, it has been demonstrated that AICD has transactivation potential; however, the targets of AICD-dependent gene regulation and hence the physiological role of AICD remain largely unknown. We analyzed transcriptome changes during AICD-dependent gene regulation by using a human neural cell culture sys...

Mu?ller, Thorsten; Concannon, Caoimhin G.; Ward, Manus W.; Walsh, Ciara M.; Tirniceriu, Anca L.; Tribl, Florian; Ko?gel, Donat; Prehn, Jochen H. M.; Egensperger, Rupert

2007-01-01

186

A study of b-secretase cleaved Alzheimer amyloid precursor protein  

OpenAIRE

Alzheimer's disease (AD) is characterized by the degeneration and loss of neurons, intracellular neurofibrillary tangles and the accumulation of extracellular senile plaques consisting mainly of beta- amyloid (A-beta). A-beta is generated from the amyloid precursor protein (APP) through sequential cleavage by proteases P- and gamma-secretase. Alternatively, APP may be cleaved within the A-beta region by alpha-secretase, preventing intact A-beta formation. Both the alpha- and...

Sennvik, Kristina

2002-01-01

187

Amyloidogenic processing of the Alzheimer ?-amyloid precursor protein depends on lipid rafts  

OpenAIRE

Formation of senile plaques containing the ?-amyloid peptide (A?) derived from the amyloid precursor protein (APP) is an invariant feature of Alzheimer's disease (AD). APP is cleaved either by ?-secretase or by ?-secretase to initiate amyloidogenic (release of A?) or nonamyloidogenic processing of APP, respectively. A key to understanding AD is to unravel how access of these enzymes to APP is regulated. Here, we demonstrate that lipid rafts are critically involved in regulating A? gener...

Ehehalt, Robert; Keller, Patrick; Haass, Christian; Thiele, Christoph; Simons, Kai

2003-01-01

188

Involvement of notch signaling pathway in amyloid precursor protein induced glial differentiation  

OpenAIRE

The amyloid precursor protein (APP) has been mainly studied in its role in the production of amyloid ? peptides (A?), because A? deposition is a hallmark of Alzheimer’s disease. Although several studies suggest APP has physiological functions, it is still controversial. We previously reported that APP increased glial differentiation of neural progenitor cells (NPCs). In the current study, NPCs transplanted into APP23 transgenic mice primarily differentiated into glial cells. In vitro tre...

Kwak, Young-don; Marutle, Amelia; Dantuma, Elise; Merchant, Stephanie; Bushnev, Sergey; Sugaya, Kiminobu

2010-01-01

189

Ectodomain shedding of the amyloid precursor protein: Cellular control mechanisms and novel modifiers  

OpenAIRE

Proteolytic cleavage in the ectodomain of the amyloid precursor protein (APP) is a key regulatory step in the generation of the Alzheimer's disease amyloid-beta (A beta) pepticle and occurs through two different protease activities termed alpha- and beta-secretase. Both proteases compete for APP cleavage, but have opposite effects on A beta generation. At present, little is known about the cellular pathways that control APP alpha- or beta-secretase cleavage and thus A beta generation. To expl...

Lichtenthaler, Stefan F.

2006-01-01

190

Idiopathic amyloidosis in the stone marten (Martes foina): identification of amyloid fibril proteins in tissue sections using the immunoperoxidase technique.  

Science.gov (United States)

Amyloid fibril proteins isolated from a spleen of a wild stone marten (Martes foina, Exleben) with idiopathic amyloidosis show resemblance to protein AA by amino acid analysis. An antiserum directed against these proteins can be used to identify the marten's amyloid in formalin-fixed tissue paraffin-embedded sections using the immunoperoxidase method. PMID:7004540

Linke, R P; Geisel, O; Eulitz, M; Nathrath, W B

1980-12-01

191

Oxysterol-binding protein-1 (OSBP1 modulates processing and trafficking of the amyloid precursor protein  

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Full Text Available Background Evidence from biochemical, epidemiological and genetic findings indicates that cholesterol levels are linked to amyloid-? (A? production and Alzheimer's disease (AD. Oxysterols, which are cholesterol-derived ligands of the liver X receptors (LXRs and oxysterol binding proteins, strongly regulate the processing of amyloid precursor protein (APP. Although LXRs have been studied extensively, little is known about the biology of oxysterol binding proteins. Oxysterol-binding protein 1 (OSBP1 is a member of a family of sterol-binding proteins with roles in lipid metabolism, regulation of secretory vesicle generation and signal transduction, and it is thought that these proteins may act as sterol sensors to control a variety of sterol-dependent cellular processes. Results We investigated whether OSBP1 was involved in regulating APP processing and found that overexpression of OSBP1 downregulated the amyloidogenic processing of APP, while OSBP1 knockdown had the opposite effect. In addition, we found that OSBP1 altered the trafficking of APP-Notch2 dimers by causing their accumulation in the Golgi, an effect that could be reversed by treating cells with OSBP1 ligand, 25-hydroxycholesterol. Conclusion These results suggest that OSBP1 could play a role in linking cholesterol metabolism with intracellular APP trafficking and A? production, and more importantly indicate that OSBP1 could provide an alternative target for A?-directed therapeutic.

Seabrook Guy R

2008-03-01

192

Purification and aggregation of the amyloid precursor protein intracellular domain.  

Science.gov (United States)

Amyloid precursor protein (APP) is a type I transmembrane protein associated with the pathogenesis of Alzheimer's disease (AD). APP is characterized by a large extracellular domain and a short cytosolic domain termed the APP intracellular domain (AICD). During maturation through the secretory pathway, APP can be cleaved by proteases termed ?, ?, and ?-secretases. Sequential proteolytic cleavage of APP with ? and ?-secretases leads to the production of a small proteolytic peptide, termed A?, which is amyloidogenic and the core constituent of senile plaques. The AICD is also liberated from the membrane after secretase processing, and through interactions with Fe65 and Tip60, can translocate to the nucleus to participate in transcription regulation of multiple target genes. Protein-protein interactions involving the AICD may affect trafficking, processing, and cellular functions of holo-APP and its C-terminal fragments. We have recently shown that AICD can aggregate in vitro, and this process is inhibited by the AD-implicated molecular chaperone ubiquilin-1. Consistent with these findings, the AICD has exposed hydrophobic domains and is intrinsically disordered in vitro, however it obtains stable secondary structure when bound to Fe65. We have proposed that ubiquilin-1 prevents inappropriate inter- and intramolecular interactions of AICD, preventing aggregation in vitro and in intact cells. While most studies focus on the role of APP in the pathogenesis of AD, the role of AICD in this process is not clear. Expression of AICD has been shown to induce apoptosis, to modulate signaling pathways, and to regulate calcium signaling. Over-expression of AICD and Fe65 in a transgenic mouse model induces Alzheimer's like pathology, and recently AICD has been detected in brain lysates by western blotting when using appropriate antigen retrieval techniques. To facilitate structural, biochemical, and biophysical studies of the AICD, we have developed a procedure to produce recombinantly large amounts of highly pure AICD protein. We further describe a method for inducing the in vitro thermal aggregation of AICD and analysis by atomic force microscopy. The methods described are useful for biochemical, biophysical, and structural characterization of the AICD and the effects of molecular chaperones on AICD aggregation. PMID:22952038

El Ayadi, Amina; Stieren, Emily S; Barral, José M; Oberhauser, Andres F; Boehning, Darren

2012-01-01

193

The Impairment of Macrophage-to-Feces Reverse Cholesterol Transport during Inflammation Does Not Depend on Serum Amyloid A  

OpenAIRE

Studies suggest that inflammation impairs reverse cholesterol transport (RCT). We investigated whether serum amyloid A (SAA) contributes to this impairment using an established macrophage-to-feces RCT model. Wild-type (WT) mice and mice deficient in SAA1.1 and SAA2.1 (SAAKO) were injected intraperitoneally with 3H-cholesterol-labeled J774 macrophages 4?hr after administration of LPS or buffered saline. 3H-cholesterol in plasma 4?hr after macrophage injection was significantly reduced in b...

Beer, Maria C.; Wroblewski, Joanne M.; Noffsinger, Victoria P.; Ailing Ji; Meyer, Jason M.; Westhuyzen, Deneys R.; Beer, Frederick C.; Webb, Nancy R.

2013-01-01

194

Serum amyloid A and pairing formyl peptide receptor 2 are expressed in corneas and involved in inflammation-mediated neovascularization  

OpenAIRE

AIM:To solidify the involvement of Saa-related pathway in corneal neovascularization (CorNV). The pathogenesis of inflammatory CorNV is not fully understood yet, and our previous study implicated that serum amyloid A (Saa) 1 (Saa1) and Saa3 were among the genes up-regulated upon CorNV induction in mice.METHODS:Microarray data obtained during our profiling project on CorNV were analyzed for the genes encoding the four SAA family members (Saa1-4), six reported SAA receptors (formyl peptide rece...

Sheng-Wei Ren; Xia Qi; Chang-Kai Jia; Yi-Qiang Wang

2014-01-01

195

Antibody microarray profiling reveals individual and combined serum proteins associated with pancreatic cancer.  

Science.gov (United States)

We used antibody microarrays to probe the associations of multiple serum proteins with pancreatic cancer and to explore the use of combined measurements for sample classification. Serum samples from pancreatic cancer patients (n = 61), patients with benign pancreatic disease (n = 31), and healthy control subjects (n = 50) were probed in replicate experiment sets by two-color, rolling circle amplification on microarrays containing 92 antibodies and control proteins. The antibodies that had reproducibly different binding levels between the patient classes revealed different types of alterations, reflecting inflammation (high C-reactive protein, alpha-1-antitrypsin, and serum amyloid A), immune response (high IgA), leakage of cell breakdown products (low plasma gelsolin), and possibly altered vitamin K usage or glucose regulation (high protein-induced vitamin K antagonist-II). The accuracy of the most significant antibody microarray measurements was confirmed through immunoblot and antigen dilution experiments. A logistic-regression algorithm distinguished the cancer samples from the healthy control samples with a 90% and 93% sensitivity and a 90% and 94% specificity in duplicate experiment sets. The cancer samples were distinguished from the benign disease samples with a 95% and 92% sensitivity and an 88% and 74% specificity in duplicate experiment sets. The classification accuracies were significantly improved over those achieved using individual antibodies. This study furthered the development of antibody microarrays for molecular profiling, provided insights into the nature of serum-protein alterations in pancreatic cancer patients, and showed the potential of combined measurements to improve sample classification accuracy. PMID:16322270

Orchekowski, Randal; Hamelinck, Darren; Li, Lin; Gliwa, Ewa; vanBrocklin, Matt; Marrero, Jorge A; Vande Woude, George F; Feng, Ziding; Brand, Randall; Haab, Brian B

2005-12-01

196

Adaptor protein sorting nexin 17 regulates amyloid precursor protein trafficking and processing in the early endosomes.  

Science.gov (United States)

Accumulation of extracellular amyloid beta peptide (Abeta), generated from amyloid precursor protein (APP) processing by beta- and gamma-secretases, is toxic to neurons and is central to the pathogenesis of Alzheimer disease. Production of Abeta from APP is greatly affected by the subcellular localization and trafficking of APP. Here we have identified a novel intracellular adaptor protein, sorting nexin 17 (SNX17), that binds specifically to the APP cytoplasmic domain via the YXNPXY motif that has been shown previously to bind several cell surface adaptors, including Fe65 and X11. Overexpression of a dominant-negative mutant of SNX17 and RNA interference knockdown of endogenous SNX17 expression both reduced steady-state levels of APP with a concomitant increase in Abeta production. RNA interference knockdown of SNX17 also decreased APP half-life, which led to the decreased steady-state levels of APP. Immunofluorescence staining confirmed a colocalization of SNX17 and APP in the early endosomes. We also showed that a cell surface adaptor protein, Dab2, binds to the same YXNPXY motif and regulates APP endocytosis at the cell surface. Our results thus provide strong evidence that both cell surface and intracellular adaptor proteins regulate APP endocytic trafficking and processing to Abeta. The identification of SNX17 as a novel APP intracellular adaptor protein highly expressed in neurons should facilitate the understanding of the relationship between APP intracellular trafficking and processing to Abeta. PMID:18276590

Lee, Jiyeon; Retamal, Claudio; Cuitiño, Loreto; Caruano-Yzermans, Amy; Shin, Jung-Eun; van Kerkhof, Peter; Marzolo, Maria-Paz; Bu, Guojun

2008-04-25

197

An Accessory Protein Required for Anchoring and Assembly of Amyloid Fibers in B. subtilis Biofilms  

OpenAIRE

Cells within Bacillus subtilis biofilms are held in place by an extracellular matrix that contains cell-anchored amyloid fibers, composed of the amyloidogenic protein TasA. As biofilms age they disassemble because the cells release the amyloid fibers. This release appears to be the consequence of incorporation of D-tyrosine, D-leucine, D-tryptophan and D-methionine into the cell wall. Here, we characterize the in vivo roles of an accessory protein TapA (TasA anchoring/assembly protein; previo...

Romero, Diego; Vlamakis, Hera; Losick, Richard; Kolter, Roberto

2011-01-01

198

Thyroid hormones regulate ?-amyloid gene splicing and protein secretion in neuroblastoma cells  

OpenAIRE

The ?-amyloid protein (A?), the major component of the senile plaques found in Alzheimer brains, derives from a larger ?-amyloid precursor protein (APP). Alternative splicing of the APP gene yields three major APP messenger RNAs (mRNAs), which, in turn, give rise to the APP770, APP751, and APP695 protein isoforms. In this study we examined the effects of thyroid hormone on APP expression in N2a-? neuroblastoma cells. T3 caused a significant increase in the APP770 mRNA band, in detriment o...

Latasa, Mari?a Jesu?s; Belandia, Borja; Pascual, A?ngel

1998-01-01

199

Self-assembling of amyloid-like proteins  

International Nuclear Information System (INIS)

Full text: Septins are proteins from the GTP-binding family and participate in cell division cycle performing functions such as secretion and cytoskeletal division. They can also be found in neurodegenerative conditions as Alzheimers and Parkinson's diseases, forming highly organized fiber-like aggregates known as amyloids. In this work, we used small angle x-ray scattering (SAXS) to investigate the formation and time evolution of septins aggregates under the influence of temperature and concentration. The SAXS measurements were performed with the GTPase domain of human Septin 2 (SEPT2G) at 0.5 and 1 mg/mL and temperatures between 4 and 45 deg C. At 0.5 mg/mL and 4 deg C, the protein self-aggregates as a dimer, being stable over one hour of observation. When the temperature was increased to 15 deg C, the results demonstrate that cylinder-like aggregates are formed and coexist with some dimer population and a small amount of larger aggregates. However, the number of very large aggregates increases with time concomitantly with the decrease of cylinder amount in the solution. At 37 deg C cylinder-like aggregates are not longer present in solution, whereas a significant amount of dimers decreases from 50% to 20% in less than 1 hour. At 45 deg C such an effect is even more accentuated: the percentage of dimers is only 6% in solution into a favor of 94% of very larger aggregates. When we analyze the protein at 1 mg/mL, at 4 deg C cylinder-like aggregates (36 nm-long and 12 nm-cross section) are already formed, coexisting with dimers and, as occurred for lower concentration, the two populations remained unchanged over one hour of observation. Out results also indicate that the dimensions of these cylinders increase with the concentration and the percentage of cylinders and larger aggregates are higher than those found for 0.5 mg/mL. In conclusion, our results showed the coexistence of dimers of SEPT2G with small fibers and larger aggregates in solution that evolve not only with concentration and temperature but also with time. (author)

200

Self-assembling of amyloid-like proteins  

Energy Technology Data Exchange (ETDEWEB)

Full text: Septins are proteins from the GTP-binding family and participate in cell division cycle performing functions such as secretion and cytoskeletal division. They can also be found in neurodegenerative conditions as Alzheimers and Parkinson's diseases, forming highly organized fiber-like aggregates known as amyloids. In this work, we used small angle x-ray scattering (SAXS) to investigate the formation and time evolution of septins aggregates under the influence of temperature and concentration. The SAXS measurements were performed with the GTPase domain of human Septin 2 (SEPT2G) at 0.5 and 1 mg/mL and temperatures between 4 and 45 deg C. At 0.5 mg/mL and 4 deg C, the protein self-aggregates as a dimer, being stable over one hour of observation. When the temperature was increased to 15 deg C, the results demonstrate that cylinder-like aggregates are formed and coexist with some dimer population and a small amount of larger aggregates. However, the number of very large aggregates increases with time concomitantly with the decrease of cylinder amount in the solution. At 37 deg C cylinder-like aggregates are not longer present in solution, whereas a significant amount of dimers decreases from 50% to 20% in less than 1 hour. At 45 deg C such an effect is even more accentuated: the percentage of dimers is only 6% in solution into a favor of 94% of very larger aggregates. When we analyze the protein at 1 mg/mL, at 4 deg C cylinder-like aggregates (36 nm-long and 12 nm-cross section) are already formed, coexisting with dimers and, as occurred for lower concentration, the two populations remained unchanged over one hour of observation. Out results also indicate that the dimensions of these cylinders increase with the concentration and the percentage of cylinders and larger aggregates are higher than those found for 0.5 mg/mL. In conclusion, our results showed the coexistence of dimers of SEPT2G with small fibers and larger aggregates in solution that evolve not only with concentration and temperature but also with time. (author)

Sales, E.M.; Barbosa, L.R.S.; Itri, R. [Universidade de Sao Paulo (USP), SP (Brazil); Damalio, J.C.P.; Araujo, A.P.U. [Universidade de Sao Paulo (USP-SC), Sao Carlos, SP (Brazil); Spinozzi, F.; Mariani, P. [Universita Politecnica delle Marche, Ancona (Italy)

2012-07-01

201

Novel role of RanBP9 in BACE1 processing of amyloid precursor protein and amyloid beta peptide generation.  

Science.gov (United States)

Accumulation of the amyloid beta (Abeta) peptide derived from the proteolytic processing of amyloid precursor protein (APP) is the defining pathological hallmark of Alzheimer disease. We previously demonstrated that the C-terminal 37 amino acids of lipoprotein receptor-related protein (LRP) robustly promoted Abeta generation independent of FE65 and specifically interacted with Ran-binding protein 9 (RanBP9). In this study we found that RanBP9 strongly increased BACE1 cleavage of APP and Abeta generation. This pro-amyloidogenic activity of RanBP9 did not depend on the KPI domain or the Swedish APP mutation. In cells expressing wild type APP, RanBP9 reduced cell surface APP and accelerated APP internalization, consistent with enhanced beta-secretase processing in the endocytic pathway. The N-terminal half of RanBP9 containing SPRY-LisH domains not only interacted with LRP but also with APP and BACE1. Overexpression of RanBP9 resulted in the enhancement of APP interactions with LRP and BACE1 and increased lipid raft association of APP. Importantly, knockdown of endogenous RanBP9 significantly reduced Abeta generation in Chinese hamster ovary cells and in primary neurons, demonstrating its physiological role in BACE1 cleavage of APP. These findings not only implicate RanBP9 as a novel and potent regulator of APP processing but also as a potential therapeutic target for Alzheimer disease. PMID:19251705

Lakshmana, Madepalli K; Yoon, Il-Sang; Chen, Eunice; Bianchi, Elizabetta; Koo, Edward H; Kang, David E

2009-05-01

202

Assessment of Oritavancin Serum Protein Binding across Species?  

OpenAIRE

Biophysical methods to study the binding of oritavancin, a lipoglycopeptide, to serum protein are confounded by nonspecific drug adsorption to labware surfaces. We assessed oritavancin binding to serum from mouse, rat, dog, and human by a microbiological growth-based method under conditions that allow near-quantitative drug recovery. Protein binding was similar across species, ranging from 81.9% in human serum to 87.1% in dog serum. These estimates support the translation of oritavancin expos...

Arhin, Francis F.; Belley, Adam; Mckay, Geoffrey; Beaulieu, Sylvain; Sarmiento, Ingrid; Parr, Thomas R.; Moeck, Gregory

2010-01-01

203

Amyloid precursor protein (APP) traffics from the cell surface via endosomes for amyloid ? (A?) production in the trans-Golgi network  

OpenAIRE

Amyloid precursor protein (APP) is processed sequentially by the ?-site APP cleaving enzyme and ?-secretase to generate amyloid ? (A?) peptides, one of the hallmarks of Alzheimer’s disease. The intracellular location of A? production—endosomes or the trans-Golgi network (TGN)—remains uncertain. We investigated the role of different postendocytic trafficking events in A?40 production using an RNAi approach. Depletion of Hrs and Tsg101, acting early in the multivesicular body pathwa...

Choy, Regina Wai-yan; Cheng, Zhiliang; Schekman, Randy

2012-01-01

204

Serum amyloid A and pairing formyl peptide receptor 2 are expressed in corneas and involved in inflammation-mediated neovascularization  

Directory of Open Access Journals (Sweden)

Full Text Available AIM:To solidify the involvement of Saa-related pathway in corneal neovascularization (CorNV. The pathogenesis of inflammatory CorNV is not fully understood yet, and our previous study implicated that serum amyloid A (Saa 1 (Saa1 and Saa3 were among the genes up-regulated upon CorNV induction in mice.METHODS:Microarray data obtained during our profiling project on CorNV were analyzed for the genes encoding the four SAA family members (Saa1-4, six reported SAA receptors (formyl peptide receptor 2, Tlr2, Tlr4, Cd36, Scarb1, P2rx7 and seven matrix metallopeptidases (Mmp 1a, 1b, 2, 3, 9, 10, 13 reportedly to be expressed upon SAA pathway activation. The baseline expression or changes of interested genes were further confirmed in animals with CorNV using molecular or histological methods. CorNV was induced in Balb/c and C57BL/6 mice by placing either three interrupted 10-0 sutures or a 2 mm filter paper soaked with sodium hydroxide in the central area of the cornea. At desired time points, the corneas were harvested for histology examination or for extraction of mRNA and protein. The mRNA levels of Saa1, Saa3, Fpr2, Mmp2 and Mmp3 in corneas were detected using quantitative reverse transcription-PCR, and SAA3 protein in tissues detected using immunohistochemistry or western blotting.RESULTS:Microarray data analysis revealed that Saa1, Saa3, Fpr2, Mmp2, Mmp3 messengers were readily detected in normal corneas and significantly up-regulated upon CorNV induction. The changes of these five genes were confirmed with real-time PCR assay. On the contrary, other SAA members (Saa2, Saa4, other SAA receptors (Tlr2, Tlr4, Cd36, P2rx7, etc, or other Mmps (Mmp1a, Mmp1b, Mmp9, Mmp10, Mmp13 did not show consistent changes. Immunohistochemistry study and western blotting further confirmed the expression of SAA3 products in normal corneas as well as their up-regulation in corneas with CorNV.CONCLUSION:SAA-FPR2 pathway composing genes were expressed in normal murine corneas and, upon inflammatory stimuli challenge to the corneas, their expressions were up-regulated, suggesting their roles in pathogenesis of CorNV. The potential usefulness of SAA-FPR2 targets in future management of CorNV-related diseases deserves investigation.

Sheng-Wei Ren

2014-04-01

205

A bacteriophage capsid protein provides a general amyloid interaction motif (GAIM) that binds and remodels misfolded protein assemblies.  

Science.gov (United States)

Misfolded protein aggregates, characterized by a canonical amyloid fold, play a central role in the pathobiology of neurodegenerative diseases. Agents that bind and sequester neurotoxic intermediates of amyloid assembly, inhibit the assembly or promote the destabilization of such protein aggregates are in clinical testing. Here, we show that the gene 3 protein (g3p) of filamentous bacteriophage mediates potent generic binding to the amyloid fold. We have characterized the amyloid binding and conformational remodeling activities using an array of techniques, including X-ray fiber diffraction and NMR. The mechanism for g3p binding with amyloid appears to reflect its physiological role during infection of Escherichia coli, which is dependent on temperature-sensitive interdomain unfolding and cis-trans prolyl isomerization of g3p. In addition, a natural receptor for g3p, TolA-C, competitively interferes with A? binding to g3p. NMR studies show that g3p binding to A? fibers is predominantly through middle and C-terminal residues of the A? subunit, indicating ? strand-g3p interactions. A recombinant bivalent g3p molecule, an immunoglobulin Fc (Ig) fusion of the two N-terminal g3p domains, (1) potently binds A? fibers (fA?) (KD=9.4nM); (2); blocks fA? assembly (IC50~50nM) and (3) dissociates fA? (EC50=40-100nM). The binding of g3p to misfolded protein assemblies is generic, and amyloid-targeted activities can be demonstrated using other misfolded protein systems. Taken together, our studies show that g3p(N1N2) acts as a general amyloid interaction motif. PMID:24768993

Krishnan, Rajaraman; Tsubery, Haim; Proschitsky, Ming Y; Asp, Eva; Lulu, Michal; Gilead, Sharon; Gartner, Myra; Waltho, Jonathan P; Davis, Peter J; Hounslow, Andrea M; Kirschner, Daniel A; Inouye, Hideyo; Myszka, David G; Wright, Jason; Solomon, Beka; Fisher, Richard A

2014-06-26

206

Protein Folding and Amyloid Formation: Good Questions for Solid State NMR  

Science.gov (United States)

Recent results from two ongoing projects will be described. These projects illustrate the expanding capability of solid state NMR spectroscopy to provide unique information about the molecular structure of complex biochemical systems that are of current interest in the biophysical and biomedical research communities. Methodological advances that facilitate progress on these projects will be discussed briefly. In the area of protein folding, we are using solid state NMR spectroscopy to characterize the distributions of molecular structures in unfolded and partially folded states of relatively simple model proteins. The measurements are carried out on frozen glassy solutions at low temperatures. Initial results for the chemical denaturation of the 35-residue helical protein HP35 show that unfolding does not occur by a simple two-state process and that local conformational distributions in the unfolded state are remarkably non-uniform. In the area of amyloid fibrils, we are using solid state NMR to develop experimentally-based models for the molecular structure of peptide fibrils associated with Alzheimer's disease and other amyloid diseases, and to develop an understanding of the interactions that stabilize amyloid fibril structures in general. The NMR data also reveal molecular-level polymorphism in amyloid fibrils, with implications for biomedical issues such as the etiological role of fibrils in amyloid diseases and the structural basis for strains in prion diseases.

Tycko, Robert

2005-03-01

207

Functional Analysis of the Accessory Protein TapA in Bacillus subtilis Amyloid Fiber Assembly  

OpenAIRE

Bacillus subtilis biofilm formation relies on the assembly of a fibrous scaffold formed by the protein TasA. TasA polymerizes into highly stable fibers with biochemical and morphological features of functional amyloids. Previously, we showed that assembly of TasA fibers requires the auxiliary protein TapA. In this study, we investigated the roles of TapA sequences from the C-terminal and N-terminal ends and TapA cysteine residues in its ability to promote the assembly of TasA amyloid-like fib...

Romero, Diego; Vlamakis, Hera; Losick, Richard; Kolter, Roberto

2014-01-01

208

The Purinergic Receptor P2X7 Triggers ?-Secretase-dependent Processing of the Amyloid Precursor Protein*  

OpenAIRE

The amyloid precursor protein (APP) is cleaved by ?- and ?-secretases to generate the ?-amyloid (A?) peptides, which are present in large amounts in the amyloid plaques of Alzheimer disease (AD) patient brains. Non-amyloidogenic processing of APP by ?-secretases leads to proteolytic cleavage within the A? peptide sequence and shedding of the soluble APP ectodomain (sAPP?), which has been reported to be endowed with neuroprotective properties. In this work, we have shown that activation...

Delarasse, Ce?cile; Auger, Rodolphe; Gonnord, Pauline; Fontaine, Bertrand; Kanellopoulos, Jean M.

2010-01-01

209

The roles of amyloid precursor protein (APP) in neurogenesis, implications to pathogenesis and therapy of Alzheimer disease (AD)  

OpenAIRE

The amyloid-beta (A?) peptide is the derivative of amyloid precursor protein (APP) generated through sequential proteolytic processing by ?- and ?-secretases. Excessive accumulation of A?, the main constituent of amyloid plaques, has been implicated in the etiology of Alzheimer disease (AD). It was found recently that the impairments of neurogenesis in brain were associated with the pathogenesis of AD. Furthermore recent findings implicated that APP could function to influence proliferati...

Zhou, Zhi-dong; Chan, Christine Hui-shan; Ma, Quan-hong; Xu, Xiao-hong; Xiao, Zhi-cheng; Tan, Eng-king

2011-01-01

210

Structure of a functional amyloid protein subunit computed using sequence variation.  

Science.gov (United States)

Functional amyloid fibers, called curli, play a critical role in adhesion and invasion of many bacteria. Unlike pathological amyloids, curli structures are formed by polypeptide sequences whose amyloid structure has been selected for during evolution. This important distinction provides us with an opportunity to obtain structural insights from an unexpected source: the covariation of amino acids in sequences of different curli proteins. We used recently developed methods to extract amino acid contacts from a multiple sequence alignment of homologues of the curli subunit protein, CsgA. Together with an efficient force field, these contacts allow us to determine structural models of CsgA. We find that CsgA forms a ?-helical structure, where each turn corresponds to previously identified repeat sequences in CsgA. The proposed structure is validated by previously measured solid-state NMR, electron microscopy, and X-ray diffraction data and agrees with an earlier proposed model derived by complementary means. PMID:25415595

Tian, Pengfei; Boomsma, Wouter; Wang, Yong; Otzen, Daniel E; Jensen, Mogens H; Lindorff-Larsen, Kresten

2015-01-14

211

A second pedigree with amyloid-less familial Alzheimer's disease harboring an identical mutation in the amyloid precursor protein gene (E693delta).  

Science.gov (United States)

A 59-year-old woman developed early-onset, slowly progressive dementia and spastic paraplegia. positron emission tomography (PET) imaging revealed a large reduction in the level of glucose uptake without amyloid deposition in the cerebral cortex. We identified a homozygous microdeletion within the amyloid ? (A?) coding sequence in the amyloid precursor protein (APP) gene (c.2080_2082delGAA, p.E693del) in three affected siblings and a heterozygous microdeletion in an unaffected sibling. The identical mutation was previously reported in the first Alzheimer's pedigree without amyloid deposits. Furthermore, an increase in high-molecular-weight A?-reactive bands was detected in the patient's CSF. Our findings suggest that soluble A?-oligomers induce neuronal toxicity, independent of insoluble A? fibrils. PMID:25743013

Kutoku, Yumiko; Ohsawa, Yutaka; Kuwano, Ryozo; Ikeuchi, Takeshi; Inoue, Haruhisa; Ataka, Suzuka; Shimada, Hiroyuki; Mori, Hiroshi; Sunada, Yoshihide

2015-01-01

212

Effect of x-radiation on serum proteins  

International Nuclear Information System (INIS)

The inbred albine mice were exposed to 315 roentgen whole-body X-radiation at a rate of 22.5 roentgen per minute. Maximum decrease in the serum albumin and maximum increase in the serum globulin fractions were seen two hours after irradiation. Both of the serum proteins return to approximately normal levels within six hours. (author)

213

Overactivation of calcineurin induced by amyloid-beta and prion proteins  

OpenAIRE

Amyloid-beta protein (A[beta]) and the scrapie isoform of prion protein (PrPSs) have a central role in the pathogenesis of Alzheimer's disease (AD) and prion-related encephalopathies (PRE), respectively. In both disorders, the deposition of these misfolded proteins is accompanied by apoptotic neuronal loss. However, the pathogenesis and molecular basis of A[beta]- and PrPSc-neurotoxic effects are not completely understood. The Ca2+/calmodulin-dependent phosphatase calcineurin (CaN), through t...

Agostinho, Paula; Lopes, Joa?o P.; Velez, Ze?lia; Oliveira, Catarina R.

2008-01-01

214

Dexras1 interacts with FE65 to regulate FE65-amyloid precursor protein-dependent transcription.  

