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Serum Amyloid P Component (SAP)-Like Protein From Botryllid Ascidians Provides a Clue to Amyloid Function  

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The HA-1 lectin isolated from Botrylloides leachii has an amino acid composition similar to that of mammalian serum amyloid protein (SAP). SAP is a universal component of mammalian amyloid deposits. Like SAP, HA-1 has a disc ultrastructure, and antibody to HA-1 binds both (a) to amyloidlike fibers deposited between rejected Botrylloides colonies and (b) to cerebral amyloid deposits in Alzheimer's disease brains. Deposition of protochordate amyloid within rejection sites and sur...

Scofield, V. L.; Puntambekar, L.; Schluter, S. F.; Coombe, D. R.

1992-01-01

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

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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

1979-01-01

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Identification of Human Serum Proteins Which Interact With Alzheimer`s Amyloid ?A4 Protein  

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Full Text Available Alzheimer`s amyloid ?A4 protein fused with glutathione S-transferase (GST was highly expressed using a strong prokaryotic expression system in Escherichia coli. The expressed protein had expected molecular mass on SDS-PAGE and appeared exclusively immunoreactive with antibody specific for ?A4 epitope. This recombinant protein was purified with a combination of urea solubilization and ion exchange chromatography. To identify the human serum proteins which interact with ?A4, affinity columns were prepared by immobilizing GST- ?A4 and GST respectively. Using the affinity columns and human serum, we have observed an interaction of ?A4 with serum proteins. Two proteins of Mr 45 and 15 kDa were identified on SDS-PAGE to be involved in the interaction. Our demonstration of the ability of ?A4 to interact with serum protein strongly support the notion that such an interaction may underlie with the biological function of ?A4 in vivo.

Golam Sadik

2000-01-01

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Comparison of C-Reactive Protein and Serum Amyloid A Protein in Septic Shock Patients  

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Full Text Available Septic shock is a severe inflammatory state caused by an infectious agent. Our purpose was to investigate serum amyloid A (SAA protein and C-reactive protein (CRP as inflammatory markers of septic shock patients. Here we evaluate 29 patients in postoperative period, with septic shock, in a prospective study developed in a surgical intensive care unit. All eligible patients were monitored over a 7-day period by sequential organ failure assessment (SOFA score, daily CRP, SAA, and lactate measurements. CRP and SAA strongly correlated up to the fifth day of observation but were not good predictors of mortality in septic shock.

Fábio Ely Martins Benseñor

2008-03-01

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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)  

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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

1986-01-01

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

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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 (AgNO_3), 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 AgNO_3. It was (unexpectedly) observed that brief pretreatment (12 h) with colchicine augmented the acute phase SAA response to AgNO_3 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

1986-01-01

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Serum amyloid A protein (SAA) from mink, horse, and man: a comparative study  

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Serum amyloid A protein (SAA) was isolated from mink, horse, and human serum by ultracentrifugation and gel filtration and characterized by two-dimensional gel electrophoresis, Western blotting followed by autoradiography and N-terminal amino acid analysis. SAA was found in similar quantities in the high density lipoprotein (HDL) fraction of serum from a patient suffering from systemic juvenile rheumatoid arthritis (JRA) and mink stimulated with lipopolysaccharide (LPS), and in somewhat smaller quantities in serum from horses stimulated with Escherichia coli cultures. Only very small quantities were present in normal human controls and not detectable in normal mink and horse. Striking similarities were found between human and mink SAA with respect to molecular weight, isolectric point and degree of heterogeneity, while the molecular weight, isolectric point and degree of heterogeneity, while the molecular weight of horse SAA seemed to be somewhat lower, and no obvious heterogeneity could be demonstrated in this protein using two-dimensional gel electrophoresis. Immunologic cross-reactivity between SAA from the three species was not found. In contrast to human and horse HDL, mink HDL was found not to contain apoA-II and only minute amounts of apoC proteins. Normal horse HDL also contained additional apoproteins not present in HDL from the other species. N-terminal amino acids analysis of SAA from mink and horse demonstrated the same similarity with the corresponding AA protein as previously reported for human SAA/AA

1986-01-01

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Two major ruminant acute phase proteins, haptoglobin and serum amyloid A, as serum biomarkers during active sheep scab infestation.  

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Two ruminant acute phase proteins (APPs), haptoglobin (Hp) and serum amyloid A (SAA), were evaluated as serum biomarkers (BMs) for sheep scab-a highly contagious ectoparasitic disease caused by the mite Psoroptes ovis, which is a major welfare and production threat worldwide. The levels of both APPs increased in serum following experimental infestation of sheep with P. ovis, becoming statistically significantly elevated from pre-infestation levels at 4 weeks post-infestation. Following successful treatment of infested sheep with an endectocide, Hp and SAA serum levels declined rapidly, with half lives of less than 3 days. In contrast, serum IgG levels which specifically bound the P. ovis-derived diagnostic antigen Pso o 2 had a half-life of 56 days. Taking into account pre-infestation serum levels, rapidity of response to infestation and test sensitivity at the estimated optimum cut-off values, SAA was the more discriminatory marker. These studies illustrated the potential of SAA and Hp to indicate current sheep scab infestation status and to augment the existing Pso o 2 serological assay to give disease-specific indications of both infestation and successful treatment. PMID:24176040

Wells, Beth; Innocent, Giles T; Eckersall, Peter D; McCulloch, Eilidh; Nisbet, Alasdair J; Burgess, Stewart T G

2013-01-01

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

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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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Isolation and characterization of pharmaceutical grade human pentraxins, serum amyloid P component and C-reactive protein, for clinical use.  

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The human pentraxin proteins, serum amyloid P component (SAP) and C-reactive protein (CRP) are important in routine clinical diagnosis, SAP for systemic amyloidosis and CRP for monitoring the non-specific acute phase response. They are also targets for novel therapies currently in development but their roles in health and disease are controversial. Thus, both for clinical use and to rigorously elucidate their functions, structurally and functionally intact, pharmaceutical grade preparations o...

Pepys, M. B.; Gallimore, J. R.; Lloyd, J.; Li, Z.; Graham, D.; Taylor, G. W.; Ellmerich, S.; Mangione, P. P.; Tennent, G. A.; Hutchinson, W. L.; Millar, D. J.; Bennett, G.; More, J.; Evans, D.; Mistry, Y.

2012-01-01

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Serum Albumin Prevents Protein Aggregation and Amyloid Formation and Retains Chaperone-like Activity in the Presence of Physiological Ligands  

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Although serum albumin has an established function as a transport protein, evidence is emerging that serum albumin may also have a role as a molecular chaperone. Using established techniques to characterize chaperone interactions, this study demonstrates that bovine serum albumin: 1) preferentially binds stressed over unstressed client proteins; 2) forms stable, soluble, high molecular weight complexes with stressed client proteins; 3) reduces the aggregation of client proteins when it is present at physiological levels; and 4) inhibits amyloid formation by both WT and L55P transthyretin. Although the antiaggregatory effect of serum albumin is maintained in the presence of physiological levels of Ca2+ and Cu2+, the presence of free fatty acids significantly alters this activity: stabilizing serum albumin at normal levels but diminishing chaperone-like activity at high concentrations. Moreover, here it is shown that depletion of albumin from human plasma leads to a significant increase in aggregation under physiologically relevant heat and shear stresses. This study demonstrates that serum albumin possesses chaperone-like properties and that this activity is maintained under a number of physiologically relevant conditions.

Finn, Thomas E.; Nunez, Andrea C.; Sunde, Margaret; Easterbrook-Smith, Simon B.

2012-01-01

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Serum amyloid A protein, apolipoprotein A-I, and apolipoprotein B during the course of acute myocardial infarction.  

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Serum amyloid A protein (SAA), apolipoprotein A-I (apoA-I), apolipoprotein B (apoB) concentrations, and creatine kinase (CK)-MB isoenzyme activity were serially measured in 10 patients during the course of acute myocardial infarction. Pronounced increases in SAA concentrations were observed in all patients during infarction. The highest SAA values were observed, on average, 67 hours after the onset of chest pain. After infarction both apoA-I and apoB concentrations decreased. The reduction in...

Maury, C. P.; To?tterman, K. J.; Gref, C. G.; Ehnholm, C.

1988-01-01

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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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Evaluation of Sialic Acid and Acute Phase Proteins (Haptoglobin and Serum Amyloid A in Clinical and Subclinical Bovine Mastitis  

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Full Text Available The present study was conducted to evaluate the concentrations of sialic acids (total, lipid bound and protein bound and their correlation with acute phase proteins (haptoglobin and serum amyloid A in clinical and subclinical mastitis of cattle. Thirty subclinical mastitic cows with positive California mastitis test (CMT test and no clinical signs of mastitis, 10 clinical mastitic cows and 10 healthy cows with negative CMT test and normal somatic cell count were selected. Milk and blood samples were collected after confirmation of clinical and subclinical mastitis by somatic cell count and bacterial identification. Serum haptoglobin (Hp, serum amyloid A (SAA, total sialic acid (TSA, lipid bound sialic acid (LBSA and protein bound sialic acid (PBSA were measured by validated standard methods. Haptoglobin and SAA increased significantly in both types of mastitis compared with control group (P<0.001. However, the ratio of HP/SAA was significantly different from the control group only in clinical mastitis. The results showed that TSA and LBSA were significantly different in control group compared with clinical and subclinical mastitis (P<0.001. Protein bound sialic acid did not change in subclinical mastitis in comparison with control group (P=0.86. There was positive correlation between LBSA and PBSA in clinical mastitis (r=0.72, P=0.02 whereas significant negative correlation was observed between LBSA and PBSA in subclinical mastitis (r=-0.62, P<0.001. Results also showed no correlation between Hp and SAA with each other or with any other parameters in study groups.

S. Nazifi*, M. Haghkhah1, Z. Asadi, M. Ansari-Lari2, M. R. Tabandeh3, Z. Esmailnezhad and M. Aghamiri

2011-01-01

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Nanophotonics of protein amyloids  

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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  

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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 B; Langhorn, Rebecca

2014-01-01

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The diagnostic role of human epididymis protein 4 and serum amyloid-A in early-stage endometrial cancer patients.  

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The aim of this study was to evaluate the prognostic and predictive efficacy of the human epididymis secretory protein 4 (HE4) and serum amyloid-A (S-AA) together with the other tumor markers (CA 125, CA 15-3, CEA, and CA 19-9) in endometrial cancer patients. The study group consisted of 64 patients with defined stage and grade of endometrial cancer and 60 women with benign uterine diseases. Thirty-four healthy women were defined as the control group. Fasting blood samples were collected prior to surgery and tumor marker levels were determined in blood samples by E170 autoanalyzer. S-AA concentrations were measured by particle-enhanced immunonephelometry. Preoperative serum HE4 and S-AA levels were significantly higher in endometrial cancer patients than in controls, whereas the other measured parameters were not significantly different. Serum levels of HE4 were related to both the stage and grade of tumor. The best cutoff point for HE4 was determined to be 59.7 pmol/L; with 75 % sensitivity and 65.5 % specificity. For S-AA, the cutoff point was 8.8 U/mL, with 68.7 % sensitivity and 58.6 % specificity. The combination of HE4, CA 125, CEA, and S-AA raised the sensitivity to 84 %. Preoperative measurement of serum HE4 and S-AA may be of help in early detection of endometrial cancer. Preoperative screening with these markers may provide important information about the patient's outcome and prognosis. PMID:23640061

Omer, Beyhan; Genc, Sema; Takmaz, Ozguc; Dirican, Ahmet; Kusku-Kiraz, Zeynep; Berkman, Sinan; Gurdol, Figen

2013-10-01

18

Specific localization and imaging of amyloid deposits in vivo using 123I-labeled serum amyloid P component  

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Highly specific, high-resolution scintigraphic images of amyloid-laden organs in mice with experimentally induced amyloid A protein (AA) amyloidosis were obtained after intravenous injection of 123I-labeled serum amyloid P component (SAP). Interestingly, a much higher proportion (up to 40%) of the injected dose of heterologous human SAP localized to amyloid and was retained there than was the case with isologous mouse SAP, indicating that human SAP binds more avidly to mouse AA fibrils than d...

1988-01-01

19

Effects of repeated intra-articular administration of amikacin on serum amyloid A, total protein and nucleated cell count in synovial fluid from healthy horses  

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REASONS FOR PERFORMING STUDY: Serum amyloid A (SAA) in synovial fluid has recently been used as a marker for septic arthritis in horses but the effects of repeated intra-articular (IA) administration of amikacin on synovial SAA concentrations are unknown. OBJECTIVES: To report the effect of repeated IA administration of amikacin on SAA, total protein (TP), nucleated cell count (NCC) and differential NCC in synovial fluid of healthy equine joints. METHODS: A controlled, 2 period crossove...

Sanchez Teran, A. F.; Rubio-martinez, Luis M.; Villarino, N. F.; Sanz, Macarena G.

2012-01-01

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

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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)

1988-06-25

 
 
 
 
21

Serum amyloid A and C-reactive protein positive nodule in alcoholic liver cirrhosis, hard to make definite diagnosis.  

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We describe a case of serum amyloid A (SAA) and C-reactive protein (CRP) positive nodule detected by immunohistochemical analysis in a 37-year-old woman with alcohol-related cirrhosis. Imaging studies at first admission pointed to hepatocellular carcinoma (HCC), a dysplastic nodule, an inflammatory pseudotumor or focal nodular hyperplasia (FNH). Ultrasonography-guided biopsy in Segment 2 showed minimal atypical changes, except for a slight increase in cell density and micronodular cirrhosis in the non-nodular portion. gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging carried out after a year and a half revealed hypervascularity in the arterial phase and isointensity in the hepatobiliary phase. Three years thereafter, however, the imaging displayed a change from isointensity to a defect in the hepatobiliary phase, and the nodule demonstrated minimal histological atypia. Immunohistochemical staining of the nodule was positive for SAA, CRP, liver fatty acid-binding protein and glutamine synthetase, but negative for ?-catenin, heat shock protein 70 and Glypican 3. Organic anion transporter (OATP)8 staining was weaker in the nodule than in the non-nodular portion of the alcohol-related micronodular cirrhosis. The nodule was diagnosed as an SAA and CRP positive nodule, and HCC was ruled out. Despite the change from isointensity to a defect in the hepatobiliary phase, no evidence of HCC was found in the biopsy specimen. The change may be explained more by the weak OATP8 staining compared with that of alcohol-related liver cirrhosis than by malignant transformation into HCC. PMID:23607539

Kim, Soo Ryang; Kondo, Fukuo; Otono, Yumi; Imoto, Susumu; Ando, Kenji; Hirakawa, Makoto; Fukuda, Katsumi; Sasaki, Madoka; Kim, Soo Ki; Komaki, Takamitsu; Tsuchida, Shinobu; Kobayashi, Sawako; Matsuoka, Toshiyuki; Kudo, Masatoshi

2014-05-01

22

The acute-phase protein serum amyloid A induces endothelial dysfunction that is inhibited by high-density lipoprotein.  

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The acute-phase protein serum amyloid A (SAA) is elevated during inflammation and may be deposited in atheroma where it promotes atherosclerosis. We investigated the proatherogenic effects of SAA on the vascular endothelium and their regulation by high-density lipoprotein (HDL). Exposure of human aortic endothelial cells (HAEC) to SAA (0.25-25?g/ml) decreased nitric oxide ((•)NO) synthesis/bioavailability, although the endothelial NO synthase monomer-to-dimer ratio was unaffected. SAA (10?g/ml) stimulated a Ca(2+) influx linked to apocynin-sensitive superoxide radical anion (O(2)(•-)) production. Gene expression for arginase-1, nuclear factor ?B (NF-?B), interleukin-8, and tissue factor (TF) increased within 4h of SAA stimulation. Enzymatically active Arg-1/2 was detected in HAEC cultured with SAA for 24h. Therefore, in addition to modulating (•)NO bioavailability by stimulating O(2)(•-) production in the endothelium, SAA modulated vascular l-Arg bioavailability. SAA also diminished relaxation of preconstricted aortic rings induced by acetylcholine, and added superoxide dismutase restored the vascular response. Preincubation of HAEC with HDL (100 or 200, but not 50, ?g/ml) before (not after) SAA treatment ameliorated the Ca(2+) influx and O(2)(•-) production; decreased TF, NF-?B, and Arg-1 gene expression; and preserved overall vascular function. Thus, SAA may promote endothelial dysfunction by modulating (•)NO and l-Arg bioavailability, and HDL pretreatment may be protective. The relative HDL to SAA concentrations may regulate the proatherogenic properties of SAA on the vascular endothelium. PMID:21784147

Witting, Paul K; Song, Changjie; Hsu, Kenneth; Hua, Susan; Parry, Sarah N; Aran, Roshanak; Geczy, Carolyn; Freedman, Saul Benedict

2011-10-01

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Serum insulin-like growth factor-I, iron, C-reactive protein, and serum amyloid A for prediction of outcome in dogs with pyometra.  

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Pyometra, accumulation of pus in the uterus, is a bacterial infection that frequently initiates systemic inflammation. The disease may have lethal consequences when the systemic effects are severe or complications occur. Markers for identifying high-risk patients and predicting outcome are therefore in high demand. The objective of this study was to measure serum concentrations of insulin-like growth factor-I (IGF-I), iron, C-reactive protein (CRP), and serum amyloid A (SAA) in bitches with pyometra and to explore the possible value of these variables for detection of increased morbidity. In total, 31 bitches were diagnosed with pyometra and destined for surgical treatment (ovariohysterectomy) and 17 healthy bitches were included in the study. Concentrations of IGF-I and iron were lower in the pyometra group (mean concentration 221.2 ± 22.5 ng/mL and 16.9 ± 1.6 ?mol/L, respectively) compared with the healthy control group (mean concentration 366.7 ± 46.2 ng/mL and 38.1 ± 2.7 ?mol/L, respectively). In contrast, concentrations of CRP and SAA were significantly higher in bitches with pyometra (mean concentrations 212.9 ± 17.3 mg/L and 119.9 ± 8.5 mg/L, respectively) compared with the control group (<5 mg/L and <10 mg/L, respectively). None of the explored variables were associated with morbidity as measured by duration of postoperative hospitalization. In conclusion, IGF-I and iron concentrations were decreased in pyometra, whereas SAA and CRP concentrations were increased in the disease. Although unspecific, measurement of these variables may be valuable as adjunctive markers for prognosis in cases of pyometra. PMID:24661434

Jitpean, Supranee; Holst, Bodil Ström; Höglund, Odd V; Pettersson, Ann; Olsson, Ulf; Strage, Emma; Södersten, Fredrik; Hagman, Ragnvi

2014-07-01

24

Serum amyloid a in clinical practice  

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Full Text Available Serum amyloid A (SAA is an acute phase first class protein discovered a quarter of the century ago. Its concentration depends on clinical findings of the patient, illness activity and the therapy applied. SAA increases moderately to markedly (100-1000 mg/l in bacterial and fungal infections, invasive malignant diseases, tissue injuries in the acute myocardial infarction and autoimmune diseases such as rheumatoid arthritis and vasculitis. Mild elevation (10-100 mg/l is often seen in viral infections, systemic lupus erythematosus and localized inflammation or tissue injuries in cystitis and cerebral infarction. SAA as sensitive, non-invasive parameter is used in organ transplantation where early and correct diagnosis is needed as well as where prompt therapy is required. Besides acute kidney allograft rejection, SAA is used in the diagnosis of rejection after liver transplantation, simultaneous pancreas and kidney transplantation and also in bone marrow transplantation (acute „graft vs. host disease". Simultaneous determination of C-reactive protein (CRP and SAA may point to acute kidney allograft rejection. Standard immunosuppressive therapy with cyclosporine A and prednisolone significantly suppresses the acute phase CRP reaction both in operation itself and acute rejection, but not in infection. On the other hand, SAA rejection in operation, acute allograft rejection and infection is present in spite of cyclosporine A and steroids therapy. Different reaction of SAA and CRP in transplant patients to cyclosporine A therapy helps in differentiation between the infection and rejection. Although CRP and SAA are sensitive and acute phase reactants, their serum concentrations cannot be valued as prognostic and diagnostic criteria without creatinine serum concentration and clinical findings. In addition, they offer important information for clinical diagnosis as well as the kind of therapy.

Jovanovi? Dijana B.

2004-01-01

25

Kinetics of human serum amyloid A  

International Nuclear Information System (INIS)

In order to better understand the pathogenetic role of serum amyloid A (SAA) we studied the kinetics of "1"3"1I radiolabelled pure SAA, extracted from 400 ml serum of a human volunteer. 50 microCi of "1"3"1I SAA and 15 microCi "1"2"5I labelled sodium iodide were administered i.v. on two occasions at 6 month intervals. Serum and plasma samples were collected at 10-20 min intervals x 10, then once daily x 10; lymphocytes were separated from monocytes and granulocytes. Counts per minute of "1"3"1I and "1"2"5I were measured in each sample in the serum, in serum precipitates resulting after addition of a rabbit anti-SAA antibody and of TCA and in various cell subpopulations as well as in the whole urine and TCA precipitated urine from each micturition. The "1"3"1I disappearance curves from the plasma and serum precipitates were semilogarithmically plotted; cumulative "1"3"1I cpm in plasma, cells and urine at various intervals were determined. Body scanning was performed at 2, 16, and 48 h. The results of the two experiments were very similar. The curve of "1"3"1I SAA in plasma TCA precipitates indicated the existence of 4 compartments likely due to uptake of "1"3"1I SAA by some plasma proteins, circulating cells and other tissues; later release from tissues started at 6 h. The "1"3"1I SAA half-life time in these compartments was found to be 35, 170, 255, and 550 min, respectively. Tissue binding of "1"3"1I was also suggested by a rising of the "1"2"5I:"1"3"1I ratio with time and by a 26% release of "1"3"1I in the urine at 15 h which could not account for its plasma disappearance. Scanning, except for "1"3"1I uptake in the spleen at 2 h likely due to blood activity, showed no organ concentration. 92% of the injected "1"3"1I was found in the urine but only 6.2% of "1"3"1I SAA was accounted for in urine precicipitates

1986-01-01

26

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 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.)

1998-07-01

27

Serum amyloid P inhibits dermal wound healing  

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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 differentiation of monocytes into fibrocytes. Thus, we hypothesized that the addition of exogenous SAP would hinder the normal wound healing process. Excisional murine dorsal wounds were either inj...

Naik-mathuria, Bindi; Pilling, Darrell; Crawford, Jeff R.; Gay, Andre N.; Smith, C. Wayne; Gomer, Richard H.; Olutoye, Oluyinka O.

2008-01-01

28

Human serum amyloid P component is an invariant constituent of amyloid deposits and has a uniquely homogeneous glycostructure.  

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Human serum amyloid P component (SAP) is a normal plasma protein and the precursor of amyloid P component (AP), a universal constituent of the abnormal tissue deposits in amyloidosis, including Alzheimer disease. We show here that its single N-linked biantennary oligosaccharide does not display the microheterogeneity usually characteristic of glycoproteins. The protein and the glycan structures of AP were also invariant, their resistance to degradation suggesting a role in persistence of amyl...

Pepys, M. B.; Rademacher, T. W.; Amatayakul-chantler, S.; Williams, P.; Noble, G. E.; Hutchinson, W. L.; Hawkins, P. N.; Nelson, S. R.; Gallimore, J. R.; Herbert, J.

1994-01-01

29

Specific localization and imaging of amyloid deposits in vivo using 123I-labeled serum amyloid P component  

International Nuclear Information System (INIS)

Highly specific, high-resolution scintigraphic images of amyloid-laden organs in mice with experimentally induced amyloid A protein (AA) amyloidosis were obtained after intravenous injection of 123I-labeled serum amyloid P component (SAP). Interestingly, a much higher proportion (up to 40%) of the injected dose of heterologous human SAP localized to amyloid and was retained there than was the case with isologous mouse SAP, indicating that human SAP binds more avidly to mouse AA fibrils than does mouse SAP. Specificity of SAP localization was established by the failure of the related proteins, human C-reactive protein and Limulus C-reactive protein, to deposit significantly in amyloid and by the absence of human SAP deposition in nonamyloidotic organs. However, only partial correlations were observed between the quantity of SAP localized and two independent estimates, histology and RIA for AA of the amount of amyloid in particular organs. It is not clear which of the three methods used reflects better the extent or clinical significance of the amyloid deposits but in vivo localization of radiolabeled SAP, detectable and quantifiable by gamma camera imaging, is apparently extremely sensitive. These findings establish the use of labeled SAP as a noninvasive in vivo diagnostic probe in experimental amyloidosis, potentially capable of revealing the natural history of the condition, and suggest that it may also be applicable generally as a specific targeting agent for diagnostic and even therapeutic purposes in clinical amyloidosis

1988-03-01

30

Specific localization and imaging of amyloid deposits in vivo using /sup 123/I-labeled serum amyloid P component  

Energy Technology Data Exchange (ETDEWEB)

Highly specific, high-resolution scintigraphic images of amyloid-laden organs in mice with experimentally induced amyloid A protein (AA) amyloidosis were obtained after intravenous injection of /sup 123/I-labeled serum amyloid P component (SAP). Interestingly, a much higher proportion (up to 40%) of the injected dose of heterologous human SAP localized to amyloid and was retained there than was the case with isologous mouse SAP, indicating that human SAP binds more avidly to mouse AA fibrils than does mouse SAP. Specificity of SAP localization was established by the failure of the related proteins, human C-reactive protein and Limulus C-reactive protein, to deposit significantly in amyloid and by the absence of human SAP deposition in nonamyloidotic organs. However, only partial correlations were observed between the quantity of SAP localized and two independent estimates, histology and RIA for AA of the amount of amyloid in particular organs. It is not clear which of the three methods used reflects better the extent or clinical significance of the amyloid deposits but in vivo localization of radiolabeled SAP, detectable and quantifiable by gamma camera imaging, is apparently extremely sensitive. These findings establish the use of labeled SAP as a noninvasive in vivo diagnostic probe in experimental amyloidosis, potentially capable of revealing the natural history of the condition, and suggest that it may also be applicable generally as a specific targeting agent for diagnostic and even therapeutic purposes in clinical amyloidosis.

Hawkins, P.N.; Myers, M.J.; Epenetos, A.A.; Caspi, D.; Pepys, M.B.

1988-03-01

31

Activation of NF-?B contributes to production of pig-major acute protein and serum amyloid A in pigs experimentally infected with porcine circovirus type 2.  

Science.gov (United States)

Acute phase proteins (APPs) have protective and regulatory roles in the inflammatory response. Previous studies indicate that APPs in serum change after pigs are infected with porcine circovirus type 2 (PCV2), but the mechanisms underlying APP production have remained unclear. In this present study, 35-day-old pigs were challenged with PCV2 and responses compared to an uninfected control group. To investigate the concentrations of APPs in serum and the activity of NF-?B in the liver, five pigs in the PCV2-infected group were euthanized at 14, 21 and 35days post inoculation (dpi) while four pigs were sacrificed in the control group at 0, 14, 21 and 35 days, respectively. The concentrations of pig-major acute protein (Pig-MAP), C-reactive protein (CRP) and serum amyloid A (SAA) in infected animals were increased at 14 and 21 dpi, while the concentration of alpha-1 acid glycoprotein (AGP) was lower at 35 dpi, indicating that PCV2 induced the production of APPs. Moreover, the DNA binding activity of NF-?B and expression levels of NF-?B p65 subunit (NF-?B p65) from the cytoplasm to nucleus were increased at 14 and 21 dpi in the liver of infected pigs, while the phosphorylation of I?B? (p-I?B?) in the liver was also increased at 21dpi. This demonstrated that PCV2 infection induced the activation of NF-?B. Both SAA and Pig-MAP concentrations correlated significantly with expression levels of NF-?B p65, indicating that activation of NF-?B contributes to the production of SAA and Pig-MAP. PMID:24011594

Lv, Yingjun; Zhang, Xiujuan; Sun, Yun; Zhang, Shuxia

2013-12-01

32

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

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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

33

Protection of human podocytes from shiga toxin 2-induced phosphorylation of mitogen-activated protein kinases and apoptosis by human serum amyloid P component.  

Science.gov (United States)

Hemolytic uremic syndrome (HUS) is mainly induced by Shiga toxin 2 (Stx2)-producing Escherichia coli. Proteinuria can occur in the early phase of the disease, and its persistence determines the renal prognosis. Stx2 may injure podocytes and induce proteinuria. Human serum amyloid P component (SAP), a member of the pentraxin family, has been shown to protect against Stx2-induced lethality in mice in vivo, presumably by specific binding to the toxin. We therefore tested the hypothesis that SAP can protect against Stx2-induced injury of human podocytes. To elucidate the mechanisms underlying podocyte injury in HUS-associated proteinuria, we assessed Stx2-induced activation of mitogen-activated protein kinases (MAPKs) and apoptosis in immortalized human podocytes and evaluated the impact of SAP on Stx2-induced damage. Human podocytes express Stx2-binding globotriaosylceramide 3. Stx2 applied to cultured podocytes was internalized and then activated p38? MAPK and c-Jun N-terminal kinase (JNK), important signaling steps in cell differentiation and apoptosis. Stx2 also activated caspase 3, resulting in an increased level of apoptosis. Coincubation of podocytes with SAP and Stx2 mitigated the effects of Stx2 and induced upregulation of antiapoptotic Bcl2. These data suggest that podocytes are a target of Stx2 and that SAP protects podocytes against Stx2-induced injury. SAP may therefore be a useful therapeutic option. PMID:24566618

Dettmar, Anne K; Binder, Elisabeth; Greiner, Friederike R; Liebau, Max C; Kurschat, Christine E; Jungraithmayr, Therese C; Saleem, Moin A; Schmitt, Claus-Peter; Feifel, Elisabeth; Orth-Höller, Dorothea; Kemper, Markus J; Pepys, Mark; Würzner, Reinhard; Oh, Jun

2014-05-01

34

C-reactive protein and serum amyloid A as early-phase and prognostic indicators of acute radiation exposure in nonhuman primate total-body irradiation model  

Energy Technology Data Exchange (ETDEWEB)

Terrorist radiological attacks or nuclear accidents could expose large numbers of people to ionizing radiation. In mass-casualty radiological incidents early medical-management requires triage tools for first-responders to quantitatively identify individuals exposed to life-threatening radiation doses and for early initiation (i.e., within one day after radiation exposure) of cytokine therapy for treatment of bone marrow acute radiation syndrome. Herein, we present results from 30 rhesus macaques total-body irradiated (TBI) to a broad dose range of 1-8.5 Gy with {sup 60}Co {gamma}-rays (0.55 Gy min{sup -1}) and demonstrate dose- and time-dependent changes in blood of C-reactive protein (CRP), serum amyloid A (SAA), and interleukin 6 (IL-6) measured by enzyme linked immunosorbent assay (ELISA). CRP and SAA dose-response results are consistent with {approx}1 Gy and {approx}0.2 Gy thresholds for photon-exposure at 24 h after TBI, respectively. Highly significant elevations of CRP and SAA (p = 0.00017 and p = 0.0024, respectively) were found in animal plasma at 6 h after all TBI doses suggesting their potential use as early-phase biodosimeters. Results also show that the dynamics and content of CRP and SAA levels reflect the course and severity of the acute radiation sickness (ARS) and may function as prognostic indicators of ARS outcome. These results demonstrate proof-of-concept that these radiation-responsive proteins show promise as a complementary approach to conventional biodosimetry for early assessment of radiation exposures and may also contribute as diagnostic indices in the medical management of radiation accidents.

Ossetrova, N.I., E-mail: ossetrova@afrri.usuhs.mil [Armed Forces Radiobiology Research Institute, 8901 Wisconsin Avenue, Bldg. 42, Bethesda, MD 20889-5603 (United States); Sandgren, D.J.; Blakely, W.F. [Armed Forces Radiobiology Research Institute, 8901 Wisconsin Avenue, Bldg. 42, Bethesda, MD 20889-5603 (United States)

2011-09-15

35

Purification, subunit characterization and ultrastructure of three soluble bovine lectins: conglutinin, mannose-binding protein and the pentraxin serum amyloid P-component.  

DEFF Research Database (Denmark)

Conglutinin and mannose-binding protein (MBP) are members of the C-type lectins which are widely present in mammalian plasma. Serum amyloid P-component (SAP) is a member of the pentraxin family with lectin properties. A scheme for the partial purification of all three lectins by carbohydrate affinity chromatography and selective elution was developed. The purification was monitored by SDS-PAGE, Western blotting and electron microscopy. Binding of the lectins to Sephadex-iC3b, their collagenase sensitivity, and the size and antibody reactivity of their subunits was investigated. The demonstration, by SDS-PAGE, of 25-kDa subunits, which were unaffected by collagenase treatment but bound to Sephadex-iC3b and antibodies to human SAP, indicated the existence of bovine SAP. Bovine conglutinin (BK) also showed calcium-dependent binding to Sephadex-iC3b, whereas bovine MBP did not. The binding of BK was inhibitable with GlcNAc. A 3000-fold increase in BK activity (ELISA) was obtained in eluates from Sephadex-iC3b. SDS-PAGE analyses of BK and MBP revealed subunits with an Mr of 43 kDa and 30 kDa, respectively. These subunits were sensitive to collagenase treatment which reduced the Mr to 20 kDa. Electron micrographs revealed a prominent flexible tetramer molecule (diameter 96 nm) in the BK preparations, a predominantly hexameric structure (diameter 30 nm) in the MBP preparations, and single annular pentameric disc-like molecules (diameter 11 nm) in the SAP preparations.

Andersen, Ove; Friis, P

1992-01-01

36

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

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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...

2010-01-01

37

Autoantibodies against protective molecules--C1q, C-reactive protein, serum amyloid P, mannose-binding lectin, and apolipoprotein A1: prevalence in systemic lupus erythematosus.  

Science.gov (United States)

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the production of several autoantibodies. Among the multiple factors involved in SLE development, apoptotic defects and impaired clearance of cellular debris have gained considerable interest, as they contribute to autoantigen overload. Several molecules of the innate immunity, also participate in the removal of damaged and apoptotic cells. Among them are C1q, C-reactive protein (CRP), serum amyloid P protein (SAP), mannose-binding lectin (MBL), and apolipoprotein A1 (APO A1). To evaluate the prevalence of autoantibodies against CRP, SAP, MBL, APO A1, and C1q among SLE patients, and their relationship with disease activity, a total of 150 SLE patients were screened for the presence of elevated antibody titers against C1q, CRP, SAP, MBL, and APO A1, utilizing the enzyme-linked immunosorbent assay (ELISA) method. Disease activity was assessed using the ECLAM or SLEDAI scores. The study population comprised two groups of patients: 100 patients with quiescent disease (median ECLAM score 2) comprised the first group, and 50 patients with active disease (median SLEDAI score 16) comprised group 2. Elevated titers of anti-CRP antibodies were significantly elevated only in group 1 (10% versus 4% of controls). Antibodies against SAP were evaluated only among patients in group 1, and were found at a significant high prevalence (20%). Elevated titers of anti-MBL antibodies were significantly elevated only in group 1 (15% versus 3.6%); and antibodies directed against APO A1 were significantly elevated in 21% of group 1, and 50% of group 2 patients. Elevated titers of anti-C1q were evaluated only in group 2, and were found at a significant prevalence of 66%. Significant correlation with disease activity was found only for anti-APO A1 antibodies, and only in group 1. Several patients harbored more than one of the autoantibodies tested. In patients with SLE, autoantibodies directed against protective molecules, that is, acute-phase proteins involved in the disposal of cellular and nuclear debris, can be detected. These autoantibodies may play a pathogenic role in the development or perpetuation of autoimmunity in SLE. PMID:17899624

Shoenfeld, Yehuda; Szyper-Kravitz, Martine; Witte, Torsten; Doria, Andrea; Tsutsumi, Akito; Tatsuya, Abe; Dayer, Jean-Michel; Roux-Lombard, Pascale; Fontao, Lionel; Kallenberg, Cees G M; Bijl, Marc; Matthias, Torsten; Fraser, Abigail; Zandman-Goddard, Gisele; Blank, Miri; Gilburd, Boris; Meroni, Pier Luigi

2007-06-01

38

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

39

Serum amyloid A in uremic HDL promotes inflammation.  

Science.gov (United States)

Uremia impairs the atheroprotective properties of HDL, but the mechanisms underlying why this occurs are unknown. Here, we observed that HDL isolated from healthy individuals inhibited the production of inflammatory cytokines by peripheral monocytes stimulated with a Toll-like receptor 2 agonist. In contrast, HDL isolated from the majority of patients with ESRD did not show this anti-inflammatory property; many HDL samples even promoted the production of inflammatory cytokines. To investigate this difference, we used shotgun proteomics to identify 49 HDL-associated proteins in a uremia-specific pattern. Proteins enriched in HDL from patients with ESRD (ESRD-HDL) included surfactant protein B (SP-B), apolipoprotein C-II, serum amyloid A (SAA), and ?-1-microglobulin/bikunin precursor. In addition, we detected some ESRD-enriched proteins in earlier stages of CKD. We did not detect a difference in oxidation status between HDL isolated from uremic and healthy patients. Regarding function of these uremia-specific proteins, only SAA mimicked ESRD-HDL by promoting inflammatory cytokine production. Furthermore, SAA levels in ESRD-HDL inversely correlated with its anti-inflammatory potency. In conclusion, HDL has anti-inflammatory activities that are defective in uremic patients as a result of specific changes in its molecular composition. These data suggest a potential link between the high levels of inflammation and cardiovascular mortality in uremia. PMID:22282592

Weichhart, Thomas; Kopecky, Chantal; Kubicek, Markus; Haidinger, Michael; Döller, Dominik; Katholnig, Karl; Suarna, Cacang; Eller, Philipp; Tölle, Markus; Gerner, Christopher; Zlabinger, Gerhard J; van der Giet, Markus; Hörl, Walter H; Stocker, Roland; Säemann, Marcus D

2012-05-01

40

A serum amyloid P-binding hydrogel speeds healing of partial thickness wounds in pigs  

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During wound healing, some circulating monocytes enter the wound, differentiate into fibroblast-like cells called fibrocytes, and appear to then further differentiate into myofibroblasts, cells that play a key role in collagen deposition, cytokine release, and wound contraction. The differentiation of monocytes into fibrocytes is inhibited by the serum protein serum amyloid P (SAP). Depleting SAP at a wound site thus might speed wound healing. SAP binds to some types of agarose in the presenc...

2009-01-01

 
 
 
 
41

Isolation and Functional Characterization of cDNA of Serum Amyloid A-Activating Factor That Binds to the Serum Amyloid A Promoter  

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Serum amyloid A (SAA), a plasma protein inducible in response to many inflammatory conditions, is associated with the pathogenesis of several diseases including reactive amyloidosis, rheumatoid arthritis, and atherosclerosis. We have previously reported an element of the SAA promoter, designated SAA-activating sequence (SAS), that is involved in the inflammation-induced SAA expression, and a nuclear factor, SAS-binding factor (SAF), that interacts with the SAS element has been identified prev...

Ray, Alpana; Ray, Bimal K.

1998-01-01

42

Serum Amyloid P Therapeutically Attenuates Murine Bleomycin-Induced Pulmonary Fibrosis via Its Effects on Macrophages  

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Macrophages promote tissue remodeling but few mechanisms exist to modulate their activity during tissue fibrosis. Serum amyloid P (SAP), a member of the pentraxin family of proteins, signals through Fc? receptors which are known to affect macrophage activation. We determined that IPF/UIP patients have increased protein levels of several alternatively activated pro-fibrotic (M2) macrophage-associated proteins in the lung and monocytes from these patients show skewing towards an M2 macrophage ...

Murray, Lynne A.; Rosada, Rogerio; Moreira, Ana Paula; Joshi, Amrita; Kramer, Michael S.; Hesson, David P.; Argentieri, Rochelle L.; Mathai, Susan; Gulati, Mridu; Herzog, Erica L.; Hogaboam, Cory M.

2010-01-01

43

Antibody-Array Interaction Mapping, a New Method to Detect Protein Complexes Applied to the Discovery and Study of Serum Amyloid P Interactions with Kininogen in Human Plasma*  

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Protein-protein interactions are fundamentally important in biological processes, but the existing analytical tools have limited ability to sensitively and precisely measure the dynamic composition of protein complexes in biological samples. We report here the development of antibody-array interaction mapping (AAIM) to address that need. We used AAIM to probe interactions among a set of 48 proteins in serum and found several known interactions as well potentially novel interactions, including...

Bergsma, Derek; Chen, Songming; Buchweitz, John; Gerszten, Robert; Haab, Brian B.

2010-01-01

44

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

45

Multiphoton absorption in amyloid protein fibres  

Science.gov (United States)

Fibrillization of peptides leads to the formation of amyloid fibres, which, when in large aggregates, are responsible for diseases such as Alzheimer's and Parkinson's. Here, we show that amyloids have strong nonlinear optical absorption, which is not present in native non-fibrillized protein. Z-scan and pump-probe experiments indicate that insulin and lysozyme ?-amyloids, as well as ?-synuclein fibres, exhibit either two-photon, three-photon or higher multiphoton absorption processes, depending on the wavelength of light. We propose that the enhanced multiphoton absorption is due to a cooperative mechanism involving through-space dipolar coupling between excited states of aromatic amino acids densely packed in the fibrous structures. This finding will provide the opportunity to develop nonlinear optical techniques to detect and study amyloid structures and also suggests that new protein-based materials with sizable multiphoton absorption could be designed for specific applications in nanotechnology, photonics and optoelectronics.

