Hydroxytyrosol Restrains NLRP3 Inflammasome Activation and Pyroptosis Through the TLR4/NF-κB Pathway to Prevent Mycoplasma gallisepticum-Inflammation.

Abstract

Mycoplasma gallisepticum (MG), a significant pathogen, causes chronic respiratory disease (CRD) in poultry, characterized by coughing, wheezing, and dyspnea. This widespread disease severely impedes the healthy development of the poultry industry. Hydroxytyrosol (HT), a plant-derived monomeric compound, possesses diverse bioactivities, including antibacterial, antioxidant, and cardiovascular protective properties. This study aimed to investigate HT's protective effect against MG-induced inflammatory damage in HD11 cells. The findings revealed that MG infection activated the TLR4/NF-κB signaling pathway and the NLRP3 inflammasome, resulting in macrophage accumulation and inflammatory damage in the lung tissue of chicks. HT mitigated MG-induced inflammatory damage in HD11 cells, inhibited the M1 phenotype shift, and reduced the secretion of pro-inflammatory factors. Molecular docking and molecular dynamics simulations demonstrated HT's stable, spontaneous binding to NLRP3. Further investigations showed that HT alleviates oxidative stress-induced cellular damage, diminishes pathological apoptosis and pore formation, and concurrently reduces NLRP3 activation by regulating the TLR4/NF-κB pathway, thereby downregulating the expression of key pyroptosis factors. In summary, HT reduces NLRP3 inflammasome activation by specifically inhibiting the TLR4/NF-κB signaling axis, consequently alleviating inflammation-induced damage, oxidative stress, and pyroptosis in HD11 cells caused by MG infection.