Bruton's tyrosine kinase expression and activity in X-linked agammaglobulinaemia (XLA): the use of protein analysis as a diagnostic indicator of XLA

Sea Cucumber Sterol Alleviates the Lipid Accumulation in High-Fat-Fructose Diet Fed Mice

The effect of marine-derived sea cucumber sterol (SS) with a special sulfate group on lipid accumulation remains unknown, although phytosterol has been proved to have many biological activities, including lowering blood cholesterol. The purpose of the present study is to investigate the alleviation of SS on lipid accumulation and the possible underlying mechanism using high-fat-fructose diet fed mice. Dietary administration with SS for 8 weeks reduced significantly the body weight gain and lipid levels in serum and liver. Especially, SS was superior to phytosterol in lowering lipid accumulation due to the great promotion of fatty acid β-oxidation, the inhibition of cholesterol synthesis, and the acceleration of cholesterol efflux. The findings found that sea cucumber sterol exhibited a more significant effect than phytosterol on alleviating HFF-diet-induced lipid accumulation through regulating lipid and cholesterol metabolism, which might be attributed to the difference in the branch chain and sulfate group.

Serum amyloid A (SAA) is an early biomarker of influenza virus disease in BALB/c, C57BL/2, Swiss-Webster, and DBA.2 mice

Assessment of influenza virus disease progression and efficacy of antiviral therapy in the widely used mouse models relies mostly on body weight loss and lung virus titers as markers of disease. However, both parameters have their shortcomings. Therefore, the aim of our study was to find non-invasive markers in the murine model of severe influenza that could detect disease early and predict disease outcome. BALB/c mice were lethally infected with influenza A(H1N1)pdm09 virus and serum samples were collected at various time points. Enzyme-linked immunosorbent assays were performed to quantify amounts of serum amyloid A (SAA), C-reactive protein, complement 3, transferrin, corticosterone, prostaglandin E2, H2O2, and alpha-2,6-sialyltransferase. We found that SAA was the most promising candidate with levels acutely and temporarily elevated by several hundred-fold 3 days post virus inoculation. Upon treatment with oseltamivir phosphate, levels of SAA were significantly decreased. High levels of SAA were associated with poor disease prognosis, whereas body weight loss was not as a reliable predictor of disease outcome. SAA levels were also transiently increased in BALB/c mice infected with influenza A(H3N2) and influenza B virus, as well as in C57BL/2, Swiss-Webster, and DBA.2 mice infected with influenza A(H1N1)pdm09 virus. High levels of SAA often, but not always, were associated with disease outcome in these other influenza virus mouse models. Therefore, SAA represents a valid biomarker for influenza disease detection in all tested mouse strains but its prognostic value is limited to BALB/c mice infected with influenza A(H1N1)pdm09 virus.

Inflammation-induced acute phase response in skeletal muscle and critical illness myopathy

Objectives

Systemic inflammation is a major risk factor for critical-illness myopathy (CIM) but its pathogenic role in muscle is uncertain. We observed that interleukin 6 (IL-6) and serum amyloid A1 (SAA1) expression was upregulated in muscle of critically ill patients. To test the relevance of these responses we assessed inflammation and acute-phase response at early and late time points in muscle of patients at risk for CIM.

Design

Prospective observational clinical study and prospective animal trial.

Setting

Two intensive care units (ICU) and research laboratory.

Patients/Subjects

33 patients with Sequential Organ Failure Assessment scores ≥8 on 3 consecutive days within 5 days in ICU were investigated. A subgroup analysis of 12 patients with, and 18 patients without CIM (non-CIM) was performed. Two consecutive biopsies from vastus lateralis were obtained at median days 5 and 15, early and late time points. Controls were 5 healthy subjects undergoing elective orthopedic surgery. A septic mouse model and cultured myoblasts were used for mechanistic analyses.

Measurements and Main Results

Early SAA1 expression was significantly higher in skeletal muscle of CIM compared to non-CIM patients. Immunohistochemistry showed SAA1 accumulations in muscle of CIM patients at the early time point, which resolved later. SAA1 expression was induced by IL-6 and tumor necrosis factor-alpha in human and mouse myocytes in vitro. Inflammation-induced muscular SAA1 accumulation was reproduced in a sepsis mouse model.

Conclusions

Skeletal muscle contributes to general inflammation and acute-phase response in CIM patients. Muscular SAA1 could be important for CIM pathogenesis.

Trial Registration

ISRCTN77569430.

