Up-regulation of neutrophil activating protein in Helicobacter pylori under high-salt stress: Structural and phylogenetic comparison with bacterial iron-binding ferritins

It is generally accepted that most gastrointestinal diseases are probably caused by the bacterial pathogen Helicobacter pylori (H. pylori). In this study we have focused on the comparison of protein expression profiles of H. pylori grown under normal and high-salt conditions by a proteomics approach. We have identified about 190 proteins whose expression levels changed after growth at high salt concentration. Among these proteins, neutrophil-activating protein (NapA) was found to be consistently up-regulated under osmotic stress brought by high salts. We have investigated the effect of high salt on secondary and tertiary structures of NapA by circular dichroism spectroscopy followed by analytical ultracentrifugation to monitor the change of quaternary structure of recombinant NapA with increasing salt concentration. The loss of iron-binding activity of NapA coupled with noticeable energetic variation in protein association of NapA as revealed by isothermal titration calorimetry was found under high salt condition. The phylogenetic tree analysis based on sequence comparison of 16 protein sequences encompassing NapA proteins and ferritin of H. pylori and other prokaryotic organisms pointed to the fact that all H. pylori NapA proteins of human origin are more homologous to NapA of Helicobacter genus than to other bacterial NapA. Based on computer modeling, NapA proteins from H. pylori of human isolates are found more similar to ferritin from H. pylori than to NapA from other species of bacteria. Taken together, these results suggested that divergent evolution of NapA and ferritin possessing dissimilar and diverse sequences follows a path distinct from that of convergent evolution of NapA and ferritin with similar dual functionality of iron-binding and ferroxidase activities.     

p38-MAPK signaling pathway is not involved in osteogenic differentiation during early response of mesenchymal stem cells to continuous mechanical strain

Quercetin has been reported to protect testicular cells from oxidative damage induced by environmental chemicals. In this study, we isolated interstitial Leydig cells (ILCs) from immature rats, set-up ILCs culture, co-treated cells with atrazine (ATZ) and quercetin (QT), evaluated toxicity, and measured the expression levels of antioxidant enzymes and nuclear factor-kappaB (NF-κB) and levels of steroidogenic enzymes. ATZ decreased ILCs viability at concentrations higher than 10 μg/mL and increased reactive oxygen species, malondialdehyde (MDA), and glutathione levels. ATZ also increased glutathione peroxidase, glutathione reductase, and glutathione-S-transferase and decreased superoxide dismutase-1 (sod1) and superoxide dismutase-2 (sod2) messenger RNA (mRNA) levels which were prevented by QT. The changes in the MDA levels and lactate dehydrogenase leakage induced by ATZ (50 μg/mL) were also prevented on co-treatment with QT (50 μM). Furthermore, ATZ-induced 3β- and 17β-hydroxysteroid dehydrogenase activities and NF-κB-expressions at the mRNA and protein levels were also recovered to control value on co-treatment with QT. These data showed that QT protected against ATZ-induced ILCs toxicity by restoring the expression of NF-κB and steroidogenic activity and by preventing the oxidative stress.     

C-reactive protein reduces protein S-nitrosylation in endothelial cells

Glycodelin A (GdA) is a dimeric glycoprotein synthesized by the human endometrium under progesterone regulation. Based on the high sequence similarity with β-lactoglobulin, it is placed under the lipocalin superfamily. The protein is one of the local immunomodulators present at the feto-maternal interface which affects both the innate as well as the acquired arms of the immune system, thereby bringing about successful establishment and progression of pregnancy. Our previous studies revealed that the domain responsible for the immunosuppressive activity of glycodelin lies on its protein backbone and the glycans modulate the same. This study attempts to further delineate the apoptosis inducing region of GdA. Our results demonstrate that the stretch of amino acid sequence between Met24 to Leu105 is necessary and sufficient to inhibit proliferation of T cells and induce apoptosis in them. Further, within this region the key residues involved in harboring the activity were shown to be present between Asp52 and Ser65.     

Genome-wide screen for aberrantly expressed miRNAs reveals miRNA profile signature in breast cancer

Dysregulation in the expression of miRNAs contributes to the occurrence and development of many human cancers. We herein attempted to obtain the potential association between miRNA expression profile and breast cancer by applying high-throughput sequencing technology. Small RNAs from seven paired tumor and adjacent normal tissue samples were sequenced. To determine the miRNA expression profiles in tissues and sera, another five equally pooled serum samples from 20 patients and 30 normal women were sequenced. Despite a similar number in abundantly expressed miRNAs across samples, we detected varying miRNA expression profiles. Some miRNAs showed inconsistent or opposite dysregulation trends across different tumor tissues, including some abundantly expressed miRNA gene clusters and gene families. Wilcoxon sign-rank test for paired samples analysis revealed that abnormal miRNAs showed a higher level of variation across the seven tumor samples. We also completely surveyed abnormal miRNAs expressed in tumor and serum tissues in the mixed datasets based on the relative expression levels. Most of these miRNAs were significantly down-regulated in tumor samples, but nine abnormal miRNAs (miR-18a, 19a, 20a, 30a, 103b, 126, 126*, 192, 1287) were consistently expressed in tumor tissues and serum samples. Based on experimentally validated target mRNAs, functional enrichment analysis indicated that these abnormal miRNAs and miRNA groups (miRNA gene clusters and gene families) have important roles in multiple biological processes. Dynamic miRNA expression profiles, various abnormal miRNA profiles and complexity of the miRNA regulatory network reveal that the miRNA expression profile is a potential biomarker for classifying or detecting human disease.     

Isolated Skull Cryptococcosis in an Immunocompetent Patient

A 62-year-old immunocompetent rural woman who represents an isolated cryptococcal skull infection without systematic involvement is described. Diagnosis was based on positive India ink staining, positive histopathologic examination, and positive culture. Species identification was performed by growth on Sabouraud dextrose agar and CHROMagar medium and by sequencing of the intergenic and internal transcribed spacer regions of the rRNA genes. This case describes a rare presentation of Cryptococcus neoformans infection in a human immunodeficiency virus-negative patient. The lesions were significantly improved with treatment of daily oral itraconazole 400 mg. A maintenance therapy with a low-dose itraconazole was prescribed to warrant a clinical and mycological eradication. A two-year follow-up did not show any recurrence of infection.     

Aly and THO are required for assembly of the human TREX complex and association of TREX components with the spliced mRNA

The mRNA export complex TREX (TREX) is known to contain Aly, UAP56, Tex1 and the THO complex, among which UAP56 is required for TREX assembly. Here, we systematically investigated the role of each human TREX component in TREX assembly and its association with the mRNA. We found that Tex1 is essentially a subunit of the THO complex. Aly, THO and UAP56 are all required for assembly of TREX, in which Aly directly interacts with THO subunits Thoc2 and Thoc5. Both Aly and THO function in linking UAP56 to the cap-binding protein CBP80. Interestingly, association of UAP56 with the spliced mRNA, but not with the pre-mRNA, requires Aly and THO. Unexpectedly, we found that Aly and THO require each other to associate with the spliced mRNA. Consistent with these biochemical results, similar to Aly and UAP56, THO plays critical roles in mRNA export. Together, we propose that Aly, THO and UAP56 form a highly integrated unit to associate with the spliced mRNA and function in mRNA export.