EVI1 controls proliferation in acute myeloid leukaemia through modulation of miR-1-2

Bakground:

The EVI1(ecotropic virus integration site 1) gene codes for a zinc-finger transcription factor, whose transcriptional activation leads to a particularly aggressive form of acute myeloid leukaemia (AML). Although, EVI1 interactions with key proteins in hematopoiesis have been previously described, the precise role of this transcription factor in promoting leukaemic transformation is not completely understood. Recent works have identified specific microRNA (miRNA) signatures in different AML subgroups. However, there is no analysis of miRNAs profiles associated with EVI1 overexpression in humans.

Methods:

We performed QT-RT–PCR to assess the expression of 250 miRNAs in cell lines with or without EVI1 overexpression and in patient samples. We used ChIP assays to evaluated the possible binding of EVI1 binding to the putative miRNA promoter. Proliferation of the different cell lines transfected with the anti- or pre-miRs was quantified by MTT.

Results:

Our data showed that EVI1 expression was significantly correlated with the expression of miR-1-2 and miR-133-a-1 in established cell lines and in patient samples. ChIP assays confirmed that EVI1 binds directly to the promoter of these two miRNAs. However, only miR-1-2 was involved in abnormal proliferation in EVI1 expressing cell lines.

Conclusions:

Our data showed that EVI1 controls proliferation in AML through modulation of miR-1-2. This study contributes to further understand the transcriptional networks involving transcription factors and miRNAs in AML.

Validation of the Spanish, Portuguese and French versions of the Lupus Damage Index questionnaire: data from North and South America, Spain and Portugal

We have previously developed and validated a self-administered questionnaire, modelled after the Systemic Lupus International Collaborating Clinics Damage Index (SDI), the Lupus Damage Index Questionnaire (LDIQ), which may allow the ascertainment of this construct in systemic lupus erythematosus (SLE) patients followed in the community and thus expand observations made about damage. We have now translated, back-translated and adapted the LDIQ to Spanish, Portuguese and French and applied it to patients followed at academic and non-academic centres in North and South America, Portugal and Spain while their physicians scored the SDI. A total of 887 patients (659 Spanish-speaking, 140 Portuguese-speaking and 80 French-speaking patients) and 40 physicians participated. Overall, patients scored all LDIQ versions higher than their physicians (total score and all domains). Infrequent manifestations had less optimal clinimetric properties but overall agreement was more than 95% for the majority of items. Higher correlations were observed among the Spanish-speaking patients than the Portuguese-speaking and French-speaking patients; further adjustments may be needed before the Portuguese and French versions of the LDIQ are applied in community-based studies. The relationship between the LDIQ and other outcome parameters is currently being investigated in a different patient sample.

Metabolic syndrome in Argentinean patients with systemic lupus erythematosus

The objective was to determine the prevalence of the metabolic syndrome (MS) in patients with systemic lupus erythematosus (SLE) in Argentina, to assess the factors associated to it, and to compare the results with a control group with non-inflammatory disorders. The study included 147 patients with SLE and 119 controls. MS was defined according to criteria by the American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI) Scientific Statement. Demographic characteristics, Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) and Systemic Lupus International Collaborating Clinics/ACR Damage Index (SDI) were assessed as well as administration, maximum dose and cumulative dose of prednisone and hydroxychloroquine (HCQ). MS prevalence was 28.6% (CI 95%: 21.4-36.6) in patients with SLE and 16% in controls (P = 0.0019). Patients with SLE presented higher arterial hypertension frequency compared with controls (43 vs 25%, P = 0.007). When comparing lupus patients with MS (n = 41) and without MS (n = 106), no significant differences were observed regarding duration of the disease, SLEDAI or cumulative prednisone dose. Cumulative damage was associated independently with MS (OR 1.98; P = 0.021), whereas HCQ use was found to be protective (OR 0.13; P = 0.015). Patients with lupus presented higher MS prevalence than controls with non-inflammatory disorders, and occurrence of arterial hypertension was also higher. MS was associated with cumulative damage; the use of HCQ showed to be protective against presence of MS.

