RbAp48 Protein Is a Critical Component of GPR158/OCN Signaling and Ameliorates Age-Related Memory Loss

Precisely deciphering the molecular mechanisms of age-related memory loss is crucial to create appropriate therapeutic interventions. We have previously shown that the histone-binding protein RbAp48/Rbbp4 is a molecular determinant of Age-Related Memory Loss. By exploring how this protein regulates the genomic landscape of the hippocampal circuit, we find that RbAp48 controls the expression of BDNF and GPR158 proteins, both critical components of osteocalcin (OCN) signaling in the mouse hippocampus. We show that inhibition of RbAp48 in the hippocampal formation inhibits OCN’s beneficial functions in cognition and causes deficits in discrimination memory. In turn, disruption of OCN/GPR158 signaling leads to the downregulation of RbAp48 protein, mimicking the discrimination memory deficits observed in the aged hippocampus. We also show that activation of the OCN/GPR158 pathway increases the expression of RbAp48 in the aged dentate gyrus and rescues age-related memory loss

Evaluation of six CTLA-4 polymorphisms in high-risk melanoma patients receiving adjuvant interferon therapy in the He13A/98 multicenter trial

<p>ABSTRACT</p> <p>Purpose</p> <p>Interferon is approved for adjuvant treatment of patients with stage IIb/III melanoma. The toxicity and uncertainty regarding survival benefits of interferon have qualified its acceptance, despite significant durable relapse prevention in a fraction of patients. Predictive biomarkers that would enable selection of patients for therapy would have a large impact upon clinical practice. Specific CTLA-4 polymorphisms have previously shown an association with response to CTLA-4 blockade in patients with metastatic melanoma and the development of autoimmunity.</p> <p>Experimental design</p> <p>286 melanoma patients and 288 healthy controls were genotyped for six CTLA-4 polymorphisms previously suggested to be important (AG 49, CT 318, CT 60, JO 27, JO30 and JO 31). Specific allele frequencies were compared between the healthy and patient populations, as well as presence or absence of these in relation to recurrence. Alleles related to autoimmune disease were also investigated.</p> <p>Results</p> <p>No significant differences were found between the distributions of CTLA-4 polymorphisms in the melanoma population compared with healthy controls. Relapse free survival (RFS) and overall survival (OS) did not differ significantly between patients with the alleles represented by these polymorphisms. No correlation between autoimmunity and specific alleles was shown. The six polymorphisms evaluated where strongly associated (Fisher's exact p-values < 0.001 for all associations) and significant linkage disequilibrium among these was indicated.</p> <p>Conclusion</p> <p>No polymorphisms of CTLA-4 defined by the SNPs studied were correlated with improved RFS, OS, or autoimmunity in this high-risk group of melanoma patients.</p

Evaluation of DNA ploidy in relation with established prognostic factors in patients with locally advanced (unresectable) or metastatic pancreatic adenocarcinoma: a retrospective analysis

<p>Abstract</p> <p>Background</p> <p>Most patients with ductal pancreatic adenocarcinoma are diagnosed with locally advanced (unresectable) or metastatic disease. The aim of this study was to evaluate the prognostic significance of DNA ploidy in relation with established clinical and laboratory variables in such patients.</p> <p>Methods</p> <p>Two hundred and twenty six patients were studied retrospectively. Twenty two potential prognostic variables (demographics, clinical parameters, biochemical markers, treatment modality) were examined.</p> <p>Results</p> <p>Mean survival time was 38.41 weeks (95% c.i.: 33.17–43.65), median survival 27.00 weeks (95% c.i.: 23.18–30.82). On multivariate analysis, 10 factors had an independent effect on survival: performance status, local extension of tumor, distant metastases, ploidy score, anemia under epoetin therapy, weight loss, pain, steatorrhoea, CEA, and palliative surgery and chemotherapy. Patients managed with palliative surgery and chemotherapy had 6.7 times lower probability of death in comparison with patients without any treatment. Patients with ploidy score > 3.6 had 5.0 times higher probability of death in comparison with patients with ploidy score < 2.2 and these with ploidy score 2.2–3.6 had 6.3 times higher probability of death in comparison with patients with ploidy score < 2.2.</p> <p>Conclusion</p> <p>According to the significance of the examined factor, survival was improved mainly by the combination of surgery and chemotherapy, and the presence of low DNA ploidy score.</p

