PM2.5 induces ferroptosis in human endothelial cells through iron overload and redox imbalance

Green tea enriched with catechins prevents particulate matter2.5 exposure-induced cardiovascular cytotoxicity via regulation of ferroptosis in BALB/c mice

This study was conducted to assess the protective effects of the aqueous green tea extract (GTE) against particulate matter (PM)2.5-induced cardiac dysfunction in BALB/c mice. The GTE treatment ameliorated PM2.5-induced ferroptosis and vascular smooth muscle cells (VSMC) switching in cardiovascular A7r5 cells. The administration of GTE regulated the body weight change, heart index, serum biomarkers, and cardiac antioxidant system. GTE downregulated the inflammatory reaction by inhibiting the protein expression levels of TLR2, TLR4, NOX4, p-Akt, p-JNK, p-IκB-α, Cas-1, iNOS, Ptgs2, HO-1, TNF-α, and IL-1β. In addition, the supplement of GTE ameliorated cardiac damage by regulating the ferroptotic biomarkers such as p53, xCT, GPX4, TFR, and FtH, and mitochondrial apoptosis indicators such as Cas-3, BCl-2, and BAX. It also protected VSMC phenotype levels of SM22α, αSMA, and calponin. This study suggests that GTE might be a potential material to protect PM2.5-induced cardiac damage via ferroptosis and inflammation pathway.

Ambient fine particulate matter induces cardiac fibrosis through triggering ferroptosis by heme degradation induced-iron overload

BACKGROUND

Previous studies have shown a significant correlation between exposure to ambient fine particulate matter (PM2.5) and cardiac fibrosis, yet the precise detrimental effects and underlying mechanisms of PM2.5 exposure on cardiac fibrosis remain incompletely understood. Cardiac remodeling, a process involving ferroptosis that can be initiated by iron overload, has been implicated in this phenomenon. In this study, we sought to explore the potential mechanism by which ferroptosis contributes to PM2.5-induced cardiac fibrosis.

METHODS AND RESULTS

Male C57BL/6 J mice were exposed to ambient PM2.5 by intratracheal instillation twice a week for 12 weeks to establish PM2.5-exposed murine models and cardiomyocytes were used to verify the role of ferroptosis in PM2.5-induced cardiac fibrosis. In this study, it was observed that exposure to PM2.5 resulted in cardiac fibrosis and a significant upregulation of cardiac fibrosis-related markers (TGF-β1, collagen-I and p-Smad3), heme oxygenase 1 (HO-1), and ACSL4 (a biomarker for ferroptosis). Additionally, PM2.5 exposure led to a decrease in heme content, iron overload, increased levels of the lipid peroxidation marker 4-HNE, and a reduction in the ratio of GSH/GSSG and GPX4 (a biomarker for ferroptosis) in murine hearts. Significantly, the use of ferrostatin-1 (an inhibitor of ferroptosis) mitigated PM2.5-induced cardiac fibrosis and decreased the levels of cardiac fibrosis-related markers (TGF-β1, collagen-I and p-Smad3) in murine hearts, indicating the essential role of ferroptosis in the development of cardiac fibrosis. In vitro experiments showed that PM2.5 upregulated the expression of HO-1 protein, promoted iron accumulation, increased 4-HNE levels, and triggered ferroptosis in cardiomyocytes. The inhibition of HO-1 (zinc protoporphyrin 9) and siRNA HO-1 effectively mitigated PM2.5-induced iron overload, ferroptosis, and heme accumulation in cardiomyocytes. Additionally, treatment with ferrostatin-1 markedly decreased the expression levels of cardiac fibrosis-related markers, such as TGF-β1 and p-Smad3.

CONCLUSION

Collectively, our study showed that the activation of ferroptosis/TGF-β1/Smad3 signaling pathway, initiated by heme degradation-induced iron overload in cardiomyocytes, serves as a mechanism in murine models of PM2.5-induced cardiac fibrosis.

Cryptotanshinone alleviates cerebral ischemia reperfusion injury by regulating ferroptosis through the PI3K/AKT/Nrf2 and SLC7A11/GPX4 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The Cryptotanshinone (CT) is a kind of Chinese medicine extracted from salvia miltiorrhiza, which has various pharmacological activities and is widely used in the treatment of diseases.

AIM OF THE STUDY

The objective is to delve into the mechanism by which cryptotanshinone (CT) exerts its effects on rats with the middle cerebral artery occlusion/reperfusion (MCAO/R) model. Additionally, it aims to further assess the interplay between inflammation and oxidative stress, along with the underlying mechanism of CT's anti-ferroptosis function.

MATERIALS AND METHODS

We constructed the middle cerebral artery occlusion/reperfusion (MCAO/R) model in rats. The effects of cryptotanshinone (CT) were evaluated using 2,3,5 - triphenyltetrazolium chloride (TTC) staining, behavioral assays, immunofluorescence, hematoxylin - eosin (HE) staining, and Nissl staining. Additionally, in vitro, cell viability was assessed by the Cell Counting Kit - 8 (CCK - 8) assay following experimental dosing. Oxygen - glucose deprivation/oxidation (OGD/R) models were established in PC12 and BV2 cells. Flow cytometry was employed to detect cellular reactive oxygen species (ROS) expression. The activities of superoxide dismutase (SOD), malondialdehyde (MDA), glutathione peroxidase (GSH-px), and Mitochondrial Membrane Potential Assay Kit with JC-1(JC-1) were measured using biochemical methods. Inflammatory factor levels were determined using enzyme-linked immunosorbent assay (ELISA) kits. Immunoblotting was used to detect the levels of rat phosphatidylinositol 3 - kinase (PI3K), phosphorylated-PI3K (P-PI3K), protein kinase B (AKT), phosphorylated - AKT (P-AKT), nuclear factor erythroid 2 - related factor 2 (Nrf2), solute carrier family 7 member 11 (SLC7A11), and glutathione peroxidase 4 (GPX4).

RESULTS

In rats with the MCAO/R model, CT demonstrated the ability to decrease ROS levels, enhance the activity of glutathione (GSH), mitigate inflammation, augment the activity of glutathione peroxidase 4 (GPX4), inhibit ferroptosis, safeguard neurons, and facilitate the restoration of nerve function. Results from network pharmacology indicated that the action of CT might be mediated via the PI3K/Akt signaling pathway. Simultaneously, in-vivo investigations revealed that CT curbs ferroptosis through the PI3K/AKT/Nrf2 and SLC7A11/GPX4 signaling pathways.

CONCLUSION

CT can inhibit ferroptosis by inhibiting the vicious cycle between oxidative stress and inflammation, protect neurons and promote motor function recovery.

Zwitterionic polymer-coated magnetic nanoparticle induced chemotherapy and ferroptosis for triple-negative breast cancer therapy

Triple-negative breast cancer (TNBC), an aggressive cancer with a high risk of metastasis and recurrence, is resistant to conventional chemotherapy. Ferroptosis, a non-apoptotic form of cell death, is primarily caused by excessive accumulation of lipid peroxides, and is closely associated with the occurrence and development of various diseases. Mounting evidence indicates that ferroptosis is becoming a promising treatment for TNBC based on its inherent characteristics. Herein, zwitterionic polymer poly (N-(3-sulfopropyl)-N-methacryloxyethyl-N,N-dimethylammonium betaine) (PSBMA)-coated gambogenic acid (GNA)-loaded magnetic composite nanoparticles (Fe3O4@PSBMA-GNA) were fabricated for chemotherapy combined with ferroptosis therapy for TNBC. Fe3O4@PSBMA-GNA achieved significant cytotoxicity against TNBC cell lines and contributed to the disruption of intracellular redox homeostasis. Furthermore, Fe3O4@PSBMA-GNA could induce apoptosis through the inhibition of Bcl-2 and trigger ferroptosis by inhibiting the PI3K/AKT/mTOR/GPX4 pathway in MDA-MB-231 cells simultaneously. Given the excellent blood circulation performance, Fe3O4@PSBMA-GNA enhanced tumor accumulation and showed a satisfactory tumor suppression effect on MDA-MB-231 tumor-bearing mice. This strategy of chemotherapy combined with ferroptosis therapy is expected to be a feasible treatment for refractory TNBC.

Pharmacotherapeutic Strategies for Fine Particulate Matter-Induced Lung and Cardiovascular Damage: Marketed Drugs, Traditional Chinese Medicine, and Biological Agents

Fine particulate matter (PM2.5), defined as airborne particles with a diameter of ≤ 2.5 μm, represents a major constituent of air pollution and has been globally implicated in exacerbating public health burdens by elevating morbidity and mortality rates associated with respiratory and cardiovascular diseases (CVDs). Adverse health effects of PM2.5 exposure manifest across diverse susceptibility profiles and durations of exposure, spanning both acute and chronic timelines. While prior reviews have predominantly focused on elucidating the toxicological mechanisms underlying PM2.5-induced pathologies, there remains a paucity of comprehensive summaries addressing therapeutic interventions for cardiopulmonary damage. This review systematically synthesizes pharmacological agents with potential therapeutic efficacy against PM2.5-induced pulmonary and cardiovascular injury. By integrating mechanistic insights with translational perspectives, this work aims to provide a foundational framework for advancing research into novel therapeutic strategies targeting PM2.5-associated cardiopulmonary disorders.

