Expression and function of serum amyloid A, a major acute-phase protein, in normal and disease states

Proteomic analysis of the pathophysiological process involved in the antisnake venom effect of Mucuna pruriens extract

Previously, we reported the antisnake venom properties of a Mucuna pruriens seed extract (MPE) and tested its in vivo efficacy against Echis carinatus venom (EV) in short- (1 injection) and long-term (three weekly injections) treatments. The aim of the present study was to investigate plasma proteome changes associated with MPE treatments and identify proteins responsible for survival of envenomated mice (CHALLENGED mice). Six treatment groups were studied. Three control groups: one saline, one short-term and one long-term MPE treatment. One group received EV alone. Two test groups received EV with either a short-term or long-term MPE treatment (CHALLENGED mice). The plasma from each group was analysed by 2-DE/MALDI-TOF MS. The most significant changes with treatment were: albumin, haptoglobin, fibrinogen, serum amyloid A and serum amyloid P. Most of these changes were explained by EV effects on coagulation, inflammation and haemolysis. However, MPE treatments prevented the EV-induced elevation in HPT. Consequently, HPT levels were similar to controls in the plasma of CHALLENGED mice. The plasma of CHALLENGED mice showed substantial proteomic modifications. This suggests the mechanism of MPE protection involves the activation of counterbalancing processes to compensate for the imbalances caused by EV.

Is serum amyloid A an endogenous TLR4 agonist?

Serum amyloid A (SAA), a classical acute-phase protein, is produced predominantly by hepatocytes in response to injury, infection, and inflammation. It has been shown that SAA primes leukocytes and induces the expression and release of proinflammatory cytokines. Here, we report that SAA induces NO production by murine peritoneal macrophages. Using specific inhibitors, we showed that NO production was dependent on inducible NO synthase thorough the activation of ERK1/2 and p38 MAPKs. Moreover, SAA activity was decreased after proteolysis but not with polymyxin B, a lipid A antagonist. Finally, we found that NO production was dependent on functional TLR4, a receptor complex associated with innate immunity. Macrophages from C3H/HeJ and C57BL/10ScCr mice lacking a functional TLR4 did not respond to SAA stimulation. In conclusion, our study makes a novel observation that SAA might be an endogenous agonist for the TLR4 complex on macrophages. The contribution of this finding in amplifying innate immunity during the inflammatory process is discussed.

Serum amyloid A enhances plasminogen activation: implication for a role in colon cancer

We have recently reported that the acute phase protein serum amyloid A (SAA), is locally and differentially expressed in neoplastic tissues of human colon. In the present study, we demonstrate that SAA enhances the plasminogen activation (PA)-activity of HT-29 colon cancer cell line. Cell-associated PA-activity was measured following the plasminogen-dependent ability of the cells to cleave the chromogenic substrate S-2251. The SAA-enhanced PA-activity was inhibited by anti-SAA antibodies. These antibodies also decreased the basal PA-activity of HT-29 cells and neutralized their cytokines (Interleukin-1beta+Interleukin-6)-enhanced PA-activity. Using specific chromogenic substrates and the fibrin clot-lysis assay, we found that SAA enhances also the PA-activity mediated by purified urokinase- and tissue-type plasminogen activators. Together, the data indicate that SAA enhances plasminogen activation and suggest its possible role in plasmin(ogen)-mediated colon cancer progression.

An insight into the sialome of the soft tick, Ornithodorus parkeri

While hard ticks (Ixodidae) take several days to feed on their hosts, soft ticks (Argasidae) feed faster, usually taking less than 1h per meal. Saliva assists in the feeding process by providing a cocktail of anti-hemostatic, anti-inflammatory and immunomodullatory compounds. Saliva of hard ticks has been shown to contain several families of genes each having multiple members, while those of soft ticks are relatively unexplored. Analysis of the salivary transcriptome of the soft tick Ornithodorus parkeri, the vector of the relapsing fever agent Borrelia parkeri, indicates that gene duplication events have led to a large expansion of the lipocalin family, as well as of several genes containing Kunitz domains indicative of serine protease inhibitors, and several other gene families also found in hard ticks. Novel protein families with sequence homology to insulin growth factor-binding protein (prostacyclin-stimulating factor), adrenomedulin, serum amyloid A protein precursor and similar to HIV envelope protein were also characterized for the first time in the salivary gland of a blood-sucking arthropod. The sialotranscriptome of O. parkeri confirms that gene duplication events are an important driving force in the creation of salivary cocktails of blood-feeding arthropods, as was observed with hard ticks and mosquitoes. Most of the genes coding for expanded families are homologous to those found in hard ticks, indicating a strong common evolutionary path between the two families. As happens to all genera of blood-sucking arthropods, several new proteins were also found, indicating the process of adaptation to blood feeding still continues to recent times.

Analysis of SAA1 gene polymorphisms in the Greek population: rheumatoid arthritis and FMF patients relative to normal controls. Homogeneous distribution and low incidence of AA amyloidosis

OBJECTIVE

To address whether or not the rarity of amyloidosis in Greek patients with rheumatoid arthritis (RA) is related to specific alleles of single nucleotide polymorphisms (SNPs) in the 5'-flanking region and the exon 3 of the SSA1 gene.

METHODS

The genotypes of the -13T/C SNP in the 5'-flanking region of the SAA1 gene and the two SNPs within exon 3 of SAA1 (2995C/T and 3010C/T polymorphisms) were determined in 88 Greek patients with RA, 14 patients with familial Mediterranean fever (FMF) and 110 healthy controls. Linkage disequilibrium and haplotype frequencies involving -13T/C, 2995C/T and 3010C/T in these populations were tested and estimated, respectively.

RESULTS

The genotypic distribution and allelic frequencies were similar in all groups tested. SNPs 2995 and 3010 were in linkage disequilibrium for all study populations (p < 0.05), whereas SNP -13 was not in linkage disequilibrium with either 2995 or 3010 (p > or = 0.05). Two major haplotypes presented in all patients with RA and FMF and controls: -13C; 2995T; 3010C (-13C; alpha) and -13C; 2995C; 3010T (-13C; beta). The -13T allele was linked with the gamma haplotype in Greek patients with RA and controls. The frequency of the -13T allele was found to be very rare in all groups tested.

CONCLUSIONS

In conclusion, the rarity of the putative amyloidogenic -13T allele in Greek populations may be related to low prevalence of AA amyloidosis development in Greek RA patients.

Serum amyloid a is a biomarker of acute exacerbations of chronic obstructive pulmonary disease

RATIONALE

Much of the total disease burden and cost of chronic obstructive pulmonary disease (COPD) is associated with acute exacerbations of COPD (AECOPD). Serum amyloid A (SAA) is a novel candidate exacerbation biomarker identified by proteomic screening.

OBJECTIVES

To assess SAA as a biomarker of AECOPD.

METHODS

Biomarkers were assessed (1) cross-sectionally (stable vs. AECOPD; 62 individuals) and (2) longitudinally with repeated measures (baseline vs. AECOPD vs. convalescence; 78 episodes in 37 individuals). Event severity was graded (I, ambulatory; II, hospitalized; III, respiratory failure) based on consensus guidelines.

MEASUREMENTS AND MAIN RESULTS

Presumptively newly acquired pathogens were associated with onset of symptomatic AECOPD. In the cross-sectional study, both SAA and C-reactive protein (CRP) were elevated at AECOPD onset compared with stable disease (SAA median, 7.7 vs. 57.6 mg/L; P < 0.01; CRP median, 4.6 vs. 12.5 mg/L; P < 0.01). Receiver operator characteristics analysis was used to generate area-under-curve values for event severity. SAA discriminated level II/III events (SAA, 0.88; 95% confidence interval, 0.80-0.94 vs. CRP, 0.80; 95% confidence interval, 0.70-0.87; P = 0.05). Combining SAA or CRP with major symptoms (Anthonisen criteria, dyspnea) did not further improve the prediction model for severe episodes. IL-6 and procalcitonin were not informative.

CONCLUSIONS

SAA is a novel blood biomarker of AECOPD that is more sensitive than CRP alone or in combination with dyspnea. SAA may offer new insights into the pathogenesis of AECOPD.