DNA microarray analysis in different human cell lines after virus induction

Technology and information technology have invaded the medical science and the field of research with the technology of DNA microarrays. With the new technology the relative levels of expression of all genes of an organism can be calculated, DNA regions that interact with other DNA regions or specific proteins can be characterized. All these interaction contribute for the survival of the cell and the harmonious cooperation of the cell with neighbor cells or tissues. The regulatory mechanisms that exist interact with each other depending on the state of the cell or the stimulus and then activate new mechanisms or alternative mechanisms – pathways, in response of the different stimulus and information that the cell receives each time from the intracellular or extra-cellular environment. Two cell lines were compared with the use of DNA microarrays in order to identify genes that play a regulatory part in both cell lines and genes that are expressed in a tissue-specific manner. The use of HeLa epithelial and Namalwa B-cells with the combined effect of Sendai virus was the first step for the characterization and recognition of the reprogramming phenomenon in this study. From the analysis less genes were significantly differentially expressed in Namalwa cells after Sendai virus infection but with higher levels of gene expression. Consequently the effect of virus causes more direct and greater response in B cells, fact that is revealed from the big differences in the levels of gene expression in the two cell lines. This differences in the number of genes and in the levels of expression is likely to be caused due to the different histone acetylation and methylation or to the architecture of chromatin, or to the different distribution of the nucleosome on the promoter region of the same gene in the two cell lines and the presence of histone isoforms. Experiments in the lab have shown that the differential distribution of macroH2A on the chromatin in HeLa and Namalwa cells contributes to the differential gene expression that takes part after virus infection. Microarray technology revealed that virus infection reprograms the host genome in HeLa and Namalwa. Different cluster of genes and in various expression levels were activated in order to confront the viral invasion. Key role in this differential reprogramming plays the cell specific distribution of macroH2A on the promoter regions of the genes. From microarray experiments that were carried out in the lab concerning the mechanisms of deposition of macroH2A1 on the genome of HeLa and Namalwa cells, a more strict deposition was located in Namalwa cells. A greater number of genes were found to be affected from the decrease in macroH2A levels in the B-cells. On the contrary increase in macroH2A levels seemed to effect the gene expression levels of HeLa cells, suggesting that macroH2A does not follow the same strict rules as in Namalwa cells and that the deposition of the protein can occur more often with a more relaxed way, thus affecting the gene expression. .........................................................................................