Sex-Specific Patterns of Diaphragm Phospholipid Content and Remodeling during Aging and in a Model of SELENON-Related Myopathy

Growing evidence shows that the lipid bilayer is a key site for membrane interactions and signal transduction. Surprisingly, phospholipids have not been widely studied in skeletal muscles, although mutations in genes involved in their biosynthesis have been associated with muscular diseases. Using mass spectrometry, we performed a phospholipidomic profiling in the diaphragm of male and female, young and aged, wild type and SelenoN knock-out mice, the murine model of an early-onset inherited myopathy with severe diaphragmatic dysfunction. We identified 191 phospholipid (PL) species and revealed an important sexual dimorphism in PLs in the diaphragm, with almost 60% of them being significantly different between male and female animals. In addition, 40% of phospholipids presented significant age-related differences. Interestingly, SELENON protein absence was responsible for remodeling of 10% PL content, completely different in males and in females. Expression of genes encoding enzymes involved in PL remodeling was higher in males compared to females. These results establish the diaphragm PL map and highlight an important PL remodeling pattern depending on sex, aging and partly on genotype. These differences in PL profile may contribute to the identification of biomarkers associated with muscular diseases and muscle aging.

Oxidative stress activates red cell adhesion to laminin in sickle cell disease

Vaso-occlusive crises are the hallmark of sickle cell disease (SCD). They are believed to occur in two steps, starting with adhesion of deformable low-dense red blood cells (RBCs), or other blood cells such as neutrophils, to the wall of post-capillary venules, followed by trapping of the denser RBCs or leukocytes in the areas of adhesion because of reduced effective lumen-diameter. In SCD, RBCs are heterogeneous in terms of density, shape, deformability and surface proteins, which accounts for the differences observed in their adhesion and resistance to shear stress. Sickle RBCs exhibit abnormal adhesion to laminin mediated by Lu/BCAM protein at their surface. This adhesion is triggered by Lu/BCAM phosphorylation in reticulocytes but such phosphorylation does not occur in mature dense RBCs despite firm adhesion to laminin. In this study, we investigated the adhesive properties of sickle RBC subpopulations and addressed the molecular mechanism responsible for the increased adhesion of dense RBCs to laminin in the absence of Lu/BCAM phosphorylation. We provide evidence for the implication of oxidative stress in post-translational modifications of Lu/BCAM that impact its distribution and cis-interaction with glycophorin C at the cell surface activating its adhesive function in sickle dense RBCs.

Polyphenols journey through blood-brain barrier towards neuronal protection

Age-related complications such as neurodegenerative disorders are increasing and remain cureless. The possibility of altering the progression or the development of these multifactorial diseases through diet is an emerging and attractive approach with increasing experimental support. We examined the potential of known bioavailable phenolic sulfates, arising from colonic metabolism of berries, to influence hallmarks of neurodegenerative processes. In silico predictions and in vitro transport studies across blood-brain barrier (BBB) endothelial cells, at circulating concentrations, provided evidence for differential transport, likely related to chemical structure. Moreover, endothelial metabolism of these phenolic sulfates produced a plethora of novel chemical entities with further potential bioactivies. Pre-conditioning with phenolic sulfates improved cellular responses to oxidative, excitotoxicity and inflammatory injuries and this attenuation of neuroinflammation was achieved via modulation of NF-κB pathway. Our results support the hypothesis that these small molecules, derived from dietary (poly)phenols may cross the BBB, reach brain cells, modulate microglia-mediated inflammation and exert neuroprotective effects, with potential for alleviation of neurodegenerative diseases.

Bioequivalence studies for two different strengths of montelukast in healthy volunteers: 10 mg film-coated tablets and 5 mg chewable tablets

In order to assess the bioequivalence of 2 different formulations of montelukast, a pivotal trial for the montelukast 10 mg film-coated tablets formulation and a pivotal trial for the montelukast 5 mg chewable tablets formulation were conducted.For the 10 mg study, 34 healthy subjects were enrolled in a single centre, randomised, single-dose, open-label, 2-way crossover study, with a minimum washout period of 7 days, while for the 5 mg study, 42 healthy subjects were included in another study with a similar design. For both studies, plasma samples were collected up to 24 h post-dosing and drug levels were determined by reverse liquid chromatography and detected by tandem mass spectrometry detection.Pharmacokinetic parameters used for bioequivalence assessment, area under the concentration-time curve from time zero to time of last non-zero concentration (AUC0-t) and from time zero to infinity (AUC0-inf) and maximum observed concentration (Cmax), were determined from the drug concentration data using non-compartmental analysis.In the 10 mg study, the 90% confidence intervals obtained by analysis of variance were 99.62-120.51% for Cmax, 102.25-117.37% for AUC0-t and 101.96-116.67% for AUC0-inf, which were within the predefined acceptable range of 80.00-125.00%.In the 5 mg study, the 90% confidence intervals were 91.14-98.46% for Cmax, 93.02-98.42% for AUC0-t and 93.09-98.63% for AUC0-inf, which were within the predefined acceptable range of 80.00-125.00%.Bioequivalence between formulations was concluded both in terms of rate and extent of absorption for both strengths.

