Effects of DON on Mitochondrial Function, Endoplasmic Reticulum Stress, and Endoplasmic Reticulum Mitochondria Contact Sites in the Jejunum of Piglets

Recent research has emphasized the significance of investigating the interplay between organelles, with endoplasmic reticulum mitochondria contact sites (ERMCSs) being recognized as critical signaling hubs between organelles. The objective of the current study was to assess the impact of deoxynivalenol (DON) on jejunal mitochondria, ER, and ERMCSs. Twelve piglets (35 d, 10.22 ± 0.35 kg) were randomized into two groups: control group, basal diet; the DON group, basal diet + 1.5 mg/kg DON. The findings revealed that DON decreased growth performance, induced jejunal oxidative stress, and impaired jejunal barrier function. DON was also found to induce mitochondrial dysfunction, trigger endoplasmic reticulum stress (ERS) in the piglets' jejunum, and activate mitochondrial and ER apoptosis pathways by upregulating apoptosis-related proteins (Caspase-8, Caspase-12, Bax, and CHOP). To investigate the involvement of ERMCSs in DON-induced intestinal injury, we measured the protein levels of ERMCS proteins, such as mitofusin 1 (Mfn1), mitofusin 2 (Mfn2), and glucose-regulated protein 75 (GRP75) and Pearson's correlation coefficient of ERMCS proteins and ERMCS ultrastructure. Our finding showed that DON upregulated the protein level of Mfn2 and GRP75 and increased the percentage of mitochondria with ERMCSs/total mitochondria, the length of ERMCSs compared to the perimeter of mitochondria, and the Pearson's correlation coefficient of voltage-dependent anion-selective channel protein 1 (VDAC1) and inositol 1,4,5-triphosphate receptors (IP3Rs) in piglets' jejunum. Furthermore, DON shortened the distance between mitochondria and ER at ERMCSs. These findings suggested that DON impaired mitochondrial function, triggered ERS, and increased ERMCSs, indicating that the increased ERMCSs could be related to mitochondrial dysfunction and ERS involved in the intestinal injury of piglets induced by DON.