OBJECTIVES:Liver fibrosis is a risk factor leading to cirrhosis and even liver cancer. Pterostilbene (PTE) is a stilbenoid compound derived from blueberries and grapes. However, whether PTE can alleviate liver fibrosis, inhibit the activation of hepatic stellate cells (HSCs), and its potential mechanisms are still unclear. MATERIALS AND METHODS:In vivo, liver fibrosis was induced in mice using carbon tetrachloride (CCl₄) to assess the anti-fibrotic effects of PTE. In vitro, TGF-β1-activated LX-2 cells were treated with PTE, and ferroptosis inhibitors were applied to further examine PTE's anti-fibrotic action. RESULTS:In vivo, PTE alleviated CCl₄-induced liver injury and inflammation, and reduced the degree of liver fibrosis. In vitro, PTE inhibited LX-2 cell activity and attenuated fibrosis-related protein expression. Further studies revealed that PTE's inhibitory effect on LX-2 cells was associated with ferroptosis, manifested by GSH depletion, MDA generation, ROS production, and lipid peroxidation accumulation. Mechanistically, we found that PI3K/Akt signaling pathway is a critical regulator in PTE-induced ferroptosis in LX-2 cells. After activating the expression of PI3K in LX-2 cells, PTE lost its ability to induce ferroptosis and its anti-fibrotic function. CONCLUSIONS:PTE inhibits CCl4-induced liver fibrosis by targeting PI3K/Akt to induce ferroptosis in HSCs. These findings indicate that PTE is a promising candidate for the treatment of liver fibrosis.

BACKGROUND AND AIMS:Aging can exacerbate hepatic ischemia-reperfusion injury (HIRI), but the underlying mechanisms remain uncertain. In this study, the mechanisms through which age-related dysregulation of the GSK3β-Nrf2 axis promotes hepatocyte ferroptosis and exacerbates HIRI were investigated. METHODS:We used a comparative approach to analyze the following: 1) human liver specimens from young (25-35 years) and elderly (65-75 years) donors; 2) young and aged C57BL/6 mice and Nrf2-knockout (Nrf2-KO) mouse models subjected to HIRI; and 3) radiation-induced senescent L02 hepatocytes. Key interventions included the administration of the ferroptosis inhibitor ferrostatin-1 (Fer-1) and the GSK3β inhibitor lithium (LiCl). RESULTS:Our study revealed that aging leads to significant downregulation of Nrf2 in human livers, aged mice, and senescent hepatocytes. This suppression of age-related Nrf2 exacerbates HIRI, as reflected by impaired antioxidant defenses and increased ferroptosis (elevated lipid peroxidation, iron overload, malondialdehyde (MDA) accumulation, glutathione (GSH) depletion and TFR upregulation). Genetic Nrf2 deficiency exacerbates these pathological changes in both cellular and animal models. Notably, treatment with Fer-1 effectively reduced liver damage biomarkers (ALT/AST) and ferroptotic responses in Nrf2-knockout systems. Mechanistically, aging-induced GSK3β overexpression drives Nrf2 dysfunction, establishing a GSK3β-Nrf2-ferroptosis axis involved in IRI progression. Notably, therapeutic targeting of GSK3β by microdose lithium or ferroptosis inhibition by Fer-1 alleviated HIRI in aged mice. CONCLUSIONS:Our study revealed a novel aging-related pathogenesis axis in which GSK3β upregulation drives Nrf2 deficiency-mediated ferroptosis in hepatocytes, thereby exacerbating HIRI. Pharmacological targeting of this pathway may be a promising therapeutic strategy for elderly patients undergoing liver surgery.

