Selenium Nanoparticles Alleviate Intestinal Epithelial Barrier Dysfunction by Coordinating Mitochondria-lysosome...

Intestinal barrier homeostasis is closely associated with coordinated signaling between mitochondria and lysosomes. Although our previous studies demonstrated the barrier-protective effects of biogenic selenium nanoparticles (SeNPs), the inter-organelle signaling mechanisms underlying this protection under dual-organelle stress remain unclear. In the present study, we established a targeted dual-injury model in IPEC-J2 cells using chloroquine (CQ) and 2,4-dinitrophenol (DNP) to investigate the signaling events governing mitochondria-lysosome communication. Combined exposure to CQ and DNP profoundly disrupted organelle homeostasis, as evidenced by severe adenosine triphosphate (ATP) depletion, elevated intracellular reactive oxygen species (ROS) and mitochondrial superoxide production, impaired lysosomal acidification, and altered autophagy-related processes. These synergistic insults ultimately promoted apoptosis, induced tight junction disassembly, and increased epithelial permeability. Notably, SeNPs pretreatment significantly upregulated the mRNA expression of key selenoproteins, including SELENOF, SELENOS, and SELENOP, and restored the activities of the selenium-dependent antioxidant enzymes glutathione peroxidase (GPx) and thioredoxin reductase (TrxR). This restoration of antioxidant capacity attenuated intracellular ROS and mitochondrial superoxide accumulation and restored the bioenergetic support required for autophagy-related processes and lysosomal acidification. Mechanistically, restoration of intracellular redox homeostasis by SeNPs prevented oxidative stress-induced dissociation of the TBC1D15/Rab7/Fis1 complex, a key tethering axis involved in mitochondria-lysosome communication. Stabilization of this complex was accompanied by improved autophagy-lysosome homeostasis and preservation of intestinal epithelial barrier integrity. Collectively, these findings demonstrate that biogenic SeNPs preserve intestinal epithelial barrier integrity under dual-organelle stress by enhancing selenoprotein-mediated antioxidant defense, thereby stabilizing mitochondria-lysosome tethering and restoring inter-organelle communication.