Effect of Particulate Matter 2.5 on Primary Gingival Keratinocyte and Human Gingival Fibroblast Cell Lines

OBJECTIVE

 Particulate matter 2.5 (PM2.5), an important air pollution particle, has been previously studied for its effects on various normal and cancer tissues. However, research on the impact of PM2.5, specifically on normal cavity tissue, is still limited. This study aimed to assess the effects of PM2.5 on cell vitality, cell cycle, and apoptosis in PGK (normal oral keratinocyte) and HGF (human gingival fibroblast) cell lines.

MATERIALS AND METHODS

 The effect of PM2.5 was examined through cell vitality using the Cell Counting Kit-8 (CCK8) assay, while cell cycle and apoptosis were determined via flow cytometry. Cells incubated with 0.05% dimethyl sulfoxide were used as the negative control.

RESULTS

 In a concentration-dependent manner, PM2.5 inhibited the proliferation of HGF and PGK cells. The half-maximal inhibitory concentration (IC50) of PM2.5 after 24 hours of incubation was 400 ng/µL for HGF cells and 100 ng/µL for PGK cells. This particulate matter arrested the cell cycles of both HGF and PGK cells at the G0/G1 phase. Additionally, PM2.5 was found to trigger apoptosis in both HGF and PGK cell lines and also cause necrosis in the PGK cell line at higher concentrations.

STATISTICAL ANALYSIS

 Kruskal-Wallis tests were employed to evaluate all quantitative data.

CONCLUSION

 The findings indicated that PM2.5 decreases cell viability, halts cell cycle progression, and triggers apoptosis in normal oral cavity cell lines. Therefore, it is advisable to avoid PM2.5 exposure in order to mitigate potential health risks. To understand PM2.5-induced oral cellular damage, more research is needed.

Propranolol and Capecitabine Synergy on Inducing Ferroptosis in Human Colorectal Cancer Cells: Potential Implications in Cancer Therapy

BACKGROUND/OBJECTIVES

Colorectal cancer (CRC) is a significant global health issue with rising incidence and mortality rates. In oncology, drug repurposing has emerged as a promising therapeutic strategy in conjunction with conventional treatments. This study aimed to evaluate the potential of repurposing propranolol (PRO), a beta blocker, for the treatment of CRC cell lines (HCT-116 and HT-29), both as a monotherapy and in combination with capecitabine (CAP).

METHODS

Effects of mono- and combination therapies on viability, combination index, morphology, and cell death induction of CRC cells were assessed. Transcriptome analysis of HT-29 cells was performed using RNA sequencing. Metabolite profiling was conducted, and changes in biochemical parameters were evaluated using flow cytometry and biochemical analyses.

RESULTS

The combination index showed that HT-29 cells were the most responsive to the combined treatment, even with PIK3CA, B-RAF (V600E), and TP53 mutations. Moreover, ferroptosis was synergistically activated in the combined group of HT-29 in comparison to control. Furthermore, we observed an increase in OXPHOS metabolites, along with elevated intracellular and mitochondrial ROS, disruption of mitochondrial membrane potential, and greater levels of malondialdehyde (MDA) in the HT-29 combined group, which are the features of ferroptosis. Furthermore, ferroptosis induction was coupled with necroptosis, as indicated by RNA-sequencing data. Combination therapy inhibited cell migration and enhanced the immune response of HT-29 cells.

CONCLUSIONS

These findings suggest that PRO is promising as a potential adjuvant therapy in combination with CAP for the treatment of CRC. Only HT-29 cells with the B-RAF (V600E) mutation showed promising findings in this study.

Duck House Inhalable Particulate Matter Induces Lung Injury by Activating Ferroptosis

The particulate matter (PM) generated during poultry farming is characterized by its complex composition and substantial emission levels. However, researches on the respiratory damage caused by poultry house PM and the underlying mechanisms remain limited. In this study, inhalable PM collected from duck houses was administered to experimental mice through inhalation exposure. After 10 days of short-term exposure and 30 days of long-term exposure, mice samples were collected for lung histopathological analysis and inflammatory cytokines detection. The results showed that inhalation of duck house PM induced pulmonary and systemic inflammatory responses in both groups of mice, with significant upregulation of IL-6 and CXCL2. Compared to short-term exposure, long-term exposure resulted in more severe microscopic lesions in the lungs. In addition, the concentrations of malondialdehyde (MDA) and glutathione (GSH) increased in mice, indicating that duck house PM could trigger oxidative stress in lungs, we also found duck house PM induced ferroptosis in mice. Furthermore, it was confirmed that duck house PM caused cell damage and increased intracellular iron levels in MLE-12 cells, and PM reduced GSH in a dose-dependent manner. Notably, ferroptosis inhibitor treatment effectively alleviated PM-induced cell damage. These findings indicated that duck house PM can induce ferroptosis in both mice and cells, and ferroptosis plays a critical role in duck house PM-induced lung damage. These results laid a solid foundation for further exploring the mechanism of PM-induced lung injury, and providing a new insight for targeting ferroptosis to treat such damage.

Life-threatening risk factors contribute to the development of diseases with the highest mortality through the induction of regulated necrotic cell death

Chronic diseases affecting the cardiovascular system, diabetes mellitus, neurodegenerative diseases, and various other organ-specific conditions, involve different underlying pathological processes. However, they share common risk factors that contribute to the development and progression of these diseases, including air pollution, hypertension, obesity, high cholesterol levels, smoking and alcoholism. In this review, we aim to explore the connection between four types of diseases with different etiologies and various risk factors. We highlight that the presence of risk factors induces regulated necrotic cell death, leading to the release of damage-associated molecular patterns (DAMPs), ultimately resulting in sterile inflammation. Therefore, DAMP-mediated inflammation may be the link explaining how risk factors can lead to the development and maintenance of chronic diseases. To explore these processes, we summarize the main cell death pathways activated by the most common life-threatening risk factors, the types of released DAMPs and how these events are associated with the pathophysiology of diseases with the highest mortality. Various risk factors, such as smoking, air pollution, alcoholism, hypertension, obesity, and high cholesterol levels induce regulated necrosis. Subsequently, the release of DAMPs leads to chronic inflammation, which increases the risk of many diseases, including those with the highest mortality rates.

Carbonaceous cores serve as surrogates for environmental particulate matter inducing vascular endothelial inflammation via inflammasome activation

Ambient particulate matter (PM) exposure is a known risk factor for cardiovascular diseases. Epidemiological studies have shown the association between PM exposure and vascular complications, including vasculitis, embolism, hypertension, stroke, and atherosclerosis. However, the exact mechanisms underlying its vascular toxicity, especially in relation to short-term exposures, remain incompletely understood. This study investigates the role of PM and its carbonaceous cores in driving vascular endothelial inflammation via inflammasome activation. We hypothesized that PM SRM1648a exposure induces vascular endothelial inflammation through oxidative stress and inflammasome activation. Short-term exposure to PM SRM1648a was assessed in BALB/c mice for systemic inflammation and oxidative stress biomarkers, alongside in vitro studies in HUVECs and EA.hy926 endothelial cells to elucidate inflammasome activation pathways. PM SRM1648a exposure significantly altered redox balance and cytokine profiles in mice and upregulated NLRP3/NLRC4 inflammasomes in vascular endothelial cells, leading to caspase-1/IL-1β activation. Intriguingly, pyroptosis was not the primary mode of cell death. In vitro studies demonstrated that antioxidants glutathione monoethyl ester effectively mitigated oxidative stress and inflammasome activation in endothelial cells. This study highlights the critical role of ROS-mediated inflammasome activation in vascular inflammation induced by PM SRM1648a, with carbon-based cores as key contributors.

Sodium Iodate-Induced Ferroptosis in Photoreceptor-Derived 661W Cells Through the Depletion of GSH

Oxidative stress-induced photoreceptor cell death is closely associated with the etiology of age-related macular degeneration (AMD), and sodium iodate (SI) has been widely used as an oxidant stimulus in AMD models to induce retinal pigment epithelium (RPE) and photoreceptor cell death. However, the mechanism underlying SI-induced photoreceptor cell death remains controversial and unclear. In this study, we elucidate that ferroptosis is a critical form of cell death induced by SI in photoreceptor-derived 661W cells. SI disrupts system Xc-, leading to glutathione (GSH) depletion and triggering lipid peroxidation, thereby promoting ferroptosis in photoreceptor-derived 661W cells. Additionally, SI enhances intracellular Fe2+ levels, which further facilitates reactive oxygen species (ROS) accumulation, making the 661W cells more susceptible to ferroptosis. Exogenous GSH, as well as specific inhibitors of ferroptosis such as Fer-1 and antioxidants like NAC, significantly attenuate SI-induced ferroptosis in photoreceptor-derived 661W cells. These findings provide new insights into the mechanisms of ferroptosis as a key pathway in SI-induced photoreceptor-derived 661W cell death.

