Renal tubular cell death is the key factor of the pathogenesis of ischemia/reperfusion (I/R) kidney injury. Ferroptosis is a type of regulated cell death (RCD) found in various diseases. However, the underlying molecular mechanisms related to ferroptosis in renal I/R injury remain unclear. In the present study, we investigated the regulatory role of microRNAs on ferroptosis in I/R-induced renal injury. We established the I/R-induced renal injury model in rats, and H/R induced HK-2 cells injury in vitro. CCK-8 was used to measure cell viability. Fe²⁺ and ROS levels were assayed to evaluate the activation of ferroptosis. We performed RNA sequencing to profile the miRNAs expression in H/R-induced injury and ferroptosis. Western blot analysis was used to detect the protein expression. qRT-PCR was used to detect the mRNA and miRNA levels in cells and tissues. We further used luciferase reporter assay to verify the direct targeting effect of miRNA. We found that ischemia/reperfusion-induced ferroptosis in rat’s kidney. We identified that miR-182-5p and miR-378a-3p were upregulated in the ferroptosis and H/R-induced injury, and correlates reversely with glutathione peroxidases 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11) expression in renal I/R injury tissues, respectively. In vitro studies showed that miR-182-5p and miR-378a-3p induced ferroptosis in cells. We further found that miR-182-5p and miR-378a-3p regulated the expression of GPX4 and SLC7A11 negatively by directly binding to the 3′UTR of GPX4 and SLC7A11 mRNA. In vivo study showed that silencing miR-182-5p and miR-378a-3p alleviated the I/R-induced renal injury in rats. In conclusion, we demonstrated that I/R induced upregulation of miR-182-5p and miR-378a-3p, leading to activation of ferroptosis in renal injury through downregulation of GPX4 and SLC7A11.

Antibody-mediated rejection (ABMR) and T cell-mediated rejection (TCMR) are the important causes of kidney transplant failure. Here, we aimed to evaluate the different levels and composition of infiltrating immune cells in kidney allografts of patients with ABMR or TCMR. Gene expression profiles GSE36059 and GSE48581 were obtained from the GEO database. Then, an established algorithm method called CIBERSORT was used to estimate the abundance of 22 immune cells based on microarray profiles in the GSE36059 dataset. The GSE48581 dataset was used as a validation cohort to confirm the different infiltrating immune cells between the ABMR and the TCMR groups. Receiver operating characteristic (ROC) curve analysis was used to assess the value of the infiltrating immune cells in discriminating ABMR from TCMR. Immune infiltration analysis by CIBERSORT method showed that TCMR samples had a higher level of T cell subsets compared with the ABMR samples. In the TCMR group, a significant increase in CD4 + activated memory T cells, follicular helper T cells, gamma delta (GD) T cells was observed. In the ABMR group, we found that plasma cells, resting NK cells, activated NK cells, and resting dendritic cells were increased. Similar results were also obtained in the validation cohort. The combined analysis of these infiltrating immune cells in discriminating ABMR from TCMR had an AUC of 0.839 (95% CI: 0.753–0.924) in the GSE36059 dataset and an AUC of 0.899 (95% CI: 0.823–0.975) in the validation cohort. Our data suggest that there was an obvious difference in immune infiltration between ABMR and TCMR. Plasma cells, resting NK cells, activated NK cells, resting dendritic cells, CD4 + activated memory T cells, follicular helper T cells combined with gamma delta T cells could better discriminate ABMR from TCMR.