Stanniocalcin-1 Overexpression Protects Porcine Intestinal Epithelial Cells Against TBHP-Induced Oxidative Stress by Preserving Mitochondrial Homeostasis

Stanniocalcin-1 (STC-1) is a multifunctional glycoprotein; however, its role in protecting intestinal epithelial cells against oxidative injury has not been completely elucidated. This study investigated the cytoprotective effects and underlying molecular mechanisms of STC-1 overexpression in porcine intestinal epithelial (IPEC-J2) cells subjected to tert-butyl hydroperoxide (TBHP)-induced oxidative stress. IPEC-J2 cells were transfected with pcDNA3.1/STC-1 prior to TBHP challenge. STC-1 overexpression markedly rescued cells from TBHP-induced cytotoxicity and cell death, and was associated with a reduced Bax/Bcl-2 ratio. Concurrently, elevated STC-1 expression dramatically suppressed intracellular reactive oxygen species and mitochondrial superoxide accumulation while preserving the mitochondrial membrane potential. These physiological improvements were accompanied by enhanced total antioxidant capacity and activities of key antioxidant enzymes. Mechanistically, STC-1 overexpression enhanced autophagic flux and promoted Pink1/Parkin-mediated mitophagy to eliminate dysfunctional mitochondria. Furthermore, STC-1 upregulation potentiated the AMPK–Nrf2/Sirt1 signaling axis and the subsequent transcriptional upregulation of mitochondrial quality control markers, including FoxO1, PGC-1α, and TFAM, under stress conditions. Collectively, these findings demonstrate that STC-1 safeguards porcine intestinal cells against oxidative injury by orchestrating a cooperative defense network encompassing ROS scavenging, mitochondrial homeostasis, and antioxidant defense amplification via the AMPK–Nrf2/Sirt1 pathway, highlighting a potential therapeutic target for preventing stress-associated intestinal disorders in piglets.