Cell death crosstalk in respiratory diseases: unveiling the relationship between pyroptosis and ferroptosis in asthma and COPD

Asthma and chronic obstructive pulmonary disease (COPD) are heterogeneous obstructive diseases characterized by airflow limitations and are recognized as significant contributors to fatality all over the globe. Asthma accounts for about 4, 55,000 deaths, and COPD is the 3rd leading contributor of mortality worldwide. The pathogenesis of these two obstructive disorders is complex and involves numerous mechanistic pathways, including inflammation-mediated and non-inflammation-mediated pathways. Among all the pathological categorizations, programmed cell deaths (PCDs) play a dominating role in the progression of these obstructive diseases. The two major PCDs that are involved in structural and functional remodeling in the progression of asthma and COPD are Pyroptosis and Ferroptosis. Pyroptosis is a PCD mechanism mediated by the activation of the Nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) inflammasome, leading to the maturation and release of Interleukin-1β and Interleukin-18, whereas ferroptosis is a lipid peroxidation-associated cell death. In this review, the major molecular pathways contributing to these multifaceted cell deaths have been discussed, and crosstalk among them regarding the pathogenesis of asthma and COPD has been highlighted. Further, the possible therapeutic approaches that can be utilized to mitigate both cell deaths at once have also been illustrated.

Hesperetin alleviates PM2.5-induced lung injury by inhibiting ferroptosis in an Nrf2-dependent manner

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.

Copper-enriched automotive brake wear particles perturb human alveolar cellular homeostasis

BACKGROUND

Airborne fine particulate matter with diameter < 2.5 μm (PM2.5), can reach the alveolar regions of the lungs, and is associated with over 4 million premature deaths per year worldwide. However, the source-specific consequences of PM2.5 exposure remain poorly understood. A major, but unregulated source is car brake wear, which exhaust emission reduction measures have not diminished.

METHODS

We used an interdisciplinary approach to investigate the consequences of brake-wear PM2.5 exposure upon lung alveolar cellular homeostasis using diesel exhaust PM as a comparator. This involved RNA-Seq to analyse global transcriptomic changes, metabolic analyses to investigate glycolytic reprogramming, mass spectrometry to determine PM composition, and reporter assays to provide mechanistic insight into differential effects.

RESULTS

We identified brake-wear PM from copper-enriched non-asbestos organic, and ceramic brake pads as inducing the greatest oxidative stress, inflammation, and pseudohypoxic HIF activation (a pathway implicated in diseases associated with air pollution exposure, including cancer, and pulmonary fibrosis), as well as perturbation of metabolism, and metal homeostasis compared with brake wear PM from low- or semi-metallic pads, and also, importantly, diesel exhaust PM. Compositional and metal chelator analyses identified that differential effects were driven by copper.

CONCLUSIONS

We demonstrate here that brake-wear PM may perturb cellular homeostasis more than diesel exhaust PM. Our findings demonstrate the potential differences in effects, not only for non-exhaust vs exhaust PM, but also amongst different sources of non-exhaust PM. This has implications for our understanding of the potential health effects of road vehicle-associated PM. More broadly, our findings illustrate the importance of PM composition on potential health effects, highlighting the need for targeted legislation to protect public health.

Induction of GPX4-regulated ferroptotic stress promotes epithelial-to-mesenchymal transition in renal tubule cells induced by PM2.5

Increasing evidence links exposure to fine particulate matter (PM2.5) with an elevated risk of kidney disease. In this study, we investigated the effect of PM2.5 exposure on human proximal tubular epithelial (HK-2) cells and found that it elevated ferroptotic stress markers, including increased iron, reactive oxygen species (ROS), and malondialdehyde (MDA), along with reducing glutathione (GSH) levels. PM2.5 promotes the epithelial-to-mesenchymal transition (EMT) in these cells, which is associated with the loss of epithelial morphology, lowered expression of E-cadherin, and elevated expression of α-smooth muscle actin (α-SMA). Notably, a reduction in PM2.5-induced EMT characteristics was observed using either a ferroptosis-specific inhibitor (Fer-1) or a mitochondrial ROS scavenger (Mito-Tempo). Moreover, Fer-1 effectively counteracted ferroptotic stress and restored glutathione peroxidase 4 (GPX4) expression in PM2.5-exposed cells, which may explain its efficacy in inhibiting EMT induced by PM2.5. In contrast, GPX4 knockdown exacerbated EMT features in PM2.5-treated cells. Further studies showed that GPX4 overexpression alleviated EMT markers in mouse tubular cells following PM2.5 exposure, indicating the role of GPX4 in reducing ferroptotic stress and may prevent tubular injury caused by PM2.5 exposure. Our study highlights that PM2.5 may induce GPX4-regulated ferroptotic stress in tubular cells, potentially triggering the EMT process and contributing to kidney injury.

Hibiscus sabdariffa calyx extract protects human keratinocyte cells from fluoranthene-induced ferroptosis via the repression of aryl hydrocarbon receptor

Polycyclic aromatic hydrocarbons (PAHs) commonly associated with fine particulate matter (PM2.5) is gaining global concern because of their diverse biological toxicity. Fluoranthene (Flu) is a low molecular weight PAH and is reported to induce carcinogenicity, cardiotoxicity and skin damages. Currently, there are no effective treatment strategies to protect the host from PAHs, rather than avoiding the PAH exposure. The understanding of the impact and molecular mechanism of Flu toxicity on keratinocytes as well as effective protective mechanisms against the toxic outcomes remain limited. Herein, we explored the protective mechanism of Hibiscus sabdariffa (HS) calyxes ethanol extract against Flu toxicity in human keratinocyte HaCaT cells. In this study, biochemical assays, fluorescent microscopic imaging, real time PCR, western blot and in silico molecular docking analyses were employed. We found that pre-treatment of HS could restore Flu-induced reduction in cell viability through the inhibition of oxidative stress, augmenting antioxidant mechanism, modulation of aryl hydrocarbon receptor (AhR), constitutive androstane receptor (CAR)/pregnane X receptor (PXR)-mediated activation of phase I and II metabolism genes. Furthermore, the Flu-induced altered expression of gluconeogenesis-associated genes (G6PASE, PEPCK) and inhibition of ER-α expression were reversed with HS pre-treatment. The constituents of HS including pelargonidin 3-rhamnoside 5-glucoside, 7-methoxyisoflavone and 7,8-dihydroxycoumarin were identified to have phytoestrogenic potential as determined by docking analysis. Interestingly, our data also revealed for the first time the involvement of ferroptosis in Flu-induced keratinocyte cell death, which could be observed through the downregulation of FTH1, GPX4 and SLC7A11 protein expression upon Flu exposure, while the pre-treatment with ferroptosis inhibitor Ferrostatin-1 or HS extract significantly restored those changes. Overall, this present work highlights the harmful impact of Flu on human keratinocytes and underscores the potential of Hibiscus sabdariffa calyx extract as a natural source of protective agents against Flu-induced skin cytotoxicity, particularly through the repression of nuclear xenobiotic receptors and the attenuation of ferroptosis.

Oxidative potential determines the oxidative stress and ferroptotic toxicity of airborne particulate matter on pulmonary epithelial cells

Exposure to airborne particulate matter (PM) is a major risk which increases pulmonary diseases such as asthma, chronic bronchitis, or chronic obstructive pulmonary disease (COPD). PM is a complex mixture with physiochemical properties that can vary over time and space, presenting a challenge when attempting to analyze their health risks. In this study, we compared two kinds of commercial PM with real PM to explore an index which takes account of both the diverse physicochemical properties of PM and accurate prediction of their toxicities. Our results indicated that the oxidative potential (OP) of PM significantly affects their cytotoxicity. In comparison to two kinds of commercial PM such as carbon black and SRM-1648a, real ambient PM2.5 induced more significant oxidative stress and ferroptosis, which was closely associated with its higher OP. Notably, the use of radical scavengers like vitamin C and coumarin decreased the OP of PM2.5 effectively, thereby leading to a decrease in its cytotoxic effects. Furthermore, the reduction of OP reversed redox imbalance and alleviated lung damage in vivo. This study provides additional insights into the structure-activity relationship for PM's toxicity. It also sheds light on further investigations on the detoxication of PM.

Fluoride Induces Neurocytotoxicity by Disrupting Lysosomal Iron Metabolism and Membrane Permeability

The detrimental effects of fluoride on neurotoxicity have been widely recorded, yet the detailed mechanisms underlying these effects remain unclear. This study explores lysosomal iron metabolism in fluoride-related neurotoxicity, with a focus on the Steap3/TRPML1 axis. Utilizing sodium fluoride (NaF)-treated human neuroblastoma (SH-SY5Y) and mouse hippocampal neuron (HT22) cell lines, our research demonstrates that NaF enhances the accumulation of ferrous ions (Fe2+) in these cells, disrupting lysosomal iron metabolism through the Steap3/TRPML1 axis. Notably, NaF exposure upregulated ACSL4 and downregulated GPX4, accompanied by reduced glutathione (GSH) levels and superoxide dismutase (SOD) activity and increased malondialdehyde (MDA) levels. These changes indicate increased vulnerability to ferroptosis within neuronal cells. The iron chelator deferoxamine (DFO) mitigates this disruption. DFO binds to lysosomal Fe2+ and inhibits the Steap3/TRPML1 axis, restoring normal lysosomal iron metabolism, preventing lysosomal membrane permeabilization (LMP), and reducing neuronal cell ferroptosis. Our findings suggest that interference in lysosomal iron metabolism may mitigate fluoride-induced neurotoxicity, underscoring the critical role of the Steap3/TRPML1 axis in this pathological process.

