Simvastatin decreases the level of heparin-binding protein in patients with acute lung injury

Heparin-binding protein is released by neutrophils during inflammation and disrupts the integrity of the alveolar and capillary endothelial barrier implicated in the development of acute lung injury and systemic organ failure. We sought to investigate whether oral administration of simvastatin to patients with acute lung injury reduces plasma heparin-binding protein levels and improves intensive care unit outcome.

Unspliced X-box-binding Protein 1 (XBP1) Protects Endothelial Cells from Oxidative Stress through Interaction with Histone Deacetylase 3

It is well-known that atherosclerosis occurs geographically at branch points where disturbed flow predisposes to the development of plaque via triggering of oxidative stress and inflammatory reactions. In this study, we found that disturbed flow activated anti-oxidative reactions via up-regulating heme oxygenase 1 (HO-1) in an X-box binding protein 1 (XBP1) and histone deacetylase 3 (HDAC3)-dependent manner. Disturbed flow concomitantly up-regulated the unspliced XBP1 (XBP1u) and HDAC3 in a vascular endothelial growth factor receptor (VEGFR) and PI3K/Akt dependent manner. The presence of XBP1 was essential for the up-regulation of HDAC3 protein. Over-expression of XBP1u and/or HDAC3 activated Akt1 phosphorylation, Nrf2 protein stabilization and nuclear translocation, and HO-1 expression. Knockdown of XBP1u decreased the basal level and disturbed flow-induced Akt1 phosphorylation, Nrf2 stabilization and HO-1 expression. Knockdown of HDAC3 ablated XBP1u-mediated effects. The mammalian target of rapamycin complex 2 (mTORC2) inhibitor, AZD2014, ablated XBP1u or HDAC3 or disturbed flow-mediated Akt1 phosphorylation, Nrf2 nuclear translocation and HO-1 expression. Neither actinomycin D nor cycloheximide affected disturbed flow-induced up-regulation of Nrf2 Protein. Knockdown of Nrf2 abolished XBP1u or HDAC3 or disturbed flow-induced HO-1 up-regulation. Co-immunoprecipitation assays demonstrated that XBP1u physically bound to HDAC3 and Akt1. The region of amino acids 201 to 323 of the HDAC3 protein was responsible for the binding to XBP1u. Double immunofluorescence staining revealed that the interactions between Akt1 and mTORC2, Akt1 and HDAC3, Akt1 and XBP1u, HDAC3 and XBP1u occurred in the cytosol. Thus, we demonstrate that XBP1u and HDAC3 exert a protective effect on disturbed flow-induced oxidative stress via up-regulation of mTORC2-dependent Akt1 phosphorylation and Nrf2-mediated HO-1 expression.

CCAAT/enhancer binding protein α predicts poorer prognosis and prevents energy starvation-induced cell death in hepatocellular carcinoma

CCAAT enhancer binding protein α (C/EBPα) plays an essential role in cellular differentiation, growth, and energy metabolism. Here, we investigate the correlation between C/EBPα and hepatocellular carcinoma (HCC) patient outcomes and how C/EBPα protects cells against energy starvation. Expression of C/EBPα protein was increased in the majority of HCCs examined (191 pairs) compared with adjacent nontumor liver tissues in HCC tissue microarrays. Its upregulation was correlated significantly with poorer overall patient survival in both Kaplan-Meier survival (P = 0.017) and multivariate Cox regression (P = 0.028) analyses. Stable C/EBPα-silenced cells failed to establish xenograft tumors in nude mice due to extensive necrosis, consistent with increased necrosis in human C/EBPα-deficient HCC nodules. Expression of C/EBPα protected HCC cells in vitro from glucose and glutamine starvation-induced cell death through autophagy-involved lipid catabolism. Firstly, C/EBPα promoted lipid catabolism during starvation, while inhibition of fatty acid beta-oxidation significantly sensitized cell death. Secondly, autophagy was activated in C/EBPα-expressing cells, and the inhibition of autophagy by ATG7 knockdown or chloroquine treatment attenuated lipid catabolism and subsequently sensitized cell death. Finally, we identified TMEM166 as a key player in C/EBPα-mediated autophagy induction and protection against starvation.