BACKGROUND:In diabetic nephropathy (DN), oxidative stress disrupts normal metabolic processes, contributing to progressive kidney injury. Although Nfe2l1 (also known as Nrf1) is known to regulate oxidative stress and metabolism, its specific role in DN remains poorly understood. This study investigated how changes in Nrf1 expression influence DN-associated renal fibrosis. METHODS:Nrf1 function was examined in multiple experimental settings, including: human DN kidney tissues; wild-type and proximal tubule-specific Nfe2l1 knockout mice subjected to high-fat diet plus STZ-induced DN; HK-2 cells exposed to high glucose and palmitic acid; and diabetic mice treated with the Nrf1 activator RUN-47. RESULTS:Nrf1 expression was markedly reduced in kidney tissues from patients with DN, as well as in the renal proximal tubules of DN mice and in high glucose and palmitic acid-treated HK-2 cells. Proximal tubule-specific Nfe2l1 knockout in mice and siRNA-mediated Nfe2l1 knockdown in HK-2 cells both aggravated tubular injury and fibrosis. Transcriptomic profiling indicated that Nrf1 modulates lipid metabolism through the PPARα signaling pathway and that its suppression exacerbates mitochondrial damage and lipid metabolism disorders. Mechanistically, Nrf1 directly binds to the PPARα promoter to transcriptionally activate its expression. Pharmacological inhibition and activation experiments confirmed that Nrf1 exerts its protective effects at least in part via PPARα signaling. Conversely, Nrf1 overexpression in HK-2 cells or pharmacological activation by RUN-47 significantly attenuated tubular damage, fibrotic changes, and lipid metabolism abnormalities. Notably, these protective effects were abrogated in the absence of Nrf1. CONCLUSIONS:Nrf1 downregulation in renal tubules promotes renal fibrosis in DN by impairing PPARα-mediated fatty acid oxidation, inducing mitochondrial dysfunction and lipid accumulation. Mechanistically, Nrf1 directly transcriptionally activates PPARα, and pharmacological activation of Nrf1 attenuates DN progression. These findings identify Nrf1 as a potential therapeutic target for slowing DN progression.

Introduction Nfe2l1 is a transcription factor that is highly conserved and is encoded by the Nuclear Factor Erythroid 2 Like 1 (Nfe2l1) gene, which responds to oxidative stress, proteotoxic stress, and endoplasmic reticulum stress in cells; However, its specific role in the context of acute kidney injury (AKI) is not fully understood. Objectives We were aim to explore the protective effect and mechanism of Nfe2l1 on ferroptosis in cisplatin-induced AKI (CI-AKI), as well as the protective effect of RUN-47, a Nfe2l1 activator, on CI-AKI in vivo and in vitro. Methods We established models of cisplatin-induced nephrotoxicity in vitro and in vivo. Results We observed that Nfe2l1, highly expressed in renal tubular cells, was significantly downregulated following cisplatin treatment. Proximal tubule-specific Nfe2l1 knockout aggravated CI-AKI, whereas Nfe2l1 overexpression attenuated it. RNA sequencing analysis revealed that Nfe2l1 overexpression decreased the number of transcripts involved in ferroptosis, after cisplatin treatment. Furthermore, ferroptosis responses, characterized by increased lipid peroxidation and iron content, along with decreased ferroportin (FPN), XCT, and glutathione peroxidase 4 (GPX4) levels, were mitigated in Nfe2l1-overexpressing HK-2 cells but exacerbated in Nfe2l1-knockout mice and Nfe2l1-knockdown HK-2 cells. Moreover, lipidomic and RNA sequencing indicated that Nfe2l1 regulated polyunsaturated fatty acids (PUFAs) levels and inhibited ACSL4 expression. Additionally, Chromatin immunoprecipitation (ChIP) and dual-luciferase reporter gene assay experiments demonstrated direct binding of Nfe2l1 to the ACSL4 promoter, thereby inhibiting its transcription. Significantly, ACSL4 inhibitors reduced the sensitivity of HK-2 cells to ferroptosis induced by Nfe2l1 knockdown. Finally, RUN-47, a novel Nfe2l1 activator, significantly alleviated CI-AKI in vivo and in vitro . Conclusion These findings identify Nfe2l1 as a novel suppressor of renal tubular ferroptosis by transcriptionally inhibiting ACSL4 expression and thereby reducing PUFA levels. RUN-47 can serve as a potential therapeutic agent for CI-AKI.

