Activation of Nrf2 signalling pathway by tectoridin protects against ferroptosis in particulate matter-induced lung injury

Ferric ammonium citrate regulates iron death in mature porcine oocytes and their embryonic development in vitro through the NRF2 signaling pathway

Iron death is a novel type of programmed cell death caused by excessive accumulation of iron-dependent lipid peroxidation products; however, the function of iron death during porcine oocyte maturation and embryo growth is poorly understood. This study was conducted to investigate the mechanism of ferric ammonium citrate (FAC) in regulating iron death in mature oocytes in vitro through the NRF2 signaling pathway, and subsequent embryonic development. The experiment was divided into four groups: 0 (control group), 2, 5, and 10 μM FAC. Western blotting (WB), reactive oxygen species (ROS)assays, mitochondrial membrane potential (MMP) assays, and Quantitative real-time polymerase chain reaction (qRT-PCR) were used to detect the maturation of porcine oocytes in vitro, the protein content of nuclear transcription factor E2-related factor 2 (Nrf2), the distribution of mitochondria, the level of oxidative stress, and the development of embryos fertilized in vitro. The results showed that with increasing FAC concentrations, the oocyte maturation rate in vitro, Nrf2 protein content, MMP, and cleavage rates of in vitro fertilized embryos decreased (significantly in the 5 μM group); the oxidative stress level was significantly increased; the transcript levels of Nrf2, GPX4, and FTH1 mRNAs were significantly decreased; the expression of ACSL4 was significantly upregulated (P < 0.05); and the blastocyst rate of embryos fertilized in vitro was reduced (significantly in the 2 μM group). In conclusion, FAC can regulate Nrf2 protein levels in porcine oocytes matured in vitro to induce iron death, affecting the maturation rate of oocytes, distribution of mitochondria, level of oxidative stress, expression of iron-death-related genes, and development of embryos after in vitro fertilization.

Ferroptosis is involved in the damage of ocular lens under long-term PM2.5 exposure in rat models and humans

Epidemiological studies show a positive association between air pollution and age-related cataracts, but the pathogenic mechanism remains unclear. This study first demonstrates that fine particulate matter (PM2.5) induces ferroptosis in the lens, leading to morphological and functional disorders, through human, animal, and cellular samples. In 3-week PM2.5-exposed rat models (10 µl 1 mg/ml PM2.5 suspension per eye, 4 times a day), we find that many vacuoles form in the lens equatorial region by analysis of haematoxylin and eosin staining after PM2.5 exposure. Using iron and glutathione (GSH) assay kits, we found increased Fe2+ contents and decreased GSH levels in PM2.5-exposed rats' lenses. Additionally, the lipid peroxide 4-hydroxynonenal (4-HNE) was also found to be elevated with immunoblot, suggesting ferroptosis is involved. Ferroptosis was also observed in human lens epithelial cells treated with 25, 50, and 100 µg/ml PM2.5 suspension for 24 h, accompanied by decreased cell viability and migration. Furthermore, we collect about 60 human lens anterior capsule (HLAC) samples for RNA-seq. The results show that compared to HLACs from areas with PM2.5 concentration ≤30 μg/m³, ferroptosis-related genes expression of those from areas with PM2.5 concentration ≥35 μg/m³ are significantly altered, such as glutathione peroxidase 4 and STEAP family member 3. Also, human lens in areas with high PM2.5 concentrations showed elevated levels of transferrin receptor and 4-HNE with immunoblot, and down-regulated expression of connexin 43 (Cx43) through immunofluorescent. These results demonstrate that ferroptosis plays a key role in PM2.5-induced cataractogenesis.

Redox cell signalling triggered by black carbon and/or radiofrequency electromagnetic fields: Influence on cell death

The capacity of environmental pollutants to generate oxidative stress is known to affect the development and progression of chronic diseases. This scientific review identifies previously published experimental studies using preclinical models of exposure to environmental stress agents, such as black carbon and/or RF-EMF, which produce cellular oxidative damage and can lead to different types of cell death. We summarize in vivo and in vitro studies, which are grouped according to the mechanisms and pathways of redox activation triggered by exposure to BC and/or EMF and leading to apoptosis, necrosis, necroptosis, pyroptosis, autophagy, ferroptosis and cuproptosis. The possible mechanisms are considered in relation to the organ, cell type and cellular-subcellular interaction with the oxidative toxicity caused by BC and/or EMF at the molecular level. The actions of these environmental pollutants, which affect everyday life, are considered separately and together in experimental preclinical models. However, for overall interpretation of the data, toxicological studies must first be conducted in humans, to enable possible risks to human health to be established in relation to the progression of chronic diseases. Further actions should take pollution levels into account, focusing on the most vulnerable populations and future generations.

