The activation of pyrin domain-containing-3 inflammasome depends on lipopolysaccharide from Porphyromonas gingivalis and extracellular adenosine triphosphate in cultured oral epithelial cells.
BACKGROUND
Gingival epithelial cells are the major population of the gingival tissue, acting as the front-line defense against microbial intrusion and regulating the homeostasis of the periodontal tissue in health and disease via NLR family pyrin domain-containing-3 (NLRP3) inflammasome, which recognizes pathogen- and danger-associated molecular patterns (PAMPs and DAMPs). The aim of this study was to determine whether the activation of NLRP3 inflammasome depends on infection with the periodontal pathogen Porphyromonas gingivalis (P. gingivalis), or stimulation with P. gingivalis lipopolysaccharide (LPS), and/or extracellular adenosine triphosphate (ATP).


METHODS
An oral epithelial cell line was treated with P. gingivalis, P. gingivalis LPS and ATP. The gene and protein expression of NLRP3 inflammasome components were quantified by real time RT-PCR and immunoblots. Production of IL-1β and IL-18 was measured by ELISA.


RESULTS
There was no increase in NLRP3 inflammasome gene expression after P. gingivalis infection unless pre-stimulated by ATP. Obvious increases of NLRP3 inflammasome gene expression was observed after P. gingivalis LPS stimulation, even pre-stimulated by ATP at 2 h.


CONCLUSIONS
The findings indicate that the activation of NLRP3 inflammasome does not rely on P. gingivalis infection, unless stimulated by P. gingivalis LPS and/or extracellular ATP, suggesting diverse signaling pathways are involved in the host immune response.
Department of Periodontology, Shandong Provincial Key Laboratory of Oral Biomedicine, Shandong University, Jinan, 250012, People's Republic of China. xyd_gw@163.com.|Department of Endodontics, Yantai Stomatological Hospital, Yantai, Shandong Province, China. xyd_gw@163.com.
Wei
W
Guo
Yantai Stomatological Hospital, Yantai, Shandong Province, China. wangpengm@163.com.
Peng
P
Wang
Yantai Stomatological Hospital, Yantai, Shandong Province, China. dentlzh@163.com.
Zhonghao
Z
Liu
Department of Periodontology, Shandong Provincial Key Laboratory of Oral Biomedicine, Shandong University, Jinan, 250012, People's Republic of China. xyd_gw@126.com.
Pishan
P
Yang
Institute of Dental Research, Westmead Millennium Institute and Westmead Centre for Oral Health, Westmead Hospital, Westmead, Australia. p.ye@sydney.edu.au.
Ping
P
Ye
D000255:Adenosine Triphosphate; D002460:Cell Line; D004847:Epithelial Cells; D005881:Gingiva / Q000378:metabolism / Q000382:microbiology; D006801:Humans; D020382:Interleukin-18 / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D008070:Lipopolysaccharides / Q000502:physiology; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein / Q000378:metabolism; D016966:Porphyromonas gingivalis; D000071196:Pyrin Domain; D015398:Signal Transduction
C000589760:IL18 protein, human; D020382:Interleukin-18; D053583:Interleukin-1beta; D008070:Lipopolysaccharides; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C453881:NLRP3 protein, human; D000255:Adenosine Triphosphate