30-kD Protein Research Articles

Calcium/calmodulin-dependent protein kinase IV involvement in the pathophysiology of glucotoxicity in rat pancreatic β-cells

Glucotoxicity is a critical component of the pathophysiology of type 2 diabetes mellitus; however, the molecular mechanisms of glucotoxicity are still not fully understood. We have attempted to determine the protein kinases involved in glucotoxicity in pancreatic β-cells by the use of a new technique. Using Multi-PK antibodies, which are capable of detecting a wide variety of protein kinases, we analyzed the protein kinase that correlated with insulin synthesis in INS-1 cells under glucotoxic conditions. When expression patterns of protein kinases in INS-1 cells were analyzed by Western blotting with Multi-PK antibodies, a kinase of 63 kd was significantly reduced concomitant with the decrease of insulin secretion under glucotoxic conditions. To identify the 63-kd kinase, we used a unique 2-dimensional gel electrophoretic technique and MicroRotofor (Bio-Rad Laboratories, Tokyo, Japan) electrophoresis. From the molecular size of a native kinase/cyanogen bromide fragment and pI value, the 63-kd protein kinase was deduced to be CaMKIV. This was confirmed by Western blotting analysis using anti-CaMKIV antibodies. The decreased CaMKIV levels under glucotoxic conditions recovered to original levels after changing the medium to a normal glucose concentration. Recombinant CaMKIV was degraded in a Ca2+-dependent manner by incubation with cell lysates from INS-1 cells under glucotoxic conditions, and degradation was protected by calpain inhibitor. Furthermore, CaMKIV was reduced in the pancreatic islets of diabetic Otsuka Long-Evans Tokushima fatty rats, whereas that of nondiabetic Long-Evans Tokushima Otsuka rats was not. This study suggests that the abnormal regulation of CaMKIV is a component of β-cell dysfunction caused by high glucose.

Increased expression of interleukin‐7 in labial salivary glands of patients with primary Sjögren's syndrome correlates with increased inflammation

To study the expression levels and immunostimulatory capacities of interleukin-7 (IL-7) in primary Sjögren's syndrome. Labial salivary gland (LSG) IL-7 expression was determined by immunohistochemistry, using a quantitative scoring system, in 30 patients with sicca syndrome: 15 patients with primary Sjögren's syndrome (SS) and 15 patients with non-SS sicca syndrome. The correlation of IL-7 expression in LSGs with parameters of local and peripheral disease was studied, and serum and salivary IL-7 levels were determined. Additionally, the effects of IL-7 on cytokine production by peripheral blood mononuclear cells (PBMCs) from patients with primary SS were determined in vitro by Luminex multicytokine assay and compared with the effects in control subjects. The expression of IL-7 in LSGs was higher in patients with primary SS compared with that in patients with non-SS sicca syndrome. IL-7 was observed primarily in the vicinity of lymphocytic infiltrates. Salivary IL-7 levels in patients with primary SS were higher than those in control subjects. In all 30 patients with sicca syndrome, IL-7 expression in LSGs correlated with parameters of both local and peripheral disease. Furthermore, IL-7 stimulated T cell-attracting and T cell-differentiating cytokines (monokine induced by interferon-gamma [IFNgamma], IFNgamma-inducible 10-kd protein, IL-12, and IL-15), as well as Th1 (IFNgamma), Th2 (IL-4), Th17 (IL-17A), proinflammatory (tumor necrosis factor alpha and IL-1alpha), and regulatory (IL-10 and IL-13) cytokine production by PBMCs. All of these cytokines were previously shown to be associated with primary SS. The IL-7-induced increase in IL-10 production in patients with primary SS was reduced compared with that in control subjects. The correlation between LSG IL-7 expression and (local) disease parameters in primary SS as well as the IL-7-mediated induction of inflammatory cytokines indicate that IL-7 might contribute to the immunopathology of primary SS.