X-ray magnetic circular dichroism and small angle neutron scattering studies of thiol capped gold nanoparticles

X-ray magnetic circular dichroism (XMCD) and Small Angle Neutron Scattering (SANS) measurements were performed on thiol capped Au nanoparticles (NPs) embedded into polyethylene. An XMCD signal of 0.8 x 10(-4) was found at the Au L3 edge of thiol capped Au NPs embedded in a polyethylene matrix for which Superconducting Quantum Interference Device (SQUID) magnetometry yielded a saturation magnetization, M(S), of 0.06 emu/g(Au). SANS measurements showed that the 3.2 nm average-diameter nanoparticles are 28% polydispersed, but no detectable SANS magnetic signal was found with the resolution and sensitivity accessible with the neutron experiment. A comparison with previous experiments carried out on Au NPs and multilayers, yield to different values between XMCD signals and magnetization measured by SQUID magnetometer. We discuss the origin of those differences.

Mercury in edible mushrooms and underlying soil: bioconcentration factors and toxicological risk

Wild growing mushrooms are a popular delicacy in many countries, but some species accumulate high levels of toxic heavy metals, e.g., mercury, both in unpolluted and mildly polluted areas. In this study, we examined the accumulation capacity of mercury in edible mushrooms in relation to certain factors and their possible toxicological implications. Total concentrations of mercury were determined by an anodic stripping voltammetric technique using a gold disc as the working electrode in 238 samples of the fruiting bodies of 28 wild growing edible mushrooms species and the underlying soil. The mushrooms were collected from different sites in the province of Lugo (NW Spain). The hymenophore (H) and the rest of the fruiting body (RFB) were analysed separately. The highest mean mercury concentrations (mg/kg dry weight) were found in Boletus pinophilus (6.9 in H and 4.5 in RFB), Agaricus macrosporus (5.1 in H and 3.7 in RFB), Lepista nuda (5.1 in H and 3.1 in RFB) and Boletus aereus (4.6 in H and 3.3 in RFB), while the lowest was found in Agrocybe cylindrica (0.34 in H and 0.26 in RFB) and Fistulina hepatica (0.30 in H and 0.22 in RFB). All mushroom species accumulated mercury (BCF>1) in relation to the underlying soils. There were no statistically significant differences between the mercury levels in the hymenophore and in the rest of the fruiting body. The total mercury concentrations were compared to data in the literature and to levels set by legislation. It was concluded that consumption of the majority of the studied mushrooms is not a toxicological risk as far as mercury content is concerned, although the species B.pinophilus, A.macrosporus, L.nuda and B.aereus should be consumed in low amounts.

Polarized MT1-MMP-CD44 interaction and CD44 cleavage during cell retraction reveal an essential role for MT1-MMP in CD44-mediated invasion

The adhesion molecule CD44 and the membrane-type matrix metalloproteinase MT1-MMP act coordinately in tumor cells to promote cell invasion through a yet unclear mechanism. We are interested in studying the interplay between CD44 and MT1-MMP in carcinoma cells embedded in HA containing three-dimensional collagen I matrices (3D HA-Col I) by time-lapse confocal microscopy imaging. Here we report the in vivo interaction between CD44 and MT1-MMP, revealed by fluorescence resonance energy transfer (FRET) microscopy. MT1-MMP interacts with CD44 preferentially at the trailing edge of the invading tumor cells during rear retraction and on membrane fragments released during the invasion process. A fluorescent biosensor designed to monitor the proteolytic processing of CD44 by live cell imaging demonstrates that cleavage of the CD44 extracellular domain is enriched in the retracting rear ends of invasive tumor cells. Invasion assays showed that MT1-MMP mediates CD44-dependent tumor-cell invasion, whereas CD44 is not essential for MT1-MMP-mediated invasion of 3D HA-Col I matrices. Together, our results support a role for MT1-MMP in cell retraction during CD44-mediated cell invasion.

