TIGAR Protects Against Adenine-Induced Ferroptosis in Human Proximal Tubular Epithelial Cells by Activating the mTOR/S6KP70 Axis.

TP53-induced glycolysis and apoptosis regulator (TIGAR) acts as a switch for nephropathy, but its underlying mechanism is still unclear. The purpose of this study was to explore the potential biological significance and underlying mechanism of TIGAR in modulating adenine-induced ferroptosis in human proximal tubular epithelial (HK-2) cells. HK-2 cells under- or overexpressing TIGAR were challenged with adenine to induce ferroptosis. The levels of reactive oxygen species (ROS), iron, malondialdehyde (MDA), and glutathione (GSH) were assayed. Expression of ferroptosis-associated solute carrier family seven-member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4) at the level of mRNA and protein were measured by quantitative real-time-PCR and western blotting. The phosphorylation levels of proteins in the mTOR/S6KP70 pathway were determined by western blotting. Adenine overload triggered ferroptosis in HK-2 cells, as evidenced by reduced levels of GSH, SLC7A11, and GPX4, and increased levels of iron, MDA, and ROS. TIGAR overexpression repressed adenine-induced ferroptosis and induced mTOR/S6KP70 signaling. Inhibitors of mTOR and S6KP70 weakened the ability of TIGAR to inhibit adenine-induced ferroptosis. TIGAR inhibits adenine-induced ferroptosis in human proximal tubular epithelial cells by activating the mTOR/S6KP70 signaling pathway. Therefore, activating the TIGAR/mTOR/S6KP70 axis may be a treatment for crystal nephropathies.

[Effect of activation of cellular immunity on p58+ cells expressing killer-cell-inhibitory receptor cells].

UNLABELLED: The purpose of this study was to evaluate the effects of cellular immunity activation on P58(+) cells expressing killer cell inhibitory receptor (KIR) and their regulatory function on cellular immunity, and provid theoretical data for preventing graft-vers-host disease (GVHD) in stem cell transplantation therapy. The mononuclear cells from human peripheral blood were incubated with IL-2, Con A and Lipostin (LP) for 72 hours. The KIR expressing cells, P58.1(+) and P58.2(+) cells, were analyzed by flow cytometry. The results showed that the percentages of CD3(+), CD4(+), CD8(+), CD16(+)CD56(+), P58.1(+) and P58.2(+) cells were greatly increased after treated with IL-2, Con A and LP, separately or in combination, and the percentages of above cells in combined treatment groups were higher than those of single stimulated groups, especially the percentage of cells in the IL-2 + LP group was significantly higher than those in IL-2 and LP singly treated groups. IN CONCLUSION: IL-2, Con A and LP possess the ability to induce the expression of KIR and stimulate proliferation of P58.1(+) and P58.2(+) cells while to activate the celluar immunity response, the expression of P58 gene may be regulated by the activation of cellular immunity.