New insights into crosstalk between Nrf2 pathway and ferroptosis in lung disease

Ferroptosis is a distinctive process of cellular demise that is linked to amino acid metabolism, lipid oxidation, and iron oxidation. The ferroptosis cascade genes, which are closely associated with the onset of lung diseases, are among the regulatory targets of nuclear factor erythroid 2-related factor 2 (Nrf2). Although the regulation of ferroptosis is mostly mediated by Nrf2, the precise roles and underlying regulatory mechanisms of ferroptosis and Nrf2 in lung illness remain unclear. This review provides new insights from recent discoveries involving the modulation of Nrf2 and ferroptosis in a range of lung diseases. It also systematically describes regulatory mechanisms involving lipid peroxidation, intracellular antioxidant levels, ubiquitination of Nrf2, and expression of FSP1 and GPX4. Finally, it summarises active ingredients and drugs with potential for the treatment of lung diseases. With the overarching aim of expediting improvements in treatment, this review provides a reference for novel therapeutic mechanisms and offers suggestions for the development of new medications for a variety of lung disorders.

Particulate matter-induced epigenetic modifications and lung complications

Air pollution is one of the leading causes of early deaths worldwide, with particulate matter (PM) as an emerging factor contributing to this trend. PM is classified based on its physical size, which ranges from PM10 (diameter ≤10 μm) to PM2.5 (≤2.5 μm) and PM0.5 (≤0.5 μm). Smaller-sized PM can move freely through the air and readily infiltrate deep into the lungs, intensifying existing health issues and exacerbating complications. Lung complications are the most common issues arising from PM exposure due to the primary site of deposition in the respiratory system. Conditions such as asthma, COPD, idiopathic pulmonary fibrosis, lung cancer and various lung infections are all susceptible to worsening due to PM exposure. PM can epigenetically modify specific target sites, further complicating its impact on these conditions. Understanding these epigenetic mechanisms holds promise for addressing these complications in cases of PM exposure. This involves studying the effect of PM on different gene expressions and regulation through epigenetic modifications, including DNA methylation, histone modifications and microRNAs. Targeting and manipulating these epigenetic modifications and their mechanisms could be promising strategies for future treatments of lung complications. This review mainly focuses on different epigenetic modifications due to PM2.5 exposure in the various lung complications mentioned above.

FGF10 protects against particulate matter-induced lung injury by inhibiting ferroptosis via Nrf2-dependent signaling

Particulate matter (PM) is considered the fundamental component of atmospheric pollutants and is associated with the pathogenesis of many respiratory diseases. Fibroblast growth factor 10 (FGF10) mediates mesenchymal-epithelial signaling and has been linked with the repair process of PM-induced lung injury (PMLI). However, the pathogenic mechanism of PMLI and the specific FGF10 protective mechanism against this injury are still undetermined. PM was administered in vivo into murine airways or in vitro to human bronchial epithelial cells (HBECs), and the inflammatory response and ferroptosis-related proteins SLC7A11 and GPX4 were assessed. The present research investigates the FGF10-mediated regulation of ferroptosis in PMLI mice models in vivo and HBECs in vitro. The results showed that FGF10 pretreatment reduced PM-mediated oxidative damage and ferroptosis in vivo and in vitro. Furthermore, FGF10 pretreatment led to reduced oxidative stress, decreased secretion of inflammatory mediators, and activation of the Nrf2-dependent antioxidant signaling. Additionally, silencing of Nrf2 using siRNA in the context of FGF10 treatment attenuated the effect on ferroptosis. Altogether, both in vivo and in vitro assessments confirmed that FGF10 protects against PMLI by inhibiting ferroptosis via the Nrf2 signaling. Thus, FGF10 can be used as a novel ferroptosis suppressor and a potential treatment target in PMLI.