CONCLUSION: The C/EBPα gene is important in that it links HCC carcinogenesis to autophagy-mediated lipid metabolism and resistance to energy starvation; its expression in HCC predicts poorer patient prognosis.

Susceptibility to Invasive Meningococcal Disease: Polymorphism of Complement System Genes and Neisseria meningitidis Factor H Binding Protein

BACKGROUND: Neisseria meningitidis can cause severe infection in humans. Polymorphism of Complement Factor H (CFH) is associated with altered risk of invasive meningococcal disease (IMD). We aimed to find whether polymorphism of other complement genes altered risk and whether variation of N. meningitidis factor H binding protein (fHBP) affected the risk association.

METHODS: We undertook a case-control study with 309 European cases and 5,200 1958 Birth Cohort and National Blood Service cohort controls. We used additive model logistic regression, accepting P<0.05 as significant after correction for multiple testing. The effects of fHBP subfamily on the age at infection and severity of disease was tested using the independent samples median test and Student's T test. The effect of CFH polymorphism on the N. meningitidis fHBP subfamily was investigated by logistic regression and Chi squared test.

RESULTS: Rs12085435 A in C8B was associated with odds ratio (OR) of IMD (0.35 [95% CI 0.19-0.67]; P = 0.03 after correction). A CFH haplotype tagged by rs3753396 G was associated with IMD (OR 0.56 [95% CI 0.42-0.76], P = 1.6x10-4). There was no bacterial load (CtrA cycle threshold) difference associated with carriage of this haplotype. Host CFH haplotype and meningococcal fHBP subfamily were not associated. Individuals infected with meningococci expressing subfamily A fHBP were younger than those with subfamily B fHBP meningococci (median 1 vs 2 years; P = 0.025).

DISCUSSION: The protective CFH haplotype alters odds of IMD without affecting bacterial load for affected heterozygotes. CFH haplotype did not affect the likelihood of infecting meningococci having either fHBP subfamily. The association between C8B rs12085435 and IMD requires independent replication. The CFH association is of interest because it is independent of known functional polymorphisms in CFH. As fHBP-containing vaccines are now in use, relationships between CFH polymorphism and vaccine effectiveness and side-effects may become important.

HPV16 Down-Regulates the Insulin-Like Growth Factor Binding Protein 2 to Promote Epithelial Invasion in Organotypic Cultures

Cervical cancer is a multi-stage disease caused by human papillomaviruses (HPV) infection of cervical epithelial cells, but the mechanisms regulating disease progression are not clearly defined. Using 3-dimensional organotypic cultures, we demonstrate that HPV16 E6 and E7 proteins alter the secretome of primary human keratinocytes resulting in local epithelial invasion. Mechanistically, absence of the IGF-binding protein 2 (IGFBP2) caused increases in IGFI/II signalling and through crosstalk with KGF/FGFR2b/AKT, cell invasion. Repression of IGFBP2 is mediated by histone deacetylation at the IGFBP2 promoter and was reversed by treatment with histone deacetylase (HDAC) inhibitors. Our in vitro findings were confirmed in 50 invasive cancers and 79 cervical intra-epithelial neoplastic lesions caused by HPV16 infection, where IGFBP2 levels were reduced with increasing disease severity. In summary, the loss of IGFBP2 is associated with progression of premalignant disease, and sensitises cells to pro-invasive IGF signalling, and together with stromal derived factors promotes epithelial invasion.

IGF-Binding Protein 2 - Oncogene or Tumor Suppressor?

