CD14‐Mediated Induction of Interleukin‐8 and Monocyte Chemoattractant Protein‐1 by a Heat‐Resistant Constituent of Porphyromonas gingivalis in Endothelial Cells

Abstract

Viable and inactivated Porphyromonas gingivalis dose-dependently induced interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) secretion in human umbilical vein endothelial cells (HUVECs). The inactivated P. gingivalis, in comparison with viable bacteria, tended to enhance the production of both chemokines more strongly. The production of MCP-1 protein began increasing immediately after stimulation by P. gingivalis, and there was a nearly linear increase from 0 to 8 h of incubation, whereas IL-8 production showed a linear increase between 4 and 12 h of incubation. The IL-8 and MCP-1 mRNA expressions in HUVECs as determined by reverse transcriptase-polymerase chain reaction (RT-PCR) or Quantikine mRNA colorimetric quantification kits were found to be enhanced by P. gingivalis. Furthermore, the time courses of IL-8 and MCP-1 mRNA expressions were in accordance with those of protein production. Addition of polymyxin B or boiling did not weaken the stimulatory effect of P. gingivalis, which inhibited the effect of Escherichia coli lipopolysaccharide (E. coli LPS) and tumour necrosis factor-a (TNF-a), respectively. In contrast, the induction of IL-8 and MCP-1 by P. gingivalis was significantly reduced by anti-CD14 antibody. Our results suggest that some heatstable component of P. gingivalis, including LPS, may be responsible for the induction of IL-8 and MCP-1 in HUVECs by a CD14-dependent mechanism. These effects might be involved in the accumulation and activation of neutrophils and monocytes at an early stage of the periodontal pathogenesis.

Endotoxin Contamination in Commercially Available Pokeweed Mitogen Contributes to the Activation of Murine Macrophages and Human Dendritic Cell Maturation

“…LPS is a heat-stable molecule, whereas proteins are susceptible to heat treatment, leading to denaturation (6,20,21). To test the possibility that proteinaceous components in the PWM preparation induced TLR4 activation, we boiled PWM for 10 min prior to stimulation of CHO/CD14/TLR4.…”

How has research into cytokine interactions and their role in driving immune responses impacted our understanding of periodontitis?

“…Human endothelial cells were also shown to respond to P. gingivalis by stimulating OPG via an NF‐ κ B‐dependent pathway, and thus could act as a source of OPG in periodontitis (Kobayashi‐Sakamoto et al 2004). Human umbilical vein endothelial cells produced the chemokines IL‐8 and MCP‐1 in response to stimulation with P. gingivalis , suggesting that endothelial cells might be involved in the accumulation and activation of neutrophils and monocytes at an early stage in periodontal pathogenesis (Mao et al 2002).…”

Oral Streptococci and Cardiovascular Disease: Searching for the Platelet Aggregation‐Associated Protein Gene and Mechanisms of Streptococcus sanguis‐Induced Thrombosis

“…During bacteremias originating from the oral tissues and dental plaque, the polymicrobial insult would also introduce lipopolysaccharide (LPS)-expressing bacteria to the blood. LPS will also induce expression of tissue factor by monocytes 23 and endothelial cells in vitro 24,25 and in vivo 26 (Fig. 1).…”