Hanczyc, Piotr; Samoc, Marek; Norden, Bengt

2013-12-01

46

Determination of serum amyloid P component in seminal plasma and correlations with serum hormone levels in young, healthy men.  

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Abstract Serum amyloid P component (SAP) belongs to the pentraxin family of proteins. SAP is evolutionary conserved, and involved in amyloidosis, innate immunity, inflammation, and apoptosis. We have previously described SAP in the male reproductive tract, where it occurs in seminal fluid, on spermatozoa, and in epididymal, seminal vesicle, and prostate tissue. In the present investigation, our aim was to characterize SAP in male reproduction. In short, we developed and evaluated an immunoass...

Sonesson, Annika; Hillarp, Andreas; Giwercman, Aleksander; Malm, Johan

2011-01-01

47

Human serum amyloid P component is a single uncomplexed pentamer in whole serum.  

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BACKGROUND: Serum amyloid P component (SAP) is a universal constituent of amyloid deposits and contributes to their pathogenesis. SAP also has important normal functions in the handling of chromatin in vivo and resistance to bacterial infection. The atomic resolution crystal structure of SAP is known, but its physiological oligomeric assembly remains controversial. In the absence of calcium, isolated human SAP forms stable decamers composed of two cyclic disk-like pentamers interacting face t...

2000-01-01

48

Human serum amyloid P component is a single uncomplexed pentamer in whole serum  

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Background: Serum amyloid P component (SAP) is a universal constituent of amyloid deposits and contributes to their pathogenesis. SAP also has important normal functions in the handling of chromatin in vivo and resistance to bacterial infection. The atomic resolution crystal structure of SAP is known, but its physiological oligomeric assembly remains controversial. In the absence of calcium, isolated human SAP forms stable decamers composed of two cyclic disk-like pentamers interacting face t...

2000-01-01

49

C-reactive protein, haptoglobin, serum amyloid A and pig major acute phase protein response in pigs simultaneously infected with H1N1 swine influenza virus and Pasteurella multocida  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Swine influenza (SI is an acute respiratory disease caused by swine influenza virus (SIV. Swine influenza is generally characterized by acute onset of fever and respiratory symptoms. The most frequent complications of influenza are secondary bacterial pneumonia. The objective of this work was to study the acute phase proteins (APP responses after coinfection of piglets with H1N1 swine influenza virus (SwH1N1 and Pasteurella multocida (Pm in order to identify whether the individual APP response correlate with disease severity and whether APP could be used as markers of the health status of coinfected pigs. Results In all coinfected pigs clinical sings, including fever, coughing and dyspnea, were seen. Viral shedding was observed from 2 to 7 dpi. The mean level of antibodies against Pm dermonecrotoxin in infected piglets increase significantly from 7 dpi. Anti-SwH1N1 antibodies in the serum were detected from 7 dpi. The concentration of C-reactive protein (CRP increased significantly at 1 dpi as compared to control pigs, and remained significantly higher to 3 dpi. Level of serum amyloid A (SAA was significantly higher from 2 to 3 dpi. Haptoglobin (Hp was significantly elevated from 3 dpi to the end of study, while pig major acute phase protein (Pig-MAP from 3 to 7 dpi. The concentrations of CRP, Hp and SAA significantly increased before specific antibodies were detected. Positive correlations were found between serum concentration of Hp and SAA and lung scores, and between clinical score and concentrations of Pig-MAP and SAA. Conclusions The results of current study confirmed that monitoring of APP may revealed ongoing infection, and in this way may be useful in selecting clinically healthy pigs (i.e. before integration into an uninfected herd. Present results corroborated our previous findings that SAA could be a potentially useful indicator in experimental infection studies (e.g. vaccine efficiency investigations or as a marker for disease severity, because of correlation observed between its concentration in serum and disease severity (lung scores, clinical scores.

Pomorska-Mól Ma?gorzata

2013-01-01

50

Amyloid peptides and proteins in review.  

Science.gov (United States)

Amyloids are filamentous protein deposits ranging in size from nanometres to microns and composed of aggregated peptide beta-sheets formed from parallel or anti-parallel alignments of peptide beta-strands. Amyloid-forming proteins have attracted a great deal of recent attention because of their association with over 30 diseases, notably neurodegenerative conditions like Alzheimer's, Huntington's, Parkinson's, Creutzfeldt-Jacob and prion disorders, but also systemic diseases such as amyotrophic lateral sclerosis (Lou Gehrig's disease) and type II diabetes. These diseases are all thought to involve important conformational changes in proteins, sometimes termed misfolding, that usually produce beta-sheet structures with a strong tendency to aggregate into water-insoluble fibrous polymers. Reasons for such conformational changes in vivo are still unclear. Intermediate aggregated state(s), rather than precipitated insoluble polymeric aggregates, have recently been implicated in cellular toxicity and may be the source of aberrant pathology in amyloid diseases. Numerous in vitro studies of short and medium length peptides that form amyloids have provided some clues to amyloid formation, with an alpha-helix to beta-sheet folding transition sometimes implicated as an intermediary step leading to amyloid formation. More recently, quite a few non-pathological amyloidogenic proteins have also been identified and physiological properties have been ascribed, challenging previous implications that amyloids were always disease causing. This article summarises a great deal of current knowledge on the occurrence, structure, folding pathways, chemistry and biology associated with amyloidogenic peptides and proteins and highlights some key factors that have been found to influence amyloidogenesis. PMID:17846922

Harrison, R S; Sharpe, P C; Singh, Y; Fairlie, D P

2007-01-01

51

Serum amyloid P ameliorates radiation-induced oral mucositis and fibrosis  

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Abstract Purpose To evaluate the effect of the anti-fibrotic protein serum amyloid P (SAP) on radiation-induced oral mucositis (OM) and fibrosis in a hamster cheek-pouch model. Experimental Design Hamsters received a single dose of radiation (40 Gy) to the left everted cheek pouch to induce significant OM. The protective therapeutic potential of SAP was evaluated using varying dosing regimens. The extent of OM was measured using a validated six-point scoring sch...

Murray Lynne A; Kramer Michael S; Hesson David P; Watkins Brynmor A; Fey Edward G; Argentieri Rochelle L; Shaheen Furquan; Knight Darryl A; Sonis Stephen T

2010-01-01

52

Biofilm inhibitors that target amyloid proteins.  

Science.gov (United States)

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 antiamyloid activity. We identified two molecules, AA-861 and parthenolide, which efficiently inhibited biofilms by preventing the formation of amyloid-like fibers. Parthenolide also disrupted pre-established biofilms. These molecules also impeded the formation of biofilms of other bacterial species that secrete amyloid proteins, such as Bacillus cereus and Escherichia coli. Furthermore, the identified molecules decreased the conversion of the yeast protein New1 to the prion state in a heterologous host, indicating the broad range of activity of the molecules. PMID:23352144

Romero, Diego; Sanabria-Valentín, Edgardo; Vlamakis, Hera; Kolter, Roberto

2013-01-24

53

Human serum amyloid A genes are expressed in monocyte/macrophage cell lines.  

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Serum amyloid A (apoSAA) is a family of proteins found, mainly associated with high density lipoproteins, in the blood plasma of mammals and at least one avian species, the Pekin duck. These proteins are present in small amounts under normal circumstances, but their concentration is capable of rising 100- to 1,000-fold in situations involving tissue injury or infection. Like classic acute phase proteins they are produced in the liver; however, expression of one of the apoSAA genes is known to...

1994-01-01

54

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

55

Interaction between amyloid precursor protein and Nogo receptors regulates amyloid deposition  

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Excessive production or accumulation of ?-amyloid (A?) peptides in human brains leads to increased amyloid deposition and cognitive dysfunction, which are invariable pathological features in patients with Alzheimer's disease (AD). Many cellular factors can regulate the production of A?. In this study, we show that a family of proteins named Nogo receptor proteins (NgR1 to NgR3) regulates A? production via interaction with amyloid precursor protein (APP). Further mapping of the interacting...

Zhou, Xiangdong; Hu, Xiangyou; He, Wanxia; Tang, Xiaoying; Shi, Qi; Zhang, Zhuohua; Yan, Riqiang

2011-01-01

56

Protective molecules--C-reactive protein (CRP), serum amyloid P (SAP), pentraxin3 (PTX3), mannose-binding lectin (MBL), and apolipoprotein A1 (Apo A1), and their autoantibodies: prevalence and clinical significance in autoimmunity.  

Science.gov (United States)

Apoptotic defects and impaired clearance of cellular debris are considered key events in the development of autoimmunity, as they can contribute to autoantigen overload, and may initiate an autoimmune response. The pentraxins are a group of highly conserved proteins including the short pentraxins, C-reactive protein (CRP) and serum amyloid-P (SAP), and the long pentraxin-3 (PTX3), which are all involved in innate immunity and in acute-phase responses. Mannan-binding lectin (MBL) is an activator of the complement system, and Apolipoprotein A-1 (Apo A-1) is pivotal in the cholesterol homeostasis and has anti-inflammatory properties. In addition to their role in innate immunity and inflammation, each of these five proteins participates in the removal of damaged and apoptotic cells. In this review, we discuss the clinical significance of different levels of these proteins, their role in the induction or protection from autoimmunity, and the presence of specific autoantibodies against them in the different autoimmune diseases. PMID:16380821

Kravitz, Martine Szyper; Pitashny, Milena; Shoenfeld, Yehuda

2005-11-01

57

Generation of Amyloid-? Is Reduced by the Interaction of Calreticulin with Amyloid Precursor Protein, Presenilin and Nicastrin  

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Dysregulation of the proteolytic processing of amyloid precursor protein by ?-secretase and the ensuing generation of amyloid-? is associated with the pathogenesis of Alzheimer's disease. Thus, the identification of amyloid precursor protein binding proteins involved in regulating processing of amyloid precursor protein by the ?-secretase complex is essential for understanding the mechanisms underlying the molecular pathology of the disease. We identified calreticulin as novel amyloid prec...

Stemmer, Nina; Strekalova, Elena; Djogo, Nevena; Plo?ger, Frank; Loers, Gabriele; Lutz, David; Buck, Friedrich; Michalak, Marek; Schachner, Melitta; Kleene, Ralf

2013-01-01

58

The Effect of Storage Temperature and Time on the Concentrations of Bovine Serum Amyloid A and Its Mammary Associated Isoform  

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The objective of this study was to evaluate the effect of storage under various conditions on the concentrations of major bovine acute phase protein—serum amyloid A, and its mammary isoform. Blood samples were taken from seven clinically healthy calves, and milk samples from six clinically healthy dairy cows. The harvested blood serum and the milk samples were fractioned into aliquots. One aliquot was analyzed on the day of collection without storage. The second aliquots were stored at 4°C...

2012-01-01

59

Apple Procyanidins Suppress Amyloid ?-Protein Aggregation  

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Procyanidins (PCs) are major components of the apple polyphenols (APs). We previously reported that treatment with PC extended the mean lifespan of Caenorhabditis elegans (Sunagawa et al., 2011). In order to estimate the neuroprotective effects of PC, we investigated the antiaggregative activity of PC on amyloid ?-protein (A?) aggregation, which is a pathological hallmark of Alzheimer's disease. We herein report that PC significantly suppressed A?42 aggregation and dissociated A?42 aggreg...

2011-01-01

60

Metabolic studies of radioiodinated serum amyloid P component in normal subjects and patients with systemic amyloidosis.  

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125I-Serum amyloid P component (SAP), injected intravenously into 10 normal subjects, remained predominantly intravascular with mean (SD) T1/2 (half time) in plasma of 24.5 (5.9) h. The fractional catabolic rate of 68 (19)% of the plasma pool per day was more rapid than other reported human plasma proteins. All radioactivity was excreted in the urine by 14 d. In 16 patients with monoclonal gammopathy or chronic inflammatory diseases, but without amyloidosis, 125I-SAP metabolism was normal. Ho...

Hawkins, P. N.; Wootton, R.; Pepys, M. B.

1990-01-01

 
 
 
 
61

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

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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

62

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. "1"2"5I-Clq was retained on the Sepharose when purified "1"2"5I-Clq was incubated with SAP prior to affinity chromatography on Sepharose. In the absence of SAP, the "1"2"5I-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, "1"2"5I-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 role in the regulation of complement via the classical pathway

1986-01-01

63

Role of serum amyloid P component in immune clearance  

Energy Technology Data Exchange (ETDEWEB)

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. /sup 125/I-Clq was retained on the Sepharose when purified /sup 125/I-Clq was incubated with SAP prior to affinity chromatography on Sepharose. In the absence of SAP, the /sup 125/I-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, /sup 125/I-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 role in the regulation of complement via the classical pathway.

Bristow, D.L.

1986-01-01

64

Overexpression of Monocyte Chemotactic Protein-1/CCL2 in ?-Amyloid Precursor Protein Transgenic Mice Show Accelerated Diffuse ?-Amyloid Deposition  

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Microglia accumulation at the site of amyloid plaques is a strong indication that microglia play a major role in Alzheimer’s disease pathogenesis. However, how microglia affect amyloid-? peptide (A?) deposition remains poorly understood. To address this question, we developed a novel bigenic mouse that overexpresses both amyloid precursor protein (APP) and monocyte chemotactic protein-1 (MCP-1; CCL2 in systematic nomenclature). CCL2 expression, driven by the glial fibrillary acidic protei...

2005-01-01

65

Amyloid precursor protein and neural development.  

Science.gov (United States)

Interest in the amyloid precursor protein (APP) has increased in recent years due to its involvement in Alzheimer's disease. Since its molecular cloning, significant genetic and biochemical work has focused on the role of APP in the pathogenesis of this disease. Thus far, however, these studies have failed to deliver successful therapies. This suggests that understanding the basic biology of APP and its physiological role during development might be a crucial missing link for a better comprehension of Alzheimer's disease. Here, we present an overview of some of the key studies performed in various model organisms that have revealed roles for APP at different stages of neuronal development. PMID:24961795

Nicolas, Maya; Hassan, Bassem A

2014-07-01

66

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

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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 ...

Rm, Eckhardt Erik; Witta Jassir; Zhong Jian; Arsenescu Razvan; Arsenescu Violeta; Wang Yu; Ghoshal Sarbani; de Beer Marcielle C; de Beer Frederick C; Js, Villiers Willem

2010-01-01

67

Sonication of proteins causes formation of aggregates that resemble amyloid  

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Despite the widespread use of sonication in medicine, industry, and research, the effects of sonication on proteins remain poorly characterized. We report that sonication of a range of structurally diverse proteins results in the formation of aggregates that have similarities to amyloid aggregates. The formation of amyloid is associated with, and has been implicated in, causing of a wide range of protein conformational disorders including Alzheimer’s disease, Huntington’s disease, Parkins...

2004-01-01

68

Statistical Mechanical Treatments of Protein Amyloid Formation  

Directory of Open Access Journals (Sweden)

Full Text Available 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 amount of fibrils formed, as a function of initial protein concentration. Furthermore, statistical mechanics models can be used to fit experimental data when they are available for comparison.

John S. Schreck

2013-08-01

69

Influenza virus infection is not affected by serum amyloid P component  

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Background: Binding of serum amyloid P component (SAP) to its ligands, including bacteria, chromatin and amyloid fibrils, protects them from degradation, is antiopsonic and anti-immunogenic. SAP thereby enhances the virulence of pathogenic bacteria to which it binds. However SAP also contributes to host resistance against bacteria to which it does not bind. Human SAP has been reported to bind to the influenza virus and inhibit viral invasion of cells in tissue culture. We therefore investigat...

2002-01-01

70

Influenza virus infection is not affected by serum amyloid P component.  

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BACKGROUND: Binding of serum amyloid P component (SAP) to its ligands, including bacteria, chromatin and amyloid fibrils, protects them from degradation, is anti-opsonic and anti-immunogenic. SAP thereby enhances the virulence of pathogenic bacteria to which it binds. However SAP also contributes to host resistance against bacteria to which it does not bind. Human SAP has been reported to bind to the influenza virus and inhibit viral invasion of cells in tissue culture. We therefore investiga...

2002-01-01

71

Serum amyloid A as a potent therapeutic marker in a refractory patient with polymyalgia rheumatica.  

Science.gov (United States)

We report a patient with polymyalgia rheumatica (PMR) who showed a relapse soon after tapering of oral prednisolone. C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were quickly normalized after the re-increase in oral prednisolone, and muscle pain and stiffness gradually improved in parallel with a decrease in serum amyloid A (SAA). Flow cytometry simultaneously demonstrated an increase in CD8+CD25+ cells and a decrease in CD4+CD25+ cells and CD4+CD45RA+ cells. When clinical symptoms remain with negative results for CRP and ESR even after the start of corticosteroid treatment, SAA might be a potent therapeutic marker for disease activity in PMR. PMID:16258224

Shimojima, Yasuhiro; Matsuda, Masayuki; Gono, Takahisa; Ishii, Wataru; Ikeda, Shu-Ichi

2005-09-01

72

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

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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 ab...

2004-01-01

73

?-amyloid oligomers and prion protein: Fatal attraction?  

Science.gov (United States)

The relationship between Alzheimer disease (AD) and prion-related encephalopathies (TSE) has been proposed by different points of view. Recently, the scientific attention has been attracted by the results proposing the possibility that PrPc, the protein whose pathologic form is responsible of TSE, can mediated the toxic effect of ? amyloid (A?) oligomers. The oligomers are considered the culprit of the neurodegenerative process associated to AD, although the pathogenic mechanism activated by these small aggregates remain to be elucidated. In the initial study based on the binding screening PrPc was identified as ligand /receptor of A? oligomers, while long term potentiation (LTP) analysis in vitro and behavioural studies in vivo, demonstrated that the absence of PrPc abolished the damage induced by A? oligomers. The high affinity binding A? oligomers-PrPc has been confirmed, whereas a functional role of this association has been excluded by three different studies. We approached this issue by the direct application of A? oligomers in the brain followed by the behavioural examination of memory deficits. Our data using PrP knock-out mice suggest that A? 1-42 oligomers are responsible for cognitive impairment in AD but PrPc is not required for their effect. Similarly, in two other studies the LTP alterations induced by A? 1-42 oligomers was not influenced by the absence of PrP. Possible explanations of these contradictory results are discussed. PMID:21150333

Forloni, Gianluigi; Balducci, Claudia

2011-01-01

74

Expression of apolipoprotein serum amyloid A mRNA in human atherosclerotic lesions and cultured vascular cells: implications for serum amyloid A function.  

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Altered lipoprotein metabolism and vascular injury are considered to be major parts of the pathogenesis of atherosclerotic lesions. Serum amyloid A (SAA) is a family of acute-phase reactants found residing mainly on high density lipoproteins (HDL) in the circulation. Several functions for the SAAs have been proposed that could be important in atherosclerosis. These include involvement in cholesterol metabolism, participation in detoxification, depression of immune responses, and interference ...

Meek, R. L.; Urieli-shoval, S.; Benditt, E. P.

1994-01-01

75

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

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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

76

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

2013-03-01

77

Kinetics of local and systemic isoforms of serum amyloid A in bovine mastitic milk  

DEFF Research Database (Denmark)

The aim of the present study was to characterise the serum amyloid A (SAA) response to intramammary inoculation of Escherichia coli and to examine the distribution of hepatically and extrahepatically pruduced SAA isoforms in plasma and milk fra cows with mastitis.

Jacobsen, Stine; Niewold, T.A.

2005-01-01

78

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

79

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

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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

80

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

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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

 
 
 
 
81

Modification of a small ?-barrel protein, to give pseudo-amyloid structures, inhibits amyloid ?-peptide aggregation.  

Science.gov (United States)

Aggregation of amyloid ?-peptide (A?) is closely related to the pathogenesis of Alzheimer's disease (AD). Although much effort has been devoted to the construction of molecules that inhibit the aggregation of A?1-42, high doses are needed for the inhibition of A? aggregation in many cases. Previously, we reported that designed green fluorescent protein (GFP) analogues that gives pseudo-A? ?-sheet structures can work as an aggregation inhibitor against A?. To further test this design strategy, we constructed protein analogues that mimic A? ?-sheet structures of amyloids by using insulin-like growth factor 2 receptor domain 11 (IGF2R-d11) as a scaffold. A designed protein, named IG11KK, which has a parallel configuration of A?-like ? sheets, can bind more preferentially to oligomeric A?1-42 than the monomer. Moreover, IG11KK suppressed the aggregation of A?1-42 efficiently, even though lower concentrations of IG11KK than A? were used. The aggregation kinetics of A? in the presence of the designed proteins revealed that IG11KK can work as an inhibitor not only for the early to middle stages, but also in the latter stage of A? aggregation owing to its favorable binding to oligomeric structures of A?. The design strategy using ?-barrel proteins such as IGF2R-d11 and GFP is useful in generating excellent inhibitors of protein misfolding and amyloid formation. PMID:23371795

Murakoshi, Yuko; Takahashi, Tsuyoshi; Mihara, Hisakazu

2013-04-01

82

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

83

Modeling of chemical inhibition from amyloid protein aggregation kinetics  

Science.gov (United States)

Backgrounds The process of amyloid proteins aggregation causes several human neuropathologies. In some cases, e.g. fibrillar deposits of insulin, the problems are generated in the processes of production and purification of protein and in the pump devices or injectable preparations for diabetics. Experimental kinetics and adequate modelling of chemical inhibition from amyloid aggregation are of practical importance in order to study the viable processing, formulation and storage as well as to predict and optimize the best conditions to reduce the effect of protein nucleation. Results In this manuscript, experimental data of insulin, A?42 amyloid protein and apomyoglobin fibrillation from recent bibliography were selected to evaluate the capability of a bivariate sigmoid equation to model them. The mathematical functions (logistic combined with Weibull equation) were used in reparameterized form and the effect of inhibitor concentrations on kinetic parameters from logistic equation were perfectly defined and explained. The surfaces of data were accurately described by proposed model and the presented analysis characterized the inhibitory influence on the protein aggregation by several chemicals. Discrimination between true and apparent inhibitors was also confirmed by the bivariate equation. EGCG for insulin (working at pH?=?7.4/T?=?37°C) and taiwaniaflavone for A?42 were the compounds studied that shown the greatest inhibition capacity. Conclusions An accurate, simple and effective model to investigate the inhibition of chemicals on amyloid protein aggregation has been developed. The equation could be useful for the clear quantification of inhibitor potential of chemicals and rigorous comparison among them.

2014-01-01

84

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

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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...

2009-01-01

85

Why working with porcine circulating serum amyloid A is a pig of a job.  

Science.gov (United States)

Serum amyloid A (SAA) is a major acute phase protein in most species, and is widely employed as a health marker. Systemic SAA isoforms (SAA1, and SAA2) are apolipoproteins synthesized by the liver which associate with high density lipoproteins (HDL). Local SAA (SAA3) isoforms are synthesized in other tissues and are present in colostrums, mastitic milk and mammary dry secretions. Of systemic SAA the bulk is monomeric and bound to HDL, and a small proportion is found in serum in a multimeric form with a buried HDL binding site. In most species, systemic SAA could easily be studied by purifying it from serum of diseased individuals by hydrophobic interaction chromatography methods. For years, we were not able to isolate systemic pig SAA using the latter methods, and found that the bulk of pig SAA did not reside in the HDL-rich serum fractions but in the soluble protein fraction mainly as a multimeric protein. Based on these surprising results, we analysed in silico the theoretical properties and predicted the secondary structure of pig SAA by using the published pig primary SAA amino acid sequence. Results of the analysis confirmed that systemic pig SAA had the highest homology with local SAA3 which in other species is the isoform associated with non-hepatic production in tissues such as mammary gland and intestinal epithelium. Furthermore, the primary sequence of the pig SAA N-terminal HDL binding site did differ considerably from SAA1/2. Secondary structure analysis of the predicted alpha-helical structure of this HDL binding site showed a considerable reduction in hydrophobicity compared to SAA1/2. Based on these results, it is argued that systemic acute phase SAA in the pig has the structural properties of locally produced SAA (SAA3). It is proposed that in pig SAA multimers the charged N-terminal sequence is buried, which would explain their different properties. It is concluded that pig systemic SAA is unique compared to other species, which raises questions about the proposed importance of acute phase SAA in HDL metabolism during inflammation in this species. PMID:23073471

Soler, L; Molenaar, A; Merola, N; Eckersall, P D; Gutiérrez, A; Cerón, J J; Mulero, V; Niewold, T A

2013-01-21

86

Zn2+ interaction with Alzheimer amyloid beta protein calcium channels.  

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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...

1996-01-01

87

Commensal microbiota stimulate systemic neutrophil migration through induction of Serum amyloid A.  

Science.gov (United States)

Neutrophils serve critical roles in inflammatory responses to infection and injury, and mechanisms governing their activity represent attractive targets for controlling inflammation. The commensal microbiota is known to regulate the activity of neutrophils and other leucocytes in the intestine, but the systemic impact of the microbiota on neutrophils remains unknown. Here we utilized in vivo imaging in gnotobiotic zebrafish to reveal diverse effects of microbiota colonization on systemic neutrophil development and function. The presence of a microbiota resulted in increased neutrophil number and myeloperoxidase expression, and altered neutrophil localization and migratory behaviours. These effects of the microbiota on neutrophil homeostasis were accompanied by an increased recruitment of neutrophils to injury. Genetic analysis identified the microbiota-induced acute phase protein serum amyloid A (Saa) as a host factor mediating microbial stimulation of tissue-specific neutrophil migratory behaviours. In vitro studies revealed that zebrafish cells respond to Saa exposure by activating NF-?B, and that Saa-dependent neutrophil migration requires NF-?B-dependent gene expression. These results implicate the commensal microbiota as an important environmental factor regulating diverse aspects of systemic neutrophil development and function, and reveal a critical role for a Saa-NF-?B signalling axis in mediating neutrophil migratory responses. PMID:24373309

Kanther, Michelle; Tomkovich, Sarah; Xiaolun, Sun; Grosser, Melinda R; Koo, Jaseol; Flynn, Edward J; Jobin, Christian; Rawls, John F

2014-07-01

88

Serum amyloid P-component-induced enhancement of macrophage listericidal activity.  

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Purified serum amyloid P component (SAP), the major acute-phase reactant of mice, augmented the in vitro listericidal activity of inflammatory (elicited) macrophages, bone marrow-derived monocytes, and macrophages from a subcutaneous site of inflammation. Monocytes and macrophages from C57BL/B6 mice, which are relatively resistant to Listeria monocytogenes, exhibited a significantly greater enhanced killing capacity for listeria than macrophages from listeria-susceptible A/J mice. SAP did not...

Singh, P. P.; Gervais, F.; Skamene, E.; Mortensen, R. F.

1986-01-01

89

Accumulation and expression of serum amyloid P component in human atherosclerotic lesions  

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Serum amyloid P component (SAP) is a member of pentraxins. Previous studies indicate that SAP exists in human atherosclerotic aortic intima and the plasma SAP levels are associated with cardiovascular disease. In this study, we characterized SAP in normal and atherosclerotic intima, investigated the source of SAP in atherosclerotic lesions, and assessed the effect of SAP on HDL function. Immunohistochemical staining and electroimmunoassay indicated that SAP is not present in normal aortic int...

Song, Zhiqing; Cai, Lei; Guo, Ling; Tsukamoto, Yoshitane; Yutani, Chikao; Li, Xiang-an

2010-01-01

90

Serum potassium concentrations after suxamethonium in patients with familial amyloid polyneuropathy type I  

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BACKGROUND: Suxamethonium produces an abnormal increase in serum potassium in some neurological diseases and some authors have suggested that it is safer not to use this drug in patients with familial amyloid polyneuropathy (FAP). However, there are no data previously reported to support this hypothesis. The aim of this study was to evaluate the magnitude of the potassium increase produced by suxamethonium in FAP type I. METHOD: Twenty-one FAP Met 30 patients anaesthetised for liver trans...

Viana, Js; Neves, S.; Vieira, H.; Bento, C.; Perdigoto, R.; Furtado, Al

1997-01-01

91

Protein phosphatase 5 protects neurons against amyloid ? toxicity  

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Amyloid ? (A?) is thought to promote neuronal cell loss in Alzheimer’s disease (AD), in part through the generation of reactive oxygen species (ROS) and subsequent activation of mitogen-activated protein kinase (MAPK) pathways. Protein phosphatase 5 (PP5) is a ubiquitously expressed serine/threonine phosphatase which has been implicated in several cell stress response pathways and shown to inactivate MAPK pathways through key dephosphorylation events. Therefore we examined whether PP5 pro...

2009-01-01

92

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

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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

93

Impact of the Nature and Size of the Polymeric Backbone on the Ability of Heterobifunctional Ligands to Mediate Shiga Toxin and Serum Amyloid P Component Ternary Complex Formation  

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Inhibition of AB5-type bacterial toxins can be achieved by heterobifunctional ligands (BAITs) that mediate assembly of supramolecular complexes involving the toxin’s pentameric cell membrane-binding subunit and an endogenous protein, serum amyloid P component, of the innate immune system. Effective in vivo protection from Shiga toxin Type 1 (Stx1) is achieved by polymer-bound, heterobifunctional inhibitors-adaptors (PolyBAITs), which exhibit prolonged half-life in circulation and by mediati...

Kitov, Pavel I.; Eugenia Paszkiewicz; Sadowska, Joanna M.; Zhicheng Deng; Marya Ahmed; Ravin Narain; Griener, Thomas P.; Mulvey, George L.; Armstrong, Glen D.; Bundle, David R.

2011-01-01

94

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

1986-01-01

95

Characterization of the cheetah serum amyloid A1 gene: critical role and functional polymorphism of a cis-acting element.  

Science.gov (United States)

Amyloid A (AA) amyloidosis is one of the principal causes of morbidity and mortality in captive cheetahs (Acinonyx jubatus), which are in danger of extinction. For practical conservation of this species, therefore, it is critical to elucidate the etiology of AA amyloidosis, especially to understand the mechanisms of transcriptional regulation of serum amyloid A (SAA), a precursor protein of the AA protein. In this study, the structure and nucleotide sequence of the cheetah SAA1 gene including the 5'-flanking promoter/enhancer region was determined. Putative nuclear factor kappa-B (NF-kappaB) and CCAAT/enhancer binding protein beta (C/EBPbeta) cis-acting elements, which play key roles in SAA1 transcriptional induction in response to inflammation, were identified in the 5'-flanking region of the cheetah SAA1 gene. Fortuitously, a single nucleotide polymorphism was identified in the captive cheetah cohort in the putative NF-kappaB cis-acting element and had a remarkable effect on SAA1 transcriptional induction. These results provide a foundation not only for clarifying the etiology of AA amyloidosis in the cheetah but also for contriving a strategy for conservation of this species. PMID:18375929

Zhang, Beiru; Une, Yumi; Ge, Fengxia; Fu, Xiaoying; Qian, Jinze; Zhang, Pengyao; Sawashita, Jinko; Higuchi, Keiichi; Mori, Masayuki

2008-01-01

96

Structural dynamics of the amyloid ?-protein monomer folding nucleus  

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Alzheimer's disease (AD) is linked to the aberrant assembly of the amyloid ?-protein (A?). The 21AEDVGSNKGA30 segment, A?(21-30), forms a turn that acts as a monomer folding nucleus. Amino acid substitutions within this nucleus cause familial forms of AD. To determine the biophysical characteristics of the folding nucleus, we studied the biologically relevant acetyl-A?(21-30)-amide peptide using experimental techniques (limited proteolysis, thermal denaturation, urea denaturation followed...

Roychaudhuri, Robin; Yang, Mingfeng; Condron, Margaret M.; Teplow, David B.

2012-01-01

97

On the nucleation of amyloid ?-protein monomer folding  

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Neurotoxic assemblies of the amyloid ?-protein (A?) have been linked strongly to the pathogenesis of Alzheimer’s disease (AD). Here, we sought to monitor the earliest step in A? assembly, the creation of a folding nucleus, from which oligomeric and fibrillar assemblies emanate. To do so, limited proteolysis/mass spectrometry was used to identify protease-resistant segments within monomeric A?(1–40) and A?(1–42). The results revealed a 10-residue, protease-resistant segment, Ala21?...

Lazo, Noel D.; Grant, Marianne A.; Condron, Margaret C.; Rigby, Alan C.; Teplow, David B.

2005-01-01

98

Importance of the Caspase Cleavage Site in Amyloid-? Protein Precursor  

Science.gov (United States)

Reports from multiple laboratories have now been published analyzing the critical nature of the caspase cleavage site of amyloid-? protein precursor (A?PP) for cell death induction, synaptic loss, hippocampal atrophy, long-term potentiation, memory loss, neophobia, and other aspects of the Alzheimer’s phenotype. Here we review the results and implications of these studies for the understanding of Alzheimer’s disease pathophysiology and the potential development of therapeutics that target this site in A?PP.

Bredesen, Dale E.; John, Varghese; Galvan, Veronica

2014-01-01

99

Structure–neurotoxicity relationships of amyloid ?-protein oligomers  

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Amyloid ?-protein (A?) oligomers may be the proximate neurotoxins in Alzheimer's disease (AD). “Oligomer” is an ill-defined term because many kinds have been reported and they often exist in rapid equilibrium with monomers and higher-order assemblies. We report here results of studies in which specific oligomers have been stabilized structurally, fractionated in pure form, and then studied by using a combination of CD spectroscopy, Thioflavin T fluorescence, EM, atomic force microscopy ...

Ono, Kenjiro; Condron, Margaret M.; Teplow, David B.

2009-01-01

100

Maldi-Tof /Tof-MS Reveals Elevated Serum Haptoglobin and Amyloid A in Behcet's Disease  

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Behcet¿s disease (BD) is a multisystemic autoimmune disease with unclear etiology and pathogenesis. To screen aberrant serum proteins in BD, serum samples were obtained from eight male BD patients with active uveitis and eight male healthy volunteers with informed consent. The serum samples from active BD patients and normal controls were pooled. Highly abundant serum proteins (albumin and IgG) were depleted from these two samples using an affinity capture based kit. The obtained samples wer...

Mao, L.; Dong, H.; Yang, P.; Zhou, H.; Huang, X.; Lin, X.; Kijlstra, A.

2008-01-01

 
 
 
 
101

The Role of Phospholipase D in Amyloid Precursor Protein Processing  

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The generation of a secreted N-terminal fragment of the amyloid precursor protein (A PPs) can be stimulated by a variety of signaling pathways many of which are also known to modulate the activity of the phospholipase D (PLD) enzyme. This study used primary rat neuronal cerebellar granule (CG) cultures and SH-SY5Y human neuroblastoma cell lines to determine the potential role of PLD in the protein kinase C (PKC)-associated generation of A PPs. Protein release was markedly enhanced by direct P...

2005-01-01

102

Effect of progressive resistance training on serum amyloid A and apolipoprotein A-I levels in diabetic Rats  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Serum amyloid A (SAA is an acute-phase protein, which is a clinically useful marker of inflammation and associates strongly with increased risk of cardiovascular events. The purpose of this study was to investigate the effect of resistance training with progressive load on serum levels of SAA and apolipoprotein A-I (apoA-I in streptozotocin-induced diabetic rats.Materials and Methods: Twenty four male Wister rats (292 ± 20g were randomly divided into three groups: non-diabetic control, diabetic control, and diabetic training. The rats in diabetic training group were subjected to a resistance training program (3 days/wk, for 4 wk consisted of climbing a ladder carrying a load suspended from the tail. Following four weeks resistance training serum lipid profile, glucose, SAA and apoA-I concentrations were measured.Results: We did not find any significant difference in serum lipid profile between all groups. Serum levels of SAA and apoA-I were significantly higher in both diabetic groups compare with non-diabetic control group (respectively, P=0.020 & P= 0.001. After 4 weeks of resistance training serum apoA-I levels significantly increased compared with diabetic control group (P= 0.035, but we did not find any significant difference in SAA levels between diabetic groups.Conclusion: This study indicated that resistance training could increase serum apoA-I levels in diabetic rats without significant changes in lipid profile and SAA levels. These changes may mitigate the risk for atherosclerosis progression and its clinical consequences in diabetic conditions

Alireza Safarzade

2013-09-01

103

The Proteome Response to Amyloid Protein Expression In Vivo  

Science.gov (United States)

Protein misfolding disorders such as Alzheimer, Parkinson and transthyretin amyloidosis are characterized by the formation of protein amyloid deposits. Although the nature and location of the aggregated proteins varies between different diseases, they all share similar molecular pathways of protein unfolding, aggregation and amyloid deposition. Most effects of these proteins are likely to occur at the proteome level, a virtually unexplored reality. To investigate the effects of an amyloid protein expression on the cellular proteome, we created a yeast expression system using human transthyretin (TTR) as a model amyloidogenic protein. We used Saccharomyces cerevisiae, a living test tube, to express native TTR (non-amyloidogenic) and the amyloidogenic TTR variant L55P, the later forming aggregates when expressed in yeast. Differential proteome changes were quantitatively analyzed by 2D-differential in gel electrophoresis (2D-DIGE). We show that the expression of the amyloidogenic TTR-L55P causes a metabolic shift towards energy production, increased superoxide dismutase expression as well as of several molecular chaperones involved in protein refolding. Among these chaperones, members of the HSP70 family and the peptidyl-prolyl-cis-trans isomerase (PPIase) were identified. The latter is highly relevant considering that it was previously found to be a TTR interacting partner in the plasma of ATTR patients but not in healthy or asymptomatic subjects. The small ubiquitin-like modifier (SUMO) expression is also increased. Our findings suggest that refolding and degradation pathways are activated, causing an increased demand of energetic resources, thus the metabolic shift. Additionally, oxidative stress appears to be a consequence of the amyloidogenic process, posing an enhanced threat to cell survival.

Gomes, Ricardo A.; Franco, Catarina; Da Costa, Goncalo; Planchon, Sebastien; Renaut, Jenny; Ribeiro, Raquel M.; Pinto, Francisco; Silva, Marta Sousa; Coelho, Ana Varela; Freire, Ana Ponces; Cordeiro, Carlos

2012-01-01

104

Protein phosphorylation inhibits production of Alzheimer amyloid beta/A4 peptide.  

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The major component of amyloid plaque cores and cerebrovascular amyloid deposits found in Alzheimer disease is the beta/A4 peptide, which is derived from the Alzheimer amyloid protein precursor (APP). Recent evidence suggests that abnormalities in beta/A4 peptide production or beta/A4 peptide aggregation may underlie cerebral amyloidosis. In the present study, treatment of cells with phorbol dibutyrate, which activates protein kinase C, and/or okadaic acid, which inhibits protein phosphatases...

Buxbaum, J. D.; Koo, E. H.; Greengard, P.

1993-01-01

105

Protein Polymers and Amyloids : Focus on α1-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 Alzheimerâ??s and Parkinsonâ??s, where accumulation of protein fibrillar structures, known as amyloid fibrils, is a general hallmark. They also include the α1-antitrypsin deficiency, where disease-causing mutations in the serine protease inhibitor, α1-antitrypsin (α1AT), leads to accumulation of the aberrant protein in the liver of these patients. The native metastable structure of α1AT 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 α1AT 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 α1AT 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 α1AT and provided proof-of-concept for the strategy. The polymerization of α1AT 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 α1AT 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 α1AT that could be targeted to serve this purpose. The proteolytically generated C-terminal tail from α1AT 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 β-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 β-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 integr

Risør, Michael Wulff

2014-01-01

106

Expression of serum amyloid a in human ovarian epithelial tumors: implication for a role in ovarian tumorigenesis.  

Science.gov (United States)

Serum amyloid A (SAA) is an acute phase protein which is expressed primarily in the liver as a part of the systemic response to various injuries and inflammatory stimuli; its expression in ovarian tumors has not been described. Here, we investigated the expression of SAA in human benign and malignant ovarian epithelial tumors. Non-radioactive in situ hybridization applied on ovarian paraffin tissue sections revealed mostly negative SAA mRNA expression in normal surface epithelium. Expression was increased gradually as epithelial cells progressed through benign and borderline adenomas to primary and metastatic adenocarcinomas. Similar expression pattern of the SAA protein was observed by immunohistochemical staining. RT-PCR analysis confirmed the overexpression of the SAA1 and SAA4 genes in ovarian carcinomas compared with normal ovarian tissues. In addition, strong expression of SAA mRNA and protein was found in the ovarian carcinoma cell line OVCAR-3. Finally, patients with ovarian carcinoma had high SAA serum levels, which strongly correlated with high levels of CA-125 and C-reactive protein. Enhanced expression of SAA in ovarian carcinomas may play a role in ovarian tumorigenesis and may have therapeutic application. PMID:20713982

Urieli-Shoval, Simcha; Finci-Yeheskel, Zvezdana; Dishon, Shira; Galinsky, Daliah; Linke, Reinhold P; Ariel, Ilana; Levin, Mark; Ben-Shachar, Inbar; Prus, Diana

2010-11-01

107

Betaine suppressed A? generation by altering amyloid precursor protein processing.  

