No evidence for DUP25 in patients with panic disorder using a quantitative real-time PCR approach

A duplication of chromosome 15q24-q26 (DUP25) has been reported to be associated with anxiety disorders. We tested for the presence of DUP25 in a sample of 50 patients with panic disorder and 50 controls using a quantitative real-time PCR approach. Contrary to the original finding, our results were compatible with the absence of DUP25, and no significant difference could be detected between patients and controls (P=1.0). Thus, our study does not support the hypothesis of an involvement of DUP25 in panic disorder.     

Finite element method analysis of the tooth movement induced by orthodontic forces

The finite element method is a useful technique for measuring structural stress and for movement analyses. The objective of this investigation was to get a more accurate estimation of tooth movement depending on application point when a tipping orthodontic force is applied. The three-dimensional model of un upper canine, consisting of 4,000 hexahedron elements with 2,367 nodes was obtained. Horizontal, orally directed 1N tipping orthodontic force was applied to the model on five different levels of the tooth crown. The three-dimensional mathematical finite element model is useful in analyzing the tooth movement in response to orthodontic forces. The tipping tooth movement is greater if the force is applied closer to its neck, or more gingivally.     

Effect of NO synthase inhibition on myocardial metabolism during moderate ischemia

Nitric oxide (NO) is involved in the control of myocardial metabolism. In normoperfused myocardium, NO synthase inhibition shifts myocardial metabolism from free fatty acid (FFA) toward carbohydrate utilization. Ischemic myocardium is characterized by a similar shift toward preferential carbohydrate utilization, although NO synthesis is increased. The importance of NO for myocardial metabolism during ischemia has not been analyzed in detail. We therefore assessed the influence of NO synthase inhibition with N(G)-nitro-l-arginine (l-NNA) on myocardial metabolism during moderate ischemia in anesthetized pigs. In control animals, the increase in left ventricular pressure with l-NNA was mimicked by aortic constriction. Before ischemia, l-NNA decreased myocardial FFA consumption (MV(FFA); P < 0.05), while consumption of carbohydrate and O(2) (MVo(2)) remained constant. ATP equivalents [calculated with the assumption of complete oxidative substrate decomposition (ATP(eq))] decreased with l-NNA (P < 0.05), associated with a decrease of regional myocardial function (P < 0.05). In contrast, aortic constriction had no effect on MV(FFA), while MVo(2) increased (P < 0.05) and ATP(eq) and regional myocardial function remained constant. During ischemia, alterations in myocardial metabolism were similar in control and l-NNA-treated animals: MV(FFA) decreased (P < 0.05) and net lactate consumption was reversed to net lactate production (P < 0.05). Regional myocardial function was decreased (P < 0.05), although more markedly in animals receiving l-NNA (P < 0.05). We conclude that the efficiency of oxidative metabolism was impaired by l-NNA per se, paralleled by impaired regional myocardial function. During ischemia, l-NNA had no effect on myocardial substrate consumption, indicating that NO synthases were no longer effectively involved in the control of myocardial metabolism.     

IL-1 receptor type 1 gene-deficient mice demonstrate an impaired host defense against pneumococcal meningitis

The fatality rate associated with Streptococcus pneumoniae meningitis remains high despite adequate antibiotic treatment. IL-1 is an important proinflammatory cytokine, which is up-regulated in brain tissue after the induction of meningitis. To determine the role of IL-1 in pneumococcal meningitis we induced meningitis by intranasal inoculation with 8 x 10(4) CFU of S. pneumoniae and 180 U of hyaluronidase in IL-1R type I gene-deficient (IL-1R(-/-)) mice and wild-type mice. Meningitis resulted in elevated IL-1alpha and IL-1beta mRNA and protein levels in the brain. The absence of an intact IL-1 signal was associated with a higher susceptibility to develop meningitis. Furthermore, the lack of IL-1 impaired bacterial clearance, as reflected by an increased number of CFU in cerebrospinal fluid of IL-1R(-/-) mice. The characteristic pleocytosis of meningitis was not significantly altered in IL-1R(-/-) mice, but meningitis was associated with lower brain levels of cytokines. The mortality was significantly higher and earlier in the course of the disease in IL-1R(-/-) mice. These results demonstrate that endogenous IL-1 is required for an adequate host defense in pneumococcal meningitis.     