Epigenetic regulation and post-translational modifications of ferroptosis-related factors in cardiovascular diseases

As an important element of the human body, iron participates in numerous physiological and biochemical reactions. In the past decade, ferroptosis (a form of iron-dependent regulated cell death) has been reported to contribute to the pathogenesis and progression of various diseases. The stability of iron in cardiomyocytes is crucial for the maintenance of normal physiological cardiac activity. Ferroptosis has been detected in many cardiovascular diseases (CVDs), including coronary heart disease, myocardial ischemia-reperfusion injury, heart failure, and chemotherapy-induced myocardial damage. In cardiomyocytes, epigenetic regulation and post-translational modifications regulate the expression of ferroptosis-related factors, maintain iron homeostasis, and participate in the progression of CVDs. Currently, there is no detailed mechanism to explain the relationship between epigenetic regulation and ferroptosis in CVDs. In this review, we provide an initial summary of the core mechanisms of ferroptosis in cardiomyocytes, with first focus on the epigenetic regulation and expression of ferroptosis-related factors in the context of common cardiovascular diseases. We anticipate that the new insights into the pathogenesis of CVDs provided here will inspire the development of clinical interventions to specifically target the active sites of these factors, reducing the harmfulness of ferroptosis to human health.

Gestational exposure to carbon black nanoparticles triggered fetal growth restriction in mice: The mediation of inactivating autophagy-lysosomal degradation system in placental ferroptosis

Carbon black nanoparticles (CBNPs) are ubiquitous in our daily ambient environment, either resulting from tobacco combustion or constituting the core of PM2.5. Despite the potential risk of trafficking CBNPs to the fetus, the underlying toxicity of nano-sized carbon black particles in the placenta remains unambiguous. Pregnant C57BL/6 mice received intratracheal instillation of 30 nm or 120 nm CBNPs. CBNPs deposited in the lungs could infiltrate the red blood cells, further cross into the placenta, and cause fetal growth restriction. Mechanistically, we proposed a two-hit hypothesis in placenta response to CBNPs. The first hit was that CBNPs caused mitochondrial damage, reflected in the reduced mitochondrial matrix, the excessive mitochondrial fission, and the decreased mitochondrial membrane potential and mtDNA copy number. The second hit was that CBNPs disrupted the autophagy-lysosomal degradation system, impeding the removal of dysfunctional mitochondria and resulting in ferroptosis. Ferrestatin-1, a ferroptosis inhibitor, and rapamycin, an autophagy promotor, reversed ferroptosis and further confirm our suspicion. The findings suggested that CBNPs-triggered double-hit evoked placental ferroptosis, leading to fetal growth restriction. The study raised concerns about the potential placental toxicity of CBNPs and its impact on the fetal adverse outcome, which may propose potential targets for interventions in placental damage.

Ambient fine particulate matter provokes multiple modalities of cell death via perturbation of subcellular structures

Fine particulate matter (PM2.5) is increasingly recognized for its detrimental effects on human health, with substantial evidence linking exposure to various forms of cell death and dysfunction across multiple organ systems. This review examines key cell death mechanisms triggered by PM2.5, including PANoptosis, necroptosis, autophagy, and ferroptosis, while other forms such as oncosis, paraptosis, and cuprotosis remain unreported in relation to PM2.5 exposure. Mitochondria, endoplasmic reticulum, and lysosomes emerge as pivotal organelles in the disruption of cellular homeostasis, with mitochondrial dysfunction particularly implicated in metabolic dysregulation and the activation of pro-apoptotic pathways. Although PM2.5 primarily affects the nucleus, cytoskeleton, mitochondria, endoplasmic reticulum, and lysosomes, other organelles like ribosomes, Golgi apparatus, and peroxisomes have received limited attention. Interactions between these organelles, such as endoplasmic reticulum-associated mitochondrial membranes, lysosome-associated mitophagy, and mitochondria-nuclei retro-signaling may significantly contribute to the cytotoxic effects of PM2.5. The mechanisms of PM2.5 toxicity, encompassing oxidative stress, inflammatory responses, and metabolic imbalances, are described in detail. Notably, PM2.5 activates the NLRP3 inflammasome, amplifying inflammatory responses and contributing to chronic diseases. Furthermore, PM2.5 exposure disrupts genetic and epigenetic regulation, often resulting in cell cycle arrest and exacerbating cellular damage. The composition, concentration, and seasonal variability of PM2.5 modulate these effects, underscoring the complexity of PM2.5-induced cellular dysfunction. Despite significant advances in understanding these pathways, further research is required to elucidate the long-term effects of chronic PM2.5 exposure, the role of epigenetic regulation, and potential strategies to mitigate its harmful impact on human health.

Impacts and potential mechanisms of fine particulate matter (PM2.5) on male testosterone biosynthesis disruption

Exposure to PM2.5 is the most significant air pollutant for health risk. The testosterone level in male is vulnerable to environmental toxicants. In the past, researchers focused more attention on the impacts of PM2.5 on respiratory system, cardiovascular system, and nervous system, and few researchers focused attention on the reproductive system. Recent studies have reported that PM2.5 involved in male testosterone biosynthesis disruption, which is closely associated with male reproductive health. However, the underlying mechanisms by which PM2.5 causes testosterone biosynthesis disruption are still not clear. To better understand its potential mechanisms, we based on the existing scientific publications to critically and comprehensively reviewed the role and potential mechanisms of PM2.5 that are participated in testosterone biosynthesis in male. In this review, we summarized the potential mechanisms of PM2.5 triggering the change of testosterone level in male, which involve in oxidative stress, inflammatory response, ferroptosis, pyroptosis, autophagy and mitophagy, microRNAs (miRNAs), endoplasmic reticulum (ER) stress, and N6-methyladenosine (m6A) modification. It will provide new suggestions and ideas for prevention and treatment of testosterone biosynthesis disruption caused by PM2.5 for future research.

The role of ferroptosis in environmental pollution-induced male reproductive system toxicity

This article provides a comprehensive review of the toxic effects of environmental pollution on the male reproductive system, with a particular emphasis on ferroptosis, a form of programmed cell death. Research has shown that environmental pollutants, such as heavy metals, pesticide residues, and plastic additives, can disrupt oxidative stress, increasing the production of reactive oxygen species (ROS) in germ cells. This disruption damages cellular lipids, proteins, and DNA, culminating in cell dysfunction or death. Ferroptosis, a cell death pathway closely linked to oxidative stress, is characterized by the accumulation of intracellular iron ions and elevated levels of lipid ROS. This review also explores the role of ferroptosis in male reproductive disorders, including its contributions to reduced sperm count, decreased motility, and abnormal morphology. Environmental pollutants, particularly heavy metals, can induce ferroptosis by interfering with intracellular antioxidant systems, notably the NRF2, GSH, and GPX4 pathways, accumulating toxic lipid peroxides. Furthermore, the article examines the potential interplay between ferroptosis and other forms of cell death, such as apoptosis, autophagy, pyroptosis, and necrosis, in the context of male reproductive health. The review underscores the critical need for further research into the link between environmental pollutants and male fertility, particularly focusing on ferroptosis. It advocates for targeted research efforts to mitigate the adverse effects of ferroptosis and protect reproductive health, emphasizing that a deeper understanding of these mechanisms could lead to innovative preventive strategies against environmental threats to fertility.

Deciphering the Liaison Between Fine Particulate Matter Pollution, Oxidative Stress, and Prostate Cancer: Where Are We Now?

Prostate cancer (PCa), a highly prevalent cancer in men worldwide, is projected to rise in the coming years. As emerging data indicate the carcinogenic effects of fine particulate matter (PM2.5) in lung cancer and other site-specific cancers, there is an urgent need to evaluate the relationship between this environmental risk factor and PCa as a potential target for intervention. The present review provides up-to-date evidence about the impact of airborne PM2.5 pollution on the initiation and progression of PCa. Examining the composition and characteristics of PM2.5 reveals its ability to induce toxic effects, inflammatory injuries, and oxidative damages. Additionally, PM2.5 can attach to endocrine-disrupting chemicals implicated in prostatic carcinogenesis. Considering the potential significance of oxidative stress in the risk of the disease, our review underlines the protective strategies, such as antioxidant-based approaches, for individuals exposed to increased PM2.5 levels. Moreover, the findings call for further research to understand the associations and mechanisms linking PM2.5 exposure to PCa risk as well as to suggest appropriate measures by policymakers, scientific researchers, and healthcare professionals in order to address this global health issue.