Protein and mRNA characterization in human colorectal carcinoma cell lines with different metastatic potentials

Metastasis, the important characteristic of malignant tumors, is closely associated with a series of changes in the expressions of genes and proteins. In this study, we compared mRNA and protein expressions in a pair of human colorectal carcinoma cell lines named SW620 and SW480 with different metastatic potentials by suppression subtractive hybridization and 2-dimensional gel electrophoresis combined with the matrix-assisted laser desorption/ionization time-of-flight mass spectrometer. After suppression subtractive hybridization and differential screening, 24 differentially expressed gene fragments were obtained, including 9 known genes and 15 novel genes. Nine known genes, such as Cytochrome C, Oxidase II and III, Serum amyloid A, Mitotic Control Protein dis3, Eukaryotic Translation Initiation Factor 4A, function in the process of growth and differentiation, transcription, apoptosis, signal transduction. Six novel genes were found to locate in chromosome 5. Northern blot further confirmed the results. For protein analysis, 16 significantly different protein spots were detected using 2-dimensional gel electrophoresis and peptide mass fingerprinting analysis. The results were confirmed by Western blot. The peptide mass fingerprintings of spots were then compared with the NCBI and SWISS PROT database. The differentially expressed proteins included Galectin-1, Annexin A1, Casein kinase 2, Cytochrome c oxidase subunit VIb, S-100D calcium-binding protein, which may be involved in cell differentiation and proliferation, signal transduction, cell adhesion and migration, and tumor evasion of immune responses. An analysis of these genes and proteins reiterated much of our understanding of the metastatic process and also offered some identified targets without previously characterized functions, especially the novel metastasis associated genes, to be further investigated. Moreover, the results of the phenotypic function-related expression mapping analysis at the mRNA and protein level revealed obvious complementarities, providing important clues for further study of the molecular mechanism of metastasis, metastasis control and possible targets for cancer gene therapy.

Serum amyloid A mediates human neutrophil production of reactive oxygen species through a receptor independent of formyl peptide receptor like-1

Serum amyloid A (SAA) is one of the acute-phase reactants, a group of plasma proteins that increases immensely in concentration during microbial infections and inflammatory conditions, and a close relationship between SAA levels and disease activity in rheumatoid arthritis (RA) has been observed. RA is an inflammatory disease, where neutrophils play important roles, and SAA is thought to participate in the inflammatory reaction by being a neutrophil chemoattractant and inducer of proinflammatory cytokines. The biological effects of SAA are reportedly mediated mainly through formyl peptide receptor like-1 (FPRL1), a G protein-coupled receptor (GPCR) belonging to the formyl peptide receptor family. Here, we confirmed the affinity of SAA for FPRL1 by showing that stably transfected HL-60 cells expressing FPRL1 were activated by SAA and that the response was inhibited by the use of the FPRL1-specific antagonist WRWWWW (WRW4). We also show that SAA activates the neutrophil NADPH-oxidase and that a reserve pool of receptors is present in storage organelles mobilized by priming agents such as TNF-alpha and LPS from Gram-negative bacteria. The induced activity was inhibited by pertussis toxin, indicating the involvement of a GPCR. However, based on FPRL1-specific desensitization and use of FPRL1 antagonist WRW4, we found the SAA-mediated effects in neutrophils to be independent of FPRL1. Based on these findings, we conclude that SAA signaling in neutrophils is mediated through a GPCR, distinct from FPRL1. Future identification and characterization of the SAA receptor could lead to development of novel, therapeutic targets for treatment of RA.

Protein expression profiling reveals distinctive changes in serum proteins associated with chronic pancreatitis

OBJECTIVE

Testing of serum for protein patterns to monitor progression of suspected to definite chronic pancreatitis (CP).

METHODS

Serum samples of CP patients and healthy volunteers were fractionated on anion exchange columns and analyzed by surface-enhanced laser desorption/ionization-time-of-flight mass spectrometry to elucidate CP-related protein alterations and to identify biomarkers for this disease. Potential biomarkers were purified and identified by mass spectrometry.

RESULTS

In total, 258 protein peaks were found that discriminated between the 2 groups. Analysis revealed 28 most prominent peaks on immobilized metal affinity capture coupled with Cu and CM10 protein chips, covering the m/z range between 3.3 and 33.3 kd. Performing multivariate pattern analysis, the best pattern model was obtained using fraction 6 on immobilized metal affinity capture coupled with Cu arrays with a sensitivity of 96% and a specificity of 84%. Using a combination of matrix-assisted laser desorption-ionization-time-of-flight mass spectrometry and immunodepletion, we identified 14-m/z peaks. The proteins were found to be significantly decreased in CP serum and were identified as retinol-binding protein, serum amyloid-alpha, apolipoprotein A-II (Apo A-II), Apo C-I, Apo C-II, Apo C-III, and transthyretin and truncated forms thereof.

CONCLUSIONS

Distinct protein profile differences exist between normal and CP serum and reflect the metabolic and inflammatory condition in CP patients. The identified protein panel may eventually serve as a diagnostic marker set for CP.

Proteomic analysis of ovomucoid hypersensitivity in mice by two-dimensional difference gel electrophoresis (2D-DIGE)

There is a need to develop reliable methods to assess the safety of genetically modified and other novel foods. The aim of this study was to identify protein biomarkers of food allergy in mice exposed to ovomucoid (OVM), a major food allergen found in chicken egg white. BALB/c mice were repeatedly sensitized by gavage with OVM and cholera toxin (CT) and control mice were exposed to a mixture of amino acids with CT. At the endpoint, all mice were challenged intraperitoneally with OVM and alum. Type-1 hypersensitivity was confirmed in OVM-sensitized mice by observation of clinical signs of anaphylaxis and elevated levels of plasma histamine, OVM-specific IgE and OVM-specific IgG by ELISA. Differential protein expression was assessed in albumin-depleted plasma as well as in mesenteric lymph node, liver, spleen, and ileum by two-dimensional difference gel electrophoresis (2D-DIGE). Differentially expressed proteins were identified by liquid chromatography with tandem mass spectrometry. Plasma proteins overexpressed in OVM-sensitized mice included haptoglobin (41-fold), serum amyloid A (19-fold) and peroxiredoxin-2 (1.9-fold). Further validation of these plasma proteins in other animal models of food allergy with different food allergens is required to assess their potential as candidate biomarkers for use in evaluating the allergenicity of novel foods.

Ankylosing spondylitis-related secondary amyloidosis responded well to etanercept: a report of three patients

Secondary (AA) amyloidosis is one of the most significant complications of ankylosing spondylitis (AS) that frequently leads to proteinuria and renal dysfunction. Anti-tumor necrosis factor alpha (anti-TNF) agents are promising in inducing clinical remission by suppressing systemic inflammation in AA amyloidosis. We report three cases with AS-related AA amyloidosis that responded well to etanercept therapy. Despite treatment with disease modifying anti-rheumatic drugs, all three patients had active AS, marked proteinuria, impaired renal function, and low serum albumin level. During 1-year treatment with etanercept, all patients experienced gradual improvement in all of these parameters.

Quotidian hemodialysis and inflammation associated with chronic kidney disease

The mortality rate of chronic dialysis patients in the United States is 24% per year per the 2006 United States Renal Data System. Although there have been marked improvements in dialysis technology, cardiovascular disease is the principal cause of mortality in end-stage renal disease patients. Inflammation and left ventricular hypertrophy both contribute to atherosclerosis. Hemodialysis 3 times a week is the most commonly used form of dialysis in the United States. The multicenter hemodialysis (HEMO) study hypothesized that an increase in dialysis dose and use of high-flux membranes would improve mortality and decrease morbidity. This study failed to show decreases in mortality. In other studies, however, there appears to be improved morbidity with more frequent dialysis including daily nocturnal hemodialysis and short-daily hemodialysis. The more frequent dialysis may have some beneficial effect on the inflammatory process that occurs in end-stage renal disease.

