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1

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.

Domingos Dias Cicarelli; Joaquim Edson Vieira; Fábio Ely Martins Benseñor

2008-01-01

2

Amyloidosis and the serum amyloid A protein response to muramyl dipeptide analogs and different mycobacterial species.  

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Serum amyloid A protein (SAA) elevation accompanies induction of secondary amyloidosis in mice given Mycobacterium butyricum in Freund adjuvant. The synthesis of SAA by cultured hepatocytes is induced by a macrophage-derived mediator, which has been identified as interleukin 1. In these studies, SAA...

McAdam, K P; Foss, N T; Garcia, C; DeLellis, R; Chedid, L; Rees, R J; Wolff, S M

3

Serum amyloid-A protein and serum rheumatoid factor as serological surrogate markers for smoking risk factor in Saudi population.  

UK PubMed Central (United Kingdom)

Tobacco smoking represents major national and international health hazard that interferes with wide range of physiological functions and biomarkers. In the current study we have investigated the influence of tobacco smoking on some biological markers such as serum amyloid protein-A, rheumatoid factor, serum glucose level and lipid profile in Saudi population. The fore mentioned parameters were investigated in a total of 275 cases in 3 different age categories (less than 20 years old, 20-40 years old and older than 40 years old). Long term survey was adopted in all cases; yet, lightly smoking and heavily smoking groups were compared to never smoking healthy population. Results obtained showed significant increase in serum amyloid protein-A and rheumatoid factor in correlation to the degree of smoking nonetheless in the age category older than 40 years old. Serum glucose, triglyceride, and total cholesterol was not affected by smoking in all studied age categories; however serum LDL-cholesterol was elevated and serum HDL-cholesterol was depressed in correlation to the degree of smoking in all age categories. In conclusion, tobacco smoking represents major cardiovascular risk factor in Saudi population in all age categories and serum amyloid protein-A and rheumatoid factor might be used as a serological surrogate marker for such risk.

Al-Sieni AI; Al-Alawy AI; Al-Shehri ZS; Al-Abbasi FA

2013-03-01

4

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

International Nuclear Information System (INIS)

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

5

Feline serum amyloid A protein as an endogenous Toll-like receptor 4 agonist.  

Science.gov (United States)

Serum amyloid A (SAA) is one of the major acute phase proteins and a biomarker of infection or inflammation in humans and cats. In humans, cytokine-like functions of SAA protein have been determined, and SAA is considered to be an important factor in immune responses. However, there are no reports about the functions of SAA protein in cats. In the present study, the functions of feline SAA protein on peripheral monocytes were investigated by using TNF-? production as an indicator. In feline peripheral blood monocytes, SAA protein stimulated the transcription of TNF-? within 2h and induced TNF-? secretion in time- and dose-dependent manners. The production of TNF-? by SAA stimulation in feline monocytes was found to be mediated by the activation of nuclear factor-kappa B (NF-?B). Moreover, SAA-stimulated TNF-? production was prevented by a Toll-like receptor 4 (TLR4) antagonist. On the basis of these results, feline SAA was demonstrated to be an endogenous agonist of TLR4 for the stimulation of TNF-? production and secretion by peripheral monocytes. These results suggest that feline SAA can play an important role in the regulation of inflammation and immune responses as it does in humans. PMID:23942262

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

2013-06-19

6

Feline serum amyloid A protein as an endogenous Toll-like receptor 4 agonist.  

UK PubMed Central (United Kingdom)

Serum amyloid A (SAA) is one of the major acute phase proteins and a biomarker of infection or inflammation in humans and cats. In humans, cytokine-like functions of SAA protein have been determined, and SAA is considered to be an important factor in immune responses. However, there are no reports about the functions of SAA protein in cats. In the present study, the functions of feline SAA protein on peripheral monocytes were investigated by using TNF-? production as an indicator. In feline peripheral blood monocytes, SAA protein stimulated the transcription of TNF-? within 2h and induced TNF-? secretion in time- and dose-dependent manners. The production of TNF-? by SAA stimulation in feline monocytes was found to be mediated by the activation of nuclear factor-kappa B (NF-?B). Moreover, SAA-stimulated TNF-? production was prevented by a Toll-like receptor 4 (TLR4) antagonist. On the basis of these results, feline SAA was demonstrated to be an endogenous agonist of TLR4 for the stimulation of TNF-? production and secretion by peripheral monocytes. These results suggest that feline SAA can play an important role in the regulation of inflammation and immune responses as it does in humans.

Tamamoto T; Ohno K; Goto-Koshino Y; Tsujimoto H

2013-09-01

7

Waldenstrom's Macroglobulinemia Associated with Serum Amyloid A Protein Amyloidosis: Pitfalls in Diagnosis and Successful Treatment with Melphalan-Based Autologous Stem Cell Transplant.  

UK PubMed Central (United Kingdom)

Waldenström's macroglobulinemia (WM) is increasingly being associated with amyloidosis particularly of the amyloid light-chain variety. We report on one of the few cases of WM associated with serum amyloid A protein (AA) amyloidosis. Autologous stem cell transplant (ASCT) is now being increasingly used for the treatment of amyloidosis, but most studies are small case series. Traditionally AA amyloid is associated with connective tissue disorders and periodic fever syndromes and has been treated by addressing the underlying condition. We present the first case of serum amyloid A being treated with melphalan-based ASCT to deal with the underlying WM and thereby control the amyloid, thus demonstrating the viability of this novel approach for the treatment of this disorder.

Muzaffar J; Katragadda L; Haider S; Abdallah AO; Anaissie E; Usmani SZ

2013-05-01

8

Detection of high-molecular-weight amyloid serum protein complexes using biological on-line tracer sedimentation.  

UK PubMed Central (United Kingdom)

The systemic amyloidoses are a rare but deadly class of protein folding disorders with significant unmet diagnostic and therapeutic needs. The current model for symptomatic amyloid progression includes a causative role for soluble toxic aggregates as well as for the fibrillar tissue deposits. Although much research is focused on elucidating the potential mechanism of aggregate toxicity, evidence to support their existence in vivo has been limited. We report the use of a technique we have termed biological on-line tracer sedimentation (BOLTS) to detect abnormal high-molecular-weight complexes (HMWCs) in serum samples from individuals with systemic amyloidosis due to aggregation and deposition of wild-type transthyretin (senile systemic amyloidosis, SSA) or monoclonal immunoglobulin light chain (AL amyloidosis). In this proof-of-concept study, HMWCs were observed in 31 of 77 amyloid samples (40.3%). HMWCs were not detected in any of the 17 nonamyloid control samples subjected to BOLTS analyses. These findings support the existence of potentially toxic amyloid aggregates and suggest that BOLTS may be a useful analytic and diagnostic platform in the study of the amyloidoses or other diseases where abnormal molecular complexes are formed in serum.

Kingsbury JS; Laue TM; Chase SF; Connors LH

2012-06-01

9

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

10

Expression of the protein serum amyloid A (SAA) in response to Aspergillus fumigatus in murine models of allergic airway inflammation.  

UK PubMed Central (United Kingdom)

BACKGROUND: Serum amyloid A (SAA) is an acute phase protein that is elevated in blood during inflammation. The role of this protein in allergic diseases of airways remains unclear. AIMS: The objective of this study was to evaluate the SAA in blood, lung and bronchial cells in a murine model of bronchial hypersensitivity to Aspergillus fumigatus. METHODS: To achieve this purpose, different groups of 5-month-old mice were housed in cages containing hay bedding that was contaminated with A. fumigatus and were kept in an isolation room for 16 days to allow for the induction of allergic airway inflammation. Subsequently, the mice were then exposed once again to Aspergillus spores at 0, 2, 8, 24 and 72hours, mice were bled to acquire serum and sacrificed to obtain bronchoalveolar lavage fluid (BALF) or lung tissues for analysis. SAA levels were measured in lung, serum and BALF by dot blot assay and RT-PCR (reverse transcription polymerase chain reaction). RESULTS: The results indicated that SAA protein levels increased in both serum and lung within 2-24hours after mice were exposed to Aspergillus spores. Moreover, the SAA mRNA expression levels in the lungs and BALF cells demonstrated the same trend that was observed for the protein levels through the dot blot assay; in particular, SAA mRNA levels increased within the first hour after mice were exposed to A. fumigatus. CONCLUSIONS: In this allergic airway model, we conclude that A. fumigatus can induce an acute inflammatory response in the airways through the stimulation of the SAA protein, increasing its levels in serum, lung tissue and BALF samples during the early hours of exposure of mice that have been sensitized for this fungus.

Moran G; Carcamo C; Concha M; Folch H

2013-04-01

11

Rapid recycling of cholesterol: the joint biologic role of C-reactive protein and serum amyloid A.  

UK PubMed Central (United Kingdom)

Proteins that are highly conserved throughout evolution are presumed to have critical roles in the survival of the species. The two major acute phase proteins, C-reactive protein (CRP) and serum amyloid A (SAA) increase up to 1000-fold during inflammation. Both proteins have been highly conserved phylogenetically for at least the last 500 million years. Thus far the physiologic role and the evolutionary significance of each remains uncertain and their potential interactions have been totally ignored despite a vast and accelerating scientific literature on the involvement of each in human disease. CRP is known to bind to phosphocholine in dead eukaryote and some live bacterial cell walls suggesting that CRP facilitates the phagocytosis of fragmented or intact dead cells and/or enhances host bacterial defenses. SAA has recently been shown to increase the rate of export of cholesterol of phagocytosed cell membranes from macrophages fourfold. We postulate that their combined physiological role is to facilitate the rapid endogenous recycling of cell membrane cholesterol and phospholipids during acute inflammation. CRP promotes efficient phagocytosis of dying cells by macrophages; SAA enhances the export of their free cholesterol/phospholipid for reuse in the membranes of the hundreds of billions of new cells required daily during acute inflammation and repair. The evolutionary conservation of these proteins in species from the horseshoe crab and echinoderms to humans suggests that the rapid endogenous recycling of cholesterol and phospholipids during the highly vulnerable period of acute inflammation is critical for their continual survival.

Manley PN; Ancsin JB; Kisilevsky R

2006-01-01

12

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

UK PubMed Central (United Kingdom)

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 HCC, a dysplastic nodule, an inflammatory pseudotumor or focal nodular hyperplasia (FNH). US-guided biopsy in S2 showed minimal atypical changes, except for a slight increase in cell density, and micronodular cirrhosis in the non-nodular portion. Gd-EOB-DTPA-enhanced MRI 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 might be explained more by the weak OATP8 staining compared with that of alcohol-related liver cirrhosis than by malignant transformation into HCC.

Kim SR; Kondo F; Otono Y; Imoto S; Ando K; Hirakawa M; Fukuda K; Sakaki M; Kim SK; Komaki T; Tsuchida S; Kobayashi S; Matsuoka T; Kudo M

2013-04-01

13

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

International Nuclear Information System (INIS)

[en] 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

14

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

Science.gov (United States)

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

2013-04-23

15

The amyloid precursor protein: beyond amyloid  

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

Zheng Hui; Koo Edward H

2006-01-01

16

Effects of calcium, magnesium, and phosphorylcholine on secondary structures of human C-reactive protein and serum amyloid P component observed by infrared spectroscopy.  

UK PubMed Central (United Kingdom)

The secondary structures of human C-reactive protein (CRP) and serum amyloid P component (SAP) in D2O-based solutions in the presence or absence of calcium, magnesium, and phosphorylcholine have been investigated using Fourier transform infrared spectroscopy. Quantitative analysis provided estimations of about 50% beta-sheet, 12% alpha-helix, 24% beta-turn, and 14% unordered structure for CRP and about 54% beta-sheet, 12% alpha-helix, 25% beta-turn, and 9% unordered structure for SAP. With both proteins significant calcium-dependent changes were observed in conformation-sensitive amide I regions assigned to each type of structure. The CRP spectrum was also affected by magnesium, but the changes differed from those induced by calcium. The SAP spectrum was not affected by magnesium. Phosphorylcholine in the presence of calcium also affected the spectrum of CRP but not the spectrum of SAP. Our present study provides the first direct comparison of the secondary structures of the pentraxins human CRP and SAP and hamster female protein (Dong, A., Caughey, B., Caughey, W. S., Bhat, K. S., and Coe, J. E. (1992) Biochemistry 32, 9364-9370). These findings suggest that the three pentraxins have similar secondary structure compositions and calcium-dependent conformational changes, but differ significantly in their responses to phosphorylcholine and magnesium. Such properties are expected to be relevant to the incompletely understood roles of these highly conserved proteins including binding to nuclear proteins, complement activation, and association with amyloids.

Dong A; Caughey WS; Du Clos TW

1994-03-01

17

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

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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 {sup 123}I-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, {sup 123}I-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.) With 2 figs., 2 tabs., 22 refs.

Rydh, A.; Hietala, S.O.; Aahlstroem, K.R. [Department of Diagnostic Radiology, University Hospital of Northern Sweden, Umeaa (Sweden); Suhr, O. [Department of Internal Medicine, University Hospital of Northern Sweden, Umeaa (Sweden); Pepys, M.B.; Hawkins, P.N. [Immunological Medicine Unit, Department of Medicine, Imperial College School of Medicine, London (United Kingdom)

1998-07-01

18

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.)

1998-01-01

19

Localization of four human serum amyloid A (SAA) protein superfamily genes to chromosome 11p: Characterization of a fifth SAA-related gene sequence  

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The serum amyloid A proteins (SAAs) are heterogeneous differentially expressed apolipoproteins of M[sub r] 12-19 kDa. Four SAA loci have been described. Two of the loci (SAA1 and SAA2) encode acute-phase SAAs (A-SAAs), which exhibit a dramatic transient increase in serum concentration in response to inflammatory stimuli; a third locus (SAA3) defines a pseudogene; and a fourth locus (SAA4) encodes a constitutively expressed SAA (C-SAA). Using locus-specific polymerase chain reaction, the authors have definitively assigned all four well-characterized SAA loci, SAA1, -2, -3, and -4, to chromosome 11p. In addition, they have more fully characterized an ill-defined sequence previously misidentified by others as SAA4, which also maps to chromosome 11p and may represent a fifth SAA locus. 17 refs., 3 figs.

Sellar, G.C.; Whitehead, A.S. (Trinity College, Dublin (Ireland))

1993-06-01

20

Serum amyloid A and C-reactive protein concentrations are differently associated with markers of autoimmunity in patients with primary Sjogren's syndrome.  

UK PubMed Central (United Kingdom)

OBJECTIVE: Primary Sjögren's syndrome (pSS) is an autoimmune disease in which the concentration of the acute-phase protein serum C-reactive protein (CRP) is low. We investigated whether levels of another acute-phase protein, serum amyloid A (SAA), are increased in patients with pSS and whether the immunological markers in patients with pSS are associated with variation in SAA levels. METHODS: Serum SAA concentrations were measured by ELISA in 74 patients with pSS and in 56 control subjects with sicca symptoms. RESULTS: Median SAA levels did not differ significantly between patients with pSS and subjects with sicca symptoms. In patients with pSS SAA concentrations correlated significantly with age, leukocyte count, CRP, interleukin 6, and C4. Unlike CRP, there was a significant inverse correlation between SAA and serum IgG levels and anti-SSA antibody titers, as well as a trend towards an inverse correlation between SAA and antinuclear antibody and rheumatoid factor titers. CONCLUSION: Our data imply that high SAA production could constitute a protective element in pSS: high SAA levels inhibit in particular various signs of B cell hyperreactivity, i.e., IgG and autoantibody production.

Pertovaara M; Jylhävä J; Uusitalo H; Pukander J; Helin H; Hurme M

2009-11-01

 
 
 
 
21

A constitutively expressed serum amyloid A protein gene (SAA4) is closely linked to, and shares structural similarities with, an acute-phase serum amyloid A protein gene (SAA2)  

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The acute-phase reactant serum amyloid A (SAA) is a polymorphic apolipoprotein encoded by a family of highly homologous and closely linked genes: SAA1, SAA2, and SAA3. The authors have isolated a human genomic cosmid clone containing the gene encoding a fourth, constitutively expressed member of the human SAA superfamily, C-SAA, together with an SAA2*2 (SAA2{beta}) gene. The gene encoding C-SAA shares the same 5{prime} to 3{prime} orientation as SAA2*2 and has the characteristic four-exon structure of the other members of the SAA superfamily. The exons of the gene encoding C-SAA share only limited sequence identity with those of SAA1, SAA2, and SAA3; they specify an mRNA, represented by the CS-1 cDNA reported previously, which is expressed at low levels (relative to the acute-phase SAAs) in normal and acute-phase liver. The gene encoding C-SAA is located 9 kb downstream of SAA2*2 and therefore occupies the locus that has been identified as containing the SAA4 gene. 35 refs., 3 figs., 1 tab.

Steel, D.M.; Sellar, G.C.; Uhlar, C.M.; Whitehead, A.S. [Univ. of Dublin (Ireland); Simon, S. [Center for Blood Research, Boston, MA (United States); DeBeer, F.C. [Univ. of Kentucky Medical Center, Lexington, KY (United States)

1993-05-01

22

Search for amyloid-binding proteins by affinity chromatography.  

UK PubMed Central (United Kingdom)

'Amyloid binging proteins' is a generic term used to designate proteins that interact with different forms of amyloidogenic peptides or proteins and that, as a result, may modulate their physiological and pathological functions by altering solubility, transport, clearance, degradation, and fibril formation. We describe a simple affinity chromatography protocol to isolate and characterize amyloid-binding proteins based on the use of sequential elution steps that may provide further information on the type of binding interaction. As an example, we depict the application of this protocol to the study of Alzheimer's amyloid ? (A?) peptide-binding proteins derived from human plasma. Biochemical analysis of the proteins eluted under different conditions identified serum amyloid P component (SAP) and apolipoprotein J (clusterin) as the main plasma A?-binding proteins while various apolipoproteins (apoA-IV, apoE, and apoA-I), as well as albumin (HSA) and fibulin were identified as minor contributors.

Calero M; Rostagno A; Ghiso J

2012-01-01

23

Proteolytic Degradation of Amyloid ?-Protein  

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The amyloid ?-protein (A?) is subject to proteolytic degradation by a diverse array of peptidases and proteinases, known collectively as A?-degrading proteases (A?DPs). A growing number of A?DPs have been identified, which, under physiological and/or pathophysiological conditions, contribute signifi...

Saido, Takaomi; Leissring, Malcolm A.

24

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.  

UK PubMed Central (United Kingdom)

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 35days, 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 21dpi, while the concentration of alpha-1 acid glycoprotein (AGP) was lower at 35dpi, 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 21dpi 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.

Lv Y; Zhang X; Sun Y; Zhang S

2013-08-01

25

Serum amyloid P component accelerates the formation and enhances the stability of amyloid fibrils in a physiologically significant under-saturated solution of amyloid-?42.  

UK PubMed Central (United Kingdom)

The mechanism whereby an under-saturated solution of amyloid-? (A?)42 precipitates as ? sheets in vivo in Alzheimer's disease remains to be elucidated. Herein we present in vitro evidence that serum amyloid P component may mediate this process through its acceleration of amyloid formation from an under-saturated solution of A?42 and subsequently its stabilization of the amyloid fibrils formed over physiologically significant timeframes. Our observations support serum amyloid P component as a therapeutic target in Alzheimer's disease.

Mold M; Shrive AK; Exley C

2012-01-01

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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

27

Acute-phase serum amyloid A protein and its implication in the development of type 2 diabetes in the KORA S4/F4 study.  

UK PubMed Central (United Kingdom)

OBJECTIVE: We sought to investigate whether elevated levels of acute-phase serum amyloid A (A-SAA) protein precede the onset of type 2 diabetes independently of other risk factors, including parameters of glucose metabolism. RESEARCH DESIGN AND METHODS: Within the population-based Cooperative Health Research in the Region of Augsburg (KORA) S4 study, we measured A-SAA concentrations in 836 initially nondiabetic subjects (55-74 years of age) without clinically overt inflammation who participated in a 7-year follow-up examination including an oral glucose tolerance test. RESULTS: A-SAA concentrations were significantly associated with incident type 2 diabetes (odds ratio [OR] for a one-SD increase of A-SAA adjusted for age and sex = 1.28 [95% CI 1.08-1.53], P = 0.005), particularly in younger subjects (P value for interaction = 0.047). The association attenuated when adjusting for parameters of glucose metabolism (fasting glucose, fasting insulin, HbA1c, and 2-h glucose; OR 1.16 [0.95-1.42], P = 0.15). Similar analyses for high-sensitive C-reactive protein (hs-CRP) yielded the following ORs: 1.39 (1.10-1.68, P = 0.0006) and 1.13 (0.88-1.45, P = 0.34), respectively. In contrast, A-SAA concentrations were significantly associated with 2-h glucose levels at follow-up even after adjustment for parameters of glucose metabolism (P = 0.008, n = 803). CONCLUSIONS: Our findings indicate similarly strong prospective associations with type 2 diabetes for A-SAA and hs-CRP and suggest a potential causal link via postchallenge hyperglycemia.

Marzi C; Huth C; Herder C; Baumert J; Thorand B; Rathmann W; Meisinger C; Wichmann HE; Roden M; Peters A; Grallert H; Koenig W; Illig T

2013-05-01

28

Serum amyloid A and C-reactive protein levels may predict microalbuminuria and macroalbuminuria in newly diagnosed type 1 diabetic patients.  

UK PubMed Central (United Kingdom)

BACKGROUND: In this study we evaluated the association of baseline levels of six different candidate proteins for the development of microalbuminuria and macroalbuminuria in type 1 diabetic patients, who were followed for approximately 30 years. Two of the proteins are markers of inflammation: serum amyloid A (SAA) and C-reactive protein (CRP), three are involved in lipid metabolism: apolipoprotein A1, apolipoprotein E and adiponectin and the last protein, fibronectin, is related to structural changes. METHODS: A nested case control study population of 60 patients from an inception cohort of type 1 diabetic patients where 20 developed microalbuminuria followed by macroalbuminuria and 40 stayed normoalbuminuric during approximately 30 years of follow-up time was used to evaluate baseline levels of the six candidate biomarkers. The proteins were quantified by multiplexed immunoassays. RESULTS: Log SAA levels were borderline predictor of microalbuminuria, HR 2.31 (1-5.4) p=0.053 in a univariate Cox regression model and predicted the development of macroalbuminuria HR 2.432 (1-6) p=0.049, also univariate. When adjusting for covariates, log SAA predicted the development of microalbuminuria with an HR 4.131 (1.1-15) p=0.03. Log CRP predicted the development of microalbuminuria, HR 2.928 (1.4-6.1) p=0.004, and macroalbuminuria, HR 2.785 (1.3-5.8) p=0.007 in univariate models. When adjusting for covariates, log CRP predicted the development of microalbuminuria with an HR 5.882 (1.7-20.9) p=0.006 and macroalbuminuria with an HR 3.233 (1.1-9.8) p=0.038. Apolipoprotein A1, apolipoprotein E, fibronectin and adiponectin were not associated with development of elevated albumin excretion rate. CONCLUSIONS: SAA and CRP baseline levels predicted development of micro- and macroalbuminuria during 30 years of follow up, supporting the theory that inflammation is involved in the progression of diabetic nephropathy. Further studies are needed to fully establish the two proteins' potential as additional biomarkers for the development of diabetic nephropathy.

Overgaard AJ; McGuire JN; Hovind P; Parving HH; Rossing P; Pociot F

2013-01-01

29

Transthyretin sequesters amyloid beta protein and prevents amyloid formation  

DEFF Research Database (Denmark)

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

Schwarzman, A L; Gregori, L

1994-01-01

30

Serum Amyloid A Circulating Levels and Disease Activity in Patients with Juvenile Idiopathic Arthritis  

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The aim of our study was to evaluate the association between circulating levels of serum amyloid A protein (SAA) and disease activity in patients with juvenile idiopathic arthritis (JIA). Our study group included 41 JIA patients (9 male, 32 female), classified according to the International League o...

Cantarini, Luca; Giani, Teresa; Fioravanti, Antonella; Iacoponi, Francesca; Simonini, Gabriele; Pagnini, Ilaria

31

Inflammatory markers at the site of ruptured plaque in acute myocardial infarction: locally increased interleukin-6 and serum amyloid A but decreased C-reactive protein.  

UK PubMed Central (United Kingdom)

BACKGROUND: Acute myocardial infarction (AMI) is associated with inflammation. However, it remains unclear whether it originates from the ruptured plaque or represents a systemic process. METHODS AND RESULTS: In 42 patients with AMI, a balloon-based embolization protection device and aspiration catheter (PercuSurge) were used during acute coronary interventions. Samples from the site of the ruptured plaque were taken under distal balloon occlusion. Systemic samples were taken from the aorta. Sera, plaques, and thrombi were analyzed for inflammatory markers and lipoproteins. Systemic levels of C-reactive protein (CRP), interleukin-6 (IL-6), and serum amyloid A (SAA) in the aorta amounted to 3.0 mg/L, 5.0 ng/L, and 22.1 mg/L, respectively (interquartile ranges [IQRs], 1.1 to 7.4 mg/L, 5.0 to 6.5 ng/L, and 13.9 to 27.0 mg/L, respectively). In blood surrounding ruptured plaques, local levels of IL-6 (8.9 ng/L; IQR, 5.0 to 16.9 ng/L) and SAA (24.3 mg/L; IQR, 16.3 to 44.0 mg/L) were significantly higher, whereas CRP levels (2.5 mg/L; IQR, 0.9 to 7.7 mg/L) were decreased compared with the aorta (all P<0.0001). The coronary levels of IL-6 determined in vivo showed biological activity in vitro. Harvested thrombus contained CD68-positive monocytes expressing IL-6 and showed extracellularly and intracellularly positive staining for SAA, whereas CRP was found exclusively in the cytoplasm of phagocyting white blood cells. CONCLUSIONS: Coronary levels of IL-6 and SAA at the site of plaque rupture were increased relative to the systemic circulation, indicating local production of biologically active inflammatory mediators. In contrast, CRP was locally decreased, at least in part by uptake by the phagocyting cells, suggesting a systemic origin of the protein.

Maier W; Altwegg LA; Corti R; Gay S; Hersberger M; Maly FE; Sütsch G; Roffi M; Neidhart M; Eberli FR; Tanner FC; Gobbi S; von Eckardstein A; Lüscher TF

2005-03-01

32

Serum amyloid A isoforms in serum and synovial fluid from spontaneously diseased dogs with joint diseases or other conditions  

DEFF Research Database (Denmark)

Serum amyloid A (SAA) is a major acute phase protein in dogs. However, knowledge of qualitative properties of canine SAA and extent of its synthesis in extrahepatic tissues is limited. The aim of the study was to investigate expression of different SAA isoforms in serum and synovial fluid in samples obtained from dogs (n = 16) suffering from different inflammatory or non-inflammatory conditions, which were either related or unrelated to joints. Expression of SAA isoforms was visualized by denaturing isoelectric focusing and Western blotting. Serum amyloid A was present in serum from all dogs with systemic inflammatory activity, and up to four major isoforms with apparent isoelectric points between 6.1 and 7.9 were identified. In synovial fluid from inflamed joints one or more highly alkaline SAA isoforms (with apparent isoelectric points above 9.3) were identified, with data suggesting local production of these isoforms in the canine inflamed joint.

Kjelgaard-Hansen, Mads Jens; Christensen, Michelle B.

2007-01-01

33

The human serum amyloid A protein (SAA) superfamily gene cluster: Mapping to chromosome 11p15. 1 by physical and genetic linkage analysis  

Energy Technology Data Exchange (ETDEWEB)

The human serum amyloid A protein (SAA) family comprises a number of small, hepatically produced, differentially expressed apolipoproteins encoded by genes localized on the short arm of chromosome 11. SAA1 and SAA2 are highly related genes that together encode the acute-phase SAAs; SAA3 is a pseudogene; and SAA4 is a low-level constitutively expressed gene encoding constitutive SAA. The authors have used a combination of physical and genetic mapping techniques to provide evidence that the SAA gene superfamily comprises a cluster of closely linked genes localized to 11p15.1. Pulsed-field gel electrophoresis placed SAA 1 to within 350 kb of the previously linked SAA2 and SAA4 genes. SAA locus-specific polymerase chain reaction amplification from a panel of somatic cell hybrids carrying defined regions of chromosome 11p mapped all four loci to 11p15.1pter. Fluorescence in situ hybridization analysis using a cosmid probe carrying the SAA2 and SAA4 genes refined the localization of these genes (and SAA1) to 11p15.1. To order SAA3 on the genetic map, a highly polymorphic (CA)[sub n] dinucleotide repeat within SAA3 was typed through the CEPH reference families. In accordance with the physical localization of SAAs 1, 2, and 4, SAA3 maps to the 11p15.1 region proximal to the parathyroid hormone (PTH) locus ([theta] = 0.02; lod = 12.020) and distal to D11S455 ([theta] = 0.058, lod = 8.274). To provide further evidence of an SAA superfamily gene cluster, an NcoI restriction fragment length polymorphism in the SAA2 gene was also typed through the CEPH reference panel. Two-point lod score analysis gave [theta] = 0.001, with lod = 10.82 between SAA3 and SAA2, thereby firmly confirming close linkage between all known SAA superfamily members on chromosome 11p15.1. 41 refs., 4 figs., 1 tab.

Sellar, G.C.; Jordan, S.A.; Whitehead, A.S. (Univ. of Dublin (Ireland)); Bickmore, W.A.; Fantes, J.A.; Van Heyningen, V. (Western General Hospital, Edinburgh (United Kingdom))

1994-01-15

34

Ligand-binding sites in human serum amyloid P component  

DEFF Research Database (Denmark)

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

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

1996-01-01

35

Soluble amyloid precursor protein-? modulates ?-secretase activity and amyloid-? generation.  

UK PubMed Central (United Kingdom)

In sporadic age-related forms of Alzheimer's disease (AD), it is unclear why amyloid-? (A?) peptides accumulate. Here we show that soluble amyloid precursor protein-? (sAPP-?) decreases A? generation by directly associating with ?-site APP-converting enzyme (BACE)1, thereby modulating APP processing. Whereas specifically targeting sAPP-? using antibodies enhances A? production; in transgenic mice with AD-like pathology, sAPP-? overexpression decreases ?-amyloid plaques and soluble A?. In support, immunoneutralization of sAPP-? increases APP amyloidogenic processing in these mice. Given our current findings, and because a number of risk factors for sporadic AD serve to lower levels of sAPP-? in brains of AD patients, inadequate sAPP-? levels may be sufficient to polarize APP processing towards the amyloidogenic, A?-producing route. Therefore, restoration of sAPP-? or enhancement of its association with BACE may be viable strategies to ameliorate imbalances in APP processing that can lead to AD pathogenesis.

Obregon D; Hou H; Deng J; Giunta B; Tian J; Darlington D; Shahaduzzaman M; Zhu Y; Mori T; Mattson MP; Tan J

2012-01-01

36

Cloning and quantification of ferret serum amyloid A.  

UK PubMed Central (United Kingdom)

Serum amyloid A (SAA) is used as a biomarker for infections and inflammation in humans and veterinary medicine. We cloned ferret cDNA encoding SAA from the liver of a ferret via reverse transcription PCR (RT-PCR). The sequence of the cDNA clone revealed that ferret SAA has an open reading frame of 387 bp that encodes 129 amino acids. The deduced amino acid sequence of ferret SAA has 96.1, 89.9, 86.0, 83.8, 83.0, 73.8 and 65.3% similarity to the mink, dog, cat, cattle, horse, human and mouse SAA genes, respectively. Compared to human SAA, the deduced ferret SAA amino acid sequence had an insertion of an 8-amino acid fragment between amino acids 88 and 95. Recombinant ferret SAA (rfrSAA) was expressed using an Escherichia coli (E. coli) strain, BL21 Star. Using Western blot analysis, anti-SAA mAb provided with the multispecies SAA ELISA kit reacted with purified rfrSAA. A significant dose-response relationship was observed between the rfrSAA protein and a commercial multispecies SAA ELISA kit. In contrast, rfrSAA was not recognized with the antibodies included in a commercial human SAA ELISA kit. These results suggest that the structure of ferret SAA is antigenically similar to other domestic animal SAAs, and the multispecies ELISA kit allows for the detection and quantification of ferret SAA in vivo.

Aratani H; Segawa T; Itou T; Sakai T

2013-01-01

37

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; Markowska-Daniel Iwona; Kwit Krzysztof; St?pniewska Katarzyna; Pejsak Zygmunt

2013-01-01

38

Detergency effects of nanofibrillar amyloid formation on glycation of human serum albumin.  

Science.gov (United States)

The prolonged glycation of human serum albumin (HSA) results in significant changes in its structure. The identity of these structural changes and the influence of carbohydrates on these changes require further study. Here, we evaluated structural changes and amyloid formation of HSA upon incubation with Glc, Fru, or Rib. Fluorescence spectrophotometry, surface tension analysis, and transmission electron microscopy (TEM) were utilized to evaluate the structures of glycated HSA. The physicochemical properties including excess free energy, protein adsorption at the air-water interface, critical aggregation concentration (CAC), and surface activity indicated an increase in hydrophobicity and partial unfolding of HSA structure upon glycation. Thus, it appears that AGE products can act as detergents. Incubation of HSA with these sugars after 20 wks induced significant amyloid nanofibril formation. Together these results indicate that prolonged glycation of HSA is associated with a transition from helical structure to beta-sheet (amyloid formation). PMID:18513709

Sattarahmady, Naghmeh; Moosavi-Movahedi, Ali A; Habibi-Rezaei, Mehran; Ahmadian, Shahin; Saboury, Ali A; Heli, Hossein; Sheibani, Nader

2008-05-07

39

S100A12 suppresses pro-inflammatory, but not pro-thrombotic functions of serum amyloid A.  

UK PubMed Central (United Kingdom)

S100A12 is elevated in the circulation in patients with chronic inflammatory diseases and recent studies indicate pleiotropic functions. Serum amyloid A induces monocyte cytokines and tissue factor. S100A12 did not stimulate IL-6, IL-8, IL-1? or TNF-? production by human peripheral blood mononuclear cells but low amounts consistently reduced cytokine mRNA and protein levels induced by serum amyloid A, by ?49% and ?46%, respectively. However, S100A12 did not affect serum amyloid A-induced monocyte tissue factor. In marked contrast, LPS-induced cytokines or tissue factor were not suppressed by S100A12. S100A12 did not alter cytokine mRNA stability or the cytokine secretory pathway. S100A12 and serum amyloid A did not appear to form complexes and although they may have common receptors, suppression was unlikely via receptor competition. Serum amyloid A induces cytokines via activation of NF-?B and the MAPK pathways. S100A12 reduced serum amyloid A-, but not LPS-induced ERK1/2 phosphorylation to baseline. It did not affect JNK or p38 phosphorylation or the NF-?B pathway. Reduction in ERK1/2 phosphorylation by S100A12 was unlikely due to changes in intracellular reactive oxygen species, Ca(2+) flux or to recruitment of phosphatases. We suggest that S100A12 may modulate sterile inflammation by blunting pro-inflammatory properties of lipid-poor serum amyloid A deposited in chronic lesions where both proteins are elevated as a consequence of macrophage activation.

Chung YM; Goyette J; Tedla N; Hsu K; Geczy CL

2013-01-01

40

S100A12 suppresses pro-inflammatory, but not pro-thrombotic functions of serum amyloid A.  

Science.gov (United States)

S100A12 is elevated in the circulation in patients with chronic inflammatory diseases and recent studies indicate pleiotropic functions. Serum amyloid A induces monocyte cytokines and tissue factor. S100A12 did not stimulate IL-6, IL-8, IL-1? or TNF-? production by human peripheral blood mononuclear cells but low amounts consistently reduced cytokine mRNA and protein levels induced by serum amyloid A, by ?49% and ?46%, respectively. However, S100A12 did not affect serum amyloid A-induced monocyte tissue factor. In marked contrast, LPS-induced cytokines or tissue factor were not suppressed by S100A12. S100A12 did not alter cytokine mRNA stability or the cytokine secretory pathway. S100A12 and serum amyloid A did not appear to form complexes and although they may have common receptors, suppression was unlikely via receptor competition. Serum amyloid A induces cytokines via activation of NF-?B and the MAPK pathways. S100A12 reduced serum amyloid A-, but not LPS-induced ERK1/2 phosphorylation to baseline. It did not affect JNK or p38 phosphorylation or the NF-?B pathway. Reduction in ERK1/2 phosphorylation by S100A12 was unlikely due to changes in intracellular reactive oxygen species, Ca(2+) flux or to recruitment of phosphatases. We suggest that S100A12 may modulate sterile inflammation by blunting pro-inflammatory properties of lipid-poor serum amyloid A deposited in chronic lesions where both proteins are elevated as a consequence of macrophage activation. PMID:23638054

Chung, Yuen Ming; Goyette, Jesse; Tedla, Nicodemus; Hsu, Kenneth; Geczy, Carolyn L

2013-04-24

 
 
 
 
41

Evaluation of goose serum amyloid a acute phase response by enzyme-linked immunosorbent assay.  

UK PubMed Central (United Kingdom)

Serum amyloid A (SAA) is of interest as the circulating precursor of amyloid A protein, the fibrillar component of AA (secondary) amyloid deposits, and also as an extremely sensitive and rapid major acute phase protein. Serum concentrations of acute phase proteins (APPs) provide valuable information about the diagnosis and prognosis of various diseases, and thus the relevance of APPs for monitoring the health status of domestic animals is widely accepted. More importantly, the measurement of SAA concentration assists in assessing the prognosis in secondary amyloidosis, which is a common disease of geese, affecting an increasing number of animals. In the present study we introduce a highly sensitive goose-specific ELISA method for measuring SAA concentration in goose serum or plasma samples. Samples were taken from geese of the Landes Grey and Hungarian White breeds, which were stimulated for an acute phase reaction by administration of a commercially available fowl cholera vaccine containing inactivated Pasteurella multocida. Strong and characteristically rapid acute phase responses were measured in both breeds, peaking at approximately 24 h after inoculation. The maximum SAA concentration was 1200 microg/ml. At 72 h postinoculation, the concentrations returned to pre-inoculation values. There was significantly (p = 0.004) less intense response in the control groups; however, a very mild increase of SAA levels was detected due to the stress inevitably caused by the sampling procedure.

Kovács BM; Toussaint MJ; Gruys E; Fábián IB; Szilágyi L; Janan J; Rudas P

2007-09-01

42

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

43

What is the role of amyloid precursor protein dimerization?  

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Extensive research efforts have been conducted over the past decades to understand the processing of the Amyloid Precursor Protein (APP). APP cleavage leads to the production of the beta-amyloid peptide (Abeta), which is the major constituent of the amyloid core of senile plaques found in the brains...

Khalifa, Naouel Ben; Van Hees, Joanne; Tasiaux, Bernadette; Huysseune, Sandra; Smith, Steven O.; Constantinescu, Stefan

44

Steady turnover of amyloid fibril proteins in gastric mucosa after liver transplantation in familial amyloid polyneuropathy.  

Science.gov (United States)

Abstract Introduction: Our previous study demonstrated marked regression of amyloid deposits in abdominal fat tissues of familial amyloid polyneuropathy (FAP) patients treated with liver transplantation (LT). To determine whether similar changes in deposited amyloid can also occur in other organs, we examined gastric mucosal amyloid before and after LT in FAP patients with ATTRV30M. Methods: We histopathologically and biochemically investigated gastric mucosal amyloid before and after LT in six FAP patients with ATTRV30M.The amounts of amyloid deposits in biopsied gastric mucosa were determined by microscopy, and the proportion of wild-type transthyretin (TTR) in extracted amyloid fibril proteins was assayed by liquid chromatography-ion trap mass spectrometry. Similar examinations were also performed in 21 untreated FAP patients and 13 transplanted patients with ATTRV30M. Results: The amount of deposited amyloid was not markedly different before and after LT in six patients. However, the composition ratios of wild-type TTR in gastric mucosal amyloid increased markedly from 20.0%?±?11.4% before LT to 43.2%?±?13.8% after LT. In addition, the ratio of wild-type TTR in all transplanted patients was significantly higher than that in untransplanted patients (72.7%?±?25.5%, 23.8%?±?14.3%, respectively). Conclusions: Our results showed that the components of amyloid fibril proteins in gastric mucosa of transplanted FAP patients are different from those in untreated patients: a significant portion of preexisting ATTRV30M-derived amyloid seemed to be replaced by wild-type TTR-derived amyloid postoperatively, indicating that continuous turnover of amyloid deposits can occur in all organs in transplanted FAP patients. It was also confirmed that wild-type TTR plays an important role in the pathogenesis of postoperative amyloid deposition in transplanted FAP patients. PMID:23826783

Tsuchiya-Suzuki, Ayako; Yazaki, Masahide; Sekijima, Yoshiki; Kametani, Fuyuki; Ikeda, Shu-Ichi

2013-07-05

45

Steady turnover of amyloid fibril proteins in gastric mucosa after liver transplantation in familial amyloid polyneuropathy.  

UK PubMed Central (United Kingdom)

INTRODUCTION: Our previous study demonstrated marked regression of amyloid deposits in abdominal fat tissues of familial amyloid polyneuropathy (FAP) patients treated with liver transplantation (LT). To determine whether similar changes in deposited amyloid can also occur in other organs, we examined gastric mucosal amyloid before and after LT in FAP patients with ATTRV30M. METHODS: We histopathologically and biochemically investigated gastric mucosal amyloid before and after LT in six FAP patients with ATTRV30M.The amounts of amyloid deposits in biopsied gastric mucosa were determined by microscopy, and the proportion of wild-type transthyretin (TTR) in extracted amyloid fibril proteins was assayed by liquid chromatography-ion trap mass spectrometry. Similar examinations were also performed in 21 untreated FAP patients and 13 transplanted patients with ATTRV30M. RESULTS: The amount of deposited amyloid was not markedly different before and after LT in six patients. However, the composition ratios of wild-type TTR in gastric mucosal amyloid increased markedly from 20.0% ± 11.4% before LT to 43.2% ± 13.8% after LT. In addition, the ratio of wild-type TTR in all transplanted patients was significantly higher than that in untransplanted patients (72.7% ± 25.5%, 23.8% ± 14.3%, respectively). CONCLUSIONS: Our results showed that the components of amyloid fibril proteins in gastric mucosa of transplanted FAP patients are different from those in untreated patients: a significant portion of preexisting ATTRV30M-derived amyloid seemed to be replaced by wild-type TTR-derived amyloid postoperatively, indicating that continuous turnover of amyloid deposits can occur in all organs in transplanted FAP patients. It was also confirmed that wild-type TTR plays an important role in the pathogenesis of postoperative amyloid deposition in transplanted FAP patients.

Tsuchiya-Suzuki A; Yazaki M; Sekijima Y; Kametani F; Ikeda S

2013-09-01

46

Evaluation of colostrum-derived human mammary-associated serum amyloid A3 (M-SAA3) protein and peptide derivatives for the prevention of enteric infection: in vitro and in murine models of intestinal disease.  

Science.gov (United States)

In vitro experiments confirmed that a 10-mer peptide derived from human mammary-associated serum amyloid A3 (M-SAA3) protected intestinal epithelial cells from enteropathogenic Escherichia coli (EPEC) adherence. The entire 42-mer human M-SAA3 protein was even more effective, reducing EPEC binding by 72% relative to untreated cells (PLactobacillus GG, respectively. However, none of the M-SAA3 peptides reduced Salmonella invasion in vitro (P>0.05). Each of the M-SAA3 10-mer peptides and the 42-mer was then administered orally to mice at 500 mug day(-1) for 4 days before deliberate infection with either Citrobacter rodentium (mouse model of EPEC) or Salmonella Typhimurium. None of the peptides protected against Salmonella infection and the 42-mer may even increase infection, as there was a trend towards increased Salmonella counts in the liver and small intestine in 42-mer-treated mice compared with those in sodium acetate-treated control mice. Citrobacter counts were reduced in the caecum of mice administered the 42-mer relative to a scrambled 10-mer (P<0.05), but not compared with the sodium acetate control and no reductions were observed in the faeces or colon. Overall, although promising anti-infective activity was demonstrated in vitro, neither the 42-mer M-SAA3 protein nor a 10-mer peptide derivative prevented enteric infection in the animal models tested. PMID:19220465

Gardiner, Gillian E; O'Flaherty, Sarah; Casey, Pat G; Weber, Annika; McDonald, Thomas L; Cronin, Michael; Hill, Colin; Ross, Reynolds P; Gahan, Cormac G M; Shanahan, Fergus

2009-02-11

47

Transgenic mice overexpressing secreted frizzled-related proteins (sFRP)4 under the control of serum amyloid P promoter exhibit low bone mass but did not result in disturbed phosphate homeostasis.  

Science.gov (United States)

Secreted frizzled-related protein-4 (sFRP4) is a member of secreted modulators of Wnt signaling pathways and has been recognized to play important role in the pathogenesis of oncogenic osteomalacia as a potential phosphatonin. To investigate the role of sFRP4 in bone biology and phosphorus homeostasis in postnatal life, we generated transgenic mice that overexpress sFRP4 under the control of the serum amyloid P promoter (SAP-sFRP4), which drives transgene expression postnatally. Serum phosphorus level and urinary phosphorus excretion were slightly lower and higher, respectively, in SAP-sFRP4 compared to wild-type (WT) littermate, but the difference did not reach statistical significance. However, renal Na(+/-)/Pi co-transporter (Npt) 2a and 1alpha-hydroxylase gene expression were up-regulated in SAP-sFRP4 mice. In addition, the level of serum 1,25-dihydroxyvitamin D(3) was higher in SAP-sFRP4 mice. At 5 weeks of age, bone mineral density (BMD) in SAP-sFRP4 was similar to that in WT. However, with advancing age, SAP-sFRP4 mice gained less BMD so that areal BMD of SAP-sFRP4 mice was significantly lower compared to WT at 15 weeks of age. Histomorphometric analysis of proximal tibia showed that trabecular bone volume (BV/TV) and thickness (Tb.Th) were significantly lower in SAP-sFRP4 mice. There was no evidence of osteomalacia in histological analysis. Our data do not support the role of sFRP4 per se as a phosphatonin but suggest that sFRP4 negatively regulates bone formation without disrupting phosphorus homeostasis. PMID:20472109

Cho, Hwa Young; Choi, Hyung Jin; Sun, Hyun Jin; Yang, Jae-Yeon; An, Jee Hyun; Cho, Sun Wook; Kim, Sang Wan; Kim, Seong Yeon; Kim, Jung Eun; Shin, Chan Soo

2010-05-21

48

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

Energy Technology Data Exchange (ETDEWEB)

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

Saile, R.; Deveaux, M.; Marchandise, X. (Centre Hospitalier Universitaire, 59 - Lille (France). Service Associe de Medecine Nucleaire); Hachulla, E. (Centre Hospitalier Universitaire, 59 - Lille (France). Service de Medecine Interne); Descamps, J. (Centre Regional de Transfusion Sanguine, 59 - Lille (France)); Duquesnoy, B. (Centre Hospitalier Universitaire, 59 - Lille (France). Service de Rhumatologie)

1993-02-01

49

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

International Nuclear Information System (INIS)

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

1993-01-01

50

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Proteolytic processing of the amyloid precursor protein (APP) generates large soluble APP derivatives, ?-amyloid (A?) peptides, and APP intracellular domain. Expression of the extracellular sequences of APP or its Caenorhabditis elegans counterpart has been shown to be sufficient in partially rescui...