Science.gov (United States)

Betaine was an endogenous catabolite of choline, which could be isolated from vegetables and marine products. Betaine could promote the metabolism of homocysteine in healthy subjects and was used for hyperlipidemia, coronary atherosclerosis, and fatty liver in clinic. Recent findings shown that Betaine rescued neuronal damage due to homocysteine induced Alzheimer's disease (AD) like pathological cascade, including tau hyperphosphorylation and amyloid-? (A?) deposition. A? was derived from amyloid precursor protein (APP) processing, and was a triggering factor for AD pathological onset. Here, we demonstrated that Betaine reduced A? levels by altering APP processing in N2a cells stably expressing Swedish mutant of APP. Betaine increased ?-secretase activity, but decreased ?-secretase activity. Our data indicate that Betaine might play a protective role in A? production. PMID:24549986

Liu, Xiu-Ping; Qian, Xiang; Xie, Yue; Qi, Yan; Peng, Min-Feng; Zhan, Bi-Cui; Lou, Zheng-Qing

2014-07-01

108

In vitro Generation of Amyloid A4 Peptide from Amyloid Protein Precursor Through Nonspecific Proteolysis  

Directory of Open Access Journals (Sweden)

Full Text Available Amyloid A4 peptide, the principal constituents of the senile plaques in Alzheimer`s disease (AD originates from proteolysis of a larger protein precursor (APP. Several lines of evidence suggest that this peptide may be generated from aggregated precursor through nonspecific proteolysis. In this work, we used a sensitive in vitro method of detection to investigate the role of nonspecific proteases in the processing of a 100-amino acid C-terminal fragment (C100 inclusive of A4 and cytoplasmic domain of APP. We demonstrate first that C100 forms high molecular weight aggregates in vitro as determined by size exclusion chromatography. Digestion of aggregated C100 with the nonspecific enzyme, proteinase K resulted in cleavage at the amyloidogenic -secretase sites. This occurred at Ala 42-Val 43 generating A4 12-42 & A4 16-42 amyloid peptides. The enzyme cleaved most of the peptide bonds of the cytoplasmic domain and the upstream of A4 domain of the substrate. The result suggests that both the N- and C-terminus A4 can be generated by nonspecific proteases, acting on a aggregated substrate and support the notion that the A4 can be formed in organelles containing proteases capable of cleaving most peptide bonds.

Golam Sadik

2001-01-01

109

Amyloid ? precursor protein as a molecular target for amyloid ?--induced neuronal degeneration in Alzheimer's disease.  

Science.gov (United States)

A role of amyloid ? (A?) peptide aggregation and deposition in Alzheimer's disease (AD) pathogenesis is widely accepted. Significantly, abnormalities induced by aggregated A? have been linked to synaptic and neuritic degeneration, consistent with the "dying-back" pattern of degeneration that characterizes neurons affected in AD. However, molecular mechanisms underlying the toxic effect of aggregated A? remain elusive. In the last 2 decades, a variety of aggregated A? species have been identified and their toxic properties demonstrated in diverse experimental systems. Concurrently, specific A? assemblies have been shown to interact and misregulate a growing number of molecular effectors with diverse physiological functions. Such pleiotropic effects of aggregated A? posit a mayor challenge for the identification of the most cardinal A? effectors relevant to AD pathology. In this review, we discuss recent experimental evidence implicating amyloid ? precursor protein (APP) as a molecular target for toxic A? assemblies. Based on a significant body of pathologic observations and experimental evidence, we propose a novel pathologic feed-forward mechanism linking A? aggregation to abnormalities in APP processing and function, which in turn would trigger the progressive loss of neuronal connectivity observed early in AD. PMID:23714735

Bignante, Elena Anahi; Heredia, Florencia; Morfini, Gerardo; Lorenzo, Alfredo

2013-11-01

110

Structural and Functional Alterations in Amyloid-? Precursor Protein Induced by Amyloid-? Peptides  

Science.gov (United States)

Alzheimer's disease-associated amyloid-? (A?) peptide is neurotoxic as an oligomer, but not as a monomer, by an unknown mechanism. We showed previously that A? interacts with the amyloid-? precursor protein (A?PP), leading to caspase cleavage and cell death induction. To characterize this structure and interaction further, we purified the extracellular domain of A?PP695 (eA?PP) and its complex with A? oligomers (A?Os) of varying sizes, and then performed small angle X-ray scattering (SAXS). In the absence of any A?, eA?PP was a compact homodimer with a tight association between the E1 and E2 domains. Dimeric A? oligomers induced monomerization of eA?PP while larger oligomers also bound eA?PP but preserved the homodimer. Efficient binding of the larger oligomers correlated with the presence of prefibrillar oligomers, suggesting that the eA?PP binding is limited to a conformational subset of A? oligomers. Both forms of A? bound to eA?PP at the A?-cognate region and induced dissociation of the E1 and E2 domains. Our data provide the first structural evidence for A?-A?PP binding and suggest a mechanism for differential modulation of A?PP processing and cell death signaling by A? dimers versus conformationally-specific larger oligomers.

Libeu, Clare Peters; Poksay, Karen S.; John, Varghese; Bredesen, Dale E.

2014-01-01

111

Membrane mediated aggregation of amyloid-? protein : a potential key event in Alzheimer's disease  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The pathogenesis of Alzheimer’s disease (AD), the most common senile dementia, is a complex process. A crucial event in AD is the aggregation of amyloid-? protein (A?), a cleavage product from the Amyloid Precursor Protein (APP). A?40, a common component in amyloid plaques found in patients, aggregates in vitro at concentrations, much higher than the one found in vivo. But in the presence of charged lipid membranes, aggregations occurs at much lower concentration in vitro compared to the...

Bokvist, Marcus

2007-01-01

112

Serum amyloid a is associated with obesity and estrogen receptor-negative tumors in postmenopausal women with breast cancer.  

Science.gov (United States)

Serum amyloid A (SAA) is an acute-phase protein and also an adipokine, which has been associated with the development and prognosis of breast cancer. In the present study, we investigated the association between obesity and SAA in postmenopausal women with breast cancer and its relationship with clinicopathologic characteristics of tumors. Patients were grouped as nonobese or overweight/obese based on body mass index (BMI) plus waist circumference measurement. Serum SAA concentrations were determined by high-sensitivity micro-latex agglutination tests, detected by nephelometry. Serum SAA concentrations were higher in overweight/obese (P = 0.008) patients and this condition was dependent on obesity (BMI and waist circumference), as further shown by multivariate linear regression analysis done for SAA (P = 0.01). Concentrations of SAA were also higher in patients with estrogen receptor-negative (ER(-)) tumors than in those with estrogen receptor-positive (ER(+); P = 0.033). Our results suggest a possible role for SAA in the development and prognosis of obesity-related breast cancer. A follow-up study of this population to assess overall and disease-free survival is in course and should bring contribution to evaluate the clinical role of SAA in breast cancer in the context of obesity. PMID:23300020

Santana, Aline Barros; Gurgel, Maria Salete Costa; de Oliveira Montanari, Joelma Ferreira; Bonini, Flavia Muraro; de Barros-Mazon, Silvia

2013-02-01

113

Ichthyophthirius multifiliis infection induces massive up-regulation of serum amyloid A in carp (Cyprinus carpio)  

DEFF Research Database (Denmark)

A real time quantitative PCR (RQ-PCR) assay was developed for measurement of differential expression of the genes encoding the acute phase reactant serum amyloid A (SAA), transferrin (TF) and a C-type lectin molecule (CL) in skin, blood and liver from Cyprinus carpio following infection with the ectoparasite Ichthyophthirius multifiliis. Serum amyloid A and CL were constitutively expressed in all organs evaluated while TF transcripts were only detected in the liver. A dramatic up-regulation (1600 times) in the expression levels of SAA was observed in skin 36 h after the parasite infection. A similar increase in the number of RNA molecules encoding for SAA was observed in the liver. The CL expression was significantly down regulated in all the organs and no significant change was observed in the expression levels of the TF in the liver. These results indicate that SAA plays a major role in the acute phase response in fish infected with I. multififiis and emphasize the importance of the fish skin as an active organ in response to an ectoparasite infection. (c) 2006 Elsevier B.V. All rights reserved.

Gonzales, S.F.; Buchmann, Kurt

2007-01-01

114

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

115

Structural dynamics of the amyloid ?-protein monomer folding nucleus  

Science.gov (United States)

Alzheimer's disease (AD) is linked to the aberrant assembly of the amyloid ?-protein (A?). The 21AEDVGSNKGA30 segment, A?(21-30), forms a turn that acts as a monomer folding nucleus. Amino acid substitutions within this nucleus cause familial forms of AD. To determine the biophysical characteristics of the folding nucleus, we studied the biologically relevant acetyl-A?(21-30)-amide peptide using experimental techniques (limited proteolysis, thermal denaturation, urea denaturation followed by pulse proteolysis, electron microscopy) and computational methods (molecular dynamics). Our results reveal a highly stable foldon and suggest new strategies for therapeutic drug development.

Roychaudhuri, Robin; Yang, Mingfeng; Condron, Margaret M.; Teplow, David B.

2012-01-01

116

Structural dynamics of the amyloid ?-protein monomer folding nucleus.  

Science.gov (United States)

Alzheimer's disease (AD) is linked to the aberrant assembly of the amyloid ?-protein (A?). The (21)AEDVGSNKGA(30) segment, A?(21-30), forms a turn that acts as a monomer folding nucleus. Amino acid substitutions within this nucleus cause familial forms of AD. To determine the biophysical characteristics of the folding nucleus, we studied the biologically relevant acetyl-A?(21-30)-amide peptide using experimental techniques (limited proteolysis, thermal denaturation, urea denaturation followed by pulse proteolysis, and electron microscopy) and computational methods (molecular dynamics). Our results reveal a highly stable foldon and suggest new strategies for therapeutic drug development. PMID:22551351

Roychaudhuri, Robin; Yang, Mingfeng; Condron, Margaret M; Teplow, David B

2012-05-15

117

Mechanisms of prion protein assembly into amyloid  

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The conversion of the ?-helical, cellular isoform of the prion protein (PrPC) to the insoluble, ?-sheet-rich, infectious, disease-causing isoform (PrPSc) is the key event in prion diseases. In an earlier study, several forms of PrP were converted into a fibrillar state by using an in vitro conversion system consisting of low concentrations of SDS and 250 mM NaCl. Here, we characterize the structure of the fibril precursor state, that is, the soluble state under fibrillization conditions. CD...

Sto?hr, Jan; Weinmann, Nicole; Wille, Holger; Kaimann, Tina; Nagel-steger, Luitgard; Birkmann, Eva; Panza, Giannantonio; Prusiner, Stanley B.; Eigen, Manfred; Riesner, Detlev

2008-01-01

118

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 SciELO Chile | Language: Spanish Abstract in spanish 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.

119

Novel neuritic clusters with accumulations of amyloid precursor protein and amyloid precursor-like protein 2 immunoreactivity in brain regions damaged by thiamine deficiency.  

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Experimental thiamine deficiency (TD) is a classical model of a nutritional deficit associated with a generalized impairment of oxidative metabolism and selective cell loss in the brain. In rats, TD-induced cell degeneration is accompanied by an accumulation of amyloid precursor protein (APP)/amyloid precursor-like protein 2 (APLP2) immunoreactivity in abnormal neurites and perikarya along the periphery of, or scattered within, the lesion. Prompted by these data and our previous findings of a...

Calingasan, N. Y.; Gandy, S. E.; Baker, H.; Sheu, K. F.; Smith, J. D.; Lamb, B. T.; Gearhart, J. D.; Buxbaum, J. D.; Harper, C.; Selkoe, D. J.; Price, D. L.; Sisodia, S. S.; Gibson, G. E.

1996-01-01

120

Lower serum uric acid levels in cerebral amyloid angiopathy: a pilot study.  

Science.gov (United States)

Cerebral amyloid angiopathy (CAA) is a common degenerative disease presenting intracerebral hemorrhage (ICH) in older people. Uric acid (UA) is a natural antioxidant, and may have a beneficial role in neurodegenerative diseases. Nevertheless, the role of UA in CAA remains unknown. In the present study, we compared serum UA levels in CAA-associated ICH patients (n = 82) and age/sex-matched controls (n = 82). Serum UA levels in possible CAA were significantly decreased when compared with healthy controls (232.68 ± 77.70 vs. 309.42 ± 59.83 ?mol/L; p < 0.001). Furthermore, UA levels in patients clinically diagnosed as probable CAA were significantly lower than those in patients diagnosed as possible CAA (193.06 ± 56.98 vs. 232.68 ± 77.70 ?mol/L; p = 0.014). These differences were still significant after adjusting for renal function and dyslipidemia (p < 0.001 and p = 0.002, respectively). However, there were no associations between serum UA levels and the distribution of hemorrhagic lesion, as well as neurological impairment. Our observations indicate that serum UA levels were decreased in CAA patients. UA might play a neuroprotective role in CAA and serve as a potential biomarker for reflecting the severity of A? deposition. PMID:24464503

Hu, Qi; Liu, Anding; Huang, Mengyang; Cheng, Luo; Kang, Huicong; Xu, Feng; Liu, Xiaoyan; Lian, Lifei; Liang, Qiming; Jiang, Hong; Zhang, Cuntai; Zhu, Suiqiang

2014-07-01

 
 
 
 
121

Mechanisms of prion protein assembly into amyloid.  

Science.gov (United States)

The conversion of the alpha-helical, cellular isoform of the prion protein (PrP(C)) to the insoluble, beta-sheet-rich, infectious, disease-causing isoform (PrP(Sc)) is the key event in prion diseases. In an earlier study, several forms of PrP were converted into a fibrillar state by using an in vitro conversion system consisting of low concentrations of SDS and 250 mM NaCl. Here, we characterize the structure of the fibril precursor state, that is, the soluble state under fibrillization conditions. CD spectroscopy, analytical ultracentrifugation, and chemical cross-linking indicate that the precursor state exists in a monomer-dimer equilibrium of partially denatured, alpha-helical PrP, with a well defined contact site of the subunits in the dimer. Using fluorescence with thioflavin T, we monitored and quantitatively described the kinetics of seeded fibril formation, including dependence of the reaction on substrate and seed concentrations. Exponential, seed-enhanced growth can be achieved in homogeneous solution, which can be enhanced by sonication. From these data, we propose a mechanistic model of fibrillization, including the presence of several intermediate structures. These studies also provide a simplified amplification system for prions. PMID:18268326

Stöhr, Jan; Weinmann, Nicole; Wille, Holger; Kaimann, Tina; Nagel-Steger, Luitgard; Birkmann, Eva; Panza, Giannantonio; Prusiner, Stanley B; Eigen, Manfred; Riesner, Detlev

2008-02-19

122

Comparable dimerization found in wildtype and familial Alzheimer’s disease amyloid precursor protein mutants  

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Alzheimer’s disease (AD) is a progressive and fatal neurodegenerative disorder marked by memory impairment and cognitive deficits. A major component of AD pathology is the accumulation of amyloid plaques in the brain, which are comprised of amyloid beta (A?) peptides derived from the amyloidogenic processing of the amyloid precursor protein (A?PP) by ?- and ?-secretases. In a subset of patients, inheritance of mutations in the A?PP gene is responsible for altering A? production, leadi...

So, Pauline Pl; Khodr, Christina E.; Chen, Ci-di; Abraham, Carmela R.

2013-01-01

123

Heparan sulfate regulates amyloid precursor protein processing by BACE1, the Alzheimer's ?-secretase  

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Cleavage of amyloid precursor protein (APP) by the Alzheimer's ?-secretase (BACE1) is a key step in generating amyloid ?-peptide, the main component of amyloid plaques. Here we report evidence that heparan sulfate (HS) interacts with ?-site APP-cleaving enzyme (BACE) 1 and regulates its cleavage of APP. We show that HS and heparin interact directly with BACE1 and inhibit in vitro processing of peptide and APP substrates. Inhibitory activity is dependent on saccharide size and specific stru...

2003-01-01

124

Structural and Dynamic Study of the Transmembrane Domain of the Amyloid Precursor Protein  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Alzheimer’s disease affects people all over the world, regardless of nationality, gender or social status. An adequate study of the disease requires essential understanding of the molecular fundamentals of the pathogenesis. The amyloid ?-peptide, which forms amyloid plaques in the brain of people with Alzheimer’s disease, is the product of sequential cleavage of a single-span membrane amyloid precursor protein (APP). More than half of the APP mutations found to be associated with familia...

Nadezhdin, K. D.; Bocharova, O. V.; Bocharov, E. V.; Arseniev, A. S.

2011-01-01

125

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

International Nuclear Information System (INIS)

The authors have isolated genomic and cDNA clones for a Drosophila gene resembling the human ?-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 ?-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

1989-01-01

126

Expression of serum amyloid A, in normal, dysplastic, and neoplastic human colonic mucosa: implication for a role in colonic tumorigenesis.  

Science.gov (United States)

Serum amyloid A (SAA) is an acute phase reactant, whose level in the blood is elevated in response to trauma, infection, inflammation, and neoplasia. Elevated levels of SAA in the serum of cancer patients were suggested to be of liver origin rather than a tumor cell product. The role of SAA in human malignancies has not been elucidated. We investigated the expression of SAA at various stages of human colon carcinoma progression. Nonradioactive in situ hybridization applied on paraffin tissue sections from 26 colon cancer patients revealed barely detected SAA mRNA expression in normal looking colonic epithelium. Expression was increased gradually as epithelial cells progressed through dysplasia to neoplasia. Deeply invading colon carcinoma cells showed the highest levels of SAA. Expression was also found in colon carcinoma metastases. Cells of lymphoid follicles of the intestinal wall, inflammatory cells, ganglion cells, and endothelial cells, also expressed SAA mRNA. Immunohistochemical staining revealed SAA protein expression that colocalized with SAA mRNA expression. RT-PCR analysis confirmed the expression of the SAA1 and SAA4 genes in colon carcinomas, expression that was barely detectable in normal colon tissues. These findings indicate local and differential expression of SAA in human colon cancer tissues and suggest its role in colonic tumorigenesis. PMID:16116035

Gutfeld, Orit; Prus, Diana; Ackerman, Zvi; Dishon, Shira; Linke, Reinhold P; Levin, Mark; Urieli-Shoval, Simcha

2006-01-01

127

Endogenous Acute Phase Serum Amyloid A Lacks Pro-Inflammatory Activity, Contrasting the Two Recombinant Variants That Activate Human Neutrophils through Different Receptors  

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Most notable among the acute phase proteins is serum amyloid A (SAA), levels of which can increase 1000-fold during infections, aseptic inflammation, and/or trauma. Chronically elevated SAA levels are associated with a wide variety of pathological conditions, including obesity and rheumatic diseases. Using a recombinant hybrid of the two human SAA isoforms (SAA1 and 2) that does not exist in vivo, numerous in vitro studies have given rise to the notion that acute phase SAA is a pro-inflammato...

Christenson, Karin; Bjo?rkman, Lena; Ahlin, Sofie; Olsson, Maja; Sjo?holm, Kajsa; Karlsson, Anna; Bylund, Johan

2013-01-01

128

Formation of amphipathic amyloid monolayers from fungal hydrophobin proteins.  

Science.gov (United States)

The fungal hydrophobins are small proteins that are able to spontaneously self-assemble into amphipathic monolayers at hydrophobic:hydrophilic interfaces. These protein monolayers can reverse the wettability of a surface, making them suitable for increasing the biocompatibility of many hydrophobic nanomaterials. One subgroup of this family, the class I hydrophobins, forms monolayers that are composed of extremely robust amyloid-like fibrils, called rodlets. Here we describe protocols for the production and purification of recombinant hydrophobins and oxidative refolding to a biologically active, soluble, monomeric form. We describe methods to trigger self-assembly into the fibrillar rodlet state and techniques to characterize the physicochemical properties of the polymeric forms. PMID:23504421

Morris, Vanessa K; Sunde, Margaret

2013-01-01

129

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

130

High molecular mass assemblies of amyloid-? oligomers bind prion protein in patients with Alzheimer's disease.  

Science.gov (United States)

Alzheimer's disease is the most common form of dementia and the generation of oligomeric species of amyloid-? is causal to the initiation and progression of it. Amyloid-? oligomers bind to the N-terminus of plasma membrane-bound cellular prion protein (PrP(C)) initiating a series of events leading to synaptic degeneration. Composition of bound amyloid-? oligomers, binding regions within PrP(C), binding affinities and modifiers of this interaction have been almost exclusively studied in cell culture or murine models of Alzheimer's disease and our knowledge on PrP(C)-amyloid-? interaction in patients with Alzheimer's disease is limited regarding occurrence, binding regions in PrP(C), and size of bound amyloid-? oligomers. Here we employed a PrP(C)-amyloid-? binding assay and size exclusion chromatography on neuropathologically characterized Alzheimer's disease and non-demented control brains (n = 15, seven female, eight male, average age: 79.2 years for Alzheimer's disease and n = 10, three female, seven male, average age: 66.4 years for controls) to investigate amyloid-?-PrP(C) interaction. PrP(C)-amyloid-? binding always occurred in Alzheimer's disease brains and was never detected in non-demented controls. Neither expression level of PrP(C) nor known genetic modifiers of Alzheimer's disease, such as the PrP(C) codon 129 polymorphism, influenced this interaction. In Alzheimer's disease brains, binding of amyloid-? to PrP(C) occurred via the PrP(C) N-terminus. For synthetic amyloid-?42, small oligomeric species showed prominent binding to PrP(C), whereas in Alzheimer's disease brains larger protein assemblies containing amyloid-?42 bound efficiently to PrP(C). These data confirm Alzheimer's disease specificity of binding of amyloid-? to PrP(C) via its N-terminus in a large cohort of Alzheimer's disease/control brains. Differences in sizes of separated protein fractions between synthetic and brain-derived amyloid-? binding to PrP(C) suggest that larger assemblies of amyloid-? or additional non-amyloid-? components may play a role in binding of amyloid-?42 to PrP(C) in Alzheimer's disease. PMID:24519981

Dohler, Frank; Sepulveda-Falla, Diego; Krasemann, Susanne; Altmeppen, Hermann; Schlüter, Hartmut; Hildebrand, Diana; Zerr, Inga; Matschke, Jakob; Glatzel, Markus

2014-03-01

131

Supramolecular organization of protein-releasing functional amyloids solved in bacterial inclusion bodies.  

Science.gov (United States)

Slow protein release from amyloidal materials is a molecular platform used by nature to control protein hormone secretion in the endocrine system. The molecular mechanics of the sustained protein release from amyloids remains essentially unexplored. Inclusion bodies (IBs) are natural amyloids that occur as discrete protein nanoparticles in recombinant bacteria. These protein clusters have been recently explored as protein-based functional biomaterials with diverse biomedical applications, and adapted as nanopills to deliver recombinant protein drugs into mammalian cells. Interestingly, the slow protein release from IBs does not significantly affect the particulate organization and morphology of the material, suggesting the occurrence of a tight scaffold. Here, we have determined, by using a combined set of analytical approaches, a sponge-like supramolecular organization of IBs combining differently folded protein versions (amyloid and native-like), which supports both mechanical stability and sustained protein delivery. Apart from offering structural clues about how amyloid materials release their monomeric protein components, these findings open exciting possibilities for the tailored development of smart biofunctional materials, adapted to mimic the functions of amyloid-based secretory glands of higher organisms. PMID:23220450

Cano-Garrido, Olivia; Rodríguez-Carmona, Escarlata; Díez-Gil, César; Vázquez, Esther; Elizondo, Elisa; Cubarsi, Rafael; Seras-Franzoso, Joaquin; Corchero, José Luis; Rinas, Ursula; Ratera, Imma; Ventosa, Nora; Veciana, Jaume; Villaverde, Antonio; García-Fruitós, Elena

2013-04-01

132

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2013-01-01

133

Structure-neurotoxicity relationships of amyloid ?-protein oligomers  

Science.gov (United States)

Amyloid ?-protein (A?) oligomers may be the proximate neurotoxins in Alzheimer's disease (AD). “Oligomer” is an ill-defined term because many kinds have been reported and they often exist in rapid equilibrium with monomers and higher-order assemblies. We report here results of studies in which specific oligomers have been stabilized structurally, fractionated in pure form, and then studied by using a combination of CD spectroscopy, Thioflavin T fluorescence, EM, atomic force microscopy (AFM), and neurotoxicity assays. A? monomers were largely unstructured, but oligomers exhibited order-dependent increases in ?-sheet content. EM and AFM data suggest that dimerization and subsequent monomer addition are processes in which significant and asymmetric monomer conformational changes occur. Oligomer secondary structure and order correlated directly with fibril nucleation activity. Neurotoxic activity increased disproportionately (order dependence >1) with oligomer order. The structure–activity correlations reported here significantly extend our understanding of the conformational dynamics, structure, and relative toxicity of pure A? oligomers of specific order.

Ono, Kenjiro; Condron, Margaret M.; Teplow, David B.

2009-01-01

134

Ultrasonication: An Efficient Agitation for Accelerating the Supersaturation-Limited Amyloid Fibrillation of Proteins  

Science.gov (United States)

Amyloid fibrils are self-assemblies of proteins with an ordered cross-? architecture. Because they are associated with serious disorders, understanding their structure and mechanism of fibrillation is important. Irradiation with ultrasonication leads to fragmentation of amyloid fibrils, useful for seeding experiments. Recently, ultrasonication has been found to trigger the spontaneous formation of fibrils in solutions of monomeric amyloidogenic proteins. The results indicate that amyloid fibrillation is similar to the crystallization of solutes from a supersaturated solution. The accelerating effects of ultrasonication on amyloid fibrillation suggest that cavitation microbubbles play a key role in effectively converting the metastable state of supersaturation to the labile state, leading to spontaneous fibrillation. Moreover, ultrasonic irradiation would be promising for a high-throughput screening assay of amyloid fibrillation, advancing the study of supersaturation-limited amyloidogenesis.

Yoshimura, Yuichi; So, Masatomo; Yagi, Hisashi; Goto, Yuji

2013-07-01

135

Adenosine Triphosphate (ATP) Reduces Amyloid-? Protein Misfolding in vitro.  

Science.gov (United States)

Alzheimer's disease (AD) is a devastating disease of aging that initiates decades prior to clinical manifestation and represents an impending epidemic. Two early features of AD are metabolic dysfunction and changes in amyloid-? protein (A?) levels. Since levels of ATP decrease over the course of the disease and A? is an early biomarker of AD, we sought to uncover novel linkages between the two. First and remarkably, a GxxxG motif is common between both A? (oligomerization motif) and nucleotide binding proteins (Rossmann fold). Second, ATP was demonstrated to protect against A? mediated cytotoxicity. Last, there is structural similarity between ATP and amyloid binding/inhibitory compounds such as ThioT, melatonin, and indoles. Thus, we investigated whether ATP alters misfolding of the pathologically relevant A?42. To test this hypothesis, we performed computational and biochemical studies. Our computational studies demonstrate that ATP interacts strongly with Tyr10 and Ser26 of A? fibrils in solution. Experimentally, both ATP and ADP reduced A? misfolding at physiological intracellular concentrations, with thresholds at ~500 ?M and 1 mM respectively. This inhibition of A? misfolding is specific; requiring Tyr10 of A? and is enhanced by magnesium. Last, cerebrospinal fluid ATP levels are in the nanomolar range and decreased with AD pathology. This initial and novel finding regarding the ATP interaction with A? and reduction of A? misfolding has potential significance to the AD field. It provides an underlying mechanism for published links between metabolic dysfunction and AD. It also suggests a potential role of ATP in AD pathology, as the occurrence of misfolded extracellular A? mirrors lowered extracellular ATP levels. Last, the findings suggest that A? conformation change may be a sensor of metabolic dysfunction. PMID:24625803

Coskuner, Orkid; Murray, Ian V J

2014-01-01

136

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

137

Selective Translational Control of the Alzheimer Amyloid Precursor Protein Transcript by Iron Regulatory Protein-1*?  

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Iron influx increases the translation of the Alzheimer amyloid precursor protein (APP) via an iron-responsive element (IRE) RNA stem loop in its 5?-untranslated region. Equal modulated interaction of the iron regulatory proteins (IRP1 and IRP2) with canonical IREs controls iron-dependent translation of the ferritin subunits. However, our immunoprecipitation RT-PCR and RNA binding experiments demonstrated that IRP1, but not IRP2, selectively bound the APP IRE in human neural cells. This sele...

2010-01-01

138

On the nucleation of amyloid beta-protein monomer folding.  

Science.gov (United States)

Neurotoxic assemblies of the amyloid beta-protein (Abeta) have been linked strongly to the pathogenesis of Alzheimer's disease (AD). Here, we sought to monitor the earliest step in Abeta assembly, the creation of a folding nucleus, from which oligomeric and fibrillar assemblies emanate. To do so, limited proteolysis/mass spectrometry was used to identify protease-resistant segments within monomeric Abeta(1-40) and Abeta(1-42). The results revealed a 10-residue, protease-resistant segment, Ala21-Ala30, in both peptides. Remarkably, the homologous decapeptide, Abeta(21-30), displayed identical protease resistance, making it amenable to detailed structural study using solution-state NMR. Structure calculations revealed a turn formed by residues Val24-Lys28. Three factors contribute to the stability of the turn, the intrinsic propensities of the Val-Gly-Ser-Asn and Gly-Ser-Asn-Lys sequences to form a beta-turn, long-range Coulombic interactions between Lys28 and either Glu22 or Asp23, and hydrophobic interaction between the isopropyl and butyl side chains of Val24 and Lys28, respectively. We postulate that turn formation within the Val24-Lys28 region of Abeta nucleates the intramolecular folding of Abeta monomer, and from this step, subsequent assembly proceeds. This model provides a mechanistic basis for the pathologic effects of amino acid substitutions at Glu22 and Asp23 that are linked to familial forms of AD or cerebral amyloid angiopathy. Our studies also revealed that common C-terminal peptide segments within Abeta(1-40) and Abeta(1-42) have distinct structures, an observation of relevance for understanding the strong disease association of increased Abeta(1-42) production. Our results suggest that therapeutic approaches targeting the Val24-Lys28 turn or the Abeta(1-42)-specific C-terminal fold may hold promise. PMID:15930005

Lazo, Noel D; Grant, Marianne A; Condron, Margaret C; Rigby, Alan C; Teplow, David B

2005-06-01

139

On the nucleation of amyloid ?-protein monomer folding  

Science.gov (United States)

Neurotoxic assemblies of the amyloid ?-protein (A?) have been linked strongly to the pathogenesis of Alzheimer’s disease (AD). Here, we sought to monitor the earliest step in A? assembly, the creation of a folding nucleus, from which oligomeric and fibrillar assemblies emanate. To do so, limited proteolysis/mass spectrometry was used to identify protease-resistant segments within monomeric A?(1–40) and A?(1–42). The results revealed a 10-residue, protease-resistant segment, Ala21–Ala30, in both peptides. Remarkably, the homologous decapeptide, A?(21–30), displayed identical protease resistance, making it amenable to detailed structural study using solution-state NMR. Structure calculations revealed a turn formed by residues Val24–Lys28. Three factors contribute to the stability of the turn, the intrinsic propensities of the Val-Gly-Ser-Asn and Gly-Ser-Asn-Lys sequences to form a ?-turn, long-range Coulombic interactions between Lys28 and either Glu22 or Asp23, and hydrophobic interaction between the isopropyl and butyl side chains of Val24 and Lys28, respectively. We postulate that turn formation within the Val24–Lys28 region of A? nucleates the intramolecular folding of A? monomer, and from this step, subsequent assembly proceeds. This model provides a mechanistic basis for the pathologic effects of amino acid substitutions at Glu22 and Asp23 that are linked to familial forms of AD or cerebral amyloid angiopathy. Our studies also revealed that common C-terminal peptide segments within A?(1–40) and A?(1–42) have distinct structures, an observation of relevance for understanding the strong disease association of increased A?(1–42) production. Our results suggest that therapeutic approaches targeting the Val24–Lys28 turn or the A?(1–42)-specific C-terminal fold may hold promise.

Lazo, Noel D.; Grant, Marianne A.; Condron, Margaret C.; Rigby, Alan C.; Teplow, David B.

2005-01-01

140

Enhanced fluorescent assignment of protein aggregates by an oligothiophene-porphyrin-based amyloid ligand.  

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Fluorescent probes identifying protein aggregates are of great interest, as deposition of aggregated proteins is associated with many devastating diseases. Here, we report that a fluorescent amyloid ligand composed of two distinct molecular moieties, an amyloidophilic pentameric oligothiophene and a porphyrin, can be utilized for spectral and lifetime imaging assessment of recombinant A? 1-42 amyloid fibrils and A? deposits in brain tissue sections from a transgenic mouse model with Alzheimer's disease pathology. The enhanced spectral range and distinct lifetime diversity of this novel oligothiophene-porphyrin-based ligand allow a more precise assessment of heterogeneous amyloid morphology compared with the corresponding oligothiophene dye. PMID:23468206

Arja, Katriann; Sjölander, Daniel; Åslund, Alma; Prokop, Stefan; Heppner, Frank L; Konradsson, Peter; Lindgren, Mikael; Hammarström, Per; Åslund, K O Andreas; Nilsson, K Peter R

2013-05-14

 
 
 
 
141

Elongation of Mouse Prion Protein Amyloid-Like Fibrils: Effect of Temperature and Denaturant Concentration  

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Prion protein is known to have the ability to adopt a pathogenic conformation, which seems to be the basis for protein-only infectivity. The infectivity is based on self-replication of this pathogenic prion structure. One of possible mechanisms for such replication is the elongation of amyloid-like fibrils. We measured elongation kinetics and thermodynamics of mouse prion amyloid-like fibrils at different guanidine hydrochloride (GuHCl) concentrations. Our data show that both increases in temperature and GuHCl concentration help unfold monomeric protein and thus accelerate elongation. Once the monomers are unfolded, further increases in temperature raise the rate of elongation, whereas the addition of GuHCl decreases it. We demonstrated a possible way to determine different activation energies of amyloid-like fibril elongation by using folded and unfolded protein molecules. This approach separates thermodynamic data for fibril-assisted monomer unfolding and for refolding and formation of amyloid-like structure.

Milto, Katazyna; Michailova, Ksenija; Smirnovas, Vytautas

2014-01-01

142

Amyloid precursor proteins are constituents of the presynaptic active zone.  

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The amyloid precursor protein (APP) and its mammalian homologs, APLP1, APLP2, have been allocated to an organellar pool residing in the Golgi apparatus and in endosomal compartments, and in its mature form to a cell surface-localized pool. In the brain, all APPs are restricted to neurons; however, their precise localization at the plasma membrane remained enigmatic. Employing a variety of subcellular fractionation steps, we isolated two synaptic vesicle (SV) pools from rat and mouse brain, a pool consisting of synaptic vesicles only and a pool comprising SV docked to the presynaptic plasma membrane. Immunopurification of these two pools using a monoclonal antibody directed against the 12 membrane span synaptic vesicle protein2 (SV2) demonstrated unambiguously that APP, APLP1 and APLP2 are constituents of the active zone of murine brain but essentially absent from free synaptic vesicles. The specificity of immunodetection was confirmed by analyzing the respective knock-out animals. The fractionation experiments further revealed that APP is accumulated in the fraction containing docked synaptic vesicles. These data present novel insights into the subsynaptic localization of APPs and are a prerequisite for unraveling the physiological role of all mature APP proteins in synaptic physiology. PMID:23815291

Laßek, Melanie; Weingarten, Jens; Einsfelder, Ulf; Brendel, Peter; Müller, Ulrike; Volknandt, Walter

2013-10-01

143

The Role of Phospholipase D in Amyloid Precursor Protein Processing  

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Full Text Available The generation of a secreted N-terminal fragment of the amyloid precursor protein (A PPs can be stimulated by a variety of signaling pathways many of which are also known to modulate the activity of the phospholipase D (PLD enzyme. This study used primary rat neuronal cerebellar granule (CG cultures and SH-SY5Y human neuroblastoma cell lines to determine the potential role of PLD in the protein kinase C (PKC-associated generation of A PPs. Protein release was markedly enhanced by direct PKC stimulation following treatment of both cell type with either phorbol ester or indirectly by the muscarinic agonist carbachol and these effects were greatly attenuated by co-incubation with the PKC inhibitor GF109203X. A partial inhibition of PKC- and carbachol-stimulated A PPs secretion was also achieved by pre-treatment of the cells with toxin B, a PLD inhibitor. This suggested that PLD may play a role downstream of PKC in the control of A PPs secretion.

Mark McLaughlin

2005-01-01

144

Amyloid precursor protein and tau transgenic models of Alzheimer's disease: insights from the past and directions for the future  

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During the last 20 years, our understanding of the mechanisms underlying Alzheimer's disease (AD) has considerably improved, in part owing to both in vitro and in vivo model systems. Studies in mice expressing both human amyloid precursor protein and human tau have provided clear evidence that amyloid-? and tau interact in the pathogenesis of AD. Moreover, amyloid-? toxicity has been shown to be tau-dependent since reducing tau levels prevents behavioral deficits and sudden death in amyloid...

Sahara, Naruhiko; Lewis, Jada

2010-01-01

145

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

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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

146

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

147

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

148

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

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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

149

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

150

Serum amyloid A induces mitogenic signals in regulatory T cells via monocyte activation.  

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Serum amyloid A (SAA) has recently been identified by our group as a mitogen for regulatory T cells (Treg). However, the molecular mechanism by which SAA induces Treg proliferation is unknown. Here we provide evidence that IL-1? and IL-6 are directly involved in the SAA-mediated proliferation of Treg. By engaging its several cognate receptors, SAA induces IL-1? and IL-6 secretion by monocytes and drives them toward an HLA-DR(hi) HVEM(lo) phenotype resembling immature dendritic cells, which have been implicated in tolerance generation. This monocyte-derived cytokine milieu is required for Treg expansion, as inhibition of IL-1? and IL-6 abrogate the ability of SAA to induce Treg proliferation. Furthermore, both IL-1? and IL-6 are required for ERK1/2 and AKT signaling in proliferating Treg. Collectively, these results point to a novel mechanism, by which SAA initiates a monocyte-dependent process that drives mitogenic signals in Treg. PMID:24632292

Nguyen, Khoa D; Macaubas, Claudia; Truong, Phi; Wang, Nan; Hou, Tieying; Yoon, Taejin; Mellins, Elizabeth D

2014-06-01

151

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

152

Proteins that bind to the RERMS region of ? amyloid precursor protein  

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The main objective of this study was to investigate the biological function of ? amyloid precursor protein (APP), in particular its nerve growth factor-like activity. We hypothesize that the extracellular domain containing the sequence RERMS, amino acids 328-332 of APP695, represents the active site for this function. Binding assays using peptide fragments of this domain have demonstrated specific and saturable binding to the cell surface with affinity in the low nanomolar range. This induce...

Pawlik, Monika; Otero, Deborah A. C.; Park, Minkyu; Fischer, Wolfgang H.; Levy, Efrat; Saitoh, Tsunao

2007-01-01

153

Ubiquilin 1 modulates amyloid precursor protein trafficking and Abeta secretion.  

Science.gov (United States)

Ubiquilin 1 (UBQLN1) is a ubiquitin-like protein, which has been shown to play a central role in regulating the proteasomal degradation of various proteins, including the presenilins. We recently reported that DNA variants in UBQLN1 increase the risk for Alzheimer disease, by influencing expression of this gene in brain. Here we present the first assessment of the effects of UBQLN1 on the metabolism of the amyloid precursor protein (APP). For this purpose, we employed RNA interference to down-regulate UBQLN1 in a variety of neuronal and non-neuronal cell lines. We demonstrate that down-regulation of UBQLN1 accelerates the maturation and intracellular trafficking of APP, while not interfering with alpha-, beta-, or gamma-secretase levels or activity. UBQLN1 knockdown increased the ratio of APP mature/immature, increased levels of full-length APP on the cell surface, and enhanced the secretion of sAPP (alpha- and beta-forms). Moreover, UBQLN1 knockdown increased levels of secreted Abeta40 and Abeta42. Finally, employing a fluorescence resonance energy transfer-based assay, we show that UBQLN1 and APP come into close proximity in intact cells, independently of the presence of the presenilins. Collectively, our findings suggest that UBQLN1 may normally serve as a cytoplasmic "gatekeeper" that may control APP trafficking from intracellular compartments to the cell surface. These findings suggest that changes in UBQLN1 steady-state levels affect APP trafficking and processing, thereby influencing the generation of Abeta. PMID:16945923

Hiltunen, Mikko; Lu, Alice; Thomas, Anne V; Romano, Donna M; Kim, Minji; Jones, Phill B; Xie, Zhongcong; Kounnas, Maria Z; Wagner, Steven L; Berezovska, Oksana; Hyman, Bradley T; Tesco, Giuseppina; Bertram, Lars; Tanzi, Rudolph E

2006-10-27

154

Structure-neurotoxicity relationships of amyloid beta-protein oligomers.  