BackgroundCisplatin is a widely used drug for the treatment of solid organ cancer, but its renal toxicity cannot be ignored. Amentoflavone (AME), a natural flavonoid compound, has remarkable pharmacological effects, including anti-inflammatory and antioxidative effects. The effect and mechanism of AME on cisplatin-induced acute kidney injury (CI-AKI) remain unclear.MethodsWe investigated the effect of AME on CI-AKI using the HK-2 cell line and C57BL/6 mice. Renal function, tissue damage, and molecular markers were assessed to explore the effects of AME on oxidative stress and cell death pathways.ResultsIn vitro, AME significantly suppressed the cytotoxic effects of cisplatin on HK-2 cells. Furthermore, AME significantly inhibited cisplatin-induced ferroptosis and PANoptosis (apoptosis, pyroptosis and necroptosis). In mice with acute kidney injury induced by a single intraperitoneal injection of cisplatin, the daily administration of AME during AKI effectively improved renal function and alleviated renal tubular injury, characterized by the normalization of blood urea nitrogen (BUN) and serum creatinine (SCr) levels; it also inhibited cisplatin-induced renal ferroptosis and PANoptosis. AME is a natural antioxidant that activates the Nrf2 antioxidant pathway both in vivo and in vitro. In Nrf2 knockout mice and knockdown cells, the protective effect of AME against cisplatin-induced nephrotoxicity disappeared. However, after Nrf2 knockout, the effect of AME on ferroptosis completely disappeared, and that on PANoptosis partially disappeared.ConclusionAmentoflavone has a protective effect on cisplatin-induced acute kidney injury via a mechanism related to the Nrf2-dependent antioxidant pathway and the regulation of ferroptosis and PANoptosis.

Glucocorticoid resistance increases the frequency of acute exacerbations and the risk of death in chronic obstructive pulmonary disease (COPD) patients with a history of long-term heavy smoking. In this study we aimed to investigate the role of neutrophil ferroptosis resistance and the formation of neutrophil extracellular traps (NETs) in cigarette smoke (CS)-induced glucocorticoid resistance in COPD. We collected clinical specimens from COPD patients and healthy subjects. A mouse model of COPD induced by CS exposure was established in vivo. Neutrophils were isolated from the peripheral blood of human donors and exposed to CS extract in vitro. We found extensive NET formation was observed in COPD patients with a history of long-term heavy smoking and was closely related to glucocorticoid resistance. In vivo, we found that prolonged CS exposure promoted NET formation and that rendered dexamethasone (Dex) treatment ineffective at alleviating lung inflammation in COPD model mice. However, the NET degrading agent deoxyribonuclease I could increase sensitivity to Dex in COPD model mice. In vitro experiments demonstrated that CS extract increased neutrophil cell viability by activating the Nrf2/SLC7A11/GPX4 pathway and inducing ferroptosis resistance in neutrophils. And we found that neutrophil specific GPX4 knockout inhibited CS-induced NET formation, increased sensitivity to Dex, and alleviated CS-induced glucocorticoid resistance in vivo and in vitro. In conclusion CS promotes glucocorticoid resistance in COPD by inducing ferroptosis resistance in neutrophils, further resulting in NET formation.

BACKGROUND:The transition from acute kidney injury (AKI) to chronic kidney disease (CKD) is a significant cause of kidney failure. Although the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) has been demonstrated to inhibit ferroptosis and alleviate cisplatin-induced AKI, the specific roles of Nrf2 and the alkaloid leonurine in modulating the AKI-CKD transition remain incompletely elucidated. METHODS:Murine and human proximal tubular epithelial cell models of the AKI-CKD transition were established using repeated low-dose cisplatin (RLDC) to investigate the roles of Nrf2 and leonurine in ferroptosis regulation and disease progression. KEY RESULTS:In mice, RLDC administration induced persistent tubular injury, ferroptosis, and progressive renal fibrosis. In HK-2 cells, RLDC triggered oxidative stress and ferroptosis. Although Nrf2 expression was transiently upregulated during the acute phase (4 weeks post-RLDC), it was downregulated by the chronic phase (8 weeks post-RLDC), correlating with impaired antioxidant capacity and exacerbated ferroptosis. Nrf2 knockout mice exhibited more severe oxidative damage, ferroptosis, and renal dysfunction following RLDC challenge. Pharmacological activation of Nrf2 by leonurine attenuated oxidative injury and ferroptosis and promoted tubular repair. Leonurine also suppressed the epithelial-mesenchymal transition and aberrant extracellular matrix deposition, ultimately mitigating renal fibrosis. The protective effects of leonurine were abolished in Nrf2 knockout mice. CONCLUSION:These findings demonstrate that Nrf2 activation mitigates cisplatin-induced AKI-CKD transition by counteracting oxidative stress and ferroptosis, thereby attenuating renal fibrosis. Leonurine, as a potent Nrf2 activator, represents a promising therapeutic agent for preventing AKI-CKD transition.