Li, Hongmei; Wang, Zilai; Wang, Baiping; Guo, Qinxi; Dolios, Georgia; Tabuchi, Katsuhiko; Hammer, Robert E.; Südhof, Thomas C.

51

Generation of amyloid-? is reduced by the interaction of calreticulin with amyloid precursor protein, presenilin and nicastrin.  

UK PubMed Central (United Kingdom)

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 precursor protein interaction partner that binds to the ?-secretase cleavage site within amyloid precursor protein and showed that this Ca(2+)- and N-glycan-independent interaction is mediated by amino acids 330-344 in the C-terminal C-domain of calreticulin. Co-immunoprecipitation confirmed that calreticulin is not only associated with amyloid precursor protein but also with the ?-secretase complex members presenilin and nicastrin. Calreticulin was detected at the cell surface by surface biotinylation of cells overexpressing amyloid precursor protein and was co-localized by immunostaining with amyloid precursor protein and presenilin at the cell surface of hippocampal neurons. The P-domain of calreticulin located between the N-terminal N-domain and the C-domain interacts with presenilin, the catalytic subunit of the ?-secretase complex. The P- and C-domains also interact with nicastrin, another functionally important subunit of this complex. Transfection of amyloid precursor protein overexpressing cells with full-length calreticulin leads to a decrease in amyloid-?42 levels in culture supernatants, while transfection with the P-domain increases amyloid-?40 levels. Similarly, application of the recombinant P- or C-domains and of a synthetic calreticulin peptide comprising amino acid 330-344 to amyloid precursor protein overexpressing cells result in elevated amyloid-?40 and amyloid-?42 levels, respectively. These findings indicate that the interaction of calreticulin with amyloid precursor protein and the ?-secretase complex regulates the proteolytic processing of amyloid precursor protein by the ?-secretase complex, pointing to calreticulin as a potential target for therapy in Alzheimer's disease.

Stemmer N; Strekalova E; Djogo N; Plöger F; Loers G; Lutz D; Buck F; Michalak M; Schachner M; Kleene R

2013-01-01

52

A prospective study of the sensitivity, specificity and diagnostic performance of soluble intercellular adhesion molecule 1, highly sensitive C-reactive protein, soluble E-selectin and serum amyloid A in the diagnosis of neonatal infection  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Diagnosis of neonatal infection is difficult, because of it's non-specific clinical presentation and the lack of reliable diagnostic tests. The purpose of this study was to examine the potential diagnostic value of serum soluble intercellular adhesion molecule-1 (sICAM-1), soluble E-selectin (sE-selectin), highly sensitive C-reactive protein (hsCRP) and serum amyloid A (SAA) measurements, both individually and in combination in the setting of a neonatal intensive care unit. Methods 219 consecutive serum samples were taken from 149 infants undergoing sepsis work up in a neonatal intensive care unit. Clinical diagnosis was established in a prospective manner, blind to the results of the study measurements. Infants were classified by an experienced paediatrician as infected or not-infected, one week after presentation. Classification was based on clinical presentation, routine laboratory and radiological investigations and response to therapy. The infected group were sub-classified as (a) culture positive infection or (b) culture negative infection. sICAM-1, sE-selectin, hsCRP and SAA levels were determined from stored serum samples after diagnosis was established. Further sub-group analysis of results was undertaken according to early or late onset of infection and preterm or term status. Statistical analysis utilised Mann Whitney U test and ROC curve analysis. Results There were significantly increased serum levels of sICAM-1, hsCRP, E selectin (p Conclusions All four study measurements demonstrated some diagnostic value for neonatal infection however sICAM-1, hsCRP and sE-selectin demonstrated the highest NPV individually. The optimum diagnostic cut off level for hsCRP measurement in this study was much lower than currently used in routine clinical practice. Use of a combination of measurements enhanced diagnostic performance, demonstrating sensitivity of 90.3% and NPV of 91.3%. This study suggests there may be value in use of several of these markers, individually and in combination to assist in excluding neonatal infection. Further work is needed to confirm a specific role in the exclusion of early onset infection.

Edgar J David M; Gabriel Vanessa; Gallimore J Ruth; McMillan Stanley A; Grant Judith

2010-01-01

53

Pyrroloquinoline quinone inhibits the fibrillation of amyloid proteins.  

UK PubMed Central (United Kingdom)

Several neurodegenerative diseases involve the selective damage of neuron cells resulting from the accumulation of amyloid fibril formation. Considering that the formation of amyloid fibrils as well as their precursor oligomers is cytotoxic, the agents that prevent the formation of oligomers and/or fibrils might allow the development of a novel therapeutic approach to neurodegenerative diseases. Here, we show pyrroloquinoline quinone (PQQ) inhibits the amyloid fibril formation of the amyloid proteins, amyloid beta (1-42) and mouse prion protein. The fibril formation of mouse prion protein in the presence of PQQ was dramatically prevented. Similarly, the fibril formation of amyloid beta (1-42) also decreased. With further advanced pharmacological approaches, PQQ may become a leading anti-neurodegenerative compound in the treatment of neurodegenerative diseases.

Kim J; Kobayashi M; Fukuda M; Ogasawara D; Kobayashi N; Han S; Nakamura C; Inada M; Miyaura C; Ikebukuro K; Sode K

2010-01-01

54

Statistical Mechanical Treatments of Protein Amyloid Formation  

CERN Document Server

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

Schreck, John S

2013-01-01

55

Evaluation of colostrum-derived human mammary-associated serum amyloid A3 (M-SAA3) protein and peptide derivatives for the prevention of enteric infection: in vitro and in murine models of intestinal disease.  

UK PubMed Central (United Kingdom)

In vitro experiments confirmed that a 10-mer peptide derived from human mammary-associated serum amyloid A3 (M-SAA3) protected intestinal epithelial cells from enteropathogenic Escherichia coli (EPEC) adherence. The entire 42-mer human M-SAA3 protein was even more effective, reducing EPEC binding by 72% relative to untreated cells (P<0.05), compared with 25% and 57% reductions for the human 10-mer and Lactobacillus GG, respectively. However, none of the M-SAA3 peptides reduced Salmonella invasion in vitro (P>0.05). Each of the M-SAA3 10-mer peptides and the 42-mer was then administered orally to mice at 500 mug day(-1) for 4 days before deliberate infection with either Citrobacter rodentium (mouse model of EPEC) or Salmonella Typhimurium. None of the peptides protected against Salmonella infection and the 42-mer may even increase infection, as there was a trend towards increased Salmonella counts in the liver and small intestine in 42-mer-treated mice compared with those in sodium acetate-treated control mice. Citrobacter counts were reduced in the caecum of mice administered the 42-mer relative to a scrambled 10-mer (P<0.05), but not compared with the sodium acetate control and no reductions were observed in the faeces or colon. Overall, although promising anti-infective activity was demonstrated in vitro, neither the 42-mer M-SAA3 protein nor a 10-mer peptide derivative prevented enteric infection in the animal models tested.

Gardiner GE; O'Flaherty S; Casey PG; Weber A; McDonald TL; Cronin M; Hill C; Ross RP; Gahan CG; Shanahan F

2009-04-01

56

Soluble aggregates of the amyloid-? peptide are trapped by serum albumin to enhance amyloid-? activation of endothelial cells  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Self-assembly of the amyloid-? peptide (A?) has been implicated in the pathogenesis of Alzheimer's disease (AD). As a result, synthetic molecules capable of inhibiting A? self-assembly could serve as therapeutic agents and endogenous molecules that modulate A? self-assembly may influence disease progression. However, increasing evidence implicating a principal pathogenic role for small soluble A? aggregates warns that inhibition at intermediate stages of A? self-assembly may prove detrimental. Here, we explore the inhibition of A?1–40 self-assembly by serum albumin, the most abundant plasma protein, and the influence of this inhibition on A?1–40 activation of endothelial cells for monocyte adhesion. Results It is demonstrated that serum albumin is capable of inhibiting in a dose-dependent manner both the formation of A?1–40 aggregates from monomeric peptide and the ongoing growth of A?1–40 fibrils. Inhibition of fibrillar A?1–40 aggregate growth is observed at substoichiometric concentrations, suggesting that serum albumin recognizes aggregated forms of the peptide to prevent monomer addition. Inhibition of A?1–40 monomer aggregation is observed down to stoichiometric ratios with partial inhibition leading to an increase in the population of small soluble aggregates. Such partial inhibition of A?1–40 aggregation leads to an increase in the ability of resulting aggregates to activate endothelial cells for adhesion of monocytes. In contrast, A?1–40 activation of endothelial cells for monocyte adhesion is reduced when more complete inhibition is observed. Conclusion These results demonstrate that inhibitors of A? self-assembly have the potential to trap small soluble aggregates resulting in an elevation rather than a reduction of cellular responses. These findings provide further support that small soluble aggregates possess high levels of physiological activity and underscore the importance of resolving the effect of A? aggregation inhibitors on aggregate size.

Reyes Barcelo Adriana A; Gonzalez-Velasquez Francisco J; Moss Melissa A

2009-01-01

57

Apple Procyanidins Suppress Amyloid ?-Protein Aggregation  

Science.gov (United States)

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 aggregates in a dose-dependent manner, indicating that PC is a potent suppressor of A? aggregation. Furthermore, PC significantly inhibited A?42 neurotoxicity and stimulated proliferation in PC-12 cells. These results suggested that the PC and AP acted as neuroprotective factors against toxic A? aggregates.

Toda, Toshihiko; Sunagawa, Tadahiro; Kanda, Tomomasa; Tagashira, Motoyuki; Shirasawa, Takuji; Shimizu, Takahiko

2011-01-01

58

Hypoxia Increases Serum Amyloid A3 (SAA3) in Differentiated 3T3-L1 Adipocytes.  

UK PubMed Central (United Kingdom)

Hypoxia has been implicated as a possible cause of adipose tissue inflammation. Furthermore, the acute phase protein serum amyloid A (SAA) has been associated with the modulation of the adipogenic process, and it is well-known that obese individuals have increased levels of SAA. The effect of hypoxia in the expression and production of SAA was examined in murine 3T3-L1 adipocytes. Hypoxia leads to a substantial increase in SAA3 mRNA and protein level, apparently in a time-dependent manner (threefold in 48 h), in fully differentiated 3T3-L1, followed by reestablishment of gene expression to basal levels after 24 h of reoxygenation. Hypoxia-induced SAA may be one of the key molecules to the development of the inflammatory response in adipose tissue.

de Oliveira EM; Sandri S; Knebel FH; Contesini CG; Campa A; Filippin-Monteiro FB

2013-04-01

59

Hypoxia Increases Serum Amyloid A3 (SAA3) in Differentiated 3T3-L1 Adipocytes.  

Science.gov (United States)

Hypoxia has been implicated as a possible cause of adipose tissue inflammation. Furthermore, the acute phase protein serum amyloid A (SAA) has been associated with the modulation of the adipogenic process, and it is well-known that obese individuals have increased levels of SAA. The effect of hypoxia in the expression and production of SAA was examined in murine 3T3-L1 adipocytes. Hypoxia leads to a substantial increase in SAA3 mRNA and protein level, apparently in a time-dependent manner (threefold in 48 h), in fully differentiated 3T3-L1, followed by reestablishment of gene expression to basal levels after 24 h of reoxygenation. Hypoxia-induced SAA may be one of the key molecules to the development of the inflammatory response in adipose tissue. PMID:23605472

de Oliveira, Edson Mendes; Sandri, Silvana; Knebel, Franciele Hinterholz; Contesini, Caroline Garcia Iglesias; Campa, Ana; Filippin-Monteiro, Fabíola Branco

2013-04-20

60

A prospective study of the sensitivity, specificity and diagnostic performance of soluble intercellular adhesion molecule 1, highly sensitive C-reactive protein, soluble E-selectin and serum amyloid A in the diagnosis of neonatal infection.  

UK PubMed Central (United Kingdom)

BACKGROUND: Diagnosis of neonatal infection is difficult, because of it's non-specific clinical presentation and the lack of reliable diagnostic tests. The purpose of this study was to examine the potential diagnostic value of serum soluble intercellular adhesion molecule-1 (sICAM-1), soluble E-selectin (sE-selectin), highly sensitive C-reactive protein (hsCRP) and serum amyloid A (SAA) measurements, both individually and in combination in the setting of a neonatal intensive care unit. METHODS: 219 consecutive serum samples were taken from 149 infants undergoing sepsis work up in a neonatal intensive care unit. Clinical diagnosis was established in a prospective manner, blind to the results of the study measurements. Infants were classified by an experienced paediatrician as infected or not-infected, one week after presentation. Classification was based on clinical presentation, routine laboratory and radiological investigations and response to therapy. The infected group were sub-classified as (a) culture positive infection or (b) culture negative infection. sICAM-1, sE-selectin, hsCRP and SAA levels were determined from stored serum samples after diagnosis was established. Further sub-group analysis of results was undertaken according to early or late onset of infection and preterm or term status. Statistical analysis utilised Mann Whitney U test and ROC curve analysis. RESULTS: There were significantly increased serum levels of sICAM-1, hsCRP, E selectin (p < 0.001) and SAA (p = 0.004) in infected infants compared with non-infected. ROC curve analysis indicated area under the curve values of 0.79 (sICAM-1), 0.73 (hsCRP), 0.72 (sE-selectin) and 0.61 (SAA). ROC curve analysis also defined optimum diagnostic cut-off levels for each measurement. The performance characteristics of sICAM-1, hsCRP and sE-selectin included a high negative predictive value (NPV) for culture positive infection and this was enhanced by combination of all 4 measurements. Clinical subgroup analysis suggested particularly high NPV for early onset symptoms, however further studies are required to elucidate this finding. CONCLUSIONS: All four study measurements demonstrated some diagnostic value for neonatal infection however sICAM-1, hsCRP and sE-selectin demonstrated the highest NPV individually. The optimum diagnostic cut off level for hsCRP measurement in this study was much lower than currently used in routine clinical practice. Use of a combination of measurements enhanced diagnostic performance, demonstrating sensitivity of 90.3% and NPV of 91.3%. This study suggests there may be value in use of several of these markers, individually and in combination to assist in excluding neonatal infection. Further work is needed to confirm a specific role in the exclusion of early onset infection.

Edgar JD; Gabriel V; Gallimore JR; McMillan SA; Grant J

2010-01-01

 
 
 
 
61

ATR-FTIR: a "rejuvenated" tool to investigate amyloid proteins.  

UK PubMed Central (United Kingdom)

Amyloid refers to insoluble protein aggregates that are responsible for amyloid diseases but are also implicated in important physiological functions (functional amyloids). The widespread presence of protein aggregates but also, in most of the cases, their deleterious effects explain worldwide efforts made to understand their formation, structure and biological functions. We emphasized the role of FTIR and especially ATR-FTIR techniques in amyloid protein and/or peptide studies. The multiple advantages provided by ATR-FTIR allow an almost continuous structural view of protein/peptide conversion during the aggregation process. Moreover, it is now well-established that infrared can differentiate oligomers from fibrils simply on their spectral features. ATR-FTIR is certainly the fastest and easiest method to obtain this information. ATR-FTIR occupies a key position in the analysis and comprehension of the complex aggregation mechanism(s) at the oligomer and/or fibril level. These mechanism(s) seem to present strong similarities between different amyloid proteins and might therefore be extremely important to understand for both disease-associated and functional amyloid proteins. This article is part of a Special Issue entitled: FTIR in membrane proteins and peptide studies.

Sarroukh R; Goormaghtigh E; Ruysschaert JM; Raussens V

2013-10-01

62

Ras signal triggers ?-Amyloid Precursor Protein (APP) expression.  

UK PubMed Central (United Kingdom)

It has recently been discovered that the Drosophila ?-amyloid protein precursor like (Appl) gene, the ortholog of the human ?-Amyloid Precursor Protein (APP) gene, is transcriptionally activated by receptor tyrosine kinase activity that involves Ras/MAPK signaling in vivo. This regulation is specifically controlled in photoreceptor neurons of the Drosophila retina. This suggests that some cases of Alzheimer's disease, those which have been associated with high expression of the APP gene, may involve Ras signal transduction.

Mora N; Santa Bárbara P; Ferreira N; Serras F

2013-05-01

63

Use of serum amyloid A and milk amyloid A in the diagnosis of subclinical mastitis in dairy cows.  

UK PubMed Central (United Kingdom)

Mastitis is the most frequent and costly disease in dairy herds, as it negatively affects yield and milk quality. The presence of clinical mastitis is quite easy to asses, whereas the diagnosis of the subclinical form can be more difficult and requires laboratory assays. Somatic cell count (SCC) is widely used as a rapid and low-cost indicator of mastitis, even if is not useful in discriminating between the clinical and subclinical form. As amyloid A has been investigated as a marker of mastitis, the aim of this study was to assess the potential value of measuring amyloid A in serum and milk and the correlation with SCC in the diagnosis of subclinical mastitis. The reliability of two different ELISA kits for the measurement of amyloid A in milk was also tested. During a 1-month trial period, 21 cows were assigned to three experimental groups according to their health status: 6 cows with clinical mastitis (CM), 10 cows with subclinical mastitis (SM) and 5 healthy cows (HE). Amyloid A was measured both in serum (SAA) and in quarter milk samples (mAA) with a serum ELISA kit, and in quarter milk samples (MAA) with a milk ELISA kit. SCC, total microbial count (TMC) and bacterial examination of the milk were also carried out. After a log transformation, the data were submitted to ANOVA and linear regression. TMC was significantly higher in cows with clinical mastitis, while no differences were observed between the other two experimental groups. SCC and MAA levels were significantly different among the three groups. mAA concentrations were similar between cows with subclinical and clinical mastitis, and SAA was not affected by mastitis. A significant correlation between SCC and MAA or mAA was detected, while no correlation was recorded between SAA and mAA. A close relationship between MAA and mAA was noticeable even at low concentrations, suggesting MAA as a potential physiological marker of subclinical mastitis.

Gerardi G; Bernardini D; Azzurra Elia C; Ferrari V; Iob L; Segato S

2009-11-01

64

Serum Amyloid A Circulating Levels and Disease Activity in Patients with Juvenile Idiopathic Arthritis  

Science.gov (United States)

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

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

2012-01-01

65

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Pavel I. Kitov; Eugenia Paszkiewicz; Joanna M. Sadowska; Zhicheng Deng; Marya Ahmed; Ravin Narain; Thomas P. Griener

66

Inhibition of TTR aggregation-induced cell death--a new role for serum amyloid P component.  

UK PubMed Central (United Kingdom)

BACKGROUND: Serum amyloid P component (SAP) is a glycoprotein that is universally found associated with different types of amyloid deposits. It has been suggested that it stabilizes amyloid fibrils and therefore protects them from proteolytic degradation. METHODOLOGY/PRINCIPAL FINDINGS: In this paper, we show that SAP binds not only to mature amyloid fibrils but also to early aggregates of amyloidogenic mutants of the plasma protein transthyretin (TTR). It does not inhibit fibril formation of TTR mutants, which spontaneously form amyloid in vitro at physiological pH. We found that SAP prevents cell death induced by mutant TTR, while several other molecules that are also known to decorate amyloid fibrils do not have such effect. Using a Drosophila model for TTR-associated amyloidosis, we found a new role for SAP as a protective factor in inhibition of TTR-induced toxicity. Overexpression of mutated TTR leads to a neurological phenotype with changes in wing posture. SAP-transgenic flies were crossed with mutated TTR-expressing flies and the results clearly confirmed a protective effect of SAP on TTR-induced phenotype, with an almost complete reduction in abnormal wing posture. Furthermore, we found in vivo that binding of SAP to mutated TTR counteracts the otherwise detrimental effects of aggregation of amyloidogenic TTR on retinal structure. CONCLUSIONS/SIGNIFICANCE: Together, these two approaches firmly establish the protective effect of SAP on TTR-induced cell death and degenerative phenotypes, and suggest a novel role for SAP through which the toxicity of early amyloidogenic aggregates is attenuated.

Andersson K; Pokrzywa M; Dacklin I; Lundgren E

2013-01-01

67

Caspase cleavage of the amyloid precursor protein modulates amyloid beta-protein toxicity.  

UK PubMed Central (United Kingdom)

The amyloid beta-protein precursor (APP) is proteolytically cleaved to generate the amyloid beta-protein (Abeta), the principal constituent of senile plaques found in Alzheimer's disease (AD). In addition, Abeta in its oligomeric and fibrillar forms have been hypothesized to induce neuronal toxicity. We and others have previously shown that APP can be cleaved by caspases at the C-terminus to generate a potentially cytotoxic peptide termed C31. Furthermore, this cleavage event and caspase activation were increased in the brains of AD, but not control, cases. In this study, we show that in cultured cells, Abeta induces caspase cleavage of APP in the C-terminus and that the subsequent generation of C31 contributes to the apoptotic cell death associated with Abeta. Interestingly, both Abeta toxicity and C31 pathway are dependent on the presence of APP. Both APP-dependent Abeta toxicity and C31-induced apoptotic cell death involve apical or initiator caspases-8 and -9. Our results suggest that Abeta-mediated toxicity initiates a cascade of events that includes caspase activation and APP cleavage. These findings link C31 generation and its potential cell death activity to Abeta cytotoxicity, the leading mechanism proposed for neuronal death in AD.

Lu DC; Soriano S; Bredesen DE; Koo EH

2003-11-01

68

Response of salivary haptoglobin and serum amyloid A to social isolation and short road transport stress in pigs.  

UK PubMed Central (United Kingdom)

The possible use of serum amyloid A and haptoglobin (Hp) determination in saliva as stress markers in swine was investigated in this study. Firstly, a model of social isolation was followed. Significantly higher serum amyloid A concentrations were obtained in isolated animals (n=10) compared to grouped animals (n=10; P=0.036), in agreement with cortisol levels (P=0.015), while haptoglobin levels did not significantly change. Secondly, animals were subjected to short road transport. Cortisol and serum amyloid A levels significantly increased following road transport. Serum amyloid A levels were significantly high on arrival at the slaughterhouse and maximal at 30 and 60 min lairage (P<0.0001). Cortisol levels were only significantly elevated on arrival at the slaughterhouse (P<0.0001). These results indicate that salivary serum amyloid A (and not haptoglobin) determination is a potential biomarker for the assessment of complex stress in pigs, and that it has a more prolonged response than cortisol.

Soler L; Gutiérrez A; Escribano D; Fuentes M; Cerón JJ

2013-08-01

69

Transcranial laser therapy attenuates amyloid-? peptide neuropathology in amyloid-? protein precursor transgenic mice.  

UK PubMed Central (United Kingdom)

Transcranial laser therapy (TLT) was tested for efficacy in a mouse model of Alzheimer's disease (AD) using a near-infrared energy laser system. TLT is thought to stimulate ATP production, increase mitochondrial activity, and help maintain neuronal function. Studies were performed to determine the effect of TLT in an amyloid-? protein precursor (A?PP) transgenic mouse model. TLT was administered 3 times/week at various doses, starting at 3 months of age, and was compared to a control group (no laser treatment). Treatment was continued for a total of six months. Animals were examined for amyloid load, inflammatory markers, brain amyloid-? (A?) levels, plasma A? levels, cerebrospinal fluid A? levels, soluble A?PP (sA?PP) levels, and behavioral changes. The numbers of A? plaques were significantly reduced in the brain with administration of TLT in a dose-dependent fashion. Administration of TLT was associated with a dose-dependent reduction in amyloid load. All TLT doses mitigated the behavioral effects seen with advanced amyloid deposition and reduce the expression of inflammatory markers in the A?PP transgenic mice. All TLT doses produced an increase in sA?PP? and a decrease in CTF? levels consistent with inhibition of the ?-secretase activity. In addition, TLT showed an increase in ATP levels, mitochondrial function, and c-fos suggesting an overall improvement in neurological function. These studies suggest that TLT is a potential candidate for treatment of AD.

De Taboada L; Yu J; El-Amouri S; Gattoni-Celli S; Richieri S; McCarthy T; Streeter J; Kindy MS

2011-01-01

70

Transcranial laser therapy attenuates amyloid-? peptide neuropathology in amyloid-? protein precursor transgenic mice.  

Science.gov (United States)

Transcranial laser therapy (TLT) was tested for efficacy in a mouse model of Alzheimer's disease (AD) using a near-infrared energy laser system. TLT is thought to stimulate ATP production, increase mitochondrial activity, and help maintain neuronal function. Studies were performed to determine the effect of TLT in an amyloid-? protein precursor (A?PP) transgenic mouse model. TLT was administered 3 times/week at various doses, starting at 3 months of age, and was compared to a control group (no laser treatment). Treatment was continued for a total of six months. Animals were examined for amyloid load, inflammatory markers, brain amyloid-? (A?) levels, plasma A? levels, cerebrospinal fluid A? levels, soluble A?PP (sA?PP) levels, and behavioral changes. The numbers of A? plaques were significantly reduced in the brain with administration of TLT in a dose-dependent fashion. Administration of TLT was associated with a dose-dependent reduction in amyloid load. All TLT doses mitigated the behavioral effects seen with advanced amyloid deposition and reduce the expression of inflammatory markers in the A?PP transgenic mice. All TLT doses produced an increase in sA?PP? and a decrease in CTF? levels consistent with inhibition of the ?-secretase activity. In addition, TLT showed an increase in ATP levels, mitochondrial function, and c-fos suggesting an overall improvement in neurological function. These studies suggest that TLT is a potential candidate for treatment of AD. PMID:21116053

De Taboada, Luis; Yu, Jin; El-Amouri, Salim; Gattoni-Celli, Sebastiano; Richieri, Steve; McCarthy, Thomas; Streeter, Jackson; Kindy, Mark S

2011-01-01

71

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 hypoth...

Viana, JS; Neves, S; Vieira, H; Bento, C; Perdigoto, R; Furtado, AL

72

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"&uiLanguage=en">F.H.D. González; F.H. Ruipérez"&uiLanguage=en">F.H. Ruipérez; J.M. Sánchez"&uiLanguage=en">J.M. Sánchez; J.C. Souza"&uiLanguage=en">J.C. Souza; S. Martínez-Subiela"&uiLanguage=en">S. Martínez-Subiela; J.J. Cerón"&uiLanguage=en">J.J. Cerón

2010-01-01

73

Serum amyloid P is a sialylated glycoprotein inhibitor of influenza A viruses.  

UK PubMed Central (United Kingdom)

Members of the pentraxin family, including PTX3 and serum amyloid P component (SAP), have been reported to play a role in innate host defence against a range of microbial pathogens, yet little is known regarding their antiviral activities. In this study, we demonstrate that human SAP binds to human influenza A virus (IAV) strains and mediates a range of antiviral activities, including inhibition of IAV-induced hemagglutination (HA), neutralization of virus infectivity and inhibition of the enzymatic activity of the viral neuraminidase (NA). Characterization of the anti-IAV activity of SAP after periodate or bacterial sialidase treatment demonstrated that ?(2,6)-linked sialic acid residues on the glycosidic moiety of SAP are critical for recognition by the HA of susceptible IAV strains. Other proteins of the innate immune system, namely human surfactant protein A and porcine surfactant protein D, have been reported to express sialylated glycans which facilitate inhibition of particular IAV strains, yet the specific viral determinants for recognition of these inhibitors have not been defined. Herein, we have selected virus mutants in the presence of human SAP and identified specific residues in the receptor-binding pocket of the viral HA which are critical for recognition and therefore susceptibility to the antiviral activities of SAP. Given the widespread expression of ?(2,6)-linked sialic acid in the human respiratory tract, we propose that SAP may act as an effective receptor mimic to limit IAV infection of airway epithelial cells.

Job ER; Bottazzi B; Gilbertson B; Edenborough KM; Brown LE; Mantovani A; Brooks AG; Reading PC

2013-01-01

74

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

UK PubMed Central (United Kingdom)

BACKGROUND: Peritoneal fluid (PF) analysis is a valuable diagnostic tool in equine medicine. Markers such as serum amyloid A (SAA) and haptoglobin (Hp) could facilitate the diagnosis of inflammatory abdominal conditions. OBJECTIVES: The objectives were to (1) establish reference intervals (RI) for SAA and Hp in serum and PF in healthy horses, (2) compare SAA and Hp concentrations between healthy horses and horses with colic, and (3) to assess the correlation between serum and PF concentrations. METHODS: Serum amyloid A and Hp concentrations were determined by automated assays in prospectively enrolled healthy reference horses and horses with colic. RIs were calculated, group concentrations were compared by Student's t-test, and Pearson's correlation for serum and PF concentrations were determined. RESULTS: In healthy horses (n = 62) the measurements for SAA were below the detection limit (0.5 mg/L) in 94% of serum samples and 98% of PF samples. Horses with colic (n = 61) had statistically significantly increased SAA concentrations in serum (P < .0001) and PF (P = .0013). While PF Hp concentrations were increased in horses with colic the serum concentrations of Hp were decreased (P < .0001). There was a strong correlation between paired serum and PF SAA concentrations (n = 94, R = .72, P < .0001), whereas the correlation between paired serum and PF Hp was weak (n = 94, R = .22, P = .0382). Finally, horses with colic tended to have serum SAA and PF Hp concentrations above the RIs. CONCLUSIONS: With the apparent difference between healthy horses and horses with colic and the presently established RIs, serum SAA and PF Hp concentrations represent potential valuable diagnostic markers for inflammatory abdominal conditions in that species.

Pihl TH; Andersen PH; Kjelgaard-Hansen M; Mørck NB; Jacobsen S

2013-06-01

75

Serum amyloid A inhibits dendritic cell apoptosis to induce glucocorticoid resistance in CD4(+) T cells.  

Science.gov (United States)

Mediators produced by the airway epithelium control the activation, recruitment, and survival of pulmonary dendritic cells (DC) that present antigen to CD4(+) T cells during the genesis and exacerbation of allergic asthma. The epithelial-derived acute phase protein, serum amyloid A (SAA), induces DC maturation and TH17 polarization. TH17 responses are associated with severe forms of allergic asthma that are poorly controlled by corticosteroids. We sought to determine whether SAA would enhance the survival of DC during serum starvation and could then contribute to the development of a glucocorticoid-resistant phenotype in CD4(+) T cells. Bone marrow-derived dendritic cells (BMDC) that were serum starved in the presence of SAA were protected from activation of caspase-3 and released less lactate dehydrogenase. In comparison with untreated serum-starved BMDC, treatment with SAA downregulated mRNA expression of the pro-apoptotic molecule Bim, increased production of the pro-survival heat shock protein 70 (HSP70), and induced secretion of pro-inflammatory cytokines. SAA-treated BMDC that were serum starved for 48?h remained capable of presenting antigen and induced OTII CD4(+) T cells to secrete IL-17A, IL-17F, IL-21, IL-22, and IFN? in the presence of ovalbumin. IL-17A, IL-17F, IL-21, and IFN? production occurred even when the CD4(+) T cells were treated with dexamethasone (Dex), whereas glucocorticoid treatment abolished cytokine secretion by T cells cocultured with untreated serum-starved BMDC. Measurement of Dex-responsive gene expression demonstrated CD4(+) T cells as the target of glucocorticoid hyperresponsiveness manifest as a consequence of BMDC stimulation by SAA. Finally, allergic airway disease induced by SAA and antigen inhalation was unresponsive to Dex treatment. Our results indicate that apo-SAA affects DC to both prolong their viability and increase their inflammatory potential under apoptosis-inducing conditions. These findings reveal mechanisms through which SAA enhances the CD4(+) T-cell-stimulating capacity of antigen-presenting cells that may actively participate in the pathogenicity of glucocorticoid-resistant lung disease. PMID:24008730

Ather, J L; Fortner, K A; Budd, R C; Anathy, V; Poynter, M E

2013-09-05

76

Serum amyloid A inhibits dendritic cell apoptosis to induce glucocorticoid resistance in CD4+ T cells  

Science.gov (United States)

Mediators produced by the airway epithelium control the activation, recruitment, and survival of pulmonary dendritic cells (DC) that present antigen to CD4+ T cells during the genesis and exacerbation of allergic asthma. The epithelial-derived acute phase protein, serum amyloid A (SAA), induces DC maturation and TH17 polarization. TH17 responses are associated with severe forms of allergic asthma that are poorly controlled by corticosteroids. We sought to determine whether SAA would enhance the survival of DC during serum starvation and could then contribute to the development of a glucocorticoid-resistant phenotype in CD4+ T cells. Bone marrow-derived dendritic cells (BMDC) that were serum starved in the presence of SAA were protected from activation of caspase-3 and released less lactate dehydrogenase. In comparison with untreated serum-starved BMDC, treatment with SAA downregulated mRNA expression of the pro-apoptotic molecule Bim, increased production of the pro-survival heat shock protein 70 (HSP70), and induced secretion of pro-inflammatory cytokines. SAA-treated BMDC that were serum starved for 48?h remained capable of presenting antigen and induced OTII CD4+ T cells to secrete IL-17A, IL-17F, IL-21, IL-22, and IFN? in the presence of ovalbumin. IL-17A, IL-17F, IL-21, and IFN? production occurred even when the CD4+ T cells were treated with dexamethasone (Dex), whereas glucocorticoid treatment abolished cytokine secretion by T cells cocultured with untreated serum-starved BMDC. Measurement of Dex-responsive gene expression demonstrated CD4+ T cells as the target of glucocorticoid hyperresponsiveness manifest as a consequence of BMDC stimulation by SAA. Finally, allergic airway disease induced by SAA and antigen inhalation was unresponsive to Dex treatment. Our results indicate that apo-SAA affects DC to both prolong their viability and increase their inflammatory potential under apoptosis-inducing conditions. These findings reveal mechanisms through which SAA enhances the CD4+ T-cell-stimulating capacity of antigen-presenting cells that may actively participate in the pathogenicity of glucocorticoid-resistant lung disease.

Ather, J L; Fortner, K A; Budd, R C; Anathy, V; Poynter, M E

2013-01-01

77

Caspr interaction with Amyloid Precursor Protein reduces amyloid-? generation in vitro.  

UK PubMed Central (United Kingdom)

Contactin associated protein (Caspr), an adhesion molecule, plays roles in formation of paranodal junctions in myelinated axons, neurite outgrowth, synaptic plasticity in nervous system. Here we have shown a novel function of Caspr in pathogenesis of Alzheimer's disease (AD). Caspr distributes around amyloid plaques in APP/PS1 mice. Levels of Caspr increase in the cerebral cortex of 7-month-old APP/PS1 mice comparing to wild-type littermates. Caspr decreased protein levels of APP in both HEK-293 cells stably transfected with Indiana mutant APP (V717F; HEK-APP) and CHO cells which express endogenous APP, while it did not alter mRNA levels of APP. Furthermore, Caspr co-localizes and interacts with APP. Amyloid-? (A?) 40 and A?42 generation were also reduced in HEK-APP cells by Caspr overexpression.

Fan LF; Xu DE; Wang WH; Yan K; Wu H; Yao XQ; Xu RX; Liu CF; Ma QH

2013-08-01

78

[Study on serum protein mass spectrometric characteristics of acute leukemia].  

UK PubMed Central (United Kingdom)

OBJECTIVE: To study the serum protein differential expression in acute leukemia patients and healthy control by differential protein mass spectrometry. METHODS: Serum proteins of 51 acute leukemia (AL) patients and 10 healthy donors were extracted from their peripheral blood. After removing high abundance protein, serum low abundance proteins were separated by two dimensional gel electrophoresis, the differences of serum proteins in AL patients and healthy human were identified. The protein spots with differential expression were cut out and then undergone bleaching, gel digestion and peptide extraction. The peptide mass fingerprint analysis was performed by using MALDI TOF/TOF MS. The protein database MSDB Masort retrieval program was used to evaluate the results. RESULTS: Using Student's t test,19 statistically significant abnormal expression proteins in the serum of AL patients were found compared with the healthy controls (P < 0.05). The expression of ?1-trypsin inhibitor (P < 0.01), prealbumin (P < 0.01), trypsin inhibitor (P < 0.01), apolipoprotein E (P < 0.01) and apolipoprotein A-? (P < 0.01) decreased, while retinol binding protein (P < 0.05), globin HP2 (P < 0.05), serum lectin (P < 0.05), H factor homologue protein (P < 0.05) and serum amyloid A1 (P < 0.01) increased. Further stratified analysis found that high serum lectin expression in AL patient resulted in poor outcomes. CONCLUSION: There are a variety of serum proteins with differential expression in peripheral blood of AL patients. The differential expression of serum lectin is related to the therapeutic effect. The differential expression of these proteins can be used as a new diagnosis marker or prognostic indicator for acute leukemia.

Zheng RJ; Ma XD

2013-05-01

79

Non-amyloid and amyloid prion protein deposits in prion-infected mice differ in blockage of interstitial brain fluid.  

UK PubMed Central (United Kingdom)

AIMS: Prion diseases are characterized by brain deposits of misfolded aggregated protease-resistant prion protein (PrP), termed PrPres. In humans and animals, PrPres is found as either disorganized non-amyloid aggregates or organized amyloid fibrils. Both PrPres forms are found in extracellular spaces of the brain. Thus, both might block drainage of brain interstitial fluid (ISF). The present experiments studied whether ISF blockage occurred during amyloid and/or non-amyloid prion diseases. METHODS: Various-sized fluorescein-labelled ISF tracers were stereotactically inoculated into the striatum of adult mice. At times from 5 min to 77 h, uninfected and scrapie-infected mice were compared. C57BL/10 mice expressing wild-type anchored PrP, which develop non-amyloid PrPres similar to humans with sporadic Creutzfeldt-Jakob disease, were compared with Tg44+/+ mice (transgenic mice secreting anchorless PrP) expressing anchorless PrP, which develop amyloid PrPres similar to certain human familial prion diseases. RESULTS: In C57BL/10 mice, extensive non-amyloid PrPres aggregate deposition was not associated with abnormal clearance kinetics of tracers. In contrast, scrapie-infected Tg44+/+ mice showed blockage of tracer clearance and colocalization of tracer with perivascular PrPres amyloid. CONCLUSIONS: As tracer localization and clearance was normal in infected C57BL/10 mice, ISF blockage was not an important pathogenic mechanism in this model. Therefore, ISF blockage is unlikely to be a problem in non-amyloid human prion diseases such as sporadic Creutzfeldt-Jakob disease. In contrast, partial ISF blockage appeared to be a possible pathogenic mechanism in Tg44+/+ mice. Thus this mechanism might also influence human amyloid prion diseases where expression of anchorless or mutated PrP results in perivascular amyloid PrPres deposition and cerebral amyloid angiopathy.

Rangel A; Race B; Striebel J; Chesebro B

2013-04-01

80

Deformation behavior and mechanical properties of amyloid protein nanowires.  

Science.gov (United States)

Amyloid fibrils are most often associated with their pathological role in diseases like Alzheimer's disease and Parkinson's disease, but they are now increasingly being considered for uses in functional engineering materials. They are among the stiffest protein fibers known but they are also rather brittle, and it is unclear how this combination of properties affects the behavior of amyloid structures at larger length scales, such as in films, wires or plaques. Using a coarse-grained model for amyloid fibrils, we study the mechanical response of amyloid nanowires and examine fundamental mechanical properties, including mechanisms of deformation and failure under tensile loading. We also explore the effect of varying the breaking strain and adhesion strength of the constituent amyloid fibrils on the properties of the larger structure. We find that deformation in the nanowires is controlled by a combination of fibril sliding and fibril failure and that there exists a transition from brittle to ductile behavior by either increasing the fibril failure strain or decreasing the strength of adhesion between fibrils. Furthermore, our results reveal that the mechanical properties of the nanowires are quite sensitive to changes in the properties of the individual fibrils, and the larger scale structures are found to be more mechanically robust than the constituent fibrils, for all cases considered. More broadly, this work demonstrates the promise of utilizing self-assembled biological building blocks in the development of hierarchical nanomaterials. PMID:23290516

Solar, Max; Buehler, Markus J

2012-11-28

 
 
 
 
81

Deformation behavior and mechanical properties of amyloid protein nanowires.  

UK PubMed Central (United Kingdom)

Amyloid fibrils are most often associated with their pathological role in diseases like Alzheimer's disease and Parkinson's disease, but they are now increasingly being considered for uses in functional engineering materials. They are among the stiffest protein fibers known but they are also rather brittle, and it is unclear how this combination of properties affects the behavior of amyloid structures at larger length scales, such as in films, wires or plaques. Using a coarse-grained model for amyloid fibrils, we study the mechanical response of amyloid nanowires and examine fundamental mechanical properties, including mechanisms of deformation and failure under tensile loading. We also explore the effect of varying the breaking strain and adhesion strength of the constituent amyloid fibrils on the properties of the larger structure. We find that deformation in the nanowires is controlled by a combination of fibril sliding and fibril failure and that there exists a transition from brittle to ductile behavior by either increasing the fibril failure strain or decreasing the strength of adhesion between fibrils. Furthermore, our results reveal that the mechanical properties of the nanowires are quite sensitive to changes in the properties of the individual fibrils, and the larger scale structures are found to be more mechanically robust than the constituent fibrils, for all cases considered. More broadly, this work demonstrates the promise of utilizing self-assembled biological building blocks in the development of hierarchical nanomaterials.

Solar M; Buehler MJ

2013-03-01

82

Anti-serum amyloid component P antibodies in patients with systemic lupus erythematosus correlate with disease activity  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Objective: To determine the presence of raised titres of anti-serum amyloid P component (SAP) antibodies in patients with systemic lupus erythematosus (SLE) and to evaluate their correlation with clinical disease by the SLEDAI and clinical manifestations.

Zandman-Goddard, G; Blank, M; Langevitz, P; Slutsky, L; Pras, M; Levy, Y; Shovman, O; Witte, T; Doria, A; Rovensky, J; Shoenfeld, Y

83

Metastability of native proteins and the phenomenon of amyloid formation.  

UK PubMed Central (United Kingdom)

An experimental determination of the thermodynamic stabilities of a series of amyloid fibrils reveals that this structural form is likely to be the most stable one that protein molecules can adopt even under physiological conditions. This result challenges the conventional assumption that functional forms of proteins correspond to the global minima in their free energy surfaces and suggests that living systems are conformationally as well as chemically metastable.

Baldwin AJ; Knowles TP; Tartaglia GG; Fitzpatrick AW; Devlin GL; Shammas SL; Waudby CA; Mossuto MF; Meehan S; Gras SL; Christodoulou J; Anthony-Cahill SJ; Barker PD; Vendruscolo M; Dobson CM

2011-09-01

84

Metastability of native proteins and the phenomenon of amyloid formation.  

Science.gov (United States)

An experimental determination of the thermodynamic stabilities of a series of amyloid fibrils reveals that this structural form is likely to be the most stable one that protein molecules can adopt even under physiological conditions. This result challenges the conventional assumption that functional forms of proteins correspond to the global minima in their free energy surfaces and suggests that living systems are conformationally as well as chemically metastable. PMID:21650202

Baldwin, Andrew J; Knowles, Tuomas P J; Tartaglia, Gian Gaetano; Fitzpatrick, Anthony W; Devlin, Glyn L; Shammas, Sarah Lucy; Waudby, Christopher A; Mossuto, Maria F; Meehan, Sarah; Gras, Sally L; Christodoulou, John; Anthony-Cahill, Spencer J; Barker, Paul D; Vendruscolo, Michele; Dobson, Christopher M

2011-08-19

85

Serum amyloid A (SAA) concentration after training sessions in Arabian race and endurance horses.  

UK PubMed Central (United Kingdom)

BACKGROUND: Serum amyloid A (SAA) is the major acute phase protein in horses. Its concentration increases in various pathologies but also in response to prolonged, strenuous effort. The purpose of this study was to establish whether routine race and endurance training produces changes in the SAA level in Arabian horses. Additionally, the differences between SAA response in experienced endurance horses and endurance horses that were beginning their career were investigated. RESULTS: There were no changes in SAA concentrations after race training and endurance training in experienced horses. In horses that were beginning their endurance training, exercise produced an increase in SAA level as compared with rest level. CONCLUSION: In Arabians, the SAA concentration seems to be a good indicator of endurance training but is useless in race training. The routine training of experienced horses, which were prepared for long distance rides, did not promote any changes in the SAA level. In contrast, a significant increase in the SAA concentration was observed in horses that were beginning their endurance training and were only prepared for moderate distance rides and underwent the same effort. Further research is needed to elucidate whether this difference reflects too heavy training or adaptation to an increasing workload. Additionally, the adaptation to long distance rides in Arabians may include a reduced acute phase response.

Cywinska A; Witkowski L; Szarska E; Schollenberger A; Winnicka A

2013-01-01

86

Serum amyloid A is found on ApoB-containing lipoproteins in obese humans with diabetes.  

UK PubMed Central (United Kingdom)

OBJECTIVE: In murine models of obesity/diabetes, there is an increase in plasma serum amyloid A (SAA) levels along with redistribution of SAA from high-density lipoprotein (HDL) to apolipoprotein B (apoB)-containing lipoprotein particles, namely, low-density lipoprotein and very low-density lipoprotein. The goal of this study was to determine if obesity is associated with similar SAA lipoprotein redistribution in humans. DESIGN AND METHODS: Three groups of obese individuals were recruited from a weight loss clinic: healthy obese (n = 14), metabolic syndrome (MetS) obese (n = 8), and obese with type 2 diabetes (n = 6). Plasma was separated into lipoprotein fractions by fast protein liquid chromatography, and SAA was measured in lipid fractions using enzyme-linked immunosorbent assay and Western blotting. RESULTS: Only the obese diabetic group had SAA detectable in apoB-containing lipoproteins, and SAA reverted back to HDL with active weight loss. CONCLUSIONS: In human subjects, SAA is found in apoB-containing lipoprotein particles only in obese subjects with type 2 diabetes, but not in healthy obese or obese subjects with MetS.

Jahangiri A; Wilson PG; Hou T; Brown A; King VL; Tannock LR

2013-05-01

87

Homocysteine induces serum amyloid A3 in osteoblasts via unlocking RGD-motifs in collagen.  

Science.gov (United States)

Hyperhomocysteinemia is a risk factor for osteoporotic fractures. Homocysteine (Hcys) inhibits collagen cross-linking and consequently decreases bone extracellular matrix (ECM) quality. Serum amyloid A (A-SAA), an acute-phase protein family, plays an important role in chronic and inflammatory diseases and up-regulates MMP13, which plays an important role in bone development and remodeling. Here, we investigate the effect of Hcys on expression of SAA3, a member of the A-SAA gene family, in osteoblasts characterizing underlying mechanisms and possible consequences on bone metabolism. MC3T3-E1 osteoblast-like cells were cultured up to 21 d with Hcys (low millimolar range) or reseeded onto ECM resulting from untreated or Hcys-treated MC3T3-E1 cells. Fourier-transformed infrared spectroscopy and a discriminative antibody were used to characterize the resulting ECM. Gene expression and signaling pathways were analyzed by gene chip, quantitative RT-PCR, and immunoblotting. Transcriptional regulation of Saa3 was studied by promoter transfection assays, chromatin immunoprecipitation, and immunofluorescence microscopy. Hcys treatment resulted in reduced collagen cross-linking, uncovering of RGD-motifs, and activation of the PTK2-PXN-CTNNB1 pathway followed by RELA activation. These signaling events led to increased SAA3 expression followed by the production of MMP13 and several chemokines, including Ccl5, Ccl2, Cxcl10, and Il6. Our data suggest Saa3 as link between hyperhomocysteinemia and development of osteoporosis. PMID:23085993

Thaler, Roman; Zwerina, Jochen; Rumpler, Monika; Spitzer, Silvia; Gamsjaeger, Sonja; Paschalis, Eleftherios P; Klaushofer, Klaus; Varga, Franz

2012-10-19

88

Serum amyloid A-positive hepatocellular neoplasms in the resected livers from 3 patients with alcoholic cirrhosis.  

