Identification of differentially expressed genes in human alveolar bone cells cultured on different titanium surfaces

Author(s)

Maidy Rehder Wimmers Ferreira

• Document type: Doctoral Thesis
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Odontologia de Ribeirão Preto (PCARP/BC)
• Defense date: 2014-11-19

Examining board members

Karina Fittipaldi Bombonato Prado; Ana Paula de Souza Faloni; Daniela Micheline dos Santos; Selma Siessere

• Advisor: Karina Fittipaldi Bombonato Prado

Abstract

Titanium implants have been extensively used in orthopedics and dentistry, mainly as a replacement for missing teeth. Titanium is the metal implant of choice due to its high biocompatibility and corrosion resistance, as well as absence of immune response, while promoting osseointegration. The biocompatibility of the material depends on cellular response in contact with the surface; therefore, changes on this surface can have beneficial impacts on osseointegration through changes in interactions with cells at the implant site, such as osteoblastic cells. The objective of this study was to characterize the cellular response of osteoblastic cells from human alveolar crest in contact with different titanium surfaces: control (polished), nanotextured, nano+submicrotextured and rough microtexture. The performed biochemical assays included cell proliferation and viability, total protein content and alkaline phosphatase activity, in addition to the detection and quantification of mineralized nodules, using the non-parametric statistical tests of Kruskal-Wallis and Mann-Whitney (p≤0,05). Osteoblastic gene modulation was evaluated by means of an oligo microarray method using Agilent format 4 x 44 K slides and Agilent 8x15 K slides for microRNAs analysis. In order to identify changes in gene expression, it was used the GeneSpring GX program. Gene expression was validated by quantitative PCR real time (qRT-PCR). It was observed a peak in cell culture proliferation at 10 days and a gradual increase in cell viability over the periods. Among the treated surfaces, we observed an increase in the amount of total protein in nanotextured when compared to nano+submicrotextured at 10 days of culture (p≤0,05), and a progressive increase of alkaline phosphatase activity, with higher activity in nanotextured compared to nano+submicrotextured at 14 days of culture (p≤0,05). There was no qualitative difference among the groups with regards to mineralized nodules, although the rough microtexture group showed higher amounts of calcium than the nanotextured group (p≤0,05). Our results showed a differential expression of 716 mRNAs (fold change≥2,0 and p≤0,05) and 32 microRNAs (fold change≥1,5 and p≤0,01), with functions associated to the osteogenesis process, mainly mineralization, cell adhesion, apoptosis, cell proliferation and differentiation. The results suggest that, with the protocols used in this investigation, the treatments performed in the titanium surface induce changes in the metabolism of osteoblastic cells, both at the cellular as well as at the gene expression levels (AU)

• FAPESP's process: 11/14046-7 - Identification of differentially expressed genes in human alveolar bone cells cultured on different titanium surfaces
• Grantee: Maidy Rehder Wimmers Ferreira
• Support Opportunities: Scholarships in Brazil - Doctorate