title: Role of exopolysaccharide in Aggregatibacter actinomycetemcomitans-induced bone resorption in a rat model for periodontal disease.
abstract: Aggregatibacter actinomycetemcomitans a causative agent of periodontal disease in humans, forms biofilm on biotic and abiotic surfaces. A. actinomycetemcomitans biofilm is heterogeneous in nature and is composed of proteins, extracellular DNA and exopolysaccharide. To explore the role played by the exopolysaccharide in the colonization and disease progression, we employed genetic reduction approach using our rat model of A. actinomycetemcomitans-induced periodontitis. To this end, a genetically modified strain of A. actinomycetemcomitans lacking the pga operon was compared with the wild-type strain in the rat infection model. The parent and mutant strains were primarily evaluated for bone resorption and disease. Our study showed that colonization, bone resorption/disease and antibody response were all elevated in the wild-type fed rats. The bone resorption/disease caused by the pga mutant strain, lacking the exopolysaccharide, was significantly less (P < 0.05) than the bone resorption/disease caused by the wild-type strain. Further analysis of the expression levels of selected virulence genes through RT-PCR showed that the decrease in colonization, bone resorption and antibody titer in the absence of the exopolysaccharide might be due to attenuated levels of colonization genes, flp-1, apiA and aae in the mutant strain. This study demonstrates that the effect exerted by the exopolysaccharide in A. actinomycetemcomitans-induced bone resorption has hitherto not been recognized and underscores the role played by the exopolysaccharide in A. actinomycetemcomitans-induced disease.
authors.affiliation: Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, 07103, United States of America.
authors.forename: Mayilvahanan
authors.initials: M
authors.lastname: Shanmugam
authors.affiliation: Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, 07103, United States of America.
authors.forename: Prerna
authors.initials: P
authors.lastname: Gopal
authors.affiliation: Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, 07103, United States of America.
authors.forename: Faiha
authors.initials: F
authors.lastname: El Abbar
authors.affiliation: Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, 07103, United States of America.
authors.forename: Helen C
authors.initials: HC
authors.lastname: Schreiner
authors.affiliation: Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, 07103, United States of America.
authors.forename: Jeffrey B
authors.initials: JB
authors.lastname: Kaplan
authors.affiliation: Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, 07103, United States of America.
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Fine
authors.affiliation: Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, 07103, United States of America.
authors.forename: Narayanan
authors.initials: N
authors.lastname: Ramasubbu
mesh_terms: D016976:Aggregatibacter actinomycetemcomitans; D000818:Animals; D001862:Bone Resorption / Q000382:microbiology*; D004195:Disease Models, Animal; D008297:Male; D009055:Mouth / Q000382:microbiology*; D016871:Pasteurellaceae Infections / Q000150:complications*; D010510:Periodontal Diseases / Q000382:microbiology*; D011135:Polysaccharides, Bacterial / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D011135:Polysaccharides, Bacterial