Science.gov (United States)

Twelve hepatocellular nodules were characterized in the resected livers from 3 patients (2 men and a woman) with alcoholic cirrhosis. Imaging techniques suggested that the nodules were hypervascular and may be hepatocellular carcinoma. Five nodules (4-31 mm in diameter) were serum amyloid A-positive hepatocellular neoplasm, which shares features with inflammatory hepatocellular adenoma. The remaining 7 nodules (5-8 mm) were focal nodular hyperplasia-like nodules showing focal or no immunostaining for serum amyloid A. The serum amyloid A-positive hepatocellular neoplasms showed increased cellular density, inflammatory infiltrate, sinusoidal dilatation, and ductular reaction to various degrees. These histologic features tended to be less extensive in focal nodular hyperplasia-like nodules. Three of 4 serum amyloid A-positive hepatocellular neoplasms showed slight hypointensity in the hepatobiliary phase on the magnetic resonance (MR) imaging with gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) enhancement. In contrast, 3 focal nodular hyperplasia-like nodules showed iso-intensity in the hepatobiliary phase. This study further confirms characteristics of serum amyloid A-positive hepatocellular neoplasm arising in alcoholic cirrhosis that share features with inflammatory hepatocellular adenomas. Serum amyloid A-positive hepatocellular neoplasms sometimes co-exist with focal nodular hyperplasia-like nodules and may show different findings on Gd-EOB-enhanced MR imaging. PMID:23690168

Sasaki, Motoko; Kondo, Fukuo; Sawai, Yoshiyuki; Imai, Yasuharu; Kadowaki, Susumu; Sano, Keiji; Fukusato, Toshio; Matsui, Osamu; Nakanuma, Yasuni

2013-05-21

89

Calcitonin Gene-Related Peptide Upregulates Serum Amyloid A Synthesis through Activation of Interleukin-6.  

UK PubMed Central (United Kingdom)

We found that calcitonin gene-related peptide (CGRP) enhanced the expression of levels of serum amyloid A (SAA) and interleukin-6 (IL-6) in HepG2. In addition, CGRP-induced SAA1/2 mRNA expression was blocked by an anti-IL-6 neutralizing antibody in HepG2. These results suggest that CGRP promotes SAA synthesis through activation of IL-6 in human hepatocytes.

Matsui S; Yamane T; Kobayashi-Hattori K; Oishi Y

2013-10-01

90

Serum amyloid A concentration in healthy periparturient mares and mares with ascending placentitis.  

UK PubMed Central (United Kingdom)

REASONS FOR PERFORMING STUDY: Placentitis is a prevalent cause of abortion, premature delivery and neonatal death in mares. Early diagnosis is paramount for the survival of the fetus and delivery of a live foal. OBJECTIVES: To determine: 1) Serum amyloid A (SAA) profile in healthy mares during late gestation; 2) if placentitis affects SAA concentrations and 3) the effects of therapy on SAA concentrations and pregnancy outcome in mares with placentitis. METHODS: In Experiment I, 15 healthy pregnant mares were evaluated from 280 days of gestation to 60 h post partum. In Experiment II, pregnant mares were inoculated intra-cervically with Streptococcus zooepidemicus (Day 280-295) and assigned to control (n = 5) and treatment (n = 9) groups. Treatment was initiated at the onset of clinical signs. Serum amyloid A concentrations were determined prior to inoculation and then weekly until abortion or delivery. RESULTS: Serum amyloid A remained at low concentrations (95% confidence interval [CI]: 3.2-8.1?mg/l) during late gestation followed by a significant increase within 36 h post partum; SAA returned to basal concentrations by 60 h post partum. In Experiment II, SAA significantly increased within 96 ± 56 h of inoculation in control mares followed by abortion. Therapy was effective (P<0.05) in preventing the rise in SAA in 66% (6/9) of mares and only one out of 3 mares with increased SAA aborted. Overall, the incidence of abortion was higher in mares with increased SAA concentrations (75%; 6/8) compared with mares in which SAA remained at baseline concentrations (0/6). CONCLUSIONS: Mares with placentitis had significant increased SAA within 96 h post inoculation and concentrations remained increased until abortion in untreated mares. Successful treatment either prevented the rise of SAA concentration or decreased its concentration to baseline concentrations, followed by delivery of a live foal. POTENTIAL RELEVANCE: Serum amyloid A may be used as a prognostic indicator in cases of ascending placentitis in the mare.

Coutinho da Silva MA; Canisso IF; MacPherson ML; Johnson AE; Divers TJ

2013-09-01

91

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

92

Scintigraphic imaging and turnover studies with iodine-131 labelled serum amyloid P component in systemic amyloidosis  

International Nuclear Information System (INIS)

Radiolabelled serum amyloid P component (SAP) is a specific tracer for amyloid. Iodine-123 has ideal physical characteristics for scintigraphy but is expensive and not widely available. Here we report serial imaging and turnover studies in which we labelled SAP with iodine-131, a cheap alternative isotope which would be expected to yield poorer images but permit more prolonged turnover measurements. Imaging and plasma clearance and whole body retention (WBR) of tracer were studied for up to 7 days in ten patients with proven systemic AL amyloidosis and two patients in whom the diagnosis was suspected, after i.v. administration of about 37 MBq of 131I-SAP. Normal blood pool images were obtained in the latter two subjects and amyloidosis was subsequently refuted histologically. WBR at 48 h was 65% of the injected dose (i.d.). Among the other ten patients, amyloid deposits were identified in the spleen in eight cases, liver in five and kidneys in four; other sites that gave positive results included bone, joints and soft tissues, and the myocardium in one case. Up to 95% of the tracer localised into amyloid within 6-h, and the values for WBR became progressively more discriminating during the study period, exceeding the normal reference value (131I-SAP produced diagnostic scans in every patient in this series and, coupled with the detailed turnover information, is adequate for monitoring disease progress. (orig.)

1998-01-01

93

Deposition of amyloid fibrils promotes cell-surface accumulation of amyloid beta precursor protein.  

UK PubMed Central (United Kingdom)

Amyloid beta protein (Abeta) deposition and neuronal degeneration are characteristic pathological features of Alzheimer's disease (AD). In vitro, Abeta fibrils (fAbeta) induce neuronal degeneration reminiscent to AD, but the mechanism of neurotoxicity is unknown. Here we show that amyloid fibrils increase the level of cell-surface full-length amyloid beta precursor protein (h-AbetaPP) and secreted AbetaPP (s-AbetaPP). Pulse-chase analysis indicated that fAbeta selectively inhibited the turnover of cell-surface AbetaPP, without altering its intracellular levels. FAbeta-induced AbetaPP accumulation was not abrogated by cycloheximide, suggesting that increased protein synthesis is not critically required. Abeta fibrils sequester s-AbetaPP from the culture medium and promote its accumulation at the cell surface, indicating that binding of Abeta fibrils mediates AbetaPP accumulation. A time course analysis of Abeta treatment showed that AbetaPP level is elevated before significant cell death can be detected, while other toxic insults do not augment AbetaPP level, suggesting that AbetaPP may be specifically involved in early stages of Abeta-induced neurodegeneration. Finally, Abeta fibrils promote clustering of h-AbetaPP in abnormal focal adhesion-like (FA-like) structures that mediate neuronal dystrophy, increasing its association with the cytoskeleton. These results indicate that the interaction of Abeta fibrils with AbetaPP is an early event in the mechanism of Abeta-induced neurodegeneration that may play a significant role in AD pathogenesis.

Heredia L; Lin R; Vigo FS; Kedikian G; Busciglio J; Lorenzo A

2004-08-01

94

Amyloid Precursor Protein Processing in Alzheimer’s Disease  

Directory of Open Access Journals (Sweden)

Full Text Available lzheimer’s disease (AD) is a progressive neurodegenerative disorder and a leading cause of dementia. The AD is characterized by presence of intraneuronal tangles and extracellular plaques in the brain. The plaques are composed of dense and mostly insoluble deposits of amyloid beta peptide (A?), formed by sequential cleavage of the Amyloid Precursor Protein (APP), by two pathways amyloidogenic and non-amyloidogenic. Tangles are composed of paired helical fragments, which aggregate to form, microtubular protein tau. Although A? plaques are established to be the cause of the disease, there exist genetic factors and other pathological identifications in addition to these which are an integral part of the disease. This article gives an overview into the mechanism of APP action, genetic factors and other pathological identifications contributing to Alzheimer’s disease formation.

Adwait BHADBHADE; Davis Weizhong CHENG

2012-01-01

95

Human amyloid beta protein gene locus: HaeIII RFLP  

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

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

1988-07-25

96

Differential affinity of serum amyloid A1 isotypes for high-density lipoprotein.  

UK PubMed Central (United Kingdom)

Serum amyloid A (SAA), a precursor of reactive amyloid deposits, is a multigene product. SAA1, predominant both as an amyloid precursor and in plasma, consists of three allelic variants (SAA1.1, SAA1.3, and SAA1.5). Several investigations have shown that the SAA1.3 allele is associated with susceptibility to AA-amyloidosis in Japanese, and the SAA1.5 allele is related with higher serum concentrations of SAA. However, these results have not been interpreted functionally. This study assessed the affinity of SAA isotypes for high-density lipoprotein (HDL), to which SAA binds in plasma. Using a surface plasmon resonance-based apparatus (BIAcore), the affinity between immobilized recombinant human SAAs and HDL was determined. The SAA concentration was measured in fractions after ultracentrifugation (d = 1.23) of sera from patients with rheumatoid arthritis, whose SAA1 genotypes were determined. In the BIAcore analysis, as the dissociation reaction under the conditions used was too rapid to fit the typical kinetic model, the steady-state affinity model was used. The affinity (kd) of SAA1.1, SAA1.3, and SAA1.5 for HDL was 1.4 x 10(-5), 1.8 x 10(-5), and 3.7 x 10(-6), respectively. rSAA1.5 showed significantly (p < 0.05) stronger affinity than the other two. The fraction of lipid-free SAA in serum was significantly (p < 0.001) lower in the patients with larger numbers of the 1.5 allele at the SAA1 locus. These results suggest that the relatively high affinity of SAA1.5 may cause the high serum concentration and may be related to the low susceptibility to amyloidosis.

Yamada T; Sato J; Okuda Y

2009-12-01

97

Protein Polymers and Amyloids : Focus on ?1-Antitrypsin  

DEFF Research Database (Denmark)

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

RisØr, Michael Wulff

2013-01-01

98

Changes in amyloid-? and Tau in the cerebrospinal fluid of transgenic mice overexpressing amyloid precursor protein.  

UK PubMed Central (United Kingdom)

Altered concentrations of amyloid-? (A?) peptide and Tau protein in the cerebrospinal fluid (CSF) are thought to be predictive markers for Alzheimer's disease (AD). Transgenic mice overexpressing human amyloid precursor protein (APP) have been used to model A? pathology, but concomitant changes in A? and Tau in CSF have been less well studied. We measured A? and Tau in the brains and CSF of two well-characterized transgenic mouse models of AD: one expressing human APP carrying the Swedish mutation (APP23) and the other expressing mutant human APP and mutant human presenilin-1 (APPPS1). Both mouse models exhibit A? deposition in the brain, but with different onset and progression trajectories. We found an age-related 50 to 80% decrease in A?42 peptide in mouse CSF and a smaller decrease in A?40, both inversely correlated with the brain A? load. Surprisingly, the same mice showed a threefold increase in total endogenous murine Tau in CSF at the stages when A? pathology became prominent. The results mirror the temporal sequence and magnitude of A? and Tau changes in the CSF of patients with sporadic and dominantly inherited AD. This observation indicates that APP transgenic mice may be useful as a translational tool for predicting changes in A? and Tau markers in the CSF of AD patients. These findings also suggest that APP transgenic mouse models may be useful in the search for new disease markers for AD.

Maia LF; Kaeser SA; Reichwald J; Hruscha M; Martus P; Staufenbiel M; Jucker M

2013-07-01

99

Neuronal origin of a cerebral amyloid: neurofibrillary tangles of Alzheimer's disease contain the same protein as the amyloid of plaque cores and blood vessels.  

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The protein component of Alzheimer's disease amyloid [neurofibrillary tangles (NFT), amyloid plaque core and congophilic angiopathy] is an aggregated polypeptide with a subunit mass of 4 kd (the A4 monomer). Based on the degree of N-terminal heterogeneity, the amyloid is first deposited in the neuro...

Masters, C L; Multhaup, G; Simms, G; Pottgiesser, J; Martins, R N; Beyreuther, K

100

Response of salivary haptoglobin and serum amyloid A to social isolation and short road transport stress in pigs.  

Science.gov (United States)

The possible use of serum amyloid A and haptoglobin (Hp) determination in saliva as stress markers in swine was investigated in this study. Firstly, a model of social isolation was followed. Significantly higher serum amyloid A concentrations were obtained in isolated animals (n=10) compared to grouped animals (n=10; P=0.036), in agreement with cortisol levels (P=0.015), while haptoglobin levels did not significantly change. Secondly, animals were subjected to short road transport. Cortisol and serum amyloid A levels significantly increased following road transport. Serum amyloid A levels were significantly high on arrival at the slaughterhouse and maximal at 30 and 60 min lairage (P<0.0001). Cortisol levels were only significantly elevated on arrival at the slaughterhouse (P<0.0001). These results indicate that salivary serum amyloid A (and not haptoglobin) determination is a potential biomarker for the assessment of complex stress in pigs, and that it has a more prolonged response than cortisol. PMID:23566790

Soler, L; Gutiérrez, A; Escribano, D; Fuentes, M; Cerón, J J

2013-04-06

 
 
 
 
101

Serum amyloid A, in vivo splenic cholesterol export and its potential implications in hemolytic disorders.  

Science.gov (United States)

A model to examine the in vivo relationship of acute phase serum amyloid A (SAA) to spleen cholesterol mobilisation was devised. Reticuloendothelial cells in vivo were loaded with a known quantity of cholesterol (1.5 mg) by infusing fragmented red blood cell membranes, which consist of approximately 50% cholesterol by dry weight. Following infusion, 7% of the infused cholesterol was in the spleen and significantly increased (by 35%) spleen cholesterol concentration above the baseline. An acute inflammatory reaction was induced by the subcutaneous injection of AgNO(3) which also raised spleen cholesterol values, but not significantly. Both treatments were also administered together and the increase in spleen cholesterol concentration after 1 h was equivalent to the sum of the individual treatments. In all the treatment groups, the spleen cholesterol concentration and the plasma SAA values were then followed over a period of 24 h. In all treatment groups the spleen cholesterol values fell to baseline values primarily between 18 and 24 h which coincided with significantly raised levels of plasma SAA. In the case of the dual treatment, between 4 and 18 h, SAA increased from 92.1 +/- 12.3 to 478 +/- 58.3 microg/ml, respectively and depletion of spleen cholesterol occurred gradually reaching baseline values after 24 h. The significant flux of cholesterol though the spleen raises the distinct possibility that the spleen is much more involved in cholesterol metabolism than previously appreciated. Furthermore, the speed with which plasma SAA increases following the infusion of fragmented red blood cell membranes and the role that SAA plays in cholesterol mobilisation raise issues that may be relevant to alterations in plasma acute phase protein and lipid parameters in patients undergoing transfusions or suffering from hemolytic disorders. PMID:19065296

Li, Chunyan; Kisilevsky, Robert

2008-12-01

102

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

Science.gov (United States)

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

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

2013-07-11

103

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

UK PubMed Central (United Kingdom)

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

Oh J; Yoo G; Chang YW; Kim HJ; Jose J; Kim E; Pyun JC; Yoo KH

2013-12-01

104

Theoretical models of the ion channel structure of amyloid beta-protein.  

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Theoretical methods are used to develop models for the ion channel structure of the membrane-bound amyloid beta-protein. This follows recent observations that the beta-protein forms cation-selective channels in lipid bilayers in vitro. Amyloid beta-protein is the main component of the extracellular ...

Durell, S R; Guy, H R; Arispe, N; Rojas, E; Pollard, H B

105

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; Kazuya Takeda; Hiroyuki Kaji; Masato Taoka; Tomotaka Shinoda

2001-01-01

106

BACE2, a ?-secretase homolog, cleaves at the ? site and within the amyloid-? region of the amyloid-? precursor protein  

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Production of amyloid-? protein (A?) is initiated by a ?-secretase that cleaves the A? precursor protein (APP) at the N terminus of A? (the ? site). A recently identified aspartyl protease, BACE, cleaves the ? site and at residue 11 within the A? region of APP. Here we show that BACE2, a BACE homolo...

Farzan, Michael; Schnitzler, Christine E.; Vasilieva, Natalya; Leung, Doris; Choe, Hyeryun

107

A heparin-binding protein from neuroblastoma cells: immunological comparison to beta-amyloid precursor protein.  

UK PubMed Central (United Kingdom)

1. beta-Amyloid precursor protein cross-reactive polypeptides were detected in the membrane extracts of a mouse neuroblastoma cell line, NB41A3. Four immunoreactive polypeptide bands were observed on western blots of a cell membrane extract. Their molecular weights as estimated by polyacrylamide gel electrophoresis ranged from 89.1 to 41 kDa. 2. After heparin affinity chromatography, two of these polypeptides strongly cross-reacted with an antibody that recognizes Alzheimer beta-amyloid precursor protein. 3. From the heparin binding fraction, these protein were further separated by reverse-phase high-performance liquid chromatography. A cross-reactive protein was isolated.

Zhao XH; Schoenheit C; Duffy LK

1991-01-01

108

A heparin-binding protein from neuroblastoma cells: immunological comparison to beta-amyloid precursor protein.  

Science.gov (United States)

1. beta-Amyloid precursor protein cross-reactive polypeptides were detected in the membrane extracts of a mouse neuroblastoma cell line, NB41A3. Four immunoreactive polypeptide bands were observed on western blots of a cell membrane extract. Their molecular weights as estimated by polyacrylamide gel electrophoresis ranged from 89.1 to 41 kDa. 2. After heparin affinity chromatography, two of these polypeptides strongly cross-reacted with an antibody that recognizes Alzheimer beta-amyloid precursor protein. 3. From the heparin binding fraction, these protein were further separated by reverse-phase high-performance liquid chromatography. A cross-reactive protein was isolated. PMID:1685979

Zhao, X H; Schoenheit, C; Duffy, L K

1991-01-01

109

Redundancy and divergence in the amyloid precursor protein family.  

UK PubMed Central (United Kingdom)

Gene duplication provides genetic material required for functional diversification. An interesting example is the amyloid precursor protein (APP) protein family. The APP gene family has experienced both expansion and contraction during evolution. The three mammalian members have been studied quite extensively in combined knock out models. The underlying assumption is that APP, amyloid precursor like protein 1 and 2 (APLP1, APLP2) are functionally redundant. This assumption is primarily supported by the similarities in biochemical processing of APP and APLPs and on the fact that the different APP genes appear to genetically interact at the level of the phenotype in combined knockout mice. However, unique features in each member of the APP family possibly contribute to specification of their function. In the current review, we discuss the evolution and the biology of the APP protein family with special attention to the distinct properties of each homologue. We propose that the functions of APP, APLP1 and APLP2 have diverged after duplication to contribute distinctly to different neuronal events. Our analysis reveals that APLP2 is significantly diverged from APP and APLP1.

Shariati SA; De Strooper B

2013-06-01

110

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

UK PubMed Central (United Kingdom)

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. multifiliis and emphasize the importance of the fish skin as an active organ in response to an ectoparasite infection.

Gonzalez SF; Buchmann K; Nielsen ME

2007-01-01

111

Serum amyloid A as an indicator of health status in falcons.  

UK PubMed Central (United Kingdom)

Serum amyloid A (SAA) is used as an indicator of health status in many species. To investigate the possible use of SAA as a health indicator in falcons, SAA levels were measured in 259 falcons of varying species and health status. A significant increase (P < .001) in SAA concentrations was observed in falcons affected by inflammatory disease compared with healthy birds and birds with noninflammatory disease. Serum amyloid A concentrations ranged from 0.1 to 6.8 mg/L (mean [SD], 3.4 +/- 1.4 mg/L) in the healthy group, from 0.8 to 8.5 mg/L (mean [SD], 4.0 +/- 3.1 mg/L) in the group with noninflammatory disease, and from 2.3 to 137.5 mg/L (mean [SD], 47.7 +/- 29.7 mg/L) in the group with inflammatory disease. In birds with chronic pododermatitis or fungal pneumonia/airsacculitis, SAA levels remained significantly increased throughout the study period. These results indicate that SAA concentrations can be used in avian medicine to assess the health status of falcons and as a prognostic indicator of certain pathologic disease processes.

Caliendo V; McKinney P; Bailey T; Kinne J; Wernery U

2013-06-01

112

Serum amyloid A as a prognostic marker in cats with various diseases.  

UK PubMed Central (United Kingdom)

Serum amyloid A (SAA) is reported not only as a marker for the presence of inflammation but also as a prognostic indicator in human beings. In cats, however, there is no report on the association between SAA concentration and prognosis. The objective of the current study was to evaluate SAA concentration as a prognostic marker in diseased cats. A total of 175 cats with neoplastic diseases, inflammatory diseases, and other diseases were retrospectively recruited, and the medical records of these cats, including follow-up data on mortality, were reviewed. Cats were divided into 2 groups according to SAA concentration, and differences in survival between each group were assessed. Median survival time of cats in the elevated SAA (>0.82 mg/l) group was significantly shorter than that in the nonelevated SAA (?0.82 mg/l) group (P < 0.001). Furthermore, by multivariate analysis, SAA concentration was shown as a significant and independent prognostic marker in cats with various diseases (P = 0.015). Serum amyloid A concentration in diseased cats is a useful predictive indicator of prognosis regardless of diagnosis.

Tamamoto T; Ohno K; Takahashi M; Nakashima K; Fujino Y; Tsujimoto H

2013-05-01

113

Piezoelectric microcantilever serum protein detector  

Science.gov (United States)

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

Capobianco, Joseph A.

114

A second cytotoxic proteolytic peptide derived from amyloid beta-protein precursor.  

UK PubMed Central (United Kingdom)

The amyloid beta-protein precursor gives rise to the amyloid beta-protein, the principal constituent of senile plaques and a cytotoxic fragment involved in the pathogenesis of Alzheimer disease. Here we show that amyloid beta-protein precursor was proteolytically cleaved by caspases in the C terminus to generate a second unrelated peptide, called C31. The resultant C31 peptide was a potent inducer of apoptosis. Both caspase-cleaved amyloid beta-protein precursor and activated caspase-9 were present in brains of Alzheimer disease patients but not in control brains. These findings indicate the possibility that caspase cleavage of amyloid beta-protein precursor with the generation of C31 may be involved in the neuronal death associated with Alzheimer disease.

Lu DC; Rabizadeh S; Chandra S; Shayya RF; Ellerby LM; Ye X; Salvesen GS; Koo EH; Bredesen DE

2000-04-01

115

Scintigraphic imaging and turnover studies with iodine-131 labelled serum amyloid P component in systemic amyloidosis  

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Radiolabelled serum amyloid P component (SAP) is a specific tracer for amyloid. Iodine-123 has ideal physical characteristics for scintigraphy but is expensive and not widely available. Here we report serial imaging and turnover studies in which we labelled SAP with iodine-131, a cheap alternative isotope which would be expected to yield poorer images but permit more prolonged turnover measurements. Imaging and plasma clearance and whole body retention (WBR) of tracer were studied for up to 7 days in ten patients with proven systemic AL amyloidosis and two patients in whom the diagnosis was suspected, after i.v. administration of about 37 MBq of {sup 131}I-SAP. Normal blood pool images were obtained in the latter two subjects and amyloidosis was subsequently refuted histologically. WBR at 48 h was <60% and 6-h plasma activity was >65% of the injected dose (i.d.). Among the other ten patients, amyloid deposits were identified in the spleen in eight cases, liver in five and kidneys in four; other sites that gave positive results included bone, joints and soft tissues, and the myocardium in one case. Up to 95% of the tracer localised into amyloid within 6-h, and the values for WBR became progressively more discriminating during the study period, exceeding the normal reference value (<25%) in all cases by day 7. The optimal imaging time was found to be between 24 and 48 h. The duration of the study enabled us to measure the tracer elimination half-life which was increased in all cases by up to tenfold. Follow-up studies performed after 2-24 months in four patients who were treated with iododoxorubicin showed regression of amyloid in one patient and a small increase in one case; in the other two patients the imaging and turnover studies were identical to baseline. Despite its unfavourable imaging characteristics, {sup 131}I-SAP produced diagnostic scans in every patient in this series and, coupled with the detailed turnover information, is adequate for monitoring disease progress. (orig.) With 5 figs., 2 tabs., 19 refs.

Hawkins, P.N.; Pepys, M.B. [Immunological Medicine Unit, Department of Medicine, Royal Postgraduate Medical School, London (United Kingdom); Aprile, C. [Nuclear Medicine Service, Scientific Institute Fondazione Maugeri, Pavia (Italy); Capri, G.; Vigano, L.; Munzone, E.; Gianni, L. [Division of Medical Oncology, Istituto Nazionale Tumori, Milan (Italy); Merlini, G. [Biotechnology Research Laboratories, University Hospital S. Matteo, Pavia (Italy)

1998-07-01

116

Cellular prion protein modulates ?-amyloid deposition in aged APP/PS1 transgenic mice.  

Science.gov (United States)

Alzheimer's disease and prion diseases are neuropathological disorders that are caused by abnormal processing and aggregation of amyloid and prion proteins. Interactions between amyloid precursor protein (APP) and PrP(c) proteins have been described at the neuron level. Accordingly to this putative interaction, we investigated whether ?-amyloid accumulation may affect prion infectivity and, conversely, whether different amounts of PrP may affect ?-amyloid accumulation. For this purpose, we used the APPswe/PS1dE9 mouse line, a common model of Alzheimer's disease, crossed with mice that either overexpress (Tga20) or that lack prion protein (knock-out) to generate mice that express varying amounts of prion protein and deposit ?-amyloid. On these mouse lines, we investigated the influence of each protein on the evolution of both diseases. Our results indicated that although the presence of APP/PS1 and ?-amyloid accumulation had no effect on prion infectivity, the accumulation of ?-amyloid deposits was dependent on PrP(c), whereby increasing levels of prion protein were accompanied by a significant increase in ?-amyloid aggregation associated with aging. PMID:23831375

Ordóñez-Gutiérrez, Lara; Torres, Juan María; Gavín, Rosalina; Antón, Marta; Arroba-Espinosa, Ana Isabel; Espinosa, Juan-Carlos; Vergara, Cristina; Del Río, José A; Wandosell, Francisco

2013-07-04

117

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 B; SØrensen, Jens Christian

2013-01-01

118

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

UK PubMed Central (United Kingdom)

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 MB; Sørensen JC; Jacobsen S; Kjelgaard-Hansen M

2013-01-01

119

The amyloid precursor protein and postnatal neurogenesis/neuroregeneration  

International Nuclear Information System (INIS)

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

2006-03-03

120

The role of ?-secretase activating protein (GSAP) and imatinib in the regulation of ?-secretase activity and amyloid-? generation.  

UK PubMed Central (United Kingdom)

?-Secretase is a large enzyme complex comprising presenilin, nicastrin, presenilin enhancer 2, and anterior pharynx-defective 1 that mediates the intramembrane proteolysis of a large number of proteins including amyloid precursor protein and Notch. Recently, a novel ?-secretase activating protein (GSAP) was identified that interacts with ?-secretase and the C-terminal fragment of amyloid precursor protein to selectively increase amyloid-? production. In this study we have further characterized the role of endogenous and exogenous GSAP in the regulation of ?-secretase activity and amyloid-? production in vitro. Knockdown of GSAP expression in N2a cells decreased amyloid-? levels. In contrast, overexpression of GSAP in HEK cells expressing amyloid precursor protein or in N2a cells had no overt effect on amyloid-? generation. Likewise, purified recombinant GSAP had no effect on amyloid-? generation in two distinct in vitro ?-secretase assays. In subsequent cellular studies with imatinib, a kinase inhibitor that reportedly prevents the interaction of GSAP with the C-terminal fragment of amyloid precursor protein, a concentration-dependent decrease in amyloid-? levels was observed. However, no interaction between GSAP and the C-terminal fragment of amyloid precursor protein was evident in co-immunoprecipitation studies. In addition, subchronic administration of imatinib to rats had no effect on brain amyloid-? levels. In summary, these findings suggest the roles of GSAP and imatinib in the regulation of ?-secretase activity and amyloid-? generation are uncertain.

Hussain I; Fabrègue J; Anderes L; Ousson S; Borlat F; Eligert V; Berger S; Dimitrov M; Alattia JR; Fraering PC; Beher D

2013-01-01

 
 
 
 
121

The role of ?-secretase activating protein (GSAP) and imatinib in the regulation of ?-secretase activity and amyloid-? generation.  

Science.gov (United States)

?-Secretase is a large enzyme complex comprising presenilin, nicastrin, presenilin enhancer 2, and anterior pharynx-defective 1 that mediates the intramembrane proteolysis of a large number of proteins including amyloid precursor protein and Notch. Recently, a novel ?-secretase activating protein (GSAP) was identified that interacts with ?-secretase and the C-terminal fragment of amyloid precursor protein to selectively increase amyloid-? production. In this study we have further characterized the role of endogenous and exogenous GSAP in the regulation of ?-secretase activity and amyloid-? production in vitro. Knockdown of GSAP expression in N2a cells decreased amyloid-? levels. In contrast, overexpression of GSAP in HEK cells expressing amyloid precursor protein or in N2a cells had no overt effect on amyloid-? generation. Likewise, purified recombinant GSAP had no effect on amyloid-? generation in two distinct in vitro ?-secretase assays. In subsequent cellular studies with imatinib, a kinase inhibitor that reportedly prevents the interaction of GSAP with the C-terminal fragment of amyloid precursor protein, a concentration-dependent decrease in amyloid-? levels was observed. However, no interaction between GSAP and the C-terminal fragment of amyloid precursor protein was evident in co-immunoprecipitation studies. In addition, subchronic administration of imatinib to rats had no effect on brain amyloid-? levels. In summary, these findings suggest the roles of GSAP and imatinib in the regulation of ?-secretase activity and amyloid-? generation are uncertain. PMID:23209290

Hussain, Ishrut; Fabrègue, Julien; Anderes, Laurence; Ousson, Solenne; Borlat, Frédéric; Eligert, Valérie; Berger, Sébastien; Dimitrov, Mitko; Alattia, Jean-René; Fraering, Patrick C; Beher, Dirk

2012-12-03

122

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

123

Altered concentrations of amyloid precursor protein metabolites in the cerebrospinal fluid of patients with bipolar disorder.  

UK PubMed Central (United Kingdom)

Bipolar disorder is a psychiatric disorder characterized by recurrent episodes of mania/hypomania and depression. Progressive cognitive dysfunction such as impairments in executive function and verbal memory is common in euthymic bipolar patients. The cerebrospinal fluid has previously been used to study neurodegenerative processes in Alzheimer's disease, from which changes in three core biomarkers have emerged as indicative of degeneration: amyloid ?, total tau, and hyperphosphorylated tau. Here, neurodegeneration in bipolar disorder was investigated by assessing the association between bipolar disorder and cerebrospinal fluid biomarkers for neurodegenerative processes. Cerebrospinal fluid was obtained from 139 bipolar disorder patients and 71 healthy controls. Concentrations of total and phosphorylated tau, amyloid ?1-42, amyloid ?38/?40/?42, and the soluble forms of amyloid precursor protein were measured in patients vs controls. The concentrations of the soluble forms of amyloid precursor protein were significantly lower in bipolar patients compared with controls. The amyloid ?42/amyloid ?38 and the amyloid ?42/amyloid ?40 ratios were higher in bipolar patients than controls. There were no discernible differences in the concentrations of total/phosphorylated tau, amyloid ?1-42, or amyloid ?38/?40/?42. The concentrations of the biomarkers within the bipolar patient group were further associated with different ongoing medical treatments and diagnostic subgroups. The findings suggest that the amyloid precursor protein metabolism is altered in bipolar disorder. The results may have implications for the understanding of the pathophysiology of bipolar disorder and for the development of treatment strategies. Importantly, there were no signs of an Alzheimer-like neurodegenerative process among bipolar patients.

Jakobsson J; Zetterberg H; Blennow K; Johan Ekman C; Johansson AG; Landén M

2013-03-01

124

Nascent HDL formation by hepatocytes is reduced by the concerted action of serum amyloid A and endothelial lipase  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Inflammation is associated with significant decreases in plasma HDL-cholesterol (HDL-C) and apoA-I levels. Endothelial lipase (EL) is known to be an important determinant of HDL-C in mice and in humans and is upregulated during inflammation. In this study, we investigated whether serum amyloid A (SA...

Wroblewski, Joanne M.; Jahangiri, Anisa; Ji, Ailing; de Beer, Frederick C.; van der Westhuyzen, Deneys R.; Webb, Nancy R.

125

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

126

Intracellular amyloid precursor protein sorting and amyloid-? secretion are regulated by Src-mediated phosphorylation of Mint2.  

UK PubMed Central (United Kingdom)

Mint adaptor proteins bind to the membrane-bound amyloid precursor protein (APP) and affect the production of pathogenic amyloid-? (A?) peptides related to Alzheimer's disease (AD). Previous studies have shown that loss of each of the three Mint proteins delays the age-dependent production of amyloid plaques in transgenic mouse models of AD. However, the cellular and molecular mechanisms underlying Mints effect on amyloid production are unclear. Because A? generation involves the internalization of membrane-bound APP via endosomes and Mints bind directly to the endocytic motif of APP, we proposed that Mints are involved in APP intracellular trafficking, which in turn, affects A? generation. Here, we show that APP endocytosis was attenuated in Mint knock-out neurons, revealing a role for Mints in APP trafficking. We also show that the endocytic APP sorting processes are regulated by Src-mediated phosphorylation of Mint2 and that internalized APP is differentially sorted between autophagic and recycling trafficking pathways. A Mint2 phosphomimetic mutant favored endocytosis of APP along the autophagic sorting pathway leading to increased intracellular A? accumulation. Conversely, the Mint2 phospho-resistant mutant increased APP localization to the recycling pathway and back to the cell surface thereby enhancing A?42 secretion. These results demonstrate that Src-mediated phosphorylation of Mint2 regulates the APP endocytic sorting pathway, providing a mechanism for regulating A? secretion.

Chaufty J; Sullivan SE; Ho A

2012-07-01

127

Progressive accumulation of amyloid-beta oligomers in Alzheimer's disease and in amyloid precursor protein transgenic mice is accompanied by selective alterations in synaptic scaffold proteins.  

Science.gov (United States)

The cognitive impairment in patients with Alzheimer's disease is closely associated with synaptic loss in the neocortex and limbic system. Although the neurotoxic effects of aggregated amyloid-beta oligomers in Alzheimer's disease have been studied extensively in experimental models, less is known about the characteristics of these aggregates across the spectrum of Alzheimer's disease. In this study, postmortem frontal cortex samples from controls and patients with Alzheimer's disease were fractionated and analyzed for levels of oligomers and synaptic proteins. We found that the levels of oligomers correlated with the severity of cognitive impairment (blessed information-memory-concentration score and mini-mental state examination) and with the loss of synaptic markers. Reduced levels of the synaptic vesicle protein, vesicle-associated membrane protein-2, and the postsynaptic protein, postsynaptic density-95, correlated with the levels of oligomers in the various fractions analyzed. The strongest associations were found with amyloid-beta dimers and pentamers. Co-immunoprecipitation and double-labeling experiments supported the possibility that amyloid-beta and postsynaptic density-95 interact at synaptic sites. Similarly, in transgenic mice expressing high levels of neuronal amyloid precursor protein, amyloid-beta co-immunoprecipitated with postsynaptic density-95. This was accompanied by a decrease in the levels of the postsynaptic proteins Shank1 and Shank3 in patients with Alzheimer's disease and in the brains of amyloid precursor protein transgenic mice. In conclusion, this study suggests that the presence of a subpopulation of amyloid-beta oligomers in the brains of patients with Alzheimer's disease might be related to alterations in selected synaptic proteins and cognitive impairment. PMID:20573181

Pham, Emiley; Crews, Leslie; Ubhi, Kiren; Hansen, Lawrence; Adame, Anthony; Cartier, Anna; Salmon, David; Galasko, Douglas; Michael, Sarah; Savas, Jeffrey N; Yates, John R; Glabe, Charles; Masliah, Eliezer

2010-06-22

128

Progressive accumulation of amyloid-beta oligomers in Alzheimer's disease and in amyloid precursor protein transgenic mice is accompanied by selective alterations in synaptic scaffold proteins.  

UK PubMed Central (United Kingdom)

The cognitive impairment in patients with Alzheimer's disease is closely associated with synaptic loss in the neocortex and limbic system. Although the neurotoxic effects of aggregated amyloid-beta oligomers in Alzheimer's disease have been studied extensively in experimental models, less is known about the characteristics of these aggregates across the spectrum of Alzheimer's disease. In this study, postmortem frontal cortex samples from controls and patients with Alzheimer's disease were fractionated and analyzed for levels of oligomers and synaptic proteins. We found that the levels of oligomers correlated with the severity of cognitive impairment (blessed information-memory-concentration score and mini-mental state examination) and with the loss of synaptic markers. Reduced levels of the synaptic vesicle protein, vesicle-associated membrane protein-2, and the postsynaptic protein, postsynaptic density-95, correlated with the levels of oligomers in the various fractions analyzed. The strongest associations were found with amyloid-beta dimers and pentamers. Co-immunoprecipitation and double-labeling experiments supported the possibility that amyloid-beta and postsynaptic density-95 interact at synaptic sites. Similarly, in transgenic mice expressing high levels of neuronal amyloid precursor protein, amyloid-beta co-immunoprecipitated with postsynaptic density-95. This was accompanied by a decrease in the levels of the postsynaptic proteins Shank1 and Shank3 in patients with Alzheimer's disease and in the brains of amyloid precursor protein transgenic mice. In conclusion, this study suggests that the presence of a subpopulation of amyloid-beta oligomers in the brains of patients with Alzheimer's disease might be related to alterations in selected synaptic proteins and cognitive impairment.

Pham E; Crews L; Ubhi K; Hansen L; Adame A; Cartier A; Salmon D; Galasko D; Michael S; Savas JN; Yates JR; Glabe C; Masliah E

2010-07-01

129

Crystal Structure of an Active Form of BACE1, an Enzyme Responsible for Amyloid ? Protein Production?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

BACE1 (?-secretase) is a transmembrane aspartic protease that cleaves the ?-amyloid precursor protein and generates the amyloid ? peptide (A?). BACE1 cycles between the cell surface and the endosomal system many times and becomes activated interconvertibly during its cellular trafficking, leading to...

Shimizu, Hideaki; Tosaki, Asako; Kaneko, Kumi; Hisano, Tamao; Sakurai, Takashi; Nukina, Nobuyuki

130

[The role of serum amyloid A in the early diagnosis of acute coronary syndrome].  

UK PubMed Central (United Kingdom)

The aim of this study was to evaluate diagnostic usefulness of serum amyloid A (SAA) in diagnosis of acute myocardial infarction (AMI) in group of patients with stenocardia. The study was carried out in group of 62 patients admitted to Emergency Unit of 5-th Military Hospital in Krakow. The study group consisted of 24 (38.7%) patients with unstable angina pectoris and 38 (61.3%) with acute myocardial infarction. It was found that SAA concentration significantly increases in patients with AMI: 136.0 +/- 220.6 mg/L versus 7.38 +/- 8.8 mg/L in unstable angina pectoris (p < or = 0.009). Studies of mutual relations between SAA levels and cardiac markers have shown a remarkably positive correlation between SAA and troponin I (r = 0.39; p < or = 0.01) and negative correlation between SAA concentrations and platelet count decrease (r = -0.55; p < or = 0.01).

Cabala M; Gajdosz R

2005-01-01

131

[The role of serum amyloid A in the early diagnosis of acute coronary syndrome].  

Science.gov (United States)

The aim of this study was to evaluate diagnostic usefulness of serum amyloid A (SAA) in diagnosis of acute myocardial infarction (AMI) in group of patients with stenocardia. The study was carried out in group of 62 patients admitted to Emergency Unit of 5-th Military Hospital in Krakow. The study group consisted of 24 (38.7%) patients with unstable angina pectoris and 38 (61.3%) with acute myocardial infarction. It was found that SAA concentration significantly increases in patients with AMI: 136.0 +/- 220.6 mg/L versus 7.38 +/- 8.8 mg/L in unstable angina pectoris (p < or = 0.009). Studies of mutual relations between SAA levels and cardiac markers have shown a remarkably positive correlation between SAA and troponin I (r = 0.39; p < or = 0.01) and negative correlation between SAA concentrations and platelet count decrease (r = -0.55; p < or = 0.01). PMID:16053213

Cabala, Marcin; Gajdosz, Ryszard

2005-01-01

132

Serum amyloid A as a marker and mediator of acute coronary syndromes.  

UK PubMed Central (United Kingdom)

Inflammation promotes acute coronary syndromes and ensuing clinical complications. An emerging downstream marker of inflammation is serum amyloid A (SAA). Elevated plasma SAA levels predict increased cardiovascular risk and portend worse prognosis in patients with acute coronary artery disease (CAD). The pathophysiological role of SAA remains enigmatic. SAA plays a role in host defense, but it might also be atherogenic. SAA affects cholesterol transport, contributes to endothelial dysfunction, promotes thrombosis, evokes recruitment of inflammatory cells, activates neutrophils and suppresses neutrophil apoptosis, key events underlying acute coronary syndromes. These results provide a potential link between SAA and CAD and suggest that reducing SAA levels and/or opposing the actions of SAA may have beneficial effects in patients with acute CAD.

Filep JG; El Kebir D

2008-09-01

133

Amyloid beta-protein dimers rapidly form stable synaptotoxic protofibrils.  

UK PubMed Central (United Kingdom)

Nonfibrillar, water-soluble low-molecular weight assemblies of the amyloid ?-protein (A?) are believed to play an important role in Alzheimer's disease (AD). Aqueous extracts of human brain contain A? assemblies that migrate on SDS-polyacrylamide gels and elute from size exclusion as dimers (?8 kDa) and can block long-term potentiation and impair memory consolidation in the rat. Such species are detected specifically and sensitively in extracts of Alzheimer brain suggesting that SDS-stable dimers may be the basic building blocks of AD-associated synaptotoxic assemblies. Consequently, understanding the structure and properties of A? dimers is of great interest. In the absence of sufficient brain-derived dimer to facilitate biophysical analysis, we generated synthetic dimers designed to mimic the natural species. For this, A?(1-40) containing cysteine in place of serine 26 was used to produce disulphide cross-linked dimer, (A?S26C)2. Such dimers had no detectable secondary structure, produced an analytical ultracentrifugation profile consistent for an ?8.6 kDa protein, and had no effect on hippocampal long-term potentiation (LTP). However, (A?S26C)2 aggregated more rapidly than either A?S26C or wild-type monomers and formed parastable ?-sheet rich, thioflavin T-positive, protofibril-like assemblies. Whereas wild-type A? aggregated to form typical amyloid fibrils, the protofibril-like structures formed by (A?S26C)2 persisted for prolonged periods and potently inhibited LTP in mouse hippocampus. These data support the idea that A? dimers may stabilize the formation of fibril intermediates by a process distinct from that available to A? monomer and that higher molecular weight prefibrillar assemblies are the proximate mediators of A? toxicity.

O'Nuallain B; Freir DB; Nicoll AJ; Risse E; Ferguson N; Herron CE; Collinge J; Walsh DM

2010-10-01

134

Amyloid fibrils from readily available sources: milk casein and lens crystallin proteins.  

UK PubMed Central (United Kingdom)

Amyloid fibrils are a highly ordered and robust aggregated form of protein structure in which the protein components are arranged in long fibrillar arrays comprised of ?-sheet. Because of these properties, along with their biocompatibility, amyloid fibrils have attracted much research attention as bionanomaterials, for example as template structures (in some cases following modification) that can be used as biosensors, encapsulators, and biomimetic materials. To use amyloid fibrils for such a range of applications will require them to be obtained relatively easily in large quantities. In this chapter, we describe methods for isolating crystallin and casein proteins from readily available sources that contain abundant protein, i.e., the eye lens and milk, respectively, and the subsequent conversion of these proteins into amyloid fibrils.

Ecroyd H; Garvey M; Thorn DC; Gerrard JA; Carver JA

2013-01-01

135

Adipocyte-derived serum amyloid A3 and hyaluronan play a role in monocyte recruitment and adhesion.  

Science.gov (United States)

Obesity is characterized by adipocyte hypertrophy and macrophage accumulation in adipose tissue. Monocyte chemoattractant protein-1 (MCP-1) plays a role in macrophage recruitment into adipose tissue. However, other adipocyte-derived factors, e.g., hyaluronan and serum amyloid A (SAA), can facilitate monocyte adhesion and chemotaxis, respectively. The objective was to test the potential involvement of these factors in macrophage recruitment. Differentiated 3T3-L1 adipocytes made hypertrophic by growth in high glucose conditions were used to study SAA and hyaluronan regulation in vitro. Two mouse models of obesity were used to study their expression in vivo. Nuclear factor-kappaB was upregulated and peroxisome proliferator-activated receptor (PPAR)gamma was downregulated in hypertrophic 3T3-L1 cells, with increased expression of SAA3 and increased hyaluronan production. Rosiglitazone, a PPARgamma agonist, reversed these changes. Hypertrophic adipocytes demonstrated overexpression of SAA3 and hyaluronan synthase 2 in vitro and in vivo in diet-induced and genetic obesity. SAA and hyaluronan existed as part of a complex matrix that increased the adhesion and retention of monocytes. This complex, purified by binding to a biotinylated hyaluronan binding protein affinity column, also showed monocyte chemotactic activity, which was dependent on the presence of SAA3 and hyaluronan but independent of MCP-1. We hypothesize that adipocyte hypertrophy leads to increased production of SAA and hyaluronan, which act in concert to recruit and retain monocytes, thereby leading to local inflammation in adipose tissue. PMID:17563062

Han, Chang Yeop; Subramanian, Savitha; Chan, Christina K; Omer, Mohamed; Chiba, Tsuyoshi; Wight, Thomas N; Chait, Alan

2007-06-11

136

Assessment of serum amyloid A testing of horses and its clinical application in a specialized equine practice.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To compare serum amyloid A (SAA) concentration, plasma fibrinogen concentration, total WBC count, and serum albumin-to-globulin concentration ratio (A:G ratio) in clinically normal (CN) and clinically abnormal (CA) horses. DESIGN: Prospective cohort study. ANIMALS: 111 CN horses and 101 CA horses hospitalized at a specialty clinical practice. PROCEDURES: Shortly after admission, a blood sample (20 mL) was collected from each horse for a CBC, serum protein electrophoresis, and determination of plasma fibrinogen concentration; SAA concentration was assessed with a previously validated immunoturbidometric assay. Similar testing of a subset of CA horses was conducted at various points during treatment. RESULTS: Total WBC count, A:G ratio, and SAA concentration were determined for all 212 horses; data regarding plasma fibrinogen concentration were available for 127 horses (of which 47 were CN and 80 were CA). Median SAA concentration, total WBC count, and plasma fibrinogen concentration and mean A:G ratio differed significantly between CN horses and CA horses. Correlations between these variables were poor to weak. For discrimination of CN horses from CA horses, the SAA assay had sensitivity of 53% and specificity of 94% (diagnostic accuracy, 75%); for the other assessments, accuracy ranged from 59% to 62%. Repeated assessment of SAA concentration in some CA horses revealed a gradual return to normal concentrations. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that assessment of SAA concentration can provide valuable information regarding the clinical state of horses and may be more useful for patient monitoring and as a prognostic indicator than are traditional markers of inflammation.

