Tumor necrosis factor‐α and interleukin‐1β expression pathway induced by Streptococcus mutans in macrophage cell line RAW 264.7

Abstract

Streptococcus mutans, a major etiological agent of dental caries, frequently causes systemic disease, such as subacute bacterial endocarditis, if it enters the bloodstream. In this study, the production pathways of the proinflammatory cytokines, tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), induced by S. mutans in mouse macrophage were examined using a quantitative real-time polymerase chain reaction and an enzyme-linked immunosorbent assay. The S. mutans stimulated the expression of TNF-α and IL-1β mRNA at a multiplicity of infection of 1 : 100, which increased at 2 and 4 h, respectively, to 24 h. It also induced the production of high levels of the TNF-α and IL-1β proteins, which increased at 2 h and reached a peak at 4 and 24 h, respectively. Nuclear factor-κB (NF-κB) was activated and reached a maximum level 30 min after the S. mutans treatment. The expression of TNF-α and IL-1β mRNA and protein was suppressed by the treatment with pyrrolidine dithiocarbamate, an NF-κB inhibitor. The S. mutans-induced TNF-α expression was suppressed by the presence of SB203580, a p38 mitogen-activated protein (MAP) kinase inhibitor, or SP600125, a Jun N-terminal kinase (JNK) MAP kinase inhibitor. On the other hand, IL-1β expression was inhibited by extracellular signal-regulated kinase (ERK)/p38/JNK MAP kinase inhibitor pretreatment. In addition, TNF-α production was suppressed more in the Toll-like receptor 2(-/-) (TLR2(-/-)) macrophages than in the TLR4(-/-) macrophages, whereas IL-1β production was suppressed more in the TLR4(-/-) macrophages than in the TLR2(-/-) macrophages. These results show that S. mutans stimulates the production of TNF-α and IL-1β in the mouse macrophage cell line, RAW 264.7, by activating ERK/p38/JNK, and NF-κB through TLR2 and TLR4, respectively.

Prophylactic effect of human lactoferrin against Streptococcus mutans bacteremia in lactoferrin knockout mice

“…It has been reported that TNF-α, IL-1β and keratinocyte chemoattractant (a functional homologue of human IL-8) cytokines are the distinctive biomarkers for fatal bacteremic conditions [33]. It has also been reported that S. mutans is capable of inducing TNF-α and IL-1β pathways [37]. The LFKO −/− mice with hLF supplementation decreased the expression of such cytokines suggestive of immunomodulatory role of LF.…”

Mitochondrial ROS induced by chronic ethanol exposure promote hyper-activation of the NLRP3 inflammasome

“…Unlike many innate immune pathways, stimulation of a functional inflammasome requires two events, priming and activation. During priming (step 1), activation of the transcription factor NF-κB downstream of the stimulation of many PRRs, facilitates the transcription and translation of many inflammasome components (as well as the secretion of pro-inflammatory cytokines such as TNF and IL-6) [31]. Activation of the inflammasome complex (step 2) requires the exposure of cells to a separate set of PAMPs and DAMPs, which work through unique signaling pathways to induce the oligomerization of one of several different Nucleotide Oligomerization Domain (NOD)-Like Receptor (NLR) proteins, the adaptor protein Apoptosis-associated Speck-like protein containing a CARD (ASC), and pro-caspase-1, into an organized inflammasome complex [32].…”

Ethanol and Other Short-Chain Alcohols Inhibit NLRP3 Inflammasome Activation through Protein Tyrosine Phosphatase Stimulation

“…Unlike many innate immune pathways, stimulation of a functional inflammasome requires two steps. During priming (step 1), activation of the transcription factor NF-κB, downstream of the stimulation of many PRRs, leads to the production of several components of the inflammasome and the secretion of the pro-inflammatory cytokine TNF (2). Activation of the inflammasome (step 2) requires the exposure of cells to a separate set of PAMPs and DAMPs, which work through unique signaling pathways leading to the oligomerization of one of several different Nucleotide Oligomerization Domain (NOD)-Like Receptor (NLR) proteins, the adaptor protein Apoptosis-associated Speck-like protein containing a CARD (ASC), and pro-caspase-1 into an organized inflammasome complex (3).…”