Surface plasmon resonance and magnetism of thiol-capped gold nanoparticles

Surface plasmon resonance measurements and magnetic characterization studies have been carried out for two types of thiol-capped gold nanoparticles (NPs) with similar diameters between 2.0 and 2.5 nm and different organic molecules linked to the sulfur atom: dodecanethiol and tiopronin. In addition, Au NPs capped with tetraoctyl ammonium bromide have also been included in the investigation since such capping molecules weakly interact with the gold surface atoms and, therefore, this system can be used as a model for naked gold NPs; such particles presented a bimodal size distribution with diameters around 1.5 and 5 nm. The plasmon resonance is non-existent for tiopronin-capped NPs, whereas a trace of such a feature is observed for NPs covered with dodecanethiol molecules and a bulk-like feature is measured for NPs capped with tetralkyl ammonium salts. These differences would indicate that the modification of the surface electronic structure of the Au NPs depends on the geometry and self-assembling capabilities of the capping molecules and on the electric charge transferred between Au and S atoms. Regarding the magnetization, dodecanethiol-capped NPs have a ferromagnetic-like behaviour, while the NPs capped with tiopronin exhibit a paramagnetic behaviour and tetralkyl ammonium-protected NPs are diamagnetic across the studied temperature range; straight chains with a well-defined symmetry axis can induce orbital momentum on surface electrons close to the binding atoms. The orbital momentum not only contributes to the magnetization but also to the local anisotropy, giving rise to permanent magnetism. Due to the domain structure of the adsorbed molecules, orbital momentum is not induced for tiopronin-capped NPs and the charge transfer only induces a paramagnetic spin component.

Removal of toxic metals from aqueous solutions by fungal biomass of Agaricus macrosporus

Fungi such as Agaricus macrosporus show potential for the removal of heavy metals from aqueous solutions contaminated by zinc, copper, mercury, cadmium or lead. This study investigated biosorption of these metals by living or non-living biomass of A. macrosporus from an acid solution, an acid solution supplemented with potassium and phosphorus, and an alkaline solution. Uptake showed a pH-dependent profile. Maximum percentage uptake of all metals was found to occur at alkaline pH (Cu 96%, Pb 89%). With living biomass, metal biosorption was greater and faster in K/P-supplemented acid medium than in non-supplemented acid medium, with equilibrium reached within 15 min for all metals, and the highest percentage uptake being of cadmium (96%). In general, the greatest differences in biosorption capacity were seen for living biomass, between supplemented and non-supplemented acid medium; the smallest differences were between living and dead biomass in alkaline medium. These results support the potential utility of A. macrosporus for heavy metal removal.

PET/CT image registration: Preliminary tests for its application to clinical dosimetry in radiotherapy

The quality of dosimetry in radiotherapy treatment requires the accurate delimitation of the gross tumor volume. This can be achieved by complementing the anatomical detail provided by CT images through fusion with other imaging modalities that provide additional metabolic and physiological information. Therefore, use of multiple imaging modalities for radiotherapy treatment planning requires an accurate image registration method. This work describes tests carried out on a Discovery LS positron emission/computed tomography (PET/CT) system by General Electric Medical Systems (GEMS), for its later use to obtain images to delimit the target in radiotherapy treatment. Several phantoms have been used to verify image correlation, in combination with fiducial markers, which were used as a system of external landmarks. We analyzed the geometrical accuracy of two different fusion methods with the images obtained with these phantoms. We first studied the fusion method used by the PET/CT system by GEMS (hardware fusion) on the basis that there is satisfactory coincidence between the reconstruction centers in CT and PET systems; and secondly the fiducial fusion, a registration method, by means of least-squares fitting algorithm of a landmark points system. The study concluded with the verification of the centroid position of some phantom components in both imaging modalities. Centroids were estimated through a calculation similar to center-of-mass, weighted by the value of the CT number and the uptake intensity in PET. The mean deviations found for the hardware fusion method were: deltax/ +/-sigma = 3.3 mm +/- 1.0 mm and /deltax/ +/-sigma = 3.6 mm +/- 1.0 mm. These values were substantially improved upon applying fiducial fusion based on external landmark points: /deltax/ +/-sigma = 0.7 mm +/- 0.8 mm and /deltax/ +/-sigma = 0.3 mm 1.7 mm. We also noted that differences found for each of the fusion methods were similar for both the axial and helical CT image acquisition protocols.