The Coiled-Coil Protein VIG1 Is Essential for Tethering Vacuoles to Mitochondria during Vacuole Inheritance ofCyanidioschyzon merolae

Vacuoles/lysosomes function in endocytosis and in storage and digestion of metabolites. These organelles are inherited by the daughter cells in eukaryotes. However, the mechanisms of this inheritance are poorly understood because the cells contain multiple vacuoles that behave randomly. The primitive red alga Cyanidioschyzon merolae has a minimum set of organelles. Here, we show that C. merolae contains about four vacuoles that are distributed equally between the daughter cells by binding to dividing mitochondria. Binding is mediated by VIG1, a 30-kD coiled-coil protein identified by microarray analyses and immunological assays. VIG1 appears on the surface of free vacuoles in the cytosol and then tethers the vacuoles to the mitochondria. The vacuoles are released from the mitochondrion in the daughter cells following VIG1 digestion. Suppression of VIG1 by antisense RNA disrupted the migration of vacuoles. Thus, VIG1 is essential for tethering vacuoles to mitochondria during vacuole inheritance in C. merolae.

Neutrophil Gelatinase-Associated Lipocalin Levels in Patients With Crohn Disease Undergoing Treatment With Infliximab

Increased levels of neutrophil gelatinase-associated lipocalin (NGAL), a small 25-kd stress protein released by several injured cells, have been reported in different pathological conditions such as kidney and chronic inflammatory...

Hepatitis B virus X protein upregulates tumor necrosis factor-α expression of rat mesangial cell line via ERKs pathway

Hepatitis B virus X protein (HBx), a 17-kd protein encoded by X gene of hepatitis B virus (HBV), has been shown to function as a transcriptional trans-activator of a variety of viral and cellular promoter/enhancer elements. The aim of the study is to investigate the extracellular regulated protein kinases (ERKs) pathway of HBx on glomerular mesangial cell (GMC) proliferation and tumor necrosis factor-α (TNF-α) expression. The HBV X gene was amplified by polymerase chain reaction (PCR), inserted into the eukaryotic expression vector pCI-neo and confirmed by restriction endonuclease digestion and sequence analysis. PCI-neo containing HBV X gene (pCI-neo-X) was then transfected into cultured GMC line via liposome. GMC proliferation, TNF-α and its mRNA expression were compared in the condition of with or without U0126 in culture media. HBx, ERK1/2 and p-ERK1/2 expression in GMCs was assessed by Western blotting. TNF-α mRNA expression was assessed by semiquantitative reverse transcription-PCR (RT-PCR). TNF-α level in supernatants was measured by ELISA. GMC proliferation was detected by 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) kit. The results showed that HBx expression was found in transfected GMCs and became prominent at 36th and 48th h after transfection whether with or without U0126 in culture media. TNF-α mRNA expression was significantly decreased in U0126 group compared with U0126-free group. TNF-α levels in supernatants in PCI-neo-X transfection without U0126 group were (189.0±18.1) and (172.3±24.3) pg/mL at 36th and 48th h after transfection, respectively. In contrast, TNF-α levels in supernatants with U0126 were (65.6±11.6) and (84.0±24.6) pg/mL at 36th and 48th h, respectively. The TNF-α levels in the latter groups were significantly lower than those in the former groups (P < 0.05). GMCs proliferation was also lower in added U0126 group at 36th and 48th h after transfection. From above, we can conclude that HBx could induce GMC proliferation and increase TNF-α mRNA expression and its protein production. HBx upregulates TNF-α expression and induces cell proliferation of GMC line partly through ERK1/2 signal transduction pathway.

Endoplasmic reticulum-localized small heat shock protein that accumulates in mulberry tree (Morus bombycis Koidz.) during seasonal cold acclimation is responsive to abscisic acid