Bioequivalence of two formulations of escitalopram

Escitalopram, CAS registry number 128196-01-0 is an orally administrated selective serotonin reuptake inhibitor (SSRI).The objective of this trial was to assess bioequivalence between an escitalopram formulation manufactured by Grupo Tecnimede and that of a European reference formulation, while evaluating both formulations' tolerability as a secondary objective.24 healthy subjects were enrolled in a single centre, randomised, single-dose, open-label, 2-way crossover study. Drug levels were determined by reverse liquid chromatography and detected by tandem mass spectrometry detection, LC-MS/MS method. Pharmacokinetic parameters used for bioequivalence assessment were determined from the drug concentration data using non-compartmental analysis.Mean±Standard deviation (SD) Cmax values were 18.89±5.06 ng/mL and 18.45±5.05 ng/mL for reference and test, respectively. AUClast was 577.16±196.20 ng · h/mL after the administration of the reference and 577.69±220.88 ng · h/mL for the test. AUCinf was 595.66±203.80 ng · h/mL after the administration of the reference 596.19±235.47 ng · h/mL for the test.The 90% confidence intervals obtained by analysis of variance were 92.38-103.38% for Cmax, 94.10-104.37% for AUClast and 93.80-104.09% for AUCinf, which were within the predefined acceptable range of 80.00-125.00%. Both formulations were well tolerated, with no major side effects and no relevant differences in safety profiles observed between the preparations.The design of the study was adequate to determine the pharmacokinetic parameters of the test and the reference formulations. Bioequivalence between formulations was concluded both in terms of rate and extent of absorption.

Genetic inactivation of the laminin alpha5 chain receptor Lu/BCAM leads to kidney and intestinal abnormalities in the mouse

Lutheran blood group and basal cell adhesion molecule (Lu/BCAM) has been recognized as a unique receptor for laminin alpha5 chain in human red blood cells and as a coreceptor in epithelial, endothelial, and smooth muscle cells. Because limited information is available regarding the function of this adhesion glycoprotein in vivo, we generated Lu/BCAM-null mice and looked for abnormalities in red blood cells as well as in kidney and intestine, two tissues showing alteration in laminin alpha5 chain-deficient mice. We first showed that, in contrast to humans, wild-type murine red blood cells failed to express Lu/BCAM. Lu/BCAM-null mice were healthy and developed normally. However, although no alteration of the renal function was evidenced, up to 90% of the glomeruli from mutant kidneys exhibited abnormalities characterized by a reduced number of visible capillary lumens and irregular thickening of the glomerular basement membrane. Similarly, intestine analysis of mutant mice revealed smooth muscle coat thickening and disorganization. Because glomerular basement membrane and smooth muscle coat express laminin alpha5 chain and are in contact with cell types expressing Lu/BCAM in wild-type mice, these results provide evidence that Lu/BCAM, as a laminin receptor, is involved in vivo in the maintenance of normal basement membrane organization in the kidney and intestine.

Structure-function analysis of the extracellular domains of the Duffy antigen/receptor for chemokines: characterization of antibody and chemokine binding sites

The Duffy antigen/receptor for chemokines (DARC), a seven-transmembrane glycoprotein carrying the Duffy (Fy) blood group, acts as a widely expressed promiscuous chemokine receptor. In a structure-function study, we analysed the binding of chemokines and anti-Fy monoclonal antibodies (mAbs) to K562 cells expressing 39 mutant forms of DARC with alanine substitutions spread out on the four extracellular domains (ECDs). Using synthetic peptides, we defined previously the Fy6 epitope (22-FEDVW-26), and we characterized the Fya epitope as the linear sequence 41-YGANLE-46. In agreement with these results, mutations of F22-E23, V25 and Y41, G42, N44, L45 on ECD1 abolished the binding of anti-Fy6 and anti-Fya mAbs to K562 cells respectively, Anti-Fy3 binding was abolished by D58-D59 (ECD1), R124 (ECD2), D263 and D283 (ECD4) substitutions. Mutations of C51 (ECD1), C129 (ECD2), C195 (ECD3) and C276 (ECD4 severely reduced anti-Fy3 and CXC-chemokine ligand 8 (CXCL-8) binding. CXCL-8 binding was also abrogated by mutations of F22-E23, P50 (ECD1) and D263, R267, D283 (ECD4). These results defined the Fya epitope and suggested that (1) two disulphide bridges are involved in the creation of an active chemokine binding pocket; (2) a limited number of amino acids in ECDs 1-4 participate in CXCL-8 binding; and (3) Fy3 is a conformation-dependent epitope involving all ECDs. We also showed that N-glycosylation of DARC occurred on N16SS and did not influence antibody and chemokine binding.