The roles and regulatory mechanisms of cigarette smoke constituents in vascular remodeling

Vascular remodeling is a dynamic process involving cellular and molecular changes, including cell proliferation, migration, apoptosis and extracellular matrix (ECM) synthesis or degradation, which disrupt the homeostasis of endothelial cells (ECs) and vascular smooth muscle cells (VSMCs). Cigarette smoke exposure (CSE) is thought to promote vascular remodeling, but the components are complex and the mechanisms are unclear. In this review, we overview the progression of major components of cigarette smoke (CS), such as nicotine and acrolein, involved in vascular remodeling in terms of ECs injury, VSMCs proliferation, migration, apoptosis, and ECM disruption. The aim was to elucidate the effects of different components of CS on different cells of the vascular system, to discover the relevance of their actions, and to provide new references for future studies.

Maternal exposure to nanopolystyrene induces neurotoxicity in offspring through P53-mediated ferritinophagy and ferroptosis in the rat hippocampus

There are increasing concerns regarding the rapid expansion of polystyrene nanoplastics (PS-NPs), which could impact human health. Previous studies have shown that nanoplastics can be transferred from mothers to offspring through the placenta and breast milk, resulting in cognitive deficits in offspring. However, the neurotoxic effects of maternal exposure on offspring and its mechanisms remain unclear. In this study, PS-NPs (50 nm) were gavaged to female rats throughout gestation and lactation to establish an offspring exposure model to study the neurotoxicity and behavioral changes caused by PS-NPs on offspring. Neonatal rat hippocampal neuronal cells were used to investigate the pathways through which NPs induce neurodevelopmental toxicity in offspring rats, using iron inhibitors, autophagy inhibitors, reactive oxygen species (ROS) scroungers, P53 inhibitors, and NCOA4 inhibitors. We found that low PS-NPs dosages can cause ferroptosis in the hippocampus of the offspring, resulting in a decline in the cognitive, learning, and memory abilities of the offspring. PS-NPs induced NOCA4-mediated ferritinophagy and promoted ferroptosis by inciting ROS production to activate P53-mediated ferritinophagy. Furthermore, the levels of the antioxidant factors glutathione peroxidase 4 (GPX4) and glutathione (GSH), responsible for ferroptosis, were reduced. In summary, this study revealed that consumption of PS-NPs during gestation and lactation can cause ferroptosis and damage the hippocampus of offspring. Our results can serve as a basis for further research into the neurodevelopmental effects of nanoplastics in offspring.

Role of iron homeostasis in the mutagenicity of disinfection by-products in mammalian cells

Disinfection by-products (DBPs) generated from water treatment have serious adverse effects on human health and natural ecosystems. However, research on the mutagenicity of DBPs with different chemical structures is still limited. In the present study, we compared the mutagenicity of 8 typical DBPs in human-hamster hybrid (AL) cells and clarified the mechanisms involved. Our data displayed that the rank order for mutagenicity was as follows: iodoacetamide (IAcAm) > iodoacetonitrile (IAN) > iodoacetic acid (IAA) > bromoacetamide (BAcAm) ≈ bromoacetonitrile (BAN) > bromoacetic acid (BAA), which was confirmed by DNA double strand breaks and oxidative DNA damage. In contrast, bromoform (TBM) and iodoform (TIM) had minimal mutagenicity. The mutation spectrum analysis further revealed that IAN, IAcAm, and IAA could induce multilocus deletions in mammalian cells. Interestingly, nitrogenous DBPs (N-DBPs) and IAA were found to cause varying degrees of iron overload and lipid peroxidation, which was mediated by the activation of the Nrf2/HO-1 signaling pathway. Moreover, the presence of deferoxamine (DFO), an iron ion inhibitor, effectively reduced γ-H2AX and 8-OHdG induced by N-DBPs and IAA. These results indicated that the variations in genotoxicity among DBPs with different structures were associated with their ability to disrupt iron homeostasis. This study provided new insights into the mechanisms underlying the structure-dependent toxicity of DBPs and established a foundation for a more comprehensive understanding and intervention of the health risks associated with DBPs.

Metallothionein ameliorates airway epithelial apoptosis upon particulate matter exposure: role of oxidative stress and ion homeostasis

Purpose

To investigate the mechanism underlying particulate matter (PM) exposure-induced oxidative stress and potential rescue strategies against pulmonary damage in this context.

Methods

A combination of omics technology and bioinformatic analysis were used to uncover mechanisms underlying cellular responses to PM exposure in human bronchial epithelia (HBE) cells and imply the potential rescue.

Results

Our results implicated that oxidative stress, metal ion homeostasis, and apoptosis were the major cellular responses to PM exposure in HBE cells. PM exposure disrupted oxidative phosphorylation (OXPHOS)-related gene expressions in HBE cells. Rescuing the expression of these genes with supplemental coenzyme Q10 (Co Q10) inhibited reactive oxygen species (ROS) generation; however, it only partially protected HBEs against PM exposure-induced apoptosis. Further, metallothionein (MT)-encoding genes associated with metal ion homeostasis were significantly induced in HBE cells, which was transcriptionally regulated by specificity protein 1 (SP1). SP1 knock-down (KD) aggravated PM-induced apoptosis in HBE cells, suggesting it plays a role in MT induction. Subsequent studies corroborated the protective role of MT by showing that exogenous MT supplement demonstrated effective protection against PM-induced oxidative stress and apoptosis in HBE cells. Importantly, exogenous MT supplement was shown to reduce ROS generation and apoptosis in airway epithelia in both HBE cells and a PM-inhaled murine model.

Conclusion

This study demonstrates that the impact of MT on airway epithelia by suppressing oxidative stress and maintaining metal ion homeostasis is beneficial in attenuating damage to pulmonary cells undergoing PM exposure.

In vitro assessment of ferroptosis of cells exposed to cigarette smoke aerosol using a self-designed on-chip evaluation system based on gas-liquid dual-dimensional exposure

Aerosol pollutants significantly cause health concerns. Herein, we established an original real-time aerosol exposure system that used a self-designed bionic-lung microfluidic chip. The chip features a 4 × 4 intersecting array within gas and liquid layers, creating 16 distinct microenvironments. A membrane situated between the layers offers attachment for cells and establishes a gas-liquid interface. This design provides a reliable screening capacity for investigating the biological effects of aerosol exposure in vitro by manipulating the gas and/or liquid conditions. Using this system, we validated that cigarette smoke (CS) aerosol triggered a concentration- and time-dependent reduction in cell viability and intracellular glutathione levels, accompanied by an increase in intracellular reactive oxygen species and Fe2+. Furthermore, CS aerosol significantly downregulated the expression of GPX4, SLC7A11, and FTL mRNA while inducing a notable increase in that of ACSL4 mRNA. Additionally, CS aerosol markedly stimulated the release of proinflammatory cytokines. Crucially, the ferroptosis inhibitor deferoxamine mesylate reversed these biological indicators. These results demonstrate that our novel bionic-lung chip presents a suitably achievable approach to investigate the biological effects induced by aerosol exposure.

Hepcidin depending on astrocytic NEO1 ameliorates blood-brain barrier dysfunction after subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) significantly compromises the blood-brain barrier (BBB) and impairs patient recovery. This study elucidates the critical role of astrocytic Neogenin-1 (NEO1) in BBB integrity post-SAH and examines the regulatory effects of hepcidin on endothelial cell (EC) function amid NEO1-mediated disruptions in iron homeostasis. Proteomic analyses of cerebrospinal fluid (CSF) from SAH patients revealed a substantial decrease in NEO1 expression, identifying it as a key factor in BBB integrity. 111 CSF proteins were significantly reduced in early SAH stages (days 1-3), with NEO1 among the most significantly altered. This dysregulation was linked to poorer patient outcomes, as indicated by a negative correlation between NEO1 levels and Modified Rankin Scale scores six months post-SAH (R = -0.4743, P < 0.0001). Experimental models further highlighted the importance of NEO1: SAH model and NEO1GFAP-Cre mice exhibited exacerbated EC dysfunction and increased BBB permeability, evidenced by significant Evans Blue retention and dextran leakage in the parietal cortex, effects that were mitigated by hepcidin administration. Our findings highlight the complex interplay between astrocytic signaling and endothelial function in SAH pathophysiology. The loss of astrocytic NEO1 led to increased EC proliferation and altered BBB structure, as confirmed by transmission electron microscopy and immunostaining for PECAM-1, indicating heightened blood vessel density in the affected cortex. Hepcidin treatment effectively reversed the EC dysfunction and BBB disruption in both NEO1-cKO mice and the SAH model, highlighting its potential as a therapeutic agent to enhance recovery and improve prognosis following SAH.

Soot nanoparticles promote ferroptosis in dopaminergic neurons via alteration of m6A RNA methylation in Parkinson's disease

Soot nanoparticles (SNPs) are black carbon prevalent in atmospheric environment with significant impacts on public health, leading to neurodegenerative diseases including development of Parkinson's disease (PD). This study investigated the effects of SNPs exposure on PD symptoms, employing both in vivo and in vitro PD models. In the in vivo experiments, animal behavior assessments showed that SNPs exposure exacerbated motor and cognitive impairments in PD mice. Molecular biology techniques further unveiled that SNPs aggravated degeneration of dopaminergic neurons. In vitro experiments revealed that SNPs exposure intensified ferroptosis of PD cells by increasing reactive oxygen species and iron ion levels, while reducing glutathione levels and mitochondrial membrane potential. Sequencing tests indicated elevated N6-methyladenosine (m6A) alteration of the ferroptosis-related protein, acyl-CoA synthetase long chain family member 4 (ACSL4). This study demonstrates that SNPs may exacerbate the onset and progression of PD by recruiting YTH domain-containing family protein 1 (YTHDF1) protein, enhancing m6A methylation in the ACSL4 5'UTR, amplifying ACSL4 protein expression, and accelerating the ferroptosis process in dopaminergic neurons. These molecular mechanisms underlying SNPs exacerbation of PD development may provide crucial insights for formulating environmental safety regulations and potential therapeutic strategies addressing PD in populations residing in regions with varied air quality.

