Analysis of Porphyromonas gingivalis lipopolysaccharide when presente in a bacterial comunity

• Grant number: 13/17928-6
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: February 01, 2014
• End date: October 31, 2014
• Field of knowledge: Health Sciences - Dentistry - Endodontics
• Principal Investigator: Brenda Paula Figueiredo de Almeida Gomes
• Grantee: Ariane Cássia Salustiano Marinho
• Supervisor: Richard P. Darveau
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil
• Institution abroad: University of Washington, United States
• Associated to the scholarship: 13/02402-9 - Microbiological and LPS investigation and their antigenic activity in teeth with pulpal necrosis and irreversible pulpitis in pro-inflammatory cytokine production, BP.DR

Abstract

Lipopolysaccharide (LPS) is a key inflammatory mediator. Due to its ability to potently activate host inflammatory and innate defense responses, it has been proposed to function as an important molecule that alerts the host about the potential bacterial infection. However, although highly conserved, LPS contains important structural differences among different bacterial species that can significantly alter the host responses. For example, LPS obtained from Porphyromonas gingivalis, an etiologic agent for apical periodontitis, causes a highly unusual innate host response, as it engages TLR-2 but not TLR-4 as happens with the other species. It is proposed that, since LPS is a key ligand for the human innate host defense system, the unusual properties of P. gingivalis LPS are associated with the bacterium's role in the pathogenesis of apical periodontitis. The aims of this study are 1) To investigate the presence of the target Gram-negative anaerobic bacteria, P. gingivalis, in samples collected from primarily infected root canal and to correlate its presence with the clinical/radiographic features of the primary endodontic disease; 2) To isolate LPS from P. gingivalis and to evaluate its inflammatory potential in cell culture regarding the production of pro-inflammatory cytokines; 3) To compare the inflammatory response induced by P. gingivalis LPS obtained from root canals and that evoked by the P. gingivalis ATCC 33277 (American Type Culture Collection). Microbial samples will be taken from 10 root canals with pulpal necrosis and apical periodontitis using sterile non-pyrogenic/paper points. Culture and polymerase chain reaction technique (16S rDNA) will be used for bacterial investigation. LPS isolation will be performed by the cold MgCl2-ethanol (EtOH) procedure followed by lipid extraction and conversion to sodium salts. Assay of cytokines production - IL-1 ² and TNF-± - will be analyzed via the enzyme-linked immunosorbent assay (ELISA). All statistical analysis will be performed using a software program (SPSS 19.0, SPSS Inc, Chicago, IL, USA).Key-words: Bacteria, LPS, cytokines, P. gingivalis. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

MARINHO, A. C. S.; TO, T. T.; DARVEAU, R. P.; GOMES, B. P. F. A.. Detection and function of lipopolysaccharide and its purified lipid A after treatment with auxiliary chemical substances and calcium hydroxide dressings used in root canal treatment. International Endodontic Journal, v. 51, n. 10, p. 1118-1129, OCT 2018. (13/02402-9, 15/23479-5, 13/17928-6)

MARINHO, A. C. S.; MARTINHO, F. C.; GONCALVES, L. M.; RABANG, H. R. C.; GOMES, B. P. F. A.. Does the Reciproc file remove root canal bacteria and endotoxins as effectively as multifile rotary systems?. International Endodontic Journal, v. 48, n. 6, p. 542-548, JUN 2015. (13/02402-9, 10/13498-9, 10/17877-4, 13/17928-6, 10/19136-1, 11/09047-4)