N-(3-oxododecanoyl)-L-homoserine lactone disrupts intestinal epithelial barrier through triggering apoptosis and collapsing extracellular matrix and tight junction

Microbes employ autoinducers of quorum sensing (QS) for population communication. Although the autoinducer of Pseudomonas aeruginosa LasI-LasR system, N-(3-oxododecanoyl)- l-homoserine lactone (3OC12), has been reported with deleterious effects on host cells, its biological effects on integrity of the intestinal epithelium and epithelial barrier are still unclear and need further investigation. In the present study, flow cytometry, transcriptome analysis and western blot technology have been adopted to investigate the potential molecular mechanisms of 3OC12 and its structurally similar analogs damage to intestinal epithelial cells. Our results indicated that 3OC12 and 3OC14 trigger apoptosis rather than necrosis and ferroptosis in intestinal epithelial cells. RNA-sequencing combined with bioinformatics analysis showed that 3OC12 and 3OC14 reduced the expression of genes from extracellular matrix (ECM)-receptor interaction pathway. Consistently, protein expressions from ECM and tight junction-associated pathway were significantly reduced after 3OC12 and 3OC14 challenge. In addition, 3OC12 and 3OC14 led to blocked cell cycle, decreased mitochondrial membrane potential, increased reactive oxygen species level and elevated Ca2+ concentration. Reversely, the antioxidant NAC could effectively mitigate the reduced expression of ECM and tight junction proteins caused by 3OC12 and 3OC14 challenge. Collectively, this study demonstrated that QS autoinducer exposure to intestinal epithelial cells ablates the ECM and tight junctions by triggering oxidative stress and apoptosis, and finally disrupts the intestinal epithelial barrier. These findings provide a rationale for defensing QS-dependent bacterial infections and potential role of NAC for alleviating the syndrome.

Automated summary

Microbes use quorum sensing (QS) autoinducers for population communication, with N-(3-oxododecanoyl)- l-homoserine lactone (3OC12) from Pseudomonas aeruginosa LasI-LasR system having deleterious effects on intestinal epithelial cells. 3OC12 and 3OC14 trigger apoptosis rather than necrosis and ferroptosis in intestinal epithelial cells, reduce ECM-receptor interaction pathway gene expression, and decrease protein expressions from ECM and tight junction-associated pathway. Furthermore, 3OC12 and 3OC14 disrupt the intestinal epithelial barrier by inducing oxidative stress and apoptosis, with NAC showing potential for alleviating the syndrome caused by QS autoinducers exposure.