The Role of Lipopolysaccharide Structure in Monocyte Activation and Cytokine Secretion

作者：Rebecca E. Plevin, Megan Knoll, Meghan McKay, Saman Arbabi, Joseph Cuschieri · 发表于：Shock · 年份：2015 · DOI：10.1097/shk.0000000000000470 · 被引用次数：40 · 研究领域：Immune Response and Inflammation、Immune Cell Function and Interaction、Lipid Membrane Structure and Behavior

BACKGROUND: The lipopolysaccharide (LPS) molecule is composed of a hydrophobic lipid region (Lipid A), an oligosaccharide core, and an O-Antigen chain. Lipid A has been described as the molecular region responsible for inducing activation of immune cells. We hypothesize that the O-Antigen plays a critical role in the activation and responsiveness of mononuclear cell immune function. METHODS: Peripheral blood mononuclear cells (PBMCs) from healthy volunteers were stimulated with LPS, LPS with attenuated O-Antigen (RF5), or Lipid A (DPL), which lacks an O-Antigen. Selected cells were pretreated with a blocking antibody to CD14. Western blots were performed to determine activation of mitogen-activated protein kinases (MAPK) p38, ERK, and JNK at selected time-points. RNA was extracted for RT-PCR quantification of TNF-α and IL-10 gene transcription. Supernatants were harvested and analyzed by ELISA for tumor necrosis factor alpha (TNF-α) and interleukin 10 (IL-10). RESULTS: LPS elicited maximal response, including phosphorylation of p38, ERK, and JNK, synthesis of TNF-α and IL-10 mRNA, and secretion of TNF-α and IL-10. Stimulation with RF5 activated the same pathways to a lesser degree. DPL led to increased phosphorylation of p38 and ERK and increased secretion of IL-10. CD14 blockade was associated with a significant decrease in cytokine secretion by LPS, and abolished cytokine secretion in cells stimulated with RF5 or DPL. CONCLUSIONS: Structural variants of LPS activate monocyt...