MT1-MMP proinvasive activity is regulated by a novel Rab8-dependent exocytic pathway

MT1-matrix metalloproteinase (MT1-MMP) is one of the most critical factors in the invasion machinery of tumor cells. Subcellular localization to invasive structures is key for MT1-MMP proinvasive activity. However, the mechanism driving this polarized distribution remains obscure. We now report that polarized exocytosis of MT1-MMP occurs during MDA-MB-231 adenocarcinoma cell migration into collagen type I three-dimensional matrices. Polarized trafficking of MT1-MMP is triggered by beta1 integrin-mediated adhesion to collagen, and is required for protease localization at invasive structures. Localization of MT1-MMP within VSV-G/Rab8-positive vesicles, but not in Rab11/Tf/TfRc-positive compartment in invasive cells, suggests the involvement of the exocytic traffic pathway. Furthermore, constitutively active Rab8 mutants induce MT1-MMP exocytic traffic, collagen degradation and invasion, whereas Rab8- but not Rab11-knockdown inhibited these processes. Altogether, these data reveal a novel pathway of MT1-MMP redistribution to invasive structures, exocytic vesicle trafficking, which is crucial for its role in tumor cell invasiveness. Mechanistically, MT1-MMP delivery to invasive structures, and therefore its proinvasive activity, is regulated by Rab8 GTPase.

Outbreak of trichinellosis in Spain and Sweden due to consumption of wild boar meat contaminated with Trichinella britovi

Early this year, 21 people became ill with trichinellosis in both Spain and Sweden. This was traced to consumption of home-made wild boar sausage from an original source in Spain.

The dsRNA protein kinase PKR: virus and cell control

The IFN-induced double-stranded RNA-dependent protein kinase (PKR) is one of the four mammalian serine-threonine kinases (the three others being HRI, GCN2 and PERK) that phosphorylate the eIF2 alpha translation initiation factor, in response to stress signals, mainly as a result of viral infections. eIF2 alpha phosphorylation results in arrest of translation of both cellular and viral mRNAs, an efficient way to inhibit virus replication. The particularity of PKR is to activate by binding to dsRNA through two N terminal dsRNA binding motifs (dsRBM). PKR activation during a viral infection represents a threat for several viruses, which have therefore evolved to express PKR inhibitors, such as the Vaccinia E3L and K3L proteins. The function of PKR can also be regulated by cellular proteins, either positively (RAX/PACT; Mda7) or negatively (p58IPK, TRBP, nucleophosmin, Hsp90/70). PKR can provoke apoptosis, in part through its ability to control protein translation, but the situation appears to be more complex, as NF-kappaB, ATF-3 and p53 have also been implicated. PKR-induced apoptosis involves mainly the FADD/caspase 8 pathway, while the mitochondrial APAF/caspase 9 pathway is also engaged. As a consequence of the effects of PKR on translation, transcription and apoptosis, PKR can function to control cell growth and cell differentiation, and its activity can be controlled by the action of several oncogenes.

