title: NLRP3 inflammasome is required for apoptosis of Aggregatibacter actinomycetemcomitans-infected human osteoblastic MG63 cells.
abstract: Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) is a Gram-negative bacterium which is implicated in the pathogenesis of human periodontal disease and in particular aggressive periodontitis. Virulence factors from A. actinomycetemcomitans have been shown to induce apoptosis of osteoblasts, however, the underlying mechanisms of the induction of apoptosis are poorly understood. In the present study, the infection of A. actinomycetemcomitans in human osteoblastic MG63 cells was established. Accordingly, A. actinomycetemcomitans infection enhanced significant apoptosis of MG63 cells. We found that both expression levels of NLRP3 and ASC were increased dramatically after MG63 cell cultures exposed to A. actinomycetemcomitans. Moreover, the secretion of mature interleukin-1β (IL-1β) and IL-18 were extensively induced in A. actinomycetemcomitans-infected cells as compared with non-invasion group of MG63 cell cultures, indicating the activation of the NLRP3 inflammasome during infection. Finally, we found that the knockdown expression of NLRP3 by specific small interfering RNA (siRNA) attenuated apoptosis of A. actinomycetemcomitans-infected MG63 cells. Our data suggest that A. actinomycetemcomitans promotes apoptosis of human osteoblasts at least partially through the NLRP3 inflammasome.
authors.affiliation: Department of Pediatric Dentistry, School of Stomatology, China Medical University, Shenyang 110001, People's Republic of China.
authors.forename: Panyu
authors.initials: P
authors.lastname: Zhao
authors.affiliation: Department of Oral Biology and Periodontics, School of Stomatology, China Medical University, Shenyang 110001, People's Republic of China.
authors.forename: Junchao
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Oral Biology and Periodontics, School of Stomatology, China Medical University, Shenyang 110001, People's Republic of China.
authors.forename: Chunling
authors.initials: C
authors.lastname: Pan
authors.affiliation: Department of Oral Biology and Periodontics, School of Stomatology, China Medical University, Shenyang 110001, People's Republic of China. Electronic address: cmupanyaping@163.com.
authors.forename: Yaping
authors.initials: Y
authors.lastname: Pan
mesh_terms: D016976:Aggregatibacter actinomycetemcomitans; D017209:Apoptosis; D002352:Carrier Proteins / Q000502:physiology*; D002460:Cell Line; D006801:Humans; D058847:Inflammasomes / Q000502:physiology*; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D010006:Osteoblasts / Q000382:microbiology / Q000502:physiology*; D016871:Pasteurellaceae Infections / Q000276:immunology / Q000473:pathology
chemical_list: D002352:Carrier Proteins; D058847:Inflammasomes; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C453881:NLRP3 protein, human
keywords: Aggregatibacter actinomycetemcomitans; Apoptosis; Inflammasome; NLRP3; Osteoblasts