Effects of Endotoxin Tolerance Induced by Porphyromonas gingivalis Lipopolysaccharide on Inflammatory Responses in Neutrophils

AbstractPeriodontitis is a dental plaque –induced chronic inflammatory disease. Long-term exposure of the host to periodontal pathogens leads to a hyporesponsive state to the following stimulations, which is described as endotoxin tolerance. Neutrophils are the most abundant innate immune cells in the body. To clarify the roles of endoto xin tolerance in periodontitis, inflammatory responses inPorphyromonas gingivalis (P. gingivalis) lipopolysaccharide (LPS) –tolerized neutrophils were explored in this study. Here, apoptosis and respiratory burst in neutrophils upon single or repeatedP. gingivalis LPS stimulations were explored by flow cytometry. Cytokine production (TNF- α, IL-8, and IL-10) in tolerized neutrophils or neutrophils co-cultured with peripheral blood mononuclear cells was determined by ELISA. Phagocytosis ofP. gingivalis by tolerized neutrophils was also assayed by flow cytometry. In addition, quality and quantitation of neutrophil extracellular trap (NET) formation were detected using immunofluorescence microscope and microplate reader, respectively. The protein expressions of extracellular signal –regulated kinase1/2 (ERK1/2), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (p38 MAPK) were examined to identify possible mechanisms for the abovementioned changes. Tolerance induced byP. gingivalis LPS significantly suppressed apoptosis, reactive oxygen species (ROS) generation, and phagocytosis in neutrophils (p <  0.05). In ...
Source: Inflammation - Category: Allergy & Immunology Source Type: research