OBJECTIVE: Exploring the changes in cerebellar ferroptosis in hypertensive mice after lead exposure.
METHODS: Twenty-five healthy C57 male mice were selected to construct a hypertensive model by intraperitoneal injection of angiotensin II(Ang II) at a concentration of 0.05 mg/kg for 7 consecutive days. After a systolic blood pressure of 140 mmHg, 20 hypertensive mice were randomly divided into a hypertensive control group and a hypertensive lead exposure group. Twenty C57 mice with normal blood pressure were randomly divided into a blood pressure normal control group and a blood pressure normal lead exposure group. The mice in the normal blood pressure control group and the hypertensive control group drank water freely. Mice in the lead exposure group with normal blood pressure and the lead exposure group with hypertension drank lead acetate water containing 250 mg/L. Ang II was injected intraperitoneally every two days in the hypertensive control group and hypertensive lead exposed group mice. Each group of mice was poisoned for 12 weeks. Using open field experiments and balance beam experiments to detect motor dysfunction in mice. Using a reagent kit to detect the levels of divalent iron(Fe~(2+)), malondialdehyde(MDA), and glutathione(GSH) in the cerebellum of different groups of mice. Western blot was used to determine the protein expression of member 11 of the solute carrier family 7(SLC7A11), glutathione peroxidase 4(GPX4), nuclear receptor coactivator 4(NCOA4), microtubule associated protein 1 light chain 3B(LC3B), and ferritin heavy chain 1(FTH1) in mouse cerebellar tissue.
RESULTS: The result of the open field experiment showed that the activity distance(1013.04 cm) of mice in the hypertensive lead exposure group was significantly lower than that of the hypertensive control group(1351.18 cm) and the lead exposure group with normal blood pressure(1287.35 cm). And the lead exposure group with hypertension also extended the time through the balance beam, which was 29.40 seconds(P<0.05). In addition, the Fe~(2+)content in the cerebellum of mice in the hypertensive lead exposure group was 3.33 μmol/g prot, which was 1.54 times that of the hypertensive control group and 1.14 times that of the lead exposure group with normal blood pressure. The MDA content was 4.71 nmol/mg prot, higher than that of the hypertensive control group and the lead exposure group with normal blood pressure. The GSH content was 5.36 μmol/g prot, lower than that of the hypertensive control group and the lead exposure group with normal blood pressure(P<0.05). Western blot result showed that compared with the hypertensive control group and the lead exposure group with normal blood pressure, the protein expression of SLC7A11 and GPX4 in the hypertensive lead exposure group was significantly reduced(P<0.05). In addition, compared with the control group with normal blood pressure, the expression of NCOA4 and LC3B proteins in the cerebellum of mice in the hypertension control group and lead exposure group with normal blood pressure increased, while the expression of FTH1 protein decreased(P<0.05). The expression of NCOA4 and LC3B proteins in the hypertensive lead exposure group was higher than that in the hypertensive control group and the lead exposure group with normal blood pressure, while the expression of FTH1 protein decreased(P<0.05).
CONCLUSIONS: Lead exposure can exacerbate iron death in the cerebellar tissue of hypertensive mice, and iron autophagy may be involved in its occurrence and development.

Ferritinophagy is a selective form of autophagy in which ferritin, the primary intracellular iron storage protein complex, is targeted by NCOA4 (Nuclear receptor coactivator 4) to the lysosome for degradation. NCOA4-mediated ferritinophagy plays a crucial role in cellular iron metabolism, influencing iron homeostasis, heme synthesis, mitochondrial respiratory function, and ferroptosis, an iron-dependent form of cell death. Targeting ferritinophagy has emerged as a potential anticancer therapeutic strategy. In this context, we provide a flowchart of the procedures and accompanying protocols for monitoring ferritinophagic flux.

Acute kidney injury (AKI) is a significant issue in public health, displaying a high occurrence rate and mortality rate. Ferroptosis, a form of programmed cell death (PCD), is characterized by iron accumulation and intensified lipid peroxidation. Recent studies have demonstrated the pivotal significance of ferroptosis in AKI caused by diverse stimuli, including ischemia-reperfusion injury (IRI), sepsis and toxins. Autophagy, a multistep process that targets damaged organelles and macromolecules for degradation and recycling, also plays an essential role in AKI. Previous research has demonstrated that autophagy deletion in proximal tubules could aggravate tubular injury and renal function loss, indicating the protective function of autophagy in AKI. Consequently, finding ways to stimulate autophagy has become a crucial therapeutic strategy. The recent discovery of the role of selective autophagy in influencing ferroptosis has identified new therapeutic targets for AKI and has highlighted the importance of understanding the cross-talk between autophagy and ferroptosis. This study aims to provide an overview of the signaling pathways involved in ferroptosis and autophagy, focusing on the mechanisms and functions of selective autophagy and autophagy-dependent ferroptosis. We hope to establish a foundation for future investigations into the interaction between autophagy and ferroptosis in AKI as well as other diseases.