Mechanism of ferroptosis regulating ischemic stroke and pharmacologically inhibiting ferroptosis in treatment of ischemic stroke

Ferroptosis is a newly discovered form of programmed cell death that is non-caspase-dependent and is characterized by the production of lethal levels of iron-dependent lipid reactive oxygen species (ROS). In recent years, ferroptosis has attracted great interest in the field of cerebral infarction because it differs morphologically, physiologically, and genetically from other forms of cell death such as necrosis, apoptosis, autophagy, and pyroptosis. In addition, ROS is considered to be an important prognostic factor for ischemic stroke, making it a promising target for stroke treatment. This paper summarizes the induction and defense mechanisms associated with ferroptosis, and explores potential treatment strategies for ischemic stroke in order to lay the groundwork for the development of new neuroprotective drugs.

PM2.5-induced ferroptosis by Nrf2/Hmox1 signaling pathway led to inflammation in microglia

Particulate matter (PM) has been a dominant contributor to air contamination, which will enter the central nervous system (CNS), causing neurotoxicity. However, the biological mechanism is poorly identified. In this study, C57BL/6J mice were applied to evaluate the neurotoxicity of collected fine particulate matter (PM2.5), via oropharyngeal aspiration at two ambient equivalent concentrations. The Y-maze results showed that PM2.5 exposure in mice would lead to the damage in hippocampal-dependent working memory. In addition, cell neuroinflammation, microglial activation were detected in hippocampus of PM2.5-exposure mice. To confirm the underlying mechanism, the microarray assay was conducted to screen the differentially expressed genes (DEGs) in microglia after PM2.5 exposure, and the results indicated the enrichment of DEGs in ferroptosis pathways. Furthermore, Heme oxygenase-1 (Hmox1) was found to be one of the most remarkably upregulated genes after PM2.5 exposure for 24 h. And PM2.5 exposure induced ferroptosis with iron accumulation through heme degradation by Nrf2-mediated Hmox1 upregulation, which could be eliminated by Nrf2-inhibition. Meanwhile, Hmox1 antagonist zinc protoporphyrin IX (ZnPP) could protect BV2 cells from ferroptosis. The results taken together indicated that PM2.5 resulted in the ferroptosis by causing iron overload through Nrf2/Hmox1 signaling pathway, which could account for the inflammation in microglia.

Characterization of Wildland Firefighters' Exposure to Coarse, Fine, and Ultrafine Particles; Polycyclic Aromatic Hydrocarbons; and Metal(loid)s, and Estimation of Associated Health Risks

Firefighters' occupational activity causes cancer, and the characterization of exposure during firefighting activities remains limited. This work characterizes, for the first time, firefighters' exposure to (coarse/fine/ultrafine) particulate matter (PM) bound polycyclic aromatic hydrocarbons (PAHs) and metal(loid)s during prescribed fires, Fire 1 and Fire 2 (210 min). An impactor collected 14 PM fractions, the PM levels were determined by gravimetry, and the PM-bound PAHs and metal(loid)s were determined by chromatographic and spectroscopic methodologies, respectively. Firefighters were exposed to a total PM level of 1408.3 and 342.5 µg/m3 in Fire 1 and Fire 2, respectively; fine/ultrafine PM represented more than 90% of total PM. Total PM-bound PAHs (3260.2 ng/m3 in Fire 1; 412.1 ng/m3 in Fire 2) and metal(loid)s (660.8 ng/m3 versus 262.2 ng/m3), distributed between fine/ultrafine PM, contained 4.57-24.5% and 11.7-12.6% of (possible/probable) carcinogenic PAHs and metal(loid)s, respectively. Firefighters' exposure to PM, PAHs, and metal(loid)s were below available occupational limits. The estimated carcinogenic risks associated with the inhalation of PM-bound PAHs (3.78 × 10-9 - 1.74 × 10-6) and metal(loid)s (1.50 × 10-2 - 2.37 × 10-2) were, respectively, below and 150-237 times higher than the acceptable risk level defined by the USEPA during 210 min of firefighting activity and assuming a 40-year career as a firefighter. Additional studies need to (1) explore exposure to (coarse/fine/ultrafine) PM, (2) assess health risks, (3) identify intervention needs, and (4) support regulatory agencies recommending mitigation procedures to reduce the impact of fire effluents on firefighters.

HO-1 upregulation promotes mitophagy-dependent ferroptosis in PM2.5-exposed hippocampal neurons

Fine particulate matter (PM2.5) has been extensively implicated in the pathogenesis of neurodevelopmental disorders, but the underlying mechanism remains unclear. Recent studies have revealed that PM2.5 plays a role in regulating iron metabolism and redox homeostasis in the brain, which is closely associated with ferroptosis. In this study, the role and underlying mechanism of ferroptosis in PM2.5-induced neurotoxicity were investigated in mice, primary hippocampal neurons, and HT22 cells. Our findings demonstrated that exposure to PM2.5 could induce abnormal behaviors, neuroinflammation, and neuronal loss in the hippocampus of mice. These effects may be attributed to ferroptosis induced by PM2.5 exposure in hippocampal neurons. RNA-seq analysis revealed that the upregulation of iron metabolism-related protein Heme Oxygenase 1 (HO-1) and the activation of mitophagy might play key roles in PM2.5-induced ferroptosis in HT22 cells. Subsequent in vitro experiments showed that PM2.5 exposure significantly upregulated HO-1 in primary hippocampal neurons and HT22 cells. Moreover, PM2.5 exposure activated mitophagy in HT22 cells, leading to the loss of mitochondrial membrane potential, alterations in the expression of autophagy-related proteins LC3, P62, and mTOR, as well as an increase in mitophagy-related protein PINK1 and PARKIN. As a heme-degradation enzyme, the upregulation of HO-1 promotes the release of excess iron, genetically inhibiting the upregulation of HO-1 in HT22 cells could prevent both PM2.5-induced mitophagy and ferroptosis. Furthermore, pharmacological inhibition of mitophagy in HT22 cells reduced levels of ferrous ions and lipid peroxides, thereby preventing ferroptosis. Collectively, this study demonstrates that HO-1 mediates PM2.5-induced mitophagy-dependent ferroptosis in hippocampal neurons, and inhibiting mitophagy or ferroptosis may be a key therapeutic target to ameliorate neurotoxicity following PM2.5 exposure.

New insight into air pollution-related cardiovascular disease: an adverse outcome pathway framework of PM2.5-associated vascular calcification

Despite the air quality has been generally improved in recent years, ambient fine particulate matter (PM2.5), a major contributor to air pollution, remains one of the major threats to public health. Vascular calcification is a systematic pathology associated with an increased risk of cardiovascular disease. Although the epidemiological evidence has uncovered the association between PM2.5 exposure and vascular calcification, little is known about the underlying mechanisms. The adverse outcome pathway (AOP) concept offers a comprehensive interpretation of all of the findings obtained by toxicological and epidemiological studies. In this review, reactive oxygen species generation was identified as the molecular initiating event (MIE), which targeted subsequent key events (KEs) such as oxidative stress, inflammation, endoplasmic reticulum stress, and autophagy, from the cellular to the tissue/organ level. These KEs eventually led to the adverse outcome, namely increased incidence of vascular calcification and atherosclerosis morbidity. To the best of our knowledge, this is the first AOP framework devoted to PM2.5-associated vascular calcification, which benefits future investigations by identifying current limitations and latent biomarkers.

Cadmium exposure induced neuronal ferroptosis and cognitive deficits via the mtROS-ferritinophagy pathway

Exposure to environmental cadmium (Cd) is known to cause neuronal death and cognitive decline in humans. Ferroptosis, a novel iron-dependent type of regulated cell death, is involved in various neurological disorders. In the present study, Cd exposure triggered ferroptosis in the mouse hippocampus and in the HT22 murine hippocampal neuronal cell line, as indicated by significant increases in ferroptotic marker expression, intracellular iron levels, and lipid peroxidation. Interestingly, ferroptosis of hippocampal neurons in response to Cd exposure relied on the induction of autophagy since the suppression of autophagy by 3-methyladenine (3-MA) and chloroquine (CQ) substantially ameliorated Cd-induced ferroptosis. Furthermore, nuclear receptor coactivator 4 (NCOA4)-mediated degradation of ferritin was required for the Cd-induced ferroptosis of hippocampal neurons, demonstrating that NCOA4 knockdown decreased intracellular iron levels and lipid peroxidation and increased cell survival, following Cd exposure. Moreover, Cd-induced mitochondrial reactive oxygen species (mtROS) generation was essential for the ferritinophagy-mediated ferroptosis of hippocampal neurons. Importantly, pretreatment with the ferroptosis inhibitor ferrostatin-1 (Fer-1) effectively attenuated Cd-induced hippocampal neuronal death and cognitive impairment in mice. Taken together, these findings indicate that ferroptosis is a novel mechanism underlying Cd-induced neurotoxicity and cognitive impairment and that the mtROS-ferritinophagy axis modulates Cd-induced neuronal ferroptosis.