Science.gov (United States)

Amyloid beta-protein (Abeta) oligomers may be the proximate neurotoxins in Alzheimer's disease (AD). "Oligomer" is an ill-defined term because many kinds have been reported and they often exist in rapid equilibrium with monomers and higher-order assemblies. We report here results of studies in which specific oligomers have been stabilized structurally, fractionated in pure form, and then studied by using a combination of CD spectroscopy, Thioflavin T fluorescence, EM, atomic force microscopy (AFM), and neurotoxicity assays. Abeta monomers were largely unstructured, but oligomers exhibited order-dependent increases in beta-sheet content. EM and AFM data suggest that dimerization and subsequent monomer addition are processes in which significant and asymmetric monomer conformational changes occur. Oligomer secondary structure and order correlated directly with fibril nucleation activity. Neurotoxic activity increased disproportionately (order dependence >1) with oligomer order. The structure-activity correlations reported here significantly extend our understanding of the conformational dynamics, structure, and relative toxicity of pure Abeta oligomers of specific order. PMID:19706468

Ono, Kenjiro; Condron, Margaret M; Teplow, David B

2009-09-01

155

Effects of Stress and Stress Hormones on Amyloid-? Protein and Plaque Deposition  

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Growing evidence indicates that physical and psychosocial stressors, in part acting through the hypothalamic-pituitary-adrenal (HPA) axis, may accelerate the process of Alzheimer’s disease (AD). In this review, we summarize recent research related to the effects of stress and stress hormones on the various disease process elements associated with AD. Specifically, we focus on the relationships among chronic stressors, HPA axis activity, amyloid-? protein, and amyloid-? plaque deposition i...

Dong, Hongxin; Csernansky, John G.

2009-01-01

156

Amyloid precursor protein secretases as therapeutic targets for traumatic brain injury  

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Amyloid-? (A?) peptides, found in Alzheimer’s disease brain, accumulate rapidly after traumatic brain injury (TBI) in both humans and animals. Here we show that blocking either ?- or ?-secretase, enzymes required for production of A? from amyloid precursor protein (APP), can ameliorate motor and cognitive deficits and reduce cell loss after experimental TBI in mice. Thus, APP secretases are promising targets for treatment of TBI.

Loane, David J.; Pocivavsek, Ana; Moussa, Charbel E-h; Thompson, Rachel; Matsuoka, Yasuji; Faden, Alan I.; Rebeck, G. William; Burns, Mark P.

2009-01-01

157

Mutations in amyloid precursor protein affect its interactions with presenilin/?-secretase  

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Alzheimer's disease is characterized by accumulation of toxic ?-amyloid (A?) in the brain and neuronal death. Several mutations in presenilin (PS1) and ?-amyloid precursor protein (APP) associate with an increased A?42/40 ratio. A?42, a highly fibrillogenic species, is believed to drive A? aggregation. Factors shifting ?-secretase cleavage of APP to produce A?42 are unclear. We investigate the molecular mechanism underlying altered A?42/40 ratios associated with APP mutations at codo...

2009-01-01

158

Serum amyloid A stimulates cultured endothelial cells to migrate and proliferate: inhibition by the multikinase inhibitor BIBF1120.  

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In the present study, we tested whether serum amyloid A (SAA) protein, an established biomarker of inflammation, also plays a role in stimulating neovascularization. To evaluate this possibility, human carotid artery endothelial (HCtAE) cells were cultured and cellular migration and the proinflammatory and/or thrombotic activity of SAA (0, 1 or 10 ?g/mL) on vascular endothelial cells was verified by determining gene regulation relative to control (in the absence of SAA). Exposure of HCtAE cells to SAA increased expression of the transcription factor nuclear factor-?B (NFKB), tumour necrosis factor (TNF) and pro-coagulative tissue factor (F3), and stimulated phosphorylation of the P65 subunit of the NFKB complex. Enhanced production of TNF and NFKB was paralleled by increased vascular endothelial growth factor (VEGF) mRNA and protein expression, as demonstrated by quantitative polymerase chain reaction, western blotting and ELISA. Administration of 10 ?g/mL SAA enhanced endothelial cell migration (1.6-fold vs control), stimulated regrowth of HCtAE cells after mechanical injury (~1.2-fold vs control) and increased endothelial tube formation relative to control after 6 h. The SAA-mediated enhancement of endothelial cell migration, proliferation and tube formation were markedly inhibited by pretreatment of HCtAE cells with the multi-angiokinase receptor inhibitor BIBF1120 (100 nmol/L), although SAA-stimulated gene responses for F3 and NFKB were unaffected by 100 nmol/L BIBF1120 pretreatment. Overall, BIBF1120 inhibited the pro-angiogenic activity of SAA on vascular endothelial cells in this experimental model of inflammation. PMID:23819722

Cai, Xiaoping; Freedman, S Ben; Witting, Paul K

2013-09-01

159

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

160

Serum acute phase proteins in dogs with symptomatic esophageal spirocercosis.  

Science.gov (United States)

Canine spirocercosis (CS) is a helminthic infection caused by the nematode Spirocerca lupi. The clinical hallmark of the disease is esophageal dysphagia due to parasite-induced esophageal nodules. Currently, there is limited information on the involvement of serum acute phase proteins (APPs) in the symptomatic CS. The objective of this study was to investigate whether C-reactive protein (CRP), serum amyloid A (SAA), haptoglobin (Hp) and albumin are involved in CS, and if their concentrations measured on admission reflect the severity of benign esophageal lesions. Nineteen dogs with spontaneous symptomatic esophageal spirocercosis and 7 clinically healthy dogs were studied retrospectively. The most consistently increased APP in the symptomatic dogs was Hp (95% of the dogs), followed by CRP (68%). The SAA concentrations were infrequently increased (5% of the dogs), while albumin concentrations were decreased in 58% of the affected dogs. The dogs with spirocercosis had significantly higher median concentrations of Hp (p=0.0001) and CRP (p=0.02) compared to healthy dogs. Median albumin concentrations did not differ between the two groups of dogs. The median concentrations of Hp, CRP and albumin did not differ significantly between the dogs having a single or multiple esophageal nodules. The results of this study indicate that in symptomatic CS, Hp and CRP are significantly and consistently increased, while SAA and albumin may be of limited value as diagnostic markers. No association was established between the concentrations of Hp, CRP and albumin measured on admission and the number of esophageal nodules. PMID:22683300

Mylonakis, Mathios E; Ceron, Jose J; Leontides, Leonidas; Rallis, Tim S; Koutinas, Alexander F

2012-11-23

 
 
 
 
161

Ultraviolet B Irradiation Reduces the Expression of Adiponectin in Ovarial Adipose Tissues through Endocrine Actions of Calcitonin Gene-Related Peptide-Induced Serum Amyloid A  

Science.gov (United States)

Ultraviolet (UV) B irradiation decreases blood adiponectin levels, but the mechanism is not well understood. This study investigated how UVB irradiation reduces adiponectin expression in ovarial adipose tissues. Female Hos:HR-1 hairless mice were exposed to UVB (1.6 J/cm2) irradiation and were killed 24 h later. UVB irradiation decreased the adiponectin protein level in the serum and the adiponectin mRNA level in ovarial adipose tissues. UVB irradiation also decreased the mRNA levels of peroxisome proliferator-activated receptor (PPAR) ?, CCAAT/enhancer binding protein (C/EBP) ?, C/EBP?, and fatty acid binding protein 4 (aP2) in ovarial adipose tissues. In contrast, UVB irradiation increased the mRNA levels of interleukin (IL)-6 and monocyte chemoattractant protein (MCP)-1 in ovarial adipose tissues. In the serum and liver, the levels of serum amyloid A (SAA), involved in PPAR?, C/EBP?, C/EBP?, aP2, IL-6, and MCP-1 regulation, increased after UVB irradiation. The SAA gene is regulated by IL-1?, IL-6, and tumor necrosis factor-?, but only IL-6 expression increased in the liver after UVB irradiation. Additionally, in the liver, hypothalamus, and epidermis, UVB irradiation increased the expression of calcitonin gene-related peptide (CGRP), which upregulates SAA in the liver. Collectively, our results suggest that the CGRP signal induced by skin exposure to UVB transfers to the liver, possibly through the brain, and increases SAA production via IL-6 in the liver. In turn, serum SAA acts in an endocrine manner to decreases the serum adiponectin level by downregulating factors that regulate adiponectin expression in adipose tissues.

Matsui, Sho; Yamane, Takumi; Kobayashi-Hattori, Kazuo; Oishi, Yuichi

2014-01-01

162

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

163

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

164

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

Science.gov (United States)

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, or 40 (for A?40) or 42 (for A?42). The effects of these substitutions were probed using circular dichroism spectroscopy, thioflavin T binding, electron microscopy, PICUP, and mass spectrometry. All peptides displayed a random coil ? ?/? ? ? transition, but substitution-dependent alterations in assembly kinetics and conformer complexity were observed. Tyr1-substituted homologues of A?40 and A?42 assembled the slowest and yielded unusual patterns of oligomer bands in gel electrophoresis experiments, suggesting oligomer compaction had occurred. Consistent with this suggestion was the observation of relatively narrow [Tyr1]A?40 fibrils. Substitution of A?40 at the C terminus decreased the population conformational complexity and substantially extended the highest order of oligomers observed. This latter effect was observed in both A?40 and A?42 as the Tyr substitution position number increased. The ability of a single substitution (Tyr1) to alter A? assembly kinetics and the oligomer frequency distribution suggests that the N terminus is not a benign peptide segment, but rather that A? conformational dynamics and assembly are affected significantly by the competition between the N and C termini to form a stable complex with the central hydrophobic cluster.

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

165

Tolfenamic acid interrupts the de novo synthesis of the ?-amyloid precursor protein and lowers amyloid beta via a transcriptional pathway.  

Science.gov (United States)

Amyloid beta (A?) peptides are related to the pathogenesis of Alzheimer's disease (AD). The search for therapeutic strategies that lower these peptides has mainly focused on the proteolytic processing of the ?-amyloid precursor protein (APP), and other post-transcriptional pathways. The transcription factor specificity protein 1 (Sp1) is vital for the regulation of several genes involved in AD including APP and the beta site APP cleaving enzyme 1 (BACE1). We have previously reported that tolfenamic acid promotes the degradation of Sp1 protein (SP1) in pancreatic human cancer cells and mice tumors. This study examines the ability of tolfenamic acid to reduce SP1 levels, and thereby decrease APP transcription and A? levels in rodent brains. Tolfenamic acid was administered by oral gavage to C57BL/6 mice at variable dosages and for different time periods. Results have shown that tolfenamic acid was able to down regulate brain protein levels of SP1, APP, and A?. These findings demonstrate that interference with upstream transcriptional pathways can lower pathogenic intermediates associated with AD, and thus tolfenamic acid represents a novel approach for the development of a therapeutic intervention for AD. PMID:21557719

Adwan, L I; Basha, R; Abdelrahim, M; Subaiea, G M; Zawia, N H

2011-06-01

166

Soluble Amyloid Precursor Protein 770 Is Released from Inflamed Endothelial Cells and Activated Platelets  

Science.gov (United States)

Most Alzheimer disease (AD) patients show deposition of amyloid ? (A?) peptide in blood vessels as well as the brain parenchyma. We previously found that vascular endothelial cells express amyloid ? precursor protein (APP) 770, a different APP isoform from neuronal APP695, and produce A?. Since the soluble APP cleavage product, sAPP, is considered to be a possible marker for AD diagnosis, sAPP has been widely measured as a mixture of these variants. We hypothesized that measurement of the endothelial APP770 cleavage product in patients separately from that of neuronal APP695 would enable discrimination between endothelial and neurological dysfunctions. Using our newly developed ELISA system for sAPP770, we observed that inflammatory cytokines significantly enhanced sAPP770 secretion by endothelial cells. Furthermore, we unexpectedly found that sAPP770 was rapidly released from activated platelets. We also found that cerebrospinal fluid mainly contained sAPP695, while serum mostly contained sAPP770. Finally, to test our hypothesis that sAPP770 could be an indicator for endothelial dysfunction, we applied our APP770 ELISA to patients with acute coronary syndrome (ACS), in which endothelial injury and platelet activation lead to fibrous plaque disruption and thrombus formation. Development of a biomarker is essential to facilitate ACS diagnosis in clinical practice. The results revealed that ACS patients had significantly higher plasma sAPP770 levels. Furthermore, in myocardial infarction model rats, an increase in plasma sAPP preceded the release of cardiac enzymes, currently used markers for acute myocardial infarction. These findings raise the possibility that sAPP770 can be a useful biomarker for ACS.

Kitazume, Shinobu; Yoshihisa, Akiomi; Yamaki, Takayoshi; Oikawa, Masayoshi; Tachida, Yuriko; Ogawa, Kazuko; Imamaki, Rie; Hagiwara, Yoshiaki; Kinoshita, Noriaki; Takeishi, Yasuchika; Furukawa, Katsutoshi; Tomita, Naoki; Arai, Hiroyuki; Iwata, Nobuhisa; Saido, Takaomi; Yamamoto, Naomasa; Taniguchi, Naoyuki

2012-01-01

167

Proteomic evaluation of sheep serum proteins  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The applications of proteomic strategies to ovine medicine remain limited. The definition of serum proteome may be a good tool to identify useful protein biomarkers for recognising sub-clinical conditions and overt disease in sheep. Findings from bovine species are often directly translated for use in ovine medicine. In order to characterize normal protein patterns and improve knowledge of molecular species-specific characteristics, we generated a two-dimensional reference map of sheep serum. The possible application of this approach was tested by analysing serum protein patterns in ewes with mild broncho-pulmonary disease, which is very common in sheep and in the peripartum period which is a stressful time, with a high incidence of infectious and parasitic diseases. Results This study generated the first reference 2-DE maps of sheep serum. Overall, 250 protein spots were analyzed, and 138 identified. Compared with healthy sheep, serum protein profiles of animals with rhino-tracheo-bronchitis showed a significant decrease in protein spots identified as transthyretin, apolipoprotein A1 and a significant increase in spots identified as haptoglobin, endopin 1b and alpha1B glycoprotein. In the peripartum period, haptoglobin, alpha-1-acid glycoprotein, apolipoprotein A1 levels rose, while transthyretin content dropped. Conclusions This study describes applications of proteomics in putative biomarker discovery for early diagnosis as well as for monitoring the physiological and metabolic situations critical for ovine welfare.

Chiaradia Elisabetta

2012-05-01

168

Amyloid-beta peptide binds to microtubule-associated protein 1B (MAP1B).  

Science.gov (United States)

Extracellular and intraneuronal formation of amyloid-beta aggregates have been demonstrated to be involved in the pathogenesis of Alzheimer's disease. However, the precise mechanism of amyloid-beta neurotoxicity is not completely understood. Previous studies suggest that binding of amyloid-beta to a number of targets have deleterious effects on cellular functions. In the present study we have shown for the first time that amyloid-beta 1-42 bound to a peptide comprising the microtubule binding domain of the heavy chain of microtubule-associated protein 1B by the screening of a human brain cDNA library expressed on M13 phage. This interaction may explain, in part, the loss of neuronal cytoskeletal integrity, impairment of microtubule-dependent transport and synaptic dysfunction observed previously in Alzheimer's disease. PMID:18079022

Gevorkian, Goar; Gonzalez-Noriega, Alfonso; Acero, Gonzalo; Ordoñez, Jorge; Michalak, Colette; Munguia, Maria Elena; Govezensky, Tzipe; Cribbs, David H; Manoutcharian, Karen

2008-05-01

169

AMYLOID-? PEPTIDE BINDS TO MICROTUBULE-ASSOCIATED PROTEIN 1B (MAP1B)  

Science.gov (United States)

Extracellular and intraneuronal formation of amyloid-beta aggregates have been demonstrated to be involved in the pathogenesis of Alzheimer’s disease. However, the precise mechanism of amyloid-beta neurotoxicity is not completely understood. Previous studies suggest that binding of amyloid-beta to a number of targets have deleterious effects on cellular functions. In the present study we have shown for the first time that amyloid-beta 1-42 bound to a peptide comprising the microtubule binding domain of the heavy chain of microtubule-associated protein 1B by the screening of a human brain cDNA library expressed on M13 phage. This interaction may explain, in part, the loss of neuronal cytoskeletal integrity, impairment of microtubule-dependent transport and synaptic dysfunction observed previously in Alzheimer’s disease.

Gevorkian, Goar; Gonzalez-Noriega, Alfonso; Acero, Gonzalo; Ordonez, Jorge; Michalak, Colette; Munguia, Maria Elena; Govezensky, Tzipe; Cribbs, David H.; Manoutcharian, Karen

2008-01-01

170

Glutamate system, amyloid ß peptides and tau protein: functional interrelationships and relevance to Alzheimer disease pathology.  

Science.gov (United States)

Alzheimer disease is the most prevalent form of dementia globally and is characterized premortem by a gradual memory loss and deterioration of higher cognitive functions and postmortem by neuritic plaques containing amyloid ß peptide and neurofibrillary tangles containing phospho-tau protein. Glutamate is the most abundant neurotransmitter in the brain and is essential to memory formation through processes such as long-term potentiation and so might be pivotal to Alzheimer disease progression. This review discusses how the glutamatergic system is impaired in Alzheimer disease and how interactions of amyloid ß and glutamate influence synaptic function, tau phosphorylation and neurodegeneration. Interestingly, glutamate not only influences amyloid ß production, but also amyloid ß can alter the levels of glutamate at the synapse, indicating that small changes in the concentrations of both molecules could influence Alzheimer disease progression. Finally, we describe how the glutamate receptor antagonist, memantine, has been used in the treatment of individuals with Alzheimer disease and discuss its effectiveness. PMID:22894822

Revett, Timothy J; Baker, Glen B; Jhamandas, Jack; Kar, Satyabrata

2013-01-01

171

Glutamate system, amyloid ? peptides and tau protein: functional interrelationships and relevance to Alzheimer disease pathology  

Science.gov (United States)

Alzheimer disease is the most prevalent form of dementia globally and is characterized premortem by a gradual memory loss and deterioration of higher cognitive functions and postmortem by neuritic plaques containing amyloid ? peptide and neurofibrillary tangles containing phospho-tau protein. Glutamate is the most abundant neurotransmitter in the brain and is essential to memory formation through processes such as long-term potentiation and so might be pivotal to Alzheimer disease progression. This review discusses how the glutamatergic system is impaired in Alzheimer disease and how interactions of amyloid ? and glutamate influence synaptic function, tau phosphorylation and neurodegeneration. Interestingly, glutamate not only influences amyloid ? production, but also amyloid ? can alter the levels of glutamate at the synapse, indicating that small changes in the concentrations of both molecules could influence Alzheimer disease progression. Finally, we describe how the glutamate receptor antagonist, memantine, has been used in the treatment of individuals with Alzheimer disease and discuss its effectiveness.

Revett, Timothy J.; Baker, Glen B.; Jhamandas, Jack; Kar, Satyabrata

2013-01-01

172

Serum Amyloid P Component Prevents High-Density Lipoprotein-Mediated Neutralization of Lipopolysaccharide  

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Lipopolysaccharide (LPS) is an amphipathic macromolecule that is highly aggregated in aqueous preparations. LPS-binding protein (LBP) catalyzes the transfer of single LPS molecules, segregated from an LPS aggregate, to high-density lipoproteins (HDL), which results in the neutralization of LPS. When fluorescein isothiocyanate-labeled LPS (FITC-LPS) is used, this transfer of LPS monomers to HDL can be measured as an increase in fluorescence due to dequenching of FITC-LPS. Recently, serum amylo...

2000-01-01

173

A common mechanism underlying amyloid fibrillation and protein crystallization revealed by the effects of ultrasonication.  

Science.gov (United States)

Protein crystals form in supersaturated solutions via a nucleation and growth mechanism. The amyloid fibrils of denatured proteins also form via a nucleation and growth mechanism. This similarity suggests that, although protein crystals and amyloid fibrils are distinct in their morphologies, both processes can be controlled in a similar manner. It has been established that ultrasonication markedly accelerates the formation of amyloid fibrils and simultaneously breaks them down into fragmented fibrils. In this study, we investigated the effects of ultrasonication on the crystallization of hen egg white lysozyme and glucose isomerase from Streptomyces rubiginosus. Protein crystallization was monitored by light scattering, tryptophan fluorescence, and light transmittance. Repeated ultrasonic irradiations caused the crystallization of lysozyme and glucose isomerase after cycles of irradiations. The size of the ultrasonication-induced crystals was small and homogeneous, and their numbers were larger than those obtained under quiescent conditions. Switching off ultrasonic irradiation when light scattering or tryptophan fluorescence began to change resulted in the formation of larger crystals due to the suppression of the further nucleation and fractures in preformed crystals. The results indicate that protein crystallization and amyloid fibrillation are explained on the basis of a common phase diagram in which ultrasonication accelerates the formation of crystals or crystal-like amyloid fibrils as well as fragmentation of preformed crystals or fibrils. PMID:24096102

Kitayama, Hiroki; Yoshimura, Yuichi; So, Masatomo; Sakurai, Kazumasa; Yagi, Hisashi; Goto, Yuji

2013-12-01

174

Recombinant human serum amyloid P in healthy volunteers and patients with pulmonary fibrosis.  

Science.gov (United States)

PRM-151, recombinant human Pentraxin-2 (PTX-2) also referred to as serum amyloid P (SAP), is under development for treatment of fibrosis. A First-in-Human (FIH) trial was performed to assess the safety, tolerability, and pharmacokinetics of single ascending intravenous doses of PRM-151 administered to healthy subjects, using a randomized, blinded, placebo controlled study design. Each cohort included three healthy subjects (PRM-151:placebo; 2:1). SAP levels were assessed using a validated ELISA method, non-discriminating between endogenous and exogenous SAP. At a dose level of 10 mg/kg, at which a physiologic plasma level of SAP was reached, two additional healthy volunteers and three pulmonary fibrosis (PF) patients were enrolled enabling comparison of the pharmacokinetic SAP profile between healthy volunteers and PF patients. In addition, the percentage of fibrocytes (CD45+/Procollagen-1+ cells) in whole blood samples was assessed to demonstrate biological activity of PRM-151 in the target population. PRM-151 administration was generally well tolerated. In two pulmonary fibrosis patients non-specific, transient skin reactions (urticaria and erythema) were observed. PRM-151 administration resulted in a 6-to 13-fold increase in mean baseline plasma SAP levels at dose levels of 5, 10, and 20 mg/kg. The estimated t1/2 of PRM-151 in healthy volunteers was 30 h. Pharmacokinetic profiles were comparable between healthy volunteers and PF patients. PRM-151 administration resulted in a 30-50% decrease in fibrocyte numbers 24 h post-dose. This suggests that administration of PRM-151 may be associated with a reduction of fibrocytes in PF patients, a population for which current pharmacotherapeutic options are limited. The pharmacological action of PRM-151 should be confirmed in future research. PMID:23380438

Dillingh, M R; van den Blink, B; Moerland, M; van Dongen, M G J; Levi, M; Kleinjan, A; Wijsenbeek, M S; Lupher, M L; Harper, D M; Getsy, J A; Hoogsteden, H C; Burggraaf, J

2013-12-01

175

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)

1981-06-19

176

Amyloid-binding compounds maintain protein homeostasis during ageing and extend lifespan  

Science.gov (United States)

Genetic studies indicate that protein homeostasis is a major contributor to metazoan longevity1. Collapse of protein homeostasis results in protein misfolding cascades and the accumulation of insoluble protein fibrils and aggregates, such as amyloids2. A group of small molecules, traditionally used in histopathology to stain amyloid in tissues, bind protein fibrils and slow aggregation in vitro and in cell culture3,4. We proposed that treating animals with such compounds would promote protein homeostasis in vivo and increase longevity. Here we show that exposure of adult Caenorhabditis elegans to the amyloid-binding dye Thioflavin T (ThT) resulted in a profoundly extended lifespan and slowed ageing. ThT also suppressed pathological features of mutant metastable proteins and human ?-amyloid-associated toxicity. These beneficial effects of ThT depend on the protein homeostasis network regulator heat shock factor 1 (HSF-1), the stress resistance and longevity transcription factor SKN-1, molecular chaperones, autophagy and proteosomal functions. Our results demonstrate that pharmacological maintenance of the protein homeostatic network has a profound impact on ageing rates, prompting the development of novel therapeutic interventions against ageing and age-related diseases.

Alavez, Silvestre; Vantipalli, Maithili C.; Zucker, David J. S.; Klang, Ida M.; Lithgow, Gordon J.

2013-01-01

177

Cheetahs have 4 serum amyloid a genes evolved through repeated duplication events.  

Science.gov (United States)

Amyloid A (AA) amyloidosis is a leading cause of mortality in captive cheetahs (Acinonyx jubatus). We performed genome walking and PCR cloning and revealed that cheetahs have 4 SAA genes (provisionally named SAA1A, SAA1B, SAA3A, and SAA3B). In addition, we identified multiple nucleotide polymorphisms in the 4 SAA genes by screening 51 cheetahs. The polymorphisms defined 4, 7, 6, and 4 alleles for SAA1A, SAA3A, SAA1B, and SAA3B, respectively. Pedigree analysis of the inheritance of genotypes for the SAA genes revealed that specific combinations of alleles for the 4 SAA genes cosegregated as a unit (haplotype) in pedigrees, indicating that the 4 genes were linked on the same chromosome. Notably, cheetah SAA1A and SAA1B were highly homologous in their nucleotide sequences. Likewise, SAA3A and SAA3B genes were homologous. These observations suggested a model for the evolution of the 4 SAA genes in cheetahs in which duplication of an ancestral SAA gene first gave rise to SAA1 and SAA3. Subsequently, each gene duplicated one more time, uniquely making 4 genes in the cheetah genome. The monomorphism of the cheetah SAA1A protein might be one of the factors responsible for the high incidence of AA amyloidosis in this species. PMID:21987659

Chen, Lei; Une, Yumi; Higuchi, Keiichi; Mori, Masayuki

2012-01-01

178

Pentraxin-chromatin interactions: serum amyloid P component specifically displaces H1-type histones and solubilizes native long chromatin  

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Pure serum amyloid P component (SAP) and native long chromatin, mixed together at wt/wt ratios between 1:1 and 1:2 in the presence of physiological concentrations of NaCl and calcium, both remained in solution, whereas each alone precipitates rapidly under these conditions. This solubilization accompanies the binding of SAP to chromatin and the displacement of H1-type histones, which are essential for condensation and higher order folding of chromatin. Such binding of SAP to chromatin is rema...

1990-01-01

179

Calcium regulates the interaction of amyloid precursor protein with Homer3 protein.  

Science.gov (United States)

Ca(2+) dysregulation is an important factor implicated in Alzheimer's disease pathogenesis. The mechanisms mediating the reciprocal regulation of Ca(2+) homeostasis and amyloid precursor protein (APP) metabolism, function, and protein interactions are not well known. We have previously shown that APP interacts with Homer proteins, which inhibit APP processing toward amyloid-?. In this study, we investigated the effect of Ca(2+) homeostasis alterations on APP/Homer3 interaction. Influx of extracellular Ca(2+) upon treatment of HEK293 cells with the ionophore A23187 or addition of extracellular Ca(2+) in cells starved of calcium specifically reduced APP/Homer3 but not APP/X11a interaction. Endoplasmic reticulum Ca(2+) store depletion by thapsigargin followed by store-operated calcium entry also decreased the interaction. Interestingly, application of a phospholipase C stimulator, which causes inositol 1,4,5-trisphosphate-induced endoplasmic reticulum Ca(2+) release, caused dissociation of APP/Homer3 complex. In human neuroblastoma cells, membrane depolarization also disrupted the interaction. This is the first study showing that changes in Ca(2+) homeostasis affect APP protein interactions. Our results suggest that Ca(2+) and Homers play a significant role in the development of Alzheimer's disease pathology. PMID:24792907

Kyratzi, Elli; Efthimiopoulos, Spiros

2014-09-01

180

Amyloid fibrils in human insulinoma and islets of Langerhans of the diabetic cat are derived from a neuropeptide-like protein also present in normal islet cells.  

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Amyloid deposits localized to the islets of Langerhans are typical of non-insulin-dependent human diabetes mellitus and of diabetes mellitus in adult cats. Amyloid deposits also commonly occur in insulin-producing pancreatic tumors. We have purified a major protein--insulinoma or islet amyloid polypeptide (IAPP)--from human and cat islet amyloid and from amyloid of a human insulinoma. IAPP from human insulinoma contained 37 amino acid residues and had a theoretical molecular mass of 3850 Da. ...

Westermark, P.; Wernstedt, C.; Wilander, E.; Hayden, D. W.; O Brien, T. D.; Johnson, K. H.

1987-01-01

 
 
 
 
181

Oxidation Enhances Human Serum Albumin Thermal Stability and Changes the Routes of Amyloid Fibril Formation  

Science.gov (United States)

Oxidative damages are linked to several aging-related diseases and are among the chemical pathways determining protein degradation. Specifically, interplay of oxidative stress and protein aggregation is recognized to have a link to the loss of cellular function in pathologies like Alzheimer's and Parkinson's diseases. Interaction between protein and reactive oxygen species may indeed induce small changes in protein structure and lead to the inhibition/modification of protein aggregation process, potentially determining the formation of species with different inherent toxicity. Understanding the temperate relationship between these events can be of utmost importance in unraveling the molecular basis of neurodegeneration. In this work, we investigated the effect of hydrogen peroxide oxidation on Human Serum Albumin (HSA) structure, thermal stability and aggregation properties. In the selected conditions, HSA forms fibrillar aggregates, while the oxidized protein undergoes aggregation via new routes involving, in different extents, specific domains of the molecule. Minute variations due to oxidation of single residues affect HSA tertiary structure leading to protein compaction, increased thermal stability, and reduced association propensity.

Sancataldo, Giuseppe; Vetri, Valeria; Fodera, Vito; Di Cara, Gianluca; Militello, Valeria; Leone, Maurizio

2014-01-01

182

Augmented Senile Plaque Load in Aged Female ?-Amyloid Precursor Protein-Transgenic Mice  

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Transgenic mice (Tg2576) overexpressing human ?-amyloid precursor protein with the Swedish mutation (APP695SWE) develop Alzheimer’s disease-like amyloid ? protein (A?) deposits by 8 to 10 months of age. These mice show elevated levels of A?40 and A?42, as well as an age-related increase in diffuse and compact senile plaques in the brain. Senile plaque load was quantitated in the hippocampus and neocortex of 8- to 19-month-old male and female Tg2576 mice. In all mice, plaque burden incr...

Callahan, Michael J.; Lipinski, William J.; Bian, Feng; Durham, Robert A.; Pack, Amy; Walker, Lary C.

2001-01-01

183

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

184

Gelsolin-related amyloidosis. Identification of the amyloid protein in Finnish hereditary amyloidosis as a fragment of variant gelsolin.  

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The Finnish type of familial amyloidosis is a systemic disease characterized by progressive cranial neuropathy, corneal lattice dystrophy, and distal sensimotor neuropathy. Amyloid fibrils were isolated from the kidney and heart of a patient with Finnish amyloidosis. After solubilization, the amyloid proteins were fractionated by gel filtration and purified by reverse-phase HPLC. Complete amino acid sequence analyses show that the two amyloid components obtained are fragments of gelsolin, an ...

Maury, C. P.

1991-01-01

185

Topographical relationship between beta-amyloid and tau protein epitopes in tangle-bearing cells in Alzheimer disease.  

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Double-labeling immunohistochemistry was used to investigate the topographical relationship between beta-amyloid and tau protein epitopes present in cells bearing neurofibrillary tangles found in the hippocampal formation of patients with Alzheimer disease. An antiserum raised against the amino terminus of beta-amyloid stained numerous tangle-bearing cells and other bodies ("extracellular tangles"), but double labeling showed that the beta-amyloid staining is invariably peripheral to that of ...

Spillantini, M. G.; Goedert, M.; Jakes, R.; Klug, A.

1990-01-01

186

Expression of amyloid precursor protein in human astrocytes in vitro: isoform-specific increases following heat shock.  

Science.gov (United States)

The beta-amyloid protein deposited in senile plaques and cerebral blood vessels in the Alzheimer's disease brain is derived from the larger transmembrane spanning amyloid precursor protein. The present study investigates the effects of heat shock on the expression and processing of amyloid precursor protein in a normal human fetal astrocytic cell line CC2565 using reverse transcription-polymerase chain reaction, in situ hybridization histochemistry and western blot analysis. Heat shock led to an increase in the messenger RNA encoding Kunitz protease inhibitor isoforms of amyloid precursor protein, which peaked at 4h post-heat shock. This increase was confined to the messenger RNA encoding amyloid precursor protein-751, with a decrease in amyloid precursor protein-770 and no change in amyloid precursor protein-695. This shift in splicing was accompanied by a significant decrease in secreted amyloid precursor protein and an increase in beta-secretase processing within the cell. These findings demonstrate that astrocytes in vitro demonstrate a striking response to heat shock. This is unlikely to be due to a direct action on the promoter region of the gene, since the response is specific for one splice variant; amyloid precursor protein-751 messenger RNA. This increase in expression is further accompanied by a decrease in secretion of amyloid precursor protein, implying a shift in processing towards an intracellular route, possibly via the actions of the beta-secretase enzyme, which is known to be potentially amyloidogenic. Such a mechanism may contribute to amyloidosis in the intact brain in response to cellular stress, such as head injury. PMID:10938437

Shepherd, C E; Bowes, S; Parkinson, D; Cambray-Deakin, M; Pearson, R C

2000-01-01

187

Amyloid-? protein oligomerization and the importance of tetramers and dodecamers in the aetiology of Alzheimer's disease  

Science.gov (United States)

In recent years, small protein oligomers have been implicated in the aetiology of a number of important amyloid diseases, such as type 2 diabetes, Parkinson’s disease and Alzheimer’s disease. As a consequence, research efforts are being directed away from traditional targets, such as amyloid plaques, and towards characterization of early oligomer states. Here we present a new analysis method, ion mobility coupled with mass spectrometry, for this challenging problem, which allows determination of in vitro oligomer distributions and the qualitative structure of each of the aggregates. We applied these methods to a number of the amyloid-? protein isoforms of A?40 and A?42 and showed that their oligomer-size distributions are very different. Our results are consistent with previous observations that A?40 and A?42 self-assemble via different pathways and provide a candidate in the A?42 dodecamer for the primary toxic species in Alzheimer’s disease.

Bernstein, Summer L.; Dupuis, Nicholas F.; Lazo, Noel D.; Wyttenbach, Thomas; Condron, Margaret M.; Bitan, Gal; Teplow, David B.; Shea, Joan-Emma; Ruotolo, Brandon T.; Robinson, Carol V.; Bowers, Michael T.

2010-01-01

188

Amyloid-? protein oligomerization and the importance of tetramers and dodecamers in the aetiology of Alzheimer's disease.  

Science.gov (United States)

In recent years, small protein oligomers have been implicated in the aetiology of a number of important amyloid diseases, such as type 2 diabetes, Parkinson's disease and Alzheimer's disease. As a consequence, research efforts are being directed away from traditional targets, such as amyloid plaques, and towards characterization of early oligomer states. Here we present a new analysis method, ion mobility coupled with mass spectrometry, for this challenging problem, which allows determination of in vitro oligomer distributions and the qualitative structure of each of the aggregates. We applied these methods to a number of the amyloid-? protein isoforms of A?40 and A?42 and showed that their oligomer-size distributions are very different. Our results are consistent with previous observations that A?40 and A?42 self-assemble via different pathways and provide a candidate in the A?42 dodecamer for the primary toxic species in Alzheimer's disease. PMID:20703363

Bernstein, Summer L; Dupuis, Nicholas F; Lazo, Noel D; Wyttenbach, Thomas; Condron, Margaret M; Bitan, Gal; Teplow, David B; Shea, Joan-Emma; Ruotolo, Brandon T; Robinson, Carol V; Bowers, Michael T

2009-07-01

189

Self-assembly of protein amyloid: a competition between amorphous and ordered aggregation  

CERN Document Server

Protein aggregation in the form of amyloid fibrils has important biological and technological implications. Although the self-assembly process is highly efficient, aggregates not in the fibrillar form would also occur and it is important to include these disordered species when discussing the thermodynamic equilibrium behavior of the system. Here, we initiate such a task by considering a mixture of monomeric proteins and the corresponding aggregates in the disordered form (micelles) and in the fibrillar form (amyloid fibrils). Starting with a model on the respective binding free energies for these species, we calculate their concentrations at thermal equilibrium. We then discuss how the incorporation of the disordered structure furthers our understanding on the various amyloid promoting factors observed empirically, and on the kinetics of fibrilization.

Lee, Chiu Fan

2010-01-01

190

Proteomic evaluation of sheep serum proteins  

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Abstract Background The applications of proteomic strategies to ovine medicine remain limited. The definition of serum proteome may be a good tool to identify useful protein biomarkers for recognising sub-clinical conditions and overt disease in sheep. Findings from bovine species are often directly translated for use in ovine medicine. In order to characterize normal protein patterns and improve knowledge of molecular species-specific characteristics, we generated a two-dime...

Chiaradia Elisabetta; Avellini Luca; Tartaglia Micaela; Gaiti Alberto; Just Ingo; Scoppetta Fausto; Czentnar Zoltan; Pich Andreas

2012-01-01

191

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

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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

192

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.

2012-03-23

193

Alzheimer Precursor Protein Interaction with the Nogo-66 Receptor Reduces Amyloid-? Plaque Deposition  

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Pathophysiologic hypotheses for Alzheimer’s disease (AD) are centered on the role of the amyloid plaque A?peptide and the mechanism of its derivation from the amyloid precursor protein (APP). As part of the disease process, an aberrant axonal sprouting response is known to occur near A? deposits. A Nogo to Nogo-66 receptor (NgR) pathway contributes to determining the ability of adult CNS axons to extend after traumatic injuries. Here, we consider the potential role of NgR mechanisms in AD...

Park, James H.; Gimbel, David A.; Grandpre, Tadzia; Lee, Jung-kil; Kim, Ji-eun; Li, Weiwei; Lee, Daniel H. S.; Strittmatter, Stephen M.

2006-01-01

194

Thermal stability and conformational transitions of scrapie amyloid (prion) protein correlate with infectivity.  

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The scrapie amyloid (prion) protein (PrP27-30) is the protease-resistant core of a larger precursor (PrPSc) and a component of the infectious scrapie agent; the potential to form amyloid is a result of posttranslational event or conformational abnormality. The conformation, heat stability, and solvent-induced conformational transitions of PrP27-30 were studied in the solid state in films by CD spectroscopy and correlated with the infectivity of rehydrated and equilibrated films. The exposure ...

Safar, J.; Roller, P. P.; Gajdusek, D. C.; Gibbs, C. J.

1993-01-01

195

[Effect of fullerenes C60 on the amyloids of X-protein].  

Science.gov (United States)

The inhibitory effect of hydrated fullerene C60 (HyFn) and the sodium salt of the fullerene polycarboxylic derivative C60Cl (C6H4CH2COONa)5 on the formation of amyloid fibrils by X-protein in vitro has been studied by electron microscopy. It has been shown that these compounds not only destroyed mature amyloid fibrils but also prevented the formation of new fibrils. This property of fullerenes, nanoparticles, can be used for the development of a novel medicinal nanotechnology in the therapy of amyloidoses. PMID:19402528

Marsagishvili, L G; Bobylev, A G; Shpagina, M D; Troshin, P A; Podlubnaia, Z A

2009-01-01

196

Prion protein preamyloid and amyloid deposits in Gerstmann-Sträussler-Scheinker disease, Indiana kindred.  

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Gerstmann-Sträussler-Scheinker disease (GSS) is a familial neurological disorder pathologically characterized by amyloid deposition in the cerebrum and cerebellum. In GSS, the amyloid is immunoreactive to antisera raised against the prion protein (PrP) 27-30, a proteinase K-resistant peptide of 27-30 kDa that is derived by limited proteolysis from an abnormal isoform of a neuronal sialoglycoprotein of 33-35 kDa designated PrPSc. Polyclonal antibodies raised against synthetic peptides homolog...

Giaccone, G.; Verga, L.; Bugiani, O.; Frangione, B.; Serban, D.; Prusiner, S. B.; Farlow, M. R.; Ghetti, B.; Tagliavini, F.

1992-01-01

197

Seizure Susceptibility and Mortality in Mice that Over-Express Amyloid Precursor Protein  

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Alzheimer's disease and Fragile X syndrome both display synaptic phenotypes, and based on recent studies, likely share dendritic over expression of amyloid precursor protein (APP) and ?-amyloid (A?). In order to create a mouse model to specifically study the effects of APP and A? at synapses, we crossed Tg2576, which over-express human APP with the Swedish mutation (hAPPsw), with fmr-1 KO mice. The progeny, named FRAXAD, displayed increased mortality (23% by 30 days of age) compared to Tg2...

Westmark, Cara J.; Westmark, Pamela R.; Beard, Ashley M.; Hildebrandt, Sharon M.; Malter, James S.