OpenAIRE

FE65 is an adaptor protein that binds to and forms a transcriptionally active complex with the ?-secretase-derived amyloid precursor protein (APP) intracellular domain. The regulatory mechanisms of FE65-APP-mediated transcription are still not clear. In this report, we demonstrate that Dexras1, a Ras family small G protein, binds to FE65 PTB2 domain and potently suppresses the FE65-APP-mediated transcription. The suppression is not via competition for binding of FE65 ...

Mcloughlin, Declan

2008-01-01

215

Pre- and Postsynaptic Interaction of the Amyloid Precursor Protein Promotes Peripheral and Central Synaptogenesis  

OpenAIRE

A critical role of the amyloid precursor protein (APP) in Alzheimer's disease (AD) pathogenesis has been well established. However, the physiological function of APP remains elusive and much debated. We reported earlier that the APP family of proteins is essential in mediating the developing neuromuscular synapse. In the current study, we created a conditional allele of APP and deleted APP in presynaptic motor neuron or postsynaptic muscle. Crossing these alleles onto the APP like protein 2 n...

Wang, Zilai; Wang, Baiping; Yang, Li; Guo, Qinxi; Aithmitti, Nadia; Songyang, Zhou; Zheng, Hui

2009-01-01

216

Cell cycle-dependent regulation of the phosphorylation and metabolism of the Alzheimer amyloid precursor protein.  

OpenAIRE

Accumulation of the amyloid A beta peptide, which is derived from a larger precursor protein (APP), and the formation of plaques, are major events believed to be involved in the etiology of Alzheimer's disease. Abnormal regulation of the metabolism of APP may contribute to the deposition of plaques. APP is an integral membrane protein containing several putative phosphorylation sites within its cytoplasmic domain. We report here that APP is phosphorylated at Thr668 by p34cdc2 protein kinase (...

Suzuki, T.; Oishi, M.; Marshak, D. R.; Czernik, A. J.; Nairn, A. C.; Greengard, P.

1994-01-01

217

Multiplex Assay for Live-Cell Monitoring of Cellular Fates of Amyloid-? Precursor Protein (APP)  

OpenAIRE

Amyloid-? precursor protein (APP) plays a central role in pathogenesis of Alzheimer's disease. APP has a short half-life and undergoes complex proteolytic processing that is highly responsive to various stimuli such as changes in cellular lipid or energy homeostasis. Cellular trafficking of APP is controlled by its large protein interactome, including dozens of cytosolic adaptor proteins, and also by interactions with lipids. Currently, cellular regulation of APP is mostly studied based on a...

Merezhko, Maria; Muggalla, Pranuthi; Nyka?nen, Niko-petteri; Yan, Xu; Sakha, Prasanna; Huttunen, Henri J.

2014-01-01

218

Association of a novel human FE65-like protein with the cytoplasmic domain of the beta-amyloid precursor protein.  

OpenAIRE

We identified a novel human homologue of the rat FE65 gene, hFE65L, by screening the cytoplasmic domain of beta-amyloid precursor protein (beta PP) with the "interaction trap." The cytoplasmic domains of the beta PP homologues, APLP1 and APLP2 (amyloid precursor-like proteins), were also tested for interaction with hFE65L. APLP2, but not APLP1, was found to interact with hFE65L. We confirmed these interactions in vivo by successfully coimmunoprecipatating endogenous beta PP and APLP2 from mam...

Gue?nette, S. Y.; Chen, J.; Jondro, P. D.; Tanzi, R. E.

1996-01-01

219

Preparation of amyloid-like fibrils containing magnetic iron oxide nanoparticles: Effect of protein aggregation on proton relaxivity  

International Nuclear Information System (INIS)

Highlights: ? Preparation of amyloid materials labeled with magnetic iron oxide nanoparticles. ? Characterization of amyloid materials by electron tomography. ? Influence of protein aggregation on the magnetic nanoparticle properties. -- Abstract: A method to prepare amyloid-like fibrils functionalized with magnetic nanoparticles has been developed. The amyloid-like fibrils are prepared in a two step procedure, where insulin and magnetic nanoparticles are mixed simply by grinding in the solid state, resulting in a water soluble hybrid material. When the hybrid material is heated in aqueous acid, the insulin/nanoparticle hybrid material self assembles to form amyloid-like fibrils incorporating the magnetic nanoparticles. This results in magnetically labeled amyloid-like fibrils which has been characterized by Transmission Electron Microscopy (TEM) and electron tomography. The influence of the aggregation process on proton relaxivity is investigated. The prepared materials have potential uses in a range of bio-imaging applications.

220

Expression of human amyloid precursor protein in rat cortical neurons inhibits calcium oscillations.  

OpenAIRE

Synchronous calcium oscillations are observed in primary cultures of rat cortical neurons when mature networks are formed. This spontaneous neuronal activity needs an accurate control of calcium homeostasis. Alteration of intraneuronal calcium concentration is described in many neurodegenerative disorders, including Alzheimer disease (AD). Although processing of amyloid precursor protein (APP) that generates Abeta peptide has critical implications for AD pathogenesis, the neuronal function of...

Santos, Susana Ferrao; Pierrot, Nathalie; Morel, Nicole; Gailly, Philippe; Sindic, Christian; Octave, Jean-noe?l

2009-01-01

221

Amyloid precursor protein knockout diminishes synaptic vesicle proteins at the presynaptic active zone in mouse brain.  

Science.gov (United States)

The amyloid precursor protein (APP) has previously been allocated to an organellar pool residing in the Golgi apparatus and in endosomal compartments, and in its mature form to a presynaptic active zone-localized pool. By analyzing homozygous APP knockout mice we evaluated the impact of APP on synaptic vesicle protein abundance at synaptic release sites. Following immunopurification of synaptic vesicles and the attached presynaptic plasma membrane, individual proteins were subjected to quantitative Western blot analysis. We demonstrate that APP deletion in knockout animals reduces the abundance of the synaptic vesicle proteins synaptophysin, synaptotagmin-1, and SV2A at the presynaptic active zone. Conversely, deletion of the additional APP family members, APLP1 and APLP2 resulted in an increase in synaptophysin, synaptogamin-1, and SV2A abundance. When transmembrane APP is lacking in APPs?-KI/APLP2-KO mice synaptic vesicle protein abundance corresponds to that in APP -KO mice. Deletion of the synaptic vesicle protein 2 (SV2) A and B had no effect on APP and synaptophysin abundance but decreased synaptotagmin-1. Our data suggest that APP controls the abundance of synaptic vesicle proteins at the presynaptic release sites and thus impacts synaptic transmission. PMID:25387333

Laßek, Melanie; Weingarten, Jens; Acker-Palmer, Amparo; Bajjalieh, Sandra M; Muller, Ulrike; Volknandt, Walter

2014-01-01

222

The cellular prion protein traps Alzheimer's A? in an oligomeric form and disassembles amyloid fibers  

OpenAIRE

There is now strong evidence to show that the presence of the cellular prion protein (PrPC) mediates amyloid-? (A?) neurotoxicity in Alzheimer's disease (AD). Here, we probe the molecular details of the interaction between PrPC and A? and discover that substoichiometric amounts of PrPC, as little as 1/20, relative to A? will strongly inhibit amyloid fibril formation. This effect is specific to the unstructured N-terminal domain of PrPC. Electron microscopy indicates PrPC is able to trap A...

Younan, Nadine D.; Sarell, Claire J.; Davies, Paul; Brown, David R.; Viles, John H.

2013-01-01

223

Effects of the amyloid precursor protein Glu693-->Gln 'Dutch' mutation on the production and stability of amyloid beta-protein.  

Science.gov (United States)

Hereditary cerebral haemorrhage with amyloidosis, Dutch type (HCHWA-D), is a cerebral amyloidosis characterized by prominent vascular deposits and fatal haemorrhages. The disorder is caused by a point mutation in codon 693 of the gene encoding the amyloid precursor protein (APP), resulting in a Glu-->Gln amino acid substitution at position 22 of the amyloid beta-protein (Abeta) region. The pathogenetic mechanisms of HCHWA-D are unknown but could involve alterations in the proteolytic processing of APP and in amyloid fibril formation. We examined Abeta production and stability by using cultured human embryonic kidney 293 cells stably expressing wild-type or 'Dutch' APP. Radiosequencing and quantitative immunoprecipitation experiments showed that cells expressing Dutch APP secreted increased quantities of Abeta peptides beginning at Asp1, and of truncated peptides beginning at Val18 and Phe19. The ratio of levels of 4 kDa (Abeta) to 3 kDa (p3) peptides remained constant due to co-ordinate decreases in other peptide species. Novel truncated or elongated peptides were not observed. Pulse-chase experiments showed that the Dutch mutation did not affect the stability of the Abeta or p3 populations. These results are consistent with a disease process in which the Dutch mutation results in the production of Abeta peptides with enhanced propensities for fibrillogenesis, leading to accelerated vascular deposition and disease. PMID:10359654

Watson, D J; Selkoe, D J; Teplow, D B

1999-01-01

224

Molecular cloning, characterization of one key molecule of teleost innate immunity from orange-spotted grouper (Epinephelus coioides): serum amyloid A.  

Science.gov (United States)

The orange-spotted grouper (Epinephelus coioides), a favorite marine food fish, is widely cultured in China and Southeast Asian countries. However, little is known about its acute phase response (APR) caused by viral diseases. Serum amyloid A (SAA) is a major acute phase protein (APP). In this study, a new SAA homologous (EcSAA) gene was cloned from grouper, E. coioides, by rapid amplification of cDNA ends (RACE) PCR. The full-length cDNA sequence of SAA was 508 bp and contained a 363 bp open reading frame (ORF) coding for a protein of 121 aa. Similar to other fish known SAA genes, the EcSAA gene contained four exons and three introns. Quantitative real-time PCR analysis revealed that EcSAA mRNA is predominately expressed in liver and gill of grouper. Furthermore, the expression of EcSAA was differentially up-regulated in liver after infection with Staphyloccocus aureus, Vibrio vulnificus, Vibrio parahaemolyticus, Saccharomyces cerevisiae and Singapore grouper iridovirus (SGIV). Recombinant EcSAA (rEcSAA) was expressed in Escherichia BL21 (DE3) and purified for mouse anti-EcSAA serum preparation. The rEcSAA fusion protein was demonstrated to bind to all tested bacteria and yeast, and inhibit the replication of SGIV. Overexpression of EcSAA in grouper spleen (GS) cells could also inhibit the replication of SGIV. These results suggest that EcSAA may be an important molecule in the innate immunity of grouper. PMID:23178260

Wei, Jingguang; Guo, Minglan; Ji, Huasong; Qin, Qiwei

2013-01-01

225

Mechanism of amyloid ?-protein aggregation mediated by GM1 ganglioside clusters.  

Science.gov (United States)

It is widely accepted that the conversion of the soluble, nontoxic amyloid ?-protein (A?) monomer to aggregated toxic A? rich in ?-sheet structures is central to the development of Alzheimer's disease. However, the mechanism of the abnormal aggregation of A? in vivo is not well understood. We have proposed that ganglioside clusters in lipid rafts mediate the formation of amyloid fibrils by A?, the toxicity and physicochemical properties of which are different from those of amyloids formed in solution. In this paper, the mechanism by which A?-(1-40) fibrillizes in raftlike lipid bilayers composed of monosialoganglioside GM1, cholesterol, and sphingomyelin was investigated in detail on the basis of singular-value decomposition of circular dichroism data and analysis of fibrillization kinetics. At lower protein densities in the membrane (A?:GM1 ratio of less than ?0.013), only the helical species exists. At intermediate protein densities (A?:GM1 ratio between ?0.013 and ?0.044), the helical species and aggregated ?-sheets (?15-mer) coexist. However, the ?-structure is stable and does not form larger aggregates. At A?:GM1 ratios above ?0.044, the ?-structure is converted to a second, seed-prone ?-structure. The seed recruits monomers from the aqueous phase to form amyloid fibrils. These results will shed light on a molecular mechanism for the pathogenesis of the disease. PMID:21682276

Ikeda, Keisuke; Yamaguchi, Takahiro; Fukunaga, Saori; Hoshino, Masaru; Matsuzaki, Katsumi

2011-07-26

226

Nerve growth factor modulates the expression and secretion of ?-amyloid precursor protein through different mechanisms in PC12 cells  

OpenAIRE

The ?-amyloid protein, component of the senile plaques found in Alzheimer brains is proteolytically derived from the ?-amyloid precursor protein (APP), a larger membrane-associated protein that is expressed in both neural and nonneural cells. Overexpression of APP might be one of the mechanisms that more directly contributes to the development of Alzheimer's disease. The APP gene expression is regulated by a number of cellular mediators including nerve growth factor (NGF) and other ligands ...

Villa, Ana; Latasa, Mari?a Jesu?s; Pascual, A?ngel

2001-01-01

227

Transfer of beta-amyloid precursor protein gene using adenovirus vector causes mitochondrial abnormalities in cultured normal human muscle.  

OpenAIRE

As in Alzheimer-disease (AD) brain, vacuolated muscle fibers of inclusion-body myositis (IBM) contain abnormally accumulated beta-amyloid precursor protein (beta APP), including its beta-amyloid protein epitope, and increased beta APP-751 mRNA. Other similarities between IBM muscle and AD brain phenotypes include paired helical filaments, hyperphosphorylated tau protein, apolipoprotein E, and mitochondrial abnormalities, including decreased cytochrome-c oxidase (COX) activity. The pathogenesi...

Askanas, V.; Mcferrin, J.; Baque?, S.; Alvarez, R. B.; Sarkozi, E.; Engel, W. K.

1996-01-01

228

Activation of extrasynaptic, but not synaptic, NMDA receptors modifies amyloid precursor protein expression pattern and increases amyloid-ß production.  

Science.gov (United States)

Calcium is a key mediator controlling essential neuronal functions depending on electrical activity. Altered neuronal calcium homeostasis affects metabolism of amyloid precursor protein (APP), leading to increased production of ?-amyloid (A?), and contributing to the initiation of Alzheimer's disease (AD). A linkage between excessive glutamate receptor activation and neuronal A? release was established, and recent reports suggest that synaptic and extrasynaptic NMDA receptor (NMDAR) activation may have distinct consequences in plasticity, gene regulation, and neuronal death. Here, we report for the first time that prolonged activation of extrasynaptic NMDAR, but not synaptic NMDAR, dramatically increased the neuronal production of A?. This effect was preceded by a shift from APP695 to Kunitz protease inhibitory domain (KPI) containing APPs (KPI-APPs), isoforms exhibiting an important amyloidogenic potential. Conversely, after synaptic NMDAR activation, we failed to detect any KPI-APP expression and neuronal A? production was not modified. Calcium imaging data showed that intracellular calcium concentration after extrasynaptic NMDAR stimulation was lower than after synaptic activation. This suggests distinct signaling pathways for each pool of receptors. We found that modification of neuronal APP expression pattern triggered by extrasynaptic NMDAR activation was regulated at an alternative splicing level involving calcium-/calmodulin-dependent protein kinase IV, but overall APP expression remained identical. Finally, memantine dose-dependently inhibited extrasynaptic NMDAR-induced KPI-APPs expression as well as neuronal A? release. Altogether, these data suggest that a chronic activation of extrasynaptic NMDAR promotes amyloidogenic KPI-APP expression leading to neuronal A? release, representing a causal risk factor for developing AD. PMID:21106831

Bordji, Karim; Becerril-Ortega, Javier; Nicole, Olivier; Buisson, Alain

2010-11-24

229

Phagocytosis and LPS alter the maturation state of ?-amyloid precursor protein and induce different A? peptide release signatures in human mononuclear phagocytes  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The classic neuritic ?-amyloid plaque of Alzheimer's disease (AD is typically associated with activated microglia and neuroinflammation. Similarly, cerebrovascular ?-amyloid (A? deposits are surrounded by perivascular macrophages. Both observations indicate a contribution of the mononuclear phagocyte system to the development of ?-amyloid. Methods Human CD14-positive mononuclear phagocytes were isolated from EDTA-anticoagulated blood by magnetic activated cell sorting. After a cultivation period of 72 hours in serum-free medium we assessed the protein levels of amyloid precursor protein (APP as well as the patterns and the amounts of released A? peptides by ELISA or one-dimensional and two-dimensional urea-based SDS-PAGE followed by western immunoblotting. Results We observed strong and significant increases in A? peptide release upon phagocytosis of acetylated low density lipoprotein (acLDL or polystyrene beads and also after activation of the CD14/TLR4 pathway by stimulation with LPS. The proportion of released N-terminally truncated A? variants was increased after stimulation with polystyrene beads and acLDL but not after stimulation with LPS. Furthermore, strong shifts in the proportions of single A?1-40 and A?2-40 variants were detected resulting in a stimulus-specific A? signature. The increased release of A? peptides was accompanied by elevated levels of full length APP in the cells. The maturation state of APP was correlated with the release of N-terminally truncated A? peptides. Conclusions These findings indicate that mononuclear phagocytes potentially contribute to the various N-truncated A? variants found in AD ?-amyloid plaques, especially under neuroinflammatory conditions.

Kornhuber Johannes

2010-10-01

230

A link between inflammation and metastasis: serum amyloid A1 and A3 induce metastasis, and are targets of metastasis-inducing S100A4.  

Science.gov (United States)

S100A4 is implicated in metastasis and chronic inflammation, but its function remains uncertain. Here we establish an S100A4-dependent link between inflammation and metastatic tumor progression. We found that the acute-phase response proteins serum amyloid A (SAA) 1 and SAA3 are transcriptional targets of S100A4 via Toll-like receptor 4 (TLR4)/nuclear factor-?B signaling. SAA proteins stimulated the transcription of RANTES (regulated upon activation normal T-cell expressed and presumably secreted), G-CSF (granulocyte-colony-stimulating factor) and MMP2 (matrix metalloproteinase 2), MMP3, MMP9 and MMP13. We have also shown for the first time that SAA stimulate their own transcription as well as that of proinflammatory S100A8 and S100A9 proteins. Moreover, they strongly enhanced tumor cell adhesion to fibronectin, and stimulated migration and invasion of human and mouse tumor cells. Intravenously injected S100A4 protein induced expression of SAA proteins and cytokines in an organ-specific manner. In a breast cancer animal model, ectopic expression of SAA1 or SAA3 in tumor cells potently promoted widespread metastasis formation accompanied by a massive infiltration of immune cells. Furthermore, coordinate expression of S100A4 and SAA in tumor samples from colorectal carcinoma patients significantly correlated with reduced overall survival. These data show that SAA proteins are effectors for the metastasis-promoting functions of S100A4, and serve as a link between inflammation and tumor progression. PMID:24469032

Hansen, M T; Forst, B; Cremers, N; Quagliata, L; Ambartsumian, N; Grum-Schwensen, B; Klingelhöfer, J; Abdul-Al, A; Herrmann, P; Osterland, M; Stein, U; Nielsen, G H; Scherer, P E; Lukanidin, E; Sleeman, J P; Grigorian, M

2015-01-22

231

Crystal Structure of the E2 Domain of Amyloid Precursor Protein-like Protein 1 in Complex with Sucrose Octasulfate*  

OpenAIRE

Missense mutations in the amyloid precursor protein (APP) gene can cause familial Alzheimer disease. It is thought that APP and APP-like proteins (APLPs) may play a role in adhesion and signal transduction because their ectodomains interact with components of the extracellular matrix. Heparin binding induces dimerization of APP and APLPs. To help explain how these proteins interact with heparin, we have determined the crystal structure of the E2 domain of APLP1 in complex with sucrose octasul...

Xue, Yi; Lee, Sangwon; Wang, Yongcheng; Ha, Ya

2011-01-01

232

Heterocomplexes of mannose-binding lectin and the pentraxins PTX3 or serum amyloid P component trigger cross-activation of the complement system  

DEFF Research Database (Denmark)

The long pentraxin 3 (PTX3), serum amyloid P component (SAP), and C-reactive protein belong to the pentraxin family of pattern recognition molecules involved in tissue homeostasis and innate immunity. They interact with C1q from the classical complement pathway. Whether this also occurs via the analogous mannose-binding lectin (MBL) from the lectin complement pathway is unknown. Thus, we investigated the possible interaction between MBL and the pentraxins. We report that MBL bound PTX3 and SAP partly via its collagen-like domain but not C-reactive protein. MBL-PTX3 complex formation resulted in recruitment of C1q, but this was not seen for the MBL-SAP complex. However, both MBL-PTX3 and MBL-SAP complexes enhanced C4 and C3 deposition and opsonophagocytosis of Candida albicans by polymorphonuclear leukocytes. Interaction between MBL and PTX3 led to communication between the lectin and classical complement pathways via recruitment of C1q, whereas SAP-enhanced complement activation occurs via a hitherto unknown mechanism. Taken together, MBL-pentraxin heterocomplexes trigger cross-activation of the complement system.

Ma, Ying Jie; Doni, Andrea

2011-01-01

233

Epigenetic Induction of EGR-1 Expression by the Amyloid Precursor Protein during Exposure to Novelty  

OpenAIRE

Following transcriptome comparison of primary cultures isolated from brain of mice expressing or not the amyloid precursor protein APP, we found transcription of the EGR-1 gene to be regulated by APP. In primary cultures of cortical neurons, APP significantly down regulated EGR-1 expression at both mRNA and protein levels in a ?-secretase independent manner. The intracellular domain of APP did not interact with EGR-1 gene promoter, but enrichment of acetylated histone H4 at the EGR-1 promote...

Hendrickx, Aure?lie; Pierrot, Nathalie; Tasiaux, Bernadette; Schakman, Olivier; Brion, Jean-pierre; Kienlen-campard, Pascal; Smet, Charles; Octave, Jean-noe?l

2013-01-01

234

A ?-Secretase-independent Mechanism of Signal Transduction by the Amyloid Precursor Protein*  

OpenAIRE

It has been proposed that ?-secretase-mediated release of the amyloid precursor protein (APP) intracellular domain (AICD) results in nuclear translocation and signaling through a complex with the adaptor protein Fe65 and the histone acetyltransferase Tip60. Here, we show that APP and Fe65 activate transcription through a Gal4-Tip60 reporter in presenilin-1/2-deficient cells lacking generation of AICD. APP and Fe65 also activated transcription in the presence of ?-secretase inhibitors that p...

Hass, Matthew R.; Yankner, Bruce A.

2005-01-01

235

Turnover of amyloid precursor protein family members determines their nuclear signaling capability  

OpenAIRE

The amyloid precursor protein (APP) as well as its homologues, APP-like protein 1 and 2 (APLP1 and APLP2), are cleaved by ??-, ??-, and ??-secretases, resulting in the release of their intracellular domains (ICDs). We have shown that the APP intracellular domain (AICD) is transported to the nucleus by Fe65 where they jointly bind the histone acetyltransferase Tip60 and localize to spherical nuclear complexes (AFT complexes), which are thought to be sites of transcription. We have ...

Gersbacher, Manuel T.; Goodger, Zo?? V.; Trutzel, Annette; Bundschuh, Diana; Nitsch, Roger M.; Konietzko, Uwe

2013-01-01

236

Systematic evaluation of candidate ligands regulating ectodomain shedding of Amyloid Precursor Protein  

OpenAIRE

Despite intense interest in the proteolysis of the ß-Amyloid Precursor Protein (APP) in Alzheimer's disease (AD), how the normal processing of this type I receptor-like glycoprotein is physiologically regulated remains ill-defined. In recent years, several candidate protein ligands for APP, including F-spondin, Reelin, ?1 Integrin, Contactins, Lingo-1 and Pancortin, have been reported. However, a cognate ligand for APP that regulates its processing by ?- or ?-secretase has yet to be widel...

Rice, Heather C.; Young-pearse, Tracy L.; Selkoe, Dennis J.

2013-01-01

237

Are amyloid diseases caused by protein aggregates that mimic bacterial pore-forming toxins?  

OpenAIRE

Protein fibrillization is implicated in the pathogenesis of most, if not all, age-associated neurodegenerative diseases, but the mechanism(s) by which it triggers neuronal death is unknown. Reductionist in vitro studies suggest that the amyloid protofibril may be the toxic species and that it may amplify itself by inhibiting proteasome-dependent protein degradation. Although its pathogenic target has not been identified, the properties of the protofibril suggest that neurons could be killed b...

Lashuel, Hilal A.; Lansbury, Peter T.

2006-01-01

238

Amyloid precursor protein mediates monocyte adhesion in AD tissue and ApoE?/? mice  

OpenAIRE

Amyloid precursor protein (APP) is a type 1 integral membrane protein which is highly conserved and ubiquitously expressed. Numerous data suggest it functions in cellular adhesion. For example, APP binds components of the extracellular matrix to propagate intracellular signaling responses. In order to investigate adhesion-related changes in inflamed vasculature, brains from apolipoprotein E ?/? (apoE?/?) mice were examined for changes related to APP then compared to human Alzheimer’...

Austin, Susan A.; Combs, Colin K.

2008-01-01

239

Observation of sequence specificity in the seeding of protein amyloid fibrils  

OpenAIRE

It is well established that the rate of formation of fibrils by amyloidogenic proteins is enhanced by the addition of preformed fibrils, a phenomenon known as seeding. We show that the efficiency of seeding fibril formation from solutions of hen lysozyme by a series of other proteins depends strongly on the similarity of their sequences. This observation is consistent with the importance of long-range interactions in stabilizing the core structure of amyloid fibrils and may be associated with...

Krebs, MR; Morozova-roche, La; Daniel, K.; Robinson, Cv; Dobson, Cm

2004-01-01

240

Elemental analysis of human serum and serum protein fractions by thermal neutron activation  

International Nuclear Information System (INIS)

Some applications of thermal neutron activation for the determination of elemental contents in human serum and human serum protein fractions are presented. Firstly total serum is dealt with, secondly serum protein fractions obtained by gel filtration are described. A brief review on the role of (trace) elements in human health and disease and a compilation of literature data for elemental contents in human serum, as obtained by neutron activation techniques, are given. The most important sources of statistical and systematic errors are evaluated. Results for the contents of sodium, potassium, magnesium, bromine, iron, copper, zinc, selenium, rubidium, cesium and antimony in serum are given, with emphasis on control of accuracy and precision. The possible relation between selenium in blood and cancer occurrence in humans is discussed. The results of elemental analyses from cancer patients and from a patient receiving a cytostatic treatment are presented. A survey of literature results for the determination of protein-bound elemental contents in serum is presented. Subsequently, results from a study on the behaviour of elements during gel filtration are discussed. Gel-element and protein-element interactions are studied. Finally the protein-bound occurrence of trace elements in human serum is determined by gel filtration and neutron activation analysis. Results for both desalting and fractionation are given, for the elements bromine, copper, manganese, vanadium, selenium, zinc, rubidium, iron and iodine. (Auth.)

241

Effects of serum, its protein and lipid extracts, and commercial serum proteins and lipid on the isolated frog heart.  

Science.gov (United States)

This study investigates the inotropic effects of serum, its protein and lipid extracts, and commercial serum proteins and lipid on the isolated, spontaneously-beating heart and superfused, hypodynamic ventricle of the frog. Serum taken from either man, horse, calf, frog, or rabbit evoked marked positive inotropic responses which were unaffected by cholinergic, serotonergic, and adrenergic receptor antagonists. Dialysed serum (dialisand) and void volume fractions from Sephadex G200-120 columns corresponding to large molecular weight constituents evoked marked positive inotropic responses. When serum was separated into fractions containing either proteins or lipids/lipoproteins by high-density ultracentrifugation or activated charcoal, both extracts evoked marked positive inotropic responses. Commercial serum globulins and serum containing a high proportion of immunoglobulins elicited large increases in contractile force, whereas serum albumin evoked a negative inotropic effect. Serum which was either boiled and/or treated with chymotrypsin to denature proteins also caused a marked increase in isometric twitch tension in the frog heart. Similar inotropic response was obtained with fractions of boiled serum eluted on columns of Sephadex G200-120. These fractions corresponded to molecular weight in the region of 60-70 kDa. However, the inotropic effect of boiled serum was abolished following pretreatment with lipase. Superfusion of frog hearts with commercial cardiolipin resulted in marked dose-dependent increases in contractile force. The results demonstrate the presence of at least two large molecular weight cardioactive principles in serum. These substances are comparable in size to constituents of serum proteins (e.g., globulins and immunoglobulins) and serum lipids/lipoproteins (e.g., cardiolipin) and may serve as physiological regulators of cardiac function. PMID:1939740

Singh, J; Hutton, T; Hussain, M; Waring, J J

1991-01-01

242

Dual amyloid domains promote differential functioning of the chaplin proteins during Streptomyces aerial morphogenesis  

Science.gov (United States)

The chaplin proteins are functional amyloids found in the filamentous Streptomyces bacteria. These secreted proteins are required for the aerial development of Streptomyces coelicolor, and contribute to an intricate rodlet ultrastructure that decorates the surfaces of aerial hyphae and spores. S. coelicolor encodes eight chaplin proteins. Previous studies have revealed that only three of these proteins (ChpC, ChpE, and ChpH) are necessary for promoting aerial development, and of these three, ChpH is the primary developmental determinant. Here, we show that the model chaplin, ChpH, contains two amyloidogenic domains: one in the N terminus and one in the C terminus of the mature protein. These domains have different polymerization properties as determined using fluorescence spectroscopy, secondary structure analyses, and electron microscopy. We coupled these in vitro assays with in vivo genetic studies to probe the connection between ChpH amyloidogenesis and its biological function. Using mutational analyses, we demonstrated that both N- and C-terminal amyloid domains of ChpH were required for promoting aerial hypha formation, while the N-terminal domain was dispensable for assembly of the rodlet ultrastructure. These results suggest that there is a functional differentiation of the dual amyloid domains in the chaplin proteins. PMID:21628577

Capstick, David S.; Jomaa, Ahmad; Hanke, Chistopher; Ortega, Joaquin; Elliot, Marie A.

2011-01-01

243

Hook Proteins: Association with Alzheimer Pathology and Regulatory Role of Hook3 in Amyloid Beta Generation  

Science.gov (United States)

Defects in intracellular transport are implicated in the pathogenesis of Alzheimer’s disease (AD). Hook proteins are a family of cytoplasmic linker proteins that participate in endosomal transport. In this study we show that Hook1 and Hook3 are expressed in neurons while Hook2 is predominantly expressed in astrocytes. Furthermore, Hook proteins are associated with pathological hallmarks in AD; Hook1 and Hook3 are localized to tau aggregates and Hook2 to glial components within amyloid plaques. Additionally, the expression of Hook3 is reduced in AD. Modelling of Hook3 deficiency in cultured cells leads to slowing of endosomal transport and increases ?-amyloid production. We propose that Hook3 plays a role in pathogenic events exacerbating AD. PMID:25799409

Arsalan-Werner, Annika; Hilbrich, Isabel; Jäger, Carsten; Flach, Katharina; Suttkus, Anne; Lachmann, Ingolf; Arendt, Thomas; Holzer, Max

2015-01-01

244

Observation of sequence specificity in the seeding of protein amyloid fibrils.  