BACKGROUND: Pancreatic cancer (PC) is characterized by a poor prognosis and limited treatment options. Ferroptosis plays an important role in cancer, SET and MYND domain-containing protein 2 (SMYD2) is widely expressed in various cancers. However, the role of SMYD2 in regulating ferroptosis in PC remains unexplored. This study aimed to investigate the role of SMYD2 in mediating ferroptosis and its mechanistic implications in PC progression.
METHODS: The levels of SMYD2, c-Myc, and NCOA4 were assessed in PC tissues, and peritumoral tissues. SMYD2 expression was further analyzed in human PC cell lines. In BxPC3 cells, the expression of c-Myc, NCOA4, autophagy-related proteins, and mitochondrial morphology, was evaluated following transfection with si-SMYD2 and treatment with autophagy inhibitors and ferroptosis inhibitors. Ferroptosis levels were quantified using flow cytometry and ELISA assays. RNA immunoprecipitation was conducted to elucidate the interaction between c-Myc and NCOA4 mRNA. A xenograft mouse model was constructed to validate the impact of SMYD2 knockdown on PC growth.
RESULTS: SMYD2 and c-Myc were found to be highly expressed in PC tissues, while NCOA4 showed reduced expression. Among the PC cell lines studied, BxPC3 cells exhibited the highest SMYD2 expression. SMYD2 knockdown led to decreased c-Myc levels, increased NCOA4 expression, reduced autophagy-related protein expression, mitochondrial shrinkage, and heightened ferroptosis levels. Additionally, an interaction between c-Myc and NCOA4 was identified. In vivo, SMYD2 knockdown inhibited tumor growth.
CONCLUSIONS: Targeting SMYD2 inhibits PC progression by promoting ferritinophagy-dependent ferroptosis through the c-Myc/NCOA4 axis. These findings provide insights into potential diagnostic and therapeutic strategies for PC.

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Acute kidney injury (AKI) is closely related to lysosomal dysfunction and ferroptosis in renal tubular epithelial cells (TECs), for which effective treatments are urgently needed. Although selenium nanoparticles (SeNPs) have emerged as promising candidates for AKI therapy, their underlying mechanisms have not been fully elucidated. Here, we investigated the effect of SeNPs on hypoxia/reoxygenation (H/R)-induced ferroptosis and lysosomal dysfunction in TECs in vitro and evaluated their efficacy in a murine model of ischemia/reperfusion (I/R)-AKI. We observed that H/R-induced ferroptosis was accompanied by lysosomal Fe2+ accumulation and dysfunction in TECs, which was ameliorated by SeNPs administration. Furthermore, SeNPs protected C57BL/6 mice against I/R-induced inflammation and ferroptosis. Mechanistically, we found that lysosomal Fe2+ accumulation and ferroptosis were associated with the excessive activation of NCOA4-mediated ferritinophagy, a process mitigated by SeNPs through the upregulation of X-box binding protein 1 (XBP1). Downregulation of XBP1 promoted ferritinophagy and partially counteracted the protective effects of SeNPs on ferroptosis inhibition in TECs. Overall, our findings revealed a novel role for SeNPs in modulating ferritinophagy, thereby improving lysosomal function and attenuating ferroptosis of TECs in I/R-AKI. These results provide evidence for the potential application of SeNPs as therapeutic agents for the prevention and treatment of AKI.

OBJECTIVE: While copper (Cu) is essential for biological organisms, excessive Cu can be harmful. Ferroptosis is a programmed cell death pathway, but the role of ferroptosis in renal injury induced by Cu is limited. The aim of this study was to investigate the role of ferroptosis in kidney injury in chickens and the molecular mechanism by which Cu promotes renal ferroptosis.
METHODS: Chicken were subjected to Cu treatment by artificially adding excess Cu to the basal diet (the Cu concentration in the diet was supplemented to 110-330 mg/kg), and the impact on kidney fibrosis, tissue structure, and ferroptosis-related molecular markers was studied. Then, the expression levels of genes and proteins related to ferroptosis, iron metabolism and ferroautophagy were detected to explore the promoting effect of Cu on ferroptosis in chicken kidney.
RESULTS: Cu treatment resulted in significant fibrosis and tissue structure damage in chicken kidneys. Molecular analysis revealed a significant upregulation of LC3Ⅱ, P62, ATG5, and NCOA4, along with a decrease in FTH1 and FTL protein levels. Additionally, crucial markers of ferroptosis, including the loss of GPX4, SLC7A11, and FSP1, and an increase in PTGS2 and ACSL4 protein levels, were observed in chicken kidneys after Cu exposure.
CONCLUSIONS: Our study showed that dietary Cu excess caused kidney injury in brochickens and exhibited ferroptosis-related features, including lipid peroxidation, reduction of ferritin, and downregulation of FSP1 and GPX4. These results indicate that excess Cu can induce renal ferroptosis and lead to kidney injury in chickens. This study highlights the complex interplay between Cu ions and ferroptosis in the context of renal injury and provides a new perspective for understanding the mechanism of Cu-induced renal injury.