Interplay of the inflammatory and stress systems in a hepatic cell line: interactions between glucocorticoid receptor agonists and interleukin-6

The liver plays an important role in inflammation and stress by producing the acute phase proteins (APPs) required for resolution of inflammation as well as by delivering systemic glucose, through gluconeogenesis, required to fuel the stress response. Disruption of the interplay between interleukin 6 (IL-6) and glucocorticoids (GCs), the peripheral mediators of inflammation and stress, respectively, may lead to side-effects associated with the pharmacological use of GCs. The current study investigated the interplay between IL-6 and GCs in a hepatoma cell line (BWTG3) at protein (protein activity assays, Western blotting, and ELISA) and mRNA (qPCR) levels. Specifically, the action of dexamethasone (Dex), a known antiinflammatory drug and glucocorticoid receptor (GR) agonist, is compared to that of Compound A (CpdA), a selective glucocorticoid receptor agonist (SEGRA). CpdA, like IL-6, but unlike Dex, increases GR binding and decreases the metabolic enzymes, tyrosine aminotransferase, phosphoenolpyruvate carboxykinase, and gamma glutamyltransferase, at protein or mRNA level. Like Dex, both CpdA and IL-6 increase the positive APPs, serum amyloid A and C-reactive protein, and decrease the negative APP, corticosteroid binding globulin. The study shows that the GC, Dex, and IL-6 generally have divergent effects on the GR and metabolic enzymes, while their functions are convergent on the APPs. In contrast to Dex, CpdA has effects convergent to that of IL-6 on the GR, metabolic enzymes, and APPs. Thus these findings suggest that CpdA, like Dex, modulates APPs, leading to effective control of inflammation, while, in contrast to Dex, it is less likely to lead to GC-induced side-effects.

Suppression of amyloidogenesis in a mouse model by corticosteroid intervention

Steroid treatment of amyloidosis was studied previously in human and murine models of reactive amyloidosis but with limited success and with conflicting results. To determine whether steroids may inhibit amyloidogenesis, and to study factors that may play a role in this effect, the authors induced amyloidosis in Swiss male mice, using the enhanced protocol with a single intravenous injection of amyloid-enhancing factor (AEF) and 3 successive daily subcutaneous AgNO(3) injections. Suppression of amyloid formation by various commonly used steroid preparations was evaluated from the amount of splenic amyloid, using the crush-and-smear technique. All steroid preparations examined were found to suppress amyloidogenesis but with differences between them in the degree and duration of inhibition. In general, hydrocortisone and dexamethasone had the highest suppressive effect, whereas methylprednisolone displayed lower activity for shorter duration. Single-dose experiments revealed that steroid effect is limited to the onset of amyloidogenesis. These experiments show that corticosteroids may significantly suppress amyloidogenesis but only briefly and, therefore, discourage a long-term and late use of steroid supplement in different anti-amyloid treatment protocols.

Reference maps of mouse serum acute-phase proteins: Changes with LPS-induced inflammation and apolipoprotein A-I and A-II transgenes

We present reference maps of the mouse serum proteome (run under reducing and non-reducing conditions), from control animals, from mice injected with lipopolysaccharide (LPS) to induce systemic inflammation, and from mice transgenic for human apolipoproteins A-I and A-II. Seventy-seven spots/spot chains from the reducing gels were identified by HPLC MS/MS, representing 28 distinct proteins, including a species-specific protease inhibitor, contrapsin, and high levels of carboxylesterase. The concentrations of acute-phase reactants were monitored for 96 h after LPS challenge. The greatest changes (four-fold 48 h after LPS administration) were observed for haptoglobin and hemopexin. Orosomucoid/alpha(1)-acid glycoprotein and apolipoprotein A-I increased steadily, to 50-60% above baseline at 96 h from stimulation. In mice transgenic for human apolipoprotein A-I the levels of expression of orosomucoid/alpha(1)-acid glycoprotein, alpha(1)-macroglobulin, esterase, kininogen and contrapsin were altered compared to knockout mice lacking apolipoprotein A-I. In contrast, except for the presence of apolipoprotein A-II, no statistically significant difference was observed in mice transgenic for human apolipoprotein A-II.

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.

Enrichment of serum amyloid proteins by hydrophobic interaction chromatography combined with two-dimensional electrophoresis with immobilised pH gradients

Serum amyloid A protein was subjected to one-step octyl-Sepharose extraction in three different dimensions. Elution was performed partly without UV recording, and with urea or guanidine-based buffers. The eluent was applied directly to denaturing two-dimensional electrophoresis with immobilised pH gradient, or octyl-Sepharose extracted fractions were pooled and lyophilised before application. Proteins were characterised by N-terminal analysis or mass spectrometry. In most of the species that were studied, previously undescribed serum amyloid proteins were detected. Compared to conventional strategies, the presented techniques are more rational and yield more comprehensive information. The presented data also provide a basis for novel perspectives regarding certain inflammatory conditions.