BACKGROUND:Fine particulate matter (PM2.5) is a global environmental problem that threatens public health because it can induce ferroptosis and cause lung injury. Hesperetin (Hes), a natural compound widely present in fruits and vegetables, can activate nuclear factor erythroid 2-related factor 2 (Nrf2), thereby exerting powerful antioxidant effects. PURPOSE:We explored the antioxidant effects of Hes on lung injury caused by PM2.5 exposure. METHODS:In vivo, a mouse model of PM2.5-induced lung injury was used to evaluate the protective effect of Hes. In vitro, the effects of Hes on PM2.5-induced ferroptosis were examined in BEAS-2B cells. RESULTS:In vivo, Hes activated the Nrf2 signaling pathway and protected lung tissues from damage induced by PM2.5. In vitro, Hes activated Nrf2 by promoting PI3K/AKT phosphorylation and inhibiting PM2.5-induced ferroptosis. However, in siNrf2-treated BEAS-2B cells, the protective effects of Hes were eliminated. In addition, Nrf2-KO mice exhibited more severe lung injury than did wild-type (WT) mice after PM2.5 exposure. Besides, the protective effects of Hes on PM2.5-exposed Nrf2-KO mice were strongly compromised. CONCLUSION:Hes activates Nrf2 by promoting PI3K/AKT phosphorylation to exert a protective effect on PM2.5-induced ferroptosis and lung injury.

Glucocorticoid resistance increases the frequency of acute exacerbations and the risk of death in chronic obstructive pulmonary disease (COPD) patients with a history of long-term heavy smoking. In this study we aimed to investigate the role of neutrophil ferroptosis resistance and the formation of neutrophil extracellular traps (NETs) in cigarette smoke (CS)-induced glucocorticoid resistance in COPD. We collected clinical specimens from COPD patients and healthy subjects. A mouse model of COPD induced by CS exposure was established in vivo. Neutrophils were isolated from the peripheral blood of human donors and exposed to CS extract in vitro. We found extensive NET formation was observed in COPD patients with a history of long-term heavy smoking and was closely related to glucocorticoid resistance. In vivo, we found that prolonged CS exposure promoted NET formation and that rendered dexamethasone (Dex) treatment ineffective at alleviating lung inflammation in COPD model mice. However, the NET degrading agent deoxyribonuclease I could increase sensitivity to Dex in COPD model mice. In vitro experiments demonstrated that CS extract increased neutrophil cell viability by activating the Nrf2/SLC7A11/GPX4 pathway and inducing ferroptosis resistance in neutrophils. And we found that neutrophil specific GPX4 knockout inhibited CS-induced NET formation, increased sensitivity to Dex, and alleviated CS-induced glucocorticoid resistance in vivo and in vitro. In conclusion CS promotes glucocorticoid resistance in COPD by inducing ferroptosis resistance in neutrophils, further resulting in NET formation.

BACKGROUND:Dihydromyricetin (DHM), a flavonoid primarily sourced from Ampelopsis grossedentata, exhibits anti-inflammatory and antioxidant biological activities. However, the therapeutic effects and the precise underlying mechanism of DHM in chronic obstructive pulmonary disease (COPD) are poorly understood. PURPOSE:Our study aimed to investigate the effects of DHM on COPD and the underlying mechanism. METHODS:In vitro, Beas-2b cells were treated with cigarette smoke extract (CSE) for 24 h. In vivo, BALB/c mice were exposed to cigarette smoke (CS)/ lipopolysaccharide (LPS) for 4 weeks to establish mouse models of COPD. RESULTS:DHM reversed the decreased cell viability, lipid peroxidation, and the downregulated expression of xCT and GPx4 in CSE-treated cells. Moreover, DHM suppressed the CSE-induced GSDMD-mediated pyroptosis activated by the NLPR3 inflammasome and the nonclassical caspase-4 inflammasome. Moreover, DHM improved membrane destruction, mitochondrial damage and pyrogenic corpuscle formation caused by CSE. However, xCT knockdown strongly attenuated the inhibitory effects of DHM on CSE-induced cell death, lipid peroxidation and pyroptosis. Furthermore, we demonstrated that DHM protected against CSE-induced pyroptosis by inhibiting lipid peroxidation triggered by ubiquitination-mediated xCT degradation. In vivo experiments demonstrated that DHM significantly attenuated inflammatory cells infiltration and pro-inflammatory factors secretion in BALF of COPD mice, relieved airway wall thickening and alveolar structural damage, concurrently reducing airway resistance while suppressing lipid peroxidation and pyroptosis in lung tissues of COPD mice. However, conditional knockdown of xCT in mouse lung epithelial cells abolished the protective effects of DHM against COPD, as evidenced by the failure to attenuate inflammatory cell infiltration and cytokine secretion in BALF, to alleviate pathological changes such as pulmonary interstitial thickening, and to suppress pyroptosis pathway activation. CONCLUSION:Our findings uncovered a novel therapeutic mechanism of DHM in COPD, demonstrating its ability to mitigate disease progression by targeting xCT-dependent lipid peroxidation and pyroptosis. This study provides a strong rationale for developing DHM as a clinically viable treatment for COPD.