With seasonal changes, several proteins accumulate in the endoplasmic reticulum (ER)-enriched fraction in the bark of mulberry tree (Morus bombycis Koidz.). Results of partial amino acid sequence analysis in our previous study suggested that one of these proteins is the ER-localized small heat shock protein (sHSP), designated 20-kD winter-accumulating protein (WAP20). In the present study, molecular and biochemical properties of WAP20 were investigated in detail. The deduced amino acid sequence of the cDNA has the predicted signal sequence to the ER, retention signal to the ER and two consensus regions conserved in sHSPs. Recombinant WAP20 expressed in Escherichia coli also showed typical biochemical features of sHSPs, including the formation of a high-molecular-mass complex between 200 and 300 kD under native conditions, promotion of the renaturation of chemically denaturated citrate synthase and prevention of heat stress-induced aggregation of the enzyme. Transcript levels of WAP20 in the bark tissue were seasonally changed, showing high expression levels from mid-October to mid-December, and the transcript levels were additionally increased and decreased by cold treatment and warm treatment, respectively. WAP20 transcripts were detected abundantly in bark tissue rather than xylem and winter bud tissues during seasonal cold acclimation. The bark tissue specificity of WAP20 accumulation was also observed by exogenous application of phytohormone abscisic acid (ABA) in de-acclimated twigs, whereas WAP20 transcripts were increased in all of these tissues by heat shock treatment at 37 degrees C in summer twigs. The results suggest that ABA may be involved in the expression of the WAP20 gene in bark tissue of the mulberry tree during seasonal cold acclimation.

Clara Cell 10-kD Protein Suppresses Chitinase 3-Like 1 Expression Associated with Eosinophilic Chronic Rhinosinusitis

Clara cell 10-kD (CC10) protein, an antiinflammatory molecule, is involved in inflammatory upper airway diseases, but its regulatory role is unclear, particularly in the process of chronic rhinosinusitis (CRS). To investigate the regulatory mechanisms of CC10 in eosinophilic CRS (ECRS) using an allergic mouse model. Homozygous CC10-knockout mice were used to establish an allergic ECRS model. Phenotypic changes were examined by histology, cytokine ELISA, and gene microarray analysis. Differential expression of chitinase 3-like 1 (CHI3L1) was verified by quantitative reverse transcriptase-polymerase chain reaction and immunohistochemistry. The functional role of CHI3L1 in vivo was assessed by the use of anti-CHI3L1 antibody in ECRS mice. CHI3L1 gene expression regulated by inflammatory cytokines and CC10 protein was performed using BEAS-2B cell line. Compared with wild-type mice, a significantly greater extent of inflammatory cell infiltration and tissue remodeling was found in CC10-knockout ECRS mice, which was associated with significantly higher levels of various cytokines and eotaxin-1. CHI3L1 was up-regulated in ECRS mice with a significant further increase in CC10-knockout mice. Anti-CHI3L1 treatment markedly ameliorated eosinophilic inflammation. Furthermore, nasal mucosal CC10 gene transfer in CC10-knockout mice attenuated eosinophilic inflammation and suppressed the levels of CHI3L1. Moreover, significantly up-regulated expression of CHI3L1 was noted in human ECRS. IL-1beta, tumor necrosis factor-alpha, and IL-13 were found to up-regulate CHI3L1 expression in BEAS-2B cells, whereas CC10 inhibited such up-regulation. These results suggest that CHI3L1 is a novel molecule involved in ECRS and that CC10 plays a regulatory role in ECRS, presumably by attenuating CHI3L1 expression.

Rational Design of Acidic Human Fibroblast Growth Factor (hFGF-1) with Increased Stability and Mitogenic Activity

Human acidic fibroblast growth factor (hFGF-1) belongs to a superfamily of 22 fibroblast growth factors (FGFs) that have a high affinity to heparin. It is a 16kD protein, which is involved in many cellular functions, such as, cell proliferation, cell differentiation, angiogenesis, tumor growth, and wound healing. In wound healing, the blood coagulation cascade is triggered to clog the wound. One of the proteases that participates in wound healing is thrombin, which converts fibrinogen to fibrin. Thrombin also cleaves wild type hFGF-1 and consequently decreases its wound healing potency. Thrombin is shown to specifically cleave FGF-1 at Arg136. In this context, in the present study we have designed several site-directed mutants at Arg136 to understand the role of this residue not only on the stability of FGF-1 but also on the FGF signaling process. The results of this study will be discussed in detail.