Aspirin-Triggered Lipoxins Override the Apoptosis-Delaying Action of Serum Amyloid A in Human Neutrophils: A Novel Mechanism for Resolution of Inflammation

Elevated plasma levels of the acute-phase reactant serum amyloid A (SAA) have been used as a marker and predictor of inflammatory diseases. SAA regulates leukocyte activation; however, it is not known whether it also modulates neutrophil apoptosis, which is critical to the optimal expression and resolution of inflammation. Culture of human neutrophils with SAA (0.1-20 microg/ml) markedly prolonged neutrophil longevity by delaying constitutive apoptosis. SAA evoked concurrent activation of the ERK and PI3K/Akt signaling pathways, leading to phosphorylation of BAD at Ser(112) and Ser(136), respectively, and to prevention of collapse of mitochondrial transmembrane potential, cytochrome c release, and caspase-3 activation. These actions were abrogated by pharmacological inhibition of the formyl peptide receptor, ERK or PI3K. Furthermore, aspirin-triggered 15-epi-lipoxin A(4) (15-epi-LXA(4)) and its stable analog 15-epi-16-p-fluorophenoxy-LXA(4), which binds to the same receptor as SAA, effectively overrode the antiapoptosis signal from SAA even when neutrophils were treated with 15-epi-LXA(4) at either 1 or 4 h postculture with SAA. 15-Epi-LXA(4) itself did not affect neutrophil survival and apoptosis. Our results indicate that SAA at clinically relevant concentrations promotes neutrophil survival by suppressing the apoptotic machinery, an effect that can be opposed by 15-epi-LXA(4). The opposing actions of SAA and aspirin-triggered 15-epi-LXA(4) may contribute to the local regulation of exacerbation and resolution of inflammation, respectively.

Natural history and outcome in systemic AA amyloidosis

BACKGROUND

Deposition of amyloid fibrils derived from circulating acute-phase reactant serum amyloid A protein (SAA) causes systemic AA amyloidosis, a serious complication of many chronic inflammatory disorders. Little is known about the natural history of AA amyloidosis or its response to treatment.

METHODS

We evaluated clinical features, organ function, and survival among 374 patients with AA amyloidosis who were followed for a median of 86 months. The SAA concentration was measured serially, and the amyloid burden was estimated with the use of whole-body serum amyloid P component scintigraphy. Therapy for inflammatory diseases was administered to suppress the production of SAA.

RESULTS

Median survival after diagnosis was 133 months; renal dysfunction was the predominant disease manifestation. Mortality, amyloid burden, and renal prognosis all significantly correlated with the SAA concentration during follow-up. The risk of death was 17.7 times as high among patients with SAA concentrations in the highest eighth, or octile, (>or=155 mg per liter) as among those with concentrations in the lowest octile (<4 mg per liter); and the risk of death was four times as high in the next-to-lowest octile (4 to 9 mg per liter). The median SAA concentration during follow-up was 6 mg per liter in patients in whom renal function improved and 28 mg per liter in those in whom it deteriorated (P<0.001). Amyloid deposits regressed in 60% of patients who had a median SAA concentration of less than 10 mg per liter, and survival among these patients was superior to survival among those in whom amyloid deposits did not regress (P=0.04).

CONCLUSIONS

The effects of renal dysfunction dominate the course of AA amyloidosis, which is associated with a relatively favorable outcome in patients with SAA concentrations that remain in the low-normal range (<4 mg per liter).

Effect of zinc, copper, and calcium on the structure and stability of serum amyloid A

Serum amyloid A (SAA) is a highly conserved acute phase reactant protein, and its concentration in serum can increase up to approximately 1000 times after an inflammatory stimuli. SAA is mainly associated with high-density lipoproteins in serum, and its main function appears to involve cholesterol transport and lipid metabolism. However, SAA has also been associated with many other functions and a number of diseases, although these potential links remain poorly understood. The three-dimensional structure of SAA is not known, but we have shown that murine SAA2.2 can exist in solution as a marginally stable hexamer, which at 37 degrees C dissociates to a monomeric species that misfolds irreversibly and self-assembles into amyloid fibrils. Thus, the structure and function of SAA in vivo appear to be modulated when it binds to other proteins or small ligands. Herein, the effect of copper (Cu2+), zinc (Zn2+), and calcium (Ca2+) on the structure and stability of SAA2.2 in aqueous solution was examined using various probes of quaternary, tertiary, and secondary structure. At different concentrations of metals, including those found in the serum, the results show that the structure and stability of SAA2.2 are differently affected depending on the metal type and concentration. Copper (10-100 microM) was found to shift the equilibrium from hexamer to monomer without affecting significantly the stability of the tertiary and secondary structure of SAA2.2. In contrast, zinc (1-10 microM) bound to SAA2.2 and stabilized its quaternary, tertiary, and secondary structure. Calcium (1-10 mM) destabilized all elements of SAA2.2 structure and induced its aggregation at 10 mM. Complete aggregation of SAA2.2 was also observed when it was incubated with 1 mM Cu2+ or Zn2+, further demonstrating the tenuous structure and stability of SAA2.2. Thus, these results suggest that the many functional and pathological roles attributed to SAA may rely on its precarious structure, modulated by its interaction with ligands under homeostasis conditions and during the acute phase response.

Molecular interactions of acute phase serum amyloid A: possible involvement in carcinogenesis

Acute phase serum amyloid A (A-SAA) is a well-known marker of inflammation. The present review summarizes data on the regulation of A-SAA expression, signaling pathways which it is involved in, its effects, and possible influences on progression of malignant tumors.

Interaction between serum amyloid A and leukocytes—A possible role in the progression of vascular complications in diabetes

Diabetes mellitus is associated with an increased incidence of cardiovascular events and microvascular complications. Serum amyloid A (SAA), a HDL apolipoprotein is a risk marker for cardiovascular disease. A permanent increase in SAA plasma levels is observed in diabetics. Because SAA acts on leukocytes, we evaluated whether the synthesis of proinflammatory cytokines and migration of neutrophils and monocytes induced by SAA is affected in diabetics. Cells, isolated from human blood, were cultured in the presence of SAA. TNF-alpha, IL-1beta, IL-8 and IL-1ra levels were measured by ELISA in the culture supernatants and in serum of subjects. Neutrophils and monocytes migration were followed in a chemotaxis chamber. We make the novel observation that neutrophils and monocytes of diabetics are more responsive to SAA for the induction of the proinflammatory cytokine IL-1beta and the proangiogenic and chemotactic protein IL-8. Incremental TNF-alpha production was also found to occur when monocytes were stimulated with SAA. Cell migration was also increased. The increased production of cytokines and increased migration of leukocytes from diabetics in response to SAA may contribute to a sustained accumulation and activation of inflammatory cells in the disease. Accordingly, the hyper-responsiveness of leukocytes to SAA may be relevant to the proinflammatory conditions associated to vascular complications in diabetic patients.

Serum Amyloid A Induces Monocyte Tissue Factor

C-reactive protein (CRP) and serum amyloid A (SAA) increase in the blood of patients with inflammatory conditions and CRP-induced monocyte tissue factor (TF) may contribute to inflammation-associated thrombosis. This study demonstrates that SAA is a potent and rapid inducer of human monocyte TF. SAA induced TF mRNA in PBMC within 30 min and optimal procoagulant activity within 4 h, whereas CRP (25 mug/ml)-induced activity was minimal at this time. Unlike CRP, SAA did not synergize with LPS. Procoagulant activity was inhibited by anti-TF and was dependent on factors VII and X, and TF Ag levels were elevated on CD14(+) monocytes. Responses were optimal with lymphocytes, although these were not obligatory. Inhibitor studies indicate activation of NF-kappaB through the ERK1/2 and p38 MAPK pathways; the cyclo-oxygenase pathway was not involved. SAA-induced TF was partially inhibited by high-density lipoprotein, but not by low-density lipoprotein or by apolipoprotein A-I. SAA is a ligand for the receptor for advanced glycation end products (RAGE), and TF generation was suppressed by approximately 50% by a RAGE competitor, soluble RAGE, and by approximately 85% by anti-RAGE IgG. However, another RAGE ligand, high mobility group box-1 protein, capable of inducing monocyte chemotactic protein-1 mRNA in 2 h, did not induce TF within 24 h. Cross-linking studies confirmed SAA binding to soluble RAGE. Elevated SAA is a marker of disease activity in patients with rheumatoid arthritis, and PBMC from patients with rheumatoid arthritis were more sensitive to SAA than normals, suggesting a new link between inflammation and thrombosis.