Nrf1 is a transcription factor that is highly conserved and reacts to oxidative, proteotoxic and endoplasmic reticulum stress in cells; nonetheless, its function in the context of acute kidney injury (AKI) remains unclear. Using a model of cisplatin-induced nephrotoxicity in vitro and in vivo, we found that the expression of Nrf1, which is expressed at high levels in renal tubular cells, was significantly downregulated after cisplatin treatment. Proximal tubule-specific Nrf1 knockout worsened and Nrf1 overexpression attenuated cisplatin-induced (CI)-AKI. RNA sequencing analysis revealed that Nrf1 overexpression decreased the number of transcripts involved in cell death, specifically those associated with ferroptosis, after cisplatin treatment. Furthermore, ferroptosis responses, characterized by increased lipid peroxidation and iron content and decreased FPN, XCT and glutathione peroxidase 4 levels, were attenuated in Nrf1-overexpressing HK-2 cells but worsened in Nrf1-knockout mice and Nrf1-knockdown HK-2 cells. Moreover, lipidomic and RNA sequencing results indicated that Nrf1 regulated the levels of polyunsaturated fatty acids (PUFAs) and inhibited the expression of ACSL4. Additionally, ChIP experiments revealed that Nrf1 bound to the promoter region of ACSL4, thereby inhibiting its transcription. Furthermore, inhibitors of ACSL4 significantly reduced the sensitivity of HK-2 cells to ferroptosis induced by Nrf1 knockdown. Collectively, these findings suggest that Nrf1 is a novel target for inhibiting ferroptosis in renal tubule cells by suppressing the transcription and expression of ACSL4, thereby reducing PUFA levels. Consequently, activators developed for Nrf1 may hold therapeutic potential in the treatment of patients with CI-AKI.

AIMS:Ovarian cancer (OC) is a common malignant tumor with the greatest mortality rate among gynecological tumors. Tiliroside (TIL) is a glycosidic dietary flavonoid with various pharmacological activities. The purpose of this study was to investigate the exact mechanism by which TIL eliminates OC cells. METHODS/KEY FINDINGS:In vitro, TIL exerted anti-tumor activities by inducing cell death and inhibiting the invasion and migration of A2780 and OVCAR8 cells. Additionally, the suppressive effect of TIL on OC cells was mainly due to the induction of ferroptosis, as demonstrated by the fact that only ferroprostatin-1 (Fer-1) significantly inhibited the anti-tumor activity of TIL, with the accumulation of ROS, MDA, and Fe2+ and a reduction in GPX4 expression. SwissTargetPrediction, molecular docking and CETSA assay showed that the direct interaction between AKR1B1 and TIL decreased its stability and expression. Notably, AKR1B1 overexpression significantly attenuated the effects of TIL on the proliferation, invasion, migration and ferroptosis on OC cells, whereas the levels of Fe2+ remained unaffected. Interestingly, the results of the RNA sequencing (RNA-seq) analysis suggested that the regulation of iron homeostasis by TIL might be connected to ion transport. Western blotting and immunofluorescence confirmed that TIL could modulate iron metabolism by regulating iron ion transport and ferritinophagy, ultimately resulting in ferroptosis. In xenograft model mice, TIL treatment inhibited tumor growth without causing substantial tissue damage. SIGNIFICANCE:Our research revealed that TIL simultaneously targets AKR1B1 and modulates iron metabolism, thereby inducing ferroptosis and improving anti-tumor efficacy. As a novel drug, TIL is promising for OC treatment.

