Dipeptidase 1 promotes ferroptosis in renal tubular epithelial cells in diabetic nephropathy via inhibition of the GSH/GPX4 axis.

Renal tubular injury is an important pathological change associated with diabetic nephropathy (DN), in which ferroptosis of renal tubular epithelial cells is critical to its pathogenesis. Inhibition of the glutathione/glutathione peroxidase 4 (GSH/GPX4) axis is the most important mechanism in DN tubular epithelial cell ferroptosis, but the underlying reason for this is unclear. Our biogenic analysis showed that a zinc-dependent metalloproteinase, dipeptidase 1 (DPEP1), is associated with DN ferroptosis. Here, we investigated the role and mechanism of DPEP1 in DN tubular epithelial cell ferroptosis. DPEP1 upregulation was observed in the renal tubular epithelial cells of DN patients and model mice, as well as in HK-2 cells stimulated with high glucose. Furthermore, the level of DPEP1 upregulation was associated with the degree of tubular injury in DN patients and HK-2 cell ferroptosis. Mechanistically, knocking down DPEP1 expression could alleviate the inhibition of GSH/GPX4 axis and reduce HK-2 cell ferroptosis levels in a high glucose environment. HK-2 cells with stable DPEP1 overexpression also showed GSH/GPX4 axis inhibition and ferroptosis, but blocking the GSH/GPX4 axis could mitigate these effects. Additionally, treatment with cilastatin, a DPEP1 inhibitor, could ameliorate GSH/GPX4 axis inhibition and relieve ferroptosis and DN progression in DN mice. These results revealed that DPEP1 can promote ferroptosis in DN renal tubular epithelial cells via inhibition of the GSH/GPX4 axis.

Li Y ，Wang X ，Zhang Q ，Tian D ，Bai Y ，Feng Y ，Liu W ，Diao Z ... -  《-》

Characterization of ferroptosis in kidney tubular cell death under diabetic conditions.

Kim S ，Kang SW ，Joo J ，Han SH ，Shin H ，Nam BY ，Park J ，Yoo TH ，Kim G ，Lee P ，Park JT ... -  《-》

Hederagenin improves renal fibrosis in diabetic nephropathy by regulating Smad3/NOX4/SLC7A11 signaling-mediated tubular cell ferroptosis.

Jia J ，Tan R ，Xu L ，Wang H ，Li J ，Su H ，Zhong X ，Liu P ，Wang L ... -  《-》

Leonurine Ameliorates Diabetic Nephropathy through GPX4-Mediated Ferroptosis of Endothelial Cells.

Diabetic nephropathy (DN) is a common microvascular complication of diabetes mellitus (DM). Ferroptosis is an atypical form of iron-dependent, modulated cell death that has been shown to occur in human umbilical vein endothelial cells (HUVECs). Leonurine (LEO) is a single active ingredient extracted from Leonurus japonicus Houtt. It has various biological activities, including anti-inflammatory and anti-cancer effects. However, whether LEO affects ferroptosis in DN has yet to be investigated. An animal model of DN was established by subjecting C57/BL6 mice to a high-fat diet (HFD) while being induced with Streptozotocin (STZ). A cellular model of DN was established by exposing HUVECs to a high glucose (HG) concentration of 30 mM. LEO was found to improve DN and to attenuate the degree of glomerulosclerosis and tubular atrophy in the mouse model. Additionally, it markedly decreased the levels of ferroptosis markers. Molecular analyses revealed that LEO inhibited HG-induced oxidative stress in HUVECs, thereby decreasing endothelial cell (EC) dysfunction. Furthermore, LEO was found to reduce ferroptosis and reverse EC dysfunction by increasing the expression of glutathione peroxidase 4 (GPX4) and nuclear factor erythroid 2-related factor 2 (Nrf2). The suppression of Nrf2 in HG-induced HUVECs inhibited LEO-GPX4 axis-mediated ferroptosis and increased EC dysfunction. LEO exerts anti-DN effects both in vivo and in vitro by suppressing GPX4-mediated EC ferroptosis. Mechanistically, LEO appears to induce Nrf2-mediated GPX4 expression to inhibit ferroptosis, thereby reducing EC dysfunction. This study provides a new perspective on the treatment of diseases using natural medicines. It involves a novel form of cell death that could potentially lead to better treatment of DN.

Yu X ，Li Y ，Zhang Y ，Yin K ，Chen X ，Zhu X ... -  《-》

A Novel Identified Circular RNA, mmu_mmu_circRNA_0000309, Involves in Germacrone-Mediated Improvement of Diabetic Nephropathy Through Regulating Ferroptosis by Targeting miR-188-3p/GPX4 Signaling Axis.

Jin J ，Wang Y ，Zheng D ，Liang M ，He Q ... -  《-》