Splicing factor SRp30c interaction with Y-box protein-1 confers nuclear YB-1 shuttling and alternative splice site selection

The multifunctional DNA- and RNA-associated Y-box protein 1 (YB-1) specifically binds to splicing recognition motifs and regulates alternative splice site selection. Here, we identify the arginine/serine-rich SRp30c protein as an interacting protein of YB-1 by performing a two-hybrid screen against a human mesangial cell cDNA library. Co-immunoprecipitation studies confirm a direct interaction of tagged proteins YB-1 and SRp30c in the absence of RNA via two independent protein domains of YB-1. A high affinity interaction is conferred through the N-terminal region. We show that the subcellular YB-1 localization is dependent on the cellular SRp30c content. In proliferating cells, YB-1 localizes to the cytoplasm, whereas FLAG-SRp30c protein is detected in the nucleus. After overexpression of YB-1 and FLAG-SRp30c, both proteins are co-localized in the nucleus, and this requires the N-terminal region of YB-1. Heat shock treatment of cells, a condition under which SRp30c accumulates in stress-induced Sam68 nuclear bodies, abrogates the co-localization and YB-1 shuttles back to the cytoplasm. Finally, the functional relevance of the YB-1/SRp30c interaction for in vivo splicing is demonstrated in the E1A minigene model system. Here, changes in splice site selection are detected, that is, overexpression of YB-1 is accompanied by preferential 5' splicing site selection and formation of the 12 S isoform.     

Reactive oxygen species sensitivity of angiotensin II-dependent translation initiation in vascular smooth muscle cells

Translation initiation, the rate-limiting step in protein synthesis, is a key event in vascular smooth muscle cell growth, a major component of vascular disease. Translation initiation is regulated by interaction between PHAS-I and the eukaryotic initiation factor 4E (eIF4E). Although angiotensin II (Ang II)-induced vascular smooth muscle cell hypertrophy requires the generation of reactive oxygen species (ROS), the ROS sensitivity of these events and their upstream activators remain unclear. Here, we investigated the role of ROS in the regulation of PHAS-I phosphorylation on Thr-70 and Ser-65, an event required for the release of eIF4E from PHAS-I. Ang II-induced Ser-65 phosphorylation was ROS-dependent as assessed by pretreatment with ebselen (3.6 +/- 0.2 versus 1.1 +/- 0.2), diphenylene iodonium (3.6 +/- 0.2 versus 1.0 +/- 0.1), and N-acetyl cysteine (3.6 +/- 0.2 versus 1.2 +/- 0.1), but Ang II-stimulated phosphorylation of Thr-70 was ROS-insensitive. Although phosphatidylinositol 3-kinase pathway inhibition by LY294004 blocked both Ser-65 and Thr-70 phosphorylation (3.8 +/- 0.1 versus 0.8 +/- 0.1 and 3.2 +/- 0.2 versus 1.0 +/- 0.01, respectively), protein phosphatase 2A inhibition by okadaic acid selectively increased (3.3 +/- 0.1 versus 5.2 +/- 0.1) and p38 mitogen-activated protein kinase inhibition by SB203580 selectively decreased (3.8 +/- 0.1 versus 1.4 +/- 0.3) Ser-65 phosphorylation. Dominant negative Akt adenovirus also inhibited only Ser-65 phosphorylation (3.7 +/- 0.1 versus 1.0 +/- 0.03). These results demonstrate a unique differential ROS sensitivity of two separate residues on PHAS-I, which seems to be explained by the selective involvement of distinct signaling pathways in the regulation of these phosphorylation events.     

A novel mechanism of pore formation: membrane penetration by the N-terminal amphipathic region of equinatoxin

Equinatoxin II is a representative of actinoporins, eukaryotic pore-forming toxins from sea anemones. It creates pores in natural and artificial lipid membranes by an association of three or four monomers. Cysteine-scanning mutagenesis was used to study the structure of the N terminus, which is proposed to be crucial in transmembrane pore formation. We provide data for two steps of pore formation: a lipid-bound monomeric intermediate state and a final oligomeric pore. Results show that residues 10-28 are organized as an alpha-helix in both steps. In the first step, the whole region is transferred to a lipid-water interface, laying flat on the membrane. In the pore-forming state, the hydrophilic side of the amphipathic helix lines the pore lumen. The pore has a restriction around Asp-10, according to the permeabilization ratio of ions flowing through pores formed by chemically modified mutants. A general model was introduced to derive the tilt angle of the helix from the ion current data. This study reveals that actinoporins use a unique single helix insertion mechanism for pore formation.     