Science.gov (United States)

It is well established that the rate of formation of fibrils by amyloidogenic proteins is enhanced by the addition of preformed fibrils, a phenomenon known as seeding. We show that the efficiency of seeding fibril formation from solutions of hen lysozyme by a series of other proteins depends strongly on the similarity of their sequences. This observation is consistent with the importance of long-range interactions in stabilizing the core structure of amyloid fibrils and may be associated with the existence of a species barrier observed in the transmissible spongiform encephalopathies. In addition, it is consistent with the observation of a single dominant type of protein in the deposits associated with each form of amyloid disease. PMID:15215533

Krebs, Mark R H; Morozova-Roche, Ludmilla A; Daniel, Katie; Robinson, Carol V; Dobson, Christopher M

2004-07-01

245

Hydration, cavities and volume in protein folding, aggregation and amyloid assembly  

International Nuclear Information System (INIS)

Differential hydration dictates various biological processes, including protein folding, ligand binding, macromolecular assembly, enzyme kinetics and signal transduction. If water is partially or totally removed (experimentally or in silico), the outcome of these processes can be significantly affected. The aggregation of proteins into amyloids or other aggregate forms also results in profound changes in hydration. High hydrostatic pressure is a unique tool to study hydration, as increases in water binding usually lead to decreases in volume. Pressure changes can favor the formation or disassembly of amyloids depending on the volume changes associated with protein folding and misfolding/aggregation. The packing and formation of cavities will also contribute to changes in volume, and therefore, to sensitivity to pressure. Therefore, the formation of water-excluding cavities is predicted to be an important event in folding and aggregation landscapes

246

Estrogen protects neuronal cells from amyloid beta-induced apoptosis via regulation of mitochondrial proteins and function  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Neurodegeneration in Alzheimer's disease is associated with increased apoptosis and parallels increased levels of amyloid beta, which can induce neuronal apoptosis. Estrogen exposure prior to neurotoxic insult of hippocampal neurons promotes neuronal defence and survival against neurodegenerative insults including amyloid beta. Although all underlying molecular mechanisms of amyloid beta neurotoxicity remain undetermined, mitochondrial dysfunction, including altered calcium homeostasis and Bcl-2 expression, are involved in neurodegenerative vulnerability. Results In this study, we investigated the mechanism of 17?-estradiol-induced prevention of amyloid beta-induced apoptosis of rat hippocampal neuronal cultures. Estradiol treatment prior to amyloid beta exposure significantly reduced the number of apoptotic neurons and the associated rise in resting intracellular calcium levels. Amyloid beta exposure provoked down regulation of a key antiapoptotic protein, Bcl-2, and resulted in mitochondrial translocation of Bax, a protein known to promote cell death, and subsequent release of cytochrome c. E2 pretreatment inhibited the amyloid beta-induced decrease in Bcl-2 expression, translocation of Bax to the mitochondria and subsequent release of cytochrome c. Further implicating the mitochondria as a target of estradiol action, in vivo estradiol treatment enhanced the respiratory function of whole brain mitochondria. In addition, estradiol pretreatment protected isolated mitochondria against calcium-induced loss of respiratory function. Conclusion Therefore, we propose that estradiol pretreatment protects against amyloid beta neurotoxicity by limiting mitochondrial dysfunction via activation of antiapoptotic mechanisms.

Iwamoto Sean

2006-11-01

247

Wild-type Shadoo proteins convert to amyloid-like forms under native conditions.  

Science.gov (United States)

The cellular prion protein PrP(C) refolds into a beta-sheet enriched, infectivity-associated form called PrP(Sc). Shadoo (Sho) is a newly discovered glycoprotein that is also expressed in the adult brain. Wild type (wt) mouse Sho consists of an arginine-rich region, a hydrophobic central domain of five tandem A/LAAG amino acid repeats R1-R5 with similarity to the hydrophobic domain of PrP(C), and a C-terminal domain with one N-linked carbohydrate. As some alanine-rich proteins and PrP with a shortened C-terminal domain form amyloid we investigated conformational properties of wt Sho and polymorphic variants with insertion/deletions centered on R3. Recombinant mouse and sheep Sho converted to an amyloid-like form without recourse to chemical denaturation or acidification. For wt proteins this transition was marked by increased thioflavin T binding, Congo red staining, presence of fibrillar structures by electron microscopy, formation of sodium dodecyl sulfate-resistant complexes and the generation of a C-terminal proteinase K resistant core of 5-8 kDa. Variant Sho proteins differing within the R1-R5 region exhibited most but not all of these properties. Our studies define a proteinase K -resistant signature fragment for the amyloid fold of Sho and raise the question of a physiological role for this form of the wt protein. PMID:20067571

Daude, Nathalie; Ng, Vivian; Watts, Joel C; Genovesi, Sacha; Glaves, John Paul; Wohlgemuth, Serene; Schmitt-Ulms, Gerold; Young, Howard; McLaurin, Joanne; Fraser, Paul E; Westaway, David

2010-04-01

248

Mapping of the gene encoding the ?-amyloid precursor protein and its relationship to the Down syndrome region of chromosome 21  

International Nuclear Information System (INIS)

The gene encoding the ?-amyloid precursor protein has been assigned to human chromosome 21, as has a gene responsible for at least some cases of familial Alzheimer disease. Linkage studies strongly suggest that the ?-amyloid precursor protein and the product corresponding to familial Alzheimer disease are from two genes, or at least that several million base pairs of DNA separate the markers. The precise location of the ?-amyloid precursor protein gene on chromosome 21 has not yet been determined. Here the authors show, by using a somatic-cell/hybrid-cell mapping panel, in situ hybridization, and transverse-alternating-field electrophoresis, that the ?-amyloid precursor protein gene is located on chromosome 21 very near the 21q21/21q/22 border and probably within the region of chromosome 21 that, when trisomic, results in Down syndrome

249

Differential regulation of amyloid-. beta. -protein mRNA expression within hippocampal neuronal subpopulations in Alzheimer disease  

Energy Technology Data Exchange (ETDEWEB)

The authors have mapped the neuroanatomical distribution of amyloid-..beta..-protein mRNA within neuronal subpopulations of the hippocampal formation in the cynomolgus monkey (Macaca fascicularis), normal aged human, and patients with Alzheimer disease. Amyloid-..beta..-protein mRNA appears to be expressed in all hippocampal neurons, but at different levels of abundance. In the central nervous system of monkey and normal aged human, image analysis shows that neurons of the dentate gyrus and cornu Ammonis fields contain a 2.5-times-greater hybridization signal than is present in neurons of the subiculum and entorhinal cortex. In contrast, in the Alzheimer disease hippocampal formation, the levels of amyloid-..beta..-protein mRNA in the cornu Ammonis field 3 and parasubiculum are equivalent. These findings suggest that within certain neuronal subpopulations cell type-specific regulation of amyloid-..beta..-protein gene expression may be altered in Alzheimer disease.

Higgins, G.A.; Lewis, D.A.; Bahmanyar, S.; Goldgaber, D.; Gajdusek, D.C.; Young, W.G.; Morrison, J.H.; Wilson, M.C.

1988-02-01

250

Differential regulation of amyloid-?-protein mRNA expression within hippocampal neuronal subpopulations in Alzheimer disease  

International Nuclear Information System (INIS)

The authors have mapped the neuroanatomical distribution of amyloid-?-protein mRNA within neuronal subpopulations of the hippocampal formation in the cynomolgus monkey (Macaca fascicularis), normal aged human, and patients with Alzheimer disease. Amyloid-?-protein mRNA appears to be expressed in all hippocampal neurons, but at different levels of abundance. In the central nervous system of monkey and normal aged human, image analysis shows that neurons of the dentate gyrus and cornu Ammonis fields contain a 2.5-times-greater hybridization signal than is present in neurons of the subiculum and entorhinal cortex. In contrast, in the Alzheimer disease hippocampal formation, the levels of amyloid-?-protein mRNA in the cornu Ammonis field 3 and parasubiculum are equivalent. These findings suggest that within certain neuronal subpopulations cell type-specific regulation of amyloid-?-protein gene expression may be altered in Alzheimer disease

251

Sensing of Proteins in Human Serum using Nanoparticle-Green Fluorescent Protein Conjugates  

OpenAIRE

There is a direct correlation between protein levels and disease states in human serum making it an attractive target for sensors and diagnostics. However this is made challenging because serum features more than 20,000 proteins with an overall protein content of greater than 1 mM. Here we report a hybrid synthetic-biomolecule based sensor that uses green fluorescent protein-nanoparticle arrays to detect proteins at biorelevant concentrations in both buffer and human serum. Distinct and repro...

DE, MRINMOY; Rana, Subinoy; Akpinar, Handan; Miranda, Oscar R.; Arvizo, Rochelle R.; Bunz, Uwe H. F.; Rotello, Vincent M.

2009-01-01

252

Molecular simulations of beta-amyloid protein near hydrated lipids (PECASE).  

Energy Technology Data Exchange (ETDEWEB)

We performed molecular dynamics simulations of beta-amyloid (A{beta}) protein and A{beta} fragment(31-42) in bulk water and near hydrated lipids to study the mechanism of neurotoxicity associated with the aggregation of the protein. We constructed full atomistic models using Cerius2 and ran simulations using LAMMPS. MD simulations with different conformations and positions of the protein fragment were performed. Thermodynamic properties were compared with previous literature and the results were analyzed. Longer simulations and data analyses based on the free energy profiles along the distance between the protein and the interface are ongoing.

Thompson, Aidan Patrick; Han, Kunwoo (Texas A& M University, College Station, TX); Ford, David M. (Texas A& M University, College Station, TX)

2005-12-01

253

Evidence that. beta. -amyloid protein in Alzheimer's disease is not derived by normal processing  

Energy Technology Data Exchange (ETDEWEB)

The {beta}-amyloid protein ({beta}/A4), derived from a larger amyloid precursor protein (APP), is the principal component of senile plaques in Alzheimer's disease. APP is an integral membrane glycoprotein and is secreted as a carboxyl-terminal truncated molecule. APP cleavage, which is a membrane-associated event, occurred at a site located within the {beta}/A4 region. This suggests that an intact amyloidogenic {beta}/A4 fragment is not generated during normal APP catabolism. Therefore, an early event in amyloid formation may involve altered APP processing that results in the release and subsequent deposition of intact {beta}/A4.

Sisodia, S.S.; Koo, E.H.; Price, D.L. (Johns Hopkins Univ. School of Medicine, Baltimore, MD (USA)); Beyreuther, K. (Univ. of Heidelberg (West Germany)); Unterbeck, A. (Molecular Therapeutics, West Haven, CT (USA))

1990-04-27

254

Studies of the aggregation of mutant proteins in vitro provide insights into the genetics of amyloid diseases  

OpenAIRE

Protein aggregation and the formation of highly insoluble amyloid structures is associated with a range of debilitating human conditions, which include Alzheimer's disease, Parkinson's disease, and the Creutzfeldt–Jakob disease. Muscle acylphosphatase (AcP) has already provided significant insights into mutational changes that modulate amyloid formation. In the present paper, we have used this system to investigate the effects of mutations that modify the charge state of a protein without a...

Chiti, Fabrizio; Calamai, Martino; Taddei, Niccolo?; Stefani, Massimo; Ramponi, Giampietro; Dobson, Christopher M.

2002-01-01

255

Structure of the intracellular domain of the amyloid precursor protein in complex with Fe65-PTB2  

OpenAIRE

Cleavage of the amyloid precursor protein (APP) is a crucial event in Alzheimer disease pathogenesis that creates the amyloid-? peptide (A?) and liberates the carboxy-terminal APP intracellular domain (AICD) into the cytosol. The interaction of the APP C terminus with the adaptor protein Fe65 mediates APP trafficking and signalling, and is thought to regulate APP processing and A? generation. We determined the crystal structure of the AICD in complex with the C-terminal phosphotyrosine-bin...

Radzimanowski, Jens; Simon, Bernd; Sattler, Michael; Beyreuther, Konrad; Sinning, Irmgard; Wild, Klemens

2008-01-01

256

Interaction between amyloid precursor protein and presenilins in mammalian cells: Implications for the pathogenesis of Alzheimer?disease  

OpenAIRE

Mutations in the presenilin 1 (PS1) and presenilin 2 (PS2) genes increase the production of the highly amyloidogenic 42-residue form of amyloid ?-protein (A?42) in a variety of cell lines and transgenic mice. To elucidate the molecular mechanism of this effect, wild-type (wt) or mutant PS1 and PS2 genes were stably transfected into Chinese hamster ovary cells expressing endogenous or transfected ?-amyloid precursor protein (APP). By immunoprecipitation/Western blot analysis, APP was consis...

Xia, Weiming; Zhang, Jimin; Perez, Ruth; Koo, Edward H.; Selkoe, Dennis J.

1997-01-01

257

Coordinated transport of phosphorylated amyloid-? precursor protein and c-Jun NH2-terminal kinase–interacting protein-1  

OpenAIRE

The transmembrane protein amyloid-? precursor protein (APP) and the vesicle-associated protein c-Jun NH2-terminal kinase–interacting protein-1 (JIP-1) are transported into axons by kinesin-1. Both proteins may bind to kinesin-1 directly and can be transported separately. Because JIP-1 and APP can interact, kinesin-1 may recruit them as a complex, enabling their cotransport. In this study, we tested whether APP and JIP-1 are transported together or separately on different vesicles. We found...

Muresan, Zoia; Muresan, Virgil

2005-01-01

258

FE65 proteins regulate NMDA receptor activation-induced amyloid precursor protein processing.  

Science.gov (United States)

Amyloid precursor protein (APP) family members and their proteolytic products are implicated in normal nervous system function and Alzheimer's disease pathogenesis. APP processing and A? secretion are regulated by neuronal activity. Various data suggest that NMDA receptor (NMDAR) activity plays a role in both non-amyloidogenic and amyloidogenic APP processing depending on whether synaptic or extrasynaptic NMDARs are activated, respectively. The APP-interacting FE65 proteins modulate APP trafficking and processing in cell lines, but little is known about their contribution to APP trafficking and processing in neurons, either in vivo or in vitro. In this study, we examined the contribution of the FE65 protein family to APP trafficking and processing in WT and FE65/FE65L1 double knockout neurons under basal conditions and following NMDAR activation. We report that FE65 proteins facilitate neuronal A? secretion without affecting APP fast axonal transport to pre-synaptic terminals. In addition, FE65 proteins facilitate an NMDAR-dependent non-amyloidogenic APP processing pathway. Generation of high-molecular weight (HMW) species bearing an APP C-terminal epitope was also observed following NMDAR activation. These HMW species require proteasomal and calpain activities for their accumulation. Recovery of APP polypeptide fragments from electroeluted HMW species having molecular weights consistent with calpain I cleavage of APP suggests that HMW species are complexes formed from APP metabolic products. Our results indicate that the FE65 proteins contribute to physiological APP processing and accumulation of APP metabolic products resulting from NMDAR activation. PMID:21824144

Suh, Jaehong; Lyckman, Alvin; Wang, Lirong; Eckman, Elizabeth A; Guénette, Suzanne Y

2011-10-01

259

Automated solid-state NMR resonance assignment of protein microcrystals and amyloids  

Energy Technology Data Exchange (ETDEWEB)

Solid-state NMR is an emerging structure determination technique for crystalline and non-crystalline protein assemblies, e.g., amyloids. Resonance assignment constitutes the first and often very time-consuming step to a structure. We present ssFLYA, a generally applicable algorithm for automatic assignment of protein solid-state NMR spectra. Application to microcrystals of ubiquitin and the Ure2 prion C-terminal domain, as well as amyloids of HET-s(218-289) and {alpha}-synuclein yielded 88-97 % correctness for the backbone and side-chain assignments that are classified as self-consistent by the algorithm, and 77-90 % correctness if also assignments classified as tentative by the algorithm are included.

Schmidt, Elena [Goethe University Frankfurt am Main, Center for Biomolecular Magnetic Resonance, Institute of Biophysical Chemistry (Germany); Gath, Julia [ETH Zurich, Physical Chemistry (Switzerland); Habenstein, Birgit [UMR 5086 CNRS/Universite de Lyon 1, Institut de Biologie et Chimie des Proteines (France); Ravotti, Francesco; Szekely, Kathrin; Huber, Matthias [ETH Zurich, Physical Chemistry (Switzerland); Buchner, Lena [Goethe University Frankfurt am Main, Center for Biomolecular Magnetic Resonance, Institute of Biophysical Chemistry (Germany); Boeckmann, Anja, E-mail: a.bockmann@ibcp.fr [UMR 5086 CNRS/Universite de Lyon 1, Institut de Biologie et Chimie des Proteines (France); Meier, Beat H., E-mail: beme@ethz.ch [ETH Zurich, Physical Chemistry (Switzerland); Guentert, Peter, E-mail: guentert@em.uni-frankfurt.de [Goethe University Frankfurt am Main, Center for Biomolecular Magnetic Resonance, Institute of Biophysical Chemistry (Germany)

2013-07-15

260

Activity-induced dendrite and dendritic spine development in human amyloid precursor protein transgenic mice.  

Science.gov (United States)

The amyloid precursor protein is essential for proper neuronal function but an imbalance in processing or metabolism or its overexpression lead to severe malfunction of the brain. The present study focused on dendritic morphology of hippocampal neurons in mice overexpressing the wild-type human amyloid precursor protein (hAPP). In addition, we examined whether enhanced physical activity may affect hAPP-related morphological changes. Overexpression of hAPP resulted in significant enlargement of dendrites, especially within the basal dendritic field but had no effect on spine density. Enhanced physical activity only moderately potentiated hAPP induced changes in dendritic size. Physical activity dependent increases in spine density were, however, augmented by hAPP overexpression. The results suggest that enhanced levels of wild-type hAPP do not result in degenerative changes of neuronal morphology, but rather promote dendritic growth. PMID:21277971

Alpár, Alán; Ueberham, Uwe; Lendvai, Dávid; Naumann, Nicole; Rohn, Susanne; Gáti, Georgina; Arendt, Thomas; Gärtner, Ulrich

2011-04-01

261

Peptides released by physiological cleavage of semen coagulum proteins form amyloids that enhance HIV infection.  

Science.gov (United States)

Semen serves as a vehicle for HIV and promotes sexual transmission of the virus, which accounts for the majority of new HIV cases. The major component of semen is the coagulum, a viscous structure composed predominantly of spermatozoa and semenogelin proteins. Due to the activity of the semen protease PSA, the coagulum is liquefied and semenogelins are cleaved into smaller fragments. Here, we report that a subset of these semenogelin fragments form amyloid fibrils that greatly enhance HIV infection. Like SEVI, another amyloid fibril previously identified in semen, the semenogelin fibrils exhibit a cationic surface and enhance HIV virion attachment and entry. Whereas semen samples from healthy individuals greatly enhance HIV infection, semenogelin-deficient semen samples from patients with ejaculatory duct obstruction are completely deficient in enhancing activity. Semen thus harbors distinct amyloidogenic peptides derived from different precursor proteins that commonly enhance HIV infection and likely contribute to HIV transmission. PMID:22177559

Roan, Nadia R; Müller, Janis A; Liu, Haichuan; Chu, Simon; Arnold, Franziska; Stürzel, Christina M; Walther, Paul; Dong, Ming; Witkowska, H Ewa; Kirchhoff, Frank; Münch, Jan; Greene, Warner C

2011-12-15

262

Peptides Released by Physiological Cleavage of Semen Coagulum Proteins Form Amyloids that Enhance HIV Infection  

Science.gov (United States)

SUMMARY Semen serves as a vehicle for HIV and promotes sexual transmission of the virus, which accounts for the majority of new HIV cases. The major component of semen is the coagulum, a viscous structure composed predominantly of spermatozoa and semenogelin proteins. Due to the activity of the semen protease PSA, the coagulum is liquefied and semenogelins are cleaved into smaller fragments. Here, we report that a subset of these semenogelin fragments form amyloid fibrils that greatly enhance HIV infection. Like SEVI, another amyloid fibril previously identified in semen, the semenogelin fibrils exhibit a cationic surface and enhance HIV virion attachment and entry. Whereas semen samples from healthy individuals greatly enhance HIV infection, semenogelin-deficient semen samples from patients with ejaculatory duct obstruction are completely deficient in enhancing activity. Semen thus harbors distinct amyloidogenic peptides derived from different precursor proteins that commonly enhance HIV infection and likely contribute to HIV transmission. PMID:22177559

Roan, Nadia R.; Müller, Janis A.; Liu, Haichuan; Chu, Simon; Arnold, Franziska; Stürzel, Christina; Walther, Paul; Dong, Ming; Witkowska, H. Ewa; Kirchhoff, Frank; Münch, Jan; Greene, Warner C.

2011-01-01

263

A comparison of immunohistochemistry and mass spectrometry for determining the amyloid fibril protein from formalin-fixed biopsy tissue.  

Science.gov (United States)

Amyloidosis is caused by deposition in tissues of abnormal protein in a characteristic fibrillar form. There are many types of amyloidosis, classified according to the soluble protein precursor from which the amyloid fibrils are derived. Accurate identification of amyloid type is critical in every case since therapy for systemic amyloidosis is type specific. In ?20-25% cases, however, immunohistochemistry (IHC) fails to prove the amyloid type and further tests are required. Laser microdissection and mass spectrometry (LDMS) is a powerful tool for identifying proteins from formalin-fixed paraffin-embedded tissues. We undertook a blinded comparison of IHC, performed at the UK National Amyloidosis Centre, and LDMS, performed at the Mayo Clinic, in 142 consecutive biopsy specimens from 38 different tissue types. There was 100% concordance between positive IHC and LDMS, and the latter increased diagnostic accuracy from 76% to 94%. LDMS in expert hands is a valuable tool for amyloid diagnosis. PMID:25637636

Gilbertson, Janet A; Theis, Jason D; Vrana, Julie A; Lachmann, Helen; Wechalekar, Ashutosh; Whelan, Carol; Hawkins, Philip N; Dogan, Ahmet; Gillmore, Julian D

2015-04-01

264

Hypersensitivity to seizures in beta-amyloid precursor protein deficient mice  

OpenAIRE

Secreted forms of the ?-amyloid precursor protein (?-APP) have neuroprotective properties in vitro and may be involved in the containment of neuronal excitation. To test whether loss of secreted forms of ?-APP (sAPPs) may enhance excitotoxic responses, we injected mice homozygous for a targeted mutation of the ?-APP gene (?-APP?/?) intraperitoneally with kainic acid. We found that in these mice, kainic acid induced seizures initiated earlier, and acute mortality was enhanced compared...

Steinbach, Joachim P.; Mu?ller, Ulrike; Leist, Marcel; Li, Zhi-wei; Nicotera, Pierluigi; Aguzzi, Adriano

1998-01-01

265

Exploring the Folding Pathways of Proteins through Energy Landscape Sampling: Application to Alzheimer's ?-Amyloid Peptide  

Directory of Open Access Journals (Sweden)

Full Text Available The determination of the folding mechanisms of proteins is critical to understand the topological change that can propagate Alzheimer's and prion diseases. The associated folding time scale generally precludes the use of molecular dynamics simulations. Here we present the details of the activation-relaxation simulations using the generic OPEP energy model. We illustrate the strengths of our approach by studying the folding of a dimer of the Alzheimer's ?-amyloid peptide.

Sebastien Santini

2003-09-01

266

Enhanced pathologic properties of Dutch-type mutant amyloid beta-protein.  

OpenAIRE

Cerebrovascular amyloid beta-protein (Abeta) deposition is a pathological feature of several related disorders including Alzheimer disease and hereditary cerebral hemorrhage with amyloidosis Dutch-type (HCHWA-D). HCHWA-D is caused by a point mutation in the gene that encodes the Abeta precursor and results in a Glu --> Gln substitution at position 22 of Abeta. In comparison to Alzheimer disease, the cerebrovascular Abeta deposition in HCHWA-D is generally more severe, often resulting in intra...

Davis, J.; Nostrand, W. E.

1996-01-01

267

Peptides Released by Physiological Cleavage of Semen Coagulum Proteins Form Amyloids that Enhance HIV Infection  

OpenAIRE

Semen serves as a vehicle for HIV and promotes sexual transmission of the virus, which accounts for the majority of new HIV cases. The major component of semen is the coagulum, a viscous structure composed predominantly of spermatozoa and semenogelin proteins. Due to the activity of the semen protease PSA, the coagulum is liquefied and semenogelins are cleaved into smaller fragments. Here, we report that a subset of these semenogelin fragments form amyloid fibrils that greatly enhance HIV inf...

Roan, Nadia R.; Mu?ller, Janis A.; Liu, Haichuan; Chu, Simon; Arnold, Franziska; Stu?rzel, Christina; Walther, Paul; Dong, Ming; Witkowska, H. Ewa; Kirchhoff, Frank; Mu?nch, Jan; Greene, Warner C.

2011-01-01

268

Regulated intramembrane proteolysis of amyloid precursor protein and regulation of expression of putative target genes  

OpenAIRE

?-Secretase-dependent regulated intramembrane proteolysis of amyloid precursor protein (APP) releases the APP intracellular domain (AICD). The question of whether this domain, like the Notch intracellular domain, is involved in nuclear signalling is highly controversial. Although some reports suggest that AICD regulates the expression of KAI1, glycogen synthase kinase-3?, Neprilysin and APP, we found no consistent effects of ?-secretase inhibitors or of genetic deficiencies in the ?-secre...

He?bert, Se?bastien S.; Serneels, Lutgarde; Tolia, Alexandra; Craessaerts, Katleen; Derks, Carmen; Filippov, Mikhail A.; Mu?ller, Ulrike; Strooper, Bart

2006-01-01

269

Soluble amyloid precursor protein ? as blood-based biomarker of Alzheimer's disease  

OpenAIRE

The aim of this study was to explore concentrations differences of soluble amyloid precursor protein (sAPP) ? and ? in blood plasma in patients with probable Alzheimer's disease (AD) and cognitively healthy age-matched control subjects, as well as patients with behavioural variant frontotemporal dementia (bvFTD). Concentrations of sAPP? and ? were measured using enzyme-linked immunosorbent assay technology in 80 patients with probable AD, 37 age-matched control subjects and 14 patients wi...

Perneczky, R.; Guo, L-h; Kagerbauer, S. M.; Werle, L.; Kurz, A.; Martin, J.; Alexopoulos, P.

2013-01-01

270

Amyloid beta precursor protein and ubiquitin epitopes in human and experimental dystrophic axons. Ultrastructural localization.  

OpenAIRE

Dystrophic axons (DA) represent a major pathological feature of several neurodegenerative disorders, including infantile neuroaxonal dystrophy (INAD) and Alzheimer disease. We have previously presented evidence that amyloid beta precursor protein (BPP) and ubiquitin (Ub) are present in DA of different origin. We have now characterized the immunoreactivity of DA experimentally induced in rat by the administration of parabromophenylacetylurea (BPAU) and examined the subcellular localization of ...

Bacci, B.; Cochran, E.; Nunzi, M. G.; Izeki, E.; Mizutani, T.; Patton, A.; Hite, S.; Sayre, L. M.; Autilio-gambetti, L.; Gambetti, P.

1994-01-01

271

Regulation of the Proteolytic Processing and Function of Amyloid Precursor Protein by Candidate Ligands  

OpenAIRE

Despite intense interest in the proteolysis of Amyloid Precursor Protein (APP) in Alzheimer’s disease (AD), how the normal processing and function of this type I receptor-like glycoprotein is regulated remains ill-defined. APP is reported to function in neurodevelopment, including migration of neuronal precursor cells into the cortical plate. In recent years, several candidate ligands for APP, including F-spondin, Reelin, \\(\\beta1\\) Integrin, Contactins, and Lingo-1 have been reported. Howe...

Rice, Heather Caroline

2013-01-01

272

Nonsteroidal Anti-Inflammatory Drugs and Ectodomain Shedding of the Amyloid Precursor Protein  

OpenAIRE

Background: Epidemiological studies have suggested that long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs) is associated with a reduced incidence of Alzheimer's disease (AD). Several mechanisms have been proposed to explain these findings including increased shedding of the soluble ectodomain of the amyloid precursor protein (sAPP), which functions as a neurotrophic and neuroprotective factor in vitro and in vivo. Objective: To clarify whether NSAIDs consistently stimulate sAPP se...

Leuchtenberger, Stefanie; Maler, Juan; Czirr, Eva; Ness, Julia; Lichtenthaler, Stefan F.; Esselmann, Hermann; Pietrzik, Claus U.; Wiltfang, Jens; Weggen, Sascha

2009-01-01

273

Amyloid Precursor Protein Is an Autonomous Growth Cone Adhesion Molecule Engaged in Contact Guidance  

OpenAIRE

Amyloid precursor protein (APP), a transmembrane glycoprotein, is well known for its involvement in the pathogenesis of Alzheimer disease of the aging brain, but its normal function is unclear. APP is a prominent component of the adult as well as the developing brain. It is enriched in axonal growth cones (GCs) and has been implicated in cell adhesion and motility. We tested the hypothesis that APP is an extracellular matrix adhesion molecule in experiments that isolated the function of APP f...

Sosa, Lucas J.; Bergman, Jared; Estrada-bernal, Adriana; Glorioso, Thomas J.; Kittelson, John M.; Pfenninger, Karl H.

2013-01-01

274

The Amyloid-? Precursor Protein Is Phosphorylated via Distinct Pathways during Differentiation, Mitosis, Stress, and Degeneration  

OpenAIRE

Phosphorylation of amyloid-? precursor protein (APP) at Thr668 is a normal process linked to neurite extension and anterograde transport of vesicular cargo. By contrast, increased phosphorylation of APP is a pathological trait of Alzheimer's disease. APP is overexpressed in Down's syndrome, a condition that occasionally leads to increased APP phosphorylation, in cultured cells. Whether phosphorylation of APP in normal versus high APP conditions occurs by similar or distinct signaling pathway...

Muresan, Zoia; Muresan, Virgil

2007-01-01

275

UV Irradiation Accelerates Amyloid Precursor Protein (APP) Processing and Disrupts APP Axonal Transport  

OpenAIRE

Overexpression and/or abnormal cleavage of amyloid precursor protein (APP) are linked to Alzheimer's disease (AD) development and progression. However, the molecular mechanisms regulating cellular levels of APP or its processing, and the physiological and pathological consequences of altered processing are not well understood. Here, using mouse and human cells, we found that neuronal damage induced by UV irradiation leads to specific APP, APLP1, and APLP2 decline by accelerating their secreta...

Almenar-queralt, Angels; Falzone, Tomas L.; Shen, Zhouxin; Lillo, Concepcion; Killian, Rhiannon L.; Arreola, Angela S.; Niederst, Emily D.; Ng, Kheng S.; Kim, Sonia N.; Briggs, Steven P.; Williams, David S.; Goldstein, Lawrence S. B.

2014-01-01

276

Amyloid ?-protein (A?) assembly: A?40 and A?42 oligomerize through distinct pathways  

OpenAIRE

Amyloid ?-protein (A?) is linked to neuronal injury and death in Alzheimer's disease (AD). Of particular relevance for elucidating the role of A? in AD is new evidence that oligomeric forms of A? are potent neurotoxins that play a major role in neurodegeneration and the strong association of the 42-residue form of A?, A?42, with the disease. Detailed knowledge of the structure and assembly dynamics of A? thus is important for the development of properly targeted AD therapeutics. Recent...

Bitan, Gal; Kirkitadze, Marina D.; Lomakin, Aleksey; Vollers, Sabrina S.; Benedek, George B.; Teplow, David B.

2002-01-01

277

Amyloid Precursor Protein (APP) Affects Global Protein Synthesis in Dividing Human Cells.  

Science.gov (United States)

Hypoxic non-small cell lung cancer (NSCLC) is dependent on Notch-1 signaling for survival. Targeting Notch-1 by means of ?-secretase inhibitors (GSI) proved effective in killing hypoxic NSCLC. Post-mortem analysis of GSI-treated, NSCLC-burdened mice suggested enhanced phosphorylation of 4E-BP1 at threonines 37/46 in hypoxic tumor tissues. In vitro dissection of this phenomenon revealed that Amyloid Precursor Protein (APP) inhibition was responsible for a non-canonical 4E-BP1 phosphorylation pattern rearrangement-a process, in part, mediated by APP regulation of the pseudophosphatase Styx. Upon APP depletion we observed modifications of eIF-4F composition indicating increased recruitment of eIF-4A to the mRNA cap. This phenomenon was supported by the observation that cells with depleted APP were partially resistant to silvestrol, an antibiotic that interferes with eIF-4A assembly into eIF-4F complexes. APP downregulation in dividing human cells increased the rate of global protein synthesis, both cap- and IRES-dependent. Such an increase seemed independent of mTOR inhibition. After administration of Torin-1, APP downregulation and Mechanistic Target of Rapamycin Complex 1 (mTORC-1) inhibition affected 4E-BP1 phosphorylation and global protein synthesis in opposite fashions. Additional investigations indicated that APP operates independently of mTORC-1. Key phenomena described in this study were reversed by overexpression of the APP C-terminal domain. The presented data suggest that APP may be a novel regulator of protein synthesis in dividing human cells, both cancerous and primary. Furthermore, APP appears to affect translation initiation using mechanisms seemingly dissimilar to mTORC-1 regulation of cap-dependent protein synthesis. J. Cell. Physiol. 230: 1064-1074, 2015. © 2014 Wiley Periodicals, Inc., A Wiley Company. PMID:25283437

Sobol, Anna; Galluzzo, Paola; Liang, Shuang; Rambo, Brittany; Skucha, Sylvia; Weber, Megan J; Alani, Sara; Bocchetta, Maurizio

2015-05-01

278

Amyloid aggregates of the HET-s prion protein are infectious  

OpenAIRE

The [Het-s] infectious element of the filamentous fungus Podospora anserina is a prion. We have recently reported that recombinant HET-s protein aggregates in vitro into amyloid fibers. In vivo, the protein aggregates specifically in the [Het-s] prion strains. Here, we show that biolistic introduction of aggregated recombinant HET-s protein into fungal cells induces emergence of the [Het-s] prion with a high frequency. Thus, we demonstrate that prion infectivity can be created de novo, in vit...