Ferroptosis plays a key role in cisplatin-induced acute kidney injury (AKI). Bergenin, which is extracted from Ardisiae Japonicae Herba and has long been used in folk tea and herbal tea drinks, is known to activate Nrf2 and has anti-inflammatory and antioxidant properties, however, its protective influence on CI-AKI has not been elucidated. We used models of cisplatin-induced nephrotoxicity in vitro and CI-AKI models in vivo. In vitro, we found that ferroptosis and ferritinophagy biomarkers were strongly regulated by bergenin treatment. Mechanistic experiments demonstrated that bergenin bound to and phosphorylated GSK3(3, which inhibited its activity, to promote the nuclear translocation of Nrf2 and its subsequent binding to the PPAR gamma promoter sequence to activate PPAR gamma. However, the protective effects of bergenin on ferroptosis and ferritinophagy in cisplatin-exposed HK-2 cells were diminished when Nrf2 or PPAR gamma was inhibited. In vivo, bergenin effectively inhibited renal damage induced by cisplatin. Furthermore, bergenin attenuated ferritinophagy-mediated ferroptosis caused by cisplatin; these effects were abolished in Nrf2 knockout mice. Our findings revealed that bergenin effectively protected against ferritinophagy and ferroptosis in CI-AKI, which was largely dependent on the activation of the p-GSK3(3/ Nrf2/PPAR gamma pathway.

Ferroptosis plays a key role in cisplatin-induced acute kidney injury (AKI). Bergenin, which is extracted from Ardisiae Japonicae Herba and has long been used in folk tea and herbal tea drinks, is known to activate Nrf2 and has anti-inflammatory and antioxidant properties, however, its protective influence on CI-AKI has not been elucidated. We used models of cisplatin-induced nephrotoxicity in vitro and CI-AKI models in vivo. In vitro, we found that ferroptosis and ferritinophagy biomarkers were strongly regulated by bergenin treatment. Mechanistic experiments demonstrated that bergenin bound to and phosphorylated GSK3β, which inhibited its activity, to promote the nuclear translocation of Nrf2 and its subsequent binding to the PPARγ promoter sequence to activate PPARγ. However, the protective effects of bergenin on ferroptosis and ferritinophagy in cisplatin-exposed HK-2 cells were diminished when Nrf2 or PPARγ was inhibited. In vivo, bergenin effectively inhibited renal damage induced by cisplatin. Furthermore, bergenin attenuated ferritinophagy-mediated ferroptosis caused by cisplatin; these effects were abolished in Nrf2 knockout mice. Our findings revealed that bergenin effectively protected against ferritinophagy and ferroptosis in CI-AKI, which was largely dependent on the activation of the p-GSK3β/Nrf2/PPARγ pathway.

Liver fibrosis is an increasingly serious global health issue, and an effective treatment strategy is to inhibit the activation of hepatic stellate cells (HSCs). The role of daphnetin (Daph), which is a natural coumarin derivative isolated from plants of the genus Daphne, in the treatment of hepatic fibrosis is still unclear. Mice were treated with carbon tetrachloride (CCl4), and the inhibitory effect of Daph on hepatic fibrosis was evaluated. In vitro, the effect of Daph on the activated human HSCs line LX-2 was studied. In vivo, Daph alleviated collagen accumulation and reduced the expression of fibrotic genes. However, these changes were reversed with ferrostatin-1 (Fer-1). In vitro, Daph induced ferroptosis in LX-2 cells, which was characterized by increased lipid peroxidation and iron accumulation. However, deferoxamine (DFO) and Fer-1 partially abrogated the antifibrotic effect of Daph. Mechanically, Daph exerted an antifibrotic effect by ubiquitinating glutathione peroxidase 4 (GPX4) and stimulating ferritinophagy-mediated ferroptosis in HSCs. These results indicated that Daph promoted the ubiquitination of GPX4 and ferritinophagy-mediated ferroptosis in HSCs, which could provide new clues for further pharmacological research on the antifibrotic effect of Daph.