Phosphatidylinositol 3-kinase interacts with the adaptor protein Dab1 in response to Reelin signaling and is required for normal cortical lamination

Reelin is a large secreted signaling protein that binds to two members of the low density lipoprotein receptor family, the apolipoprotein E receptor 2 and the very low density lipoprotein receptor, and regulates neuronal positioning during brain development. Reelin signaling requires activation of Src family kinases as well as tyrosine phosphorylation of the intracellular adaptor protein Disabled-1 (Dab1). This results in activation of phosphatidylinositol 3-kinase (PI3K), the serine/threonine kinase Akt, and the inhibition of glycogen synthase kinase 3beta, a protein that is implicated in the regulation of axonal transport. Here we demonstrate that PI3K activation by Reelin requires Src family kinase activity and depends on the Reelin-triggered interaction of Dab1 with the PI3K regulatory subunit p85alpha. Because the Dab1 phosphotyrosine binding domain can interact simultaneously with membrane lipids and with the intracellular domains of apolipoprotein E receptor 2 and very low density lipoprotein receptor, Dab1 is preferentially recruited to the neuronal plasma membrane, where it is phosphorylated. Efficient Dab1 phosphorylation and activation of the Reelin signaling cascade is impaired by cholesterol depletion of the plasma membrane. Using a neuronal migration assay, we also show that PI3K signaling is required for the formation of a normal cortical plate, a step that is dependent upon Reelin signaling.     

Dishevelled activates Ca2+ flux,PKC, and CamKII in vertebrate embryos

Wnt ligands and Frizzled (Fz) receptors have been shown to activate multiple intracellular signaling pathways. Activation of the Wnt-beta-catenin pathway has been described in greatest detail, but it has been reported that Wnts and Fzs also activate vertebrate planar cell polarity (PCP) and Wnt-Ca2+ pathways. Although the intracellular protein Dishevelled (Dsh) plays a dual role in both the Wnt-beta-catenin and the PCP pathways, its potential involvement in the Wnt-Ca2+ pathway has not been investigated. Here we show that a Dsh deletion construct, XDshDeltaDIX, which is sufficient for activation of the PCP pathway, is also sufficient for activation of three effectors of the Wnt-Ca2+ pathway: Ca2+ flux, PKC, and calcium/calmodulin-dependent protein kinase II (CamKII). Furthermore, we find that interfering with endogenous Dsh function reduces the activation of PKC by Xfz7 and interferes with normal heart development. These data suggest that the Wnt-Ca2+ pathway utilizes Dsh, thereby implicating Dsh as a component of all reported Fz signaling pathways.     

A double test of the parasite manipulation hypothesis in a burrowing bivalve

The parasite manipulation hypothesis predicts that parasites should be selected to manipulate host behaviour to facilitate transmission to the next host. The bivalve Macoma balthica burrows less deep when parasitized by the trematode Parvatrema affinis. Shallow burrowing increases the likelihood of ingestion by birds, their final hosts, and therefore this has been interpreted as manipulation by the parasite. When unparasitized, M. balthica displays seasonal changes in burrowing depth, becoming less accessible to predators in winter. If shallow burrowing of parasitized individuals is due to direct manipulation by the parasite, the availability of parasitized individuals should be high throughout the year, or at least especially in the season when most birds are present and potential transmission rates are highest. We compared burrowing depths of parasitized and unparasitized individuals in a single population during seven consecutive years. Parasitized individuals showed reduced burrowing depths but, in contrast to the prediction, the effect of parasites on availability to predators was smallest, not largest, in the season with the highest bird numbers. The parasite P. affinis competes for energy with the host, and M. balthica with low energy stores are known to reduce depth of burrowing. When we included size-corrected somatic ash-free dry mass (as an estimate of the energy stores) in our statistical analysis, the effect of infection on burrowing depth disappeared. Thus the effect of infection on burrowing depth is likely to be an unavoidable, indirect effect of the channelling of energy towards the parasite, causing the starving individual to take greater risks in the acquisition of food. Since both the seasonal pattern and the magnitude of increased availability of parasitized individuals are inadequate, the increased exposure of parasitized M. balthica to the final host does not seem to represent an example of adaptive host manipulation by the parasite.