The role of insulin-like growth factor binding protein 2 (IGFBP2) in cancer is unclear. In general, IGFBP2 is considered to be oncogenic and its expression is often observed to be elevated in cancer. However, there are a number of conflicting reports in vitro and in vivo where IGFBP2 acts in a tumor suppressor manner. In this mini-review, we discuss the factors influencing the variation in IGFBP2 expression in cancer and our interpretation of these findings.

Glycosylation of Vitamin D Binding Protein Reduced in Juvenile Idiopathic Arthritis Patients At Risk of Disease Extension.

Background/Purpose:Juvenile idiopathic arthritis (JIA) comprises a poorly understood group of chronic, childhood onset, autoimmune diseases with variable clinical outcomes. We investigated whether profiling of the synovial fluid (SF) proteome by a fluorescent dye based, two-dimensional gel (DIGE) approach could distinguish the subset of patients in whom inflammation extends to affect a large number of joints, early in the disease process. The post-translational modifications to candidate protein markers were verified by a novel deglycosylation strategy.Methods:SF samples from 57 patients were obtained around time of initial diagnosis of JIA. At 1 year from inclusion patients were categorized according to ILAR criteria as oligoarticular arthritis (n=26), extended oligoarticular (n=8) and polyarticular disease (n=18). SF samples were labeled with Cy dyes and separated by two-dimensional electrophoresis. Multivariate analyses were used to isolate a panel of proteins which distinguish patient subgroups. Proteins were identified using MALDI-TOF mass spectrometry with vitamin D binding protein (VDBP) expression and siaylation further verified by immunohistochemistry, ELISA test and immunoprecipitation. Candidate biomarkers were compared to conventional inflammation measure C-reactive protein (CRP). Sialic acid residues were enzymatically cleaved from immunopurified SF VDBP, enriched by hydrophilic interaction liquid chromatography (HILIC) and analysed by mass spectrometry.Results:Hierarchical clustering based on the expression levels of a set of 23 proteins segregated the extended-to-be oligoarticular from the oligoarticular patients. A cleaved isoform of VDBP, spot 873, is present at significantly reduced levels in the SF of oligoarticular patients at risk of disease extension, relative to other subgroups (p<0.05). Conversely total levels of vitamin D binding protein are elevated in plasma and ROC curves indicate an improved diagnostic sensitivity to detect patients at risk of disease extension, over both spot 873 and CRP levels. Sialysed forms of intact immunopurified VDBP were more prevalent in persistent oligoarticular patient synovial fluids.Conclusion:The data indicate that a subset of the synovial fluid proteome may be used to stratify patients to determine risk of disease extension. Reduced conversion of VDBP to a macrophage activation factor may represent a novel pathway contributing to increased risk of disease extension in JIA patients.

von Hippel Lindau binding protein 1-mediated degradation of integrase affects HIV-1 gene expression at a postintegration step

HIV-1 integrase, the viral enzyme responsible for provirus integration into the host genome, can be actively degraded by the ubiquitin-proteasome pathway. Here, we identify von Hippel-Lindau binding protein 1(VBP1), a subunit of the prefoldin chaperone, as an integrase cellular binding protein that bridges interaction between integrase and the cullin2 (Cul2)-based von Hippel-Lindau (VHL) ubiquitin ligase. We demonstrate that VBP1 and Cul2/VHL are required for proper HIV-1 expression at a step between integrase-dependent proviral integration into the host genome and transcription of viral genes. Using both an siRNA approach and Cul2/VHL mutant cells, we show that VBP1 and the Cul2/VHL ligase cooperate in the efficient polyubiquitylation of integrase and its subsequent proteasome-mediated degradation. Results presented here support a role for integrase degradation by the prefoldin-VHL-proteasome pathway in the integration-transcription transition of the viral replication cycle.