Reduced Viability of Mice with Lung Epithelial-Specific Knockout of Glucocorticoid Receptor

Glucocorticoid (GC)-responsive epithelial-mesenchymal interactions regulate lung development. The GC receptor (GR) mediates GC signaling. Mice lacking GR in all tissues die at birth of respiratory failure. To determine the specific need for epithelial GR in lung development, we bred triple transgenic mice that carry SPC/rtTA, tet-O-Cre, and floxed, but not wild-type, GR genes. When exposed to doxycycline in utero, triple transgenic (GRepi⁻) mice exhibit a Cre-mediated recombination event that inactivates the floxed GR gene in airway epithelial cells. Immunofluorescence confirmed the elimination of GR in Cre-positive airway epithelial cells of late gestation GRepi⁻ mice. Embryonic Day 18.5 pups had a relatively immature appearance with increased lung cellularity and increased pools of glycogen in the epithelium. Postnatal Day 0.5 pups had decreased viability. We used quantitative RT-PCR to demonstrate that specific elimination of epithelial immunoreactive GR in GRepi⁻ mice is associated with reduced mRNA expression for surfactant proteins (SPs) A, B, C, and D; β- and γ-ENaC; T1α; the 10-kD Clara cell protein (CCSP); and aquaporin 5 (AQP5). Western blots confirmed reduced levels of AQP5 protein. No reduction in the levels of the GR transport protein importin (IPO)-13 was observed. Our findings demonstrate a requirement for lung epithelial cell GR in normal lung development. We speculate that impaired epithelial differentiation, leading to decreased SPs, transepithelial Na, and liquid absorption at birth, may contribute to the reduced survival of newborn mice with suppressed lung epithelial GR.

Interleukin‐6 and type I interferon–regulated genes and chemokines mark disease activity in dermatomyositis

Up-regulation of whole blood type I interferon (IFN)-driven transcripts and chemokines has been described in a number of autoimmune diseases. An IFN gene expression "signature" is a candidate biomarker in patients with dermatomyositis (DM). This study was performed to evaluate the capacity of IFN-dependent peripheral blood gene and chemokine signatures and levels of proinflammatory cytokines to serve as biomarkers for disease activity in adult and juvenile DM. Peripheral blood samples and clinical data were obtained from 56 patients with adult or juvenile DM. The type I IFN gene signature in the whole blood of patients with DM was defined by determining the expression levels of 3 IFN-regulated genes (IFIT1, G1P2, and IRF7) using quantitative real-time reverse transcription-polymerase chain reaction. Multiplexed immunoassays were used to quantify the serum levels of 4 type I IFN-regulated chemokines (IFN-inducible T cell alpha chemoattractant, IFNgamma-inducible 10-kd protein, monocyte chemotactic protein 1 [MCP-1], and MCP-2) and the serum levels of other proinflammatory cytokines, including interleukin-6 (IL-6). DM disease activity correlated significantly with the type I IFN gene signature (r = 0.41, P = 0.007) and with the type I IFN chemokine signature (r = 0.61, P < 0.0001). Furthermore, the serum levels of IL-6 were significantly correlated with disease activity (r = 0.45, P = 0.001). In addition, correlations between the serum levels of IL-6 and both the type I IFN gene signature (r = 0.47, P < 0.01) and the type I IFN chemokine signature (r = 0.71, P < 0.0001) were detected in patients with DM. These results suggest that serum IL-6 production and the type I IFN gene signature are candidate biomarkers for disease activity in adult and juvenile DM. Coregulation of the expression of IFN-driven chemokines and IL-6 suggests a novel pathogenic linkage in DM.

