Validation of pIgR as a direct target of miR-221-5P in IPEC-J2 cells. (A) Bioinformatics analyses predicted binding Scheme 221. p and pIgR, miR-221-5p and circ-XPO4. (B) Dual luciferase reporter system detects the targeting relationship between miR-221-5p and pIgR (n = 8). (C,D) qRT-PCR analysis of miR-221-5p and pIgR expression levels in IPEC-J2 cell treated with NC, miR-221-5p mimics or miR-221-5p inhibitors (n = 6). (E,F) Western Blotting analysis of pIgR protein levels in IPEC-J2 cell treated with NC, miR-221-5p mimics or miR-221-5p inhibitors (n = 4). All data are presented as means ± SEM. ** p < 0.01. Different superscripts “a”/“b”/“c” represent significant differences between groups (p < 0.05).