2008-01-01

198

The Beta-Amyloid Protein of Alzheimer's Disease: Communication Breakdown by Modifying the Neuronal Cytoskeleton  

Science.gov (United States)

Alzheimer's disease (AD) is one of the most prevalent severe neurological disorders afflicting our aged population. Cognitive decline, a major symptom exhibited by AD patients, is associated with neuritic dystrophy, a degenerative growth state of neurites. The molecular mechanisms governing neuritic dystrophy remain unclear. Mounting evidence indicates that the AD-causative agent, ?-amyloid protein (A?), induces neuritic dystrophy. Indeed, neuritic dystrophy is commonly found decorating A?-rich amyloid plaques (APs) in the AD brain. Furthermore, disruption and degeneration of the neuronal microtubule system in neurons forming dystrophic neurites may occur as a consequence of A?-mediated downstream signaling. This review defines potential molecular pathways, which may be modulated subsequent to A?-dependent interactions with the neuronal membrane as a consequence of increasing amyloid burden in the brain.

Mokhtar, Sara H.; Bakhuraysah, Maha M.; Cram, David S.; Petratos, Steven

2013-01-01

199

Amyloid ?-protein, Cystatin C and Cathepsin B as Biomarkers of Alzheimer's Disease  

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It is suggested that Alzheimer’s disease (AD) is caused by an imbalance between production, degradation and clearance of the amyloid-? (A?) protein. This imbalance leads to aggregation of A? and tau proteins and neurodegeneration in the brain. Today there is increasing evidence that the balance between the protease cathepsin B and the protease inhibitor cystatin C affects the tendency for A? to aggregate. The primary aim of this thesis was to investigate A?, cystatin C and cathepsin B ...

Sundelo?f, Johan

2010-01-01

200

Metalloprotease Meprin beta Generates Nontoxic N-terminal Amyloid Precursor Protein Fragments in Vivo  

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Identification of physiologically relevant substrates is still the most challenging part in protease research for understanding the biological activity of these enzymes. The zinc-dependent metalloprotease meprin beta is known to be expressed in many tissues with functions in health and disease. Here, we demonstrate unique interactions between meprin beta and the amyloid precursor protein (APP). Although APP is intensively studied as a ubiquitously expressed cell surface protein, which is invo...

2011-01-01

 
 
 
 
201

Self-assembly of protein amyloid: a competition between amorphous and ordered aggregation  

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Protein aggregation in the form of amyloid fibrils has important biological and technological implications. Although the self-assembly process is highly efficient, aggregates not in the fibrillar form would also occur and it is important to include these disordered species when discussing the thermodynamic equilibrium behavior of the system. Here, we initiate such a task by considering a mixture of monomeric proteins and the corresponding aggregates in the disordered form (m...

Lee, Chiu Fan

2008-01-01

202

Adipose Tissue-Derived Human Serum Amyloid A Does Not Affect Atherosclerotic Lesion Area in hSAA1+/?/ApoE?/? Mice  

Science.gov (United States)

Chronically elevated serum levels of serum amyloid A (SAA) are linked to increased risk of cardiovascular disease. However, whether SAA is directly involved in atherosclerosis development is still not known. The aim of this study was to investigate the effects of adipose tissue-derived human SAA on atherosclerosis in mice. hSAA1+/? transgenic mice (hSAA1 mice) with a specific expression of human SAA1 in adipose tissue were bred with ApoE-deficient mice. The hSAA1 mice and their wild type (wt) littermates were fed normal chow for 35 weeks. At the end of the experiment, the mice were euthanized and blood, gonadal adipose tissue and aortas were collected. Plasma levels of SAA, cholesterol and triglycerides were measured. Atherosclerotic lesion areas were analyzed in the aortic arch, the thoracic aorta and the abdominal aorta in en face preparations of aorta stained with Sudan IV. The human SAA protein was present in plasma from hSAA1 mice but undetectable in wt mice. Similar plasma levels of cholesterol and triglycerides were observed in hSAA1 mice and their wt controls. There were no differences in atherosclerotic lesion areas in any sections of the aorta in hSAA1 mice compared to wt mice. In conclusion, our data suggest that adipose tissue-derived human SAA does not influence atherosclerosis development in mice.

Ahlin, Sofie; Olsson, Maja; Wilhelmson, Anna S.; Skalen, Kristina; Boren, Jan; Carlsson, Lena M. S.; Svensson, Per-Arne; Sjoholm, Kajsa

2014-01-01

203

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

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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

204

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

2009-03-01

205

Production of recombinant protein C in serum-containing and serum-free perfusion culture.  

Science.gov (United States)

For the development of a perfusion culture producing recombinant human protein C, the effects of fetal calf serum and growth factors on cell growth and recombinant protein production were investigated. Although the growth of recombinant cells was stimulated by serum in a dose-dependent manner, a lower concentration of serum (2%) could support both synthesis and post-translational modification of protein C as efficiently as 10% serum. Among the growth factors tested, transferrin enhanced protein C production to the level comparable with 10% serum, while insulin was effective in maintaining cellular metabolism. Based on these results, a perfusion culture for a scale-up production of recombinant protein C was done using an Opticell culture system. A good productivity of the recombinant protein was obtained in low serum or serum-free medium for more than one month. PMID:1368118

Sugiura, T; Maruyama, H B

1991-11-01

206

Amyloid ?-protein: A?40 Inhibits A?42 Oligomerization  

Science.gov (United States)

A?40 and A?42 are peptides that adopt similar random coil structures in solution. A?42, however, is significantly more neurotoxic than A?40 and forms amyloid fibrils much faster than A?40. Here, mass spectrometry and ion mobility spectrometry are used to investigate a mixture of A?40 and A?42. The mass spectrum for the mixed solution shows the presence of a hetero-oligomer, composed of equal parts of A?40 and A?42. Ion mobility results indicate that this mixed species comprises an oligomer distribution extending to tetramer. A?40 alone produces such a distribution, whereas A?42 alone produces oligomers of order up to dodecamer. This indicates that A?40 inhibits A?42 oligomerization.

Murray, Megan M.; Bernstein, Summer L.; Nyugen, Vy; Condron, Margaret M.; Teplow, David B.; Bowers, Michael T.

2009-01-01

207

Amyloid beta protein: Abeta40 inhibits Abeta42 oligomerization.  

Science.gov (United States)

Abeta40 and Abeta42 are peptides that adopt similar random-coil structures in solution. Abeta42, however, is significantly more neurotoxic than Abeta40 and forms amyloid fibrils much more rapidly than Abeta40. Here, mass spectrometry and ion mobility spectrometry are used to investigate a mixture of Abeta40 and Abeta42. The mass spectrum for the mixed solution shows the presence of a heterooligomer composed of equal parts of Abeta40 and Abeta42. Ion mobility results indicate that this mixed species comprises an oligomer distribution extending to tetramers. Abeta40 alone produces such a distribution, whereas Abeta42 alone produces oligomers as large as dodecamers. This indicates that Abeta40 inhibits Abeta42 oligomerization. PMID:19385598

Murray, Megan M; Bernstein, Summer L; Nyugen, Vy; Condron, Margaret M; Teplow, David B; Bowers, Michael T

2009-05-13

208

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

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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

209

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

1988-01-01

210

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

1988-01-01

211

Amyloid accomplices and enforcers  

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Amyloid-related diseases are often ascribed to protein “misfolding.” Yet in the absence of high-resolution structures for mature fibrils or intermediates, the connection between the mechanism of amyloid formation and protein folding remains tenuous. The simplistic view of amyloid fibrillogenesis as a homogeneous self-assembly process is being increasingly challenged by observations that amyloids interact with a variety of cofactors including metals, glycosaminoglycans, glycoproteins such ...

Alexandrescu, Andrei T.

2005-01-01

212

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

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We 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 fiel...

1988-01-01

213

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

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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

214

Determination of the Oligomer Size of Amyloidogenic Protein ?-Amyloid(1–40) by Single-Molecule Spectroscopy  

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Amyloid diseases are traditionally characterized by the appearance of inter- and intracellular fibrillar protein deposits, termed amyloid. Historically, these deposits have been thought to be the etiology of the disease. However, recent evidence suggests that small oligomers of the amyloidogenic protein/peptide are the origin of neurotoxicity. Although the importance of identifying the toxic oligomeric species is widely recognized, such identification is challenging because these oligomers ar...

Ding, Hao; Wong, Pamela T.; Lee, Edgar L.; Gafni, Ari; Steel, Duncan G.

2009-01-01

215

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

216

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

217

Actions of ?-Amyloid Protein on Human Neurons Are Expressed through the Amylin Receptor  

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Disruption of neurotoxic effects of amyloid ? protein (A?) is one of the major, but as yet elusive, goals in the treatment of Alzheimer's disease (AD). The amylin receptor, activated by a pancreatic polypeptide isolated from diabetic patients, is a putative target for the actions of A? in the brain. Here we show that in primary cultures of human fetal neurons (HFNs), AC253, an amylin receptor antagonist, blocks electrophysiological effects of A?. Pharmacological blockade of the amylin rec...

2011-01-01

218

Mutational analysis of the propensity for amyloid formation by a globular protein  

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Acylphosphatase can be converted in vitro, by addition of trifluoroethanol (TFE), into amyloid fibrils of the type observed in a range of human diseases. The propensity to form fibrils has been investigated for a series of mutants of acylphosphatase by monitoring the range of TFE concentrations that result in aggregation. We have found that the tendency to aggregate correlates inversely with the conformational stability of the native state of the protein in the different mutants. In accord wi...

Chiti, Fabrizio; Taddei, Niccolo?; Bucciantini, Monica; White, Paul; Ramponi, Giampietro; Dobson, Christopher M.

2000-01-01

219

Solvent and mutation effects on the nucleation of amyloid ?-protein folding  

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Experimental evidence suggests that the folding and aggregation of the amyloid ?-protein (A?) into oligomers is a key pathogenetic event in Alzheimer's disease. Inhibiting the pathologic folding and oligomerization of A? could be effective in the prevention and treatment of Alzheimer's disease. Here, using all-atom molecular dynamics simulations in explicit solvent, we probe the initial stages of folding of a decapeptide segment of A?,A?21–30, shown experimentally to nucleate the foldi...

Cruz, Luis; Urbanc, Brigita; Borreguero, Jose M.; Lazo, Noel D.; Teplow, David B.; Stanley, H. Eugene

2005-01-01

220

Amyloid Beta and Tau Proteins as Therapeutic Targets for Alzheimer's Disease Treatment: Rethinking the Current Strategy  

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Alzheimer's disease (AD) is defined by the concurrence of accumulation of abnormal aggregates composed of two proteins: Amyloid beta (A?) and tau, and of cellular changes including neurite degeneration and loss of neurons and cognitive functions. Based on their strong association with disease, genetically and pathologically, it is not surprising that there has been a focus towards developing therapies against the aggregated structures. Unfortunately, current therapies have but mild benefit. ...

Siddhartha Mondragón-Rodríguez; George Perry; Xiongwei Zhu; Jannic Boehm

2012-01-01

 
 
 
 
221

Familial Alzheimer's disease mutations alter the stability of the amyloid ?-protein monomer folding nucleus  

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Amyloid ?-protein (A?) oligomers may be the proximate neurotoxins in Alzheimer's disease (AD). Recently, to elucidate the oligomerization pathway, we studied A? monomer folding and identified a decapeptide segment of A?, 21Ala–22Glu–23Asp–24Val–25Gly–26Ser–27Asn–28Lys–29Gly–30Ala, within which turn formation appears to nucleate monomer folding. The turn is stabilized by hydrophobic interactions between Val-24 and Lys-28 and by long-range electrostatic interactions betwee...

Grant, Marianne A.; Lazo, Noel D.; Lomakin, Aleksey; Condron, Margaret M.; Arai, Hiromi; Yamin, Ghiam; Rigby, Alan C.; Teplow, David B.

2007-01-01

222

Funktion des Amyloid Precursor Proteins und dessen Spaltprodukten bei der synaptischen Übertragung  

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Das Amyloid Precursor Protein (APP) spielt eine wichtige Rolle in der Pathogenese der Alzheimer-Erkrankung. Seine physiologische Funktion in Neuronen, in denen es sich hauptsächlich in den Synapsen befindet, ist immer noch weitestgehend ungeklärt. Mit Hilfe autaptischer, hippocampaler Neurone von APP-Knockout-Mäusen, konnte gezeigt werden, dass Knockout-Neurone signifikant erhöhte Amplituden stimulierter AMPA- und NMDA-Rezeptor vermittelter exzitatorischer postsynaptischer Ströme (EPS...

Priller, Christina

2006-01-01

223

Soluble Beta-Amyloid Precursor Protein Is Related to Disease Progression in Amyotrophic Lateral Sclerosis  

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Background: Biomarkers of disease progression in amyotrophic lateral sclerosis (ALS) could support the identification of beneficial drugs in clinical trials. We aimed to test whether soluble fragments of beta-amyloid precursor protein (sAPPa and sAPP beta) correlated with clinical subtypes of ALS and were of prognostic value.Methodology/Principal Findings: In a cross-sectional study including patients with ALS (N = 68) with clinical follow-up data over 6 months, Parkinson's disease (PD, N = 2...

Steinacker, P.; Fang, L. B.; Kuhle, J.; Petzold, A.; Tumani, H.; Ludolph, A. C.; Otto, M.; Brettschneider, J.

2011-01-01

224

Glutamate system, amyloid ? peptides and tau protein: functional interrelationships and relevance to Alzheimer disease pathology  

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Alzheimer disease is the most prevalent form of dementia globally and is characterized premortem by a gradual memory loss and deterioration of higher cognitive functions and postmortem by neuritic plaques containing amyloid ? peptide and neurofibrillary tangles containing phospho-tau protein. Glutamate is the most abundant neurotransmitter in the brain and is essential to memory formation through processes such as long-term potentiation and so might be pivotal to Alzheimer disease progressio...

Revett, Timothy J.; Baker, Glen B.; Jhamandas, Jack; Kar, Satyabrata

2013-01-01

225

Amyloid precursor protein as a potential marker of malignancy and prognosis in papillary thyroid carcinoma  

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Papillary thyroid carcinoma (PTC) is the most common carcinoma of the thyroid gland and has a relatively favorable prognosis. However, it is important to identify PTC characteristics that indicate a high risk for recurrence and metastasis. Recent data indicate that the amyloid precursor protein (APP) is involved in cell adhesion, motility and proliferation. At present, the expression levels of APP and their prognostic significance in PTC have not been studied. In the present study, the APP ge...

2012-01-01

226

Increased T cell reactivity to amyloid ? protein in older humans and patients with Alzheimer disease  

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Alzheimer disease (AD) is characterized by the progressive deposition of the 42-residue amyloid ? protein (A?) in brain regions serving memory and cognition. In animal models of AD, immunization with A? results in the clearance of A? deposits from the brain. However, a trial of vaccination with synthetic human A?1–42 in AD resulted in the development of meningoencephalitis in some patients. We measured cellular immune responses to A? in middle-aged and elderly healthy subjects and in ...

Monsonego, Alon; Zota, Victor; Karni, Arnon; Krieger, Jeffery I.; Bar-or, Amit; Bitan, Gal; Budson, Andrew E.; Sperling, Reisa; Selkoe, Dennis J.; Weiner, Howard L.

2003-01-01

227

Investigation of amyloid deposition in uterine leiomyoma patients  

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Full Text Available Objects: To investigate the pathogenesis of amyloid presented in uterine leiomyoma. Methods: 36 uterine leiomyoma patients were recruited and divided into two groups according to Congo red staining results. 6 cases are Congo red staining-positive, and 30 cases Congo red staining-negative which represented amyloid positive and amyloid negative respectively. All patients’ serum total protein (TP, albumin (Alb and prealbumin (PA levels were measured as well as blood hemoglobin (Hb, cell counts of white blood cell (WBC, neutrophils (NEU and lymphocyte (LYM. Glycogen in tissue was compared between amyloid accumulated and amyloid negative sections with periodic acid schiff staining (PAS in leiomyoma patients. Results: All of blood Hb concentration, WBC, NEU and LYM have not been found significant differences between two groups. Also no obvious infiltration of inflammatory cells was observed in tissue with amyloid deposition in uterine leiomyoma patients. And levels of TP, Alb and prealbumin have not been found significant differences between two groups. The amyloid was negative in leiomyoma entity cells range by Congo red staining, while small blood vessels in myoma tissues were positively detected with high rate. Amyloid was found in normal tissue around myoma as well as in blood vessel of pseudo-capsule. Increased PAS-positive material induced by leiomyoma was not correlated with amyloid deposition. Conclusions: Metabolic changes in the setting of functional alterations of cell in local microenvironment with uterine leiomyoma, may be related to the amyloid deposition.

Jinping Liu

2012-08-01

228

Human membrane metallo-endopeptidase-like protein degrades both beta-amyloid 42 and beta-amyloid 40.  

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Beta-amyloid (Abeta) degrading endopeptidases are thought to protect against Alzheimer's disease (AD) and are potentially therapeutic. Of particular interest are endopeptidases that are blocked by thiorphan and phosphoramidon (T/P), as these inhibitors rapidly induce Abeta deposition in rodents. Neprilysin (NEP) is the best known target of T/P; however neprilysin knockout results in only modest Abeta increases insufficient to induce deposition. Therefore, other endopeptidases targeted by T/P must be critical for Abeta catabolism. Another candidate is the T/P sensitive membrane metallo-endopeptidase-like protein (MMEL), a close homolog of neprilysin. The endopeptidase properties of beta and gamma splice forms of human MMEL were determined in HEK293T cells transduced with the human cDNAs for the two splice forms; this showed degradation of both Abeta(42) and Abeta(40) by hMMEL-beta but not hMMEL-gamma. hMMEL-beta activity was found at the extracellular surface with no significant secreted activity. hMMEL-gamma was not expressed at the extracellular surface. Finally, it was found that hMMEL cleaves Abeta near the alpha-secretase site (producing Abeta(1-17)>Abeta(1-16)). These data establish hMMEL as a mediator of Abeta catabolism and raise the possibility of its involvement in the etiology of AD and as a target for intervention. PMID:18571334

Huang, J Y; Bruno, A M; Patel, C A; Huynh, A M; Philibert, K D; Glucksman, M J; Marr, R A

2008-07-31

229

Immunohistochemical localization of 14.3.3 zeta protein in amyloid plaques in human spongiform encephalopathies.  

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The localization of 14.3.3 proteins was studied in different subtypes of brain amyloid plaques. We examined paraffin-embedded brain sections of sporadic MV2 Creutzfeldt-Jakob disease (sCJD) with Kuru plaques, sporadic VV2 CJD with plaque-like PrP(sc) (the abnornal form of prion protein) deposits, variant CJD (vCJD) with florid plaques, Gerstmann-Straüssler-Scheinker (GSS) with multicentric plaques and of Alzheimer's disease (AD) with senile plaques. Adjacent immunostaining revealed PrP(sc) and 14.3.3 zeta deposits in the same amyloid plaques in all cases of sporadic CJD and vCJD, whereas 14.3.3 zeta was not seen in amyloid plaques of GSS with A117V, P102L and D202N mutations. The same immunostaining method using anti-betaA4 and anti-14.3.3 zeta antibodies revealed no colocalization in patients with AD. Our data suggest that 14.3.3 zeta protein could interact either with PrP or with other components of PrP(sc) deposits in CJD. PMID:12557018

Richard, Marlène; Biacabe, Anne-Gaëlle; Streichenberger, Nathalie; Ironside, James West; Mohr, Michel; Kopp, Nicolas; Perret-Liaudet, Armand

2003-03-01

230

Assessment of Oritavancin Serum Protein Binding across Species?  

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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

231

Sorting by the Cytoplasmic Domain of the Amyloid Precursor Protein Binding Receptor SorLA? †  

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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 A?-peptide. The receptor is mainly located in vesicles, suggesting a function in protein sortin...

Nielsen, Morten S.; Gustafsen, Camilla; Madsen, Peder; Nyengaard, Jens R.; Hermey, Guido; Bakke, Oddmund; Mari, Muriel; Schu, Peter; Pohlmann, Regina; Dennes, Andre?; Petersen, Claus M.

2007-01-01

232

Unraveling the Early Events of Amyloid-? Protein (A? Aggregation: Techniques for the Determination of A? Aggregate Size  

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Full Text Available The aggregation of proteins into insoluble amyloid fibrils coincides with the onset of numerous diseases. An array of techniques is available to study the different stages of the amyloid aggregation process. Recently, emphasis has been placed upon the analysis of oligomeric amyloid species, which have been hypothesized to play a key role in disease progression. This paper reviews techniques utilized to study aggregation of the amyloid-? protein (A? associated with Alzheimer’s disease. In particular, the review focuses on techniques that provide information about the size or quantity of oligomeric A? species formed during the early stages of aggregation, including native-PAGE, SDS-PAGE, Western blotting, capillary electrophoresis, mass spectrometry, fluorescence correlation spectroscopy, light scattering, size exclusion chromatography, centrifugation, enzyme-linked immunosorbent assay, and dot blotting.

N. Elizabeth Pryor

2012-03-01

233

Comparable dimerization found in wildtype and familial Alzheimer's disease amyloid precursor protein mutants.  

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Alzheimer's disease (AD) is a progressive and fatal neurodegenerative disorder marked by memory impairment and cognitive deficits. A major component of AD pathology is the accumulation of amyloid plaques in the brain, which are comprised of amyloid beta (A?) peptides derived from the amyloidogenic processing of the amyloid precursor protein (A?PP) by ?- and ?-secretases. In a subset of patients, inheritance of mutations in the A?PP gene is responsible for altering A? production, leading to early onset disease. Interestingly, many of these familial mutations lie within the transmembrane domain of the protein near the GxxxG and GxxxA dimerization motifs that are important for transmembrane interactions. As A?PP dimerization has been linked to changes in A? production, it is of interest to know whether familial A?PP mutations affect full-length APP dimerization. Using bimolecular fluorescence complementation (BiFC), blue native gel electrophoresis, and live cell chemical cross-linking, we found that familial Alzheimer's disease (FAD) mutations do not affect full-length A?PP dimerization in transfected HEK293 and COS7 cells. It follows that changes in A?PP dimerization are not necessary for altered A? production, and in FAD mutations, changes in A? levels are more likely a result of alternative proteolytic processing. PMID:23515184

So, Pauline Pl; Khodr, Christina E; Chen, Ci-Di; Abraham, Carmela R

2013-01-01

234

Spontaneous and BSE-prion-seeded amyloid formation of full length recombinant bovine prion protein.  

Science.gov (United States)

The conversion of the cellular isoform of the prion protein into the pathogenic isoform PrP(Sc) is the key event in prion diseases. The disease can occur spontaneously genetically or by infection. In earlier studies we presented an in vitro conversion system which simulates the structural transition in recPrP by varying low concentrations of SDS at constant NaCl. In the present study we adopted the conversion system from experimental Scrapie in hamster to bovine recPrP and generated amyloid fibrils. The intermediate state which is optimal for fibril formation is a soluble, beta-rich state. The system was extended using BSE-prions as seeds and led to an acceleration of fibril formation by orders of magnitude. This seeded amyloid formation assay avoids any PK-treatment, is therefore able to detect even PK-sensitive PrP(Sc) and does not require cellular components. PMID:18585368

Panza, Giannantonio; Stöhr, Jan; Dumpitak, Christian; Papathanassiou, Dimitrios; Weiss, Jürgen; Riesner, Detlev; Willbold, Dieter; Birkmann, Eva

2008-09-01

235

A critical assessment of the role of helical intermediates in amyloid formation by natively unfolded proteins and polypeptides  

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Amyloidogenic proteins and polypeptides can be divided into two structural classes, namely those which are flexible and are intrinsically disordered in their unaggregated state and those which form a compact globular structure with a well-defined tertiary fold in their normally soluble state. This review article is focused on amyloid formation by natively disordered polypeptides. Important examples of this class include islet amyloid polypeptide (IAPP, amylin), pro-IAPP processing intermediat...

Abedini, Andisheh; Raleigh, Daniel P.

2009-01-01

236

Presenilin-dependent ?-secretase processing of ?-amyloid precursor protein at a site corresponding to the S3 cleavage of Notch  

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The presenilin (PS)-dependent site 3 (S3) cleavage of Notch liberates its intracellular domain (NICD), which is required for Notch signaling. The similar ?-secretase cleavage of the ?-amyloid precursor protein (?APP) results in the secretion of amyloid ?-peptide (A?). However, little is known about the corresponding C-terminal cleavage product (CTF?). We have now identified CTF? in brain tissue, in living cells, as well as in an in vitro system. Generation of CTF? is facilitated by PS...

Sastre, Magdalena; Steiner, Harald; Fuchs, Klaus; Capell, Anja; Multhaup, Gerd; Condron, Margaret M.; Teplow, David B.; Haass, Christian

2001-01-01

237

Amyloid-? protein oligomerization and the importance of tetramers and dodecamers in the aetiology of Alzheimer’s disease  

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In recent years, small protein oligomers have been implicated in the aetiology of a number of important amyloid diseases, such as type 2 diabetes, Parkinson’s disease and Alzheimer’s disease. As a consequence, research efforts are being directed away from traditional targets, such as amyloid plaques, and towards characterization of early oligomer states. Here we present a new analysis method, ion mobility coupled with mass spectrometry, for this challenging problem, which allows determina...

Bernstein, Summer L.; Dupuis, Nicholas F.; Lazo, Noel D.; Wyttenbach, Thomas; Condron, Margaret M.; Bitan, Gal; Teplow, David B.; Shea, Joan-emma; Ruotolo, Brandon T.; Robinson, Carol V.; Bowers, Michael T.

2009-01-01

238

Large Quantities of A? Peptide Are Constitutively Released during Amyloid Precursor Protein Metabolism in Vivo and in Vitro*  

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The metabolism of the amyloid precursor protein (APP) has been extensively investigated because its processing generates the amyloid-?-peptide (A?), which is a likely cause of Alzheimer disease. Much prior research has focused on APP processing using transgenic constructs and heterologous cell lines. Work to date in native neuronal cultures suggests that A? is produced in very large amounts. We sought to investigate APP metabolism and A? production simultaneously under more physiological ...

2011-01-01

239

Serum amyloid A concentrations in giant-cell arteritis and polymyalgia rheumatica: a useful test in the management of the disease.  

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A prospective clinical study of 23 patients with giant-cell arteritis (GCA) and/or polymyalgia rheumatica (PMR) was undertaken in order to assess the behaviour of the non-specific markers of the disease activity, the erythrocyte sedimentation rate (ESR) and other acute phase markers, particularly the C-reactive protein (CPR) and serum amyloid A apolipoprotein (apo SAA) levels during induction of disease remission by prednisone therapy, and possible further recurrence of GCA and/or PMR. The apo SAA measurement is more sensitive than the CRP measurement in determining disease activity (97% and 61%, respectively). The specificity of apo SAA is greater than ESR in the determination of inactive disease (86% and 77%, respectively). In some cases with clinically active disease the ESR and CRP were normal, whereas the apo SAA was always elevated. We conclude that the apo SAA measurement in combination with clinical data and other laboratory parameters may be useful in the management of GCA and/or PMR. PMID:1711943

Hachulla, E; Saile, R; Parra, H J; Hatron, P Y; Gosset, D; Fruchart, J C; Devulder, B

1991-01-01

240

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

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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

 
 
 
 
241

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

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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

242

Origins and Evolution of the HET-s Prion-Forming Protein: Searching for Other Amyloid-Forming Solenoids  

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The HET-s prion-forming domain from the filamentous fungus Podospora anserina is gaining considerable interest since it yielded the first well-defined atomic structure of a functional amyloid fibril. This structure has been identified as a left-handed beta solenoid with a triangular hydrophobic core. To delineate the origins of the HET-s prion-forming protein and to discover other amyloid-forming proteins, we searched for all homologs of the HET-s protein in a database of protein domains and ...

Gendoo, Deena M. A.; Harrison, Paul M.

2011-01-01

243

Cerebrospinal fluid amyloid beta and tau protein: Biomarkers for Alzheimer's disease  

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Background/Aim. Introduction of acetylcholine esterase inhibitors as a symptomatic treatment of Alzheimer's disease (AD) has additionally highlighted the importance of diagnostic markers in cerebrospinal fluid (CSF) for early AD diagnosis: low level of 42 amino acid form of amyloid-? peptide (A?42), and levels of tau protein (T-tau) and phosphorylated tau protein (P-tau). The aim of this study was to diagnostic potential of CSF biomarkers T-tau, P-tau and A?42 as biochemical markers for AD...

Mandi? Gorana; Markovi? Ivanka; Ostoji? Marija; Stojkovi? Tanja; Misirli?-Den?i? Sonja; Živanovi?-Radni? Tatjana; Stefanovi? Rodoljub; Bumbaširevi? Marko; Stefanova Elka; Kosti? Vladimir

2008-01-01

244

MicroRNA-384 regulates both amyloid precursor protein and ?-secretase expression and is a potential biomarker for Alzheimer's disease.  

Science.gov (United States)

Amyloid precursor protein (APP) and ?-site APP cleaving enzyme (BACE-1) play important roles in the pathogenesis of Alzheimer's disease (AD). In this study, using bioinformatics analysis, we demonstrate that miR-384 is a microRNA (miRNA or miR) predicted to potentially target the 3' untranslated regions (3'-UTRs) of both APP and BACE-1. SH-SY5Y cells were transfected with miR-384 mimic oligonucleotide, miR-384 inhibitor oligonucleotide, or a non-specific control siRNA. We found that the overexpression of miR-384 suppressed the mRNA and protein expression of both APP and BACE-1. The miR-384 inhibitor oligonucleotide induced the upregulation of APP and BACE-1. The activity of BACE-1 was altered following the change in its protein expression. The binding sites of miR-384 on the 3'-UTRs of APP and BACE-1 were identified by luciferase assay. Furthermore, cells were treasted with amyloid-? (A?)42. A?42 downregulated miR-384 expression, leading to the continuous reduction in miR-384 expression. In addition, using a mouse model of AD, as well as patients with mild cognitive impairment (MCI) and dementia of Alzheimer's type (DAT), we examined the levels of miR-384 in cerebral spinal fluid (CSF) and serum. Patients with MCI and DAT had lower blood miR-384 levels compared with the controls. In addition, patients with DAT had lower blood miR-384 levels in blood compared with the MCI group. We also found decreased miR-384 expression in the several cerebral spinal fluid (CSF) of the patients with DAT. Negative correlations were observed between miR-384 and A?42 in the serum and CSF from patients with AD. In conclusion, these findings demonstrate that miR-384 may plays a role in the development of AD and may be a potential non-invasive biomarker for the diagnosis of AD. PMID:24827165

Liu, Chen-Geng; Wang, Jin-Ling; Li, Lei; Wang, Pei-Chang

2014-07-01

245

Use of subcutaneous abdominal fat biopsy specimen for detailed typing of amyloid fibril protein-AL by amino acid sequence analysis.  

Science.gov (United States)

A simple technique for the purification of amyloid fibril proteins from patients with systemic amyloidosis was used on a 45 year old woman. The method is based on the use of a surgical subcutaneous fat tissue biopsy specimen which was used for the characterisation of the amyloid as a kappa I AL-protein by amino acid sequence analysis. The method permits the exact typing of amyloid in many patients with systemic amyloidosis, which, until now has been almost exclusively confined to necropsy tissue.

Westermark, P; Benson, L; Juul, J; Sletten, K

1989-01-01

246

The low density lipoprotein receptor-related protein 1B retains beta-amyloid precursor protein at the cell surface and reduces amyloid-beta peptide production.  

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The low density lipoprotein (LDL) receptor-related protein 1B (LRP1B) is a newly identified member of the LDL receptor family that shares high homology with the LDL receptor-related protein (LRP). LRP1B was originally described as a putative tumor suppressor in lung cancer cells; however, its expression profile in several regions of adult human brain suggests it may have additional functions in the central nervous system. Since LRP1B has overlapping ligand binding properties with LRP, we investigated whether LRP1B, like LRP, could interact with the beta-amyloid precursor protein (APP) and modulate its processing to amyloid-beta peptides (Abetas). Using an LRP1B minireceptor (mLRP1B4) generated to study the trafficking of LRP1B, we found that mLRP1B4 and APP form an immunoprecipitable complex. Furthermore mLRP1B4 bound and facilitated the degradation of a soluble isoform of APP containing a Kunitz proteinase inhibitor domain but not soluble APP lacking a Kunitz proteinase inhibitor domain. A functional consequence of mLRP1B4 expression was a significant accumulation of APP at the cell surface, which is likely related to the slow endocytosis rate of LRP1B. More importantly, mLRP1B4-expressing cells that accumulated cell surface APP produced less Abeta and secreted more soluble APP. These findings reveal that LRP1B is a novel binding partner of APP that functions to decrease APP processing to Abeta. Consequently LRP1B expression could function to protect against the pathogenesis of Alzheimer's disease. PMID:15126508

Cam, Judy A; Zerbinatti, Celina V; Knisely, Jane M; Hecimovic, Silva; Li, Yonghe; Bu, Guojun

2004-07-01

247

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)

1982-01-01

248

Specific spatial learning deficits become severe with age in ?-amyloid precursor protein transgenic mice that harbor diffuse ?-amyloid deposits but do not form plaques  

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Memory impairment progressing to dementia is the main clinical symptom of Alzheimer's disease (AD). AD is characterized histologically by the presence of ?-amyloid (A?) plaques and neurofibrillary tangles in specific brain regions. Although A? derived from the A? precursor protein (?-APP) is believed to play a central etiological role in AD, it is not clear whether soluble and/or fibrillar forms are responsible for the memory deficit. We have generated and pre...

Koistinaho, Milla; Ort, Michael; Cimadevilla, Jose M.; Vondrous, Roman; Cordell, Barbara; Koistinaho, Jari; Bures, Jan; Higgins, Linda S.

2001-01-01

249

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.

Matthew R. Chapman

2013-02-01

250

Serum total proteins and serum total cholesterol levels in Gaolao Cattle  

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The healthy female Gaolao cattle were selected and divided in three groups of ten animals each with reference to age. The blood samples were processed for clear serum collection and estimation of serum total proteins, albumin, globulin, albumin and globulin ratio and serum total cholesterol. It is reported that female calves had low total proteins, albumin and globulin than the adult cows. [Veterinary World 2008; 1(4.000): 115-116

2008-01-01

251

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

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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

252

Electrostatics Controls the Formation of Amyloid Superstructures in Protein Aggregation  

Science.gov (United States)

The possibility for proteins to aggregate in different superstructures, i.e. large-scale polymorphism, has been widely observed, but an understanding of the physicochemical mechanisms behind it is still out of reach. Here we present a theoretical model for the description of a generic aggregate formed from an ensemble of charged proteins. The model predicts the formation of multifractal structures with the geometry of the growth determined by the electrostatic interactions between single proteins. The model predictions are successfully verified in comparison with experimental curves for aggregate growth allowing us to reveal the mechanism of formation of such complex structures. The model is general and is able to predict aggregate morphologies occurring both in vivo and in vitro. Our findings provide a framework where the physical interactions between single proteins, the aggregate morphology, and the growth kinetics are connected into a single model in agreement with the experimental data.

Foderà, Vito; Zaccone, Alessio; Lattuada, Marco; Donald, Athene M.

2013-09-01

253

AMYPdb: a database dedicated to amyloid precursor proteins.  

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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 ...

Pawlicki, Sandrine; Le Be?chec, Antony; Delamarche, Christian

2008-01-01

254

Changes of serum proteins in standardization of genetic serum protein polymorphisms after UV irradiation of serum samples  

International Nuclear Information System (INIS)

After short-term irradiation of fresh serum samples with ultraviolet light (UVC; 1 to 10 minutes) partly distinct changes were observed spectrophotometrically in the differential spectrum and by electrophoresis and isoelectrofocusing; resp. The protein bands of the systems Bf, C3, Tf, Hp and Gc were attenuated up to vanishing. In the Pi system trifling changes of the isoelectric point with a simulation of 'new' phenotypes could be produced. (author)

1987-01-01

255

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

256

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

2013-03-29

257

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

258

Heat shock alters Alzheimer's beta amyloid precursor protein expression in human endothelial cells.  

Science.gov (United States)

One of the pathological lesions in Alzheimer's disease (AD) is the amyloid or senile plaque. The plaque core is predominantly made up of amyloid beta peptide (A beta), a 42-43 amino acid peptide derived from amyloid precursor protein (APP). APP is a membrane bound glycoprotein which is expressed ubiquitously in many cells. Although normal or pathological functions for APP are not well understood, several observations suggest that APP may play a role in cellular stress and inflammation at the endothelial cell/vascular barrier. APP is found in platelets and endothelial cells, it can inhibit a blood coagulation factor, and secreted APP can be neuroprotective. Changes in expression of APP during cellular stress or inflammation may contribute to pathological deposition of A beta. In the present studies, expression of APP in human endothelial cells was examined following heat shock. In human umbilical vein endothelial cells (HUVECs) exposed to 42 degrees C for 30 min, there was a five- to eight-fold increase in APP mRNA levels which peaked at 4 hr. The increase in APP mRNA was followed by an increase in APP protein immunoreactivity in the cytoplasm in a perinuclear Golgi-like region, and in discrete granular cytoplasmic structures. Immunoblot analysis of APP in the cell media found a transient increase in APP which peaked at 1 hr after heat shock. These results suggest that cellular stress induces the secretion of APP from endothelial cells followed by a subsequent increase in APP mRNA and protein synthesis. The upregulation of APP mRNA and protein supports a cellular stress role for APP. PMID:8046777

Ciallella, J R; Rangnekar, V V; McGillis, J P

1994-04-15

259

An accessory protein required for anchoring and assembly of amyloid fibres in B. subtilis biofilms.  

Science.gov (United States)

Cells within Bacillus subtilis biofilms are held in place by an extracellular matrix that contains cell-anchored amyloid fibres, composed of the amyloidogenic protein TasA. As biofilms age they disassemble because the cells release the amyloid fibres. 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; previously YqxM) that serves both to anchor the fibres to the cell wall and to assemble TasA into fibres. TapA is found in discrete foci in the cell envelope and these foci disappear when cells are treated with a mixture of D-amino acids. Purified cell wall sacculi retain a functional form of this anchoring protein such that purified fibres can be anchored to the sacculi in vitro. In addition, we show that TapA is essential for the proper assembly of the fibres. Its absence results in a dramatic reduction in TasA levels and what little TasA is left produces only thin fibres that are not anchored to the cell. PMID:21477127

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

2011-06-01

260

Alzheimer Amyloid-? Oligomer Bound to Post-Synaptic Prion Protein Activates Fyn to Impair Neurons  

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Amyloid-beta (A?) oligomers are thought to trigger Alzheimer’s disease (AD) pathophysiology. Cellular Prion Protein (PrPC) selectively binds oligomeric A? and can mediate AD-related phenotypes. Here, we examined the specificity, distribution and signaling from A?/PrP complexes, seeking to explain how they might alter the function of NMDA receptors in neurons. PrPC is enriched in post-synaptic densities, and A?/PrPC interaction leads to Fyn kinase activation. Soluble A? assemblies deriv...

Um, Ji Won; Nygaard, Haakon B.; Heiss, Jacqueline K.; Kostylev, Mikhail A.; Stagi, Massimiliano; Vortmeyer, Alexander; Wisniewski, Thomas; Gunther, Erik C.; Strittmatter, Stephen M.

2012-01-01

 
 
 
 
261

The Amyloid ?-Protein: Experiment and Theory on the 21-30 Fragment  

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The structure of the 21-30 fragment of the amyloid ?-protein (A?) was investigated by ion-mobility mass spectrometry and replica exchange dynamics simulations. Mutations associated with familial Alzheimer’s disease (E22G, E22Q, E22K, and D23N) of A?(21-30) were also studied, in order to understand any structural changes that might occur with these substitutions. The structure of the WT peptide shows a bend and a perpendicular turn in the backbone which is maintained by a network of D23 h...

Murray, Megan M.; Krone, Mary Griffin; Bernstein, Summer L.; Baumketner, Andrij; Condron, Margaret M.; Lazo, Noel D.; Teplow, David B.; Wyttenbach, Thomas; Shea, Joan-emma; Bowers, Michael T.

2009-01-01

262

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

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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

263

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.)

1984-01-01

264

Thrombin induces surface and intracellular secretion of amyloid precursor protein from human endothelial cells.  