Interferon‐regulated chemokines as biomarkers of systemic lupus erythematosus disease activity: A validation study

Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by unpredictable flares of disease activity and irreversible damage to multiple organ systems. An earlier study showed that SLE patients carrying an interferon (IFN) gene expression signature in blood have elevated serum levels of IFN-regulated chemokines. These chemokines were associated with more-severe and active disease and showed promise as SLE disease activity biomarkers. This study was designed to validate IFN-regulated chemokines as biomarkers of SLE disease activity in 267 SLE patients followed up longitudinally. To validate the potential utility of serum chemokine levels as biomarkers of disease activity, we measured serum levels of CXCL10 (IFNgamma-inducible 10-kd protein), CCL2 (monocyte chemotactic protein 1), and CCL19 (macrophage inflammatory protein 3beta) in an independent cohort of 267 SLE patients followed up longitudinally over 1 year (1,166 total clinic visits). Serum chemokine levels correlated with lupus activity at the current visit (P = 2 x 10(-10)), rising at the time of SLE flare (P = 2 x 10(-3)) and decreasing as disease remitted (P = 1 x 10(-3)); they also performed better than the currently available laboratory tests. Chemokine levels measured at a single baseline visit in patients with a Systemic Lupus Erythematosus Disease Activity Index of < or =4 were predictive of lupus flare over the ensuing year (P = 1 x 10(-4)). Monitoring serum chemokine levels in SLE may improve the assessment of current disease activity, the prediction of future disease flares, and the overall clinical decision-making.

Identification of crab proteins that elicit IgE reactivity in snow crab–processing workers

The expanding snow crab-processing industry has resulted in increased numbers of workers at risk of occupational allergy. Our study is to identify relevant allergenic proteins in cooked snow crab meat (CM) and crab water (CW) used for cooking for improved remediation, diagnosis, and treatment. Extracts were prepared from CM extracts, CW extracts, and an air-filter collection near the crab cooker. Of the 207 workers, 24 with the highest IgE antibody reactivity to CM and CW extracts, as determined by using RASTs, were tested for reactivity to nitrocellulose membranes containing CM and CW proteins separated with SDS-PAGE. A 3-serum pool was similarly incubated against nitrocellulose-bound proteins from air samples collected near the crab cooker. Of the 207 sera tested, 27 and 39 sera exhibited positive IgE antibody reactivity (>or=2%) to CM and CW extracts, respectively. Twenty-two of 24 sera with the highest RAST activity (>or=3.5% binding) demonstrated IgE binding to multiple proteins (13.6-50 kd). A majority of the sera reacted to 4 proteins: 79% and 71% to a 34.0-kd protein, 79% and 42% to a 25-kd protein, 67% and 71% to an 18.5-kd protein, and 75% to a 14.4-kd protein in both CM and CW extracts, respectively. The pool of IgE-positive sera blotted against the air-filter extract reacted to 14.4-, 18.5-, 34.0-, 43.2-, and 50-kd proteins present in both crab extracts. Four major IgE-reactive proteins were identified in CM extracts, CW extracts, and air-filter eluate. Analysis of any potential association of protein reactivity with disease suggested crab proteins at 34.0 and 14.4 kd might be more relevant.

BT2, a BTB Protein, Mediates Multiple Responses to Nutrients, Stresses, and Hormones in Arabidopsis

The Arabidopsis (Arabidopsis thaliana) gene BT2 encodes a 41-kD protein that possesses an amino-terminal BTB domain, a central TAZ domain, and a carboxyl-terminal calmodulin-binding domain. We previously demonstrated that BT2 could activate telomerase expression in mature Arabidopsis leaves. Here, we report its distinct role in mediating diverse hormone, stress, and metabolic responses. We serendipitously discovered that steady-state expression of BT2 mRNA was regulated diurnally and controlled by the circadian clock, with maximum expression in the dark. This pattern of expression suggested that BT2 mRNA could be linked to the availability of photosynthate in the plant. Exogenous sugars decreased BT2 expression, whereas exogenous nitrogen increased expression. bt2 loss-of-function mutants displayed a hypersensitive response to both sugar-mediated inhibition of germination and abscisic acid (ABA)-mediated inhibition of germination, thus supporting a role of ABA in sugar signaling in germination and development. Moreover, constitutive expression of BT2 imparted resistance to both sugars and ABA at germination, suggesting that BT2 suppresses sugar and ABA responses. In support of the previously described antagonistic relationship between ABA and auxin, we found that BT2 positively regulated certain auxin responses in plants, as revealed by knocking down BT2 expression in the high-auxin mutant yucca. Accumulation of BT2 mRNA was affected by a variety of hormones, nutrients, and stresses, and BT2 was required for responses to many of these same factors. Together, these results suggest that BT2 is a central component of an interconnected signaling network that detects and responds to multiple inputs.