Belgrave RL; Dickey MM; Arheart KL; Cray C

2013-07-01

137

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Amyloid precursor protein (APP) is processed sequentially by the ?-site APP cleaving enzyme and ?-secretase to generate amyloid ? (A?) peptides, one of the hallmarks of Alzheimer’s disease. The intracellular location of A? production—endosomes or the trans-Golgi network (TGN)—remains uncertain. We i...

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

138

What's hAPPening at synapses? The role of amyloid ?-protein precursor and ?-amyloid in neurological disorders.  

UK PubMed Central (United Kingdom)

Accumulating evidence suggests that dysregulated levels of amyloid ?-protein precursor (APP) and its catabolites contribute to the impaired synaptic plasticity and seizure incidence observed in several neurological disorders, including Alzheimer's disease, fragile X syndrome, Down's syndrome, autism, epilepsy and Parkinson's disease as well as in brain injury. This review article summarizes what is known regarding the synaptic synthesis, processing and function of APP and amyloid-beta (A?), as well as discusses how these proteins could contribute to the altered synaptic plasticity and pathology of the aforementioned disorders. In addition, APP and its proteolytic fragments are emerging as biomarkers for neurological health, and pharmacological interventions that modulate their levels, such as secretase inhibitors, passive immunotherapy against A? and mGluR5 antagonists, are reviewed.

Westmark CJ

2013-04-01

139

Soluble amyloid precursor protein ? and ? in CSF in Alzheimer's disease.  

UK PubMed Central (United Kingdom)

OBJECTIVE: Cerebral accumulation of amyloid ? (A?) is a pathological hallmark of Alzheimer's disease (AD). Proteolytic processing of amyloid precursor protein (APP) by ?- or ?-secretase results in two soluble metabolites, sAPP? and sAPP?, respectively. However, previous data have shown that both ?- and ?-secretase have multiple cleavage sites. The aim of this study was to characterize the C-termini of sAPP? and sAPP? in cerebrospinal fluid (CSF) by mass spectrometry (MS) and to evaluate whether different combinations of these fragments better separate between AD patients and controls by comparing two different sAPP immunoassays. Methods: Using immunoprecipitation and high resolution MS, the APP species present in CSF were investigated. CSF levels of sAPP? and sAPP? from patients with AD (n=43) and from non-demented controls (n=44) were measured using AlphaLISA and MSD immunoassays that employ different antibodies for C-terminal recognition of sAPP?. Results: Four different C-terminal forms of sAPP were identified, sAPP?-M671, sAPP?-Y681, sAPP?-Q686, and sAPP?-K687 (APP770 numbering). Neither immunoassay for the sAPP species could separate the two patient groups. The correlation (R(2)) between the two immunoassays was 0.41 for sAPP? and 0.45 for sAPP?. Conclusion: Using high resolution MS, we show here for the first time that sAPP? in CSF ends at Q686 and K687. The findings also support the conclusion from several previous studies that sAPP? and sAPP? levels are unaltered in AD.

Brinkmalm G; Brinkmalm A; Bourgeois P; Persson R; Hansson O; Portelius E; Mercken M; Andreasson U; Parent S; Lipari F; Ohrfelt A; Bjerke M; Minthon L; Zetterberg H; Blennow K; Nutu M

2013-06-01

140

Effect of serum amyloid A on selected in vitro functions of isolated human neutrophils.  

UK PubMed Central (United Kingdom)

Serum amyloid A (SAA) is an acute phase reactant whose levels in the blood rise as part of the body's response to stress and inflammation. Previous studies have suggested that SAA may carry an anti-inflammatory potential. We evaluated the effects of SAA on human neutrophils activated by N-formyl-methionyl-leucyl-phenylalanine (fMLP) in vitro. At concentrations higher than 10 microg/mL, SAA inhibited neutrophil myeloperoxidase (MPO) release. This effect was located in the N-terminal--that is, amino acid residues 1-14--of the SAA molecule. Directed neutrophil migration was inhibited at the same SAA concentrations. Several amino acid residues (1-14, 15-104, 83-104) contributed to this effect. Neutrophil O2- production was inhibited at low concentrations of SAA (0.1 to 1 microg/ml) and was stimulated at concentrations higher than 50 microg/mL. Neutrophil O2- production induced by phorbol myristate acetate (PMA) and O2- generated by the xanthine-xanthine oxidase reaction were not affected by SAA. These results add to previous data suggesting that SAA, at concentrations recorded in the serum during inflammation, modulates neutrophil function; thus it may play a role in the down-regulation of the inflammatory process.

Gatt ME; Urieli-Shoval S; Preciado-Patt L; Fridkin M; Calco S; Azar Y; Matzner Y

1998-11-01

 
 
 
 
141

Effect of serum amyloid A on selected in vitro functions of isolated human neutrophils.  

Science.gov (United States)

Serum amyloid A (SAA) is an acute phase reactant whose levels in the blood rise as part of the body's response to stress and inflammation. Previous studies have suggested that SAA may carry an anti-inflammatory potential. We evaluated the effects of SAA on human neutrophils activated by N-formyl-methionyl-leucyl-phenylalanine (fMLP) in vitro. At concentrations higher than 10 microg/mL, SAA inhibited neutrophil myeloperoxidase (MPO) release. This effect was located in the N-terminal--that is, amino acid residues 1-14--of the SAA molecule. Directed neutrophil migration was inhibited at the same SAA concentrations. Several amino acid residues (1-14, 15-104, 83-104) contributed to this effect. Neutrophil O2- production was inhibited at low concentrations of SAA (0.1 to 1 microg/ml) and was stimulated at concentrations higher than 50 microg/mL. Neutrophil O2- production induced by phorbol myristate acetate (PMA) and O2- generated by the xanthine-xanthine oxidase reaction were not affected by SAA. These results add to previous data suggesting that SAA, at concentrations recorded in the serum during inflammation, modulates neutrophil function; thus it may play a role in the down-regulation of the inflammatory process. PMID:9823935

Gatt, M E; Urieli-Shoval, S; Preciado-Patt, L; Fridkin, M; Calco, S; Azar, Y; Matzner, Y

1998-11-01

142

Ubiquilin 1 modulates amyloid precursor protein trafficking and Abeta secretion.  

UK PubMed Central (United Kingdom)

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.

Hiltunen M; Lu A; Thomas AV; Romano DM; Kim M; Jones PB; Xie Z; Kounnas MZ; Wagner SL; Berezovska O; Hyman BT; Tesco G; Bertram L; Tanzi RE

2006-10-01

143

The Role of Phospholipase D in Amyloid Precursor Protein Processing  

Directory of Open Access Journals (Sweden)

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; Elena del Rio; Hazel Leith; Kieran C. Breen

2005-01-01

144

Suppression of amyloid-? production by 24S-hydroxycholesterol via inhibition of intracellular amyloid precursor protein trafficking.  

UK PubMed Central (United Kingdom)

Cholesterol can be converted to 24S-hydroxycholesterol (24SOHC) by neuronal cholesterol 24-hydroxylase. In mouse models of Alzheimer's disease (AD), increasing 24SOHC levels reduced AD pathology. However, mechanisms underlying the effects of 24SOHC on amyloid-? (A?) production have remained unclear. Here we report that 24SOHC treatment reduces A? production and increases endoplasmic reticulum (ER)-resident immature amyloid precursor protein (APP) levels in human neuroblastoma SH-SY5Y cells and CHO cells stably expressing human APP. Treatment with 1-10 ?M 24SOHC (equivalent to the concentrations detected in human brain homogenates) diminished A? production (IC50=4.6 ?M for A?40) without affecting secretase activities. To evaluate the intracellular APP transport, we established an in vitro vesicle formation assay. We found that APP budding via COPII vesicles was diminished by 70% in 24SOHC-treated cells. The proteomics and immunoblotting analysis revealed that 24SOHC induced the expression of glucose-regulated protein 78 (GRP78), an ER chaperone, through unfolded protein response pathways, and enhanced the formation of the APP/GRP78 complex. Knockdown of GRP78 diminished the inhibitory effects of 24SOHC on A? production. These results suggest that 24SOHC down-regulates APP trafficking via enhancement of the complex formation of APP with up-regulated GRP78 in the ER, resulting in suppression of A? production.-Urano, Y., Ochiai, S., Noguchi, N. Suppression of amyloid-? production by 24S-hydroxycholesterovia inhibition of intracellular amyloid precursor protein trafficking.

Urano Y; Ochiai S; Noguchi N

2013-07-01

145

The protein corona mediates the impact of nanomaterials and slows amyloid beta fibrillation.  

UK PubMed Central (United Kingdom)

Put your coat on: It is well recognized that the surfaces of nanomaterials in biological media are covered by various biomolecules (e.g., proteins). A) The protein corona creates a shell over different nanomaterials, regardless of their physicochemical properties (e.g., composition and shape), resulting in reduced levels of amyloid beta fibril formation. B) Pristine nanomaterials might have acceleratory effects on the fibrillation of amyloid beta.

Mahmoudi M; Monopoli MP; Rezaei M; Lynch I; Bertoli F; McManus JJ; Dawson KA

2013-03-01

146

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

Directory of Open Access Journals (Sweden)

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; Stefania Rigacci

2013-01-01

147

Protein folding and aggregation into amyloid: the interference by natural phenolic compounds.  

UK PubMed Central (United Kingdom)

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.

Stefani M; Rigacci S

2013-01-01

148

Protein folding and aggregation into amyloid: the interference by natural phenolic compounds.  

Science.gov (United States)

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. PMID:23765219

Stefani, Massimo; Rigacci, Stefania

2013-06-13

149

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-05-29

150

Amyloid-? nanotubes are associated with prion protein-dependent synaptotoxicity.  

Science.gov (United States)

Growing evidence suggests water-soluble, non-fibrillar forms of amyloid-? protein (A?) have important roles in Alzheimer's disease with toxicities mimicked by synthetic A?1-42. However, no defined toxic structures acting via specific receptors have been identified and roles of proposed receptors, such as prion protein (PrP), remain controversial. Here we quantify binding to PrP of A?1-42 after different durations of aggregation. We show PrP-binding and PrP-dependent inhibition of long-term potentiation (LTP) correlate with the presence of protofibrils. Globular oligomers bind less avidly to PrP and do not inhibit LTP, whereas fibrils inhibit LTP in a PrP-independent manner. That only certain transient A? assemblies cause PrP-dependent toxicity explains conflicting reports regarding the involvement of PrP in A?-induced impairments. We show that these protofibrils contain a defined nanotubular structure with a previously unidentified triple helical conformation. Blocking the formation of A? nanotubes or their interaction with PrP might have a role in treatment of Alzheimer's disease. PMID:24022506

Nicoll, Andrew J; Panico, Silvia; Freir, Darragh B; Wright, Daniel; Terry, Cassandra; Risse, Emmanuel; Herron, Caroline E; O'Malley, Tiernan; Wadsworth, Jonathan D F; Farrow, Mark A; Walsh, Dominic M; Saibil, Helen R; Collinge, John

2013-09-11

151

Amyloid-? nanotubes are associated with prion protein-dependent synaptotoxicity.  

UK PubMed Central (United Kingdom)

Growing evidence suggests water-soluble, non-fibrillar forms of amyloid-? protein (A?) have important roles in Alzheimer's disease with toxicities mimicked by synthetic A?1-42. However, no defined toxic structures acting via specific receptors have been identified and roles of proposed receptors, such as prion protein (PrP), remain controversial. Here we quantify binding to PrP of A?1-42 after different durations of aggregation. We show PrP-binding and PrP-dependent inhibition of long-term potentiation (LTP) correlate with the presence of protofibrils. Globular oligomers bind less avidly to PrP and do not inhibit LTP, whereas fibrils inhibit LTP in a PrP-independent manner. That only certain transient A? assemblies cause PrP-dependent toxicity explains conflicting reports regarding the involvement of PrP in A?-induced impairments. We show that these protofibrils contain a defined nanotubular structure with a previously unidentified triple helical conformation. Blocking the formation of A? nanotubes or their interaction with PrP might have a role in treatment of Alzheimer's disease.

Nicoll AJ; Panico S; Freir DB; Wright D; Terry C; Risse E; Herron CE; O'Malley T; Wadsworth JD; Farrow MA; Walsh DM; Saibil HR; Collinge J

2013-09-01

152

Interaction of reelin with amyloid precursor protein promotes neurite outgrowth.  

UK PubMed Central (United Kingdom)

The processing of amyloid precursor protein (APP) to Abeta is an important event in the pathogenesis of Alzheimer's disease, but the physiological function of APP is not well understood. Our previous work has shown that APP processing and Abeta production are regulated by the extracellular matrix protein Reelin. In the present study, we examined whether Reelin interacts with APP, and the functional consequences of that interaction in vitro. Using coimmunoprecipitation, we found that Reelin interacted with APP through the central domain of Reelin (repeats 3-6) and the E1 extracellular domain of APP. Reelin increased cell surface levels of APP and decreased endocytosis of APP in hippocampal neurons in vitro. In vivo, Reelin levels were increased in brains of APP knock-out mice and decreased in APP-overexpressing mice. RNA interference knockdown of APP decreased neurite outgrowth in vitro and prevented Reelin from increasing neurite outgrowth. Knock-out of APP or Reelin decreased dendritic arborization in cortical neurons in vivo, and APP overexpression increased dendritic arborization. APP and Reelin have previously been shown to promote neurite outgrowth through interactions with integrins. We confirmed that APP interacted with alpha3beta1 integrin, and alpha3beta1 integrin altered APP trafficking and processing. Addition of an alpha3beta1 integrin antibody prevented APP and Reelin-induced neurite outgrowth. These findings demonstrate that Reelin interacts with APP, potentially having important effects on neurite development.

Hoe HS; Lee KJ; Carney RS; Lee J; Markova A; Lee JY; Howell BW; Hyman BT; Pak DT; Bu G; Rebeck GW

2009-06-01

153

Organization of the region encompassing the human serum amyloid A (SAA) gene family on chromosome 11p15.1  

Energy Technology Data Exchange (ETDEWEB)

The four members of the human serum amyloid A protein (SAA) gene family are clustered on human chromosome 11p15.1. Three genes are differentially expressed and encode small apolipoproteins of M{sub r} 12-19 kDa: SAA1 and SAA2 encode the acute phase SAAs (A-SAAs), and SAA4 encodes the constitutively expressed SAA (C-SAA). A fourth locus, SAA3, is a pseudogene. The human SAA gene family encompasses {approximately}150 kb contained on a 900-kb yeast artificial chromosome contig. SAA1 and SAA2 are 15-20 kb apart and are arranged in divergent transcriptional orientations. SAA4 is 9 kb downstream of SAA2 and in the same orientation. SAA3 is 110 kb downstream of SAA4, and its relative orientation could not be determined. All genes known to be in the same human and mouse syntenic linkage group as SAA were mapped within the contig. Interphase FISH was used to orientate the region relative to the centromere: cen-LDHC-LDHA-SAA1-SAA2-SAA4-SAA3-TPH-D11S18=KCNC1-MYOD1-pter. 14 refs., 2 figs.

Sellar, G.C.; Whitehead, A.S. [Univ. of Dulbin (Ireland); Oghene, K. [Western General Hospital, Edinburgh (United Kingdom)] [and others

1994-09-15

154

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

DEFF Research Database (Denmark)

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

Andersen, Ove; Vilsgaard Ravn, K

1997-01-01

155

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Zinc released from excited glutamatergic neurons accelerates amyloid ? (A?) aggregation, underscoring the therapeutic potential of zinc chelation for the treatment of Alzheimer's disease (AD). Zinc can also alter A? concentration by affecting its degradation. In order to elucidate the possible role ...

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

156

Phosphatidylinositol-3-phosphate regulates sorting and processing of amyloid precursor protein through the endosomal system.  

UK PubMed Central (United Kingdom)

Defects in endosomal sorting have been implicated in Alzheimer's disease. Endosomal traffic is largely controlled by phosphatidylinositol-3-phosphate, a phosphoinositide synthesized primarily by lipid kinase Vps34. Here we show that phosphatidylinositol-3-phosphate is selectively deficient in brain tissue from humans with Alzheimer's disease and Alzheimer's disease mouse models. Silencing Vps34 causes an enlargement of neuronal endosomes, enhances the amyloidogenic processing of amyloid precursor protein in these organelles and reduces amyloid precursor protein sorting to intraluminal vesicles. This trafficking phenotype is recapitulated by silencing components of the ESCRT (Endosomal Sorting Complex Required for Transport) pathway, including the phosphatidylinositol-3-phosphate effector Hrs and Tsg101. Amyloid precursor protein is ubiquitinated, and interfering with this process by targeted mutagenesis alters sorting of amyloid precursor protein to the intraluminal vesicles of endosomes and enhances amyloid-beta peptide generation. In addition to establishing phosphatidylinositol-3-phosphate deficiency as a contributing factor in Alzheimer's disease, these results clarify the mechanisms of amyloid precursor protein trafficking through the endosomal system in normal and pathological states.

Morel E; Chamoun Z; Lasiecka ZM; Chan RB; Williamson RL; Vetanovetz C; Dall'Armi C; Simoes S; Point Du Jour KS; McCabe BD; Small SA; Di Paolo G

2013-01-01

157

Phosphatidylinositol-3-phosphate regulates sorting and processing of amyloid precursor protein through the endosomal system.  

Science.gov (United States)

Defects in endosomal sorting have been implicated in Alzheimer's disease. Endosomal traffic is largely controlled by phosphatidylinositol-3-phosphate, a phosphoinositide synthesized primarily by lipid kinase Vps34. Here we show that phosphatidylinositol-3-phosphate is selectively deficient in brain tissue from humans with Alzheimer's disease and Alzheimer's disease mouse models. Silencing Vps34 causes an enlargement of neuronal endosomes, enhances the amyloidogenic processing of amyloid precursor protein in these organelles and reduces amyloid precursor protein sorting to intraluminal vesicles. This trafficking phenotype is recapitulated by silencing components of the ESCRT (Endosomal Sorting Complex Required for Transport) pathway, including the phosphatidylinositol-3-phosphate effector Hrs and Tsg101. Amyloid precursor protein is ubiquitinated, and interfering with this process by targeted mutagenesis alters sorting of amyloid precursor protein to the intraluminal vesicles of endosomes and enhances amyloid-beta peptide generation. In addition to establishing phosphatidylinositol-3-phosphate deficiency as a contributing factor in Alzheimer's disease, these results clarify the mechanisms of amyloid precursor protein trafficking through the endosomal system in normal and pathological states. PMID:23907271

Morel, Etienne; Chamoun, Zeina; Lasiecka, Zofia M; Chan, Robin B; Williamson, Rebecca L; Vetanovetz, Christopher; Dall'armi, Claudia; Simoes, Sabrina; Point Du Jour, Kimberly S; McCabe, Brian D; Small, Scott A; Di Paolo, Gilbert

2013-08-01

158

Amyloid precursor proteins are constituents of the presynaptic active zone.  

UK PubMed Central (United Kingdom)

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. We deciphered the precise subcellular localization of APP at the nerve terminal. We demonstrate that APP and its family members, APLP1 and APLP2, are constituents of the presynaptic active zone, albeit virtually absent in synaptic vesicles (SV). Our findings open new avenues for understanding the physiological role of the mature APP proteins at synaptic contacts, implying a function in the physiology of neurotransmitter release.

Laßek M; Weingarten J; Einsfelder U; Brendel P; Müller U; Volknandt W

2013-10-01

159

Amyloid precursor proteins are constituents of the presynaptic active zone.  

Science.gov (United States)

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. We deciphered the precise subcellular localization of APP at the nerve terminal. We demonstrate that APP and its family members, APLP1 and APLP2, are constituents of the presynaptic active zone, albeit virtually absent in synaptic vesicles (SV). Our findings open new avenues for understanding the physiological role of the mature APP proteins at synaptic contacts, implying a function in the physiology of neurotransmitter release. PMID:23815291

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

2013-07-19

160

Interaction of serum amyloid A with human cystatin C--assessment of amino acid residues crucial for hCC-SAA formation (part II).  

UK PubMed Central (United Kingdom)

Secondary amyloid A (AA) amyloidosis is an important complication of some chronic inflammatory diseases, primarily rheumatoid arthritis (RA). It is a serious, potentially life-threatening disorder caused by the deposition of AA fibrils, which are derived from the circulatory, acute-phase-reactant, serum amyloid A protein (SAA). Recently, a specific interaction between SAA and the ubiquitous inhibitor of cysteine proteases--human cystatin C (hCC)--has been proved. Using a combination of selective proteolytic excision and high-resolution mass spectrometry, the binding sites in the SAA and hCC sequences were assessed as SAA(86-104) and hCC(96-102), respectively. Here, we report further details concerning the hCC-SAA interaction. With the use of affinity tests and florescent ELISA-like assays, the amino acid residues crucial for the protein interaction were determined. It was shown that all amino acid residues in the SAA sequence, essential for the formation of the protein complex, are basic ones, which suggests an electrostatic interaction character. The idea is corroborated by the fact that the most important residues in the hCC sequence are Ser-98 and Tyr-102; these residues are able to form hydrogen bonds via their hydroxyl groups. The molecular details of hCC-SAA complex formation might be helpful for the design of new compounds modulating the biological role of both proteins.

Spodzieja M; Rafalik M; Szyma?ska A; Ko?odziejczyk AS; Czaplewska P

2013-09-01

 
 
 
 
161

Molecular cloning and nucleotide sequence of cDNA for murine senile amyloid protein: nucleotide substitutions found in apolipoprotein A-II cDNA of senescence accelerated mouse (SAM).  

Digital Repository Infrastructure Vision for European Research (DRIVER)

cDNA clones encoding the murine senile amyloid protein (ASSAM) have been isolated from animal models of accelerated senescence (SAM-P/1) and from normal aging (SAM-R/1). Immunochemical and protein sequence studies revealed that apolipoprotein (apo) A-II is a serum precursor of ASSAM. A 17-base synth...

Kunisada, T; Higuchi, K; Aota, S; Takeda, T; Yamagishi, H

162

Autoinhibition of Mint1 adaptor protein regulates amyloid precursor protein binding and processing.  

UK PubMed Central (United Kingdom)

Mint adaptor proteins bind to the amyloid precursor protein (APP) and regulate APP processing associated with Alzheimer's disease; however, the molecular mechanisms underlying Mint regulation in APP binding and processing remain unclear. Biochemical, biophysical, and cellular experiments now show that the Mint1 phosphotyrosine binding (PTB) domain that binds to APP is intramolecularly inhibited by the adjacent C-terminal linker region. The crystal structure of a C-terminally extended Mint1 PTB fragment reveals that the linker region forms a short ?-helix that folds back onto the PTB domain and sterically hinders APP binding. This intramolecular interaction is disrupted by mutation of Tyr633 within the Mint1 autoinhibitory helix leading to enhanced APP binding and ?-amyloid production. Our findings suggest that an autoinhibitory mechanism in Mint1 is important for regulating APP processing and may provide novel therapies for Alzheimer's disease.

Matos MF; Xu Y; Dulubova I; Otwinowski Z; Richardson JM; Tomchick DR; Rizo J; Ho A

2012-03-01

163

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

2006-08-31

164

Amyloid precursor protein controls cholesterol turnover needed for neuronal activity.  

UK PubMed Central (United Kingdom)

Perturbation of lipid metabolism favours progression of Alzheimer disease, in which processing of Amyloid Precursor Protein (APP) has important implications. APP cleavage is tightly regulated by cholesterol and APP fragments regulate lipid homeostasis. Here, we investigated whether up or down regulation of full-length APP expression affected neuronal lipid metabolism. Expression of APP decreased HMG-CoA reductase (HMGCR)-mediated cholesterol biosynthesis and SREBP mRNA levels, while its down regulation had opposite effects. APP and SREBP1 co-immunoprecipitated and co-localized in the Golgi. This interaction prevented Site-2 protease-mediated processing of SREBP1, leading to inhibition of transcription of its target genes. A GXXXG motif in APP sequence was critical for regulation of HMGCR expression. In astrocytes, APP and SREBP1 did not interact nor did APP affect cholesterol biosynthesis. Neuronal expression of APP decreased both HMGCR and cholesterol 24-hydroxylase mRNA levels and consequently cholesterol turnover, leading to inhibition of neuronal activity, which was rescued by geranylgeraniol, generated in the mevalonate pathway, in both APP expressing and mevastatin treated neurons. We conclude that APP controls cholesterol turnover needed for neuronal activity.

Pierrot N; Tyteca D; D'auria L; Dewachter I; Gailly P; Hendrickx A; Tasiaux B; Haylani LE; Muls N; N'kuli F; Laquerrière A; Demoulin JB; Campion D; Brion JP; Courtoy PJ; Kienlen-Campard P; Octave JN

2013-04-01

165

Amyloid precursor protein controls cholesterol turnover needed for neuronal activity.  

Science.gov (United States)

Perturbation of lipid metabolism favours progression of Alzheimer disease, in which processing of Amyloid Precursor Protein (APP) has important implications. APP cleavage is tightly regulated by cholesterol and APP fragments regulate lipid homeostasis. Here, we investigated whether up or down regulation of full-length APP expression affected neuronal lipid metabolism. Expression of APP decreased HMG-CoA reductase (HMGCR)-mediated cholesterol biosynthesis and SREBP mRNA levels, while its down regulation had opposite effects. APP and SREBP1 co-immunoprecipitated and co-localized in the Golgi. This interaction prevented Site-2 protease-mediated processing of SREBP1, leading to inhibition of transcription of its target genes. A GXXXG motif in APP sequence was critical for regulation of HMGCR expression. In astrocytes, APP and SREBP1 did not interact nor did APP affect cholesterol biosynthesis. Neuronal expression of APP decreased both HMGCR and cholesterol 24-hydroxylase mRNA levels and consequently cholesterol turnover, leading to inhibition of neuronal activity, which was rescued by geranylgeraniol, generated in the mevalonate pathway, in both APP expressing and mevastatin treated neurons. We conclude that APP controls cholesterol turnover needed for neuronal activity. PMID:23554170

Pierrot, Nathalie; Tyteca, Donatienne; D'auria, Ludovic; Dewachter, Ilse; Gailly, Philippe; Hendrickx, Aurélie; Tasiaux, Bernadette; Haylani, Laetitia El; Muls, Nathalie; N'kuli, Francisca; Laquerrière, Annie; Demoulin, Jean-Baptiste; Campion, Dominique; Brion, Jean-Pierre; Courtoy, Pierre J; Kienlen-Campard, Pascal; Octave, Jean-Noël

2013-04-01

166

Amyloid precursor protein controls cholesterol turnover needed for neuronal activity  

Science.gov (United States)

Perturbation of lipid metabolism favours progression of Alzheimer disease, in which processing of Amyloid Precursor Protein (APP) has important implications. APP cleavage is tightly regulated by cholesterol and APP fragments regulate lipid homeostasis. Here, we investigated whether up or down regulation of full-length APP expression affected neuronal lipid metabolism. Expression of APP decreased HMG-CoA reductase (HMGCR)-mediated cholesterol biosynthesis and SREBP mRNA levels, while its down regulation had opposite effects. APP and SREBP1 co-immunoprecipitated and co-localized in the Golgi. This interaction prevented Site-2 protease-mediated processing of SREBP1, leading to inhibition of transcription of its target genes. A GXXXG motif in APP sequence was critical for regulation of HMGCR expression. In astrocytes, APP and SREBP1 did not interact nor did APP affect cholesterol biosynthesis. Neuronal expression of APP decreased both HMGCR and cholesterol 24-hydroxylase mRNA levels and consequently cholesterol turnover, leading to inhibition of neuronal activity, which was rescued by geranylgeraniol, generated in the mevalonate pathway, in both APP expressing and mevastatin treated neurons. We conclude that APP controls cholesterol turnover needed for neuronal activity.

Pierrot, Nathalie; Tyteca, Donatienne; D'auria, Ludovic; Dewachter, Ilse; Gailly, Philippe; Hendrickx, Aurelie; Tasiaux, Bernadette; Haylani, Laetitia El; Muls, Nathalie; N'Kuli, Francisca; Laquerriere, Annie; Demoulin, Jean-Baptiste; Campion, Dominique; Brion, Jean-Pierre; Courtoy, Pierre J; Kienlen-Campard, Pascal; Octave, Jean-Noel

2013-01-01

167

Kinetics of peptide secondary structure conversion during amyloid ?-protein fibrillogenesis.  

UK PubMed Central (United Kingdom)

Amyloid fibrils are a common component in many debilitating human neurological diseases such as Alzheimer's (AD), Parkinson's, and Creutzfeldt-Jakob, and in animal diseases such as BSE. The role of fibrillar ?? proteins in AD has stimulated interest in the kinetics of ?? fibril formation. Kinetic models that include reaction pathways and rate parameters for the various stages of the process can be helpful towards understanding the dynamics on a molecular level. Based upon experimental data, we have developed a mathematical model for the reaction pathways and determined rate parameters for peptide secondary structural conversion and aggregation during the entire fibrillogenesis process from random coil to mature fibrils, including the molecular species that accelerate the conversions. The model and the rate parameters include different molecular structural stages in the nucleation and polymerization processes and the numerical solutions yield graphs of concentrations of different molecular species versus time that are in close agreement with experimental results. The model also allows for the calculation of the time-dependent increase in aggregate size. The calculated results agree well with experimental results, and allow differences in experimental conditions to be included in the calculations. The specific steps of the model and the rate constants that are determined by fitting to experimental data provide insight on the molecular species involved in the fibril formation process.

Steckmann T; Awan Z; Gerstman BS; Chapagain PP

2012-05-01

168

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

DEFF Research Database (Denmark)

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

Horvath, A; Andersen, I

2001-01-01

169

?-Secretase-Dependent Proteolysis of Transmembrane Domain of Amyloid Precursor Protein: Successive Tri- and Tetrapeptide Release in Amyloid ?-Protein Production.  

UK PubMed Central (United Kingdom)

?-Secretase cleaves the carboxyl-terminal fragment (?CTF) of APP not only in the middle of the transmembrane domain (?-cleavage), but also at sites close to the membrane/cytoplasm boundary (?-cleavage), to produce the amyloid ? protein (A?) and the APP intracellular domain (AICD), respectively. The AICD49-99 and AICD50-99 species were identified as counterparts of the long A? species A?48 and A?49, respectively. We found that A?40 and AICD50-99 were the predominant species in cells expressing wild-type APP and presenilin, whereas the production of A?42 and AICD49-99 was enhanced in cells expressing familial Alzheimer's disease mutants of APP and presenilin. These long A? species were identified in cell lysates and mouse brain extracts, which suggests that ?-cleavage is the first cleavage of ?CTF to produce A? by ?-secretase. Here, we review the progress of research on the mechanism underlying the proteolysis of the APP transmembrane domain based on tri- and tetrapeptide release.

Takami M; Funamoto S

2012-01-01

170

?-Secretase-Dependent Proteolysis of Transmembrane Domain of Amyloid Precursor Protein: Successive Tri- and Tetrapeptide Release in Amyloid ?-Protein Production.  

Science.gov (United States)

?-Secretase cleaves the carboxyl-terminal fragment (?CTF) of APP not only in the middle of the transmembrane domain (?-cleavage), but also at sites close to the membrane/cytoplasm boundary (?-cleavage), to produce the amyloid ? protein (A?) and the APP intracellular domain (AICD), respectively. The AICD49-99 and AICD50-99 species were identified as counterparts of the long A? species A?48 and A?49, respectively. We found that A?40 and AICD50-99 were the predominant species in cells expressing wild-type APP and presenilin, whereas the production of A?42 and AICD49-99 was enhanced in cells expressing familial Alzheimer's disease mutants of APP and presenilin. These long A? species were identified in cell lysates and mouse brain extracts, which suggests that ?-cleavage is the first cleavage of ?CTF to produce A? by ?-secretase. Here, we review the progress of research on the mechanism underlying the proteolysis of the APP transmembrane domain based on tri- and tetrapeptide release. PMID:23346458

Takami, Mako; Funamoto, Satoru

2012-12-31

171

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

Science.gov (United States)

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

172

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

UK PubMed Central (United Kingdom)

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.

Cai X; Freedman SB; Witting PK

2013-09-01

173

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

UK PubMed Central (United Kingdom)

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.

Revett TJ; Baker GB; Jhamandas J; Kar S

2013-01-01

174

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

UK PubMed Central (United Kingdom)

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.

Kitayama H; Yoshimura Y; So M; Sakurai K; Yagi H; Goto Y

2013-10-01

175

Serum amyloid A upsurge precedes standard biomarkers of hepatotoxicity in ritodrine-injected mice.  

UK PubMed Central (United Kingdom)

The tocolytic agent ritodrine acts on the ?2-adrenoceptor and is an effective treatment option for preterm labor. However, several adverse effects of ritodrine therapy, including liver damage, have been noted. To elucidate the underlying mechanisms of ritodrine-induced adverse effects, development of sensitive biomarkers of these adverse events is necessary. Here, we report the development and analysis of an animal model of ritodrine-induced liver damage. Female mice received daily ritodrine injections for 2 weeks; liver samples were then collected and subjected to DNA microarray analysis. Ritodrine significantly altered the expression of genes related to steroid and lipid metabolism, as well as the metabolism of ritodrine itself. Importantly, expression of the acute-phase reactant serum amyloid A (SAA) significantly increased after ritodrine injection, with values indicating the largest fold-change. This large increase in blood SAA levels serves as a more sensitive biomarker than conventional liver enzymes, such as aspartate aminotransferase and alanine aminotransferase. The increase in SAA expression is specific to ritodrine-induced liver damage, because SAA expression was not induced by other hepatotoxic drugs such as acetaminophen, valproic acid, or metformin. Our in vitro studies showed that cyclic adenosine 3',5'-monophosphate (cAMP) accumulation was not a primary cause of the ritodrine-induced SAA increase. Instead, SAA expression was enhanced by indirect phosphorylation of the signal transducer and activator of transcription-3 (STAT3) mediated by interleukin-6. Therefore, our study provides a method for sensitive and early detection of hepatic injury, and may thus help preclude serious liver damage due to ritodrine use in preterm labor.

Tsuchiya H; Sato J; Tsuda H; Fujiwara Y; Yamada T; Fujimura A; Koshimizu TA

2013-03-01

176

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

UK PubMed Central (United Kingdom)

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 t(1/2) 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.

Dillingh MR; van den Blink B; Moerland M; van Dongen MG; Kleinjan A; Wijsenbeek MS; Lupher ML Jr; Harper DM; Getsy JA; Hoogsteden HC; Burggraaf J

2013-02-01

177

Promotion of ?-amyloid production by C-reactive protein and its implications in the early pathogenesis of Alzheimer's disease.  

UK PubMed Central (United Kingdom)

C-reactive protein (CRP) and ?-amyloid protein (A?) are involved in the development of Alzheimer's disease (AD). However, the relationship between CRP and A? production is unclear. In vitro and in vivo experiments were performed to investigate the association of CRP with A? production. Using the rat adrenal pheochromocytoma cell line (PC12 cells) to mimic neurons, cytotoxicity was evaluated by cell viability and supernatant lactate dehydrogenase (LDH) activity. The levels of amyloid precursor protein (APP), beta-site APP cleaving enzyme (BACE-1), and presenilins (PS-1 and PS-2) were investigated using real-time polymerase chain reaction and Western blotting analysis. A?1-42 was measured by enzyme-linked immunosorbent assay. The relevance of CRP and A? as well as potential mechanisms were studied using APP/PS1 transgenic (Tg) mice. Treatment with 0.5-4.0 ?M CRP for 48 h decreased cell viability and increased LDH leakage in PC12 cells. Incubation with CRP at a sub-toxic concentration of 0.2 ?M increased the mRNA levels of APP, BACE-1, PS-1, and PS-2, as well as A?1-42 production. CRP inhibitor reversed the CRP-induced upregulations of the mRNA levels of APP, BACE-1, PS-1, and PS-2, and the protein levels of APP, BACE-1, PS-1, and A?1-42, but did not reversed A?1-42 cytotoxicity. The cerebral levels of CRP and A?1-42 in APP/PS1 Tg mice were positively correlated, accompanied with the elevated mRNA expressions of serum amyloid P component (SAP), complement component 1q (C1q), and tumor necrosis factor-? (TNF-?). These results suggest that CRP cytotoxicity is associated with A? formation and A?-related markers expressions; CRP and A? were relevant in early-stage AD; CRP may be an important trigger in AD pathogenesis.

Bi BT; Lin HB; Cheng YF; Zhou H; Lin T; Zhang MZ; Li TJ; Xu JP

2012-02-01

178

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

UK PubMed Central (United Kingdom)

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.

Chen L; Une Y; Higuchi K; Mori M

2012-01-01

179

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

2011-10-10

180

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 formation significantly. Furthermore, we monitored the change in apoptosis and reactive oxygen species (ROS) level upon curcumin treatment in mouse neuroblastoma cells (N2a). Curcumin effectively rescues the cells from apoptosis and decreases the ROS level caused by subsequent co-incubation with prion amyloid fibrils. The assays in cell-free mPrP and in N2a cells of this work verified the promising effect of curcumin on the prevention of transmissible neurodegenerative diseases.

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

2013-01-01

 
 
 
 
181

Expression and processing of fluorescent fusion proteins of amyloid precursor protein (APP).  

UK PubMed Central (United Kingdom)

Processing of ?-amyloid precursor protein (APP) by ?- and ?-secretases in neurons produces amyloid-? (A?), whose excess accumulation leads to Alzheimer's disease (AD). Knowledge on subcellular trafficking pathways of APP and its fragments is important for the understanding of AD pathogenesis. We designed fusion proteins comprising a C-terminal fragment of APP (app) and fluorescent proteins GFP (G) and DsRed (D) to permit the tracking of the fusion proteins and fragments in cells. CAD cells expressing these proteins emitted colocalized green and red fluorescence and produce ectodomains, sGapp and sRapp, and A?, whose level was reduced by inhibitors of ?- and ?-secretases. The presence of GappR in endosomes was observed via colocalization with Rab5. These observations indicated that the fusion proteins were membrane inserted, transported in vesicles and proteolytically processed by the same mechanism for APP. By attenuating fusion protein synthesis with cycloheximide, individual fluorescent colors from the C-terminus of the fusion proteins appeared in the cytosol which was strongly suppressed by ?-secretase inhibitor, suggesting that the ectodomains exit the cell rapidly (t1/2 about 20min) while the C-terminal fragments were retained longer in cells. In live cells, we observed the fluorescence of the ectodomains located between parental fusion proteins and plasma membrane, suggesting that these ectodomain positions are part of their secretion pathway. Our results indicate that the native ectodomain does not play a decisive role for the key features of APP trafficking and processing and the new fusion proteins may lead to novel insights in intracellular activities of APP.

Coughlan K; Huang X; He X; Chung CH; Li G; Tang J

2013-06-01

182

Cudrania cochinchinensis attenuates amyloid ? protein-mediated microglial activation and promotes glia-related clearance of amyloid ? protein.  

UK PubMed Central (United Kingdom)

BACKGROUND: Microglial inflammation may significantly contribute to the pathology of Alzheimer's disease. To examine the potential of Cudrania cochinchinensis to ameliorate amyloid ? protein (A?)-induced microglia activation, BV-2 microglial cell line, and the ramified microglia in the primary glial mixed cultured were employed. RESULTS: Lipopolysaccharide (LPS), Interferon-? (IFN-?), fibrillary A? (fA?), or oligomeric A? (oA?) were used to activate microglia. LPS and IFN-?, but not A?s, activated BV-2 cells to produce nitric oxide through an increase in inducible nitric oxide synthase (iNOS) expression without significant effects on cell viability of microglia. fA?, but not oA?, enhanced the IFN-?-stimulated nitric oxide production and iNOS expression.The ethanol/water extracts of Cudrania cochinchinensis (CC-EW) and the purified isolated components (i.e. CCA to CCF) effectively reduced the nitric oxide production and iNOS expression stimulated by IFN-? combined with fA?. On the other hand, oA? effectively activated the ramified microglia in mixed glial culture by observing the morphological alteration of the microglia from ramified to amoeboid. CC-EW and CCB effectively prohibit the A?-mediated morphological change of microglia. Furthermore, CC-EW and CCB effectively decreased A? deposition and remained A? in the conditioned medium suggesting the effect of CC-EW and CCB on promoting A? clearance. Results are expressed as mean ± S.D. and were analyzed by ANOVA with post-hoc multiple comparisons with a Bonferroni test. CONCLUSIONS: The components of Cudrania cochinchinensis including CC-EW and CCB are potential for novel therapeutic intervention for Alzheimer's disease.

Wang CJ; Chen CC; Tsay HJ; Chiang FY; Wu MF; Shiao YJ

2013-01-01

183

Cudrania cochinchinensis attenuates amyloid ? protein-mediated microglial activation and promotes glia-related clearance of amyloid ? protein  

Science.gov (United States)

Background Microglial inflammation may significantly contribute to the pathology of Alzheimer’s disease. To examine the potential of Cudrania cochinchinensis to ameliorate amyloid ? protein (A?)-induced microglia activation, BV-2 microglial cell line, and the ramified microglia in the primary glial mixed cultured were employed. Results Lipopolysaccharide (LPS), Interferon-? (IFN-?), fibrillary A? (fA?), or oligomeric A? (oA?) were used to activate microglia. LPS and IFN-?, but not A?s, activated BV-2 cells to produce nitric oxide through an increase in inducible nitric oxide synthase (iNOS) expression without significant effects on cell viability of microglia. fA?, but not oA?, enhanced the IFN-?-stimulated nitric oxide production and iNOS expression. The ethanol/water extracts of Cudrania cochinchinensis (CC-EW) and the purified isolated components (i.e. CCA to CCF) effectively reduced the nitric oxide production and iNOS expression stimulated by IFN-? combined with fA?. On the other hand, oA? effectively activated the ramified microglia in mixed glial culture by observing the morphological alteration of the microglia from ramified to amoeboid. CC-EW and CCB effectively prohibit the A?-mediated morphological change of microglia. Furthermore, CC-EW and CCB effectively decreased A? deposition and remained A? in the conditioned medium suggesting the effect of CC-EW and CCB on promoting A? clearance. Results are expressed as mean?±?S.D. and were analyzed by ANOVA with post-hoc multiple comparisons with a Bonferroni test. Conclusions The components of Cudrania cochinchinensis including CC-EW and CCB are potential for novel therapeutic intervention for Alzheimer’s disease.

2013-01-01

184

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

2012-01-01

185

Amyloid precursor proteins interact with the heterotrimeric G protein Go in the control of neuronal migration.  

UK PubMed Central (United Kingdom)

Amyloid precursor protein (APP) belongs to a family of evolutionarily conserved transmembrane glycoproteins that has been proposed to regulate multiple aspects of cell motility in the nervous system. Although APP is best known as the source of ?-amyloid fragments (A?) that accumulate in Alzheimer's disease, perturbations affecting normal APP signaling events may also contribute to disease progression. Previous in vitro studies showed that interactions between APP and the heterotrimeric G protein Go?-regulated Go? activity and Go-dependent apoptotic responses, independent of A?. However, evidence for authentic APP-Go interactions within the healthy nervous system has been lacking. To address this issue, we have used a combination of in vitro and in vivo strategies to show that endogenously expressed APP family proteins colocalize with Go? in both insect and mammalian nervous systems, including human brain. Using biochemical, pharmacological, and Bimolecular Fluorescence Complementation assays, we have shown that insect APP (APPL) directly interacts with Go? in cell culture and at synaptic terminals within the insect brain, and that this interaction is regulated by Go? activity. We have also adapted a well characterized assay of neuronal migration in the hawkmoth Manduca to show that perturbations affecting APPL and Go? signaling induce the same unique pattern of ectopic, inappropriate growth and migration, analogous to defective migration patterns seen in mice lacking all APP family proteins. These results support the model that APP and its orthologs regulate conserved aspects of neuronal migration and outgrowth in the nervous system by functioning as unconventional Go?-coupled receptors.

Ramaker JM; Swanson TL; Copenhaver PF

2013-06-01

186

The platelet amyloid precursor protein ratio as a diagnostic marker for Alzheimer's disease in Thai patients.  

UK PubMed Central (United Kingdom)

The platelet amyloid precursor protein (APP) ratio has recently been shown to be a promising diagnostic marker for Alzheimer's disease (AD). To evaluate its usefulness in Thai patients, platelet APP was analyzed by immunoblotting. The APP ratio was calculated as the ratio of the combined band density of the 120-kD and 130-kD isoforms compared to that of the 110-kD isoform. The mean ages (and ranges) of 27 normal and 13 AD-affected subjects were 68.3 (60-84) and 79.3 (70-97) years, respectively. The Thai Mental State Examination (TMSE) scores demonstrated that the AD patients had significantly poorer cognitive functions than the normal subjects, with mean TMSE scores of 20.3 and 27.6 (maximum score of 30 points), respectively (p<0.05). The platelet APP ratios of the AD patients were significantly lower than those of normal subjects: values (mean ± standard deviation) were 7.32 ± 1.29 and 9.13 ± 3.00, respectively (p<0.05) for AD patients and normal subjects. However, the ranges of the APP ratios from both groups markedly overlapped, which precluded the establishment of a cutoff level to differentiate between the AD and normal subjects. In addition, no significant correlations were observed between the platelet APP ratio and the TMSE score or between the APP ratio and the serum cholesterol in this study, in contrast to previous reports.

Srisawat C; Junnu S; Peerapittayamongkol C; Futrakul A; Soi-ampornkul R; Senanarong V; Praditsuwan R; Assantachai P; Neungton N

2013-05-01

187

The platelet amyloid precursor protein ratio as a diagnostic marker for Alzheimer's disease in Thai patients.  

