Spondylocheiro dysplastic form of the Ehlers-Danlos syndrome--an autosomal-recessive entity caused by mutations in the zinc transporter gene SLC39A13

We present clinical, radiological, biochemical, and genetic findings on six patients from two consanguineous families that show EDS-like features and radiological findings of a mild skeletal dysplasia. The EDS-like findings comprise hyperelastic, thin, and bruisable skin, hypermobility of the small joints with a tendency to contractures, protuberant eyes with bluish sclerae, hands with finely wrinkled palms, atrophy of the thenar muscles, and tapering fingers. The skeletal dysplasia comprises platyspondyly with moderate short stature, osteopenia, and widened metaphyses. Patients have an increased ratio of total urinary pyridinolines, lysyl pyridinoline/hydroxylysyl pyridinoline (LP/HP), of approximately 1 as opposed to approximately 6 in EDS VI or approximately 0.2 in controls. Lysyl and prolyl residues of collagens were underhydroxylated despite normal lysyl hydroxylase and prolyl 4-hydroxylase activities; underhydroxylation was a generalized process as shown by mass spectrometry of the alpha1(I)- and alpha2(I)-chain-derived peptides of collagen type I and involved at least collagen types I and II. A genome-wide SNP scan and sequence analyses identified in all patients a homozygous c.483_491 del9 SLC39A13 mutation that encodes for a membrane-bound zinc transporter SLC39A13. We hypothesize that an increased Zn(2+) content inside the endoplasmic reticulum competes with Fe(2+), a cofactor that is necessary for hydroxylation of lysyl and prolyl residues, and thus explains the biochemical findings. These data suggest an entity that we have designated "spondylocheiro dysplastic form of EDS (SCD-EDS)" to indicate a generalized skeletal dysplasia involving mainly the spine (spondylo) and striking clinical abnormalities of the hands (cheiro) in addition to the EDS-like features.     

Regulation of tumor phenotypes by caveolin-1 and sphingolipid-controlled membrane signaling complexes

Aberrant (glyco)sphingolipid expression deeply affects several properties of tumor cells that are involved in tumor progression and metastasis formation: cell adhesion (to the extracellular matrix or to the endothelium of blood vessels), motility, recognition and invasion of host tissues. In particular, (glyco)sphingolipids might contribute to the modulation of integrin-dependent interactions of tumor cells (determining their adhesion, motility and invasiveness) with the extracellular matrix as well as with host cells present in the stromal compartment of the tumor. A model based on solid experimental evidence has been proposed: (glyco)sphingolipids at the cell surface interact with plasma membrane receptors (e.g., integrin receptors and growth factor receptors) and adapter molecules (including tetraspanins) forming signaling complexes that are able to influence the activity of signal transduction molecules oriented at the cytosolic surface of the plasma membrane (mainly the Src kinases pathway members). The function of these signaling complexes appears to be strictly dependent on their (glyco)sphingolipid composition, and likely on specific sphingolipid-protein interactions. From this point of view, particularly intriguing is the connection between (glyco)sphingolipids and caveolin-1, a membrane protein that plays multiple roles as a suppressor of tumor growth and metastasis in ovarian, breast and colon human carcinomas.     

Helicobacter pyloril-asparaginase: a promising chemotherapeutic agent

Bacterial l-asparaginases are amidohydrolases that catalyse the conversion of l-asparagine to l-aspartate and ammonia and are used as anti-cancer drugs. The current members of this class of drugs have several toxic side effects mainly due to their associated glutaminase activity. In the present study, we report the molecular cloning, biochemical characterisation and in vitro cytotoxicity of a novel l-asparaginase from the pathogenic strain Helicobacter pylori CCUG 17874. The recombinant enzyme showed a strong preference for l-asparagine over l-glutamine and, in contrast to most l-asparaginases, it exhibited a sigmoidal behaviour towards l-glutamine. The enzyme preserved full activity after 2 h incubation at 45 °C. In vitro cytotoxicity assays revealed that different cell lines displayed a variable sensitivity towards the enzyme, AGS and MKN28 gastric epithelial cells being the most affected. These findings may be relevant both for the interpretation of the mechanisms underlying H. pylori associated diseases and for biomedical applications.     