Maddelein, Marie-lise; Dos Reis, Suzana; Duvezin-caubet, Ste?phane; Coulary-salin, Be?ne?dicte; Saupe, Sven J.

2002-01-01

279

A Role for the High-Density Lipoprotein Receptor SR-B1 in Synovial Inflammation via Serum Amyloid-A  

OpenAIRE

Acute phase apoprotein Serum Amyloid A (A-SAA), which is strongly expressed in rheumatoid arthritis synovial membrane (RA SM), induces angiogenesis, adhesion molecule expression, and matrix metalloproteinase production through the G-coupled receptor FPRL-1. Here we report alternative signaling through the high-density lipoprotein receptor scavenger receptor-class B type 1 (SR-B1). Quantitative expression/localization of SR-B1 in RA SM, RA fibroblast-like cells (FLCs), and microvascular endoth...

Mullan, Ronan Hugh; Mccormick, Jennifer; Connolly, Mary; Bresnihan, Barry; Veale, Douglas James; Fearon, Ursula

2010-01-01

280

In equine grass sickness, serum amyloid A and fibrinogen are elevated, and can aid differential diagnosis from non-inflammatory causes of colic.  

Science.gov (United States)

Equine grass sickness (EGS) is a debilitating and often fatal neurodegenerative disease. A presumptive diagnosis of EGS may be made on the basis of clinical signs and subjective ancillary tests, but a definitive antemortem diagnosis can only be made following histopathological examination of intestinal biopsies. It has previously been reported that horses with EGS may show clinical and clinicopathological signs of systemic inflammation. The objective of this study was to (a) quantify acute inflammatory markers in blood samples collected from acute, subacute and chronic EGS cases, and (b) compare them with (i) clinically normal horses co-grazing with acute EGS cases (co-grazers), (ii) horses with other causes of colic and (iii) healthy horses. Serum amyloid A (SAA), serum activin A and plasma fibrinogen were quantified. There were marked increases in SAA and fibrinogen in EGS cases compared with healthy horses, co-grazers and non-inflammatory colic cases. The concentrations of SAA and fibrinogen in EGS cases were not significantly different from inflammatory colic cases. When concentrations of SAA, fibrinogen and activin A in each EGS subgroup were compared, no significant differences were detected. Activin A concentrations were significantly elevated in EGS cases and co-grazing horses; this could reflect the presence of subclinical disease in some horses that do not develop clinical signs of EGS, and suggests widespread exposure to the aetiological agent. When faced with sparse antemortem diagnostic techniques, identification of marked increases in acute phase protein concentrations may help to differentiate EGS from other causes of abdominal pain, such as intestinal obstructions; however, there could be diagnostic difficulty in differentiating other inflammatory abdominal conditions, such as peritonitis or enteritis. PMID:23428423

Copas, V E N; Durham, A E; Stratford, C H; McGorum, B C; Waggett, B; Pirie, R S

2013-04-13

281

Carboxyl-terminal fragments of beta-amyloid precursor protein bind to microtubules and the associated protein tau.  

Science.gov (United States)

Alzheimer's disease is a neurodegenerative disorder characterized by protein depositions in intracellular and extracellular spaces in the brain. The intraneuronal deposits are formed by neurofibrillary tangles composed mainly of abnormally phosphorylated tau, a microtubule-associated protein, whereas the major constituent of the amyloid deposited extracellularly in the brain parenchyma and vessel walls is amyloid beta-protein (A beta). The proteolytic processing of the beta-amyloid precursor protein (beta PP) results in the generation of a complex set of carboxyl-terminal peptides that contain A beta. In this study, we have used fusion proteins containing carboxyl-terminal fragments of beta PP to investigate the association of beta PP with cellular components. We demonstrate that specific domains within the carboxyl end of beta PP contain binding sites for cytoskeletal components; one, within residues 1 to 28 of A beta, binds directly to tubulin, and the second one, within sequences carboxyl-terminal to A beta, binds tau and tubulin. We propose that the two neuropathological hallmarks of Alzheimer's disease, A beta deposition and neurofibrillary tangles, represent the residual of a disrupted beta PP-tubulin-tau complex. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:9212751

Islam, K.; Levy, E.

1997-01-01

282

Serum-protein changes in lambs given Dictyocaulus filaria vaccine  

International Nuclear Information System (INIS)

The serum-protein changes in lambs given a double dose of irradiated vaccine (40 and 50 kR) were compared with those of non-vaccinated lambs in all the groups. ?- and ?-globulins were similar but ?-globulins were higher for some weeks in animals given vaccination. Values of serum protein could not be correlated with the vaccine or with the immune status of the animals. In all the animals, the albumin/globulin ratio remained generally well below 1. (auth.)

283

TSH binding proteins in rat and human serum  

International Nuclear Information System (INIS)

When serum of hypothyroid rats was fractionated on a Sephadex G-100 column, most of the immunoreactive TSH was found as a front running peak, together with the high molecular weight serum proteins. Similarly, a rTSH preparation (10 mU), chromatographed in the presence of 1 ml of normal rat serum also migrated at the front, however, when a high load of TSH (4.4 U) was added to 1 ml of serum, two immunoreactive peaks were found, suggesting the saturation of the front running fraction. Immunoelectrophoresis and autoradiography of rat or human sera containing the respective 125I-labelled TSHs showed binding of the labelled TSH to IgG, alpha-2-macroglobulin, and to a third unidentified protein, migrating near the albumin line. In order to determine if the bound TSH is biologically active, the high molecular weight protein fraction was separated from hypothyroid rat serum by 45% ammonium sulphate precipitation. Immunoreactivity was determined by RIA and the biological activity was determined, in vitro, by the stimulation of 99Tc uptake by FRTL-5 cells. The 45% ammonium sulphate precipitate contained almost all of the immunoreactivity and the bioactivity of the TSH of whole serum. These results indicate that: a) The endogenous circulating TSH in the hypothyroid rat exists mainly in a protein-bound form and this protein-bound TSH contains most of the hormonal bioactivity of the serum. b) Exogenous TSH binds to serum proteins in euthyroid and hypothyroid rum proteins in euthyroid and hypothyroid rats and in humans. There are three protein fractions in these sera that bind TSH, one of which is an immunoglobulin. The occurence of TSH binding immunoglobulins may involve autoimmune mechanisms. (author)

284

Serum Copper and Plasma Protein Status in Normal Pregnancy  

OpenAIRE

AbstractBackground: Gradual alteration of serum copper and some plasma protein levels may occur with advancement of pregnancy, which is associated with increased maternal and infant morbidity and mortality.Objective: To observe serum copper and plasma protein levels in normal pregnant women of different trimesters in order to find out their nutritional status.Methods: This cross sectional study was carried out in the Department of Physiology, Sir Salimullah Medical College (SSMC), Dhaka, betw...

Nushrat Noor, Nasim Jahan

2012-01-01

285

Powerful beneficial effects of benfotiamine on cognitive impairment and beta-amyloid deposition in amyloid precursor protein/presenilin-1 transgenic mice.  

Science.gov (United States)

Reduction of glucose metabolism in brain is one of the main features of Alzheimer's disease. Thiamine (vitamin B1)-dependent processes are critical in glucose metabolism and have been found to be impaired in brains from patients with Alzheimer's disease. However, thiamine treatment exerts little beneficial effect in these patients. Here, we tested the effect of benfotiamine, a thiamine derivative with better bioavailability than thiamine, on cognitive impairment and pathology alterations in a mouse model of Alzheimer's disease, the amyloid precursor protein/presenilin-1 transgenic mouse. We show that after a chronic 8 week treatment, benfotiamine dose-dependently enhanced the spatial memory of amyloid precursor protein/presenilin-1 mice in the Morris water maze test. Furthermore, benfotiamine effectively reduced both amyloid plaque numbers and phosphorylated tau levels in cortical areas of the transgenic mice brains. Unexpectedly, these effects were not mimicked by another lipophilic thiamine derivative, fursultiamine, although both benfotiamine and fursultiamine were effective in increasing the levels of free thiamine in the brain. Most notably, benfotiamine, but not fursultiamine, significantly elevated the phosphorylation level of glycogen synthase kinase-3alpha and -3beta, and reduced their enzymatic activities in the amyloid precursor protein/presenilin-1 transgenic brain. Therefore, in the animal Alzheimer's disease model, benfotiamine appears to improve the cognitive function and reduce amyloid deposition via thiamine-independent mechanisms, which are likely to include the suppression of glycogen synthase kinase-3 activities. These results suggest that, unlike many other thiamine-related drugs, benfotiamine may be beneficial for clinical Alzheimer's disease treatment. PMID:20385653

Pan, Xiaoli; Gong, Neng; Zhao, Jing; Yu, Zhe; Gu, Fenghua; Chen, Jia; Sun, Xiaojing; Zhao, Lei; Yu, Meijing; Xu, Zhiru; Dong, Wenxin; Qin, Yan; Fei, Guoqiang; Zhong, Chunjiu; Xu, Tian-Le

2010-05-01

286

Specific Changes of Serum Proteins in Parkinson's Disease Patients  

OpenAIRE

The aim of this study is to identify and validate protein change in the serum from PD patients. We used serum samples from 21 PD patients and 20 age-matched normal people as control to conduct a comparative proteomic study. We performed 2-DE and analyzed the differentially expressed protein spots by LC-MS/MS. In PD group 13 spots were shown to be differentially expressed compared to control group. They were identified as 6 proteins. Among these, 3 proteins were confirmed by Western blot analy...

Lu, Wenwen; Wan, Xinhua; Liu, Bin; Rong, Xianfang; Zhu, Lei; Li, Pingping; Li, Jiang; Wang, Ling; Cui, Liying; Wang, Xiaoliang

2014-01-01

287

TSH binding proteins in rat and human serum  

Energy Technology Data Exchange (ETDEWEB)

When serum of hypothyroid rats was fractionated on a Sephadex G-100 column, most of the immunoreactive TSH was found as a front running peak, together with the high molecular weight serum proteins. Similarly, a rTSH preparation (10 mU), chromatographed in the presence of 1 ml of normal rat serum also migrated at the front, however, when a high load of TSH (4.4 U) was added to 1 ml of serum, two immunoreactive peaks were found, suggesting the saturation of the front running fraction. Immunoelectrophoresis and autoradiography of rat or human sera containing the respective /sup 125/I-labelled TSHs showed binding of the labelled TSH to IgG, alpha-2-macroglobulin, and to a third unidentified protein, migrating near the albumin line. In order to determine if the bound TSH is biologically active, the high molecular weight protein fraction was separated from hypothyroid rat serum by 45% ammonium sulphate precipitation. Immunoreactivity was determined by RIA and the biological activity was determined, in vitro, by the stimulation of /sup 99/Tc uptake by FRTL-5 cells. The 45% ammonium sulphate precipitate contained almost all of the immunoreactivity and the bioactivity of the TSH of whole serum. These results indicate that: a) The endogenous circulating TSH in the hypothyroid rat exists mainly in a protein-bound form and this protein-bound TSH contains most of the hormonal bioactivity of the serum. b) Exogenous TSH binds to serum proteins in euthyroid and hypothyroid rats and in humans. There are three protein fractions in these sera that bind TSH, one of which is an immunoglobulin. The occurence of TSH binding immunoglobulins may involve autoimmune mechanisms.

Spira, O.; Gafni, M.; Ben-David, C.; Gross, J.; Gordon, A.

1987-01-01

288

Strong transthyretin immunostaining: potential pitfall in cardiac amyloid typing.  

Science.gov (United States)

Although systemic amyloidosis commonly presents with renal disease, cardiac involvement usually determines the patient's prognosis. Cardiac involvement is seen in light chain amyloid and transthyretin amyloidosis. Distinguishing between these two is critical because prognosis and treatment differ. Our study demonstrates the unreliability of transthyretin immunostaining in subtyping cardiac amyloid. Between January 2003 and August 2010, we retrieved 229 native endomyocardial biopsies, of which 24 had amyloid. Immunohistochemistry for ?, ?, transthyretin, and serum amyloid A protein was performed on formalin-fixed, paraffin-embedded sections. Staining was graded as weak (trace to 1+) or strong (2 to 3+). Mass spectrometry (MS)-based proteomic typing of microdissected amyloid material was performed on selected cases. Fifteen patients had monoclonal gammopathy/plasma cell dyscrasia with cardiac amyloid. Eight of them (53%) showed strong transthyretin staining in the cardiac amyloid deposits. MS was performed in 5 of these 8 biopsies, and all 5 biopsies revealed light chain amyloid-type amyloid. Two of these 5 light chain amyloid biopsies did not even have concomitant strong staining for the appropriate light chain. Among the 15 cases with plasma cell dyscrasia, only 7 biopsies showed strong staining for the corresponding monoclonal light chain. Strong, false-positive immunostaining for transthyretin in cardiac amyloid is a potential pitfall, augmented by the frequent lack of staining for immunoglobulin light chains. Therefore, the presence of amyloid in the cardiac biopsy should prompt a search for plasma cell dyscrasia irrespective of transthyretin staining. Confirmation with MS should be sought, particularly if there is any discrepancy between ?/? staining and serum immunofixation results. PMID:21945954

Satoskar, Anjali A; Efebera, Yvonne; Hasan, Ayesha; Brodsky, Sergey; Nadasdy, Gyongyi; Dogan, Ahmet; Nadasdy, Tibor

2011-11-01

289

Serum amyloid A stimulates macrophage foam cell formation via lectin-like oxidized low-density lipoprotein receptor 1 upregulation  

Energy Technology Data Exchange (ETDEWEB)

Highlights: ? SAA induced macrophage foam cell formation. ? SAA stimulated upregulation of lectin-like oxidized low-density lipoprotein receptor 1 (LOX1). ? SAA-induced LOX1 expression and foam cell formation is mediated by JNK/NF-?B signaling. ? HDL-conjugated SAA also stimulates foam cell formation via LOX1 upregulation. ? The finding reveals a novel mechanism of action of SAA in the pathogenesis of atherosclerosis. -- Abstract: Elevated levels of serum amyloid A (SAA) is a risk factor for cardiovascular diseases, however, the role of SAA in the pathophysiology of atherosclerosis remains unclear. Here we show that SAA induced macrophage foam cell formation. SAA-stimulated foam cell formation was mediated by c-jun N-terminal kinase (JNK) signaling. Moreover, both SAA and SAA-conjugated high density lipoprotein stimulated the expression of the important scavenger receptor lectin-like oxidized low-density lipoprotein receptor 1 (LOX1) via nuclear factor-?B (NF-?B). A LOX1 antagonist carrageenan significantly blocked SAA-induced foam cell formation, indicating that SAA promotes foam cell formation via LOX1 expression. Our findings therefore suggest that SAA stimulates foam cell formation via LOX1 induction, and thus likely contributes to atherogenesis.

Lee, Ha Young, E-mail: hayoung@skku.edu [Department of Biological Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Mitochondria Hub Regulation Center, Dong-A University, Busan 602-714 (Korea, Republic of); Kim, Sang Doo [Department of Biological Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Baek, Suk-Hwan [Department of Biochemistry and Molecular Biology, College of Medicine, Yeungnam University, Daegu 705-717 (Korea, Republic of); Choi, Joon Hyuk [Department of Pathology, College of Medicine, Yeungnam University, Daegu 705-717 (Korea, Republic of); Cho, Kyung-Hyun [School of Biotechnology, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Zabel, Brian A. [Palo Alto Institute for Research and Education, Veterans Affairs Hospital, Palo Alto, CA 94304 (United States); Bae, Yoe-Sik, E-mail: yoesik@skku.edu [Department of Biological Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Mitochondria Hub Regulation Center, Dong-A University, Busan 602-714 (Korea, Republic of); Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul 135-710 (Korea, Republic of)

2013-03-29

290

Serum amyloid A stimulates macrophage foam cell formation via lectin-like oxidized low-density lipoprotein receptor 1 upregulation  

International Nuclear Information System (INIS)

Highlights: ? SAA induced macrophage foam cell formation. ? SAA stimulated upregulation of lectin-like oxidized low-density lipoprotein receptor 1 (LOX1). ? SAA-induced LOX1 expression and foam cell formation is mediated by JNK/NF-?B signaling. ? HDL-conjugated SAA also stimulates foam cell formation via LOX1 upregulation. ? The finding reveals a novel mechanism of action of SAA in the pathogenesis of atherosclerosis. -- Abstract: Elevated levels of serum amyloid A (SAA) is a risk factor for cardiovascular diseases, however, the role of SAA in the pathophysiology of atherosclerosis remains unclear. Here we show that SAA induced macrophage foam cell formation. SAA-stimulated foam cell formation was mediated by c-jun N-terminal kinase (JNK) signaling. Moreover, both SAA and SAA-conjugated high density lipoprotein stimulated the expression of the important scavenger receptor lectin-like oxidized low-density lipoprotein receptor 1 (LOX1) via nuclear factor-?B (NF-?B). A LOX1 antagonist carrageenan significantly blocked SAA-induced foam cell formation, indicating that SAA promotes foam cell formation via LOX1 expression. Our findings therefore suggest that SAA stimulates foam cell formation via LOX1 induction, and thus likely contributes to atherogenesis

291

The predominant form of the amyloid beta-protein precursor in human brain is protease nexin 2.  

OpenAIRE

The amyloid beta protein and the amyloid beta-protein precursor (APP) are major constituents of senile plaques and cerebrovascular deposits in patients with Alzheimer disease and Down syndrome. Most human tissues contain mRNA that encodes forms of APP that contain the Kunitz protease inhibitor (KPI+) domain. A major 120-kDa protein corresponding to this KPI+ mRNA is also found in these tissues. This protein is identical to the protease inhibitor protease nexin 2. Brain contains an additional ...

Nostrand, W. E.; Farrow, J. S.; Wagner, S. L.; Bhasin, R.; Goldgaber, D.; Cotman, C. W.; Cunningham, D. D.

1991-01-01

292

Synaptic NMDA receptor activation stimulates alpha-secretase amyloid precursor protein processing and inhibits amyloid-beta production.  

Science.gov (United States)

Altered amyloid precursor protein (APP) processing leading to increased production and oligomerization of Abeta may contribute to Alzheimer's disease (AD). Understanding how APP processing is regulated under physiological conditions may provide new insights into AD pathogenesis. Recent reports demonstrate that excitatory neural activity regulates APP metabolism and Abeta levels, although understanding of the molecular mechanisms involved is incomplete. We have investigated whether NMDA receptor activity regulates APP metabolism in primary cultured cortical neurons. We report that a pool of APP is localized to the postsynaptic compartment in cortical neurons and observed partial overlap of APP with both NR1 and PSD-95. NMDA receptor stimulation increased nonamyloidogenic alpha-secretase-mediated APP processing, as measured by a 2.5-fold increase in cellular alpha-C-terminal fragment (C83) levels after glutamate or NMDA treatment. This increase was blocked by the NMDA receptor antagonists d-AP5 and MK801 but not by the AMPA receptor antagonist CNQX or the L-type calcium channel blocker nifedipine, was prevented by chelation of extracellular calcium, and was blocked by the alpha-secretase inhibitor TAPI-1. Cotreatment of cortical neurons with bicuculline and 4-AP, which stimulates glutamate release and activates synaptic NMDA receptors, evoked an MK801-sensitive increase in C83 levels. Furthermore, NMDA receptor stimulation caused a twofold increase in the amount of soluble APP detected in the neuronal culture medium. Finally, NMDA receptor activity inhibited both Abeta1-40 release and Gal4-dependent luciferase activity induced by beta-gamma-secretase-mediated cleavage of an APP-Gal4 fusion protein. Altogether, these data suggest that calcium influx through synaptic NMDA receptors promotes nonamyloidogenic alpha-secretase-mediated APP processing. PMID:19357271

Hoey, Sarah E; Williams, Robert J; Perkinton, Michael S

2009-04-01

293

Alzheimer's amyloid precursor protein-positive degenerative neurites exist even within kuru plaques not specific to Alzheimer's disease.  

OpenAIRE

To clarify the relationship between amyloid formation and amyloid precursor protein (APP), the brain sections from eight patients with Alzheimer's disease (AD) and four with Gerstmann-Sträussler Syndrome (GSS) were investigated immunohistochemically by the double-immunostaining method. In AD, most APP-positive senile plaques belong to classical plaques or primitive plaques, whereas in diffuse plaques, APP-positive neuritic components are rarely observed. The authors documented that anti-APP-...

Ohgami, T.; Kitamoto, T.; Weidmann, A.; Beyreuther, K.; Tateishi, J.

1991-01-01

294

Studies on the gamma-secretase complex and processing of the Alzheimer's disease-associated amyloid precursor protein  

OpenAIRE

Alzheimer s disease (AD) is a devastating neurodegenerative disorder that causes the most common form of dementia. Pathological lesions, such as plaques consisting of the amyloid beta-peptide (Ab), are found in the brains of AD patients. Ab is produced by sequential cleavages of the amyloid precursor protein (APP) by beta- and gamma-secretase. Concomitant with gamma-cleavage, another cleavage, termed epsilon-cleavage, occurs seven to nine residues C-terminal of the gamma-sit...

Bergman, Anna

2004-01-01

295

BRI3 Inhibits Amyloid Precursor Protein Processing in a Mechanistically Distinct Manner from Its Homologue Dementia Gene BRI2*  

OpenAIRE

Alzheimer disease (AD) is characterized by senile plaques, which are mainly composed of ? amyloid (A?) peptides. A? is cleaved off from amyloid precursor protein (APP) with consecutive proteolytic processing: ?-secretase, followed by ?-secretase. Here, we show that BRI3, a member of the BRI gene family that includes the familial British and Danish dementia gene BRI2, interacts with APP and serves as an endogenous negative regulator of A? production. BRI3 colocalizes with APP along neuri...

Matsuda, Shuji; Matsuda, Yukiko; D Adamio, Luciano

2009-01-01

296

Soluble amyloid precursor protein (APP) regulates transthyretin and Klotho gene expression without rescuing the essential function of APP  

OpenAIRE

Amyloidogenic processing of the amyloid precursor protein (APP) generates a large secreted ectodomain fragment (APPs?), ?-amyloid (A?) peptides, and an APP intracellular domain (AICD). Whereas A? is viewed as critical for Alzheimer's disease pathogenesis, the role of other APP processing products remains enigmatic. Of interest, the AICD has been implicated in transcriptional regulation, and N-terminal cleavage of APPs? has been suggested to produce an active fragment that may mediate axo...

Li, Hongmei; Wang, Baiping; Wang, Zilai; Guo, Qinxi; Tabuchi, Katsuhiko; Hammer, Robert E.; Su?dhof, Thomas C.; Zheng, Hui

2010-01-01

297

Focally Elevated Creatine Detected in Amyloid Precursor Protein (APP) Transgenic Mice and Alzheimer Disease Brain Tissue  

Energy Technology Data Exchange (ETDEWEB)

The creatine/phosphocreatine system, regulated by creatine kinase, plays an important role in maintaining energy balance in the brain. Energy metabolism and the function of creatine kinase are known to be affected in Alzheimer diseased brain and in cells exposed to the {beta}-amyloid peptide. We used infrared microspectroscopy to examine hippocampal, cortical, and caudal tissue from 21-89-week-old transgenic mice expressing doubly mutant (K670N/M671L and V717F) amyloid precursor protein and displaying robust pathology from an early age. Microcrystalline deposits of creatine, suggestive of perturbed energetic status, were detected by infrared microspectroscopy in all animals with advanced plaque pathology. Relatively large creatine deposits were also found in hippocampal sections from post-mortem Alzheimer diseased human brain, compared with hippocampus from non-demented brain. We therefore speculate that this molecule is a marker of the disease process.

Gallant,M.; Rak, M.; Szeghalmi, A.; Del Bigio, M.; Westaway, D.; Yang, J.; Julian, R.; Gough, K.

2006-01-01

298

Assessing novel prognostic serum biomarkers in advanced pancreatic cancer: the role of CYFRA 21-1, serum amyloid A, haptoglobin, and 25-OH vitamin D3.  

Science.gov (United States)

The present prospective single-center study investigated the prognostic role of novel serum biomarkers in advanced pancreatic cancer (PC). Patients (pts) with locally advanced or metastatic PC treated with first-line palliative chemotherapy were included. Among others, the serum markers CYFRA 21-1, haptoglobin, serum-amyloid A (SAA), and 25-OH vitamin D3 were determined at baseline and categorized by pre-defined cut-offs [median values (MV), upper limits of normal (ULN), lower limits of normal (LLN), or the natural logarithm (ln)] and correlated with overall survival (OS). Among the 59 pts included, pre-treatment CYFRA 21-1 levels showed a strong correlation with OS independent of the applied cut-off (MV 4.9 ng/ml-14.2 vs. 4.2 months, HR 0.18, p?=?0.001; ULN 3.3 ng/ml-14.2 vs. 4.4 months, HR 0.28, p?=?0.003; [ln] CYFRA 21-1-HR 0.77, p?=?0.013). Lower values of haptoglobin were additionally associated with an improvement in OS (categorized by LLN of 2.05 g/l-10.4 vs. 5.5 months, HR 0.46, p?=?0.023; [ln] haptoglobin-HR 0.51, p?=?0.036). Pts with baseline SAA values below the MV of 22 mg/l also had a prolonged OS (10.4 vs. 5.0 months, HR 0.47, p?=?0.036). For 25-OH vitamin D3 levels, no significant correlation with OS was found. In multivariate analyses, pre-treatment CYFRA 21-1 levels (categorized by MV-HR 0.15, p?=?0.032) as well as [ln] haptoglobin (HR 0.30, p?=?0.006) retained their independent prognostic significance for OS. CYFRA 21-1, haptoglobin, and SAA might provide useful prognostic information in advanced PC. An external multicenter validation of these results is necessary. PMID:25472579

Haas, Michael; Kern, Christoph; Kruger, Stephan; Michl, Marlies; Modest, Dominik P; Giessen, Clemens; Schulz, Christoph; von Einem, Jobst C; Ormanns, Steffen; Laubender, Rüdiger P; Holdenrieder, Stefan; Heinemann, Volker; Boeck, Stefan

2014-12-01

299

Protein interactions among Fe65, the low-density lipoprotein receptor-related protein, and the amyloid precursor protein.  

Science.gov (United States)

The adapter protein Fe65 has been proposed to be the link between the intracellular domains of the amyloid precursor protein, APP (AICD), and the low-density lipoprotein receptor-related protein (LRP-CT). Functional linkage between these two proteins has been established, and mutations within LRP-CT affect the amount of A? produced from APP. Previous work showed that AICD binds to protein interaction domain 2 (PID2) of Fe65. Although the structure of PID1 was determined recently, all attempts to demonstrate LRP-CT binding to this domain failed. We used biophysical experiments and binding studies to investigate the binding among these three proteins. Full-length Fe65 bound more weakly to AICD than did N-terminally truncated forms; however, the intramolecular domain-domain interactions that had been proposed to inhibit binding could not be observed using amide H-D exchange. Surprisingly, when LRP-CT is phosphorylated at Tyr4507, it bound to Fe65 PID1 despite the fact that this domain belongs to the Dab-like subclass of PIDs that are not supposed to be phosphorylation-dependent. Mutation of a critical arginine abolished binding, providing further proof of the phosphorylation dependence. Fe65 PID1 thus provides a link between the Dab-like class and the IRS-like class of PIDs and is the first Dab-like family member to show phosphorylation-dependent binding. PMID:21650223

Mulvihill, Melinda M; Guttman, Miklos; Komives, Elizabeth A

2011-07-19

300

Tetraspanin12 regulates ADAM10-dependent cleavage of amyloid precursor protein  

OpenAIRE

Using mass spectrometry, we identified ADAM10 (a membrane-associated metalloproteinase) as a partner for TSPAN12, a tetraspanin protein. TSPAN12-ADAM10 interaction was confirmed by reciprocal coimmunoprecipitation in multiple tumor cell lines. TSPAN12, to a greater extent than other tetraspanins (CD81, CD151, CD9, and CD82), associated with ADAM10 but not with ADAM17. Overexpression of TSPAN12 enhanced ADAM10-dependent shedding of amyloid precursor protein (APP) in MCF7 (breast cancer) and SH...

Xu, Daosong; Sharma, Chandan; Hemler, Martin E.

2009-01-01

301

Protein-induced Photophysical Changes to the Amyloid Indicator Dye Thioflavin T  

Energy Technology Data Exchange (ETDEWEB)

The small molecule thioflavin T (ThT) is a defining probe for the identification and mechanistic study of amyloid fiber formation. As such, ThT is fundamental to investigations of serious diseases such as Alzheimer's disease, Parkinson disease, and type II diabetes. For each disease, a different protein undergoes conformational conversion to a {beta}-sheet rich fiber. The fluorescence of ThT exhibits an increase in quantum yield upon binding these fibers. Despite its widespread use, the structural basis for binding specificity and for the changes to the photophysical properties of ThT remain poorly understood. Here, we report the co-crystal structures of ThT with two alternative states of {beta}-2 microglobulin ({beta}2m); one monomeric, the other an amyloid-like oligomer. In the latter, the dye intercalates between {beta}-sheets orthogonal to the {beta}-strands. Importantly, the fluorophore is bound in such a manner that a photophysically relevant torsion is limited to a range of angles generally associated with low, not high, quantum yield. Quantum mechanical assessment of the fluorophore shows the electronic distribution to be strongly stabilized by aromatic interactions with the protein. Monomeric {beta}2m gives little increase in ThT fluorescence despite showing three fluorophores, at two binding sites, in configurations generally associated with high quantum yield. Our efforts fundamentally extend existing understanding about the origins of amyloid-induced photophysical changes. Specifically, the {beta}-sheet interface that characterizes amyloid acts both sterically and electronically to stabilize the fluorophore's ground state electronic distribution. By preventing the fluorophore from adopting its preferred excited state configuration, nonradiative relaxation pathways are minimized and quantum yield is increased.

L Wolfe; M Calabrese; A Nath; D Blaho; A Miranker; Y Xiong

2011-12-31

302

Protein-induced photophysical changes to the amyloid indicator dye thioflavin T  

Energy Technology Data Exchange (ETDEWEB)

The small molecule thioflavin T (ThT) is a defining probe for the identification and mechanistic study of amyloid fiber formation. As such, ThT is fundamental to investigations of serious diseases such as Alzheimer's disease, Parkinson disease, and type II diabetes. For each disease, a different protein undergoes conformational conversion to a {beta}-sheet rich fiber. The fluorescence of ThT exhibits an increase in quantum yield upon binding these fibers. Despite its widespread use, the structural basis for binding specificity and for the changes to the photophysical properties of ThT remain poorly understood. Here, we report the co-crystal structures of ThT with two alternative states of {beta}-2 microglobulin ({beta}2m); one monomeric, the other an amyloid-like oligomer. In the latter, the dye intercalates between {beta}-sheets orthogonal to the {beta}-strands. Importantly, the fluorophore is bound in such a manner that a photophysically relevant torsion is limited to a range of angles generally associated with low, not high, quantum yield. Quantum mechanical assessment of the fluorophore shows the electronic distribution to be strongly stabilized by aromatic interactions with the protein. Monomeric {beta}2m gives little increase in ThT fluorescence despite showing three fluorophores, at two binding sites, in configurations generally associated with high quantum yield. Our efforts fundamentally extend existing understanding about the origins of amyloid-induced photophysical changes. Specifically, the {beta}-sheet interface that characterizes amyloid acts both sterically and electronically to stabilize the fluorophore's ground state electronic distribution. By preventing the fluorophore from adopting its preferred excited state configuration, nonradiative relaxation pathways are minimized and quantum yield is increased.

