Heat shock factor 1 in brain tumors: a link with transient receptor potential channels TRPV1 and TRPA1

Journal of Molecular Histology - Novel data report a “cross-talk” between Heat-Shock Factor 1 (HSF1) and the transient receptor potential vanilloid 1 cation channel (TRPV1) located in...     

Characterization of microsatellite loci in the European pond turtle Emys orbicularis

A set of eight highly polymorphic microsatellite markers was isolated and characterized from a genomic library enriched for dinucleotide repeats in the European pond turtle, Emys orbicularis. The markers were tested for polymorphism in a total of 33 turtles sampled in two natural ponds in the nature reserve of Kerkini, northern Greece. Number of alleles varied from 10 to 18, and expected heterozygosity ranged between 0.738 and 0.921. This novel set of loci will be particularly useful to assess fine-scale population structure and for parentage analysis in E. orbicularis.     

Cytosine methyltransferases as tumor markers

Changes in DNA methylation patterns is a prominent characteristic of human tumors. Tumor cells display reduced levels of genomic DNA methylation and site-specific CpG island hypermethylation. Methylation of CpG dinucleotides is catalyzed by the enzyme family of DNA methyltransferases (DNMTs). In this review, the role of DNA methylation and DNMTs as key determinants of carcinogenesis is further elucidated. The chromatin modifying proteins that are known to interact with DNMTs are also described. Finally, the role of DNMTs as potential therapeutic targets is addressed.     

Reporting distress and quality of life of patients with diabetes mellitus in primary and secondary care in Greece

Background and aim This study constitutes an initial attempt at elucidating the relationship between quality of life (QoL), health status and psychological distress in patients with diabetes mellitus (DM) in Greece, by comparing patients with DM registered at a rural primary healthcare centre (PHCC) and those attending a diabetes outpatient clinic (DOC) at an urban hospital.Methods Cross-sectional study. Participants were consecutive, consenting patients with a known history of type 2DM(T2 DM), currently registered at either of the two centres. All patients were administered the Short Form-36 version 2 (SF-36 v2) and the Problem Areas In Diabetes (PAID) questionnaire, and information in relation to socio-demographic data and clinical characteristics were also obtained.Results Patients with DM had a lower QoL over all domains when compared with general population normative data. In addition, mean scores for the SF-36 v2 Physical Component Summary (PCS) and Mental Component Summary (MCS) and six subscales of the SF-36 v2 demonstrated significant differences between the two participating centres (P < 0.0001). The mean PAID score was 19.18 (±15.58) for patients from the PHCC, versus 40.19 (±17.36) for the DOC (P < 0.0001). Lower scores on the MCS of the SF-36 v2, and higher scores on PAID in patients with T2 DM were related to major co-morbidities, insulin use and duration of DM.Conclusions Patients with T2 DM from the urban DOC had significantly higher levels of distress and consequently lower levels of QoL compared with patients from the rural PHCC. The findings from this study may have important implications with regard to the individualisation of patient care in Greece, and encouragement of patient participation in the treatment process.     

MANTIS: a phylogenetic framework for multi-species genome comparisons

MOTIVATION: Practitioners of comparative genomics face huge analytical challenges as whole genome sequences and functional/expression data accumulate. Furthermore, the field would greatly benefit from a better integration of this wealth of data with evolutionary concepts. RESULTS: Here, we present MANTIS, a relational database for the analysis of (i) gains and losses of genes on specific branches of the metazoan phylogeny, (ii) reconstructed genome content of ancestral species and (iii) over- or under-representation of functions/processes and tissue specificity of gained, duplicated and lost genes. MANTIS estimates the most likely positions of gene losses on the true phylogeny using a maximum-likelihood function. A user-friendly interface and an extensive query system allow to investigate questions pertaining to gene identity, phylogenetic mapping and function/expression parameters. AVAILABILITY: MANTIS is freely available at http://www.mantisdb.org and constitutes the missing link between multi-species genome comparisons and functional analyses.     

Cytokeratin 18 interacts with the enteropathogenic Escherichia coli secreted protein F (EspF) and is redistributed after infection

Enteropathogenic Escherichia coli (EPEC) pathogenesis requires the delivery of effector proteins into host cytosol by a type III secretion system. The effector protein EspF, while critical for disruption of epithelial barrier function through alteration of tight junctions, is not required for bacterial viability or attachment. Yeast two-hybrid analyses revealed host intermediate filament (IF) protein cytokeratin 18 (CK18) as an interacting partner of EspF. This was confirmed by co-immunoprecipitation of extracts from EPEC-infected epithelial cells. EPEC infection increased detergent-soluble CK18 amounts without significantly altering CK18 expression. The adaptor protein 14-3-3 binds to CK18 and modulates its solubility. EPEC infection promoted CK18/14-3-3 interactions, corresponding to the increase of CK18 in the soluble fractions. 14-3-3 also co-immunoprecipitated with EspF, suggesting that CK18, 14-3-3 and EspF may form a complex in infected cells. The 14-3-3zeta isoform was co-immunoprecipitated with CK18, suggesting the involvement of specific signalling pathways. Immunofluorescence studies revealed a dramatic alteration in the architecture of the IF network in EPEC-infected epithelial cells. IF fragmentation, evident at 2 h post infection, progressed to a collapse of this network at later time points. The secretion mutant (DeltaescN) failed to alter CK18 solubility and IF morphology, while deletion of espF partially impaired the ability of EPEC to induce CK18 modifications. These results suggest that modifications in 14-3-3 interactions and IF network, modulated by type III secreted proteins, may be an important step in EPEC pathogenesis.     

