N-(3-Oxododecanoyl)-Homoserine Lactone Induces Intestinal Barrier Damage in Piglets via the Lipid Raft-Mediated Apoptosis Pathway

Simple SummaryQuorum sensing (QS) not only regulates bacterial virulence through signaling molecules, but is also capable of causing direct damage to host cells. Previous studies have found a high correlation between N-acyl homoserine lactone (AHL) of the QS in the piglet intestine and piglet health. In a mouse model, AHL signaling N-(3-oxododecanoyl)-homoserine lactone (OdDHL) induced apoptosis of intestinal cells and damage to intestinal barrier. In a porcine intestinal epithelial cell model, OdDHL also was confirmed to induce apoptosis. The direct role and mechanism of OdDHL in the digestive tract of porcine animal models have not been elucidated. For the first time in a piglet model, we have verified that AHL induces apoptosis and disrupts the intestinal barrier, and we have also verified the protective effect of QS inhibitors. The present study also investigates the central role of cellular lipid rafts in the critical phase in which OdDHL adheres to cells and exerts functions. In cells where lipid rafts were eliminated, the ability of OdDHL adherence to cell surface was significantly reduced, and apoptosis induction was similarly impaired. This result indicates an important role for lipid rafts in relevant processes. This study provides basic data for the antimicrobial application of QSI in pig farming.Quorum sensing (QS) is a process by which bacteria sense their population density and regulate behavior accordingly. QS not only regulates bacterial virulence but also directly influences host cells. Previous studies have shown that QS is strongly associated with piglet intestinal health, but the mechanism is not yet clear. For the first time, we have confirmed in a piglet animal model that OdDHL directly damages intestinal cells in weaned piglets, disrupting the intestinal barrier. We also provide a preliminary exploration of the underlying mechanism of these effects. TUNEL assays confirmed that damage to the piglet intestinal barrier coincided temporally and spatially with dysregulated apoptosis. Lipid rafts, key components of the cell membrane, are involved in many biological processes, including the activation of apoptosis-related proteins. Following the disruption of the lipid raft structure in IPEC-J2 cells, the apoptosis rate under OdDHL stimulation decreased by 50%. These data demonstrate that lipid rafts mediate the attachment of OdDHL to porcine intestinal cells; then, OdDHL induces apoptosis in porcine intestinal cells through the mitochondrial and death receptor pathways, thereby compromising the integrity of the porcine intestinal barrier. This study provides foundational insights into the role of QS in piglet intestinal diseases.