Porcine epidemic diarrhea virus (PEDV) induces enteritis and diarrhea in piglets. Mitochondrial DNA (mtDNA) contributes to virus-induced inflammatory responses; however, the involvement of inflammasomes in PEDV infection responses remains unclear. We investigated the mechanism underlying inflammasome-mediated interleukin (IL)-1β secretion during the PEDV infection of porcine intestinal epithelial (IPEC-J2) cells. IL-1β production and caspase-1 activity were assessed by quantitative PCR and enzyme-linked immunosorbent assay. NLRP3 inflammasome activation was assessed using immunoprecipitation experiments. Mitochondrial damage was evaluated by analyzing the mitochondrial membrane potential and ATP levels and by the flow cytometry examination of mitochondrial reactive oxygen species (mtROS). Mitochondria and mtDNA localization were observed using immunofluorescence. The inhibition of mtROS and mtDNA production allowed NLRP3 inflammasome and IL-1β expression detection and the evaluation of the pathway underlying NLRP3 inflammasome activation in PEDV-infected IPEC-J2 cells. IPEC-J2 cells upregulated IL-1β upon PEDV infection, where mature IL-1β secretion depended on caspase-1 activity, triggered NLRP3 inflammasome expression and assembly, and caused mitochondrial dysfunction, leading to mtDNA release and NLRP3 inflammasome activation, while mtROS contributed to NF-κB pathway activation, enhancing IL-1β secretion. This is the first demonstration of the mechanism underlying mtDNA release and NLRP3 inflammasome activation facilitating IL-1β secretion from PEDV-infected IPEC-J2 cells. These data enhance our understanding of the inflammatory mechanisms triggered by PEDV.

Infectious bovine rhinotracheitis virus (IBRV) causes highly contagious bovine respiratory disease and threatens the global cattle industry. Ferroptosis, an iron-dependent regulated cell death, is involved in multiple viral infections, but its role and mechanism in IBRV infection remain unclear. This study investigated IBRV-induced ferroptosis and the NFKB1-SLC39A8 axis in MDBK cells and examined the effect of ferroptosis on IBRV replication. Ferroptotic phenotypes and molecules were detected by biochemical assays, qPCR, Western blotting and TEM. Gain- and loss-of-function assays were performed to modulate gene expression, and their transcriptional relationship was verified by dual-luciferase assay. IBRV induced typical ferroptosis in MDBK cells, including Fe²⁺ overload, excessive ROS and MDA accumulation, GSH depletion and mitochondrial damage. Ferrostatin-1 reversed these changes and reduced viral titers, suggesting that ferroptosis contributes to IBRV replication. SLC39A8 overexpression aggravated ferroptosis, whereas its knockdown suppressed it. Mechanistically, our data support that NFKB1 positively regulates SLC39A8 transcription, and NFKB1 silencing inhibited IBRV-induced ferroptosis. In conclusion, this in vitro study shows that IBRV induces ferroptosis in MDBK cells via the NFKB1-SLC39A8 axis, and ferroptosis may contribute to viral replication. These findings provide insights into IBRV–host cellular interaction and identify potential candidate molecular targets for future antiviral research.