PKC zeta participates in activation of inflammatory response induced by enteropathogenic E. coli

We showed previously that enteropathogenic Escherichia coli (EPEC) infection of intestinal epithelial cells induces inflammation by activating NF-B and upregulating IL-8 expression. We also reported that extracellular signal-regulated kinases (ERKs) participate in EPEC-induced NF-B activation but that other signaling molecules such as PKC may be involved. The aim of this study was to determine whether PKC is activated by EPEC and to investigate whether it also plays a role in EPEC-associated inflammation. EPEC infection induced the translocation of PKC from the cytosol to the membrane and its activation as determined by kinase activity assays. Inhibition of PKC by the pharmacological inhibitor rottlerin, the inhibitory myristoylated PKC pseudosubstrate (MYR-PKC-PS), or transient expression of a nonfunctional PKC significantly suppressed EPEC-induced IB phosphorylation. Although PKC can activate ERK, MYR-PKC-PS had no effect on EPEC-induced stimulation of this pathway, suggesting that they are independent events. PKC can regulate NF-B activation by interacting with and activating IB kinase (IKK). Coimmunoprecipitation studies showed that the association of PKC and IKK increased threefold 60 min after infection. Kinase activity assays using immunoprecipitated PKC-IKK complexes from infected intestinal epithelial cells and recombinant IB as a substrate showed a 2.5-fold increase in IB phosphorylation. PKC can also regulate NF-B by serine phosphorylation of the p65 subunit. Serine phosphorylation of p65 was increased after EPEC infection but could not be consistently attenuated by MYR-PKC-PS, suggesting that other signaling events may be involved in this particular arm of NF-B regulation. We speculate that EPEC infection of intestinal epithelial cells activates several signaling pathways including PKC and ERK that lead to NF-B activation, thus ensuring the proinflammatory response. inflammation; enteropathogenic Escherichia coli; nuclear factor-B; protein kinase C; IB kinase; extracellular signal-regulated kinase     

Evidence for male dispersal along the coasts but no migration in pelagic waters in dusky dolphins (Lagenorhynchus obscurus)

Using nine nuclear species-specific microsatellite loci and two mitochondrial gene fragments (cytochrome b and control region), we investigated the processes that have shaped the geographical distribution of genetic diversity exhibited by contemporary dusky dolphin (Lagenorhynchus obscurus) populations. A total of 221 individuals from four locations (Peru, Argentina, southern Africa, and New Zealand) were assayed, covering most of the species’ distribution range. Although our analyses identify a general demographic decline in the Peruvian dusky dolphin stock (recently affected by high natural and human-induced mortality levels), comparison between the different molecular markers hint at an ancient bottleneck that predates recent El Niño oscillations and human exploitation. Moreover, we find evidence of a difference in dispersal behaviour of dusky dolphins along the South American coast and across the Atlantic. While data in Peruvian and Argentine waters are best explained by male-specific gene flow between these two populations, our analyses suggest that dusky dolphins from Argentina and southern Africa recently separated from an ancestral Atlantic population and, since then, diverged without considerable gene flow. The inclusion of a few New Zealand samples further confirms the low levels of genetic differentiation among most dusky dolphin populations. Only the Peruvian dusky dolphin stock is highly differentiated, especially at mitochondrial loci, suggesting that major fluctuations in its population size have led to an increased rate of genetic drift.     

IL-10-independent STAT3 activation by Toxoplasma gondii mediates suppression of IL-12 and TNF-alpha in host macrophages

Infection of mouse macrophages by Toxoplasma gondii renders the cells resistant to proinflammatory effects of LPS triggering. In this study, we show that cell invasion is accompanied by rapid and sustained activation of host STAT3. Activation of STAT3 did not occur with soluble T. gondii extracts or heat-killed tachyzoites, demonstrating a requirement for live parasites. Parasite-induced STAT3 phosphorylation and suppression of LPS-triggered TNF-alpha and IL-12 was intact in IL-10-deficient macrophages, ruling out a role for this anti-inflammatory cytokine in the suppressive effects of T. gondii. Most importantly, Toxoplasma could not effectively suppress LPS-triggered TNF-alpha and IL-12 synthesis in STAT3-deficient macrophages. These results demonstrate that T. gondii exploits host STAT3 to prevent LPS-triggered IL-12 and TNF-alpha production, revealing for the first time a molecular mechanism underlying the parasite's suppressive effect on macrophage proinflammatory cytokine production.