Wolfe, Leslie S.; Calabrese, Matthew F.; Nath, Abhinav; Blaho, Dorottya V.; Miranker, Andrew D.; Xiong, Yong (Yale)

2010-10-04

303

Distribution of precursor amyloid-?-protein messenger RNA in human cerebral cortex: relationship to neurofibrillary tangles and neuritic plaques  

International Nuclear Information System (INIS)

Neurofibrillary tangles (NFT) and neuritic plaques (NP), two neuropathological markers of Alzheimer disease, may both contain peptide fragments derived from the human amyloid ? protein. However, the nature of the relationship between NFT and NP and the source of the amyloid ? proteins found in each have remained unclear. The authors used in situ hybridization techniques to map the anatomical distribution of precursor amyloid-?-protein mRNA in the neocortex of brains from three subjects with no known neurologic disease and from five patients with Alzheimer disease. In brains from control subjects, positively hybridizing neurons were present in cortical regions and layers that contain a high density of neuropathological markers in Alzheimer disease, as well as in those loci that contain NP but few NFT. Quantitative analyses of in situ hybridization patterns within layers III and V of the superior frontal cortex revealed that the presence of high numbers of NFT in Alzheimer-diseased brains was associated with a decrease in the number of positively hybridizing neurons compared to controls and Alzheimer-diseased brains with few NFT. These findings suggest that the expression of precursor amyloid-?-protein mRNA may be a necessary but is clearly not a sufficient prerequisite for NFT formation. In addition, these results may indicate that the amyloid ? protein, present in NP in a given region or layer of cortex, is not derived from the resident neuronal cell bodies that e resident neuronal cell bodies that express the mRNA for the precursor protein

304

Distribution of precursor amyloid-. beta. -protein messenger RNA in human cerebral cortex: relationship to neurofibrillary tangles and neuritic plaques  

Energy Technology Data Exchange (ETDEWEB)

Neurofibrillary tangles (NFT) and neuritic plaques (NP), two neuropathological markers of Alzheimer disease, may both contain peptide fragments derived from the human amyloid ..beta.. protein. However, the nature of the relationship between NFT and NP and the source of the amyloid ..beta.. proteins found in each have remained unclear. The authors used in situ hybridization techniques to map the anatomical distribution of precursor amyloid-..beta..-protein mRNA in the neocortex of brains from three subjects with no known neurologic disease and from five patients with Alzheimer disease. In brains from control subjects, positively hybridizing neurons were present in cortical regions and layers that contain a high density of neuropathological markers in Alzheimer disease, as well as in those loci that contain NP but few NFT. Quantitative analyses of in situ hybridization patterns within layers III and V of the superior frontal cortex revealed that the presence of high numbers of NFT in Alzheimer-diseased brains was associated with a decrease in the number of positively hybridizing neurons compared to controls and Alzheimer-diseased brains with few NFT. These findings suggest that the expression of precursor amyloid-..beta..-protein mRNA may be a necessary but is clearly not a sufficient prerequisite for NFT formation. In addition, these results may indicate that the amyloid ..beta.. protein, present in NP in a given region or layer of cortex, is not derived from the resident neuronal cell bodies that express the mRNA for the precursor protein.

Lewis, D.A.; Higgins, G.A.; Young, W.G.; Goldgaber, D.; Gajdusek, D.C.; Wilson, M.C.; Morrison, J.H.

1988-03-01

305

Assessment of serum protein dynamics by native SILAC flooding (SILflood).  

Science.gov (United States)

Turnover of blood serum proteins is a vital function in mammals, but technical challenges have thus far prevented comprehensive measurements of serum protein half-lives. Here, we injected native serum from heavy stable isotope labeled (SIL) mice into nonlabeled recipients to quantify turnover of more than 200 proteins using mass spectrometry with high reproducibility and accuracy. We found a median of 19.4 h and a total range of 6-70 h for calculated half-lives. Moreover, we observed similar half-lives for proteins with equal function. To demonstrate the value and effectiveness of SILflood, we investigated the impaired serum clearance in ?2-microglobulin (B2M-/-) deficient mice. Notably, we found that serum albumin and IgG half-lives were clearly reduced in B2M deficient animals compared to control animals. Taken together, our results demonstrate that SILflood is a versatile tool to investigate serum half-lives under regular and pathological conditions in living animals. PMID:25347402

Nolte, Hendrik; Hölper, Soraya; Selbach, Matthias; Braun, Thomas; Krüger, Marcus

2014-11-18

306

The binding of americium and curium to human serum proteins  

International Nuclear Information System (INIS)

Human serum labelled with americium or curium has been separated by affinity chromatography. The results indicate that the only protein binding these actinides is transferrin, not albumin. Similar experiments with rat serum gave poor resolution of transferrin and albumin, due to the lower affinity of rat albumin for the Blue Sepharose. The reason for the low recoveries of radioactivity during the chromatographic process was investigated. Dissociation of the protein-actinide complex followed by competition between the gell matrix and the protein for the actinide was suspected to be responsible. Results showed that for both labelled human and rat serum, the proportion of americium eluting in the protein fractions decreased with the flow rate, confirming the suspicions of dissociation. (U.K.)

307

Application of ProteinChip array profiling in serum biomarker discovery for patients suffering from severe acute respiratory syndrome.  

Science.gov (United States)

A new strain of coronavirus has caused an outbreak of severe acute respiratory syndrome (SARS) from 2002 to 2003 resulting in 774 deaths worldwide. By protein chip array profiling technology, a number of serum biomarkers that might be useful in monitoring the clinical course of SARS patients were identified. This book chapter describes how the protein chip array profiling was carried out for this study. Briefly, SARS patients' serum samples were first fractionated in Q Ceramic HyperD ion exchange sorbent beads by buffers at different pH. Serum protein fractions thus obtained were then bound onto a copper (II) immobilized metal affinity capture (IMAC30 Cu [II]) ProteinChip Array or a weak cation-exchange (CM10) ProteinChip Array. After washing and addition of sinapinic acid, the chips were read in a Protein Biological System (PBS) IIc mass spectrometer. Ions were generated by laser shots and flied in a time of flight mode to the ion detector according to their mass over charge (m/z) ratio. The serum profiling spectra in SARS patients were acquired, baseline subtracted and analyzed in parallel with those from the control subjects by Ciphergen ProteinChip Software 3.0.2 with their peak intensities compared by a nonparametric two sample Mann-Whitney-U test. More than twelve peaks were differentially expressed in SARS patients with one at m/z of 11,695 (later identified to be serum amyloid A protein), which had increase in peak intensity correlating with the extent of SARS-coronavirus induced pneumonia as defined by a serial chest X-ray opacity score. The remaining biomarkers could also be useful in the study of other clinical parameters in SARS patients. PMID:18220240

Yip, Timothy T C; Cho, William C S; Cheng, Wai Wai; Chan, Johnny W M; Ma, Victor W S; Yip, Tai-Tung; Lau Yip, Christine N B; Ngan, Roger K C; Law, Stephen C K

2007-01-01

308

Bacterial curli protein promotes the conversion of PAP248-286 into the amyloid SEVI: cross-seeding of dissimilar amyloid sequences  

Directory of Open Access Journals (Sweden)

Full Text Available Fragments of prostatic acid phosphatase (PAP248-286 in human semen dramatically increase HIV infection efficiency by increasing virus adhesion to target cells. PAP248-286 only enhances HIV infection in the form of amyloid aggregates termed SEVI (Semen Enhancer of Viral Infection, however monomeric PAP248-286 aggregates very slowly in isolation. It has therefore been suggested that SEVI fiber formation in vivo may be promoted by exogenous factors. We show here that a bacterially-produced extracellular amyloid (curli or Csg acts as a catalytic agent for SEVI formation from PAP248-286 at low concentrations in vitro, producing fibers that retain the ability to enhance HIV (Human Immunodeficiency Virus infection. Kinetic analysis of the cross-seeding effect shows an unusual pattern. Cross-seeding PAP248-286 with curli only moderately affects the nucleation rate while significantly enhancing the growth of fibers from existing nuclei. This pattern is in contrast to most previous observations of cross-seeding, which show cross-seeding partially bypasses the nucleation step but has little effect on fiber elongation. Seeding other amyloidogenic proteins (IAPP (islet amyloid polypeptide and A?1?40 with curli showed varied results. Curli cross-seeding decreased the lag-time of IAPP amyloid formation but strongly inhibited IAPP elongation. Curli cross-seeding exerted a complicated concentration dependent effect on A?1?40 fibrillogenesis kinetics. Combined, these results suggest that the interaction of amyloidogenic proteins with preformed fibers of a different type can take a variety of forms and is not limited to epitaxial nucleation between proteins of similar sequence. The ability of curli fibers to interact with proteins of dissimilar sequences suggests cross-seeding may be a more general phenomenon than previously supposed.

Kevin Hartman

2013-02-01

309

Role of sequence and membrane composition in structure of transmembrane domain of Amyloid Precursor Protein  

Science.gov (United States)

Aggregation of proteins of known sequence is linked to a variety of neurodegenerative disorders. The amyloid ? (A?) protein associated with Alzheimer's Disease (AD) is derived from cleavage of the 99 amino acid C-terminal fragment of Amyloid Precursor Protein (APP-C99) by ?-secretase. Certain familial mutations of APP-C99 have been shown to lead to altered production of A? protein and the early onset of AD. We describe simulation studies exploring the structure of APP-C99 in micelle and membrane environments. Our studies explore how changes in sequence and membrane composition influence (1) the structure of monomeric APP-C99 and (2) APP-C99 homodimer structure and stability. Comparison of simulation results with recent NMR studies of APP-C99 monomers and dimers in micelle and bicelle environments provide insight into how critical aspects of APP-C99 structure and dimerization correlate with secretase processing, an essential component of the A? protein aggregation pathway and AD.

Straub, John

2013-03-01

310

Quantification of amyloid precursor protein isoforms using quantification concatamer internal standard.  

Science.gov (United States)

It is likely that expression and/or post-translational generation of various protein isoforms can be indicative of initial pathological changes or pathology development. However, selective quantification of individual protein isoforms remains a challenge, because they simultaneously possess common and unique amino acid sequences. Quantification concatamer (QconCAT) internal standards were originally designed for a large-scale proteome quantification and are artificial proteins that are concatamers of tryptic peptides for several proteins. We developed a QconCAT for quantification of various isoforms of amyloid precursor protein (APP). APP-QconCAT includes tryptic peptides that are common for all isoforms of APP concatenated with those tryptic peptides that are unique for specific APP isoforms. Isotope-labeled APP-QconCAT was expressed, purified, characterized, and further used for quantification of total APP, APP695, and amyloid-? (A?) in the human frontal cortex from control and severe Alzheimer's disease donors. Potential biological implications of our quantitative measurements are discussed. It is also expected that using APP-QconCAT(s) will advance our understanding of biological mechanism by which various APP isoforms involved in the pathogenesis of Alzheimer's disease. PMID:23186391

Chen, Junjun; Wang, Meiyao; Turko, Illarion V

2013-01-01

311

Cellular Prion Protein Mediates Toxic Signaling of Amyloid Beta  

OpenAIRE

Prion diseases in humans and animals comprise a group of invariably fatal neurodegenerative diseases characterized by the formation of a pathogenic protein conformer designated PrPSc and infectious particles denoted prions. The cellular prion protein (PrPC) has a central role in the pathogenesis of prion disease. First, it is the precursor of PrPSc and infectious prions and second, its expression on neuronal cells is required to mediate toxic effects of prions. To specifically study the role ...

Resenberger, Ulrike K.; Winklhofer, Konstanze F.; Tatzelt, Jo?rg

2012-01-01

312

Systematic study of plasma and serum proteins in the pig  

International Nuclear Information System (INIS)

This work has been carried out in the framework of the determination of the physiological constants of a normal pig. The aim was to study the serum and plasma proteins of this animal species, the ultimate object being to discover whether the qualitative and quantitative changes in these proteins can make a significant contribution to the establishment of a biological dosimetry for irradiated pigs. The serum and plasma from a normal pig were analyzed first by various simple electrophoretic methods and then by immuno-electrophoresis. As a result of the particular characteristics of pig serum we have gradually been led to make numerous modifications to the techniques used for human serums or for those of small laboratory animals. Much careful work and patience were required in order to obtain reproducible results. (authors)

313

Vaccinium uliginosum L. Improves Amyloid ? Protein-Induced Learning and Memory Impairment in Alzheimer's Disease in Mice.  

Science.gov (United States)

The present study investigated the effects of Vaccinium uliginosum L. (bilberry) on the learning and memory impairments induced by amyloid-? protein (A?P) 1-42. ICR Swiss mice were divided into 4 groups: the control (A?40-1A), control with 5% bilberry group (A?40-1B), amyloid ? protein 1-42 treated group (A?1-42A), and A?1-42 with 5% bilberry group (A?1-42B). The control was treated with amyloid ?-protein 40-1 for placebo effect, and Alzheimer's disease (AD) group was treated with amyloid ?-protein 1-42. Amyloid ?-protein 1-42 was intracerebroventricular (ICV) micro injected into the hippocampus in 35% acetonitrile and 0.1% trifluoroacetic acid. Although bilberry added groups tended to decrease the finding time of hidden platform, no statistical significance was found. On the other hand, escape latencies of A?P injected mice were extended compared to that of A?40-1. In the Probe test, bilberry added A?1-42B group showed a significant (Pgroup. In passive avoidance test, bilberry significantly (Plearning capability in chemically induced Alzheimer's disease in experimental animal models. PMID:25580400

Choi, Yoon-Hee; Kwon, Hyuck-Se; Shin, Se-Gye; Chung, Cha-Kwon

2014-12-01

314

Inhibition of amyloid precursor protein secretases reduces recovery after spinal cord injury.  

Science.gov (United States)

Amyloid-? (A?) is produced through the enzymatic cleavage of amyloid precursor protein (APP) by ? (Bace1) and ?-secretases. The accumulation and aggregation of A? as amyloid plaques is the hallmark pathology of Alzheimer?s disease and has been found in other neurological disorders, such as traumatic brain injury and multiple sclerosis. Although the role of A? after injury is not well understood, several studies have reported a negative correlation between A? formation and functional outcome. In this study we show that levels of APP, the enzymes cleaving APP (Bace1 and ?-secretase), and A? are significantly increased from 1 to 3 days after impact spinal cord injury (SCI) in mice. To determine the role of A? after SCI, we reduced or inhibited A? in vivo through pharmacological (using DAPT) or genetic (Bace1 knockout mice) approaches. We found that these interventions significantly impaired functional recovery as evaluated by white matter sparing and behavioral testing. These data are consistent with a beneficial role for A? after SCI. PMID:24630972

Pajoohesh-Ganji, Ahdeah; Burns, Mark P; Pal-Ghosh, Sonali; Tadvalkar, Gauri; Hokenbury, Nicole G; Stepp, Mary Ann; Faden, Alan I

2014-04-29

315

Cysteine 27 Variant of the ?-Opioid Receptor Affects Amyloid Precursor Protein Processing through Altered Endocytic Trafficking ?  

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Agonist-induced activation of the ?-opioid receptor (?OR) was recently shown to augment ?- and ?-secretase activities, which increased the production of ?-amyloid peptide (A?), known to accumulate in the brain tissues of Alzheimer's disease (AD) patients. Previously, the ?OR variant with a phenylalanine at position 27 (?OR-Phe27) exhibited more efficient receptor maturation and higher stability at the cell surface than did the less common cysteine (?OR-Cys27) variant. For this study, we expressed these variants in human SH-SY5Y and HEK293 cells expressing exogenous or endogenous amyloid precursor protein (APP) and assessed the effects on APP processing. Expression of ?OR-Cys27, but not ?OR-Phe27, resulted in a robust accumulation of the APP C83 C-terminal fragment and the APP intracellular domain, while the total soluble APP and, particularly, the ?-amyloid 40 levels were decreased. These changes upon ?OR-Cys27 expression coincided with decreased localization of APP C-terminal fragments in late endosomes and lysosomes. Importantly, a long-term treatment with a subset of ?OR-specific ligands or a c-Src tyrosine kinase inhibitor suppressed the ?OR-Cys27-induced APP phenotype. These data suggest that an increased constitutive internalization and/or concurrent signaling of the ?OR-Cys27 variant affects APP processing through altered endocytic trafficking of APP. PMID:21464208

Sarajärvi, Timo; Tuusa, Jussi T.; Haapasalo, Annakaisa; Lackman, Jarkko J.; Sormunen, Raija; Helisalmi, Seppo; Roehr, Johannes T.; Parrado, Antonio R.; Mäkinen, Petra; Bertram, Lars; Soininen, Hilkka; Tanzi, Rudolph E.; Petäjä-Repo, Ulla E.; Hiltunen, Mikko

2011-01-01

316

Amyloid ?-Protein as a Substrate Interacts with Extracellular Matrix to Promote Neurite Outgrowth  

Science.gov (United States)

Progressive deposition of amyloid ?-protein (A?) in brain parenchyma and blood vessels is a characteristic feature of Alzheimer disease. Recent evidence suggests that addition of solubilized synthetic A? to medium may produce toxic or trophic effects on cultured hippocampal neurons. Because soluble A? may not accumulate in significant quantities in brain, we asked whether immobilized A? peptide as a substrate alters neurite outgrowth from cultured rat peripheral sensory neurons. This paradigm may closely mimic the conditions in Alzheimer disease brain tissue, in which neurites contact insoluble, extracellular aggregates of ?-amyloid. We detected no detrimental effects of A? substrate on neurite outgrowth. Rather, A? in combination with low doses of laminin or fibronectin enhanced neurite out-growth from these neuronal explants. Our results suggest that insoluble A? in the cerebral neuropil may serve as a neurite-promoting matrix, perhaps explaining the apparent regenerative response of neurites observed around amyloid plaques in Alzheimer disease. Moreover, in concert with the recent discovery of A? production by cultured neurons, our data suggest that A? plays a normal physiological role in brain by complexing with the extracellular matrix.

Koo, Edward H.; Park, Lisa; Selkoe, Dennis J.

1993-05-01

317

Functional analysis of the accessory protein TapA in Bacillus subtilis amyloid fiber assembly.  

Science.gov (United States)

Bacillus subtilis biofilm formation relies on the assembly of a fibrous scaffold formed by the protein TasA. TasA polymerizes into highly stable fibers with biochemical and morphological features of functional amyloids. Previously, we showed that assembly of TasA fibers requires the auxiliary protein TapA. In this study, we investigated the roles of TapA sequences from the C-terminal and N-terminal ends and TapA cysteine residues in its ability to promote the assembly of TasA amyloid-like fibers. We found that the cysteine residues are not essential for the formation of TasA fibers, as their replacement by alanine residues resulted in only minor defects in biofilm formation. Mutating sequences in the C-terminal half had no effect on biofilm formation. However, we identified a sequence of 8 amino acids in the N terminus that is key for TasA fiber formation. Strains expressing TapA lacking these 8 residues were completely defective in biofilm formation. In addition, this TapA mutant protein exhibited a dominant negative effect on TasA fiber formation. Even in the presence of wild-type TapA, the mutant protein inhibited fiber assembly in vitro and delayed biofilm formation in vivo. We propose that this 8-residue sequence is crucial for the formation of amyloid-like fibers on the cell surface, perhaps by mediating the interaction between TapA or TapA and TasA molecules. PMID:24488317

Romero, Diego; Vlamakis, Hera; Losick, Richard; Kolter, Roberto

2014-04-01

318

Serum C-reactive protein in dairy herds  

OpenAIRE

The purpose of this study was to determine the relationship between the serum level of C-reactive protein (CRP) and lactation and health status. Blood samples were collected every 2 wk for 12 mo from 29 randomly selected dairy cattle on 3 farms. At the time the blood samples were collected, the stage of pregnancy, lactation status, breeding records, general health condition, reproductive status, and body condition score were recorded for each cow. Serum CRP was detected with sodium dodecyl su...

Lee, Wen-chuan; Hsiao, Huo-cheng; Wu, Ying-ling; Lin, Jyh-hung; Lee, Yen-pai; Fung, Hang-poung; Chen, Hsin-hsin; Chen, Yu-hsin; Chu, Rea-min

2003-01-01

319

Serum Copper and Plasma Protein Status in Normal Pregnancy  

Directory of Open Access Journals (Sweden)

Full Text Available AbstractBackground: Gradual alteration of serum copper and some plasma protein levels may occur with advancement of pregnancy, which is associated with increased maternal and infant morbidity and mortality.Objective: To observe serum copper and plasma protein levels in normal pregnant women of different trimesters in order to find out their nutritional status.Methods: This cross sectional study was carried out in the Department of Physiology, Sir Salimullah Medical College (SSMC, Dhaka, between 1st January 2010 and December 2010. Ninety normal pregnant women of different trimesters with age 20-30 years were included in the study group. They were selected from Out Patient Department of Obstetrics and Gynaecology, SSMC. Age matched 30 non-pregnant women were taken as control. Serum copper level was measured by Spectrophotometric method, serum total protein and albumin levels were estimated by standard method. Statistical analysis was done by one way ANOVA, Bonferroni and Pearson’s correlation coefficient test as applicable.Results: Serum Cu levels were significantly higher in all trimesters of pregnant women compared to control. Again, this value was significantly higher in 3rd trimester than that of in 1st and 2nd trimester and also in 2nd trimester than that of in 1st trimester. In addition, mean serum total protein level was significantly lower in 3rd trimester than control but no statistically significant difference was observed among different trimesters. Again, mean serum albumin level was significantly lower in 2nd and 3rd trimester than 1st trimester and control. In addition, serum Cu concentration showed significant positive correlation with different trimesters of gestation.Conclusion: This study reveals that hypercupremia along with hypoproteinemia occur in pregnant women from 1st to 3rd trimester of gestation. This gradual alteration of micro and macronutrients become more profound with advancement of pregnancy.

Nushrat Noor, Nasim Jahan, Nayma Sultana

2012-12-01

320

Screening serum hepatocellular carcinoma-associated proteins by SELDI-based protein spectrum analysis  

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Full Text Available AIM: To find out potential serum hepatocellular carcinoma (HCC-associated proteins with low molecular weight and low abundance by SELDI-based serum protein spectra analysis, that will have much application in the diagnosis or differentiated diagnosis of HCC, as well as giving a better understanding of the mechanism of hepato-carcinogenesis.METHODS: Total serum samples were collected with informed consent from 81 HCC patients with HBV(+/cirrhosis(+, 36 cirrhosis patients and 43 chronic hepatitis B patients. Serum protein fingerprint profiles were first generated by selected WCX2 protein chip capture integrating with SELDI-TOF-MS, then normalized and aligned by Ciphergen SELDI Software 3.1.1 with Biomarker Wizard. Comparative analysis of the intensity of corresponding protein fingerprint peaks in normalized protein spectra, some protein peaks with significant difference between HCC and cirrhosis or chronic hepatitis B were found.RESULTS: One hundred and twenty-eight serum protein peaks between 2000 and 30 000Da were identified under the condition of signal-to-noise > 5 and minimum threshold for cluster > 20%. Eighty-seven of these proteins were showed significant differences in intensity between HCC and cirrhosis (P < 0.05. Of the above differential proteins, 45 proteins had changes greater than two-fold, including 15 upregulated proteins and 30 downregulated proteins in HCC serum. Between HCC and chronic hepatitis B, 9 of 52 differential proteins (P < 0.05 had intensities of more than two-fold, including 2 upregulated proteins and 7 downregulated proteins in HCC serum. Between cirrhosis and chronic hepatitis B, 28 of 79 significant differential proteins (P < 0.05 changes greater than two-fold in intensity, including 17 upregulated proteins and 11 downregulated proteins in cirrhosis serum. For the analysis of these leading differential proteins in subtraction difference mode among three diseases, the five common downregulated proteins in HCC serum (M/Z 2870, 3941, 2688, 3165, 5483 and two common upregulated proteins (M/Z 3588, 2017 in HCC and cirrhosis serum were screened.CONCLUSION: Because the interference of unspecific secreted proteins from hepatitis B and cirrhosis could be eliminated partly in HCC serum under subtraction difference analysis, these seven common differential proteins have the obvious advantage of specificity for evaluating the pathological state of HCC and might become novel candidate biomarkers in the diagnosis of HCC.

Jie-Feng Cui, Yin-Kun Liu, Hai-Jun Zhou, Xiao-Nan Kang, Cheng Huang, Yi-Feng He, Zhao-You Tang, Toshimasa Uemura

2008-02-01

321

Effect of stent-assisted angioplasty on cognitive status and serum levels of amyloid beta in patients with intracranial and/or extracranial artery stenosis  

Science.gov (United States)

Aim The study reported here aimed to examine how stent-assisted angioplasty affects cognitive status and serum levels of amyloid betas (A?s) 1-40 and 1-42 in patients with cerebral arterial stenosis. Methods Patients with cerebral arterial stenosis were given stent-assisted angioplasty plus conventional treatment (stent-assisted angioplasty group) or conventional treatment alone (control group). Cognitive status and A?1-40 and A?1-42 serum levels were determined before treatment and at 4 and 8 weeks after treatment. Results At 4 weeks after treatment, cognitive status in patients with stent-assisted angioplasty had clearly improved. A?1-42 serum levels changed insignificantly in all patients. However, A?1-40 serum levels and A?1-40/A?1-42 ratio decreased further in patients with stent-assisted angioplasty than in patients who received conventional treatment (controls). Eight weeks after treatment, cognitive status in patients who had undergone stent-assisted angioplasty were continuing to improve, A?1-42 serum levels had begun to increase dramatically, and A?1-40 serum levels and A?1-40/A?1-42 ratio had declined further. Conclusion Stent-assisted angioplasty could improve cognitive status and decrease A?1-40 serum levels and A?1-40/A?1-42 ratio. PMID:25750527

Zhao, Liandong; Zhao, Ying; Zhang, Haijun

2015-01-01

322

The binding constant for amyloid Abeta40 peptide interaction with human serum albumin.  

Science.gov (United States)

Human serum albumin (HSA) is the major carrier of Abeta peptides in blood plasma. 1:1 interaction stoichiometries were established in previous indirect antibody-based studies for both Abeta40 and Abeta42, but corresponding binding constants were not provided. In this study we applied direct titrations of HSA with Abeta40 monitored using circular dichroism spectroscopy and obtained a dissociation constant (K(d)) of 5+/-1 microM for a HSA complex with Abeta40. The interaction resulted in an increase of the alpha-helical contents in the complex, compared to its components, which is quantitatively consistent with the known ability of Abeta40 to adopt a partially alpha-helical conformation in a hydrophobic environment. The relevance of these findings for the role of HSA in Abeta physiology is discussed. PMID:18028874

Rózga, Ma?gorzata; K?oniecki, Marcin; Jab?onowska, Agnieszka; Dadlez, Micha?; Bal, Wojciech

2007-12-21

323

The Alzheimer Amyloid Precursor Protein (APP) and Fe65, an APP-Binding Protein, Regulate Cell Movement  

OpenAIRE

FE65 binds to the Alzheimer amyloid precursor protein (APP), but the function of this interaction has not been identified. Here, we report that APP and FE65 are involved in regulation of cell movement. APP and FE65 colocalize with actin and Mena, an Abl-associated signaling protein thought to regulate actin dynamics, in lamellipodia. APP and FE65 specifically concentrate with ?1-integrin in dynamic adhesion sites known as focal complexes, but not in more static adhesion sites known as focal ...

Sabo, Shasta L.; Ikin, Annat F.; Buxbaum, Joseph D.; Greengard, Paul

2001-01-01

324

Genetic and environmental influences of surfactant protein D serum levels  

DEFF Research Database (Denmark)

The collectin surfactant protein D (SP-D) is an important component of the pulmonary innate immune system, but SP-D is also present on extrapulmonary epithelial surfaces and in serum, where it has been used as a biomarker for pulmonary disease states. In this study, we investigate the mechanisms defining the constitutional serum level of SP-D and determine the magnitude of the genetic contribution to serum SP-D in the adult population. Recent studies have demonstrated that serum SP-D concentrations in children are genetically determined and that a single nucleotide polymorphism (SNP) located in the NH(2)-terminal region (Met11Thr) of the mature protein is significantly associated with the serum SP-D levels. A classic twin study was performed on a twin population including 1,476 self-reported healthy adults. The serum SP-D levels increased with male sex, age, and smoking status. The intraclass correlation was significantly higher for monozygotic (MZ) twin pairs than for dizygotic (DZ) twin pairs. Serum SP-D variance was influenced by nonshared environmental effects and additive genetic effects. Multivariate analysis of MZ and DZ covariance matrixes showed significant genetic correlation among serum SP-D and metabolic variables. The Met11Thr variant explained a significant part of the heritability indicating that serum SP-D variance could be decomposed into non-shared environmental effects (e(2) = 0.19), additive genetic effects (h(2) = 0.42), and the effect of the Met11Thr variations (q(2) = 0.39).

Sorensen, G.L.; Hjelmborg, J.V.

2006-01-01

325

Manipulations of amyloid precursor protein cleavage disrupt the circadian clock in aging Drosophila.  

Science.gov (United States)

Alzheimer's disease (AD) is a neurodegenerative disease characterized by severe cognitive deterioration. While causes of AD pathology are debated, a large body of evidence suggests that increased cleavage of Amyloid Precursor Protein (APP) producing the neurotoxic Amyloid-? (A?) peptide plays a fundamental role in AD pathogenesis. One of the detrimental behavioral symptoms commonly associated with AD is the fragmentation of sleep-activity cycles with increased nighttime activity and daytime naps in humans. Sleep-activity cycles, as well as physiological and cellular rhythms, which may be important for neuronal homeostasis, are generated by a molecular system known as the circadian clock. Links between AD and the circadian system are increasingly evident but not well understood. Here we examined whether genetic manipulations of APP-like (APPL) protein cleavage in Drosophila melanogaster affect rest-activity rhythms and core circadian clock function in this model organism. We show that the increased ?-cleavage of endogenous APPL by the ?-secretase (dBACE) severely disrupts circadian behavior and leads to reduced expression of clock protein PER in central clock neurons of aging flies. Our data suggest that behavioral rhythm disruption is not a product of APPL-derived A? production but rather may be caused by a mechanism common to both ? and ?-cleavage pathways. Specifically, we show that increased production of the endogenous Drosophila Amyloid Intracellular Domain (dAICD) caused disruption of circadian rest-activity rhythms, while flies overexpressing endogenous APPL maintained stronger circadian rhythms during aging. In summary, our study offers a novel entry point toward understanding the mechanism of circadian rhythm disruption in Alzheimer's disease. PMID:25766673

Blake, Matthew R; Holbrook, Scott D; Kotwica-Rolinska, Joanna; Chow, Eileen S; Kretzschmar, Doris; Giebultowicz, Jadwiga M

2015-05-01

326

Overproduction, purification, crystallization and preliminary X-ray analysis of human Fe65-PTB2 in complex with the amyloid precursor protein intracellular domain  

OpenAIRE

Alzheimer’s disease is characterized by proteolytic processing of the amyloid precursor protein (APP), which releases the aggregation-prone amyloid-? (A?) peptide and liberates the intracellular domain (AICD) that interacts with various adaptor proteins. The crystallized AICD–Fe65-PTB2 complex is of central importance for APP translocation, nuclear signalling, processing and A? generation.

Radzimanowski, Jens; Beyreuther, Konrad; Sinning, Irmgard; Wild, Klemens

2008-01-01

327

First identification of resident and circulating fibrocytes in Dupuytren's disease shown to be inhibited by serum amyloid P and Xiapex.  