The acute-phase proteins serum amyloid A and C reactive protein in transudates and exudates

The distinction between exudates and transudates is very important in the patient management. Here we evaluate whether the acute-phase protein serum amyloid A (SAA), in comparison with C reactive protein (CRP) and total protein (TP), can be useful in this discrimination. CRP, SAA, and TP were determined in 36 exudate samples (27 pleural and 9 ascitic) and in 12 transudates (9 pleural and 3 ascitic). CRP, SAA, and TP were measured. SAA present in the exudate corresponded to 10% of the amount found in serum, that is, the exudate/serum ratio (E/S) was 0.10 ± 0.13. For comparison, the exudate/serum ratio for CRP and TP was 0.39 ± 0.37 and 0.68 ± 0.15, respectively. There was a strong positive correlation between serum and exudate SAA concentration (r = 0.764;p < 0.0001). The concentration of SAA in transudates was low and did not overlap with that found in exudates (0.02-0.21 versus 0.8–360.5 g/mL). SAA in pleural and ascitic exudates results mainly from leakage of the serum protein via the inflamed membrane. A comparison of the E/S ratio of SAA and CRP points SAA as a very good marker in discriminating between exudates and transudates.

Serum amyloid A in autoimmune thrombosis

The objectives of this study were (1) to determine how levels of serum amyloid A (SAA), high sensitivity C-reactive protein (CRP) and interleukin-6 (IL-6) correlate to autoimmune diseases in patients with or without thrombosis, and (2) to discuss the parameters that influence the relative SAA values. SAA, CRP and IL-6 concentrations were determined by enzyme linked immunosorbent assay (ELISA). 84 patients with secondary antiphospholipid syndrome (SAPS), primary antiphospholipid syndrome (PAPS), systemic lupus erythematosus with antiphospholipid antibodies (SLE+aPL), SLE, venous thrombosis (VT), arterial thrombosis (AT) were compared to healthy donors (n=60). The percentages of patients above cut-off were highest in the SAPS, SLE and SLE+aPL groups. Significant differences were observed between healthy donors and inflammatory groups of patients (SAPS and SLE+aPL) in all three measured parameters. SAA and CRP were shown to be correlated to a greater extent in SAPS patients than SLE+aPL patients. In summary, this cross-sectional, retrospective, small study and accompanying clinical considerations limit the ability to make definite conclusions. SAA would not serve as a useful marker for venous, arterial thrombosis or PAPS (pro-coagulant events). It could however, be a good predictor of progression from a non-inflammatory thrombotic condition to an inflammatory one.

Serum amyloid A is an endogenous ligand that differentially induces IL-12 and IL-23

The acute-phase proteins, C-reactive protein and serum amyloid A (SAA), are biomarkers of infection and inflammation. However, their precise role in immunity and inflammation remains undefined. We report in this study a novel property of SAA in the differential induction of Th1-type immunomodulatory cytokines IL-12 and IL-23. In peripheral blood monocytes and the THP-1 monocytic cell line, SAA induces the expression of IL-12p40, a subunit shared by IL-12 and IL-23. SAA-stimulated expression of IL-12p40 was rapid (< or = 4 h), sustainable (> or = 20 h), potent (up to 3380 pg/ml/10(6) cells in 24 h), and insensitive to polymyxin B treatment. The SAA-stimulated IL-12p40 secretion required de novo protein synthesis and was accompanied by activation of the transcription factors NF-kappaB and C/EBP. Expression of IL-12p40 required activation of the p38 MAPK and PI3K. Interestingly, the SAA-induced IL-12p40 production was accompanied by a sustained expression of IL-23p19, but not IL-12p35, resulting in preferential secretion of IL-23, but not IL-12. These results identify SAA as an endogenous ligand that potentially activates the IL-23/IL-17 pathway and present a novel mechanism for regulation of inflammation and immunity by an acute-phase protein.

Inflammation-responsive transcription factor SAF-1 activity is linked to the development of amyloid A amyloidosis

Abundantly expressed serum amyloid A (SAA) protein under chronic inflammatory conditions gives rise to insoluble aggregates of SAA derivatives in multiple organs resulting in reactive amyloid A (AA) amyloidosis, a consequence of rheumatoid arthritis, Crohn's disease, ankylosing spondylitis, familial Mediterranean fever, and Castleman's disease. An inflammation-responsive transcription factor, SAF (for SAA activating factor), has been implicated in the sustained expression of amyloidogenic SAA under chronic inflammatory conditions. However, its role in the pathogenesis of AA amyloidosis has thus far remained obscure. In this paper we have shown that SAF-1, a major member of the SAF family, is abundantly present in human AA amyloidosis patients. To assess whether SAF-1 is directly linked to the pathogenesis of AA amyloidosis, we have developed a SAF-1 transgenic mouse model. SAF-1-overexpressing mice spontaneously developed AA amyloidosis at the age of 14 mo or older. Immunohistochemical analysis confirmed the nature of the amyloid deposits as an AA type derived from amyloidogenic SAA1. Furthermore, SAF-1 transgenic mice rapidly developed severe AA amyloidosis in response to azocasein injection, indicating increased susceptibility to inflammation. Also, during inflammation SAF-1 transgenic mice exhibited a prolonged acute phase response, leading to an extended period of SAA synthesis. Together, these results provide direct evidence that SAF-1 plays a key role in the development of AA amyloidosis, a consequence of chronic inflammation.

Acute Phase Proteins in Bovine Milk in an Experimental Model of Staphylococcus aureus Subclinical Mastitis

The objectives were to establish the origin of 2 acute phase proteins in milk during subclinical bovine mastitis and to characterize the relationship between those proteins in milk and blood. Haptoglobin (Hp) and mammary-associated serum amyloid A (M-SAA3) appear in milk during mastitis, whereas Hp and serum amyloid A increase in serum during mastitis. The concentrations of these proteins were determined in an experimental model using a field strain of Staphylococcus aureus to induce subclinical mastitis in dairy cows. The expression of mRNA coding for these proteins was assessed and the presence of M-SAA3 in mammary tissues was determined using immunocytochemistry. Increases of M-SAA3 and Hp in milk occurred within 12 h of Staphylococcus aureus infusion, with peak concentrations occurring 3 d after infusion of the bacteria. The increase of acute phase proteins in milk (15 h) preceded the increase in serum concentrations of both proteins (24 h). Expression of mRNA for M-SAA3 and Hp increased in both mammary and hepatic tissues 48 h after infusion of the mammary glands. In mammary tissue, the increase of M-SAA3 mRNA was greater than the increase in Hp mRNA expression, whereas in hepatic tissue, the increase in M-SAA3 mRNA was less than that for Hp mRNA. Immunocytochemistry demonstrated that M-SAA3 protein was present within secretory epithelial cells at significantly higher levels in infected mammary glands than in control tissues. These proteins, which have host defense and antibacterial activities, may play a significant role in the early response to invasion of mammary tissues by pathogenic bacteria.

Temporal changes in concentrations of serum amyloid-A and haptoglobin and their associations with weight gain in neonatal reindeer calves

Age-related changes in serum concentrations of two acute phase proteins (APPs), haptoglobin (Hp) and serum amyloid-A (SAA) were investigated in newborn reindeer calves. Repeated blood samples were obtained from 51 reindeer calves at ages 0-32 days (2-4 samples from each calf). An increase of SAA concentrations was observed during the first 2 weeks of life. However, by the end of the observation period, SAA concentrations had decreased to levels below those of the first week. Serum Hp concentrations increased throughout the observation period. SAA concentrations in the second week had a negative association with weight gain during the entire study period (4 months). These time-related changes in APP concentrations suggest that these proteins have a role in the defence and adaptation mechanisms of newborn reindeer calves. Possible reasons for these changes include the presence of APP mediators in the colostrum, exposure to environmental pathogens after birth and age-related changes in hepatic synthesis of APP.