Cationic liposomes for gene delivery: from biophysics to biological applications

The use of an efficient carrier for nucleic acid-based medicines is considered to be a determinant factor for the successful application of gene therapy. The drawbacks associated with the use of viral vectors, namely those related with safety problems, have prompted investigators to develop alternative methods for gene delivery, cationic lipid-based systems being the most representative. Despite extensive research in the last decade on the use of cationic liposomes as gene transfer vectors and the development of elegant strategies to enhance their biological activity, these systems are still far from being viable alternatives to the use of viral vectors in gene therapy. In this review considerations are made regarding the structure-activity relationships of cationic liposome/DNA complexes and the key formulation parameters influencing the features of lipoplexes are presented and discussed in terms of their effect on biological activity. Particular emphasis is given to the interaction of the lipoplexes with serum components as well as to novel strategies developed to circumvent difficulties that may emerge upon iv administration of the complexes. Finally, since the ability of the lipoplexes to be stored while preserving their transfection activity is a crucial issue for the repeated use of such carriers, approaches reported on the improvement of their physical stability are also reviewed.

Transcriptional regulation in megakaryocytes: the thrombopoietin receptor gene as a model

The MPL gene codes for the thrombopoietin receptor, whose ligand specifically controls megakaryocytic differentiation. In order to understand the molecular basis for the megakaryocyte-specific expression of MPL, we analyzed the regulatory elements of this gene. Two regions are hypersensitive to DNase I in nuclei of cells that express MPL: the promoter and a portion of intron 6. The latter behaves as a chromatin-dependent enhancer. A 200 bp fragment of the promoter is sufficient for high-level specific expression. This fragment can bind several transacting factors in vitro, including GATA-1 and members of the Ets family. GATA-1 binds with low affinity to a unique GATA motif at -70 in the MPL promoter, and destruction of this site yields only a modest decrease in expression level in human erythroleukemia (HEL) cells. Ets proteins also bind with low affinity to two sites. One is located at position -15 and its destruction reduces expression to 50%; the other is located immediately downstream of the GATA motif and plays a crucial role in expression of the promoter in HEL cells, as its inactivation reduces expression to 15%. This study indicates a molecular basis for the coregulation of markers of megakaryocyte differentiation. Finally, we describe other nuclear factor binding sites that may be involved in the cell-type-specific expression of MPL.

Macrothrombocytopenia with abnormal demarcation membranes in megakaryocytes and neutropenia with a complete lack of sialyl-Lewis-X antigen in leukocytes--a new syndrome?

A new megathrombocytopenic syndrome with giant platelets in peripheral blood and severe thrombocytopenia was diagnosed in a 4-month-old boy. His clinical course included repeated hemorrhagic incidents leading to death at age 37 months. Bone marrow ultrastructural analysis revealed numerous dystrophic megakaryocytes with giant membrane complexes. Although these features were similar to those described for megakaryocytes in mice lacking the gene for transcription factor p45-NF-E2, no abnormalities in the p45-NF-E2 gene could be documented. Platelet membrane analysis showed a reduction in glycoprotein (GP) Ib, but normal content of GPIIb and GPIIIa. Analysis of genes encoding for GPIb alpha and beta, GPV, and GPIX ruled out the possibility that the observed platelet abnormality is a variant of Bernard-Soulier syndrome. A moderate neutropenia was associated with a complete lack of expression of sialyl-Lewis-X on the surface of polymorphonuclear neutrophils. A common defect in posttranslational modification of glycoproteins could account for the diverse cellular abnormalities.

Regulation of embryonic/fetal globin genes by nuclear hormone receptors: a novel perspective on hemoglobin switching

The CCAAT box is one of the conserved motifs found in globin promoters. It binds the CP1 protein. We noticed that the CCAAT-box region of embryonic/fetal, but not adult, globin promoters also contains one or two direct repeats of a short motif analogous to DR-1 binding sites for non-steroid nuclear hormone receptors. We show that a complex previously named NF-E3 binds to these repeats. In transgenic mice, destruction of the CCAAT motif within the human epsilon-globin promoter leads to substantial reduction in epsilon expression in embryonic erythroid cells, indicating that CP1 activates epsilon expression; in contrast, destruction of the DR-1 elements yields striking epsilon expression in definitive erythropoiesis, indicating that the NF-E3 complex acts as a developmental repressor of the epsilon gene. We also show that NF-E3 is immunologically related to COUP-TF orphan nuclear receptors. One of these, COUP-TF II, is expressed in embryonic/fetal erythroid cell lines, murine yolk sac, intra-embryonic splanchnopleura and fetal liver. In addition, the structure and abundance of NF-E3/COUP-TF complexes vary during fetal liver development. These results elucidate the structure as well as the role of NF-E3 in globin gene expression and provide evidence that nuclear hormone receptors are involved in the control of globin gene switching.

