Ferroptosis, but Not Necroptosis, Is Important in Nephrotoxic Folic Acid–Induced AKI

Abstract

AKI is histologically characterized by necrotic cell death and inflammation. Diverse pathways of regulated necrosis have been reported to contribute to AKI, but the molecular regulators involved remain unclear. We explored the relative contributions of ferroptosis and necroptosis to folic acid (FA)-induced AKI in mice. FA-AKI in mice associates with lipid peroxidation and downregulation of glutathione metabolism proteins, features that are typical of ferroptotic cell death. We show that ferrostatin-1 (Fer-1), an inhibitor of ferroptosis, preserved renal function and decreased histologic injury, oxidative stress, and tubular cell death in this model. With respect to the immunogenicity of ferroptosis, Fer-1 prevented the upregulation of IL-33, an alarmin linked to necroptosis, and other chemokines and cytokines and prevented macrophage infiltration and Klotho downregulation. In contrast, the pancaspase inhibitor zVAD-fmk did not protect against FA-AKI. Additionally, although FA-AKI resulted in increased protein expression of the necroptosis mediators receptor-interacting protein kinase 3 (RIPK3) and mixed lineage domain-like protein (MLKL), targeting necroptosis with the RIPK1 inhibitor necrostatin-1 or genetic deficiency of RIPK3 or MLKL did not preserve renal function. Indeed, compared with wild-type mice, MLKL knockout mice displayed more severe AKI. However, RIPK3 knockout mice with AKI had less inflammation than their wild-type counterparts, and this effect associated with higher IL-10 concentration and regulatory T cell-to-leukocyte ratio in RIPK3 knockout mice. These data suggest that ferroptosis is the primary cause of FA-AKI and that immunogenicity secondary to ferroptosis may further worsen the damage, although necroptosis-related proteins may have additional roles in AKI.

The Endocannabinoid, Anandamide, Induces Cannabinoid Receptor-Independent Cell Death in Renal Proximal Tubule Cells

“…Figure 1). Surprisingly, we did not find any significant changes between the control tissues and the diseased kidneys despite inflammatory alterations in interstitial nephritis or immunologic destruction of proximal tubuli in rat renal transplants, which is in contrast to the aforementioned findings after toxic [15] or metabolic [34] tubular injury.…”

“…Martin-Sanchez and colleagues verify ferroptosis as the dominant cell death mechanism in acute kidney injury [15]. Acute injury occurring in diabetic nephropathy with subsequent tubular inflammation can lead to a local upregulation of the endocannabinoid system [34].…”

“…Ferroptosis is associated with: ROS accumulation, activation of mitogen activated protein kinases (MAPK), release of arachidonic acid metabolites, glutathione (GSH) dependence as well as small mitochondria [20], and can be blocked by Ferrostatin-1 (Fer-1) through the reduction of lipid oxidation [15].…”

Metabolic networks in ferroptosis (Review)

“…In acute kidney failure, hemorrhagic stroke and nephrotoxic folic acid induce acute kidney injury, and inhibitors of ferroptosis (for example, ferrostatin-1) reduce the damage caused by cell sabotage. Ferrostatin-1 preserves renal function and decreases injury, oxidative stress and tubular cell death in mice with nephrotoxic folic acid-induced acute kidney injuries (17,58,59). Therefore, ferrostatin-1 may have a prophylactic effect in these non-neoplastic diseases.…”

Not all extracellular vesicles were created equal: clinical implications

“…Another possibility is that doxorubicin also caused immunogenic forms of cell death, such as necroptosis. In this regard, lethal stimuli may cause both apoptosis and necroptosis within the same cell culture (25,26). While the generation of vesicles by necroptotic cells has not been described, it is conceivable the simultaneous occurrence of apoptosis and necroptosis may result in the generation immunogenic apoptosis vesicles.…”