Tectoridin inhibits the growth of bladder cancer by regulating PI3K/MAPK pathway through RAB27B

Bladder cancer (BC) is a common and malignant tumor of the urinary tract, and its treatment options are limited. Tectoridin (TEC) has antitumor activity against prostate and colon cancer, but its effects on BC are poorly understood. BC cells were treated with increasing concentrations of TEC, and its effects on cell proliferation, migration, invasiveness, and apoptosis were assessed. Xenograft mouse model was used to evaluate the influences of TEC on BC tumor growth. Western blot analysis was conducted to explore the downstream pathways affected by TEC. TEC treatment decreased BC cell viability in a dose-dependent manner (IC50 ≈ 25 μM), and inhibited cell proliferation, migration, and invasiveness while promoting apoptosis. Clinical analysis revealed high expression of RAB27B in BC tumor tissues, particularly in advanced stages, correlating with an unfavorable prognosis. In vitro experiments demonstrated that TEC suppressed the PI3K/MAPK pathway by targeting RAB27B, and overexpression of RAB27B counteracted the antitumor effects of TEC. In xenograft models, TEC administration suppressed tumor growth, reduced tumor volume, inhibited cell proliferation, and suppressed the PI3K/MAPK pathway, highlighting its potential as an inhibitor of tumor growth. TEC suppresses BC tumor growth by targeting RAB27B and inactivating the PI3K/MAPK signaling and may provide a promising therapeutic target for BC treatment.

Polystyrene microplastics induce pulmonary fibrosis by promoting alveolar epithelial cell ferroptosis through cGAS/STING signaling

Polystyrene microplastics (PS-MPs) are new types of environmental pollutant that have garnered significant attention in recent years since they were found to cause damage to the human respiratory system when they are inhaled. The pulmonary fibrosis is one of the serious consequences of PS-MPs inhalation. However, the impact and underlying mechanisms of PS-MPs on pulmonary fibrosis are not clear. In this study, we studied the potential lung toxicity and PS-MPs-developed pulmonary fibrosis by long-term intranasal inhalation of PS-MPs. The results showed that after exposing to the PS-MPs, the lungs of model mouse had different levels of damage and fibrosis. Meanwhile, exposing to the PS-MPs resulted in a markedly decrease in glutathione (GSH), an increase in malondialdehyde (MDA), and iron overload in the lung tissue of mice and alveolar epithelial cells (AECs). These findings suggested the occurrence of PS-MP-induced ferroptosis. Inhibitor of ferroptosis (Fer-1) had alleviated the PS-MPs-induced ferroptosis. Mechanically, PS-MPs triggered cell ferroptosis and promoted the development of pulmonary fibrosis via activating the cGAS/STING signaling pathway. Inhibition of cGAS/STING with G150/H151 attenuated pulmonary fibrosis after PS-MPs exposure. Together, these data provided novel mechanistic insights of PS-MPs-induced pulmonary fibrosis and a potential therapeutic paradigm.

Molybdenum and cadmium co-induce apoptosis and ferroptosis through inhibiting Nrf2 signaling pathway in duck (Anas platyrhyncha) testes

Cadmium (Cd) and high molybdenum (Mo) are injurious to the body. Previous research has substantiated that Cd and Mo exposure caused testicular injury of ducks, but concrete mechanism is not fully clarified. To further survey the toxicity of co-exposure to Cd and Mo in testis, 40 healthy 8-day-old Shaoxing ducks (Anas platyrhyncha) were stochasticly distributed to 4 groups and raised with basic diet embracing Cd (4 mg/kg Cd) or Mo (100 mg/kg Mo) or both. At the 16th wk, testis tissues were gathered. The characteristic ultrastructural changes related to apoptosis and ferroptosis were observed in Mo or Cd or both groups. Besides, Mo or Cd or both repressed nuclear factor erythroid 2-related factor 2 (Nrf2) pathway via decreasing Nrf2, Heme oxygenase-1 (HO-1), NAD(P)H quinone oxidoreductase 1 (NQO1), Glutamate-cysteine ligase catalytic subunit (GCLC) and Glutamate-cysteine ligase modifier subunit (GCLM) mRNA expression of and Nrf2 protein expression, then stimulated apoptosis by elevating Bcl-2 antagonist/killer-1 (Bak-1), Bcl-2-associated X-protein (Bax), Cytochrome complex (Cyt-C), caspase-3 mRNA expression, cleaved-caspase-3 protein expression and apoptosis rate, as well as reducing B-cell lymphoma-2 (Bcl-2) mRNA expression and ratio of Bcl-2 to Bax, and triggered ferroptosis by upregulating Acyl-CoA Synthetase Long Chain Family Member 4 (ACSL4), transferrin receptor (TFR1) and Prostaglandin-Endoperoxide Synthase 2 (PTGS2) expression levels, and downregulating ferritin heavy chain 1 (FTH1), ferritin light chain 1 (FTL1), ferroportin 1 (FPN1), solute carrier family 7 member 11 (SCL7A11) and glutathione peroxidase 4 (GPX4) expression levels. The most obvious changes of these indexes were observed in co-treated group. Altogether, the results announced that Mo or Cd or both evoked apoptosis and ferroptosis by inhibiting Nrf2 pathway in the testis of ducks, and co-exposure to Mo and Cd exacerbated these variations.