Sarcoplasmic calcium-binding protein is an EF-hand–type protein identified as a new shrimp allergen

Shellfish allergy is a long-lasting disorder usually persisting throughout life. Despite its high prevalence, there is limited information about allergenic shrimp proteins. Characterization of shrimp allergens. Fifty-two adults and children with a history of immediate allergic reactions to shrimp and elevated serum IgE to shrimp were selected for this study. Tryptic digests from a 20-kd IgE-binding protein were analyzed by LC-MS/MS, identifying the protein as a sarcoplasmic-calcium-binding protein. cDNA encoding sarcoplasmic calcium-binding protein (SCP) from a shrimp cDNA library (Litopenaeus vannamei) was amplified by PCR, cloned into an expression vector, and sequenced. Recombinant SCP was tested with patients' sera. ELISA inhibition experiments determined the fraction of total shrimp IgE recognizing SCP. A functional assay with a rat basophilic leukemia cell line was used to determine the capacity for mediator release induced by SCP. Immunoblotting demonstrated IgE binding by 31 of 52 (59.6%) of the sera to a 20-kd shrimp protein. The protein was identified as a SCP. Amplified cDNA encoding SCP was isolated and sequenced. Open reading frame translation provided the complete amino acid sequence of shrimp SCP. Recombinant SCP was recognized by serum IgE from 20 of 52 (38.4%) subjects, of whom 17 of 20 (85%) were children. ELISA inhibition of pooled sera IgE reactivity to BS extract using recombinant SCP was significant (as high as 79%). For some subjects, mediator release induced by recombinant SCP was higher than that induced by recombinant tropomyosin. We have identified and cloned a new shrimp allergen, Lit v 4.0101, an SCP, which appears to be of particular importance in the pediatric population.

Activation of the interferon‐γ signaling pathway in systemic lupus erythematosus peripheral blood mononuclear cells

To investigate interferon-gamma (IFNgamma) signaling in peripheral blood mononuclear cells (PBMCs) from patients with systemic lupus erythematosus (SLE) by analyzing IFNgamma receptor (IFNgammaR) expression, STAT-1 expression and phosphorylation, and the regulation of IFNgamma-inducible genes. Fluorocytometry was used to investigate expression of STAT-1, pSTAT-1, CD95, HLA-DR, class I major histocompatibility complex (MHC), IFNgamma-inducible 10-kd protein (IP-10), monokine induced by IFNgamma (Mig), and IFNgammaR in PBMCs from SLE patients and healthy individuals. STAT-1 phosphorylation was determined by fluorocytometry and Western blotting after stimulation with IFNalpha or IFNgamma. Quantitative polymerase chain reaction was used to assess messenger RNA (mRNA) expression of the IFNgamma-inducible genes IP-10 and Mig shortly after preparation or after stimulation with IFNgamma in monocytes. STAT-1 expression was increased in PBMCs from SLE patients and correlated significantly with disease activity and with the IFN-inducible expression of CD95 and HLA-DR. STAT-1 expression also showed a trend toward association with class I MHC expression. In addition, the expression of other IFNgamma-inducible genes, such as IP-10 or Mig, was increased in SLE monocytes. While STAT-1 phosphorylation in SLE PBMCs and PBMCs from healthy individuals was similar after IFNalpha stimulation, incubation with IFNgamma induced STAT-1 phosphorylation only in SLE lymphocytes. Moreover, SLE monocytes showed a considerably higher increase in pSTAT-1 expression upon IFNgamma stimulation than monocytes from healthy individuals. Increased responsiveness of SLE monocytes to IFNgamma was also confirmed on the mRNA level, where expression of the IFN-inducible, STAT-1-dependent genes IP-10 and Mig was more efficiently increased in SLE cells. However, IFNgammaR was similarly expressed on SLE lymphocytes and monocytes and those from healthy individuals. In addition to supporting the role of IFNs in SLE immunopathogenesis in general, the findings of the present study support a role of IFNgamma in this disease.