Analysis of Btk mutations in patients with X-linked agammaglobulinaemia (XLA) and determination of carrier status in normal female relatives: a nationwide study of Btk deficiency in Greece

Bruton's tyrosine kinase (Btk) is a nonreceptor tyrosine kinase, critical for B-cell development and function. Mutations that inactivate this kinase were found in families with X-linked agammaglobulinaemia (XLA). In this study the Btk gene was analyzed in 13 registered Greek patients with XLA phenotype originated from 12 unrelated families, in order to provide a definite diagnosis of the XLA. The structure of Btk was analyzed at the cDNA level using the recently developed method, NIRCA (Non-Isotopic-Rnase-Cleavage-Assay). Alterations were detected in all patients and sequencing analysis confirmed the results and defined six novel XLA-associated Btk mutations (three missense mutations: C337G, L346R, L452P; one nonsense mutation: Y392X, and two frameshift alterations: c1211-1212delA, c1306-1307insA). Having defined the genetic alteration in the affected males of these families, the information was used to design polymerase chain reaction (PCR) primers and the Btk segments containing the mutated sequences were amplified from peripheral blood derived genomic DNA of potential female carriers. The PCR products were directly sequenced and carrier status was determined in 12 out of 16 phenotypically normal females analyzed. This protocol can be used once the nature of the Btk mutation has been defined in one of the affected males and provides a convenient, simple and reliable way to determine the carrier status of other female family members. Molecular genetic analysis constitutes a determinative tool for the definitive diagnosis of XLA and may allow accurate carrier and prenatal diagnosis for genetic counselling.

Rapid protein-based assays for the diagnosis of T-B+ severe combined immunodeficiency

The severe combined immunodeficiencies (SCID) are a heterogeneous group of conditions arising from a variety of molecular defects. The X-linked form of SCID (X-SCID) is caused by defects in the common gamma chain (gammac), and is characterized by a T-B+NK- immunophenotype. This lymphocyte profile is seen in an autosomal recessive form of SCID caused by mutations in the JAK3 molecule. Thus, X-SCID and JAK3-deficient SCID are clinically and immunologically indistinguishable. Knowledge of the precise molecular defect is essential for antenatal diagnosis, carrier testing and for treatment using somatic gene therapy. To identify the molecular defect in children presenting with a T-B+NK- form of SCID, we have developed rapid assays based on flow cytometric analysis of gammac, immunoblotting for JAK3 and gammac, and detection of interleukin-2 (IL-2)-induced tyrosine phosphorylation of JAK3. Sixteen T-B+NK- SCID patients from 15 families were examined. Nine had no detectable gammac, four had abnormal gammac expression and no IL-2-induced JAK3 tyrosine phosphorylation, and one had normal gammac expression but no IL-2-induced JAK3 tyrosine phosphorylation, although JAK3 was present. All these patients had mutations identified in their gammac gene. Two patients exhibited normal gammac expression, but JAK3 was not detected by immunoblotting and these patients were confirmed as having JAK3 gene mutations. Thus, these protein-based assays have led to rapid molecular diagnoses in T-B+ SCID that have subsequently been confirmed by genetic analysis.

Serum amyloid A, the major vertebrate acute-phase reactant

The serum amyloid A (SAA) family comprises a number of differentially expressed apolipoproteins, acute-phase SAAs (A-SAAs) and constitutive SAAs (C-SAAs). A-SAAs are major acute-phase reactants, the in vivo concentrations of which increase by as much as 1000-fold during inflammation. A-SAA mRNAs or proteins have been identified in all vertebrates investigated to date and are highly conserved. In contrast, C-SAAs are induced minimally, if at all, during the acute-phase response and have only been found in human and mouse. Although the liver is the primary site of synthesis of both A-SAA and C-SAA, extrahepatic production has been reported for most family members in most of the mammalian species studied. In vitro, the dramatic induction of A-SAA mRNA in response to pro-inflammatory stimuli is due largely to the synergistic effects of cytokine signaling pathways, principally those of the interleukin-1 and interleukin-6 type cytokines. This induction can be enhanced by glucocorticoids. Studies of the A-SAA promoters in several mammalian species have identified a range of transcription factors that are variously involved in defining both cytokine responsiveness and cell specificity. These include NF-kappaB, C/EBP, YY1, AP-2, SAF and Sp1. A-SAA is also post-transcriptionally regulated. Although the precise role of A-SAA in host defense during inflammation has not been defined, many potential clinically important functions have been proposed for individual SAA family members. These include involvement in lipid metabolism/transport, induction of extracellular-matrix-degrading enzymes, and chemotactic recruitment of inflammatory cells to sites of inflammation. A-SAA is potentially involved in the pathogenesis of several chronic inflammatory diseases: it is the precursor of the amyloid A protein deposited in amyloid A amyloidosis, and it has also been implicated in the pathogenesis of atheroscelerosis and rheumatoid arthritis.