[Murine typhus in Portugal]

Murine typhus or endemic typhus is a wide spread infectious disease, with a low prevalence in developed countries, but surely underdiagnosed. Its relative benignity, the similarity to other infectious diseases and the discretion of its epidemiologic chain, as well as the usual unexpectedness of its existence, makes its diagnosis more difficult. The clinical presentation and evolution of this case illustrate the necessity of being aware of this nosological entity.

p45 NF-E2 regulates expression of thromboxane synthase in megakaryocytes

Transcription factor p45 NF-E2 is highly expressed in the erythroid and megakaryocytic lineages. Although p45 recognizes regulatory regions of several erythroid genes, mice deficient for this protein display only mild dyserythropoiesis but have abnormal megakaryocytes and lack circulating platelets. A number of megakaryocytic marker genes have been extensively studied, but none of them is regulated by NF-E2. To find target genes for p45 NF-E2 in megakaryopoiesis, we used an in vivo immunoselection assay: genomic fragments bound to p45 NF-E2 in the chromatin of a megakaryocytic cell line were immunoprecipitated with an anti-p45 antiserum and cloned. One of these fragments belongs to the second intron of the thromboxane synthase gene (TXS). We demonstrate that the TXS gene, which is mainly expressed in megakaryocytes, is indeed directly regulated by p45 NF-E2. First, its promoter contains a functional NF-E2 binding site; second, the intronic NF-E2 binding site is located within a chromatin-dependent enhancer element; third, p45-null murine megakaryocytes do not express detectable TXS mRNA, although TXS expression can be detected in other cells. These data, and the structure of the TXS promoter and enhancer, suggest that TXS belongs to a distinct subgroup of genes involved in platelet formation and function.

Analysis of the thrombopoietin receptor (MPL) promoter implicates GATA and Ets proteins in the coregulation of megakaryocyte-specific genes

The MPL gene codes for the thrombopoietin receptor, whose ligand specifically controls megakaryocytic differentiation. To understand the molecular basis for the megakaryocyte-specific expression of MPL, we analyzed the promoter of this gene. A 200 bp fragment is sufficient for high-level specific expression. This fragment can bind several trans-acting factors in vitro, including GATA-1 and members of the Ets family. GATA-1 binds with low affinity to a unique GATA motif at -70 in the MPL promoter, and destruction of this site yields only a modest decrease in expression level in HEL cells. Ets proteins also bind with low affinity to two sites. One is located at position -15 and its destruction reduces expression to 50%; the other is located immediately downstream of the GATA motif and plays a crucial role in expression of the promoter in HEL cells, as its inactivation reduces expression to 15%. Furthermore, GATA-1 and two Ets proteins, Ets-1 and Fli-1, can trans-activate the MPL promoter in heterologous cells. The effects of GATA-1 and these two Ets proteins are additive. Together with our previous results on the glycoprotein IIb (GpIIb) promoter, this study indicates a molecular basis for the coregulation of early markers of megakaryocyte differentiation.

[Seroprevalence of Coxiella burnetii and Rickettsia conorii infection in the province of Soria]

BACKGROUND

Determine the antibodies prevalence against Coxiella burnetii and Rickettsia conorii in Soria (Spain).

METHODS

By an indirect immunofluorescence test we examined sera samples for antibodies (IgG, IgM and IgA) against C. burnetii (phase II, formolized antigen) and R. conorii (moroccan strain). The test has been applied to 298 sera (150 men and 148 women) from Soria (Spain). The age of the study population ranged between 2 and 91 years. The results were considered positive when the titres were greater than or equal to 1/80 for C. burnetii and 1/40 for R. conorii.

RESULTS

Antibodies against C. burnetii were present in 20.8% of the examined sera, 8.8% for women (13/148) and 32.7% for men (49/150). We demonstrated titers of antibodies upper to 1/40 in all age groups, and a greater number of positive results in the persons older than 40 years old (p = 0.0001). In all areas we detected positive results and in many of these areas, the positivity was high (38%). We demonstrated positive results against R. conorii in 5% of the people (4.7% for women and 5.3% for men). More than 90% of the positive cases was present in the eastern part of Soria, and in an small area, the positivity was 20%.

CONCLUSIONS

These results confirm a high prevalence of antibodies against C. burnetii in the Soria people, and the existence of R. conorii infection in this area of Spain with a particular distribution. We believe that it is very important to establish an epidemiological surveillance for the detection of clinic cases.