Background and Purpose: Mitochondrial dysfunction is essential in renal tubular damage, and mitophagy, a selective form of autophagy, specifically eliminates damaged mitochondria. Mitophagy reportedly protects against diabetic kidney disease, cisplatin-induced acute kidney injury (AKI) and other related kidney diseases, but the specific mechanism by which mitophagy protects against cisplatin-induced chronic kidney disease (CKD) remains unclear. Experimental Approach: The effects of farrerol on cisplatin-induced AKI in mice were investigated. C57BL/6 wild-type and Nrf2 knockout mice were used to evaluate the protective effect of farrerol on cisplatin-induced CKD. Key Results: we confirmed that Nrf2- and PINK1/Parkin-mediated mitophagy was significantly increased on the 3rd day of cisplatin stimulation but was reduced on the 38th day of cisplatin stimulation. Similar to previous results, farrerol, a natural compound, also activated Nrf2 on the 38th day of cisplatin administration, subsequently stimulating the Nrf2-targeted antioxidant enzymes HO-1 and NQO1. In addition, farrerol triggered PINK1/Parkin-mediated mitophagy by recruiting the receptor proteins LC3 and p62/SQSTM1, thereby eliminating damaged mitochondria. Furthermore, genetic deletion of Nrf2 reduced PINK1/Parkin-mediated mitophagy activation and led to increased renal tubular necrosis and renal fibrosis. We also found that farrerol alleviated inflammation and renal fibrosis by inhibiting p-NF-κB/NLRP3 and TGF-β/Smad signaling. Conclusions: These data indicated that farrerol effectively inhibited cisplatin-induced inflammation and renal fibrosis by activating Nrf2 and PINK1/Parkin-mediated mitophagy, which provides a potential novel therapeutic target for CKD.

Accumulating evidence suggests that exposure to ambient airborne PM2.5 increases the risk of primary ovarian insufficiency (POI). However, whether ferroptosis, a newly discovered type of cell death involved in PM2.5-induced lung injury and fibrosis, is involved in PM2.5-induced POI has not been determined. This study aimed to verify the involvement of PM2.5-induced ferroptosis in ovarian dysfunction and further demonstrate that melatonin inhibits ferroptosis by activating the Nrf2 signaling pathway to ameliorate POI in vivo and in vitro. In our study, PM2.5 promoted iron accumulation and induced lipid peroxidation, thus contributing to ferroptosis in KGN cells and ovaries. However, these effects were eliminated and enhanced in Nrf2-overexpressing and Nrf2-knockdown cells, respectively. In addition, melatonin and ferrostatin-1 (Fer-1) inhibited ferroptosis by activating the NRF2 signaling pathway, as evidenced by the silencing of Nrf2 in vivo and in vitro. Mechanistically, Nrf2-knockout mice were more susceptible to ferroptosis and PM2.5-induced POI than control mice. Moreover, melatonin suppressed changes in morphological and biochemical indicators related to ferroptosis, such as MDA and GSH depletion and GPX4 and XCT downregulation, by enhancing Nrf2 signaling. Here, we first reported that PM2.5 triggered ferroptosis by increasing ROS levels, lipid peroxidation and glutathione depletion. Notably, melatonin significantly decreased ferroptosis levels and improved ovarian function by activating the NRF2 signaling pathway in vivo and in vitro.

Background: Pyroptosis is an inflammatory form of regulated necrosis that has been implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). However, the role of lipid peroxidation in pyroptosis and its underlying mechanisms in COPD remain unclear. Methods: In vitro, human bronchial epithelial cells (Beas-2b cells) were exposed to cigarette smoke extract (CSE) for 24 h. In vivo, mice were exposed to cigarette smoke (CS) for 4 weeks. To investigate the role of xCT, we used siRNA and AAV6 to conditionally knock down xCT in vitro and in vivo, respectively. Results: The administration of ferrostatin-1 (Fer-1), a ferroptosis inhibitor that inhibits lipid peroxidation, significantly reduced the cytotoxicity of CSE to Beas-2b cells and mitigated inflammatory exudation, lung injury and mucus hypersecretion in mice with CS-induced COPD. Fer-1 suppressed gasdermin D (GSDMD)-mediated pyroptosis caused by CS in vitro and in vivo. However, in Beas-2b cells and the lung epithelial cells of mice, conditional knockdown of xCT (a negative regulatory factor of lipid peroxidation) inhibited the xCT/GPx4 axis, leading to more severe lipid peroxidation and GSDMD-mediated pyroptosis during cigarette smoke exposure. Moreover, we found that CS promoted the degradation of xCT through the ubiquitin proteasome system (UPS) and that treatment with MG132 significantly inhibited the degradation of xCT and downregulated the expression of pyroptosis-related proteins. Conclusion: The results of this study suggested that the ubiquitination-mediated degradation of xCT drives GSDMD-mediated pyroptosis in COPD and is a potential therapeutic target for COPD.