Polycytosine RNA-binding protein 1 regulates osteoblast function via a ferroptosis pathway in type 2 diabetic osteoporosis

BACKGROUND

Recently, type 2 diabetic osteoporosis (T2DOP) has become a research hotspot for the complications of diabetes, but the specific mechanism of its occurrence and development remains unknown. Ferroptosis caused by iron overload is con-sidered an important cause of T2DOP. Polycytosine RNA-binding protein 1 (PCBP1), an iron ion chaperone, is considered a protector of ferroptosis.

AIM

To investigate the existence of ferroptosis and specific role of PCBP1 in the development of type 2 diabetes.

METHODS

A cell counting kit-8 assay was used to detect changes in osteoblast viability under high glucose (HG) and/or ferroptosis inhibitors at different concentrations and times. Transmission electron microscopy was used to examine the morphological changes in the mitochondria of osteoblasts under HG, and western blotting was used to detect the expression levels of PCBP1, ferritin, and the ferroptosis-related protein glutathione peroxidase 4 (GPX4). A lentivirus silenced and overexpressed PCBP1. Western blotting was used to detect the expression levels of the osteoblast functional proteins osteoprotegerin (OPG) and osteocalcin (OCN), whereas flow cytometry was used to detect changes in reactive oxygen species (ROS) levels in each group.

RESULTS

Under HG, the viability of osteoblasts was considerably decreased, the number of mitochondria undergoing atrophy was considerably increased, PCBP1 and ferritin expression levels were increased, and GPX4 expression was decreased. Western blotting results demonstrated that infection with lentivirus overexpressing PCBP1, increased the expression levels of ferritin, GPX4, OPG, and OCN, compared with the HG group. Flow cytometry results showed a reduction in ROS, and an opposite result was obtained after silencing PCBP1.

CONCLUSION

PCBP1 may protect osteoblasts and reduce the harm caused by ferroptosis by promoting ferritin expression under a HG environment. Moreover, PCBP1 may be a potential therapeutic target for T2DOP.

Orexin-A mediates glioblastoma proliferation inhibition by increasing ferroptosis triggered by unstable iron pools and GPX4 depletion

Glioblastoma (GBM) represents a prevalent form of primary malignant tumours in the central nervous system, but the options for effective treatment are extremely limited. Ferroptosis, as the most enriched programmed cell death process in glioma, makes a critical difference in glioma progression. Consequently, inducing ferroptosis has become an appealing strategy for tackling gliomas. Through the utilization of multi-omics sequencing data analysis, flow cytometry, MDA detection and transmission electron microscopy, the impact of orexin-A on ferroptosis in GBM was assessed. In this report, we provide the first evidence that orexin-A exerts inhibitory effects on GBM proliferation via the induction of ferroptosis. This induction is achieved by instigating an unsustainable increase in iron levels and depletion of GPX4. Moreover, the regulation of TFRC, FTH1 and GPX4 expression through the targeting of NFE2L2 appears to be one of the potential mechanisms underlying orexin-A-induced ferroptosis.

Immune Dysregulation in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a disease whose incidence increase with age and is characterised by chronic inflammation and significant immune dysregulation. Inhalation of toxic substances cause oxidative stress in the lung tissue as well as airway inflammation, under the recruitment of chemokines, immune cells gathered and are activated to play a defensive role. However, persistent inflammation damages the immune system and leads to immune dysregulation, which is mainly manifested in the reduction of the body's immune response to antigens, and immune cells function are impaired, further destroy the respiratory defensive system, leading to recurrent lower respiratory infections and progressive exacerbation of the disease, thus immune dysregulation play an important role in the pathogenesis of COPD. This review summarizes the changes of innate and adaptive immune-related cells during the pathogenesis of COPD, aiming to control COPD airway inflammation and improve lung tissue remodelling by regulating immune dysregulation, for further reducing the risk of COPD progression and opening new avenues of therapeutic intervention in COPD.

Analysis of the response to cigarette smoke exposure in cell coculture and monoculture based on bionic-lung microfluidic chips

BACKGROUND

In vitro toxicity assessment studies with various experimental models and exposure modalities frequently generate diverse outcomes. In the prevalent experimental, aerosol pollutants are dissolved in culture medium through capture for exposure to two-dimensional planar cellular models in multiwell plates via immersion. However, this approach can generate restricted and inconclusive experimental data, significantly constraining the applicability of risk assessment outcomes. Herein, the in vitro cocultivation of lung epithelial and/or vascular endothelial cells was performed using self-designed bionic-lung microfluidic chip housing a gas-concentration gradient generator (GCGG) unit. Exposure experiments involving a concentration gradient of cigarette smoke (CS) aerosol were then conducted through an original assembled real-time aerosol exposure system.

RESULTS

Transcriptomic analysis revealed a potential involvement of the cGMP-signaling pathway following online CS aerosol exposure on different cell culture models. Furthermore, distinct responses to different concentrations of CS aerosol exposure on different culture models were highlighted by detecting inflammation- and oxidative stress-related biomarkers (i.e., cell viability, reactive oxygen species, nitric oxide, IL-6, IL-8, TNF-α, GM-CSF, malondialdehyde, and superoxide dismutase).

SIGNIFICANT

The results underscore the importance of improving chip biomimicry while addressing multi-throughput demands, given the substantial influence of the coculture model on cellular responses triggered by CS. Furthermore, the coculture model exhibited a mutually beneficial protective effect on cells at low CS concentrations within the GCGG unit, yet revealed a mutually amplified damaging effect at higher CS concentrations in contrast to the monoculture model.

Unraveling the Molecular Regulation of Ferroptosis in Respiratory Diseases

Ferroptosis, a type of programmed cell death that relies on iron, is distinct in terms of its morphological, biochemical and genetic features. Unlike other forms of cell death, such as autophagy, apoptosis, necrosis, and pyroptosis, ferroptosis is primarily caused by lipid peroxidation. Cells that die due to iron can potentially trigger an immune response which intensifies inflammation and causes severe inflammatory reactions that eventually lead to multiple organ failure. In recent years, ferroptosis has been identified in an increasing number of medical fields, including neurological pathologies, chronic liver diseases and sepsis. Ferroptosis has the potential to cause an inflammatory tempest, with many of the catalysts and pathological indications of respiratory ailments being linked to inflammatory reactions. The growing investigation into ferroptosis in respiratory disorders has also garnered significant interest to better understand the mechanism of ferroptosis in these diseases. In this review, the recent progress in understanding the molecular control of ferroptosis and its mechanism in different respiratory disorders is examined. In addition, this review discusses current challenges and prospects for understanding the link between respiratory diseases and ferroptosis.

Environmental cadmium exposure perturbs systemic iron homeostasis via hemolysis and inflammation, leading to hepatic ferroptosis in common carp (Cyprinus carpio L.)

Cadmium (Cd) pollution is considered a pressing challenge to eco-environment and public health worldwide. Although it has been well-documented that Cd exhibits various adverse effects on aquatic animals, it is still largely unknown whether and how Cd at environmentally relevant concentrations affects iron metabolism. Here, we studied the effects of environmental Cd exposure (5 and 50 μg/L) on iron homeostasis and possible mechanisms in common carp. The data revealed that Cd elevated serum iron, transferrin saturation and iron deposition in livers and spleens, leading to the disruption of systemic iron homeostasis. Mechanistic investigations substantiated that Cd drove hemolysis by compromising the osmotic fragility and inducing defective morphology of erythrocytes. Cd concurrently exacerbated hepatic inflammatory responses, resulting in the activation of IL6-Stat3 signaling and subsequent hepcidin transcription. Notably, Cd elicited ferroptosis through increased iron burden and oxidative stress in livers. Taken together, our findings provide evidence and mechanistic insight that environmental Cd exposure could undermine iron homeostasis via erythrotoxicity and hepatotoxicity. Further investigation and ecological risk assessment of Cd and other pollutants on metabolism-related effects is warranted, especially under the realistic exposure scenarios.