Science.gov (United States)

Thrombin, a major coagulant and inflammatory mediator, was shown to regulate amyloid precursor protein (APP) secretion. APP is the protein from which the amyloid beta peptide (A(beta)) is derived. A(beta) forms the core of vascular and cerebral plaques in Alzheimer's disease (AD). In this study, human umbilical vein endothelial cells (HUVEC) were used to examine the effects of thrombin on APP expression. Cell supernatants from thrombin-treated HUVEC were immunoblotted to measure secreted APP. Thrombin-induced secretion of APP peaks at approximately 30 min post-treatment. Immunohistochemical analysis found that APP is not colocalized with or secreted through the same pathway as coagulation factor VIII. The secretion of APP is thrombin receptor-mediated, since it is inhibited by the thrombin antagonist N-Acetyl-D-Phe-Pro-1-Amido-4-Guanidino-Butyl-1-Boronic Acid. It also is induced by treatment with a calcium ionophore. Moreover, APP secretion is protein kinase C (PKC)-dependent because it is blocked by the PKC inhibitor bisindolylmaleimide. APP secretion also occurs from the cell surface, possibly through direct cleavage by thrombin. Immunoreactivity on the surface of HUVEC decreased after thrombin treatment but not after treatment with a non-proteolytic thrombin receptor activator. These data suggest that thrombin induces APP secretion through a PKC-dependent mechanism, as well as from the cell surface. Our results are consistent with thrombin playing a role in AD pathology. PMID:10235452

Ciallella, J R; Figueiredo, H; Smith-Swintosky, V; McGillis, J P

1999-04-01

265

Interaction between Prion Protein and A? Amyloid Fibrils Revisited.  

Science.gov (United States)

Recent studies indicate that the pathogenesis of Alzheimer disease may be related to the interaction between prion protein (PrP) and certain oligomeric species of A? peptide. However, the mechanism of this interaction remains unclear and controversial. Here we provide direct experimental evidence that, in addition to previously demonstrated binding to A? oligomers, PrP also interacts with mature A? fibrils. However, contrary to the recent claim that PrP causes fragmentation of A? fibrils into oligomeric species, no evidence for such a disassembly could be detected in the present study. In contrast, our data indicate that the addition of PrP to preformed A? fibrils results in a lateral association of individual fibrils into larger bundles. These findings have potentially important implications for understanding the mechanism by which PrP might impact A? toxicity as well as for the emerging efforts to use PrP-derived compounds as inhibitors of A?-induced neurodegeneration. PMID:24669873

Nieznanski, Krzysztof; Surewicz, Krystyna; Chen, Shugui; Nieznanska, Hanna; Surewicz, Witold K

2014-05-21

266

Alzheimer disease A68 proteins injected into rat brain induce codeposits of beta-amyloid, ubiquitin, and alpha 1-antichymotrypsin.  

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Aberrantly phosphorylated tau proteins (i.e., A68 or PHF-tau) and beta-amyloid or A4 (beta A4) peptides are major components of pathologic lesions in Alzheimer disease (AD). Although A68 and beta A4 colocalize in AD neurofibrillary tangles (NFTs) and amyloid-rich senile plaques (SPs), the mechanisms leading to the convergence of A68, beta A4, and other proteins in the same AD lesions are unknown. To probe the biological properties of A68 in vivo, and to assess interactions of A68 with endogen...

Shin, R. W.; Bramblett, G. T.; Lee, V. M.; Trojanowski, J. Q.

1993-01-01

267

Ceruloplasmin and ?-amyloid precursor protein confer neuroprotection in traumatic brain injury and lower neuronal iron.  

Science.gov (United States)

Traumatic brain injury (TBI) is in part complicated by pro-oxidant iron elevation independent of brain hemorrhage. Ceruloplasmin (CP) and ?-amyloid protein precursor (APP) are known neuroprotective proteins that reduce oxidative damage through iron regulation. We surveyed iron, CP, and APP in brain tissue from control and TBI-affected patients who were stratified according to time of death following injury. We observed CP and APP induction after TBI accompanying iron accumulation. Elevated APP and CP expression was also observed in a mouse model of focal cortical contusion injury concomitant with iron elevation. To determine if changes in APP or CP were neuroprotective we employed the same TBI model on APP(-/-) and CP(-/-) mice and found that both exhibited exaggerated infarct volume and iron accumulation postinjury. Evidence supports a regulatory role of both proteins in defence against iron-induced oxidative damage after TBI, which presents as a tractable therapeutic target. PMID:24509156

Ayton, Scott; Zhang, Moses; Roberts, Blaine R; Lam, Linh Q; Lind, Monica; McLean, Catriona; Bush, Ashley I; Frugier, Tony; Crack, Peter J; Duce, James A

2014-04-01

268

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.

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

2014-01-01

269

Mechanism of amyloid ?-protein dimerization determined using single-molecule AFM force spectroscopy.  

Science.gov (United States)

A?42 and A?40 are the two primary alloforms of human amyloid ?-protein (A?). The two additional C-terminal residues of A?42 result in elevated neurotoxicity compared with A?40, but the molecular mechanism underlying this effect remains unclear. Here, we used single-molecule force microscopy to characterize interpeptide interactions for A?42 and A?40 and corresponding mutants. We discovered a dramatic difference in the interaction patterns of A?42 and A?40 monomers within dimers. Although the sequence difference between the two peptides is at the C-termini, the N-terminal segment plays a key role in the peptide interaction in the dimers. This is an unexpected finding as N-terminal was considered as disordered segment with no effect on the A? peptide aggregation. These novel properties of A? proteins suggests that the stabilization of N-terminal interactions is a switch in redirecting of amyloids form the neurotoxic aggregation pathway, opening a novel avenue for the disease preventions and treatments. PMID:24096987

Lv, Zhengjian; Roychaudhuri, Robin; Condron, Margaret M; Teplow, David B; Lyubchenko, Yuri L

2013-01-01

270

Mechanism of amyloid ?-protein dimerization determined using single-molecule AFM force spectroscopy  

Science.gov (United States)

A?42 and A?40 are the two primary alloforms of human amyloid ??protein (A?). The two additional C?terminal residues of A?42 result in elevated neurotoxicity compared with A?40, but the molecular mechanism underlying this effect remains unclear. Here, we used single?molecule force microscopy to characterize interpeptide interactions for A?42 and A?40 and corresponding mutants. We discovered a dramatic difference in the interaction patterns of A?42 and A?40 monomers within dimers. Although the sequence difference between the two peptides is at the C?termini, the N?terminal segment plays a key role in the peptide interaction in the dimers. This is an unexpected finding as N?terminal was considered as disordered segment with no effect on the A? peptide aggregation. These novel properties of A? proteins suggests that the stabilization of N?terminal interactions is a switch in redirecting of amyloids form the neurotoxic aggregation pathway, opening a novel avenue for the disease preventions and treatments.

Lv, Zhengjian; Roychaudhuri, Robin; Condron, Margaret M.; Teplow, David B.; Lyubchenko, Yuri L.

2013-01-01

271

Mechanism of amyloid ?-protein dimerization determined using single-molecule AFM force spectroscopy  

Science.gov (United States)

A?42 and A?40 are the two primary alloforms of human amyloid ?-protein (A?). The two additional C-terminal residues of A?42 result in elevated neurotoxicity compared with A?40, but the molecular mechanism underlying this effect remains unclear. Here, we used single-molecule force microscopy to characterize interpeptide interactions for A?42 and A?40 and corresponding mutants. We discovered a dramatic difference in the interaction patterns of A?42 and A?40 monomers within dimers. Although the sequence difference between the two peptides is at the C-termini, the N-terminal segment plays a key role in the peptide interaction in the dimers. This is an unexpected finding as N-terminal was considered as disordered segment with no effect on the A? peptide aggregation. These novel properties of A? proteins suggests that the stabilization of N-terminal interactions is a switch in redirecting of amyloids form the neurotoxic aggregation pathway, opening a novel avenue for the disease preventions and treatments.

Lv, Zhengjian; Roychaudhuri, Robin; Condron, Margaret M.; Teplow, David B.; Lyubchenko, Yuri L.

2013-10-01

272

Modulation of ?-amyloid precursor protein trafficking and processing by the low density lipoprotein receptor family  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Amyloid-? peptide (A? accumulation in the brain is an early, toxic event in the pathogenesis of Alzheimer's disease (AD. A? is produced by proteolytic processing of a transmembrane protein, ?-amyloid precursor protein (APP, by ?- and ?-secretases. Mounting evidence has demonstrated that alterations in APP cellular trafficking and localization directly impact its processing to A?. Recent studies have shown that members of the low-density lipoprotein receptor family, including LRP, LRP1B, SorLA/LR11, and apolipoprotein E (apoE receptor 2, interact with APP and regulate its endocytic trafficking. Another common feature of these receptors is their ability to bind apoE, which exists in three isoforms in humans and the presence of the ?4 allele represents a genetic risk factor for AD. In this review, we summarize the current understanding of the function of these apoE receptors with a focus on their role in APP trafficking and processing. Knowledge of the interactions between these distinct low-density lipoprotein receptor family members and APP may ultimately influence future therapies for AD.

Cam Judy A

2006-08-01

273

Photochemistry of modified proteins benzophenone-containing bovine serum albumin  

International Nuclear Information System (INIS)

The results of exploratory and mechanistic studies of the photochemistry of poly-p-benzoyl-acetimido-bovine serum albumin, a modified protein containing photoreactive and photosensitizing groups, are reported. Specifically described are recent findings concerning (1) the synthesis and characterization of a modified bovine serum albumin that contains benzophenone-like moieties, (2) the photochemistry of this modified protein which appeared to involve photoreductive coupling of the benzophenone chromophores to the protein backbone, and (3) triplet energy transfer from modified bovine serum albumin to small molecule acceptors resulting in quenching of the photoreaction. (author)

1976-01-01

274

Amyloid precursor proteins are protective in Drosophila models of progressive neurodegeneration.  

Science.gov (United States)

The processing of Amyloid Precursor Proteins (APPs) results in several fragments, including soluble N-terminal ectodomains (sAPPs) and C-terminal intracellular domains (AICD). sAPPs have been ascribed neurotrophic or neuroprotective functions in cell culture, although ?-cleaved sAPPs can have deleterious effects and trigger neuronal cell death. Here we describe a neuroproprotective function of APP and fly APPL (Amyloid Precursor Protein-like) in vivo in several Drosophila mutants with progressive neurodegeneration. We show that expression of the N-terminal ectodomain is sufficient to suppress the progressive degeneration in these mutants and that the secretion of the ectodomain is required for this function. In addition, a protective effect is achieved by expressing kuzbanian (which has ?-secretase activity) whereas expression of fly and human BACE aggravates the phenotypes, suggesting that the protective function is specifically mediated by the ?-cleaved ectodomain. Furthermore, genetic and molecular studies suggest that the N-terminal fragments interact with full-length APPL activating a downstream signaling pathway via the AICD. Because we show protective effects in mutants that affect different genes (AMP-activated protein kinase, MAP1b, rasGAP), we propose that the protective effect is not due to a genetic interaction between APPL and these genes but a more general aspect of APP proteins. The result that APP proteins and specifically their soluble ?-cleaved ectodomains can protect against progressive neurodegeneration in vivo provides support for the hypothesis that a disruption of the physiological function of APP could play a role in the pathogenesis of Alzheimer's Disease. PMID:22266106

Wentzell, Jill S; Bolkan, Bonnie J; Carmine-Simmen, Katia; Swanson, Tracy L; Musashe, Derek T; Kretzschmar, Doris

2012-04-01

275

Conformational dynamics of amyloid beta-protein assembly probed using intrinsic fluorescence.  

Science.gov (United States)

Formation of toxic oligomeric and fibrillar structures by the amyloid beta-protein (Abeta) is linked to Alzheimer's disease (AD). To facilitate the targeting and design of assembly inhibitors, intrinsic fluorescence was used to probe assembly-dependent changes in Abeta conformation. To do so, Tyr was substituted in Abeta40 or Abeta42 at position 1, 10 (wild type), 20, 30, 40, or 42. Fluorescence then was monitored periodically during peptide monomer folding and assembly. Electron microscopy revealed that all peptides assembled readily into amyloid fibrils. Conformational differences between Abeta40 and Abeta42 were observed in the central hydrophobic cluster (CHC) region, Leu17-Ala21. Tyr20 was partially quenched in unassembled Abeta40 but displayed a significant and rapid increase in intensity coincident with the maturation of an oligomeric, alpha-helix-containing intermediate into amyloid fibrils. This process was not observed during Abeta42 assembly, during which small decreases in fluorescence intensity were observed in the CHC. These data suggest that the structure of the CHC in Abeta42 is relatively constant within unassembled peptide and during the self-association process. Solvent accessibility of the Tyr ring was studied using a mixed solvent (dimethyl sulfoxide/water) system. [Tyr40]Abeta40, [Tyr30]Abeta42, and [Tyr42]Abeta42 all were relatively shielded from solvent. Analysis of the assembly dependence of the site-specific intrinsic fluorescence data suggests that the CHC is particularly important in controlling Abeta40 assembly, whereas the C-terminus plays the more significant role in Abeta42 assembly. PMID:16201761

Maji, Samir K; Amsden, Jason J; Rothschild, Kenneth J; Condron, Margaret M; Teplow, David B

2005-10-11

276

Cerebrospinal Fluid from Alzheimer's disease patients promotes amyloid beta-protein oligomerization.  

Science.gov (United States)

Oligomers of the amyloid beta-protein (Abeta) play an important role in Alzheimer's disease (AD). We hypothesized that AD patients have a central nervous system environment that promotes Abeta oligomerization. We investigated the effect of cerebrospinal fluid (CSF) from 33 patients with AD and 33 age-matched, non-demented controls on oligomerization of Abeta1-40 and Abeta1-42 using the technique of photo-induced cross-linking of unmodified proteins. CSF inhibited oligomerization of both Abeta1-40 and Abeta1-42. This inhibitory effect was significantly weaker in AD patients than in non-demented controls. Our results indicate that AD patients have a CSF environment favorable for Abeta oligomerization. PMID:20413863

Ikeda, Tokuhei; Ono, Kenjiro; Elashoff, David; Condron, Margaret M; Noguchi-Shinohara, Moeko; Yoshita, Mitsuhiro; Teplow, David B; Yamada, Masahito

2010-01-01

277

Recombinant immunoglobulin variable domains generated from synthetic genes provide a system for in vitro characterization of light-chain amyloid proteins.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The primary structural features that render human monoclonal light chains amyloidogenic are presently unknown. To gain further insight into the physical and biochemical factors that result in the pathologic deposition of these proteins as amyloid fibrils, we have selected for detailed study three closely homologous protein products of the light-chain variable-region single-gene family VkIV. Two of these proteins, REC and SMA, formed amyloid fibrils in vivo. The third protein, LEN, was excrete...

Stevens, P. W.; Raffen, R.; Hanson, D. K.; Deng, Y. L.; Berrios-hammond, M.; Westholm, F. A.; Murphy, C.; Eulitz, M.; Wetzel, R.; Solomon, A.

1995-01-01

278

Differential serum protein markers and the clinical severity of asthma  

Directory of Open Access Journals (Sweden)

Full Text Available Norbert Meyer,1,2 Sarah Janine Nuss,1 Thomas Rothe,1 Alexander Siebenhüner,1 Cezmi A Akdis,2 Günter Menz11Hochgebirgsklinik Davos, Davos-Wolfgang, Switzerland; 2Swiss Institute of Allergy and Asthma Research (SIAF, Davos Platz, SwitzerlandBackground: Asthma is a heterogeneous disease characterized by different clinical phenotypes and the involvement of multiple inflammatory pathways. During airway inflammation, many cytokines and chemokines are released and some are detectable in the sera.Objective: Serum chemokines and cytokines, involved in airway inflammation in asthma patients, were investigated.Methods: A total of 191 asthma patients were classified by hierarchical cluster analysis, including the following parameters: forced expiratory volume in 1 second (FEV1, eosinophil cationic protein (ECP serum levels, blood eosinophils, Junipers asthma symptom score, and the change in FEV1, ECP serum levels, and blood eosinophils after 3 weeks of asthma therapy. Serum proteins were measured by multiplex analysis. Receiver operating characteristic (ROC curves were used to evaluate the validity of serum proteins for discriminating between asthma clusters.Results: Classification of asthma patients identified one cluster with high ECP serum levels, increased blood eosinophils, low FEV1 values, and good FEV1 improvement in response to asthma therapy (n=60 and one cluster with low ECP serum levels, low numbers of blood eosinophils, higher FEV1 values, and no FEV1 improvement in response to asthma therapy (n=131. Serum interleukin (IL-8, eotaxin, vascular endothelial growth factor (VEGF, cutaneous T-cell-attracting chemokine (CTACK, growth-related oncogene (GRO-?, and hepatocyte growth factor (HGF were significantly different between the two clusters of asthma patients. ROC analysis for serum proteins calculated a sensitivity of 55.9% and specificity of 75.8% for discriminating between them.Conclusion: Serum cytokine and chemokine levels might be predictors for the severity of asthmatic inflammation, asthma control, and response to therapy, and therefore might be useful for treatment optimization.Keywords: asthma, cluster, phenotype, serum cytokines

Meyer N

2014-04-01

279

Differential Associations of Serum Amyloid A and Pentraxin-3 with Allele-Specific Lipoprotein(a) Levels in African Americans and Caucasians  

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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...

2011-01-01

280

Mitosis-specific phosphorylation of amyloid precursor protein at Threonine 668 leads to its altered processing and association with centrosomes  

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Abstract Background Atypical expression of cell cycle regulatory proteins has been implicated in Alzheimer's disease (AD), but the molecular mechanisms by which they induce neurodegeneration are not well understood. We examined transgenic mice expressing human amyloid precursor protein (APP) and presenilin 1 (PS1) for changes in cell cycle regulatory proteins to determine whether there is a correlation between cell cycle activation and pathology development in AD. Resu...

Judge Monique; Hornbeck Lisa; Potter Huntington; Padmanabhan Jaya

2011-01-01

 
 
 
 
281

Familial Alzheimer's disease mutations alter the stability of the amyloid ?-protein monomer folding nucleus  

Science.gov (United States)

Amyloid ?-protein (A?) oligomers may be the proximate neurotoxins in Alzheimer's disease (AD). Recently, to elucidate the oligomerization pathway, we studied A? monomer folding and identified a decapeptide segment of A?, 21Ala–22Glu–23Asp–24Val–25Gly–26Ser–27Asn–28Lys–29Gly–30Ala, within which turn formation appears to nucleate monomer folding. The turn is stabilized by hydrophobic interactions between Val-24 and Lys-28 and by long-range electrostatic interactions between Lys-28 and either Glu-22 or Asp-23. We hypothesized that turn destabilization might explain the effects of amino acid substitutions at Glu-22 and Asp-23 that cause familial forms of AD and cerebral amyloid angiopathy. To test this hypothesis, limited proteolysis, mass spectrometry, and solution-state NMR spectroscopy were used here to determine and compare the structure and stability of the A?(21–30) turn within wild-type A? and seven clinically relevant homologues. In addition, we determined the relative differences in folding free energies (??Gf) among the mutant peptides. We observed that all of the disease-associated amino acid substitutions at Glu-22 or Asp-23 destabilized the turn and that the magnitude of the destabilization correlated with oligomerization propensity. The Ala21Gly (Flemish) substitution, outside the turn proper (Glu-22–Lys-28), displayed a stability similar to that of the wild-type peptide. The implications of these findings for understanding A? monomer folding and disease causation are discussed.

Grant, Marianne A.; Lazo, Noel D.; Lomakin, Aleksey; Condron, Margaret M.; Arai, Hiromi; Yamin, Ghiam; Rigby, Alan C.; Teplow, David B.

2007-01-01

282

Endogenous C-terminal fragments of beta-amyloid precursor protein from Xenopus laevis skin exudate.  

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Using a monoclonal antibody against the entire C-terminal end of human APP(695) (643-695 sequence) and a monoclonal antibody directed against human beta[1-40] amyloid peptide (betaA), we show the existence of endogenous peptides proteolytically derived from APP in skin exudate of the non transgenic Xenopus laevis frog. The majority of the immunoreactivity is found associated with a 30 kDa molecular species. Biochemical fractionation followed by mass spectrometry identification allowed us to assign this molecular species to C-terminal APP fragments containing all or part of betaA. According to the nature of N- and C-terminal amino acids we identified endogenous beta-, gamma-, epsilon-secretase-like activities, caspase-like activity and numerous endogenous cleavage sites within the beta-amyloid sequence at same sites as those observed in human betaA sequence. All these homologies with human indicate that X. laevis skin exudate is a good natural model to study betaA metabolism. In this way, interestingly, we identified endogenous cleavages at prohormone convertase-like sites not yet described at the same sites in human. Finally, all identified peptide fragments were stably associated with a 20.2 kDa protein. These new observed features suggest new research pathways concerning human betaA metabolism and carriage of hydrophobic peptide fragments issued from APP processing. PMID:17270477

Clamagirand, Christine; El Abida, Boutaïna; Der Garabedian, P Arsene; Hanquez, Chantal; Dubost, Lionel; Marie, Arul; Rholam, Mohamed; Friguet, Bertrand; Cohen, Paul

2007-04-01

283

Age-dependent dysregulation of brain amyloid precursor protein in the Ts65Dn Down syndrome mouse model  

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Individuals with Down syndrome develop ?-amyloid deposition characteristic of early-onset Alzheimer's disease (AD) in mid-life, presumably due to an extra copy of the chromosome 21-located amyloid precursor protein (App) gene. App mRNA and APP metabolite levels were assessed in the brains of Ts65Dn mice, a mouse model of Down syndrome, using qPCR, Western blot analysis, immunoprecipitation, and ELISAs. In spite of the additional App gene copy, App mRNA, APP holoprotein, and all APP metabolit...

Choi, Jennifer H. K.; Berger, Jason D.; Mazzella, Matthew J.; Morales-corraliza, Jose; Cataldo, Anne M.; Nixon, Ralph A.; Ginsberg, Stephen D.; Levy, Efrat; Mathews, Paul M.

2009-01-01

284

Synthetic peptides homologous to prion protein residues 106-147 form amyloid-like fibrils in vitro.  

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Gerstmann-Sträussler-Scheinker disease (GSS) is a prion-related encephalopathy pathologically characterized by massive deposition of prion protein (PrP) amyloid in the central nervous system. The major component of amyloid fibrils isolated from patients of the Indiana kindred of GSS (GSS-Ik) is an 11-kDa fragment of PrP spanning residues 58 to approximately 150. These patients carry a missense mutation of the PRNP gene, causing a Phe-->Ser substitution at codon 198. We investigated fibrillog...

Tagliavini, F.; Prelli, F.; Verga, L.; Giaccone, G.; Sarma, R.; Gorevic, P.; Ghetti, B.; Passerini, F.; Ghibaudi, E.; Forloni, G.

1993-01-01

285

Antibody 9D5 recognizes oligomeric pyroglutamate amyloid-? in a fraction of amyloid-? deposits in Alzheimer's disease without cross-reactivity with other protein aggregates.  

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Recent evidence suggests that soluble oligomeric amyloid-? (A?) assemblies are critically involved in the pathogenesis of Alzheimer's disease (AD). We have generated a conformation-dependent monoclonal antibody (9D5) that selectively recognizes low-molecular weight A?pE3 oligomers, and demonstrated its diagnostic and therapeutic potential. Here, we further characterize the specificity of this antibody by evaluating a spectrum of neurodegeneration-related protein deposits for cross-reactivity, and by comparing the staining pattern of 9D5 with a generic A? antibody that targets a linear epitope (mAb NT244), and with another conformation-dependent A? antibody that selectively labels amyloid fibrils of various molecular weights (pAb OC). The 9D5 antibody does not cross-react with other aggregated protein deposits in brains of progressive supranuclear palsy, corticobasal degeneration, argyrophilic grain disease, Pick's disease, Parkinson's disease, dementia with Lewy bodies, multiple system atrophy, frontotemporal lobar degeneration or amyotrophic lateral sclerosis with TDP-43 inclusions, Creutzfeldt-Jakob disease, and vessel changes in Binswanger encephalopathy, demonstrating the specificity of 9D5 for A? deposits. While NT244 and OC showed a comparable plaque load, 9D5 detected only approximately 15% of the total A? plaque load in the entorhinal cortex, the CA1 region, and the temporal neocortex. Our study further supports a possible therapeutic advantage of 9D5 by the highly specific recognition of an epitope found only in oligomeric assemblies of A?pE3 of AD patients. Moreover, selective binding to only a pathogenetically relevant fraction of A? deposits serves as rationale for passive immunization with 9D5-derivatives by limiting potential side effects of vaccination due to dissolvement of existing amyloid deposits. PMID:22232007

Venkataramani, Vivek; Wirths, Oliver; Budka, Herbert; Härtig, Wolfgang; Kovacs, Gabor G; Bayer, Thomas A

2012-01-01

286

Biochemical indicators of vitamin A deficiency: serum retinol and serum retinol binding protein.  

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Two biochemical indicators are currently recommended for determining whether vitamin A deficiency (VAD) is a public health problem: serum retinol and serum retinol-binding protein (RBP). After consideration of 40 data sets and the original rationale for previously proposed cut-offs, a cut-off for serum retinol concentration was proposed at or =15% of the sampled population. This cut-off should be applied to a representative group of preschool age children (6-71 mo). Because measurement of low serum retinol concentrations requires high precision, analysis should be done by HPLC. For serum RBP, a cut-off cannot be reliably specified, because available data are too few and too variable. However, because serum RBP concentration correlates well with serum retinol concentration, it can be used to determine whether VAD is a public health problem in those populations for which the relationship between serum concentrations of retinol and RBP have been established. More efforts to establish a reliable cut-off for RBP is warranted, because analysis, in particular radial immunodiffusion (RID), is relatively simple and inexpensive. Whereas HPLC and RID analyses must be done in a laboratory, methods are being developed for assessing serum retinol and RBP under more remote conditions. PMID:12221267

de Pee, Saskia; Dary, Omar

2002-09-01

287

A folded and functional protein domain in an amyloid-like fibril.  

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The effect of the polypeptide environment on polyalanine-induced fibril formation was investigated with amyloidogenic fragments from PAPBN1, a nuclear protein controlling polyadenylation. Mutation-caused extensions of the natural 10 alanine sequence up to maximally 17 alanines result in fibril formation of PABPN1 and the development of the disease oculopharyngeal muscular dystrophy (OPMD). We explored the influence of fibril formation on the structure and function of a one-domain protein linked to the fibril-forming part of PABPN1. The well-characterized, stably folded, one-domain protein, cold-shock protein CspB from Bacillus subtilis, was fused either to the C terminus of the entire N-terminal domain of PABPN1 or directly to peptides consisting of 10 or 17 alanine residues. The fusion protein between the N-terminal domain of PABPN1 and CspB formed fibrils in which the structure and activity of CspB were retained. In the fibrils formed by fusions in which the polyalanine sequence was directly linked to CspB, CspB was unfolded. These results indicate that the folded conformation and the function of a protein domain can be maintained in amyloid-like fibrils, and that the distance between this domain and the fibril plays an important role. PMID:18424511

Sackewitz, Mirko; von Einem, Sabrina; Hause, Gerd; Wunderlich, Michael; Schmid, Franz-Xaver; Schwarz, Elisabeth

2008-06-01

288

Prion protein-mediated toxicity of amyloid-? oligomers requires lipid rafts and the transmembrane LRP1.  

Science.gov (United States)

Soluble oligomers of the amyloid-? (A?) peptide cause neurotoxicity, synaptic dysfunction, and memory impairments that underlie Alzheimer disease (AD). The cellular prion protein (PrP(C)) was recently identified as a high affinity neuronal receptor for A? oligomers. We report that fibrillar A? oligomers recognized by the OC antibody, which have been shown to correlate with the onset and severity of AD, bind preferentially to cells and neurons expressing PrP(C). The binding of A? oligomers to cell surface PrP(C), as well as their downstream activation of Fyn kinase, was dependent on the integrity of cholesterol-rich lipid rafts. In SH-SY5Y cells, fluorescence microscopy and co-localization with subcellular markers revealed that the A? oligomers co-internalized with PrP(C), accumulated in endosomes, and subsequently trafficked to lysosomes. The cell surface binding, internalization, and downstream toxicity of A? oligomers was dependent on the transmembrane low density lipoprotein receptor-related protein-1 (LRP1). The binding of A? oligomers to cell surface PrP(C) impaired its ability to inhibit the activity of the ?-secretase BACE1, which cleaves the amyloid precursor protein to produce A?. The green tea polyphenol (-)-epigallocatechin gallate and the red wine extract resveratrol both remodeled the fibrillar conformation of A? oligomers. The resulting nonfibrillar oligomers displayed significantly reduced binding to PrP(C)-expressing cells and were no longer cytotoxic. These data indicate that soluble, fibrillar A? oligomers bind to PrP(C) in a conformation-dependent manner and require the integrity of lipid rafts and the transmembrane LRP1 for their cytotoxicity, thus revealing potential targets to alleviate the neurotoxic properties of A? oligomers in AD. PMID:23386614

Rushworth, Jo V; Griffiths, Heledd H; Watt, Nicole T; Hooper, Nigel M

2013-03-29

289

Differential serum protein markers and the clinical severity of asthma  

Science.gov (United States)

Background Asthma is a heterogeneous disease characterized by different clinical phenotypes and the involvement of multiple inflammatory pathways. During airway inflammation, many cytokines and chemokines are released and some are detectable in the sera. Objective Serum chemokines and cytokines, involved in airway inflammation in asthma patients, were investigated. Methods A total of 191 asthma patients were classified by hierarchical cluster analysis, including the following parameters: forced expiratory volume in 1 second (FEV1), eosinophil cationic protein (ECP) serum levels, blood eosinophils, Junipers asthma symptom score, and the change in FEV1, ECP serum levels, and blood eosinophils after 3 weeks of asthma therapy. Serum proteins were measured by multiplex analysis. Receiver operating characteristic (ROC) curves were used to evaluate the validity of serum proteins for discriminating between asthma clusters. Results Classification of asthma patients identified one cluster with high ECP serum levels, increased blood eosinophils, low FEV1 values, and good FEV1 improvement in response to asthma therapy (n=60) and one cluster with low ECP serum levels, low numbers of blood eosinophils, higher FEV1 values, and no FEV1 improvement in response to asthma therapy (n=131). Serum interleukin (IL)-8, eotaxin, vascular endothelial growth factor (VEGF), cutaneous T-cell-attracting chemokine (CTACK), growth-related oncogene (GRO)-?, and hepatocyte growth factor (HGF) were significantly different between the two clusters of asthma patients. ROC analysis for serum proteins calculated a sensitivity of 55.9% and specificity of 75.8% for discriminating between them. Conclusion Serum cytokine and chemokine levels might be predictors for the severity of asthmatic inflammation, asthma control, and response to therapy, and therefore might be useful for treatment optimization.

Meyer, Norbert; Nuss, Sarah Janine; Rothe, Thomas; Siebenhuner, Alexander; Akdis, Cezmi A; Menz, Gunter

2014-01-01

290

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 "1"2"5I-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 "9"9Tc 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. (author)

1987-01-01

291

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); Neal D. Hammer (Ann Arbor;University of Michigan REV); Matthew R. Chapman (Ann Arbor;University of Michigan REV)

2009-07-21

292

Solvent-Induced Tuning of Internal Structure in a Protein Amyloid Protofibril  

Science.gov (United States)

An important goal in studies of protein aggregation is to obtain an understanding of the structural diversity that is characteristic of amyloid fibril and protofibril structures at the molecular level. In this study, what to our knowledge are novel assays based on time-resolved fluorescence anisotropy decay and dynamic quenching measurements of a fluorophore placed at different specific locations in the primary structure of a small protein, barstar, have been used to determine the extent to which the protein sequence participates in the structural core of protofibrils. The fluorescence measurements reveal the structural basis of how modulating solvent polarity results in the tuning of the protofibril conformation from a pair of parallel ?-sheets in heat-induced protofibrils to a single parallel ?-sheet in trifluorethanol-induced protofibrils. In trifluorethanol-induced protofibrils, the single ?-sheet is shown to be built up from in-register ?-strands formed by nearly the entire protein sequence, while in heat-induced protofibrils, the pair of ?-sheets motif is built up from ?-strands formed by only the last two-third of the protein sequence.

Jha, Anjali; Narayan, Satya; Udgaonkar, Jayant B.; Krishnamoorthy, G.

2012-01-01

293

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; Belfort, Georges

2014-07-01

294

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.

Pflanzner, Thorsten; Petsch, Benjamin; Andre-Dohmen, Bettina; Muller-Schiffmann, Andreas; Tschickardt, Sabrina; Weggen, Sascha; Stitz, Lothar; Korth, Carsten; Pietrzik, Claus U

2012-01-01

295

Oxidative stress induces macroautophagy of amyloid beta-protein and ensuing apoptosis  

DEFF Research Database (Denmark)

There is increasing evidence for the toxicity of intracellular amyloid beta-protein (Abeta) to neurons and the involvement of lysosomes in this process in Alzheimer disease (AD). We have recently shown that oxidative stress, a recognized determinant of AD, enhances macroautophagy and leads to intralysosomal accumulation of Abeta in cultured neuroblastoma cells. We hypothesized that oxidative stress promotes AD by stimulating macroautophagy of Abeta that further may induce cell death by destabilizing lysosomal membranes. To investigate such possibility, we compared the effects of hyperoxia (40% ambient oxygen) in cultured HEK293 cells that were transfected with an empty vector (Vector), wild-type APP (APPwt), or Swedish mutant APP (APPswe). Exposure to hyperoxia for 5 days increased the number of cells with Abeta-containing lysosomes, as well as the number of apoptotic cells, compared to normoxic conditions. The rate of apoptosis in all three cell lines demonstrated dependence on intralysosomal Abeta content (Vector

Zheng, Lin; KÃ¥gedal, Katarina

2009-01-01

296

Phenolic Compounds Prevent Amyloid ?-Protein Oligomerization and Synaptic Dysfunction by Site-specific Binding*  

Science.gov (United States)

Cerebral deposition of amyloid ? protein (A?) is an invariant feature of Alzheimer disease (AD), and epidemiological evidence suggests that moderate consumption of foods enriched with phenolic compounds reduce the incidence of AD. We reported previously that the phenolic compounds myricetin (Myr) and rosmarinic acid (RA) inhibited A? aggregation in vitro and in vivo. To elucidate a mechanistic basis for these results, we analyzed the effects of five phenolic compounds in the A? aggregation process and in oligomer-induced synaptic toxicities. We now report that the phenolic compounds blocked A? oligomerization, and Myr promoted significant NMR chemical shift changes of monomeric A?. Both Myr and RA reduced cellular toxicity and synaptic dysfunction of the A? oligomers. These results suggest that Myr and RA may play key roles in blocking the toxicity and early assembly processes associated with A? through different binding.

Ono, Kenjiro; Li, Lei; Takamura, Yusaku; Yoshiike, Yuji; Zhu, Lijun; Han, Fang; Mao, Xian; Ikeda, Tokuhei; Takasaki, Jun-ichi; Nishijo, Hisao; Takashima, Akihiko; Teplow, David B.; Zagorski, Michael G.; Yamada, Masahito

2012-01-01

297

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  

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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

298

Platelet-derived secreted amyloid-precursor protein-? as a marker for diagnosing Alzheimer's disease.  

Science.gov (United States)

A marker of Alzheimer's disease (AD) with a high sensitivity and specificity would facilitate a diagnosis at early stages. Blood platelets may be of particular interest in search of biomarkers, because they express amyloid-precursor protein (APP), and display a dysfunctional processing in AD. The aim of the present study is to establish and validate an assay for secreted amyloid-precursor protein (sAPP)-? and -? in platelets of AD and mild cognitively impaired (MCI) subjects, compared to healthy young and old controls. Freshly isolated platelet extracts (25 µg) were incubated with or without recombinant BACE1 (beta-site APP-Cleaving Enzyme; ?-secretase, 8U) at 37°C and low pH and the levels of sAPP-? and sAPP-b were measured by specific ELISAs. Our data show that sAPP-? levels were not different between AD, MCI and control subjects. However, sAPP-? levels in MCI and AD were significantly elevated relative to controls. When recombinant BACE1 was added, no changes were seen in sAPP-? levels, but the processed sAPP-? levels were again markedly increased. The sAPP-? processing was specific and selective after 2.5 hours at 37°C, and was possibly mediated by exogenous BACE1, because it was blocked by a BACE1 inhibitor and BACE1 enzyme levels were enhanced in AD patients. Our data reveal that quantitive analysis of platelet sAPP-? assay by ELISA may be a novel diagnostic biomarker for MCI and AD. PMID:23937201

Marksteiner, Josef; Humpel, Christian

2013-11-01

299

From differentiation to proliferation: The secretory amyloid precursor protein as a local mediator of growth in thyroid?epithelial?cells  

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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

300

Erythropoietin binding protein from mammalian serum  

Energy Technology Data Exchange (ETDEWEB)

Purified mammalian erythropoietin binding-protein is disclosed, and its isolation, identification, characterization, purification, and immunoassay are described. The erythropoietin binding protein can be used for regulation of erythropoiesis by regulating levels and half-life of erythropoietin. A diagnostic kit for determination of level of erythropoietin binding protein is also described. 11 figs.

Clemons, G.K.

1997-04-29

 
 
 
 
301

Erythropoietin binding protein from mammalian serum  

Energy Technology Data Exchange (ETDEWEB)

Purified mammalian erythropoietin binding-protein is disclosed, and its isolation, identification, characterization, purification, and immunoassay are described. The erythropoietin binding protein can be used for regulation of erythropoiesis by regulating levels and half-life of erythropoietin. A diagnostic kit for determination of level of erythropoietin binding protein is also described.

Clemons, Gisela K. (Berkeley, CA)

1997-01-01

302

Quantitating metabolites in protein precipitated serum using NMR spectroscopy.  

Science.gov (United States)

Quantitative NMR-based metabolite profiling is challenged by the deleterious effects of abundant proteins in the intact blood plasma/serum, which underscores the need for alternative approaches. Protein removal by ultrafiltration using low molecular weight cutoff filters thus represents an important step. However, protein precipitation, an alternative and simple approach for protein removal, lacks detailed quantitative assessment for use in NMR based metabolomics. In this study, we have comprehensively evaluated the performance of protein precipitation using methanol, acetonitrile, perchloric acid, and trichloroacetic acid and ultrafiltration approaches using 1D and 2D NMR, based on the identification and absolute quantitation of 44 human blood metabolites, including a few identified for the first time in the NMR spectra of human serum. We also investigated the use of a "smart isotope tag," (15)N-cholamine for further resolution enhancement, which resulted in the detection of a number of additional metabolites. (1)H NMR of both protein precipitated and ultrafiltered serum detected all 44 metabolites with comparable reproducibility (average CV, 3.7% for precipitation; 3.6% for filtration). However, nearly half of the quantified metabolites in ultrafiltered serum exhibited 10-74% lower concentrations; specifically, tryptophan, benzoate, and 2-oxoisocaproate showed much lower concentrations compared to protein precipitated serum. These results indicate that protein precipitation using methanol offers a reliable approach for routine NMR-based metabolomics of human blood serum/plasma and should be considered as an alternative to ultrafiltration. Importantly, protein precipitation, which is commonly used by mass spectrometry (MS), promises avenues for direct comparison and correlation of metabolite data obtained from the two analytical platforms to exploit their combined strength in the metabolomics of blood. PMID:24796490

Nagana Gowda, G A; Raftery, Daniel

2014-06-01

303

Genome-Wide Association Study Identifies Two Novel Regions at 11p15.5-p13 and 1p31 with Major Impact on Acute-Phase Serum Amyloid A  

Science.gov (United States)

Elevated levels of acute-phase serum amyloid A (A-SAA) cause amyloidosis and are a risk factor for atherosclerosis and its clinical complications, type 2 diabetes, as well as various malignancies. To investigate the genetic basis of A-SAA levels, we conducted the first genome-wide association study on baseline A-SAA concentrations in three population-based studies (KORA, TwinsUK, Sorbs) and one prospective case cohort study (LURIC), including a total of 4,212 participants of European descent, and identified two novel genetic susceptibility regions at 11p15.5-p13 and 1p31. The region at 11p15.5-p13 (rs4150642; p?=?3.20×10?111) contains serum amyloid A1 (SAA1) and the adjacent general transcription factor 2 H1 (GTF2H1), Hermansky-Pudlak Syndrome 5 (HPS5), lactate dehydrogenase A (LDHA), and lactate dehydrogenase C (LDHC). This region explains 10.84% of the total variation of A-SAA levels in our data, which makes up 18.37% of the total estimated heritability. The second region encloses the leptin receptor (LEPR) gene at 1p31 (rs12753193; p?=?1.22×10?11) and has been found to be associated with CRP and fibrinogen in previous studies. Our findings demonstrate a key role of the 11p15.5-p13 region in the regulation of baseline A-SAA levels and provide confirmative evidence of the importance of the 1p31 region for inflammatory processes and the close interplay between A-SAA, leptin, and other acute-phase proteins.

Hysi, Pirro G.; Lagou, Vasiliki; Waldenberger, Melanie; Tonjes, Anke; Prokopenko, Inga; Heim, Katharina; Blackburn, Hannah; Ried, Janina S.; Kleber, Marcus E.; Mangino, Massimo; Thorand, Barbara; Peters, Annette; Hammond, Christopher J.; Grallert, Harald; Boehm, Bernhard O.; Kovacs, Peter; Geistlinger, Ludwig; Prokisch, Holger; Winkelmann, Bernhard R.; Spector, Tim D.; Wichmann, H.-Erich; Stumvoll, Michael; Soranzo, Nicole; Marz, Winfried; Koenig, Wolfgang; Illig, Thomas; Gieger, Christian

2010-01-01

304

Amyloid fibril formation by native and modified bovine ?-lactoglobulins proceeds through unfolded form of proteins: a comparative study.  

