Porphyromonas gingivalis, a black-pigmented, gram- negative anaerobe, is widely implicated as an important etiological agent of periodontal disease. This bacterium expresses several potential virulence factors (e.g., capsule, LPS, fimbriae, membrane vesicles, and hydrolytic enzymes) that may contribute to its pathogenicity. Another virulence factor, the recA gene, confers resistance to the oxidative stress environment of the inflammatory periodontal pocket. The recA gene product is a key protein in DNA repair that protects P. gingivalis from DNA damage induced by bactericidal reactive oxygen derivatives generated in the periodontal pocket by neutrophils and transient air exposure. Our laboratory has identified two genes, vimA and bcp, that may be part of the recA transcription unit and may also function in virulence. Further, the vimA-mediated virulence modulation in P. gingivalis, may represent a novel posttranscriptional regulation of virulence factors in this organism. Because the BCP homologue may have peroxidase function, and gingipains are involved in heme accumulation which can inactivate H2O2, it might be considered an important strategy for the organism to coordinate its oxidative stress and proteolytic activities. This importance is further supported by observation that the recA locus promoter is active during infection of the murine host. Moreover, the promoter activity is affected by temperature, iron and calcium which are factors known to coordinately regulate the expression of other bacterial virulence genes. Our observations, taken together, may suggest an important role for the complex recA locus in the survival and virulence of P. gingivalis. It is our hypothesis that the bcp-recA-vimA transcriptional unit is important for virulence and protection against oxidative stress. Our overall objective is to elucidate the molecular mechanism(s) for the vimA-mediated virulence regulation and examine the relative importance of the bcp-recA-vimA operon in oxidative stress resistance in P. gingivalis.
Specific aims for the proposed research are: 1) To characterize the bcp-recA-vimA transcriptional unit in P. gingivalis W83. This will include: a) mapping the transcription initiation site; b) verifying the promoter sequence upstream of the primary start site; c) evaluating the effect of the bcp gene on the function on the recA and vimA genes; 2) To examine the functional significance of the vimA mutation on protease activation in P. gingivalis W83; and 3) To evaluate the importance of the bcp-recA-vimA transcriptional unit in oxidative stress protection.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Research Project (R01)
Project #
3R01DE013664-01A2S1
Application #
6587479
Study Section
Special Emphasis Panel (ZRG1 (02))
Program Officer
Mangan, Dennis F
Project Start
2002-04-01
Project End
2006-02-28
Budget Start
2002-04-01
Budget End
2003-02-28
Support Year
1
Fiscal Year
2002
Total Cost
$44,314
Indirect Cost
Name
Loma Linda University
Department
Microbiology/Immun/Virology
Type
Schools of Dentistry
DUNS #
City
Loma Linda
State
CA
Country
United States
Zip Code
92350
Dou, Y; Rutanhira, H; Chen, X et al. (2018) Role of extracytoplasmic function sigma factor PG1660 (RpoE) in the oxidative stress resistance regulatory network of Porphyromonas gingivalis. Mol Oral Microbiol 33:89-104
Holden, Megan S; Black, Jason; Lewis, Ainsely et al. (2016) Antibacterial Activity of Partially Oxidized Ag/Au Nanoparticles against the Oral Pathogen Porphyromonas gingivalis W83. J Nanomater 2016:
Dou, Y; Aruni, W; Muthiah, A et al. (2016) Studies of the extracytoplasmic function sigma factor PG0162 in Porphyromonas gingivalis. Mol Oral Microbiol 31:270-83
Boutrin, M-C; Yu, Y; Wang, C et al. (2016) A putative TetR regulator is involved in nitric oxide stress resistance in Porphyromonas gingivalis. Mol Oral Microbiol 31:340-53
McKenzie, R M E; Aruni, W; Johnson, N A et al. (2015) Metabolome variations in the Porphyromonas gingivalis vimA mutant during hydrogen peroxide-induced oxidative stress. Mol Oral Microbiol 30:111-27
Aruni, A Wilson; Dou, Yuetan; Mishra, Arunima et al. (2015) The Biofilm Community-Rebels with a Cause. Curr Oral Health Rep 2:48-56
Aruni, A Wilson; Mishra, Arunima; Dou, Yuetan et al. (2015) Filifactor alocis--a new emerging periodontal pathogen. Microbes Infect 17:517-30
Dou, Y; Robles, A; Roy, F et al. (2015) The roles of RgpB and Kgp in late onset gingipain activity in the vimA-defective mutant of Porphyromonas gingivalis W83. Mol Oral Microbiol 30:347-60
Aruni, W; Chioma, O; Fletcher, H M (2014) Filifactor alocis: The Newly Discovered Kid on the Block with Special Talents. J Dent Res 93:725-32
Dou, Yuetan; Aruni, Wilson; Luo, Tianlong et al. (2014) Involvement of PG2212 zinc finger protein in the regulation of oxidative stress resistance in Porphyromonas gingivalis W83. J Bacteriol 196:4057-70

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