In recent years, the emerging phenomenon of ferroptosis has garnered significant attention as a distinctive mode of programmed cell death. Distinguished by its reliance on iron and dependence on reactive oxygen species (ROS), ferroptosis has emerged as a subject of extensive investigation. Mechanistically, this intricate process involves perturbations in iron homeostasis, dampening of system Xc-activity, morphological dynamics within mitochondria, and the onset of lipid peroxidation. Additionally, the concomitant phenomenon of ferritinophagy, the autophagic degradation of ferritin, assumes a pivotal role by facilitating the liberation of iron ions from ferritin, thereby advancing the progression of ferroptosis. This discussion thoroughly examines the detailed cell structures and basic processes behind ferroptosis and ferritinophagy. Moreover, it scrutinizes the intricate web of regulators that orchestrate these processes and examines their intricate interplay within the context of joint disorders. Against the backdrop of an annual increase in cases of osteoarthritis, rheumatoid arthritis, and gout, these narrative sheds light on the intriguing crossroads of pathophysiology by dissecting the intricate interrelationships between joint diseases, ferroptosis, and ferritinophagy. The newfound insights contribute fresh perspectives and promising therapeutic avenues, potentially revolutionizing the landscape of joint disease management.

Ferroptosis, characterized by the accumulation of reactive oxygen species and lipid peroxidation, is involved in various cardiovascular diseases. (Pro)renin receptor (PRR) in performs as ligands in the autophagic process, and its function in diabetic cardiomyopathy (DCM) is not fully understood. We investigated whether PRR promotes ferroptosis through the nuclear receptor coactivator 4 (NCOA 4)-mediated ferritinophagy pathway and thus contributes to DCM. We first established a mouse model of DCM with downregulated and upregulated PRR expression and used a ferroptosis inhibitor. Myocardial inflammation and fibrosis levels were then measured, cardiac function and ferroptosis-related indices were assessed. In vitro, neonatal rat ventricular primary cardiomyocytes were cultured with high glucose and transfected with recombinant adenoviruses knocking down or overexpressing the PRR, along with a ferroptosis inhibitor and small interfering RNA for the ferritinophagy receptor, NCOA4. Ferroptosis levels were measured in vitro. The results showed that the knockdown of PRR not only alleviated cardiomyocyte ferroptosis in vivo but also mitigated the HG-induced ferroptosis in vitro. Moreover, administration of Fer-1 can inhibit HG-induced ferroptosis. NCOA4 knockdown blocked the effect of PRR on ferroptosis and improved cell survival. Our result indicated that inhibition of PRR and NCOA4 expression provides a new therapeutic strategy for the treatment of DCM. The effect of PRR on the pathological process of DCM in mice may be in promoting cardiomyocyte ferroptosis through the NCOA 4-mediated ferritinophagy pathway.

Iron homeostasis is vital for the host\'s defense against pathogenic invasion and the ferritinophagy is a crucial mechanism in maintaining intracellular iron homeostasis by facilitating the degradation and recycling of stored iron. The nuclear receptor coactivator 4 (NCOA4) serves as a ferritinophagy receptor, facilitating the binding and delivery of ferritin to the autophagosome and lysosome. However, NCOA4 of the sea cucumber Apostichopus japonicus (AjNCOA4) has not been reported until now. In this study, we identified and characterized AjNCOA4 in A. japonicus. This gene encodes a polypeptide containing 597 amino acids with an open reading frame of 1794 bp. The inferred amino acid sequence of AjNCOA4 comprises an ARA70 domain. Furthermore, a multiple sequence alignment demonstrated varying degrees of sequence homology between AjNCOA4 from A. japonicus and other NCOA4 orthologs. The phylogenetic tree of NCOA4 correlates with the established timeline of metazoan evolution. Expression analysis revealed that AjNCOA4 is expressed in all tested tissues, including the body wall, muscle, intestine, respiratory tree, and coelomocytes. Following challenge with Vibrio splendidus, the coelomocytes exhibited a significant increase in AjNCOA4 mRNA levels, peaking at 24 h. We successfully obtained recombinant AjNCOA4 protein through prokaryotic expression and prepared a specific polyclonal antibody. Immunofluorescence and co-immunoprecipitation experiments demonstrated an interaction between AjNCOA4 and AjFerritin in coelomocytes. RNA interference-mediated knockdown of AjNCOA4 expression resulted in elevated iron ion levels in coelomocytes. Bacterial stimulation enhanced ferritinophagy in coelomocytes, while knockdown of AjNCOA4 reduced the occurrence of ferritinophagy. These findings suggest that AjNCOA4 modulates ferritinophagy induced by V. splendidus in coelomocytes of A. japonicus.