Impact of protein kinase PKR in cell biology: from antiviral to antiproliferative action

The double-stranded RNA-dependent protein kinase PKR is a critical mediator of the antiproliferative and antiviral effects exerted by interferons. Not only is PKR an effector molecule on the cellular response to double-stranded RNA, but it also integrates signals in response to Toll-like receptor activation, growth factors, and diverse cellular stresses. In this review, we provide a detailed picture on how signaling downstream of PKR unfolds and what are the ultimate consequences for the cell fate. PKR activation affects both transcription and translation. PKR phosphorylation of the alpha subunit of eukaryotic initiation factor 2 results in a blockade on translation initiation. However, PKR cannot avoid the translation of some cellular and viral mRNAs bearing special features in their 5' untranslated regions. In addition, PKR affects diverse transcriptional factors such as interferon regulatory factor 1, STATs, p53, activating transcription factor 3, and NF-kappaB. In particular, how PKR triggers a cascade of events involving IKK phosphorylation of IkappaB and NF-kappaB nuclear translocation has been intensively studied. At the cellular and organism levels PKR exerts antiproliferative effects, and it is a key antiviral agent. A point of convergence in both effects is that PKR activation results in apoptosis induction. The extent and strength of the antiviral action of PKR are clearly understood by the findings that unrelated viral proteins of animal viruses have evolved to inhibit PKR action by using diverse strategies. The case for the pathological consequences of the antiproliferative action of PKR is less understood, but therapeutic strategies aimed at targeting PKR are beginning to offer promising results.

Ground laser remote sensing measurements of a Saharan dust outbreak in Central Spain. Influence on PM10 concentrations in the lower and upper Spanish plateaus

This paper presents the hourly evolution of a severe Saharan dust outbreak, (SDO), affecting Central Spain over July 23-24, 2004 measured with a laser remote sensing device at a location close to the Guadarrama mountain range foothills and its impact on PM10 levels (particles with an aerodynamic diameter below 10 microm) recorded at four contrasting monitoring stations located in the upper and lower Spanish plateau, some 170km apart. During the period of study the Saharan dust layer, (SDL), presented significant hourly variability in height (3600-1500m), depth (1500-700m) and aerosol dust loading (extinction coefficient, EC, 0.22-1.28km(-1)). Overnight layering was generally observed whereas a well mixed layer prevailed in the afternoon. The (SDO) impact on the lower levels took place approximately 12h after the (SDL) was initially observed and triggered by a descending dust enriched, evidencing the important role of subsidence over the presence of dust in lower altitudes. During the event, PM10 levels at all the stations exceeded EU air quality daily mean standards, 50 microgm(-3), on 2-4days. The maximum values ranged from 185 to 245 microgm(-3) depending on the monitoring station. The impact on PM10 spread from 2days in the upper plateau to 3-4 in the lower plateau, in agreement with the geographical location of the monitoring stations with respect to the southwest origin of the intrusion. The impact was even more dramatic on PM10 hourly concentrations, leading to maximum hourly peaks ranging from 322 to 598 microgm(-3) again depending on the monitoring station. Correlations between EC vertical profiles and PM10 hourly concentrations at the monitoring stations showed the great influence of the (SDO) on surface concentrations. The best linear fits corresponded to the extinction coefficients in the lower altitudes (close to the lower range of the device 500-650m), EC2, yielding satisfactory correlation coefficients ranging from 0.68 to 0.71. The low variability of the slope of each individual linear fit, 19.2%, shows the similar impact of (SDO) on the PM10 hourly concentrations recorded in the area under study.

No evidence of association between genetic variants of the PDCD1 ligands and SLE

PDCD1, an immunoreceptor involved in peripheral tolerance has previously been shown to be genetically associated with systemic lupus erythematosus (SLE). PDCD1 has two ligands whose genes are located in close proximity on chromosome 9p24. Our attention was drawn to these ligands after finding suggestive linkage to a marker (gata62f03, Z=2.27) located close to their genes in a genome scan of Icelandic families multiplex for SLE. Here, we analyse Swedish trios (N=149) for 23 single nucleotide polymorphisms (SNPs) within the genes of the PDCD1 ligands. Initially, indication of association to eight SNPs was observed, and these SNPs were therefore also analysed in Mexican trios (N=90), as well as independent sets of patients and controls from Sweden (152 patients, 448 controls) and Argentina (288 patients, 288 controls). We do not find support for genetic association to SLE. This is the first genetic study of SLE and the PDCD1 ligands and the lack of association in several cohorts implies that these genes are not major risk factors for SLE.