Science.gov (United States)

The platelet amyloid precursor protein (APP) ratio has recently been shown to be a promising diagnostic marker for Alzheimer's disease (AD). To evaluate its usefulness in Thai patients, platelet APP was analyzed by immunoblotting. The APP ratio was calculated as the ratio of the combined band density of the 120-kD and 130-kD isoforms compared to that of the 110-kD isoform. The mean ages (and ranges) of 27 normal and 13 AD-affected subjects were 68.3 (60-84) and 79.3 (70-97) years, respectively. The Thai Mental State Examination (TMSE) scores demonstrated that the AD patients had significantly poorer cognitive functions than the normal subjects, with mean TMSE scores of 20.3 and 27.6 (maximum score of 30 points), respectively (p<0.05). The platelet APP ratios of the AD patients were significantly lower than those of normal subjects: values (mean ± standard deviation) were 7.32 ± 1.29 and 9.13 ± 3.00, respectively (p<0.05) for AD patients and normal subjects. However, the ranges of the APP ratios from both groups markedly overlapped, which precluded the establishment of a cutoff level to differentiate between the AD and normal subjects. In addition, no significant correlations were observed between the platelet APP ratio and the TMSE score or between the APP ratio and the serum cholesterol in this study, in contrast to previous reports. PMID:23453155

Srisawat, Chatchawan; Junnu, Sarawut; Peerapittayamongkol, Chayanon; Futrakul, Aree; Soi-ampornkul, Rungtip; Senanarong, Vorapun; Praditsuwan, Rungnirand; Assantachai, Prasert; Neungton, Neelobol

2013-02-27

188

Serum amyloid A is a growth factor for 3T3-L1 adipocytes, inhibits differentiation and promotes insulin resistance.  

UK PubMed Central (United Kingdom)

BACKGROUND/OBJECTIVES: Serum amyloid A (SAA) is an acute-phase protein that has been recently correlated with obesity and insulin resistance. Therefore, we first examined whether human recombinant SAA (rSAA) could affect the proliferation, differentiation and metabolism of 3T3-L1 preadipocytes. DESIGN: Preadipocytes were treated with rSAA and analyzed for changes in viability and [³H-methyl]-thymidine incorporation as well as cell cycle perturbations using flow cytometry analysis. The mRNA expression profiles of adipogenic factors during the differentiation protocol were also analyzed using real-time PCR. After differentiation, 2-deoxy-[1,2-³H]-glucose uptake and glycerol release were evaluated. RESULTS: rSAA treatment caused a 2.6-fold increase in cell proliferation, which was consistent with the results from flow cytometry showing that rSAA treatment augmented the percentage of cells in the S phase (60.9±0.54%) compared with the control cells (39.8±2.2%, (***) P<0.001). The rSAA-induced cell proliferation was mediated by the ERK1/2 signaling pathway, which was assessed by pretreatment with the inhibitor PD98059. However, the exposure of 3T3-L1 cells to rSAA during the differentiation process resulted in attenuated adipogenesis and decreased expression of adipogenesis-related factors. During the first 72?h of differentiation, rSAA inhibited the differentiation process by altering the mRNA expression kinetics of adipogenic transcription factors and proteins, such as PPAR?2 (peroxisome proliferator-activated receptor ? 2), C/EBP? (CCAAT/enhancer-binding protein ?) and GLUT4. rSAA prevented the intracellular accumulation of lipids and, in fully differentiated cells, increased lipolysis and prevented 2-deoxy-[1,2-³H]-glucose uptake, which favors insulin resistance. Additionally, rSAA stimulated the secretion of proinflammatory cytokines interleukin 6 and tumor necrosis factor ?, and upregulated SAA3 mRNA expression during adipogenesis. CONCLUSIONS: We showed that rSAA enhanced proliferation and inhibited differentiation in 3T3-L1 preadipocytes and altered insulin sensitivity in differentiated cells. These results highlight the complex role of SAA in the adipogenic process and support a direct link between obesity and its co-morbidities such as type II diabetes.

Filippin-Monteiro FB; de Oliveira EM; Sandri S; Knebel FH; Albuquerque RC; Campa A

2012-08-01

189

[Blood serum proteins during sport training  

UK PubMed Central (United Kingdom)

Disc-electrophoresis in polyacrylamide gel, differential temperature-perturbation spectrophotometry radial immunodiffusion were used to study the effect of training on blood serum proteins in bicyclists and athletes in the preparation period and during competitions. A significant increase in the total amount of proteins and albumins in blood serum was found after physical loading. Polymerization of albumin in polyacrylamide gel is observed for highly trained sportsmen at the beginning of the preparation period. It is shown that training loads do not affect the tyrosyl availability in the albumin molecule.

Efimenko AM; Tolkacheva NV; Ostolovskii EM; Stanevich AV

1978-11-01

190

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

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FE65 binds to the Alzheimer amyloid precursor protein (APP), but the function of this interaction has not been identified. Here, we report that APP and FE65 are involved in regulation of cell movement. APP and FE65 colocalize with actin and Mena, an Abl-associated signaling protein thought to regula...

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

191

Adaptor protein 2–mediated endocytosis of the ?-secretase BACE1 is dispensable for amyloid precursor protein processing  

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An adaptor protein complex, AP-2, is involved in the endocytosis of ?-secretase (BACE1) via the clathrin-dependent machinery. Endosomal targeting of either the amyloid precursor protein (APP) and/or BACE1 is expendable for the amyloidogenic processing of APP.

Prabhu, Yogikala; Burgos, Patricia V.; Schindler, Christina; Farías, Ginny G.; Magadár, Javier G.; Bonifacino, Juan S.

192

Neuronal activity and secreted amyloid ? lead to altered amyloid ? precursor protein and presenilin 1 interactions.  

UK PubMed Central (United Kingdom)

Deposition of amyloid ? (A?) containing plaques in the brain is one of the neuropathological hallmarks of Alzheimer's disease (AD). It has been suggested that modulation of neuronal activity may alter A? production in the brain. We postulate that these changes in A? production are due to changes in the rate-limiting step of A? generation, APP cleavage by ?-secretase. By combining biochemical approaches with fluorescence lifetime imaging microscopy, we found that neuronal inhibition decreases endogenous APP and PS1 interactions, which correlates with reduced A? production. By contrast, neuronal activation had a two-phase effect: it initially enhanced APP-PS1 interaction leading to increased A? production, which followed by a decrease in the APP and PS1 proximity/interaction. Accordingly, treatment of neurons with naturally secreted A? isolated from AD brain or with synthetic A? resulted in reduced APP and PS1 proximity. Moreover, applying low concentration of A?(42) to cultured neurons inhibited de novo A? synthesis. These data provide evidence that neuronal activity regulates endogenous APP-PS1 interactions, and suggest a model of a product-enzyme negative feedback. Thus, under normal physiological conditions A? may impact its own production by modifying ?-secretase cleavage of APP. Disruption of this negative modulation may cause A? overproduction leading to neurotoxicity.

Li X; Uemura K; Hashimoto T; Nasser-Ghodsi N; Arimon M; Lill CM; Palazzolo I; Krainc D; Hyman BT; Berezovska O

2013-02-01

193

Cellular localization and mechanism of amyloid precursor protein (APP) homodimer formation in an oxidizing environment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The amyloid precursor protein (APP) is a type I transmembrane glycoprotein, which resembles a cell surface receptor, comprising a large ectodomain, a single spanning transmembrane part and a short C-terminal, cytoplasmic domain. It belongs to a conserved gene family, with over 17 members, including ...

Isbert, Simone

194

Hypersensitivity to seizures in beta-amyloid precursor protein deficient mice  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Secreted forms of the ?-amyloid precursor protein (?-APP) have neuroprotective properties in vitro and may be involved in the containment of neuronal excitation. To test whether loss of secreted forms of ?-APP (sAPPs) may enhance excitotoxic responses, we injected mice homozygous for a targeted muta...

Steinbach, Joachim P.; Müller, Ulrike; Leist, Marcel; Li, Zhi-Wei; Nicotera, Pierluigi; Aguzzi, Adriano

195

Large Proteins Have a Great Tendency to Aggregate but a Low Propensity to Form Amyloid Fibrils  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The assembly of soluble proteins into ordered fibrillar aggregates with cross-? structure is an essential event of many human diseases. The polypeptides undergoing aggregation are generally small in size. To explore if the small size is a primary determinant for the formation of amyloids under patho...

Ramshini, Hassan; Parrini, Claudia; Relini, Annalisa; Zampagni, Mariagioia; Mannini, Benedetta; Pesce, Alessandra

196

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 e...

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

197

The Role of ?-Amyloid Protein in Synaptic Function: Implications for Alzheimer’s Disease Therapy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by progressive and irreversible loss of memory and other cognitive functions. Substantial evidence based on genetic, neuropathological and biochemical data has established the central role of ?-amyloid protein (?AP) in this patho...

Peña, F; Gutiérrez-Lerma, AI; Quiroz-Baez, R; Arias, C

198

Transcriptional Regulation of BACE1, the ?-Amyloid Precursor Protein ?-Secretase, by Sp1  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Proteolytic processing of the ?-amyloid precursor protein (APP) at the ? site is essential to generate A?. BACE1, the major ?-secretase involved in cleaving APP, has been identified as a type 1 membrane-associated aspartyl protease. We have cloned a 2.1-kb fragment upstream of the human BACE1 gene a...

Christensen, Michelle A.; Zhou, Weihui; Qing, Hong; Lehman, Anna; Philipsen, Sjaak; Song, Weihong

199

Advances in the beta-amyloid precursor protein of Alzheimer^s disease  

UK PubMed Central (United Kingdom)

Alzheimer^s disease (AD) is a primary neurodegenerative disorder mainly affectin g aged people over 60 years old. It is characterized by extracellular senile plaques (SPs) and intracellular n eurofibrillary tangles (NFTs) in patients^ brains. The major component of SP is beta-amyloid peptide (betaA) with molecular weight of about 4 ku which is a neurotoxic derivative of beta-amyloid precursor protein (APP) and can cause cell damage mainly through oxidative stress and being able to form calcium channels in lipid bulayers.

Chen Peili; Tong Tanjun; Zhang Zongyu

1999-01-01

200

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Amyloidogenic processing of the amyloid precursor protein (APP) generates a large secreted ectodomain fragment (APPs?), ?-amyloid (A?) peptides, and an APP intracellular domain (AICD). Whereas A? is viewed as critical for Alzheimer's disease pathogenesis, the role of other APP processing products re...

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

 
 
 
 
201

Presence of Sodium Dodecyl Sulfate-Stable Amyloid ?-Protein Dimers in the Hippocampus CA1 Not Exhibiting Neurofibrillary Tangle Formation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The amyloid cascade hypothesis of Alzheimer’s disease postulates that accumulation of amyloid ?-protein (A?) precedes neurofibrillary tangle formation or neuronal loss in the cortex. Although this temporal profile has been proved in the neocortex by silver staining and immunocytochemical methods, CA...

Funato, Hiromasa; Enya, Miho; Yoshimura, Masahiro; Morishima-Kawashima, Maho; Ihara, Yasuo

202

Wet-spinning of amyloid protein nanofibers into multifunctional high-performance biofibers.  

Science.gov (United States)

Amyloid nanofibers derived from hen egg white lysozyme were processed into macroscopic fibers in a wet-spinning process based on interfacial polyion complexation using a polyanionic polysaccharide as cross-linker. As a result of their amyloid nanostructure, the hierarchically self-assembled protein fibers have a stiffness of up to 14 GPa and a tensile strength of up to 326 MPa. Fine-tuning of the polyelectrolytic interactions via pH allows to trigger the release of small molecules, as demonstrated with riboflavin-5'-phophate. The amyloid fibrils, highly oriented within the gellan gum matrix, were mineralized with calcium phosphate, mimicking the fibrolamellar structure of bone. The formed mineral crystals are highly oriented along the nanofibers, thus resulting in a 9-fold increase in fiber stiffness. PMID:21859156

Meier, Christoph; Welland, Mark E

2011-09-01

203

Wet-spinning of amyloid protein nanofibers into multifunctional high-performance biofibers.  

UK PubMed Central (United Kingdom)

Amyloid nanofibers derived from hen egg white lysozyme were processed into macroscopic fibers in a wet-spinning process based on interfacial polyion complexation using a polyanionic polysaccharide as cross-linker. As a result of their amyloid nanostructure, the hierarchically self-assembled protein fibers have a stiffness of up to 14 GPa and a tensile strength of up to 326 MPa. Fine-tuning of the polyelectrolytic interactions via pH allows to trigger the release of small molecules, as demonstrated with riboflavin-5'-phophate. The amyloid fibrils, highly oriented within the gellan gum matrix, were mineralized with calcium phosphate, mimicking the fibrolamellar structure of bone. The formed mineral crystals are highly oriented along the nanofibers, thus resulting in a 9-fold increase in fiber stiffness.

Meier C; Welland ME

2011-10-01

204

The Transcriptionally Active Amyloid Precursor Protein (APP) Intracellular Domain Is Preferentially Produced from the 695 Isoform of APP in a ?-Secretase-dependent Pathway*?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Amyloidogenic processing of the amyloid precursor protein (APP) by ?- and ?-secretases generates several biologically active products, including amyloid-? (A?) and the APP intracellular domain (AICD). AICD regulates transcription of several neuronal genes, especially the A?-degrading enzyme, neprily...

Belyaev, Nikolai D.; Kellett, Katherine A. B.; Beckett, Caroline; Makova, Natalia Z.; Revett, Timothy J.; Nalivaeva, Natalia N.

205

Serum proteins analysis by capillary electrophoresis.  

Science.gov (United States)

The purpose of this study was to evaluate the efficacy of multi-capillary electrophoresis instrument in clinical laboratory. An automated clinical capillary electrophoresis system was evaluated for performing serum proteins electrophoresis and immuno-fixation electrophoresis by subtraction. In this study the performance of capillary electrophoresis was compared with the cellulose acetate membrane electrophoresis and agarose gel immunofixation electrophoresis for serum proteins. The results of capillary electrophoresis and cellulose acetate membrane electrophoresis were good (r=0.89?0.97) for protein fractions and A/G ratio except for ?-gobulin fraction (r=0.60). Both within-run and day to day precisions (CVs) of assay results for 5 main fractions and A/G ratio (n=10) were between 0.3?6.3%. The reference ranges of serum protein fractions obtained from 200 healthy individuals by cellulose acetate membrane electrophoresis were almost equal to that of capillary electrophoresis except for ?-1 globulin fraction. No significant difference of electropherograms between cellulose acetate electrophoresis and capillary electrophoresis was observed in the abnormal serum such as presence of bilirubin (immunofixation electrophoresis by subtraction identifying 30 monoclonal gammmopathy patient samples. PMID:23105313

Uji, Y; Okabe, H

2001-07-01

206

SERUM PROTEINS, TRANSAMINASES AND PHOSPHATASES IN MALNUTRITION  

Directory of Open Access Journals (Sweden)

Full Text Available The levels of serum tota1 protein, albumin, transaminases and phosphatases were estimated in a group of children with severe Marasmus or mild malnutrition in order to identify some of the associated deficiencies in these syndromes. The biochemical pattern was similar in the normal and malnourished children.

H. Mohammadiha; J. Nahani; M. Rafii; N. Mohagheghpour.

1976-01-01

207

Role of phosphatidylinositol clathrin assembly lymphoid-myeloid leukemia (PICALM) in intracellular amyloid precursor protein (APP) processing and amyloid plaque pathogenesis.  

UK PubMed Central (United Kingdom)

One of the pathological hallmarks of Alzheimer disease is the accumulation of amyloid plaques in the extracellular space in the brain. Amyloid plaques are primarily composed of aggregated amyloid ? peptide (A?), a proteolytic fragment of the transmembrane amyloid precursor protein (APP). For APP to be proteolytically cleaved into A?, it must be internalized into the cell and trafficked to endosomes where specific protease complexes can cleave APP. Several recent genome-wide association studies have reported that several single nucleotide polymorphisms (SNPs) in the phosphatidylinositol clathrin assembly lymphoid-myeloid leukemia (PICALM) gene were significantly associated with Alzheimer disease, suggesting a role in APP endocytosis and A? generation. Here, we show that PICALM co-localizes with APP in intracellular vesicles of N2a-APP cells after endocytosis is initiated. PICALM knockdown resulted in reduced APP internalization and A? generation. Conversely, PICALM overexpression increased APP internalization and A? production. In vivo, PICALM was found to be expressed in neurons and co-localized with APP throughout the cortex and hippocampus in APP/PS1 mice. PICALM expression was altered using AAV8 gene transfer of PICALM shRNA or PICALM cDNA into the hippocampus of 6-month-old APP/PS1 mice. PICALM knockdown decreased soluble and insoluble A? levels and amyloid plaque load in the hippocampus. Conversely, PICALM overexpression increased A? levels and amyloid plaque load. These data indicate that PICALM, an adaptor protein involved in clathrin-mediated endocytosis, regulates APP internalization and subsequent A? generation. PICALM contributes to amyloid plaque load in brain likely via its effect on A? metabolism.

Xiao Q; Gil SC; Yan P; Wang Y; Han S; Gonzales E; Perez R; Cirrito JR; Lee JM

2012-06-01

208

Role of phosphatidylinositol clathrin assembly lymphoid-myeloid leukemia (PICALM) in intracellular amyloid precursor protein (APP) processing and amyloid plaque pathogenesis.  

Science.gov (United States)

One of the pathological hallmarks of Alzheimer disease is the accumulation of amyloid plaques in the extracellular space in the brain. Amyloid plaques are primarily composed of aggregated amyloid ? peptide (A?), a proteolytic fragment of the transmembrane amyloid precursor protein (APP). For APP to be proteolytically cleaved into A?, it must be internalized into the cell and trafficked to endosomes where specific protease complexes can cleave APP. Several recent genome-wide association studies have reported that several single nucleotide polymorphisms (SNPs) in the phosphatidylinositol clathrin assembly lymphoid-myeloid leukemia (PICALM) gene were significantly associated with Alzheimer disease, suggesting a role in APP endocytosis and A? generation. Here, we show that PICALM co-localizes with APP in intracellular vesicles of N2a-APP cells after endocytosis is initiated. PICALM knockdown resulted in reduced APP internalization and A? generation. Conversely, PICALM overexpression increased APP internalization and A? production. In vivo, PICALM was found to be expressed in neurons and co-localized with APP throughout the cortex and hippocampus in APP/PS1 mice. PICALM expression was altered using AAV8 gene transfer of PICALM shRNA or PICALM cDNA into the hippocampus of 6-month-old APP/PS1 mice. PICALM knockdown decreased soluble and insoluble A? levels and amyloid plaque load in the hippocampus. Conversely, PICALM overexpression increased A? levels and amyloid plaque load. These data indicate that PICALM, an adaptor protein involved in clathrin-mediated endocytosis, regulates APP internalization and subsequent A? generation. PICALM contributes to amyloid plaque load in brain likely via its effect on A? metabolism. PMID:22539346

Xiao, Qingli; Gil, So-Chon; Yan, Ping; Wang, Yan; Han, Sharon; Gonzales, Ernie; Perez, Ronaldo; Cirrito, John R; Lee, Jin-Moo

2012-04-26

209

Synthetic peptide homologous to ? protein from Alzheimer's disease forms amyloid-like fibrils in vitro  

International Nuclear Information System (INIS)

Progressive amyloid deposition in senile plaques and cortical blood vessels may play a central role in the pathogenesis of Alzheimer's disease. The authors have used x-ray diffraction and electron microscopy to study the molecular organization and morphology of macromolecular assemblies formed by three synthetic peptides homologous to ? protein of brain amyloid: ?-(1-28), residues 1-28 of the ? protein; [Ala1-?-(1-28), ?-(1-28) with alanine substituted for lysine at position 16; and ?-(18-28), residues 18-28 of the ? protein. ?-(1-28) readily formed fibrils in vitro that were similar in ultrastructure to the in vivo amyloid and aggregated into large bundles resembling those of senile plaque cores. X-ray patterns from partially dried, oriented pellets showed a cross-?-conformation. [Ala16]?-(1-28) formed ?-pleated sheet assemblies that were dissimilar to in vivo fibrils. The width of the 10-A spacing indicated stacks of about six sheets. Thus, substitution of the uncharged alanine for the positively charged lysine in the ?-strand region enhances the packing of the sheets and dramatically alters the type of macromolecular aggregate formed. ?-(18-28) formed assemblies that had even a greater number of stacked sheets. The findings on these homologous synthetic assemblies help to define the specific sequence that is required to form Alzheimer's-type amyloid fibrils, thus providing an in vitro model of age-related cerebral amyloidogenesis.

1987-01-01

210

Insulin-like Growth Factor-1 (IGF-1)-induced Processing of Amyloid-? Precursor Protein (APP) and APP-like Protein 2 Is Mediated by Different Metalloproteinases*  

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?-Secretase cleavage of the amyloid precursor protein (APP) is of great interest because it prevents the formation of the Alzheimer-linked amyloid-? peptide. APP belongs to a conserved gene family including the two paralogues APP-like protein (APLP) 1 and 2. Insulin-like growth factor-1 (IGF-1) stim...

Jacobsen, Kristin T.; Adlerz, Linda; Multhaup, Gerd; Iverfeldt, Kerstin

211

The amyloid precursor protein represses expression of acetylcholinesterase in neuronal cell lines.  

UK PubMed Central (United Kingdom)

The toxic role of amyloid ? peptides in Alzheimer's disease is well documented. Their generation is via sequential ?- and ?-secretase cleavage of the membrane-bound amyloid precursor protein (APP). Other APP metabolites include the soluble ectodomains sAPP? and sAPP? and also the amyloid precursor protein intracellular domain (AICD). In this study, we examined whether APP is involved in the regulation of acetylcholinesterase (AChE), which is a key protein of the cholinergic system and has been shown to accelerate amyloid fibril formation and increase their toxicity. Overexpression of the neuronal specific isoform, APP695, in the neuronal cell lines SN56 and SH-SY5Y substantially decreased levels of AChE mRNA, protein, and catalytic activity. Although similar decreases in mRNA levels were observed of the proline-rich anchor of AChE, PRiMA, no changes were seen in mRNA levels of the related enzyme, butyryl-cholinesterase, nor of the high-affinity choline transporter. A ?-secretase inhibitor did not affect AChE transcript levels or enzyme activity in SN56 (APP695) or SH-SY5Y (APP695) cells, showing that regulation of AChE by APP does not require the generation of AICD or amyloid ? peptide. Treatment of wild-type SN56 cells with siRNA targeting APP resulted in a significant up-regulation in AChE mRNA levels. Mutagenesis studies suggest that the observed transcriptional repression of AChE is mediated by the E1 region of APP, specifically its copper-binding domain, but not the C-terminal YENTPY motif. In conclusion, AChE is regulated in two neuronal cell lines by APP in a manner independent of the generation of sAPP?, sAPP?, and AICD.

Hicks DA; Makova NZ; Gough M; Parkin ET; Nalivaeva NN; Turner AJ

2013-09-01

212

99mTc-MAMA-chrysamine G, a probe for beta-amyloid protein of Alzheimer's disease  

International Nuclear Information System (INIS)

[en] Chrysamine G (CG), an analogue of Congo red, is known to bind in vitro to the ?-amyloid protein (A? 10-43) and to homogenates of several regions of the brain of Alzheimer's disease (AD) patients. We synthesised a conjugate of 2-(acetamido)-CG with a bis-S-trityl protected monoamide-monoaminedithiol (MAMA-Tr2) tetraligand, which was efficiently deprotected and labelled with a 75% yield with technetium-99m, to obtain 99mTc-MAMA-CG. In mice, 99mTc-MAMA-CG was cleared mainly by the hepatobiliary system, resulting in a fast blood clearance. Brain uptake of 99mTc-MAMA-CG was low. Co-injection with the blood pool tracer iodine-125 human serum albumin (125I-HSA) demonstrated a brain/blood activity ratio for 99mTc-MAMA-CG that was significantly higher than that for 125I-HSA (t test for dependent samples, P99mTc-MAMA-CG to cross the blood-brain barrier. In vitro autoradiography demonstrated pronounced binding of 99mTc-MAMA-CG to ?-amyloid deposits in autopsy sections of the parietal and occipital cortex of an AD patient as compared with controls. Adding 10 ?M Congo red during incubation displaced the binding of 99mTc-MAMA-CG. Congo red staining and autoradiography identified the same lesions. 99mTc-MAMA-CG seems to bind selectively to ?-amyloid deposition in human brain parenchyma and blood vessels in vitro and thus might be a lead compound for further development of a useful tracer agent for the in vivo diagnosis of Alzheimer's disease. (orig.)

1999-01-01

213

The inverse relation of HDL anti-oxidative functionality with serum amyloid a is lost in metabolic syndrome subjects.  

UK PubMed Central (United Kingdom)

OBJECTIVE: Anti-oxidative properties of high density lipoproteins (HDL) are relevant for atheroprotection. HDL carry serum amyloid A (SAA), which may impair HDL functionality. We questioned whether HDL anti-oxidative capacity is determined by SAA. DESIGN AND METHODS: Relationships of HDL anti-oxidative capacity (% inhibition of low density lipoprotein oxidation in vitro) with SAA were determined in 54 non-diabetic subjects without metabolic syndrome (MetS) and 68 subjects with MetS (including 51 subjects with Type 2 diabetes mellitus). RESULTS: SAA levels were higher in MetS subjects, coinciding higher high sensitive C-reactive protein (hs-CRP) and lower HDL cholesterol and apolipoprotein (apo) A-I levels (P<0.001 for all). HDL anti-oxidative capacity was not different between subjects with and without MetS (P=0.76), but the HDL anti-oxidation index (HDL anti-oxidative capacity multiplied by individual HDL cholesterol concentrations), as a measure of global anti-oxidative functionality of HDL, was lower in Mets subjects (P<0.001). HDL anti-oxidative capacity was correlated inversely with SAA levels in subjects without MetS (r=-0.286, P=0.036). Notably, this relationship was independent of HDL cholesterol or apoA-I (P<0.05 for both). In contrast, no relation of HDL anti-oxidative capacity with SAA was observed in MetS subjects (r=0.032, P=0.80). The relationship of SAA with HDL anti-oxidative capacity was different in subjects with MetS compared to subjects without MetS (P=0.039 for the interaction between the presence of MetS and SAA on HDL anti-oxidative capacity) taking age and diabetes status into account. CONCLUSION: Higher SAA levels may impair HDL anti-oxidative functionality. The relationship of this physiologically relevant HDL functionality measure with circulating SAA levels is apparently disturbed in metabolic syndrome.

Dullaart RP; de Boer JF; Annema W; Tietge UJ

2013-02-01

214

Serum protein electrophoresis in spontaneous canine hyperadrenocorticalism.  

Science.gov (United States)

The serum protein concentrations of dogs with confirmed spontaneous hyperadrenocorticalism were determined by agarose gel electrophoresis before and during treatment with mitotane. In untreated animals a significant increase was detected in the mean concentration of total protein and the mean concentration and percentage of alpha-2 globulin. The mean concentration and percentage of albumin and gamma-globulin were significantly decreased. In animals on treatment the mean concentration of total proteins and the mean concentration and percentage of beta-2 globulin were significantly reduced. PMID:2466309

van den Broek, A H; Lida, J

1989-01-01

215

Correlations between serum levels of beta amyloid, cerebrospinal levels of tau and phospho tau, and delayed response tasks in young and aged cynomolgus monkeys (Macaca fascicularis)  

DEFF Research Database (Denmark)

In an attempt to explore cynomolgus monkeys as an animal model for Alzheimer's disease, the present study focused on the Alzheimer's biomarkers beta amyloid 1-42 (A?42 ) in serum, and total tau (t-tau) and phosphorylated tau (p-tau) levels in cerebrospinal fluid.

Darusman, Huda Shalahudin; Sajuthi, D

2013-01-01

216

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

Directory of Open Access Journals (Sweden)

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

Nilsen Jon; Chen Shuhua; Irwin Ronald W; Iwamoto Sean; Brinton Roberta

2006-01-01

217

Overexpression of amyloid precursor protein reduces epsilon protein kinase C levels.  

Science.gov (United States)

Alzheimer's disease (AD) is characterized by extracellular deposits of amyloid beta peptide (Abeta), a peptide that is generated upon proteolytic cleavage of amyloid precursor protein (APP). The events leading to the development of AD and their sequence are not yet fully understood. Protein kinase C (PKC) has been suggested to have a significant role in controlling neuronal degeneration and in the aberrant signal transduction taking place in AD. Several studies document a deficit in PKC levels and activity in brains of AD patients when compared with those of normal controls. Such a decrease in PKC could have serious implications since certain PKC isozymes were shown to drive the APP proteolytic cleavage into a non-amyloidogenic pathway. Reduced levels of distinct PKC isozymes could thus contribute to driving APP processing toward an amyloidogenic pathway. The direct cause for the down-regulation of PKC in AD brains is still unknown. In that respect, we tested in this study whether APP may play a role in PKC reduction. We show in three different cell lines (CHO, COS and BOSC) that overexpression of APP leads to decreased PKC levels. This decrease was found to be specific for the epsilon PKC isozyme whereas the levels of delta, alpha and conventional PKC remained unchanged. Furthermore, we observed this decrease for both active, membrane-associated and inactive, cytosolic epsilon PKC. APP-driven decrease in epsilon PKC is most likely mediated by a factor in the culture medium, since transfer of medium from cultured cells overexpressing APP to naïve, non-overexpressing cells, has also led to the selective decrease in epsilon PKC levels. Taken together, our results suggest that APP expression levels may play a role in the decrease of epsilon PKC levels in AD brains and could thus affect the responsiveness of AD brain tissues to growth factors and neurotransmitters. PMID:17321053

Liron, T; Seraya, C Bareket; Ish-Shalom, M; Souroujon, M C; Neumann, D

2007-02-22

218

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

International Nuclear Information System (INIS)

[en] 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

2009-01-01

219

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

220

Amyloid beta protein: Abeta40 inhibits Abeta42 oligomerization.  

UK PubMed Central (United Kingdom)

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.

Murray MM; Bernstein SL; Nyugen V; Condron MM; Teplow DB; Bowers MT

2009-05-01

 
 
 
 
221

Factors influencing theophylline serum protein binding.  

UK PubMed Central (United Kingdom)

We studied a number of influences on theophylline binding to serum proteins using equilibrium dialysis (37 degrees), a modified Krebs-Ringer bicarbonate buffer (pH 7.4), and 8-14C-theophylline with unlabeled theophylline (30 microgram/ml) added to sera from healthy subjects. Theophylline protein binding rose by 18.6% as pH rose from 7.0 to 7.8 (percent theophylline bound = 28.2 +/- 4.3 at pH 7.0 and 46.8 +/- 4.9 at pH 7.8, n = 5). Average theophylline binding to the proteins at 37 degrees in serum samples from 10 normal adults was 39.3 +/- 3.44%, which is 89.9% lower than the average of 48.2 +/- 3.74% for the same samples at 26 degrees. Theophylline binding was 6.1% higher with 0.1 mole/l phosphate buffer, pH 7.4, than with a modified Krebs-Ringer bicarbonate buffer, pH 7.4. Of the 19 drugs and metabolites tested for competition with theophylline for binding sites on serum proteins, 10 induced decreases in binding ranging from 6.8% in the case of furosemide to 18.3% for sodium salicylate. The latter was the only drug that induced a decrease in theophylline binding at concentrations that would be achieved in the therapy of same patients (i.e., patients on long-term salicylate therapy). All the other drugs that decreased theophylline binding did so at much greater concentrations than their usual therapeutic levels. The mean +/- SD of theophylline bound in 51 fresh serum samples from healthy adults was 48.6 +/- 10.2%; the pH of these specimens varied from 7.6 to 8.7. After adjusting pH to 7.4, theophylline binding was lowered to 37.6 +/- 4.5% and intersubject variability decreased. We recommend that the pH of serum specimens be adjusted to 7.4, or to the original pH of the blood specimen if it differs significantly from 7.4 (i.e., in acidotic or alkalotic patients). The wide range of reported values for theophylline binding to serum proteins in normal and asthmatic adults at least partly results from differences in the conditions used for the separation of free from bound drug.

Shaw LM; Fields L; Mayock R

1982-10-01

222

Automated serum protein electrophoresis by Capillarys.  

Science.gov (United States)

Capillary zone electrophoresis (CZE) of serum proteins is increasingly gaining impact in clinical laboratories. In this report, we evaluate automated capillary zone electrophoresis by Capillarys (Sebia, France). Within-run and between-run imprecision for the five electrophoretic fractions was bisalbuminemia, and alpha1-antitrypsin deficiency revealed that Capillarys was able to detect these abnormalities. Two hundred thirty eight samples were analyzed by agarose gel electrophoresis, Capillarys, capillary electrophoresis using Paragon CZE 2000 system, and immunofixation. Sample selection was based on the presence of a disturbed morphology (e.g., spike) of the protein profile or hypogammaglobulinemia on agarose gel electrophoresis and/or Capillarys. Immunofixation revealed the presence of a monoclonal protein, oligoclonal bands, polyclonal pattern, and a normal profile in, respectively, 89, 66, 19, and 64 samples. With Capillarys, Paragon, and agarose gel electrophoresis, a spike and/or disturbed morphology of the profile was found in 222, 182, and 180 samples, respectively. In these samples, immunofixation was negative in 73 (33%), 46 (25%), and 39 (22%) samples, respectively. These data indicate that Capillarys has a lower specificity than agarose gel electrophoresis and Paragon 2000. Of the 89 samples with a monoclonal protein, Capillarys, Paragon, and agarose gel electrophoresis failed to detect, respectively, three, three, and one monoclonal protein(s). Interferences by radio-opaque agents, complement degradation products, fibrinogen, and triglycerides are described. In conclusion, automated capillary zone electrophoresis with Capillarys provides for reproducible, rapid, and reliable serum electrophoresis. PMID:12812271

Bossuyt, Xavier; Lissoir, Bénédicte; Mariën, Godelieve; Maisin, Diane; Vunckx, Jozef; Blanckaert, Norbert; Wallemacq, Pierre

2003-05-01

223

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

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

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

1990-04-27

224

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

International Nuclear Information System (INIS)

[en] 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

225

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

226

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

227

Rimmed vacuoles with beta-amyloid and tau protein deposits in the muscle of children with hereditary myopathy.  

Science.gov (United States)

We investigated whether beta-amyloid and tau protein are involved in the formation of inclusion body myositis (IBM)-like inclusions found in children with rimmed vacuoles and congenitally affected muscles. We immunostained muscle biopsy specimens from four children and one 18-year-old boy with congenital myopathy containing rimmed vacuoles and IBM-like inclusions with antibodies against beta-amyloid, tau protein and ubiquitin. Focal accumulations of both beta-amyloid and phosphorylated tau coexisted with tubulofilamentous structures in all cases. Our studies demonstrate for the first time that the full morphological phenotype of IBM including beta-amyloid and tau protein deposits may also develop in children, and that congenital, probably genetic, muscle defects may lead to abnormal protein aggregation in IBM-like inclusions. PMID:16788822

Fidzia?ska, Anna; Glinka, Zofia

2006-06-21

228

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

UK PubMed Central (United Kingdom)

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 HY; Kim SD; Baek SH; Choi JH; Cho KH; Zabel BA; Bae YS

2013-03-01

229

Invariant NKT cells modulate the suppressive activity of Serum Amyloid A-differentiated IL-10-secreting neutrophils  

Science.gov (United States)

Neutrophils are the primary effector cells during inflammation, but can also control excessive inflammatory responses by secreting anti-inflammatory cytokines. However, the mechanisms modulating their plasticity remain unclear. We now show that systemic serum amyloid A-1 (SAA-1) controls the plasticity of neutrophil differentiation. SAA-1 not only induced anti-inflammatory IL-10-secreting neutrophils but also promoted invariant NKT (iNKT) cell interaction with these neutrophils, a process that limits their suppressive activity by reducing IL-10 and enhancing IL-12 production. Because SAA-1-producing melanomas promote differentiation of IL-10-secreting neutrophils, harnessing iNKT cells could be useful therapeutically by reducing the frequency of immunosuppressive neutrophils and restoring tumor specific immune responses.

De Santo, Carmela; Arscott, Ramon; Booth, Sarah; Karydis, Ioannis; Jones, Margaret; Asher, Ruth; Salio, Mariolina; Middleton, Mark; Cerundolo, Vincenzo

2010-01-01

230

THE USE OF ELECTROPHORESIS IN LABORATORY DIAGNOSTIC OF SERUM PROTEINS IN VETERINARY MEDICINE  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, we explain the need for more detailed laboratory diagnostic of serum proteins in veterinary medicine. The application of proteomic approaches over the last decade has provided new tools for clarifying the molecular aspects of physiological states, and for understanding the etiology and pathogenesis of many diseases. Proteomics performs large-scale protein analysis, describes the entire protein complement of a cell, tissue, biological fluid or organism and provides information on protein expression, localization, functions and interactions. Majority of plasmatic proteins is synthesized in hepatocytes, with albumin representing their largest quantitative part. The second major contributor is the imune system. Plasma proteins perform a nutritive function, exert colloidal osmotic pressure, and aid in the maintenance of acid-base balance. Individual proteins serve as enzymes, antibodies, coagulation factors, hormones, and transport substances. Fresh serum contains all of the plasma proteins except fibrinogen, factor V, and factor VIII. These are consumed during clot formation. The electrophoretic technique is the current standard of reference for the fractionation of the serum proteins in clinical biochemistry. Serum proteins determined by electrophoresis involves albumin, ?1, ?2, ?1, ?2 and ?-globulins. Individual blood serum proteins have different functions and their identification is used also as a diagnostic tool. Many of these proteins are the so-called acute phase proteins. For example, ?1-acid glycoprotein concentration increases during inflammation or infection, as well as concentrations of other acute phase proteins (CRP, serum amyloid A protein, ?1-antitrypsin, haptoglobin, ceruloplasmin and fibrinogen) based on increased synthesis of hepatocytes with subsequent release of these proteins in blood. Alfa1-antitrypsin, member of the superfamily of proteinase inhibitors, has a crucial effect on inactivation of neutrophil elastase and other proteases, which maintains protease–antiprotease balance. Ceruloplasmin takes part in copper metabolism and its decreased plasmatic concentration is associated with copper deficiency. Concentrations of serum proteins are influenced by many physiological (age, pregnancy, lactacion etc.) and pathological (malnutrition, renal and hepatal diseases etc.) factors. Current widespread use of electrophoresis is commensurate with its reflection of a variety of changes in serum protein patterns in disease in different species of animals.

Veronika Nagyová; Csila Tóthová; Helena Šoltésová; Mária Vargová; Oskar Nagy

2013-01-01

231

Alzheimer beta/A4-amyloid precursor protein: evidence for putative amyloidogenic fragment.  

Science.gov (United States)

Recombinant baculovirus was used to overexpress human Alzheimer beta/A4-amyloid precursor protein (APP) in Spodoptera frugiperda (Sf9) cells. Lysates of these cells were then analyzed for the presence of carboxyl-terminal fragments of APP by an immunoblotting assay using either an antibody against the APP cytoplasmic domain (rabbit anti-human 695APP645-694) or an antibody against the amino terminus of beta/A4-amyloid (rabbit anti-human 695APP586-606). Anti-human 695APP645-694 identified APP holoprotein, a 25-kDa species, and a prominent group of carboxyl-terminal fragments of 17, 16, and 14 kDa, whereas anti-human 695APP586-606 identified APP holoprotein and a single prominent low-molecular-mass protein species comigrating with the 17-kDa carboxyl-terminal fragment identified by anti-human 695APP645-694. No immunoreactive species was detected at these molecular mass positions when either antibody was used for analysis of lysates of either uninfected Sf9 cells or Sf9 cells infected with wild-type Autographa californica baculovirus. For each antibody, specific immunoreactivity was abolished by preabsorption with the corresponding peptide immunogen. The incorporation of a beta/A4-amyloid amino-terminal epitope into a 17-kDa fragment of APP suggests that, in the baculoviral overexpression system, the electrophoretic microheterogeneity of APP carboxyl-terminal fragments is due, at least in part, to alternative proteolysis of APP. If such carboxyl-terminal fragments of APP containing an intact beta/A4-amyloid domain are produced in human brain, then they may represent intermediates in the conversion of APP to deposited beta/A4-amyloid.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1345769

Gandy, S E; Bhasin, R; Ramabhadran, T V; Koo, E H; Price, D L; Goldgaber, D; Greengard, P

1992-01-01

232

Alzheimer beta/A4-amyloid precursor protein: evidence for putative amyloidogenic fragment.  

UK PubMed Central (United Kingdom)

Recombinant baculovirus was used to overexpress human Alzheimer beta/A4-amyloid precursor protein (APP) in Spodoptera frugiperda (Sf9) cells. Lysates of these cells were then analyzed for the presence of carboxyl-terminal fragments of APP by an immunoblotting assay using either an antibody against the APP cytoplasmic domain (rabbit anti-human 695APP645-694) or an antibody against the amino terminus of beta/A4-amyloid (rabbit anti-human 695APP586-606). Anti-human 695APP645-694 identified APP holoprotein, a 25-kDa species, and a prominent group of carboxyl-terminal fragments of 17, 16, and 14 kDa, whereas anti-human 695APP586-606 identified APP holoprotein and a single prominent low-molecular-mass protein species comigrating with the 17-kDa carboxyl-terminal fragment identified by anti-human 695APP645-694. No immunoreactive species was detected at these molecular mass positions when either antibody was used for analysis of lysates of either uninfected Sf9 cells or Sf9 cells infected with wild-type Autographa californica baculovirus. For each antibody, specific immunoreactivity was abolished by preabsorption with the corresponding peptide immunogen. The incorporation of a beta/A4-amyloid amino-terminal epitope into a 17-kDa fragment of APP suggests that, in the baculoviral overexpression system, the electrophoretic microheterogeneity of APP carboxyl-terminal fragments is due, at least in part, to alternative proteolysis of APP. If such carboxyl-terminal fragments of APP containing an intact beta/A4-amyloid domain are produced in human brain, then they may represent intermediates in the conversion of APP to deposited beta/A4-amyloid.(ABSTRACT TRUNCATED AT 250 WORDS)

Gandy SE; Bhasin R; Ramabhadran TV; Koo EH; Price DL; Goldgaber D; Greengard P

1992-01-01

233

Automated serum protein electrophoresis by Capillarys.  

UK PubMed Central (United Kingdom)

Capillary zone electrophoresis (CZE) of serum proteins is increasingly gaining impact in clinical laboratories. In this report, we evaluate automated capillary zone electrophoresis by Capillarys (Sebia, France). Within-run and between-run imprecision for the five electrophoretic fractions was <2% and <6%, respectively. Data obtained with Capillarys correlated with results obtained with agarose gel electrophoresis and Paragon CZE 2000 (Beckman Coulter, USA). Analysis of serum obtained from patients with inflammation, nephrotic syndrome, bisalbuminemia, and alpha1-antitrypsin deficiency revealed that Capillarys was able to detect these abnormalities. Two hundred thirty eight samples were analyzed by agarose gel electrophoresis, Capillarys, capillary electrophoresis using Paragon CZE 2000 system, and immunofixation. Sample selection was based on the presence of a disturbed morphology (e.g., spike) of the protein profile or hypogammaglobulinemia on agarose gel electrophoresis and/or Capillarys. Immunofixation revealed the presence of a monoclonal protein, oligoclonal bands, polyclonal pattern, and a normal profile in, respectively, 89, 66, 19, and 64 samples. With Capillarys, Paragon, and agarose gel electrophoresis, a spike and/or disturbed morphology of the profile was found in 222, 182, and 180 samples, respectively. In these samples, immunofixation was negative in 73 (33%), 46 (25%), and 39 (22%) samples, respectively. These data indicate that Capillarys has a lower specificity than agarose gel electrophoresis and Paragon 2000. Of the 89 samples with a monoclonal protein, Capillarys, Paragon, and agarose gel electrophoresis failed to detect, respectively, three, three, and one monoclonal protein(s). Interferences by radio-opaque agents, complement degradation products, fibrinogen, and triglycerides are described. In conclusion, automated capillary zone electrophoresis with Capillarys provides for reproducible, rapid, and reliable serum electrophoresis.

Bossuyt X; Lissoir B; Mariën G; Maisin D; Vunckx J; Blanckaert N; Wallemacq P

2003-05-01

234

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2005-12-01

235

Mechanism for retardation of amyloid fibril formation by sugars in V?6 protein.  

UK PubMed Central (United Kingdom)

Sugars, which function as osmolytes within cells, retard the amyloid fibril formation of the amyloidosis peptides and proteins. To examine the mechanism of this retardation in detail, we analyzed the effect of sugars (trehalose, sucrose, and glucose) on the polypeptide chains in 3Hmut Wil, which is formed by the mutation of three His residues in Wil mutant as a cause of amyloid light-chain (AL) amyloidosis, at pH 2, a pH condition under which 3Hmut Wil was almost denatured. Sugars caused the folding of 3Hmut Wil so that its polypeptide chains adopted a native-like rather than a denatured conformation, as suggested by tryptophan fluorescence, CD spectroscopy, and heteronuclear NMR. Furthermore, these sugars promoted the folding to a native-like conformation according to the effect of preferential hydration rather than direct interaction. However, the type of sugar had no effect on the elongation of amyloid fibrils. Therefore, it was concluded that sugar affected the thermodynamic stability of 3Hmut Wil but not the elongation of amyloid fibrils.

Abe M; Abe Y; Ohkuri T; Mishima T; Monji A; Kanba S; Ueda T

2013-04-01

236

Brain amyloid ? protein and memory disruption in Alzheimer’s disease  

Directory of Open Access Journals (Sweden)

Full Text Available Weiming XiaCenter for Neurologic Diseases, Department of Neurology, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USAAbstract: The development of amyloid-containing neuritic plaques is an invariable characteristic of Alzheimer’s diseases (AD). The conversion from monomeric amyloid ? protein (A?) to oligomeric A? and finally neuritic plaques is highly dynamic. The specific Aß species that is correlated with disease severity remains to be discovered. Oligomeric A? has been detected in cultured cells, rodent and human brains, as well as human cerebrospinal fluid. Synthetic, cell, and brain derived A? oligomers have been found to inhibit hippocampal long-term potentiation (LTP) and this effect can be suppressed by the blockage of A? oligomer formation. A large body of evidence suggests that A? oligomers inhibit N-methyl-D-aspartate receptor dependent LTP; additional receptors have also been found to elicit downstream pathways upon binding to A? oligomers. Amyloid antibodies and small molecular compounds that reduce brain A? levels and block A? oligomer formation are capable of reversing synaptic dysfunction and these approaches hold a promising therapeutic potential to rescue memory disruption.Keywords: Alzheimer, amyloid, oligomer, long-term potentiation, NMDA

Weiming Xia

2010-01-01

237

Nicotine promotes survival of cells expressing amyloid precursor protein and presenilin: implication for Alzheimer's disease.  

UK PubMed Central (United Kingdom)

Amyloid-? protein (A?) accumulation is one of the major hallmarks of Alzheimer's disease (AD) and plays a crucial role in its pathogenesis. Cellular models whereby amyloid precursor protein (APP) is highly expressed are commonly used to test the efficacy of novel neuroprotective compounds. In addition to A?, it is known that mutation in the protein presenilin contributes to early onset AD. Recently, a cellular neuroblastoma model where both APP and presenilin are expressed has become available. Since protective effects of nicotine against various neurotoxins have been observed, this study was designed to determine whether nicotine would also protect against cellular damage induced by APP or APP and presenilin. Wild type neuroblastoma (N2a) cell line, and those transfected with amyloid precursor protein (APP), and the combination of APP and presenilin were pretreated with various concentrations of nicotine and the survivability of the cells were determined by MTT assay. Nicotine dose dependently provided protection against cellular loss in all cell lines, with highest protection in the double transfected (44%) followed by single transfected (30%), and wild type (21%). The effects of nicotine in turn were blocked by mecamylamine, a non-selective nicotinic antagonist. These results suggest differential sensitivity of cell lines representing AD pathology to the protective effects of nicotine and provide further support of therapeutic potential of nicotinic agonists in at least a subtype of AD patients.