Science.gov (United States)

Dupuytren's disease (DD) is a common progressive fibroproliferative disorder causing permanent digital contracture. Proliferative myofibroblasts are thought to be the cells responsible for DD initiation and recurrence, although their source remains unknown. DD tissue has also been shown to harbor mesenchymal and hematopoietic stem cells. Fibrocytes are circulating cells that show characteristics of fibroblasts and they express surface markers for both hematopoietic and mesenchymal stromal cells. Fibrocytes differentiate from peripheral CD14+ mononuclear cells, which can be inhibited by serum amyloid P (SAP). In this study we have demonstrated the presence of fibrocytes in DD blood and tissue, moreover we have evaluated the effects of SAP and Xiapex (Collagenase Clostridium histolyticum) on fibrocytes derived from DD. H&E staining showed typical Spindle shaped morphology of fibrocytes. FACS analysis based on a unique combination of 3 markers, revealed the increased presence of fibrocytes in blood and tissue of DD patients. Additionally, immunohistology of DD nodule and cord tissue showed the presence of collagen 1+/CD34+ cells. No difference in plasma SAP levels was observed between DD and control. Higher concentrations of SAP significantly inhibited fibrocytes differentiated from DD derived monocytes compared to control. DD fascia derived fibrocytes showed resistance to growth inhibition by SAP, particularly nodule derived fibrocytes showed robust growth even at higher SAP concentrations compared to control. DD derived fibrocytes were positive for typical fibrocyte dual markers, i.e. Collagen 1/LSP-1 and collagen 1/CD34. Xiapex was more effective in inhibiting the growth of nodule derived cells compared to commercially available collagenase A. Our results show for the first time the increased presence of fibrocytes in DD patient's blood and disease tissue compared to control tissue. Additionally, we evaluate the response of these fibrocytes to SAP and Xiapex therapy. PMID:24933153

Iqbal, Syed Amir; Hayton, Michael John; Watson, James Stewart; Szczypa, Piotr; Bayat, Ardeshir

2014-01-01

328

Human antibodies reactive with beta-amyloid protein in Alzheimer's disease  

OpenAIRE

Four human B cell lines established by Epstein-Barr viral transformation of B cells from a patient with a clinical diagnosis of Alzheimer's disease (AD) were found to secrete antibodies that react with plaques and cerebrovascular blood vessels in AD brain in a staining profile characteristic of beta-amyloid protein (beta-AP) in AD brain. Two of these antibodies were shown to be reactive with a rare plaque in a normal brain. In these studies, immunofluorescence and avidin-biotin complex immuno...

1993-01-01

329

Cellular prion protein participates in amyloid-? transcytosis across the blood–brain barrier  

OpenAIRE

The blood–brain barrier (BBB) facilitates amyloid-? (A?) exchange between the blood and the brain. Here, we found that the cellular prion protein (PrPc), a putative receptor implicated in mediating A? neurotoxicity in Alzheimer's disease (AD), participates in A? transcytosis across the BBB. Using an in vitro BBB model, [125I]-A?1?40 transcytosis was reduced by genetic knockout of PrPc or after addition of a competing PrPc-specific antibody. Furthermore, we provide evidence that PrPc ...

Pflanzner, Thorsten; Petsch, Benjamin; Andre?-dohmen, Bettina; Mu?ller-schiffmann, Andreas; Tschickardt, Sabrina; Weggen, Sascha; Stitz, Lothar; Korth, Carsten; Pietrzik, Claus U.

2012-01-01

330

Parkinson's Disease Iron Deposition Caused by Nitric Oxide-Induced Loss of ?-Amyloid Precursor Protein.  

Science.gov (United States)

Elevation of both neuronal iron and nitric oxide (NO) in the substantia nigra are associated with Parkinson's disease (PD) pathogenesis. We reported previously that the Alzheimer-associated ?-amyloid precursor protein (APP) facilitates neuronal iron export. Here we report markedly decreased APP expression in dopaminergic neurons of human PD nigra and that APP(-/-) mice develop iron-dependent nigral cell loss. Conversely, APP-overexpressing mice are protected in the MPTP PD model. NO suppresses APP translation in mouse MPTP models, explaining how elevated NO causes iron-dependent neurodegeneration in PD. PMID:25716857

Ayton, Scott; Lei, Peng; Hare, Dominic J; Duce, James A; George, Jessica L; Adlard, Paul A; McLean, Catriona; Rogers, Jack T; Cherny, Robert A; Finkelstein, David I; Bush, Ashley I

2015-02-25

331

hnRNP C increases amyloid precursor protein (APP) production by stabilizing APP mRNA.  

OpenAIRE

We have previously shown that heterogeneous nuclear ribonucleoprotein C (hnRNP C) and nucleolin bound specifically to a 29 nt sequence in the 3'-untranslated region of amyloid precursor protein (APP) mRNA. Upon activation of peripheral blood mononuclear cells, hnRNP C and nucleolin acquired APP mRNA binding activity, concurrent with APP mRNA stabilization. These data suggested that the regulated interaction of hnRNP C and nucleolin with APP mRNA controlled its stability. Here we have directly...

Rajagopalan, L. E.; Westmark, C. J.; Jarzembowski, J. A.; Malter, J. S.

1998-01-01

332

Amyloid Precursor Protein Regulates Brain Apolipoprotein E and Cholesterol Metabolism through Lipoprotein Receptor LRP1  

OpenAIRE

Mutations in the amyloid precursor protein (APP) cause early-onset Alzheimer's disease (AD), but the only genetic risk factor for late-onset AD is the ?4 allele of apolipoprotein E (apoE), a major cholesterol carrier. Using Cre-lox conditional knockout mice, we demonstrate that lipoprotein receptor LRP1 expression regulates apoE and cholesterol levels within the CNS. We also found that deletion of APP and its homologue APLP2, or components of the ?-secretase complex, significantly enhanced ...

Liu, Qiang; Zerbinatti, Celina V.; Zhang, Juan; Hoe, Hyang-sook; Wang, Baiping; Cole, Sarah L.; Herz, Joachim; Muglia, Louis; Bu, Guojun

2007-01-01

333

The histidine composition of the amyloid-? domain, but not the E1 copper binding domain, modulates ?-secretase processing of amyloid-? protein precursor in Alzheimer's disease.  

Science.gov (United States)

Amyloid-? protein precursor (A?PP) proteolysis by ?- and ?-secretases generates neurotoxic amyloid-? (A?)-peptides in Alzheimer's disease (AD). We have investigated the role of histidine residues within the extracellular E1 copper binding and A? domains of A?PP in its proteolysis. By stably expressing histidine to alanine A?PP mutant constructs in SH-SY5Y cells, we show that mutations in the E1 copper binding domain had no impact on ?- or ?-secretase processing. Mutation of histidine 14 within the A?-domain specifically down-regulated ?-secretase processing without impacting on non-amyloidogenic proteolysis. Understanding how histidine 14 participates in A?PP proteolysis may reveal new intervention points for AD treatments. PMID:25171714

Gough, Mallory; Blanthorn-Hazell, Sophee; Parkin, Edward T

2015-01-01

334

Use of serum protein concentration optimize penaeid spawner quality  

OpenAIRE

From June 1981 to September 1982, the serum protein concentration has been used as an index of shrimp's hea1th for P.monodon female selection in the maturation units at the COP (Vairao, Tahiti). Three lots were separated according to the food supply during the pregenitor's life and the spawning index (number of spawn per female and per month) was then monitored for each female. With a captive broodstock, a minimum serum protein concentration is needed for spawning ability. [NOT CONTROLLED OCR

AQUACOP

1983-01-01

335

Unraveling the mysteries of serum albumin—more than just a serum protein  

OpenAIRE

Serum albumin is a multi-functional protein that is able to bind and transport numerous endogenous and exogenous compounds. The development of albumin drug carriers is gaining increasing importance in the targeted delivery of cancer therapy, particularly as a result of the market approval of the paclitaxel-loaded albumin nanoparticle, Abraxane®. Considering this, there is renewed interest in isolating and characterizing albumin-binding proteins or receptors on the plasma membrane that are re...

Merlot, Angelica M.; Kalinowski, Danuta S.; Richardson, Des R.

2014-01-01

336

Unraveling the mysteries of serum albumin – more than just a serum protein.  

OpenAIRE

Serum albumin is a multi-functional protein that is able to bind and transport numerous endogenous and exogenous compounds. The development of albumin drug carriers is gaining increasing importance in the targeted delivery of cancer therapy, particularly as a result of the market approval of the paclitaxel-loaded albumin nanoparticle, Abraxane®. Considering this, there is renewed interest in isolating and characterizing albumin-binding proteins or receptors on the plasma membrane that are re...

AngelicaM.Merlot

2014-01-01

337

Serum amyloid A (SAA) as a biomarker of chronic infection due to boat strike trauma in a free-ranging Florida manatee (Trichechus manatus latirostris) with incidental polycystic kidneys.  

Science.gov (United States)

Watercraft-related trauma is the predominant cause of human-induced mortality in manatees (Trichechus manatus latirostris), a federal- and state-listed endangered species. Pyothorax (documented in this case report) and other secondary infections are common sequelae of inhalation of water and the open wounds caused by boat propellers. These secondary infections can lead to the demise of the animal weeks to months after the traumatic incident when external wounds have healed. Diagnosis of underlying disease on physical examination during capture and restraint can be difficult. Acute phase proteins, including serum amyloid A, fibrinogen, and albumin can be used to diagnose inflammatory disease in manatees and improve quality of medical care and husbandry. We also provide the first report of polycystic kidneys in Sirenians. PMID:22102678

Harr, Kendal E; Rember, Renee; Ginn, Pamela E; Lightsey, Jessica; Keller, Martha; Reid, James; Bonde, Robert K

2011-10-01

338

[The precursor of amyloid peptide in Alzheimer disease: a protein with multiple functions].  

Science.gov (United States)

Cellular metabolism of the amyloid precursor protein (APP) has been widely studied, but the function of the protein remains elusive. APP knock out mice do not show any phenotype, due to in vivo compensation by APLP genes, encoding proteins similar to APP. In order to study the neuronal metabolism of APP, human APP has been expressed in rat cortical neurons in culture. Following differentiation in culture, rat cortical neurons are organized into networks of connected cells, which show neuronal activity in the form of spontaneous and synchronous calcium oscillations. Expression of human APP in these neuronal networks inhibits calcium oscillations, while downregulation of endogenous APP expression increases the frequency and decreases the amplitude of oscillations. Therefore, APP controls neuronal calcium homeostasis and excitability. In the same experimental model, APP is also able to control the neuronal synthesis of cholesterol. Finally, the APP carboxy terminal domain is involved in the epigenetic control of gene expression. Modulation of neuronal expression of APP allows to identify several important functions of the precursor of the amyloid peptide found in senile plaques of Alzheimer disease. PMID:20218187

Octave, J N

2009-01-01

339

Serum protein inhibition of thyrotropin binding to human thyroid tissue  

International Nuclear Information System (INIS)

We used a modificaton of the TSH radioreceptor assay to detect TSH-binding inhibition (TBI) activity in serum and serum fractions from normal subjects and patients with Graves' disease. TBI activity is present in normal IgG prepared by DEAE-Sephadex chromatography and in normal globulins prepared by precipitation at 1.6 M ammonium sulfate. Other normal serum proteins also had TBI activity when large concentrations were tested. Gel filtration chromatography and powder block electrophoresis were used to prepare fractions of normal and Graves' disease sera. In these fractions from normal serum, TBI activity was found in both ?-globulin and ?-globulin-albumin fractions electrophoretically and in both 7S and 4S peaks from gel filtration. TBI activity from Graves' disease patients' sera was similarly distributed, but relatively more TBI accompanied the electrophoretic ?-globulins. Sepharose Protein-A and anti-IgG were used as immunoabsorbents to isolate and purify IgG from normal and Graves' disease sera. TBI activity in IgG was proportional to the IgG concentration, indicating that the TBI which migrates as a ?-globulin electrophoretically is an IgG and thus may possibly be an antibody. Inhibitory activity found in normal serum globulins and in the non-IgG fractions of both normal and abnormal sera seriously interferes with attempts to use the TSH radioreceptor assay to study the hypothesized anti-TSH receptor antibody in the serum of patients with Graves' disease of patients with Graves' disease

340

Expression of active secreted forms of human amyloid beta-protein precursor by recombinant baculovirus-infected insect cells.  

OpenAIRE

Three alternatively spliced forms of the amyloid precursor protein (APP), APP-695, APP-751, and APP-770, were expressed in the baculovirus expression vector system. The recombinant proteins were secreted into the culture medium by infected insect cells, and APP molecules were detected in insect cells and medium 2 days after infection with the recombinant APP-baculoviruses. A partial sequence of the NH2 terminus of the secreted protein revealed identity with the native secreted protein and sho...

Bhasin, R.; Nostrand, W. E.; Saitoh, T.; Donets, M. A.; Barnes, E. A.; Quitschke, W. W.; Goldgaber, D.

1991-01-01

341

On the subject of rigor in the study of amyloid ?-protein assembly.  

Science.gov (United States)

According to Thomas Kuhn, the success of 'normal science,' the science we all practice on a daily basis, depends on the adherence to, and practice of, a paradigm accepted by the scientific community. When great scientific upheavals occur, they involve the rejection of the current paradigm in favor of a new paradigm that better integrates the facts available and better predicts the behavior of a particular scientific system. In the field of Alzheimer's disease, a recent example of such a paradigm shift has been the apparent rejection of the 'amyloid cascade hypothesis,' promulgated by Hardy and Higgins in 1992 to explain the etiology of Alzheimer's disease, in favor of what has been referred to as the 'oligomer cascade hypothesis'. This paradigm shift has been breathtaking in its rapidity, its pervasiveness in the Alzheimer's disease field, and its adoption in an increasing number of other fields, including those of Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and the prionoses. However, these facts do not mean, a priori, that the experiments extant, and any re-interpretation of them, should be accepted by rote as support for the new paradigm. In the discussion that follows, I consider the foundational studies leading to the oligomer cascade hypothesis and evaluate the current state of the paradigm. I argue here that, more often than not, insufficient rigor has been applied in studies upon which this new paradigm has been based. Confusion, rather than clarity, has resulted. If the field is to make progress forward using as its paradigmatic basis amyloid ?-protein oligomerization, then an epistemological re-evaluation of the amyloid ?-protein oligomer system is required. PMID:23981712

Teplow, David B

2013-01-01

342

Identification of a 17-protein signature in the serum of lung cancer patients.  

Science.gov (United States)

Early detection of lung cancer may potentially help to improve the outcome of this fatal disease. Currently, no satisfactory laboratory tests are available to screen for this type of cancer. The aim of this study was to improve diagnostic procedures for lung cancer through the discovery of serum biomarkers using SELDI-TOF MS (surface-enhanced laser desorption/ionization time-of-flight mass spectrometry). Mass spectrometric profiling was applied to the serum of a total of 139 lung cancer patients and 158 healthy individuals for developing a prognostic signature. For validation, two separate groups were employed, comprising of 126 and 50 individuals, respectively. Informative regions of mass spectra were identified by forming protein mass clusters and identifying predictive clusters in a logistic regression model. A total of 17 differential predictive protein mass clusters were identified in patients with metastatic lung cancer disease compared to healthy individuals. These clusters provide for a robust risk prediction model. The sensitivity and specificity of this model was estimated to be 87.3 and 81.9%, respectively, for the first validation set, and 96.0 and 66.7%, respectively, for a second validation set of patients with early disease (stages I and II). A differential 11.5/11.7 kDa double-peak could be identified as serum amyloid alpha (SAA) by peptide mapping. Our data suggest that the SELDI-TOF MS technology in combination with a careful statistical analysis appears to be a useful experimental platform which delivers a rapid insight into the proteome of body fluids and may guide to identify novel biomarkers for lung cancer disease. PMID:20514471

Sreseli, Roman T; Binder, Harald; Kuhn, Madeleine; Digel, Werner; Veelken, Hendrik; Sienel, Wulf; Passlick, Bernward; Schumacher, Martin; Martens, Uwe M; Zimmermann, Stefan

2010-07-01

343

Amyloid-clearing proteins and their epigenetic regulation as a therapeutic target in Alzheimer’s disease  

Directory of Open Access Journals (Sweden)

Full Text Available Abnormal elevation of amyloid ?-peptide (A? levels in the brain is the primary trigger for neuronal cell death specific to Alzheimer’s disease (AD. It is now evident that A? levels in the brain are manipulable due to a dynamic equilibrium between its production from the amyloid precursor protein (APP and removal by amyloid clearance proteins. Clearance can be either enzymic or non-enzymic (binding/transport proteins. Intriguingly several of the main amyloid-degrading enzymes (ADEs are members of the M13 peptidase family (neprilysin (NEP, NEP2 and the endothelin converting enzymes (ECE-1 and -2. A distinct metallopeptidase, insulin-degrading enzyme (IDE, also contributes to A? degradation in the brain. The ADE family currently embraces more than 20 members, both membrane-bound and soluble, and of differing cellular locations. NEP plays an important role in brain function terminating neuropeptide signals. Its decrease in specific brain areas with age or after hypoxia, ischaemia or stroke contribute significantly to the development of AD pathology. The recently discovered mechanism of epigenetic regulation of NEP (and other genes by the APP intracellular domain (AICD and its dependence on the cell type and APP isoform expression suggest possibilities for selective manipulation of NEP gene expression in neuronal cells. We have also observed that another amyloid-clearing protein, namely transthyretin (TTR, is also regulated in the neuronal cell by a mechanism similar to NEP. Dependence of amyloid clearance proteins on histone deacetylases and the ability of HDAC inhibitors to up-regulate their expression in the brain opens new avenues for developing preventive strategies in AD.

Anthony J Turner

2014-09-01

344

Expression of serum amyloid A4 in human trophoblast-like choriocarcinoma cell lines and human first trimester/term trophoblast cells  

OpenAIRE

Trophoblast invasion into uterine tissues represents a hallmark of first trimester placental development. As expression of serum amyloid A4 (SAA4) occurs in tumorigenic and invasive tissues we here investigated whether SAA4 is present in trophoblast-like human AC1-M59/Jeg-3 cells and trophoblast preparations of human first trimester and term placenta. SAA4 mRNA was expressed in non-stimulated and cytokine-treated AC1-M59/Jeg-3 cells. In purified trophoblast cells SAA4 mRNA expression was upre...

Rossmann, C.; Hammer, A.; Koyani, C. N.; Kovacevic, A.; Siwetz, M.; Desoye, G.; Poehlmann, T. G.; Markert, U. R.; Huppertz, B.; Sattler, W.; Malle, E.

2014-01-01

345

Differential Associations of Serum Amyloid A and Pentraxin-3 with Allele-Specific Lipoprotein(a) Levels in African Americans and Caucasians  

OpenAIRE

Lipoprotein(a) [Lp(a)] is a CVD risk factor, where inflammation impacts levels differentially across ethnicity. We investigated the effect of systemic [serum amyloid A (SAA)] and vascular [pentraxin-3 (PTX-3)] inflammation on Lp(a) levels across different apo(a) sizes in a bi-ethnic population. Lp(a) and allele-specific apo(a) levels, apo(a) sizes, SAA and PTX-3 levels were determined in 336 Caucasians and 224 African Americans. We dichotomized subjects into 2 groups using the respective medi...

Enkhmaa, Byambaa; Anuurad, Erdembileg; Ozturk, Zeynep; Zhang, Wei; Pearson, Thomas A.; Berglund, Lars

2011-01-01

346

Functional Amyloids Signal Their Arrival  

OpenAIRE

Amyloids have traditionally been associated with misfolded protein aggregates and debilitating neurodegenerative diseases. However, a growing number of functional amyloids have now been described that demonstrate that amyloid formation can be an integral part of normal cellular physiology. Functional amyloid production is highly regulated, and the resulting fibers serve a variety of roles for the cells that produce them. A new role for amyloid as storage reservoirs for peptide hormones within...

Badtke, Matthew P.; Hammer, Neal D.; Chapman, Matthew R.

2009-01-01

347

Blood serum components and serum protein test of Hybro-PG broilers of different ages  

Directory of Open Access Journals (Sweden)

Full Text Available Blood serum samples of HYBRO PG broilers were analyzed, with 30 samples collected from 21-day-old broilers (G1, 30 from 35-day-old birds (G2, and 30 from 42-day-old birds (G3, with the aim of establishing normal values of some blood serum parameters. The activities of the enzymes gamma-glutamyl-transferase (GGT, aspartate aminotransferase (AST, creatine kinase (CK, alkaline phosphatase (ALP, and lactate dehydrogenase (LDH, serum levels of total calcium, calcium ion, phosphorus, sodium, potassium, magnesium, chlorides, creatinine, uric acid, triglycerides, cholesterol, total protein, albumin, total and indirect and direct bilirubin, and electrophoretic profile of serum proteins in acrylamide (SDS-PAGE and agarose gel were determined. There was no influence of age on total bilirubin and albumin levels. All the other evaluated parameters presented differences in at least one age group. Protein electrophoretic profile also changed as a function of age. The obtained results can be considered as normal for the studied ages, and therefore be used as references for the interpretation of laboratory exams of broilers of this genetic line in the evaluated ages.

PRL Silva

2007-12-01

348

Neprilysin Overexpression Inhibits Plaque Formation But Fails to Reduce Pathogenic A? Oligomers and Associated Cognitive Deficits in Human Amyloid Precursor Protein Transgenic Mice  

OpenAIRE

The accumulation of amyloid-? (A?) peptides in the brain of patients with Alzheimer’s disease (AD) may arise from an imbalance between A? production and clearance. Overexpression of the A?-degrading enzyme neprilysin in brains of human amyloid precursor protein (hAPP) transgenic mice decreases overall A? levels and amyloid plaque burdens. Because AD-related synaptic and cognitive deficits appear to be more closely related to A? oligomers than to plaques, it is important to determine i...

Meilandt, William J.; Cisse, Moustapha; Ho, Kaitlyn; Wu, Tiffany; Esposito, Luke A.; Scearce-levie, Kimberly; Cheng, Irene H.; Yu, Gui-qiu; Mucke, Lennart

2009-01-01

349

The expression of the Alzheimer’s Amyloid Precursor Protein-like gene is regulated by developmental timing microRNAs and their targets in Caenorhabditis elegans  

OpenAIRE

Alzheimer’s Disease (AD) is a neurodegenerative disorder characterized by the accumulation of dense plaques in the brain, resulting in progressive dementia. A major plaque component is the ?-amyloid peptide, which is a cleavage product of the amyloid precursor protein (APP). Studies of dominant inheritable familial AD support the hypothesis that APP is critical for AD development. On the other hand, the pathogenesis of amyloid plaque deposition in AD is thought to be the result of age-rela...

Niwa, Ryusuke; Zhou, Feng; Li, Chris; Slack, Frank J.

2008-01-01

350

Amyloid plaques, neurofibrillary tangles and neuronal loss in brains of transgenic mice overexpressing a C-terminal fragment of human amyloid precursor protein.  

Science.gov (United States)

Alzheimer's disease (AD) affects more than 30% of people over 80 years of age. The aetiology and pathogenesis of this progressive dementia is poorly understood, but symptomatic disease is associated histopathologically with amyloid plaques, neurofibrillary tangles and neuronal loss primarily in the temporal lobe and neocortex of the brain. The core of the extracellular plaque is a derivative of the amyloid precursor protein (APP), referred to as beta/A4, and contains the amino-acid residues 29-42 that are normally embedded in the membrane-spanning region of the precursor. The cellular source of APP and the relationship of its deposition to the neuropathology of AD is unknown. To investigate the relationship between APP overexpression and amyloidogenesis, we have developed a vector to drive expression specifically in neurons of a C-terminal fragment of APP that contains the beta/A4 region, and have used a transgenic mouse system to insert and express this construct. We report here that overexpression of this APP transgene in neurons is sufficient to produce extracellular dense-core amyloid plaques, neurofibrillary tangles and neuronal degeneration similar to that in the AD brain. PMID:1793460

Kawabata, S; Higgins, G A; Gordon, J W

1991-12-12

351

Soluble amyloid precursor protein-? rescues age-linked decline in neural progenitor cell proliferation.  

Science.gov (United States)

Neurogenesis is thought to play a role in cognitive function and hippocampal plasticity. Previous studies suggest that neurogenesis declines with aging. However, the onset and mechanism of declined neurogenesis are not fully elucidated. Here we show that the major decline in neurogenesis takes place during adulthood, before aging. Decline in neurogenesis takes place in the subgranular layer of the dentate gyrus and in the subventricular zone, and is primarily due to a reduced number of fast-proliferating neural progenitor cells. Importantly, this decline can be rescued by intraventricular injection of recombinant soluble amyloid precursor protein (sAPP?), which regulates neural progenitor cell proliferation in the adult brain. The counterpart, sAPP?, a product of the amyloidogenic cleavage pathway of amyloid precursor protein, fails to exhibit a proliferative effect in vitro and in vivo, in equimolar concentrations to sAPP?. These observations suggest that adulthood is an appropriate time window for an intervention that upregulates neurogenesis, such as enhancement of sAPP? levels, for the prevention of declining brain plasticity and cognitive function. PMID:23683827

Demars, Michael P; Hollands, Carolyn; Zhao, Kai Da Tommy; Lazarov, Orly

2013-10-01

352

Acute ER stress regulates amyloid precursor protein processing through ubiquitin-dependent degradation.  

Science.gov (United States)

Beta-amyloid (A?), a major pathological hallmark of Alzheimer's disease (AD), is derived from amyloid precursor protein (APP) through sequential cleavage by ?-secretase and ?-secretase enzymes. APP is an integral membrane protein, and plays a key role in the pathogenesis of AD; however, the biological function of APP is still unclear. The present study shows that APP is rapidly degraded by the ubiquitin-proteasome system (UPS) in the CHO cell line in response to endoplasmic reticulum (ER) stress, such as calcium ionophore, A23187, induced calcium influx. Increased levels of intracellular calcium by A23187 induces polyubiquitination of APP, causing its degradation. A23187-induced reduction of APP is prevented by the proteasome inhibitor MG132. Furthermore, an increase in levels of the endoplasmic reticulum-associated degradation (ERAD) marker, E3 ubiquitin ligase HRD1, proteasome activity, and decreased levels of the deubiquitinating enzyme USP25 were observed during ER stress. In addition, we found that APP interacts with USP25. These findings suggest that acute ER stress induces degradation of full-length APP via the ubiquitin-proteasome proteolytic pathway. PMID:25740315

Jung, Eun Sun; Hong, HyunSeok; Kim, Chaeyoung; Mook-Jung, Inhee

2015-01-01

353

Antimicrobial activity of peptides derived from human ß-amyloid precursor protein.  

Science.gov (United States)

Antimicrobial peptides are important effector molecules of the innate immune system. Here, we describe that peptides derived from the heparin-binding disulfide-constrained loop region of human ß-amyloid precursor protein are antimicrobial. The peptides investigated were linear and cyclic forms of NWCKRGRKQCKTHPH (NWC15) as well as the cyclic form comprising the C-terminal hydrophobic amino acid extension FVIPY (NWCKRGRKQCKTHPHFVIPY; NWC20c). Compared with the benchmark antimicrobial peptide LL-37, these peptides efficiently killed the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, the Gram-positive Staphylococcus aureus and Bacillus subtilis, and the fungi Candida albicans and Candida parapsilosis. Correspondingly, fluorescence and electron microscopy demonstrated that the peptides caused defects in bacterial membranes. Analogously, the peptides permeabilised negatively charged liposomes. Despite their bactericidal effect, the peptides displayed very limited hemolytic activities within the concentration range investigated and exerted very small membrane permeabilising effects on human epithelial cells. The efficiency of the peptides with respect to bacterial killing and liposome membrane leakage was in the order NWC20c?>?NWC15c?>?NWC15l, which also correlated to the adsorption density for these peptides at the model lipid membrane. Thus, whereas the cationic sequence is a minimum determinant for antimicrobial action, a constrained loop-structure as well as a hydrophobic extension further contributes to membrane permeabilising activity of this region of amyloid precursor protein. PMID:22249992

Papareddy, Praveen; Mörgelin, Matthias; Walse, Björn; Schmidtchen, Artur; Malmsten, Martin

2012-03-01

354

Mitochondrial ?-secretase participates in the metabolism of mitochondria-associated amyloid precursor protein.  

Science.gov (United States)

Intracellular amyloid-? peptide (A?) has been implicated in the pathogenesis of Alzheimer's disease (AD). Mitochondria were found to be the target both for amyloid precursor protein (APP) that accumulates in the mitochondrial import channels and for A? that interacts with several proteins inside mitochondria and leads to mitochondrial dysfunction. Here, we have studied the role of mitochondrial ?-secretase in processing different substrates. We found that a significant proportion of APP is associated with mitochondria in cultured cells and that ?-secretase cleaves the shedded C-terminal part of APP identified as C83 associated with the outer membrane of mitochondria (OMM). Moreover, we have established the topology of the C83 in the OMM and found the APP intracellular domain (AICD) to be located inside mitochondria. Our data show for the first time that APP is a substrate for the mitochondrial ?-secretase and that AICD is produced inside mitochondria. Thus, we provide a mechanistic view of the mitochondria-associated APP metabolism where AICD, P3 peptide and potentially A? are produced locally and may contribute to mitochondrial dysfunction in AD. PMID:20833873

Pavlov, Pavel F; Wiehager, Birgitta; Sakai, Jun; Frykman, Susanne; Behbahani, Homira; Winblad, Bengt; Ankarcrona, Maria

2011-01-01

355

A study of serum zinc, copper, magnesium, proteins and enzyme superoxide dismutase in psoriasis  

OpenAIRE

Serum zinc, copper, magnesium, protein and enzyme superoxide dismutase were estimated in 50 cases of psoriasis and 40 normal healthy controls. Serum zinc, copper, magnesium were estimated using atomic absorption spectrophotometer (Shimadzu 646). Proteins were estimated by colorimetric methods and enzyme superoxide dismutase was estimated by Marklund and Marklund method. Serum zinc, magnesium, total proteins and albumin were significantly decreased whereas, serum copper and serum SOD were sign...

Madadi A; Sethi N; Bhandari S

1994-01-01

356

The c-Abl tyrosine kinase phosphorylates the Fe65 adaptor protein to stimulate Fe65/amyloid precursor protein nuclear signaling.  

OpenAIRE

The amyloid precursor protein (APP) is proteolytically processed to release a C-terminal domain that signals to the nucleus to regulate transcription of responsive genes. The APP C terminus binds to a number of phosphotyrosine binding (PTB) domain proteins and one of these, Fe65, stimulates APP nuclear signaling. Fe65 is an adaptor protein that contains a number of protein-protein interaction domains. These include two PTB domains, the second of which binds APP, and a ...

Mcloughlin, Declan

2004-01-01

357

Strong tranthyretin immunostaining, potential pitfall in cardiac amyloid typing  

Science.gov (United States)

Although systemic amyloidosis commonly presents with renal disease, cardiac involvement usually determines the patient's prognosis. Cardiac involvement is seen in AL and transthyretin amyloidosis. Distinguishing between these is critical because prognosis and treatment differ. Our study demonstrates the unreliability of transthyretin immunostaining in subtyping cardiac amyloid. Between January 2003 and August 2010, we retrieved 229 native endomyocardial biopsies, 24 had amyloid. Immunohistochemistry for kappa, lambda, transthyretin and serum amyloid A protein were performed on formalin fixed paraffin-embedded sections. Staining was graded as weak (trace to 1+); or strong (2 to 3+). Mass spectrometry (MS) based proteomic typing of microdissected amyloid material was performed on selected cases. Fifteen of the patients had monoclonal gammopathy/plasma cell dyscrasia with cardiac amyloid. Eight of them (53%) showed strong transthyretin staining in the cardiac amyloid deposits. MS was performed in five out of these eight biopsies, and all five revealed AL type amyloid. Two of these five AL amyloid biopsies did not even have concomitant strong staining for the appropriate light chain. Among the 15 cases with plasma cell dyscrasia, only seven biopsies showed strong staining for the corresponding monoclonal light chain. Strong false positive immunostaining for transthyretin in cardiac amyloid is a potential pitfall, augmented by the frequent lack of staining for immunoglobulin light chains. Therefore, the presence of amyloid in the cardiac biopsy should prompt a search for plasma cell dyscrasia irrespective of transthyretin staining. Confirmation with MS should be sought particularly if there is any discrepancy between kappa/lambda staining and serum immunofixation results. PMID:21945954

Satoskar, Anjali A.; Efebera, Yvonne; Hasan, Ayesha; Brodsky, Sergey; Nadasdy, Gyongyi; Dogan, Ahmet; Nadasdy, Tibor

2014-01-01

358

Amyloid precursor protein binding protein Fe65 is cleaved by caspases during DNA damage-induced apoptosis.  

