Humans develop gingivitis and periodontitis in response to the challenges produced by microbial dental plaque. Individuals vary in their susceptibility to both gingivitis (superficial inflammation) and periodontitis (extensive inflammation causing bone and tooth loss). The etiology of periodontal disease is not fully understood;however, it is accepted that variance in the human host response to microbial plaque will relate to the host's innate, inflammatory or immune defense systems. Single nucleotide polymorphisms (SNPs) exist in the human genes encoding many molecules pertinent to the host-microbe interaction. Periodontal inflammation (gingivitis and periodontitis) begins with the perturbation of the epithelial cells by bacteria via receptors, including Toll-like Receptors (TLRs). Our preliminary data indicates that the pro-inflammatory cytokines and chemokines produced in response to bacterial and cytokine perturbations differ between individuals and these differences may relate to carriage of a specific TLR4 polymorphism. Our general hypothesis is that individual response characteristics of gingival epithelial cells to foreign challenges, relate to their cellular TLR genotype which influences susceptibility to gingivitis and periodontitis. Thus we will address the following aims utilizing multiple primary human gingival epithelial cells (HGECs), clinical studies and genotype and phenotype analyses.
The first aim i s to characterize molecularly the inter-patient differences in TLR expression in HGECs using qPCR, gene expression profiling, protein assays and immunoreactivity and to correlate this to the TLR genotype. Secondly, functional analysis of genetically- modified HGECs (using siRNA knock-downs and over-expression) will elucidate the role of TLR4 and the Asp299Gly and other SNPs in epithelial LPS hypo-responsiveness. Thirdly, we aim to translate this work by determining clinically if TLR4 polymorphisms and hypo-responsiveness correlate with the severity of experimental gingivitis and if they can differentiate periodontitis cases and controls. Finally, we aim to challenge HGECs and other cell types, monocytes, gut epithelia and endothelial cells to assess LPS responsiveness relevant to the etiopathology of TLR4 associated diseases such as inflammatory bowel disease, atheroma and asthma. Characterization of response differences and determination of related SNPs may lead to new therapeutics or diagnostics in a range of infectious and inflammatory diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Research Project (R01)
Project #
5R01DE017384-05
Application #
7828124
Study Section
Oral, Dental and Craniofacial Sciences Study Section (ODCS)
Program Officer
Lunsford, Dwayne
Project Start
2007-07-09
Project End
2012-05-31
Budget Start
2010-06-01
Budget End
2011-05-31
Support Year
5
Fiscal Year
2010
Total Cost
$352,296
Indirect Cost
Name
University of Pennsylvania
Department
Pathology
Type
Schools of Dentistry
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Kinane, D F; Zhang, P; Benakanakere, M et al. (2015) Experimental gingivitis, bacteremia and systemic biomarkers: a randomized clinical trial. J Periodontal Res 50:864-9
Benakanakere, M; Abdolhosseini, M; Hosur, K et al. (2015) TLR2 promoter hypermethylation creates innate immune dysbiosis. J Dent Res 94:183-91
Bondy-Carey, J L; Galicia, J; Bagaitkar, J et al. (2013) Neutrophils alter epithelial response to Porphyromonas gingivalis in a gingival crevice model. Mol Oral Microbiol 28:102-13
Kinane, James A; Benakanakere, Manjunatha R; Zhao, Jiawei et al. (2012) Porphyromonas gingivalis influences actin degradation within epithelial cells during invasion and apoptosis. Cell Microbiol 14:1085-96
Benakanakere, Manju; Kinane, Denis F (2012) Innate cellular responses to the periodontal biofilm. Front Oral Biol 15:41-55
Buduneli, Nurcan; Kinane, Denis F (2011) Host-derived diagnostic markers related to soft tissue destruction and bone degradation in periodontitis. J Clin Periodontol 38 Suppl 11:85-105
Stathopoulou, Panagiota G; Benakanakere, Manjunatha R; Galicia, Johnah C et al. (2010) Epithelial cell pro-inflammatory cytokine response differs across dental plaque bacterial species. J Clin Periodontol 37:24-9
Benakanakere, Manjunatha R; Zhao, Jiawei; Galicia, Johnah C et al. (2010) Sphingosine kinase-1 is required for toll mediated beta-defensin 2 induction in human oral keratinocytes. PLoS One 5:e11512
Zhao, Jiawei; Benakanakere, Manjunatha R; Hosur, Kavita B et al. (2010) Mammalian target of rapamycin (mTOR) regulates TLR3 induced cytokines in human oral keratinocytes. Mol Immunol 48:294-304
Galicia, Johnah C; Benakanakere, Manjunatha R; Stathopoulou, Panagiota G et al. (2009) Neutrophils rescue gingival epithelial cells from bacterial-induced apoptosis. J Leukoc Biol 86:181-6

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