Fe impurities weaken the ferromagnetic behavior in Au nanoparticles

In this Letter, we report on a crucial experiment showing that magnetic impurities reduce the ferromagnetic order temperature in thiol-capped Au glyconanoparticles (GNPs). The spontaneous magnetization of AuFe GNPs exhibits a fast decrease with temperature that contrasts with the almost constant value of the magnetization observed in Au NPs. Moreover, hysteresis disappears below 300 K. Both features indicate that Fe impurities reduce the high local anisotropy field responsible for the ferromagnetic behavior in Au GNPs. As a consequence, the amazing ferromagnetism in Au NPs should not be associated with the presence of magnetic impurities.

Vitreous SiO2-CaO coatings on Ti6Al4V alloys: reactivity in simulated body fluid versus osteoblast cell culture

Vitreous coatings of the SiO(2)-CaO system have been prepared on Ti6Al4V substrates by the sol-gel method. The textural parameters (porosity and roughness) and thickness of the films obtained increase when the concentration of the precursor solutions is raised. In vitro studies of these coatings have been performed using two approaches: soaking in simulated body fluid, and by growing osteoblasts on these materials. The results of both studies show differences in terms of chemical reactivity. While in simulated body fluid the coatings were dissolved without forming a bioactive surface, when osteoblast-like cells grew on the coatings they were more stable. Furthermore, cell culture assays show biocompatible behavior of these coatings making them of potential interest for clinical applications. The effect of the textural parameters of the obtained coatings on the cell functions (attachment, spreading, proliferation and differentiation) has also been studied. The results show an increase in these cell parameters as the roughness and porosity of the coatings increase.

Origin of orbital ferromagnetism and giant magnetic anisotropy at the nanoscale

The origin of orbital magnetism recently observed in different nanostructured films and particles is discussed as a consequence of spin-orbit coupling. It is shown that contact potentials induced at the thin film surface by broken symmetries, as domain boundaries in self-assembled monolayers, lead to orbital states that in some cases are of large radius. The component of the angular momentum normal to the surface can reach very high values that decrease the total energy by decreasing spin-orbit interaction energy. Intraorbital ferromagnetic spin correlations induce orbital momenta alignment. The estimated values of the magnetic moments per atom are in good agreement with the experimental observations in thiol capped gold films and nanoparticles.

Metallic magnetic nanoparticles

In this paper, we reviewed some relevant aspects of the magnetic properties of metallic nanoparticles with small size (below 4 nm), covering the size effects in nanoparticles of magnetic materials, as well as the appearance of magnetism at the nanoscale in materials that are nonferromagnetic in bulk. These results are distributed along the text that has been organized around three important items: fundamental magnetic properties, different fabrication procedures, and characterization techniques. A general introduction and some experimental results recently obtained in Pd and Au nanoparticles have also been included. Finally, the more promising applications of magnetic nanoparticles in biomedicine are indicated. Special care was taken to complete the literature available on the subject.

Identification of a nuclear export signal in the KSHV latent protein LANA2 mediating its export from the nucleus

LANA2 is a latent protein detected in Kaposi's sarcoma-associated herpesvirus (KSHV)-infected B cells that inhibits p53-dependent transcriptional transactivation and apoptosis and PKR-dependent apoptosis, suggesting an important role in the transforming activity of the virus. It has been reported that LANA2 localizes into the nucleus of both KSHV-infected B cells and transiently transfected HeLa cells. In this study, we show that LANA2 is a nucleocytoplasmic shuttling protein that requires a Rev-type nuclear export signal located in the C-terminus to direct the protein to the cytoplasm, through an association with the export receptor CRM1. In addition, a functional protein kinase B (PKB)/Akt phosphorylation motif partially overlapping with the nuclear export signal was identified. Nuclear exclusion of LANA2 was negatively regulated by the phosphorylation of threonine 564 by Akt. The ability of LANA2 to shuttle between nucleus and cytoplasm has implications for the function of this viral protein.