Serum amyloid A: a marker of adiposity-induced low-grade inflammation but not of metabolic status

OBJECTIVE

Adipocytes secrete a series of acute phase proteins including serum amyloid A (SAA); the link with metabolic status is unknown. We studied the variations of expression of the SAA gene in adipose and liver tissues and of SAA serum levels, as well as their relationships with metabolic features during weight loss.

RESEARCH METHODS AND PROCEDURES

Plasmatic variations of SAA, inflammatory markers (high sensitivity C-reactive protein, interleukin-6, fibrinogen, and orosomucoid), and adipokines (adiponectin, leptin) were studied in 60 morbidly obese patients before and after gastric surgery. For 10 subjects, SAA mRNA expression was measured at baseline in subcutaneous white adipose tissue (scWAT) and visceral white adipose tissue (vWAT) and in the liver. The evolution of SAA mRNA expression was also studied after surgery in scWAT.

RESULTS

SAA serum concentration displayed a significant reduction 3 months after surgery and remained stable beyond 6 months. mRNA expression of inducible SAA isoforms (SAA 1 and 2) in scWAT was higher than in vWAT (p = 0.01) and the liver (p < 0.01) and correlated significantly with BMI, SAA, and high sensitivity C-reactive protein serum concentrations but not with metabolic markers (glucose, insulin, lipid parameters, adiponectin). SAA serum level and its variation during weight loss significantly correlated with adiposity markers (BMI and adipocyte volume, p < 0.01) and inflammatory markers but not with variations of metabolic parameters. The variations of SAA expression in scWAT after surgery correlated with changes in BMI and SAA protein serum levels (p < 0.05).

DISCUSSION

SAA can be considered as a marker of adiposity-induced low-grade inflammation but not of the metabolic status of obese subjects.

Temporal gene induction patterns in sheepshead minnows exposed to 17β-estradiol

Gene arrays provide a powerful method to examine changes in gene expression in fish due to chemical exposures in the environment. In this study, we expanded an existing gene array for sheepshead minnows (Cyprinodon variegatus) (SHM) and used it to examine temporal changes in gene expression for male SHM exposed to 100 ng 17beta-estradiol (E(2))/L for five time points between 0 and 48 hr. We found that in addition to the induction of genes involved in oocyte development (vitellogenin [VTG], zona radiata [ZRP]), other genes involved in metabolism and the inflammatory response are also affected. We identified five patterns of temporal induction in genes whose expression was modified due to E(2) exposure. We validated the gene array data for the expression of VTG 1, VTG 2, ZRP 2 and ZRP 3 and found that with low levels of exogenous E(2) (100 ng E(2)/L) exposure, ZRP expression precedes VTG expression. However, at higher concentrations of E(2) (500 ng E(2)/L), the difference in temporal expression appears to be lost. Exposure to high levels of environmental contaminants may affect the normal ordered expression of genes required for reproduction. Gene expression profiling using arrays promises to be a valuable tool in the field of environmental toxicology. As more genes are identified for species used in toxicological testing, researchers will be better able to predict adverse effects to chemical exposures and to understand the relationships between changes in gene expression and changes in phenotype.

Maternal and cord blood levels of serum amyloid A, C-reactive protein, tumor necrosis factor-alpha, interleukin-1beta, and interleukin-8 during and after delivery

C-reactive protein (CRP) and serum amyloid A (SAA) are acute-phase proteins mainly synthesized by the liver in response to some cytokines. They are potentially useful to diagnosing infection and monitoring different clinical conditions. The aim of this study was to measure SAA and CRP in maternal and cord blood during and after delivery and try to correlate these proteins with tumor necrosis factor-α , interleukin-1β, and interleukin-8. Acute-phase proteins and cytokines were measured by ELISA in 24 healthy pregnant women undergoing vaginal delivery or Cesarean section. Cord blood samples in addition to maternal blood were collected. SAA and CRP reached the maximum maternal serum levels 24 hours after delivery, while cytokines remained constant over time. SAA and CRP were significantly higher in maternal serum than in newborn's (P < .001) at the moment of delivery. SAA and CRP, regardless of the type of delivery, reproduce the common pattern observed in most inflammatory conditions. Proinflammatory cytokine serum levels do not mirror the increase in SAA and CRP levels.

Purification and separation of hydrophobic serum amyloid A precursor isoforms by a one-step preparative method

The levels of two major serum amyloid A precursor isoforms, SAA1 and SAA2, which are associated with high-density lipoproteins (HDL) are increased during inflammation. The hydrophobic character and the small size difference--corresponding to just 0.8 kDa--between these two members of the SAA family hinder their separation and purification on a large scale by conventional methods. In the current work, both mouse SAA proteins were purified from HDL-SAA and acute-phase serum within 10 h in a one-step procedure using the high-resolution, continuous-elution preparative gel electrophoresis Prep-Cell system in combination with Tris/Glycine SDS-PAGE. Moreover, applying the Tris/Tricine system on the Prep-Cell resulted not only in purification of the SAA proteins, but also in their separation within 16 h. The SAA isoforms were freed from SDS using a Centricon concentrator and were identified using monoclonal antibodies. Optical density profile plots of gel protein or Western blot bands in combination with a colorimetric spectrophotometric protein assay showed that the recovery of the isoforms ranged from 38% to 60%. These results show that the preparative gel electrophoresis system Prep-Cell is a suitable device for separating SAA1 and SAA2 proteins in a simplified, convenient, and fast procedure, which can be applied on a small or large scale.

Serum Amyloid A Promotes Cholesterol Efflux Mediated by Scavenger Receptor B-I

Serum amyloid A (SAA) is an acute phase protein whose expression is markedly up-regulated during inflammation and infection. The physiological function of SAA is unclear. In this study, we reported that SAA promotes cellular cholesterol efflux mediated by scavenger receptor B-I (SR-BI). In Chinese hamster ovary cells, SAA promoted cellular cholesterol efflux in an SR-BI-dependent manner, whereas apoA-I did not. Similarly, SAA, but not apoA-I, promoted cholesterol efflux from HepG2 cells in an SR-BI-dependent manner as shown by using the SR-BI inhibitor BLT-1. When SAA was overexpressed in HepG2 cells using adenovirus-mediated gene transfer, the endogenously expressed SAA promoted SR-BI-dependent efflux. To assess the effect of SAA on SR-BI-mediated efflux to high density lipoprotein (HDL), we compared normal HDL, acute phase HDL (AP-HDL, prepared from mice injected with lipopolysaccharide), and AdSAA-HDL (HDL prepared from mice overexpressing SAA). Both AP-HDL and AdSAA-HDL promoted 2-fold greater cholesterol efflux than normal HDL. Lipid-free SAA was shown to also stimulate ABCA1-dependent cholesterol efflux in fibroblasts, in line with an earlier report (Stonik, J. A., Remaley, A. T., Demosky, S. J., Neufeld, E. B., Bocharov, A., and Brewer, H. B. (2004) Biochem. Biophys. Res. Commun. 321, 936-941). When added to cells together, SAA and HDL exerted a synergistic effect in promoting ABCA1-dependent efflux, suggesting that SAA may remodel HDL in a manner that releases apoA-I or other efficient ABCA1 ligands from HDL. SAA also facilitated efflux by a process that was independent of SR-BI and ABCA1. We conclude that the acute phase protein SAA plays an important role in HDL cholesterol metabolism by promoting cellular cholesterol efflux through a number of different efflux pathways.

Incidence and risk factors of venous thromboembolism (VTD) in patients with amyloidosis

Background

Coagulation problems in amyloidosis are historically associated with bleeding tendencies (mostly Factor X abnormalities). Increased clotting was observed in isolated cases diagnosed with low-grade disseminated intravascular coagulation (DIC). Problem of venous thromboembolic disaease (VTD) in amyloidosis was not systematically investigated.

Methods

We evaluated frequency of VTD and risk factors for VTD in 56 consecutive amyloidosis patients with a documented disease evaluated and followed up at our Center from 1991–2001. Data was collected in 5 categories: (a) demographics, (b) disease and treatment, (c) thrombosis case information, (d) major risk factors for thrombosis and (e) baseline laboratory data. Univariable correlates of VTD were assessed using Kaplan-Meier analysis and Cox proportional hazards analysis.