Η τεχνολογία και η πληροφορική στον τομέα των ιατρικών επιστημών και στον χώρο της έρευνας έχει εισβάλλει και με την τεχνολογία των μικροσυστοιχιών DNA μέσω των οποίων μπορούν να υπολογιστούν τα σχετικά επίπεδα της έκφρασης όλων των γονιδίων ενός οργανισμού, να ταυτοποιηθούν περιοχές DNA που αλληλεπιδρούν είτε μεταξύ τους, είτε με διάφορες πρωτεΐνες με στόχο την επιβίωση, την εύρυθμη λειτουργία του κυττάρου και την αρμονική συνεργασία του με γειτονικά κύτταρα και ιστούς. Οι ρυθμιστικοί μηχανισμοί που υπάρχουν προκειμένου να πραγματοποιηθούν όλες αυτές οι διαδικασίες αλληλεπιδρούν μεταξύ τους και ανάλογα με την περίσταση ή το ερέθισμα που δέχονται τα κύτταρα ενεργοποιούν συγκεκριμένους μηχανισμούς ή θέτουν σε εφαρμογή εναλλακτικούς μηχανισμούς ή μονοπάτια, σε απόκριση του διαφορετικού ερεθίσματος και πληροφορίας που δέχονται κάθε φορά από τον εξωκυττάριο ή ενδοκυττάριο χώρο. Συγκρίθηκαν δύο διαφορετικές κυτταρικές σειρές προκειμένου να εντοπιστούν, με την τεχνολογία των μικροσυστοιχιών DNA, γονίδια τα οποία παίζουν ρυθμιστικό ρόλο και στους δύο κυτταρικούς τύπους, αλλά και γονίδια των οποίων η έκφραση είναι ιστο-ειδική. Η χρήση των HeLa επιθηλιακών και Namalwa Β-κυττάρων σε συνδυασμό με την επαγωγή τους από Sendai ιό ως εξωκυτταρικό ερέθισμα αποτέλεσε το πρώτο βήμα στον χαρακτηρισμό και ταυτοποίηση του γονιδιακού προφίλ των δύο αυτών κυτταρικών τύπων. Από την ανάλυση παρατηρήθηκε ότι λιγότερα γονίδια επάγονται στα Namalwa κύτταρα τα οποία είνουν να έχουν μεγαλύτερα επίπεδα έκφρασης. Συνεπώς η επίδραση του ιού προκαλεί πιο άμεση και σε μεγαλύτερο βαθμό απόκριση στα Β- κύτταρα, γεγονός που γίνεται αντιληπτό από τις μεγάλες διαφορές στον λόγο έκφρασης των γονιδίων στις δύο κυτταρικές σειρές. Οι διαφορές αυτές στον αριθμό των γονιδίων και στα επίπεδα έκφρασης είναι πιθανόν να οφείλονται σε διαφορετική ακετυλίωση και μεθυλίωση των ιστονών, στην αρχιτεκτονική της χρωματίνης, στην ακριβή θέση του νουκλεοσώματος στον υποκινητή του ίδιου γονιδίου στις δύο κυτταρικές σειρές και παρουσία ισομορφών ιστονών σε αυτό. Από πειράματα στο εργαστήριο έχει βρεθεί ότι η διαφορετική κατανομή της macroH2A στη χρωματίνη των HeLa και Namalwa κυττάρων επαναπρογραμματίζει το γονιδίωμα των κυττάρων προκειμένου να αντιμετωπίσουν την ιϊκή μόλυνση. Συμπεραίνουμε ότι η μόλυνση ανθρώπινων κυτταρικών σειρών με ιό φαίνεται να επαναπρογραμματίζει το γονιδίωμα του ξενιστή και να οδηγεί σε αλλαγή έκφρασης των γονιδίων στις κυτταρικές σειρές HeLa και Namalwa. Ακόμη αποδεικνύεται ότι διαφορετικοί τύποι κυττάρων ενεργοποιούν διαφορετικές ομάδες γονιδίων σε διαφορετικό βαθμό (επίπεδα έκφρασης) προκειμένου να αντιμετωπίσουν την ιϊκή μόλυνση. ...........................................................................................................................