Science.gov (United States)

Caspases cleave several cellular proteins to execute cell death by apoptosis. The identification of novel substrates of caspases could provide an important clue for elucidation of new apoptosis signaling pathways. In this study, we tested whether an amyloid precursor protein (APP) binding protein Fe65 is proteolytically degraded in neuronal cell death by apoptosis, using a neuron-like cell line, human neuroblastoma SH-SY5Y cells. When treated with DNA damaging agents, etoposide (ETP) and camptothecin (CPT), SH-SY5Y cells underwent apoptosis in a dose-dependent manner. Interestingly, Fe65 (97 kDa) was cleaved to a 65 kDa product during DNA damage-induced apoptosis. Furthermore, the cleavage of Fe65 was accompanied by activation of caspases-9 and -3. The restriction cleavage of Fe65 was completely suppressed by the treatment with a pan-caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp(OMe) fluoromethylketone (z-VAD-fmk). These results reveal the restriction cleavage of Fe65 by caspases during DNA damage-induced apoptosis. Since Fe65 has been shown to suppress APP processing to amyloid ? (A?) production, our findings may provide a new insight into the molecular mechanism by which DNA damage induces A? production and subsequent neuronal cell death in Alzheimer's disease (AD). PMID:21415543

Saeki, Kazunori; Nose, Yasuyo; Hirao, Nobukuni; Takasawa, Ryoko; Tanuma, Sei-Ichi

2011-01-01

359

APL-1, the Alzheimer’s Amyloid Precursor Protein in Caenorhabditis elegans, Modulates Multiple Metabolic Pathways Throughout Development  

OpenAIRE

Mutations in the amyloid precursor protein (APP) gene or in genes that process APP are correlated with familial Alzheimer’s disease (AD). The biological function of APP remains unclear. APP is a transmembrane protein that can be sequentially cleaved by different secretases to yield multiple fragments, which can potentially act as signaling molecules. Caenorhabditis elegans encodes one APP-related protein, APL-1, which is essential for viability. Here, we show that APL-1 signaling is depende...

Ewald, Collin Y.; Raps, Daniel A.; Li, Chris

2012-01-01

360

Gel Formation in Protein Amyloid Aggregation: A Physical Mechanism for Cytotoxicity  

OpenAIRE

Amyloid fibers are associated with disease but have little chemical reactivity. We investigated the formation and structure of amyloids to identify potential mechanisms for their pathogenic effects. We incubated lysozyme 20 mg/ml at 55C and pH 2.5 in a glycine-HCl buffer and prepared slides on mica substrates for examination by atomic force microscopy. Structures observed early in the aggregation process included monomers, small colloidal aggregates, and amyloid fibers. Amyloid fibers were ob...

Woodard, Daniel; Bell, Dylan; Tipton, David; Durrance, Samuel; Cole, Lisa; Li, Bin; Xu, Shaohua

2014-01-01

361

Interaction of molybdenum with blood serum proteins in vitro  

International Nuclear Information System (INIS)

The interaction of pentavalent and hexavalent 99Mo compounds with rat and human serum was monitored in vitro by paper electrophoresis after incubation for one hour at 370C. Hexavalent 99Mo is not capable of interaction and, via sulfur ligands, forms unstable and unspecific bonds to the whole spectrum of serum proteins, in particular to albumin. Pentavalent 99Mo binds strongly to alpha-2-macroglobulin in a ratio of 2 : 1; according to the nature of the ligand, it forms somewhat unstable bonds to albumin, beta-1-globulin and gamma-2-globulin. (author)

362

Binding of neptunium to serum proteins in vitro  

International Nuclear Information System (INIS)

The biological fate of neptunium compounds has received little study in the past. Moreover, interpretation of the data from past animal studies is also complicated because of the use of large masses of Np and unknown chemical forms. In this study, picogram quantities of well-characterized solutions of 239Np were incubated with canine serum and the resultant mixture characterized by gel chromatography, protein precipitation using trichloroacetic acid, dialysis and ultrafiltration. Results obtained using pure Np(V) solutions indicate that about half of the Np was bound to protein; the proteins to which the Np was bound were either quite large (MW > 300,000 daltons) or quite small (MW < 5000 daltons). Work is continuing to determine the effect of valence and mass on Np-serum interactions

363

How do membranes initiate Alzheimer's Disease? Formation of toxic amyloid fibrils by the amyloid ?-protein on ganglioside clusters.  

Science.gov (United States)

Alzheimer's disease (AD), a severe neurodegenerative disorder, causes more than half of dementia cases. According to the popular "A? hypothesis" to explain the mechanism of this disease, amyloid ?-peptides (A?) of 39-43 amino acid residues aggregate and deposit onto neurons, igniting the neurotoxic cascade of the disease. Therefore, researchers studying AD would like to elucidate the mechanisms by which essentially water-soluble but hydrophobic A? aggregates under pathological conditions. Most researchers have investigated the aggregation of A? in aqueous solution, and they concluded that the final aggregation product, the amyloid fibrils, were less toxic than the component peptide oligomers. They consequently shifted their interests to more toxic "soluble oligomers", structures that form as intermediates or off-pathway products during the aggregation process. Some researchers have also investigated artificial oligomers prepared under nonphysiological conditions. In contrast to these "in solution" studies, we have focused on "membrane-mediated" amyloidogenesis. In an earlier study, other researchers identified a specific form of A? that was bound to monosialoganglioside GM1, a sugar lipid, in brains of patients who exhibited the early pathological changes associated with AD. This Account summarizes 15 years of our research on this topic. We have found that A? specifically binds to GM1 that occurs in clusters, but not when it is uniformly distributed. Clustering is facilitated by cholesterol. Upon binding, A? changes its conformation from a random coil to an ?-helix-rich structure. A CH-? interaction between the aromatic side chains of A? and carbohydrate moieties appended to GM1 appears to be important for binding. In addition, as A? accumulates and reaches its first threshold concentration (A?/GM1 = ?0.013), aggregated ?-sheets of ?15 molecules appear and coexist with the helical form. However, this ?-structure is stable and does not form larger aggregates. When the disease progresses further and the A?/GM1 ratio exceeds ?0.044, the ?-structure converts to a second ?-structure that can seed aggregates. The seed recruits monomers from the aqueous phase to form toxic amyloid fibrils that have larger surface hydrophobicity and can contain antiparallel ?-sheets. In contrast, amyloid fibrils formed in aqueous solution are less toxic and have parallel ?-sheets. The less polar environments of GM1 clusters play an important role in the formation of these toxic fibrils. Membranes that contain GM1 clusters not only accelerate the aggregation of A? by locally concentrating A? molecules but also generate amyloid fibrils with unique structures and significant cytotoxicity. The inhibition of this aggregation cascade could be a promising strategy for the development of AD-modulating therapies. PMID:25029558

Matsuzaki, Katsumi

2014-08-19

364

Increased soluble amyloid-? peptide and memory deficits in amyloid model mice overexpressing the low-density lipoprotein receptor-related protein  

OpenAIRE

Amyloid-? peptide (A?) is central to the pathogenesis of Alzheimer's disease, and the low-density lipoprotein receptor-related protein (LRP) has been shown to alter A? metabolism in vitro. Here, we show that overexpression of a functional LRP minireceptor in the brain of PDAPP mice results in age-dependent increase of soluble brain A?, with no changes in A? plaque burden. Importantly, soluble brain A? was found to be primarily in the form of monomers/dimers and to be highly correlated w...

Zerbinatti, Celina V.; Wozniak, David F.; Cirrito, John; Cam, Judy A.; Osaka, Hiroshi; Bales, Kelly R.; Zhuo, Min; Paul, Steven M.; Holtzman, David M.; Bu, Guojun

2004-01-01

365

Characterization of cDNA encoding a human sperm membrane protein related to A4 amyloid protein  

International Nuclear Information System (INIS)

A rat testis ?gt11 cDNA library was screened with a monoclonal antibody raised against a human sperm membrane protein designated YWK-II. A clone was found with a cDNA insert composed of 1837 base pairs that contained an open reading frame coding for 191 amino acid residues. The deduced polypeptide contained a segment with high homology to the transmembrane-cytoplasmic domains of the A4 amyloid protein found in brain plaques of Alzheimer disease patients. A sequence of basic amino acid residues, Arg-Lys-Arg, was found instead of Lys-Lys-Lys at the probable membrane-cytoplasmic junction that may be a unique property of sperm membrane proteins

366

Phosphorylation as conformational switch from the native to amyloid state: trp-cage as a protein aggregation model.  

Science.gov (United States)

The 20 residue long Trp-cage miniprotein is an excellent model for both computational and experimental studies of protein folding and stability. Recently, great attention emerged to study disease-related protein misfolding, aggregation, and amyloid formation, with the aim of revealing their structural and thermodynamic background. Trp-cage is sensitive to both environmental and structure-modifying effects. It aggregates with ease upon structure destabilization, and thus it is suitable for modeling aggregation and amyloid formation. Here, we characterize the amyloid formation of several sequence modified and side-chain phosphorylated Trp-cage variants. We applied NMR, circular dichroism (CD) and Fourier transform infrared (FTIR) spectroscopies, molecular dynamics (MD) simulations, and transmission electron microscopy (TEM) in conjunction with thioflavin-T (ThT) fluorescence measurements to reveal the structural consequences of side-chain phosphorylation. We demonstrate that the native fold is destabilized upon serine phosphorylation, and the resultant highly dynamic structures form amyloid-like ordered aggregates with high intermolecular ?-structure content. The only exception is the D9S(P) variant, which follows an alternative aggregation process by forming thin fibrils, presenting a CD spectrum of PPII helix, and showing low ThT binding capability. We propose a complex aggregation model for these Trp-cage miniproteins. This model assumes an additional aggregated state, a collagen triple helical form that can precede amyloid formation. The phosphorylation of a single serine residue serves as a conformational switch, triggering aggregation, otherwise mediated by kinases in cell. We show that Trp-cage miniprotein is indeed a realistic model of larger globular systems of composite folding and aggregation landscapes and helps us to understand the fundamentals of deleterious protein aggregation and amyloid formation. PMID:25625571

Kardos, József; Kiss, Bence; Micsonai, András; Rovó, Petra; Menyhárd, Dóra K; Kovács, János; Váradi, Györgyi; Tóth, Gábor K; Perczel, András

2015-02-19

367

Identification of a Serum amyloid A gene and the association of SNPs with Vibrio-resistance and growth traits in the clam Meretrix meretrix.  

Science.gov (United States)

Serum amyloid A (SAA), an acute response protein as well as an apolipoprotein, is considered to play crucial roles in both innate immunity and lipid metabolism. In this study, a SAA gene (MmSAA) was identified in the clam Meretrix meretrix. The full length DNA of MmSAA was 1407bp, consisting of three exons and two introns. The distribution of MmSAA in clam tissues was examined with the highest expression in hepatopancreas. In response to the Vibrio parahaemolyticus challenge, MmSAA mRNA showed significantly higher expression at 24 h post-challenge in experimental clams (P single nucleotide polymorphisms (SNPs) in the DNA partial sequence of MmSAA were discovered and examined for their association with Vibrio-resistance and growth traits, respectively. The single SNP association analysis indicated that five single SNPs (g.42, g.72, g.82, g.147 and g.165) were significantly associated with Vibrio-resistance (P < 0.05). Haplotype analysis produced additional support for association with the Chi-square values 6.393 (P = 0.012). Among the five selected SNPs, the effect of a missense mutation (g.82, A ? G) was detected by site-directed mutagenesis with fusion expression of protein assay, and the result showed that the recombinant plasmids containing wild-type pET30a-MmSAA had more inhibition effect than the mutant ones on the growth rate of the host bacteria. In addition, four growth traits of the clams in 09G3SPSB population were recorded and the SNP g.176 was found to be significantly associated with the growth traits with the Global score value 0.790 (P = 0.015). Our findings suggested that common genetic variation in MmSAA might contribute to the risk of susceptibility to Vibrio infection and might be associated with the growth traits in the clams M. meretrix, and more works are still needed to validate these SNPs as potential markers for actual selective breeding. PMID:25602707

Zou, Linhu; Liu, Baozhong

2015-04-01

368

Dual roles of the transmembrane protein p23/TMP21 in the modulation of amyloid precursor protein metabolism  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Alzheimer's disease (AD is characterized by cerebral deposition of ?-amyloid (A? peptides. A? is released from ectodomain cleaved amyloid precursor protein (APP via intramembranous proteolysis by ?-secretase, a complex consisting of presenilin and a few other proteins. p23/TMP21, a member of the p24 family type I transmembrane proteins, was recently identified as a presenilin complex component capable of modulating ?-secretase cleavage. The p24 family proteins form oligomeric complexes and regulate vesicular trafficking in the early secretory pathway, but their role in APP trafficking has not been investigated. Results Here, we report that siRNA-mediated depletion of p23 in N2a neuroblastoma and HeLa cells produces concomitant knockdown of additional p24 family proteins and increases secretion of sAPP. Furthermore, intact cell and cell-free A? production increases following p23 knockdown, similar to data reported earlier using HEK293 cells. However, we find that p23 is not present in mature ?-secretase complexes isolated using an active-site ?-secretase inhibitor. Depletion of p23 and expression of a familial AD-linked PS1 mutant have additive effects on A?42 production. Knockdown of p23 expression confers biosynthetic stability to nascent APP, allowing its efficient maturation and surface accumulation. Moreover, immunoisolation analyses show decrease in co-residence of APP and the APP adaptor Mint3. Thus, multiple lines of evidence indicate that p23 function influences APP trafficking and sAPP release independent of its reported role in ?-secretase modulation. Conclusion These data assign significance to p24 family proteins in regulating APP trafficking in the continuum of bidirectional transport between the ER and Golgi, and ascribe new relevance to the regulation of early trafficking in AD pathogenesis.

Wieland Felix T

2007-02-01

369

Presenile dementia and cerebral haemorrhage linked to a mutation at codon 692 of the ?-amyloid precursor protein gene  

OpenAIRE

Several families with an early-onset form of familial Alzheimer's disease have been found to harbour mutations at a specific codon (717) of the gene for the beta-amyloid precursor protein (APP) on chromosome 21. We now report, a novel base mutation in the same exon of the APP gene which co-segregates in one family with presenile dementia and cerebral haemorrhage due to cerebral amyloid angiopathy. The mutation results in the substitution of alanine into glycine at codon 692. These results sug...

Hendriks, L.; Duijn, C. M.; Cras, P.; Cruts, M.; Hul, W.; Harskamp, F.; Warren, A.; Mcinnis, M. G.; Antonarakis, S. E.; Martin, J-j; Broeckhoven, C.; Hofman, A.

1992-01-01

370

Sortilin and SorLA Display Distinct Roles in Processing and Trafficking of Amyloid Precursor Protein  

DEFF Research Database (Denmark)

The development and progression of Alzheimer's disease is linked to excessive production of toxic amyloid-? peptide, initiated by ?-secretase cleavage of the amyloid precursor protein (APP). In contrast, soluble APP? (sAPP?) generated by the ?-secretase is known to stimulate dendritic branching and enhance synaptic function. Regulation of APP processing, and the shift from neurotrophic to neurotoxic APP metabolism remains poorly understood, but the cellular localization of APP and its interaction with various receptors is considered important. We here identify sortilin as a novel APP interaction partner. Like the related APP receptor SorLA, sortilin is highly expressed in the CNS, but whereas SorLA mainly colocalizes with APP in the soma, sortilin interacts with APP in neurites. The presence of sortilin promotes ?-secretase cleavage of APP, unlike SorLA, which inhibits the generation of all soluble products. Also, sortilin and SorLA both bind and mediate internalization of sAPP but to different cellular compartments. The interaction involves the 6A domain of APP, present in both neuronal and non-neuronal APP isoforms. This is important as sAPP receptors described so far only bind the non-neuronal isoforms, leaving SorLA and sortilin as the only receptors for sAPP generated by neurons. Together, our findings establish sortilin, as a novel APP interaction partner that influences both production and cellular uptake of sAPP.

Gustafsen, Camilla; Glerup, Simon

2013-01-01

371

Serum protein concentrations in calves with experimentally induced pneumonic pasteurellosis  

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Full Text Available Ten healthy 2 to 4-week-old Holstein calves were randomly allotted into control and infected groups. Control calves (n=5 were inoculated intrabronchially with 5ml of Dulbecco's phosphate-buffered saline solution (DPBSS. Infected calves (n=5 were inoculated intrabronchially with 5x10(9 log-phase Mannheimia haemolytica organisms suspended in 5ml of DPBSS. Blood samples were obtained 15 minutes before and one, two, four and six hours after inoculation. Serum protein concentrations were determined by means of sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Serum concentrations of proteins with molecular weights of 125,000 D (ceruloplasmin, 60,000 D (a 1-antitrypsin, 45,000 D (haptoglobin, and 40,000 D (acid glycoprotein were significantly increased in calves with pneumonic pasteurellosis, compared with concentrations in control calves. Results indicate that acute phase proteins increase more rapidly after the onset of inflammation than previously thought. Measurement of serum protein concentrations may be useful in monitoring the progression of the induced pneumonic pasteurellosis in calves.

Fagliari J.J.

2003-01-01

372

Effect of stent-assisted angioplasty on cognitive status and serum levels of amyloid beta in patients with intracranial and/or extracranial artery stenosis  

Directory of Open Access Journals (Sweden)

Full Text Available Liandong Zhao,1 Ying Zhao,1 Haijun Zhang2 1Department of Neurology, The Second People’s Hospital of Huai’an and The Affiliated Huai’an Hospital of Xuzhou Medical College, Huai’an, Jiangsu, 2Department of Oncology, Zhongda Hospital, Medical School, Southeast University, Nanjing, People’s Republic of China Aim: The study reported here aimed to examine how stent-assisted angioplasty affects cognitive status and serum levels of amyloid betas (A?s 1-40 and 1-42 in patients with cerebral arterial stenosis.Methods: Patients with cerebral arterial stenosis were given stent-assisted angioplasty plus conventional treatment (stent-assisted angioplasty group or conventional treatment alone (control group. Cognitive status and A?1-40 and A?1-42 serum levels were determined before treatment and at 4 and 8 weeks after treatment.Results: At 4 weeks after treatment, cognitive status in patients with stent-assisted angioplasty had clearly improved. A?1-42 serum levels changed insignificantly in all patients. However, A?1-40 serum levels and A?1-40/A?1-42 ratio decreased further in patients with stent-assisted angioplasty than in patients who received conventional treatment (controls. Eight weeks after treatment, cognitive status in patients who had undergone stent-assisted angioplasty were continuing to improve, A?1-42 serum levels had begun to increase dramatically, and A?1-40 serum levels and A?1-40/A?1-42 ratio had declined further.Conclusion: Stent-assisted angioplasty could improve cognitive status and decrease A?1-40 serum levels and A?1-40/A?1-42 ratio. Keywords: arterial stenosis, Alzheimer’s disease, A?1-40, A?1-42, A?1-40/A?1-42 ratio

Zhao L

2015-02-01

373

{sup 99m}Tc-MAMA-chrysamine G, a probe for beta-amyloid protein of Alzheimer's disease  

Energy Technology Data Exchange (ETDEWEB)

Chrysamine G (CG), an analogue of Congo red, is known to bind in vitro to the {beta}-amyloid protein (A{beta} 10-43) and to homogenates of several regions of the brain of Alzheimer's disease (AD) patients. We synthesised a conjugate of 2-(acetamido)-CG with a bis-S-trityl protected monoamide-monoaminedithiol (MAMA-Tr{sub 2}) tetraligand, which was efficiently deprotected and labelled with a 75% yield with technetium-99m, to obtain {sup 99m}Tc-MAMA-CG. In mice, {sup 99m}Tc-MAMA-CG was cleared mainly by the hepatobiliary system, resulting in a fast blood clearance. Brain uptake of {sup 99m}Tc-MAMA-CG was low. Co-injection with the blood pool tracer iodine-125 human serum albumin ({sup 125}I-HSA) demonstrated a brain/blood activity ratio for {sup 99m}Tc-MAMA-CG that was significantly higher than that for {sup 125}I-HSA (t test for dependent samples, P<0.02), indicating the ability of {sup 99m}Tc-MAMA-CG to cross the blood-brain barrier. In vitro autoradiography demonstrated pronounced binding of {sup 99m}Tc-MAMA-CG to {beta}-amyloid deposits in autopsy sections of the parietal and occipital cortex of an AD patient as compared with controls. Adding 10 {mu}M Congo red during incubation displaced the binding of {sup 99m}Tc-MAMA-CG. Congo red staining and autoradiography identified the same lesions. {sup 99m}Tc-MAMA-CG seems to bind selectively to {beta}-amyloid deposition in human brain parenchyma and blood vessels in vitro and thus might be a lead compound for further development of a useful tracer agent for the in vivo diagnosis of Alzheimer's disease. (orig.)

Dezutter, N.A.; Groot, T.J. de; Bormans, G.M. [K.U. Leuven (Belgium). Lab. of Radiopharmaceutical Chemistry; Dom, R.J. [Department of Neuropathology, University Hospital Gasthuisberg, Leuven (Belgium); Verbruggen, A.M. [K.U. Leuven (Belgium). Lab. of Radiopharmaceutical Chemistry; U.Z. Gasthuisberg, Radiopharmacy, Leuven (Belgium)

1999-11-01

374

Interactions of pathological hallmark proteins: tubulin polymerization promoting protein/p25, beta-amyloid, and alpha-synuclein.  

Science.gov (United States)

The disordered tubulin polymerization promoting protein (TPPP/p25) was found to be co-enriched in neuronal and glial inclusions with ?-synuclein in Parkinson disease and multiple system atrophy, respectively; however, co-occurrence of ?-synuclein with ?-amyloid (A?) in human brain inclusions has been recently reported, suggesting the existence of mixed type pathologies that could result in obstacles in the correct diagnosis and treatment. Here we identified TPPP/p25 as an interacting partner of the soluble A? oligomers as major risk factors for Alzheimer disease using ProtoArray human protein microarray. The interactions of oligomeric A? with proteins involved in the etiology of neurological disorders were characterized by ELISA, surface plasmon resonance, pelleting experiments, and tubulin polymerization assay. We showed that the A?(42) tightly bound to TPPP/p25 (K(d) = 85 nm) and caused aberrant protein aggregation by inhibiting the physiologically relevant TPPP/p25-derived microtubule assembly. The pair-wise interactions of A?(42), ?-synuclein, and tubulin were found to be relatively weak; however, these three components formed soluble ternary complex exclusively in the absence of TPPP/p25. The aggregation-facilitating activity of TPPP/p25 and its interaction with A? was monitored by electron microscopy with purified proteins by pelleting experiments with cell-free extracts as well as by confocal microscopy with CHO cells expressing TPPP/p25 or amyloid. The finding that the interaction of TPPP/p25 with A? can produce pathological-like aggregates is tightly coupled with unusual pathology of the Alzheimer disease revealed previously; that is, partial co-localization of A? and TPPP/p25 in the case of diffuse Lewy body disease with Alzheimer disease. PMID:21832049

Oláh, Judit; Vincze, Orsolya; Virók, Dezsõ; Simon, Dóra; Bozsó, Zsolt; Tõkési, Natália; Horváth, István; Hlavanda, Emma; Kovács, János; Magyar, Anna; Sz?cs, Mária; Orosz, Ferenc; Penke, Botond; Ovádi, Judit

2011-09-30

375

A proteomic reference map for pig serum proteins as a prerequisite for diagnostic applications.  

OpenAIRE

A reference protein map for pig serum was set up using two-dimensional electrophoresis (2-DE). Thirty-nine protein chains or spots deriving from 26 different proteins were identified by immunological and mass spectrometric methods. Thus, the positions of most medium to higher abundance serum proteins could be determined on the 2-DE gels. The plasma protein fibrinogen was also included in our study. The overall pig protein pattern differs in some respect to serum/plasma maps of other mammalian...

Miller, I.; Wait, R.; Sipos, W.; Gemeiner, M.

2009-01-01

376

GENETIC CATHEPSIN B DEFICIENCY REDUCES ?-AMYLOID IN TRANSGENIC MICE EXPRESSING HUMAN WILD-TYPE AMYLOID PRECURSOR PROTEIN  

OpenAIRE

Neurotoxic ?-amyloid (A?) peptides participate in Alzheimer’s disease (AD); therefore, reduction of A? generated from APP may provide a therapeutic approach for AD. Gene knockout studies in transgenic mice producing human A? may identify targets for reducing A?. This study shows that knockout of the cathepsin B gene in mice expressing human wild-type APP (hAPPwt) results in substantial decrease of A?40 and A?42 by 67% in brain, and decreases levels of the C-terminal ?-secretase frag...

Hook, Vivian Y. H.; Kindy, Mark; Reinheckel, Thomas; Peters, Christoph; Hook, Gregory

2009-01-01

377

Mapping of the gene encoding the beta-amyloid precursor protein and its relationship to the Down syndrome region of chromosome 21.  

OpenAIRE

The gene encoding the beta-amyloid precursor protein has been assigned to human chromosome 21, as has a gene responsible for at least some cases of familial Alzheimer disease. Linkage studies strongly suggest that the beta-amyloid precursor protein and the product corresponding to familial Alzheimer disease are from two genes, or at least that several million base pairs of DNA separate the markers. The precise location of the beta-amyloid precursor protein gene on chromosome 21 has not yet be...

Patterson, D.; Gardiner, K.; Kao, F. T.; Tanzi, R.; Watkins, P.; Gusella, J. F.

1988-01-01

378

Ablation of Cellular Prion Protein Does Not Ameliorate Abnormal Neural Network Activity or Cognitive Dysfunction in the J20 Line of Human Amyloid Precursor Protein Transgenic Mice  

OpenAIRE

Previous studies suggested that the cellular prion protein (PrPc) plays a critical role in the pathogenesis of Alzheimer’s disease (AD). Specifically, amyloid-? (A?) oligomers were proposed to cause synaptic and cognitive dysfunction by binding to PrPc. To test this hypothesis, we crossed human amyloid precursor protein (hAPP) transgenic mice from line J20 onto a PrPc-deficient background. Ablation of PrPc did not prevent the premature mortality and abnormal neural network activity typica...

Cisse?, Moustapha; Sanchez, Pascal E.; Kim, Daniel H.; Ho, Kaitlyn; Yu, Gui-qiu; Mucke, Lennart

2011-01-01

379

Biotransformation of BMOV in the presence of blood serum proteins.  

Science.gov (United States)

The interaction of the potent anti-diabetic agent bis(maltolato)oxidovanadium(IV) (BMOV) with some proteins of blood serum was studied by EPR spectroscopy, pH-potentiometry and DFT calculations. The formation of cis-VO(ma)(2)(hTf), cis-VO(ma)(2)(HSA) and cis-VO(ma)(2)(IgG), their role in the biotransformation in vivo and the mechanism of transport of BMOV in blood are discussed. PMID:22094980

Sanna, Daniele; Bíró, Linda; Buglyó, Péter; Micera, Giovanni; Garribba, Eugenio

2012-01-01

380

MicroRNA-298 AND microRNA-328 REGULATE EXPRESSION OF MOUSE ?-AMYLOID PRECURSOR PROTEIN CONVERTING ENZYME 1*  

OpenAIRE

MicroRNAs (miRNAs) are key regulatory RNAs known to repress messenger RNA (mRNA) translation through recognition of specific binding sites (BS) located mainly in their 3? untranslated region (UTR). Loss of specific miRNA control of gene expression is thus expected to underlie serious genetic diseases. Intriguingly, previous post-mortem analyses showed higher ?-amyloid precursor protein converting enzyme (BACE) protein, but not mRNA, levels in the brain of patients that suffered from Alzhei...

Boissonneault, Vincent; Plante, Isabelle; Rivest, Serge; Provost, Patrick

2008-01-01

381

From differentiation to proliferation: The secretory amyloid precursor protein as a local mediator of growth in thyroid?epithelial?cells  

OpenAIRE

In various species, thyrotropin (TSH) is known to stimulate both differentiation and proliferation of thyroid follicle cells. This cell type has also been shown to express members of the Alzheimer amyloid precursor (APP) protein family and to release the secretory N-terminal domain of APP (sAPP) in a TSH-dependent fashion. In this study on binding to the cell surfaces, exogenously added recombinant sAPP stimulated phosphorylation mediated by mitogen-activated protein kinase and effectively ev...

Pietrzik, Claus Ulrich; Hoffmann, Jens; Sto?ber, Kai; Chen, Chun-yan; Bauer, Christoph; Otero, Deborah A. C.; Roch, Jean-marc; Herzog, Volker

1998-01-01

382

Egg white varnishes on ancient paintings: a molecular connection to amyloid proteins.  

Science.gov (United States)

For about 400 years, egg white was used to coat and protect paintings without detailed understanding of its molecular properties. A molecular basis is provided for its advantageous properties and one of its protective properties is demonstrated with oxygen transport behavior. Compared to the native secondary structure of ovalbumin in solution of circa 33% ?-helix and ?-sheet, attenuated total reflection-FTIR (ATR-FTIR) spectra showed a 73% decrease of ?-helix content and a 44% increase of ?-sheet content over eight days. The data suggest that the final coating of dissolved ovalbumin from egg white after long exposure to air, which is hydrophobic, comprises mostly ?-sheet content (ca. 50%), which is predicted to be the lowest-energy structure of proteins and close to that found in amyloid fibrils. Coating a synthetic polytetrafluoroethylene membrane with multiple layers of egg white decreased oxygen diffusion by 50% per layer with a total decrease of almost 100% for four layers. PMID:24838630

Imbrogno, Joseph; Nayak, Arpan; Sorci, Mirco; Belfort, Georges

2014-07-01

383

Cellular prion protein participates in amyloid-? transcytosis across the blood–brain barrier  

Science.gov (United States)

The blood–brain barrier (BBB) facilitates amyloid-? (A?) exchange between the blood and the brain. Here, we found that the cellular prion protein (PrPc), a putative receptor implicated in mediating A? neurotoxicity in Alzheimer's disease (AD), participates in A? transcytosis across the BBB. Using an in vitro BBB model, [125I]-A?1?40 transcytosis was reduced by genetic knockout of PrPc or after addition of a competing PrPc-specific antibody. Furthermore, we provide evidence that PrPc is expressed in endothelial cells and, that monomeric A?1?40 binds to PrPc. These observations provide new mechanistic insights into the role of PrPc in AD. PMID:22293988

Pflanzner, Thorsten; Petsch, Benjamin; André-Dohmen, Bettina; Müller-Schiffmann, Andreas; Tschickardt, Sabrina; Weggen, Sascha; Stitz, Lothar; Korth, Carsten; Pietrzik, Claus U

2012-01-01

384

Cellular prion protein participates in amyloid-? transcytosis across the blood-brain barrier.  

Science.gov (United States)

The blood-brain barrier (BBB) facilitates amyloid-? (A?) exchange between the blood and the brain. Here, we found that the cellular prion protein (PrP(c)), a putative receptor implicated in mediating A? neurotoxicity in Alzheimer's disease (AD), participates in A? transcytosis across the BBB. Using an in vitro BBB model, [(125)I]-A?(1-40) transcytosis was reduced by genetic knockout of PrP(c) or after addition of a competing PrP(c)-specific antibody. Furthermore, we provide evidence that PrP(c) is expressed in endothelial cells and, that monomeric A?(1-40) binds to PrP(c). These observations provide new mechanistic insights into the role of PrP(c) in AD. PMID:22293988

Pflanzner, Thorsten; Petsch, Benjamin; André-Dohmen, Bettina; Müller-Schiffmann, Andreas; Tschickardt, Sabrina; Weggen, Sascha; Stitz, Lothar; Korth, Carsten; Pietrzik, Claus U

2012-04-01

385

Intramembrane Proteolysis of ?-Amyloid Precursor Protein by ?-Secretase Is an Unusually Slow Process.  