Results

Mean age of the patients was 67 (years range 21 – 83). Male/female percentage ratio was 70/30. 29 % of the patients had high creatinine level (> 1.4 mg/dl). Personal or family history of VTD was recorded in 2 and 0 % of patients, respectively. Known hypercoagulable state was present in 1 patient (2%). 8 % of patients were smokers. Of 56 patients, 6 developed VTD (11%). Median time from diagnosis of amyloidosis to VTD was 12.5 month (range 1–107). Treatment was given within a median of 1 month (range 0–4) from the development of thrombosis. Only sites of VTD were lower extremities. No cases were associated with I.V. line. 1 case (17 %) was identified postoperatively. We identified several univariable correlates of VTD in amyloid patients, including greater age at diagnosis (HR-2.99, P = .041), personal history of DVT (HR-47.7, P = .006) and immobility (HR-11.78, P = .006). Presence of circulating serum M-protein had protective role in our analysis (HR-.08, P = .031). There was no correlation with the type of treatment patients were receiving.

Conclusion

Risk for thromboembolic diseases in patients with amyloidosis is similar to one previously described for multiple myeloma. Additional studies with higher number of thromboembolic events could help to further elucidate risk factors for VTD in this population of patients.

From hexamer to amyloid: marginal stability of apolipoprotein SAA2.2 leads to in vitro fibril formation at physiological temperature

Serum amyloid A (SAA) is a major acute phase reactant and a small apolipoprotein of high density lipoproteins (HDL) in the serum. In cases of prolonged inflammation, SAA may form amyloid fibrils, leading to the disease of amyloid A (AA) amyloidosis. Recently, we have shown that murine SAA2.2, a non-amyloidogenic isoform in vivo, forms a hexamer in vitro containing a putative central channel. It is reported herein that upon thermal denaturation, hexameric SAA2.2 irreversibly dissociates to a misfolded monomer at physiological temperature, formation of which coincides with a significant loss of alpha-helical and gain of beta-sheet structure. When SAA2.2 is incubated for several days at 37 degrees C, sedimentation analytical ultracentrifugation reveals the presence of soluble high molecular weight aggregates, which upon further incubation undergo subsequent self-assembly into amyloid fibrils. Limited proteolysis experiments suggest that the in vitro amyloidogenecity of SAA2.2 is related to structural alteration in its N-terminus. Our observation that SAA2.2 can form amyloid fibrils in vitro at physiological temperatures suggests that SAA2.2's inability to cause amyloidosis may be related to other factors, such as the stabilization of hexameric SAA2.2 (possibly through ligand binding), and/or the slow kinetics of aberrant misfolding and self-assembly.

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

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

Cryodetector mass spectrometry profiling of plasma samples for HELLP diagnosis: An exploratory study

The cryodetector MS-based screening method enables the rapid and reliable separation of hemolysis, elevated liver enzymes, and low platelets syndrome (HELLP) patients from healthy women. For developing the assay, plasma protein abundances from patients suffering from HELLP were profiled before and after delivery and compared to healthy pregnant and nonpregnant control individuals, using a TOF mass spectrometer equipped with a cryodetector system. The spectra were well reproducible when acquisition conditions were kept constant and the overall appearance of the profiles was well comparable. Peak areas of ten selected ion signals (9.5, 11.8, 14.0, 28.1, 43.4, 50.5, 60.1, 66.6, 74.5, and 79.8 kDa) from each spectrum were subjected to statistical analysis. Significant differences in ion intensities between the groups could be measured even without sample fractionation. The most striking difference between most of the spectra from HELLP patients and nonHELLP samples was the presence/absence of the 11.8 kDa ion signal (p-value: 0.0000365), most likely belonging to serum amyloid A (SAA). Other significant differences in ion intensities between HELLP and control samples were observed in the peak areas of the 14.0, 28.1, 50.5, and 74.5 kDa ion signals. Using the cryodetector MS data for sorting plasma samples into either the HELLP group (n = 8) or the nonHELLP group (n = 22), a sensitivity of 87.5% and a specificity of 100% were achieved. The positive predictive value of our screening assay was 100% and a negative predictive value of 95.6% was obtained with the samples included in this study.

Alteration of gene expression in macroscopically normal colonic mucosa from individuals with a family history of sporadic colon cancer

PURPOSE

We have shown that the expression of several genes associated with human colon cancer is altered in the morphologically normal colonic mucosa (MNCM) of APC(min) mice and humans with colon cancers. To determine whether these alterations also occur in the MNCM of individuals who have not developed colon cancer but are at high risk of doing so, we measured gene expression in the MNCM of individuals with a family history of colon cancer.

METHODS

Expression of 16 genes in the MNCM of 12 individuals with a first-degree relative with sporadic colon cancer and 16 normal controls were measured by quantitative reverse transcription-PCR. All subjects tested had normal colonoscopic examinations. Biopsy samples of MNCM were obtained from the ascending, transverse, descending, and rectosigmoid regions of the colon (2-8 biopsy samples were obtained from each region).

RESULTS

Relative to normal controls, the expression of several genes, including PPAR-gamma, SAA1, and IL-8 were significantly altered in the macroscopically normal rectosigmoid mucosa from individuals with a family history of colon cancer.

CONCLUSIONS

Molecular abnormalities that precede the appearance of adenomatous polyp are present in the MNCM of individuals who have a family history of colon cancer. This observation raises the possibility of screening for individuals who are at an increased risk of developing colon cancer by analysis of gene expression in rectosigmoid biopsy samples. To assess this possibility, prospective studies will be needed to determine whether or not altered gene expression is associated with the subsequent development of adenomatous polyps and/ or colonic carcinomas.

Presence of autoantibodies to apolipoprotein A-1 in patients with acute coronary syndrome further links autoimmunity to cardiovascular disease

Anti-apolipoprotein A-1 (Apo A-1) autoantibodies were described in autoimmune disorders such as systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) and might be involved in the genesis of arterial and venous thrombotic events. To investigate the presence of these autoantibodies in patients with acute coronary syndrome (ACS) without other features of autoimmunity, we set up an enzyme-linked immunosorbent assay (ELISA) for anti-Apo A-1 antibodies. We used it to investigate their prevalence in ACS as compared to SLE and APS and correlated them to plasma Apo A-1 and serum amyloid A protein (SAA) concentrations. The prevalence of anti-Apo A-1 autoantibodies in the healthy control group was 1% (1/92), but was significantly higher in other groups: 21% (11/53) in ACS group (P=0.001), 13% (12/92) in SLE and/or APS group (P=0.005). Multiple linear regression revealed a significant correlation between plasma Apo A-1 (r=-0.72, P=0.013), plasma SAA concentration (r=0.76, P=0.0066) and anti-Apo A-1 IgG titre in ACS patients. The presence of anti-Apo A-1 autoantibodies in patients with ACS highlights an additional link between autoimmunity, inflammation and atherosclerosis.

Urea-induced denaturation of apolipoprotein serum amyloid A reveals marginal stability of hexamer

Serum Amyloid A (SAA) is an acute phase reactant protein that is predominantly found bound to high-density lipoprotein in plasma. Upon inflammation, the plasma concentration of SAA can increase dramatically, occasionally leading to the development of amyloid A (AA) amyloidosis, which involves the deposition of SAA amyloid fibrils in major organs. We previously found that the murine isoform SAA2.2 exists in aqueous solution as a hexamer containing a central channel. Here we show using various biophysical and biochemical techniques that the SAA2.2 hexamer can be totally dissociated into monomer by approximately 2 M urea, with the concerted loss of its alpha-helical structure. However, limited trypsin proteolysis experiments in urea showed a conserved digestion profile, suggesting the preservation of major backbone topological features in the urea-denatured state of SAA2.2. The marginal stability of hexameric SAA2.2 and the presence of residual structure in the denatured monomeric protein suggest that both forms may interconvert in vivo to exert different functions to meet the various needs during normal physiological conditions and in response to inflammatory stimuli.

