Epigenetic dynamics of Helicobacter pylori-induced COX-2 activation

Peluso, Silvia (2009) Epigenetic dynamics of Helicobacter pylori-induced COX-2 activation. [Tesi di dottorato] (Inedito)

Full text disponibile come:

[img]
Preview
PDF - Richiede un editor Pdf del tipo GSview, Xpdf o Adobe Acrobat Reader
2329Kb

Abstract

Background and Aims: Cyclooxigenase (COX)-2 is over expressed in gastrointestinal neoplasia and Helicobacter pylori (H. pylori) infection is casually linked to gastric cancer. We undertook this study to investigate the mechanism mediating H. pylori-induced COX-2 expression in human gastric epithelial cell line MKN28. Methods: MKN28 cells were infected with wild-type H. pylori 60190 strain for different time points, and the levels of COX-2 messenger RNA (mRNA) and protein expression were evaluated using real-time polymerase chain reaction (PCR) and Western blotting, respectively. Chromatin immunoprecipitation assays were performed to evaluate the level of histone modifications and the recruitment of histone deacetylases (HDACs) 1, and 2, nuclear transcription factor (NF-κB) and RNA polymerse II (PolII) to the COX-2 promoter. The technique of MALDI-TOF MS was used to determine the methylation analysis of CpG islands of the COX-2 promoter. Results: H. pylori induced a time-dependent increase of mRNA and protein expression of COX-2 in MKN28 cells. Furthermore, H. pylori-infected gastric epithelial cells showed dynamic changes of methylation and acetylation pattern of histone H3 at the promoter of COX-2 gene. Preventing histone deacetylation by the histone deacetylase inhibitor trichostatin A (TSA) augumented the H. pylori-induced COX-2 response. After exposure to H. pylori, we found a decreased in global histone deacetylase expression and activity. The hyperacetylation of histone H3 correlate with the release of HDAC 1, which first decreased and later reappeared at the COX-2 promoter. Moroever after H. pylori infection, NF-κB and RNA polymerase II were time-dependently recruited to the COX-2 promoter. In addition we show a dynamic changes in the methylaion status of promoter CpGs. Conclusions: These results show for the first time that H. pylori-induced activation of COX-2 gene transcription was caused by interference with epigenetic mechanisms regulating COX-2 gene accessibility. These patways may contribute to the host response in H. pylori-associated gastric inflammation and carcinogenesis.

Tipologia di documento:Tesi di dottorato
Parole chiave:epigenetic, Helicobacter pylori, COX-2
Settori scientifico-disciplinari MIUR:Area 06 Scienze mediche > MED/07 MICROBIOLOGIA E MICROBIOLOGIA CLINICA
Area 06 Scienze mediche > MED/04 PATOLOGIA GENERALE
Coordinatori della Scuola di dottorato:
Coordinatore del Corso di dottoratoe-mail (se nota)
Di Lauro, Robertodilauro@szn.it
Tutor della Scuola di dottorato:
Tutor del Corso di dottoratoe-mail (se nota)
Chiariotti, Lorenzochiariot@unina.it
Stato del full text:Accessibile
Data:2009
Numero di pagine:104
Istituzione:Università degli Studi di Napoli Federico II
Dipartimento o Struttura:Biologia e Patologia Cellulare e Molecolare "Luigi Califano"
Tipo di tesi:Dottorato
Stato dell'Eprint:Inedito
Scuola di dottorato:Medicina Molecolare
Denominazione del dottorato:Genetica e Medicina Molecolare
Ciclo di dottorato:XXII
Numero di sistema:3820
Depositato il:19 Maggio 2010 15:36
Ultima modifica:28 Giugno 2012 12:33

Solo per gli Amministratori dell'archivio: edita il record