Tecnologias moleculares no estudo das doenças periodontais

Author(s)

Tiago Taiete

• Document type: Master's Dissertation
• Press: Piracicaba, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2013-06-03

Examining board members

Marcio Zaffalon Casati; Renato Corrêa Viana Casarin; Fernanda Vieira Ribeiro

• Advisor: Marcio Zaffalon Casati

Abstract

Aggressive periodontitis is characterized by early onset, rapid progression and poor response to treatment compared to chronic periodontitis. However, mechanisms responsible for these differences are not fully understood. Tools such as genomics, proteomics and transcriptomics can clarify these aspects, producing important information about the pathogenesis of periodontal diseases. Therefore, the aims of this study were: i) Provide a literature review focused on the application of genomics, transcriptomics, proteomics, and metabolomics in the study of periodontal diseases. ii) Evaluate the gene expression profile of tissue from masticatory mucosa, without the influence of biofilm, in patients with a history of generalized aggressive and chronic periodontitis, and also with gene expression profile of individuals without periodontitis, with the aim to identify possible constitutive alterations in gene expression, which may be related to the differences between both forms of periodontitis. For the first objective, it was performed a review of articles that employed omics technologies in the study of periodontal diseases. The studies in the literature indicated that these technologies can lead to a better understanding of molecular events involved in the pathogenesis of periodontal diseases. For the second objective, masticatory mucosa tissue samples were obtained from 4 patients with a history of chronic periodontitis, 4 with generalized aggressive periodontitis, and 4 from subjects without history of periodontitis. Tissue samples were processed for total RNA extraction, double-strand cDNA synthesis for subsequent hybridization reaction on microarrays, which assessed the expression of 45033 genes. R and Bioconductor softwares used to perform the RMA analysis (Robust Multi-Array), calculate the value of expression (fold-change) and the p-value for multiple comparisons through Benjamini-Hochberg method. Enrichment analysis, through gene ontology (GO) and pathway analysis, was performed with DAVID (Database for Annotation, Visualization and Integrated Discovery). Three comparisons were performed: comparison 1 (aggressive periodontitis x healthy subjects); comparison 2 (chronic periodontitis x healthy subjects); and comparison 3 (chronic periodontitis x aggressive periodontitis). Comparisons analysis found 192 genes and 50 groups differentially expressed in comparison 1, 43 genes and 27 groups in comparison 2, and 168 genes and 75 groups in comparison 3. Genes with function in the immune system, including natural killer cells receptors, were higher expressed in aggressive periodontitis; in contrast, genes involved in proliferation and differentiation of keratinocytes, as well as genes with function in neural process were lower expressed. Chronic periodontitis subjects were characterized by increased expression of genes related to response to external stimuli, and a decrease in the expression of genes related to the immune system. Within the limits of this study, it can be concluded that there are differences in the gene expression profile of masticatory mucosa of patients with a history of chonic and aggressive periodontitis, when compared among them and with healthy group, which may be associated with differences in their pathogenesis (AU)

• FAPESP's process: 11/03625-6 - Gene expression profile in masticatory mucosa tissue of patients with history of chronic and aggressive periodontitis
• Grantee: Tiago Taiete
• Support Opportunities: Scholarships in Brazil - Master