An Aldehyde Oxidase in Developing Seeds of Arabidopsis Converts Benzaldehyde to Benzoic Acid

Arabidopsis (Arabidopsis thaliana) siliques synthesize high levels of benzoic acid (BA), which is incorporated into several glucosinolate compounds. The origin of BA in the siliques has not yet been determined. Here, we show that siliques have higher levels of benzaldehyde (BD)-oxidizing activity relative to leaves. The BD-oxidizing activity was purified from siliques in several chromatographic steps, and a 145-kD protein was identified as the enzyme most likely to possess this activity. The protein was trypsinized, and the sequence of the resulting peptides was determined by mass spectrometry, identifying it as the product of gene At1g04580, also designated as AAO4 (for ARABIDOPSIS ALDEHYDE OXIDASE4). AAO4 had previously been shown to be highly and specifically expressed in developing seeds, and its protein was shown to belong to a family of aldehyde oxidases. Here, we show that the AAO4 protein is an aldehyde oxidase that can use several substrates but that, among the substrates tested, has the lowest K(m) value (23 microm) with BD. AAO4 is able to oxidize BD without NAD(+), but its activity increases by 50% when this cofactor is added. The pH optimum of AAO4 is 7.0. Plants homozygous for a null allele in AAO4 showed a reduction of 30% to 45% in the total levels of BA in seeds as well as 7% to 9% and 32% to 38% decreases in the levels of 3-benzoyloxypropylglucosinolate and 4-benzoyloxybutylglucosinolate, respectively. Expressing AAO4 in Escherichia coli resulted in a 3-fold increase of BD-oxidizing activity in crude bacterial extracts over endogenous levels. These findings indicate that in Arabidopsis seeds, oxidation of BD contributes in part to the synthesis of BA.

Assessment of the transformation of equine skin–derived fibroblasts to multinucleated skeletal myotubes following lentiviral-induced expression of equine myogenic differentiation 1

To develop a reliable method for converting cultured equine skin-derived fibroblasts into muscle cells. Equine skin-derived fibroblasts. The equine myogenic differentiation 1 (eqMyoD) genomic sequence was obtained by use of equine bacterial artificial chromosome screening and PCR sequencing. Total mRNA was extracted from foal skeletal muscle, and eqMyoD cDNA was cloned into a plasmid vector with an internal ribosomal entry site to express bicistronic eqMyoD or enhanced green fluorescent protein (EGFP). Transient expression was confirmed by immunocytochemical analysis and western immunoblots in equine fibroblasts and fibroblasts from National Institutes of Health Swiss mouse embryos, prior to generation of a lentiviral vector containing the same coding sequences. Transformation of equine skin-derived cells into skeletal myotubes was examined by use of immunohistochemical analysis, western immunoblotting, and periodic acid-Schiff staining. eqMyoD mRNA consists of 960 bp and shares high homology with myogenic differentiation 1 from other mammals. Transfection confirmed the expression of a 53-kd protein with mainly nuclear localization. Lentiviral transduction was efficient, with approximately 80% of EGFP-positive cells transformed into multinucleated myotubes during 15 days, as determined by expression of the muscle-specific proteins desmin, troponin-T, and sarcomeric myosin and by cytoplasmic storage of glycogen. Equine primary fibroblasts were transformed by lentiviral transduction of eqMyoD into fusion-competent myoblasts. This may offer a preferable alternative to primary myoblast cultures for the investigation of cellular defects associated with muscle diseases of horses, such as recurrent exertional rhabdomyolysis and polysaccharide storage myopathy.