Perturbation of transcriptome in non-neoplastic salivary gland epithelial cell lines derived from patients with primary Sjögren's syndrome

The data presented here are related to the research article titled “Impaired anti-inflammatory activity of PPARγ in the salivary epithelia of Sjögren's syndrome patients imposed by intrinsic NF-κB activation” (Vakrakou et al., Journal of Autoimmunity, in press, 2017). In the cited manuscript, using comparative analyses of salivary gland biopsy specimens and ductal salivary gland epithelial cell (SGEC) lines from SS patients and disease controls, we have demonstrated that the ductal epithelia of SS patients display constitutively reduced PPARγ expression, transcriptional activity and anti-inflammatory function that were associated with cell-autonomously activated NF-κB and IL-1β pathways in these cells. Herein, the comparative transcriptome analysis of SGEC lines is presented. We show that the ductal epithelia of SS patients with severe lymphoepithelial lesions manifest constitutive perturbation in various inflammation- and metabolism related signaling pathways

Enhanced optical forces in plasmonic microstructures

Micromanipulation of dielectric objects, from polystyrene spheres to living cells, is achieved when radiation pressure forces create stable trapping by highly focused laser beams through microscopes. However, the impressive history of optical trapping is shadowed by the light diffraction limit, as research currently has focused on materials below the micron scale, requiring stronger optical confinement and higher intensities than can be provided by the conventional optical tweezers. Recently, plasmonic nanostructures have entered the field, either to assist or enhance it. In this study, we present experimental results on using localized fields of metallic structures for efficient trapping, with various patterns (dots, fringes and squares). The patterns were produced by laser interferometry on almost continuous Ag or Au films on glass and glass covered by an amorphous Al2O3 layer (10 nm thick) respectively. We have calculated the optical forces by measuring the particle’s escape velocity. The results show that the effective quality factor Q in the patterned metal film is enhanced by a factor >10, with respect to the unpatterned metal film and a factor >100, with respect to an uncoated glass. In addition, mathematical simulation of plasmonic fields is investigated to confirm and explain theoretically, the experimentally observed plasmonic enhancement.RP acknowledges a grant from the JAE-doc program co-funded by European Social Fund. This work has partially been supported by MAT2011-28345-C02-02 (Spain) projects

Enhanced optical forces in plasmonic microstructures

Resumen del trabajo presentado en el International Multidisciplinary Microscopy Congress (INTERM2013), celebrado en Antalya (Turquía), del 10 al 13 de octubre de 2013Micromanipulation of dielectric objects, from polystyrene spheres to living cells, is achieved when radiation pressure forces create stable trapping by highly focused laser beams through microscopes. However, the impressive history of optical trapping is shadowed by the light diffraction limit, as research currently has focused on materials below the micron scale, requiring stronger optical confinement and higher intensities than can be provided by the conventional optical tweezers. Recently, plasmonic nanostructures have entered the field, either to assist or enhance it. In this study, we present experimental results on using localized fields of metallic structures for efficient trapping, with various patterns (dots, fringes and squares). The patterns were produced by laser interferometry on almost continuous Ag or Au films on glass and glass covered by an amorphous Al2O3 layer (10 nm thick) respectively. We have calculated the optical forces by measuring the particle’s escape velocity. The results show that the effective quality factor Q in the patterned metal film is enhanced by a factor >10, with respect to the unpatterned metal film and a factor >100, with respect to an uncoated glass. In addition, mathematical simulation of plasmonic fields is investigated to confirm and explain theoretically, the experimentally observed plasmonic enhancement.RP acknowledges a grant from the JAE-doc program co-funded by European Social Fund. This work has partially been supported by MAT2011-28345-C02-02 (Spain) projects

Transcriptomics in tissue glucocorticoid sensitivity

Background Synthetic glucocorticoids are widely used in the treatment of several inflammatory, autoimmune and lymphoproliferative disorders. However, considerable variation in response to therapeutic doses of glucocorticoids has been documented among individuals. The aim of our study was to identify novel glucocorticoid sensitivity-determining genes using genome-wide expression profiling in healthy subjects. Methods One hundred one healthy subjects [mean age +/- standard error of the mean (SEM); 26.52 +/- 0.50 years] were given 0.25 mg dexamethasone at midnight, and serum cortisol concentrations were determined at 08:00 hours the following morning. Subjects were stratified into the 10% most glucocorticoid-sensitive and 10% most glucocorticoid-resistant according to the serum cortisol concentrations. Genomic DNA, RNA and plasma samples were obtained in the 22 subjects one month later. Results Transcriptomic analysis showed variability between glucocorticoid-resistant and glucocorticoid-sensitive subjects. One hundred thirty-three genes were upregulated and 49 downregulated in the glucocorticoid-resistant compared to the glucocorticoid-sensitive group. Further analysis revealed differences between 3 glucocorticoid-resistant and 3 glucocorticoid-sensitive subjects. The majority of the 1058 upregulated genes and 1139 downregulated genes were found to participate in telomere maintenance, systemic lupus erythematosus and Alzheimer’s disease. Interestingly, Synuclein A, a key molecule in Parkinson’s disease, was upregulated in the subgroup of glucocorticoid-sensitive subjects. Conclusions We have identified differences in tissue sensitivity to glucocorticoids among healthy subjects at the transcriptomic level. These differences are associated with differential expression of genes related to autoimmune and neurological disorders