Potential genetic modifiers of the cystic fibrosis intestinal inflammatory phenotype on mouse chromosomes 1, 9, and 10

Background

Although cystic fibrosis is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, the severity of disease is highly variable indicating the influence of modifier genes. The intestines of Cftr deficient mice (CF mice: Cftr^tm1Unc) are prone to obstruction by excessive mucus accumulation and are used as a model of meconium ileus and distal intestinal obstruction syndrome. This phenotype is strongly dependent on the genetic background of the mice. On the C57Bl/6 background, the majority of CF mice cannot survive on solid mouse chow, have inflammation of the small intestine, and are about 30% smaller than wild type littermates. In this work potential modifier loci of the CF intestinal phenotype were identified.

Results

CF mice on a mixed genetic background (95% C57Bl/6 and 5% 129Sv) were compared to CF mice congenic on the C57Bl/6 background for several parameters of the intestinal CF phenotype. CF mice on the mixed background exhibit significantly greater survival when fed dry mouse chow, have reduced intestinal inflammation as measured by quantitative RT-PCR for marker genes, have near normal body weight gain, and have reduced mucus accumulation in the intestinal crypts. There was an indication of a gender effect for body weight gain: males did not show a significant improvement at 4 weeks of age, but were of normal weight at 8 weeks, while females showed improvement at both 4 and 8 weeks. By a preliminary genome-wide PCR allele scanning, three regions were found to be potentially associated with the milder phenotype. One on chr.1, defined by marker D1Mit36, one on chr. 9 defined by marker D9Mit90, and one on chr. 10, defined by marker D10Mit14.

Conclusion

Potential modifier regions were found that have a positive impact on the inflammatory phenotype of the CF mouse small intestine and animal survival. Identification of polymorphisms in specific genes in these regions should provide important new information about genetic modifiers of the CF intestinal phenotype.

Synergy between deacetylase inhibitors and IL-1beta in activation of the serum amyloid A2 gene promoter

Butyrate (NaBu) regulates intestinal inflammatory gene expression in part through inhibition of deacetylase activity, but the exact mechanisms involved remain to be determined. In this study, we showed by Northern blot a synergistic induction of the acute phase protein gene SAA2 with a combination of deacetylase inhibitors (Trichostatin A or NaBu) and IL-1beta in the colon carcinoma cell line Caco-2. While the NF-kappa B DNA-binding site was essential for SAA2 regulation by IL-1beta and deacetylase inhibitors, the C/EBP DNA-binding site modulated SAA2 expression levels, as assessed by transient transfection assays and mutagenesis studies. NaBu was sufficient to induce SAA2 expression after transient treatment with IL-1beta and, conversely, IL-1beta induced SAA2 after transient treatment with NaBu. These data suggest that pretreatment with either NaBu or IL-1beta predisposes the SAA2 promoter to further stimulation. Indeed, both NaBu and IL-1beta led to increased recruitment of NF-kappa B p65, C/EBPbeta, and C/EBP delta, and decreased NF-kappa B p50 and C/EBP alpha DNA-binding to the proximal SAA2 promoter, as assessed by chromatin immunoprecipitation assays. Interestingly, while IL-1beta, in contrast to NaBu, induced histone H4 acetylation, addition of IL-1beta and NaBu increased histone H4 acetylation and both C/EBPbeta and NF-kappa B p65 DNA-binding. Therefore, these results suggest that NaBu and IL- 1beta mediate SAA2 synergistic induction by establishing and maintaining similar and complementary chromatin modifications and transcription factor recruitment as well. In addition to global effects, NaBu specifically regulate gene expression, as exemplified by SAA2.

Serum amyloid A activates NF-kappaB and proinflammatory gene expression in human and murine intestinal epithelial cells

Serum amyloid A (SAA) is an acute-phase protein whose levels positively correlate with disease activity in inflammatory bowel diseases. In this study we investigated the impact of SAA on NF-kappaB signaling and proinflammatory gene expression in intestinal epithelial cells (IEC). Human HT-29 and Caco-2 monolayers were stimulated with recombinant SAA and NF-kappaB activation/NF-kappaB-dependent gene expression measured. Adenoviral dominant negative mutants IkappaB-alpha (Ad5IkappaBAA) were utilized to determine the contribution of NF-kappaB signaling pathway to SAA-dependent gene expression. Intestinal explant and primary IEC derived from kappaB-EGFP transgenic mice were exposed to SAA and NF-kappaB-dependent enhanced green fluorescent protein (EGFP) fluorescence measured. SAA induced IkappaB-alpha degradation, RelA serine 536 (S536) phosphorylation, NF-kappaB transcriptional activity, RelA recruitment to the IL-8 gene promoter and endogenous gene expression (IL-8, COX-2) in HT-29 cells. Further, Ad5IkappaBAA abrogated SAA-induced RelA nuclear translocation, NF-kappaB transcriptional activity and IL-8 gene expression. SAA-dependent IL-8 gene expression required activation of the MAPK ERK, p38 and JNK in HT-29 cells. Finally, SAA induced EGFP expression in intestinal explants isolated from kappaB-EGFP transgenic mice and enhanced RelA and IkappaBalpha phosphorylation in primary IEC. This indicates that SAA potentially participate in the inflammatory process by virtue of its ability to activate proinflammatory signaling in IEC.

The effects of vitamin A, pentoxyfylline and methylprednisolone on experimentally induced amyloid arthropathy in brown layer chicks

The effects of vitamin A, pentoxyfylline and methylprednisolone on experimentally induced amyloid arthropathy were investigated. In this study, 175 1-day-old brown layer chicks were used. Throughout the study Group II (vitamin A) received high doses of vitamin A (75,000 IU/kg), whereas Group I (negative control), Group III (positive control), Group IV (pentoxyfylline) and Group V (methylprednisolone) received normal levels of vitamin A in the diet. At the fifth week, the experimental Groups II, III, IV and V were injected with Freund's adjuvant intra-articularly to induce amyloid arthropathy. Group IV received pentoxyfylline and Group V received methylprednisolone (10 mg/kg, intramuscularly) once. Joint and blood samples were examined 13 weeks after the injections. The values in Groups I, II, III, IV and V, respectively, were as follows: amyloid arthropathy formation (%), 0, 100, 87, 76, 66; serum amyloid A (ng/ml), 166+/-17, 607+/-40, 423+/-39, 342+/-27, 293+/-22; serum retinol (microg/dl): 59.75+/-3.8, 42.72+/-3, 59.24+/-3.6, 102+/-9.1, 101.3+/-12.3; heterophil/lymphocyte ratio: 0.504, 0.75, 0.75, 0.087, 0.44. In conclusion, it was observed that vitamin A enhanced the development of amyloid arthropathy and there were positive associations between amyloidosis, increased levels of serum amyloid A and increased numbers of tissue infiltrating macrophages. Methylprednisolone had a more successful inhibitory effect on amyloid arthropathy than pentoxyfylline.

Acute phase reactants in allergic airway disease

Acute phase reactants have been implicated for their involvement as proinflammatory molecules in various inflammatory diseases. However, little is known regarding their role in the allergic airway disease. The aim of the present study was to examine the blood concentrations of three acute-phase proteins, namely C-reactive protein (CRP), serum amyloid A (SAA) and fibrinogen in patients with allergic rhinitis and asthma. Three study groups include: non-smoker allergic rhinitis (n = 50), non-smoker asthma (n = 20), and non-allergic, non-smoker healthy control subjects (n = 20). Patients who have had recent upper or lower respiratory tract infection and trauma, any rheumatological illnesses, malignancy or obesity were excluded. Blood samples were obtained from all the patients and control subjects and were analyzed for serum CRP, SAA and plasma fibrinogen. The mean CRP and fibrinogen values in the rhinitis and asthma groups were not significantly different when compared to the control group. However, the mean SAA levels of both groups were found to be significantly higher than those of the control group (p = 0.002 for rhinitis, p = 0.02 for asthma). There was no significant correlation between the FEV(1) values and the levels of the serum markers. This study demonstrates that acute phase reactant SAA rises in patients with allergic rhinitis and patients with asthma. We therefore suggest that SAA may have a role in the inflammatory airway disease.