Brown D; Ramlochansingh C; Manaye KF; Tizabi Y

2013-02-01

238

Nicotine promotes survival of cells expressing amyloid precursor protein and presenilin: implication for Alzheimer's disease.  

Science.gov (United States)

Amyloid-? protein (A?) accumulation is one of the major hallmarks of Alzheimer's disease (AD) and plays a crucial role in its pathogenesis. Cellular models whereby amyloid precursor protein (APP) is highly expressed are commonly used to test the efficacy of novel neuroprotective compounds. In addition to A?, it is known that mutation in the protein presenilin contributes to early onset AD. Recently, a cellular neuroblastoma model where both APP and presenilin are expressed has become available. Since protective effects of nicotine against various neurotoxins have been observed, this study was designed to determine whether nicotine would also protect against cellular damage induced by APP or APP and presenilin. Wild type neuroblastoma (N2a) cell line, and those transfected with amyloid precursor protein (APP), and the combination of APP and presenilin were pretreated with various concentrations of nicotine and the survivability of the cells were determined by MTT assay. Nicotine dose dependently provided protection against cellular loss in all cell lines, with highest protection in the double transfected (44%) followed by single transfected (30%), and wild type (21%). The effects of nicotine in turn were blocked by mecamylamine, a non-selective nicotinic antagonist. These results suggest differential sensitivity of cell lines representing AD pathology to the protective effects of nicotine and provide further support of therapeutic potential of nicotinic agonists in at least a subtype of AD patients. PMID:23313596

Brown, Dwayne; Ramlochansingh, Carlana; Manaye, Kebreten F; Tizabi, Yousef

2013-01-08

239

Relationship between monoclonal gammopathy and cardiac amyloid type.  

UK PubMed Central (United Kingdom)

BACKGROUND: Proper identification of cardiac amyloid type is essential for patient management, and has historically relied upon immunohistochemical- or immunofluorescence-based methods, often correlated with serum and urine protein electrophoresis (SPEP and UPEP) with immunofixation electrophoresis (IFE), and/or free light chain immunoassay (FLC). The recent implementation of mass spectrometry-based proteomic analysis for clinical amyloid typing allows us to determine the validity of these tests to predict amyloid type. Validity of SPEP/UPEP/IFE and FLC assays in cardiac amyloid prediction was examined. METHODS: Retrospective analysis of two tertiary care populations (n=143, 2001-2010), of cardiac biopsy-proven amyloidosis, was performed. RESULTS: Amyloid of transthyretin (ATTR) type was found in 81 (57%) of 143 patients and immunoglobulin light chain amyloid was found in the remaining 62 (43%). SPEP/UPEP/IFE detected a monoclonal gammopathy in 76 individuals, 56 with AL and 20 with ATTR amyloid and was overall a poor predictor of AL amyloid in this patient population: specificity (75%; 95% CI, 65-83%) and positive predictive value (PPV 74%; 95% CI, 63-82%). The FLC assay detected an abnormal kappa/lambda ratio in 61 patients, 53 with AL and 8 with ATTR amyloid and was a better predictor of AL amyloid type in this patient population: specificity (90%, 95% CI, 82-95%) and PPV (87%, 95% CI, 76-93%). CONCLUSIONS: ATTR was the predominant amyloid type in this large cohort of endomyocardial biopsies characterized by mass spectrometry. Although FLC performs better than SPEP/UPEP/IFE, the performance of blood and urine studies for monoclonal proteins are not adequate to classify amyloid type. SUMMARY: This large-scale retrospective analysis of cardiac amyloidosis shows that blood and urine monoclonal protein studies are not, by themselves, robust predictors of cardiac amyloid type in patients undergoing endomyocardial biopsy.

Maleszewski JJ; Murray DL; Dispenzieri A; Grogan M; Pereira NL; Jenkins SM; Judge DP; Caturegli P; Vrana JA; Theis JD; Dogan A; Halushka MK

2013-05-01

240

Bioluminescence imaging reveals inhibition of tumor cell proliferation by Alzheimer's amyloid ? protein  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Cancer and Alzheimer's disease (AD) are two seemingly distinct diseases and rarely occur simultaneously in patients. To explore molecular determinants differentiating pathogenic routes towards AD or cancer, we investigate the role of amyloid ? protein (A?) on multiple tumor cell lines that are stably expressing luciferase (human glioblastoma U87; human breast adenocarcinoma MDA-MB231; and mouse melanoma B16F). Results Quantification of the photons emitted from the MDA-MB231 or B16F cells revealed a significant inhibition of cell proliferation by the conditioning media (CM) derived from amyloid precursor protein (APP) over-expressing cells. The inhibition of U87 cells was observed only after the media was conditioned for longer than 2 days with APP over-expressing cells. Conclusion Our results suggest that A? plays an inhibitory role in tumor cell proliferation; this effect could depend on the type of tumor cells and amount of A?.

Zhao Hong; Zhu Jinmin; Cui Kemi; Xu Xiaoyin; O'Brien Megan; Wong Kelvin K; Kesari Santosh; Xia Weiming; Wong Stephen TC

2009-01-01

 
 
 
 
241

Novel G?S-protein signaling associated with membrane-tethered amyloid precursor protein intracellular domain.  

UK PubMed Central (United Kingdom)

Numerous physiological functions, including a role as a cell surface receptor, have been ascribed to Alzheimer's disease-associated amyloid precursor protein (APP). However, detailed analysis of intracellular signaling mediated by APP in neurons has been lacking. Here, we characterized intrinsic signaling associated with membrane-bound APP C-terminal fragments, which are generated following APP ectodomain release by ?- or ?-secretase cleavage. We found that accumulation of APP C-terminal fragments or expression of membrane-tethered APP intracellular domain results in adenylate cyclase-dependent activation of PKA (protein kinase A) and inhibition of GSK3? signaling cascades, and enhancement of axodendritic arborization in rat immortalized hippocampal neurons, mouse primary cortical neurons, and mouse neuroblastoma. We discovered an interaction between BBXXB motif of APP intracellular domain and the heterotrimeric G-protein subunit G?(S), and demonstrate that G?(S) coupling to adenylate cyclase mediates membrane-tethered APP intracellular domain-induced neurite outgrowth. Our study provides clear evidence that APP intracellular domain can have a nontranscriptional role in regulating neurite outgrowth through its membrane association. The novel functional coupling of membrane-bound APP C-terminal fragments with G?(S) signaling identified in this study could impact several brain functions such as synaptic plasticity and memory formation.

Deyts C; Vetrivel KS; Das S; Shepherd YM; Dupré DJ; Thinakaran G; Parent AT

2012-02-01

242

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

UK PubMed Central (United Kingdom)

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.

Wei J; Guo M; Ji H; Qin Q

2013-01-01

243

Caspase activation increases beta-amyloid generation independently of caspase cleavage of the beta-amyloid precursor protein (APP).  

UK PubMed Central (United Kingdom)

The amyloid precursor protein (APP) undergoes "alternative" proteolysis mediated by caspases. Three major caspase recognition sites have been identified in the APP, i.e. one at the C terminus (Asp720) and two at the N terminus (Asp197 and Asp219). Caspase cleavage at Asp720 has been suggested as leading to increased production of Abeta. Thus, we set out to determine which putative caspase sites in APP, if any, are cleaved in Chinese hamster ovary cell lines concurrently with the increased Abeta production that occurs during apoptosis. We found that cleavage at Asp720 occurred concurrently with caspase 3 activation and the increased production of total secreted Abeta and Abeta1-42 in association with staurosporine- and etoposide-induced apoptosis. To investigate the contribution of caspase cleavage of APP to Abeta generation, we expressed an APP mutant truncated at Asp720 that mimics APP caspase cleavage at the C-terminal site. This did not increase Abeta generation but, in contrast, dramatically decreased Abeta production in Chinese hamster ovary cells. Furthermore, the ablation of caspase-dependent cleavage at Asp720, Asp197, and Asp219 (by site-directed mutagenesis) did not prevent enhanced Abeta production following etoposide-induced apoptosis. These findings indicate that the enhanced Abeta generation associated with apoptosis does not require cleavage of APP at its C-terminal (Asp720) and/or N-terminal caspase sites.

Tesco G; Koh YH; Tanzi RE

2003-11-01

244

Truncated carboxyl-terminal fragments of beta-amyloid precursor protein are processed to amyloid beta-proteins 40 and 42.  

Science.gov (United States)

We previously showed that beta-amyloid precursor protein (APP) is cleaved not only in the middle of the membrane (gamma-cleavage) but also at novel cleavage sites close to the membrane/cytoplasmic boundary (epsilon-cleavage), releasing APP intracellular domains (AICDs) 49-99 and 50-99. To learn more about the relationship between gamma- and epsilon-cleavage, C-terminally truncated carboxyl-terminal fragments (CTFs) of APP, especially CTFs1-48 and 1-49 (the postulated products that are generated by epsilon-cleavage), were transiently expressed in CHO cells. Most importantly, the cells expressing CTF1-49 secreted predominantly amyloid beta-protein (Abeta) 40, while those expressing CTF1-48 secreted preferentially Abeta42. This supports our assumption that epsilon-cleavage precedes Alphabeta production and that preceding epsilon-cleavage determines the preference for the final Abeta species. The gamma-secretase inhibitors, L-685,458 and DAPT, suppressed Abeta production from CTF1-49. Regarding Abeta production from CTF1-48, L-685,458 suppressed it, but DAPT failed to do so. A dominant negative mutant of presenilin 1 suppressed the production of Abeta40 and 42 from both CTFs1-48 and 1-49. These data should shed significant light into the mechanism of Abeta production. PMID:15491160

Funamoto, Satoru; Morishima-Kawashima, Maho; Tanimura, Yu; Hirotani, Naoko; Saido, Takaomi C; Ihara, Yasuo

2004-10-26

245

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

UK PubMed Central (United Kingdom)

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

Pan X; Gong N; Zhao J; Yu Z; Gu F; Chen J; Sun X; Zhao L; Yu M; Xu Z; Dong W; Qin Y; Fei G; Zhong C; Xu TL

2010-05-01

246

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

Science.gov (United States)

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

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

2010-04-12

247

?-secretase cleavage of the fly amyloid precursor protein is required for glial survival.  

Science.gov (United States)

?-secretase (or BACE1) is the key enzyme in the production of ?-amyloid (A?), which accumulates in the senile plaques characteristic for Alzheimer's disease. Consequently, the lack of BACE1 prevents ?-processing of the amyloid precursor protein and A? production, which made it a promising target for drug development. However, the loss of BACE1 is also detrimental, leading to myelination defects and altered neuronal activity, functions that have been associated with the cleavage of Neuregulin and a voltage-gated sodium channel subunit. Here we show that the Drosophila ortholog of BACE, dBACE, is required for glial survival. Cell-specific knockdown experiments reveal that this is a non-cell autonomous function, as a knockdown of dBACE in photoreceptor neurons leads to progressive degeneration of glia in their target zone, the lamina. Interestingly, this phenotype is suppressed by the loss of the fly amyloid precursor protein (APPL), whereas a secretion-deficient form of APPL enhances the degeneration. This shows that full-length APPL in neurons promotes the death of neighboring glial cells and that ?-processing of APPL is needed to prevent glial death. These results therefore not only demonstrate a novel function for an APP protein in glia, but they also show this function specifically requires regulation by ?-cleavage. PMID:23152602

Bolkan, Bonnie J; Triphan, Tilman; Kretzschmar, Doris

2012-11-14

248

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

249

Feasibility of Predicting MCI/AD Using Neuropsychological Tests and Serum ?-Amyloid  

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We examined the usefulness of brief neuropsychological tests and serum A? as a predictive test for detecting MCI/AD in older adults. Serum A? levels were measured from 208 subjects who were cognitively normal at enrollment and blood draw. Twenty-eight of the subjects subsequently developed MCI (n = ...

Luis, Cheryl A.; Abdullah, Laila; Ait-Ghezala, Ghania; Mouzon, Benoit; Keegan, Andrew P.; Crawford, Fiona; Mullan, Michael

250

Evaluation of an automated assay based on monoclonal anti-human serum amyloid A (SAA) antibodies for measurement of canine, feline, and equine SAA  

DEFF Research Database (Denmark)

Major acute phase proteins (APPs) have proven diagnostically useful in dogs, cats and horses with routine use facilitated by commercially available automated heterologous assays. An automated assay applicable across all three species would highly facilitate further dissemination of routine use, and the aim of this study was to validate an automated latex agglutination turbidimetric immunoassay based on monoclonal anti-human serum amyloid A (SAA) antibodies for measurement of canine, feline and equine SAA. Serum samples from 60 dogs, 40 cats and 40 horses were included. Intra- and inter-assay imprecision, linearity and detection limit (DL) were determined to assess analytical performance. To assess clinical performance, equine and feline SAA measurements were compared with parallel measurements using a previously validated automated SAA assay in a method comparison setting, and by assessing overlap performance of canine SAA in healthy dogs and diseased dogs with and without systemic inflammation. Intra- and inter-assay CVs ranged between 1.9-4.6% and between 3.0-14.5%, respectively. Acceptable linearity within a clinically relevant range of SAA concentrations was observed for all three species. The DL was 1.06mg/L. Method comparison revealed acceptable agreement of the two assays measuring feline and equine SAA, and the overlap performance of canine SAA was acceptable. The tested assay measured SAA in canine, feline and equine serum with analytical and overlap performance acceptable for clinical purposes so improving practical aspects of clinical APP application. The monoclonal nature of the antibodies suggests strong, long-term inter-batch performance stability.

Christensen, Michelle BrØnniche; Jacobsen, S

2012-01-01

251

Electrohydrodynamic atomization of protein (bovine serum albumin).  

UK PubMed Central (United Kingdom)

Bovine serum albumin (BSA) was chosen as a model protein. Three solutions of different concentrations of 5, 20 and 50 mg/ml were prepared, characterised and subjected to electrohydrodynamic atomization (EHDA). The 5 and 20 mg/ml solutions were atomized successfully and mode selection (M-S) maps were drawn for both concentrations to find out regions of stable cone-jet mode atomizaton. Droplet relics of these two solutions were investigated by electron microscopy. Samples were investigated by UV spectroscopy and circular dichroism (CD) spectroscopy before and after electrohydrodynamic atomization. We conclude that, particularly at the higher concentration of protein, EHDA does not result in significant structural change of BSA, and therefore is a processing route that can be considered for encapsulating drugs in proteins.

Pareta R; Brindley A; Edirisinghe MJ; Jayasinghe SN; Luklinska ZB

2005-10-01

252

Electrohydrodynamic atomization of protein (bovine serum albumin).  

Science.gov (United States)

Bovine serum albumin (BSA) was chosen as a model protein. Three solutions of different concentrations of 5, 20 and 50 mg/ml were prepared, characterised and subjected to electrohydrodynamic atomization (EHDA). The 5 and 20 mg/ml solutions were atomized successfully and mode selection (M-S) maps were drawn for both concentrations to find out regions of stable cone-jet mode atomizaton. Droplet relics of these two solutions were investigated by electron microscopy. Samples were investigated by UV spectroscopy and circular dichroism (CD) spectroscopy before and after electrohydrodynamic atomization. We conclude that, particularly at the higher concentration of protein, EHDA does not result in significant structural change of BSA, and therefore is a processing route that can be considered for encapsulating drugs in proteins. PMID:16167100

Pareta, R; Brindley, A; Edirisinghe, M J; Jayasinghe, S N; Luklinska, Z B

2005-10-01

253

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

UK PubMed Central (United Kingdom)

Studies suggest that inflammation impairs reverse cholesterol transport (RCT). We investigated whether serum amyloid A (SAA) contributes to this impairment using an established macrophage-to-feces RCT model. Wild-type (WT) mice and mice deficient in SAA1.1 and SAA2.1 (SAAKO) were injected intraperitoneally with (3)H-cholesterol-labeled J774 macrophages 4?hr after administration of LPS or buffered saline. (3)H-cholesterol in plasma 4?hr after macrophage injection was significantly reduced in both WT and SAAKO mice injected with LPS, but this was not associated with a reduced capacity of serum from LPS-injected mice to promote macrophage cholesterol efflux in vitro. Hepatic accumulation of (3)H-cholesterol was unaltered in either WT or SAAKO mice by LPS treatment. Radioactivity present in bile and feces of LPS-injected WT mice 24?hr after macrophage injection was reduced by 36% (P < 0.05) and 80% (P < 0.001), respectively. In contrast, in SAAKO mice, LPS did not significantly reduce macrophage-derived (3)H-cholesterol in bile, and fecal excretion was reduced by only 45% (P < 0.05). Injection of cholesterol-loaded allogeneic J774 cells, but not syngeneic bone-marrow-derived macrophages, transiently induced SAA in C57BL/6 mice. Our study confirms reports that acute inflammation impairs steps in the RCT pathway and establishes that SAA plays only a minor role in this impairment.

de Beer MC; Wroblewski JM; Noffsinger VP; Ji A; Meyer JM; van der Westhuyzen DR; de Beer FC; Webb NR

2013-01-01

254

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

Directory of Open Access Journals (Sweden)

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; Melissa A. Moss; Christa N. Hestekin

2012-01-01

255

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2006-01-01

256

?-Amyloid Precursor Protein: Function in Stem Cell Development and Alzheimer's Disease Brain.  

UK PubMed Central (United Kingdom)

Stem cell therapy may be a suitable approach for the treatment of many neurodegenerative diseases. However, one major impediment to the development of successful cell-based therapies is our limited understanding of the mechanisms that instruct neural stem cell behaviour, such as proliferation and cell fate specification. The ?-amyloid precursor protein (APP) of Alzheimer's disease (AD) may play an important role in neural stem cell proliferation and differentiation. Our recent work shows that in vitro, APP stimulates neural stem or progenitor cell proliferation and neuronal differentiation. The effect on proliferation is mediated by an autocrine factor that we have identified as cystatin C. As cystatin C expression is also reported to inhibit the development of amyloid pathology in APP transgenic mice, our finding has implications for the possible use of cystatin C for the therapy of AD. © 2013 S. Karger AG, Basel.

Small DH; Hu Y; Bolós M; Dawkins E; Foa L; Young KM

2013-08-01

257

Introduction of yeast artificial chromosomes containing mutant human amyloid precursor protein genes into transgenic mice  

Energy Technology Data Exchange (ETDEWEB)

Several hypothetical mechanisms have been proposed for the generation and deposition of the amyloid beta (A{beta}) peptide in Alzheimer`s disease (AD). These include overexpression of the amyloid precursor protein (APP) gene, as suggested by Down Syndrome (DS, trisomy 21), and mutation of APP, as suggested by mutations associated with the presence of disease/amyloid deposition in some cases of familial AD (FAD). Although numerous in vitro studies have lead to certain insights into the molecular basis for amyloid deposition, the mechanisms(s) of amyloidogenesis in vivo remains poorly defined. To examine the effect of FAD mutations on amyloidogenesis in an animal model, we have focused on producing APP YAC transgenic mice containing the human APP gene with FAD mutations. These APP YAC transgenics are being produced by introduction of a 650 kb APP YAC through lipid-mediated transfection of ES cells. This strategy has two principal advantages: the APP genomic sequences contain transcriptional regulatory elements required for proper spatial and temporal expression and contain appropriate splice donor and acceptor sites needed to generate the entire spectrum of alternatively spliced APP transcripts. As a first step, we cloned the genomic regions surrounding APP exons 16 and 17 from an APP YAC sublibrary. Both the Swedish and the 717 mutations were then introduced into exons 16 and 17, respectively, by PCR mutagenesis, and subsequently transferred into the 650 kb APP YAC by a two step gene replacement in yeast. The mutant YACs have been introduced into ES cells, and we have determined that these cells are expressing human mutant APP mRNA and protein. These cells are being used to generate transgenic mice. This paradigm should provide the appropriate test of whether a mutant APP gene is capable of producing AD-like pathology in a mouse model.

Call, L.M.; Lamb, B.T.; Boese, K.F. [Johns Hopkins Univ. School of Medicine, Baltimore, MD (United States)] [and others

1994-09-01

258

The mechanism of S100 #beta# expression induced by #beta#-amyloid protein in rat hippocampus  

UK PubMed Central (United Kingdom)

To explore th emechnanism and effects of #beta#-amyloid protein (A#beta#) on S100#beta# expression. Different intervals after bilateral stereotaxis injection of A#beta#_(25-35) and interleukin-1 receptor antagonist (IL-1ra) into the CA1 region of the rat hippocampus, learning and memory, amyloid eposition, and the S100#beta# expression in hippocampal CA1 region wer analyzed by means of behaior test, Congo red taining, and immunohistochemistry combined with stereologic analysis. Twenty-one days after A#beta# injection. the learning and memory abilitites of the rats were significnatly decreased. The amyloid deposition was detected in the hippocampus, the glial fibrillary acidica protein (GFAP) positive astrocytes were found surrounding amyloid depostivon. The number of S100#betA positive cells in experiment groups was significnalty increased at all time ponts. The averge area of S100#beta# positive cels was increased significnatly only 21 days after A#beta#injectsion. The number of S100#betA# positive cells was significantly decreasted at 3 and 7 days after IL-1ra injection, and still increased compared with that of control group at each time point. Instrahippocapal injection of A#beta#_(25-35) can cause similar pathologic changes of Alzheimer^s disease (AD), and decrease the learning and memory abilites of rats. Our eperiment might provide a useful animal model for study of AD. A#beta#_(25-35) is capable of up-regulating S100#beta# expression. Cell number increases at the exarlier stage of experiment, and cells area increase significantly at end stage. The injection of IL-1ra can attenuate effect of A#beta# on S100#beta#expression by blocking eh effects of IL-1 which is relased from activated microglia induced by A#beta#, on activating astrocytes.

Yang Jie; Liu Yong; Qian Yihua; Hu Haitao; Qiu Fen; Guo Shiping

2004-01-01

259

Altered Levels of Amyloid Precursor Protein Intracellular Domain-interacting Proteins in Alzheimer Disease.  

UK PubMed Central (United Kingdom)

BACKGROUND:: The amyloid precursor protein intracellular domain (AICD) is an intrinsically unstructured molecule with functional promiscuity that plays an important role in determining the fate of the neurons during its degeneration. Its association with Alzheimer disease (AD) played a key role in propelling scientists to choose AICD as a major molecule of interest. Although several studies have been conducted elucidating AICD's participation in inducing neurodegenerative outcomes in AD condition, much remains to be deciphered regarding the linkage of AICD with cellular pathways in the AD scenario. RESULTS:: In the present study, we have pulled down interactors of nonphosphorylated AICD from the cerebrospinal fluid of AD subjects, identified them by matrix assisted laser desorption ionization mass spectrometry, and subsequently studied the differential expression of these interactors in AD and control cases by 2-dimensional difference gel electrophoresis. The study has yielded some AICD-interactors that are differentially expressed in the AD cases and are involved in diverse cellular functions. CONCLUSIONS:: This proteomic-based approach highlights the first step in finding the possible cellular pathways engaged in AD pathophysiology on the basis of interaction of one or more of their members with AICD.

Chakrabarti A; Chatterjee A; Sengupta MB; Chattopadhyay P; Mukhopadhyay D

2013-09-01

260

A novel acute phase reactant, serum amyloid A-like 1, from Oplegnathus fasciatus: genomic and molecular characterization and transcriptional expression analysis.  

UK PubMed Central (United Kingdom)

Acute phase response is a significant component of innate immunity, playing a vital role in the signaling processes and elimination of invading pathogens. Acute phase proteins are synthesized in liver and secreted into the blood for transportation to an infection site, where the defense function is exerted. Serum amyloid A (SAA) and C-reactive proteins are the major positive acute phase proteins. In this study, we have identified and characterized a novel SAA related gene from rock bream (Oplegnathus fasciatus), designated OfSAAL1. Genomic characterization revealed the presence of 13 exons and 12 introns, similar to SAAL1 in zebrafish. Multiple protein sequence alignment revealed high conservation with other SAAL1 homologues. Phylogenetic analysis showed that OfSAAL1 clustered with another fish homologue, and pairwise alignment revealed highest identity and similarity at the amino acid level with zebrafish SAAL1. Promoter region analysis revealed the presence of immunologically significant transcription factor binding sites. Tissue distribution profiling to indicate physiological relevance showed the highest levels occur in blood, followed by liver, suggesting a positive immune role in rock bream. Transcriptional analysis by reverse transcription polymerase chain reaction to understand OfSAAL1 responsiveness to immune challenge with poly I:C, Edwardsiella tarda, Streptococcus iniae and rock bream iridovirus, revealed a significant level of elevation from 12h to 48 h post-infection in blood, spleen, head kidney, and liver. To our knowledge, OfSAAL1 is the first characterized SAAL1 homologue from teleosts. We anticipate that its identification will prove inspiring for further studies of SAAL1 homologues as biomarkers of the acute phase response.

Saranya Revathy K; Umasuthan N; Whang I; Lee Y; Lee S; Oh MJ; Jung SJ; Choi CY; Park CJ; Park HC; Lee J

2012-06-01

 
 
 
 
261

A novel acute phase reactant, serum amyloid A-like 1, from Oplegnathus fasciatus: genomic and molecular characterization and transcriptional expression analysis.  

Science.gov (United States)

Acute phase response is a significant component of innate immunity, playing a vital role in the signaling processes and elimination of invading pathogens. Acute phase proteins are synthesized in liver and secreted into the blood for transportation to an infection site, where the defense function is exerted. Serum amyloid A (SAA) and C-reactive proteins are the major positive acute phase proteins. In this study, we have identified and characterized a novel SAA related gene from rock bream (Oplegnathus fasciatus), designated OfSAAL1. Genomic characterization revealed the presence of 13 exons and 12 introns, similar to SAAL1 in zebrafish. Multiple protein sequence alignment revealed high conservation with other SAAL1 homologues. Phylogenetic analysis showed that OfSAAL1 clustered with another fish homologue, and pairwise alignment revealed highest identity and similarity at the amino acid level with zebrafish SAAL1. Promoter region analysis revealed the presence of immunologically significant transcription factor binding sites. Tissue distribution profiling to indicate physiological relevance showed the highest levels occur in blood, followed by liver, suggesting a positive immune role in rock bream. Transcriptional analysis by reverse transcription polymerase chain reaction to understand OfSAAL1 responsiveness to immune challenge with poly I:C, Edwardsiella tarda, Streptococcus iniae and rock bream iridovirus, revealed a significant level of elevation from 12h to 48 h post-infection in blood, spleen, head kidney, and liver. To our knowledge, OfSAAL1 is the first characterized SAAL1 homologue from teleosts. We anticipate that its identification will prove inspiring for further studies of SAAL1 homologues as biomarkers of the acute phase response. PMID:22504166

Saranya Revathy, Kasthuri; Umasuthan, Navaneethaiyer; Whang, Ilson; Lee, Youngdeuk; Lee, Sukkyoung; Oh, Myung-Joo; Jung, Sung-Ju; Choi, Cheol Young; Park, Choul-Ji; Park, Hae-Chul; Lee, Jehee

2012-04-12

262

Uncoupling of M1 muscarinic receptor/G-protein interaction by amyloid ?(1-42).  

UK PubMed Central (United Kingdom)

The overproduction of ?-amyloid (A?) fragments in transgenic APPswe/PS1dE9 mice results in formation of amyloid deposits in the cerebral cortex and hippocampus starting around four months of age and leading to cognitive impairment much later. We have previously found an age and transgene-dependent weakening of muscarinic receptor-mediated transmission that was not present in young (6-10-week-old) animals but preceded both amyloid deposits and cognitive deficits. Now we investigated immediate and prolonged in vitro effects of non-aggregated A?(1-42) on coupling of individual muscarinic receptor subtypes expressed in CHO (Chinese hamster ovary) cells and their underlying mechanisms. Immediate application of 1 ?M A?(1-42) had no effect on the binding of the muscarinic antagonist N-methylscopolamine or the agonist carbachol. In contrast, 4-day treatment of CHO cells expressing the M1 muscarinic receptor with 100 nM A?(1-42) significantly changed the binding characteristics of the muscarinic agonist carbachol and reduced the extent of the M1 receptor-stimulated breakdown of phosphatidylinositol while it did not demonstrate overt toxic effects. The treatment had no influence on the expression of either G-proteins or muscarinic receptors. In concert, we found no change in the gene expression of muscarinic receptor subtypes and gene or protein expression of the G(s), G(q/11), and G(i/o) G-proteins in the cerebral cortex of young adult APPswe/PS1dE9 mice that demonstrate high concentrations of soluble A?(1-42) and impaired muscarinic receptor-mediated G-protein activation. Our results provide strong evidence that the initial injurious effects of A?(1-42) on M1 muscarinic receptor-mediated transmissionis is due to compromised coupling of the receptor with G(q/11) G-protein.

Janí?ková H; Rudajev V; Zim?ík P; Jakubík J; Tanila H; El-Fakahany EE; Doležal V

2013-04-01

263

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1988-03-01

264

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

International Nuclear Information System (INIS)

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

1988-01-01

265

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.  

Science.gov (United States)

Inhibition of AB(5)-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 mediating formation of face-to-face SAP-AB(5) complexes, block receptor recognition sites and redirect toxins to the spleen and liver for degradation. Direct correlation between solid-phase activity and protective dose of PolyBAITs both in the cytotoxicity assay and in vivo indicate that the mechanism of protection from intoxication is inhibition of toxin binding to the host cell membrane. The polymeric scaffold influences the activity not only by clustering active binding fragments but also by sterically interfering with the supramolecular complex assembly. Thus, inhibitors based on N-(2-hydroxypropyl) methacrylamide (HPMA) show significantly lower activity than polyacrylamide-based analogs. The detrimental steric effect can partially be alleviated by extending the length of the spacer, which separates pendant ligand from the backbone, as well as extending the spacer, which spans the distance between binding moieties within each heterobifunctional ligand. Herein we report that polymer size and payload of the active ligand had moderate effects on the inhibitor's activity. PMID:22069757

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

2011-08-25

266

From synaptic spines to nuclear signaling: nuclear and synaptic actions of the amyloid precursor protein.  

UK PubMed Central (United Kingdom)

Despite intensive studies of the secretase-mediated processing of the amyloid precursor protein (APP) to form the amyloid ?-peptide (A?), in relation to Alzheimer's disease (AD), no new therapeutic agents have reached the clinics based on reducing A? levels through the use of secretase inhibitors or immunotherapy. Furthermore, the normal neuronal functions of APP and its various metabolites still remain under-investigated and unclear. Here, we highlight emerging areas of APP function that may provide new insights into synaptic development, cognition, and gene regulation. By modulating expression levels of endogenous APP in primary cortical neurons, the frequency and amplitude of calcium oscillations is modified, implying a key role for APP in maintaining neuronal calcium homeostasis essential for synaptic transmission. Disruption of this homeostatic mechanism predisposes to aging and AD. Synaptic spine loss is a feature of neurogeneration resulting in learning and memory deficits, and emerging evidence indicates a role for APP, probably mediated via one or more of its metabolites, in spine structure and functions. The intracellular domain of APP (AICD) has also emerged as a key epigenetic regulator of gene expression controlling a diverse range of genes, including APP itself, the amyloid-degrading enzyme neprilysin, and aquaporin-1. A fuller understanding of the physiological and pathological actions of APP and its metabolic network could provide new opportunities for therapeutic intervention in AD.

Octave JN; Pierrot N; Ferao Santos S; Nalivaeva NN; Turner AJ

2013-07-01

267

Human chorionic gonadotropin increases ?-cleavage of amyloid precursor protein in SH-SY5Y cells.  

Science.gov (United States)

Elevated levels of amyloid-? (A?) peptides, the main component of amyloid plaques in Alzheimer's disease, are the result of excessive ?- and ?-cleavage of the amyloid precursor protein (APP) and/or impaired A? clearance in the brain. It has been suggested that high concentrations of luteinizing hormone (LH) in women contribute to increased A? generation after menopause, but the mechanism for this is incompletely understood. We investigated the effect of human chorionic gonadotropin (hCG), an LH receptor agonist, on APP ?-cleavage in the SH-SY5Y neuroblastoma cell line. Treatment of these cells with hCG-induced elevated ?-cleavage in a dose-dependent manner: administration of 30 mIU but not 10 mIU/ml of hCG significantly increased sAPP? levels in the cell medium 1.7-fold as measured by ELISA. These results support the notion that LH contributes to elevated A? levels at least in part by increasing ?-cleavage of APP by ?-site APP cleaving enzyme. PMID:23812658

Saberi, Soheila; Du, Yan Ping; Christie, MacDonald; Goldsbury, Claire

2013-06-28

268

The interaction of beta-amyloid protein with cellular membranes stimulates its own production  

Science.gov (United States)

Summary Gradual changes in steady-state levels of beta amyloid peptides (A?) in brain are considered an initial step in the amyloid cascade hypothesis of Alzheimer's disease. A? is a product of the secretase cleavage of amyloid precursor protein (APP). There is evidence that the membrane lipid environment may modulate secretase activity and alters its function. Cleavage of APP strongly depends on membrane properties. Since A? perturbs cell membrane fluidity, the cell membrane may be the location where the neurotoxic cascade of A? is initiated. Therefore, we tested effects of oligomeric A? on membrane fluidity of whole living cells, the impact of exogenous and cellular A? on the processing of APP and the role of GM-1 ganglioside. We present evidence that oligoA?(1-40) stimulates the amyloidogenic processing of APP by reducing membrane fluidity and complexing with GM-1 ganglioside. This dynamic action of A? may start a vicious circle, where endogenous A? stimulates its own production. Based on our novel findings, we propose that oligoA?(1-40) accelerates the proteolytic cleavage of APP by decreasing membrane fluidity.

Peters, Imke; Igbavboa, Urule; Schutt, Tanja; Haidari, Schamim; Hartig, Ulrike; Bottner, Steffi; Copanaki, Ekaterini; Deller, Thomas; Kogel, Donat; Wood, W. Gibson; Muller, Walter E.; Eckert, Gunter P.

2009-01-01

269

Increased amyloid-? peptide-induced memory deficits in phospholipid transfer protein (PLTP) gene knockout mice.  

Science.gov (United States)

Oxidative stress is recognized as one of the earliest and most intense pathological processes in Alzheimer's disease (AD), and the antioxidant vitamin E has been shown to efficiently prevent amyloid plaque formation and neurodegeneration. Plasma phospholipid transfer protein (PLTP) has a major role in vitamin E transfers in vivo, and PLTP deficiency in mice is associated with reduced brain vitamin E levels. To determine the impact of PLTP on amyloid pathology in vivo, we analyzed the vulnerability of PLTP-deficient (PLTP-KO) mice to the toxic effects induced by intracerebroventricular injection of oligomeric amyloid-? 25-35 (A? 25-35) peptide, a non-transgenic model of AD. Under basal conditions, PLTP-KO mice showed increased cerebral oxidative stress, increased brain A? 1-42 levels, and a lower expression of the synaptic function marker synaptophysin, as compared with wild-type mice. This PLTP-KO phenotype was associated with increased memory impairment 1 week after A?25-35 peptide injection. Restoration of brain vitamin E levels in PLTP-KO mice through a chronic dietary supplementation prevented A? 25-35-induced memory deficits and reduced cerebral oxidative stress and toxicity. We conclude that PLTP, through its ability to deliver vitamin E to the brain, constitutes an endogenous neuroprotective agent. Increasing PLTP activity may offer a new way to develop neuroprotective therapies. PMID:23303044

Desrumaux, Catherine; Pisoni, Amandine; Meunier, Johann; Deckert, Valérie; Athias, Anne; Perrier, Véronique; Villard, Vanessa; Lagrost, Laurent; Verdier, Jean-Michel; Maurice, Tangui

2012-12-03

270

Increased amyloid-? peptide-induced memory deficits in phospholipid transfer protein (PLTP) gene knockout mice.  

UK PubMed Central (United Kingdom)

Oxidative stress is recognized as one of the earliest and most intense pathological processes in Alzheimer's disease (AD), and the antioxidant vitamin E has been shown to efficiently prevent amyloid plaque formation and neurodegeneration. Plasma phospholipid transfer protein (PLTP) has a major role in vitamin E transfers in vivo, and PLTP deficiency in mice is associated with reduced brain vitamin E levels. To determine the impact of PLTP on amyloid pathology in vivo, we analyzed the vulnerability of PLTP-deficient (PLTP-KO) mice to the toxic effects induced by intracerebroventricular injection of oligomeric amyloid-? 25-35 (A? 25-35) peptide, a non-transgenic model of AD. Under basal conditions, PLTP-KO mice showed increased cerebral oxidative stress, increased brain A? 1-42 levels, and a lower expression of the synaptic function marker synaptophysin, as compared with wild-type mice. This PLTP-KO phenotype was associated with increased memory impairment 1 week after A?25-35 peptide injection. Restoration of brain vitamin E levels in PLTP-KO mice through a chronic dietary supplementation prevented A? 25-35-induced memory deficits and reduced cerebral oxidative stress and toxicity. We conclude that PLTP, through its ability to deliver vitamin E to the brain, constitutes an endogenous neuroprotective agent. Increasing PLTP activity may offer a new way to develop neuroprotective therapies.

Desrumaux C; Pisoni A; Meunier J; Deckert V; Athias A; Perrier V; Villard V; Lagrost L; Verdier JM; Maurice T

2013-04-01

271

Human chorionic gonadotropin increases ?-cleavage of amyloid precursor protein in SH-SY5Y cells.  

UK PubMed Central (United Kingdom)

Elevated levels of amyloid-? (A?) peptides, the main component of amyloid plaques in Alzheimer's disease, are the result of excessive ?- and ?-cleavage of the amyloid precursor protein (APP) and/or impaired A? clearance in the brain. It has been suggested that high concentrations of luteinizing hormone (LH) in women contribute to increased A? generation after menopause, but the mechanism for this is incompletely understood. We investigated the effect of human chorionic gonadotropin (hCG), an LH receptor agonist, on APP ?-cleavage in the SH-SY5Y neuroblastoma cell line. Treatment of these cells with hCG-induced elevated ?-cleavage in a dose-dependent manner: administration of 30 mIU but not 10 mIU/ml of hCG significantly increased sAPP? levels in the cell medium 1.7-fold as measured by ELISA. These results support the notion that LH contributes to elevated A? levels at least in part by increasing ?-cleavage of APP by ?-site APP cleaving enzyme.

Saberi S; Du YP; Christie M; Goldsbury C

2013-08-01

272

The amyloid precursor protein: a biochemical enigma in brain development, function and disease.  

UK PubMed Central (United Kingdom)

For 20 years the amyloid cascade hypothesis of Alzheimer disease (AD) has placed the amyloid-? peptide (A?), formed from the amyloid precursor protein (APP), centre stage in the process of neurodegeneration. However, no new therapeutic agents have reached the clinic through exploitation of the hypothesis. The APP metabolites, including A?, generated by its proteolytic processing, have distinct physiological functions. In particular, the cleaved intracellular domain of APP (AICD) regulates expression of several genes, including APP itself, the ?-secretase BACE-1 and the A?-degrading enzyme, neprilysin and this transcriptional regulation involves direct promoter binding of AICD. Of the three major splice isoforms of APP (APP695, APP751, APP770), APP695 is the predominant neuronal form, from which A? and transcriptionally-active AICD are preferentially generated by selective processing through the amyloidogenic pathway. Despite intensive research, the normal functions of the APP isoforms remain an enigma. APP plays an important role in brain development, memory and synaptic plasticity and secreted forms of APP are neuroprotective. A fuller understanding of the physiological and pathological actions of APP and its metabolic and gene regulatory network could provide new therapeutic opportunities in neurodegeneration, including AD.

Nalivaeva NN; Turner AJ

2013-06-01

273

The amyloid precursor protein: a biochemical enigma in brain development, function and disease.  

Science.gov (United States)

For 20 years the amyloid cascade hypothesis of Alzheimer disease (AD) has placed the amyloid-? peptide (A?), formed from the amyloid precursor protein (APP), centre stage in the process of neurodegeneration. However, no new therapeutic agents have reached the clinic through exploitation of the hypothesis. The APP metabolites, including A?, generated by its proteolytic processing, have distinct physiological functions. In particular, the cleaved intracellular domain of APP (AICD) regulates expression of several genes, including APP itself, the ?-secretase BACE-1 and the A?-degrading enzyme, neprilysin and this transcriptional regulation involves direct promoter binding of AICD. Of the three major splice isoforms of APP (APP695, APP751, APP770), APP695 is the predominant neuronal form, from which A? and transcriptionally-active AICD are preferentially generated by selective processing through the amyloidogenic pathway. Despite intensive research, the normal functions of the APP isoforms remain an enigma. APP plays an important role in brain development, memory and synaptic plasticity and secreted forms of APP are neuroprotective. A fuller understanding of the physiological and pathological actions of APP and its metabolic and gene regulatory network could provide new therapeutic opportunities in neurodegeneration, including AD. PMID:23684647

Nalivaeva, Natalia N; Turner, Anthony J

2013-05-16

274

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

UK PubMed Central (United Kingdom)

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

Chen J; Wang M; Turko IV

2013-01-01

275

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

Science.gov (United States)

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

Straub, John

2013-03-01

276

Equimolar production of amyloid beta-protein and amyloid precursor protein intracellular domain from beta-carboxyl-terminal fragment by gamma-secretase.  

Science.gov (United States)

We showed previously that cells expressing wild-type (WT) beta-amyloid precursor protein (APP) or coexpressing WTAPP and WT presenilin (PS) 1/2 produced APP intracellular domains (AICD) 49-99 and 50-99, with the latter predominating. On the other hand, the cells expressing mutant (MT) APP or coexpressing WTAPP and MTPS1/2 produced a greater proportion of AICD-(49-99) than AICD-(50-99). In addition, the expression of amyloid beta-protein (Abeta) 49 in cells resulted in predominant production of Abeta40 and that of Abeta48 leads to preferential production of Abeta42. These observations suggest that epsilon-cleavage and gamma-cleavage are interrelated. To determine the stoichiometry between Abeta and AICD, we have established a 3-[(3-cholamidopropyl)dimethylammonio]-2-hydroxy-1-propanesulfonic acid-solubilized gamma-secretase assay system that exhibits high specific activity. By using this assay system, we have shown that equal amounts of Abeta and AICD are produced from beta-carboxyl-terminal fragment (C99) by gamma-secretase, irrespective of WT or MTAPP and PS1/2. Although various Abeta species, including Abeta40, Abeta42, Abeta43, Abeta45, Abeta48, and Abeta49, are generated, only two species of AICD, AICD-(49-99) and AICD-(50-99), are detected. We also have found that M233T MTPS1 produced only one species of AICD, AICD-(49-99), and only one for its counterpart, Abeta48, in contrast to WT and other MTPS1s. These strongly suggest that epsilon-cleavage is the primary event, and the produced Abeta48 and Abeta49 rapidly undergo gamma-cleavage, resulting in generation of various Abeta species. PMID:16595682

Kakuda, Nobuto; Funamoto, Satoru; Yagishita, Sousuke; Takami, Mako; Osawa, Satoko; Dohmae, Naoshi; Ihara, Yasuo

2006-04-04

277

Fine mapping of the amyloid ?-protein binding site on myelin basic protein.  

UK PubMed Central (United Kingdom)

The assembly and deposition of amyloid ?-protein (A?) in brain is a key pathological feature of Alzheimer's disease and related disorders. Factors have been identified that can either promote or inhibit A? assembly in brain. We previously reported that myelin basic protein (MBP) is a potent inhibitor of A? fibrillar assembly [Hoos, M. D., et al. (2007) J. Biol. Chem. 282, 9952-9961; Hoos, M. D., et al. (2009) Biochemistry 48, 4720-4727]. Moreover, the region on MBP responsible for this activity was localized to the 64 N-terminal amino acids (MBP1-64) [Liao, M. C., et al. (2010) J. Biol. Chem. 285, 35590-35598]. In the study presented here, we sought to further define the site on MBP1-64 involved in this activity. Deletion mapping studies showed that the C-terminal region (residues 54-64) is required for the ability of MBP1-64 to bind A? and inhibit fibril assembly. Alanine scanning mutagenesis revealed that amino acids K54, R55, G56, and K59 within MBP1-64 are important for both A? binding and inhibition of fibril assembly as assessed by solid phase binding, thioflavin T binding and fluorescence, and transmission electron microscopy studies. Strong spectral shifts are observed by solution nuclear magnetic resonance spectroscopy of specific N-terminal residues (E3, R5, D7, E11, and Q15) of A?42 upon the interaction with MBP1-64. Although the C-terminal region of MBP1-64 is required for interactions with A?, a synthetic MBP50-64 peptide was itself devoid of activity. These studies identify key residues in MBP and A? involved in their interactions and provide structural insight into how MBP regulates A? fibrillar assembly.

Kotarba AE; Aucoin D; Hoos MD; Smith SO; Van Nostrand WE

2013-04-01

278

The Hsp70/90 cochaperone, Sti1, suppresses proteotoxicity by regulating spatial quality control of amyloid-like proteins.  

UK PubMed Central (United Kingdom)

Conformational diseases are associated with the conversion of normal proteins into aggregation prone toxic conformers with structures similar to ?-amyloid. Spatial distribution of amyloid-like proteins into intracellular quality control centers can be beneficial, but cellular mechanisms for protective aggregation remain unclear. A high-copy suppressor screen in yeast was utilized to identify roles for the Hsp70 system in spatial organization of toxic polyglutamine expanded Huntingtin (Htt103Q) into benign assemblies. Under toxic conditions, Htt103Q accumulates in unassembled states and speckled cytosolic foci. Subtle modulation of Sti1 activity reciprocally impacts Htt toxicity and the packaging of Htt103Q into foci. Loss of Sti1 exacerbates Htt toxicity and hinders foci formation, whereas elevation of Sti1 suppresses Htt toxicity while organizing small Htt103Q foci into larger assemblies. Sti1 also suppresses cytotoxicity of the glutamine-rich yeast prion [RNQ+] while reorganizing speckled Rnq1-mRFP into distinct foci. Sti1 inducible foci are perinuclear and contain proteins that are bound by the amyloid indicator dye thioflavin-T. Sti1 is an Hsp70 cochaperone that regulates the spatial organization of amyloid-like proteins in the cytosol and thereby buffers proteotoxicity caused by amyloid-like proteins.

Wolfe KJ; Ren HY; Trepte P; Cyr DM

2013-10-01

279

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

UK PubMed Central (United Kingdom)

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

Copas VE; Durham AE; Stratford CH; McGorum BC; Waggett B; Pirie RS

2013-04-01

280

Serum prolyl hydroxylase protein in experimental liver cancer.  

Science.gov (United States)

Total prolyl hydroxylase protein was measured in serum of rats fed with 0.06% of azodye, 3-methyl-4-dimethyl-aminoazobenzene (3-MeDAB). Serum enzyme protein values in the group progressing to primary hepatoma and those which had the tumors were significantly different (p less than 0.001) from the controls. The results suggest that the assay of serum prolyl hydroxylase protein may be an additional useful tool in the diagnosis of primary hepatic cancer. PMID:2839006

Bolarin, D M

1988-01-01

 
 
 
 
281

Serum prolyl hydroxylase protein in experimental liver cancer.  