Science.gov (United States)

Intramembrane proteolysis has emerged as a key mechanism required for membrane proteostasis and cellular signaling. One of the intramembrane-cleaving proteases (I-CLiPs), ?-secretase, is also intimately implicated in Alzheimer's disease, a major neurodegenerative disease and leading cause of dementia. High-resolution crystal structural analyses have revealed that I-CLiPs harbor their active sites buried deeply in the membrane bilayer. Surprisingly, however, the key kinetic constants of these proteases, turnover number kcat and catalytic efficiency kcat/KM, are largely unknown. By investigating the kinetics of intramembrane cleavage of the Alzheimer's disease-associated ?-amyloid precursor protein in vitro and in human embryonic kidney cells, we show that ?-secretase is a very slow protease with a kcat value similar to those determined recently for rhomboid-type I-CLiPs. Our results indicate that low turnover numbers may be a general feature of I-CLiPs. PMID:25762334

Kamp, Frits; Winkler, Edith; Trambauer, Johannes; Ebke, Amelie; Fluhrer, Regina; Steiner, Harald

2015-03-10

386

Cyclin-dependent Kinase 5 Phosphorylation of Familial Prion Protein Mutants Exacerbates Conversion into Amyloid Structure.  

Science.gov (United States)

Familial prion protein (PrP) mutants undergo conversion from soluble and protease-sensitive to insoluble and partially protease-resistant proteins. Cyclin-dependent kinase 5 (Cdk5) phosphorylation of wild type PrP (pPrP) at serine 43 induces a conversion of PrP into aggregates and fibrils. Here, we investigated whether familial PrP mutants are predisposed to Cdk5 phosphorylation and whether phosphorylation of familial PrP mutants increases conversion. PrP mutants representing three major familial PrP diseases and different PrP structural domains were studied. We developed a novel in vitro kinase reaction coupled with Thioflavin T binding to amyloid structure assay to monitor phosphorylation-dependent amyloid conversion. Although non-phosphorylated full-length wild type or PrP mutants did not convert into amyloid, Cdk5 phosphorylation rapidly converted these into Thioflavin T-positive structures following first order kinetics. Dephosphorylation partially reversed conversion. Phosphorylation-dependent conversion of PrP from ?-helical structures into ?-sheet structures was confirmed by circular dichroism. Relative to wild type pPrP, most PrP mutants showed increased rate constants of conversion. In contrast, non-phosphorylated truncated PrP Y145X (where X represents a stop codon) and Q160X mutants converted spontaneously into Thioflavin T-positive fibrils after a lag phase of over 20 h, indicating nucleation-dependent polymerization. Phosphorylation reduced the lag phase by over 50% and thus accelerated the formation of the nucleating event. Consistently, phosphorylated Y145X and phosphorylated Q160X exacerbated conversion in a homologous seeding reaction, whereas WT pPrP could not seed WT PrP. These results demonstrate an influence of both the N terminus and the C terminus of PrP on conversion. We conclude that post-translational modifications of the flexible N terminus of PrP can cause or exacerbate PrP mutant conversion. PMID:25572400

Rouget, Raphaël; Sharma, Gyanesh; LeBlanc, Andréa C

2015-02-27

387

Assessment of the nature interactions of ?-amyloid protein by a nanoprobe method.  

Science.gov (United States)

We present a method based on atomic force microscopy (AFM) to assess the work of adhesion between the interfaces of gold AFM tips functionalized with three peptides derived from ?-sheet breaker LPFFD [CLPFFD-NH2 (i0) and their isomers CDLPFF-NH2 (i1) and CLPDFF-NH2 (i2)], and the beta-amyloid protein (A?1-42). ?-Amyloid protein was deposited onto a highly oriented graphite (HOPG) surface as protofibrils and fibrils. The presence of the residues Leu (L), Phe (F), and Phe (F), which are also present in the native sequence, confirm that the peptides are able to bind to the aggregates of A?1-42 fibrils and protofibrils. Force of adhesion data were directly obtained from the maximum force on retraction, and the work of adhesion was calculated from the Jhonson-Kendall-Roberts model (JKR-Model). Both the polar and dispersive contributions to the surface energy of the peptides i0, i1, and i2, as well as A?1-42 fibrils and protofibrils, were determined by means of measuring the contact angle and using the two-fluid method. The macroscopic energies of the functionalized gold surfaces do not differ significantly between isomers, which confirms the similar nature of the peptides i0, i1, and i2 but suggests that the macroscopic measurements are not able to distinguish specific sequences. The nanoprobe reveals a typical adhesion work value associated with the interaction of protofibrils with i0 and i2; this value is three times higher than that of i1. The difference is attributed to the hydrophobic nature of protofibrils, the predominant exposition of hydrophobic residues of the peptides i0 and i2, with respect to i1, and the degree of functionalization. i0 and i2 presented a slight adhesion with A? fibrils, which is associated with the exposed hydrophilic groups of these fibrils (onto HOPG) compared to the protofibrils. However, i1 showed interaction with both A? fibrils and protofibrils. For this, we propose an explanation based on the fact that the peptide i1 locates itself adjacent to the gold surface of the probe, concealing their hydrophobic groups and therefore decreasing the probability of interaction with A? fibrils and protofibrils. The peptide-gold nano probe represents a useful tool to study the nanobiointeractions of functionalized nanoparticles with amyloid aggregates. PMID:25486322

Caballero, Leonardo; Mena, Juan; Morales-Alvarez, Aurora; Kogan, Marcelo J; Melo, Francisco

2015-01-13

388

Acute serum amyloid A induces migration, angiogenesis, and inflammation in synovial cells in vitro and in a human rheumatoid arthritis/SCID mouse chimera model.  

LENUS (Irish Health Repository)

Serum amyloid A (A-SAA), an acute-phase protein with cytokine-like properties, is expressed at sites of inflammation. This study investigated the effects of A-SAA on chemokine-regulated migration and angiogenesis using rheumatoid arthritis (RA) cells and whole-tissue explants in vitro, ex vivo, and in vivo. A-SAA levels were measured by real-time PCR and ELISA. IL-8 and MCP-1 expression was examined in RA synovial fibroblasts, human microvascular endothelial cells, and RA synovial explants by ELISA. Neutrophil transendothelial cell migration, cell adhesion, invasion, and migration were examined using transwell leukocyte\\/monocyte migration assays, invasion assays, and adhesion assays with or without anti-MCP-1\\/anti-IL-8. NF-kappaB was examined using a specific inhibitor and Western blotting. An RA synovial\\/SCID mouse chimera model was used to examine the effects of A-SAA on cell migration, proliferation, and angiogenesis in vivo. High expression of A-SAA was demonstrated in RA patients (p < 0.05). A-SAA induced chemokine expression in a time- and dose-dependent manner (p < 0.05). Blockade with anti-scavenger receptor class B member 1 and lipoxin A4 (A-SAA receptors) significantly reduced chemokine expression in RA synovial tissue explants (p < 0.05). A-SAA induced cell invasion, neutrophil-transendothelial cell migration, monocyte migration, and adhesion (all p < 0.05), effects that were blocked by anti-IL-8 or anti-MCP-1. A-SAA-induced chemokine expression was mediated through NF-kappaB in RA explants (p < 0.05). Finally, in the RA synovial\\/SCID mouse chimera model, we demonstrated for the first time in vivo that A-SAA directly induces monocyte migration from the murine circulation into RA synovial grafts, synovial cell proliferation, and angiogenesis (p < 0.05). A-SAA promotes cell migrational mechanisms and angiogenesis critical to RA pathogenesis.

Connolly, Mary

2010-06-01

389

SorLA CR-Domains Protect the Amyloid Precursor Protein against Processing  

DEFF Research Database (Denmark)

SorLA is a neuronal sorting receptor that is genetically associated with Alzheimer's disease. SorLA interacts directly with the amyloid precursor protein (APP) and affects the processing of the precursor, leading to a decreased generation of the amyloid-? (A?) peptide. The sorLA complement-type repeat (CR)-domains associate in vitro with APP, but the precise molecular determinants of sorLA-APP complex formation and the mechanisms responsible for the effect of binding on APP processing have not yet been elucidated. Here, we have generated protein expression constructs for sorLA devoid of the 11 CR-domains and for two sorLA mutants harboring substitutions of the fingerprint residues in the central CR-domains. We generated SH-SY5Y cell lines that stably express these sorLA variants to study the binding and processing of APP using co-immunoprecipitation and western blotting/ELISA assays, respectively. We found that the sorLA CR-cluster is essential for interaction with APP and that deletion of the CR-cluster abolishes the protection against APP processing. Mutation of identified fingerprint residues in the sorLA CR-domains leads to changes in the O-linked glycosylation of APP when expressed in SH-SY5Y cells. Our results provide novel information on the mechanisms behind the influence of sorLA activity on APP metabolism by controlling post-translational glycosylation in the Golgi, suggesting new strategies against amyloidogenesis in Alzheimer's disease.

Mehmedbasic, Arnela; Christensen, Sofie K

2014-01-01

390

Palmitoylation of amyloid precursor protein regulates amyloidogenic processing in lipid rafts.  

Science.gov (United States)

Brains of patients affected by Alzheimer's disease (AD) contain large deposits of aggregated amyloid ?-protein (A?). Only a small fraction of the amyloid precursor protein (APP) gives rise to A?. Here, we report that ?10% of APP undergoes a post-translational lipid modification called palmitoylation. We identified the palmitoylation sites in APP at Cys¹?? and Cys¹??. Surprisingly, point mutations introduced into these cysteines caused nearly complete ER retention of APP. Thus, either APP palmitoylation or disulfide bridges involving these Cys residues appear to be required for ER exit of APP. In later compartments, palmitoylated APP (palAPP) was specifically enriched in lipid rafts. In vitro BACE1 cleavage assays using cell or mouse brain lipid rafts showed that APP palmitoylation enhanced BACE1-mediated processing of APP. Interestingly, we detected an age-dependent increase in endogenous mouse brain palAPP levels. Overexpression of selected DHHC palmitoyl acyltransferases increased palmitoylation of APP and doubled A? production, while two palmitoylation inhibitors reduced palAPP levels and APP processing. We have found previously that acyl-coenzyme A:cholesterol acyltransferase (ACAT) inhibition led to impaired APP processing. Here we demonstrate that pharmacological inhibition or genetic inactivation of ACAT decrease lipid raft palAPP levels by up to 76%, likely resulting in impaired APP processing. Together, our results indicate that APP palmitoylation enhances amyloidogenic processing by targeting APP to lipid rafts and enhancing its BACE1-mediated cleavage. Thus, inhibition of palAPP formation by ACAT or specific palmitoylation inhibitors would appear to be a valid strategy for prevention and/or treatment of AD. PMID:23825420

Bhattacharyya, Raja; Barren, Cory; Kovacs, Dora M

2013-07-01

391

The E1 copper binding domain of full-length amyloid precursor protein mitigates copper-induced growth inhibition in brain metastatic prostate cancer DU145 cells.  

Science.gov (United States)

Copper plays an important role in the aetiology and growth of tumours and levels of the metal are increased in the serum and tumour tissue of patients affected by a range of cancers including prostate cancer (PCa). The molecular mechanisms that enable cancer cells to proliferate in the presence of elevated copper levels are, therefore, of key importance in our understanding of tumour growth progression. In the current study, we have examined the role played by the amyloid precursor protein (APP) in mitigating copper-induced growth inhibition of the PCa cell line, DU145. A range of APP molecular constructs were stably over-expressed in DU145 cells and their effects on cell proliferation in the presence of copper were monitored. Our results show that endogenous APP expression was induced by sub-toxic copper concentrations in DU145 cells and over-expression of the wild-type protein was able to mitigate copper-induced growth inhibition via a mechanism involving the cytosolic and E1 copper binding domains of the full-length protein. APP likely represents one of a range of copper binding proteins that PCa cells employ in order to ensure efficient proliferation despite elevated concentrations of the metal within the tumour microenvironment. Targeting the expression of such proteins may contribute to therapeutic strategies for the treatment of cancers. PMID:25305487

Gough, Mallory; Blanthorn-Hazell, Sophee; Delury, Craig; Parkin, Edward

2014-10-31

392

Interaction of thorium with blood serum proteins in vivo  

International Nuclear Information System (INIS)

The distribution of thorium in the blood serum of rats was studied in vivo, using carrier-free 234Th and 59Fe-citrate solution. The chromatographic data presented in this short communication indicate that, as with plutonium, the iron-transport protein, transferrin, is the main carrier protein for thorium. Also, like plutonium, thorium could be displaced from the transferrin complex by excess iron. Further investigations are required to determine if plutonium and thorium are bound to the same sites on the transferrin molecule as iron and whether the binding mechanisms are similar. (U.K.)

393

Plasticity of amyloid fibrils†  

OpenAIRE

In experiments designed to characterize the basis of amyloid fibril stability through mutational analysis of the A?(1-40) molecule, fibrils exhibit consistent, significant structural malleability. In these results, and in other properties, amyloid fibrils appear to more resemble plastic materials generated from synthetic polymers than they do globular proteins. Thus, like synthetic polymers and plastics, amyloid fibrils exhibit both polymorphism, the ability of one polypeptide to form aggreg...

Wetzel, Ronald; Shivaprasad, Shankaramma; Williams, Angela D.

2007-01-01

394

Tau/Amyloid Beta 42 Peptide Test (Alzheimer Biomarkers)  

Science.gov (United States)

... Formal name: Tau Protein and Amyloid Beta 42 Peptide Related tests: Phosporylated Tau (P-tau), APOE Genotyping , ... cerebrospinal fluid (CSF) . Amyloid beta 42 is a peptide (protein fragment). Increased production of amyloid beta 42 ...

395

Sorting by the cytoplasmic domain of the amyloid precursor protein binding receptor SorLA.  

DEFF Research Database (Denmark)

SorLA/LR11 (250 kDa) is the largest and most composite member of the Vps10p-domain receptors, a family of type 1 proteins preferentially expressed in neuronal tissue. SorLA binds several ligands, including neurotensin, platelet-derived growth factor-bb, and lipoprotein lipase, and via complex-formation with the amyloid precursor protein it downregulates generation of Alzheimer's disease-associated Abeta-peptide. The receptor is mainly located in vesicles, suggesting a function in protein sorting and transport. Here we examined SorLA's trafficking using full-length and chimeric receptors and find that its cytoplasmic tail mediates efficient Golgi body-endosome transport, as well as AP-2 complex-dependent endocytosis. Functional sorting sites were mapped to an acidic cluster-dileucine-like motif and to a GGA binding site in the C terminus. Experiments in permanently or transiently AP-1 mu1-chain-deficient cells established that the AP-1 adaptor complex is essential to SorLA's transport between Golgi membranes and endosomes. Our results further implicate the GGA proteins in SorLA trafficking and provide evidence that SNX1 and Vps35, as parts of the retromer complex or possibly in a separate context, are engaged in retraction of the receptor from endosomes. Udgivelsesdato: 2007-Oct

Nielsen, Morten S; Gustafsen, Camilla

2007-01-01

396

Engulfment adapter PTB domain containing 1 interacts with and affects processing of the amyloid-? precursor protein.  

Science.gov (United States)

Previous studies identified engulfment adapter phosphotyrosine binding (PTB) domain containing 1 (GULP1) as an NPXY-motif interactor of low-density lipoprotein receptor-related protein 1 (LRP1) and suggested a potential relevance in Alzheimer's disease (AD). Since AD associated proteins amyloid-? A4 precursor protein (APP) and LRP1 were shown to interact with the PTB domain of Fe65 and several other adapters via their intracellular NPXY-motifs, we examined a possible interaction of GULP1 PTB domain with the YENPTY-motif of APP. Here we demonstrate that GULP1 is present in human hippocampal and neocortical neurons. Confocal live cell imaging revealed that coexpressed and endogenous GULP1 colocalizes with APP in the Golgi and endoplasmic reticulum. Analysis of the interacting domains by co-immunoprecipitation of point and deletion mutants revealed that the interaction depends on the PTB domain of GULP1 and the YENPTY-motif of APP. Coexpression of GULP1 affected APP cell surface localization and suppressed generation of A?40/42 and sAPP?. Taken together, these data identify GULP1 as a novel neuronal APP interacting protein that alters trafficking and processing of APP. PMID:20674096

Beyer, Anja-Silke; von Einem, Bjoern; Schwanzar, Daniel; Keller, Ilona E; Hellrung, Anke; Thal, Dietmar R; Ingelsson, Martin; Makarova, Alexandra; Deng, Meihua; Chhabra, Ekta S; Pröpper, Christian; Böckers, Tobias M; Hyman, Bradley T; von Arnim, Christine A F

2012-04-01

397

Dexras1 interacts with FE65 to regulate FE65-amyloid precursor protein-dependent transcription.  

Science.gov (United States)

FE65 is an adaptor protein that binds to and forms a transcriptionally active complex with the gamma-secretase-derived amyloid precursor protein (APP) intracellular domain. The regulatory mechanisms of FE65-APP-mediated transcription are still not clear. In this report, we demonstrate that Dexras1, a Ras family small G protein, binds to FE65 PTB2 domain and potently suppresses the FE65-APP-mediated transcription. The suppression is not via competition for binding of FE65 between Dexras1 and APP because the two proteins can simultaneously bind to the FE65 PTB2 domain. Phosphorylation of FE65 tyrosine 547 within the PTB2 domain has been shown to enhance FE65-APP-mediated transcription but not to influence binding to APP. Here we find that this phosphorylation event reduces the binding between Dexras1 and FE65. We also demonstrate that Dexras1 inhibits the FE65-APP-mediated transcription of glycogen synthase kinase 3beta (GSK3 beta). Moreover, small interfering RNA knockdown of Dexras1 enhances GSK3 beta expression and increases phosphorylation of Tau, a GSK3 beta substrate. Thus, Dexras1 functions as a suppressor of FE65-APP-mediated transcription, and FE65 tyrosine 547 phosphorylation enhances FE65-APP-mediated transcription, at least in part, by modulating the interaction between FE65 and Dexras1. These findings reveal a novel regulatory mechanism for FE65-APP-mediated signaling. PMID:18922798

Lau, Kwok-Fai; Chan, Wing-Man; Perkinton, Michael S; Tudor, Elizabeth L; Chang, Raymond C C; Chan, H-Y Edwin; McLoughlin, Declan M; Miller, Christopher C J

2008-12-12

398

MD-simulations of Beta-Amyloid Protein Insertion Efficiency and Kinetics into Neuronal Membrane Mimics  

Science.gov (United States)

Early interaction events of beta-amyloid (A?) peptides with the neuronal membranes play a key role in the pathogenesis of Alzheimer's disease. We have used all-atom MD simulations to study the protein insertion efficiency and kinetics of monomeric A?40 and A?42 into phosphatidylcholine lipid bilayers (PC) with and without 40 mole% cholesterol (CHOL) that mimic the cholesterol-enriched and depleted lipid nanodomains of the neuronal plasma membranes. Independent replicates of 200-ns simulations of each protein pre-inserted in the upper lipid layer were generated. In PC bilayers, only 25% of A?40 and 50% of A?42 in the replicates showed complete insertion into the lower lipid layer, whereas the percentages increased to 50% and 100%, respectively, in PC/CHOL bilayers, providing evidence that cholesterol improves the protein insertion efficiency into the bilayers. The rate of protein insertion was proportional to the hydrophobic, transmembrane helix length of the inserted peptide and depended on the cholesterol content. We propose that the lysine snorkeling and C-terminus anchoring of A? to the PC headgroups at the upper and lower lipid/water interfaces represent the dual-transmembrane stabilization mechanisms of A? in the neuronal membrane domains.

Qiu, Liming; Buie, Creighton; Vaughn, Mark; Cheng, Kwan

2011-03-01

399

Binding of an oxindole alkaloid from Uncaria tomentosa to amyloid protein (Abeta1-40).  

Science.gov (United States)

The primary aim of this work was to determine the interactions of an oxindole alkaloid (mitraphylline) isolated from Uncaria tomentosa with beta-amyloid 1-40 (Abeta1-40 protein) applying the capillary electrophoresis (CE) method. Specifically the Hummel-Dreyer method and Scatchard analysis were performed to study the binding of oxindole alkaloids with Abeta1-40 protein. Prior to these studies extraction of the alkaloid of interest was carried out. Identification of the isolated alkaloid was performed by the use of thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) combined with electrospray ionization mass spectrometry (ESI-MS). The proposed approach was proved to be an efficient and accurate method for specific compound isolation and identification purposes. Moreover, analytical information from the CE approach can be considered as the valuable tool for binding constant determination. The binding constant of mitraphylline with Abeta1-40 protein determined by the Hummel-Dreyer method and Scatchard analysis equals K = 9.95 x 10(5) M(-1). The results obtained showed the significant binding of the tested compound with Abeta1-40 protein. These results are discussed and interpreted in the view of developing a strategy for identification of novel compounds of great importance in Alzheimer disease therapy. PMID:17294693

Frackowiak, Teresa; Baczek, Tomasz; Roman, Kaliszana; Zbikowska, Beata; Gle?sk, Micha?; Fecka, Izabela; Cisowski, Wojciech

2006-01-01

400

Interactions of apomorphine with serum and tissue proteins  

International Nuclear Information System (INIS)

Physical and covalent interactions of apomorphine with serum and tissue proteins could influence the drug's disposition and pharmacological activities in mammals. Ultrafiltration, equilibrium dialysis, and ultraviolet spectrophotometric methods have been used to study the reversible binding of apomorphine to bovine, human, rat, and swine plasma proteins. The degree of binding was generally greater than 90%, but variations were noted in some instances on the basis of drug concentrations and pH over the range of 6.8-7.8. Incubation of [8,9-3H2]apomorphine with bovine serum albumin led to retention of radioactivity and a stoichiometrically controlled released of tritium which arose from the reaction of an electrophilic drug oxidation product and protein, producing drug-protein conjugates. In vitro experiments with mouse striatal brain preparations indicated parallel covalent binding reactions. In vivo experiments in mice indicated accumulation of radioactivity in brain regions and other tissues following daily injections of [8,9-3H2]apomorphine for 14 days. The physical and covalent interactions of apomorphine with mammalian tissue proteins could be the cause of longer disposition half-lives in mammals than those previously reported. The covalent interactions, in particular, may be important in elucidating the mechanism of apomorphine-induced behavioral effects in mice

401

Unraveling the mysteries of serum albumin-more than just a serum protein.  

Science.gov (United States)

Serum albumin is a multi-functional protein that is able to bind and transport numerous endogenous and exogenous compounds. The development of albumin drug carriers is gaining increasing importance in the targeted delivery of cancer therapy, particularly as a result of the market approval of the paclitaxel-loaded albumin nanoparticle, Abraxane®. Considering this, there is renewed interest in isolating and characterizing albumin-binding proteins or receptors on the plasma membrane that are responsible for albumin uptake. Initially, the cellular uptake and intracellular localization of albumin was unknown due to the large confinement of the protein within the vascular and interstitial compartment of the body. Studies have since assessed the intracellular localization of albumin in order to understand the mechanisms and pathways responsible for its uptake, distribution and catabolism in multiple tissues, and this is reviewed herein. PMID:25161624

Merlot, Angelica M; Kalinowski, Danuta S; Richardson, Des R

2014-01-01

402

Unraveling the mysteries of serum albumin—more than just a serum protein  

Science.gov (United States)

Serum albumin is a multi-functional protein that is able to bind and transport numerous endogenous and exogenous compounds. The development of albumin drug carriers is gaining increasing importance in the targeted delivery of cancer therapy, particularly as a result of the market approval of the paclitaxel-loaded albumin nanoparticle, Abraxane®. Considering this, there is renewed interest in isolating and characterizing albumin-binding proteins or receptors on the plasma membrane that are responsible for albumin uptake. Initially, the cellular uptake and intracellular localization of albumin was unknown due to the large confinement of the protein within the vascular and interstitial compartment of the body. Studies have since assessed the intracellular localization of albumin in order to understand the mechanisms and pathways responsible for its uptake, distribution and catabolism in multiple tissues, and this is reviewed herein. PMID:25161624

Merlot, Angelica M.; Kalinowski, Danuta S.; Richardson, Des R.

2014-01-01

403

Unraveling the mysteries of serum albumin – more than just a serum protein.  

Directory of Open Access Journals (Sweden)

Full Text Available Serum albumin is a multi-functional protein that is able to bind and transport numerous endogenous and exogenous compounds. The development of albumin drug carriers is gaining increasing importance in the targeted delivery of cancer therapy, particularly as a result of the market approval of the paclitaxel-loaded albumin nanoparticle, Abraxane®. Considering this, there is renewed interest in isolating and characterizing albumin-binding proteins or receptors on the plasma membrane that are responsible for albumin uptake. Initially, the cellular uptake and intracellular localization of albumin was unknown due to the large confinement of the protein within the vascular and interstitial compartment of the body. Studies have since assessed the intracellular localization of albumin in order to understand the mechanisms and pathways responsible for its uptake, distribution and catabolism in multiple tissues, and this is reviewed herein.

AngelicaM.Merlot

2014-08-01

404

Functional Amyloids Signal Their Arrival  

Science.gov (United States)

Amyloids have traditionally been associated with misfolded protein aggregates and debilitating neurodegenerative diseases. However, a growing number of functional amyloids have now been described that demonstrate that amyloid formation can be an integral part of normal cellular physiology. Functional amyloid production is highly regulated, and the resulting fibers serve a variety of roles for the cells that produce them. A new role for amyloid as storage reservoirs for peptide hormones within mammalian secretory granules has been discovered. More than 30 different peptide hormones have been found to form amyloids in vitro, and both rats and mice have been shown to store hormone amyloid deposits in secretory granules. Thus, the emerging evidence adds to the diverse roles of amyloid and raises intriguing questions for both the peptide hormone and the functional amyloid fields.

Matthew P. Badtke (Ann Arbor; University of Michigan REV)

2009-07-21

405

Dynamic behavior of small heat shock protein inhibition on amyloid fibrillization of a small peptide (SSTSAA) from RNase A  

International Nuclear Information System (INIS)

Highlights: ? Mechanism of small heat shock protein inhibition on fibril formation was studied. ? Peptide SSTSAA with modified ends was used for amyloid fibril formation. ? FRET signal was followed during the fibril formation. ? Mj HSP16.5 inhibits fibril formation when introduced in the lag phase. ? Mj HSP16.5 slows down fibril formation when introduced after the lag phase. -- Abstract: Small heat shock proteins, a class of molecular chaperones, are reported to inhibit amyloid fibril formation in vitro, while the mechanism of inhibition remains unknown. In the present study, we investigated the mechanism by which Mj HSP16.5 inhibits amyloid fibril formation of a small peptide (SSTSAA) from RNase A. A model peptide (dansyl-SSTSAA-W) was designed by introducing a pair of fluorescence resonance energy transfer (FRET) probes into the peptide, allowing for the monitoring of fibril formation by this experimental model. Mj HSP16.5 completely inhibited fibril formation of the model peptide at a molar ratio of 1:120. The dynamic process of fibril formation, revealed by FRET, circular dichroism, and electron microscopy, showed a lag phase of about 2 h followed by a fast growth period. The effect of Mj HSP16.5 on amyloid fibril formation was investigated by adding it into the incubation solution during different growth phases. Adding Mj HSP16.5 to the incubating peptide before or during the lag phase completely inhibited fibril formation. However, introducing Mj HSP16.5 after the lag phase only slowed down the fibril formation process by adhering to the already formed fibrils. These findings provide insight into the inhibitory roles of small heat shock proteins on amyloid fibril formation at the molecular level.

406

Minocycline alleviates beta-amyloid protein and tau pathology via restraining neuroinflammation induced by diabetic metabolic disorder  

Directory of Open Access Journals (Sweden)

Full Text Available Zhiyou Cai,1 Yong Yan,2 Yonglong Wang2 1Department of Neurology, the Lu’an Affiliated Hospital of Anhui Medical University, Lu’an People’s Hospital, Lu’an, Anhui Province, People’s Republic of China; 2Department of Neurology, the First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, People’s Republic of China Background: Compelling evidence has shown that diabetic metabolic disorder plays a critical role in the pathogenesis of Alzheimer’s disease, including increased expression of ?-amyloid protein (A? and tau protein. Evidence has supported that minocycline, a tetracycline derivative, protects against neuroinflammation induced by neurodegenerative disorders or cerebral ischemia. This study has evaluated minocycline influence on expression of A? protein, tau phosphorylation, and inflammatory cytokines (interleukin-1? and tumor necrosis factor-? in the brain of diabetic rats to clarify neuroprotection by minocycline under diabetic metabolic disorder. Method: An animal model of diabetes was established by high fat diet and intraperitoneal injection of streptozocin. In this study, we investigated the effect of minocycline on expression of A? protein, tau phosphorylation, and inflammatory cytokines (interleukin-1? and tumor necrosis factor-? in the hippocampus of diabetic rats via immunohistochemistry, western blotting, and enzyme-linked immunosorbent assay. Results: These results showed that minocycline decreased expression of A? protein and lowered the phosphorylation of tau protein, and retarded the proinflammatory cytokines, but not amyloid precursor protein. Conclusion: On the basis of the finding that minocycline had no influence on amyloid precursor protein and beta-site amyloid precursor protein cleaving enzyme 1 which determines the speed of A? generation, the decreases in A? production and tau hyperphosphorylation by minocycline are through inhibiting neuroinflammation, which contributes to A? production and tau hyperphosphorylation. Minocycline may also lower the self-perpetuating cycle between neuroinflammation and the pathogenesis of tau and A? to act as a neuroprotector. Therefore, the ability of minocycline to modulate inflammatory reactions may be of great importance in the selection of neuroprotective agents, especially in chronic conditions like diabetes and Alzheimer’s disease. Keywords: diabetes mellitus, minocycline, tau protein, ?-amyloid protein

Cai Z

2013-08-01

407

ATBF1 is a novel amyloid-? protein precursor (A?PP) binding protein that affects A?PP expression.  

Science.gov (United States)

The cytoplasmic C-terminal domain of amyloid-? protein precursor (A?PP) binds to several proteins that regulate the trafficking and processing of A?PP and affects amyloid-? (A?) production. We previously reported that levels of AT-motif binding factor 1 (ATBF1) are increased in the brains of 17-month-old Tg2576 mice compared with wild-type controls, and that A?42 increases ATBF1 expression, inducing death in primary rat cortical neurons. Here, we show that ATBF1 levels are increased in the cytoplasm of hippocampal neurons in Alzheimer's disease (AD) brains compared with non-AD brains. Furthermore, cotransfection of human embryonic kidney (HEK293T) and human neuroblastoma (SH-SY5Y) cells with ATBF1 and A?PP695 increased steady-state levels of A?PP via the binding of ATBF1 to the A?PP cytoplasmic domain (amino acids 666-690), resulting in increased A? production and cellular and soluble A?PP (sA?PP) levels without affecting the activity or levels of A?PP processing enzymes (?-, ?-, or ?-secretase). Conversely, knockdown of endogenous ATBF1 reduced levels of cellular A?PP, sA?PP, and A? in HEK293 cells overexpressing human A?PP695. Our findings provide insight into the dynamics of A?PP processing and A? production, and suggest that ATBF1 is a novel A?PP binding protein that may be a suitable therapeutic target for AD. PMID:25079792

Uhm, Kyung-Ok; Kim, Mi-Jeong; Kawaguchi, Makoto; Akatsu, Hiroyasu; Miura, Yutaka; Misumi, Sachiyo; Hida, Hideki; Choi, Eun-Kyoung; Kim, Yong-Sun; Michikawa, Makoto; Jung, Cha-Gyun

2015-01-01