Platelet‐neutrophil Interaction Aggravates Vascular Inflammation and Promotes the Progression of Atherosclerosis by Activating the TLR4/NF‐κB Pathway

Platelet‐neutrophil interaction is well known for its role in inflammatory diseases; however, its biological role in atherosclerosis (AS) progression remains unclear. Human peripheral blood neutrophils were obtained to compare toll‐like receptor 4 (TLR4), tumor necrosis factor α (TNF‐α), interleukin (IL)‐1β and myeloid‐related proteins 8/14 (Mrp8/14) levels in 22 AS patients with those in 18 healthy controls using quantitative real‐time polymerase chain reaction (qRT‐PCR) and enzyme‐linked immunosorbent assay (ELISA). Meanwhile, mouse marrow neutrophils subjected to different treatment were collected for the ELISA assay, cell apoptosis, and Western blot analysis. Normal diet or high‐fat diet ApoE−/− mice with or without administration of Mrp8/14 antagonist paquinimod were used for plasma collection to measure total cholesterol, triglycerides, low‐density lipoprotein cholesterol and high‐density lipoprotein cholesterol, TNF‐α, IL‐1β, Mrp8/14, TLR4, and nuclear factor (NF)‐κB p65 levels. The results showed that Mrp8/14 and TLR4‐mediated inflammatory pathway was activated in neutrophils of AS patients. In vitro experiments demonstrated that platelet‐neutrophil interaction promoted the Mrp8/14 release and inhibited neutrophil apoptosis via P‐selectin. Furthermore, platelet‐neutrophil interaction upregulated TLR4/myeloid differentiation factor 88/NF‐κB pathway. Conversely, Mrp8/14/TLR4/NF‐κB interference alleviated AS progression. In conclusion, Mrp8/14/TLR4/NF‐κB activated by platelet‐neutrophil interaction is an important inflammatory signaling pathway for AS pathogenesis.