UK PubMed Central (United Kingdom)

Total prolyl hydroxylase protein was measured in serum of rats fed with 0.06% of azodye, 3-methyl-4-dimethyl-aminoazobenzene (3-MeDAB). Serum enzyme protein values in the group progressing to primary hepatoma and those which had the tumors were significantly different (p less than 0.001) from the controls. The results suggest that the assay of serum prolyl hydroxylase protein may be an additional useful tool in the diagnosis of primary hepatic cancer.

Bolarin DM

1988-01-01

282

Bence-Jones protein-type myeloma with amyloid myopathy presenting as amyloidomas and extensive amyloid deposits in the muscularis propria: a rapidly fatal autopsy case.  

UK PubMed Central (United Kingdom)

This study reports a 59-year-old man who suffered from multiple skeletal muscle amyloidomas and showed a rapidly fatal course. He noticed left inguinal pain and gait disturbance due to muscle weakness of the left leg. Protein in urine (3.3 g/d) and Bence-Jones protein of the ? type (2.3 g/d) were detected. Bone marrow aspiration showed 11.6% monoclonal plasma cells in nucleated cells. A core needle-biopsied and resected left inguinal tumor showed the deposition of eosinophilic amorphous materials positive for Congo red stain and the ?-light chain. He was diagnosed with plasma cell myeloma with AL (amyloid light chain) amyloidosis. Multiple soft-part tumors developed, grew rapidly, and he died 3 months after admission. At autopsy, 3 large amyloidomas were observed in the skeletal muscles, and prominent amyloid deposits were also seen in the diaphragm, intercostal muscle, iliopsoas muscle, and cervical skeletal muscles examined. Massive amyloid materials deposited diffusely in the propria muscularis of the gastrointestinal tract: the tongue to the rectum.

Ikezawa Y; Oka K; Nagayama R; Okubo Y; Yonekawa N; Hirai F; Ebihara I; Mori N

2012-02-01

283

Bence-Jones protein-type myeloma with amyloid myopathy presenting as amyloidomas and extensive amyloid deposits in the muscularis propria: a rapidly fatal autopsy case.  

Science.gov (United States)

This study reports a 59-year-old man who suffered from multiple skeletal muscle amyloidomas and showed a rapidly fatal course. He noticed left inguinal pain and gait disturbance due to muscle weakness of the left leg. Protein in urine (3.3 g/d) and Bence-Jones protein of the ? type (2.3 g/d) were detected. Bone marrow aspiration showed 11.6% monoclonal plasma cells in nucleated cells. A core needle-biopsied and resected left inguinal tumor showed the deposition of eosinophilic amorphous materials positive for Congo red stain and the ?-light chain. He was diagnosed with plasma cell myeloma with AL (amyloid light chain) amyloidosis. Multiple soft-part tumors developed, grew rapidly, and he died 3 months after admission. At autopsy, 3 large amyloidomas were observed in the skeletal muscles, and prominent amyloid deposits were also seen in the diaphragm, intercostal muscle, iliopsoas muscle, and cervical skeletal muscles examined. Massive amyloid materials deposited diffusely in the propria muscularis of the gastrointestinal tract: the tongue to the rectum. PMID:21632635

Ikezawa, Yoshiyasu; Oka, Kuniyuki; Nagayama, Reizo; Okubo, Yuki; Yonekawa, Nobuo; Hirai, Futoshi; Ebihara, Itaru; Mori, Naoyoshi

2011-06-01

284

Endolysosome involvement in HIV-1 transactivator protein-induced neuronal amyloid beta production.  

UK PubMed Central (United Kingdom)

The increased life expectancy of people living with HIV-1/AIDS is accompanied by increased prevalence of HIV-1-associated neurocognitive disorder. As well, these individuals are increasingly experiencing Alzheimer's disease (AD)-like neurocognitive problems and neuropathological features such as increased deposition of amyloid beta (A?) protein. Findings that A? production occurs largely in endolysosomes, that HIV-1 transactivator protein (Tat) disrupts endolysosome function-an early pathological feature of AD-and that HIV-1 Tat can increase A? levels prompted us to test the hypothesis that endolysosome dysfunction is associated with HIV-1 Tat-induced increases in neuronal A? generation. Using primary cultured rat hippocampal neurons, we found that treatment with HIV-1 Tat caused such morphological changes as enlargement of endolysosomes identified with LysoTracker dye and such functional changes as elevated endolysosome pH measured ratiometrically with LysoSensor dye. The HIV-1 Tat-induced changes in endolysosome function preceded temporally HIV-1 Tat-induced increases in A? generation measured using enzyme-linked immunosorbent assay. In addition, we demonstrated that HIV-1 Tat increased endolysosome accumulation of A? precursor protein and A? identified using immunostaining with 4G8 antibodies. Furthermore, we demonstrated that treatment of neurons with HIV-1 Tat increased endolysosome accumulation of beta amyloid-converting enzyme, the rate-limiting enzymatic step for A? production, and enhanced beta amyloid-converting enzyme activity. Together, our findings suggest that HIV-1 Tat increases neuronal A? generation and thereby contributes to the development of AD-like pathology in HIV-1-infected individuals by disturbing endolysosome structure and function.

Chen X; Hui L; Geiger NH; Haughey NJ; Geiger JD

2013-10-01

285

Beta-amyloid precursor protein is modified with O-linked N-acetylglucosamine.  

UK PubMed Central (United Kingdom)

The beta-amyloid precursor protein (APP) has been implicated in the etiology of Alzheimer's disease (Kang et al.: Nature 325:733-736, 1987; Selkoe: Science 248:1058-1060, 1990; Selkoe: In Cowan et al. (eds): "Annual Review of Neuroscience." Palo Alto, CA: Annual Reviews, Inc., pp 489-519, 1994) and numerous studies have shown that beta-amyloid is involved in amyloid plaque formation (Rumble et al.: N Engl J Med 320:1446-1452, 1989; Sisodia et al.: Science 248: 492-495, 1990). Evidence is presented that APP is modified with N-acetylglucosamine linked to cytoplasmic serine or threonine residues (O-GlcNAc). This is the first report of a plasma membrane protein modified with this carbohydrate. It has been postulated that this modification, which is ubiquitous in all organisms studied to date except bacteria (Haltiwanger et al.: Biochem Soc Trans 20:264-269, 1992; Dong et al.: J Biol Chem 268:16679-16687, 1993; Elliot et al.: J Neurosci 13:2424-2429, 1993; Kelly et al.: J Biol Chem 268:10416-10424, 1993), may function as an alternative to phosphorylation (Dong et al., 1993) and is involved in the multimerization of proteins (Haltiwanger et al., 1992; Dong et al., 1993). O-GlcNAc occurs at "PEST" sequences (Rogers et al.: Science 234:364-368, 1986) and it has been suggested that this modification within such a sequence leads to increased proteolytic stability of the molecule (Dong et al., 1993).(ABSTRACT TRUNCATED AT 250 WORDS)

Griffith LS; Mathes M; Schmitz B

1995-06-01

286

Serum protein profiles in myasthenia gravis.  

UK PubMed Central (United Kingdom)

BACKGROUND: The diagnosis of myasthenia gravis (MG) remains challenging. We performed a proteome-wide search for potential serum protein diagnostic markers for MG using surface-enhanced laser desorption/ionization (SELDI) time-of-flight mass spectrometry (TOFMS). METHODS: Proteomic spectra from 80 MG patients and 80 healthy individuals were generated by SELDI. Samples from 56 MG patients and 56 healthy individuals in the training set were analyzed to set up the decision tree. Samples from 24 MG patients and 24 healthy individuals were used for cross-validation testing. RESULTS: The SELDI TOFMS analysis generated 101 peaks, representing differentially expressed proteins between 1000 and 20000 Da. Among them, 9 peaks were down-regulated and 30 others were up-regulated in the MG sera compared with the controls. The decision tree used the peak at M4168.94 Da and M1122.57 Da as splitters in the classification process. In the training set, 112 samples were classified as MG or control group, with a sensitivity of 100% and specificity of 89.3%; the 10-fold cross-validated analysis identified the optimal decision tree with the lowest relative cross-validated cost of 0.080. In the test set, the decision tree generated was able to identify 20 of 24 MG patients and 21 of 24 healthy individuals with a sensitivity of 83.3% and a specificity of 87.5%. CONCLUSIONS: SELDI TOFMS is a useful tool for the detection and identification of potential serum biomarkers that can diagnose MG with high sensitivity and specificity.

Cheng C; Wu G; Yeung SC; Li R; Bella AE; Pang J; Zhong FT; Luo H; Jin Y; Pan J

2009-10-01

287

The effects of aggregation-inducing motifs on amyloid formation of model proteins related to neurodegenerative diseases.  

Science.gov (United States)

To examine the effects of aggregation-inducing motifs related to neurodegenerative diseases on amyloid formation of host protein, we prepared several chimera myoglobins, in which various aggregation-inducing motifs were inserted. The focused aggregation-inducing motifs included five (R5) or two (R2) oligopeptide repeats in yeast Sup35p, five octapeptide repeats (OPR) in the human prion protein, a nonamyloid beta component (NAC) in alpha-synuclein, and tandem repeats of 50 glutamines (Q50). Circular dichroism and infrared spectroscopies suggested that the OPR, R5, and Q50 motifs formed an antiparallel beta sheet as well as a random coil, whereas the R2 and NAC motifs mainly formed random coils. The OPR, R5, and Q50 mutants, but not the R2 and NAC mutants, readily formed the SDS-resistant aggregates under physiological condition, and electron microscopy revealed that the aggregates contained amyloid fibrils. The destabilization and increase in gyration radius of the OPR, R5, and Q50 mutants correlated with the tendency to form amyloid fibrils. A control mutant bearing a nonamyloidgenic sequence was also moderately destabilized but did not form amyloid fibrils. Therefore, we concluded that the OPR, R5, and Q50 motifs, even in a quite stable protein such as myoglobin, led the host protein to formation of amyloid fibrils under physiological condition. PMID:12162743

Tanaka, Motomasa; Machida, Yoko; Nishikawa, Yukihiro; Akagi, Takumi; Morishima, Isao; Hashikawa, Tsutomu; Fujisawa, Tetsuro; Nukina, Nobuyuki

2002-08-13

288

A multipurpose fusion tag derived from an unstructured and hyperacidic region of the amyloid precursor protein.  

UK PubMed Central (United Kingdom)

Expression and purification of aggregation-prone and disulfide-containing proteins in Escherichia coli remains as a major hurdle for structural and functional analyses of high-value target proteins. Here, we present a novel gene-fusion strategy that greatly simplifies purification and refolding procedure at very low cost using a unique hyperacidic module derived from the human amyloid precursor protein. Fusion with this polypeptide (dubbed FATT for Flag-Acidic-Target Tag) results in near-complete soluble expression of variety of extracellular proteins, which can be directly refolded in the crude bacterial lysate and purified in one-step by anion exchange chromatography. Application of this system enabled preparation of functionally active extracellular enzymes and antibody fragments without the need for condition optimization.

Sangawa T; Tabata S; Suzuki K; Saheki Y; Tanaka K; Takagi J

2013-06-01

289

Absence of A673T amyloid-? precursor protein variant in Alzheimer's disease and other neurological diseases.  

Science.gov (United States)

The rare variant A673T in the amyloid-? precursor protein (APP) gene has been shown to reduce the risk of cognitive impairment. We genotyped the variant in 8721 Asian individuals comprising 552 with Alzheimer's disease and vascular dementia, 790 with Parkinson's disease, and 7379 controls. The A673T variant was absent in all of the subjects. Our finding suggests that the A673T protective variant is not relevant in our Asian population. Studies in other ethnic populations would clarify whether this variant is specific to specific races/ethnicities. PMID:23652020

Ting, Simon Kang Seng; Chong, Mei-Sian; Kandiah, Nagaendran; Hameed, Shahul; Tan, Louis; Au, Wing-Lok; Prakash, Kumar M; Pavanni, Ratnagopal; Lee, Tih-Shih; Foo, Jia-Nee; Bei, Jin-Xin; Yu, Xue-Qing; Liu, Jian-Jun; Zhao, Yi; Lee, Wei-Ling; Tan, Eng-King

2013-05-04

290

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

291

Amyloid imaging in clinical trials.  

UK PubMed Central (United Kingdom)

The possibility to map amyloid-beta, the Alzheimer's disease hallmark protein, in vivo opens the application for amyloid imaging in clinical trials with disease-modifying agents. Monitoring change in amyloid burden, particularly when potential amyloid-lowering drugs are at play, requires accurate analytical methods. Studies to date have used suboptimal methods that do not account for heterogeneous changes in flow associated with disease progression and potentially with anti-amyloid drugs. In this commentary, we discuss practical and methodological issues regarding longitudinal amyloid imaging and propose several quantitative, yet feasible, alternatives for reliable assessment of changes over time in amyloid burden.

Ossenkoppele R; Prins ND; van Berckel BN

2013-08-01

292

Expression of active secreted forms of human amyloid beta-protein precursor by recombinant baculovirus-infected insect cells.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Three alternatively spliced forms of the amyloid precursor protein (APP), APP-695, APP-751, and APP-770, were expressed in the baculovirus expression vector system. The recombinant proteins were secreted into the culture medium by infected insect cells, and APP molecules were detected in insect cell...

Bhasin, R; Van Nostrand, W E; Saitoh, T; Donets, M A; Barnes, E A; Quitschke, W W; Goldgaber, D

293

Advanced solid-state NMR approaches for structure determination of membrane proteins and amyloid fibrils.  

Science.gov (United States)

Solid-state NMR (SSNMR) spectroscopy has become an important technique for studying the biophysics and structure biology of proteins. This technique is especially useful for insoluble membrane proteins and amyloid fibrils, which are essential for biological functions and are associated with human diseases. In the past few years, as major contributors to the rapidly advancing discipline of biological SSNMR, we have developed a family of methods for high-resolution structure determination of microcrystalline, fibrous, and membrane proteins. Key developments include order-of-magnitude improvements in sensitivity, resolution, instrument stability, and sample longevity under data collection conditions. These technical advances now enable us to apply new types of 3D and 4D experiments to collect atomic-resolution structural restraints in a site-resolved manner, such as vector angles, chemical shift tensors, and internuclear distances, throughout large proteins. In this Account, we present the technological advances in SSNMR approaches towards protein structure determination. We also describe the application of those methods for large membrane proteins and amyloid fibrils. Particularly, the SSNMR measurements of an integral membrane protein DsbB support the formation of a charge-transfer complex between DsbB and ubiquinone during the disulfide bond transfer pathways. The high-resolution structure of the DsbA-DsbB complex demonstrates that the joint calculation of X-ray and SSNMR restraints for membrane proteins with low-resolution crystal structure is generally applicable. The SSNMR investigations of ?-synuclein fibrils from both wild type and familial mutants reveal that the structured regions of ?-synuclein fibrils include the early-onset Parkinson's disease mutation sites. These results pave the way to understanding the mechanism of fibrillation in Parkinson's disease. PMID:23659727

Tang, Ming; Comellas, Gemma; Rienstra, Chad M

2013-05-10

294

Preliminary proteomic-based identification of a novel protein for Down's syndrome in maternal serum.  

UK PubMed Central (United Kingdom)

Prenatal screening for Down's syndrome (DS) is in need of improvement. As a powerful platform, proteomics techniques could also be used for identification of new biomarkers for DS screening. In this case-control proteome study, pregnant women were diagnosed prenatally by karyotype analysis from amniotic fluid (AF). Maternal serum samples were collected from six pregnancies with fetuses affected by DS and six pregnancies with normal fetuses. First, we used two-dimensional electrophoresis and mass spectrometry to identify the different levels of expression of proteins in maternal serum between the DS and control groups in the second trimester. Second, we used bioinformatics to analyze the proteins by DAVID. Then, the interesting candidates were further tested by enzyme-linked immunosorbent assay (ELISA). Twenty-nine proteins were successfully identified in maternal serum obtained from pregnancies with fetuses affected by DS. The top five proteins up-regulated were serotransferrin (TF), alpha-1b-glycoprotein (A1BG), desmin (DES), alpha-1-antitrypsin (SERPINA1) and ceruloplasmin (CP), while serum amyloid P-component (APCS) was the most down-regulated protein. These 29 proteins were categorized based on binding, catalytic activity and enzyme regulator activity. The biological roles were involved in biological regulation, metabolic processes, cellular processes and response to a stimulus. Based on ELISA, the median concentrations of CP and complement factor B (CFB) were 332.3 and 412.3 ng/mL, respectively. The concentrations of CP and CFB were significantly higher in the DS group than in the control group (P < 0.05). In conclusion, proteomic approaches offer the possibility of further improving the performance of DS screening and our identification of up- and down-regulated proteins may lead to new candidates for DS screening.

Yu B; Zhang B; Wang J; Wang QW; Huang RP; Yang YQ; Shao SH

2012-05-01

295

Aggregation of model amyloid insulin protein in crowding environments and under ac-electric fields  

Science.gov (United States)

In vitro experiments have been widely used to characterize the misfolding/unfolding pathway characteristic of amylodogenic proteins. Conversion from natively folded amyloidogenic proteins to oligomers via nucleation is the accepted path to fibril formation upon heating over a certain lag time period. In this work, we investigate the effect of crowing environment and external electric fields on the pathway and kinetics of insulin, a well-established amyloid model protein by single fluorescence spectroscopy and imaging. With added co-solutes, such as glycerol and polyvinylpyrrolidone (PVP), to mimic the cellular crowding environments, we have observed that the lag time can be significantly prolonged. The lag time increases with increasing co-solute concentration, yet showing little dependence on solution viscosity. Conversely, applied ac-electric fields can considerably shorten the lag timewhen a critical ac-voltage is exceeded. The strong dependence of lag time on ac-frequency over a narrow range of 500 Hz-5 kHz indicates the effect of ac-electroosmosis on the diffusion controlled process of insulin nucleation. Yet, no conformational structure is detected with insulin under applied ac-fields, suggesting the equivalence of ac-polarization to the conventional thermal activation process for insulin aggregation. These finding suggest that at least the aggregation kinetics of insulin can be altered by local solution condition or external stimuli, which gives new insight to the treatment of amyloid related diseases.

Zheng, Zhongli; Jing, Benxin; Murray, Brian; Sorci, Mirco; Belfort, Georges; Zhu, Y. Elaine

2013-03-01

296

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Patterson, D; Gardiner, K; Kao, F T; Tanzi, R; Watkins, P; Gusella, J F

297

On the subject of rigor in the study of amyloid ?-protein assembly.  

UK PubMed Central (United Kingdom)

According to Thomas Kuhn, the success of 'normal science,' the science we all practice on a daily basis, depends on the adherence to, and practice of, a paradigm accepted by the scientific community. When great scientific upheavals occur, they involve the rejection of the current paradigm in favor of a new paradigm that better integrates the facts available and better predicts the behavior of a particular scientific system. In the field of Alzheimer's disease, a recent example of such a paradigm shift has been the apparent rejection of the 'amyloid cascade hypothesis,' promulgated by Hardy and Higgins in 1992 to explain the etiology of Alzheimer's disease, in favor of what has been referred to as the 'oligomer cascade hypothesis'. This paradigm shift has been breathtaking in its rapidity, its pervasiveness in the Alzheimer's disease field, and its adoption in an increasing number of other fields, including those of Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and the prionoses. However, these facts do not mean, a priori, that the experiments extant, and any re-interpretation of them, should be accepted by rote as support for the new paradigm. In the discussion that follows, I consider the foundational studies leading to the oligomer cascade hypothesis and evaluate the current state of the paradigm. I argue here that, more often than not, insufficient rigor has been applied in studies upon which this new paradigm has been based. Confusion, rather than clarity, has resulted. If the field is to make progress forward using as its paradigmatic basis amyloid ?-protein oligomerization, then an epistemological re-evaluation of the amyloid ?-protein oligomer system is required.

Teplow DB

2013-08-01

298

Serum amyloid A is independently related to apolipoprotein A-I but not to HDL-cholesterol in patients with angina pectoris.  

UK PubMed Central (United Kingdom)

BACKGROUND: Inflammation processes are considered important links between classical lipid risk factors and the progression of atherosclerosis. The interrelationship of high density lipoproteins (HDL) and apolipoprotein apoA-1 with acute phase proteins and cytokines was examined in a clinical setting of patients with angina pectoris. METHODS: On exclusion criteria (myocardial infarction, heart failure, CHD>2years, anticoagulant therapy), 198 patients were recruited and were subdivided according to angiographically documented stenosis, no stenosis vs. =50% stenosis, in accordance with CASS guidelines. Lipids, apoA-1 and apoB, C-reactive protein (hs-CRP), fibrinogen, serum amyloid A (SAA) and cytokines (IL-6, IL-8, IL-10, IL2R, TNF?) were measured. RESULTS: Low HDL-C (and apoA-I) is associated with advanced coronary stenosis (=50%) and with the number of diseased vessels, independent of age, gender, diabetes, smoking and lipid-lowering therapy. In contrast to hs-CRP and fibrinogen, SAA as well as cytokine levels were not significantly associated with stenosis. SAA (P=0.0003) and diabetes (P=0.0002) were strong predictors of apoA-I concentration independent of age, gender, BMI, smoking, CRP, as well as IL-6 in a multiple regression model. High SAA (P=0.0067) and TG (P=0.0123) were significant predictors of apoA-I/HDL-C ratio. However, SAA was not independently related to HDL-C. CONCLUSIONS: SAA is independently and inversely related to apoA-I but not to HDL-C in patients with angina pectoris, reflecting the effect of SAA on the quality of HDL particles. However, HDL-c but not SAA is inversely related to the degree of coronary artery stenosis.

Korita I; Bulo A; Langlois MR; Verhoye E; Blaton V

2013-08-01

299

?-Site amyloid precursor protein-cleaving enzyme 1 activity is related to cerebrospinal fluid concentrations of sortilin-related receptor with A-type repeats, soluble amyloid precursor protein, and tau.  

UK PubMed Central (United Kingdom)

BACKGROUND: ?-Site amyloid precursor protein (APP)-cleaving enzyme 1 (BACE1) activity determines the rate of APP cleavage and is therefore the main driver of amyloid ? production, which is a pathological hallmark of Alzheimer's disease (AD). METHODS: The present study explored the correlation between BACE1 activity and cerebrospinal fluid (CSF) markers of APP metabolism and axonal degeneration in 63 patients with mild AD and 12 healthy control subjects. RESULTS: In the AD group, positive correlations between BACE1 activity and soluble APP ?, the APP sorting receptor sortilin-related receptor with A-type repeats (also known as SorLA or LR11), and tau were detected. BACE1 activity was not associated with amyloid ?1-42 or soluble APP ? concentrations in the AD group, and no associations between BACE1 activity and any of the protein concentrations were found in the control group. CONCLUSION: Our results confirm the relevance of BACE1 and sortilin-related receptor with A-type repeats within the amyloid cascade and also provide a further piece of evidence for the link between amyloid and tau pathology in AD.

Tsolakidou A; Alexopoulos P; Guo LH; Grimmer T; Westerteicher C; Kratzer M; Jiang M; Bujo H; Roselli F; Leante MR; Livrea P; Kurz A; Perneczky R

2013-07-01

300

Serum protein changes in cafeteria mice induced by starvation.  

UK PubMed Central (United Kingdom)

Serum protein changes in cafeteria and control mice induced by starvation have been studied. Animals were subjected to food deprivation at 0, 3, 6, 9, 12, 18, 24 or 36 hours. Results show a more stabilized situation in cafeteria mice than controls particularly in protein metabolism. Serum protein composition changed very little during starvation, suggests a lower protein and amino acid catabolism induced by the high adaptation to consume lipids.

Cartaña J; Huguet J; Arola L; Alemany M

1987-09-01

 
 
 
 
301

Cyclic adenosine monophosphate as an endogenous modulator of the amyloid-? precursor protein metabolism.  

Science.gov (United States)

Besides playing a pathogenic role in Alzheimer disease, amyloid-beta peptides are normally produced in low amounts in the brain, and several lines of evidence suggest that they can modulate synaptic plasticity and memory. As cyclic adenosine monophosphate (cAMP) is known to be involved in the same processes and the blockade of its degradation by phosphodiesterase 4 inhibitors has consistently shown beneficial effects on cognition, we investigated the possible correlation between this second messenger and A? peptides in neuronal N2a cells overexpressing the amyloid-? precursor protein (APP). We herein report that the elevation of endogenous cAMP by rolipram increased APP protein expression and both its amyloidogenic and nonamyloidogenic processing. The effects of rolipram were reproduced by both the cAMP membrane-permeant analog 8Br-cAMP and the forskolin-induced activation of adenylyl cyclase but were not affected by the PKA inhibitor H-89. Our results demonstrate that, in neuronal cells, APP metabolism is physiologically modulated by cAMP and suggest that this might represent an additional mechanism through which the second messenger could influence memory functions. PMID:23297063

Canepa, Elisa; Domenicotti, Cinzia; Marengo, Barbara; Passalacqua, Mario; Marinari, Umberto M; Pronzato, Maria A; Fedele, Ernesto; Ricciarelli, Roberta

2013-01-08

302

Cyclic adenosine monophosphate as an endogenous modulator of the amyloid-? precursor protein metabolism.  

UK PubMed Central (United Kingdom)

Besides playing a pathogenic role in Alzheimer disease, amyloid-beta peptides are normally produced in low amounts in the brain, and several lines of evidence suggest that they can modulate synaptic plasticity and memory. As cyclic adenosine monophosphate (cAMP) is known to be involved in the same processes and the blockade of its degradation by phosphodiesterase 4 inhibitors has consistently shown beneficial effects on cognition, we investigated the possible correlation between this second messenger and A? peptides in neuronal N2a cells overexpressing the amyloid-? precursor protein (APP). We herein report that the elevation of endogenous cAMP by rolipram increased APP protein expression and both its amyloidogenic and nonamyloidogenic processing. The effects of rolipram were reproduced by both the cAMP membrane-permeant analog 8Br-cAMP and the forskolin-induced activation of adenylyl cyclase but were not affected by the PKA inhibitor H-89. Our results demonstrate that, in neuronal cells, APP metabolism is physiologically modulated by cAMP and suggest that this might represent an additional mechanism through which the second messenger could influence memory functions.

Canepa E; Domenicotti C; Marengo B; Passalacqua M; Marinari UM; Pronzato MA; Fedele E; Ricciarelli R

2013-02-01

303

Aging renders the brain vulnerable to amyloid beta-protein neurotoxicity.  

UK PubMed Central (United Kingdom)

The formation of fibrillar deposits of amyloid beta protein (Abeta) in the brain is a pathological hallmark of Alzheimer's disease (AD). A central question is whether Abeta plays a direct role in the neurodegenerative process in AD. The involvement of Abeta in the neurodegenerative process is suggested by the neurotoxicity of the fibrillar form of Abeta in vitro. However, mice transgenic for the Abeta precursor protein that develop amyloid deposits in the brain do not show the degree of neuronal loss or tau phosphorylation found in AD. Here we show that microinjection of plaque-equivalent concentrations of fibrillar, but not soluble, Abeta in the aged rhesus monkey cerebral cortex results in profound neuronal loss, tau phosphorylation and microglial proliferation. Fibrillar Abeta at plaque-equivalent concentrations is not toxic in the young adult rhesus brain. Abeta toxicity in vivo is also highly species-specific; toxicity is greater in aged rhesus monkeys than in aged marmoset monkeys, and is not significant in aged rats. These results suggest that Abeta neurotoxicity in vivo is a pathological response of the aging brain, which is most pronounced in higher order primates. Thus, longevity may contribute to the unique susceptibility of humans to Alzheimer's disease by rendering the brain vulnerable to Abeta neurotoxicity.

Geula C; Wu CK; Saroff D; Lorenzo A; Yuan M; Yankner BA

1998-07-01

304

Specific binding of DNA to aggregated forms of Alzheimer's disease amyloid peptides.  

UK PubMed Central (United Kingdom)

Anomalous protein aggregation is closely associated to age-related mental illness. Extraneuronal plaques, mainly composed of aggregated amyloid peptides, are considered as hallmarks of Alzheimer's disease. According to the amyloid cascade hypothesis, this disease starts as a consequence of an abnormal processing of the amyloid precursor protein resulting in an excess of amyloid peptides. Nuclear localization of amyloid peptide aggregates together with amyloid-DNA interaction, have been repeatedly reported. In this paper we have used surface plasmon resonance and electron microscopy to study the structure and behavior of different peptides and proteins, including ?-lactoglobulin, bovine serum albumin, myoglobin, histone, casein and the amyloid-? peptides related to Alzheimer's disease A?25-35 and A?1-40. The main purpose of this study is to investigate whether proneness to DNA interaction is a general property displayed by aggregated forms of proteins, or it is an interaction specifically related to the aggregated forms of those particular proteins and peptides related to neurodegenerative diseases. Our results reveal that those aggregates formed by amyloid peptides show a particular proneness to interact with DNA. They are the only aggregated structures capable of binding DNA, and show more affinity for DNA than for other polyanions like heparin and polyglutamic acid, therefore strengthening the hypothesis that amyloid peptides may, by means of interaction with nuclear DNA, contribute to the onset of Alzheimer's disease.

Camero S; Ayuso JM; Barrantes A; Benítez MJ; Jiménez JS

2013-04-01

305

Effect of leuprolide on serum amyloid-? peptide levels and memory in patients with prostate cancer with biochemical recurrence.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To investigate whether prostate cancer patients receiving leuprolide demonstrated objective cognitive decline accompanied by a change in plasma levels of amyloid-?. METHODS: Between November 19, 2003, and July 21, 2008, we prospectively enrolled 50 patients with biochemical recurrence of prostate cancer and measured plasma amyloid-? peptide 40 and amyloid-? peptide 42 levels with sandwich enzyme-linked immunosorbent assay at baseline before the first leuprolide injection and at 2, 4, and 12 months. The Mini-Mental State Examination was used to assess 49 patients at baseline and at subsequent visits, and 24 were also assessed by the California Verbal Learning Test-Short Form. RESULTS: Patients were a median age of 71 years (range, 59-89 years). Compared with baseline levels, plasma amyloid-? peptide 40 levels were increased at 2 months (P=.04) and 4 months (P=.02). Age was correlated with plasma amyloid-? peptide 40 levels (P=.003) and likely accounted for this relationship. Plasma amyloid-? peptide 42 and performance on cognitive tasks did not differ from baseline, but memory measures improved slightly after baseline, most likely due to a practice effect. CONCLUSION: Leuprolide therapy was not associated with a decline in cognition or memory function or with elevated plasma amyloid short-term. Larger studies are needed to confirm these findings.

Tan WW; Heckman MG; Vishnu P; Crook JE; Younkin LH; Covil EG; Ferman TJ; Graff-Radford NR; Younkin SG; Smallridge RC; Wehle MJ; Buskirk SJ

2013-01-01

306

Standards for total serum protein assays--a collaborative study.  

UK PubMed Central (United Kingdom)

We have studied the standardization of total serum protein assay with the biuret reaction. Standard solutions were prepared from lyophilized preparations of human serum albumin and bovine serum albumin, with corrections made for volatile material and ash contents. These solutions and a solution of crystalline albumin standard were analyzed with a new stable biuret reagent, to establish absorptivity values (values for the absorbance of a 1 g/liter final reaction mixture). The mean values obtained were 0.302, 0.292, and 0.290 for human serum albumin, bovine serum albumin, and the crystalline albumin, respectively. We believe that the established absorptivity value will improve the accuracy of serum protein determinations. We studied the linearity of the relation between color produced and protein concentration, with use of the solutions described above and a serum pool. The color adheres to Beer's law up to the highest concentration tested: 3 g/liter for HSA and BSA, and 2.8 g/liter for serum in the final reaction mixture. The new biuret reagent has been stable for one year at room temperature. We recommend the use of bovine serum albumin as a primary standard for serum protein assays. It is inexpensive, easily available, and exhibits the best linearity in the biuret reaction.

Doumas BT

1975-07-01

307

Standards for total serum protein assays--a collaborative study.  

Science.gov (United States)

We have studied the standardization of total serum protein assay with the biuret reaction. Standard solutions were prepared from lyophilized preparations of human serum albumin and bovine serum albumin, with corrections made for volatile material and ash contents. These solutions and a solution of crystalline albumin standard were analyzed with a new stable biuret reagent, to establish absorptivity values (values for the absorbance of a 1 g/liter final reaction mixture). The mean values obtained were 0.302, 0.292, and 0.290 for human serum albumin, bovine serum albumin, and the crystalline albumin, respectively. We believe that the established absorptivity value will improve the accuracy of serum protein determinations. We studied the linearity of the relation between color produced and protein concentration, with use of the solutions described above and a serum pool. The color adheres to Beer's law up to the highest concentration tested: 3 g/liter for HSA and BSA, and 2.8 g/liter for serum in the final reaction mixture. The new biuret reagent has been stable for one year at room temperature. We recommend the use of bovine serum albumin as a primary standard for serum protein assays. It is inexpensive, easily available, and exhibits the best linearity in the biuret reaction. PMID:1169135

Doumas, B T

1975-07-01

308

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

309

Expressions of amyloid precursor protein, synaptophysin and presenilin-1 in the different areas of the developing cerebellum of rat.  

UK PubMed Central (United Kingdom)

This study reveals the expressions of Alzheimer's disease-related amyloid precursor protein, presenilin-1, and a presynaptic marker protein, synaptophysin, in the archi-, paleo- and neocerebellum during the postnatal development of the rat. The Western blot results demonstrate a gradual increase in the soluble amyloid precursor protein level in the archicerebellum during the first 3 weeks, while in the neo- and paleocerebellum the levels reach a plateau as early as the 1st week. Immunohistochemically, the protein is present in the deep part of the external granule cell layer and the internal granule cell layer in the newborn animal, while in 3-week-old animals the staining appears mainly in the perikarya and dendrites of the Purkinje cells. The level of synaptophysin increases progressively from postnatal day 7 up to 3 weeks in the archi- and paleocerebellum, and up to 6 weeks in the neocerebellum. Immunohistochemically, the amyloid precursor protein staining appears first in the inner part of the molecular layer and in the internal granule cell layer. In a 3-week-old animal, synaptophysin staining is present in all areas of the cerebellar molecular layer and in the internal granule cell layer. The presenilin-1 immunohistochemical reaction appeared equally in the archi-, paleo- and neocerebellum. Much of the staining is present in the glial cells and Purkinje cells. Less immunoreactivity is observed in the Golgi cells and granule cells. It is concluded that the postnatal expressions of soluble and membrane-bound amyloid precursor protein, synaptophysin and presenilin-1 are regulated differently during the ontogenetical development of the archi-, paleo- and neocerebellum of rat. Further, the amyloid precursor protein and presenilin-1 may be present in cells which do not degenerate in Alzheimer's disease.

Fakla I; Kovacs I; Yamaguchi H; Geula C; Kasa P

2000-02-01

310

Expressions of amyloid precursor protein, synaptophysin and presenilin-1 in the different areas of the developing cerebellum of rat.  

Science.gov (United States)

This study reveals the expressions of Alzheimer's disease-related amyloid precursor protein, presenilin-1, and a presynaptic marker protein, synaptophysin, in the archi-, paleo- and neocerebellum during the postnatal development of the rat. The Western blot results demonstrate a gradual increase in the soluble amyloid precursor protein level in the archicerebellum during the first 3 weeks, while in the neo- and paleocerebellum the levels reach a plateau as early as the 1st week. Immunohistochemically, the protein is present in the deep part of the external granule cell layer and the internal granule cell layer in the newborn animal, while in 3-week-old animals the staining appears mainly in the perikarya and dendrites of the Purkinje cells. The level of synaptophysin increases progressively from postnatal day 7 up to 3 weeks in the archi- and paleocerebellum, and up to 6 weeks in the neocerebellum. Immunohistochemically, the amyloid precursor protein staining appears first in the inner part of the molecular layer and in the internal granule cell layer. In a 3-week-old animal, synaptophysin staining is present in all areas of the cerebellar molecular layer and in the internal granule cell layer. The presenilin-1 immunohistochemical reaction appeared equally in the archi-, paleo- and neocerebellum. Much of the staining is present in the glial cells and Purkinje cells. Less immunoreactivity is observed in the Golgi cells and granule cells. It is concluded that the postnatal expressions of soluble and membrane-bound amyloid precursor protein, synaptophysin and presenilin-1 are regulated differently during the ontogenetical development of the archi-, paleo- and neocerebellum of rat. Further, the amyloid precursor protein and presenilin-1 may be present in cells which do not degenerate in Alzheimer's disease. PMID:10676878

Fakla, I; Kovacs, I; Yamaguchi, H; Geula, C; Kasa, P

2000-02-01

311

Asp664 cleavage of amyloid precursor protein induces tau phosphorylation by decreasing protein phosphatase 2A activity.  

Science.gov (United States)

Caspase cleavage of amyloid precursor protein (APP) has been reported to be important in amyloid beta protein (A?)-mediated neurotoxicity. However, the underlying mechanisms are not clearly understood. In this study, we explored the effect of caspase cleavage of APP on tau phosphorylation in relation to A?. We found that Asp664 cleavage of APP increased tau phosphorylation at Thr212 and Ser262 in N2A cells and primary cultured hippocampal neurons. Compared with wild-type APP, protein phosphatase 2A (PP2A) activity was significantly increased when Asp664 cleavage was blocked by the D664A point mutation. Furthermore, we found that over-expression of C31 reduced PP2A activity. C31 binds directly to the PP2A catalytic subunit, through the asparagine, proline, threonine, tyrosine (NPTY) motif, which is essential for C31-induced tau hyperphosphorylation. However, it appears that the other fragment produced by Asp664 cleavage, Jcasp, modulates neither PP2A activity nor tau hyperphosphorylation. Asp664 cleavage and accompanying tau hyperphosphorylation were remarkably diminished by blockage of A? production using a ?-secretase inhibitor. Taken together, our results suggest that Asp664 cleavage of APP leads to tau hyperphosphorylation at specific epitopes by modulating PP2A activity as a downstream of A?. Direct binding of C31 to PP2A through the C31-NPTY domain was identified as a mechanism underlying this effect. PMID:23020770

Park, Seok Soon; Jung, Hyun-Jung; Kim, Yoon-Jeong; Park, Tae Kwan; Kim, Chaeyoung; Choi, Heesun; Mook-Jung, In Hee; Koo, Edward H; Park, Sun Ah

2012-10-25

312

Asp664 cleavage of amyloid precursor protein induces tau phosphorylation by decreasing protein phosphatase 2A activity.  

UK PubMed Central (United Kingdom)

Caspase cleavage of amyloid precursor protein (APP) has been reported to be important in amyloid beta protein (A?)-mediated neurotoxicity. However, the underlying mechanisms are not clearly understood. In this study, we explored the effect of caspase cleavage of APP on tau phosphorylation in relation to A?. We found that Asp664 cleavage of APP increased tau phosphorylation at Thr212 and Ser262 in N2A cells and primary cultured hippocampal neurons. Compared with wild-type APP, protein phosphatase 2A (PP2A) activity was significantly increased when Asp664 cleavage was blocked by the D664A point mutation. Furthermore, we found that over-expression of C31 reduced PP2A activity. C31 binds directly to the PP2A catalytic subunit, through the asparagine, proline, threonine, tyrosine (NPTY) motif, which is essential for C31-induced tau hyperphosphorylation. However, it appears that the other fragment produced by Asp664 cleavage, Jcasp, modulates neither PP2A activity nor tau hyperphosphorylation. Asp664 cleavage and accompanying tau hyperphosphorylation were remarkably diminished by blockage of A? production using a ?-secretase inhibitor. Taken together, our results suggest that Asp664 cleavage of APP leads to tau hyperphosphorylation at specific epitopes by modulating PP2A activity as a downstream of A?. Direct binding of C31 to PP2A through the C31-NPTY domain was identified as a mechanism underlying this effect.

Park SS; Jung HJ; Kim YJ; Park TK; Kim C; Choi H; Mook-Jung IH; Koo EH; Park SA

2012-12-01

313

Sortilin and SorLA display distinct roles in processing and trafficking of amyloid precursor protein.  

UK PubMed Central (United Kingdom)

The development and progression of Alzheimer's disease is linked to excessive production of toxic amyloid-? peptide, initiated by ?-secretase cleavage of the amyloid precursor protein (APP). In contrast, soluble APP? (sAPP?) generated by the ?-secretase is known to stimulate dendritic branching and enhance synaptic function. Regulation of APP processing, and the shift from neurotrophic to neurotoxic APP metabolism remains poorly understood, but the cellular localization of APP and its interaction with various receptors is considered important. We here identify sortilin as a novel APP interaction partner. Like the related APP receptor SorLA, sortilin is highly expressed in the CNS, but whereas SorLA mainly colocalizes with APP in the soma, sortilin interacts with APP in neurites. The presence of sortilin promotes ?-secretase cleavage of APP, unlike SorLA, which inhibits the generation of all soluble products. Also, sortilin and SorLA both bind and mediate internalization of sAPP but to different cellular compartments. The interaction involves the 6A domain of APP, present in both neuronal and non-neuronal APP isoforms. This is important as sAPP receptors described so far only bind the non-neuronal isoforms, leaving SorLA and sortilin as the only receptors for sAPP generated by neurons. Together, our findings establish sortilin, as a novel APP interaction partner that influences both production and cellular uptake of sAPP.

Gustafsen C; Glerup S; Pallesen LT; Olsen D; Andersen OM; Nykjær A; Madsen P; Petersen CM

2013-01-01

314

Beta-secretase-cleaved amyloid precursor protein in Alzheimer brain: a morphologic study  

DEFF Research Database (Denmark)

beta-amyloid (Abeta) is the main constituent of senile plaques seen in Alzheimer's disease. Abeta is derived from the amyloid precursor protein (APP) via proteolytic cleavage by proteases beta- and gamma-secretase. In this study, we examined content and localization of beta-secretase-cleaved APP (beta-sAPP) in brain tissue sections from the frontal, temporal and occipital lobe. Strong granular beta-sAPP staining was found throughout the gray matter of all three areas, while white matter staining was considerably weaker. beta-sAPP was found to be localized in astrocytes and in axons. We found the beta-sAPP immunostaining to be stronger and more extensive in gray matter in Alzheimer disease (AD) cases than controls. The axonal beta-sAPP staining was patchy and unevenly distributed for the AD cases, indicating impaired axonal transport. beta-sAPP was also found surrounding senile plaques and cerebral blood vessels. The results presented here show altered beta-sAPP staining in the AD brain, suggestive of abnormalprocessing and transport of APP.

Sennvik, Kristina; Bogdanovic, N

2004-01-01

315

Amyloid-? Inhibits Thrombospondin 1 Release From Cultured Astrocytes: Effects on Synaptic Protein Expression.  

Science.gov (United States)

Among the consequences of Alzheimer disease are disturbances in synaptic integrity that ultimately lead to impaired cognitive functions. Thrombospondins are extracellular matrix proteins that, in the CNS, are predominantly produced by astrocytes and have been implicated in synaptogenesis. This study examined the effects of amyloid-? (A?1-42; A?) peptide on intracellular and extracellular levels of thrombospondin 1 (TSP-1) in cultured astrocytes. Amyloid-? caused a significant (1- to 3-fold) increase in astrocytic intracellular levels of TSP-1 (increased retention) that was associated with a reduction of its release from astrocytes. Because A? is known to induce oxidative stress in astrocytes, we examined the effects of the antioxidants tempol and apocynin on astrocytic TSP-1 levels and release. Treatment of A?-exposed astrocyte cultures with antioxidants significantly diminished its cellular retention and stimulated its release. Furthermore, the addition of conditioned media derived from A?-treated cultured astrocytes that contained a reduced TSP-1 content resulted in a significant loss of synaptophysin and PSD95 in cultured neurons. These findings suggest that A?-mediated reduction in astrocytic TSP-1 release, possibly related to oxidative stress, contributes to the loss of synaptophysin in neurons. Strategies aimed at enhancing the astrocytic release of TSP-1 may have a therapeutic benefit in Alzheimer disease. PMID:23860027

Rama Rao, Kakulavarapu V; Curtis, Kevin M; Johnstone, Joshua T; Norenberg, Michael D

2013-08-01

316

Amyloid-? Inhibits Thrombospondin 1 Release From Cultured Astrocytes: Effects on Synaptic Protein Expression.  

UK PubMed Central (United Kingdom)

Among the consequences of Alzheimer disease are disturbances in synaptic integrity that ultimately lead to impaired cognitive functions. Thrombospondins are extracellular matrix proteins that, in the CNS, are predominantly produced by astrocytes and have been implicated in synaptogenesis. This study examined the effects of amyloid-? (A?1-42; A?) peptide on intracellular and extracellular levels of thrombospondin 1 (TSP-1) in cultured astrocytes. Amyloid-? caused a significant (1- to 3-fold) increase in astrocytic intracellular levels of TSP-1 (increased retention) that was associated with a reduction of its release from astrocytes. Because A? is known to induce oxidative stress in astrocytes, we examined the effects of the antioxidants tempol and apocynin on astrocytic TSP-1 levels and release. Treatment of A?-exposed astrocyte cultures with antioxidants significantly diminished its cellular retention and stimulated its release. Furthermore, the addition of conditioned media derived from A?-treated cultured astrocytes that contained a reduced TSP-1 content resulted in a significant loss of synaptophysin and PSD95 in cultured neurons. These findings suggest that A?-mediated reduction in astrocytic TSP-1 release, possibly related to oxidative stress, contributes to the loss of synaptophysin in neurons. Strategies aimed at enhancing the astrocytic release of TSP-1 may have a therapeutic benefit in Alzheimer disease.

Rama Rao KV; Curtis KM; Johnstone JT; Norenberg MD

2013-08-01

317

Amyloid beta proteins reduce the GABA-induced Cl- current in identified Aplysia neurons.  

Science.gov (United States)

The amyloid beta protein (A beta P) is the major component of the amyloid deposition which characterizes Alzheimer's disease. Effects of extracellularly applied A beta P on the gamma-aminobutyric acid (GABA)-induced Cl- current recorded from identified neurons (R9 and R12) of Aplysia kurodai were investigated with conventional voltage-clamp and pressure ejection techniques. Focal application of 100 nM A beta P (1-40) reduced the GABA-induced hyperpolarization at resting membrane potential and the GABA-induced Cl- current in the neurons held at -50 mV. Bath-applied 100 nM A beta P fragments (1-40) and (25-35) but not A beta P (1-16) inhibited the GABA-induced Cl- current as well as muscimol-induced Cl- currents in the neurons without affecting the resting membrane conductance or holding current. These results suggest that A beta P may increase neuronal excitability by inhibiting GABA-induced Cl- current in the neurons of mammalian central nervous system. PMID:8873152

Sawada, M; Ichinose, M

1996-08-01

318

Sortilin and SorLA Display Distinct Roles in Processing and Trafficking of Amyloid Precursor Protein  

DEFF Research Database (Denmark)

The development and progression of Alzheimer's disease is linked to excessive production of toxic amyloid-? peptide, initiated by ?-secretase cleavage of the amyloid precursor protein (APP). In contrast, soluble APP? (sAPP?) generated by the ?-secretase is known to stimulate dendritic branching and enhance synaptic function. Regulation of APP processing, and the shift from neurotrophic to neurotoxic APP metabolism remains poorly understood, but the cellular localization of APP and its interaction with various receptors is considered important. We here identify sortilin as a novel APP interaction partner. Like the related APP receptor SorLA, sortilin is highly expressed in the CNS, but whereas SorLA mainly colocalizes with APP in the soma, sortilin interacts with APP in neurites. The presence of sortilin promotes ?-secretase cleavage of APP, unlike SorLA, which inhibits the generation of all soluble products. Also, sortilin and SorLA both bind and mediate internalization of sAPP but to different cellular compartments. The interaction involves the 6A domain of APP, present in both neuronal and non-neuronal APP isoforms. This is important as sAPP receptors described so far only bind the non-neuronal isoforms, leaving SorLA and sortilin as the only receptors for sAPP generated by neurons. Together, our findings establish sortilin, as a novel APP interaction partner that influences both production and cellular uptake of sAPP.