Science.gov (United States)

The misfolding and extracellular amyloid deposition of specific proteins are associated with a large family of human pathologies, often called protein conformational diseases. Despite the many efforts expended to characterize amyloid formation in vitro, there is no deep knowledge about the environment (in which aggregation occurs) as well as mechanism of this type of protein aggregation. Recently, ?-lactoglobulin (?-lg) was driven toward amyloid aggregation under specific extreme conditions. In the present study, citraconylation was employed to neutralize the charges on accessible lysine residues of ?-lg and different approaches such as turbidimetry, thermodynamic analysis, extrinsic fluorimetry and theoretical studies have been successfully used to compare the different behaviors of the native and modified proteins. Kinetic analyses of native ?-lg aggregation showed a gradual development of turbidity, whereas the modified ?-lg displayed an increased propensity toward aggregation. Our results clearly demonstrated that the stability of modified ?-lg is markedly reduced, compared to the native one. Using of TANGO and WALTZ algorithms (as well as modelling softwares) which describe aggregation tendencies of different parts of a protein structure, we suggested critical importance of some of the lysine residues in the aggregation process. The results highlighted the critical role of protein stability and elucidated the underlying role of hydrophobic/electrostatic interactions in lactoglobulin-based experimental system. PMID:21920659

Ghadami, Seyyed Abolghasem; Khodarahmi, Reza; Ghobadi, Sirous; Ghasemi, Moosa; Pirmoradi, Saeed

2011-12-01

305

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

306

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

307

Amyloid Beta Mediates Memory Formation  

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The amyloid precursor protein (APP) undergoes sequential cleavages to generate various polypeptides, including the amyloid [beta] (1-42) peptide (A[beta][1-42]), which is believed to play a major role in amyloid plaque formation in Alzheimer's disease (AD). Here we provide evidence that, in contrast with its pathological role when accumulated,…

Garcia-Osta, Ana; Alberini, Cristina M.

2009-01-01

308

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)

1966-01-01

309

Serum Copper and Plasma Protein Status in Normal Pregnancy  

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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

310

Electrophoretic and immunoelectrophoretic analysis of feline serum proteins.  

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Serum from 28 clinically healthy cats was subjected to agarose gel electrophoresis and the migration distance relative to albumin was determined. The reference values for the relative and absolute concentrations of each protein fraction were determined and compared to previous reports. The immunoelectrophoretic, crossed immunoelectrophoretic and crossed line immunoelectrophoretic pattern, of a pooled sample of serum from clinically normal cats was determined. The cross-reactivity between goat...

Baker, R. J.; Valli, V. E.

1988-01-01

311

Interplay between ?-, ?-, and ?-secretases determines biphasic amyloid-? protein level in the presence of a ?-secretase inhibitor.  

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Amyloid-? (A?) is produced by the consecutive cleavage of amyloid precursor protein (APP) first by ?-secretase, generating C99, and then by ?-secretase. APP is also cleaved by ?-secretase. It is hypothesized that reducing the production of A? in the brain may slow the progression of Alzheimer disease. Therefore, different ?-secretase inhibitors have been developed to reduce A? production. Paradoxically, it has been shown that low to moderate inhibitor concentrations cause a rise in A? production in different cell lines, in different animal models, and also in humans. A mechanistic understanding of the A? rise remains elusive. Here, a minimal mathematical model has been developed that quantitatively describes the A? dynamics in cell lines that exhibit the rise as well as in cell lines that do not. The model includes steps of APP processing through both the so-called amyloidogenic pathway and the so-called non-amyloidogenic pathway. It is shown that the cross-talk between these two pathways accounts for the increase in A? production in response to inhibitor, i.e. an increase in C99 will inhibit the non-amyloidogenic pathway, redirecting APP to be cleaved by ?-secretase, leading to an additional increase in C99 that overcomes the loss in ?-secretase activity. With a minor extension, the model also describes plasma A? profiles observed in humans upon dosing with a ?-secretase inhibitor. In conclusion, this mechanistic model rationalizes a series of experimental results that spans from in vitro to in vivo and to humans. This has important implications for the development of drugs targeting A? production in Alzheimer disease. PMID:23152503

Ortega, Fernando; Stott, Jonathan; Visser, Sandra A G; Bendtsen, Claus

2013-01-11

312

Familial Alzheimer's disease mutations alter the stability of the amyloid beta-protein monomer folding nucleus.  

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Amyloid beta-protein (Abeta) oligomers may be the proximate neurotoxins in Alzheimer's disease (AD). Recently, to elucidate the oligomerization pathway, we studied Abeta monomer folding and identified a decapeptide segment of Abeta, (21)Ala-(22)Glu-(23)Asp-(24)Val-(25)Gly-(26)Ser-(27)Asn-(28)Lys-(29)Gly-(30)Ala, within which turn formation appears to nucleate monomer folding. The turn is stabilized by hydrophobic interactions between Val-24 and Lys-28 and by long-range electrostatic interactions between Lys-28 and either Glu-22 or Asp-23. We hypothesized that turn destabilization might explain the effects of amino acid substitutions at Glu-22 and Asp-23 that cause familial forms of AD and cerebral amyloid angiopathy. To test this hypothesis, limited proteolysis, mass spectrometry, and solution-state NMR spectroscopy were used here to determine and compare the structure and stability of the Abeta(21-30) turn within wild-type Abeta and seven clinically relevant homologues. In addition, we determined the relative differences in folding free energies (DeltaDeltaG(f)) among the mutant peptides. We observed that all of the disease-associated amino acid substitutions at Glu-22 or Asp-23 destabilized the turn and that the magnitude of the destabilization correlated with oligomerization propensity. The Ala21Gly (Flemish) substitution, outside the turn proper (Glu-22-Lys-28), displayed a stability similar to that of the wild-type peptide. The implications of these findings for understanding Abeta monomer folding and disease causation are discussed. PMID:17940047

Grant, Marianne A; Lazo, Noel D; Lomakin, Aleksey; Condron, Margaret M; Arai, Hiromi; Yamin, Ghiam; Rigby, Alan C; Teplow, David B

2007-10-16

313

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

Energy Technology Data Exchange (ETDEWEB)

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 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 {beta}-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.

Patterson, D.; Gardiner, K.; Kao, F.T.; Tanzi, R.; Watkins, P.; Gusella, J.F. (Eleanor Roosevelt Institute for Cancer Research, Denver, CO (USA))

1988-11-01

314

Anti-amyloid Compounds Inhibit ?-Synuclein Aggregation Induced by Protein Misfolding Cyclic Amplification (PMCA)*  

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Filaments made of ?-synuclein form the characteristic Lewy pathology in Parkinson and other diseases. The formation of ?-synuclein filaments can be reproduced in vitro by incubation of recombinant protein, but the filament growth is very slow and highly variable and so unsuitable for fast high throughput anti-aggregation drug screening. To overcome this obstacle we have investigated whether the protein misfolding cyclic amplification (PMCA) technique, used for fast amplification of prion protein aggregates, could be adapted for growing ?-synuclein aggregates and thus suitable for screening of drugs to affect ?-synuclein aggregation for the treatment of the yet incurable ?-synucleinopathies. Circular dichroism, electron microscopy, and native and SDS-polyacrylamide gels were used to demonstrate ?-synuclein aggregate formation by PMCA, and the strain imprint of the ?-synuclein fibrils was studied by proteinase K digestion. We also demonstrated that ?-synuclein fibrils are able to seed new ?-synuclein PMCA reactions and to enter and aggregate in cells in culture. In particular, we have generated a line of “chronically infected” cells, which transmit ?-synuclein aggregates even after multiple passages. To evaluate the sensitivity of the PMCA system as an ?-synuclein anti-aggregating drug screening assay a panel of 10 drugs was tested. Anti-amyloid compounds proved efficient in inhibiting ?-synuclein fibril formation induced by PMCA. Our results show that ?-synuclein PMCA is a fast and reproducible system that could be used as a high throughput screening method for finding new ?-synuclein anti-aggregating compounds.

Herva, Maria Eugenia; Zibaee, Shahin; Fraser, Graham; Barker, Roger A.; Goedert, Michel; Spillantini, Maria Grazia

2014-01-01

315

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

316

Effects of the English (H6R) and Tottori (D7N) Familial Alzheimer Disease Mutations on Amyloid ?-Protein Assembly and Toxicity*  

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Mutations in the amyloid ?-protein (A?) precursor gene cause autosomal dominant Alzheimer disease in a number of kindreds. In two such kindreds, the English and the Tottori, the mutations produce amyloid ?-proteins containing amino acid substitutions, H6R and D7N, respectively, at the peptide N terminus. To elucidate the structural and biological effects of the mutations, we began by examining monomer conformational dynamics and oligomerization. Relative to their wild type homologues, and ...

Ono, Kenjiro; Condron, Margaret M.; Teplow, David B.

2010-01-01

317

TUDCA, a bile acid, attenuates amyloid precursor protein processing and amyloid-? deposition in APP/PS1 mice.  

Science.gov (United States)

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by accumulation of amyloid-? (A?) peptide in the hippocampus and frontal cortex of the brain, leading to progressive cognitive decline. The endogenous bile acid tauroursodeoxycholic acid (TUDCA) is a strong neuroprotective agent in several experimental models of disease, including neuronal exposure to A?. Nevertheless, the therapeutic role of TUDCA in AD pathology has not yet been ascertained. Here we report that feeding APP/PS1 double-transgenic mice with diet containing 0.4 % TUDCA for 6 months reduced accumulation of A? deposits in the brain, markedly ameliorating memory deficits. This was accompanied by reduced glial activation and neuronal integrity loss in TUDCA-fed APP/PS1 mice compared to untreated APP/PS1 mice. Furthermore, TUDCA regulated lipid-metabolism mediators involved in A? production and accumulation in the brains of transgenic mice. Overall amyloidogenic APP processing was reduced with TUDCA treatment, in association with, but not limited to, modulation of ?-secretase activity. Consequently, a significant decrease in A?(1-40) and A?(1-42) levels was observed in both hippocampus and frontal cortex of TUDCA-treated APP/PS1 mice, suggesting that chronic feeding of TUDCA interferes with A? production, possibly through the regulation of lipid-metabolism mediators associated with APP processing. These results highlight TUDCA as a potential therapeutic strategy for the prevention and treatment of AD. PMID:22438081

Nunes, Ana F; Amaral, Joana D; Lo, Adrian C; Fonseca, Maria B; Viana, Ricardo J S; Callaerts-Vegh, Zsuzsanna; D'Hooge, Rudi; Rodrigues, Cecília M P

2012-06-01

318

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

319

Chemical labelling of active serum thioester proteins for quantification  

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The complement serum proteins C3 and C4 and the protease inhibitor ?-2 macroglobulin are all members of the C3/?-2M thioester protein family, an evolutionarily ancient and conserved family that contains an intrachain thioester bond. The chemistry of the thioester bond is a key to the function of the thioester proteins. All these proteins function by covalently linking to their target by acyl transfer of the protein via the thioester moiety. We show that the signature thioester bond can be t...

Holm, Lotta; Ackland, Gareth L.; Edwards, Mark R.; Breckenridge, Ross A.; Sim, Robert B.; Offer, John

2012-01-01

320

Soluble amyloid-? precursor protein binds its cell surface receptor in a cooperative fashion with glypican and syndecan proteoglycans.  

Science.gov (United States)

Proteolytic processing of amyloid-? precursor protein (APP) generates the amyloid-? peptide, which plays a central role in Alzheimer disease. The physiological function of APP and its proteolytic fragments, however, remains barely understood. Here we show that, on the basis of its binding characteristics, the secreted ectodomain of APP (sAPP) is a new member of the heparin-binding growth factor superfamily. Like other of its members, sAPP binds in a bivalent manner to the plasma membrane with two different subdomains. The N-terminal growth-factor-like domain (GFLD) is necessary and sufficient for protein-receptor binding, whereas the E2-domain mediates interaction with membrane-anchored heparan sulfate proteoglycans (HSPGs). The membrane-anchored HSPGs function as low-affinity co-receptors for sAPP and enhance the affinity to the sAPP receptor. Our findings provide a solid basis for the further identification of this receptor. PMID:23986479

Reinhard, Constanze; Borgers, Marianne; David, Guido; De Strooper, Bart

2013-11-01

 
 
 
 
321

The Functions of the Amyloid Precursor Protein Gene and Its Derivative Peptides: II Experimental Evidence and Clinical Studies  

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Full Text Available In vitro studies suggest Amyloid Precursor Protein Gene (APP is involved in interaction with the extracellular matrix, neurite growth, adhesion, development, synaptic function, platelet function, and interaction with GTP binding proteins. In vivo experiments show a role in embryonic development, response to cerebral excitotoxicity and gliosis, response to brain injury including ischaemia, hypothalamic function, locomotor function, learning and memory. In vitro observations indicate A? has a role in amyloid formation, excitotoxic neuronal injury, tachykinin interaction, endothelial vasoconstrictor response, calcium and oxidative stress, free radical interaction, cell membrane fluidity, apoptosis, astrocyte stimulation, and microglial interaction. Other studies suggest important roles for A? oligomers in synaptic function and as an antimicrobial peptide. In vivo investigations show involvement in memory function, the blood brain barrier, and tachykinin response to cerebral injury.

Peter K. Panegyres

2011-09-01

322

Serum acute phase protein concentrations in dogs with spirocercosis and their association with esophageal neoplasia - A prospective cohort study.  

Science.gov (United States)

Spirocerca lupi, the dog esophageal worm, typically induces formation of esophageal nodules, which may transform to sarcoma. Ante mortem discrimination between benign and malignant esophageal masses is challenging. Serum acute phase proteins (APPs) are utilized in diagnosis and prognosis of various canine diseases as markers of inflammation. This study characterized serum APPs concentrations in dogs with benign and malignant esophageal spirocercosis and evaluated their accuracy in differentiating benign from malignant lesions. Seventy-eight client-owned dogs with esophageal spirocercosis were included. Serum C-reactive protein (CRP), haptoglobin, serum-amyloid A (SAA) and albumin concentrations were measured upon diagnosis and follow-up visits, and compared with healthy dogs, and between malignant and benign cases. Haptoglobin, CRP and SAA concentrations were higher, and albumin concentration was lower (Pspirocercosis is characterized by an acute phase reaction, both at presentation and during treatment. When concentrations of all four APPs are within reference range, esophageal malignancy is highly unlikely. Although concentrations of all positive APPs were significantly higher in suspected neoplastic cases compared to benign ones, moderate discriminatory power limits their clinical use. Neither APP was useful to monitor response to treatment. PMID:24656552

Nivy, Ran; Caldin, Marco; Lavy, Eran; Shaabon, Keren; Segev, Gilad; Aroch, Itamar

2014-06-16

323

Distribution of Serum Total Protein in Elderly Chinese  

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The serum total protein levels of the elderly possibly decrease gradually with aging. However, serum total protein levels are not suitable as a uniform reference standard for the elderly at different ages and genders. Thus, we investigated the total serum protein distribution in different gender and age groups of 11,453 elderly individuals aged ?60 years and without liver or renal disease from Lianyungang, Jiangsu, China. The total protein levels (TPL) of these individuals exhibited normal distribution (Z?=?1.206, P?=?0.109), whereas the reference range (95% CI) was 54.1 g/L to 82.3 g/L. TPL was higher in females than in males for those aged between 60 and 75 years, whereas no significant difference was observed for those aged between 80 and 95 years. TPL was negatively correlated with age in males (r?=??0.1342, P<0.05), females (r?=??0.304, P<0.05), and the total group (r?=??0.2136, P<0.05). TPL also decreased with aging and showed a faster rate in women than in men. These results indicated that an appropriate range of serum total protein based on age and gender differences should be used for clinical applications.

Tian, Chang-Rong; Qian, Li; Shen, Xiao-Zhu; Li, Jia-Jing; Wen, Jiang-Tao

2014-01-01

324

Dosage of amyloid precursor protein affects axonal contact guidance in Down syndrome.  

Science.gov (United States)

Amyloid precursor protein (APP), encoded on Hsa21, functions as a cell adhesion molecule (CAM) in axonal growth cones (GCs) of the developing brain. We show here that axonal GCs of human fetal Down syndrome (DS) neurons (and of a DS mouse model) overexpress APP protein relative to euploid controls. We investigated whether DS neurons generate an abnormal, APP-dependent GC phenotype in vitro. On laminin, which binds APP and ?1 integrins (Itgb1), DS neurons formed enlarged and faster-advancing GCs compared to controls. On peptide matrices that bind APP only, but not on those binding exclusively Itgb1 or L1CAM, DS GCs were significantly enlarged (2.0-fold), formed increased close adhesions (1.8-fold), and advanced faster (1.4-fold). In assays involving alternating stripes of monospecific matrices, human control GCs exhibited no preference for any of the substrates, whereas DS GCs preferred the APP-binding matrix (cross-over decreased significantly from 48.2 to 27.2%). Reducing APP expression in DS GCs with siRNA normalized most measures of the phenotype, including substrate choice. These experiments show that human DS neurons exhibit an APP-dependent, abnormal GC phenotype characterized by increased adhesion and altered contact guidance. The results suggest that APP overexpression may perturb axonal pathfinding and circuit formation in developing DS brain. PMID:24036883

Sosa, Lucas J; Postma, Nienke L; Estrada-Bernal, Adriana; Hanna, M; Guo, R; Busciglio, Jorge; Pfenninger, Karl H

2014-01-01

325

Metalloprotease Meprin ? Generates Nontoxic N-terminal Amyloid Precursor Protein Fragments in Vivo*  

Science.gov (United States)

Identification of physiologically relevant substrates is still the most challenging part in protease research for understanding the biological activity of these enzymes. The zinc-dependent metalloprotease meprin ? is known to be expressed in many tissues with functions in health and disease. Here, we demonstrate unique interactions between meprin ? and the amyloid precursor protein (APP). Although APP is intensively studied as a ubiquitously expressed cell surface protein, which is involved in Alzheimer disease, its precise physiological role and relevance remain elusive. Based on a novel proteomics technique termed terminal amine isotopic labeling of substrates (TAILS), APP was identified as a substrate for meprin ?. Processing of APP by meprin ? was subsequently validated using in vitro and in vivo approaches. N-terminal APP fragments of about 11 and 20 kDa were found in human and mouse brain lysates but not in meprin ??/? mouse brain lysates. Although these APP fragments were in the range of those responsible for caspase-induced neurodegeneration, we did not detect cytotoxicity to primary neurons treated by these fragments. Our data demonstrate that meprin ? is a physiologically relevant enzyme in APP processing.

Jefferson, Tamara; Causevic, Mirsada; auf dem Keller, Ulrich; Schilling, Oliver; Isbert, Simone; Geyer, Rebecca; Maier, Wladislaw; Tschickardt, Sabrina; Jumpertz, Thorsten; Weggen, Sascha; Bond, Judith S.; Overall, Christopher M.; Pietrzik, Claus U.; Becker-Pauly, Christoph

2011-01-01

326

Mechanisms regulating the dimerization of the Amyloid Precursor Protein and their role in its trafficking and processing  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Alzheimer’s disease is the most common neurodegenerative disorder. One of the major neuropathological lesions characterizing AD is the senile plaque. The senile plaques are found in brains of AD patients and are built-up by accumulation of A? peptide. A? derives from the large amyloid precursor protein (APP) by the sequential cleavage by the ?- and ?-secretases. Ten APP isoforms, produced by pre-mRNA alternative splicing have been identified. The two major isoforms of human APP, APP695 ...

Ben Khalifa, Naouel

2011-01-01

327

Quantitation of amyloid beta-protein (A beta) in the cortex during aging and in Alzheimer's disease.  

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In this study we sought to learn about when and how amyloid beta-protein (A beta) accumulates in the cortex of normal individuals and about the difference in the A beta accumulation between normal aged and Alzheimer's disease (AD) brains. From consecutive autopsy cases and AD cases, hippocampus CA1 and occipitotemporal cortex T4 were sampled for A beta quantitation by the well characterized two-site enzyme immunoassays (EIAs). There was a strong tendency toward A beta 42 accumulation between ...

Funato, H.; Yoshimura, M.; Kusui, K.; Tamaoka, A.; Ishikawa, K.; Ohkoshi, N.; Namekata, K.; Okeda, R.; Ihara, Y.

1998-01-01

328

Induction of methionine-sulfoxide reductases protects neurons from amyloid ?-protein insults in vitro and in vivo  

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Amyloid ?-protein (A?) self-assembly into toxic oligomers and fibrillar polymers is believed to cause Alzheimer’s disease (AD). In the AD brain, a high percentage of A? contains Met-sulfoxide at position 35, though the role this modification plays in AD is not clear. Oxidation of Met35 to sulfoxide has been reported to decrease A? assembly and neurotoxicity, whereas surprisingly, Met35 oxidation to sulfone yields similar toxicity to unoxidized A?. We hypothesized that the lower toxicit...

Moskovitz, Jackob; Maiti, Panchanan; Lopes, Dahabada H. J.; Oien, Derek B.; Attar, Aida; Liu, Tingyu; Mittal, Shivina; Hayes, Jane; Bitan, Gal

2011-01-01

329

Structural Basis for Matrix Metalloproteinase-2 (MMP-2)-selective Inhibitory Action of ?-Amyloid Precursor Protein-derived Inhibitor*  

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Unlike other synthetic or physiological inhibitors for matrix metalloproteinases (MMPs), the ?-amyloid precursor protein-derived inhibitory peptide (APP-IP) having an ISYGNDALMP sequence has a high selectivity toward MMP-2. Our previous study identified amino acid residues of MMP-2 essential for its selective inhibition by APP-IP and demonstrated that the N to C direction of the decapeptide inhibitor relative to the substrate-binding cleft of MMP-2 is opposite that of substrate. However, det...

2011-01-01

330

Amyloid fibril in hereditary cerebral hemorrhage with amyloidosis (HCHWA) is related to the gastroentero-pancreatic neuroendocrine protein, gamma trace  

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Amyloid fibrils were isolated from the leptomeningeal blood vessels obtained at autopsy from three Icelandic patients dying of Hereditary Cerebral Hemorrhage with Amyloidosis (HCHWA) and verified by Congo red staining and electron microscopy. Gel filtration on Sephadex and Ultrogel columns yielded predominantly one component (molecular weight 11,500 daltons) and also another minor component (molecular weight 15,800 daltons). Automated amino terminal sequencing showed these proteins to be simi...

1983-01-01

331

LOVASTATIN INHIBITS AMYLOID PRECURSOR PROTEIN (APP) ?-CLEAVAGE THROUGH REDUCTION OF APP DISTRIBUTION IN LUBROL WX EXTRACTABLE LOW DENSITY LIPID RAFTS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Previous studies have described that statins (inhibitors of cholesterol and isoprenoid biosynthesis) inhibit the output of amyloid-? (A?) in the animal model and thus decrease risk of Alzheimer's disease. However, their action mechanism(s) in APP processing and A? generation is not fully understood. Here we report that lovastatin treatment reduced A? output in cultured hippocampal neurons as a result of reduced A? precursor protein (APP) levels and ?-secretase activities in low density ...

Won, Je-seong; Im, Yeong-bin; Khan, Mushfiquddin; Contreras, Miguel; Singh, Avtar K.; Singh, Inderjit

2008-01-01

332

Co-localization of the amyloid precursor protein and the Notch intracellular domains in nuclear transcription factories  

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The ?-amyloid precursor protein (APP) plays a major role in Alzheimer’s disease. The APP intracellular domain (AICD), together with Fe65 and Tip60, localizes to spherical nuclear AFT complexes that might represent sites of transcription. We now show that endogenous AICD is targeted to similar nuclear spots. AFT complexes were closely associated with Cajal and PML bodies but did not localize to nucleoli or splicing speckles. Live imaging revealed that AFT complexes were highly mobile within...

Konietzko, Uwe; Goodger, Zoe? V.; Meyer, Michelle; Kohli, Bernhard M.; Bosset, Je?ro?me; Lahiri, Debomoy K.; Nitsch, Roger M.

2010-01-01

333

Amyloid ?-Protein Is Degraded by Cellular Angiotensin-converting Enzyme (ACE) and Elevated by an ACE Inhibitor*  

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Human genetic data have associated angiotensin-converting enzyme (ACE) with Alzheimer disease (AD), and purified ACE has been reported to cleave synthetic amyloid ?-protein (A?) in vitro. Whether deficiency in ACE activity, arising from genetic alteration or pharmacological inhibition, can decrease A? degradation and allow A? accumulation in intact cells is unknown. We cloned ACE from human neuroblastoma cells and showed that it had posttranslational processing and enzymatic activity typi...

Hemming, Matthew L.; Selkoe, Dennis J.

2005-01-01

334

Histone Deacetylase Inhibitor Valproic Acid Inhibits Cancer Cell Proliferation via Down-regulation of the Alzheimer Amyloid Precursor Protein*  

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The ?-amyloid precursor protein (APP) represents a type I transmembrane glycoprotein that is ubiquitously expressed. In the brain, it is a key player in the molecular pathogenesis of Alzheimer disease. Its physiological function is however less well understood. Previous studies showed that APP is up-regulated in prostate, colon, pancreatic tumor, and oral squamous cell carcinoma. In this study, we show that APP has an essential role in growth control of pancreatic and colon cancer. Abundant ...

2010-01-01

335

Valsartan lowers brain ?-amyloid protein levels and improves spatial learning in a mouse model of Alzheimer disease  

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Recent epidemiological evidence suggests that some antihypertensive medications may reduce the risk for Alzheimer disease (AD). We screened 55 clinically prescribed antihypertensive medications for AD-modifying activity using primary cortico-hippocampal neuron cultures generated from the Tg2576 AD mouse model. These agents represent all drug classes used for hypertension pharmacotherapy. We identified 7 candidate antihypertensive agents that significantly reduced AD-type ?-amyloid protein (A...

Wang, Jun; Ho, Lap; Chen, Linghong; Zhao, Zhong; Zhao, Wei; Qian, Xianjuan; Humala, Nelson; Seror, Ilana; Bartholomew, Sadie; Rosendorff, Clive; Pasinetti, Giulio Maria

2007-01-01

336

ADAM9 inhibition increases membrane activity of ADAM10 and controls ?-secretase processing of amyloid precursor protein.  

Science.gov (United States)

Prodomains of A disintegrin and metalloproteinase (ADAM) metallopeptidases can act as highly specific intra- and intermolecular inhibitors of ADAM catalytic activity. The mouse ADAM9 prodomain (proA9; amino acids 24-204), expressed and characterized from Escherichia coli, is a competitive inhibitor of human ADAM9 catalytic/disintegrin domain with an overall inhibition constant of 280 ± 34 nM and high specificity toward ADAM9. In SY5Y neuroblastoma cells overexpressing amyloid precursor protein, proA9 treatment reduces the amount of endogenous ADAM10 enzyme in the medium while increasing membrane-bound ADAM10, as shown both by Western and activity assays with selective fluorescent peptide substrates using proteolytic activity matrix analysis. An increase in membrane-bound ADAM10 generates higher levels of soluble amyloid precursor protein ? in the medium, whereas soluble amyloid precursor protein ? levels are decreased, demonstrating that inhibition of ADAM9 increases ?-secretase activity on the cell membrane. Quantification of physiological ADAM10 substrates by a proteomic approach revealed that substrates, such as epidermal growth factor (EGF), HER2, osteoactivin, and CD40-ligand, are increased in the medium of BT474 breast tumor cells that were incubated with proA9, demonstrating that the regulation of ADAM10 by ADAM9 applies for many ADAM10 substrates. Taken together, our results demonstrate that ADAM10 activity is regulated by inhibition of ADAM9, and this regulation may be used to control shedding of amyloid precursor protein by enhancing ?-secretase activity, a key regulatory step in the etiology of Alzheimer disease. PMID:21956108

Moss, Marcia L; Powell, Gary; Miller, Miles A; Edwards, Lori; Qi, Bin; Sang, Qing-Xiang Amy; De Strooper, Bart; Tesseur, Ina; Lichtenthaler, Stefan F; Taverna, Mara; Zhong, Julia Li; Dingwall, Colin; Ferdous, Taheera; Schlomann, Uwe; Zhou, Pei; Griffith, Linda G; Lauffenburger, Douglas A; Petrovich, Robert; Bartsch, Jörg W

2011-11-25

337

ADAM9 Inhibition Increases Membrane Activity of ADAM10 and Controls ?-Secretase Processing of Amyloid Precursor Protein*  

Science.gov (United States)

Prodomains of A disintegrin and metalloproteinase (ADAM) metallopeptidases can act as highly specific intra- and intermolecular inhibitors of ADAM catalytic activity. The mouse ADAM9 prodomain (proA9; amino acids 24–204), expressed and characterized from Escherichia coli, is a competitive inhibitor of human ADAM9 catalytic/disintegrin domain with an overall inhibition constant of 280 ± 34 nm and high specificity toward ADAM9. In SY5Y neuroblastoma cells overexpressing amyloid precursor protein, proA9 treatment reduces the amount of endogenous ADAM10 enzyme in the medium while increasing membrane-bound ADAM10, as shown both by Western and activity assays with selective fluorescent peptide substrates using proteolytic activity matrix analysis. An increase in membrane-bound ADAM10 generates higher levels of soluble amyloid precursor protein ? in the medium, whereas soluble amyloid precursor protein ? levels are decreased, demonstrating that inhibition of ADAM9 increases ?-secretase activity on the cell membrane. Quantification of physiological ADAM10 substrates by a proteomic approach revealed that substrates, such as epidermal growth factor (EGF), HER2, osteoactivin, and CD40-ligand, are increased in the medium of BT474 breast tumor cells that were incubated with proA9, demonstrating that the regulation of ADAM10 by ADAM9 applies for many ADAM10 substrates. Taken together, our results demonstrate that ADAM10 activity is regulated by inhibition of ADAM9, and this regulation may be used to control shedding of amyloid precursor protein by enhancing ?-secretase activity, a key regulatory step in the etiology of Alzheimer disease.

Moss, Marcia L.; Powell, Gary; Miller, Miles A.; Edwards, Lori; Qi, Bin; Sang, Qing-Xiang Amy; De Strooper, Bart; Tesseur, Ina; Lichtenthaler, Stefan F.; Taverna, Mara; Zhong, Julia Li; Dingwall, Colin; Ferdous, Taheera; Schlomann, Uwe; Zhou, Pei; Griffith, Linda G.; Lauffenburger, Douglas A.; Petrovich, Robert; Bartsch, Jorg W.

2011-01-01

338

Serum Protein Signatures Differentiating Autoimmune Pancreatitis versus Pancreatic Cancer  

Science.gov (United States)

Autoimmune pancreatitis (AIP) is defined by characteristic lymphoplasmacytic infiltrate, ductal strictures and a pancreatic enlargement or mass that can mimic pancreatic cancer (PaCa). The distinction between this benign disease and pancreatic cancer can be challenging. However, an accurate diagnosis may pre-empt the misdiagnosis of cancer, allowing the appropriate medical treatment of AIP and, consequently, decreasing the number of unnecessary pancreatic resections. Mass spectrometry (MS) and two-dimensional differential gel electrophoresis (2D-DIGE) have been applied to analyse serum protein alterations associated with AIP and PaCa, and to identify protein signatures indicative of the diseases. Patients' sera were immunodepleted from the 20 most prominent serum proteins prior to further 2D-DIGE and image analysis. The identity of the most-discriminatory proteins detected, was performed by MS and ELISAs were applied to confirm their expression. Serum profiling data analysis with 2D-DIGE revealed 39 protein peaks able to discriminate between AIP and PaCa. Proteins were purified and further analysed by MALDI-TOF-MS. Peptide mass fingerprinting led to identification of eleven proteins. Among them apolipoprotein A-I, apolipoprotein A-II, transthyretin, and tetranectin were identified and found as 3.0-, 3.5-, 2-, and 1.6-fold decreased in PaCa sera, respectively, whereas haptoglobin and apolipoprotein E were found to be 3.8- and 1.6-fold elevated in PaCa sera. With the exception of haptoglobin the ELISA results of the identified proteins confirmed the 2D-DIGE image analysis characteristics. Integration of the identified serum proteins as AIP markers may have considerable potential to provide additional information for the diagnosis of AIP to choose the appropriate treatment.

Fritz, Stefan; Hinz, Ulf; Schnolzer, Martina; Kempf, Tore; Warnken, Uwe; Michel, Angelika; Pawlita, Michael; Werner, Jens

2013-01-01

339

Serum protein signatures differentiating autoimmune pancreatitis versus pancreatic cancer.  

Science.gov (United States)

Autoimmune pancreatitis (AIP) is defined by characteristic lymphoplasmacytic infiltrate, ductal strictures and a pancreatic enlargement or mass that can mimic pancreatic cancer (PaCa). The distinction between this benign disease and pancreatic cancer can be challenging. However, an accurate diagnosis may pre-empt the misdiagnosis of cancer, allowing the appropriate medical treatment of AIP and, consequently, decreasing the number of unnecessary pancreatic resections. Mass spectrometry (MS) and two-dimensional differential gel electrophoresis (2D-DIGE) have been applied to analyse serum protein alterations associated with AIP and PaCa, and to identify protein signatures indicative of the diseases. Patients' sera were immunodepleted from the 20 most prominent serum proteins prior to further 2D-DIGE and image analysis. The identity of the most-discriminatory proteins detected, was performed by MS and ELISAs were applied to confirm their expression. Serum profiling data analysis with 2D-DIGE revealed 39 protein peaks able to discriminate between AIP and PaCa. Proteins were purified and further analysed by MALDI-TOF-MS. Peptide mass fingerprinting led to identification of eleven proteins. Among them apolipoprotein A-I, apolipoprotein A-II, transthyretin, and tetranectin were identified and found as 3.0-, 3.5-, 2-, and 1.6-fold decreased in PaCa sera, respectively, whereas haptoglobin and apolipoprotein E were found to be 3.8- and 1.6-fold elevated in PaCa sera. With the exception of haptoglobin the ELISA results of the identified proteins confirmed the 2D-DIGE image analysis characteristics. Integration of the identified serum proteins as AIP markers may have considerable potential to provide additional information for the diagnosis of AIP to choose the appropriate treatment. PMID:24349355

Felix, Klaus; Hauck, Oliver; Fritz, Stefan; Hinz, Ulf; Schnölzer, Martina; Kempf, Tore; Warnken, Uwe; Michel, Angelika; Pawlita, Michael; Werner, Jens

2013-01-01

340

Serum C reactive protein in infective endocarditis.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

C reactive protein (CRP) was measured serially in 29 patients with infective endocarditis. Twenty one patients were initially treated with antimicrobial drugs. In 13, serial measurement of CRP concentrations showed a progressive return to normal (less than 10 mg/l), which correlated with a satisfactory recovery. Of the remainder (eight patients), five had persistently high concentrations of CRP, indicating a failure to respond to antimicrobial treatment alone. Two of these five patients died ...

1988-01-01

 
 
 
 
341

Blood serum components and serum protein test of Hybro-PG broilers of different ages  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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-t [...] ransferase (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; OC, Freitas Neto; AC, Laurentiz; OM, Junqueira; JJ, Fagliari.

342

Charged gold nanoparticles with essentially zero serum protein adsorption in undiluted fetal bovine serum.  

Science.gov (United States)

The adsorption of even a single serum protein molecule on a gold nanosphere used in biomedical imaging may increase the size too much for renal clearance. In this work, we designed charged ~5 nm Au nanospheres coated with binary mixed-charge ligand monolayers that do not change in size upon incubation in pure fetal bovine serum (FBS). This lack of protein adsorption was unexpected in view of the fact that the Au surface was moderately charged. The mixed-charge monolayers were composed of anionic citrate ligands modified by place exchange with naturally occurring amino acids: either cationic lysine or zwitterionic cysteine ligands. The zwitterionic tips of either the lysine or cysteine ligands interact weakly with the proteins and furthermore increase the distance between the "buried" charges closer to the Au surface and the interacting sites on the protein surface. The ~5 nm nanospheres were assembled into ~20 nm diameter nanoclusters with strong near-IR absorbance (of interest in biomedical imaging and therapy) with a biodegradable polymer, PLA(1k)-b-PEG(10k)-b-PLA(1k). Upon biodegradation of the polymer in acidic solution, the nanoclusters dissociated into primary ~5 nm Au nanospheres, which also did not adsorb any detectable serum protein in undiluted FBS. PMID:23565806

Murthy, Avinash K; Stover, Robert J; Hardin, William G; Schramm, Robert; Nie, Golay D; Gourisankar, Sai; Truskett, Thomas M; Sokolov, Konstantin V; Johnston, Keith P

2013-05-29

343

[Physiocochemical properties of blood serum proteins of coal miners].  

Science.gov (United States)

Using disk electrophoresis in the polyacrylamide gel, blood serum proteins were studied in miners working under conditions of the combine (the control group) and drilling-and-blasting (the contact with carbon oxide, nitrogen oxides) driving technique under normal temperature conditions. 26--27 protein fractions characterized by mobility, thermolability under definite conditions of the experiment and the contitative content were obtained. It is shown that the contact with carbon oxide and nitrogen oxides causes changes in the rpoperties of certain proteins (II3, globulins--2 alpha 1, 3 alpha 1, 2 beta, 2 alpha 2, 5 alpha 2, 6 alpha 2, 7 alpha 2) of miners blood serum. Some of these proteins are supposed to participate in the adaptation reactions of the organism. PMID:473394

Nandakova, V N; Zemliakova, L F; Sukhanov, V V; Min'ko, L A

1979-01-01

344

Rapid determination of thyroxine binding proteins of human serum  

Directory of Open Access Journals (Sweden)

Full Text Available A simple method is described for determing thyroxine binding proteins in human serum by electrophoresis at pH 8.6, using cellulose acetate membrane as the supporting medium. The procedure had high reliability in sera of normal subjects, pregnant women and patients with decreased thyroxine binding capacity of thyroxine binding globulin.

Arima,Terukatsu

1976-02-01

345

Degradation of amyloid beta-protein by a metalloprotease secreted by microglia and other neural and non-neural cells.  

Science.gov (United States)

Amyloid beta-protein (Abeta) is the major component of neuritic (amyloid) plaques in Alzheimer's disease, and its deposition is an early and constant event in the complex pathogenetic cascade of the disease. Although many studies have focused on the biosynthetic processing of the beta-amyloid precursor protein and on the production and polymerization of Abeta, understanding the degradation and clearance of Abeta has received very little attention. By incubating the conditioned medium of metabolically labeled Abeta-secreting cells with media of various cultured cell lines, we observed a time-dependent decrease in the amount of Abeta in the mixed media. The factor principally responsible for this decrease was a secreted metalloprotease released by both neural and non-neural cells. Among the cells examined, the microglial cell line, BV-2, produced the most Abeta-degrading activity. The protease was completely blocked by the metalloprotease inhibitor, 1,10-phenanthroline, and partially inhibited by EDTA, whereas inhibitors of other protease classes produced little or no inhibition. Substrate analysis suggests that the enzyme was a non-matrix metalloprotease. The protease cleaved both Abeta1-40 and Abeta1-42 peptides secreted by beta-amyloid precursor protein-transfected cells but failed to degrade low molecular weight oligomers of Abeta that form in the culture medium. Lipopolysaccharide, a stimulator of macrophages/microglia, activated BV-2 cells to increase their Abeta-degrading metalloprotease activity. We conclude that secreted Abeta1-40 and Abeta1-42 peptides are constitutively degraded by a metalloprotease released by microglia and other neural cells, providing a potential mechanism for the clearance of Abeta in brain tissue. PMID:9045694

Qiu, W Q; Ye, Z; Kholodenko, D; Seubert, P; Selkoe, D J

1997-03-01

346

Duplication of amyloid precursor protein (APP), but not prion protein (PRNP) gene is a significant cause of early onset dementia in a large UK series  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Amyloid precursor protein gene (APP) duplications have been identified in screens of selected probands with early onset familial Alzheimer's disease (FAD). A causal role for copy number variation (CNV) in the prion protein gene (PRNP) in prion dementias is not known. We aimed to determine the prevalence of copy number variation in APP and PRNP in a large referral series, test a screening method for detection of the same, and expand knowledge of clinical phenotype. We used a 3-tiered screening...

Mcnaughton, Daniel; Knight, William; Guerreiro, Rita; Ryan, Natalie; Lowe, Jessica; Poulter, Mark; Nicholl, David J.; Hardy, John; Revesz, Tamas; Lowe, James; Rossor, Martin; Collinge, John; Mead, Simon

2012-01-01

347

Duplication of amyloid precursor protein (APP), but not prion protein (PRNP) gene is a significant cause of early onset dementia in a large UK series.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Amyloid precursor protein gene (APP) duplications have been identified in screens of selected probands with early onset familial Alzheimer's disease (FAD). A causal role for copy number variation (CNV) in the prion protein gene (PRNP) in prion dementias is not known. We aimed to determine the prevalence of copy number variation in APP and PRNP in a large referral series, test a screening method for detection of the same, and expand knowledge of clinical phenotype. We used a 3-tiered screening...