Gadd45 beta forms a homodimeric complex that binds tightly to MKK7

Gadd45α, β, and γ proteins, also known as growth arrest and DNA damage-inducible factors, have a number of cellular functions, including cell-cycle regulation and propagation of signals produced by a variety of cellular stimuli, maintaining genomic stability and apoptosis. Furthermore, Gadd45β has been indicated as a major player in the endogenous NF-κB-mediated resistance to apoptosis in a variety of cell lines. In fibroblasts this mechanism involves the inactivation of MKK7, the upstream activator of JNK, by direct binding within the kinase ATP pocket. On the basis of a number of experimental data, the structures of Gadd45β and the Gadd45β-MKK7 complex have been predicted recently and data show that interactions are mediated by acidic loops 1 and 2, and helices 3 and 4 of Gadd45β. Here, we provide further evidence that Gadd45β is a prevailingly α-helical protein and that in solution it is able to form non covalent dimers but not higher-order oligomers, in contrast to what has been reported for the homologous Gadd45α. We show that the contact region between the two monomers is comprised of the predicted helix 1 (residues Q17-Q33) and helix 5 (residues K131-R146) of the protein, which appear to be antiparallel and to form a large dimerisation surface not involved in MKK7 recognition. The results suggest the occurrence of a large complex containing at least an MKK7-Gadd45β:Gadd45β-MKK7 tetrameric unit whose complexity could be further increased by the dimeric nature of the isolated MKK7.     

Activation of nociceptin/orphanin FQ-NOP receptor system inhibits tyrosine hydroxylase phosphorylation, dopamine synthesis, and dopamine D(1) receptor signaling in rat nucleus accumbens and dorsal striatum

Nociceptin/orphanin FQ (N/OFQ) has been reported to inhibit dopamine (DA) release in basal ganglia mainly by acting on NOP receptors in substantia nigra and ventral tegmental area. We investigated whether N/OFQ could affect DA transmission by acting at either DA nerve endings or DA-targeted post-synaptic neurons. In synaptosomes of rat nucleus accumbens and striatum N/OFQ inhibited DA synthesis and tyrosine hydroxylase (TH) phosphorylation at Ser40 via NOP receptors coupled to inhibition of the cAMP/protein kinase A pathway. Immunofluorescence studies showed that N/OFQ preferentially inhibited phospho-Ser40-TH in nucleus accumbens shell and that in this subregion NOP receptors partly colocalized with either TH or DA D(1) receptor positive structures. In accumbens and striatum N/OFQ inhibited DA D(1) receptor-stimulated cAMP formation, but failed to affect either adenosine A(2A) or DA D(2) receptor regulation of cAMP. In accumbens slices, N/OFQ inhibited DA D(1)-induced phosphorylation of NMDA and alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate glutamate receptors, whereas in primary cultures of accumbal cells, which were found to coexpress NOP and DA D(1) receptors, N/OFQ curtailed DA D(1) receptor-induced cAMP-response element-binding protein phosphorylation. Thus, in accumbens and striatum N/OFQ exerts an inhibitory constraint on DA transmission by acting on either pre-synaptic NOP receptors inhibiting TH phosphorylation and DA synthesis or post-synaptic NOP receptors selectively down-regulating DA D(1) receptor signaling.     

The impact of the invasive Ponto-Caspian amphipod <Emphasis Type="Italic">Pontogammarus robustoides</Emphasis> on littoral communities in Lithuanian lakes

The intentionally introduced Pontogammarus robustoides is the most successful amphipod invader of Lithuanian inland waters and has become established in large lakes. Its impact on littoral invertebrate communities was studied by comparing similar habitats across lakes that harbour or are devoid of the invader. In habitats where P. robustoides is well established and numerous, it significantly reduces species richness and community diversity. Moderate pontogammarid density in habitats that can sustain the native gammarid Gammarus lacustris, however, revealed no negative impact on diversity metrics. Among the lakes studied, the benthic biomass did not differ in invaded and uninvaded habitats. The biomass of indigenous invertebrates (excluding chironomids, which exhibited high lake-specific biomass variation) was lower in the places with well-established P. robustoides. A detrimental impact was observed upon the native isopod Asellus aquaticus and a negative correlation with most of the higher taxa of native invertebrates. In the invaded lake habitats that favour P. robustoides, a change in community structure and a decrease in diversity up to twofold or more are to be expected.     

Interleukin-18 and gestosis: correlation with Helicobacter pylori seropositivity

The aim of this brief communication was to determine the correlation between pre-eclampsia (PE), Helicobacter pylori pathogenic strains seropositivity, and interleukin-18 (IL-18) levels. To this purpose 25 pre-eclamptic women and 25 healthy parturient women of similar age were evaluated for: IL-18 levels, by ELISAH. pylori seropositivity, by anti-IgG ELISAAnti-Cag-A antibodies using a commercial immunoblot assay.We report similar values of IL-18 in our pre-eclamptic patients and in healthy parturient women (respectively 350 +/- 150 vs. 399 +/- 132 pg ml(-1); p = 0.23). However the seropositivity for H. pylori was 84 and 32% (p < 0.001), and anti-Cag-A antibodies were present respectively in 80 and 28% of the two populations. On the basis of our data we hypothesize that H. pylori infection from Cag-A strains can be involved in some cases of PE and that the microorganism could modulate IL-18 release. In fact, differences on IL-18 production have been described by different authors between pre-eclamptic and healthy pregnant women, independently from infective pathology.