Serum Fatty Acid Binding Protein 4 (FABP4) Predicts Pre-eclampsia in Women with Type 1 Diabetes

Objective: To examine the association between fatty acid binding protein 4 (FABP4) and pre-eclampsia risk in women with type 1 diabetes.
Reesearch Design and Methods: Serum FABP4 was measured in 710 women from the Diabetes and Pre-eclampsia Intervention Trial (DAPIT) in early pregnancy and in the second trimester (median 14 and 26 weeks gestation, respectively).
Results: FABP4 was significantly elevated in early pregnancy (geometric mean 15.8 ng/mL [interquartile range 11.6–21.4] vs. 12.7 ng/mL [interquartile range 9.6–17]; P < 0.001) and the second trimester (18.8 ng/mL [interquartile range 13.6–25.8] vs. 14.6 ng/mL [interquartile range 10.8–19.7]; P < 0.001) in women in whom pre-eclampsia later developed. Elevated second-trimester FABP4 level was independently associated with pre-eclampsia (odds ratio 2.87 [95% CI 1.24, 6.68], P = 0.03). The addition of FABP4 to established risk factors significantly improved net reclassification improvement at both time points and integrated discrimination improvement in the second trimester.
Conclusions: Increased second-trimester FABP4 independently predicted pre-eclampsia and significantly improved reclassification and discrimination. FABP4 shows potential as a novel biomarker for pre-eclampsia prediction in women with type 1 diabetes.

Cybr, a cytokine-inducible protein that binds cytohesin-1 and regulates its activity

Cytokines regulate lymphocyte development and differentiation, but precisely how they control these processes is still poorly understood. By using microarray technology to detect cytokine-induced genes, we identified a cDNA encoding Cybr, which was increased markedly in cells incubated with IL-2 and IL-12. The mRNA was most abundant in hematopoietic cells and tissues. The predicted amino acid sequence is similar to that of GRP-1-associated protein (GRASP), a recently identified retinoic acid-induced cytohesin-binding protein. Physical interaction, dependent on the coiled-coil domains of Cybr and cytohesin-1, was demonstrated by coimmunoprecipitation of the overexpressed proteins from 293T cells. Cytohesin-1, in addition to its role in cell adhesion, is a guanine nucleotide-exchange protein activator of ARF GTPases. Acceleration of guanosine 5'-O-(thiotriphosphate) binding to ARF by cytohesin-1 in vitro was enhanced by Cybr. Because the binding protein modified activation of ADP ribosylation factor by cytohesin-1, we designate this cytokine-inducible protein Cybr (cytohesin binder and regulator).

Cytoplasmic Irradiation Induces Mitochondrial-Dependent 53BP1 Protein Relocalization in Irradiated and Bystander Cells

The accepted paradigm for radiation effects is that direct DNA damage via energy deposition is required to trigger the downstream biological consequences. The radiation-induced bystander effect is the ability of directly irradiated cells to interact with their nonirradiated neighbors, which can then show responses similar to those of the targeted cells. p53 binding protein 1 (53BP1) forms foci at DNA double-strand break sites and is an important sensor of DNA damage. This study used an ionizing radiation microbeam approach that allowed us to irradiate specifically the nucleus or cytoplasm of a cell and quantify response in irradiated and bystander cells by studying ionizing radiation-induced foci (IRIF) formation of 53BP1 protein. Our results show that targeting only the cytoplasm of a cell is capable of eliciting 53BP1 foci in both hit and bystander cells, independently of the dose or the number of cells targeted. Therefore, direct DNA damage is not required to trigger 53BP1 IRIF. The use of common reactive oxygen species and reactive nitrogen species (RNS) inhibitors prevent the formation of 53BP1 foci in hit and bystander cells. Treatment with filipin to disrupt membrane-dependent signaling does not prevent the cytoplasmic irradiation-induced 53BP1 foci in the irradiated cells, but it does prevent signaling to bystander cells. Active mitochondrial function is required for these responses because pseudo-rho(0) cells, which lack mitochondrial DNA, could not produce a bystander signal, although they could respond to a signal from normal rho(+) cells.