Recent advances in the potential effects of natural products from traditional Chinese medicine against respiratory diseases targeting ferroptosis

Respiratory diseases, marked by structural changes in the airways and lung tissues, can lead to reduced respiratory function and, in severe cases, respiratory failure. The side effects of current treatments, such as hormone therapy, drugs, and radiotherapy, highlight the need for new therapeutic strategies. Traditional Chinese Medicine (TCM) offers a promising alternative, leveraging its ability to target multiple pathways and mechanisms. Active compounds from Chinese herbs and other natural sources exhibit anti-inflammatory, antioxidant, antitumor, and immunomodulatory effects, making them valuable in preventing and treating respiratory conditions. Ferroptosis, a unique form of programmed cell death (PCD) distinct from apoptosis, necrosis, and others, has emerged as a key area of interest. However, comprehensive reviews on how natural products influence ferroptosis in respiratory diseases are lacking. This review will explore the therapeutic potential and mechanisms of natural products from TCM in modulating ferroptosis for respiratory diseases like acute lung injury (ALI), asthma, pulmonary fibrosis (PF), chronic obstructive pulmonary disease (COPD), lung ischemia-reperfusion injury (LIRI), pulmonary hypertension (PH), and lung cancer, aiming to provide new insights for research and clinical application in TCM for respiratory health.

Tectorigenin inhibits oxidative stress by activating the Keap1/Nrf2/HO-1 signaling pathway in Th2-mediated allergic asthmatic mice

Asthma is a chronic obstructive airway condition and one of the most common non-communicable illnesses worldwide. Tectorigenin (Tec) is an isoflavonoid found in plants that possesses significant antioxidative and anti-inflammatory abilities. Nevertheless, the antioxidative properties of Tec have not yet been documented in allergic asthma. In this study, we created an asthmatic BALB/c mouse model induced by ovalbumin (OVA) and used it to assess the efficacy of Tec as a possible therapy agent. Tec decreased the serum OVA-specific immunoglobulin (Ig) E and IgG1 secretion levels. The total number of cells and the distribution of inflammatory cells decreased significantly in bronchoalveolar lavage fluid (BALF), with weakened inflammatory reaction in pulmonary tissues. Additionally, Tec regulated the T helper 1(Th1)/Th2 balance by increasing the expression of Th1- related factors (interleukin (IL)-12 and T-bet) and decreasing the expression of Th2-related factors (IL-4, IL-5, IL-13, and GATA binding protein 3. In addition, the pro-inflammatory cytokines such as IL-6, tumor necrosis factor-alpha, and IL-1β were also inhibited by Tec. Tec also dramatically increased antioxidant (catalase and superoxide dismutase) concentrations while lowering the intensity of the indicators of oxidative stress such as reactive oxygen species and malondialdehyde in BALF. Finally, Tec effectively activated the Keap1/Nrf2/HO-1 signaling pathway and prevented the epithelial-mesenchymal transition. The results of the current study show that Tec may be useful in relieving the inflammatory and oxidative stress responses associated with asthma.

Fraxetin alleviates BLM-induced idiopathic pulmonary fibrosis by inhibiting NCOA4-mediated epithelial cell ferroptosis

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) is a debilitating lung condition with few available treatments. The early driver of wound repair that contributes to IPF has been extensively identified as repetitive alveolar epithelial damage. According to recent reports, IPF is linked to ferroptosis, a unique type of cell death characterized by a fatal buildup of iron and lipid peroxidation.

OBJECTIVE AND METHOD

There is little information on epithelial cells that induce pulmonary fibrosis by going through ferroptosis. In this study, we used bleomycin (BLM) to examine the impact of ferroptosis on IPF in mouse lung epithelial cells (MLE-12).

RESULTS

We discovered that BLM increases ferroptosis in MLE-12. Additionally, we found that NCOA4 is overexpressed and plays a key role in the ferroptosis of epithelial cells throughout the IPF process. Using Molecular docking, we found that Fraxetin, a natural component extracted from Fraxinus rhynchophylla, formed a stable binding to NCOA4. In vitro investigations showed that Fraxetin administration greatly decreased ferroptosis and NCOA4 expression, which in turn lowered the release of inflammatory cytokines.

CONCLUSION

Fraxetin treatment significantly alleviated BLM-induced lung inflammation and fibrosis. Our findings imply that fraxetin possesses inhibitory roles in ferroptosis and can be a potential drug against IPF.