Outdoor fine particulate matter exposure and telomere length in humans: A systematic review and meta-analysis

Although the association between changes in human telomere length (TL) and ambient fine particulate matter (PM2.5) has been documented, there remains disagreement among the related literature. Our study conducted a systematic review and meta-analysis of epidemiological studies to investigate the health effects of outdoor PM2.5 exposure on human TL after a thorough database search. To quantify the overall effect estimates of TL changes associated with every 10 μg/m3 increase in PM2.5 exposure, we focused on two main topics, which were outdoor long-term exposure and prenatal exposure of PM2.5. Additionally, we included a summary of short-term PM2.5 exposure and its impact on TL due to limited data availability. Our qualitative analysis included 20 studies with 483,600 participants. The meta-analysis showed a statistically significant association between outdoor PM2.5 exposure and shorter human TL, with pooled impact estimates (β) of -0.12 (95% CI: -0.20, -0.03, I2= 95.4%) for general long-term exposure and -0.07 (95% CI: -0.15, 0.00, I2= 74.3%) for prenatal exposure. In conclusion, our findings suggest that outdoor PM2.5 exposure may contribute to TL shortening, and noteworthy associations were observed in specific subgroups, suggesting the impact of various research variables. Larger, high-quality studies using standardized methodologies are necessary to strengthen these conclusions further.

PM2.5-induced premature senescence in HUVECs through the SIRT1/PGC-1α/SIRT3 pathway

Vascular endothelial cell senescence plays a pivotal role in the development of atherosclerosis. Recent studies have demonstrated that ambient fine particulate matter (PM2.5) induces stress-induced premature senescence (SIPS) in vascular endothelial cells. However, the precise mechanisms underlying this process remain to be fully elucidated. Cellular senescence is closely associated with reactive oxygen species (ROS), and emerging research has established a strong connection between the SIRT1/PGC-1α/SIRT3 signaling pathway and the antioxidant system in vascular endothelial cells. In this study, we aimed to investigate the impact of PM2.5 on vascular endothelial cell senescence and to elucidate the underlying mechanisms. Our findings revealed that PM2.5 exposure led to an increase in senescence-associated β-galactosidase (SA-β-gal) activity and the expression of the cell cycle-blocking proteins P53/P21 and P16 in human umbilical vein endothelial cells (HUVECs). Flow cytometry analysis demonstrated an elevated proportion of cells arrested in the G0/G1 phase after PM2.5 exposure. In addition, PM2.5-induced cellular senescence was attributed to the disruption of the cellular antioxidative defense system through the SIRT1/PGC-1α/SIRT3 signaling pathway. The expression of cellular senescence markers was reduced after targeted scavenging of mitochondrial ROS using MitoQ. Moreover, treatment with SRT1720, a SIRT1-specific activator, upregulated the SIRT1/PGC-1α/SIRT3 signaling pathway, restored the antioxidant system, and attenuated the expression of cellular senescence markers. Taken together, our results suggest that PM2.5 downregulates the SIRT1/PGC-1α/SIRT3 signaling pathway, resulting in impaired antioxidant defenses in HUVECs. This, in turn, allows for the accumulation of ROS, leading to inhibition of endothelial cell cycle progression and the onset of stress-induced senescence in HUVECs.

Phytochemical reduces toxicity of PM2.5: a review of research progress

Studies have shown that exposure to fine particulate matter (PM2.5) affects various cells, systems, and organs in vivo and in vitro. PM2.5 adversely affects human health through mechanisms such as oxidative stress, inflammatory response, autophagy, ferroptosis, and endoplasmic reticulum stress. Phytochemicals are of interest for their broad range of physiological activities and few side effects, and, in recent years, they have been widely used to mitigate the adverse effects caused by PM2.5 exposure. In this review, the roles of various phytochemicals are summarized, including those of polyphenols, carotenoids, organic sulfur compounds, and saponin compounds, in mitigating PM2.5-induced adverse reactions through different molecular mechanisms, including anti-inflammatory and antioxidant mechanisms, inhibition of endoplasmic reticulum stress and ferroptosis, and regulation of autophagy. These are useful as a scientific basis for the prevention and treatment of disease caused by PM2.5.

A single-cell atlas of lung homeostasis reveals dynamic changes during development and aging

Aging is a global challenge, marked in the lungs by function decline and structural disorders, which affects the health of the elderly population. To explore anti-aging strategies, we develop a dynamic atlas covering 45 cell types in human lungs, spanning from embryonic development to aging. We aim to apply the discoveries of lung's development to address aging-related issues. We observe that both epithelial and immune cells undergo a process of acquisition and loss of essential function as they transition from development to aging. During aging, we identify cellular phenotypic alternations that result in reduced pulmonary compliance and compromised immune homeostasis. Furthermore, we find a distinctive expression pattern of the ferritin light chain (FTL) gene, which increases during development but decreases in various types of lung cells during the aging process.

Ferroptosis contributing to cardiomyocyte injury induced by silica nanoparticles via miR-125b-2-3p/HO-1 signaling

BACKGROUND

Amorphous silica nanoparticles (SiNPs) have been gradually proven to threaten cardiac health, but pathogenesis has not been fully elucidated. Ferroptosis is a newly defined form of programmed cell death that is implicated in myocardial diseases. Nevertheless, its role in the adverse cardiac effects of SiNPs has not been described.

RESULTS

We first reported the induction of cardiomyocyte ferroptosis by SiNPs in both in vivo and in vitro. The sub-chronic exposure to SiNPs through intratracheal instillation aroused myocardial injury, characterized by significant inflammatory infiltration and collagen hyperplasia, accompanied by elevated CK-MB and cTnT activities in serum. Meanwhile, the activation of myocardial ferroptosis by SiNPs was certified by the extensive iron overload, declined FTH1 and FTL, and lipid peroxidation. The correlation analysis among detected indexes hinted ferroptosis was responsible for the SiNPs-aroused myocardial injury. Further, in vitro tests, SiNPs triggered iron overload and lipid peroxidation in cardiomyocytes. Concomitantly, altered expressions of TfR, DMT1, FTH1, and FTL indicated dysregulated iron metabolism of cardiomyocytes upon SiNP stimuli. Also, shrinking mitochondria with ridge fracture and ruptured outer membrane were noticed. To note, the ferroptosis inhibitor Ferrostatin-1 could effectively alleviate SiNPs-induced iron overload, lipid peroxidation, and myocardial cytotoxicity. More importantly, the mechanistic investigations revealed miR-125b-2-3p-targeted HO-1 as a key player in the induction of ferroptosis by SiNPs, probably through regulating the intracellular iron metabolism to mediate iron overload and ensuing lipid peroxidation.

CONCLUSIONS

Our findings firstly underscored the fact that ferroptosis mediated by miR-125b-2-3p/HO-1 signaling was a contributor to SiNPs-induced myocardial injury, which could be of importance to elucidate the toxicity and provide new insights into the future safety applications of SiNPs-related nano products.

The role of lysosomes in airborne particulate matter-induced pulmonary toxicity

An investigation of the potential role of lysosomes in airborne particulate matter (APM) induced health risks is essential to fully comprehend the pathogenic mechanisms of respiratory diseases. It is commonly accepted that APM-induced lung injury is caused by oxidative stress, inflammatory responses, and DNA damage. In addition, there exists abundant evidence that changes in lysosomal function are essential for cellular adaptation to a variety of particulate stimuli. This review emphasizes that disruption of the lysosomal structure/function is a key step in the cellular metabolic imbalance induced by APMs. After being ingested by cells, most particles are localized within lysosomes. Thus, lysosomes become the primary locus where APMs accumulate, and here they undergo degradation and release toxic components. Recent studies have provided incontrovertible evidence that a wide variety of APMs interfere with the normal function of lysosomes. After being stimulated by APMs, lysosome rupture leads to a loss of lysosomal acidic conditions and the inactivation of proteolytic enzymes, promoting an inflammatory response by activating the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome. Moreover, APMs interfere with autophagosome production or block autophagic flux, resulting in autophagy dysfunction. Additionally, APMs disrupt the normal function of lysosomes in iron metabolism, leading to disruption on iron homeostasis. Therefore, understanding the impacts of APM exposure from the perspective of lysosomes will provide new insights into the detrimental consequences of air pollution.

PM2.5 induce neurotoxicity via iron overload and redox imbalance mediated-ferroptosis in HT22 cells

PM2.5 is an important risk factor for the development and progression of cognitive impairment-related diseases. Ferroptosis, a new form of cell death driven by iron overload and lipid peroxidation, is proposed to have significant implications. To verify the possible role of ferroptosis in PM2.5-induced neurotoxicity, we investigated the cytotoxicity, intracellular iron content, iron metabolism-related genes, oxidative stress indices and indicators involving in Nrf2 and ferroptosis signaling pathways. Neurotoxicity biomarkers as well as the ferroptotic cell morphological changes were determined by Western Blot and TEM analysis. Our results revealed that PM2.5 induced cytotoxicity, lipid peroxidation, as indicated by MDA content, and neurotoxicity via Aβ deposition in a dose-related manner. Decreased cell viability and excessive iron accumulation in HT-22 cells can be partially blocked by ferroptosis inhibitors. Interestingly, GPX activity, Nrf2, and its regulated ferroptotic-related proteins (i.e. GPX4 and HO-1) were significantly up-regulated by PM2.5. Moreover, gene expression of DMT1, TfR1, IRP2 and FPN1 involved in iron homeostasis and NCOA4-dependent ferritinophagy were activated after PM2.5 exposure. The results demonstrated that PM2.5 triggered ferritinophagy-dependent ferroptotic cell death due to iron overload and redox imbalance. Activation of Nrf2 signaling pathways may confer a protective mechanism for PM2.5-induced oxidative stress and ferroptosis.