IQ motif selectivity in human IQGAP1: binding of myosin essential light chain and S100B.

IQGAPs are cytoskeletal scaffolding proteins which link signalling pathways to the reorganisation of actin and microtubules. Human IQGAP1 has four IQ motifs each of which binds to calmodulin. The same region has been implicated in binding to two calmodulin-like proteins, the myosin essential light chain Mlc1sa and the calcium and zinc ion binding protein S100B. Using synthetic peptides corresponding to the four IQ motifs of human IQGAP1, we showed by native gel electrophoresis that only the first IQ motif interacts with Mlc1sa. This IQ motif, and also the fourth, interacts with the budding yeast myosin essential light chain Mlc1p. The first and second IQ motifs interact with S100B in the presence of calcium ions. This clearly establishes that S100B can interact with its targets through IQ motifs in addition to interacting via previously reported sequences. These results are discussed in terms of the function of IQGAP1 and IQ motif recognition.

Protein expression profiling during chick retinal maturation: a proteomics-based approach

Background: The underlying pathways that drive retinal neurogenesis and synaptogenesis are still relatively poorly understood. Protein expression analysis can provide direct insight into these complex developmental processes. The aim of this study was therefore to employ proteomic analysis to study the developing chick retina throughout embryonic (E) development commencing at day 12 through 13, 17, 19 and post-hatch (P) 1 and 33 days.

Results: 2D proteomic and mass spectrometric analysis detected an average of 1514 spots per gel with 15 spots demonstrating either modulation or constitutive expression identified via MS. Proteins identified included alpha and beta-tubulin, alpha enolase, B-creatine kinase, gamma-actin, platelet-activating factor (PAF), PREDICTED: similar to TGF-beta interacting protein 1, capping protein (actin filament muscle Z line), nucleophosmin 1 (NPM1), dimethylarginine dimethylaminohydrolase, triosphoaphate isomerase, DJ1, stathmin, fatty acid binding protein 7 (FABP7/B-FABP), beta-synuclein and enhancer of rudimentary homologue.

Conclusion: This study builds upon previous proteomic investigations of retinal development and represents the addition of a unique data set to those previously reported. Based on reported bioactivity some of the identified proteins are most likely to be important to normal retinal development in the chick. Continued analysis of the dynamic protein populations present at the early stages and throughout retinal development will increase our understanding of the molecular events underpinning retinogenesis.

Xenopus cytoplasmic linker-associated protein 1 (XCLASP1) promotes axon elongation and advance of pioneer microtubules

Dynamic microtubules (MTs) are required for neuronal guidance, in which axons extend directionally toward their target tissues. We found that depletion of the MT-binding protein Xenopus cytoplasmic linker-associated protein 1 (XCLASP1) or treatment with the MT drug Taxol reduced axon outgrowth in spinal cord neurons. To quantify the dynamic distribution of MTs in axons, we developed an automated algorithm to detect and track MT plus ends that have been fluorescently labeled by end-binding protein 3 (EB3). XCLASP1 depletion reduced MT advance rates in neuronal growth cones, very much like treatment with Taxol, demonstrating a potential link between MT dynamics in the growth cone and axon extension. Automatic tracking of EB3 comets in different compartments revealed that MTs increasingly slowed as they passed from the axon shaft into the growth cone and filopodia. We used speckle microscopy to demonstrate that MTs experience retrograde flow at the leading edge. Microtubule advance in growth cone and filopodia was strongly reduced in XCLASP1-depleted axons as compared with control axons, but actin retrograde flow remained unchanged. Instead, we found that XCLASP1-depleted growth cones lacked lamellipodial actin organization characteristic of protrusion. Lamellipodial architecture depended on XCLASP1 and its capacity to associate with MTs, highlighting the importance of XCLASP1 in actin-microtubule interactions.