Mcnaughton, D.; Knight, W.; Guerreiro, R.; Ryan, N.; Poulter, M.; Nicholl, D. J.; Hardy, J.; Revesz, T.; Lowe, J.; Rossor, M.; Collinge, J.; Mead, S.

2012-01-01

348

THE INSECT HOMOLOGUE OF THE AMYLOID PRECURSOR PROTEIN INTERACTS WITH THE HETEROTRIMERIC G PROTEIN Go? IN AN IDENTIFIED POPULATION OF MIGRATORY NEURONS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The amyloid precursor protein (APP) is the source of A? fragments implicated in the formation of senile plaques in Alzheimer’s Disease (AD). APP-related proteins are also expressed at high levels in the embryonic nervous system and may serve a variety of developmental functions, including the regulation of neuronal migration. To investigate this issue, we have cloned an orthologue of APP (msAPPL) from the moth, Manduca sexta, a preparation that permits in vivo manipulations of an identifie...

2005-01-01

349

Alzheimer amyloid-? oligomer bound to postsynaptic prion protein activates Fyn to impair neurons.  

Science.gov (United States)

Amyloid-beta (A?) oligomers are thought to trigger Alzheimer's disease pathophysiology. Cellular prion protein (PrP(C)) selectively binds oligomeric A? and can mediate Alzheimer's disease-related phenotypes. We examined the specificity, distribution and signaling of A?-PrP(C) complexes, seeking to understand how they might alter the function of NMDA receptors (NMDARs) in neurons. PrP(C) is enriched in postsynaptic densities, and A?-PrP(C) interaction leads to Fyn kinase activation. Soluble A? assemblies derived from the brains of individuals with Alzheimer's disease interacted with PrP(C) to activate Fyn. A? engagement of PrP(C)-Fyn signaling yielded phosphorylation of the NR2B subunit of NMDARs, which was coupled to an initial increase and then a loss of surface NMDARs. A?-induced dendritic spine loss and lactate dehydrogenase release required both PrP(C) and Fyn, and human familial Alzheimer's disease transgene-induced convulsive seizures did not occur in mice lacking PrP(C). These results delineate an A? oligomer signal transduction pathway that requires PrP(C) and Fyn to alter synaptic function, with deleterious consequences in Alzheimer's disease. PMID:22820466

Um, Ji Won; Nygaard, Haakon B; Heiss, Jacqueline K; Kostylev, Mikhail A; Stagi, Massimiliano; Vortmeyer, Alexander; Wisniewski, Thomas; Gunther, Erik C; Strittmatter, Stephen M

2012-09-01

350

Solid-state NMR analysis of the ?-strand orientation of the protofibrils of amyloid ?-protein  

International Nuclear Information System (INIS)

Highlights: ? The supramolecular structure of A?42 protofibrils was analyzed by solid-state NMR. ? The Ala-21 residue in the A?42 protofibrils is included in a slightly disordered ?-strand. ? The A?42 protofibrils do not form intermolecular in-register parallel ?-sheets. -- Abstract: Alzheimer’s disease (AD) is caused by abnormal deposition (fibrillation) of a 42-residue amyloid ?-protein (A?42) in the brain. During the process of fibrillation, the A?42 takes the form of protofibrils with strong neurotoxicity, and is thus believed to play a crucial role in the pathogenesis of AD. To elucidate the supramolecular structure of the A?42 protofibrils, the intermolecular proximity of the Ala-21 residues in the A?42 protofibrils was analyzed by 13C–13C rotational resonance experiments in the solid state. Unlike the A?42 fibrils, an intermolecular 13C–13C correlation was not found in the A?42 protofibrils. This result suggests that the ?-strands of the A?42 protofibrils are not in an in-register parallel orientation. A?42 monomers would assemble to form protofibrils with the ?-strand conformation, then transform into fibrils by forming intermolecular parallel ?-sheets.

2012-11-30

351

Amyloid beta-protein: experiment and theory on the 21-30 fragment.  

Science.gov (United States)

The structure of the 21-30 fragment of the amyloid beta-protein (Abeta) was investigated by ion mobility mass spectrometry and replica exchange dynamics simulations. Mutations associated with familial Alzheimer's disease (E22G, E22Q, E22K, and D23N) of Abeta(21-30) were also studied, in order to understand any structural changes that might occur with these substitutions. The structure of the WT peptide shows a bend and a perpendicular turn in the backbone which is maintained by a network of D23 hydrogen bonding. Results for the mutants show that substitutions at E22 do little to alter the overall structure of the fragment. A substitution at D23 resulted in a change of structure for Abeta(21-30). A comparison of these gas-phase studies to previous solution-phase studies reveals that the peptide can fold in the absence of solvent to a structure also seen in solution, highlighting the important role of the D23 hydrogen bonding network in stabilizing the fragment's folded structure. PMID:19341254

Murray, Megan M; Krone, Mary Griffin; Bernstein, Summer L; Baumketner, Andrij; Condron, Margaret M; Lazo, Noel D; Teplow, David B; Wyttenbach, Thomas; Shea, Joan-Emma; Bowers, Michael T

2009-04-30

352

Synthesis and Purification of Highly Hydrophobic Peptides Derived from the C-Terminus of Amyloid ?-Protein.  

Science.gov (United States)

Some biotechnological inventions involve expensive, sophisticated machines. Others are relatively simple innovations that nevertheless address, and solve difficult problems. Synthesis and purification of highly hydrophobic peptides can be a difficult and challenging task, particularly when these peptides have low solubility in both aqueous and organic solvents. Here we describe the synthesis and purification of a series of peptides derived from the hydrophobic C-terminus of the 42-residue form of amyloid ?-protein (A?42), a peptide believed to be the primary cause for Alzheimer's disease (AD). The series of C-terminal fragments (CTFs) had the general formula A?(x-42), x=28-39, which potentially can be used as inhibitors of A?42 assembly and neurotoxicity. Synthesis and purification of peptides containing 8-residues or less were straightforward. However, HPLC purification of longer peptides was problematic and provided <1% yield in particularly difficult cases due to very poor solubility in the solvent systems used both in reverse- and in normal phase chromatography. Modification of the purification protocol using water precipitation followed by removal of scavengers by washing with diethyl ether circumvented the need for HPLC purification and provided these peptides with purity as high as HPLC-purified peptides and substantially increased yield. PMID:19898686

Condron, M M; Monien, B H; Bitan, G

2008-01-01

353

Synthesis and Purification of Highly Hydrophobic Peptides Derived from the C-Terminus of Amyloid ?-Protein  

Science.gov (United States)

Some biotechnological inventions involve expensive, sophisticated machines. Others are relatively simple innovations that nevertheless address, and solve difficult problems. Synthesis and purification of highly hydrophobic peptides can be a difficult and challenging task, particularly when these peptides have low solubility in both aqueous and organic solvents. Here we describe the synthesis and purification of a series of peptides derived from the hydrophobic C-terminus of the 42-residue form of amyloid ?-protein (A?42), a peptide believed to be the primary cause for Alzheimer’s disease (AD). The series of C-terminal fragments (CTFs) had the general formula A?(x-42), x=28–39, which potentially can be used as inhibitors of A?42 assembly and neurotoxicity. Synthesis and purification of peptides containing 8-residues or less were straightforward. However, HPLC purification of longer peptides was problematic and provided <1% yield in particularly difficult cases due to very poor solubility in the solvent systems used both in reverse- and in normal phase chromatography. Modification of the purification protocol using water precipitation followed by removal of scavengers by washing with diethyl ether circumvented the need for HPLC purification and provided these peptides with purity as high as HPLC-purified peptides and substantially increased yield.

Condron, M.M.; Monien, B.H.; Bitan, G.

2009-01-01

354

The Amyloid ?-Protein: Experiment and Theory on the 21-30 Fragment  

Science.gov (United States)

The structure of the 21-30 fragment of the amyloid ?-protein (A?) was investigated by ion-mobility mass spectrometry and replica exchange dynamics simulations. Mutations associated with familial Alzheimer’s disease (E22G, E22Q, E22K, and D23N) of A?(21-30) were also studied, in order to understand any structural changes that might occur with these substitutions. The structure of the WT peptide shows a bend and a perpendicular turn in the backbone which is maintained by a network of D23 hydrogen bonding. Results for the mutants show that substitutions at E22 do little to alter the overall structure of the fragment. A substitution at D23 resulted in a change of structure for A?(21-30). A comparison of these gas-phase studies to previous solution-phase studies reveals that the peptide can fold in the absence of solvent to a structure also seen in solution, highlighting the important role of the D23 hydrogen bonding network in stabilizing the fragment’s folded structure.

Murray, Megan M; Krone, Mary Griffin; Bernstein, Summer L.; Baumketner, Andrij; Condron, Margaret M.; Lazo, Noel D.; Teplow, David B.; Wyttenbach, Thomas; Shea, Joan-Emma; Bowers, Michael T.

2009-01-01

355

Synthetic amyloid-beta oligomers impair long-term memory independently of cellular prion protein.  

Science.gov (United States)

Inability to form new memories is an early clinical sign of Alzheimer's disease (AD). There is ample evidence that the amyloid-beta (Abeta) peptide plays a key role in the pathogenesis of this disorder. Soluble, bio-derived oligomers of Abeta are proposed as the key mediators of synaptic and cognitive dysfunction, but more tractable models of Abeta-mediated cognitive impairment are needed. Here we report that, in mice, acute intracerebroventricular injections of synthetic Abeta(1-42) oligomers impaired consolidation of the long-term recognition memory, whereas mature Abeta(1-42) fibrils and freshly dissolved peptide did not. The deficit induced by oligomers was reversible and was prevented by an anti-Abeta antibody. It has been suggested that the cellular prion protein (PrP(C)) mediates the impairment of synaptic plasticity induced by Abeta. We confirmed that Abeta(1-42) oligomers interact with PrP(C), with nanomolar affinity. However, PrP-expressing and PrP knock-out mice were equally susceptible to this impairment. These data suggest that Abeta(1-42) oligomers are responsible for cognitive impairment in AD and that PrP(C) is not required. PMID:20133875

Balducci, Claudia; Beeg, Marten; Stravalaci, Matteo; Bastone, Antonio; Sclip, Alessandra; Biasini, Emiliano; Tapella, Laura; Colombo, Laura; Manzoni, Claudia; Borsello, Tiziana; Chiesa, Roberto; Gobbi, Marco; Salmona, Mario; Forloni, Gianluigi

2010-02-01

356

Synthetic amyloid-? oligomers impair long-term memory independently of cellular prion protein  

Science.gov (United States)

Inability to form new memories is an early clinical sign of Alzheimer’s disease (AD). There is ample evidence that the amyloid-? (A?) peptide plays a key role in the pathogenesis of this disorder. Soluble, bio-derived oligomers of A? are proposed as the key mediators of synaptic and cognitive dysfunction, but more tractable models of A??mediated cognitive impairment are needed. Here we report that, in mice, acute intracerebroventricular injections of synthetic A?1–42 oligomers impaired consolidation of the long-term recognition memory, whereas mature A?1–42 fibrils and freshly dissolved peptide did not. The deficit induced by oligomers was reversible and was prevented by an anti-A? antibody. It has been suggested that the cellular prion protein (PrPC) mediates the impairment of synaptic plasticity induced by A?. We confirmed that A?1–42 oligomers interact with PrPC, with nanomolar affinity. However, PrP-expressing and PrP knock-out mice were equally susceptible to this impairment. These data suggest that A?1–42 oligomers are responsible for cognitive impairment in AD and that PrPC is not required.

Balducci, Claudia; Beeg, Marten; Stravalaci, Matteo; Bastone, Antonio; Sclip, Alessandra; Biasini, Emiliano; Tapella, Laura; Colombo, Laura; Manzoni, Claudia; Borsello, Tiziana; Chiesa, Roberto; Gobbi, Marco; Salmona, Mario; Forloni, Gianluigi

2010-01-01

357

Early stages of probable Alzheimer disease are associated with changes in platelet amyloid precursor protein forms.  

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Previous findings demonstrated an altered pattern of amyloid precursor protein (APP) forms in platelets of Alzheimer disease (AD) patients, compared both with healthy control subjects or patients with non-Alzheimer-type dementia. The present study aims to evaluate whether platelet APP form ratio (APPr) is altered in patients with early stage AD. We selected 40 patients with early stage AD and 40 age-matched healthy controls. Compared with controls (mean+/-SD=0.91+/-0.3), mean APPr was decreased in AD (mean+/-SD=0.46+/-0.26, p<0.0001). Sixteen very mild AD patients (clinical dementia rating=0.5), identified among the AD group, showed a significant decrease of APPr values (mean+/-SD=0.50+/-0.3, p<0.0001). These findings indicate that alteration of APP processing in platelets is an early event and suggest that this assay might be of diagnostic value in differentiating mild AD from normal ageing. PMID:12522675

Borroni, B; Colciaghi, F; Corsini, P; Akkawi, N; Rozzini, L; Del Zotto, E; Talarico, G; Cattabeni, F; Lenzi, G L; Di Luca, M; Padovani, A

2002-12-01

358

Differential processing of amyloid precursor protein in brain and in peripheral blood leukocytes.  

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Because amyloid precursor protein (APP) fragments exist in many tissues throughout the body, including the fluid compartments of blood, they have been the focus of numerous investigations into their potential as a biomarker of Alzheimer's disease. Using immunohistochemistry, immunoelectron microscopy, Western blot, and quantitative real-time-polymerase chain reaction (qRT-PCR) analysis we examined whether APP processing in leukocytes is analogous to APP processing in the brain. We show APP immunoreactivity at light and electron microscopic levels in the cytoplasm and nucleus of peripheral blood leukocytes (PBL) yet our Western blot analysis data demonstrated that brain and PBL contain different APP fragments and differentially expressed APP processing enzymes. A Disintegrin and Metalloproteinase domain 10 (ADAM10), nicastrin, and beta-secretase 2 (BACE2) were present in brain but were undetected in PBL. Presenilin 1 and beta-secretase 1 (BACE1) were detected in both tissues but showed different patterns in Western blots. Quantitative PCR results identified Neprilysin as the only processing enzyme we interrogated in which Western and quantitative PCR data coincided. Although our data on differential processing of APP in brain and PBL point to exercising caution when generalizing between blood and brain with regard to mechanisms, they have no implications regarding utility as biomarkers. PMID:23298733

Delvaux, Elaine; Bentley, Karen; Stubbs, Victoria; Sabbagh, Marwan; Coleman, Paul D

2013-06-01

359

Overexpression of amyloid precursor protein in acute myeloid leukemia enhances extramedullary infiltration by MMP-2.  

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It is known that leukemia patients with extramedullary infiltration (EMI) have a worse prognosis than patients without it. Recent data indicate that the amyloid precursor protein (APP) is involved in cell adhesion, motility, and proliferation. The expression of APP and its prognostic significance in acute myeloid leukemia (AML) have not been studied. Our study shows that AML/ETO(+) leukemia patients that overexpress APP easily get EMI and that their long-term survival rate is lower than patients without overexpression of APP. In an in vitro study, we knocked down APP in Kasumi-1 cells using small interfering RNA (siRNA). Transwell data show that siRNA/APP substantially impairs cell migration, but it does not inhibit cell proliferation. Furthermore, by quantitative real-time polymerase chain reaction and Western blot, we found that siRNA/APP decreases MMP-2 expression in vitro. Our study provides a novel clue that APP is involved in the extramedullary infiltration of leukemia by MMP-2. PMID:23179400

Jiang, Ling; Yu, Guopan; Meng, Wei; Wang, Zhixiang; Meng, Fanyi; Ma, Wenli

2013-04-01

360

3,3',4',5'-tetrahydroxyflavone induces formation of large aggregates of amyloid ? protein.  

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Amyloid ? protein (A?) self-assembles into insoluble fibrils, and forms the senile plaques associated with Alzheimer's disease. 3,3',4',5'-Tetrahydroxyflavone, a synthetic analogue of the natural flavonoid fisetin, has been found to potently inhibit A? fibril formation. In the present study, we investigated how inhibition of A? fibril formation by this flavonoid affects A? conformation and neurotoxicity. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of A?1-42 (20?µM) incubated with or without 3,3',4',5'-tetrahydroxyflavone demonstrated that 3,3',4',5'-tetrahydroxyflavone (100?µM) rapidly caused formation of atypical A? conformers, which appeared as a very broad, smear-like band in the high molecular weight region and were distinguishable from soluble A? oligomers or mature A? fibrils. Transmission electron microscopy (TEM) revealed that large spherical A? aggregates were preferentially formed in the presence of 3,3',4',5'-tetrahydroxyflavone. The SDS-resistant, smear-like band on SDS-PAGE and the large spherical aggregates in TEM both disappeared after heat treatment (100°C, 10?min). Furthermore, a neurotoxicity assay with cultured rat hippocampal neurons demonstrated that A? incubated with 3,3',4',5'-tetrahydroxyflavone was significantly less toxic than A? incubated without the flavonoid. These results suggest that the newly synthesized fisetin analogue 3,3',4',5'-tetrahydroxyflavone directly produces atypical, large A? aggregates and reduces A? toxicity. PMID:24789998

Ushikubo, Hiroko; Tanimoto, Yui; Abe, Kazuho; Asakawa, Tomohiro; Kan, Toshiyuki; Akaishi, Tatsuhiro

2014-01-01

 
 
 
 
361

E22? Mutation in Amyloid ?-Protein Promotes ?-Sheet Transformation, Radical Production, and Synaptotoxicity, But Not Neurotoxicity  

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Oligomers of 40- or 42-mer amyloid ?-protein (A?40, A?42) cause cognitive decline and synaptic dysfunction in Alzheimer's disease. We proposed the importance of a turn at Glu22 and Asp23 of A?42 to induce its neurotoxicity through the formation of radicals. Recently, a novel deletion mutant at Glu22 (E22?) of A?42 was reported to accelerate oligomerization and synaptotoxicity. To investigate this mechanism, the effects of the E22? mutation in A?42 and A?40 on the transformation of ?-sheets, radical production, and neurotoxicity were examined. Both mutants promoted ?-sheet transformation and the formation of radicals, while their neurotoxicity was negative. In contrast, E22P-A?42 with a turn at Glu22 and Asp23 exhibited potent neurotoxicity along with the ability to form radicals and potent synaptotoxicity. These data suggest that conformational change in E22?-A? is similar to that in E22P-A?42 but not the same, since E22?-A?42 exhibited no cytotoxicity, unlike E22P-A?42 and wild-type A?42.

Suzuki, Takayuki; Murakami, Kazuma; Izuo, Naotaka; Kume, Toshiaki; Akaike, Akinori; Nagata, Tetsu; Nishizaki, Tomoyuki; Tomiyama, Takami; Takuma, Hiroshi; Mori, Hiroshi; Irie, Kazuhiro

2011-01-01

362

Effects of cerebrovascular disease on amyloid precursor protein metabolites in cerebrospinal fluid  

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Full Text Available Abstract Background Alzheimer's disease (AD and cerebrovascular disease (CVD including chronic small vessel disease of the brain (SVD are the most frequent causes of dementia. AD is associated with metabolism of amyloid precursor protein (APP and low levels of amyloid-? peptide (A? X-42 in the cerebrospinal fluid (CSF. CVD and SVD are established risk factors for AD, brain white matter lesions (WML are established surrogate markers for SVD and are also associated with reduced CSF A?X-42. A cohort survey was performed to examine whether SVD or acute CVD affects APP metabolism and to explore a potential association between WML and APP metabolism in two groups; cognitively impaired patients, subjective and mild (SCI and MCI and stroke patients. Through measurements of CSF APP metabolite levels in patients with a wide range of WML volumes, this study aimed to determine how SVD influences APP metabolism. Methods Sixty-three patients were included: 37 with subjective cognitive impairment (SCI or mild cognitive impairment (MCI without stroke, and 26 after acute stroke. Chronic and acute WML volume and infarct volume were determined by magnetic resonance imaging (MRI post-scan processing, and CSF levels of ?- and ?-cleaved soluble APP (sAPP-? and sAPP-?, A?X-38, A?X-40 and A?X-42 were determined. The Mann-Whitney test was used to compare the patient groups. Chronic and acute WML volumes, infarct volume, age, and sex were used as predictors for CSF biomarker levels in linear regression analysis. Results CSF levels of sAPP-? and sAPP-? were strongly correlated (r = 0.95, p p p p ? 0.005; p ? 0.01; p ? 0.01; p ? 0.05; p ? 0.05 respectively, but not with acute WML or infarct volumes. Conclusions Lower CSF levels of sAPP-? and sAPP-? in the stroke group than in the SCI/MCI group and an inverse correlation with chronic WML indicate that ischemia lowers the levels of CSF sAPP metabolites and suggests that APP axonal transport or metabolism may be affected in SVD of the brain.

Rosengren Lars

2010-07-01

363

Modeling sporadic alzheimer's disease: the insulin resistant brain state generates multiple long-term morphobiological abnormalities inclusive hyperphosphorylated tau protein and amyloid-beta. A Synthesis  

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Nosologically, Alzheimer's disease (AD) is not a single disorder. Missense gene mutations involved in increased formation of the amyloid-beta protein precursor derivatives amyloid-beta (Abeta)_{1-40} and Abeta_{1-42/43} lead to autosomal dominant familial AD, found in the minority of AD cases. However, millions of subjects suffer from sporadic AD (sAD) of late onset, for which no convincing evidence suggests Abeta as the primary disease-generating compoun...

Salkovic-petrisic, M.; Osmanovic, J.; Gru?nblatt, E.; Riederer, P.; Hoyer, S.

2009-01-01

364

?-Amyloid precursor protein transgenic mice that harbor diffuse A? deposits but do not form plaques show increased ischemic vulnerability: Role of inflammation  

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?-amyloid (A?), derived form the ?-amyloid precursor protein (APP), is important for the pathogenesis of Alzheimer's disease (AD), which is characterized by progressive decline of cognitive functions, formation of A? plaques and neurofibrillary tangles, and loss of neurons. However, introducing a human wild-type or mutant APP gene to rodent models of AD does not result in clear neurodegeneration, suggesting that contributory factors lowering the threshold of neuronal death may be present ...

Koistinaho, Milla; Kettunen, Mikko I.; Goldsteins, Gundars; Keina?nen, Riitta; Salminen, Antero; Ort, Michael; Bures, Jan; Liu, David; Kauppinen, Risto A.; Higgins, Linda S.; Koistinaho, Jari

2002-01-01

365

Interactions of lecithinized superoxide dismutase with serum proteins and cells.  

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Superoxide dismutase covalently bound to four lecithin molecules (PC-SOD) is known to be retained in circulating blood for a prolonged period and has a high affinity for cells, resulting in beneficial therapeutic effects in animal disease models. In this study, we evaluated the interaction of PC-SOD with biological components, such as serum proteins and cells, to clarify the mechanism underlying the improved pharmacokinetics of SOD induced by lecithin chemical modification (lecithinization). PC-SOD was distributed in the plasma but not in blood cells after being added to the blood. PC-SOD formed a complex with serum protein(s) such as albumin, whereas unmodified SOD did not. The cellular content of PC-SOD was markedly higher than that of unmodified SOD, and was distributed in lysosomes. The pathway associated with the cellular uptake was found to involve clathrin-/caveolae-independent and cholesterol-sensitive endocytosis. Overall, our data indicated that the increased hydrophobicity of lecithinized SOD enhanced its association to both serum protein(s) and plasma membrane microdomains. The former inhibited SOD excretion and promoted long-term retention in circulating blood, whereas the latter enhanced internalization into cells via endocytosis. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:1987-1994, 2014. PMID:24867597

Ishihara, Tsutomu; Nara, Shunsuke; Mizushima, Tohru

2014-07-01

366

Inhibition of amyloid fibril growth and dissolution of amyloid fibrils by curcumin-gold nanoparticles.  

Science.gov (United States)

Inhibition of amyloid fibrillation and clearance of amyloid fibrils/plaques are essential for the prevention and treatment of various neurodegenerative disorders involving protein aggregation. Herein, we report curcumin-functionalized gold nanoparticles (Au-curcumin) of hydrodynamic diameter 10-25?nm, which serve to inhibit amyloid fibrillation and disintegrate/dissolve amyloid fibrils. In nanoparticle form, curcumin is water-soluble and can efficiently interact with amyloid protein/peptide, offering enhanced performance in inhibiting amyloid fibrillation and dissolving amyloid fibrils. Our results imply that nanoparticle-based artificial molecular chaperones may offer a promising therapeutic approach to combat neurodegenerative disease. PMID:24691975

Palmal, Sharbari; Maity, Amit Ranjan; Singh, Brijesh Kumar; Basu, Sreetama; Jana, Nihar R; Jana, Nikhil R

2014-05-12

367

Identification of serum proteins bound to industrial nanomaterials.  

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Nanoparticles (NPs) are decorated with proteins and other biomolecules when they get into contact with biological systems. The presence of proteins in cell culture medium can therefore have effects on the biological outcome in cell-based tests. In this study, the manufactured nanomaterials silicon dioxide (SiO(2)), titanium dioxide (TiO(2)), iron-III-oxide (Fe(2)O(3)), and carbon black (CB) were used to study their interaction with single proteins from bovine and human plasma (albumin, fibrinogen and IgG) as well as with complete human serum. The protein binding capacity of the material was investigated and 1D gel electrophoresis was used to separate the bound proteins and to identify the bands by matrix-assisted laser desorption/ionisation-time-of-flight (MALDI-TOF) mass spectrometry. We found that the NP surface chemistry had a great impact on the amount of bound protein with distinct ligands for each of the tested particles. The hydrophobic CB NPs bound much more protein than the hydrophilic metal oxide NPs. Among the single proteins investigated, fibrinogen showed the strongest affinity for SiO(2), TiO(2) and CB NPs. The identified proteins from human serum adsorbed to these NPs were very different. Only apolipoprotein A1 was found to be adsorbed to all NPs. These studies will help to explain the different degree of biological responses observed after in vitro exposure of cells in the absence or presence of serum and might also support the interpretation of in vivo experiments were NPs come directly into contact with blood plasma. PMID:22001751

Ruh, Hermelindis; Kühl, Boris; Brenner-Weiss, Gerald; Hopf, Carsten; Diabaté, Silvia; Weiss, Carsten

2012-01-01

368

Highly increased CSF tau protein and decreased ?-amyloid (1-42) in sporadic CJD: a discrimination from Alzheimer's disease?  

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The aim was to quantify tau protein and ?-amyloid (A?42) in the CSF of patients with sporadic Creutzfeldt-Jakob disease (CJD), Alzheimer's disease (AD), and controls. Double sandwich enzyme linked immunosorbent assays (ELISAs) were used for measurments. Tau was increased 58-fold in CJD and 3.5-fold in AD compared with controls, whereas A?42 was decreased 0.5-fold in both CJD and AD. A cut off level for tau protein at 2131 pg/ml successfully discriminated CJD from AD (100%...

Kapaki, E.; Kilidireas, K.; Paraskevas, G.; Michalopoulou, M.; Patsouris, E.

2001-01-01

369

Reduced amyloidogenic processing of the amyloid ?-protein precursor by the small-molecule Differentiation Inducing Factor-1  

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The detection of cell cycle proteins in Alzheimer’s disease (AD) brains may represent an early event leading to neurodegeneration. To identify cell cycle modifiers with anti-A? properties, we assessed the effect of Differentiation-Inducing Factor-1 (DIF-1), a unique, small-molecule from Dictyostelium discoideum, on the proteolysis of the amyloid ?-protein precursor (APP) in a variety of different cell types. We show that DIF-1 slows cell cycle progression through G0/G1 that correlates wit...

2009-01-01

370

Cerebrospinal fluid amyloid beta and tau protein: Biomarkers for Alzheimer's disease  

Directory of Open Access Journals (Sweden)

Full Text Available Background/Aim. Introduction of acetylcholine esterase inhibitors as a symptomatic treatment of Alzheimer's disease (AD has additionally highlighted the importance of diagnostic markers in cerebrospinal fluid (CSF for early AD diagnosis: low level of 42 amino acid form of amyloid-? peptide (A?42, and levels of tau protein (T-tau and phosphorylated tau protein (P-tau. The aim of this study was to diagnostic potential of CSF biomarkers T-tau, P-tau and A?42 as biochemical markers for AD. Methods. Lumbar puncture was performed in 63 patients with AD and 26 control subjects who passed orthopedic surgery. The Innotest, ELISA sandwich test (Innogenetics - Belgium was used for measuring the levels of T-tau, P-tau and A?42. Results. The patients and the control group did not differ in age, education and sex. Mean levels of CSF T-tau and P-tau were significantly higher in the patients with AD (p < 0.001 compared to the control group, in contrast to significantely lower CSF A?42 in AD group (p < 0.001. A significant progressive decrease of A?42, as well as significant progressive increase of T-tau and P-tau was found among AD subgroups (according to MMSE staging and controls. Conclusion. The obtained results suggest that these biomarkers may be supportive in the diagnosis of AD, especially in the early course of the disease and could be used in the routine clinical practice considering the approaching target therapeutics.

Mandi? Gorana

2008-01-01

371

Amino acid position-specific contributions to amyloid beta-protein oligomerization.  

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Understanding the structural and assembly dynamics of the amyloid beta-protein (Abeta) 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 Abeta 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, or 40 (for Abeta40) or 42 (for Abeta42). The effects of these substitutions were probed using circular dichroism spectroscopy, thioflavin T binding, electron microscopy, PICUP, and mass spectrometry. All peptides displayed a random coil --> alpha/beta --> beta transition, but substitution-dependent alterations in assembly kinetics and conformer complexity were observed. Tyr(1)-substituted homologues of Abeta40 and Abeta42 assembled the slowest and yielded unusual patterns of oligomer bands in gel electrophoresis experiments, suggesting oligomer compaction had occurred. Consistent with this suggestion was the observation of relatively narrow [Tyr(1)]Abeta40 fibrils. Substitution of Abeta40 at the C terminus decreased the population conformational complexity and substantially extended the highest order of oligomers observed. This latter effect was observed in both Abeta40 and Abeta42 as the Tyr substitution position number increased. The ability of a single substitution (Tyr(1)) to alter Abeta assembly kinetics and the oligomer frequency distribution suggests that the N terminus is not a benign peptide segment, but rather that Abeta conformational dynamics and assembly are affected significantly by the competition between the N and C termini to form a stable complex with the central hydrophobic cluster. PMID:19567875

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

2009-08-28

372

Etude Systematique des Proteines Plasmatiques et Seriques du Porc (Systematic Study of Plasma and Serum Proteins in the Pig).  

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The serum and plasma proteins of a normal pig were studied 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...

F. Daburon C. Hatchikan J. P. Schmidt P. Nizza

1966-01-01

373

GxxxG motifs within the amyloid precursor protein transmembrane sequence are critical for the etiology of A?42  

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Processing of the amyloid precursor protein (APP) by ?- and ?-secretases leads to the generation of amyloid-? (A?) peptides with varying lengths. Particularly A?42 contributes to cytotoxicity and amyloid accumulation in Alzheimer's disease (AD). However, the precise molecular mechanism of A?42 generation has remained unclear. Here, we show that an amino-acid motif GxxxG within the APP transmembrane sequence (TMS) has regulatory impact on the A? species produced. In a neuronal cell system, mutations of glycine residues G29 and G33 of the GxxxG motif gradually attenuate the TMS dimerization strength, specifically reduce the formation of A?42, leave the level of A?40 unaffected, but increase A?38 and shorter A? species. We show that glycine residues G29 and G33 are part of a dimerization site within the TMS, but do not impair oligomerization of the APP ectodomain. We conclude that ?-secretase cleavages of APP are intimately linked to the dimerization strength of the substrate TMS. The results demonstrate that dimerization of APP TMS is a risk factor for AD due to facilitating A?42 production.

Munter, Lisa-Marie; Voigt, Philipp; Harmeier, Anja; Kaden, Daniela; Gottschalk, Kay E; Weise, Christoph; Pipkorn, Rudiger; Schaefer, Michael; Langosch, Dieter; Multhaup, Gerd

2007-01-01

374

Serum protein concentrations in calves with experimentally induced pneumonic pasteurellosis  

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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 deter...

2003-01-01

375

Identification of Immunogenic and Serum Binding Proteins of Staphylococcus epidermidis  

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Staphylococcus epidermidis is a commensal of human skin and a leading cause of nosocomial bloodstream infections. Limited information is available about S. epidermidis proteins that are expressed upon transition to the bloodstream or those involved in host-pathogen interactions. A cell surface fraction from S. epidermidis 0-47 grown in rabbit serum to mimic environmental signals encountered during a bloodstream infection was separated by two-dimensional (2D) gel electrophoresis. Following 2D ...

Sellman, Bret R.; Howell, Alan P.; Kelly-boyd, Cari; Baker, Steve M.

2005-01-01

376

Development of transgenic rats producing human ?-amyloid precursor protein as a model for Alzheimer's disease: Transgene and endogenous APP genes are regulated tissue-specifically  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Alzheimer's disease (AD is a devastating neurodegenerative disorder that affects a large and growing number of elderly individuals. In addition to idiopathic disease, AD is also associated with autosomal dominant inheritance, which causes a familial form of AD (FAD. Some instances of FAD have been linked to mutations in the ?-amyloid protein precursor (APP. Although there are numerous mouse AD models available, few rat AD models, which have several advantages over mice, have been generated. Results Fischer 344 rats expressing human APP driven by the ubiquitin-C promoter were generated via lentiviral vector infection of Fischer 344 zygotes. We generated two separate APP-transgenic rat lines, APP21 and APP31. Serum levels of human amyloid-beta (A?40 were 298 pg/ml for hemizygous and 486 pg/ml for homozygous APP21 animals. Serum A?42 levels in APP21 homozygous rats were 135 pg/ml. Immunohistochemistry in brain showed that the human APP transgene was expressed in neurons, but not in glial cells. These findings were consistent with independent examination of enhanced green fluorescent protein (eGFP in the brains of eGFP-transgenic rats. APP21 and APP31 rats expressed 7.5- and 3-times more APP mRNA, respectively, than did wild-type rats. Northern blots showed that the human APP transgene, driven by the ubiquitin-C promoter, is expressed significantly more in brain, kidney and lung compared to heart and liver. A similar expression pattern was also seen for the endogenous rat APP. The unexpected similarity in the tissue-specific expression patterns of endogenous rat APP and transgenic human APP mRNAs suggests regulatory elements within the cDNA sequence of APP. Conclusion This manuscript describes the generation of APP-transgenic inbred Fischer 344 rats. These are the first human AD model rat lines generated by lentiviral infection. The APP21 rat line expresses high levels of human APP and could be a useful model for AD. Tissue-specific expression in the two transgenic rat lines and in wild-type rats contradicts our current understanding of APP gene regulation. Determination of the elements that are responsible for tissue-specific expression of APP may enable new treatment options for AD.

Chan Anthony WS

2008-02-01

377

Serum protein profile of Crohn's disease treated with infliximab.  

Science.gov (United States)

The infliximab (IFX) has dramatically improved the treatment of Crohn's disease (CD). However, the need for predictive factors, indicative of patients' response to IFX, has yet to be met. In the current study, proteomics technologies were employed in order to monitor for differences in protein expression in a cohort of patients following IFX administration, aiming at identifying a panel of candidate protein biomarkers of CD, symptomatic of response to treatment. We enrolled 18 patients, who either had achieved clinical and serological remission (Rm, n=6), or response (Rs, n=6) and/or were PNRs (n=6), to IFX. Serum samples were subjected to two-dimensional Gel Electrophoresis. Following evaluation of densitometrical data, protein spots exhibiting differential expression among the groups, were further characterized by MALDI-TOF-MS. Identified proteins where evaluated by immunoblot analysis while functional network association was carried out to asses significance. Proteins apolipoprotein A-I (APOA1), apolipoprotein E (APOE), complement C4-B (CO4B), plasminogen (PLMN), serotransferrin (TRFE), beta-2-glycoprotein 1 (APOH), and clusterin (CLUS) were found to be up-regulated in the PNR and Rs groups whereas their levels displayed no changes in the Rm group when compared to baseline samples. Additionally, leucine-rich alpha-2-glycoprotein (A2GL), vitamin D-binding protein (VTDB), alpha-1B-glycoprotein (A1BG) and complement C1r subcomponent (C1R) were significantly increased in the serum of the Rm group. Through the incorporation of proteomics technologies, novel serum marker-molecules demonstrating high sensitivity and specificity are introduced, hence offering an innovative approach regarding the evaluation of CD patients' response to IFX therapy. PMID:23562004

Gazouli, Maria; Anagnostopoulos, Athanasios K; Papadopoulou, Aggeliki; Vaiopoulou, Anna; Papamichael, Konstantinos; Mantzaris, Gerassimos; Theodoropoulos, George E; Anagnou, Nicholas P; Tsangaris, George Th

2013-11-01

378

Inhibition of amyloid precursor protein processing enhances gemcitabine-mediated cytotoxicity in pancreatic cancer cells.  

Science.gov (United States)

Pancreatic adenocarcinoma or pancreatic cancer is often diagnosed at a very late stage at which point treatment options are minimal. Current chemotherapeutic interventions prolong survival marginally, thereby emphasizing the acute need for better treatment options to effectively manage this disease. Studies from different laboratories have shown that the Alzheimer disease-associated amyloid precursor protein (APP) is overexpressed in various cancers but its significance is not known. Here we sought to determine the role of APP in pancreatic cancer cell survival and proliferation. Our results show that pancreatic cancer cells secrete high levels of sAPP?, the ?-secretase cleaved ectodomain fragment of APP, as compared with normal non-cancerous cells. Treatment of cells with batimastat or GI254023X, inhibitors of the ?-secretase ADAM10, prevented sAPP? generation and reduced cell survival. Additionally, inhibition of sAPP? significantly reduced anchorage independent growth of the cancer cells. The effect of batimastat on cell survival and colony formation was enhanced when sAPP? downregulation was combined with gemcitabine treatment. Moreover, treatment of batimastat-treated cells with recombinant sAPP? reversed the inhibitory effect of the drug thereby indicating that sAPP? can indeed induce proliferation of cancer cells. Down-regulation of APP and ADAM10 brought about similar results, as did batimastat treatment, thereby confirming that APP processing is important for growth and proliferation of these cells. These results suggest that inhibition of sAPP? generation might enhance the effectiveness of the existing chemotherapeutic regimen for a better outcome. PMID:24022491

Woods, Neha Kabra; Padmanabhan, Jaya

2013-10-18

379

Aberrant T-lymphocyte development and function in mice overexpressing human soluble amyloid precursor protein-?: implications for autism  

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Abnormalities in T-lymphocyte populations and function are observed in autism. Soluble amyloid precursor protein ? (sAPP-?) is elevated in some patients with autism and is known to be produced by immune cells. In light of the well-established role of sAPP-? in proliferation, growth, and survival of neurons, we hypothesized an analogous role in the immune system. Thus, we explored whether sAPP-? could modulate immune development and function, especially aspects of the pinnacle cell of the ...

Bailey, Antoinette R.; Hou, Huayan; Obregon, Demian F.; Tian, Jun; Zhu, Yuyan; Zou, Qiang; Nikolic, William V.; Bengtson, Michael; Mori, Takashi; Murphy, Tanya; Tan, Jun

2012-01-01

380

Essential roles for the FE65 amyloid precursor protein-interacting proteins in brain development  

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Targeted deletion of two members of the FE65 family of adaptor proteins, FE65 and FE65L1, results in cortical dysplasia. Heterotopias resembling those found in cobblestone lissencephalies in which neuroepithelial cells migrate into superficial layers of the developing cortex, aberrant cortical projections and loss of infrapyramidal mossy fibers arise in FE65/FE65L1 compound null animals, but not in single gene knockouts. The disruption of pial basal membranes underlying the heterotopias and p...

2006-01-01

 
 
 
 
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Messenger RNAs of beta-amyloid precursor protein and prion protein are regulated by nerve growth factor in PC12 cells.  

Science.gov (United States)

The effect of the neurotrophic factor NGF on the expression of two genes involved in the accumulation of amyloid deposits in neurodegenerative disorders was studied in a clonal cell line, PC12. Use of hybridization methods showed that NGF increased the cellular pool of the mRNA of the prion protein, a macromolecule known to generate fibrillary aggregates in the brain of scrapie-infected animals. Maximal levels of prion mRNA were obtained after 7 days of treatment, but a significant increase was already detectable after 48 hr of exposure to NGF. In contrast, the factor did not increase the cellular content of the transcripts coding for the precursor of the beta-amyloid peptide (APP), which participates in the formation of neuritic plaques in human brains affected by Alzheimer's disease. However, NGF caused a drop in the molecular weight of that mRNA. This change, which is likely to result from a loss of 100-200 bp, was already detected after 24 hr of treatment. These results indicate that NGF induces in target neuronal cells a quantitative and a qualitative modification of the transcription products encoding two different amyloid precursor proteins. PMID:2903615

Wion, D; Le Bert, M; Brachet, P

1988-01-01