Serum amyloid A: production by human white adipocyte and regulation by obesity and nutrition

AIMS/HYPOTHESIS

The acute-phase proteins, serum amyloid As (SAA), are precursors of amyloid A, involved in the pathogenesis of AA amyloidosis. This work started with the characterisation of systemic AA amyloidosis concurrent with SAA overexpression in the subcutaneous white adipose tissue (sWAT) of an obese patient with a leptin receptor deficiency. In the present study a series of histopathological, cellular and gene expression studies was performed to assess the importance of SAA in common obesity and its possible production by mature adipocytes.

MATERIALS AND METHODS

Gene expression profiling was performed in the sWAT of two extremely obese patients with a leptin receptor deficiency. Levels of the mRNAs of the different SAA isoforms were quantified in sWAT cellular fractions from lean subjects and from obese subjects before and after a very-low-calorie diet. These values were subsequently compared with serum levels of SAA in these individuals. In addition, histopathological analyses of sWAT were performed in lean and obese subjects.

RESULTS

In sWAT, the expression of SAA is more than 20-fold higher in mature adipocytes than in the cells of the stroma vascular fraction (p<0.01). Levels of SAA mRNA expression and circulating levels of the protein are sixfold (p<0.001) and 3.5-fold (p<0.01) higher in obese subjects than in lean subjects, respectively. In lean subjects, 5% of adipocytes are immunoreactive for SAA, whereas the corresponding value is greater than 20% in obese subjects. Caloric restriction results in decreases of 45-75% in levels of the transcripts for the SAA isoforms and in circulating levels of the protein.

CONCLUSIONS/INTERPRETATION

The results of the present study indicate that SAA is expressed by sWAT, and its production at this site is regulated by nutritional status. If amyloidosis is seen in the context of obesity, it is possible that production of SAA by adipocytes could be a contributory factor.

Hyperresponsiveness of neutrophils from gp 91phox deficient patients to lipopolysaccharide and serum amyloid A

We demonstrate here that neutrophils from chronic granulomatous disease (CGD) patients release larger amounts of interleukin-8 (IL-8) and tumor necrosis factor alpha (TNF-alpha) than neutrophils from control subjects. Incremental cytokine production was observed under both basal and stimulated conditions in neutrophils from two CGD (gp 91phox) patients. The basal production of IL-8 was over seven-fold greater in CGD patients. The two samples assayed showed 3- and 10-fold increases in TNF-alpha. Basically, the same magnitude of increment was observed in lypopolysaccharide (LPS) and serum amyloid A protein (SAA)-stimulated cells. We also found that the levels of SAA and IL-8 were higher in the serum of CGD patients than the levels found in the serum of healthy donors. The increased responsiveness of neutrophils from CGD patients may be closely related with a deficiency in the assembly of the nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase enzyme system, or it may be due to a frequent inflammatory condition in these patients. In the latter case, the increased serum levels of systemic inflammatory factors, among them SAA, would contribute to the sustained accumulation and activation of phagocytes. Whatever the origin, the excessive production of cytokines may lead to inappropriate activation and tissue injury and even to increased susceptibility to invasive microorganisms, impairing the quality life of CGD patients.

Identification of serum amyloid A as a biomarker to distinguish prostate cancer patients with bone lesions

BACKGROUND

Prostate cancer has a propensity to metastasize to the bone. Currently, there are no curative treatments for this stage of the disease. Sensitive biomarkers that can be monitored in the blood to indicate the presence or development of bone metastases and/or response to therapies are lacking. Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) is an affinity-based approach that allows sensitive and high-throughput protein profiling and screening of biological samples.

METHODS

We used SELDI-TOF MS for protein profiling of sera from prostate cancer patients (n = 38) with and without bone metastases in our effort to identify individual or multiple serum markers that may be of added benefit to those in current use. Serum was applied to ProteinChip surfaces (H4 and IMAC) to quickly screen samples and detect peaks predominating in the samples obtained from patients with bone metastases. Unique proteins in the bone metastasis cohort observed by SELDI-TOF MS were identified by two-dimensional gel electrophoresis, in-gel trypsin digestion, and tandem MS. The identities of the proteins were confirmed by ELISA and immunodepletion assays.

RESULTS

The cluster of unique proteins in the sera of patients with bone metastases was identified as isoforms of serum amyloid A. Machine-learning algorithms were also used to identify patients with bone metastases with a sensitivity and specificity of 89.5%.

CONCLUSIONS

SELDI-TOF MS protein profiling in combination with other proteomic approaches may provide diagnostic tools with potential clinical applications and serve as tools to aid in the discovery of biomarkers associated with various diseases.

Serum amyloid A binding to CLA-1 (CD36 and LIMPII analogous-1) mediates serum amyloid A protein-induced activation of ERK1/2 and p38 mitogen-activated protein kinases

Serum amyloid A protein (SAA) is an acute-phase reactant, known to mediate pro-inflammatory cellular responses. This study reports that CLA-1 (CD36 and LIMPII Analogous-1; human orthologue of the Scavenger Receptor Class B Type I (SR-BI)) mediates SAA uptake and downstream SAA signaling. Flow cytometry experiments revealed more than a 5-fold increase of Alexa-488 SAA uptake in HeLa cells stably transfected with CLA-1. Alexa 488-HDL uptake directly correlated with SAA uptake when determined in several CLA-1 stably transfected HeLa cell clones expressing various levels of CLA-1. SAA directly binds to CLA-1 as determined by cross-linking and colocalization of anti-CLA-1 antibody with SAA. SAA was co-internalized with transferrin to the endocytic recycling compartment pointing to a potential site of SAA metabolism. Alexa-488 SAA uptake in the CLA-1-overexpressing HeLa cells, as well as in THP-1 monocyte cell line, can be efficiently blocked by unlabeled SAA, high density lipoprotein, and other CLA-1 ligands. At the same time, markedly enhanced levels of phosphorylation of the mitogen-activated protein kinases (MAPKs), ERK1/2, and p38, were observed in cells stably transfected with CLA-1 cells following SAA stimulation when compared with mock transfected cells. The levels of the SAA-induced interleukin-8 (IL-8) secretion by CLA-1-overexpressing cells also significantly exceeded (5- to 10-fold) those detected for control cells. Synthetic amphipathic peptides possessing a structural alpha-helical motif inhibited SAA-induced activation of both MAPKs and IL-8 secretion in THP-1 cells. The results of this study demonstrate for the first time that CLA-1 functions as an endocytic SAA receptor and is involved in SAA-mediated cell signaling events associated with the immune-related and inflammatory effects of SAA.

Proteomic analysis of blood level of proteins before and after operation in patients with esophageal squamous cell carcinoma at high-incidence area in Henan Province

AIM: To characterize the protein files in blood from same patients with esophageal squamous cell carcinoma (ESCC) before and after operation at the high-incidence area for ESCC in Henan Province, China.

METHODS: Two-dimensional electrophoresis, silver staining and ImageMaster 2-DE analysis software were applied to the determination of protein files in the blood obtained from normal controls and ESCC patients before and after operation.

RESULTS: A total of 655, 662 and 677 protein spots were identified, respectively, from the normal controls and ESCC patients before and after operation. No significant difference in the number of protein spots was observed between the normal group and ESCC patients. A total of seven protein spots were identified with a dramatic difference among the samples before and after operation. Six protein spots were up-regulated and one protein spot was down-regulated in the group after operation compared with those in normal and before operation. Three protein spots were further characterized by matrix-assisted laser desorption/ionization time of flying mass spectrometry (MALDI-TOF-MS). The proteins from these three spots were identified as serum amyloid A (SAA), amyloid related serum protein and haptoglobin.

CONCLUSION: serum amyloid A, amyloid related serum protein and haptoglobin may be related with ESCC and/or surgery. The significance of these proteins needs to be further characterized. The present study provides informative data for the establishment of serum protein profiles related with ESCC.

Metabolic storage diseases: amyloidosis

This article provides an overview of the current concepts in pathogenesis, epidemiology, clinical significance, and treatment options for amyloidosis. Emphasis is given to hepatic amyloidosis, which ranges from a clinically insignificant histologic curiosity to a harbinger of widespread disease accompanied by a poor prognosis. Clinical characteristics and clues to the diagnosis are discussed as well as the importance of histologic confirmation and the controversy surrounding liver biopsy.