Gustafsen, Camilla; Glerup, Simon

2013-01-01

319

Partial amino acid sequence of an amyloid fibril protein from nodular primary cutaneous amyloidosis showing homology to lambda immunoglobulin light chain of variable subgroup III (a lambda III).  

UK PubMed Central (United Kingdom)

An amyloid fibril protein (MA) was purified as a 17,000-dalton protein from a case of nodular primary cutaneous amyloidosis, and its partial amino acid sequence (22 residues from N-terminal) was determined. A sequence closely homologous to that of the lambda III subgroup of the immunoglobulin light chain was detected. This is the third case of nodular primary cutaneous amyloidosis which has been studied at the level of sequence analysis of purified amyloid fibril proteins, and the first case of nodular primary cutaneous amyloidosis in which a lambda III amyloid protein has been shown to be present by sequence analysis.

Kitajima Y; Hirata H; Kagawa Y; Yaoita H

1990-09-01

320

Light and electron microscopic localization of beta-amyloid protein in muscle biopsies of patients with inclusion-body myositis.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In 11 of 11 inclusion-body myositis (IBM) patients, including one hereditary case, vacuolated muscle fibers contained large and multiple small inclusions immunoreactive for beta-amyloid protein (beta AP). All IBM muscle biopsies had characteristic cytoplasmic tubulo-filaments (CTFs) by electron micr...

Askanas, V.; Engel, W. K.; Alvarez, R. B.

 
 
 
 
321

Multiple substitutions of methionine 129 in human prion protein reveal its importance in the amyloid fibrillation pathway  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The role of the polymorphism 129M/V in the human prion protein is well documented regarding disease susceptibility and clinical manifestations. Little is however known about the molecular background to this phenomenon. We herein investigated the conformational stability, amyloid fibrillation kinetic...

Nystrom, Sofie; Mishra, Rajesh; Hornemann, Simone; Aguzzi, Adriano; Nilsson, K Peter R; Hammarstrom, Per

322

Macroautophagy-generated increase of lysosomal amyloid ?-protein mediates oxidant-induced apoptosis of cultured neuroblastoma cells  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Increasing evidence suggests the toxicity of intracellular amyloid ?-protein (A?) to neurons, as well as the involvement of oxidative stress in Alzheimer disease (AD). Here we show that normobaric hyperoxia (exposure of cells to 40% oxygen for five days, and consequent activation of macroautophagy a...

Zheng, Lin; Terman, Alexi; Hallbeck, Martin; Dehvari, Nodi; Cowburn, Richard F.; Benedikz, Eirikur; Kågedal, Katarina

323

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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, fo...

Salkovic-Petrisic, M; Osmanovic, J; Grünblatt, E; Riederer, P; Hoyer, S

324

Protective effects of ferulic acid in amyloid precursor protein plus presenilin-1 transgenic mouse model of Alzheimer disease.  

UK PubMed Central (United Kingdom)

We previously reported the protective effects of long-term administration of ferulic acid against the in vivo toxicity of ?-amyloid peptide administered intracerebroventricularly in mice. In the present study, we investigated the effects of ferulic acid in transgenic amyloid precursor protein (APP)swe/presenilin 1 (PS1)dE9 (APP/PS1) mouse model of Alzheimer disease (AD). Chronic (for 6 months from the age of 6 to 12 months) oral administration of ferulic acid at a dose of 5.3?mg/kg/day significantly enhanced the performance in novel-object recognition task, and reduced amyloid deposition and interleukin-1 beta (IL-1?) levels in the frontal cortex. These results suggest that ferulic acid at a certain dosage could be useful for prevention and treatment of AD.

Yan JJ; Jung JS; Kim TK; Hasan A; Hong CW; Nam JS; Song DK

2013-01-01

325

Doped diamond-like carbon coatings for surgical instruments reduce protein and prion-amyloid biofouling and improve subsequent cleaning.  

UK PubMed Central (United Kingdom)

Doped diamond-like carbon (DLC) coatings offer potential antifouling surfaces against microbial and protein attachment. In particular, stainless steel surgical instruments are subject to tissue protein and resilient prion protein attachment, making decontamination methods used in sterile service departments ineffective, potentially increasing the risk of iatrogenic Creutzfeldt-Jakob disease during surgical procedures. This study examined the adsorption of proteins and prion-associated amyloid to doped DLC surfaces and the efficacy of commercial cleaning chemistries applied to these spiked surfaces, compared to titanium nitride coating and stainless steel. Surfaces inoculated with ME7-infected brain homogenate were visualised using SYPRO Ruby/Thioflavin T staining and modified epi-fluorescence microscopy before and after cleaning. Reduced protein and prion amyloid contamination was observed on the modified surfaces and subsequent decontamination efficacy improved. This highlights the potential for a new generation of coatings for surgical instruments to reduce the risk of iatrogenic CJD infection.

Secker TJ; Hervé R; Zhao Q; Borisenko KB; Abel EW; Keevil CW

2012-01-01

326

Serum amyloid A (SAA) as a biomarker of chronic infection due to boat strike trauma in a free-ranging Florida manatee (Trichechus manatus latirostris) with incidental polycystic kidneys  

Science.gov (United States)

Watercraft-related trauma is the predominant cause of human-induced mortality in manatees (Trichechus manatus latirostris), a federal- and state-listed endangered species. Pyothorax (documented in this case report) and other secondary infections are common sequelae of inhalation of water and the open wounds caused by boat propellers. These secondary infections can lead to the demise of the animal weeks to months after the traumatic incident when external wounds have healed. Diagnosis of underlying disease on physical examination during capture and restraint can be difficult. Acute phase proteins, including serum amyloid A, fibrinogen, and albumin can be used to diagnose inflammatory disease in manatees and improve quality of medical care and husbandry. We also provide the first report of polycystic kidneys in Sirenians.

Harr, Kendal E.; Rember, Renee; Ginn, Pamela E.; Lightsey, Jessica; Keller, Martha; Reid, James; Bonde, Robert K.

2011-01-01

327

Serum amyloid A (SAA) as a biomarker of chronic infection due to boat strike trauma in a free-ranging Florida manatee (Trichechus manatus latirostris) with incidental polycystic kidneys.  

UK PubMed Central (United Kingdom)

Watercraft-related trauma is the predominant cause of human-induced mortality in manatees (Trichechus manatus latirostris), a federal- and state-listed endangered species. Pyothorax (documented in this case report) and other secondary infections are common sequelae of inhalation of water and the open wounds caused by boat propellers. These secondary infections can lead to the demise of the animal weeks to months after the traumatic incident when external wounds have healed. Diagnosis of underlying disease on physical examination during capture and restraint can be difficult. Acute phase proteins, including serum amyloid A, fibrinogen, and albumin can be used to diagnose inflammatory disease in manatees and improve quality of medical care and husbandry. We also provide the first report of polycystic kidneys in Sirenians.

Harr KE; Rember R; Ginn PE; Lightsey J; Keller M; Reid J; Bonde RK

2011-10-01

328

Serum amyloid A level is increased in neuromyelitis optica and atypical multiple sclerosis with smaller T2 lesion volume in brain MRI.  

UK PubMed Central (United Kingdom)

Serum amyloid A (SAA) is known to promote the development of T helper 17 cells (Th17) and can be a critical mediator of disease pathogenesis. We analyzed SAA levels in 40 patients with multiple sclerosis (MS) and related disorders, and 10 with non-inflammatory neurological disease (NIND) as controls. We found that SAA levels were significantly increased in neuromyelitis optica (NMO) patients and relapsing and remitting MS (RRMS) patients showing atypical phenotype with spinal cord lesions and smaller T2 lesion volume in brain MRI, resembling NMO. Therefore, SAA levels can be associated with clinical phenotypes in MS and NMO.

Yokote H; Yagi Y; Watanabe Y; Amino T; Kamata T; Mizusawa H

2013-06-01

329

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

UK PubMed Central (United Kingdom)

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.-Sosa, L. J., Postma, N. L., Estrada-Bernal, A., Hanna, M., Guo, R., Busciglio, J., Pfenninger, K. H. Dosage of amyloid precursor protein affects axonal contact guidance in Down syndrome.

Sosa LJ; Postma NL; Estrada-Bernal A; Hanna M; Guo R; Busciglio J; Pfenninger KH

2013-09-01

330

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 (PrPC) 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 PrPC. The binding of A? oligomers to cell surface PrPC, 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 PrPC, 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 PrPC 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 PrPC-expressing cells and were no longer cytotoxic. These data indicate that soluble, fibrillar A? oligomers bind to PrPC 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.

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

2013-01-01

331

Dual roles of the transmembrane protein p23/TMP21 in the modulation of amyloid precursor protein metabolism  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Alzheimer's disease (AD) is characterized by cerebral deposition of ?-amyloid (A?) peptides. A? is released from ectodomain cleaved amyloid precursor protein (APP) via intramembranous proteolysis by ?-secretase, a complex consisting of presenilin and a few other proteins. p23/TMP21, a member of the p24 family type I transmembrane proteins, was recently identified as a presenilin complex component capable of modulating ?-secretase cleavage. The p24 family proteins form oligomeric complexes and regulate vesicular trafficking in the early secretory pathway, but their role in APP trafficking has not been investigated. Results Here, we report that siRNA-mediated depletion of p23 in N2a neuroblastoma and HeLa cells produces concomitant knockdown of additional p24 family proteins and increases secretion of sAPP. Furthermore, intact cell and cell-free A? production increases following p23 knockdown, similar to data reported earlier using HEK293 cells. However, we find that p23 is not present in mature ?-secretase complexes isolated using an active-site ?-secretase inhibitor. Depletion of p23 and expression of a familial AD-linked PS1 mutant have additive effects on A?42 production. Knockdown of p23 expression confers biosynthetic stability to nascent APP, allowing its efficient maturation and surface accumulation. Moreover, immunoisolation analyses show decrease in co-residence of APP and the APP adaptor Mint3. Thus, multiple lines of evidence indicate that p23 function influences APP trafficking and sAPP release independent of its reported role in ?-secretase modulation. Conclusion These data assign significance to p24 family proteins in regulating APP trafficking in the continuum of bidirectional transport between the ER and Golgi, and ascribe new relevance to the regulation of early trafficking in AD pathogenesis.

Vetrivel Kulandaivelu S; Gong Ping; Bowen James W; Cheng Haipeng; Chen Ying; Carter Meghan; Nguyen Phuong D; Placanica Lisa; Wieland Felix T; Li Yue-Ming; Kounnas Maria Z; Thinakaran Gopal

2007-01-01

332

Fc?RI mediates serum amyloid P inhibition of fibrocyte differentiation.  

UK PubMed Central (United Kingdom)

Fibrotic diseases, such as cardiac and pulmonary fibrosis, have a poor prognosis with no FDA approved therapies. Monocyte-derived, fibroblast-like cells, called fibrocytes, participate in the formation of fibrotic lesions. The conserved pentraxin protein SAP inhibits fibrocyte differentiation in cell culture, and injections of SAP significantly reduce fibrosis in several animal models. SAP binds to the receptors for the Fc portion of IgG (Fc?R) and has been crystallized bound to Fc?RIIa (CD32a). The in vivo activity of SAP appears to be dependent on the FcR?. We find that mutagenesis of the residues critical for SAP binding to Fc?RIIa only moderately decreases the ability of SAP to inhibit fibrocyte differentiation. In murine cells, deletion of FcR? or Fc?RI (CD64) significantly reduced sensitivity to SAP. Deletion of the combination of Fc?RIIb, Fc?RIIIa, and Fc?RIV did not significantly affect sensitivity to SAP, whereas deletion of just the inhibitory receptor Fc?RIIb (CD32b) increased sensitivity to SAP. In human cells, siRNA-mediated reduction of FcR? or Fc?RI levels significantly decreased sensitivity to SAP, whereas reduction of Fc?RIIb levels increased sensitivity to SAP. These observations suggest that SAP, at least in part, uses Fc?RI and FcR? to inhibit fibrocyte differentiation.

Crawford JR; Pilling D; Gomer RH

2012-10-01

333

Substitution of membrane cholesterol with ?-sitosterol promotes nonamyloidogenic cleavage of endogenous amyloid precursor protein.  

UK PubMed Central (United Kingdom)

Increasing evidence has linked membrane cholesterol to amyloid precursor protein (APP) processing. ?-Sitosterol (BS) is one of the most common forms of plant sterols, with the structure very similar to that of cholesterol. Using HT22 mouse hippocampal cells, this study investigated whether the substitution of membrane cholesterol with BS influences APP metabolism. It was found that cholesterol/BS substitution promoted nonamyloidogenic processing of APP without affecting membrane fluidity. Additional experiments suggest that the effect of membrane BS on APP metabolism is associated with the migration of APP from lipid rafts toward non-raft regions. Given that dietary BS can enter the brain and accumulates in the plasma membrane of brain cells, these results suggest a potential use of BS in the prevention of Alzheimer's disease.

Wang J; Wu F; Shi C

2013-09-01

334

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; Kågedal, Katarina

2009-01-01

335

Characterization of high-affinity binding between gangliosides and amyloid beta-protein.  

Science.gov (United States)

The binding specificities of amyloid beta-protein (A beta) such as A beta 1-40, A beta 1-42, A beta 40-1, A beta 1-38, A beta 25-35, and amyloid beta precursor protein (beta-APP) analogues for different glycosphingolipids were determined by surface plasmon resonance (SPR) using a liposome capture method. A beta 1-42, A beta 1-40, A beta 40-1, and A beta 1-38, but not A beta 25-35, bound to GM1 ganglioside in the following rank order: A beta 1-42 > A beta 40-1 > A beta 1-40 > A beta 1-38. The beta-APP analogues bound to GM1 ganglioside with a relatively lower affinity. Aged derivatives of A beta were found to have higher affinity to GM1 ganglioside than fresh or soluble derivatives. A beta 1-40 bound to a number of gangliosides with the following order of binding strength: GQ1b alpha > GT1a alpha > GQ1b > GT1b > GD3 > GD1a = GD1b > LM1 > GM1 > GM2 = GM3 > GM4. Neutral glycosphingolipids had a lower affinity for A beta 1-40 than gangliosides with the following order of binding strength: Gb4 > asialo-GM1 (GA1) > Gb3 > asialo-GM2 (GA2) = LacCer. The results seem to indicate that an alpha2,3NeuAc residue on the neutral oligosaccharide core is required for binding. In addition, the alpha2-6NeuAc residue linked to GalNAc contributes significantly to binding affinity for A beta. PMID:11368158

Ariga, T; Kobayashi, K; Hasegawa, A; Kiso, M; Ishida, H; Miyatake, T

2001-04-15

336

Palmitoylation of amyloid precursor protein regulates amyloidogenic processing in lipid rafts.  

UK PubMed Central (United Kingdom)

Brains of patients affected by Alzheimer's disease (AD) contain large deposits of aggregated amyloid ?-protein (A?). Only a small fraction of the amyloid precursor protein (APP) gives rise to A?. Here, we report that ?10% of APP undergoes a post-translational lipid modification called palmitoylation. We identified the palmitoylation sites in APP at Cys¹?? and Cys¹??. Surprisingly, point mutations introduced into these cysteines caused nearly complete ER retention of APP. Thus, either APP palmitoylation or disulfide bridges involving these Cys residues appear to be required for ER exit of APP. In later compartments, palmitoylated APP (palAPP) was specifically enriched in lipid rafts. In vitro BACE1 cleavage assays using cell or mouse brain lipid rafts showed that APP palmitoylation enhanced BACE1-mediated processing of APP. Interestingly, we detected an age-dependent increase in endogenous mouse brain palAPP levels. Overexpression of selected DHHC palmitoyl acyltransferases increased palmitoylation of APP and doubled A? production, while two palmitoylation inhibitors reduced palAPP levels and APP processing. We have found previously that acyl-coenzyme A:cholesterol acyltransferase (ACAT) inhibition led to impaired APP processing. Here we demonstrate that pharmacological inhibition or genetic inactivation of ACAT decrease lipid raft palAPP levels by up to 76%, likely resulting in impaired APP processing. Together, our results indicate that APP palmitoylation enhances amyloidogenic processing by targeting APP to lipid rafts and enhancing its BACE1-mediated cleavage. Thus, inhibition of palAPP formation by ACAT or specific palmitoylation inhibitors would appear to be a valid strategy for prevention and/or treatment of AD.

Bhattacharyya R; Barren C; Kovacs DM

2013-07-01

337

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

338

Amyloid fibrils composed of hexameric peptides attenuate neuroinflammation.  

UK PubMed Central (United Kingdom)

The amyloid-forming proteins tau, ?B crystallin, and amyloid P protein are all found in lesions of multiple sclerosis (MS). Our previous work established that amyloidogenic peptides from the small heat shock protein ?B crystallin (HspB5) and from amyloid ? fibrils, characteristic of Alzheimer's disease, were therapeutic in experimental autoimmune encephalomyelitis (EAE), reflecting aspects of the pathology of MS. To understand the molecular basis for the therapeutic effect, we showed a set of amyloidogenic peptides composed of six amino acids, including those from tau, amyloid ? A4, major prion protein (PrP), HspB5, amylin, serum amyloid P, and insulin B chain, to be anti-inflammatory and capable of reducing serological levels of interleukin-6 and attenuating paralysis in EAE. The chaperone function of the fibrils correlates with the therapeutic outcome. Fibrils composed of tau 623-628 precipitated 49 plasma proteins, including apolipoprotein B-100, clusterin, transthyretin, and complement C3, supporting the hypothesis that the fibrils are active biological agents. Amyloid fibrils thus may provide benefit in MS and other neuroinflammatory disorders.

Kurnellas MP; Adams CM; Sobel RA; Steinman L; Rothbard JB

2013-04-01

339

Amyloid core formed of full-length recombinant mouse prion protein involves sequence 127-143 but not sequence 107-126.  

UK PubMed Central (United Kingdom)

The principal event underlying the development of prion disease is the conversion of soluble cellular prion protein (PrP(C)) into its disease-causing isoform, PrP(Sc). This conversion is associated with a marked change in secondary structure from predominantly ?-helical to a high ?-sheet content, ultimately leading to the formation of aggregates consisting of ordered fibrillar assemblies referred to as amyloid. In vitro, recombinant prion proteins and short prion peptides from various species have been shown to form amyloid under various conditions and it has been proposed that, theoretically, any protein and peptide could form amyloid under appropriate conditions. To identify the peptide segment involved in the amyloid core formed from recombinant full-length mouse prion protein mPrP(23-230), we carried out seed-induced amyloid formation from recombinant prion protein in the presence of seeds generated from the short prion peptides mPrP(107-143), mPrP(107-126), and mPrP(127-143). Our results showed that the amyloid fibrils formed from mPrP(107-143) and mPrP(127-143), but not those formed from mPrP(107-126), were able to seed the amyloidogenesis of mPrP(23-230), showing that the segment residing in sequence 127-143 was used to form the amyloid core in the fibrillization of mPrP(23-230).

Chatterjee B; Lee CY; Lin C; Chen EH; Huang CL; Yang CC; Chen RP

2013-01-01

340

Amyloid fibril formation by lens crystallin proteins and its implications for cataract formation.  

UK PubMed Central (United Kingdom)

The alpha-, beta-, and gamma-crystallins are the major structural proteins within the eye lens and are responsible for its exceptional stability and transparency. Under mildly denaturing conditions, all three types of bovine crystallin assemble into fibrillar structures in vitro. Characterization by transmission electron microscopy, dye binding assays, and x-ray fiber diffraction shows that these species have all of the characteristics of fibrils associated with the family of amyloid diseases. Moreover, the full-length proteins are incorporated into the fibrils, (i.e. no protein cleavage is required for these species to form), although for the gamma-crystallins some fragmentation occurs under the conditions employed in this study. Our findings indicate that the inherent stability of the beta-sheet supramolecular structure adopted by the crystallins in the eye lens and the chaperone ability of alpha-crystallin must be crucial for preventing fibril formation in vivo. The crystallins are very stable proteins but undergo extensive post-translational modification with age that leads to their destabilization. The ability of the crystallins to convert into fibrils under destabilizing conditions suggests that this process could contribute to the development of cataract with aging.

Meehan S; Berry Y; Luisi B; Dobson CM; Carver JA; MacPhee CE

2004-01-01

 
 
 
 
341

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

342

Binding of an oxindole alkaloid from Uncaria tomentosa to amyloid protein (Abeta1-40).  

UK PubMed Central (United Kingdom)

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.

Frackowiak T; Baczek T; Roman K; Zbikowska B; Gle?sk M; Fecka I; Cisowski W

2006-11-01

343

Control the aggregation of model amyloid insulin protein under ac-electric fields  

Science.gov (United States)

In vitro experiments have been widely used to characterize the misfolding/unfolding pathway characteristic of amylodogenic proteins. Conversion from natively folded amyloidogenic proteins to oligomers via nucleation is the accepted path to fibril formation upon heating over a certain lag time period. In an alternative engineering approach to manipulate and control protein aggregation, we have investigated the aggregation kinetics of insulin, a well-established amyloid model protein, under applied ac-electric fields of varied ac-frequency and voltage at room temperature. Using fluorescence correlation spectroscopy and fluorescence imaging, we have observed that the insulin aggregation can occur at much shortened lag time under applied ac-electric fields, when a critical ac-voltage is exceeded. The strong dependence of lag time on ac-frequency over a narrow range of 500 Hz-5 kHz indicates the effect of ac-electroosmosis on the diffusion controlled process of insulin nucleation. Yet, no difference of conformational structure is detected with insulin under applied ac-fields, suggesting the equivalence of ac-polarization to the conventional thermal activation process for insulin aggregation.

Zheng, Zhongli; Jing, Benxin; Zhu, Y. Elaine

2013-03-01

344

PPAR?/RXR?-induced and CD36-mediated microglial amyloid-? phagocytosis results in cognitive improvement in amyloid precursor protein/presenilin 1 mice.  

Science.gov (United States)

Alzheimer's disease (AD) is characterized by the extracellular deposition of amyloid-? (A?), neurofibrillary tangle formation, and a microglial-driven inflammatory response. Chronic inflammatory activation compromises microglial clearance functions. Because peroxisome proliferator-activated receptor ? (PPAR?) agonists suppress inflammatory gene expression, we tested whether activation of PPAR? would also result in improved microglial A? phagocytosis. The PPAR? agonist pioglitazone and a novel selective PPAR?/? modulator, DSP-8658, currently in clinical development for the treatment of type 2 diabetes, enhanced the microglial uptake of A? in a PPAR?-dependent manner. This PPAR?-stimulated increase of A? phagocytosis was mediated by the upregulation of scavenger receptor CD36 expression. In addition, combined treatment with agonists for the heterodimeric binding partners of PPAR?, the retinoid X receptors (RXRs), showed additive enhancement of the A? uptake that was mediated by RXR? activation. Evaluation of DSP-8658 in the amyloid precursor protein/presenilin 1 mouse model confirmed an increased microglial A? phagocytosis in vivo, which subsequently resulted in a reduction of cortical and hippocampal A? levels. Furthermore, DSP-8658-treated mice showed improved spatial memory performance. Therefore, stimulation of microglial clearance by simultaneous activation of the PPAR?/RXR? heterodimer may prove beneficial in prevention of AD. PMID:23197723

Yamanaka, Mitsugu; Ishikawa, Taizo; Griep, Angelika; Axt, Daisy; Kummer, Markus P; Heneka, Michael T

2012-11-28

345

PPAR?/RXR?-induced and CD36-mediated microglial amyloid-? phagocytosis results in cognitive improvement in amyloid precursor protein/presenilin 1 mice.  

UK PubMed Central (United Kingdom)

Alzheimer's disease (AD) is characterized by the extracellular deposition of amyloid-? (A?), neurofibrillary tangle formation, and a microglial-driven inflammatory response. Chronic inflammatory activation compromises microglial clearance functions. Because peroxisome proliferator-activated receptor ? (PPAR?) agonists suppress inflammatory gene expression, we tested whether activation of PPAR? would also result in improved microglial A? phagocytosis. The PPAR? agonist pioglitazone and a novel selective PPAR?/? modulator, DSP-8658, currently in clinical development for the treatment of type 2 diabetes, enhanced the microglial uptake of A? in a PPAR?-dependent manner. This PPAR?-stimulated increase of A? phagocytosis was mediated by the upregulation of scavenger receptor CD36 expression. In addition, combined treatment with agonists for the heterodimeric binding partners of PPAR?, the retinoid X receptors (RXRs), showed additive enhancement of the A? uptake that was mediated by RXR? activation. Evaluation of DSP-8658 in the amyloid precursor protein/presenilin 1 mouse model confirmed an increased microglial A? phagocytosis in vivo, which subsequently resulted in a reduction of cortical and hippocampal A? levels. Furthermore, DSP-8658-treated mice showed improved spatial memory performance. Therefore, stimulation of microglial clearance by simultaneous activation of the PPAR?/RXR? heterodimer may prove beneficial in prevention of AD.

Yamanaka M; Ishikawa T; Griep A; Axt D; Kummer MP; Heneka MT

2012-11-01

346

The conserved TFLK motif of mammary-associated serum amyloid A3 is responsible for up-regulation of intestinal MUC3 mucin expression in vitro.  

Science.gov (United States)

In various mammalian species, an isoform of serum amyloid A is secreted at high concentrations into colostrum. A conserved four-amino-acid motif (TFLK) is contained within the first eight N-terminal amino acid residues of this mammary-associated serum amyloid A isoform 3 (M-SAA3). Peptides derived from the bovine N-terminal amino acid sequence of M-SAA3 were produced and added to cell culture medium of HT29 cells to study the effects on intestinal mucin gene expression. HT29 cells were grown to enhance expression of either MUC2 or MUC3 intestinal mucins. After incubation, total RNA was isolated for Northern blot analyses using MUC2 or MUC3 mucin cDNA probes. Signals were detected by autoradiography with mRNA levels expressed relative to 28S rRNA. The 10-mer peptides containing the intact TFLK-motif or a TFLK 4-mer peptide increased MUC3 mRNA expression compared with control cells (p E2348/69 adhesion to HT29 cells grown to enhance MUC3 expression was reduced by a similar amount when either peptides containing the intact TFLK motif or probiotic microbes were added to cell culture medium compared with control cells. M-SAA3 is a bioactive peptide secreted into colostrums that can up-regulate mucin expression and thereby may enhance innate protective mechanisms that limit access of deleterious microbes to intestinal mucosal epithelial cells in the postparturition period. PMID:12508093

Mack, David R; McDonald, Thomas L; Larson, Marilynn A; Wei, Shu; Weber, Annika

2003-01-01

347

Spectroscopic imaging of serum proteins using quantum cascade lasers.  

UK PubMed Central (United Kingdom)

First measurements of biomedical imaging using quantum cascade lasers (QCL) are presented. We report spectroscopic imaging of serum proteins using QCLs as an example for monitoring surface biocontamination. We found that dry smears of human serum can be spectroscopically imaged, identified, and quantified with high sensitivity and specificity. The core parts of the imaging platform consist of optically multiplexing three QCLs and an uncooled microbolometer camera. We show imaging of human serum proteins at 6.1, 9.25, and 9.5 ?m QCLs with high sensitivity and specificity. The sensitivity limit of 3???g/cm² of the human serum spot was measured at an S/N=3.The specificity of human serum detection was measured at 99% probability at a threshold of 77???g/cm². We anticipate our imaging technique to be a starting point for more sophisticated biomolecular diagnostic applications.

Mukherjee A; Bylund Q; Prasanna M; Margalit Y; Tihan T

2013-03-01

348

Human serum lipoproteins influence protein deposition patterns on nanoparticle surfaces.  

UK PubMed Central (United Kingdom)

We report the concentration-dependent adsorption of serum lipoproteins onto silica nanoparticles, wherein elevated lipid levels deter complement activation. Two clinically relevant serum lipid levels - corresponding to low and borderline high levels in normal, healthy adults - were used to examine the influence of lipoprotein concentration on nanoparticle complement activation. Human serum albumin was used to study protein adsorption in the presence of lipoproteins. Preferential adsorption of high affinity lipoproteins led to greater lipid fractions in the protein corona, shielding particles from complement activation. These findings have significant implications for the design of intravenously administered carriers with biocompatible surface chemistries.

Meerasa A; Huang JG; Gu FX

2013-02-01

349

Association of the carboxy-terminus of beta-amyloid protein precursor with Alzheimer paired helical filaments.  

Science.gov (United States)

We investigated whether a peptide fragment from the C-terminus of beta-amyloid protein precursor is associated with Alzheimer paired helical filaments (PHFs). Antiserum BR188, to the last 20 amino acids of the precursor, did not cross-react with tau protein, known to be in PHFs. It did react with all five pronase-treated PHF preparations assayed by ELISA and immunogold-labelled the same PHF fibrils that a PHF-specific tau antibody labelled. Neither antibody labelled beta/A4 fibrils. These results suggest that a fragment from the C-terminus of beta-amyloid precursor protein copurifies with pronase-treated PHFs and may play a role in their molecular pathogenesis. PMID:1627127

Caputo, C B; Sobel, I R; Scott, C W; Brunner, W F; Barth, P T; Blowers, D P

1992-06-30

350

Minocycline alleviates beta-amyloid protein and tau pathology via restraining neuroinflammation induced by diabetic metabolic disorder  

Directory of Open Access Journals (Sweden)

Full Text Available Zhiyou Cai,1 Yong Yan,2 Yonglong Wang2 1Department of Neurology, the Lu’an Affiliated Hospital of Anhui Medical University, Lu’an People’s Hospital, Lu’an, Anhui Province, People’s Republic of China; 2Department of Neurology, the First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, People’s Republic of China Background: Compelling evidence has shown that diabetic metabolic disorder plays a critical role in the pathogenesis of Alzheimer’s disease, including increased expression of ?-amyloid protein (A?) and tau protein. Evidence has supported that minocycline, a tetracycline derivative, protects against neuroinflammation induced by neurodegenerative disorders or cerebral ischemia. This study has evaluated minocycline influence on expression of A? protein, tau phosphorylation, and inflammatory cytokines (interleukin-1? and tumor necrosis factor-?) in the brain of diabetic rats to clarify neuroprotection by minocycline under diabetic metabolic disorder. Method: An animal model of diabetes was established by high fat diet and intraperitoneal injection of streptozocin. In this study, we investigated the effect of minocycline on expression of A? protein, tau phosphorylation, and inflammatory cytokines (interleukin-1? and tumor necrosis factor-?) in the hippocampus of diabetic rats via immunohistochemistry, western blotting, and enzyme-linked immunosorbent assay. Results: These results showed that minocycline decreased expression of A? protein and lowered the phosphorylation of tau protein, and retarded the proinflammatory cytokines, but not amyloid precursor protein. Conclusion: On the basis of the finding that minocycline had no influence on amyloid precursor protein and beta-site amyloid precursor protein cleaving enzyme 1 which determines the speed of A? generation, the decreases in A? production and tau hyperphosphorylation by minocycline are through inhibiting neuroinflammation, which contributes to A? production and tau hyperphosphorylation. Minocycline may also lower the self-perpetuating cycle between neuroinflammation and the pathogenesis of tau and A? to act as a neuroprotector. Therefore, the ability of minocycline to modulate inflammatory reactions may be of great importance in the selection of neuroprotective agents, especially in chronic conditions like diabetes and Alzheimer’s disease. Keywords: diabetes mellitus, minocycline, tau protein, ?-amyloid protein

Cai Z; Yan Y; Wang Y

2013-01-01

351

Effects of oxidative stress on amyloid precursor protein processing in rat and human platelets.  

UK PubMed Central (United Kingdom)

Alzheimer's disease (AD) is the most common neurodegenerative illness affecting the elderly and is characterized by beta-amyloid (A?) deposition in the brain (plaques) and in microvessels (A?-angiopathy). The reasons for A? deposition are not clear, but an impaired clearance of A? at the blood-brain barrier may be implicated and oxidative stress possibly plays a major role in this process. Platelets are of particular interest, because they contain high levels of the amyloid precursor protein (APP) and in AD an abnormal expression of platelets APP fragments was found. The aim of the present study was to investigate (1) if oxidative stress induced by hydrogen peroxide (H(2)O(2)) affects APP expression in rat and human platelets and (2) to compare the APP changes with platelets of AD patients. In rat platelets, all three fragments of APP (130-110-106 kilo Dalton, kDa) were found. H(2)O(2) (10 mM, 20 minutes) significantly reduced all three fragments in rat platelets, did not affect CD62P-staining and slightly increased the size of actin as seen in the Western blot. The effect was not seen at 1 mM H(2)O(2) and was counteracted by glutathione. Immunohistochemistry for CD62P, CD61, APP and Annexin-V was used to verify the changes at the cellular level. In platelets of young volunteers (age = 33 ± 4 years), 10 mM H(2)O(2) markedly reduced the smaller APP 110 and 106 kDa fragments after 20 minutes. Our data show that platelets of AD patients (age = 80 ± 1 years) had a significant reduced 130 kDa fragment compared to controls (age = 70 ± 2 years). In summary, oxidative stress may account for a dysfunctional processing of APP in rat and human control platelets and possibly in AD patients.

Ehrlich D; Hochstrasser T; Humpel C

2013-01-01

352

NeuroAiD® (MLC601) and amyloid precursor protein processing.  

UK PubMed Central (United Kingdom)

BACKGROUND: Amyloid precursor protein (APP) undergoes cleavage under physiological conditions, predominantly by ?- and ?-secretases, to form the nonpathogenic sAPP? and p3 fragments. By contrast, amyloid-beta (A?) is produced via proteolytic cleavage by ?- and ?-secretases. In Alzheimer's disease (AD), APP is preferentially processed via the amyloidogenic pathway, producing large amounts of A? that form the major constituent of senile plaques and tau-containing neurofibrillary tangles. Similarly, stroke patients have a higher level of A? around the area of infarct, suggesting that A? may mediate at least some of the secondary neurotoxicity observed in stroke patients. METHODS: To investigate the effects of MLC601 (NeuroAiD(®)) on regulation of APP processing, the human neuroblastoma cell line SH-SY5Y was used for all experiments. Stocks of MLC601 were prepared at a final concentration of 50 mg/ml. Cells were treated with different concentrations of MLC601 before assessing changes in the levels of released lactate dehydrogenase (LDH), full-length APP and secreted sAPP?. RESULTS: Concentrations of MLC601 between 1 and 1,000 µg/ml significantly lowered the levels of LDH released into the media when compared to control cells. In contrast, MLC601 concentrations at 5,000 and 10,000 µg/ml resulted in a significant increase in the LDH release. Treatment with 100, 500 and 1,000 ?g/ml of MLC601 significantly increases the levels of sAPP? secreted by SH-SY5Y into the media. Treatment with 1,000 ?g/ml of MLC601 significantly decreased the levels of full-length APP. CONCLUSION: MLC601 is a possible modulator of APP processing and has implications as a putative therapeutic strategy for the treatment of poststroke dementia and AD.

Lim YA; Murray LA; Lai MK; Chen C

2013-01-01

353

Phosphorylation-induced structural changes in the amyloid precursor protein cytoplasmic tail detected by NMR.  

UK PubMed Central (United Kingdom)

The cytoplasmic tail of the amyloid precursor protein (APPc) interacts with several cellular factors implicated in intracellular signaling or proteolytic production of amyloid beta peptide found in senile plaques of Alzheimer's disease patients. APPc contains two threonine residues (654 and 668 relative to APP695, or 6 and 20 relative to APPc) and a serine residue (655 or 7, respectively) that are known to be phosphorylated in vivo and may play regulatory roles in these events. We show by solution NMR spectroscopy of a 49 residue cytoplasmic tail peptide (APP-C) that in all three cases, phosphorylation induces changes in backbone dihedral angles that can be attributed to formation of local hydrogen bonds between the phosphate group and nearby amide protons. Phosphorylation of S7 also induces chemical shift changes in the hydrophobic cluster (residues I8-V13), indicating additional medium-range effects. The most pronounced changes occur upon phosphorylation of T20, a neuron-specific phosphorylation site, where the N-terminal helix capping box previously characterized for this region is altered. Characterization of torsion angles and transient hydrogen bonds indicates that prolyl isomerization of the pThr-Pro peptide bond results from both destabilization of the N-terminal helix capping box and stabilization of the cis isomer by transient hydrogen bonds. The significant population of the cis isomer (9 %) present after phosphorylation of T20 suggests a potential role of selective recognition of cis versus trans isomers in response to phosphorylation of APP. Together, these structural changes indicate that phosphorylation may act as a conformational switch in the cytoplasmic tail of APP to alter specificity and affinity of binding to cytosolic partners, particularly in response to the abnormal phosphorylation events associated with Alzheimer's disease.

Ramelot TA; Nicholson LK

2001-03-01

354

Amyloid-? protein modulates the perivascular clearance of neuronal apolipoprotein E in mouse models of Alzheimer's disease.  

UK PubMed Central (United Kingdom)

The deposition of amyloid-? protein (A?) in the brain is a hallmark of Alzheimer's disease (AD). Apolipoprotein E (apoE) is involved in the clearance of A? from brain and the APOE ?4 allele is a major risk factor for sporadic AD. We have recently shown that apoE is drained into the perivascular space (PVS), where it co-localizes with A?. To further clarify the role of apoE in perivascular clearance of A?, we studied apoE-transgenic mice over-expressing human apoE4 either in astrocytes (GE4) or in neurons (TE4). These animals were crossbred with amyloid precursor protein (APP)-transgenic mice and with APP-presenilin-1 (APP-PS1) double transgenic mice. Using an antibody that specifically detects human apoE (h-apoE), we observed that astroglial expression of h-apoE in GE4 mice leads to its perivascular drainage, whereas neuronal expression in TE4 mice does not, indicating that neuron-derived apoE is usually not the subject of perivascular drainage. However, h-apoE was observed not only in the PVS of APP-GE4 and APP-PS1-GE4 mice, but also in that of APP-TE4 and APP-PS1-TE4 mice. In all these mouse lines, we found co-localization of neuron-derived h-apoE and A? in the PVS. A? and h-apoE were also found in the cytoplasm of perivascular astrocytes indicating that astrocytes take up the neuron-derived apoE bound to A?, presumably prior to its clearance into the PVS. The uptake of apoE-A? complexes into glial cells was further investigated in glioblastoma cells. It was mediated by ?(2)macroglobulin receptor/low density lipoprotein receptor-related protein (LRP-1) and inhibited by adding receptor-associated protein (RAP). It results in endosomal A? accumulation within these cells. These results suggest that neuronal apoE-A? complexes, but not neuronal apoE alone, are substrates for LRP-1-mediated astroglial uptake, transcytosis, and subsequent perivascular drainage. Thus, the production of A? and its interaction with apoE lead to the pathological perivascular drainage of neuronal apoE and provide insight into the pathological interactions of A? with neuronal apoE metabolism.

Rolyan H; Feike AC; Upadhaya AR; Waha A; Van Dooren T; Haass C; Birkenmeier G; Pietrzik CU; Van Leuven F; Thal DR

2011-05-01

355

Drosophila amyloid precursor protein-like is required for long-term memory.  

UK PubMed Central (United Kingdom)

The amyloid precursor protein (APP) plays an important role in Alzheimer's disease (AD), a progressive neurodegenerative pathology that first manifests as a decline of memory. While the main hypothesis for AD pathology centers on the proteolytic processing of APP, very little is known about the physiological function of the APP protein in the adult brain. Likewise, whether APP loss of function contributes to AD remains unclear. Drosophila has been used extensively as a model organism to study neuronal function and pathology. In addition, many of the molecular mechanisms underlying memory are thought to be conserved from flies to mammals, prompting us to study the function of APPL, the fly APP ortholog, during associative memory. It was previously shown that APPL expression is highly enriched in the mushroom bodies (MBs), a specialized brain structure involved in olfactory memory. We analyzed memory in flies in which APPL expression has been silenced specifically and transiently in the adult MBs. Our results show that in adult flies, APPL is not required for learning but is specifically involved in long-term memory, a long lasting memory whose formation requires de novo protein synthesis and is thought to require synaptic structural plasticity. These data support the hypothesis that disruption of normal APP function may contribute to early AD cognitive impairment.

Goguel V; Belair AL; Ayaz D; Lampin-Saint-Amaux A; Scaplehorn N; Hassan BA; Preat T

2011-01-01

356

Presynaptic and postsynaptic interaction of the amyloid precursor protein promotes peripheral and central synaptogenesis.  

UK PubMed Central (United Kingdom)

A critical role of the amyloid precursor protein (APP) in Alzheimer's disease (AD) pathogenesis has been well established. However, the physiological function of APP remains elusive and much debated. We reported previously that the APP family of proteins is essential in mediating the developing neuromuscular synapse. In the current study, we created a conditional allele of APP and deleted APP in presynaptic motor neuron or postsynaptic muscle. Crossing these alleles onto the APP-like protein 2-null background reveals that, unexpectedly, inactivating APP in either compartment results in neuromuscular synapse defects similar to the germline deletion and that postsynaptic APP is obligatory for presynaptic targeting of the high-affinity choline transporter and synaptic transmission. Using a HEK293 and primary hippocampus mixed-culture assay, we report that expression of APP in HEK293 cells potently promotes synaptogenesis in contacting axons. This activity is dependent on neuronal APP and requires both the extracellular and intracellular domains; the latter forms a complex with Mint1 and Cask and is replaceable by the corresponding SynCAM (synaptic cell adhesion molecule) sequences. These in vitro and in vivo studies identify APP as a novel synaptic adhesion molecule. We postulate that transsynaptic APP interaction modulates its synaptic function and that perturbed APP synaptic adhesion activity may contribute to synaptic dysfunction and AD pathogenesis.

Wang Z; Wang B; Yang L; Guo Q; Aithmitti N; Songyang Z; Zheng H

2009-09-01

357

Mechanism of cytotoxicity mediated by the C31 fragment of the amyloid precursor protein.  

Science.gov (United States)

The cytoplasmic tail of the amyloid precursor protein (APP) contains two putatively cytotoxic peptides, Jcasp and C31, derived by caspase cleavage of APP. Jcasp is a fragment starting from the epsilon-secretase site to position 664, while C31 is a fragment from position 665 to the C-terminus. Our studies now showed that compared to C31, Jcasp appeared to play a minor role in cytotoxicity. In particular, inhibition of Jcasp generation by treatment of gamma-secretase inhibitor did not lead to any attenuation of C31-induced toxicity. Secondly, because C31 toxicity is largely absent in cells lacking endogenous APP, we determined, using a split beta-galactosidase complementary assay to monitor protein-protein interactions, the presence of APP associated complexes. Our results demonstrated that both APP homomeric and C31/APP heteromeric complexes were correlated with cell death, indicating that C31 complexes with APP to recruit the interacting partners that initiate the signals related to cellular toxicity. PMID:19679105

Park, Sun Ah; Shaked, Gideon M; Bredesen, Dale E; Koo, Edward H

2009-08-11

358

Mechanism of cytotoxicity mediated by the C31 fragment of the amyloid precursor protein.  

UK PubMed Central (United Kingdom)

The cytoplasmic tail of the amyloid precursor protein (APP) contains two putatively cytotoxic peptides, Jcasp and C31, derived by caspase cleavage of APP. Jcasp is a fragment starting from the epsilon-secretase site to position 664, while C31 is a fragment from position 665 to the C-terminus. Our studies now showed that compared to C31, Jcasp appeared to play a minor role in cytotoxicity. In particular, inhibition of Jcasp generation by treatment of gamma-secretase inhibitor did not lead to any attenuation of C31-induced toxicity. Secondly, because C31 toxicity is largely absent in cells lacking endogenous APP, we determined, using a split beta-galactosidase complementary assay to monitor protein-protein interactions, the presence of APP associated complexes. Our results demonstrated that both APP homomeric and C31/APP heteromeric complexes were correlated with cell death, indicating that C31 complexes with APP to recruit the interacting partners that initiate the signals related to cellular toxicity.

Park SA; Shaked GM; Bredesen DE; Koo EH

2009-10-01

359

Drosophila amyloid precursor protein-like is required for long-term memory.  

Science.gov (United States)

The amyloid precursor protein (APP) plays an important role in Alzheimer's disease (AD), a progressive neurodegenerative pathology that first manifests as a decline of memory. While the main hypothesis for AD pathology centers on the proteolytic processing of APP, very little is known about the physiological function of the APP protein in the adult brain. Likewise, whether APP loss of function contributes to AD remains unclear. Drosophila has been used extensively as a model organism to study neuronal function and pathology. In addition, many of the molecular mechanisms underlying memory are thought to be conserved from flies to mammals, prompting us to study the function of APPL, the fly APP ortholog, during associative memory. It was previously shown that APPL expression is highly enriched in the mushroom bodies (MBs), a specialized brain structure involved in olfactory memory. We analyzed memory in flies in which APPL expression has been silenced specifically and transiently in the adult MBs. Our results show that in adult flies, APPL is not required for learning but is specifically involved in long-term memory, a long lasting memory whose formation requires de novo protein synthesis and is thought to require synaptic structural plasticity. These data support the hypothesis that disruption of normal APP function may contribute to early AD cognitive impairment. PMID:21248128

Goguel, Valérie; Belair, Anne-Laure; Ayaz, Derya; Lampin-Saint-Amaux, Aurélie; Scaplehorn, Niki; Hassan, Bassem A; Preat, Thomas

2011-01-19

360

The Drosophila Homologue of the Amyloid Precursor Protein Is a Conserved Modulator of Wnt PCP Signaling  

Science.gov (United States)

Wnt Planar Cell Polarity (PCP) signaling is a universal regulator of polarity in epithelial cells, but it regulates axon outgrowth in neurons, suggesting the existence of axonal modulators of Wnt-PCP activity. The Amyloid precursor proteins (APPs) are intensely investigated because of their link to Alzheimer's disease (AD). APP's in vivo function in the brain and the mechanisms underlying it remain unclear and controversial. Drosophila possesses a single APP homologue called APP Like, or APPL. APPL is expressed in all neurons throughout development, but has no established function in neuronal development. We therefore investigated the role of Drosophila APPL during brain development. We find that APPL is involved in the development of the Mushroom Body ?? neurons and, in particular, is required cell-autonomously for the ?-axons and non-cell autonomously for the ?-axons growt