CD300f Triggering Modifies Myeloid Cell Function

CD300f, a member of the CD300 family of immunoregulatory molecules, is capable of signalling through association with both SHP-1 phosphatase and the p85α subunit of phosphoinositide 3-kinase. On normal cells, CD300f is expressed on monocytes and dendritic cells in the blood and bone marrow. CD300f is expressed on myeloid derived cell lines and Acute Myeloid Leukaemias (AMLs) and is an acknowledged candidate for antibody targeting of AML (Modra CJ et al. Blood 2006; 108:225B-225B and Zhao X et al Blood 2007; 110:531a–532a). We have generated a monoclonal antibody, MMRI- 23, specific for the extracellular domain of CD300f. MMRI-23 immunoprecipitates a 57kd protein from the myeloid derived cell lines HEL, THP-1 and U937 and this protein binds to a polyclonal antibody to CD300f (LMIR3) in Western blot analysis. Binding of MMRI-23 to myeloid cells was blocked by the CD300f recombinant proteins or the polyclonal CD300f antibody. The MMRI-23 mAb was used as a surrogate ligand to study the functional consequences of crosslinking CD300f on normal monocytes and myeloid derived cell lines. Purified peripheral blood monocytes were cultured for 18 hours in the presence of immobilised MMRI-23 or control mAb. MMRI-23 binding was not altered by activation of peripheral blood monocytes but crosslinking monocytes with MMRI- 23 induced downregulation of CD14 and CD33. There was significant inhibition of IL-6 but not IL-1β, IL-8 or TNFα secretion. Crosslinking monocytes or the U937 cell line with MMRI-23 increased specific chemotaxis towards CXCL12 (SDF-1). This increased migration index following MMRI-23 crosslinking was reversed in the presence of wortmannin indicating that MMRI-23 induces signalling through phosphoinositide 3-kinase. The effect of crosslinking did not enhance CXCR4 upregulation but did induce localization of CD300f and CXCR4 to the lipid rafts in myeloid cell line, U937. Thus CD300f plays a significant role in the regulation of monocyte migration to CXCR4. As CD300f is upregulated on around 70% of AMLs, this regulation of homing has major implications for the treatment of AML.

Expression, cellular localization and antibody responses of the African swine fever virus genes B602L and K205R

Previously, we identified serological immunodeterminants of African swine fever virus (ASFV), including pK205R and pB602L, without homologues in the database. pK205R is expressed as a 33-kD protein from 4 h post-infection onward, initially diffusely distributed throughout cells, and subsequently in viral factories. pK205R was not found in purified virus. Both pK205R and pB602L are recognised by hyperimmune antisera from domestic pigs and bushpigs at late time points after infection, suggesting they may be useful diagnostically to distinguish animals persistently infected with virus.

Cellular glutathione peroxidase in human brain: cellular distribution, and its potential role in the degradation of Lewy bodies in Parkinson’s disease and dementia with Lewy bodies

Glutathione peroxidase (GPx-1) is regarded as one of the mammalian cell's main antioxidant enzymes inactivating hydrogen peroxide and protecting against oxidative stress. Using control, Parkinson's disease (PD), and dementia with Lewy bodies tissue (DLB) we have shown that GPx-1 is a 21-kD protein under reducing conditions in all tissues examined but is not in high abundance in human brain. Using immunohistochemistry we have mapped the cellular distribution of GPx-1 and have shown it to be in highest levels in microglia and with lower levels in neurons. Only a trace amount was detectable in astrocytes using immunofluorescence and GPx-1 was not detectable in oligodendrocytes. GPx-1 positive microglia were hypertrophied and more abundant in PD and DLB tissues and were seen to be making multiple contacts with neurons. In some cases neurons containing Lewy bodies were surrounded by microglia. Unstructured Lewy bodies were enveloped with a layer of GPx-1 that was partially colocalized with alpha-synuclein whereas concentric Lewy bodies had discrete deposits of GPx-1 around the periphery which appeared to be involved in the degradation of the Lewy bodies. These results suggest that abnormal alpha-synuclein as found in Lewy bodies produce hydrogen peroxide and these neurons are capable of directing antioxidant enzymes to regions of oxidative stress. These results also suggest that GPx-1 positive microglia are involved in neuroprotection in PD and DLB and that GPx-1 is an important antioxidant enzyme in neuronal defences.